JP2019112527A - Absorbing resin particles, and absorber and absorbing article containing the same - Google Patents

Abstract

To provide absorbing resin particles which have such a rate pattern that an absorption rate is low in an initial period, is intermediate in a middle period, and is high in a latter period, and have high liquid-permeability of a swollen gel, and an absorbing article which prevents a problem such as rash even in a thin disposal diaper.SOLUTION: Absorbing resin particles contain a crosslinked polymer (A) of a monomer composition containing a water-soluble vinyl monomer (a1) and/or a vinyl monomer (a2) to become the water-soluble vinyl monomer (a1) by hydrolysis, and an internal crosslinking agent (b), in Demand Wettability test method, a ratio (t2/t1) of a time (t1) when an absorption amount to physiological saline per 1 g of absorbing resin particles reaches 2 g to a time (t2) when the absorption amount reaches 20 g is 2-20, and a gel bed transmission rate at 0 psi swelling pressure is 40 darcies or more.SELECTED DRAWING: None

Description

  The present invention relates to absorbent resin particles, an absorbent comprising the same, and an absorbent article.

  At present, for sanitary materials such as disposable diapers, sanitary napkins and incontinence pads, absorbent resins (Super Absorbent Polymers are abbreviated SAP) mainly composed of hydrophilic fibers such as pulp and acrylic acid (salt) as absorbents. The combination with) is widely used. From the viewpoint of improving Quality of Life (QOL) in recent years, the demand for these sanitary materials has shifted to lighter and thinner ones, and along with this, it has become desirable to reduce the amount of hydrophilic fibers used. . Therefore, it has become possible for SAP itself to be required to play the role that hydrophilic fibers have heretofore played in the absorber. For example, one important function of diapers is the diffusion of urine. In conventional absorbers, the proportion of hydrophilic fibers in the absorber is large, and the diffusion of urine is uniformly promoted in the absorber regardless of the absorption rate performance of the absorbent resin, and the absorbent resin in the absorber is effectively used. It has a usable structure. However, when the amount of hydrophilic fiber in the absorber decreases, the absorption rate of the absorbent resin is biased depending on the portion of the absorber, so that the absorber can not be effectively used, and the remaining portion of the liquid to be absorbed is It is easy to occur. Or, it tends to cause problems such as long time for which the unabsorbed liquid stays in the entire absorber.

  Therefore, absorbent resin particles are known which promote the diffusion of urine uniformly in the absorber by controlling the absorption rate of SAP even if the amount of hydrophilic fiber used is small. For example, there is an absorbent resin particle (Patent Document 1) having a structure comprising a hydrophobic substance inside a crosslinked polymer. Moreover, the absorptive resin particle which powder flowability etc. improved by making a hydrophobic substance adhere to the surface of a crosslinked polymer is known (patent document 2).

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

  When the absorbent resin particles are applied to an absorbent article (such as a disposable diaper), in the absorbent used in the absorbent article, the absorptivity of the absorbent resin is biased depending on the site of the absorbent and the absorbent is effective It can not be used to create the remaining part of the liquid to be absorbed. Or, it tends to cause problems such as long time for which the unabsorbed liquid stays in the entire absorber.

  Specifically, when the absorbent resin particles of (i) are used, the liquid is absorbed rapidly at the initial stage after contact with the absorbent resin particles at the site where the liquid to be absorbed contacts. However, when the absorbent resin particles absorb the liquid and swell to become gel-like, the unabsorbed liquid diffuses in the absorber and prevents it from being absorbed, and as a result, the portion to which the absorbed liquid contacts is absorbed The absorptivity is biased such that the absorptivity of the conductive resin particles is high and the absorptivity of the absorptive resin particles is low in the peripheral region. Then, the non-absorbed liquid tends to remain at the site where the absorbed liquid contacts.

On the other hand, when the absorbent resin particles of (ii) are used, the liquid is absorbed only gradually after contacting with the absorbent resin particles at the site where the liquid to be absorbed comes in contact, and the liquid which is not absorbed As a result, the absorptivity of the absorbent resin particles is likely to be equal between the site where the liquid to be absorbed is in contact and the area around the site. However, the overall slow absorption rate makes it possible for the unabsorbed liquid to stay longer in the entire absorber.
With these absorbent resins, there is a problem that, at the site where the unabsorbed liquid remains or at the site where the dwell time is long, a problem such as fogging tends to occur on the skin of the wearer contacting the site.

  In addition, absorbent resin particles having an absorption rate pattern (iii) initial slow, middle-term normal, and late-fast absorbent resin particles are also known by controlling the amount of hydrophobic substances on and in the surface of the absorbent resin particles (Patent Document 3). This is known to diffuse liquid throughout the diaper than the absorption rate patterns of (i) and (ii) above. However, in a thin paper diaper having a high SAP ratio, it is necessary to diffuse the liquid in the SAP gel itself because the amount of pulp for diffusing the liquid is small, and the diaper performance is not necessarily satisfied.

JP 2005-097569 Unexamined-Japanese-Patent No. 2004-261796 WO2010073658A1

  The object of the present invention is an absorbing resin particle having an initial low absorption rate, an intermediate low speed, and a late high speed, and an absorbent resin particle having a high liquid permeability of the swollen gel, and an absorption which does not cause a problem such as blurring in a thin paper diaper. It is providing a sex article.

  That is, according to the present invention, the crosslinking weight of the monomer composition containing the water soluble vinyl monomer (a1) and / or the vinyl monomer (a2) to be the water soluble vinyl monomer (a1) by hydrolysis and the internal crosslinking agent (b) Absorbent resin particles containing coalesced (A), and in the Demand Wettability test method, the absorption amount is 20 g and the time (t1) until the absorption amount with respect to physiological saline per 1 g of absorbent resin particles reaches 2 g Absorbent resin particles having a time (t2) ratio (t2 / t1) of 2 to 20 and having a gel bed permeability of 40 darcies or more at 0 psi swelling pressure; absorption comprising said absorbent resin particles An absorbent body comprising the body, in particular, the absorbent resin particles and a fibrous material; an absorbent article comprising the absorbent body.

  The present inventors solved the above-mentioned subject by absorptive resin particles which have a specific absorption rate pattern and high gel permeability. The absorbent resin particles of the present invention have a slow absorption rate at an early stage, a middle term normal stage, a late stage speed pattern, and high gel permeability. Therefore, when the absorbent resin particles of the present invention are applied to thin absorbent articles (such as disposable diapers and sanitary napkins), the absorption ratio is less biased and exhibits excellent absorption performance (absorption amount and absorption speed), It is hard to cause a rash.

  There is no particular limitation on the water-soluble vinyl monomer (a1) in the present invention, and it 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 monomers, nonionic vinyl monomers, cationic vinyl monomers), anionic vinyl monomers disclosed in paragraphs 0009 to 0024 of JP-A No. 2003-165883, nonionic vinyl Monomer, cationic vinyl monomer, at least one selected from the group consisting of carboxy group, sulfo group, phosphono group, hydroxyl group, carbamoyl group, amino group and ammonio group disclosed in paragraphs 0041 to 0051 of JP-A-2005-75982 Vinyl mono with one kind Vinyl monomers can be used in chromatography).

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

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

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

  When the monomer composition contains either a water-soluble vinyl monomer (a1) or a hydrolyzable vinyl monomer (a2) as a component, one type may be used alone as a component, and two or more types may be used as necessary. May be used as a component. The same applies to the case where the water-soluble vinyl monomer (a1) and the hydrolyzable vinyl monomer (a2) are used as constituent components. When the water-soluble vinyl monomer (a1) and the hydrolyzable vinyl monomer (a2) are used as constituent components, their content molar ratio (a1 / a2) is preferably 75/25 to 99/1, and more preferably 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 the above monomer composition, in addition to the water-soluble vinyl monomer (a1) and the hydrolyzable vinyl monomer (a2), other vinyl monomers (a3) copolymerizable therewith may be used as constituents. it can. The other vinyl monomers (a3) may be used alone or in combination of two or more.

There is no particular limitation on the copolymerizable other vinyl monomer (a3), and known vinyl monomers (for example, hydrophobic vinyl monomers disclosed in paragraphs 0028 to 0029 of Japanese Patent No. 3648553, Japanese Patent Laid-Open No. 2003-165883, The hydrophobic vinyl monomer etc. of the vinyl monomer disclosed in the paragraph 0058 of JP-A-2005-75982 can be used, and the vinyl monomers etc. of the following (i) to (iii) can be used.
(I) Aromatic ethylenic monomers having 8 to 30 carbon atoms Styrene, styrene such as α-methylstyrene, vinyl toluene and hydroxystyrene, and halogen-substituted styrenes such as vinyl naphthalene and dichlorostyrene.
(Ii) Aliphatic ethylene monomers having 2 to 20 carbon atoms: Alkenes [ethylene, propylene, butene, isobutylene, pentene, heptene, diisobutylene, octene, dodecene and octadecene etc.]; and alkadienes such as butadiene and isoprene etc.
(Iii) Alicyclic ethylene monomers having 5 to 15 carbon atoms Monoethylenically unsaturated monomers [pinene, limonene, indene etc.]; and polyethylene-like vinyl polymerizable monomers [cyclopentadiene, bicyclopentadiene, ethylidene norbornene etc.] etc.

  The content (mol%) of the other vinyl monomer (a3) units 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 etc. 0 to 5 are preferable, more preferably 0 to 3, particularly preferably 0 to 2, particularly preferably 0 to 1.5, and the content of the other vinyl monomer (a3) unit is from the viewpoint of absorption performance etc. Most preferably, it is 0 mol%.

  There is no particular limitation on the internal crosslinking agent (b), and known crosslinking agents (for example, crosslinking agents having two or more ethylenic unsaturated groups disclosed in paragraphs 0031 to 0034 of Japanese Patent No. 3648553, water-soluble substituents and Crosslinker having at least one functional group capable of reacting and having at least one ethylenically unsaturated group, crosslinker having at least two functional groups capable of reacting with a water-soluble substituent, The crosslinking agent having two or more ethylenic unsaturated groups disclosed in paragraphs 0028 to 0031 of the gazette, the crosslinking agent having an ethylenic unsaturated group and a reactive functional group, having two or more reactive substituents Crosslinking agent, Crosslinkable vinyl monomer disclosed in paragraph 0059 of JP-A-2005-75982, Paragraphs 0015 to 0016 of JP-A-2005-95759 Crosslinking agents are disclosed crosslinkable vinyl monomer) can be used. Among these, from the viewpoint of absorption properties etc., a crosslinking agent having 2 or more ethylenic unsaturated groups is preferable, more preferably poly (meth) allyl ether of a polyol having 2 to 10 carbon atoms, particularly preferably triallyl shear. Nurate, triallyl isocyanurate, tetraaryloxyethane, trimethylolpropane diallyl ether and pentaerythritol triallyl ether, most preferably pentaerythritol triallyl ether.

  The content (% by weight) of the internal crosslinking agent (b) contained in the monomer composition also uses other vinyl monomers (a3) of the water-soluble vinyl monomer (a1) and the hydrolyzable vinyl monomer (a2) In the case of (a1) to (a3) based on the total weight, it is preferably 0.05 to 0.7, 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.

  As a method for producing a crosslinked polymer (A), known aqueous solution polymerization (diathermal polymerization, thin film polymerization, spray polymerization method, 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 Publication No. 54-30710, Japanese Patent Publication No. 56-26909, Japanese Patent Publication No. 1-5808, etc.). Among the polymerization methods, preferred is a solution polymerization method, and an aqueous solution polymerization method is particularly preferable because it is unnecessary to use an organic solvent and the like and advantageous in terms of production cost.

  When a solvent (organic solvent, water, etc.) is used for the polymerization, it is preferable to evaporate the solvent after the polymerization. When the solvent contains an organic solvent, the content (% by weight) of the organic solvent after evaporation is preferably 0 to 10, more preferably 0 to 5, particularly preferably, based on the weight of the crosslinked polymer (A). Is 0-3, most preferably 0-1. Within this range, the absorption performance of the absorbent resin particles is further improved.

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

  A water-containing gel consisting of the crosslinked polymer (A) and water is obtained by aqueous solution polymerization. The obtained water-containing gel can be shredded and used as needed. The size (longest diameter) of the shredded gel 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) to be described later is easily distilled off, which is preferable.

  The shredding can be performed by a known method, and shredding can be performed using a known shredding device (for example, a Bex mill, a rubber chopper, a farm mill, a mincing machine, an impact crusher and a roll crusher), etc. .

  In addition, the content of the organic solvent and the moisture content are infrared moisture measuring instruments (JET400 manufactured by KETT Co., Ltd .: 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 of distilling off the solvent (including water), a method of distilling (drying) with hot air at a temperature of 80 to 230 ° C., a thin film drying method by a drum dryer etc. heated to 100 to 230 ° C. A vacuum drying method, a lyophilization method, an infrared ray drying method, a decantation and a filtration 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 water-containing gel may be neutralized with a base. The neutralization degree of the acid group is preferably 50 to 80 mol%. When the degree of neutralization is less than 50 mol%, the tackiness of the resulting water-containing gel polymer may be high, and the workability at the time of production and use may be deteriorated. Furthermore, the water retention amount of the water-absorbent resin particles obtained may be reduced. On the other hand, when the degree of neutralization exceeds 80%, the pH of the obtained resin may be high, which may cause the safety of the skin of the human body.
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, for example, a method such as neutralization in the state of a water-containing gel is a preferable example. It is illustrated.
As a base to be neutralized, alkali metal hydroxides such as sodium hydroxide and potassium hydroxide, and alkali metal carbonates such as sodium carbonate, sodium hydrogencarbonate and potassium carbonate can usually be used.

  The crosslinking polymer (A) may be of one type or a mixture of two or more types.

  After drying the water-containing gel to obtain a crosslinked polymer (A), it can be further pulverized. There is no particular limitation on the method of grinding, and known grinding devices (for example, a hammer type crusher, an impact type crusher, a roll crusher, and a shett air flow crusher) can be used. After grinding, if necessary, the particle size can be adjusted by sieving etc. and used.

  When the particle size adjustment is performed by sieving, the weight average particle diameter (μm) of the crosslinked polymer (A) obtained after sieving is preferably 100 to 800, more preferably 200 to 700, and further preferably 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 is determined using the low tap test sieve shaker and standard sieves (JIS Z8801-1: 2006) according to Perry's Chemical Engineer's Handbook 6th Edition (McGrow Hill Book, Inc. 1984) , Page 21). That is, JIS standard sieves are combined in the order of 1000 μm, 850 μm, 710 μm, 500 μm, 425 μm, 355 μm, 250 μm, 150 μm, 125 μm, 75 m and 45 μm from above, and the like. About 50 g of the measurement particles are placed in the uppermost sieve and shaken for 5 minutes with a low tap test sieve shaker. The weight of the measurement particles on each sieve and receiver is weighed, and the weight fraction of the particles on each sieve is determined by taking the total as 100% by weight. After plotting the weight fraction on the vertical axis), a line connecting points is drawn to obtain a particle size corresponding to 50% by weight of the weight fraction, which is defined as a weight average particle size.

  The content of the fine particles contained in the crosslinked polymer (A) is the content of the fine particles of 106 μm or less (preferably 150 μm or less) contained in the crosslinked polymer (A) from the viewpoint of absorption performance. 3 weight% or less is preferable based on the total weight of A), More preferably, it is 1 weight% or less. The content of the fine particles can be determined using the plot created when determining the above-mentioned weight average particle diameter.

  The apparent density (unit: g / ml, the same shall apply hereinafter) of the crosslinked polymer (A) is preferably 0.54 to 0.70, more preferably 0.56 to 0.65, and particularly preferably 0.58 to 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 irregularly crushed, scaly, pearly and rice grains. Among these, from the viewpoint of good interlocking with the fibrous material in paper diaper applications and the like and no concern of detachment from the fibrous material, the irregularly crushed material is preferable.

  The crosslinked polymer (A) can be subjected to surface crosslinking treatment with a surface crosslinking agent (d), if necessary. As the surface crosslinking agent (d), known ones are disclosed (JP-A-59-189103, JP-A-58-180233, JP-A-61-16903, JP-A-61-211305, JP-A Surface cross-linking agents {polyvalent glycidyl, polyvalent alcohol, polyvalent amine, polyvalent aziridine, polyvalent isocyanate, such as JP-A-61-252212, JP-A-51-136588, JP-A-61-257235, etc.} Silane coupling agents and polyvalent metals etc. can be used. Among these, polyvalent glycidyl, polyhydric alcohol and polyhydric amine are preferable, more preferably polyvalent glycidyl and polyhydric alcohol, particularly preferably polyvalent glycidyl, most preferably ethylene glycol, from the viewpoint of economy and absorption characteristics. It is diglycidyl ether.

  The amount (% by weight) of the surface crosslinking agent (d) used is not particularly limited because it can be variously changed depending on the type of the surface crosslinking agent (d), the conditions for crosslinking and the target performance, etc. From a viewpoint etc., based on the total weight of a crosslinked polymer (A), 0.03-0.5 are preferable, More preferably, it is 0.05-0.3, Especially preferably, it is 0.08-0.2. .

  The step of surface crosslinking can be carried out by mixing the crosslinking polymer (A) and the surface crosslinking agent (d) and further heating the mixture, and it is known (for example, Japanese Patent No. 3648553, JP-A No. 2003-165883). The surface crosslinking treatment method described in JP-A-2005-75982 and JP-A-2005-95759 can be used.

  As a preferred method of surface crosslinking, an aqueous solution of a surface crosslinking agent (d) was sprayed onto the surface of the crosslinked polymer (A) while stirring the crosslinked polymer (A), and then it was stirred or allowed to stand. The method of heating at 100-200 degreeC (preferably 120 degreeC-160 degreeC) in a state is mentioned. When an aqueous solution of the surface crosslinking agent (d) is sprayed onto the surface of the crosslinked polymer (A), the concentration of the surface crosslinking agent (d) contained in the aqueous solution to be sprayed is adjusted according to the type of the surface crosslinking agent (d) However, it is preferably 0.1 to 10% by weight from the viewpoint of absorption characteristics and the like. The liquid 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. In the step of surface crosslinking, spraying the aqueous solution of the surface crosslinking agent (d) onto the crosslinked polymer (A) under stirring is carried out using a known flow type humidifying and mixing granulator [flexiomix (manufactured by Hosokawa Micron Corporation) and A mixing device in which a known spray device is attached to Shugi flexomix (manufactured by Powrex Corp., etc.) and a known powder mixer [V-type mixer, Henschel mixer and turbulizer (manufactured by Hosokawa Micron Corp.), etc.] And so on.

  In the step of surface crosslinking, heating to 100 to 200 ° C. in a stirred state means that the crosslinking polymer (A) sprayed with the surface crosslinking agent is a known stirring device (double-arm kneader etc.) equipped with a heating device The reaction can be carried out by stirring with heating. Among the steps of surface crosslinking, heating to 100 to 200 ° C. in a state of standing still can be performed using a known heating drying apparatus (circulating dryer etc.). The heating time in the case of heating to 100-200 degreeC is 3 to 60 minutes normally, Preferably it is 10 to 40 minutes.

  In addition, as a method of mixing a crosslinking polymer (A) and a surface crosslinking agent (d), in addition to a method of spraying an aqueous solution of the surface crosslinking agent (d), the crosslinking polymer (A) is used as a surface crosslinking agent (d) The method of immersing in the aqueous solution of can also be used. When the crosslinked polymer (A) is immersed in an aqueous solution of the surface crosslinking agent (d), surface crosslinking can be performed by a method of heating while 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.

  As the hydrophobic substance (C1), long-chain (C8 to C30) fatty acid ester, long-chain (C8 to C30) fatty acid and salts thereof, long-chain (C8 to C30) aliphatic alcohol, long-chain (C8-C30) aliphatic group-containing amides, mixtures of two or more of these, and the like are included.

  As long-chain (C8 to C30) fatty acid esters, esters of C8 to C30 fatty acids and C1 to C12 alcohols {eg methyl laurate, ethyl laurate, methyl stearate, ethyl stearate , Methyl oleate, ethyl oleate, glycerin laurate monoester, glycerin stearic acid monoester, glycerin oleate monoester, pentaerythrite laurate monoester, pentaerythrite stearic acid monoester, pentaerythritol dioleate monoester , Sorbit lauric acid monoester, Sorbit stearic acid monoester, Sorbit oleic acid monoester, Sucrose palmitic acid monoester, Sucrose palmitic acid diester, Sucrose palmitic acid triester, Stearic acid monoester, sucrose stearic acid diester, sucrose stearic acid triester, and beef tallow} and the like.

  Examples of long chain (C8 to C30) fatty acids and salts thereof include C8 to C30 fatty acids (eg, lauric acid, palmitic acid, stearic acid, oleic acid, dimer acid and behenic acid etc.), As a salt, a salt with zinc, calcium, magnesium or aluminum (hereinafter abbreviated as Zn, Ca, Mg, Al) {eg, Ca palmitate, Al palmitate, Ca stearate, Mg stearate, Al stearate etc.} Can be mentioned.

  Examples of long chain (C8 to C30) aliphatic alcohols include C8 to C30 aliphatic alcohols {eg, lauryl alcohol, palmityl alcohol, stearyl alcohol, oleyl alcohol, etc.}. From the viewpoint of moisture resistance of the absorbent article, palmityl alcohol, stearyl alcohol and oleyl alcohol are preferable, and stearyl alcohol is more preferable.

As long-chain (C8 to C30) aliphatic group-containing amide, an amidated compound of C8 to C30 aliphatic primary amine and a C1 to C30 hydrocarbon group having a hydrocarbon group, ammonia or carbon number Amide of 1 to 7 primary amine and fatty acid having 8 to 30 carbon atoms, aliphatic secondary amine having at least one aliphatic chain having 8 to 30 carbon atoms and carboxylic acid having 1 to 30 carbon atoms Examples thereof include aliphatic group-containing amides having 8 to 30 carbon atoms such as amidated amides and amides 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 amidated compound 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, the primary amine and the carboxylic acid are reacted in a ratio of 1: 1 with 1: 2 It is divided into the ones that reacted. As a product reacted at 1: 1, acetic acid N-octylamide, acetic acid N-hexacosylamide, heptacosanoic acid N-octylamide, heptacosanoic acid N-hexacosylamide and the like can be mentioned. Examples of the reaction at 1: 2 include diacetic acid N-octylamide, diacetic acid N-hexacosylamide, diheptacosanoic acid N-octylamide, and diheptacosanoic acid N-hexacosylamide. In the case where the primary amine and the carboxylic acid are reacted at 1: 2, the carboxylic acids used may be the same or different.

  As an amidated product of ammonia or a primary amine of 1 to 7 carbon atoms and a fatty acid of 8 to 30 carbon atoms, it was reacted 1: 2 with a reaction product of ammonia or primary amine and carboxylic acid at 1: 1. It is divided into things. As a product reacted at 1: 1, 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 Etc. As reaction products at 1: 2: dinonanoic acid amide, dinonanoic acid N-methylamide, dinonanoic acid N-heptylamide, dioctadecanoic acid amide, dioctadecanoic acid N-ethylamide, dioctadecanoic acid N-heptylamide, diheptacosanoic acid amide And diheptacosanoic acid N-methylamide, diheptacosanoic acid N-heptylamide, and diheptacosanoic acid N-hexacosylamide. In addition, as a product in which ammonia or a primary amine and a carboxylic acid are reacted at 1: 2, the carboxylic acid to be used may be the same or different.

  As an amidated compound of aliphatic secondary amine having at least one aliphatic chain having 8 to 30 carbon atoms and carboxylic acid having 1 to 30 carbon atoms, acetic acid N-methyloctylamide, acetic acid N-methylhexacosylamide Acetic acid N-octylhexacosylamide, acetic acid N-dihexacosylamide, heptacosanoic acid N-methyloctylamide, heptacosanoic acid N-methylhexacosylamide, heptacosanoic acid N-octylhexacosylamide and heptacosanoic acid N -Dihexacosyl amide etc. are mentioned.

  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 is further improved. The HLB value means the hydrophilic-hydrophobic balance (HLB) value, and can be determined by the Oda method (new surfactant introduction, page 197, issued by Fujimoto Takehiko, Sanyo Chemical Industries, Ltd., 1981). .

  Sorbit stearic acid ester, sucrose stearic acid ester, stearic acid, magnesium stearate, calcium stearate, zinc stearate and aluminum stearate, among the hydrophobic substances (C1), from the viewpoint of the moisture resistance of the absorbent article Preferred are sucrose stearate and Mg stearate, and most preferred is sucrose stearate monoester.

The hydrophobic substance (C1) may be present anywhere on 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. They may be present inside and on the surface of the absorbent resin particles. Preferably, they are present at least inside the absorbent resin particles. It is preferable that the majority of the hydrophobic substance (C1) is present inside the absorbent resin particles, but a part thereof may be present on the surface. The content (% by weight) of the hydrophobic substance (C1) present in the interior of the absorbent resin particles is the cross-linked polymer (A) from the viewpoints of the anti-fake resistance of the absorbent article and the moisture resistance of the absorbent article. It is usually from 0.01 to 10.0% by weight, preferably from 0.01 to 5.0, more preferably from 0.05 to 2.0, particularly preferably from 0.1 to 1.0, based on the weight. It is.
The content (% by weight) of the hydrophobic substance (C1) present on the surface of the absorbent resin particles is the cross-linked polymer (A) from the viewpoint of the anti-fake resistance of the absorbent article and the moisture resistance of the absorbent article. 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 based on weight. .

  The structure in which the hydrophobic substance (C1) is present inside the absorbent resin particle and a part thereof is present on the surface is (1) the water-containing substance of the hydrophobic substance (C1) and the crosslinked polymer (A). It may be produced by a method of mixing and kneading with a gel, or (2) a method of obtaining a water-containing gel of a crosslinked polymer (A) by polymerizing constituent units in the presence of a hydrophobic substance (C1).

  In the method of (1), as the shape of the hydrophobic substance (C1), one obtained by processing into a crushed material, a bead, a rod or a fiber can be used. From the viewpoint of leakage resistance and the like of the absorbent article, it is preferably a crushed material or a bead, more preferably a bead. The volume average particle diameter (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 of mixing the cross-linked 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 cross-linked polymer (A). However, the hydrophobic substance (C1) is preferably mixed with the water-containing gel of (A) or the polymerization solution of (A), not the dried product of the crosslinked polymer (A), more preferably of (A) It is to be mixed with the water-containing gel. In addition, it is preferable to mix uniformly so that mixing may knead | mix.
When the crosslinked polymer (A) is obtained by the aqueous solution polymerization method, the timing of mixing and kneading the hydrophobic substance (C1) and (A) is not particularly limited, but in the presence of {(C1) in the polymerization step. , (A) is produced, immediately after the polymerization step, during crushing of the water-containing gel (mincing), during drying of the water-containing gel, and the like. Among these, from the viewpoint of leakage resistance and the like of the absorbent article, it is preferably immediately after the polymerization step and during the process of crushing (mincing) the water-containing gel, and more preferably during the process of crushing (mincing) the water-containing gel. In addition, when the hydrophobic substance (C1) is a long chain fatty acid salt, usually a long chain fatty acid salt itself is used, but long chain fatty acid and metal hydroxide may be mixed in this addition process, You may put it separately.

  When obtaining the crosslinked polymer (A) by the reverse phase suspension polymerization method or emulsion polymerization, the timing of mixing the hydrophobic substance (C1) and (A) is not particularly limited, but during the polymerization step {(C1) In the presence of (A)}, immediately after the polymerization step, during the dehydration step (in the step of dehydration to about 10% by weight of water), immediately after the dehydration step, during the step of separating and distilling off the organic solvent used for polymerization And drying of the water-containing gel. Among them, from the viewpoint of the moisture resistance of the absorbent article, etc., the step of separating and distilling off the organic solvent used in the polymerization is preferable, and more preferable, in the polymerization step, immediately after the polymerization step, in the dehydration step, immediately after the dehydration step. In the polymerization process, immediately after the polymerization process.

  When mixing during crushing or drying of the water-containing gel, as a mixing device, known devices such as a Beck mill, a rubber chopper, a farm mill, a mincing machine, an impact crusher and a roll crusher can be used. In the case of mixing in the polymerization solution, an apparatus with relatively high stirring power such as a homomixer or a biomixer can be used. Moreover, when mixing while drying the water-containing gel, a kneading apparatus 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.) immediately after the polymerization step and in the case of addition and mixing in the step of crushing the hydrogel (minch) is preferably 20 to 100, more preferably 40 to 90, and particularly preferably 50 to 80. . Within this range, uniform mixing is further facilitated, and the absorption characteristics are further improved.

  In the method of (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 polymerization liquid of the crosslinked polymer (A) (Dispersion) is preferable. If the hydrophobic substance (C1) does not easily become uniform, it can also be made uniform during the process of breaking up the water-containing gel. It can be carried out while depositing (C1) with the progress of the polymerization of (A). 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 swelling gel permeability.

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

  The position of the organic group (modification group) of the modified silicone {polyether modified polysiloxane, carboxy modified polysiloxane, epoxy modified polysiloxane, amino modified polysiloxane etc.} is not particularly limited, but the side chain of polysiloxane, polysiloxane Or both ends of the polysiloxane, one end of the polysiloxane, and both side chains and both ends of the polysiloxane. Among these, from the viewpoint of absorption properties etc., both side chains of polysiloxane and both side chains and both ends of polysiloxane are preferable, and both side chains and both ends of polysiloxane are more preferable.

  Examples of the organic group (modification group) of the polyether-modified polysiloxane include a group containing a polyoxyethylene group or a poly (oxyethylene · oxypropylene) group. 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, particularly preferably 5 to 30 per one molecule of the polyether modified polysiloxane. 7 to 20, most preferably 10 to 15. Within this range, the absorption characteristics are further improved. When the oxyethylene group and the 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. To 20. Within this range, the absorption characteristics are further improved.

The polyether-modified polysiloxane is readily available from the market, and preferred examples thereof include the following products {modification position, type of oxyalkylene}.
・ Shin-Etsu Chemical Co., Ltd. KF-945 {side chain, oxyethylene and oxypropylene}, KF-6020 {side chain, oxyethylene and oxypropylene}, X-22-6191 {side chain, oxyethylene and oxypropylene} X-22-4952 {side chain, oxyethylene and oxypropylene}, X-22-4272 {side chain, oxyethylene and oxypropylene}, X-22-6266 {side chain, oxyethylene and oxypropylene}
Toray Dow Corning Co., Ltd. FZ-2110 {both ends, oxyethylene and oxypropylene}, FZ-2122 {both ends, oxyethylene and oxypropylene}, FZ-7006 {both ends, oxyethylene and oxypropylene}, FZ-2166 {both ends, oxyethylene and oxypropylene}, FZ-2164 {both ends, oxyethylene and oxypropylene}, FZ-2154 {both ends, oxyethylene and oxypropylene}, FZ-2203 {both ends, oxy Ethylene and oxypropylene} and FZ-2207 {both ends, oxyethylene and oxypropylene}

  The organic group (modified group) of the carboxy-modified polysiloxane contains a group containing a carboxy group and the like, and the organic group (modified group) of an epoxy-modified polysiloxane contains a group containing an epoxy group etc. Examples of the organic group (modification group) of the polysiloxane include a group containing an amino group (1, 2, 3 or 4 amino group). The content (g / mol) of the organic group (modification group) of these modified silicones is preferably 200 to 11,000 as a carboxy equivalent, an epoxy equivalent or an amino equivalent, more preferably 600 to 8000, particularly preferably 1000 to 4000. It is. Within this range, the absorption characteristics are further improved. In addition, a carboxy equivalent is measured based on "16. total acid value test" of JISC2101: 1999. Moreover, epoxy equivalent is calculated | required based on JISK7236: 2001. In addition, the amino equivalent is measured in accordance with JIS K 2501: 2003 “8. Potentiometric titration method (base value / hydrochloric acid method)”.

Carboxy-modified polysiloxanes are readily commercially available, and preferred examples thereof include the following products {Modification position, carboxy equivalent (g / mol)}.
· Shin-Etsu Chemical Co., Ltd. X-22-3701 E {side chain, 4000}, X-22-162 C {both ends, 2300}, X-22-3710 {one end, 1450}
・ Toray Dow Corning KK 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 from the market, and preferred examples thereof include the following products {modification position, epoxy equivalent weight}.
-Shin-Etsu Chemical Co., Ltd. X-22-343 {side chain, 525}, KF-101 {side chain, 350}, KF-1001 {side chain, 3500}, X-22-2000 {side chain, 620} X-22-2046 {side chain, 600}, KF-102 {side chain, 3600}, X-22-4741 {side chain, 2500}, KF-1002 {side chain, 4300}, X-22-3000T {Side chain, 250}, X-22-163 {both ends, 200}, KF-105 {both ends, 490}, X-22-163 A {both ends, 1000}, X-22-163 B {both ends, 1750}, X-22-163C {both ends, 2700}, X-22-169 AS {both ends, 500}, X-22-169 B {both ends, 1700}, X-22-173 DX {one end, 4500} , X-22-9002 { Side chain, both ends, 5000}
Toray Dow Corning KK-made FZ-3720 {side chain, 1200}, BY 16-839 {side chain, 3700}, SF 8411 {side chain, 3200}, SF 8413 {side chain, 3800}, SF 8421 { Side chain, 11000}, BY 16-876 {side chain, 2800}, FZ-3736 {side chain, 5000}, BY 16-855 D {side chain, 180}, BY 16-8 {side chain, 3700}

Amino-modified silicones are readily commercially available, and preferred examples thereof include the following products {modification position, amino equivalent}.
Shin-Etsu Chemical Co., Ltd. KF-865 {side chain, 5000}, KF-864 {side chain, 3800}, KF-859 {side chain, 6000}, KF-393 {side chain, 350}, KF-860 {Side chain, 7600}, KF-880 {side chain, 1800}, KF-8004 {side chain, 1500}, KF-8002 {side chain, 1700}, KF-8005 {side chain, 11000}, KF-867 {Side chain, 1700}, X-22-3820 W {side chain, 55000}, KF-869 {side chain, 8800}, KF-861 {side chain, 2000}, X-22-3939 A {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 End, 1500 }, KF-8012 {both ends, 2200}, KF-8008 {both ends, 5700}, X-22-1660B-3 {both ends, 2200}, KF-857 {side chain, 2200}, KF-8001 { Side chain, 1900}, KF-862 {side chain, 1900}, X-22-9192 {side chain, 6500}
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 16-879 B {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 16-853 C {both End, 360}, BY 16-853 U {both ends, 450}
As a mixture of these, a mixture of polydimethylsiloxane and a carboxyl modified polysiloxane, a mixture of a polyether modified polysiloxane and an amino modified polysiloxane, etc. are mentioned.

The viscosity (mPa · s, 25 ° C.) of the hydrophobic substance (C2) is preferably 10 to 5,000, more preferably 15 to 3,000, and particularly preferably 20 to 1,500. Within this range, the absorption characteristics are further improved. In addition, a viscosity is JIS Z8803-1991 "viscosity of liquid" 9. Measured according to the viscosity measurement method using a cone and cone-plate type rotational viscometer {For example, E-type viscometer temperature-controlled to 25.0 ± 0.5 ° C (RE80L manufactured by Toki Sangyo Co., Ltd. radius 7 mm , An angle of 5.24 × 10 ⁻² rad cones). }

  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 cross-linked polymer (A) from the viewpoint of the anti-fake resistance of the absorbent article and the moisture resistance of the absorbent article. It is usually 0.001 to 1.0, preferably 0.005 to 0.1, and more preferably 0.01 to 0.05, based on weight.

  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 the powder of the hydrophobic substance (C2) and the crosslinked polymer (A) . According to this production method, usually, the hydrophobic substance (C2) is present substantially only on the surface of the absorbent resin particles.

  The method of mixing the crosslinked polymer (A) and the hydrophobic substance (C2) is not limited as long as the hydrophobic substance (C2) is mixed on the surface of the crosslinked polymer (A). The timing of mixing and kneading the hydrophobic substance (C2) and the cross-linked polymer (A) is not particularly limited, but examples include a surface cross-linking step after drying of the water-containing gel and a post-treatment after surface cross-linking. Among these, the surface crosslinking step is preferable from the viewpoint of the moisture resistance of the absorbent article and the like. When the hydrophobic substance (C2) is a hydrophobic substance having a functional group-modified polysiloxane structure, one modified body may be added, or a plurality of modified bodies may be mixed and added. .

  In the resin particle of the present invention, the hydrophobic substance present on the surface may generally be (C1) alone, or (C2) alone when (C2) is used in combination, Since a part of (C1) added may bleed 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) present inside is the total added amount of the hydrophobic substance minus the content of the hydrophobic substance on the surface.

<Method of measuring the content of hydrophobic substance (C1) + (C2) on the surface>
100 parts by weight of absorbent resin particles and 300 parts by weight of n-hexane are added to a glass-made eggplant flask equipped with a cooling pipe, and left at a dissolution temperature for 24 hours to obtain an extract of a hydrophobic substance. The extract is filtered using a filter paper and collected in a preweighed glass eggplant flask, and then the solvent is evaporated by a rotary evaporator and then weighed. The weight of the pre-weighed eggplant flask is subtracted from the weight after evaporation of the filtrate to determine the amount of the evaporated extract extracted.
The same operation is repeated twice using the sample after extraction remaining on the filter paper, and the total amount of the evaporated matter obtained by extraction three times is the total amount of hydrophobic substances (C1) and (C2) of the surface. 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), from the viewpoint of availability and solubility, inorganic acid salts of aluminum and inorganic acid salts of titanium are preferable, and aluminum sulfate, aluminum chloride, potassium aluminum sulfate and sulfuric acid are more preferable. Sodium aluminum, particularly preferred is aluminum sulfate and sodium aluminum sulfate, most preferred is sodium aluminum sulfate. One of these may be used alone, or two or more may be used in combination.

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

  When the absorbent resin particles of the present invention contain a polyvalent metal salt (e), the step of mixing with the polyvalent metal salt (e) is performed before the surface crosslinking step, after the surface crosslinking step, and on the surface It can be carried out simultaneously with the step of crosslinking.

As a mixing method of polyvalent metal salt (e), a cylindrical mixer, a screw mixer, a screw extruder, a turbulizer, a Nauta mixer, a double arm kneader, a fluid mixer, a V-type mixer Examples of the method include uniform mixing using a known mixing device such as a machine, a mince mixer, a ribbon mixer, a fluid mixer, a gas mixer, a rotary disk mixer, a conical blender, and a roll mixer.
When mixing before or after the step of surface crosslinking, the temperature at the time of mixing is not particularly limited, but it is preferably 10 to 150 ° C, more preferably 20 to 100 ° C, and particularly preferably 25 to 80 ° C.
When mixing simultaneously with the step of surface crosslinking, the temperature at the time of mixing is not particularly limited, but it can be carried out under the same conditions as the step of surface crosslinking with the surface crosslinking agent (d).
After carrying out 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), whereby the blocking resistance and 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 preferred and more preferred from the viewpoint of easy availability and handling and absorption performance. Is colloidal silica. The water-insoluble inorganic particles (f) may be used alone or in combination of two or more.

  The amount (% by weight) of the water-insoluble inorganic particles (f) is preferably from 0.01 to 5, more preferably from 0.05 to 1, particularly preferably from 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 performed in the same manner as the mixing of the polyvalent metal salt (e). And the conditions are similar.

  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 above-described particle size adjustment, and the particle size after particle size adjustment is also the same.

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

  In addition, the absorbent resin particles of the present invention preferably have a pH of 5.80 to 7.20 when containing 0.5% by weight based on the weight of the physiological saline. More preferably, it is 80 to 6.50. Within this range, it is preferable because it becomes weakly acidic and less likely to cause run-out.

The absorbent resin particle of the present invention has a time (t1) until the absorption reaches 2 g and a time until the absorption reaches 20 g, which are measured by the Demand Wettability test method (hereinafter, also referred to as DW test). The ratio (t2 / t1) of t2) 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 and the leakability is deteriorated, the dryability of the diaper is lost, and a rash and the like easily occur. When t2 / t1 exceeds 20, spot absorption at the urine absorption site is likely to occur and the leakability is deteriorated.
In addition, the gel bed permeability (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. If the GBP is less than 40 darcies, the diffusion of urine is inhibited by the swelling gel in a thin paper diaper having a high SAP ratio even if t2 / t1 is in the range of 2 to 20, and the leakability is deteriorated.
The ratio (t2 / t1) of time (t2) until absorption reached 20 g until absorption reached 2 g measured by DW test is 2 to 20, and the pressure at 0 psi swelling pressure Absorbent resin particles having a gel bed permeability (hereinafter, also referred to as GBP) of 40 darcies or more stably show excellent absorption performance (liquid diffusivity, absorption speed) under any load and no load under any load. And the absorption amount), and the anti-crash resistance of the absorbent article is improved.

  The absorbent resin particles of the present invention preferably have a time (t1) of 5 seconds to 60 seconds until the absorption amount reaches 2 g in the Demand Wettability test method. It is preferable to satisfy this condition because uneven gel swelling at the absorption site is suppressed.

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

  Gel bed permeability (GBP) at 0 psi swelling pressure, absorption rate under no load measured by the Demand Wettability test method, centrifugal holding capacity by the CRC test method, and absorption speed measured by the Vortex test method are 25 ± The temperature is measured in the room at 2 ° C. and 50 ± 10% humidity by the following method. The temperature of physiological saline to be used is adjusted to 25 ° C. ± 2 ° C. in advance.

<Absorption speed under no load measured by Demand Wettability test>
The absorption amount (ml / g) from the start of water absorption is 2.0 when measured by the DW method described in JP-A-2014-005472 using 0.50 g of the absorbent resin particles and physiological saline. The time it takes to achieve is the absorption speed under no load measured in the Demand Wettability test. The DW test is to determine the suction capacity of the absorbent resin under no load on a measurement table connected to the burette and the conduit.

<Gel bed permeability test at swelling pressure at 0 psi>
Measured according to the GBP test method at 0 psi swelling pressure described in Patent No. 5236668 (unit: [darcies]). In addition, it means that it is excellent in the absorption speed of absorptive resin particles, and the liquid permeability between swelling gel, so that GBP is high.

<The amount of centrifugal retention of saline>
It is measured according to the CRC test method (Centrifuge retention capacity test method) described in Japanese Patent No. 5236668, and 0.200 g of absorbent resin particles is not contained in physiological saline (0.9 mass% sodium chloride aqueous solution). Allow free swelling under pressure for 30 minutes, then drain with centrifuge (290 G, 3 minutes), amount of physiological saline retained by absorbent resin particles even after draining (physiology retained per gram of resin particles) Measure the amount of saline solution: unit; [g / g]). In addition, it means that the water absorption performance of an absorptive resin particle is high, so that CRC is high.

<Absorption rate measured by Vortex test>
2.000 g of absorbent resin particles were required until absorption of 50 g of physiological saline stirred at a rotational speed of 600 times per minute in a 100 ml tall beaker with a flat bottom as defined in JIS R 3503 The time (unit: second) is measured in accordance with JIS K 7224-1996, and is taken as the absorption rate measured by 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. . When it is in this range, the anti-crash resistance of the absorbent article is further improved. 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 irregularly crushed, scaly, pearly and rice grains. Among these, from the viewpoint of good interlocking with the fibrous material in paper diaper applications and the like and no concern of detachment from the fibrous material, the irregularly crushed material is preferable.

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.
Other materials preferably include fibrous materials. The structure, manufacturing method and the like of the absorber when used together with the fibrous material are the same as those of known ones (Japanese Patent Application Laid-Open Nos. 2003-225565, 2006-131767, and 2005-097569). is there.

  Preferred as the fibrous material are cellulose fibers, organic synthetic fibers, and a mixture of cellulose fibers and organic synthetic fibers.

  Examples of cellulosic fibers include natural fibers such as fluff pulp, and cellulosic chemical fibers such as viscose rayon, acetate and cupra. There are no particular limitations on the raw materials (softwood and hardwoods, etc.) of this cellulose-based natural fiber, the production method (chemical pulp, semichemical pulp, mechanical pulp, CTMP, etc.) and the bleaching method.

  Examples of organic synthetic fibers include polypropylene fibers, polyethylene fibers, polyamide fibers, polyacrylonitrile fibers, polyester fibers, polyvinyl alcohol fibers, polyurethane fibers and heat fusible composite fibers (the above-mentioned fibers having different melting points) Fibers in which at least two of them are combined with a sheath-core type, eccentric type, parallel type, etc., fibers obtained by blending at least two of the above fibers, and fibers obtained by modifying the surface layer of the above fibers).

  Among these fibrous materials, preferred are cellulose-based natural fibers, polypropylene-based fibers, polyethylene-based fibers, polyester-based fibers, heat-sealable composite fibers and mixed fibers thereof, and more preferred are fibers obtained It is a fluff pulp, a heat-fusible composite fiber, and a mixed fiber thereof in that it is excellent in the shape-retaining property after water absorption of the water-absorbing agent.

  The length and the thickness of the fibrous material are not particularly limited, and can be suitably 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 also not particularly limited as long as it is fibrous, and thin cylindrical, split yarn, staple, filament, web and the like are exemplified.

  In the case of the absorbent comprising the above-mentioned absorbent resin particles and fibrous material, the weight ratio of the absorbent resin particles to the fibrous material (weight of absorbent resin particles / weight of fibrous material) is 40/60. It is preferably 90/10, more preferably 70 / 30-80 / 20.

  The absorber of the present invention comprises the above-mentioned absorbent resin particles. The absorber of the present invention may be an absorber formed of an absorbent resin particle alone, or an absorber formed of an absorbent resin particle and a fibrous material. The absorber of the present invention can be used as an absorbent article. As absorbent articles, not only sanitary goods such as disposable diapers and sanitary napkins, but also various applications such as absorption and retention agent applications of various aqueous liquids, gelling agent applications (for example, pet urine absorbent, urine gel of portable toilets Agents, freshness keeping agents for fruits and vegetables, drip absorbers for meats and fish and shellfishes, cold insulators, disposable warmers, gelling agents for batteries, water retention agents for plants and soils, anti-condensing agents, water blocking agents, packing materials, artificial snow Etc.) are applicable. The manufacturing method of an absorbent article etc. are the same as that of a well-known thing (The thing as described in Unexamined-Japanese-Patent No. 2003-225565, Unexamined-Japanese-Patent No. 2006-131767, Unexamined-Japanese-Patent No. 2005-097569 etc.).

  EXAMPLES The present invention will be further described by the following Examples and Comparative Examples, but the present invention is not limited thereto.

Example 1
135 parts of acrylic acid (Mitsubishi Chemical Co., Ltd., purity 100%, the same shall apply hereinafter), 0.51 parts of pentaerythritol triallyl ether (made by Daiso-Inc., hereinafter the same), and 479 parts of deionized water It was kept at 3 ° C. while stirring and mixing. After nitrogen is introduced into this mixture to make the dissolved oxygen content 1 ppm or less, 0.5 part of 1% aqueous hydrogen peroxide solution, 1 part of 2% aqueous ascorbic acid solution and 2% 2,2'-azobisamidinopropane 0.3 part of aqueous dihydrochloride solution was added and mixed to start polymerization. After the temperature of the mixture reached 80 ° C., polymerization was carried out at 80 ± 2 ° C. for about 5 hours to obtain hydrogel (1).

  Next, 180 parts of a 30% aqueous solution of sodium hydroxide was added while continuously shredding the whole water-containing gel (1) obtained with a mincing machine (12VR-400K manufactured by ROYAL), and then the hydrophobic substance (C1-1) 0.06 parts of sucrose stearate was added and mixed and neutralized to obtain a chopped gel. Further, the chopped gel was dried by a vented 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), and then sieved to adjust to a particle diameter range of 710 to 150 μm to obtain a resin particle (B1).

  10% water of ethylene glycol diglycidyl ether (Denacol EX-810, manufactured by Nagase Chemical Industries, Ltd.) while stirring 100 parts of the obtained resin particles (B1) at high speed (high speed stirring turbulizer made by Hosokawa Micron: rotation speed 2000 rpm) : 1.4 parts of a mixed solution of methanol / methanol (water: methanol is 70:30) and 0.004 parts of hydrophobic substance (C2-1) carboxy modified polysiloxane (manufactured by Shin-Etsu Chemical Co., Ltd.) while spraying In addition, they were mixed and allowed to stand at 140 ° C. for 30 minutes in a circulating dryer (manufactured by Tabai Espec Corp.) for surface crosslinking 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
Change "0.51 part of pentaerythritol triallyl ether" to "0.68 part of pentaerythritol triallyl ether", "479 parts of deionized water", "365 parts of deionized water", "hydrophobic substance (C1 -1) 0.06 parts of sucrose stearate, "hydrophobic substance (C1-2) 0.135 parts of Mg stearate", "ethylene glycol diglycidyl ether (manufactured by Nagase Chemical Industries, Ltd., Denacol EX- 10) of a 10% water / methanol mixed solution (water: methanol mixing ratio is 70:30) 1.4 parts and a hydrophobic substance (C2-1) carboxy-modified polysiloxane (manufactured by Shin-Etsu Chemical Co., Ltd.) 0.004 10% water / methanol mixed solution of ethylene glycol diglycidyl ether (Denacol EX-810, manufactured by Nagase Chemical Industries, Ltd.) Example 1 except that the mixing ratio of water: methanol was changed to 1.6 parts by 70:30 and 0.013 parts by weight of hydrophobic substance (C2-1) carboxy-modified polysiloxane (manufactured by Shin-Etsu Chemical Co., Ltd.) In the same manner as in the above, the absorbent resin particles (2) of the present invention were obtained. 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
Change "0.51 part of pentaerythritol triallyl ether" to "0.08 part of pentaerythritol triallyl ether", "479 parts of deionized water", "287 parts of deionized water,""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 (Denacol EX manufactured by Nagase Chemicals Industries Co., Ltd.) 1.4 parts of a 10% water / methanol mixed solution (water: methanol mixture ratio is 70:30) and a hydrophobic substance (C2-1) carboxy-modified polysiloxane (manufactured by Shin-Etsu Chemical Co., Ltd.) 0. 004 parts of “ethylene glycol diglycidyl ether (manufactured by Nagase Chemical Industries, Ltd., Denacol EX-810) in 10% water / Other than changing to 1.8 parts of tanol mixed solution (water: methanol mixture ratio is 70:30) and 0.035 parts of hydrophobic substance (C2-1) carboxy modified polysiloxane (made by Shin-Etsu Chemical Co., Ltd.) In the same manner as in Example 1, an absorbent resin particle (3) of the present invention was obtained. 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
"Hydrophobic substance (C1-1) 0.06 part of sucrose stearic acid ester""Hydrophobic substance (C1-2) 0.135 part of Mg stearate", "ethylene glycol diglycidyl ether (Nagase Kasei Kogyo Co., Ltd. Ltd., Denacol EX-810) in 10% water / methanol mixed solution (water: methanol mixture ratio 70:30) 1.4 parts and hydrophobic substance (C2-1) carboxy modified polysiloxane (Shin-Etsu Chemical Co., Ltd. stock Of ethylene glycol diglycidyl ether (Denacol EX-810, manufactured by Nagase Chemical Industry Co., Ltd.) in a 10% water / methanol mixed solution (water: methanol mixing ratio is 70:30) 1.9 Part and hydrophobic substance (C2-2) amino-modified polysiloxane (manufactured by Shin-Etsu Chemical Co., Ltd.) 0.035 parts In the like, to obtain absorbent resin particles of the present invention (4). Further, the hydrophobic substance (C) was present at 0.062% inside the absorbent resin particles (4), and the hydrophobic substance (C) was present at 0.041% 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
Change "0.51 part of pentaerythritol triallyl ether" to "0.68 part of pentaerythritol triallyl ether", "479 parts of deionized water", "365 parts of deionized water", "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 (Denacol EX manufactured by Nagase Chemicals Industries Co., Ltd.) 1.4 parts of a 10% water / methanol mixed solution (water: methanol mixture ratio is 70:30) and a hydrophobic substance (C2-1) carboxy-modified polysiloxane (manufactured by Shin-Etsu Chemical Co., Ltd.) 0. 004 parts of “ethylene glycol diglycidyl ether (manufactured by Nagase Chemical Industries, Ltd., Denacol EX-810) Except that it is changed to 1.3 parts of a mixed solution of phenol (water: methanol is 70:30) and 0.004 parts of hydrophobic substance (C2-2) amino-modified polysiloxane (manufactured by Shin-Etsu Chemical Co., Ltd.) In the same manner as in Example 1, an absorbent resin particle (5) of the present invention was obtained. In addition, 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
Change “0.51 part of pentaerythritol triaryl ether” to “0.44 part of pentaerythritol triaryl ether”, “479 parts of deionized water”, “287 parts of deionized water,” “ethylene glycol diglycidyl ether 1.4 parts of a 10% water / methanol mixed solution (water: methanol mixing ratio is 70:30) of (Nagase Chemical Industries, Ltd., Denacol EX-810) and a hydrophobic substance (C2-1) carboxy-modified polysiloxane ( A 10% water / methanol mixed solution (water: methanol mixture ratio is 70:30) of “0.004 parts” (manufactured by Shin-Etsu Chemical Co., Ltd.) “ethylene glycol diglycidyl ether (Denacol EX-810 manufactured by Nagase Chemical Industries, Ltd.) ) 1.5 parts and hydrophobic substance (C2-2) amino modified polysiloxane (made by Shin-Etsu Chemical Co., Ltd.) Was changed to 0.013 parts "in the same manner as in Example 1 to obtain an absorbent resin particles of the present invention (6). 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
Change "0.51 part of pentaerythritol triallyl ether" to "0.68 part of pentaerythritol triallyl ether" and "0.06 part of hydrophobic substance (C1-1) sucrose stearic acid ester" Hydrophobic substance (C1-1) 0.338 parts of sucrose stearate, "10% water / methanol mixed solution of ethylene glycol diglycidyl ether (Denacol EX-810, manufactured by Nagase Chemical Industries, Ltd.) (water: methanol) The mixing ratio of 70:30) and hydrophobic substance (C2-1) carboxy modified polysiloxane (made by Shin-Etsu Chemical Co., Ltd.) 0.004 parts 10% water / methanol mixed solution of Denacol EX-810) (water: methanol mixing ratio is 70:30) Absorbent resin of the present invention in the same manner as in Example 1 except that 1.7 parts and the hydrophobic substance (C2-3) epoxy-modified polysiloxane (manufactured by Shin-Etsu Chemical Co., Ltd.) were changed to 0.035 parts ". Particles (7) were obtained. 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
Change "0.51 part of pentaerythritol triallyl ether" to "0.81 part of pentaerythritol triallyl ether" and "0.06 part of hydrophobic substance (C1-1) sucrose stearic acid ester" Hydrophobic substance (C1-2) 0.06 parts of Mg stearate, "479 parts of deionized water", "365 parts of deionized water", "ethylene glycol diglycidyl ether (manufactured by Nagase Chemical Industries, Ltd., Denacol EX- 10) of a 10% water / methanol mixed solution (water: methanol mixing ratio is 70:30) 1.4 parts and a hydrophobic substance (C2-1) carboxy-modified polysiloxane (manufactured by Shin-Etsu Chemical Co., Ltd.) 0.004 10% water / methanol mixed solution of “ethylene glycol diglycidyl ether (Denacol EX-810, manufactured by Nagase Chemical Industries, Ltd.)” Example 1 except that the mixing ratio of water: methanol was changed to 1.7 parts of 70:30 and the hydrophobic substance (C2-3) epoxy modified polysiloxane (manufactured by Shin-Etsu Chemical Co., Ltd.) 0.004 parts The absorbent resin particles (8) of the present invention were obtained in the same manner as in the above. 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 stearic acid ester", "0.20 part of hydrophobic substance (C1-3) Sorbit stearic acid ester", "479 parts of deionized water" 287 parts of deionized water, “1.4% of a 10% water / methanol mixed solution of ethylene glycol diglycidyl ether (Denacol EX-810, manufactured by Nagase Chemical Industries, Ltd.) (water: methanol ratio is 70:30) and 10% water / methanol of "ethylene glycol diglycidyl ether (Denacol EX-810, manufactured by Nagase Chemical Industries, Ltd.)" of 0.004 parts of hydrophobic substance (C2-1) carboxy modified polysiloxane (manufactured by Shin-Etsu Chemical Co., Ltd.) 1.8 parts of mixed solution (water: methanol ratio is 70:30) and hydrophobic substance (C2-3) epoxy modified polysiloxane (Shin-Etsu Was changed to Manabu Kogyo Co., Ltd.) 0.013 parts "in the same manner as in Example 1 to obtain an absorbent resin particles of the present invention (9). In addition, 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
Change "0.51 part of pentaerythritol triallyl ether" to "0.88 part of pentaerythritol triallyl ether" and "0.06 part of hydrophobic substance (C1-1) sucrose stearic acid ester" Hydrophobic substance (C1-3) 0.135 parts of sorbite stearic acid ester ", 10% water / methanol mixed solution (water: methanol) of ethylene glycol diglycidyl ether (Denacol EX-810, manufactured by Nagase Chemical Industries, Ltd.) "Ethylene glycol diglycidyl ether (Nagase Kasei Kogyo Co., Ltd.) made of a mixing ratio of 70 parts) and 1.4 parts of a hydrophobic substance (C2-1) carboxy modified polysiloxane (made by Shin-Etsu Chemical Co., Ltd.)" , Denacol EX-810) in 10% water / methanol mixed solution (water: methanol mixing ratio is 70: 0) 1.5 parts and hydrophobic substance (C2-1) carboxy modified polysiloxane (made by Shin-Etsu Chemical Co., Ltd.) 0.004 part and hydrophobic substance (C2-4) polyether modified polysiloxane 0.0004 part The absorbent resin particles (10) of the present invention were obtained in the same manner as in Example 1 except that they were changed to 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
"Hydrophobic substance (C1-1) 0.06 parts of sucrose stearic acid ester", "Hydrophobic substance (C1-1) 0.338 parts of sucrose stearic acid ester", "479 parts of deionized water" “Deionized water 365 parts”, “ethylene glycol diglycidyl ether (Denacol EX-810, manufactured by Nagase Chemical Industries, Ltd.) 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 Co., Ltd.) 0.004 parts "of 10% water / ethylene glycol diglycidyl ether (manufactured by Nagase Chemical Industries, Ltd., Denacol EX-810) Methanol mixed solution (water: methanol mixture ratio is 70:30) 1.8 parts and hydrophobic substance (C2-1) carboxy modified polysiloxane (Shin-Etsu Absorbent resin particles of the present invention in the same manner as in Example 1 except that 0.013 parts by Gakuin Kogyo Co., Ltd. and 0.0013 parts by weight of a hydrophobic substance (C2-4) polyether-modified polysiloxane were used. I got (11). 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
Change "0.51 part of pentaerythritol triallyl ether" to "0.68 part of pentaerythritol triallyl ether" and "0.06 part of hydrophobic substance (C1-1) sucrose stearic acid ester" Hydrophobic substance (C1-2) 0.06 parts of Mg stearate, "479 parts of deionized water", "287 parts of deionized water", "Hydrophobic substance (C2-1) carboxy modified polysiloxane (Shin-Etsu Chemical Co., Ltd.)""Manufactured by Kogyo Co., Ltd., 0.004 parts", "hydrophobic substance (C2-1) carboxy modified polysiloxane (made by Shin-Etsu Chemical Co., Ltd.) 0.035 parts 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 ratio 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
Change "0.51 part of pentaerythritol triallyl ether" to "0.68 part of pentaerythritol triallyl ether" and "0.06 part of hydrophobic substance (C1-1) sucrose stearic acid ester" Hydrophobic substance (C1-3) 0.06 parts of Sorbit stearic acid ester, "10% water / methanol mixed solution of ethylene glycol diglycidyl ether (Denacol EX-810, manufactured by Nagase Chemical Industries, Ltd.) (water: methanol) "Ethylene glycol diglycidyl ether (Nagase Kasei Kogyo Co., Ltd.) made of a mixing ratio of 70 parts) and 1.4 parts of a hydrophobic substance (C2-1) carboxy modified polysiloxane (made by Shin-Etsu Chemical Co., Ltd.)" , Denacol EX-810) in 10% water / methanol mixed solution (water: methanol mixing ratio is 70: 3) ) 2.0 parts and hydrophobic substance (C2-2) amino-modified polysiloxane (made by Shin-Etsu Chemical Co., Ltd.) 0.013 parts and hydrophobic substance (C2-4) polyether-modified polysiloxane 0.0013 parts " An absorbent resin particle (13) of the present invention was obtained in the same manner as in Example 1 except for the change. 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
Change "0.51 part of pentaerythritol triallyl ether" to "0.88 part of pentaerythritol triallyl ether" and "0.06 part of hydrophobic substance (C1-1) sucrose stearic acid ester" Hydrophobic substance (C1-1) 0.135 parts of sucrose stearate, "479 parts of deionized water", "365 parts of deionized water", "ethylene glycol diglycidyl ether (Denacol, manufactured by Nagase Chemical Industries, Ltd.) EX-810) in 10% water / methanol mixed solution (water: methanol mixture ratio 70:30) 1.4 parts and hydrophobic substance (C2-1) carboxy modified polysiloxane (made by Shin-Etsu Chemical Co., Ltd.) 0 10% water / methanoe of “ethylene glycol diglycidyl ether (Denacol EX-810, manufactured by Nagase Chemical Industries, Ltd.)” Solution (water: methanol mixture ratio is 70:30) 1.4 parts and hydrophobic substance (C2-2) amino modified polysiloxane (made by Shin-Etsu Chemical Co., Ltd.) 0.035 parts and hydrophobic substance (C2) 4) Absorbent resin particles (13) of the present invention were obtained in the same manner as in Example 1 except that the amount of the polyether modified polysiloxane was changed to 0.0035 parts. In addition, 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
"Dehydrophobic substance (C1-1) 0.06 parts of sucrose stearic acid ester", "hydrophobic substance (C1-2) Mg stearate of 0.33 parts", and "479 parts of deionized water" 287 parts of ion water, "1.4 parts of a 10% water / methanol mixed solution (water: methanol mixture ratio is 70:30) of 10% water / methanol mixed solution of ethylene glycol diglycidyl ether (Denacol EX-810, manufactured by Nagase Chemical Industries, Ltd.) and hydrophobicity Substance (C2-1) carboxy modified polysiloxane (made by Shin-Etsu Chemical Co., Ltd.) 0.004 part "of ethylene glycol diglycidyl ether (made by Nagase Chemical Industries, Ltd., Denacol EX-810) mixed with 10% water / methanol Solution (water: methanol mixture ratio is 70:30) 1.6 parts and hydrophobic substance (C2-2) amino-modified polysiloxane (Shin-Etsu Chemical Co., Ltd. Manufactured in the same manner as in Example 1 except that the amount of the hydrophobic resin (C2-4) and the hydrophobic substance (C2-4) polyether modified polysiloxane was 0.0004 parts. Obtained. 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
Change "0.51 part of pentaerythritol triallyl ether" to "0.88 part of pentaerythritol triallyl ether" and "0.06 part of hydrophobic substance (C1-1) sucrose stearic acid ester" Hydrophobic substance (C1-2) 0.338 parts of Mg stearate, "10% water / methanol mixed solution (water: methanol) of ethylene glycol diglycidyl ether (Denacol EX-810, manufactured by Nagase Chemical Industries, Ltd.) “Ethylene glycol diglycidyl ether (manufactured by Nagase Chemical Industries, Ltd.), a ratio of 70:30) and 1.4 parts of a hydrophobic substance (C2-1) carboxy-modified polysiloxane (manufactured by Shin-Etsu Chemical Co., Ltd.)” 1.4 parts of a 10% water / methanol mixture solution of Denacol EX-810) (the mixing ratio of water: methanol is 70:30) And hydrophobic substance (C2-3), epoxy modified polysiloxane (made by Shin-Etsu Chemical Co., Ltd.) 0.013 part and hydrophobic substance (C2-4) polyether modified polysiloxane 0.0013 part In the same manner as Example 1, an absorbent resin particle (16) of the present invention was obtained. 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 stearic acid ester", "0.06 parts of hydrophobic substance (C1-3) Sorbit stearic acid ester", "479 parts of deionized water" Deionized water 365 parts, “ethylene glycol diglycidyl ether (Denacol EX-810, manufactured by Nagase Chemical Industries, Ltd.) 10% water / methanol mixed solution (water: methanol mixing ratio is 70:30) 1.4 parts and 10% water / methanol of "ethylene glycol diglycidyl ether (Denacol EX-810, manufactured by Nagase Chemical Industries, Ltd.)" of 0.004 parts of hydrophobic substance (C2-1) carboxy modified polysiloxane (manufactured by Shin-Etsu Chemical Co., Ltd.) 1.6 parts of mixed solution (water: methanol ratio is 70:30) and hydrophobic substance (C2-3) epoxy modified polysiloxane (Shin-Etsu Absorbent resin particles of the present invention in the same manner as in Example 1 except that it was changed to 0.035 parts by Kagaku Kogyo Co., Ltd. and 0.0035 parts by weight of a hydrophobic substance (C2-4) polyether modified polysiloxane ". I got (17). 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
"Dehydrophobic substance (C1-1) 0.06 parts of sucrose stearate", "hydrophobic substance (C1-2) 0.135 parts of stearic acid Mg", "Deionized water 479 parts" 287 parts of ion water, "1.4 parts of a 10% water / methanol mixed solution (water: methanol mixture ratio is 70:30) of 10% water / methanol mixed solution of ethylene glycol diglycidyl ether (Denacol EX-810, manufactured by Nagase Chemical Industries, Ltd.) and hydrophobicity Substance (C2-1) carboxy modified polysiloxane (made by Shin-Etsu Chemical Co., Ltd.) 0.004 part "of ethylene glycol diglycidyl ether (made by Nagase Chemical Industries, Ltd., Denacol EX-810) mixed with 10% water / methanol 1.8 parts of solution (mixture ratio of water: methanol is 70:30) and hydrophobic substance (C2-3) epoxy modified polysiloxane (Shin-Etsu Chemical Co., Ltd. stock Absorbent resin particles (18) of the present invention in the same manner as in Example 1 except that the product is changed to 0.004 parts manufactured by I got In addition, 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
Change “hydrophobic substance (C1-1) sucrose stearic acid ester to 0.06 parts” to “hydrophobic substance (C1-1) sucrose stearic acid ester to 0 parts”, “479 parts of deionized water” 10% water / methanol mixed solution (water: methanol mixing ratio is 70:30) and 1.4% of “deionized water 287 parts”, “ethylene glycol diglycidyl ether (Denacol EX-810, manufactured by Nagase Chemical Industries, Ltd.) 10% water of “ethylene glycol diglycidyl ether (Denacol EX-810, manufactured by Nagase Chemical Industries, Ltd.)” and “hydrophobic substance (C2-1) carboxy modified polysiloxane (manufactured by Shin-Etsu Chemical Co., Ltd.) 0.004 parts” 1.8 parts of a mixed solution of methanol / methanol (water: methanol ratio is 70:30) and hydrophobic substance (C2-1) carboxy modified polysiloxane (Shin-Etsu Except that the academic Kogyo Co., Ltd.) 0 parts "in the same manner as in Example 1 to obtain absorbent resin particles of Comparative Example (19). 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” to “0.06 parts of“ hydrophobic substance (C1-1) sucrose stearate ”” “hydrophobic substance (C1-1) 0.135 parts of sucrose stearate, 0.51 parts of "pentaerythritol triaryl ether" to "0.68 parts of pentaerythritol triaryl ether", "ethylene glycol diglycidyl ether (manufactured by Nagase Chemical Industries, Ltd.) 1.4 parts of a 10% water / methanol mixture solution of Denacol EX-810) (water: methanol mixture ratio is 70:30) and a hydrophobic substance (C2-1) carboxy-modified polysiloxane (manufactured by Shin-Etsu Chemical Co., Ltd.) “0.004 parts” of “ethylene glycol diglycidyl ether (manufactured by Nagase Chemical Industries, Ltd., Denacol EX-810) in 10% water / meta Of the mixed solution (water: methanol mixture ratio is 70:30), and 1.6 parts of hydrophobic material (C2-1) carboxy modified polysiloxane (made by Shin-Etsu Chemical Co., Ltd.) 0 parts ". The absorbent resin particles (20) of Comparative Example were obtained in the same manner as Example 1. 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
Change "hydrophobic substance (C1-1) sucrose stearic acid ester to 0.06 parts" to "hydrophobic substance (C1-1) sucrose stearic acid ester to 0 parts", and "pentaerythritol triaryl ether 0 From 50 parts of “pentaerythritol triallyl ether 0.88 parts”, “10% water / methanol mixed solution (water: methanol) of ethylene glycol diglycidyl ether (Denacole EX-810, manufactured by Nagase Chemical Industries, Ltd.) “Ethylene glycol diglycidyl ether (manufactured by Nagase Chemical Industries, Ltd.), a ratio of 70:30) and 1.4 parts of a hydrophobic substance (C2-1) carboxy-modified polysiloxane (manufactured by Shin-Etsu Chemical Co., Ltd.)” 10% water / methanol mixed solution of Denacol EX-810) (water: methanol mixing ratio is 70:30) 1.7 And a hydrophobic substance (C2-1) carboxy-modified polysiloxane (manufactured by Shin-Etsu Chemical Co., Ltd.) in the same manner as in Example 1 except that 0.013 parts of the modified resin particle (21) of the comparative example was used. Obtained. 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
Change "hydrophobic substance (C1-1) sucrose stearic acid ester to 0.06 parts" to "hydrophobic substance (C1-2) Mg stearate 0.675 parts", and "pentaerythritol triaryl ether 0" From 50 parts of "pentaerythritol triallyl ether", "10% water / methanol mixture solution of ethylene glycol diglycidyl ether (Denacol EX-810, manufactured by Nagase Chemical Industries, Ltd.) (water: methanol)". “Ethylene glycol diglycidyl ether (manufactured by Nagase Chemical Industries, Ltd.), a ratio of 70:30) and 1.4 parts of a hydrophobic substance (C2-1) carboxy-modified polysiloxane (manufactured by Shin-Etsu Chemical Co., Ltd.)” 1.5 parts of a 10% water / methanol mixture solution of Denacol EX-810) (the mixing ratio of water: methanol is 70:30) And was except that in the same manner as in Example 1 to obtain absorbent resin particles of Comparative Example (22). In addition, 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
Change "hydrophobic substance (C1-1) sucrose stearic acid ester to 0.06 parts" to "hydrophobic substance (C1-1) sucrose stearic acid ester to 0 parts", and "pentaerythritol triaryl ether 0 From 50 parts of “pentaerythritol triallyl ether 0.88 parts”, “10% water / methanol mixed solution (water: methanol) of ethylene glycol diglycidyl ether (Denacole EX-810, manufactured by Nagase Chemical Industries, Ltd.) “Ethylene glycol diglycidyl ether (manufactured by Nagase Chemical Industries, Ltd.), a ratio of 70:30) and 1.4 parts of a hydrophobic substance (C2-1) carboxy-modified polysiloxane (manufactured by Shin-Etsu Chemical Co., Ltd.)” 10% water / methanol mixed solution of Denacol EX-810) (the mixing ratio of water: methanol is 70:30) 1.8 And a hydrophobic substance (C2-2) amino-modified polysiloxane (manufactured by Shin-Etsu Chemical Co., Ltd.) in the same manner as in Example 1 except that “0.05 part” is used as the absorbent resin particles (23) of the comparative example. Obtained. 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.

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

<Absorption speed under no load measured by DW test>
It measured by the above-mentioned method using each absorptive resin particle 0.50g and the physiological saline which were obtained in Examples 1-18 and Comparative Examples 1-5. The DW test is to determine the wicking capacity of the absorbent resin under no load on a measurement table connected to the burette and the conduit.

<Gel bed permeability test at swelling pressure at 0 psi>
It measured by the above-mentioned method using the absorptive resin particle obtained in Examples 1-18 and Comparative Examples 1-5. The higher the value, the better the absorption speed of the absorber and the liquid permeability between the swollen gels.

Centrifuge retention volume of saline solution
It measured by the above-mentioned method using 0.200 g of absorptive resin particles obtained by Examples 1-18 and comparative examples 1-5. The higher the value, the higher the water absorption performance of the absorbent resin.

<Absorption rate measured by Vortex test>
It measured by the above-mentioned method using each absorptive resin particle obtained in Examples 1-18 and Comparative Examples 1-5.

  From Table 1, when applied to an absorbent article (such as a disposable diaper), the absorbent resin particles in the present invention effectively utilized the entire diaper without causing a bias in urine in the absorbent used in the absorbent article. With a hydrophobic substance having the absorption rate pattern (T2 / T1) necessary for achieving absorption, and a hydrophobic substance having a polysiloxane structure on the surface, it exhibits high GBP and has a high SAP ratio as in thin diapers It can be expected to have excellent urine diffusivity also in the body. On the other hand, the absorbent resin of the comparative example is incompatible with the absorption rate pattern required for absorption of urine in the absorber and GBP. For example, in Comparative Example 1, both the inside and the surface do not contain a hydrophobic substance, and do 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. In addition, according to Comparative Examples 2 and 4, since they have an appropriate absorption rate pattern because they contain appropriate hydrophobic substances on the inside and on the surface, the diffusion of urine is inhibited in the thin diaper absorber because the GBP is low. It is thought to cause urine leakage. Although Comparative Examples 3 and 5 do not have a hydrophobic substance inside, the initial absorption rate is slow and the late absorption rate is slow because they contain a hydrophobic substance having a polysiloxane structure on the surface. Although this promotes early urine diffusion in the absorber, it is thought that subsequent slow urine absorption makes efficient urine absorption difficult and causes urine leakage. From the above, two or more hydrophobic substances of the hydrophobic substance C1 necessary for realizing the optimum absorption rate pattern and the hydrophobic substance C2 necessary for realizing the high GBP are properly distributed on the SAP surface and inside Is found to be good for diaper performance.

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

Preparation 1 of Absorbent Article (Paper Diaper)
80 parts of fluff pulp and 120 parts of evaluation sample {absorbent resin particles} are mixed by an air flow mixer {Pad Former made by Autech Co., Ltd.} to obtain a mixture, and this mixture is weighed about 500 g / w. laminated on m ² and so as to uniformly acrylic plate (thickness 4 mm), and pressed for 30 seconds at a pressure of 5 kg / cm ^2, to obtain absorbent body (1). This absorbent body (1) is cut into a rectangle of 10 cm × 40 cm, and water absorbent paper (15.5 g / m ² basis weight, made by Advantech, filter paper No. 2) of the same size as the absorbent body is arranged above and below each Furthermore, a disposable diaper (1) was prepared by disposing a non-woven fabric (basis weight 20 g / m ² , Eltus Guard manufactured by Asahi Kasei Corp.) on the back surface of a polyethylene sheet (polyethylene film UB-1 manufactured by Tamapoly Corporation). The weight ratio of absorbent resin particles to fibers (weight of absorbent resin particles / weight of fibers) was 60/40.

Preparation 2 of Absorbent Article (Paper Diaper)
Preparation of absorbent article (paper diaper) 1 except that “80 parts of fluff pulp and 120 parts of evaluation sample {absorbent resin particles}” were changed to 60 parts of fluff pulp and 140 parts of evaluation sample {absorbent resin particles} The paper diaper (2) was adjusted similarly to. The weight ratio of absorbent resin particles to fibers (weight of absorbent resin particles / weight of fibers) was 70/30.

<Surface dryness value by SDME method>
A paper diaper fully damped with the detector of the SDME (Surface Dryness Measurement Equipment) tester (manufactured by WK system) {Artificial urine (0.03% by weight of potassium chloride, 0.08% by weight of magnesium sulfate, 0.8% by weight of sodium chloride) % And deionized water 99.09% by weight) were prepared by immersing the disposable diaper for 60 minutes. }, Set the 0% dryness value, and then prepare the detector of the SDME tester by drying the dried disposable diaper {the disposable diaper at 80 ° C. for 2 hours. } And set 100% dryness, and calibrated the SDME tester. Next, set a metal ring (inner diameter 70 mm, length 50 mm) in the center of the paper diaper to be measured, inject 80 ml of artificial urine, and immediately absorb the artificial urine {until the gloss due to artificial urine can not be confirmed}, Remove the metal ring and place three SDME detectors on the center of the paper diaper and its left and right sides (three locations 10 cm apart from the edge of the paper diaper 40 cm) and start measuring the surface dryness value, and 5 minutes after the start of the measurement The values of were taken as SD1-1 {center}, SD1-2 {left} and SD1-3 {right}, respectively.
In addition, artificial urine, measurement atmosphere, and leaving atmosphere were performed at 25 ± 5 ° C. and 65 ± 10% RH.

  The absorbent resin particles of Examples from Table 2 exhibited excellent dryability even in a disposable diaper having a high ratio of absorbent resin particles. In Comparative Example 1, since it does not contain a hydrophobic substance inside, it does not have an appropriate absorption rate pattern, and the dry property is inferior to that of the example. Moreover, in Comparative Examples 2 and 4, in the disposable diaper 1 in which the ratio of the absorbent resin particles is low due to the presence of the hydrophobic substance inside the absorbent resin particles, the appropriate drying property is maintained, but the disposable diaper has a high ratio of absorbent resin particles. In the case of 2, the dry property is reduced. This is considered to be due to the low GBP compared to the example. Since Comparative Examples 3 and 5 do not have an appropriate absorption rate pattern, the dry property is low even in a disposable diaper 1 having a low ratio of absorbent resin particles. From the above, it can be seen that having an early late, mid-normal, late late absorption rate pattern and having a high GBP is effective for the dry performance of a disposable diaper.

The absorbent resin composition of the present invention is characterized in that the liquid permeability between swollen gels and the absorption performance under load can be compatible, and blocking and discoloration during storage are less likely to occur. Since the above effects are exhibited, the absorbent resin composition of the present invention can be used for an absorbent article having a large amount of absorption and excellent reversion and surface dry feeling by being applied to various absorbents. It is suitably used for articles.

Claims (12)

  It contains a water-soluble vinyl monomer (a1) and / or a crosslinked polymer (A) of a monomer composition containing a vinyl monomer (a2) which becomes a water-soluble vinyl monomer (a1) by hydrolysis and an internal crosslinking agent (b) Absorbent resin particles, and in the Demand Wettability test method, a time (t1) until absorption amount to physiological saline per 1 g of absorbent resin particles reaches 2 g and a time until absorption amount reaches 20 g (t2) Absorbent resin particles whose ratio (t2 / t1) is 2 to 20 and whose gel bed permeability at 0 psi swelling pressure is 40 darcies or more.   The absorbent resin particle according to claim 1, wherein the time (t1) for the absorption amount to reach 2 g in the Demand Wettability test method is 5 seconds to 60 seconds.   At least one selected from the group of fatty acid esters having 8 to 30 carbon atoms, fatty acids having 8 to 30 carbon atoms and salts thereof, aliphatic alcohols having 8 to 30 carbon atoms, and aliphatic group-containing amides having 8 to 30 carbon atoms The absorbent resin particles according to claim 1 or 2, comprising a certain hydrophobic substance (C1) and a hydrophobic substance (C2) which is an organic polysiloxane.   The hydrophobic substance (C1) is at least one selected from the group consisting of sorbite stearic acid ester, sucrose stearic acid ester, stearic acid, magnesium stearate, calcium stearate, zinc stearate and aluminum stearate. Absorbent resin particles.   The absorbent resin particles according to claim 3 or 4, wherein the hydrophobic substance (C1) is sucrose stearate or Mg stearate.   The hydrophobic substance (C2) is at least one selected from the group consisting 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.   The content of the hydrophobic substance (C1) present 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 particle according to any one of the preceding claims.   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 absorptive resin particle of any one of Claims 3-7.   9. The absorbency according to any one of claims 1 to 8, wherein the centrifuge retention amount by the CRC test method of physiological saline is 25 to 36 g / g, and the absorption rate measured by the Vortex test method is 40 seconds or less. Resin particles.   The absorber formed by containing the absorptive resin particle of any one of Claims 1-9.   The absorbent according to claim 10, further comprising a fibrous material.   An absorbent article comprising the absorber according to claim 10 or 11.