JP2018021133A - Absorptive resin composition particles and method for producing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide absorptive resin composition particles having excellent effect of absorbing aqueous liquid, particularly blood.SOLUTION: There are provided absorptive resin composition particles that contain a polymer (A) containing a water-soluble vinyl monomer (a1) and/or a vinyl monomer (a2) converted into the water-soluble vinyl monomer (a1) by hydrolysis as essential constitutional units, and a polyvalent hydroxyl group-containing compound (B) having a solubility parameter of 7.0-19.0 (cal/cm)and viscosity at 25°C of 20-8,000 mPa s, and contains 1.0-20 wt.% of the polyvalent hydroxyl group-containing compound (B) based on the weight of the polymer (A); and a production method including a step of crosslinking the surface of the polymer (A) with a surface crosslinking agent (d), and then a step of mixing the polyvalent hydroxyl group-containing compound (B) therewith.SELECTED DRAWING: None

Description

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

  As a resin that absorbs bodily fluids used for sanitary materials, crosslinked polyacrylic acid partially neutralized products are known, and are widely used in disposable diapers and sanitary napkins. It is known that when the object to be absorbed is blood, unlike urine, there are many solid components such as blood cells, so there is little liquid, and in the case of menstrual blood, there is less liquid. Conventionally, a water-absorbent composite having excellent absorption performance for blood with high viscosity by adhering a water-insoluble inorganic substance or a water-insoluble hydrophilic fibrous substance to the surface of an absorbent resin in order to absorb blood Is known (see Patent Documents 1 and 2). In recent years, the addition of polyols and cationic metal salts during surface cross-linking in the process of manufacturing absorbent resins can exhibit high absorption capability under pressure, and powdery cross-linked absorption that absorbs aqueous liquids and blood. Polymers, their production methods (see Patent Document 3) and their use are known. However, even in these methods, there is a problem in the dryness of the absorbent body because the absorbent performance is not always sufficiently exerted with respect to a body fluid having a small amount of fluid such as blood.

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 having an excellent absorption effect for aqueous liquids, particularly blood.

The present invention includes a polymer (A) having 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 constituent unit, a solubility parameter [hereinafter referred to as SP. Also called value. ] Is 7.0 to 19.0 (cal / cm ³ ) ^1/2 and the polyvalent hydroxyl group-containing compound (B) has a viscosity at 25 ° C. of 20 to 8000 mPa · s. Absorbent resin composition particles, which are composition particles and contain 1.0 to 20% by weight of the polyvalent hydroxyl group-containing compound (B) based on the weight of the polymer (A), and blood absorption using the same An absorbent resin suitable for the production of absorbent resin composition particles comprising a step of mixing the polyvalent hydroxyl group-containing compound (B) after the step of crosslinking the surface of the polymer (A) with a surface crosslinking agent (d) Method.

  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 with respect to body fluids, particularly blood. Therefore, even in various usage situations, it exhibits excellent absorption performance stably against body fluids such as blood.

The absorbent resin composition particles of the present invention comprise a polymer (A) having 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 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. Absorbent resin composition particles.

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

  Vinyl monomer (a2) which becomes water-soluble vinyl monomer (a1) by hydrolysis [hereinafter also referred to as hydrolyzable vinyl monomer (a2). ] Is not particularly limited, and known {for example, vinyl monomers having at least one hydrolyzable substituent which 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 disclosed in paragraphs 0052 to 0055 of JP-A-2005-75982 Vinyl monomer having a group etc.] can be used. The water-soluble vinyl monomer is a concept well known to those skilled in the art, but when expressed in terms of quantity, for example, it means a vinyl monomer that dissolves in 100 g of water at 25 ° C. The hydrolyzability in the hydrolyzable vinyl monomer (a2) means, for example, the property of being hydrolyzed by the action of water and, if necessary, a catalyst (an acid or a base) to become water-soluble. Hydrolysis of the hydrolyzable vinyl monomer (a2) may be performed either during polymerization, after polymerization, or both of these, but from the viewpoint of the absorption performance of the aqueous liquid of the resulting absorbent resin composition particles, polymerization is performed. The latter 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, carbamoyl group are more preferable. , Vinyl monomers having an ammonio group or a mono-, di- or tri-alkylammonio group, more preferred are vinyl monomers having a carboxy (salt) group or a carbamoyl group, and particularly preferred is (meth) acrylic acid (salt). And (meth) acrylamide, particularly preferred is (meth) acrylic acid (salt), and most preferred is acrylic acid (salt).

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

  When either the water-soluble vinyl monomer (a1) or the hydrolyzable vinyl monomer (a2) is used as a structural unit, one kind of each may be used alone as a structural unit, and if necessary, two or more kinds may be used as a structural unit. good. The same applies when the water-soluble vinyl monomer (a1) and the hydrolyzable vinyl monomer (a2) are used as constituent 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)] is preferably 75/25 to 99/1. More preferably, it is 85/15 to 95/5, and particularly preferably 90/10 to 93/7. Within this range, the absorption performance is further improved.

  As a constituent unit of the polymer (A), in addition to the water-soluble vinyl monomer (a1) and the hydrolyzable vinyl monomer (a2), another vinyl monomer (a3) copolymerizable with these may be used as the constituent unit. it can. Other vinyl monomers (a3) may be used alone or in combination of two or more.

The other vinyl monomer (a3) is not particularly limited, and is known (for example, a hydrophobic vinyl monomer disclosed in paragraphs 0028 to 0029 of Japanese Patent No. 3648553, paragraph 0025 of Japanese Patent Laid-Open No. 2003-165883, and special features. Hydrophobic vinyl monomers and the like disclosed in paragraph 0058 of Kaikai 2005-75982 can be used. Specifically, for example, the following vinyl monomers (i) to (iii) can be used.
(I) C8-C30 aromatic ethylenic monomer Styrene such as styrene, α-methylstyrene, vinyltoluene and hydroxystyrene, and halogen substituted products of styrene such as vinylnaphthalene and dichlorostyrene.
(Ii) C2-C20 aliphatic ethylenic monomer Alkenes (ethylene, propylene, butene, isobutylene, pentene, heptene, diisobutylene, octene, dodecene, octadecene, etc.); and alkadienes (butadiene, isoprene, etc.) and the like.
(Iii) C5-C15 alicyclic ethylenic monomer Monoethylenically unsaturated monomer (such as pinene, limonene and indene); and polyethylene vinyl monomer [such as cyclopentadiene, bicyclopentadiene and ethylidene norbornene].

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

  The polymer (A) may be crosslinked with an internal crosslinking agent as necessary. The internal cross-linking agent is not particularly limited and is known (for example, a cross-linking agent having two or more ethylenically unsaturated groups disclosed in Japanese Patent No. 3648553, paragraphs 0031 to 0034, and a functional group capable of reacting with a water-soluble substituent. A cross-linking agent having at least one group and having 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, Japanese Patent Application Laid-Open No. 2003-165883 To a crosslinking agent having two or more ethylenically unsaturated groups, a crosslinking agent having two or more ethylenically unsaturated groups and a reactive functional group, and a crosslinking agent having two or more reactive substituents, The crosslinkable vinyl monomer disclosed in paragraph 0059 of Kaikai 2005-75982 and paragraphs 0015-0016 of JP-A-2005-95759 The indicated cross-linking agent of the crosslinkable vinyl monomer are) it can be used. Among these, from the viewpoint of absorption performance and the like, a crosslinking agent having two or more ethylenically unsaturated groups is preferable, and more preferable is triallyl cyanurate, triallyl isocyanurate, and a poly (poly (2 to 40 carbons) polyol). 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. An internal crosslinking agent may be used individually by 1 type, or may use 2 or more types together.

  As a polymerization method of the polymer (A), aqueous solution polymerization (adiabatic polymerization, thin film polymerization, spray polymerization method, etc .; JP-A-55-133413, etc.), known suspension polymerization methods and reverse phase suspension polymerization ( JP-B-54-30710, JP-A-56-26909 and JP-A-1-5808).

When aqueous solution polymerization is performed, a mixed solvent containing water and an organic solvent can be used. 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, dimethyl sulfoxide, and a mixture 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 reverse phase suspension polymerization method is employed, the polymerization may be carried out in the presence of a conventionally known dispersant or surfactant. In the case of the reverse phase suspension polymerization method, polymerization can be carried out using a hydrocarbon solvent such as xylene, normal hexane and normal heptane.

In the case of using an initiator for polymerization, an initiator for radical polymerization can be used. For example, azo compounds [azobisisobutyronitrile, azobiscyanovaleric acid, 2,2′-azobis (2-amidinopropane) hydrochloride, etc. ], Inorganic peroxides (hydrogen peroxide, ammonium persulfate, potassium persulfate, sodium persulfate, etc.), organic peroxides [benzoyl peroxide, di-t-butyl peroxide, cumene hydroperoxide, succinic acid peroxide] And di (2-ethoxyethyl) peroxydicarbonate, etc.] and redox catalyst (alkali metal sulfite or bisulfite, ammonium sulfite, ammonium bisulfite, ascorbic acid, etc., reducing agent and alkali metal persulfate, With oxidizing agents such as ammonium sulfate, hydrogen peroxide and organic peroxide And the like). These catalysts may be used alone or in combination of two or more thereof.
The amount (% by weight) of the radical polymerization initiator used is that of the water-soluble vinyl monomer (a1) and the hydrolyzable vinyl monomer (a2), when the other vinyl monomer (a3) is used (a1) to (a3). Based on the total weight, 0.0005 to 5 is preferable, and 0.001 to 2 is more preferable.

At the time of polymerization, a polymerization control agent typified by a chain transfer agent may be used as necessary. Specific examples thereof include sodium hypophosphite, sodium phosphite, alkyl mercaptans, alkyl halides. And thiocarbonyl compounds. These polymerization control agents may be used alone or in combination of two or more thereof.
The amount (% by weight) of the polymerization control agent used is that of the water-soluble vinyl monomer (a1) and the hydrolyzable vinyl monomer (a2), in the case of using other vinyl monomers (a3) (a1) to (a3), Based on the total weight, 0.0005 to 5 is preferable, and 0.001 to 2 is more preferable.

  The polymerization start 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 using a solvent (such as an organic solvent and water) for the polymerization, the solvent is preferably distilled off after the polymerization. When the solvent contains an organic solvent, the content (% by weight) of the organic solvent after the distillation is preferably 0 to 10, more preferably 0 to 5, particularly preferably based on the weight of the polymer (A). 0-3, most preferably 0-1. Within this range, the absorbent performance of the absorbent resin composition particles is further improved.

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

  The polymer (A) can be obtained by polymerizing a monomer composition having the water-soluble vinyl monomer (a1) and / or the hydrolyzable vinyl monomer (a2) as essential constituent components. Preferred is an aqueous solution polymerization method that does not require the use of an organic solvent or the like and is advantageous in terms of production cost, and more preferred is an aqueous liquid absorbent resin that has a large amount of water retention and a small amount of water-soluble components, An aqueous solution adiabatic polymerization method that does not require temperature control during polymerization is most preferable.

A water-containing gel-like product (hereinafter abbreviated as a water-containing gel) can be obtained by the above-described polymerization method, and the polymer (A) is obtained by further surface-crosslinking the particulate polymer obtained by drying the water-containing gel as necessary. It can also be obtained. When an acid group-containing monomer such as acrylic acid or methacrylic acid is used as the water-soluble vinyl monomer (a1), the hydrogel may be neutralized with a base. The neutralization degree of the acid group is preferably 50 to 80 mol%. When the degree of neutralization is less than 50 mol%, the resulting water-containing gel polymer has high tackiness, and the workability during production and use may deteriorate. Further, the water retention amount of the obtained aqueous liquid absorbent resin may be reduced. On the other hand, when the degree of neutralization exceeds 80%, the pH of the obtained resin becomes high, and there is a concern that the safety of human skin may be concerned.
The neutralization may be performed at any stage after the polymerization of the monomer composition in the production of the absorbent resin composition particles. For example, a method of neutralization in the state of a hydrous gel is exemplified as a preferred example. Is done.
As the base to be neutralized, alkali metal hydroxides such as sodium hydroxide and potassium hydroxide, and alkali metal carbonates such as sodium carbonate, sodium hydrogen carbonate and potassium carbonate can be used.

  The water-containing gel obtained by polymerization can be shredded as necessary before drying. The size (longest diameter) of the gel after chopping 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 drying property in the drying process is further improved.

  Shredding can be performed by a known method, and can be performed using a normal shredding device (for example, a bex mill, rubber chopper, pharma mill, mincing machine, impact crusher, and roll crusher). .

  In addition, the content of the organic solvent and the water content are as follows: Infrared moisture meter [JE400 manufactured by KETT Co., Ltd .: 120 ± 5 ° C., 30 minutes, atmospheric humidity before heating 50 ± 10% RH, lamp specification 100V, 40W] is obtained from the weight loss of the measurement sample when heated.

  As a method of distilling off the solvent (including water) of the hydrogel 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, a drying method using infrared rays, decantation, filtration, and the like can be applied. Moreover, although it does not specifically limit about drying time, From a viewpoint of deterioration of the gel by overdrying, 0 to 3 hours are preferable and 0 to 30 minutes are still more preferable.

The shape and particle size of the polymer (A) can be controlled by pulverization and classification as required. Examples of the shape of the polymer (A) include an irregularly crushed shape, a flake shape, a pearl shape, and a rice grain shape. Among these, from the viewpoint of good entanglement with the fibrous material in the use of paper diapers and the like and no fear of dropping off from the fibrous material, an irregular crushed shape is preferable.
The pulverization method is not particularly limited, and a normal pulverizer (for example, a hammer pulverizer, an impact pulverizer, a roll pulverizer, and a shet airflow pulverizer) can be used. The pulverized polymer can be adjusted in particle size by sieving if necessary.

The weight average particle diameter (μm) of the polymer (A) is preferably 100 to 500, more preferably 150 to 480, and particularly preferably 200 to 450. Within this range, the absorbent 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, and more preferably 1 or less. The content of the fine particles can be determined using a graph created when determining the above-mentioned weight average particle diameter.

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

  The polymer (A) may contain some other components such as a residual solvent and a residual crosslinking component as long as the performance is not impaired.

  The polymer (A) of the present invention can have a structure in which the surface is crosslinked with a surface crosslinking 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 amount and the absorption amount under load of the absorbent resin composition particles can be satisfied. It is preferable because it is possible. Examples of the surface cross-linking agent (d) include known polyvalent glycidyl compounds, polyvalent amines, polyvalent aziridine compounds and polyvalent isocyanate compounds described in JP 59-189103 A, JP 58-180233 A. And polyhydric alcohols described in JP-A-61-16903, silane coupling agents described in JP-A-61-211305 and JP-A-61-252212, and JP-A-5-508425. Alkylene carbonate, polyvalent oxazoline compounds described in JP-A No. 11-240959, and surface cross-linking agents such as polyvalent metals described in JP-A Nos. 51-136588 and 61-257235 can be used. Of these surface cross-linking agents, from the viewpoint of economy and absorption characteristics, polyvalent glycidyl compounds, polyhydric alcohols and polyvalent Mines are preferred, more preferred are polyvalent glycidyl compounds and polyhydric alcohols, particularly preferred are polyvalent glycidyl compounds, and most preferred are ethylene glycol diglycidyl ethers. It may be good, and 2 or more types may be used together.

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

  The surface crosslinking of the polymer (A) can be performed by mixing the polymer (A) and the surface crosslinking agent (d) and heating as necessary. As a mixing method of the polymer (A) and the surface cross-linking agent (d), a cylindrical mixer, a screw mixer, a screw extruder, a turbulator, a nauter mixer, a double-arm kneader, a fluid type Polymer (A) using a mixing device such as a mixer, a V-type mixer, a minced mixer, a ribbon-type mixer, a fluid-type mixer, an airflow-type mixer, a rotating disk-type mixer, a conical blender, and a roll mixer And a method of uniformly mixing the surface crosslinking agent (d). At this time, the surface crosslinking agent (d) may be used after diluted with water and / or an arbitrary solvent.

  Although the temperature at the time of mixing a polymer (A) and a surface crosslinking agent (d) is not specifically limited, 10-150 degreeC is preferable, More preferably, it is 20-100 degreeC, Especially preferably, it is 25-80 degreeC.

  After the polymer (A) and the surface crosslinking agent (d) are mixed, the surface-crosslinked polymer (A) can be usually obtained by performing a heat treatment. The heating temperature is preferably 100 to 180 ° C., more preferably 110 to 175 ° C., and particularly preferably 120 to 170 ° C. from the viewpoint of breakage resistance of the resin particles. Heating at 180 ° C. or lower is advantageous in terms of equipment because indirect heating using steam is possible, and absorption performance may deteriorate at heating temperatures below 100 ° C. Moreover, although heating time can be suitably set with heating temperature, from a viewpoint of absorption performance, Preferably it is 5 to 60 minutes, More preferably, it is 10 to 40 minutes. The surface-crosslinked polymer (A) can be further surface-crosslinked using the same or different surface cross-linking agent as the surface cross-linking agent used first.

  The polymer (A) obtained by surface cross-linking is sieved as necessary to adjust the particle size. The weight average particle size of the obtained particles is preferably 100 to 500 μm, more preferably 200 to 450 μm. The content of fine particles is preferably small, 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. As a method of treating with a hydrophobic substance, the method described in JP2013-231199A or the like may 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. A polyhydric 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 a blood absorption effect is obtained by having a plurality of hydroxyl groups. 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 alone 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 value of the solubility parameter (SP) is obtained by the following equation.
SP = (ΔH / V) ^1/2

In the formula, ΔH represents the heat of molar evaporation (cal / mol), and V represents the molar volume (cm ³ / mol). ΔH and V are the heat of molar evaporation (Δei) of the atomic group described in “POLYMER ENGINEERING AND SCIENCE, February, 1974, Vol. 14, No. 2, Robert F. Fedors. And the sum (V) of molar volumes (Δvi) can be used.

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

  The polyhydric hydroxyl group-containing compound (B) is a compound having a polyhydric 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 characteristics, 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, 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) is particularly preferable. 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 (unit saving) ) 13.6, viscosity 48 mPa · s), propylene glycol (SP value (unit omitted) 15.9, viscosity 48 mPa · s), 1,2-butanediol (SP value (unit omitted) 14.8, viscosity 40 mPa · s) 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), 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 a polyvalent hydroxyl group-containing compound (B) on the surface of the resin particles. When the polyvalent hydroxyl group-containing compound (B) is present on the surface of the resin particles, the affinity with blood can be improved, and as a result, the absorption characteristics for blood can be further enhanced. For this reason, it is preferable to add the polyvalent hydroxyl group-containing compound (B) after the surface crosslinking 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, and 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). As a mixing method, a cylindrical mixer, a screw type mixer, a screw type extruder, a turbulizer, a nauter type mixer, a double arm type kneader, a fluid type mixer, a V type mixer, a minced mixer, a ribbon type The method of uniformly mixing using well-known mixing apparatuses, such as a mixer, a fluid-type mixer, an airflow type mixer, a rotary disk type mixer, a conical blender, and a roll mixer, is mentioned.

  In mixing the polymer (A) and the polyvalent hydroxyl group-containing compound (B), it is preferable to add 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 a solvent. When the polyvalent hydroxyl group-containing compound (B) is added simultaneously with water and / or a solvent, a solution in which the polyvalent hydroxyl group-containing compound (B) is dissolved in water and / or a solvent or the polyvalent hydroxyl group-containing compound (B) is added with water and A dispersion dispersed in a solvent can be added, and a solution is preferably added from the viewpoint of workability and the like, and a solution dissolved in water is more preferable. When adding a solution or a dispersion, it is preferable to add by spraying or dripping.

  When using the aqueous solution which melt | dissolved the polyhydric hydroxyl group containing compound (B) in water, content of the polyhydric hydroxyl group containing compound (B) contained in aqueous solution is 5-5 with respect to the total weight of aqueous solution from a viewpoint of a blood absorption rate. It is preferably 70% by weight, more preferably 10 to 60% by weight. When the concentration is lower than the above range, the polyvalent hydroxyl group-containing compound (B) penetrates into the polymer and the blood absorption rate decreases, and when the concentration is high, the polymer becomes non-uniform.

  The type of the 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.

  20-140 degreeC is preferable and, as for the temperature at the time of mixing a polymer (A) and a polyvalent hydroxyl-containing compound (B), More preferably, it is 40-120 degreeC.

  In the case of heating after mixing the polymer (A) and the polyvalent hydroxyl group-containing compound (B), the heating time can be appropriately set depending on the heating temperature, but from the viewpoint of absorption performance, preferably 5 to 60 minutes, Preferably it is 10 to 40 minutes.

  The absorbent resin composition particles of the present invention may be used after the polymer (A) and the polyvalent hydroxyl group-containing compound (B) are mixed and sieved to adjust the particle size. The weight average particle size of the 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 containing the water-insoluble inorganic particles (f), the surface of the particles contained in the absorbent resin composition particles is subjected to a surface treatment with the water-insoluble inorganic particles (f), so that the blocking resistance of the absorbent resin composition particles and Improves fluid permeability.

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

  The amount (parts by weight) of the water-insoluble inorganic particles (f) used 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 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). 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 performed after mixing the polyvalent hydroxyl group-containing compound (B). The particle size after particle size adjustment is the same.

  The absorbent resin composition particles of the present invention may contain additives (for example, known preservatives, fungicides, antibacterial agents (for example, described in JP-A Nos. 2003-225565 and 2006-131767)) , Antioxidants, ultraviolet absorbers, colorants, fragrances, deodorants, liquid permeability improvers, organic fibrous materials, and the like. 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 based on the weight of the polymer (A). Is 0.05 to 1, most preferably 0.1 to 0.5.

  The production method of the present invention includes a step of mixing the polymer (A) and the 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 the step of mixing the polymer (A) and the polyvalent hydroxyl group-containing compound (B), preferably a solution thereof, as described above. It can carry out by mixing using a well-known mixing apparatus. The temperature during mixing is preferably 100 to 140 ° C, more preferably 100 to 120 ° C. By setting it as the solution of a polyhydric hydroxyl group containing compound (B), a polymer (A) and a polyhydric hydroxyl group containing compound (B) can be mixed uniformly, and quality is stabilized. It is preferable to mix the polyvalent hydroxyl group-containing compound (B) after the surface of the polymer (A) is crosslinked with a surface crosslinking agent (d). 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, and further preferably 3 to 8% by weight from the viewpoint of absorption characteristics.
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, and particularly preferably 0.56 to 0.66. It is. Within this range, the function of fixing the absorbent resin (gel) swollen due to urination of the absorbent article or the like is further improved. The apparent density of the absorbent resin composition particles is measured at 25 ° C. in accordance with JIS K7365: 1999.

  The water retention amount (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 more is even more preferable. The upper limit is preferably 60 or less, and more preferably 55 or less, from the viewpoint of the amount of absorption under load. The water retention amount can be appropriately adjusted by the amount (% by weight) of the surface cross-linking agent (d) used.

  The absorbency of blood represented by the absorbed weight of blood relative to the weight of the absorbable resin composition particles of the absorbable resin composition particles of the present invention can be measured by the method described later, and the viewpoint of the dryness of the absorber Therefore, it is preferably 2 times or more, more preferably 4 times or more, and still more preferably 10 times or more. Further, the upper limit is preferably 25 times or less, more preferably 20 times or less, from the viewpoint of the amount of absorption under load.

  The blood absorption rate in terms of time (seconds) from the introduction of 1.0 g of blood into 0.2 g of the absorbent resin composition particles in the present invention until the disappearance of blood fluidity is From the viewpoint of the dryness of the absorber, 120 seconds or less is preferable, more preferably 100 seconds or less, and still 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 later, and is preferably 2,000 or more, more preferably 2,000 or more, and 2,050 from the viewpoint of the amount absorbed under load. The above is even more preferable. The upper limit is preferably 4,000 or less, more preferably 3,900 or less, and even more preferably 3,700 or less, from the viewpoint of absorption performance.

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

  The absorbent body in which the absorbent resin composition particles of the present invention are used is excellent in the absorption amount of body fluids such as blood, excellent in the uptake speed of the liquid, and excellent in dry touch properties under pressure after absorption, Cracks and deformation can be suppressed.

  The absorber using the absorbent resin composition particles includes, for example, absorbent resin composition particles and hydrophilic fibers. Specific examples of the hydrophilic fiber include wood pulp fibers such as mechanical pulp, chemical pulp, semi-chemical pulp, and dissolved pulp from wood, and artificial cellulose fibers such as rayon and acetate. A preferred hydrophilic fiber is wood pulp fiber. These hydrophilic fibers may partially contain synthetic fibers such as nylon and polyester.

  The content of the absorbent resin composition particles in the absorber is preferably 5 to 95% by mass, more preferably 20 to 90% by mass, and more preferably 30 to 80% by mass from the viewpoint of light weight and thin film formation. % Is more preferable.

  The constitution of the absorbent is as follows: 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 with a tissue. The absorbent body may contain other components, for example, an adhesive binder such as a heat-fusible synthetic fiber, a hot melt adhesive, and an adhesive emulsion for enhancing the shape retention of the absorbent body. .

  Also, 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, it can be set as an absorptive article. The liquid permeable sheet is disposed on the side in contact with the body, and the liquid impermeable sheet is disposed on the opposite side in contact with the body.

  Examples of the liquid permeable sheet include air-through type, spun bond 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 the liquid impermeable sheet include synthetic resin films made of resins such as polyethylene, polypropylene, and polyvinyl chloride.

  Hereinafter, although an example and a comparative example explain the present invention further, the present invention is not limited to these. Unless otherwise specified, “part” means “part by weight” and “%” means “% by weight”. In addition, the water retention amount with respect to the physiological saline of the absorbent resin composition particles, the blood absorption rate, the blood absorption rate, and the weight average molecular weight were measured at 25 ± 2 ° C. by the following method.

<Absorption rate of blood>
A sample of 0.1 g was added to a nylon mesh bag and heat-sealed on all sides. In advance, 15 g of horse blood was prepared in a beaker, and a nylon mesh bag containing the sample was immersed for 15 minutes. After 15 minutes, the nylon mesh was taken out and suspended for 1 minute to remove excess blood, and the weight was measured. The blood absorption rate was a value obtained by subtracting a value obtained by subtracting the weight before absorption and the absorption amount when only the nylon mesh was immersed from the weight after blood absorption.

<Blood absorption rate>
Spread 0.2 g of sample uniformly over the bottom of a 9 ml screw vial and measure the time (seconds) from the time when 1.0 g of equine blood is added to the end of the blood flow of equine blood. Absorption rate (seconds). In this measurement, the loss of fluidity means that there is no blood flowing independently of the sample when the bottom surface of the screw vial is inclined 45 degrees with respect to the horizontal. Therefore, even if blood absorbed in the sample exists on the surface of the sample, if there is no blood flowing independently of the sample, it is determined that there is no fluidity.

<Measurement method of water retention amount>
1.00 g of a measurement sample is placed in a tea bag (20 cm long, 10 cm wide) made of a nylon net having a mesh size of 63 μm (JIS Z8801-1: 2006) and in 1,000 ml of physiological saline (saline concentration 0.9%). The sample was immersed for 1 hour without stirring and then pulled up, suspended for 15 minutes and drained. Thereafter, each tea bag was placed in a centrifuge, centrifuged at 150 G for 90 seconds to remove excess physiological saline, the weight (h1) including the tea bag was measured, and the water retention amount was determined from the following equation. In addition, the temperature of the used physiological saline and measurement atmosphere was 25 degreeC +/- 2 degreeC. (H2) is the weight of the tea bag measured by the same operation as described above when there is no measurement sample.
Water retention amount (g / g) = (h1)-(h2)

<Weight average particle diameter>
Using the low-tap test sieve shaker and standard sieve (JIS Z8801-1: 2006), the method described in Perry's Chemical Engineers Handbook 6th Edition (McGlow Hill Book Campany, 1984, p. 21) Measured with

<Production Example 1>
Acrylic acid (a1-1) {Mitsubishi Chemical Co., Ltd., purity 100%} 270 parts, Crosslinker (b-1) {Pentaerythritol triallyl ether, manufactured by Daiso Corporation} 0.98 parts and ion-exchanged water 712 The part was kept at 3 ° C. with stirring and mixing. After flowing nitrogen into this mixture to reduce the dissolved oxygen amount to 1 ppm or less, 1.1 parts of 1% aqueous hydrogen peroxide solution, 2.0 parts of 2% aqueous ascorbic acid solution, and 2% 2,2′-azobis Polymerization was initiated by adding and mixing 13.5 parts of an amidinopropane dihydrochloride aqueous solution. After the temperature of the mixture reached 80 ° C., it was aged at 80 ± 2 ° C. for about 5 hours to obtain a water-containing gel.

  Next, while this hydrated gel was shredded with a mincing machine (12VR-400K manufactured by ROYAL), 220 parts of 49% sodium hydroxide aqueous solution was added and mixed and neutralized to obtain a neutralized gel. Further, the neutralized water-containing gel was air-dried using a ventilation-type dryer (manufactured by Inoue Metal) under the conditions of a supply temperature of 150 ° C. and a wind speed of 1.5 m / sec until the water content became 4%. Obtained. After the dried product is pulverized with a juicer mixer (Osterizer BLENDER manufactured by Oster), the particle size is adjusted using a sieve having an opening of 710 to 150 μm so that the average particle size becomes 400 μm, and contains a crosslinked polymer. Resin particles (A-1) were obtained.

  Subsequently, 100 parts of the obtained resin particles (A-1) were stirred at a high speed (high-speed stirring turbulizer manufactured by Hosokawa Micron: rotation speed: 2000 rpm), and ethylene glycol diglycidyl ether 0 as a surface cross-linking agent (d) was added thereto. .. 12 parts, 1.0 part of propylene glycol, 1.0 part of Klebosol 30cal25 (colloidal silica manufactured by AZ Materials) as water-insoluble inorganic fine particles (f) and 1.7 parts of ion-exchanged water, and liquid flow A mixture of sodium aluminum sulfate dodecahydrate 0.6 part, propylene glycol 0.6 part and ion-exchanged water 1.5 part as a property improver was added at the same time and mixed uniformly. Heating was performed for minutes to obtain surface-crosslinked resin particles (A-2).

<Production Example 2>
Production Example 1 except that the surface cross-linking agent (d) used for 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, respectively. The same surface-crosslinked resin particles (A-3) were obtained.

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

<Production Example 4>
Production Example 1 except that the surface cross-linking agent (d) used for 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, respectively. The same surface-crosslinked resin particles (A-5) 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: rotation speed: 2000 rpm), polylauric acid poly (polyurethane-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. Then, it heated at 80 degreeC for 30 minute (s), and obtained the absorbent resin composition particle | grains (P-1) of this invention.

<Example 2>
While 100 parts of the resin particles (A-2) obtained in Production Example 1 were stirred at a high speed (high-speed stirring turbulizer manufactured by Hosokawa Micron: rotation speed 2000 rpm), sorbitan monolaur as a polyvalent hydroxyl group-containing compound (B-2) 5.0 parts of a rate (Span 20, manufactured by Tokyo Chemical Industry Co., Ltd., SP value (unit omitted) 12.8, viscosity (unit omitted) 5000) were added and mixed uniformly. Then, it heated at 80 degreeC for 30 minute (s), and obtained the absorbent resin composition particle | grains (P-2) of this 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: rotation speed: 2000 rpm), sorbitan monolaur as a polyvalent hydroxyl group-containing compound (B-2) 5.0 parts of a rate (Span 20, manufactured by Tokyo Chemical Industry Co., Ltd., SP value (unit omitted) 12.8, viscosity (unit omitted) 5000) were added and mixed uniformly. Then, it heated at 80 degreeC for 30 minute (s), and obtained the absorbent resin composition particle | grains (P-3) of this 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: rotation speed 2000 rpm), propylene glycol (polyhydric hydroxyl group-containing compound (B-3)) SP value (unit omitted) 15.9 and viscosity (unit omitted) 48) 5.0 parts were added and mixed uniformly. Then, it heated at 80 degreeC for 30 minute (s), and obtained the absorbent resin composition particle | grains (P-4) of this 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: rotation speed 2000 rpm), sorbitan monolaur as a polyvalent hydroxyl group-containing compound (B-3) 5.0 parts of a rate (Span 20, manufactured by Tokyo Chemical Industry Co., Ltd., SP value (unit omitted) 12.8, viscosity (unit omitted) 5000) were added and mixed uniformly. Then, it heated at 80 degreeC for 30 minute (s), and obtained the absorbent resin composition particle | grains (P-5) of this invention.

<Example 6>
While 100 parts of the resin particles (A-2) obtained in Production Example 1 were stirred at a high speed (high-speed stirring turbulizer manufactured by Hosokawa Micron: 2,000 rpm), sorbitan monolaur as a polyvalent hydroxyl group-containing compound (B-3). 20.0 parts of a rate (Span 20, manufactured by Tokyo Chemical Industry Co., Ltd., SP value (unit omitted) 12.8, viscosity (unit omitted) 5000) were added and mixed uniformly. Then, it heated at 80 degreeC for 30 minute (s), and obtained the absorbent resin composition particle | grains (P-6) of this invention.

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

<Comparative 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: rotation speed 2000 rpm), 5.0 parts of glycerin was added and mixed uniformly. Then, it heated at 80 degreeC for 30 minute (s), and obtained the absorbent resin composition particle (R-2) for a comparison.

<Comparative Example 3>
While stirring 100 parts of the resin particles (A-2) obtained in Production Example 1 at a high speed (high speed stirring turbulizer manufactured by Hosokawa Micron: rotation speed 2000 rpm), 5.0 parts of D-sorbitol is added and mixed uniformly. did. Then, it heated at 80 degreeC for 30 minute (s), and obtained the absorbent resin composition particle (R-3) for a comparison.

<Comparative Example 4>
While 100 parts of the resin particles (A-2) obtained in Production Example 1 were stirred at a high speed (high-speed stirring turbulizer manufactured by Hosokawa Micron: 2,000 rpm), sorbitan monolaur as a polyvalent hydroxyl group-containing compound (B-3). 0.8 parts of a rate (Span 20, manufactured by Tokyo Chemical Industry Co., Ltd.) was added and mixed uniformly. Then, it heated at 80 degreeC for 30 minute (s), and obtained the absorbent resin composition particle (R-4) for a comparison.

Preparation and Evaluation of Absorber 100 parts of fluff pulp and 100 parts of absorbent resin composition particles (P-1) obtained in Example 1 were mixed with an airflow type mixing device {Pad former manufactured by Autech Co., Ltd.}. The mixture is 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. Obtained. The absorbent body is cut into a 10 cm × 40 cm rectangle, and water absorbent paper (basis weight 15.5 g / m ² , manufactured by Advantech Co., Ltd., filter paper No. 2) having the same size as the absorbent body is arranged above and below each of the absorbent bodies. Further, an absorbent article was prepared by arranging a polyethylene sheet (polyethylene film UB-1 manufactured by Tamapoly Co., Ltd.) on the back surface and a non-woven fabric (basis weight 20 g / m ² , Eltas Guard manufactured by Asahi Kasei Co., Ltd.) on the surface. Dryness values were evaluated and the results are shown in Table 1.

Evaluation of surface dryness value by the SDME method In an absorbent article {Horse blood (Japan Lamb EDTA whole blood, 25 ° C) fully moistened with the detector of the SDME (Surface Dryness Measurement Equipment) tester (manufactured by WK system) The absorbent article was soaked in and prepared for 60 minutes. }, And a 0% dryness value was set. Then, the detector of the SDME tester was dried to prepare an absorbent article {absorbent article was heated and dried at 80 ° C. for 2 hours. } Was set to 100% dryness, and the SDME tester was calibrated. Next, a metal ring (inner diameter 70 mm, length 50 mm) is set in the center of the absorbent article to be measured, 80 ml of horse blood is injected, and after absorption is completed {until no gloss can be confirmed by horse blood}, the metal is immediately Remove the ring, place the SDME detector in 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 marked with ○ and less than 70% was marked with ×. The horse blood, the measurement atmosphere and the standing 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 The absorbent body and the absorbent article were adjusted in the same manner except that each was changed. Table 1 shows the results of dryness evaluation for each of the obtained absorbent articles. Further, the water retention amount, the weight average particle diameter, the blood absorption rate, and the blood absorption rate were also measured by the above-described methods. 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) from the introduction of blood to the disappearance of blood fluidity is small. Therefore, the absorption rate is high, the blood water absorption ratio is high, and the absorption performance is excellent. On the other hand, it can be seen that Comparative Example 4 having a small content of the polyvalent hydroxyl group-containing compound (B) has a higher water absorption rate than the Examples, and the absorption performance is inferior.

Claims (12)

A polymer (A) having a water-soluble vinyl monomer (a1) and / or a vinyl monomer (a2) which becomes a water-soluble vinyl monomer (a1) by hydrolysis as an essential constituent unit, and a solubility parameter of 7.0 to 19.0 (Cal / cm ³ ) ^1/2 , and an absorptive resin composition particle containing a polyvalent hydroxyl group-containing compound (B) having a viscosity at 25 ° C. of 20 to 8000 mPa · s. Absorbent resin composition particles containing 1.0 to 20% by weight of the hydroxyl group-containing compound (B) based on the weight of the polymer (A).   The absorbent resin composition particle according to claim 1, wherein a water retention amount of 0.9 wt% physiological saline is 20 to 60 g / g per unit weight.   The absorbent resin composition particles according to claim 1 or 2, wherein the weight average particle diameter is 150 to 500 µm.   The absorptive resin composition particles according to any one of claims 1 to 3, wherein the absorption ratio of blood expressed by the absorbed weight of blood with respect to the weight of the absorptive resin composition particles is 10 to 25 times.   The blood absorption rate expressed in time (seconds) from the introduction of 1.0 g of blood into 0.2 g of the absorbent resin composition particles until the blood fluidity is lost is 120 seconds or less. Absorbent resin composition particles according to any one of the above.   The absorbent resin composition particle according to any one of claims 1 to 5, wherein the polyvalent hydroxyl group-containing compound (B) is a compound having 2 to 3 hydroxyl groups.   The absorbent resin composition particle according to any one of claims 1 to 6, wherein the surface of the polymer (A) is crosslinked with a surface crosslinking agent (d).   Furthermore, the absorptive resin composition particle | grains in any one of Claims 1-7 containing a water-insoluble inorganic particle (f).   Absorbent resin composition particles according to claim 8, comprising two or more types of water-insoluble inorganic particles (f).   An absorbent article using the absorbent resin composition particles according to claim 1.   The absorbent article according to claim 10, which is for blood absorption.   The surface of the polymer (A) having the water-soluble vinyl monomer (a1) and / or the vinyl monomer (a2) which becomes the water-soluble vinyl monomer (a1) by hydrolysis as an essential constituent unit is cross-linked by the surface cross-linking agent (d). The manufacturing method of the absorbent resin composition particle | grain characterized by including the process of mixing a polyhydric-hydroxyl group containing compound (B) after a process.