WO2016200112A1

WO2016200112A1 - Method for manufacturing absorbent core having enhanced wet strength

Info

Publication number: WO2016200112A1
Application number: PCT/KR2016/005988
Authority: WO
Inventors: 김영삼; 유주환
Original assignee: 주식회사 엘지화학
Priority date: 2015-06-09
Filing date: 2016-06-07
Publication date: 2016-12-15

Abstract

The present invention relates to an absorbent core of an absorbent article comprising: a liquid-permeable top sheet; an absorbent distribution layer disposed on the lower portion of the top sheet; an absorbent core, disposed on the absorbent distribution layer, for absorbing and retaining liquid; and a liquid-impermeable backsheet disposed on the lower portion of the absorbent core, wherein the absorbent core comprises a highly water-absorbent resin and crossed modified cross-section yarns prepared by mixing polyethylene terephthalate (PET) with an aqueous dispersion containing particles having properties of i) BET specific surface area of 300 to 1500 m2/g and ii) porosity of 50 % or more. Compared to a conventional absorbent core, the absorbent core of the present invention has effects of convenient storage, activity when being worn, and enhanced liquid permeability.

Description

Method for producing absorbent core with enhanced wet strength

This application claims the benefit of priority based on Korean Patent Application No. 10-2015-0081162 dated June 09, 2015 and Korean Patent Application No. 10-2016-0044888 dated April 12, 2016. All content disclosed in the literature is included as part of this specification.

The present invention relates to a method for manufacturing an absorbent core with enhanced wet strength, and more particularly, wet strength prepared from cross-sectional cross-section yarn and superabsorbent polymer into which particles having specific properties are introduced into polyethylene terephthalate (PET) It relates to an enhanced absorbent core.

Disposable diapers absorb hygiene such as blood, urine, and menstrual blood to be hygienic and convenient for the user to use. In general, disposable diapers absorb products secreted by various physiological actions of the wearer (for example, urine, blood, menstrual blood, etc.), and include diapers, women's sanitary napkins, panty liners, etc. .

These disposable diapers include as a basic component a liquid permeable top sheet, a liquid impermeable back sheet that forms an outer surface when worn, and an absorbent core disposed between the top sheet and the back sheet. It is composed. Of these, the absorption core is an important part that absorbs secretions such as urine. Absorbent cores are means for absorbing and retaining liquid secretions. Absorbent cores are typically liquid absorbents, such as fluff pulp and super absorbent polymers, and tissues for packaging them. And the like, and rapidly absorb body fluid passing through the liquid permeable top sheet and retain the body fluid to prevent the absorbed body fluid from contacting the skin again.

In this regard, Korean Patent Laid-Open Publication No. 2005-0032747 discloses an ultra-thin absorbent core of a disposable diaper manufactured using fluff pulp and a method of manufacturing the same. The use of a large amount of pulp for the conveying role due to the characteristics and the number of voids is a weak point in the recent trend of ultra-thin diapers.

Therefore, there is a need for the development of a new concept of core constituents capable of achieving ultra-thin while exhibiting performance equivalent to or higher than existing cellulose pulp.

The present invention is to solve the problems of the prior art as described above to provide a cross-sectional cross-sectional yarn and cross-sectional cross-sectional yarns having a specific property in polyethylene terephthalate (PET) and a wet strength reinforced absorbent core made from a super absorbent polymer Its purpose is to.

It is also an object of the present invention to provide an ultra-thin absorbent article which is a recent trend using the absorbent core.

The present invention relates to a liquid permeable top sheet, an absorbent dispersion layer positioned below the upper sheet, an absorbent core positioned below the absorbent dispersion layer to absorb and retain liquid, and a liquid impermeable backsheet positioned below the absorbent core. As an absorbent core of an absorbent article comprising

The absorbent core comprises an aqueous dispersion comprising polyethylene terephthalate (PET) i) particles having a BET specific surface area of 300 to 1500 m ² / g and ii) porosity of 50% or more. It provides an absorbent core, characterized in that it comprises a cross-shaped cross-section yarn and a super absorbent polymer prepared by mixing.

The present invention also provides an aqueous dispersion comprising 1) polyethylene terephthalate, i) a particle having a BET specific surface area of 300 to 1500 m ² / g to ii) a porosity of at least 50%. Manufacturing a cross-shaped cross-section yarn to obtain;

2) forming an absorbent core shape by depositing the cross-sectional cross-section yarn and a super absorbent polymer; And

3) compressing the absorbent core appearance;

It provides a method for producing an absorbent core comprising a.

The present invention also provides an absorbent article comprising the absorbent core.

Absorbent core provided in the present invention can produce an ultra-thin absorbent article while exhibiting the same or better performance than the existing cellulose pulp has the advantage of ensuring the convenience of storage, activity when worn.

In addition, the absorbent core provided in the present invention includes particles having specific properties in the production of cross-sectional cross-section yarns to increase porosity and impart high hydrophobicity, thereby improving liquid permeability.

1 is a schematic diagram of a cellulose absorbent core of the prior art.

2 is a schematic diagram of a release cross-sectional yarn absorbent core of the present invention.

3 is a schematic diagram of a structure of an absorbent article including a release cross-section yarn absorbent core of the present invention.

4 is a schematic diagram of a structure of an absorbent article including a cellulose absorbent core of the prior art.

5 and 6 show the test procedure of Test Example 1.

7 shows the test results of Test Example 1.

8 shows the manufacturing process of the absorbent core.

Hereinafter, the present invention will be described in detail.

The absorbent core comprises an aqueous dispersion comprising polyethylene terephthalate (PET) i) particles having a BET specific surface area of 300 to 1500 m ² / g and ii) porosity of 50% or more. It relates to an absorbent core, characterized in that it comprises a cross-sectional cross-section yarn and a super absorbent polymer prepared by mixing.

The present invention also provides a water dispersion comprising 1) polyethylene terephthalate comprising: i) particles having a BET specific surface area of from 300 to 1500 m ² / g to ii) a porosity of at least 50%; Adding to form a cross-sectional cross-section yarn;

3) compressing the absorbent core appearance; It relates to a method for producing an absorbent core comprising a.

The absorbent core may include a liquid permeable top sheet, an absorbent dispersion layer positioned below the upper sheet, an absorbent core positioned below the absorbent dispersion layer to absorb and retain liquid, and a liquid impermeable back sheet positioned below the absorbent core. construct an absorbent article comprising a backsheet).

The 'polyethylene terephthalate (PET)' consists of polymerized units of monomer ethylene terephthalate and has a repeating unit of C ₁₀ H ₈ O ₄ . Polyethylene terephthalate (PET) has excellent heat resistance, stiffness, electrical properties, etc., and its ultimate strength is only slightly reduced even at high temperatures for a long time. Because it belongs to crystalline plastics, it has good resistance to oils such as diesel oil. However, due to ester bonds in the molecular chain, the molded product is prone to change when immersed in acid or alkali over high temperature and long time.

The present invention uses polyethylene terephthalate in the form of cross-shaped cross-sectional yarns.

The cross-shaped cross section yarn refers to a yarn in which the state of the cross section of the yarn is changed by changing the shape of the nozzle used for spinning synthetic fibers from a general circle to a cross shape.

Existing absorbent cores have a circular cross section, and due to such structural limitations, there is a problem in that the mobility of liquids is not easy, so that absorbent articles are manufactured in such a manner as to secure porosity using a large amount of pulp (FIG. 1). However, in the case of the present invention by using a biodegradable cross-sectional cross-section (NCCS, non-circular cross section) to produce a core with the maximum porosity to improve the fluidity, the mobility of the liquid. In addition, even if a small amount of fibers can be sufficiently secured porosity, it is possible to expect the effect of weight reduction, thickness reduction (Fig. 2).

The cross-sectional cross-sectional yarn fibers included in the absorbent core of the present invention have a polyethylene terephthalate having i) 300 to 1500 m ² / g of BET specific surface area to ii) porosity of 50% or more. It is prepared by adding an aqueous dispersion containing particles.

As the particles having the above properties are included, the porosity is increased and high hydrophobicity is imparted to improve the fluid permeability.

In one embodiment of the present invention, the particles have a particle size of 2 nm to 50 ㎛, or the contact angle to the water is preferably superhydrophobic of 125 ° or more, it is more preferable to have both the particle size and contact angle characteristics It is not limited to this.

In one embodiment of the present invention, the aqueous dispersion may include the particles, water and an organic solvent, the organic solvent is methanol, ethanol, isopropyl alcohol (IPA) and It may be at least one selected from the group consisting of acetone, and more preferably use isopropyl alcohol (IPA).

Particles introduced during the preparation of the cross-sectional cross-section of the present invention has a particle size of 2 nm to 50 μm. The particles may also have a BET specific surface area of 300 to 1500 m ² / g, preferably 500 to 1500 m ² / g, more preferably 700 to 1500 m ² / g. In addition, the particles may have a superhydrophobicity of 125 ° or more, preferably superhydrophobicity of 140 ° or more, and more preferably 145 ° or more. The particles can also have a porosity of at least 50%, preferably at least 90% of a porosity.

Particles of the present invention is not limited to the component as long as the material having the properties of i) to ii), specifically, inorganic oxides such as silica (SiO ₂ ), alumina, carbon (Carbon) and titania (TiO ₂ ), inorganic Compounds, organic polymers, ion exchange resins, metals, metal salts, and the like may be used, but are not limited thereto. It is preferable to use silica (SiO ₂ ).

The particles may be included in an amount of 1 to 25 parts by weight based on 100 parts by weight of a mixture of water and an organic solvent. When the particles are included in the above range, the dispersion proceeds well and there is no gelation due to dispersion instability during long term storage. Therefore, it is not necessary to include additives such as additives, pH adjusters, surfactants, or stabilizers to prevent gelation, so that the original properties of the particles may be maintained at the time of drying. Thus, there is no need to remove the adjuvant through pre-treatment before the process and have the advantage that it can be applied directly to the process.

In addition, the mixing rate after the aqueous dispersion is added is preferably mixed at a speed of 200 to 3000 rpm. If the mixing speed is less than 200 rpm, the effect due to mixing does not appear sufficiently, and if the mixing speed exceeds 3000 rpm, there is a problem of excessive grinding.

In addition, it is preferable to add an aqueous dispersion containing particles to the cross-sectional cross-sectional yarn and then to mix for 10 seconds to 3 minutes. If the mixing time is less than 10 seconds, the effect of mixing does not appear sufficiently, and if the mixing time exceeds 3 minutes, there is a problem of being excessively ground.

In one embodiment of the present invention, the absorbent core preferably includes a cross-sectional cross-section yarn and a super absorbent polymer in a ratio of 1: 5 to 5: 1, but is not limited thereto.

In one embodiment of the present invention, the absorbent article is a diaper, training pants, absorbent underpants, adult incontinence products, sanitary napkins, feminine hygiene products such as tampons and panty liners, wound care products such as bandages and other articles, etc. It may include, but is preferably a diaper.

The absorbent article absorbs body fluids such as blood, urine, and menstrual blood so that the user can use them hygienically and conveniently.

Such absorbent articles typically consist of a liquid permeable topsheet that is in direct contact with the skin of the wearer when worn, a liquid impermeable backsheet that forms an outer surface when worn, an absorbent core disposed between the topsheet and the backsheet, and an elastomer It comprises a leg flap and a fastening means as a basic component.

Among the above components, the top sheet is generally composed of soft to the touch and does not irritate the skin of the wearer, in particular the top sheet should have a physical property that can quickly pass the liquid body secretion to the absorbent core . Top sheets suitable as having these properties are made and used from a wide range of materials such as porous plastic films, natural fibers, synthetic fibers or mixtures of natural and synthetic fibers.

Absorbent core is a means for absorbing and retaining liquid secretions. It absorbs body fluids through the liquid permeable top sheet at high speed and prevents the absorbed body fluids from contacting the skin again. Perform the function you own. The size, shape (e.g., rectangular, hourglass, etc.), structure, and absorbent capacity of the absorbent core are adapted to fit the wearer from infant to adult, and the absorbent core is provided on the back sheet by known attachment means. Attached and fixed.

The backsheet is impermeable to the liquid so that the body secretions absorbed and absorbed by the absorbent core do not contaminate or wet products that are in direct contact with the diaper, such as the wearer's clothing or bed sheet. The back sheet is preferably impermeable to liquids and permeable to gases. As a film having such physical properties, a plastic film has been generally used, and in recent years, a material obtained by adhering a nonwoven fabric to a polyethylene film has been widely used.

The leg flaps are positioned adjacent each longitudinal edge to allow the diaper to be worn and secured to the wearer's leg.

The fastening means performs a function of wearing a disposable diaper on the body and maintaining its wearing state. Fastening means are widely used fastening members such as adhesive tape tabs or hooks and loops.

The various members of each of the components of the diaper are adhesively fixed by hot melt adhesive, heat fusion, or other bonding method which is well known in the diaper field to form the diaper.

Conventional absorbent cores are prepared using fluff pulp, starch graft copolymers, cross-linked carboxymethylcellulose derivatives, modified hydrophilic acrylates, etc., made by grinding wood pulp on a fibrous web. The absorbent resin has been produced by uniformly or intentionally distributing it uniformly, and then adding water to it and then compressing it in order to improve the strength (Integrity) of the absorbent core.

Recent diapers tend to become lighter and lighter as they are more ergonomically developed. This improves breathability due to lightness and thinness when worn, improves freshness, and prevents side effects such as itching and rashes when worn for a long time with excellent breathability. to be.

Accordingly, the absorbent article of the present invention improves fluidity and liquid mobility by manufacturing an absorbent core having a maximum porosity by replacing the cellulose fluff pulp contained in the core of the existing absorbent article with cross-shaped cross-sectional yarn fibers.

Superabsorbent resins used in the absorbent core of the present invention are prepared by the steps and methods commonly used in the art.

The 'super absorbent resin' can absorb at least about 15 times its weight, preferably at least about 25 times its weight in water. The superabsorbent resin can be selected from natural, synthetic, modified natural polymers and the like. The superabsorbent resin may also be an organic compound including inorganic materials such as silica gel, or natural materials such as agar, pectin, guar gum and the like, and synthetic materials such as synthetic hydrogel polymers. Such hydrogel polymers include, for example, alkali metal salts of polyacrylic acid; Polyacrylamide; Polyvinyl alcohol; Ethylene maleic anhydride copolymers; Polyvinyl ethers; Hydroxypropyl cellulose; Polyvinyl morpholinone; Vinyl sulfonic acids, polyacrylates, polyacrylamides, polymers and copolymers of polyvinyl pyridine and the like. Other suitable polymers include hydrolyzed acrylonitrile grafted starch, acrylic acid grafted starch and isobutylene maleic anhydride copolymers and mixtures thereof. The hydrogel polymer is preferably weakly crosslinked to render the material substantially water insoluble. The crosslink can be, for example, by light irradiation or by covalent bonds, ionic bonds, van der Waals bonds or hydrogen bonds. Superabsorbent materials may be in any form suitable for use in absorbent structures, including particles, fibers, flakes, spheres, and the like.

In one embodiment of the present invention, the absorbent core preferably includes a cross-sectional cross-section yarn and a super absorbent polymer in the same weight, but is not limited thereto.

The backsheet is impermeable to the liquid so that the body secretions absorbed and absorbed by the absorbent core do not contaminate or wet products that are in direct contact with the diaper, such as the wearer's clothing or bed sheet. The back sheet is preferably impermeable to liquids and permeable to gases. As a film having such physical properties, a plastic film has been generally used, and recently, a material in which a nonwoven fabric is bonded to a polyethylene film has been widely used.

Hereinafter, the present invention will be described in more detail with reference to non-limiting examples. Embodiment of this invention disclosed below is an illustration to the last, and the scope of the present invention is not limited to these embodiment. The scope of the invention is indicated in the appended claims, and moreover contains all modifications within the meaning and range equivalent to the claims. In addition, "%" and "part" which show content in a following example and a comparative example are a mass reference | standard unless there is particular notice.

실시예Example

Example 1 Preparation of Absorbent Core

(1) manufacture of cross-shaped cross-section yarns

After addition of an aqueous dispersion containing 10% by weight of silica airgel (AeroZel ^TM, JIOS G) in the four cross-modified cross-section made of a polyethylene terephthalate (㈜ Huvis COOLERVER ^TM) in 1% by weight, in the Ploughshare mixer (JS tech) By stirring, a cross-sectional cross-section yarn containing silica airgel was prepared. The silica airgel aqueous dispersion was prepared in the ratio of isopropyl alcohol: water: silica airgel 45: 45: 10% by weight.

(2) Preparation of Absorbent Core

Absorbent core was evenly sprayed with a superabsorbent polymer on the cross-sectional cross-section yarn and repeatedly deposited four times using a core evaporator, and manufactured by pressing with a roll mill. The ratio of cross-shaped cross-section yarn to superabsorbent resin is 55% by weight to 45% by weight. The manufacturing process is shown in FIG. 8.

Comparative Example 1. Cellulose Pulp Absorption Core

An absorbent core was prepared in the same manner as in Example 1 except that cellulose pulp was used instead of the cross-sectional cross-section yarns.

Comparative Example 2. Absorbent Core without Particles

An absorbent core was prepared in the same manner as in Example 1, except that the aqueous dispersion including the silica airgel (AeroZel ^™ , JIOS Co., Ltd.) of Example 1 was not mixed.

시험예Test Example

In order to evaluate the physical properties of the absorbent core according to Example 1 and Comparative Examples 1 to 2, the following experiment was conducted.

Test Example 1. Strike Thru Experiment

In the absorbent cores prepared in Example 1 and Comparative Examples 1 and 2, the time from the moment the brine was added through the inlet to the total absorption of the brine was measured. The measurement was repeated three times on the same sample. This fast time indicates that the brine passes through the absorbent core and is highly liquid. The test procedure is shown in FIGS. 5 to 7. The results are shown in Table 1.

Table 1

Measurement property		Comparative Example 1	Comparative Example 2	Example 1
Strike thru (sec)	Primary	59	57	56
	Secondary	63	60	57
	3rd	83	74	66

As shown in Table 1, in the case of the absorbent core according to the present invention, it was found that the liquid permeability is improved.

Claims

A liquid permeable top sheet, an absorbent dispersion layer positioned below the upper sheet, an absorbent core positioned below the absorbent dispersion layer to absorb and retain liquid, and a liquid impermeable backsheet positioned below the absorbent core; As the absorbent core of the absorbent article to

The absorbent core comprises an aqueous dispersion comprising polyethylene terephthalate (PET) i) particles having a BET specific surface area of 300 to 1500 m 2 / g to ii) porosity of 50% or more. Absorbent core, characterized in that it comprises a cross-shaped cross-section yarn and a super absorbent polymer prepared by mixing.
The method according to claim 1,

The particles are absorbent core, characterized in that having a particle size of 2 nm to 50 ㎛.
The method according to claim 1,

The particles are absorbent core, characterized in that the contact angle to the water is superhydrophobic more than 125 °.
The method according to claim 1,

The particles are absorbent core, characterized in that the particle size of 2 nm to 50 ㎛ and the contact angle to water has a super hydrophobicity of 125 ° or more.
The method according to claim 1,

And the particles have a BET specific surface area of 500-1500 m 2 / g.
The method according to claim 5,

And the particles have a BET specific surface area of 700 m 2 / g to 1500 m 2 / g.
The method according to claim 3,

The particles are absorbent core, characterized in that the contact angle to the water has a super hydrophobicity of 140 ° or more.
The method according to claim 7,

The particles are absorbent core, characterized in that the contact angle to the water has a superhydrophobicity of 145 ° or more.
The method according to claim 1,

And the particles have a porosity of at least 90%.
The method according to claim 1,

The aqueous dispersion further comprises water and an organic solvent in addition to the particles.
The method according to claim 10,

The particles are absorbent core, characterized in that contained in 1 to 25 parts by weight based on 100 parts by weight of water and organic solvent.
The method according to claim 10,

The organic solvent is at least one member selected from the group consisting of methanol (methanol), ethanol (ethanol), isopropyl alcohol (isoA), and acetone (acetone).
The method according to claim 12,

The organic solvent is isopropyl alcohol (isopropyl alcohol, IPA) characterized in that the absorbent core.
The method according to claim 1,

The particle is an absorbent core, characterized in that at least one member selected from the group consisting of silica (SiO 2 ), alumina, carbon (Carbon) and titania (TiO 2 ).
The method according to claim 14,

And said particles are silica (SiO 2 ).
The method according to claim 1,

Absorbent core, characterized in that it comprises a cross-shaped cross-sectional yarn and a super absorbent polymer in the same weight.
The method according to claim 1,

And the absorbent article is a diaper.
1) Cross-shaped cross-section by adding an aqueous dispersion comprising polyethylene terephthalate i) particles having a BET specific surface area of 300 to 1500 m 2 / g to ii) porosity of 50% or more Preparing a yarn;

2) forming an absorbent core shape by depositing the cross-sectional cross-section yarn and a super absorbent polymer; And

3) compressing the absorbent core appearance;

Method for producing an absorbent core comprising a.
An absorbent article comprising the absorbent core of claim 1.