JP4493429B2 - Water-absorbing resin composition and method for producing the same, and absorbent body and absorbent article using the same - Google Patents

Description

  The present invention relates to a water absorbent resin composition, an absorbent body, an absorbent article, and a method for producing the water absorbent resin composition. More specifically, the present invention exhibits excellent hygroscopic fluidity, low separability, deodorization performance, gel strength, and absorption performance when used in sanitary materials such as paper diapers, sanitary napkins, and incontinence pads. The present invention relates to a water absorbent resin composition, an absorbent body, and an absorbent article. Moreover, this invention relates to the manufacturing method of the water absorbing resin composition which has such a characteristic.

  Water-absorbent resins are widely used in sanitary materials such as disposable diapers, sanitary napkins and incontinence pads for the purpose of absorbing body fluids such as urine and blood, and are the main constituent materials of these sanitary materials. ing.

  In recent years, especially with the growing demand for disposable diapers for adults due to the aging of society, it is possible to impart deodorizing performance to water-absorbent resins, in particular, to remove malodors originating from sulfur compounds such as hydrogen sulfide and mercaptans. There is an increasing demand for imparting deodorant performance.

  As a technique for imparting deodorant performance to the water absorbent resin, a combination of the water absorbent resin and various deodorants and antibacterial agents has been proposed. For example, a water-absorbing resin composition comprising a water-absorbing resin and a leaf extract of a camellia plant (see, for example, Patent Document 1), a coniferous tree extract and a water-absorbing resin having specific performance. Product (see, for example, Patent Document 2), deodorant resin composition in which zeolite particles are dispersed inside a water-absorbent resin (see, for example, Patent Document 3), water-absorbent resin, and one kind selected from titanium or zirconium A water-absorbent resin composition (for example, see Patent Document 4) comprising a metal hydrous oxide comprising at least one selected from zinc, aluminum, calcium, magnesium, and silicon, a water-absorbent resin, and oxalic acid A water-absorbent resin composition comprising a salt compound and a composite silicate compound (see, for example, Patent Document 5), a water-absorbent resin, a tannate, and a composite silicate compound. A water-absorbing resin composition (for example, see Patent Document 6), a water-absorbing resin, a glycine-type amphoteric surfactant, and a composite silicate compound (for example, see Patent Document 7) ), A water-absorbent resin composition comprising a water-absorbent resin, a sulfur-containing reducing agent, and a composite silicate compound (for example, see Patent Document 8).

  A technique for imparting deodorant performance to an absorbent article using a water absorbent resin has also been studied, for example, tea making, and an absorbent article made of a water absorbent resin (see, for example, Patent Document 9), a water absorbent resin, Disposable diapers (for example, see Patent Document 10) containing a resin composed of benzalkonium chloride and / or chlorhexidine gluconate, hygiene products in which a water-absorbing resin and zinc aluminosilicate are combined (for example, see Patent Document 11), etc. It has been known.

  Furthermore, studies have been made to impart both deodorizing performance and powder handling properties to the water-absorbent resin. For example, a water-absorbing agent comprising a water-absorbing resin, a compound having an antibacterial function against ammonia-producing bacteria, and a drug having neutralizing ability or neutralizing ability and adsorbing ability with respect to ammonia (see, for example, Patent Document 12) )It has been known. Regarding the water absorbent resin, in addition to the deodorizing performance and antibacterial property imparted to the water absorbent resin described above, improvement of moisture absorption fluidity (anti-caking improvement) is a major issue. That is, there is a problem in that the water-absorbent resin loses fluidity as a powder when it absorbs moisture and blocking occurs. Patent Document 12 also discloses a technique of adding various additives in order to deal with this problem.

  However, the deodorizing performance in the above-described methods reported heretofore has not been sufficient, and the deodorizing performance to be exhibited in actual use has not reached a satisfactory level. Moreover, if the absorption performance is sacrificed in order to exhibit high deodorization performance, the original purpose of the water-absorbing resin of absorbing body fluids such as urine and blood cannot be achieved.

  Therefore, it is important that the deodorizing performance is exhibited and the absorption performance is sufficiently satisfactory.

Moreover, when an additive is included in the water-absorbent resin for improving the deodorizing performance and moisture absorption fluidity, separation or dropping may occur if the additive is powder. When the additive is separated or dropped, dust is generated and sufficient performance as an additive cannot be exhibited.
JP-A-60-158861 Japanese Patent Laid-Open No. 11-244103 JP-A-8-176338 JP-A-10-147724 Japanese Patent Laid-Open No. 10-298442 Japanese Patent Laid-Open No. 11-116829 JP-A-11-49971 Japanese Patent Laid-Open No. 11-148023 JP-A-2-41155 JP-A-63-135501 Japanese Unexamined Patent Publication No. 64-5546 International Publication No. 00/01479 Pamphlet

  The object of the present invention is that the additive does not fall off from the water-absorbent resin, has excellent fluidity of the powder after the water-absorbent resin or water-absorbent resin composition has absorbed moisture, and is a sulfur compound such as hydrogen sulfide or mercaptans. It is intended to provide a water-absorbent resin composition, an absorbent body, and an absorbent article that have a deodorizing performance that can sufficiently remove malodors derived from the above, and that are excellent in absorption performance. That is, an object of the present invention is to provide a water-absorbent resin composition, an absorbent body, and an absorbent article that have a low additive separation rate, excellent moisture absorption fluidity and deodorization performance, and excellent absorption performance. is there. Another object of the present invention is to provide a method for producing a water-absorbent resin composition having such characteristics.

  The present inventor has intensively studied to solve the above problems. As a result, attention was paid to the fact that the combination of the water-absorbent resin and zinc is effective in developing the deodorizing performance. And, as a result of examining in detail the conditions for improving the deodorization performance and exhibiting excellent absorption performance and excellent hygroscopic fluidity, water-absorbent resin having predetermined absorption performance and zinc and silicon, or zinc and aluminum It has been found that the above-mentioned problems can be solved by combining with a composite hydrous oxide containing a selenium at a predetermined ratio.

That is, the present invention relates to a water-absorbing resin obtained by polymerizing and crosslinking a monomer component mainly composed of acrylic acid and / or a salt thereof, and a composite hydrous oxide containing zinc and silicon, or zinc and aluminum. a water-absorbing resin composition containing the goods, the hydrous composite oxide contains zinc as a main component of the metal, the mass ratio of 70 / 30-95 between the content and the silicon or the aluminum content of the zinc / 5 , and the content of the composite hydrous oxide is 0.001 to 5 parts by mass with respect to 100 parts by mass of the water absorbent resin, and a 0.90 mass% sodium chloride aqueous solution of the water absorbent resin composition Is a water absorbent resin composition having a water absorption capacity under load at 1.9 kPa (60 minutes value) of 20 g / g or more.

  Moreover, this invention is an absorber for sanitary materials containing the said water absorbing resin composition and a hydrophilic fiber.

The present invention also includes a water-absorbent resin obtained by polymerizing and crosslinking a monomer component mainly composed of acrylic acid and / or a salt thereof , a hydrophilic fiber, and zinc and silicon, or zinc and aluminum. And the composite hydrous oxide contains zinc as a main component of the metal, and the mass ratio of the zinc content to the silicon or aluminum content is 70 / 30 to 95/5, the content of the hydrous composite oxide with respect to 100 parts by mass of the water absorbent resin is 0.001 to 5 parts by weight, the 0.90 mass% of the water-absorbing resin of sodium chloride A sanitary material absorbent body characterized by having a water absorption capacity under pressure of 1.9 kPa (60 minutes value) with respect to an aqueous solution of 20 g / g or more.

  Moreover, this invention is an absorptive article provided with the said absorber, the surface sheet which has liquid permeability, and the back sheet | seat which shows liquid impermeability.

The present invention also provides a water absorption capacity under pressure of 1.9 kPa with respect to a 0.90 mass% aqueous sodium chloride solution (60 minutes) by polymerizing and crosslinking a monomer component mainly composed of acrylic acid and / or a salt thereof. Value) of 20 g / g or more of the water-absorbent resin, and in the water-absorbent resin, zinc having a mass ratio of zinc content to silicon or aluminum content of 70/30 to 95/5 and And a step of adding 0.001 to 5 parts by mass of a mixed water- containing oxide containing silicon or zinc and aluminum to the water-absorbent resin and 100 parts by mass and mixing the same . It is a manufacturing method of a resin composition.

  The water-absorbent resin composition, the absorbent body, and the absorbent article of the present invention have a low separation rate of additives from the water-absorbent resin, are excellent in hygroscopic fluidity and deodorization performance, and are excellent in gel strength and absorption performance. Moreover, the water-absorbent resin composition having such characteristics can be obtained by the production method of the present invention.

(1) Water absorbent resin (A)
The water-absorbent resin (A) used in the present invention is a water-swellable and water-insoluble crosslinked polymer that can form a hydrogel. Water swellability refers to the ability to absorb a large amount of water in ion exchange water at least 5 times its own weight, preferably 50 to 1000 times. Water-insoluble means that the content of the uncrosslinked water-soluble component (water-soluble polymer) in the water-absorbent resin is preferably 50% by mass or less (lower limit is 0% by mass), more preferably 25% by mass. Hereinafter, it is more preferably 20% by mass or less, particularly preferably 15% by mass or less, and most preferably 10% by mass or less. In addition, the measuring method of this water-soluble component is described in EDANA RECOMMENDED TEST METHODS 470, 1-99 EXTRATABLES of EUROPEAN DISPOSABLES AND NONWOVENS ASSOCIATION.

  In the description of the present invention, when the content ratio of the water absorbent resin standard is described, it is based on the solid content of the water absorbent resin. For example, it is calculated as a content ratio when 1 g of water-absorbent resin is used and dried at 180 ° C. for 3 hours to make the water content 10% by mass or less.

  In the present invention, as the water absorbent resin (A), a water absorbent resin having a crosslinked structure obtained by polymerizing an unsaturated monomer containing an acid group and / or a salt thereof from the viewpoint of deodorizing performance and absorption performance. Is used.

  Examples of the water-absorbent resin (A) include polyacrylic acid partial neutralized polymer, starch-acrylonitrile graft polymer hydrolyzate, starch-acrylic acid graft polymer, saponified vinyl acetate-acrylic acid ester copolymer. 1 type, or 2 or more types, such as a hydrolyzate of an acrylonitrile copolymer or an acrylamide copolymer or a crosslinked product thereof, a carboxyl group-containing crosslinked polyvinyl alcohol modified product, a crosslinked isobutylene-maleic anhydride copolymer, and the like. Preferably, a partially neutralized polyacrylic acid polymer obtained by polymerizing and crosslinking a monomer component mainly composed of acrylic acid and / or a salt thereof (neutralized product) as the water absorbent resin (A). Is used.

  The water absorbent resin (A) has an acid group and / or a salt thereof. Preferably, the water-absorbing resin (A) is obtained by polymerizing a monomer component containing an acid group-containing unsaturated monomer as a main component. The acid group-containing unsaturated monomer includes a monomer that becomes an acid group by hydrolysis after polymerization, such as acrylonitrile, but preferably contains an acid group that contains an acid group at the time of polymerization. Unsaturated monomers are used.

  In the present invention, it is preferable that acrylic monomer and / or a salt thereof be a main component as a monomer component.

  When acrylic acid and / or a salt thereof is a main component as a monomer component, other monomers may be used in combination. The monomer that can be used in combination is not particularly limited as long as the effects of the present invention can be exhibited by the combined use. For example, methacrylic acid, maleic acid, maleic anhydride, fumaric acid, crotonic acid, itaconic acid, vinyl sulfone Acid, 2- (meth) acrylamide-2-methylpropanesulfonic acid, (meth) acryloxyalkanesulfonic acid and its alkali metal salt, ammonium salt, N-vinyl-2-pyrrolidone, N-vinylacetamide, (meth) acrylamide , N-isopropyl (meth) acrylamide, N, N-dimethyl (meth) acrylamide, 2-hydroxyethyl (meth) acrylate, methoxypolyethylene glycol (meth) acrylate, polyethylene glycol (meth) acrylate, isobutylene, lauryl (meth) acrylic Over water-soluble or hydrophobic unsaturated monomers such as bets and the like.

  When a monomer other than acrylic acid and / or its salt is used, the ratio of the monomer other than acrylic acid and / or its salt is the total amount of acrylic acid and / or its salt used as the main component. On the other hand, Preferably it is 0-30 mol%, More preferably, it is 0-10 mol%. By using at such a ratio, the absorption performance of the obtained water-absorbent resin is further improved. Further, the water absorbent resin can be obtained at a lower cost. In addition, the effects of the present invention can be sufficiently exhibited.

  The water absorbent resin (A) has a crosslinked structure. The crosslinked structure may be a self-crosslinking type that does not use a crosslinking agent. Preferably, the water absorbent resin (A) is a crosslinked structure formed by copolymerization or reaction using an internal crosslinking agent having two or more polymerizable unsaturated groups or two or more reactive groups in one molecule. Have

  Specific examples of the internal crosslinking agent include, for example, N, N′-methylenebis (meth) acrylamide, (poly) ethylene glycol di (meth) acrylate, (poly) propylene glycol di (meth) acrylate, trimethylolpropane tri (meta) ) Acrylate, glycerin tri (meth) acrylate, glycerin acrylate methacrylate, ethylene oxide modified trimethylolpropane tri (meth) acrylate, pentaerythritol hexa (meth) acrylate, triallyl cyanurate, triallyl isocyanurate, triallyl phosphate, triallylamine , Poly (meth) allyloxyalkane, (poly) ethylene glycol diglycidyl ether, glycerol diglycidyl ether, ethylene glycol, polyethylene Recall, propylene glycol, glycerol, pentaerythritol, ethylenediamine, ethylene carbonate, propylene carbonate, polyethylenimine, and glycidyl (meth) acrylate.

  An internal crosslinking agent may be used independently and may be used in mixture of 2 or more types suitably. The internal cross-linking agent may be added all at once to the reaction system, or may be added in divided portions. When using an internal cross-linking agent, it is preferable to use a compound having two or more polymerizable unsaturated groups during polymerization in order to sufficiently exhibit the effects of the present invention.

  The amount of the internal crosslinking agent used is preferably 0.001 to 2 mol%, more preferably 0.005 to 0.5 mol%, and still more preferably 0.01 to 2 mol% with respect to the monomer component excluding the crosslinking agent. The amount is 0.2 mol%, particularly preferably 0.03 to 0.15 mol%. When the amount of the internal crosslinking agent used is less than 0.001 mol% or more than 2 mol%, the obtained water absorbent resin may not be able to exhibit sufficient absorption characteristics. Moreover, there exists a possibility that the effect of this invention may not fully express.

  When a crosslinked structure is introduced into the polymer using an internal crosslinking agent, the internal crosslinking agent may be added to the reaction system before, during, after, or after the polymerization of the monomer component.

  The neutralization rate of the water-absorbent resin (A) that can be used in the present invention is not particularly limited, but is preferably 30 to 90 mol%, more preferably 30 to 75, in order to fully exhibit the effects of the present invention. The mol%, more preferably 30 to 70 mol%, still more preferably 50 mol% or more and less than 70 mol%.

  A method for polymerizing the monomer component to obtain the water-absorbent resin (A) is not particularly limited, and examples thereof include aqueous solution polymerization, reverse phase suspension polymerization, bulk polymerization, and precipitation polymerization. From the viewpoints of performance, ease of control of polymerization, and absorption characteristics of the swollen gel, aqueous solution polymerization or reverse phase suspension polymerization in an aqueous solution containing a monomer component is preferable.

  The concentration of the monomer component in the aqueous solution containing the monomer component (hereinafter also referred to as “monomer aqueous solution”) depends on the temperature of the aqueous solution and the type of the monomer component, and is not particularly limited. The concentration of the monomer component is preferably in the range of 10 to 70% by mass, and more preferably in the range of 20 to 60% by mass. When performing aqueous solution polymerization, you may use together solvents other than water as needed. The kind of solvent used in combination is not particularly limited.

  Reverse phase suspension polymerization is a polymerization method in which an aqueous monomer solution is suspended in a hydrophobic organic solvent. Reverse phase suspension polymerization is described, for example, in US Pat. No. 4,093,776, US Pat. No. 4,367,323, US Pat. No. 4,446,261, US Pat. No. 4,683,274, US Pat. No. 5,244,735. The aqueous solution polymerization is a method of polymerizing an aqueous monomer solution without using a dispersion solvent. Aqueous polymerization is described, for example, in U.S. Pat. No. 4,625,001, U.S. Pat. No. 4,873,299, U.S. Pat.No. 4,286,082, U.S. Pat. No. 4,973,632, U.S. Pat. No. 4,985,518, U.S. Pat. No. 5,124,416, U.S. Pat. No. 5,264,495, U.S. Pat. No. 5,145,906, U.S. Pat. No. 5,380,808, and European patents such as European Patent No. 081636, European Patent No. 095586, and European Patent No. 0922717. Monomer components and initiators exemplified in these polymerization methods can also be applied to the present invention.

  When starting the polymerization, for example, radical polymerization of potassium persulfate, ammonium persulfate, sodium persulfate, t-butyl hydroperoxide, hydrogen peroxide, 2,2′-azobis (2-amidinopropane) dihydrochloride, etc. An initiator or a photopolymerization initiator such as 2-hydroxy-2-methyl-1-phenyl-propan-1-one can be used. The amount of the polymerization initiator used is preferably from 0.001 to 2 mol%, more preferably to all monomer components, considering the physical properties of the resulting water-absorbent resin. 0.01 to 0.1 mol%.

  By carrying out the polymerization, a hydrogel crosslinked polymer is usually obtained. This water-containing gel-like cross-linked polymer is subdivided as necessary and further dried, and preferably pulverized before and / or after drying to obtain a water-absorbing resin.

  Drying is preferably performed in a temperature range of 60 ° C to 250 ° C, more preferably in a temperature range of 100 ° C to 220 ° C, and still more preferably in a temperature range of 120 ° C to 200 ° C. The drying time depends on the surface area of the polymer, the moisture content, the type of the dryer, etc., and is selected so as to achieve the desired moisture content.

  The water content of the water-absorbent resin (A) is not particularly limited, but is preferably a powder that exhibits fluidity even at room temperature in order to fully exhibit the effects of the present invention. The water content of the water absorbent resin (A) is preferably 0.2 to 30% by mass, more preferably 0.3 to 15% by mass, still more preferably 0.5 to 10% by mass, preferably in a powder state. is there. The water content of the water absorbent resin is defined as the amount of water contained in the water absorbent resin. For example, the weight loss can be measured when 1 g of water absorbent resin is used and dried at 180 ° C. for 3 hours.

  Since it is difficult to make the water content of the water absorbent resin zero, for example, a powdery water absorbent resin containing a small amount of water of about 0.5 to 10% by mass may be used. Moreover, when measuring the physical property prescribed | regulated in this specification about the commercially available water-absorbing resin and water-absorbing resin composition, and the water-absorbing resin and water-absorbing resin composition in a diaper, for example, by drying, the water content is reduced. The physical properties are measured by adjusting to 10% by mass or less, preferably 5 ± 2% by mass. The drying conditions for adjusting the moisture content are not particularly limited as long as the water-absorbing resin and the water-absorbing resin composition are not decomposed or modified, but drying under reduced pressure at 70 ° C. or lower is preferable.

  The particle shape of the water absorbent resin (A) is not particularly limited, and examples thereof include a spherical shape, a crushed shape, and an indefinite shape. The thing of the irregular-shaped crush form obtained through the grinding | pulverization process is preferable. In addition, the bulk specific gravity of the water absorbent resin (A) defined by JIS K-3362 is preferably within a range of 0.40 to 0.80 g / ml, in order to sufficiently exhibit the effects of the present invention. Preferably it is in the range of 0.50 to 0.75 g / ml, more preferably in the range of 0.60 to 0.73 g / ml.

  The water absorbent resin (A) that can be used in the present invention is preferably further subjected to surface cross-linking (secondary cross-linking).

  There are various crosslinking agents (surface crosslinking agents) for performing surface crosslinking, and there is no particular limitation. From the viewpoint of improving the properties of the water-absorbing resin obtained, polyhydric alcohol compounds, epoxy compounds, polyvalent amine compounds or condensates thereof with haloepoxy compounds, oxazoline compounds, mono-, di-, or polyoxazolidinone compounds, polyvalent metals Salts, alkylene carbonate compounds and the like are preferable.

  The surface cross-linking agent is not particularly limited, and for example, surface cross-linking agents exemplified in US Pat. No. 6,228,930, US Pat. No. 6,071,976, US Pat. No. 6,254,990 can be used. Specific examples of the surface crosslinking agent include mono-, di-, tri-, tetra- or polyethylene glycol, monopropylene glycol, 1,3-propanediol, dipropylene glycol, 2,3,4-trimethyl-1,3-pentanediol, Polypropylene glycol, glycerin, polyglycerin, 2-butene-1,4-diol, 1,4-butanediol, 1,3-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,2- Polyhydric alcohol compounds such as cyclohexanedimethanol; Epoxy compounds such as ethylene glycol diglycidyl ether and glycidol; ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, polyethyleneimine, poly Polyamine compounds such as midpolyamine; haloepoxy compounds such as epichlorohydrin, epibromohydrin, α-methylepichlorohydrin; condensates of the polyamine compounds with the haloepoxy compounds; 2-oxazolidinones, etc. Oxazolidinone compounds; alkylene carbonate compounds such as ethylene carbonate and the like. Only 1 type of these may be used and 2 or more types may be used together. In order to fully exhibit the effects of the present invention, it is preferable to use a polyhydric alcohol as the surface cross-linking agent. As a polyhydric alcohol, a C2-C10 thing is preferable and a C3-C8 thing is more preferable.

  The amount of the surface cross-linking agent used is preferably in the range of 0.001 to 10% by mass, more preferably 0.001% by mass with respect to the water-absorbent resin (A), although it depends on the compounds used and combinations thereof. It is in the range of 01 to 5% by mass.

  When performing surface crosslinking, it is preferable to use water. The amount of water used depends on the water content of the water-absorbing resin (A) used, but is preferably in the range of 0.5 to 20% by mass with respect to the water-absorbing resin (A). Preferably it exists in the range of 0.5-10 mass%. In addition to water, a hydrophilic organic solvent may be used. When using a hydrophilic organic solvent, the amount of use thereof is preferably in the range of 0 to 10% by mass, more preferably in the range of 0 to 5% by mass, even more preferably with respect to the water absorbent resin (A). Is in the range of 0 to 3% by weight.

  In the case of performing the surface crosslinking, a method in which water and / or a hydrophilic organic solvent and a surface crosslinking agent are mixed in advance, and then the aqueous solution is sprayed or dropped and mixed with the water absorbent resin is preferable. More preferably, a spraying method is used. The average particle size of the sprayed droplets is preferably in the range of 0.1 to 300 μm, more preferably 0.1 to 200 μm. In the case of mixing water and / or a hydrophilic organic solvent and a surface crosslinking agent, a water-insoluble fine particle powder or a surfactant may be allowed to coexist within a range not impeding the effects of the present invention.

  The water-absorbing resin after mixing the surface cross-linking agent is preferably heat-treated. The heating temperature measured as the heat medium temperature or the material temperature is preferably in the range of 100 to 250 ° C, more preferably in the range of 150 to 250 ° C. The heating time is preferably in the range of 1 minute to 2 hours. Preferable examples of the combination of the heating temperature and the heating time are 0.1 to 1.5 hours at 180 ° C. and 0.1 to 1 hour at 200 ° C.

  The surface-absorbed water-absorbing resin produced by the above procedure is preferably adjusted to a specific particle size so that the effects of the present invention can be fully exerted. The particle size may be adjusted before or after the surface treatment. Examples of the means for adjusting the particle size include pulverization, classification, granulation and the like, and these may be appropriately controlled. Since the water-absorbent resin of the present invention has an acid group such as a carboxyl group and / or a salt thereof, for example, a basic malodorous substance such as ammonia can be effectively neutralized. The surface area of the water-absorbent resin is larger as the particle size is smaller, and the larger the surface area, the more effective it is to neutralize basic malodorous substances, but in actual use such as urine gelling agents such as disposable diapers. Was found to be superior when controlled to a specific particle size.

  Although the mechanism of the manifestation of the effect by adjusting to a specific particle size is not clear, it is presumed that, for example, the gel state of the water-absorbent resin has an influence. When the particle diameter is too small, the water absorption rate is too high, so that the gel block is generated, and it is considered that the liquid containing malodorous components hardly reaches the used water absorbent resin or the water absorbent resin composition containing the same. Moreover, when the particle diameter is too large, the water absorption rate is slow, and therefore, the malodorous component is volatilized from the liquid containing the malodorous component.

  Specifically, preferably, particles of 150 μm or more and less than 850 μm are 90% by mass or more (upper limit of 100% by mass) of the whole, and particles of 300 μm or more are 60% by mass or more of the whole (upper limit of 100% by mass). is there. The larger the number of particles of 150 μm or more and less than 850 μm, the better. That is, more preferably 95 to 100% by mass, and still more preferably 98 to 100% by mass. The particle size of 300 μm or more is more preferably 65% by mass or more, further preferably 70% by mass or more, and particularly preferably 75% by mass or more. The upper limit of this amount is not particularly high, and it is preferably as high as possible, that is, 100% by mass. However, there is a case where a significant cost increase is involved in achieving 100% by mass, and the upper limit may be 99% by mass or less.

  The mass average particle diameter of the water absorbent resin (A) is preferably 200 to 700 μm, more preferably 300 to 600 μm, and particularly preferably 400 to 500 μm. The mass average particle diameter is also applied to a water absorbent resin composition described later, and the mass average particle diameter of the water absorbent resin (A) or the water absorbent resin composition may be adjusted by granulation, if necessary.

  The water-absorbent resin (A) has an absorption capacity without load with respect to a 0.90% by mass sodium chloride aqueous solution, preferably 26 g / g or more, more preferably 28 g / g or more, and still more preferably 30 g / g or more. Especially preferably, it is 32 g / g or more. If the absorption capacity under no pressure with respect to the 0.90 mass% sodium chloride aqueous solution is smaller than 26 g / g, the effect of the present invention may not be sufficiently exhibited. The higher the absorption capacity under no pressure, the better. However, to increase the absorption capacity under no pressure to a certain level or more, there is a risk of causing a significant increase in cost and a decrease in other physical properties (for example, water-soluble components). In that case, the absorption capacity under no pressure may be 100 g / g or less, preferably 90 g / g or less.

  The water absorbent resin (A) has an absorption capacity under pressure of 1.9 kPa with respect to a 0.90 mass% sodium chloride aqueous solution, preferably 20 g / g or more, more preferably 22 g / g or more, and still more preferably 24 g / g. g or more, particularly preferably 26 g / g or more. When the absorption capacity under pressure at 1.9 kPa with respect to the 0.90 mass% sodium chloride aqueous solution is smaller than 20 g / g, the effect of the present invention may not be sufficiently exhibited. The higher the absorption capacity under pressure, the better. However, in order to increase the absorption capacity under pressure to a certain level or more, there is a risk of causing a significant increase in cost and other physical properties. In that case, the absorption capacity under pressure is 60 g. / G or less, preferably 50 g / g or less.

  In order to maximize the effects of the present invention, the absorbency against pressure of 0.90 mass% sodium chloride aqueous solution is 26 g / g or more and 1.9 kPa relative to 0.90 mass% sodium chloride aqueous solution. It is particularly preferable to use a water-absorbent resin having an absorption capacity under pressure of 20 g / g or more.

(2) Composite hydrous oxide (B)
The composite hydrous oxide (B) is a hydrous oxide containing zinc as a main component and containing (b1) zinc and silicon or (b2) zinc and aluminum based on the total mass of the metal component. The ratio of the zinc element which is a main component in a metal component is 50-99.9 mass% in all the metal components, Preferably it is the range of 60-95 mass%, More preferably, it is the range of 70-95 mass%. The “hydrated oxide” is also referred to as a hydrated oxide, and refers to a hydrated metal oxide containing a so-called hydroxide. In the case of (b1), the composite hydrous oxide (B) is a hydrous oxide having at least part of a —Zn—O—Si— bond with respect to zinc (Zn) and silicon (Si). It is different from a simple mixture of an oxide and a hydrous oxide of Si. Similarly, in the case of (b2), with respect to zinc (Zn) and aluminum (Al), it is a hydrous oxide having at least a part of a bond of —Zn—O—Al—, and the hydrous oxide of Zn and the hydrous oxide of Al. It differs from simple mixtures with oxides. That is, the composite hydrous oxide (B) is a composite hydrous oxide containing (b1) zinc and silicon, or (b2) zinc and aluminum. For example, zeolite, a simple mixture of zinc oxide and silicon dioxide, zinc oxide A simple mixture of aluminum oxide and aluminum oxide is not included in the composite hydrous oxide (B). These compounds tend to fall off from the surface of the water absorbent resin. Moreover, the effect of this invention cannot be exhibited.

  (B1) When the composite hydrous oxide (B) containing zinc and silicon or (b2) zinc and aluminum is present on the surface of the water-absorbent resin, the water-absorbent resin absorbs water even if it absorbs the aqueous liquid and gels. It is difficult to separate or drop off from the surface of the conductive resin. This is presumably because (b1) zinc and silicon or (b2) zinc and aluminum-containing composite hydrous oxide in the present invention has a high content ratio of zinc in the metal component. For example, in the case of titanium and aluminum, or a composite hydrous oxide containing titanium and silicon, as exemplified in a comparative example to be described later, the water absorbent resin absorbs the aqueous liquid and gels. Easy to separate or drop from the surface. In the implementation of diapers and the like, in order to enhance the deodorizing effect, it is preferable that the separation or removal from the surface of the water absorbent resin is less.

  Furthermore, the composite hydrous oxide (B) containing (b1) zinc and silicon, or (b2) zinc and aluminum is more effective than using a simple mixture of oxides of the respective metal elements. Since different metals of zinc and silicon, or zinc and aluminum are present in close proximity to each other, the separation from the swollen gel is reduced and the deodorizing effect is increased compared to a simple mixture of oxides of each metal element. Conceivable. In addition, when the water-absorbent resin powder and the powdered composite hydrous oxide are mixed to obtain the water-absorbent resin composition of the present invention, the composite hydrous oxide adheres uniformly to the surface of the water-absorbent resin and is simple. Separation as seen in the mixture is significantly suppressed.

  The composite hydrous oxide (B) may contain other metal components as long as it contains (b1) zinc and silicon or (b2) zinc and aluminum in the mass ratio of the present invention described later. However, from the viewpoint of further improvement of the effect and price, it is preferable that there are only (b1) two types of zinc and silicon, or (b2) only two types of zinc and aluminum. When there are three or more metal components, the content of the third metal component in all the metal components is preferably 5% by mass or less, more preferably 3% by mass or less, and further preferably 1% by mass or less. Moreover, if zinc is an essential component in the metal component, it may contain magnesium, calcium, silver, copper, nickel, iron, manganese, titanium, barium, and zirconium.

  (B1) The mass ratio of the zinc content and the silicon content in the composite hydrous oxide (B) containing zinc and silicon is preferably 50/50 to 99/1, more preferably 60/40 to 99/1, more preferably 65/35 to 95/5, particularly preferably 70/30 to 95/5. If the mass ratio is out of the above range, the effects of the present invention may not be sufficiently exhibited.

  (B2) The mass ratio of the zinc content and the aluminum content in the composite hydrous oxide (B) containing zinc and aluminum is preferably 50/50 to 99/1, more preferably 60/40 to 99/1, more preferably 65/35 to 95/5, particularly preferably 70/30 to 95/5. If the mass ratio is out of the above range, the effects of the present invention may not be sufficiently exhibited.

  If the mass ratio of the metal component content in the composite hydrous oxide (B) containing (b1) zinc and silicon, or (b2) zinc and aluminum is not known, use a technique such as fluorescent X-ray analysis or elemental analysis. It can be calculated.

  The composite hydrous oxide (B) containing (b1) zinc and silicon, or (b2) zinc and aluminum can contain oxygen as a main component related to the total mass of the nonmetallic component. Other nonmetallic components include hydrogen and the like, and may contain trace amounts of impurity components such as reaction byproducts. The proportion of oxygen element as the main component in the non-metallic component is usually 50% to 99.9% by mass, preferably 60 to 95% by mass, and more preferably 70 to 95% by mass in the total metal element component. It is a range.

  The content of (b1) zinc and silicon, or (b2) the composite hydrous oxide containing zinc and aluminum (B) with respect to 100 parts by mass of the water absorbent resin (A) is preferably 0.001 to 5 parts by mass, more preferably Is 0.05-4 parts by mass, more preferably 0.1-3 parts by mass. If the content is less than 0.001 part by mass, the deodorizing performance may be insufficient, and if it exceeds 5 parts by mass, the inherent absorption performance of the water absorbent resin may be reduced.

  The particle diameter of the composite hydrous oxide (B) containing (b1) zinc and silicon or (b2) zinc and aluminum is preferably in the range of 0.001 to 1000 μm, more preferably 0.01 to 600 μm. Within range. The mass average particle diameter is preferably 500 μm or less, more preferably 300 μm or less.

  The composite hydrous oxide (B) containing (b1) zinc and silicon or (b2) zinc and aluminum is preferably obtained by a specific method. The composite hydrous oxide (B) containing (b1) zinc and silicon or (b2) zinc and aluminum can be obtained by various methods such as a liquid phase method, a gas phase method, a solid phase method, etc. From the viewpoint of production cost, it is preferably prepared by a liquid phase method, more preferably by a coprecipitation method. In general, the “coprecipitation method” means a technique for simultaneously precipitating two or more ions. In the present invention, two or more ions are obtained by coprecipitation, specifically by changing the concentration, pH, temperature, solvent, etc. of the mixed solution containing two or more ions. Are co-precipitated simultaneously to obtain a co-precipitate having a predetermined composition. And a desired compound is obtained by drying after isolate | separating a coprecipitate. The coprecipitation method is different from a method in which a precipitate is separately generated for each metal, and the powder obtained by separating the precipitate and then drying is simply mixed.

  In the method of obtaining the composite hydrous oxide (B) containing (b1) zinc and silicon or (b2) zinc and aluminum by the coprecipitation method, the method for causing the coprecipitation is not particularly limited, and various methods are available. Can be mentioned. For example, a method of adding ammonia water or urea to a mixed solution containing a zinc salt and a silicon salt, or a mixed solution containing a zinc salt and an aluminum salt, and heating as necessary; zinc salt and aluminum Examples include a method of adding aqueous ammonia or urea to a mixed solution containing the salt and heating as necessary.

  Examples of the zinc salt, silicon salt, and aluminum salt are not particularly limited. Examples thereof include sulfates, oxysulfates, chlorides, oxychlorides, nitrates, oxynitrates, carboxylates and the like of zinc, silicon, and aluminum. Of these, sulfate, oxysulfate, chloride, and oxychloride are preferably used.

  As a method of causing precipitation, in addition to using salt as a raw material, a method of causing coprecipitation from a mixed solution containing zinc alkoxide and silicon alkoxide by simultaneous hydrolysis; containing zinc alkoxide and aluminum alkoxide A method of causing coprecipitation from the mixed solution by simultaneous hydrolysis is also preferably used. Examples of zinc alkoxide, silicon alkoxide, and aluminum alkoxide are not particularly limited, and examples include zinc, silicon, and aluminum methoxide, ethoxide, propoxide, butoxide, and the like.

  Precipitation conditions for coprecipitation are important because they affect the precipitation rate, the shape of the coprecipitate, etc., but the starting material, the composition of the mixed solution, the concentration, the type of the precipitated substance, and the precipitation are caused. Since it differs depending on the method, etc., precipitation conditions corresponding to each method are adopted.

  The coprecipitate produced by the coprecipitation is optionally filtered, washed and dried. At this time, the drying temperature is preferably a relatively low temperature, for example, 100 ° C. to 200 ° C. is preferable. If the drying temperature exceeds 600 ° C, the deodorizing performance may be reduced.

(3) Plant component (C)
The plant component (C) preferably contains at least one compound selected from polyphenols, flavones and the like, and caffeine in excess of 0 and 100% by mass or less based on the total mass of the plant component (C). . Preferably, at least one compound selected from tannin, tannic acid, pentaploid, gallic acid and gallic acid is used as the plant component (C).

  Examples of the plant containing the plant component (C) include camellia, hisakaki, mokkok, etc. for camellia plants, and rice, sasa, bamboo, corn, wheat, etc. for gramineous plants. Plants include coffee.

  Examples of the form of the plant component (C) include extracts extracted from plants (essential oil), plants themselves (plant powder), plant meals and extracted meals produced as by-products in the manufacturing process in the plant processing industry and food processing industry. There is no particular limitation.

  Although the usage-amount of a plant component (C) changes also with the target deodorizing function, Preferably it exists in the range of 0.001-10 mass parts with respect to 100 mass parts of water absorbing resin (A), and more. Preferably it exists in the range of 0.01-5 mass parts. When the amount is less than 0.001 part by mass, a sufficient effect may not be obtained. When the amount exceeds 10 parts by mass, the effect corresponding to the amount added may not be obtained.

  The plant component (C) itself is a powder and / or a powder carrying an extract (essential oil) containing a plant component (C) extracted from a plant and / or extracted from a plant. In the case of a powder in which the extract (essential oil) containing the plant component (C) is carried on a fine powder (B) made of an aggregate of metal hydrated oxide containing zinc and silicon or zinc and aluminum, 90% by mass The particle diameter of the above particles is preferably in the range of 0.001 to 1000 μm, more preferably in the range of 0.01 to 600 μm. The mass average particle diameter is preferably 500 μm or less, more preferably 300 μm or less. When the mass average particle diameter is larger than 500 μm, when it comes into contact with urine or the like, the action of the active ingredient contained in the plant component (C) becomes insufficient, and there is a possibility that stable deodorizing performance cannot be imparted. Moreover, since the one where the mass average particle diameter of the powder containing the plant component (C) is smaller than the mass average particle diameter of the water absorbent resin can provide excellent deodorizing performance and stability, it is preferable.

  The plant component (C) is preferably a liquid and / or an aqueous solution at room temperature.

(4) Water-absorbent resin composition The water-absorbent resin composition of the present invention comprises the above-mentioned water-absorbent resin (A) and the aforementioned (b1) zinc and silicon, or (b2) a composite hydrous oxide containing zinc and aluminum ( B). That is, the water absorbent resin composition of the present invention comprises a water absorbent resin (A) obtained by polymerizing an unsaturated monomer containing an acid group and / or a salt thereof, and (b1) zinc and silicon, or ( b2) A water-absorbent resin composition comprising a composite hydrous oxide (B) containing zinc and aluminum.

  (B1) Zinc and silicon in water absorbent resin composition, or (b2) Mass ratio of zinc and silicon content in composite hydrous oxide (B) containing zinc and aluminum, or zinc and aluminum content The mass ratio is preferably 50/50 to 99/1, more preferably 60/40 to 99/1, still more preferably 65/35 to 90/10, and particularly preferably 70/30 to 90/10. is there. In the case of using a composite hydrous oxide containing three components of zinc, silicon and aluminum, it is preferable that at least one of the above-described mass ratios is satisfied, and it is preferable that both of the above-described mass ratios are satisfied. In the composite hydrous oxide (B) containing zinc and silicon or zinc and aluminum, when the mass ratio of zinc to silicon or the mass ratio of zinc to aluminum is 1/99 to 49/51, hydrogen sulfide or Deodorant performance that can sufficiently remove malodor derived from sulfur compounds such as mercaptans cannot be exhibited.

  The method for producing the water absorbent resin composition is not particularly limited, but preferably, a polymerization step of polymerizing an unsaturated monomer containing an acid group to obtain a water absorbent resin, the water absorbent resin, and zinc And a mixing step with silicon, or a composite hydrous oxide containing zinc and aluminum. Thereby, the water absorption resin composition whose water absorption capacity | capacitance under pressure in 1.9 kPa (60 minute value) with respect to 0.90 mass% sodium chloride aqueous solution is 20 g / g or more is obtained.

  The water-absorbing resin (A) obtained through the polymerization step means a water-absorbing resin that has been subjected to the polymerization step. For example, a water-absorbing resin that has not been surface-crosslinked, obtained by polymerization, or further surface-crosslinked after polymerization. Water-absorbing resin and the like.

  The polymerization process for obtaining the water-absorbent resin (A) by polymerizing a monomer component containing an acid group-containing unsaturated monomer as a main component is as described above.

  The water-absorbent resin (A) obtained through the polymerization step has a non-pressure absorption capacity of 0.90% by mass sodium chloride aqueous solution, preferably 26 g / g or more, more preferably 28 g / g or more, More preferably, it is 30 g / g or more, Most preferably, it is 32 g / g or more. If the absorbency against pressure of 0.90 mass% sodium chloride aqueous solution is less than 26 g / g, the effects of the present invention may not be sufficiently exhibited. The higher the absorption capacity under no pressure, the better. However, to increase the absorption capacity under no pressure to a certain level or more, there is a risk of causing a significant increase in cost and a decrease in other physical properties (for example, water-soluble components). In that case, the absorption capacity under no pressure may be 100 g / g or less, preferably 90 g / g or less.

  The water-absorbent resin (A) obtained through the polymerization step has an absorption capacity under pressure at 1.9 kPa with respect to a 0.90% by mass sodium chloride aqueous solution, preferably 20 g / g or more, more preferably 24 g / g. Or more, more preferably 26 g / g or more, and particularly preferably 28 g / g or more. When the absorption capacity under pressure at 1.9 kPa with respect to the 0.90 mass% sodium chloride aqueous solution is smaller than 20 g / g, the effect of the present invention may not be sufficiently exhibited. The higher the absorption capacity under pressure, the better. However, in order to increase the absorption capacity under pressure to a certain level or more, there is a risk of causing a significant increase in cost and a decrease in other physical properties. May be 60 g / g or less, preferably 50 g / g or less.

  In order to maximize the effects of the present invention, the water-absorbent resin (A) obtained through the polymerization step has an absorption capacity of 26 g / g or more under no pressure with respect to a 0.90 mass% sodium chloride aqueous solution, And it is especially preferable that the absorption capacity | capacitance under pressure in 1.9 kPa with respect to 0.90 mass% sodium chloride aqueous solution is 20 g / g or more.

  The composite hydrous oxide (B) containing (b1) zinc and silicon, or (b2) zinc and aluminum is preferably added to the water absorbent resin (A) obtained through the polymerization step. By adding the composite hydrous oxide (B) to the water absorbent resin (A) obtained through the polymerization step, (b1) composite hydrous oxide (B) containing zinc and silicon, or (b2) zinc and aluminum Is present more on the surface of the water-absorbent resin (A), and the effects of the present invention are more fully exhibited. The form of adding the composite hydrous oxide (B) to the water-absorbing resin obtained through the polymerization step is, for example, a form added after polymerization and drying, a form added during surface cross-linking treatment, or added during granulation. Although a form etc. are mentioned, it does not specifically limit. Note that (b1) the composite hydrous oxide (B) containing zinc and silicon, or (b2) zinc and aluminum is not limited to the water absorbent resin (A) obtained after polymerization, , And may be added to the reaction product during the polymerization.

  The amount of (b1) zinc and silicon or (b2) the composite hydrous oxide (B) containing zinc and aluminum is preferably 0.001 to 5 parts by mass with respect to 100 parts by mass of the water absorbent resin (A). More preferably, it is 0.05-4 mass parts, More preferably, it is 0.1-3 mass parts. When the addition amount is less than 0.001 part by mass, there is a possibility that the deodorization performance that can sufficiently remove malodor derived from sulfur compounds such as hydrogen sulfide and mercaptans may be insufficient. When it exceeds 5 mass parts, there exists a possibility that the water absorption resin original absorption performance may be reduced.

  As an aspect of adding the composite hydrous oxide (B) to the water absorbent resin (A) obtained through the polymerization step, for example, the water absorbent resin is directly mixed so that a desired amount is added to the water absorbent resin. A method (for example, when blending powders, a dry blend method); a method in which water, an aqueous liquid, various organic solvents, or the like are sprayed or added dropwise to a water-absorbent resin directly mixed by such a method; Examples thereof include a method of dispersing in an aqueous liquid or various organic solvents to form a slurry and adding it to the water absorbent resin. Moreover, when mixing an aqueous liquid and various organic solvents, you may dry as needed.

  When mixing the water-absorbent resin with (b1) zinc and silicon, or (b2) the composite hydrous oxide (B) containing zinc and aluminum, an aqueous liquid such as water, water vapor, and hydrophilic organic solvent used as necessary The optimum amount of each organic solvent added varies depending on the type and particle size of the water-absorbent resin (A). When water is used, the addition amount is preferably 10% by mass or less, more preferably in the range of 1 to 5% by mass with respect to the water absorbent resin (A). When using a hydrophilic organic solvent, the addition amount is preferably 10% by mass or less, more preferably 0.1 to 5% by mass with respect to the water absorbent resin (A).

  The apparatus used when mixing the water-absorbing resin and (b1) zinc and silicon, or (b2) the composite hydrous oxide (B) containing zinc and aluminum may be a normal apparatus. For example, cylindrical type mixer, screw type mixer, screw type extruder, high speed stirring type mixer (for example, turbulizer etc.), nauter type mixer, V type mixer, ribbon type mixer, double arm type kneader , Fluid type mixer, airflow type mixer, rotary disk type mixer, roll mixer, rolling type mixer, ski type (saddle type) shovel blade type mixer (eg, Redige mixer), etc. The mixing speed can be high or low.

  The production method of the water-absorbent resin composition of the present invention further includes a deodorant, an antibacterial agent, a fragrance, a foaming agent, a pigment, a dye, a plasticizer, an adhesive, a surfactant, a fertilizer, and an oxidizer, as necessary. , Reducing agents, water, salts, chelating agents, bactericides, hydrophilic polymers such as polyethylene glycol and polyerylenimine, hydrophobic polymers such as paraffin, thermoplastic resins such as polyethylene and polypropylene, polyester resins and urea resins A step of adding a thermosetting resin or the like may be included. These additives are preferably added in an amount of 0 to 30% by mass, more preferably 0 to 20% by mass, and still more preferably 0 to 10% by mass with respect to the water absorbent resin.

  The content of the water-absorbent resin in the water-absorbent resin composition is not particularly limited, but is preferably in the range of 70 to 99% by mass, more preferably in the range of 80 to 99% by mass in order to fully exhibit the effects of the present invention. Especially preferably, it is the range of 90-99 mass%.

  In the water-absorbent resin composition according to the present invention, various inorganic powders may be added as necessary. Specific examples of the inorganic powder include metal oxides such as silicon dioxide and titanium oxide, silicic acid (salts) such as natural zeolite and synthetic zeolite, kaolin, talc, clay, bentonite and the like.

  The water-absorbing resin composition of the present invention has a non-pressure absorption capacity of 0.90% by mass sodium chloride aqueous solution, preferably 26 g / g or more, more preferably 28 g / g or more, and further preferably 30 g / g or more. Especially preferably, it is 32 g / g or more. If the absorbency against pressure of 0.90 mass% sodium chloride aqueous solution is less than 26 g / g, the effects of the present invention may not be sufficiently exhibited. The higher the absorption capacity under no pressure, the better. However, to increase the absorption capacity under no pressure to a certain level or more, there is a risk of causing a significant increase in cost and a decrease in other physical properties (for example, water-soluble components). In that case, the absorption capacity under no pressure may be 100 g / g or less, preferably 90 g / g or less.

  The water-absorbent resin composition of the present invention has an absorption capacity under pressure at 1.9 kPa with respect to a 0.90% by mass sodium chloride aqueous solution, preferably 20 g / g or more, more preferably 24 g / g or more, and still more preferably 26 g / g. g or more, particularly preferably 28 g / g or more. When the absorption capacity under pressure at 1.9 kPa with respect to the 0.90 mass% sodium chloride aqueous solution is smaller than 20 g / g, the effect of the present invention may not be sufficiently exhibited. The higher the absorption capacity under pressure, the better. However, in order to increase the absorption capacity under pressure to a certain level or more, there is a risk of causing a significant increase in cost and other physical properties. In that case, the absorption capacity under pressure is 60 g. / G or less, preferably 50 g / g or less.

  In order to maximize the effects of the present invention, the absorption capacity of the water-absorbent resin composition of the present invention with respect to a 0.90 mass% sodium chloride aqueous solution is 26 g / g or more under no pressure and 0.90 mass. It is particularly preferable that the absorption capacity under pressure at 1.9 kPa with respect to a% sodium chloride aqueous solution is 20 g / g or more. When the water absorbent resin composition of the present invention has such specific excellent absorption performance, the deodorization performance which is one of the effects of the present invention can be more fully exhibited.

  The shape of the water-absorbent resin composition is not particularly limited, and examples thereof include spheres, aggregates of spheres, and irregularly pulverized powder (particles). Crushed powder (particles) can be preferably used. Furthermore, the bulk specific gravity defined by JIS K-3362 is preferably within a range of 0.40 to 0.80 g / ml, more preferably 0.50 to 0 in order to sufficiently exert the effects of the present invention. Within the range of .75 g / ml, more preferably within the range of 0.60 to 0.73 g / ml.

  The water content of the water-absorbent resin composition is not particularly limited, but is preferably a powder that exhibits fluidity even at room temperature in order to fully exhibit the effects of the present invention. Specifically, the moisture content is preferably 0.2 to 30% by mass, more preferably 0.3 to 15% by mass, and still more preferably 0.5 to 10% by mass. The water content is defined as the amount of water contained in the water-absorbent resin composition, and is calculated, for example, by using the weight loss when dried at 180 ° C. for 3 hours using 1 g of the water-absorbent resin.

  The water-soluble content of the water-absorbent resin composition is not particularly limited, but is preferably as low as possible in order to sufficiently exhibit the effects of the present invention, preferably 0 to 50% by mass, more preferably 0 to 25% by mass. More preferably, it is 0-20 mass%, Most preferably, it is 0-15 mass%, Most preferably, it is 0-10 mass%. There is no particular lower limit on the amount of water-soluble component, and the lower the amount, ie, 0% by mass is preferable. Reduction of the water-soluble content may be accompanied by a large increase in cost and a decrease in absorption capacity, and the lower limit may be 0.1% by mass or more, preferably 1% by mass or more.

The colored state of the water-absorbent resin composition is preferably 0 to 15, more preferably 0 to 13, more preferably 0 to 10 as the YI value (see Yellow Index: European Patent No. 942014 and European Patent No. 1108745). Most preferably, it is 0-5. The amount of residual monomer in the water absorbent resin composition is preferably 1000 ppm or less (lower limit 0 ppm), more preferably 500 ppm or less (lower limit 0 ppm).

  The particle size of the water-absorbent resin composition is preferably 90% by mass or more of particles of less than 850 μm and 150 μm or more and 60% by mass or more of particles of 300 μm or more. The larger the number of particles less than 850 μm and 150 μm or more, the more preferable. That is, it is preferably 95 to 100% by mass, more preferably 98 to 100% by mass, based on the total mass of the particles. Moreover, the particle | grains of 300 micrometers or more are preferably 65 mass% or more with respect to the total mass of particle | grains, More preferably, it is 70 mass% or more, Most preferably, it is 75 mass% or more. The upper limit of this amount is not particularly high, and it is preferably as high as possible, that is, 100% by mass. However, there is a case where a significant cost increase is involved in achieving 100% by mass.

  When the number of particles of 300 μm or more is less than 60% by mass, it may be difficult to achieve the deodorizing effect of the present invention. Surprisingly, the deodorizing effect is improved as the particle size of the water-absorbent resin composition is increased and the specific surface area is decreased, although the surface area is reduced when the particle size is increased.

  The mass average particle diameter of the water absorbent resin composition is preferably 200 to 700 μm, more preferably 300 to 600 μm, and particularly preferably 400 to 500 μm. If necessary, the mass average particle diameter of the water absorbent resin composition may be adjusted by granulation.

  Since the water-absorbent resin composition has excellent deodorizing performance in actual use, the lower the value after 3 hours of the residual amount of wet hydrogen sulfide, the better, preferably 0 to 5 ppm, more preferably 0 to 3 ppm. Yes, more preferably 0 to 2 ppm, particularly preferably 0 to 1 ppm. Further, the lower the wet hydrogen sulfide residual amount after 1 hour is, the better, preferably 0 to 7 ppm, more preferably 0 to 5 ppm, and particularly preferably 0 to 3 ppm. Furthermore, the value after 30 minutes of the residual amount of wet hydrogen sulfide is preferably 0 to 9 ppm, more preferably 0 to 7 ppm, and particularly preferably 0 to 5 ppm.

  Since the water absorbent resin composition of the present invention has excellent deodorizing performance in actual use, the value after 60 minutes of the residual amount of wet ammonia is preferably 0 to 50 ppm, more preferably 0 to 40 ppm. Particularly preferably, it is 0 to 30 ppm. Furthermore, the value after 30 minutes of the residual amount of wet ammonia is preferably 0 to 100 ppm, more preferably 0 to 80 ppm, and particularly preferably 0 to 60 ppm. Furthermore, the value after 10 minutes of the residual amount of wet ammonia is preferably 0 to 300 ppm, more preferably 0 to 250 ppm, and particularly preferably 0 to 220 ppm. If these conditions are not satisfied, even when used in an actual diaper, the deodorizing performance is not sufficient in actual use, and there is a risk of causing human discomfort. By controlling the absorbent resin composition so as to satisfy the above parameters, a sufficient effect can be exhibited even in actual use such as diapers.

  Since the water-absorbent resin composition has a low separation rate of the composite hydrous oxide (B) containing (b1) zinc and silicon, or (b2) zinc and aluminum, the deodorizing performance is effectively expressed (details of the separation rate) See Examples). The separation rate of the composite hydrous oxide (B) containing zinc and silicon or zinc and aluminum is better as it is lower, preferably 0 to 20%, more preferably 0 to 15%, still more preferably 0 to 0%. 10%, particularly preferably 0 to 5%. When the separation rate of the composite hydrous oxide (B) containing zinc and silicon, or zinc and aluminum is larger than 20%, when the water absorbent resin composition absorbs an absorbing liquid such as urine and swells, The water-absorbent resin and the composite hydrous oxide (B) containing zinc and silicon or zinc and aluminum are separated, and the deodorizing effect of the composite hydrous oxide (B) containing zinc and silicon or zinc and aluminum is separated. May not be able to be exhibited effectively.

  Since the water absorbing resin composition has a low moisture absorption blocking rate described in Examples described later, it is excellent in powder handling properties. The lower the moisture absorption blocking rate, the better, preferably 0 to 30% by mass, more preferably 0 to 20% by mass, still more preferably 0 to 10% by mass, and particularly preferably 0 to 5% by mass. . When the moisture absorption blocking rate is larger than 30% by mass, for example, when producing a diaper or the like, there is a possibility that a bad effect such as difficulty in producing a diaper due to poor fluidity of the powder.

(5) Absorber The water-absorbent resin composition of the present invention contains the water-absorbent resin (A) as a main component, and its shape is usually a powder. An absorbent body can be obtained by molding such a powdery water-absorbing resin composition together with any other absorbent material. Although the shape of an absorber is not specifically limited, Preferably, it is a sheet form (other name web form), a cylinder shape, a film form, and a fiber form, Most preferably, it is a sheet form. When the aqueous resin composition is obtained in sheet form, it may be used as an absorbent as it is.

  In order to exhibit the effects of the present invention, the absorbent body is mainly composed of a water-absorbing resin (A) having an acid group and / or a salt thereof and a crosslinked structure, and (b1) zinc and silicon, or (b2) zinc and The composite hydrous oxide (B) containing aluminum and an absorbent comprising hydrophilic fibers.

  The hydrophilic fiber is not particularly limited, and examples thereof include pulverized wood pulp, cotton linter, crosslinked cellulose fiber, rayon, cotton, wool, acetate, and vinylon. Preferably, those obtained by airlaid are used.

  The absorbent body of the present invention may be produced using the water-absorbent resin composition and hydrophilic fibers described above, or the water-absorbent resin (A) having an acid group and / or salt thereof and a crosslinked structure (b1). It may be produced by using ()) zinc and silicon, or (b2) a composite hydrous oxide (B) containing zinc and aluminum, and hydrophilic fibers.

  When the absorbent body of the present invention is an absorbent body containing a water-absorbent resin composition and hydrophilic fibers, the content of the water-absorbent resin composition relative to the total mass of the water-absorbent resin composition and hydrophilic fibers, called the core concentration However, it is preferably in the range of 20 to 100% by mass, more preferably in the range of 25 to 90% by mass, and more preferably in the range of 30 to 80% by mass. When the core concentration is less than 20% by mass, the amount of the water-absorbent resin composition used is small, and for example, there is a possibility that imparting deodorizing performance to the whole diaper is insufficient.

When manufacturing the absorber of this invention from a water absorbing resin composition and a hydrophilic fiber, the manufacturing method is not specifically limited. For example, the water-absorbent resin composition and the hydrophilic fiber are dry-mixed using a mixer such as a mixer at a ratio that provides the above-described core concentration. The resulting mixture is formed into a web by, for example, air papermaking. Then, an absorber is manufactured by compressing if necessary. Such an absorber is preferably compression-molded in a range of density 0.001 to 0.50 g / cc and basis weight 0.01 to 0.20 g / cm ² .

  When the absorbent body of the present invention is produced using the water absorbent resin (A) or the water absorbent resin composition, the composite hydrous oxide (B), and the hydrophilic fiber, 0.90 of the water absorbent resin (A). It is preferable that the absorption capacity under pressure at 1.9 kPa with respect to a mass% sodium chloride aqueous solution is 20 g / g or more. Moreover, it is preferable that the mass ratio of zinc and silicon or zinc and aluminum in the composite hydrous oxide (B) is 50/50 to 99/1. Moreover, it is preferable that the absorption capacity | capacitance (60-minute value) under pressure in 1.9 kPa with respect to 0.90 mass% sodium chloride aqueous solution of a water absorbing resin is the above-mentioned range. If the mass ratio of zinc and silicon or zinc and aluminum in the composite hydrous oxide (B) is out of the above range, the effect of the present invention may not be sufficiently exhibited as an absorber.

  When the absorber of the present invention is produced using the water absorbent resin (A), the composite hydrous oxide (B), and the hydrophilic fiber, the production method is not particularly limited. For example, a method of dry-mixing the water-absorbent resin (A), the composite hydrous oxide (B), and the hydrophilic fiber using a mixer such as a mixer at a ratio of the above-mentioned core concentration; A method in which water, an aqueous liquid, various organic solvents, etc. are sprayed or dropped and mixed; a slurry in which a composite hydrous oxide (B) is dispersed in an aqueous liquid, various organic solvents, etc., a water absorbent resin, and a hydrophilic fiber And a method of mixing using a mixer such as a mixer at a ratio of the above-mentioned core concentration.

(6) Absorbent article The absorbent article of the present invention includes the above-described absorbent body of the present invention, a liquid-permeable surface sheet, and a liquid-impermeable back sheet.

  The manufacturing method of an absorbent article is not specifically limited. For example, the absorber functioning as a top sheet is sandwiched between a liquid-permeable base material and a liquid-impermeable base material functioning as a back sheet. If necessary, an elastic member, a diffusion layer, an adhesive tape, and the like are disposed, and an absorbent article such as an adult paper diaper or a sanitary napkin is manufactured.

  The water-absorbent resin composition and absorbent body of the present invention can impart a deodorizing function to an absorbent article and exhibit excellent deodorizing performance and absorption characteristics over a long period of time. Specific examples of uses include hygiene materials such as adult paper diapers, children's diapers, sanitary napkins and so-called incontinence pads, which have been growing rapidly in recent years, but are not particularly limited thereto. In the absorbent article of the present invention, the water-absorbent resin composition and the absorbent body have very excellent deodorizing properties, have a small amount of return, and have a dry feeling. As a result, the burden on the wearer and the caregiver can be greatly reduced.

  EXAMPLES Examples and comparative examples of the present invention will be specifically described below, but the present invention is not limited to the following examples. Various performances of the water absorbent resin, the water absorbent resin composition and the absorbent article were measured by the following methods. Moreover, all the electric equipments used in the examples were used under conditions of 100 V and 60 Hz. Further, the water absorbent resin, the water absorbent resin composition, and the absorbent article were used under the conditions of 25 ° C. ± 2 ° C. and RH 50% unless otherwise specified.

(A) Absorption capacity under no pressure with respect to 0.90 mass% sodium chloride aqueous solution (physiological saline) 0.20 g of water absorbent resin (or water absorbent resin composition) is uniformly put in a non-woven bag (60 mm × 60 mm). It was immersed in a 0.9 mass% sodium chloride aqueous solution (physiological saline) adjusted to 25 ± 2 ° C. After 60 minutes, the bag was pulled up, drained at 250 G for 3 minutes using a centrifuge, and then the mass W2 (g) of the bag was measured. Further, the same operation was performed without using the water absorbent resin (or the water absorbent resin composition), and the mass W1 (g) at that time was measured. And from these masses W1 and W2, the absorption capacity (g / g) was calculated according to the following formula.

Absorption capacity (g / g) under non-pressure with respect to 0.90 mass% sodium chloride aqueous solution (physiological saline) = ((mass W2 (g) −mass W1 (g)) / water absorbent resin (or water absorbent resin composition) ) Mass (g))-1
(B) Absorption capacity under load at 1.9 kPa against 0.90% by mass sodium chloride aqueous solution (saline) A 400-mesh stainless steel wire mesh (mesh size 38 μm) is welded to one side (bottom) of a cylindrical section. Further, 0.90 g of a water-absorbing resin (or water-absorbing resin composition) was sprayed uniformly on a wire mesh at the bottom of a plastic support cylinder having an inner diameter of 60 mm. A piston (cover plate) that has an outer diameter slightly smaller than 60 mm and does not create a gap on the wall surface with the support cylinder and does not hinder vertical movement is placed on the support cylinder and the water absorbent resin (or water absorbent resin). The composition) and the mass W3 (g) of the piston were measured. On this piston, a load adjusted so that a load of 1.9 kPa including the piston can be uniformly applied to the water absorbent resin (or the water absorbent resin composition) is placed. Completed. Place a glass filter with a diameter of 90 mm and a thickness of 5 mm inside a Petri dish with a diameter of 150 mm, and 0.9 mass% sodium chloride aqueous solution (saline) adjusted to 25 ± 2 ° C at the same level as the upper surface of the glass filter. It was added to become. On top of that, a sheet of 9 cm diameter filter paper (Toyo Filter Paper Co., Ltd., No. 2) was placed so that the entire surface was wetted, and excess liquid was removed.

  The set of measuring devices was placed on the wet filter paper, and the liquid was absorbed under load. When the liquid level dropped from the top of the glass filter, the liquid was added to keep the liquid level constant. After 1 hour, the set of measuring devices was lifted, and the weight W4 (g) (the weight of the support cylinder, the swollen water-absorbent resin (or water-absorbent resin composition) and the piston) after removing the load was measured again. And from these masses W3 and W4, the absorption capacity (g / g) under pressure at 1.9 kPa with respect to a 0.90 mass% sodium chloride aqueous solution (physiological saline) was calculated according to the following formula.

Absorption capacity under load at 1.9 kPa (g / g) with respect to 0.90 mass% sodium chloride aqueous solution (physiological saline) = (mass W4 (g) −mass W3 (g)) / water absorbent resin (or water absorbent) Resin composition) mass (g)
(C) Mass average particle diameter The water-absorbent resin (or water-absorbent resin composition) is sieved with a JIS standard sieve such as 850 μm, 600 μm, 500 μm, 425 μm, 300 μm, 212 μm, 150 μm, 106 μm, 75 μm, and the residual percentage is determined. Plotted on log probability paper. Thereby, the mass average particle diameter (D50) was read.

  For screening, 10.00 g of the water-absorbent resin powder (or water-absorbent resin composition powder) is a JIS standard sieve (The IIDA TESTING SIEVE) having an opening of 850 μm, 600 μm, 500 μm, 425 μm, 300 μm, 212 μm, 150 μm, 106 μm, 75 μm, etc. : 80 mm in inner diameter), and classified for 10 minutes with a low tap type sieve shaker (manufactured by Iida Seisakusho, ES-65 type sieve shaker). The mass average particle diameter (D50) is a particle diameter of a standard sieve corresponding to 50% by mass of the whole particle with a standard sieve having a constant mesh as described in US Pat. No. 5,051,259.

(D) Deodorization test (evaluation of water absorbent resin or water absorbent resin composition)
50 ml of human urine collected from 20 adults is added to a 120 ml polypropylene cup with a lid, and 2.0 g of the water-absorbent resin (or water-absorbent resin composition) obtained in Examples or Comparative Examples described later is added thereto. As a result, a swollen gel was formed. Human urine was used within 2 hours after excretion. The container was capped and the swollen gel was kept at 37 ° C. After 6 hours from liquid absorption, the lid was opened, and 20 adult panelists smelled about 3 cm from the top of the cup to determine the deodorizing effect. For the determination, the score was described in 6 stages for each person using the following criteria, and the average value was obtained. In addition, the deodorizing effect was evaluated with a standard product obtained by performing the same operation using only human urine without adding a water-absorbent resin (or water-absorbent resin composition).

0: Odorless 1: Smell that can be finally detected 2: Smell that can be detected but acceptable 3: Smell that can be easily detected 4: Strong odor 5: Strong odor (e) Deodorization test (evaluation of absorbent articles)
Absorbent articles obtained in Examples or Comparative Examples described later were cut into a circle (diameter 80 mm), and a liquid-permeable sheet was placed on the bottom of a 500 ml polypropylene cup with a lid. 20 g of human urine collected from 20 adults was placed in the center of this absorbent article, and the whole container was kept at 37 ° C. with a lid. After 6 hours, the lid was opened, and the deodorizing effect was determined by the panel of 20 adults smelling about 3 cm from the top of the cup. For the determination, the score was described in 6 stages for each person using the following criteria, and the average value was obtained. In addition, the thing which performed the same operation only with human urine without putting an absorbent article was made into the standard goods, the smell was set to 5, and the deodorizing effect was evaluated.

0: Odorless 1: Smell that can be finally sensed 2: Smell that can be sensed but acceptable 3: Smell that can be easily sensed 4: Strong odor 5: Strong odor (f) Residual amount of wet hydrogen sulfide (hydrogen sulfide deodorization ability test)
Glass petri dish (described in GENERAL CATALLOGUE A-8000 (issued in 2002) issued by Mutual Science Glass Co., Ltd.), code: 305-08, outer diameter x height = 150 mm x 28 mm), water absorbent resin (or water absorbent resin) Composition) 5.00 g was uniformly distributed. Next, the water-absorbent resin (or water-absorbent resin composition) is covered with one sheet of breathable and liquid-permeable heatron paper (Nangoku Pulp Industry Co., Ltd., GSP-22) cut into a circle (diameter 147 mm), Three places of the circumference of the heatron paper were fixed to the inner wall of the glass petri dish with tape (10 mm × 10 mm). If it was not Heatlon paper, a non-woven fabric was substituted. After opening a side of a 3L odor bag (Omi Odo Air Service Co., Ltd.) and placing a glass petri dish coated with a water absorbent resin (or water absorbent resin composition), there is no gap in the opening of the odor bag So closed. From the glass tube portion provided in the odor bag, the inside of the odor bag was once depressurized, and then a predetermined amount of odorless air was injected. The supply amount of odorless air was set so that the total amount with the hydrogen sulfide standard gas to be injected later was 2.5L. That is, the odorless air amount (L) was set according to the injection amount (L) of 2.5-hydrogen sulfide standard gas. Subsequently, using a glass funnel equipped with a polytetrafluoroethylene tube in a petri dish in an odor bag while preventing external air from being mixed, a 0.90 mass% sodium chloride aqueous solution (saline) adjusted to 25 ± 2 ° C. 80 ml was poured all at once, and the water-absorbent resin (or water-absorbent resin composition) was uniformly swollen and sealed with a silicone rubber stopper. After 30 minutes of swelling, 1.0 ml of hydrogen sulfide standard gas (hydrogen sulfide concentration: 5.06 (volume%), hydrogen sulfide concentration in the odor bag: 20 ppm) was placed in the odor bag with an injection needle. It injected with the syringe and left at 25 degreeC. The standard gas concentration and the injection amount were appropriately changed so that the concentration in the bag was 20 ppm. 30 minutes later, 1 hour later, 3 hours later, the silicone rubber stoppers were removed, and while preventing the outside air from being mixed in, the gas sampling device (manufactured by Gastec Co., Ltd., GV-100S) and the gas detector tube (manufactured by Gastech Co., Ltd., No. 4LK) was used to measure the atmospheric concentration. And this atmospheric concentration was made into wet hydrogen sulfide residual amount.

(G) Remaining amount of wet ammonia Glass petri dish (described in GENERAL CATALLOGUE A-8000 (issued in 2002) issued by Mutual Riken Glass Co., Ltd., code: 305-08, outer diameter x height = 150 mm x 28 mm), water absorption 5.00 g of water-soluble resin (or water-absorbent resin composition) was evenly distributed. Next, the water-absorbent resin (or water-absorbent resin composition) is covered with one sheet of heatron paper (Nangoku Pulp Industries Co., Ltd., variety: GSP-22) having a breathability and liquid permeability cut into a circle (diameter 147 mm). The three places around the circumference of the heatron paper were fixed to the inner wall of the glass petri dish with tape (10 mm × 10 mm). If it was not Heatlon paper, a non-woven fabric was substituted. Open one side of a 3L odor bag (Omi Odo Air Service Co., Ltd.), put a glass petri dish with a water-absorbing resin (or water-absorbing resin composition), and make sure there is no gap in the opening of the odor bag Closed to. Once the inside of the odor bag is depressurized from the glass tube part provided in the odor bag, 2.5 L of a predetermined amount of odorless air is injected, and then, while preventing contamination of the outside air, Using a glass funnel equipped with a tetrafluoroethylene tube, 80 ml of a 0.90 mass% sodium chloride aqueous solution (saline) in which 0.0132 mol of ammonia was adjusted to 25 ± 2 ° C. was poured all at once. The resin (or water-absorbing resin composition) was uniformly swollen, sealed with a silicone rubber stopper, and allowed to stand at 25 ° C. After 10 minutes, 30 minutes and 60 minutes, respectively, the silicone rubber stopper is removed to prevent the outside air from being mixed, and the gas sampling device (manufactured by Gastec Corporation, GV-100S) and the gas detector tube (manufactured by Gastech Corporation, No. 3L, No. 3La, No. 3M) were used to measure the atmospheric concentration. And this atmospheric concentration was made into wet ammonia residual amount.

(H) Separation rate: (an index indicating the rate at which the additive added to the water-absorbent resin falls off the water-absorbent resin during swelling)
In a transparent glass Erlenmeyer flask (manufactured by Mutual Riken Glass Co., Ltd.) having a capacity of 200 ml, 0.50 parts by mass of a water-absorbent resin composition and a 0.90% by mass sodium chloride aqueous solution (physiologically adjusted to 25 ± 2 ° C.) 50 ml of saline) was added. Further, a stirrer (manufactured by Mutual Rikagaku Glass Mfg. Co., Ltd., standard type, 3 cm in length) was added, sealed with a silicon rubber stopper, and stirred for 10 minutes at 300 rpm using a magnetic stirrer. After stirring, place it in an ultrasonic cleaner (manufacturer: Nippon Seisen Co., Ltd., distributor: Bariba Co., Ltd., trade name: ULTRA-SONIC CLEANER 7500bariba), and it will be the same level as the liquid level in the Erlenmeyer flask Pure water was put into the bath of the ultrasonic cleaner, and the ultrasonic cleaner was operated for 20 minutes. Then, in order to make the whole liquid uniform, the mixture was again stirred at 300 rpm for 1 minute, and immediately after 1 minute, suction filtration (filter paper made by ADVANTEC, No. 2) was performed to collect all the filtrate, and the filtrate Mass W5 (g) was weighed. The haze value of the obtained filtrate was measured by DEGITAL HAZEMETER (manufactured by Nippon Denshoku Industries Co., Ltd., AUTOMATIC DIGITAL HAZEMETER NDH-20D), and the kaolin turbidity was calculated from the relationship between the haze value and kaolin turbidity. From the calibration curve obtained by the method, the concentration X1 (ppm) of the additive in the filtrate, that is, the amount of the additive separated from the water-absorbent resin in 0.90% by mass sodium chloride aqueous solution (saline) Was calculated.

  A calibration curve between the added amount of each additive and kaolin turbidity was prepared as follows. Transparent glass with a capacity of 200 ml of 50 ml of a 0.90 mass% sodium chloride aqueous solution (saline) adjusted to 25 ± 2 ° C. containing a predetermined amount (equivalent to 20 ppm, 50 ppm, 100 ppm, 300 ppm) of additive. It was prepared in a manufactured Erlenmeyer flask (manufactured by Mutual Science Glass Co., Ltd.). Further, a stirrer (manufactured by Mutual Rikagaku Glass Co., Ltd., standard type, length 3 cm) was added, sealed with a silicon rubber stopper, and stirred for 10 minutes at 300 rpm using a magnetic stirrer. After stirring, place it in an ultrasonic cleaner (manufacturer: Nippon Seisen Co., Ltd., distributor: Bariba Co., Ltd., trade name: ULTRA-SONIC CLEANER 7500bariba), and it will be the same level as the liquid level in the Erlenmeyer flask Pure water was put into the bath of the ultrasonic cleaner, and the ultrasonic cleaner was operated for 20 minutes. Then, in order to make the whole liquid uniform, again using a magnetic stirrer, the mixture was stirred at 300 rpm for 1 minute, and immediately after 1 minute, suction filtration was performed (filter paper manufactured by ADVANTEC, No. 2). All were recovered. The haze value of the obtained filtrate was measured by DEGITAL HAZEMETER (manufactured by Nippon Denshoku Industries Co., Ltd., AUTOMATIC DIGITAL HAZEMETER NDH-20D), the kaolin turbidity was calculated from the relationship between the haze value and kaolin turbidity, The relationship between the additive amount and kaolin turbidity was linearly approximated by the least square method, and a calibration curve for each additive was prepared.

  The separation rate was calculated using the following formula.

Separation rate (%) = X1 / Y1 × 100
X1 (ppm): concentration of additive in filtrate calculated by experiment Y1 (ppm): concentration of filtrate when all additives are separated from the water-absorbent resin and dispersed in the filtrate Y1 (ppm) = 0.50 × A1 / 100 / W5 × 1000000
A1 (mass%): Addition amount of additive (to water-absorbing resin)
W5 (g): Amount of filtrate It shows that the one where the value of the separation rate is smaller has less dropout of the additive from the water absorbent resin, and the effect of the additive is effectively exhibited.

(I) Moisture absorption blocking rate (% by mass)
A constant temperature and humidity chamber (Tabaye Spec), 2 g of water absorbent resin (or water absorbent resin composition) was evenly sprayed on the bottom of an aluminum cup with a bottom diameter of 52 mm and a height of 22 mm and adjusted to 25 ° C. and 90% relative humidity in advance. The product was quickly placed in PLATIOOUS LUCIFER PL-2G) and left for 60 minutes. Thereafter, the water-absorbing water-absorbing resin (or water-absorbing resin composition) was transferred to a JIS standard sieve having a diameter of 7.5 cm and an opening of 2000 μm. At this time, when the water-absorbing water-absorbing resin (or water-absorbing resin composition) adheres firmly to the aluminum cup and cannot be transferred to a sieve, the water-absorbing resin (or the water-absorbing resin composition) is in a state of moisture absorption and blocking. ) Was peeled off and transferred to a sieve, taking care not to break it as much as possible. This was immediately sieved for 8 seconds with a vibration classifier (IIDA SIEVE SHAKER, TYPE: ES-65 type, SER. No. 0501), and the weight of the water absorbent resin (or water absorbent resin composition) remaining on the sieve was W6. The weight W7 (g) of the water absorbent resin (or water absorbent resin composition) that passed through (g) and the sieve was measured.

Moisture absorption blocking rate (mass%) = weight W6 (g) / (weight W6 (g) + weight W7 (g)) × 100
Was used to calculate the moisture absorption blocking rate (mass%). The lower the moisture absorption blocking rate, the better the moisture absorption fluidity, and the handleability of the powder is improved.

(J) Gel strength 10 ml of artificial urine containing 0.005% by mass of L-ascorbic acid (artificial urine composition: urea 95 g, sodium chloride 40 g, magnesium sulfate 5 g, calcium chloride 5 g, ion-exchanged water 4855 g) In a plastic container with a lid, 2 g of each water-absorbing resin composition was expanded 25 times and left in an atmosphere at a temperature of 37 ° C. and a relative humidity of 90% for a predetermined time. After 24 hours, the degree of urine deterioration of the water-absorbent resin was quantified by the amount of time (seconds) that the tip of the fluidized gel moved 2 cm when the container was tilted 90 degrees, and the state of the swollen gel was also tactile (○ : Good, Δ: normal, ×: bad). In addition, urine resistance and durability are so high that time (second) is large.

[Reference Example 1]
In 5500 g of an aqueous solution of sodium acrylate having a neutralization rate of 75 mol% (monomer concentration 38 mass%), 3.4 g of polyethylene glycol diacrylate (average added mole number of ethylene oxide 8) was dissolved to obtain a reaction solution. Next, this reaction solution was degassed for 30 minutes in a nitrogen gas atmosphere. Next, the reaction solution was supplied to a reactor formed by attaching a lid to a stainless steel double-armed kneader with an internal volume of 10 L having two sigma-shaped blades, and the system was nitrogenated while maintaining the reaction solution at 30 ° C. The gas was replaced. Subsequently, 2.46 g of sodium persulfate and 0.10 g of L-ascorbic acid were added while stirring the reaction solution, and polymerization started about 1 minute later. Then, polymerization was carried out at 30 ° C. to 90 ° C., and the hydrogel polymer was taken out 60 minutes after the start of the polymerization. The obtained hydrogel polymer was subdivided into particles of 1 to 4 mm. The finely divided hydrogel polymer was spread on a 50 mesh (mesh size: 300 μm) wire net and dried with hot air at 150 ° C. for 90 minutes. Next, the dried product was pulverized using a vibration mill, and further classified and prepared with a 20 mesh (mesh size 850 μm) wire mesh to obtain an irregularly crushed water absorbent resin powder (a).

  To 100 parts by mass of the obtained water-absorbent resin powder (a), 0.5 part by mass of propylene glycol, 0.03 part by mass of ethylene glycol diglycidyl ether, 0.3 part by mass of 1,4-butanediol, and 3 parts of water 3.83 parts by mass of a surface cross-linking agent consisting of parts by mass was mixed. The above mixture was heat-treated at 210 ° C. for 55 minutes to obtain a water absorbent resin (1). Table 1 shows the absorption capacity under no pressure, the absorption capacity under pressure, and the particle size distribution of the water absorbent resin (1).

[Reference Example 2]
5.9 g of polyethylene glycol diacrylate (average added mole number of ethylene oxide 8) was dissolved in 5500 g of an aqueous solution of sodium acrylate having a neutralization rate of 65 mol% (monomer concentration 38 mass%) to prepare a reaction solution. Next, after degassing this reaction solution in the same manner as in Reference Example 1, the above reaction solution was supplied to the reactor of Reference Example 1, and the system was replaced with nitrogen gas while keeping the reaction solution at 30 ° C. Subsequently, 2.46 g of sodium persulfate and 0.10 g of L-ascorbic acid were added while stirring the reaction solution, and polymerization started about 1 minute later. Then, polymerization was carried out at 30 ° C. to 90 ° C., and the hydrogel polymer was taken out 60 minutes after the start of the polymerization. The obtained hydrogel polymer was fragmented into particles of about 1 to 4 mm. This hydrogel polymer was dried and crushed in the same manner as in Reference Example 1, and further classified and prepared with a 20 mesh (mesh size 850 μm) wire mesh to obtain an irregularly crushed water absorbent resin powder (b). Obtained.

  A surface cross-linking agent 3.8 consisting of 0.5 parts by mass of propylene glycol, 0.3 parts by mass of 1,4-butanediol, and 3 parts by mass of water is added to 100 parts by mass of the obtained water absorbent resin powder (b). Mass parts were mixed. The above mixture was heat-treated at 200 ° C. for 45 minutes to obtain a water absorbent resin (2). The results are shown in Table 1.

[Reference Example 3]
3.6 g of polyethylene glycol diacrylate (average added mole number of ethylene oxide 8) was dissolved in 5500 g of an aqueous solution of sodium acrylate having a neutralization rate of 60 mol% (monomer concentration: 33% by mass) to prepare a reaction solution. Next, after degassing this reaction solution in the same manner as in Reference Example 1, the above reaction solution was supplied to the reactor of Reference Example 1, and the system was replaced with nitrogen gas while keeping the reaction solution at 30 ° C. Subsequently, 2.46 g of sodium persulfate and 0.10 g of L-ascorbic acid were added while stirring the reaction solution, and polymerization started about 1 minute later. And it superposed | polymerized at 30 to 85 degreeC, 60 minutes after superposition | polymerization was started, the hydrogel polymer was taken out. The obtained hydrogel polymer was fragmented into particles of about 1 to 4 mm. This hydrogel polymer was dried and pulverized in the same manner as in Reference Example 1, and further classified and blended with a 20 mesh (mesh size 850 μm) wire mesh, whereby an irregularly crushed water absorbent resin powder (c) Got.

  To 100 parts by mass of the obtained water absorbent resin powder (c), 3.83 parts by mass of a surface cross-linking agent having the same composition as in Reference Example 1 was mixed. The mixture was heat treated at 195 ° C. for 40 minutes to obtain a water absorbent resin (3). The results are shown in Table 1.

[Reference Example 4]
3.3 g of polyethylene glycol diacrylate (average number of moles of ethylene oxide added 8) was dissolved in 5500 g of an aqueous solution of sodium acrylate having a neutralization rate of 55 mol% (monomer concentration: 30% by mass) to prepare a reaction solution. Next, after degassing this reaction solution in the same manner as in Reference Example 1, the above reaction solution was supplied to the reactor of Reference Example 1, and the system was replaced with nitrogen gas while keeping the reaction solution at 30 ° C. Subsequently, 2.46 g of sodium persulfate and 0.10 g of L-ascorbic acid were added while stirring the reaction solution, and polymerization started about 1 minute later. And it superposed | polymerized at 30 to 85 degreeC, 60 minutes after superposition | polymerization was started, the hydrogel polymer was taken out. The obtained hydrogel polymer was fragmented into particles of about 1 to 4 mm. This hydrogel polymer was dried and pulverized in the same manner as in Reference Example 1, and further classified and blended with a 20 mesh (mesh size 850 μm) wire mesh, whereby an irregularly crushed water absorbent resin powder (d) Got.

  To 100 parts by mass of the obtained water absorbent resin powder (d), 3.8 parts by mass of a surface cross-linking agent having the same composition as in Reference Example 2 was mixed. The mixture was heat treated at 195 ° C. for 40 minutes to obtain a water absorbent resin (4). The results are shown in Table 1.

[Reference Example 5]
In 6600 g of an aqueous solution of sodium acrylate having a neutralization ratio of 68 mol% (monomer concentration: 35.5% by mass), 5.3 g of polyethylene glycol diacrylate (average number of moles of ethylene oxide added 8) was dissolved in a reaction solution. did. Next, after degassing this reaction solution in the same manner as in Reference Example 1, the above reaction solution was supplied to the reactor of Reference Example 1, and the system was replaced with nitrogen gas while keeping the reaction solution at 30 ° C. Subsequently, while stirring the reaction solution, 3.23 g of sodium persulfate and 0.016 g of L-ascorbic acid were added, and polymerization started about 1 minute later. Then, polymerization was carried out at 30 ° C. to 90 ° C., and the hydrogel polymer was taken out 40 minutes after the start of the polymerization. The obtained hydrogel polymer was fragmented into particles of about 1 to 4 mm. This hydrogel polymer was spread on a 50 mesh (mesh size 300 μm) wire net and dried with hot air at 170 ° C. for 40 minutes. Next, the dried product was pulverized using a vibration mill, and further classified and prepared with a 20 mesh (mesh size 850 μm) wire mesh to obtain an amorphous crushed water absorbent resin powder (e).

  A surface cross-linking agent 3 comprising 100 parts by mass of the obtained water absorbent resin powder (e), 0.51 part by mass of propylene glycol, 0.31 part by mass of 1,4-butanediol, and 2.73 parts by mass of water. .55 parts by weight were mixed. The mixture was heat treated at 200 ° C. for 40 minutes to obtain a water absorbent resin (5). The results are shown in Table 1.

[Reference Example 6]
5.6 g of polyethylene glycol diacrylate (average added mole number of ethylene oxide 8) was dissolved in 6600 g of an aqueous solution of sodium acrylate having a neutralization rate of 72 mol% (monomer concentration 38 mass%) to prepare a reaction solution. Next, after degassing this reaction solution in the same manner as in Reference Example 1, the above reaction solution was supplied to the reactor of Reference Example 1, and the system was purged with nitrogen gas while keeping the reaction solution at 30 ° C. Subsequently, 3.42 g of sodium persulfate and 0.017 g of L-ascorbic acid were added while stirring the reaction solution, and polymerization started about 1 minute later. And it superposed | polymerized at 30 degreeC-90 degreeC, the water-containing gel-like polymer was taken out 40 minutes after starting polymerization. The obtained hydrogel polymer was subdivided into particles of about 1 to 4 mm. This hydrogel polymer is spread on a 50 mesh (mesh size 300 μm) wire mesh, dried and crushed in the same manner as in Reference Example 1, and classified and mixed with a 20 mesh (mesh size 850 μm) wire mesh. Thus, an irregularly shaped water-absorbent resin powder (f) was obtained.

  To 100 parts by mass of the obtained water absorbent resin powder (f), 3.55 parts by mass of a surface cross-linking agent having the same composition as in Reference Example 5 was mixed. The above mixture was heat-treated at 200 ° C. for 50 minutes to obtain a water absorbent resin (6). The results are shown in Table 1.

[Reference Example 7]
In 5500 g of an aqueous solution of sodium acrylate having a neutralization rate of 65 mol% (monomer concentration: 33% by mass), 3.1 g of polyethylene glycol diacrylate (average added mole number of ethylene oxide 8) was dissolved to obtain a reaction solution. Next, after degassing this reaction solution in the same manner as in Reference Example 1, the above reaction solution was supplied to the reactor of Reference Example 1, and the system was replaced with nitrogen gas while keeping the reaction solution at 30 ° C. Subsequently, 2.46 g of sodium persulfate and 0.10 g of L-ascorbic acid were added while stirring the reaction solution, and polymerization started about 1 minute later. And it superposed | polymerized at 30 to 85 degreeC, 60 minutes after superposition | polymerization was started, the hydrogel polymer was taken out. The obtained hydrogel polymer was fragmented into particles of about 1 to 4 mm. This hydrogel polymer is spread on a 50 mesh (mesh size 300 μm) wire mesh, dried and ground in the same manner as in Reference Example 1, and further classified and blended with a 20 mesh (mesh size 850 μm) wire mesh. Thus, an irregularly crushed water-absorbent resin powder (g) was obtained.

  To 100 parts by mass of the obtained water-absorbent resin powder (g), 3.83 parts by mass of a surface cross-linking agent having the same composition as in Reference Example 1 was mixed. The above mixture was heat-treated at 195 ° C. for 60 minutes to obtain a water absorbent resin (7). The results are shown in Table 1.

[Reference Example 8]
6.8 g of polyethylene glycol diacrylate (average added mole number of ethylene oxide 8) was dissolved in 5500 g of an aqueous solution of sodium acrylate having a neutralization rate of 30 mol% (monomer concentration 20% by mass) to prepare a reaction solution. Next, after degassing this reaction solution in the same manner as in Reference Example 1, the above reaction solution was supplied to the reactor of Reference Example 1, and the system was replaced with nitrogen gas while keeping the reaction solution at 30 ° C. Subsequently, 2.46 g of sodium persulfate and 0.10 g of L-ascorbic acid were added while stirring the reaction solution, and polymerization started about 1 minute later. Then, polymerization was carried out at 30 ° C. to 80 ° C., and the hydrogel polymer was taken out 60 minutes after the start of the polymerization. The obtained hydrogel polymer was fragmented into particles of about 1 to 4 mm. This finely divided hydrogel polymer is spread on a 50 mesh (mesh size 300 μm) wire mesh, dried and crushed in the same manner as in Reference Example 1, and further with a 20 mesh (mesh size 850 μm) wire mesh. By classifying and blending, an irregularly crushed water-absorbent resin powder (h) was obtained.

  To 100 parts by mass of the obtained water absorbent resin powder (h), 3.8 parts by mass of a surface cross-linking agent having the same composition as in Reference Example 2 was mixed. The above mixture was heat-treated at 210 ° C. for 50 minutes to obtain a water absorbent resin (8). The results are shown in Table 1.

[Reference Example 9]
In the same manner as in Reference Example 1, an irregularly shaped water absorbent resin powder (i) was obtained. The obtained water absorbent resin powder (i) was directly used as the water absorbent resin (9). The results are shown in Table 1.

[Reference Example 10]
1 L of pure water was collected in a 5 L beaker and heated to 60 ° C. while stirring. Next, 2 L of an aqueous solution prepared by mixing 114.5 parts by mass of separately prepared zinc sulfate (manufactured by Wako Pure Chemical Industries, Ltd.) and 17.6 parts by mass of sodium silicate powder (manufactured by Wako Pure Chemical Industries, Ltd.) and an aqueous ammonia solution The solution was added dropwise with care so as to maintain the pH of 7.5 in the pure water. The produced precipitate was filtered and washed and then dried at 120 ° C. for 6 hours to obtain a composite hydrous oxide (B1) containing zinc and silicon (mass ratio of zinc and silicon: 85/15).

[Reference Example 11]
1 L of pure water was collected in a 5 L beaker and heated to 60 ° C. while stirring. Next, an aqueous solution in which 132.9 parts by mass of separately prepared zinc sulfate (manufactured by Wako Pure Chemical Industries, Ltd.) and 110.1 parts by mass of aluminum sulfate · 14-18 hydrate (manufactured by Wako Pure Chemical Industries, Ltd.) were mixed. 2 L and an aqueous ammonia solution were added dropwise with care so as to maintain a pH of 7.5 in the pure water. The produced precipitate was filtered and washed, and then dried at 120 ° C. for 6 hours to obtain a composite hydrous oxide (B2) containing zinc and aluminum (mass ratio of zinc and aluminum: 85/15).

[Reference Example 12]
1 L of pure water was collected in a 5 L beaker and heated to 60 ° C. while stirring. Then, 2L of an aqueous solution in which 161.2 parts by mass of separately prepared titanium chloride (manufactured by Wako Pure Chemical Industries, Ltd.) and 9.1 parts by mass of sodium silicate powder (manufactured by Wako Pure Chemical Industries, Ltd.) were mixed with an aqueous ammonia solution. The solution was added dropwise with care so as to maintain the pH of 7.5 in the pure water. The produced precipitate was filtered and washed, and then dried at 120 ° C. for 6 hours to obtain a composite hydrous oxide (B3) containing titanium and silicon (mass ratio of titanium and silicon: 91/9).

[Reference Example 13]
In 5500 g of an aqueous solution of sodium acrylate having a neutralization rate of 75 mol% (monomer concentration: 38% by mass), 2.3 g of polyethylene glycol diacrylate (average added mole number of ethylene oxide 8) was dissolved to obtain a reaction solution. Next, after degassing this reaction solution in the same manner as in Reference Example 1, the above reaction solution was supplied to the reactor of Reference Example 1, and the system was replaced with nitrogen gas while keeping the reaction solution at 30 ° C. Subsequently, 2.83 g of sodium persulfate and 0.024 g of L-ascorbic acid were added while stirring the reaction solution, and polymerization started about 1 minute later. Then, polymerization was performed at 30 ° C. to 100 ° C., and the hydrogel polymer was taken out 60 minutes after the start of the polymerization. The obtained hydrogel polymer was fragmented into particles of about 1 to 4 mm. This hydrogel polymer is spread on a 50 mesh (mesh size 300 μm) wire mesh, dried and ground in the same manner as in Reference Example 1, and further classified and blended with a 20 mesh (mesh size 850 μm) wire mesh. Thus, an irregularly crushed water-absorbent resin powder (j) was obtained.

  To 100 parts by mass of the obtained water absorbent resin powder (j), 3.8 parts by mass of a surface cross-linking agent having the same composition as in Reference Example 1 was mixed. The above mixture was heat-treated at 195 ° C. for 30 minutes to obtain a water absorbent resin (10). The results are shown in Table 1.

[Example 1]
To 100 parts by mass of the water-absorbent resin (1) obtained in Reference Example 1, a composite hydrous oxide of zinc and silicon (trade name: CERATIOX SZ-100S, manufactured by Titanium Industry Co., Ltd., mass ratio of zinc and silicon: 82 / 18, average particle size: 0.36 μm) was added and mixed (dry blended) at 0.50 parts by mass to obtain a water-absorbent resin composition (1).

  Water absorption capacity without pressure of the obtained water absorbent resin composition (1), water absorption capacity under pressure at 1.9 kPa, hydrogen sulfide deodorization ability test, ammonia deodorization ability test, deodorization test, separation rate, moisture absorption blocking The results of the rates are shown in Table 2, Table 3, and Table 4.

[Example 2]
Except for changing the water absorbent resin (1) obtained in Reference Example 1 to the water absorbent resin (2) obtained in Reference Example 2, the same operation as in Example 1 was carried out to obtain the water absorbent resin composition (2). Got. The water absorbent resin composition (2) was evaluated in the same manner as in Example 1, and the results are shown in Tables 2 and 3.

Example 3
A water absorbent resin composition (3) was obtained by performing the same operation as in Example 1 except that the water absorbent resin (1) obtained in Reference Example 1 was replaced with the water absorbent resin (3) obtained in Reference Example 3. Got. The water absorbent resin composition (3) was evaluated in the same manner as in Example 1, and the results are shown in Tables 2 and 3.

Example 4
A water absorbent resin composition (4) was obtained by performing the same operation as in Example 1 except that the water absorbent resin (1) obtained in Reference Example 1 was replaced with the water absorbent resin (4) obtained in Reference Example 4. Got. The water absorbent resin composition (4) was evaluated in the same manner as in Example 1, and the results are shown in Tables 2 and 3.

Example 5
A water absorbent resin composition (5) was obtained by performing the same operation as in Example 1 except that the water absorbent resin (1) obtained in Reference Example 1 was replaced with the water absorbent resin (5) obtained in Reference Example 5. Got. The water absorbent resin composition (5) was evaluated in the same manner as in Example 1, and the results are shown in Tables 2 and 3.

Example 6
The same procedure as in Example 1 was performed, except that the water absorbent resin (1) obtained in Reference Example 1 was replaced with the water absorbent resin (6) obtained in Reference Example 6, and the water absorbent resin composition (6) Got. The water absorbent resin composition (6) was evaluated in the same manner as in Example 1, and the results are shown in Tables 2 and 3.

Example 7
The water-absorbent resin (1) obtained in Reference Example 1 was changed to the water-absorbent resin (5) obtained in Reference Example 5, and a 15% by weight aqueous solution of a camellia plant leaf extract (product name: FS-80MO, Seller: Shiraimatsu Shinyaku Co., Ltd. (Location: 37-1 Ukawa, Mizuguchi-cho, Koka-gun, Shiga)) was added and mixed in the same manner as in Example 1 to absorb water. Resin composition (7) was obtained. The water absorbent resin composition (7) was evaluated in the same manner as in Example 1, and the results are shown in Tables 2 and 3.

Example 8
Hydrous composite oxide of zinc and silicon, a composite hydrous oxide of zinc and silicon obtained in Reference Example 10 (B1) (mass ratio of zinc and silicon: 85/15) was replaced in the same manner as in Example 1 The water-absorbent resin composition (8) was obtained. The water absorbent resin composition (8) was evaluated in the same manner as in Example 1, and the results are shown in Table 2, Table 3, and Table 4.

Example 9
Hydrous composite oxide of zinc and silicon, a composite hydrous oxide of zinc and aluminum obtained in Reference Example 11 (B2) (zinc and aluminum weight ratio: 85/15) was replaced in the same manner as in Example 1 The water absorbent resin composition (9) was obtained. The water-absorbent resin composition (9) was evaluated in the same manner as in Example 1, and the results are shown in Table 2, Table 3, and Table 4.

Example 10
Except having changed the addition amount of the composite hydrous oxide of zinc and silicon into 0.10 mass part, operation similar to Example 1 was performed and the water absorbing resin composition (10) was obtained. The water absorbent resin composition (10) was evaluated in the same manner as in Example 1, and the results are shown in Table 2, Table 3, and Table 4.

Example 11
The same procedure as in Example 1 was conducted, except that the water absorbent resin (1) obtained in Reference Example 1 was replaced with the water absorbent resin (10) obtained in Reference Example 13, and the water absorbent resin composition (11) was obtained. Got. The water absorbent resin composition (11) was evaluated in the same manner as in Example 1, and the results are shown in Tables 2 and 3.

[Comparative Example 1]
The same operation as in Example 1 was performed except that the water absorbent resin (1) obtained in Reference Example 1 was changed to the water absorbent resin (7) obtained in Reference Example 7, and a comparative water absorbent resin composition ( 1) was obtained. The comparative water-absorbent resin composition (1) was evaluated in the same manner as in Example 1, and the results are shown in Tables 2 and 3.

[Comparative Example 2]
The same operation as in Example 1 was performed except that the water absorbent resin (1) obtained in Reference Example 1 was changed to the water absorbent resin (8) obtained in Reference Example 8, and a comparative water absorbent resin composition ( 2) was obtained. The comparative water absorbent resin composition (2) was evaluated in the same manner as in Example 1, and the results are shown in Tables 2 and 3.

[Comparative Example 3]
The same procedure as in Example 1 was performed except that the water absorbent resin (1) obtained in Reference Example 1 was changed to the water absorbent resin (9) obtained in Reference Example 9, and a comparative water absorbent resin composition ( 3) was obtained. The comparative water-absorbent resin composition (3) was evaluated in the same manner as in Example 1, and the results are shown in Tables 2 and 3.

[Comparative Example 4]
A comparative water absorbent resin composition (4) was obtained in the same manner as in Example 1 except that the composite hydrous oxide of zinc and silicon was not added. The comparative water-absorbent resin composition (4) was evaluated in the same manner as in Example 1, and the results are shown in Table 2, Table 3, and Table 4.

[Comparative Example 5]
A composite hydrous oxide of zinc and silicon is mixed with a composite hydrous oxide having different zinc and silicon mass ratios and particle sizes (content mass ratio of zinc and silicon: 40/60, particle size: 250 μm or less, trade name: A comparative water-absorbent resin composition (5) was obtained by performing the same operation as in Example 1 except that it was changed to Shukurenzu KD-211S (manufactured by Rasa Industrial Co., Ltd.). The comparative water absorbent resin composition (5) was evaluated in the same manner as in Example 1, and the results are shown in Table 2, Table 3, and Table 4.

[Comparative Example 6]
A composite hydrous oxide of zinc and silicon is mixed with a composite hydrous oxide having different zinc and silicon content and particle sizes (content ratio of zinc and silicon: 40/60, particle size: 1 μm or less, trade name: A comparative water-absorbent resin composition (6) was obtained by performing the same operation as in Example 1 except that it was changed to Shukurenzu KD-211G (manufactured by Rasa Industrial Co., Ltd.) The comparative water-absorbent resin composition (6) obtained was evaluated in the same manner as in Example 1, and the results are shown in Table 2, Table 3, and Table 4.

[Comparative Example 7]
A composite hydrous oxide of zinc and silicon and a composite hydrous oxide of titanium and zinc having different combinations of metal elements (mass ratio of titanium and zinc: 50/50, average particle size: 0.50 μm, trade name: A comparative water-absorbent resin composition (7) was obtained by performing the same operation as in Example 1 except that CERATIOX TZ-100 (manufactured by Titanium Industry Co., Ltd.) was used. The comparative water-absorbent resin composition (7) was evaluated in the same manner as in Example 1, and the results are shown in Table 2, Table 3, and Table 4.

[Comparative Example 8]
A comparative water-absorbent resin composition (8) was obtained by performing the same operation as in Example 1 except that the composite hydrous oxide of zinc and silicon was changed to basic zinc carbonate (manufactured by Wako Pure Chemical Industries, Ltd.) which is a zinc compound. ) The comparative water absorbent resin composition (8) was evaluated in the same manner as in Example 8, and the results are shown in Table 2, Table 3, and Table 4.

[Comparative Example 9]
The same operation as in Example 1 except that the composite hydrous oxide of zinc and silicon was changed to zinc oxide (trade name: NANOTEC ZnO, manufactured by CII Kasei Co., Ltd., average particle size: 31 nm). The comparative water-absorbent resin composition (9) was obtained. The comparative water absorbent resin composition (9) was evaluated in the same manner as in Example 1 and shown in Table 2, Table 3, and Table 4.

[Comparative Example 10]
The same as Example 1 except that the composite hydrous oxide of zinc and silicon was changed to silicon dioxide (trade name: NANOTEC SiO ₂ , manufactured by CI Kasei Co., Ltd., average particle size: 26 nm). The operation was performed to obtain a comparative water-absorbent resin composition (10). The comparative water-absorbing resin composition for comparison (11) thus obtained was evaluated in the same manner as in Example 1, and the results are shown in Table 2, Table 3, and Table 4.

[Comparative Example 11]
The same as Example 1 except that the composite hydrous oxide of zinc and silicon was changed to titanium dioxide (trade name: NANOTEC TiO ₂ , manufactured by CI Kasei Co., Ltd., average particle size: 30 nm), which is an oxide of titanium alone. The operation was performed to obtain a comparative water-absorbent resin composition (11). The comparative water-absorbent resin composition (11) was evaluated in the same manner as in Example 1, and the results are shown in Table 2, Table 3, and Table 4.

[Comparative Example 12]
A comparative water-absorbent resin composition was prepared in the same manner as in Example 1 except that the composite hydrous oxide of zinc and silicon was changed to the composite hydrous oxide of titanium and silicon (B3) obtained in Reference Example 12. (12) was obtained. The comparative water-absorbent resin composition (12) was evaluated in the same manner as in Example 1, and the results are shown in Table 2, Table 3, and Table 4.

[Comparative Example 13]
The same operation as in Example 1 except that the composite hydrated oxide of zinc and silicon was changed to a mixture of the zinc oxide and the silicon dioxide (a mixture of the zinc oxide and the silicon dioxide at a ratio of 1/1). The comparative water-absorbent resin composition (12) was obtained. The water absorption capacity under no pressure of the obtained comparative water absorbent resin composition (12) is the water absorption capacity under pressure at 1.9 kPa, the hydrogen sulfide deodorizing ability test, the ammonia deodorizing ability test, and the results of the deodorizing test. 2 and shown in Table 3.

Example 11
37 parts by mass of the water absorbent resin composition (1) obtained in Example 1 and 63 parts by mass of pulverized wood pulp were dry-mixed using a mixer. Next, the obtained mixture was formed into a web having a size of 130 mm × 400 mm by air-making on a wire screen formed to 400 mesh (mesh size: 38 μm) using a batch type air-making machine. . Further, this web was pressed at a pressure of 196.14 kPa for 5 seconds to obtain an absorbent having a basis weight of about 0.05 g / cm ² .

  Subsequently, a liquid-impermeable back sheet made of liquid-impermeable polypropylene, the absorbent body, and a non-woven fabric surface sheet made of liquid-permeable polypropylene are pasted together in this order using a double-sided tape. Thus, a pad type of an adult paper diaper, which is an absorbent article, was obtained. The mass of this absorbent article (1) was 50 g.

  Table 5 summarizes the deodorization test results of the absorbent article (1) obtained.

[Examples 12 to 14]
Absorbing by changing the water absorbent resin composition (1) used in Example 11 to the water absorbent resin compositions (8), (9) and (10) obtained in Examples 8, 9, and 10. Sexual articles (2), (3) and (4) were obtained, respectively.

  Table 5 summarizes the deodorization test results of the absorbent articles (2), (3), and (4) obtained.

[Comparative Examples 14-17]
The water-absorbent resin composition (1) used in Example 10 was compared with the comparative water-absorbent resin compositions (4), (5), (7), (13) obtained in Comparative Examples 4, 5, 7, and 13. ) To obtain comparative absorbent articles (1), (2), (3), and (4).

  The comparative absorbent articles (1), (2), (3), and (4) obtained deodorant test results are summarized in Table 5.

Example 15
For the water absorbent resin compositions (1), (8), (9) obtained in Examples 1, 8, and 9 and the comparative water absorbent resin composition (4) obtained in Comparative Example 4, (j) Urine resistance and durability were evaluated. As a result, Example 1: ○ (60 seconds or more), Example 8: ○ (60 seconds or more), Example 9: ○ (60 seconds or more), Comparative Example 4: × (10 seconds). It was.

Claims (10)

Water absorption comprising a water absorbent resin obtained by polymerizing and crosslinking a monomer component mainly composed of acrylic acid and / or a salt thereof, and a composite hydrous oxide containing zinc and silicon, or zinc and aluminum A resin composition comprising:
The composite hydrous oxide contains zinc as a main component of metal,
Mass ratio of the content and the silicon or the aluminum content of zinc is 70 / 30-95 / 5,
The content of the composite hydrous oxide is 0.001 to 5 parts by mass with respect to 100 parts by mass of the water absorbent resin,
And the water absorption resin composition whose water absorption capacity | capacitance under pressure (60 minute value) in 1.9 kPa with respect to 0.90 mass% sodium chloride aqueous solution of the said water absorbing resin composition is 20 g / g or more. The water-absorbent resin composition according to claim 1, wherein a mass ratio between the zinc content and the silicon or aluminum content is 82/18 to 95/5.   The composite hydrous oxide is obtained by a coprecipitation method in a solution containing a water-soluble zinc compound and a water-soluble silicon compound, or a solution containing a water-soluble zinc compound and a water-soluble aluminum compound. The water-absorbent resin composition described in 1.   The water-absorbent resin composition according to any one of claims 1 to 3, wherein a separation rate of the composite hydrous oxide from the water-absorbent resin in a swollen state is 20% or less.   The water-absorbent resin composition is in the form of particles, and particles having a particle size of 150 μm or more and less than 850 μm are 90% by mass or more of the whole, and particles of 300 μm or more are contained by 60% by mass or more of the whole. The water-absorbent resin composition according to any one of the above.   The water absorbent resin composition according to any one of claims 1 to 5, further comprising a plant component.   The absorber for sanitary materials containing the water absorbing resin composition of any one of Claims 1-6, and a hydrophilic fiber. A composite water-containing oxide containing a water-absorbent resin obtained by polymerizing and crosslinking a monomer component mainly composed of acrylic acid and / or a salt thereof , hydrophilic fiber, and zinc and silicon, or zinc and aluminum A sanitary material absorber comprising:
The composite hydrous oxide contains zinc as a main component of metal,
Mass ratio of the content and the silicon or the aluminum content of zinc is 70 / 30-95 / 5,
The content of the composite hydrous oxide is 0.001 to 5 parts by mass with respect to 100 parts by mass of the water absorbent resin,
And the absorber for sanitary materials characterized by the water absorption capacity | capacitance (60 minute value) under pressure in 1.9 kPa with respect to 0.90 mass% sodium chloride aqueous solution of the said water absorbing resin being 20 g / g or more.   An absorbent article comprising the absorbent body according to claim 7 or 8, a top sheet having liquid permeability, and a back sheet exhibiting liquid impermeability. By polymerizing and crosslinking a monomer component mainly composed of acrylic acid and / or a salt thereof, the water absorption capacity under load at 1.9 kPa (60 minutes value) with respect to a 0.90% by mass sodium chloride aqueous solution is 20 g / obtaining a water-absorbent resin that is greater than or equal to g,
Zinc and silicon having a mass ratio of zinc content to silicon or aluminum content of 70/30 to 95/5 or a composite hydrous oxide containing zinc and aluminum is added to the water absorbent resin. A step of adding 0.001 to 5 parts by mass and mixing with respect to 100 parts by mass of the conductive resin,
A method for producing a water absorbent resin composition.