JP6868964B2 - Absorbent article - Google Patents

Description

The present invention relates to an absorbent article.

Conventionally, an absorbent article having a top sheet, a back sheet, and an absorber arranged between them, and a second sheet arranged between the top sheet and the absorber is known. The second sheet is provided to enhance the absorption performance of body fluids such as urine of absorbable articles. Absorbent articles in which such a second sheet is arranged are described in, for example, Patent Documents 1 to 3.

In Patent Document 1, an average cell diameter of at least 100 μm is provided between the top sheet and the back sheet, and (a) a pushing force deflection of less than 75 N at 50%, or (b) 25% at 50% deflection. An absorbent article is described in which an absorbent composite comprising a first absorbent layer containing a polymer foam having at least one property selected from less than constant deflection compression set is arranged (Patent Document 1 (Claim)). Item 1, paragraphs 0018, 0034, FIG. 1)). Patent Document 2 describes a fourth member of 75 ml at 15 ml / sec in an absorption structure including a first member for liquid capture / liquid distribution and a second member for final storage of the captured liquid by a liquid dropping test. An absorber having an absorption structure having a liquid dropping ratio of less than 50% with respect to torrent is described (see Patent Document 2 (Claim 11, 0030, 0035-0037)). Patent Document 3 has a top sheet, a back sheet, and an absorbent core contained between them. The absorbent core includes a base material layer and an absorbent polymer material layer, and the base material layer is foamed. An absorbent article comprising a material layer is described (see Patent Document 3 (Claims 4, 11, paragraph 0035, FIG. 3)).

It has also been proposed that a solid-liquid separation / absorber sheet be placed on the absorbent article for the purpose of treating loose stools. As such a solid-liquid separation / absorber sheet, for example, Patent Document 4 includes ^{a polyurethane open cell foam having a density of 100 to 200 kg / m 3} and a thickness of 0.5 to 3.0 mmt. A solid-liquid separation sheet has been proposed (see Patent Document 4 (Claim 1)).

Japanese Patent Application Laid-Open No. 2015-521079 Special Table 2003-515357 Gazette Special Table 2012-51930 Japanese Unexamined Patent Publication No. 2015-80580

An object of the present invention is to provide an absorbent article having an excellent absorption rate of body fluid.

The absorbent articles of the present invention that could solve the above problems include a liquid-permeable top sheet, a second sheet arranged on the outer surface side of the top sheet, and an absorbent article arranged on the outer surface side of the second sheet. It has a body and an impermeable back sheet arranged on the outer surface side of the absorber, and the second sheet is made of a polyurethane continuous porous body and has an apparent density of 100 kg / m ^{3 to} 200 kg / m ^3. It is characterized by being.

The absorbent article of the present invention has an excellent absorption rate of body fluid.

It is a top view which shows an example of the absorbent article of this invention. It is a schematic cross-sectional view of the VV line of FIG. It is a top view which shows the arrangement mode of the adhesive of the absorbent article of FIG. It is a top view which shows another example of the absorbent article of this invention. It is a schematic cross-sectional view of the VV line of FIG. It is a top view which shows another example of the absorbent article of this invention. FIG. 6 is a schematic cross-sectional view taken along the line VV of FIG. It is a top view which shows the arrangement mode of the adhesive of the absorbent article of FIG. It is a top view which shows another example of the absorbent article of this invention. It is a schematic cross-sectional view of the VV line of FIG.

The absorbent article of the present invention includes a liquid-permeable top sheet, a second sheet arranged on the outer surface side of the top sheet, an absorber arranged on the outer surface side of the second sheet, and an outer surface side of the absorber. and a back sheet arranged liquid-impermeable in the second sheet is made of polyurethane continuous porous body, the apparent density is characterized by a ^{100kg / m 3 ~200kg / m 3} .

1 Second sheet The second sheet is made of a polyurethane continuous porous body, has an apparent density of 100 kg / m ^{3 to} 200 kg / m ³ , and has an excellent water permeability. Therefore, in the absorbent article of the present invention, the body fluid excreted on the top sheet is immediately taken into the second sheet. In addition, the body fluid taken into the second sheet quickly permeates in the thickness direction, reaches the absorber from the second sheet, and is absorbed and retained by the absorber. Therefore, the absorbent article of the present invention has a high absorption rate of body fluid.

1.1 Physical properties The apparent density of the second sheet is 100 kg / m ³ or more, preferably 120 kg / m ³ or more, more preferably 130 kg / m ³ or more, 200 kg / m ³ or less, preferably 180 kg / m ³ or less. , More preferably 170 kg / m ³ or less. When the apparent density of the second sheet is 100 kg / m ³ or more, the water permeation rate is good, and when it is 200 kg / m ³ or less, the permeation amount is good. The apparent density is the mass per unit volume of a sample that includes both breathable and non-breathable pores. The apparent density of the second sheet is calculated by measuring the volume and mass of a test piece ^{having a volume of 100 cm 3 or more.}

The thickness of the second sheet is preferably 0.5 mm or more, more preferably 1.0 mm or more, further preferably 1.5 mm or more, preferably 4.0 mm or less, more preferably 3.0 mm or less, still more preferable. Is 2.5 mm or less. If the thickness of the second sheet is 0.5 mm or more, the mechanical strength of the second sheet is good, and if it is 4.0 mm or less, the water permeability of the second sheet is good. The thickness of the second sheet is measured using a digital caliper.

The water permeation rate of the second sheet is preferably 0.125 mL / sec or more, more preferably 0.20 mL / sec or more, still more preferably 0.25 mL / sec or more. When the water permeation rate is 0.125 ml / sec or more, the body fluid rapidly diffuses in the thickness direction in the second sheet, so that the absorption rate of the absorbent article is further improved.

1.2 Polyurethane continuous porous body The second sheet is composed of a polyurethane continuous porous body. The porous body has a large number of pores. Further, in the continuous porous body, a large number of pores are breathable. In a continuous porous body, each pore has a through hole with the surface of the porous body, or has a through hole between adjacent pores. The shape of each pore is not particularly limited. Further, the polyurethane continuous porous body may have non-breathable pores.

In the polyurethane continuous porous body, the number of pores (number of cells) is preferably 15 cells / 25 mm width, more preferably 20 cells / 25 mm width or more, preferably 70 cells / 25 mm width or less, more preferably. 60 pieces / 25 mm width or less. When the number of cells is 15/25 mm width or more, the water permeation speed is good. The number of cells is measured based on the annex of JIS K6400-1 (2004). Specifically, for a test piece of a polyurethane continuous porous body (thickness 10 mm or more, width and length 100 mm or more), using a magnifying glass (magnification 5 times or more), cells between 10 mm on a straight line at three locations Count the number and calculate the average value.

The air permeability of the polyurethane continuous porous body is preferably 10 L / min or more, more preferably 20 L / min or more, preferably 120 L / min or less, and more preferably 100 L / min or less. If the air permeability of the second sheet is 10 L / min or more, stuffiness inside the absorbent article can be prevented. The air permeability of the polyurethane continuous porous body is measured according to ASTM D3574.

The polyurethane continuous porous body is not particularly limited, and examples thereof include those produced by a foaming method, those produced by an extraction method, and those produced by a W / O emulsion method. Further, the polyurethane continuous porous body is preferably one that has been subjected to a heat compression treatment in the thickness direction. By the heat compression treatment, each skeleton forming the pore structure in the continuous porous body is compressed and deformed in the compression direction, and is deformed as if folded. As a result, the continuously porous body after the heat compression molding has a denser cell space in the compression direction and a state in which the cell skeletons are lined up in the horizontal direction as compared with the state before the heat compression molding. Therefore, the water permeability in the thickness direction is further improved, and the diffusivity in the horizontal direction is also excellent.

The polyurethane continuous porous body preferably has a hydrophilic skeleton surface. If the skeletal surface is hydrophilic, the rate of taking body fluid into the second sheet is further increased, and the absorption rate of the absorbent article is further improved.

Whether or not the skeleton surface is hydrophilic is determined by the following method. First, a polyurethane continuous porous body (width 10 mm or more, length 10 mm or more) is placed on the edge of the petri dish. At this time, the polyurethane continuous porous body should not be bent. Next, using a dropper, 10 droplets (0.05 ml) are gently placed on the polyurethane continuous porous body, and the time until these droplets are absorbed by the polyurethane continuous porous body is measured. Then, when 8 or more droplets are absorbed within 5 seconds after the droplets are placed, it is judged to be hydrophilic. For the droplets, ion-exchanged water (surface tension (Wilhelmy method, platinum plate, 20 ° C., 65% RH): 70 mN / m or more) is used.

Examples of the polyurethane continuous porous body having a hydrophilic surface on the skeleton include those in which the polyurethane itself constituting the skeleton has hydrophilicity; and those obtained by hydrophilizing a hydrophobic polyurethane continuous porous body. Examples of the polyurethane itself constituting the skeleton having hydrophilicity include those containing a polyalkylene oxide polyol as a polyol component. Hydrophobic polyurethane continuous porous materials that have been hydrophilized include those in which at least a part of the skeleton surface of the hydrophobic polyurethane continuous porous material is coated with a surfactant, and hydrophobic polyurethane continuous porous materials. Examples thereof include those obtained by treating the body with a reactive gas such as ethylene oxide to impart a hydrophilic group to the surface of the pores.

Examples of the surfactant include anionic surfactants, cationic surfactants, amphoteric surfactants, and nonionic surfactants. Examples of the anionic surfactant include carboxylates, sulfonates, sulfates and the like. Examples of the nonionic surfactant include an ester-type nonionic surfactant, an ether-type nonionic surfactant, and an ester-ether-type nonionic surfactant.

1.2.1 Polyurethane The polyurethane constituting the polyurethane continuous porous body is a product in which urethane bonds are formed in the molecular weight by reacting a polyol component with a polyisocyanate component, and if necessary, Further, it is obtained by carrying out a chain extension reaction with a chain extender such as a low molecular weight polyol or a low molecular weight polyamine.

1.2.1.1 Polyol component The polyol component is not particularly limited as long as it is used in the production of polyurethane and has two or more hydroxyl groups in the molecule. Examples of the polyol component include polyether polyols, polyester polyols, polycarbonate polyols, polylactone polyols, polyolefin polyols, silicone-based polyols, acrylic-based polyols, castor oil-based polyols, and the like. These polyol components may be used alone or in combination of two or more.

Examples of the polyether polyol include a polyether polyol obtained by polymerizing or copolymerizing an alkylene oxide and / or a heterocyclic ether, an amine-based ether polyol obtained by adding an alkylene oxide to an amine compound, and the like. Examples of the alkylene oxide include ethylene oxide, propylene oxide and butylene oxide. Examples of the heterocyclic ether include tetrahydrofuran and the like. Examples of the amine compound include mono or diamine, hydrazine, substituted hydrazine and the like. Specific examples of the polyether polyol include polyethylene glycol, polypropylene glycol, polyethylene-polypropylene glycol, polyethylene-tetramethylene glycol, polytetramethylene glycol, poly-2-methyltetramethylene glycol, polyhexamethylene glycol and the like.

Examples of the polyester polyol include those obtained by polycondensing an aliphatic dicarboxylic acid and / or an aromatic dicarboxylic acid and a low molecular weight glycol. Examples of the aliphatic dicarboxylic acid include succinic acid, adipic acid, sebatic acid, glutaric acid, azelaic acid and the like. Examples of the aromatic dicarboxylic acid include orthophthalic acid, isophthalic acid, terephthalic acid, 1,5-naphthalenedicarboxylic acid and the like. Examples of the low molecular weight glycol include ethylene glycol, propylene glycol, 1,3-propanediol, 1,4-butanediol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, neopentyl glycol, and diethylene glycol. , Pentaerythritol, 1,4-dihydroxymethylcyclohexane and the like. Specific examples of the polyester polyol include polyethylene glycol adipate, polybutanediol adipate, polyhexanediol adipate, poly-3-methylpentanediol adipate, polyneopentyl glycol adipate, polyethylene / butylene adipatediol, polyneopentyl / hexyl adipate. Examples thereof include diols and polybutylene isophthalate diols.

Examples of the polycarbonate polyol include polybutanediol carbonate, poly-3-methylpentanediol carbonate, polyhexanediol carbonate, polynonanediol carbonate, polybutanediol hexanediol carbonate, polypentanediol hexanediol carbonate, and poly-2-methyloctane. Examples thereof include diol nonane diol carbonate and poly-3-methylpentanediol hexanediol carbonate.

Examples of the polylactone polyol include polycaprolactone diol, polycaprolactone triol, poly-3-methylvalerolactone diol and the like.

Examples of the polyolefin polyol include polybutadiene glycol, polyisoprene glycol, and hydrides thereof.

The silicone-based polyol is a polysiloxane main chain in which a hydroxyl group is introduced. Further, the introduced hydroxyl group may be at both ends or one end of the polysiloxane main chain.

The polyol component preferably contains a compound that can impart hydrophilicity to polyurethane. Specifically, an embodiment in which the polyol component contains a polyalkylene oxide polyol; an embodiment in which the polyol component contains an acidic group-containing polyol; is preferable. The polyalkylene oxide polyol is obtained by adding an alkylene oxide containing an ethylene oxide structure to at least one compound selected from a polyhydric alcohol, a polyhydric phenol and an amine compound.

Examples of the polyhydric alcohol include dihydric alcohols, trihydric alcohols, and tetrahydric or higher polyhydric alcohols. Examples of the dihydric alcohol include alkylene glycols such as ethylene glycol, propylene glycol, butanediol, hexanediol and neopentyl glycol; and cycloalkylene glycols such as cyclohexanediol and cyclohexanedimethanol. Examples of the trihydric alcohol include alkanetriols such as glycerin, trimethylolpropane, trimethylolethane, and hexanetriol. Examples of the tetrahydric or higher polyhydric alcohol include alkane polyols such as pentaerythritol, sorbitol, mannitol, sorbitan, diglycerin, and dipentaerythritol. Examples of the polyhydric phenol include monocyclic polyhydric phenols such as pyroganol and hydroquinone; bisphenols such as bisphenol A, bisphenol F and bisphenol sulfone; and condensates (novolac) of phenol and formaldehyde. Examples of the amine compound include monoalkanolamines such as monoethanolamine, isopropanolamine and aminoethylethanolamine; polyalkanolamines such as diethanolamine, ethanolisopropanolamine and diisopropanolamine, monoamine compounds such as n-butylamine and octylamine; ethylenediamine. Diamine compounds such as propylenediamine and hexamethylenediamine; polyalkylene polyamines such as diethylenetriamine and triethylenetetramine; aromatic amine compounds such as aniline and phenylenediamine; alicyclic amine compounds such as isophoronediamine and cyclohexylenediamine; piperazine, Examples thereof include heterocyclic amine compounds such as aminoethyl piperazine.

As the polyalkylene oxide polyol, polyoxyethylene polyoxypropylene glycol is preferable. The polyalkylene oxide polyol preferably has a content of a unit derived from ethylene oxide in the polyalkylene oxide moiety of 40 mol% to 85 mol%. As the polyalkylene oxide polyol, it is also preferable to use a polyalkylene oxide diol having two hydroxyl groups in one molecule and a polyalkylene oxide triol having three hydroxyl groups in one molecule in combination.

Examples of the acidic group-containing polyol include those containing two or more hydroxyl groups and one or more acidic groups in one molecule. Examples of the acidic group include a carboxy group, a sulfonic acid group, a phosphoric acid group, and a phenolic hydroxyl group. The acidic group-containing polyol preferably has two hydroxyl groups and one carboxy group in one molecule.

Examples of the acidic group-containing polyol include dimethylol alkanoic acids such as 2,2-dimethylol propionic acid and 2,2-dimethylol butanoic acid; N, N-bishydroxyethylglycine, N, N-bishydroxyethylalanine, and the like. Examples thereof include 3,4-dihydroxybutanesulfonic acid and 3,6-dihydroxy-2-toluenesulfonic acid.

1.2.1.2 Polyisocyanate component The polyisocyanate component is not particularly limited as long as it is used in the production of polyurethane and has two or more isocyanate groups at the ends. Examples of the polyisocyanate component include aromatic polyisocyanates, hydrogenated aromatic polyisocyanates, alicyclic polyisocyanates, and aliphatic polyisocyanates. The polyisocyanate component also includes a dimer of diisocyanate, a trimer, and the like. Examples of the diisocyanate trimer include an isocyanurate form, a burette form, and an allophanate form. These polyisocyanate components may be used alone or in combination of two or more.

Examples of the aromatic polyisocyanate include 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, 4,4'-diphenylmethane diisocyanate, 3,3'-dichloro-4,4'-diphenylmethane diisocyanate, and 2,2'-. Examples thereof include diphenylmethane diisocyanate, 2,4'-diphenylmethane diisocyanate, xylylene diisocyanate, phenylene diisocyanate, and 1,5-naphthalenedi isocyanate. Examples of the hydrogenated additive of the aromatic polyisocyanate include hydrogenated diphenylmethane diisocyanate and hydrogenated xylylene diisocyanate. Examples of the alicyclic polyisocyanate include 1,4-cyclohexanediisocyanate, isophorone diisocyanate, norbornane diisocyanate and the like. Examples of the aliphatic polyisocyanate include tetramethylene diisocyanate, 1,6-hexamethylene diisocyanate, dimerate diisocyanate, and lysine diisocyanate.

1.2.1.3 Chain extender Examples of the low molecular weight polyol used as the chain extender include ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, 1,3-propanediol, and 1,4-butanediol. , 1,5-Pentanediol, 1,6-hexanediol, neopentyl glycol, 3-methylpentanediol, nonanediol, octanediol, dimethylolheptan, 1,4-cyclohexanediol and the like.

Examples of the low molecular weight polyamine used as the chain extender include aliphatic amines, alicyclic amines, and aromatic amines. Examples of the aliphatic amine include ethylenediamine, propylenediamine, butylenediamine, hexamethylenediamine, and triethylenetetramine. Examples of the alicyclic amine include 1,3-bis (aminomethyl) cyclohexane, 1,4-cyclohexanediamine, 3-aminomethyl-3,5-trimethylcyclohexylamine, isophoronediamine, piperazine, 2-methylpiperazine, and 2 , 5-Dimethylpiperazine, cis-2,6-dimethylpiperazine, N, N'-bis (3-aminopropyl) piperazine, 4,4'-cyclohexylmethanediamine, triethylenetetramine, 1- (2-aminoethyl) Examples include piperazine. Examples of the aromatic amine include 4,4'-diaminodiphenylmethane, 3,3'-dimethyl 4,4'-diaminodiphenylmethane, xylene diamine, phenylenediamine, 1,5-naphthendiamine, toluene-2,4-diamine, and the like. Toluene-2,6-diamine, 3,3'-dimethylbenzidine and the like can be mentioned. As the chain extender, the low molecular weight polyol and the low molecular weight polyamine may be used alone or in combination of two or more.

1.2.2 Method for Producing Polyurethane Continuous Porous Body The polyurethane continuous porous body can be produced by a conventionally known method. Hereinafter, as an example of a method for producing a polyurethane continuous porous body, a foaming method, a W / O emulsion method, and an extraction method will be described.

1.2.2.1 Foaming method As the foaming method, a reaction raw material containing at least a polyol component, a polyisocyanate component, a foaming agent, and a catalyst is used, and the polyol component and the polyisocyanate component are reacted and foamed. There is a way to make it.

The above-mentioned compounds may be used as the polyol component and the polyisocyanate component. The amount of the polyisocyanate component used may be adjusted based on the isocyanate index. The isocyanate index is preferably 80 or more, more preferably 90 or more, further preferably 100 or more, preferably 130 or less, and more preferably 120 or less. When the isocyanate index exceeds 100, it means that the amount of isocyanate groups is more than the amount of hydroxyl groups. When the isocyanate index is less than 100, the foam tends to be soft.

The isocyanate index is the mass ratio of the polyol component (including the chain extender component) / isocyanate component, which is calculated to be 100 when the polyisocyanate component chemically reacts with the hydroxyl group to which the polyisocyanate component reacts. It is an exponent to be expressed, and is expressed by the following formula.
Isocyanate index = {(actual amount of isocyanate) / (stoichiometrically calculated amount of isocyanate)} x 100

The foaming agent foams polyurethane. The foaming agent is water that reacts with a polyisocyanate component to generate carbon dioxide as a foaming agent; cyclopentane, isopentane, normal pentane, hexane that functions as a foaming agent by vaporizing with the reaction heat at the time of polyurethane formation. , Cyclohexane and other hydrocarbons; Halogen compounds such as dichloromethane, methylene chloride, trichlorofluoromethane, dichlorodifluoromethane, nonafluorobutylmethyl ether, nonafluorobutylethyl ether, pentafluoroethylmethyl ether, heptafluoroisopropylmethyl ether; liquefaction Examples thereof include liquefied carbon dioxide that functions as a foaming agent by mixing the carbon dioxide with the raw material under high pressure and vaporizing it at the time of foaming.

The catalyst promotes the urethanization reaction between the polyol component and the polyisocyanate component. As the catalyst, amines such as N, N, N-trimethylaminoethylpiperazine, triethylenediamine, dimethylethanolamine; organometallic compounds such as tin octylate; acetate; alkali metal alcoholate and the like are used.

When the urethanization reaction between the polyol component and the polyisocyanate component is carried out, a one-shot method, a prepolymer method or the like is adopted. The one-shot method is a method in which a polyol component and a polyisocyanate component are directly reacted. The prepolymer method is a method in which each part of a polyol component and a polyisocyanate component is reacted in advance to prepare a prepolymer having an isocyanate group or a hydroxyl group at the terminal, and the remaining polyol component or polyisocyanate component is reacted with the prepolymer. Is.

The polyurethane continuous porous body is preferably produced by slab molding. In slab molding, the reaction raw material (reaction mixture) mixed and stirred by the one-shot method is discharged onto a belt conveyor, and the reaction raw material is naturally foamed and cured at room temperature and atmospheric pressure while the belt conveyor moves. .. After that, it is cured in a drying oven and cut into a predetermined shape.

As a method for producing a polyurethane continuous porous body in which the polyurethane itself constituting the skeleton has hydrophilicity by the foaming method, (I) a method of blending a polyalkylene oxide polyol with a polyol component; (II) a reaction raw material. Method of blending an anionic surfactant as a foam stabilizer; (III) In the reaction raw material, as a foam stabilizer, the polyether moiety is one CH ₂ or 3 from the Si atom of the polyorganosiloxane moiety. _{A method of blending a polyorganosiloxane-polyether block copolymer bonded via two} consecutive CH groups; a method of blending (IV) an alkoxysilane represented by the general formula (1) with a reaction raw material; etc. Can be mentioned.
R ¹ −O − [Si (OR ² ) ₂ −O] _m −R ³ (1)
(In the formula, R ¹ , R ² and R ³ are the same or different, respectively, and represent a hydrocarbon group having 1 to 30 carbon atoms, and m represents an integer of 2 or more.)

Examples of the anionic surfactant used in (II) include sulfonates such as dodecylbenzene sulfonate; sulfate esters such as lauryl sulfate; sulfonates such as alkyldiphenyl ether disulfonate and dialkyl sulfosuccinate. ; Phosphate ester salts such as alkyl phosphates; and the like. By blending an anionic surfactant with the reaction raw material, the anionic surfactant migrates to the surface of the obtained polyurethane continuous porous body and becomes hydrophilic.

The foam stabilizer used in (III) is a polyorganosiloxane-polyether block copolymer composed of a polyorganosiloxane moiety, a polyether moiety, and a bonding portion thereof, and is a polyorganosiloxane moiety containing a silicon atom and a poly. Use a polyorganosiloxane-polyether block copolymer in which _{one CH 2} group or 3 or more consecutive CH ₂ groups are bonded between the first ether oxygen atoms in the ether moiety. Here, the block copolymer is a graft copolymer in which a part or all of the polyether portion forms a side chain and, if necessary, a terminal chain with respect to the polyorganosiloxane portion which is the main chain. It is used as a concept that includes a polymer, and is preferably a graft copolymer. When such a bond portion includes a silicon atom and the first ether oxygen atom of the polyether portion, it is represented by a Si-CH _2- O bond, a Si- (CH ₂ ) _3- O bond, and a Si- (CH _2). ) _4- O bond, etc. are exemplified, and there is an OH substituent at the tip of the first ether oxygen atom, such _{as Si- (CH 2} ) _3- O-CH ₂ -CH (OH) -CH _{2-O bond.} You may.

The polyorganosiloxane-polyether block copolymer preferably has a Si atom content of 0.8 to 9.5% by mass. When the amount of Si atom is 0.8% by mass or more, the foam conditioning effect is good, and when it is 9.5% by mass or less, the wettability of water to the polyurethane continuous porous body is further improved. Further, in the polyorganosiloxane-polyether block copolymer, the EO / PO ratio (molar ratio) of the polyether chain is 1. It is preferably 5 or less. When the EO / PO ratio is 1.5 or less, a highly breathable polyurethane continuous porous body can be obtained, and a high water permeability can be obtained.

In the alkoxysilane represented by the general formula (1) used in (IV) above, the ^{hydrocarbon groups represented by R 1} , R ² and R ³ are aliphatic hydrocarbon groups, alicyclic hydrocarbon groups and Any of the aromatic hydrocarbon groups may be used, and the number of carbon atoms thereof is preferably 1 to 5, more preferably 1 or 2. m is preferably 3 to 30, more preferably 4 to 20. The polyurethane continuous porous body produced in (IV) above is preferably brought into contact with water or water vapor after production.

1.2.2.2 W / O type emulsion method The W / O type emulsion method includes a step of preparing a W / O type emulsion, a step of shaping the obtained W / O type emulsion, and shaping. It has a step of polymerizing the obtained W / O type emulsion and a step of dehydrating the obtained hydrous polymer. The step of shaping the obtained W / O type emulsion and the step of polymerizing the shaped W / O type emulsion may be partially performed at the same time.

In the step of preparing the W / O type emulsion, the aqueous phase component and the oil phase component are mixed to obtain an emulsion state. A homogenizer or the like may be used as the shearing means for forming an emulsion. Examples of the aqueous phase component include ion-exchanged water. A water-soluble salt such as sodium carbonate may be added to the aqueous phase component. The oil phase component contains polyurethane, an ethylenically unsaturated monomer, and a polymerization initiator. The polyurethane can be produced by using the above-mentioned polyol component, polyisocyanate component, and if necessary, a chain extender component. The polyurethane may have an unsaturated double bond capable of radical polymerization at the end of the molecule. In this case, hydroxyethyl acrylate or the like may be blended as a raw material for polyurethane. Examples of the ethylenically unsaturated monomer include (meth) acrylic acid esters such as methyl (meth) acrylate and 2-ethylhexyl (meth) acrylate. The (meth) acrylic acid indicates acrylic acid and / or methacrylic acid. As the polymerization initiator, known ones can be used.

In the step of shaping the W / O type emulsion, the W / O type emulsion is shaped into a desired shape. The shaping method is not particularly limited, and examples thereof include a method in which a W / O type emulsion is continuously supplied onto a running belt and shaped into a smooth sheet shape on the belt.

In the step of polymerizing the shaped W / O type emulsion, the W / O type emulsion is polymerized to obtain a hydrous polymer. In this step, an appropriate polymerization method may be adopted depending on the polymerization initiator used. Examples of the polymerization method include a method of polymerizing by heating, a method of polymerizing by irradiation with ultraviolet rays, and the like.

In the step of dehydrating the W / O type emulsion, the aqueous phase component is removed from the hydrous polymer. The method for removing the aqueous phase component is not particularly limited, and examples thereof include vacuum drying, freeze drying, squeezing drying, and drying in a hot oven.

1.2.2.3 Extraction method In the extraction method, a step of kneading polyurethane and a pore-forming agent, a step of molding the obtained kneaded composition, and a step of molding the obtained molded product with an aqueous solvent into pores. It has a step of extracting a forming agent.

In the step of kneading the polyurethane and the pore forming agent, the polyurethane and the pore forming agent are kneaded to prepare a kneading composition. The polyurethane can be produced by using the above-mentioned polyol component, polyisocyanate component, and if necessary, a chain extender component. The pore-forming agent is not particularly limited as long as it can be extracted with an aqueous solvent and can form pores in polyurethane. Examples of the pore-forming agent include water-soluble inorganic salts and water-soluble polymer materials. Examples of the water-soluble inorganic salt include calcium chloride and magnesium chloride. Examples of the water-soluble polymer material include polyvinyl alcohol, polyethylene oxide, water-soluble vinylon, hydroxyethyl cellulose, methyl cellulose, carboxymethyl cellulose, starches (corn starch, wheat starch, potato starch) and the like.

Examples of the method of kneading the polyurethane and the pore forming agent include a method of heating and melting and kneading, and a method of adding a solvent and kneading. Examples of the solvent include organic solvents such as acetone, dimethylformamide, methyl ethyl ketone and tetrahydrofuran.

In the step of molding the kneading composition, the kneading composition obtained above is molded into a desired shape. The molding method is not particularly limited, and molding is performed by a compression molding method, an extrusion molding method, an injection molding method, or the like. After molding, the molded body is solidified. At this time, in the case of heat molding, it is solidified by cooling. When molding is performed by adding a solvent, it is solidified by removing the solvent.

In the step of extracting the pore-forming agent from the molded product with an aqueous solvent, pores are formed inside the molded product by extracting the pore-forming agent using the aqueous solvent. Examples of the aqueous solvent include water, water-soluble alcohol and the like.

1.2.2.4 Heat compression molding It is preferable that the polyurethane continuous porous body is produced by the above-mentioned production method and then subjected to heat compression molding. By performing the heat compression treatment, the water permeability in the thickness direction and the diffusivity in the horizontal direction of the polyurethane continuous porous body can be improved.

The thermal compression molding can be performed, for example, by subjecting a flat polyurethane continuous porous body to an open state on the side surface and uniformly compressing and plastically deforming the thickness direction. The heating temperature (hot plate temperature) of the heat compression molding is preferably 170 ° C. or higher, preferably 210 ° C. or lower, and more preferably 190 ° C. or lower. The molding time of the heat compression molding is preferably 1 minute or more, more preferably 2 minutes or more and 10 minutes or less, and more preferably 6 minutes or less. When the heat compression molding is performed, the compressibility (thickness before molding / thickness after molding) of the polyurethane continuous porous body after heat compression molding is preferably 1.5 or more, more preferably 2.0 or more. It is preferably 7.5 or less, and more preferably 6.0 or less.

2 Absorber The absorber absorbs and retains body fluids. The absorber is composed of at least one water absorbing layer.

2.1 Water-absorbent layer The water-absorbent layer preferably contains a water-absorbent resin powder as a water-absorbent material. As the water-absorbent resin powder, those conventionally used for absorbent articles can be used.

2.1.1 Water-absorbent resin powder The water-absorbent resin powder is preferably one in which the surface of (A) the crosslinked polymer is coated with (B) a surface modifier. It is preferable that the (B) surface modifier exists only on the surface of the (A) crosslinked polymer and does not exist inside the (A) crosslinked polymer. Since the (B) surface modifier is not present inside the (A) crosslinked polymer, the mechanical strength of the (A) crosslinked polymer is improved, and the load is not deteriorated without deteriorating the absorption performance of the water-absorbent resin powder. The underflow rate can be increased.

2.1.1.1 (A) Crosslinked Polymer First, (A) the crosslinked polymer will be described. The crosslinked polymer (A) is preferably a polymer of a monomer composition containing (a1) a hydrophilic group-containing monomer and (a2) an internal crosslinking agent.

The (a1) hydrophilic group-containing monomer has at least one hydrophilic group and at least one ethylenically unsaturated group. The (a1) hydrophilic group-containing monomer is preferably a monomer having one ethylenically unsaturated group, and the ethylenically unsaturated group is preferably a vinyl group.

Examples of the hydrophilic group include a carboxyl group, a sulfo group, a sulfooxy group, a phosphono group, a hydroxyl group, a carbamoyl group, an amino group, and salts thereof. Among these, as the hydrophilic group, a salt of a carboxyl group and a salt of a sulfo group are preferable. Examples of the salt include alkali metal salts such as lithium, sodium and potassium; alkaline earth metal salts such as magnesium and calcium; and ammonium salts. The ammonium salt may be either a salt of a primary to tertiary amine 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 particularly preferable, from the viewpoint of absorption characteristics.

Examples of the (a1-1) monomer having a carboxyl group and / or a salt thereof include unsaturated carboxylic acids having 3 to 30 carbon atoms having one ethylenically unsaturated group and / or salts thereof. Specific examples of the monomers include unsaturated monocarboxylic acids such as (meth) acrylic acid, crotonic acid, and cinnamic acid and / or salts thereof; unsaturated dicarboxylic acids such as maleic acid, fumaric acid, citraconic acid, and itaconic acid and /. Or salts thereof; unsaturated dicarboxylics such as maleic acid monobutyl ester, fumaric acid monobutyl ester, maleic acid ethylcarbitol monoester, fumaric acid ethylcarbitol monoester, citraconic acid monobutyl ester, and itaconic acid glycol monoester. Examples thereof include monoalkyl (1 to 8 carbon atoms) esters of acids and / or salts thereof. In addition, "(meth) acrylic" means "acrylic" and / or "methacryl".

As the (a1-1) monomer having a sulfo group and / or a salt thereof, a sulfonic acid having 2 to 30 carbon atoms having one ethylenically unsaturated group and / or a salt thereof is preferable. Specific examples of the monomer include aliphatic vinyl sulfonic acids such as vinyl sulfonic acid and (meth) allyl sulfonic acid; aromatic vinyl sulfonic acids such as styrene sulfonic acid and α-methylstyrene sulfonic acid; and (meth) acryloxipropyl sulfonic acid. Acid, 2-Hydroxy-3- (meth) acryloxypropyl sulfonic acid, 2- (meth) acryloylamino-2,2-dimethylethanesulfonic acid, 3- (meth) acryloxietan sulfonic acid, 2- (meth) (Meta) acryloyl-containing alkyl sulfonic acids such as acrylamide-2-methylpropansulfonic acid and 3- (meth) acrylamide-2-hydroxypropanesulfonic acid; alkyl (meth) allylsulfosuccinates and the like can be mentioned.

Examples of the (a1-1) monomer having a sulfooxy group and / or a salt thereof include a sulfate ester of a hydroxyalkyl (meth) acrylate; a sulfate ester of a polyoxyalkylene mono (meth) acrylate.

Examples of the (a1-1) monomer having a phosphono group and / or a salt thereof include a phosphoric acid monoester of hydroxyalkyl (meth) acrylic acid, a phosphoric acid diester of hydroxyalkyl (meth) acrylic acid, and (meth) acrylic acid. Acrylic phosphonic acid and the like can be mentioned.

Examples of the (a1-1) monomer having a hydroxyl group include (meth) allyl alcohol and monoethylene unsaturated alcohol having 3 to 15 carbon atoms such as (meth) propenyl alcohol; alkylene glycol having 2 to 20 carbon atoms and glycerin. , Sorbitane, diglycerin, pentaerythritol, polyalkylene (2-4 carbon atoms) glycol (weight average molecular weight 100-2000) and other 2- to 6-valent polyols monoethylene unsaturated carboxylic acid esters or monoethylene unsaturated Examples include ether. Specific examples of the monomer include hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, triethylene glycol (meth) acrylate, polyoxyethylene-oxypropylene mono (meth) allyl ether and the like.

Examples of the (a1-1) monomer 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 carbons 1-8) acrylamide such as di-n- or i-propylacrylamide; N-hydroxyalkyl (alkyl (meth) acrylamide, N-hydroxyethyl (meth) acrylamide, etc. Examples thereof include N, N-dihydroxyalkyl (1 to 8 carbon atoms) (meth) acrylamide such as N, N-dihydroxyethyl (meth) acrylamide; N, N-dihydroxyethyl (meth) acrylamide and the like. As the unsaturated monomer having a group composed of an amide, vinyl lactam having 5 to 10 carbon atoms (N-vinylpyrrolidone, etc.) or the like can also be used.

Examples of the (a1-1) monomer having an amino group include an amino group-containing ester of a monoethylenically unsaturated mono- or di-carboxylic acid and an amino group-containing amide of a monoethylene unsaturated mono- or di-carboxylic acid. Can be mentioned. As the amino group-containing ester of monoethylene unsaturated mono- or di-carboxylic acid, dialkylaminoalkyl (meth) acrylate, di (hydroxyalkyl) aminoalkyl ester, morpholinoalkyl ester and the like can be used, and dimethylaminoethyl (meth) can be used. ) Acrylic, diethylamino (meth) acrylate, morpholinoethyl (meth) acrylate, dimethylaminoethyl fumarate, dimethylaminoethylmalate and the like can be mentioned. As the amino group-containing amide of the monoethylenically unsaturated mono- or di-carboxylic acid, monoalkyl (meth) acrylamide is preferable, and dimethylaminoethyl (meth) acrylamide, diethylaminoethyl (meth) acrylamide and the like can be mentioned. In addition to these, vinylpyridines such as 4-vinylpyridine and 2-vinylpyridine can also be used as the water-soluble ethylenically unsaturated monomer having an amino group.

As the (a1) hydrophilic group-containing monomer, (meth) acrylic acid, a monomer having at least one hydrophilic substituent and one acryloyl group or methacryloyl group, and salts thereof are preferable.

The (a1) hydrophilic group-containing monomer also includes a monomer that becomes a hydrophilic group-containing monomer (hereinafter, may be referred to as “(a1-1) hydrolyzable monomer”) by (a1-1) hydrolysis. included.

The (a1-1) hydrolyzable monomer is hydrolyzed by the action of water at 50 ° C. and, if necessary, a catalyst (acid, base, etc.) to produce the (a1) hydrophilic group-containing monomer. The hydrolysis of the (a1-1) hydrolyzable monomer may be performed during or after the polymerization of the (A) crosslinked polymer, or both of them, but from the viewpoint of the molecular weight of the obtained water-absorbent resin powder, etc. After polymerization is preferable.

The hydrolyzable monomer (a1-1) has at least one hydrolyzable substituent which becomes a hydrophilic group by hydrolysis. Examples of the hydrolyzable substituent include a group containing an acid anhydride, a group containing an ester bond, a cyano group and the like.

Examples of the monomer having a group containing an acid anhydride include unsaturated dicarboxylic acid anhydrides having 4 to 20 carbon atoms, maleic anhydride, itaconic anhydride, citraconic anhydride and the like. Examples of the 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 and (meth) allyl acetate. Examples thereof include esters of monoethylene unsaturated alcohols such as. Examples of the monomer having a cyano group include (meth) acrylonitrile and a vinyl group-containing nitrile compound having 3 to 6 carbon atoms such as 5-hexenenitrile.

As the monomer constituting the (A) crosslinked polymer, in addition to the (a1) hydrophilic group-containing monomer, other vinyl monomers copolymerizable with these can be used. As the other vinyl monomer, a non-crosslinkable hydrophobic vinyl monomer or the like can be used, but the vinyl monomer is not limited thereto. When the other vinyl monomer is used, the content (mol%) of the other vinyl monomer is preferably 0.01 mol% to 5 mol% with respect to (a1) 100 mol% of the hydrophilic group-containing monomer. It is preferably 0.05 mol% to 3 mol%. From the viewpoint of absorption characteristics, the content of the other vinyl monomer is most preferably 0 mol%.

The (a2) internal cross-linking agent includes (a2-1) an internal cross-linking agent having two or more ethylenically unsaturated groups; and (a2-2) having at least one functional group capable of reacting with a hydrophilic group. Moreover, an internal cross-linking agent having at least one ethylenically unsaturated group; (a2-3) an internal cross-linking agent having two or more functional groups capable of reacting with a hydrophilic group can be mentioned.

Examples of the (a2-1) internal cross-linking agent include bis (meth) acrylamide having 8 to 12 carbon atoms, poly (meth) acrylate of a polyol having 2 to 10 carbon atoms, polyallylamine having 2 to 10 carbon atoms, and 2 carbon atoms. Examples thereof include poly (meth) allyl ethers of 10 and 10 polyols. Specific examples of these include N, N'-methylenebis (meth) acrylamide, ethylene glycol di (meth) acrylate, poly (polymerization degree 2 to 5) ethylene glycol di (meth) acrylate, and propylene glycol di (meth) acrylate. Glycerin (di or tri) acrylate, trimethylolpropane triacrylate, diallylamine, triallylamine, triallyl cyanurate, triallyl isocyanurate, tetraaryloxyethane, pentaerythritol diallyl ether, pentaerythritol triallyl ether, pentaerythritol tetraallyl ether And diglycerin di (meth) acrylate and the like.

Examples of the (a2-2) internal cross-linking agent include 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 isocyanato having 4 to 8 carbon atoms. Examples thereof include ethylenically unsaturated compounds having a group. Specific examples of these include glycidyl (meth) acrylate, N-methylol (meth) acrylamide, hydroxyethyl (meth) acrylate, isocyanatoethyl (meth) acrylate and the like.

Examples of the (a2-3) internal cross-linking agent include polyhydric alcohols, polyhydric glycidyl, polyvalent amines, polyvalent aziridine, polyvalent isocyanate and the like. 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)} and chemitite HZ-22 {1,6-- manufactured by Nippon Shokubai Kagaku Kogyo Co., Ltd. Hexamethylenediethyleneurea} and Chemitite DZ-22 {diphenylmethane-bis-4, 4'-N, N'-diethyleneurea} and the like. Examples of the polyisocyanate compound include 2,4-tolylene diisocyanate and hexamethylene diisocyanate. These internal cross-linking agents may be used alone or in combination of two or more.

As the (a2) internal cross-linking agent, from the viewpoint of absorption performance (particularly, absorption amount, absorption rate, etc.) and the like, (a2-1) an internal cross-linking agent having two or more ethylenically unsaturated groups is preferable, and the number of carbon atoms is 2 to 2. Poly (meth) allyl ethers of 10 polyols are more preferred, triallyl cyanurate, triallyl isocyanurate, tetraallyloxyethane or pentaerythritol triallyl ethers are even more preferred, and pentaerythritol triallyl ethers are most preferred.

The content (mol%) of the (b) internal cross-linking agent is preferably 0.001 mol% to 5 mol%, more preferably 0.005 mol%, based on 100 mol% of the (a1) hydrophilic group-containing monomer. It is ~ 3 mol%, more preferably 0.01 mol% ~ 1 mol%. Within this range, the absorption performance (particularly the absorption amount and the absorption rate) becomes even better.

As the polymerization form of the crosslinked polymer (A), conventionally known methods and the like 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 liquid at the time of polymerization may be a thin film or a spray. As the polymerization control method, an adiabatic polymerization method, a temperature control polymerization method, an isothermal polymerization method and the like can be applied. When a suspension polymerization method or a reverse phase suspension polymerization method is applied as the polymerization method, conventionally known dispersants such as sucrose ester, phosphoric acid ester and sorbitan ester, and povar, α-olefin- Protective colloids such as maleic anhydride copolymer and polyethylene oxide can be used. Further, in the case of the reverse phase suspension polymerization method, the 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 it is advantageous in terms of production cost.

The hydrogel {consisting of a crosslinked polymer and water} obtained by polymerization can be shredded as needed. 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 step is further improved. The shredding can be performed by a known method, and can be shredded using a conventional shredding device such as a Beck's mill, a rubber chopper, a pharma mill, a minced machine, an impact type crusher and a roll type crusher.

When a solvent (organic solvent, water, etc.) is used 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 10% by mass or less, more preferably 1% by mass, based on the mass (100% by mass) of the crosslinked polymer. It is as follows. 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 becomes further good. When water is contained in the solvent, the water content (% by mass) after distillation is preferably 0% by mass to 20% by mass, more preferably 1% by mass to 10% by mass, based on the mass (100% by mass) of the crosslinked polymer. It is 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.

The content and moisture content of the organic solvent are determined by an infrared moisture measuring instrument {JE400 manufactured by KETT Co., Ltd .: 120 ± 5 ° C., 30 minutes, atmospheric humidity 50 ± 10% RH before heating, lamp specification 100V, 40W. }, It is obtained from the mass loss of the measurement sample before and after heating. As a method for distilling off the solvent (including water), a method of distilling off (drying) with hot air at a temperature of 80 ° C. to 230 ° C., a thin film drying method using a drum dryer heated to 100 ° C. to 230 ° C., etc. (Heating) Vacuum drying method, freeze drying method, infrared drying method, decantation, filtration and the like can be applied.

The crosslinked polymer (A) can be pulverized after drying. The crushing method is not particularly limited, and for example, a normal crushing device such as a hammer type crusher, an impact type crusher, a roll type crusher, and a shet airflow type crusher can be used. The particle size of the pulverized (A) crosslinked polymer can be adjusted by sieving or the like, if necessary. The weight average particle size (μm) of the crosslinked polymer (A) when screened as necessary is preferably 100 μm to 800 μm, more preferably 200 μm to 700 μm, further preferably 250 μm to 600 μm, and particularly preferably 300 μm to 500 μm. It is preferably 350 μm to 450 μm. When the weight average particle size (μm) of the crosslinked polymer (A) is within the above range, the absorption performance is further improved.

The weight average particle size was determined by 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 Canvas, 1984). , Page 21). That is, the 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 the saucer from the top. Place about 50 g of the measurement particles in the uppermost sieve and shake with a low-tap test sieve shaker for 5 minutes. Weigh the measured particles on each sieve and saucer, and take the total as 100% by weight to obtain the weight fraction of the particles on each sieve, and use this value as the logarithmic probability paper {the horizontal axis is the mesh size of the sieve (particle size). ), The vertical axis is the weight fraction}, then a line connecting each point is drawn to obtain the particle size corresponding to the weight fraction of 50% by weight, and this is taken as the weight average particle size.

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

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

The crosslinked polymer (A) can be surface-crosslinked if necessary. As the cross-linking agent (surface cross-linking agent) for performing surface cross-linking, the same one as the (a2) internal cross-linking agent can be used. As the surface cross-linking agent, from the viewpoint of absorption performance of the water-absorbent resin powder, (a2-3) internal cross-linking agent is preferable, polyhydric glycidyl is more preferable, and ethylene glycol diglycidyl ether and glycerin diglycidyl ether are more preferable. The most preferable is ethylene glycol diglycidyl ether.

In the case of surface cross-linking, the amount of the surface cross-linking agent used is preferably 0.001 part by mass to 7 parts by mass, and more preferably 0.003 parts by mass to 4 parts by mass with respect to 100 parts by mass of the (A) crosslinked polymer. Is. When the amount of the surface cross-linking agent used is within the above range, the absorption performance is further improved. Surface cross-linking can be achieved by a method of spraying or impregnating the (A) cross-linked polymer with an aqueous solution containing a surface cross-linking agent and then heat-treating (100 to 200 ° C.).

2.1.1.2 (B) Surface modifiers (B) Surface modifiers include aluminum sulfate, potassium syrup, ammonium syrup, sodium syrup, (poly) aluminum chloride, and hydrates thereof. Valuable metal compound; Polycationic compound such as polyethyleneimine, polyvinylamine, polyallylamine; Inorganic fine particles; (B1) Surface modifier containing hydrocarbon group; (B2) Surface modification containing hydrocarbon group having fluorine atom Pledge agents; and (B3) surface modifiers having a polysiloxane structure and the like can be mentioned.

Examples of the inorganic fine particles include oxides such as silicon oxide, aluminum oxide, iron oxide, titanium oxide, magnesium oxide, and zirconium oxide, carbides such as silicon carbide and aluminum carbide, nitrides such as titanium nitride, and the like. (For example, zeolite, talc, etc.) and the like. 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 the 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 in accordance with JIS Z8830: 2001 (nitrogen, volumetric method, multipoint method).

(B1) Examples of the surface modifier containing a hydrocarbon group include polyolefin resins, polyolefin resin derivatives, polystyrene resins, polystyrene resin derivatives, waxes, long-chain fatty acid esters, long-chain fatty acids and salts thereof, and 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 10 to 1,000,000 obtained by polymerizing olefins having 2 to 4 carbon atoms such as ethylene, propylene, isobutylene and isoprene. Specific examples of the polyolefin resin include polyethylene, polypropylene, polyisobutylene, poly (ethylene-isobutylene), isoprene and the like. Examples of the polyolefin resin derivative include maleic acid-modified polyethylene, chlorinated polyethylene, maleic acid-modified polypropylene, ethylene-acrylic acid copolymer, ethylene-maleic anhydride copolymer, isobutylene-maleic anhydride copolymer, and maleic anhydride. Examples thereof include polybutadiene, ethylene-vinyl acetate copolymer and maleic anhydride of ethylene-vinyl acetate copolymer.

As the polystyrene resin, a polymer having a weight average molecular weight of 10 to 1,000,000 or the like 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 10 to 1,000,000 is preferable. The content of styrene is preferably at least 50% by mass based on 100% by mass of the polystyrene derivative. Specific examples of the polystyrene resin derivative include a styrene-maleic anhydride copolymer, a styrene-butadiene copolymer, and a 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. As the long-chain fatty acid ester, sucrose stearic acid monoester, sucrose stearic acid diester, and sucrose stearic acid triester are preferable, and sucrose stearic acid monoester and sucrose stearic acid monoester are more preferable, from the viewpoint of leakage resistance of the absorbent article. It is a sucrose stearic acid diester. As the long-chain fatty acid and its salt, a fatty acid having 8 to 30 carbon atoms and its salt are preferable, and from the viewpoint of leakage resistance of the absorbent article, the long-chain fatty acid and its salt include Zn stearate and Ca stearate. Mg stearate and Al stearate are preferable, and Mg stearate is more preferable.

Examples of the long-chain fatty 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 fatty alcohol is preferably palmityl alcohol, stearyl alcohol, or oleyl alcohol, and more preferably stearyl alcohol.

(B2) Examples of the surface modifier containing a hydrocarbon group having a fluorine atom include perfluoroalkane, perfluoroalkene, perfluoroaryl, perfluoroalkyl ether, perfluoroalkylcarboxylic acid or a salt thereof, and perfluoroalkyl alcohol. , And a mixture of two or more of these. Examples of the perfluoroalkane include trifluoromethane, pentafluoroethane, pentafluoropropane, heptafluoropropane, heptafluorobutane, nonafluorohexane, tridecafluorooctane, and heptadecafluorododecane. Examples of the perfluoroalkene include trifluoroethylene, pentafluoropropene, trifluoropropene, heptafluorobutene, nonafluorohexene, tridecafluorooctene, and heptadecafluorododecene. Examples of perfluoroaryl include trifluorobenzene, pentafluorotoluene, trifluoronaphthalene, heptafluorobenzene, nonafluoroxylene, tridecafluorooctylbenzene, and heptadecafluorododecylbenzene. Examples of the perfluoroalkyl ether include ditrifluoromethyl ether, dipentafluoroethyl ether, dipentafluoropropyl ether, diheptafluoropropyl ether, diheptafluorobutyl ether, dinonafluorohexyl ether, ditridecafluorooctyl ether, and didiheptafluoropropyl ether. Examples thereof include heptadecafluorododecyl ether and the like. Examples of the perfluoroalkylcarboxylic acid or a salt thereof include pentafluoroethane acid, pentafluoropropane acid, heptafluoropropane acid, heptafluorobutanoic acid, nonafluorohexanoic acid, tridecafluorooctanoic acid, and heptadecafluorododecanoic acid. Alternatively, these metal salts can be mentioned. As the metal salt, an alkali metal salt or an alkaline earth metal salt is preferable. Examples of the perfluoroalkyl alcohol include pentafluoroethanol, pentafluoropropanol, heptafluoropropanol, heptafluorobutanol, nonafluorohexanol, tridecafluorooctanol, and heptadecafluorododecanol, and ethylene of these alcohols. Examples thereof 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 a perfluoroalkylcarboxylic acid and a perfluoroalkyl alcohol, and for example, a mixture of pentafluoroethane acid and pentafluoroethanol is preferable.

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

The position of the organic group (modifying group) of the modified silicone such as polyether-modified polysiloxane, carboxy-modified polysiloxane, epoxy-modified polysiloxane, and amino-modified polysiloxane is not particularly limited, but both the side chain of polysiloxane and polysiloxane It may be either a terminal, one end of polysiloxane, or both side chains and both ends of polysiloxane. Of these, from the viewpoint of absorption characteristics, both the side chain of polysiloxane and the side chain of polysiloxane and both ends are preferable, and more preferably both the side chain of polysiloxane and both ends.

Examples of the organic group (modifying group) of the polyether-modified polysiloxane include 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 to 40, more preferably 5 to 30, and 7 to 1 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 an oxyethylene group and an oxypropylene group are contained, the content (% by mass) of the oxyethylene group and the oxyprocylene group is preferably 1% by mass to 30% by mass in 100% by mass of the polyether-modified polysiloxane. 3% by mass to 25% by mass is more preferable, and 5% by mass to 20% by mass is further preferable. When the content of the oxyethylene group and the oxyprocylene group is within the above range, the absorption characteristics are further improved.

The organic group (modifying group) of the carboxy-modified polysiloxane includes a group containing a carboxy group, and the organic group (modifying group) of the epoxy-modified polysiloxane includes a group containing an epoxy group and is amino-modified. Examples of the organic group (modifying group) of the polysiloxane include a group containing an amino group (1, 2, 3rd grade amino group) and the like. The organic group (modifying group) content (g / mol) of these modified silicones is preferably 200 to 11000, more preferably 600 to 8000, still more preferably 1000 to 4000, as a carboxy equivalent, an epoxy equivalent or an amino equivalent. 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). The epoxy equivalent is determined in accordance with JIS K7236 (2001). The amino equivalent is measured according to "8. Potentiometric titration method (base value / hydrochloric acid method)" of JIS K2501 (2003).

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.

As the surface modifier (B), 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.

The method for treating the (A) crosslinked polymer with the (B) surface modifier is particularly as long as the method is such that the (B) surface modifier is present on the surface of the (A) crosslinked polymer. Not limited. However, (B) the surface modifier is not mixed with the hydrogel of (A) the crosslinked polymer or the polymer solution before polymerizing the (A) crosslinked polymer, but with the dried product of (A) the crosslinked polymer. This is preferable from the viewpoint of controlling the amount of the (B) surface modifier on the surface. The mixing is preferably performed uniformly.

The shape of the water-absorbent resin powder is not particularly limited, and examples thereof include amorphous crushed form, phosphorus flaky form, pearl form, and rice granule. Of these, the amorphous crushed form is preferable from the viewpoint that it is easily entangled with the fibrous material for use in disposable diapers and the like and there is no concern that it will fall off from the fibrous material. The water-absorbent resin powder contains additives such as preservatives, antifungal agents, antibacterial agents, antioxidants, ultraviolet absorbers, colorants, fragrances, deodorants, inorganic powders and organic fibrous substances. Can be done.

2.1.1.3 Physical properties The water-absorbent resin powder preferably satisfies the following requirements (a) to (d).
(A) Bulk density: 0.50 g / ml to 0.70 g / ml
(B) Absorption rate by vortex method: 25 seconds to 75 seconds (c) Liquid flow rate under load: 40 seconds or less (d) Moisture absorption blocking rate: 5% or less

The water-absorbent resin powder that satisfies the above requirements (a) to (d) is less likely to cause gel blocking and has a high liquid passing speed under load, so that the body fluid can be immediately taken into the water-absorbent layer. .. Since the second sheet has excellent water permeability, if the absorption rate of the absorber is slow, the body fluid may stay in the second sheet. However, if the absorber contains a water-absorbent resin powder that satisfies the above requirements (a) to (d), the body fluid that has reached the absorber can be immediately taken into the water-absorbent layer, so that the absorption rate of the absorbent article is further increased. improves.

The water-absorbent resin powder (a) preferably has a bulk density of 0.50 g / ml or more, more preferably 0.51 g / ml or more, still more preferably 0.52 g / ml or more, and 0.70 g / ml or less. Is preferable, and more preferably 0.68 g / ml or less, still more preferably 0.65 g / ml or less. The bulk density is an index of the shape of the water-absorbent resin powder. When the bulk density is within the above range, voids as passages for body fluids are likely to be formed between the water-absorbent resin powders. As a result, the absorption rate and the repeated absorption rate are improved. The method for measuring the bulk density will be described later.

The water-absorbent resin powder has an absorption rate of (b) vortex method preferably 25 seconds or more, more preferably 27 seconds or more, further preferably 30 seconds or more, preferably 75 seconds or less, more preferably 70 seconds. Below, it is more preferably 65 seconds or less. The absorption rate by the vortex method is evaluated by measuring the time (seconds) for absorbing body fluid. Therefore, the shorter the measurement time (seconds), the higher the absorption rate. When the absorption rate is 25 seconds or more, the stability of the water-absorbent resin powder to urine, particularly the stability under load, becomes better. Further, when the absorption rate is 75 seconds or less, the excretion rate of the body fluid is high, and even when a large amount of the body fluid is excreted at one time, the body fluid can be sufficiently absorbed. As a result, the occurrence of liquid leakage is further suppressed.

The water-absorbent resin powder (c) has a liquid passing speed under load of 40 seconds or less, more preferably 30 seconds or less, still more preferably 20 seconds or less. The liquid passing rate under load is evaluated by measuring the time (seconds) through which a certain amount of liquid passes in a state where a load is applied to the water-absorbent resin powder that has been swollen by absorbing water in advance. Therefore, the shorter the measurement time (seconds), the higher the absorption rate. When the liquid passing speed under the load is 40 seconds or less, it is possible to suppress the occurrence of the diffusion disorder of the body fluid inside the absorber. Therefore, the occurrence of liquid leakage is further suppressed.

The water-absorbent resin powder (d) has a moisture absorption blocking rate of 5% or less, more preferably 4% or less, still more preferably 3% or less. When the moisture absorption blocking rate is 5% or less, the water absorption resin powder is less likely to aggregate. Therefore, the occurrence of reversion of the excreted body fluid is further suppressed.

The water-absorbent resin powder (e) has an absorption ratio of 40 g / g or more, more preferably 42 g / g or more, still more preferably 44 g / g or more, and 55 g / g or less. It is preferable, more preferably 53 g / g or less, still more preferably 51 g / g or less. The absorption ratio is a measure of how much water the water-absorbent resin powder can absorb. When the absorption ratio is 40 g / g or more, the amount of the water-absorbent resin powder required to achieve the desired absorption capacity can be reduced, so that the absorber can be made thinner. When the absorption ratio is 55 g / g or less, the stability of the water-absorbent resin powder to urine is further improved.

The water-absorbent resin powder (f) has a water retention amount of 20 g / g or more, more preferably 22 g / g or more, still more preferably 24 g / g or more, preferably 45 g / g or less, and more preferably 43 g. / G or less, more preferably 40 g / g or less. The amount of water retained is a measure of how much the water-absorbent resin powder can retain the absorbed liquid. When the water retention amount is 20 g / g or more, the amount of the water-absorbent resin powder required to achieve the desired retention capacity can be reduced, so that the absorber can be made thinner. When the water retention amount is 45 g / g or less, the stability of the water-absorbent resin powder to urine is further improved.

The bulk density of the water-absorbent resin powder, the absorption rate by the vortex method, the liquid passing rate under load, the absorption ratio, and the water retention amount are determined by, for example, the composition of the crosslinked 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 the conditions and the like.

2.1.2 Fiber base material The water absorption layer preferably contains a fiber base material. By containing the fiber base material, the shape retention of the water absorption layer is enhanced, and the fiber base material secures the passage of the body fluid, and the absorption rate is further improved. Examples of the fiber base material include water-absorbent fibers and heat-sealing fibers. Examples of the water-absorbent fiber include pulp fiber, cellulose fiber, rayon, and acetate fiber. As the heat-sealing fiber, for example, polyolefin fibers such as polyethylene and polypropylene, polyester fibers, composite fibers and the like are used.

When the water-absorbent layer contains a fiber base material, the content of the water-absorbent resin powder in the water-absorbent layer is preferably 60% by mass or more, more preferably 62% by mass or more, still more preferably 65% by mass or more. The content of the fiber base material in the water absorption layer is preferably 20% by mass or less, more preferably 18% by mass or less, and further preferably 16% by mass or less.

When the water-absorbent layer contains the water-absorbent resin powder and the fiber base material, the content of the water-absorbent resin powder on the side surface of the second sheet of the water-absorbent layer is the content of the water-absorbent resin powder on the side surface of the back sheet of the water-absorbent layer. It is preferably higher than the rate. By increasing the content of the water-absorbent resin powder on the side surface of the second sheet of the water-absorbent layer, it is possible to suppress the backflow of body fluid from the water-absorbent layer to the second sheet. The content of the water-absorbent resin powder on the side surface of the second sheet of the water-absorbent layer is higher than the content of the water-absorbent resin powder on the side surface of the back sheet of the water-absorbent layer. However, it can be confirmed by measuring the number of water-absorbent resin powders.

2.2 Base material The absorber may be formed of only the water absorption layer or may have a base material. Examples of the base material include a paper sheet such as tissue paper and a liquid-permeable non-woven fabric sheet. Examples of the absorber having the base material include a mode in which the water-absorbent material is fixed to the base material, and a mode in which the water-absorbent material is wrapped in the base material and molded into a desired shape.

3 Top sheet The top sheet is arranged on the most wearer side of the absorbent article, and quickly captures the wearer's body fluid and moves it to the absorber. As the top sheet, a liquid-permeable sheet material, for example, a non-woven fabric formed of hydrophilic fibers can be used. The non-woven fabric used as the top sheet is, for example, a point-bonded non-woven fabric, an air-through non-woven fabric, a spunlace non-woven fabric, and a spunbonded non-woven fabric, and cellulose, rayon, cotton, or the like is usually used as the hydrophilic fibers forming these non-woven fabrics. .. As the top sheet, a liquid-permeable non-woven fabric formed of hydrophobic fibers (for example, polypropylene, polyethylene, polyester, polyamide) whose surface is hydrophilized with a surfactant may be used.

4 Back sheet The back sheet is arranged on the outermost surface side of the absorbent article, and prevents body fluids and the like from leaking to the outside. Examples of the impermeable sheet used for the back sheet include water-repellent or impermeable non-woven fabrics (for example, spans) formed of hydrophobic fibers (for example, polypropylene, polyethylene, polyester, polyamide, nylon). Bond non-woven fabric, melt-blow non-woven fabric, SMS (spunbond, melt-blow, spunbond) non-woven fabric), water-repellent or impermeable plastic film are used, and the body fluid that reaches the impermeable sheet is outside the absorbent article. Prevent oozing out. 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 the comfort of the wearer. Further, a paper sheet may be arranged between the plastic film and the absorber for further diffusivity and shape stability.

5 Structure of the absorbent article The absorbent article includes a liquid-permeable top sheet, a second sheet arranged on the outer surface side of the top sheet, an absorber arranged on the outer surface side of the second sheet, and the absorption. It has an impermeable backsheet arranged on the outer surface side of the body.

5.1 Second sheet The plan view shape of the second sheet is not particularly limited, and examples thereof include a rectangular type, an hourglass type, a gourd type, and a battledore type. The plan view shape of the second sheet may be the same as the plan view shape of the top sheet, but is preferably smaller than the plan view shape of the top sheet. The area of the second sheet is preferably 20% or more, more preferably 30% or more, preferably 80% or less, and more preferably 70% or less, when the area of the top sheet is 100%. The second sheet is preferably arranged along the length direction of the absorbent article.

It is preferable that the second sheet is arranged so that at least a part thereof is in contact with the top sheet. By bringing the second sheet into contact with the top sheet, the body fluid taken into the top sheet can be transferred to the second sheet more quickly, and the absorption rate is further improved.

The second sheet is preferably bonded to the top sheet with an adhesive. Examples of the adhesive include hot melt adhesives, and rubber-based hot melt adhesives are preferable. When an adhesive is arranged between the top sheet and the second sheet, the arrangement of the adhesive may be appropriately adjusted within a range that does not impair the effects of the present invention. Examples of the arrangement mode of the adhesive include streaks, dots, lattices, spirals and the like. The adhesive is preferably continuous in the longitudinal direction of the absorbent article and intermittently placed in the width direction of the absorbent article. Specifically, it is preferable to arrange the absorbent article in a streak shape (width 0.8 mm to 1.2 mm, interval 2.0 mm to 4.0 mm) extending in the longitudinal direction. By arranging the adhesive in this way, the body fluid that has passed through the top sheet is absorbed by the second sheet while diffusing in the longitudinal direction along the adhesive. Therefore, the diffusion of the body fluid in the width direction of the absorbent article can be suppressed, and the occurrence of lateral leakage can be further suppressed.

It is preferable that the second sheet is arranged at least below (back sheet side) of both end regions in the width direction of the top sheet. By arranging the second sheet below the area at both ends in the width direction of the top sheet, the body fluid that diffuses in the plane direction on the top sheet and reaches the vicinity of the end in the width direction is quickly absorbed by the second sheet and becomes an absorber. Can be migrated. Therefore, the occurrence of lateral leakage of body fluid can be further suppressed. The width direction both ends region of the top sheet is a range in which the distance from the width direction end portion is 0% to 30% when the width direction length of the top sheet is 100%. It is preferable that the second sheet is continuously arranged in the longitudinal direction of the absorbent article in both widthwise regions of the top sheet. In this case, the length of the second sheet in the longitudinal direction is preferably 70% or more, more preferably 80% or more, and preferably 100% or less, when the length in the longitudinal direction of the top sheet is 100%.

The second sheet preferably has an opening in at least a part of the central portion in the width direction. By having an opening in the central part in the width direction, the body fluid excreted on the top sheet is rapidly absorbed in the vicinity of the body fluid discharge part before being diffused in the plane direction, and the gel blocking phenomenon of the water-absorbent resin powder in this vicinity occurs. More suppressed. The gel blocking phenomenon is a phenomenon in which when the water-absorbent resin powder on the top sheet side absorbs the body fluid and swells, the voids as passages of the body fluid are closed and the absorber cannot exhibit a predetermined water absorption capacity. The width of the opening is preferably 10% or more, more preferably 20% or more, preferably 60% or less, more preferably 60% or less, assuming that the length in the width direction of the absorbent article in the portion where the opening exists is 100%. It is preferably 50% or less. The length of the opening is preferably 50% or more, more preferably 60%, when the length of the second sheet in the longitudinal direction of the portion where the opening is present is 100%. The two second sheets may be arranged apart from each other in the width direction, and a region in which the second sheet is not arranged may be provided in the central portion in the width direction of the absorbent article.

It is preferable that at least a part of the second sheet is in direct contact with the water absorption layer of the absorber. With such a configuration, the body fluid can be easily transferred from the second sheet to the water-absorbent resin powder in the water-absorbent layer.

5.2 Absorbent The plan-view shape of the absorber and the water-absorbing layer is not particularly limited, and examples thereof include a rectangular shape, an hourglass type, a gourd type, and a battledore type. The absorber may be one or two or more. In this case, the plan-view shapes of the respective absorbers may be the same or different.

It is preferable that the water absorption layer is arranged below (on the back sheet side) over the entire surface of the plan view shape of the second sheet. By arranging in this way, the body fluid that has passed through the second sheet is immediately absorbed by the absorber, and the leakage of the body fluid is further suppressed. When two or more absorbers are arranged, it is sufficient that at least one absorbent layer of the absorber is present below the second sheet in a plan view.

When a plurality of the absorbers are arranged in the thickness direction, it is preferable that the water absorption layer of the absorber arranged at the uppermost side (top sheet side) has an opening in at least a part of the central portion in the width direction. By having an opening in the central portion in the width direction, the body fluid that has passed through the second sheet is immediately transferred to the lower absorber through this opening. Therefore, the absorption rate of the absorbent article is further improved. The width of the opening is preferably 1% or more, more preferably 2% or more, preferably 30% or less, and more preferably 1% or more, assuming that the length of the water absorption layer in the width direction of the portion where the opening exists is 100%. It is preferably 20% or less. The length of the opening is preferably 30% or more, more preferably 40%, preferably 80% or less, and more preferably 80% or less, when the length of the water absorption layer in the portion where the opening exists in the longitudinal direction is 100%. It is preferably 70% or less.

6 Specific Examples Next, specific application examples of the absorbent article will be described. Examples of the absorbent article include an absorbent article used for absorbing body fluid discharged from the human body such as an incontinence pad, a disposable diaper, and a sanitary napkin.

When the absorbent article is an incontinence pad, a sanitary napkin, they have, for example, a second sheet and an absorber placed between the top sheet and the back sheet. Examples of the shape of the incontinence pad and the sanitary napkin include a substantially rectangular shape, an hourglass type, and a gourd type.

When the absorbent article is a disposable diaper, the disposable diaper is, for example, a tape-type disposable diaper in which a pair of fastening members are provided on the left and right sides of the back or front abdomen, and the fastening members form a pants shape when worn. Diapers; Pants-type disposable diapers in which a waist opening and a pair of leg openings are formed by joining the anterior abdomen and the back back; and the like.

When the absorbent article is a disposable diaper, the disposable diaper forms, for example, a diaper body consisting of a laminate of inner and outer sheets consisting of anterior abdomen and back and a crotch located between them. , A second sheet and an absorber may be arranged between the top sheet and the back sheet in the crotch portion. In addition, a disposable diaper is composed of, for example, a laminate in which a second sheet and an absorber are arranged between a top sheet and a back sheet, and this laminate is located in the anterior abdomen, the back back, and the crotch portion located between them. And may have. The front abdomen, back back, and crotch are referred to as the front abdomen when the disposable diaper is worn, and the part that hits the wearer's buttock side is called the back back. The part located between the abdomen and the back of the back and applied to the wearer's crotch is called the crotch. The inner sheet is preferably hydrophilic or water repellent, and the outer sheet is preferably water repellent.

It is preferable that the absorbent article is provided with rising flaps along both side edges of the absorber. The rising flaps may be provided, for example, on both side edges in the width direction of the upper surface of the absorber, or may be provided on both outer sides in the width direction of the absorber. By providing the rising flap, it is possible to prevent lateral leakage of excrement such as urine. The rising flaps may be formed by raising the inner ends of the side sheets provided on both sides of the top sheet in the width direction. The rising flap and side sheet are preferably water repellent.

Next, an example of the embodiment of the absorbent article will be described with reference to FIGS. 1 to 10 by taking an incontinence pad as an example. FIG. 1 represents a plan view of the incontinence pad of the first embodiment. FIG. 2 shows a VV cross-sectional view of the incontinence pad of FIG. FIG. 3 shows a plan view showing an arrangement mode of the adhesive of the incontinence pad of the first embodiment. FIG. 4 shows a plan view of the incontinence pad of the second embodiment. FIG. 5 shows a VV cross-sectional view of the incontinence pad of FIG. FIG. 6 shows a plan view of the incontinence pad of the third embodiment. FIG. 7 shows a VV cross-sectional view of the incontinence pad of FIG. FIG. 8 shows a plan view showing an arrangement mode of the adhesive of the incontinence pad of the third embodiment. FIG. 9 shows a plan view of the incontinence pad of the fourth embodiment. FIG. 10 shows a VV cross-sectional view of the incontinence pad of FIG. In the figure, the arrow B indicates the width direction, and the arrow A indicates the longitudinal direction. The direction on the plane formed by the arrows A and B is the plane direction. Further, in FIGS. 3 and 8, only the top sheet 2, the back sheet 3, the second sheet 4, and the adhesive 9 are shown.

Embodiment 1
The incontinence pad (absorbent article) 1 of the first embodiment shown in FIGS. 1 and 2 includes a liquid-permeable top sheet 2, a liquid-impermeable back sheet 3, and a second sheet 4 arranged between them. , Has an absorber 5.

In the incontinence pad 1, a rectangular second sheet 4 is arranged parallel to the longitudinal direction of the incontinence pad. Further, the second sheet 4 is continuously arranged in the longitudinal direction of the incontinence pad 1 in the widthwise both end regions of the top sheet 1. The second sheet 4 is bonded to the top sheet 1 with an adhesive. As shown in FIG. 3, the adhesive 9 arranged between the second sheet 4 and the top sheet 1 is arranged in a streak extending in the longitudinal direction of the incontinence pad. Further, the second sheet 4 is in direct contact with the top sheet 1 at a portion where the adhesive 9 is not arranged.

The incontinence pad 1 of the first embodiment has an absorber 5 as an absorber. The absorber 5 is composed of a first base material 52, a second base material 53, and a water absorption layer 51 arranged between them. The plan view shape of the water absorption layer 51 is larger than the plan view shape of the second sheet 4. Therefore, the water absorption layer is arranged on the back seat side over the entire surface of the second sheet 4 in a plan view.

Although FIGS. 1 and 2 show an example in which the absorber 5 having a gourd-shaped plan view is arranged as the absorber, the configuration of the absorber is not limited to this. In FIGS. 1 and 2, the absorber 5 is composed of a first base material 52, a second base material 53, and a water absorption layer 51 arranged between them, but the second base material 53 is not arranged. The second sheet 4 and the water absorption layer 51 may be brought into direct contact with each other.

Side sheets 7 extending in the longitudinal direction A of the incontinence pad 1 are joined to both side edges of the top sheet 2 in the width direction B. The side sheet 7 is made of a liquid-impermeable plastic film, a water-repellent non-woven fabric, or the like. The side seat 7 is provided with an upright elastic member 8 at the inner end in the width direction of the incontinence pad 1. When the incontinence pad 1 is used, the inner end of the side seat 7 rises toward the wearer's skin due to the contraction force of the standing elastic member 8, thereby preventing lateral leakage of excrement such as urine.

Embodiment 2
The second embodiment shown in FIGS. 4 and 5 has a different structure of the absorber from the first embodiment. The top sheet 2, the second sheet 4, the back sheet 3, the side sheet 7, the elastic member 8 for standing up, and the adhesive 9 are the same as those in the first embodiment, and thus the description thereof will be omitted. The incontinence pad (absorbent article) 1 of the second embodiment includes a liquid-permeable top sheet 2, a liquid-impermeable back sheet 3, a second sheet 4 arranged between them, a first absorbent body 5, and the like. It has a second absorber 6.

The incontinence pad 1 has a first absorber 5 and a second absorber 6 arranged on the back seat side of the first absorber 5 as an absorber. The first absorber 5 is composed of a first base material 52, a second base material 53, and a water absorption layer 51 arranged between them. The water absorption layer 51 has an opening 5a at the center in the width direction. The second absorber 6 is composed of a water absorption layer 61 and a base material 62 that encloses the water absorption layer 61. The water-absorbent layer 61 contains a water-absorbent resin powder and a fiber base material, and the content of the water-absorbent resin powder on the side surface of the second sheet of the water-absorbent layer 61 is higher than the content of the water-absorbent resin powder on the side surface of the back sheet. It's getting higher. Further, the water absorption layer 61 of the second absorber 6 is arranged below the opening 5a of the water absorption layer 51 of the first absorber 5. Therefore, the water absorption layer is arranged on the back seat side over the entire surface of the second sheet 4 in a plan view.

FIGS. 4 and 5 show an example in which two absorbers, a first absorber 5 having a gourd-shaped plan view and a second absorber 6 having a rectangular plan-view shape, are arranged as absorbers. , The composition of the absorber is not limited to this. Further, in FIGS. 4 and 5, the first absorber 5 has an opening 5a, but it does not have to have an opening. Further, in FIGS. 4 and 5, the first absorber 5 is composed of a first base material 52, a second base material 53, and a water absorption layer 51 arranged between them. The second sheet 4 and the water absorption layer 51 may be brought into direct contact with each other without being arranged.

Embodiment 3
The third embodiment shown in FIGS. 6 and 7 differs from the second embodiment in the configuration of the second seat. The top sheet 2, the back sheet 3, the first absorber 5, the second absorber 6, the side sheet 7, and the elastic member 8 for standing up are the same as those in the second embodiment, and thus the description thereof will be omitted. The incontinence pad (absorbent article) 1 of the third embodiment includes a liquid-permeable top sheet 2, a liquid-impermeable back sheet 3, a second sheet 4 arranged between them, a first absorbent body 5, and the like. It has a second absorber 6.

In the incontinence pad 1, the two second sheets 4 are arranged apart from each other in the width direction of the incontinence pad 1, and the second sheet is not arranged at the central portion in the width direction of the incontinence pad 1. Then, the area where the second sheet is not arranged becomes the opening of the second sheet 4. Further, the second sheet 4 is continuously arranged in the longitudinal direction of the incontinence pad 1 in the widthwise both end regions of the top sheet 1. The second sheet 4 is bonded to the top sheet 1 with an adhesive. As shown in FIG. 8, the adhesive 9 arranged between the second sheet 4 and the top sheet 1 is arranged in a streak extending in the longitudinal direction of the absorbent article. Further, the second sheet 4 is in direct contact with the top sheet 1 at a portion where the adhesive 9 is not arranged.

6 and 7 show an example in which two absorbers, a first absorber 5 having a gourd shape in a plan view and a second absorber 6 having a rectangular shape in a plan view, are arranged as absorbers. , The composition of the absorber is not limited to this. Further, in FIGS. 6 and 7, the first absorber 5 has an opening 5a, but it does not have to have an opening.

Embodiment 4
The fourth embodiment shown in FIGS. 9 and 10 has a different structure of the absorber from the third embodiment. The top sheet 2, the back sheet 3, the second sheet 4, the second absorber 6, the side sheet 7, the standing elastic member 8 and the adhesive 9 are the same as those in the third embodiment, and thus the description thereof will be omitted. .. The incontinence pad (absorbent article) 1 of the fourth embodiment includes a liquid-permeable top sheet 2, a liquid-impermeable back sheet 3, a second sheet 4 arranged between them, a first absorbent body 5, and the like. It has a second absorber 6.

The incontinence pad 1 has a first absorber 5 and a second absorber 6 arranged on the back seat side of the first absorber 5 as an absorber. The first absorbent body 5 is composed of a first base material 52 and a water absorbing layer 51 fixed to the first base material 52. The second sheet 4 is arranged so as to be in direct contact with the water absorption 51 of the first absorber 5. Further, the water absorption layer 51 has an opening 5a in the central portion in the width direction. The water absorption layer 61 of the second absorber 6 is arranged below the opening 5a of the water absorption layer 51 of the first absorber 5. Therefore, the water absorption layer is arranged on the back seat side over the entire surface of the second sheet 4 in a plan view.

9 and 10 show an example in which two absorbers, a first absorber 5 having a gourd-shaped plan view and a second absorber 6 having a rectangular plan-view shape, are arranged as the absorbers. , The composition of the absorber is not limited to this. In FIGS. 9 and 10, the first absorber 5 has an opening 5a, but it does not have to have an opening.

Hereinafter, the present invention will be described in detail with reference to Examples, but the present invention is not limited to the following Examples, and changes and embodiments within the scope of the present invention are all described in the present invention. Included within range.

[Evaluation method]
(Permeability rate)
Ion-exchanged water (0.5 mL) was added dropwise from a height of 5 cm from the second sheet. The moisture permeation rate was calculated by measuring the time from the time when the water droplets fell on the upper surface of the second sheet until the water droplets disappeared from the upper surface of the second sheet.

(The bulk density)
The bulk density is measured according to JIS K6219-2 (2005). The water-absorbent resin powder as a sample is poured into the center of a cylindrical container (stainless steel container having a diameter of 100 mm and a capacity of 1000 ml) having a known mass and capacity from a height of 50 mm or less from the upper end of the container. At this time, a sufficient amount of the 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, using a spatula, the excess sample above the upper end of the cylindrical container is wiped off, the mass of the container is measured in this state, and the mass of the container is subtracted from the measured value to obtain the mass of the sample. , Divide this by the capacity of the container to calculate the desired bulk density. 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 3 points was used as the measured value. These measurements are performed at 23 ± 2 ° C. and a relative humidity of 50 ± 5%, and the samples are stored in the same environment for 24 hours or more before the measurement.

(Water absorption rate by vortex method)
A 100 mL glass beaker with 50 mL of physiological saline (0.9 mass% 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 place the beaker on a magnetic stirrer (manufactured by AS ONE, "HPS-100"). The rotation speed of the magnetic stirrer is adjusted to 600 ± 60 rpm, and the saline solution is stirred. 2.0 g of the sample is put into the liquid at the center of the vortex of the saline solution during stirring, 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 put 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 (time point) and record the time (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 3 points was used as the measured value. These measurements are performed at 23 ± 2 ° C. and a relative humidity of 50 ± 5%, and the samples are stored in the same environment for 24 hours or more before the measurement.

(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 mass% sodium chloride solution) and allowed to stand for 60 minutes for swelling. Separately, at the lower end of the opening of a vertically erected cylinder (inner diameter 25.4 mm), a wire mesh (opening 150 μm, biocolumn sintered stainless steel filter 30SUS manufactured by Sansho Co., Ltd.) and a thin tube with a cock (inner diameter 2 mm) (inner diameter 2 mm) A filtration cylindrical tube having an inner diameter of 4 mm and a length of 8 cm) is prepared, and all 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 and having a wire mesh having a mesh size of 150 μm and a diameter of 25 mm at the tip is inserted into the filtration cylindrical tube so that the wire mesh and the measurement sample are in contact with each other, and the measurement sample is further charged with 2.0 kPa. Place the weight so that the load is applied. After leaving it in this state for 1 minute, the cock is opened to allow the liquid to flow, and the time from the 60 mL scale line to the 40 mL scale line (that is, 20 mL liquid passes) is T1 (seconds). ) Is measured. Using the measured time T1 (seconds), the underload liquid passing speed at 2.0 kPa is calculated from the following equation. In the formula, T0 (seconds) is a value obtained by measuring the time required for 20 ml of physiological saline to pass through the wire mesh without placing the measurement sample in the filtration cylindrical tube.
Liquid passing speed under load (seconds) = (T1-T0)
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 3 points was used 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 has been stored in the same environment for 24 hours or more before the measurement.

(Hygroscopic blocking rate)
10.0 g of the sample was 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 placed in a constant temperature and humidity chamber at 40 ° C. and a relative humidity of 80% RH for 3 hours. Let stand. After that, lightly sieve with a 12-mesh wire mesh (opening 1.4 mm), block by moisture absorption, and measure the mass of the powdered sample that does not pass 12 mesh and the mass of the sample that passed 12 mesh. The target moisture absorption blocking rate is calculated according to the above.
Moisture absorption blocking rate (%) = 100 x (mass of sample that does not pass 12 mesh after standing) / (mass of sample that does not pass 12 mesh after standing + mass of sample that passes 12 mesh after standing)
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 3 points was used as the measured value. The measurement is performed at 23 ± 2 ° C. and 50 ± 5% humidity, and the sample is stored in the same environment for 24 hours or more before the measurement.

(Absorption ratio)
The absorption ratio is measured in accordance with JIS K 7223 (1996). A nylon net with a mesh opening of 63 μm (JIS Z8801-1: 2000) 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) and a length. Make a 20 cm nylon bag. Weigh 1.00 g of the measurement sample and put it evenly on the bottom of the prepared nylon bag. Immerse the nylon bag containing the sample in physiological saline. After 60 minutes from the start of immersion, the nylon bag is taken out from the physiological saline solution, hung vertically for 1 hour to drain water, and then the mass F1 (g) 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 these masses F1, F0 and the mass of the sample, the target absorption magnification is calculated according to the following equation.
Absorption rate (g / g) = (F1-F0) / mass of sample

(Water retention amount)
The amount of water retained is measured in accordance with JIS K 7223 (1996). A nylon net with a mesh opening of 63 μm (JIS Z8801-1: 2000) 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) and a length. Make a 20 cm nylon bag. Weigh 1.00 g of the measurement sample and put it evenly on the bottom of the prepared nylon bag. Immerse the nylon bag containing the sample in physiological saline. 60 minutes after the start of immersion, the nylon bag is taken out of the physiological saline solution, hung vertically for 1 hour to drain water, and then dehydrated using a centrifugal dehydrator (manufactured by Kokusan Co., Ltd., model H-130C special type). The dehydration condition is 143 G (800 rpm) for 2 minutes. The mass R1 (g) after dehydration 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 and R0 and the mass of the sample, the target water retention amount is calculated according to the following equation.
Water retention (g / g) = (R1-R0-sample mass) / sample mass

[Preparation of second sheet]
From soft slab polyurethane foam (polyester polyurethane foam, trade name: Maltoprene, manufactured by Inoac Corporation, density 75 kg / m ³ , breathability 12 L / min, number of cells 64/25 mm), in the direction orthogonal to the foam direction A foam sheet (width 400 mm × length 400 mm × thickness 2 mm) was cut out. The foam sheet was subjected to heat compression molding. Heat compression molding is performed by compressing the required amount up and down along the thickness direction of the foam sheet by a hot plate attached to a hydraulic press type compression molding machine (maximum pressure 210 kg / cm ^{2, maximum mold clamping force 37 tons) to heat.} Press (hot plate temperature: 180 ° C., molding time: 4 minutes). The thickness of the foam sheet after heat compression molding was 2.5 mm.
Surfactant aqueous solution (surfactant type: polyoxyethylene lauryl ether, HLB 8.5) is applied to the surface of the foam sheet (apparent density 150 kg / m ^{3, breathability 12 L / min) after heat compression molding.} The mixture was sprayed so that the amount of the mixture applied was 0.001 g / m ^2, and dried to obtain a second sheet.

[Synthesis of water-absorbent resin powder]
<Synthesis example 1>
Water-soluble ethylenically unsaturated monomer (a1) {acrylic acid, manufactured by Mitsubishi Chemical Corporation, purity 100%} 155 parts by mass (2.15 mol parts), internal cross-linking agent (a2) {pentaerythritol triallyl ether, Daiso- Co., Ltd.} 0.6225 parts by mass (0.0024 mol parts) and 340.27 parts by mass of deionized water were kept at 1 ° C. while stirring and mixing. After influxing nitrogen into this mixture to reduce the amount of dissolved oxygen to 0.1 ppm or less, 0.31 parts by mass of a 1 mass% hydrogen peroxide aqueous solution and 1.1625 parts by mass of a 1 mass% ascorbic acid aqueous solution and 0.5 mass. 2.325 parts by mass of an aqueous solution of% 2,2'-azobis [2-methyl-N- (2-hydroxyethyl) -propionamide] was added and mixed to initiate polymerization. After the temperature of the mixture reached 85 ° C., a hydrogel (1) was obtained by polymerizing at 85 ± 2 ° C. for about 10 hours.

Next, 128.42 parts by mass of a 48.5% by mass sodium hydroxide aqueous solution was added while shredding 502.27 parts by mass of this hydrogel (1) with a mincing machine (manufactured by ROYAL, "12VR-400K"). And mixed, and 3 parts by mass of a 1% by mass aqueous solution of ethylene glycol diglycidyl ether was added and mixed to obtain a shredded gel (2). Further, the shredded gel (2) was dried with a ventilation type band dryer {200 ° C., wind speed 5 m / sec} to obtain a dried product. The dried product was pulverized with a juicer mixer (“OSTERIZER BLENDER” manufactured by Oster), and then adjusted to a particle size of 150 μm to 710 μm using a sieve having an opening of 150 μm and 710 μm to obtain dried product particles.

2% by mass water / methanol mixed solution of ethylene glycol diglycidyl ether (mass ratio of water / methanol =) while stirring 100 parts by mass of the dried body particles at high speed (manufactured by Hosokawa Micron, high-speed stirring turbulizer: rotation speed 2000 rpm). 5 parts by mass of 70/30) was added by spray spraying, mixed, and allowed to stand at 150 ° C. for 30 minutes for surface cross-linking to obtain a (A) cross-linked polymer. With respect to 100 parts by mass of this (A) crosslinked polymer, 0.5 parts by mass of silica (manufactured by Toshin Kasei Co., Ltd., "Aerosil 380") as a surface modifier (B) and carboxy-modified polysiloxane (Shin-Etsu Chemical Co., Ltd.) "X-22-3701E" manufactured by Kogyo Co., Ltd.) 0.02 parts by mass was added, and the mixture was stirred at 85 ° C. for 60 minutes. The mass average particle size of the obtained resin powder was adjusted to 400 μm to obtain a water-absorbent resin powder. The physical properties of the water-absorbent resin powder are as follows: bulk density is 0.45 g / ml, water absorption rate by vortex method is 24 seconds, liquid flow rate under load is 7 seconds, moisture absorption blocking rate is 1%, and water absorption ratio is 44 g / g. The water retention amount was 26 g / g, and the weight average particle size was 400 μm.

[Preparation of absorber]
A water-absorbent layer composed of pulp fibers and a water-absorbent resin powder was sandwiched between a first base material and a second base material to prepare a first absorber. A second absorber was prepared by wrapping a water-absorbent layer composed of pulp fibers and a water-absorbent resin powder with a base material.

[Making absorbent articles]
Absorbent article An absorbent article was prepared by laminating a liquid-permeable air-through non-woven fabric, a second sheet, a first absorbent body, a second absorbent body, and a liquid-impermeable polyethylene sheet in this order from the top.

1: Absorbent article 2: Top sheet 3: Back sheet 4: Second sheet 5: First absorber, 51: Water absorbing layer, 52: First base material, 53: Second base material, 6: No. 2 absorber, 61: absorbent layer, 7: side sheet, 8: elastic member for standing, 9: adhesive

Claims (9)

A liquid-permeable top sheet, a second sheet arranged on the outer surface side of the top sheet, an absorber arranged on the outer surface side of the second sheet, and an impermeable property arranged on the outer surface side of the absorber. With a backseat,
It said second sheet is made of polyurethane continuous porous body, an apparent density of ^{100kg / m 3 ~200kg / m 3} ,
The second sheet has an opening in at least a part of the central portion in the width direction of the absorbent article.
A plurality of the absorbers are arranged in the thickness direction, and the water absorption layer of the absorbers arranged on the top sheet side has an opening in at least a part of the central portion in the width direction.
The top sheet and the second sheet are joined by an adhesive, and the top sheet and the second sheet are joined by an adhesive.
An absorbent article characterized in that the adhesive is continuous in the longitudinal direction of the absorbent article and intermittently arranged in the width direction of the absorbent article. The absorbent article according to claim 1, wherein the absorber contains a water-absorbent resin powder that satisfies the following requirements (a) to (d).
(A) Bulk density: 0.50 g / ml to 0.70 g / ml
(B) Absorption rate by vortex method: 25 seconds to 75 seconds (c) Liquid flow rate under load: 40 seconds or less (d) Moisture absorption blocking rate: 5% or less The absorbent article according to claim 1 or 2, wherein the polyurethane continuous porous body has a hydrophilic skeleton surface. The absorbent article according to claim 3, wherein the polyurethane constituting the skeleton of the polyurethane continuous porous body contains a polyalkylene oxide polyol as a polyol component. The absorbent article according to claim 3, wherein the polyurethane continuous porous body is obtained by coating at least a part of the skeleton surface with a surfactant. The absorber has a water-absorbent layer containing a water-absorbent resin powder and a fiber base material, and has a water-absorbent layer.
The item according to any one of claims 1 to 5, wherein the content of the water-absorbent resin powder on the side surface of the second sheet of the water-absorbent layer is higher than the content of the water-absorbent resin powder on the side surface of the back sheet of the water-absorbent layer. Absorbent article. The claim that the adhesive is arranged in a streak extending in the longitudinal direction of the absorbent article, the width of each streak is 0.8 mm to 1.2 mm, and the distance between the streaks is 2.0 mm to 4.0 mm. The absorbent article according to any one of 1 to 6. The absorber has a water absorbing layer containing an absorbent resin powder, and has a water absorbing layer.
The absorbent article according to any one of claims 1 to 7, wherein at least a part of the second sheet is in direct contact with the water absorbing layer. The second sheet according to any one of claims 1 to 8, wherein the two second sheets are arranged apart from each other in the width direction, and the second sheet has a region in the central portion in the width direction of the absorbent article in which the second sheet is not arranged. Absorbent article.

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