JP7120739B2 - Absorbent resin composition particles and method for producing the same - Google Patents

Description

TECHNICAL FIELD The present invention relates to absorbent resin composition particles and a method for producing the same.

A partially neutralized crosslinked product of polyacrylic acid is known as a body fluid-absorbing resin used in sanitary materials, and is widely used in paper diapers, sanitary napkins, and the like. It is known that when the object to be absorbed is blood, unlike urine, it contains a large amount of solid components such as blood cells, so the amount of liquid is small, and menstrual blood is known to contain even less liquid. Conventionally, in order to absorb blood, water-insoluble inorganic substances, water-insoluble hydrophilic fibrous substances, etc. are attached to the surface of the absorbent resin, and the absorbent composite has excellent absorption performance for highly viscous blood. is known (see Patent Documents 1 and 2). In recent years, by adding polyols and cationic metal salts during surface cross-linking in the process of manufacturing absorbent resins, powdery cross-linked absorbents capable of absorbing aqueous liquids and blood, which can exhibit high absorption capacity under pressure, have been developed. are known, as well as their method of preparation (see US Pat. However, even in these methods, there is a problem in the dryness of the absorbent material, because the absorption performance is not necessarily exhibited sufficiently for bodily fluids such as blood that contain little liquid.

Japanese Patent Publication No. 7-28891 Japanese Patent Publication No. 7-20549 JP 2012-97276 A

An object of the present invention is to provide absorbent resin composition particles that are excellent in the effect of absorbing aqueous liquids, particularly blood.

The present invention comprises a water-soluble vinyl monomer (a1) and/or a vinyl monomer (a2) that becomes a water-soluble vinyl monomer (a1) by hydrolysis as an essential structural unit, a surface-crosslinked polymer (A), and a solubility A parameter of 8.5 to 17.0 (cal/cm ³ ) ^1/2 , a viscosity of 20 to 7000 mPa·s at 25°C , and 2 to 3 hydroxyl groups in one molecule. an absorbent resin composition particle containing a polyvalent hydroxyl group-containing compound (B), having the polyvalent hydroxyl group-containing compound (B) on the surface of the absorbent resin composition particle, and the polyvalent hydroxyl group Contains 3.0 to 15 % by weight of the compound (B) based on the weight of the polymer (A), and the polyhydroxyl group-containing compound (B) is polyoxyethylene sorbitan monolaurate and/or sorbitan Absorbent resin composition particles that are monolaurate and an absorber suitable for blood absorption using the same; The present invention relates to a method for producing absorbent resin composition particles including a step of mixing a hydroxyl group-containing compound (B).

The absorbent resin composition particles of the present invention and the absorbent resin composition particles obtained by the production method of the present invention are excellent in the dryness of the absorbent against body fluids, particularly blood. Therefore, it exhibits stable and excellent absorption performance with respect to body fluids such as blood under various conditions of use.

The absorbent resin composition particles of the present invention are composed of a water-soluble vinyl monomer (a1) and/or a polymer (A) having a vinyl monomer (a2) which becomes a water-soluble vinyl monomer (a1) by hydrolysis as an essential constituent unit. , and a polyvalent hydroxyl group-containing compound (B) having an SP value ((cal/cm ³ ) ^1/2 ) of 7.0 to 19.0 and a viscosity at 25° C. of 20 to 8000 mPa·s These are absorbent resin composition particles.

The water-soluble vinyl monomer (a1) in the present invention is not particularly limited. vinyl monomers having saturated groups (e.g., anionic vinyl monomers, nonionic vinyl monomers and cationic vinyl monomers), anionic vinyl monomers disclosed in paragraphs 0009 to 0024 of JP-A-2003-165883, nonionic carboxyl 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 and cationic vinyl monomers. Any vinyl monomer having at least one of the following can be used.

A vinyl monomer (a2) that becomes a water-soluble vinyl monomer (a1) by hydrolysis [hereinafter also referred to as a hydrolyzable vinyl monomer (a2). ] is not particularly limited, and is known {for example, a vinyl monomer having at least one hydrolyzable substituent that becomes a water-soluble substituent by hydrolysis disclosed in paragraphs 0024 to 0025 of Japanese Patent No. 3648553; At least one hydrolyzable substituent [1,3-oxo-2-oxapropylene (-CO-O-CO-) group, acyl group and cyano A vinyl monomer having a group, etc.} can be used. The term "water-soluble vinyl monomer" is a concept well known to those skilled in the art, but if expressed in terms of quantity, it means, for example, a vinyl monomer that dissolves in 100 g of water at 25° C. in an amount of at least 100 g. Further, the hydrolyzability of the hydrolyzable vinyl monomer (a2) means, for example, the property of being hydrolyzed by the action of water and, if necessary, a catalyst (acid, base, etc.) to become water-soluble. Hydrolysis of the hydrolyzable vinyl monomer (a2) may be carried out during polymerization, after polymerization, or both. Later is preferred.

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

In addition, "carboxy (salt) group" means "carboxy group" or "carboxylate group", and "sulfo (salt) group" means "sulfo group" or "sulfonate group". (Meth)acrylic acid (salt) means acrylic acid, acrylate, methacrylic acid or methacrylate, and (meth)acrylamide means acrylamide or methacrylamide. Examples of salts include alkali metal (lithium, sodium, potassium, etc.) salts, alkaline earth metal (magnesium, calcium, etc.) salts, ammonium (NH ₄ ) salts, and the like. Among these salts, alkali metal salts and ammonium salts are preferable, alkali metal salts are more preferable, and sodium salts are particularly preferable, from the viewpoint of absorption performance and the like.

When either the water-soluble vinyl monomer (a1) or the hydrolyzable vinyl monomer (a2) is used as a structural unit, each one type may be used alone as a structural unit, and if necessary, two or more types may be used as a structural unit. good. The same applies to the case where the water-soluble vinyl monomer (a1) and the hydrolyzable vinyl monomer (a2) are used as structural units. Further, when the water-soluble vinyl monomer (a1) and the hydrolyzable vinyl monomer (a2) are used as structural units, the molar ratio [(a1)/(a2)] of these contents is preferably 75/25 to 99/1. , more preferably 85/15 to 95/5, particularly preferably 90/10 to 93/7. Within this range, the absorption performance is further improved.

As structural units of the polymer (A), 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 structural units. can. Other vinyl monomers (a3) may be used alone or in combination of two or more.

Other vinyl monomers (a3) are not particularly limited, and are known (for example, hydrophobic vinyl monomers disclosed in paragraphs 0028 to 0029 of Japanese Patent No. 3648553; Hydrophobic vinyl monomers such as the vinyl monomers disclosed in paragraph 0058 of JP-A-2005-75982) can be used, and specifically, the following vinyl monomers (i) to (iii) can be used.
(i) Aromatic ethylenic monomer having 8 to 30 carbon atoms Styrene such as styrene, α-methylstyrene, vinyltoluene and hydroxystyrene, and halogen-substituted styrene such as vinylnaphthalene and dichlorostyrene.
(ii) Aliphatic ethylenic monomers having 2 to 20 carbon atoms Alkenes (ethylene, propylene, butene, isobutylene, pentene, heptene, diisobutylene, octene, dodecene, octadecene, etc.); and alkadienes (butadiene, isoprene, etc.).
(iii) C5-C15 alicyclic ethylenic monomers monoethylenically unsaturated monomers (pinene, limonene, indene, etc.); and polyethylene vinyl monomers [cyclopentadiene, bicyclopentadiene, ethylidenenorbornene, etc.], and the like.

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

The polymer (A) may be crosslinked with an internal crosslinker, if necessary. The internal cross-linking agent is not particularly limited and is known (for example, cross-linking agents having two or more ethylenically unsaturated groups disclosed in paragraphs 0031 to 0034 of Japanese Patent No. 3648553, functional groups capable of reacting with water-soluble substituents, a cross-linking agent having at least one group and at least one ethylenically unsaturated group and a cross-linking agent having at least two functional groups capable of reacting with a water-soluble substituent, JP-A-2003-165883, 0028 A cross-linking agent having two or more ethylenically unsaturated groups, a cross-linking agent having an ethylenically unsaturated group and a reactive functional group, and a cross-linking agent having two or more reactive substituents disclosed in paragraphs 1 to 0031, particularly Cross-linkable vinyl monomers disclosed in paragraph 0059 of JP-A-2005-75982 and cross-linkable vinyl monomers disclosed in paragraphs 0015-0016 of JP-A-2005-95759 can be used. Among these, from the viewpoint of absorption performance and the like, cross-linking agents having two or more ethylenically unsaturated groups are preferable, and more preferable are triallyl cyanurate, triallyl isocyanurate and polyols having 2 to 40 carbon atoms ( Meta)allyl ethers, particularly preferred are triallyl cyanurate, triallyl isocyanurate, tetraallyloxyethane, polyethylene glycol diallyl ether and pentaerythritol triallyl ether, most preferred is pentaerythritol triallyl ether. The internal cross-linking agent may be used singly or in combination of two or more.

Polymer (A) can be polymerized by aqueous solution polymerization (adiabatic polymerization, thin film polymerization, spray polymerization, etc.; JP-A-55-133413, etc.), known suspension polymerization methods and reverse-phase suspension polymerization ( JP-B-54-30710, JP-A-56-26909, JP-A-1-5808, etc.).

When aqueous polymerization is carried out, a mixed solvent containing water and an organic solvent can be used, and examples of the organic solvent include methanol, ethanol, n-propyl alcohol, isopropyl alcohol, n-butanol, isobutyl alcohol and t-butyl alcohol. , isopentyl alcohol, acetone, methyl ethyl ketone, N,N-dimethylformamide, dimethylsulfoxide and mixtures of two or more thereof.
The amount (% by weight) of the organic solvent used is preferably 40 or less, more preferably 30 or less, based on the weight of water.

When the suspension polymerization method or the reversed-phase suspension polymerization method is employed, the polymerization may be carried out in the presence of a conventionally known dispersant or surfactant. Moreover, in the case of the reversed-phase suspension polymerization method, the polymerization can be carried out using a hydrocarbon solvent such as xylene, normal hexane and normal heptane.

When an initiator is used for polymerization, radical polymerization initiators can be used, for example, azo compounds [azobisisobutyronitrile, azobiscyanovaleric acid and 2,2'-azobis(2-amidinopropane) hydrochloride, etc. ], inorganic peroxides (hydrogen peroxide, ammonium persulfate, potassium persulfate and sodium persulfate, etc.), organic peroxides [benzoyl peroxide, di-t-butyl peroxide, cumene hydroperoxide, succinic acid peroxide and di(2-ethoxyethyl) peroxydicarbonate, etc.] and redox catalysts (alkaline metal sulfites or bisulfites, ammonium sulfite, ammonium bisulfite, and reducing agents such as ascorbic acid and alkali metal persulfates, persulfates, A combination with an oxidizing agent such as ammonium sulfate, hydrogen peroxide and organic peroxide). These catalysts may be used alone, or two or more of them may be used in combination.
The amount (% by weight) of the radical polymerization initiator used is the water-soluble vinyl monomer (a1) and the hydrolyzable vinyl monomer (a2), and when the other vinyl monomer (a3) is used, (a1) to (a3). , preferably 0.0005 to 5, more preferably 0.001 to 2, based on the total weight.

At the time of polymerization, a polymerization control agent represented by a chain transfer agent may be used in combination as necessary. Specific examples thereof include sodium hypophosphite, sodium phosphite, alkyl mercaptans, alkyl halides. , thiocarbonyl compounds and the like. These polymerization control agents may be used alone, or two or more of them may be used in combination.
The amount (% by weight) of the polymerization control agent used is the water-soluble vinyl monomer (a1) and the hydrolyzable vinyl monomer (a2). Preferably 0.0005 to 5, more preferably 0.001 to 2, based on total weight.

The polymerization initiation temperature can be appropriately adjusted depending on the type of catalyst used, but is preferably 0 to 100°C, more preferably 2 to 80°C.

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

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

The polymer (A) can be obtained by polymerizing a monomer composition containing the water-soluble vinyl monomer (a1) and/or the hydrolyzable vinyl monomer (a2) as essential constituents. Preferred is an aqueous solution polymerization method which does not require the use of an organic solvent or the like and is advantageous in terms of production cost. Most preferred is an aqueous solution adiabatic polymerization method that does not require temperature control during polymerization.

A water-containing gel-like material (hereinafter abbreviated as a water-containing gel) can be obtained by the polymerization method described above, and if necessary, the polymer (A) is obtained by surface-crosslinking the particulate polymer obtained by drying the water-containing gel. You can also get When using an acid group-containing monomer such as acrylic acid or methacrylic acid as the water-soluble vinyl monomer (a1), the water-containing gel may be neutralized with a base. The degree of neutralization of acid groups is preferably 50 to 80 mol %. If the degree of neutralization is less than 50 mol %, the resulting hydrous gel polymer will have high adhesiveness, and workability during production and use may deteriorate. Furthermore, the water retention capacity of the resulting aqueous liquid absorbent resin may decrease. On the other hand, when the degree of neutralization exceeds 80%, the resulting resin has a high pH, which may pose a concern about the safety of the human skin.
The neutralization may be performed at any stage after the polymerization of the monomer composition in the production of the absorbent resin composition particles. be done.
As the neutralizing base, alkali metal hydroxides such as sodium hydroxide and potassium hydroxide, and alkali metal carbonates such as sodium carbonate, sodium hydrogencarbonate and potassium carbonate can be used.

The hydrous gel obtained by polymerization can be chopped before drying, if desired. The size (maximum diameter) of the gel after shredding is preferably 50 μm to 10 cm, more preferably 100 μm to 2 cm, particularly preferably 1 mm to 1 cm. Within this range, the drying property in the drying step is further improved.

Shredding can be performed by a known method, and can be shredded using an ordinary shredding device (e.g., Vex mill, rubber chopper, farmer mill, mincing machine, impact pulverizer, and roll pulverizer). .

The content and water content of the organic solvent were measured using an infrared moisture meter [JE400 manufactured by KETT Co., Ltd., etc.: 120 ± 5 ° C., 30 minutes, atmospheric humidity before heating 50 ± 10% RH, lamp specification 100 V, 40 W].

As a method for distilling off the solvent (including water) of the hydrous gel and drying it, a method of distilling (drying) with hot air at a temperature of 80 to 230 ° C., a drum dryer heated to 100 to 230 ° C., etc. A thin film drying method, a (heating) vacuum drying method, a freeze drying method, an infrared drying method, decantation, filtration, and the like can be applied. Although the drying time is not particularly limited, it is preferably 0 to 3 hours, more preferably 0 to 30 minutes, from the viewpoint of deterioration of the gel due to overdrying.

The shape and particle size of the polymer (A) can be controlled by pulverization and classification, if necessary. Examples of the shape of the polymer (A) include irregular pulverized shape, scaly shape, pearl shape, rice grain shape, and the like. Of these, irregularly crushed forms are preferred from the viewpoints of good entanglement with fibrous materials for use in paper diapers and the like, and no fear of falling off from fibrous materials.
The method of pulverization is not particularly limited, and conventional pulverizers (eg, hammer type pulverizer, impact type pulverizer, roll type pulverizer and jet jet type pulverizer) and the like can be used. The pulverized polymer can be adjusted in particle size by sieving or the like, if necessary.

The weight average particle size (μm) of the polymer (A) is preferably 100-500, more preferably 150-480, and particularly preferably 200-450. Within this range, the absorption performance of the absorbent resin composition particles is further improved.
From the viewpoint of absorption performance, the content (% by weight) of fine particles of 106 μm or less (preferably 150 μm or less) in the total weight of the polymer (A) is preferably 3 or less, more preferably 1 or less. The content of fine particles can be determined using the graph created when determining the weight-average particle size.

The weight average particle size is measured using a low-tap test sieve shaker and standard sieve (JIS Z8801-1: 2006), Perry's Chemical Engineers Handbook 6th Edition (McGraw Hill Book Company, 1984, 21 page). That is, JIS standard sieves of 1000 μm, 850 μm, 710 μm, 500 μm, 425 μm, 355 μm, 250 μm, 150 μm, 125 μm, 75 μm and 45 μm and a saucer are combined in this order from the top. About 50 g of the particles to be measured are placed in the top sieve and shaken for 5 minutes with a Rotap test sieve shaker. The weight of the particles to be measured on each sieve and the tray is weighed, the total is 100% by weight, and the weight fraction of the particles on each sieve is obtained. ) and the weight fraction on the vertical axis], draw a line connecting the points, determine the particle diameter corresponding to a weight fraction of 50% by weight, and take this as the weight average particle diameter.

The polymer (A) may contain some amount of other components such as residual solvent and residual cross-linking component within the range not impairing its performance.

The polymer (A) of the present invention can have a structure in which its surface is crosslinked with a surface cross-linking agent (d). By cross-linking the surface of the polymer (A), the gel strength of the absorbent resin composition particles can be improved, and the desired water retention capacity and absorption capacity under load of the absorbent resin composition particles can be satisfied. It is preferable because it can be done. As the surface cross-linking agent (d), known (polyvalent glycidyl compounds, polyvalent amines, polyvalent aziridine compounds and polyvalent isocyanate compounds described in JP-A-59-189103, etc., JP-A-58-180233 And the polyhydric alcohol of JP-A-61-16903, the silane coupling agent described in JP-A-61-211305 and JP-A-61-252212, the JP-A-5-508425 described Alkylene carbonates, polyvalent oxazoline compounds described in JP-A-11-240959, and surface-crosslinking agents such as polyvalent metals described in JP-A-51-136588 and JP-A-61-257235 can be used. Among these surface cross-linking agents, polyhydric glycidyl compounds, polyhydric alcohols and polyhydric amines are preferred from the viewpoint of economy and absorption properties, more preferred are polyhydric glycidyl compounds and polyhydric alcohols, and particularly preferred is A polyhydric glycidyl compound, most preferably ethylene glycol diglycidyl ether, may be used alone or in combination of two or more surface cross-linking agents.

The amount (parts by weight) of the surface cross-linking agent (d) used is not particularly limited because it can be varied depending on the type of the surface cross-linking agent, cross-linking conditions, target performance, etc., but from the viewpoint of absorption characteristics and the like. , preferably 0.001 to 3, more preferably 0.005 to 2, particularly preferably 0.01 to 1.5, relative to 100 parts by weight of the absorbent resin.

Surface cross-linking of the polymer (A) can be carried out by mixing the polymer (A) and the surface cross-linking agent (d) and, if necessary, heating. The method for mixing the polymer (A) and the surface cross-linking agent (d) includes a cylindrical mixer, a screw mixer, a screw extruder, a turbulizer, a Nauta mixer, a twin-arm kneader, and a fluid type. Polymer (A) using a mixing device such as a mixer, a V-type mixer, a mincing mixer, a ribbon mixer, a fluidized mixer, an airflow mixer, a rotating disk mixer, a conical blender and a roll mixer. and the surface cross-linking agent (d) are uniformly mixed. At this time, the surface cross-linking agent (d) may be diluted with water and/or any solvent before use.

The temperature at which the polymer (A) and the surface cross-linking agent (d) are mixed is not particularly limited, but is preferably 10 to 150°C, more preferably 20 to 100°C, and particularly preferably 25 to 80°C.

After mixing the polymer (A) and the surface cross-linking agent (d), a heat treatment is usually performed to obtain the surface-crosslinked polymer (A). The heating temperature is preferably 100 to 180°C, more preferably 110 to 175°C, particularly preferably 120 to 170°C, from the viewpoint of breaking resistance of the resin particles. Heating at 180° C. or less enables indirect heating using steam, which is advantageous in terms of facilities. Heating temperatures below 100° C. may result in poor absorption performance. The heating time can be appropriately set depending on the heating temperature, but from the viewpoint of absorption performance, it is preferably 5 to 60 minutes, more preferably 10 to 40 minutes. The surface-crosslinked polymer (A) can be further surface-crosslinked using a surface-crosslinking agent that is the same as or different from the surface-crosslinking agent used first.

The polymer (A) obtained by surface cross-linking is sieved if necessary to adjust the particle size. The weight average particle size of the obtained particles is preferably 100-500 μm, more preferably 200-450 μm. The content of fine particles is preferably as small as possible, the content of particles of 100 μm or less is preferably 3% by weight or less, and the content of particles of 150 μm or less is more preferably 3% by weight or less.

In the absorbent resin composition particles of the present invention, the polymer (A) may be further treated with a hydrophobic substance, and as a method for treating with a hydrophobic substance, the method described in JP-A-2013-231199 and the like can be used. Available.

The absorbent resin composition particles of the present invention have a solubility parameter [SP value: (cal/cm ³ ) ^1/2 ] of 7.0 to 19.0 and a viscosity at 25° C. of 20 to 8000 mPa·s. It contains a polyvalent hydroxyl group-containing compound (B).

The polyvalent hydroxyl group-containing compound (B) is a compound having a plurality of hydroxyl groups in one molecule, and having a plurality of hydroxyl groups provides the effect of blood absorption. It preferably has 2 to 8 hydroxyl groups, more preferably 2 to 6 hydroxyl groups, and particularly preferably 2 to 3 hydroxyl groups. The polyvalent hydroxyl group-containing compound (B) may be used singly or in combination of two or more.

The SP value [(cal/cm ³ ) ^1/2 ] of (B) is preferably 7.5 to 18.0, more preferably 8.5 to 17.0, from the viewpoint of blood absorption and absorption rate. .
The solubility parameter (SP) value is obtained by the following formula.
SP = (ΔH/V) ^1/2

However, in the formula, ΔH represents molar heat of vaporization (cal/mol) and V represents molar volume (cm ³ /mol). In addition, ΔH and V are the molar heats of vaporization (Δei) of atomic groups described in "POLYMER ENGINEERING AND SCIENCE, February, 1974, Vol. 14, No. 2, Robert F. Fedors. (pp. 147-154)" (ΔH) and the sum (V) of the molar volumes (Δvi) can be used.

The viscosity of the polyvalent hydroxyl group-containing compound (B) at 25° C. is from 20 to 8000 mPa·s, preferably from 20 to 7000 mPa·s, from the viewpoint of blood absorption and absorption rate.

The polyvalent hydroxyl group-containing compound (B) is a compound having a polyvalent hydroxyl group adjusted so that the SP value is 7.0 to 19.0 and the viscosity at 25 ° C. is 20 to 8000 mPa s. From the viewpoint of properties, it is preferably selected from polyhydric alcohols, polyhydric alcohol fatty acid esters, polysaccharides, polysaccharide fatty acid esters, and the like. More preferred are polyhydric alcohols, polysaccharide fatty acid esters and polyhydric alcohol fatty acid esters. Specifically, particularly preferred are, for example, sorbitan monolaurate (SP value (unit omitted) 12.8, viscosity 5000 mPa s), sorbitan monooleate (SP value (unit omitted) 11.9, viscosity 1000 mPa s). s), polyoxyethylene sorbitan monolaurate (SP value (unit omitted) 10.4, viscosity 400 mPa s), polyoxyethylene sorbitan monooleate (SP value (unit omitted) 18.8, viscosity 425 mPa s) , polyoxyethylene sorbitan monostearate (SP value (unit omitted) 10.3, viscosity 500 mPa s), ethylene glycol (SP value (unit omitted) 17.8, viscosity 21 mPa s), diethylene glycol (SP value (unit omitted) 15.0, viscosity 36 mPa s), triethylene glycol (SP value (units omitted) 13.6, viscosity 48 mPa s), propylene glycol (SP value (units omitted) 15.9, viscosity 48 mPa s) , 1,2-butanediol (SP value (unit omitted) 14.8, viscosity 40 mPa s), 1,3-butanediol (SP value (unit omitted) 14.8, viscosity 45 mPa s), 1,4 -butanediol (SP value (unit omitted) 15.0, viscosity: 65 mPa·s) and 1,2-pentanediol (SP value (unit omitted) 14.0, viscosity: 60 mPa·s). Most preferably, polyoxyethylene sorbitan monolaurate (SP value (unit omitted) 10.4, viscosity 400 mPa s), sorbitan monolaurate (SP value (unit omitted) 12.8, viscosity 5000 mPa s), propylene Glycol (SP value (unit omitted) 15.9, viscosity 48 mPa·s).

The absorbent resin composition particles of the present invention preferably have the polyvalent hydroxyl group-containing compound (B) on the surface of the resin particles. The presence of the polyhydroxyl group-containing compound (B) on the surface of the resin particles can improve the affinity with blood, and as a result, it is possible to further improve the absorption characteristics with respect to blood. Therefore, it is preferable to add the polyvalent hydroxyl group-containing compound (B) after the surface cross-linking step. The weight of the polyvalent hydroxyl group-containing compound (B) based on the weight of the polymer (A) is 1.0 to 20% by weight, preferably 3.0 to 15% by weight, more preferably 4.0 to 13%. % by weight.

The absorbent resin composition particles of the present invention can be obtained by mixing the polymer (A) and the polyvalent hydroxyl group-containing compound (B). Mixing methods include a cylindrical mixer, a screw mixer, a screw extruder, a turbulizer, a Nauta mixer, a twin-arm kneader, a fluid mixer, a V mixer, a mince mixer, and a ribbon mixer. A method of uniform mixing using a known mixing apparatus such as a mixer, a fluidized mixer, an airflow mixer, a rotating disc mixer, a conical blender, and a roll mixer can be used.

Mixing of the polymer (A) and the polyvalent hydroxyl group-containing compound (B) is preferably carried out by adding the polyvalent hydroxyl group-containing compound (B) while stirring the polymer (A). The polyvalent hydroxyl group-containing compound (B) to be added may be added simultaneously with water and/or the solvent. When the polyvalent hydroxyl group-containing compound (B) is added simultaneously with water and / or a solvent, a solution of the polyvalent hydroxyl group-containing compound (B) dissolved in water and / or a solvent or a solution of the polyvalent hydroxyl group-containing compound (B) in water and / or a solvent / Alternatively, a dispersion dispersed in a solvent can be added, and from the viewpoint of workability, it is preferable to add a solution, and it is more preferable to add a solution dissolved in water. When adding a solution or dispersion, it is preferably added by spraying or dropwise.

When using an aqueous solution obtained by dissolving the polyvalent hydroxyl group-containing compound (B) in water, the content of the polyvalent hydroxyl group-containing compound (B) contained in the aqueous solution is 5 to 5 with respect to the total weight of the aqueous solution from the viewpoint of blood absorption rate. 70% by weight is preferred, more preferably 10-60% by weight. When the concentration is lower than the above range, the polyvalent hydroxyl group-containing compound (B) permeates into the interior of the polymer, resulting in a decrease in the blood absorption rate.

The type of solvent is not particularly limited, but monohydric alcohols (ethanol, isopropanol, etc.) and polyhydric alcohols (glycerin, polyoxyethylene glycol, etc.) are preferably used. More than one species may be used in combination.

The temperature at which the polymer (A) and the polyvalent hydroxyl group-containing compound (B) are mixed is preferably 20 to 140°C, more preferably 40 to 120°C.

When the polymer (A) and the polyhydroxyl group-containing compound (B) are mixed and then heated, the heating time can be appropriately set depending on the heating temperature. It is preferably 10 to 40 minutes.

The absorbent resin composition particles of the present invention may be used after mixing the polymer (A) and the polyvalent hydroxyl group-containing compound (B) and then sieving to adjust the particle size. The weight-average particle diameter of particles obtained by adjusting the particle size is preferably 100 to 600 μm, more preferably 150 to 500 μm.

The absorbent resin composition particles of the present invention may further contain water-insoluble inorganic particles (f). By including the water-insoluble inorganic particles (f), the surfaces of the particles contained in the absorbent resin composition particles are surface-treated with the water-insoluble inorganic particles (f), thereby improving the blocking resistance and Improves liquid permeability.

Examples of the water-insoluble inorganic particles (f) include colloidal silica, fumed silica, clay and talc. Colloidal silica and silica are preferred and more preferred from the viewpoint of availability, ease of handling and absorption performance. is colloidal silica. The water-insoluble inorganic particles (f) may be used singly or in combination of two or more.

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

When the water-insoluble inorganic particles (f) are included, it is preferable to mix the absorbent resin composition particles and the water-insoluble inorganic particles (f), and the mixing is the same as the mixing of the polyvalent hydroxyl group-containing compound (B). and the conditions are the same.

The absorbent resin composition particles after mixing the water-insoluble inorganic particles (f) may be used after adjusting the particle size, and the particle size adjustment is the same as the particle size adjustment after mixing the polyvalent hydroxyl group-containing compound (B). The same applies to the particle size after particle size adjustment.

The absorbent resin composition particles of the present invention may optionally contain additives (for example, known antiseptic agents (described in JP-A-2003-225565 and JP-A-2006-131767), antifungal agents, and antibacterial agents. , antioxidants, ultraviolet absorbers, colorants, fragrances, deodorants, liquid permeability improvers, organic fibrous substances, etc.). When these additives are contained, the content (% by weight) of the additives is preferably 0.001 to 10, more preferably 0.01 to 5, particularly preferably 0.01 to 5, based on the weight of the polymer (A). is between 0.05 and 1, most preferably between 0.1 and 0.5.

The production method of the present invention has a step of mixing a polymer (A) and a polyvalent hydroxyl group-containing compound (B), preferably a solution thereof. The step of mixing the polymer (A) and the polyvalent hydroxyl group-containing compound (B), preferably a solution thereof, comprises mixing the polymer (A) and the polyvalent hydroxyl group-containing compound (B), preferably a solution thereof, as described above. can be carried out by mixing using a known mixing device. The temperature during mixing is preferably 100 to 140°C, more preferably 100 to 120°C. By forming a solution of the polyvalent hydroxyl group-containing compound (B), the polymer (A) and the polyvalent hydroxyl group-containing compound (B) can be uniformly mixed, and the quality is stabilized. After cross-linking the surface of the polymer (A) with the surface cross-linking agent (d), it is preferable to mix the polyvalent hydroxyl group-containing compound (B). The production method of the present invention is suitable for obtaining the water absorbent resin particles of the present invention.

The water content of the absorbent resin composition particles of the present invention is preferably 1 to 10% by weight, more preferably 2 to 9% by weight, still more preferably 3 to 8% by weight, from the viewpoint of absorption properties.
The apparent density (g/ml) of the absorbent resin composition particles of the present invention is preferably 0.52 to 0.70, more preferably 0.54 to 0.68, particularly preferably 0.56 to 0.66. is. Within this range, the function of fixing the absorbent resin (gel) swollen by urination or the like in the absorbent article is further improved. The apparent density of absorbent resin composition particles is measured at 25° C. in accordance with JIS K7365:1999.

The water retention capacity (g/g) per unit weight of the absorbent resin composition particles of the present invention can be measured by the method described later, and is preferably 20 or more, more preferably 22 or more, from the viewpoint of blood absorption. , 24 or greater are even more preferred. Moreover, the upper limit is preferably 60 or less, more preferably 55 or less, from the viewpoint of absorption under load. The amount of water retention can be appropriately adjusted by the amount (% by weight) of the surface cross-linking agent (d) used.

The blood absorption capacity of the absorbent resin composition particles of the present invention, expressed as the weight of blood absorbed with respect to the weight of the absorbent resin composition particles, can be measured by the method described later. Therefore, it is preferably 2 times or more, more preferably 4 times or more, and even more preferably 10 times or more. In addition, the upper limit is preferably 25 times or less, more preferably 20 times or less, from the viewpoint of absorption under load.

The blood absorption speed of the absorbent resin composition particles in the present invention expressed in time (seconds) from when 1.0 g of blood is added to 0.2 g of absorbent resin composition particles until the blood loses its fluidity is , can be measured by the method described later, and from the viewpoint of the dryness of the absorbent, the time is preferably 120 seconds or less, more preferably 100 seconds or less, and even more preferably 90 seconds or less.

The gel strength of the absorbent resin composition particles of the present invention can be measured by the method described below. The above is even more preferable. From the viewpoint of absorption performance, the upper limit is preferably 4,000 or less, more preferably 3,900 or less, and even more preferably 3,700 or less.

The absorbent resin composition particles of the present invention constitute, for example, absorbent bodies used in sanitary materials such as paper diapers, sanitary napkins, incontinence pads, and medical pads, and are suitable for absorbent articles containing absorbent bodies. It has excellent absorption properties, especially for blood. Examples of blood-absorbing articles include sanitary napkins, tampons, medical sheets, drip absorbents, wound-protecting materials, wound-healing materials, surgical waste liquid treatment agents, and other articles that require blood-absorbing properties.

The absorbent body using the absorbent resin composition particles of the present invention has excellent absorption of body fluids such as blood, has excellent liquid uptake speed, and has excellent dry touch under pressure after absorption. Cracks and deformation can be suppressed.

An absorbent using absorbent resin composition particles is composed of, for example, absorbent resin composition particles and hydrophilic fibers. Specific examples of hydrophilic fibers include wood pulp fibers such as mechanical pulp, chemical pulp, semi-chemical pulp and dissolving pulp derived from wood, and artificial cellulose fibers such as rayon and acetate. Preferred hydrophilic fibers are wood pulp fibers. These hydrophilic fibers may partially contain synthetic fibers such as nylon and polyester.

The content of the absorbent resin composition particles in the absorbent body is preferably 5 to 95% by mass, more preferably 20 to 90% by mass, more preferably 30 to 80% by mass, from the viewpoint of lightness and thinning. % is more preferred.

The structure of the absorbent includes a mixed dispersion obtained by mixing absorbent resin composition particles and hydrophilic fibers so as to have a uniform composition, and an absorbent resin composition between layered hydrophilic fibers. Examples include a sandwich structure in which particles are sandwiched, and a structure in which absorbent resin composition particles and hydrophilic fibers are wrapped in tissue. The absorber may contain other components such as heat-fusible synthetic fibers, hot-melt adhesives, and adhesive binders such as adhesive emulsions for enhancing shape retention of the absorber. .

In addition, an absorbent body using absorbent resin composition particles is held between a liquid permeable sheet (top sheet) through which liquid can pass and a liquid impermeable sheet (back sheet) through which liquid cannot pass. By doing so, an absorbent article can be obtained. The liquid permeable sheet is arranged on the side in contact with the body, and the liquid impermeable sheet is arranged on the opposite side in contact with the body.

Examples of liquid-permeable sheets include air-through type, spunbond type, chemical bond type, needle punch type nonwoven fabrics and porous synthetic resin sheets made of fibers such as polyethylene, polypropylene and polyester. Examples of liquid-impermeable sheets include synthetic resin films made of resins such as polyethylene, polypropylene, and polyvinyl chloride.

EXAMPLES The present invention will be further described below with reference to Examples and Comparative Examples, but the present invention is not limited to these. In addition, unless otherwise specified, parts indicate parts by weight and % indicates weight %. The water retention capacity of the absorbent resin composition particles in physiological saline, blood absorption capacity, blood absorption rate, and weight average molecular weight were measured at 25±2° C. by the following methods.

<Blood absorption ratio>
0.1 g of the sample was added to a nylon mesh bag, and the four sides were heat-sealed. 15 g of horse blood was prepared in advance in a beaker, and a nylon mesh bag containing the sample was immersed in the beaker for 15 minutes. After 15 minutes, the nylon mesh was removed, hung for 1 minute to remove excess blood, and weighed. The blood absorption capacity was obtained by subtracting the weight before absorption and the absorption amount when only the nylon mesh was immersed from the weight after blood absorption and dividing the value by 0.1 g.

<Blood absorption speed>
0.2 g of sample was spread evenly over the entire bottom surface of a 9 ml screw vial, and 1.0 g of horse blood was added all at once. Absorption speed (seconds). In this measurement, the term "no fluidity" means a state in which blood does not flow independently of the sample when the bottom surface of the screw vial is tilted 45 degrees with respect to the horizontal. Therefore, even if there is blood absorbed by the sample on the surface of the sample, if there is no blood that flows independently of the sample, it is determined that the sample has no fluidity.

<Method for measuring water retention>
Put 1.00 g of the measurement sample in a tea bag (20 cm long, 10 cm wide) made of nylon mesh with an opening of 63 μm (JIS Z8801-1: 2006), and put it in 1,000 ml of physiological saline (salt concentration 0.9%). After being immersed for 1 hour without stirring, it was taken out and hung for 15 minutes to drain. After that, the whole tea bag was placed in a centrifuge and dehydrated by centrifugation at 150 G for 90 seconds to remove excess physiological saline. The physiological saline used and the temperature of the measurement atmosphere were 25°C ± 2°C. (h2) is the weight of the tea bag measured in the same manner as above without the measurement sample.
Water retention amount (g/g) = (h1) - (h2)

<Weight average particle size>
Using a low-tap test sieve shaker and a standard sieve (JIS Z8801-1: 2006), the method described in Perry's Chemical Engineers Handbook 6th Edition (McGraw-Hill Book Company, 1984, page 21) measured in

<Production Example 1>
Acrylic acid (a1-1) {manufactured by Mitsubishi Chemical Corporation, purity 100%} 270 parts, cross-linking agent (b-1) {pentaerythritol triallyl ether, manufactured by Daiso Co., Ltd.} 0.98 parts and ion-exchanged water 712 The parts were kept at 3°C while stirring and mixing. After nitrogen was introduced into this mixture to reduce the dissolved oxygen content to 1 ppm or less, 1.1 parts of a 1% aqueous hydrogen peroxide solution, 2.0 parts of a 2% ascorbic acid aqueous solution and 2% 2,2'-azobis were added. 13.5 parts of an aqueous amidinopropane dihydrochloride solution was added and mixed to initiate polymerization. After the temperature of the mixture reached 80° C., it was aged at 80±2° C. for about 5 hours to obtain a hydrous gel.

Next, this water-containing gel was finely chopped with a mincing machine (12VR-400K manufactured by ROYAL), and 220 parts of a 49% sodium hydroxide aqueous solution was added and mixed and neutralized to obtain a neutralized gel. Furthermore, the neutralized hydrous gel is aerated and dried under the conditions of a supply temperature of 150 ° C. and a wind speed of 1.5 m / sec using a ventilation dryer (manufactured by Inoue Metal Industry) until the moisture content reaches 4%, and the dried body is obtained. Obtained. After pulverizing the dried product with a juicer mixer (Osterizer Blender manufactured by Oster), the particle size is adjusted using a sieve with an opening of 710 to 150 μm so that the average particle size is 400 μm, and the crosslinked polymer is included. Resin particles (A-1) were obtained.

Then, 100 parts of the obtained resin particles (A-1) were stirred at high speed (high-speed stirring turbulizer manufactured by Hosokawa Micron Corporation: number of rotations: 2000 rpm), and ethylene glycol diglycidyl ether as a surface cross-linking agent (d) was added thereto. .12 parts, 1.0 parts of propylene glycol, 1.0 parts of Klebosol 30cal 25 (colloidal silica manufactured by AZ Material Co., Ltd.) as water-insoluble inorganic fine particles (f), and 1.7 parts of ion-exchanged water, and A mixed solution obtained by mixing 0.6 parts of sodium aluminum sulfate dodecahydrate, 0.6 parts of propylene glycol and 1.5 parts of ion-exchanged water as a property improver was added at the same time, uniformly mixed, and then heated at 135°C for 30 minutes. After heating for a minute, surface-crosslinked resin particles (A-2) were obtained.

<Production Example 2>
Production Example 1 except that the surface cross-linking agent (d) used in 100 parts of the obtained resin particles (A-1) was changed to 0.20 parts of ethylene glycol diglycidyl ether and 1.5 parts of propylene glycol. A surface-crosslinked resin particle (A-3) similar to that was obtained.

<Production Example 3>
While chopping the water-containing gel used in Production Example 1 with a mincing machine (12VR-400K manufactured by ROYAL), 220 parts of a 49% sodium hydroxide aqueous solution was added and mixed and neutralized to obtain a neutralized gel. Furthermore, the neutralized hydrous gel is aerated and dried under the conditions of a supply temperature of 150 ° C. and a wind speed of 1.5 m / sec using a ventilation dryer (manufactured by Inoue Metal Industry) until the moisture content reaches 4%, and the dried body is obtained. Obtained. After pulverizing the dried product with a juicer mixer (Osterizer Blender manufactured by Oster), the particle size is adjusted using a sieve with an opening of 710 to 150 μm so that the average particle size is 300 μm, and the crosslinked polymer is included. Resin particles (A-4) were obtained.

<Production Example 4>
Production Example 1 except that the surface cross-linking agent (d) used in 100 parts of the obtained resin particles (A-4) was changed to 0.04 parts of ethylene glycol diglycidyl ether and 0.5 parts of propylene glycol. The same surface-crosslinked resin particles (A-5) as were obtained.

<Example 1>
While 100 parts of the resin particles (A-2) obtained in Production Example 1 were stirred at high speed (high-speed stirring turbulizer manufactured by Hosokawa Micron: number of rotations: 2000 rpm), polymonolaurate was added as a polyvalent hydroxyl group-containing compound (B-1). 5.0 parts of oxyethylene sorbitan (Tween 20, manufactured by Tokyo Chemical Industry Co., Ltd., SP value (unit omitted) 10.4, viscosity (unit omitted) 400) was added and mixed uniformly. After that, it was heated at 80° C. for 30 minutes to obtain absorbent resin composition particles (P-1) of the present invention.

<Example 2>
While 100 parts of the resin particles (A-2) obtained in Production Example 1 were stirred at high speed (high-speed stirring turbulizer manufactured by Hosokawa Micron Corporation: rotation speed of 2000 rpm), sorbitan monolaue was added as a polyvalent hydroxyl group-containing compound (B-2). 5.0 parts of rate (Span 20, manufactured by Tokyo Chemical Industry Co., Ltd., SP value (unit omitted) 12.8, viscosity (unit omitted) 5000) was added and mixed uniformly. After that, it was heated at 80° C. for 30 minutes to obtain absorbent resin composition particles (P-2) of the present invention.

<Example 3>
While 100 parts of the resin particles (A-5) obtained in Production Example 4 were stirred at high speed (high-speed stirring turbulizer manufactured by Hosokawa Micron: number of revolutions 2000 rpm), sorbitan monolaue was added as a polyvalent hydroxyl group-containing compound (B-2). 5.0 parts of rate (Span 20, manufactured by Tokyo Chemical Industry Co., Ltd., SP value (unit omitted) 12.8, viscosity (unit omitted) 5000) was added and mixed uniformly. After that, it was heated at 80° C. for 30 minutes to obtain absorbent resin composition particles (P-3) of the present invention.

<Example 4>
While 100 parts of the resin particles (A-2) obtained in Production Example 1 were stirred at high speed (high-speed stirring turbulizer manufactured by Hosokawa Micron: 2000 rpm), propylene glycol ( SP value (unit omitted) 15.9 and viscosity (unit omitted) 48) 5.0 parts were added and uniformly mixed. After that, it was heated at 80° C. for 30 minutes to obtain absorbent resin composition particles (P-4) of the present invention.

<Example 5>
While 100 parts of the resin particles (A-3) obtained in Production Example 2 were stirred at high speed (high-speed stirring turbulizer manufactured by Hosokawa Micron: number of revolutions 2000 rpm), sorbitan monolaue was added as a polyhydroxyl group-containing compound (B-3). 5.0 parts of rate (Span 20, manufactured by Tokyo Chemical Industry Co., Ltd., SP value (unit omitted) 12.8, viscosity (unit omitted) 5000) was added and mixed uniformly. After that, it was heated at 80° C. for 30 minutes to obtain absorbent resin composition particles (P-5) of the present invention.

<Example 6>
While 100 parts of the resin particles (A-2) obtained in Production Example 1 were stirred at high speed (high-speed stirring turbulizer manufactured by Hosokawa Micron: number of revolutions 2000 rpm), sorbitan monolaue was added as a polyvalent hydroxyl group-containing compound (B-3). 20.0 parts of rate (Span 20, manufactured by Tokyo Chemical Industry Co., Ltd., SP value (unit omitted) 12.8, viscosity (unit omitted) 5000) was added and mixed uniformly. After that, it was heated at 80° C. for 30 minutes to obtain absorbent resin composition particles (P-6) of the present invention.

<Comparative Example 1>
The resin particles (A-2) obtained in Production Example 1 were used as absorbent resin composition particles (R-1) for comparison.

<Comparative Example 2>
5.0 parts of glycerin was added to 100 parts of the resin particles (A-2) obtained in Production Example 1 while stirring at high speed (high-speed stirring turbulizer manufactured by Hosokawa Micron; number of revolutions: 2000 rpm), followed by uniform mixing. After that, it was heated at 80° C. for 30 minutes to obtain absorbent resin composition particles (R-2) for comparison.

<Comparative Example 3>
5.0 parts of D-sorbitol was added to 100 parts of the resin particles (A-2) obtained in Production Example 1 while stirring at high speed (high-speed stirring turbulizer manufactured by Hosokawa Micron: 2000 rpm), followed by uniform mixing. did. After that, it was heated at 80° C. for 30 minutes to obtain absorbent resin composition particles (R-3) for comparison.

<Comparative Example 4>
While 100 parts of the resin particles (A-2) obtained in Production Example 1 were stirred at high speed (high-speed stirring turbulizer manufactured by Hosokawa Micron: number of revolutions 2000 rpm), sorbitan monolaue was added as a polyvalent hydroxyl group-containing compound (B-3). 0.8 parts of rate (Spun 20, manufactured by Tokyo Kasei Kogyo Co., Ltd.) was added and mixed uniformly. After that, it was heated at 80° C. for 30 minutes to obtain absorbent resin composition particles (R-4) for comparison.

Preparation and Evaluation of Absorbent 100 parts of fluff pulp and 100 parts of the absorbent resin composition particles (P-1) obtained in Example 1 were mixed with an airflow mixing device {Pad Former manufactured by Autec Co., Ltd.}. After obtaining a mixture, this mixture was uniformly laminated on an acrylic plate (thickness 4 mm) so as to have a basis weight of about 500 g/m ² and pressed at a pressure of 5 kg/cm ² for 30 seconds to form an absorbent body. Obtained. This absorbent was cut into a rectangle of 10 cm x 40 cm, and water-absorbing paper having the same size as the absorbent (basis weight 15.5 g/m ² , manufactured by Advantech, filter paper No. 2) was placed above and below each, Furthermore, an absorbent article was prepared by placing a polyethylene sheet (polyethylene film UB-1 manufactured by Tamapoly Co., Ltd.) on the back and a nonwoven fabric (basis weight 20 g/m ² , Eltasguard manufactured by Asahi Kasei Co., Ltd.) on the surface. The dryness value was evaluated and the results are shown in Table 1.

Evaluation of surface dryness value by SDME method In an absorbent article {horse blood (Japan Lamb EDTA whole blood, 25 ° C.) in which the detector of the SDME (Surface Dryness Measurement Equipment) tester (manufactured by WK system) is sufficiently moistened The absorbent article was soaked in and left for 60 minutes to prepare. } and set the 0% dryness value, then set the detector of the SDME tester to a dry absorbent article {prepared by heating and drying the absorbent article at 80° C. for 2 hours. } and set 100% dryness to calibrate the SDME tester. Next, set a metal ring (inner diameter 70 mm, length 50 mm) in the center of the absorbent article to be measured, inject 80 ml of horse blood, and when it has finished absorbing {until the luster of horse blood cannot be confirmed}, Remove the ring, place the SDME detector on the center of the absorbent article, start measuring the surface dryness value, read the value 5 minutes after the start of measurement, 85% or more ◎, 70% or more and less than 85% was rated as ◯, and less than 70% was rated as x. The horse blood, the measurement atmosphere, and the leaving atmosphere were 25±5° C. and 65±10% RH.

(P-1) to the absorbent resin compositions (P-2) to (P-6) of Examples 2 to 6 and the absorbent resins (R-1) to (R-4) of Comparative Examples 1 to 4 , an absorbent body and an absorbent article were prepared in the same manner, except that each was changed. Table 1 shows the dryness evaluation results for each absorbent article obtained. In addition, the water retention capacity, weight average particle size, blood absorption capacity, and blood absorption rate were also measured by the methods described above. The results are also shown in Table 1.

As is clear from the results shown in Table 1, in Examples 1 to 6 containing the polyvalent hydroxyl group-containing compound (B), compared with Comparative Examples 1 to 3 not containing the polyvalent hydroxyl group-containing compound (B), The time (seconds) required for the blood to lose its fluidity after the blood is added is short, so the absorption speed is high, the blood water absorption capacity is high, and the absorption performance is excellent. On the other hand, in Comparative Example 4, in which the content of the polyvalent hydroxyl group-containing compound (B) is small, the value of the water absorption rate is higher than that in Examples, indicating that the absorption performance is inferior.

Claims (9)

A water-soluble vinyl monomer (a1) and/or a vinyl monomer (a2) that becomes a water-soluble vinyl monomer (a1) by hydrolysis as an essential structural unit, a surface-crosslinked polymer (A), and a solubility parameter of 8.5 ~17.0 (cal/cm ³ ) ^1/2 , a viscosity at 25°C of 20 to 7000 mPa s, and a polyvalent hydroxyl group-containing compound (B ), having the polyvalent hydroxyl group-containing compound (B) on the surface of the absorbent resin composition particle, and the polyvalent hydroxyl group-containing compound (B) being the 3.0 to 15% by weight based on the weight of the polymer (A), and the polyhydroxyl group-containing compound (B) is polyoxyethylene sorbitan monolaurate and/or sorbitan monolaurate resin composition particles. 2. The absorbent resin composition particles according to claim 1, wherein the water retention capacity of 0.9% by weight physiological saline is 20 to 60 g/g per unit weight. 3. The absorbent resin composition particles according to claim 1 or 2, having a weight average particle size of 150 to 500 μm. 4. The absorbent resin composition particles according to any one of claims 1 to 3, wherein the blood absorption ratio expressed by the blood absorption weight with respect to the weight of the absorbent resin composition particles is 10 to 25 times. 5. The method according to any one of claims 1 to 4, wherein the blood absorption rate expressed by the time (seconds) from when 1.0 g of blood is added to 0.2 g of the absorbent resin composition particles until the blood loses its fluidity is 120 seconds or less. The absorbent resin composition particles according to any one of the above. 6. The absorbent resin composition particles according to any one of claims 1 to 5, further comprising water-insoluble inorganic particles (f). 7. The absorbent resin composition particles according to claim 6, comprising two or more kinds of water-insoluble inorganic particles (f). An absorbent article using the absorbent resin composition particles according to any one of claims 1 to 7. 9. The absorbent article according to claim 8, which is used for absorbing blood.