JP6898842B2 - Absorbent resin particles, absorbers containing them and absorbent articles - Google Patents

Description

The present invention relates to absorbent resin particles, an absorber containing the absorbent resin particles, and an absorbent article.

Currently, for sanitary materials such as disposable diapers, sanitary napkins, and incontinence pads, as absorbents, hydrophilic fibers such as pulp and absorbent resins (SUPer Absorbent Polymer) whose main raw materials are acrylic acid (salt) and the like are abbreviated as SAP. The combination with) is widely used. From the viewpoint of improving QOL (Quality Of Life) in recent years, the demand for these sanitary materials has shifted to lighter and thinner ones, and along with this, it has become desired to reduce the amount of hydrophilic fibers used. .. Therefore, the SAP itself is required to play the role that the hydrophilic fiber has played in the absorber. For example, an important function of diapers is the diffusion of urine. In the conventional absorber, hydrophilic fibers occupy a large proportion of the absorber, and the diffusion of urine is uniformly promoted in the absorber regardless of the absorption rate performance of the absorbent resin, effectively utilizing the absorbent resin in the absorber. It has a structure that can be used. However, when the amount of hydrophilic fibers used in the absorber is reduced, the absorption rate of the absorbent resin is biased depending on the part of the absorber, and the absorber cannot be effectively used. It is easy to occur. Alternatively, problems such as a long time for the unabsorbed liquid to stay in the entire absorber are likely to occur.

Therefore, there are known absorbent resin particles that uniformly promote the diffusion of urine in the absorber even if the amount of hydrophilic fibers used is small by controlling the absorption rate of SAP. For example, there are absorbent resin particles (Patent Document 1) having a structure containing a hydrophobic substance inside the crosslinked polymer. Further, absorbent resin particles having improved powder fluidity and the like by adhering a hydrophobic substance to the surface of the crosslinked polymer are known (Patent Document 2).

However, with conventional absorbent resin particles and water absorbing agents, the absorption rate (hereinafter referred to as absorption rate pattern) with respect to the passage of time after contact with the liquid to be absorbed is not appropriate. Specifically, the conventional absorbent resin particles have an absorption rate pattern of (i) early fast, medium normal, late normal (above, the absorbent resin particles of Patent Document 1 above), (ii) early slow, medium normal. , There are absorbable resin particles of late ordinary (absorption resin particles of Patent Document 2 above).

When these absorbent resin particles are applied to an absorbent article (paper diaper, etc.), in the absorbent body used for the absorbent article, the absorption rate of the absorbent resin is biased depending on the part of the absorbent body, and the absorbent body is effective. It cannot be utilized for the purpose, and it is easy to generate a part where the liquid to be absorbed remains. Alternatively, problems such as a long time for the unabsorbed liquid to stay in the entire absorber are likely to occur.

Specifically, when the absorbent resin particles of (i) above are used, the liquid is rapidly absorbed at the initial stage after contact with the absorbent resin particles at the portion where the liquid to be absorbed comes into contact. However, when the absorbent resin particles absorb the liquid and swell to form a gel, the unabsorbed liquid diffuses in the absorbing body and prevents it from being absorbed, and as a result, the part where the absorbed liquid comes into contact is absorbed. The absorption rate of the sex resin particles is high, and the absorption rate of the absorbent resin particles is low in the peripheral portion, which causes a bias in the absorption rate. Then, the liquid that has not been absorbed is likely to remain in the portion where the absorbed liquid comes into contact.

On the other hand, when the absorbent resin particles of (ii) are used, the liquid is absorbed only gradually after contacting the absorbent resin particles at the site where the liquid to be absorbed comes into contact, and the liquid that is not absorbed moves into the absorbing body. As a result, the absorption rate of the absorbent resin particles tends to be the same at the portion where the absorbed liquid comes into contact with the portion and the peripheral portion. However, since the absorption rate is slow as a whole, the unabsorbed liquid stays for a long time in the entire absorber.
These absorbent resins have a problem that problems such as rash are likely to occur on the skin of the wearer who comes into contact with the part where the unabsorbed liquid remains or stays for a long time.

Further, there is also known an absorbent resin particle having an absorption rate pattern (iii), which is slow in the early stage, normal in the middle stage, and fast in the late stage by controlling the amount of hydrophobic substances on the surface and inside of the absorbent resin particles (Patent Document 3). This is known to diffuse the liquid throughout the diaper rather than the absorption rate patterns of (i) and (ii) above. However, in thin paper diapers having a high SAP ratio, since the amount of pulp for diffusing the liquid is small, it is necessary to diffuse the liquid in the SAP gel itself, which does not necessarily satisfy the diaper performance.

Japanese Unexamined Patent Publication No. 2005-097569 Japanese Unexamined Patent Publication No. 2004-261996 WO20100073658A1

An object of the present invention is an absorption rate pattern in which the absorption rate is slow at the initial stage, normal at the middle stage, and fast at the late stage, and the absorbent resin particles having high liquid permeability of the swelling gel and the thin paper diaper do not cause problems such as fogging. To provide sex goods.

That is, the present invention has a cross-linking weight of a monomer composition containing a water-soluble vinyl monomer (a1) and / or a vinyl monomer (a2) that becomes a water-soluble vinyl monomer (a1) by hydrolysis and an internal cross-linking agent (b). Absorbent resin particles containing the coalescence (A), and in the Demand Wetability test method, the time until the absorption amount per 1 g of the absorbent resin particles for physiological saline reaches 2 g (t1), and the absorption amount becomes 20 g. Absorbent resin particles having a time (t2) ratio (t2 / t1) of 2 to 20 and a gel bed transmittance of 40 polymers or more at 0 psi swelling pressure; absorption comprising the absorbent resin particles. A body, particularly an absorbent body containing the absorbent resin particles and a fibrous substance; an absorbent article provided with the absorbent body.

The present inventors have solved the above problems by using absorbent resin particles having a specific absorption rate pattern and high gel permeability. The absorbent resin particles of the present invention have a velocity pattern of slow absorption in the early stage, normal in the middle stage, and fast in the late stage, and have high gel permeability. Therefore, when the absorbent resin particles of the present invention are applied to a thin absorbent article (paper diaper, sanitary napkin, etc.), the absorption rate is less biased and excellent absorption performance (absorption amount and absorption rate) is exhibited. Fog is less likely to occur.

The water-soluble vinyl monomer (a1) in the present invention is not particularly limited, and is known (for example, at least one water-soluble substituent and an ethylenically unsaturated group disclosed in paragraphs 0007 to 0023 of Japanese Patent No. 3648553. (For example, anionic vinyl monomer, nonionic vinyl monomer, cationic vinyl monomer), anionic vinyl monomer disclosed in paragraphs 0009 to 0024 of JP-A-2003-165883, nonionic vinyl. At least selected from the group consisting of a monomer, a cationic vinyl monomer, a carboxy group, a sulfo group, a phosphono group, a hydroxyl group, a carbamoyl group, an amino group and an ammonio group disclosed in paragraphs 0041 to 0051 of JP-A-2005-75982. A vinyl monomer (a vinyl monomer having one type) or the like can be used.

The vinyl monomer (a2) (hereinafter, also referred to as hydrolyzable vinyl monomer (a2)) which becomes a water-soluble vinyl monomer (a2) by hydrolysis is not particularly limited and is known (for example, 0024 to 0024 to JP-A-3648553). A vinyl monomer having at least one hydrolyzable substituent that becomes a water-soluble substituent by hydrolysis disclosed in paragraph 0025, and at least one vinyl monomer disclosed in paragraphs 0052 to 0055 of JP-A-2005-75982. A vinyl monomer having a hydrolyzable substituent (a vinyl monomer having a 1,3-oxo-2-oxapropylene (-CO-O-CO-) group, an acyl group, a cyano group, etc.) can be used. The water-soluble vinyl monomer is a concept well known to those skilled in the art, but when expressed using numerical values, it means, for example, a vinyl monomer that dissolves at least 100 g in 100 g of water at 25 ° C. Hydrolysis is a concept well known to those skilled in the art, but more specifically, it means that it is hydrolyzed by the action of water and, if necessary, a catalyst (acid, base, etc.). The hydrolyzable vinyl monomer (a2) may be hydrolyzed during or after the polymerization, or both of them, but it is preferable after the polymerization from the viewpoint of the absorption performance of the obtained absorbent resin composition.

Of these, the water-soluble vinyl monomer (a1) is preferable from the viewpoint of absorption characteristics and the like. More preferably, it is an anionic vinyl monomer, more preferably a vinyl monomer having a carboxy (salt) group, a sulfo (salt) group, an amino group, a carbamoyl group, an ammonio group or a mono-, di- or tri-alkylammonio group. .. Among these, vinyl monomers having a carboxy (salt) group or a carbamoyl group are more preferable, (meth) acrylic acid (salt) and (meth) acrylamide are more preferable, and (meth) acrylic acid (salt) is particularly preferable. The most preferable is acrylic acid (salt).

The "carboxy (salt) group" means a "carboxy group" or a "carboxylate group", and the "sulfo (salt) group" means a "sulfo group" or a "sulfonate group". Further, (meth) acrylic acid (salt) means acrylic acid, acrylate, methacrylic acid or methacrylic acid, and (meth) acrylamide means acrylamide or methacrylamide. The salt includes an alkali metal (lithium, sodium, potassium, etc.) salt, an alkaline earth metal (magnesium, calcium, etc.) salt, an ammonium (NH ₄ ) salt, and the like. Of these salts, alkali metal salts and ammonium salts are preferable, and alkali metal salts are more preferable, and sodium salts are particularly preferable, from the viewpoint of absorption characteristics and the like.

When the monomer composition contains either a water-soluble vinyl monomer (a1) or a hydrolyzable vinyl monomer (a2) as a constituent component, one type may be used alone as a constituent component, and two or more types may be used alone, if necessary. May be used as a constituent component. The same applies to the case where the water-soluble vinyl monomer (a1) and the hydrolyzable vinyl monomer (a2) are used as constituents. When the water-soluble vinyl monomer (a1) and the hydrolyzable vinyl monomer (a2) are used as constituents, the molar ratio (a1 / a2) of these is preferably 75/25 to 99/1, more preferably 75/25 to 99/1. It is 85/15 to 95/5, particularly preferably 90/10 to 93/7, and most preferably 91/9 to 92/8. Within this range, the absorption performance is further improved.

In addition to the water-soluble vinyl monomer (a1) and the hydrolyzable vinyl monomer (a2), the monomer composition may contain other vinyl monomer (a3) copolymerizable with the water-soluble vinyl monomer (a1) and the hydrolyzable vinyl monomer (a2). it can. As the other vinyl monomer (a3), one type may be used alone, or two or more types may be used in combination.

The other copolymerizable vinyl monomer (a3) is not particularly limited, and is known (for example, a hydrophobic vinyl monomer disclosed in paragraphs 0028 to 0029 of Japanese Patent No. 3648553, JP-A-2003-165883. The hydrophobic vinyl monomer (vinyl monomer) disclosed in paragraph 0058 of JP-A-2005-75982 can be used, and the following vinyl monomers (i) to (iii) can be used.
(I) Aromatic ethylenic monomer having 8 to 30 carbon atoms Styrene such as styrene, α-methylstyrene, vinyltoluene and hydroxystyrene, halogen-substituted styrene such as vinylnaphthalene and dichlorostyrene and the like.
(Ii) Alkenes of aliphatic ethylene monomers having 2 to 20 carbon atoms [ethylene, propylene, butene, isobutylene, pentene, heptene, diisobutylene, octene, dodecene, octadecene, etc.]; and alkaziene [butadiene, isoprene, etc.] and the like.
(Iii) Alicyclic ethylene monomer having 5 to 15 carbon atoms Monoethylene unsaturated monomer [pinene, limonene, indene, etc.]; and polyethylene vinyl polymerizable monomer [cyclopentadiene, bicyclopentadiene, ethilidene norbornene, etc.] and the like.

The content (mol%) of the other vinyl monomer (a3) unit is based on the total number of moles of the water-soluble vinyl monomer (a1) unit and the hydrolyzable vinyl monomer (a2) unit from the viewpoint of absorption performance and the like. The content is preferably 0 to 5, more preferably 0 to 3, particularly preferably 0 to 2, particularly preferably 0 to 1.5, and the content of other vinyl monomer (a3) units is high from the viewpoint of absorption performance and the like. Most preferably, it is 0 mol%.

The internal cross-linking agent (b) is not particularly limited, and is known (for example, a cross-linking agent having two or more ethylenically unsaturated groups disclosed in paragraphs 0031 to 0034 of Japanese Patent No. 3648553, a water-soluble substituent and the like. A cross-linking agent having at least one reactive functional group and at least one ethylenically unsaturated group, a cross-linking agent having at least two functional groups capable of reacting with a water-soluble substituent, JP-A-2003-165883. A cross-linking agent having two or more ethylenically unsaturated groups, a cross-linking agent having an ethylenically unsaturated group and a reactive functional group, and two or more reactive substituents disclosed in paragraphs 0028 to 0031 of the publication. Crosslinking agents, crosslinkable vinyl monomers disclosed in paragraph 0059 of JP-A-2005-75982, crosslinkable vinyl monomers disclosed in paragraphs 0015 to 0016 of JP-A-2005-59559) are used. it can. Of these, from the viewpoint of absorption characteristics and the like, a cross-linking agent having two or more ethylenically unsaturated groups is preferable, and a poly (meth) allyl ether of a polyol having 2 to 10 carbon atoms is preferable, and a poly (meth) allyl ether of a polyol having 2 to 10 carbon atoms is particularly preferable. Nurate, triallyl isocyanurate, tetraallyloxyetane, trimethylolpropane diallyl ether and pentaerythritol triallyl ether, most preferably pentaerythritol triallyl ether.

As the content (% by weight) of the internal cross-linking agent (b) contained in the monomer composition, other vinyl monomers (a3) of the water-soluble vinyl monomer (a1) and the hydrolyzable vinyl monomer (a2) are also used. In this case, based on the total weight of (a1) to (a3), 0.05 to 0.7 is preferable, more preferably 0.1 to 0.6, and particularly preferably 0.15 to 0.5. is there. Within this range, the absorption characteristics are further improved.

Examples of the method for producing the crosslinked polymer (A) include known aqueous solution polymerization (adiabatic polymerization, thin film polymerization, spray polymerization, etc.; JP-A-55-133413, etc.) using the above-mentioned monomer composition. It can be produced in the same manner as known reverse phase suspension polymerization (Japanese Patent Laid-Open No. 54-30710, Japanese Patent Application Laid-Open No. 56-26909, Japanese Patent Application Laid-Open No. 1-5808, etc.). Of the polymerization methods, a solution polymerization method is preferable, and an aqueous solution polymerization method is particularly preferable because it is not necessary to use an organic solvent or the like and is advantageous in terms of production cost.

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 weight) of the organic solvent after distillation is preferably 0 to 10, more preferably 0 to 5, and particularly preferably 0 to 5, based on the weight of the crosslinked polymer (A). Is 0 to 3, most preferably 0 to 1. Within this range, the absorption performance of the absorbent resin particles becomes even better.

When water is contained in the solvent, the water content (% by weight) after distillation is preferably 0 to 20, more preferably 1 to 10, and particularly preferably 2 to 9, based on the weight of the crosslinked polymer (A). Most preferably, it is 3 to 8. Within this range, the absorption performance and the breakability of the crosslinked polymer (A) after drying are further improved.

A hydrogel composed of the crosslinked polymer (A) and water can be obtained by the aqueous solution polymerization method. The obtained hydrogel can be shredded and used 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 particularly preferably 1 mm to 1 cm. Within this range, the solvent (including water) described later can be easily distilled off, which is preferable.

Shredding can be performed by a known method, and can be shredded using a known shredding device (for example, a Beck's mill, a rubber chopper, a pharma mill, a minced machine, an impact crusher and a roll crusher). ..

The content and water content of the organic solvent are determined by an infrared moisture measuring device (JE400 manufactured by KETT Co., Ltd., etc .: 120 ± 5 ° C., 30 minutes, atmospheric humidity before heating 50 ± 10% RH, lamp specification 100 V, It is obtained from the weight loss of the measurement sample before and after heating when heated by 40 W).

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

When an acid group-containing monomer such as acrylic acid or methacrylic acid is used as the water-soluble vinyl monomer (a1), the hydrogel may be neutralized with a base. The degree of neutralization of the acid group is preferably 50 to 80 mol%. If the degree of neutralization is less than 50 mol%, the adhesiveness of the obtained hydrogel polymer may be high, and workability during production and use may be deteriorated. Further, the amount of water retention of the obtained water-absorbent resin particles may decrease. On the other hand, when the degree of neutralization exceeds 80%, the pH of the obtained resin becomes high, and there is a concern about the safety of the obtained resin on the human skin.
The neutralization may be carried out at any stage after the polymerization of the crosslinked polymer (A) in the production of the water-absorbent resin particles, and for example, a method of neutralizing in the state of a hydrogel is preferable. Illustrated.
As the base to be neutralized, alkali metal hydroxides such as sodium hydroxide and potassium hydroxide, and alkali metal carbonates such as sodium carbonate, sodium hydrogen carbonate and potassium carbonate can be usually used.

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

After the hydrous gel is dried to obtain a crosslinked polymer (A), it can be further pulverized. The crushing method is not particularly limited, and a known crushing device (for example, a hammer type crusher, an impact type crusher, a roll type crusher, a shet airflow type crusher) or the like can be used. After pulverization, the particle size can be further adjusted by sieving or the like if necessary.

When the particle size is adjusted by sieving, the weight average particle size (μm) of the crosslinked polymer (A) obtained after sieving is preferably 100 to 800, more preferably 200 to 700, and then preferably 200 to 700. Is 250 to 600, particularly preferably 300 to 500, and most preferably 350 to 450. Within this 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 m 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 draw a line connecting each point to obtain the particle size corresponding to the weight fraction of 50% by weight, and use this as the weight average particle diameter.

From the viewpoint of absorption performance, the content of the fine particles contained in the crosslinked polymer (A) is 106 μm or less (preferably 150 μm or less) contained in the crosslinked polymer (A). Based on the total weight of A), it is preferably 3% by weight or less, and more preferably 1% by weight or less. The content of the fine particles can be determined using the plot prepared when determining the weight average particle size described above.

The apparent density of the crosslinked polymer (A) (unit: g / ml; the same applies hereinafter) is preferably 0.54 to 0.70, more preferably 0.56 to 0.65, and particularly preferably 0.58 to 0.58. It is 0.60. Within this range, the absorption performance is further improved. The apparent density is measured at 25 ° C. in accordance with JIS K7365: 1999.

The shape of the crosslinked polymer (A) 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 crosslinked polymer (A) can be surface-crosslinked with the surface cross-linking agent (d), if necessary. Examples of the surface cross-linking agent (d) are known {Japanese Patent Laid-Open No. 59-189103, JP-A-58-180233, JP-A-61-16903, JP-A-61-221305, JP-A. Surface cross-linking agents of Japanese Patent Application Laid-Open No. 61-252212, JP-A-51-136588, JP-A-61-257235, etc.} {Multivalent glycidyl, polyhydric alcohol, polyvalent amine, polyvalent aziridine, polyhydric isocyanate, Silane coupling agents, polyvalent metals, etc.} can be used. Of these, polyhydric glycidyl, polyhydric alcohols and polyhydric amines are preferable from the viewpoint of economy and absorption characteristics, more preferably polyhydric glycidyl and polyhydric alcohols, particularly preferably polyhydric glycidyl, and most preferably ethylene glycol. Diglycidyl ether.

The amount (% by weight) of the surface cross-linking agent (d) used can be variously changed depending on the type of the surface cross-linking agent (d), the conditions for cross-linking, the target performance, and the like. From the viewpoint and the like, it is preferably 0.03 to 0.5, more preferably 0.05 to 0.3, and particularly preferably 0.08 to 0.2, based on the total weight of the crosslinked polymer (A). ..

The step of surface cross-linking can be carried out by mixing the cross-linked polymer (A) and the surface cross-linking agent (d) and further heating, and is known (for example, Japanese Patent No. 36485553, Japanese Patent Application Laid-Open No. 2003-165883). The surface cross-linking treatment method described in JP-A, JP-A-2005-75982 and JP-A-2005-59559) can be used.

As a preferred method for surface cross-linking, an aqueous solution of the surface cross-linking agent (d) is sprayed on the surface of the cross-linked polymer (A) while stirring the cross-linked polymer (A), and then the mixture is stirred or allowed to stand. Examples thereof include a method of heating to 100 to 200 ° C. (preferably 120 ° C. to 160 ° C.) in the state. When an aqueous solution of the surface cross-linking agent (d) is sprayed on the surface of the cross-linked polymer (A), the concentration of the surface cross-linking agent (d) contained in the sprayed aqueous solution should be adjusted according to the type of the surface cross-linking agent (d). However, from the viewpoint of absorption characteristics and the like, it is preferably 0.1 to 10% by weight. The amount of the aqueous solution to be sprayed is preferably 0.5 to 15% by weight based on the weight of the crosslinked polymer (A) from the viewpoint of the uniformity of surface crosslinking. Among the steps of surface cross-linking, spraying an aqueous solution of the surface cross-linking agent (d) on the cross-linked polymer (A) under stirring is a known fluid-type humidifying and mixing granulator [Flexomix (manufactured by Hosokawa Micron) and Sugiflexomix (manufactured by Paulek Co., Ltd.)] and a known powder mixer [V-type mixer, Henschel mixer and turbulizer (manufactured by Hosokawa Micron Co., Ltd.), etc.] equipped with a known spraying device. Etc. can be used.

Among the steps of surface cross-linking, heating to 100 to 200 ° C. in a stirred state is a method of heating the cross-linked polymer (A) sprayed with a surface cross-linking agent to a known stirring device (double arm type kneader or the like) to which a heating device is attached. ) Can be used to stir while heating. Among the steps of surface cross-linking, heating to 100 to 200 ° C. in a stationary state can be performed using a known heating / drying device (circulation dryer or the like). When heating to 100 to 200 ° C., the heating time is usually 3 to 60 minutes, preferably 10 to 40 minutes.

As a method of mixing the cross-linked polymer (A) and the surface cross-linking agent (d), in addition to the method of spraying an aqueous solution of the surface cross-linking agent (d), the cross-linked polymer (A) is used as a surface cross-linking agent (d). ) Can also be used. When the cross-linked polymer (A) is immersed in an aqueous solution of the surface cross-linking agent (d), surface cross-linking can be performed by a method of heating with stirring thereafter.

The absorbent resin particles of the present invention preferably further contain a hydrophobic substance (C1) from the viewpoint of the specific and appropriate absorption rate pattern.

The hydrophobic substance (C1) includes a long chain (8 to 30 carbon atoms) fatty acid ester, a long chain (8 to 30 carbon atoms) fatty acid and a salt thereof, a long chain (8 to 30 carbon atoms) aliphatic alcohol, and a long chain. (8 to 30 carbon atoms) Aliphatic group-containing amides and mixtures of two or more of these are included.

As a long-chain (8 to 30 carbon atoms) fatty acid ester, an ester of a fatty acid having 8 to 30 carbon atoms and an alcohol having 1 to 12 carbon atoms {for example, methyl laurate, ethyl laurate, methyl stearate, ethyl stearate , Methyl oleate, ethyl oleate, glycerin lauric acid monoester, glycerin stearate monoester, glycerin oleic acid monoester, pentaerythlit lauric acid monoester, pentaerythlit lauric acid monoester, pentaerythlit oleic acid monoester , Solbit lauric acid monoester, sorbit stearic acid monoester, sorbit oleic acid monoester, sucrose palmitic acid monoester, sucrose palmitic acid diester, sucrose palmitic acid triester, sucrose stearic acid monoester, sucrose stearic acid Diester, sucrose stearic acid triester, beef fat, etc.}.

Examples of long-chain (8 to 30 carbon atoms) fatty acids and salts thereof include fatty acids having 8 to 30 carbon atoms {for example, lauric acid, palmitic acid, stearic acid, oleic acid, dimer acid, behenic acid, etc.}. As the salt, a salt with zinc, calcium, magnesium or aluminum (hereinafter abbreviated as Zn, Ca, Mg, Al) {for example, Ca palmitic acid, Al palmitic acid, Ca stearate, Mg stearate, Al stearate, etc.} Can be mentioned.

Examples of the long-chain (8 to 30 carbon atoms) fatty alcohol include aliphatic alcohols having 8 to 30 carbon atoms {for example, lauryl alcohol, palmityl alcohol, stearyl alcohol, oleyl alcohol, etc.}. From the viewpoint of leakage resistance of the absorbent article, palmityl alcohol, stearyl alcohol, and oleyl alcohol are preferable, and stearyl alcohol is more preferable.

The long-chain (8 to 30 carbon atoms) aliphatic group-containing amide includes an amidate of an aliphatic primary amine having 8 to 30 carbon atoms and a carboxylic acid having a hydrocarbon group having 1 to 30 carbon atoms, ammonia or carbon atoms. An amidate of a primary amine of 1 to 7 and a fatty acid having 8 to 30 carbon atoms, an aliphatic secondary amine having at least one aliphatic chain having 8 to 30 carbon atoms and a carboxylic acid having 1 to 30 carbon atoms. Examples thereof include aliphatic group-containing amides having 8 to 30 carbon atoms, such as amidates and amidates of secondary amines having two aliphatic hydrocarbon groups having 1 to 7 carbon atoms and fatty acids having 8 to 30 carbon atoms.
As an amidate of an aliphatic primary amine having 8 to 30 carbon atoms and a carboxylic acid having a hydrocarbon group having 1 to 30 carbon atoms, a 1: 2 reaction between a primary amine and a carboxylic acid and 1: 2 It is divided into those that reacted with. Examples of the 1: 1 reaction include N-octylamide acetate, N-hexacosylamide acetate, N-octylamide heptacosanoic acid, N-hexacosylamide heptacosanoic acid and the like. Examples of the 1: 2 reaction include N-octylamide diacetate, N-hexacosylamide diacetate, N-octylamide diheptacosanoic acid, and N-hexacosylamide diheptacosanoic acid. When the primary amine and the carboxylic acid are reacted at a ratio of 1: 2, the carboxylic acid used may be the same or different.

As an amidate of ammonia or a primary amine having 1 to 7 carbon atoms and a fatty acid having 8 to 30 carbon atoms, a reaction of ammonia or a primary amine and a carboxylic acid in a ratio of 1: 1 was reacted in a ratio of 1: 2. Divided into things. The 1: 1 reaction products include nonanoic acid amide, nonanoic acid methylamide, nonanoic acid N-heptylamide, heptacosanoic acid amide, heptacosanoic acid N-methylamide, heptacosanoic acid N-heptylamide and heptacosanoic acid N-hexacosylamide. And so on. Those that reacted 1: 2 include dinonanoic acid amide, dinonanoic acid N-methylamide, dinonanoic acid N-heptylamide, dioctadecanoic acid amide, dioctadecanic acid N-ethylamide, dioctadecanic acid N-heptylamide, and diheptacosanoic acid amide. , Diheptacosanoic acid N-methylamide, diheptacosanoic acid N-heptylamide, diheptacosanoic acid N-hexacosylamide and the like. The carboxylic acid used may be the same or different as a product obtained by reacting ammonia or a primary amine with a carboxylic acid at a ratio of 1: 2.

Examples of the amidate of the aliphatic secondary amine having at least one aliphatic chain having 8 to 30 carbon atoms and the carboxylic acid having 1 to 30 carbon atoms include N-methyloctylamide acetate and N-methylhexacosylamide acetate. , N-octylhexacylamide acetate, N-dihexacosylamide acetate, N-methyloctylamide heptacosanoic acid, N-methylhexacosylamide heptacosanoic acid, N-octylhexacosylamide heptacosanoic acid and N heptacosanoic acid. -Dihexacosylamide and the like.

The HLB value of the hydrophobic substance (C1) is preferably 1 to 10, more preferably 2 to 8, and particularly preferably 3 to 7. Within this range, the leakage resistance of the absorbent article becomes even better. The HLB value means a hydrophilic-lipophilic balance (HLB) value, and is obtained by the Oda method (Introduction to New Surfactants, p. 197, Takehiko Fujimoto, published by Sanyo Chemical Industries, Ltd., published in 1981). ..

From the viewpoint of leakage resistance of absorbent articles among hydrophobic substances (C1), sorbit stearic acid ester, sucrose stearic acid ester, stearic acid, Mg stearate, Ca stearate, Zn stearate and Al stearate, in particular. Sucrose stearic acid ester and Mg stearate are preferable, and sucrose stearic acid monoester is most preferable.

The hydrophobic substance (C1) may be present at any position of the absorbent resin particles, for example, may be present on the surface of the absorbent resin particles, or may be present inside the absorbent resin particles. It may be present inside and on the surface of the absorbent resin particles. It is preferably present at least inside the absorbent resin particles. Most of the hydrophobic substances (C1) are preferably present inside the absorbent resin particles, but some of them may be present on the surface. The content (% by weight) of the hydrophobic substance (C1) existing inside the absorbent resin particles is the content (% by weight) of the crosslinked polymer (A) from the viewpoint of the fogging resistance of the absorbent article and the leakage resistance of the absorbent article. Based on weight, it is usually 0.01 to 10.0% by weight, preferably 0.01 to 5.0, more preferably 0.05 to 2.0, and particularly preferably 0.1 to 1.0. Is.
The content (% by weight) of the hydrophobic substance (C1) present on the surface of the absorbent resin particles is the content (% by weight) of the crosslinked polymer (A) from the viewpoint of the fogging resistance of the absorbent article and the leakage resistance of the absorbent article. Based on weight, it is usually 0.001 to 1.0, preferably 0.005 to 0.5, more preferably 0.01 to 0.3, and particularly preferably 0.01 to 0.1. ..

The structure in which the hydrophobic substance (C1) is present inside the absorbent resin particles and a part is present on the surface is such that the absorbent resin particles are contained in water (1) the hydrophobic substance (C1) and the crosslinked polymer (A). It can be produced by a method of mixing and kneading with a gel, or (2) a method of polymerizing a constituent unit in the presence of a hydrophobic substance (C1) to obtain a water-containing gel of a crosslinked polymer (A).

In the method (1), as the shape of the hydrophobic substance (C1), a pulverized product, beads, rod-shaped or fibrous processed one can be used. From the viewpoint of leakage resistance of the absorbent article, pulverized products or beads are preferable, and beads are more preferable. The volume average particle size (μm) of the hydrophobic substance (C1) is preferably 0.5 to 100, more preferably 1 to 30, and particularly preferably 2 to 20.

The method for mixing the crosslinked polymer (A) and the hydrophobic substance (C1) is not limited as long as the hydrophobic substance (C1) is mixed so as to be present at least inside the crosslinked polymer (A). However, the hydrophobic substance (C1) is preferably mixed with the hydrogel of (A) or the polymer solution of (A), not the dried product of the crosslinked polymer (A), and more preferably of (A). It is to be mixed with a hydrous gel. It is preferable that the mixture is uniformly mixed so as to be kneaded.
When the crosslinked polymer (A) is obtained by the aqueous solution polymerization method, the timing of mixing and kneading the hydrophobic substances (C1) and (A) is not particularly limited, but during the polymerization step {in the presence of {(C1). , (A) is produced}, immediately after the polymerization step, during crushing (mincing) of the hydrous gel, during drying of the hydrogel, and the like. Of these, from the viewpoint of leakage resistance of the absorbent article, it is preferable immediately after the polymerization step and during the crushing (mincing) step of the hydrogel, and more preferably during the crushing (mincing) step of the hydrogel. When the hydrophobic substance (C1) is a long-chain fatty acid salt, the long-chain fatty acid salt itself is usually used, but a long-chain fatty acid and a metal hydroxide may be mixed in this addition step. You may put them individually.

When the crosslinked polymer (A) is obtained by the reverse phase suspension polymerization method or emulsion polymerization, the timing of mixing the hydrophobic substances (C1) and (A) is not particularly limited, but during the polymerization step {(C1) (A) is produced in the presence of}, immediately after the polymerization step, during the dehydration step (during the step of dehydrating to about 10% by weight of water content), immediately after the dehydration step, during the step of separating and distilling off the organic solvent used for the polymerization. , Drying of hydrogel, etc. Of these, from the viewpoint of leakage resistance of the absorbent article, it is preferable, more preferably, during the polymerization step, immediately after the polymerization step, during the dehydration step, immediately after the dehydration step, and during the step of separating and distilling off the organic solvent used for the polymerization. Is during the polymerization step and immediately after the polymerization step.

When mixing during crushing or drying of the hydrogel, known devices such as a Beck's mill, a rubber chopper, a pharma mill, a minced machine, an impact type crusher and a roll type crusher can be used as the mixing device. When mixing in a polymer solution, a device having a relatively high stirring power such as a homomixer or a biomixer can be used. Further, when mixing while drying the hydrogel, a kneading device such as an SV mixer can also be used.

The mixing temperature (° C.) can be appropriately adjusted by the step of adding (C1). For example, the mixing temperature (° C.) when added / mixed immediately after the polymerization step and during the crushing (mincing) step of the hydrogel is preferably 20 to 100, more preferably 40 to 90, and particularly preferably 50 to 80. .. Within this range, uniform mixing becomes easier, and the absorption characteristics become even better.

In the method (2) for producing the crosslinked polymer (A) in the presence of the hydrophobic substance (C1), the hydrophobic substance (C1) is uniformly dissolved or emulsified in the polymer solution of the crosslinked polymer (A) ( It is preferable to disperse). If the hydrophobic substance (C1) is difficult to be uniform, it can be further made uniform during the crushing step of the hydrogel. It can be carried out while precipitating (C1) as the polymerization of (A) progresses. The polymerization method is the same as that of the crosslinked polymer (A) except that the polymerization is carried out in the presence of the hydrophobic substance (C1).

The absorbent resin particles of the present invention preferably further contain a hydrophobic substance (C2) from the viewpoint of liquid permeability of the swelling gel.

Organic polysiloxane is used as the hydrophobic substance (C2), and polydimethylsiloxane, polyether-modified polysiloxane {polyoxyethylene-modified polysiloxane and poly (oxyethylene / oxypropylene) -modified polysiloxane, etc.}, carboxy-modified polysiloxane , Epoxy-modified polysiloxane, amino-modified polysiloxane, alkoxy-modified polysiloxane and the like, and organic polysiloxanes such as mixtures thereof.

The position of the organic group (modifying group) of the modified silicone {polyether-modified polysiloxane, carboxy-modified polysiloxane, epoxy-modified polysiloxane, amino-modified polysiloxane, etc.} is not particularly limited, but is a side chain of polysiloxane, polysiloxane. It may be either both ends of, one end of polysiloxane, or both side chains and both ends of polysiloxane. Of these, from the viewpoint of absorption characteristics and the like, 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 polyoxyethylene group, a group containing a poly (oxyethylene / oxypropylene) group, and the like. The content (pieces) of the oxyethylene group and / or the oxypropylene group contained in the polyether-modified polysiloxane is preferably 2 to 40, more preferably 5 to 30, and particularly preferably 5 to 30 per molecule of the polyether-modified polysiloxane. 7 to 20, most preferably 10 to 15. Within this range, the absorption characteristics are further improved. When an oxyethylene group and an oxypropylene group are contained, the content (% by weight) of the oxyethylene group is preferably 1 to 30, more preferably 3 to 25, and particularly preferably 5 based on the weight of the polysiloxane. ~ 20. Within this range, the absorption characteristics are further improved.

The polyether-modified polysiloxane is easily available on the market, and for example, the following products {modified position, type of oxyalkylene} can be preferably exemplified.
-KF-945 {side chain, oxyethylene and oxypropylene}, KF-6020 {side chain, oxyethylene and oxypropylene}, X-22-6191 {side chain, oxyethylene and oxypropylene} manufactured by Shin-Etsu Chemical Industry Co., Ltd. , X-22-4952 {side chain, oxyethylene and oxypropylene}, X-22-4272 {side chain, oxyethylene and oxypropylene}, X-22-6266 {side chain, oxyethylene and oxypropylene}
FZ-2110 {both ends, oxyethylene and oxypropylene}, FZ-2122 {both ends, oxyethylene and oxypropylene}, FZ-7006 {both ends, oxyethylene and oxypropylene}, manufactured by Toray Dow Corning Co., Ltd. FZ-2166 {both ends, oxyethylene and oxypropylene}, FZ-2164 {both ends, oxyethylene and oxypropylene}, FZ-2154 {both ends, oxyethylene and oxypropylene}, FZ-2203 {both ends, oxy Ethylene and oxypropylene} and FZ-2207 {both ends, oxyethylene and oxypropylene}

The organic group (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-order 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, and particularly 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 in accordance with JIS K2501: 2003 "8. Potentiometric titration method (base value / hydrochloric acid method)".

The carboxy-modified polysiloxane is easily available on the market, and for example, the following products {modified position, carboxy equivalent (g / mol)} can be preferably exemplified.
-Shin-Etsu Chemical Co., Ltd. X-22-3701E {side chain 4000}, X-22-162C {both ends 2300}, X-22-3710 {one end, 1450}
・ Toray Dow Corning Co., Ltd. BY 16-880 {side chain, 3500}, BY 16-750 {both ends, 750}, BY 16-840 {side chain, 3500}, SF8418 {side chain, 3500}

Epoxy-modified polysiloxanes are readily available on the market, and for example, the following products {modified position, epoxy equivalent} can be preferably exemplified.
-Shinetsu Chemical Industry Co., Ltd. X-22-343 {side chain, 525}, KF-101 {side chain, 350}, KF-1001 {side chain, 3500}, X-22-2000 {side chain, 620} , X-22-2046 {side chain, 600}, KF-102 {side chain, 3600}, X-22-4741 {side chain, 2500}, KF-1002 {side chain, 4300}, X-22-3000T {Side chain, 250}, X-22-163 {both ends, 200}, KF-105 {both ends, 490}, X-22-163A {both ends, 1000}, X-22-163B {both ends, 1750}, X-22-163C {both ends 2700}, X-22-169AS {both ends, 500}, X-22-169B {both ends 1700}, X-22-173DX {one end, 4500} , X-22-9002 {side chain, both ends, 5000}
FZ-3720 {side chain 1200}, BY 16-839 {side chain 3700}, SF 8411 {side chain 3200}, SF 8413 {side chain 3800}, SF 8421 {manufactured by Toray Dow Corning Co., Ltd. Side Chain 11000}, BY 16-876 {Side Chain 2800}, FZ-3736 {Side Chain 5000}, BY 16-855D {Side Chain, 180}, BY 16-8 {Side Chain, 3700}

Amino-modified silicones are readily available on the market, and for example, the following products {modified position, amino equivalent} can be preferably exemplified.
-KF-865 {side chain 5000}, KF-864 {side chain 3800}, KF-859 {side chain, 6000}, KF-393 {side chain, 350}, KF-860 manufactured by Shin-Etsu Chemical Industry Co., Ltd. {Side chain, 7600}, KF-880 {Side chain 1800}, KF-8004 {Side chain 1500}, KF-8002 {Side chain 1700}, KF-8005 {Side chain 11000}, KF-867 {Side chain, 1700}, X-22-3820W {Side chain, 55000}, KF-869 {Side chain, 8800}, KF-861 {Side chain, 2000}, X-22-3939A {Side chain, 1500} , KF-877 {side chain, 5200}, PAM-E {both ends, 130}, KF-8010 {both ends, 430}, X-22-161A {both ends, 800}, X-22-161B {both Ends 1500}, KF-8012 {both ends 2200}, KF-8008 {both ends 5700}, X-22-1660B-3 {both ends 2200}, KF-857 {side chains, 2200}, KF −8001 {side chain, 1900}, KF-862 {side chain, 1900}, X-22-9192 {side chain, 6500}
-Toray Dow Corning Co., Ltd. FZ-3707 {side chain 1500}, FZ-3504 {side chain, 1000}, BY 16-205 {side chain 4000}, FZ-3760 {side chain 1500}, FZ -3705 {side chain 4000}, BY 16-209 {side chain 1800}, FZ-3710 {side chain 1800}, SF 8417 {side chain 1800}, BY 16-849 {side chain, 600}, BY 16-850 {side chain, 3300}, BY 16-879B {side chain, 8000}, BY 16-892 {side chain, 2000}, FZ-3501 {side chain, 3000}, FZ-3785 {side chain, 6000}, BY 16-872 {side chain 1800}, BY 16-213 {side chain 2700}, BY 16-203 {side chain 1900}, BY 16-898 {side chain 2900}, BY 16- 890 {side chain, 1900}, BY 16-893 {side chain 4000}, FZ-3789 {side chain, 1900}, BY 16-871 {both ends, 130}, BY 16-853C {both ends 360} , BY 16-853U {both ends, 450}
Examples of these mixtures include a mixture of polydimethylsiloxane and carboxyl-modified polysiloxane, a mixture of polyether-modified polysiloxane and amino-modified polysiloxane, and the like.

The viscosity (mPa · s, 25 ° C.) of the hydrophobic substance (C2) is preferably 10 to 5000, more preferably 15 to 3000, and particularly preferably 20 to 1500. Within this range, the absorption characteristics are further improved. The viscosity is defined in JIS Z8803-1991 “Liquid Viscosity” 9. Conical and Conical-Measured according to the viscosity measurement method using a flat plate type rotational viscometer {For example, an E-type viscometer whose temperature is adjusted to 25.0 ± 0.5 ° C (RE80L manufactured by Toki Sangyo Co., Ltd., radius 7 mm) It is measured using a conical cone) angle 5.24 × ¹⁰ -2 rad. }

The hydrophobic substance (C2) is preferably present on the surface of the absorbent resin particles. The content (% by weight) of the hydrophobic substance (C2) present on the surface of the absorbent resin particles is the content (% by weight) of the crosslinked polymer (A) from the viewpoint of the fogging resistance of the absorbent article and the leakage resistance of the absorbent article. Based on weight, it is usually 0.001 to 1.0, preferably 0.005 to 0.1, and even more preferably 0.01 to 0.05.

The structure in which the hydrophobic substance (C2) is present on the surface of the absorbent resin particles can be produced by a method of mixing the absorbent resin particles with a powder of the hydrophobic substance (C2) and the crosslinked polymer (A). .. According to this production method, the hydrophobic substance (C2) is usually present substantially only on the surface of the absorbent resin particles.

The method for mixing the crosslinked polymer (A) and the hydrophobic substance (C2) is not limited as long as the hydrophobic substance (C2) is mixed so as to be present on the surface of the crosslinked polymer (A). The timing of mixing and kneading the hydrophobic substance (C2) and the crosslinked polymer (A) is not particularly limited, and examples thereof include a surface crosslinking step after drying the hydrogel and post-treatment after surface crosslinking. Of these, from the viewpoint of leakage resistance of the absorbent article, it is preferable during the surface cross-linking step. When the hydrophobic substance (C2) is a hydrophobic substance having a polysiloxane structure with a modified functional group, one type of modified product may be added, or a plurality of types of modified products may be added in combination. ..

In the resin particles of the present invention, the hydrophobic substance present on the surface may generally be only (C1) or only (C2) when (C2) is used in combination. Since a part of the added (C1) can be bleeded out to the surface, (C1) and (C2) may be present on the surface when (C1) and (C2) are used in combination. The total content (% by weight) of (C1) and (C2) present on the surface is preferably 0.001 to 1.0 based on the weight of the crosslinked polymer (A). The content of (C1) + (C2) is measured by the following method. The content of the hydrophobic substance (C1) existing inside shall be obtained by subtracting the content of the hydrophobic substance on the surface from the total amount of the hydrophobic substances added.

<Measurement method of the content of surface hydrophobic substances (C1) + (C2)>
100 parts by weight of absorbent resin particles and 300 parts by weight of n-hexane are added to a glass eggplant flask provided with a cooling tube, and the mixture is left at a dissolution temperature for 24 hours to obtain an extract of a hydrophobic substance. This extract is filtered using filter paper, collected in a pre-weighed glass eggplant flask, and the solvent is evaporated by a rotary evaporator before weighing. The amount of the evaporated dry matter extracted is obtained by subtracting the weight of the eggplant flask weighed in advance from the weight after evaporation of the filtrate.
Using the extracted sample remaining on the filter paper, the same operation was repeated twice, and the total amount of the evaporated dry matter obtained by the three extractions was calculated as the surface hydrophobic substances (C1) and (C2). The content (% by weight).

The absorbent resin particles of the present invention may further contain a polyvalent metal salt (e). By containing the polyvalent metal salt (e), the blocking resistance and liquid permeability of the absorbent resin particles are improved. Examples of the polyvalent metal salt (e) include salts of at least one metal selected from the group consisting of magnesium, calcium, zirconium, aluminum and titanium and the above-mentioned inorganic acid or organic acid.
As the polyvalent metal salt (e), an inorganic acid salt of aluminum and an inorganic acid salt of titanium are preferable from the viewpoint of availability and solubility, and aluminum sulfate, aluminum chloride, potassium aluminum sulfate and sulfate are more preferable. Sodium aluminum, particularly preferably aluminum sulphate and sodium aluminum sulphate, most preferably sodium sulphate. One of these may be used alone, or two or more thereof may be used in combination.

The content (% by weight) of the polyvalent metal salt (e) is preferably 0.05 to 5, more preferably 0.1 to 5 with respect to 100 parts by weight of the absorbent resin from the viewpoint of absorption performance and blocking resistance. 3, particularly preferably 0.2 to 2.

When the absorbent resin particles of the present invention contain a polyvalent metal salt (e), the steps of mixing with the polyvalent metal salt (e) are performed before the above-mentioned surface cross-linking step, after the surface cross-linking step, and on the surface. It can be performed at the same time as the step of cross-linking.

As a mixing method of the polyvalent metal salt (e), a cylindrical mixer, a screw type mixer, a screw type extruder, a turbulizer, a Nauter type mixer, a double arm type kneader, a fluid type mixer, and a V type mixing are used. Examples thereof include a method of uniformly mixing using a known mixing device such as a machine, a minced mixer, a ribbon type mixer, a flow type mixer, an air flow type mixer, a rotary disk type mixer, a conical blender and a roll mixer.
When mixing before or after the step of surface cross-linking, the temperature at the time of mixing is not particularly limited, but is preferably 10 to 150 ° C, more preferably 20 to 100 ° C, and particularly preferably 25 to 80 ° C.
When mixing at the same time as the step of surface cross-linking, the temperature at the time of mixing is not particularly limited, but the same conditions as the step of surface cross-linking with the surface cross-linking agent (d) can be performed.
After performing the step of mixing with the polyvalent metal salt (e), the particle size may be further adjusted.

The absorbent resin particles of the present invention may further contain water-insoluble inorganic particles (f). By mixing the water-insoluble inorganic particles (f), the surface of the absorbent resin particles is surface-treated with the water-insoluble inorganic particles (f), so that the blocking resistance and the liquid permeability of the absorbent resin particles are improved.

Examples of the water-insoluble inorganic particles (f) include colloidal silica, fumed silica, clay and talc, and colloidal silica and silica are preferable and further preferable from the viewpoint of availability, ease of handling and absorption performance. Is colloidal silica. One type of water-insoluble inorganic particles (f) may be used alone, or two or more types may be used in combination.

The amount (% by weight) of the water-insoluble inorganic particles (f) used is preferably 0.01 to 5, more preferably 0.05 to 1, and particularly preferably 0.05 to 1 part by weight based on 100 parts by weight of the absorbent resin from the viewpoint of absorption performance. Is 0.1 to 0.5.

When the water-insoluble inorganic particles (f) are contained, it is preferable to mix the absorbent resin particles and the water-insoluble inorganic particles (f), and the mixing is carried out in the same manner as the above-mentioned mixing of the polyvalent metal salt (e). It can be done, and the conditions are the same.

After performing the step of mixing the water-insoluble inorganic particles (f), the step of adjusting the particle size of the absorbent resin particles may be performed. The particle size adjustment can be performed in the same manner as the particle size adjustment described above, and the particle size after the particle size adjustment is also the same.

The absorbent resin particles of the present invention are, if necessary, preservatives, antifungal agents, antibacterial agents, and oxidations of additives (for example, known (described in JP-A-2003-225565 and JP-A-2006-131767)). Inhibitors, UV absorbers, colorants, fragrances, deodorants, liquid permeability improvers, organic fibrous substances, etc.) can also be used. When these additives are used, the content (% by weight) of the additives is preferably 0.001 to 10, more preferably 0.01 to 5, particularly preferably 0.01 to 10, based on the weight of the absorbent resin particles. It is 0.05 to 1, most preferably 0.1 to 0.5.

Further, the absorbent resin particles of the present invention preferably have a pH of 5.80 to 7.20 when the absorbent resin particles are contained in an amount of 0.5% by weight based on the weight of the physiological saline solution. More preferably, it is 80 to 6.50. If it is within this range, it becomes weakly acidic and less likely to cause fog, which is preferable.

The absorbent resin particles of the present invention are measured by the Demand Wettingity test method (hereinafter, also referred to as DW test), the time until the absorption amount reaches 2 g (t1) and the time until the absorption amount reaches 20 g (the time until the absorption amount reaches 20 g). The ratio of t2) (t2 / t1) is 2 to 20, preferably 3 to 15, and more preferably 4 to 10. If t2 / t1 is less than 2, the initial absorption rate is slow, the leakage property is deteriorated, the dryness of the diaper is lost, and rash and the like are likely to occur. Further, when t2 / t1 exceeds 20, spot absorption is likely to occur at the urine absorption site, and the leakage property is deteriorated.
Further, the gel bed transmittance (hereinafter, also referred to as GBP) at 0 psi swelling pressure is 40 darcies or more, preferably 45 darcies or more, and more preferably 50 darcies or more. When the GBP is less than 40 darcies, even if t2 / t1 is in the range of 2 to 20, urine diffusion is inhibited by the swelling gel in a thin disposable diaper having a high SAP ratio, and the leakage property is deteriorated.
The ratio (t2 / t1) of the time (t1) for the absorption amount to reach 2 g and the time (t2) for the absorption amount to reach 20 g measured in the DW test is 2 to 20, and the absorption pressure is 0 psi. Absorptive resin particles having a gelbed transmittance (hereinafter, also referred to as GBP) of 40 darcies or more are stable and have excellent absorption performance (liquid diffusivity, absorption rate) under any condition regardless of under load or under load. , And the amount of absorption), and the anti-fog resistance of the absorbent article becomes good.

The absorbable resin particles of the present invention preferably have a time (t1) of 5 to 60 seconds until the amount of absorption reaches 2 g in the Demand Wettingity test method. When this condition is satisfied, uneven gel swelling at the absorption site is suppressed, which is preferable.

The absorbent resin particles of the present invention preferably have a centrifugal retention amount of 25 to 36 g / g according to the CRC test method of physiological saline and an absorption rate of 40 seconds or less measured by the Voltex test method. When this condition is satisfied, the amount of free water in the disposable diaper absorber is reduced, which is preferable from the viewpoint of dryness.

Gelbed permeability (GBP) at 0 psi swelling pressure, absorption rate under no load measured by the Demand Wettingability test method, centrifugal retention capacity by the CRC test method, and absorption rate measured by the Vortex test method are 25 ±. It is measured by the following methods in a room at 2 ° C. and a humidity of 50 ± 10%. The temperature of the physiological saline to be used is adjusted to 25 ° C. ± 2 ° C. in advance before use.

<Absorption rate under no load measured in the Demand Wettingity test>
When measured by the DW method described in JP-A-2014-005472 using 0.50 g of absorbable resin particles and physiological saline, the amount of absorption (ml / g) from the start of water absorption is 2.0. The time required to obtain the above value is defined as the absorption rate under no load measured in the Demand Wetability test. The DW test determines the suction capacity of the absorbent resin under no load on a measuring table connected to the burette and the conduit.

<Gelbed permeability test at swelling pressure at 0 psi>
It is measured according to the GBP test method at 0 psi swelling pressure described in Japanese Patent No. 5236668 (unit: [darkies]). The higher the GBP, the better the absorption rate of the absorbent resin particles and the liquid permeability between the swelling gels.

<Centrimental retention of saline>
Measured according to the CRC test method (Centrifuge retention capacity test method) described in Japanese Patent No. 5236668, 0.200 g of absorbent resin particles were not added to physiological saline (0.9 mass% sodium chloride aqueous solution). Free swelling under pressure for 30 minutes, then drained with a centrifuge (290 G, 3 minutes), and the amount of physiological saline retained by the absorbent resin particles even after draining (physiology retained per 1 g of resin particles). Amount of saline solution: Unit; [g / g]) is measured. The higher the CRC, the higher the water absorption performance of the absorbent resin particles.

<Absorption rate measured in the Vortex test>
2.000 g of absorbable resin particles required to completely absorb 50 g of physiological saline stirred at 600 rpm in a 100 ml tall beaker with a flat bottom specified in JIS R 3503. The time (unit: seconds) is measured according to JIS K7224-1996 and is the absorption rate measured in the Vortex test.

The apparent density (g / ml) of the absorbent resin particles of the present invention is preferably 0.54 to 0.70, more preferably 0.56 to 0.65, and particularly preferably 0.58 to 0.60. .. Within this range, the anti-fog resistance of the absorbent article becomes even better. The apparent density can be measured in the same manner as in the case of the crosslinked polymer (A).

The shape of the absorbent resin particles is not particularly limited, and examples thereof include amorphous crushed particles, phosphorus flakes, pearl particles, and rice granules. 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 absorbent resin particles of the present invention may be used alone as an absorber, or may be used together with other materials as an absorber.
As another material, a fibrous material is preferable. The structure and manufacturing method of the absorber when used together with the fibrous material are the same as those known (Japanese Patent Laid-Open Nos. 2003-225565, 2006-131767, 2005-097569, etc.). is there.

The fibrous material is preferably a cellulosic fiber, an organic synthetic fiber, or a mixture of the cellulosic fiber and the organic synthetic fiber.

Examples of the cellulosic fiber include natural fibers such as fluff pulp and cellulosic chemical fibers such as viscose rayon, acetate and cupra. The raw material (conifer, hardwood, etc.), production method (chemical pulp, semi-chemical pulp, mechanical pulp, CTMP, etc.) and bleaching method of the cellulosic natural fiber are not particularly limited.

Examples of the organic synthetic fiber include polypropylene fiber, polyethylene fiber, polyamide fiber, polyacrylonitrile fiber, polyester fiber, polyvinyl alcohol fiber, polyurethane fiber and heat-sealing composite fiber (the fiber having a different melting point). Examples thereof include fibers in which at least two types of fibers are combined into a sheath core type, an eccentric type, a parallel type, etc., a fiber in which at least two types of the above fibers are blended, and a fiber in which the surface layer of the above fibers is modified).

Among these fibrous materials, cellulose-based natural fibers, polypropylene-based fibers, polyethylene-based fibers, polyester-based fibers, heat-sealing composite fibers and mixed fibers thereof are preferable, and more preferable are obtained. Fluff pulp, heat-sealing composite fiber, and a mixed fiber thereof are excellent in shape retention after water absorption of the water absorbing agent.

The length and thickness of the fibrous material are not particularly limited, and can be preferably used as long as the length is in the range of 1 to 200 mm and the thickness is in the range of 0.1 to 100 denier. The shape is not particularly limited as long as it is fibrous, and examples thereof include a thin cylindrical shape, a split yarn shape, a staple shape, a filament shape, and a web shape.

In the case of an absorber containing the absorbent resin particles and the fibrous material, the weight ratio of the absorbent resin particles and the fibrous material (weight of the absorbent resin particles / weight of the fibrous material) is 40/60. It is preferably ~ 90/10, and more preferably 70/30 to 80/20.

The absorber of the present invention contains the above-mentioned absorbent resin particles. The absorber of the present invention may be an absorber containing the absorbent resin particles alone, or may be an absorber containing the absorbent resin particles and the fibrous material. The absorber of the present invention can be used as an absorbent article. Absorbent articles include not only sanitary products such as disposable diapers and sanitary napkins, but also various uses such as absorption and retention agents for various aqueous liquids and gelling agents (for example, pet urine absorbents and urine gels for portable toilets). Agents, fruit and vegetable freshness preservatives, meat and seafood drip absorbers, ice packs, disposable cairo, battery gelling agents, plant and soil water retention agents, anti-condensation agents, water blocking materials, packing materials, artificial snow Etc.) can be applied as used. The method for producing the absorbent article and the like are the same as those known (described in JP-A-2003-225565, JP-A-2006-131767, JP-A-2005-097569, etc.).

Hereinafter, the present invention will be further described with reference to Examples and Comparative Examples, but the present invention is not limited thereto.

<Example 1>
135 parts of acrylic acid (manufactured by Mitsubishi Chemical Corporation, 100% purity, the same applies hereinafter), 0.51 parts of pentaerythritol triallyl ether (manufactured by Daiso Co., Ltd., the same applies hereinafter), and 479 parts of deionized water. The temperature was maintained at 3 ° C. while stirring and mixing. After influxing nitrogen into this mixture to reduce the amount of dissolved oxygen to 1 ppm or less, 0.5 part of 1% hydrogen peroxide aqueous solution and 1 part of 2% ascorbic acid aqueous solution and 2% 2,2'-azobis amidinopropane 0.3 part of the dihydrochloride aqueous solution was added and mixed to initiate polymerization. After the temperature of the mixture reached 80 ° C., a hydrogel (1) was obtained by polymerizing at 80 ± 2 ° C. for about 5 hours.

Next, while shredding the entire amount of the obtained hydrogel (1) with a mincing machine (ROYAL 12VR-400K), 180 parts of a 30% sodium hydroxide aqueous solution was added, and the hydrophobic substance (C1-1) was continued. 0.06 part of sucrose stearic acid ester was added and mixed and neutralized to obtain a shredded gel. Further, the shredded gel was dried with a ventilation type band dryer (140 ° C., wind speed 2 m / sec) to obtain a dried product. The dried product was pulverized with a juicer mixer (OSTERIZER BLENDER manufactured by Oster), sieved, and adjusted to a particle size range of 710 to 150 μm opening to obtain resin particles (B1).

10% water of ethylene glycol diglycidyl ether (Denacol EX-810 manufactured by Nagase Kasei Kogyo Co., Ltd.) while stirring 100 parts of the obtained resin particles (B1) at high speed (high-speed stirring turbulizer manufactured by Hosokawa Micron: rotation speed 2000 rpm). / While spraying 1.4 parts of a mixed solution of methanol (mixing ratio of water: methanol is 70:30) and 0.004 parts of hydrophobic substance (C2-1) carboxy-modified polysiloxane (manufactured by Shin-Etsu Chemical Industry Co., Ltd.) In addition, the mixture was mixed and allowed to stand in a circulating air dryer (manufactured by Tabai Espec Co., Ltd.) at 140 ° C. for 30 minutes for surface cross-linking to obtain the absorbent resin particles (1) of the present invention. Further, 0.028% of the hydrophobic substance (C) was present inside the absorbent resin particles (1), and 0.012% of the hydrophobic substance (C) was present on the surface of the absorbent resin particles (1). The apparent density was 0.59 g / ml.

<Example 2>
"Pentaerythritol triallyl ether 0.51 part" was changed to "Pentaerythritol triallyl ether 0.68 part", and "deionized water 479 parts" was changed to "deionized water 365 parts" and "hydrophobic substance (C1)". -1) 0.06 parts of sucrose stearic acid ester "," 0.135 parts of hydrophobic substance (C1-2) Mg stearate "," ethylene glycol diglycidyl ether (manufactured by Nagase Kasei Kogyo Co., Ltd., Denacol EX- 810) 10% water / methanol mixed solution (water: methanol mixing ratio is 70:30) 1.4 parts and hydrophobic substance (C2-1) carboxy-modified polysiloxane (manufactured by Shin-Etsu Chemical Industry Co., Ltd.) 0.004 1 part ”is a 10% water / methanol mixed solution of ethylene glycol diglycidyl ether (Denacol EX-810 manufactured by Nagase Kasei Kogyo Co., Ltd.) (water: methanol mixing ratio is 70:30) 1.6 parts and hydrophobic substance (C2) -1) Absorbent resin particles (2) of the present invention were obtained in the same manner as in Example 1 except that the mixture was changed to 0.013 parts of carboxy-modified polysiloxane (manufactured by Shin-Etsu Chemical Industry Co., Ltd.). Further, 0.059% of the hydrophobic substance (C) was present inside the absorbent resin particles (2), and 0.031% of the hydrophobic substance (C) was present on the surface of the absorbent resin particles (2). The apparent density was 0.68 g / ml.

<Example 3>
"Pentaerythritol triallyl ether 0.51 part" was changed to "Pentaerythritol triallyl ether 0.068 part", and "deionized water 479 parts" was changed to "deionized water 287 parts" and "hydrophobic substance (C1)". -1) 0.06 parts of sucrose stearic acid ester "," 0.338 parts of hydrophobic substance (C1-3) sorbit stearic acid ester "," ethylene glycol diglycidyl ether (manufactured by Nagase Kasei Kogyo Co., Ltd., Denacol EX) -810) 10% water / methanol mixed solution (water: methanol mixing ratio is 70:30) 1.4 parts and hydrophobic substance (C2-1) carboxy-modified polysiloxane (manufactured by Shin-Etsu Chemical Industry Co., Ltd.) 0. "004 parts" is 1.8 parts of "ethylene glycol diglycidyl ether (manufactured by Nagase Kasei Kogyo Co., Ltd., Denacol EX-810) in a 10% water / methanol mixed solution (water: methanol mixing ratio is 70:30) and a hydrophobic substance. Absorbent resin particles (3) of the present invention were obtained in the same manner as in Example 1 except that (C2-1) carboxy-modified polysiloxane (manufactured by Shin-Etsu Chemical Industry Co., Ltd.) was changed to 0.035 parts. Further, 0.15% of the hydrophobic substance (C) was present inside the absorbent resin particles (3), and 0.077% of the hydrophobic substance (C) was present on the surface of the absorbent resin particles (3). The apparent density was 0.65 g / ml.

<Example 4>
"0.06 parts of hydrophobic substance (C1-1) sucrose stearic acid ester", "0.135 parts of hydrophobic substance (C1-2) Mg stearate", "ethylene glycol diglycidyl ether (Nagase Kasei Kogyo)" Denacol EX-810) 10% water / methanol mixed solution (water: methanol mixing ratio is 70:30) 1.4 parts and hydrophobic substance (C2-1) carboxy-modified polysiloxane (Shin-Etsu Chemical Industry Co., Ltd.) "0.004 parts (manufactured by the company)" is 1.9% of "ethylene glycol diglycidyl ether (manufactured by Nagase Kasei Kogyo Co., Ltd., Denacol EX-810) in a 10% water / methanol mixed solution (water: methanol mixing ratio is 70:30)". The absorbent resin particles (4) of the present invention are the same as in Example 1 except that the part and the hydrophobic substance (C2-2) amino-modified polysiloxane (manufactured by Shin-Etsu Chemical Industry Co., Ltd.) are changed to 0.035 part. ) Was obtained. Further, 0.062% of the hydrophobic substance (C) was present inside the absorbent resin particles (4), and 0.041% of the hydrophobic substance (C) was present on the surface of the absorbent resin particles (4). The apparent density was 0.68 g / ml. The apparent density was 0.55 g / ml.

<Example 5>
"Pentaerythritol triallyl ether 0.51 part" was changed to "Pentaerythritol triallyl ether 0.68 part", and "deionized water 479 parts" was changed to "deionized water 365 parts" and "hydrophobic substance (C1)". -1) 0.06 parts of sucrose stearic acid ester "," 0.338 parts of hydrophobic substance (C1-3) sorbit stearic acid ester "," ethylene glycol diglycidyl ether (manufactured by Nagase Kasei Kogyo Co., Ltd., Denacol EX) -810) 10% water / methanol mixed solution (water: methanol mixing ratio is 70:30) 1.4 parts and hydrophobic substance (C2-1) carboxy-modified polysiloxane (manufactured by Shin-Etsu Chemical Industry Co., Ltd.) 0. "004 parts" is 1.3 parts of "ethylene glycol diglycidyl ether (manufactured by Nagase Kasei Kogyo Co., Ltd., Denacol EX-810) in a 10% water / methanol mixed solution (water: methanol mixing ratio is 70:30) and a hydrophobic substance. (C2-2) Amino-modified polysiloxane (manufactured by Shin-Etsu Chemical Industry Co., Ltd.) 0.004 parts "was obtained in the same manner as in Example 1 except that the absorbent resin particles (5) of the present invention were obtained. Further, 0.16% of the hydrophobic substance (C) was present inside the absorbent resin particles (5), and 0.048% of the hydrophobic substance (C) was present on the surface of the absorbent resin particles (5). The apparent density was 0.54 g / ml.

<Example 6>
"Pentaerythritol triallyl ether 0.51 part" was changed to "Pentaerythritol triallyl ether 0.44 part", and "deionized water 479 parts" was changed to "deionized water 287 part" and "ethylene glycol diglycidyl ether". (Nagase Kasei Kogyo Co., Ltd., Denacol EX-810) 10% water / methanol mixed solution (water: methanol mixing ratio is 70:30) 1.4 parts and hydrophobic substance (C2-1) carboxy-modified polysiloxane ( "0.004 parts (manufactured by Shin-Etsu Chemical Industry Co., Ltd.)" in a 10% water / methanol mixed solution of "ethylene glycol diglycidyl ether (manufactured by Nagase Kasei Kogyo Co., Ltd., Denacol EX-810) (mixing ratio of water: methanol is 70:30)" ) 1.5 parts and hydrophobic substance (C2-2) amino-modified polysiloxane (manufactured by Shin-Etsu Chemical Industry Co., Ltd.) 0.013 parts " Resin particles (6) were obtained. Further, 0.028% of the hydrophobic substance (C) was present inside the absorbent resin particles (6), and 0.017% of the hydrophobic substance (C) was present on the surface of the absorbent resin particles (6). The apparent density was 0.68 g / ml.

<Example 7>
"0.51 part of pentaerythritol triallyl ether" was changed to "0.68 part of pentaerythritol triallyl ether", and "0.06 part of hydrophobic substance (C1-1) sucrose stearate ester" was changed to "0.06 part". Hydrophobic substance (C1-1) sucrose stearic acid ester 0.338 parts ", 10% water / methanol mixed solution of ethylene glycol diglycidyl ether (Nagase Kasei Kogyo Co., Ltd., Denacol EX-810) (water: methanol) Mixing ratio of 70:30) 1.4 parts and hydrophobic substance (C2-1) carboxy-modified polysiloxane (manufactured by Shin-Etsu Chemical Industry Co., Ltd.) 0.004 parts "is" ethylene glycol diglycidyl ether (Nagase Kasei Kogyo Co., Ltd.) , Denacol EX-810) 10% water / methanol mixed solution (water: methanol mixing ratio is 70:30) 1.7 parts and hydrophobic substance (C2-3) epoxy-modified polysiloxane (Shinetsu Chemical Industry Co., Ltd.) The absorbent resin particles (7) of the present invention were obtained in the same manner as in Example 1 except that the mixture was changed to "0.035 parts". Further, 0.16% of the hydrophobic substance (C) was present inside the absorbent resin particles (7), and 0.062% of the hydrophobic substance (C) was present on the surface of the absorbent resin particles (7). The apparent density was 0.70 g / ml.

<Example 8>
"0.51 part of pentaerythritol triallyl ether" was changed to "0.81 part of pentaerythritol triallyl ether", and "0.06 part of hydrophobic substance (C1-1) sucrose stearate" was changed to "0.06 part". Hydrophobic substance (C1-2) Mg stearate 0.06 parts "," deionized water 479 parts "" deionized water 365 parts "," ethylene glycol diglycidyl ether (manufactured by Nagase Kasei Kogyo Co., Ltd., Denacol EX- 810) 10% water / methanol mixed solution (water: methanol mixing ratio is 70:30) 1.4 parts and hydrophobic substance (C2-1) carboxy-modified polysiloxane (manufactured by Shin-Etsu Chemical Industry Co., Ltd.) 0.004 "Parts" is 1.7 parts of 10% water / methanol mixed solution of ethylene glycol diglycidyl ether (Denacol EX-810 manufactured by Nagase Kasei Kogyo Co., Ltd.) (mixing ratio of water: methanol is 70:30) and hydrophobic substances (parts). C2-3) Absorbent resin particles (8) of the present invention were obtained in the same manner as in Example 1 except that the epoxy-modified polysiloxane (manufactured by Shin-Etsu Chemical Industry Co., Ltd.) was changed to 0.004 part. Further, 0.027% of the hydrophobic substance (C) was present inside the absorbent resin particles (8), and 0.012% of the hydrophobic substance (C) was present on the surface of the absorbent resin particles (8). The apparent density was 0.69 g / ml.

<Example 9>
"0.06 parts of hydrophobic substance (C1-1) sucrose stearate", "0.20 parts of hydrophobic substance (C1-3) sorbit stearate", "479 parts of deionized water" 287 parts of deionized water ", 1.4 parts of 10% water / methanol mixed solution of ethylene glycol diglycidyl ether (Denacol EX-810 manufactured by Nagase Kasei Kogyo Co., Ltd.) (mixing ratio of water: methanol is 70:30) and Hydrophobic substance (C2-1) carboxy-modified polysiloxane (manufactured by Shin-Etsu Chemical Industry Co., Ltd.) 0.004 parts "is 10% water / methanol of ethylene glycol diglycidyl ether (manufactured by Nagase Kasei Kogyo Co., Ltd., Denacol EX-810). Except for changing to 1.8 parts of mixed solution (mixing ratio of water: methanol is 70:30) and 0.013 parts of hydrophobic substance (C2-3) epoxy-modified polysiloxane (manufactured by Shin-Etsu Chemical Industry Co., Ltd.). The absorbent resin particles (9) of the present invention were obtained in the same manner as in Example 1. Further, 0.09% of the hydrophobic substance (C) was present inside the absorbent resin particles (9), and 0.041% of the hydrophobic substance (C) was present on the surface of the absorbent resin particles (9). The apparent density was 0.58 g / ml.

<Example 10>
"0.51 part of pentaerythritol triallyl ether" was changed to "0.88 part of pentaerythritol triallyl ether", and "0.06 part of hydrophobic substance (C1-1) sucrose stearate ester" was changed to "0.06 part". 0.135 parts of hydrophobic substance (C1-3) sorbit stearate ester "," 10% water / methanol mixed solution of ethylene glycol diglycidyl ether (Nagase Kasei Kogyo Co., Ltd., Denacol EX-810) (water: methanol) Mixing ratio is 70:30) 1.4 parts and hydrophobic substance (C2-1) carboxy-modified polysiloxane (manufactured by Shin-Etsu Chemical Industry Co., Ltd.) 0.004 parts "is" ethylene glycol diglycidyl ether (manufactured by Nagase Kasei Kogyo Co., Ltd.) , Denacol EX-810) 10% water / methanol mixed solution (water: methanol mixing ratio is 70:30) 1.5 parts and hydrophobic substance (C2-1) carboxy-modified polysiloxane (manufactured by Shin-Etsu Chemical Industry Co., Ltd.) ) 0.004 parts and 0.0004 parts of hydrophobic substance (C2-4) polyether-modified polysiloxane ”, the absorbent resin particles (10) of the present invention were obtained in the same manner as in Example 1. It was. Further, 0.057% of the hydrophobic substance (C) was present inside the absorbent resin particles (10), and 0.027% of the hydrophobic substance (C) was present on the surface of the absorbent resin particles (10). The apparent density was 0.57 g / ml.

<Example 11>
"0.06 parts of hydrophobic substance (C1-1) sucrose stearate", "0.338 parts of hydrophobic substance (C1-1) sucrose stearate", "479 parts of deionized water""365 parts of deionized water", "10% water / methanol mixed solution of ethylene glycol diglycidyl ether (Denacol EX-810 manufactured by Nagase Kasei Kogyo Co., Ltd.) (water: methanol mixing ratio is 70:30) 1.4 parts And hydrophobic substance (C2-1) carboxy-modified polysiloxane (manufactured by Shin-Etsu Chemical Industry Co., Ltd.) 0.004 parts "in 10% water of ethylene glycol diglycidyl ether (manufactured by Nagase Kasei Kogyo Co., Ltd., Denacol EX-810) / 1.8 parts of methanol mixed solution (water: methanol mixing ratio is 70:30) and 0.013 parts of hydrophobic substance (C2-1) carboxy-modified polysiloxane (manufactured by Shin-Etsu Chemical Industry Co., Ltd.) and hydrophobic substance (C2) -4) Absorbent resin particles (11) of the present invention were obtained in the same manner as in Example 1 except that the mixture was changed to 0.0013 parts of polyether-modified polysiloxane. Further, 0.15% of the hydrophobic substance (C) was present inside the absorbent resin particles (11), and 0.063% of the hydrophobic substance (C) was present on the surface of the absorbent resin particles (11). The apparent density was 0.60 g / ml.

<Example 12>
"0.51 part of pentaerythritol triallyl ether" was changed to "0.68 part of pentaerythritol triallyl ether", and "0.06 part of hydrophobic substance (C1-1) sucrose stearate" was changed to "0.06 part". Hydrophobic substance (C1-2) Mg stearate 0.06 parts ”,“ Deionized water 479 parts ”,“ Deionized water 287 parts ”,“ Hydrophobic substance (C2-1) carboxy-modified polysiloxane (Shin-Etsu Chemical) "0.004 parts manufactured by Kogyo Co., Ltd.""0.035 parts of hydrophobic substance (C2-1) carboxy-modified polysiloxane (manufactured by Shin-Etsu Chemical Industry Co., Ltd.) and hydrophobic substance (C2-4) polyether-modified polysiloxane The absorbent resin particles (12) of the present invention were obtained in the same manner as in Example 1 except that the amount was changed to 0.0035 parts. Further, 0.026% of the hydrophobic substance (C) was present inside the absorbent resin particles (12), and 0.032% of the hydrophobic substance (C) was present on the surface of the absorbent resin particles (12). The apparent density was 0.56 g / ml.

<Example 13>
"0.51 part of pentaerythritol triallyl ether" was changed to "0.68 part of pentaerythritol triallyl ether", and "0.06 part of hydrophobic substance (C1-1) sucrose stearate ester" was changed to "0.06 part". Hydrophobic substance (C1-3) sorbit stearate ester 0.06 parts "," 10% water / methanol mixed solution of ethylene glycol diglycidyl ether (Nagase Kasei Kogyo Co., Ltd., Denacol EX-810) (water: methanol) Mixing ratio is 70:30) 1.4 parts and hydrophobic substance (C2-1) carboxy-modified polysiloxane (manufactured by Shin-Etsu Chemical Industry Co., Ltd.) 0.004 parts "is" ethylene glycol diglycidyl ether (manufactured by Nagase Kasei Kogyo Co., Ltd.) , Denacol EX-810) 10% water / methanol mixed solution (water: methanol mixing ratio is 70:30) 2.0 parts and hydrophobic substance (C2-2) amino-modified polysiloxane (manufactured by Shin-Etsu Chemical Industry Co., Ltd.) ) 0.013 parts and 0.0013 parts of hydrophobic substance (C2-4) polyether-modified polysiloxane ”, the absorbent resin particles (13) of the present invention were obtained in the same manner as in Example 1. It was. Further, 0.027% of the hydrophobic substance (C) was present inside the absorbent resin particles (13), and 0.018% of the hydrophobic substance (C) was present on the surface of the absorbent resin particles (13). The apparent density was 0.69 g / ml.

<Example 14>
"0.51 part of pentaerythritol triallyl ether" was changed to "0.88 part of pentaerythritol triallyl ether", and "0.06 part of hydrophobic substance (C1-1) sucrose stearate ester" was changed to "0.06 part". Hydrophobic substance (C1-1) sucrose stearic acid ester 0.135 parts "," deionized water 479 parts "" deionized water 365 parts "," ethylene glycol diglycidyl ether (manufactured by Nagase Kasei Kogyo Co., Ltd., Denacol EX-810) 10% water / methanol mixed solution (water: methanol mixing ratio is 70:30) 1.4 parts and hydrophobic substance (C2-1) carboxy-modified polysiloxane (manufactured by Shin-Etsu Chemical Industry Co., Ltd.) 0 ".004 parts" is "100% water / methanol mixed solution of ethylene glycol diglycidyl ether (Denacol EX-810 manufactured by Nagase Kasei Kogyo Co., Ltd.) (water: methanol mixing ratio is 70:30) 1.4 parts and hydrophobicity. Example 1 except that the substance (C2-2) amino-modified polysiloxane (manufactured by Shin-Etsu Chemical Industry Co., Ltd.) was changed to 0.035 parts and the hydrophobic substance (C2-4) polyether-modified polysiloxane 0.0035 parts. In the same manner as above, the absorbent resin particles (13) of the present invention were obtained. Further, 0.061% of the hydrophobic substance (C) was present inside the absorbent resin particles (14), and 0.042% of the hydrophobic substance (C) was present on the surface of the absorbent resin particles (14). The apparent density was 0.57 g / ml.

<Example 15>
"Hydrophobic substance (C1-1) sucrose stearate ester 0.06 parts""hydrophobic substance (C1-2) Mg stearate 0.338 parts", "deionized water 479 parts""de-ionized" 287 parts of ionized water ", 1.4 parts of 10% water / methanol mixed solution of ethylene glycol diglycidyl ether (Denacol EX-810 manufactured by Nagase Kasei Kogyo Co., Ltd.) (mixing ratio of water: methanol is 70:30) and hydrophobic 10% water / methanol mixture of ethylene glycol diglycidyl ether (Denacol EX-810, manufactured by Nagase Kasei Kogyo Co., Ltd.) with 0.004 parts of sex substance (C2-1) carboxy-modified polysiloxane (manufactured by Shin-Etsu Chemical Industry Co., Ltd.) 1.6 parts of solution (mixing ratio of water: methanol is 70:30) and 0.004 parts of hydrophobic substance (C2-2) amino-modified polysiloxane (manufactured by Shin-Etsu Chemical Industry Co., Ltd.) and hydrophobic substance (C2-4) The absorbent resin particles (15) of the present invention were obtained in the same manner as in Example 1 except that the mixture was changed to 0.0004 parts of polyether-modified polysiloxane. Further, 0.15% of the hydrophobic substance (C) was present inside the absorbent resin particles (15), and 0.054% of the hydrophobic substance (C) was present on the surface of the absorbent resin particles (15). The apparent density was 0.65 g / ml.

<Example 16>
"0.51 part of pentaerythritol triallyl ether" was changed to "0.88 part of pentaerythritol triallyl ether", and "0.06 part of hydrophobic substance (C1-1) sucrose stearate" was changed to "0.06 part". Hydrophobic substance (C1-2) Mg stearate 0.338 parts "," Ethylene glycol diglycidyl ether (manufactured by Nagase Kasei Kogyo Co., Ltd., Denacol EX-810) 10% water / methanol mixed solution (water: methanol mixture) The ratio is 70:30) 1.4 parts and hydrophobic substance (C2-1) carboxy-modified polysiloxane (manufactured by Shin-Etsu Chemical Industry Co., Ltd.) 0.004 parts "is" ethylene glycol diglycidyl ether (manufactured by Nagase Kasei Kogyo Co., Ltd.). Denacol EX-810) 10% water / methanol mixed solution (water: methanol mixing ratio is 70:30) 1.4 parts and hydrophobic substance (C2-3) epoxy-modified polysiloxane (manufactured by Shin-Etsu Chemical Industry Co., Ltd.) Absorbent resin particles (16) of the present invention were obtained in the same manner as in Example 1 except that 0.013 parts and 0.0013 parts of hydrophobic substance (C2-4) polyether-modified polysiloxane were changed. .. Further, 0.15% of the hydrophobic substance (C) was present inside the absorbent resin particles (16), and 0.065% of the hydrophobic substance (C) was present on the surface of the absorbent resin particles (16). The apparent density was 0.62 g / ml.

<Example 17>
"0.06 parts of hydrophobic substance (C1-1) sucrose stearate", "0.06 parts of hydrophobic substance (C1-3) sorbit stearate", "479 parts of deionized water" 365 parts of deionized water ", 1.4 parts of 10% water / methanol mixed solution of ethylene glycol diglycidyl ether (Denacol EX-810 manufactured by Nagase Kasei Kogyo Co., Ltd.) (mixing ratio of water: methanol is 70:30) and Hydrophobic substance (C2-1) carboxy-modified polysiloxane (manufactured by Shin-Etsu Chemical Industry Co., Ltd.) 0.004 parts "is 10% water / methanol of ethylene glycol diglycidyl ether (manufactured by Nagase Kasei Kogyo Co., Ltd., Denacol EX-810). Mixed solution (water: methanol mixing ratio is 70:30) 1.6 parts and hydrophobic substance (C2-3) Ester-modified polysiloxane (manufactured by Shin-Etsu Chemical Industry Co., Ltd.) 0.035 parts and hydrophobic substance (C2- 4) The absorbent resin particles (17) of the present invention were obtained in the same manner as in Example 1 except that the mixture was changed to 0.0035 parts of polyether-modified polysiloxane. Further, 0.026% of the hydrophobic substance (C) was present inside the absorbent resin particles (17), and 0.032% of the hydrophobic substance (C) was present on the surface of the absorbent resin particles (17). The apparent density was 0.59 g / ml.

<Example 18>
"0.06 parts of hydrophobic substance (C1-1) sucrose stearate ester", "0.135 parts of hydrophobic substance (C1-2) Mg stearate", "deionized water 479 parts" 287 parts of ionized water ", 1.4 parts of 10% water / methanol mixed solution of ethylene glycol diglycidyl ether (Denacol EX-810 manufactured by Nagase Kasei Kogyo Co., Ltd.) (mixing ratio of water: methanol is 70:30) and hydrophobic 10% water / methanol mixture of ethylene glycol diglycidyl ether (Denacol EX-810, manufactured by Nagase Kasei Kogyo Co., Ltd.) with 0.004 parts of sex substance (C2-1) carboxy-modified polysiloxane (manufactured by Shin-Etsu Chemical Industry Co., Ltd.) 1.8 parts of solution (mixing ratio of water: methanol is 70:30) and hydrophobic substance (C2-3) 0.004 part of epoxy-modified polysiloxane (manufactured by Shin-Etsu Chemical Industry Co., Ltd.) and hydrophobic substance (C2-4) The absorbent resin particles (18) of the present invention were obtained in the same manner as in Example 1 except that the mixture was changed to 0.0004 parts of polyether-modified polysiloxane. Further, 0.061% of the hydrophobic substance (C) was present inside the absorbent resin particles (18), and 0.024% of the hydrophobic substance (C) was present on the surface of the absorbent resin particles (18). The apparent density was 0.59 g / ml.

<Comparative example 1>
"0.06 parts of hydrophobic substance (C1-1) sucrose stearate" was changed to "0 parts of hydrophobic substance (C1-1) sucrose stearate", and "479 parts of deionized water""287 parts of deionized water", "10% water / methanol mixed solution of ethylene glycol diglycidyl ether (Nagase Kasei Kogyo Co., Ltd., Denacol EX-810) (water: methanol mixing ratio is 70:30) 1.4 10% water of "ethylene glycol diglycidyl ether (Denacol EX-810, manufactured by Nagase Kasei Kogyo Co., Ltd.)" in 0.004 parts and hydrophobic substance (C2-1) carboxy-modified polysiloxane (manufactured by Shin-Etsu Chemical Industry Co., Ltd.) / Methanol mixed solution (water: methanol mixing ratio is 70:30) 1.8 parts and hydrophobic substance (C2-1) carboxy-modified polysiloxane (manufactured by Shin-Etsu Chemical Industry Co., Ltd.) 0 parts ” In the same manner as in Example 1, absorbent resin particles (19) of Comparative Example were obtained. Further, 0% of the hydrophobic substance (C) was present both inside and on the surface of the absorbent resin particles (19). The apparent density was 0.54 g / ml.

<Comparative example 2>
Change "479 parts of deionized water" to "365 parts of deionized water" and change "0.06 parts of hydrophobic substance (C1-1) sucrose stearate" to "hydrophobic substance (C1-1)". 0.135 parts of sucrose stearic acid ester, 0.51 part of pentaerythritol triallyl ether, 0.68 parts of pentaerythritol triallyl ether, ethylene glycol diglycidyl ether (manufactured by Nagase Kasei Kogyo Co., Ltd., Denacol EX-810) 10% water / methanol mixed solution (water: methanol mixing ratio is 70:30) 1.4 parts and hydrophobic substance (C2-1) carboxy-modified polysiloxane (manufactured by Shin-Etsu Chemical Industry Co., Ltd.) "0.004 parts" is 1.6 parts of "ethylene glycol diglycidyl ether (manufactured by Nagase Kasei Kogyo Co., Ltd., Denacol EX-810) in a 10% water / methanol mixed solution (water: methanol mixing ratio is 70:30) and hydrophobic. Absorbent resin particles (20) of Comparative Example were obtained in the same manner as in Example 1 except that the sex substance (C2-1) carboxy-modified polysiloxane (manufactured by Shin-Etsu Chemical Industry Co., Ltd.) was 0 parts. Further, 0.057% of the hydrophobic substance (C) was present inside the absorbent resin particles (20), and 0.025% of the hydrophobic substance (C) was present on the surface of the absorbent resin particles (20). The apparent density was 0.60 g / ml.

<Comparative example 3>
"Hydrophobic substance (C1-1) sucrose stearic acid ester 0.06 part" was changed to "hydrophobic substance (C1-1) sucrose stearic acid ester 0 part", and "pentaerythritol triallyl ether 0" From ".51 parts" to "0.88 parts of pentaerythritol triallyl ether", 10% water / methanol mixed solution of ethylene glycol diglycidyl ether (manufactured by Nagase Kasei Kogyo Co., Ltd., Denacol EX-810) (water: methanol mixture) The ratio is 70:30) 1.4 parts and hydrophobic substance (C2-1) carboxy-modified polysiloxane (manufactured by Shinetsu Chemical Industry Co., Ltd.) 0.004 parts "is" ethylene glycol diglycidyl ether (manufactured by Nagase Kasei Kogyo Co., Ltd.). 1.7 parts of 10% water / methanol mixed solution of Denacol EX-810 (mixing ratio of water: methanol is 70:30) and hydrophobic substance (C2-1) carboxy-modified polysiloxane (manufactured by Shin-Etsu Chemical Industry Co., Ltd.) Absorbent resin particles (21) of Comparative Example were obtained in the same manner as in Example 1 except that "0.013 parts" was used. Further, 0% of the hydrophobic substance (C) was present inside the absorbent resin particles (21), and 0.008% of the hydrophobic substance (C) was present only on the surface of the absorbent resin particles (21). The apparent density was 0.60 g / ml.

<Comparative example 4>
"Hydrophobic substance (C1-1) sucrose stearate ester 0.06 parts" was changed to "hydrophobic substance (C1-2) Mg stearate 0.675 parts", and "pentaerythritol triallyl ether 0" From ".51 parts" to "0.68 parts of pentaerythritol triallyl ether", 10% water / methanol mixed solution of ethylene glycol diglycidyl ether (Denacol EX-810 manufactured by Nagase Kasei Kogyo Co., Ltd.) (water: methanol mixture) The ratio is 70:30) 1.4 parts and hydrophobic substance (C2-1) carboxy-modified polysiloxane (manufactured by Shin-Etsu Chemical Industry Co., Ltd.) 0.004 parts "is" ethylene glycol diglycidyl ether (manufactured by Nagase Kasei Kogyo Co., Ltd.). Absorbent resin particles of Comparative Example in the same manner as in Example 1 except that "1.5 parts of a 10% water / methanol mixed solution (water: methanol mixing ratio of 70:30)" of Denacol EX-810) was used. (22) was obtained. Further, 0.30% of the hydrophobic substance (C) was present inside the absorbent resin particles (22), and 0.11% of the hydrophobic substance (C) was present on the surface of the absorbent resin particles (22). The apparent density was 0.65 g / ml.

<Comparative example 5>
"Hydrophobic substance (C1-1) sucrose stearic acid ester 0.06 part" was changed to "hydrophobic substance (C1-1) sucrose stearic acid ester 0 part", and "pentaerythritol triallyl ether 0" From ".51 parts" to "0.88 parts of pentaerythritol triallyl ether", 10% water / methanol mixed solution of ethylene glycol diglycidyl ether (manufactured by Nagase Kasei Kogyo Co., Ltd., Denacol EX-810) (water: methanol mixture) The ratio is 70:30) 1.4 parts and hydrophobic substance (C2-1) carboxy-modified polysiloxane (manufactured by Shin-Etsu Chemical Industry Co., Ltd.) 0.004 parts "is" ethylene glycol diglycidyl ether (manufactured by Nagase Kasei Kogyo Co., Ltd.). 1.8 parts of 10% water / methanol mixed solution of Denacol EX-810 (mixing ratio of water: methanol is 70:30) and hydrophobic substance (C2-2) amino-modified polysiloxane (manufactured by Shin-Etsu Chemical Industry Co., Ltd.) Absorbent resin particles (23) of Comparative Example were obtained in the same manner as in Example 1 except that "0.05 part" was used. Further, 0% of the hydrophobic substance (C) was present inside the absorbent resin particles (23), and 0.03% of the hydrophobic substance (C) was present only on the surface of the absorbent resin particles (23). The apparent density was 0.57 g / ml.

For each of the absorbent resin particles obtained in Examples 1 to 18 and Comparative Examples 1 to 5, the absorption rate under no load measured by the DW test method [absorption rate (T1, T2, T2 / T1)], Gel bed permeability at 0 psi swelling pressure [GBP (0 psi swelling pressure)], centrifugal retention capacity of physiological saline (CRC), absorption rate measured by the Vortex test method [absorption rate (Vortex)] are measured by the following methods. And it is shown in Table 1.

<Absorption rate under no load measured by DW test>
Using 0.50 g of each of the absorbent resin particles obtained in Examples 1 to 18 and Comparative Examples 1 to 5 and physiological saline, the measurement was carried out by the above method. The DW test determines the suction capacity of the absorbent resin under no load on a measuring table connected to the burette and the conduit.

<Gelbed permeability test at swelling pressure at 0 psi>
The absorbent resin particles obtained in Examples 1 to 18 and Comparative Examples 1 to 5 were used for measurement by the above method. The higher this value, the better the absorption rate of the absorber and the liquid permeability between the swollen gels.

<Centrimental retention capacity of saline>
Using 0.200 g of the absorbent resin particles obtained in Examples 1 to 18 and Comparative Examples 1 to 5, the measurement was carried out by the above method. The higher this value, the higher the water absorption performance of the absorbent resin.

<Absorption rate measured in the Vortex test>
The absorbent resin particles obtained in Examples 1 to 18 and Comparative Examples 1 to 5 were used for measurement by the method described above.

From Table 1, the absorbent resin particles in the present invention effectively utilized the entire diaper without causing urine bias in the absorbent material used in the absorbent article (paper diaper, etc.) when applied to the absorbent article (paper diaper, etc.). It has the absorption rate pattern (T2 / T1) required to realize absorption, and has a hydrophobic substance with a polysiloxane structure on the surface, so it expresses high GBP and absorbs with a high SAP ratio like a thin diaper. It can be expected to have excellent urine diffusivity in the body. On the other hand, the absorbent resin of the comparative example does not have both the absorption rate pattern required for the absorption of urine in the absorber and the GBP. For example, Comparative Example 1 does not contain a hydrophobic substance both inside and on the surface, and does not have an appropriate absorption rate pattern. It is easy to see that the initial absorption rate is so fast that spot absorption occurs at the absorption site, resulting in urine leakage. Further, according to Comparative Examples 2 and 4, since the inside and the surface contain an appropriate hydrophobic substance, it has an appropriate absorption rate pattern, but since the GBP is low, the diffusion of urine is inhibited in the absorber of the thin diaper. It is thought that urine leaks. Comparative Examples 3 and 5 do not have a hydrophobic substance inside, but contain a hydrophobic substance having a polysiloxane structure on the surface, so that the initial absorption rate is slow and the late absorption rate is also slow. This promotes early urine diffusion in the absorber, but it is thought that since the late absorption rate is slow, it is difficult to efficiently absorb urine thereafter and urine leaks. From the above, two or more types of hydrophobic substances, the hydrophobic substance C1 required to realize the optimum absorption rate pattern and the hydrophobic substance C2 required to realize high GBP, are appropriately distributed on the surface and inside of the SAP. It turns out that what is good for diaper performance.

Subsequently, when the absorption rate pattern was appropriate, it was evaluated what kind of absorption characteristics it exhibited when applied to an absorbent article. Using the absorbent resin particles obtained in Examples 1 to 18 and Comparative Examples 1 to 5, an absorbent article (paper diaper) was prepared as follows, and the surface dryness value by the SDME method was evaluated. Is shown in Table 2.

<Preparation of absorbent articles (diapers) 1>
80 parts of fluff pulp and 120 parts of evaluation sample {absorbent resin particles} are mixed with an air flow type mixer {Padformer manufactured by Otec Co., Ltd.} to obtain a mixture, and then this mixture has a basis weight of about 500 g / The mixture was uniformly laminated on an acrylic plate (thickness 4 mm) so as to have ^{m 2, and pressed at a pressure of 5 kg / cm 2} for 30 seconds to obtain an absorber (1). This absorber (1) is cut into a rectangle of 10 cm x 40 cm, and water-absorbing paper (basis weight 15.5 g / m ² , manufactured by Advantech, filter paper No. 2) of the same size as the absorber is placed above and below each. Further, a paper diaper (1) was prepared by arranging a polyethylene sheet (polyethylene film UB-1 manufactured by Tamapoli Co., Ltd.) on the back surface and a non-woven fabric (basis weight 20 g / m ² , Ertus guard manufactured by Asahi Kasei Co., Ltd.) on the front surface. The weight ratio of the absorbent resin particles to the fibers (weight of the absorbent resin particles / weight of the fibers) was 60/40.

<Preparation of absorbent articles (diapers) 2>
Preparation of absorbent article (paper diaper) except that "80 parts of fluff pulp and 120 parts of evaluation sample {absorbent resin particles}" was changed to "60 parts of fluff pulp and 140 parts of evaluation sample {absorbent resin particles}" 1 The paper diaper (2) was adjusted in the same manner as in the above. The weight ratio of the absorbent resin particles to the fibers (weight of the absorbent resin particles / weight of the fibers) was 70/30.

<Surface dryness value by SDME method>
Paper diaper with sufficiently moistened detector of SDME (Surface Dryness Measurement Equipment) tester (manufactured by WK system) {artificial urine (potassium chloride 0.03% by weight, magnesium sulfate 0.08% by weight, sodium chloride 0.8% by weight) % And 99.09% by weight of deionized water) soaked the paper urine and left it for 60 minutes to prepare. } To set a 0% dryness value, then the detector of the SDME tester was prepared by drying a dry disposable diaper {a disposable diaper at 80 ° C. for 2 hours. } Was placed on top of it to set 100% dryness, and the SDME tester was calibrated. Next, set a metal ring (inner diameter 70 mm, length 50 mm) in the center of the disposable diaper to be measured, inject 80 ml of artificial urine, and when the artificial urine has been absorbed {until the gloss due to the artificial urine cannot be confirmed}, immediately Remove the metal ring, place three SDME detectors on the center of the disposable diaper and on the left and right {three locations at equal intervals of 10 cm from the edge of the disposable diaper}, start measuring the surface dryness value, and 5 minutes after the start of measurement. The values of were set to SD1-1 {center}, SD1-2 {left}, and SD1-3 {right}, respectively.
The artificial urine, the measurement atmosphere, and the neglected atmosphere were performed at 25 ± 5 ° C. and 65 ± 10% RH.

From Table 2, the absorbent resin particles of Examples exhibited excellent dryness even in disposable diapers having a high proportion of absorbent resin particles. In Comparative Example 1, since a hydrophobic substance is not contained inside, the absorption rate pattern is not appropriate and the dryness is inferior to that of the Example. Further, in Comparative Examples 2 and 4, the disposable diaper 1 in which the ratio of the absorbent resin particles is low maintains an appropriate dryness due to the presence of the hydrophobic substance inside the absorbent resin particles, but the disposable diaper in which the ratio of the absorbent resin particles is high is maintained. In No. 2, the dryness is lowered. It is considered that this is because the GBP is lower than that of the examples. Since Comparative Examples 3 and 5 do not have an appropriate absorption rate pattern, the dryness is low even in the disposable diaper 1 having a low ratio of the absorbent resin particles. From the above, it can be seen that having a slow absorption rate pattern in the early stage, normal in the middle stage, and a fast absorption rate pattern in the late stage and having a high GBP is effective for the dry performance of the disposable diaper.

The absorbent resin composition of the present invention has the features that both liquid permeability between swollen gels and absorption performance under load can be achieved, and blocking and discoloration during storage are unlikely to occur. Since the above effects are obtained, the absorbent resin composition of the present invention can be used for an absorbent article having a large amount of absorption and excellent reversibility and surface dryness by being applied to various absorbers, and is hygienic. Suitable for supplies.

Claims (11)

Includes a crosslinked polymer (A) of a monomer composition containing a water-soluble vinyl monomer (a1) and / or a vinyl monomer (a2) that becomes a water-soluble vinyl monomer (a1) by hydrolysis and an internal cross-linking agent (b). For absorbent resin particles, in the Demand Wetability test method, the time until the amount of absorption per 1 g of the absorbent resin particles in physiological saline reaches 2 g (t1) and the time until the amount of absorption reaches 20 g (t2). Absorbent resin particles having a ratio (t2 / t1) of 2 to 20 and a gel bed permeability at 0 psi swelling pressure of 40 polymers or more, a fatty acid ester having 8 to 30 carbon atoms, and 8 to 30 carbon atoms. A hydrophobic substance (C1), which is at least one selected from the group of fatty acids and salts thereof, aliphatic alcohols having 8 to 30 carbon atoms, and aliphatic group-containing amides having 8 to 30 carbon atoms, and organic polysiloxanes. The content of the hydrophobic substance (C2), which contains the hydrophobic substance (C2) and is present on the surface of the absorbent resin particles, is 0.001 to 0 based on the weight of the crosslinked polymer (A). .1% by weight, absorbent resin particles . The absorbent resin particle according to claim 1, wherein the time (t1) until the absorption amount reaches 2 g in the Demand Wettingity test method is 5 to 60 seconds. Claim 1 or 2 in which the hydrophobic substance (C1) is at least one selected from the group of sorbit stearic acid ester, sucrose stearic acid ester, stearic acid, Mg stearate, Ca stearate, Zn stearate, and Al stearate. The absorbent resin particles described in. The absorbent resin particles according to claim 3 , wherein the hydrophobic substance (C1) is sucrose stearic acid ester or Mg stearate. Claims 1 to 4 in which the hydrophobic substance (C2) is at least one selected from the group of polydimethylsiloxane, polyether-modified polysiloxane, carboxy-modified polysiloxane, epoxy-modified polysiloxane, amino-modified polysiloxane, and alkoxy-modified polysiloxane. The absorbent resin particle according to any one of the above items. Any of claims 1 to 5 , wherein the content of the hydrophobic substance (C1) existing inside the absorbent resin particles is 0.01 to 10.0% by weight based on the weight of the crosslinked polymer (A). The absorbent resin particles according to item 1. The total content of the hydrophobic substance (C1) and the hydrophobic substance (C2) present on the surface of the absorbent resin particles is 0.001 to 1.0% by weight based on the weight of the crosslinked polymer (A). The absorbent resin particle according to any one of claims 1 to 6. The absorbency according to any one of claims 1 to 7 , wherein the centrifugal retention amount of the physiological saline solution by the CRC test method is 25 to 36 g / g, and the absorption rate measured by the Vortex test method is 40 seconds or less. Resin particles. An absorber containing the absorbent resin particles according to any one of claims 1 to 8. The absorber according to claim 9, further comprising a fibrous material. An absorbent article comprising the absorber according to claim 9 or 10.