CN102574100A - Particulate water absorbent and method for producing same - Google Patents

Particulate water absorbent and method for producing same Download PDF

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Publication number
CN102574100A
CN102574100A CN2010800434161A CN201080043416A CN102574100A CN 102574100 A CN102574100 A CN 102574100A CN 2010800434161 A CN2010800434161 A CN 2010800434161A CN 201080043416 A CN201080043416 A CN 201080043416A CN 102574100 A CN102574100 A CN 102574100A
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China
Prior art keywords
water
weight
absorbing agent
agent
particulate water
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Inventor
中津留玲子
池内博之
北野贵洋
石崎邦彦
鸟井一司
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Nippon Shokubai Co Ltd
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Nippon Shokubai Co Ltd
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Application filed by Nippon Shokubai Co Ltd filed Critical Nippon Shokubai Co Ltd
Priority to CN201510663123.8A priority Critical patent/CN105363421A/en
Priority to CN201710139132.6A priority patent/CN107051402A/en
Publication of CN102574100A publication Critical patent/CN102574100A/en
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J20/00—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof
    • B01J20/22—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof comprising organic material
    • B01J20/26—Synthetic macromolecular compounds
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J20/00—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof
    • B01J20/22—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof comprising organic material
    • B01J20/26—Synthetic macromolecular compounds
    • B01J20/261—Synthetic macromolecular compounds obtained by reactions only involving carbon to carbon unsaturated bonds
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J20/00—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof
    • B01J20/02—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof comprising inorganic material
    • B01J20/0203—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof comprising inorganic material comprising compounds of metals not provided for in B01J20/04
    • B01J20/0259—Compounds of N, P, As, Sb, Bi
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J20/00—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof
    • B01J20/02—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof comprising inorganic material
    • B01J20/0203—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof comprising inorganic material comprising compounds of metals not provided for in B01J20/04
    • B01J20/0262—Compounds of O, S, Se, Te
    • B01J20/0266—Compounds of S
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J20/00—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof
    • B01J20/22—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof comprising organic material
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J20/00—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof
    • B01J20/22—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof comprising organic material
    • B01J20/26—Synthetic macromolecular compounds
    • B01J20/265—Synthetic macromolecular compounds modified or post-treated polymers
    • B01J20/267—Cross-linked polymers
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29B—PREPARATION OR PRETREATMENT OF THE MATERIAL TO BE SHAPED; MAKING GRANULES OR PREFORMS; RECOVERY OF PLASTICS OR OTHER CONSTITUENTS OF WASTE MATERIAL CONTAINING PLASTICS
    • B29B9/00—Making granules
    • B29B9/12—Making granules characterised by structure or composition
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J3/00—Processes of treating or compounding macromolecular substances
    • C08J3/12—Powdering or granulating
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J3/00—Processes of treating or compounding macromolecular substances
    • C08J3/12—Powdering or granulating
    • C08J3/128—Polymer particles coated by inorganic and non-macromolecular organic compounds
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J3/00—Processes of treating or compounding macromolecular substances
    • C08J3/24—Crosslinking, e.g. vulcanising, of macromolecules
    • C08J3/245—Differential crosslinking of one polymer with one crosslinking type, e.g. surface crosslinking
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J2220/00—Aspects relating to sorbent materials
    • B01J2220/50—Aspects relating to the use of sorbent or filter aid materials
    • B01J2220/68—Superabsorbents
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29B—PREPARATION OR PRETREATMENT OF THE MATERIAL TO BE SHAPED; MAKING GRANULES OR PREFORMS; RECOVERY OF PLASTICS OR OTHER CONSTITUENTS OF WASTE MATERIAL CONTAINING PLASTICS
    • B29B9/00—Making granules
    • B29B9/12—Making granules characterised by structure or composition
    • B29B2009/125—Micropellets, microgranules, microparticles
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J2300/00—Characterised by the use of unspecified polymers
    • C08J2300/14—Water soluble or water swellable polymers, e.g. aqueous gels
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J2333/00—Characterised by the use of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical, or of salts, anhydrides, esters, amides, imides, or nitriles thereof; Derivatives of such polymers
    • C08J2333/02—Homopolymers or copolymers of acids; Metal or ammonium salts thereof

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  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Health & Medical Sciences (AREA)
  • Polymers & Plastics (AREA)
  • Medicinal Chemistry (AREA)
  • Analytical Chemistry (AREA)
  • Inorganic Chemistry (AREA)
  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Solid-Sorbent Or Filter-Aiding Compositions (AREA)
  • Addition Polymer Or Copolymer, Post-Treatments, Or Chemical Modifications (AREA)
  • Absorbent Articles And Supports Therefor (AREA)

Abstract

Disclosed is a particulate water absorbent for an absorbent material, which is mainly composed of a polyacrylic acid (salt) water absorbent resin and exhibits excellent water absorption performance, while having excellent performance of preventing coloring over time. The particulate water absorbent has no odor and is suitable for practical use. Also disclosed is a method for producing a particulate water absorbent mainly composed of a polyacrylic acid (salt) water absorbent resin, which comprises: a step of polymerizing an aqueous monomer solution that is mainly composed of an acrylic acid (salt) that contains 10-200 ppm of a methoxyphenol; a step of drying a hydrated gel-like crosslinked polymer that is obtained by the polymerization; and a surface crosslinking step. The method for producing a particulate water absorbent is characterized by comprising a step of adding a chelating agent and an inorganic reducing agent and by satisfying the following condition (a) and/or (b). (a) The method comprises a step of adding water-insoluble inorganic fine particles. (b) In the drying step and the surface crosslinking step, the moisture content of the polymer is controlled to 3-15% by weight.

Description

Particulate water-absorbing agent and manufacturing approach thereof
Technical field
The present invention relates to a kind of with the particulate water-absorbing agent and the manufacturing approach thereof of polyacrylic acid (salt) water-absorbent resin as principal component.More detailed; Relate to particulate water-absorbing agent and manufacturing approach thereof as the absorber in paper nappy or the sanitary napkin etc.; And relate to the yellowing resistance excellence; No foul smell, and the performance superior absorption capacity with particulate water-absorbing agent and the manufacturing approach thereof of polyacrylic acid (salt) water-absorbent resin as principal component.
Background technology
In recent years, industry is developed has highly absorptive water-absorbing resins, and it mainly processes absorbent commodities such as paper nappy, sanitary napkin, and is used in the disposable purposes with water-loss reducer, industrial waterproof material etc. as agriculture and garden.As the raw material of this water-absorbing resins, propose to have the monomer or the hydrophilic macromolecule thing of a large amount of kinds.Wherein, be polyacrylic acid (salt) water-absorbent resin of monomer with acrylic acid and/or its salt, use at most in industry because its water absorbing properties is higher.
For this polyacrylic acid (salt) water-absorbent resin, before making acroleic acid polymerization or after the polymerization, it is neutralized into polyacrylate.In patent documentation 1～4 or non-patent literature 1, disclose technology relevant for this kind neutralization or polymerization.
As the water absorption character that said water-absorbing resins is expected; Known have or not to add depress water absorbent rate (CRC), add and depress water absorbent rate (AAP), absorption speed (FSR/Vortex), do not have to add and depress permeability for liquids, add many characteristics (parameter) such as depressing permeability for liquids, resistance to impact, urine patience, flowability, gel strength, color, granularity; In addition; Even if identical physical property (for example do not have to add and depress water absorbent rate) has also further proposed more regulation (parametric measurement method) from various viewpoints.
There is following problem in the water-absorbing resins that is conceived to these physical propertys and develops (particulate water-absorbing agent): even if control these physical propertys (for example " nothing add depress water absorbent rate (CRC) " or " add and depress water absorbent rate (AAP) " etc.); When being actually used in absorber such as paper nappy, also hard to sayly can give play to sufficient performance.
In addition; The main application of these water absorbing agents is hygienic materials such as paper nappy or sanitary napkin; Therefore in order to make water absorber of powder in hygienic material, not produce the foreign body sensation that causes by painted after compound with white paper pulp; (claim again: initial coloration), require water-absorbing resins to be white during shipment at the workshop for the initial stage tone of water absorbing agent.In addition, said water absorbing agent is generally white powder, but after dispatching from the factory; In its keeping or transportation; Or at it and then when the hygienic material, this water absorbing agent can painted along with effluxion (be dark brown by yellow coloring), therefore; For water absorbing agent in time through and for the tone that produces (claim: through time painted), also require absorbing articles after long-term keeping, still to be white.In recent years, the usage ratio (weight %) of water-absorbing resins in hygienic material has the tendency of increase, so coloring problem is more and more important.
To this, proposed in patent documentation 5～31 grades to be directed against the whiteness that improves water-absorbing resins and to prevent painted various motions.Particularly; As the control method of the polymerization inhibitor in the monomer, known: with the metoxyphenol in the acrylic acid be controlled to be 10～160ppm technology (patent documentation 5), with the hydroquinones in the acrylic acid be controlled at technology (patent documentation 6) below the 0.2ppm, utilize activated carbon handle the technology of monomer (patent documentation 7), with tocopherol as the technology (patent documentation 8) of inhibitor, with compound oxygen radical of nitrogen or manganese compound etc. as the technology (patent documentation 9) of polymerization inhibitor, use the technology (patent documentation 10,11) of metoxyphenol and specific multivalent metal salt etc.
In addition; Prevent agent as water-absorbing resins painted, known technology (patent documentation 12), the technology (patent documentation 13,14) of adding anti-oxidant of adding reducing agents such as hypophosphite arranged, add metal-chelator and add the technology (patent documentation 15～19) of other reducing agents etc., the technology (patent documentation 20～23) etc. of adding organic carboxyl acid and adding other compounds as required as required.
In addition, painted in order to prevent, as the technology that is conceived to polymerization initiator, the known technology that patent documentation 24～26 is arranged.In addition, about the technology (patent documentation 27,28) of the iron amount that causes painted material, also have being conceived in the aluminium or in the reducing agent.Also known with the acrylic acid ammonium salt as monomer, perhaps repeatedly add the compound of phosphorus atoms or the technology (patent documentation 29) that sulphur is reducing agent of containing.In addition, the also technology (patent documentation 30,31) of the oxygen amount in known control drying steps or the surface-crosslinked step etc.
Yet, adopt said patent documentation 5～31 prevent colorize method the time, continuous polymerization and particulate water-absorbing agent inequality is arranged on whiteness.Because industry is comparatively strict to the requirement of the whiteness of particulate water-absorbing agent, so on whiteness, still have room for improvement.In addition; Increasing substantially purity of raw materials such as acrylic acid; The polymerizing condition or the drying condition of water-absorbing resins are made as appropriateness; Perhaps use novel painted these existing preventing in the dye technology that prevent agent, the painted worry that prevents degradation problem under caused security of agent or the water absorption character that production cost rises or productivity descends, uses is arranged.
And then, except the coloring problem that discloses in the said patent documentation 5～31, also have the foul smell problem of water-absorbing resins itself, with water absorbing agent during as hygienic materials such as paper nappy or sanitary napkins, the no foreign odor of requirement before use is not to bring unplessantness displeasure to the user.In recent years, along with the high performance of water absorbing agent, the stench or the foreign odor that are derived from the material of new use become a problem sometimes.
To this; Propose the method for various minimizing foul smell, promptly reduced acrylic acid (patent documentation 32), acetate or propionic acid (patent documentation 33), volatile organic solvent (patent documentation 34), sulfur reduction agent (patent documentation 35), alcohol is the foul smell of volatile substance (patent documentation 36) etc.Yet; With regard to the excellent absorbability of the superiority of yellowing resistance, performance, these methods are also insufficient, using reducing agent to realize that high physical property is; Especially working as AAP (add and depress water absorbent rate) is more than 20 [g/g], and perhaps working as SFC (saline solution water conservancy diversion property) is 30 [* 10 -7Cm 3Sg -1] more than, the perhaps not clear foreign odor of the other reasons beyond absorption speed being made as 60 [sec] when following, can producing the foul smell that is derived from reducing agent.
[prior art document]
(patent documentation)
Patent documentation 1: No. 5210298 specification of United States Patent (USP)
Patent documentation 2: U.S. Patent application discloses specification No. 2008/242816
Patent documentation 3: No. 2007/28747 book of International Publication
Patent documentation 4: U.S. Patent application discloses specification No. 2008/194863
Patent documentation 5: No. 2003/051940 book of International Publication
Patent documentation 6: No. 6444744 specification of United States Patent (USP)
Patent documentation 7: No. 2004/052819 book of International Publication
Patent documentation 8: No. 2003/053482 book of International Publication
Patent documentation 9: No. 2008/096713 book of International Publication
Patent documentation 10: No. 2008/092843 book of International Publication
Patent documentation 11: No. 2008/092842 book of International Publication
Patent documentation 12: No. 6359049 specification of United States Patent (USP)
Patent documentation 13: No. 2009/060062 book of International Publication
Patent documentation 14: No. 2009/011717 book of International Publication
Patent documentation 15: U.S. Patent application discloses specification No. 2005/085604
Patent documentation 16: No. 2003/059961 book of International Publication
Patent documentation 17: No. 1645596 specification of European patent
Patent documentation 18: No. 3107873 communique of Japan's registered patent
Patent documentation 19: No. 2009/005114 book of International Publication
Patent documentation 20: No. 2008/026772 book of International Publication
Patent documentation 21: Japan's patent application open " spy opens the 2000-327926 communique "
Patent documentation 22: Japan's patent application open " spy opens the 2003-052742 communique "
Patent documentation 23: Japan's patent application open " spy opens the 2005-186016 communique "
Patent documentation 24: Japan's patent application open " spy opens flat 4-331205 communique "
Patent documentation 25: U.S. Patent application discloses specification No. 2006/089611
Patent documentation 26: No. 7528291 specification of United States Patent (USP)
Patent documentation 27: No. 2007/072969 book of International Publication
Patent documentation 28: U.S. Patent application discloses specification No. 2006/074160
Patent documentation 29: No. 2006/109882 book of International Publication
Patent documentation 30: U.S. Patent application discloses specification No. 2007/293632
Patent documentation 31: No. 2006/008905 book of International Publication
Patent documentation 32: No. 2004/052949 book of International Publication
Patent documentation 33: No. 2003/095510 book of International Publication
Patent documentation 34: U.S. Patent application discloses specification No. 2009/036855
Patent documentation 35: No. 2006/088115 book of International Publication
Patent documentation 36: U.S. Patent application discloses specification No. 2008/075937
(non-patent literature)
P.39～44 etc. non-patent literature 1:Modern Super absorbent Polymer Technology
Summary of the invention
The problem that institute of the present invention desire solves be to provide a kind of with polyacrylic acid (salt) water-absorbent resin as principal component; And can bring into play excellent absorption properties; And have excellent through the time the painted performance that prevents, no foul smell, suitable actual particulate water-absorbing agent and the manufacturing approach thereof that is used as absorber.In addition, the problem that institute of the present invention desire solves also is to provide a kind of urine patience excellent, suitable actual particulate water-absorbing agent and manufacturing approach thereof as absorber.
(particulate water-absorbing agent)
In order to solve said problem; Particulate water-absorbing agent of the present invention is with the particulate water-absorbing agent of polyacrylic acid (salt) water-absorbent resin as principal component; It is characterized in that: contain chelating agent and inorganic reducing agent; The content of this chelating agent is 0.001～0.5 weight %, and satisfies more than one important document in following (1)～(3)
(1) content of methoxybenzene phenols is 5～60ppm,
(2) contain the inorganic microparticle of water-insoluble,
(3) moisture content is 3～15 weight %.
(manufacturing approach of particulate water-absorbing agent)
In addition; In order to solve said problem; The manufacturing approach of particulate water-absorbing agent of the present invention is to be the manufacturing approach of the particulate water-absorbing agent of principal component with polyacrylic acid (salt) water-absorbent resin; It comprises that with acrylic acid (salt) be the polymerization procedure of the monomer solution of principal component, the drying steps and the surface-crosslinked step of aqueous gel shape cross-linked polymer that polymerization gets, it is characterized in that:
The interpolation step and the interpolation step of inorganic reducing agent that also comprise the chelating agent of 0.001～0.5 weight %;
When converting with respect to acrylic acid, monomer contains the methoxybenzene phenols of 10～200ppm; And more than one important document in (a)～(c) below satisfying,
(a) comprise the interpolation step of the inorganic microparticle of water-insoluble,
(b) behind drying steps, and in surface-crosslinked step, the moisture content of polymer is controlled at 3～15 weight %,
(c) after surface-crosslinked step, carry out the interpolation step of inorganic reducing agent.
(the suitable subordinate concept of said particulate water-absorbing agent)
(manufacturing approach 1 of particulate water-absorbing agent)
The manufacturing approach 1 of the subordinate concept of particulate water-absorbing agent manufacturing approach of the present invention; Must satisfy said (c), it is the manufacturing approach of the particulate water-absorbing agent that comprises the steps: with the acrylic acid (salt) that contains 10～200ppm methoxybenzene phenols is the drying steps of the polymerization procedure of the monomer solution of principal component, aqueous gel shape cross-linked polymer that polymerization gets, surface-crosslinked step, and the interpolation step of 0.001～0.5 weight % chelating agent.Manufacturing approach 1 is characterised in that: after surface-crosslinked step, carry out the interpolation step of inorganic reducing agent.State in embodiment 1-1～1-16 and table 1～5 after the concrete example of this manufacturing approach 1 will be shown in.
(manufacturing approach 2 of particulate water-absorbing agent)
The manufacturing approach 2 of the subordinate concept of particulate water-absorbing agent manufacturing approach of the present invention; Must satisfy said (b), it is the manufacturing approach of the particulate water-absorbing agent that comprises the steps: be drying steps, and the surface-crosslinked step of the polymerization procedure of the monomer solution of principal component, aqueous gel shape cross-linked polymer that polymerization gets with acrylic acid (salt).Manufacturing approach 2 is characterised in that: the interpolation step and the interpolation step of inorganic reducing agent that also comprise the chelating agent of 0.001～0.5 weight %; When converting with respect to acrylic acid, monomer contains the methoxybenzene phenols of 10～200ppm; The interpolation step that also comprises the inorganic microparticle of water-insoluble of (a).After will being shown in, the concrete example of this manufacturing approach 2 states in embodiment 2-1～2-14 and table 6～7.
(manufacturing approach 3 of particulate water-absorbing agent)
The manufacturing approach 3 of the subordinate concept of particulate water-absorbing agent manufacturing approach of the present invention; Must satisfy said (c), it is the manufacturing approach of the particulate water-absorbing agent that comprises the steps: be drying steps, and the surface-crosslinked step of the polymerization procedure of the monomer solution of principal component, aqueous gel shape cross-linked polymer that polymerization gets with acrylic acid (salt).Manufacturing approach 3 is characterised in that: the interpolation step and the interpolation step of inorganic reducing agent that also comprise the chelating agent of 0.001～0.5 weight %; When converting with respect to acrylic acid, monomer contains the methoxybenzene phenols of 10～200ppm; Behind the drying steps and/or in surface-crosslinked step, the moisture content of polymer is controlled at 3～15 weight %; And then preferably said inorganic reducing agent is added in the dry preceding aqueous gel shape cross-linked polymer.After will being shown in, the concrete example of this manufacturing approach 3 states in embodiment 3-1～3-13 and table 8～9.
[effect of invention]
According to particulate water-absorbing agent of the present invention, can provide a kind of have excellent through the time the painted performance that prevents, no foul smell and urine patience are excellent, the suitable actual particulate water-absorbing agent that is used as absorber.
Description of drawings
Fig. 1 is the side view of schematic configuration of determinator of the AAP (add and depress water absorbent rate) of present embodiment.
Fig. 2 is the side view of schematic configuration of determinator of the SFC (saline solution water conservancy diversion property) of present embodiment.
Fig. 3 is the electron micrograph of representative granulation thing.
[description of reference numerals]
The 31-storage tank
The 32-glass tube
33-0.69 the saline solution of weight %
34-band cock L type pipe
The 35-cock
The 40-container
The 41-groove
The stainless steel wire netting of 42-
The stainless steel wire netting of 43-
44-swelling gel
The 45-glass filter
The 46-piston
Hole in the 47-piston
The 48-trap receptacle
The 49-flat balance
The support cylinder of 100-plastics
The stainless steel 400 purpose wire nettings of 101-
102-swelling gel
The 103-piston
104-bear a heavy burden (counterweight)
The 105-culture dish
The 106-glass filter
107-filter paper
108-0.90 the saline solution of weight %
The specific embodiment
Below, the present invention will be described, but scope of the present invention and be not limited to these explanations except the hereinafter illustration, can be implemented suitably change in the scope of not damaging purport of the present invention.
At first, the abbreviation that hereinafter uses is defined.
In this manual, " CRC " (Centrifuge Retention Capacity) is meant " centrifugal separator maintenance capacity ", its be through after state the value of putting down in writing among the embodiment that assay method obtained.Also " CRC " is called " nothing add depress water absorbent rate " or abbreviates " water absorbent rate " as.In addition, " SFC " (Saline Flow Conductivity) is meant " saline solution water conservancy diversion property ", its be through after state the value of putting down in writing among the embodiment that assay method obtained.In addition, " AAP " (Absorbency against Pressure) is meant " add and depress water absorbent rate " corresponding to 4.83kPa or 2.0kPa pressure, its be through after state the value of putting down in writing among the embodiment that assay method obtained.In addition, " FSR " (Free Swell Rate) is meant " infiltration rate ", its be through after state the value of putting down in writing among the embodiment that assay method obtained.And then " D50 " (Distribution) is meant " weight average particle diameter ", its be through after state the value of putting down in writing among the embodiment that assay method obtained.In addition, " σ ζ " is meant " logstandard deviation of size distribution ", its be through after state the value of putting down in writing among the embodiment that assay method obtained." FHA " (Fixed Height Absorption) is meant " fixing high absorption ", its be through after state the value of putting down in writing among the embodiment that assay method obtained.In addition, " Vortex " is meant " absorption speed ", its be through after state the value of putting down in writing among the embodiment that assay method obtained.
In addition, in this manual, " saline solution " is meant " sodium-chloride water solution ", and " X～Y " of expression scope is meant " X is above and Y is following ".Short of special note, then " ppm " expression " ppm by weight " perhaps " quality ppm ", "～acid (salt) " expression "～sour and/or its salt ", " (methyl) acrylic acid " expression " acrylic acid and/or methacrylic acid ".
Particulate water-absorbing agent of the present invention is as principal component with polyacrylic acid (salt) water-absorbent resin; Contain chelating agent and inorganic reducing agent that content is 0.001～0.5 weight %; And more than one important document in (1)～(3) below satisfying, the absorption curing agent of waterborne liquid.
(1) content of methoxybenzene phenols is 5～60ppm,
(2) contain the inorganic microparticle of water-insoluble,
(3) moisture content is 3～15 weight %.
Particulate water-absorbing agent of the present invention is that the waterborne liquid that must satisfy more than one important document in said (1)～(3) absorbs curing agent, preferably satisfies more than two, especially preferably satisfies 3 simultaneously.But, prevent that then the effect of painted or deterioration can be lower if not in said scope and with chelating agent and inorganic reducing agent.For painted prevent or deterioration preventing for, said (1) methoxybenzene phenols and the inorganic microparticle of said (2) water-insoluble help to prevent deterioration, and then help to prevent painted.In addition, said (3) moisture content has influence on painted (the for example comparative example 3-8 in this specification), also helps absorption speed (the for example embodiment 1-16 in this specification), and then has also solved foul smell or dust problem.Wherein, in order to solve problem of the present invention, the content of preferably said (1) methoxybenzene phenols is 5～60ppm, and then preferably when said (3) moisture content is 3～15 weight %, contains the inorganic microparticle of said (2) water-insoluble.That is, come with said scope and method with chelating agent and inorganic reducing agent in, more than 1 of these important documents all to preventing painted or preventing that deterioration from exerting an influence, is selected in said (1)～(3) among the present invention, preferred more than 2, especially preferred 3.
In addition, " principal component " is meant: all with respect to water absorbing agent, the content of water-absorbing resins is more than the 50 weight %.With regard to the content of water-absorbing resins; In the water absorbing agent that must contain chelating agent and inorganic reducing agent is all, because preferred moisture content is 3～15 weight %, so contain water-absorbing resins less than 97 weight %; The following of water-absorbing resins is limited to more than the 60 weight %; And then be more than the 70 weight %, especially be more than the 80 weight %, and then be more than the 85 weight %.In addition; Under the situation of moisture content less than 3 weight %; The content of water-absorbing resins is more than the 60 weight % and less than 99.999 weight %; More preferably 70 weight % are above and less than 99.9 weight %, and then it is above and less than 99.7 weight % to be preferably 80 weight %, and it is above and less than 99.5 weight % especially to be preferably 90 weight %.
Particulate water-absorbing agent of the present invention is meant: the waterborne liquid that contains polyacrylic acid (salt) water-absorbent resin as principal component absorbs curing agent and (claims again: gelating agent).It is water that this waterborne liquid is not limited to; Also can enumerate: urine, blood, ight soil, waste liquid, moisture or steam, ice, water and organic solvent or and mixture of inorganic solvent, rainwater, underground water etc.; Water is then not special to be limited as long as contain; Preferably particulate water-absorbing agent of the present invention is used to urinate, in particular for the absorption curing agent of people's urine.
For so prevent or prevent deterioration that as preferably, particulate water-absorbing agent of the present invention is that the waterborne liquid that contains the alpha-hydroxy carboxylic acid compounds compound absorbs curing agent painted.
For so prevent deterioration and improve permeability for liquids that as preferably, the waterborne liquid that particulate water-absorbing agent of the present invention contains multivalent metal salt and/or cation property copolymer absorbs curing agent.In the past, when using multivalent metal salt and/or cation property copolymer, be easy to generate the coloring problem of gained water absorbing agent, but there was not this problem in the present invention.
As said particulate water-absorbing agent of the present invention, the performance excellent absorption properties can be provided, and have the painted performance that prevents between excellent warp, no foul smell and urine patience excellence, suitable actual particulate water-absorbing agent as absorber.
Below, in regular turn [1] polyacrylic acid (salt) water-absorbent resin, [2] chelating agent, [3] inorganic reducing agent, [4] methoxybenzene phenols, the inorganic microparticle of [5] water-insoluble, [6] alpha-hydroxy carboxylic acid compounds compound, [7] multivalent metal salt and/or cation property copolymer, [8] granulation, [9] particulate water-absorbing agent, the manufacturing approach of [10] particulate water-absorbing agent, [11] water-absorbing body are described.
[1] polyacrylic acid (salt) water-absorbent resin
(1-1) monomer
Employed water-absorbing resins at random contains the grafting composition in the particulate water-absorbing agent of the present invention, and has and be derived from acrylic acid formation unit.Preferred this water-absorbing resins has as the acrylic acid formation of being derived from of principal component unit.The manufacturing approach of this water-absorbing resins does not have special qualification, is that the monomer component of principal component carries out polymerization but preferably make with acrylic acid and/or its salt, obtains this water-absorbing resins.
In addition, about the structure of the formation unit that is derived from said monomer, for example be the equal of the structure that the two keys of polymerism of each monomer are opened.The two keys of polymerism are opened the structure that forms and are meant that for example the two keys (C=C) between carbon become singly-bound (structure C-C-).
In the present invention, employed water-absorbing resins is in the particulate water-absorbing agent, through in polymer, importing the water-insoluble polymer of water-swellable that cross-linked structure obtains.
In addition, " water-swellable " is meant: the nothing of normal saline solution is added to depress water absorbent rate (CRC) be more than 2 [g/g], be preferably 5～200 [g/g], more preferably 20～100 [g/g]." water-insoluble " is meant: the water soluble composition in the water-absorbing resins must be at the substantial water-insoluble below the 50 weight %, and said water soluble composition is 0～25 weight % preferably, is more preferably 0～15 weight %, and then 0～10 weight % preferably.These " water-swellable (CRC) ", " water-insoluble (water soluble composition) " are to try to achieve through the assay method of defined among the following embodiment.
In addition; In the present invention; Polyacrylic acid (salt) water-absorbent resin is meant: the acrylic acid in whole monomers (except the crosslinking agent) of confession polymerization and/or the total mole % of its salt are necessary for polyacrylic acid (salt) water-absorbent resin of 50～100 moles of %; A said total mole % is more preferably 70～100 moles of %, and then 90～100 moles of % preferably, especially preferably is essentially 100 moles of %.In addition, polyacrylic notion is not limited to refer to the polymerizing acrylic acid thing, also comprises the polyacrylic acid (salt) as polyacrylonitrile or HYDROLYSIS OF POLYACRYLAMIDE AND ITS COPOLYMERS thing, with regard to physical property, preferably through after the polyacrylic acid that acroleic acid polymerization obtained stated.
As the acrylates that uses among the present invention, use alkali metal salts such as lithium salts, sodium salt, sylvite usually; Ammonium salt; Acrylic acid 1 valency salt such as amine salt.Preferred acrylic acid alkali metal salt, more preferably acrylic acid sodium salt or the sylvite of using.In addition, have under the prerequisite of water-swellable, also can and use multivalent metal salts such as calcium salt, aluminium salt.
Neutralization ratio about the water-absorbing resins that obtains among the present invention; It is 10 moles more than the % and preferably less than 90 moles of % with respect to acidic group; Being 40 moles more than the % and less than 80 moles of % with respect to acidic group more preferably, is 50 moles more than the % and less than 74 moles of % with respect to acidic group more preferably.If so the situation that neutralization ratio less than 10 moles of %, then exists absorbent properties decline, especially water absorbent rate obviously to descend is not good enough.In addition, if neutralization ratio is 90 moles more than the %, then can't obtain sometimes absorbent properties higher, especially add and depress the higher water absorbing agent of water absorbent rate, so not good enough.In addition, with regard to the viewpoint of absorbent properties, especially preferably neutralization ratio is controlled to less than 74 moles of %, and then preferably neutralization ratio is controlled to less than 72 moles of %.That is, in the method for the invention, if neutralization ratio is too high, then also has painted tendency takes place, therefore the upper limit with neutralization ratio is located in the said scope.
Also can impose above-mentioned neutralization procedure to the monomer component before the polymerization, also can in the polymerization process or polymerization after aqueous gel shape cross-linked polymer impose said neutralization procedure.And, also can and with the neutralization of monomer component, and the neutralization of aqueous gel shape cross-linked polymer.Preferably the acrylic acid to as monomer component the time neutralizes.
Moisture content (by the assay method defined of this specification) about the water-absorbing resins that obtains among the present invention; Preferably in following drying steps or surface-crosslinked step etc.; In the scope of stating after moisture content is adjusted at, or the moisture content of the particulate water-absorbing agent of final manufactured goods is adjusted into 3～15 weight %.Certainly, if the important document of prepared particulate water-absorbing agent unmet of the present invention said (1) and (2), then must the moisture content of the particulate water-absorbing agent of final manufactured goods be adjusted to 3～15 weight %.If moisture content is higher than 15 weight %, the water absorbing agent that then obtains has painted tendency, if moisture content less than 3 weight %, then produces problems such as foul smell or dust sometimes.
(1-2) acrylic acid (salt) monomer in addition
In the present invention, not only under said scope with acrylic acid (salt) as monomer, can also and with the monomer beyond it.When using in addition monomer of acrylic acid (salt), with respect to as the acrylic acid (salt) of principal component and the total amount of other monomers, the use amount of acrylic acid (salt) monomer in addition is 0～50 mole of %, is preferably 0～30 mole of %, more preferably 0～10 mole of %.Through use acrylic acid (salt) monomer in addition according to said ratio, can further improve the absorption characteristic of the particulate water-absorbing agent of final acquisition, and can obtain particulate water-absorbing agent more at an easy rate.
About and the monomer except that acrylic acid (salt) of usefulness, for example can enumerate illustrative monomer in following United States Patent (USP) or the European patent.Particularly, as and the monomer of usefulness, can enumerate water-soluble or hydrophobic unsaturated monomer etc.About water-soluble or hydrophobic unsaturated monomer; For example can enumerate: methacrylic acid, maleic acid (acid anhydride), fumaric acid, butenoic acid, itaconic acid, vinyl sulfonic acid, 2-(methyl) acrylamide-2-methyl propane sulfonic acid, (methyl) acryloxy alkyl sulfonic acid and alkali metal salt thereof, ammonium salt; N-vinyl-2-Pyrrolidone, N-vinyl acetamide, (methyl) acrylamide, N-isopropyl (methyl) acrylamide, N, N-dimethyl (methyl) acrylamide, (methyl) acrylic acid 2-hydroxy methacrylate, methoxy poly (ethylene glycol) (methyl) acrylic acid ester, polyethylene glycol (methyl) acrylic acid ester, isobutene, (methyl) lauryl acrylate etc.In the particulate water-absorbing agent of the present invention, the compound that also to contain with said water-soluble or hydrophobic unsaturated monomer be the combined polymerization composition.
(1-3) internal crosslinking agent
The not special restriction of the cross-linking method that adopts among the present invention, for example can enumerate following method: in polymerization process and/or after polymerization, add crosslinking agent and carry out the crosslinked method in back, utilize radical polymerization initiator carry out radical crosslinking method, utilize electron beam etc. to carry out the crosslinked method of radioactive ray etc.The preferred in advance internal crosslinking agent of ormal weight the interpolation to monomer carries out polymerization, and in polymerization or after polymerization, carries out the method for cross-linking reaction.
As the internal crosslinking agent that uses among the present invention; For example can enumerate: N, N '-methylene-bisacrylamide, (gathering) ethylene glycol bisthioglycolate (methyl) acrylic acid ester, (gathering) propane diols two (methyl) acrylic acid ester, (polyoxyethylene) trimethylolpropane tris (methyl) acrylic acid ester, (polyoxyethylene) glycerine three (methyl) acrylic acid ester, trimethylolpropane two (methyl) acrylic acid ester, polyethylene glycol two (β-acryloxy propionic ester), trimethylolpropane tris (β-acryloxy propionic ester), gather (methyl) allyloxy alkane, polyethyleneglycol diglycidylether, ethylene glycol, propane diols, glycerine, butanediol, erythrol, xylitol, D-sorbite, polyethylene glycol etc.Can use in these compounds a kind or more than 2 kinds.In addition,, consider the absorption characteristic of the water-absorbing resins that is obtained etc. so, must use compound during preferred polymeric with 2 above polymerism unsaturated groups if use the internal crosslinking agent more than a kind.
With respect to said monomer, the use amount of internal crosslinking agent is preferably 0.005～2 mole of %, 0.01～1 mole of % more preferably, and then be preferably 0.05～0.2 mole of %.If the use amount of said internal crosslinking agent is less than 0.005 mole of % or more than 2 moles of %, the worry that can't obtain required absorption characteristic is arranged then.
(1-4) polymerization concentration
If monomer component is processed the aqueous solution, so in polymerization procedure, the concentration of the monomer component in this aqueous solution (below be called monomer solution) can be come suitably decision according to the kind or the target physical character of monomer, not special the qualification.From the physical property aspect, the concentration of monomer component is preferably 10～70 weight %, 15～65 weight % more preferably, and then be preferably 30～55 weight %.Further, as needed, and a solvent other than water, the solvent used and the kind is not particularly limited.In addition, can process the slurry that monomer concentration surpasses saturated concentration, but monomer concentration is preferably in said scope, more preferably below saturated concentration.
(1-5) other compositions
During polymerization; With respect to being the monomer of principal component with acrylic acid (salt); Can add 0～50 weight %'s for example; The preferably water-soluble resin of 0～20 weight % (for example starch, cellulose, polyvinyl alcohol) or water-absorbing resins (or its micro mist) are to improve the various physical propertys of water-absorbing resins.In addition; When polymerization; With respect to monomer, also can add 0～5 weight % for example, the various blowing agents of preferred 0～1 weight % (carbonate, azo-compound, bubble etc.), surfactant, chelating agent, chain-transferring agent wait the various physical propertys of improving water-absorbing resins.In addition, as employed said water-soluble resin or water-absorbing resins, though interpolation is graft polymers (for example starch-grafted polymer or PVA graft polymers), these polymer are referred to as polyacrylic acid (salt) water-absorbent resin in the present invention.
(1-6) polymerization procedure
Can use inverse suspension polymerization, aqueous solution polymerization, spraying or polymerization of fluid drops among the present invention.When making said monomer solution generation polymerization, with regard to the easy degree of aspect of performance and control polymerization, preferably carry out polymerization through aqueous solution polymerization or inverse suspension polymerization.These polymerizations can be implemented under air ambient, but preferably under the environment (for example oxygen is below the 1 volume %) of inert gases such as nitrogen or argon gas, carry out polymerization.In addition, preferably fully replaced dissolved oxygen (for example oxygen is less than 1 [mg/L]) with inert gas after, monomer component is used for polymerization.The present invention has high productivity, is particularly suited for to obtaining the water-absorbing resins of high physical property, and the polymerization Control aqueous solution polymerization of difficulty comparatively.As especially preferred aqueous solution polymerization, can enumerate: continuous band polymerization (on the books in No. the 4893999th, United States Patent (USP), No. the 6241928th, United States Patent (USP) or U.S. Patent application disclose No. 2005/215734 etc.), continuously or batch kneader polymerization (on the books in No. the 6710141st, No. the 6987151st, United States Patent (USP) or United States Patent (USP) etc.).
Aqueous solution polymerization is meant, under the situation of not using dispersion solvent, makes the method for monomer solution generation polymerization.Aqueous solution polymerization is for example in United States Patent (USP)s such as No. the 4625001st, United States Patent (USP), No. the 4873299th, United States Patent (USP), No. the 4286082nd, United States Patent (USP), No. the 4973632nd, United States Patent (USP), No. the 4985518th, United States Patent (USP), No. the 5124416th, United States Patent (USP), No. the 5250640th, United States Patent (USP), No. the 5264495th, United States Patent (USP), No. the 5145906th, United States Patent (USP), No. the 5380808th, United States Patent (USP), and is and on the books in European patents such as No. the 0811636th, European patent, No. the 0955086th, European patent, No. the 0922717th, European patent, No. the 1178059th, European patent.The monomer of putting down in writing in these United States Patent (USP)s or the European patent, crosslinking agent, polymerization initiator, other additive also can use in the present invention.
Inverse suspension polymerization is meant, makes monomer solution be suspended in the polymerization in the hydrophobic organic solvent.It is for example on the books in United States Patent (USP)s such as No. the 4093776th, United States Patent (USP), No. the 4367323rd, United States Patent (USP), No. the 4446261st, United States Patent (USP), No. the 4683274th, United States Patent (USP), No. the 5244735th, United States Patent (USP).
And, among the present invention, when making said monomer generation polymerization; In order to realize problem of the present invention, promptly for improve absorption characteristic or prevent through the time painted, the total ascent time till when the moment of self-adjusting monomer component plays polymerization and begins is short more good more; This total ascent time is preferably in 24 hours; Be more preferably in 12 hours, and then preferably in 3 hours, especially preferably in 1 hour.
Owing to be in storage tank, to neutralize in large quantities or adjust monomer component in the industry; So the holdup time is that the said total ascent time usually can be above 24 hours; It is long more to have adjusted the time and/or the time behind the acrylic acid (said total ascent time) that neutralized behind the monomer component, just can take place more the increase of remaining monomer and the xanthochromia phenomenon of water-absorbing resins (through the time painted).Therefore, in order to realize shortening the holdup time, preferred neutralization continuously reaches adjustment monomer component continuously, and carries out batch polymerization or continuous polymerization, and then preferably carries out continuous polymerization.
In aqueous solution polymerization method, the polymerization initiation temperature of the preferred monomers aqueous solution is more than 40 ℃, and then preferred more than 50 ℃, and then preferred more than 60 ℃, especially preferred high temperature polymerization more than 70 ℃.If to through this high temperature polymerization (high temperature begins polymerization) and aqueous gel use manufacturing approach of the present invention, then comprise granularity control effect, can bring into play effect of the present invention to greatest extent.Be limited to the boiling point of the aqueous solution on the initial temperature, preferably below 105 ℃.
In addition, the peak temperature of preferable polymerization temperature is more than 95 ℃, more preferably more than 100 ℃, and then preferred high temperature polymerization (boiling polymerization) more than 105 ℃.If the aqueous gel that will get through the boiling polymerization is applied to the present invention, then comprise granularity control effect, can bring into play effect of the present invention to greatest extent.In addition, be limited on the polymerization temperature boiling point just can, preferably below 130 ℃, and then preferably below 120 ℃.
In order further to bring into play effect of the present invention, polymerization procedure is water-soluble fluidity polymerization.To aqueous solution polymerization, can be in advance in and acrylic acid, also can after polymerization, neutralize.For the water absorbent rate (CRC) that improves mutual exclusion and the relativeness of solvable composition, comprised the sectionalization step of the aqueous gel shaped polymer in polymerization process or after polymerization.Monomer is a principal component with acrylic acid, and comprises the neutralization procedure of the aqueous gel shape cross-linked polymer after the polymerization.
And if after polymerization, mix reducing agent, then high sometimes crosslinked polymeric gel is higher owing to its gel strength, and can be difficult to mix nertralizer or reducing agent.Therefore, from mixed uniformly easy degree, preferably make after the polymerization and dry before aqueous gel shape cross-linked polymer further crosslinked.When crosslinked, can with after state surface crosslinking agent likewise, use can with the crosslinking agent of carboxyl reaction, can use poly epihydric alcohol based compound, poly hydroxyl compound etc. aptly.The use amount of crosslinking agent is with respect to monomer, preferably in the scope of 0.001～2 mole of %, and then preferably in the scope of 0.01～1 mole of %, and especially preferred suitably decision in the scope of 0.05～0.5 mole of %.
In addition, polymerization time is not special to be limited, and can wait suitably decision according to kind, the reaction temperature of hydrophilic monomer and polymerization initiator, is generally 0.5 minute～3 hours, preferred 1 minute～1 hour.
In addition; For the methoxybenzene phenols (especially metoxyphenol) in the water absorbing agent that obtains is controlled (preferably is 5～60ppm) in water absorbing agent; Preferred following polymerization procedure among the present invention: in containing 10～200ppm methoxybenzene phenols (especially p methoxy phenol); In maximum temperature is below 130 ℃ and polymerization time is under 0.5 minute～3 hours the condition; Utilize 0.001～1 mole of % radical polymerization initiator, make the monomer solution of monomer concentration 30～55 weight % that comprise 90～100 moles of % acrylic acid (salt) carry out aqueous solution polymerization or inverse suspension polymerization; And then preferred adopt be in above-mentioned or after state the peak temperature, polymerization time etc. of use amount, the polymerization temperature of concentration, the polymerization initiator of total mole %, the monomer component of acrylic acid and/or its salt in the scope.
When making the monomer solution polymerization, adopted and used the redox series initiators of radical polymerization initiator and reducing agent etc.Radical polymerization initiator for example has: persulfates such as potassium peroxydisulfate, ammonium persulfate, sodium peroxydisulfate; Hydroperoxides such as tertbutanol peroxide, hydrogen peroxide; 2,2 '-azo-compounds such as two (2-amidine propane) dihydrochlorides of azo; 2-hydroxyl-1-phenyl-propane-1-ketone; Benzoin methyl ether etc.Reducing agent for example is the L-ascorbic acid of these radical polymerization initiators decomposition of promotion etc.The use amount of polymerization initiator is generally 0.001～1 mole of % with respect to monomer, and then is 0.001～0.5 mole of %.
Utilizing said redox series initiators to carry out under the situation of polymerization, preferably with persulfate or peroxide and said reducing agent and usefulness.As reducing agent, for example can enumerate: (weight) sulfurous acid (salt) such as sodium sulfite, sodium hydrogensulfite; Reducing metals (salt) such as L-ascorbic acid (salt), ferrous salt; Amine etc.The use amount of these reducing agents is with respect to common preferred 0.0001～0.02 mole of % of monomer component.
In addition, also can not use polymerization initiator, but reaction system irradiation radioactive ray, electron beam, ultraviolet isoreactivity energy-ray are carried out polymerisation.In addition, also can and use radioactive ray, electron beam, ultraviolet isoreactivity energy-ray and polymerization initiator.
In addition; Through with after the methoxybenzene phenols (especially p methoxy phenol) stated; And then carry out polymerization in monomer solution when adding chelating agent to polymerization or the monomer solution in the polymerization process, just can further bring into play effect of the present invention, so preferred.
Can use inverse suspension polymerization, aqueous solution polymerization, spray polymerization or polymerization of fluid drops among the present invention, in order further to bring into play effect of the present invention, the preferred polymeric step is an aqueous solution polymerization.To aqueous solution polymerization, can be in advance in and acrylic acid, also can after polymerization, neutralize.For the water absorbent rate (CRC) that improves mutual exclusion relativeness, include the sectionalization step (following (1-7)) of the aqueous gel shaped polymer in polymerization process or after the polymerization with the water soluble composition.
(1-7) gel grain refined step
The aqueous gel shape cross-linked polymer that obtains through polymerization can directly carry out drying, but preferred grain refined of in polymerization process or after the polymerization, carrying out this aqueous gel shape cross-linked polymer.And, use gel crushing machine etc. to carry out grain refined as required, the weight average particle diameter (being decided by sieve classification) that preferably imposes after the grain refined is 0.1～3mm, and then is 0.5～2mm, makes its drying thereafter.The not special restriction of the shape of polyacrylic acid of the present invention (salt) water-absorbent resin for example can be processed graininess, form arbitrarily such as Powdered, laminar, fibrous.
Therefore, grain refined can be carried out through the whole bag of tricks, for example can illustration: adopt said kneader polymerization to carry out the grain refined under the situation of polymerization; Or, adopt belt polymerization or storage tank polymerization to carry out after the polymerization, from the screw type extruder of the loose structure aqueous gel shape cross-linked polymer of extruding and crush with arbitrary shape.When extruding crushing, the chelating agent through stating after adding with the form of the aqueous solution can further reduce change color.
Among the present invention, preferably, adds said aqueous gel shape cross-linked polymer inorganic reducing agent when being carried out grain refined.In gel grain refined step, mix through aqueous gel and inorganic reducing agent being mixed go forward side by side a step, can realize effect of the present invention in higher level ground.In addition, for gel grain refined step or polymerization procedure (in the way), if before drying steps, add inorganic reducing agent; Then consider the problem of foul smell; 3～15 weight % that moisture content in the water absorbing agent of the present invention is stated after preferably, in addition, in the manufacturing approach of water absorbing agent of the present invention; Preferably behind the drying steps and in surface-crosslinked step, the moisture content of polymer is controlled at 3～15 weight %.
If after inverse suspension polymerization forms graininess, adding inorganic reducing agent (and then chelating agent or alpha-hydroxy carboxylic acid compounds compound of stating after adding), inorganic reducing agent then only is blended on the surface of water-absorbing resins.With regard to effect of the present invention aspect, preferably, inorganic reducing agent or chelating agent optionally or alpha-hydroxy carboxylic acid compounds compound not only are blended on the surface of water-absorbent besin particles, also are mixed to inside.Therefore, preferably when the polymeric gel behind the aqueous solution polymerization (especially block gel or sheet gel) is carried out sectionalization, itself and said inorganic reducing agent etc. are mixed.
In addition, when carrying out grain refined and mixing (especially mixing), be fit to use kneader or screw type extruder (to claim again: meat grinder).Many machine series connection can be used, also can and use different devices such as kneader and meat grinders.The screw type extruder can use 1, also can use more than 2.
(1-8) drying steps
Drying steps in the manufacturing approach of particulate water-absorbing agent of the present invention is: to through polymerization procedure and aqueous gel, preferred particulates shape aqueous gel so that preferably by sieve classification fixed weight average particle diameter be the aqueous gel of 0.1～3mm, impose dry step.
As drying means; Can adopt heat drying, heated-air drying, drying under reduced pressure, fluidized bed drying, infrared drying, microwave drying, whizzer dry, with the azeotropic dehydration of hydrophobic organic solvent, use the high humidity drying of high-temperature vapor etc., a kind of the whole bag of tricks or more than 2 kinds.As optimal way, for example having with dew point is the contact drying of 40～100 ℃ of gases, and more preferably dew point is 50～90 ℃ a gas.If adopt heated-air drying, its wind speed (the dry object of spreading out with respect to level and vertically pass through wind speed) is 0.01～10 [m/sec] preferably, is more preferably the scope of 0.1～5 [m/sec].
In the present invention, the not special restriction of the baking temperature that is suitable for, the scope that for example is 50～300 ℃ is (below 100 ℃ the time; Preferably under reduced pressure carry out drying); Preferred 100～250 ℃, and then preferred 130～220 ℃, especially preferred 150～200 ℃ temperature range.Be generally 10～120 minutes drying time, more preferably 20～90 minutes, and then preferred 30～60 minutes.Drying time is during less than 10 minutes, because the variation that takes place on the inner polymer chain of water-absorbing resins is just less, so think and can't obtain to improve fully effect, therefore can't show the raising effect of various physical propertys sometimes.In addition, be more than 120 minutes the time drying time, can cause damage to water-absorbing resins, and the result is that the water soluble composition increases, and can not show the raising effect of various physical propertys sometimes.
Promptly; In the present invention; With regard to control metoxyphenol or adjustment moisture content, preferred following drying steps: under 100～250 ℃ of baking temperatures, the condition of 10～120 minutes drying times, the graininess aqueous gel being dried to moisture content is below the 20 weight %.And then preferably be in said or after state baking temperature, drying time, the moisture content in the scope.
In drying steps of the present invention, preferably will be dried to below the 20 weight % through the moisture content of the aqueous gel shape cross-linked polymer that said polymerization obtained, more preferably be dried to below the 15 weight %, especially preferably be dried to below the 10% weight %.At this; More than the preferred in regular turn 2 weight % of dried moisture content, more than the 3 weight %, more than the 4 weight %, more than the 5 weight %, more than the 6 weight %, more than the 7 weight %; Through making dried moisture content be in these more than lower limit, can suppress foul smell problem because of using reducing agent to cause.Under these scopes, moisture content is preferably 2～20 weight %, 3～15 weight % more preferably, and then be preferably 5～15 weight %, especially be preferably 7～15 weight %.In addition, can carry out (1-8) drying steps and following (1-10) surface-crosslinked step simultaneously, in addition, also can in drying steps, add surface crosslinking agent, then with side by side surface-crosslinked or after surface-crosslinked, drying reaches to said moisture content.
In the present invention,,, remaining monomer then takes place easily, and usability thereafter is relatively poor, even and if with chelating agent and inorganic reducing agent, if moisture content is higher, just can easy colorizing if find that moisture content is higher about the moisture content of the final water absorbing agent behind the drying steps.In addition, if moisture content is lower, then,, then produce the problem of foul smell sometimes if before dry, use reducing agent because of over-drying productivity or the physical property (for example, absorption speed) of can causing descends.In addition; In patent documentation 17 (No. 1645596 specification of European patent) or the patent documentation 15 (U.S. Patent application discloses No. 2005/0856604); Do not disclose p methoxy phenol or the water-insoluble microparticle that uses specified quantitative, do not disclose the importance of the specific moisture content (3～15 weight %, 4～14 weight %, 6～12 weight %, 7～11 weight %) of water absorbing agent yet.
The inventor finds, if before drying steps, add inorganic reducing agent, described foul smell problem takes place just.And the present invention has solved said problem through the control moisture content.This foul smell is the foul smell that simple reducing agent decomposes, not equal to be the compound foul smell of micro constitutent such as the aqueous gel after the polymerization, remaining monomer and reducing agent.The generation of inferring foul smell is because the moisture content of water-absorbing resins is controlled at the cause below the certain value, therefore learn drying steps of the present invention and after the moisture content stated in the surface-crosslinked step very important.In addition, if dried moisture content is too high, then sometimes can be in following pulverizing or hierarchical processing with the problem of productivity decline, so not good enough.
(1-9) pulverising step, classification step
Through dry and water-absorbing resins of the present invention can be according to its purpose and as required, and experience pulverizings, classification etc. are in order to control the step of particle diameter.About these methods, for example on the books in No. the 2004/69915th, International Publication.
Through the aqueous gel shape cross-linked polymer after the polymerization is dry, just can obtain dry polymer.Dry polymer can directly be processed dried powder (preferred solid constituent is more than the 80 weight %) and use, and also can after drying, adjust granularity as required in addition.For the surface-crosslinked processing of stating after the usefulness improves physical property, dried water-absorbing resins is preferably processed specified particle size.Granularity can wait suitably adjustment through polymerization, pulverizing, classification, granulation, micro mist recovery.
The weight average particle diameter (D50) of the water-absorbing resins (being expressed as " water-absorbing resins powder " among this specification embodiment) before surface-crosslinked is adjusted into 200～550 μ m; Preferably be adjusted into 250～500 μ m; More preferably be adjusted into 300～450 μ m, especially preferably be adjusted into 350～400 μ m.In addition, particle diameter is few more good more less than the particle of 150 μ m.The weight that the relatively dry polymer is all, particle diameter is adjusted into 0～5 weight % usually less than the part by weight of the particle of 150 μ m, preferably is adjusted into 0～3 weight %, especially preferably is adjusted into 0～1 weight %.And then it is good more that the above particle of particle diameter 850 μ m lacks more.With respect to all weight of dry polymer, the part by weight of the particle that particle diameter 850 μ m are above is adjusted into 0～5 weight % usually, preferably is adjusted into 0～3 weight %, especially preferably is adjusted into 0～1 weight %.The logstandard deviation of size distribution (σ ζ) is preferably 0.20～0.45, and more preferably 0.27～0.40, and then be preferably 0.25～0.37.Also preferred described granularity is applicable to water-absorbing resins and the water absorbing agent of end article after surface-crosslinked.Therefore, preferably after the surface-crosslinked step and/or after the interpolation step at chelating agent, inorganic reducing agent, additional as required classification step or crushing step.
(1-10) surface-crosslinked step
About the particulate water-absorbing agent that is obtained among the present invention, can process the water absorbing agent that is more suitable for being used for hygienic material through existing surface-crosslinked treatment step.Surface-crosslinked being meant, (the near surface: further form out the higher part of crosslink density common position) on the top layer of water-absorbing resins apart from the several 10 μ m in water-absorbing resins surface.The part that this crosslink density is higher can radical crosslinking, surface aggregate through carrying out be from the teeth outwards handled, is waited with the cross-linking reaction of surface crosslinking agent and form.
Surface crosslinking agent as adopting among the present invention for example has: have the surface crosslinking agent (preferably covalently bonding property surface crosslinking agent) that constitutes the function of ionic bonding or covalent bonding with the functional group of polyacrylic acid water-absorbent resin.As this surface crosslinking agent, but the various organic or inorganic crosslinking agents of illustration, but with regard to the viewpoint of physical property or usability, the crosslinking agent that preferred employing can react with carboxyl.But for example a kind below the illustration or the compound more than 2 kinds: with polyol compound, polynary glycidyl compound is the polynary epoxide of representative; The condensation product of polyamine compound or this polyamine compound and halogenated epoxide; Oxazoline compound; Monosubstituted oxazolyl ketonic compound, dioxazole ketonic compound or gather the oxazolone compound; Multivalent metal salt; The alkylene carbonate compound; Oxetane compound; Ring-type carbamide compound etc.
More specifically, illustrative compound in can enumerate United States Patent (USP) No. 6228930, No. the 6071976th, United States Patent (USP), No. the 6254990th, United States Patent (USP) etc.For example can enumerate: monoethylene glycol, diethylene glycol, triethylene glycol, TEG, polyethylene glycol, single propane diols, 1, ammediol, DPG, 2,3; 4-trimethyl-1,3-pentanediol, polypropylene glycol, glycerine, polyglycereol, 2-butene-1,4-glycol, 1; 4-butanediol, 1,3-butanediol, 1,5 pentanediol, 1; 6-hexylene glycol, 1, polyol compounds such as 2-cyclohexanedimethanol; Epoxide such as ethylene glycol diglycidylether, glycidol; Polyamine compounds such as ethylenediamine, Diethylenetriamine, three second tetramines, tetren, five second hexamines, polymine, polyamide polyamine; Halogenated epoxides such as chloropropylene oxide, epibromohydrin, Alpha-Methyl chloropropylene oxide; The condensation product of said polyamine compound and said halogenated epoxide; Oxazolone compounds such as 2-oxazolone; Alkylene carbonate compounds such as ethylene carbonate; Oxetane compound; Ring-type carbamide compounds such as 2-imidazolone etc., not special the qualification.
In these surface crosslinking agents, in order to improve AAP and SFC, suitable use is selected from the dehydration property crosslinking agent of polyol compound, oxazolone compound, alkylene carbonate compound as surface crosslinking agent.In addition, in order when surface-crosslinked or after surface-crosslinked, following moisture content to be controlled at 3～15 weight %, using with polynary glycidyl compound is good as the polynary epoxide of representative as surface crosslinking agent.
Though the use amount of surface crosslinking agent is different with used compound and their combination etc.; But with respect to water-absorbing resins powder 100 weight portions; The scope of preferred 0.001 weight portion of the use amount of surface crosslinking agent～10 weight portions, the more preferably scope of 0.01 weight portion～5 weight portions.In the present invention, but matching surface crosslinking agent and make water.At this moment, the water yield of use is with respect to water-absorbing resins powder 100 weight portions, preferred 0.5～20 weight portion, the more preferably scope of 0.5～10 weight portion.In addition, in the present invention, beyond dewatering, also can use hydrophilic organic solvent.
At this moment, the amount of employed hydrophilic organic solvent is 0～10 weight portion with respect to water-absorbing resins powder 100 weight portions, the scope of preferred 0～5 weight portion.In addition; When being mixed to cross-linking agent solution in the water-absorbing resins powder, also can not hinder under the prerequisite scope of effect of the present invention, coexistence is the inorganic microparticle of water-insoluble, the surfactant below 0～10 weight % for example; Preferred coexistence 0～5 weight %, 0～1 weight % more preferably coexists.Employed surfactant and use amount thereof have illustration in No. the 7473739th, United States Patent (USP).
As the mixing arrangement that supplies to mix said surface-crosslinked agent solution; Can use various mixers; Preferred high-speed stirred type mixer; Especially preferred high-speed stirred type continuous mixer, for example can illustration: commodity be called the mixer of Turbulizer (Japan's close Krona of (Hosokawa Micron) manufactured in thin river) or mixer (German sieve ground lattice (Loedige) manufactured) that commodity are called sieve ground lattice etc.
In the manufacturing approach of particulate water-absorbing agent of the present invention, surface treatment is the step of carrying out surface-crosslinked reaction, and surface-crosslinked reaction is in order to improve the crosslink density on water-absorbing resins surface.In order to obtain the required performance of particulate water-absorbing agent of the present invention, mixed the water-absorbing resins behind the surface crosslinking agent and preferably passed through heat treated, and carried out cooling processing thereafter as required.
The heating-up temperature of said heat treated (heat medium temperature) for example is 70～300 ℃, preferred 120～250 ℃, and more preferably 150～250 ℃, the scope of preferably 1 minute～2 hours heat time heating time.Heat treated can use common drying machine or heating furnace to carry out.At this; When adopting 150～250 ℃ to wait (carboxyl of water-absorbing resins) dehydration property surface crosslinking agent such as the surface-crosslinked and polyalcohol of high temperature, further make water-absorbing resins dry and carry out moisture content after surface-crosslinked have less than 3%, especially less than 1% tendency.
Especially when the manufacturing moisture content is the particulate water-absorbing agent of 3～15 weight %; Preferably, heating-up temperature (heat medium temperature and material temperature) heats in being 80～250 ℃ temperature range; More preferably 80～160 ℃ temperature range; And then preferred 80～120 ℃ temperature range, most preferably 80～100 ℃ temperature range.If heating-up temperature is less than 80 ℃, then the surface-crosslinked meeting of water-absorbing resins is insufficient, adds to depress water absorbent rate or saline solution water conservancy diversion rate can reduce.In order moisture content to be controlled at 3～15 weight %, preferably to use with polynary glycidyl compound and be used as surface crosslinking agent as the polynary epoxide of representative.In addition, if be higher than 250 ℃, then particulate water-absorbing agent can be painted, maybe can produce undesirable foul smell, so not good enough.In addition, the moisture content of water-absorbing resins is not only decided by heating-up temperature, also depends on pressure (decompression) or dew point, the output (treating capacity on the unit interval) etc. of heat time heating time, reaction unit, therefore suitably sets these conditions and gets final product.In addition, because the material temperature of water-absorbing resins is usually less than heating-up temperature,, heat and obtain the water absorbing agent of regulation moisture content thus so preferably material temperature is remained on below the boiling point of water.
These surface cross-linking treatment methods are in various european patent document such as No. the 0349240th, European patent, No. the 0605150th, European patent, No. the 0450923rd, European patent, No. the 0812873rd, European patent, No. the 0450924th, European patent, No. the 0668080th, European patent; Or in various Japanese documentations such as japanese kokai publication hei 7-242709 number, japanese kokai publication hei 7-224304 number; In the various american documentation literatures such as No. the 5409771st, United States Patent (USP), No. the 5597873rd, United States Patent (USP), No. the 5385983rd, United States Patent (USP), No. the 5610220th, United States Patent (USP), No. the 5633316th, United States Patent (USP), No. the 5674633rd, United States Patent (USP), No. the 5462972nd, United States Patent (USP); Also on the books in the various International Publication patent documentations such as No. the 99/42494th, International Publication, No. the 99/43720th, International Publication, No. the 99/42496th, International Publication, these surface-crosslinked methods also can be used in the present invention.In addition, in surface-crosslinked treatment step, also can after said cross-linking reaction, further add the water-soluble multivalent metal salts of this type such as aluminum sulfate aqueous solution.About this method, also on the books in No. the 2004/69915th, International Publication, No. the 2004/69293rd, International Publication etc., it is in the present invention available.
In addition; In order to control metoxyphenol; Also preferably carry out surface-crosslinked step among the present invention through following mode: to 100 weight portions of the absorbent resin powder behind the drying steps, blending surface crosslinking agent 0.001～10 weight portion, and 70～300 ℃ of following heat treated 1 minute～2 hours.Furthermore, employing be said or after the surface crosslinking agent stated and amount thereof, heating-up temperature, time.
In addition, also can add following polyvalent metal and/or cation property copolymer in surface-crosslinked or after surface-crosslinked.These polyvalent metals and/or cation property copolymer also can be used as the ionic bonding surface crosslinking agent, by with these polyvalent metals and/or cation property copolymer and said covalent bonding surface crosslinking agent and usefulness, can further improve permeability for liquids.
At this; When the manufacturing moisture content is 3～15 weight % particulate water-absorbing agents; Preferably 3 weight % are above in regular turn, 4 weight % above for the moisture content of the water-absorbing resins after surface-crosslinked, 5 weight % are above, 6 weight % are above, more than the 7 weight %; Through surface-crosslinked moisture content is controlled in these scopes; The foul smell that reducing agent caused that can suppress to use, especially for when the surface-crosslinked step or before it, adding inorganic reducing agent water absorbing agent, can suppress its foul smell.The result can further suppress the foul smell of the final water absorbing agent that obtains.For the scheme of when the surface-crosslinked step or before surface-crosslinked step, adding inorganic reducing agent, especially for before drying steps, so that the scheme of after polymerization, adding inorganic reducing agent before the drying steps, it is especially obvious that this foul smell suppresses effect.Therefore when the interpolation that relates to inorganic reducing agent, especially moisture content is controlled.In addition, as other schemes, if the moisture content when surface-crosslinked is less than 3 weight %, for example can be with 150～250 ℃ heat medium temperature, material temperature, adopt that high temperature is surface-crosslinked, dehydration property surface crosslinking agent wait carry out surface-crosslinked.In this surface-crosslinked scheme, with regard to the viewpoint that suppresses foul smell, more preferably after surface-crosslinked step, add inorganic reducing agent.
This foul smell is the foul smell that simple reducing agent decomposes; Not equal to be the compound foul smell of micro constitutents such as water-absorbing resins, its remaining monomer and reducing agent; The generation of inferring foul smell is owing to the moisture content with water-absorbing resins is controlled at the cause below the certain value, therefore learns that the moisture content in said drying steps of the present invention and the surface-crosslinked step is very important.In addition, in order to obtain to absorb multiplying power and the higher water absorbing agent of absorbent rate under pressure, the moisture content of the water-absorbing resins after surface-crosslinked is dropped in the above-mentioned scope.
And; When the manufacturing moisture content is the particulate water-absorbing agent of 3～15 weight %; Preferably under the moisture content that makes water-absorbing resins remains on the state of 3～15 weight %, carry out surface-crosslinked; More preferably under the state that remains on 4～14 weight %, carry out surface-crosslinkedly, and then preferably under the state that remains on 5～13 weight %, carry out surface-crosslinkedly, most preferably under the state that remains on 6～12 weight %, 7～11 weight %, carry out surface-crosslinked.If moisture content is more than the lower limit of said scope, then can avoid the absorption multiplying power of water-absorbing resins to descend significantly.If moisture content is below the upper limit of said scope (15 weight %), then can further improves coloring problem, and can suppress the usability deterioration of water-absorbing resins and the flowability decline of powder.
Can after surface-crosslinked, further carry out drying as required, also can add water, other additives are adjusted moisture content, its physical property.Can be after surface-crosslinked; Add the preferably inorganic microparticle of water-insoluble etc. of interpolation of the essential reducing agent that adds of institute, chelating agent and institute among the present invention; In addition, with respect to water-absorbing resins 100 weight portions, also can preferably add 0.001～20 weight portion; More preferably 0.01～10 weight portion, the antiseptic of especially preferred 0.1～5 weight portion, deodorant, polyvalent metal compounds etc. be used as additive.
(1-11) other steps
Except above-described scheme, also can set granulation step, micro mist as required and remove step, the set-up procedure (for example this specification embodiment 1-16) of moisture content, micro mist and utilize step etc. again.In addition, also can after the surface-crosslinked step of (1-10), set the interpolation step of chelating agent, inorganic reducing agent.Can suitably use during interpolation and adopt in said (1-10) surface-crosslinked step, or after state the various mixers that adopt in [8] granulation processing etc.
Particulate water-absorbing agent of the present invention is with the particulate water-absorbing agent of polyacrylic acid (salt) water-absorbent resin as principal component, it is characterized in that: contain chelating agent and inorganic reducing agent, and the content of this chelating agent is 0.001～0.5 weight %; More than one important document in (1)～(3) below satisfying:
(1) content of methoxybenzene phenols is 5～60ppm,
(2) contain the inorganic microparticle of water-insoluble,
(3) moisture content is 3～15 weight %.
Below, to [2] chelating agent, [3] inorganic reducing agent, [4] methoxybenzene phenols, and the inorganic microparticle of [5] water-insoluble describe.
[2] chelating agent
In order to solve problem, particulate water-absorbing agent of the present invention must contain chelating agent.With regard to the effect aspect, preferably with macromolecular compound or on-macromolecular compound as chelating agent of the present invention, preferred on-macromolecular compound.Particularly, be preferably selected from the compound of amino polybasic carboxylic acid, organic multicomponent phosphoric acid, inorganic multivariate phosphoric acid, amino polynary phosphoric acid.With regard to the effect aspect, the molecular weight of chelating agent preferably 100～5000 is more preferably 200～1000.If there is not chelating agent, then can become relatively poor water absorbing agent because of painted or deterioration.
At this, polynary being meant has a plurality of these functional groups in 1 molecule, preferably have 2～30, and then preferably has 3～20,4～10 these functional groups.In addition, these chelating agents are water-soluble chelator preferably, specifically refer in 100g (25 ℃) water solubilized 1g more than, and then the water-soluble chelator more than the solubilized 10g.
As said amino polybasic carboxylic acid; Can enumerate: imino group 2 acetate, ethoxy imido grpup 2 acetate, nitrogen base 3 acetate, nitrogen base 3 propionic acid, ethylenediamine 4 acetate, Diethylenetriamine 5 acetate, three second tetramines, 6 acetate, anti-form-1,2-diaminourea thiacyclohexane 4 acetate, N, two (2-ethoxy) glycine of N-, diamino-propanol 4 acetate, ethylenediamine 2 propionic acid, hydroxyethyl diamine 3 acetate, glycol ether diamines 4 acetate, diaminopropanes 4 acetate, N; N '-two (2-hydroxybenzyl) ethylenediamine-N; N '-2 acetate, 1,6-hexamethylene diamine base-N, N; N ', N '-4 acetate and those sour salt etc.
As said organic multicomponent phosphoric acid, can enumerate: nitrogen guanidine-acetic acid-two (methylene phosphinic acids), nitrogen base oxalic acid-(methylene phosphinic acids), nitrogen guanidine-acetic acid-β-propionic acid-methylene phosphonic acid, nitrogen base three (methylene phosphonic acid), 1 hydroxyethylidine diphosphonate etc.In addition, as said inorganic multivariate phosphoric acid, can enumerate: pyrophosphoric acid, tripolyphosphate and their salt etc.
And; As the polynary phosphoric acid of said amino; Can enumerate: ethylenediamine-N, N '-two (methylene phosphinic acids), ethylenediamine tetraacetic (methylene phosphinic acids), thiacyclohexane diamines four (methylene phosphonic acid), ethylenediamine-N, N '-oxalic acid-N; N '-two (methylene phosphonic acid), ethylenediamine-N, N '-two (methylene phosphonic acid), ethylenediamine tetraacetic (methylene phosphonic acid), polymethylene diamines four (methylene phosphonic acid), Diethylenetriamine five (methylene phosphonic acid), and those sour salt etc.
In addition, as the polynary phosphoric acid of most preferred amino among the present invention, can enumerate ethylenediamine tetraacetic (methylene phosphonic acid) or its salt etc.As salt, preferably monovalent salt for example has alkali metal salts such as sodium salt, sylvite and ammonium salt, amine salt.Especially particular certain cancers, sylvite.
In addition, in above compound of giving an example etc., with regard to preventing painted viewpoint, adopting amino carboxylic acid is that metal-chelator, amino polynary phosphoric acid are that metal-chelator and their salt are good.Especially the compound below adopting is good: Diethylenetriamine 5 acetate, three second tetramines, 6 acetate, anti-form-1,2-diaminourea thiacyclohexane 4 acetate, ethylenediamine 4 (methylene phosphinic acids), Diethylenetriamine five (methylene phosphonic acid), and their salt.Wherein, most preferably ethylenediamine tetraacetic (methylene phosphonic acid) or its salt.As salt, preferred monovalent salt for example has alkali metal salt such as sodium salt, sylvite and ammonium salt, amine salt.In addition, in these salt, especially particular certain cancers, sylvite.
The content of chelating agent is 0.001～0.5 weight % in the particulate water-absorbing agent of the present invention, preferred 0.001～0.1 weight %, more preferably 0.002～0.1 weight %, and then preferred 0.003～0.05 weight %, especially preferred 0.005～0.05 weight %.If the content of said chelating agent is less than 0.001 weight %, then particulate water-absorbing agent through the time painted can aggravation, cause this particulate water-absorbing agent through the time tone worsen, so not good enough.In addition, as the situation among the embodiment of said patent documentation 29 etc., find that if the content of said chelating agent surpasses 0.5 weight %, then the initial coloration of particulate water-absorbing agent can increase, and can cause the initial stage tone of particulate water-absorbing agent to worsen, therefore not good enough.In addition and since this particulate water-absorbing agent through the time tone situation of deterioration is also arranged, so not good enough.
In addition, " through the time painted " be meant the painted of under environment such as high temperature, the high humidity particulate water-absorbing agent after the long preservation." initial coloration " is meant the tone or the colourity of the particulate water-absorbing agent that has just made.
This chelating agent can add in wherein more than one the step of said (1-6) polymerization procedure, (1-7) gel grain refined step, (1-8) drying steps, (1-9) pulverising step/classification step, (1-10) surface-crosslinked step, (1-11) other steps.If (1-6) polymerization procedure can add chelating agent by the monomer before polymerization procedure during the adjusting stage, also can in polymerization, add chelating agent.It is the content in the water absorbing agent that obtains in fact that chelating agent waits the use amount in each manufacturing step at (1-6)～(1-11).Same with the quantitative approach of remaining monomer, water soluble composition, for the chelating agent in the water absorbing agent, also can utilize water or normal saline solution to come from water absorbing agent, to extract chelating agent, and wait suitably quantitatively with liquid chromatography or ion chromatography.
In addition, disclosed in the said patent documentation 29 (No. 2006/109882 book of International Publication) and used the acrylic acid ammonium salt to prevent method of colouring, or repeatedly to add the compound or the sulphur that contain phosphorus atoms be that reducing agent prevents method of colouring monomer.But patent documentation 29 does not only disclose specific moisture content of the present invention (3～15 weight %); Even contain the compound of phosphorus atoms or specific addition that sulphur is reducing agent (is 0.001～0.5 weight %; Preferred 0.001～0.1 weight %) do not disclose yet, disclosed the 1-hydroxy ethylene-1 of adding 1.0 weight %, 1-di 2 ethylhexyl phosphonic acid among the embodiment 5 of patent documentation 29; Disclosed among the embodiment 4 and used the same 1-hydroxy ethylene-1 that adds up to 2.0 weight %, 1-di 2 ethylhexyl phosphonic acid.The inventor finds, when using the chelating agent that surpasses 0.5 weight %, even and use inorganic reducing agent, also that kind shown in the comparative example 1-5 has as described later caused harmful effect to the water absorbing agent that obtained painted on the contrary.According to this discovery, the inventor has accomplished the present invention.
[3] inorganic reducing agent
Particulate water-absorbing agent of the present invention must contain inorganic reducing agent, and the water-soluble organic compounds that preferably contains the water-soluble inorganic compound with reducing inorganic element or have a reducing inorganic element is used as inorganic reducing agent.In addition, said " water-soluble " is meant: more than the water 100g solubilized 1g with respect to 25 ℃, and then more than the solubilized 5g, especially more than the solubilized 10g.If there is not chelating agent, then can become the remaining monomer that has, painted or water absorbing agent that the deterioration aspect is relatively poor.
Inorganic reducing agent among the present invention differentiates use with the reducing agent that is used as polymerization initiator in the said polymerization procedure.That is, inorganic reducing agent is meant the compound with reproducibility, and it has the reducing inorganic element and gets final product.Particularly, can enumerate compound with reducible sulfur atom or reproducibility phosphorus atoms, preferably contain the reducible sulfur atom compound, or contain the water soluble compound of reproducibility phosphorus atoms.Therefore, no matter be inorganic compound or organic compound, as long as have reducible sulfur atom or reproducibility phosphorus atoms, then all can it be regarded as inorganic reducing agent of the present invention.
Said inorganic reducing agent can be acid type, but the preferred salt type.As salt, more preferably 1 valency or multivalent metal salt, most preferably 1 valency salt.In these inorganic reducing agents, preferred back literary composition illustrative oxygen-containing reducing inorganic compound be the inorganic reducing agent of sulphur, phosphorus and oxygen bonding, wherein preferably containing oxygen is reducing inorganic salt.In addition, these inorganic reducing agents can be the inorganic atoms that on organic compounds such as alkyl, hydroxy alkyl, has reproducibility, preferably on organic compounds such as alkyl, hydroxy alkyl, have the sulphur atom of reproducibility or the inorganic reducing agent of phosphorus atoms.
In addition; With regard to the inorganic reducing agent that uses among the present invention with reducible sulfur atom or reproducibility phosphorus atoms; The oxidation number of the most stable sulphur atom is+6 (positive 6 valencys); The oxidation number of the most stable phosphorus atoms is+5 (positive 5 valencys); And each atom of oxidation number below the above-mentioned electrovalence has reproducibility usually, therefore use+4 valencys sulphur compound (for example sulphite, bisulfites, pyrosulfite) ,+sulphur compound (for example dithionite) of 3 valencys ,+sulphur compound (for example sulfoxylate) of divalent ,+phosphorus compound (for example hypophosphites) of 4 valencys ,+phosphorus compound (for example phosphite, pyrophosphite) of 3 valencys ,+phosphorus compound (for example hypophosphite) of 1 valency.In the inorganic compound of these reproducibilities, reducible sulfur atom or reproducibility phosphorus atoms can replace through organic matter.
Contain not special qualification of the inorganic compound as inorganic reducing agent of sulphur atom, for example can enumerate: sulphite such as sodium sulfite, potassium sulfite, calcium sulfite, zinc sulfite, ammonium sulfite; Bisulfites such as sodium hydrogensulfite, potassium bisulfite, calcium bisulfite, ammonium bisulfite; Pyrosulfites such as sodium pyrosulfite, potassium metabisulfite, ammonium pyrosulfite; Dithionite such as sodium dithionite, potassium hyposulfite, ammonium hyposulfite, calcium hyposulfite, zinc dithionite; Trithio sulfonate such as trithio potassium sulfonate, trithio sodium sulfonate; Four sulphur hydrochlorates such as four thiosulfonic acid potassium, four thiosulfonic acid sodium; Thiosulfates such as sodium thiosulfate, potassium thiosulfate, ATS (Ammonium thiosulphate); Nitrite such as natrium nitrosum, potassium nitrite, calcium nitrite, zinc nitrite etc.As the inorganic compound that contains phosphorus atoms, can enumerate inferior sodium phosphate etc.In these salt, preferred sulphite, bisulfites, pyrosulfite, dithionite, more preferably sodium sulfite, sodium hydrogensulfite, potassium metabisulfite, sodium dithionite.
In addition; The water-soluble organic compounds as inorganic reducing agent that contains sulphur atom does not have special qualification; For example can enumerate 2-hydroxyl-2-sulfinic acid root and close acetate, rongalite, FAS and thioglycolic acid three (2-carboxyethyl) phosphonium salt hydrochlorate (TCEP), tributylphosphine (TBP) etc., wherein preferred the 2-hydroxyl-2-sulfinic acid root closes acetate, 2-hydroxyl-2-sulfonate radical closes acetate and/or their salt.As preferred salt, be alkali metal salt and alkali salt, the salt of preferred Li, Na, K, especially particular certain cancers.2-hydroxyl-2-sulfinic acid root closes acetate (salt) and also can close acetate (salt) with 2-hydroxyl-2-sulfonate radical and be used in combination, and then also can and use with aforesaid inorganic compound.
Having the reducible sulfur atom because 2-hydroxyl-2-sulfinic acid root closes acetate with the form of sulfonite, therefore is preferred inorganic reducing agent among the present invention.Close acetate in order to obtain 2-hydroxyl-2-sulfinic acid root; BRUGGOLITE (R) FF7 that can use Bruggemann Chemical company (German Heilbron) to sell also can use the 2-hydroxyl-2-sulfinic acid root that contains 50～60 weight % to close the sodium sulfite (Na of acetate disodium salt, 30～35 weight % 2SO 3) and 2-hydroxyl-2-sulfonate radical of 10～15 weight % close BRUGGOLITE (R) FF6 of acetate disodium salt.
Contained preferred 0.01～1.0 weight % of inorganic reducing agent in the particulate water-absorbing agent of the present invention, more preferably 0.05～1.0 weight %, especially preferred 0.05～0.5 weight %.If the content of said inorganic reducing agent is more than the 0.01 weight %, then can suppress particulate water-absorbing agent through the time painted.In addition,, then can suppress the foul smell of particulate water-absorbing agent, especially can absorb the foul smell behind the aqueous solution to particulate water-absorbing agent effectively and suppress if the content of said inorganic reducing agent is below the 1.0 weight %.
In addition, inorganic reducing agent can add in wherein more than one the step of said (1-6) polymerization procedure, (1-7) gel grain refined step, (1-8) drying steps, (1-9) pulverising step/classification step, (1-10) surface-crosslinked step, (1-11) other steps (the interpolation step after surface-crosslinked etc.).For (1-6) polymerization procedure, inorganic reducing agent can be when polymerization begins, added, but reducing agent can be consumed usually, therefore preferably in polymerization, add, and then preferably add later at polymerization procedure.Also can be included in the manufacturing step amount of the reducing agent that especially in step, drying steps, is consumed in the addition.With regard to the amount of the inorganic reducing agent in the water absorbing agent that is obtained, if if especially add inorganic reducing agent later in surface-crosslinked back at drying steps, then the use amount in each manufacturing step is the content in the water absorbing agent of actual acquisition.For the chelating agent in the inorganic water absorbing agent that before drying steps, is added; Can be same with the quantitative approach of remaining monomer or water soluble composition; Utilize water or normal saline solution from water absorbing agent, to extract chelating agent, wait suitably quantitatively through liquid chromatography or ion chromatography then.(1-6)～(1-11) waiting use amount in each manufacturing step is the amount in the water absorbing agent of actual acquisition; Chelating agent in the water absorbing agent can with the quantitative approach of remaining monomer or water soluble composition likewise; Utilize water or normal saline solution from water absorbing agent, to extract chelating agent, wait suitably quantitatively through liquid chromatography or ion chromatography then.
With regard to the viewpoint that suppresses foul smell, inorganic reducing agent of the present invention preferably adds behind surface-crosslinked treatment step.If as patent documentation 5; Do not control specific moisture content of the present invention (3～15 weight %), and in surface-crosslinked treatment step or before it, add inorganic reducing agent, the particulate water-absorbing agent that is then obtained has foreign odor; Therefore not good enough; Especially work as the particulate water-absorbing agent that is obtained when having absorbed aqueous solution, can produce foreign odor, therefore not good enough.Infer that this foul smell is not merely the foul smell of inorganic reducing agent, still the foul smell of the secondary generation of institute in the surface-crosslinked step of pursuing high SFC, high AAP especially in surface-crosslinked step.
That is, the manufacturing approach 3 of the subordinate concept of water absorbing agent manufacturing approach of the present invention, it must satisfy said (c).The manufacturing approach of particulate water-absorbing agent of the present invention (3) is; With polyacrylic acid (salt) water-absorbent resin is the manufacturing approach (the 3rd manufacturing approach) of the particulate water-absorbing agent of principal component; It comprises with acrylic acid (salt) be the polymerization procedure of the monomer solution of principal component, drying steps, the surface-crosslinked step of the aqueous gel shape cross-linked polymer that gets through polymerization, and comprise interpolation step, and the interpolation step of inorganic reducing agent of 0.001～0.5 weight % chelating agent; When converting with respect to acrylic acid, said monomer contains the methoxybenzene phenols of 10～200ppm; Behind drying steps, and when surface-crosslinked step, the moisture content of polymer is controlled at 3～15 weight %; Preferably said inorganic reducing agent is added in the dry preceding aqueous gel shape cross-linked polymer.
[4] methoxybenzene phenols
Particulate water-absorbing agent of the present invention need contain the methoxybenzene phenols of 5～60ppm when not satisfying the important document of said (2) and (3).Even but arbitrary important document of said (2) and (3) is satisfied, also preferably contains the methoxybenzene phenols, more preferably contains the methoxybenzene phenols of 5～60ppm.
As the methoxybenzene phenols; Specifically can the illustration o-methoxyphenol, meta-methoxy phenol, p methoxy phenol; Or further have these substituent methoxybenzene phenols such as 1 or 2 above methyl, the tert-butyl group, hydroxyl on these phenol; Especially preferably use p methoxy phenol in the present invention, especially in said (1-6) polymerization procedure, use p methoxy phenol.
P methoxy phenol preferably is contained in the acrylic acid as the monomer principal component of polyacrylic acid (salt) water-absorbent resin that constitutes the present invention.The content of the methoxybenzene phenols in the particulate water-absorbing agent of the present invention (especially p methoxy phenol) is more preferably 5～50ppm, and then 6～50ppm preferably, and especially preferably 7～40ppm most preferably is 8～30ppm.In said (1-6) polymerization procedure; Through further (10～200ppm) state in the scope of putting down in writing in " (10-1) acrylic acid " project after being controlled at the content of methoxybenzene phenols; Just the gel stability in the time of further improving polymerization Control property and urine patience etc. and use, therefore preferred.
If the content of said methoxybenzene phenols is less than 5ppm; Even removed p methoxy phenol as polymerization inhibitor through purifying such as distillations; Then not only have want to begin polymerization begin before the danger of initiated polymerization; And be that the weatherability of the particulate water-absorbing agent of the present invention that obtains of main material also worsens with acrylic acid (salt), therefore not good enough.In addition,, can produce the uncontrolled problems of polymerisation such as polymerization delay, and the particulate water-absorbing agent of this scheme can take place painted, therefore not good enough if the content of said methoxybenzene phenols surpasses 60ppm.
Methoxybenzene phenols in the particulate water-absorbing agent of the present invention (5～60ppm) can adjust through following steps: making with the acrylic acid (salt) that contains 10～200ppm methoxybenzene phenols is that the monomer solution of principal component carries out said polymerization (described concentration, temperature, polymerization initiator etc.), make polymerization thereafter and aqueous gel shape cross-linked polymer under the condition of said preferable range, carry out drying (described temperature, time, wind speed, solid constituent etc.).As everyone knows; Usually use p methoxy phenol to be used as the polymerizing acrylic acid inhibitor with the amount of 200ppm; In addition; Also well-known, when the polymerization that imposes water-absorbing resins, can carry out distillation purifying (for example No. the 6388000th, United States Patent (USP)) or acrylates is handled (patent documentation 7) with activated carbon acrylic acid (143 ℃ of boiling points).In said distillation purifying, p methoxy phenol is removed from acrylic acid in fact, therefore can not have p methoxy phenol of the present invention.
In addition; Disclosed in the patent documentation 17 (No. 1645596 specification of European patent) contain the oxygen-containing reducing inorganic salts, amino carboxylic acid is the water absorbency resin composition of chelating agent and organic oxidation-resistant agent; As an example of organic oxidation-resistant agent, disclosed alkyl hydroxy methyl phenyl ethers anisole (claim 7 of patent documentation 17 is used 1 weight % in embodiment 6); But the alkyl hydroxy methyl phenyl ethers anisole is compared with p methoxy phenol, can not bring into play effect of sufficient.
And; Waiting with reducing agent of record prevents in the painted technology in said patent documentation 12 and the patent documentation 15～19; Do not disclose problem and the effect put down in writing in this specification; That is: and with chelating agent and inorganic reducing agent; And metoxyphenol (especially p methoxy phenol) is controlled at certain content (especially use metoxyphenol when the polymerization, and make metoxyphenol contain trace equably in water-absorbing resins inside).
Likewise,, then produce foul smell sometimes, therefore need note with the difference of the final moisture content after surface-crosslinked if as patent documentation 15 or embodiment 5, before dry, add inorganic reducing agent.Disclosed in the patent documentation 5 and satisfied the water-absorbing resins aggregation scheme that metoxyphenol is 10～160ppm; But comprise and disclose the patent documentation 10,11 that p methoxy phenol is arranged, each patent documentation do not disclose chelating agent and reducing agent in this specification and with scheme and preferred final moisture content.And; Though disclosed in these patent documentations and when polymerization, used p methoxy phenol; Can not be consumed when polymerization or when dry but disclose p methoxy phenol yet, not disclose control method of the present invention yet, therefore not disclose the amount of the p methoxy phenol in the gained end article.In addition; At non-patent literature 1 (The Modern Super Aborbent Polymer Technology; 1998) 41 page tables 5,2 in, put down in writing the remaining p methoxy phenol (MEHQ) in the water-absorbing resins that comes from 8 manufacturing site location A～H; Also having disclosed MEHQ is the water-absorbing resins of 16～151ppm, but does not also disclose of the present invention to the specific MEHQ (scheme of 5～60ppm) use chelating agents and inorganic reducing agent in the non-patent literature 1.
[5] the inorganic microparticle of water-insoluble
When particulate water-absorbing agent of the present invention did not satisfy the important document of said (1) and (3), particulate water-absorbing agent then of the present invention was the equal of to contain the inorganic microparticle of water-insoluble.And when having satisfied wherein certain important document of said (1) and (3), with regard to the viewpoint of flowability etc., preferably contain the inorganic microparticle of water-insoluble, especially the inorganic microparticle of water-insoluble of white when improving permeability for liquids (SFC) and moisture absorption.At this, through adding the inorganic microparticle of water-insoluble of white, can further improve the white effect of the water-absorbing resins that is obtained, it can improve the gel strength of water-absorbing resins, is good choosing therefore.Do not have in patent documentation 15～17 grades to disclose the p methoxy phenol of trace and the inorganic microparticle of water-insoluble of white etc. are carried out and the scheme of usefulness.At this; The whiteness of the inorganic microparticle of water-insoluble with L, a, b and count respectively more than 70, ± 5 with interior, 7 ± 10 with interior scope; Preferably be respectively more than 80, ± 3 with interior, ± 7 in; And then preferably be respectively more than 90, ± 2 with interior, ± 5 in, can use with mix before water-absorbing resins compare the insoluble inorganic microparticle of whiter (preferred L is more than 5 and then more than 7).Especially if the said moisture content of water absorbing agent is dropped in 3～15 weight %, and then drop in the said scope, then in order to solve problem of the present invention, preferred and with the inorganic microparticle of water-insoluble.
The inorganic microparticle of said water-insoluble preferably, the average grain diameter that records through the Ku Erte counting method be 0.001～200 μ m, be more preferably 0.005～50 μ m's and then the microparticle of 0.01～10 μ m preferably.The preferred hydrophilic microparticle for example can be enumerated: metal oxides such as silica (silica) or titanium oxide, contain zinc and silicon or contain zinc and silicic acid (salt) such as the compound hydrous oxide of aluminium No. the 2005/010102nd, International Publication (for example in illustration is arranged), natural zeolite or synthetic zeolite, kaolin, talcum powder, clay (clay), bentonite, calcium phosphate, barium phosphate, silicic acid or its salt, clay, diatomite, silica gel, zeolite, bentonite, hydroxyl phosphorus lime, hydrotalcite, vermiculite, perlite, Aesop Lai Te (trade name), atlapulgite, quartz sand, quartzite, strontium ore, fluorite, alumina etc.Wherein more preferably silica and silicic acid (salt), more preferably silica and silicic acid (salt).
Said silica is not special to be limited, the aerosil of the amorphous that preferably makes with dry process.Be called quartzy silica etc. owing to possibly cause the problem on the health, so not good enough.
The scope of preferred 0.05～1.0 weight % of content of the contained inorganic microparticle of water-insoluble in the particulate water-absorbing agent of the present invention, the scope of more preferably 0.05～0.8 weight %, and then preferred 0.05～0.7 weight %, especially preferred 0.1～0.5 weight %.If the content of the inorganic microparticle of water-insoluble is more than the 0.05 weight %, then can suppress the deterioration of the urine patience of particulate water-absorbing agent.If the content of the inorganic microparticle of water-insoluble is below the 1.0 weight %, then can suppress the decline that adding of particulate water-absorbing agent depress water absorbent rate.
In the water-absorbing resins of said [1],, preferably also contain following [6] alpha-hydroxy carboxylic acid compounds compound, [7] multivalent metal salt and/or cation property copolymer except containing [2] chelating agent～inorganic microparticle of [5] water-insoluble.And can also carry out [8] granulation.
[6] alpha-hydroxy carboxylic acid compounds compound
About particulate water-absorbing agent of the present invention; Just further prevent painted or prevent with regard to the deterioration viewpoints such as (weatherability, urine patiences); Except containing said reducible sulfur compound (for example 2-hydroxyl-2-sulfinic acid root closes acetate); Preferably also contain the alpha-hydroxy carboxylic acid compounds compound, be more preferably irreducibility alpha-hydroxy carboxylic acid compounds compound.At this, irreducibility alpha-hydroxy carboxylic acid compounds compound is meant do not have the reducing inorganic element hydroxy carboxylic acid compound of (for example reducible sulfur, sulfonite etc.).Especially if will satisfy high AAP or high SFC; Maybe to contain multivalent metal salt and/or polyamine polymer, then, preferably contain the alpha-hydroxy carboxylic acid compounds compound from preventing painted and preventing the viewpoint of deterioration etc.; And preferably in surface-crosslinked step, and even mixing thereafter.
The alpha-hydroxy carboxylic acid compounds compound that can adopt among the present invention is meant carboxylic acid or its salt that in molecule, has hydroxyl concurrently, just on the α position, has the hydroxy carboxylic acid compound of hydroxyl.The alpha-hydroxy carboxylic acid compounds compound is on-macromolecular alpha-hydroxy carboxylic acid compounds class preferably, and from adding the viewpoint of easy property, additive effect, its molecular weight preferably 40～2000 is more preferably 60～1000,100～500 scope especially preferably, and be preferably water-soluble.As this alpha-hydroxy carboxylic acid compounds compound, can enumerate: glycolic, tartaric acid, lactic acid (salt), citric acid (salt), malic acid (salt), isocitric acid (salt), glyceric acid (salt), gather Alpha-hydroxy acrylic acid (salt) etc.Wherein preferred lactic acid (salt), malic acid (salt), more preferably lactic acid (salt).
The salt of alpha-hydroxy carboxylic acid compounds is not special to be limited.As its salt, be to use monovalent salt or multivalent salts, preferred monovalent salt～trivalent salt, concrete particular certain cancers, sylvite, calcium salt, magnesium salts, aluminium salt, more preferably sodium salt.In addition, the acidic group of alpha-hydroxy carboxylic acid compounds can 100% the displacement salify, also can partly replace.
About these alpha-hydroxy carboxylic acid compounds compounds, from the viewpoint of cost performance, its content in particulate water-absorbing agent is the scope of 0.05～1.0 weight % preferably, more preferably 0.05～0.5 weight %, and then the scope of preferred 0.1～0.5 weight %.In addition, through being that the particulate water-absorbing agent of the present invention of the metoxyphenol, chelating agent and the inorganic reducing agent that contain particular range further contains the alpha-hydroxy carboxylic acid compounds compound, can further improve said effect of the present invention.
[7] multivalent metal salt and/or cation property copolymer
About particulate water-absorbing agent of the present invention, just improve absorption speed (Vortex), when improving permeability for liquids (SFC) and moisture absorption with regard to the viewpoint of flowability etc., preferably also contain multivalent metal salt and/or cation property copolymer.
Said multivalent metal salt is the acylate or the inorganic acid salt of polyvalent metal, the multivalent metal salt of preferred aluminium, zirconium, iron, titanium, calcium, magnesium, zinc etc.Multivalent metal salt both can be water-soluble, also can be water-insoluble all, but preferred water dissolubility multivalent metal salt.Can use in 25 ℃ water more than the solubilized 2 weight %, and then the above water-soluble multivalent metal salt of solubilized 5 weight %.Particularly, but illustration for example: inorganic acid salts such as aluminium chloride, polyaluminium chloride, aluminum sulfate, aluminum nitrate, two aluminum potassium sulfate, two aluminum sodium sulfate, alum, alum, aluminum sodium sulfate, sodium aluminate, calcium chloride, calcium nitrate, magnesium chloride, magnesium sulfate, magnesium nitrate, zinc chloride, zinc sulfate, zinc nitrate, zirconium chloride, zirconium sulfate, zirconium nitrate; Acylates such as the lactate of these polyvalent metals, acetate.
In addition, with regard to waiting with regard to the dissolubility of absorption liquid, preferably use the salt with crystallization water of above-mentioned example with urine.Especially preferred aluminium compound; Wherein preferred aluminium chloride, polyaluminium chloride, aluminum sulfate, aluminum nitrate, two aluminum potassium sulfate, two aluminum sodium sulfate, alum, alum, aluminum sodium sulfate, sodium aluminate; Especially preferably sulfuric acid aluminium, optimum uses the powder of water-containing crystals such as 18 hydrazine aluminum sulfates, 14～18 hydrazine aluminum sulfates.These compounds can only use a kind, and also two or more kinds may be used.
Said cation property copolymer is to have amino cation property copolymer, and is water-soluble cationic property polymer, preferably can in 25 ℃ water, dissolve more than the 2 weight % and then the water-soluble polymer more than the solubilized 5 weight %.For example preferred: polymine etc. gather alkylene imines, polyether polyamine, polyetheramine, polyvinylamine, gather alkylamine, PAH, polydiene propyl group amine, gather (N-alkyl allyl amine), monoene propyl group amine-diallylamine copolymer, N-alkyl allyl amine-monoene propyl group amine copolymer thing, monoene propyl group amine-dialkyldiallyl ammonium salt copolymer, diallylamine-dialkyldiallyl ammonium salt copolymer, polyethylene polyamines, polypropylene polyamines, gather amidine etc.; The salt of these polymer.In addition, more preferably enumerate the modified cation property polymer of record in No. the 2009/041727th, the International Publication.
The weight average molecular weight of cation property copolymer is preferred more than 5000, more preferably more than 10000, so that preferred more than 30000.If weight average molecular weight less than 5000, then has the worry that can't obtain to expect effect.In addition, the upper limit of the weight average molecular weight of said cation property copolymer is not special to be limited, but preferred below 1,000,000, more preferably below 500,000.Because the weight average molecular weight of said cationic macromolecular compound is below 1,000,000, thus viscosity reduction, usability or and to close performance more excellent, be good choosing therefore.In addition, weight average molecular weight can utilize known method such as GPC, viscosimetric analysis, static light scattering to measure.
It is surface-crosslinked that the utilization polyvalent metal is implemented, No. the 2007/121037th, International Publication, No. the 2008/09843rd, International Publication, No. the 2008/09842nd, International Publication, No. the 7157141st, United States Patent (USP), No. the 6605673rd, United States Patent (USP), No. the 6620889th, United States Patent (USP), U.S. Patent application disclose No. 2005/0288182, U.S. Patent application disclose No. 2005/0070671, U.S. Patent application disclose No. 2007/0106013, U.S. Patent application discloses in No. 2006/0073969 that announcement is arranged.In addition, except said organic surface crosslinking agent, also can be simultaneously or to use polyamine polymer, especially weight average molecular weight in addition be that about 5000～1,000,000 polyamine polymer improves permeability for liquids etc.
Employed polyamine polymer is for example having illustration in No. the 7098284th, United States Patent (USP), No. the 2006/082188th, International Publication, No. the 2006/082189th, International Publication, No. the 2006/082197th, International Publication, No. the 2006/111402nd, International Publication, No. the 2006/111403rd, International Publication, No. the 2006/111404th, the International Publication etc.
The contained multivalent metal salt and/or the use amount of cation property copolymer are 0～5 weight portion with respect to particulate water-absorbing agent 100 weight portions in the particulate water-absorbing agent of the present invention, preferred 0.001～3 weight portion, the more preferably scope of 0.01～2 weight portion.If the content of multivalent metal salt and/or cation property copolymer is more than 5 weight portions, then absorbent properties, especially water absorbent rate obviously descend sometimes, and cause sometimes painted, so not good enough.
[8] granulation
Particulate water-absorbing agent of the present invention is preferably the granulation thing.Through adopting the granulation thing, amount of dust contained in the particulate water-absorbing agent can reduce.
In order to obtain particulate water-absorbing agent of the present invention, preferably in polymerization process or after polymerization, carry out granulation.Through granulation, can obtain absorption speed or granularity more excellent, be suitable for the practical water absorbing agent of paper nappy that is.
At this, granulation is meant that a plurality of granular water-absorbing resins are combined into 1 bigger graininess, as long as final formation combines particle; In conjunction with the time both can be aqueous gel, also can be dry thing, also can be monomer; In conjunction with being a contact between particle, can be the face contact.Between particle the interface can be arranged, with intergranular combination situation, but also complete obiteration of interface.But, preferably has the granulation thing at interface from the aspect of absorption speed.
Water-absorbing resins before the granulation of using among the present invention can be merely (particle diameter is less than 150 μ m's) micro mist, also can be micro mist and have the mixture greater than the size particles of micro mist.The preferred weight average grain diameter of the water-absorbing resins before the granulation is below the 500 μ m, is 400 μ m when following, can improve performances such as absorption speed or hollow billet absorption multiplying power, so more preferably.Granulation of the present invention is meant: a plurality of water-absorbent besin particles bonding and, combine afterwards to have between particle the water-absorbent besin particles at no interface between water-absorbent besin particles or the particle at interface.Usually, also can come regulation granulation requirement according to the increase (for example 1.01～10 times) of weight average particle diameter and/or the minimizing of micro mist (for example 150 μ m sieve the minimizing that thing and then 106 μ m sieved thing).
In addition, in the water-absorbing resins before granulation, with respect to this water-absorbing resins, particle diameter, is more preferably more than the 30 weight % preferably more than the 10 weight % less than the ratio of the particle of 300 μ m, and then preferably more than the 50 weight %.Water-absorbing resins with this particle diameter can use inverse suspension polymerization (especially 2 sections polymerizations) to obtain; In addition can to through aqueous solution polymerization and water-absorbing resins impose pulverizing; Perhaps, adjust the granularity that obtains good choosing through the sieving of these water-absorbing resins.In addition; Can use water-absorbing resins fine powder to the following particle diameter of 300 μ m to impose the water-absorbing resins after granulation, the granularity adjustment, also can use the unsetting broken shape primary particle partially mixed fine powder granulation thing after pulverizing and the water-absorbing resins that obtains.If the partially mixed granulation thing that water-absorbing resins is arranged then can obtain the more excellent water absorbency resin compositions of the present invention of absorption characteristic such as absorption speed, hollow billet absorption multiplying power.The combined amount of fine powder granulation thing preferably more than the 5 weight %, is more preferably more than the 10 weight %, and then preferably more than the 15 weight %.
As prilling process,, a plurality of aggregated particles form bigger particle as long as combining, the not special restriction of its method.Can adopt: utilize the granulation of anti-phase suspension, promptly utilize the aggegation (No. the 0695762nd, European patent, No. the 4732968th, United States Patent (USP)) in the reversed-phase polymerization; Or, 2 sections polymerizations (No. the 0807646th, European patent); Or, after polymerization, add the anti-phase granulation (No. the 4732968th, United States Patent (USP)) of inert inorganic matter.Through granulation, can obtain to be more suitable for the water absorbing agent that paper nappy is made in practicality.The electron micrograph of representational granulation thing is shown in Fig. 3.
In addition, about the prilling process beyond the inverse suspension polymerization,, can use the known technology of micro mist regeneration preparation method as micro mist granulation thing in order to obtain particulate water-absorbing agent of the present invention.
For example can use: warm water is mixed with the micro mist of water-absorbing resins, and carry out dry method (No. the 6228930th, United States Patent (USP)); The micro mist of water-absorbing resins is mixed with monomer solution, and carry out the method (No. the 5264495th, United States Patent (USP)) of polymerization; Micro mist to water-absorbing resins adds water, and more than particular surface pressure, carries out process for granulating (No. the 844270th, European patent); The micro mist that makes water-absorbing resins is fully moistening and form amorphous gel, and carries out the method (No. the 4950692nd, United States Patent (USP)) of drying and pulverizing; Make micro mist and polymeric gel method of mixing (No. the 5478879th, United States Patent (USP)) of water-absorbing resins etc.Preferred use the above-mentioned method that warm water is mixed with the micro mist of water-absorbing resins and carry out drying.In addition, particle diameter is directly to represent with the eyelet of classifying screen.Make water as adhesive during granulation, also can contain said chelating agent, reducing inorganic thing etc. in the water.
In addition, after said surface-crosslinked processing, comprise granulation step, that is: add the aqueous solution body and make moisture content be in 1～10 weight %, heat keeping under the state of this moisture content then, and optionally carry out whole grain.Adjust the powder of specified particle size thus.The aqueous solution body that is added can be merely water, or also can contain chelating agent of the present invention and inorganic reducing agent, or contains plant component, antiseptic, water soluble polymer, inorganic salts etc.About the content of these materials, their concentration of aqueous solution is 0.001～50 weight %, and then 0.001～30 weight % preferably, most preferably is the scope of 0.01～10 weight %.In granulation of the present invention, the preferred employing is mixed into the method in the water-absorbing resins with aqueous solution spray body or dropping, more preferably adopts spray-on process.About the size of spray droplet, the average grain diameter of drop is preferably in the scope of 0.1～300 μ m, more preferably in the scope of 0.1～200 μ m.Used prilling granulator during as granulation, the preferred device that adopts with big mixing force.
Particularly, can illustration agitating type comminution granulation, roll type comminution granulation, compression-type comminution granulation and fluidized bed prilling method etc., utilize any method can preferably implement granulation.Wherein, from aspects such as simplicities, more preferably agitating type comminution granulation.When implementing these methods, need to utilize steam to supply with moisture, and device in addition and operating condition etc., be what can adopt with before known identical technology.Among the present invention; Owing to be through carrying out moisture and supply with supplying with steam in installing, therefore employed comparatively ideal device is to possess the nozzle that can inject steam etc., and seal is higher; Can adjust internal pressure, thus the device that the supply of steam can be carried out smoothly.
For example, if utilize the agitating type comminution granulation to implement granulation, then institute is employable has continous way and a batch agitating device, and continous way and batch agitating device have vertical and horizontal respectively again.As vertical continous way agitating device, can illustration: Spiralpin Mixer (Pacific Ocean machine worker manufactured), Flow Jet Mixer and Schugi Agglomeration Systems (powder grinds Bao Taisi (Funken Powtechs) manufactured) etc.As horizontal continous way agitating device, but illustration Annular Layer Mixer (Draiswerke manufactured) and biaxial rneader (List manufactured) etc.
As vertical batch agitating device, but illustration Henschel mixer (Henschel Mixer) (Mitsui mine manufactured) and Turbo-Sphere Mixer (Moritz manufactured) etc.As horizontal batch agitating device, but illustration sieve ground lattice mixer (sieve ground lattice manufactured), Multi-flux Mixer (rules and forms gram (Gericke) manufactured) and colter mixer (Ploughshare Mixer) (Pacific Ocean machine worker manufactured) etc.
As said prilling granulator, and then preference such as cylinder type mixer, double-walled circular cone mixer, high-speed stirred type mixer, V-shape mixer, banding pattern mixer, screw type mixer, double-arm kneader, crush type kneader, rotary mixer, airflow mixer, turbulence type mixer (Turbulizer), batch Luo Dige mixer, continous way Luo Dige mixer etc.
In addition, if after surface-crosslinked, carry out granulation, then preferably after having mixed the aqueous solution body, under the state that keeps moisture content, carry out heat treated.In this step, chelating agent and/or inorganic reducing agent are added also preferred chelating agent and/or the inorganic reducing agent of in granulation, adding with the form of the aqueous solution.Usually, if in water-absorbing resins, add water, then can produce adherence, if under the state that keeps moisture content, heat, then adherence can disappear at short notice, and the flowability of recovering powder, therefore can make manufacture process simplification, short timeization.
In addition, among the present invention this heating steps is called cure step.With regard to the viewpoint of granulation rate, granulation intensity; Heat treated is under the state that moisture content (following 3 hours loss on drying is stipulated according to 180 ℃) is remained 1～10 weight %, to heat; More preferably remain 2～8 weight %, and then preferably remain 2.5～6 weight %.During heating, use heating agents such as hot blast.Heating-up temperature (heat medium temperature or material temperature) is preferably in 40～120 ℃ scope, more preferably in 50～100 ℃ scope.Heat time heating time is preferably in 1 minute～2 hours scope.The preferable combination example of heating-up temperature and heat time heating time is: heated 0.1～1.5 hour down at 60 ℃; Heated 0.1～1 hour down at 100 ℃.
[9] particulate water-absorbing agent
Particulate water-absorbing agent of the present invention is to be the particulate water-absorbing agent of principal component with polyacrylic acid (salt) water-absorbent resin, and it is characterized in that: contain chelating agent and inorganic reducing agent, the content of this chelating agent is 0.001～0.5 weight %; Satisfy the more than one important document in following constitutive requirements (1)～(3),
(1) content of methoxybenzene phenols is 5～60ppm,
(2) contain the inorganic microparticle of water-insoluble,
(3) moisture content is 3～15 weight %.
Promptly; About satisfying the water absorbing agent of (1); The of the present invention novel water absorbing agent of stating among the embodiment after having to be disclosed (the 1st water absorbing agent), it is with the particulate water-absorbing agent of polyacrylic acid (salt) water-absorbent resin as principal component, it is characterized in that: contain chelating agent and inorganic reducing agent; The content of this chelating agent is 0.001～0.5 weight %, and the content of methoxybenzene phenols (especially p methoxy phenol) is 5～60ppm.After state the novel water absorbing agent of the present invention that discloses among the embodiment optimal technical scheme be: no absorbent rate under pressure (CRC) is more than 25 [g/g], adds that to depress water absorbent rate (AAP4.83kPa) be more than 20 [g/g], and saline solution water conservancy diversion property (SFC) is 30 [* 10 -7Cm 3Sg -1] more than.The preferred absorption speed (FSR) of this water absorbing agent is the above high absorption speed of 0.2 [g/g/sec], and the granularity stated after satisfying of this water absorbing agent.In addition, said water absorbing agent preferably also contains the alpha-hydroxy carboxylic acid compounds compound.In addition, also contain multivalent metal salt and/or cation property copolymer.These water absorbing agents do not have initial coloration and through the time painted and be white; And permeability for liquids (SFC) or absorbent rate under pressure (AAP) are higher; Even if therefore be used in the less high concentration diaper of paper pulp; Also have high liquid diffusivity and ooze (Re-wet) property, and do not have the coloring problem that causes by water absorbing agent, thereby good paper nappy can be provided with low contrary.
In addition; About satisfying the water absorbing agent of said (2); State the of the present invention novel water absorbing agent (the 2nd water absorbing agent) that discloses among the embodiment after having, it is with the particulate water-absorbing agent of polyacrylic acid (salt) water-absorbent resin as principal component, it is characterized in that: contain chelating agent and inorganic reducing agent; The content of this chelating agent is 0.001～0.5 weight %, and contains the inorganic microparticle of water-insoluble.Whether contain methoxybenzene phenols (especially p methoxy phenol) in this water absorbing agent for any; Also can contain 0～200ppm; But likewise be the scope of 5～60ppm preferably, can further improve weatherability and painted thus with said (1) and novel water absorbing agent of the present invention (the 1st water absorbing agent).The moisture content of novel water absorbing agent of the present invention (the 2nd water absorbing agent) can be same with the 1st water absorbing agent, less than 3 weight %.But preferably be in the scope of 3～15 weight % of (3).After state the novel water absorbing agent of the present invention that announcement is also arranged among the embodiment preferred version be: no absorbent rate under pressure (CRC) is more than 25 [g/g], adds that to depress water absorbent rate (AAP2.0kPa) be more than 25 [g/g], and absorption speed (Vortex) is below 60 seconds.
In addition; About satisfying the water absorbing agent of said (3); State illustrative novel water absorbing agent of the present invention (the 3rd water absorbing agent) among the embodiment after having, it is with the particulate water-absorbing agent of polyacrylic acid (salt) water-absorbent resin as principal component, it is characterized in that: contain chelating agent and inorganic reducing agent; The content of this chelating agent is 0.001～0.5 weight %, and moisture content is 3～15 weight %.Whether contain methoxybenzene phenols (especially p methoxy phenol) in this water absorbing agent for any; Also can contain 0～200ppm; But likewise be the scope of 5～60ppm preferably, can further improve weatherability and painted thus with said (1) and novel water absorbing agent of the present invention (the 1st water absorbing agent).Novel water absorbing agent of the present invention (the 3rd water absorbing agent) preferably likewise contains the inorganic microparticle of water-insoluble with said (1) and novel water absorbing agent of the present invention (the 1st water absorbing agent), can further improve urine patience like this.After state the novel water absorbing agent of the present invention that announcement is also arranged among the embodiment preferred version be: no absorbent rate under pressure (CRC) is more than 25 [g/g], adds that to depress water absorbent rate (AAP2.0kPa) be more than 25 [g/g], and remaining monomer is below the 500ppm.This water absorbing agent preferably also contains the alpha-hydroxy carboxylic acid compounds compound.In addition, also contain multivalent metal salt and/or cation property copolymer.
These novel water absorbing agents of the present invention (especially the 1st water absorbing agent and then the 2nd, 3 water absorbing agents) preferably contain: multivalent metal salt shown in the alpha-hydroxy carboxylic acid compounds (salt) shown in above-mentioned " [6] alpha-hydroxy carboxylic acid compounds compound " project and/or above-mentioned " [7] multivalent metal salt and/or cation property copolymer " project and/or cation property copolymer etc.Polyacrylic acid (salt) water-absorbent resin shown in these compounds and above-mentioned " [1] polyacrylic acid (salt) water-absorbent resin " column is included in the novel water absorbing agent of the present invention integratedly.
In addition; Particulate water-absorbing agent of the present invention is owing to will preferably be used in the high concentration diaper of white; Therefore permeability for liquids (SFC), the absorbent rate under pressure (AAP) in illustrative each physical property of back literary composition is very important, and then absorption speed, remaining amount of monomer are also very important.Any important document below in detail preferred particulate water-absorbing agent of the present invention satisfies: add that to depress water absorbent rate (AAP) be more than 20 [g/g]; Saline solution water conservancy diversion property (SFC) is 30 [* 10 -7Cm 3Sg -1] more than; Absorption speed (Vortex) is below 60 seconds; Remaining monomer is below the 500ppm.
The good scope of selecting of these physical propertys is following.
No absorbent rate under pressure (CRC) is more than 25 [g/g], adds that to depress water absorbent rate (AAP4.83kPa) be more than 20 [g/g], and saline solution water conservancy diversion property (SFC) is 30 [* 10 -7Cm 3Sg -1] more than.And then no absorbent rate under pressure (CRC) is more than 25 [g/g], adds that to depress water absorbent rate (AAP2.0kPa) be more than 25 [g/g], and absorption speed (Vortex) is below 60 seconds.Said water absorbing agent further satisfies following item.
(a)Fe
With regard to preventing its painted viewpoint, the Fe that particulate water-absorbing agent of the present invention contains is 1ppm (Fe preferably 2O 3Scaled value) below, and then preferably below the 0.1ppm, especially preferably below the 0.02ppm.About the control of Fe amount, can especially carry out purifying suitably to the amount of the Fe in the raw material of water-absorbing resins to the alkali that is used for neutralizing, for example remove NaOH, Na 2CO 3In Fe, control Fe amount thus.Can carry out the mensuration of Fe amount to raw material, also can carry out the mensuration of Fe amount final water absorbing agent.
In addition, " Fe 2O 3Scaled value " be a kind of compound (Fe with fe or iron content 2O 3Or its molysite, iron hydroxide, iron complex etc.) in the Fe absolute magnitude, the representational iron compound Fe of apparatus 2O 3The mode that (molecular weight 159.7) expresses." Fe 2O 3Scaled value " refer to the balance-element of the Fe weight after all oxidized, Fe becomes the component all can be according to molecular weight (Fe 2O 3In Fe), calculate with formula " 55.85 * 2/159.7 ".
Promptly; Iron is mainly from the alkali that is used to neutralize in the particulate water-absorbing agent of the present invention, and the iron (Fe) that preferred particulate water-absorbing agent of the present invention contains is for below the 2ppm, more preferably below the 1.5ppm; And then below the preferred 1ppm; Especially below the preferred 0.5ppm, lower limit is 0.001ppm preferably, is more preferably 0.01ppm.
For example if use Fe as 10ppm (if with Fe 2O 3Amount ask for Fe amount, then calculating formula is Fe 2O 3Amount * 55.85 * 2/159.7) NaOH neutralizes, and CH is arranged so 2=CHCOOH (molecular weight 72)+NaOH (molecular weight 40, Fe is about 7ppm) → CH 2=CHCOONa (molecular weight 94).In the Sodium Polyacrylate that is obtained, if neutralization ratio is the PAA (molecular weight 88.55) of 75 moles of %, then the Fe amount is the about 3ppm of 7ppm * 40/88.55=.The iron of this ormal weight promotes with the back water-absorbing resins when discarded to decompose, but excessive iron can cause using the time deterioration or use before painted, therefore not good enough.
The control of iron amount mainly is to supply the alkali (especially caustic soda) of neutralization to carry out through control.In addition, also can be to the trace iron in the raw material (acrylic acid, crosslinking agent, water etc.), and then resinous coat, glass coating, the stainless steel of various water-absorbing resins manufacturing installations such as polyplant and monomer pipe arrangement and pipe arrangement controlled, control the iron amount thus.In addition, the iron amount in the alkali, the iron amount in the water-absorbing resins can be carried out quantitatively through the ICP spectrophotometric spectra analytical method of putting down in writing among the JISK1200-6 for example.As the list of references of quantitative approach, can be with reference to No. the 2008/090961st, International Publication.
(b) grain shape
The grain shape of particulate water-absorbing agent of the present invention (water absorbing agent 1～water absorbing agent 3) is not limited to given shape, can enumerate: spherical, roughly spherical, (as crushed material) unsetting broken shape, bar-shaped, polyhedral, sausage-like (for example No. the 4973632nd, United States Patent (USP)), the particle (for example No. the 5744564th, United States Patent (USP)) of fold etc. arranged.They can be primary particle (single particle), also can be the granulation things, can also be these mixtures.In addition, particle can be the porous body that has foamed.As preferred particulates, can enumerate the primary particle or the granulation thing of unsetting broken shape.Through carrying out granulation, can reduce dust, and the surperficial ratio corresponding with particle diameter increased, and can improve absorption speed, therefore better with the mode of independent micro mist or with the mode that contains micro mist.
(c) granularity
With regard to water absorption character, water absorbing agent of the present invention (water absorbing agent 1～water absorbing agent 3) is a graininess, and preferably its weight average particle diameter (D50) is the scope of 200～600 μ m, the more preferably scope of 200～550 μ m, and then the scope of preferred 250～500 μ m.In addition, particle diameter is few more good more less than the particle of JIS standard screen 150 μ m, and its content is generally 0～5 weight %, preferred 0～3 weight %, especially preferred 0～1 weight %.And particle diameter is that the above particle of JIS standard screen 850 μ m is few more good more, and its content is generally 0～5 weight %, preferred 0～3 weight %, especially preferred 0～1 weight %.
The bulk specific gravity of water absorbing agent of the present invention No. the 6562879th, United States Patent (USP) (in regulation) is 0.30～0.90, and is preferred 0.50～0.80, more preferably 0.60～0.75.Granularity can be used above-mentioned pulverizing or classification to wait and control.
(d) other additives
And; In order to give various functions, can add water-insoluble inorganic or organic dust, deodorant, antiseptic, paper pulp and thermoplastic fibres etc. such as surfactant 0～3 weight %, preferred 0～1 weight %, oxidant, metallic soap to water absorbing agent of the present invention according to its objective function.In addition, as surfactant, the surfactant of record in No. the 2005/075070th, the preferred illustration International Publication.
(e) moisture content
The moisture content of particulate water-absorbing agent of the present invention (water absorbing agent 1～water absorbing agent 3) for example is 0.5～16% weight; Preferred 3～15 weight % (water absorbing agent 2 must have the moisture content of this scope); More preferably 4～14 weight %; And then preferred 5～13 weight %, especially preferred 6～12 weight %, and then preferred 7～11 weight %.As an example of moisture content adjustment method, for example can carry out dry and surface-crosslinked said regulation moisture content under, optionally also can further carry out the interpolation or the drying of water, control moisture content thus.Moisture content is that absorption speed (Vortex/FSR) can further improve when especially 3 weight % were above more than the 0.5 weight %, is difficult for causing the problem of foul smell and the decline of absorption speed, the decline of resistance to impact, the generation of dust etc.Moisture content is 15 weight % when following, can also suppress painted, and suppress the decline of particle adherence and water absorbent rate etc.If the moisture content of water absorbing agent is lower; Then absorption speed (Vortex/FSR) descends; And can the foul smell problem take place in the interpolation stage of inorganic reducing agent (if especially before surface-crosslinked step or this step), in addition, if moisture content is higher; Then there is to cause painted problem therefore preferred above-mentioned moisture content.
(f) do not have to add and depress water absorbent rate (CRC)
More than preferred 5 [g/g] of the CRC of the particulate water-absorbing agent among the present invention, more preferably more than 15 [g/g], and then more than preferred 25 [g/g].The higher limit of CRC is not special to be limited, but below preferred 70 [g/g], more preferably below 50 [g/g], and then below preferred 40 [g/g].If CRC is less than 5 [g/g], when so particulate water-absorbing agent being used as water-absorbing body, uptake is understood very few and is inappropriate in the hygienic materials such as being used in diaper.In addition, if CRC is greater than 70 [g/g], then adds sometimes and depress water absorbent rate (AAP) or permeability for liquids (SFC) descends, when being used as water-absorbing body such as paper nappy at particulate water-absorbing agent, water-absorbing body can't obtain the excellent liquid infiltration rate sometimes.Can use described internal crosslinking agent and surface crosslinking agent to wait and control CRC.
(g) add and depress water absorbent rate (AAP)
The AAP of the particulate water-absorbing agent among the present invention (under 2.0kPa, and then being under 4.83kPa) is more than 20 [g/g], more than preferred 22 [g/g], more preferably more than 23 [g/g], and then more than preferred 24 [g/g], most preferably more than 25 [g/g].The higher limit of AAP is not special to be limited, but below preferred 30 [g/g].If AAP is more than 20 [g/g], then when particulate water-absorbing agent is used for water-absorbing body, just contrary the oozing of liquid (common name Re-Wet) under the exerting pressure of the water-absorbing body that is obtained is still less.Can use described surface-crosslinked and granularity to wait and control AAP.
In addition, about the heavy burden condition of AAP, can come suitably to select 4.83kPa or 2.0kPa according to the type of desired particulate water-absorbing agent.As long as AAP shows above-mentioned number range, then arbitrary heavy burden condition all can, but preferably at 2.0kPa, and then under the heavy burden of 4.83kPa, satisfy said AAP.
(h) saline solution water conservancy diversion property (SFC)
The SFC of the particulate water-absorbing agent among the present invention preferred 30 [* 10 -7Cm 3Sg -1] more than, more preferably 50 [* 10 -7Cm 3Sg -1] more than, and then preferred 70 [* 10 -7Cm 3Sg -1] more than, especially preferred 80 [* 10 -7Cm 3Sg -1] more than.If SFC is 30 [* 10 -7Cm 3Sg -1] more than, then can further improve permeability for liquids, when particulate water-absorbing agent was used for water-absorbing body, the water-absorbing body that is obtained had more excellent liquid infiltration rate.The upper limit of SFC is not special specifies, but preferred 3000 [* 10 -7Cm 3Sg -1] below, more preferably 2000 [* 10 -7Cm 3Sg -1] below.If SFC is 3000 [* 10 -7Cm 3Sg -1] below, then when particulate water-absorbing agent is used for water-absorbing body, can control the fluid seepage of water-absorbing body.Can be through described surface-crosslinked, granularity control, or through CRC is controlled in the said scope, or, control SFC through multivalent metal salt shown in said " [7] multivalent metal salt and/or cation property copolymer " project and polyamine polymer etc.In addition, also saline solution water conservancy diversion property (SFC) is expressed as permeability for liquids or permeability for liquids (SFC) sometimes in this specification.
(i) absorption speed 1 (FSR)
About particulate water-absorbing agent of the present invention, more than preferred 0.1 [g/g/sec] of its FSR, more preferably more than 0.15 [g/g/sec], and then more than preferred 0.20 [g/g/sec], most preferably more than 0.25 [g/g/sec].The higher limit of FSR is not special specifies, but excessive high absorption speed (Vortex, FSR) can impair permeability for liquids (for example SFC), liquid diffusivity, therefore preferably below 5.0 [g/g/sec], is more preferably below 3.0 [g/g/sec].If FSR is more than 0.05 [g/g/sec], then for example when particulate water-absorbing agent is used for water-absorbing body, just can further suppress the situation that fluid seepage is not taken place by abundant absorption liquid.Can use described granularity, foaming polymerization to wait and control FSR.
(j) absorption speed 2 (Vortex)
About particulate water-absorbing agent of the present invention, its Vortex is preferred below 60 seconds, more preferably below 55 seconds, so that preferred below 50 seconds, most preferably below 40 seconds.The lower limit of Vortex is not special specifies, but preferred more than 10 seconds.If Vortex is below 60 seconds, then for example when particulate water-absorbing agent is used for water-absorbing body, can further suppress liquid is not produced fluid seepage by abundant absorption situation.Can use described granularity, foaming polymerization to wait and control Vortex.
(k) water soluble composition (Extr)
The water soluble composition of particulate water-absorbing agent of the present invention is necessary for below the 50 weight %, below the preferred 35 weight %, more preferably below the 25 weight %, and then below the preferred 15 weight %.If the water soluble composition is that then gel strength can further strengthen below the 35 weight %, permeability for liquids can be further excellent.In addition, when particulate water-absorbing agent was used for water-absorbing body, liquid is contrary under the exerting pressure of the water-absorbing body that is obtained oozed (common name Re-Wet) just still less.The water soluble composition can utilize described internal crosslinking agent to wait and control.
(1) remaining monomer
About particulate water-absorbing agent of the present invention, with regard to the viewpoint of security, remaining monomer is controlled in below the 500ppm, preferably is controlled at below the 400ppm, more preferably is controlled at below the 300ppm.Remaining monomer be except reducing through said polymerization or drying, can also reduce through the inorganic reducing agent that uses inorganic reducing agent, especially has an element sulphur.Water absorbing agent of the present invention so even if water absorbing agent is used in the paper nappy with high concentration mode (increase use amount), the remaining monomer of stripping is also less in the paper nappy, is good choosing because remaining monomer is few therefore.
(m) the initial stage tone (is claimed again: initial coloration)
Particulate water-absorbing agent of the present invention can preferably be used for hygienic materials such as paper nappy, preferably white powder.Utilize the beam splitting type colour difference meter that the particulate water-absorbing agent of just having made of the present invention is carried out the L value (Lightness) after upright (Hunter-Lab) color specification system in Hunter is measured, preferably show as 88 at least, and then show as more than 89, more preferably show as more than 90.In addition, the upper limit of L value is generally 100, if the L value during pulverulence is 88, then in goods such as hygienic material, can not produce the problem of tone.In addition, the b value of particulate water-absorbing agent of the present invention is 0～12, is preferably 0～10, and then is preferably 0～9; The a value is-3～3, is preferably-2～2, and then is preferably-1～1.
In addition, the initial stage tone is meant the tone after particulate water-absorbing agent is made, and is often referred to the tone of measuring before the shipment of workshop.In addition, if for example below 30 ℃, preserve under the environment of relative humidity 50%RH, then be from making back 1 year with interior measured value.
(n) through the time tone (claim again: through time painted)
Particulate water-absorbing agent of the present invention can preferably be used for hygienic materials such as paper nappy, even if preferred long term storage under higher levels of humidity or temperature conditions also can be kept obviously clean white states.Said long term storage state can promote test to check through the long term storage color stability.In this test; State the inspection condition of recording and narrating among the embodiment after comprising; After exposing 7 days under the environment of 70 ± 1 ℃ of temperature, relative humidity 65 ± 1%RH, utilize the beam splitting type colour difference meter to measure the L value (Lightness) of upright (Hunter-Lab) color specification system in Hunter of water absorbing agent particulate water-absorbing agent.After said long term storage color stability promotes test; The L value (Lightness) of utilizing the beam splitting type colour difference meter that particulate water-absorbing agent of the present invention is carried out upright (Hunter-Lab) color specification system mensuration in Hunter and getting preferably is at least more than 80; And then be preferably more than 81; And then be preferably more than 82, especially be preferably more than 83.In addition, the upper limit of L value is generally 100, if the long term storage color stability promotes that the L value after the test is more than 80, just even then quality has reached the level that under the condition of higher levels of humidity, temperature long term storage does not produce substantive issue yet.In addition, the b value is 0～15, is preferably 0～12, and then is preferably 0～10; The a value is-3～3, is preferably-2～2, and then is preferably-1～1.
[10] manufacturing approach of particulate water-absorbing agent
As an example of the manufacturing approach of particulate water-absorbing agent of the present invention, can implement through the method for record in said [1]～[8].
Particularly; This manufacturing approach is that polyacrylic acid (salt) is the manufacturing approach of particulate water-absorbing agent, and it may further comprise the steps: with the acrylic acid (salt) that contains 10～200ppm methoxybenzene phenols is the polymerization procedure of the monomer solution of principal component, drying steps, the surface-crosslinked step of aqueous gel shape cross-linked polymer that polymerization gets; It also comprises interpolation step, and the interpolation step of inorganic reducing agent of 0.001～0.5 weight % chelating agent; When converting with respect to acrylic acid, monomer contains the methoxybenzene phenols of 10～200ppm; And the project more than 1 in (a)～(c) below satisfying,
(a) also comprise the interpolation step of the inorganic microparticle of water-insoluble,
(b) behind drying steps, and in surface-crosslinked step, the moisture content of polymer is controlled at 3～15 weight %,
(c) after surface-crosslinked step, carry out the interpolation step of inorganic reducing agent.
According to said manufacturing approach, can obtain a kind of have excellent absorption properties and through the time the painted performance that prevents, more let the people surprised be foul smell is considerably less, and the excellent particulate water-absorbing agent that is suitable for being useful for absorber of urine patience.
In addition, in the manufacturing approach of particulate water-absorbing agent of the present invention, as preferably, the chelating agent of enumerating in said [1], [2] etc. is added to before the polymerization or the monomer solution in the polymerization process, prepare particulate water-absorbing agent thus.
In addition, in the manufacturing approach of particulate water-absorbing agent of the present invention,, the inorganic reducing agent of enumerating in said [1], [3] etc. is added to the aqueous gel shape cross-linked polymer before dry, prepare particulate water-absorbing agent thus as preferably.
In the manufacturing approach of particulate water-absorbing agent of the present invention,, also comprise the interpolation step of the alpha-hydroxy carboxylic acid compounds of enumerating in said [6] etc. (salt) as preferably.
In the manufacturing approach of particulate water-absorbing agent of the present invention, as preferably, also comprise the multivalent metal salt enumerated in said [7] etc. and/or the interpolation step of cation property copolymer.
In the manufacturing approach of particulate water-absorbing agent of the present invention, as preferably, also comprise the granulation step of explanation in said [8] etc.
And,, can implement through the method for record in said [1]～[8] as an example of the manufacturing approach of particulate water-absorbing agent of the present invention.Specific as follows.Polymerization procedure is: utilize 0.001～1 mole of % of radical polymerization initiator; In maximum temperature is below 130 ℃ and polymerization time is under 0.5 minute～3 hours the condition; Make and contain monomer solutions 90～100 moles of % of acrylic acid (salt), monomer concentration 30～55 weight % in the monomer, carry out aqueous solution polymerization or inverse suspension polymerization; Neutralization procedure is: utilizing Fe content is that the alkali of 0～10 (* 55.85 * 2/159.7) ppm neutralizes; Drying steps is: with 100～250 ℃ of baking temperatures, 10～120 minutes drying times, the moisture content of graininess aqueous gel is dried to below the 20 weight %; Surface-crosslinked step is: with respect to 100 weight portions of the absorbent resin powder behind the drying steps; Blending surface crosslinking agent 0.001～10 weight portion; And 70～300 ℃ of following heat treated 1 minute～2 hours, and with the methoxybenzene phenols content of the particulate water-absorbing agent that will obtain be controlled at 5～60ppm.The control of the methoxybenzene phenols content in the particulate water-absorbing agent that will obtain, can through above method or after state the carrying out of method.
Said methoxybenzene phenols in the manufacturing approach of particulate water-absorbing agent of the present invention; Can add in stage any time in the manufacturing step of particulate water-absorbing agent; Said methoxybenzene phenols preferably is contained in the said acrylic acid as the monomer principal component, preferably comes the content of said methoxybenzene phenols is suitably adjusted through the purifying acrylic acid step.
In the manufacturing approach of particulate water-absorbing agent of the present invention, the preferred acrylic acid that contains 10～200ppm methoxybenzene phenols that uses.
(10-1) acrylic acid
About the method for producing acrylic acid that uses among the present invention; As the known catalytic gas phase oxidation method that propylene and/or methacrylaldehyde arranged of industrial autofrettage, ethylene cyanohydrin method, high pressure Reppe process, improvement Reppe process, ketene process, acrylonitrile hydrolysis method etc., what wherein adopt at most is the vapour phase oxidation process of propylene and/or methacrylaldehyde.In the present invention, the preferred acrylic acid that uses through this vapour phase oxidation process obtained.
In the manufacturing approach of particulate water-absorbing agent of the present invention,, preferably use the monomer that contains 10～200ppm methoxybenzene phenols according to respect to acrylic acid scaled value.This monomer principal component can be acrylic acid, also can be acrylic acid and acrylates.As said methoxybenzene phenols, particularly, but illustration o-methoxyphenol, meta-methoxy phenol, p methoxy phenol, or further have substituent methoxybenzene phenols such as 1 or 2 above methyl, the tert-butyl group, hydroxyl on these phenol.Especially preferably use p methoxy phenol among the present invention.
About the content of methoxybenzene phenols, according to respect to acrylic acid scaled value, preferably 10～120ppm is more preferably 10～90ppm, and then preferred 20～90ppm.If the content of p methoxy phenol is below the 200ppm, painted (jaundice/xanthochromia) of the water-absorbing resins that then can suppress to be obtained.In addition; If the content of p methoxy phenol is less than 10ppm, that is, if removed p methoxy phenol as polymerization inhibitor through purifying such as distillations; The danger that polymerization takes place before intention beginning polymerization is then arranged; And as above-mentioned, be that the weatherability of water-absorbing resins or the water absorbing agent of main material also can variation with acrylic acid (salt), so not good enough.
In addition; Because the molecular weight of the acrylates after optionally neutralizing (for example can increase; Molecular weight with sodium salt among 75 moles of % is 88.5), and also can optionally add the composition of enumerating in said [2]～[7], therefore; When being benchmark, the content of methoxybenzene phenols can reduce on relativity ground the amount of the methoxybenzene phenols during polymerization with acrylic acid (molecular weight 72).In addition, the consumption during in view of polymerization, among the present invention, with respect to the content 10～200ppm of the methoxybenzene phenols in the acrylates before the polymerization, the methoxybenzene phenols in the polyacrylate of acquisition is 5～60ppm.
Preferred experience following steps in the manufacturing approach of particulate water-absorbing agent of the present invention: make the acrylic acid monomer solution that contains 10～200ppm methoxybenzene phenols (especially p methoxy phenol), carry out polymerization.And; Through experiencing this polymerization procedure (concentration, initator, temperature) and drying steps (temperature, time, solid constituent, air quantity etc.); Can consume the metoxyphenol of ormal weight; Therefore the particulate water-absorbing agent that is obtained can contain the metoxyphenol (especially p methoxy phenol) of 5～60ppm, especially can contain metoxyphenol (especially p methoxy phenol) equably in polymer inside according to said scope.
Promptly; Manufacturing approach of the present invention can be following manufacturing approach: through using methoxybenzene phenols content is the monomer of 10～200ppm; And, make the methoxybenzene phenols of the water-absorbing resins that is obtained become 5～60ppm through said radical polymerization step and drying steps.
In addition, it is an above-mentioned example that the control method of the metoxyphenol in the water-absorbing resins is not limited to, but as the method below the additive method illustration, also can and use those methods.
Manufacturing approach 2: make the water-absorbing resins polymerization not existing methoxybenzene phenols or methoxybenzene phenols to be lower than under the situation of 10ppm, afterwards and then after drying, add the methoxybenzene phenols of ormal weight.
Manufacturing approach 3: after making the excessive monomer polymerization that contains the methoxybenzene phenols become water-absorbing resins, before dry, remove the methoxybenzene phenols of ormal weight through cleaning.In addition, can make water or alcohol-water mixture during cleaning.
In addition,, in manufacturing step, can use the polymerization inhibitor beyond the p methoxy phenol, also can and use this polymerization inhibitor and p methoxy phenol for the monomer that uses among the present invention.
Polymerization inhibitor as beyond the p methoxy phenol more for example has coffee thiazine, hydroquinones, mantoquita, manganese acetate, methylene blue etc.But these polymerization inhibitors are different with metoxyphenol, can hinder polymerization, so are few more good more on final.If with p methoxy phenol and usefulness, the preferred 0.01～10ppm of its concentration in monomer then.
In addition; Under the prerequisite that solves problem of the present invention (preventing painted), the amount of moisture in the acrylic acid is few more good more, is generally below the 1000ppm; Below the preferred 750ppm; And then below the preferred 500ppm, more preferably below the 300ppm, below the preferred especially in regular turn 200ppm, below the 100ppm, below the 80ppm, below the 50ppm.Though moisture is few more good more, because the dehydration cost, with about 1ppm and then be good about 5ppm.In order to obtain this low-moisture acrylic acid, can distill repeatedly or partial crystallization purifying acrylic acid is adjusted to till the moisture of ormal weight, or acrylic acid is contacted with inorganic or organic dehydrating agent, thereby makes moisture become ormal weight.If the amount of moisture in the monomer surpasses 1000ppm, the tendency that worsens takes place in painted (especially through time painted) of the water-absorbing resins that then obtains to some extent.
The principal component of monomer is acrylic acid and/or acrylates, but these acrylic acid are different with acrylates molecular weight each other.Consider the difference of this molecular weight, defined " with respect to acrylic acid scaled value " in the present invention.Be meant with respect to acrylic acid scaled value: when acrylates such as all is converted at the unneutralized acrylic acid of mole, the weight of said micro constitutent is with respect to containing of acrylic acid weight proportional (weight ratio).Promptly; For example for the PAA (molecular weight 94) after the neutralization; Earlier it is converted into the weight of acrylic acid (molecular weight 72),, comes the containing of said micro constitutent such as regulation p methoxy phenol proportional (weight ratio) etc. then according to the convert weight of back (being converted into 72) of acrylic acid with 94.In the particulate water-absorbing agent after polymerization; If polymer is the acrylates that part neutralizes or neutralizes fully; Then be earlier will the part neutralization or the polyacrylate of neutralization fully all be converted into and wait the unneutralized polyacrylic acid of mole, then in calculating with respect to acrylic acid scaled value.The neutralization of said part be meant neutralization ratio surpass 0 mole of %, less than 100 moles of %.Said neutralization fully is meant that neutralization ratio is 100 moles of %.Said not neutralization is meant that neutralization ratio is 0 mole of %.
In addition, quantitatively can the utilize liquid chromatography or the gas chromatography of said composition carry out.
(10-2) nertralizer
In addition, about among the present invention in order in nertralizers (alkali) such as the caustic soda of monomer or polymer or sodium carbonate, iron content wherein is few more good more.Usually, this iron content is (as Fe 2O 3Scaled value) is the scope of 0～10.0ppm with respect to the alkali solid constituent, is preferably 0.2～5.0ppm, the scope of 0.5～5.0ppm more preferably.If the content of iron is less than 0.01ppm, the danger that polymerization takes place before polymerization initiator adds is then not only arranged, added the possibility that the initator polymerization also postpones on the contrary even if also exist.As described iron, can be the Fe ion, but with regard to the effect aspect, the iron of preferred 3 valencys, especially preferred Fe 2O 3In addition, in said scope, molecular weight ratio (55.85 * 2/159.7 (Fe of equal available iron and iron oxide 2O 3In Fe)) calculate Fe amount.
Among the present invention, regardless of the kind of balance anion, the absolute magnitude of Fe is all very important.At this, Fe 2O 3Conversion is meant: regardless of balance anion (the for example oxide of Fe (II) or Fe (III), sulfate, hydrochloride, hydroxide etc.), all being regarded as is the oxide Fe of Fe (III) 2O 3In Fe amount.According to Fe (molecular weight 55.85) and Fe 2O 3Molecular weight (159.7), the good Fe of the choosing amount (Fe conversion) in the alkali of the present invention is 0～7.0ppm.
If the content of iron is less than 0.01ppm, the danger that polymerization takes place before polymerization initiator adds is then not only arranged, added the possibility that the initator polymerization also postpones on the contrary even if also exist.As the iron that uses among the present invention, can be the Fe ion, but with regard to the effect aspect, preferred 3 valency iron, especially preferred Fe 2O 3Perhaps iron hydroxide.
This promptly, among the present invention, preferably using Fe content (Fe conversion) is that the alkali (especially being controlled to the NaOH or the sodium carbonate of this Fe content) of 0～7.0ppm is implemented neutralization procedure, and then the scope of preferred said Fe content.
(10-3) adding method of inorganic reducing agent
Adding method about the inorganic reducing agent in the manufacturing approach of particulate water-absorbing agent of the present invention; Can wherein add in more than one the step at these of said (1-6) polymerization procedure, (1-7) gel grain refined step, (1-8) drying steps, (1-9) pulverising step/classification step, (1-10) surface-crosslinked step, (1-11) other steps; Not special the qualification; But preferably inorganic reducing agent being processed Powdered, solution, emulsion or suspension adds; Preferably process solution and add, more preferably process the aqueous solution and add.
If the inorganic reducing agent in the manufacturing approach of particulate water-absorbing agent of the present invention adds with Powdered, preferred 0.001～850 μ m of the average grain diameter of its powder particle then, more preferably 0.01～600 μ m, and then preferred 0.05～300 μ m.About average grain diameter, can utilize laser to measure volume average particle size.As an example of laser, disclose in No. 2004/0110006 on the books at U.S. Patent application.
If the inorganic reducing agent in the manufacturing approach of particulate water-absorbing agent of the present invention adds with the solution mode, the solvent that then uses this moment is not special to be limited, and for example can preferably use: water; Alcohols such as ethanol, methyl alcohol, propane diols, glycerine; Polyethylene glycol etc.Wherein, preferably make the mixed solution of water or water and alcohols, most preferably process the aqueous solution and add.In addition, the concentration of the inorganic reducing agent in this solution can suitably determine, can be dispersion liquid or the supersaturated solution that surpasses saturated concentration, but states the solution of concentration range after preferred, states the aqueous solution of concentration range after especially preferred.Upper limit of concentration is a saturated concentration.
In addition, if said inorganic reducing agent mixes with form of suspension, the decentralized medium that then uses this moment is not special to be limited, and for example can preferably use: water; Alcohols such as ethanol, methyl alcohol, propane diols, glycerine; Polyethylene glycol etc.In addition, the concentration of the said inorganic reducing agent in this dispersion liquid is 1～100 weight % preferably, preferred especially 10～100 weight %.In addition, can further add water-soluble polymer, surfactant etc. and be used as dispersant.
And said inorganic reducing agent is except processing solution or the suspension, can also for example forming emulsion in the water with emulsifying agent, and then mix with water-absorbing resins.Decentralized medium in this scheme is not special to be limited, and for example can make water etc. aptly.
In addition, emulsifying agent is not special to be limited, and uses nonionic surfactant, cationic surfactant etc. to get final product.In addition, the concentration of the said inorganic reducing agent in this emulsion is 1～90 weight % preferably, is more preferably 10～90 weight %.
And, in the manufacturing approach of particulate water-absorbing agent of the present invention, and then preferably said inorganic reducing agent is processed the aqueous solution and adds.In addition, the concentration of the inorganic reducing agent in this aqueous solution is 0.01～90 weight % preferably, is more preferably 0.5～60 weight %, and then 1～90 weight % preferably, and especially preferably 10～60 weight % most preferably are 10～90 weight %.In addition, also can process the upper limit and drop on dispersion liquid or supersaturated solution in the said scope, be limited to saturated concentration on it.
In the manufacturing approach of particulate water-absorbing agent of the present invention; Inorganic reducing agent can add to the crosslinked body of aqueous gel shape in the monomer solution before the polymerization, the polymerization or after the polymerization, also can be before surface-crosslinked step, add these any periods after the surface-crosslinked step.More preferably add to give in the polymerization process, the aqueous gel shape cross-linked polymer after the polymerization (that is, the aqueous gel shape cross-linked polymer before dry), perhaps after surface-crosslinked step, add.
If add inorganic reducing agent in the aqueous gel shape cross-linked polymer after polymerization; Add inorganic reducing agent in the grain refined step of then preferred aqueous gel shape cross-linked polymer after polymerization, perhaps to through grain refined polymerization after aqueous gel shape cross-linked polymer add and mix inorganic reducing agent.If when surface-crosslinked, added inorganic reducing agent; Or as patent documentation 15, before surface-crosslinked, added inorganic reducing agent; If then like this moisture content is controlled at 3～15 weight % unlike the present invention, so not only particulate water-absorbing agent can take place paintedly, and foul smell can strengthen.
In addition,, then carry out not special qualification the in period of said interpolation step if after surface-crosslinked step, can be before the interpolation of said multivalent metal salt and/or cation property copolymer, add in, interpolation on the wherein random time point after adding.And, also can be before the interpolation of said alpha-hydroxy carboxylic acid compounds compound, add in, interpolation on the wherein random time point after adding.
Inorganic reducing agent in the manufacturing approach of particulate water-absorbing agent of the present invention preferably adds the back at it and mixes with said polyacrylic acid (salt) water-absorbent resin, or when adding, mixes with said polyacrylic acid (salt) water-absorbent resin.The concrete mixed method of adding or mixing is not special to be limited, and can use known crushing device, reducing mechanism or agitating device to mix.
As this crushing device, reducing mechanism, but illustration kneader and screw type extruder with any shape loose structure (are claimed again: meat grinder).In addition, many should can be used in crushing devices series connection, also can with and with these different devices such as kneader and meat grinders.The screw type extruder can use 1, also can use more than 2.As the agitating device among the present invention, for example can use aptly: cylinder type mixer, screw type mixer, screw type extruder, continous way mixer, conical type mixer, V-Mixer, double-arm kneader, flow-type mixer, airflow mixer, rotational circle dish-type mixer, rolling wheel formula mixer, roller mixer, Luo Dige mixer, dasher, ribbon blender, rotary agitator, pot type rotating cylinder, piston type mixer, mortar mixing machine etc.In addition, said agitating device can possess heater, with to containing polyacrylic acid (salt) water-absorbent resin after surface-crosslinked, said inorganic reducing agent, and optionally and the mixture of said other additives that add heats.Also can possess the cooling device that said mixture that heater is heated cools off.The mixing time of said agitating device is not special to be limited, preferred below 60 minutes, more preferably below 30 minutes.
(10-4) adding method of chelating agent
Said chelating agent in the manufacturing approach of particulate water-absorbing agent of the present invention is not only can said (1-6) polymerization procedure～(1-10) surface-crosslinked step and (1-11) any time in other steps go up and add, also can be to add on any time in the particulate water-absorbing agent manufacturing step.But preferably in said (1-6) polymerization procedure, the monomer solution before polymerization or in the polymerization process adds chelating agent.If before polymerization or the monomer solution in the polymerization process add chelating agent, chelating agent is included in the particulate water-absorbing agent equably, therefore from effectively prevent through the time painted viewpoint, this scheme is especially preferred.
If the monomer solution in said (1-6) polymerization procedure before polymerization adds chelating agent, then preferably with monomer pipeline that the polymerisation machine links to each other in mix chelating agent, or in the reaction machine, mix the stirring chelating agent.In addition, if in polymerization process, add chelating agent, then preferably after polymerisation and before polymerisation arrives peak temperature, add chelating agent; Perhaps, after polymerisation and before the polymerisation machine is discharged polymer, add chelating agent.Through when the polymerization or polymerization process in monomer solution add chelating agent, chelating agent is added in the particulate water-absorbing agent of the present invention equably, can further bring into play effect of the present invention thus, thereby be the good scheme of selecting.
(10-5) adding method of the inorganic microparticle of water-insoluble
In the manufacturing approach of particulate water-absorbing agent of the present invention; The inorganic microparticle of said water-insoluble is not only can be in the surface-crosslinked step of said (1-6) polymerization procedure～(1-10) and (1-11) any time in other steps goes up and adds; Also can be to add on any time in the particulate water-absorbing agent manufacturing step, but preferably after (1-10) surface-crosslinked step, add.That is, preferably the inorganic microparticle of water-insoluble and said surface crosslinking agent are added simultaneously and make water-absorbing resins surface-crosslinked; Or, utilize said surface crosslinking agent make water-absorbing resins surface-crosslinked after, add the inorganic microparticle of water-insoluble again.Especially, carry out surface treatment, can reach required water absorption character, especially can realize higher liquid Penetration Signature through in the water-absorbing resins of having implemented with surface crosslinking agent after surface-crosslinked, adding the inorganic microparticle of water-insoluble.In addition, the inorganic microparticle of water-insoluble preferably adds with said alpha-hydroxy carboxylic acid compounds compound simultaneously, or is made in advance to add with the mixture of alpha-hydroxy carboxylic acid compounds compound.
(10-6) adding method of alpha-hydroxy carboxylic acid compounds compound
In the manufacturing approach of particulate water-absorbing agent of the present invention; Said alpha-hydroxy carboxylic acid compounds compound is not only can be in the surface-crosslinked step of (1-6) polymerization procedure～(1-10) and (1-11) any time in other steps goes up and adds; Also can be to add on any time in the particulate water-absorbing agent manufacturing step; But consider through the time colour stable effect; The alpha-hydroxy carboxylic acid compounds compound can be included in the polymerizable monomer in advance, preferably adds the alpha-hydroxy carboxylic acid compounds compound in the late stage step after said polymerisation finishes.About the method for adding in the back segment step after polymerisation finishes, preferably: add in the aqueous gel shaped polymer after polymerization in the method, the dry thing behind drying steps of alpha-hydroxy carboxylic acid compounds compound and add the method for alpha-hydroxy carboxylic acid compounds compound, in surface-crosslinked treatment step or adding the method for alpha-hydroxy carboxylic acid compounds compound thereafter.
In the manufacturing approach of particulate water-absorbing agent of the present invention; The adding method of alpha-hydroxy carboxylic acid compounds compound is not special to be limited; Add but preferably process Powdered, solution, emulsion or suspension, more preferably process solution and add, and then preferably process the aqueous solution and add.And then the alpha-hydroxy carboxylic acid compounds compound also can add with said chelating agent, multivalent metal salt and/or cation property copolymer, the inorganic microparticle of water-insoluble simultaneously, or also can process the mixture that mixes with these compositions in advance and add.
(10-7) adding method of multivalent metal salt and/or cation property copolymer
In the manufacturing approach of particulate water-absorbing agent of the present invention; Said multivalent metal salt and/or cation property copolymer are not only can be in the surface-crosslinked step of said (1-6) polymerization procedure～(1-10) and (1-11) any time in other steps goes up and adds; Also can be to add on any time in the particulate water-absorbing agent manufacturing step, but preferably when surface treatment, add.
That is, institute's preferable methods has: in said (1-10) surface-crosslinked step, multivalent metal salt and/or cation property copolymer and said surface crosslinking agent are added simultaneously, make water-absorbing resins surface-crosslinked thus; Or, make with said surface crosslinking agent water-absorbing resins surface-crosslinked after, add multivalent metal salt and/or cation property copolymer as the 2nd surface-crosslinked step.Multivalent metal salt and/or cation property copolymer be as (the 1st or the 2nd) surface crosslinking agent, and react with the functional group of polyacrylic acid water-absorbent resin, and ionic bonding especially takes place, and therefore can further improve the physical property of the water absorbing agent that is obtained.Especially; Through in the water-absorbing resins of having implemented with surface crosslinking agent after surface-crosslinked, adding multivalent metal salt and/or cation property copolymer carries out surface treatment; Can reach required water absorption character, especially can realize higher liquid Penetration Signature (SFC).In addition, multivalent metal salt and/or cation property copolymer preferably add with said alpha-hydroxy carboxylic acid compounds compound simultaneously, or the mixture of processing in advance with the alpha-hydroxy carboxylic acid compounds compound adds.In the prior art, it is painted that the use of multivalent metal salt and/or cation property copolymer causes that sometimes water-absorbing resins takes place, but no problem among the present invention, can utilize multivalent metal salt and/or cation property copolymer to improve physical property.
(10-8) drying after the interpolation
In addition, can after the interpolation step of said (10-3)～(10-7), carry out drying to obtaining mixture.At this, preferably use the time more than 50% of drying steps time, be good through whole drying steps in fact, and preferably carrying out drying in less than 100 ℃ temperature range more than 40 ℃.Therefore through in this temperature range, carrying out drying, water absorbing agent can not be heated and damage, and can not cause harmful effect to the physical property of the water absorbing agent that obtained.
In addition, baking temperature stipulates with heat medium temperature, but if what adopt is the microwave that can't stipulate with heat medium temperature etc., then stipulates with material temperature.As drying means,, can use heated-air drying, calm drying, drying under reduced pressure, infrared drying, microwave drying etc. aptly as long as baking temperature in said scope, does not then limit especially.More preferably 40 ℃～100 ℃ of the scopes of baking temperature, and then preferred 50 ℃～90 ℃ temperature range.In addition, drying can be carried out under fixing temperature, and variations in temperature is carried out, preferably all drying steps in fact all with said temperature range do dry reach to after the moisture content stated.
The kind that depends on surface area, moisture content and the drying machine of water absorbing agent drying time.Can suitably select drying time, so that moisture content becomes desired value.Be generally 10～120 minutes drying time, more preferably 20～90 minutes, and then preferred 30～60 minutes.Drying time is during less than 10 minutes, then dry sometimes insufficient, operability is insufficient.In addition; Be more than 120 minutes the time drying time, then can cause damage to water absorbing agent because of over-drying, and the result produces foul smell (supposition is the plyability foul smell of inorganic reducing agent and water-absorbing resins); Or cause that water soluble becomes component to rise, and can not get the raising effect of various physical propertys sometimes.Can be adjusted into below the 5 weight % through the moisture content of this drying steps particulate water-absorbing agent of the present invention.
Preferred 3～15 weight % of dried moisture content, more preferably 4～14 weight %, and then preferred 5～13 weight %, especially preferred 6～12 weight %, and then preferred 7～11 weight %.As an example of the method for adjustment of moisture content, can the aforesaid method of illustration.
Having disclosed a kind of water-absorbing resins, oxygen-containing reducing inorganic salts, amino carboxylic acid of containing in the said patent documentation 17 (No. 1645596 specification of European patent) is the water absorbency resin composition with coloring resistance property that metal-chelator and organic oxidation-resistant agent become; But disclose to use the p methoxy phenol and the water-insoluble microparticle of specified quantitative, also do not put down in writing the importance of moisture content of the water absorbency resin composition of gained.Among the embodiment of patent documentation 17; Use the water-absorbing resins 214.4g that obtains as monomer with the 80 weight % acrylic acid (92g+119.1g) and the 30 weight %NaOH aqueous solution (102.2g+132.2g) etc. that makes in the example; Do not having under the situation of solvent; With oxygen-containing reducing inorganic salts, amino carboxylic acid among the embodiment 1-7 is that metal-chelator and organic oxidation-resistant agent mix, and obtains water absorbency resin composition thus.Therefore, in patent documentation 17, moisture content is 17 weight % in the water-absorbing resins of calculating according to the raw material (g) and the output (212.2g) of water-absorbing resins.Therefore, patent documentation 17 do not disclose the present invention 3～15 weight % of good choosing, and then the moisture content of 4～14 weight %, 5～13 weight %, 6～12 weight %, 7～11 weight %.In addition, though disclosed organic oxidation-resistant agent (paragraph [0019] [0020] [embodiment 6]) such as (butyl etc.) alkyl hydroxy methyl phenyl ethers anisole in the patent documentation 17, do not disclose the p methoxy phenol of trace.
[11] water-absorbing body
Water-absorbing body of the present invention comprises particulate water-absorbing agent of the present invention.Be suitable for as the for example water-absorbing body of hygienic material absorbed layer through particulate water-absorbing agent of the present invention and the material that is fit to being made up, can processing.Below water-absorbing body of the present invention is described.Water absorbing agent of the present invention is a white, and permeability for liquids, add depress water absorbent rate, absorption speed is higher, therefore remaining monomer is also less, can preferably be used for water-absorbing body, the especially diaper of high concentration.
In the present invention, water-absorbing body is meant the composition that can be used for hygienic material of absorbing blood, body fluid, urine etc., is the composition after being shaped that comprises particulate water-absorbing agent and other materials.At this,, for example can enumerate paper nappy, sanitary napkin, incontinence protection, medical protection pad etc. as said hygienic material.As other materials that are used for water-absorbing body, can enumerate cellulose fibre.
As the concrete example of said cellulose fibre, but illustration for example: from wood pulp fibers such as the mechanical pulp of timber, chemical pulp, semichemical wood pulp, dissolving pulps; Man-made cellulose fibers such as artificial silk (rayon), acetate fiber etc.Preferred cellulose fibre is the wood pulp fiber.In addition, these cellulose fibres also can contain synthetic fibers such as some nylon, polyester.
With particulate water-absorbing agent of the present invention during as water-absorbing body a part of, the content of contained said particulate water-absorbing agent is preferably more than the 20 weight % in the water-absorbing body, more preferably more than the 30 weight %, and then the above scope of preferred 50 weight %.If the weight of contained particulate water-absorbing agent of the present invention then has the worry that can't obtain sufficient assimilation effect less than 20 weight % in the water-absorbing body.
When using particulate water-absorbing agent of the present invention and cellulose fibre to make water-absorbing body; For example can suitably select for use following being used for to obtain the known method of water-absorbing body:, optionally to wait the clamping particulate water-absorbing agent with these paper, mat comprising the said water absorbing agents of distribution such as the paper of cellulose fibre, mat; With cellulose fibre and water absorbing agent fusion etc. equably.As preferred method, for example have in the method for particulate water-absorbing agent and cellulose fibre dry type having been carried out mix back and then compression.Through this method, can show the inhibition particulate water-absorbing agent and come off from cellulose fibre.Compression is preferably carried out under heating, and its temperature range for example is 50～200 ℃.
Particulate water-absorbing agent of the present invention is when being used for water-absorbing body, and various physical propertys are all excellent, so it is fast to obtain liquid-absorbent, and the very excellent water-absorbing body that the liquid remaining quantity on water-absorbing body top layer is few.
Because particulate water-absorbing agent of the present invention has the excellent water-absorbing characteristic, so can be as the water-absorbing water-retaining agent of various uses.Particularly, for example can be used for absorbing articles such as paper nappy, sanitary napkin, incontinence protection, medical protection pad and use water-absorbing water-retaining agent; Agriculture and gardens such as fountain moss substitute, the agent of soil modification and improvement, water-loss reducer, the lasting agent of pesticide effectiveness are used water-loss reducer; Interior dress wall material is with water-loss reducers for building such as anti-caking distillate medicinal water, cement additires; The dehydrating agent of controlled release agent, cold-retaining agent, warm subsides, mud coagulating agent, Shelflife-improving agent for food, ion-exchange column material, greasy filth or oil, drier, humidity adjustment material etc.Wherein, water absorbing agent of the present invention especially suitable use absorption at these excrement, urine or blood such as paper nappy, sanitary napkins with hygienic material in.
If water-absorbing body of the present invention is used for hygienic materials such as paper nappy, sanitary napkin, incontinence protection, medical protection pad, the then preferred goods that include following (a)～(c) that adopt: (a) with the health of wearer in abutting connection with the permeability for liquids top laminate of configuration, (b) away from the health of wearer and the clothing of wearer in abutting connection with the liquid impermeability base lamina of configuration, reach the water-absorbing body that (c) is configured between top laminate and the base lamina.Water-absorbing body can be for more than two-layer, also can use with pulp layer etc.
Above-mentioned particulate water-absorbing agent of the present invention also can be changed to following saying.
(1) a kind of with the particulate water-absorbing agent of polyacrylic acid (salt) water-absorbent resin as principal component, it is characterized in that: the methoxybenzene phenols, chelating agent and the inorganic reducing agent that contain 5～60ppm.
(2) a kind of with the particulate water-absorbing agent of polyacrylic acid (salt) water-absorbent resin as principal component, it is characterized in that: contain the inorganic microparticle of chelating agent, inorganic reducing agent and water-insoluble.
(3) a kind of with the particulate water-absorbing agent of polyacrylic acid (salt) water-absorbent resin as principal component; It is being principal component through surface-crosslinked polyacrylic acid (salt) water-absorbent resin; It is characterized in that: contain inorganic reducing agent and chelating agent, p methoxy phenol, and moisture content is 3～15 weight %.
In addition, likewise, the manufacturing approach of particulate water-absorbing agent of the present invention can be changed to following saying.
(1) a kind of manufacturing approach of particulate water-absorbing agent; It may further comprise the steps: with the acrylic acid (salt) that contains 10～200ppm methoxybenzene phenols is the interpolation step of the drying steps of the polymerization procedure of the monomer solution of principal component, aqueous gel shape cross-linked polymer that polymerization gets, surface-crosslinked step, chelating agent, and this manufacturing approach is characterised in that:
After surface-crosslinked step, carry out the interpolation step of inorganic reducing agent.
(2) a kind of manufacturing approach of particulate water-absorbing agent, it may further comprise the steps: with acrylic acid (salt) is the polymerization procedure of the monomer solution of principal component, the drying steps of aqueous gel shape cross-linked polymer that polymerization gets, and this manufacturing approach is characterised in that:
The interpolation step that comprises interpolation step, inorganic reducing agent and the inorganic microparticle of water-insoluble of surface-crosslinked step, chelating agent.
(3) a kind of with the manufacturing approach of polyacrylic acid (salt) water-absorbent resin as the particulate water-absorbing agent of principal component; It may further comprise the steps: with the acrylic acid (salt) that contains 10～200ppm methoxybenzene phenols is the interpolation step of drying steps, surface-crosslinked step, inorganic reducing agent and the chelating agent of the polymerization procedure of the monomer solution of principal component, aqueous gel shape cross-linked polymer that polymerization gets, and this manufacturing approach is characterised in that:
Moisture content with polymer in drying steps and surface-crosslinked step is controlled at 3～15 weight %.
The present invention is not limited to each above-mentioned example, can in the scope shown in the claim, carry out various changes, the technical scheme that discloses separately in the different embodiments of appropriate combination and the embodiment that obtains is also included within the technical scope of the present invention.
(the suitable subordinate concept of said particulate water-absorbing agent)
(manufacturing approach 1 of particulate water-absorbing agent)
The manufacturing approach 1 of the subordinate concept of particulate water-absorbing agent manufacturing approach of the present invention must satisfy said important document (c); This manufacturing approach 1 is the manufacturing approach of the particulate water-absorbing agent that comprises the steps: with the acrylic acid (salt) that contains 10～200ppm methoxybenzene phenols is the interpolation step of the drying steps of the polymerization procedure of the monomer solution of principal component, aqueous gel shape cross-linked polymer that polymerization gets, surface-crosslinked step, 0.001～0.5 weight % chelating agent, and this manufacturing approach 1 is characterised in that: the interpolation step of after surface-crosslinked step, carrying out inorganic reducing agent.The concrete example of this manufacturing approach 1 is among the embodiment 1-1～1-16 and table 1～5 that states after being shown in.
(manufacturing approach 2 of particulate water-absorbing agent)
The manufacturing approach 2 of the subordinate concept of particulate water-absorbing agent manufacturing approach of the present invention must satisfy said important document (b); This manufacturing approach 2 is manufacturing approaches of the particulate water-absorbing agent that comprises the steps: with acrylic acid (salt) is the polymerization procedure of the monomer solution of principal component, drying steps, the surface-crosslinked step of aqueous gel shape cross-linked polymer that polymerization gets, and this manufacturing approach 2 is characterised in that: also comprise the interpolation step of 0.001～0.5 weight % chelating agent and the interpolation step of inorganic reducing agent; When converting with respect to acrylic acid, monomer contains the methoxybenzene phenols of 10～200ppm, also comprises the interpolation step of the inorganic microparticle of important document (a) water-insoluble.The concrete example of this manufacturing approach 2 is among the embodiment 2-1～2-14 and table 6～7 that states after being shown in.
(manufacturing approach 3 of particulate water-absorbing agent)
The manufacturing approach 3 of the subordinate concept of particulate water-absorbing agent manufacturing approach of the present invention must satisfy said important document (c); This manufacturing approach 3 is manufacturing approaches of the particulate water-absorbing agent that comprises the steps: with acrylic acid (salt) is the polymerization procedure of the monomer solution of principal component, drying steps, the surface-crosslinked step of aqueous gel shape cross-linked polymer that polymerization gets, and this manufacturing approach 3 is characterised in that: also comprise the interpolation step of 0.001～0.5 weight % chelating agent and the interpolation step of inorganic reducing agent; When converting with respect to acrylic acid, monomer contains the methoxybenzene phenols of 10～200ppm; Behind the drying steps and/or in surface-crosslinked step, the moisture content of polymer is controlled at 3～15 weight %; And then preferably the aqueous gel shape cross-linked polymer before dry adds said inorganic reducing agent.The concrete example of this manufacturing approach 3 is among the embodiment 3-1～3-13 and table 8～9 that states after being shown in.
[embodiment]
Below, the present invention will be described according to embodiment, but the present invention does not receive embodiment to limit, explain.In addition, the various physical propertys of putting down in writing among claim scope of the present invention or the embodiment are to try to achieve according to following determination method.In addition, following determination method is recorded and narrated to particulate water-absorbing agent, but for water-absorbing resins, also particulate water-absorbing agent is called water-absorbing resins and measures.In addition, the electric equipment that uses among the embodiment uses under the condition of 200V or 100V and 60Hz.In addition, short of special appointment, then particulate water-absorbing agent uses under 25 ℃ ± 2 ℃, the condition of relative humidity 50%RH.Illustrative reagent or utensil can suit to utilize suitable article to replace among following determination method or the embodiment.
In addition, particulate water-absorbing agent of the present invention must contain inorganic reducing agent, and hereinafter, the water-absorbing resins before surface-crosslinked and interpolation inorganic reducing agent is sometimes referred to as particulate water-absorbing agent presoma (reference: embodiment 1-1～1-8, comparative example 1-3,1-4 etc.).
[evaluation method of physical property]
[CRC]
Particulate water-absorbing agent 0.2g is added into the fabric sack of nonwoven equably, and (also sealing in 60 * 60mm) impregnated in the 0.9 weight % sodium-chloride water solution that is adjusted into 25 ± 3 ℃ thereafter and (claims again: normal saline solution) among the 500g.After 60 minutes, mention sack, use centrifugal separator to dewater 3 minutes with 250G, measure the weight W 1 [g] of sack thereafter.Do not add particulate water-absorbing agent and carry out identical operations, and try to achieve the weight W 2 [g] of this moment.Calculate CRC (nothing add depress water absorbent rate) according to following formula.
[formula 1]
CRC[g/g]＝(W1-W2)/0.2-1
[water soluble composition]
In the plastic containers with cover of capacity 250ml, add sodium-chloride water solution 184.3g and the particulate water-absorbing agent 1.00g of 0.90 weight %, stirred 16 hours, and the water soluble composition in the extraction particulate water-absorbing agent.Use 1 filter paper (Japan ADVANTEC limited company, the name of an article: JIS P 3801, No.2, thickness 0.26mm, keep particle diameter 5 μ m) to filter this extract, and with the 50.0g of the filtrating that obtained as measuring solution.
Then, carry out titration with the NaOH aqueous solution of 0.1N and become 10, carry out titration with the HCl aqueous solution of 0.1N thereafter and become 2.7 until the pH value until the pH value.Try to achieve the titer ([NaOH] ml, [HCl] ml) of this moment.In addition, only the sodium-chloride water solution 184.3g to 0.90 weight % carries out identical titration operation, and tries to achieve blank titration amount ([bNaOH] ml, [bHCl] ml).
Under the situation that is particulate water-absorbing agent of the present invention, based on the mean molecule quantity of monomer whose and the titer that is obtained by said operation, the water soluble composition in the particulate water-absorbing agent can be calculated according to following formula 2.In addition, under the mean molecule quantity condition of unknown of monomer, use the neutralization ratio of utilizing titration to try to achieve can calculate the mean molecule quantity of monomer.This neutralization ratio is calculated according to following formula 3.
[formula 2]
Water soluble composition [weight %]=0.1 * (mean molecule quantity of monomer) * 184.3 * 100 * ([HCl]-[bHCl])/1000/1.0/50.0
[formula 3]
Neutralization ratio [mole %]=(1-([NaOH]-[bNaOH])/([HCl]-[bHCl])) * 100
[remaining monomer]
Except the mixing time in the determination method of said [water soluble composition] was changed to 2 hours by 16 hours; Carry out identical operations and obtain filtrating, try to achieve the amount of remaining monomer contained in the particulate water-absorbing agent of the present invention (remaining acrylic acid (salt)) through analyzing this filtrating.Particularly, through analyzing through high performance liquid chromatography (HPLC) with the filtrating that this operation was obtained, can be in the hope of the remaining monomer in the particulate water-absorbing agent.In addition, remaining monomer is represented with ppm (with respect to particulate water-absorbing agent).
[AAP]
With respect to the expression of the absorbability (AAP) of pressure is to 60 minutes water absorbent rate of 0.90 weight % saline solution under 4.83kPa or 2.0kPa.In addition, AAP is also referred to as adding under 4.83kPa or 2.0kPa sometimes and depresses water absorbent rate.
Use device shown in Figure 1; At the stainless steel 400 purpose wire nettings 101 of bottom weld (mesh is 38 μ m) of the plastic support cylinder 100 of internal diameter 60mm, and under the condition of room temperature (20～25 ℃), humidity 50RH%, spray particulate water-absorbing agent 0.900g on the net equably at this; And loading piston 103 and bear a heavy burden 104 in regular turn above that; And measured the whole weight W a [g] of this determinator, for this piston 103 and bear a heavy burden 104, can the mode that particulate water-absorbing agent applies the heavy burden of 4.83kPa (0.7psi) or 2.0kPa (0.3psi) equably being adjusted; External diameter only is slightly smaller than 60mm, does not produce the gap and does not hinder up and down with support cylinder.
Place the glass filter 106 of diameter 90mm (physics and chemistry is learned nitre and is made the manufacturing of limited company of institute, pore diameter each other: 100～120 μ m), and add the sodium-chloride water solution 108 (20～25 ℃) of 0.90 weight % so that the upper surface of itself and glass filter becomes same plane in the inboard of the culture dish 105 of diameter 150mm., place the filter paper 107 (manufacturing of Japan ADVANTEC limited company, the name of an article: JIS P 3801, No.2, thickness 0.26mm, reservation particle diameter 5 μ m) of a slice diameter 90mm above that, its surface is soaked fully, and remove excess liquid.
Said determinator integral body is placed on the said moistening filter paper, and liquid is absorbed under bearing a heavy burden.After 1 hour, mention determinator integral body, and measure its weight W b [g].Calculate AAP [g/g] according to Wa, Wb and the following formula of foundation then.
[formula 4]
AAP [g/g]=(Wb-Wa)/(weight of particulate water-absorbing agent (0.900g))
[SFC]
The value of the permeability for liquids when SFC (saline solution water conservancy diversion property) is expression water-absorbent besin particles or water absorbing agent swelling.The big more expression of the value of SFC has high more permeability for liquids.Saline solution water conservancy diversion property (SFC) test of putting down in writing according to No. 5849405 specification of United States Patent (USP) and carrying out.
Use represented device among Fig. 2, make the particulate water-absorbing agent 0.900 [g] that is added into equably in the container 40 in artificial urine, depress swelling 60 minutes, write down the gel layer height of gel 44 thereafter in adding of 2.07kPa (0.3psi).Then, depress, make the sodium-chloride water solution 33 of 0.69 weight % under certain hydrostatic pressing, carry out the liquid infiltration to swelling gel 44 from storage tank 31 in adding of 2.07kPa.This SFC test is carried out under room temperature (20～25 ℃).Use computer and balance, will with 20 seconds at interval the amount of liquid through gel layer write down 10 minutes as the function of time.
Flow rate F s (T) through swelling gel 44 (between main particle) is determined divided by the elapsed time [s] [unit: g/s] by gain in weight [g].Certain hydrostatic pressing and the stable time that flow velocity obtained note are made Ts; Only will be used for flow velocity calculating at Ts and the data that obtain between 10 minutes; Use is promptly passed through the initial flow velocity of gel layer in the value of the flow velocity calculating Fs (T=0) of Ts and acquisition between 10 minutes.Fs (T=0) calculates through Fs (T) is extrapolated for T=0 with respect to the result of the least squares method of time.
[formula 5]
SFC[10 -7·cm 3·s·g -1]＝(Fs(t＝0)×L0)/(ρ×A×ΔP)
At this,
Fs (t=0): flow velocity [g/s]
L0: the height of gel layer [cm]
ρ: the density of sodium-chloride water solution (1.003 [g/cm 3])
A: the area (28.27 [cm of the gel layer upside in the groove 41 2])
Δ P: the hydrostatic pressing of gel layer (4920 [dyn/cm 2]).
SFC determinator to shown in Figure 2 is elaborated.
In storage tank 31, insert glass tube 32, the lower end of glass tube 32 is so that the mode of the height more than the 5cm can be kept in the bottom of the swelling gel 44 of the sodium-chloride water solution 33 of 0.69 weight % in the groove 41 is configured.The sodium-chloride water solution 33 of 0.69 weight % in the storage tank 31 is supplied to groove 41 through the L type pipe 34 of band cock 35.Dispose the container 48 that captures the liquid that passes through below the groove 41, trap receptacle 48 is arranged on the flat balance 49.The internal diameter of groove 41 is 6cm, and the bottom surface is provided with the stainless steel wire netting 42 that mesh is 38 μ m.Having in the bottom of piston 46 is enough to hole 47 that liquid is passed through, and permeability good glass filter 45 is installed in the bottom so that particulate water-absorbing agent or its swelling gel do not get into hole 47.Groove 41 is placed on the platform that is used for standing groove, and the table top that contacts with groove is arranged on the wire netting 43 of the stainless steel that does not hinder the liquid infiltration.
In addition, artificial urine is to use the liquid that in pure water 994.25 [g], has added calcium chloride dihydrate 0.25 [g], potassium chloride 2.0 [g], magnesium chloride hexahydrate 0.50 [g], sodium sulphate 2.0 [g], ammonium dihydrogen phosphate (ADP) 0.85 [g], reached diammonium hydrogen phosphate 0.15 [g].
[absorption speed 1 (FSR)]
FSR (absorption speed) is meant that water absorbing agent absorbs the index of the speed of liquid.Preferred absorption speed shows high value.Be used in the water-absorbing body through the water absorbing agent that absorption speed is higher, can obtain liquid absorption speed excellent water-absorbing body.Absorption speed is to measure through following method.
With particulate water-absorbing agent 1.000 ± 0.0005 [g] accurately 4 (Wc [g]) behind weighing to the decimal point, and be added in the glass beaker (diameter 32～34mm, height 50mm) of 25ml with the mode that the upper surface of this particulate water-absorbing agent becomes level.As required, cautiously carry out operations such as tapping beaker, make particulate water-absorbing agent become level.Then, obtain the 0.9 weight % sodium-chloride water solution 20ml amount that is adjusted into 23 ± 2.0 ℃, place the glass beaker of 50ml, and with 4 (Wd [g]) behind gravimetry to the decimal point of this aqueous solution.
Then, this 0.9 weight % sodium-chloride water solution is injected the 25ml beaker that particulate water-absorbing agent is housed rapidly, the moment that contacts with particulate water-absorbing agent with sodium-chloride water solution is a starting point, the beginning minute.From the visual liquid level that has injected the beaker of this sodium-chloride water solution of about 20 ° angle, measure liquid level becomes particulate water-absorbing agent from the aqueous solution time (Th [sec]).Then, measure attached to the weight (We [g]) of having poured into the sodium-chloride water solution (beaker remaining quantity) on the beaker behind the sodium-chloride water solution behind decimal point 4.Try to achieve FSR (absorption speed) [g/g/sec] according to following formula.In addition, 1 sample is measured 3 times, with its mean value as typical value.
[formula 6]
FSR[g/g/sec]＝(Wd-We)/(Th×Wc)
[absorption speed 2 (Vortex)]
In in advance through sodium-chloride water solution (normal saline solution) 1.000 weight portions of 0.90 weight % of adjustment, add as edible blue No. 1 of food additives (CAS numbering: 3844-45-9) 0.02 weight portion, and the liquid temperature is adjusted to 30 ℃.Measure this normal saline solution 50ml; Pour in the beaker (for example learning the beaker that nitre is made the JISR-3503 that is sold) of body diameter 55mm, height 70mm, capacity 100ml according to mutual physics and chemistry; The special teflon of cylinder type (registration mark) system magnet-type stirrer (for example physics and chemistry is learned nitre and made the S type of being sold each other) with length 40mm, thick 8mm stirs under the condition of 600rpm; Drop into the particulate water-absorbing agent 2.0g that is obtained in following embodiment or the comparative example during this period, measure absorption speed (second).Starting point, terminal point are according to the benchmark of putting down in writing among the JIS K 7224 (1996 year) " the absorption speed test method of super absorbent resin is explained orally "; Particulate water-absorbing agent absorbs normal saline solution; Rotational time till the stirring piece of the normal saline solution covering rotation in the mensuration gelation process is (from section; Cover with V-shape), estimate as absorption speed (second).
[logstandard deviation of weight average particle diameter (D50), size distribution (σ ζ) reaches the particle less than 150 μ m]
Weight average particle diameter (D50) is measured according to the method for putting down in writing in No. 2004/069404 book of International Publication.Use mesh be 850 μ m, 710 μ m, 600 μ m, 500 μ m, 425 μ m, 300 μ m, 212 μ m, 150 μ m, 106 μ m, 45 μ m JIS standard screen (JIS Z8801-1 (2000)), or be equivalent to the sieve of these JIS standard screens; Sieve the particulate water-absorbing agent of ormal weight, and retained percentage R is plotted on the logarithmic probability paper.Thus, will be equivalent to R=50 weight % particle diameter and be regarded as weight average particle diameter (D50).
The logstandard deviation of size distribution (σ ζ) representes that with following formula the value of σ ζ small grain size more distributes narrow more.
[formula 7]
σζ＝0.5×In×(X2/X1)
At this,
X1: the particle diameter that is equivalent to R=84.1 [weight %]
X2: the particle diameter that is equivalent to R=15.9 [weight %].
It is that the weight of particle of JIS standard screen (JIS Z8801-1 (2000)) of 150 μ m is with respect to the ratio [weight %] of particulate water-absorbing agent overall weight that the particle of stipulating in the standard screen classification less than 150 μ m [weight %] is meant through mesh.In this manual, also abbreviate " less than the particle [weight %] of 150 μ m " perhaps " 150 μ m pass [%] " as.
[the painted evaluation of particulate water-absorbing agent ((Hunter-Lab) color specification system/L value is found in the Hunter)]
The painted evaluation of particulate water-absorbing agent is to use LabScan (registration mark) XE of upright (Hunter-Lab) manufactured in Hunter and carries out.Impose a condition about what measure, select reflection measurement, use powder/slurry sample of internal diameter 30mm, height 12mm use container, and use powder/slurry with standard circular blank No.2 as standard, use 30 Φ to throw light on and manage.The sample that is equipped with container in the particulate water-absorbing agent of the about 5g of filling.This filling is with the sample that is equipped with vessel filling about about 6 one-tenth.Under the condition of room temperature (20～25 ℃) and humidity 50RH%, utilize said beam splitting type colour difference meter to measure the L value (Lightness: brightness index) on surface.As " brightness index before exposing ", this value is white more greatly more with this value.
In addition, utilize the same measured method of same apparatus, also can measure object color a, the b (colourity) of other yardsticks simultaneously.A/b is more little, is expressed as less colored more and approaching in fact white.Will be after just having made particulate water-absorbing agent, perhaps under the condition below 30 ℃, below the relative humidity 50%RH, preserve 1 year painted evaluation result with the particulate water-absorbing agent of interior time as the initial stage tone.
Then; Fill about 5g particulate water-absorbing agent at said slurry sample in container; And in being adjusted into 70 ± 1 ℃, the constant temperature and humidity machine (minienvironment exerciser, model SH-641 that Ace peck (Espec) limited company makes) of the environment of relative humidity 65 ± 1%, the slurry sample container that is filled with particulate water-absorbing agent is exposed 7 days.This exposure is painted promotion test in 7 days.After the exposure, utilize said beam splitting type colour difference meter to measure L value (Lightness) the a/b value on surface.With this measured value as promote after the test through the time painted.
[foul smell test]
Particulate water-absorbing agent 1 weight portion is added in the beaker of 100ml, and adds 0.9 weight % sodium-chloride water solution, 20 weight portions, thereafter with the sealed by film beaker and 37 ℃ of held 1 hour.Thereafter, carrying out the foul smell official by 10 adult experimenters can test.In the evaluation method,, then be designated as zero if judged result is not have undesirable foul smell and can be used in the hygienic material such as diaper; If judged result is to have undesirable foul smell and be unusable in the hygienic material such as diaper, then be designated as *.For especially undesirable strong foul smell, be designated as * *.
[moisture content]
Take by weighing particulate water-absorbing agent 1.00 [g], place the aluminium cup of bottom surface size, and measure the gross weight W8 [g] of particulate water-absorbing agent and aluminium cup for the about 50mm of diameter.In the baking oven of environment temperature 180 ℃ leave standstill 3 hour carry out drying thereafter.After 3 hours, from baking oven, take out particulate water-absorbing agent and aluminium cup, and in drier, be cooled to room temperature., obtain the gross weight W9 [g] of dried particulate water-absorbing agent and aluminium cup, and try to achieve moisture content according to following formula 8 thereafter.
[formula 8]
Moisture content [weight %]=(W8-W9)/(weight of particulate water-absorbing agent [g]) * 100
[weatherability promotes test] (gel deterioration test 1)
Particulate water-absorbing agent 3.0g is added in the separable flask of quartz system of internal diameter 7.0cm, height 14.0cm, and adds deionized water 57.0g.Thereafter; With the 20 times of swelling gel particles (60g) in the separable flask utilize have 4 from axle central authorities to wing tip the agitator for the flat blade of 3.0cm, wide 1.0cm simultaneously stirs, one side uses the ultraviolet lamp (oxtail motor manufactured, UV-152/1MNSC3-AA06) that metal halide lamp (oxtail motor manufactured, UVL-1500M2-N1) is housed with exposure intensity 60 [mW/cm 2] irradiation ultraviolet radiation 1 minute at room temperature, thereby obtained to have stood the aqueous gel shape water absorbing agent that weatherability promotes test.
Then, in the plastic containers with cover of capacity 250ml, add sodium-chloride water solution 184.3g and the aqueous gel shape water absorbing agent 2.00g of 0.90 weight %, and stirred 16 hours, the solvable composition of extraction aqueous gel shape water absorbing agent with magnetic stirrer.Use 1 filter paper (Japan ADVANTEC limited company, the name of an article: JIS P 3801, No.2, thickness 0.26mm, keep particle diameter 5 μ m) to filter this extract, and with the mixed solution of the sodium-chloride water solution 45.0g of the filtrating 5.0g that obtained and 0.90 weight % as measuring solution.
Then, carry out titration with the NaOH aqueous solution of 0.1N and become 10, carry out titration with the HCl aqueous solution of 0.1N thereafter and become 2.7 until the pH value until the pH value.Try to achieve the titer ([NaOH] ml, [HCl] ml) of this moment.In addition, only the sodium-chloride water solution 184.3g to 0.90 weight % carries out identical titration operation, tries to achieve blank titration amount ([bNaOH] ml, [bHCl] ml).
Under the situation that is aqueous gel shape water absorbing agent of the present invention, based on the mean molecule quantity of monomer whose and the titer that obtains according to said operation, the solvable composition of aqueous gel shape water absorbing agent can be calculated according to following formula 9.In addition, under the mean molecule quantity condition of unknown of monomer, use the neutralization ratio of trying to achieve to calculate the mean molecule quantity of monomer according to titration.This neutralization ratio is to calculate according to following formula 10.
[formula 9]
Water soluble composition [weight %]=0.1 * (mean molecule quantity of monomer) * 184.3 * 100 * ([HCl]-[bHCl])/1000/1.0/50.0
[formula 10]
Neutralization ratio [mole %]=(1-([NaOH]-[bNaOH])/([HCl]-[bHCl])) * 100
The deterioration rate is to calculate by the solvable composition of the solvable composition of particulate water-absorbing agent and aqueous gel shape water absorbing agent and according to following formula 11.
[formula 11]
Deterioration rate [%]=the solvable composition of aqueous gel shape water absorbing agent)-{ the solvable composition of particulate water-absorbing agent }
[urine patience test] (gel deterioration test 2)
Particulate water-absorbing agent 1 weight portion is added in the 250ml plastic containers with cover (ridge, temple limited company make Pac-ace), adds simulation artificial urine 25 weight portions, carry out airtight thereafter and under the temperature and time of regulation, make the particulate water-absorbing agent deterioration.Thereafter, 250ml plastic containers with cover are laid across placed 10 minutes, whether flow to the gel of swelling this moment is estimated.In addition, this test is under following 2 deterioration conditions, to implement.
(1) urine patience test (L-ascorbic acid concentrations usually) (gel deterioration test 2-1)
[gel deterioration condition (1)]
The simulation artificial urine: the L-ascorbic acid concentrations is the normal saline solution of 0.005 weight %
Degradation temperatures: 37 ℃
The deterioration time: 24 hours
(2) urine patience test (1000 times of L-ascorbic acid) (gel deterioration test 2-2)
[gel deterioration condition (2)]
The simulation artificial urine: the L-ascorbic acid concentrations is the normal saline solution of 5 weight %
Degradation temperatures: 90 ℃
The deterioration time: 1 hour
[dust mensuration]
The Heubach Dustmeter2000 that uses limited company of Seishin Entpr Co., Ltd. (Seishin Enterprise) to make measures the amount of dust from particulate water-absorbing agent under following condition.
Condition determination
Operating environment: 18～22 ℃/45～55RH%
Sample: 100.00g
Model: Type (I) (horizontal)
Rotating speed: 30 [R/min]
Air-flow: 20.0 [L/min]
Time: 60min (because capping 30 minutes, so carried out 2 times 30 minutes)
Catcher/filter: filter paper (GC90 that ADVANTEC makes)
Weight through the filter paper of instrumentation mensuration after 10 minutes increases part [mg], tries to achieve the amount of dust from particulate water-absorbing agent according to following formula.
[formula 12]
Amount of dust [mg/kg]={ weight of measuring the filter paper after 10 minutes increases part } * 10
[in the particulate water-absorbing agent contained p methoxy phenol]
Through to except the mixing time in the evaluation method of said [solvable composition] was changed to 1 hour from 16 hours; All carry out identical operations and obtain filtrating, filtrate and try to achieve p methoxy phenol contained in the particulate water-absorbing agent of the present invention through analyzing this then.Particularly,, the filtrating that obtains via this operation is analyzed with high performance liquid chromatography (HPLC), thus can be in the hope of the p methoxy phenol in the particulate water-absorbing agent.In addition, p methoxy phenol is expressed with ppm (with respect to particulate water-absorbing agent).
[in the particulate water-absorbing agent contained reducing agent (sodium hydrogensulfite)]
About reducing agent contained in the particulate water-absorbing agent of the present invention, the assay method of illustration sodium hydrogensulfite.In the beaker of 200ml, add pure water 50g and particulate water-absorbing agent 0.5g and placed 1 hour.Then, after adding methyl alcohol 50g, add making peacock green 2mmol be dissolved in the solution 2.5g in the following eluent.This solution stirring is filtered after about 30 minutes, try to achieve the amount of reducing agent contained in the particulate water-absorbing agent through filtrating with high performance liquid chromatography (HPLC) analysis.In addition, eluent is adjusted into the ratio of methyl alcohol 400ml, n-hexane 6ml, 0.0M-2-N-morpholinyl-b sodium salt 100ml.In addition, calibration curve can be through adding (spike) reducing agent and analyzing and make in the particulate water-absorbing agent that does not contain reducing agent.
[in the particulate water-absorbing agent contained chelating agent]
Except the mixing time in the evaluation method of said [solvable composition] was changed to 1 hour from 16 hours; Other all carry out identical operations; And obtain filtrating, through this filtrating is analyzed, can try to achieve chelating agent contained in the particulate water-absorbing agent of the present invention.Particularly,, the filtrating that gets via this operation is analyzed, can be tried to achieve the chelating agent in the particulate water-absorbing agent thus with high performance liquid chromatography (HPLC).In addition, chelating dosage is expressed with ppm (with respect to particulate water-absorbing agent).In addition, calibration curve can be through adding (spike) chelating agent and analyzing and process in the particulate water-absorbing agent that does not contain chelating agent.
[embodiment 1-1]
Use the device shown in Figure 3 of record in No. the 7265190th, the United States Patent (USP), make aqueous gel shape cross-linked polymer according to following method.
At first, make the monomer solution (1-1) comprise following composition: with the content of p methoxy phenol be adjusted into 70ppm acrylic acid 35.2 weight portions, 48 weight % sodium hydrate aqueous solutions, 11.7 weight portions, polyethyleneglycol diacrylate (average ethylene oxide unit number: n=9) 0.23 weight portion, (be called for short: DTPA3Na) aqueous solution 0.22 weight portion, and deionized water 33.6 weight portions as 1 weight % diethylenetriamine pentaacetic acid trisodium of chelating agent.
Then, use constant displacement pump to be supplied to polymerization procedure continuously the said monomer solution (1-1) that is adjusted into 40 ℃.Before importing belt polymerization machine, 48 weight % sodium hydrate aqueous solutions (ferrous components content is 0.7ppm (with respect to the NaOH solid constituent)), 177 weight portions are mixed continuously through the streamline mixing.At this moment, monomer temperature rises to 86 ℃ because of the heat of neutralization.
Then, mix through streamline 4 weight % sodium persulfate aqueous solutions, 1.38 weight portions are mixed continuously, the mode that the more continuous mixture (1-1) that is obtained is about 7.5mm with thickness is supplied to two ends to be had on the planar band of rib.Carry out polymerization in 3 minutes continuously, obtain aqueous gel shape cross-linked polymer (1-1).
Then, said aqueous gel shape cross-linked polymer (1-1) is about 1.5mm with the meat grinder sectionalization of aperture 22mm.This gel through sectionalization is spread out on the porous plate that moves that is placed on the continuous ventilating band drier, and drying is 30 minutes under 185 ℃, obtains dry polymer (1-1).After utilizing roller mill pulverize to obtain dry polymer (1-1), be that the screening plant of the metallic sieve of 710 μ m and 175 μ m sieves, obtain the water-absorbing resins powder (1-1) of 175～710 μ m through aforesaid operations to have mesh.
With respect to water-absorbing resins powder (1-1) 100 weight portions that obtained; Mix equably and comprise 1; Behind the surface crosslinking agent of the mixed liquor of 4-butanediol 0.3 weight portion, propane diols 0.6 weight portion, deionized water 3.0 weight portions; Again with mixture 208 ℃ of following heat treated 40 minutes, obtain surface-crosslinked water-absorbing resins powder (1-1) through aforesaid operations.
After surface-crosslinked water-absorbing resins powder (1-1) cooling that is obtained; With respect to surface-crosslinked water-absorbing resins powder (1-1) 100 weight portions; Interpolation also mixes 30 weight % aqueous solution of sodium bisulfite, 1.66 weight portions, obtains particulate water-absorbing agent presoma (1-1).Then, the particulate water-absorbing agent presoma (1-1) that is obtained was placed 30 minutes in 60 ℃ air drier, making it thereafter is the JIS standard screen of 710 μ m through mesh, obtains particulate water-absorbing agent (1-1) through aforesaid operations.The moisture content of the particulate water-absorbing agent that is obtained (1-1) is 1.8 weight %.The physical property of the particulate water-absorbing agent that is obtained (1-1) is documented in the table 1.
[embodiment 1-2]
Except the addition with 30 weight % aqueous solution of sodium bisulfite of embodiment 1-1 record changes to 3.33 weight portions from 1.66 weight portions, all obtain particulate water-absorbing agent (1-2) according to the mode identical with embodiment 1-1.The physical property of the particulate water-absorbing agent that is obtained (1-2) is documented in the table 1.
[embodiment 1-3]
Except the addition with 30 weight % aqueous solution of sodium bisulfite of embodiment 1-1 record changes to 0.166 weight portion from 1.66 weight portions; All obtain water absorbing agent with the mode identical with embodiment 1-1; In these water absorbing agent 100 weight portions; Further add and mix 50 weight % sodium lactate aqueous solutions, 0.6 weight portion, obtain particulate water-absorbing agent presoma (1-3).Then, the particulate water-absorbing agent presoma (1-3) that is obtained was placed 30 minutes in 60 ℃ air drier, making it thereafter is the JIS standard screen of 710 μ m through mesh, obtains particulate water-absorbing agent (1-3) through aforesaid operations.The moisture content of the particulate water-absorbing agent that is obtained (1-3) is 2.0 weight %.The physical property of the particulate water-absorbing agent that is obtained (1-3) is documented among the table 1-1.
[embodiment 1-4]
Except the addition with 30 weight % aqueous solution of sodium bisulfite among the embodiment 1-3 changes to 1.66 weight portions from 0.166 weight portion; And the addition of 50 weight % sodium lactate aqueous solutions is changed to beyond 0.1 weight portion from 0.6 weight portion, all obtain particulate water-absorbing agent (1-4) with the mode identical with embodiment 1-3.The physical property of the particulate water-absorbing agent that is obtained (1-4) is documented among the table 1-1.
[embodiment 1-5]
Except the addition with 30 weight % aqueous solution of sodium bisulfite among the embodiment 1-3 changes to 1.66 weight portions from 0.166 weight portion, all obtain particulate water-absorbing agent (1-5) with the mode identical with embodiment 1-3.The physical property of the particulate water-absorbing agent that is obtained (1-5) is documented in the table 1.
[embodiment 1-6]
With respect to surface-crosslinked water-absorbing resins powder (1-1) 100 weight portions among the embodiment 1-1; Interpolation also mixes 30 weight % aqueous solution of sodium bisulfite, 0.33 weight portion; Further mixed liquor 1.22 weight portions of hybrid packet sulfur acid aluminum water solution (being scaled 8 weight % with aluminium oxide) 0.9 weight portion, 60 weight % sodium lactate aqueous solution 0.30 weight portions and propane diols 0.02 weight portion equably obtain particulate water-absorbing agent presoma (1-6) thus.Then, the particulate water-absorbing agent presoma (1-6) that is obtained was placed 30 minutes in 60 ℃ air drier, making it thereafter is the JIS standard screen of 710 μ m through mesh, obtains particulate water-absorbing agent (1-6) thus.The physical property of the particulate water-absorbing agent that is obtained (1-6) is documented in the table 1.
[embodiment 1-7]
Use the device of putting down in writing in No. 7265190 specification of United States Patent (USP) shown in Figure 3, make aqueous gel shape cross-linked polymer according to following method.
At first, make the monomer solution (1-7) comprise following proportion of composing: the content of p methoxy phenol is adjusted to acrylic acid 35.2 weight portions, 48 weight % sodium hydrate aqueous solutions, 11.7 weight portions, polyethyleneglycol diacrylate of 70ppm, and (average ethylene oxide unit number: n=9) 0.23 weight portion, 31% ethylenediamine tetraacetic (methylene phosphonic acid), five sodium (are called for short: EDTMPA5Na) aqueous solution 0.03 weight portion, and deionized water 33.6 weight portions.
Then, use constant displacement pump to be supplied to polymerization procedure continuously the said monomer solution (1-7) that is adjusted to 40 ℃.Before importing belt polymerization machine, 48 weight % sodium hydrate aqueous solutions, 17.7 weight portions are mixed continuously through the streamline mixing.At this moment, monomer temperature rises to 86 ℃ because of the heat of neutralization.Then, mix through streamline 4 weight % sodium persulfate aqueous solutions, 1.38 weight portions are mixed continuously, and the mode that the continuous mixture (1-7) that is obtained is about 7.5mm with thickness is supplied to two ends has on the planar band of rib.Carry out polymerization in 3 minutes continuously, obtain aqueous gel shape cross-linked polymer (1-7).
Then, said aqueous gel shape cross-linked polymer (1-7) is about 1.5mm with the meat grinder sectionalization of aperture 22mm.This gel through sectionalization is spread out on the mobile porous plate that is placed on the continuous ventilating band drier, and drying is 30 minutes under 185 ℃, and obtains dry polymer (1-7).After utilizing roller mill pulverize to obtain dry polymer (1-7), be that the screening plant of the metallic sieve of 710 μ m and 175 μ m sieves to have mesh, obtaining particle diameter thus is the water-absorbing resins powder (1-7) of 175～710 μ m.
With respect to water-absorbing resins powder (1-7) 100 weight portions that obtained; Mix equably and comprise 1; The surface crosslinking agent of the mixed liquor of 4-butanediol 0.3 weight portion, propane diols 0.6 weight portion and deionized water 3.0 weight portions; Thereafter with mixture 208 ℃ of following heat treated 40 minutes, obtain surface-crosslinked water-absorbing resins powder (1-7) thus.
Cooling obtains surface-crosslinked water-absorbing resins powder (1-7); Thereafter with respect to surface-crosslinked water-absorbing resins powder (1-7) 100 weight portions; Add equably and mix mixed liquor 1.23 weight portions that comprise 30 weight % aqueous solution of sodium bisulfite, 1.66 weight portions, 30 weight % aluminum sulfate aqueous solutions (being scaled 8 weight %), 0.9 weight portion, 60 weight % sodium lactate aqueous solution 0.30 weight portions and propane diols 0.03 weight portion, obtain particulate water-absorbing agent presoma (1-7) thus with aluminium oxide.Then, the particulate water-absorbing agent presoma (1-7) that is obtained was placed 30 minutes in 60 ℃ air drier, making it thereafter is the JIS standard screen of 710 μ m through mesh, obtains particulate water-absorbing agent (1-7) thus.The physical property of the particulate water-absorbing agent that is obtained (1-7) is documented in the table 1.
[embodiment 1-8]
The commercially available acrylic acid that will be obtained through the gas phase catalytic oxidation is (superfine with the pure medicine of light, reagent; Contain p methoxy phenol 200ppm) be supplied at the bottom of the tower of high-boiling-point impurity knockout tower with 50 sections no rib porous plates; Reflux ratio is made as 1 distills; Further carry out redistillation, obtain to comprise the above purifying propenoic acid (1-8) that reaches trace impurity (being mainly water) of acrylic acid 99 weight % thus.P methoxy phenol amount in the purifying propenoic acid (1-8) is ND (less than 1ppm).
Through interpolation 15ppm p methoxy phenol in purifying propenoic acid (1-8), and obtained adjustment acrylic acid (1-8).
Use the device of putting down in writing in No. 7265190 specification of United States Patent (USP) shown in Figure 3, make aqueous gel shape cross-linked polymer according to following method.
At first, make the monomer solution (1-8) comprise following proportion of composing: (average ethylene oxide unit number: n=9) 0.23 weight portion, 31 weight % ethylenediamine tetraacetics (methylene phosphonic acid), five sodium (are called for short: EDTMPA5Na) aqueous solution 0.03 weight portion, and deionized water 33.6 weight portions for said adjustment acrylic acid (1-8) 35.2 weight portions, 48 weight % sodium hydrate aqueous solutions (ferrous components content is 0.7ppm (with respect to the NaOH solid constituent)), 11.7 weight portions, polyethyleneglycol diacrylate.
Then, said monomer solution (1-8) is adjusted into 40 ℃, and with the constant displacement pump continuous feed.Through the streamline mixing 48 weight % sodium hydrate aqueous solutions, 17.7 weight portions are mixed in this monomer solution (1-8) continuously.At this moment, the temperature of monomer rises to 86 ℃ because of the heat of neutralization.Then, through the streamline mixing 4 weight % sodium persulfate aqueous solutions, 1.38 weight portions are mixed continuously.This is mixed mode that the continuous mixture (1-8) obtained is about 7.5mm with thickness be supplied to two ends and have on the planar band of rib through streamline, and carry out polymerization in 3 minutes continuously, obtain aqueous gel shape cross-linked polymer (1-8).
Then, said aqueous gel shape cross-linked polymer (1-8) is about 1.5mm with the meat grinder sectionalization of aperture 22mm.This gel through sectionalization is spread out on the mobile porous plate that is placed on the continuous ventilating band drier, obtained dry polymer (1-8) down in dry 30 minutes at 185 ℃.After the dry polymer that is obtained (1-8) pulverized with roller mill, be that the screening plant of the metallic sieve of 710 μ m and 175 μ m sieves, obtain the water-absorbing resins powder (1-8) of 175～710 μ m thus to have mesh.
With respect to water-absorbing resins powder (1-8) 100 weight portions that obtained; Mix equably and comprise 1; The surface crosslinking agent of the mixed liquor of 4-butanediol 0.3 weight portion, propane diols 0.6 weight portion and deionized water 3.0 weight portions; Mixture 208 ℃ following heat treated 40 minute, thus obtained surface-crosslinked water-absorbing resins powder (1-8) thereafter.
Make surface-crosslinked water-absorbing resins powder (1-8) cooling that is obtained; Thereafter with respect to surface-crosslinked water-absorbing resins powder (1-8) 100 weight portions; Add equably and mix and comprise 30 weight % aqueous solution of sodium bisulfite 1.66 weight portions and aluminum sulfate aqueous solution (in the aluminium oxide 8 weight % that convert) 0.9 weight portion, 60 weight % sodium lactate aqueous solutions, 0.50 weight portion, and mixed liquor 1.44 weight portions of propane diols 0.04 weight portion, obtain particulate water-absorbing agent presoma (1-8) thus.Then, the particulate water-absorbing agent presoma (1-8) that is obtained was placed 30 minutes in 60 ℃ air drier, thereafter, making it is the JIS standard screen of 710 μ m through mesh, obtains particulate water-absorbing agent (1-8) thus.The physical property of the particulate water-absorbing agent that is obtained (1-8) is documented in the table 1.
[embodiment 1-9]
Through interpolation 200ppm p methoxy phenol in the purifying propenoic acid (1-8) of embodiment 1-8 record, and obtained adjustment acrylic acid (1-9).
Except using adjustment acrylic acid (1-9) to replace beginning to carry out surface-crosslinked processing with embodiment 1-8 auto polymerization likewise the adjustment acrylic acid (1-8), obtain surface-crosslinked water-absorbing resins powder (1-9) thus.
With surface-crosslinked water-absorbing resins powder (1-9) cooling that is obtained; Thereafter with respect to surface-crosslinked water-absorbing resins powder (1-9) 100 weight portions; Interpolation also mixes 30 weight % aqueous solution of sodium bisulfite, 1.66 weight portions, obtains particulate water-absorbing agent presoma (1-9).Then, the particulate water-absorbing agent presoma (1-9) that is obtained was placed 30 minutes in 60 ℃ air drier, making it thereafter is the JIS standard screen of 710 μ m through mesh, obtains particulate water-absorbing agent (1-9) thus.The moisture content of the particulate water-absorbing agent that is obtained (1-9) is 1.8 weight %.The physical property of the particulate water-absorbing agent that is obtained (1-9) is documented in the table 1.
[comparative example 1-1]
Do not use chelating agent, in addition, the addition of 30 weight % aqueous solution of sodium bisulfite changed to 0.166 weight portion from 1.66 weight portions, in addition, all according to embodiment 1-1 in the identical mode of method put down in writing obtain comparison particulate water-absorbing agent (1-1).The physical property of the comparison particulate water-absorbing agent (1-1) that is obtained is documented in the table 1.
[comparative example 1-2]
Except not using 30 weight % aqueous solution of sodium bisulfite, all obtain comparison particulate water-absorbing agent (1-2) according to the identical mode of method with embodiment 1-1 record.The physical property of the comparison particulate water-absorbing agent (1-2) that is obtained is documented in the table 1.
[comparative example 1-3]
With respect to comparison particulate water-absorbing agent (1-2) 100 weight portions that obtained among the comparative example 1-2; Hybrid packet sulfur acid aluminum water solution (being scaled 8 weight % with aluminium oxide) 0.9 weight portion, 60 weight % sodium lactate aqueous solutions, 0.30 weight portion, and mixed liquor 1.22 weight portions of propane diols 0.02 weight portion obtain relatively particulate water-absorbing agent presoma (1-3) thus equably.
Then, the comparison particulate water-absorbing agent presoma (1-3) that is obtained was placed 30 minutes in 60 ℃ air drier, making it thereafter is the JIS standard screen of 710 μ m through mesh, obtains relatively particulate water-absorbing agent (1-3) thus.The physical property of the comparison particulate water-absorbing agent (1-3) that is obtained is documented in the table 1.
[comparative example 1-4]
Except the content with the p methoxy phenol in the acrylic acid of embodiment 1-1 record changes to the 270ppm from 70ppm; All obtain comparison surface cross-linking of water-absorbing resin powder (1-4) according to the mode identical with embodiment 1-1; With respect to these comparison surface cross-linking of water-absorbing resin powder (1-4) 100 weight portions; Add equably and mix 30 weight % aqueous solution of sodium bisulfite, 0.166 weight portion, obtain relatively particulate water-absorbing agent presoma (1-4).Then, the comparison particulate water-absorbing agent presoma (1-4) that is obtained was placed 30 minutes in 60 ℃ air drier, making it thereafter is the JIS standard screen of 710 μ m through mesh, obtains relatively particulate water-absorbing agent (1-4) thus.The physical property of the comparison particulate water-absorbing agent (1-4) that is obtained is documented in the table 1.
[comparative example 1-5]
With reference to patent documentation 29 or embodiment 4,5, disclose the more comparative example of chelating agent.Promptly; (be called for short: DTPA3Na) addition of the aqueous solution changes to 25.8 weight portions from 0.22 weight portion with 1 weight % diethylenetriamine pentaacetic acid trisodium; The addition of deionized water is changed to 8.0 weight from 33.6 weight portions; And the addition of 30 weight % aqueous solution of sodium bisulfite is changed to 3.33 weight portions from 1.66 weight portions; Carry out identical operations in addition, obtain to contain the comparison particulate water-absorbing agent (1-5) of chelating agent 6000ppm and inorganic reducing agent 1.0 weight % with embodiment 1-1.The moisture content of the comparison particulate water-absorbing agent (1-5) that is obtained is 1.9 weight %.The physical property of the comparison particulate water-absorbing agent (1-5) that is obtained is documented in the table 1.
[embodiment 1-10]
Except the adjustment acrylic acid (1-9) that the adjustment acrylic acid among the embodiment 1-7 is changed to embodiment 1-9 record, obtain particulate water-absorbing agent (1-10) through the mode identical with embodiment 1-7.The physical property of the particulate water-absorbing agent that is obtained (1-10) is documented in the table 1.
[embodiment 1-11]
Except the adjustment acrylic acid with embodiment 1-7 record changes to the adjustment acrylic acid (1-8) of embodiment 1-8 record, obtain particulate water-absorbing agent (1-11) through the mode identical with embodiment 1-7.The physical property of the particulate water-absorbing agent that is obtained (1-11) is documented in the table 1.
[embodiment 1-12]
Except (be called for short: EDTMPA5Na) addition of the aqueous solution changes to 0.07 weight portion from 0.03 weight portion, obtains particulate water-absorbing agent (1-12) through the mode identical with embodiment 1-11 with 31 weight % ethylenediamine tetraacetics (methylene phosphonic acid), five sodium.The physical property of the particulate water-absorbing agent that is obtained (1-12) is documented in the table 1.
[embodiment 1-13]
Particulate water-absorbing agent (1-1) to embodiment 1-1 record carries out atmospheric exposure test, and the result of the deterioration rate that is obtained is documented in the table 2.
[comparative example 1-6]
Except using the p methoxy phenol that in embodiment 1-8, is obtained as adding the relatively adjustment acrylic acid (1-6) that p methoxy phenol 1ppm obtains in the purifying propenoic acid (1-8) of ND; Replace the content with p methoxy phenol of embodiment 1-1 record to be adjusted into beyond the acrylic acid of 70ppm; All likewise carry out polymerization, obtain relatively particulate water-absorbing agent (1-6) according to the method for putting down in writing among the embodiment 1-1.The p methoxy phenol of the comparison particulate water-absorbing agent (1-6) that is obtained is ND (less than 1ppm).Use the comparison particulate water-absorbing agent (1-6) that is obtained to carry out atmospheric exposure test, the result is documented in the table 2.
[embodiment 1-14]
Measure particulate water-absorbing agent (1-1), (1-8), the remaining p methoxy phenol of (1-9), remaining chelating agent, remaining sodium hydrogensulfite, the result is documented in the table 3.
[comparative example 1-7]
Measure relatively particulate water-absorbing agent (1-4), the remaining p methoxy phenol of (1-5), remaining chelating agent, remaining sodium hydrogensulfite, the result is documented in the table 3.
[table 1]
Figure BDA0000148091730000701
[table 2]
Figure BDA0000148091730000711
[table 3]
[comparative example 1-8]
As stated, do not disclose the p methoxy phenol of the inorganic microparticle of water-insoluble, specified quantitative, specific moisture content (3～15 weight %) in the patent documentation 17 (No. 1645596 specification of European patent).In addition, disclosed (paragraph [0019] [embodiment 6]) (butyl etc.) alkyl hydroxy methyl phenyl ethers anisole etc. in the patent documentation 17 as the organic oxidation-resistant agent.At this, in order to show conspicuousness of the present invention, the embodiment 6 according to patent documentation 17 and corresponding No. 3940103 communique of Japanese stating Patent thereof obtains relatively particulate water-absorbing agent (1-8).
Particularly; In the polyethylene can of capacity 2L; Add butylated hydroxyanisole (BHA) 1 weight portion that discloses in water-absorbing resins 100 weight portions, natrium nitrosum 3 weight portions, HEDTA trisodium (the particle ratio below the particle diameter 106 μ m is 89 weight %) 1.5 weight portions and the patent documentation 17 that is obtained in the manufacturing example of said stating Patent communique; Mixer to possess agitator mixed 1 hour, obtained relatively particulate water-absorbing agent (1-8).
(claim again: 19.0g normal saline solution) makes 20 times of its swellings in comparison particulate water-absorbing agent (1-8) 1.0g that is obtained, to add 0.9 weight % sodium-chloride water solution.Then, be added in the plastic container with cover of capacity 120ml, and in the baking oven of 37 ℃ of environment temperatures, placed 3 hours, obtain relatively particulate water-absorbing agent (1-8) of swelling through the comparison particulate water-absorbing agent (1-8) that will be somebody's turn to do through swelling.20 times of swelling gels of the comparison particulate water-absorbing agent (1-8) that is obtained according to patent documentation 17 are colored as yellow.
Then, use the LabScanXE of upright (Hunter-Lab) manufactured in Hunter to measure the relatively tone (initial stage tone) of 20 times of swelling gels of particulate water-absorbing agent (1-8).To measure the result is shown in Table 4.
In addition, to measure be in the white propylene container made of diameter 5.0cm, height 1.2cm, to fill examined object matter and carry out to tone.In addition, as blank, the tone of said white propylene container made is the L value: 54.73, a value: 0.16, b value :-0.50.
In addition; To powder according to the comparison particulate water-absorbing agent (1-8) of patent documentation 17 (butylated hydroxyanisole (BHA) 1 weight portion); Likewise carry out painted promotion test (70 ℃, RH65%) in 7 days with embodiment 1-1～1-12 and table 2 thereof; Keep substantial white with respect to particulate water-absorbing agent of the present invention, relatively particulate water-absorbing agent (1-8) is colored as orange.Likewise measure tone (through the time tone).To measure the result is shown in Table 5.In addition, the comparison particulate water-absorbing agent (1-8) after the painted promotion test in 7 days discharges foreign odor.
[embodiment 1-15]
To the particulate water-absorbing agent (1-1) that is obtained among the embodiment 1-1,, obtain 20 times of swelling gels (1-15) of particulate water-absorbing agent (1-1) through carrying out identical operations with comparative example 1-8.About the swelling particulate water-absorbing agent (1-15) that is obtained; Said relatively 20 times of swelling gels variable color of particulate water-absorbing agent (1-8) according to patent documentation 17 (butylated hydroxyanisole (BHA) 1 weight portion) is yellow; With respect to this, 20 times of swelling gels (1-15) of particulate water-absorbing agent (1-1) still are transparent aqueous gel.
To the tone of 20 times of swelling gels (1-15) of this particulate water-absorbing agent (1-1), also likewise measure with comparative example 1-8.To measure the result is shown in Table 4.
[embodiment 1-16]
Measure absorption speed (FSR) to the moisture content that is obtained among the embodiment 1-1 1.8 weight % particulate water-absorbing agents (1-1), the result is 0.23 [g/g/sec].In order to study the influence of moisture content, through interpolation water 10 weight % in particulate water-absorbing agent (1-1), and further under 80 ℃, carry out drying under reduced pressure, obtain the particulate water-absorbing agent (1-15) of moisture content 3.9 weight %.
The absorption speed (FSR) of the particulate water-absorbing agent (1-15) of the said moisture content that obtains 3.9 weight % is 0.27 [g/g/sec], learns through improving moisture content, especially makes moisture content become 3～15 weight %, and the absorption speed of water absorbing agent is improved.Below, the manufacturing approach that makes moisture content become 3～15 weight % water absorbing agents is described through embodiment 3-1～embodiment 3-13.
[table 4]
[table 5]
(summary)
Said embodiment 1-1～1-16 and table 1～table 5 relate to the manufacturing approach 1 of particulate water-absorbing agent of the present invention; It is a kind of manufacturing approach of the particulate water-absorbing agent that may further comprise the steps: with the acrylic acid (salt) that contains 10～200ppm methoxybenzene phenols is the drying steps of the polymerization procedure of the monomer solution of principal component, aqueous gel shape cross-linked polymer that polymerization gets, surface-crosslinked step, and the interpolation step of 0.001～0.5 weight % chelating agent, it is characterized in that: the interpolation step of after surface-crosslinked step, carrying out inorganic reducing agent.
Shown in said embodiment 1-1～1-13; Water absorbing agent of the present invention through the time tone and initial stage tone excellent; Through after surface-crosslinked step, carrying out the interpolation step of inorganic reducing agent; Even if be low-water-content less than 3 weight %, or be under high temperature surface-crosslinked (150～250 ℃) less than the low-water-content of 3 weight %, the water absorbing agent that is obtained does not have undesirable foul smell yet.This foul smell and its are merely said so and are used the foul smell of raw material (especially inorganic reducing agent); Not equal to be water-absorbing resins and the inorganic reducing agent compound foul smell in manufacturing step; Though its generation can't expect, find this new problem among the present invention, and shown in preceding text with its solution.In addition, only contain among any the comparative example 1-1～1-3 in chelating agent and the inorganic reducing agent, even if the metoxyphenol amount in the scope of 5～60ppm, through the time tone also relatively poor.The metoxyphenol amount is that extraneous comparative example 1-4 (in water absorbing agent, being 82ppm), the comparative example 1-6 of 5～60ppm (is 1ppm in acrylic acid; In the water absorbing agent that is obtained for ND) in through the time tone relatively poor, perhaps weatherability (with reference to the solvable composition in promotion test back of table 2) is relatively poor.In addition; Not only do not disclose specific moisture content of the present invention (3～15 weight %) in the patent documentation 29; And there is not announcement to contain the compound of phosphorus atoms or the specific addition that sulphur is reducing agent (being 0.001～0.5 weight %, 0.001～0.1 weight %); Disclosed interpolation 1-hydroxy ethylene-1 among the embodiment 5 of patent documentation 29,1-di 2 ethylhexyl phosphonic acid 1.0 weight % have likewise disclosed use 1-hydroxy ethylene-1 among the embodiment 4; The 1-di 2 ethylhexyl phosphonic acid adds up to 2.0 weight %; But shown in comparative example 1-5, find that the use-case that makes of chelating agent that this surpasses 0.5 weight % causes harmful effect to the water absorbing agent that obtained painted on the contrary, the present invention has solved the problems referred to above through moisture content is controlled at particular range.In addition, shown in embodiment 1-16, the specific amount of moisture in the water absorbing agent is because the raising of absorption speed also becomes better.
Promptly; Shown in said embodiment; Novel water absorbing agent of the present invention is with the particulate water-absorbing agent of polyacrylic acid (salt) water-absorbent resin as principal component; It contains chelating agent and inorganic reducing agent, and the content of this chelating agent is 0.001～0.5 weight %, and the content of methoxybenzene phenols is 5～60ppm.Of the present invention novel water absorbing agent shown in the said embodiment preferably do not have absorbent rate under pressure (CRC) be 25 [g/g] above, add that to depress water absorbent rate (AAP4.83kPa) be more than 20 [g/g], and saline solution water conservancy diversion property (SFC) is 30 [* 10 -7Cm 3Sg -1] more than.In addition, though not record in the table, the FSR of this water absorbing agent is the scope of about 0.25 (± 0.02) [g/g/sec], and in addition, remaining monomer also is below the 400ppm, and weight average particle diameter (D50) also is about 360～380 μ m.In addition, this water absorbing agent preferably also contains the alpha-hydroxy carboxylic acid compounds compound.In addition, also contain multivalent metal salt and/or cation property copolymer.These water absorbing agents do not have the initial stage and through the time painted; And be white; And permeability for liquids (SFC), absorbent rate under pressure (AAP) are also higher, so even if be used in the less high concentration paper nappy of paper pulp, also have high liquid diffusivity and low contrary (Re-wet) property of oozing; And there is not the coloring problem that causes by water absorbing agent, thereby good paper nappy can be provided.
[embodiment 2-1]
In the kneader that possesses 2 Sigma's type blades, preparation comprises PAA, acrylic acid and the water that utilizes the NaOH contain ferrous components 0.7ppm to neutralize, and the concentration of monomer is 38 weight %, and neutralization ratio is the monomer solution of 75 moles of %.In addition, acrylic acid is to use the acrylic acid that the content of p methoxy phenol is adjusted into 70ppm.In this monomer solution, dissolve polyethyleneglycol diacrylate (average ethylene glycol unit number: 9) as internal crosslinking agent with the mode that becomes 0.045 mole of % (with respect to monomer).
Then, in said monomer solution, be blown into nitrogen, reduce the dissolved oxygen in this monomer solution, simultaneously integral body in the reaction vessel is carried out nitrogen replacement.Then; One side makes 2 Sigma type blades rotation one sides that the temperature of monomer solution is adjusted into 22 ℃, thereafter so that sodium peroxydisulfate becomes 0.12 [g/mol] (with respect to monomer), the mode that makes the L-ascorbic acid become 0.005 [g/mol] (with respect to monomer) is added to polymerization initiator.
Owing to get started polymerization, monomer solution forms white casse, so blade stops the rotation.After polymerization temperature arrives 50 ℃, make the blade rotation once more, in kneader, under agitation proceed polymerization, after about 50 minutes, obtain the aqueous gel shape cross-linked polymer (2-1) that weight average particle diameter is about 2mm.
The aqueous gel shape cross-linked polymer (2-1) that is obtained was utilized air drier dry about 60 minutes under 170 ℃.Then; Utilize roller mill pulverizer to pulverize dry thing; And to use mesh be that the sieve of 850 μ m and 150 μ m carries out classification (removing the screenings of sieve of oversize and 150 μ m of the sieve of 850 μ m), obtains the water-absorbent besin particles (2-1) of moisture content 3 weight %, weight average particle diameter 370 μ m.In the water-absorbent besin particles that is obtained (2-1), not comprising particle diameter in fact is the above particles of 850 μ m, and contains the fine powder less than 150 μ m of 2 weight %.
With respect to the water-absorbent besin particles that is obtained (2-1) 100 weight portions; Mix equably and comprise ethylene glycol diglycidylether 0.025 weight portion, 1; The surface crosslinking agent of the mixed liquor of 4-butanediol 0.3 weight portion, propane diols 0.5 weight portion, deionized water 3.0 weight portions; Thereafter with mixture 208 ℃ of following heat treated 40 minutes, obtain surface-crosslinked water-absorbing resins powder (2-1) thus.
With surface-crosslinked water-absorbing resins powder (2-1) cooling that is obtained; Thereafter with respect to surface-crosslinked water-absorbing resins powder (2-1) 100 weight portions; Interpolation also mixes 30 weight % aqueous solution of sodium bisulfite 1.66 weight portions and 45 weight % diethylenetriamine pentaacetic acid sodium water solutions, 0.44 weight portion, obtains particulate water-absorbing agent presoma (2-1).Then, the particulate water-absorbing agent presoma (2-1) that is obtained was placed 30 minutes in 60 ℃ air drier, making it thereafter is the JIS standard screen of 810 μ m through mesh.And then; With respect to surface-crosslinked water-absorbing resins powder (2-1) 100 weight portions; Add and mixed silica (trade name: Aerosil200CF-5, Japanese Aerosil limited company make) 0.3 weight portion obtains particulate water-absorbing agent (2-1) thus as the inorganic microparticle of white water-insoluble.The physical property of the particulate water-absorbing agent that is obtained (2-1) is documented in the table 6.In addition, the L of silica, a, b are respectively 93.6 ,-0.8 ,-3.6, and be whiter than water-absorbing resins.
[embodiment 2-2]
Except the addition with respect to the silica of surface-crosslinked water-absorbing resins powder (2-1) 100 weight portions among the embodiment 2-1 is changed to 1.0 weight portions from 0.3 weight portion, all obtain particulate water-absorbing agent (2-2) according to the mode identical with embodiment 2-1.The physical property of the particulate water-absorbing agent that is obtained (2-2) is documented in the table 6.
[embodiment 2-3]
Except the addition with respect to the silica of surface-crosslinked water-absorbing resins powder (2-1) 100 weight portions among the embodiment 2-1 is changed to 0.5 weight portion from 0.3 weight portion, all obtain particulate water-absorbing agent (2-3) according to the mode identical with embodiment 2-1.The physical property of the particulate water-absorbing agent that is obtained (2-3) is documented in the table 6.
[embodiment 2-4]
Except the addition with respect to the silica of surface-crosslinked water-absorbing resins powder (2-1) 100 weight portions among the embodiment 2-1 is changed to 0.05 weight portion from 0.3 weight portion, all obtain particulate water-absorbing agent (2-4) according to the mode identical with embodiment 2-1.The physical property of the particulate water-absorbing agent that is obtained (2-4) is documented in the table 6.
[embodiment 2-5]
Except the addition with respect to 45 weight % diethylenetriamine pentaacetic acid sodium water solutions of surface-crosslinked water-absorbing resins powder (2-1) 100 weight portions among the embodiment 2-1 is changed to 0.022 weight portion from 0.44 weight portion, all obtain particulate water-absorbing agent (2-5) according to the mode identical with embodiment 2-1.The physical property of the particulate water-absorbing agent that is obtained (2-5) is documented in the table 6.
[embodiment 2-6]
Except the addition with respect to 45 weight % diethylenetriamine pentaacetic acid sodium water solutions of surface-crosslinked water-absorbing resins powder (2-1) 100 weight portions among the embodiment 2-1 is changed to 2.2 weight portions from 0.44 weight portion, all obtain particulate water-absorbing agent (2-6) according to the mode identical with embodiment 2-1.The physical property of the particulate water-absorbing agent that is obtained (2-6) is documented in the table 6.
[embodiment 2-7]
Preparation comprises the monomer solution (2-2) of following composition: the content of p methoxy phenol is adjusted to acrylic acid 36.8 weight portions, 48 weight % sodium hydrate aqueous solutions, 12.2 weight portions, polyethyleneglycol diacrylate of 70ppm, and (average ethylene oxide unit number: n=9) 0.08 weight portion, 1 weight % diethylenetriamine pentaacetic acid trisodium (are called for short: DTPA3Na) aqueous solution 0.42 weight portion, and deionized water 30.3 weight portions.
Then, with the said monomer solution (2-2) that is adjusted into 40 ℃, use constant displacement pump to be supplied to polymerization procedure continuously.Before importing belt polymerization machine, 48 weight % sodium hydrate aqueous solutions, 18.5 weight portions are mixed continuously through the streamline mixing.At this moment, monomer temperature rises to 86 ℃ because of the heat of neutralization.Then, mix through streamline 4 weight % sodium persulfate aqueous solutions, 1.66 weight portions are mixed continuously, and the mode that the continuous mixture (2-2) that is obtained is about 7.5mm with thickness is supplied to two ends has on the planar band of rib.Carry out polymerization in 3 minutes continuously, obtain aqueous gel shape cross-linked polymer (2-2).
Then, said aqueous gel shape cross-linked polymer (2-2) is about 1.5mm with the meat grinder sectionalization of aperture 22mm.This gel through sectionalization is spread out on the mobile porous plate that is placed on the continuous ventilating band drier, obtained dry polymer (2-2) down in dry 30 minutes at 185 ℃.After the dry polymer that is obtained (2-2) pulverized with roller mill; With mesh is that the sieve of 850 μ m and 150 μ m carries out classification (removing the screenings of sieve of oversize and 150 μ m of the sieve of 850 μ m), obtains the water-absorbent besin particles (2-2) of moisture content 3 weight %, weight average particle diameter 370 μ m.Not containing its particle diameter in the water-absorbent besin particles that is obtained (2-2) in fact is the above particles of 850 μ m, and contains the fine powder less than 150 μ m of 2 weight %.
With respect to the water-absorbent besin particles that is obtained (2-2) 100 weight portions; Mix equably and comprise 1; 4-butanediol 0.3 weight portion, propane diols 0.5 weight portion, and the surface crosslinking agent of the mixed liquor of deionized water 3.0 weight portions; Thereafter with mixture 208 ℃ of following heat treated 40 minutes, obtain surface-crosslinked water-absorbing resins powder (2-2) thus.
With surface-crosslinked water-absorbing resins powder (2-2) cooling that is obtained; Thereafter with respect to surface-crosslinked water-absorbing resins powder (2-2) 100 weight portions; Interpolation also mixes 30 weight % aqueous solution of sodium bisulfite 1.66 weight portions and 45 weight % diethylenetriamine pentaacetic acid sodium water solutions, 0.44 weight portion, obtains particulate water-absorbing agent presoma (2-2).Then, the particulate water-absorbing agent presoma (2-2) that is obtained was placed 30 minutes in 60 ℃ air drier, making it thereafter is the JIS standard screen of 810 μ m through mesh.And then, with respect to surface-crosslinked water-absorbing resins powder (2-2) 100 weight portions, add and mixed silica (trade name: Aerosil200CF-5, Japanese Aerosil limited company make) 0.3 weight portion, obtain particulate water-absorbing agent (2-7) thus.The physical property of the particulate water-absorbing agent that is obtained (2-7) is documented in the table 6.
[embodiment 2-8]
Except the addition with respect to 30 weight % aqueous solution of sodium bisulfite of surface-crosslinked water-absorbing resins powder (2-1) 100 weight portions among the embodiment 2-1 is changed to 0.22 weight portion from 1.66 weight portions, all obtain particulate water-absorbing agent (2-8) according to the mode identical with embodiment 2-1.The physical property of the particulate water-absorbing agent that is obtained (2-8) is documented in the table 6.
[embodiment 2-9]
Except the addition with respect to 30 weight % aqueous solution of sodium bisulfite of surface-crosslinked water-absorbing resins powder (2-1) 100 weight portions among the embodiment 2-1 is changed to 22 weight portions from 1.66 weight portions, all obtain particulate water-absorbing agent (2-9) according to the mode identical with embodiment 2-1.The physical property of the particulate water-absorbing agent that is obtained (2-9) is documented in the table 6.
[embodiment 2-10]
Except with respect to surface-crosslinked water-absorbing resins powder (2-1) 100 weight portions among the embodiment 2-1 and then interpolation water 3 weight portions, all obtain particulate water-absorbing agent (2-10) according to the mode identical with embodiment 2-1.The physical property of the particulate water-absorbing agent that is obtained (2-10) is documented in the table 6.
[embodiment 2-11]
Except further adding 50 weight % aluminum sulfate aqueous solutions, 1.8 weight portions, 60% sodium lactate aqueous solution, 0.55 weight portion, reach the mixed solution of propane diols 0.05 weight portion, all obtain particulate water-absorbing agent (2-11) according to the mode identical with embodiment 2-1 with respect to surface-crosslinked water-absorbing resins powder (2-1) 100 weight portions among the embodiment 2-1.The physical property of the particulate water-absorbing agent that is obtained (2-11) is documented in the table 6.
[embodiment 2-12]
(average ethylene glycol unit number: addition 9) changes to 0.023 mole of % from 0.035 mole of % (with respect to monomer) with polyethyleneglycol diacrylate among the embodiment 2-1; So that becoming the mode of 350 μ m, the weight average particle diameter of water-absorbent besin particles (2-1) carries out classification; And further the heat treated condition in the surface-crosslinked step was changed to 200 ℃, 35 minutes from 208 ℃, 40 minutes; In addition, all obtain particulate water-absorbing agent (2-12) according to the mode identical with embodiment 2-1.The physical property of the particulate water-absorbing agent that is obtained (2-12) is documented in the table 6.
[comparative example 2-1]
Except not adding 45 weight % diethylenetriamine pentaacetic acid sodium water solutions, 0.22 weight portion, all obtain comparison particulate water-absorbing agent (2-1) according to the identical mode of method with embodiment 2-1 record.The physical property of the comparison particulate water-absorbing agent (2-1) that is obtained is documented in the table 6.
[comparative example 2-2]
Except not adding 30 weight % aqueous solution of sodium bisulfite, 1.66 weight portions; And the addition of silica is changed to beyond 0.5 weight portion from 0.3 weight portion, all obtain comparison particulate water-absorbing agent (2-2) according to the identical mode of method with embodiment 2-1 record.The physical property of the comparison particulate water-absorbing agent (2-2) that is obtained is documented in the table 6.
[comparative example 2-3]
0.5 weight portion, all obtain comparison particulate water-absorbing agent (2-3) except not adding silica (trade name: Aerosil 200CF-5, Japanese Aerosil limited company make) according to the mode identical with comparative example 2-2.The physical property of the comparison particulate water-absorbing agent (2-3) that is obtained is documented in the table 6.
[embodiment 2-13]
In embodiment 2-1,, likewise carry out 0.3 weight portion except not adding silica (trade name: Aerosil 200CF-5, Japanese Aerosil limited company make) with embodiment 2-1, obtain particulate water-absorbing agent (2-13).The physical property of the particulate water-absorbing agent that is obtained (2-13) is documented in the table 6.
AAP is improved as 31 [g/g] (embodiment 2-13) from 28 [g/g] (embodiment 2-1); But Vortex (absorption speed) drops to 64 seconds (embodiment 2-13) from 50 seconds (embodiment 2-1) on the contrary, and urine patience (the deterioration composition is 1000 times of amounts) becomes " mobile (embodiment 2-13) arranged ".It is thus clear that the inorganic microparticle of water-insoluble that does not disclose in patent documentation 17 grades is for urine patience and absorption speed (Vortex) outbalance.
[embodiment 2-14]
In embodiment 2-1, except not adding the p methoxy phenol in the acrylic acid when the polymerization, likewise carry out with embodiment 2-1, obtain particulate water-absorbing agent (2-14).The physical property of the particulate water-absorbing agent that is obtained (2-14) is documented in the table 6.Deterioration rate 176% with respect to embodiment 2-1 (p methoxy phenol is 70ppm in the acrylic acid); Embodiment 2-1 (is 0ppm in the acrylic acid; In the water absorbing agent for 0ppm) in the deterioration rate be 27.3%; With table 2 likewise, if p methoxy phenol is less than the requirement described in the unabridged version specification, weatherability just descends.In addition, this result is shown in Table 7.It is thus clear that the p methoxy phenol of the trace that does not disclose in patent documentation 17 grades is for the weatherability outbalance.
[table 6]
[table 7]
Figure BDA0000148091730000811
(summary)
Embodiment 2-1～2-14 and table 6～7 relate to the manufacturing approach 2 of particulate water-absorbing agent of the present invention; It is a kind of manufacturing approach (the 2nd manufacturing approach) of particulate water-absorbing agent; This manufacturing approach be comprise the steps with the manufacturing approach of polyacrylic acid (salt) water-absorbent resin as the particulate water-absorbing agent of principal component: with acrylic acid (salt) is drying steps, and the surface-crosslinked step of the polymerization procedure of the monomer solution of principal component, aqueous gel shape cross-linked polymer that polymerization gets, it is characterized in that: also comprise the interpolation step of 0.001～0.5 weight % chelating agent and the interpolation step of inorganic reducing agent; When converting with respect to acrylic acid, monomer contains the methoxybenzene phenols of 10～200ppm; The interpolation step that also comprises the inorganic microparticle of water-insoluble of (a).
Shown in said embodiment 2-1～2-12, water absorbing agent of the present invention prevent through the time coloring, urine patience, infiltration rate excellent.Only add among any the comparative example 2-1～2-3 in chelating agent or the inorganic reducing agent through the time tone relatively poor.It is relatively poor only to add among any comparative example 2-1 and the 2-3 in inorganic microparticle of water-insoluble and the chelating agent urine patience.In addition, it is also slower not contain among the comparative example 2-3 of the inorganic microparticle of water-insoluble (silica) infiltration rate.About moisture content; Amount of dust was 6mg when the moisture content of embodiment 2-10 was 4.1 weight %; Amount of dust 21mg when being 2.0 weight % with the moisture content of embodiment 2-1; The moisture content of comparative example 2-3 is that 1.7% o'clock amount of dust 40mg compares, moisture content be 3.0 weight % when above amount of dust significantly reduce.
In the preceding text; Of the present invention novel water absorbing agent shown in the said embodiment (the 2nd water absorbing agent) is with the particulate water-absorbing agent of polyacrylic acid (salt) water-absorbent resin as principal component; It contains chelating agent and inorganic reducing agent; The content of this chelating agent is 0.001～0.5 weight %, and contains the inorganic microparticle of water-insoluble.It is more than 25 [g/g] that the of the present invention novel water absorbing agent of said embodiment does not preferably have absorbent rate under pressure (CRC), adds that to depress water absorbent rate (AAP2.0kPa) be more than 25 [g/g], and Vortex (absorption speed) is below 60 seconds.Whether contain methoxybenzene phenols (especially p methoxy phenol) in this water absorbing agent for any; But likewise be made as the scope (being about about 10ppm among the said embodiment) of 5～60ppm with said (1) and novel water absorbing agent of the present invention (the 1st water absorbing agent), further improve weatherability and painted.Novel water absorbing agent of the present invention (the 2nd water absorbing agent) can likewise make moisture content less than 3 weight % with the 1st water absorbing agent, but preferred satisfy (3) and be the scope of 3～15 weight %.These water absorbing agents do not have the initial stage and through the time painted; Be white, absorption speed (Vortex) is very fast, and absorbent rate under pressure (AAP) is also higher; Even if therefore be used for the less high concentration paper nappy of paper pulp; Also have high liquid diffusivity and ooze (Re-wet) property, and do not have the coloring problem that causes by water absorbing agent, thereby good paper nappy can be provided with low contrary.
[making routine 3-1]
The commercially available acrylic acid that will be obtained with the gas phase catalytic oxidation is (superfine with the pure medicine of light, reagent; Contain p methoxy phenol 200ppm) be supplied at the bottom of the tower of high-boiling-point impurity knockout tower with 50 sections no rib porous plates; Reflux ratio is made as 1 distills; Further carry out redistillation, obtain to comprise acrylic acid reaches trace impurity (being mainly water) more than 99% purifying propenoic acid (3-1) thus.P methoxy phenol amount in the purifying propenoic acid (3-1) is ND (less than 1ppm).ND is meant proportional less than 1ppm with respect to containing of purifying propenoic acid (3-1).
Through interpolation 70ppm p methoxy phenol in purifying propenoic acid (3-1), and obtained adjustment acrylic acid (3-1).
[comparative example 3-1]
In the reactor that forms in cover lid on the two wrist formula kneaders of the stainless die of band sleeve pipe of the volume 10L with 2 Sigma's type blades, make the following substances dissolving and process reactant liquor: make adjustment acrylic acid (3-1) 408.4g that obtained among the routine 3-1, through will make the adjustment acrylic acid (3-1) that obtained among the routine 3-1 with pure water dilution and the 37 weight % PAA aqueous solution 4321.9g that obtain with sodium hydrate aqueous solution (ferrous components content 0.7ppm (with respect to the NaOH solid constituent)) neutralization, pure water 724.2g, reach polyethyleneglycol diacrylate (molecular weight 523) 4.74g.
Then, this reactant liquor was outgased 30 minutes under nitrogen environment.Then, one side stirs 10 weight % sodium persulfate aqueous solution 29.5g and 0.1 weight %L-aqueous ascorbic acid 11.3g simultaneously is added in the reactant liquor, and the result begins polymerization after about 25 seconds.Then, the gel that generates is pulverized, and carried out polymerization more than 25 ℃, below 95 ℃, after polymerization begins 30 minutes, take out aqueous gel shape cross-linked polymer (C1-a).The aqueous gel shape cross-linked polymer segmentation that is obtained is turned to diameter to be about below the 5mm.In addition, the solid constituent amount of aqueous gel shape cross-linked polymer (C1-a) (loss on drying according under 180 ℃, 3 hours is calculated) is 37.5 weight %.
Aqueous gel shape cross-linked polymer (C1-a) is spread out on the wire netting in 50 holes; Under 170 ℃, carry out 65 minutes heated-air dryings; Re-using roller mill pulverizes dry thing; Be that the JIS standard screen of 850 μ m carries out classification and allocates further, obtain the logstandard deviation that weight average particle diameter (D50) is 371 μ m, size distribution (σ ζ) thus and be 0.34 unsetting broken shape water-absorbent besin particles (C1-c) with mesh.It is 46 (g/g) that the centrifugal separator of water-absorbent besin particles (C1-c) keeps capacity (CRC), and the water soluble composition is 18 weight %.
In the water-absorbent besin particles that is obtained (C1-c) 100 weight portions; Mix equably and comprise ethylene glycol diglycidylether 0.027 weight portion, 1; 4-butanediol 0.3 weight portion, 1; 2-propane diols 0.5 weight portion, and the surface crosslinking agent of the mixed liquor of pure water 2.8 weight portions, thereafter with mixture 180 ℃ of following heat treated 60 minutes.The particle crushing that obtained to through mesh be the JIS standard screen of 850 μ ms, obtained surface crosslinked comparison particulate water-absorbing agent (3-1) take place thereafter.The analysis result that will compare particulate water-absorbing agent (3-1) is documented in table 8 and the table 9.
[embodiment 3-11
Through likewise carrying out polymerization, obtain aqueous gel shape cross-linked polymer (1-a) with comparative example 3-1.Add 0.375 weight % aqueous solution of sodium bisulfite with the charging rate of 30 [g/min]; And with the charging rate of 600 [g/min] with the aqueous gel shaped polymer (1-a) that is obtained with meat grinder (meat grinder model: 12VR-400KSOX, meal tomb Industries, Inc, mould aperture: 11mm, hole count: 10, mold thickness: 8mm) pulverize again; Make aqueous solution of sodium bisulfite mix (in reducing agent 500ppm) equably in aqueous gel shape cross-linked polymer (1-a), obtain aqueous gel shape cross-linked polymer (1-b) thus through sectionalization.
This aqueous gel shape cross-linked polymer (1-b) through sectionalization is spread out on the wire netting in 50 holes; 170 ℃ of following heated-air dryings 65 minutes; Re-using roller mill pulverizes dry thing; Further utilizing mesh is that the JIS standard screen of 850 μ m carries out classification and allocates, and obtains the logstandard deviation that weight average particle diameter (D50) is 371 μ m, size distribution (σ ζ) thus and be 034 unsetting broken shape water-absorbent besin particles (1-c).It is 46 (g/g) that the centrifugal separator of water-absorbent besin particles (1-c) keeps capacity (CRC), and the water soluble composition is 18 weight %.
In the water-absorbent besin particles that is obtained (1-c) 100 weight portions; Mix equably and comprise ethylene glycol diglycidylether 0.020 weight portion, 1; The surface crosslinking agent of the mixed liquor of 2-propane diols 1.5 weight portions, pure water 3.5 weight portions; Mixture equably spread on stainless steel groove, and groove integral body is airtight, 100 ℃ of following heat treated 40 minutes with the sack of polyethylene system thereafter.The particle crushing that obtained to through mesh be the JIS standard screen of 850 μ ms, obtained surface crosslinked water-absorbent besin particles (1-d) take place thereafter.
In the water-absorbent besin particles that is obtained (1-d) 100 weight portions, add and mix 0.5 weight % ethylenediamine tetraacetic (methylene phosphonic acid), five sodium (be called for short: the EDTMPA5Na) aqueous solution 1.0 weight portions obtain particulate water-absorbing agent (3-1).The analysis result of particulate water-absorbing agent (3-1) is documented in table 8 and the table 9.
[embodiment 3-2]
Except the charging rate with 0.375 weight % aqueous solution of sodium bisulfite changes to 12 [g/min] from 30 [g/min], all obtain particulate water-absorbing agent (3-2) according to the mode identical with embodiment 3-1.The analysis result of particulate water-absorbing agent (3-2) is documented in table 8 and the table 9.
[embodiment 3-3]
Except (be called for short: EDTMPA5Na) aqueous solution changes to 2.5 weight % ethylenediamine tetraacetics (methylene phosphonic acid), five sodium (abbreviation: the EDTMPA5Na) aqueous solution with 0.5 weight % ethylenediamine tetraacetic (methylene phosphonic acid), five sodium; And to be made as its addition with respect to water-absorbent besin particles 100 weight portions be beyond 2.0 weight portions; All, obtain water-absorbent besin particles (3-e) according to the mode identical with embodiment 3-1.Through in the water-absorbent besin particles that is obtained (3-e) 100 weight portions, adding and mixed silica gel (trade name: Aerosil200, Japanese Aerosil manufactured) 0.3 weight portion, obtain particulate water-absorbing agent (3-3).The analysis result of particulate water-absorbing agent (3-3) is documented in table 8 and the table 9.
[embodiment 3-4]
Except (be called for short: EDTMPA5Na) aqueous solution changes to 2.5 weight % ethylenediamine tetraacetics (methylene phosphonic acid), five sodium (abbreviation: the EDTMPA5Na) aqueous solution with 0.5 weight % ethylenediamine tetraacetic (methylene phosphonic acid), five sodium; And be made as its addition with respect to water-absorbent besin particles 100 weight portions to be beyond 4.0 weight portions, all to obtain particulate water-absorbing agent (3-4) according to the mode identical with embodiment 3-1.The analysis result of particulate water-absorbing agent (3-4) is documented in table 8 and the table 9.
[embodiment 3-5]
The concentration of 0.375 weight % aqueous solution of sodium bisulfite is changed to 0.1 weight %; Its charging rate is changed to 22.5 [g/min] from 30 [g/min]; (be called for short: EDTMPA5Na) aqueous solution changes to 2.5 weight portion ethylenediamine tetraacetics (methylene phosphonic acid), five sodium (abbreviation: the EDTMPA5Na) aqueous solution with 0.5 weight % ethylenediamine tetraacetic (methylene phosphonic acid), five sodium; And to be made as its addition with respect to water-absorbent besin particles 100 weight portions be 2.0 weight portions; In addition, all obtain particulate water-absorbing agent (3-5) according to the mode identical with embodiment 3-1.The analysis result of particulate water-absorbing agent (3-5) is documented in table 8 and the table 9.
[embodiment 3-6]
Except the charging rate with 0.375 weight % aqueous solution of sodium bisulfite changes to 60 [g/min] from 30 [g/min]; (be called for short: EDTMPA5Na) addition of the aqueous solution changes to respect to water-absorbent besin particles 100 weight portions to be beyond 4.0 weight portions, all to obtain particulate water-absorbing agent (3-6) according to the mode identical with embodiment 3-1 with 0.5 weight % ethylenediamine tetraacetic (methylene phosphonic acid), five sodium.The analysis result of particulate water-absorbing agent (3-6) is documented in table 8 and the table 9.
[embodiment 3-7]
Except the concentration with 0.375 weight % aqueous solution of sodium bisulfite changes to 3.75 weight %, and its charging rate is changed to 30 [g/min] in addition from 60 [g/min], all obtain particulate water-absorbing agent (3-7) according to the mode identical with embodiment 3-6.The analysis result of particulate water-absorbing agent (3-7) is documented in table 8 and the table 9.
[embodiment 3-8]
Except the charging rate with 3.75 weight % aqueous solution of sodium bisulfite changes to 60 [g/min] from 30 [g/min], all obtain particulate water-absorbing agent (3-8) according to the mode identical with embodiment 3-7.The analysis result of particulate water-absorbing agent (3-8) is documented in table 8 and the table 9.
[embodiment 3-9]
The p methoxy phenol of making routine 3-1 record is changed to 10ppm with respect to the addition of purifying propenoic acid from 70ppm, obtained adjustment acrylic acid (3-2) thus.
Except using adjustment acrylic acid (3-2), all obtain the surface crosslinked water-absorbent besin particles (9-d) takes place according to the mode identical with embodiment 3-1.
In the water-absorbent besin particles that is obtained (9-d) 100 weight portions, add and mix 0.5 weight % ethylenediamine tetraacetic (methylene phosphonic acid), five sodium (be called for short: the EDTMPA5Na) aqueous solution 4.0 weight portions have obtained water-absorbent besin particles (9-e) thus.
Through in the water-absorbent besin particles that is obtained (9-e) 100 weight portions, adding and mixed silica gel (trade name: Aerosil 200, Japanese Aerosil manufactured) 0.3 weight portion, obtained particulate water-absorbing agent (3-9).The analysis result of particulate water-absorbing agent (3-9) is documented in table 8 and the table 9.In addition, the weatherability of particulate water-absorbing agent (3-9) promotes that the deterioration rate of test is 12%.
[embodiment 3-10]
The p methoxy phenol of making routine 3-1 record is changed to 200ppm with respect to the addition of purifying propenoic acid from 70ppm, obtained adjustment acrylic acid (3-3) thus.
Except using adjustment acrylic acid (3-3), all obtain the surface crosslinked water-absorbent besin particles (10-d) takes place according to the mode identical with embodiment 3-1.
In the water-absorbent besin particles that is obtained (10-d) 100 weight portions, add and mix 1 weight % ethylenediamine tetraacetic (methylene phosphonic acid), five sodium (be called for short: the EDTMPA5Na) aqueous solution 2.0 weight portions have obtained water-absorbent besin particles (10-e) thus.
Through interpolation and mixed silica gel (trade name: Aerosil 200, Japanese Aerosil manufactured) 0.3 weight portion in the water-absorbent besin particles that is obtained (10-e) 100 weight portions, and obtained particulate water-absorbing agent (3-10).The analysis result of particulate water-absorbing agent (3-10) is documented in table 8 and the table 9.
[embodiment 3-11]
The concentration of 0.375 weight % aqueous solution of sodium bisulfite is changed to 1 weight %; And its charging rate changed to 45 [g/min] from 30 [g/min]; (be called for short: EDTMPA5Na) to be made as with respect to water-absorbent besin particles 100 weight portions be 5.0 weight portions to the addition of the aqueous solution with 1 weight % ethylenediamine tetraacetic (methylene phosphonic acid), five sodium; And then add 15 weight % sodium lactate aqueous solutions, 2 weight portions with respect to water-absorbent besin particles 100 weight portions; In addition, all obtain particulate water-absorbing agent (3-11) according to the mode identical with embodiment 3-1.The analysis result of particulate water-absorbing agent (3-11) is documented in table 8 and the table 9.
[embodiment 3-12]
The concentration of 0.375 weight % aqueous solution of sodium bisulfite is changed to 1 weight %; And its charging rate changed to 45 [g/min] from 30 [g/min]; (be called for short: EDTMPA5Na) to be made as with respect to water-absorbent besin particles 100 weight portions be 5.0 weight portions to the addition of the aqueous solution with 1 weight % ethylenediamine tetraacetic (methylene phosphonic acid), five sodium; And then add 25 weight % aluminum sulfate aqueous solution 2 weight portions and 15 weight % sodium lactate aqueous solutions, 2 weight portions with respect to water-absorbent besin particles 100 weight portions; In addition, all obtain particulate water-absorbing agent (3-12) according to the mode identical with embodiment 3-1.The analysis result of particulate water-absorbing agent (3-12) is documented in table 8 and the table 9.
[embodiment 3-13]
Through in water-absorbent besin particles (3-11) 100 weight portions of embodiment 3-11 record, adding and mixed silica (trade name: Aerosil 200, Japanese Aerosil manufactured) 0.5 weight portion, obtain particulate water-absorbing agent (3-13).The analysis result of particulate water-absorbing agent (3-13) is documented in table 8 and the table 9.
[comparative example 3-2]
Through likewise carrying out polymerization, obtain aqueous gel shape cross-linked polymer (C2-a) with comparative example 3-1.Add 0.1% aqueous solution of sodium bisulfite with the charging rate of 18 [g/min]; And the charging rate with 600 [g/min] is utilized meat grinder (meat grinder model: 12VR-400KSOX, meal tomb Industries, Inc, mould aperture: 11mm, hole count: 10, mold thickness: 8mm) pulverize again with the aqueous gel shaped polymer (C2-a) that is obtained; And aqueous solution of sodium bisulfite is blended in the aqueous gel shape cross-linked polymer (C2-a) equably, obtain aqueous gel shape cross-linked polymer (C2-b) thus through sectionalization.
This aqueous gel shape cross-linked polymer (C2-b) through sectionalization is spread out on the wire netting in 50 holes; Under 170 ℃, carry out 65 minutes heated-air dryings; Re-using roller mill pulverizes dry thing; And with mesh is that the JIS standard screen of 850 μ m carries out classification and allocates, and obtains the logstandard deviation that weight average particle diameter (D50) is 371 μ m, size distribution (σ ζ) thus and be 0.34 unsetting broken shape water-absorbent besin particles (1-c).It is 46 (g/g) that the centrifugal separator of water-absorbent besin particles (C2-c) keeps capacity (CRC), and the water soluble composition is 18 weight %.
In the water-absorbent besin particles that is obtained (C2-c) 100 weight portions; Mix equably and comprise ethylene glycol diglycidylether 0.027 weight portion, 1; 4-butanediol 0.3 weight portion, 1; The surface crosslinking agent of the mixed liquor of 2-propane diols 0.5 weight portion, pure water 2.8 weight portions, thereafter with mixture 180 ℃ of following heat treated 60 minutes.The particle crushing that obtained to through mesh be the JIS standard screen of 850 μ ms, obtained surface crosslinked comparison particulate water-absorbing agent (3-2) take place thereafter.The analysis result that will compare particulate water-absorbing agent (3-2) is documented in table 8 and the table 9.
[comparative example 3-3]
Through in water-absorbent besin particles (3-1) 100 weight portions relatively, adding and mixing 0.05 weight % ethylenediamine tetraacetic (methylene phosphonic acid), five sodium (be called for short: the EDTMPA5Na) aqueous solution 1.0 weight portions have obtained relatively particulate water-absorbing agent (3-3).The analysis result that will compare particulate water-absorbing agent (3-3) is documented in table 8 and the table 9.
[comparative example 3-4]
Except the concentration with 0.375 weight % aqueous solution of sodium bisulfite changes to 30 weight %; And charging rate changed to 26.25 [g/min] in addition from 60 [g/min], all according to obtaining comparison aqueous gel shape cross-linked polymer (C4-b) through sectionalization with embodiment 3-1 identical operations.
To spread out on the wire netting in 50 holes through the comparison aqueous gel shape cross-linked polymer (C4-b) of sectionalization; Under 170 ℃, carry out 65 minutes heated-air dryings; Re-using roller mill pulverizes dry thing; Be that the JIS standard screen of 850 μ m carries out classification and allocates further, obtain the logstandard deviation that weight average particle diameter (D50) is 371 μ m, size distribution (σ ζ) thus and be relatively water-absorbent besin particles (C4-c) of 0.34 unsetting broken shape with mesh.Relatively the centrifugal separator of water-absorbent besin particles (C4-c) maintenance capacity (CRC) is 44 [g/g], and the water soluble composition is 16 weight %.
In comparison water-absorbent besin particles (C4-c) 100 weight portions that obtained; Mix equably and comprise ethylene glycol diglycidylether 0.027 weight portion, 1; 4-butanediol 0.3 weight portion, 1; 2-propane diols 0.5 weight portion, and the surface crosslinking agent of the mixed liquor of pure water 2.8 weight portions, thereafter with mixture 180 ℃ of following heat treated 60 minutes.The particle crushing that obtained to through mesh be the JIS standard screen of 850 μ ms, obtained surface crosslinked comparison particulate water-absorbing agent (3-4) take place thereafter.The analysis result that will compare particulate water-absorbing agent (3-4) is documented in table 8 and the table 9.
[comparative example 3-5]
The concentration of aqueous solution of sodium bisulfite is changed to 30 weight % from 0.375 weight %; And its charging rate changed to 45 [g/min] from 60 [g/min]; And not adding ethylenediamine tetraacetic (methylene phosphonic acid) five sodium (is called for short: the EDTMPA5Na) aqueous solution; In addition, all obtain comparison particulate water-absorbing agent (3-5) according to the mode identical with embodiment 3-1.
[comparative example 3-6]
In making routine 3-1, p methoxy phenol is changed to 1ppm with respect to the addition of purifying propenoic acid from 70ppm, obtained adjustment acrylic acid (3-6) thus.Except using adjustment acrylic acid (3-6),, obtained comparison aqueous gel shape cross-linked polymer (C6-b) through sectionalization all according to the mode identical with the record of embodiment 3-1.
This comparison aqueous gel shape cross-linked polymer (C6-b) through sectionalization is spread out on the wire netting in 50 holes; Under 170 ℃, carry out 65 minutes heated-air dryings; Re-using roller mill pulverizes dry thing; Be that the JIS standard screen of 850 μ m carries out classification and allocates further, obtain the logstandard deviation that weight average particle diameter (D50) is 371 μ m, size distribution (σ ζ) thus and be relatively water-absorbent besin particles (C6-c) of 0.34 unsetting broken shape with mesh.Relatively the centrifugal separator of water-absorbent besin particles (C6-c) maintenance capacity (CRC) is 50 [g/g], and the water soluble composition is 24 weight %.
In comparison water-absorbent besin particles (C6-c) 100 weight portions that obtained; Mix equably and comprise ethylene glycol diglycidylether 0.027 weight portion, 1; 4-butanediol 0.3 weight portion, 1; 2-propane diols 0.5 weight portion, and the surface crosslinking agent of the mixed liquor of pure water 2.8 weight portions, thereafter with mixture 180 ℃ of following heat treated 60 minutes.The particle crushing that obtained to through mesh be the JIS standard screen of 850 μ ms, obtained surface crosslinked comparison water-absorbent besin particles (C6-d) take place thereafter.
In comparison water-absorbent besin particles (C6-d) 100 weight portions that obtained, add and mix 5 weight % ethylenediamine tetraacetics (methylene phosphonic acid), five sodium (be called for short: the EDTMPA5Na) aqueous solution 0.4 weight portion obtains relatively water-absorbent besin particles (C6-e).
Through in comparison water-absorbent besin particles (6-e) 100 weight portions that obtained, adding and mixed silica gel (trade name: Aerosil 200, Japanese Aerosil manufactured) 0.3 weight portion, obtain relatively particulate water-absorbing agent (3-6).
Relatively the weatherability of particulate water-absorbing agent (3-6) promotes that the deterioration rate of test is 24%, is the relatively poor particulate water-absorbing agent of weatherability.
[comparative example 3-7]
In making routine 3-1, p methoxy phenol is changed to 270ppm with respect to the addition of purifying propenoic acid from 70ppm, obtained adjustment acrylic acid (3-7) thus.Except using adjustment acrylic acid (3-7), all obtained relatively particulate water-absorbing agent (3-7) according to the mode identical with comparative example 3-6.
[comparative example 3-8]
Below, disclose moisture content and painted relation.Promptly; Except the concentration with 0.375 weight % aqueous solution of sodium bisulfite changes to 0.1 weight %; And further its charging rate is changed to 22.5 [g/min] in addition from 30 [g/min]; All carry out identical operations, and obtained the crosslinked water-absorbent besin particles of surperficial generation (C8-d) with embodiment 3-1.
In the water-absorbent besin particles that is obtained (C8-d) 100 weight portions; Interpolation also mixes 0.5 weight % ethylenediamine tetraacetic (methylene phosphonic acid), five sodium and (is called for short: the EDTMPA5Na) aqueous solution 1.0 weight portions; And further add and mix deionized water 13 weight portions, obtain relatively particulate water-absorbing agent (3-8) of moisture content 17 weight % thus.The analysis result that will compare particulate water-absorbing agent (3-8) is documented in table 8 and the table 9.In addition, moisture content 17 weight % relatively particulate water-absorbing agent (3-8) compare with the water absorbing agent of moisture content of the present invention shown in table, and painted relatively poor, particle condenses caking easily, and operability is relatively poor.
[table 8]
[table 9]
Figure BDA0000148091730000911
(summary)
More than; Said embodiment 3-1～embodiment 3-13 and table 8, table 9 relate to the manufacturing approach 3 of particulate water-absorbing agent of the present invention, its be comprise the steps with the manufacturing approach of polyacrylic acid (salt) water-absorbent resin as the particulate water-absorbing agent of principal component: with acrylic acid (salt) is drying steps, and the surface-crosslinked step of the polymerization procedure of the monomer solution of principal component, aqueous gel shape cross-linked polymer that polymerization gets; And comprise the interpolation step of 0.001～0.5 weight % chelating agent and the interpolation step of inorganic reducing agent; When converting with respect to acrylic acid, monomer contains the methoxybenzene phenols of 10～200ppm; Behind drying steps, and surface-crosslinked step in, the moisture content of polymer is controlled at 3～15 weight %; And then preferably the aqueous gel shape cross-linked polymer before dry adds said inorganic reducing agent.
Shown in said embodiment 3-1～3-13, contain chelating agent and inorganic reducing agent in the particulate water-absorbing agent of the present invention, and moisture content is 3～15 weight %, rely on this formation, through the time tone and initial stage tone excellent, and do not have undesirable foul smell.Only contain among any the comparative example 3-1～3-3 in chelating agent or the inorganic reducing agent, through the time tone relatively poor.In addition, only in reducing agent and its addition more comparative example 3-4 and 3-5, the foul smell of particulate water-absorbing agent is very strong.Metoxyphenol amount in the acrylic acid is that the metoxyphenol amount in 10～200ppm or the water absorbing agent is that the deterioration rate of particulate water-absorbing agent is higher, and weatherability is relatively poor among the extraneous comparative example 3-6 of 5～60ppm (in acrylic acid, being 1ppm).In addition, initial coloration is relatively poor among the comparative example 3-7 (being 270ppm in acrylic acid), and produces foul smell.This foul smell is the foul smell of reducing agent itself, not equal to be foul smell from surface-crosslinked secondary product.In addition, about moisture content, comparative example 3-8 (moisture content 17 weight %) compares with water absorbing agent of the present invention, and is painted relatively poor, and in addition, urine patience (1000 times of deterioration compositions) is also relatively poor.In addition, manufacturing approach of the present invention has solved deterioration, foul smell and painted problem, and remaining monomer is lower, below 400ppm, and then is below the 300ppm.
In the preceding text; Of the present invention novel water absorbing agent shown in the said embodiment (the 3rd water absorbing agent) is to be the particulate water-absorbing agent of principal component with polyacrylic acid (salt) water-absorbent resin; Contain chelating agent and inorganic reducing agent; The content of this chelating agent is 0.001～0.5 weight %, and moisture content is 3～15 weight %.It is more than 25 [g/g] that of the present invention novel water absorbing agent shown in the said embodiment does not preferably have absorbent rate under pressure (CRC), adds that to depress water absorbent rate (AAP2.0kPa) be more than 25 [g/g], and remaining monomer is below the 500ppm.Whether contain methoxybenzene phenols (especially p methoxy phenol) in this water absorbing agent for any; The methoxybenzene phenols that can contain 0～200ppm; But preferably likewise the content of methoxybenzene phenols is controlled at the scope (being about about 10ppm among said embodiment 3-1～3-8) of 5～60ppm, and further improves weatherability and painted with said (1) and novel water absorbing agent of the present invention (the 1st water absorbing agent).Novel water absorbing agent of the present invention (the 3rd water absorbing agent) is preferably through likewise containing the inorganic microparticle of water-insoluble with said (1) and novel water absorbing agent of the present invention (the 1st water absorbing agent), and further improves urine patience.This water absorbing agent also preferably also contains the alpha-hydroxy carboxylic acid compounds compound.In addition, also contain multivalent metal salt and/or cation property copolymer.
These water absorbing agents do not have the initial stage and through the time painted, be white, and remaining monomer is less; Absorption speed (Vortex) is very fast; Absorbent rate under pressure (AAP) is also higher, even if therefore be used in the less high concentration paper nappy of paper pulp, also has high liquid diffusivity and low contrary (Re-wet) property of oozing; And there is not the coloring problem that causes by water absorbing agent, thereby good paper nappy can be provided.
[utilizability on the industry]
Be applicable to hygienic materials such as paper nappy, sanitary napkin, incontinence protection through the particulate water-absorbing agent that manufacturing approach of the present invention obtained.

Claims (39)

1. particulate water-absorbing agent, it is characterized in that as principal component with polyacrylic acid (salt) water-absorbent resin:
Contain chelating agent and inorganic reducing agent;
The content of this chelating agent is 0.001～0.5 weight %;
More than one important document in (1)～(3) below satisfying:
(1) content of methoxybenzene phenols is 5～60ppm,
(2) contain the inorganic microparticle of water-insoluble,
(3) moisture content is 3～15 weight %.
2. particulate water-absorbing agent according to claim 1 is characterized in that:
Satisfy plural important document in said (1)～(3).
3. particulate water-absorbing agent according to claim 1 and 2 is characterized in that:
Satisfy whole important document in said (1)～(3).
4. according to each described particulate water-absorbing agent in the claim 1～3, it is characterized in that:
The content of said chelating agent is 0.001～0.1 weight %.
5. according to each described particulate water-absorbing agent in the claim 1～4, it is characterized in that:
The content of methoxybenzene phenols is 5～60ppm.
6. according to each described particulate water-absorbing agent in the claim 1～5, it is characterized in that:
Said chelating agent is the compound more than at least a kind that is selected from the group that is made up of amino polybasic carboxylic acid, organic multicomponent phosphoric acid, inorganic multivariate phosphoric acid, amino polynary phosphoric acid.
7. according to each described particulate water-absorbing agent in the claim 1～6, it is characterized in that:
The content of said inorganic reducing agent is 0.01～1.0 weight %.
8. according to each described particulate water-absorbing agent in the claim 1～7, it is characterized in that:
Said inorganic reducing agent is the water-soluble inorganic compound with reducing inorganic element.
9. according to each described particulate water-absorbing agent in the claim 1～7, it is characterized in that:
Said inorganic reducing agent is the water-soluble organic compounds with reducing inorganic element.
10. according to each described particulate water-absorbing agent in the claim 1～9, it is characterized in that:
Said inorganic reducing agent is the compound more than at least a kind that is selected from the group that is made up of sulphite, bisulfites, pyrosulfite, dithionite.
11., it is characterized in that according to each described particulate water-absorbing agent in the claim 1～10:
Contain the inorganic microparticle of water-insoluble, and the content of the inorganic microparticle of said water-insoluble is 0.05～1.0 weight %.
12. particulate water-absorbing agent according to claim 11 is characterized in that:
The inorganic microparticle of said water-insoluble is a silica.
13., it is characterized in that according to each described particulate water-absorbing agent in the claim 1～12:
Also contain the alpha-hydroxy carboxylic acid compounds compound.
14. particulate water-absorbing agent according to claim 13 is characterized in that:
Said alpha-hydroxy carboxylic acid compounds compound is the compound more than at least a kind that is selected from the group that is made up of lactic acid (salt) and malic acid (salt).
15., it is characterized in that according to each described particulate water-absorbing agent in the claim 1～14:
Also contain multivalent metal salt and/or cation property copolymer.
16., it is characterized in that according to each described particulate water-absorbing agent in the claim 1～15:
The content of iron is below the 2ppm.
17., it is characterized in that according to each described particulate water-absorbing agent in the claim 1～16:
Said polyacrylic acid (salt) water-absorbent resin is the granulation thing.
18., it is characterized in that according to each described particulate water-absorbing agent in the claim 1～17:
Arbitrary important document below also satisfying in (4)～(7):
(4) add and depress water absorbent rate AAP4.83kPa or add that to depress water absorbent rate AAP2.0kPa be more than the 20g/g,
(5) saline solution water conservancy diversion property SFC is 30 * 10 -7Cm 3Sg -1More than,
(6) absorption speed Vortex is below 60 seconds, or absorption speed FSR is more than the 0.20g/g/sec,
(7) remaining monomer is below the 500ppm.
19., it is characterized in that according to each described particulate water-absorbing agent in the claim 1～17:
No absorbent rate under pressure CRC is more than the 25g/g;
Add that to depress water absorbent rate AAP4.83kPa be more than the 20g/g;
Saline solution water conservancy diversion property SFC is 30 * 10 -7Cm 3Sg -1More than.
20., it is characterized in that according to each described particulate water-absorbing agent in the claim 1～17:
No absorbent rate under pressure CRC is more than the 25g/g;
Add that to depress water absorbent rate AAP2.0kPa be more than the 25g/g;
Absorption speed Vortex is below 60 seconds.
21. one kind is the manufacturing approach of the particulate water-absorbing agent of principal component with polyacrylic acid (salt) water-absorbent resin; It comprises that with acrylic acid (salt) be the polymerization procedure of the monomer solution of principal component, drying steps, the surface-crosslinked step of aqueous gel shape cross-linked polymer that polymerization gets
The manufacturing approach of this particulate water-absorbing agent is characterised in that:
Also comprise the interpolation step of 0.001～0.5 weight % chelating agent and the interpolation step of inorganic reducing agent;
Methoxybenzene phenols in the said monomer solution is 10～200ppm with respect to acrylic acid conversion content;
More than one important document in (a)～(c) below satisfying:
(a) also comprise the interpolation step of the inorganic microparticle of water-insoluble,
(b) behind drying steps, and in surface-crosslinked step, the moisture content of polymer is controlled at 3～15 weight %,
(c) after surface-crosslinked step, add said inorganic reducing agent.
22. manufacturing approach according to claim 21 is characterized in that:
Satisfy plural important document in said (a)～(c).
23., it is characterized in that according to claim 21 or 22 described manufacturing approaches:
Satisfy said (a) and (b).
24., it is characterized in that according to claim 21 or 22 described manufacturing approaches:
Satisfy whole important document in said (a)～(c).
25., it is characterized in that according to each described manufacturing approach in the claim 21～24:
Comprise: be the interpolation step of the drying steps of the polymerization procedure of the monomer solution of principal component, aqueous gel shape cross-linked polymer that polymerization gets, surface-crosslinked step, chelating agent with the acrylic acid (salt) of the methoxybenzene phenols that contains 10～200 ppm by weight;
After surface-crosslinked step, carry out the interpolation step of the inorganic reducing agent of said (c).
26., it is characterized in that according to each described manufacturing approach in the claim 21～25:
Methoxybenzene phenols contained in the said monomer solution is a p methoxy phenol, and is 10～120ppm with respect to acrylic acid conversion content.
27., it is characterized in that according to each described manufacturing approach in the claim 21～26:
With said chelating agent be added into before the polymerization or monomer solution in the polymerization process in.
28., it is characterized in that according to each described manufacturing approach in the claim 21～27:
Said inorganic reducing agent is added in the dry preceding aqueous gel shape cross-linked polymer.
29., it is characterized in that according to each described manufacturing approach in the claim 21～28:
Said inorganic reducing agent is the water-soluble inorganic compound with reducing inorganic element.
30., it is characterized in that according to each described manufacturing approach in the claim 21～29:
Said inorganic reducing agent is the water-soluble organic compounds with reducing inorganic element.
31., it is characterized in that according to each described manufacturing approach in the claim 21～30:
Said inorganic reducing agent is the compound with reducible sulfur atom or reproducibility phosphorus atoms.
32., it is characterized in that according to each described manufacturing approach in the claim 21～31:
The interpolation step that also comprises the alpha-hydroxy carboxylic acid compounds compound.
33., it is characterized in that according to each described manufacturing approach in the claim 21～32:
The interpolation step that also comprises multivalent metal salt and/or cation property copolymer.
34., it is characterized in that according to each described manufacturing approach in the claim 21～33:
Also comprise granulation step.
35., it is characterized in that according to each described manufacturing approach in the claim 21～34:
Said polymerization procedure is the step of carrying out aqueous solution polymerization.
36., it is characterized in that according to each described manufacturing approach in the claim 21～35:
Also comprise: the gel grain refined step that in polymerization process or after polymerization, aqueous gel shape cross-linked polymer is imposed grain refined.
37. manufacturing approach according to claim 36 is characterized in that:
When said aqueous gel shape cross-linked polymer is imposed grain refined, add inorganic reducing agent.
38., it is characterized in that according to each described manufacturing approach in the claim 21～37:
Employed surface crosslinking agent is polynary epoxide in the said surface-crosslinked step.
39., it is characterized in that according to each described manufacturing approach in the claim 21～38:
Also comprise neutralization procedure;
Said polymerization procedure is following steps: with the radical polymerization initiator of 0.001～1 mole of %; In maximum temperature is below 130 ℃ and polymerization time is under 0.5 minute～3 hours the condition; Making monomer concentration is that the monomer solution of 30～55 weight % carries out aqueous solution polymerization or inverse suspension polymerization; Wherein, the monomer in this monomer solution comprises the acrylic acid (salt) of 90～100 moles of %;
Said neutralization procedure is that to utilize Fe content be that the alkali of 0～7ppm carries out;
Said drying steps is following steps: under 100～250 ℃ of baking temperatures, with 10～120 minutes drying time, make be made into granular, polymerization and aqueous gel shape cross-linked polymer to be dried to moisture content be below the 20 weight %;
Said surface-crosslinked step is following steps: absorbent resin powder 100 weight portions after finishing with respect to drying steps, and blending surface crosslinking agent 0.001～10 weight portion, and 70～300 ℃ of following heat treated 1 minute～2 hours;
Making the methoxybenzene phenols content of the particulate water-absorbing agent of acquisition is 5～60ppm.
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