JP5784282B2 - Absorbent resin particles, absorbent body and absorbent article using the same - Google Patents

Description

  The present invention relates to water-absorbing resin particles, an absorbent body using the same, and an absorbent article.

  Absorbent resin particles have been widely used mainly in sanitary products because of their ability to absorb liquids several tens to several hundred times their own weight. However, although the absorbent resin particles absorb and retain liquids such as urine and menstrual blood, they themselves have almost no deodorizing function. Liquids such as urine, blood, and body fluids have unique unpleasant odors, and are easily perished by air and / or bacteria, and they emit bad odors due to spoilage, thus satisfying both absorption performance and deodorization performance. There has been a demand for the appearance of materials. As a method of satisfying both, a mixture of powders of water-absorbent resin and zeolite (Patent Documents 1 to 3), a composition in which activated carbon is coated with a water-absorbent resin (Patent Document 4), a water-absorbent resin and an antibacterial agent (Patent Document 5), a water-absorbing material (Patent Document 6) obtained by mixing and polymerizing a zeolite slurry in a polymerization solution, and spraying the solution onto a nonwoven fabric and drying (Patent Document 6), absorbent resin particles A deodorant resin composition (Patent Document 7) in which zeolite powder is dispersed inside has been proposed.

JP-A-57-25813 JP 59-179114 A JP 59-189854 A JP-A-56-31425 Japanese Patent Publication No. 3-14867 JP-A-2-84957 JP-A-8-176338

  However, when the above water-absorbing resin (composition), water-absorbing material or deodorant resin composition is used, malodor can be reduced, but it has a deodorizing effect against the malodor of the first urination. Only. When an absorbent article is used, it is rarely changed immediately after a single urination, and is often changed after a plurality of urinations. Therefore, the deodorizing effect of conventional deodorant absorbent resins is insufficient.

  As a result of intensive studies in view of the above problems, the present inventors have reached the present invention.

Absorption water absorbent resin particles of the present invention, the water-soluble vinyl monomer (a1) and / or a hydrolyzable vinyl monomer (a2) as well as crosslinked polymer to crosslinking agent (b) essential constituent unit (A) and complex silicates an absorption water absorbent resin particles which comprises a deodorizing substance (C) which is a metal salt, in the interior of the intake water resin particles (C) relative to the weight of (a) 0.01 to 5 The gist is that it is present at 0.0% by weight.

  When applied to absorbent articles such as diapers, napkins, and pet sheets, the absorbent resin particles of the present invention can exhibit deodorant properties that are the same as the first after urination multiple times. Therefore, the absorbent body or absorbent article using the absorbent resin particles of the present invention can suppress the generation of bad odor even when urinated multiple times and used for a long time, and can significantly reduce discomfort to the wearer and the surrounding people. .

  The water-soluble vinyl monomer (a1) is not particularly limited and is known {for example, a vinyl monomer disclosed in Japanese Patent No. 3648553, Japanese Patent Laid-Open No. 2003-165883, Japanese Patent Laid-Open No. 2005-75982, Japanese Patent Laid-Open No. 2005-95759}. Etc. can be used.

  The hydrolyzable vinyl monomer (a2) means a vinyl monomer that becomes a water-soluble vinyl monomer (a1) by hydrolysis, and is not particularly limited (for example, Japanese Patent No. 3648553, JP-A No. 2003-165883, The vinyl monomer etc. of Unexamined-Japanese-Patent No. 2005-75982, Unexamined-Japanese-Patent No. 2005-95759} etc. can be used. The water-soluble vinyl monomer means a vinyl monomer having a property of dissolving at least 100 g in 100 g of water at 25 ° C. The term “hydrolyzable” refers to the property of being hydrolyzed by the action of 50 ° C. water and, if necessary, the catalyst (acid or base) to make it water-soluble. Hydrolysis of the hydrolyzable vinyl monomer may be performed either during polymerization, after polymerization, or both of them, but from the viewpoint of the molecular weight of the resulting absorbent resin particles, etc., is preferable.

  Of these, water-soluble vinyl monomers (a1) are preferred from the viewpoint of absorption characteristics, etc., more preferably anionic vinyl monomers, and more preferably carboxy (salt) groups, sulfo (salt) groups, amino groups, carbamoyl groups. Vinyl monomers having an ammonio group or a mono-, di- or tri-alkyl ammonio group, then preferably vinyl monomers having a carboxy (salt) group or a carbamoyl group, particularly preferably (meth) acrylic acid (salt) and (Meth) acrylamide, next particularly preferably (meth) acrylic acid (salt), most preferably acrylic acid (salt).

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

  When either the water-soluble vinyl monomer (a1) or the hydrolyzable vinyl monomer (a2) is used as a structural unit, each may be used alone as a structural unit, or two or more kinds may be used as a structural unit if necessary. The same applies when the water-soluble vinyl monomer (a1) and the hydrolyzable vinyl monomer (a2) are used as constituent units. Further, when the water-soluble vinyl monomer (a1) and the hydrolyzable vinyl monomer (a2) are used as structural units, the content molar ratio (a1 / a2) is preferably 75/25 to 99/1, more preferably. 85/15 to 95/5, particularly preferably 90/10 to 93/7, and most preferably 91/9 to 92/8. Within this range, the absorption performance is further improved.

There are no particular limitations on the crosslinking agent (b), and known crosslinking agents such as those disclosed in known {eg, Japanese Patent No. 3648553, Japanese Patent Laid-Open No. 2003-165883, Japanese Patent Laid-Open No. 2005-75982, Japanese Patent Laid-Open No. 2005-95759}, and the like. Can be used.
Among these, from the viewpoint of absorption characteristics, etc., a crosslinking agent having two or more ethylenically unsaturated groups is preferable, more preferably a poly (meth) allyl ether of a polyol having 2 to 10 carbon atoms, particularly preferably triallylsia. Nurate, triallyl isocyanurate, tetraallyloxyethane and pentaerythritol triallyl ether, most preferably pentaerythritol triallyl ether.

  The content (mol%) of the crosslinking agent (b) unit is preferably 0.001 to 5, more preferably, based on the number of moles of the water-soluble vinyl monomer (a1) unit and the hydrolyzable vinyl monomer (a2) unit. Is 0.005 to 3, particularly preferably 0.01 to 1. Within this range, the absorption characteristics are further improved.

  In addition to these, monomers having water-soluble vinyl monomer (a1) and / or hydrolyzable vinyl monomer (a2) and crosslinking agent (b) as essential constituent monomers are copolymerizable with these. Of vinyl monomer (a3)

  Other vinyl monomers (a3) that can be copolymerized are not particularly limited and are known {for example, the hydrophobicity of Japanese Patent No. 3648553, JP-A No. 2003-165883, JP-A No. 2005-75982, JP-A No. 2005-95759} Vinyl monomers can be used.

  When the other vinyl monomer (a3) is included, the amount (mol%) of the other vinyl monomer (a3) used is based on the number of moles of the water-soluble vinyl monomer (a1) and the hydrolyzable vinyl monomer (a2). 0.01-5 is preferable, More preferably, it is 0.05-3, Next, Preferably it is 0.08-2, Most preferably, it is 0.1-1.5. From the viewpoint of absorption performance and the like, it is most preferable not to use other vinyl monomers (a3).

  As a method for obtaining a crosslinked polymer (A) by copolymerizing a water-soluble vinyl monomer (a1) and / or a hydrolyzable vinyl monomer (a2) and a monomer having a crosslinking agent (b) as an essential constituent monomer. Are known aqueous solution polymerization {adiabatic polymerization, thin film polymerization, spray polymerization method, etc .; JP-A-55-133413, etc.] and known reverse phase suspension polymerization {JP-B-54-30710, JP-A-56-26909. No. 1 and Japanese Patent Laid-Open No. 1-5808 etc.}.

  A hydrogel obtained by polymerization {consisting of a crosslinked polymer (A) and water. } Can be shredded as necessary. When chopping, the size (longest diameter) of the gel after chopping is preferably 50 μm to 10 cm, more preferably 100 μm to 2 cm, and particularly preferably 1 mm to 1 cm.

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

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

  Examples of the deodorant substance (C) include zeolite, activated carbon, flavonoid compound, cyclodextrin, complex metal silicate, and the like.

As the zeolite, both natural and synthetic zeolites can be used. Zeolite has a three-dimensional framework structure and is represented by the general formula M _{2 / n} 0 ·· Na ₂ O · Al ₂ O ₃ · 2.5SiO ₂ · xH ₂ O (wherein x is the crystal water). An integer representing a number, where M is a cation and n is the valence of the cation). Examples of the cation include alkali metal (sodium ion, potassium ion), alkaline earth metal (calcium ion, magnesium ion), ammonium ion and the like.

  Flavonoid compounds are substances extracted from plants such as rice, pine, hinoki and cocoons, and commercially available products include “Fresh Reimatsu” (manufactured by Shiraimatsu Shinyaku Co., Ltd.), “Smeral” (manufactured by Environmental Science Development Co., Ltd.), etc. Is mentioned.

  Examples of the cyclodextrin include α- or β-cyclodextrin, hydroxymethylcyclodextrin, hydroxyethylcyclodextrin, hydroxypropylcyclodextrin, and hydroxybutylcyclodextrin.

The composite silicate metal salt is a silicate metal salt or an aluminosilicate metal salt composed of silica, alumina and a metal oxide, and is SiO ₂ · MO _{n / 2} or SiO ₂ · MO _{n / 2} · Al ₂ O. ₃ (M represents at least one metal selected from the group consisting of zinc, copper, silver, cobalt, nickel, iron, titanium, barium, tin, magnesium, and zirconium, and n represents the valence of the metal). It is done.

  A commercial product can be used as the composite silicate metal salt used as the deodorant substance. Examples of commercially available composite metal silicates include sepiolite (manufactured by Enomoto Kasei Co., Ltd.), Mizukanite (manufactured by Mizusawa Chemical Industry Co., Ltd.), shoe cleanse (manufactured by Rasa Industries Co., Ltd.), and the like.

  Of the deodorant substance (C), from the viewpoint of deodorization and absorption performance, it is preferably a composite metal silicate, and particularly preferably Mizkanite.

  The deodorant substance (C) is present in the absorbent resin particles of the present invention in an amount of 0.01 to 5.0% by weight based on the weight of the crosslinked polymer (A). The amount present in the interior is preferably 0.01 to 3.0% by weight, more preferably 0.05 to 2.0% by weight, from the viewpoint of deodorizing performance when used multiple times. When the amount of (C) present in the absorbent resin particles is less than 0.01% by weight, the deodorizing performance is deteriorated, and when it exceeds 5.0% by weight, the absorption performance is deteriorated.

In addition, content inside the absorptive resin particle of the deodorant substance (C) mentioned above is measured by the following method.
<Measurement method for content (% by weight) of deodorant substance present in absorbent resin particles>
In a glass beaker, 1 part by weight of absorbent resin particles and 100 parts by weight of methanol are added and stirred at room temperature for 10 minutes at 600 rpm. Immediately after completion of the stirring, the supernatant methanol is transferred to another container by decantation. 100 parts by weight of methanol is again added to the beaker, and the same operation is performed four more times. The obtained supernatant methanol is collected in an eggplant flask weighed in advance, and the methanol is evaporated at 40 ° C. using an evaporator, and then weighed. By subtracting the weight of the eggplant flask weighed in advance from the weight after evaporation of methanol, the weight part of the evaporated and dried product is obtained. The content (% by weight) of the deodorant substance present inside the absorbent resin particles is a value obtained by subtracting 100 times the weight of the evaporated and dried product from the charged% of the deodorant substance.

  The shape of the deodorant substance (C) is preferably particulate from the viewpoint of deodorizing performance. The weight average particle diameter of the deodorant substance (C) is preferably from 0.01 to 100 μm, more preferably from 0.05 to 50 μm, still more preferably from the viewpoint of workability and deodorizing performance during production. 10 μm.

The absorbent resin particles of the present invention can further contain an inorganic powder (D), and are preferably contained on the surface of the absorbent resin particles. The inorganic powder (D) includes hydrophilic inorganic particles (d1) and hydrophobic inorganic particles (d2).
Examples of the hydrophilic inorganic particles (d1) include particles such as glass, silica gel, silica, and clay.
Examples of the hydrophobic inorganic particles (d2) include particles of carbon fiber, kaolin, talc, shirasu and the like.
Of these, hydrophilic inorganic particles (d1) are preferred, and silica is most preferred.

  The shape of the hydrophilic inorganic particles (d1) and the hydrophobic inorganic particles (d2) may be any of an irregular shape (crushed shape), a true spherical shape, a film shape, a rod shape, a fiber shape, and the like. An indefinite shape (crushed shape) and a true spherical shape are preferable, and a true spherical shape is more preferable.

  The content (% by weight) of the inorganic powder (D) of the absorbent resin particles is preferably 0.01 to 3.0, more preferably based on the weight of the crosslinked polymer (A) from the viewpoint of absorption performance. 0.05 to 1.0, then preferably 0.1 to 0.8, particularly preferably 0.2 to 0.7, most preferably 0.3 to 0.6. Within this range, the absorption performance is further improved. In particular, the content (% by weight) of the inorganic powder (D) present on the surface of the absorbent resin particles is preferably within this range.

  The absorbent resin particles of the present invention may contain other additives (for example, known preservatives, fungicides, antibacterial agents, antioxidants, ultraviolet rays (for example, JP 2003-225565 A, JP 2006-131767 A). An absorbent, a colorant, a fragrance, a deodorant, an organic fibrous material, etc.}. When these additives are contained, the content (% by weight) of the additive is preferably 0.001 to 10, more preferably 0.01 to 5, particularly preferably based on the weight of the crosslinked polymer (A). Preferably it is 0.05 to 1, most preferably 0.1 to 0.5.

  100-800 are preferable, as for the weight average particle diameter (micrometer) of the absorptive resin particle | grains of this invention, More preferably, it is 200-500, Most preferably, it is 300-400. Within this range, the absorption performance is further improved.

  The smaller the content of fine particles, the better the absorption performance. Therefore, the content of fine particles of 106 μm or less (preferably 150 μm or less) in all particles is preferably 3% by weight or less, more preferably 1% by weight or less. .

In addition, the weight average particle size is obtained by measuring the particle size distribution of the measurement sample, and the logarithmic probability paper {horizontal axis: particle size, vertical axis: cumulative content (% by weight)} has a relationship between the cumulative content and the particle size. It is obtained by plotting and determining the particle size corresponding to a cumulative content of 50% by weight. The particle size distribution is measured in accordance with JIS Z8815-1994. For example, sieves having an inner diameter of 150 mm and a depth of 45 mm {openings: 710 μm, 500 μm, 300 μm, 150 μm, and 106 μm} are used with a narrow opening sieve. Overlay, put 50 g of measurement sample on top of 710 μm sieve with widest opening, sieve for 10 minutes with sieve shaker, measure weight of measurement sample remaining on each sieve, It is measured by determining the weight percent of the measurement sample remaining on each sieve based on the weight of the measurement sample.
The content of the fine particles can be determined using a plot created when determining the weight average particle diameter.

  The apparent density (g / ml) of the absorbent resin particles of the present invention is preferably 0.54 to 0.70, more preferably 0.56 to 0.65, and particularly preferably 0.58 to 0.50 from the viewpoint of absorption performance. 0.60.

  The shape of the absorbent resin particle of the present invention is not particularly limited, and examples thereof include an irregular crushed shape, a flake shape, a pearl shape, and a rice grain shape. Among these, when applied to paper diapers and the like, from the viewpoint of good entanglement with the fibrous material, no fear of falling off from the fibrous material, and from the viewpoint of absorption performance, the irregularly crushed shape and the pearl shape are preferable, A regular crushed shape is particularly preferred.

  The absorbent resin particles of the present invention can be preferably produced by the following production method. That is, in the above-mentioned production method of the crosslinked polymer (A), the water-soluble vinyl monomer (a1) and / or the hydrolyzable vinyl monomer (a2) and the crosslinking agent (a3) are used as the essential constituent monomer (a). After the monomer is copolymerized to obtain a crosslinked polymer (A), (A) and the deodorant substance (C) are mixed to obtain a crosslinked polymer (A) / deodorant substance composite gel. A method for producing absorbent resin particles comprising the step (1) of obtaining, and containing (C) in an amount of 0.01 to 5.0% by weight based on the weight of the crosslinked polymer (A) inside the absorbent resin particles. preferable.

<About step (1)>
As a method of mixing the cross-linked polymer (A) and the deodorant substance (C), (1) a water-containing gel composed of the cross-linked polymer (A) and water and the deodorant substance (C) are mixed. Method: (2) A method of mixing the crosslinked polymer (A) (dry particles) and the deodorant substance (B) is included. Among these, the method (1) is preferable from the viewpoint of absorption performance and the like.

  The mixing temperature (° C.) of the crosslinked polymer (A) and the deodorant substance (C) is preferably from 30 to 150, more preferably from 40 to 120, particularly preferably from 50 to 100. Within this range, it becomes easier to mix evenly, and the absorption performance is further improved.

  As a mixing apparatus of the cross-linked polymer (A) and the deodorant substance (C), a known apparatus {double-arm kneader, internal mixer (Banbury mixer), self-cleaning mixer, gear compounder, screw type extrusion Machine, screw-type kneader, minced machine, turbulizer, cylindrical mixer, V-shaped mixer, ribbon-type mixer, screw-type mixer, double-armed mixer, grinding-type kneader, groove-type mixer, cocoon Type mixer etc.} can be used. These can be used in combination.

  In the step (1), the weight average particle diameter of the deodorant substance (C) before mixing is preferably in the same range as the weight average particle diameter described above, and the deodorant substance (C before mixing) Similarly, the above-mentioned property is preferable.

The crosslinked polymer (A) / deodorant substance composite gel obtained in the step (1) can be led to the absorbent resin particles by post-treatment.
Post-processing includes shredding, solvent evaporation (drying), pulverization, particle size adjustment, surface crosslinking, and mixing of additives. These post-processing may be performed in combination, or only one of them may be performed. Moreover, there is no restriction | limiting in the order of post-processing, Although it determines suitably, said order is preferable. Of these post-treatments, it is preferable to include drying. Moreover, when employ | adopting aqueous solution polymerization, it is preferable that a grinding | pulverization is included further.

<Shred>
Shredding can be performed by a known method, and can be shredded using a known shredding device {for example, a bex mill, rubber chopper, pharma mill, mincing machine, impact crusher and roll crusher}. .

  When shredding, the size (longest diameter) of the composite gel after shredding is preferably 50 μm to 10 cm, more preferably 100 μm to 2 cm, and particularly preferably 1 mm to 1 cm. Within this range, in addition to being easier to handle, when the solvent is subsequently distilled off, the solvent is further easily distilled off, and when pulverizing thereafter, the pulverization is further facilitated.

<Solvent evaporation (drying)>
In the polymerization step for producing the crosslinked polymer (A), when a solvent (such as an organic solvent and water) is used, the solvent is preferably distilled off.
When the solvent contains an organic solvent, the content (% by weight) of the organic solvent after distillation is preferably 10 to 0.01, more preferably 5 to 0.05, based on the weight of the absorbent resin particles. Particularly preferred is 3 to 0.1, and most preferred is 1 to 0.5. Within this range, the absorption performance is further improved.

  When water is contained in the solvent, the water content (% by weight) after distillation is preferably 0 to 20, more preferably 0 to 10, particularly preferably 0 to 7, most preferably based on the weight of the absorbent resin particles. Is 0-3. Within this range, the absorption performance and handling properties after drying (powder fluidity of the absorbent resin particles, etc.) are further improved.

  In addition, the content and moisture of the organic solvent are an infrared moisture measuring device {JE400 manufactured by Kett Science Laboratory Co., Ltd .: 120 ± 5 ° C., 30 minutes, atmospheric humidity before heating 50 ± 10% RH, lamp specification 100V, It is calculated | required from the weight loss of the measurement sample before and behind heating when heated by 40W}.

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

<Crushing>
The pulverization is preferably performed after the solvent is distilled off.
The pulverization method is not particularly limited, and can be pulverized by a known pulverizer (for example, a hammer-type pulverizer, an impact-type pulverizer, a roll-type pulverizer, and a shet airflow-type pulverizer).

<Granularity control>
The size of the pulverized particles is adjusted by sieving or the like as necessary.

<Surface cross-linking>
The cut chopped gel or the pulverized particles can be subjected to surface cross-linking treatment with a surface cross-linking agent, if necessary.
As the surface crosslinking agent, known {for example, JP 59-189103, JP 58-180233, JP 61-16903, JP 61-2111305, JP 61-252212, Surface cross-linking agents {polyvalent glycidyl, polyhydric alcohol, polyvalent amine, polyvalent aziridine, polyvalent isocyanate, silane coupling agent and polyvalent metal of JP-A-51-136588 and JP-A-61-257235} Etc.} can be used. Of these surface cross-linking agents, from the viewpoint of economy and absorption performance, polyvalent glycidyl, polyhydric alcohol and polyvalent amine are preferable, more preferably polyvalent glycidyl and polyhydric alcohol, particularly preferably polyvalent glycidyl, Preferred is ethylene glycol diglycidyl ether.

  In the case of surface cross-linking, the amount (% by weight) of the surface cross-linking agent is not particularly limited because it can be changed variously depending on the type of surface cross-linking agent, cross-linking conditions, target performance, etc. From a viewpoint etc., based on the weight of an essential constituent monomer (a), 0.001-3 are preferable, More preferably, it is 0.005-2, Most preferably, it is 0.01-1.

  In the case of surface crosslinking, a known method {for example, Japanese Patent No. 3648553, Japanese Patent Laid-Open No. 2003-165883, Japanese Patent Laid-Open No. 2005-75982, Japanese Patent Laid-Open No. 2005-95759} can be applied.

<Mixing of additives>
For shredded gels, dry particles, pulverized particles or surface cross-linked particles, other additives (for example, known preservatives, fungicides, antibacterial agents (for example, Japanese Patent Application Laid-Open Nos. 2003-225565 and 2006-131767) Agent, antioxidant, ultraviolet absorber, colorant, fragrance, deodorant, inorganic powder, organic fibrous material, etc.}.
When other additives are mixed, the mixing method is not limited as long as uniform mixing is possible, and a known mixing method can be applied.

  The absorbent resin particles of the present invention can be used as an absorbent body together with a fibrous material. The structure and manufacturing method of the absorber are the same as those known in the art (Japanese Patent Laid-Open Nos. 2003-225565, 2006-131767, and 2005-097569, etc.). Moreover, it is preferable that this absorber comprises absorbent articles {paper diapers, sanitary napkins, etc.}. The manufacturing method and the like of the absorbent article are the same as known ones (Japanese Unexamined Patent Publication Nos. 2003-225565, 2006-131767, and 2005-097569, etc.).

  When the absorbent resin particle of the present invention is used as an absorbent body together with a fibrous material, the weight ratio of the absorbent resin particle to the fiber (weight of absorbent resin particle / weight of fiber) is preferably 40/60 to 70/30, More preferably, it is 50 / 50-60 / 40.

<Production Example 1>
108.5 parts (1.51 mol) of acrylic acid (a1-1) as a water-soluble vinyl monomer, 0.35 parts (0.0014 mol) of pentaerythritol triallyl ether (b1) as a crosslinking agent and deionized water 389.9 parts were kept at 3 ° C. with stirring and mixing. Nitrogen was introduced into the mixture to bring the dissolved oxygen amount to 1 ppm or less, and then 0.43 parts of a 1% by weight aqueous hydrogen peroxide solution and 0.81 part of a 2% by weight ascorbic acid aqueous solution were added and mixed to initiate polymerization. I let you. After the temperature of the mixture reached 60 ° C., polymerization was performed at 60 ± 2 ° C. for about 8 hours to obtain a crosslinked polymer (A1) hydrogel (G1).

<Production Example 2>
29.9 parts (0.41 mole) of acrylic acid (a1-1) as water-soluble vinyl monomer, 100.3 parts (1.07 mole) of sodium acrylate (a1-2), ethylene glycol di Glycidyl ether (b2) 0.23 part (0.00134 mol part) and deionized water 492.2 parts were kept at 3 ° C. with stirring and mixing. Nitrogen gas is allowed to flow into this mixture so that the amount of dissolved oxygen in the mixture is 1 ppm or less, and then 0.43 part of a 1% by weight aqueous hydrogen peroxide solution and 0.80 part of a 2% by weight ascorbic acid aqueous solution are added and mixed. The polymerization was started. After the temperature of the mixture reached 60 ° C., polymerization was performed at 60 ± 2 ° C. for about 8 hours to obtain a crosslinked polymer (A2) hydrogel (G2).

<Example 1>
While chopping 400 parts of the crosslinked polymer hydrogel (G1) obtained in Production Example 1 with a mincing machine (12VR-400K manufactured by ROYAL), add 99.2 parts of a 35 wt% aqueous sodium hydroxide solution and mix. Neutralized and subsequently added 1.06 part of {"Mizukanite AP" (manufactured by Mizusawa Chemical Co., Ltd.)} (C1) as a deodorant substance to obtain a chopped gel. Further, the chopped gel was dried with a ventilation band dryer {90 ° C., wind speed 2 m / sec} to obtain a dried product. The dried product was pulverized with a juicer mixer (Osterizer BLENDER manufactured by Oster), and then sieved to adjust the particle size to a particle size range of 710 to 150 μm to obtain pulverized particles. Subsequently, 100 parts of the pulverized particles were stirred at high speed (high-speed stirring turbulizer manufactured by Hosokawa Micron Co., Ltd .: rotation speed: 2000 rpm), and the surface cross-linking agent {water / methanol containing ethylene glycol diglycidyl ether at a concentration of 9% by weight> After adding 5.5 parts of mixed solution (water / methanol = 70/30; weight ratio) and mixing uniformly, it left still at 90 degreeC for 45 minutes, and obtained the absorbent resin particle (1) of this invention. It was.

<Example 2>
The same as Example 1 except that “{“ Mizukanite AP ”(manufactured by Mizusawa Chemical Co., Ltd.)} (C1)” was changed to “{“ Mizukanite HP ”(manufactured by Mizusawa Chemical Industry Co., Ltd.)} (C2)”. Thus, the absorbent resin particles (2) of the present invention were obtained.

<Example 3>
Except that “{“ Mizukanite AP ”(manufactured by Mizusawa Chemical Co., Ltd.)} (C1)” was changed to “{Sepiolite“ PANSIL ”(manufactured by Enomoto Kasei)} (C3)”, in the same manner as in Example 1, Absorbent resin particles (3) of the present invention were obtained.

<Example 4>
Same as Example 1 except that “{“ Mizukanite AP ”(manufactured by Mizusawa Chemical Co., Ltd.)} (C1)” is changed to “{“ Shukurenzu KD-311 ”(manufactured by Lhasa Kogyo)} (C4)”. Thus, the absorbent resin particles (4) of the present invention were obtained.

<Example 5>
Absorbent resin particles (5) of the present invention were obtained in the same manner as in Example 2, except that “(C2) 1.06 part” was changed to “(C2) 0.01 part”.

<Example 6>
Absorbent resin particles (6) of the present invention were obtained in the same manner as in Example 2, except that “(C2) 1.06 parts” was changed to “(C2) 5.30 parts”.

<Example 7>
Add {6 Mizukanite AP] (manufactured by Mizusawa Chemical Co., Ltd.)} (C1) 1.06 parts as a deodorant substance (C) to 400 parts of the crosslinked polymer hydrogel (G2) obtained in Production Example 2, and mince A chopped gel was obtained by mixing with a machine (12VR-400K manufactured by ROYAL). Further, the chopped gel was dried with a ventilation band dryer {90 ° C., wind speed 2 m / sec} to obtain a dried product. The dried product was pulverized with a juicer mixer (Osterizer BLENDER manufactured by Oster), and then sieved to adjust the particle size to a particle size range of 710 to 150 μm to obtain pulverized particles. Subsequently, 100 parts of the pulverized particles were stirred at high speed (high-speed stirring turbulizer manufactured by Hosokawa Micron Co., Ltd .: rotation speed: 2000 rpm), and the surface cross-linking agent {water / methanol containing ethylene glycol diglycidyl ether at a concentration of 9% by weight> After adding 5.5 parts of mixed solution (water / methanol = 70/30; weight ratio) and mixing uniformly, it left still at 90 degreeC for 45 minutes, and obtained the absorbent resin particle (7) of this invention. It was.

<Comparative Example 1>
While chopping 400 parts of the crosslinked polymer hydrogel (G1) obtained in Production Example 1 with a mincing machine (12VR-400K manufactured by ROYAL), add 99.2 parts of a 35 wt% aqueous sodium hydroxide solution and mix. Neutralized to obtain a chopped gel. Further, the chopped gel was dried with a ventilation band dryer {90 ° C., wind speed 2 m / sec} to obtain a dried product. The dried product was pulverized with a juicer mixer (Osterizer BLENDER manufactured by Oster), and then sieved to adjust the particle size to a particle size range of 710 to 150 μm to obtain pulverized particles. Subsequently, 100 parts of the pulverized particles were stirred at a high speed (high-speed stirring turbulizer manufactured by Hosokawa Micron Co., Ltd .: rotation speed: 2000 rpm). 5.5 parts of a mixed solution (water / methanol = 70/30; weight ratio)} was added, mixed uniformly, and then allowed to stand at 90 ° C. for 45 minutes to obtain comparative absorbent resin particles (H1). It was.

<Comparative Example 2>
400 parts of the crosslinked polymer hydrogel (G2) obtained in Production Example 2 was dried with a ventilation band dryer {90 ° C., wind speed 2 m / sec} to obtain a dried product. The dried product was pulverized with a juicer mixer (Osterizer BLENDER manufactured by Oster), and then sieved to adjust the particle size to a particle size range of 710 to 150 μm to obtain pulverized particles. Subsequently, 100 parts of the pulverized particles were stirred at high speed (high-speed stirring turbulizer manufactured by Hosokawa Micron Co., Ltd .: rotation speed: 2000 rpm), and the surface cross-linking agent {water / methanol containing ethylene glycol diglycidyl ether at a concentration of 9% by weight> Mixed solution (water / methanol = 70/30; weight ratio)} 5.5 parts was added and mixed uniformly, and then allowed to stand at 90 ° C. for 45 minutes to obtain comparative absorbent resin particles (H2). It was.

<Comparative Example 3>
Absorbent resin particles (H3) for comparison were obtained by powder mixing 100 parts of the absorbent resin particles (H1) obtained in Comparative Example 1 and 1 part of “Mizkanite HP” (C2).

<Comparative Example 4>
Absorbent resin particles (H4) for comparison were obtained in the same manner as in Example 2, except that “(C2) 1.06 part” was changed to “(C2) 0.005 part”.

<Comparative Example 5>
Comparative absorbent resin particles (H5) were obtained in the same manner as in Example 2, except that “(C2) 1.06 parts” was changed to “(C2) 10.60 parts”.

The following method evaluated the deodorizing property at the time of multiple use of an absorbent resin particle.
<Deodorization test when used multiple times>
In a 100 cc sealed container, 1.0 g of absorbent resin particles and 15 ml of adult fresh urine are absorbed and sealed, and then stored in a thermostat set at 40 ° C. for 1 hour. Thereafter, the container lid is opened in the odorless room, the odor is sniffed, and the first odor intensity is evaluated. After the evaluation, the container is left open for 1 hour with the lid open, and again 15 ml of adult fresh urine is added and absorbed. The same operation as the first time is performed, and the second odor intensity is evaluated. This operation is repeated once, and the odor intensity is evaluated three times in total. The odor intensity was evaluated in the following 6 stages, and the evaluation was performed by 10 panelists whose odor determination ability was confirmed by the T & T olfactometer method, and the average value of 10 persons was obtained.

0: Odorless 1: Odor that can be finally detected (Sensitive Iki Value Concentration)
2: Weak odor that understands what kind of odor (recognized Iki value concentration)
3: Smell that can be easily detected 4: Strong smell 5: Strong smell

  As can be seen from Table 1, it can be seen that the absorbent resin particles obtained in Examples 1 to 7 are excellent in deodorizing properties even when used multiple times. On the other hand, the absorbent resin particles obtained in Comparative Examples 1 to 5 are excellent in the deodorizing property of the first time, but the deodorizing effect is remarkably reduced after the second time, and when used multiple times. It turns out that it is inferior in deodorizing property.

  Absorption characteristics when the absorbent resin of the present invention was applied to an absorbent article were evaluated. Using the absorbent resin particles obtained in Examples 1 to 7 and Comparative Examples 1 and 2, absorbent articles (paper diapers) were prepared as follows, and the surface dryness value by the SDME method was evaluated. It is shown in Table 2.

<Preparation of absorbent articles (paper diapers)>
120 parts of fluff pulp and 80 parts of an evaluation sample {absorbent resin particles} were mixed with an airflow type mixing apparatus {Pad former manufactured by Autech Co., Ltd.} to obtain a mixture. laminated on m ² and so as to uniformly acrylic plate (thickness 4 mm), and pressed for 30 seconds at a pressure of 5 kg / cm ^2, to obtain absorbent body (1). This absorbent body (1) is cut into a 10 cm × 40 cm rectangle, and water absorbent paper (basis weight 15.5 g / m ² , manufactured by Advantech, filter paper No. 2) having the same size as the absorbent body is arranged above and below each. Further, a paper diaper (1) was prepared by disposing a polyethylene sheet (polyethylene film UB-1 manufactured by Tamapoly Co., Ltd.) on the back surface and a non-woven fabric (basis weight 20 g / m ² , Eltas Guard manufactured by Asahi Kasei Co., Ltd.) on the surface. The weight ratio of the absorbent resin particles to the fibers (weight of the absorbent resin particles / weight of the fibers) was 40/60.

<Surface dryness value by SDME method>
A disposable diaper {artificial urine (0.03% by weight of potassium chloride, 0.08% by weight of magnesium sulfate, 0.88% by weight of sodium sulfate, 0.8% by weight of sodium chloride) in which the detector of the SDME (Surface Dryness Measurement Equipment) tester (manufactured by WK system) is sufficiently moistened. % And deionized water 99.09% by weight) and a paper diaper was soaked for 60 minutes. }, A 0% dryness value was set, and then the detector of the SDME tester was prepared by drying a paper diaper {paper diaper at 80 ° C. for 2 hours by heating. } Was set to 100% dryness, and the SDME tester was calibrated. Next, set a metal ring (inner diameter 70 mm, length 50 mm) in the center of the paper diaper to be measured, inject 80 ml of artificial urine, and absorb the artificial urine {until no gloss can be confirmed by artificial urine}, immediately Remove the metal ring, place three SDME detectors on the center of the paper diaper and its left and right sides (three locations at equal intervals of 10 cm from the end of the 40 cm paper diaper), and start measuring the surface dryness value, 5 minutes after the start of the measurement Were the surface dryness value (1-1) {center}, the surface dryness value (1-2) {left}, and the surface dryness value (1-3) {right}, respectively.
The artificial urine, measurement atmosphere, and standing atmosphere were 25 ± 5 ° C. and 65 ± 10% RH.

As can be seen from Table 2, the absorbent article using the absorbent resin particles of the present invention has the same absorption characteristics as the comparative absorbent resin particles.
That is, even if the absorbent resin particles of the present invention have a deodorizing performance when used multiple times, the absorption is the same as a general absorbent resin having no deodorizing property when applied to absorbent articles. It was shown to have characteristics. Therefore, even if it uses the absorbent article to which the absorbent resin particle of this invention is applied, it turns out that there is no problem in fogging and leakage performance.

  The absorbent resin particles of the present invention can be applied to an absorbent body containing absorbent resin particles and a fibrous material, and absorbent articles {paper diapers, sanitary napkins, and medical blood retaining bodies comprising the absorbent body. It is useful for the agent}. In addition, pet urine absorbent, urine gelling agent for portable toilets, freshness preservation agent for fruits and vegetables, drip absorbent for meat and seafood, cooler, disposable warmer, battery gelling agent, water retention agent for plants and soil, dew condensation It can also be used in various applications such as inhibitors, water-stopping agents, packing agents and artificial snow.

Claims (5)

A cross-linked polymer (A) having a water-soluble vinyl monomer (a1) and / or a hydrolyzable vinyl monomer (a2) and a cross-linking agent (b) as essential constituent units and a deodorant substance (C ) and an absorption water absorbent resin particles comprising the, absorption water within the absorption water resin particles (C) obtained by present 0.01 to 5.0% by weight relative to the weight of (a) Resin particles. Deodorizing substance (C) is a particulate, absorption water absorbing resin particles of claim 1 wherein the weight average particle diameter of 0.01~100μm of (C). Absorption water absorbent resin particles according to claim 1 or 2 shape of the intake water absorbent resin particles are irregularly pulverized. Intake water body comprising the absorption water absorbent resin particles and fibrous material according to any of claims 1-3. Absorption water article with absorption water body according to claim 4.