WO2009093708A1 - Water absorbent and process for production thereof - Google Patents

Water absorbent and process for production thereof Download PDF

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Publication number
WO2009093708A1
WO2009093708A1 PCT/JP2009/051115 JP2009051115W WO2009093708A1 WO 2009093708 A1 WO2009093708 A1 WO 2009093708A1 JP 2009051115 W JP2009051115 W JP 2009051115W WO 2009093708 A1 WO2009093708 A1 WO 2009093708A1
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Prior art keywords
water
absorbing agent
group
polysiloxane
mass
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PCT/JP2009/051115
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French (fr)
Japanese (ja)
Inventor
Kazushi Torii
Taishi Kobayashi
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Nippon Shokubai Co., Ltd.
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Publication of WO2009093708A1 publication Critical patent/WO2009093708A1/en

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    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L101/00—Compositions of unspecified macromolecular compounds
    • C08L101/12—Compositions of unspecified macromolecular compounds characterised by physical features, e.g. anisotropy, viscosity or electrical conductivity
    • C08L101/14—Compositions of unspecified macromolecular compounds characterised by physical features, e.g. anisotropy, viscosity or electrical conductivity the macromolecular compounds being water soluble or water swellable, e.g. aqueous gels
    • 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
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F20/00—Homopolymers and 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 a salt, anhydride, ester, amide, imide or nitrile thereof
    • C08F20/02—Monocarboxylic acids having less than ten carbon atoms, Derivatives thereof
    • 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
    • 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
    • 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

Definitions

  • the present invention relates to a water-absorbing agent containing a water-absorbing resin and a water-soluble polysiloxane having a dissociating group, and a method for producing the same.
  • water-absorbent resins have been widely used as main constituent materials in hygiene materials (absorbent articles) such as disposable diapers, sanitary napkins, incontinence pads, etc. for the purpose of absorbing body fluids (urine and blood).
  • hygiene materials such as disposable diapers, sanitary napkins, incontinence pads, etc.
  • water-absorbing resin include a crosslinked polyacrylic acid partial neutralized product, a hydrolyzate of starch-acrylonitrile graft polymer, a neutralized product of starch-acrylic acid graft polymer, and a vinyl acetate-acrylic acid ester copolymer.
  • Saponified product of polymer, crosslinked carboxymethyl cellulose, hydrolyzate of acrylonitrile copolymer or acrylamide copolymer or cross-linked product thereof, crosslinked product of cationic monomer, crosslinked isobutylene-maleic acid copolymer, 2-acrylamide-2 -A cross-linked product of methylpropanesulfonic acid and acrylic acid is known.
  • water absorption characteristics desired for these water-absorbing agents include high absorption capacity when in contact with aqueous liquids such as body fluids, especially high water absorption capacity under load, excellent absorption rate, liquid permeability, gel strength of swollen gel
  • a suction amount for sucking water from a base material containing an aqueous liquid is a demand for a suction amount for sucking water from a base material containing an aqueous liquid.
  • Patent Documents 1 to 4 disclose a water absorbent resin composition containing a modifier having a hydrocarbon group having a fluorine atom.
  • Patent Document 6 discloses a polyaminoalkylsiloxane complex as a water-containing gel
  • Non-Patent Document 1 discloses a water-containing gel using a cylindrical polysiloxane as a raw material.
  • International Publication No. 2005/077500 pamphlet released on August 18, 2005
  • Japanese Patent Gazette “Special Publication 2006-526691 Publication Date: November 24, 2006”
  • Japanese Patent Gazette “Special Publication No. 8-509522 Publication Date: October 8, 1996)
  • Japanese Patent Gazette “Special Table 2004-512165 Publication Date: April 22, 2004
  • Japanese Patent Publication “Japanese Patent Laid-Open No. 2003-082250 Publication Date: March 19, 2003
  • Japanese Patent Publication “JP 2005-120333 A Publication Date: May 12, 2005)” J. Mater. Chem., 2006, 16, 1746-1750
  • polysiloxane is used as a cross-linking agent, polysiloxane is generally hardly soluble in water and has a water-insoluble property, so it hardly dissolves in a polymerization reaction solution using water as a medium and is uniform. There is a disadvantage that polymerization cannot be performed in the state. For this reason, a simple manufacturing method has not been established.
  • the polymer may be exposed to high temperatures in the drying process and the surface cross-linking process, and the polymer may deteriorate. Accordingly, there is a demand for a water-absorbing agent having heat resistance, which does not cause a decrease in performance of the water-absorbing agent obtained by deterioration of the raw material polymer.
  • the present invention has been made in view of the above-mentioned conventional problems, and an object thereof is to provide an unprecedented water-absorbing agent using a compound having a polysiloxane structure. Furthermore, it is providing the water absorbing agent which has heat resistance.
  • the water-absorbing agent of the present invention is characterized by containing a water-absorbing resin having a structural unit derived from an acid group-containing unsaturated monomer and a water-soluble polysiloxane having a dissociating group in order to solve the above-mentioned problems. .
  • a novel water-absorbing agent containing the water-soluble polysiloxane can be provided. That is, in the water-absorbing agent, the water-soluble polysiloxane is water-soluble, and an organic-inorganic composite in which the water-absorbing resin and the organic-inorganic structure are uniformly crosslinked can be provided. Further, by newly providing a water-absorbing agent having a water-soluble polysiloxane, the possibility of a new design of the water-absorbing agent can be expanded. Moreover, the water-absorbing agent obtained is excellent in saline flow conductivity. Furthermore, since the water-absorbing agent contains an inorganic structure derived from polysiloxane in its structure, it also has heat resistance.
  • the dissociating group is preferably an amino group.
  • the water-absorbing resin having a structural unit derived from an acid group-containing unsaturated monomer and the amino group are chemically bonded to each other and / or the surface of the water-absorbing resin. Can be easily provided.
  • the water-absorbent resin is internally cross-linked by the water-soluble polysiloxane.
  • Such a configuration can provide a new water-absorbing agent that is internally cross-linked with a water-soluble polysiloxane.
  • the surface of the water-absorbent resin is surface-crosslinked with the water-soluble polysiloxane.
  • Such a configuration can provide a water-absorbing agent whose surface is cross-linked with a water-soluble polysiloxane.
  • the water-absorbing resin is preferably formed by polymerizing an unsaturated monomer containing a carboxyl group.
  • the water-soluble resin having a carboxylic acid has a dissociation group of the water-soluble polysiloxane and a carboxyl group of the water-absorption resin.
  • the water-soluble polysiloxane has the following chemical formulas (1) to (4): [Q (H x ⁇ Z) ⁇ (R 1 ) 2 N (CH 2 ) n SiO 1.5 ] p [C j H 2j + 1 OSiO 1.5 ] 1-P Chemical formula (1) [Q (H x ⁇ Z) ⁇ (R 1) 2 N (CH 2) n SiO 1.5 ] p [CH 3 (CH 2) m SiO 1.5 ] 1-P ⁇ ⁇ ⁇ formula (2) [Q (H x ⁇ Z) ⁇ (R 1 ) 2 N (CH 2 ) n SiO 1.5 ] p [R 2 SiO 1.5 ] 1-P ...
  • Chemical formula (3) [Q (H x ⁇ Z) ⁇ (R 1 ) 2 N (CH 2 ) n SiO 1.5 ] p [R 3 NH (CH 2 ) n SiO 1.5 ] 1-P ( 1 )
  • Chemical formula (4) (In the above chemical formulas (1) to (4), n is independently an integer of 1 or more and 6 or less, j is an integer of 0 or more and 4 or less, and m is Any integer of 0 or more and 4 or less, p is independently a value in the range of more than 0 and 1 or less, and R 1 is independently a hydrogen atom, an alkyl group, or a substituted alkyl group.
  • R 2 is a hydrogen atom, a vinyl group or an allyl group
  • Z is a monovalent or divalent anion
  • q is a value multiplied by the neutralization rate
  • R 1 contains an amino group
  • 0.1 or more is a number in the range of 2 or less, if R 1 does not include an amino group, of 0.1 or more and 1 or less
  • x is 1 when Z is a monovalent anion, preferably has at least one of the molecular structure represented by Z is 2 when divalent anion.).
  • the water-soluble polysiloxane has at least one of the molecular structures represented by the chemical formulas (1) to (4), it is easy to synthesize the water-soluble polysiloxane, and the water-absorbing agent is more easily produced. can do.
  • p in the chemical formulas (1) to (4) is preferably 0.3 or more and 1 or less.
  • the water solubility of the monomer used as the raw material for the water-soluble polysiloxane is improved.
  • more uniform mixing with these solvents can be achieved.
  • R 1 is preferably a hydrogen atom and n is preferably 3. That is, in each chemical formula of the water-soluble polysiloxane, the structure [H 2 N (CH 2 ) 3 SiO 1.5 ] p is provided, whereby a water-absorbing agent having excellent water absorption characteristics can be provided. .
  • one R 1 is a hydrogen atom
  • the other R 1 is a 2-aminoethyl group
  • q is It is a number in the range of 0.1 to 2 and x is preferably 1.
  • the solid content with respect to 100 parts by mass of the water-absorbing agent is preferably 70 parts by mass or more.
  • the solid content is less than the above range, not only the fluidity is deteriorated and the production may be hindered, but the water absorbent resin may not be pulverized and may not be controlled to a specific particle size distribution. .
  • the absorbent article according to the present invention is obtained by using 0.001 part by mass or more and 10 parts by mass or less of the water-soluble polysiloxane with respect to 100 parts by mass of the acid group-containing unsaturated monomer. preferable.
  • the absorbent article according to the present invention contains the above water-absorbing agent.
  • the water-absorbing agent is a novel water-absorbing agent containing the water-soluble polysiloxane, a new absorbent article can be provided.
  • the method for producing a water-absorbing agent according to the present invention comprises a hydrogel crosslinked polymer obtained by crosslinking polymerization of an acid group-containing unsaturated monomer in the presence of an internal crosslinking agent.
  • a water-soluble polysiloxane having an amino group is used as the internal crosslinking agent.
  • the inside of the water-absorbent resin is cross-linked with the water-soluble polysiloxane, and thus a novel water-absorbing agent containing the water-soluble polysiloxane is produced. can do.
  • the method for producing a water-absorbing agent according to the present invention comprises a hydrogel crosslinked polymer obtained by crosslinking polymerization of an acid group-containing unsaturated monomer in the presence of an internal crosslinking agent.
  • the method for producing a water-absorbing agent drying to obtain a water-absorbing agent, the water-containing gel-like crosslinked polymer is dried, and the obtained water-containing gel-like crosslinked polymer dried product is used with a water-soluble polysiloxane having an amino group. It is characterized by surface-treating a dried hydrogel crosslinked polymer.
  • the dried hydrogel crosslinked polymer after the surface treatment can be crosslinked with the water-soluble polysiloxane via a covalent bond and / or an ionic bond.
  • a novel water-absorbing agent containing improved water-soluble polysiloxane can be produced.
  • the method for producing a water-absorbing agent according to the present invention comprises a hydrogel crosslinked polymer obtained by crosslinking polymerization of an acid group-containing unsaturated monomer in the presence of an internal crosslinking agent.
  • drying to obtain a water-absorbing agent after drying the water-containing gel-like crosslinked polymer and subjecting the obtained water-containing gel-like crosslinked polymer dried product to surface crosslinking treatment, It is characterized by adding a water-soluble polysiloxane having a water-soluble gel-like crosslinked polymer dried product subjected to a surface crosslinking treatment.
  • the surface of the dried hydrogel crosslinked polymer can be crosslinked with the water-soluble polysiloxane by the action of the water-soluble polysiloxane as the surface treatment agent, and a novel water-absorbing agent containing the water-soluble polysiloxane is produced. can do.
  • the water-soluble polysiloxane has the following chemical formulas (1) to (4): [Q (H x ⁇ Z) ⁇ (R 1 ) 2 N (CH 2 ) n SiO 1.5 ] p [C j H 2j + 1 OSiO 1.5 ] 1-P Chemical formula (1) [Q (H x ⁇ Z) ⁇ (R 1) 2 N (CH 2) n SiO 1.5 ] p [CH 3 (CH 2) m SiO 1.5 ] 1-P ⁇ ⁇ ⁇ formula (2) [Q (H x ⁇ Z) ⁇ (R 1 ) 2 N (CH 2 ) n SiO 1.5 ] p [R 2 SiO 1.5 ] 1-P ...
  • Chemical formula (3) [Q (H x ⁇ Z) ⁇ (R 1 ) 2 N (CH 2 ) n SiO 1.5 ] p [R 3 NH (CH 2 ) n SiO 1.5 ] 1-P ( 1 )
  • Chemical formula (4) (In the above chemical formulas (1) to (4), n is independently an integer of 1 or more and 6 or less, j is an integer of 0 or more and 4 or less, and m is Any integer of 0 or more and 4 or less, p is independently a value in the range of more than 0 and 1 or less, and R 1 is independently a hydrogen atom, an alkyl group, or a substituted alkyl group.
  • R 2 is a hydrogen atom, a vinyl group or an allyl group
  • R 3 is an acryloyl group or a methacryloyl group
  • Z is a monovalent or divalent anion
  • q is neutralized
  • R 1 includes an amino group
  • the number is in the range of 0.1 to 2
  • R 1 does not include an amino group
  • the value is in the range of 0.1 to 1
  • X is 1 when Z is a monovalent anion and Z is a divalent anion In the case of emissions is 2.
  • It preferably has at least one molecular structure represented by
  • the water-soluble polysiloxane has at least one of the molecular structures represented by the chemical formulas (1) to (4), it is easy to synthesize the water-soluble polysiloxane, and the water-absorbing agent is more easily produced. can do.
  • the water-absorbing agent according to the present invention contains a water-absorbing resin having a structural unit derived from an acid group-containing unsaturated monomer and a water-soluble polysiloxane having a dissociating group.
  • the water absorbent resin is crosslinked with polysiloxane. It is sufficient that at least one of the surface or the inside of the water absorbent resin is crosslinked.
  • each compound and water absorbing agent used for obtaining the water absorbing agent according to the present invention will be described.
  • the water-soluble polysiloxane according to the present invention may be simply referred to as polysiloxane.
  • weight is treated as a synonym for “mass”
  • weight% is treated as a synonym for “mass%”.
  • Water-absorbing resin in the present invention, a water-absorbing resin obtained by crosslinking and polymerizing an acid group-containing unsaturated monomer and a water-soluble polysiloxane described later are essential.
  • the water-absorbing resin may be a water-absorbing resin having a cross-linked polymerization structure, and after the acid group and / or its salt-containing unsaturated monomer is polymerized, it undergoes a cross-linking reaction by self-crosslinking during polymerization or polymerization.
  • the obtained water-absorbent resin may be used.
  • the water-absorbent resin has a structural unit derived from an acid group-containing unsaturated monomer, and preferably has the structural unit as a main component. “Having as a main component” means containing 90% or more of the total mass of the water-absorbent resin.
  • structural unit derived from an acid group-containing unsaturated monomer means, for example, an acid in which a double bond part involved in polymerization of an acid group-containing unsaturated monomer is converted to a single bond by a polymerization reaction. The structure of the group-containing unsaturated monomer will be shown.
  • the water-absorbent resin according to the present invention is a water-swellable and water-insoluble crosslinked polymer capable of forming a hydrogel.
  • the water-swellable water-absorbing resin refers to one that absorbs a large amount of water in ion-exchanged water essentially 5 times or more of its own weight, preferably 50 to 1000 times.
  • the water-insoluble water-absorbent resin is preferably an uncrosslinked water-soluble component (water-soluble polymer) in the water-absorbent resin, preferably 50% by mass or less (lower limit 0%), more preferably 25% by mass or less. It is preferably 20% by mass or less, particularly preferably 15% by mass or less, and most preferably 10% by mass or less.
  • crosslinked polymer is a polymer having a crosslinked structure (hereinafter referred to as “internal crosslinked structure”) inside a polymer obtained by polymerizing an unsaturated monomer in order to obtain good absorption characteristics. Refers to coalescence.
  • the water-absorbent resin has a structural unit derived from an acid group-containing unsaturated monomer.
  • the water-soluble polysiloxane has a dissociating group.
  • the dissociating group includes both a proton accepting group and a proton donating group. Specific examples include an amino group, a carboxyl group, a sulfonic acid group, a sulfate ester group, and a phosphoric acid group, and an amino group is preferable.
  • the water-soluble polysiloxane according to the present invention preferably has an amino group as a dissociating group.
  • the amino group of the said water-soluble polysiloxane and the carboxyl group of a water absorbing resin will carry out a chemical bond (covalent bond, ionic bond), and inside a water absorbing resin and / Or the surface can be cross-linked.
  • the water-absorbent resin may be subjected to a surface cross-linking treatment that forms a cross-linked structure on the surface of the water-absorbent resin, or may not be subjected to the surface cross-linking treatment.
  • a surface crosslinking treatment is performed.
  • water-absorbing resin comprising the above-mentioned crosslinked polymer
  • examples of the water-absorbing resin comprising the above-mentioned crosslinked polymer include polyacrylic acid partially neutralized polymer, starch-acrylonitrile graft polymer hydrolyzate, starch-acrylic acid graft polymer or neutralized product thereof, carboxy Cross-linked methylcellulose, saponified product of vinyl acetate-acrylic ester copolymer, hydrolyzate of acrylonitrile copolymer or acrylamide copolymer or cross-linked product thereof, carboxyl group-containing cross-linked polyvinyl alcohol modified product, cross-linked cationic monomer 1 type or 2 types or more, such as a crosslinked product of 2-acrylamido-2-methylpropanesulfonic acid and acrylic acid, and a crosslinked isobutylene- (maleic anhydride) copolymer.
  • the water-absorbing resin composed of the above-mentioned crosslinked polymer is obtained by polymerizing and crosslinking an unsaturated monomer, and is subjected to surface crosslinking treatment as necessary.
  • the water-soluble polysiloxane, unsaturated monomer, crosslinkable monomer (internal crosslinker), polymerization initiator, surface crosslinker and the like used for the production of the water absorbent resin will be described.
  • the water-soluble polysiloxane is a water-soluble polysiloxane having a dissociation group.
  • a dissociation group preferably an amino group
  • water-solubility is exhibited, and a water-absorbing agent can be provided by reaction with a water-absorbing resin.
  • the water-absorbing agent can include a polysiloxane structure, a new water-absorbing agent can be designed.
  • the polysiloxane has a dissociation group, preferably an amino group, which the general polysiloxane does not have in the molecular structure. Therefore, the polysiloxane according to the present invention can exhibit water solubility, and can be used by dissolving in an aqueous solution or a highly polar solvent.
  • Water solubility means that a solution of 0.1 g or more, preferably 1 g or more, is dissolved in 100 g of pure water to give a transparent and uniform solution. Furthermore, it can couple
  • the surface treatment agent As the surface treatment agent, the surface of the water-absorbent resin can be cross-linked through covalent bonds and / or ionic bonds by allowing polysiloxane to act on the surface of the surface-crosslinked water-absorbent resin.
  • a water-absorbing agent having an unprecedented structure can be obtained.
  • the water-soluble polysiloxane is not particularly limited, but has a dissociation group, preferably an amino group, and is essential to be water-soluble.
  • a dissociation group preferably an amino group
  • the water-soluble polysiloxane will be described in more detail.
  • the water-soluble polysiloxane will be described mainly with respect to a molecular structure having an amino group.
  • the polysiloxane of the present invention only needs to have a dissociating group, and the amino group portion is replaced with the dissociating group described above. Can be configured.
  • the water-soluble polysiloxane according to the present invention has the following chemical formula (1) to chemical formula (4) as its molecular structure.
  • Chemical formula (1) [Q (H x ⁇ Z) ⁇ (R 1) 2 N (CH 2) n SiO 1.5 ] p [CH 3 (CH 2) m SiO 1.5 ] 1-P ⁇ ⁇ ⁇ formula (2) [Q (H x ⁇ Z) ⁇ (R 1 ) 2 N (CH 2 ) n SiO 1.5 ] p [R 2 SiO 1.5 ] 1-P ...
  • Chemical formula (3) [Q (H x ⁇ Z) ⁇ (R 1 ) 2 N (CH 2 ) n SiO 1.5 ] p [R 3 NH (CH 2 ) n SiO 1.5 ] 1-P ( 1 )
  • Chemical formula (4) (In the above chemical formulas (1) to (4), n is independently an integer of 1 or more and 6 or less, j is an integer of 0 or more and 4 or less, and m is Any integer of 0 or more and 4 or less, p is independently a value in the range of more than 0 and 1 or less, and R 1 is independently a hydrogen atom, an alkyl group, or a substituted alkyl group.
  • R 2 is a hydrogen atom, a vinyl group or an allyl group
  • R 3 is an acryloyl group or a methacryloyl group
  • Z is a monovalent or divalent anion
  • q is neutralized
  • R 1 includes an amino group
  • the number is in the range of 0.1 to 2
  • R 1 does not include an amino group
  • the value is in the range of 0.1 to 1
  • X is 1 when Z is a monovalent anion and Z is a divalent anion For emission is 2.
  • the water-soluble polysiloxane having the molecular structure as described above can be synthesized relatively easily. For this reason, it becomes possible to manufacture the water absorbing agent containing the said water-soluble polysiloxane more simply.
  • n, j, and m are in the above-mentioned range, that is, the structure has a structure in which the hydrophobicity of the polysiloxane is difficult to improve.
  • P representing the proportion of each repeating unit in the above chemical formulas (1) to (4) is preferably 0.3 or more and 1 or less, more preferably 0.5 or more and 1 or less. It is particularly preferably 9 or more and 1 or less.
  • the water-solubility of the polysiloxane improves, so that it is particularly easy to dissolve in water or a hydrophilic solvent, so that more uniform mixing with these solvents can be achieved.
  • polysiloxane when polysiloxane is used as a raw material for the water-absorbing agent, it can be efficiently used in the reaction in a solution state, and the water-absorbing agent can be easily obtained.
  • each R 1 is independently a hydrogen atom, an alkyl group, or an allyl group.
  • the alkyl group may be unsubstituted, or a substituent containing any of an amino group, an epoxy group or an unsaturated group may be introduced.
  • An alkyl group into which a substituent is introduced is referred to as a substituted alkyl group.
  • an unsaturated group shows the molecular structure containing a double bond or a triple bond.
  • alkyl group examples include a linear alkyl group such as methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, and undecyl. Group, dodecyl group and the like.
  • the allyl group is not particularly limited as long as it contains a 2-propenyl group.
  • the alkyl group and allyl group may be substituted with a substituent containing any of an amino group, an epoxy group, or an unsaturated group, but the substitution position is not particularly limited.
  • the structure in which an alkyl group is substituted with an amino group includes an aminomethyl group, an aminomethyl group, an aminopropyl group, an aminobutyl group, an aminopentyl group, an aminohexyl group, an aminoheptyl group, an aminooctyl group, an aminononyl group, Examples include aminodecyl group, aminoundecyl group, aminododecyl group, and isomers thereof.
  • a 3-aminopropyl group in which R 1 is all hydrogen atoms and n is 3 is more preferable because the raw materials are easily available.
  • R 2 in the chemical formula (3) is a hydrogen atom, a vinyl group or an allyl group.
  • the allyl group is the same allyl group as the allyl group in R 1 described above.
  • Z is a monovalent or divalent anion
  • q is a value obtained by multiplying the neutralization rate
  • R 1 contains an amino group
  • 0.1 The number is in the range of 2 or less and when R 1 does not contain an amino group, the number is in the range of 0.1 or more and 1 or less.
  • R 1 when R 1 includes an amino group, the number of Z coordinated on nitrogen can be doubled compared to when R 1 does not include an amino group.
  • each nitrogen contains one atom, so the neutralization rate is a number in the range of 0.1 to 1 Yes, q is also a number in the range of 0.1 to 1.
  • Z when R 1 contains an amino group, Z can be coordinated to 1 or 2 atoms in the nitrogen contained in R 1 , and neutralization is a number in the range of 0.1 to 1 Multiply the rate by a factor of 2, and the maximum value of q is 2 or less. That is, q is a number in the range from 0.1 to 2.
  • a molecular structure of an amine structure that is not an ammonium salt is included at a ratio of q-1.
  • the monovalent or divalent anion is not particularly limited as long as the properties of the water-absorbing agent obtained when the water-soluble polysiloxane is allowed to act on the water-absorbing resin are not impaired.
  • Specific examples include chloride ions, nitrate ions, sulfate ions, carboxylate anions, and phosphonate anions.
  • the structure of the hydrocarbon bonded to the anion moiety is a hydrocarbon having 1 to 12 carbon atoms, and even a straight chain structure has a side chain structure. You may do it.
  • the polysiloxane structure in the chemical formulas (1) to (4) may be an amine structure.
  • the water absorbent resin and the polysiloxane can be bonded via a covalent bond and / or an ionic bond.
  • the structures of the chemical formulas (1) to (4) are respectively [(R 1 ) 2 N (CH 2 ) n SiO 1.5 ] p [C j H 2j + 1 OSiO 1.5 ] 1-P— Chemical formula (1 ′) [(R 1 ) 2 N (CH 2 ) n SiO 1.5 ] p [CH 3 (CH 2 ) m SiO 1.5 ] 1-P ...
  • the mass average molecular weight of the polysiloxane is not particularly limited, but in the case of an ammonium salt structure, it is preferably 5000 or more and 1000000 or less. When the mass average molecular weight is less than 5000, and when it exceeds 1000000, there is a possibility that sufficient absorption characteristics of the resulting water-absorbing agent may not be obtained.
  • the method for producing polysiloxane is not limited to the following method, and may be a method described in Japanese Patent Publication “JP-A-2005-120333” or Japanese Patent Publication “JP-A-2006-45392”. .
  • the polysiloxane used in the present invention includes at least one of the structures represented by the chemical formulas (1) to (4). These chemical formulas (1) to (4) each contain a structure of [q (H x ⁇ Z) ⁇ (R 1 ) 2 N (CH 2 ) n SiO 1.5 ].
  • this structure is referred to as a basic structure for convenience of explanation.
  • [C j H 2j + 1 OSiO 1.5 ], [CH 3 (CH 2 ) m SiO 1.5 ], [R 2 SiO, which are structural parts other than the basic structures of chemical formulas (1) to (4). 1.5 ] and [R 3 NH (CH 2 ) n SiO 1.5 ] are referred to as substructure (1), substructure (2), substructure (3) and substructure (4), respectively.
  • the compound that is a monomer that is a raw material of the basic structure, the substructure (1), the substructure (2), the substructure (3), and the substructure (4) will be described.
  • n in chemical formula (5) is an integer of 1 or more and 6 or less, and R 1 has the same chemical structure as R 1 described above in ⁇ Water-soluble polysiloxane>.
  • R 4 is not particularly limited as long as it is an alkyl group. Specific examples of R 4 include a methyl group, an ethyl group, and a propyl group.
  • R 1 is hydrogen, aminomethylmethoxysilane, aminomethylethoxysilane, aminomethylpropoxysilane, 2-aminoethylmethoxysilane, 2-aminoethylethoxysilane, Examples include 2-aminoethylpropoxysilane, 3-aminopropylmethoxysilane, 3-aminopropylethoxysilane, 3-aminopropylpropoxysilane, and the like. Among these, 3-aminopropylmethoxysilane, 3-aminopropylethoxysilane, and 3-aminopropylpropoxysilane can be preferably used because they are easily available.
  • R 1 may be an alkyl group or an allyl group exemplified above other than a hydrogen atom.
  • Examples of compounds in which one R 1 is a hydrogen atom and the other R 1 has a 2-aminoethyl group include 3- (2-aminoethylamino) propyltrimethoxysilane, 3- (2-aminoethylamino) Mention may be made of propyltriethoxysilane and 3- (2-aminoethylamino) propyltripropoxysilane.
  • the allyl group can be further introduced by using a compound having an unsaturated carbonyl group such as acrylic chloride.
  • R 5 is the same structure as the alkyl group exemplified as R 4 in the compound represented by the above chemical formula (5). However, R 4 and R 5 do not have to be the same, and may have different structures. This is because when polysiloxane is produced, the structure containing R 4 is removed from the final product by an elimination reaction.
  • specific compounds include, but are not limited to, tetramethoxysilane, tetraethoxysilane, and tetrapropoxysilane.
  • Representative examples of specific compounds include methyltrimethoxysilane, methyltriethoxysilane, methyltripropoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, ethyltripropoxysilane, propyltrimethoxysilane, and propyltriethoxy.
  • Examples include silane, propyltripropoxysilane, butyltrimethoxysilane, butyltriethoxysilane, butyltripropoxysilane, pentyltrimethoxysilane, pentyltriethoxysilane, and pentyltripropoxysilane.
  • R 2 Si (OR 7 ) 3 Chemical formula (8)
  • the allyl trialkoxysilane shown by these can be used.
  • R 2 is a hydrogen atom, a vinyl group or an allyl group
  • the allyl group is the same as the allyl group which R 1 in the chemical formulas (1) to (4) may have.
  • the structure of R 7 is the same structure as the alkyl group exemplified as R 4 in the compound represented by the above chemical formula (5). However, R 4 and R 7 do not have to be the same, and may have different structures.
  • Representative examples of specific compounds include vinyltrimethoxysilane, vinyltriethoxysilane, vinyltripropoxysilane, (2-propenyl) methyltrimethoxysilane, (2-propenyl) methyltriethoxysilane, (2- (Propenyl) methyltripropoxysilane, (2-propenyl) ethyltrimethoxysilane, (2-propenyl) ethyltriethoxysilane, (2-propenyl) ethyltripropoxysilane, (2-propenyl) propyltrimethoxysilane, (2- Propenyl) propyltriethoxysilane, (2-propenyl) propyltripropoxysilane, and the like, but are not limited thereto.
  • the compound used as a raw material for the substructure (4) is not particularly limited as long as it can generate the substructure (4).
  • Substructure (4) is generated by reacting amines such as silane and 3-aminopropylpropoxysilane, and acrylic group-introducing compounds such as acryloid chloride or methacrylic group-introducing compounds such as methacryloyl chloride. be able to.
  • p in the chemical formulas (1) to (4) is independently 0.
  • a polysiloxane having a value exceeding 1 and not more than 1 can be obtained.
  • the ratio of the raw materials of the basic structure, substructure (1), substructure (2), substructure (3) and substructure (4) (hereinafter referred to as “polysiloxane raw material”) is particularly limited. However, as the ratio of the raw material of the polysiloxane to the raw material of the basic structure increases, the value of p in the chemical formulas (1) to (4) of the resulting polysiloxane decreases, and the hydrophilicity of the polysiloxane decreases. In order to reduce, it is preferable that the ratio of the raw material of a basic structure is larger than the total amount of the raw material of polysiloxane.
  • the ratio of each raw material is set so that the value of p is preferably 0.3 or more and 1 or less, more preferably 0.5 or more and 1 or less, and particularly preferably 0.9 or more and 1 or less. It is preferable to adjust.
  • the above raw materials are dropped into an acid in an aqueous solution in which an acid is present as a catalyst.
  • an acid hydrochloric acid, nitric acid and the like can be used.
  • the molar ratio of the total amount of the polysiloxane raw material and the acid can be in the range of 1: 1 to 1: 4.
  • the reaction temperature when the polysiloxane raw material is dropped into an aqueous solution containing an acid as a catalyst may be room temperature.
  • the time for polymerizing the polysiloxane raw material varies depending on the type of the polysiloxane raw material to be used, but the polymerization reaction may be generally carried out for 1 to 3 hours.
  • reaction mixture is placed in an open system at a temperature of about 50 ° C. to 80 ° C. to evaporate water from the reaction mixture.
  • This step can be performed using a conventionally known dryer or the like.
  • the polysiloxane contained in the mixture after evaporation of water may be used as a raw material for the water-absorbing agent after being purified, but if there is no problem in the process of producing the water-absorbing agent, it is used without being purified. Also good.
  • Examples of a method for purifying polysiloxane include a method in which the above mixture is dissolved in distilled water and an organic solvent is added to make use of the difference in solubility. As the organic solvent is added, the polysiloxane precipitates. The polysiloxane can be purified by filtering this precipitate.
  • the method for producing the water-absorbing agent according to the present invention can be broadly classified as follows: a step of polymerizing monomers, a polymer obtained by polymerizing the obtained monomers, that is, water content It is divided into a step of drying the gel-like crosslinked polymer and a step of surface cross-linking.
  • the water-absorbing resin containing the water-soluble polysiloxane can be produced by including the water-soluble polysiloxane described above in the water-absorbing resin.
  • step of polymerizing the monomer the step of adding a water-soluble polysiloxane as an internal cross-linking agent to the aqueous solution when polymerizing the monomer (ii)
  • step of surface cross-linking treatment step of adding water-soluble polysiloxane as a surface cross-linking agent (iv)
  • the water-absorbing resin cross-linked with the water-soluble polysiloxane Step of adding siloxane A polymerization step, a drying step, and a surface treatment step included in the method for producing a water absorbing agent will be described below.
  • the acid group-containing unsaturated monomer used to obtain the water-absorbing resin contained in the water-absorbing agent of the present invention is a compound that can obtain a desired crosslinked polymer.
  • a saturated monomer may be used.
  • the unsaturated monomer is water-soluble, a solution reaction with a water-soluble polysiloxane described later can be smoothly performed by aqueous solution polymerization.
  • an unsaturated monomer having an acid form and / or a salt molecular structure thereof can be used.
  • the acid group include a carboxyl group, a sulfo group, an amide group, and an ester group.
  • the acid group-containing unsaturated monomer examples include vinyl sulfonic acid, ⁇ -acryloyloxypropionic acid, methacrylic acid, (anhydrous) maleic acid, fumaric acid, crotonic acid, itaconic acid, vinyl sulfonic acid,
  • Examples include acid group-containing simple substances such as 2- (meth) acrylamido-2-methylpropanesulfonic acid and (meth) acryloxyalkanesulfonic acid, and alkali metal salts, ammonium salts and alkylamine salts thereof.
  • the water-absorbent resin is a polymer of partially neutralized acrylic acid
  • acrylic acid and / or a salt thereof neutralized product
  • other unsaturated monomers other than acrylic acid and / or salt thereof may be included as a copolymerization component.
  • other properties such as antibacterial properties and deodorization can be imparted to the finally obtained water absorbent resin, and the water absorbent resin can be obtained at a lower cost.
  • Examples of the other unsaturated monomers include N-vinyl-2-pyrrolidone, N-vinylacetamide, (meth) acrylamide, N-isopropyl (meth) acrylamide, N, N-dimethyl (meth) acrylamide, 2-hydroxy
  • Examples thereof include water-soluble or water-insoluble unsaturated monomers such as ethyl (meth) acrylate, methoxypolyethylene glycol (meth) acrylate, polyethylene glycol (meth) acrylate, isobutylene, and lauryl (meth) acrylate. These monomers may use only 1 type and may mix and use 2 or more types suitably.
  • Examples of the acid group-containing unsaturated monomer of the present invention include those having the other unsaturated monomer as a copolymerization component.
  • alkali metal salts Alkali metal salts, alkaline earth metal salts, ammonium salts, preferably alkali metal salts may be used.
  • sodium salt or potassium salt should be used at least essential from the viewpoint of the performance of the water-absorbing resin obtained, the industrial availability of the salt of the acid group-containing unsaturated monomer, safety, etc. preferable.
  • the number of moles of acrylic acid and its salt as the main component is preferably 70 to 100 mole% with respect to the total number of moles of all unsaturated monomers used to obtain the water-absorbent resin. More preferably, it is 90 to 100 mol%, and further preferably 95 to 100 mol%.
  • the acid group-containing unsaturated monomer such as acrylic acid is preferably about neutral from the viewpoint of physical properties and pH, and the acid group is preferably neutralized.
  • the neutralization rate of acid groups (mol% of neutralized acid groups in all acid groups) is usually 20 to 100 mol%, preferably 30 to 95 mol%, more preferably 40 to 80 mol%.
  • the neutralization of the acid group may be performed with a monomer, a polymer, or a combination thereof.
  • the water-absorbent resin of the present invention is a cross-linked polymer having an internal cross-linked structure.
  • the internal cross-linking structure of the water-absorbent resin may be obtained by self-crosslinking of an unsaturated monomer without using a cross-linking monomer that is an internal cross-linking agent.
  • those obtained by copolymerizing or reacting the unsaturated monomer and the crosslinking monomer are preferable.
  • the cross-linking monomer as an internal cross-linking agent has two or more polymerizable unsaturated groups or two or more reactive groups in one molecule.
  • the above-described polysiloxane can be used as an internal cross-linking agent.
  • the unsaturated monomer and the polysiloxane can be reacted by the dissociation group portion contained in the polysiloxane, and the polysiloxane structure is formed inside the resulting water-absorbent resin. It is possible to provide a water-absorbing agent having
  • the polysiloxane contains an unsaturated group
  • addition polymerization can occur with the monomer, so that variations in the crosslinking method can be increased, and the crosslinking structure can be increased. Different water-absorbing agents can be obtained.
  • Other internal crosslinking agents include, for example, N, N′-methylenebis (meth) acrylamide, (poly) ethylene glycol di (meth) acrylate, (poly) propylene glycol di (meth) acrylate, trimethylolpropane tri (meta) ) Acrylate, glycerin tri (meth) acrylate, glycerin acrylate methacrylate, ethylene oxide modified trimethylolpropane tri (meth) acrylate, pentaerythritol hexa (meth) acrylate, triallyl cyanurate, triallyl isocyanurate, triallyl phosphate, triallylamine , Poly (meth) allyloxyalkane, (poly) ethylene glycol diglycidyl ether, glycerol diglycidyl ether, ethylene glycol, polyethylene Glycol, propylene glycol, glycerol, pentaerythritol,
  • the above internal cross-linking agents may be used alone or in combination of two or more. Moreover, the said internal crosslinking agent may be added to a reaction system all at once, and may be divided and added.
  • a cross-linkable monomer having two or more polymerizable unsaturated groups is used in consideration of the absorption characteristics of the finally obtained water-absorbing agent. It is preferably used at the time of polymerization.
  • the amount used when the polysiloxane is used as an internal crosslinking agent is 0.001 mass relative to 100 parts by mass of the acid group-containing unsaturated monomer (excluding the crosslinking agent) used to obtain the water-absorbent resin. It is preferably no less than 10.0 parts by mass, more preferably no less than 0.01 parts by mass and no greater than 5 parts by mass, and particularly preferably no less than 0.1 parts by mass and no greater than 1 part by mass. .
  • the amount of the internal crosslinking agent used is less than 0.001 part by mass, and when it exceeds 10 parts by mass, it is not preferable because sufficient absorption characteristics of the water absorbing agent may not be obtained.
  • the amount of the internal crosslinking agent other than the polysiloxane used is the total number of moles of unsaturated monomers used to obtain the water absorbent resin (crosslinking agent is from the viewpoint of obtaining good physical properties of the water absorbent resin. Is preferably 0.001 to 2 mol%, more preferably 0.005 to 0.5 mol%, still more preferably 0.01 to 0.2 mol%, and particularly preferably 0.03 to 0 mol%. Within the range of 15 mol%. When the amount of the internal cross-linking agent used is less than 0.001 mol% and exceeds 2 mol%, it is not preferable because sufficient absorption characteristics of the water absorbing agent may not be obtained.
  • the internal crosslinking agent is added to the reaction system before, during or after the polymerization of the unsaturated monomer, or after neutralization. What is necessary is just to add.
  • the polysiloxane may be added to the reaction system after polymerization.
  • a water-containing gel-like crosslinked polymer is heated, a water-containing gel-like crosslinked polymer can be dried and internal crosslinking can be caused.
  • the unsaturated monomer is an aqueous solution containing an internal cross-linking agent as necessary.
  • concentration of the unsaturated monomer component in the aqueous monomer solution is preferably 10 to 70% by mass, more preferably 15 to 65% by mass, still more preferably 30 to 65% by mass, particularly preferably from the viewpoint of physical properties. Is 30 to 60% by mass, most preferably 35 to 55% by mass.
  • a solvent other than water may be used in combination as necessary, and the type of solvent used in combination is not particularly limited.
  • the mixing method is not particularly limited, but is preferably added to the monomer or aqueous monomer solution and mixed to be unsaturated. It is adjusted to a monomer aqueous solution.
  • the water-soluble polysiloxane when used as a crosslinkable monomer, from the viewpoint that the water-soluble polysiloxane can be uniformly mixed in the polymerization reaction solution and the polymerization can be easily controlled. It is preferable to perform aqueous solution polymerization or reverse phase suspension polymerization by making the body into an aqueous solution.
  • the reverse phase suspension polymerization is a polymerization method in which an aqueous monomer solution is suspended in a hydrophobic organic solvent in the form of particles.
  • a hydrophobic organic solvent in the form of particles.
  • aqueous solution polymerization is a method of polymerizing an aqueous monomer solution without using a dispersion solvent.
  • US Pat. Nos. 4,462,001, 4,873,299, 4,286,082, 4,973,632, 4,985,518, and 5,124,416 are used.
  • No. 5,250,640, No. 5,264,495, No. 5,145,906 and No. 5,380,808, and European patents such as European Patent Nos. 081636, 09555086, and 0922717.
  • Monomers and polymerization initiators exemplified in these US patents and European patents can also be applied to the present invention.
  • the concentration of the monomer in the aqueous solution depends on the temperature of the aqueous solution and the monomer and is particularly limited. is not. However, it is usually in the range of 10 to 80% by mass, preferably in the range of 10 to 70% by mass, and more preferably in the range of 20 to 60% by mass. Moreover, when performing the said aqueous solution polymerization, you may use together solvents other than water as needed, and the kind of solvent used together is not specifically limited.
  • the above polymerization initiator can be used.
  • active energy rays such as ultraviolet rays, electron beams, and ⁇ rays may be used alone or in combination with the polymerization initiator.
  • the reaction temperature in the above polymerization reaction depends on the type of polymerization initiator used, but is preferably in the range of 15 to 130 ° C., more preferably in the range of 20 to 120 ° C., as the lower limit to the upper limit temperature during the polymerization. If the reaction temperature is out of the above range, the water absorption performance of the water absorbent resin may be deteriorated due to an increase in residual monomers of the obtained water absorbent resin or excessive self-crosslinking reaction, which is not preferable.
  • a water-soluble polysiloxane is adjusted to the above amount and mixed with an aqueous monomer solution during polymerization.
  • the monomer aqueous solution at the time of polymerization is not limited to the monomer aqueous solution before polymerization, and is a concept including a monomer aqueous solution in the middle of polymerization and a gel-like substance containing the water solubility. It may be added one or more times at a stage where the rate is 0 to 99 mol%, further 0 to 70 mol%, particularly 0 to 50 mol%.
  • water-soluble polysiloxane when added to the monomer aqueous solution in the polymerization step, it can be mixed at any timing before and after the introduction of the polymerization initiator, and the timing and method of mixing are particularly limited. However, it is preferably added to the monomer aqueous solution (polymerization rate 0%) before polymerization.
  • hydrogel The hydrogel crosslinked polymer obtained in the polymerization process (hereinafter, hydrogel) may be dried as it is in the case of aqueous solution polymerization, but if necessary, a gel grinder or the like may be used.
  • the gel is pulverized into particles.
  • the temperature of the water-containing gel at the time of gel pulverization is preferably kept at 40 to 95 ° C., more preferably 50 to 80 ° C. from the viewpoint of physical properties.
  • the resin solid content of the hydrated gel is not particularly limited, but is preferably 10 to 70% by mass, more preferably 15 to 65% by mass, and further preferably 30 to 55% by mass from the viewpoint of physical properties.
  • the gel pulverization is performed at the time of polymerization or after polymerization, and can be preferably pulverized by extrusion from a continuous kneader or a porous structure having a pore diameter of 0.3 to 30 mm, more preferably 5 to 30 mm, and even more preferably 5 to 20 mm. .
  • the shape of the hole is not particularly limited, such as a quadrangle such as a circle, a square, and a rectangle, a triangle, and a hexagon. However, the hole is preferably extruded from a circular hole.
  • the said hole diameter can be prescribed
  • the gel may become a string or the gel may not be extruded.
  • the pore diameter of the porous structure is larger than 30 mm, the water-containing gel is not sufficiently dried, so that the effects of the present invention may not be exhibited.
  • the extrusion pulverization apparatus for example, a screw type, a rotary roll type, or the like that can pressure-feed the hydrogel polymer from its supply port to the perforated plate is used.
  • the screw-type extruder may be uniaxial or multi-axial, and may normally be used for extrusion molding of meat, rubber and plastic, or may be used as a pulverizer.
  • meat chopper and dome gran are mentioned.
  • water or a polyhydric alcohol described in the example of the internal cross-linking agent a mixed solution of water and polyhydric alcohol, a solution in which the polyvalent metal described in the example of the internal cross-linking agent is dissolved in water, or a vapor thereof is added. May be.
  • a water-soluble polysiloxane is mixed at the time of sizing (subdividing) the water-containing gel.
  • the polymer obtained by polymerizing the monomer by the above polymerization method is usually a hydrogel crosslinked polymer, and is subjected to drying treatment or pulverization as necessary.
  • the grinding is usually performed before and / or after the drying process.
  • a dried hydrogel crosslinked polymer can be obtained.
  • the drying method includes heat drying, hot air drying, vacuum drying, infrared drying, microwave drying, dehydration by azeotropy with a hydrophobic organic solvent, and high moisture drying using high-temperature steam.
  • Various methods can be adopted so as to be, and there is no particular limitation.
  • the drying treatment is performed by hot air drying, it is usually performed in a temperature range (hot air temperature) of 60 ° C. to 250 ° C., preferably 100 ° C. to 220 ° C., more preferably 120 ° C. to 200 ° C.
  • the drying time depends on the surface area of the polymer, the moisture content, and the type of dryer, and is selected to achieve the desired moisture content. For example, the drying time may be appropriately selected within the range of 1 minute to 5 hours.
  • Water content of the water-absorbent resin that can be used in the present invention (specified by the amount of water contained in the water-absorbent resin or water-absorbing agent / measured for 3 hours of loss on drying at 180 ° C.
  • the ratio expressed by the ratio to the resin is not particularly limited. However, in order to obtain good physical properties of the water-absorbing agent of the present invention containing the water-absorbing resin as a main component, it is preferable that the water content is controllable so that particles (powder) exhibiting fluidity at room temperature.
  • the water-absorbing agent is preferably in a powder state with a water content of 0 to 30% by mass, more preferably in a powder state of 0.2 to 30% by mass, more preferably in a powder state of 0.2 to 20% by mass,
  • the powder state is preferably 0.3 to 15% by mass, and particularly preferably 0.5 to 10% by mass.
  • What is necessary is just to dry-process a water-containing gel-like crosslinked polymer, and to obtain a water absorbing resin so that the water absorbing agent which has the water content in said range may be obtained. If the water content becomes high, the fluidity is deteriorated and the production is hindered, and the water-absorbent resin cannot be pulverized and may not be controlled to a specific particle size distribution.
  • the hydrogel crosslinked polymer obtained after the completion of the polymerization reaction is usually dispersed in a hydrocarbon organic solvent such as hexane. After azeotropic dehydration, the water content of the polymer is adjusted to 40% by mass or less (lower limit 0% by mass, preferably 5% by mass), preferably 30% by mass or less, and then separated from the organic solvent by decantation or evaporation. Depending on the case, it can be dried.
  • the water-absorbent resin of the present invention may be added and mixed with a surface cross-linking agent, a liquid permeability improver, a slipperiness improver, etc., which will be described later, during or after polymerization.
  • a surface cross-linking agent e.g., a liquid permeability improver, a slipperiness improver, etc., which will be described later, during or after polymerization.
  • the addition and mixing can be performed before drying, after drying or after pulverization.
  • the particle size may be adjusted after drying after the step of drying the water-containing gel-like crosslinked polymer described above, but it is preferably specified for improving the physical properties in surface crosslinking described later.
  • the particle size can be appropriately adjusted by polymerization (particularly reversed phase suspension polymerization), pulverization, classification, granulation, fine powder recovery and the like.
  • the mass average particle diameter (D50) before surface crosslinking is adjusted to 200 to 600 ⁇ m, preferably 200 to 550 ⁇ m, more preferably 250 to 500 ⁇ m, and particularly preferably 350 to 450 ⁇ m. Further, the smaller the particle size is less than 150 ⁇ m, the better, and it is usually adjusted to 0 to 5% by mass, preferably 0 to 3% by mass, particularly preferably 0 to 1% by mass. Further, the smaller the number of particles of 850 ⁇ m or more, the better. Usually, it is adjusted to 0 to 5% by mass, preferably 0 to 3% by mass, particularly preferably 0 to 1% by mass.
  • the logarithmic standard deviation ( ⁇ ) of the particle size distribution is preferably 0.20 to 0.40, preferably 0.27 to 0.37, and preferably 0.25 to 0.35.
  • the surface cross-linking of the water-absorbent resin is to provide a uniform cross-linked structure inside the polymer with a portion having a higher cross-linking density in the surface layer of the water-absorbent resin (near the surface: usually several tens of microns or less) That is, a highly crosslinked layer may be formed by radical crosslinking or surface polymerization on the surface, or surface crosslinking may be performed by a crosslinking reaction with a surface crosslinking agent.
  • the surface cross-linking by the surface cross-linking agent performed as necessary in the present invention will be further described.
  • the surface cross-linking agent used in the present invention includes various organic or inorganic cross-linking agents. From the viewpoint of physical properties, cross-linking agents capable of reacting with carboxyl groups, particularly organic surface cross-linking agents, generally polyhydric alcohols. Compounds, epoxy compounds, polyvalent amine compounds or their condensates with haloepoxy compounds, oxazoline compounds, mono-, di- or polyoxazolidinone compounds, polyvalent metal salts, alkylene carbonate compounds, and the like are used.
  • the polysiloxane has a dissociation group, preferably an amino group, it can react with a functional group of the water-absorbent resin and can crosslink the surface of the water-absorbent resin. Thereby, a water-absorbing agent containing polysiloxane can be obtained, and a new water-absorbing agent surface-crosslinked with polysiloxane can be provided.
  • the surface cross-linking agent other than the polysiloxane a compound having two or more functional groups capable of reacting with the functional group of the water-absorbent resin can be used as the surface cross-linking agent.
  • a compound having two or more functional groups capable of reacting with the functional group of the water-absorbent resin can be used as the surface cross-linking agent.
  • polyhydric alcohol compounds, epoxy compounds, polyepoxy compounds, polyvalent amine compounds or their condensates with haloepoxy compounds, oxazoline compounds, mono-, di- or polyoxazolidinone compounds, polyvalent metal salts, alkylene A carbonate compound or the like can be used.
  • surface cross-linking agent used in the present invention are exemplified in US Pat. Nos. 6,228,930, 6071976, and 6254990.
  • mono, di, tri, tetra or polyethylene glycol monopropylene glycol, 1,3-propanediol, dipropylene glycol, 2,3,4-trimethyl-1,3-pentanediol, polypropylene glycol, glycerin, polyglycerin , 2-butene-1,4-diol, 1,4-butanediol, 1,3-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,2-cyclohexanedimethanol, etc.
  • Alcohol compounds epoxy compounds such as ethylene glycol diglycidyl ether and glycidol, ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, polyethyleneimine, polyamide polyamine, etc.
  • Haloepoxy compounds such as epichlorohydrin, epibromohydrin, ⁇ -methylepichlorohydrin; condensates of the above polyvalent amine compounds with the above haloepoxy compounds, xazolidinone compounds such as 2-oxazolidinone, ethylene carbonate Examples thereof include, but are not limited to, alkylene carbonate compounds.
  • the amount of the surface cross-linking agent used depends on the compounds used, combinations thereof, and the like, but is preferably in the range of 0.001 to 10 parts by mass with respect to 100 parts by mass of the resin solids, 0.01 mass More preferably within the range of 5 parts by mass to 5 parts by mass.
  • water is preferably used for surface crosslinking.
  • the amount of water used depends on the water content of the water-absorbing resin to be used, it is usually preferably 0.5 to 20 parts by weight, more preferably 0.8 parts per 100 parts by weight of the water-absorbing resin. It is in the range of 5 to 10 parts by mass.
  • the amount of the surface cross-linking agent used is preferably in the range of 0.001 to 10 parts by mass with respect to 100 parts by mass (parts by mass) of the water-absorbing resin, although it depends on the compounds to be used and combinations thereof. A range of 0.01 parts by mass to 5 parts by mass is more preferable.
  • the amount of water used depends on the water content of the water absorbent resin to be used, but is preferably 0.5 to 20 parts by mass, more preferably 0.5 to 10 parts by mass with respect to 100 parts by mass of the water absorbent resin. Within the range of parts by mass.
  • a hydrophilic organic solvent may be used instead of water, or a mixed solvent of water and a hydrophilic organic solvent may be used.
  • the amount of the hydrophilic organic solvent or mixed solvent used in this case is in the range of 0 to 10 parts by weight, preferably 0 to 5 parts by weight, more preferably 0 to 3 parts by weight with respect to 100 parts by weight of the water absorbent resin. It is.
  • the addition of the surface cross-linking agent can be performed by various methods. However, a method in which the surface cross-linking agent is preliminarily mixed with water and / or a hydrophilic organic solvent, if necessary, and then sprayed or dropped into the water-absorbent resin is preferable, and a method of spraying is more preferable.
  • the size of droplets to be sprayed is preferably in the range of 0.1 to 300 ⁇ m, more preferably in the range of 0.1 to 200 ⁇ m, in terms of average particle diameter.
  • the mixing device used when mixing the water-absorbing resin, the surface cross-linking agent, and water or a hydrophilic organic solvent has a large mixing force in order to mix these substances uniformly and reliably. It is preferable.
  • the mixing apparatus include a cylindrical mixer, a double wall conical mixer, a high-speed stirring mixer, a V-shaped mixer, a ribbon mixer, a screw mixer, a double-arm kneader, and a pulverizing kneader. Rotating mixers, airflow mixers, turbulators, batch-type Redige mixers, continuous-type Redige mixers, and the like are suitable.
  • the surface cross-linking agent When mixing the surface cross-linking agent, it may be mixed with a polymer additive having a hydrocarbon group having 7 or more carbon atoms in the side chain before the surface cross-linking or coexisting with the surface cross-linking agent.
  • the water-absorbing agent of the invention can be obtained.
  • water-insoluble fine particle powder when mixing the surface cross-linking agent, water-insoluble fine particle powder may be allowed to coexist within a range that does not hinder the effects of the present invention.
  • the water-absorbing resin after mixing the surface cross-linking agent is preferably heat-treated.
  • the heating temperature water absorbent resin temperature or heat medium temperature
  • the heating time is preferably in the range of 1 minute to 2 hours.
  • Preferable examples of the combination of the heating temperature and the heating time are 180 ° C. for 0.1 to 1.5 hours and 200 ° C. for 0.1 to 1 hour.
  • the surface cross-linking treatment in the present invention there is a method of performing surface cross-linking treatment by irradiating active energy after adding a treatment liquid containing a radical polymerizable compound to the water absorbent resin. It is described in a national published patent publication “Japanese Patent Laid-Open No. 2003-303306”. Moreover, a surface active agent can also be added to the said process liquid, and an active energy can be irradiated and surface crosslinking can also be performed.
  • the water-soluble gel-like crosslinked polymer obtained by subjecting the water-containing gel-like polymer to surface cross-linking treatment is allowed to act on the water-soluble polysiloxane according to the present invention
  • the surface of the dried hydrogel crosslinked polymer can be surface-crosslinked by covalent bonding and / or ionic bonding. Also by this, the water absorbing agent containing polysiloxane can be obtained.
  • the timing which makes water-soluble polysiloxane act on a hydrogel crosslinked polymer dried material is not specifically limited.
  • a method for allowing polysiloxane to act on the surface-crosslinked water-absorbing resin is not particularly limited.
  • polysiloxane may be dissolved in water or a hydrophilic organic solvent and mixed with the water-absorbing resin.
  • a mixing apparatus for example, a cylindrical mixer, a double wall cone mixer, a high-speed stirring mixer, a V-shaped mixer, a ribbon mixer, a screw mixer, a double-arm kneader, a pulverizing kneader, A rotary mixer, an airflow mixer, a turbulizer, a batch-type Redige mixer, a continuous-type Redige mixer, and the like are suitable.
  • the amount of water-soluble polysiloxane used is preferably in the range of 0.01 to 20 parts by mass, more preferably in the range of 0.1 to 10 parts by mass, with respect to 100 parts by mass of the water-absorbing resin.
  • the water-soluble polysiloxane is made into a solution for uniform addition, further an aqueous solution or an aqueous solution, and added as a solution to the surface-crosslinked water-absorbing resin.
  • concentration of the solution may be 1 to 50% by mass.
  • a hydrophilic organic solvent may be used.
  • ⁇ Other components contained in water-absorbing agent> a surfactant, a deodorant, an antibacterial agent, a fragrance, a foaming agent, a pigment, a dye, a hydrophilic short fiber, a plasticizer, an adhesive, a fertilizer, an oxidizing agent, Reducing agent, water, salt, chelating agent, bactericidal agent, anti-coloring agent, hydrophilic polymer such as polyethylene glycol and polyerylenimine, hydrophobic polymer such as paraffin, thermoplastic resin such as polyethylene and polypropylene, polyester resin And a step of adding various functions such as addition of a thermosetting resin such as urea resin.
  • the amount of these additives to be used is usually 0 to 30 parts by weight, preferably 0 to 10 parts by weight, more preferably 0 to 1 part by weight with respect to 100 parts by weight of the water absorbent resin.
  • the mixing method of the water-absorbing agent and these additives is not particularly limited.
  • a dry blend method in which powders are mixed with each other, a wet blend method (addition is performed by dispersing or dissolving the additive in a solvent), etc. are adopted. it can.
  • the water-absorbing agent according to the present invention is obtained.
  • the present invention is not limited to the above-described embodiments, and various modifications are possible within the scope shown in the claims, and the present invention can be obtained by appropriately combining technical means disclosed in different embodiments. Such embodiments are also included in the technical scope of the present invention.
  • the water-absorbing agent according to the present invention contains a water-absorbing resin having a structural unit derived from an acid group-containing unsaturated monomer and a water-soluble polysiloxane having a dissociating group, preferably an amino group. . More preferably, the water-soluble polysiloxane has at least one molecular structure represented by the chemical formulas (1) to (4).
  • the water-soluble polysiloxane having the amine structure is formed by, for example, a covalent bond between the water-soluble polysiloxane and the water-absorbent resin in the production process, and the elimination of hydrogen atoms and negative ions Z in the water-soluble polysiloxane. Arise.
  • the shape of the water-absorbing agent according to the present invention includes, for example, a sheet shape and a fiber shape, and particularly preferably a particle shape or a spherical shape.
  • the water absorbing agent may be a granulated product.
  • the water-absorbing agent of the present invention is used for absorption of water, various aqueous solutions, aqueous solutions such as urine and blood, and the pure component of the water-absorbing resin is used as the main component in all the components contained in the water-absorbing agent.
  • the content is usually 70% by mass (% by mass) or more and 100% by mass or less, more preferably 80% by mass or more and 100% by mass or less, and still more preferably 90% by mass or more and 100% by mass or less with respect to 100 parts by mass.
  • the fluidity may deteriorate and the production may be hindered, or the water absorbent resin may not be pulverized or controlled to a specific particle size distribution. There is.
  • the lower limit of the value in 30 minutes of the absorption capacity under non-pressurization (CRC / Centrifuge Retention Capacity) of the water-absorbing agent of the present invention with respect to a 0.90 mass% sodium chloride aqueous solution is preferably 10 g / g, more preferably 15 g / g, More preferably, it is 20 g / g.
  • capacitance (CRC) under no pressure of the water absorbing agent of this invention becomes like this.
  • the absorption capacity without load (CRC) of the water-absorbent resin before the surface crosslinking treatment is preferably controlled in the range of 10 to 60 g / g, more preferably 25 to 40 g / g.
  • the absorption capacity is reduced by the surface cross-linking.
  • it is necessary to suppress the decrease preferably at 95 to 50%, more preferably 90 to 60% of the absorption ratio before surface crosslinking.
  • the reduction in the absorption capacity may be appropriately adjusted depending on the type and amount of the crosslinking agent, reaction temperature, time, and the like.
  • the physiological saline flow inductivity is a value indicating the liquid permeability when the water-absorbing agent swells, and indicates that the larger the value, the higher the liquid permeability.
  • the water-absorbing agent obtained in the present invention is preferably 10 (10 ⁇ 7 ⁇ cm 3 ⁇ s ⁇ g ⁇ 1 ) or more, more preferably 30 (10 ⁇ 7 ⁇ cm 3 ⁇ s ⁇ g ⁇ 1 ) or more, further preferably Is more than 50 (10 ⁇ 7 ⁇ cm 3 ⁇ s ⁇ g ⁇ 1 ), particularly preferably 80 (10 ⁇ 7 ⁇ cm 3 ⁇ s ⁇ g ⁇ 1 ) or more, saline flow conductivity (SFC / Saline Flow Conductivity)
  • SFC / Saline Flow Conductivity saline flow conductivity
  • the value of the saline flow conductivity is not particularly limited, but the upper limit may be about 3000 (10 ⁇ 7 ⁇ cm 3 ⁇ s ⁇ g ⁇ 1 ).
  • AAP Absorption capacity under pressure
  • AAP (Absorbency against Pure) of the water-absorbing agent of the present invention is 8 (g / g) or more, preferably 16 (g / g) or more, more preferably 20 (g / g) or more. Yes, more preferably 22 (g / g) or more, and most preferably 24 (g / g) or more.
  • the water-soluble content of the water-absorbing agent of the present invention is preferably 0 to 35% by mass or less, more preferably 25% by mass or less, still more preferably 15% by mass or less, and particularly preferably 10% by mass or less.
  • the gel strength is weak and the liquid permeability may be inferior.
  • the absorption capacity (CRC, AAP, etc.) may decrease over time.
  • the solid content with respect to 100 parts by mass of the water-absorbing agent is preferably 70 parts by mass or more, more preferably 80 parts by mass or more, and particularly preferably 90 parts by mass or more.
  • the water-absorbing agent of the present invention preferably contains 90% by weight or more (upper limit of 100%) of particles having a particle size of 150 ⁇ m or more and less than 850 ⁇ m, more preferably 150 ⁇ m or more and less than 850 ⁇ m, based on the mass of the water-absorbing agent. Is contained in an amount of 95% by weight or more, and more preferably 98% by weight or more of particles of 150 ⁇ m or more and less than 850 ⁇ m.
  • the water-absorbing agent of the present invention is a water-absorbing agent mainly composed of a water-absorbing resin having a crosslinked structure obtained by polymerizing an unsaturated monomer, and the water-absorbing agent has a particle size of less than 850 ⁇ m and 150 ⁇ m or more. Is 90% by weight or more of the whole (the upper limit is 100% by weight).
  • the weight percent of the polysiloxane and the water-absorbing resin according to the present invention is preferably 80% by weight or more (upper limit is 100% by weight or less), more preferably 90% by weight or more, and still more preferably 95% by weight or more in the water-absorbing agent. Particularly preferred is 98% by weight or more.
  • the particle size of the water-absorbing agent is preferably 70% by weight or more (upper limit 100% by weight) of particles having a size of 250 ⁇ m or more.
  • the water-absorbing resin in the present invention and the water-absorbing agent obtained in the present invention are adjusted to a specific particle size in order to achieve the present invention, and preferably particles having a particle size of less than 850 ⁇ m and 150 ⁇ m or more (specified by sieve classification: JIS Z8801-1: 2000) is 90% by weight or more of the whole, more preferably, particles less than 850 ⁇ m and 150 ⁇ m or more are 95% by weight or more, more preferably less than 850 ⁇ m and particles of 150 ⁇ m or more are 98% by weight or more. It is. Moreover, it is preferable that the particle
  • the whole here means the whole water-absorbing resin or water-absorbing agent.
  • the particle size of 250 ⁇ m or more is preferably 70% by weight or more (upper limit 100% by weight), more preferably 75% by weight or more.
  • the weight average particle diameter (D50) of the water absorbent resin or water absorbent is preferably 200 to 600 ⁇ m, more preferably 300 to 600 ⁇ m, still more preferably 300 to 500 ⁇ m, particularly preferably 350 to 450 ⁇ m. If necessary, the particle diameter of the water-absorbing resin or water-absorbing agent may be adjusted by granulation.
  • the particle shape of the water-absorbing resin and water-absorbing agent thus obtained is not particularly limited, such as spherical, crushed, and irregular shapes, but is preferably an irregularly crushed one obtained through the pulverization step. Can be used.
  • the bulk specific gravity (specified in JIS K-3362: 1998) is preferably 0.40 to 0.80 g / ml, more preferably 0.50 to 0.75 g, in terms of the balance between liquid permeability and liquid uptake characteristics. / Ml, more preferably in the range of 0.60 to 0.73 g / ml.
  • the logarithmic standard deviation value ⁇ representing the particle size distribution is preferably in the range of 0.1 to 0.6, more preferably 0.2 to 0.5, still more preferably 0.25 to 0.40, and particularly preferably. It is in the range of 0.25 to 0.38.
  • the water-absorbing agent of the present invention that improves the fluidity of the powder
  • segregation becomes prominent in the hopper or bag, so that diapers, etc. It becomes easy to cause a variation in quality when it is incorporated into the product.
  • the particle size of 850 ⁇ m or more exceeds 10% by weight, the water absorption rate of the water-absorbing agent is slow, and when used in an absorbent article, the absorbent body feels bad, and a foreign body sensation appears, causing discomfort to the user. Is not preferable. Therefore, by adjusting the mass average particle diameter within the preferable range of the present invention, it is possible to obtain a water absorbing agent that is excellent in fluidity and bulk density, does not deteriorate water absorbing performance, and has no problems such as segregation.
  • the mass average particle diameter of the water-absorbing agent may be adjusted by adding and mixing insoluble fine particles or a hydrophilic solvent, preferably water, depending on the purpose and necessity, and further granulating.
  • the adjustment of the mass average particle diameter may be adjusted by dispersion polymerization and dispersion drying in the form of particles as in reverse phase suspension polymerization, but in the case of aqueous solution polymerization, etc., it is usually necessary to be ground and classified after drying.
  • the fine powder is recycled by granulation or the like to adjust to a specific mass average particle size.
  • the heat resistance of the water absorbing agent according to the present invention includes a polysiloxane structure and is excellent in heat resistance.
  • the heat resistance of the water-absorbing agent is evaluated visually based on whether or not the resulting water-absorbing agent is colored.
  • the water-absorbing agent has heat resistance, usually white, which is the color of the polymer, is observed. In this case, it can be determined that the water absorbing agent has not deteriorated in the manufacturing process.
  • the water-absorbing agent does not have heat resistance and the polymer is highly likely to be deteriorated.
  • the temperature in the manufacturing process of the water-absorbing agent is not particularly limited, and the heat-resistance depends on whether the water-absorbing agent is colored at the temperature related to the manufacturing process of the individual water-absorbing agent. Sex is observed.
  • the water-absorbing agent of the present invention is used for applications intended to absorb water and is widely used as an absorber or absorbent article.
  • body fluids such as urine and blood are used. It is suitably used as a sanitary material for absorption.
  • the absorbent body and absorbent article of the present invention comprise the water-absorbing agent of the present invention.
  • the absorber is an absorbent material molded mainly with a water-absorbing agent and hydrophilic fibers.
  • the said absorber is shape
  • the water absorbent content (core concentration) with respect to the total mass of the water absorbent and the hydrophilic fibers is preferably 20 to 100% by weight, more preferably 30 to 100% by weight, and still more preferably 40 to 100%. It is in the range of wt%.
  • core concentration of the water-absorbing agent is higher, the effect of lowering the absorption characteristics of the water-absorbing agent at the time of producing the absorbent body, a paper diaper or the like becomes more prominent.
  • the said absorbent article is an absorbent article provided with the said absorber, the surface sheet which has liquid permeability, and the back sheet
  • the manufacturing method of the said absorbent article first produces an absorber (absorption core) by blending or sandwiching a fiber material and a water absorbing agent, for example. Next, the absorbent body is sandwiched between a liquid-permeable top sheet and a liquid-impermeable back sheet, and if necessary, equipped with an elastic member, a diffusion layer, an adhesive tape, etc.
  • Absorbent articles especially adult paper diapers and sanitary napkins.
  • the absorbent body is used by being compression-molded in a range of density 0.06 to 0.50 g / cc and basis weight 0.01 to 0.20 g / cm 2 .
  • the fiber material used include hydrophilic fibers such as pulverized wood pulp, cotton linters and crosslinked cellulose fibers, rayon, cotton, wool, acetate, and vinylon. Preferably, they are airlaid.
  • the water-absorbent article of the present invention exhibits excellent absorption characteristics.
  • Specific examples of such absorbent articles include diapers for children, sanitary napkins, sanitary materials such as so-called incontinence pads, as well as adult paper diapers that have been growing rapidly in recent years. However, it is not limited to them.
  • the water-absorbent article according to the present invention has a small amount of return due to the excellent absorption characteristics of the water-absorbing agent present in the absorbent article, has a remarkably dry feeling, and greatly reduces the burden on the wearer and the caregiver. be able to.
  • parts by mass may be simply referred to as “parts” and “liters” may be simply referred to as “L”.
  • mass% may be described as “wt%”.
  • CRC centrifuge retention capacity
  • 0.200 g of the water-absorbing agent was uniformly put into a bag (85 mm ⁇ 60 mm) made of a nonwoven fabric (Nangoku Pulp Industries Co., Ltd., trade name: Heaton paper, model: GSP-22) and heat-sealed. It was immersed in an excess (usually about 500 ml) of 0.90% by mass saline (aqueous sodium chloride solution). After 30 minutes, the bag was pulled up and drained for 3 minutes with a centrifugal force (250 G) described in edana ABSORBENCY II 441.1-99 using a centrifuge (manufactured by Kokusan Co., Ltd., centrifuge: model H-122).
  • FIG. 1 is a schematic diagram showing an SFC measurement apparatus 20.
  • a glass tube 22 is inserted into the tank 21, and the lower end of the glass tube 22 is 5 cm above the bottom of the gel 34 in the cell 31 with 0.69 mass% saline solution 23. It is arranged so that it can be maintained at a height. Further, the 0.69 mass% saline solution 23 in the tank 21 is configured to be supplied to the cell 31 through the L-shaped tube 24 with a cock.
  • a collection container 38 that collects the permeated liquid is disposed below the cell 31, and the collection container 38 is installed on an upper pan balance 39. The inner diameter of the cell 31 is 6 cm.
  • a 400 stainless steel wire mesh (aperture 38 ⁇ m) 32 was installed.
  • Artificial urine (1) is calcium chloride dihydrate 0.25 g, potassium chloride 2.0 g, magnesium chloride hexahydrate 0.50 g, sodium sulfate 2.0 g, ammonium dihydrogen phosphate 0.85 g, What added 0.15 g of hydrogen ammonium diphosphate and 994.25 g of pure waters was used.
  • the water absorbing agent (0.900 g) uniformly placed in the container 30 is swollen for 60 minutes in an artificial urine (1) under a pressure of 2.07 kPa (0.3 psi) for 60 minutes. It was. Thereafter, the height of the gel layer of the gel 34 is recorded, and then a 0.69 mass% saline solution 23 is swollen from the tank 21 at a constant hydrostatic pressure under a pressure of 2.07 kPa (0.3 psi). The layers were passed through. This SFC test was performed at room temperature (20 ° C. or more and 25 ° C. or less).
  • the flow rate Fs (T) permeating the swollen gel 34 was determined in units of g / s by dividing the increased mass (g) by the increased time (s). Let Ts be the time at which a constant hydrostatic pressure and a stable flow rate were obtained, use only the data obtained between Ts and 10 minutes for the flow rate calculation, and use the flow rate obtained between Ts and 10 minutes.
  • the value of Fs (T 0), ie the initial flow rate through the gel layer, was calculated.
  • Fs (t 0): flow rate expressed in g / s
  • ⁇ density of NaCl solution (1.003 g / cm 3 )
  • A in cell 31
  • ⁇ P hydrostatic pressure applied to the gel layer (4920 dyne / cm 2 )
  • SFC value is (10 ⁇ 7 ⁇ cm 3 ⁇ s ⁇ g ⁇ 1 ).
  • a stainless steel 400 mesh wire mesh 101 (mesh size 38 ⁇ m) is fused to the bottom of a plastic support cylinder 100 having an inner diameter of 60 mm, and 0.900 g of water absorption is placed on the mesh. It was adjusted so that a load of 1.9 kPa (0.3 psi) or 4.8 kPa (0.7 psi) could be uniformly applied to the water-absorbent resin 102.
  • the piston 103 and the load 104 which have an outer diameter slightly smaller than 60 mm and do not cause a gap with the support cylinder and do not hinder vertical movement, are placed in this order, and a mass W3 (g) of this measuring device set is set. It was measured.
  • a glass filter 106 having a diameter of 90 mm (manufactured by Mutual Riken Glass Co., Ltd., pore diameter: 100 to 120 ⁇ m) is placed inside a petri dish 105 having a diameter of 150 mm, and physiological saline 108 (20 ° C. to 25 ° C.) is placed in the glass filter. It was added so as to be the same level as the top surface.
  • a sheet of filter paper 107 having a diameter of 90 mm (ADVANTEC Toyo Co., Ltd., product name: (JIS P 3801, No. 2), thickness 0.26 mm, retention particle diameter 5 ⁇ m) was placed so that the entire surface was wetted. Excess liquid was removed.
  • the above measuring device set was placed on the wet filter paper, and the liquid was absorbed under load. After 1 hour, the measuring device set was lifted and its mass W4 (g) was measured. And the absorption capacity
  • AAP (W4-W3) /0.9 ⁇ Amount of water-soluble component (water-soluble component)> Weigh out 184.3 g of 0.90 mass% saline in a plastic container with a capacity of 250 ml, add 1.00 g of water-absorbing agent to the aqueous solution, and rotate and stir the stirrer for 16 hours to dissolve the soluble content in the resin. Extracted. Filtration of this extract using 1 sheet of filter paper (ADVANTEC Toyo Co., Ltd., product name: (JISP 3801, No. 2), thickness 0.26 mm, retained particle diameter 5 ⁇ m) gave 50. 0 g was measured and used as a measurement solution.
  • a titration ([NaOH] ml, [HCl] ml) was determined by performing the same titration operation on the measurement solution.
  • the soluble content can be calculated by the following formula.
  • the average molecular weight of the monomer is calculated using the neutralization rate obtained by titration.
  • Soluble content (mass%) 0.1 ⁇ (average molecular weight) ⁇ 184.3 ⁇ 100 ⁇ ([HCl] ⁇ [bHCl]) / 1000 / 1.0 / 50.0
  • Neutralization rate (mol%) (1 ⁇ ([NaOH] ⁇ [bNaOH]) / ([HCl] ⁇ [bHCl])) ⁇ 100 ⁇ Granularity>
  • a water-absorbing resin or water-absorbing agent
  • JIS Z8801-1 (2000) JIS standard sieve of 850 ⁇ m, 710 ⁇ m, 600 ⁇ m, 500 ⁇ m, 425 ⁇ m, 300 ⁇ m, 212 ⁇ m, 150 ⁇ m, 106 ⁇ m, 45 ⁇ m.
  • Solid content (mass%) 100-moisture content (mass%)
  • the measurement method of solid content was performed as follows.
  • Solid content (mass%) ((W2 ⁇ W0) / W1) ⁇ 100 ⁇ Paint shaker test>
  • the paint shaker test (PS) is a paint shaker (Toyo Seisakusho Co., Ltd. Product No. 488) in which a glass container having a diameter of 6 cm and a height of 11 cm is filled with 10 g of glass beads having a diameter of 6 mm and a water-absorbing resin or a water-absorbing agent.
  • the details of the apparatus are disclosed in Japanese Patent Publication “Japanese Patent Laid-Open No. 9-235378”, which is shaken at 800 cycle / min (CPM).
  • the shaker time of 30 minutes is the paint shaker test 1 and the shake time is 10 minutes.
  • the glass beads are removed with a JIS standard sieve having an opening of 2 mm, and a damaged water-absorbing resin or water-absorbing agent is obtained.
  • polysiloxane (B) or (C) instead of the polysiloxane (A) was similarly evaluated for solubility in ion-exchanged water and solubility in a polymerization reaction solution.
  • polysiloxanes (A) to (C) have solubility in ion-exchanged water and polymerization reaction solution.
  • Example 1 In a polypropylene container having an inner diameter of 80 mm and a capacity of 1 liter, acrylic acid 257.6 g, polysiloxane (A) 2.0 mass% aqueous solution 1.58 g, and diethylenetriaminepentaacetic acid-5 sodium aqueous solution 1.0 mass% 1 A solution (A) in which .58 g is mixed, a solution (B) in which 215.2 g of a 48.5% by mass aqueous sodium hydroxide solution and 209.9 g of ion-exchanged water adjusted to 32 ° C. are mixed with a magnetic stirrer. While stirring, the solution (B) was quickly added to the solution (A) in an open system and mixed. A monomer aqueous solution having a liquid temperature increased to about 102 ° C. by heat of neutralization and heat of dissolution was obtained.
  • the stainless bat-shaped container had a bottom surface of 250 mm ⁇ 250 mm, a top surface of 640 mm ⁇ 640 mm, a height of 50 mm, a central cross section of a trapezoid, and an open top surface.
  • Polymerization started soon after the monomer aqueous solution was poured into the vat. Polymerization proceeded while generating water vapor and expanding and foaming up and down, left and right, and then contracted to a size slightly larger than the bottom surface. This expansion and contraction was completed within about 1 minute, and after holding in the polymerization vessel for 4 minutes, the water-containing polymer was taken out.
  • the obtained water-containing polymer was crushed with a meat chopper (ROYAL MEAT CHOPPER VR400K, manufactured by Iizuka Kogyo Co., Ltd.) having a die diameter of 9.5 mm to obtain a finely divided water-containing polymer.
  • the amount of gel charged was about 340 g / min, and pulverization was performed while deionized water was added at 48 g / min in parallel with gel charging.
  • the non-volatile content of the gel after pulverization was 50 to 55% by mass.
  • the finely divided hydrogel crosslinked polymer was spread on a 50 mesh wire net and dried with hot air at 180 ° C. for 35 minutes.
  • the dried product was pulverized with a roll mill, and further classified with a JIS standard sieve having an opening of 710 ⁇ m and an opening of 175 ⁇ m to obtain a water absorbing agent (1).
  • Example 2 The same operation was carried out by changing the amount of the 2.0 mass% aqueous solution of polysiloxane (A) of Example 1 to 157.5 g. Thus, a water absorbing agent (2) was obtained.
  • Example 3 The amount of the 2.0 mass% aqueous solution of the polysiloxane (A) in Example 1 was changed to 1.58 g, and 1.31 g (0.07 mol%) of polyethylene glycol diacrylate (molecular weight 523) was used in the same manner. Was performed. Thus, a water absorbing agent (3) was obtained.
  • Example 4 The amount of the 2.0 mass% aqueous solution of the polysiloxane (A) of Example 1 was changed to 15.75 g, and further using 1.31 g (0.07 mol%) of polyethylene glycol diacrylate (molecular weight 523), the same was performed. In this way, a water absorbing agent (4) was obtained.
  • Example 5 The same operation was performed by changing the polysiloxane (A) of Example 3 to the polysiloxane (B). In this way, a water absorbing agent (5) was obtained.
  • the obtained water-absorbing agent did not repel the liquid during water absorption. And since all the water absorbing agents obtained in the Examples were white without coloring, they were excellent in heat resistance capable of withstanding high temperature conditions during production.
  • Example 6 The same operation was performed by changing the polysiloxane (A) of Example 3 to polysiloxane (C). Thus, a water absorbing agent (6) was obtained.
  • the obtained water-absorbing agent did not repel the liquid during water absorption. And since the water-absorbing agent obtained in the examples was white without coloring, it was excellent in heat resistance capable of withstanding high-temperature conditions during production.
  • Example 1 A 2.0 mass% aqueous solution of the polysiloxane (A) of Example 1 was changed to 0 g, and the same operation was performed using 1.31 g (0.07 mol%) of polyethylene glycol diacrylate (molecular weight 523). . In this way, a comparative water absorbing agent (1) was obtained.
  • the water-absorbing agents (1) to (6) have an uncrosslinked water-soluble component (water-soluble polymer) of 28.7% or less and a centrifuge retention capacity (CRC) of 9
  • the polysiloxanes (A) to (C) act as internal crosslinking agents, and the water absorbing agents (1) to (6) have a crosslinked structure inside the polymer. I understand.
  • the polysiloxanes (A) to (C) act as crosslinking agents. I understand that. That is, it can be understood that a water-absorbing agent containing polysiloxane was obtained.
  • This finely divided hydrogel cross-linked polymer is spread on a 50-mesh wire mesh, dried with hot air at 180 ° C. for 45 minutes, the dried product is pulverized with a roll mill, and further classified by a JIS standard sieve having a mesh opening of 710 ⁇ m. The particles that have passed through are further classified with a JIS standard sieve having a mesh opening of 175 ⁇ m, and the fine particles that have passed through are removed, so that the mass average particle diameter (D50) is 343 ⁇ m and the logarithmic standard deviation ( ⁇ ) of 0.32 is not satisfied. A regularly crushed water-absorbing resin (A) was obtained.
  • Centrifuge retention capacity (CRC) of water-absorbent resin (A) is 33.4 (g / g), water-soluble content is 6.1% by mass, and the ratio of particles having a size that can pass through a sieve having an opening of 150 ⁇ m was 1.0 mass%.
  • a surface cross-linking agent composed of a mixed solution of 0.3 parts by mass of 1,4-butanediol, 0.5 parts by mass of propylene glycol and 2.7 parts by mass of pure water was uniformly mixed with 100 parts by mass of the obtained water absorbent resin.
  • the mixture was then heat treated at 212 ° C. for 35 minutes. Thereafter, the obtained particles were crushed until they passed through a JIS standard sieve having an opening of 710 ⁇ m. Next, a paint shaker test 1 was performed on the crushed particles. Thus, a water-absorbing resin (A) having a crosslinked surface was obtained.
  • Example 7 10 mass parts of 10.0 mass% aqueous solution of polysiloxane (A) was added to 100 mass parts of water absorbent resin (A). The addition was performed so that the solution was uniformly added while stirring the water absorbent resin (A). This mixture was left to dry at 60 ° C. for 30 minutes under no wind. In this manner, a water absorbing agent (7) was obtained.
  • the obtained water-absorbing agent did not repel the liquid during water absorption. And since the water-absorbing agent obtained in the examples was white without coloring, it was excellent in heat resistance capable of withstanding high-temperature conditions during production.
  • Example 8 To 100 parts by mass of the water-absorbent resin (A), a mixed solution consisting of 5.0 parts by mass of a 10.0 mass% aqueous solution of polysiloxane (A) and 5.0 parts by mass of propylene glycol was added. The addition was performed so that the solution was uniformly added while stirring the water absorbent resin (A). This mixture was left to dry at 60 ° C. for 30 minutes under no wind. In this manner, a water absorbing agent (8) was obtained.
  • the obtained water-absorbing agent did not repel the liquid during water absorption. And since the water-absorbing agent obtained in the examples was white without coloring, it was excellent in heat resistance capable of withstanding high-temperature conditions during production.
  • Example 9 To 100 parts by mass of the water-absorbent resin (A), a mixed solution consisting of 5.0 parts by mass of 10.0 mass% aqueous solution of polysiloxane (A) and 5.0 parts by mass of methanol was added. The addition was performed so that the solution was uniformly added while stirring the water absorbent resin (A). This mixture was left to dry at 60 ° C. for 30 minutes under no wind. In this manner, a water absorbing agent (9) was obtained.
  • Example 10 To 83.66 g of 0.5N hydrochloric acid, 4.50 g of 3-aminopropyltrimethoxysilane and 0.42 g of tetramethoxysilane were added dropwise. The solution was stirred at room temperature for 2 hours. The product was transferred to a dryer at 60 ° C. to evaporate and dry the water, and maintained at 100 ° C. for 10 to 16 hours to obtain a product. This product was designated as polysiloxane (D).
  • D polysiloxane
  • This polysiloxane (D) was made into a 10% by mass aqueous solution. This aqueous solution was a clear homogeneous solution.
  • the obtained water-absorbing agent did not repel the liquid during water absorption.
  • Table 3 shows the measurement results of CRC and SFC of the water-absorbing agents (7) to (10) and the comparative water-absorbing agents (2) to (4).
  • APTOMOS represents 3-aminopropyltrimethoxysilane
  • TMOS represents tetramethoxysilane.
  • the water-absorbing agent obtained from the present invention has high liquid permeability (saline flow inductivity) under pressure. Since the comparative water absorbing agent (2) obtained in Comparative Example 2 was not added with polysiloxane, its performance was not sufficient. Moreover, although the comparative water-absorbing agent (3) obtained in Comparative Example 3 is a water-soluble polysiloxane, its performance is not sufficient because it does not have a dissociating group. Finally, since the comparative water-absorbing agent (4) obtained in Comparative Example 4 is a polysiloxane having low water solubility, the performance is not sufficient and the liquid repels remarkably.
  • the water-absorbing agent of the present invention contains a water-absorbing resin having a structural unit derived from an acid group-containing unsaturated monomer and a water-soluble polysiloxane having a dissociating group.
  • a novel water-absorbing agent containing the above polysiloxane can be provided.
  • a water-absorbing agent having a polysiloxane it is possible to expand the possibility of a new design of the water-absorbing agent.
  • the obtained water absorbing agent has an effect that it is excellent in salt solution flow-inductivity.
  • a heat-absorbing water-absorbing agent can also be provided.
  • the water-absorbing agent of the present invention contains polysiloxane and can be used as a part of a new water-absorbing resin.
  • Absorbent articles made of such a water-absorbing agent can be widely used for hygiene materials such as adult paper diapers, children's diapers, sanitary napkins and so-called incontinence pads, which have been growing rapidly in recent years.

Abstract

Disclosed is a water absorbent comprising a water-absorbable resin having a constituent unit derived from an unsaturated monomer containing an acid group and a water-soluble polysiloxane having a dissociable group. Preferably, the water-soluble polysiloxane has a molecular structure represented by at least any one of the following chemical formulae (1) to (4): [q(Hx Z) (R1)2N(CH2)nSiO1.5]p[CjH2j+1OSiO1.5]1-p chemical formula (1); [q(Hx Z) (R1)2N(CH2)nSiO1.5]p[CH3(CH2)mSiO1.5]1-p chemical formula (2); [q(Hx Z) (R1)2N(CH2)nSiO1.5]p[R2SiO1.5]1-p chemical formula (3); and [q(Hx Z) (R1)2N(CH2)nSiO1.5]p[R3NH(CH2)nSiO1.5]1-p chemical formula (4). It becomes possible to provide a nonconventional water absorbent by using a compound having a polysiloxane structure.

Description

吸水剤およびその製造方法Water absorbing agent and method for producing the same
　本発明は、吸水性樹脂と解離基を有する水溶性ポリシロキサンと含む吸水剤及びその製造方法に関するものである。 The present invention relates to a water-absorbing agent containing a water-absorbing resin and a water-soluble polysiloxane having a dissociating group, and a method for producing the same.
　近年、吸水性樹脂は、体液（尿や血液）を吸収させることを目的として、紙おむつや生理用ナプキン、失禁パット等などの衛生材料（吸収物品）において、その主要な構成材料として幅広く利用されている。上記吸水性樹脂としては、例えば、ポリアクリル酸部分中和物架橋体、澱粉－アクリロニトリルグラフト重合体の加水分解物、澱粉－アクリル酸グラフト重合体の中和物、酢酸ビニル－アクリル酸エステル共重合体のケン化物、カルボキシメチルセルロース架橋体、アクリロニトリル共重合体若しくはアクリルアミド共重合体の加水分解物またはこれらの架橋体、カチオン性モノマーの架橋体、架橋イソブチレン－マレイン酸共重合体、２－アクリルアミド－２－メチルプロパンスルホン酸とアクリル酸との架橋体等が知られている。 In recent years, water-absorbent resins have been widely used as main constituent materials in hygiene materials (absorbent articles) such as disposable diapers, sanitary napkins, incontinence pads, etc. for the purpose of absorbing body fluids (urine and blood). Yes. Examples of the water-absorbing resin include a crosslinked polyacrylic acid partial neutralized product, a hydrolyzate of starch-acrylonitrile graft polymer, a neutralized product of starch-acrylic acid graft polymer, and a vinyl acetate-acrylic acid ester copolymer. Saponified product of polymer, crosslinked carboxymethyl cellulose, hydrolyzate of acrylonitrile copolymer or acrylamide copolymer or cross-linked product thereof, crosslinked product of cationic monomer, crosslinked isobutylene-maleic acid copolymer, 2-acrylamide-2 -A cross-linked product of methylpropanesulfonic acid and acrylic acid is known.
　従来、これら吸水剤に望まれる吸水特性としては、体液等の水性液体に接した際の高い吸収倍率、特に荷重下での高い吸水倍率、優れた吸収速度、通液性、膨潤ゲルのゲル強度、水性液体を含んだ基材から水を吸い上げる吸引量等が求められている。 Conventionally, water absorption characteristics desired for these water-absorbing agents include high absorption capacity when in contact with aqueous liquids such as body fluids, especially high water absorption capacity under load, excellent absorption rate, liquid permeability, gel strength of swollen gel There is a demand for a suction amount for sucking water from a base material containing an aqueous liquid.
　これら吸水性樹脂は、重合体内部に均一な架橋構造を持ち、水不溶化された親水性樹脂である。しかし、通常、上記の吸水特性を得るために、吸水性樹脂の粒子の表面をさらに架橋剤などで架橋処理することによって粒子に架橋密度勾配を持たせ、吸水性樹脂の吸水速度の向上、ママコの生成防止、ゲル強度の向上、加圧下での吸収倍率改善、ゲルブロッキング防止、通液性の向上が図られている（特許文献１～４）。これにより上記吸水性樹脂からなる吸水剤の吸水特性を向上させることを目的として、種々の改良がなされてきた。また、吸水性樹脂の改良の一環として、フッ素原子を有している炭化水素基を有する改質剤を含有する吸水性樹脂組成物が特許文献５に開示されている。 These water-absorbing resins are hydrophilic resins having a uniform cross-linked structure inside the polymer and insolubilized in water. However, in general, in order to obtain the above water absorption characteristics, the surface of the water absorbent resin particles is further subjected to a crosslinking treatment with a crosslinking agent to give the particles a crosslink density gradient, thereby improving the water absorption speed of the water absorbent resin. Prevention of gel formation, improvement in gel strength, improvement in absorption capacity under pressure, prevention of gel blocking, and improvement in liquid permeability (Patent Documents 1 to 4). Thus, various improvements have been made for the purpose of improving the water absorption characteristics of the water absorbent comprising the water absorbent resin. Moreover, as part of the improvement of the water absorbent resin, Patent Document 5 discloses a water absorbent resin composition containing a modifier having a hydrocarbon group having a fluorine atom.
　なお、吸水剤ではないが、含水ゲルとして、ポリアミノアルキルシロキサン複合体が特許文献６に、筒状のポリシロキサンを原料とした含水ゲルが非特許文献１に開示されている。
国際公開第２００５／０７５０７０号パンフレット（２００５年８月１８日公開） 日本国公表特許公報「特表２００６－５２６６９１号公報（公表日：平成１８年１１月２４日）」 日本国公表特許公報「特表平８－５０９５２２号公報（公表日：平成８年１０月８日）」 日本国公表特許公報「特表２００４－５１２１６５号公報（公表日：平成１６年４月２２日）」 日本国公開特許公報「特開２００３－０８２２５０号公報（公開日：平成１５年３月１９日）」 日本国公開特許公報「特開２００５－１２０３３３号公報（公開日：平成１７年５月１２日）」 J. Mater. Chem., 2006, 16, 1746-1750 Although not a water-absorbing agent, Patent Document 6 discloses a polyaminoalkylsiloxane complex as a water-containing gel, and Non-Patent Document 1 discloses a water-containing gel using a cylindrical polysiloxane as a raw material.
International Publication No. 2005/077500 pamphlet (released on August 18, 2005) Japanese Patent Gazette “Special Publication 2006-526691 (Publication Date: November 24, 2006)” Japanese Patent Gazette "Special Publication No. 8-509522 (Publication Date: October 8, 1996)" Japanese Patent Gazette “Special Table 2004-512165 (Publication Date: April 22, 2004)” Japanese Patent Publication “Japanese Patent Laid-Open No. 2003-082250 (Publication Date: March 19, 2003)” Japanese Patent Publication “JP 2005-120333 A (Publication Date: May 12, 2005)” J. Mater. Chem., 2006, 16, 1746-1750
　上記のように、これまで種々の吸水剤が開発されてきたが、従来にない吸水特性を有する吸水剤を得るためには、新たな構成の吸水剤を設計することが必要となる。そこで、本発明者らは、新たな吸水剤を得るために、通常用いられる有機系の架橋剤を用いて吸水性樹脂を架橋するのではなく、無機系の架橋剤を用いることを想到した。 As described above, various water-absorbing agents have been developed so far, but in order to obtain a water-absorbing agent having an unprecedented water-absorbing characteristic, it is necessary to design a water-absorbing agent having a new structure. Therefore, the present inventors have come up with the idea of using an inorganic cross-linking agent instead of cross-linking the water-absorbing resin using a commonly used organic cross-linking agent in order to obtain a new water-absorbing agent.
　ところで、無機系化合物による吸水性樹脂の架橋としては、アルミなどの多価金属イオンを用いて吸水性樹脂の架橋を行うことが可能であるが、この手法によって一般的に得られる吸水剤の吸水特性等は十分なものではない。また、架橋剤としてポリシロキサンを用いた場合、ポリシロキサンは一般的に水に非常に溶解し難い、水不溶性の性質を有するため、水を媒体とした重合反応液にほとんど溶解せず、均一な状態で重合ができないという欠点がある。このため、簡便な製造方法は確立されていない。 By the way, as the crosslinking of the water-absorbing resin with an inorganic compound, it is possible to cross-link the water-absorbing resin using a polyvalent metal ion such as aluminum. The characteristics are not sufficient. In addition, when polysiloxane is used as a cross-linking agent, polysiloxane is generally hardly soluble in water and has a water-insoluble property, so it hardly dissolves in a polymerization reaction solution using water as a medium and is uniform. There is a disadvantage that polymerization cannot be performed in the state. For this reason, a simple manufacturing method has not been established.
　また、吸水剤の製造工程では、乾燥工程、表面架橋工程において、ポリマーは高温に晒され、ポリマーの劣化が生じ得る。したがって、原料ポリマーの劣化によって得られる吸水剤の性能低下が生じない、耐熱性を有する吸水剤も要望されている。 Also, in the water-absorbing agent manufacturing process, the polymer may be exposed to high temperatures in the drying process and the surface cross-linking process, and the polymer may deteriorate. Accordingly, there is a demand for a water-absorbing agent having heat resistance, which does not cause a decrease in performance of the water-absorbing agent obtained by deterioration of the raw material polymer.
　本発明は、上記従来の問題点に鑑みなされたものであって、その目的は、ポリシロキサン構造を有する化合物を用いて、従来にない吸水剤を提供することにある。さらには、耐熱性を有する吸水剤を提供することにある。 The present invention has been made in view of the above-mentioned conventional problems, and an object thereof is to provide an unprecedented water-absorbing agent using a compound having a polysiloxane structure. Furthermore, it is providing the water absorbing agent which has heat resistance.
　本発明の吸水剤は、上記課題を解決するために、酸基含有不飽和単量体由来の構成単位を有する吸水性樹脂と、解離基を有する水溶性ポリシロキサンとを含むことを特徴としている。 The water-absorbing agent of the present invention is characterized by containing a water-absorbing resin having a structural unit derived from an acid group-containing unsaturated monomer and a water-soluble polysiloxane having a dissociating group in order to solve the above-mentioned problems. .
　上記の発明によれば、新規な上記水溶性ポリシロキサンを含んだ吸水剤を提供することができる。すなわち、上記吸水剤では、上記水溶性ポリシロキサンは水溶性であり、吸水性樹脂と有機-無機構造が均一に架橋された有機-無機複合体を提供することができる。また、新たに、水溶性ポリシロキサンを有する吸水剤を提供できることによって、吸水剤の新たな設計の可能性を拡張することができる。また、得られる吸水剤は食塩水流れ誘導性に優れる。さらに、上記吸水剤はその構造にポリシロキサン由来の無機構造を含むため、耐熱性をも有している。 According to the invention described above, a novel water-absorbing agent containing the water-soluble polysiloxane can be provided. That is, in the water-absorbing agent, the water-soluble polysiloxane is water-soluble, and an organic-inorganic composite in which the water-absorbing resin and the organic-inorganic structure are uniformly crosslinked can be provided. Further, by newly providing a water-absorbing agent having a water-soluble polysiloxane, the possibility of a new design of the water-absorbing agent can be expanded. Moreover, the water-absorbing agent obtained is excellent in saline flow conductivity. Furthermore, since the water-absorbing agent contains an inorganic structure derived from polysiloxane in its structure, it also has heat resistance.
　また、本発明に係る吸水剤では、上記解離基がアミノ基であることが好ましい。 In the water-absorbing agent according to the present invention, the dissociating group is preferably an amino group.
　このように、解離基がアミノ基であることによって、酸基含有不飽和単量体由来の構成単位を有する吸水性樹脂とアミノ基とが化学結合されることによって吸水性樹脂内部および／または表面が架橋された吸水剤を容易に提供することができる。 Thus, when the dissociating group is an amino group, the water-absorbing resin having a structural unit derived from an acid group-containing unsaturated monomer and the amino group are chemically bonded to each other and / or the surface of the water-absorbing resin. Can be easily provided.
　また、本発明に係る吸水剤では、上記吸水性樹脂が上記水溶性ポリシロキサンによって内部架橋されていることが好ましい。 In the water-absorbing agent according to the present invention, it is preferable that the water-absorbent resin is internally cross-linked by the water-soluble polysiloxane.
　このような構成により、水溶性ポリシロキサンによって内部架橋された新たな吸水剤を提供することができる。 Such a configuration can provide a new water-absorbing agent that is internally cross-linked with a water-soluble polysiloxane.
　また、本発明に係る吸水剤では、上記吸水性樹脂の表面が上記水溶性ポリシロキサンによって表面架橋されていることが好ましい。 In the water-absorbing agent according to the present invention, it is preferable that the surface of the water-absorbent resin is surface-crosslinked with the water-soluble polysiloxane.
　このような構成により、水溶性ポリシロキサンによって表面架橋された吸水剤を提供することができる。 Such a configuration can provide a water-absorbing agent whose surface is cross-linked with a water-soluble polysiloxane.
　また、本発明に係る吸水剤では、上記吸水性樹脂は、カルボキシル基を含有した不飽和単量体を重合してなることが好ましい。 In the water-absorbing agent according to the present invention, the water-absorbing resin is preferably formed by polymerizing an unsaturated monomer containing a carboxyl group.
　上記構成によれば、本発明に係る水溶性ポリシロキサンは解離基を有しているため、カルボン酸を有する吸水性樹脂であれば、上記水溶性ポリシロキサンの解離基と吸水性樹脂のカルボキシル基とが、化学結合（共有結合、イオン結合）することで、吸水性樹脂内部および／または表面を架橋することができる。 According to the above configuration, since the water-soluble polysiloxane according to the present invention has a dissociation group, the water-soluble resin having a carboxylic acid has a dissociation group of the water-soluble polysiloxane and a carboxyl group of the water-absorption resin. Can be cross-linked inside and / or on the surface of the water-absorbent resin through chemical bonds (covalent bonds, ionic bonds).
　本発明の吸水剤では、上記水溶性ポリシロキサンは、以下の化学式（１）～化学式（４）
　〔ｑ（Ｈｘ・Ｚ）・（Ｒ１）２Ｎ（ＣＨ２）ｎＳｉＯ１．５〕ｐ〔ＣｊＨ２ｊ＋１ＯＳｉＯ１．５〕１－Ｐ・・・化学式（１）
　〔ｑ（Ｈｘ・Ｚ）・（Ｒ１）２Ｎ（ＣＨ２）ｎＳｉＯ１．５〕ｐ〔ＣＨ３（ＣＨ２）ｍＳｉＯ１．５〕１－Ｐ・・・化学式（２）
　〔ｑ（Ｈｘ・Ｚ）・（Ｒ１）２Ｎ（ＣＨ２）ｎＳｉＯ１．５〕ｐ〔Ｒ２ＳｉＯ１．５〕１－Ｐ・・・化学式（３）
　〔ｑ（Ｈｘ・Ｚ）・（Ｒ１）２Ｎ（ＣＨ２）ｎＳｉＯ１．５〕ｐ〔Ｒ３ＮＨ（ＣＨ２）ｎＳｉＯ１．５〕１－Ｐ・・・化学式（４）
（上記化学式（１）～化学式（４）において、それぞれ独立して、ｎは１以上、６以下の何れかの整数であり、ｊは０以上、４以下の何れかの整数であり、ｍは０以上、４以下の何れかの整数であり、ｐはそれぞれ独立して、０を越え、１以下の範囲の値であり、Ｒ１はそれぞれ独立して、水素原子、アルキル基、置換アルキル基またはアリル基であり、Ｒ２は水素原子、ビニル基またはアリル基であり、Ｒ３は、アクリロイル基（－Ｃ（＝Ｏ）ＣＨ＝ＣＨ２）またはメタアクリロイル基（－Ｃ（＝Ｏ）Ｃ（ＣＨ３）＝ＣＨ２）であり、Ｚは１価もしくは２価の陰イオンであり、ｑは中和率を乗じた値であって、Ｒ１がアミノ基を含む場合、０．１以上２以下の範囲の数であり、Ｒ１がアミノ基を含まない場合、０．１以上１以下の範囲の数であり、ｘはＺが１価の陰イオンの場合１であり、Ｚが２価の陰イオンの場合２である。）で示される少なくとも何れかの分子構造を有することが好ましい。 In the water-absorbing agent of the present invention, the water-soluble polysiloxane has the following chemical formulas (1) to (4):
[Q (H x · Z) · (R 1 ) 2 N (CH 2 ) n SiO 1.5 ] p [C j H 2j + 1 OSiO 1.5 ] 1-P Chemical formula (1)
[Q (H x · Z) · (R 1) 2 N (CH 2) n SiO 1.5 ] p [CH 3 (CH 2) m SiO 1.5 ] 1-P · · · formula (2)
[Q (H x · Z) · (R 1 ) 2 N (CH 2 ) n SiO 1.5 ] p [R 2 SiO 1.5 ] 1-P ... Chemical formula (3)
[Q (H x · Z) · (R 1 ) 2 N (CH 2 ) n SiO 1.5 ] p [R 3 NH (CH 2 ) n SiO 1.5 ] 1-P ( 1 ) Chemical formula (4)
(In the above chemical formulas (1) to (4), n is independently an integer of 1 or more and 6 or less, j is an integer of 0 or more and 4 or less, and m is Any integer of 0 or more and 4 or less, p is independently a value in the range of more than 0 and 1 or less, and R 1 is independently a hydrogen atom, an alkyl group, or a substituted alkyl group. Or an allyl group, R 2 is a hydrogen atom, a vinyl group or an allyl group, and R 3 is an acryloyl group (—C (═O) CH═CH 2 ) or a methacryloyl group (—C (═O) C (CH 3 ) = CH 2 ), Z is a monovalent or divalent anion, q is a value multiplied by the neutralization rate, and when R 1 contains an amino group, 0.1 or more is a number in the range of 2 or less, if R 1 does not include an amino group, of 0.1 or more and 1 or less It is the number of enclosed, x is 1 when Z is a monovalent anion, preferably has at least one of the molecular structure represented by Z is 2 when divalent anion.).
　上記水溶性ポリシロキサンが上記化学式（１）～化学式（４）で示される少なくとも何れかの分子構造を有する場合、上記水溶性ポリシロキサンを合成することが簡便となり、上記吸水剤をより簡便に製造することができる。 When the water-soluble polysiloxane has at least one of the molecular structures represented by the chemical formulas (1) to (4), it is easy to synthesize the water-soluble polysiloxane, and the water-absorbing agent is more easily produced. can do.
　また、本発明に係る吸水剤では、上記化学式（１）～化学式（４）におけるｐが、０．３以上、１以下であることが好ましい。 In the water-absorbing agent according to the present invention, p in the chemical formulas (1) to (4) is preferably 0.3 or more and 1 or less.
　上記ｐがこの範囲であることによって、上記水溶性ポリシロキサンの原料となる単量体の水溶性が向上する。特に水または親水性溶媒に溶解させ易くなる結果、これらの溶媒とより均一な混合をさせることが可能となる。これにより、水溶性ポリシロキサンを吸水剤の原料として用いる際に、溶液の状態にて効率良く反応に用いることができ、容易に吸水剤を得ることが可能となる。 When the p is in this range, the water solubility of the monomer used as the raw material for the water-soluble polysiloxane is improved. In particular, as a result of being easily dissolved in water or a hydrophilic solvent, more uniform mixing with these solvents can be achieved. Thereby, when water-soluble polysiloxane is used as a raw material for the water-absorbing agent, it can be efficiently used in the reaction in a solution state, and the water-absorbing agent can be easily obtained.
　また、本発明に係る吸水剤では、上記化学式（１）～化学式（４）の各化学式において、Ｒ１が全て水素原子であり、ｎが３であることが好ましい。すなわち、上記水溶性ポリシロキサンの各化学式において、〔Ｈ２Ｎ（ＣＨ２）３ＳｉＯ１．５〕ｐの構造が備えられていることによって、吸水特性に優れた吸水剤を提供することができる。 In the water-absorbing agent according to the present invention, in the chemical formulas (1) to (4), R 1 is preferably a hydrogen atom and n is preferably 3. That is, in each chemical formula of the water-soluble polysiloxane, the structure [H 2 N (CH 2 ) 3 SiO 1.5 ] p is provided, whereby a water-absorbing agent having excellent water absorption characteristics can be provided. .
　また、本発明に係る吸水剤では、上記化学式（１）～化学式（４）の各化学式において、一方のＲ１が水素原子であり、他方のＲ１が２－アミノエチル基であり、ｑは０．１以上２以下の範囲の数であり、ｘが１であることが好ましい。 In the water-absorbing agent according to the present invention, in each of the chemical formulas (1) to (4), one R 1 is a hydrogen atom, the other R 1 is a 2-aminoethyl group, and q is It is a number in the range of 0.1 to 2 and x is preferably 1.
　すなわち、上記水溶性ポリシロキサンの各化学式において、〔q（Ｈ・Ｚ）・Ｈ２Ｎ（ＣＨ２）２ＮＨ（ＣＨ２）ｎＳｉＯ１．５〕ｐの構造が備えられていることによって、吸水特性に優れた吸水剤を提供することができる。 That is, in each chemical formula of the water-soluble polysiloxane, a structure of [q (H · Z) · H 2 N (CH 2 ) 2 NH (CH 2 ) n SiO 1.5 ] p is provided. A water-absorbing agent having excellent water-absorbing properties can be provided.
　また、本発明に係る吸水剤では、吸水剤１００質量部に対する固形分が、７０質量部以上であることが好ましい。 In the water-absorbing agent according to the present invention, the solid content with respect to 100 parts by mass of the water-absorbing agent is preferably 70 parts by mass or more.
　固形分が上記範囲よりも少なくなってしまうと、流動性が悪くなり製造し支障をきたすばかりか、吸水性樹脂が粉砕できなくなるおそれ、また、特定の粒度分布に制御できなくなってしまうおそれがある。 If the solid content is less than the above range, not only the fluidity is deteriorated and the production may be hindered, but the water absorbent resin may not be pulverized and may not be controlled to a specific particle size distribution. .
　また、本発明に係る吸収性物品は、酸基含有不飽和単量体１００質量部に対し、上記水溶性ポリシロキサンを０．００１質量部以上、１０質量部以下用いることによって得られたことが好ましい。 The absorbent article according to the present invention is obtained by using 0.001 part by mass or more and 10 parts by mass or less of the water-soluble polysiloxane with respect to 100 parts by mass of the acid group-containing unsaturated monomer. preferable.
　上記使用量が上記範囲である場合には、吸水剤の十分な吸収特性が得られないおそれを回避できる。 When the amount used is within the above range, it is possible to avoid the possibility that sufficient absorption characteristics of the water absorbing agent cannot be obtained.
　また、本発明に係る吸収性物品は、上記吸水剤を含むものである。 Moreover, the absorbent article according to the present invention contains the above water-absorbing agent.
　上記吸水剤は、上記水溶性ポリシロキサンを含む新規な吸水剤であるので、新たな吸収性物品を提供することができる。 Since the water-absorbing agent is a novel water-absorbing agent containing the water-soluble polysiloxane, a new absorbent article can be provided.
　本発明に係る吸水剤の製造方法は、上記課題を解決するために、酸基含有不飽和単量体を内部架橋剤の存在下において架橋重合することによって得られた含水ゲル状架橋重合体を、乾燥し、吸水剤を得る吸水剤の製造方法において、上記内部架橋剤として、アミノ基を有する水溶性ポリシロキサンを用いることを特徴としている。 In order to solve the above-described problem, the method for producing a water-absorbing agent according to the present invention comprises a hydrogel crosslinked polymer obtained by crosslinking polymerization of an acid group-containing unsaturated monomer in the presence of an internal crosslinking agent. In the method for producing a water absorbent, which is dried to obtain a water absorbent, a water-soluble polysiloxane having an amino group is used as the internal crosslinking agent.
　上記製造方法によれば、内部架橋剤として、上記水溶性ポリシロキサンを用いることによって、吸水性樹脂の内部が水溶性ポリシロキサンで架橋されるため、水溶性ポリシロキサンを含む新規な吸水剤を製造することができる。 According to the above production method, by using the water-soluble polysiloxane as the internal cross-linking agent, the inside of the water-absorbent resin is cross-linked with the water-soluble polysiloxane, and thus a novel water-absorbing agent containing the water-soluble polysiloxane is produced. can do.
　本発明に係る吸水剤の製造方法は、上記課題を解決するために、酸基含有不飽和単量体を内部架橋剤の存在下において架橋重合することによって得られた含水ゲル状架橋重合体を、乾燥し、吸水剤を得る吸水剤の製造方法において、上記含水ゲル状架橋重合体を乾燥し、得られた含水ゲル状架橋重合体乾燥物に、アミノ基を有する水溶性ポリシロキサンを用いて含水ゲル状架橋重合体乾燥物を表面処理することを特徴としている。 In order to solve the above-described problem, the method for producing a water-absorbing agent according to the present invention comprises a hydrogel crosslinked polymer obtained by crosslinking polymerization of an acid group-containing unsaturated monomer in the presence of an internal crosslinking agent. In the method for producing a water-absorbing agent, drying to obtain a water-absorbing agent, the water-containing gel-like crosslinked polymer is dried, and the obtained water-containing gel-like crosslinked polymer dried product is used with a water-soluble polysiloxane having an amino group. It is characterized by surface-treating a dried hydrogel crosslinked polymer.
　上記製造方法によれば、表面処理後の含水ゲル状架橋重合体乾燥物を上記水溶性ポリシロキサンによって、共有結合および／またはイオン結合を介して架橋させることができ、加圧下の通液性が向上された水溶性ポリシロキサンを含む新規な吸水剤を製造することができる。 According to the above production method, the dried hydrogel crosslinked polymer after the surface treatment can be crosslinked with the water-soluble polysiloxane via a covalent bond and / or an ionic bond. A novel water-absorbing agent containing improved water-soluble polysiloxane can be produced.
　本発明に係る吸水剤の製造方法は、上記課題を解決するために、酸基含有不飽和単量体を内部架橋剤の存在下において架橋重合することによって得られた含水ゲル状架橋重合体を、乾燥し、吸水剤を得る吸水剤の製造方法において、上記含水ゲル状架橋重合体を乾燥し、得られた含水ゲル状架橋重合体乾燥物に表面架橋処理を施した後に、さらに、アミノ基を有する水溶性ポリシロキサンを表面架橋処理が施された含水ゲル状架橋重合体乾燥物に添加することを特徴としている。 In order to solve the above-described problem, the method for producing a water-absorbing agent according to the present invention comprises a hydrogel crosslinked polymer obtained by crosslinking polymerization of an acid group-containing unsaturated monomer in the presence of an internal crosslinking agent. In the method for producing a water-absorbing agent, drying to obtain a water-absorbing agent, after drying the water-containing gel-like crosslinked polymer and subjecting the obtained water-containing gel-like crosslinked polymer dried product to surface crosslinking treatment, It is characterized by adding a water-soluble polysiloxane having a water-soluble gel-like crosslinked polymer dried product subjected to a surface crosslinking treatment.
　表面処理剤として、上記水溶性ポリシロキサンを作用させることによって、含水ゲル状架橋重合体乾燥物の表面を水溶性ポリシロキサンで架橋することができ、水溶性ポリシロキサンを含む新規な吸水剤を製造することができる。 The surface of the dried hydrogel crosslinked polymer can be crosslinked with the water-soluble polysiloxane by the action of the water-soluble polysiloxane as the surface treatment agent, and a novel water-absorbing agent containing the water-soluble polysiloxane is produced. can do.
　また、本発明に係る吸水剤の製造方法では、上記水溶性ポリシロキサンは、以下の化学式（１）～化学式（４）
　〔ｑ（Ｈｘ・Ｚ）・（Ｒ１）２Ｎ（ＣＨ２）ｎＳｉＯ１．５〕ｐ〔ＣｊＨ２ｊ＋１ＯＳｉＯ１．５〕１－Ｐ・・・化学式（１）
　〔ｑ（Ｈｘ・Ｚ）・（Ｒ１）２Ｎ（ＣＨ２）ｎＳｉＯ１．５〕ｐ〔ＣＨ３（ＣＨ２）ｍＳｉＯ１．５〕１－Ｐ・・・化学式（２）
　〔ｑ（Ｈｘ・Ｚ）・（Ｒ１）２Ｎ（ＣＨ２）ｎＳｉＯ１．５〕ｐ〔Ｒ２ＳｉＯ１．５〕１－Ｐ・・・化学式（３）
　〔ｑ（Ｈｘ・Ｚ）・（Ｒ１）２Ｎ（ＣＨ２）ｎＳｉＯ１．５〕ｐ〔Ｒ３ＮＨ（ＣＨ２）ｎＳｉＯ１．５〕１－Ｐ・・・化学式（４）
（上記化学式（１）～化学式（４）において、それぞれ独立して、ｎは１以上、６以下の何れかの整数であり、ｊは０以上、４以下の何れかの整数であり、ｍは０以上、４以下の何れかの整数であり、ｐはそれぞれ独立して、０を越え、１以下の範囲の値であり、Ｒ１はそれぞれ独立して、水素原子、アルキル基、置換アルキル基またはアリル基であり、Ｒ２は水素原子、ビニル基またはアリル基であり、Ｒ３は、アクリロイル基またはメタアクリロイル基であり、Ｚは１価もしくは２価の陰イオンであり、ｑは中和率を乗じた値であって、Ｒ１がアミノ基を含む場合、０．１以上２以下の範囲の数であり、Ｒ１がアミノ基を含まない場合、０．１以上１以下の範囲の数であり、ｘはＺが１価の陰イオンの場合１であり、Ｚが２価の陰イオンの場合２である。）
で示される少なくとも何れかの分子構造を有することが好ましい。 In the method for producing a water-absorbing agent according to the present invention, the water-soluble polysiloxane has the following chemical formulas (1) to (4):
[Q (H x · Z) · (R 1 ) 2 N (CH 2 ) n SiO 1.5 ] p [C j H 2j + 1 OSiO 1.5 ] 1-P Chemical formula (1)
[Q (H x · Z) · (R 1) 2 N (CH 2) n SiO 1.5 ] p [CH 3 (CH 2) m SiO 1.5 ] 1-P · · · formula (2)
[Q (H x · Z) · (R 1 ) 2 N (CH 2 ) n SiO 1.5 ] p [R 2 SiO 1.5 ] 1-P ... Chemical formula (3)
[Q (H x · Z) · (R 1 ) 2 N (CH 2 ) n SiO 1.5 ] p [R 3 NH (CH 2 ) n SiO 1.5 ] 1-P ( 1 ) Chemical formula (4)
(In the above chemical formulas (1) to (4), n is independently an integer of 1 or more and 6 or less, j is an integer of 0 or more and 4 or less, and m is Any integer of 0 or more and 4 or less, p is independently a value in the range of more than 0 and 1 or less, and R 1 is independently a hydrogen atom, an alkyl group, or a substituted alkyl group. Or an allyl group, R 2 is a hydrogen atom, a vinyl group or an allyl group, R 3 is an acryloyl group or a methacryloyl group, Z is a monovalent or divalent anion, and q is neutralized When R 1 includes an amino group, the number is in the range of 0.1 to 2, and when R 1 does not include an amino group, the value is in the range of 0.1 to 1 X is 1 when Z is a monovalent anion and Z is a divalent anion In the case of emissions is 2.)
It preferably has at least one molecular structure represented by
　上記水溶性ポリシロキサンが上記化学式（１）～化学式（４）で示される少なくとも何れかの分子構造を有する場合、上記水溶性ポリシロキサンを合成することが簡便となり、上記吸水剤をより簡便に製造することができる。 When the water-soluble polysiloxane has at least one of the molecular structures represented by the chemical formulas (1) to (4), it is easy to synthesize the water-soluble polysiloxane, and the water-absorbing agent is more easily produced. can do.
　本発明の他の目的、特徴、および優れた点は、以下に示す記載によって十分分かるであろう。また、本発明の利点は、添付図面を参照した次の説明によって明白になるであろう。 Other objects, features, and superior points of the present invention will be fully understood from the following description. The advantages of the present invention will become apparent from the following description with reference to the accompanying drawings.
本実施例に係るＳＦＣの測定装置を示す概略図である。It is the schematic which shows the measuring apparatus of SFC which concerns on a present Example. 加圧下吸収倍率（ＡＡＰ）の測定に用いる測定装置の概略の断面図である。It is general | schematic sectional drawing of the measuring apparatus used for a measurement of absorption magnification under pressure (AAP).
符号の説明Explanation of symbols
　１０　測定装置
　２０　測定装置
　２１　タンク
　２２　ガラス管
　２３　０．６９質量％食塩水
　２４　コック付きＬ字管
　２５　コック　
　３０　容器
　３１　セル
　３２　ステンレス製金網
　３３　金網
　３４　ゲル（吸水剤）
　３５　ガラスフィルター
　３６　ピストン
　３７　穴
　３８　捕集容器
　３９　上皿天秤
　１００　支持円筒
　１０１　金網
　１０２　吸水性樹脂
　１０３　ピストン
　１０４　荷重
　１０５　ペトリ皿
　１０６　ガラスフィルター
　１０７　濾紙
　１０８　生理食塩水 DESCRIPTION OF SYMBOLS 10 Measuring apparatus 20 Measuring apparatus 21 Tank 22 Glass tube 23 0.69 mass% salt solution 24 L-shaped pipe with cock 25 Cock
30 container 31 cell 32 stainless steel wire mesh 33 wire mesh 34 gel (water absorbing agent)
35 Glass filter 36 Piston 37 Hole 38 Collection container 39 Upper plate balance 100 Support cylinder 101 Wire net 102 Water absorbent resin 103 Piston 104 Load 105 Petri dish 106 Glass filter 107 Filter paper 108 Saline
　以下、本発明について詳しく説明するが、本発明の範囲はこれらの説明に拘束されることはなく、以下の例示以外についても、本発明の趣旨を損なわない範囲で適宜変更して実施し得るものである。 Hereinafter, the present invention will be described in detail. However, the scope of the present invention is not limited to these descriptions, and other than the following examples, the present invention can be appropriately modified and implemented without departing from the spirit of the present invention. It is.
　本発明に係る吸水剤は、酸基含有不飽和単量体由来の構成単位を有する吸水性樹脂と、解離基を有する水溶性ポリシロキサンとを含むものである。上記吸水性樹脂は、ポリシロキサンによって架橋されているものである。吸水性樹脂はその表面またはその内部のうち少なくとも何れかが架橋されていればよい。以下、本発明に係る吸水剤を得るために用いられる各化合物および吸水剤について説明する。また、以下、本発明に係る水溶性ポリシロキサンを、単にポリシロキサンと表記する場合がある。 The water-absorbing agent according to the present invention contains a water-absorbing resin having a structural unit derived from an acid group-containing unsaturated monomer and a water-soluble polysiloxane having a dissociating group. The water absorbent resin is crosslinked with polysiloxane. It is sufficient that at least one of the surface or the inside of the water absorbent resin is crosslinked. Hereinafter, each compound and water absorbing agent used for obtaining the water absorbing agent according to the present invention will be described. Hereinafter, the water-soluble polysiloxane according to the present invention may be simply referred to as polysiloxane.
　なお、以下の説明において、「重量」は「質量」と同義語として扱い、「重量％」は「質量％」と同義語として扱う。 In the following description, “weight” is treated as a synonym for “mass”, and “weight%” is treated as a synonym for “mass%”.
　（１）吸水性樹脂
　本発明では、吸水性樹脂として、酸基含有不飽和単量体を架橋重合した吸水性樹脂および後述の水溶性ポリシロキサンが必須に用いられる。この吸水性樹脂は、架橋重合した構造である吸水性樹脂であればよく、酸基および／またはその塩含有不飽和単量体を重合後に、架橋剤ないし重合時の自己架橋により架橋反応して得られる吸水性樹脂でもよい。 (1) Water-absorbing resin In the present invention, as the water-absorbing resin, a water-absorbing resin obtained by crosslinking and polymerizing an acid group-containing unsaturated monomer and a water-soluble polysiloxane described later are essential. The water-absorbing resin may be a water-absorbing resin having a cross-linked polymerization structure, and after the acid group and / or its salt-containing unsaturated monomer is polymerized, it undergoes a cross-linking reaction by self-crosslinking during polymerization or polymerization. The obtained water-absorbent resin may be used.
　上記吸水性樹脂は、酸基含有不飽和単量体由来の構成単位を有し、好ましくは、上記構成単位を主成分として有している。「主成分として有している」とは、吸水性樹脂の全質量に対し、９０％以上含んでいることを示す。また、上記「酸基含有不飽和単量体由来の構成単位」とは、例えば、重合反応によって、酸基含有不飽和単量体の重合に関与する２重結合部分が単結合となった酸基含有不飽和単量体の構造を示すこととする。 The water-absorbent resin has a structural unit derived from an acid group-containing unsaturated monomer, and preferably has the structural unit as a main component. “Having as a main component” means containing 90% or more of the total mass of the water-absorbent resin. The above-mentioned “structural unit derived from an acid group-containing unsaturated monomer” means, for example, an acid in which a double bond part involved in polymerization of an acid group-containing unsaturated monomer is converted to a single bond by a polymerization reaction. The structure of the group-containing unsaturated monomer will be shown.
　本発明に係る吸水性樹脂とは、ヒドロゲルを形成しうる水膨潤性、水不溶性の架橋重合体のことである。ここで、水膨潤性の吸水性樹脂とは、イオン交換水中において必須に自重の５倍以上、好ましくは５０倍から１０００倍という多量の水を吸収するものを指す。また、水不溶性の吸水性樹脂とは、吸水性樹脂中の未架橋の水可溶性成分（水溶性高分子）が好ましくは５０質量％以下（下限０％）、より好ましくは２５質量％以下、さらに好ましくは２０質量％以下、特に好ましくは１５質量％以下、最も好ましくは１０質量％以下のものを指す。 The water-absorbent resin according to the present invention is a water-swellable and water-insoluble crosslinked polymer capable of forming a hydrogel. Here, the water-swellable water-absorbing resin refers to one that absorbs a large amount of water in ion-exchanged water essentially 5 times or more of its own weight, preferably 50 to 1000 times. The water-insoluble water-absorbent resin is preferably an uncrosslinked water-soluble component (water-soluble polymer) in the water-absorbent resin, preferably 50% by mass or less (lower limit 0%), more preferably 25% by mass or less. It is preferably 20% by mass or less, particularly preferably 15% by mass or less, and most preferably 10% by mass or less.
　また、上記架橋重合体とは、良好な吸収特性を得るために、不飽和単量体を重合することによって得られる重合体の内部に架橋構造（以下、「内部架橋構造」という）を有する重合体をいう。 The above-mentioned crosslinked polymer is a polymer having a crosslinked structure (hereinafter referred to as “internal crosslinked structure”) inside a polymer obtained by polymerizing an unsaturated monomer in order to obtain good absorption characteristics. Refers to coalescence.
　上記吸水性樹脂は酸基含有不飽和単量体由来の構成単位を有しており、一方、後に詳述するが、水溶性ポリシロキサンは、解離基を有している。上記解離基とは、プロトン受容基およびプロトン供与基の両方を含むものである。具体的には、アミノ基、カルボキシル基、スルホン酸基、硫酸エステル基、リン酸基などを挙げることができ、好ましくはアミノ基を挙げることができる。 The water-absorbent resin has a structural unit derived from an acid group-containing unsaturated monomer. On the other hand, as will be described in detail later, the water-soluble polysiloxane has a dissociating group. The dissociating group includes both a proton accepting group and a proton donating group. Specific examples include an amino group, a carboxyl group, a sulfonic acid group, a sulfate ester group, and a phosphoric acid group, and an amino group is preferable.
　上記吸水性樹脂は、カルボキシル基を含有した不飽和単量体を重合してなる場合、本発明に係る水溶性ポリシロキサンは解離基としてアミノ基を有することが好ましい。これにより、カルボン酸を有する吸水性樹脂であれば、上記水溶性ポリシロキサンのアミノ基と吸水性樹脂のカルボキシル基とが、化学結合（共有結合、イオン結合）することで、吸水性樹脂内部および／または表面を架橋することができる。 When the water-absorbing resin is formed by polymerizing an unsaturated monomer containing a carboxyl group, the water-soluble polysiloxane according to the present invention preferably has an amino group as a dissociating group. Thereby, if it is a water absorbing resin which has carboxylic acid, the amino group of the said water-soluble polysiloxane and the carboxyl group of a water absorbing resin will carry out a chemical bond (covalent bond, ionic bond), and inside a water absorbing resin and / Or the surface can be cross-linked.
　さらに、上記吸水性樹脂は、該吸水性樹脂表面に架橋構造を形成する表面架橋処理が施されていてもよく、該表面架橋処理が施されていなくてもよい。このうち、優れた吸収特性を得るためには、表面架橋処理が施されていることが好ましい。 Furthermore, the water-absorbent resin may be subjected to a surface cross-linking treatment that forms a cross-linked structure on the surface of the water-absorbent resin, or may not be subjected to the surface cross-linking treatment. Among these, in order to obtain excellent absorption characteristics, it is preferable that a surface crosslinking treatment is performed.
　上記の架橋重合体からなる吸水性樹脂としては、例えば、ポリアクリル酸部分中和物重合体、デンプン－アクリロニトリルグラフト重合体の加水分解物、デンプン－アクリル酸グラフト重合体またはその中和物、カルボキシメチルセルロース架橋体、酢酸ビニル－アクリル酸エステル共重合体のケン化物、アクリロニトリル共重合体若しくはアクリルアミド共重合体の加水分解物またはこれらの架橋体、カルボキシル基含有架橋ポリビニルアルコール変性物、カチオン性モノマーの架橋体、２－アクリルアミド－２－メチルプロパンスルホン酸とアクリル酸の架橋体、架橋イソブチレン－（無水）マレイン酸共重合体等の１種または２種以上を挙げることができる。その中でも、アクリル酸および／またはその塩（中和物）を主成分とする不飽和単量体を重合および架橋することにより得られるポリアクリル酸部分中和物重合体を用いることがさらに好ましい。 Examples of the water-absorbing resin comprising the above-mentioned crosslinked polymer include polyacrylic acid partially neutralized polymer, starch-acrylonitrile graft polymer hydrolyzate, starch-acrylic acid graft polymer or neutralized product thereof, carboxy Cross-linked methylcellulose, saponified product of vinyl acetate-acrylic ester copolymer, hydrolyzate of acrylonitrile copolymer or acrylamide copolymer or cross-linked product thereof, carboxyl group-containing cross-linked polyvinyl alcohol modified product, cross-linked cationic monomer 1 type or 2 types or more, such as a crosslinked product of 2-acrylamido-2-methylpropanesulfonic acid and acrylic acid, and a crosslinked isobutylene- (maleic anhydride) copolymer. Among them, it is more preferable to use a polyacrylic acid partial neutralized polymer obtained by polymerizing and crosslinking an unsaturated monomer mainly composed of acrylic acid and / or a salt thereof (neutralized product).
　上記の架橋重合体からなる吸水性樹脂は、不飽和単量体を重合・架橋することによって得られ、必要に応じて表面架橋処理が施される。以下、吸水性樹脂の製造に用いられる水溶性ポリシロキサン、不飽和単量体、架橋性単量体（内部架橋剤）、重合開始剤、表面架橋剤等について説明する。 The water-absorbing resin composed of the above-mentioned crosslinked polymer is obtained by polymerizing and crosslinking an unsaturated monomer, and is subjected to surface crosslinking treatment as necessary. Hereinafter, the water-soluble polysiloxane, unsaturated monomer, crosslinkable monomer (internal crosslinker), polymerization initiator, surface crosslinker and the like used for the production of the water absorbent resin will be described.
　（２）水溶性ポリシロキサン
　本発明に係る水溶性ポリシロキサンについて以下に説明する。上記水溶性ポリシロキサンは、解離基を有する水溶性ポリシロキサンである。上記水溶性ポリシロキサンが解離基、好ましくはアミノ基を有していることによって、水溶性が示され、吸水性樹脂との反応によって、吸水剤を提供することが可能となる。また、吸水剤にポリシロキサン構造を含めることができるため、新たな吸水剤の設計が可能となる。 (2) Water-soluble polysiloxane The water-soluble polysiloxane according to the present invention will be described below. The water-soluble polysiloxane is a water-soluble polysiloxane having a dissociation group. When the water-soluble polysiloxane has a dissociation group, preferably an amino group, water-solubility is exhibited, and a water-absorbing agent can be provided by reaction with a water-absorbing resin. Further, since the water-absorbing agent can include a polysiloxane structure, a new water-absorbing agent can be designed.
　また、上記ポリシロキサンは、一般的なポリシロキサンが有しない解離基、好ましくはアミノ基を分子構造中に有している。このため、本発明に係るポリシロキサンは、水溶性を示すことができ、水溶液または極性の高い溶媒に溶解させ用いることができる。水溶性とは、１００ｇの純水に０．１ｇ以上、好ましくは１ｇ以上溶解し透明で均一な溶液を与えることである。さらに、吸水性樹脂の原料である酸基含有不飽和単量体が有するカルボキシル基に対し、共有結合および／またはイオン結合を介して結合することができる。 Further, the polysiloxane has a dissociation group, preferably an amino group, which the general polysiloxane does not have in the molecular structure. Therefore, the polysiloxane according to the present invention can exhibit water solubility, and can be used by dissolving in an aqueous solution or a highly polar solvent. Water solubility means that a solution of 0.1 g or more, preferably 1 g or more, is dissolved in 100 g of pure water to give a transparent and uniform solution. Furthermore, it can couple | bond with the carboxyl group which the acid group containing unsaturated monomer which is a raw material of a water absorbing resin has through a covalent bond and / or an ionic bond.
　具体的な用途として、後述する不飽和単量体を重合する際に、架橋性単量体として用いることができる。また、他の用途として、吸水性樹脂を得た後に、吸水性樹脂を表面架橋するための表面処理剤として用いることもできる。表面処理剤として、表面架橋された吸水性樹脂の表面にポリシロキサンを作用させることによって、吸水性樹脂の表面を共有結合および／またはイオン結合を介して表面架橋することも可能である。このように、上記ポリシロキサンを吸水性樹脂に対し、種々の手法によって作用させることによって、従来にない構造の吸水剤を得ることができるのである。 As a specific use, it can be used as a crosslinkable monomer when an unsaturated monomer described later is polymerized. Moreover, as another use, after obtaining a water absorbing resin, it can also be used as a surface treating agent for surface cross-linking of the water absorbing resin. As the surface treatment agent, the surface of the water-absorbent resin can be cross-linked through covalent bonds and / or ionic bonds by allowing polysiloxane to act on the surface of the surface-crosslinked water-absorbent resin. Thus, by making the polysiloxane act on the water-absorbent resin by various techniques, a water-absorbing agent having an unprecedented structure can be obtained.
　上記水溶性ポリシロキサンとしては特に限定されるものではないが、解離基、好ましくはアミノ基を有しており、水溶性であることが必須とされる。以下、水溶性ポリシロキサンについてより詳細に説明する。なお、水溶性ポリシロキサンとしては、アミノ基を有する分子構造を中心に説明するが、本発明のポリシロキサンは、解離基を有していればよく、アミノ基の部分を上述した解離基に置き換えて構成することができる。 The water-soluble polysiloxane is not particularly limited, but has a dissociation group, preferably an amino group, and is essential to be water-soluble. Hereinafter, the water-soluble polysiloxane will be described in more detail. The water-soluble polysiloxane will be described mainly with respect to a molecular structure having an amino group. However, the polysiloxane of the present invention only needs to have a dissociating group, and the amino group portion is replaced with the dissociating group described above. Can be configured.
　本発明に係る水溶性ポリシロキサンは、その分子構造として、以下の化学式（１）～化学式（４）
　〔ｑ（Ｈｘ・Ｚ）・（Ｒ１）２Ｎ（ＣＨ２）ｎＳｉＯ１．５〕ｐ〔ＣｊＨ２ｊ＋１ＯＳｉＯ１．５〕１－Ｐ・・・化学式（１）
　〔ｑ（Ｈｘ・Ｚ）・（Ｒ１）２Ｎ（ＣＨ２）ｎＳｉＯ１．５〕ｐ〔ＣＨ３（ＣＨ２）ｍＳｉＯ１．５〕１－Ｐ・・・化学式（２）
　〔ｑ（Ｈｘ・Ｚ）・（Ｒ１）２Ｎ（ＣＨ２）ｎＳｉＯ１．５〕ｐ〔Ｒ２ＳｉＯ１．５〕１－Ｐ・・・化学式（３）
　〔ｑ（Ｈｘ・Ｚ）・（Ｒ１）２Ｎ（ＣＨ２）ｎＳｉＯ１．５〕ｐ〔Ｒ３ＮＨ（ＣＨ２）ｎＳｉＯ１．５〕１－Ｐ・・・化学式（４）
（上記化学式（１）～化学式（４）において、それぞれ独立して、ｎは１以上、６以下の何れかの整数であり、ｊは０以上、４以下の何れかの整数であり、ｍは０以上、４以下の何れかの整数であり、ｐはそれぞれ独立して、０を越え、１以下の範囲の値であり、Ｒ１はそれぞれ独立して、水素原子、アルキル基、置換アルキル基またはアリル基であり、Ｒ２は水素原子、ビニル基またはアリル基であり、Ｒ３は、アクリロイル基またはメタアクリロイル基であり、Ｚは１価もしくは２価の陰イオンであり、ｑは中和率を乗じた値であって、Ｒ１がアミノ基を含む場合、０．１以上２以下の範囲の数であり、Ｒ１がアミノ基を含まない場合、０．１以上１以下の範囲の数であり、ｘはＺが１価の陰イオンの場合１であり、Ｚが２価の陰イオンの場合２である。）で示される少なくとも何れかの分子構造を有することが好ましい。 The water-soluble polysiloxane according to the present invention has the following chemical formula (1) to chemical formula (4) as its molecular structure.
[Q (H x · Z) · (R 1 ) 2 N (CH 2 ) n SiO 1.5 ] p [C j H 2j + 1 OSiO 1.5 ] 1-P Chemical formula (1)
[Q (H x · Z) · (R 1) 2 N (CH 2) n SiO 1.5 ] p [CH 3 (CH 2) m SiO 1.5 ] 1-P · · · formula (2)
[Q (H x · Z) · (R 1 ) 2 N (CH 2 ) n SiO 1.5 ] p [R 2 SiO 1.5 ] 1-P ... Chemical formula (3)
[Q (H x · Z) · (R 1 ) 2 N (CH 2 ) n SiO 1.5 ] p [R 3 NH (CH 2 ) n SiO 1.5 ] 1-P ( 1 ) Chemical formula (4)
(In the above chemical formulas (1) to (4), n is independently an integer of 1 or more and 6 or less, j is an integer of 0 or more and 4 or less, and m is Any integer of 0 or more and 4 or less, p is independently a value in the range of more than 0 and 1 or less, and R 1 is independently a hydrogen atom, an alkyl group, or a substituted alkyl group. Or an allyl group, R 2 is a hydrogen atom, a vinyl group or an allyl group, R 3 is an acryloyl group or a methacryloyl group, Z is a monovalent or divalent anion, and q is neutralized When R 1 includes an amino group, the number is in the range of 0.1 to 2, and when R 1 does not include an amino group, the value is in the range of 0.1 to 1 X is 1 when Z is a monovalent anion and Z is a divalent anion For emission is 2.) Preferably has at least one of the molecular structure represented by.
　上記のような分子構造である水溶性ポリシロキサンは、比較的簡便に合成され得る。このため、上記水溶性ポリシロキサンを含む吸水剤をより簡便に製造することが可能となる。 The water-soluble polysiloxane having the molecular structure as described above can be synthesized relatively easily. For this reason, it becomes possible to manufacture the water absorbing agent containing the said water-soluble polysiloxane more simply.
　上記水溶性ポリシロキサンにおいて、ｎ、ｊおよびｍが上記の範囲、すなわち、長鎖アルキル基を有しないことによって、上記ポリシロキサンの疎水性が向上し難い構造となっている。 In the water-soluble polysiloxane, n, j, and m are in the above-mentioned range, that is, the structure has a structure in which the hydrophobicity of the polysiloxane is difficult to improve.
　上記化学式（１）～化学式（４）における繰り返し単位の各割合を示すｐは、０．３以上、１以下であることが好ましく、０．５以上、１以下であることがさらに好ましく、０．９以上、１以下であることが特に好ましい。ｐの値が大きくなるにつれ、ポリシロキサンの水溶性が向上するため、特に水または親水性溶媒に溶解させ易くなる結果、これらの溶媒とより均一な混合をさせることが可能となる。これにより、ポリシロキサンを吸水剤の原料として用いる際に、溶液の状態にて効率良く反応に用いることができ、容易に吸水剤を得ることが可能となる。 P representing the proportion of each repeating unit in the above chemical formulas (1) to (4) is preferably 0.3 or more and 1 or less, more preferably 0.5 or more and 1 or less. It is particularly preferably 9 or more and 1 or less. As the value of p increases, the water-solubility of the polysiloxane improves, so that it is particularly easy to dissolve in water or a hydrophilic solvent, so that more uniform mixing with these solvents can be achieved. Thus, when polysiloxane is used as a raw material for the water-absorbing agent, it can be efficiently used in the reaction in a solution state, and the water-absorbing agent can be easily obtained.
　上記化学式（１）～化学式（４）において、Ｒ１は、それぞれ独立して、水素原子、アルキル基またはアリル基である。 In the chemical formulas (1) to (4), each R 1 is independently a hydrogen atom, an alkyl group, or an allyl group.
　アルキル基としては、無置換であってもよく、アミノ基、エポキシ基または不飽和基の何れかを含む置換基が導入されていてもよい。置換基が導入されたアルキル基を置換アルキル基と称する。なお、不飽和基とは、二重結合または三重結合を含む分子構造を示す。 The alkyl group may be unsubstituted, or a substituent containing any of an amino group, an epoxy group or an unsaturated group may be introduced. An alkyl group into which a substituent is introduced is referred to as a substituted alkyl group. In addition, an unsaturated group shows the molecular structure containing a double bond or a triple bond.
　上記アルキル基としては、具体的には、直鎖状のアルキル基として、メチル基、エチル基、プロピル基、ブチル基、ペンチル基、ヘキシル基、ヘプチル基、オクチル基、ノニル基、デシル基、ウンデシル基、ドデシル基などが挙げられる。 Specific examples of the alkyl group include a linear alkyl group such as methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, and undecyl. Group, dodecyl group and the like.
　アリル基としては、２－プロペニル基を含んでいれば特に限定されるものではなく、（２－プロペニル）メチル基、（２－プロペニル）エチル基、（２－プロペニル）プロピル基、（２－プロペニル）ブチル基、（２－プロペニル）ペンチル基、（２－プロペニル）ヘキシル基、（２－プロペニル）ヘプチル基、（２－プロペニル）オクチル基、（２－プロペニル）ノニル基、（２－プロペニル）デシル基、（２－プロペニル）ウンデシル基、（２－プロペニル）ドデシル基などが挙げられる。 The allyl group is not particularly limited as long as it contains a 2-propenyl group. (2-propenyl) methyl group, (2-propenyl) ethyl group, (2-propenyl) propyl group, (2-propenyl) ) Butyl group, (2-propenyl) pentyl group, (2-propenyl) hexyl group, (2-propenyl) heptyl group, (2-propenyl) octyl group, (2-propenyl) nonyl group, (2-propenyl) decyl Group, (2-propenyl) undecyl group, (2-propenyl) dodecyl group and the like.
　上記アルキル基およびアリル基は、アミノ基、エポキシ基または不飽和基の何れかを含む置換基によって置換されていてもよいが、その置換位置は特に限定されるものではない。 The alkyl group and allyl group may be substituted with a substituent containing any of an amino group, an epoxy group, or an unsaturated group, but the substitution position is not particularly limited.
　例えば、アルキル基がアミノ基によって置換された構造としては、アミノメチル基、アミノメチル基、アミノプロピル基、アミノブチル基、アミノペンチル基、アミノヘキシル基、アミノヘプチル基、アミノオクチル基、アミノノニル基、アミノデシル基、アミノウンデシル基、アミノドデシル基、およびこれらの異性体が挙げられる。また、Ｒ１が全て水素原子であり、ｎが３である３－アミノプロピル基であれば、原料の入手が容易であるため、より好ましい。 For example, the structure in which an alkyl group is substituted with an amino group includes an aminomethyl group, an aminomethyl group, an aminopropyl group, an aminobutyl group, an aminopentyl group, an aminohexyl group, an aminoheptyl group, an aminooctyl group, an aminononyl group, Examples include aminodecyl group, aminoundecyl group, aminododecyl group, and isomers thereof. A 3-aminopropyl group in which R 1 is all hydrogen atoms and n is 3 is more preferable because the raw materials are easily available.
　化学式（３）におけるＲ２は、水素原子、ビニル基またはアリル基である。アリル基としては、上記Ｒ１におけるアリル基と同じアリル基である。 R 2 in the chemical formula (3) is a hydrogen atom, a vinyl group or an allyl group. The allyl group is the same allyl group as the allyl group in R 1 described above.
　化学式（１）～化学式（４）において、Ｚは、一価または二価の陰イオンであり、ｑは中和率を乗じた値であって、Ｒ１がアミノ基を含む場合、０．１以上２以下の範囲の数であり、Ｒ１がアミノ基を含まない場合、０．１以上１以下の範囲の数である。 In the chemical formulas (1) to (4), Z is a monovalent or divalent anion, q is a value obtained by multiplying the neutralization rate, and when R 1 contains an amino group, 0.1 The number is in the range of 2 or less and when R 1 does not contain an amino group, the number is in the range of 0.1 or more and 1 or less.
　具体的に説明すると、Ｒ１がアミノ基を含む場合には、Ｒ１がアミノ基を含まない場合よりも、Ｚが窒素上に配位する数が２倍となり得る。Ｒ１がアミノ基を含まない場合には、化学式（１）～化学式（４）において、それぞれ窒素は１原子分含まれているため、中和率は０．１以上１以下の範囲の数であり、ｑも０．１以上１以下の範囲の数となる。一方、Ｒ１がアミノ基を含む場合には、Ｒ１に含まれる窒素にもＺが１または２原子配位することが可能であり、０．１以上１以下の範囲の数である中和率に２倍の数を乗じ、ｑの最大値は２以下となる。つまり、ｑは、０．１以上２以下の範囲の数となる。 Specifically, when R 1 includes an amino group, the number of Z coordinated on nitrogen can be doubled compared to when R 1 does not include an amino group. In the case where R 1 does not contain an amino group, in each of chemical formulas (1) to (4), each nitrogen contains one atom, so the neutralization rate is a number in the range of 0.1 to 1 Yes, q is also a number in the range of 0.1 to 1. On the other hand, when R 1 contains an amino group, Z can be coordinated to 1 or 2 atoms in the nitrogen contained in R 1 , and neutralization is a number in the range of 0.1 to 1 Multiply the rate by a factor of 2, and the maximum value of q is 2 or less. That is, q is a number in the range from 0.1 to 2.
　なお、上記化学式（１）～化学式（４）においては、ｑ－１の割合で、アンモニウム塩となっていない、アミン構造の分子構造が含まれることとなる。 In the chemical formulas (1) to (4), a molecular structure of an amine structure that is not an ammonium salt is included at a ratio of q-1.
　一価または二価の陰イオンとしては、上記水溶性ポリシロキサンを吸水性樹脂に作用させた場合に得られる吸水剤の物性を損なわなければ、特に限定されない。具体的には、塩化物イオン、硝酸イオン、硫酸イオン、カルボキシラートアニオン、ホスホナートアニオンが挙げられる。このうち、カルボキシラートアニオン、ホスホナートアニオンにおいて、アニオン部分に結合している炭化水素の構造としては、炭素数１～１２の炭化水素であり、直鎖構造であっても、側鎖構造を有していてもよい。 The monovalent or divalent anion is not particularly limited as long as the properties of the water-absorbing agent obtained when the water-soluble polysiloxane is allowed to act on the water-absorbing resin are not impaired. Specific examples include chloride ions, nitrate ions, sulfate ions, carboxylate anions, and phosphonate anions. Among these, in the carboxylate anion and phosphonate anion, the structure of the hydrocarbon bonded to the anion moiety is a hydrocarbon having 1 to 12 carbon atoms, and even a straight chain structure has a side chain structure. You may do it.
　化学式（１）～化学式（４）におけるポリシロキサン構造はアミンの構造であってもよい。この場合には、吸水性樹脂とポリシロキサンとは、共有結合および／またはイオン結合を介して結合されることができる。上記ポリシロキサンがアミンの構造である場合、化学式（１）～化学式（４）の構造はそれぞれ、
〔（Ｒ１）２Ｎ（ＣＨ２）ｎＳｉＯ１．５〕ｐ〔ＣｊＨ２ｊ＋１ＯＳｉＯ１．５〕１－Ｐ・・・化学式（１’）
〔（Ｒ１）２Ｎ（ＣＨ２）ｎＳｉＯ１．５〕ｐ〔ＣＨ３（ＣＨ２）ｍＳｉＯ１．５〕１－Ｐ・・・化学式（２’）
〔（Ｒ１）２Ｎ（ＣＨ２）ｎＳｉＯ１．５〕ｐ〔Ｒ２ＳｉＯ１．５〕１－Ｐ・・・化学式（３’）
〔（Ｒ１）２Ｎ（ＣＨ２）ｎＳｉＯ１．５〕ｐ〔Ｒ３ＮＨ（ＣＨ２）ｎＳｉＯ１．５〕１－Ｐ・・・化学式（４’）
と表わすことができる。 The polysiloxane structure in the chemical formulas (1) to (4) may be an amine structure. In this case, the water absorbent resin and the polysiloxane can be bonded via a covalent bond and / or an ionic bond. When the polysiloxane has an amine structure, the structures of the chemical formulas (1) to (4) are respectively
[(R 1 ) 2 N (CH 2 ) n SiO 1.5 ] p [C j H 2j + 1 OSiO 1.5 ] 1-P— Chemical formula (1 ′)
[(R 1 ) 2 N (CH 2 ) n SiO 1.5 ] p [CH 3 (CH 2 ) m SiO 1.5 ] 1-P ... Chemical formula (2 ′)
[(R 1 ) 2 N (CH 2 ) n SiO 1.5 ] p [R 2 SiO 1.5 ] 1-P ... Chemical formula (3 ′)
[(R 1 ) 2 N (CH 2 ) n SiO 1.5 ] p [R 3 NH (CH 2 ) n SiO 1.5 ] 1-P— Chemical formula (4 ′)
Can be expressed as
　上記ポリシロキサンの質量平均分子量としては、特に限定されるものではないが、アンモニウム塩構造の場合、５０００以上、１００００００以下であることが好ましい。質量平均分子量が５０００よりも少ない場合、並びに、１００００００を超える場合には、得られる吸水剤の十分な吸収特性が得られない可能性があるため、好ましくない。 The mass average molecular weight of the polysiloxane is not particularly limited, but in the case of an ammonium salt structure, it is preferably 5000 or more and 1000000 or less. When the mass average molecular weight is less than 5000, and when it exceeds 1000000, there is a possibility that sufficient absorption characteristics of the resulting water-absorbing agent may not be obtained.
　＜ポリシロキサンの製造方法＞
　本発明に係る吸水剤の製造方法について説明する前に、まず、本発明で用いられるポリシロキサンの製造方法を以下に説明する。ポリシロキサンの製造方法は以下の方法に限定されるものではなく、日本国公開特許公報「特開２００５－１２０３３３号」、日本国公開特許公報「特開２００６－４５３９２号」に記載の方法でもよい。本発明にて用いられるポリシロキサンは、少なくとも上述した化学式（１）～化学式（４）の何れかの構造を含んでいる。これら化学式（１）～化学式（４）においては、それぞれ〔ｑ（Ｈｘ・Ｚ）・（Ｒ１）２Ｎ（ＣＨ２）ｎＳｉＯ１．５〕の構造が含まれている。この構造を以下説明の便宜上、基本構造と称する。また、化学式（１）～化学式（４）の基本構造以外の構造部分である、〔ＣｊＨ２ｊ＋１ＯＳｉＯ１．５〕、〔ＣＨ３（ＣＨ２）ｍＳｉＯ１．５〕、〔Ｒ２ＳｉＯ１．５〕および〔Ｒ３ＮＨ（ＣＨ２）ｎＳｉＯ１．５〕の化学構造をそれぞれ、副構造（１）、副構造（２）、副構造（３）および副構造（４）と称する。以下、基本構造、副構造（１）、副構造（２）、副構造（３）および副構造（４）の原料である単量体となる化合物について説明する。 <Method for producing polysiloxane>
Before describing the method for producing a water-absorbing agent according to the present invention, first, the method for producing a polysiloxane used in the present invention will be described below. The method for producing polysiloxane is not limited to the following method, and may be a method described in Japanese Patent Publication “JP-A-2005-120333” or Japanese Patent Publication “JP-A-2006-45392”. . The polysiloxane used in the present invention includes at least one of the structures represented by the chemical formulas (1) to (4). These chemical formulas (1) to (4) each contain a structure of [q (H x · Z) · (R 1 ) 2 N (CH 2 ) n SiO 1.5 ]. Hereinafter, this structure is referred to as a basic structure for convenience of explanation. Further, [C j H 2j + 1 OSiO 1.5 ], [CH 3 (CH 2 ) m SiO 1.5 ], [R 2 SiO, which are structural parts other than the basic structures of chemical formulas (1) to (4). 1.5 ] and [R 3 NH (CH 2 ) n SiO 1.5 ] are referred to as substructure (1), substructure (2), substructure (3) and substructure (4), respectively. . Hereinafter, the compound that is a monomer that is a raw material of the basic structure, the substructure (1), the substructure (2), the substructure (3), and the substructure (4) will be described.
　基本構造の原料となる化合物として、以下の化学式（５）、
（Ｒ１）２Ｎ（ＣＨ２）ｎＳｉ（ＯＲ４）３・・・化学式（５）
で示されるアミノシラン化合物を用いることができる。アミノシランとしては、化学式（５）におけるｎが１以上、６以下の何れかの整数であり、Ｒ１は＜水溶性ポリシロキサン＞にて上述したＲ１と同一の化学構造である。また、Ｒ４はアルキル基であればよく、特に限定されるものではない。Ｒ４の具体例としては、メチル基、エチル基、プロピル基などが例示される。 As a compound that is a raw material of the basic structure, the following chemical formula (5),
(R 1) 2 N (CH 2) n Si (OR 4) 3 ··· formula (5)
The aminosilane compound shown by these can be used. As aminosilane, n in chemical formula (5) is an integer of 1 or more and 6 or less, and R 1 has the same chemical structure as R 1 described above in <Water-soluble polysiloxane>. R 4 is not particularly limited as long as it is an alkyl group. Specific examples of R 4 include a methyl group, an ethyl group, and a propyl group.
　具体的な化合物の代表的な例示としては、Ｒ１が水素である化合物として、アミノメチルメトキシシラン、アミノメチルエトキシシラン、アミノメチルプロポキシシラン、２-アミノエチルメトキシシラン、２-アミノエチルエトキシシラン、２-アミノエチルプロポキシシラン、３‐アミノプロピルメトキシシラン、３‐アミノプロピルエトキシシラン、３－アミノプロピルプロポキシシランなどが例示される。中でも、３‐アミノプロピルメトキシシラン、３‐アミノプロピルエトキシシラン、３－アミノプロピルプロポキシシランが入手容易なため好ましく用いることができる。もちろん、Ｒ１が、水素原子以外の、上記例示したアルキル基またはアリル基であってもよい。 Specific examples of specific compounds include compounds in which R 1 is hydrogen, aminomethylmethoxysilane, aminomethylethoxysilane, aminomethylpropoxysilane, 2-aminoethylmethoxysilane, 2-aminoethylethoxysilane, Examples include 2-aminoethylpropoxysilane, 3-aminopropylmethoxysilane, 3-aminopropylethoxysilane, 3-aminopropylpropoxysilane, and the like. Among these, 3-aminopropylmethoxysilane, 3-aminopropylethoxysilane, and 3-aminopropylpropoxysilane can be preferably used because they are easily available. Of course, R 1 may be an alkyl group or an allyl group exemplified above other than a hydrogen atom.
　一方のＲ１が水素原子であり、他方のＲ１が２－アミノエチル基を有する化合物の一例として、３－（２－アミノエチルアミノ）プロピルトリメトキシシラン、３－（２－アミノエチルアミノ）プロピルトリエトキシシラン、３－（２－アミノエチルアミノ）プロピルトリプロポキシシランを挙げることができる。Ｒ１にアリル基を導入する場合には、さらに、アクリルクロリドなどの不飽和カルボニル基を有する化合物を用いることによって、アリル基を導入することができる。 Examples of compounds in which one R 1 is a hydrogen atom and the other R 1 has a 2-aminoethyl group include 3- (2-aminoethylamino) propyltrimethoxysilane, 3- (2-aminoethylamino) Mention may be made of propyltriethoxysilane and 3- (2-aminoethylamino) propyltripropoxysilane. When an allyl group is introduced into R 1 , the allyl group can be further introduced by using a compound having an unsaturated carbonyl group such as acrylic chloride.
　副構造（１）の原料となる化合物として、以下の化学式（６）、
ＣｊＨ２ｊ＋１ＯＳｉ（ＯＲ５）３・・・化学式（６）
で示されるテトラアルコキシシランを用いることができる。テトラアルコシキシランとしては、化学式（６）におけるｊが０以上、４以下の何れかの整数である。なお、ＣｊＨ２ｊ＋１の構造と、Ｒ４の構造が同一、即ち、対象の分子構造であることが、反応の容易性の観点から好ましい。 As a compound that is a raw material of the substructure (1), the following chemical formula (6),
C j H 2j + 1 OSi ( OR 5) 3 ··· formula (6)
The tetraalkoxysilane shown by these can be used. As tetraalkoxysilane, j in chemical formula (6) is any integer of 0 or more and 4 or less. Note that the structure of C j H 2j + 1, the structure of R 4 are the same, i.e., it is the molecular structure of interest from the viewpoint of easiness of reaction.
　Ｒ５の構造は上述した化学式（５）で示される化合物におけるＲ４として例示したアルキル基と同様の構造である。しかしながら、Ｒ４とＲ５とは同一である必要はなく、それぞれ独立して異なる構造であってよい。これは、ポリシロキサンを製造する際には、Ｒ４を含む構造については、脱離反応にて最終生成物から除かれるためである。 The structure of R 5 is the same structure as the alkyl group exemplified as R 4 in the compound represented by the above chemical formula (5). However, R 4 and R 5 do not have to be the same, and may have different structures. This is because when polysiloxane is produced, the structure containing R 4 is removed from the final product by an elimination reaction.
　具体的な化合物の代表的な例示としては、テトラメトキシシラン、テトラエトキシシラン、テトラプロポキシシランが挙げられるがこれらに限定されるものではない。 Specific examples of specific compounds include, but are not limited to, tetramethoxysilane, tetraethoxysilane, and tetrapropoxysilane.
　副構造（２）の原料となる化合物として、以下の化学式（７）、
ＣＨ３（ＣＨ２）ｍＳｉ（ＯＲ６）３・・・化学式（７）
で示されるトリアルコキシシランを用いることができる。トリアルコシキシランとしては、化学式（７）におけるｍが０以上、４以下の何れかの整数である。また、Ｒ６の構造は上述した化学式（５）で示される化合物におけるＲ４として例示したアルキル基と同様の構造である。しかしながら、Ｒ４とＲ６とは同一である必要はなく、それぞれ独立して異なる構造であってよい。 As a compound that is a raw material of the substructure (2), the following chemical formula (7),
CH 3 (CH 2) m Si (OR 6) 3 ··· formula (7)
The trialkoxysilane shown by these can be used. As for triacoxysilane, m in chemical formula (7) is any integer of 0 or more and 4 or less. The structure of R 6 is the same as the alkyl group exemplified as R 4 in the compound represented by the above chemical formula (5). However, R 4 and R 6 do not have to be the same, and may have different structures.
　具体的な化合物の代表的な例示としては、メチルトリメトキシシラン、メチルトリエトキシシラン、メチルトリプロポキシシラン、エチルトリメトキシシラン、エチルトリエトキシシラン、エチルトリプロポキシシラン、プロピルトリメトキシシラン、プロピルトリエトキシシラン、プロピルトリプロポキシシラン、ブチルトリメトキシシラン、ブチルトリエトキシシラン、ブチルトリプロポキシシラン、ペンチルトリメトキシシラン、ペンチルトリエトキシシラン、ペンチルトリプロポキシシランが例示される。 Representative examples of specific compounds include methyltrimethoxysilane, methyltriethoxysilane, methyltripropoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, ethyltripropoxysilane, propyltrimethoxysilane, and propyltriethoxy. Examples include silane, propyltripropoxysilane, butyltrimethoxysilane, butyltriethoxysilane, butyltripropoxysilane, pentyltrimethoxysilane, pentyltriethoxysilane, and pentyltripropoxysilane.
　副構造（３）の原料となる化合物として、以下の化学式（８）、
Ｒ２Ｓｉ（ＯＲ７）３・・・化学式（８）
で示されるアリルトリアルコキシシランを用いることができる。アリルトリアルコキシシランにおいて、Ｒ２は水素原子、ビニル基またはアリル基であるが、アリル基としては、化学式（１）～化学式（４）におけるＲ１が有してもよいアリル基と同様である。また、Ｒ７の構造は上述した化学式（５）で示される化合物におけるＲ４として例示したアルキル基と同様の構造である。しかしながら、Ｒ４とＲ７とは同一である必要はなく、それぞれ独立して異なる構造であってよい。 As a compound that is a raw material of the substructure (3), the following chemical formula (8),
R 2 Si (OR 7 ) 3 Chemical formula (8)
The allyl trialkoxysilane shown by these can be used. In the allyltrialkoxysilane, R 2 is a hydrogen atom, a vinyl group or an allyl group, and the allyl group is the same as the allyl group which R 1 in the chemical formulas (1) to (4) may have. . The structure of R 7 is the same structure as the alkyl group exemplified as R 4 in the compound represented by the above chemical formula (5). However, R 4 and R 7 do not have to be the same, and may have different structures.
　具体的な化合物の代表的な例示としては、ビニルトリメトキシシラン、ビニルトリエトキシシラン、ビニルトリプロポキシシラン、（２－プロペニル）メチルトリメトキシシラン、（２－プロペニル）メチルトリエトキシシラン、（２－プロペニル）メチルトリプロポキシシラン、（２－プロペニル）エチルトリメトキシシラン、（２－プロペニル）エチルトリエトキシシラン、（２－プロペニル）エチルトリプロポキシシラン、（２－プロペニル）プロピルトリメトキシシラン、（２－プロペニル）プロピルトリエトキシシラン、（２－プロペニル）プロピルトリプロポキシシランなどが挙げられるが、これらに限定されるものではない。 Representative examples of specific compounds include vinyltrimethoxysilane, vinyltriethoxysilane, vinyltripropoxysilane, (2-propenyl) methyltrimethoxysilane, (2-propenyl) methyltriethoxysilane, (2- (Propenyl) methyltripropoxysilane, (2-propenyl) ethyltrimethoxysilane, (2-propenyl) ethyltriethoxysilane, (2-propenyl) ethyltripropoxysilane, (2-propenyl) propyltrimethoxysilane, (2- Propenyl) propyltriethoxysilane, (2-propenyl) propyltripropoxysilane, and the like, but are not limited thereto.
　副構造（４）の原料となる化合物としては、副構造（４）を生成できるものであれば特に限定されない。例えば、アミノメチルメトキシシラン、アミノメチルエトキシシラン、アミノメチルプロポキシシラン、２-アミノエチルメトキシシラン、２-アミノエチルエトキシシラン、２-アミノエチルプロポキシシラン、３‐アミノプロピルメトキシシラン、３‐アミノプロピルエトキシシラン、３－アミノプロピルプロポキシシランなどのアミン類、並びに、アクリロイドクロリドなどのアクリル基導入化合物、または、メタアクリロイドクロリドなどのメタアクリル化基導入化合物反応させて副構造（４）を生成することができる。 The compound used as a raw material for the substructure (4) is not particularly limited as long as it can generate the substructure (4). For example, aminomethylmethoxysilane, aminomethylethoxysilane, aminomethylpropoxysilane, 2-aminoethylmethoxysilane, 2-aminoethylethoxysilane, 2-aminoethylpropoxysilane, 3-aminopropylmethoxysilane, 3-aminopropylethoxy Substructure (4) is generated by reacting amines such as silane and 3-aminopropylpropoxysilane, and acrylic group-introducing compounds such as acryloid chloride or methacrylic group-introducing compounds such as methacryloyl chloride. be able to.
　上記基礎構造の原料となる化合物のみを用いた場合には、ｐが１のポリシロキサンを得ることができる。一方、さらに、副構造（１）～副構造（４）の原料となる化合物のうち少なくとも何れかを用いることによって、化学式（１）～化学式（４）において、ｐはそれぞれ独立して、０を越え、１以下の範囲の値であるポリシロキサンを得ることができる。 When only the compound used as the raw material of the basic structure is used, a polysiloxane having p = 1 can be obtained. On the other hand, by using at least one of the compounds that are the raw materials of the substructure (1) to the substructure (4), p in the chemical formulas (1) to (4) is independently 0. A polysiloxane having a value exceeding 1 and not more than 1 can be obtained.
　基本構造、副構造（１）、副構造（２）、副構造（３）および副構造（４）の原料（以下、これらを「ポリシロキサンの原料」と称する）の比率は特に限定されるものではないが、基本構造の原料に対し、ポリシロキサンの原料の比率が増加するにつれ、得られるポロシロキサンの化学式（１）～化学式（４）におけるｐの値が低下し、ポリシロキサンの親水性が低下するため、基本構造の原料の比率が、ポリシロキサンの原料の総量よりも、多量であることが好ましい。 The ratio of the raw materials of the basic structure, substructure (1), substructure (2), substructure (3) and substructure (4) (hereinafter referred to as “polysiloxane raw material”) is particularly limited. However, as the ratio of the raw material of the polysiloxane to the raw material of the basic structure increases, the value of p in the chemical formulas (1) to (4) of the resulting polysiloxane decreases, and the hydrophilicity of the polysiloxane decreases. In order to reduce, it is preferable that the ratio of the raw material of a basic structure is larger than the total amount of the raw material of polysiloxane.
　具体的には、上記ｐの値が、好ましくは０．３以上、１以下、より好ましくは０．５以上、１以下、特に好ましくは０．９以上、１以下となるよう各原料の比率を調整することが好ましい。 Specifically, the ratio of each raw material is set so that the value of p is preferably 0.3 or more and 1 or less, more preferably 0.5 or more and 1 or less, and particularly preferably 0.9 or more and 1 or less. It is preferable to adjust.
　ポリシロキサンを重合させるためには、まず、酸を触媒として存在させた水溶液に上記の原料を酸に滴下する。酸としては、塩酸、硝酸などを用いることができる。 In order to polymerize polysiloxane, first, the above raw materials are dropped into an acid in an aqueous solution in which an acid is present as a catalyst. As the acid, hydrochloric acid, nitric acid and the like can be used.
　また、上記ポリシロキサンの原料の総量と、酸とのモル比を１：１～１：４の範囲内とすることができる。 In addition, the molar ratio of the total amount of the polysiloxane raw material and the acid can be in the range of 1: 1 to 1: 4.
　また、酸を触媒として存在させた水溶液へポリシロキサンの原料を滴下する際の反応温度は室温であればよい。滴下後、ポリシロキサンの原料を重合させる時間は、用いるポリシロキサンの原料の種類によって適宜変化するが、概して１時間～３時間、重合反応を行えばよい。 Also, the reaction temperature when the polysiloxane raw material is dropped into an aqueous solution containing an acid as a catalyst may be room temperature. After the dropping, the time for polymerizing the polysiloxane raw material varies depending on the type of the polysiloxane raw material to be used, but the polymerization reaction may be generally carried out for 1 to 3 hours.
　その後、反応混合物を開放系の５０℃～８０℃程度の温度条件に設置し、反応混合物から水分を蒸発させる。この工程は、従来公知の乾燥機などを用いて行うことができる。 Thereafter, the reaction mixture is placed in an open system at a temperature of about 50 ° C. to 80 ° C. to evaporate water from the reaction mixture. This step can be performed using a conventionally known dryer or the like.
　水分を蒸発後の混合物に含まれるポリシロキサンは、精製された後に吸水剤の原料として用いられてもよいが、吸水剤を製造する工程において問題が生じなければ、精製されることなく用いられてもよい。ポリシロキサンを精製する方法としては、例えば、上記混合物を蒸留水に溶解させ、さらに、有機溶媒を加えることによって溶解度の差を利用して行う方法を挙げることができる。有機溶媒を加えるに従い、ポリシロキサンが沈殿する。この沈殿物をろ別することによって、ポリシロキサンを精製することができる。 The polysiloxane contained in the mixture after evaporation of water may be used as a raw material for the water-absorbing agent after being purified, but if there is no problem in the process of producing the water-absorbing agent, it is used without being purified. Also good. Examples of a method for purifying polysiloxane include a method in which the above mixture is dissolved in distilled water and an organic solvent is added to make use of the difference in solubility. As the organic solvent is added, the polysiloxane precipitates. The polysiloxane can be purified by filtering this precipitate.
　（３）吸水剤の製造方法
　本発明に係る吸水剤の製造方法としては、大別すると、単量体を重合する工程、得られた単量体を重合して得られる重合体、すなわち、含水ゲル状架橋重合体を乾燥する工程、さらに表面架橋する工程に分けられる。本発明に係る製造方法によれば、これらの工程の何れかにおいて、上述した水溶性ポリシロキサンを吸水性樹脂に含ませることによって、水溶性ポリシロキサンを含む吸水性樹脂を製造することができる。 (3) Method for producing water-absorbing agent The method for producing the water-absorbing agent according to the present invention can be broadly classified as follows: a step of polymerizing monomers, a polymer obtained by polymerizing the obtained monomers, that is, water content It is divided into a step of drying the gel-like crosslinked polymer and a step of surface cross-linking. According to the production method of the present invention, in any of these steps, the water-absorbing resin containing the water-soluble polysiloxane can be produced by including the water-soluble polysiloxane described above in the water-absorbing resin.
　水溶性ポリシロキサンをどのような用途で、どのようなタイミングにて添加するかとしては、以下の（i）～（iv）が挙げられる。 The following (i) to (iv) are mentioned as to what use and at what timing the water-soluble polysiloxane is added.
　（ｉ）単量体を重合する工程において、単量体を重合する際の水溶液に内部架橋剤として水溶性ポリシロキサンを添加する工程
（ii）単量体を重合する工程の後に得られた含水ゲル状架橋重合体に添加する工程
（iii）表面架橋処理において、表面架橋剤として水溶性ポリシロキサンを添加する工程
（iv）表面架橋処理後に、表面架橋された吸水性樹脂に、さらに水溶性ポリシロキサンを添加する工程
　吸水剤の製造方法に含まれる、重合工程、乾燥工程、表面処理工程について、以下に説明する。 (I) In the step of polymerizing the monomer, the step of adding a water-soluble polysiloxane as an internal cross-linking agent to the aqueous solution when polymerizing the monomer (ii) The water content obtained after the step of polymerizing the monomer Step (iii) of adding to the gel-like cross-linked polymer In step of surface cross-linking treatment, step of adding water-soluble polysiloxane as a surface cross-linking agent (iv) After the surface cross-linking treatment, the water-absorbing resin cross-linked with the water-soluble polysiloxane Step of adding siloxane A polymerization step, a drying step, and a surface treatment step included in the method for producing a water absorbing agent will be described below.
　（４）酸基含有不飽和単量体
　本発明の吸水剤に含まれる吸水性樹脂を得るために用いられる酸基含有不飽和単量体としては、所望する架橋重合体を得ることができる不飽和単量体を用いればよい。また、不飽和単量体が水溶性である場合には、後述する水溶性ポリシロキサンとの溶液反応を水溶液重合にて円滑に行うことができる。 (4) Acid group-containing unsaturated monomer The acid group-containing unsaturated monomer used to obtain the water-absorbing resin contained in the water-absorbing agent of the present invention is a compound that can obtain a desired crosslinked polymer. A saturated monomer may be used. When the unsaturated monomer is water-soluble, a solution reaction with a water-soluble polysiloxane described later can be smoothly performed by aqueous solution polymerization.
　上記酸基含有不飽和単量体としては、酸型および／またはその塩の分子構造を有している不飽和単量体を用いることができる。酸基としては、カルボキシル基、スルホ基、アミド基、エステル基などを挙げることができる。 As the acid group-containing unsaturated monomer, an unsaturated monomer having an acid form and / or a salt molecular structure thereof can be used. Examples of the acid group include a carboxyl group, a sulfo group, an amide group, and an ester group.
　酸基含有不飽和単量体の具体的な例としては、ビニルスルホン酸、β－アクリロイルオキシプロピオン酸、メタアクリル酸、（無水）マレイン酸、フマール酸、クロトン酸、イタコン酸、ビニルスルホン酸、２－（メタ）アクリルアミド－２－メチルプロパンスルホン酸、（メタ）アクリロキシアルカンスルホン酸等の酸基含有単体及びこれらのアルカリ金属塩、アンモニウム塩、アルキルアミン塩を挙げることができる。 Specific examples of the acid group-containing unsaturated monomer include vinyl sulfonic acid, β-acryloyloxypropionic acid, methacrylic acid, (anhydrous) maleic acid, fumaric acid, crotonic acid, itaconic acid, vinyl sulfonic acid, Examples include acid group-containing simple substances such as 2- (meth) acrylamido-2-methylpropanesulfonic acid and (meth) acryloxyalkanesulfonic acid, and alkali metal salts, ammonium salts and alkylamine salts thereof.
　例えば上記吸水性樹脂が、アクリル酸部分中和物重合体である場合には、酸基含有不飽和単量体として、アクリル酸および／またはその塩（中和物）を主成分として使用すればよく、該アクリル酸および／またはその塩とともに、アクリル酸および／またはその塩以外の他の不飽和単量体を共重合成分として含まれていてもよい。これにより、最終的に得られる吸水性樹脂に対し、吸水特性以外に、抗菌や消臭等の別の特性を付与することができるとともに、吸水性樹脂をより一層安価に得ることができる。なお、アクリル酸および／またはその塩（中和物）を「主成分として」含むとは、全単量体中、アクリル酸および／またはその塩（中和物）を７０％以上、好ましくは８０％以上含んでいることをいう。 For example, when the water-absorbent resin is a polymer of partially neutralized acrylic acid, if acrylic acid and / or a salt thereof (neutralized product) is used as the main component as the acid group-containing unsaturated monomer. In addition to the acrylic acid and / or salt thereof, other unsaturated monomers other than acrylic acid and / or salt thereof may be included as a copolymerization component. Thereby, in addition to the water absorption property, other properties such as antibacterial properties and deodorization can be imparted to the finally obtained water absorbent resin, and the water absorbent resin can be obtained at a lower cost. The phrase “acrylic acid and / or its salt (neutralized product) as“ main component ”includes 70% or more of acrylic acid and / or its salt (neutralized product) in all monomers, preferably 80%. It means to contain more than%.
　上記他の不飽和単量体としては、Ｎ－ビニル－２－ピロリドン、Ｎ－ビニルアセトアミド、（メタ）アクリルアミド、Ｎ－イソプロピル（メタ）アクリルアミド、Ｎ，Ｎ－ジメチル（メタ）アクリルアミド、２－ヒドロキシエチル（メタ）アクリレート、メトキシポリエチレングリコール（メタ）アクリレート、ポリエチレングリコール（メタ）アクリレート、イソブチレン、ラウリル（メタ）アクリレート等の水可溶性または水不溶性の不飽和単量体等を挙げることができる。これら単量体は、１種類のみを用いてもよく、２種類以上を適宜混合して用いてもよい。本発明の酸基含有不飽和単量体としては、上記他の不飽和単量体を共重合成分とするものも含まれる。 Examples of the other unsaturated monomers include N-vinyl-2-pyrrolidone, N-vinylacetamide, (meth) acrylamide, N-isopropyl (meth) acrylamide, N, N-dimethyl (meth) acrylamide, 2-hydroxy Examples thereof include water-soluble or water-insoluble unsaturated monomers such as ethyl (meth) acrylate, methoxypolyethylene glycol (meth) acrylate, polyethylene glycol (meth) acrylate, isobutylene, and lauryl (meth) acrylate. These monomers may use only 1 type and may mix and use 2 or more types suitably. Examples of the acid group-containing unsaturated monomer of the present invention include those having the other unsaturated monomer as a copolymerization component.
　なお、上記酸基含有不飽和単量体および他の不飽和単量体として、カルボキシル基を含有する不飽和単量体を用いる場合には、該酸基含有不飽和単量体の塩として、アルカリ金属塩、アルカリ土類金属塩、アンモニウム塩、好ましくはアルカリ金属塩を用いればよい。その中で、得られる吸水性樹脂の性能、酸基含有不飽和単量体の塩の工業的な入手の容易さ、安全性等の点から、ナトリウム塩やカリウム塩を少なくとも必須に用いることが好ましい。 In addition, when using an unsaturated monomer containing a carboxyl group as the acid group-containing unsaturated monomer and the other unsaturated monomer, as a salt of the acid group-containing unsaturated monomer, Alkali metal salts, alkaline earth metal salts, ammonium salts, preferably alkali metal salts may be used. Among them, sodium salt or potassium salt should be used at least essential from the viewpoint of the performance of the water-absorbing resin obtained, the industrial availability of the salt of the acid group-containing unsaturated monomer, safety, etc. preferable.
　上記アクリル酸（塩）以外の他の不飽和単量体を併用する場合には、吸水性樹脂を得るために用いる全ての不飽和単量体の総モル数に対して、好ましくは０～３０モル％、より好ましくは０～１０モル％、さらに好ましくは０～５モル％の割合で用いる。言い換えれば、吸水性樹脂を得るために用いる全ての不飽和単量体の総モル数に対して、主成分としてのアクリル酸及びその塩のモル数は、好ましくは７０～１００モル％であり、より好ましくは９０～１００モル％であり、さらに好ましくは９５～１００モル％であればよい。 When another unsaturated monomer other than the acrylic acid (salt) is used in combination, it is preferably 0 to 30 with respect to the total number of moles of all unsaturated monomers used to obtain the water-absorbent resin. It is used in a proportion of mol%, more preferably 0 to 10 mol%, still more preferably 0 to 5 mol%. In other words, the number of moles of acrylic acid and its salt as the main component is preferably 70 to 100 mole% with respect to the total number of moles of all unsaturated monomers used to obtain the water-absorbent resin. More preferably, it is 90 to 100 mol%, and further preferably 95 to 100 mol%.
　また、アクリル酸等の酸基含有不飽和単量体は、物性面及びｐＨ面から中性前後が好ましく、酸基が中和されることが好ましい。酸基の中和率（全酸基中の中和された酸基のモル％）は、通常２０～１００モル％、好ましくは３０～９５モル％、より好ましく４０～８０モル％である。酸基の中和は単量体で行ってもよいし、重合体で行ってもよいし、それらを併用してもよい。 Further, the acid group-containing unsaturated monomer such as acrylic acid is preferably about neutral from the viewpoint of physical properties and pH, and the acid group is preferably neutralized. The neutralization rate of acid groups (mol% of neutralized acid groups in all acid groups) is usually 20 to 100 mol%, preferably 30 to 95 mol%, more preferably 40 to 80 mol%. The neutralization of the acid group may be performed with a monomer, a polymer, or a combination thereof.
　（５）内部架橋剤
　本発明の吸水性樹脂は、内部架橋構造を有する架橋重合体である。ここで、吸水性樹脂が水不溶性及び水膨潤性を有していれば、内部架橋構造を有していると考えることができる。そのため、吸水性樹脂の内部架橋構造は、内部架橋剤である架橋単量体を用いずに、不飽和単量体の自己架橋によって得られるものであってもよい。ただし、好ましくは上記の不飽和単量体と架橋単量体とを共重合または反応させて得られるものがよい。ここで、内部架橋剤である架橋単量体とは、一分子中に２個以上の重合性不飽和基や、２個以上の反応性基を有するものである。 (5) Internal cross-linking agent The water-absorbent resin of the present invention is a cross-linked polymer having an internal cross-linked structure. Here, if the water absorbent resin has water insolubility and water swellability, it can be considered to have an internal cross-linked structure. Therefore, the internal cross-linking structure of the water-absorbent resin may be obtained by self-crosslinking of an unsaturated monomer without using a cross-linking monomer that is an internal cross-linking agent. However, those obtained by copolymerizing or reacting the unsaturated monomer and the crosslinking monomer are preferable. Here, the cross-linking monomer as an internal cross-linking agent has two or more polymerizable unsaturated groups or two or more reactive groups in one molecule.
　上記内部架橋剤としては、まず、上述したポリシロキサンを用いることができる。上記ポリシロキサンを内部架橋剤として用いることによって、ポリシロキサンに含まれる解離基の部分によって、不飽和単量体とポリシロキサンとを反応させることができ、得られる吸水性樹脂の内部にポリシロキサン構造を有する吸水剤を提供することができる。 As the internal cross-linking agent, first, the above-described polysiloxane can be used. By using the polysiloxane as an internal cross-linking agent, the unsaturated monomer and the polysiloxane can be reacted by the dissociation group portion contained in the polysiloxane, and the polysiloxane structure is formed inside the resulting water-absorbent resin. It is possible to provide a water-absorbing agent having
　また、ポリシロキサンが不飽和基を含む場合には、解離基による架橋に加えて、単量体と付加重合を生じさせることができるため、架橋方法のバリエーションを増加させることができ、架橋構造の異なる吸水剤を得ることができる。 Further, when the polysiloxane contains an unsaturated group, in addition to crosslinking by a dissociating group, addition polymerization can occur with the monomer, so that variations in the crosslinking method can be increased, and the crosslinking structure can be increased. Different water-absorbing agents can be obtained.
　また、その他の内部架橋剤として、例えば、Ｎ，Ｎ’－メチレンビス（メタ）アクリルアミド、（ポリ）エチレングリコールジ（メタ）アクリレート、（ポリ）プロピレングリコールジ（メタ）アクリレート、トリメチルロールプロパントリ（メタ）アクリレート、グリセリントリ（メタ）アクリレート、グリセリンアクリレートメタクリレート、エチレンオキサイド変性トリメチロールプロパントリ（メタ）アクリレート、ペンタエリスリトールヘキサ（メタ）アクリレート、トリアリルシアヌレート、トリアリルイソシアヌレート、トリアリルホスフェート、トリアリルアミン、ポリ（メタ）アリロキシアルカン、（ポリ）エチレングリコールジグリシジルエーテル、グリセロールジグリシジルエーテル、エチレングリコール、ポリエチレングリコール、プロピレングリコール、グリセリン、ペンタエリスリトール、エチレンジアミン、エチレンカーボネート、プロピレンカーボネート、ポリエチレンイミン、グリシジル（メタ）アクリレート等を挙げることができる。 Other internal crosslinking agents include, for example, N, N′-methylenebis (meth) acrylamide, (poly) ethylene glycol di (meth) acrylate, (poly) propylene glycol di (meth) acrylate, trimethylolpropane tri (meta) ) Acrylate, glycerin tri (meth) acrylate, glycerin acrylate methacrylate, ethylene oxide modified trimethylolpropane tri (meth) acrylate, pentaerythritol hexa (meth) acrylate, triallyl cyanurate, triallyl isocyanurate, triallyl phosphate, triallylamine , Poly (meth) allyloxyalkane, (poly) ethylene glycol diglycidyl ether, glycerol diglycidyl ether, ethylene glycol, polyethylene Glycol, propylene glycol, glycerol, pentaerythritol, ethylenediamine, ethylene carbonate, propylene carbonate, polyethylenimine, and glycidyl (meth) acrylate.
　上記内部架橋剤は、単独で用いてもよく、適宜２種類以上を混合して用いてもよい。また、上記内部架橋剤は、反応系に一括して添加してもよく、分割して添加してもよい。１種または２種類以上の内部架橋剤を使用する場合には、最終的に得られる吸水剤の吸収特性等を考慮して、２個以上の重合性不飽和基を有する架橋性単量体を重合時に必須に用いることが好ましい。 The above internal cross-linking agents may be used alone or in combination of two or more. Moreover, the said internal crosslinking agent may be added to a reaction system all at once, and may be divided and added. When using one or more types of internal cross-linking agents, a cross-linkable monomer having two or more polymerizable unsaturated groups is used in consideration of the absorption characteristics of the finally obtained water-absorbing agent. It is preferably used at the time of polymerization.
　上記ポリシロキサンを内部架橋剤として用いる際の使用量は、上記の吸水性樹脂を得るために用いる酸基含有不飽和単量体１００質量部（架橋剤は除く）に対して、０．００１質量部以上、１０．０質量部以下であることが好ましく、０．０１質量部以上、５質量部以下であることがさらに好ましく、０．１質量部以上、１質量部以下であることが特に好ましい。上記内部架橋剤の使用量が０．００１質量部よりも少ない場合、並びに、１０質量部を超える場合には、吸水剤の十分な吸収特性が得られない可能性があるため、好ましくない。 The amount used when the polysiloxane is used as an internal crosslinking agent is 0.001 mass relative to 100 parts by mass of the acid group-containing unsaturated monomer (excluding the crosslinking agent) used to obtain the water-absorbent resin. It is preferably no less than 10.0 parts by mass, more preferably no less than 0.01 parts by mass and no greater than 5 parts by mass, and particularly preferably no less than 0.1 parts by mass and no greater than 1 part by mass. . When the amount of the internal crosslinking agent used is less than 0.001 part by mass, and when it exceeds 10 parts by mass, it is not preferable because sufficient absorption characteristics of the water absorbing agent may not be obtained.
　また、上記ポリシロキサン以外の内部架橋剤の使用量は、吸水性樹脂の良好な物性を得る観点から、上記の吸水性樹脂を得るために用いる不飽和単量体の総モル数（架橋剤は除く）に対して、好ましくは０．００１～２モル％、より好ましくは０．００５～０．５モル％、さらに好ましくは０．０１～０．２モル％、特に好ましくは０．０３～０．１５モル％の範囲内である。上記内部架橋剤の使用量が０．００１モル％よりも少ない場合、並びに、２モル％を超える場合には、吸水剤の十分な吸収特性が得られない可能性があるため、好ましくない。 In addition, the amount of the internal crosslinking agent other than the polysiloxane used is the total number of moles of unsaturated monomers used to obtain the water absorbent resin (crosslinking agent is from the viewpoint of obtaining good physical properties of the water absorbent resin. Is preferably 0.001 to 2 mol%, more preferably 0.005 to 0.5 mol%, still more preferably 0.01 to 0.2 mol%, and particularly preferably 0.03 to 0 mol%. Within the range of 15 mol%. When the amount of the internal cross-linking agent used is less than 0.001 mol% and exceeds 2 mol%, it is not preferable because sufficient absorption characteristics of the water absorbing agent may not be obtained.
　上記内部架橋剤を用いて架橋構造を重合体内部に導入する場合には、上記内部架橋剤を、上記不飽和単量体の重合前、重合途中あるいは重合後、または、中和後に反応系に添加すればよい。 When the crosslinked structure is introduced into the polymer using the internal crosslinking agent, the internal crosslinking agent is added to the reaction system before, during or after the polymerization of the unsaturated monomer, or after neutralization. What is necessary is just to add.
　すなわち、重合後に上記ポリシロキサンを反応系に添加してもよい。これにより、後述する乾燥処理工程において、含水ゲル状架橋重合体が加熱される際に、含水ゲル状架橋重合体を乾燥すると共に内部架橋を生じさせることができる。 That is, the polysiloxane may be added to the reaction system after polymerization. Thereby, in the drying process mentioned later, when a water-containing gel-like crosslinked polymer is heated, a water-containing gel-like crosslinked polymer can be dried and internal crosslinking can be caused.
　（６）不飽和単量体水溶液の調製
　重合工程において逆相懸濁重合や水溶液重合を行う場合、不飽和単量体は必要により内部架橋剤を含む水溶液とされるが、この水溶液（以下、単量体水溶液と称する）中の不飽和単量体成分の濃度は、物性面から好ましくは１０～７０質量％、より好ましくは１５～６５質量％、さらに好ましくは３０～６５質量％、特に好ましくは３０～６０質量％、最も好ましくは３５～５５質量％である。なお、水以外の溶媒を必要に応じて併用してもよく、併用して用いられる溶媒の種類は、特に限定されるものではない。 (6) Preparation of aqueous solution of unsaturated monomer When reverse phase suspension polymerization or aqueous solution polymerization is performed in the polymerization step, the unsaturated monomer is an aqueous solution containing an internal cross-linking agent as necessary. The concentration of the unsaturated monomer component in the aqueous monomer solution is preferably 10 to 70% by mass, more preferably 15 to 65% by mass, still more preferably 30 to 65% by mass, particularly preferably from the viewpoint of physical properties. Is 30 to 60% by mass, most preferably 35 to 55% by mass. A solvent other than water may be used in combination as necessary, and the type of solvent used in combination is not particularly limited.
　特に、本発明の製造方法の一例として、単量体水溶液にポリシロキサンを混合する場合、その混合方法については、特に限定されないが、好ましくは単量体ないし単量体水溶液に添加混合し不飽和単量体水溶液に調整される。 In particular, as an example of the production method of the present invention, when polysiloxane is mixed in an aqueous monomer solution, the mixing method is not particularly limited, but is preferably added to the monomer or aqueous monomer solution and mixed to be unsaturated. It is adjusted to a monomer aqueous solution.
　（７）重合工程
　本発明に用いられる吸水性樹脂を得るために上記の各単量体（不飽和単量体、他の不飽和単量体、架橋性単量体）を重合するに際しては、水溶液重合や逆相懸濁重合、バルク重合、沈殿重合等を行うことが可能である。 (7) Polymerization step When polymerizing each of the above monomers (unsaturated monomer, other unsaturated monomer, crosslinkable monomer) to obtain the water-absorbent resin used in the present invention, It is possible to perform aqueous solution polymerization, reverse phase suspension polymerization, bulk polymerization, precipitation polymerization, and the like.
　ここで、上記水溶性ポリシロキサンを架橋性単量体として用いる場合には、重合反応液に水溶性ポリシロキサンを均一に混合でき、重合の制御を容易に行うことができる観点から、上記単量体を水溶液とすることによる水溶液重合や逆相懸濁重合を行うことが好ましい。 Here, when the water-soluble polysiloxane is used as a crosslinkable monomer, from the viewpoint that the water-soluble polysiloxane can be uniformly mixed in the polymerization reaction solution and the polymerization can be easily controlled. It is preferable to perform aqueous solution polymerization or reverse phase suspension polymerization by making the body into an aqueous solution.
　なお、逆相懸濁重合とは、単量体水溶液を疎水性有機溶媒に、粒子状に懸濁させる重合法であり、例えば、米国特許第４０９３７７６号、同４３６７３２３号、同４４４６２６１号、同４６８３２７４号、同５２４４７３５号等の米国特許に記載されている。 The reverse phase suspension polymerization is a polymerization method in which an aqueous monomer solution is suspended in a hydrophobic organic solvent in the form of particles. For example, U.S. Pat. Nos. 4,093,767, 4,367,323, 4,446,261, and 4,683,274. And U.S. Pat. No. 5,244,735.
　一方、水溶液重合は、分散溶媒を用いずに単量体水溶液を重合する方法であり、例えば、米国特許第４６２５００１号、同４８７３２９９号、同４２８６０８２号、同４９７３６３２号、同４９８５５１８号、同５１２４４１６号、同５２５０６４０号、同５２６４４９５号、同５１４５９０６号、同５３８０８０８号等の米国特許や、欧州特許０８１１６３６号、同０９５５０８６号，同０９２２７１７号等の欧州特許に記載されている。これら米国特許や欧州特許に例示の単量体や重合開始剤等も本発明に適用できる。 On the other hand, aqueous solution polymerization is a method of polymerizing an aqueous monomer solution without using a dispersion solvent. For example, US Pat. Nos. 4,462,001, 4,873,299, 4,286,082, 4,973,632, 4,985,518, and 5,124,416 are used. No. 5,250,640, No. 5,264,495, No. 5,145,906 and No. 5,380,808, and European patents such as European Patent Nos. 081636, 09555086, and 0922717. Monomers and polymerization initiators exemplified in these US patents and European patents can also be applied to the present invention.
　上記の各単量体を水溶液として重合する場合の該水溶液（以下、「単量体水溶液」という）中の単量体の濃度は、水溶液の温度や単量体によって決まり、特に限定されるものではない。ただし、通常１０～８０質量％、好ましくは１０～７０質量％の範囲内、さらに好ましくは２０～６０質量％の範囲内である。また、上記水溶液重合を行う際には、水以外の溶媒を必要に応じて併用してもよく、併用される溶媒の種類は、特に限定されるものではない。 In the case where the above monomers are polymerized as an aqueous solution, the concentration of the monomer in the aqueous solution (hereinafter referred to as “monomer aqueous solution”) depends on the temperature of the aqueous solution and the monomer and is particularly limited. is not. However, it is usually in the range of 10 to 80% by mass, preferably in the range of 10 to 70% by mass, and more preferably in the range of 20 to 60% by mass. Moreover, when performing the said aqueous solution polymerization, you may use together solvents other than water as needed, and the kind of solvent used together is not specifically limited.
　上記の重合を開始させる際には、上記重合開始剤を使用することができる。また、上記重合開始剤の他にも、紫外線や電子線、γ線等の活性エネルギー線を、単独あるいは重合開始剤とともに用いてもよい。上記重合反応における反応温度は、使用する重合開始剤の種類にもよるが、重合中の下限～上限温度で、１５～１３０℃の範囲が好ましく、２０～１２０℃の範囲がより好ましい。反応温度が上記の範囲をはずれると、得られる吸水性樹脂の残存単量体の増加や、過度の自己架橋反応の進行により、吸水性樹脂の吸水性能が低下するおそれがあるので好ましくない。 When starting the above polymerization, the above polymerization initiator can be used. In addition to the polymerization initiator, active energy rays such as ultraviolet rays, electron beams, and γ rays may be used alone or in combination with the polymerization initiator. The reaction temperature in the above polymerization reaction depends on the type of polymerization initiator used, but is preferably in the range of 15 to 130 ° C., more preferably in the range of 20 to 120 ° C., as the lower limit to the upper limit temperature during the polymerization. If the reaction temperature is out of the above range, the water absorption performance of the water absorbent resin may be deteriorated due to an increase in residual monomers of the obtained water absorbent resin or excessive self-crosslinking reaction, which is not preferable.
　本発明の吸水剤の好ましい製造方法の一例としては、水溶性ポリシロキサンが重合時の単量体水溶液に前記の量に調整され混合される。なお、重合時の単量体水溶液とは重合前の単量体水溶液に限定されず、重合途中の単量体水溶液や該水溶性を含むゲル状物を含む概念であり、単量体の重合率が０～９９モル％、さらには０～７０モル％、特に０～５０モル％の段階で１回以上添加すればよい。 As an example of a preferred method for producing the water-absorbing agent of the present invention, a water-soluble polysiloxane is adjusted to the above amount and mixed with an aqueous monomer solution during polymerization. In addition, the monomer aqueous solution at the time of polymerization is not limited to the monomer aqueous solution before polymerization, and is a concept including a monomer aqueous solution in the middle of polymerization and a gel-like substance containing the water solubility. It may be added one or more times at a stage where the rate is 0 to 99 mol%, further 0 to 70 mol%, particularly 0 to 50 mol%.
　製造方法の一例として、水溶性ポリシロキサンを重合工程で単量体水溶液に添加する場合は、重合開始剤投入前後のいずれのタイミングでも混合することができ、その混合のタイミングや混合方法は特に限定されるものではないが、好ましくは重合前の単量体水溶液（重合率０％）に添加される。 As an example of the production method, when water-soluble polysiloxane is added to the monomer aqueous solution in the polymerization step, it can be mixed at any timing before and after the introduction of the polymerization initiator, and the timing and method of mixing are particularly limited. However, it is preferably added to the monomer aqueous solution (polymerization rate 0%) before polymerization.
　（８）含水ゲルの細分化工程
　重合工程で得られた含水ゲル状架橋重合体（以下、含水ゲル）は水溶液重合の場合、そのまま乾燥を行ってもよいが、必要によりゲル粉砕機などを用いてゲル粉砕され、粒子状にされる。ゲル粉砕時の含水ゲルの温度は物性面から、好ましくは４０～９５℃、さらには５０～８０℃に保温ないし加熱される。 (8) Hydrogel subdivision process The hydrogel crosslinked polymer obtained in the polymerization process (hereinafter, hydrogel) may be dried as it is in the case of aqueous solution polymerization, but if necessary, a gel grinder or the like may be used. The gel is pulverized into particles. The temperature of the water-containing gel at the time of gel pulverization is preferably kept at 40 to 95 ° C., more preferably 50 to 80 ° C. from the viewpoint of physical properties.
　含水ゲルの樹脂固形分は、特に限定されるものではないが、物性面から好ましくは１０～７０質量％、より好ましくは１５～６５質量％、さらに好ましくは３０～５５質量％である。 The resin solid content of the hydrated gel is not particularly limited, but is preferably 10 to 70% by mass, more preferably 15 to 65% by mass, and further preferably 30 to 55% by mass from the viewpoint of physical properties.
　ゲル粉砕は重合時または重合後に行われ、好ましくは、連続ニーダーや孔径０．３～３０ｍｍ、より好ましくは５～３０ｍｍ、さらに好ましくは５～２０ｍｍの多孔構造から押し出して粉砕することが可能である。孔の形状としては、円形、正方形、長方形、などの四方形、三角形、六角形など、特に限定されないが、好ましくは、円形の孔から押し出される。なお、前記の孔径とは、目開き部の外周を円の外周に換算した場合の直径で規定できる。 The gel pulverization is performed at the time of polymerization or after polymerization, and can be preferably pulverized by extrusion from a continuous kneader or a porous structure having a pore diameter of 0.3 to 30 mm, more preferably 5 to 30 mm, and even more preferably 5 to 20 mm. . The shape of the hole is not particularly limited, such as a quadrangle such as a circle, a square, and a rectangle, a triangle, and a hexagon. However, the hole is preferably extruded from a circular hole. In addition, the said hole diameter can be prescribed | regulated by the diameter at the time of converting the outer periphery of an opening part into the outer periphery of a circle | round | yen.
　多孔構造の孔径が０．３ｍｍよりも小さいと、ゲルが紐状になったり、あるいはゲルを押出すことができなくなったりするおそれがある。多孔構造の孔径が３０ｍｍよりも大きいと、含水ゲルの乾燥が不十分となるため、本発明の効果を発揮することができないおそれがある。 If the pore diameter of the porous structure is smaller than 0.3 mm, the gel may become a string or the gel may not be extruded. When the pore diameter of the porous structure is larger than 30 mm, the water-containing gel is not sufficiently dried, so that the effects of the present invention may not be exhibited.
　押し出し粉砕装置としては、例えば、スクリュー型、回転ロール型によるもの等、含水ゲル状重合体をその供給口から多孔板に圧送できる形式のものが用いられる。スクリュー型押し出し機は、一軸あるいは多軸でもよく、通常、食肉、ゴム、プラスチックの押し出し成型に使用されるもの、あるいは、粉砕機として使用されるものでもよい。例えば、ミートチョッパーやドームグランが挙げられる。 As the extrusion pulverization apparatus, for example, a screw type, a rotary roll type, or the like that can pressure-feed the hydrogel polymer from its supply port to the perforated plate is used. The screw-type extruder may be uniaxial or multi-axial, and may normally be used for extrusion molding of meat, rubber and plastic, or may be used as a pulverizer. For example, meat chopper and dome gran are mentioned.
　この場合、水や内部架橋剤の例示に記載の多価アルコール、水と多価アルコールの混合液、水に内部架橋剤の例示に記載の多価金属を溶解した溶液あるいはこれらの蒸気等を添加してもよい。 In this case, water or a polyhydric alcohol described in the example of the internal cross-linking agent, a mixed solution of water and polyhydric alcohol, a solution in which the polyvalent metal described in the example of the internal cross-linking agent is dissolved in water, or a vapor thereof is added. May be.
　本発明の吸水剤の好ましい製造方法の一例としては、水溶性ポリシロキサンを含水ゲルの整粒（細分化）時に混合する。 As an example of a preferable method for producing the water-absorbing agent of the present invention, a water-soluble polysiloxane is mixed at the time of sizing (subdividing) the water-containing gel.
　（９）乾燥工程
　上記重合方法によって単量体を重合して得られる重合体は、通常、含水ゲル状架橋重合体であり、必要に応じて乾燥処理や粉砕が行われる。粉砕は、通常、乾燥処理の前および／または後に行われる。含水ゲル状架橋重合体を乾燥することによって、含水ゲル状架橋重合体乾燥物を得ることができる。 (9) Drying Step The polymer obtained by polymerizing the monomer by the above polymerization method is usually a hydrogel crosslinked polymer, and is subjected to drying treatment or pulverization as necessary. The grinding is usually performed before and / or after the drying process. By drying the hydrogel crosslinked polymer, a dried hydrogel crosslinked polymer can be obtained.
　また、乾燥処理方法としては、加熱乾燥、熱風乾燥、減圧乾燥、赤外線乾燥、マイクロ波乾燥、疎水性有機溶媒との共沸による脱水、高温の水蒸気を用いた高湿乾燥等、目的の含水率となるように種々の方法を採用することができ、特に限定されるものではない。乾燥処理を熱風乾燥にて行う場合には、通常６０℃～２５０℃、好ましくは１００℃～２２０℃、より好ましくは１２０℃～２００℃の温度範囲（熱風温度）で行われる。乾燥時間は、重合体の表面積、含水率及び乾燥機の種類に依存し、目的とする含水率になるよう選択される。例えば、乾燥時間は、１分～５時間の範囲内で適宜選択すればよい。 The drying method includes heat drying, hot air drying, vacuum drying, infrared drying, microwave drying, dehydration by azeotropy with a hydrophobic organic solvent, and high moisture drying using high-temperature steam. Various methods can be adopted so as to be, and there is no particular limitation. When the drying treatment is performed by hot air drying, it is usually performed in a temperature range (hot air temperature) of 60 ° C. to 250 ° C., preferably 100 ° C. to 220 ° C., more preferably 120 ° C. to 200 ° C. The drying time depends on the surface area of the polymer, the moisture content, and the type of dryer, and is selected to achieve the desired moisture content. For example, the drying time may be appropriately selected within the range of 1 minute to 5 hours.
　本発明に用いることのできる吸水性樹脂の含水率（吸水性樹脂や吸水剤中に含まれる水分量で規定／１８０℃で３時間の乾燥減量を測定し、該減量を、乾燥前の吸水性樹脂に対する比率で表わしたもの）は、特に限定されない。ただし、該吸水性樹脂を主成分として含む本発明の吸水剤の良好な物性を得るために、室温でも流動性を示す粒子（粉末）となるように制御可能な含水率であることが好ましい。即ち、上記吸水剤は、好ましくは含水率が０～３０質量％の粉末状態、より好ましくは０．２～３０質量％の粉末状態、より好ましくは０．２～２０質量％の粉末状態、さらに好ましくは０．３～１５質量％の粉末状態、特に好ましくは０．５～１０質量％の粉末状態である。上記の範囲内の含水率を有する吸水剤が得られるように、含水ゲル状架橋重合体を乾燥処理して、吸水性樹脂を得ればよい。含水率が高くなってしまうと、流動性が悪くなり製造に支障をきたすばかりか、吸水性樹脂が粉砕できなくなり、特定の粒度分布に制御できなくなってしまうおそれがある。 Water content of the water-absorbent resin that can be used in the present invention (specified by the amount of water contained in the water-absorbent resin or water-absorbing agent / measured for 3 hours of loss on drying at 180 ° C. The ratio expressed by the ratio to the resin is not particularly limited. However, in order to obtain good physical properties of the water-absorbing agent of the present invention containing the water-absorbing resin as a main component, it is preferable that the water content is controllable so that particles (powder) exhibiting fluidity at room temperature. That is, the water-absorbing agent is preferably in a powder state with a water content of 0 to 30% by mass, more preferably in a powder state of 0.2 to 30% by mass, more preferably in a powder state of 0.2 to 20% by mass, The powder state is preferably 0.3 to 15% by mass, and particularly preferably 0.5 to 10% by mass. What is necessary is just to dry-process a water-containing gel-like crosslinked polymer, and to obtain a water absorbing resin so that the water absorbing agent which has the water content in said range may be obtained. If the water content becomes high, the fluidity is deteriorated and the production is hindered, and the water-absorbent resin cannot be pulverized and may not be controlled to a specific particle size distribution.
　なお、上記逆相懸濁重合による重合方法を用いた場合には、通常、重合反応終了後に得られる含水ゲル状架橋重合体を、例えばヘキサン等の炭化水素の有機溶媒中に分散させた状態で共沸脱水し、重合体の含水率を４０質量％以下（下限０質量％、好ましくは５質量％）、好ましくは３０質量％以下とした後に、デカンテーションあるいは蒸発により有機溶媒と分離し、必要に応じて乾燥処理することができる。また、本発明の吸水性樹脂は、重合中または重合後に、後述する表面架橋剤、通液性向上剤、滑り性向上剤等が添加混合され得る。重合後に添加混合する場合には、乾燥前、乾燥後または粉砕後に添加混合することができる。 In the case of using the polymerization method by reverse phase suspension polymerization, the hydrogel crosslinked polymer obtained after the completion of the polymerization reaction is usually dispersed in a hydrocarbon organic solvent such as hexane. After azeotropic dehydration, the water content of the polymer is adjusted to 40% by mass or less (lower limit 0% by mass, preferably 5% by mass), preferably 30% by mass or less, and then separated from the organic solvent by decantation or evaporation. Depending on the case, it can be dried. In addition, the water-absorbent resin of the present invention may be added and mixed with a surface cross-linking agent, a liquid permeability improver, a slipperiness improver, etc., which will be described later, during or after polymerization. In the case of addition and mixing after polymerization, the addition and mixing can be performed before drying, after drying or after pulverization.
　（１０）乾燥後の粒度および調製
　前述の含水ゲル状架橋重合体を乾燥する工程後、必要により乾燥後に粒度を調整してもよいが、後述の表面架橋での物性向上のため、好ましくは特定粒度にされる。粒度は重合（特に逆相懸濁重合）、粉砕、分級、造粒、微粉回収などで適宜調整できる。 (10) Particle size and preparation after drying The particle size may be adjusted after drying after the step of drying the water-containing gel-like crosslinked polymer described above, but it is preferably specified for improving the physical properties in surface crosslinking described later. Granulated. The particle size can be appropriately adjusted by polymerization (particularly reversed phase suspension polymerization), pulverization, classification, granulation, fine powder recovery and the like.
　表面架橋前の質量平均粒子径（Ｄ５０）としては２００～６００μｍ、好ましくは２００～５５０μｍ、より好ましくは２５０～５００μｍ、特に好ましくは３５０～４５０μｍに調整される。また、１５０μｍ未満の粒子が少ないほどよく、通常０～５質量％、好ましくは０～３質量％、特に好ましくは０～１質量％に調整される。さらに、８５０μｍ以上の粒子が少ないほどよく、通常０～５質量％、好ましくは０～３質量％、特に好ましくは０～１質量％に調整される。粒度分布の対数標準偏差（σζ）が好ましくは０．２０～０．４０、好ましくは０．２７～０．３７、好ましくは０．２５～０．３５とされる。 The mass average particle diameter (D50) before surface crosslinking is adjusted to 200 to 600 μm, preferably 200 to 550 μm, more preferably 250 to 500 μm, and particularly preferably 350 to 450 μm. Further, the smaller the particle size is less than 150 μm, the better, and it is usually adjusted to 0 to 5% by mass, preferably 0 to 3% by mass, particularly preferably 0 to 1% by mass. Further, the smaller the number of particles of 850 μm or more, the better. Usually, it is adjusted to 0 to 5% by mass, preferably 0 to 3% by mass, particularly preferably 0 to 1% by mass. The logarithmic standard deviation (σζ) of the particle size distribution is preferably 0.20 to 0.40, preferably 0.27 to 0.37, and preferably 0.25 to 0.35.
　（１１）表面架橋工程
　吸水性樹脂の表面架橋とは、重合体内部に均一な架橋構造を吸水性樹脂の表面層（表面近傍：通常数１０μｍ以下の近傍）にさらに架橋密度の高い部分を設けることであり、表面でのラジカル架橋や表面重合で高架橋層を形成してもよく、表面架橋剤との架橋反応で表面架橋してもよい。以下、本発明で必要により行なわれる表面架橋剤による表面架橋についてさらに説明する。 (11) Surface cross-linking step The surface cross-linking of the water-absorbent resin is to provide a uniform cross-linked structure inside the polymer with a portion having a higher cross-linking density in the surface layer of the water-absorbent resin (near the surface: usually several tens of microns or less) That is, a highly crosslinked layer may be formed by radical crosslinking or surface polymerization on the surface, or surface crosslinking may be performed by a crosslinking reaction with a surface crosslinking agent. Hereinafter, the surface cross-linking by the surface cross-linking agent performed as necessary in the present invention will be further described.
　本発明で用いられる表面架橋剤としては、種々の有機または無機架橋剤があるが、物性の観点から、カルボキシル基と反応し得る架橋剤、特に有機表面架橋剤、一般的には、多価アルコール化合物、エポキシ化合物、多価アミン化合物またはそのハロエポキシ化合物との縮合物、オキサゾリン化合物、モノ、ジ、またはポリオキサゾリジノン化合物、多価金属塩、アルキレンカーボネート化合物等が用いられている。 The surface cross-linking agent used in the present invention includes various organic or inorganic cross-linking agents. From the viewpoint of physical properties, cross-linking agents capable of reacting with carboxyl groups, particularly organic surface cross-linking agents, generally polyhydric alcohols. Compounds, epoxy compounds, polyvalent amine compounds or their condensates with haloepoxy compounds, oxazoline compounds, mono-, di- or polyoxazolidinone compounds, polyvalent metal salts, alkylene carbonate compounds, and the like are used.
　上記表面近傍に架橋を行うための表面架橋剤としては、種々のものがあるが、上記ポリシロキサンを用いることができる。上記ポリシロキサンは解離基、好ましくはアミノ基を有しているため、吸水性樹脂の官能基と反応し得、吸水性樹脂表面を架橋することができる。これによって、ポリシロキサンを含む吸水剤を得ることができ、ポリシロキサンによって表面架橋された新たな吸水剤を提供することができる。 There are various surface crosslinking agents for crosslinking in the vicinity of the surface, and the polysiloxane can be used. Since the polysiloxane has a dissociation group, preferably an amino group, it can react with a functional group of the water-absorbent resin and can crosslink the surface of the water-absorbent resin. Thereby, a water-absorbing agent containing polysiloxane can be obtained, and a new water-absorbing agent surface-crosslinked with polysiloxane can be provided.
　また、上記ポリシロキサン以外の表面架橋剤として、上記吸水性樹脂の官能基と反応し得る官能基を２個以上有する化合物を表面架橋剤として用いることができる。通常、吸収性能の観点から、多価アルコール化合物、エポキシ化合物、ポリエポキシ化合物、多価アミン化合物またはそのハロエポキシ化合物との縮合物、オキサゾリン化合物、モノ，ジまたはポリオキサゾリジノン化合物、多価金属塩、アルキレンカーボネート化合物等を用いることができる。 Further, as the surface cross-linking agent other than the polysiloxane, a compound having two or more functional groups capable of reacting with the functional group of the water-absorbent resin can be used as the surface cross-linking agent. Usually, from the viewpoint of absorption performance, polyhydric alcohol compounds, epoxy compounds, polyepoxy compounds, polyvalent amine compounds or their condensates with haloepoxy compounds, oxazoline compounds, mono-, di- or polyoxazolidinone compounds, polyvalent metal salts, alkylene A carbonate compound or the like can be used.
　本発明で用いられる表面架橋剤としては、具体的には、米国特許６２２８９３０号、同６０７１９７６号、同６２５４９９０号などに例示されている。例えば、モノ，ジ，トリ，テトラまたはポリエチレングリコール、モノプロピレングリコール、１，３－プロパンジオール、ジプロピレングリコール、２，３，４－トリメチル－１，３－ペンタンジオール、ポリプロピレングリコール、グリセリン、ポリグリセリン、２－ブテン－１，４－ジオール、１，４－ブタンジオール、１，３－ブタンジオール、１，５－ペンタンジオール、１，６－ヘキサンジオール、１，２－シクロヘキサンジメタノールなどの多価アルコール化合物、エチレングリコールジグリシジルエーテルやグリシドールなどのエポキシ化合物、エチレンジアミン、ジエチレントリアミン、トリエチレンテトラミン、テトラエチレンペンタミン、ペンタエチレンヘキサミン、ポリエチレンイミン、ポリアミドポリアミン等の多価アミン化合物；エピクロロヒドリン、エピブロムヒドリン、α－メチルエピクロロヒドリン等のハロエポキシ化合物；上記多価アミン化合物と上記ハロエポキシ化合物との縮合物、２－オキサゾリジノンなどのキサゾリジノン化合物、エチレンカーボネートなどのアルキレンカーボネート化合物等が挙げられるが、特に限定されるものではない。本発明の効果を最大限にするために、これらの架橋剤の中でも少なくとも多価アルコールを用いることが好ましく、炭素数２～１０、好ましくは炭素数３～８の多価アルコールが用いられる。 Specific examples of the surface cross-linking agent used in the present invention are exemplified in US Pat. Nos. 6,228,930, 6071976, and 6254990. For example, mono, di, tri, tetra or polyethylene glycol, monopropylene glycol, 1,3-propanediol, dipropylene glycol, 2,3,4-trimethyl-1,3-pentanediol, polypropylene glycol, glycerin, polyglycerin , 2-butene-1,4-diol, 1,4-butanediol, 1,3-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,2-cyclohexanedimethanol, etc. Alcohol compounds, epoxy compounds such as ethylene glycol diglycidyl ether and glycidol, ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, polyethyleneimine, polyamide polyamine, etc. Haloepoxy compounds such as epichlorohydrin, epibromohydrin, α-methylepichlorohydrin; condensates of the above polyvalent amine compounds with the above haloepoxy compounds, xazolidinone compounds such as 2-oxazolidinone, ethylene carbonate Examples thereof include, but are not limited to, alkylene carbonate compounds. In order to maximize the effect of the present invention, it is preferable to use at least a polyhydric alcohol among these crosslinking agents, and polyhydric alcohols having 2 to 10 carbon atoms, preferably 3 to 8 carbon atoms are used.
　表面架橋剤の使用量は、用いる化合物やそれらの組み合わせ等にもよるが、樹脂の固形分１００質量部に対して、０．００１質量部～１０質量部の範囲内が好ましく、０．０１質量部～５質量部の範囲内がより好ましい。本発明において、表面架橋には水を用いることが好ましい。この際、使用される水の量は、使用する吸水性樹脂の含水率にもよるが、通常、吸水性樹脂１００質量部に対し、好ましくは０．５～２０質量部、より好ましくは０．５～１０質量部の範囲である。 The amount of the surface cross-linking agent used depends on the compounds used, combinations thereof, and the like, but is preferably in the range of 0.001 to 10 parts by mass with respect to 100 parts by mass of the resin solids, 0.01 mass More preferably within the range of 5 parts by mass to 5 parts by mass. In the present invention, water is preferably used for surface crosslinking. At this time, although the amount of water used depends on the water content of the water-absorbing resin to be used, it is usually preferably 0.5 to 20 parts by weight, more preferably 0.8 parts per 100 parts by weight of the water-absorbing resin. It is in the range of 5 to 10 parts by mass.
　表面架橋剤の使用量は、用いる化合物やそれらの組み合わせ等にもよるが、吸水性樹脂１００質量部（質量部）に対して、０．００１質量部～１０質量部の範囲内が好ましく、０．０１質量部～５質量部の範囲内がより好ましい。 The amount of the surface cross-linking agent used is preferably in the range of 0.001 to 10 parts by mass with respect to 100 parts by mass (parts by mass) of the water-absorbing resin, although it depends on the compounds to be used and combinations thereof. A range of 0.01 parts by mass to 5 parts by mass is more preferable.
　上記表面架橋処理には、水を用いることが好ましい。この際、使用される水の量は、使用する吸水性樹脂の含水率にもよるが、好ましくは吸水性樹脂１００質量部に対し０．５～２０質量部、より好ましくは０．５～１０質量部の範囲内である。 It is preferable to use water for the surface cross-linking treatment. At this time, the amount of water used depends on the water content of the water absorbent resin to be used, but is preferably 0.5 to 20 parts by mass, more preferably 0.5 to 10 parts by mass with respect to 100 parts by mass of the water absorbent resin. Within the range of parts by mass.
　また、上記表面架橋処理には、水に代えて、親水性有機溶媒を用いてもよく、水と親水性有機溶媒との混合溶媒を用いてもよい。この際使用される親水性有機溶媒または混合溶媒の量は、吸水性樹脂１００質量部に対して０～１０質量部、好ましくは０～５質量部、より好ましくは０～３質量部の範囲内である。 Further, in the surface cross-linking treatment, a hydrophilic organic solvent may be used instead of water, or a mixed solvent of water and a hydrophilic organic solvent may be used. The amount of the hydrophilic organic solvent or mixed solvent used in this case is in the range of 0 to 10 parts by weight, preferably 0 to 5 parts by weight, more preferably 0 to 3 parts by weight with respect to 100 parts by weight of the water absorbent resin. It is.
　上記表面架橋剤の添加は、種々の手法で行うことができる。ただし、表面架橋剤を、必要により水および／または親水性有機溶媒と予め混合した後、吸水性樹脂に噴霧あるいは滴下混合する方法が好ましく、噴霧する方法がより好ましい。噴霧する方法の場合には、噴霧される液滴の大きさは、平均粒子径で０．１～３００μｍの範囲内が好ましく、０．１～２００μｍの範囲がより好ましい。 The addition of the surface cross-linking agent can be performed by various methods. However, a method in which the surface cross-linking agent is preliminarily mixed with water and / or a hydrophilic organic solvent, if necessary, and then sprayed or dropped into the water-absorbent resin is preferable, and a method of spraying is more preferable. In the case of the spraying method, the size of droplets to be sprayed is preferably in the range of 0.1 to 300 μm, more preferably in the range of 0.1 to 200 μm, in terms of average particle diameter.
　吸水性樹脂と、表面架橋剤と、水または親水性有機溶媒とを混合する際に用いられる混合装置は、これら各物質を均一に、かつ確実に混合するために、大きな混合力を備えていることが好ましい。上記の混合装置としては例えば、円筒型混合機、二重壁円錐混合機、高速攪拌型混合機、Ｖ字型混合機、リボン型混合機、スクリュー型混合機、双腕型ニーダー、粉砕型ニーダー、回転式混合機、気流型混合機、タービュライザー、バッチ式レディゲミキサー、連続式レディゲミキサー等が好適である。 The mixing device used when mixing the water-absorbing resin, the surface cross-linking agent, and water or a hydrophilic organic solvent has a large mixing force in order to mix these substances uniformly and reliably. It is preferable. Examples of the mixing apparatus include a cylindrical mixer, a double wall conical mixer, a high-speed stirring mixer, a V-shaped mixer, a ribbon mixer, a screw mixer, a double-arm kneader, and a pulverizing kneader. Rotating mixers, airflow mixers, turbulators, batch-type Redige mixers, continuous-type Redige mixers, and the like are suitable.
　なお、表面架橋剤の混合に際しては、表面架橋前に炭素数７以上の炭化水素基を側鎖に有する高分子添加剤と混合したり、または、表面架橋剤と共存させたりしても、本発明の吸水剤を得ることができる。また、表面架橋剤の混合に際し、本発明の効果を妨げない範囲で、水不溶性微粒子粉体を共存させてもよい。 When mixing the surface cross-linking agent, it may be mixed with a polymer additive having a hydrocarbon group having 7 or more carbon atoms in the side chain before the surface cross-linking or coexisting with the surface cross-linking agent. The water-absorbing agent of the invention can be obtained. In addition, when mixing the surface cross-linking agent, water-insoluble fine particle powder may be allowed to coexist within a range that does not hinder the effects of the present invention.
　表面架橋剤を混合後の吸水性樹脂は、加熱処理されることが好ましい。上記加熱処理を行う際の条件としては、加熱温度（吸水性樹脂温度若しくは熱媒温度）は、好ましくは１００～２５０℃、より好ましくは１５０～２５０℃である。また、加熱時間は、好ましくは１分～２時間の範囲である。加熱温度と加熱時間との組み合わせの好適な例としては、１８０℃で０．１～１．５時間、２００℃で０．１～１時間である。また、加熱後の吸水性樹脂は必要に応じて冷却してもよい。 The water-absorbing resin after mixing the surface cross-linking agent is preferably heat-treated. As conditions for performing the above heat treatment, the heating temperature (water absorbent resin temperature or heat medium temperature) is preferably 100 to 250 ° C., more preferably 150 to 250 ° C. The heating time is preferably in the range of 1 minute to 2 hours. Preferable examples of the combination of the heating temperature and the heating time are 180 ° C. for 0.1 to 1.5 hours and 200 ° C. for 0.1 to 1 hour. Moreover, you may cool the water absorbing resin after a heating as needed.
　また、本発明における表面架橋処理の別の形態としては、ラジカル重合性化合物を含む処理液を吸水性樹脂に添加した後に、活性エネルギーを照射して表面架橋処理する方法が挙げられ、例えば、日本国公開特許公報「特開２００３－３０３３０６号公報」に記載されている。また、上記処理液に界面活性剤を添加し、活性エネルギーを照射して表面架橋処理することもできる。さらに、本発明における表面架橋処理の別の形態としては、過酸化物ラジカル開始剤を含む水性溶液を吸水性樹脂に添加した後に、加熱して表面架橋処理する方法が挙げられ、例えば日本国公告特許公報「特公平７－８８８３号公報」に記載されている。 Further, as another form of the surface cross-linking treatment in the present invention, there is a method of performing surface cross-linking treatment by irradiating active energy after adding a treatment liquid containing a radical polymerizable compound to the water absorbent resin. It is described in a national published patent publication “Japanese Patent Laid-Open No. 2003-303306”. Moreover, a surface active agent can also be added to the said process liquid, and an active energy can be irradiated and surface crosslinking can also be performed. Furthermore, as another form of the surface cross-linking treatment in the present invention, there is a method in which an aqueous solution containing a peroxide radical initiator is added to the water-absorbent resin, followed by heating and surface cross-linking treatment. It is described in the patent publication “Japanese Patent Publication No. 7-8883”.
　（１２）表面架橋工程後にポリシロキサンを添加する工程
　さらに、含水ゲル状重合体に表面架橋処理が施された含水ゲル状架橋重合体乾燥物に、本発明に係る水溶性ポリシロキサンを作用させ、含水ゲル状架橋重合体乾燥物の表面を共有結合および／またはイオン結合によって表面架橋することができる。これによっても、ポリシロキサンを含む吸水剤を得ることができる。なお、含水ゲル状架橋重合体乾燥物に水溶性ポリシロキサンを作用させるタイミングは、特に限定されない。 (12) Step of adding polysiloxane after the surface cross-linking step Furthermore, the water-soluble gel-like crosslinked polymer obtained by subjecting the water-containing gel-like polymer to surface cross-linking treatment is allowed to act on the water-soluble polysiloxane according to the present invention, The surface of the dried hydrogel crosslinked polymer can be surface-crosslinked by covalent bonding and / or ionic bonding. Also by this, the water absorbing agent containing polysiloxane can be obtained. In addition, the timing which makes water-soluble polysiloxane act on a hydrogel crosslinked polymer dried material is not specifically limited.
　表面架橋された吸水性樹脂にポリシロキサンを作用させる方法としては、特に限定されるものではないが、例えば、ポリシロキサンを水または親水性有機溶媒に溶解し、上記吸水性樹脂と混合すればよい。混合装置としては、例えば、円筒型混合機、二重壁円錐混合機、高速攪拌型混合機、Ｖ字型混合機、リボン型混合機、スクリュー型混合機、双腕型ニーダー、粉砕型ニーダー、回転式混合機、気流型混合機、タービュライザー、バッチ式レディゲミキサー、連続式レディゲミキサー等が好適である。 A method for allowing polysiloxane to act on the surface-crosslinked water-absorbing resin is not particularly limited. For example, polysiloxane may be dissolved in water or a hydrophilic organic solvent and mixed with the water-absorbing resin. . As a mixing apparatus, for example, a cylindrical mixer, a double wall cone mixer, a high-speed stirring mixer, a V-shaped mixer, a ribbon mixer, a screw mixer, a double-arm kneader, a pulverizing kneader, A rotary mixer, an airflow mixer, a turbulizer, a batch-type Redige mixer, a continuous-type Redige mixer, and the like are suitable.
　水溶性ポリシロキサンの使用量は、吸水性樹脂１００質量部に対して、０．０１～２０質量部の範囲内が好ましく、より好ましくは０．１～１０質量部の範囲である。 The amount of water-soluble polysiloxane used is preferably in the range of 0.01 to 20 parts by mass, more preferably in the range of 0.1 to 10 parts by mass, with respect to 100 parts by mass of the water-absorbing resin.
　本発明の吸水剤の好ましい製造例の一例としては、水溶性ポリシロキサンは均一な添加のために溶液、さらには水溶液ないしは水性液とされ、表面架橋された吸水性樹脂に溶液として添加される。溶液の濃度は１～５０質量％でよい。さらには、必要により、親水性有機溶媒を用いてもよい。 As an example of a preferred production example of the water-absorbing agent of the present invention, the water-soluble polysiloxane is made into a solution for uniform addition, further an aqueous solution or an aqueous solution, and added as a solution to the surface-crosslinked water-absorbing resin. The concentration of the solution may be 1 to 50% by mass. Further, if necessary, a hydrophilic organic solvent may be used.
　＜吸水剤に含まれるその他の成分＞
　本発明の吸水剤においては、さらに必要に応じて、界面活性剤、消臭剤、抗菌剤、香料、発泡剤、顔料、染料、親水性短繊維、可塑剤、粘着剤、肥料、酸化剤、還元剤、水、塩類、キレート剤、殺菌剤、着色防止剤、ポリエチレングリコールやポリエリレンイミン等の親水性高分子、パラフィン等の疎水性高分子、ポリエチレンやポリプロピレン等の熱可塑性樹脂、ポリエステル樹脂やユリア樹脂等の熱硬化性樹脂等を添加する等、種々の機能を付与する工程を含んでいてもよい。これらの添加剤の使用量は、吸水性樹脂１００重量部に対して通常０～３０重量部、好ましくは０～１０重量部の範囲、より好ましくは０～１重量部の範囲である。 <Other components contained in water-absorbing agent>
In the water-absorbing agent of the present invention, if necessary, a surfactant, a deodorant, an antibacterial agent, a fragrance, a foaming agent, a pigment, a dye, a hydrophilic short fiber, a plasticizer, an adhesive, a fertilizer, an oxidizing agent, Reducing agent, water, salt, chelating agent, bactericidal agent, anti-coloring agent, hydrophilic polymer such as polyethylene glycol and polyerylenimine, hydrophobic polymer such as paraffin, thermoplastic resin such as polyethylene and polypropylene, polyester resin And a step of adding various functions such as addition of a thermosetting resin such as urea resin. The amount of these additives to be used is usually 0 to 30 parts by weight, preferably 0 to 10 parts by weight, more preferably 0 to 1 part by weight with respect to 100 parts by weight of the water absorbent resin.
　吸水剤とこれらの添加剤との混合方法は、特に限定されるものではなく、例えば粉体同士を混合するドライブレンド法、湿式混合法（添加剤を溶媒に分散ないし溶解させ添加）等を採用できる。 The mixing method of the water-absorbing agent and these additives is not particularly limited. For example, a dry blend method in which powders are mixed with each other, a wet blend method (addition is performed by dispersing or dissolving the additive in a solvent), etc. are adopted. it can.
　これらの製造工程を終えた後に、本発明に係る吸水剤が得られる。なお、本発明は、上述した各実施形態に限定されるものではなく、請求項に示した範囲で種々の変更が可能であり、異なる実施形態にそれぞれ開示された技術的手段を適宜組み合わせて得られる実施形態についても本発明の技術的範囲に含まれる。 After completing these manufacturing steps, the water-absorbing agent according to the present invention is obtained. The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope shown in the claims, and the present invention can be obtained by appropriately combining technical means disclosed in different embodiments. Such embodiments are also included in the technical scope of the present invention.
　（１３）吸水剤
　本発明に係る吸水剤は、酸基含有不飽和単量体由来の構成単位を有する吸水性樹脂と、解離基、好ましくはアミノ基を有する水溶性ポリシロキサンとを含んでいる。また、より好ましくは、上記水溶性ポリシロキサンは、上述した化学式（１）～化学式（４）で示される少なくとも何れかの分子構造を有している。 (13) Water-absorbing agent The water-absorbing agent according to the present invention contains a water-absorbing resin having a structural unit derived from an acid group-containing unsaturated monomer and a water-soluble polysiloxane having a dissociating group, preferably an amino group. . More preferably, the water-soluble polysiloxane has at least one molecular structure represented by the chemical formulas (1) to (4).
　上記アミン構造の水溶性ポリシロキサンは、例えば、製造工程等において、水溶性ポリシロキサンと吸水性樹脂とが共有結合することによって、水溶性ポリシロキサンにおける水素原子およびマイナスイオンＺが脱離することによって生じる。 The water-soluble polysiloxane having the amine structure is formed by, for example, a covalent bond between the water-soluble polysiloxane and the water-absorbent resin in the production process, and the elimination of hydrogen atoms and negative ions Z in the water-soluble polysiloxane. Arise.
　本発明に係る吸水剤の形状としては、例えば、シート状、繊維状などが挙げられ、特に好ましくは粒子状、または、球状である。また、上記吸水剤は造粒物であってもよい。 The shape of the water-absorbing agent according to the present invention includes, for example, a sheet shape and a fiber shape, and particularly preferably a particle shape or a spherical shape. The water absorbing agent may be a granulated product.
　本発明の吸水剤は、水や各種水溶液、尿や血液等の水溶液の吸収用に用いられ、該吸水剤に含まれる全成分中、主成分として、吸水性樹脂の樹脂純分を、吸水剤１００質量部に対して、通常７０質量％（質量％）以上１００質量％以下、より好ましくは８０質量％以上１００質量％以下、さらに好ましくは９０質量％以上１００質量％以下含むものをいう。 The water-absorbing agent of the present invention is used for absorption of water, various aqueous solutions, aqueous solutions such as urine and blood, and the pure component of the water-absorbing resin is used as the main component in all the components contained in the water-absorbing agent. The content is usually 70% by mass (% by mass) or more and 100% by mass or less, more preferably 80% by mass or more and 100% by mass or less, and still more preferably 90% by mass or more and 100% by mass or less with respect to 100 parts by mass.
　固形分が上記範囲よりも小さな値となってしまうと、流動性が悪くなり製造し支障をきたすばかりか、吸水性樹脂が粉砕できなくなったり、特定の粒度分布に制御できなくなったりしてしまうおそれがある。 If the solid content becomes a value smaller than the above range, the fluidity may deteriorate and the production may be hindered, or the water absorbent resin may not be pulverized or controlled to a specific particle size distribution. There is.
　以下、本実施形態の吸水剤の特性について説明する。 Hereinafter, the characteristics of the water-absorbing agent of this embodiment will be described.
　＜遠心分離機保持容量（ＣＲＣ）＞
　本発明の吸水剤の、０．９０質量％塩化ナトリウム水溶液に対する無加圧下吸収倍率（ＣＲＣ／Centrifuge Retention Capacity）の３０分における値の下限は、好ましくは１０ｇ／ｇ、より好ましくは１５ｇ／ｇ、さらに好ましくは２０ｇ／ｇである。また、本発明の吸水剤の、無加圧下吸収倍率（ＣＲＣ）の３０分における値の上限は、好ましくは５０ｇ／ｇ、より好ましくは４０ｇ／ｇ、さらに好ましくは３５ｇ／ｇである。吸収倍率がこの範囲から外れると、吸水剤をおむつに使用した場合、高物性を示さない場合がある。そのために、表面架橋処理前の吸水性樹脂の無加圧下吸収倍率（ＣＲＣ）は、好ましくは１０～６０ｇ／ｇ、より好ましくは２５～４０ｇ／ｇの範囲に制御する。 <Centrifuge retention capacity (CRC)>
The lower limit of the value in 30 minutes of the absorption capacity under non-pressurization (CRC / Centrifuge Retention Capacity) of the water-absorbing agent of the present invention with respect to a 0.90 mass% sodium chloride aqueous solution is preferably 10 g / g, more preferably 15 g / g, More preferably, it is 20 g / g. Moreover, the upper limit of the value in 30 minutes of the absorption capacity | capacitance (CRC) under no pressure of the water absorbing agent of this invention becomes like this. Preferably it is 50 g / g, More preferably, it is 40 g / g, More preferably, it is 35 g / g. If the absorption ratio is out of this range, high physical properties may not be exhibited when the water absorbing agent is used in a diaper. For this purpose, the absorption capacity without load (CRC) of the water-absorbent resin before the surface crosslinking treatment is preferably controlled in the range of 10 to 60 g / g, more preferably 25 to 40 g / g.
　また、本発明では、上記表面架橋によってその吸収倍率が低下する。しかし、好ましくは表面架橋前の吸収倍率の９５～５０％、より好ましくは９０～６０％で低下を抑えることが必要である。なお、吸収倍率の低下は架橋剤の種類や量、反応温度や時間等で適宜調整すればよい。 Further, in the present invention, the absorption capacity is reduced by the surface cross-linking. However, it is necessary to suppress the decrease preferably at 95 to 50%, more preferably 90 to 60% of the absorption ratio before surface crosslinking. Note that the reduction in the absorption capacity may be appropriately adjusted depending on the type and amount of the crosslinking agent, reaction temperature, time, and the like.
　＜食塩水流れ誘導性（ＳＦＣ）＞
　生理食塩水流れ誘導性は、吸水剤の膨潤時の液透過性を示す値であり、その値が大きいほど高い液透過性を有することを示している。 <Saline flow conductivity (SFC)>
The physiological saline flow inductivity is a value indicating the liquid permeability when the water-absorbing agent swells, and indicates that the larger the value, the higher the liquid permeability.
　本発明で得られる吸水剤は、好ましくは１０（１０－７・ｃｍ３・ｓ・ｇ－１）以上、より好ましくは３０（１０－７・ｃｍ３・ｓ・ｇ－１）以上、さらに好ましくは５０（１０－７・ｃｍ３・ｓ・ｇ－１）以上、特に好ましくは８０（１０－７・ｃｍ３・ｓ・ｇ－１）以上の生理食塩水流れ誘導性（ＳＦＣ／Saline Flow Conductivity）を有し、食塩水流れ誘導性の値は特に限定されるものではないが、上限は、３０００（１０－７・ｃｍ３・ｓ・ｇ－１）程度であればよい。 The water-absorbing agent obtained in the present invention is preferably 10 (10 −7 · cm 3 · s · g −1 ) or more, more preferably 30 (10 −7 · cm 3 · s · g −1 ) or more, further preferably Is more than 50 (10 −7 · cm 3 · s · g −1 ), particularly preferably 80 (10 −7 · cm 3 · s · g −1 ) or more, saline flow conductivity (SFC / Saline Flow Conductivity) The value of the saline flow conductivity is not particularly limited, but the upper limit may be about 3000 (10 −7 · cm 3 · s · g −1 ).
　＜加圧下吸収倍率（ＡＡＰ）＞
　本発明の吸水剤の無加圧下吸収倍率ＡＡＰ（Ａｂｓｏｒｂｅｎｃｙ　ａｇａｉｎｓｔ　Ｐｒｅｓｕｕｒｅ）は、８（ｇ／ｇ）以上、好ましくは１６（ｇ／ｇ）以上であり、より好ましくは２０（ｇ／ｇ）以上であり、さらに好ましくは２２（ｇ／ｇ）以上であり、最も好ましくは２４（ｇ／ｇ）以上である。 <Absorption capacity under pressure (AAP)>
Absorption capacity AAP (Absorbency Against Pure) of the water-absorbing agent of the present invention is 8 (g / g) or more, preferably 16 (g / g) or more, more preferably 20 (g / g) or more. Yes, more preferably 22 (g / g) or more, and most preferably 24 (g / g) or more.
　＜水可溶分（可溶分）量＞
　本発明の吸水剤の水可溶分量が好ましくは０～３５質量％以下、より好ましくは２５質量％以下り、さらに好ましくは１５質量％以下、特に好ましくは１０質量％以下である。水可溶分量が３５質量％を超える場合、ゲル強度が弱く、通液性に劣ったものとなることがある。また、オムツ中で長時間使用した際に、吸収倍率（ＣＲＣやＡＡＰなど）が経時的に低下することがある。 <Amount of water soluble component (soluble component)>
The water-soluble content of the water-absorbing agent of the present invention is preferably 0 to 35% by mass or less, more preferably 25% by mass or less, still more preferably 15% by mass or less, and particularly preferably 10% by mass or less. When the water-soluble content exceeds 35% by mass, the gel strength is weak and the liquid permeability may be inferior. In addition, when used for a long time in a diaper, the absorption capacity (CRC, AAP, etc.) may decrease over time.
　＜固形分＞
　本発明の吸水剤は、吸水剤１００質量部に対する固形分が、好ましくは７０質量部以上、より好ましくは８０質量部以上、特に好ましくは９０質量部以上を示す。 <Solid content>
In the water-absorbing agent of the present invention, the solid content with respect to 100 parts by mass of the water-absorbing agent is preferably 70 parts by mass or more, more preferably 80 parts by mass or more, and particularly preferably 90 parts by mass or more.
　＜吸水剤の質量平均粒子径（Ｄ５０）等＞
　本発明の吸水剤は、吸水剤の質量に対して、好ましくは１５０μｍ以上８５０μｍ未満の粒子径の粒子が９０重量％以上（上限１００％）含まれており、より好ましくは１５０μｍ以上８５０μｍ未満の粒子が９５重量％以上含まれており、さらに好ましくは１５０μｍ以上８５０μｍ未満の粒子が９８重量％以上含まれている。なお、上記造粒を行う場合には、吸水剤が上記の質量平均粒子径となるように調整することが好ましい。そのために、表面架橋処理前の吸水性樹脂の質量平均粒子径（Ｄ５０）は、１５０μｍ以上、８５０μｍ未満の範囲に制御することが好ましい。 <Mass average particle diameter (D50) etc. of water absorbing agent>
The water-absorbing agent of the present invention preferably contains 90% by weight or more (upper limit of 100%) of particles having a particle size of 150 μm or more and less than 850 μm, more preferably 150 μm or more and less than 850 μm, based on the mass of the water-absorbing agent. Is contained in an amount of 95% by weight or more, and more preferably 98% by weight or more of particles of 150 μm or more and less than 850 μm. In addition, when performing the said granulation, it is preferable to adjust so that a water absorbing agent may become said mass mean particle diameter. Therefore, it is preferable to control the mass average particle diameter (D50) of the water-absorbent resin before the surface crosslinking treatment to a range of 150 μm or more and less than 850 μm.
　本発明の吸水剤は、不飽和単量体を重合して得られる架橋構造を有する吸水性樹脂を主成分とする吸水剤であって、上記吸水剤の粒度は、８５０μｍ未満で１５０μｍ以上の粒子が全体の９０重量％以上（上限は１００重量％）である。 The water-absorbing agent of the present invention is a water-absorbing agent mainly composed of a water-absorbing resin having a crosslinked structure obtained by polymerizing an unsaturated monomer, and the water-absorbing agent has a particle size of less than 850 μm and 150 μm or more. Is 90% by weight or more of the whole (the upper limit is 100% by weight).
　本発明に係るポリシロキサンおよび吸水性樹脂の重量％は、上記吸水剤において、好ましくは８０重量％以上（上限は１００重量％以下）、より好ましくは９０重量％以上、さらに好ましくは９５重量％以上、特に好ましくは９８重量％以上である。上記吸水剤の粒度は、好ましくは２５０μｍ以上の粒子が全体の７０重量％以上（上限１００重量％）である。 The weight percent of the polysiloxane and the water-absorbing resin according to the present invention is preferably 80% by weight or more (upper limit is 100% by weight or less), more preferably 90% by weight or more, and still more preferably 95% by weight or more in the water-absorbing agent. Particularly preferred is 98% by weight or more. The particle size of the water-absorbing agent is preferably 70% by weight or more (upper limit 100% by weight) of particles having a size of 250 μm or more.
　本発明における吸水性樹脂および本発明で得られる吸水剤は、本発明を達成する上で特定粒度に調整され、好ましくは、８５０μｍ未満で１５０μｍ以上の粒子（ふるい分級で規定：ＪＩＳ　Ｚ８８０１－１：２０００）が全体の９０重量％以上であり、より好ましくは、８５０μｍ未満で１５０μｍ以上の粒子が全体の９５重量％以上であり、さらに好ましくは８５０μｍ未満で１５０μｍ以上の粒子が全体の９８重量％以上である。また、３００μｍ以上の粒子が全体の６０重量％以上であることが好ましい。 The water-absorbing resin in the present invention and the water-absorbing agent obtained in the present invention are adjusted to a specific particle size in order to achieve the present invention, and preferably particles having a particle size of less than 850 μm and 150 μm or more (specified by sieve classification: JIS Z8801-1: 2000) is 90% by weight or more of the whole, more preferably, particles less than 850 μm and 150 μm or more are 95% by weight or more, more preferably less than 850 μm and particles of 150 μm or more are 98% by weight or more. It is. Moreover, it is preferable that the particle | grains of 300 micrometers or more are 60 weight% or more of the whole.
　なお、ここで全体とは、吸水性樹脂または吸水剤の全体を意味する。 In addition, the whole here means the whole water-absorbing resin or water-absorbing agent.
　また、２５０μｍ以上の粒子が、好ましくは７０重量％以上（上限１００重量％）、より好ましくは７５重量％以上とされる。また、吸水性樹脂あるいは吸水剤の重量平均粒子径（Ｄ５０）は、好ましくは２００～６００μｍ、より好ましくは３００～６００μｍ、さらに好ましくは３００～５００μｍ、特に好ましくは３５０～４５０μｍとされる。吸水性樹脂ないし吸水剤の粒子径は必要により造粒などで調整してもよい。 Further, the particle size of 250 μm or more is preferably 70% by weight or more (upper limit 100% by weight), more preferably 75% by weight or more. The weight average particle diameter (D50) of the water absorbent resin or water absorbent is preferably 200 to 600 μm, more preferably 300 to 600 μm, still more preferably 300 to 500 μm, particularly preferably 350 to 450 μm. If necessary, the particle diameter of the water-absorbing resin or water-absorbing agent may be adjusted by granulation.
　このようにして得られた吸水性樹脂や吸水剤の粒子形状は、球状、破砕状、不定形状等特に限定されるものではないが、粉砕工程を経て得られた不定形破砕状のものが好ましく使用できる。さらに、その嵩比重（ＪＩＳ　Ｋ－３３６２：１９９８で規定）は、通液性と液吸い上げ特性のバランスから、好ましくは０．４０～０．８０ｇ／ｍｌ、より好ましくは０．５０～０．７５ｇ／ｍｌ、さらに好ましくは０．６０～０．７３ｇ／ｍｌの範囲である。 The particle shape of the water-absorbing resin and water-absorbing agent thus obtained is not particularly limited, such as spherical, crushed, and irregular shapes, but is preferably an irregularly crushed one obtained through the pulverization step. Can be used. Furthermore, the bulk specific gravity (specified in JIS K-3362: 1998) is preferably 0.40 to 0.80 g / ml, more preferably 0.50 to 0.75 g, in terms of the balance between liquid permeability and liquid uptake characteristics. / Ml, more preferably in the range of 0.60 to 0.73 g / ml.
　粒子径の分布を表す対数標準偏差値σζは、０．１～０．６の範囲が好ましく、より好ましくは０．２～０．５、さらに好ましくは０．２５～０．４０、特に好ましくは０．２５～０．３８の範囲である。 The logarithmic standard deviation value σζ representing the particle size distribution is preferably in the range of 0.1 to 0.6, more preferably 0.2 to 0.5, still more preferably 0.25 to 0.40, and particularly preferably. It is in the range of 0.25 to 0.38.
　１５０μｍ未満の粒子（微粉）が１０重量％を超える場合には、吸水時に血液や尿等の吸収体への液の拡散性が阻害されること、吸収体としての使用時に空気との接触面積が増加するので吸水剤が可溶化しやすくなること、さらには吸湿時の流動性も悪くなること、吸水剤やオムツ等衛生材料製造時における作業中の粉塵発生による作業環境の劣悪化、幅広い粒度分布を有することによる偏析の増大等多くの問題が発生することとなり好ましくない。また対数標準偏差が０．２５未満の場合、かさ密度が低下する場合がある。特に、粉体の流動性が向上する本発明の吸水剤においては、質量平均粒子径の分布が広い場合や微粉が多い場合には、ホッパーや袋中において偏析が顕著になるために、おむつ等に組み込む際に品質のばらつきを引き起こしやすくなる。８５０μｍ以上の粒子が１０重量％を超える場合は、吸水剤の吸水速度が遅くなり、また、吸収物品に使用した際に吸収体の肌触りが悪く、異物感が現れ、使用者に対して不快感を与えるので好ましくない。よって、本発明の好ましい範囲に質量平均粒子径を調整することにより、流動性、かさ密度に優れ、吸水性能が低下せず、かつ偏析等の問題がない吸水剤を得ることが可能となる。 When particles (fine powder) of less than 150 μm exceed 10% by weight, the diffusibility of the liquid to the absorber such as blood and urine is inhibited during water absorption, and the contact area with the air when used as an absorber. The water absorption agent is easily solubilized because it increases, the fluidity during moisture absorption also deteriorates, the working environment deteriorates due to the generation of dust during the production of hygienic materials such as water absorbents and diapers, and a wide particle size distribution Many problems such as an increase in segregation due to the presence of this are undesirable. Further, when the logarithmic standard deviation is less than 0.25, the bulk density may decrease. In particular, in the water-absorbing agent of the present invention that improves the fluidity of the powder, when the mass average particle size distribution is wide or there are many fine powders, segregation becomes prominent in the hopper or bag, so that diapers, etc. It becomes easy to cause a variation in quality when it is incorporated into the product. When the particle size of 850 μm or more exceeds 10% by weight, the water absorption rate of the water-absorbing agent is slow, and when used in an absorbent article, the absorbent body feels bad, and a foreign body sensation appears, causing discomfort to the user. Is not preferable. Therefore, by adjusting the mass average particle diameter within the preferable range of the present invention, it is possible to obtain a water absorbing agent that is excellent in fluidity and bulk density, does not deteriorate water absorbing performance, and has no problems such as segregation.
　吸水剤の質量平均粒子径は、目的やその必要に応じて不溶性微粒子や親水性溶媒、好ましくは水を添加混合してさらに造粒して調整してもよい。 The mass average particle diameter of the water-absorbing agent may be adjusted by adding and mixing insoluble fine particles or a hydrophilic solvent, preferably water, depending on the purpose and necessity, and further granulating.
　質量平均粒子径の調整は、逆相縣濁重合のように粒子状で分散重合及び分散乾燥させて調整してもよいが、水溶液重合の場合等、通常は乾燥後に粉砕及び分級されて、必要により微粉を造粒等によりリサイクルさせることで、特定の質量平均粒子径に調整される。 The adjustment of the mass average particle diameter may be adjusted by dispersion polymerization and dispersion drying in the form of particles as in reverse phase suspension polymerization, but in the case of aqueous solution polymerization, etc., it is usually necessary to be ground and classified after drying. The fine powder is recycled by granulation or the like to adjust to a specific mass average particle size.
　＜耐熱性＞
　本発明に係る吸水剤の耐熱性は、ポリシロキサン構造を含んでおり、耐熱性に優れる。吸水剤の耐熱性評価は、得られた吸水剤に着色が生じたか否かにて目視にて評価を行う。吸水剤が耐熱性を有する場合、通常、ポリマーの色である白色が観測される。この場合、製造工程において吸水剤に劣化は生じていないと判断できる。 <Heat resistance>
The heat resistance of the water absorbing agent according to the present invention includes a polysiloxane structure and is excellent in heat resistance. The heat resistance of the water-absorbing agent is evaluated visually based on whether or not the resulting water-absorbing agent is colored. When the water-absorbing agent has heat resistance, usually white, which is the color of the polymer, is observed. In this case, it can be determined that the water absorbing agent has not deteriorated in the manufacturing process.
　一方、吸水剤に黄色などが観測された場合、吸水剤は耐熱性を有さず、ポリマーに劣化が生じている可能性が高いと判断される。 On the other hand, if yellow or the like is observed in the water-absorbing agent, it is determined that the water-absorbing agent does not have heat resistance and the polymer is highly likely to be deteriorated.
　なお、吸水剤の耐熱性評価において、吸水剤の製造工程での温度は特に限定されず、あくまで、個々の吸水剤の製造工程に係る温度にて、吸水剤に着色が生じるか否かで耐熱性が観測される。 In the heat resistance evaluation of the water-absorbing agent, the temperature in the manufacturing process of the water-absorbing agent is not particularly limited, and the heat-resistance depends on whether the water-absorbing agent is colored at the temperature related to the manufacturing process of the individual water-absorbing agent. Sex is observed.
　（１４）吸収体および／または吸収性物品
　本発明の吸水剤は、吸水を目的とした用途に用いられ、吸収体や吸収性物品として広く使用されるが、特に、尿や血液等の体液を吸収するための衛生材料として好適に用いられる。本発明の吸収体や吸収性物品は、本発明の吸水剤を含んでなるものである。 (14) Absorber and / or Absorbent Article The water-absorbing agent of the present invention is used for applications intended to absorb water and is widely used as an absorber or absorbent article. In particular, body fluids such as urine and blood are used. It is suitably used as a sanitary material for absorption. The absorbent body and absorbent article of the present invention comprise the water-absorbing agent of the present invention.
　ここで、上記吸収体とは、吸水剤と親水性繊維とを主成分して成型された吸収材のことである。上記吸収体は、本発明の吸水剤と親水性繊維とを用いて、例えば、フィルム状、筒状、シート状に成型され、製造される。上記吸収体は、吸水剤と親水性繊維との合計質量に対する吸水剤の含有量（コア濃度）が、好ましくは２０～１００重量％、より好ましくは３０～１００重量％、さらに好ましくは４０～１００重量％の範囲である。上記吸収体は、吸水剤のコア濃度が高いほど、吸収体や紙おむつ等の作製時における吸水剤の吸収特性低下効果が顕著に表れてくるものとなる。 Here, the absorber is an absorbent material molded mainly with a water-absorbing agent and hydrophilic fibers. The said absorber is shape | molded and manufactured into a film form, a cylinder shape, and a sheet form, for example using the water absorbing agent and hydrophilic fiber of this invention. In the absorbent body, the water absorbent content (core concentration) with respect to the total mass of the water absorbent and the hydrophilic fibers is preferably 20 to 100% by weight, more preferably 30 to 100% by weight, and still more preferably 40 to 100%. It is in the range of wt%. In the absorbent body, as the core concentration of the water-absorbing agent is higher, the effect of lowering the absorption characteristics of the water-absorbing agent at the time of producing the absorbent body, a paper diaper or the like becomes more prominent.
　上記吸収性物品とは、上記吸収体、液透過性を有する表面シート、及び液不透過性を有する背面シートを備える吸収性物品である。上記吸収性物品の製造方法は、まず、例えば繊維材料と吸水剤とをブレンドないしサンドイッチすることで吸収体（吸収コア）を作製する。次に、上記吸収体を、液透過性を有する表面シートと液不透過性を有する背面シートとでサンドイッチして、必要に応じて、弾性部材、拡散層、粘着テープ等を装備することで、吸収性物品、特に大人用紙オムツや生理用ナプキンとされる。上記吸収体は、密度０．０６～０．５０ｇ／ｃｃ、坪量０．０１～０．２０ｇ／ｃｍ２の範囲に圧縮成型されて用いられる。なお、用いられる繊維材料としては、親水性繊維、例えば粉砕された木材パルプ、コットンリンターや架橋セルロース繊維、レーヨン、綿、羊毛、アセテート、ビニロン等を例示できる。好ましくは、それらをエアレイドしたものである。 The said absorbent article is an absorbent article provided with the said absorber, the surface sheet which has liquid permeability, and the back sheet | seat which has liquid impermeability. The manufacturing method of the said absorbent article first produces an absorber (absorption core) by blending or sandwiching a fiber material and a water absorbing agent, for example. Next, the absorbent body is sandwiched between a liquid-permeable top sheet and a liquid-impermeable back sheet, and if necessary, equipped with an elastic member, a diffusion layer, an adhesive tape, etc. Absorbent articles, especially adult paper diapers and sanitary napkins. The absorbent body is used by being compression-molded in a range of density 0.06 to 0.50 g / cc and basis weight 0.01 to 0.20 g / cm 2 . Examples of the fiber material used include hydrophilic fibers such as pulverized wood pulp, cotton linters and crosslinked cellulose fibers, rayon, cotton, wool, acetate, and vinylon. Preferably, they are airlaid.
　本発明の吸水性物品は、優れた吸収特性を示すものである。このような吸収性物品としては、具体的には、近年成長の著しい大人用紙オムツをはじめ、子供用オムツ、生理用ナプキン、いわゆる失禁パッド等の衛生材料等が挙げられる。ただし、それらに限定されるものではない。本発明の吸水性物品は、吸収性物品の中に存在する吸水剤の優れた吸収特性により、戻り量も少なく、ドライ感が著しく、装着している本人・介護の人々の負担を大きく低減することができる。 The water-absorbent article of the present invention exhibits excellent absorption characteristics. Specific examples of such absorbent articles include diapers for children, sanitary napkins, sanitary materials such as so-called incontinence pads, as well as adult paper diapers that have been growing rapidly in recent years. However, it is not limited to them. The water-absorbent article according to the present invention has a small amount of return due to the excellent absorption characteristics of the water-absorbing agent present in the absorbent article, has a remarkably dry feeling, and greatly reduces the burden on the wearer and the caregiver. be able to.
　なお、本発明は、上述した各実施形態に限定されるものではなく、請求項に示した範囲で種々の変更が可能であり、異なる実施形態にそれぞれ開示された技術的手段を適宜組み合わせて得られる実施形態についても本発明の技術的範囲に含まれる。 The present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the claims, and the technical means disclosed in different embodiments can be appropriately combined. Such embodiments are also included in the technical scope of the present invention.
　以下に、実施例及び比較例によって本発明をより具体的に説明するが、本発明はこれらに限定されるものではない。また、実施例及び比較例において使用される電気機器は、全て１００Ｖ、６０Ｈｚの条件で使用した。さらに、特に指定がない限り２５℃±２℃、相対湿度５０％ＲＨの条件下で使用した。 Hereinafter, the present invention will be described more specifically with reference to Examples and Comparative Examples, but the present invention is not limited to these. Moreover, all the electric equipments used in Examples and Comparative Examples were used under the conditions of 100 V and 60 Hz. Further, unless otherwise specified, it was used under the conditions of 25 ° C. ± 2 ° C. and relative humidity 50% RH.
　本発明の請求の範囲や実施例に記載の諸物性は、以下の測定法に従って求めた。 The physical properties described in the claims and examples of the present invention were determined according to the following measurement methods.
　また、便宜上、「質量部」を単に「部」と、「リットル」を単に「Ｌ」と記すことがある。また、「質量％」を「ｗｔ％」と記すことがある。 For convenience, “parts by mass” may be simply referred to as “parts” and “liters” may be simply referred to as “L”. In addition, “mass%” may be described as “wt%”.
　＜遠心分離機保持容量（ＣＲＣ）＞
　遠心分離機保持容量（ＣＲＣ）は０．９０質量％食塩水に対する無加圧下で３０分の吸収倍率を示す。なお、ＣＲＣは、無加圧下吸収倍率と称されることもある。 <Centrifuge retention capacity (CRC)>
The centrifuge retention capacity (CRC) shows an absorption capacity of 30 minutes under no pressure with respect to 0.90 mass% saline. CRC is sometimes referred to as absorption capacity without pressure.
　吸水剤０．２００ｇを不織布製（南国パルプ工業（株）製、商品名：ヒートロンペーパー、型式：ＧＳＰ－２２）の袋（８５ｍｍ×６０ｍｍ）に均一に入れてヒートシールした後、室温で大過剰（通常５００ｍｌ程度）の０．９０質量％食塩水（塩化ナトリウム水溶液）中に浸漬した。３０分後に袋を引き上げ、遠心分離機（株式会社コクサン社製、遠心機：型式Ｈ－１２２）を用いてｅｄａｎａ　ＡＢＳＯＲＢＥＮＣＹ　II　４４１．１－９９に記載の遠心力（２５０Ｇ）で３分間水切りを行った後、袋の質量Ｗ１（ｇ）を測定した。また、同様の操作を、吸水剤を用いずに行い、その時の質量Ｗ０（ｇ）を測定した。そして、これらＷ１、Ｗ０から、次式に従って遠心分離機保持容量（ＣＲＣ）（ｇ／ｇ）を算出した。 0.200 g of the water-absorbing agent was uniformly put into a bag (85 mm × 60 mm) made of a nonwoven fabric (Nangoku Pulp Industries Co., Ltd., trade name: Heaton paper, model: GSP-22) and heat-sealed. It was immersed in an excess (usually about 500 ml) of 0.90% by mass saline (aqueous sodium chloride solution). After 30 minutes, the bag was pulled up and drained for 3 minutes with a centrifugal force (250 G) described in edana ABSORBENCY II 441.1-99 using a centrifuge (manufactured by Kokusan Co., Ltd., centrifuge: model H-122). After that, the mass W1 (g) of the bag was measured. Moreover, the same operation was performed without using a water absorbing agent, and the mass W0 (g) at that time was measured. The centrifuge retention capacity (CRC) (g / g) was calculated from these W1 and W0 according to the following formula.
　遠心分離機保持容量（ＣＲＣ）（ｇ／ｇ）
＝（Ｗ１（ｇ）－Ｗ０（ｇ））／（吸水剤の質量（ｇ））－１
　＜食塩水流れ誘導性（ＳＦＣ）＞
　食塩水流れ誘導性（ＳＦＣ）は吸水剤の膨潤時の液透過性を示す値である。ＳＦＣの値が大きいほど、吸水剤は、高い液透過性を有することとなる。本実施例においては、米国特許第５８４９４０５号明細書記載のＳＦＣ試験に準じて行った。図１は、ＳＦＣの測定装置２０を示す概略図である。 Centrifuge retention capacity (CRC) (g / g)
= (W1 (g) -W0 (g)) / (mass of water-absorbing agent (g))-1
<Saline flow conductivity (SFC)>
The saline flow conductivity (SFC) is a value indicating the liquid permeability when the water absorbing agent swells. The greater the SFC value, the higher the water-absorbing agent has liquid permeability. In this example, the test was conducted according to the SFC test described in US Pat. No. 5,849,405. FIG. 1 is a schematic diagram showing an SFC measurement apparatus 20.
　図１に示す測定装置２０において、タンク２１にはガラス管２２が挿入されており、ガラス管２２の下端は、０．６９質量％食塩水２３をセル３１中のゲル３４の底部から、５ｃｍ上の高さに維持できるように配置されている。また、タンク２１中の０．６９質量％食塩水２３は、コック付きＬ字管２４を通じてセル３１へ供給されるよう構成されている。セル３１の下には、透過した液を捕集する捕集容器３８が配置されており、捕集容器３８は上皿天秤３９の上に設置されている。セル３１の内径は６ｃｍであり、下部の底面にはＮｏ．４００ステンレス製金網（目開き３８μｍ）３２が設置されていた。ピストン３６の下部には液が透過するのに十分な穴３７があり、底部には吸水剤あるいはその膨潤ゲルが、穴３７へ入り込まないように透過性の良いガラスフィルター３５が取り付けてあった。セル３１は、セル３１を乗せるための台の上に置かれ、セル３１と接する台の面は、液の透過を妨げないステンレス製の金網３３の上に設置した。 In the measuring apparatus 20 shown in FIG. 1, a glass tube 22 is inserted into the tank 21, and the lower end of the glass tube 22 is 5 cm above the bottom of the gel 34 in the cell 31 with 0.69 mass% saline solution 23. It is arranged so that it can be maintained at a height. Further, the 0.69 mass% saline solution 23 in the tank 21 is configured to be supplied to the cell 31 through the L-shaped tube 24 with a cock. A collection container 38 that collects the permeated liquid is disposed below the cell 31, and the collection container 38 is installed on an upper pan balance 39. The inner diameter of the cell 31 is 6 cm. A 400 stainless steel wire mesh (aperture 38 μm) 32 was installed. At the bottom of the piston 36 there was a hole 37 sufficient for the liquid to permeate, and a glass filter 35 with good permeability was attached to the bottom so that the water-absorbing agent or its swollen gel would not enter the hole 37. The cell 31 was placed on a table on which the cell 31 was placed, and the surface of the table in contact with the cell 31 was installed on a stainless steel wire mesh 33 that did not hinder the permeation of the liquid.
　人工尿（１）は、塩化カルシウムの２水和物０．２５ｇ、塩化カリウム２．０ｇ、塩化マグネシウムの６水和物０．５０ｇ、硫酸ナトリウム２．０ｇ、りん酸２水素アンモニウム０．８５ｇ、りん酸水素２アンモニウム０．１５ｇ、および、純水９９４．２５ｇを加えたものを用いた。 Artificial urine (1) is calcium chloride dihydrate 0.25 g, potassium chloride 2.0 g, magnesium chloride hexahydrate 0.50 g, sodium sulfate 2.0 g, ammonium dihydrogen phosphate 0.85 g, What added 0.15 g of hydrogen ammonium diphosphate and 994.25 g of pure waters was used.
　図１に示す測定装置２０を用い、容器３０に均一に入れた吸水剤（０．９００ｇ）を人工尿（１）中で２．０７ｋＰａ（０．３ｐｓi）の加圧下、６０分間膨潤させゲル３４とした。その後、ゲル３４のゲル層の高さを記録し、次に２．０７ｋＰａ（０．３ｐｓi）の加圧下、０．６９質量％の食塩水２３を、一定の静水圧でタンク２１から膨潤したゲル層を通液させた。このＳＦＣ試験は室温（２０℃以上２５℃以下）で行った。試験ではコンピューターと天秤とを用い、時間の関数として、２０秒間隔でゲル層を透過する液体量を１０分間記録した。膨潤したゲル３４（の主に粒子間）を透過する流速Ｆｓ（Ｔ）は増加質量（ｇ）を増加時間（ｓ）で割ることによりｇ／ｓの単位で決定した。一定の静水圧と安定した流速が得られた時間をＴｓとし、Ｔｓと１０分間の間に得たデータだけを流速計算に使用して、Ｔｓと１０分間の間に得た流速を使用してＦｓ（Ｔ＝０）の値、つまりゲル層を通る最初の流速を計算した。Ｆｓ（Ｔ＝０）はＦｓ（Ｔ）対時間の最小２乗法の結果をＴ＝０に外挿することにより計算した。 Using the measuring apparatus 20 shown in FIG. 1, the water absorbing agent (0.900 g) uniformly placed in the container 30 is swollen for 60 minutes in an artificial urine (1) under a pressure of 2.07 kPa (0.3 psi) for 60 minutes. It was. Thereafter, the height of the gel layer of the gel 34 is recorded, and then a 0.69 mass% saline solution 23 is swollen from the tank 21 at a constant hydrostatic pressure under a pressure of 2.07 kPa (0.3 psi). The layers were passed through. This SFC test was performed at room temperature (20 ° C. or more and 25 ° C. or less). In the test, a computer and a balance were used, and the amount of liquid that permeated the gel layer was recorded for 10 minutes at intervals of 20 seconds as a function of time. The flow rate Fs (T) permeating the swollen gel 34 (mainly between the particles) was determined in units of g / s by dividing the increased mass (g) by the increased time (s). Let Ts be the time at which a constant hydrostatic pressure and a stable flow rate were obtained, use only the data obtained between Ts and 10 minutes for the flow rate calculation, and use the flow rate obtained between Ts and 10 minutes. The value of Fs (T = 0), ie the initial flow rate through the gel layer, was calculated. Fs (T = 0) was calculated by extrapolating the result of the least squares method of Fs (T) versus time to T = 0.
　食塩水流れ誘導性（ＳＦＣ）
＝（Ｆｓ（ｔ＝０）×Ｌ０）／（ρ×Ａ×ΔＰ）
＝（Ｆｓ（ｔ＝０）×Ｌ０）／１３９５０６
　ここで、Ｆｓ（ｔ＝０）：ｇ／ｓで表した流速、Ｌ０：ｃｍで表したゲル層の高さ、ρ：ＮａＣｌ溶液の密度（１．００３ｇ／ｃｍ３）、Ａ：セル３１中のゲル層上側の面積（２８．２７ｃｍ２）、ΔＰ：ゲル層にかかる静水圧（４９２０ｄｙｎｅ／ｃｍ２）およびＳＦＣ値の単位は（１０－７・ｃｍ３・ｓ・ｇ－１）である。
＜加圧下吸収倍率（ＡＡＰ）＞
　国際公開ＷＯ２００６／１０９８４４および国際出願ＷＯ２００７／ＪＰ／５６５２７号を参照し、０．９％塩化ナトリウム水溶液に対する加圧下（荷重下）の吸収倍率を測定した。 Saline flow conductivity (SFC)
= (Fs (t = 0) × L0) / (ρ × A × ΔP)
= (Fs (t = 0) × L0) / 139506
Here, Fs (t = 0): flow rate expressed in g / s, gel layer height expressed in L0: cm, ρ: density of NaCl solution (1.003 g / cm 3 ), A: in cell 31 The unit of the upper surface area of the gel layer (28.27 cm 2 ), ΔP: hydrostatic pressure applied to the gel layer (4920 dyne / cm 2 ), and SFC value is (10 −7 · cm 3 · s · g −1 ).
<Absorption capacity under pressure (AAP)>
With reference to International Publication WO2006 / 109844 and International Application WO2007 / JP / 56527, the absorption capacity under pressure (under load) for a 0.9% sodium chloride aqueous solution was measured.
　図２に示す測定装置１０を用い、内径６０ｍｍのプラスチックの支持円筒１００の底に、ステンレス製４００メッシュの金網１０１（目の大きさ３８μｍ）を融着させ、該網上に０．９００ｇの吸水性樹脂１０２を均一に散布し、その上に、吸水性樹脂１０２に対して１．９ｋＰａ（０．３ｐｓｉ）または４．８ｋＰａ（０．７ｐｓｉ）の荷重を均一に加えることができるよう調整された、外径が６０ｍｍよりわずかに小さく支持円筒との隙間が生じず、かつ上下の動きが妨げられないピストン１０３と荷重１０４とをこの順に載置し、この測定装置一式の質量Ｗ３（ｇ）を測定した。 Using a measuring apparatus 10 shown in FIG. 2, a stainless steel 400 mesh wire mesh 101 (mesh size 38 μm) is fused to the bottom of a plastic support cylinder 100 having an inner diameter of 60 mm, and 0.900 g of water absorption is placed on the mesh. It was adjusted so that a load of 1.9 kPa (0.3 psi) or 4.8 kPa (0.7 psi) could be uniformly applied to the water-absorbent resin 102. The piston 103 and the load 104, which have an outer diameter slightly smaller than 60 mm and do not cause a gap with the support cylinder and do not hinder vertical movement, are placed in this order, and a mass W3 (g) of this measuring device set is set. It was measured.
　直径１５０ｍｍのペトリ皿１０５の内側に直径９０ｍｍのガラスフィルター１０６（株式会社相互理化学硝子製作所社製、細孔直径：１００～１２０μｍ）を置き、生理食塩水１０８（２０℃～２５℃）をガラスフィルターの上面と同じレベルになるように加えた。その上に、直径９０ｍｍの濾紙１０７（ＡＤＶＡＮＴＥＣ東洋株式会社、品名：（ＪＩＳ　Ｐ　３８０１、Ｎｏ．２）、厚さ０．２６ｍｍ、保留粒子径５μｍ）を１枚載せ、表面が全て濡れるようにし、かつ過剰の液を除いた。 A glass filter 106 having a diameter of 90 mm (manufactured by Mutual Riken Glass Co., Ltd., pore diameter: 100 to 120 μm) is placed inside a petri dish 105 having a diameter of 150 mm, and physiological saline 108 (20 ° C. to 25 ° C.) is placed in the glass filter. It was added so as to be the same level as the top surface. On top of that, a sheet of filter paper 107 having a diameter of 90 mm (ADVANTEC Toyo Co., Ltd., product name: (JIS P 3801, No. 2), thickness 0.26 mm, retention particle diameter 5 μm) was placed so that the entire surface was wetted. Excess liquid was removed.
　上記測定装置一式を前記湿った濾紙上に載せ、液を荷重下で吸収させた。１時間後、測定装置一式を持ち上げ、その質量Ｗ４（ｇ）を測定した。そして、Ｗ３、Ｗ４から、下記の式に従って圧力に対する加圧下吸収倍率（ｇ／ｇ）を算出した。 The above measuring device set was placed on the wet filter paper, and the liquid was absorbed under load. After 1 hour, the measuring device set was lifted and its mass W4 (g) was measured. And the absorption capacity | capacitance under pressure with respect to a pressure (g / g) was computed from W3 and W4 according to the following formula.
　式２：ＡＡＰ＝（Ｗ４－Ｗ３）／０．９
　＜水可溶分（水可溶成分）量＞
　２５０ｍｌ容量の蓋付きプラスチック容器に０．９０質量％食塩水１８４．３ｇをはかり取り、その水溶液中に吸水剤１．００ｇを加え１６時間、スターラーを回転させ攪拌することにより樹脂中の可溶分を抽出した。この抽出液を濾紙１枚（ＡＤＶＡＮＴＥＣ東洋株式会社、品名：（ＪIＳ　Ｐ　３８０１、Ｎｏ．２）、厚さ０．２６ｍｍ、保留粒子径５μｍ）を用いて濾過することにより得られた濾液の５０．０ｇを測り取り測定溶液とした。 Formula 2: AAP = (W4-W3) /0.9
<Amount of water-soluble component (water-soluble component)>
Weigh out 184.3 g of 0.90 mass% saline in a plastic container with a capacity of 250 ml, add 1.00 g of water-absorbing agent to the aqueous solution, and rotate and stir the stirrer for 16 hours to dissolve the soluble content in the resin. Extracted. Filtration of this extract using 1 sheet of filter paper (ADVANTEC Toyo Co., Ltd., product name: (JISP 3801, No. 2), thickness 0.26 mm, retained particle diameter 5 μm) gave 50. 0 g was measured and used as a measurement solution.
　はじめに０．９０質量％食塩水だけを、まず、０．１ＮのＮａＯＨ水溶液でｐＨ１０まで滴定を行い、その後、０．１ＮのＨＣｌ水溶液でｐＨ２．７まで滴定して空滴定量（［ｂＮａＯＨ］ｍｌ、［ｂＨＣｌ］ｍｌ）を得た。 First, only 0.90% by mass saline is titrated with 0.1N NaOH aqueous solution to pH 10, and then titrated with 0.1N HCl aqueous solution to pH 2.7 to perform empty titration ([bNaOH] ml). [BHCl] ml).
　同様の滴定操作を測定溶液についても行うことにより滴定量（［ＮａＯＨ］ｍｌ、［ＨＣｌ］ｍｌ）を求めた。 A titration ([NaOH] ml, [HCl] ml) was determined by performing the same titration operation on the measurement solution.
　例えば既知量のアクリル酸とそのナトリウム塩が主成分の吸水性樹脂または吸水剤の場合、そのモノマーの平均分子量と上記操作により得られた滴定量をもとに、吸水性樹脂または吸水剤中の可溶分量を以下の計算式により算出することができる。未知量の場合は滴定により求めた中和率を用いてモノマーの平均分子量を算出する。 For example, in the case of a water-absorbing resin or water-absorbing agent whose main component is a known amount of acrylic acid and its sodium salt, based on the average molecular weight of the monomer and the titration amount obtained by the above operation, The soluble content can be calculated by the following formula. In the case of an unknown amount, the average molecular weight of the monomer is calculated using the neutralization rate obtained by titration.
　可溶分（質量％）＝０．１×（平均分子量）×１８４．３×１００×（［ＨＣｌ］－［ｂＨＣｌ］）／１０００／１．０／５０．０
　中和率（ｍｏｌ％）＝（１－（［ＮａＯＨ］－［ｂＮａＯＨ］）／（［ＨＣｌ］－［ｂＨＣｌ］））×１００
　＜粒度＞
　ＷＯ２００４／０６９４０４号に準じて、吸水性樹脂（または吸水剤）を８５０μｍ、７１０μｍ、６００μｍ、５００μｍ、４２５μｍ、３００μｍ、２１２μｍ、１５０μｍ、１０６μｍ、４５μｍのＪＩＳ標準ふるい（ＪＩＳ　Ｚ８８０１－１（２０００））ないしその相当ふるいで篩い分けし、残留百分率Ｒを対数確率紙にプロットした。これにより、Ｒ＝５０重量％に相当する粒径を質量平均粒子径（Ｄ５０）として読み取った。また、対数標準偏差（σζ）は下記の式１で表され、σζの値が小さいほど粒度分布が狭いことを意味する。 Soluble content (mass%) = 0.1 × (average molecular weight) × 184.3 × 100 × ([HCl] − [bHCl]) / 1000 / 1.0 / 50.0
Neutralization rate (mol%) = (1 − ([NaOH] − [bNaOH]) / ([HCl] − [bHCl])) × 100
<Granularity>
According to WO 2004/066944, a water-absorbing resin (or water-absorbing agent) is used in a JIS standard sieve (JIS Z8801-1 (2000)) of 850 μm, 710 μm, 600 μm, 500 μm, 425 μm, 300 μm, 212 μm, 150 μm, 106 μm, 45 μm. Sieving with the corresponding sieve, the residual percentage R was plotted on log-probability paper. Thereby, the particle size corresponding to R = 50% by weight was read as the mass average particle size (D50). Further, the logarithmic standard deviation (σζ) is expressed by the following formula 1, and the smaller the value of σζ, the narrower the particle size distribution.
　式１：σζ　＝　０．５　×　ｌｎ（Ｘ２／Ｘ１）
　（Ｘ１はＲ＝８４．１％、Ｘ２は１５．９％に相当するそれぞれの粒径）
　＜吸水剤の固形分＞
　吸水剤において、１８０℃で揮発しない成分が占める割合を表す。含水率との関係は以下のようになる。 Formula 1: σζ = 0.5 × ln (X2 / X1)
(X1 is R = 84.1%, X2 is a particle size corresponding to 15.9%)
<Solid content of water-absorbing agent>
In the water-absorbing agent, the ratio of components that do not volatilize at 180 ° C. The relationship with the moisture content is as follows.
　固形分（質量％）＝１００－含水率（質量％）
　固形分の測定方法は、以下のように行った。 Solid content (mass%) = 100-moisture content (mass%)
The measurement method of solid content was performed as follows.
　底面の直径が約５ｃｍのアルミカップ（質量Ｗ０ ）に、約１ｇの吸水性樹脂を量り取り（質量Ｗ１ ）、１８０℃の無風乾燥機中において３時間静置し、乾燥させる。乾燥後のアルミカップ＋吸水性樹脂の質量（Ｗ２ ）を測定し、以下の式より固形分を求めた。 Measure about 1 g of water-absorbent resin (mass W1) in an aluminum cup (mass W0) with a bottom diameter of about 5 cm, and let stand in a windless dryer at 180 ° C. for 3 hours to dry. The mass (W2) of the dried aluminum cup + water absorbent resin was measured, and the solid content was determined from the following formula.
　固形分（質量％）＝（（Ｗ２ －Ｗ０ ）／Ｗ１ ）×１００
　＜ペイントシェーカーテスト＞
　ペイントシェーカーテスト（ＰＳ）とは、直径６ｃｍ、高さ１１ｃｍのガラス製容器に、直径６ｍｍのガラスビーズ１０ｇ、吸水性樹脂または吸水剤３０ｇを入れてペイントシェーカー（東洋製機製作所　製品Ｎｏ．４８８）に取り付け、８００ｃｙｃｌｅ／ｍiｎ（ＣＰＭ）で振盪するものであり、装置詳細は日本国公開特許公報「特開平９－２３５３７８号公報」に開示されている。 Solid content (mass%) = ((W2−W0) / W1) × 100
<Paint shaker test>
The paint shaker test (PS) is a paint shaker (Toyo Seisakusho Co., Ltd. Product No. 488) in which a glass container having a diameter of 6 cm and a height of 11 cm is filled with 10 g of glass beads having a diameter of 6 mm and a water-absorbing resin or a water-absorbing agent. The details of the apparatus are disclosed in Japanese Patent Publication “Japanese Patent Laid-Open No. 9-235378”, which is shaken at 800 cycle / min (CPM).
　振盪時間を３０分間としたものをペイントシェーカーテスト１、１０分間としたものをペイントシェーカーテスト２とする。浸透後、目開き２ｍｍのＪIＳ標準篩でガラスビーズを除去し、ダメージを与えられた吸水性樹脂または吸水剤が得られる。 The shaker time of 30 minutes is the paint shaker test 1 and the shake time is 10 minutes. After infiltration, the glass beads are removed with a JIS standard sieve having an opening of 2 mm, and a damaged water-absorbing resin or water-absorbing agent is obtained.
　〔参考例１〕
　濃度０．５Ｎの塩酸８３．６６ｇに３－アミノプロピルトリメトキシシラン５．００ｇを滴下し、室温で、２時間攪拌した。次に、反応混合物を６０℃の乾燥機に移し、水分を蒸発させた後、反応混合物を乾固させ１００℃にて１０～１６時間維持した。こうして得られたものを、ポリシロキサン（Ａ）とした。 [Reference Example 1]
To 83.66 g of 0.5N hydrochloric acid, 5.00 g of 3-aminopropyltrimethoxysilane was added dropwise and stirred at room temperature for 2 hours. Next, the reaction mixture was transferred to a dryer at 60 ° C. to evaporate the water, and then the reaction mixture was dried and maintained at 100 ° C. for 10 to 16 hours. The product thus obtained was designated as polysiloxane (A).
　〔参考例２〕
　イオン交換水１６．６７ｍＬ、メタノール３３．３３ｍＬ、トリエチルアミン０．３５ｍＬの混合溶液にポリシロキサン（Ａ）１．４６７ｇとアクリロイドクロリド０．０８１ｍＬとを滴下し、室温で、１０分間撹拌した。そして、この混合溶液に濃度５Ｎの塩酸１．０ｍＬを加えた後、アセトン２００ｍＬに滴下し、析出物を得た。この析出物を濾別し、５ｍＬのイオン交換水に溶解させた後、アセトン１５０ｍＬに滴下し、析出物を得た。この析出物を濾別し、室温で、減圧乾燥した。こうして得られたものをポリシロキサン（Ｂ）とした。 [Reference Example 2]
To a mixed solution of 16.67 mL of ion-exchanged water, 33.33 mL of methanol, and 0.35 mL of triethylamine, 1.467 g of polysiloxane (A) and 0.081 mL of acryloid chloride were added dropwise and stirred at room temperature for 10 minutes. And after adding 1.0 mL of 5N hydrochloric acid to this mixed solution, it was dripped at acetone 200mL, and the deposit was obtained. This precipitate was separated by filtration, dissolved in 5 mL of ion exchange water, and then added dropwise to 150 mL of acetone to obtain a precipitate. The precipitate was filtered off and dried under reduced pressure at room temperature. The product thus obtained was designated as polysiloxane (B).
　〔参考例３〕
　濃度０．５Ｎの塩酸８３．６６ｇに３－アミノプロピルトリメトキシシラン４．５０ｇとトリメトキシビニルシラン０．３７ｇとを滴下した。この溶液を室温で、２時間攪拌した。攪拌後の溶液を６０℃の乾燥機に移し、水分を蒸発、乾固させ、１００℃にて１０～１６時間維持し、生成物を得た。この生成物をポリシロキサン（Ｃ）とした。 [Reference Example 3]
To 83.66 g of 0.5N hydrochloric acid, 4.50 g of 3-aminopropyltrimethoxysilane and 0.37 g of trimethoxyvinylsilane were added dropwise. The solution was stirred at room temperature for 2 hours. The stirred solution was transferred to a dryer at 60 ° C. to evaporate and dry the water, and maintained at 100 ° C. for 10 to 16 hours to obtain a product. This product was designated as polysiloxane (C).
　＜ポリシロキサンの重合反応液への溶解性評価＞
　イオン交換水１００ｇにポリシロキサン（Ａ）１ｇを撹拌混合し、目視によりイオン交換水への溶解性を評価した。 <Evaluation of solubility of polysiloxane in polymerization reaction solution>
1 g of polysiloxane (A) was stirred and mixed with 100 g of ion-exchanged water, and the solubility in ion-exchanged water was evaluated visually.
　また、アクリル酸７．９ｇ、アクリル酸ナトリウム８４．０ｇ、イオン交換水７．２ｇの混合溶液にポリシロキサン（Ａ）の５質量％水溶液１ｇを滴下し、撹拌混合し、目視により重合反応液への溶解性を評価した。 In addition, 1 g of a 5% by mass aqueous solution of polysiloxane (A) was dropped into a mixed solution of 7.9 g of acrylic acid, 84.0 g of sodium acrylate, and 7.2 g of ion-exchanged water, mixed with stirring, and visually into the polymerization reaction solution. Was evaluated for solubility.
　さらに、ポリシロキサン（Ａ）の代わりにポリシロキサン（Ｂ）または（Ｃ）についても同様にイオン交換水への溶解性および重合反応液への溶解性の評価を行った。 Further, the polysiloxane (B) or (C) instead of the polysiloxane (A) was similarly evaluated for solubility in ion-exchanged water and solubility in a polymerization reaction solution.
　なお、比較のため、表１に示すアミノ変性シリコーンをポリシロキサン（Ａ）の代わりに用いて、同様の評価を行った。各々の結果を表１に示した。 For comparison, the same evaluation was performed using amino-modified silicone shown in Table 1 instead of polysiloxane (A). The results are shown in Table 1.
Figure JPOXMLDOC01-appb-T000001
 　表１から明らかなように、ポリシロキサン（Ａ）～（Ｃ）は、イオン交換水、重合反応液への溶解性を有している。
Figure JPOXMLDOC01-appb-T000001
 As is clear from Table 1, polysiloxanes (A) to (C) have solubility in ion-exchanged water and polymerization reaction solution.
　〔実施例１〕
　内径８０ｍｍ、容量１リットルのポリプロピレン製容器に、アクリル酸２５７．６ｇ、ポリシロキサン（Ａ）の２．０質量％水溶液１．５８ｇ、および、ジエチレントリアミン５酢酸・５ナトリウム水溶液の１．０質量％１．５８ｇを混合した溶液（Ａ）と、４８．５質量％水酸化ナトリウム水溶液２１５．２ｇと３２℃に調温したイオン交換水２０９．９ｇとを混合した溶液（Ｂ）を、マグネチックスターラーで攪拌しながら溶液（Ａ）に溶液（Ｂ）を開放系ですばやく加えて混合した。中和熱および溶解熱で液温が約１０２℃まで上昇した単量体水溶液が得られた。 [Example 1]
In a polypropylene container having an inner diameter of 80 mm and a capacity of 1 liter, acrylic acid 257.6 g, polysiloxane (A) 2.0 mass% aqueous solution 1.58 g, and diethylenetriaminepentaacetic acid-5 sodium aqueous solution 1.0 mass% 1 A solution (A) in which .58 g is mixed, a solution (B) in which 215.2 g of a 48.5% by mass aqueous sodium hydroxide solution and 209.9 g of ion-exchanged water adjusted to 32 ° C. are mixed with a magnetic stirrer. While stirring, the solution (B) was quickly added to the solution (A) in an open system and mixed. A monomer aqueous solution having a liquid temperature increased to about 102 ° C. by heat of neutralization and heat of dissolution was obtained.
　得られた単量体水溶液が９５℃になるまで待って、３質量％の過硫酸ナトリウム水溶液１４．３０ｇを加え、数秒攪拌した後に、ホットプレート（ＮＥＯ　ＨＯＴＰＬＡＴＥ　Ｈ１－１０００、（株）井内盛栄堂製）により表面温度を１００℃まで加熱された、内面にテフロン（登録商標）を貼り付けた底面２５０ｍｍ×２５０ｍｍのステンレス製バット型容器中に開放系で注いだ。ステンレス製バット型容器は、そのサイズが底面２５０ｍｍ×２５０ｍｍ、上面６４０ｍｍ×６４０ｍｍ、高さ５０ｍｍであり、中心断面が台形で、上面が開放されていた。 Wait until the resulting aqueous monomer solution reaches 95 ° C., add 14.30 g of a 3% by weight aqueous sodium persulfate solution, stir for several seconds, and then hot plate (NEO HOTPLATE H1-1000, Inoue Seieido Co., Ltd.). The product was poured into a stainless steel bat-shaped container having a bottom surface of 250 mm × 250 mm with Teflon (registered trademark) on the inner surface and heated to 100 ° C. by an open system. The stainless bat-shaped container had a bottom surface of 250 mm × 250 mm, a top surface of 640 mm × 640 mm, a height of 50 mm, a central cross section of a trapezoid, and an open top surface.
　単量体水溶液がバットに注がれて間もなく重合は開始した。水蒸気を発生して上下左右に膨張発泡しながら重合は進行し、その後、底面よりもやや大きなサイズにまで収縮した。この膨張収縮は約１分以内に終了し、４分間重合容器中に保持した後、含水重合体を取り出した。 Polymerization started soon after the monomer aqueous solution was poured into the vat. Polymerization proceeded while generating water vapor and expanding and foaming up and down, left and right, and then contracted to a size slightly larger than the bottom surface. This expansion and contraction was completed within about 1 minute, and after holding in the polymerization vessel for 4 minutes, the water-containing polymer was taken out.
　得られた含水重合体を、ダイス径９．５ｍｍのミートチョッパー（ＲＯＹＡＬ　ＭＥＡＴ　ＣＨＯＰＰＥＲ　ＶＲ４００Ｋ、飯塚工業株式会社製）により解砕し、細分化された含水重合体を得た。このときゲル投入量は約３４０ｇ／ｍｉｎ、ゲル投入と並行して脱イオン水を４８ｇ／ｍｉｎで添加しながら解砕を行った。 The obtained water-containing polymer was crushed with a meat chopper (ROYAL MEAT CHOPPER VR400K, manufactured by Iizuka Kogyo Co., Ltd.) having a die diameter of 9.5 mm to obtain a finely divided water-containing polymer. At this time, the amount of gel charged was about 340 g / min, and pulverization was performed while deionized water was added at 48 g / min in parallel with gel charging.
　解砕後のゲルの不揮発分量は５０～５５質量％であった。 The non-volatile content of the gel after pulverization was 50 to 55% by mass.
　この細分化された含水ゲル状架橋重合体を５０メッシュの金網上に広げ、１８０℃で３５分間熱風乾燥を行った。 The finely divided hydrogel crosslinked polymer was spread on a 50 mesh wire net and dried with hot air at 180 ° C. for 35 minutes.
　乾燥物をロールミルによって粉砕し、さらに目開き７１０μｍと目開き１７５μｍのＪＩＳ標準篩で分級することにより、吸水剤（１）を得た。 The dried product was pulverized with a roll mill, and further classified with a JIS standard sieve having an opening of 710 μm and an opening of 175 μm to obtain a water absorbing agent (1).
　〔実施例２〕
　実施例１のポリシロキサン（Ａ）の２．０質量％水溶液の使用量を１５７．５ｇに変更して同様の操作を行った。こうして、吸水剤（２）を得た。 [Example 2]
The same operation was carried out by changing the amount of the 2.0 mass% aqueous solution of polysiloxane (A) of Example 1 to 157.5 g. Thus, a water absorbing agent (2) was obtained.
　〔実施例３〕
　実施例１のポリシロキサン（Ａ）の２．０質量％水溶液の使用量を１．５８ｇに変更し、さらにポリエチレングリコールジアクリレート（分子量５２３）１．３１ｇ（０．０７ｍｏｌ％）を用いて、同様の操作を行った。こうして、吸水剤（３）を得た。 Example 3
The amount of the 2.0 mass% aqueous solution of the polysiloxane (A) in Example 1 was changed to 1.58 g, and 1.31 g (0.07 mol%) of polyethylene glycol diacrylate (molecular weight 523) was used in the same manner. Was performed. Thus, a water absorbing agent (3) was obtained.
　〔実施例４〕
　実施例１のポリシロキサン（Ａ）の２．０質量％水溶液の使用量を１５．７５ｇに変更し、さらにポリエチレングリコールジアクリレート（分子量５２３）１．３１ｇ（０．０７ｍｏｌ％）を用いて、同様の操作を行った。こうして、吸水剤（４）を得た。 Example 4
The amount of the 2.0 mass% aqueous solution of the polysiloxane (A) of Example 1 was changed to 15.75 g, and further using 1.31 g (0.07 mol%) of polyethylene glycol diacrylate (molecular weight 523), the same Was performed. In this way, a water absorbing agent (4) was obtained.
　〔実施例５〕
　実施例３のポリシロキサン（Ａ）をポリシロキサン（Ｂ）に変更して、同様の操作を行った。こうして、吸水剤（５）を得た。 Example 5
The same operation was performed by changing the polysiloxane (A) of Example 3 to the polysiloxane (B). In this way, a water absorbing agent (5) was obtained.
　得られた吸水剤は吸水時に液をはじくことはなかった。そして、実施例で得られた吸水剤は何れも着色がなく白いものであったことから、製造時の高温条件に耐えうる耐熱性に優れるものであった。 The obtained water-absorbing agent did not repel the liquid during water absorption. And since all the water absorbing agents obtained in the Examples were white without coloring, they were excellent in heat resistance capable of withstanding high temperature conditions during production.
　〔実施例６〕
　実施例３のポリシロキサン（Ａ）をポリシロキサン（Ｃ）に変更して、同様の操作を行った。こうして、吸水剤（６）を得た。 Example 6
The same operation was performed by changing the polysiloxane (A) of Example 3 to polysiloxane (C). Thus, a water absorbing agent (6) was obtained.
　得られた吸水剤は吸水時に液をはじくことはなかった。そして、実施例で得られた吸水剤は着色がなく白いものであったことから、製造時の高温条件に耐えうる耐熱性に優れるものであった。 The obtained water-absorbing agent did not repel the liquid during water absorption. And since the water-absorbing agent obtained in the examples was white without coloring, it was excellent in heat resistance capable of withstanding high-temperature conditions during production.
　〔比較例１〕
　実施例１のポリシロキサン（Ａ）の２．０質量％水溶液を０ｇに変更し、さらにポリエチレングリコールジアクリレート（分子量５２３）１．３１ｇ（０．０７ｍｏｌ％）を用いて、同様の操作を行った。こうして、比較吸水剤（１）を得た。 [Comparative Example 1]
A 2.0 mass% aqueous solution of the polysiloxane (A) of Example 1 was changed to 0 g, and the same operation was performed using 1.31 g (0.07 mol%) of polyethylene glycol diacrylate (molecular weight 523). . In this way, a comparative water absorbing agent (1) was obtained.
　実施例１～６および比較例１の結果をまとめたものを表１に示す。 Table 1 summarizes the results of Examples 1 to 6 and Comparative Example 1.
Figure JPOXMLDOC01-appb-T000002
 　表２から明らかなように、吸水剤（１）～（６）は未架橋の水可溶成分（水溶性高分子）が２８．７％以下であり、遠心分離機保持容量（ＣＲＣ）が９．８ｇ／g以上であることから、ポリシロキサン（Ａ）～（Ｃ）は内部架橋剤として作用し、吸水剤（１）～（６）は重合体内部に架橋構造を有していることが分かる。また、吸水剤（３）～（６）は比較吸水剤（１）よりＣＲＣが低く、水可溶分も低いことからも、ポリシロキサン（Ａ）～（Ｃ）は架橋剤として作用していることが分かる。即ち、ポリシロキサンを含む吸水剤が得られたことが理解できる。
Figure JPOXMLDOC01-appb-T000002
 As is apparent from Table 2, the water-absorbing agents (1) to (6) have an uncrosslinked water-soluble component (water-soluble polymer) of 28.7% or less and a centrifuge retention capacity (CRC) of 9 The polysiloxanes (A) to (C) act as internal crosslinking agents, and the water absorbing agents (1) to (6) have a crosslinked structure inside the polymer. I understand. In addition, since the water-absorbing agents (3) to (6) have a lower CRC and a lower water-soluble content than the comparative water-absorbing agent (1), the polysiloxanes (A) to (C) act as crosslinking agents. I understand that. That is, it can be understood that a water-absorbing agent containing polysiloxane was obtained.
　〔製造例１〕
　シグマ型羽根を２本有する内容積１０リットルのジャケット付きステンレス型双腕型ニーダーに蓋を付けて形成した反応器中で、アクリル酸５０５．６ｇ、３７質量％アクリル酸ナトリウム水溶液４４３０．８ｇ、純水５１１．７ｇ、ポリエチレングリコールジアクリレート（分子量５２３）１２．７８６ｇを溶解させて反応液とした。次にこの反応液を窒素ガス雰囲気下で、２０分間脱気した。続いて、反応液に２０質量％過硫酸ナトリウム水溶液１４．６７ｇおよび０．１質量％Ｌ－アスコルビン酸水溶液２４．４５ｇを攪拌しながら添加したところ、およそ２５秒後に重合が開始した。そして、生成したゲルを粉砕しながら、２５℃以上９０℃以下で重合を行い、重合が開始して３０分後に含水ゲル状架橋重合体を取り出した。このとき、重合が開始してから最高温度に達するまでの時間は１５分以内であった。得られた含水ゲル（含水ゲル状架橋重合体）は、その径が約５ｍｍ以下に細分化されていた。 [Production Example 1]
In a reactor formed by covering a 10-liter jacketed stainless steel double-armed kneader with two sigma-shaped blades with a lid, 505.6 g of acrylic acid, 4430.8 g of 37 mass% sodium acrylate aqueous solution, pure 511.7 g of water and 12.786 g of polyethylene glycol diacrylate (molecular weight 523) were dissolved to obtain a reaction solution. Next, this reaction solution was degassed for 20 minutes in a nitrogen gas atmosphere. Subsequently, 14.67 g of a 20% by mass sodium persulfate aqueous solution and 24.45 g of a 0.1% by mass L-ascorbic acid aqueous solution were added to the reaction solution with stirring. Polymerization started after about 25 seconds. And it superposed | polymerized at 25 degreeC or more and 90 degrees C or less, grind | pulverizing the produced | generated gel, 30 minutes after superposition | polymerization started, the water-containing gel-like crosslinked polymer was taken out. At this time, the time from the start of polymerization to the maximum temperature was within 15 minutes. The obtained water-containing gel (water-containing gel-like crosslinked polymer) was subdivided to have a diameter of about 5 mm or less.
　この細分化された含水ゲル状架橋重合体を５０メッシュの金網上に広げ、１８０℃で４５分間熱風乾燥を行い、乾燥物をロールミルで粉砕し、さらに分級操作によって、目開き７１０μｍのＪIＳ標準篩を通過した粒子を、さらに目開き１７５μｍのＪIＳ標準篩で分級し、通過した微粒子を除去することにより、質量平均粒子径（Ｄ５０）３４３μｍ、粒度分布の対数標準偏差（σζ）０．３２の不定形破砕状の吸水性樹脂（Ａ）を得た。吸水性樹脂（Ａ）の遠心分離機保持容量（ＣＲＣ）は３３．４（ｇ／ｇ）、水可溶分は６．１質量％、目開き１５０μｍのふるいを通過できる大きさの粒子の割合は１．０質量％であった。 This finely divided hydrogel cross-linked polymer is spread on a 50-mesh wire mesh, dried with hot air at 180 ° C. for 45 minutes, the dried product is pulverized with a roll mill, and further classified by a JIS standard sieve having a mesh opening of 710 μm. The particles that have passed through are further classified with a JIS standard sieve having a mesh opening of 175 μm, and the fine particles that have passed through are removed, so that the mass average particle diameter (D50) is 343 μm and the logarithmic standard deviation (σζ) of 0.32 is not satisfied. A regularly crushed water-absorbing resin (A) was obtained. Centrifuge retention capacity (CRC) of water-absorbent resin (A) is 33.4 (g / g), water-soluble content is 6.1% by mass, and the ratio of particles having a size that can pass through a sieve having an opening of 150 μm Was 1.0 mass%.
　得られた吸水性樹脂１００質量部に１，４－ブタンジオール０．３質量部、プロピレングリコール０．５質量部、純水２．７質量部の混合液からなる表面架橋剤を均一に混合した後、混合物を２１２℃で３５分間加熱処理した。その後、得られた粒子を目開き７１０μｍのＪIＳ標準篩を通過するまで解砕した。次に、解砕された粒子にペイントシェーカーテスト１を行った。こうして、表面が架橋された吸水性樹脂（Ａ）を得た。 A surface cross-linking agent composed of a mixed solution of 0.3 parts by mass of 1,4-butanediol, 0.5 parts by mass of propylene glycol and 2.7 parts by mass of pure water was uniformly mixed with 100 parts by mass of the obtained water absorbent resin. The mixture was then heat treated at 212 ° C. for 35 minutes. Thereafter, the obtained particles were crushed until they passed through a JIS standard sieve having an opening of 710 μm. Next, a paint shaker test 1 was performed on the crushed particles. Thus, a water-absorbing resin (A) having a crosslinked surface was obtained.
　〔実施例７〕
　吸水性樹脂（Ａ）１００質量部に、ポリシロキサン（Ａ）の１０．０質量％水溶液を１０質量部添加した。添加は吸水性樹脂（Ａ）を攪拌しながら、溶液が均一に添加されるように行った。この混合物を、６０℃で３０分間、無風下で静置乾燥した。こうして得られたものを吸水剤（７）とした。 Example 7
10 mass parts of 10.0 mass% aqueous solution of polysiloxane (A) was added to 100 mass parts of water absorbent resin (A). The addition was performed so that the solution was uniformly added while stirring the water absorbent resin (A). This mixture was left to dry at 60 ° C. for 30 minutes under no wind. In this manner, a water absorbing agent (7) was obtained.
　得られた吸水剤は吸水時に液をはじくことはなかった。そして、実施例で得られた吸水剤は着色がなく白いものであったことから、製造時の高温条件に耐えうる耐熱性に優れるものであった。 The obtained water-absorbing agent did not repel the liquid during water absorption. And since the water-absorbing agent obtained in the examples was white without coloring, it was excellent in heat resistance capable of withstanding high-temperature conditions during production.
　〔実施例８〕
　吸水性樹脂（Ａ）１００質量部に、ポリシロキサン（Ａ）の１０．０質量％水溶液を５．０質量部、プロピレングリコール５．０質量部からなる混合液を添加した。添加は吸水性樹脂（Ａ）を攪拌しながら、溶液が均一に添加されるように行った。この混合物を、６０℃で３０分間、無風下で静置乾燥した。こうして得られたものを吸水剤（８）とした。 Example 8
To 100 parts by mass of the water-absorbent resin (A), a mixed solution consisting of 5.0 parts by mass of a 10.0 mass% aqueous solution of polysiloxane (A) and 5.0 parts by mass of propylene glycol was added. The addition was performed so that the solution was uniformly added while stirring the water absorbent resin (A). This mixture was left to dry at 60 ° C. for 30 minutes under no wind. In this manner, a water absorbing agent (8) was obtained.
　得られた吸水剤は吸水時に液をはじくことはなかった。そして、実施例で得られた吸水剤は着色がなく白いものであったことから、製造時の高温条件に耐えうる耐熱性に優れるものであった。 The obtained water-absorbing agent did not repel the liquid during water absorption. And since the water-absorbing agent obtained in the examples was white without coloring, it was excellent in heat resistance capable of withstanding high-temperature conditions during production.
　〔実施例９〕
　吸水性樹脂（Ａ）１００質量部に、ポリシロキサン（Ａ）の１０．０質量％水溶液を５．０質量部、メタノール５．０質量部からなる混合液を添加した。添加は吸水性樹脂（Ａ）を攪拌しながら、溶液が均一に添加されるように行った。この混合物を、６０℃で３０分間、無風下で静置乾燥した。こうして得られたものを吸水剤（９）とした。 Example 9
To 100 parts by mass of the water-absorbent resin (A), a mixed solution consisting of 5.0 parts by mass of 10.0 mass% aqueous solution of polysiloxane (A) and 5.0 parts by mass of methanol was added. The addition was performed so that the solution was uniformly added while stirring the water absorbent resin (A). This mixture was left to dry at 60 ° C. for 30 minutes under no wind. In this manner, a water absorbing agent (9) was obtained.
　〔実施例１０〕
　濃度０．５Ｎの塩酸８３．６６ｇに３－アミノプロピルトリメトキシシラン４．５０ｇとテトラメトキシシラン０．４２ｇ滴下した。この溶液を室温で、２時間攪拌した。６０℃の乾燥機に移し、水分を蒸発、乾固させ、１００℃にて１０～１６時間維持し、生成物を得た。この生成物をポリシロキサン（Ｄ）とした。 Example 10
To 83.66 g of 0.5N hydrochloric acid, 4.50 g of 3-aminopropyltrimethoxysilane and 0.42 g of tetramethoxysilane were added dropwise. The solution was stirred at room temperature for 2 hours. The product was transferred to a dryer at 60 ° C. to evaporate and dry the water, and maintained at 100 ° C. for 10 to 16 hours to obtain a product. This product was designated as polysiloxane (D).
　このポリシロキサン（Ｄ）を１０質量％水溶液とした。この水溶液は透明な均一溶液だった。 This polysiloxane (D) was made into a 10% by mass aqueous solution. This aqueous solution was a clear homogeneous solution.
　吸水性樹脂（Ａ）１００質量部に、ポリシロキサン（Ｄ）の１０．０質量％水溶液を１０質量部添加した。添加は吸水性樹脂（Ａ）を攪拌しながら、溶液が均一に添加されるように行った。この混合物を、６０℃で３０分間、無風下で静置乾燥した。こうして得られたものを吸水剤（１０）とした。 10 parts by mass of a 10.0% by mass aqueous solution of polysiloxane (D) was added to 100 parts by mass of the water absorbent resin (A). The addition was performed so that the solution was uniformly added while stirring the water absorbent resin (A). This mixture was left to dry at 60 ° C. for 30 minutes under no wind. In this manner, a water absorbing agent (10) was obtained.
　実施例で得られた吸水剤は何れも着色がなく白いものであったことから、製造時の高温条件に耐えうる耐熱性に優れるものであった。 Since all of the water-absorbing agents obtained in the examples were not colored and white, they were excellent in heat resistance that can withstand high temperature conditions during production.
　〔比較例２〕
　吸水性樹脂（Ａ）を比較吸水剤（２）とした。 [Comparative Example 2]
The water absorbent resin (A) was used as a comparative water absorbent (2).
　得られた吸水剤は吸水時に液をはじくことはなかった。 The obtained water-absorbing agent did not repel the liquid during water absorption.
　〔比較例３〕
　吸水性樹脂（Ａ)１００質量部に、ポリエーテル（ポリオキシエチレン）変性シリコーン（信越化学工業株式会社製「ＫＦ－３５５Ａ」）の１０質量％水溶液を１０質量部添加した。添加は吸水性樹脂（Ａ)を攪拌しながら、溶液が均一に添加されるように行った。この混合物を、６０℃で３０分間、無風下で静置乾燥した。
こうして得られたものを比較吸水剤（３）とした。得られた吸水剤は吸水時に液をはじくことはなかった。 [Comparative Example 3]
10 parts by mass of a 10% by mass aqueous solution of polyether (polyoxyethylene) -modified silicone (“KF-355A” manufactured by Shin-Etsu Chemical Co., Ltd.) was added to 100 parts by mass of the water-absorbent resin (A). The addition was performed so that the solution was uniformly added while stirring the water absorbent resin (A). This mixture was left to dry at 60 ° C. for 30 minutes under no wind.
In this manner, a comparative water absorbing agent (3) was obtained. The obtained water-absorbing agent did not repel the liquid during water absorption.
　〔比較例４〕
　吸水性樹脂（Ａ）１００質量部に、アミノ変性シリコーン（信越化学工業株式会社製「信越シリコーンＫＦ－880」）を１質量部添加した。添加は吸水性樹脂（Ａ)を攪拌しながら、溶液が均一に添加されるように行った。この混合物を、６０℃で３０分間、無風下で静置乾燥した。こうして得られたものを比較吸水剤（４）とした。得られた吸水剤は吸水時に著しく液をはじいた。 [Comparative Example 4]
1 part by mass of amino-modified silicone (“Shin-Etsu Silicone KF-880” manufactured by Shin-Etsu Chemical Co., Ltd.) was added to 100 parts by mass of the water-absorbent resin (A). The addition was performed so that the solution was uniformly added while stirring the water absorbent resin (A). This mixture was left to dry at 60 ° C. for 30 minutes under no wind. In this manner, a comparative water absorbing agent (4) was obtained. The obtained water-absorbing agent repels liquid remarkably at the time of water absorption.
　比較例４のように、水への溶解性の低いシリコンを用いた場合、吸水時に著しく液をはじく現象が見られた。吸水剤が吸水時に液をはじいてしまうことは、それがおむつなどの衛生物品の吸水体に使用された場合、吸収速度などが十分でなくなる場合があるため好ましくない。 As in Comparative Example 4, when silicon having low solubility in water was used, a phenomenon of repelling the liquid at the time of water absorption was observed. It is not preferable that the water absorbing agent repels liquid when it absorbs water, because when it is used for a water absorbent body of a sanitary article such as a diaper, the absorption rate may not be sufficient.
　吸水剤（７）～（１０）、比較吸水剤（２）～（４）のＣＲＣ、ＳＦＣを測定した結果を表３に示した。表３において、ＡＰＴＯＭＯＳは、３－アミノプロピルトリメトキシシランを、ＴＭＯＳは、テトラメトキシシランを示している。 Table 3 shows the measurement results of CRC and SFC of the water-absorbing agents (7) to (10) and the comparative water-absorbing agents (2) to (4). In Table 3, APTOMOS represents 3-aminopropyltrimethoxysilane, and TMOS represents tetramethoxysilane.
Figure JPOXMLDOC01-appb-T000003
 　表３から明らかなように、本発明から得られた吸水剤は加圧下において高い通液性（食塩水流れ誘導性）を有する。比較例２で得られた比較吸水剤（２）はポリシロキサンが添加されていないため性能が十分ではなかった。また、比較例３で得られた比較吸水剤（３）は水溶性のポリシロキサンであるが、解離基を有さないため性能が十分でなかった。最後に、比較例４で得られた比較吸水剤（４）は水溶性の低いポリシロキサンであるため性能が十分でなく、さらに著しく液をはじいた。
Figure JPOXMLDOC01-appb-T000003
 As is apparent from Table 3, the water-absorbing agent obtained from the present invention has high liquid permeability (saline flow inductivity) under pressure. Since the comparative water absorbing agent (2) obtained in Comparative Example 2 was not added with polysiloxane, its performance was not sufficient. Moreover, although the comparative water-absorbing agent (3) obtained in Comparative Example 3 is a water-soluble polysiloxane, its performance is not sufficient because it does not have a dissociating group. Finally, since the comparative water-absorbing agent (4) obtained in Comparative Example 4 is a polysiloxane having low water solubility, the performance is not sufficient and the liquid repels remarkably.
　本発明の吸水剤は、以上のように、酸基含有不飽和単量体由来の構成単位を有する吸水性樹脂と、解離基を有する水溶性ポリシロキサンとを含むものである。 As described above, the water-absorbing agent of the present invention contains a water-absorbing resin having a structural unit derived from an acid group-containing unsaturated monomer and a water-soluble polysiloxane having a dissociating group.
　それゆえ、新規な上記ポリシロキサンを含んだ吸水剤を提供することができる。また、新たに、ポリシロキサンを有する吸水剤を提供できることによって、吸水剤の新たな設計の可能性を拡張することができるという効果を奏する。 Therefore, a novel water-absorbing agent containing the above polysiloxane can be provided. In addition, by providing a water-absorbing agent having a polysiloxane, it is possible to expand the possibility of a new design of the water-absorbing agent.
　さらに、上記構成によれば、得られる吸水剤は食塩水流れ誘導性に優れるという効果を奏する。上記の効果に加えて、耐熱性を有する吸水剤をも提供できる
　発明の詳細な説明の項においてなされた具体的な実施形態または実施例は、あくまでも、本発明の技術内容を明らかにするものであって、そのような具体例にのみ限定して狭義に解釈されるべきものではなく、本発明の精神と次に記載する請求の範囲内において、いろいろと変更して実施することができるものである。 Furthermore, according to the said structure, the obtained water absorbing agent has an effect that it is excellent in salt solution flow-inductivity. In addition to the above effects, a heat-absorbing water-absorbing agent can also be provided. The specific embodiments or examples made in the detailed description of the invention are intended to clarify the technical contents of the present invention. The present invention should not be construed as being limited to such specific examples, but can be implemented with various modifications within the spirit of the present invention and the scope of the claims set forth below. is there.
　以上のように、本発明の吸水剤は、ポリシロキサンを含み、新たな吸水性樹脂の一環として用いることができるものである。このような吸水剤からなる吸収性物品は、例えば、近年成長の著しい大人用紙オムツ、子供用オムツ、生理用ナプキン、いわゆる失禁パッド等の衛生材料等に広く利用することが可能である。 As described above, the water-absorbing agent of the present invention contains polysiloxane and can be used as a part of a new water-absorbing resin. Absorbent articles made of such a water-absorbing agent can be widely used for hygiene materials such as adult paper diapers, children's diapers, sanitary napkins and so-called incontinence pads, which have been growing rapidly in recent years.

Claims (16)

  1. 　酸基含有不飽和単量体由来の構成単位を有する吸水性樹脂と、解離基を有する水溶性ポリシロキサンとを含むことを特徴とする吸水剤。 A water-absorbing agent comprising a water-absorbing resin having a structural unit derived from an acid group-containing unsaturated monomer and a water-soluble polysiloxane having a dissociating group.
  2. 　上記解離基がアミノ基であることを特徴とする請求項１に記載の吸水剤。 The water absorbing agent according to claim 1, wherein the dissociating group is an amino group.
  3. 　上記吸水性樹脂が上記水溶性ポリシロキサンによって内部架橋されていることを特徴とする請求項１または２に記載の吸水剤。 The water-absorbing agent according to claim 1 or 2, wherein the water-absorbing resin is internally crosslinked with the water-soluble polysiloxane.
  4. 　上記吸水性樹脂の表面が上記水溶性ポリシロキサンによって表面架橋されていることを特徴とする請求項１～３の何れか１項に記載の吸水剤。 The water-absorbing agent according to any one of claims 1 to 3, wherein the surface of the water-absorbing resin is surface-crosslinked with the water-soluble polysiloxane.
  5. 　上記吸水性樹脂は、カルボキシル基を含有した不飽和単量体を重合してなることを特徴とする請求項１～４の何れか１項に記載の吸水剤。 The water-absorbing agent according to any one of claims 1 to 4, wherein the water-absorbing resin is obtained by polymerizing an unsaturated monomer containing a carboxyl group.
  6. 　上記水溶性ポリシロキサンは、以下の化学式（１）～化学式（４）
    　〔ｑ（Ｈｘ・Ｚ）・（Ｒ１）２Ｎ（ＣＨ２）ｎＳｉＯ１．５〕ｐ〔ＣｊＨ２ｊ＋１ＯＳｉＯ１．５〕１－Ｐ・・・化学式（１）
    　〔ｑ（Ｈｘ・Ｚ）・（Ｒ１）２Ｎ（ＣＨ２）ｎＳｉＯ１．５〕ｐ〔ＣＨ３（ＣＨ２）ｍＳｉＯ１．５〕１－Ｐ・・・化学式（２）
    　〔ｑ（Ｈｘ・Ｚ）・（Ｒ１）２Ｎ（ＣＨ２）ｎＳｉＯ１．５〕ｐ〔Ｒ２ＳｉＯ１．５〕１－Ｐ・・・化学式（３）
    　〔ｑ（Ｈｘ・Ｚ）・（Ｒ１）２Ｎ（ＣＨ２）ｎＳｉＯ１．５〕ｐ〔Ｒ３ＮＨ（ＣＨ２）ｎＳｉＯ１．５〕１－Ｐ・・・化学式（４）
    （上記化学式（１）～化学式（４）において、それぞれ独立して、ｎは１以上、６以下の何れかの整数であり、ｊは０以上、４以下の何れかの整数であり、ｍは０以上、４以下の何れかの整数であり、ｐはそれぞれ独立して、０を越え、１以下の範囲の値であり、Ｒ１はそれぞれ独立して、水素原子、アルキル基、置換アルキル基またはアリル基であり、Ｒ２は水素原子、ビニル基またはアリル基であり、Ｒ３は、アクリロイル基またはメタアクリロイル基であり、Ｚは１価もしくは２価の陰イオンであり、ｑは中和率を乗じた値であって、Ｒ１がアミノ基を含む場合、０．１以上２以下の範囲の数であり、Ｒ１がアミノ基を含まない場合、０．１以上１以下の範囲の数であり、ｘはＺが１価の陰イオンの場合１であり、Ｚが２価の陰イオンの場合２である。）
    で示される少なくとも何れかの分子構造を有することを特徴とする請求項１～５の何れか１項に記載の吸水剤。     The water-soluble polysiloxane has the following chemical formulas (1) to (4):
    [Q (H x · Z) · (R 1 ) 2 N (CH 2 ) n SiO 1.5 ] p [C j H 2j + 1 OSiO 1.5 ] 1-P Chemical formula (1)
    [Q (H x · Z) · (R 1) 2 N (CH 2) n SiO 1.5 ] p [CH 3 (CH 2) m SiO 1.5 ] 1-P · · · formula (2)
    [Q (H x · Z) · (R 1 ) 2 N (CH 2 ) n SiO 1.5 ] p [R 2 SiO 1.5 ] 1-P ... Chemical formula (3)
    [Q (H x · Z) · (R 1 ) 2 N (CH 2 ) n SiO 1.5 ] p [R 3 NH (CH 2 ) n SiO 1.5 ] 1-P ( 1 ) Chemical formula (4)
    (In the above chemical formulas (1) to (4), n is independently an integer of 1 or more and 6 or less, j is an integer of 0 or more and 4 or less, and m is Any integer of 0 or more and 4 or less, p is independently a value in the range of more than 0 and 1 or less, and R 1 is independently a hydrogen atom, an alkyl group, or a substituted alkyl group. Or an allyl group, R 2 is a hydrogen atom, a vinyl group or an allyl group, R 3 is an acryloyl group or a methacryloyl group, Z is a monovalent or divalent anion, and q is neutralized When R 1 includes an amino group, the number is in the range of 0.1 to 2, and when R 1 does not include an amino group, the value is in the range of 0.1 to 1 X is 1 when Z is a monovalent anion and Z is a divalent anion In the case of emissions is 2.)
    The water-absorbing agent according to any one of claims 1 to 5, wherein the water-absorbing agent has at least one molecular structure represented by the following formula.
  7. 　上記化学式（１）～化学式（４）におけるｐが、０．３以上、１以下であることを特徴とする請求項１～６の何れか１項に記載の吸水剤。 The water-absorbing agent according to any one of claims 1 to 6, wherein p in the chemical formulas (1) to (4) is 0.3 or more and 1 or less.
  8. 　上記化学式（１）～化学式（４）の各化学式において、Ｒ１が全て水素原子であり、ｎが３であることを特徴とする請求項１～７の何れか１項に記載の吸水剤。 The water-absorbing agent according to any one of claims 1 to 7, wherein in each of the chemical formulas (1) to (4), R 1 is all a hydrogen atom and n is 3.
  9. 　上記化学式（１）～化学式（４）の各化学式において、一方のＲ１が水素原子であり、他方のＲ１が２－アミノエチル基であり、ｑは０．１以上２以下の範囲の数であり、ｘが１であることを特徴とする請求項１～７の何れか１項に記載の吸水剤。 In each of the chemical formulas (1) to (4), one R 1 is a hydrogen atom, the other R 1 is a 2-aminoethyl group, and q is a number in the range from 0.1 to 2 The water-absorbing agent according to any one of claims 1 to 7, wherein x is 1.
  10. 　吸水剤１００質量部に対する固形分が、７０質量部以上であることを特徴とする請求項１～９の何れか１項に記載の吸水剤。 The water-absorbing agent according to any one of claims 1 to 9, wherein the solid content with respect to 100 parts by mass of the water-absorbing agent is 70 parts by mass or more.
  11. 　酸基含有不飽和単量体１００質量部に対し、上記水溶性ポリシロキサンを０．００１質量部以上、１０質量部以下用いることによって得られたことを特徴とする請求項１～１０の何れか１項に記載の吸水剤。 11. The method according to claim 1, wherein the water-soluble polysiloxane is used in an amount of 0.001 to 10 parts by mass with respect to 100 parts by mass of the acid group-containing unsaturated monomer. The water absorbing agent according to Item 1.
  12. 　請求項１～１１の何れか１項に記載の吸水剤を含むことを特徴とする吸収性物品。 An absorbent article comprising the water-absorbing agent according to any one of claims 1 to 11.
  13. 　酸基含有不飽和単量体を内部架橋剤の存在下において架橋重合することによって得られた含水ゲル状架橋重合体を、乾燥し、吸水剤を得る吸水剤の製造方法において、
    　上記内部架橋剤として、アミノ基を有する水溶性ポリシロキサンを用いることを特徴とする吸水剤の製造方法。     In the method for producing a water-absorbing agent, a water-containing gel-like crosslinked polymer obtained by crosslinking polymerization of an acid group-containing unsaturated monomer in the presence of an internal crosslinking agent is dried to obtain a water-absorbing agent.
    A method for producing a water-absorbing agent, wherein a water-soluble polysiloxane having an amino group is used as the internal cross-linking agent.
  14. 　酸基含有不飽和単量体を内部架橋剤の存在下において架橋重合することによって得られた含水ゲル状架橋重合体を、乾燥し、吸水剤を得る吸水剤の製造方法において、
    　上記含水ゲル状架橋重合体を乾燥し、得られた含水ゲル状架橋重合体乾燥物に、アミノ基を有する水溶性ポリシロキサンを用いて含水ゲル状架橋重合体乾燥物を表面処理することを特徴とする吸水剤の製造方法。     In the method for producing a water-absorbing agent, a water-containing gel-like crosslinked polymer obtained by crosslinking polymerization of an acid group-containing unsaturated monomer in the presence of an internal crosslinking agent is dried to obtain a water-absorbing agent.
    The above hydrogel crosslinked polymer is dried, and the resulting hydrogel crosslinked polymer dried product is surface-treated with a water-soluble polysiloxane having an amino group. A method for producing a water-absorbing agent.
  15. 　酸基含有不飽和単量体を内部架橋剤の存在下において架橋重合することによって得られた含水ゲル状架橋重合体を、乾燥し、吸水剤を得る吸水剤の製造方法において、
    　上記含水ゲル状架橋重合体を乾燥し、得られた含水ゲル状架橋重合体乾燥物に表面架橋処理を施した後に、さらに、アミノ基を有する水溶性ポリシロキサンを表面架橋処理が施された含水ゲル状架橋重合体乾燥物に添加することを特徴とする吸水剤の製造方法。     In the method for producing a water-absorbing agent, a water-containing gel-like crosslinked polymer obtained by crosslinking polymerization of an acid group-containing unsaturated monomer in the presence of an internal crosslinking agent is dried to obtain a water-absorbing agent.
    The water-containing gel-like cross-linked polymer is dried, and the obtained water-containing gel-like cross-linked polymer dried product is subjected to surface cross-linking treatment, and then water-soluble polysiloxane having amino groups is subjected to surface cross-linking treatment. A method for producing a water-absorbing agent, which is added to a dried gel-like crosslinked polymer.
  16. 　上記水溶性ポリシロキサンは、以下の化学式（１）～化学式（４）
    　〔ｑ（Ｈｘ・Ｚ）・（Ｒ１）２Ｎ（ＣＨ２）ｎＳｉＯ１．５〕ｐ〔ＣｊＨ２ｊ＋１ＯＳｉＯ１．５〕１－Ｐ・・・化学式（１）
    　〔ｑ（Ｈｘ・Ｚ）・（Ｒ１）２Ｎ（ＣＨ２）ｎＳｉＯ１．５〕ｐ〔ＣＨ３（ＣＨ２）ｍＳｉＯ１．５〕１－Ｐ・・・化学式（２）
    　〔ｑ（Ｈｘ・Ｚ）・（Ｒ１）２Ｎ（ＣＨ２）ｎＳｉＯ１．５〕ｐ〔Ｒ２ＳｉＯ１．５〕１－Ｐ・・・化学式（３）
    　〔ｑ（Ｈｘ・Ｚ）・（Ｒ１）２Ｎ（ＣＨ２）ｎＳｉＯ１．５〕ｐ〔Ｒ３ＮＨ（ＣＨ２）ｎＳｉＯ１．５〕１－Ｐ・・・化学式（４）
    （上記化学式（１）～化学式（４）において、それぞれ独立して、ｎは１以上、６以下の何れかの整数であり、ｊは０以上、４以下の何れかの整数であり、ｍは０以上、４以下の何れかの整数であり、ｐはそれぞれ独立して、０を越え、１以下の範囲の値であり、Ｒ１はそれぞれ独立して、水素原子、アルキル基、置換アルキル基またはアリル基であり、Ｒ２は水素原子、ビニル基またはアリル基であり、Ｒ３は、アクリロイル基またはメタアクリロイル基であり、Ｚは１価もしくは２価の陰イオンであり、ｑは中和率を乗じた値であって、Ｒ１がアミノ基を含む場合、０．１以上２以下の範囲の数であり、Ｒ１がアミノ基を含まない場合、０．１以上１以下の範囲の数であり、ｘはＺが１価の陰イオンの場合１であり、Ｚが２価の陰イオンの場合２である。）
    で示される少なくとも何れかの分子構造を有することを特徴とする請求項１３～１５の何れか１項に記載の吸水剤の製造方法。     The water-soluble polysiloxane has the following chemical formulas (1) to (4):
    [Q (H x · Z) · (R 1 ) 2 N (CH 2 ) n SiO 1.5 ] p [C j H 2j + 1 OSiO 1.5 ] 1-P Chemical formula (1)
    [Q (H x · Z) · (R 1) 2 N (CH 2) n SiO 1.5 ] p [CH 3 (CH 2) m SiO 1.5 ] 1-P · · · formula (2)
    [Q (H x · Z) · (R 1 ) 2 N (CH 2 ) n SiO 1.5 ] p [R 2 SiO 1.5 ] 1-P ... Chemical formula (3)
    [Q (H x · Z) · (R 1 ) 2 N (CH 2 ) n SiO 1.5 ] p [R 3 NH (CH 2 ) n SiO 1.5 ] 1-P ( 1 ) Chemical formula (4)
    (In the above chemical formulas (1) to (4), n is independently an integer of 1 or more and 6 or less, j is an integer of 0 or more and 4 or less, and m is Any integer of 0 or more and 4 or less, p is independently a value in the range of more than 0 and 1 or less, and R 1 is independently a hydrogen atom, an alkyl group, or a substituted alkyl group. Or an allyl group, R 2 is a hydrogen atom, a vinyl group or an allyl group, R 3 is an acryloyl group or a methacryloyl group, Z is a monovalent or divalent anion, and q is neutralized When R 1 includes an amino group, the number is in the range of 0.1 to 2, and when R 1 does not include an amino group, the value is in the range of 0.1 to 1 X is 1 when Z is a monovalent anion and Z is a divalent anion In the case of emissions is 2.)
    The method for producing a water-absorbing agent according to any one of claims 13 to 15, wherein the water-absorbing agent has at least one molecular structure represented by the following formula.
PCT/JP2009/051115 2008-01-24 2009-01-23 Water absorbent and process for production thereof WO2009093708A1 (en)

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