JP2003183528A - Absorbent, absorber and absorptive product using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an absorbent which is resistant to a gel blocking trouble even if it is contained in an amount of 40 wt.% or more based on the total weight of the absorbent and a fibrous material, and to provide an ultrathin absorptive product using the absorbent. <P>SOLUTION: The absorbent comprises a water-absorptive resin (A) and a water-soluble resin (B) having a number average molecular weight of 500 or more and 2,000,000 or less. The water-soluble resin (B) has preferably a solubility parameter of 8.0 or more and 20.0 or less, and is preferably a nonionic resin. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an absorbent, an absorbent body using the same, and an absorbent article.

[0002]

2. Description of the Related Art In recent years, in order to reduce discomfort and discomfort during use of absorbent articles (paper diapers, sanitary napkins, urine absorbing pads, etc.), the absorbent articles have been made thinner. As a thin absorbent article, there is known an absorbent article or the like in which the usage ratio of the absorbent in the absorber to the fibrous material (absorbent / fibrous material) is increased (Japanese Patent Laid-Open No. 08-33).
7726 publication).

[0003]

However, when the content of the absorbent in the absorbent body used in the conventional absorbent article is 40% by weight or more based on the total weight of the absorbent and the fibrous material, The gel blocking phenomenon of the absorbent occurs under normal pressure,
Along with this, the absorption performance deteriorates, and it becomes impossible to exhibit the function as an absorbent article. Therefore, the conventional absorbent cannot meet the demand for further thinning of the absorbent article. That is, the purpose of the present invention is to determine that the content of the absorbent in the absorbent is 4 based on the total weight of the absorbent and the fibrous material.
An object of the present invention is to provide an absorbent that is less likely to cause a gel blocking phenomenon even when the content is 0% by weight or more, and further provide an ultrathin absorbent article using the absorbent.

[0004]

Means for Solving the Problems As a result of intensive studies for achieving the above object, the present inventors have found that a specific absorbent achieves the above object, and arrived at the present invention.
That is, the feature of the absorbent of the present invention is that the water absorbent resin (A)
And the number-average molecular weight of the water-soluble resin (B) is 500 or more and 2,000,000 or less.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION As the water absorbent resin (A), an ordinary water-swellable crosslinked polymer (a) or the like can be used. Examples of the water-swellable crosslinked polymer (a) include (1) to
Examples include the polymer (8). In addition, you may use 2 or more types of these polymers together. (1) JP-B-53-46199 or JP-B-53-
Starch-acrylic acid (salt) graft cross-linked copolymer (a1) described in Japanese Patent No. 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) JP-B-54-30710, JP-A-56-2
Crosslinked polyacrylic acid (salt) (a3) obtained by reverse phase suspension polymerization as described in JP-A-6909 or JP-A-11-5808.

(4) Saponified product (a4) of a copolymer of a vinyl ester and an unsaturated carboxylic acid or its derivative described in JP-A-52-14689 or JP-A-52-27455. (5) JP-A-58-2312 or JP-A-61-3
A copolymer (a5) of acrylic acid (salt) and a sulfo (salt) group-containing monomer described in, for example, Japanese Patent No. 6309. (6) Crosslinked isobutylene-maleic anhydride copolymer (a6) described in U.S. Pat. No. 4,389,513. (7) Hydrolyzate (a7) of starch-acrylonitrile copolymer described in JP-A-46-43995. (8) Crosslinked carboxymethyl cellulose derivative (a8) described in US Pat. No. 4,650,716 and the like.

Of these, starch-acrylic acid (salt) graft copolymer cross-linked products (a
1), crosslinked polyacrylic acid (salt) (a2) obtained by aqueous solution polymerization and crosslinked polyacrylic acid (salt) (a3) obtained by reverse phase suspension polymerization are preferable, and more preferably (a2) and (a3). Is.

Furthermore, the water-absorbent resin (A) can be crosslinked near the surface of the water-absorbent resin (A), if necessary (surface crosslinking treatment). The water-absorbent resin (A) whose surface is cross-linked in this way is preferable because the water-absorption rate is further improved and the absorption amount under a load is increased. Examples of the surface cross-linking agent include, for example, JP-A-59-18.
Polyvalent glycidyl compounds described in JP-A-9103, JP-A-58
-180233 or JP-A-61-16903, polyhydric alcohols, polyhydric amines, polyhydric aziridine and polyhydric isocyanates, JP-A-61-21130.
No. 5, JP-A-61-252212, etc., and JP-A-51-1365.
Polyvalent metals described in JP-A No. 88 or JP-A No. 61-257235 and the like can be mentioned.

Among these surface cross-linking agents, comparison is made with respect to the viewpoint that a water-absorbent resin excellent in both water absorption rate and water absorption under pressure can be obtained by forming a strong covalent bond with a carboxyl (salt) group and the crosslinking reaction. From the viewpoint that it can be carried out at a relatively low temperature and is economical, and the like, polyvalent glycidyl, polyvalent amine and silane coupling agents are preferable, more preferably polyvalent glycidyl and silane coupling agents, and particularly preferably polyvalent glycidyl and silane coupling agents. Valuate glycidyl.

When the surface cross-linking agent is used, the amount of the surface cross-linking agent used can be variously changed depending on the kind of the surface cross-linking agent, the conditions for cross-linking, the target performance, etc., but it is not particularly limited, but the water-absorbing performance From the viewpoint of water-absorbent resin (A)
It is preferably 3% by weight or less, more preferably 2% by weight or less, particularly preferably 1% by weight or less, and more preferably 0.001% by weight or more, based on the total weight of the raw material monomers of It is 0.005% by weight or more, particularly preferably 0.01% by weight or more. Surface cross-linking treatment is
It may be performed at any stage before drying the water-containing resin (WA) containing the water-absorbent resin (A) and water, during drying (WA), and after drying (WA). On the other hand, the stage during the drying of (WA) or after the drying of (WA) is preferable from the viewpoint of easy adjustment of the crosslinking conditions.

As a method for carrying out this surface cross-linking treatment, a conventionally known method can be applied. For example, a mixed solution of a surface cross-linking agent, water and an organic solvent is mixed with a water-absorbent resin (A) or a water-containing resin (WA). However, a method of reacting by heating can be applied. The amount of water used for the surface cross-linking treatment is based on the total weight of the raw material monomers of the water-absorbent resin (A) from the viewpoint of appropriately permeating the surface-crosslinking agent into the water-absorbent resin (A). Is preferably 10% by weight or less, more preferably 8% by weight or less, particularly preferably 7% by weight or less, and 1
It is preferably at least wt%, more preferably 1.5 wt%
More preferably, it is 2% by weight or more.

As the type of organic solvent used in the surface cross-linking treatment, conventionally known hydrophilic solvents can be used. The degree of penetration of the surface cross-linking agent into the water absorbent resin (A), the surface cross-linking agent It can be appropriately selected in consideration of the reactivity and the like, but, for example, hydrophilic organic solvents such as methanol, ethanol, ethylene glycol, propylene glycol and diethylene glycol which are soluble in water are preferable.
Such solvents may be used alone or in combination of two or more. The amount of the organic solvent used can be variously changed depending on the kind of the organic solvent, but is 0.2% by weight based on the total weight of the raw material monomers of the water absorbent resin (A).
Or more, more preferably 0.5% by weight or more,
Particularly preferred is 1% by weight or more, and 20% by weight
The following is preferable, 15% by weight or less is more preferable, and 10% by weight or less is particularly preferable.

The ratio of the organic solvent to water can be changed arbitrarily, but the amount of the organic solvent used is
Based on the weight of water, it is preferably 80% by weight or less, more preferably 75% by weight or less, particularly preferably 70% by weight or less, and preferably 20% by weight or more, more preferably 25% by weight or more, especially It is preferably 30% by weight or more. The temperature of the surface cross-linking treatment is preferably 200 ° C or lower, more preferably 180 ° C or lower, particularly preferably 160 ° C or lower, and preferably 80 ° C or higher, more preferably 90 ° C or higher, and particularly preferably 10 ° C.
It is 0 ° C or higher.

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

The shape of the water absorbent resin (A) is not particularly limited, but it is preferably granular, more preferably spherical, granular,
It is in a crushed form, a needle form, a flaky form, or an agglomerated form in which primary particles of these are fused together. The size of the water absorbent resin (A) is not particularly limited, but 90% of the total weight of the water absorbent resin (A) is used.
The particle diameter of weight% or more (preferably 93 weight% or more, more preferably 95 weight% or more) is preferably 1180 μm or less, more preferably 1000 μm or less, particularly preferably 850 μm or less, most preferably 710 μm or less, and 38 μm. It is preferably not less than 63 μm, more preferably not less than 106 μm, most preferably not less than 150 μm.

The size of the water-absorbent resin (A) is measured by a low tap test sieve shaker and JIS Z8801-2.
Using a sieve defined in 000, the method is described in Perry's Chemical Engineers Handbook 6th edition (MacGlow-Hill Book Company, 1984, p. 21). According to this method.).

The number average molecular weight of the water-soluble resin (B) is 50.
0 or more, preferably 1,000 or more, more preferably 1,500 or more, particularly preferably 2,000 or more, particularly preferably 2,500 or more, most preferably 3,000 or more, and 2 1,000,000 or less, preferably 1,000,000 or less, more preferably 600,000 or less, particularly preferably 20.
It is 50,000 or less, more preferably 100,000 or less, and most preferably 70,000 or less. When the number average molecular weight is within this range, when the absorbent of the present invention is applied to an absorbent article, the dryness and the leak resistance are more likely to be improved under normal pressure. The number average molecular weight (hereinafter, abbreviated as Mn) is calculated by measuring with GPC (gel permeation chromatography).

In the present invention, the water-soluble resin (B) means
It means a resin capable of dissolving at least 2 g in 100 g of water at 25 ° C. The solubility of the water-soluble resin (B) in water (25 ° C., 100 g) is 2 g or more,
Preferably 4 g or more, more preferably 6 g or more, even more preferably 10 g or more, particularly preferably 15 g or more, particularly preferably 20 g or more, most preferably 3
0 g or more, and the upper limit is preferably infinite, but 1
The amount may be less than or equal to 00000 g, and further 10000.
g or less, more preferably 5000 g or less, and even more preferably 2
It may be less than or equal to 000 g, more particularly less than or equal to 1000 g, and even less than or equal to 500 g. When the solubility is in this range, when the absorbent of the present invention is applied to an absorbent article, the dryness and the leakage resistance are more likely to be improved under normal pressure. The solubility in water at 25 ° C is
It can be measured according to the solubility test described in “Encyclopedia of Chemistry 9, edited by Encyclopedia of Chemistry, published by Kyoritsu Shuppan Co., Ltd., p. 399 (1989)” and is contained in a solute saturated aqueous solution at 25 ° C. Mean weight percent of solute.

The solubility parameter of the water-soluble resin (B) is 8.0 or more, preferably 8.3 or more, more preferably 8.5 or more, particularly preferably 8.7 or more, most preferably 9. 0 or more and 20.0 or less, preferably 19.8 or less, more preferably 1
It is 9.5 or less, particularly preferably 16.0 or less, and most preferably 14.0 or less. When the solubility parameter is in this range, when the absorbent of the present invention is applied to an ultrathin absorbent article, the dryness and the leak resistance are more likely to be improved under normal pressure. The solubility parameter is
Fedors method [Poym. Eng. Sci. 14
(2) 152, (1974)].

As the water-soluble resin (B), for example, a natural water-soluble polymer (b1), a semi-synthetic water-soluble polymer (b2), a synthetic water-soluble polymer (b3) or the like can be used.
As the natural water-soluble polymer (b1), a polymer compound existing in the body of animals or plants is used, and examples thereof include starch, cellulose, alginic acid, agar, pectin, caranagin, konjak, arabic gum, casein, gelatin and soybean. Protein etc. are mentioned.

As the semi-synthetic water-soluble polymer (b2), a polymer compound obtained by chemically treating a polymer compound existing in the living body of an animal or a plant can be used. The chemical treatment includes oxidation and esterification. Examples of the treatment include etherification and cross-linking, and in any case, the treatment can be performed by a known method. Examples of the semi-synthetic water-soluble polymer (b2) include oxidized starch, sulfated starch, nitrated starch, phosphated starch, acetic acid esterified starch, succinic acid esterified starch, methylated starch, and hydroxyethyl. Starch, carboxymethylated starch, sulfate esterified cellulose, nitrate esterified cellulose, phosphate esterified cellulose, acetate esterified cellulose, succinate esterified cellulose, methylated cellulose, hydroxyethylated cellulose and carboxymethylated cellulose,
And salts of these compounds. Here, the salt means, for example, an alkali metal salt such as a sodium salt, a potassium salt, and a lithium salt, an alkaline earth metal salt such as a calcium salt, a magnesium salt (hereinafter, the salt is not particularly noted. Means an alkali metal salt or an alkaline earth metal salt).

The synthetic water-soluble polymer (b3) is classified into addition polymerization type water-soluble polymer (b31), condensation polymerization type water-soluble polymer (b32) and the like. The addition-polymerization type water-soluble polymer (b31) also includes a water-soluble polymer by subjecting it to hydrolysis treatment after polymerization. The hydrolysis treatment can be performed by a known method. As the addition-polymerization type water-soluble polymer (b31), a polymer compound obtained by radical polymerization, anion polymerization or cationic polymerization of one or more kinds of monomers, or these polymer compounds are chemically treated again. The polymer compound obtained by the above can be used. Examples of the chemical treatment include treatments such as oxidation, esterification, etherification and cross-linking, and in any case, a known method can be used. The monomer is a main constituent monomer (m1) that can be a water-soluble polymer after homopolymerization of the monomer or by performing a hydrolysis treatment after the homopolymerization as needed, and after homopolymerization, It can be classified as a copolymerizable monomer (m2) that cannot become a water-soluble polymer.

As the main constituent monomer (m1), known ones can be used, for example, alkylene (having 2 carbon atoms).
~ 3) Oxide (m11), carboxyl group (-CO
₂ H) -containing vinyl monomer (m12), sulfo group (-S
O ₃ H) -containing vinyl monomer (m13), hydroxyl group (-O
H) -containing vinyl monomer (m14), vinyl monomer (m15) that becomes water-soluble by hydrolysis, and other vinyl monomer (m16) can be used.

Examples of the alkylene (C2-3) oxide (m11) include ethylene oxide and propylene oxide. As the carboxyl group-containing vinyl monomer (m12), a carboxyl group-containing vinyl monomer having 2 to 6 carbon atoms can be used.
Examples thereof include acrylic acid, methacrylic acid, (anhydrous) maleic acid, fumaric acid, itaconic acid, and salts thereof. As the sulfo group-containing vinyl monomer (m13), a sulfo group-containing vinyl monomer having 2 to 10 carbon atoms can be used, and examples thereof include vinyl sulfonic acid, allyl sulfonic acid, styrene sulfonic acid, and 2-acrylamido-2-methylpropane. Examples thereof include sulfonic acid, 2-hydroxy-3-butene sulfonic acid and salts thereof.

As the hydroxyl group-containing vinyl monomer (m14), there can be used a hydroxyl group-containing vinyl monomer having 3 to 30 carbon atoms, such as α-hydroxyacrylic acid,
Hydroxyethyl acrylate, hydroxypropyl acrylate, hydroxyethyl methacrylate, hydroxypropyl methacrylate, ethylene oxide 10 mol adduct of acrylic acid, ethylene oxide 5 mol propylene oxide 3 mol block adduct of acrylic acid, vinyl alcohol and these Salt etc. are mentioned. As the vinyl monomer (m15) which becomes water-soluble by hydrolysis,
In addition to acrylonitrile and methacrylonitrile, vinyl monomers having an ester bond having 4 to 10 carbon atoms can be used, and examples thereof include methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, butyl acrylate, and methacrylic acid. Hexyl, glycidyl methacrylate, vinyl acetate and the like can be mentioned. As the other vinyl monomer (m16), an amide monomer having 3 to 10 carbon atoms and an amine monomer having 7 to 10 carbon atoms can be used, and examples thereof include acrylamide, methacrylamide, diacetone acrylamide, t-butyl acrylamide, N-. Examples thereof include methylol acrylamide, diacetone acrylamide, dimethylaminoethyl acrylate and dimethylaminopropyl methacrylate.

Of the main constituent monomers (m1), alkylene oxide (m11), carboxyl group-containing vinyl monomer (m12) and hydroxyl group-containing vinyl monomer (m14).
And vinyl monomers that become water-soluble by hydrolysis (m1
5) is preferable, and more preferably, alkylene oxide (m11) and carboxyl group-containing vinyl monomer (m
12) and a vinyl monomer (m15) which becomes water-soluble by hydrolysis, particularly preferably ethylene oxide, vinyl acetate, acrylic acid, (anhydrous) maleic acid, fumaric acid,
Itaconic acid and salts thereof, most preferably ethylene oxide and vinyl acetate.

As the copolymerizable monomer (m2), known ones can be used, for example, alkylene (C4-8) oxide (m21), alkene and alkyne (m22), diene (m23). And aromatic alkenes (m
24) etc. can be used. Examples of the alkylene (C4-8) oxide (m21) include butylene oxide, tetrahydrofuran and styrene oxide. As the alkene and alkyne (m22), an aliphatic unsaturated hydrocarbon having 2 to 4 carbon atoms can be used, and for example,
Examples thereof include ethylene, propylene, 1-butene, 2-butene, isobutylene, cyclopentene and acetylene. As the diene (m23), a diene having 4 to 10 carbon atoms can be used, and examples thereof include butadiene and cyclopentadiene. As the aromatic alkene (m24), an aromatic unsaturated hydrocarbon having 6 to 10 carbon atoms can be used, and examples thereof include styrene and vinyltoluene.

Among the copolymerizable monomers (m2), alkylene oxide (m21) and alkene and alkyne (m22) are preferable, alkene and alkyne (m22) are more preferable, and ethylene and propylene are particularly preferable.

As the addition polymerization type water-soluble polymer (b31) obtained by using these monomers, for example, polyethylene glycol, polyethylene glycol acetic acid monoester, ethylene oxide-propylene oxide copolymer (molar ratio = 8: 2), polyvinyl alcohol (hydrolysis rate: 98%), polycondensation product of polyvinyl alcohol (hydrolysis rate: 98%) and formalin, polyvinyl alcohol (hydrolysis rate: 75%), polyacrylonitrile (number average molecular weight 5, 000), polyacrylic acid and acrylamide-acrylic acid copolymer (molar ratio = 3: 1)
Etc.

As the condensation polymerization type water-soluble polymer (b32), a carboxylic acid (anhydride) (m3) and a hydroxyl group- and / or amino group-containing compound (m4) are esterified and / or
Alternatively, a polymer obtained by a polycondensation reaction such as amidation can be used. As the carboxylic acid (anhydride) (m3), known ones can be used, for example, monovalent carboxylic acid (m31) and polyvalent carboxylic acid (anhydride) (m32).
Etc. can be used. As the monovalent carboxylic acid (m31),
A monovalent carboxylic acid having 1 to 20 carbon atoms or more can be used, and for example, formic acid, acetic acid, propionic acid, myristic acid, stearic acid, linoleic acid, linolenic acid, oleic acid, glycolic acid, lactic acid and tartaric acid can be used. Can be mentioned.

As the polyvalent carboxylic acid (anhydride) (m32), a polyvalent (2 to 4 or more) carboxylic acid having 1 to 20 or more carbon atoms can be used. For example, (anhydrous)
Phthalic acid, isophthalic acid, terephthalic acid, succinic acid (anhydrous), adipic acid, azelaic acid, sebacic acid, tetrahydro (anhydrous) phthalic acid, hexahydro (anhydrous) phthalic acid, (anhydrous) maleic acid, fumaric acid, itaconic acid, Examples thereof include (anhydrous) trimellitic acid and (anhydrous) pyromellitic acid.

Among the carboxylic acids (anhydrides) (m3), polyvalent carboxylic acids (m32) are preferable, and more preferably (succinic anhydride), adipic acid, azelaic acid, sebacic acid, maleic acid (anhydrous), and fumaric acid. Acid and itaconic acid,
Particularly preferred are (anhydrous) succinic acid, adipic acid, fumaric acid and itaconic acid.

Compound containing hydroxyl group and / or amino group (m
As 4), known ones can be used, for example, monohydric alcohol (m41), polyhydric alcohol (m42), monohydric amine (m43), polyhydric amine (m44), alkylene oxide adduct of alcohol (m45). ), An alkylene oxide adduct of an amine (m46), an alkylene oxide adduct of a carboxylic acid (m47), and the like can be used. The monohydric alcohol (m41) has 1 to 2 carbon atoms.
Zero or more monohydric alcohols and the like are used, for example, 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), polyhydric alcohol having 1 to 30 or more carbon atoms (2 to 4 or more)
Alcohol or the like is used, for example, ethylene glycol, propylene glycol, 1,3-butylene glycol, 1,6-hexanediol, diethylene glycol, dipropylene glycol, neopentyl glycol, triethylene glycol, glycerin, diglycerin, tetraglycerin, Examples thereof include trimellilol propane, sorbitol, pentaerythritol, dipentaerythritol and tripentaerythritol.

The monovalent amine (m43) has 1 carbon atom.
~ 50 or more monovalent amines and the like are used, for example, methylamine, ethylamine, hexylamine, ethanolamine, stearylamine, laurylamine,
Examples thereof include triethylamine, diethanolamine, triethanolamine and dicyclohexylamine.
As the polyvalent amine (m44), a polyvalent (2-4 or more) amine having 1 to 50 carbon atoms or more is used, and examples thereof include ethylenediamine, diethylenetriamine, triethylenetetramine, urea and melamine. To be

The alkylene oxide adduct of alcohol (m45) is an alkylene (having 2 to 4 carbon atoms) of monohydric alcohol (m41) or polyhydric alcohol (m42).
Oxide adducts (addition number 1 to 30 or more) and the like are used, for example, methanol ethylene oxide 1
Examples thereof include 0 adduct, pentaerythritol ethylene oxide 20 adduct, butanol ethylene oxide 20 propylene oxide 10 block adduct, and the like.

Alkylene oxide adduct of amine (m
As 46), an alkylene (C2-4) oxide adduct (addition number 1-30 or more) of a monovalent amine (m43) or a polyvalent amine (m44) is used,
For example, an adduct of 12 methylamine ethylene oxide, an adduct of 12 ethylene oxide and 4 propylene oxide blocks of ethylenediamine, and the like can be mentioned.

As the alkylene oxide adduct (m47) of carboxylic acid, alkylene (having 2 to 4 carbon atoms) of monovalent carboxylic acid (m31) or polyvalent carboxylic acid (m32).
Oxide adducts (addition number 1 to 30 or more) and the like are used, and examples thereof include an adduct of ethylene oxide with 12 acetates and an adduct of ethylene oxide with oleic acid of 30.

Compound containing hydroxyl group and / or amino group (m
Among 4), polyhydric alcohol (m42), alkylene oxide adduct of alcohol (m45) and alkylene oxide adduct of carboxylic acid (m47) are preferable,
More preferred are polyhydric alcohols (m42), alcohol alkylene oxide adducts (m45), particularly preferably sorbitol and alcohol alkylene oxide adducts (m45), most preferably alcohol alkylene oxide adducts (m45).

Examples of the condensation polymerization type water-soluble polymer (b32) obtained by using these (m3) and (m4) include, for example, acetic acid monoester of pentaerythritol ethylene oxide 20 mol adduct, sorbitol stearic acid monoester. Ester, glycerin ethylene oxide 10
Polyester (Mn1) composed of a molar adduct and succinic acid
500), polyester (Mn3000) composed of sorbitol and maleic acid, polyester (Mn8000) composed of adipic acid and polyethylene glycol, and the like.

Among the water-soluble resins (B), the semi-synthetic water-soluble polymer (b2) and the synthetic water-soluble polymer (b3) are preferable, and the synthetic water-soluble polymer (b3) is more preferable. Among the synthetic water-soluble polymers (b3), nonionic water-soluble polymers are preferable, and polyoxyalkylene group-containing compounds are more preferable. Here, the nonionic water-soluble polymer means, in the molecule, one or more ionic groups (for example, a carboxylate group (—COO ⁻ group), a sulfonate group (—SO ₃ ^— group), an ammonio group ( -N ⁺ H ₃ )
And it means a water-soluble polymer containing no trialkylammonio group (-N ⁺ R ₃₎ and the like}. In addition, R is carbon number 1
4 represents a hydrocarbon group of 4 (such as methyl, ethyl and isobutyl). Further, the polyoxyalkylene group-containing compound,
It means a compound having a polyoxyalkylene (having 2 to 4 or more carbon atoms), a skeleton (for example, a polyoxyethylene skeleton, a polyoxypropylene skeleton, a polyoxybutylene skeleton, or a mixed skeleton thereof) in a molecule. To do. When these water-soluble resins (B) are used, dryness and leak resistance are more likely to be improved under normal pressure when a conventional absorbent is applied to an ultrathin absorbent article.

The water-soluble resin (B) is preferably solid, more preferably particulate, from the viewpoint of handleability and the like. In the case of particles, the shape is not particularly limited, and may be any shape such as spherical, granular, crushed, needle-shaped, flaky, or agglomerated such that primary particles of these are fused together.

The water-soluble resin (B) can also be used in the form of being dissolved or emulsified in water and / or a volatile solvent.
As a volatile solvent, vapor pressure at 20 ° C is 17.5 mm
It is preferably Hg or more, more preferably 20 mm.
Hg or more, particularly preferably 30 mmHg or more, 700 mmHg or less, more preferably 600 mmHg or less, particularly preferably 50 mmHg or less.
It is 0 mmHg or less. Examples of such a volatile solvent include alcohols (methanol, ethanol, isopropyl alcohol, etc.), hydrocarbons (hexane, cyclohexane, toluene, etc.), ethers (diethyl ether, tetrahydrofuran, etc.), ketones (acetone, methyl ethyl ketone, etc.), Examples thereof include esters (ethyl acetate, isopropyl acetate, diethyl carbonate, etc.). When using water and a volatile solvent, the amount of water used is 1% by weight based on the total weight of the water and the volatile solvent.
The above is preferable, more preferably 5% by weight or more, particularly preferably 10% by weight or more, and 99% by weight or less, further preferably 95% by weight or less, particularly preferably 90% by weight or less. When water and / or a volatile solvent is used, the amount thereof is preferably 1% by weight or more, more preferably 2% by weight or more, particularly preferably 3% by weight, based on the weight of the water-soluble resin (B). %
It is above, and preferably 900% by weight or less, more preferably 700% by weight or less, and particularly preferably 400.
It is less than or equal to wt.

The content of the water-soluble resin (B) is preferably 0.05% by weight or more, more preferably 0.1% by weight or more, particularly preferably 1. based on the weight of the water-absorbent resin (A). 0% by weight or more, more preferably 1.5% by weight
Or more, most preferably 2.0% by weight or more, and
It is preferably 20.0% by weight or less, more preferably 1
It is 8.5% by weight or less, particularly preferably 17.0% by weight or less, more preferably 14.5% by weight or less, and most preferably 12.0% by weight or less. When the content is in this range, when the absorbent of the present invention is applied to an ultrathin absorbent article, the dryness and the leak resistance are more likely to be improved under normal pressure. It should be noted that the water-absorbent resin (A) is cross-linked with a low-molecular weight water-soluble oligomer (for example, the water-absorbent resin (A)) derived from a raw material of the water-absorbent resin (A) produced during the production of the water-absorbent resin (A). Polyacrylic acid (salt) (a
In the case of 2), as the low molecular weight water-soluble oligomer, a low molecular weight water-soluble crosslinked polyacrylic acid (salt) is produced).
However, the water-soluble oligomer component is not contained in the water-soluble resin (B). The content of the water-soluble resin (B) can be quantified by the following extraction method in addition to being calculated from the amounts of the absorbent resin (A) and the water-soluble resin (B) used.

<Extraction method> 1000 ml of deionized water is added to a 3000 ml beaker, and 20.0 g of a measurement sample is added thereto. Extraction is performed at 25 ° C. for 5 hours while stirring with a 5.0 cm long stirrer (so-called stirrer chip) and a magnetic stirrer at 600 rpm. Then Whatman
Filter with GF / F filter paper to obtain the filtrate as an extract.
The extract is evaporated to dryness (120 ° C x 3 hours), and the weight of the evaporation residue is measured. If necessary, further high performance liquid chromatography and nuclear magnetic resonance spectrum (NMR)
The content concentration of the water-soluble resin (B) contained in the above evaporation residue may be determined by instrumental analysis such as.

The absorbent of the present invention can be produced, for example, by adding and mixing the water-soluble resin (B) with the water-absorbent resin (A). As the step of mixing and treating the water-soluble resin (B) with the water-absorbent resin (A), in the case of aqueous solution polymerization, immediately before the polymerization step, immediately after the polymerization step, and immediately before the dehydration step (water content 1
Dehydration step to about 0% by weight), during the dehydration step, immediately after the dehydration step, immediately before the pulverization step, during the pulverization step, immediately before the surface crosslinking treatment step, during the surface crosslinking treatment step, immediately after the surface crosslinking treatment, and the drying step (water content 10 Immediately before the step of drying to below wt%),
Examples thereof include during the drying step and after the drying step. Of these, immediately before the polymerization step, 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 drying. After the step is preferable, more preferably immediately before the polymerization step, immediately before the dehydration step, immediately before the pulverizing 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 polymerization step, immediately before the dehydration 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, and particularly preferably, immediately before the polymerization step, immediately before the dehydration step, immediately before the surface crosslinking treatment step and immediately before the drying step, and most preferably Preferably, it is immediately before the surface crosslinking treatment step and immediately before the drying step.

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 dehydration up to a water content of about 10% by weight), immediately after the dehydration step, during the step of separating the water-absorbent resin obtained by the polymerization from the organic solvent used for the polymerization, surface cross-linking treatment Immediately before the step, during the surface crosslinking treatment step, immediately after the surface crosslinking treatment step, immediately before the drying step (step of drying to a water content of 10% by weight or less), during the drying step, after the drying step, and the like. Of 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 the 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 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 the 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, and dried. Immediately before the process and during the drying process.

As for the water content, 2.000 g of a measurement sample is measured by an infrared heating moisture meter (for example, trade name: FD-100).
Mold, manufactured by Kett) and allowed to stand at 125 ° C. for 20 minutes, and then the weight (h) is measured and calculated from the following formula.

[Equation 1]

The industrial apparatus for mixing and treating the water-absorbent resin (A) and the water-soluble resin (B) is not particularly limited, but for example, a conical blender, an internal mixer (Banbury mixer), a self-cleaning apparatus. Type mixer, gear compounder, screw type extruder,
Screw type kneader, mincing machine, nauter mixer,
Mechanical mixing devices such as a double-arm kneader, a V-type mixer, a fluidized bed type mixer, a turbulator, a screw type line blending device, a ribbon mixer and a mortar mixer are preferably used. These can also be used in combination.

As a method of mixing and treating with these mixing devices, a method of adding or spraying the water-soluble resin (B) while stirring the water-absorbent resin (A) in the above-mentioned mixing device and mixing and treating it beforehand, A high concentration of (B) is added to and mixed with (A) to prepare a masterbatch, and as (B), the masterbatch is added to (A) and mixed and treated so that a predetermined addition amount is obtained. Methods and the like.

The water absorption capacity (KB) of the absorbent of the present invention is 3
It is preferably 0 g / g or more, more preferably 40 g / g
Or more, particularly preferably 45 g / g or more, most preferably 50 g / g or more, and preferably 85 g / g or less, more preferably 80 g / g or less, particularly preferably 70 g / g or less, most preferably 65 g / g. g or less. When the water absorption capacity (KB) is in this range, the dryness and the leak resistance are more likely to be further improved under normal pressure when the absorbent of the present invention is applied to the absorbent article.

<Measurement Method of Water Absorption Capacity (KB)> Opening 63
In a tea bag (rectangular bag of 20 cm in length and 10 cm in width) made of a nylon net of μm (JIS Z8801-2000), a JIS standard sieve (JIS Z8801-
2000), 1.000 g of a measurement sample adjusted to a particle size of 850 to 150 μm is weighed and put in 500 ml of physiological saline (0.9 wt% sodium chloride aqueous solution) for 60 minutes. Then, the tea bag is taken out from the physiological saline and hung for 15 minutes, the weight (a) is measured, and the water absorption capacity is calculated from the following equation.

[Equation 2] However, b is a blank weight obtained by performing the same operation using only the nylon mesh bag. In addition, weigh up to four decimal places and round off the fourth digit.

The water retention capacity (HS) of the absorbent of the present invention is 20.
It is preferably g / g or more, more preferably 23 g / g or more, particularly preferably 26 g / g or more, more preferably 29 g / g or more, most preferably 32 g / g or more, and preferably 70 g / g or less. , More preferably 60 g / g or less, particularly preferably 55 g / g or less, more preferably 50 g / g or less, most preferably 48 g / g or less.
It is g / g or less. When the water retention amount (HS) is in this range, the dryness and the leak resistance are more likely to be improved under normal pressure when the absorbent of the present invention is applied to the absorbent article.

<Measurement Method of Water Retention (HS)> Opening 63μ
1.000 g of the measurement sample put in a nylon mesh bag (10 x 20 cm) of m was immersed in 1 liter of physiological saline for 60 minutes, and then centrifugally dehydrated at 150 G for 90 seconds. c) is measured and the water retention amount is calculated from the following formula.

[Equation 3] However, d is a blank weight obtained by performing the same operation using only the nylon mesh bag. In addition, weigh up to four decimal places and round off the fourth digit.

Absorption under load (KK) of the absorbent of the present invention
Is 6 g / g or more, preferably 8 g / g or more, more preferably 10 g / g or more, particularly preferably 12 g.
/ G or more, most preferably 14 g / g or more, and 40 g / g or less, preferably 37 g / g or less, more preferably 34 g / g or less, particularly preferably 31 g / g or less, most preferably 28 g / G or less. When the absorbed amount under load is within this range, the dryness and the leakage resistance under load are likely to be further improved when the absorbent of the present invention is applied to an absorbent article.

<Measurement Method of Absorption Under Load (KK)> A mesh having an opening of 63 μm on one side of the opening (JIS Z8801-2).
000) mounted cylindrical tube (inner diameter 25.4 mm, length 3
5mm) stands vertically, and the measurement sample (opening 250
0.1500 g (particle size portion of 500 μm) so as to have a uniform thickness, an acrylic plate (diameter 25 mm, thickness 8 mm) and a weight of 200 g are placed on the measurement sample, and then all of these weights are weighed. (E) is measured. Then
A portion of the above-mentioned cylindrical tube (mesh portion of 63 μm) in 25 g of physiological saline in a horizontally placed petri dish (85 mm in diameter)
Dip for 60 minutes, pull up and weigh the entire cylindrical tube (f)
Then, the absorption amount under load (KK) is calculated from the following formula.

[Equation 4]

Additives may be added to the absorbent of the present invention. As the additives, for example, antiseptics, fungicides, antibacterial agents, antioxidants, ultraviolet absorbers, coloring agents, aromatic agents, deodorants, inorganic powders and fibrous substances are used.
Examples of preservatives include preservatives such as salicylic acid, sorbic acid, dehydroacetic acid and methylnaphthoquinone, and bactericidal agents such as chloramine B and nitrofurazone. Examples of the fungicide include butyl p-oxybenzoate and the like. Examples of the antibacterial agent include benzalkonium chloride and chlorhexidine gluconate.

Examples of the antioxidant include hindered phenol antioxidants {triethylene glycol-bis- [3- (3-t-butyl-5-methyl-4-hydroxyphenyl) propionate], 1,6- Hexanediol-bis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate], octadecyl-3
-(3,5-di-t-butyl-4-hydroxyphenylpropionate and 3,5-di-t-butyl-4-hydroxybenzylphosphonate-diethyl ester, etc.}, amine antioxidant {n- Butylamine, triethylamine, diethylaminomethyl methacrylate, etc.}
And mixtures of two or more of these.

Examples of the ultraviolet absorber include benzotriazole ultraviolet absorbers {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 UV absorber {2
-(4,6-Diphenyl-1,3,5-triazine-2
-Yl) -5-[(hexyl) oxy] -phenol etc., benzophenone ultraviolet absorber {2-hydroxy-
4-n-octyloxybenzophenone, etc., an oxalic acid anilide ultraviolet absorber {2-ethoxy-2′-ethyloxalic acid bisanilide, etc.}, and a mixture of two or more thereof.

Examples of colorants include inorganic pigments such as carbon black, titanium oxide, red iron oxide, red lead, rose red, dark blue and ferrite, organic pigments such as azo lake, benzimidazolone and phthalocyanine, and nigrosine and aniline. And the like. Examples of the fragrance include natural flavors such as musk, Avies oil and turpentine, and synthetic flavors such as menthol, citral, p-methylacetophenone and floral. Examples of the deodorant include activated carbon, zeolite, silica, flavonoid, cyclodextrin and the like.

Examples of the inorganic powder include calcium carbonate, kaolin, talc, mica, bentonite, clay, sericite, asbestos, carbon black, glass (powder, fiber and balloon), shirasu, graphite, metal (iron, copper, Aluminum and gold), ceramics (alumina, barium titanate, silicon carbide, carbon nitride, etc.), silica, zeolite, asbestos, and the like. The inorganic powder may have any form, and the weight average particle diameter is preferably 0.1 μm to 1 mm.

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

When additives are used, the contents of the additives are not particularly limited, but the contents of antiseptics, fungicides, antibacterial agents, antioxidants, ultraviolet absorbers, aromatics and deodorants are not limited. , Respectively, based on the weight of the water-absorbent resin (A), 0.00
001 wt% or more is preferable, and 0.0 is more preferable.
It is 0005 wt% or more, preferably 10 wt% or less, and more preferably 5 wt% or less. Also,
The content of the colorant, the inorganic powder and the fibrous substance is 0.1% by weight based on the weight of the water absorbent resin (A).
The above is preferable, more preferably 0.2% by weight or more, and 25% by weight or less is preferable, and further preferably 15% by weight or less.

The absorbent of the present invention is suitable as a material for forming an ultrathin absorbent article. As an ultra-thin absorbent article, hygiene articles are typical, for example, paper diapers (children's paper diapers and adult paper diapers, etc.), napkins (sanitary napkins, etc.), paper towels, pads (pads for incontinence and Examples include surgical underpads), pet sheets (pet urine absorption sheet, heat retaining sheet, etc.), and the like.
In addition to hygiene products, various household and industrial absorbent sheets (eg, freshness-retaining sheets, drip absorbent sheets, paddy rice nursery sheets, concrete curing sheets, water-running prevention sheets such as cables, etc.) can be mentioned. . Of these, the absorbent of the present invention is particularly suitable for ultrathin disposable diapers, pads and sanitary napkins. Therefore, these ultra-thin absorbent articles can be used for the purpose of reducing discomfort and discomfort during use.

The absorbent article comprises an absorbent body containing an absorbent as an essential component. As the method for obtaining this absorbent, a method of simultaneously mixing and laminating the absorbent of the present invention and the fibrous material in an air stream, and mixing the absorbent of the present invention and the fibrous material in advance in an air stream A method of stacking fibers, and stacking the absorbent of the present invention on the fibrous material,
Further, a method of stacking fibrous materials can be mentioned. Among these methods, the method of and is preferable, and the method of is more preferable. There are no particular restrictions on the devices used in these methods, and ordinary devices can be used,
For example, a drum forming device may be used.

The basis weight of the absorbent of the present invention contained in the absorber {content of the water-absorbent resin per unit area of the absorber layer}
Is preferably 10 g / m ² or more, more preferably 2
0 g / m ² or more, particularly preferably 30 g / m ² or more, most preferably 40 g / m ² or more, and 1000 g
/ M ² or less is preferable, more preferably 900 g / m ²
The amount is particularly preferably 800 g / m ² or less, and most preferably 700 g / m ² or less. When the absorbent body of the present invention is applied to hygiene products, the basis weight of the absorbent of the present invention is preferably 10 g / m ² or more, and more preferably 2
0 g / m ² or more, particularly preferably 30 g / m ² or more, most preferably 40 g / m ² or more, and 400 g / m ²
It is preferably m ² or less, more preferably 300 g / m ² or less, particularly preferably 250 g / m ² or less, and most preferably 200 g / m ² or less. When the basis weight is in this range, the water retention capacity of the absorbent body becomes higher, and when applied to an absorbent article, it tends to exhibit more excellent dryness and leak resistance under normal pressure.

The basis weight of the fibrous material contained in the absorber is 1
It is preferably 0 g / m ² or more, more preferably 20 g / m ^2.
m ² or more, particularly preferably 30 g / m ² or more, most preferably 40 g / m ² or more, and preferably 1000 g / m ² or less, more preferably 900 g / m ² or less,
Particularly preferably 800 g / m ² or less, most preferably 7
It is not more than 00 g / m ² . When the absorbent body of the present invention is applied to hygiene products, the basis weight of the absorbent of the present invention is 10
g / m ² or more is preferable, more preferably 20 g / m ²
Or more, particularly preferably 30 g / m ² or more, most preferably 40 g / m ² or more, and preferably 400 g / m ² or less, more preferably 300 g / m ² or less, particularly preferably 250 g / m ² or less, Most preferably 200
g / m ² or less. When the weight per unit area is within this range, when applied as an absorbent article, it tends to exhibit more excellent dryness and leak resistance under normal pressure.

The content of the absorbent of the present invention is preferably 40.0% by weight or more, more preferably 42.0% by weight or more, even more preferably, based on the total weight of the absorbent and the fibrous material. 44.0% by weight or more, particularly preferably 4
6.0 wt% or more, more preferably 48.0 wt%
As described above, preferably 50.0% by weight or more, next more preferably 52.5% by weight or more, next more preferably 55.0% by weight or more, then particularly preferably 57.5% by weight or more, And particularly preferably 60.
0% by weight or more, most preferably 62.0% by weight or more, and preferably 99.9% by weight or less, more preferably 99.5% by weight or less, even more preferably 9% by weight or less.
9.0% by weight or less, particularly preferably 97.5% by weight or less, more preferably 95.0% by weight or less, next preferably 92.5% by weight or less, and further preferably 90.0% by weight or less. And more preferably 8
It is 7.5% by weight or less, particularly preferably 85.0% by weight or less, more preferably 82.5% by weight or less, most preferably 80.0% by weight or less. When the content of the absorbent is within this range, the absorbent article can be made thinner, and further, it tends to exhibit excellent dryness and leak resistance under normal pressure.

The thickness of the absorber is preferably 0.5 mm or more, more preferably 1.0 mm or more, even more preferably 1.5 mm or more, particularly preferably 2.0 mm or more, and particularly preferably 2.5 mm or more. Yes, again
It is preferably 5.0 mm or less, more preferably 4.5 m
m or less, more preferably 4.0 mm or less, particularly preferably 3.5 mm or less, and particularly preferably 3.0 m.
m or less. When the thickness of the absorbent body is within this range, the absorbent article can be made thinner, and the discomfort and discomfort during use of the absorbent article can be further reduced.

The SDME surface dryness (DS) of the absorbent article containing the absorbent containing the absorbent of the present invention as an essential constituent is preferably 40% or more, more preferably 45% or more, and particularly preferably 50. % Or more, most preferably 52% or more, preferably 100% or less, more preferably 99% or less, particularly preferably 98%.
% Or less, and most preferably 95% or less. When the SDME surface dryness is within this range, the dryness of the absorbent article tends to be further improved.

<Method of measuring SDME surface dryness (DS)> An inner diameter of 6.
One end of the opening of a cylindrical cylinder having a height of 0 cm and a height of 3.8 cm is placed in contact with the measurement sample, and 160 ml of physiological saline (0.9 wt% sodium chloride aqueous solution) is poured into the cylindrical cylinder. Immediately after removing the cylindrical cylinder, immediately irradiate the surface layer part of the measurement sample with visible light from the 45 ° direction to the central part of the measurement sample, and measure the intensity of the light reflected from the surface layer part of the measurement sample in the 90 ° direction. It is calculated by measuring the light intensity (Is) 7 minutes after the removal of the cylindrical cylinder (7-minute value).

The calculation method was as follows: The intensity of light (I ₁₀₀ ) measured without pouring physiological saline into the measurement sample (water content is less than 5.5% by weight) was dryness 10
The light intensity (I ₀ ) measured after being immersed in 5000 ml of physiological saline for 30 minutes was set to 0%, and the dryness was set to 0%, and these values and the light intensity (Is) were proportionally calculated. All measurements are 25 ± 3 ℃, 60 ± 5RH%
Under the atmosphere. Further, as an SDME surface dryness measuring device capable of irradiating the central portion of the measurement sample with visible light from the 45-degree direction of the measurement sample and measuring the intensity of light reflected in the 90-degree direction from the surface layer of the measurement sample, for example, The apparatus described in European Patent No. 0312919 or US Pat. No. 49,924,084 can be used.

Leakage resistance (TM) of an absorbent article containing an absorber containing the absorbent of the present invention as an essential component
Is preferably 200 g or more, more preferably 220
g or more, particularly preferably 240 g or more, most preferably 250 g or more, and preferably 1200 g or less, more preferably 1000 g or less, particularly preferably 900 g or less, most preferably 800 g or less. When the moisture resistance (TM) is in this range, the dryness and the moisture resistance of the absorbent article under normal pressure tend to be further improved.

<Molecular resistance measuring method (TM)> The central portion of the measurement sample was cut into a size of 10 × 30 cm, and flattened on a plate inclined at 45 °, with one end of 10 cm on top.
Lay 10 cm with the other end down (nothing applied to the ends of the cut absorbent article). 3 cm from one end of the upper part of this measurement sample (that is, 27 cm from the other end of the lower part), 10c
A physiological saline solution (0.9 wt% sodium chloride aqueous solution) is injected into a 5 cm portion (range of about 3 cm ² ) from either end of m at a rate of 400 g / min using a glass tube with an inner diameter of 1 cm. . The liquid is injected from a position about 1 cm away from the surface of the absorbent article, and is naturally dropped without applying pressure or the like. The time (i) (seconds) from the start of the injection of the physiological saline to the start of the leakage of the physiological saline from the other end of the lower portion of the measurement sample is measured, and the absorption amount to the leakage is calculated from the following equation. The measurement is performed three times, and the average value thereof is obtained to obtain the leak resistance (TM). All measurements are performed in an atmosphere of 25 ± 3 ° C. and 60 ± 5 RH%.

[Equation 5]

As the structure of an ultra-thin sanitary article, for example, a liquid-permeable top sheet (OS) is arranged on the uppermost layer, a liquid-impermeable backsheet (US) is arranged on the lowermost layer, and an intermediate layer between them. As an absorbent body composed of an absorbent and a fibrous material (1
(K1) having a structure (K1) in which a liquid permeable surface sheet (OS) is arranged as the uppermost layer and a liquid impermeable back sheet (US) is arranged as the lowermost layer, and (K1) is used as an intermediate layer thereof. A structure in which 2 to 4 layers of the same absorber are stacked to arrange a laminated absorber, and one or more kinds of liquid-permeable intermediate sheets (CS) are provided between the absorbers of the laminated absorber as required. In the (K2) and (K1) or (K2) structure, at least one liquid-permeable intermediate sheet (CS) is arranged between the uppermost layer and the intermediate layer and / or between the intermediate layer and the lowermost layer. Structure (K3)
(In this case, the diffusibility of water, urine, feces, menstrual blood and the like absorbed by the absorbent article can be easily improved.) And the like. Of these, (K3) is preferable from the viewpoint of leakage of the absorbent from hygiene products.

As a concrete example of the ultra-thin sanitary article, a paper diaper will be described. A liquid-permeable top sheet (OS) is arranged on the surface of the sanitary article, and a liquid-impermeable back sheet (US) is provided on the back surface. ) Is arranged, and a liquid-permeable intermediate sheet (CS) is further stacked on the upper and lower parts of the absorber layer as necessary,
Furthermore, it is equipped with gathers and tapes for attachment to the human body, and it is possible to finish it into a paper diaper.

As the liquid permeable surface sheet (OS) used for an ultra-thin sanitary article, it is possible to easily absorb water, seawater, muddy water, urine, feces, menses, etc., which are absorbed by the absorbent article. It is not particularly limited as long as it penetrates the thickness and is absorbed by the absorber layer, for example, paper (Japanese paper and tissue paper etc.) made of cellulose fiber, non-woven fabric, woven fabric or knitted fabric made of thermoplastic resin or the like. A perforated film made of cloth, a thermoplastic resin or the like is preferably used. The hole diameter of the perforated film is preferably 0.01 mm or more, more preferably 0.02 mm or more, particularly preferably 0.03 mm or more, and 300 m.
m or less, more preferably 200 mm or less,
It is particularly preferably 100 mm or less.

Examples of the thermoplastic resin include polyolefins (polyethylene, polypropylene and polyethylene / polypropylene copolymers), polyesters (polyethylene terephthalate and polyethylene terephthalate / polyethylene isophthalate copolymers), polyolefin / polyester copolymers ( Polyethylene / polyethylene terephthalate copolymer and polypropylene
Polyethylene terephthalate copolymer etc.), polyamide (polyterephthalic acid ethylenediamide, polyisoterephthalic acid ethylenediamide, polyterephthalic acid propylenediamide and polyisoterephthalic acid propylenediamide fiber etc.), polyacryl (polyacrylate butyl fiber and polyacryl) Acid 2-ethylhexyl fiber and the like) and polyacrylonitrile fiber and the like. Among these liquid permeable surface sheets (OS), a non-woven fabric, a woven fabric and a knitted fabric made of a thermoplastic resin are preferable, more preferably a non-woven fabric made of a thermoplastic resin, particularly preferably a polyolefin resin, a polyester resin or a polyolefin. -A non-woven fabric made from a polyester copolymer.

The thickness of the liquid-permeable surface sheet (OS) is not particularly limited, but it is preferably 5 μm or more, and more preferably from the viewpoint of the diffusibility of the substance to be absorbed and the thickness and flexibility of the absorbent article. Is 10 μm or more, particularly preferably 20 μm or more, most preferably 30 μm or more, and preferably 5000 μm or less, from the viewpoint of the diffusibility of the substance to be absorbed and the thickness and flexibility of the absorbent article,
More preferably 1000 μm or less, and particularly preferably 7
It is 50 μm or less, and most preferably 500 μm or less.

As the liquid impermeable back sheet (US) used for ultra-thin sanitary goods, water, seawater, muddy water, urine, feces, menses, etc. absorbed by the absorbent article are used as the back surface. There is no particular limitation as long as it can prevent exudation,
For example, a sheet made of the above-mentioned thermoplastic resin or the like is used. Of these, a sheet made of polyolefin is preferable, more preferably polyethylene,
A sheet made of polypropylene or polyethylene-polypropylene, particularly preferably a sheet made of polyethylene. The thickness of the back sheet is not particularly limited, but is preferably 5 μm or more, and more preferably 1 from the viewpoint of the thickness and flexibility of the absorbent article.
0 μm or more, particularly preferably 20 μm or more, most preferably 30 μm or more, and preferably 5000 μm or less, more preferably 1000 μm or less, particularly preferably 750 from the viewpoint of the thickness and flexibility of the absorbent article.
It is not more than μm, most preferably not more than 500 μm.

As the liquid-permeable intermediate sheet (CS) used as necessary, the same ones as those used for the liquid-permeable surface sheet (OS) can be used. Incidentally, the liquid-permeable intermediate sheet, the absorbent article, water, seawater, muddy water, urine,
This is for facilitating permeation of the substance to be absorbed such as feces and menstrual blood and being easily absorbed and diffused in the absorber layer. The materials and types of gathers and mounting tapes are not particularly limited, and known materials used for conventional absorbent articles can be used.

[0082]

EXAMPLES The usefulness of the present invention will be described below with reference to Examples and Comparative Examples, but the present invention is not limited thereto. Hereinafter, unless otherwise specified, parts means parts by weight,
% Means% by weight. Absorption under load (K
K), water absorption capacity (KB), and water retention capacity (HS) were measured by the same method as described above. <Example 1> 81.8 acrylic acid in a glass reaction container
Parts, N, N'-methylenebisacrylamide 0.3 parts and deionized water 241 parts were charged, and the temperature of the contents was kept at 1 to 2 ° C while stirring and mixing. Then, after nitrogen was flowed into the liquid layer of the contents for 30 minutes, 1 part of a 1% aqueous solution of hydrogen peroxide and 0.2% of an ascorbic acid aqueous solution were sealed.
Polymerization was initiated by adding and mixing 2 parts and 2.8 parts of a 2% 2,2′-azobisamidinopropane dihydrochloride aqueous solution (about 5 ° C.).

Although the temperature rises with the polymerization, the polymerization is continued at 70 to 80 ° C. for about 8 hours under sealed condition, and the polymer containing water is kneaded with an internal mixer to obtain a temperature of 45%. Aqueous sodium hydroxide solution 72.
Seven parts were added to neutralize 72 equivalent% of carboxyl groups. In addition, according to JIS K0113-1997 (0.
The degree of neutralization calculated from the acid value measured using a 1N aqueous potassium hydroxide solution as a titration solution was 70.1 equivalent%. Then, it is shredded to a size of 2 to 5 mm with an internal mixer, dried with an aeration band dryer under the conditions of 150 ° C. and a wind speed of 2.0 m / sec, and the dried product is crushed, followed by a standard sieve (JIS Z8801). -2000) to remove particles having a particle size of 710 μm or more and particles having a particle size of 150 μm or less to obtain particles having a particle diameter of 150 to 710 μm. 50 to 60 parts of this particle
While maintaining the temperature at 0 ° C., under high-speed stirring, ethylene glycol diglycidyl ether (Nagase Chemicals Co., Ltd., trade name: Denacol EX810) / water / methanol mixed solution (ethylene glycol diglycidyl ether / water / methanol [weight ratio] = 2 / 30/70) 3.5 parts, and continuously mixing for about 15 minutes while maintaining at 50 to 60 ° C.,
A water absorbent resin (A-1) was obtained by reacting at 140 ° C. for 40 minutes.

Further, (A-1), at 25 ° C. under high speed stirring with a mixer, 40% polyethylene glycol having a number average molecular weight of 4000 ((B-1), trade name: PEG-4
000S, Sanyo Chemical Industries, SP value: 9.4, water (2
Solubility in 5 ° C., 100 g): 2 g or more} Aqueous solution 1
5.0 parts was added and dried at 120 ° C. for 60 minutes to obtain the absorbent (1) of the present invention. Water absorption capacity of water absorbing agent (1) (K
B) is 58 g / g, and water retention capacity (HS) is 38 g / g,
The absorption amount under load (KK) was 15 g / g.

<Example 2> 40% number average molecular weight 400
0 of the amount of polyethylene glycol solution used is 20.0
An absorbent (2) was obtained in the same manner as in Example 1 except that the weight part was changed to 1.0 part by weight. The water absorbing agent (2) has a water absorption capacity (KB) of 57 g / g and a water retention capacity (HS) of 40 g / g.
The absorption amount under load (KK) was 16 g / g.

<Example 3> 40% number average molecular weight 400
0 of the amount of polyethylene glycol solution used is 20.0
An absorbent (3) was obtained in the same manner as in Example 1 except that the weight part was changed to 40.0 parts by weight. The water absorbing agent (3) has a water absorption capacity (KB) of 56 g / g and a water retention capacity (HS) of 36 g /
The absorption amount under load (KK) was 15 g / g.

Example 4 40% number average molecular weight 400
0 of the amount of polyethylene glycol solution used is 20.0
An absorbent (4) was obtained in the same manner as in Example 1 except that the weight part was changed to 6.0 parts by weight. The water absorbent (4) has a water absorption capacity (KB) of 58 g / g and a water retention capacity (HS) of 38 g /
The absorption amount under load (KK) was 16 g / g.

<Example 5> 40% number average molecular weight 400
From 20.0 parts by weight of a polyethylene glycol aqueous solution of 0, polyvinyl alcohol powder having a number average molecular weight of 25,000 {(B-2), trade name: Denka Poval K-05, manufactured by Denki Kagaku Kogyo Co., hydrolysis rate: 99%, SP Value: 19.
1, Solubility in water (25 ° C., 100 g): 2 g or more} An absorbent (5) was obtained in the same manner as in Example 1 except that the amount was changed to 3.0 parts by weight. Water absorption capacity (KB) of water absorbing agent (5)
Was 58 g / g, the water retention capacity (HS) was 39 g / g, and the absorption capacity under load (KK) was 16 g / g.

<Example 6> 40% number average molecular weight 400
0 from 20.0 parts by weight of polyethylene glycol aqueous solution, polyacrylic acid powder having a number average molecular weight of 5000 {(B
-3), trade name: polyacrylic acid 5,000, manufactured by Wako Pure Chemical Industries, SP value: 14.0, water (25 ° C, 100g)
Solubility: 2 g or more} Absorbent (6) was obtained in the same manner as in Example 1 except that the content was changed to 1.0 part by weight. The water absorbing agent (6) has a water absorption capacity (KB) of 57 g / g, a water retention capacity (HS) of 39 g / g, and an absorption capacity under load (KK) of 1
It was 6 g / g.

Example 7 208 parts of acrylic acid and water 1
To the mixed solution with 3.5 parts, 346.0 parts of 25% aqueous sodium hydroxide solution was added 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 Chemicals Co., Ltd., trade name: Denacol EX810) were added, The temperature was adjusted to 10 ° C. to prepare an aqueous monomer solution. Then, 624 parts of cyclohexane was placed in a four-necked round bottom flask equipped with a stirrer, a reflux condenser, a thermometer, and a nitrogen gas introduction tube, and polyoxyethylene octyl phenyl ether phosphate (trade name: PRYSURF A210G was added to this. (Manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) and dissolved therein, and then nitrogen gas was introduced while stirring at 400 rpm.

Then, it is heated to 75 ° C. and 400 rpm.
While stirring, the above monomer aqueous solution maintained at 5 to 10 ° C. was introduced from the liquid layer together with nitrogen gas at a substantially constant rate for 60 minutes. At this time, the oxygen concentration in the flask was 10
Keep at ~ 30 ppm. After completion of the introduction of the aqueous monomer solution, polymerization was further carried out at 75 ° C. for 30 minutes while stirring at 400 rpm, and then water was removed by azeotropic distillation with cyclohexane,
When stirring was stopped at the time when the water content of the produced polymer reached about 20% (the water content was a value calculated from the amount of removed water), the polymer particles settled, and thus the polymer particles were separated by decantation. Polymer particles were obtained by separating from cyclohexane. 40 parts of the obtained polymer particles (dry basis, 130 ° C.)
X 30 minutes dry value) and 140 parts of cyclohexane were placed in an eggplant flask, and glycerin polyglycidyl ether (Nagase Kasei Kogyo Co., Ltd., trade name: Denacol EX31) was placed in the flask.
4) After adding 3.4 parts of a 5% methanol solution, the mixture was heated at 60 ° C. and kept for 30 minutes, and further kept under reflux of methanol / cyclohexane for 30 minutes.

Then, filtration is performed to obtain polymer particles,
It was dried under reduced pressure at ℃ to obtain a water absorbent resin. Further, the water-absorbent resin thus obtained was stirred at 25 ° C. under high speed with a mixer to obtain 40
% Polyethylene glycol having a number average molecular weight of 6000 {(B-4), Sanyo Chemical Industry Co., Ltd., trade name PEG600
0, SP value: 14.0, solubility in water (25 ° C., 100 g): 2 g or more} 20.0 parts of an aqueous solution was added to give 12
It was dried at 0 ° C. for 60 minutes to obtain an absorbent (7). The water absorbing agent (7) has a water absorption capacity (KB) of 51 g / g, a water retention capacity (HS) of 32 g / g, and an absorption capacity under load (KK) of 2
It was 5 g / g.

<Comparative Example 1> After obtaining a water absorbent resin in the same manner as in Example 1, the absorbent (8) for comparison was used without mixing the water-soluble resin (B) used in the present invention. Obtained. The water absorbing agent (8) has a water absorption capacity (KB) of 56 g / g, a water retention capacity (HS) of 40 g / g, and an absorption capacity under load (KK) of 1
It was 5 g / g.

<Comparative Example 2> 40% number average molecular weight 400
20% polyethylene glycol aqueous solution of number average molecular weight 5000 {(B-5), Sanyo Chemical Industry Co., Ltd., trade name: Sun Wax 161-P, SP value:
8.5, solubility in water (25 ° C, 100g): 2g
Absorber (9) for comparison was obtained in the same manner as in Example 1 except that the aqueous solution of ethyl acetate was used. The water absorbent (9) has a water absorption capacity (KB) of 55 g / g and a water retention capacity (HS) of 3
The absorption amount under load (KK) was 4 g / g and 13 g / g.

Using the absorbents (1) to (7) of Examples 1 to 7 and the absorbents (8) to (9) of Comparative Examples 1 and 2, the following absorbents (1) to (15) were used. )made. <Production Example 1 of Absorbent Body> 12 parts of the absorbent (1) and 12 parts of Japanese Pharmacopoeia absorbent cotton (manufactured by Kawamoto Sangyo Co., Ltd.) were defibrated about 500 times by hand while being mixed until the appearance was uniform. Then, after disintegrating the defibrated mixture into a size of 15 cm × 45 cm, it is pressed with a heater plate press machine (model number N4008-00) manufactured by NPA System Co., Ltd. at 50 ° C. at 3 Kg / cm ² for 30 seconds. By doing so, an absorber (1) was obtained.

<Production Example 2 of Absorbent Body> An absorber (2) was obtained in the same manner as in Production Example 1 except that the absorbent (1) was changed to the absorbent (2).

<Production Example 3 of Absorbent Body> An absorber (3) was obtained in the same manner as in Production Example 1 except that the absorbent (1) was changed to the absorbent (3).

<Production Example 4 of Absorbent Body> An absorber (4) was obtained in the same manner as in Production Example 1 except that the absorbent (1) was changed to the absorbent (4).

<Production Example 5 of Absorbent Body> An absorber (5) was obtained in the same manner as in Production Example 1 except that the absorbent (1) was changed to the absorbent (5).

<Production Example 6 of Absorbent Body> An absorber (6) was obtained in the same manner as in Production Example 1 except that the absorbent (1) was changed to the absorbent (6).

<Production Example 7 of Absorber> An absorber (7) was obtained in the same manner as in Production Example 1 except that the absorbent (1) was changed to the absorbent (7).

<Production Example 8 of Absorbent Body> An absorber (8) was obtained in the same manner as in Production Example 1 except that 12 parts of the absorbent (1) was changed to 10 parts.

<Production Example 9 of Absorbent Body> An absorber (9) was obtained in the same manner as in Production Example 1 except that 12 parts of absorbent cotton was changed to 9 parts.

<Production Example 10 of Absorbent Body> 6 parts of 12 parts of absorbent cotton
Absorber (1
0) was obtained.

<Production Example 11 of Absorbent Body> Absorbent (1) 12
An absorber (11) was obtained in the same manner as in Production Example 1 except that 6 parts were used and 10 parts of absorbent cotton was changed to 5 parts.

<Production Example 12 of Absorbent Body> Absorbent (1) 12
An absorber (12) was obtained in the same manner as in Production Example 1 except that the parts were changed to 5 parts of the absorbent (5) and 10 parts of absorbent cotton was changed to 6 parts.

<Comparative Production Example 1 of Absorbent Body> Absorbent (1) 1
A comparative absorber (13) was obtained in the same manner as in Production Example 1 except that 2 parts was changed to 10 parts for the comparative absorbent (8).

<Comparative Production Example 2 of Absorbent Body> Comparative example 2 was prepared in the same manner as in Production Example 1 except that the absorbent (1) was changed to a comparative absorbent (9) and 12 parts of absorbent cotton was changed to 9 parts. Absorbent (14) of was obtained.

<Comparative Production Example 3 of Absorber> Absorbent (1) 1
2 parts were changed to 12 parts of absorbent (9) for comparison, and absorbent cotton 1
A comparative absorber (15) was obtained in the same manner as in Production Example 1 except that 2 parts was changed to 20 parts.

Using these absorbers (1) to (15),
Absorbent articles (1) to (11) and comparative absorbent articles (12) to (14) were produced as follows. <Production Example 1 of absorbent article> 40 μm thick polypropylene film (15 cm × 4) as a liquid impermeable back sheet
5 cm) on which the absorber (1) is placed, and a 100 μm-thick polyethylene terephthalate nonwoven fabric (15 cm × 45 cm) as a liquid-permeable surface sheet is placed thereon,
An absorbent article (1) was obtained by hot pressing each side with a width of 1 cm.

<Production Example 2 of Absorbent Article> An absorbent article (2) was obtained in the same manner as in Production Example 1 except that the absorbent body (1) was changed to the absorbent body (2).

<Production Example 3 of Absorbent Article> An absorbent article (3) was obtained in the same manner as in Production Example 1 except that the absorbent body (1) was changed to the absorbent body (3).

<Production Example 4 of Absorbent Article> An absorbent article (4) was obtained in the same manner as in Production Example 1 except that the absorbent body (1) was changed to the absorbent body (4).

<Production Example 5 of Absorbent Article> An absorbent article (5) was obtained in the same manner as in Production Example 1 except that the absorbent body (1) was changed to the absorbent body (5).

<Production Example 6 of Absorbent Article> An absorbent article (6) was obtained in the same manner as in Production Example 1 except that the absorbent body (1) was changed to the absorbent body (6).

<Production Example 7 of Absorbent Article> An absorbent article (7) was obtained in the same manner as in Production Example 1 except that the absorbent body (1) was changed to the absorbent body (7).

<Production Example 8 of Absorbent Article> An absorbent article (8) was obtained in the same manner as in Production Example 1 except that the absorbent body (1) was changed to the absorbent body (8).

<Production Example 9 of Absorbent Article> An absorbent article (9) was obtained in the same manner as in Production Example 1 except that the absorbent body (1) was changed to the absorbent body (9).

<Production Example 10 of absorbent article> Absorber (1)
An absorbent article (10) was obtained in the same manner as in Production Example 1, except that the absorbent body was changed to the absorbent body (10).

<Production Example 11 of absorbent article> The absorbent body (11) was placed on a polypropylene film (15 cm × 45 cm) having a thickness of 40 μm as a liquid impermeable back sheet,
By arranging an absorber (12) on it, and further arranging a polyethylene terephthalate non-woven fabric (15 cm × 45 cm) having a thickness of 100 μm as a liquid-permeable surface sheet on it, by heat-pressing each side with a width of 1 cm. An absorbent article (11) was obtained.

<Comparative Production Example 1 of Absorbent Article> A comparative absorbent article (12) was obtained in the same manner as in Production Example 1 except that the absorbent body (1) was changed to the comparative absorbent body (13). .

<Comparative Production Example 2 of Absorbent Article> A comparative absorbent article (13) was obtained in the same manner as in Production Example 1 except that the absorbent body (1) was changed to the comparative absorbent body (14). .

<Comparative Production Example 3 of Absorbent Article> A comparative absorbent article (14) was obtained in the same manner as in Production Example 1 except that the absorbent body (1) was changed to the comparative absorbent body (15). .

With respect to these absorbent articles (1) to (14), the SDME surface dryness, the leak resistance and the thickness of the absorbent article were evaluated, and the results are shown in Table 1. The thickness of the absorbent article was measured by the following method. <Measurement method of thickness of absorbent article> Acrylic plate (150 mm
× 450 mm × thickness 10 mm, weight 785 g), the absorbent article is arranged on the acrylic plate (150
(mm × 450 mm × thickness 4 mm, weight 785 g) was placed, and after 1 minute, the thickness of the absorbent article was determined by measuring the distance between the two acrylic plates.

[0125]

[Table 1]

Note) Content of absorbent (%) = (weight of absorbent) × 100 / {(weight of absorbent) + (weight of fibrous material)} The absorbent articles (1) to (11) produced with the content of 40% by weight or more based on the weight of the absorber (absorbent / fibrous material) have excellent dryness and leak resistance under normal pressure. showed that. Further, the thickness of the absorbent article is also extremely thin as compared with the absorbent article (14) prepared with the content of the absorbent being less than 40% by weight based on the weight of the absorber (absorbent / fibrous material). A mold was obtained. On the other hand, using a conventional absorbent, the content of the absorbent is 40% by weight based on the weight of the absorbent body (absorbent / fibrous material).
The absorbent articles (12) to (13) created as above are
A gel blocking phenomenon occurred, and excellent dryness and leak resistance under normal pressure were not obtained.

[0127]

EFFECTS OF THE INVENTION Even if the content of the absorbent of the present invention is 40% by weight or more based on the weight of the absorbent body (absorbent / fibrous material), the gel blocking phenomenon is extremely unlikely to occur. By using this absorbent, it is possible to produce an ultrathin absorbent article. Furthermore, the ultrathin absorbent article using the absorbent of the present invention exhibits extremely excellent absorption performance (surface dryness under normal pressure, anti-leakage property, and diffusibility). Therefore, the absorbent of the present invention enables the absorbent article to be made extremely thin, and can significantly reduce the discomfort and discomfort felt when the absorbent article is used.

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 3B029 BA18                 4C003 AA23                 4C098 AA09 CC07 DD05 DD23                 4J002 AB012 AB031 AB042 AB052                       AD012 AD022 AD032 BB181                       BE021 BE022 BG011 BG072                       BG102 BN171 CF032 CH022                       FA046 FD010 FD050 FD070                       FD090 FD180 GB01 GC00

Claims (9)

[Claims] 1. A water-absorbent resin (A) having a number average molecular weight of 5
An absorbent comprising a water-soluble resin (B) of 00 or more and 2,000,000 or less. 2. The absorbent according to claim 1, wherein the water-soluble resin (B) has a solubility parameter of 8.0 or more and 20.0 or less. 3. The absorbent according to claim 1, wherein the water-soluble resin (B) is a nonionic water-soluble resin. 4. The absorbent according to claim 1, wherein the water-soluble resin (B) is a polyoxyalkylene group-containing compound. 5. The content of the water-soluble resin (B) is 0.05% by weight or more and 20.0% or more based on the weight of the water absorbent resin (A).
The absorbent according to any one of claims 1 to 4, which is not more than wt%. 6. An absorbent body comprising the absorbent according to any one of claims 1 to 5 and a fibrous material as essential constituent components. 7. The absorbent body according to claim 6, wherein the content of the absorbent is 40.0% by weight or more and 99.9% by weight or less based on the total weight of the absorbent and the fibrous material. 8. An absorbent article comprising the absorbent body according to claim 6 or 7 as an essential constituent component. 9. The SDME surface dryness (DS) is 4
The absorbent article according to claim 8, which is 0% or more and 100% or less. <SDME surface dryness (DS) measurement method> A cylindrical cylinder having an inner diameter of 6.0 cm and a height of 3.8 cm is placed on the central portion of the measurement sample arranged on a horizontal plane, and 160 ml of physiological saline is poured into the cylindrical cylinder. Immediately after the liquid is removed and the cylindrical cylinder is removed, the central part of the measurement sample is irradiated with visible light from the surface layer of the measurement sample from the 45 ° direction, and the intensity of the light reflected from the surface layer of the measurement sample in the 90 ° direction is measured. Calculation is performed by measuring the light intensity (Is) 7 minutes after the cylindrical cylinder is removed.