JP2014108165A - Absorber and absorbent article using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thin type absorber having high absorption performance and excellent texture.SOLUTION: An absorber 2 includes an absorber layer 26 containing water absorptive resin powder 6 that satisfies the following requirements (a)-(d), and fabricated by an air lay method, where a mass ratio of the water absorptive resin powder 6 is not less than 65.0 mass% and not more than 95.2 mass% with respect to the total mass of the absorber layer 26. The water absorptive resin powder has (a) a bulk density of 0.45 g/ml-0.62 g/ml, (b) an absorption rate by a vortex method of 20-50 sec., (c) liquid permeation speed of 10 sec. or less under load, and (d) a moisture absorption blocking ratio of 5% or less.

Description

  The present invention relates to an improvement technique for thinning absorbent articles such as disposable diapers and sanitary napkins.

  Absorbent articles such as disposable diapers, sanitary napkins, and incontinence pads are designed to absorb and retain body fluids such as urine and menstrual blood excreted from the body, and flexible liquid permeation placed on the side in contact with the body. And a liquid-impermeable back sheet disposed on the side opposite to the side in contact with the body. The absorber is generally composed of a hydrophilic fibrous base material such as wood pulp and a water absorbent resin powder. The body fluid passes through the surface sheet made of a nonwoven fabric or the like and is absorbed by the absorber. The absorbed body fluid is diffused by a fibrous base material such as wood pulp inside the absorber, and is absorbed and held in the water absorbent resin powder.

  Patent Documents 1 to 4 propose water-absorbing resin powders that can be used for the absorber. Patent Document 1 includes a water-soluble vinyl monomer (a1) and / or a hydrolyzable vinyl monomer (a2), and a crosslinked polymer (A1) having a crosslinking agent (b) as essential constituent units, and absorbent resin particles. The hydrophobic substance (C) is present in an amount of 0.01 to 10.0% by weight based on the weight of the crosslinked polymer (A1), and the hydrophobic substance (D) is present on the surface of the absorbent resin particles. Absorbent resin particles are disclosed which are present in an amount of 0.001 to 1.0% by weight with respect to the weight of (A1).

  Patent Document 2 discloses a reaction mixture containing water-absorbing water-absorbing resin particles (a) obtained by subjecting a water-soluble ethylenically unsaturated monomer aqueous solution containing a crosslinking agent to reverse phase suspension polymerization in a hydrophobic organic solvent in the presence of a dispersant. A first step of obtaining (A); a reaction mixture containing water-absorbing water-absorbing resin particles (b) by adding a water-soluble ethylenically unsaturated monomer aqueous solution further containing a cross-linking agent to reverse phase suspension polymerization to (A); A second step of obtaining (B); a third step of dehydrating and desolvating the (B) to obtain a water absorbent resin cake (C); and a fourth step of drying the water absorbent resin cake. It is a manufacturing method of particle | grains (D), Comprising: The bulk density of the water-containing water absorbing resin particle (b) is 0.25-0.35 g / ml, and the bulk density of the water absorbing resin particle (D) after drying is 0. A method for producing water-absorbing resin particles of 45 to 0.55 g / ml is disclosed.

  Patent Document 3 discloses a water absorbent resin (A) having a gel flow rate (ml / min) of 0.01 to 3 and a water absorbent resin having a gel flow rate (ml / min) of 5 to 200. An absorbent article comprising (a) is disclosed.

  Patent Document 4 contains a water-absorbent resin (A) and a modifier (B) having a surface tension of 10 to 30 dynes / cm and having a bonding group capable of chemically bonding to (A). A water-absorbing resin composition is disclosed.

  By the way, in order to make an absorbent article compact, it is required to make the absorber thin. For example, Patent Documents 5 and 6 propose a thin absorber.

For example, Patent Document 5 discloses a liquid-absorbent sheet having a layer configuration of a pulp-based liquid-absorbing surface material / liquid-absorbing nonwoven fabric / pulp-based liquid-absorbing back material, and containing a superabsorbent polymer. The total weight of the liquid absorbent sheet is 300 to 600 g / m ² , the total amount of the superabsorbent polymer is 200 to 400 g / m ² , and at least the liquid absorbent surface material layer and the liquid absorbent nonwoven layer And a layer between the liquid-absorbing nonwoven fabric layer and the pulp-based liquid-absorbing back material layer, and the superabsorbent polymer is between the pulp-based liquid-absorbing surface material and the liquid-absorbing nonwoven fabric. 30 to 50% by mass in (A layer), 30 to 70% by mass between the liquid-absorbing nonwoven fabric and the pulp-based liquid-absorbing back material (B layer), and 0 to 40% by mass in the liquid-absorbing nonwoven layer. Blended in proportion and blending ratio of superabsorbent polymer in layer A The liquid absorbent sheet, wherein it is disclosed that satisfies the relationship of blending ratio of the superabsorbent polymer B layer.

For example, Patent Document 6 discloses an absorbent body that includes a superabsorbent polymer and an absorbent fiber and is thinned by pressurization, and the superabsorbent polymer has a gel modulus of elasticity of 2000 N according to a gel modulus test. / M ² or more and the absorption of artificial urine under a pressure of 20 g / cm ^{2 in the} absorption test under pressure is 32 cc / g or more, and the superabsorbent polymer with respect to the total weight of the superabsorbent polymer and the absorbent fibers An absorbent body characterized in that the ratio of is 40% by weight or more is disclosed.

JP 2010-185029 A JP 2010-59254 A JP 2003-235889 A JP 2003-82250 A JP 2007-136162 A JP 2002-172139 A

  As disclosed in Patent Documents 5 and 6, it is known to produce a thin absorber by an air array method (sometimes referred to as an “air array method”). However, the absorber produced by the air array method has a high material density such as a water-absorbent resin powder and a fiber base material, and thus the absorption performance is lowered. Specifically, the absorption rate and the absorption amount are reduced, or the body fluid is reversed. Moreover, there exists a problem that an absorber becomes hard and a texture falls by being thinned. The present invention has been made in view of the above circumstances, and an object thereof is to provide a thin absorbent body having high absorption performance. Another object of the present invention is to provide an absorbent body having a good texture.

The absorber of the present invention contains an absorbent resin powder that satisfies the following requirements (a) to (d) and has an absorbent layer produced by an air laying method, A mass ratio is 65.0 mass% or more and 95.2 mass% or less with respect to the total mass of the said absorption layer, It is characterized by the above-mentioned.
(A) Bulk density: 0.45 g / ml to 0.62 g / ml
(B) Absorption speed by vortex method: 20 seconds to 50 seconds (c) Liquid passing speed under load: 10 seconds or less (d) Moisture absorption blocking ratio: 5% or less The absorber of the present invention comprises the following (a) to (d And a water-absorbing resin powder that satisfies the requirements (1), and has an absorbent layer prepared by the air-laying method. A large amount of water-absorbing resin powder can be contained in the absorbing layer by preparing the absorbing layer by the air array method. Therefore, the absorption performance of the obtained absorber improves. Moreover, the water-absorbent resin powder used in the present invention is configured as described above, so that body fluid can be quickly dispersed and absorbed. As a result, even when used in an absorbent layer having a high material density, such as a water-absorbent resin powder or a short fiber machine, an absorbent body having a high penetration rate and excellent dry feeling on the surface of the absorbent body can be obtained.

  The water-absorbent resin powder preferably has an absorption capacity of 40 g / g to 55 g / g and a water retention amount of 20 g / g to 45 g / g from the viewpoint of expressing high water absorption.

  Examples of the water-absorbent resin powder include (a1) a water-soluble ethylenically unsaturated monomer and / or (a1) a hydrolyzable monomer that becomes a water-soluble ethylenically unsaturated monomer by hydrolysis, and (b) A water-absorbing resin powder obtained by treating (A) a crosslinked polymer obtained by polymerizing a monomer composition containing an internal crosslinking agent with (B) a surface modifier is preferable. It is preferable that the processing amount of (B) surface modifier is 0.001 mass part-1 mass part with respect to 100 mass parts of (A) crosslinked polymer. (B) The surface modifier is preferably at least one selected from the group consisting of amino-modified polysiloxane, carboxy-modified polysiloxane, and silica.

The absorbent body of the present invention preferably includes a liquid-permeable first sheet and a second sheet, and a pre-absorbing layer is disposed between the first sheet and the second sheet. Basis weight of the water-absorbent resin powder of the absorbent layer ^is preferably ^{150g / m 2 ~500g / m 2} . The thickness of the absorber is preferably 0.5 mm to 5 mm.

  The absorber is preferably treated with a polyglycerin having a polymerization degree of 1 to 10 or a fatty acid ester thereof, or a polyalkylene glycol having a polymerization degree of 1 to 20 or a fatty acid ester thereof as a texture modifier. It is preferable that the processing amount of a texture modifier is 0.05 mass part-5.00 mass parts with respect to 100 mass parts of an untreated absorber.

  The present invention includes an absorbent article comprising the absorber.

  According to the present invention, a thin absorbent body having a high content of water-absorbent resin powder can be provided. The absorbent body and absorbent article of the present invention have a high penetration rate and an excellent dry feeling. The absorbent body of the present invention is soft and has a good texture.

Explanatory drawing which shows typically an example of the manufacturing apparatus of the absorber of this invention. Explanatory drawing which shows typically the other example of the manufacturing apparatus of the absorber of this invention. The top view of the absorbent article of preferable embodiment of this invention. Sectional drawing in the II line | wire of FIG. Sectional drawing in the II-II line | wire of FIG.

The absorber of the present invention contains an absorbent resin powder that satisfies the following requirements (a) to (d) and has an absorbent layer produced by an air laying method, A mass ratio is 65.0 mass% or more and 95.2 mass% or less with respect to the total mass of the said absorption layer, It is characterized by the above-mentioned.
(A) Bulk density: 0.45 g / ml to 0.62 g / ml
(B) Absorption speed by vortex method: 20 seconds to 50 seconds (c) Liquid passing speed under load: 10 seconds or less (d) Hygroscopic blocking ratio: 5% or less

  First, the water absorbent resin powder used in the present invention will be described. The water absorbent resin powder (a) has a bulk density of 0.45 g / ml to 0.62 g / ml. The bulk density of the water absorbent resin powder is preferably 0.50 g / ml or more, more preferably 0.52 g / ml or more, and preferably 0.61 g / ml or less, 0.60 g / Ml or less is more preferable. The bulk density is an index of the shape of the water absorbent resin powder. If the bulk density is within the above range, a void as a body fluid passage is easily formed between the water-absorbent resin powders. As a result, the absorption rate and the repeated absorption rate are improved. A method for measuring the bulk density will be described later.

  The water-absorbent resin powder has an absorption rate of 20 seconds to 50 seconds by (b) vortex method. The absorption rate of the water-absorbent resin powder by the vortex method is preferably 22 seconds or more, more preferably 25 seconds or more, preferably 48 seconds or less, and more preferably 45 seconds or less. . When the absorption rate exceeds 50 seconds, the bodily fluid excretion rate is high, and when a large amount of bodily fluid is excreted at a time, the bodily fluid cannot be sufficiently absorbed. As a result, liquid leakage tends to occur. The smaller the absorption rate, the better. However, if it is less than 20 seconds, the stability of the water-absorbent resin powder to urine, particularly the stability under load, may be lowered. The absorption speed by the vortex method is evaluated by measuring the time (seconds) to absorb the body fluid. Therefore, the shorter the measurement time (second), the greater the absorption rate.

  The water-absorbent resin powder (c) has a liquid passage speed under load of 10 seconds or less. The liquid passing speed under load is preferably 8 seconds or less, and more preferably 5 seconds or less. When the liquid passing speed under the load exceeds 10 seconds, diffusion of body fluid is likely to occur inside the absorber. For this reason, liquid leakage may occur easily. The liquid passing speed under load is evaluated by measuring a time (second) through which a certain amount of liquid passes in a state where a load is applied to the water-absorbent resin powder swollen by absorbing water in advance. Therefore, the shorter the measurement time (second), the greater the absorption rate.

  The water absorbent resin powder (d) has a moisture absorption blocking rate of 5% or less. The moisture absorption blocking rate is more preferably 4% or less, and further preferably 3% or less. If the moisture absorption blocking rate exceeds 5%, the water absorbent resin powder tends to aggregate. Therefore, when manufacturing an absorber, the water-absorbing resin powder is easily clogged in a transport pipe in a manufacturing machine or a manufacturing line, or the water-absorbing resin powder cannot be uniformly applied to the nonwoven fabric. In addition, the excreted body fluid may easily return.

  The water absorbent resin powder preferably has an absorption capacity of 40 g / g or more, more preferably 42 g / g or more, further preferably 44 g / g or more, and 55 g / g or less. Is preferably 53 g / g or less, and more preferably 51 g / g or less. The absorption ratio is a scale indicating how much water absorbent resin powder can absorb water. If the absorption ratio is less than 40 g / g, a large amount of water-absorbing resin powder must be used to keep the absorption capacity at a predetermined level, making it difficult to produce a thin absorbent body. From the standpoint of preventing liquid leakage, the absorption ratio is preferably as large as possible, but more preferably 55 g / g or less. This is because if the absorption ratio exceeds 55 g / g, the stability of the water-absorbent resin powder to urine tends to decrease.

  The water-absorbent resin powder has a water retention amount of preferably 20 g / g or more, more preferably 22 g / g or more, further preferably 24 g / g or more, preferably 45 g / g or less, more preferably 43 g / g or less, 40 g / G or less is more preferable. The water retention amount is a scale indicating how much the liquid absorbed by the water absorbent resin powder can be retained. If the water retention amount is less than 20 g / g, a large amount of water-absorbing resin powder must be used to maintain the body fluid retention capacity at a predetermined level, making it difficult to produce a thin absorbent body. There is a case. The water retention amount is preferably as large as possible from the viewpoint of preventing liquid leakage, but is more preferably 45 g / g or less. This is because when the water retention amount exceeds 45 g / g, the stability of the water-absorbent resin powder to urine tends to decrease.

  The bulk density of the water-absorbent resin powder, the absorption speed by the vortex method, the liquid passing speed under load, the absorption capacity, the water retention amount, for example, the composition of the cross-linked polymer, the type of surface modifier, the particle size of the water-absorbent resin powder, and the drying It can be adjusted by appropriately selecting conditions and the like.

  The water-absorbent resin powder is preferably obtained by treating the surface of (A) a crosslinked polymer with (B) a surface modifier. (A) The crosslinked polymer comprises (a1) a water-soluble ethylenically unsaturated monomer and / or hydrolyzing (a1) a water-soluble ethylenically unsaturated monomer (a2) a hydrolyzable monomer, and (b) It is preferably obtained by polymerizing a monomer composition containing an internal crosslinking agent as an essential component.

  First, (A) a crosslinked polymer will be described. (A1) The water-soluble ethylenically unsaturated monomer is not particularly limited, and a monomer having at least one water-soluble substituent and an ethylenically unsaturated group can be used. The water-soluble monomer means a monomer having a property of dissolving at least 100 g in 100 g of water at 25 ° C. The (a2) hydrolyzable monomer is hydrolyzed by the action of 50 ° C. water and, if necessary, a catalyst (acid or base) to produce (a1) a water-soluble ethylenically unsaturated monomer. (A2) Hydrolysis of the hydrolyzable monomer may be any of (A) during the polymerization of the crosslinked polymer, after the polymerization, and after polymerization, from the viewpoint of the molecular weight of the resulting water-absorbent resin powder, etc. Is preferred.

  Examples of the water-soluble substituent include a carboxyl group, a sulfo group, a sulfooxy group, a phosphono group, a hydroxyl group, a carbamoyl group, an amino group, or a salt thereof, and an ammonium salt. A salt of a carboxyl group (carboxylate) ), A salt of a sulfo group (sulfonate), and an ammonium salt. Examples of the salt include alkali metal salts such as lithium, sodium and potassium, and alkaline earth metal salts such as magnesium and calcium. The ammonium salt may be either a primary to tertiary amine salt or a quaternary ammonium salt. Of these salts, alkali metal salts and ammonium salts are preferable, alkali metal salts are more preferable, and sodium salts are more preferable from the viewpoint of absorption characteristics.

  The water-soluble ethylenically unsaturated monomer having a carboxyl group and / or a salt thereof is preferably an unsaturated carboxylic acid having 3 to 30 carbon atoms and / or a salt thereof. Specific examples of the water-soluble ethylenically unsaturated monomer having a carboxyl group and / or a salt thereof include unsaturated monocarboxylic acids such as (meth) acrylic acid, (meth) acrylic acid salt, crotonic acid and cinnamic acid and / or Or a salt thereof; unsaturated dicarboxylic acid such as maleic acid, maleate, fumaric acid, citraconic acid and itaconic acid and / or a salt thereof; maleic acid monobutyl ester, fumaric acid monobutyl ester, ethyl carbitol mono of maleic acid Examples thereof include monoalkyl (carbon number 1 to 8) esters and / or salts of unsaturated dicarboxylic acids such as esters, ethyl carbitol monoester of fumaric acid, citraconic acid monobutyl ester, and itaconic acid glycol monoester. In the description of the present invention, “(meth) acryl” means “acryl” and / or “methacryl”.

  The water-soluble ethylenically unsaturated monomer having a sulfo group and / or a salt thereof is preferably a sulfonic acid having 2 to 30 carbon atoms and / or a salt thereof. Specific examples of the water-soluble ethylenically unsaturated monomer having a sulfo group and / or a salt thereof include aliphatic groups such as vinyl sulfonic acid, (meth) allyl sulfonic acid, styrene sulfonic acid, and α-methyl styrene sulfonic acid, or Aromatic vinyl sulfonic acid; (meth) acryloxypropyl sulfonic acid, 2-hydroxy-3- (meth) acryloxypropyl sulfonic acid, 2- (meth) acryloylamino-2,2-dimethylethanesulfonic acid, 3- ( (Meth) acryloyl-containing alkylsulfonic acids such as (meth) acryloxyethanesulfonic acid, 2- (meth) acrylamide-2-methylpropanesulfonic acid, and 3- (meth) acrylamide-2-hydroxypropanesulfonic acid; and alkyl (Meth) allylsulfosuccinate It is.

  Examples of the water-soluble ethylenically unsaturated monomer having a sulfooxy group and / or a salt thereof include hydroxyalkyl (meth) acrylate sulfate ester; polyoxyalkylene mono (meth) acrylate sulfate ester and the like.

  Water-soluble ethylenically unsaturated monomers having a phosphono group and / or a salt thereof include phosphoric acid monoester of hydroxyalkyl (meth) acrylate, phosphoric diester of hydroxyalkyl (meth) acrylate, and (meth) acrylic Examples thereof include alkylphosphonic acid.

  Examples of the water-soluble ethylenically unsaturated monomer having a hydroxyl group include (meth) allyl alcohol and monoethylenically unsaturated alcohol having 3 to 15 carbon atoms such as (meth) propenyl alcohol; alkylene glycol having 2 to 20 carbon atoms, Monoethylenically unsaturated carboxylic acid ester or monoethylenic unsaturated ester of 2-6 valent polyol such as glycerin, sorbitan, diglycerin, pentaerythritol, polyalkylene (2 to 4 carbon atoms) glycol (weight average molecular weight 100 to 2000) Saturated ether and the like are included. Specific examples thereof include hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, triethylene glycol (meth) acrylate, poly-oxyethylene-oxypropylene mono (meth) allyl ether, and the like.

  Examples of water-soluble ethylenically unsaturated monomers having a carbamoyl group include (meth) acrylamide; N-alkyl (1 to 8 carbon atoms) (meth) acrylamide such as N-methylacrylamide; N, N-dimethylacrylamide, N, N N-N-dialkyl (alkyl having 1 to 8 carbon atoms) acrylamide such as di-n- or i-propyl acrylamide; N-hydroxyalkyl such as N-methylol (meth) acrylamide and N-hydroxyethyl (meth) acrylamide (C1-C8) (meth) acrylamide; N, N-dihydroxyalkyl (C1-C8) (meth) acrylamide, such as N, N-dihydroxyethyl (meth) acrylamide, is mentioned. In addition to these, as the unsaturated monomer having a group consisting of amide, a vinyl lactam having 5 to 10 carbon atoms (such as N-vinylpyrrolidone) can also be used.

  Examples of the water-soluble ethylenically unsaturated monomer having an amino group include an amino group-containing ester of monoethylenically unsaturated mono- or di-carboxylic acid and an amino group-containing amide of monoethylenically unsaturated mono- or di-carboxylic acid. Is mentioned. As the amino group-containing ester of monoethylenically unsaturated mono- or di-carboxylic acid, dialkylaminoalkyl (meth) acrylate, di (hydroxyalkyl) aminoalkyl ester and morpholinoalkyl ester can be used, and dimethylaminoethyl (meta ) Acrylate, diethylamino (meth) acrylate, morpholinoethyl (meth) acrylate, dimethylaminoethyl fumarate, dimethylaminoethyl malate and the like. The amino group-containing amide of monoethylenically unsaturated mono- or di-carboxylic acid is preferably monoalkyl (meth) acrylamide, and examples thereof include dimethylaminoethyl (meth) acrylamide and diethylaminoethyl (meth) acrylamide. As the water-soluble ethylenically unsaturated monomer having an amino group, vinyl pyridine such as 4-vinyl pyridine and 2-vinyl pyridine can also be used.

  Hydrolysis (a1) Generates a water-soluble ethylenically unsaturated monomer (a2) The hydrolyzable monomer is not particularly limited, but has at least one hydrolyzable substituent that becomes a water-soluble substituent by hydrolysis. Ethylenically unsaturated monomers are preferred. Examples of the hydrolyzable substituent include a group containing an acid anhydride, a group containing an ester bond, and a cyano group.

  Examples of the ethylenically unsaturated monomer having a group containing an acid anhydride include unsaturated dicarboxylic acid anhydrides having 4 to 20 carbon atoms such as maleic anhydride, itaconic anhydride, and citraconic anhydride. Examples of the ethylenically unsaturated monomer having a group containing an ester bond include lower alkyl esters of monoethylenically unsaturated carboxylic acids such as methyl (meth) acrylate and ethyl (meth) acrylate; and vinyl acetate, acetic acid And esters of monoethylenically unsaturated alcohols such as (meth) allyl. Examples of the ethylenically unsaturated monomer having a cyano group include (meth) acrylonitrile and nitrile compounds containing a vinyl group having 3 to 6 carbon atoms such as 5-hexenenitrile.

  As (a1) water-soluble ethylenically unsaturated monomer and (a2) hydrolyzable monomer, further, Japanese Patent No. 3648553, Japanese Patent Application Laid-Open No. 2003-165883, Japanese Patent Application Laid-Open No. 2005-75982, and Japanese Patent Application Laid-Open No. 2005-2005. The thing of -95759 gazette can be used.

  (A1) The water-soluble ethylenically unsaturated monomer and (a2) hydrolyzable monomer may be used alone or as a mixture of two or more. The same applies when (a1) a water-soluble ethylenically unsaturated monomer and (a2) a hydrolyzable monomer are used in combination. When (a1) a water-soluble ethylenically unsaturated monomer and (a2) a hydrolyzable monomer are used in combination, the content molar ratio (a1 / a2) is preferably 75/25 to 99/1, more preferably 85/15 to 95/5, more preferably 90/10 to 93/7, and most preferably 91/9 to 92/8. When the content molar ratio is within the above range, the absorption performance is further improved.

  (A) As a monomer constituting the crosslinked polymer, (a1) a water-soluble ethylenically unsaturated monomer and (a2) a hydrolyzable monomer, (a3) other vinyl monomers copolymerizable with these are used. be able to. As the copolymerizable (a3) other vinyl monomer, a hydrophobic vinyl monomer or the like can be used, but is not limited thereto. (A3) As other vinyl monomers, the following vinyl monomers (i) to (iii) are used.

(I) an aromatic ethylenic monomer having 8 to 30 carbon atoms;
Styrene such as styrene, α-methylstyrene, vinyltoluene and hydroxystyrene, and halogen substituted products of styrene such as vinylnaphthalene and dichlorostyrene.
(Ii) an aliphatic ethylene monomer having 2 to 20 carbon atoms;
Alkenes such as ethylene, propylene, butene, isobutylene, pentene, heptene, diisobutylene, octene, dodecene and octadecene; and alkadienes such as butadiene and isoprene.

(Iii) an alicyclic ethylene monomer having 5 to 15 carbon atoms;
Monoethylenically unsaturated monomers such as pinene, limonene and indene; and polyethylene vinyl polymerizable monomers such as cyclopentadiene, bicyclopentadiene and ethylidene norbornene.

  (A3) As other vinyl monomers, those described in Japanese Patent No. 3648553, Japanese Patent Application Laid-Open No. 2003-165883, Japanese Patent Application Laid-Open No. 2005-75982, and Japanese Patent Application Laid-Open No. 2005-95759 should be used. Can do.

  When (a3) other vinyl monomer is used, the content (mol%) of (a3) other vinyl monomer is the total amount of (a1) water-soluble ethylenically unsaturated monomer and (a2) hydrolyzable monomer (100 Mol%) is preferably 0.01 mol% to 5 mol%, more preferably 0.05 mol% to 3 mol%, still more preferably 0.08 mol% to 2 mol%, and most preferably 0.0. 1 mol% to 1.5 mol%. In view of absorption characteristics, the content of (a3) other vinyl monomer is most preferably 0 mol%.

  (B) As an internal crosslinking agent, (b1) an internal crosslinking agent having two or more ethylenically unsaturated groups, (b2) (a1) a water-soluble substituent of a water-soluble ethylenically unsaturated monomer and / or (a2) An internal cross-linking agent having at least one functional group capable of reacting with a water-soluble substituent formed by hydrolysis of a hydrolyzable monomer and having at least one ethylenically unsaturated group, and (b3) ( a1) a water-soluble substituent of a water-soluble ethylenically unsaturated monomer and / or (a2) an internal crosslinking agent having at least two functional groups capable of reacting with a water-soluble substituent generated by hydrolysis of a hydrolyzable monomer Can be mentioned.

  (B1) As an internal crosslinking agent having two or more ethylenically unsaturated groups, bis (meth) acrylamide having 8 to 12 carbon atoms, poly (meth) acrylate of a polyol having 2 to 10 carbon atoms, or 2 to 10 carbon atoms And poly (meth) allyl ethers of polyols having 2 to 10 carbon atoms. Specific examples thereof include N, N′-methylenebis (meth) acrylamide, ethylene glycol di (meth) acrylate, poly (degree of polymerization 2 to 5) ethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, Glycerin (di or tri) acrylate, trimethylolpropane triacrylate, diallylamine, triallylamine, triallyl cyanurate, triallyl isocyanurate, tetraallyloxyethane, pentaerythritol diallyl ether, pentaerythritol triallyl ether, pentaerythritol tetraallyl ether And diglycerin di (meth) acrylate and the like.

(B2) (a1) having at least one functional group capable of reacting with a water-soluble substituent of a water-soluble ethylenically unsaturated monomer and / or (a2) a water-soluble substituent generated by hydrolysis of a hydrolyzable monomer And as an internal cross-linking agent having at least one ethylenically unsaturated group, an ethylenically unsaturated compound having an epoxy group having 6 to 8 carbon atoms, an ethylenically unsaturated compound having a hydroxyl group having 4 to 8 carbon atoms And ethylenically unsaturated compounds having an isocyanato group having 4 to 8 carbon atoms. Specific examples thereof include glycidyl (meth) acrylate, N-methylol (meth) acrylamide, hydroxyethyl (meth) acrylate and isocyanatoethyl (meth) acrylate.

  (B3) (a1) having at least two functional groups capable of reacting with a water-soluble substituent of a water-soluble ethylenically unsaturated monomer and / or (a2) a water-soluble substituent generated by hydrolysis of a hydrolyzable monomer Examples of the internal crosslinking agent include polyhydric alcohols, polyhydric glycidyl, polyhydric amines, polyhydric aziridines and polyhydric isocyanates. Examples of the polyvalent glycidyl compound include ethylene glycol diglycidyl ether and glycerin diglycidyl ether. Examples of the polyvalent amine compound include ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, and polyethyleneimine. Examples of the polyvalent aziridine compound include Chemitite PZ-33 {2,2-bishydroxymethylbutanol-tris (3- (1-aziridinyl) propinate)} manufactured by Nippon Shokubai Chemical Industry Co., Ltd., Chemite HZ-22 {1,6- Hexamethylene diethylene urea} and chemite DZ-22 {diphenylmethane-bis-4, 4′-N, N′-diethylene urea} and the like. Examples of the polyvalent isocyanate compound include 2,4-tolylene diisocyanate and hexamethylene diisocyanate. These internal crosslinking agents may be used alone or in combination of two or more.

  (B) The internal cross-linking agent is preferably an internal cross-linking agent having 2 or more ethylenically unsaturated groups from the viewpoint of absorption performance (particularly absorption amount and absorption rate), and has 2 to 10 carbon atoms. Poly (meth) allyl ether of polyol is more preferred, triallyl cyanurate, triallyl isocyanurate, tetraallyloxyethane or pentaerythritol triallyl ether is more preferred, and pentaerythritol triallyl ether is most preferred.

  (B) As the internal crosslinking agent, those described in Japanese Patent No. 3648553, Japanese Patent Application Laid-Open No. 2003-165883, Japanese Patent Application Laid-Open No. 2005-75982, and Japanese Patent Application Laid-Open No. 2005-95759 may be further used. it can.

  (B) The content (mol%) of the internal crosslinking agent is 0.001 mol% based on the total amount (100 mol%) of (a1) the water-soluble ethylenically unsaturated monomer and (a2) hydrolyzable monomer. -5 mol% is preferable, More preferably, it is 0.005 mol%-3 mol%, More preferably, it is 0.01 mol%-1 mol%. Within this range, the absorption performance (especially the absorption amount and the absorption rate) is further improved.

  (A) As a polymerization form of a crosslinked polymer, a conventionally known method can be used, and a solution polymerization method, an emulsion polymerization method, a suspension polymerization method, and a reverse phase suspension polymerization method can be applied. Further, the shape of the polymerization solution at the time of polymerization may be a thin film shape, a spray shape, or the like. As a polymerization control method, an adiabatic polymerization method, a temperature control polymerization method, an isothermal polymerization method, or the like can be applied.

  When applying the suspension polymerization method or the reverse phase suspension polymerization method as the polymerization method, if necessary, conventionally known dispersants such as sucrose ester, phosphate ester and sorbitan ester, and poval, α-olefin- Protective colloids such as maleic anhydride copolymer and polyethylene oxide can be used. In the case of the reverse phase suspension polymerization method, polymerization can be carried out using a solvent such as cyclohexane, normal hexane, normal heptane, toluene and xylene. As the polymerization method, a solution polymerization method is preferable, and an aqueous solution polymerization method is more preferable because it is not necessary to use an organic solvent or the like and is advantageous in terms of production cost.

  The hydrogel {consisting of a crosslinked polymer and water} obtained by polymerization can be chopped as necessary. The size (longest diameter) of the gel after shredding is preferably 50 μm to 10 cm, more preferably 100 μm to 2 cm, and even more preferably 1 mm to 1 cm. Within this range, the drying property in the drying process is further improved.

  Shredding can be performed by a known method. For example, the shredding can be performed using a conventional shredding device such as a bex mill, rubber chopper, pharma mill, mincing machine, impact pulverizer, and roll pulverizer.

  When using a solvent (organic solvent, water, etc.) for the polymerization, it is preferable to distill off the solvent after the polymerization. When the solvent contains an organic solvent, the content (% by mass) of the organic solvent after distillation is preferably 0% by mass to 10% by mass, and more preferably with respect to the mass of the crosslinked polymer (100% by mass). It is 0 mass%-5 mass%, More preferably, it is 0 mass%-3 mass%, Most preferably, it is 0 mass%-1 mass%. When the content of the organic solvent is within the above range, the absorption performance (particularly the water retention amount) of the water absorbent resin powder is further improved.

  When water is contained in the solvent, the water content (% by mass) after distillation is preferably 0% by mass to 20% by mass, and more preferably 1% by mass to 10% by mass with respect to the mass (100% by mass) of the crosslinked polymer. % By mass, more preferably 2% by mass to 9% by mass, and most preferably 3% by mass to 8% by mass. When the water content (% by mass) is within the above range, the absorption performance and the breakability of the water absorbent resin powder after drying are further improved.

  In addition, the content rate and moisture of the organic solvent are an infrared moisture meter {JE400 manufactured by KETT Co., Ltd .: 120 ± 5 ° C., 30 minutes, atmospheric humidity before heating 50 ± 10% RH, lamp specification 100V, 40W } Is obtained from the weight loss of the measurement sample before and after heating.

  As a method of distilling off the solvent (including water), a method of distilling (drying) with hot air at a temperature of 80 ° C. to 230 ° C., a thin film drying method using a drum dryer or the like heated to 100 ° C. to 230 ° C., (Heating) A vacuum drying method, a freeze drying method, a drying method using infrared rays, decantation, filtration, and the like can be applied.

  (A) The crosslinked polymer can be pulverized after drying. The pulverization method is not particularly limited, and for example, a normal pulverizer such as a hammer pulverizer, an impact pulverizer, a roll pulverizer, and a shet airflow pulverizer can be used. The pulverized (A) crosslinked polymer can be adjusted in particle size by sieving or the like, if necessary.

  The weight average particle diameter (μm) of the crosslinked polymer (A) when screened as necessary is preferably 100 μm to 800 μm, more preferably 200 μm to 700 μm, still more preferably 250 μm to 600 μm, particularly preferably 300 μm to 500 μm, most preferably Preferably it is 350 micrometers-450 micrometers. (A) If the weight average particle diameter (μm) of the crosslinked polymer is within the above range, the absorption performance is further improved.

  In addition, the weight average particle diameter was measured using a low-tap test sieve shaker and a standard sieve (JIS Z8801-1: 2006), Perry's Chemical Engineers Handbook, 6th edition (McGlow Hill Book Company, 1984). , Page 21). That is, JIS standard sieves are combined in the order of 1000 μm, 850 μm, 710 μm, 500 μm, 425 μm, 355 μm, 250 μm, 150 μm, 125 μm, 75 μm and 45 μm, and a tray from the top. About 50 g of the measured particles are put in the uppermost screen and shaken for 5 minutes with a low-tap test sieve shaker. Weigh the measured particles on each sieve and the pan, and calculate the weight fraction of the particles on each sieve with the total as 100% by weight. This value is the logarithmic probability paper {the horizontal axis is the sieve aperture (particle size ), The vertical axis is plotted in the weight fraction}, a line connecting the points is drawn, and the particle diameter corresponding to the weight fraction of 50% by weight is obtained, and this is defined as the weight average particle diameter.

  Further, since the absorption performance is better when the content of fine particles is smaller, the content of fine particles of 106 μm or less (preferably 150 μm or less) in the total particles is preferably 3% by weight or less, more preferably 1% by weight or less. It is. The content of the fine particles can be determined using a plot created when determining the above weight average particle diameter.

  (A) The crosslinked polymer may be one kind or a mixture of two or more kinds.

  (B) As surface modifiers, polyvalent metal compounds such as aluminum sulfate, potassium alum, ammonium alum, sodium alum, (poly) aluminum chloride, hydrates thereof; polyethyleneimine, polyvinylamine, polyallylamine, etc. Polycation compound; inorganic fine particles; (B1) surface modifier containing a hydrocarbon group; (B2) surface modifier containing a hydrocarbon group having a fluorine atom; and (B3) a surface having a polysiloxane structure. Examples thereof include modifiers.

  Examples of the inorganic fine particles include silicon oxide, aluminum oxide, iron oxide, titanium oxide, magnesium oxide, oxides such as zirconium oxide, carbides such as silicon carbide and aluminum carbide, nitrides such as titanium nitride, and these. (For example, zeolite and talc). Of these, oxides are preferable, and silicon oxide is more preferable. The volume average particle diameter of the inorganic fine particles is preferably 10 nm to 5000 nm, more preferably 30 nm to 1000 nm, still more preferably 50 nm to 750 nm, and most preferably 90 nm to 500 nm. The volume average particle diameter is measured in a solvent by a dynamic light scattering method. Specifically, it is measured at a temperature of 25 ° C. in a solvent cyclohexane using a nanotrack particle size distribution measuring device UPA-EX150 (light source: He—Ne laser) manufactured by Nikkiso Co., Ltd.

The specific surface area of the inorganic fine particles is ^preferably 20m ² / g~400m 2 / g, more preferably ^{30m 2} / ^g~350m 2 / g, more preferably ^{40m 2} / ^g~300m 2 / g. When the specific surface area is within this range, the absorption performance is further improved. The specific surface area is measured according to JIS Z8830: 2001 (nitrogen, volume method, multipoint method).

Inorganic fine particles are easily available from the market. For example, {hereinafter, trade name (chemical composition, volume average particle diameter nm, specific surface area m ² / g)}, Aerosil 130 (silicon dioxide, 16, 130), Aerosil 200 (silicon dioxide, 12, 200), Aerosil 300 (Silicon dioxide, 7,300), Aerosil MOX80 (Silicon dioxide, 30, 80), Aerosil COK84 (Silicon dioxide, 12, 170), Aerosil OX50T (Silicon dioxide, 7, 40), Titanium oxide P25 (Titanium oxide, 20) 30) and aluminum oxide C (aluminum oxide, 13, 100) {Nippon Aerosil Co., Ltd.}; Denka fused silica F-300 (silicon dioxide, 11, 160) {Electrochemical Co., Ltd.}; Microid 850 (silicon dioxide) 13, 150) {Tokai Chemical Industries, Ltd.}; KaSP-1 (silicon dioxide, 14, 45) {Nozawa Co., Ltd.}; Cyloid 622 (silicon dioxide, 17, 350); Cyloid ED50 (silicon dioxide, 8, 400) {Grace Japan Co., Ltd.}; Admuffin SO- C1 (complex oxide, 0.1, 20) {Admatex Corporation}; Aerosil 200 (silicon dioxide, 100, 12) {Degussa AG: Germany}; Toxeal (silicon dioxide, 2.5, 120) and Leoroseal (dioxide dioxide) Silicon, 2.5, 110) {Tokuyama Co., Ltd.}; Nipseal E220A (silicon dioxide, 2.5, 130) {Nippon Silica Industry Co., Ltd.}; and Clevozole 30CAL25 (silicon oxide, 12, 200) {Clariant Japan Co., Ltd. }.

  (B1) Surface modifiers containing hydrocarbon groups include polyolefin resins, polyolefin resin derivatives, polystyrene resins, polystyrene resin derivatives, waxes, long chain fatty acid esters, long chain fatty acids and salts thereof, long chain aliphatic alcohols, In addition, a mixture of two or more of these is included.

  Examples of the polyolefin resin include polymers having a weight average molecular weight of 1,000 to 1,000,000 obtained by polymerizing olefins having 2 to 4 carbon atoms such as ethylene, propylene, isobutylene and isoprene. The content of the olefin component in the polymer is preferably at least 50% by mass in 100% by mass of the polyolefin resin. Specific examples of the polyolefin resin include polyethylene, polypropylene, polyisobutylene, poly (ethylene-isobutylene), and isoprene.

  As the polyolefin resin derivative, a polymer having a weight average molecular weight of 1,000 to 1,000,000 in which a carboxy group (—COOH), 1,3-oxo-2-oxapropylene (—COOCO—) or the like is introduced into the polyolefin resin is preferable. Specific examples include, for example, polyethylene thermal degradation products, polypropylene thermal degradation products, maleic acid modified polyethylene, chlorinated polyethylene, maleic acid modified polypropylene, ethylene-acrylic acid copolymers, ethylene-maleic anhydride copolymers, isobutylene- Examples thereof include maleic anhydride copolymers, maleated polybutadiene, ethylene-vinyl acetate copolymers, and maleated products of ethylene-vinyl acetate copolymers.

  As the polystyrene resin, a polymer having a weight average molecular weight of 1,000 to 1,000,000 can be used.

  As the polystyrene resin derivative, a polymer having styrene as an essential constituent monomer and having a weight average molecular weight of 1,000 to 1,000,000 is preferable. The content of styrene is preferably at least 50% by mass in 100% by mass of the polystyrene derivative. Specific examples of the polystyrene resin derivative include styrene-maleic anhydride copolymer, styrene-butadiene copolymer, and styrene-isobutylene copolymer.

  Examples of the wax include waxes having a melting point of 50 ° C. to 200 ° C. such as paraffin wax, beeswax, carbana wax and beef tallow.

  As the long-chain fatty acid ester, an ester of a fatty acid having 8 to 30 carbon atoms and an alcohol having 1 to 12 carbon atoms is preferable. Specific examples of the long chain fatty acid ester include methyl laurate, ethyl laurate, methyl stearate, ethyl stearate, methyl oleate, ethyl oleate, glycerin lauric acid monoester, glycerin stearic acid monoester, glycerin oleic acid monoester Esters, pentaerythritol lauric acid monoester, pentaerythritol stearic acid monoester, pentaerythritol oleic acid monoester, sorbit lauric acid monoester, sorbit stearic acid monoester, sorbit oleic acid monoester, sucrose palmitic acid monoester Sucrose palmitate diester, sucrose palmitate triester, sucrose stearate monoester, sucrose stearate diester, sucrose stearate triestes Such as Le, and beef tallow and the like. Of these, sucrose stearate monoester, sucrose stearate diester, and sucrose stearate triester are preferable from the viewpoint of leakage resistance of the absorbent article, and more preferably sucrose stearate monoester and sucrose stearate. Acid diester.

  As long chain fatty acid and its salt, a C8-C30 fatty acid and its salt are preferable. Examples of the fatty acid having 8 to 30 carbon atoms include lauric acid, palmitic acid, stearic acid, oleic acid, dimer acid, and behenic acid. The metal component of the fatty acid salt having 8 to 30 carbon atoms is preferably, for example, zinc, calcium, magnesium, or aluminum (hereinafter abbreviated as Zn, Ca, Mg, Al). Specific examples of the fatty acid salt having 8 to 30 carbon atoms include Ca palmitate, Al palmitate, Ca stearate, Mg stearate, Al stearate and the like. From the viewpoint of leakage resistance of the absorbent article, the long-chain fatty acid and its salt are preferably Zn stearate, Ca stearate, Mg stearate, Al stearate, and more preferably Mg stearate.

  Examples of the long-chain aliphatic alcohol include aliphatic alcohols having 8 to 30 carbon atoms such as lauryl alcohol, palmityl alcohol, stearyl alcohol, and oleyl alcohol. From the viewpoint of leakage resistance of the absorbent article, the long-chain aliphatic alcohol is preferably palmityl alcohol, stearyl alcohol, or oleyl alcohol, and more preferably stearyl alcohol.

  (B2) As the surface modifier containing a hydrocarbon group having a fluorine atom, perfluoroalkane, perfluoroalkene, perfluoroaryl, perfluoroalkyl ether, perfluoroalkyl carboxylic acid or a salt thereof, perfluoroalkyl alcohol , And a mixture of two or more of these.

  The perfluoroalkane is preferably an alkane having 4 to 42 fluorine atoms and 1 to 20 carbon atoms. Examples of the perfluoroalkane include trifluoromethane, pentafluoroethane, pentafluoropropane, heptafluoropropane, heptafluorobutane, nonafluorohexane, tridecafluorooctane, and heptadecafluorododecane.

  The perfluoroalkene is preferably an alkene having 4 to 42 fluorine atoms and 2 to 20 carbon atoms. Examples of the perfluoroalkene include trifluoroethylene, pentafluoropropene, trifluoropropene, heptafluorobutene, nonafluorohexene, tridecafluorooctene, and heptadecafluorododecene.

  As perfluoroaryl, aryl having 4 to 42 fluorine atoms and 6 to 20 carbon atoms is preferable. Examples of perfluoroaryl include trifluorobenzene, pentafluorotoluene, trifluoronaphthalene, heptafluorobenzene, nonafluoroxylene, tridecafluorooctylbenzene, and heptadecafluorododecylbenzene.

  The perfluoroalkyl ether is preferably an ether having 2 to 82 fluorine atoms and 2 to 40 carbon atoms. Examples of perfluoroalkyl ethers include ditrifluoromethyl ether, dipentafluoroethyl ether, dipentafluoropropyl ether, diheptafluoropropyl ether, diheptafluorobutyl ether, dinonafluorohexyl ether, ditridecafluorooctyl ether, and And diheptadecafluorododecyl ether.

  As the perfluoroalkylcarboxylic acid or a salt thereof, a carboxylic acid having 3 to 41 fluorine atoms and 1 to 21 carbon atoms or a salt thereof is preferable. Examples of perfluoroalkyl carboxylic acids or salts thereof include pentafluoroethanoic acid, pentafluoropropanoic acid, heptafluoropropanoic acid, heptafluorobutanoic acid, nonafluorohexanoic acid, tridecafluorooctanoic acid, heptadecafluorododecanoic acid, Or these metal salts are mentioned. As the metal salt, an alkali metal salt or an alkaline earth metal salt is preferable.

  The perfluoroalkyl alcohol is preferably an alcohol having 3 to 41 fluorine atoms and 1 to 20 carbon atoms. Examples of perfluoroalkyl alcohols include pentafluoroethanol, pentafluoropropanol, heptafluoropropanol, heptafluorobutanol, nonafluorohexanol, tridecafluorooctanol, heptadecafluorododecanol, and ethylene of these alcohols. Examples include oxide (1 to 20 mol per 1 mol of alcohol) adduct.

  Examples of the mixture of two or more of these include a mixture of perfluoroalkylcarboxylic acid and perfluoroalkyl alcohol. For example, a mixture of pentafluoroethanoic acid and pentafluoroethanol is preferable.

  (B3) Examples of surface modifiers having a polysiloxane structure include polydimethylsiloxane; polyether-modified polysiloxanes such as polyoxyethylene-modified polysiloxane and poly (oxyethylene oxypropylene) -modified polysiloxane; carboxy-modified polysiloxane; Examples thereof include epoxy-modified polysiloxanes; amino-modified polysiloxanes; alkoxy-modified polysiloxanes, and mixtures thereof.

  The position of the organic group (modified group) of the modified silicone such as polyether-modified polysiloxane, carboxy-modified polysiloxane, epoxy-modified polysiloxane, and amino-modified polysiloxane is not particularly limited. Either the terminal, one end of polysiloxane, or both side chain and both terminals of polysiloxane may be used. Among these, from the viewpoint of absorption characteristics, both the side chain of polysiloxane and the side chain and both ends of polysiloxane are preferred, and both the side chain and both ends of polysiloxane are more preferred.

  The organic group (modified group) of the polyether-modified polysiloxane includes a group containing a polyoxyethylene chain or a poly (oxyethylene / oxypropylene) chain. The number of oxyethylene units and / or oxypropylene units contained in the polyether-modified polysiloxane is preferably 2-40, more preferably 5-30, more preferably 7-per molecule of the polyether-modified polysiloxane. 20 is more preferable, and 10 to 15 is most preferable. Within this range, the absorption characteristics are further improved. When the oxyethylene group and the oxypropylene group are contained, the content (% by mass) of the oxyethylene group and the oxypropylene group is preferably 1% by mass to 30% by mass in 100% by mass of the polyether-modified polysiloxane. 3 mass%-25 mass% are more preferable, and 5 mass%-20 mass% are still more preferable. If the content rate of an oxyethylene group and an oxyproxylene group is in the said range, an absorption characteristic will become still more favorable.

The polyether-modified polysiloxane can be easily obtained from the market. For example, the following products {modified position, type of oxyalkylene} can be preferably exemplified.
-Shin-Etsu Chemical Co., Ltd. KF-945 {side chain, oxyethylene and oxypropylene}, KF-6020 {side chain, oxyethylene and oxypropylene}, X-22-6191 {side chain, oxyethylene and oxypropylene} X-22-4922 {side chain, oxyethylene and oxypropylene}, X-22-4272 {side chain, oxyethylene and oxypropylene}, X-22-6266 {side chain, oxyethylene and oxypropylene}

FZ-2110 {both ends, oxyethylene and oxypropylene}, FZ-2122 {both ends, oxyethylene and oxypropylene}, FZ-7006 {both ends, oxyethylene and oxypropylene}, manufactured by Toray Dow Corning Co., Ltd. FZ-2166 {both ends, oxyethylene and oxypropylene}, FZ-2164 {both ends, oxyethylene and oxypropylene}, FZ-2154 {both ends, oxyethylene and oxypropylene}, FZ-2203 {both ends, oxy Ethylene and oxypropylene} and FZ-2207 {both ends, oxyethylene and oxypropylene}

  The organic group (modified group) of the carboxy-modified polysiloxane includes a group containing a carboxy group, and the organic group (modified group) of the epoxy-modified polysiloxane includes a group containing an epoxy group. Examples of the organic group (modified group) of polysiloxane include groups containing amino groups (1, 2, and tertiary amino groups). The organic group (modified group) content (g / mol) of these modified silicones is preferably 200 to 11000, more preferably 600 to 8000, and still more preferably 1000 to 4000 as carboxy equivalent, epoxy equivalent or amino equivalent. It is. Within this range, the absorption characteristics are further improved. The carboxy equivalent is measured according to “16. Total acid value test” of JIS C2101: 1999. Moreover, an epoxy equivalent is calculated | required based on JISK7236: 2001. The amino equivalent is measured according to “8. Potentiometric titration method (base number / hydrochloric acid method)” of JIS K2501: 2003.

The carboxy-modified polysiloxane can be easily obtained from the market. For example, the following products {modified position, carboxy equivalent (g / mol)} can be preferably exemplified.
* Shin-Etsu Chemical Co., Ltd. X-22-3701E {side chain, 4000}, X-22-162C {both ends, 2300}, X-22-3710 {single end, 1450}

-BY 16-880 {side chain, 3500}, BY 16-750 {both ends, 750}, BY 16-840 {side chain, 3500}, SF8418 {side chain, 3500} manufactured by Toray Dow Corning Co., Ltd.

The epoxy-modified polysiloxane can be easily obtained from the market. For example, the following products {modified position, epoxy equivalent} can be preferably exemplified.
* Shin-Etsu Chemical Co., Ltd. X-22-343 {side chain, 525}, KF-101 {side chain, 350}, KF-1001 {side chain, 3500}, X-22-2000 {side chain, 620} X-22-2046 {side chain, 600}, KF-102 {side chain, 3600}, X-22-4741 {side chain, 2500}, KF-1002 {side chain, 4300}, X-22-3000T {Side chain, 250}, X-22-163 {both ends, 200}, KF-105 {both ends, 490}, X-22-163A {both ends, 1000}, X-22-163B {both ends, 1750}, X-22-163C {both ends, 2700}, X-22-169AS {both ends, 500}, X-22-169B {both ends, 1700}, X-22-173DX {single end, 4500} , X-22-9002 { Chain-both ends, 5000}

-Toray Dow Corning FZ-3720 {side chain, 1200}, BY16-839 {side chain, 3700}, SF8411 {side chain, 3200}, SF8413 {side chain, 3800}, SF8421 {side chain, 11000 }, BY16-876 {side chain, 2800}, FZ-3736 {side chain, 5000}, BY16-855D {side chain, 180}, BY16-8 {side chain, 3700}

The amino-modified silicone can be easily obtained from the market. For example, the following products {modified position, amino equivalent} can be preferably exemplified.
* Shin-Etsu Chemical Co., Ltd. KF-865 {side chain, 5000}, KF-864 {side chain, 3800}, KF-859 {side chain, 6000}, KF-393 {side chain, 350}, KF-860 {Side Chain, 7600}, KF-880 {Side Chain, 1800}, KF-8004 {Side Chain, 1500}, KF-8002 {Side Chain, 1700}, KF-8005 {Side Chain, 11000}, KF-867 {Side Chain, 1700}, X-22-3820W {Side Chain, 55000}, KF-869 {Side Chain, 8800}, KF-861 {Side Chain, 2000}, X-22-3939A {Side Chain, 1500} , KF-877 {side chain, 5200}, PAM-E {both ends, 130}, KF-8010 {both ends, 430}, X-22-161A {both ends, 800}, X-22-161B {both Terminal 1500 , KF-8012 {both ends, 2200}, KF-8008 {both ends, 5700}, X-22-1660B-3 {both ends, 2200}, KF-857 {side chain, 2200}, KF-8001 {side Chain, 1900}, KF-862 {side chain, 1900}, X-22-9192 {side chain, 6500}

-FZ-3707 {side chain, 1500}, FZ-3504 {side chain, 1000}, BY16-205 {side chain, 4000}, FZ-3760 {side chain, 1500}, FZ- manufactured by Toray Dow Corning Co., Ltd. 3705 {side chain, 4000}, BY16-209 {side chain, 1800}, FZ-3710 {side chain, 1800}, SF8417 {side chain, 1800}, BY16-849 {side chain, 600}, BY16-850 { Side chain, 3300}, BY 16-879B {side chain, 8000}, BY16-892 {side chain, 2000}, FZ-3501 {side chain, 3000}, FZ-3785 {side chain, 6000}, BY16-872 {Side Chain, 1800}, BY16-213 {Side Chain, 2700}, BY16-203 {Side Chain, 1900}, BY16-898 {Side Chain, 2900}, B 16-890 {side chain, 1900}, BY16-893 {side chain, 4000}, FZ-3789 {side chain, 1900}, BY16-871 {both ends, 130}, BY16-853C {both ends, 360}, BY16-853U {both ends, 450}

  Examples of these mixtures include a mixture of polydimethylsiloxane and carboxyl-modified polysiloxane, a mixture of polyether-modified polysiloxane and amino-modified polysiloxane, and the like.

  (B) As the surface modifier, from the viewpoint of absorption characteristics, (B3) a surface modifier having a polysiloxane structure and inorganic fine particles are preferable, and amino-modified polysiloxane, carboxy-modified polysiloxane, and silica are preferable. More preferred.

  (A) As a method of treating the crosslinked polymer with (B) the surface modifier, if (B) the surface modifier is treated so that it exists on the surface of the (A) crosslinked polymer, in particular It is not limited. However, (B) the surface modifier is mixed with (A) the dried polymer of the cross-linked polymer, not (A) the hydrogel of the cross-linked polymer or (A) the polymer solution before polymerizing the cross-linked polymer. It is preferable from the viewpoint of controlling the amount of the surface modifier (B) on the surface. The mixing is preferably performed uniformly.

  It is preferable that the processing amount of (B) surface modifier is 0.001 mass part-1 mass part with respect to 100 mass parts of (A) crosslinked polymer.

  The shape of the water-absorbent resin powder is not particularly limited, and examples thereof include an irregularly crushed shape, a flake shape, a pearl shape, and a rice grain shape. Among these, from the viewpoint of good entanglement with the fibrous material in the use of paper diapers and the like and no fear of dropping off from the fibrous material, an irregular crushed shape is preferable.

  The water-absorbent resin powder can be subjected to surface crosslinking as necessary. As the crosslinking agent (surface crosslinking agent) for performing the surface crosslinking, the same as the (b) internal crosslinking agent can be used. As the surface cross-linking agent, from the viewpoint of absorption performance of the water-absorbent resin powder, (b3) (a1) water-soluble substituent of water-soluble ethylenically unsaturated monomer and / or (a2) hydrolysis of hydrolyzable monomer A cross-linking agent having at least two functional groups capable of reacting with the generated water-soluble substituent is preferred, more preferably polyvalent glycidyl, more preferably ethylene glycol diglycidyl ether and glycerin diglycidyl ether, most preferably ethylene glycol di- Glycidyl ether.

  In the case of surface crosslinking, the content (% by mass) of the surface crosslinking agent is (a1) a water-soluble ethylenically unsaturated monomer and / or (a2) a hydrolyzable monomer, (b) an internal crosslinking agent, and if necessary. (A3) 0.001% by mass to 7% by mass is preferable with respect to the total mass (100% by mass) of other vinyl monomers, more preferably 0.002% by mass to 5% by mass, and still more preferably 0.003%. It is mass%-4 mass%. That is, in this case, the upper limit of the content (mass%) of the surface cross-linking agent is preferably 7 mass% based on the total mass of (a1) and / or (a2), (b) and (a3). Preferably it is 5 mass%, More preferably, it is 4 mass%, Similarly, a minimum is 0.001 mass%, More preferably, it is 0.002 mass%, More preferably, it is 0.003 mass%. When the content of the surface cross-linking agent is within the above range, the absorption performance is further improved. Surface cross-linking can be achieved by a method of spraying or impregnating a water-absorbent resin powder with an aqueous solution containing a surface cross-linking agent, followed by heat treatment (100 to 200 ° C.).

  The water-absorbent resin powder contains additives such as preservatives, fungicides, antibacterial agents, antioxidants, ultraviolet absorbers, colorants, fragrances, deodorants, inorganic powders and organic fibrous materials. Can do. Examples of the additive include those exemplified in JP2003-225565A and JP2006-131767A. When these additives are contained, the content (% by mass) of the additive is preferably 0.001% by mass to 10% by mass, more preferably based on (A) the crosslinked polymer (100% by mass). It is 0.01 mass%-5 mass%, More preferably, it is 0.05 mass%-1 mass%, Most preferably, it is 0.1 mass%-0.5 mass%.

  The absorbent layer used in the present invention contains the water-absorbent resin powder and is produced by the air lay method. With the air array method, for example, the short fibers containing the debonded heat-adhesive synthetic fibers are conveyed while being uniformly dispersed in an air stream, and the short fibers blown out from a screen having pores provided in the discharge section are, In this method, an absorbent layer is produced by dropping the metal into a metal or plastic net installed underneath and suctioning air under the net while depositing the short fibers on the net. The water-absorbent resin powder may be deposited on the plastic net together with the short fibers, or may be spread on a web layer in which only the short fibers are deposited in advance.

  As described above, the absorbent layer manufactured by the air array method is capable of randomly three-dimensionally orienting short fibers in the flow direction, width direction, and thickness direction of the absorbent layer. And since these are thermally bonded, delamination does not occur. Moreover, since the absorption layer manufactured by the air array method has good uniformity, there is less variation in performance.

  Next, the short fibers that can be used for the absorbent layer will be described. The short fiber is not particularly limited, but for example, polyester, acrylic, acrylic (vinyl chloride or vinylidene chloride copolymer), nylon, vinylon, polypropylene, polyvinyl chloride, polyethylene, vinylidene, polyurethane, aramid, polyarylate, Synthetic fibers such as polyparaphenylene benzoxazole (PBO), ethylene vinyl alcohol, acrylates, and polylactic acid; regenerated fibers such as rayon polynosic and cupra; semi-synthetic fibers such as acetate, triacetate, and promix; Examples thereof include inorganic fibers such as glass fibers, metal fibers, and carbon fibers; and natural fibers such as wool, cotton, hemp, and pulp.

  It is also preferable to use a heat-adhesive conjugate fiber as the short fiber. Examples of the heat-adhesive conjugate fiber include a core-sheath type in which a low melting point component is a sheath component and a high melting point component is a core component, one side is a low melting point component, and the other is a high melting point component. . Examples of the combination of both components of these composite short fibers include PP [polypropylene] / PE (polyethylene), PET (polyethylene terephthalate) / PE, PP / low-melting copolymer PP, PET / low-melting copolymer polyester, and the like. It is done. Here, examples of the low-melting point copolyester include polyethylene terephthalate, polypropylene terephthalate, polybutylene terephthalate, etc. as a basic skeleton, aromatic dicarboxylic acids such as isophthalic acid and 5-metal sulfoisophthalic acid, adipic acid, and sebacic acid. And a modified copolymer with an aliphatic polycarboxylic acid such as diethylene glycol, diethylene glycol, propylene glycol, 1,4-butanediol and the like. The heat-adhesive conjugate fiber is composed of polyethylene terephthalate and polyethylene, polypropylene and polyethylene, polypropylene and modified polyethylene, or polypropylene and modified polypropylene, and is preferably a side-by-side or core-sheath type conjugate fiber.

  The melting point of the thermal adhesive component which is the low melting point component is preferably 80 ° C to 180 ° C, more preferably 90 ° C to 160 ° C. When the temperature is less than 80 ° C., the heat resistance of the fiber is low, so troubles are likely to occur in the manufacturing process. .

  The short fibers preferably have a fiber length of 1 mm to 20 mm, more preferably 1 mm to 10 mm, and still more preferably 1 mm to 4 mm. When the fiber length is less than 1 mm, the effect of increasing strength and rigidity is not sufficient. On the other hand, when the fiber length exceeds 15 mm, the fibers tend to be entangled with each other, and trouble is likely to occur in the manufacturing process.

  The short fibers may be crimped or not, and may be chopped strands. When crimped, both zigzag-type two-dimensional crimped fibers and spiral-type and ohmic-type three-dimensional (three-dimensional) crimped fibers can be used.

  In the absorbent body of the present invention, the mass ratio of the water-absorbent resin powder is preferably 65.0% by mass or more, preferably 70% by mass or more, and 85% by mass with respect to the total mass of the absorption layer produced by the air array method. The above is more preferable, 95.2% by mass or less is preferable, and 93% by mass or less is more preferable. Since the absorption layer of the present invention is produced by the air array method, the content of the water absorbent resin powder can be increased as described above. As a result, the amount of absorption of the absorber increases.

  The absorbent body of the present invention preferably includes a liquid-permeable first sheet and a second sheet, and the absorbent layer is disposed between the first sheet and the second sheet.

  The said 1st sheet | seat is a sheet | seat of the side contact | abutted on a skin surface, and permeate | transmits the water | moisture content of the bodily fluid from a wearer rapidly. The liquid-permeable first sheet is preferably a liquid-permeable sheet material, for example, a nonwoven fabric formed of hydrophilic fibers. Nonwoven fabrics used as the first sheet are, for example, point bond nonwoven fabrics, air-through nonwoven fabrics, spunlace nonwoven fabrics, spunbond nonwoven fabrics, and airlaid nonwoven fabrics. Examples of hydrophilic fibers that form these nonwoven fabrics include cellulose, rayon, and cotton. Is used. In addition, as the first sheet, a liquid-permeable nonwoven fabric formed of hydrophobic fibers (for example, polypropylene, polyethylene, polyester, polyamide, nylon) whose surface is hydrophilized with a surfactant may be used.

  The second sheet may be either a liquid-permeable sheet or a liquid-impermeable sheet depending on the usage mode of the absorber. As the liquid-impervious sheet, a water-repellent or liquid-impervious non-woven fabric (for example, spunbond non-woven fabric, melt blown non-woven fabric, SMS (formed of polypropylene, polyethylene, polyester, polyamide, nylon)) Spunbond, meltblown, and spunbond nonwoven fabrics) and water-repellent or liquid-impervious plastic films are used to prevent the excretion of moisture that has reached the liquid-impervious sheet from seeping out of the absorber. To prevent. When a plastic film is used for the liquid-impermeable sheet, it is preferable to use a plastic film having moisture permeability (breathability) from the viewpoint of preventing stuffiness and improving wearer's comfort.

  The absorber of the present invention is preferably treated with a texture modifier. As an aspect of the process of a texture modifier, spray application can be mentioned, for example. Examples of the texture modifier include polyglycerin, polyalkylene glycol, and fatty acid esters thereof.

  The degree of polymerization of polyglycerol is preferably 1 or more, more preferably 2 or more, preferably 20 or less, and preferably 10 or less. This is because if the degree of polymerization of polyglycerin is within the above range, the texture becomes good. The degree of polymerization of the polyalkylene glycol is preferably 1 or more, more preferably 2 or more, preferably 450 or less, and more preferably 400 or less. This is because if the degree of polymerization of the polyalkylene glycol is within the above range, the texture is good. The alkylene group constituting the polyalkylene glycol is preferably an alkylene group having 1 to 4 carbon atoms. Specific examples of the polyalkylene glycol include polymethylene glycol, polyethylene glycol, polypropylene glycol, and polybutylene glycol.

  Although it does not specifically limit as a fatty-acid component which comprises the fatty acid ester of polyglycerol and the fatty acid ester of polyalkylene glycol, A C1-C24 fatty acid can be mentioned. Examples of fatty acids having 1 to 24 carbon atoms include formic acid (C1), acetic acid (C2), propionic acid (C3), butyric acid (C4), valeric acid (C5), caproic acid (C6), and enanthic acid (C7). ), Caprylic acid (C8), pelargonic acid (C9), capric acid (C10), lauric acid (C12), myristic acid (C14), myristoleic acid (C14), pentadecylic acid (C15), palmitic acid (C16) , Palmitoleic acid (C16), margaric acid (C17), stearic acid (C18), elaidic acid (C18), vaccenic acid (C18), oleic acid (C18), linoleic acid (C18), linolenic acid (C18), 12 -Hydroxystearic acid (C18), arachidic acid (C20), gadoleic acid (C20), arachidonic acid (C20), eicosenoic acid (C 0), behenic acid (C22), erucic acid (C22), lignoceric acid (C24), and the like nervonic (C24).

  As the texture modifier, diethylene glycol, dipropylene glycol, acetic acid monoglyceride, acetic acid triglyceride, glycerin, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, Particularly preferred are propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monobutyl ether and the like. You may use the said texture modifier individually or in mixture of 2 or more types.

  The treatment amount of the texture modifier is preferably 0.05 parts by mass or more, more preferably 0.07 parts by mass or more, and preferably 5.00 parts by mass or less, based on 100 parts by mass of the untreated absorber. .8 parts by mass or less is more preferable. If the processing amount of a texture modifier is 0.05 mass part or more, the texture modification effect obtained will become high. If the amount of the texture modifier is more than 5.00 parts by mass, the effect of adding the texture modifier tends to be saturated. As an aspect of a process of a texture modifier, the aspect of spray-applying uniformly on the surface of an absorber is mentioned, for example.

  As will be described later, the absorbent body of the present invention can be formed into a thin shape by laminating a first sheet, an absorbent layer, and a second sheet and pressurizing them. For example, if a heat-adhesive synthetic fiber is contained in the absorbent layer, the first sheet, the absorbent layer, and the second sheet are firmly bonded by applying pressure under heating.

    The absorber of the present invention is thin. Although the thickness of the absorber of this invention is not specifically limited, 5 mm or less is preferable, 3 mm or less is more preferable, and 2 mm or less is further more preferable.

In the absorbent layer produced by the air array method of the absorbent body of the present invention, the basis weight of the water-absorbent resin powder is preferably 150 g / m ² or more, more preferably 200 g / m ² or more, and 400 g / m ^2. m ² or more is more preferable, 500 g / m ² or less is preferable, 480 g / m ² or less is more preferable, and 450 g / m ² or less is more preferable. When the basis weight is 150 g / m ² or more, the absorption amount by the absorption layer produced by the air array method is further improved. When the basis weight is 500 g / m ² or less, the texture of the absorbent body including the absorbent body produced by the air array method becomes better.

In the absorbent layer produced by the air array method of the absorbent body of the present invention, the basis weight of the raw cotton is preferably 15 g / m ² or more, more preferably 30 g / m ² or more, and 50 g / m ² or more. More preferably, it is 200 g / m ² or less, more preferably 100 g / m ² or less, and further preferably 70 g / m ² or less. If the basis weight is more than 200 g / m ² , the texture of the absorbent body including the absorbent body produced by the air array method becomes better.

The basis weight of the absorbent layer produced by the air array method possessed by the absorber of the present invention is preferably 165 g / m ² or more, more preferably 200 g / m ² or more, and 300 g / m ² or more. Is more preferably 700 g / m ² or less, more preferably 600 g / m ² or less, and even more preferably 500 g / m ² or less. This is because if the basis weight exceeds 700 g / m ² , it is difficult to reduce the thickness. If the basis weight is less than 165 g / m ² , it is difficult to secure the amount of absorption per unit area.

  Hereinafter, the manufacturing method of the absorber of this invention is demonstrated, referring drawings. Drawing 1 is an explanatory view showing an example of the device which manufactures the absorber of the present invention. An absorbent body manufacturing apparatus 100 according to the present invention includes a forming head 101 (101a, 101b, 101c) for mixing and discharging fibers supplied by carrier air, and a net for depositing the discharged fibers to form a web layer. A conveyor 103, a sunk 105 (105a, 105b, 105c) arranged below the net conveyor for sucking the conveying air, a heating device 107 for heating and bonding the fibers of the web layer if necessary, a roll 109 for pressing the web layer, And the winding roll 111 which winds up the obtained absorber is provided. The forming head 101 includes a rotor 113 for stirring the short fibers and a screen 115 provided with openings.

  The absorption layer used in the present invention is produced by an air array method, and is preferably produced, for example, as follows. The short fibers constituting the absorption layer are supplied from the fiber inlet 114 into the forming head 101 by a conveying air flow. The supplied short fibers are agitated by the rotor 113 and discharged from an opening provided in the screen 115. The discharged short fibers are sucked by the suction 105 disposed below the forming head 101 and collected on the net conveyor 103 to form a web layer. Water absorbent resin powder is sprayed from the water absorbent resin powder spray nozzle 116 on the obtained web layer. When producing the absorbent layer, the short fiber and the water-absorbent resin powder are supplied to the forming head, and a mixture thereof is discharged to absorb the short fiber and the water-absorbent resin powder (web layer). May be deposited on a net conveyor.

  Examples of the method for producing the absorbent body of the present invention include a method in which each of the first sheet, the absorbent layer, and the second sheet is produced by the air array method, and these are laminated and integrated. That is, a short fiber constituting a second sheet is discharged from the first forming head 101a, a second web layer is deposited on the net conveyor 103, and then a short fiber machine constituting an absorbent layer is formed from the second forming head 101b. By discharging, the web layer is deposited on the second web layer, and the water absorbent resin powder is sprayed from the water absorbent resin powder spray nozzle 116 to produce the absorbent layer. Further, the third forming head 101c The first web layer, the absorbent layer, and the second web layer are stacked by discharging the short fibers constituting one sheet and depositing the first web layer on the absorbent layer. The absorbent body is produced by pressing and integrating the obtained laminate (first web layer, absorbent layer, and second web layer) with a calender roll 109. If necessary, prior to pressurization by the calender roll 109, the laminated body may be heated by the heating device 107 to bond the heat-adhesive fibers constituting each web layer. The obtained absorbent is uniformly sprayed with the texture modifier from the texture modifier supply nozzle 118 and wound around the winding roll 111 as necessary.

  Moreover, when using a material with a specific gravity difference, it becomes easy to aim at uniform dispersion | distribution by adjusting the flow of air, or using the rotating apparatus for accustoming uniformly. As the airlaid nonwoven fabric manufacturing method, the Honshu paper manufacturing method (polymer, 17, No99 (1968)), the Cloyer method (Japanese Patent Publication No. Sho 54-6665), the Dunweb method (US 4,640,810), the J & J method, the Kimberly Clark method (Japanese Patent Publication No. 50-25045), Scott Paper Method (Pulp & Paper Week, 4, No. 6 (1983)) (see above, Basics and Applications of Nonwoven Fabrics (published by the Japan Society of Textile Technology, 1993)), opened Examples of the finer means include a rotating rotor (Honshu Paper Manufacturing Method), a rotating impeller (Croyer method), a reciprocating cylindrical screen and a needle roll (Danweb method, Japanese Patent Laid-Open No. 11-81116), and rotating. Serrated picker rotor (J & J method, Kimberly-Clark method, Scott paper method) I am using. By using this rotating device and adjusting the rotational speed, uniform dispersion can be achieved. In the figure (113: rotor) corresponds to this.

  In the embodiment of FIG. 1, the embodiment in which the texture modifier is sprayed after the pressure roll treatment is shown. However, the spray of the texture modifier is not limited to this embodiment, and is performed before the pressure roll treatment. Also good. Further, the texture modifier may be sprayed on either the first sheet or the second sheet, or may be sprayed on both. The absorber may have either the first sheet or the second sheet as an upper layer, but the texture modifier is preferably sprayed onto the first sheet, which is the sheet on the side in contact with the skin surface.

  As the pressure roll 109, a flat roll having a smooth surface may be used, or an embossing roll having an uneven surface may be used. By embossing the surface of the absorbent body, the first sheet, the absorbent layer, and the second sheet can be firmly adhered to each other, thereby preventing the water absorbent resin powder from being lost.

  In the case of calendering with a pressure roll, the pressure may be applied at any temperature from room temperature (non-heated) to high temperature if the thickness is simply adjusted. The pressure can be appropriately selected to obtain a desired thickness. The temperature of the roller surface is higher than the melting point of the low-melting component of the heat-adhesive conjugate fiber so as to reinforce the thermal bond between the fibers with a hot-pressure calender and improve strength, surface abrasion resistance, delamination prevention, etc. Is preferred. However, if the melting point is 30 ° C. or higher than the melting point of the low melting point component, or the melting point of the high melting point component (the core component of the core-sheath type composite fiber or the high melting point component of the side-by-side type composite fiber), the heat shrinkage of the fiber. Tends to be large, and sticking to the roller surface occurs, causing a problem in productivity. When the temperature of the roller surface is lower than the melting point of the low melting point component, reinforcement of the interfiber bond may not be sufficient. The heat treatment temperature for reinforcing the interfiber bond is preferably 110 ° C to 190 ° C, more preferably 120 ° C to 175 ° C.

  Moreover, if the linear pressure of the calendar process is set so as to be a uniform contact pressure in the width direction, an arbitrary pressure can be selected. Usually, the linear pressure of the calendar process can be arbitrarily selected in the range of 10 kgf / cm to 100 kgf / cm. The linear pressure is preferably a low pressure from the viewpoint of emphasizing flexibility.

  As the heat treatment performed by the heating device as necessary, for example, hot air treatment can be mentioned. The hot air treatment for forming the fiber-to-fiber bond requires a temperature equal to or higher than the melting point of the low-melting component of the thermoadhesive conjugate fiber. However, if the melting point is 30 ° C. or higher than the melting point of the low melting point component, or the melting point of the high melting point component (the core component of the core-sheath type composite fiber or the high melting point component of the side-by-side type composite fiber), the heat shrinkage of the fiber. Is likely to become large, and in a case where it is excessive, it causes deterioration of the fiber, which is not preferable. The hot air treatment temperature is usually preferably 110 ° C to 190 ° C, more preferably 120 ° C to 175 ° C.

  FIG. 2 is a mode in which the second sheet 117 and the first sheet 119 are introduced from the outside. The second sheet 117 fed from the roll 121 is conveyed onto the net conveyor 103 by the feed roll 123. On the 2nd sheet conveyed by the net conveyor, the short fiber which comprises an absorption layer is discharged from the forming head 101b, and the web layer which comprises an absorption layer is formed. Water absorbent resin powder is sprayed from the water absorbent resin powder spray nozzle 116 on the obtained web layer. Next, the first sheet 119 fed out from the roll 125 is stacked by the feed roll 127. The obtained laminate is pressed by a calender roll 109 to integrate the first sheet, the absorbent layer, and the second sheet to produce an absorbent body. If necessary, prior to pressurization by the calender roll 109, the laminated body may be heated by the heating device 107 to bond the heat-adhesive fibers constituting each web layer. A texture modifier is sprayed uniformly from the texture modifier supply nozzle 118 on the obtained absorbent body, and the absorbent body is wound around the winding roll 111.

  The configuration, arrangement, and the like of the absorber manufacturing apparatus of the present invention can be changed as appropriate.

  An absorbent article provided with the absorber of the present invention is included in the present invention. Specific examples of the absorbent article include absorbent articles that absorb a wearer's body fluid, such as disposable diapers, sanitary napkins, incontinence pads, and breast milk pads.

  Hereinafter, although the absorbent article of this invention is demonstrated referring drawings, this invention is not limited to the aspect shown by drawing.

  In FIG. 3, an example of the underpants type disposable diaper of this invention is shown (development figure). The pants-type disposable diaper 1 has a front part 3 and a back part 5 in the length direction A, and has a crotch part 7 between the front part 3 and the back part 5. The front abdomen 3 is in contact with the wearer's abdomen, and the back part 5 is in contact with the wearer's buttocks. The crotch portion 7 is provided with a notch 9 along the circumference of the wearer's leg. In the pants-type disposable diaper 1 of FIG. 3, the side edge 3a of the front abdominal part 3 and the side edge 5a of the back part 5 are joined, and it becomes the pants-type disposable diaper 1 which has a waist opening part and a pair of leg opening part.

  The pants-type disposable diaper 1 has an absorbent main body 13 attached to the skin surface side of the exterior sheet material 11. The absorbent main body 13 extends along the length direction A from the center of the crotch portion 7.

  A front waist elastic member 15 and a rear waist elastic member 17 are attached to the pant-type disposable diaper 1 along the edge 12 of the exterior sheet material 11 in a state of being stretched in the width direction B. Further, along the notch 9, the front leg elastic member 19 and the rear leg elastic member 21 are attached in an extended state. A state where the front waistline elastic member 23 and the back waistline elastic member 25 are extended in the width direction B between the waist elastic member and the leg elastic member in each of the front abdominal part 3 and the back back part 5. It is attached with. The disposable diaper 1 fits the wearer by contraction of each elastic member.

  FIG. 4 is a diagram schematically illustrating a cross section taken along line II of the pants-type disposable diaper of FIG. With reference to FIG. 4, the structure of the underpants type disposable diaper 1 is demonstrated. As shown in FIG. 4, the underpants type disposable diaper 1 of this invention has the exterior sheet | seat material 11 in the outer surface side of the absorptive main body 13 (or absorber 2). The exterior sheet material 11 includes an outer sheet 11a and an inner sheet 11b, and elastic members 15 and 17 for waist, elastic members 19 and 21 for legs, and elastic members 23 and 25 for waistline are stretched between the two sheets. It is attached with. The outer sheet 11a is longer in the length direction than the inner sheet 11b, and is folded back to the inner surface side (skin surface side) at the end edge 12 to form a folded portion 14. In FIG. 4, the right side in the C direction is the outer surface side, and the left side is the inner surface side (skin surface side).

  The absorbent main body 13 includes a top sheet 27 made of a nonwoven material disposed on the skin surface side of the absorbent body 2 and a liquid-impermeable back sheet 29 provided on the outer surface side of the absorbent body 2. In the pants-type disposable diaper 1, a front end press sheet 31 and a rear end press sheet 33 are provided so as to cover the lengthwise ends of the absorbent main body 13 at the front abdomen 3 and the back part 5 of the inner surface of the inner sheet 11 b. ing. The absorber 2 includes a first sheet 22, an absorption layer 26, and a second sheet 24. The absorption layer 26 contains the water-absorbent resin powder 6 and the short fibers 8, and is produced by the air lay method.

  FIG. 5 is a diagram schematically illustrating a cross section taken along the line II-II of the pant-type disposable diaper of FIG. 3. As shown in FIG. 5, a side sheet 35 made of a non-woven material is joined to the upper part of both side edges in the width direction of the top sheet 27 made of the non-woven material. The side seat 35 forms a rising flap that stands up toward the wearer's skin by the contraction force of the elastic member 37 attached in a stretched state in the length direction, and serves as a barrier that prevents lateral leakage of urine and the like. . In FIG. 5, the upper side in the C direction is the skin surface side, and the lower side is the outer surface side.

  Hereinafter, the present invention will be described in detail by way of examples. However, the present invention is not limited to the following examples, and all modifications and embodiments without departing from the gist of the present invention are not limited thereto. Included in range.

[Evaluation method]
(Measurement method of bulk density)
The bulk density is measured according to JIS K6219-2 2005. A water-absorbent resin powder as a sample is poured into a central portion of a cylindrical container having a known mass and volume (a stainless steel container having a diameter of 100 mm, a capacity of 1000 ml) from a height of 50 mm or less from the upper end of the container. At this time, a sufficient amount of sample is poured into the cylindrical container so that the poured sample forms a triangular pyramid above the upper end of the cylindrical container. Then, use a spatula to wipe off the excess sample above the upper end of the cylindrical container, measure the mass of the container in this state, and subtract the mass of the container from the measured value to obtain the mass of the sample. By dividing this by the volume of the container, the target bulk density is calculated. The measurement was performed 5 times (n = 5), the values at each of the upper and lower points were deleted, and the average value of the remaining three points was taken as the measured value. These measurements are performed at 23 ± 2 ° C. and a relative humidity of 50 ± 5%, and are measured after the sample is stored in the same environment for 24 hours or more before the measurement.

(Measurement method of water absorption rate by vortex method)
A 100 mL glass beaker with 50 mL of physiological saline (0.9 wt% sodium chloride water) and a magnetic stirrer chip (center diameter 8 mm, both ends diameter 7 mm, length 30 mm, surface coated with fluororesin ) And the beaker is placed on a magnetic stirrer (HPS-100 manufactured by ASONE). The rotational speed of the magnetic stirrer is adjusted to 600 ± 60 rpm, and the physiological saline is stirred. 2.0 g of the sample is put into the liquid at the center of the vortex of the saline solution being stirred, and the water absorption rate (seconds) of the water absorbent resin powder is measured according to JIS K 7224 (1996). Specifically, the stopwatch was started when the sample water-absorbent resin powder was completely charged into the beaker, and when the stirrer chip was covered with the test liquid (the vortex disappeared and the liquid surface became flat Stop the stopwatch at the time) and record the time (in seconds) as the water absorption rate. The measurement was performed 5 times (n = 5), the values at each of the upper and lower points were deleted, and the average value of the remaining three points was taken as the measured value. These measurements are performed at 23 ± 2 ° C. and a relative humidity of 50 ± 5%, and are measured after the sample is stored in the same environment for 24 hours or more before the measurement.

(Measurement method of liquid flow rate under load)
In a 100 mL glass beaker, 0.32 ± 0.005 g of the water-absorbent resin powder as a sample was immersed in 100 mL of physiological saline (0.9 wt% sodium chloride water) and allowed to stand for 60 minutes to swell. Separately, at the lower end of an opening of a vertically standing cylinder (inner diameter 25.4 mm), a wire mesh (mesh opening 150 μm, biocolumn sintered stainless steel filter 30SUS sold by Sansho Co., Ltd.) and a capillary (with an inner diameter of 2 mm) ( A filtration cylindrical tube having an inner diameter of 4 mm and a length of 8 cm) is prepared, and the contents of the beaker including the swollen measurement sample are put into the cylindrical tube with the cock closed. Next, a cylindrical rod having a diameter of 2 mm having a mesh opening of 150 μm and a diameter of 25 mm is inserted into the filtration cylindrical tube so that the mesh is in contact with the measurement sample. Place a weight so that a load is applied. After standing in this state for 1 minute, the cock is opened to flow the liquid, and the time until the liquid level in the filtration cylindrical tube reaches the 40 mL scale line from the 60 mL scale line (that is, 20 mL of liquid passes) (T ₁ ) (Seconds). Using the measured time T ₁ (seconds), the liquid flow rate under load at 2.0 kPa is calculated from the following equation. In the formula, T ₀ (seconds) is a value obtained by measuring the time required for 20 ml of physiological saline to pass through the wire mesh without putting the measurement sample in the filtering cylindrical tube.
Liquid passing speed under load (seconds) = (T ₁ −T ₀ )
The measurement was performed 5 times (n = 5), the values at each of the upper and lower points were deleted, and the average value of the remaining three points was taken as the measured value. These measurements are performed at 23 ± 2 ° C. and a relative humidity of 50 ± 5%, and are measured after the sample is stored for 24 hours or more in the same environment before the measurement.

(Hygroscopic blocking rate)
10.0 g of sample is uniformly placed in an aluminum cup (Toyo Echo Co., Ltd., foil container, product number 107) having a bottom diameter of 52 mm and a height of 22 mm, and kept in a constant temperature and humidity chamber at 40 ° C. and a relative humidity of 80% RH for 3 hours. Leave still. After that, it is lightly sieved with a 12-mesh wire mesh, measured by measuring the mass of the powdery material of the measurement sample that does not pass 12 mesh by blocking due to moisture absorption, and the weight measurement of the sample that passes 12 mesh. Calculate the rate.
Moisture absorption blocking rate (%) = (weight of sample not passing 12 mesh after standing) / (weight of sample not passing 12 mesh after standing + weight of sample passing 12 mesh after standing) × 100
The measurement was performed 5 times (n = 5), the values at each of the upper and lower points were deleted, and the average value of the remaining three points was taken as the measured value. The measurement is performed at 23 ± 2 ° C. and humidity 50 ± 5%, and the measurement is performed after storing the sample in the same environment for 24 hours or more before the measurement.

(Measurement method of absorption magnification)
The absorption magnification is measured according to JIS K 7223 (1996). Nylon mesh (JIS Z8801-1: 2000) with a mesh size of 63 μm is cut into a rectangle with a width of 10 cm and a length of 40 cm, folded in half at the center in the longitudinal direction, and both ends are heat sealed to a width of 10 cm (inner dimension: 9 cm), long A 20 cm long nylon bag is prepared. 1.00 g of a measurement sample is precisely weighed and placed uniformly in the bottom of the produced nylon bag. The nylon bag containing the sample is immersed in physiological saline. After 60 minutes from the start of immersion, the nylon bag is taken out from the physiological saline, suspended in a vertical state for 1 hour and drained, and then the mass (F1) of the sample is measured. Further, the same operation is performed without using a sample, and the mass F0 (g) at that time is measured. Then, from the masses F1 and F0 and the mass of the sample, a target absorption magnification is calculated according to the following formula.
Absorption capacity (g / g) = (F1-F0) / mass of sample

(Measurement method of water retention)
The water retention amount is measured according to JIS K 7223 (1996). Nylon mesh (JIS Z8801-1: 2000) with a mesh size of 63 μm is cut into a rectangle with a width of 10 cm and a length of 40 cm, folded in half at the center in the longitudinal direction, and both ends are heat sealed to a width of 10 cm (inner dimension: 9 cm), long A 20 cm long nylon bag is prepared. 1.00 g of a measurement sample is precisely weighed and placed uniformly in the bottom of the produced nylon bag. The nylon bag containing the sample is immersed in physiological saline. After 60 minutes from the start of soaking, the nylon bag is taken out from the physiological saline, suspended in a vertical state for 1 hour and drained, and then dehydrated using a centrifugal dehydrator (Kokusan Co., Ltd., model H-130C special model). The dehydrating condition is 143 G (800 rpm) for 2 minutes. The mass after dehydration (R1) is measured. Further, the same operation is performed without using a sample, and the mass R0 (g) at that time is measured. Then, from these masses R1, R0 and the mass of the sample, the target water retention amount is calculated according to the following equation.
Water retention amount (g / g) = (R1-R0-mass of sample) / mass of sample

<Surface dryness value by SDME method>
Prepared by immersing the absorbent in artificial urine (0.03% by weight potassium chloride, 0.08% by weight magnesium sulfate, 0.8% by weight sodium chloride and 99.09% by weight deionized water) and letting it stand for 60 minutes. Then, a sufficiently moistened absorbent body was produced. Moreover, the absorber was heat-dried at 80 degreeC for 2 hours, and the fully dried absorber was produced. A detector of an SDME (Surface Dryness Measurement Equipment) tester (manufactured by WK system) was placed on the sufficiently wetted absorber, and a 0% dryness value was set. Next, the SDME tester was calibrated by placing the detector of the SDME tester on the sufficiently dried absorber and setting the 100% dryness. Next, a metal ring (inner diameter 70 mm, length 50 mm) was set at the center of the absorber to be measured, 50 ml of artificial urine was injected, and the time until absorption of the artificial urine was measured to determine the absorption rate. Immediately after absorption, remove the metal ring, place one SDME detector in the center of the absorber, and start measuring the surface dryness value. After 3 minutes from the start of injection, the value after 5 minutes is the surface dryness value. Value. The artificial urine, measurement atmosphere, and standing atmosphere were 25 ± 5 ° C. and 65 ± 10% RH.

(Penetration rate)
Set a ring for measuring the penetration rate (inner diameter 50 mm, length 100 mm, weight 1250 g) at the center of the absorbent article to be measured, inject 50 ml of artificial urine, and measure the time from the start of injection until the completion of absorption of the artificial urine. The penetration rate was determined. After leaving for 30 minutes, the second artificial urine was injected, and after the 30th minute, the third artificial urine was injected. In addition, the fourth artificial urine injection was performed after 30 minutes, and the fourth penetration rate was determined. The artificial urine, measurement atmosphere, and standing atmosphere were 25 ± 5 ° C. and 65 ± 10% RH.

(Absorber texture)
A hand test of the absorber was performed by 50 adult women, and the evaluation was performed according to the following criteria. The average value of the obtained scores was shown.
Score (compared to standard product)
1 point: Hard 2 points: Equivalent 3 points: Slightly soft 4 points: Soft 5 points: Very soft

[Synthesis of water-absorbent resin powder (hereinafter, simply referred to as “SAP (Super Absorbent Polymer)”)]
<Synthesis Example 1>
Water-soluble ethylenically unsaturated monomer (a1-1) {acrylic acid, manufactured by Mitsubishi Chemical Corporation, purity 100%} 155 parts by mass (2.15 mol part), internal cross-linking agent (b1) {pentaerythritol triallyl ether, Made by Daiso Co., Ltd.} 0.6225 parts by mass (0.0024 mol part) and 340.27 parts by mass of deionized water were kept at 1 ° C. while stirring and mixing. After flowing nitrogen into this mixture to reduce the dissolved oxygen amount to 0.1 ppm or less, 0.31 part by mass of 1% aqueous hydrogen peroxide solution, 1.1625 parts by mass of 1% aqueous ascorbic acid solution, and 0.5% of 2 , 2′-Azobis [2-methyl-N- (2-hydroxyethyl) -propionamide] aqueous solution 2.325 parts by mass was added and mixed to initiate polymerization. After the temperature of the mixture reached 85 ° C., polymerization was carried out at 85 ± 2 ° C. for about 10 hours to obtain a hydrogel (1). Next, while adding 508.27 parts by mass of this hydrous gel (1) with a mincing machine (12VR-400K manufactured by ROYAL), 128.42 parts by mass of 48.5% aqueous sodium hydroxide solution was added and mixed, Further, 3 parts by mass of a 1% aqueous solution of ethylene glycol diglycidyl ether was added and mixed to obtain a chopped gel (2). Further, the chopped gel (2) was dried with a ventilation band dryer {200 ° C., wind speed 5 m / sec} to obtain a dried product. After the dried product was pulverized with a juicer mixer (Osterizer BLENDER manufactured by Oster), dried particles were obtained by adjusting the particle size to 150 μm to 710 μm using a sieve having openings of 150 μm and 710 μm. While stirring 100 parts by mass of the dry particles (high-speed stirring turbulizer manufactured by Hosokawa Micron: rotation speed 2000 rpm), a 2% water / methanol mixed solution of ethylene glycol diglycidyl ether (water / methanol weight ratio = 70/30). 5 parts by mass of () was added while being sprayed and mixed, and allowed to stand at 150 ° C. for 30 minutes for surface crosslinking to obtain (A) a crosslinked polymer. With respect to 100 parts by mass of this (A) cross-linked polymer, (B) 0.5 part by mass of silica (Aerosil 380 manufactured by Toshin Kasei Co., Ltd.) as a surface modifier and carboxy-modified polysiloxane (Shin-Etsu Chemical Co., Ltd.) The product was stirred at 85 ° C. for 60 minutes using 0.02 part by mass of X-22-23701E). The weight average particle diameter of the obtained resin powder was adjusted to 400 μm, and water absorbent resin powder 1 was obtained.

<Synthesis Example 2>
“Drying the shredded gel (2) with a ventilation band dryer {200 ° C., wind speed 5 m / sec}” “Drying the shredded gel (2) with a ventilation band dryer {150 ° C., wind speed 5 m / sec} A water-absorbent resin powder 2 was obtained in the same manner as in Synthesis Example 1 except that it was changed to "".

<Synthesis Example 3>
“Drying the chopped gel (2) with a ventilation band dryer {200 ° C., wind speed 5 m / sec}” “Drying the chopped gel (2) with a ventilation band dryer {150 ° C., wind speed 2 m / sec}” A water-absorbent resin powder 3 was obtained in the same manner as in Synthesis Example 1 except that the above was changed.

<Synthesis Example 4>
A water-absorbent resin powder 4 was obtained in the same manner as in Synthesis Example 3, except that “Adjusting the weight average particle diameter to 400 μm” was changed to “Adjusting the weight average particle diameter to 530 μm”.

<Synthesis Example 5>
A water-absorbent resin powder 5 was obtained in the same manner as in Synthesis Example 2, except that “Adjust weight-average particle diameter to 400 μm” was changed to “Adjust weight-average particle diameter to 320 μm”.

<Synthesis Example 6>
A water-absorbent resin powder 6 was obtained in the same manner as in Synthesis Example 1 except that “Adjusting the weight average particle diameter to 400 μm” was changed to “Adjusting the weight average particle diameter to 280 μm”.

<Synthesis Example 7>
“(B) 0.5 parts by mass of silica (Aerosil 380 manufactured by Toshin Kasei Co., Ltd.) and 0.02 parts by mass of carboxy-modified polysiloxane (X-22-3701E manufactured by Shin-Etsu Chemical Co., Ltd.) as surface modifiers ”Was changed to“ (B) 0.5 part by mass of silica (Aerosil 380 manufactured by Toshin Kasei Co., Ltd.) as a surface modifier ”, to obtain a water-absorbent resin powder 7 in the same manner as in Synthesis Example 2. .

<Synthesis Example 8>
“(B) 0.5 parts by mass of silica (Aerosil 380 manufactured by Toshin Kasei Co., Ltd.) and 0.02 parts by mass of carboxy-modified polysiloxane (X-22-3701E manufactured by Shin-Etsu Chemical Co., Ltd.) as surface modifiers ”Was changed to“ (B) 0.5 part by mass of silica (Aerosil 200 manufactured by Toshin Kasei Co., Ltd.) as a surface modifier ”, to obtain water-absorbent resin powder 8 in the same manner as in Synthesis Example 2. .

<Synthesis Example 9>
“(B) 0.5 parts by mass of silica (Aerosil 380 manufactured by Toshin Kasei Co., Ltd.) and 0.02 parts by mass of carboxy-modified polysiloxane (X-22-3701E manufactured by Shin-Etsu Chemical Co., Ltd.) as surface modifiers In the same manner as in Synthesis Example 2, except that “(B) 0.02 parts by mass of carboxy-modified polysiloxane (X-22-3701E manufactured by Shin-Etsu Chemical Co., Ltd.) as a surface modifier” was changed. Resin powder 9 was obtained.

<Synthesis Example 10>
“(B) 0.5 parts by mass of silica (Aerosil 380 manufactured by Toshin Kasei Co., Ltd.) and 0.02 parts by mass of carboxy-modified polysiloxane (X-22-3701E manufactured by Shin-Etsu Chemical Co., Ltd.) as surface modifiers "" (B) Amino-modified polysiloxane (Shin-Etsu Chemical Co., Ltd. KF-880) 0.02 parts by mass as surface modifier ") 10 was obtained.

<Comparative Synthesis Example 1>
“Drying the chopped gel (2) with a ventilation band dryer {200 ° C., wind speed 5 m / sec}” “Drying the chopped gel (2) with a ventilation band dryer {120 ° C., wind speed 2 m / sec}” Comparative water absorbent resin powder 1 was obtained in the same manner as in Synthesis Example 1 except that

<Comparative Synthesis Example 2>
Comparative water-absorbent resin powder 2 was obtained in the same manner as in Synthesis Example 1 except that “Adjusting the weight average particle diameter to 400 μm” was changed to “Adjusting the weight average particle diameter to 600 μm”.

<Comparative Synthesis Example 3>
Comparative water-absorbent resin powder 3 was obtained in the same manner as in Synthesis Example 2, except that “Adjust weight average particle diameter to 400 μm” was changed to “Adjust weight average particle diameter to 280 μm”.

<Comparative Synthesis Example 4>
2 parts of polyethylene glycol (PEG 200 manufactured by Sanyo Chemical Industries) was added to 100 parts by weight of the water absorbent resin powder 7 and stirred at 85 ° C. for 60 minutes. The weight average particle diameter of the obtained resin powder was adjusted to 400 μm to obtain a comparative water absorbent resin powder 4.
<Comparative Synthesis Example 5>
As the water absorbent resin powder, Aqua Keep SA60SXII manufactured by Sumitomo Seika Co., Ltd. was used.

  Table 1 shows the measured physical properties of the water absorbent resin powders obtained in Synthesis Examples 1 to 10 and Comparative Synthesis Examples 1 to 5.

[Production of absorber]
[Example absorber 1]
As the first sheet, air-through unemployed cloth (LD18 manufactured by Venus Paper Co., Ltd.) was used. PET / PE raw cotton (manufactured by Teijin) was defibrated, and the obtained short fibers were deposited on the first sheet by the air array method to form a web layer. A web layer in which the water-absorbent resin powder 1 is spread on the obtained web layer, and further PET / PE raw cotton (manufactured by Teijin) is defibrated and the obtained short fibers are deposited by the airlaid method. Example absorber in which an air-through nonwoven fabric (LD18 manufactured by Venus Paper Co., Ltd.) is laminated as a second sheet after lamination and treated with a pressure roll having a surface temperature of 150 ° C., and an absorbent layer is formed by an airlaid method 1 was obtained.

[Example absorbers 2 to 10]
Example absorbers 2 to 10 were obtained in the same manner as Example absorber 1 except that “water absorbent resin powder 1” was changed to “water absorbent resin powder 2 to 10”.

[Example absorber 11, 12]
Example absorbers 11 and 12 were produced in the same manner as Example absorber 2 except that the raw cotton basis weight was changed to 30 g / m ² .

[Example absorber 13, 14]
Example absorbers 13 and 14 were produced in the same manner as Example absorber 2 except that the SAP basis weight was changed to 400 g / m ² .

[Example absorber 15]
As the first sheet, air-through unemployed cloth (LD18 manufactured by Venus Paper Co., Ltd.) was used. PET / PE raw cotton (manufactured by Teijin) was defibrated, the defibrated short fibers and the water absorbent resin powder 1 were mixed, and the obtained mixture was deposited on the first sheet by the air lay method to form a web layer. . On the obtained web layer, an air-through nonwoven fabric (LD18 manufactured by Venus Paper Co., Ltd.) was laminated as a second sheet and heat treated with a pressure roll having a surface temperature of 150 ° C., and the absorbent layer was produced by the airlaid method. Example absorber 15 was obtained.

[Example absorber 16]
Example absorber 16 was obtained in the same manner as Example absorber 1 except that diethylene glycol was uniformly sprayed on the first sheet side of example absorber 1.

[Example absorbers 17 to 21]
Example absorbers 17 to 21 were produced in the same manner as the example absorber 16 except that the formulation of the texture modifier shown in Table 3 was changed.

[Comparative Example Absorber 1]
Comparative Example Absorber 1 was obtained in the same manner as Absorber 1, except that “Water Absorbent Resin Powder 1” was changed to “Comparative Water Absorbent Resin Powder 1”.

[Comparative Example Absorbers 2 to 4]
The same as Comparative Example Absorbent 1 except that “Comparative water absorbent resin powder 1” was changed to “Comparative water absorbent resin powder 2-4”. Comparative example absorbers 2 to 4 were obtained.

[Comparative Example Absorbers 5, 6]
Comparative Example absorbent bodies 5 and 6 were produced in the same manner as Comparative Example absorbent body 2 except that the raw cotton basis weight was changed to 30 g / m ² .

[Comparative Absorber 7]
The same as Comparative Example Absorbent 1 except that “Comparative Water Absorbent Resin Powder 1” was changed to “Comparative Water Absorbent Resin Powder 5”. A comparative absorbent body 7 was obtained.

  About the obtained absorber, SAP basis weight, SAP content rate, and raw cotton basis weight in the absorption layer produced by the air array method are shown together in Table 2. Moreover, in order to evaluate the permeability to the obtained absorber, the time (absorption rate) until the artificial urine was completely absorbed was measured. Moreover, in order to evaluate the reversibility of an absorber, the surface dryness value by SDME method was measured. These results are shown in Table 2.

  As can be seen from Table 2, the example absorbent bodies 1 to 15 of the present invention show an excellent penetration rate and dryness as compared with the comparative absorbent bodies 1 to 7. This is considered to be due to the improvement of the permeability to the absorber and the absorption by containing the water-absorbing resin powder having specific physical properties. On the other hand, Comparative Example absorbers 1 to 7 show inferior results compared to the absorber of the present invention.

  Since the comparative example absorber 1 has a large bulk density of the water-absorbent resin powder contained therein, the permeability to the absorber is difficult to be improved. Therefore, it is estimated that the penetration rate was inferior. Since the comparative example absorber 2 has a low absorption rate of the water-absorbing resin powder contained therein, the permeability to the absorber and the dryness are hardly improved. Therefore, it is estimated that the penetration rate and surface dryness were inferior. Since the comparative example absorber 3 has a slow absorption rate under load of the water-absorbent resin powder contained therein, the permeability to the absorber and the dryness are hardly improved. Therefore, it is estimated that the penetration rate and surface dryness were inferior. Since the comparative example absorbent body 4 has a high moisture absorption blocking rate of the water-absorbent resin powder contained therein, the permeability to the absorbent body and the dryness are hardly improved. Therefore, it is estimated that the penetration rate and surface dryness were inferior. Since the comparative example absorber 5 has a small content of the water-absorbing resin powder contained therein, it is difficult to improve the dryness of the absorber. Therefore, the surface dryness value was inferior. The comparative absorbent body 6 could not be formed into a sheet because the content of the water-absorbent resin powder was too high.

  From the results of Table 3, it can be seen that each of the example absorbent bodies 16 to 21 treated with the texture modifier is soft and textured.

  ADVANTAGE OF THE INVENTION According to this invention, an absorption body with high absorption performance, a thin shape, and a favorable feel is obtained. The absorbent body of the present invention is useful for absorbent articles such as incontinence pads, disposable diapers, sanitary napkins, and breast milk pads.

1: Disposable diaper (absorbent article) 2: Absorbent body 3: Front abdomen 4: Hydrophobic adsorbent 5: Back part 6: Water-absorbent resin powder satisfying the requirements of (a) to (d) , 7: crotch portion, 8: fiber base material, 9: notch, 11: exterior sheet material, 12: edge, 13: water-absorbing main body, 15: elastic member for front waist, 17: elastic member for rear waist , 19: front leg elastic member, 21: rear leg elastic member, 22: first sheet, 23: front waist elastic member, 24: second seat, 25: rear waist elastic member, 26 : Absorbing layer, 27: Liquid-permeable top sheet, 29: Liquid-impervious back sheet, 31: Front end pressing sheet, 33: Rear end pressing sheet, 34: Joining part, 35: Side sheet, 37: Elastic member 100: Absorber manufacturing apparatus, 101: Forming head, 103: Ne 105: Sanction, 107: Heating device, 109: Pressure roll, 111: Winding roll, 113: Rotor, 115: Screen, 116: Water-absorbing resin powder spray nozzle, 117: Second sheet, 118: Texture modification Agent spray nozzle, 119: first sheet, 121: roll, 123: feed roll, 125: roll, 127: feed roll, 129: transport roll

Claims (12)

It is an absorbent body that includes a water-absorbing resin powder that satisfies the following requirements (a) to (d), and that has an absorbent layer prepared by an air array method, wherein the mass ratio of the water-absorbent resin powder is the absorbent layer 65.0 mass% or more and 95.2 mass% or less with respect to the total mass of the absorber.
(A) Bulk density: 0.45 g / ml to 0.62 g / ml
(B) Absorption speed by vortex method: 20 seconds to 50 seconds (c) Liquid passing speed under load: 10 seconds or less (d) Hygroscopic blocking ratio: 5% or less   The absorption body according to claim 1, wherein the absorption capacity of the water-absorbent resin powder is 40 g / g to 55 g / g.   The absorbent body according to claim 1 or 2, wherein a water retention amount of the water absorbent resin powder is 20 g / g to 45 g / g.   The water-absorbent resin powder comprises (a1) a water-soluble ethylenically unsaturated monomer and / or (a1) a water-soluble ethylenic monomer produced by hydrolysis, (a2) a hydrolyzable monomer, (b) an internal crosslinking agent, The polymer (A) obtained by polymerizing a monomer composition containing a polymer is obtained by treating with (B) a surface modifier. Absorber.   The absorbent according to claim 4, wherein the treatment amount of the (B) surface modifier is 0.001 to 1 part by mass with respect to 100 parts by mass of the (A) crosslinked polymer.   6. The absorbent according to claim 4 or 5, wherein the (B) surface modifier is at least one selected from the group consisting of amino-modified polysiloxane, carboxy-modified polysiloxane, and silica.   It has a liquid-permeable 1st sheet | seat and a 2nd sheet | seat, The said absorption layer is arrange | positioned between the said 1st sheet | seat and a 2nd sheet | seat. Absorber. The basis weight of the water-absorbent resin powder absorption ^layer, the absorption body according to any one of claims 1 to 7 is a ^{150g / m 2 ~500g / m 2} .   The thickness of the said absorber is 0.5 mm-5 mm, The absorber as described in any one of Claims 1-8.   The texture modifier is treated with polyglycerol having a polymerization degree of 1 to 10 or a fatty acid ester thereof, or polyalkylene glycol having a polymerization degree of 1 to 20 or a fatty acid ester thereof. The absorber of description.   The absorber according to claim 10, wherein the texture modifier is treated in an amount of 0.05 to 5.00 parts by mass with respect to 100 parts by mass of the untreated absorber. An absorbent article provided with the absorber as described in any one of Claims 1-11.

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