JP2005186015A - Absorbent, absorber containing the same and absorbent article - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain an adsorbent excellent in the leak resistance of viscous fluid excretion. <P>SOLUTION: The absorbent contains a water absorbing resin (A) and a viscosity adjusting agent (B1) having a polyvalent metal element and/or a viscosity adjusting agent (B2) having at least two ionic groups. The viscosity change index (VI) of the viscosity adjusting agent (B1) and/or the viscosity adjusting agent (B2) is preferably 1.5-800. The polyvalent metal element is preferably calcium, aluminum and/or iron. The ionic group is preferably carboxyl (COOH) group, a carboxylate (COO<SP>-</SP>) group and/or a quaternary ammonia NR<SB>3</SB><SP>+</SP>(wherein R is a 1-20C organic group). <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

The present invention relates to an absorbent, an absorbent body containing the absorbent, and an absorbent article.

Conventionally, absorbent articles (paper diapers, breast milk pads, etc.) have been improved with respect to the absorption function (particularly resistance to liquids) of liquid excreta such as urine, breast milk or sweat. There has been no known absorbent that has been improved or examined with respect to the absorption function (particularly, resistance to moles) of (soft stool and vomit). On the other hand, an absorbent article (Patent Document 1) in which absorbent bodies of different materials are laminated is known as an absorbent article that is improved in the moisture resistance of viscous liquid excrement by devising the configuration and arrangement of the absorbent article. It has been.
JP 2003-299694 A

The device and arrangement of the absorbent article alone are not always satisfactory with respect to the liquid resistance of viscous liquid excrement, and further improvement is strongly desired.
That is, the object of the present invention is to provide an absorbent having excellent resistance to leakage of viscous liquid excreta.

As a result of intensive studies in order to achieve the above object, the present inventors have found that the above object can be achieved by using a specific viscosity modifier, and have reached the present invention.
That is, the absorbent of the present invention is characterized by the water absorbent resin (A), the viscosity modifier (B1) having a polyvalent metal element and / or the viscosity modifier (B2) having at least two ionic groups. The point which contains is made into a summary.

  The absorbent of the present invention is extremely excellent in the resistance to leakage of viscous liquid excrement such as loose stool and vomit. That is, even if it is a viscous liquid excrement, this absorption is remarkably good, and as a result, extremely excellent resistance to leakage is exhibited. Moreover, since the absorbent of the present invention firmly retains the absorbed moisture, it exhibits excellent anti-sag and anti-fogging properties. Therefore, the absorbent of the present invention is very useful for hygiene products such as disposable diapers and napkins.

As the water absorbent resin (A), a normal water-swellable crosslinked polymer or the like can be used, and the polymers (1) to (8) are exemplified. A mixture of two or more of these polymers may be used.
(1) Starch-acrylic acid (salt) graft-crosslinked copolymer (a1) described in JP-B-53-46199 or JP-B-53-46200.
(2) Crosslinked polyacrylic acid (salt) (a2) obtained by aqueous solution polymerization (adiabatic polymerization, thin film polymerization, spray polymerization, etc.) described in JP-A-55-133413.
(3) A crosslinked polyacrylic acid (salt) (a3) obtained by reverse phase suspension polymerization described in JP-B-54-30710, JP-A-56-26909, or JP-A-11-5808.
(4) A saponified product (a4) of a copolymer of a vinyl ester and an unsaturated carboxylic acid or a derivative thereof described in JP-A-52-14689 or JP-A-52-27455.
(5) A copolymer (a5) of an acrylic acid (salt) and a sulfo (sulfonate) group-containing monomer described in JP-A-58-2312 or JP-A-61-36309.
(6) A saponified product (a6) of a crosslinked isobutylene-maleic anhydride copolymer described in US Pat. No. 4,389,513.
(7) A hydrolyzate (a7) of starch-acrylonitrile copolymer described in JP-A-46-43995.
(8) A crosslinked carboxymethylcellulose derivative (a8) described in US Pat. No. 4,650,716.

  Among these, from the viewpoint of production cost, etc., starch-acrylic acid (salt) graft copolymer cross-linked product (a1), cross-linked polyacrylic acid (salt) obtained by aqueous solution polymerization (a2) and obtained by reverse phase suspension polymerization The cross-linked polyacrylic acid (salt) (a3) obtained is preferable, and (a2) and (a3) are more preferable.

Furthermore, the water absorbent resin (A) can crosslink the vicinity of the surface of (A) (surface crosslinking treatment). Thus, the water-absorbent resin (A) in which the vicinity of the surface is subjected to crosslinking treatment is preferable because the amount of absorption under load is increased.
Examples of the surface cross-linking agent include polyhydric glycidyl described in JP-A-59-189103, polyhydric alcohol, polyhydric amine described in JP-A-58-180233, JP-A-61-16903, and the like. , Polyaziridines and polyisocyanates, silane coupling agents described in JP-A-61-211305 or JP-A-61-225212 and the like, and JP-A-51-136588 or JP-A-61- And multivalent metals described in Japanese Patent No. 257235. Of these surface cross-linking agents, form a strong covalent bond with a carboxyl (carboxylate) group to obtain a water-absorbing resin excellent in the amount of absorption under load, and allow the cross-linking reaction to be performed at a relatively low temperature. From the standpoint of being economical and economical, polyvalent glycidyl, polyvalent amine and silane coupling agent are preferred, polyvalent glycidyl and silane coupling agent are more preferred, and polyvalent glycidyl is particularly preferred.

When using a surface cross-linking agent, the amount (% by weight) of the surface cross-linking agent is not particularly limited because it can be variously changed depending on the type of surface cross-linking agent, surface cross-linking conditions, target performance, etc. From the viewpoint of absorption performance, 0.001 to 3 is preferable, more preferably 0.005 to 2, particularly preferably 0.01 to 1, based on the total weight of the raw material monomer of the water absorbent resin (A). is there.
When the water-absorbing resin (A) is produced in the presence of water (usually produced in this way), the surface cross-linking treatment is performed by water-containing resin (WA) containing water-absorbing resin (A) and water. May be carried out at any stage such as before drying (WA), after drying (WA), and after drying (WA), but from the viewpoint of adjusting the crosslinking conditions, etc., during drying (WA) or (WA) The stage after drying is preferred.

As a method for performing this surface cross-linking treatment, a conventionally known method can be applied. A mixed solution composed of a surface cross-linking agent, water and / or an organic solvent is mixed with a water absorbent resin (A) or a water-containing resin (WA), and heated. A method of reacting can be applied.
In the case of the above method, the amount (% by weight) of water used for the surface cross-linking treatment is determined from the viewpoint of penetrability of the surface cross-linking agent into the water-absorbent resin (A). Based on the total weight of the monomers, 1 to 10 is preferable, more preferably 1.5 to 8, and particularly preferably 2 to 7.

In the case of the above method, as the type of organic solvent used in the surface cross-linking treatment, a conventionally known hydrophilic solvent or the like can be used, and the penetrability of the surface cross-linking agent into the water absorbent resin (A), the surface Although it can be selected as appropriate in consideration of the reactivity of the crosslinking agent, etc., it dissolves in water at an arbitrary ratio such as alcohol having 1 to 4 carbon atoms (methanol, ethanol, ethylene glycol, propylene glycol, diethylene glycol, etc.). Preferred hydrophilic solvents are preferred.
An organic solvent may be used independently and may use 2 or more types together.
Moreover, although the usage-amount (weight%) of an organic solvent can be variously changed with the kind of organic solvent, 0.2-20 is based on the total weight of the raw material monomer of a water absorbing resin (A). More preferably, it is 0.5-15, Most preferably, it is 1-10.

Moreover, when using water and an organic solvent, the usage-ratio of the organic solvent with respect to water can be changed arbitrarily, but the usage-amount (weight%) of an organic solvent is 20-80 based on the weight of water. More preferably, it is 25-75, Most preferably, it is 30-70.
The surface crosslinking treatment temperature (° C.) is preferably 80 to 200, more preferably 90 to 180, and particularly preferably 100 to 160.

Further, the reaction time (minutes) of the surface crosslinking treatment can be changed depending on the reaction temperature or the like, but is preferably 3 to 60, more preferably 5 to 50, and particularly preferably 10 to 40.
The water absorbent resin (A) or water-containing resin (WA) obtained by surface crosslinking with a surface crosslinking agent may be subjected to additional surface crosslinking with the same type of surface crosslinking agent or a different type of surface crosslinking agent. The amount of the additional surface cross-linking agent used, the processing method, the processing temperature, the processing time, etc. are the same as in the above case.

The shape of the water absorbent resin (A) is not particularly limited, but is preferably granular, more preferably spherical, granular, crushed, needle-like, flake-like, and agglomerated such that these primary particles are fused together. is there.
The size of the water-absorbent resin (A) is not particularly limited, but the particle diameter (90% by weight or more, preferably 93% by weight or more, more preferably 95% by weight or more) of the total weight of the water-absorbent resin (A) ( [mu] m) is preferably 38 to 1180, more preferably 63 to 1000, particularly preferably 106 to 850, and most preferably 150 to 710.

  The size (particle diameter) of the water-absorbent resin (A) was measured using a low-tap test sieve shaker and a sieve specified in JIS Z8801-2000, Perry's Chemical Engineers Handbook 6th Edition (Mac Glow-Hill Book Company, 1984, p. 21) (hereinafter, the particle diameter is measured by this method). That is, JIS standard sieves are arranged in the order of 1000 μm, 850 μm, 710 μm, 500 μm, 425 μm, 355 μm, 250 μm, 150 μm and the saucer from the top, or the order of 425 μm, 300 μm, 250 μm, 150 μm, 125 μm, 75 μm, 45 μm and the saucer from the top, etc. Combine with. About 50 g of measurement sample particles are put in the uppermost stage sieve and infiltrated with a low tap test sieve shaker for 5 minutes. The weight of the sample particles on each sieve and the pan is weighed, the total weight is taken as 100%, and the weight fraction of the particles on each sieve is obtained. The value of each sieve is a logarithmic probability paper {the horizontal axis is the sieve opening ( (Particle diameter) and the vertical axis is plotted as weight fraction}, then a line connecting each point is drawn to obtain a “particle diameter-weight fraction” line. And content of each particle diameter range is computed from this line.

  The viscosity modifier (B1) having a polyvalent metal element means a viscosity modifier that generates polyvalent metal ions when contacted with water, and includes a polyvalent metal element-containing inorganic substance (B11) and a polyvalent metal element-containing organic substance. (B12) is included. The polyvalent metal ions include polyvalent metal complex ions, (B11) includes inorganic complexes, and (B22) includes organic complexes. These also include hydrates.

As the polyvalent metal element-containing inorganic substance (B11), (i) an alkaline earth metal element-containing substance (
ii) a boron group metal element-containing material and (iii) a transition metal element-containing material can be used.
(I) Alkaline earth metal element-containing substance Beryllium element-containing substance (beryllium oxide, beryllium sulfate, etc.), magnesium element-containing substance (magnesium bromide, magnesium chloride, magnesium iodide, magnesium carbonate, magnesium hydrogen phosphate, magnesium hydroxide) , Magnesium nitrate, magnesium oxide, magnesium phosphate, magnesium hydroxide, etc.), calcium element-containing materials (calcium bromide, calcium chloride, calcium iodide, calcium carbonate, calcium nitrate, calcium oxide, calcium sulfate, calcium phosphate, etc.), barium Element-containing substances (barium carbonate, barium chloride, barium chloride, barium bromide, barium iodide, barium carbonate, barium nitrate, barium oxide, barium sulfate, barium phosphate, etc.) and the like.

(Ii) Boron group metal element inclusion Aluminum element inclusion (aluminum chloride, aluminum fluoride, aluminum hydroxide, aluminum nitrate, aluminum oxide, aluminum phosphate, aluminum sulfate, potassium aluminum sulfate, sodium aluminum sulfate and polyaluminum chloride) etc.

(Iii) transition metal element containing iron element containing (iron (II) chloride, iron (III) chloride, iron (III) nitrate, iron (III) oxide, iron (III) phosphate, iron tetrafluoroborate ( III), iron (III) sulfate, iron (II) sulfate, etc.), zinc element-containing materials (zinc bromide, zinc chloride, zinc iodide, zinc oxide, zinc phosphate, etc.), iron complexes (nonacarbonyl iron, etc.) , Cobalt complexes (such as hexaamine cobalt (III) chloride and pentaamine chlorocobalt (III) chloride), ruthenium complexes (such as dibromotetraamine ruthenium (III) nitrate and dichlorotetraamine ruthenium (III) nitrate), and chromium Complexes (such as hexaamine chromium (III) nitrate and trinitrotriamine chromium (III) nitrate).

  Of these polyvalent metal element-containing inorganic substances (B11), from the viewpoint of viscosity change index (VI) and stability, boron group metal element-containing substances and transition metal element-containing substances are preferable, and aluminum element-containing substances are more preferable. And elements containing iron, particularly preferably aluminum sulfate, potassium aluminum sulfate, sodium aluminum sulfate, polyaluminum chloride, iron (III) chloride, iron (III) nitrate, iron (III) oxide and iron (III) sulfate, most preferably Are aluminum sulfate, potassium aluminum sulfate, sodium aluminum sulfate and polyaluminum chloride.

As the polyvalent metal element-containing organic substance (B12), (iv) an organic acid alkaline earth metal salt, (v) an organic acid boron group metal salt, (vi) an organic acid transition metal salt, or the like can be used.
(Iv) Organic acid alkaline earth metal salt Magnesium metal salt (magnesium acetate, magnesium benzoate, magnesium citrate, magnesium lactate, magnesium stearate, magnesium myristate, magnesium benzenesulfonate, etc.), calcium metal salt (calcium gluconate) , Calcium glycerate, calcium lactate, calcium oxalate, calcium stearate, calcium salicylate, calcium dodecylbenzenesulfonate and calcium lauryl sulfate, and barium metal salts (barium gluconate, barium glycerate, barium lactate, barium oxalate) Barium stearate, barium salicylate, barium dodecylbenzenesulfonate and barium lauryl sulfate ester).

(V) Organic acid boron group metal salts Aluminum metal salts (such as aluminum gluconate, aluminum glycerate, aluminum lactate, aluminum oxalate, aluminum stearate, and aluminum salicylate).

(Vi) Organic acid transition metal salt Iron metal salt (such as ammonium iron (III) oxalate, iron (III) citrate, iron (II) gluconate, iron (II) lactate and iron (II) oxalate)), zinc Metal salts (such as zinc acetate, zinc benzoate, zinc gluconate, zinc lactate and zinc stearate), cobalt complexes (such as hexaglycinatocobalt (III) chloride and hexaglycinatocobalt (III) sulfate), ruthenium complexes (Diacetylacetonatotetrachlororuthenium (II) chloride and tris (triphenylphosphine) ruthenium (II) chloride), chromium complexes (tri (ethylenediamine) trinitrochrome (III) chloride and tri (ethylenediamine) trichlorochrome (III) nitrate, etc.).

  Of these polyvalent metal element-containing organic substances (B12), organic acid boron group metal salts and organic acid transition metal salts are preferable, aluminum metal salts and iron metal salts are more preferable, and aluminum gluconate and aluminum glycerate are particularly preferable. Aluminum lactate, iron (III) citrate, iron (III) gluconate and iron (III) lactate.

The viscosity modifier (B2) having at least two ionic groups is an anionic group {carboxyl (—COOH) group, carboxylate (—COO ⁻ ) group, sulfo (—SO ₃ H) group, sulfonate (— SO ₃ ⁻ ) group, phosphono group (—PO (OH) ₂ ) and phosphonate group (—PO (OH) O ⁻ ) etc.} and / or cationic group {quaternary ammonio (—NR ₃ ⁺ ) group etc.} It means a viscosity modifier having at least two. The ionic group (anionic group, cationic group) means a group that becomes a group containing ions (anions, cations) by contact with water or the like. R represents an organic group having 1 to 20 carbon atoms, alkyl having 1 to 4 carbon atoms which may contain a hetero atom, alkenyl having 2 to 4 carbon atoms which may contain a hetero atom, and carbon which may contain a hetero atom. Including aryl of formula 6-10.
Examples of the alkyl having 1 to 4 carbon atoms which may contain a hetero atom include methyl, ethyl, isopropyl, t-butyl, methoxyethyl, nitroethyl and hydroxyethyl.
Examples of the alkenyl having 2 to 4 carbon atoms which may contain a hetero atom include vinyl, 1-propenyl, 2-propenyl, 3-butenyl, 2-isobutenyl, 2-propenyloxymethyl, methoxyvinyl and vinyloxyethyl. .
Examples of the aryl which may contain a hetero atom include phenyl, tolyl, hydroxyphenyl, methoxyphenyl, benzyl, naphthyl, nitrophenyl, chlorophenyl and hydroxynaphthyl.
As the viscosity modifier (B2) having at least two ionic groups, natural compounds (B21), semi-synthetic polymer compounds (B22), synthetic polymer compounds (B23), and the like can be used.

As the natural compound (B21), compounds existing in the living body of animals or plants are used, and alginic acid, gelatin, soy protein and salts of these compounds are included. Here, the salt means an alkali metal (sodium, potassium and lithium) salt, an alkaline earth metal (calcium and magnesium salt, etc.) salt, and the like (hereinafter, the salt is the same unless otherwise noted).
Of these natural compounds (B21), alginic acid and its salt are preferred.

As the semi-synthetic polymer compound (B22), a polymer compound obtained by chemical treatment (water solubilization) of a polymer compound (starch, cellulose, etc.) existing in the living body of an animal or a plant can be used. Treatment (water solubilization) includes oxidation, esterification {reaction of hydroxyl groups such as cellulose with acids (sulfuric acid, phosphoric acid and organic acids (succinic acid) etc.)}, etherification {hydroxyl groups such as cellulose and ethylene oxide. Or reaction with metal alkoxide (such as sodium methoxide and potassium ethoxide) or halide (such as sodium monochloroacetate), and cross-linking {hydroxyl group such as starch and polyvalent epoxide (such as ethylene glycol diglycidyl ether) Reaction etc.} etc. are mentioned, A publicly known method etc. are applicable in any case.
Examples of the semi-synthetic polymer compound (B22) include oxidized starch, sulfated starch, phosphate esterified starch, succinate esterified starch, sulfate esterified cellulose, phosphate esterified cellulose, succinate esterified cellulose, and carboxymethyl cellulose. , Hydroxyethyl cellulose, starch and polyethylene glycol (number average molecular weight 400) diglycidyl ether and salts thereof.

As the synthetic polymer compound (B23), an addition polymerization type synthetic compound (B231), a condensation polymerization type synthetic compound (B232) and the like can be used.
The addition polymerization type synthetic compound (B231) includes a compound that becomes a compound having an ionic group by performing a hydrolysis treatment after polymerization. The hydrolysis treatment can be performed by a known method.
Examples of the addition polymerization type synthetic compound (B231) include compounds having a structure that can be produced by radical polymerization, anionic polymerization and / or cationic polymerization using the ionic monomer (m1) as an essential constituent unit. In addition, the compound of the structure which can be manufactured by chemical-processing (water solubilization) another monomer (m2) is also contained.
The ionic monomer (m1) can be copolymerized with another monomer (m2).

  As the ionic monomer (m1), known monomers can be used, including a carboxyl group-containing vinyl monomer (m11), a sulfo group-containing vinyl monomer (m12), a quaternary ammonio group-containing vinyl monomer (m13), and A vinyl monomer (m14) having a group that becomes an ionic group by hydrolysis can be used.

As the carboxyl group-containing vinyl monomer (m11), a C2-C6 vinyl monomer having a carboxyl group can be used, and examples thereof include acrylic acid, methacrylic acid, maleic acid, fumaric acid, itaconic acid, and salts thereof. .
As the sulfo group-containing vinyl monomer (m12), a vinyl monomer having 2 to 10 carbon atoms having a sulfo group can be used. Vinyl sulfonic acid, allyl sulfonic acid, styrene sulfonic acid, 2-acrylamido-2-methylpropane sulfonic acid , 2-hydroxy-3-butenesulfonic acid and salts thereof.
As the quaternary ammonio group-containing vinyl monomer (m13), trialkylammonioalkyl (meth) acrylate having 4 to 20 carbon atoms can be used, and trimethylammonioethyl (meth) acrylate chloride, trimethylammoniopropyl bromide ( (Meth) acrylate etc. are mentioned, Trimethylammoniostyrene etc. can also be used.
Examples of the group that becomes an ionic group by hydrolysis include an alkyl (C 1-6) oxycarbonyl (—COOR: R is an organic group having 1 to 20 carbon atoms which may contain a hetero atom) group, a cyano group (—CN ), A carbamoyl (—CONH ₂ ) group, a 3-oxo-2-oxapropylene (—COOCO—) group, and the like.
Examples of the vinyl monomer (m14) having a group that becomes an ionic group by hydrolysis include an alkyloxycarbonyl group-containing vinyl monomer (m141), a cyano group-containing vinyl monomer (m142), a carbamoyl group-containing vinyl monomer (m143), and 3- An oxo-2-oxapropylene group-containing vinyl monomer (m144) or the like can be used.
As the alkyloxycarbonyl group-containing vinyl monomer (m141), a vinyl monomer having 4 to 10 carbon atoms is used. Methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, butyl acrylate, hexyl methacrylate And glycidyl methacrylate.
As the cyano group-containing vinyl monomer (m142), a vinyl monomer having 3 to 20 carbon atoms is used, and examples thereof include acrylonitrile, methacrylonitrile, and cyanostyrene.
As the carbamoyl group-containing vinyl monomer, a vinyl monomer having 3 to 20 carbon atoms is used, and examples thereof include acrylamide, methacrylamide and carbamoylstyrene.
As the 3-oxo-2-oxapropylene group-containing vinyl monomer, a vinyl monomer having 4 to 20 carbon atoms is used, and examples thereof include maleic anhydride, citraconic anhydride, and phthalic anhydride.

  Among these ionic monomers (m1), a carboxyl group-containing vinyl monomer (m11), a quaternary ammonio group-containing vinyl monomer (m13), and a vinyl monomer (m14) having a group that becomes an ionic group by hydrolysis. More preferably, a carboxyl group-containing vinyl monomer (m11) and a quaternary ammonio group-containing vinyl monomer (m13), particularly preferably a carboxyl group-containing vinyl monomer (m11), most preferably acrylic acid, methacrylic acid, maleic acid, fumar Acids, itaconic acid and their salts.

  As the other monomer (m2), known monomers can be used, such as alkylene (2 to 8 carbon atoms) oxide (m21), unsaturated alcohol (m22), unsaturated amine (m23), aliphatic. Unsaturated hydrocarbon (m24), aromatic unsaturated hydrocarbon (m25), etc. can be used.

Examples of the alkylene (C2-8) oxide (m21) include ethylene oxide, propylene oxide, butylene oxide, tetrahydrofuran, and styrene oxide.
As unsaturated alcohol (m22), a C3-C30 vinyl monomer containing a hydroxyl group can be used, and α-hydroxyacrylic acid and its salt, hydroxyethyl acrylate, hydroxypropyl acrylate, hydroxyethyl methacrylate, Examples thereof include hydroxypropyl methacrylate, ethylene oxide 10 mol adduct of acrylic acid, ethylene oxide 5 mol propylene oxide 3 mol block adduct of acrylic acid and vinyl alcohol (vinyl acetate is hydrolyzed after polymerization).
As the unsaturated amine (m23), an amine monomer having 7 to 10 carbon atoms can be used, and examples thereof include dimethylaminoethyl acrylate and dimethylaminopropyl methacrylate.
As the aliphatic unsaturated hydrocarbon (m24), an aliphatic unsaturated hydrocarbon having 2 to 10 carbon atoms can be used, and styrene, propylene, 1-butene, 2-butene, isobutylene, cyclopentene, butadiene, cyclopentadiene, and the like. Examples include acetylene.
As the aromatic unsaturated hydrocarbon (m25), an aromatic unsaturated hydrocarbon having 6 to 10 carbon atoms can be used, and examples thereof include styrene, chlorostyrene and vinyltoluene.

  Among the other monomers (m2), alkylene oxide (m21) and unsaturated alcohol (m22) are preferable, more preferably (m22), particularly preferably hydroxypropyl acrylate, hydroxyethyl methacrylate, hydroxypropyl methacrylate. , Ethylene oxide 10 mol adduct of acrylic acid and ethylene oxide 5 mol propylene oxide 3 mol block adduct of acrylic acid.

When the water-soluble monomer (m1) and the other monomer (m2) are copolymerized, the copolymerization ratio (m1 / m2) is preferably (98/2) to (2/98), It is more preferably (95/5) to (10/90), particularly preferably (90/10) to (20/80), and most preferably (85/15) to (40/60). Within this range, the liquid resistance of the viscous liquid excrement is further improved.
The number average molecular weight (Mn) of the addition polymerization type synthetic compound (B231) is preferably 5 to 10 million, more preferably 1000 to 1 million, particularly preferably 1500 to 500,000, and most preferably 2000 to 100,000. Within this range, the liquid resistance of the viscous liquid excrement is further improved.

  As addition polymerization type synthetic compounds (B231) obtained using these monomers, polyacrylic acid (number average molecular weight 2000 to 3 million), polyacrylic acid soda (number average molecular weight 2000 to 3 million), acrylamide-acrylic Acid copolymer (molar ratio = 3: 1, number average molecular weight 10,000-2 million), ethylene-maleic anhydride copolymer (molar ratio 1: 1, number average molecular weight 10,000-5 million), styrene-acrylic Examples include acid copolymers (molar ratio 1: 3, number average molecular weight 10,000 to 5,000,000), polymethacrylic acid (number average molecular weight 2,000 to 4,000,000), and the like.

As the condensation polymerization type synthetic compound (B232), an acid and / or an acid anhydride (m3) and an alcohol and / or an amine (m4) are produced by a polycondensation reaction such as esterification and / or amidation. Polymers having a structure to obtain can be used.
As the acid and / or acid anhydride (m3), known ones can be used, such as monovalent carboxylic acid (m31), polyvalent carboxylic acid (anhydride) (m32), and inorganic acid (m33). Can be used.
As monovalent carboxylic acid (m31), C1-C20 monovalent carboxylic acid etc. can be used, formic acid, acetic acid, propionic acid, myristic acid, stearic acid, linoleic acid, linolenic acid, oleic acid glycolic acid, lactic acid And tartaric acid.

As the polyvalent carboxylic acid (anhydride) (m32), polyvalent (2-4) carboxylic acid having 1 to 20 carbon atoms can be used, and (anhydrous) phthalic acid, isophthalic acid, terephthalic acid, (anhydrous) Succinic acid, adipic acid, azelaic acid, sebacic acid, tetrahydro (anhydrous) phthalic acid, hexahydro (anhydrous) phthalic acid, (anhydrous) maleic acid, fumaric acid, itaconic acid, (anhydrous) trimellitic acid and (anhydrous) pyromellitic An acid etc. are mentioned.
Examples of the inorganic acid (m33) include sulfuric acid, monomethyl sulfuric acid, and phosphoric acid.

  Of the acid and / or anhydride (m3), polyvalent carboxylic acid (anhydride) (m32) is preferable, and (anhydrous) succinic acid, adipic acid, azelaic acid, sebacic acid, (anhydrous) maleic acid, Fumaric acid and itaconic acid, particularly preferably (anhydrous) succinic acid, adipic acid, fumaric acid and itaconic acid.

As the alcohol and / or amine (m4), known ones can be used. Monohydric alcohol (m41), polyhydric alcohol (m42), monohydric amine (m43), polyhydric amine (m44), alkylene oxide of alcohol An adduct (m45), an alkylene oxide adduct of amine (m46), an alkylene oxide adduct of carboxylic acid, and the like can be used.
As monohydric alcohol (m41), C1-C20 monohydric alcohol etc. are used, methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 1-pentanol, 1-hexanol, cyclohexanol. , 2-ethylhexyl alcohol, 1-hexadecanol and the like.

  As the polyhydric alcohol (m42), a polyhydric (2 to 4 valent) alcohol having 1 to 30 carbon atoms or the like is used. Ethylene glycol, propylene glycol, 1,3-butylene glycol, 1,6-hexanediol, diethylene glycol , Dipropylene glycol, neopentyl glycol, triethylene glycol, glycerin, diglycerin, tetraglycerin, trimethylolpropane, sorbitol, penterythritol and dipentaerythritol.

As the monovalent amine (m43), a monovalent amine having 1 to 50 carbon atoms is used, and methylamine, ethylamine, hexylamine, ethanolamine, stearylamine, ralrylamine, triethylamine, diethanolamine, triethanolamine and dicyclohexylamine are used. Etc.
As the polyvalent amine (m44), a polyvalent (2-4) amine having 1 to 50 carbon atoms is used, and examples thereof include ethylenediamine, diethylenetriamine, triethylenetetramine, urea, and melamine.

  As the alkylene oxide adduct (m45) of alcohol, an alkylene (carbon number 2 to 4) oxide adduct (addition number 1 to 30 mol) of a monohydric alcohol (m41) or a polyhydric alcohol (m42), and the like are used. Examples include methanol ethylene oxide 10 mol adduct, pentaerythritol ethylene oxide 20 mol adduct, butanol ethylene oxide 20 mol propylene oxide 10 mol block adduct, and the like.

  As the alkylene oxide adduct (m46) of amine, an alkylene (carbon number 2 to 4) oxide adduct (addition number 1 to 30 mol) of a monovalent amine (m43) or a polyvalent amine (m44) is used, Examples include methylamine ethylene oxide 12 mol adduct and ethylenediamine 12 mol propylene oxide 4 mol block addition product of ethylenediamine.

  Examples of the alkylene oxide adduct (m47) of carboxylic acid include alkylene (carbon number 2 to 4) oxide adduct (addition number 1 to 30 mol) of monovalent carboxylic acid (m31) or polyvalent carboxylic acid (m32). Examples thereof include ethylene oxide 12 mol adduct, ethylene oleate 30 mol adduct, and the like.

  Of the alcohols and / or amines (m4), polyhydric alcohols (m42), alkylene oxide adducts of alcohols (m45) and alkylene oxide adducts of carboxylic acids (m47) are preferred, and (m42) and (m45) are more preferred. ), Particularly preferably (m45).

The use ratio (m3 / m4) of the acid and / or acid anhydride (m3) to the alcohol and / or amine (m4) is preferably (90/10) to (10/90), more preferably (80 / 20) to (20/80), particularly preferably (70/30) to (30/70), and most preferably (60/40) to (40/60). Within this range, the liquid resistance of the viscous liquid excrement is further improved.
The number average molecular weight (Mn) of the condensation polymerization type synthetic compound (B232) is preferably 200 to 1,000,000, more preferably 500 to 300,000, particularly preferably 1,000 to 100,000, and most preferably 2000 to 30,000. Within this range, the liquid resistance of the viscous liquid excrement is further improved.

  As a condensation polymerization type synthetic compound (B232) obtained by using these acids and / or (m3) and alcohol and / or amine (m4), a polyester composed of a 20-mol adduct of glycerin ethylene oxide and succinic acid ( Number average molecular weight 2000 to 100,000), polyester composed of sorbitol and maleic acid (number average molecular weight 2000 to 100,000), polyester composed of adipic acid and polyethylene glycol (number average molecular weight 200 to 5000) (number average molecular weight 1000 to 1000) 100,000), acetic acid triester of pentaerythritol ethylene oxide 10 mol adduct, stearic acid diester of sorbitol, and the like.

  The solubility (25 ° C., g / 100 g water) in water of the viscosity modifier (B1) having a polyvalent metal element and the viscosity modifier (B2) having at least two ionic groups is preferably 0.01 or more, More preferably, it is 0.1 or more, more preferably 1 or more, particularly preferably 2 or more, and most preferably 5 or more. Within this range, the liquid resistance of the viscous liquid excrement is further improved.

  The viscosity change index (VI) of the viscosity modifier (B1) having a polyvalent metal element and the viscosity modifier (B2) having at least two ionic groups is preferably 1.5 to 800, more preferably 1. It is 7 to 600, particularly preferably 1.9 to 500, more particularly preferably 2.1 to 400, and most preferably 2.3 to 300. Within this range, when the absorbent of the present invention is applied to an absorbent article, the liquid resistance of the viscous liquid excrement is further improved.

  Viscosity change index (VI) is artificial soft stool {deionized water: sodium carboxymethylcellulose (number average molecular weight 44000, etherification degree 0.7, for example, CMC Daicel 1110, manufactured by Daicel Industries Ltd.) = Weight ratio 96: 4} It means the ratio of the viscosity of the mixture of artificial loose stool and viscosity modifier to the viscosity, and is measured as follows. Here, the degree of etherification indicates the degree of substitution of the three hydroxyl groups per cellulose unit with carboxymethyl groups. When all the hydroxyl groups are substituted with carboxymethyl groups, the degree of etherification is 3.0.

<Measurement method of viscosity change index (VI)>
Artificial soft stool (deionized water: carboxymethylcellulose = 96: 4) and a 20 wt% aqueous solution of a viscosity modifier (20.0 g if not soluble in water) were uniformly mixed to obtain a mixture. After that, the viscosity (VA, 25 ± 0.5 ° C.) of this mixture was determined in accordance with JIS K7117-1 (1999) (Measurement method of viscosity with SB type viscometer, SB4 spindle, rotation speed 12 rpm). {For example, a BL type viscometer (manufactured by Toki Sangyo Co., Ltd.), rotor No. 4, 12 revolutions / minute} is measured (mPa · s), and a viscosity change index is calculated from the following equation.
In addition, (VB) is the viscosity (mPa · s) of artificial stool measured by exactly the same operation as above except that no viscosity modifier is mixed.

The content (% by weight) of the viscosity modifier (B1) having a polyvalent metal element and / or the viscosity modifier (B2) having at least two ionic groups is based on the weight of the water absorbent resin (A). 0.005 to 50 is preferable, more preferably 0.2 to 40, particularly preferably 0.5 to 20, more particularly preferably 0.8 to 10, and most preferably 1 to 7.5. Within this range, when the absorbent of the present invention is applied to an absorbent article, the liquid resistance of the viscous liquid excrement is further improved.
When both the viscosity modifier (B1) having a polyvalent metal element and the viscosity modifier (B2) having at least two ionic groups are contained, the content weight ratio (B1 / B2) is (2 / 98) to (98/2), more preferably (5/95) to (95/5), particularly preferably (10/90 to 90/10), and even more preferably (15/85) to (85/15), most preferably (20/80) to (80/20).

There is no particular limitation on the content of the water absorbent resin (A) and the viscosity modifier (B1) having a polyvalent metal element and / or the viscosity modifier (B2) having at least two ionic groups, (B1) and / or (B2) may be present on the surface and / or inside of (A), and may be present uniformly or non-uniformly. (B1) and / or (B2) are preferably present on at least the surface of (A).
Further, (B1) and / or (B2) may be either liquid or solid, and in the case of solid, the shape is not particularly limited, but is preferably granular, more preferably spherical, granular, crushed , Needles, flakes, and agglomerates such that these primary particles are fused together. In this case, the size of (B1) and / or (B2) is not particularly limited, but is 90% by weight or more (preferably 93% by weight or more, more preferably 95% by weight or more) of the total weight. The diameter (μm) is preferably 38 to 850, more preferably 63 to 710, particularly preferably 106 to 500, and most preferably 150 to 300 or less.

  The absorbent of the present invention includes, for example, a water-absorbing resin (A), a viscosity modifier (B1) having a polyvalent metal element and / or a viscosity modifier (B2) having at least two ionic groups. If it contains, there is no restriction | limiting in a manufacturing method, (1) The method of mixing and processing by adding (B1) and / or (B2), including (a spray etc. The same also hereafter), stirring (A). (2) In advance, (B1) and / or (B2) is added and mixed at a high concentration to (A) to prepare a master batch, and a predetermined addition amount as (B1) and / or (B2) A method of adding a master batch to (A), mixing and processing, etc. is mentioned.

  The viscosity modifier (B1) having a polyvalent metal element and / or the viscosity modifier (B2) having at least two or more ionic groups are solid (lumps and powders) and liquid (emulsified liquid, dispersion liquid and Any form of (solution) can be added.

When adding the viscosity modifier (B1) having a polyvalent metal element and / or the viscosity modifier (B2) having at least two ionic groups in a liquid form to the absorbent resin (A), Water and / or volatile solvents can be used.
The volatile solvent preferably has a vapor pressure (mmHg) of 17.5 to 700 at 20 ° C., more preferably 20 to 600, and particularly preferably 30 to 500.
Such volatile solvents include alcohols (such as methanol, ethanol and isopropyl alcohol), hydrocarbons (such as hexane, cyclohexane and toluene), ethers (such as diethyl ether and tetrahydrofuran), ketones (such as acetone and methyl ethyl ketone), and esters. (Ethyl acetate, isopropyl acetate, diethyl carbonate and the like) and the like.
When water and / or a volatile solvent is used, the amount used (% by weight) is determined by the viscosity modifier (B1) having a polyvalent metal element and / or a viscosity modifier having at least two or more ionic groups. Based on the weight of (B2), 1-900 are preferable, More preferably, it is 2-700, Most preferably, it is 3-400. Within this range, the liquid resistance of the viscous liquid excrement is further improved.
In addition, when using both water and a volatile solvent, the usage-amount (weight%) of water is preferable 1-99 based on the total weight of water and a volatile solvent, More preferably, it is 5-95, Most preferably Is 10-90.

  The step of mixing and treating the water absorbent resin (A) with a viscosity modifier (B1) having a polyvalent metal element and / or a viscosity modifier (B2) having at least two ionic groups is an aqueous polymerization process. In the case, immediately before the polymerization step, immediately after the polymerization step, immediately before the dehydration step (step of dehydrating to a water content of around 10% by weight), during the dehydration step, immediately after the dehydration step, immediately before the pulverization step, during the pulverization step, surface crosslinking treatment step Immediately before, during the surface crosslinking treatment step, immediately after the surface crosslinking treatment, immediately before the drying step (step of drying to a moisture content of 10% by weight or less), during the drying step, after the drying step, etc. Among these, immediately before the dehydration step, immediately after the dehydration step, immediately before the pulverization step, immediately before the surface crosslinking treatment step, during the surface crosslinking treatment step, immediately after the surface crosslinking treatment, immediately before the drying step, during the drying step and after the drying step are preferable, More preferably immediately before the dehydration step, immediately before the pulverization step, immediately before the surface crosslinking treatment step, during the surface crosslinking treatment step, immediately before the drying step, during the drying step and after the drying step, particularly preferably immediately before the dehydration step, immediately before the surface crosslinking treatment step During the surface cross-linking treatment step, immediately before the drying step, during the drying step and after the drying step, more particularly preferably immediately before the dehydration step, immediately before the surface cross-linking treatment step and immediately before the drying step, most preferably immediately before the surface cross-linking treatment step and drying Immediately before the process.

  In the case of reverse phase suspension polymerization, during the polymerization step, immediately after the polymerization step, during the dehydration step (during the step of dehydrating to a water content of about 10% by weight), immediately after the dehydration step, During the process of separating the used organic solvent, immediately before the surface crosslinking treatment process, during the surface crosslinking treatment process, immediately after the surface crosslinking treatment process, immediately before the drying process (process for drying to a moisture content of 10% by weight or less), during the drying process and Examples include after the drying step. Among these, immediately after the polymerization step, during the dehydration step, immediately after the dehydration step, during the step of separating the water absorbent resin obtained by polymerization and the organic solvent used for the polymerization, immediately before the surface cross-linking treatment step, during the surface cross-linking treatment step, Immediately after the surface cross-linking treatment step, immediately before the drying step, preferably during the drying step and after the drying step, more preferably immediately after the dehydration step, during the step of separating the water absorbent resin obtained by polymerization and the organic solvent used for the polymerization, Immediately before the surface crosslinking treatment step, during the surface crosslinking treatment step, immediately after the surface crosslinking treatment step, immediately before the drying step, during the drying step and after the drying step, particularly preferably immediately before the surface crosslinking treatment step, during the surface crosslinking treatment step, immediately before the drying step And in the drying process.

  Especially as an industrial apparatus for mixing and treating the water absorbent resin (A) and the viscosity modifier (B1) having a polyvalent metal element and / or the viscosity modifier (B2) having at least two ionic groups. There is no limit, but conical blender, internal mixer (Banbury mixer), self-cleaning mixer, gear compounder, screw extruder, screw kneader, minced machine, nauter mixer, double arm kneader, V mixer A mechanical mixing device such as a fluidized bed type mixer, a turbulizer, a screw type line blending device, a ribbon mixer and a mortar mixer is preferably used. These can also be used in combination.

  The water absorption capacity (KB, g / g) of the absorbent of the present invention is preferably 30 to 85, more preferably 40 to 80, particularly preferably 45 to 75, and most preferably 50 to 70. Within this range, when the absorbent of the present invention is applied to an absorbent article, the dryness and the resistance to leakage are further improved under normal pressure.

<Measurement method of water absorption magnification (KB)>
A tea bag (20 cm long, 10 cm wide rectangular bag) made of nylon mesh with a mesh size of 63 μm (JIS Z8801-2000) is prepared with a JIS standard sieve (JIS Z8801-2000) to a particle size of 850 to 150 μm (selected) ) 1.000 g of the measured sample was weighed and immersed in 500 ml of physiological saline (0.9 wt% sodium chloride aqueous solution) for 60 minutes. Then, after taking out a tea bag from physiological saline and suspending it for 15 minutes, a weight (a) is measured and a water absorption magnification is computed from following Formula.
However, b is the blank weight which performed the same operation only using the nylon mesh bag. The weight is measured to 4 digits after the decimal point, and the 4th digit is rounded off.

  The water retention amount (HS, g / g) of the absorbent of the present invention is preferably 20 to 70, more preferably 23 to 60, particularly preferably 26 to 55, more particularly preferably 29 to 50, and most preferably 32 to 48. Within this range, when the absorbent of the present invention is applied to an absorbent article, the dryness and the resistance to leakage are further improved under normal pressure.

<Measurement method of water retention amount (HS)>
A tea bag (20 cm long, 10 cm wide rectangular bag) made of nylon mesh with a mesh size of 63 μm (JIS Z8801-2000) is prepared with a JIS standard sieve (JIS Z8801-2000) to a particle size of 850 to 150 μm (selected) ) 1.000 g of the measured sample was weighed and immersed in 500 ml of physiological saline (0.9 wt% sodium chloride aqueous solution) for 60 minutes. Thereafter, the tea bag is taken out from the physiological saline, the weight (c) of the entire nylon mesh bag after centrifugal dehydration at 150 G for 90 seconds is measured, and the water retention amount is calculated from the following equation.
However, d is the blank weight which performed the same operation only using the nylon mesh bag. The weight is measured to 4 digits after the decimal point, and the 4th digit is rounded off.

  The absorption amount under load (KK, g / g) of the absorbent of the present invention is preferably 6 to 40, more preferably 8 to 37, particularly preferably 10 to 34, more particularly preferably 12 to 31, and most preferably. 14-28. Within this range, when the absorbent of the present invention is applied to an absorbent article, the dryness and the resistance to dripping become even better under load.

<Measurement of absorption under load (KK)>
A cylindrical tube (inner diameter: 25.4 mm, length: 35 mm) equipped with a nylon mesh having a mesh size of 63 μm (JIS Z8801-2000) on one side of the opening is vertically set, and a measurement sample (mesh size of 250 to 500 μm is selected). 0.160 g was charged so as to have a uniform thickness, and an acrylic plate (diameter 25 mm, thickness 8 mm) and a weight of 200 g were placed on the measurement sample, and all these weights (e) Measure. Next, a portion of the cylindrical tube (63 μm mesh portion) is immersed for 60 minutes in 25 g of physiological saline in a horizontally installed petri dish (diameter 85 mm), and after lifting, the entire cylindrical tube is weighed (f), The absorption under load (KK) is calculated from the following equation.

Additives can be added to the absorbent of the present invention.
As additives, antiseptics, fungicides, antibacterial agents, antioxidants, ultraviolet absorbers, colorants, fragrances, deodorants, inorganic powders, fibrous materials and the like are used.
Examples of the preservative include preservatives such as salicylic acid, sorbic acid, dehydroacetic acid and methylnaphthoquinone, and bactericides such as chloramine B and nitrofurazone.
Examples of fungicides include butyl p-oxybenzoate.

Examples of the antibacterial agent include benzalkonium chloride salt and chlorhexidine gluconate.
Antioxidants include hindered phenol antioxidants {triethylene glycol-bis- [3- (3-tert-butyl-5-methyl-4-hydroxyphenyl) propionate], 1,6-hexanediol-bis [ 3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate], octadecyl-3- (3,5-di-tert-butyl-4-hydroxyphenylpropionate) and 3,5-di- t-butyl-4-hydroxybenzyl phosphonate-diethyl ester and the like}, amine antioxidant {n-butylamine, triethylamine, diethylaminomethyl methacrylate and the like}, and a mixture of two or more thereof.

  As the ultraviolet absorber, benzotriazole ultraviolet absorber {2- (5-methyl-2-hydroxyphenyl) benzotriazole, 2- (3,5-di-t-butyl-2-hydroxyphenyl) benzotriazole, 2- (3,5-di-t-butyl-2-hydroxyphenyl) -5-chlorobenzotriazole, 2- (3,5-di-t-amyl-2-hydroxyphenyl) benzotriazole, etc.}, triazine ultraviolet absorber {2- (4,6-diphenyl-1,3,5-triazin-2-yl) -5-[(hexyl) oxy] -phenol and the like}, benzophenone ultraviolet absorber {2-hydroxy-4-n-octyl Oxybenzophenone etc.}, oxalic anilide ultraviolet absorber {2-ethoxy-2′-ethyloxalic acid bisanilide etc.} and two or more of these Include mixtures of.

Examples of the colorant include inorganic pigments such as carbon black, titanium oxide, red iron oxide, red lead, rose red, bitumen and ferrite, organic pigments such as azo lake, benzimidazolone and phthalocyanine, and dyes such as nigrosine and aniline. Can be mentioned.
Examples of the fragrance include natural fragrances such as scent, abies oil and turpentine oil, and synthetic fragrances such as menthol, citral, p-methylacetophenone and floral.
Examples of the deodorant include activated carbon, zeolite, silica, flavonoid, and cyclodextrin.

  Inorganic powders include calcium carbonate, kaolin, talc, mica, bentonite, clay, sericite, asbestos, carbon black, glass (powder, fiber and balloon), shirasu, graphite, metal (iron, copper, aluminum, gold, etc.) , Ceramics (alumina, barium titanate, silicon carbide, carbon nitride, etc.), silica, zeolite, asbestos and the like.

The fibrous material is not particularly limited as long as it is fibrous, and natural fibers, artificial fibers and synthetic fibers, mixtures thereof, and regenerated fibers thereof can be used.
Examples of natural fibers include cotton, absorbent cotton, sawdust, straw, grass charcoal, wool, microfibril, bacterial cellulose, hardwood bleached kraft pulp (LBKP), softwood bleached kraft pulp (NBKP), and flats pulp.
Examples of artificial fibers include rayon and acetate.
Synthetic fibers include polyolefin fibers (such as polyethylene fibers, polypropylene fibers and polyethylene / polypropylene composite fibers), polyester fibers (such as polyethylene terephthalate fibers and polyethylene terephthalate / polyethylene isophthalate copolymer composite fibers), and polyolefin / polyester composite fibers (polyethylene). Polyethylene terephthalate composite fiber and polypropylene / polyethylene terephthalate composite fiber), polyamide fiber (polyterephthalic acid ethylenediamide fiber, polyisoterephthalic acid ethylenediamide fiber, polyterephthalic acid propylene diamide fiber, polyisoterephthalic acid propylene diamide fiber, etc.), Polyacrylic fiber (polybutyl acrylate fiber and 2-ethylhexyl polyacrylate fiber, etc.) And polyacrylonitrile fibers.
Of these, natural fibers and synthetic fibers are preferable, and natural fibers are more preferable.

When using additives, the content of additives is not particularly limited, but the content of preservatives, fungicides, antibacterial agents, antioxidants, UV absorbers, fragrances and deodorants (% by weight) Are preferably 0.00001 to 10, more preferably 0.00005 to 5, based on the weight of the water absorbent resin (A).
Moreover, 0.1-25 are preferable based on the weight of a water absorbing resin (A), respectively, respectively, and, as for content (weight%) of a coloring agent, an inorganic powder, and a fibrous material, 0.2-15 are more preferable. It is.

The absorbent of this invention is suitable as a material which comprises the absorbent article excellent in absorption of a viscous liquid.
Sanitary goods are typical of absorbent articles, such as disposable diapers (children's disposable diapers and adult disposable diapers), napkins (sanitary napkins, etc.), vomit-absorbing etiquette bags, paper towels, pads (patents for incontinence) And an underpad for surgery), a pet sheet (such as a pet urine absorbing sheet and a heat retaining sheet).
In addition to sanitary goods, various household and industrial absorbent sheets (freshness-maintaining sheets, drip absorbent sheets, paddy rice seedling sheets, concrete curing sheets, water running prevention sheets such as cables, etc.) and the like can be mentioned.
Of these, the absorbent of the present invention is particularly suitable for disposable diapers, pads and sanitary napkins.

An absorptive article distributes an absorber which uses an absorber as an essential constituent.
As a method for obtaining this absorbent body, (1) a method in which the absorbent of the present invention and a fibrous material are simultaneously mixed and stacked in an air stream, and (2) an absorbent of the present invention and the fibrous material are mixed in advance. A method of stacking in an air stream, (3) a method of stacking the absorbent of the present invention on a fibrous material, and further stacking a fibrous material, and (4) an absorbent of the present invention And a fibrous material are mixed at the same time in an air stream, stacked, processed by a known method using a known adhesive, and processed into a sheet.
Among these methods, the methods (1) and (2) are preferable, and the method (1) is more preferable. In addition, there is no limitation in particular about the apparatus used for these methods, A normal apparatus can be used and a drum forming apparatus etc. are mentioned.

The basis weight of the absorbent of the present invention contained in the absorber {the content of the absorbent per unit area of the absorber (g / m ² )} is preferably 10 to 1000, more preferably 20 to 900, particularly preferably. Is 30 to 800, most preferably 40 to 700 g / m ² or more.
In addition, when applying the absorber of this invention to sanitary goods, 10-400 are preferable, as for the fabric weight (g / m < ² >) of the absorbent of this invention, More preferably, it is 20-300, Most preferably, it is 30-250. Most preferably, it is 40-200.
When the weight per unit area is within this range, the water retention amount of the absorbent body becomes higher, and when applied to an absorbent article, the more excellent resistance to leakage of viscous liquid excreta is exhibited.

As for the fabric weight (g / m < ² >) of the fibrous material contained in an absorber, 10-1000 are preferable, More preferably, it is 20-900, Most preferably, it is 30-800, Most preferably, it is 40-700.
In addition, when applying the absorber of this invention to sanitary goods, 10-400 are preferable, as for the fabric weight (g / m < ² >) of the absorbent of this invention, More preferably, it is 20-300, Most preferably, it is 30-250. Most preferably, it is 40-200.
When the weight per unit area is within this range, when applied as an absorbent article, the more excellent resistance to leakage of viscous liquid excreta is exhibited.

The content (% by weight) of the absorbent of the present invention is preferably 20 to 99, more preferably 22 to 98, even more preferably 24 to 95, particularly based on the total weight of the absorbent and the fibrous material. Preferably 26 to 93, more particularly preferably 28 to 91, next preferably 30 to 89, then further preferably 32 to 87, more preferably 35 to 85, next particularly preferably 37 to 83, next. Is more preferably 40 to 81, most preferably 42 to 80. Within this range, more excellent resistance to viscous liquid-like excrement is exhibited.
The thickness (mm) of the absorber is preferably 0.5 to 5, more preferably 1 to 4.5, still more preferably 1.5 to 4, particularly preferably 2 to 3.5, and most preferably 2. 5-3. Within this range, the absorbent article can be made thinner without lowering the absorption performance, and uncomfortable feeling and uncomfortable feeling when using the absorbent article can be reduced.

The liquid resistance of viscous liquid excreta can be quantified by measuring the diffusion distance (BK) when artificial stool (deionized water: carboxymethylcellulose = weight ratio 96: 4) is absorbed. it can. The smaller the value of (BK), the better the resistance to leakage.
The diffusion distance (BK, cm) when absorbing artificial stool of an absorbent article containing an absorbent comprising the absorbent of the present invention as an essential constituent is preferably 2 to 20, more preferably 3 to 3. 19, particularly preferably 4-18, most preferably 5-17.

<Method of measuring diffusion distance (BK) when artificial stool is absorbed>
Cut the central part of the measurement sample to a size of 10 × 30 cm, and place it flat on a plate inclined at 15 degrees with one end of 10 cm on top and the other end of 10 cm on the bottom (cut absorbency Do nothing on the edge of the article).
Artificial soft stool (deionized water: carboxymethylcellulose = weight ratio) 3 cm from one upper end of the measurement sample (ie 27 cm from the other lower end) and 5 cm from either end of 10 cm (in the range of about 3 cm ² ) 96: 4) 50 g is injected at a rate of 50 g / min using a glass cylinder having an inner diameter of 2 cm. The liquid injection is performed from a location about 1 cm away from the surface of the absorbent article, and it is allowed to fall naturally without applying pressure.
At the end of the 50 g injection of artificial stool, 10 seconds later, the length from the uppermost end to the lowest end of the artificial stool is measured. The measurement is performed three times, the average value is obtained, and it is defined as the diffusion distance (BK, cm) of the artificial stool. All measurements are performed in an atmosphere of 25 ± 3 ° C. and 60 ± 5 RH%.

As the structure of the absorbent article, a liquid permeable top sheet (OS) is arranged on the uppermost layer, a liquid impermeable back sheet (US) is arranged on the lowermost layer, and an intermediate layer is made of an absorbent and a fibrous material. Structure (K1) in which the configured absorbent body (one layer) is arranged, a liquid permeable top sheet (OS) is arranged in the uppermost layer, and a liquid non-permeable back sheet (US) is arranged in the lowermost layer. 2-4 layers of the same absorbent body as in the case of (K1) are stacked as a layer, and a laminated absorbent body is disposed, and one or more liquid permeable intermediate sheets are provided between the absorbent bodies of the laminated absorbent body as necessary. In the structure (K2) provided with (CS) and the structure (K1) or (K2), at least one liquid-permeable intermediate between the uppermost layer and the intermediate layer and / or between the intermediate layer and the lowermost layer The structure (K3) etc. which has arrange | positioned the sheet | seat (CS) are mentioned.
Among these, (K3) is preferable from the viewpoint of leakage of the absorbent from the absorbent article.

  As a specific example of the absorbent article, a paper diaper will be described. A liquid-permeable top sheet (OS) is disposed on the surface of the absorbent article, and a liquid-impermeable back sheet (US) is disposed on the back surface. If necessary, a liquid permeable intermediate sheet (CS) is further stacked on the upper and lower portions of the absorber layer, and a paper diaper or the like is finished by installing a gather or a tape for mounting on the human body.

  As the liquid-permeable surface sheet (OS) used for the absorbent article, water, seawater, muddy water, urine, feces, menstrual blood and other absorbed materials absorbed by the absorbent article can easily penetrate and absorb its thickness. Although it will not specifically limit if it is absorbed by a body layer, From the paper (Japanese paper, tissue paper, etc.) made from a cellulose fiber, the nonwoven fabric made from a thermoplastic resin, a woven fabric or a knitted fabric, and a thermoplastic resin etc. A perforated film or the like to be made is preferably used. In addition, as for the hole diameter (mm) of a perforated film, 0.01-300 are preferable, More preferably, it is 0.02-200, Most preferably, it is 0.03-100.

Thermoplastic resins include polyolefin (polyethylene, polypropylene and polyethylene / polypropylene copolymer, etc.), polyester (polyethylene terephthalate and polyethylene terephthalate / polyethylene isophthalate copolymer, etc.), polyolefin / polyester copolymer (polyethylene / polyethylene terephthalate copolymer). Polymer and polypropylene / polyethylene terephthalate copolymer, etc.), polyamide (polyterephthalic acid ethylenediamide, polyisoterephthalic acid ethylenediamide, polyterephthalic acid propylene diamide, polyisoterephthalic acid propylene diamide fiber, etc.), polyacrylic (polyacrylic acid) Butyl fiber and polyethyl 2-ethylhexyl acrylate fiber) and polyacrylonitrile fiber.
Of these liquid-permeable surface sheets (OS), non-woven fabrics, woven fabrics and knitted fabrics made from thermoplastic resins are preferred, more preferred are non-woven fabrics made from thermoplastic resins, and particularly preferred are polyolefin resins, polyester resins or polyolefins. -Nonwoven fabric made from polyester copolymer.
Although it does not specifically limit as thickness (micrometer) of a liquid-permeable surface sheet (OS), 5-5000 are preferable, From a viewpoint of the diffusibility of a to-be-absorbed material, the thickness of an absorbent article, and a softness | flexibility, it is further. Preferably it is 10-1000, Most preferably, it is 20-750, Most preferably, it is 30-500.

The liquid non-permeable back sheet (US) used for the absorbent article is not particularly limited as long as the viscous liquid excretion absorbed by the absorbent article can prevent the exudation to the back face. A sheet made of the above-described thermoplastic resin or the like is used.
Of these, a sheet made of polyolefin is preferable, a sheet made of polyethylene, polypropylene or polyethylene / polypropylene is more preferable, and a sheet made of polyethylene is particularly preferable.
Although it does not specifically limit as thickness (micrometer) of a back surface sheet, 5-5000 are preferable, From a viewpoint of the thickness of an absorbent article, and a softness | flexibility, More preferably, it is 10-1000, Most preferably, it is 20-750, Most preferably, it is 30-500.

As the liquid-permeable intermediate sheet (CS) used as necessary, the same liquid-permeable surface sheet (OS) as that used for the liquid-permeable surface sheet (OS) can be used.
The liquid-permeable intermediate sheet is intended to make it easy for water, seawater, muddy water, urine, feces, menstrual blood and the like to be absorbed into the absorbent article, and to be easily absorbed and diffused into the absorber layer. Is.
The materials and types of gathers and mounting tapes are not particularly limited, and known materials used in conventional absorbent articles can be used.

Hereinafter, the usefulness of the present invention will be described with reference to Examples and Comparative Examples, but the present invention is not limited thereto. Hereinafter, unless otherwise specified, parts means parts by weight, and% means% by weight.
Viscosity improvement index (VI), absorption amount under load (KK), water absorption rate (KB), water retention amount (HS), and diffusion distance (BK) when artificial stool is absorbed are the same as in the above method. And measured.
<Example 1>
A reaction vessel was charged with 81.8 parts of acrylic acid, 0.3 part of N, N′-methylenebisacrylamide and 241 parts of deionized water, and the temperature of the contents was maintained at 1 to 2 ° C. while stirring and mixing.
Next, after flowing nitrogen into the liquid layer of the contents for 30 minutes, under sealing, 1 part of 1% aqueous hydrogen peroxide, 1.2 parts of 0.2% aqueous ascorbic acid solution and 2% 2,2 ′ -2.8 parts of an azobisamidinopropane dihydrochloride aqueous solution was added and mixed to initiate polymerization (about 5 ° C).
The temperature increased with the polymerization and reached about 70 ° C. Subsequently, polymerization was carried out while maintaining the temperature at 70 to 80 ° C for about 8 hours in a sealed state to obtain a water-containing polymer. While this water-containing polymer was kneaded with an internal mixer, 72.7 parts of a 45% aqueous sodium hydroxide solution was added to neutralize 72 equivalent% of carboxyl groups. In addition, the neutralization degree calculated from the acid value measured according to JIS K0113-1997 (using 0.1 N potassium hydroxide aqueous solution as a titrant, potentiometric titration method, inflection point method) is 70.1 equivalent% Met.
Next, it is shredded to a size of 2 to 5 mm with an internal mixer, dried with an air-flowing band dryer under conditions of 150 ° C. and a wind speed of 2.0 m / sec, and then the dried product is pulverized, followed by a standard sieve (JIS Z8801). -2000), and particles having a particle diameter of 150 to 710 μm were prepared by removing particles of 710 μm or more and particles of 150 μm or less.
While maintaining 100 parts of these particles at 50 to 60 ° C. under high speed stirring, ethylene glycol diglycidyl ether (Nagase Chemicals, trade name: Denacol EX810) / water / methanol mixed solution (ethylene glycol diglycidyl ether / water / 9.5 parts of methanol [weight ratio] = 2/30/70) was added, followed by mixing for about 15 minutes while maintaining the temperature at 50 to 60 ° C., and then reacting at 140 ° C. for 40 minutes to obtain a water absorbent resin (a1) Got.
Furthermore, 10.0 parts of a 20% aqueous solution (b11) of aluminum sulfate (viscosity change index (VI) = 20.5) was added to (a1) at 25 ° C. and mixed with an internal mixer. And dried for 30 minutes to obtain the absorbent (1) of the present invention.
The absorbent (1) had an absorption amount under load (KK) of 26 g / g, a water absorption capacity (KB) of 53 g / g, and a water retention amount (HS) of 35 g / g.

<Example 2>
A 20% aqueous solution (b11) of aluminum sulfate was changed to a 5% aqueous solution (b12) of iron (III) chloride (viscosity improvement index (VI) = 55.0) in the same manner as in Example 1 except that Absorbent (2) was obtained.
The absorbent (2) had an absorption amount under load (KK) of 27 g / g, a water absorption capacity (KB) of 53 g / g, and a water retention amount (HS) of 35 g / g.

<Example 3>
A 20% aqueous solution (b11) of aluminum sulfate was changed to a 3% aqueous solution (b21) of polyacrylic acid (number average molecular weight 3000) (viscosity improvement index (VI) = 5) in the same manner as in Example 1 except that The absorbent (3) of the invention was obtained.
The absorbent (3) had an absorption amount under load (KK) of 25 g / g, a water absorption capacity (KB) of 53 g / g, and a water retention amount (HS) of 35 g / g.

<Example 4>
The absorbent (4) of the present invention was obtained in the same manner as in Example 1 except that the 20% aqueous solution of aluminum sulfate (b11) was changed to a 5% methanol solution of aluminum sulfate.
The absorbent (4) had an absorption amount under load (KK) of 27 g / g, a water absorption capacity (KB) of 53 g / g, and a water retention amount (HS) of 35 g / g.

<Example 5>
346.0 parts of 25% aqueous sodium hydroxide solution was added to a mixed liquid of 208 parts of acrylic acid and 13.5 parts of water while cooling. To this solution, 0.1 part of potassium persulfate, 0.02 part of sodium hypophosphite and 0.1 part of ethylene glycol diglycidyl ether (Nagase Chemical Industries, Ltd., trade name: Denacol EX810) were added, A monomer aqueous solution was prepared by adjusting the temperature to 10 ° C.
Next, 624 parts of cyclohexane was placed in a reaction vessel equipped with a stirrer, a reflux condenser, a thermometer, and a nitrogen gas introduction tube, and polyoxyethylene octylphenyl ether phosphate ester (Daiichi Kogyo Seiyaku Co., Ltd., trade name: Ply) Surf A210G) 1.6 parts were added and dissolved, and then nitrogen gas was introduced while stirring.
Next, the reaction vessel was heated to bring the mixture of cyclohexane and the like to 75 ° C., and the above monomer aqueous solution maintained at 5 to 10 ° C. was added dropwise with stirring with nitrogen gas at a substantially constant rate over 60 minutes. At this time, the oxygen concentration in the flask was kept at 10 to 30 ppm. After the introduction of the aqueous monomer solution, the mixture was further stirred for 30 minutes at 75 ° C., and then water was removed by azeotropy with cyclohexane, and the water content of the produced polymer was about 20% (the water content was calculated from the amount of water removed). When the stirring was stopped when the value reached, the polymer particles settled, and the polymer particles and cyclohexane were separated by decantation to obtain polymer particles.
40 parts of the obtained polymer particles (dry basis, 130 ° C. × 30 minutes dry value) and 140 parts of cyclohexane are placed in a reflux apparatus, and glycerin polyglycidyl ether (Nagase Kasei Kogyo Co., Ltd., trade name: Denacol EX314) is added thereto. After adding 3.4 parts of a methanol solution containing 5%, the mixture was heated at 60 ° C. and kept for 30 minutes, and further kept under reflux of methanol / cyclohexane for 30 minutes.
Subsequently, the polymer particles were obtained by filtration and dried under reduced pressure at 80 ° C. to obtain a water absorbent resin (a2). Furthermore, 5.0 parts of (a2) 5% aqueous solution (b22) of acrylic acid-acrylamide (molar ratio = 1: 3, number average molecular weight 40,000, viscosity change index (VI) = 280) at 25 ° C. Was added and mixed with an internal mixer for 20 minutes to obtain the absorbent (5) of the present invention.
The absorbent (5) had an absorption amount under load (KK) of 18 g / g, a water absorption capacity (KB) of 59 g / g, and a water retention amount (HS) of 33 g / g.

<Comparative Example 1>
A comparative absorbent (6) of the present invention was obtained in the same manner as in Example 1 except that the 20% aqueous solution of aluminum sulfate (b11) was changed to deionized water.
The absorbent (6) had an absorption amount under load (KK) of 24 g / g, a water absorption capacity (KB) of 53 g / g, and a water retention amount (HS) of 33 g / g.

<Comparative example 2>
A comparative absorbent (7) of the present invention was obtained in the same manner as in Example 5 except that the 5% aqueous solution (b22) of acrylic acid-acrylamide was changed to deionized water.
The absorbent (7) had an absorption amount under load (KK) of 18 g / g, a water absorption capacity (KB) of 58 g / g, and a water retention amount (HS) of 33 g / g.

Using the absorbents (1) to (5) of Examples 1 to 5 and the absorbents (6) to (7) of Comparative Examples 1 to 2, the absorbent bodies (1) to (5) and the comparison were performed as follows. Absorbers (6) to (7) for use were prepared.
<Manufacture example 1 of absorber (X)>
8 parts of absorbent (1) and 12 parts of Japanese Pharmacopoeia absorbent cotton (manufactured by Kawamoto Sangyo Co., Ltd.) were defibrated by hand about 500 times with mixing until uniform in appearance.
Thereafter, the defibrated mixture is spread to a size of 15 cm × 45 cm, and then pressed at 8 kg / cm ² at 50 ° C. for 30 seconds using a heater plate press machine (model number N4008-00) manufactured by NPA System Co., Ltd. As a result, an absorbent body (1) was obtained.

<Production Examples 2 to 5 and Comparative Production Examples 6 to 7 of the absorber (X)>
Absorbers (2) to (5) and comparative absorbers (6) to (7) were prepared in the same manner as in Production Example 1 except that the absorbent (1) was changed to the absorbents (2) to (7). Obtained.

Using these absorbent bodies (1) to (7), absorbent articles (1) to (5) and comparative absorbent articles (6) to (7) were produced as follows.
<Example 1 of production of absorbent articles>
An absorbent body (1) is placed on a 40 μm-thick polypropylene film (15 cm × 45 cm) as a liquid-impermeable back sheet, and a 100 μm-thick polyethylene terephthalate nonwoven fabric (15 cm × 45 cm) is formed thereon as a liquid-permeable surface sheet. ) Was placed, and then the four sides were hot-pressed with a width of 1 cm to obtain an absorbent article (1).

<Production Examples 2 to 5 and Comparative Production Examples 6 to 7 of Absorbent Article>
Absorbent articles (2) to (5) and comparative absorbent articles (6) to (7) as in Production Example 1 except that the absorbent body (1) is changed to the absorbent bodies (2) to (7). Got.

  About these absorptive articles (1)-(7), the diffusion distance (BK) when artificial stool was absorbed was evaluated, and these results are shown in Table 1.

Absorbent articles (1) to (5) using the absorbent according to the present invention have a short diffusion distance of artificial stool, and show excellent performance in loose stool resistance.
Among these, in particular, the absorbent articles (1) and (5) exhibited extremely excellent moisture resistance.
On the other hand, the absorbent articles (6) to (7) using an absorbent for comparison had a large diffusion distance of artificial soft stool, and the loose resistance of soft stool was insufficient.

The absorbent of the present invention is suitable as a material constituting an absorbent article that also absorbs viscous liquids.
Examples of absorbent articles include sanitary products such as paper diapers (children's diapers and adult paper diapers, etc.), napkins (sanitary napkins, etc.), vomit-absorbing etiquette bags, paper towels, pads (incontinent persons) And a pet sheet (such as a pet urine absorbing sheet and a heat retaining sheet).
In addition to sanitary products, it can also be applied to various household and industrial absorbent sheets (for example, freshness keeping sheets, drip absorbent sheets, paddy rice seedling sheets, concrete curing sheets, and water running prevention sheets such as cables). .
Among these, the absorbent of the present invention is particularly suitable for disposable diapers, pads and sanitary napkins.

Claims (8)

Absorption characterized by comprising a water-absorbing resin (A) and a viscosity modifier (B1) having a polyvalent metal element and / or a viscosity modifier (B2) having at least two ionic groups. Agent. The viscosity change index (VI) of the viscosity modifier (B1) having a polyvalent metal element and / or the viscosity modifier (B2) having at least two ionic groups is 1.5 to 800. Absorbent. The absorbent according to claim 1 or 2, comprising a viscosity modifier (B1) having a polyvalent metal element, wherein the polyvalent metal element is calcium, aluminum and / or iron. It contains a viscosity modifier (B2) having at least two ionic groups, and the ionic groups are carboxyl (—COOH) group, carboxylate (—COO ⁻ ) group and / or quaternary ammonio (—NR _3). The absorbent according to any one of claims 1 to 3, wherein ⁺ : R is an organic group having 1 to 20 carbon atoms. The absorber which becomes as an essential component the absorber and fibrous material in any one of Claims 1-4. The absorbent according to claim 5, wherein the absorbent is contained in an amount of 20 to 99% by weight based on the total weight of the absorbent and the fibrous material. An absorbent article comprising the absorber according to claim 5 or 6. The absorbent article according to claim 7, wherein a diffusion distance (BK) when artificial stool (deionized water: carboxymethylcellulose sodium = weight ratio 96: 4) is absorbed is 2 to 20 cm.