WO2020105277A1 - Easily dehydratable water-absorbent resin particles and production method thereof - Google Patents

Easily dehydratable water-absorbent resin particles and production method thereof

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Publication number
WO2020105277A1
WO2020105277A1 PCT/JP2019/037462 JP2019037462W WO2020105277A1 WO 2020105277 A1 WO2020105277 A1 WO 2020105277A1 JP 2019037462 W JP2019037462 W JP 2019037462W WO 2020105277 A1 WO2020105277 A1 WO 2020105277A1
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WIPO (PCT)
Prior art keywords
water
absorbent resin
resin particles
vinyl monomer
acid
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PCT/JP2019/037462
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French (fr)
Japanese (ja)
Inventor
森田　英二
敬士 中渕
宮島　徹
鈴木　一充
Original Assignee
三洋化成工業株式会社
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Application filed by 三洋化成工業株式会社 filed Critical 三洋化成工業株式会社
Priority to CN201980076611.5A priority Critical patent/CN113166432B/en
Publication of WO2020105277A1 publication Critical patent/WO2020105277A1/en

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    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J3/00—Processes of treating or compounding macromolecular substances
    • C08J3/12—Powdering or granulating
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J5/00—Manufacture of articles or shaped materials containing macromolecular substances
    • C—CHEMISTRY; METALLURGY
    • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10L—FUELS NOT OTHERWISE PROVIDED FOR; NATURAL GAS; SYNTHETIC NATURAL GAS OBTAINED BY PROCESSES NOT COVERED BY SUBCLASSES C10G, C10K; LIQUEFIED PETROLEUM GAS; ADDING MATERIALS TO FUELS OR FIRES TO REDUCE SMOKE OR UNDESIRABLE DEPOSITS OR TO FACILITATE SOOT REMOVAL; FIRELIGHTERS
    • C10L5/00—Solid fuels
    • C10L5/40—Solid fuels essentially based on materials of non-mineral origin
    • C10L5/48—Solid fuels essentially based on materials of non-mineral origin on industrial residues and waste materials
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J2333/00—Characterised by the use of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical, or of salts, anhydrides, esters, amides, imides, or nitriles thereof; Derivatives of such polymers
    • C08J2333/02—Homopolymers or copolymers of acids; Metal or ammonium salts thereof

Definitions

  • the present invention relates to water-absorbent resin particles that can be easily dehydrated and a method for producing the same.
  • Patent Document 1 a technique relating to a system for separating and collecting water-absorbent resin particles and other members of hygiene articles by using lime (Patent Document 1), after dehydrating and aggregating the water-absorbent resin particles by using an aqueous calcium chloride solution, A technique of adding a salt of a strong acid and a nitrogen-containing basic compound to reduce the cohesive force and facilitating subsequent drying (Patent Document 2), and a used superabsorbent polymer was dehydrated with a polyvalent metal salt aqueous solution.
  • Patent Document 3 a technique for recovering the water absorption capacity of the superabsorbent polymer
  • Patent Document 4 A technique for producing recycled pulp that can be reused for sanitary products by decomposing a super absorbent polymer by ozone treatment has been proposed.
  • the present invention relates to a crosslinked polymer (A) containing a water-soluble vinyl monomer (a1) and / or a vinyl monomer (a2) which becomes a water-soluble vinyl monomer (a1) by hydrolysis and an internal crosslinking agent (b) as essential constituent units.
  • A crosslinked polymer
  • a1 water-soluble vinyl monomer
  • a2 vinyl monomer
  • a2 which becomes a water-soluble vinyl monomer (a1) by hydrolysis
  • an internal crosslinking agent (b) as essential constituent units.
  • Water-absorbent resin particles containing water and having a water separation rate of 70% or more represented by the following formula (1) which is easy to be dehydrated, and hygiene products containing the same.
  • the present invention also relates to the above-mentioned method for producing water-absorbent resin particles, which comprises a water-soluble vinyl monomer (a1) and / or a vinyl monomer (a2) which becomes a water-soluble vinyl monomer (a1) by hydrolysis and an internal cross-linking agent (b).
  • the water-absorbent resin particles of the present invention that can be easily dehydrated exhibit excellent water separation properties when treated with a dehydrating agent.
  • hygiene articles such as paper diapers containing the water-absorbent resin particles of the present invention, while satisfying the required absorption performance as a paper diaper at the time of use, by the addition of a dehydrating agent such as a polyvalent metal salt aqueous solution after use,
  • a dehydrating agent such as a polyvalent metal salt aqueous solution after use
  • the water content can be significantly reduced, and dehydration treatment can be easily performed. Therefore, the combustion efficiency at the time of incineration and the productivity at the time of recycling are improved, and the environmental load can be reduced.
  • FIG. 3 is a perspective view schematically showing a pressurizing shaft and a weight for measuring a gel passage rate.
  • the water-absorbent resin particles of the present invention are crosslinked with the water-soluble vinyl monomer (a1) and / or the vinyl monomer (a2) that becomes a water-soluble vinyl monomer (a1) by hydrolysis and an internal crosslinking agent (b) as essential constituent units.
  • the water-soluble vinyl monomer (a1) in the present invention is not particularly limited, and known monomers such as at least one water-soluble substituent and an ethylenic vinyl group disclosed in paragraphs 0007 to 0023 of Japanese Patent No. 3648553 are used.
  • Vinyl monomers having a saturated group for example, anionic vinyl monomers, nonionic vinyl monomers and cationic vinyl monomers), anionic vinyl monomers and nonionic compounds disclosed in paragraphs 0009 to 0024 of JP-A-2003-165883.
  • Vinyl monomer and cationic vinyl monomer and selected from the group consisting of carboxy group, sulfo group, phosphono group, hydroxyl group, carbamoyl group, amino group and ammonio group disclosed in paragraphs 0041 to 0051 of JP-A-2005-75982.
  • Vinyl monomers having at least one of
  • the vinyl monomer (a2) (hereinafter, also referred to as a hydrolyzable vinyl monomer (a2)) that becomes a water-soluble vinyl monomer (a2) by hydrolysis is not particularly limited and is publicly known (for example, 0024 to 0025 of Japanese Patent No. 3648553).
  • a vinyl monomer having a decomposable substituent (a vinyl monomer having a 1,3-oxo-2-oxapropylene (—CO—O—CO—) group, an acyl group, a cyano group, 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" means a property of being hydrolyzed by being hydrolyzed by the action of water at 50 ° C and, if necessary, a catalyst (acid or base etc.).
  • the hydrolysis (a2) of the hydrolyzable vinyl monomer may be carried out during the polymerization, after the polymerization, or both of them, but the polymerization is preferable from the viewpoint of the molecular weight of the water-absorbent resin particles to be obtained.
  • the water-soluble vinyl monomer (a1) is preferable from the viewpoint of absorption characteristics.
  • the water-soluble vinyl monomer (a1) is preferably an anionic vinyl monomer, more preferably a carboxy (salt) group, a sulfo (salt) group, an amino group, a carbamoyl group, an ammonio group or a mono-, di- or tri-alkyl group. It is a vinyl monomer having an ammonio group.
  • a vinyl monomer having a carboxy (salt) group or a carbamoyl group further preferably (meth) acrylic acid (salt) and (meth) acrylamide, particularly preferably (meth) acrylic acid (salt), Most preferably, it is acrylic acid (salt).
  • a “carboxy (salt) group” means a “carboxy group” or a “carboxylate group”
  • a “sulfo (salt) group” means a “sulfo group” or a “sulfonate group”.
  • (meth) acrylic acid (salt) means acrylic acid, acrylic acid salt, methacrylic acid or methacrylic acid salt
  • (meth) acrylamide means acrylamide or methacrylamide.
  • the salt include alkali metal (lithium, sodium and potassium etc.) salts, alkaline earth metal (magnesium and calcium etc.) salts, ammonium (NH 4 ) salts and the like. Among these salts, alkali metal salts and ammonium salts are preferable, alkali metal salts are more preferable, and sodium salts are particularly preferable, from the viewpoint of absorption characteristics.
  • an acid group-containing monomer such as acrylic acid or methacrylic acid
  • a base from the viewpoint of water absorption performance and residual monomer.
  • alkali metal hydroxides such as sodium hydroxide and potassium hydroxide
  • alkali metal carbonates such as sodium carbonate, sodium hydrogen carbonate and potassium carbonate
  • Neutralization, in the production of the water-absorbent resin particles, before the polymerization, during the polymerization, after the polymerization may be performed any of these, for example, a method of neutralizing the acid group-containing monomer before the polymerization or after the polymerization.
  • a preferable example is a method of neutralizing the acid group-containing polymer in the state of a water-containing gel.
  • the degree of neutralization of the acid group when using the acid group-containing monomer is preferably 50 to 80 mol%.
  • the degree of neutralization is less than 50 mol%, the resulting hydrogel polymer may have high tackiness, which may deteriorate workability during production and use. Further, the water retention amount of the resulting water-absorbent resin particles may decrease.
  • the degree of neutralization exceeds 80%, the pH of the obtained resin becomes high, and there is a concern about the safety of the skin of human body.
  • each may be a constitutional unit independently, or if necessary, two or more types may be constitutional units.
  • the molar ratio (a1 / a2) of these is preferably 75/25 to 99/1, and more preferably 85/15 to 95/5, particularly preferably 90/10 to 93/7, most preferably 91/9 to 92/8. Within this range, the absorption performance is further improved.
  • the other copolymerizable vinyl monomer (a3) is not particularly limited and is well known (for example, the hydrophobic vinyl monomer disclosed in paragraphs 0028 to 0029 of Japanese Patent No. 3648553, JP-A-2003-165883, JP Hydrophobic vinyl monomers such as vinyl monomers disclosed in paragraph 0058 of Japanese Unexamined Patent Publication No. 2005-75982 can be used, and the following vinyl monomers (i) to (iii) can be used.
  • (I) Aromatic ethylenic monomer having 8 to 30 carbon atoms Styrene such as styrene, ⁇ -methylstyrene, vinyltoluene and hydroxystyrene, and halogen-substituted styrene such as vinylnaphthalene and dichlorostyrene.
  • Styrene such as styrene, ⁇ -methylstyrene, vinyltoluene and hydroxystyrene
  • halogen-substituted styrene such as vinylnaphthalene and dichlorostyrene.
  • the content (mol%) of the other vinyl monomer (a3) unit is the same as that of the water-soluble vinyl monomer (a1) unit and the hydrolyzable vinyl monomer (a2) unit. It is preferably 0.01 to 5, more preferably 0.05 to 3, still more preferably 0.08 to 2, and particularly preferably 0.1 to 1.5, based on the number of moles. Despite the above, it is most preferable that the content of the other vinyl monomer (a3) unit is 0 mol% from the viewpoint of absorption characteristics.
  • the internal cross-linking agent (b) (hereinafter, also simply referred to as the cross-linking agent (b)) is not particularly limited and is publicly known (for example, the ethylenically unsaturated group disclosed in paragraphs 0031 to 0034 of Japanese Patent No. 3648553 is 2). At least one cross-linking agent, a cross-linking agent having at least one functional group capable of reacting with a water-soluble substituent and having at least one ethylenically unsaturated group, and a functional group capable of reacting with a water-soluble substituent.
  • a cross-linking agent of cross-linkable vinyl monomer can be used.
  • a crosslinking agent having two or more ethylenically unsaturated groups is preferable from the viewpoint of absorption performance and the like, and more preferable are poly (poly (aryl) (triallyl cyanurate, triallyl isocyanurate, and polyol having 2 to 10 carbon atoms).
  • (Meth) allyl ether particularly preferred are triallyl cyanurate, triallyl isocyanurate, tetraallyloxyethane and pentaerythritol triallyl ether, most preferred is pentaerythritol triallyl ether.
  • the crosslinking agent (b) one type may be used alone, or two or more types may be used in combination.
  • the content (mol%) of the crosslinking agent (b) unit is from (a1) to (a1) when the other vinyl monomer (a3) of the water-soluble vinyl monomer (a1) unit and the hydrolyzable vinyl monomer (a2) unit is used. Based on the total number of moles of (a3), it is preferably 0.001 to 5, more preferably 0.005 to 3, and particularly preferably 0.01 to 1. Within this range, the absorption performance will be further improved.
  • the method for producing water-absorbent resin particles of the present invention is a monomer composition containing the above-mentioned water-soluble vinyl monomer (a1) and / or hydrolyzable vinyl monomer (a2) and an internal crosslinking agent (b) as essential constituent units.
  • Polymerization step to obtain a hydrogel containing the crosslinked polymer (A) a step of subdividing the hydrogel of the crosslinked polymer (A), and further kneading the subdivided hydrogel at a gel temperature of 40 ° C to 120 ° C.
  • the method includes a step of shredding, and a step of drying and then crushing the kneaded shredded hydrogel to obtain water-absorbent resin particles.
  • Examples of the method for producing the crosslinked polymer (A) include known solution polymerization (adiabatic polymerization, thin film polymerization, spray polymerization, etc .; JP-A-55-133413, etc.), known suspension polymerization method, reverse phase suspension method, etc.
  • a hydrogel containing a crosslinked polymer (A) (consisting of a crosslinked polymer and water) by turbid polymerization Japanese Patent Publication No. 54-30710, Japanese Patent Application Laid-Open No. 56-26909, Japanese Patent Application Laid-Open No. 1-5808, etc.). .
  • the crosslinked polymer (A) may be a single type or a mixture of two or more types.
  • the solution polymerization method is preferable, and since it is advantageous in terms of production cost that it is not necessary to use an organic solvent or the like, particularly preferable is the aqueous solution polymerization method, which has a large water retention amount and is water-soluble.
  • the aqueous solution adiabatic polymerization method is most preferable because a water-absorbent resin having a small amount of components can be obtained and temperature control during polymerization is unnecessary.
  • the concentration of the monomer composition in the aqueous solution is preferably 10 to 60% by weight, more preferably 15 to 50% by weight, and further preferably 20 to 40% by weight.
  • the solvent a mixed solvent containing water and an organic solvent can be used, and as the organic solvent, methanol, ethanol, acetone, methyl ethyl ketone, N, N-dimethylformamide, dimethyl sulfoxide, and a mixture of two or more kinds of them can be used. Can be mentioned.
  • the amount of organic solvent used (% by weight) is preferably 40 or less, and more preferably 30 or less, based on the weight of water.
  • radical polymerization initiators When an initiator is used for the polymerization, conventionally known radical polymerization initiators can be used, and examples thereof include azo compounds [azobisisobutyronitrile, azobiscyanovaleric acid and 2,2′-azobis (2-amidinopropane).
  • Inorganic peroxides hydrogen peroxide, ammonium persulfate, potassium persulfate, sodium persulfate, etc.
  • Organic peroxides benzoyl peroxide, di-t-butyl peroxide, cumene hydroperoxide, amber Acid peroxide and di (2-ethoxyethyl) peroxydicarbonate, etc.
  • redox catalyst alkali metal sulfite or bisulfite, ammonium sulfite, ammonium bisulfite, ascorbic acid and other reducing agents and alkali metal persulfate
  • an oxidizing agent such as a salt, ammonium persulfate, hydrogen peroxide and an organic peroxide.
  • the amount (% by weight) of the radical polymerization initiator is the same as that of the water-soluble vinyl monomer (a1) and the hydrolyzable vinyl monomer (a2) or (a1) to (a3) when other vinyl monomer (a3) is used. Based on the total weight, 0.0005 to 5 is preferable, and 0.001 to 2 is more preferable.
  • the polymerization method is a suspension polymerization method or a reverse phase suspension polymerization method
  • the polymerization may be carried out in the presence of a conventionally known dispersant or surfactant, if necessary.
  • the reverse phase suspension polymerization method the polymerization can be carried out using a conventionally known hydrocarbon solvent such as xylene, normal hexane, and normal heptane.
  • the polymerization initiation temperature can be appropriately adjusted depending on the type of initiator used, but is preferably 0 to 100 ° C, more preferably 5 to 80 ° C.
  • the hydrogel polymer obtained by the polymerization can be kneaded, shredded, dried, and then pulverized to obtain the crosslinked polymer (A).
  • Kneading and shredding in the present invention is a step of finely cutting the hydrous gel by repeating cutting of the hydrous gel by shearing force (shear) and coalescence of the cut hydrous gel particles.
  • a hydrogel obtained by aggregating gel particles is obtained, and irregularities can be formed on the surface of the water absorbent resin particles.
  • the size (longest diameter) of the gel after kneading and shredding is preferably 50 ⁇ m to 10 cm, more preferably 100 ⁇ m to 2 cm, and particularly preferably 1 mm to 1 cm. Within this range, the drying property in the drying step becomes even better.
  • the size (longest diameter) of the gel particles after kneading and pulverization is preferably 50 ⁇ m to 10 cm, more preferably 100 ⁇ m to 2 cm, and particularly preferably 1 mm to 1 cm. Within this range, the drying property in the drying process is further improved, and the mixing property with the hydrophobic substance (c) as an additive is also improved, resulting in a water separation rate or 1.0% by weight calcium chloride. The gel flow rate of the aqueous solution is improved.
  • the kneading shredding can be performed by a known method, and kneading shredding using a kneading shredding device (eg, kneader, universal mixer, uniaxial or biaxial kneading extruder, mincing machine, meat chopper, etc.) it can. From the viewpoint of dehydration efficiency and performance balance with other physical properties, it is 40 to 120 ° C., preferably 50 to 110 ° C.
  • the number of kneading and shredding is not particularly limited as long as the size of the gel particles is within the above range, and may be once or plural times. When kneading and shredding is performed a plurality of times, it may be performed a plurality of times with one crushing device or may be continuously performed with a plurality of crushing devices.
  • the hydrogel polymer obtained by polymerization is subdivided before kneading and chopping.
  • subdivision is a step of cutting the hydrogel into fine pieces while maintaining the internal structure of the hydrogel, which is different from the kneading chopping described above from the viewpoint of the internal structure.
  • the method of subdividing is not particularly limited, and may be subdivided by, for example, scissors, and a frozen water-containing gel is pulverized (for example, a hammer pulverizer, an impact pulverizer, a roll pulverizer and a shet airflow pulverizer). ).
  • a frozen water-containing gel is pulverized (for example, a hammer pulverizer, an impact pulverizer, a roll pulverizer and a shet airflow pulverizer).
  • the size (longest diameter) of the gel after subdivision is preferably 50 ⁇ m to 10 cm, more preferably 100 ⁇ m to 2 cm, and particularly preferably 500 ⁇ m to 1 cm. Within this range, the subsequent kneading and shredding step can be carried out smoothly, and the absorbent performance of the water-absorbent resin particles may be improved.
  • the hydrogel of the acid group-containing polymer obtained after the polymerization can be neutralized by mixing a base before or during the kneading shredding step.
  • the preferable range of the degree of neutralization of the acid group when the acid group-containing polymer is neutralized is the same as described above.
  • the water-absorbent resin particles are obtained by drying and then pulverizing the hydrogel particles containing the crosslinked polymer (A) obtained in the kneading and chopping step.
  • a method for drying (including distilling) the solvent (including water) in the hydrogel particles a method of drying with hot air at a temperature of 80 to 300 ° C., a thin film formed by a drum dryer heated to 100 to 300 ° C.
  • a drying method, a reduced pressure drying method, a freeze drying method, an infrared ray drying method, decantation, filtration and the like can be applied.
  • the water content (% by weight) after drying is preferably 0 to 20, more preferably 1 to 10, and particularly preferably, based on the weight of the crosslinked polymer (A). It is 2-9, most preferably 3-8. Within this range, the pulverizability will be good in the subsequent pulverization step, and the absorption performance will be even better.
  • the content (% by weight) of the organic solvent after drying is 0 to 10 based on the weight of the crosslinked polymer (A). Is more preferable, 0 to 5 is more preferable, 0 to 3 is particularly preferable, and 0 to 1 is the most preferable. Within this range, the absorbent performance of the water absorbent resin particles will be further improved.
  • the content and water content of the organic solvent are infrared moisture meter [JE400 manufactured by KETT Co., Ltd .: 120 ⁇ 5 ° C., 30 minutes, atmospheric humidity before heating 50 ⁇ 10% RH, lamp specification 100V, 40 W] and the weight loss of the measurement sample when heated.
  • the method of pulverizing the hydrogel particles after drying is not particularly limited, and a known pulverizing device (for example, a hammer pulverizer, an impact pulverizer, a roll pulverizer, a shet airflow pulverizer, etc.) can be used. ..
  • a known pulverizing device for example, a hammer pulverizer, an impact pulverizer, a roll pulverizer, a shet airflow pulverizer, etc.
  • the resulting water-absorbent resin particles can be classified by sieving or the like to adjust the particle size, if necessary.
  • the weight average particle diameter ( ⁇ m) of the water-absorbent resin particles that have been classified by sieving or the like after crushing is preferably 150 to 500, more preferably 250 to 500, and most preferably 350 to 450. Within this range, the absorption performance, the water separation rate, and the gel permeation rate of the 1.0 wt% calcium chloride aqueous solution are further improved.
  • the weight average particle size is determined by using a low tap test sieve shaker and a standard sieve (JIS Z8801-1: 2006), Perry's Chemical Engineers Handbook 6th Edition (MacGlow Hill Book Company, 1984). , Page 21). That is, the JIS standard sieve is combined from the top in the order of 1000 ⁇ m, 850 ⁇ m, 710 ⁇ m, 500 ⁇ m, 425 ⁇ m, 355 ⁇ m, 250 ⁇ m, 150 ⁇ m, 125 ⁇ m, 75 ⁇ m and 45 ⁇ m, and a saucer. About 50 g of the measurement particles are put into the uppermost sieve and shaken for 5 minutes with a low tap test sieve shaker.
  • the weight of the measured particles on each sieve and the pan is weighed, and the total is 100% by weight to obtain the weight fraction of the particles on each sieve.
  • This value is used as a logarithmic probability paper [the horizontal axis is the sieve opening (particle size ), And the vertical axis is the weight fraction], and a line connecting the points is drawn to obtain the particle diameter corresponding to the weight fraction of 50% by weight, which is taken as the weight average particle diameter.
  • the content rate of the fine particles of 106 ⁇ m or less (preferably 150 ⁇ m or less) in the total weight of the water-absorbent resin particles (weight) %) Is preferably 3 or less, more preferably 1 or less.
  • the content of the fine particles can be determined using the graph created when determining the weight average particle size.
  • the shape of the water-absorbent resin particles is not particularly limited, and examples thereof include irregularly crushed particles, flaky particles, pearl particles, and rice particles. Among them, the amorphous crushed shape is preferable from the viewpoint that it has good entanglement with the fibrous material for use in disposable diapers and the like, and there is no fear of falling off from the fibrous material.
  • the water absorbent resin particles of the present invention can contain a hydrophobic substance (c).
  • a hydrophobic substance (c) include a hydrophobic substance (c1) containing a hydrocarbon group, a hydrophobic substance (c2) containing a hydrocarbon group having a fluorine atom, and a hydrophobic substance (c3) having a polysiloxane structure. Be done.
  • hydrophobic substance (c1) containing a hydrocarbon group polyolefin resin, polyolefin resin derivative, polystyrene resin, polystyrene resin derivative, wax, long chain fatty acid ester, long chain fatty acid and its salt, long chain aliphatic alcohol, long chain Included are chain aliphatic amides and mixtures of two or more of these.
  • the polyolefin resin a weight of an olefin having 2 to 4 carbon atoms (ethylene, propylene, isobutylene, isoprene, etc.) as an essential constituent monomer (the content of the olefin is at least 50% by weight based on the weight of the polyolefin resin).
  • examples thereof include polymers having an average molecular weight of 1,000 to 1,000,000 (eg, polyethylene, polypropylene, polyisobutylene, poly (ethylene-isobutylene), isoprene, etc.).
  • polystyrene resin derivative a polymer having a weight average molecular weight of 1,000 to 1,000,000 obtained by introducing a carboxy group (—COOH), 1,3-oxo-2-oxapropylene (—COOCO—) or the like into a polyolefin resin (for example, polyethylene heat Degradation products, polypropylene thermal degradation products, maleic acid modified polyethylene, chlorinated polyethylene, maleic acid modified polypropylene, ethylene-acrylic acid copolymers, ethylene-maleic anhydride copolymers, isobutylene-maleic anhydride copolymers, maleated Polybutadiene, ethylene-vinyl acetate copolymer, and ethylene-vinyl acetate copolymer maleated product ⁇ .
  • a polyolefin resin for example, polyethylene heat Degradation products, polypropylene thermal degradation products, maleic acid modified polyethylene, chlorinated polyethylene, maleic acid modified polypropylene, ethylene-acrylic acid cop
  • polystyrene resin a polymer having a weight average molecular weight of 1,000 to 1,000,000 can be used.
  • polystyrene resin derivative a polymer having a weight average molecular weight of 1,000 to 1,000,000 (for example, styrene-containing styrene as an essential constituent monomer (the content of styrene is at least 50% by weight based on the weight of the polystyrene derivative))
  • styrene-containing styrene as an essential constituent monomer (the content of styrene is at least 50% by weight based on the weight of the polystyrene derivative)
  • maleic anhydride copolymers, styrene-butadiene copolymers and styrene-isobutylene copolymers a polymer having a weight average molecular weight of 1,000 to 1,000,000
  • maleic anhydride copolymers styrene-butadiene copolymers
  • styrene-isobutylene copolymers styrene-isobutylene cop
  • waxes having a melting point of 50 to 200 ° C. for example, paraffin wax, beeswax, carnauba wax, beef tallow, etc.
  • the long-chain fatty acid ester is an ester of a fatty acid having 8 to 30 carbon atoms and an alcohol having 1 to 12 carbon atoms (for example, methyl laurate, ethyl laurate, methyl stearate, ethyl stearate, methyl oleate, oleic acid).
  • long-chain fatty acids and salts thereof include fatty acids having 8 to 30 carbon atoms (for example, lauric acid, palmitic acid, stearic acid, oleic acid, dimer acid, behenic acid, etc.), and salts thereof include zinc, calcium, Examples thereof include salts with magnesium or aluminum (hereinafter abbreviated as Zn, Ca, Mg, and Al) ⁇ for example, Ca palmitate, Al palmitate, Ca stearate, Mg stearate, Al stearate, etc.).
  • Zn, Ca, Mg, and Al magnesium or aluminum
  • long-chain aliphatic alcohols include aliphatic alcohols having 8 to 30 carbon atoms (eg, lauryl alcohol, palmityl alcohol, stearyl alcohol, oleyl alcohol, etc.). From the viewpoint of leakage resistance of the absorbent article, palmityl alcohol, stearyl alcohol and oleyl alcohol are preferable, and stearyl alcohol is more preferable.
  • 1 and 1 are obtained by reacting a primary amine with a carboxylic acid at a ratio of 1: 1. : It can be divided into two reacted products.
  • the reaction product at 1: 1 include acetic acid N-octylamide, acetic acid N-hexacosylamide, heptacosanoic acid N-octylamide, and heptacosanoic acid N-hexacosylamide.
  • Examples of the reaction of 1: 2 include diacetic acid N-octylamide, diacetic acid N-hexacosylamide, diheptacosanoic acid N-octylamide and diheptacosanoic acid N-hexacosylamide.
  • the primary amine and the carboxylic acid are reacted at a ratio of 1: 2, the carboxylic acids used may be the same or different.
  • the amidated product of ammonia or a primary amine having 1 to 7 carbon atoms and a long-chain fatty acid having 8 to 30 carbon atoms is 1: 2 with a reaction product of ammonia or primary amine and carboxylic acid at 1: 1. It can be divided into reacted products.
  • the reaction products of 1: 1 are nonanoic acid amide, nonanoic acid methylamide, nonanoic acid N-heptylamide, heptacosanoic acid amide, heptacosanoic acid N-methylamide, heptacosanoic acid N-heptylamide and heptacosanoic acid N-hexacosylamide.
  • the reaction of 1: 2 includes dinonanoic acid amide, dinonanoic acid N-methylamide, dinonanoic acid N-heptylamide, dioctadecanoic acid amide, dioctadecanoic acid N-ethylamide, dioctadecanoic acid N-heptylamide, diheptacosanoic acid amide. , Diheptacosanoic acid N-methylamide, diheptacosanoic acid N-heptylamide, diheptacosanoic acid N-hexacosylamide and the like.
  • the carboxylic acid used may be the same or different as the reaction product of ammonia or primary amine and carboxylic acid in a ratio of 1: 2.
  • amidation product of a long-chain aliphatic secondary amine having at least one aliphatic chain having 8 to 30 carbon atoms and a carboxylic acid having 1 to 30 carbon atoms acetic acid N-methyloctylamide, acetic acid N-methylhexacosyl Lamide, acetic acid N-octylhexacosylamide, acetic acid N-dihexacosylamide, heptacosanoic acid N-methyloctylamide, heptacosanoic acid N-methylhexacosylamide, heptacosanoic acid N-octylhexacosylamide and heptacosane Examples thereof include acid N-dihexacosylamide.
  • nonanoic acid N-dimethylamide As the amidation product of a secondary amine having two aliphatic hydrocarbon groups having 1 to 7 carbon atoms and a long chain fatty acid having 8 to 30 carbon atoms, nonanoic acid N-dimethylamide, nonanoic acid N-methylheptylamide, Examples thereof include nonanoic acid N-diheptylamide, heptacosanoic acid N-dimethylamide, heptacosanoic acid N-methylheptylamide and heptacosanoic acid N-diheptylamide.
  • the hydrophobic substance (c1) is preferably a long-chain fatty acid ester, a long-chain fatty acid and its salt, a long-chain aliphatic alcohol and a long-chain aliphatic amide, from the viewpoint of dehydration efficiency and the moisture resistance of the absorbent article, and further, Preferred are sorbit stearate, sucrose stearate, stearic acid, Mg stearate, Ca stearate, Zn stearate and Al stearate, and particularly preferred are sucrose stearate and Mg stearate.
  • hydrophobic substance (c2) containing a hydrocarbon group having a fluorine atom examples include perfluoroalkane, perfluoroalkene, perfluoroaryl, perfluoroalkyl ether, perfluoroalkylcarboxylic acid, perfluoroalkyl alcohol and these 2 Mixtures of more than one species are included.
  • hydrophobic substance (c3) having a polysiloxane structure polydimethylsiloxane, polyether-modified polysiloxane ⁇ polyoxyethylene-modified polysiloxane and poly (oxyethylene / oxypropylene) -modified polysiloxane, etc. ⁇ , carboxy-modified polysiloxane, Epoxy-modified polysiloxane, amino-modified polysiloxane, alkoxy-modified polysiloxane and the like, and mixtures thereof are included.
  • Examples of the carboxy-modified polysiloxane include X-22-3701E, X-22-3710 (all manufactured by Shin-Etsu Chemical Co., Ltd.), DOWSIL (model number BY16-880Fluid), and DOWNSIL (model number BY16-880) (Dow-Toray shares). Company made) etc.
  • the position of the carboxyl group with respect to the polysiloxane main chain is a side chain and / or a terminal.
  • Examples of the epoxy-modified polysiloxane include X-22-343 (manufactured by Shin-Etsu Chemical Co., Ltd.), KF-101, KF-1001, X-22-2000, X-22-2046, KF-102, X-22-.
  • the position of the epoxy group with respect to the polysiloxane main chain is a side chain and / or a terminal.
  • Examples of the amino-modified polysiloxane include a monoamine-modified type having a primary amine as a modifying group and a diamine-modified type having a secondary amine.
  • Examples of the monoamino-modified type include KF-868, KF-865, KF-864, PAM-E, KF-8010, X-22-161A, X-22-161B, KF-8012, KF-8008, X- 22-1660B-3, X-22-9409 (all manufactured by Shin-Etsu Chemical Co., Ltd.), DOWSIL (model number BY16-205), DOWSIL (model number BY16-213), DOWNSIL (model number BY16-849Fluid), DOWNSIL (model BY16-).
  • DOWSIL model number BY16-871
  • DOWSIL model number BY16-872
  • DOWSIL model number BY16-879B
  • DOWNSIL model number BY16-892
  • DOWNSIL model number FZ-3705
  • DOWNSIL model number FZ-3710Fluid
  • DOWSIL model number FZ-3760
  • DOWSIL model number FZ-3785
  • DOWSIL model number SF8417Fluid
  • Examples of the diamino-modified type include KF-859, KF-393, KF-860, KF-860, KF-8004, KF-8002, KF-8005, KF-867, KF-8021, KF-869, KF-. 861 (both manufactured by Shin-Etsu Chemical Co., Ltd.) and the like.
  • the position of the diamino group with respect to the polysiloxane main chain is a side chain and / or a terminal.
  • alkoxy-modified polysiloxane examples include X-22-4952, X-22-4272, KF-6123, KF-351A, KF-352A, KF-353, KF-354L, KF-355A, KF-615A and KF.
  • the hydrophobic substance (c3) is preferably a carboxy-modified polysiloxane, an epoxy-modified polysiloxane, an amino-modified polysiloxane, or an alkoxy-modified polysiloxane, and more preferably carboxy-modified, from the viewpoints of the dehydration efficiency and the moisture resistance of the absorbent article. It is a polysiloxane.
  • the HLB value of the hydrophobic substance (c) is preferably 1-10, more preferably 1-8, and particularly preferably 1-7. Within this range, the absorbent article has further improved resistance to leakage.
  • the HLB value means a hydrophilic-hydrophobic balance (HLB) value, and is determined by the Oda method (Surfactant Primer, page 212, Takehiko Fujimoto, Sanyo Chemical Industry Co., Ltd., 2007).
  • the hydrophobic substance (c1) containing a hydrocarbon group or the hydrophobic substance (c3) having a polysiloxane structure is preferable from the viewpoints of dehydration efficiency and leakage resistance of the absorbent article. .. More preferably, it is the hydrophobic substance (c3).
  • the content (% by weight) of the hydrophobic substance (c) is 0.001 to 2.0 based on the weight of the crosslinked polymer (A) from the viewpoint of water absorption characteristics (particularly, water absorption rate and liquid passing rate). %, Preferably 0.01 to 1.0% by weight, particularly preferably 0.02 to 0.3% by weight.
  • the hydrophobic substance (c) may be present at any position of the water absorbent resin particles, but it should be present inside the water absorbent resin particles from the viewpoint of water absorption characteristics (particularly, water absorption rate) and water separation rate. Is preferred.
  • the hydrophobic substance (c) need only be such that the hydrogel containing the crosslinked polymer (A) contains (c) during the above-mentioned kneading and shredding step. ) Is preferably contained.
  • a method of adding (c) a method of adding to the polymerization liquid after the start of the polymerization step and before the completion of the polymerization step, a method of adding to the hydrogel before the kneading shredding step after the completion of the polymerization step, and a kneading shredding Examples include a method of adding to the hydrogel particles during the step, from the viewpoint of improving the water separation rate, a method of adding to the hydrogel before the kneading shredding step after the completion of the polymerization step, or the hydrogel particles during the kneading shredding step. To the hydrogel particles during the kneading and shredding step.
  • the hydrophobic substance (c) can be
  • the production method of the present invention may include a step of drying and pulverizing the above-mentioned hydrogel particles and then surface-crosslinking them.
  • the gel strength can be further improved, and the desired water retention amount and absorption amount under load can be satisfied in actual use.
  • the step of surface-crosslinking the hydrogel particles is also simply referred to as a crosslinking step.
  • a method for surface-crosslinking the water-absorbent resin particles a conventionally known method, for example, a method in which the water-absorbent resin is made into particles, a surface-crosslinking agent (e), water and a mixed solution of a solvent are mixed and the mixture is heated and reacted.
  • the mixing method include spraying the mixed solution onto the water-absorbent resin particles, or a method of dipping the water-absorbent resin particles into the mixed solution, and preferably spraying the mixed solution onto the water-absorbent resin particles. It is a method of mixing.
  • Examples of the surface cross-linking agent (e) include polyglycidyl compounds such as ethylene glycol diglycidyl ether, glycerol diglycidyl ether and polyglycerol polyglycidyl ether, polyhydric alcohols such as glycerin and ethylene glycol, ethylene carbonate, polyamines and polyhydric alcohols. A metal compound etc. are mentioned. Of these, polyglycidyl compounds are preferable because they can be crosslinked at a relatively low temperature. These surface cross-linking agents may be used alone or in combination of two or more.
  • the amount of the surface-crosslinking agent (e) used is preferably 0.001 to 5% by weight, more preferably 0.005 to 2% by weight, based on the weight of the water-absorbent resin particles before crosslinking.
  • the amount of the surface cross-linking agent (e) used is less than 0.001% by weight, the degree of surface cross-linking may be insufficient and the effect of improving the absorption amount under load may be insufficient.
  • the amount of the surface cross-linking agent (e) used exceeds 5% by weight, the degree of cross-linking on the surface becomes excessive and the water retention amount may decrease.
  • the amount of water used for surface crosslinking is preferably 0.5 to 10% by weight, more preferably 1 to 7% by weight, based on the weight of the water-absorbent resin particles before crosslinking.
  • the amount of water used is less than 0.5% by weight, the degree of penetration of the surface cross-linking agent (e) into the water-absorbent resin particles becomes insufficient, and the effect of improving the amount absorbed under load may be poor.
  • the amount of water used exceeds 10% by weight, the penetration of the surface cross-linking agent (e) into the interior becomes excessive, and although the absorption amount under load is improved, the water retention amount may decrease.
  • the solvent used in combination with water at the time of surface cross-linking conventionally known ones can be used, the penetration degree of the surface cross-linking agent (e) into the water-absorbent resin particles, the reactivity of the surface cross-linking agent (e).
  • a hydrophilic organic solvent such as methanol, diethylene glycol or propylene glycol, which is soluble in water, is preferable.
  • the solvent may be used alone or in combination of two or more kinds.
  • the amount of the solvent used can be appropriately adjusted depending on the type of the solvent, but it is preferably 1 to 10% by weight based on the weight of the water-absorbent resin particles before surface crosslinking.
  • the ratio of the solvent to water can be adjusted arbitrarily, but it is preferably 20 to 80% by weight, more preferably 30 to 70% by weight.
  • a mixed solution of the surface cross-linking agent (e), water and a solvent is mixed with the water-absorbent resin particles by a conventionally known method, and a heating reaction is carried out.
  • the reaction temperature is preferably 100 to 230 ° C, more preferably 120 to 180 ° C.
  • the reaction time can be appropriately adjusted depending on the reaction temperature, but is preferably 3 to 60 minutes, more preferably 10 to 45 minutes.
  • the water-absorbent resin particles obtained by surface-crosslinking can be further surface-crosslinked by using the same or different surface-crosslinking agent as the surface-crosslinking agent initially used.
  • the particle size adjusting step after surface-crosslinking the hydrogel particles is also referred to as a post-step after the cross-linking step, or simply as a post-step.
  • the hydrophobic substance (c) can be added to water and / or an organic solvent in a dissolved and / or dispersed form in the crosslinking step and / or the post-step after the crosslinking step.
  • the particles can be uniformly added to the surface of the particles, so that the dehydration efficiency can be improved.
  • the water-absorbent resin particles of the present invention may further contain a polyvalent metal salt (f), and therefore the production method of the present invention may further include a step of mixing with the polyvalent metal salt (f). good.
  • the polyvalent metal salt (f) include salts of at least one metal selected from the group consisting of magnesium, calcium, zirconium, aluminum and titanium and the above-mentioned inorganic acid or organic acid.
  • an inorganic acid salt of aluminum and an inorganic acid salt of titanium are preferable from the viewpoint of easy availability and solubility, and more preferable are aluminum sulfate, aluminum chloride, potassium aluminum sulfate and sulfuric acid.
  • Aluminum aluminum particularly preferred are aluminum sulfate and sodium aluminum sulfate, and most preferred is sodium aluminum sulfate. These may be used alone or in combination of two or more.
  • the amount (% by weight) of the polyvalent metal salt (f) used is preferably 0.01 to 5, more preferably 0. 5, based on the weight of the crosslinked polymer (A) from the viewpoint of absorption performance and blocking resistance.
  • 05 to 4 particularly preferably 0.1 to 3.
  • the timing of mixing with the polyvalent metal salt (f) is not particularly limited, but it is preferable to mix it after the water-containing gel is dried to obtain water-absorbent resin particles, from the viewpoint of absorption performance and blocking resistance. ..
  • the surface of the water-absorbent resin particles of the present invention can be further coated with an inorganic powder.
  • the inorganic powder include hydrophilic inorganic particles and hydrophobic inorganic particles.
  • the hydrophilic inorganic particles include particles of glass, silica gel, silica, clay and the like.
  • the hydrophobic inorganic particles include particles of carbon fiber, kaolin, talc, mica, bentonite, sericite, asbestos and shirasu. Of these, hydrophilic inorganic particles are preferable, and silica is the most preferable.
  • the shape of the hydrophilic inorganic particles and the hydrophobic inorganic particles may be any of amorphous (crushed), spherical, film-shaped, rod-shaped and fibrous, etc., but the amorphous (crushed) or spherical is preferable, The spherical shape is more preferable.
  • the content (% by weight) of the inorganic powder is preferably 0.01 to 3.0, more preferably 0.05 to 1.0, and most preferably 0.1 to 3.0 based on the weight of the water absorbent resin particles. 0.8, particularly preferably 0.2 to 0.7, most preferably 0.3 to 0.6. Within this range, the gel permeation rate of the absorbent article will be further improved.
  • the water-absorbent resin particles of the present invention may contain other additives (for example, known antiseptics, antifungal agents, antibacterial agents, antioxidants, ultraviolet rays, etc. (Japanese Patent Laid-Open Nos. 2003-225565 and 2006-131767). Absorbents, colorants, fragrances, deodorants, organic fibrous substances, etc. ⁇ can also be included.
  • the content (% by weight) of the additive is preferably 0.001 to 10, more preferably 0.01 to 5, and particularly preferably, based on the weight of the water absorbent resin particles. It is 0.05 to 1, most preferably 0.1 to 0.5.
  • the apparent density (g / ml) of the water absorbent resin particles of the present invention is preferably 0.40 to 0.62, more preferably 0.45 to 0.60, and particularly preferably 0.48 to 0.58. .. Within this range, the water separation rate and the gel flow rate are further improved.
  • the apparent density of the water-absorbent resin particles is measured at 25 ° C according to JIS K7365: 1999.
  • the water retention capacity (g / g) of the water-absorbent resin particles of the present invention with respect to physiological saline is preferably 30 to 50, more preferably 33 to 49, further preferably 36 to 48, and particularly 39 to 47. preferable. When it is less than 30, leakage tends to occur during repeated use, which is not preferable. Further, when it exceeds 50, blocking tends to occur, which is not preferable.
  • the water retention amount can be appropriately adjusted by the types and amounts of the crosslinking agent (b) and the surface crosslinking agent (e). Therefore, for example, when it is necessary to increase the water retention amount, it can be easily realized by reducing the amounts of the crosslinking agent (b) and the surface crosslinking agent (e) used.
  • the gel permeation rate (ml / min) of the physiological saline of the water-absorbent resin particles of the present invention is preferably 5 to 250, more preferably 10 to 230, and particularly preferably 30 to 210. If the gel flow rate (ml / min) of physiological saline is less than 5, the diffusivity of the liquid may decrease, and as a result, leakage or rash may occur. If it exceeds 250, the diffusivity of the liquid may be too large. However, there is a concern that the water-absorbent resin particles may leak from the absorbent before being absorbed by the water-absorbent resin particles.
  • the water separation rate in the present invention is a value represented by the following formula (1), and a water retention amount with respect to physiological saline and a water retention amount after the swelling gel after the water retention amount measurement is treated with a 1.0 wt% calcium chloride aqueous solution. It is calculated from the ratio of That is, the weight ratio of the separated water after the treatment to the weight of the swollen gel before the treatment with the dehydrating agent is shown. Therefore, it means that the higher the water separation rate, the more excellent the dehydration efficiency by the predetermined dehydrating agent treatment.
  • Water separation rate [%] ⁇ 1- (water retention amount after treatment with 1.0 wt% calcium chloride aqueous solution [g / g]) / (water retention amount against physiological saline [g / g]) ⁇ ⁇ 100 (1) The specific measuring method will be described later.
  • the water separation ratio (%) of the water absorbent resin particles of the present invention is 70 or more, more preferably 73 or more, and particularly preferably 75 or more.
  • As a means for improving the water separation rate it is conceivable to widen the specific surface area of the particles or adjust the balance between hydrophilicity and hydrophobicity inside or on the surface of the particles.
  • a polymerization step, a kneading shredding step, a crosslinking step, and / or a combined use of a hydrophobic substance in a post-step after the crosslinking step, or the gel temperature in the step of kneading a hydrous gel Adjustment raising the heating temperature during drying when dehydrating from the hydrogel, raising the heating temperature in the crosslinking step, lowering the weight average particle diameter and the like can be mentioned.
  • the gel temperature in the step of kneading the hydrous gel is preferably 40 to 120 ° C., more preferably 50 to 110 ° C. from the viewpoint of dehydration efficiency and performance balance with other physical properties.
  • the heating temperature for drying the water-containing gel during dehydration is preferably 100 to 300 ° C., more preferably 110 to 280 ° C., from the viewpoint of performance balance with other physical properties and productivity. Heating above 300 ° C. is not preferable because the water-absorbent resin particles undergo thermal deterioration.
  • the heating temperature in the cross-linking step is preferably 100 to 230 ° C, more preferably 120 to 180 ° C. Within this range, it is considered that the hydrophobic substance melts, or the viscosity decreases to coat the surface of the absorbent resin particles, thereby preventing the gels from coalescing and increasing the number of reaction points with the dehydrating agent. Be done.
  • the weight average particle diameter is preferably 150 ⁇ m to 500 ⁇ m, and more preferably 200 ⁇ m to 400 ⁇ m, from the viewpoint of the balance of performance between dehydration and other physical properties.
  • the re-swelling ratio (%) of the water-absorbent resin particles of the present invention with ion-exchanged water is a value represented by the following formula (2), and the swollen gel after water retention measurement is dehydrated with a 1.0 wt% calcium chloride aqueous solution. After the treatment, it is calculated from the ratio of the water retention amount re-swelled with ion-exchanged water and the water retention amount with respect to physiological saline. Therefore, the lower the re-swelling ratio with ion-exchanged water, the more the dehydration effect of the dehydrating agent is maintained under dilution with water.
  • Re-swelling ratio with ion-exchanged water [%] (Water retention amount [g / g] against ion-exchanged water after treatment with 1.0 wt% calcium chloride aqueous solution) / (Water retention amount against physiological saline [g / g] ⁇ 100 (2) The specific measuring method will be described later.
  • the re-swelling ratio (%) of the water-absorbent resin particles of the present invention with ion-exchanged water is 110 or less, more preferably 105 or less, from the viewpoint of the efficiency of dehydration treatment.
  • the lower limit is preferably as low as possible and is not particularly limited, but is preferably 80 or more from the viewpoint of balance with the absorption performance and productivity.
  • As means for reducing the re-swelling ratio widening the specific surface area of the particles, adjusting the balance between hydrophilicity and hydrophobicity inside or on the particles, increasing the anion concentration inside the particles, and a dehydrating agent It is considered that the surface area of the water absorbent resin particles after the treatment is kept small.
  • a hydrophobic substance is used in combination, or the heating temperature during drying when dehydrating from the hydrous gel is increased, Examples include reducing the average particle size. It is presumed that the presence of the hydrophobic substance on the surface of the absorbent resin particles prevents contact between the water absorbent resin particles and water existing around them, and as a result, it is considered that re-swelling of the gel is suppressed.
  • the gel permeation rate of the 1.0 wt% calcium chloride aqueous solution of the present invention is a value represented by the following formula, and the gel of the measurement sample swollen with physiological saline is 80 ml together with a part of the liquid used for the swelling. 20% physiological saline and calcium chloride mixed solution of 20 ml physiological saline and calcium chloride from the time (T3; second) flowing down between the swollen gels. It is calculated from the value obtained by subtracting the time (T4; seconds) in which the aqueous solution flows down in the absence of the measurement sample.
  • the gel permeation rate (ml / min) of the 1.0 wt% calcium chloride aqueous solution of the water absorbent resin particles of the present invention is 200 or more, more preferably 300 or more, and particularly preferably from the viewpoint of the efficiency of the dehydration treatment. It is 500 or more. The higher the upper limit, the more preferable it is not particularly limited, but from the viewpoint of performance balance with other physical properties and productivity, it is preferably 2300 or less, and more preferably 2000 or less.
  • the gel permeation rate of an aqueous 1.0 wt% calcium chloride solution solution is controlled by increasing the specific surface area of the particles and adjusting the balance between hydrophilicity and hydrophobicity inside or on the surface of the particles.
  • the absorption amount under load (g / g) of the water-absorbent resin particles of the present invention is preferably 19 or more. If it is less than 19, leakage is likely to occur during repeated use, which is not preferable. Further, the higher the upper limit value, the more preferable it is not particularly limited, but it is preferably 27 or less, more preferably 25 or less from the viewpoint of performance balance with other physical properties and productivity.
  • the absorption amount under load can be appropriately adjusted by the types and amounts of the crosslinking agent (b) and the surface crosslinking agent (e). Therefore, for example, when it is necessary to increase the absorption amount under load, it can be easily realized by increasing the amounts of the crosslinking agent (b) and the surface crosslinking agent (e) used.
  • the hygiene article of the present invention contains the water-absorbent resin particles of the present invention, and dehydration treatment of water from a used article is easy.
  • Examples of hygiene products include paper diapers, sanitary napkins, etc., but not limited to hygiene products, they are also used as absorbents and retainers for various aqueous liquids and as gelling agents. It is possible.
  • the method for manufacturing hygiene products and the like are the same as known methods (the methods described in JP-A-2003-225565, JP-A-2006-131767 and JP-A-2005-097569).
  • the water-absorbent resin particles may be used alone as the absorber, or may be used together with other materials as the absorber.
  • other materials include fibrous materials.
  • the structure and manufacturing method of the absorbent when used together with the fibrous material are the same as known ones (JP 2003-225565 A, JP 2006-131767 A, JP 2005-097569 A, etc.). is there.
  • the weight ratio of the water-absorbent resin particles to the fibers is preferably 30/70 to 90/10, and more preferably Is 40/60 to 70/30.
  • the fibrous material include cellulosic fibers, organic synthetic fibers, and a mixture of cellulosic fibers and organic synthetic fibers.
  • the method for treating a hygienic article of the present invention is a method for treating a used hygiene article containing water-absorbent resin particles, wherein the step of pulverizing the used hygiene article (hereinafter, referred to as "crushing step”).
  • A) a step of dehydrating the water-absorbent resin particles contained in the hygiene article or the crushed hygiene article with a dehydrating agent (hereinafter referred to as a dehydration step), and mixing the pulverized and dehydrated hygiene article with water. It includes a step of transporting to a solid-liquid processing apparatus (hereinafter referred to as "transporting step”).
  • the hygiene article may further include pulp fibers.
  • the crushing process is a process of crushing sanitary goods to obtain a crushed product.
  • a known crusher or crusher can be used.
  • a disposer type crusher used in a food waste crusher (a sanitary article is blown to a wall surface by a high-speed rotating turntable, A fixed type or variable type hammer and a fixed blade on the wall), a cutter mill, a single-axis type crusher, a twin-axis type crusher, a coaxial type crusher, a hammer type crusher, a ball mill, etc.
  • the hygiene products include plastic sheets, non-woven fabrics, and elastic materials, a disposer type crusher or a cutter mill that cuts with a blade while rotating at high speed is particularly suitable.
  • the crushed product of sanitary goods may be an aqueous suspension.
  • a method for obtaining an aqueous suspension there are a method of swelling hygiene products by adding water and then pulverizing, a method of pulverizing by adding water while pulverizing, and a method of adding water after pulverizing. From the viewpoint of reducing the load, a method of swelling the sanitary article by adding water and then pulverizing is preferred.
  • a suitable range of the size of the pulverized product of the sanitary article after pulverization depends on the separation / collection method by the solid-liquid separation device described later, but from the viewpoint of transportability in a water stream, the length of one piece of the sanitary article is preferable. Is 100 mm or less.
  • the size of the crushed product can be appropriately adjusted depending on the type of the crusher or the crusher described above, the processing conditions, and the like.
  • the sanitary goods may be crushed as they are, or the absorbent body containing the water-absorbent resin particles may be taken out from the sanitary goods and crushed.
  • the dehydration step is a step of dehydrating the water-absorbent resin particles contained in the sanitary goods or crushed sanitary goods with a dehydrating agent.
  • a dehydrating agent By this dehydration treatment, the water absorbing ability of the water absorbent resin particles is reduced, and the water content and volume of the water absorbent resin particles are reduced. As a result, the gel elasticity of the water absorbent resin particles is improved, and the separation and recovery efficiency is improved.
  • the dehydration step in the present invention includes not only the step of dehydrating the water-absorbent resin particles with a dehydrating agent but also the step of simply adding the dehydrating agent without actually causing the dehydration phenomenon.
  • the dehydrating agent in the present invention is not particularly limited as long as it is a compound having dehydrating performance, and known dehydrating agents include water-soluble polyvalent metal compounds, strong acids and the like.
  • the water-soluble polyvalent metal compound forms a chelate salt with a carboxyl group, or a carboxyl group ion, or by converting a carboxyl group ion to a carboxyl group by a strong acid, the water-absorbent resin particles have a As the difference in ion concentration decreases, the difference in osmotic pressure also decreases, resulting in dehydration from inside the water-absorbent resin particles.
  • the dehydrating agent is preferably a water-soluble polyvalent metal compound from the viewpoint of dehydration efficiency and handling.
  • the water-soluble polyvalent metal compound is an element having a valence of 2 or more in the periodic table, and forms a carboxyl group or a chelate salt with a carboxyl group ion after dissolving in water or reacting with water. If so, there is no particular limitation.
  • the divalent metal compound include polyvalent metal compounds containing alkaline earth metals such as magnesium, calcium, strontium and barium, and polyvalent metal compounds containing transition metals such as iron, nickel, copper and zinc.
  • the trivalent metal include polyvalent metal compounds containing metals such as boron, aluminum and gallium.
  • the polyvalent metal compound even if non-hydrated, monohydrate, dihydrate, trihydrate, tetrahydrate, pentahydrate, hexahydrate, heptahydrate It may be a hydrate such as a monohydrate, an octahydrate or a nonahydrate. These dehydrating agents may be used alone or in combination of two or more kinds.
  • the “water-soluble polyvalent metal compound” refers to a polyvalent metal compound having a solubility in water at 20 ° C. of 1 mg / ml or more, preferably 10 mg / ml or more.
  • water-soluble polyvalent metal compounds containing magnesium include magnesium sulfate, magnesium nitrate, magnesium chloride, magnesium bromide, magnesium iodide, magnesium perchlorate, magnesium permanganate, magnesium acetate and the like.
  • Examples of the water-soluble polyvalent metal compound containing calcium include calcium oxide, calcium peroxide, calcium hydroxide, calcium fluoride, calcium chloride, calcium bromide, calcium iodide, calcium hydride, calcium carbide, calcium phosphide, and carbonic acid.
  • a divalent water-soluble polyvalent metal compound is preferable, more preferably a water-soluble polyvalent metal compound containing magnesium and a water-soluble polyvalent metal compound containing calcium, from the viewpoint of improving the dehydration property.
  • Preferred are calcium chloride, calcium oxide, calcium acetate, and calcium hypochlorite.
  • the method of treating with a dehydrating agent is not particularly limited as long as it is a method in which the water-absorbent resin particles in the sanitary article come into contact with the dehydrating agent, but a solid dehydrating agent may be added to the sanitary article, or An aqueous solution may be added.
  • sanitary goods treated with a dehydrating agent may be swollen with water in advance and then added with the dehydrating agent, or water may be added after adding the dehydrating agent.
  • the apparatus for treating with a dehydrating agent any apparatus capable of mixing a hygiene article and a dehydrating agent may be used, and may be treated with the above-mentioned pulverizer and crusher, or may be separately treated with a stirring treatment tank. May be.
  • the amount of the dehydrating agent used in the dehydrating step depends on the type of the dehydrating agent used, but is preferably 0.1% or more, more preferably 1.0% or more, based on the dry weight of the water absorbent resin particles. , And more preferably 3.0% or more.
  • the amount of the dehydrating agent is small, the water separation rate of the water-absorbent resin particles decreases, and the separation and recovery efficiency decreases.
  • the step of pulverizing the hygiene article and the step of dehydrating the hygiene article or the water-absorbent particles contained in the pulverized hygiene article with the dehydrating agent can be carried out sequentially or simultaneously. ..
  • the specific order of the processing steps is shown below. Arrows indicate order. (1) Step of crushing sanitary goods ⁇ Step of dehydrating water-absorbent resin particles contained in the crushed sanitary goods with a dehydrating agent ⁇ Mixing crushed and dehydrated sanitary goods with water into a solid-liquid treatment device The process of transporting.
  • the transportation process is a process in which the crushed and dehydrated sanitary goods are mixed with water and transported to the downstream solid-liquid treatment device.
  • the hygiene product crush preferably an aqueous suspension, is transported by water supply to the solid-liquid treatment device by means of a water supply means.
  • the transportation means in the transportation process can be transported to the solid-liquid treatment device by a pump method or a natural flow-down method, but the crushed and dehydrated sanitary ware is passed through pipes or hoses to the solid-liquid separation device by water flow. It is preferably shipped.
  • the types of pipes or hoses include copper pipes, lead pipes, iron pipes, hard polyvinyl chloride pipes, polyethylene pipes, hard vinyl chloride lining pipes, stainless pipes, white pipes, earth pipes, fire-resistant double-layer pipes, and the like.
  • solid-liquid treatment device a known solid-liquid separation treatment device can be used.
  • screen separation, precipitation separation, membrane separation, centrifugation and the like can be mentioned.
  • a disposer wastewater treatment system is mentioned as one of the preferred embodiments of the method for treating sanitary goods of the present invention.
  • Disposer wastewater treatment is a system that normally crushes raw garbage with a disposer attached to the sink drain of the kitchen and discharges it to the sewer or septic tank together with the drainage of water supply, which reduces waste and is excellent in hygiene and convenience.
  • This is a wastewater treatment system, and it is spreading widely especially in apartment houses.
  • it is important to reduce the water swelling property of the water-absorbent resin particles and prevent defective drainage and pipe clogging due to accumulation and adhesion in the drainage pipe.
  • the treatment method of the invention is preferable because it can solve such a problem.
  • the method for treating hygiene products of the present invention is such that after the pulverized and dehydrated hygiene article is transported to the solid-liquid treatment device, the hygiene product containing the water-absorbent resin particles pulverized and dehydrated by the solid-liquid separation device is recovered.
  • the recovered hygiene product obtained by the method for treating hygiene products of the present invention has a feature of having a low water content, not only the combustion efficiency during incineration treatment is excellent, but it can also be recycled as a solid fuel or the like. .. Therefore, the present invention includes a method for producing a sanitary article recovery product and a solid fuel obtained by the method for treating a hygiene article. When recycled as the solid fuel, it is preferable to further dry the collected sanitary goods.
  • ⁇ Measurement method of water retention amount for physiological saline 1.00 g of the measurement sample was put into a tea bag (length 20 cm, width 10 cm) made of a nylon net having an opening of 63 ⁇ m (JIS Z8801-1: 2006), and in 1,000 ml of physiological saline (saline concentration 0.9%). It was soaked for 1 hour without stirring and then pulled up and hung for 15 minutes to drain water. Then, each tea bag was put in a centrifuge, spin-dried at 150 G for 90 seconds to remove excess physiological saline, and the weight (h1) including the tea bag was measured to determine the water retention amount from the following formula.
  • Water separation rate (%) (1-1.0 wt% water retention after treatment with calcium chloride aqueous solution) / (water retention relative to physiological saline) x 100
  • Re-swelling ratio with ion-exchanged water [%] (Water retention amount [g / g] for ion-exchanged water after treatment with 1.0 wt% calcium chloride aqueous solution) / (Water retention amount for physiological saline [g / g]) ⁇ ⁇ 100
  • ⁇ Measurement method of absorption under load Measurement by sieving in a range of 250 to 500 ⁇ m using a standard sieve in a cylindrical plastic tube (inner diameter: 25 mm, height: 34 mm) having a nylon net with an opening of 63 ⁇ m (JIS Z8801-1: 2006) attached to the bottom surface. 0.16 g of the sample was weighed, and the cylindrical plastic tube was placed vertically to prepare a measurement sample on the nylon net so that the measurement sample had a substantially uniform thickness, and then a weight (weight: 310.6 g, external Diameter: 24.5 mm,) was mounted.
  • ⁇ Method for measuring gel permeation rate of 1.0 wt% calcium chloride aqueous solution It measured by the following operations using the instrument shown in FIG. 1 and FIG. A swollen gel particle 2 was prepared by immersing 0.32 g of the measurement sample in 150 ml of physiological saline 1 (saline concentration 0.9%) for 30 minutes. Then, a vertically standing cylinder 3 ⁇ diameter (inner diameter) 25.4 mm, length 40 cm, graduation line 4 and graduation line 5 are provided at a position of 60 ml and 40 ml from the bottom, respectively.
  • the cock 7 was closed in a filtration cylindrical tube having a wire mesh 6 (opening 106 ⁇ m, JIS Z8801-1: 2006) and an openable / closable cock 7 (inner diameter of the liquid passage portion was 5 mm). .. Of the physiological saline solution used for the preparation of the measurement sample, 80 ml of the supernatant was discarded, the remaining swollen gel particles 2 were transferred together with the physiological saline solution, and 80 ml of calcium chloride solution was poured into the cylinder 3 to obtain the swollen gel.
  • a circular wire mesh 8 (opening 150 ⁇ m, diameter 25 mm) having a pressure shaft 9 (weight 22 g, length 47 cm) that is vertically bonded to the wire mesh surface is contacted with the wire mesh and the swollen gel particles. Then, the weight 10 (88.5 g) was placed on the pressure shaft 9 and left for 1 minute. Subsequently, the cock 7 is opened, and the time (T3; seconds) required for the liquid level in the filtration cylindrical tube to change from the 60 ml scale line 4 to the 40 ml scale line 5 is measured, and the gel flow rate (ml / min) is calculated from the following formula. I asked.
  • Example 1 Water-soluble vinyl monomer (a1) ⁇ acrylic acid ⁇ 157 parts (2.18 mol part), internal crosslinking agent (b) ⁇ pentaerythritol triallyl ether ⁇ 0.6305 part (0.0024 mol part) And 344.65 parts of deionized water were maintained at 3 ° C. with stirring and mixing.
  • Nitrogen was introduced into this mixture to adjust the amount of dissolved oxygen to 1 ppm or less, and then 0.63 parts of a 1% aqueous hydrogen peroxide solution, 1.1774 parts of a 2% aqueous ascorbic acid solution and 2% of 2,2'-azobis [ 2-Methyl-N- (2-hydroxyethyl) -propionamide] aqueous solution (2.355 parts) was added and mixed to initiate polymerization. After the temperature of the mixture reached 90 ° C., the mixture was polymerized at 90 ⁇ 2 ° C. for about 5 hours to obtain a hydrogel (1).
  • this hydrogel (1) was subdivided into about 1 mm square pieces with scissors, and 128.42 parts of 48.5% sodium hydroxide aqueous solution was added and mixed. Then, using a mincing machine (12VR-400K manufactured by ROYAL) having a perforated plate diameter of 16 mm, at a gel temperature of 80 ° C., add 0.10 parts of the hydrophobic substance (c-1) ⁇ Mg stearate ⁇ to the gel four times. After kneading and shredding, it was dried with a ventilation band dryer ⁇ 150 ° C., wind speed 2 m / sec ⁇ to obtain a dried body.
  • a mincing machine (12VR-400K manufactured by ROYAL) having a perforated plate diameter of 16 mm, at a gel temperature of 80 ° C.
  • the dried product was crushed with a juicer mixer (OSTERIZER BLENDER manufactured by Oster Co.), and then adjusted to a particle size range of 710 to 150 ⁇ m, to obtain dried particles.
  • the weight average particle diameter of the dried particles at this time was 392 ⁇ m.
  • a juicer mixer OEM BLENDER manufactured by Oster Co.
  • the mixture was allowed to stand at 150 ° C. for 30 minutes for surface cross-linking to obtain water-absorbent resin particles (P-1).
  • Example 2 Water-absorbent resin particles (P-2) were obtained in the same manner as in Example 1 except that the gel temperature was changed from 80 ° C to 120 ° C.
  • Example 3 Water-absorbent resin particles (P-3) were obtained in the same manner as in Example 1 except that the gel temperature was changed from 80 ° C to 40 ° C.
  • Example 4 Water-absorbent resin particles (P-4) were obtained in the same manner as in Example 1 except that the weight average particle diameter of the dried particles was changed from 392 ⁇ m to 200 ⁇ m.
  • Example 5 502.27 parts of the hydrogel (1) was subdivided into about 1 mm square with scissors, and 128.42 parts of 48.5% sodium hydroxide aqueous solution was added and mixed. Subsequently, using a mincing machine (12VR-400K manufactured by ROYAL) having a perforation diameter of 16 mm, after kneading and shredding four times, it was dried with a ventilation band dryer ⁇ 150 ° C., wind speed 2 m / sec ⁇ to obtain a dried body. .. The dried product was pulverized with a juicer mixer (OSTERIZER BLENDER manufactured by Oster), and then the dried product particles were adjusted to have a particle size range of 710 to 150 ⁇ m.
  • a juicer mixer OSTERIZER BLENDER manufactured by Oster
  • Example 6 502.27 parts of the hydrogel (1) was subdivided into about 1 mm square with scissors, and 128.42 parts of 48.5% sodium hydroxide aqueous solution was added and mixed. Subsequently, using a mincing machine (12VR-400K manufactured by ROYAL) having a perforation diameter of 16 mm, after kneading and shredding four times, it was dried with a ventilation band dryer ⁇ 150 ° C., wind speed 2 m / sec ⁇ to obtain a dried body. .. The dried product was pulverized with a juicer mixer (OSTERIZER BLENDER manufactured by Oster), and then the dried product particles were adjusted to have a particle size range of 710 to 150 ⁇ m.
  • a juicer mixer OSTERIZER BLENDER manufactured by Oster
  • Example 7 Water-absorbent resin particles (P-7) were obtained in the same manner as in Example 5, except that 0.4 part of the inorganic powder was not added.
  • Example 8 Water-absorbent resin particles (P-8) were obtained in the same manner as in Example 5, except that the amount of the hydrophobic substance (c-2) was changed from 0.02 part to 0.04 part.
  • Example 9 Water-absorbent resin particles (P-9) were obtained in the same manner as in Example 5, except that the amount of the hydrophobic substance (c-2) was changed from 0.02 part to 0.10 part.
  • Example 10 ⁇ Example 10> Implemented except that 0.10 part of the hydrophobic substance (c-1) was changed to 0.15 part of the hydrophobic substance (c-3) ⁇ sucrose stearic acid monoester ⁇ and 4 times kneading was changed to 2 times kneading.
  • Water-absorbent resin particles (P-10) were obtained in the same manner as in Example 1.
  • Example 11 Except for changing the subdivision into about 1 mm square with scissors into about 5 mm square, and changing 0.10 part of the hydrophobic substance (c-1) to 0.15 part of the hydrophobic substance (c-3), Water-absorbent resin particles (P-11) were obtained in the same manner as in Example 1.
  • Example 12 Same as Example 1 except that the diameter of the perforated plate 16 mm was changed to 8 mm, and 0.10 part of the hydrophobic substance (c-1) was changed to 0.15 part of the hydrophobic substance (c-3). Water-absorbent resin particles (P-12) were obtained.
  • Comparative water absorbent resin particles (H-1) were obtained in the same manner as in Example 1 except that the hydrophobic substance (c-1) was not added.
  • Comparative Example 2 A hydrogel subdivided into about 1 mm square was kneaded with a mincing machine (ROYAL's 12VR-400K) without being shredded and dried with a ventilation dryer ⁇ 150 ° C, wind speed 2 m / sec ⁇ and dried. Comparative water absorbing resin particles (H-2) were obtained in the same manner as in Example 1 except that the body was obtained.
  • a mincing machine ROYAL's 12VR-400K
  • Water-absorbent resin particles (H-6) were obtained in the same manner as in Example 1, except that the surface crosslinking temperature of 150 ° C was changed to 90 ° C.
  • ⁇ Preparation of hygiene products 100 parts of hydrophilic fibers (fluff pulp) and 100 parts of water-absorbent resin particles (water-absorbent resin particles obtained in Examples and Comparative Examples) were mixed by an air flow type mixing device (pad former) to form a mixture. After this was obtained, this mixture was uniformly laminated on an acrylic plate (thickness: 4 mm) so that the basis weight was 500 g / m 2, and pressed at a pressure of 5 kg / cm 2 for 30 seconds to obtain an absorber. This absorbent body was cut into 10 cm ⁇ 10 cm squares, and a water-permeable sheet (unit weight: 15.5 g / m 2 , Advantech, filter paper No.
  • a hygiene article was prepared by disposing a polyethylene sheet (S-1) (polyethylene film UB-1 manufactured by Tama Poly Co., Ltd.) as an impermeable sheet on the back surface and a nonwoven fabric (S-2) as a nonwoven fabric layer on the front surface.
  • S-1 polyethylene film UB-1 manufactured by Tama Poly Co., Ltd.
  • S-2 nonwoven fabric
  • the swollen absorber was placed in a tea bag (15 cm in length, 15 cm in width) made of a nylon net having an opening of 63 ⁇ m (JIS Z8801-1: 2006), and the tea bag was placed in 1,000 ml of a 1.0 wt% calcium chloride aqueous solution. After soaking without stirring for 5 minutes, pull up, put in a centrifuge, spin-dry for 90 seconds at 150 G to remove excess calcium chloride aqueous solution, and measure the weight including the tea bag (h6; g) The dehydration rate of the absorber is calculated from The temperatures of the physiological saline solution, the calcium chloride aqueous solution and the measurement atmosphere used are 25 ° C. ⁇ 2 ° C.
  • (H7; g) is the weight of the absorbent (h7; g) swollen after the absorbent was prepared in the same manner and allowed to stand for 5 hours, then the nonwoven fabrics (S-1) and (S-2) were removed from the hygiene article. ) Is the weight when measured.
  • Absorber dehydration rate (%) [1- ⁇ (h6)-(h7) ⁇ / (h5)] ⁇ 100
  • the water-absorbent resin particles of the present invention which can be easily dehydrated have an improved water separation rate as compared with the water-absorbent resin particles of Comparative Example. Further, in the evaluation of the water separation rate of the absorbent body using the present water-absorbent resin particles, it is found that the higher the water separation rate of the water-absorbent resin particles, the higher the water separation rate of the absorbent body. This result indicates that the absorbent body using the water absorbent resin particles having a high water separation rate has a reduced water content after the dehydration treatment of the swollen absorbent body, and can reduce the total weight per absorbent body.
  • the labor during transportation can be reduced, and the energy used for incineration at the time of incineration treatment can be suppressed, so that the environmental load can be reduced.
  • the absorbent article By applying the water-absorbent resin particles of the present invention that are easily dehydrated to various absorbent articles including hygiene products, while satisfying the necessary absorption performance during use, after a predetermined dehydration treatment after use, the absorbent article Since the water content can be easily reduced, disposable diapers (children's paper diapers and adult paper diapers, etc.), napkins (sanitary napkins, etc.), paper towels, pads (incontinence pads, surgical underpads, etc.), and pets It is suitable for use in hygiene products such as sheets (pet urine absorption sheets), and is most suitable for disposable diapers.

Abstract

Provided are: water-absorbent resin particles which have excellent water-absorbent characteristics in normal use and are easily dehydratable after use; a production method thereof; and a method for treating a sanitary article. The present invention relates to water-absorbent resin particles, a sanitary article including the same, and a method for treating the sanitary article, the water-absorbent resin particles containing a cross-linked polymer (A) having, as essential constituent units: a water-soluble vinyl monomer (a1) and/or a vinyl monomer (a2) which becomes the water-soluble vinyl monomer (a1) through hydrolysis; and an internal cross-linking agent (b), wherein the water separation ratio represented by the following equation is 70% or more. Water separation ratio [%] = {1-(water retaining amount after treating with 1.0 wt% of calcium chloride aqueous solution [g/g])/(water retaining amount with respect to physiological saline [g/g])}×100

Description

脱水処理が容易な吸水性樹脂粒子及びその製造方法Water-absorbent resin particles that are easily dehydrated and method for producing the same
　本発明は、脱水処理が容易な吸水性樹脂粒子及びその製造方法に関する。 The present invention relates to water-absorbent resin particles that can be easily dehydrated and a method for producing the same.
　近年、衛生用品の使用量が増加するにつれて、使用後の衛生用品のごみ処理が深刻な問題となりつつある。衛生用品、特に紙おむつは少子高齢化時代に欠かせない用品として、急激に普及し、その消費は急増している。使用後の衛生用品のごみ処理に関し、紙おむつなどは通常、焼却処理されているが、おむつ中の水分の割合は約８割近くであるため、焼却には大きな燃焼エネルギーが必要となる。この処理方法は焼却炉自体に大きな負荷がかかり、結果として焼却炉の寿命を短くする原因に繋がるだけではなく、大気汚染や地球の温暖化に繋がり、環境に負荷をかける要因にもなるため改善が強く望まれている。 Recently, as the amount of sanitary goods used increases, the disposal of sanitary goods after use is becoming a serious problem. Hygiene products, especially disposable diapers, have rapidly spread as consumption goods indispensable in the age of declining birthrate and aging, and their consumption is increasing rapidly. Regarding disposal of hygiene products after use, paper diapers and the like are usually incinerated, but since the proportion of water in diapers is about 80%, incineration requires large combustion energy. This treatment method puts a heavy load on the incinerator itself, resulting in not only the cause of shortening the life of the incinerator, but also air pollution and global warming, which is also a factor that affects the environment and is therefore improved. Is strongly desired.
　使用後の衛生用品のごみ処理問題を解決するための手段がこれまでいくつか提案されている。例えば、石灰を用いることで、吸水性樹脂粒子と衛生用品の他部材を分離し回収するシステムに関する技術（特許文献１）、塩化カルシウム水溶液を用いることで吸水性樹脂粒子を脱水凝集させた後に、強酸と窒素含有塩基性化合物との塩を加えて凝集力を低下させ、その後の乾燥を容易にする技術（特許文献２）、使用済みの高吸水性ポリマーを多価金属塩水溶液で脱水処理した後、アルカリ金属塩水溶液で処理することで、高吸水性ポリマーの吸水分能力を回復させる技術（特許文献３）、パルプ繊維および高吸水性ポリマーを含む使用済み衛生用品からパルプ繊維を回収し、オゾン処理で高吸水性ポリマーを分解することで、衛生用品に再利用可能なリサイクルパルプを製造する技術（特許文献４）等が提案されている。 ❖ Several means have been proposed so far to solve the problem of waste disposal of sanitary goods after use. For example, a technique relating to a system for separating and collecting water-absorbent resin particles and other members of hygiene articles by using lime (Patent Document 1), after dehydrating and aggregating the water-absorbent resin particles by using an aqueous calcium chloride solution, A technique of adding a salt of a strong acid and a nitrogen-containing basic compound to reduce the cohesive force and facilitating subsequent drying (Patent Document 2), and a used superabsorbent polymer was dehydrated with a polyvalent metal salt aqueous solution. After that, by treating with an aqueous solution of an alkali metal salt, a technique for recovering the water absorption capacity of the superabsorbent polymer (Patent Document 3), recovering pulp fibers from used hygiene products containing pulp fibers and superabsorbent polymer, A technique (Patent Document 4) for producing recycled pulp that can be reused for sanitary products by decomposing a super absorbent polymer by ozone treatment has been proposed.
特開２００９－１８３８９３号公報JP, 2009-183893, A 特開２０１５－１２０８３４号公報JP, 2015-120834, A 特開２０１３－１９８８６２号公報JP, 2013-198862, A 特開２０１７－１９３８１９号公報JP, 2017-193819, A
　使用後の衛生用品のごみ処理問題に対して、使用済みの衛生用品に含まれる水分を効率的に除去できれば、焼却処理時の燃焼効率やリサイクル時の生産性が向上し、環境負荷が大幅に軽減されると期待できる。本発明の目的は、通常の使用時に良好な吸収特性を有し、かつ使用済みの衛生用品に含まれる水分の脱水処理が容易な吸水性樹脂粒子及びその製造方法を提供することである。 If the water contained in the used hygiene products can be efficiently removed in response to the waste disposal problem of the sanitary products after use, the combustion efficiency at the time of incineration and the productivity at the time of recycling will be improved, and the environmental load will be significantly increased. It can be expected to be reduced. It is an object of the present invention to provide water-absorbent resin particles having good absorption properties during normal use, and capable of easily dehydrating water contained in used hygiene products, and a method for producing the same.
　本発明は、水溶性ビニルモノマー（ａ１）及び／又は加水分解により水溶性ビニルモノマー（ａ１）となるビニルモノマー（ａ２）並びに内部架橋剤（ｂ）を必須構成単位とする架橋重合体（Ａ）を含有し、下記式（１）で示される離水率が７０％以上である脱水処理が容易な吸水性樹脂粒子及びこれを含む衛生用品である。
離水率［％］＝｛１－（１．０重量％塩化カルシウム水溶液処理後の保水量［ｇ／ｇ］）／（生理食塩水に対する保水量［ｇ／ｇ］）｝×１００　　　　（１）
　本発明はまた、上記吸水性樹脂粒子の製造方法であって、水溶性ビニルモノマー（ａ１）及び／又は加水分解により水溶性ビニルモノマー（ａ１）となるビニルモノマー（ａ２）並びに内部架橋剤（ｂ）を必須構成単位とする単量体組成物を重合して、架橋重合体（Ａ）を含有する含水ゲルを得る重合工程、架橋重合体（Ａ）の含水ゲルを細分する工程、細分した含水ゲルをゲル温度４０℃～１２０℃でさらに混練細断する工程、及び前記混練細断した含水ゲルを乾燥した後に粉砕して、吸水性樹脂粒子を得る工程を含む、上記吸水性樹脂粒子の製造方法である。
である。 The present invention relates to a crosslinked polymer (A) containing a water-soluble vinyl monomer (a1) and / or a vinyl monomer (a2) which becomes a water-soluble vinyl monomer (a1) by hydrolysis and an internal crosslinking agent (b) as essential constituent units. Water-absorbent resin particles containing water and having a water separation rate of 70% or more represented by the following formula (1), which is easy to be dehydrated, and hygiene products containing the same.
Water separation rate [%] = {1- (water retention amount after treatment with 1.0 wt% calcium chloride aqueous solution [g / g]) / (water retention amount against physiological saline [g / g])} × 100 (1)
The present invention also relates to the above-mentioned method for producing water-absorbent resin particles, which comprises a water-soluble vinyl monomer (a1) and / or a vinyl monomer (a2) which becomes a water-soluble vinyl monomer (a1) by hydrolysis and an internal cross-linking agent (b). Polymerization of a monomer composition containing a cross-linked polymer (A) as an essential structural unit to obtain a hydrogel containing the crosslinked polymer (A), a step of subdividing the hydrogel of the crosslinked polymer (A), and a subdivided hydrous Production of the above water-absorbent resin particles, including a step of further kneading and shredding the gel at a gel temperature of 40 ° C. to 120 ° C., and a step of drying and then pulverizing the kneaded and shredded hydrogel to obtain water-absorbent resin particles Is the way.
Is.
　本発明の脱水処理が容易な吸水性樹脂粒子（以下、単に、本発明の吸水性樹脂粒子ともいう。）は、脱水剤で処理した際に優れた離水性を示す。また、本発明の吸水性樹脂粒子を含む紙おむつ等の衛生用品は、使用時には紙おむつとして必要な吸収性能を満たしながら、使用後には多価金属塩水溶液等の脱水剤の添加により、吸水樹脂粒子の含水率を大幅に低下させることができ、容易に脱水処理することが可能である。従って、焼却処理時の燃焼効率やリサイクル時の生産性が向上し、環境負荷を低減することができる。 The water-absorbent resin particles of the present invention that can be easily dehydrated (hereinafter also simply referred to as water-absorbent resin particles of the present invention) exhibit excellent water separation properties when treated with a dehydrating agent. Further, hygiene articles such as paper diapers containing the water-absorbent resin particles of the present invention, while satisfying the required absorption performance as a paper diaper at the time of use, by the addition of a dehydrating agent such as a polyvalent metal salt aqueous solution after use, The water content can be significantly reduced, and dehydration treatment can be easily performed. Therefore, the combustion efficiency at the time of incineration and the productivity at the time of recycling are improved, and the environmental load can be reduced.
ゲル通液速度を測定するための濾過円筒管を模式的に表した断面図である。It is sectional drawing which represented typically the filtration cylindrical tube for measuring a gel flow rate. ゲル通液速度を測定するための加圧軸及びおもりを模式的に表した斜視図である。FIG. 3 is a perspective view schematically showing a pressurizing shaft and a weight for measuring a gel passage rate.
　本発明の吸水性樹脂粒子は、水溶性ビニルモノマー（ａ１）及び／又は加水分解により水溶性ビニルモノマー（ａ１）となるビニルモノマー（ａ２）並びに内部架橋剤（ｂ）を必須構成単位とする架橋重合体（Ａ）を含有する吸水性樹脂粒子である。 The water-absorbent resin particles of the present invention are crosslinked with the water-soluble vinyl monomer (a1) and / or the vinyl monomer (a2) that becomes a water-soluble vinyl monomer (a1) by hydrolysis and an internal crosslinking agent (b) as essential constituent units. Water-absorbent resin particles containing the polymer (A).
　本発明における水溶性ビニルモノマー（ａ１）としては特に限定はなく、公知のモノマー、例えば、特許第３６４８５５３号公報の０００７～００２３段落に開示されている少なくとも１個の水溶性置換基とエチレン性不飽和基とを有するビニルモノマー（例えばアニオン性ビニルモノマー、非イオン性ビニルモノマー及びカチオン性ビニルモノマー）、特開２００３－１６５８８３号公報の０００９～００２４段落に開示されているアニオン性ビニルモノマー、非イオン性ビニルモノマー及びカチオン性ビニルモノマー並びに特開２００５－７５９８２号公報の００４１～００５１段落に開示されているカルボキシ基、スルホ基、ホスホノ基、水酸基、カルバモイル基、アミノ基及びアンモニオ基からなる群から選ばれる少なくとも１種を有するビニルモノマーが使用できる。 The water-soluble vinyl monomer (a1) in the present invention is not particularly limited, and known monomers such as at least one water-soluble substituent and an ethylenic vinyl group disclosed in paragraphs 0007 to 0023 of Japanese Patent No. 3648553 are used. Vinyl monomers having a saturated group (for example, anionic vinyl monomers, nonionic vinyl monomers and cationic vinyl monomers), anionic vinyl monomers and nonionic compounds disclosed in paragraphs 0009 to 0024 of JP-A-2003-165883. Vinyl monomer and cationic vinyl monomer, and selected from the group consisting of carboxy group, sulfo group, phosphono group, hydroxyl group, carbamoyl group, amino group and ammonio group disclosed in paragraphs 0041 to 0051 of JP-A-2005-75982. Vinyl monomers having at least one of
　加水分解により水溶性ビニルモノマー（ａ２）となるビニルモノマー（ａ２）（以下、加水分解性ビニルモノマー（ａ２）ともいう。）は特に限定はなく公知（たとえば、特許第３６４８５５３号公報の００２４～００２５段落に開示されている加水分解により水溶性置換基となる加水分解性置換基を少なくとも１個有するビニルモノマー、特開２００５－７５９８２号公報の００５２～００５５段落に開示されている少なくとも１個の加水分解性置換基（１，３－オキソ－２－オキサプロピレン（－ＣＯ－Ｏ－ＣＯ－）基、アシル基及びシアノ基等）を有するビニルモノマー）のビニルモノマー等が使用できる。なお、水溶性ビニルモノマーとは、２５℃の水１００ｇに少なくとも１００ｇ溶解する性質を持つビニルモノマーを意味する。また、加水分解性とは、５０℃の水及び必要により触媒（酸又は塩基等）の作用により加水分解され水溶性になる性質を意味する。加水分解性ビニルモノマーの加水分解（ａ２）は、重合中、重合後及びこれらの両方のいずれでもよいが、得られる吸水性樹脂粒子の分子量の観点等から重合後が好ましい。 The vinyl monomer (a2) (hereinafter, also referred to as a hydrolyzable vinyl monomer (a2)) that becomes a water-soluble vinyl monomer (a2) by hydrolysis is not particularly limited and is publicly known (for example, 0024 to 0025 of Japanese Patent No. 3648553). A vinyl monomer having at least one hydrolyzable substituent that becomes a water-soluble substituent by hydrolysis disclosed in the paragraph, and at least one hydrolyzate disclosed in paragraphs 0052 to 0055 of JP 2005-75982 A. A vinyl monomer having a decomposable substituent (a vinyl monomer having a 1,3-oxo-2-oxapropylene (—CO—O—CO—) group, an acyl group, a cyano group, 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" means a property of being hydrolyzed by being hydrolyzed by the action of water at 50 ° C and, if necessary, a catalyst (acid or base etc.). The hydrolysis (a2) of the hydrolyzable vinyl monomer may be carried out during the polymerization, after the polymerization, or both of them, but the polymerization is preferable from the viewpoint of the molecular weight of the water-absorbent resin particles to be obtained.
　これらのうち、吸収特性の観点等から、水溶性ビニルモノマー（ａ１）が好ましい。水溶性ビニルモノマー（ａ１）としては、好ましくはアニオン性ビニルモノマー、より好ましくはカルボキシ（塩）基、スルホ（塩）基、アミノ基、カルバモイル基、アンモニオ基又はモノ－、ジ－若しくはトリ－アルキルアンモニオ基を有するビニルモノマーである。これらのなかでは、より好ましくはカルボキシ（塩）基又はカルバモイル基を有するビニルモノマー、さらに好ましくは（メタ）アクリル酸（塩）及び（メタ）アクリルアミド、特に好ましくは（メタ）アクリル酸（塩）、最も好ましくはアクリル酸（塩）である。 Of these, the water-soluble vinyl monomer (a1) is preferable from the viewpoint of absorption characteristics. The water-soluble vinyl monomer (a1) is preferably an anionic vinyl monomer, more preferably a carboxy (salt) group, a sulfo (salt) group, an amino group, a carbamoyl group, an ammonio group or a mono-, di- or tri-alkyl group. It is a vinyl monomer having an ammonio group. Among these, more preferably a vinyl monomer having a carboxy (salt) group or a carbamoyl group, further preferably (meth) acrylic acid (salt) and (meth) acrylamide, particularly preferably (meth) acrylic acid (salt), Most preferably, it is acrylic acid (salt).
　なお、「カルボキシ（塩）基」は「カルボキシ基」又は「カルボキシレート基」を意味し、「スルホ（塩）基」は「スルホ基」又は「スルホネート基」を意味する。また、（メタ）アクリル酸（塩）はアクリル酸、アクリル酸塩、メタクリル酸又はメタクリル酸塩を意味し、（メタ）アクリルアミドはアクリルアミド又はメタクリルアミドを意味する。また、塩としては、アルカリ金属（リチウム、ナトリウム及びカリウム等）塩、アルカリ土類金属（マグネシウム及びカルシウム等）塩又はアンモニウム（ＮＨ４）塩等が含まれる。これらの塩のうち、吸収特性の観点等から、アルカリ金属塩及びアンモニウム塩が好ましく、さらに好ましくはアルカリ金属塩、特に好ましくはナトリウム塩である。 In addition, a "carboxy (salt) group" means a "carboxy group" or a "carboxylate group", and a "sulfo (salt) group" means a "sulfo group" or a "sulfonate group". Further, (meth) acrylic acid (salt) means acrylic acid, acrylic acid salt, methacrylic acid or methacrylic acid salt, and (meth) acrylamide means acrylamide or methacrylamide. Examples of the salt include alkali metal (lithium, sodium and potassium etc.) salts, alkaline earth metal (magnesium and calcium etc.) salts, ammonium (NH 4 ) salts and the like. Among these salts, alkali metal salts and ammonium salts are preferable, alkali metal salts are more preferable, and sodium salts are particularly preferable, from the viewpoint of absorption characteristics.
　水溶性ビニルモノマー（ａ１）としてアクリル酸やメタクリル酸等の酸基含有モノマーを用いる場合、吸水性能や残存モノマーの観点から、酸基含有モノマーの一部が塩基で中和されていることが好ましい。中和する塩基としては、水酸化ナトリウム、水酸化カリウム等のアルカリ金属水酸化物や、炭酸ナトリウム、炭酸水素ナトリウム、炭酸カリウム等のアルカリ金属炭酸塩を使用できる。中和は、吸水性樹脂粒子の製造において、重合前、重合中、重合後及びこれらの両方のいずれで行っても良いが、例えば、重合前に酸基含有モノマーを中和する方法や重合後に酸基含有ポリマーを含水ゲルの状態で中和する等の方法が好ましい例として例示される。 When an acid group-containing monomer such as acrylic acid or methacrylic acid is used as the water-soluble vinyl monomer (a1), it is preferable that a part of the acid group-containing monomer is neutralized with a base from the viewpoint of water absorption performance and residual monomer. .. As the base to be neutralized, alkali metal hydroxides such as sodium hydroxide and potassium hydroxide and alkali metal carbonates such as sodium carbonate, sodium hydrogen carbonate and potassium carbonate can be used. Neutralization, in the production of the water-absorbent resin particles, before the polymerization, during the polymerization, after the polymerization may be performed any of these, for example, a method of neutralizing the acid group-containing monomer before the polymerization or after the polymerization. A preferable example is a method of neutralizing the acid group-containing polymer in the state of a water-containing gel.
　また、前記酸基含有モノマーを用いる場合の酸基の中和度は、５０～８０モル％であることが好ましい。中和度が５０モル％未満の場合、得られる含水ゲル重合体の粘着性が高くなり、製造時及び使用時の作業性が悪化する場合がある。更に得られる吸水性樹脂粒子の保水量が低下する場合がある。一方、中和度が８０％を超える場合、得られた樹脂のｐＨが高くなり人体の皮膚に対する安全性が懸念される場合がある。 The degree of neutralization of the acid group when using the acid group-containing monomer is preferably 50 to 80 mol%. When the degree of neutralization is less than 50 mol%, the resulting hydrogel polymer may have high tackiness, which may deteriorate workability during production and use. Further, the water retention amount of the resulting water-absorbent resin particles may decrease. On the other hand, when the degree of neutralization exceeds 80%, the pH of the obtained resin becomes high, and there is a concern about the safety of the skin of human body.
　水溶性ビニルモノマー（ａ１）又は加水分解性ビニルモノマー（ａ２）のいずれかを構成単位とする場合、それぞれ単独で構成単位としてもよく、また、必要により２種以上を構成単位としてもよい。また、水溶性ビニルモノマー（ａ１）及び加水分解性ビニルモノマー（ａ２）を構成単位とする場合も同様である。また、水溶性ビニルモノマー（ａ１）及び加水分解性ビニルモノマー（ａ２）を構成単位とする場合、これらの含有モル比（ａ１／ａ２）は、７５／２５～９９／１が好ましく、さらに好ましくは８５／１５～９５／５、特に好ましくは９０／１０～９３／７、最も好ましくは９１／９～９２／８である。この範囲であると、吸収性能がさらに良好となる。 When either the water-soluble vinyl monomer (a1) or the hydrolyzable vinyl monomer (a2) is used as the constitutional unit, each may be a constitutional unit independently, or if necessary, two or more types may be constitutional units. The same applies to the case where the water-soluble vinyl monomer (a1) and the hydrolyzable vinyl monomer (a2) are used as the constituent units. When the water-soluble vinyl monomer (a1) and the hydrolyzable vinyl monomer (a2) are used as constituent units, the molar ratio (a1 / a2) of these is preferably 75/25 to 99/1, and more preferably 85/15 to 95/5, particularly preferably 90/10 to 93/7, most preferably 91/9 to 92/8. Within this range, the absorption performance is further improved.
　架橋重合体（Ａ）の構成単位として、水溶性ビニルモノマー（ａ１）及び加水分解性ビニルモノマー（ａ２）の他に、これらと共重合可能なその他のビニルモノマー（ａ３）を構成単位とすることができる。 As the constitutional unit of the crosslinked polymer (A), in addition to the water-soluble vinyl monomer (a1) and the hydrolyzable vinyl monomer (a2), other vinyl monomer (a3) copolymerizable with them is used as the constitutional unit. You can
　共重合可能なその他のビニルモノマー（ａ３）としては特に限定はなく公知（たとえば、特許第３６４８５５３号公報の００２８～００２９段落に開示されている疎水性ビニルモノマー、特開２００３－１６５８８３号公報、特開２００５－７５９８２号公報の００５８段落に開示されているビニルモノマー）の疎水性ビニルモノマー等が使用でき、下記の(ｉ)～(ｉｉｉ)のビニルモノマー等が使用できる。
（ｉ）炭素数８～３０の芳香族エチレン性モノマー
　スチレン、α－メチルスチレン、ビニルトルエン及びヒドロキシスチレン等のスチレン、並びにビニルナフタレン及びジクロルスチレン等のスチレンのハロゲン置換体等。
（ｉｉ）炭素数２～２０の脂肪族エチレンモノマー
　アルケン［エチレン、プロピレン、ブテン、イソブチレン、ペンテン、ヘプテン、ジイソブチレン、オクテン、ドデセン及びオクタデセン等］；並びにアルカジエン［ブタジエン及びイソプレン等］等。
（ｉｉｉ）炭素数５～１５の脂環式エチレンモノマー
　モノエチレン性不飽和モノマー［ピネン、リモネン及びインデン等］；並びにポリエチレン性ビニル重合性モノマー［シクロペンタジエン、ビシクロペンタジエン及びエチリデンノルボルネン等］等。 The other copolymerizable vinyl monomer (a3) is not particularly limited and is well known (for example, the hydrophobic vinyl monomer disclosed in paragraphs 0028 to 0029 of Japanese Patent No. 3648553, JP-A-2003-165883, JP Hydrophobic vinyl monomers such as vinyl monomers disclosed in paragraph 0058 of Japanese Unexamined Patent Publication No. 2005-75982 can be used, and the following vinyl monomers (i) to (iii) can be used.
(I) Aromatic ethylenic monomer having 8 to 30 carbon atoms Styrene such as styrene, α-methylstyrene, vinyltoluene and hydroxystyrene, and halogen-substituted styrene such as vinylnaphthalene and dichlorostyrene.
(Ii) C2-C20 aliphatic ethylene monomers alkenes [ethylene, propylene, butene, isobutylene, pentene, heptene, diisobutylene, octene, dodecene, octadecene, etc.]; and alkadienes [butadiene, isoprene, etc.] and the like.
(Iii) C5-C15 alicyclic ethylene monomers, monoethylenically unsaturated monomers [pinene, limonene, indene, etc.]; and polyethylene vinyl polymerizable monomers [cyclopentadiene, bicyclopentadiene, ethylidene norbornene, etc.] and the like.
　その他のビニルモノマー（ａ３）を構成単位とする場合、その他のビニルモノマー（ａ３）単位の含有量（モル％）は、水溶性ビニルモノマー（ａ１）単位及び加水分解性ビニルモノマー（ａ２）単位のモル数に基づいて、０．０１～５が好ましく、さらに好ましくは０．０５～３、よりさらに好ましくは０．０８～２、特に好ましくは０．１～１．５である。なお、上述にもかかわらず、吸収特性の観点等から、その他のビニルモノマー（ａ３）単位の含有量が０モル％であることが最も好ましい。 When the other vinyl monomer (a3) is a constituent unit, the content (mol%) of the other vinyl monomer (a3) unit is the same as that of the water-soluble vinyl monomer (a1) unit and the hydrolyzable vinyl monomer (a2) unit. It is preferably 0.01 to 5, more preferably 0.05 to 3, still more preferably 0.08 to 2, and particularly preferably 0.1 to 1.5, based on the number of moles. Despite the above, it is most preferable that the content of the other vinyl monomer (a3) unit is 0 mol% from the viewpoint of absorption characteristics.
　内部架橋剤（ｂ）（以下、単に架橋剤（ｂ）ともいう）としては特に限定はなく公知（例えば、特許第３６４８５５３号公報の００３１～００３４段落に開示されているエチレン性不飽和基を２個以上有する架橋剤、水溶性置換基と反応し得る官能基を少なくとも１個有してかつ少なくとも１個のエチレン性不飽和基を有する架橋剤及び水溶性置換基と反応し得る官能基を少なくとも２個有する架橋剤、特開２００３－１６５８８３号公報の００２８～００３１段落に開示されているエチレン性不飽和基を２個以上有する架橋剤、エチレン性不飽和基と反応性官能基とを有する架橋剤及び反応性置換基を２個以上有する架橋剤、特開２００５－７５９８２号公報の００５９段落に開示されている架橋性ビニルモノマー並びに特開２００５－９５７５９号公報の００１５～００１６段落に開示されている架橋性ビニルモノマー）の架橋剤等が使用できる。これらの内、吸収性能等の観点から、エチレン性不飽和基を２個以上有する架橋剤が好ましく、更に好ましいのはトリアリルシアヌレート、トリアリルイソシアヌレート及び炭素数２～１０のポリオールのポリ（メタ）アリルエーテル、特に好ましいのはトリアリルシアヌレート、トリアリルイソシアヌレート、テトラアリロキシエタン及びペンタエリスリトールトリアリルエーテル、最も好ましいのはペンタエリスリトールトリアリルエーテルである。架橋剤（ｂ）は１種を単独で用いても、２種以上を併用してもよい。 The internal cross-linking agent (b) (hereinafter, also simply referred to as the cross-linking agent (b)) is not particularly limited and is publicly known (for example, the ethylenically unsaturated group disclosed in paragraphs 0031 to 0034 of Japanese Patent No. 3648553 is 2). At least one cross-linking agent, a cross-linking agent having at least one functional group capable of reacting with a water-soluble substituent and having at least one ethylenically unsaturated group, and a functional group capable of reacting with a water-soluble substituent. Cross-linking agent having two, cross-linking agent having two or more ethylenically unsaturated groups disclosed in paragraphs 0028 to 0031 of JP-A-2003-165883, and cross-linking having ethylenically unsaturated groups and reactive functional groups Agent and a cross-linking agent having two or more reactive substituents, the cross-linkable vinyl monomer disclosed in paragraph 0059 of JP-A-2005-75982, and the paragraphs 0015 to 0016 of JP-A-2005-95759. A cross-linking agent of cross-linkable vinyl monomer) can be used. Among these, a crosslinking agent having two or more ethylenically unsaturated groups is preferable from the viewpoint of absorption performance and the like, and more preferable are poly (poly (aryl) (triallyl cyanurate, triallyl isocyanurate, and polyol having 2 to 10 carbon atoms). (Meth) allyl ether, particularly preferred are triallyl cyanurate, triallyl isocyanurate, tetraallyloxyethane and pentaerythritol triallyl ether, most preferred is pentaerythritol triallyl ether. As the crosslinking agent (b), one type may be used alone, or two or more types may be used in combination.
　架橋剤（ｂ）単位の含有量（モル％）は、水溶性ビニルモノマー（ａ１）単位及び加水分解性ビニルモノマー（ａ２）単位の、その他のビニルモノマー（ａ３）を用いる場合は（ａ１）～（ａ３）の、合計モル数に基づいて、０．００１～５が好ましく、更に好ましくは０．００５～３、特に好ましくは０．０１～１である。この範囲であると、吸収性能が更に良好となる。 The content (mol%) of the crosslinking agent (b) unit is from (a1) to (a1) when the other vinyl monomer (a3) of the water-soluble vinyl monomer (a1) unit and the hydrolyzable vinyl monomer (a2) unit is used. Based on the total number of moles of (a3), it is preferably 0.001 to 5, more preferably 0.005 to 3, and particularly preferably 0.01 to 1. Within this range, the absorption performance will be further improved.
　本発明の吸水性樹脂粒子の製造方法は、前述した水溶性ビニルモノマー（ａ１）及び／又は加水分解性ビニルモノマー（ａ２）並びに内部架橋剤（ｂ）を必須構成単位とする単量体組成物を重合して、架橋重合体（Ａ）を含有する含水ゲルを得る重合工程、架橋重合体（Ａ）の含水ゲルを細分する工程、細分した含水ゲルをゲル温度４０℃～１２０℃でさらに混練細断する工程、及び前記混練細断した含水ゲルを乾燥した後粉砕して、吸水性樹脂粒子を得る工程を含む。 The method for producing water-absorbent resin particles of the present invention is a monomer composition containing the above-mentioned water-soluble vinyl monomer (a1) and / or hydrolyzable vinyl monomer (a2) and an internal crosslinking agent (b) as essential constituent units. Polymerization step to obtain a hydrogel containing the crosslinked polymer (A), a step of subdividing the hydrogel of the crosslinked polymer (A), and further kneading the subdivided hydrogel at a gel temperature of 40 ° C to 120 ° C. The method includes a step of shredding, and a step of drying and then crushing the kneaded shredded hydrogel to obtain water-absorbent resin particles.
　架橋重合体（Ａ）の製造方法としては、公知の溶液重合（断熱重合、薄膜重合及び噴霧重合法等；特開昭５５－１３３４１３号公報等）や、公知の懸濁重合法や逆相懸濁重合（特公昭５４－３０７１０号公報、特開昭５６－２６９０９号公報及び特開平１－５８０８号公報等）によって架橋重合体（Ａ）を含有する含水ゲル（架橋重合体と水とからなる。）を得ることができる。架橋重合体（Ａ）は、１種単独でも良いし、２種以上の混合物であっても良い。 Examples of the method for producing the crosslinked polymer (A) include known solution polymerization (adiabatic polymerization, thin film polymerization, spray polymerization, etc .; JP-A-55-133413, etc.), known suspension polymerization method, reverse phase suspension method, etc. A hydrogel containing a crosslinked polymer (A) (consisting of a crosslinked polymer and water) by turbid polymerization (Japanese Patent Publication No. 54-30710, Japanese Patent Application Laid-Open No. 56-26909, Japanese Patent Application Laid-Open No. 1-5808, etc.). .) Can be obtained. The crosslinked polymer (A) may be a single type or a mixture of two or more types.
　重合方法の内、好ましいのは溶液重合法であり、有機溶媒等を使用する必要がなく生産コスト面で有利なことから、特に好ましいのは水溶液重合法であり、保水量が大きく、且つ水可溶性成分量の少ない吸水性樹脂が得られ、重合時の温度コントロールが不要である点から、水溶液断熱重合法が最も好ましい。 Among the polymerization methods, the solution polymerization method is preferable, and since it is advantageous in terms of production cost that it is not necessary to use an organic solvent or the like, particularly preferable is the aqueous solution polymerization method, which has a large water retention amount and is water-soluble. The aqueous solution adiabatic polymerization method is most preferable because a water-absorbent resin having a small amount of components can be obtained and temperature control during polymerization is unnecessary.
　水溶液重合を行う場合、水溶液中の単量体組成物濃度は、好ましくは１０～６０重量％、より好ましくは１５～５０重量％、さらに好ましくは２０～４０重量％である。溶媒には、水と有機溶媒とを含む混合溶媒を使用することができ、有機溶媒としては、メタノール、エタノール、アセトン、メチルエチルケトン、Ｎ，Ｎ－ジメチルホルムアミド、ジメチルスルホキシド及びこれらの２種以上の混合物を挙げられる。水溶液重合を行う場合、有機溶媒の使用量（重量％）は、水の重量を基準として４０以下が好ましく、更に好ましくは３０以下である。 When carrying out aqueous solution polymerization, the concentration of the monomer composition in the aqueous solution is preferably 10 to 60% by weight, more preferably 15 to 50% by weight, and further preferably 20 to 40% by weight. As the solvent, a mixed solvent containing water and an organic solvent can be used, and as the organic solvent, methanol, ethanol, acetone, methyl ethyl ketone, N, N-dimethylformamide, dimethyl sulfoxide, and a mixture of two or more kinds of them can be used. Can be mentioned. When carrying out aqueous solution polymerization, the amount of organic solvent used (% by weight) is preferably 40 or less, and more preferably 30 or less, based on the weight of water.
　重合に開始剤を用いる場合、従来公知のラジカル重合用開始剤が使用可能であり、例えば、アゾ化合物［アゾビスイソブチロニトリル、アゾビスシアノ吉草酸及び２，２’－アゾビス（２－アミジノプロパン）ハイドロクロライド等］、無機過酸化物（過酸化水素、過硫酸アンモニウム、過硫酸カリウム及び過硫酸ナトリウム等）、有機過酸化物［過酸化ベンゾイル、ジ－ｔ－ブチルパーオキサイド、クメンヒドロパーオキサイド、コハク酸パーオキサイド及びジ（２－エトキシエチル）パーオキシジカーボネート等］及びレドックス触媒（アルカリ金属の亜硫酸塩又は重亜硫酸塩、亜硫酸アンモニウム、重亜硫酸アンモニウム及びアスコルビン酸等の還元剤とアルカリ金属の過硫酸塩、過硫酸アンモニウム、過酸化水素及び有機過酸化物等の酸化剤との組み合わせよりなるもの）等が挙げられる。これらの触媒は、単独で使用してもよく、これらの２種以上を併用しても良い。
　ラジカル重合開始剤の使用量（重量％）は、水溶性ビニルモノマー（ａ１）及び加水分解性ビニルモノマー（ａ２）の、その他のビニルモノマー（ａ３）を用いる場合は（ａ１）～（ａ３）の、合計重量に基づいて、０．０００５～５が好ましく、更に好ましくは０．００１～２である。 When an initiator is used for the polymerization, conventionally known radical polymerization initiators can be used, and examples thereof include azo compounds [azobisisobutyronitrile, azobiscyanovaleric acid and 2,2′-azobis (2-amidinopropane). Hydrochloride, etc., Inorganic peroxides (hydrogen peroxide, ammonium persulfate, potassium persulfate, sodium persulfate, etc.), Organic peroxides [benzoyl peroxide, di-t-butyl peroxide, cumene hydroperoxide, amber Acid peroxide and di (2-ethoxyethyl) peroxydicarbonate, etc.] and redox catalyst (alkali metal sulfite or bisulfite, ammonium sulfite, ammonium bisulfite, ascorbic acid and other reducing agents and alkali metal persulfate) (Combined with an oxidizing agent such as a salt, ammonium persulfate, hydrogen peroxide and an organic peroxide). These catalysts may be used alone or in combination of two or more.
The amount (% by weight) of the radical polymerization initiator is the same as that of the water-soluble vinyl monomer (a1) and the hydrolyzable vinyl monomer (a2) or (a1) to (a3) when other vinyl monomer (a3) is used. Based on the total weight, 0.0005 to 5 is preferable, and 0.001 to 2 is more preferable.
　重合方法が懸濁重合法又は逆相懸濁重合法である場合、必要に応じて、従来公知の分散剤又は界面活性剤の存在下に重合を行っても良い。また、逆相懸濁重合法の場合、従来公知のキシレン、ノルマルヘキサン及びノルマルヘプタン等の炭化水素系溶媒を使用して重合を行うことができる。 When the polymerization method is a suspension polymerization method or a reverse phase suspension polymerization method, the polymerization may be carried out in the presence of a conventionally known dispersant or surfactant, if necessary. Further, in the case of the reverse phase suspension polymerization method, the polymerization can be carried out using a conventionally known hydrocarbon solvent such as xylene, normal hexane, and normal heptane.
　重合開始温度は、使用する開始剤の種類によって適宜調整することができるが、０～１００℃が好ましく、更に好ましくは５～８０℃である。 The polymerization initiation temperature can be appropriately adjusted depending on the type of initiator used, but is preferably 0 to 100 ° C, more preferably 5 to 80 ° C.
　重合によって得られる含水ゲル重合体は、混練細断後、乾燥した後に粉砕することで架橋重合体（Ａ）を得ることができる。本発明において混練細断とは、剪断力（シア）により含水ゲルの切断と切断された含水ゲル粒子の合着を繰り返しながら含水ゲルを細かくする工程であり、本混練細断工程により微細な含水ゲル粒子が凝集した含水ゲルが得られ、吸水性樹脂粒子の表面に凹凸を形成することができる。混練細断後のゲルの大きさ（最長径）は５０μｍ～１０ｃｍが好ましく、更に好ましくは１００μｍ～２ｃｍ、特に好ましくは１ｍｍ～１ｃｍである。この範囲であると、乾燥工程での乾燥性が更に良好となる。 The hydrogel polymer obtained by the polymerization can be kneaded, shredded, dried, and then pulverized to obtain the crosslinked polymer (A). Kneading and shredding in the present invention is a step of finely cutting the hydrous gel by repeating cutting of the hydrous gel by shearing force (shear) and coalescence of the cut hydrous gel particles. A hydrogel obtained by aggregating gel particles is obtained, and irregularities can be formed on the surface of the water absorbent resin particles. The size (longest diameter) of the gel after kneading and 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, the drying property in the drying step becomes even better.
　混練粉砕後のゲル粒子の大きさ（最長径）は５０μｍ～１０ｃｍが好ましく、更に好ましくは１００μｍ～２ｃｍ、特に好ましくは１ｍｍ～１ｃｍである。この範囲であると、乾燥工程での乾燥性が更に良好となり、また添加剤である疎水性物質（ｃ）との混合性が良好となるため、結果として離水率や１．０重量％塩化カルシウム水溶液のゲル通液速度が向上する。 The size (longest diameter) of the gel particles after kneading and pulverization is preferably 50 μm to 10 cm, more preferably 100 μm to 2 cm, and particularly preferably 1 mm to 1 cm. Within this range, the drying property in the drying process is further improved, and the mixing property with the hydrophobic substance (c) as an additive is also improved, resulting in a water separation rate or 1.0% by weight calcium chloride. The gel flow rate of the aqueous solution is improved.
　混練細断は、公知の方法で行うことができ、混練細断装置（例えば、ニーダー、万能混合機、一軸又は二軸の混練押出機、ミンチ機及びミートチョッパー等）を使用して混練細断できる。脱水効率、および他物性との性能バランスの観点から４０～１２０℃、好ましくは５０～１１０℃である。混練細断回数はゲル粒子の大きさが前記範囲内であれば特に限定は無く、１回でも複数回でも良い。また、混練細断を複数回行う場合は、１つの粉砕装置で複数回行っても良いし、複数台の粉砕装置で連続的に行っても良い。 The kneading shredding can be performed by a known method, and kneading shredding using a kneading shredding device (eg, kneader, universal mixer, uniaxial or biaxial kneading extruder, mincing machine, meat chopper, etc.) it can. From the viewpoint of dehydration efficiency and performance balance with other physical properties, it is 40 to 120 ° C., preferably 50 to 110 ° C. The number of kneading and shredding is not particularly limited as long as the size of the gel particles is within the above range, and may be once or plural times. When kneading and shredding is performed a plurality of times, it may be performed a plurality of times with one crushing device or may be continuously performed with a plurality of crushing devices.
　本発明においては、重合によって得られる含水ゲル重合体は混練細断する前に細分する。本発明において細分とは、含水ゲル内部の構造を維持したまま含水ゲルを切断して細かくする工程であり、内部構造の観点から前述した混練細断とは異なる。混練細断工程前に細分することで、混練細断工程時、含水ゲルにかかる過剰な応力を緩和し、含水ゲル重合体の劣化を抑制することができるため、吸収性能が良好となり、吸水性樹脂粒子の粒子欠損度の極端な上昇を防止することが可能となる。 In the present invention, the hydrogel polymer obtained by polymerization is subdivided before kneading and chopping. In the present invention, subdivision is a step of cutting the hydrogel into fine pieces while maintaining the internal structure of the hydrogel, which is different from the kneading chopping described above from the viewpoint of the internal structure. By subdividing before the kneading shredding step, during the kneading shredding step, excessive stress applied to the hydrous gel can be relaxed, and deterioration of the hydrous gel polymer can be suppressed, resulting in good absorption performance and water absorption. It is possible to prevent an extreme increase in the degree of particle defects of the resin particles.
　細分の方法については特に限定はなく、例えばはさみで細分してもよいし、凍結した含水ゲルを粉砕装置（例えば、ハンマー式粉砕機、衝撃式粉砕機、ロール式粉砕機及びシェット気流式粉砕機）で粉砕してもよい。 The method of subdividing is not particularly limited, and may be subdivided by, for example, scissors, and a frozen water-containing gel is pulverized (for example, a hammer pulverizer, an impact pulverizer, a roll pulverizer and a shet airflow pulverizer). ).
　細分後のゲルの大きさ（最長径）は５０μｍ～１０ｃｍが好ましく、更に好ましくは１００μｍ～２ｃｍ、特に好ましくは５００μｍ～１ｃｍである。この範囲であると、その後の混練細断工程を円滑に行うことができ、吸水性樹脂粒子の吸収性能が良好になる場合がある。 The size (longest diameter) of the gel after subdivision is preferably 50 μm to 10 cm, more preferably 100 μm to 2 cm, and particularly preferably 500 μm to 1 cm. Within this range, the subsequent kneading and shredding step can be carried out smoothly, and the absorbent performance of the water-absorbent resin particles may be improved.
また、前述のとおり、重合後に得られた酸基含有ポリマーの含水ゲルを混練細断工程前又は混練細断工程中に塩基を混合して中和することもできる。なお、酸基含有ポリマーを中和する場合の酸基の中和度の好ましい範囲も、前述と同様である。 Further, as described above, the hydrogel of the acid group-containing polymer obtained after the polymerization can be neutralized by mixing a base before or during the kneading shredding step. The preferable range of the degree of neutralization of the acid group when the acid group-containing polymer is neutralized is the same as described above.
　上記混練細断工程によって得られる架橋重合体（Ａ）を含有する含水ゲル粒子を乾燥した後、粉砕して、吸水性樹脂粒子が得られる。 The water-absorbent resin particles are obtained by drying and then pulverizing the hydrogel particles containing the crosslinked polymer (A) obtained in the kneading and chopping step.
　含水ゲル粒子中の溶媒（水を含む）を乾燥（留去を含む）する方法としては、８０～３００℃の温度の熱風で乾燥する方法、１００～３００℃に加熱されたドラムドライヤー等による薄膜乾燥法、減圧乾燥法、凍結乾燥法、赤外線による乾燥法、デカンテーション及び濾過等が適用できる。 As a method for drying (including distilling) the solvent (including water) in the hydrogel particles, a method of drying with hot air at a temperature of 80 to 300 ° C., a thin film formed by a drum dryer heated to 100 to 300 ° C. A drying method, a reduced pressure drying method, a freeze drying method, an infrared ray drying method, decantation, filtration and the like can be applied.
　含水ゲル粒子の溶媒に水を含む場合、乾燥後の含水率（重量％）は、架橋重合体（Ａ）の重量に基づいて、０～２０が好ましく、更に好ましくは１～１０、特に好ましくは２～９、最も好ましくは３～８である。この範囲であると、後の粉砕工程において粉砕性が良好となり、かつ吸収性能が更に良好となる。 When the solvent of the hydrous gel particles contains water, the water content (% by weight) after drying is preferably 0 to 20, more preferably 1 to 10, and particularly preferably, based on the weight of the crosslinked polymer (A). It is 2-9, most preferably 3-8. Within this range, the pulverizability will be good in the subsequent pulverization step, and the absorption performance will be even better.
　また、含水ゲル粒子の溶媒（有機溶媒及び水等）に有機溶媒を含む場合、乾燥後の有機溶媒の含有量（重量％）は、架橋重合体（Ａ）の重量に基づいて、０～１０が好ましく、更に好ましくは０～５、特に好ましくは０～３、最も好ましくは０～１である。この範囲であると、吸水性樹脂粒子の吸収性能が更に良好となる。 When the solvent of the hydrogel particles (organic solvent, water, etc.) contains an organic solvent, the content (% by weight) of the organic solvent after drying is 0 to 10 based on the weight of the crosslinked polymer (A). Is more preferable, 0 to 5 is more preferable, 0 to 3 is particularly preferable, and 0 to 1 is the most preferable. Within this range, the absorbent performance of the water absorbent resin particles will be further improved.
　なお、有機溶媒の含有量及び含水率は、赤外水分測定器［（株）ＫＥＴＴ社製ＪＥ４００等：１２０±５℃、３０分、加熱前の雰囲気湿度５０±１０％ＲＨ、ランプ仕様１００Ｖ、４０Ｗ］により加熱したときの測定試料の重量減量から求められる。 In addition, the content and water content of the organic solvent are infrared moisture meter [JE400 manufactured by KETT Co., Ltd .: 120 ± 5 ° C., 30 minutes, atmospheric humidity before heating 50 ± 10% RH, lamp specification 100V, 40 W] and the weight loss of the measurement sample when heated.
　含水ゲル粒子を乾燥した後に粉砕する方法については、特に限定はなく、公知の粉砕装置（例えば、ハンマー式粉砕機、衝撃式粉砕機、ロール式粉砕機及びシェット気流式粉砕機等）が使用できる。得られた吸水性樹脂粒子は、必要によりふるい分け等により分級して、粒度調整できる。 The method of pulverizing the hydrogel particles after drying is not particularly limited, and a known pulverizing device (for example, a hammer pulverizer, an impact pulverizer, a roll pulverizer, a shet airflow pulverizer, etc.) can be used. .. The resulting water-absorbent resin particles can be classified by sieving or the like to adjust the particle size, if necessary.
　粉砕後、必要によりふるい分け等により分級した吸水性樹脂粒子の重量平均粒子径（μｍ）は、１５０～５００が好ましく、更に好ましくは２５０～５００、最も好ましくは３５０～４５０である。この範囲であると、吸収性能や離水率や１．０重量％塩化カルシウム水溶液のゲル通液速度の向上に更に良好となる。 The weight average particle diameter (μm) of the water-absorbent resin particles that have been classified by sieving or the like after crushing is preferably 150 to 500, more preferably 250 to 500, and most preferably 350 to 450. Within this range, the absorption performance, the water separation rate, and the gel permeation rate of the 1.0 wt% calcium chloride aqueous solution are further improved.
　なお、重量平均粒子径は、ロータップ試験篩振とう機及び標準ふるい（ＪＩＳ　Ｚ８８０１－１：２００６）を用いて、ペリーズ・ケミカル・エンジニアーズ・ハンドブック第６版（マックグローヒル・ブック・カンパニー、１９８４、２１頁）に記載の方法で測定される。すなわち、ＪＩＳ標準ふるいを、上から１０００μｍ、８５０μｍ、７１０μｍ、５００μｍ、４２５μｍ、３５５μｍ、２５０μｍ、１５０μｍ、１２５μｍ、７５μｍ及び４５μｍ、並びに受け皿、の順に組み合わせる。最上段のふるいに測定粒子の約５０ｇを入れ、ロータップ試験篩振とう機で５分間振とうさせる。各ふるい及び受け皿上の測定粒子の重量を秤量し、その合計を１００重量％として各ふるい上の粒子の重量分率を求め、この値を対数確率紙［横軸がふるいの目開き（粒子径）、縦軸が重量分率］にプロットした後、各点を結ぶ線を引き、重量分率が５０重量％に対応する粒子径を求め、これを重量平均粒子径とする。 The weight average particle size is determined by using a low tap test sieve shaker and a standard sieve (JIS Z8801-1: 2006), Perry's Chemical Engineers Handbook 6th Edition (MacGlow Hill Book Company, 1984). , Page 21). That is, the JIS standard sieve is combined from the top in the order of 1000 μm, 850 μm, 710 μm, 500 μm, 425 μm, 355 μm, 250 μm, 150 μm, 125 μm, 75 μm and 45 μm, and a saucer. About 50 g of the measurement particles are put into the uppermost sieve and shaken for 5 minutes with a low tap test sieve shaker. The weight of the measured particles on each sieve and the pan is weighed, and the total is 100% by weight to obtain the weight fraction of the particles on each sieve. This value is used as a logarithmic probability paper [the horizontal axis is the sieve opening (particle size ), And the vertical axis is the weight fraction], and a line connecting the points is drawn to obtain the particle diameter corresponding to the weight fraction of 50% by weight, which is taken as the weight average particle diameter.
　また、吸水性樹脂粒子に含まれる微粒子の含有量は少ない方が吸収性能の良化につながるため、吸水性樹脂粒子の合計重量に占める１０６μｍ以下（好ましくは１５０μｍ以下）の微粒子の含有率（重量％）は３以下が好ましく、更に好ましくは１以下である。微粒子の含有量は、上記の重量平均粒子径を求める際に作成するグラフを用いて求めることができる。 Further, the smaller the content of the fine particles contained in the water-absorbent resin particles, the better the absorption performance. Therefore, the content rate of the fine particles of 106 μm or less (preferably 150 μm or less) in the total weight of the water-absorbent resin particles (weight) %) Is preferably 3 or less, more preferably 1 or less. The content of the fine particles can be determined using the graph created when determining the weight average particle size.
　吸水性樹脂粒子の形状については特に限定はなく、不定形破砕状、リン片状、パール状及び米粒状等が挙げられる。これらの内、紙おむつ用途等での繊維状物とのからみが良く、繊維状物からの脱落の心配がないという観点から、不定形破砕状が好ましい。 The shape of the water-absorbent resin particles is not particularly limited, and examples thereof include irregularly crushed particles, flaky particles, pearl particles, and rice particles. Among them, the amorphous crushed shape is preferable from the viewpoint that it has good entanglement with the fibrous material for use in disposable diapers and the like, and there is no fear of falling off from the fibrous material.
　本発明の吸水性樹脂粒子は、疎水性物質（ｃ）を含有することができる。（ｃ）としては、炭化水素基を含有する疎水性物質（ｃ１）、フッ素原子をもつ炭化水素基を含有する疎水性物質（ｃ２）及びポリシロキサン構造をもつ疎水性物質（ｃ３）等が含まれる。 The water absorbent resin particles of the present invention can contain a hydrophobic substance (c). Examples of (c) include a hydrophobic substance (c1) containing a hydrocarbon group, a hydrophobic substance (c2) containing a hydrocarbon group having a fluorine atom, and a hydrophobic substance (c3) having a polysiloxane structure. Be done.
　炭化水素基を含有する疎水性物質（ｃ１）としては、ポリオレフィン樹脂、ポリオレフィン樹脂誘導体、ポリスチレン樹脂、ポリスチレン樹脂誘導体、ワックス、長鎖脂肪酸エステル、長鎖脂肪酸及びその塩、長鎖脂肪族アルコール、長鎖脂肪族アミド及びこれらの２種以上の混合物等が含まれる。 As the hydrophobic substance (c1) containing a hydrocarbon group, polyolefin resin, polyolefin resin derivative, polystyrene resin, polystyrene resin derivative, wax, long chain fatty acid ester, long chain fatty acid and its salt, long chain aliphatic alcohol, long chain Included are chain aliphatic amides and mixtures of two or more of these.
　ポリオレフィン樹脂としては、炭素数２～４のオレフィン｛エチレン、プロピレン、イソブチレン及びイソプレン等｝を必須構成単量体（オレフィンの含有量はポリオレフィン樹脂の重量に基づいて、少なくとも５０重量％）としてなる重量平均分子量１０００～１００万の重合体｛たとえば、ポリエチレン、ポリプロピレン、ポリイソブチレン、ポリ（エチレン－イソブチレン）及びイソプレン等｝が挙げられる。 As the polyolefin resin, a weight of an olefin having 2 to 4 carbon atoms (ethylene, propylene, isobutylene, isoprene, etc.) as an essential constituent monomer (the content of the olefin is at least 50% by weight based on the weight of the polyolefin resin). Examples thereof include polymers having an average molecular weight of 1,000 to 1,000,000 (eg, polyethylene, polypropylene, polyisobutylene, poly (ethylene-isobutylene), isoprene, etc.).
　ポリオレフィン樹脂誘導体としては、ポリオレフィン樹脂にカルボキシ基（－ＣＯＯＨ）や１，３－オキソ－２－オキサプロピレン（－ＣＯＯＣＯ－）等を導入した重量平均分子量１０００～１００万の重合体｛たとえば、ポリエチレン熱減成体、ポリプロピレン熱減成体、マレイン酸変性ポリエチレン、塩素化ポリエチレン、マレイン酸変性ポリプロピレン、エチレン－アクリル酸共重合体、エチレン－無水マレイン酸共重合体、イソブチレン－無水マレイン酸共重合体、マレイン化ポリブタジエン、エチレン－酢酸ビニル共重合体及びエチレン－酢酸ビニル共重合体のマレイン化物等｝が挙げられる。 As the polyolefin resin derivative, a polymer having a weight average molecular weight of 1,000 to 1,000,000 obtained by introducing a carboxy group (—COOH), 1,3-oxo-2-oxapropylene (—COOCO—) or the like into a polyolefin resin (for example, polyethylene heat Degradation products, polypropylene thermal degradation products, maleic acid modified polyethylene, chlorinated polyethylene, maleic acid modified polypropylene, ethylene-acrylic acid copolymers, ethylene-maleic anhydride copolymers, isobutylene-maleic anhydride copolymers, maleated Polybutadiene, ethylene-vinyl acetate copolymer, and ethylene-vinyl acetate copolymer maleated product}.
　ポリスチレン樹脂としては、重量平均分子量１０００～１００万の重合体等が使用できる。 As the polystyrene resin, a polymer having a weight average molecular weight of 1,000 to 1,000,000 can be used.
　ポリスチレン樹脂誘導体としては、スチレンを必須構成単量体（スチレンの含有量は、ポリスチレン誘導体の重量に基づいて、少なくとも５０重量％）としてなる重量平均分子量１０００～１００万の重合体｛たとえば、スチレン－無水マレイン酸共重合体、スチレン－ブタジエン共重合体及びスチレン－イソブチレン共重合体等｝が挙げられる。 As the polystyrene resin derivative, a polymer having a weight average molecular weight of 1,000 to 1,000,000 (for example, styrene-containing styrene as an essential constituent monomer (the content of styrene is at least 50% by weight based on the weight of the polystyrene derivative)) And maleic anhydride copolymers, styrene-butadiene copolymers and styrene-isobutylene copolymers.
　ワックスとしては、融点５０～２００℃のワックス｛たとえば、パラフィンワックス、ミツロウ、カルナウバワックス及び牛脂等｝が挙げられる。 Examples of the wax include waxes having a melting point of 50 to 200 ° C. (for example, paraffin wax, beeswax, carnauba wax, beef tallow, etc.).
　長鎖脂肪酸エステルとしては、炭素数８～３０の脂肪酸と炭素数１～１２のアルコールとのエステル｛たとえば、ラウリン酸メチル、ラウリン酸エチル、ステアリン酸メチル、ステアリン酸エチル、オレイン酸メチル、オレイン酸エチル、グリセリンラウリン酸モノエステル、グリセリンステアリン酸モノエステル、グリセリンオレイン酸モノエステル、ペンタエリスリットラウリン酸モノエステル、ペンタエリスリットステアリン酸モノエステル、ペンタエリスリットオレイン酸モノエステル、ソルビットラウリン酸モノエステル、ソルビットステアリン酸モノエステル、ソルビットオレイン酸モノエステル、ショ糖パルミチン酸モノエステル、ショ糖パルミチン酸ジエステル、ショ糖パルミチン酸トリエステル、ショ糖ステアリン酸モノエステル、ショ糖ステアリン酸ジエステル、ショ糖ステアリン酸トリエステル及び牛脂等｝が挙げられる。 The long-chain fatty acid ester is an ester of a fatty acid having 8 to 30 carbon atoms and an alcohol having 1 to 12 carbon atoms (for example, methyl laurate, ethyl laurate, methyl stearate, ethyl stearate, methyl oleate, oleic acid). Ethyl, glycerin lauric acid monoester, glycerin stearic acid monoester, glycerin oleic acid monoester, pentaerythritol lauric acid monoester, pentaerythritol stearic acid monoester, pentaerythritol oleic acid monoester, sorbit lauric acid monoester, Sorbit stearic acid monoester, sorbit oleic acid monoester, sucrose palmitic acid monoester, sucrose palmitic acid diester, sucrose palmitic acid triester, sucrose stearic acid monoester, sucrose stearic acid diester, sucrose stearic acid triester Ester, beef tallow, etc.}.
　長鎖脂肪酸及びその塩としては、炭素数８～３０の脂肪酸｛たとえば、ラウリン酸、パルミチン酸、ステアリン酸、オレイン酸、ダイマー酸及びベヘニン酸等｝が挙げられ、その塩としては亜鉛、カルシウム、マグネシウム又はアルミニウム（以下、それぞれＺｎ、Ｃａ、Ｍｇ、Ａｌと略す）との塩｛たとえば、パルミチン酸Ｃａ、パルミチン酸Ａｌ、ステアリン酸Ｃａ、ステアリン酸Ｍｇ、ステアリン酸Ａｌ等｝が挙げられる。 Examples of long-chain fatty acids and salts thereof include fatty acids having 8 to 30 carbon atoms (for example, lauric acid, palmitic acid, stearic acid, oleic acid, dimer acid, behenic acid, etc.), and salts thereof include zinc, calcium, Examples thereof include salts with magnesium or aluminum (hereinafter abbreviated as Zn, Ca, Mg, and Al) {for example, Ca palmitate, Al palmitate, Ca stearate, Mg stearate, Al stearate, etc.).
　長鎖脂肪族アルコールとしては、炭素数８～３０の脂肪族アルコール｛たとえば、ラウリルアルコール、パルミチルアルコール、ステアリルアルコール、オレイルアルコール等｝が挙げられる。吸収性物品の耐モレ性の観点等から、パルミチルアルコール、ステアリルアルコール、オレイルアルコールが好ましく、さらに好ましくはステアリルアルコールである。 Examples of long-chain aliphatic alcohols include aliphatic alcohols having 8 to 30 carbon atoms (eg, lauryl alcohol, palmityl alcohol, stearyl alcohol, oleyl alcohol, etc.). From the viewpoint of leakage resistance of the absorbent article, palmityl alcohol, stearyl alcohol and oleyl alcohol are preferable, and stearyl alcohol is more preferable.
　長鎖脂肪族アミドとしては、炭素数８～３０の長鎖脂肪族一級アミンと炭素数１～３０の炭化水素基を有するカルボン酸とのアミド化物、アンモニア又は炭素数１～７の１級アミンと炭素数８～３０の長鎖脂肪酸とのアミド化物、炭素数８～３０の脂肪族鎖を少なくとも１つ有する長鎖脂肪族二級アミンと炭素数１～３０のカルボン酸とのアミド化物及び炭素数１～７の脂肪族炭化水素基を２個有する二級アミンと炭素数８～３０の長鎖脂肪酸とのアミド化物が挙げられる。 As the long-chain aliphatic amide, an amidation product of a long-chain aliphatic primary amine having 8 to 30 carbon atoms and a carboxylic acid having a hydrocarbon group having 1 to 30 carbon atoms, ammonia or a primary amine having 1 to 7 carbon atoms And an amidation product of a long-chain fatty acid having 8 to 30 carbon atoms, an amidation product of a long-chain aliphatic secondary amine having at least one aliphatic chain having 8 to 30 carbon atoms, and a carboxylic acid having 1 to 30 carbon atoms, and An amidated product of a secondary amine having two aliphatic hydrocarbon groups having 1 to 7 carbon atoms and a long chain fatty acid having 8 to 30 carbon atoms can be mentioned.
　炭素数８～３０の長鎖脂肪族一級アミンと炭素数１～３０の炭化水素基を有するカルボン酸とのアミド化物としては、１級アミンとカルボン酸とが１：１で反応した物と１：２で反応した物に分けられる。１：１で反応した物としては、酢酸Ｎ－オクチルアミド、酢酸Ｎ－ヘキサコシルアミド、ヘプタコサン酸Ｎ－オクチルアミド及びヘプタコサン酸Ｎ－ヘキサコシルアミド等が挙げられる。１：２で反応したものとしては、二酢酸Ｎ－オクチルアミド、二酢酸Ｎ－ヘキサコシルアミド、ジヘプタコサン酸Ｎ－オクチルアミド及びジヘプタコサン酸Ｎ－ヘキサコシルアミド等が挙げられる。なお、１級アミンとカルボン酸とが１：２で反応した物の場合、使用するカルボン酸は、同一でも異なっていてもよい。 As the amidation product of a long-chain aliphatic primary amine having 8 to 30 carbon atoms and a carboxylic acid having a hydrocarbon group having 1 to 30 carbon atoms, 1 and 1 are obtained by reacting a primary amine with a carboxylic acid at a ratio of 1: 1. : It can be divided into two reacted products. Examples of the reaction product at 1: 1 include acetic acid N-octylamide, acetic acid N-hexacosylamide, heptacosanoic acid N-octylamide, and heptacosanoic acid N-hexacosylamide. Examples of the reaction of 1: 2 include diacetic acid N-octylamide, diacetic acid N-hexacosylamide, diheptacosanoic acid N-octylamide and diheptacosanoic acid N-hexacosylamide. When the primary amine and the carboxylic acid are reacted at a ratio of 1: 2, the carboxylic acids used may be the same or different.
　アンモニアまたは炭素数１～７の１級アミンと炭素数８～３０の長鎖脂肪酸とのアミド化物としては、アンモニア又は１級アミンとカルボン酸とが１：１で反応した物と１：２で反応した物に分けられる。１：１で反応した物としては、ノナン酸アミド、ノナン酸メチルアミド、ノナン酸Ｎ－ヘプチルアミド、ヘプタコサン酸アミド、ヘプタコサン酸Ｎ－メチルアミド、ヘプタコサン酸Ｎ－ヘプチルアミド及びヘプタコサン酸Ｎ－ヘキサコシルアミド等が挙げられる。１：２で反応したものとしては、ジノナン酸アミド、ジノナン酸Ｎ－メチルアミド、ジノナン酸Ｎ－ヘプチルアミド、ジオクタデカン酸アミド、ジオクタデカン酸Ｎ－エチルアミド、ジオクタデカン酸Ｎ－ヘプチルアミド、ジヘプタコサン酸アミド、ジヘプタコサン酸Ｎ－メチルアミド、ジヘプタコサン酸Ｎ－ヘプチルアミド及びジヘプタコサン酸Ｎ－ヘキサコシルアミド等が挙げられる。なお、アンモニア又は１級アミンとカルボン酸とが１：２で反応した物としては、使用するカルボン酸は、同一でも異なっていてもよい。 The amidated product of ammonia or a primary amine having 1 to 7 carbon atoms and a long-chain fatty acid having 8 to 30 carbon atoms is 1: 2 with a reaction product of ammonia or primary amine and carboxylic acid at 1: 1. It can be divided into reacted products. The reaction products of 1: 1 are nonanoic acid amide, nonanoic acid methylamide, nonanoic acid N-heptylamide, heptacosanoic acid amide, heptacosanoic acid N-methylamide, heptacosanoic acid N-heptylamide and heptacosanoic acid N-hexacosylamide. Etc. The reaction of 1: 2 includes dinonanoic acid amide, dinonanoic acid N-methylamide, dinonanoic acid N-heptylamide, dioctadecanoic acid amide, dioctadecanoic acid N-ethylamide, dioctadecanoic acid N-heptylamide, diheptacosanoic acid amide. , Diheptacosanoic acid N-methylamide, diheptacosanoic acid N-heptylamide, diheptacosanoic acid N-hexacosylamide and the like. The carboxylic acid used may be the same or different as the reaction product of ammonia or primary amine and carboxylic acid in a ratio of 1: 2.
　炭素数８～３０の脂肪族鎖を少なくとも１つ有する長鎖脂肪族二級アミンと炭素数１～３０のカルボン酸とのアミド化物としては、酢酸Ｎ－メチルオクチルアミド、酢酸Ｎ－メチルヘキサコシルアミド、酢酸Ｎ－オクチルヘキサコシルアミド、酢酸Ｎ－ジヘキサコシルアミド、ヘプタコサン酸Ｎ－メチルオクチルアミド、ヘプタコサン酸Ｎ－メチルヘキサコシルアミド、ヘプタコサン酸Ｎ－オクチルヘキサコシルアミド及びヘプタコサン酸Ｎ－ジヘキサコシルアミド等が挙げられる。 As the amidation product of a long-chain aliphatic secondary amine having at least one aliphatic chain having 8 to 30 carbon atoms and a carboxylic acid having 1 to 30 carbon atoms, acetic acid N-methyloctylamide, acetic acid N-methylhexacosyl Lamide, acetic acid N-octylhexacosylamide, acetic acid N-dihexacosylamide, heptacosanoic acid N-methyloctylamide, heptacosanoic acid N-methylhexacosylamide, heptacosanoic acid N-octylhexacosylamide and heptacosane Examples thereof include acid N-dihexacosylamide.
　炭素数１～７の脂肪族炭化水素基を２個有する二級アミンと炭素数８～３０の長鎖脂肪酸とのアミド化物としては、ノナン酸Ｎ－ジメチルアミド、ノナン酸Ｎ－メチルヘプチルアミド、ノナン酸Ｎ－ジヘプチルアミド、ヘプタコサン酸Ｎ－ジメチルアミド、ヘプタコサン酸Ｎ－メチルヘプチルアミド及びヘプタコサン酸Ｎ－ジヘプチルアミド等が挙げられる。 As the amidation product of a secondary amine having two aliphatic hydrocarbon groups having 1 to 7 carbon atoms and a long chain fatty acid having 8 to 30 carbon atoms, nonanoic acid N-dimethylamide, nonanoic acid N-methylheptylamide, Examples thereof include nonanoic acid N-diheptylamide, heptacosanoic acid N-dimethylamide, heptacosanoic acid N-methylheptylamide and heptacosanoic acid N-diheptylamide.
　疎水性物質（ｃ１）としては、脱水効率及び吸収性物品の耐モレ性の観点から、長鎖脂肪酸エステル、長鎖脂肪酸及びその塩、長鎖脂肪族アルコール並びに長鎖脂肪族アミドが好ましく、更に好ましくはソルビットステアリン酸エステル、ショ糖ステアリン酸エステル、ステアリン酸、ステアリン酸Ｍｇ、ステアリン酸Ｃａ、ステアリン酸Ｚｎ及びステアリン酸Ａｌ、特に好ましくはショ糖ステアリン酸エステル及びステアリン酸Ｍｇである。 The hydrophobic substance (c1) is preferably a long-chain fatty acid ester, a long-chain fatty acid and its salt, a long-chain aliphatic alcohol and a long-chain aliphatic amide, from the viewpoint of dehydration efficiency and the moisture resistance of the absorbent article, and further, Preferred are sorbit stearate, sucrose stearate, stearic acid, Mg stearate, Ca stearate, Zn stearate and Al stearate, and particularly preferred are sucrose stearate and Mg stearate.
　フッ素原子をもつ炭化水素基を含有する疎水性物質（ｃ２）としては、パーフルオロアルカン、パーフルオロアルケン、パーフルオロアリール、パーフルオロアルキルエーテル、パーフルオロアルキルカルボン酸、パーフルオロアルキルアルコール及びこれらの２種以上の混合物等が含まれる。 Examples of the hydrophobic substance (c2) containing a hydrocarbon group having a fluorine atom include perfluoroalkane, perfluoroalkene, perfluoroaryl, perfluoroalkyl ether, perfluoroalkylcarboxylic acid, perfluoroalkyl alcohol and these 2 Mixtures of more than one species are included.
　ポリシロキサン構造をもつ疎水性物質（ｃ３）としては、ポリジメチルシロキサン、ポリエーテル変性ポリシロキサン｛ポリオキシエチレン変性ポリシロキサン及びポリ（オキシエチレン・オキシプロピレン）変性ポリシロキサン等｝、カルボキシ変性ポリシロキサン、エポキシ変性ポリシロキサン、アミノ変性ポリシロキサン、アルコキシ変性ポリシロキサン等及びこれらの混合物等が含まれる。 As the hydrophobic substance (c3) having a polysiloxane structure, polydimethylsiloxane, polyether-modified polysiloxane {polyoxyethylene-modified polysiloxane and poly (oxyethylene / oxypropylene) -modified polysiloxane, etc.}, carboxy-modified polysiloxane, Epoxy-modified polysiloxane, amino-modified polysiloxane, alkoxy-modified polysiloxane and the like, and mixtures thereof are included.
　カルボキシ変性ポリシロキサンとしては、例えば、Ｘ－２２－３７０１Ｅ、Ｘ－２２－３７１０（いずれも信越化学工業社製）、ＤＯＷＳＩＬ（型番　ＢＹ１６－８８０Ｆｌｕｉｄ）、ＤＯＷＳＩＬ（型番ＢＹ１６－８８０）（ダウ・東レ株式会社製）などが挙げられる。カルボキシル基のポリシロキサン主鎖に対する位置は、側鎖及び／または末端である。 Examples of the carboxy-modified polysiloxane include X-22-3701E, X-22-3710 (all manufactured by Shin-Etsu Chemical Co., Ltd.), DOWSIL (model number BY16-880Fluid), and DOWNSIL (model number BY16-880) (Dow-Toray shares). Company made) etc. The position of the carboxyl group with respect to the polysiloxane main chain is a side chain and / or a terminal.
　エポキシ変性ポリシロキサンとしては、例えば、Ｘ－２２－３４３（信越化学工業社製）、ＫＦ－１０１、ＫＦ－１００１、Ｘ－２２－２０００、Ｘ－２２－２０４６、ＫＦ－１０２、Ｘ－２２－４７４１、ＫＦ－１００２、ＫＦ－１００５（いずれも信越化学工業社製）、ＤＯＷＳＩＬ（型番ＢＹ　１６－８３９Ｆｌｕｉｄ）、ＤＯＷＳＩＬ（型番　ＢＹ８４１１Ｆｌｕｉｄ）、ＤＯＷＳＩＬ（型番ＢＹ　８４１３Ｆｌｕｉｄ）、ＤＯＷＳＩＬ（型番　ＢＹ８４２１Ｆｌｕｉｄ）（いずれもダウ・東レ株式会社製）、ＳＦ８４１１、ＳＦ８４１３，ＢＹ１６－８３９、ＢＹ１６－８７６、ＦＺ－３７３６、ＳＦ８４２１（いずれも東レ・ダウコーニング社製）などが挙げられる。エポキシ基のポリシロキサン主鎖に対する位置は、側鎖及び／または末端である。 Examples of the epoxy-modified polysiloxane include X-22-343 (manufactured by Shin-Etsu Chemical Co., Ltd.), KF-101, KF-1001, X-22-2000, X-22-2046, KF-102, X-22-. 4741, KF-1002, KF-1005 (all manufactured by Shin-Etsu Chemical Co., Ltd.), DOWSIL (model number BY 16-839 Fluid), DOWNSIL (model number BY8411Fluid), DOWSIL (model number BY8413Fluid), DOWNSIL (model number BY8421Fluid) (all are Dow) -Toray Industries, Inc.), SF8411, SF8413, BY16-839, BY16-876, FZ-3736, SF8421 (all manufactured by Toray Dow Corning). The position of the epoxy group with respect to the polysiloxane main chain is a side chain and / or a terminal.
　アミノ変性ポリシロキサンとしては、変性基が１級アミンのモノアミン変性タイプと、２級アミンのジアミン変性タイプのものが挙げられる。
　モノアミノ変性タイプとしては、例えば、ＫＦ－８６８、ＫＦ－８６５、ＫＦ－８６４、ＰＡＭ－Ｅ、ＫＦ－８０１０、Ｘ－２２－１６１Ａ、Ｘ－２２－１６１Ｂ、ＫＦ－８０１２、ＫＦ－８００８、Ｘ－２２－１６６０Ｂ－３、Ｘ－２２－９４０９（いずれも信越化学工業社製）、ＤＯＷＳＩＬ（型番　ＢＹ１６－２０５）、ＤＯＷＳＩＬ（型番　ＢＹ１６－２１３）、ＤＯＷＳＩＬ（型番　ＢＹ１６－８４９Ｆｌｕｉｄ）、ＤＯＷＳＩＬ（型番　ＢＹ１６－８５３Ｕ）、ＤＯＷＳＩＬ（型番　ＢＹ１６－８７１）、ＤＯＷＳＩＬ（型番　ＢＹ１６－８７２）、ＤＯＷＳＩＬ（型番　ＢＹ１６－８７９Ｂ）、ＤＯＷＳＩＬ（型番　ＢＹ１６－８９２）、ＤＯＷＳＩＬ（型番　ＦＺ－３７０５）、ＤＯＷＳＩＬ（型番　ＦＺ－３７１０Ｆｌｕｉｄ）、ＤＯＷＳＩＬ（型番　ＦＺ－３７６０）、ＤＯＷＳＩＬ（型番　ＦＺ－３７８５）、ＤＯＷＳＩＬ（型番　ＳＦ８４１７Ｆｌｕｉｄ）（いずれも東レ・ダウ株式会社製）などが挙げられる。ジアミノ変性タイプとしては、例えば、ＫＦ－８５９、ＫＦ－３９３、ＫＦ－８６０、ＫＦ－８６０、ＫＦ－８００４、ＫＦ－８００２、ＫＦ－８００５、ＫＦ－８６７、ＫＦ－８０２１、ＫＦ－８６９、ＫＦ－８６１（いずれも信越化学工業社製）などが挙げられる。ジアミノ基のポリシロキサン主鎖に対する位置は、側鎖及び／または末端である。 Examples of the amino-modified polysiloxane include a monoamine-modified type having a primary amine as a modifying group and a diamine-modified type having a secondary amine.
Examples of the monoamino-modified type include KF-868, KF-865, KF-864, PAM-E, KF-8010, X-22-161A, X-22-161B, KF-8012, KF-8008, X- 22-1660B-3, X-22-9409 (all manufactured by Shin-Etsu Chemical Co., Ltd.), DOWSIL (model number BY16-205), DOWSIL (model number BY16-213), DOWNSIL (model number BY16-849Fluid), DOWNSIL (model BY16-). 853U), DOWSIL (model number BY16-871), DOWSIL (model number BY16-872), DOWSIL (model number BY16-879B), DOWNSIL (model number BY16-892), DOWNSIL (model number FZ-3705), DOWNSIL (model number FZ-3710Fluid). , DOWSIL (model number FZ-3760), DOWSIL (model number FZ-3785), DOWSIL (model number SF8417Fluid) (all manufactured by Toray Dow Co., Ltd.) and the like. Examples of the diamino-modified type include KF-859, KF-393, KF-860, KF-860, KF-8004, KF-8002, KF-8005, KF-867, KF-8021, KF-869, KF-. 861 (both manufactured by Shin-Etsu Chemical Co., Ltd.) and the like. The position of the diamino group with respect to the polysiloxane main chain is a side chain and / or a terminal.
　アルコキシ変性ポリシロキサンとしては、例えば、Ｘ－２２－４９５２、Ｘ－２２－４２７２、ＫＦ－６１２３、ＫＦ－３５１Ａ、ＫＦ－３５２Ａ、ＫＦ－３５３、ＫＦ－３５４Ｌ、ＫＦ－３５５Ａ、ＫＦ－６１５Ａ、ＫＦ－９４５、ＫＦ－６４０、ＫＦ－６４２、ＫＦ－６４３、ＫＦ－６４４、ＫＦ－６０２０、ＫＦ－６２０４、Ｘ－２２－４５１５、ＫＦ－６０１１，ＫＦ－６０１２、ＫＦ－６０１５、ＫＦ－６０１７、ＤＯＷＳＩＬ（型番　５０１Ｗ　Ａｄｄｉｔｉｖｅ）、ＤＯＷＳＩＬ（型番　ＦＺ－２１１０）、ＤＯＷＳＩＬ（型番　ＦＺ－２１２３）、ＤＯＷＳＩＬ（型番　Ｌ－７００１）、ＤＯＷＳＩＬ（型番　ＳＦ８４１０Ｆｌｕｉｄ）、ＤＯＷＳＩＬ（型番　ＳＨ３７４６Ｆｌｕｉｄ）、ＤＯＷＳＩＬ（型番　ＳＨ８４００Ｆｌｕｉｄ）、ＤＯＷＳＩＬ（型番　ＳＨ８７００Ｆｌｕｉｄ）（いずれも東レ・ダウ株式会社製）などが挙げられる。アルコキシ基のポリシロキサン主鎖に対する位置は、側鎖及び／または末端である。 Examples of the alkoxy-modified polysiloxane include X-22-4952, X-22-4272, KF-6123, KF-351A, KF-352A, KF-353, KF-354L, KF-355A, KF-615A and KF. -945, KF-640, KF-642, KF-643, KF-644, KF-6020, KF-6204, X-22-4515, KF-6011, KF-6012, KF-6015, KF-6017, DOWNSIL (Model number 501W Additive), OWSIL (model number FZ-2110), OWSIL (model number FZ-2123), DOWNSIL (model number L-7001), DOWNSIL (model number SF8410Fluid), DOWNSIL (model number SH3746Fluid), OWSIL (model number SHIDOSHID, SH8400IL). The model number is SH8700 Fluid (both manufactured by Toray Dow Co., Ltd.). The position of the alkoxy group with respect to the polysiloxane main chain is a side chain and / or a terminal.
　疎水性物質（ｃ３）としては、脱水効率及び吸収性物品の耐モレ性の観点から、カルボキシ変性ポリシロキサン、エポキシ変性ポリシロキサン、アミノ変性ポリシロキサン、アルコキシ変性ポリシロキサンが好ましく、更に好ましくはカルボキシ変性ポリシロキサンである。 The hydrophobic substance (c3) is preferably a carboxy-modified polysiloxane, an epoxy-modified polysiloxane, an amino-modified polysiloxane, or an alkoxy-modified polysiloxane, and more preferably carboxy-modified, from the viewpoints of the dehydration efficiency and the moisture resistance of the absorbent article. It is a polysiloxane.
　疎水性物質（ｃ）のＨＬＢ値は、１～１０が好ましく、さらに好ましくは１～８、特に好ましくは１～７である。この範囲であると、吸収性物品の耐モレ性がさらに良好となる。なお、ＨＬＢ値は、親水性－疎水性バランス（ＨＬＢ）値を意味し、小田法（界面活性剤入門、２１２頁、藤本武彦、三洋化成工業株式会社発行、２００７年発行）により求められる。 The HLB value of the hydrophobic substance (c) is preferably 1-10, more preferably 1-8, and particularly preferably 1-7. Within this range, the absorbent article has further improved resistance to leakage. The HLB value means a hydrophilic-hydrophobic balance (HLB) value, and is determined by the Oda method (Surfactant Primer, page 212, Takehiko Fujimoto, Sanyo Chemical Industry Co., Ltd., 2007).
　疎水性物質（ｃ）のうち、脱水効率及び吸収性物品の耐モレ性の観点から、炭化水素基を含有する疎水性物質（ｃ１）、またはポリシロキサン構造をもつ疎水性物質（ｃ３）が好ましい。更に好ましくは、疎水性物質（ｃ３）である。 Among the hydrophobic substances (c), the hydrophobic substance (c1) containing a hydrocarbon group or the hydrophobic substance (c3) having a polysiloxane structure is preferable from the viewpoints of dehydration efficiency and leakage resistance of the absorbent article. .. More preferably, it is the hydrophobic substance (c3).
　疎水性物質（ｃ）の含有量（重量％）は、吸水特性（特に、吸水速度と通液速度）の観点から、架橋重合体（Ａ）の重量に基づいて、０．００１～２．０重量％であり、好ましくは０．０１～１．０重量％、特に好ましくは０．０２～０．３重量％である。 The content (% by weight) of the hydrophobic substance (c) is 0.001 to 2.0 based on the weight of the crosslinked polymer (A) from the viewpoint of water absorption characteristics (particularly, water absorption rate and liquid passing rate). %, Preferably 0.01 to 1.0% by weight, particularly preferably 0.02 to 0.3% by weight.
　疎水性物質（ｃ）は、吸水性樹脂粒子の何れの箇所に存在していてもよいが、吸水特性（特に、吸水速度）及び離水率の観点から、吸水性樹脂粒子の内部に存在することが好ましい。 The hydrophobic substance (c) may be present at any position of the water absorbent resin particles, but it should be present inside the water absorbent resin particles from the viewpoint of water absorption characteristics (particularly, water absorption rate) and water separation rate. Is preferred.
　疎水性物質（ｃ）は、前述した混練細断工程時において、架橋重合体（Ａ）を含有する含水ゲルが（ｃ）を含有していればよく、重合工程又は混練細断工程において（ｃ）を含有することが好ましい。（ｃ）を添加する方法としては、重合工程開始後であって重合工程完了前において重合液に添加する方法、重合工程完了後の混練細断工程前において含水ゲルに添加する方法、混練細断工程中の含水ゲル粒子に添加する方法が挙げられるが、離水率向上の観点から、重合工程完了後の混練細断工程前において含水ゲルに添加する方法、又は混練細断工程中の含水ゲル粒子に添加する方法が好ましく、さらに好ましくは混練細断工程中の含水ゲル粒子に添加する方法である。なお、疎水性物質（ｃ）は、水及び／又は有機溶媒に、溶解及び／又は分散した形態でも添加できる。 The hydrophobic substance (c) need only be such that the hydrogel containing the crosslinked polymer (A) contains (c) during the above-mentioned kneading and shredding step. ) Is preferably contained. As a method of adding (c), a method of adding to the polymerization liquid after the start of the polymerization step and before the completion of the polymerization step, a method of adding to the hydrogel before the kneading shredding step after the completion of the polymerization step, and a kneading shredding Examples include a method of adding to the hydrogel particles during the step, from the viewpoint of improving the water separation rate, a method of adding to the hydrogel before the kneading shredding step after the completion of the polymerization step, or the hydrogel particles during the kneading shredding step. To the hydrogel particles during the kneading and shredding step. The hydrophobic substance (c) can be added to water and / or an organic solvent in a dissolved and / or dispersed form.
　吸水性樹脂粒子は、さらに粒子表面が表面架橋されていることが好ましい。従って、本発明の製造方法は、前述の含水ゲル粒子を乾燥し、粉砕した後、表面架橋する工程を含んでも良い。表面架橋することにより更にゲル強度を向上させることができ、実使用において望ましい保水量と荷重下における吸収量とを満足させることができる。なお、含水ゲル粒子に対して表面架橋を行う工程を単に架橋工程ともいう。 It is preferable that the surface of the water-absorbent resin particles is further surface-crosslinked. Therefore, the production method of the present invention may include a step of drying and pulverizing the above-mentioned hydrogel particles and then surface-crosslinking them. By surface-crosslinking, the gel strength can be further improved, and the desired water retention amount and absorption amount under load can be satisfied in actual use. The step of surface-crosslinking the hydrogel particles is also simply referred to as a crosslinking step.
　吸水性樹脂粒子を表面架橋する方法としては、従来公知の方法、例えば、吸水性樹脂を粒子状とした後、表面架橋剤（ｅ）、水及び溶媒の混合溶液を混合し、加熱反応する方法が挙げられる。混合する方法としては、吸水性樹脂粒子に上記混合溶液を噴霧するか、上記混合溶液に吸水性樹脂粒子をディッピングする方法等が挙げられ、好ましくは、吸水性樹脂粒子に上記混合溶液を噴霧して混合する方法である。 As a method for surface-crosslinking the water-absorbent resin particles, a conventionally known method, for example, a method in which the water-absorbent resin is made into particles, a surface-crosslinking agent (e), water and a mixed solution of a solvent are mixed and the mixture is heated and reacted. Is mentioned. Examples of the mixing method include spraying the mixed solution onto the water-absorbent resin particles, or a method of dipping the water-absorbent resin particles into the mixed solution, and preferably spraying the mixed solution onto the water-absorbent resin particles. It is a method of mixing.
　表面架橋剤（ｅ）としては、例えば、エチレングリコールジグリシジルエーテル、グリセロールジグリシジルエーテル及びポリグリセロールポリグリシジルエーテル等のポリグリシジル化合物、グリセリン及びエチレングリコール等の多価アルコール、エチレンカーボネート、ポリアミン並びに多価金属化合物等が挙げられる。これらの内、比較的低い温度で架橋反応を行うことができる点で好ましいのは、ポリグリシジル化合物である。これらの表面架橋剤は単独で使用してもよく、２種以上を併用してもよい。 Examples of the surface cross-linking agent (e) include polyglycidyl compounds such as ethylene glycol diglycidyl ether, glycerol diglycidyl ether and polyglycerol polyglycidyl ether, polyhydric alcohols such as glycerin and ethylene glycol, ethylene carbonate, polyamines and polyhydric alcohols. A metal compound etc. are mentioned. Of these, polyglycidyl compounds are preferable because they can be crosslinked at a relatively low temperature. These surface cross-linking agents may be used alone or in combination of two or more.
　表面架橋剤（ｅ）の使用量は、架橋前の吸水性樹脂粒子の重量に基づいて、好ましくは０．００１～５重量％、更に好ましくは０．００５～２重量％である。表面架橋剤（ｅ）の使用量が０．００１重量％未満の場合は、表面架橋度が不足し、荷重下における吸収量の向上効果が不充分となる場合がある。一方、表面架橋剤（ｅ）の使用量が５重量％を超える場合は、表面の架橋度が過度となりすぎて保水量が低下する場合がある。 The amount of the surface-crosslinking agent (e) used is preferably 0.001 to 5% by weight, more preferably 0.005 to 2% by weight, based on the weight of the water-absorbent resin particles before crosslinking. When the amount of the surface cross-linking agent (e) used is less than 0.001% by weight, the degree of surface cross-linking may be insufficient and the effect of improving the absorption amount under load may be insufficient. On the other hand, when the amount of the surface cross-linking agent (e) used exceeds 5% by weight, the degree of cross-linking on the surface becomes excessive and the water retention amount may decrease.
　表面架橋時の水の使用量は、架橋前の吸水性樹脂粒子の重量に基づいて、好ましくは０．５～１０重量％、更に好ましくは１～７重量％である。水の使用量が０．５重量％未満の場合、表面架橋剤（ｅ）の吸水性樹脂粒子内部への浸透度が不充分となり、荷重下における吸収量の向上効果が乏しくなる場合がある。一方、水の使用量が１０重量％を越えると、表面架橋剤（ｅ）の内部への浸透が過度となり、荷重下における吸収量の向上は認められるものの、保水量が低下する場合がある。 The amount of water used for surface crosslinking is preferably 0.5 to 10% by weight, more preferably 1 to 7% by weight, based on the weight of the water-absorbent resin particles before crosslinking. When the amount of water used is less than 0.5% by weight, the degree of penetration of the surface cross-linking agent (e) into the water-absorbent resin particles becomes insufficient, and the effect of improving the amount absorbed under load may be poor. On the other hand, when the amount of water used exceeds 10% by weight, the penetration of the surface cross-linking agent (e) into the interior becomes excessive, and although the absorption amount under load is improved, the water retention amount may decrease.
　表面架橋時に水と併用して使用される溶媒としては従来公知のものが使用可能であり、表面架橋剤（ｅ）の吸水性樹脂粒子内部への浸透度合い、表面架橋剤（ｅ）の反応性等を考慮し、適宜選択して使用することができるが、好ましくは、メタノール、ジエチレングリコール、プロピレングリコール等の水に溶解しうる親水性有機溶媒である。溶媒は単独で使用してもよいし、２種以上を併用してもよい。 As the solvent used in combination with water at the time of surface cross-linking, conventionally known ones can be used, the penetration degree of the surface cross-linking agent (e) into the water-absorbent resin particles, the reactivity of the surface cross-linking agent (e). Although it can be appropriately selected and used in consideration of the above, a hydrophilic organic solvent such as methanol, diethylene glycol or propylene glycol, which is soluble in water, is preferable. The solvent may be used alone or in combination of two or more kinds.
　溶媒の使用量は、溶媒の種類により適宜調整できるが、表面架橋前の吸水性樹脂粒子の重量に基づいて、好ましくは１～１０重量％である。また、水に対する溶媒の比率についても任意に調整することができるが、好ましくは重量基準で２０～８０重量％、更に好ましくは３０～７０重量％である。 The amount of the solvent used can be appropriately adjusted depending on the type of the solvent, but it is preferably 1 to 10% by weight based on the weight of the water-absorbent resin particles before surface crosslinking. The ratio of the solvent to water can be adjusted arbitrarily, but it is preferably 20 to 80% by weight, more preferably 30 to 70% by weight.
　表面架橋を行うには、表面架橋剤（ｅ）と水と溶媒との混合溶液を従来公知の方法で吸水性樹脂粒子と混合し、加熱反応を行う。反応温度は、好ましくは１００～２３０℃、更に好ましくは１２０～１８０℃である。反応時間は、反応温度により適宜調整することができるが、好ましくは３～６０分、更に好ましくは１０～４５分である。表面架橋して得られる吸水性樹脂粒子を、最初に用いた表面架橋剤と同種又は異種の表面架橋剤を用いて、更に表面架橋することも可能である。 To carry out surface cross-linking, a mixed solution of the surface cross-linking agent (e), water and a solvent is mixed with the water-absorbent resin particles by a conventionally known method, and a heating reaction is carried out. The reaction temperature is preferably 100 to 230 ° C, more preferably 120 to 180 ° C. The reaction time can be appropriately adjusted depending on the reaction temperature, but is preferably 3 to 60 minutes, more preferably 10 to 45 minutes. The water-absorbent resin particles obtained by surface-crosslinking can be further surface-crosslinked by using the same or different surface-crosslinking agent as the surface-crosslinking agent initially used.
　表面架橋の後、必要により篩別して粒度調整してもよい。粒度調整後に得られた粒子の重量平均粒子径、微粒子の含有量の好ましい範囲は、前述と同様である。また、含水ゲル粒子に対して表面架橋を行った後の粒度調節工程を架橋工程後の後工程、あるいは単に後工程ともいう。 After surface cross-linking, if necessary, it may be sieved to adjust the particle size. The preferable ranges of the weight average particle diameter of the particles obtained after the particle size adjustment and the content of the fine particles are the same as described above. The particle size adjusting step after surface-crosslinking the hydrogel particles is also referred to as a post-step after the cross-linking step, or simply as a post-step.
　架橋工程及び／又は架橋工程後の後工程で、疎水性物質（ｃ）を水及び／又は有機溶媒に、溶解及び／又は分散した形態でも添加できる。架橋工程及び／又は架橋工程後の後工程で添加することで、粒子表面に均一的に添加することができるため脱水効率を向上させることができる。 The hydrophobic substance (c) can be added to water and / or an organic solvent in a dissolved and / or dispersed form in the crosslinking step and / or the post-step after the crosslinking step. By adding in the cross-linking step and / or in the post-step after the cross-linking step, the particles can be uniformly added to the surface of the particles, so that the dehydration efficiency can be improved.
　本発明の吸水性樹脂粒子は、更に多価金属塩（ｆ）を含有してもよく、このために、本発明の製造方法は、更に多価金属塩（ｆ）と混合する工程を含んでも良い。多価金属塩（ｆ）を含有することで、吸水性樹脂粒子の耐ブロッキング性及び通液性が向上する。多価金属塩（ｆ）としては、マグネシウム、カルシウム、ジルコニウム、アルミニウム及びチタニウムからなる群から選ばれる少なくとも１種の金属と前記の無機酸又は有機酸との塩が挙げられる。 The water-absorbent resin particles of the present invention may further contain a polyvalent metal salt (f), and therefore the production method of the present invention may further include a step of mixing with the polyvalent metal salt (f). good. By containing the polyvalent metal salt (f), blocking resistance and liquid permeability of the water absorbent resin particles are improved. Examples of the polyvalent metal salt (f) include salts of at least one metal selected from the group consisting of magnesium, calcium, zirconium, aluminum and titanium and the above-mentioned inorganic acid or organic acid.
　多価金属塩（ｆ）としては、入手の容易性や溶解性の観点から、アルミニウムの無機酸塩及びチタニウムの無機酸塩が好ましく、更に好ましいのは硫酸アルミニウム、塩化アルミニウム、硫酸カリウムアルミニウム及び硫酸ナトリウムアルミニウム、特に好ましいのは硫酸アルミニウム及び硫酸ナトリウムアルミニウム、最も好ましいのは硫酸ナトリウムアルミニウムである。これらは１種を単独で用いても良いし、２種以上を併用しても良い。 As the polyvalent metal salt (f), an inorganic acid salt of aluminum and an inorganic acid salt of titanium are preferable from the viewpoint of easy availability and solubility, and more preferable are aluminum sulfate, aluminum chloride, potassium aluminum sulfate and sulfuric acid. Sodium aluminum, particularly preferred are aluminum sulfate and sodium aluminum sulfate, and most preferred is sodium aluminum sulfate. These may be used alone or in combination of two or more.
　多価金属塩（ｆ）の使用量（重量％）は、吸収性能及び耐ブロッキング性の観点から架橋重合体（Ａ）の重量に基づいて、０．０１～５が好ましく、更に好ましくは０．０５～４、特に好ましくは０．１～３である。 The amount (% by weight) of the polyvalent metal salt (f) used is preferably 0.01 to 5, more preferably 0. 5, based on the weight of the crosslinked polymer (A) from the viewpoint of absorption performance and blocking resistance. 05 to 4, particularly preferably 0.1 to 3.
　多価金属塩（ｆ）と混合するタイミングとしては特に制限はないが、前記の含水ゲルを乾燥して吸水性樹脂粒子を得た以降に混合することが吸収性能及び耐ブロッキング性の観点から好ましい。 The timing of mixing with the polyvalent metal salt (f) is not particularly limited, but it is preferable to mix it after the water-containing gel is dried to obtain water-absorbent resin particles, from the viewpoint of absorption performance and blocking resistance. ..
　本発明の吸水性樹脂粒子はさらに表面に無機質粉末をコーティングすることもできる。無機質粉末としては、親水性無機物粒子及び疎水性無機粒子等が含まれる。親水性無機物粒子としては、ガラス、シリカゲル、シリカ及びクレー等の粒子が挙げられる。疎水性無機物粒子としては、炭素繊維、カオリン、タルク、マイカ、ベントナイト、セリサイト、アスベスト及びシラス等の粒子が挙げられる。これらのうち、親水性無機粒子が好ましく、最も好ましいのはシリカである。 The surface of the water-absorbent resin particles of the present invention can be further coated with an inorganic powder. Examples of the inorganic powder include hydrophilic inorganic particles and hydrophobic inorganic particles. Examples of the hydrophilic inorganic particles include particles of glass, silica gel, silica, clay and the like. Examples of the hydrophobic inorganic particles include particles of carbon fiber, kaolin, talc, mica, bentonite, sericite, asbestos and shirasu. Of these, hydrophilic inorganic particles are preferable, and silica is the most preferable.
　親水性無機粒子及び疎水性無機粒子の形状としては、不定形（破砕状）、真球状、フィルム状、棒状及び繊維状等のいずれでもよいが、不定形（破砕状）又は真球状が好ましく、さらに好ましくは真球状である。 The shape of the hydrophilic inorganic particles and the hydrophobic inorganic particles may be any of amorphous (crushed), spherical, film-shaped, rod-shaped and fibrous, etc., but the amorphous (crushed) or spherical is preferable, The spherical shape is more preferable.
　無機質粉末の含有量（重量％）は、吸水性樹脂粒子の重量に基づいて、０．０１～３．０が好ましく、さらに好ましくは０．０５～１.０、次に好ましくは０．１～０．８、特に好ましくは０．２～０．７、最も好ましくは０．３～０．６である。この範囲であると、吸収性物品のゲル通液速度がさらに良好となる。 The content (% by weight) of the inorganic powder is preferably 0.01 to 3.0, more preferably 0.05 to 1.0, and most preferably 0.1 to 3.0 based on the weight of the water absorbent resin particles. 0.8, particularly preferably 0.2 to 0.7, most preferably 0.3 to 0.6. Within this range, the gel permeation rate of the absorbent article will be further improved.
　本発明の吸水性樹脂粒子には、他の添加剤｛たとえば、公知（特開２００３－２２５５６５号、特開２００６－１３１７６７号等）の防腐剤、防かび剤、抗菌剤、酸化防止剤、紫外線吸収剤、着色剤、芳香剤、消臭剤及び有機質繊維状物等｝を含むこともできる。これらの添加剤を含有させる場合、添加剤の含有量（重量％）は、吸水性樹脂粒子の重量に基づいて、０．００１～１０が好ましく、さらに好ましくは０．０１～５、特に好ましくは０．０５～１、最も好ましくは０．１～０．５である。 The water-absorbent resin particles of the present invention may contain other additives (for example, known antiseptics, antifungal agents, antibacterial agents, antioxidants, ultraviolet rays, etc. (Japanese Patent Laid-Open Nos. 2003-225565 and 2006-131767). Absorbents, colorants, fragrances, deodorants, organic fibrous substances, etc.} can also be included. When these additives are contained, the content (% by weight) of the additive is preferably 0.001 to 10, more preferably 0.01 to 5, and particularly preferably, based on the weight of the water absorbent resin particles. It is 0.05 to 1, most preferably 0.1 to 0.5.
　本発明の吸水性樹脂粒子の見かけ密度（ｇ／ｍｌ）は、０．４０～０．６２が好ましく、更に好ましくは０．４５～０．６０、特に好ましくは０．４８～０．５８である。この範囲であると、離水率とゲル通液速度が更に良好となる。吸水性樹脂粒子の見かけ密度は、ＪＩＳ　Ｋ７３６５：１９９９に準拠して、２５℃で測定される。 The apparent density (g / ml) of the water absorbent resin particles of the present invention is preferably 0.40 to 0.62, more preferably 0.45 to 0.60, and particularly preferably 0.48 to 0.58. .. Within this range, the water separation rate and the gel flow rate are further improved. The apparent density of the water-absorbent resin particles is measured at 25 ° C according to JIS K7365: 1999.
　本発明の吸水性樹脂粒子の生理食塩水に対する保水量（ｇ／ｇ）は３０～５０であることが好ましく、より好ましくは３３～４９であり、３６～４８が更に好ましく、３９～４７が特に好ましい。３０未満であると、繰り返し使用時に漏れが生じやすく好ましくない。また、５０を超えるとブロッキングしやすくなるため好ましくない。保水量は、架橋剤（ｂ）および表面架橋剤（ｅ）の種類と量で適宜調整することができる。従って、例えば、保水量を上げる必要がある場合、架橋剤（ｂ）および表面架橋剤（ｅ）の使用量を低下させることで容易に実現することができる。 The water retention capacity (g / g) of the water-absorbent resin particles of the present invention with respect to physiological saline is preferably 30 to 50, more preferably 33 to 49, further preferably 36 to 48, and particularly 39 to 47. preferable. When it is less than 30, leakage tends to occur during repeated use, which is not preferable. Further, when it exceeds 50, blocking tends to occur, which is not preferable. The water retention amount can be appropriately adjusted by the types and amounts of the crosslinking agent (b) and the surface crosslinking agent (e). Therefore, for example, when it is necessary to increase the water retention amount, it can be easily realized by reducing the amounts of the crosslinking agent (b) and the surface crosslinking agent (e) used.
　本発明の吸水性樹脂粒子の生理食塩水のゲル通液速度（ｍｌ／分）は５～２５０であることが好ましく、さらに好ましくは１０～２３０、特に好ましくは３０～２１０である。生理食塩水のゲル通液速度（ｍｌ／分）が５未満であると液の拡散性が低下し、その結果、漏れやかぶれに繋がる懸念あり、２５０を超えると液の拡散性が大き過ぎるため、吸水性樹脂粒子に吸水される前に吸収体から漏れてしまう懸念がある。 The gel permeation rate (ml / min) of the physiological saline of the water-absorbent resin particles of the present invention is preferably 5 to 250, more preferably 10 to 230, and particularly preferably 30 to 210. If the gel flow rate (ml / min) of physiological saline is less than 5, the diffusivity of the liquid may decrease, and as a result, leakage or rash may occur. If it exceeds 250, the diffusivity of the liquid may be too large. However, there is a concern that the water-absorbent resin particles may leak from the absorbent before being absorbed by the water-absorbent resin particles.
　本発明における離水率は、下記式（１）で示される値であり、生理食塩水に対する保水量と、保水量測定後の膨潤ゲルを１．０重量％塩化カルシウム水溶液で処理した後の保水量との比率から算出される。即ち、脱水剤処理前の膨潤ゲルの重量に対する処理後の分離された水の重量比率を示す。従って、離水率が高いほど、所定の脱水剤処理による脱水効率が優れていることを意味する。
　離水率［％］＝｛１－（１．０重量％塩化カルシウム水溶液処理後の保水量［ｇ／ｇ］）／（生理食塩水に対する保水量［ｇ／ｇ］）｝×１００　　　（１）
なお、具体的な測定方法については後述する。 The water separation rate in the present invention is a value represented by the following formula (1), and a water retention amount with respect to physiological saline and a water retention amount after the swelling gel after the water retention amount measurement is treated with a 1.0 wt% calcium chloride aqueous solution. It is calculated from the ratio of That is, the weight ratio of the separated water after the treatment to the weight of the swollen gel before the treatment with the dehydrating agent is shown. Therefore, it means that the higher the water separation rate, the more excellent the dehydration efficiency by the predetermined dehydrating agent treatment.
Water separation rate [%] = {1- (water retention amount after treatment with 1.0 wt% calcium chloride aqueous solution [g / g]) / (water retention amount against physiological saline [g / g])} × 100 (1)
The specific measuring method will be described later.
　本発明の吸水性樹脂粒子の離水率（％）は脱水処理の効率性の観点から、７０以上であり、より好ましくは７３以上であり、特に好ましくは７５以上である。上限値は高いほど好ましく特に制限されないが、他物性との性能バランスや生産性の観点から、好ましくは９５以下、より好ましくは９０以下である。離水率を向上させるための手段としては、粒子の比表面積を広げることや粒子内又は粒子表面の親水性と疎水性のバランスを調整することが考えられる。達成するための手段としては、例えば、重合工程、混練細断工程、架橋工程、及び／又は架橋工程後の後工程において疎水性物質を併用することや、含水ゲルを混練する工程におけるゲル温度を調整すること、含水ゲルから脱水する際の乾燥時の加熱温度を上げること、架橋工程での加熱温度を上げること、重量平均粒子径を下げることなどが挙げられる。含水ゲルを混練する工程におけるゲル温度は、脱水効率、および他物性との性能バランスから好ましくは４０～１２０℃、より好ましくは５０～１１０℃である。含水ゲルから脱水する際の乾燥時の加熱温度としては、他物性との性能バランスや生産性の観点から、好ましくは１００～３００℃、より好ましくは１１０～２８０℃である。３００℃を超えて加熱した場合、吸水性樹脂粒子が熱劣化を受けるため好ましくない。架橋工程での加熱温度としては、好ましくは１００～２３０℃、より好ましくは１２０～１８０℃である。この範囲であると、疎水性物質が融解、又は粘度が低下することで吸収性樹脂粒子表面を被覆するためゲル同士の合着を防止し、脱水剤との反応点を増やすことができると考えられる。重量平均粒子径は、脱水性と他物性の性能バランスの観点から、１５０μｍから５００μｍが好ましく、より好ましくは２００μｍから４００μｍである。 From the viewpoint of the efficiency of dehydration treatment, the water separation ratio (%) of the water absorbent resin particles of the present invention is 70 or more, more preferably 73 or more, and particularly preferably 75 or more. The higher the upper limit, the more preferable it is not particularly limited, but from the viewpoint of performance balance with other physical properties and productivity, it is preferably 95 or less, more preferably 90 or less. As a means for improving the water separation rate, it is conceivable to widen the specific surface area of the particles or adjust the balance between hydrophilicity and hydrophobicity inside or on the surface of the particles. As means for achieving the same, for example, a polymerization step, a kneading shredding step, a crosslinking step, and / or a combined use of a hydrophobic substance in a post-step after the crosslinking step, or the gel temperature in the step of kneading a hydrous gel Adjustment, raising the heating temperature during drying when dehydrating from the hydrogel, raising the heating temperature in the crosslinking step, lowering the weight average particle diameter and the like can be mentioned. The gel temperature in the step of kneading the hydrous gel is preferably 40 to 120 ° C., more preferably 50 to 110 ° C. from the viewpoint of dehydration efficiency and performance balance with other physical properties. The heating temperature for drying the water-containing gel during dehydration is preferably 100 to 300 ° C., more preferably 110 to 280 ° C., from the viewpoint of performance balance with other physical properties and productivity. Heating above 300 ° C. is not preferable because the water-absorbent resin particles undergo thermal deterioration. The heating temperature in the cross-linking step is preferably 100 to 230 ° C, more preferably 120 to 180 ° C. Within this range, it is considered that the hydrophobic substance melts, or the viscosity decreases to coat the surface of the absorbent resin particles, thereby preventing the gels from coalescing and increasing the number of reaction points with the dehydrating agent. Be done. The weight average particle diameter is preferably 150 μm to 500 μm, and more preferably 200 μm to 400 μm, from the viewpoint of the balance of performance between dehydration and other physical properties.
　本発明の吸水性樹脂粒子のイオン交換水による再膨潤倍率（％）は、下記式（２）で示される値であり、保水量測定後の膨潤ゲルを１．０重量％塩化カルシウム水溶液で脱水処理した後、イオン交換水により再度膨潤させた保水量と生理食塩水に対する保水量の比率から算出される。従って、イオン交換水による再膨潤倍率が低いほど、水での希釈下において脱水剤による脱水効果が維持されていることを意味する。
　イオン交換水による再膨潤倍率［％］＝（１．０重量％塩化カルシウム水溶液処理後のイオン交換水に対する保水量［ｇ／ｇ］）／（生理食塩水に対する保水量［ｇ／ｇ］×１００　　（２）
　なお、具体的な測定方法については後述する。 The re-swelling ratio (%) of the water-absorbent resin particles of the present invention with ion-exchanged water is a value represented by the following formula (2), and the swollen gel after water retention measurement is dehydrated with a 1.0 wt% calcium chloride aqueous solution. After the treatment, it is calculated from the ratio of the water retention amount re-swelled with ion-exchanged water and the water retention amount with respect to physiological saline. Therefore, the lower the re-swelling ratio with ion-exchanged water, the more the dehydration effect of the dehydrating agent is maintained under dilution with water.
Re-swelling ratio with ion-exchanged water [%] = (Water retention amount [g / g] against ion-exchanged water after treatment with 1.0 wt% calcium chloride aqueous solution) / (Water retention amount against physiological saline [g / g] × 100 (2)
The specific measuring method will be described later.
　本発明の吸水性樹脂粒子のイオン交換水による再膨潤倍率（％）は脱水処理の効率性の観点から、１１０以下であり、より好ましくは１０５以下である。下限値は低いほど好ましく特に制限されないが、吸収性能とのバランスや生産性の観点から、好ましくは８０以上である。再膨潤倍率を低下させるための手段としては、粒子の比表面積を広げることや粒子内又は粒子表面の親水性と疎水性のバランスを調整することや、粒子内部のアニオン濃度を上げたり、脱水剤処理後の吸水性樹脂粒子の表面積を小さく保つことが考えられる。具体的には、重合工程、混練細断工程、架橋工程、又は架橋工程後の後工程において疎水性物質を併用することや、含水ゲルから脱水する際の乾燥時の加熱温度を上げること、重量平均粒子径を小さくすることなどが挙げられる。疎水性物質が吸収性樹脂粒子表面に存在することで、吸水樹脂粒子とその周囲に存在する水が接触することを妨げると想定され、結果としてゲルの再膨潤を抑止すると考えられる。 The re-swelling ratio (%) of the water-absorbent resin particles of the present invention with ion-exchanged water is 110 or less, more preferably 105 or less, from the viewpoint of the efficiency of dehydration treatment. The lower limit is preferably as low as possible and is not particularly limited, but is preferably 80 or more from the viewpoint of balance with the absorption performance and productivity. As means for reducing the re-swelling ratio, widening the specific surface area of the particles, adjusting the balance between hydrophilicity and hydrophobicity inside or on the particles, increasing the anion concentration inside the particles, and a dehydrating agent It is considered that the surface area of the water absorbent resin particles after the treatment is kept small. Specifically, in the polymerization step, kneading and shredding step, crosslinking step, or in the post-step after the crosslinking step, a hydrophobic substance is used in combination, or the heating temperature during drying when dehydrating from the hydrous gel is increased, Examples include reducing the average particle size. It is presumed that the presence of the hydrophobic substance on the surface of the absorbent resin particles prevents contact between the water absorbent resin particles and water existing around them, and as a result, it is considered that re-swelling of the gel is suppressed.
　本発明の１．０重量％塩化カルシウム水溶液のゲル通液速度は、下記式で示される値であり、生理食塩水で膨潤させた測定試料のゲルを、膨潤に使用した液の一部と共に８０ｍｌの１．０％重量塩化カルシウム水溶液に入れて、２０ｍｌの生理食塩水と塩化カルシウムの混合水溶液が、膨潤ゲルの間を流れ落ちる時間（Ｔ３；秒）から、２０ｍｌの生理食塩水と塩化カルシウムの混合水溶液が測定試料の無い状態で流れ落ちる時間（Ｔ４；秒）を差し引いた値から算出される。従って、０．１重量％塩化カルシウム水溶液のゲル通液速度が大きいほど、脱水剤が膨潤し、凝集した吸水性樹脂の粒子間に浸透しやすく、脱水効率が優れていることを意味する。
１．０重量％塩化カルシウム水溶液のゲル通液速度（ｍｌ／分）＝２０ｍｌ×６０／（Ｔ３－Ｔ４）
なお、具体的な測定方法については後述する。 The gel permeation rate of the 1.0 wt% calcium chloride aqueous solution of the present invention is a value represented by the following formula, and the gel of the measurement sample swollen with physiological saline is 80 ml together with a part of the liquid used for the swelling. 20% physiological saline and calcium chloride mixed solution of 20 ml physiological saline and calcium chloride from the time (T3; second) flowing down between the swollen gels. It is calculated from the value obtained by subtracting the time (T4; seconds) in which the aqueous solution flows down in the absence of the measurement sample. Therefore, the higher the gel flow rate of the 0.1 wt% calcium chloride aqueous solution is, the more the dehydrating agent swells and the more easily it permeates between the aggregated particles of the water absorbent resin, which means that the dehydrating efficiency is excellent.
Gel flow rate of 1.0 wt% calcium chloride aqueous solution (ml / min) = 20 ml × 60 / (T3-T4)
The specific measuring method will be described later.
　本発明の吸水性樹脂粒子の１．０重量％塩化カルシウム水溶液のゲル通液速度（ｍｌ／分）は脱水処理の効率性の観点から、２００以上であり、より好ましくは３００以上、特に好ましくは５００以上である。上限値は高いほど好ましく特に制限されないが、他物性との性能バランスや生産性の観点から、好ましくは２３００以下、より好ましくは２０００以下である。１．０重量％塩化カルシウムの水溶液ゲル通液速度は、粒子の比表面積を広げることや粒子内又は粒子表面の親水性と疎水性のバランスを調整することで制御される。 The gel permeation rate (ml / min) of the 1.0 wt% calcium chloride aqueous solution of the water absorbent resin particles of the present invention is 200 or more, more preferably 300 or more, and particularly preferably from the viewpoint of the efficiency of the dehydration treatment. It is 500 or more. The higher the upper limit, the more preferable it is not particularly limited, but from the viewpoint of performance balance with other physical properties and productivity, it is preferably 2300 or less, and more preferably 2000 or less. The gel permeation rate of an aqueous 1.0 wt% calcium chloride solution solution is controlled by increasing the specific surface area of the particles and adjusting the balance between hydrophilicity and hydrophobicity inside or on the surface of the particles.
　本発明の吸水性樹脂粒子の荷重下吸収量（ｇ／ｇ）は１９以上であることが好ましい。１９未満であると、繰り返し使用時に漏れが生じやすく好ましくない。また、上限値は高いほど好ましく特に制限されないが、他物性との性能バランスや生産性の観点から、好ましくは２７以下、より好ましくは２５以下である。荷重下吸収量は、架橋剤（ｂ）および表面架橋剤（ｅ）の種類と量で適宜調整することができる。従って、例えば、荷重下吸収量を上げる必要がある場合、架橋剤（ｂ）および表面架橋剤（ｅ）の使用量を上げることで容易に実現することができる。 The absorption amount under load (g / g) of the water-absorbent resin particles of the present invention is preferably 19 or more. If it is less than 19, leakage is likely to occur during repeated use, which is not preferable. Further, the higher the upper limit value, the more preferable it is not particularly limited, but it is preferably 27 or less, more preferably 25 or less from the viewpoint of performance balance with other physical properties and productivity. The absorption amount under load can be appropriately adjusted by the types and amounts of the crosslinking agent (b) and the surface crosslinking agent (e). Therefore, for example, when it is necessary to increase the absorption amount under load, it can be easily realized by increasing the amounts of the crosslinking agent (b) and the surface crosslinking agent (e) used.
　本発明の衛生用品は、本発明の吸水性樹脂粒子を含み、使用済品からの水分の脱水処理が容易である。衛生用品としては、例えば、紙おむつ、生理用ナプキン等が挙げられるが、衛生用品のみならず、各種水性液体の吸収剤や保持剤用途、ゲル化剤用途等の各種用途に使用されるものとして適用可能である。衛生用品の製造方法等は、公知のもの（特開２００３－２２５５６５号公報、特開２００６－１３１７６７号公報及び特開２００５－０９７５６９号公報等に記載のもの）と同様である。 The hygiene article of the present invention contains the water-absorbent resin particles of the present invention, and dehydration treatment of water from a used article is easy. Examples of hygiene products include paper diapers, sanitary napkins, etc., but not limited to hygiene products, they are also used as absorbents and retainers for various aqueous liquids and as gelling agents. It is possible. The method for manufacturing hygiene products and the like are the same as known methods (the methods described in JP-A-2003-225565, JP-A-2006-131767 and JP-A-2005-097569).
　本発明の衛生用品は、吸収体として吸水性樹脂粒子を単独で用いても良く、他の材料と共に用いて吸収体としても良い。他の材料としては繊維状物等が挙げられる。繊維状物と共に用いた場合の吸収体の構造及び製造方法等は、公知のもの（特開２００３－２２５５６５号公報、特開２００６－１３１７６７号公報及び特開２００５－０９７５６９号公報等）と同様である。 In the hygiene article of the present invention, the water-absorbent resin particles may be used alone as the absorber, or may be used together with other materials as the absorber. Examples of other materials include fibrous materials. The structure and manufacturing method of the absorbent when used together with the fibrous material are the same as known ones (JP 2003-225565 A, JP 2006-131767 A, JP 2005-097569 A, etc.). is there.
　吸水性樹脂粒子を、繊維状物と共に吸収体とする場合、吸水性樹脂粒子と繊維の重量比率（吸水性樹脂粒子の重量／繊維の重量）は３０／７０～９０／１０が好ましく、更に好ましくは４０／６０～７０／３０である。上記繊維状物としては、セルロース系繊維、有機系合成繊維及びセルロース系繊維と有機系合成繊維との混合物等が挙げられる。 When the water-absorbent resin particles are used as an absorbent body together with the fibrous material, the weight ratio of the water-absorbent resin particles to the fibers (weight of water-absorbent resin particles / weight of fibers) is preferably 30/70 to 90/10, and more preferably Is 40/60 to 70/30. Examples of the fibrous material include cellulosic fibers, organic synthetic fibers, and a mixture of cellulosic fibers and organic synthetic fibers.
　次に、本発明の衛生用品の処理方法について説明する。本発明の衛生用品の処理方法は、吸水性樹脂粒子を含み、使用済となった衛生用品の処理方法であって、使用済みとなった衛生用品を粉砕する工程（以下、「粉砕工程」と称する）と、衛生用品又は粉砕された衛生用品に含まれる吸水性樹脂粒子を脱水剤により脱水処理する工程（以下、脱水工程と称する）、粉砕及び脱水処理された衛生用品を水と混合して固液処理装置に輸送する工程（以下、「輸送工程」と称する）を含む。上記衛生用品は、さらにパルプ繊維を含んでいてもよい。 Next, a method for treating the hygiene article of the present invention will be described. The method for treating a hygienic article of the present invention is a method for treating a used hygiene article containing water-absorbent resin particles, wherein the step of pulverizing the used hygiene article (hereinafter, referred to as "crushing step"). A), a step of dehydrating the water-absorbent resin particles contained in the hygiene article or the crushed hygiene article with a dehydrating agent (hereinafter referred to as a dehydration step), and mixing the pulverized and dehydrated hygiene article with water. It includes a step of transporting to a solid-liquid processing apparatus (hereinafter referred to as "transporting step"). The hygiene article may further include pulp fibers.
　粉砕工程は、衛生用品を粉砕して粉砕物を得る工程である。粉砕は公知の粉砕機又は破砕機を使用することができ、例えば生ごみ粉砕機に使われているディスポーザー型破砕機（高速回転するターンテーブルで該衛生用品を壁面に飛ばし、ターンテーブル周縁部についている固定式、又は可変式のハンマーと壁面の固定刃等で破砕）、カッターミル、一軸型破砕機、二軸型破砕機、同軸心型破砕機、ハンマー式破砕機、ボールミル等が挙げられるが、衛生用品の素材にはプラスチック製のシートや不織布、伸縮性のある材料が含まれることから、高速回転しながら刃で切断するディスポーザー型破砕機やカッターミルが特に好適である。 The crushing process is a process of crushing sanitary goods to obtain a crushed product. For crushing, a known crusher or crusher can be used. For example, a disposer type crusher used in a food waste crusher (a sanitary article is blown to a wall surface by a high-speed rotating turntable, A fixed type or variable type hammer and a fixed blade on the wall), a cutter mill, a single-axis type crusher, a twin-axis type crusher, a coaxial type crusher, a hammer type crusher, a ball mill, etc. Since the hygiene products include plastic sheets, non-woven fabrics, and elastic materials, a disposer type crusher or a cutter mill that cuts with a blade while rotating at high speed is particularly suitable.
　衛生用品の粉砕物は、水性懸濁液としてもよい。水性懸濁液を得る方法としては、水を加えて衛生用品を膨潤させた後粉砕する方法、粉砕しながら水を加えて粉砕する方法、粉砕後に水を加える方法があるが、粉砕機への負荷低減の観点から、水を加えて衛生用品を膨潤させた後粉砕する方法が好ましい。 The crushed product of sanitary goods may be an aqueous suspension. As a method for obtaining an aqueous suspension, there are a method of swelling hygiene products by adding water and then pulverizing, a method of pulverizing by adding water while pulverizing, and a method of adding water after pulverizing. From the viewpoint of reducing the load, a method of swelling the sanitary article by adding water and then pulverizing is preferred.
　粉砕後の衛生用品の粉砕物の大きさの好適な範囲は、後述する固液分離装置による分離回収方式にも依存するが、水流での輸送性の観点から、好ましくは衛生用品の一片の長さが１００ｍｍ以下である。粉砕物の大きさは、前述した粉砕機又は破砕機の種類、及び処理条件等により適宜調整可能である。 A suitable range of the size of the pulverized product of the sanitary article after pulverization depends on the separation / collection method by the solid-liquid separation device described later, but from the viewpoint of transportability in a water stream, the length of one piece of the sanitary article is preferable. Is 100 mm or less. The size of the crushed product can be appropriately adjusted depending on the type of the crusher or the crusher described above, the processing conditions, and the like.
　なお、粉砕に供する衛生用品は、衛生用品をそのまま粉砕しても、衛生用品から吸水性樹脂粒子を含有する吸収体を取り出して粉砕しても良い。 As for the sanitary goods to be crushed, the sanitary goods may be crushed as they are, or the absorbent body containing the water-absorbent resin particles may be taken out from the sanitary goods and crushed.
　脱水工程は、衛生用品又は粉砕された衛生用品に含まれる吸水性樹脂粒子を脱水剤により脱水処理する工程である。本脱水処理により吸水性樹脂粒子の吸水能が低下し、吸水性樹脂粒子の含水率及び体積が低下する。その結果、吸水性樹脂粒子のゲル弾性が向上し、分離回収効率が向上する。なお、本発明における脱水工程には、吸水性樹脂粒子を脱水剤により脱水する工程だけでなく、実際に脱水現象が生じておらず、単に脱水剤を添加する工程も含まれる。 The dehydration step is a step of dehydrating the water-absorbent resin particles contained in the sanitary goods or crushed sanitary goods with a dehydrating agent. By this dehydration treatment, the water absorbing ability of the water absorbent resin particles is reduced, and the water content and volume of the water absorbent resin particles are reduced. As a result, the gel elasticity of the water absorbent resin particles is improved, and the separation and recovery efficiency is improved. The dehydration step in the present invention includes not only the step of dehydrating the water-absorbent resin particles with a dehydrating agent but also the step of simply adding the dehydrating agent without actually causing the dehydration phenomenon.
　本発明における脱水剤は、脱水性能を持つ化合物であれば特に限定なく、公知の脱水剤としては水溶性多価金属化合物、強酸等が挙げられる。水溶性多価金属化合物は、カルボキシル基、又はカルボキシル基イオンとキレート塩を形成すること、あるいは強酸によってカルボキシル基イオンがカルボキシル基に変換されることによって、吸水性樹脂粒子内部と周囲の水とのイオン濃度の差が低下することにより浸透圧差も低下し、結果として吸水性樹脂粒子内部からの脱水が生じる。脱水剤としては、脱水効率、およびハンドリングの観点から好ましくは、水溶性多価金属化合物である。 The dehydrating agent in the present invention is not particularly limited as long as it is a compound having dehydrating performance, and known dehydrating agents include water-soluble polyvalent metal compounds, strong acids and the like. The water-soluble polyvalent metal compound forms a chelate salt with a carboxyl group, or a carboxyl group ion, or by converting a carboxyl group ion to a carboxyl group by a strong acid, the water-absorbent resin particles have a As the difference in ion concentration decreases, the difference in osmotic pressure also decreases, resulting in dehydration from inside the water-absorbent resin particles. The dehydrating agent is preferably a water-soluble polyvalent metal compound from the viewpoint of dehydration efficiency and handling.
　水溶性多価金属化合物は、周期表において２以上の価数を有する元素であって、水へ溶解又は水と反応後にカルボキシル基、又はカルボキシル基イオンとキレート塩を形成する水溶性多価金属化合物であれば、特に制限されない。２価金属化合物としては、例えば、マグネシウム、カルシウム、ストロンチウム、バリウム等のアルカリ土類金属を含む多価金属化合物、鉄、ニッケル、銅、亜鉛等の遷移金属を含む多価金属化合物等が挙げられ、３価金属としては、例えば、ホウ素、アルミニウム、ガリウム等の金属を含む多価金属化合物が挙げられる。なお、多価金属化合物は、非水和物であっても、一水和物、二水和物、三水和物、四水和物、五水和物、六水和物、七水和物、八水和物、九水和物のような水和物であってもよい。これらの脱水剤は単独で使用してもよく、２種以上を併用してもよい。なお、発明において「水溶性多価金属化合物」とは、２０℃の水に対する溶解度が１ｍｇ／ｍｌ以上であり、好ましくは１０ｍｇ／ｍｌ以上である多価金属化合物を示す。 The water-soluble polyvalent metal compound is an element having a valence of 2 or more in the periodic table, and forms a carboxyl group or a chelate salt with a carboxyl group ion after dissolving in water or reacting with water. If so, there is no particular limitation. Examples of the divalent metal compound include polyvalent metal compounds containing alkaline earth metals such as magnesium, calcium, strontium and barium, and polyvalent metal compounds containing transition metals such as iron, nickel, copper and zinc. Examples of the trivalent metal include polyvalent metal compounds containing metals such as boron, aluminum and gallium. Incidentally, the polyvalent metal compound, even if non-hydrated, monohydrate, dihydrate, trihydrate, tetrahydrate, pentahydrate, hexahydrate, heptahydrate It may be a hydrate such as a monohydrate, an octahydrate or a nonahydrate. These dehydrating agents may be used alone or in combination of two or more kinds. In the present invention, the “water-soluble polyvalent metal compound” refers to a polyvalent metal compound having a solubility in water at 20 ° C. of 1 mg / ml or more, preferably 10 mg / ml or more.
　マグネシウムを含む水溶性多価金属化合物としては、硫酸マグネシウム、硝酸マグネシウム、塩化マグネシウム、臭化マグネシウム、ヨウ化マグネシウム、過塩素酸マグネシウム、過マンガン酸マグネシウム、酢酸マグネシウム等が挙げられる。 Examples of water-soluble polyvalent metal compounds containing magnesium include magnesium sulfate, magnesium nitrate, magnesium chloride, magnesium bromide, magnesium iodide, magnesium perchlorate, magnesium permanganate, magnesium acetate and the like.
　カルシウムを含む水溶性多価金属化合物としては、酸化カルシウム、過酸化カルシウム、水酸化カルシウム、フッ化カルシウム、塩化カルシウム、臭化カルシウム、ヨウ化カルシウム、水素化カルシウム、炭化カルシウム、リン化カルシウム、炭酸カルシウム、硝酸カルシウム、亜硫酸カルシウム、ケイ酸カルシウム、リン酸カルシウム、ピロリン酸カルシウム、次亜塩素酸カルシウム、塩素酸カルシウム、過塩素酸カルシウム、臭素酸カルシウム、ヨウ素酸カルシウム、クロム酸カルシウム、酢酸カルシウム、グルコン酸カルシウム、安息香酸カルシウム、ステアリン酸カルシウム等が含まれる。 Examples of the water-soluble polyvalent metal compound containing calcium include calcium oxide, calcium peroxide, calcium hydroxide, calcium fluoride, calcium chloride, calcium bromide, calcium iodide, calcium hydride, calcium carbide, calcium phosphide, and carbonic acid. Calcium, calcium nitrate, calcium sulfite, calcium silicate, calcium phosphate, calcium pyrophosphate, calcium hypochlorite, calcium chlorate, calcium perchlorate, calcium bromate, calcium iodate, calcium chromate, calcium acetate, calcium gluconate. , Calcium benzoate, calcium stearate and the like.
　これらの脱水剤のうち、脱水性向上の観点から、２価の水溶性多価金属化合物が好ましく、より好ましくはマグネシウムを含む水溶性多価金属化合物及びカルシウムを含む水溶性多価金属化合物、さらに好ましくは塩化カルシウム、酸化カルシウム、酢酸カルシウム、及び次亜塩素酸カルシウムである。 Among these dehydrating agents, a divalent water-soluble polyvalent metal compound is preferable, more preferably a water-soluble polyvalent metal compound containing magnesium and a water-soluble polyvalent metal compound containing calcium, from the viewpoint of improving the dehydration property. Preferred are calcium chloride, calcium oxide, calcium acetate, and calcium hypochlorite.
　脱水剤で処理する方法は、衛生用品中の吸水性樹脂粒子と脱水剤が接触する方法であれば特に限定されないが、固体状の脱水剤を衛生用品に添加してもよいし、脱水剤の水溶液を添加してもよい。また、脱水剤で処理される衛生用品については、事前に水で膨潤させてから脱水剤を添加してもよいし、脱水剤添加後に水を添加してもよい。脱水剤で処理する装置については、衛生用品と脱水剤を混合することができる装置であればよく、前述した粉砕機及び破砕機で処理してもよいし、別途攪拌可能な処理槽で実施してもよい。 The method of treating with a dehydrating agent is not particularly limited as long as it is a method in which the water-absorbent resin particles in the sanitary article come into contact with the dehydrating agent, but a solid dehydrating agent may be added to the sanitary article, or An aqueous solution may be added. In addition, sanitary goods treated with a dehydrating agent may be swollen with water in advance and then added with the dehydrating agent, or water may be added after adding the dehydrating agent. As for the apparatus for treating with a dehydrating agent, any apparatus capable of mixing a hygiene article and a dehydrating agent may be used, and may be treated with the above-mentioned pulverizer and crusher, or may be separately treated with a stirring treatment tank. May be.
　脱水工程で使用する脱水剤の量は、使用する脱水剤の種類にもよるが、吸水性樹脂粒子の乾燥重量に対して好ましくは０．１％以上であり、更に好ましくは１．０％以上、より好ましくは３．０％以上である。脱水剤の量が少ないと、吸水性樹脂粒子の離水率が低下し、分離回収効率が低下する。 The amount of the dehydrating agent used in the dehydrating step depends on the type of the dehydrating agent used, but is preferably 0.1% or more, more preferably 1.0% or more, based on the dry weight of the water absorbent resin particles. , And more preferably 3.0% or more. When the amount of the dehydrating agent is small, the water separation rate of the water-absorbent resin particles decreases, and the separation and recovery efficiency decreases.
　前述した粉砕工程と脱水工程の工程順は、衛生用品を粉砕する工程と衛生用品又は粉砕された衛生用品に含まれる吸水性粒子を脱水剤により脱水処理する工程を順次又は同時に実施することができる。以下に、具体的な処理工程の順序を示す。矢印は順序を示す。
（１）衛生用品を粉砕する工程→粉砕された衛生用品に含まれる吸水性樹脂粒子を脱水剤により脱水処理する工程→粉砕及び脱水処理された衛生用品を水と混合して固液処理装置に輸送する工程。
（２）衛生用品に含まれる吸水性樹脂粒子を脱水剤により脱水処理する工程→衛生用品を粉砕する工程→粉砕及び脱水処理された衛生用品を水と混合して固液処理装置に輸送する工程。
（３）衛生用品又は粉砕された衛生用品に含まれる吸水性樹脂粒子を脱水剤により脱水処理する工程と、衛生用品を粉砕する工程を同時に実施する工程→粉砕及び脱水処理された衛生用品を水と混合して固液処理装置に輸送する工程。 Regarding the order of the above-mentioned pulverization step and dehydration step, the step of pulverizing the hygiene article and the step of dehydrating the hygiene article or the water-absorbent particles contained in the pulverized hygiene article with the dehydrating agent can be carried out sequentially or simultaneously. .. The specific order of the processing steps is shown below. Arrows indicate order.
(1) Step of crushing sanitary goods → Step of dehydrating water-absorbent resin particles contained in the crushed sanitary goods with a dehydrating agent → Mixing crushed and dehydrated sanitary goods with water into a solid-liquid treatment device The process of transporting.
(2) Process of dehydrating water-absorbent resin particles contained in sanitary goods with a dehydrating agent → Process of crushing sanitary goods → Process of mixing crushed and dehydrated sanitary goods with water and transporting to solid-liquid treatment device ..
(3) A step of dehydrating the water-absorbent resin particles contained in the sanitary goods or the crushed sanitary goods with a dehydrating agent and a step of crushing the sanitary goods at the same time → watering the crushed and dehydrated sanitary goods The process of mixing with and transporting to a solid-liquid processing apparatus.
　輸送工程は、粉砕及び脱水処理された衛生用品を水と混合して下流の固液処理装置に輸送する工程である。衛生用品粉砕物、好ましくは水性懸濁液が、給水手段により水流で固液処理装置に輸送される。 The transportation process is a process in which the crushed and dehydrated sanitary goods are mixed with water and transported to the downstream solid-liquid treatment device. The hygiene product crush, preferably an aqueous suspension, is transported by water supply to the solid-liquid treatment device by means of a water supply means.
　輸送工程における輸送手段は、ポンプ式又は自然流下式により固液処理装置に輸送することができるが、粉砕及び脱水処理された衛生用品が配管又はホースを経由して、水流で固液分離装置に輸送することが好ましい。配管又はホースの種類としては、銅管、鉛管、鉄管、硬質ポリ塩化ビニル管、ポリエチレン管、硬質塩化ビニルライニング管、ステンレス管、白管、土管、耐火二層管等が含まれる。 The transportation means in the transportation process can be transported to the solid-liquid treatment device by a pump method or a natural flow-down method, but the crushed and dehydrated sanitary ware is passed through pipes or hoses to the solid-liquid separation device by water flow. It is preferably shipped. The types of pipes or hoses include copper pipes, lead pipes, iron pipes, hard polyvinyl chloride pipes, polyethylene pipes, hard vinyl chloride lining pipes, stainless pipes, white pipes, earth pipes, fire-resistant double-layer pipes, and the like.
　固液処理装置としては、公知の固液分離処理装置が使用できる。例えば、スクリーン分離、沈殿分離、膜分離、遠心分離等が挙げられる。 As the solid-liquid treatment device, a known solid-liquid separation treatment device can be used. For example, screen separation, precipitation separation, membrane separation, centrifugation and the like can be mentioned.
　本発明の衛生用品の処理方法としての好ましい実施形態の一つとして、ディスポーザー排水処理システムが挙げられる。ディスポーザー排水処理とは、通常、生ゴミを台所のシンク排水口に取り付けたディスポーザーで粉砕し、給水による排水とともに下水道や浄化槽に放流するシステムであり、ゴミを低減し、衛生面及び利便性に優れる排水処理システムであり、特に集合住宅等に広く普及が進んでいる。前記排水処理システムを衛生用品に展開するためには、吸水性樹脂粒子の水膨潤性を低減させ、排水管内での堆積や付着による排水不良や配管閉塞を防止することが重要であるが、本発明の処理方法は、このような課題を解決できるため、好ましい。 A disposer wastewater treatment system is mentioned as one of the preferred embodiments of the method for treating sanitary goods of the present invention. Disposer wastewater treatment is a system that normally crushes raw garbage with a disposer attached to the sink drain of the kitchen and discharges it to the sewer or septic tank together with the drainage of water supply, which reduces waste and is excellent in hygiene and convenience. This is a wastewater treatment system, and it is spreading widely especially in apartment houses. In order to develop the wastewater treatment system into sanitary ware, it is important to reduce the water swelling property of the water-absorbent resin particles and prevent defective drainage and pipe clogging due to accumulation and adhesion in the drainage pipe. The treatment method of the invention is preferable because it can solve such a problem.
　本発明の衛生用品の処理方法は、粉砕及び脱水処理された衛生物品が固液処理装置に輸送された後、固液分離装置により粉砕及び脱水処理された吸水性樹脂粒子を含む衛生用品が回収される。本発明の衛生用品の処理方法で得られる衛生用品の回収物は含水率が低いという特徴を有するため、焼却処理時の燃焼効率が優れるだけでなく、固形燃料等としてリサイクル利用をすることができる。したがって、本発明には、前記衛生用品の処理方法で得られた衛生物品回収物及び固形燃料の製造方法が含まれる。前記固形燃料としてリサイクル利用をする場合は、前記衛生用品の回収物をさらに乾燥することが好ましい。 The method for treating hygiene products of the present invention is such that after the pulverized and dehydrated hygiene article is transported to the solid-liquid treatment device, the hygiene product containing the water-absorbent resin particles pulverized and dehydrated by the solid-liquid separation device is recovered. To be done. Since the recovered hygiene product obtained by the method for treating hygiene products of the present invention has a feature of having a low water content, not only the combustion efficiency during incineration treatment is excellent, but it can also be recycled as a solid fuel or the like. .. Therefore, the present invention includes a method for producing a sanitary article recovery product and a solid fuel obtained by the method for treating a hygiene article. When recycled as the solid fuel, it is preferable to further dry the collected sanitary goods.
　以下、実施例及び比較例により本発明をさらに説明するが、本発明はこれらに限定されるものではない。なお、特に定めない限り、部は重量部、％は重量％を示す。なお、吸水性樹脂粒子の生理食塩水に対する保水量、離水率、荷重下吸収量、生理食塩水のゲル通液速度、１．０重量％塩化カルシウム水溶液のゲル通液速度は以下の方法により測定した。 The present invention will be further described below with reference to examples and comparative examples, but the present invention is not limited to these. Unless otherwise specified, parts are parts by weight and% is% by weight. The water retention capacity of water-absorbent resin particles with respect to physiological saline, the water separation rate, the absorption amount under load, the gel permeation rate of physiological saline, and the gel permeation rate of a 1.0 wt% calcium chloride aqueous solution are measured by the following methods. did.
＜生理食塩水に対する保水量の測定方法＞
　目開き６３μｍ（ＪＩＳ　Ｚ８８０１－１：２００６）のナイロン網で作製したティーバッグ（縦２０ｃｍ、横１０ｃｍ）に測定試料１．００ｇを入れ、生理食塩水（食塩濃度０．９％）１，０００ｍｌ中に無撹拌下、１時間浸漬した後引き上げて、１５分間吊るして水切りした。その後、ティーバッグごと、遠心分離器にいれ、１５０Ｇで９０秒間遠心脱水して余剰の生理食塩水を取り除き、ティーバッグを含めた重量（ｈ１）を測定し次式から保水量を求めた。なお、使用した生理食塩水及び測定雰囲気の温度は２５℃±２℃とした。（ｈ２）は、測定試料の無い場合について上記と同様の操作により計測したティーバッグの重量である。
保水量（ｇ／ｇ）＝（ｈ１）－（ｈ２） <Measurement method of water retention amount for physiological saline>
1.00 g of the measurement sample was put into a tea bag (length 20 cm, width 10 cm) made of a nylon net having an opening of 63 μm (JIS Z8801-1: 2006), and in 1,000 ml of physiological saline (saline concentration 0.9%). It was soaked for 1 hour without stirring and then pulled up and hung for 15 minutes to drain water. Then, each tea bag was put in a centrifuge, spin-dried at 150 G for 90 seconds to remove excess physiological saline, and the weight (h1) including the tea bag was measured to determine the water retention amount from the following formula. The temperature of the physiological saline used and the measurement atmosphere was 25 ° C ± 2 ° C. (H2) is the weight of the tea bag measured by the same operation as above in the case where there is no measurement sample.
Water retention (g / g) = (h1)-(h2)
＜離水率の測定方法＞
　前記の保水量の測定後に、以下の操作を続けて実施した。即ち、遠心分離器測定後のティーバックを、１．０重量％塩化カルシウム水溶液５００ｍｌ中に無撹拌下、５分間浸漬した後引き上げて、ティーバッグごと、遠心分離器にいれ、１５０Ｇで９０秒間遠心脱水して余剰の塩化カルシウム水溶液を取り除き、ティーバッグを含めた重量（ｈ３）を測定し次式から１．０重量％塩化カルシウム水溶液処理後の保水量を求めた。（ｈ４）は、測定試料の無い場合について上記と同様の操作により計測したティーバッグの重量である。
　１．０％塩化カルシウム水溶液処理後の保水量（ｇ／ｇ）＝（ｈ３）－（ｈ４）
　その後、下式により離水率を求めた。
　離水率（％）＝（１－１．０重量％塩化カルシウム水溶液処理後の保水量）／（生理食塩水に対する保水量）×１００ <Measurement method of water separation rate>
The following operation was continuously performed after the measurement of the water retention amount. That is, the tea bag after the centrifuge measurement was immersed in 500 ml of a 1.0 wt% calcium chloride aqueous solution without stirring for 5 minutes, then pulled up, put in a centrifuge together with the tea bag, and centrifuged at 150 G for 90 seconds. The excess calcium chloride aqueous solution was removed by dehydration, the weight (h3) including the tea bag was measured, and the water retention after treatment with the 1.0 wt% calcium chloride aqueous solution was determined from the following formula. (H4) is the weight of the tea bag measured by the same operation as above in the case where there is no measurement sample.
Water retention after treatment with 1.0% aqueous calcium chloride solution (g / g) = (h3)-(h4)
Then, the water separation rate was calculated by the following formula.
Water separation rate (%) = (1-1.0 wt% water retention after treatment with calcium chloride aqueous solution) / (water retention relative to physiological saline) x 100
＜イオン交換水による再膨潤倍率の測定方法＞
　前記の離水率の測定後に、以下の操作を続けて実施した。即ち、遠心脱水後のティーバックを、イオン交換水溶液５００ｍｌ中に無撹拌下、５分間浸漬した後引き上げて、ティーバッグごと、遠心分離器にいれ、１５０Ｇで９０秒間遠心脱水して余剰のイオン交換水溶液を取り除き、ティーバッグを含めた重量（ｈ５）を測定し次式からイオン交換水処理後の保水量を求めた。（ｈ６）は、測定試料の無い場合について上記と同様の操作により計測したティーバッグの重量である。
　１．０重量％塩化カルシウム水溶液処理後のイオン交換水に対する保水量［ｇ／ｇ］＝（ｈ５）－（ｈ６）
　その後、下式によりイオン交換水による再膨潤倍率を求めた。
　イオン交換水による再膨潤倍率［％］＝（１．０重量％塩化カルシウム水溶液処理後のイオン交換水に対する保水量［ｇ／ｇ］）／（生理食塩水に対する保水量［ｇ／ｇ］）｝×１００ <Method of measuring re-swelling ratio with ion-exchanged water>
After the measurement of the water separation rate, the following operation was continuously performed. That is, the tea bag after centrifugal dehydration is immersed in 500 ml of an ion-exchange aqueous solution without stirring for 5 minutes, then pulled up, put in a centrifuge together with the tea bag, and spin-dried at 150 G for 90 seconds to remove excess ion exchange. The aqueous solution was removed, the weight (h5) including the tea bag was measured, and the water retention amount after the ion-exchanged water treatment was obtained from the following formula. (H6) is the weight of the tea bag measured by the same operation as above in the case where there is no measurement sample.
Water retention capacity against ion-exchanged water after treatment with 1.0 wt% calcium chloride aqueous solution [g / g] = (h5)-(h6)
Then, the re-swelling ratio with ion-exchanged water was calculated by the following formula.
Re-swelling ratio with ion-exchanged water [%] = (Water retention amount [g / g] for ion-exchanged water after treatment with 1.0 wt% calcium chloride aqueous solution) / (Water retention amount for physiological saline [g / g])} × 100
＜荷重下吸収量の測定方法＞
　目開き６３μｍ（ＪＩＳ　Ｚ８８０１－１：２００６）のナイロン網を底面に貼った円筒型プラスチックチューブ（内径：２５ｍｍ、高さ：３４ｍｍ）内に、標準ふるいを用いて２５０～５００μｍの範囲にふるい分けした測定試料０．１６ｇを秤量し、円筒型プラスチックチューブを垂直にしてナイロン網上に測定試料がほぼ均一厚さになるように整えた後、この測定試料の上に分銅（重量：３１０．６ｇ、外径：２４．５ｍｍ、）を乗せた。この円筒型プラスチックチューブ全体の重量（Ｍ１）を計量した後、生理食塩水（食塩濃度０．９％）６０ｍｌの入ったシャーレ（直径：１２ｃｍ）の中に測定試料及び分銅の入った円筒型プラスチックチューブを垂直に立ててナイロン網側を下面にして浸し、６０分静置した。６０分後に、円筒型プラスチックチューブをシャーレから引き上げ、これを斜めに傾けて底部に付着した水を一箇所に集めて水滴として垂らすことで余分な水を除去した後、測定試料及び分銅の入った円筒型プラスチックチューブ全体の重量（Ｍ２）を計量し、次式から荷重下吸収量を求めた。なお、使用した生理食塩水及び測定雰囲気の温度は２５℃±２℃とした。
　荷重下吸収量（ｇ／ｇ）＝｛（Ｍ２）－（Ｍ１）｝／０．１６ <Measurement method of absorption under load>
Measurement by sieving in a range of 250 to 500 μm using a standard sieve in a cylindrical plastic tube (inner diameter: 25 mm, height: 34 mm) having a nylon net with an opening of 63 μm (JIS Z8801-1: 2006) attached to the bottom surface. 0.16 g of the sample was weighed, and the cylindrical plastic tube was placed vertically to prepare a measurement sample on the nylon net so that the measurement sample had a substantially uniform thickness, and then a weight (weight: 310.6 g, external Diameter: 24.5 mm,) was mounted. After measuring the total weight (M1) of this cylindrical plastic tube, a cylindrical plastic containing a measurement sample and a weight in a petri dish (diameter: 12 cm) containing 60 ml of physiological saline (saline concentration 0.9%). The tube was erected vertically, the nylon mesh side was the lower surface, and the tube was immersed and left standing for 60 minutes. After 60 minutes, the cylindrical plastic tube was pulled up from the petri dish, the water adhering to the bottom was collected at one position by tilting it to remove excess water, and then the measurement sample and the weight entered. The weight (M2) of the entire cylindrical plastic tube was measured, and the absorption amount under load was calculated from the following formula. The temperature of the physiological saline used and the measurement atmosphere was 25 ° C ± 2 ° C.
Absorption under load (g / g) = {(M2)-(M1)} / 0.16
＜生理食塩水のゲル通液速度の測定方法＞
　図１及び図２で示される器具を用いて以下の操作により測定した。
　測定試料０．３２ｇを１５０ｍｌ生理食塩水１（食塩濃度０．９％）に３０分間浸漬して膨潤ゲル粒子２を調製した。そして、垂直に立てた円筒３｛直径（内径）２５．４ｍｍ、長さ４０ｃｍ、底部から６０ｍｌの位置及び４０ｍｌの位置にそれぞれ目盛り線４及び目盛り線５が設けてある。｝の底部に、金網６（目開き１０６μｍ、ＪＩＳ　Ｚ８８０１－１：２００６）と、開閉自在のコック７（通液部の内径５ｍｍ）とを有する濾過円筒管内に、コック７を閉鎖した状態で、調製した膨潤ゲル粒子２を生理食塩水と共に移した後、この膨潤ゲル粒子２の上に、金網面に対して垂直に結合する加圧軸９（重さ２２ｇ、長さ４７ｃｍ）を有する円形金網８（目開き１５０μｍ、直径２５ｍｍ）を、金網と膨潤ゲル粒子とが接触するように載せ、更に加圧軸９におもり１０（８８．５ｇ）を載せ、１分間静置した。引き続き、コック７を開き、濾過円筒管内の液面が６０ｍｌ目盛り線４から４０ｍｌ目盛り線５になるのに要する時間（Ｔ１；秒）を計測し、次式よりゲル通液速度（ｍｌ／ｍｉｎ）を求めた。
　ゲル通液速度（ｍｌ／ｍｉｎ）＝２０ｍｌ×６０／（Ｔ１－Ｔ２）
　なお、使用する生理食塩水及び測定雰囲気の温度は２５℃±２℃で行い、Ｔ２は測定試料の無い場合について上記と同様の操作により計測した時間である。 <Measurement method of gel permeation rate of physiological saline>
It measured by the following operations using the instrument shown in FIG. 1 and FIG.
A swollen gel particle 2 was prepared by immersing 0.32 g of the measurement sample in 150 ml of physiological saline 1 (saline concentration 0.9%) for 30 minutes. Then, a vertically standing cylinder 3 {diameter (inner diameter) 25.4 mm, length 40 cm, graduation line 4 and graduation line 5 are provided at a position of 60 ml and 40 ml from the bottom, respectively. }, In the state where the cock 7 is closed in a filtration cylindrical tube having a wire mesh 6 (opening 106 μm, JIS Z8801-1: 2006) and an openable / closable cock 7 (inner diameter of the liquid passage portion is 5 mm), After transferring the prepared swollen gel particles 2 together with physiological saline, a circular wire netting having a pressure shaft 9 (weight 22 g, length 47 cm) which is vertically connected to the wire netting surface is placed on the swollen gel particles 2. 8 (opening 150 μm, diameter 25 mm) was placed so that the wire mesh and the swollen gel particles were in contact with each other, and a weight 10 (88.5 g) was further placed on the pressure shaft 9 and allowed to stand for 1 minute. Subsequently, the cock 7 is opened, and the time (T1; seconds) required for the liquid level in the filtration cylindrical tube to change from the 60 ml scale line 4 to the 40 ml scale line 5 is measured, and the gel flow rate (ml / min) is calculated from the following formula. I asked.
Gel flow rate (ml / min) = 20 ml x 60 / (T1-T2)
The temperature of the physiological saline used and the measurement atmosphere are 25 ° C. ± 2 ° C., and T2 is the time measured by the same operation as above in the case where there is no measurement sample.
＜１．０重量％塩化カルシウム水溶液のゲル通液速度の測定方法＞
　図１及び図２で示される器具を用いて以下の操作により測定した。
　測定試料０．３２ｇを１５０ｍｌ生理食塩水１（食塩濃度０．９％）に３０分間浸漬して膨潤ゲル粒子２を調製した。そして、垂直に立てた円筒３｛直径（内径）２５．４ｍｍ、長さ４０ｃｍ、底部から６０ｍｌの位置及び４０ｍｌの位置にそれぞれ目盛り線４及び目盛り線５が設けてある。｝の底部に、金網６（目開き１０６μｍ、ＪＩＳ　Ｚ８８０１－１：２００６）と、開閉自在のコック７（通液部の内径５ｍｍ）とを有する濾過円筒管内に、コック７を閉鎖した状態にした。測定試料の調製に使用した生理食塩水のうち、上澄み液８０ｍｌを捨て、残った膨潤ゲル粒子２を生理食塩水と共に移した後、塩化カルシウム液８０ｍｌを円筒３の中に注入し、この膨潤ゲル粒子２の上に金網面に対して垂直に結合する加圧軸９（重さ２２ｇ、長さ４７ｃｍ）を有する円形金網８（目開き１５０μｍ、直径２５ｍｍ）を、金網と膨潤ゲル粒子とが接触するように載せ、更に加圧軸９におもり１０（８８．５ｇ）を載せ、１分間静置した。引き続き、コック７を開き、濾過円筒管内の液面が６０ｍｌ目盛り線４から４０ｍｌ目盛り線５になるのに要する時間（Ｔ３；秒）を計測し、次式よりゲル通液速度（ｍｌ／分）を求めた。
　１．０重量％塩化カルシウム水溶液のゲル通液速度（ｍｌ／分）＝２０ｍｌ×６０／（Ｔ３－Ｔ４）
　なお、使用する生理食塩水、１．０重量％塩化カルシウム水溶液及び測定雰囲気の温度は２５℃±２℃で行い、Ｔ４は測定試料の無い場合について上記と同様の操作により計測した時間である。 <Method for measuring gel permeation rate of 1.0 wt% calcium chloride aqueous solution>
It measured by the following operations using the instrument shown in FIG. 1 and FIG.
A swollen gel particle 2 was prepared by immersing 0.32 g of the measurement sample in 150 ml of physiological saline 1 (saline concentration 0.9%) for 30 minutes. Then, a vertically standing cylinder 3 {diameter (inner diameter) 25.4 mm, length 40 cm, graduation line 4 and graduation line 5 are provided at a position of 60 ml and 40 ml from the bottom, respectively. }, The cock 7 was closed in a filtration cylindrical tube having a wire mesh 6 (opening 106 μm, JIS Z8801-1: 2006) and an openable / closable cock 7 (inner diameter of the liquid passage portion was 5 mm). .. Of the physiological saline solution used for the preparation of the measurement sample, 80 ml of the supernatant was discarded, the remaining swollen gel particles 2 were transferred together with the physiological saline solution, and 80 ml of calcium chloride solution was poured into the cylinder 3 to obtain the swollen gel. A circular wire mesh 8 (opening 150 μm, diameter 25 mm) having a pressure shaft 9 (weight 22 g, length 47 cm) that is vertically bonded to the wire mesh surface is contacted with the wire mesh and the swollen gel particles. Then, the weight 10 (88.5 g) was placed on the pressure shaft 9 and left for 1 minute. Subsequently, the cock 7 is opened, and the time (T3; seconds) required for the liquid level in the filtration cylindrical tube to change from the 60 ml scale line 4 to the 40 ml scale line 5 is measured, and the gel flow rate (ml / min) is calculated from the following formula. I asked.
Gel flow rate of 1.0 wt% calcium chloride aqueous solution (ml / min) = 20 ml × 60 / (T3-T4)
The physiological saline solution, 1.0 wt% calcium chloride aqueous solution and the temperature of the measurement atmosphere were 25 ° C. ± 2 ° C., and T4 was the time measured by the same operation as above in the case of no measurement sample.
＜実施例１＞　水溶性ビニルモノマー（ａ１）｛アクリル酸｝１５７部（２．１８モル部）、内部架橋剤（ｂ）｛ペンタエリスリトールトリアリルエーテル｝０．６３０５部（０．００２４モル部）及び脱イオン水３４４．６５部を攪拌・混合しながら３℃に保った。この混合物中に窒素を流入して溶存酸素量を１ｐｐｍ以下とした後、１％過酸化水素水溶液０．６３部、２％アスコルビン酸水溶液１．１７７４部及び２％の２，２’－アゾビス［２－メチル－Ｎ－（２－ヒドロキシエチル）－プロピオンアミド］水溶液２．３５５部を添加・混合して重合を開始させた。混合物の温度が９０℃に達した後、９０±２℃で約５時間重合することにより含水ゲル（１）を得た。 <Example 1> Water-soluble vinyl monomer (a1) {acrylic acid} 157 parts (2.18 mol part), internal crosslinking agent (b) {pentaerythritol triallyl ether} 0.6305 part (0.0024 mol part) And 344.65 parts of deionized water were maintained at 3 ° C. with stirring and mixing. Nitrogen was introduced into this mixture to adjust the amount of dissolved oxygen to 1 ppm or less, and then 0.63 parts of a 1% aqueous hydrogen peroxide solution, 1.1774 parts of a 2% aqueous ascorbic acid solution and 2% of 2,2'-azobis [ 2-Methyl-N- (2-hydroxyethyl) -propionamide] aqueous solution (2.355 parts) was added and mixed to initiate polymerization. After the temperature of the mixture reached 90 ° C., the mixture was polymerized at 90 ± 2 ° C. for about 5 hours to obtain a hydrogel (1).
　次にこの含水ゲル（１）５０２．２７部をはさみで約１ｍｍ角に細分し、４８．５％水酸化ナトリウム水溶液１２８．４２部を添加して混合後にした。続いて目皿径１６ｍｍのミンチ機（ＲＯＹＡＬ社製１２ＶＲ－４００Ｋ）を使い、ゲル温度８０℃で疎水性物質（ｃ－１）｛ステアリン酸Ｍｇ｝０．１０部をゲルに添加しながら４回混練細断後、通気型バンド乾燥機｛１５０℃、風速２ｍ／秒｝で乾燥し、乾燥体を得た。乾燥体をジューサーミキサー（Ｏｓｔｅｒ社製ＯＳＴＥＲＩＺＥＲ　ＢＬＥＮＤＥＲ）にて粉砕した後、目開き７１０～１５０μｍの粒子径範囲に調整することにより、乾燥体粒子を得た。この時の乾燥粒子体の重量平均粒子径は３９２μｍであった。この乾燥体粒子１００部を高速攪拌しながらエチレングリコールジグリシジルエーテルの２％水／メタノール混合溶液（水／メタノールの重量比＝７０／３０）の５．００部をスプレー噴霧しながら加えて混合し、１５０℃で３０分間静置して表面架橋して、吸水性樹脂粒子（Ｐ－１）を得た。 Next, 502.27 parts of this hydrogel (1) was subdivided into about 1 mm square pieces with scissors, and 128.42 parts of 48.5% sodium hydroxide aqueous solution was added and mixed. Then, using a mincing machine (12VR-400K manufactured by ROYAL) having a perforated plate diameter of 16 mm, at a gel temperature of 80 ° C., add 0.10 parts of the hydrophobic substance (c-1) {Mg stearate} to the gel four times. After kneading and shredding, it was dried with a ventilation band dryer {150 ° C., wind speed 2 m / sec} to obtain a dried body. The dried product was crushed with a juicer mixer (OSTERIZER BLENDER manufactured by Oster Co.), and then adjusted to a particle size range of 710 to 150 μm, to obtain dried particles. The weight average particle diameter of the dried particles at this time was 392 μm. While mixing 100 parts of the dried particles with high speed, 5.00 parts of a 2% water / methanol mixed solution of ethylene glycol diglycidyl ether (water / methanol weight ratio = 70/30) was added by spraying and mixed. The mixture was allowed to stand at 150 ° C. for 30 minutes for surface cross-linking to obtain water-absorbent resin particles (P-1).
＜実施例２＞
　ゲル温度８０℃を１２０℃に変更した以外は実施例１と同様にして吸水性樹脂粒子（Ｐ－２）を得た。 <Example 2>
Water-absorbent resin particles (P-2) were obtained in the same manner as in Example 1 except that the gel temperature was changed from 80 ° C to 120 ° C.
＜実施例３＞
　ゲル温度８０℃を４０℃に変更した以外は実施例１と同様にして吸水性樹脂粒子（Ｐ－３）を得た。 <Example 3>
Water-absorbent resin particles (P-3) were obtained in the same manner as in Example 1 except that the gel temperature was changed from 80 ° C to 40 ° C.
＜実施例４＞
　乾燥粒子体の重量平均粒子径を３９２μｍから２００μｍに変更した以外は実施例１と同様にして吸水性樹脂粒子（Ｐ－４）を得た。 <Example 4>
Water-absorbent resin particles (P-4) were obtained in the same manner as in Example 1 except that the weight average particle diameter of the dried particles was changed from 392 μm to 200 μm.
＜実施例５＞
　含水ゲル（１）５０２．２７部をはさみで約１ｍｍ角に細分し、４８．５％水酸化ナトリウム水溶液１２８．４２部を添加して混合後にした。続いて目皿径１６ｍｍのミンチ機（ＲＯＹＡＬ社製１２ＶＲ－４００Ｋ）を使い、４回混練細断後、通気型バンド乾燥機｛１５０℃、風速２ｍ／秒｝で乾燥し、乾燥体を得た。乾燥体をジューサーミキサー（Ｏｓｔｅｒ社製ＯＳＴＥＲＩＺＥＲ　ＢＬＥＮＤＥＲ）にて粉砕した後、目開き７１０～１５０μｍの粒子径範囲に調整することにより、乾燥体粒子を得た。この乾燥体粒子１００部を高速攪拌しながらエチレングリコールジグリシジルエーテルの２％水／メタノール混合溶液（水／メタノールの重量比＝７０／３０）の７．３０部と疎水性物質（ｃ－２）｛カルボキシ変性ポリシロキサン　型番　Ｘ－２２－３７０１Ｅ　信越化学工業株式会社製｝０．０２部をスプレー噴霧しながら加えて混合し、１５０℃で３０分間静置して表面架橋し、複合粒子を得た。この複合粒子１００部と無機質粉末（二酸化ケイ素、トクシール、体積平均粒子経２．５μｍ、比表面積１２０ｍ２／ｇ　株式会社トクヤマ製）０．４部とをコニカルブレンダー｛ホソカワミクロン株式会社製｝で均一混合して、吸収性樹脂粒子（Ｐ－５）を得た。 <Example 5>
502.27 parts of the hydrogel (1) was subdivided into about 1 mm square with scissors, and 128.42 parts of 48.5% sodium hydroxide aqueous solution was added and mixed. Subsequently, using a mincing machine (12VR-400K manufactured by ROYAL) having a perforation diameter of 16 mm, after kneading and shredding four times, it was dried with a ventilation band dryer {150 ° C., wind speed 2 m / sec} to obtain a dried body. .. The dried product was pulverized with a juicer mixer (OSTERIZER BLENDER manufactured by Oster), and then the dried product particles were adjusted to have a particle size range of 710 to 150 μm. While stirring 100 parts of the dried particles at a high speed, 7.30 parts of a 2% water / methanol mixed solution of ethylene glycol diglycidyl ether (water / methanol weight ratio = 70/30) and a hydrophobic substance (c-2) {Carboxy-modified polysiloxane model number X-22-3701E manufactured by Shin-Etsu Chemical Co., Ltd.} 0.02 parts was added by spraying and mixing, and the mixture was allowed to stand at 150 ° C. for 30 minutes for surface cross-linking to obtain composite particles. .. 100 parts of this composite particle and 0.4 part of inorganic powder (silicon dioxide, Tokseal, volume average particle size 2.5 μm, specific surface area 120 m 2 / g made by Tokuyama Co., Ltd.) are uniformly mixed with a conical blender {made by Hosokawa Micron Co., Ltd.}. Thus, absorbent resin particles (P-5) were obtained.
＜実施例６＞
　含水ゲル（１）５０２．２７部をはさみで約１ｍｍ角に細分し、４８．５％水酸化ナトリウム水溶液１２８．４２部を添加して混合後にした。続いて目皿径１６ｍｍのミンチ機（ＲＯＹＡＬ社製１２ＶＲ－４００Ｋ）を使い、４回混練細断後、通気型バンド乾燥機｛１５０℃、風速２ｍ／秒｝で乾燥し、乾燥体を得た。乾燥体をジューサーミキサー（Ｏｓｔｅｒ社製ＯＳＴＥＲＩＺＥＲ　ＢＬＥＮＤＥＲ）にて粉砕した後、目開き７１０～１５０μｍの粒子径範囲に調整することにより、乾燥体粒子を得た。この乾燥体粒子１００部を高速攪拌しながらエチレングリコールジグリシジルエーテルの２％水／メタノール混合溶液（水／メタノールの重量比＝７０／３０）の７．３０部をスプレー噴霧しながら加えて混合し、１５０℃で３０分間静置して表面架橋し、複合粒子を得た。この複合粒子１００部、メタノール１．０部、疎水性物質（ｃ－２）０．０２部をコニカルブレンダー｛ホソカワミクロン株式会社製｝で均一混合して、吸収性樹脂粒子（Ｐ－６）を得た。 <Example 6>
502.27 parts of the hydrogel (1) was subdivided into about 1 mm square with scissors, and 128.42 parts of 48.5% sodium hydroxide aqueous solution was added and mixed. Subsequently, using a mincing machine (12VR-400K manufactured by ROYAL) having a perforation diameter of 16 mm, after kneading and shredding four times, it was dried with a ventilation band dryer {150 ° C., wind speed 2 m / sec} to obtain a dried body. .. The dried product was pulverized with a juicer mixer (OSTERIZER BLENDER manufactured by Oster), and then the dried product particles were adjusted to have a particle size range of 710 to 150 μm. While mixing 100 parts of the dried particles at a high speed, 7.30 parts of a 2% water / methanol mixed solution of ethylene glycol diglycidyl ether (water / methanol weight ratio = 70/30) was added by spraying and mixing. The mixture was allowed to stand at 150 ° C. for 30 minutes for surface cross-linking to obtain composite particles. 100 parts of the composite particles, 1.0 part of methanol, and 0.02 part of the hydrophobic substance (c-2) were uniformly mixed with a conical blender {made by Hosokawa Micron Co., Ltd.} to obtain absorbent resin particles (P-6). It was
＜実施例７＞
　無機質粉末０．４部を添加しない、に変更した以外は、実施例５と同様にして、吸水性樹脂粒子（Ｐ－７）を得た。 <Example 7>
Water-absorbent resin particles (P-7) were obtained in the same manner as in Example 5, except that 0.4 part of the inorganic powder was not added.
＜実施例８＞
　疎水性物質（ｃ－２）を０．０２部から０．０４部に変更した以外は、実施例５と同様にして、吸水性樹脂粒子（Ｐ－８）を得た。 <Example 8>
Water-absorbent resin particles (P-8) were obtained in the same manner as in Example 5, except that the amount of the hydrophobic substance (c-2) was changed from 0.02 part to 0.04 part.
＜実施例９＞
　疎水性物質（ｃ－２）を０．０２部から０．１０部に変更した以外は、実施例５と同様にして、吸水性樹脂粒子（Ｐ－９）を得た。 <Example 9>
Water-absorbent resin particles (P-9) were obtained in the same manner as in Example 5, except that the amount of the hydrophobic substance (c-2) was changed from 0.02 part to 0.10 part.
＜実施例１０＞
　疎水性物質（ｃ－１）０．１０部を疎水性物質（ｃ－３）｛ショ糖ステアリン酸モノエステル｝０．１５部に変更、４回混練を２回混練に変更した以外は、実施例１と同様にして吸水性樹脂粒子（Ｐ－１０）を得た。 <Example 10>
Implemented except that 0.10 part of the hydrophobic substance (c-1) was changed to 0.15 part of the hydrophobic substance (c-3) {sucrose stearic acid monoester} and 4 times kneading was changed to 2 times kneading. Water-absorbent resin particles (P-10) were obtained in the same manner as in Example 1.
＜実施例１１＞
　はさみで約１ｍｍ角に細分を約５ｍｍ角に細分に変更し、かつ、疎水性物質（ｃ－１）０．１０部を疎水性物質（ｃ－３）０．１５部に変更した以外は、実施例１と同様にして吸水性樹脂粒子（Ｐ－１１）を得た。 <Example 11>
Except for changing the subdivision into about 1 mm square with scissors into about 5 mm square, and changing 0.10 part of the hydrophobic substance (c-1) to 0.15 part of the hydrophobic substance (c-3), Water-absorbent resin particles (P-11) were obtained in the same manner as in Example 1.
＜実施例１２＞
　目皿径１６ｍｍを８ｍｍに変更し、かつ、疎水性物質（ｃ－１）０．１０部を疎水性物質（ｃ－３）０．１５部に変更した以外は、実施例１と同様にして吸水性樹脂粒子（Ｐ－１２）を得た。 <Example 12>
Same as Example 1 except that the diameter of the perforated plate 16 mm was changed to 8 mm, and 0.10 part of the hydrophobic substance (c-1) was changed to 0.15 part of the hydrophobic substance (c-3). Water-absorbent resin particles (P-12) were obtained.
＜比較例１＞
　疎水性物質（ｃ－１）を添加しない、に変更した以外は、実施例１と同様にして比較用の吸水性樹脂粒子（Ｈ－１）を得た。 <Comparative Example 1>
Comparative water absorbent resin particles (H-1) were obtained in the same manner as in Example 1 except that the hydrophobic substance (c-1) was not added.
＜比較例２＞　約１ｍｍ角に細分した含水ゲルをミンチ機（ＲＯＹＡＬ社製１２ＶＲ－４００Ｋ）で混練細断せずに、通気型乾燥機｛１５０℃、風速２ｍ／秒｝で乾燥し、乾燥体を得たこと以外、実施例１と同様にして比較用の吸水性樹脂粒子（Ｈ－２）を得た。 <Comparative Example 2> A hydrogel subdivided into about 1 mm square was kneaded with a mincing machine (ROYAL's 12VR-400K) without being shredded and dried with a ventilation dryer {150 ° C, wind speed 2 m / sec} and dried. Comparative water absorbing resin particles (H-2) were obtained in the same manner as in Example 1 except that the body was obtained.
＜比較例３＞　目開き７１０～１５０μｍの粒子径範囲を、目開き７１０～３００μｍの粒子径範囲に変更する以外は、実施例１と同様の操作を行い、吸水性樹脂粒子（Ｈ－３）を得た。 <Comparative Example 3> Water-absorbent resin particles (H-3) were prepared in the same manner as in Example 1, except that the particle size range of openings 710 to 150 μm was changed to the particle size range of openings 710 to 300 μm. Got
＜比較例４＞
　ゲル温度８０℃を２０℃に変更した以外は、実施例１と同様の操作を行い、吸水性樹脂粒子（Ｈ－４）を得た。 <Comparative example 4>
Water-absorbent resin particles (H-4) were obtained in the same manner as in Example 1 except that the gel temperature was changed from 80 ° C to 20 ° C.
＜比較例５＞
　乾燥温度１５０℃を３００℃に変更した以外は、実施例１と同様の操作を行い、吸水性樹脂粒子（Ｈ－５）を得た。 <Comparative Example 5>
Water-absorbent resin particles (H-5) were obtained in the same manner as in Example 1, except that the drying temperature was changed from 150 ° C to 300 ° C.
＜比較例６＞
　表面架橋温度１５０℃を９０℃に変更した以外は、実施例１と同様の操作を行い、吸水性樹脂粒子（Ｈ－６）を得た。 <Comparative example 6>
Water-absorbent resin particles (H-6) were obtained in the same manner as in Example 1, except that the surface crosslinking temperature of 150 ° C was changed to 90 ° C.
＜比較例７＞
　表面架橋温度１５０℃を２１０℃に変更した以外は、実施例１と同様の操作を行い、吸水性樹脂粒子（Ｈ－７）を得た。 <Comparative Example 7>
Water-absorbent resin particles (H-7) were obtained in the same manner as in Example 1, except that the surface crosslinking temperature of 150 ° C was changed to 210 ° C.
＜比較例８＞　市販品のおむつＧＯＯ．Ｎ（パンツＬサイズ　大王製紙(株)社製、２０１８年５月　日本）を手で解砕し、吸収体に含まれている破砕状の吸水性樹脂粒子をパルプと共に取出し後にそれぞれを分別し、破砕状の吸水性樹脂粒子（Ｈ－８）を得た。 <Comparative Example 8> Commercially available diaper GOO. N (pants L size, manufactured by Daio Paper Co., Ltd., May 2018, Japan) was manually crushed, and the crushed water-absorbent resin particles contained in the absorber were taken out together with the pulp, and then each was separated, Crushed water-absorbent resin particles (H-8) were obtained.
＜比較例９＞
　市販品のおむつＧＯＯ．Ｎ（パンツＳサイズ　大王製紙(株)社製、２０１８年５月　日本）を手で解砕し、吸収体に含まれている球形状の吸水性樹脂粒子をパルプと共に取出し後にそれぞれを分別し、真球状の吸水性樹脂粒子（Ｈ－９）を得た。 <Comparative Example 9>
Commercially available diaper GOO. N (pants S size manufactured by Daio Paper Co., Ltd., May 2018, Japan) was crushed by hand, and the spherical water-absorbent resin particles contained in the absorber were taken out together with the pulp, and then each was separated, True spherical water-absorbent resin particles (H-9) were obtained.
＜衛生用品の調製＞
　親水性繊維（フラッフパルプ）１００部と吸水性樹脂粒子（実施例及び比較例で得られた各吸水性樹脂粒子）１００部とを気流型混合装置（パッドフォーマー）で混合して、混合物を得た後、この混合物を目付５００ｇ／ｍ２となるように均一にアクリル板（厚み４ｍｍ）上に積層し、５ｋｇ／ｃｍ２の圧力で３０秒間プレスし、吸収体を得た。この吸収体を１０ｃｍ×１０ｃｍの正方形に裁断し、各々の上下に吸収体と同じ大きさの透水性シート（目付け１５．５ｇ／ｍ２、アドバンテック社製、フィルターペーパー２番）を配置し、更に不透過性シートとしてポリエチレンシート（Ｓ－１）（タマポリ社製ポリエチレンフィルムＵＢ－１）を裏面に、不織布層として不織布（Ｓ－２）を表面に配置することにより、衛生用品を調製した。 <Preparation of hygiene products>
100 parts of hydrophilic fibers (fluff pulp) and 100 parts of water-absorbent resin particles (water-absorbent resin particles obtained in Examples and Comparative Examples) were mixed by an air flow type mixing device (pad former) to form a mixture. After this was obtained, this mixture was uniformly laminated on an acrylic plate (thickness: 4 mm) so that the basis weight was 500 g / m 2, and pressed at a pressure of 5 kg / cm 2 for 30 seconds to obtain an absorber. This absorbent body was cut into 10 cm × 10 cm squares, and a water-permeable sheet (unit weight: 15.5 g / m 2 , Advantech, filter paper No. 2) of the same size as the absorbent body was arranged above and below each, and further. A hygiene article was prepared by disposing a polyethylene sheet (S-1) (polyethylene film UB-1 manufactured by Tama Poly Co., Ltd.) as an impermeable sheet on the back surface and a nonwoven fabric (S-2) as a nonwoven fabric layer on the front surface.
＜吸収体の脱水性評価＞
　調製した衛生用品を、不織布（Ｓ－２）側が上面になるように金属性のバット上に置き、３００ｍｌビーカーに入れた生理食塩水（食塩濃度０．９％）１５０ｍｌを衛生用品に均一的になるように静かに注ぎ入れて、２０分間静置した後、不織布（Ｓ－１）及び（Ｓ－２）を衛生用品から取り除き、膨潤した吸収体の重量（ｈ５；ｇ）を測定した。次いで、目開き６３μｍ（ＪＩＳ　Ｚ８８０１－１：２００６）のナイロン網で作製したティーバッグ（縦１５ｃｍ、横１５ｃｍ）に膨潤した吸収体を入れて、１．０重量％塩化カルシウム水溶液１，０００ｍｌ中に無撹拌下、５分間浸漬した後引き上げて、遠心分離器にいれ、１５０Ｇで９０秒間遠心脱水して余剰の塩化カルシウム水溶液を取り除き、ティーバッグを含めた重量（ｈ６；ｇ）を測定し下式から吸収体脱水率を求める。なお、使用した生理食塩水、塩化カルシウム水溶液及び測定雰囲気の温度は２５℃±２℃とする。（ｈ７；ｇ）は、同様に吸収体を作製し、５時間静置した後、不織布（Ｓ－１）及び（Ｓ－２）を衛生用品から取り除き、膨潤した吸収体の重量（ｈ７；ｇ）を測定した場合の重量である。
　吸収体脱水率（％）＝[１－｛（ｈ６）－（ｈ７）｝／（ｈ５）]×１００ <Evaluation of dehydration property of absorber>
Place the prepared hygiene product on a metal vat with the non-woven fabric (S-2) side facing up, and uniformly add 150 ml of physiological saline (saline concentration 0.9%) in a 300 ml beaker to the hygiene product. After gently pouring the mixture in such a manner that it was left still for 20 minutes, the nonwoven fabrics (S-1) and (S-2) were removed from the hygiene article, and the weight (h5; g) of the swollen absorbent body was measured. Then, the swollen absorber was placed in a tea bag (15 cm in length, 15 cm in width) made of a nylon net having an opening of 63 μm (JIS Z8801-1: 2006), and the tea bag was placed in 1,000 ml of a 1.0 wt% calcium chloride aqueous solution. After soaking without stirring for 5 minutes, pull up, put in a centrifuge, spin-dry for 90 seconds at 150 G to remove excess calcium chloride aqueous solution, and measure the weight including the tea bag (h6; g) The dehydration rate of the absorber is calculated from The temperatures of the physiological saline solution, the calcium chloride aqueous solution and the measurement atmosphere used are 25 ° C. ± 2 ° C. (H7; g) is the weight of the absorbent (h7; g) swollen after the absorbent was prepared in the same manner and allowed to stand for 5 hours, then the nonwoven fabrics (S-1) and (S-2) were removed from the hygiene article. ) Is the weight when measured.
Absorber dehydration rate (%) = [1-{(h6)-(h7)} / (h5)] × 100
　実施例及び比較例で得た吸水性樹脂について、生理食塩水に対する保水量、荷重下吸収量、生理食塩水のゲル通液速度、見かけ密度、重量平均粒子径、１．０重量％塩化カルシウム水溶液のゲル通液速度、離水率、イオン交換水による再膨潤倍率の結果を表１、２に示した。また、各吸水性樹脂を使用して調整した吸収体の脱水性評価結果も併せて示す。 Regarding the water-absorbent resins obtained in Examples and Comparative Examples, water retention capacity against physiological saline, absorption under load, gel permeation rate of physiological saline, apparent density, weight average particle size, 1.0 wt% calcium chloride aqueous solution The results of gel passing rate, water separation rate, and re-swelling ratio with ion-exchanged water are shown in Tables 1 and 2. In addition, the results of evaluation of the dehydration property of the absorbent body prepared by using each water absorbent resin are also shown.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000002
　表１、２に示す結果から明らかなように、本発明の脱水処理が容易な吸水性樹脂粒子は、比較例の吸水性樹脂粒子と比べて、離水率が向上している。また、本吸水性樹脂粒子を使用した吸収体の離水率評価において、吸水性樹脂粒子の離水率が高いほど吸収体の離水率向上に寄与することが分かる。本結果は、離水率が高い吸水性樹脂粒子を使用した吸収体は、膨潤した吸収体の脱水処理後の含水量が下がり、吸収体1枚当たりの総重量を低減することができると言える。そのため、例えば、排尿後に塩化カルシウム水溶液で同様の処理操作をすることで、運搬時の労力が軽減できることや、焼却処理する際に、焼却に利用するエネルギーを抑制できるため環境負荷を低減できる。 As is clear from the results shown in Tables 1 and 2, the water-absorbent resin particles of the present invention which can be easily dehydrated have an improved water separation rate as compared with the water-absorbent resin particles of Comparative Example. Further, in the evaluation of the water separation rate of the absorbent body using the present water-absorbent resin particles, it is found that the higher the water separation rate of the water-absorbent resin particles, the higher the water separation rate of the absorbent body. This result indicates that the absorbent body using the water absorbent resin particles having a high water separation rate has a reduced water content after the dehydration treatment of the swollen absorbent body, and can reduce the total weight per absorbent body. Therefore, for example, by performing the same treatment operation with an aqueous solution of calcium chloride after urination, the labor during transportation can be reduced, and the energy used for incineration at the time of incineration treatment can be suppressed, so that the environmental load can be reduced.
　本発明の脱水処理が容易な吸水性樹脂粒子を衛生用品を含む各種吸収性物品に適用することにより、使用時には必要な吸収性能を満たしながら、使用後には所定の脱水処理により、吸収性物品の含水率を容易に低下させることができることから、紙おむつ（子供用紙おむつ及び大人用紙おむつ等）、ナプキン（生理用ナプキン等）、紙タオル、パッド（失禁者用パッド及び手術用アンダーパッド等）及びペットシート（ペット尿吸収シート）等の衛生用品に好適に用いられ、特に紙おむつに最適である。 By applying the water-absorbent resin particles of the present invention that are easily dehydrated to various absorbent articles including hygiene products, while satisfying the necessary absorption performance during use, after a predetermined dehydration treatment after use, the absorbent article Since the water content can be easily reduced, disposable diapers (children's paper diapers and adult paper diapers, etc.), napkins (sanitary napkins, etc.), paper towels, pads (incontinence pads, surgical underpads, etc.), and pets It is suitable for use in hygiene products such as sheets (pet urine absorption sheets), and is most suitable for disposable diapers.
１　生理食塩水
２　含水ゲル粒子
３　円筒
４　底部から６０ｍｌの位置の目盛り線
５　底部から４０ｍｌの位置の目盛り線
６　金網
７　コック
８　円形金網
９　加圧軸
１０　おもり 1 physiological saline solution 2 hydrogel particles 3 cylinder 4 scale line at a position 60 ml from the bottom 5 scale line at a position 40 ml from the bottom 6 wire net 7 cock 8 circular wire net 9 pressure shaft 10 weight

Claims (20)

  1. 　水溶性ビニルモノマー（ａ１）及び／又は加水分解により水溶性ビニルモノマー（ａ１）となるビニルモノマー（ａ２）並びに内部架橋剤（ｂ）を必須構成単位とする架橋重合体（Ａ）を含有し、下記式（１）で示される離水率が７０％以上である、脱水処理が容易な吸水性樹脂粒子。
    　離水率［％］＝｛１－（１．０重量％塩化カルシウム水溶液処理後の保水量［ｇ／ｇ］）／（生理食塩水に対する保水量［ｇ／ｇ］）｝×１００　　　　（１）     A water-soluble vinyl monomer (a1) and / or a vinyl monomer (a2) which becomes a water-soluble vinyl monomer (a1) by hydrolysis and a cross-linked polymer (A) containing an internal cross-linking agent (b) as an essential constituent unit, Water-absorbent resin particles having a water separation rate represented by the following formula (1) of 70% or more and which can be easily dehydrated.
    Water separation rate [%] = {1- (water retention amount after treatment with 1.0 wt% calcium chloride aqueous solution [g / g]) / (water retention amount against physiological saline [g / g])} × 100 (1)
  2. 　前記離水率が７５％以上である請求項１に記載の吸水性樹脂粒子。 The water absorbent resin particles according to claim 1, wherein the water separation ratio is 75% or more.
  3. 　下記式（２）で示されるイオン交換水による再膨潤倍率が１１０％以下である請求項１又は２に記載の吸水性樹脂粒子。
    　イオン交換水による再膨潤倍率［％］＝（１．０重量％塩化カルシウム水溶液処理後のイオン交換水に対する保水量［ｇ／ｇ］）／（生理食塩水に対する保水量［ｇ／ｇ］）×１００　（２）     The water-absorbent resin particle according to claim 1 or 2, which has a re-swelling ratio of 110% or less with ion-exchanged water represented by the following formula (2).
    Re-swelling ratio with ion-exchanged water [%] = (water retention amount [g / g] for ion-exchanged water after treatment with 1.0 wt% calcium chloride aqueous solution) / (water retention amount for physiological saline [g / g]) × 100 (2)
  4. 　１．０重量％塩化カルシウム水溶液のゲル通液速度が２００ｍｌ／分以上である請求項１～３のいずれかに記載の吸水性樹脂粒子。 4. The water-absorbent resin particles according to any one of claims 1 to 3, wherein the 1.0 wt% calcium chloride aqueous solution has a gel flow rate of 200 ml / min or more.
  5. 　前記吸水性樹脂粒子が長鎖脂肪酸エステル、長鎖脂肪酸及びその塩、長鎖脂肪族アルコール並びに長鎖脂肪族アミド、カルボキシ変性ポリシロキサン、エポキシ変性ポリシロキサン、アミノ変性ポリシロキサン並びにアルコキシ変性ポリシロキサンからなる群から選ばれる少なくとも１種の疎水性物質（ｃ）を含有している請求項１～４のいずれかに記載の吸水性樹脂粒子。 The water-absorbent resin particles are composed of long-chain fatty acid ester, long-chain fatty acid and its salt, long-chain aliphatic alcohol and long-chain aliphatic amide, carboxy-modified polysiloxane, epoxy-modified polysiloxane, amino-modified polysiloxane and alkoxy-modified polysiloxane. The water absorbent resin particles according to any one of claims 1 to 4, containing at least one kind of hydrophobic substance (c) selected from the group consisting of:
  6. 　生理食塩水に対する保水量が３０～５０ｇ／ｇである請求項１～５のいずれかに記載の吸水性樹脂粒子。 The water-absorbent resin particles according to any one of claims 1 to 5, which has a water retention capacity of 30 to 50 g / g with respect to physiological saline.
  7. 　見かけ密度が０．４０～０．６２ｇ／ｍｌである請求項１～６のいずれかに記載の吸水性樹脂粒子。 The water absorbent resin particles according to any one of claims 1 to 6, which has an apparent density of 0.40 to 0.62 g / ml.
  8. 　重量平均粒子径が１５０～５００μｍである請求項１～７のいずれかに記載の吸水性樹脂粒子。 The water absorbent resin particles according to any one of claims 1 to 7, which have a weight average particle diameter of 150 to 500 µm.
  9. 　粒子形状が不定形破砕状である請求項１～７のいずれかに記載の吸水性樹脂粒子。 The water-absorbent resin particle according to any one of claims 1 to 7, wherein the particle shape is an irregular crushed shape.
  10. 　請求項１～９のいずれかに１項に記載の吸水性樹脂粒子の製造方法であって、水溶性ビニルモノマー（ａ１）及び／又は加水分解により水溶性ビニルモノマー（ａ１）となるビニルモノマー（ａ２）並びに内部架橋剤（ｂ）を必須構成単位とする単量体組成物を重合して、架橋重合体（Ａ）を含有する含水ゲルを得る重合工程、架橋重合体（Ａ）の含水ゲルを細分する工程、細分した含水ゲルをゲル温度４０℃～１２０℃でさらに混練細断する工程、及び前記混練細断した含水ゲルを乾燥した後に粉砕して、吸水性樹脂粒子を得る工程を含む、前記吸水性樹脂粒子の製造方法。 The method for producing water-absorbent resin particles according to any one of claims 1 to 9, wherein the water-soluble vinyl monomer (a1) and / or a vinyl monomer that becomes a water-soluble vinyl monomer (a1) by hydrolysis ( a2) and a polymerization step of polymerizing a monomer composition containing the internal crosslinking agent (b) as an essential constituent unit to obtain a hydrogel containing the crosslinked polymer (A), a hydrogel of the crosslinked polymer (A) And a step of further kneading the finely divided hydrogel at a gel temperature of 40 ° C. to 120 ° C., and a step of drying the finely kneaded hydrogel and then pulverizing to obtain water-absorbent resin particles. A method for producing the water-absorbent resin particles.
  11. 　表面架橋工程を有する請求項１０に記載の製造方法。 The manufacturing method according to claim 10, which has a surface cross-linking step.
  12. 　表面架橋工程後に粒度調整する工程を有する請求項１１に記載の製造方法。 The manufacturing method according to claim 11, which has a step of adjusting the particle size after the surface crosslinking step.
  13. 　請求項１～９のいずれか１項に記載の吸水性樹脂粒子を含み、使用済品からの水分の脱水処理が容易な衛生用品。 Hygiene products containing the water-absorbent resin particles according to any one of claims 1 to 9 and capable of easily dehydrating water from used products.
  14. 　請求項１３に記載の衛生用品の使用済品の処理方法であって、使用済みとなった衛生用品を粉砕する工程と、衛生用品又は粉砕された衛生用品に含まれる吸水性樹脂粒子を脱水剤により脱水処理する工程、粉砕及び脱水処理された衛生用品を水と混合して固液処理装置に輸送する工程を含む衛生用品の処理方法。 The method for treating a used hygiene article according to claim 13, wherein the step of crushing the used hygiene article and the water absorbent resin particles contained in the hygiene article or the crushed hygiene article are dehydrated. A method for treating hygiene products, comprising the steps of dehydration treatment by means of water, and the step of mixing the pulverized and dehydrated hygiene products with water and transporting them to a solid-liquid treatment device.
  15. 　脱水剤がマグネシウムを含む水溶性多価金属化合物及び／又はカルシウムを含む水溶性多価金属化合物である請求項１４に記載の衛生用品の処理方法。 The method for treating hygiene products according to claim 14, wherein the dehydrating agent is a water-soluble polyvalent metal compound containing magnesium and / or a water-soluble polyvalent metal compound containing calcium.
  16. 　脱水剤が塩化カルシウム、酸化カルシウム、酢酸カルシウム、及び次亜塩素酸カルシウムからなる群より選ばれる少なくとも１種の水溶性多価金属化合物である請求項１４又は１５に記載の衛生用品の処理方法。 The method for treating hygiene products according to claim 14 or 15, wherein the dehydrating agent is at least one water-soluble polyvalent metal compound selected from the group consisting of calcium chloride, calcium oxide, calcium acetate, and calcium hypochlorite.
  17. 　衛生用品を粉砕する工程と衛生用品又は粉砕された衛生用品に含まれる吸水性樹脂粒子を脱水剤により脱水処理する工程を順次又は同時に実施する請求項１４～１６のいずれか１項に記載の処理方法。 The treatment according to any one of claims 14 to 16, wherein the step of pulverizing the sanitary article and the step of dehydrating the water-absorbent resin particles contained in the hygiene article or the pulverized hygiene article with a dehydrating agent are performed sequentially or simultaneously. Method.
  18. 　粉砕及び脱水処理された衛生用品が配管又はホースを経由して、水流で固液処理装置に輸送される請求項1４～１７のいずれか１項に記載の処理方法。 The treatment method according to any one of claims 14 to 17, wherein the crushed and dehydrated sanitary ware is transported to the solid-liquid treatment device by a water flow via a pipe or a hose.
  19. 　衛生用品がパルプ繊維及び吸水性樹脂粒子を含む衛生用品である請求項１４～１８のいずれか１項に記載の処理方法。 The treatment method according to any one of claims 14 to 18, wherein the hygiene article is a hygiene article containing pulp fibers and water-absorbent resin particles.
  20. 　使用済み衛生用品を請求項１４～１９のいずれかに記載の処理方法で処理する、固形燃料の製造方法。 A method for producing a solid fuel, in which used hygiene products are treated by the treatment method according to any one of claims 14 to 19.
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