WO2020105277A1 - Particules de résine absorbant l'eau facilement déshydratables et leur procédé de production - Google Patents

Particules de résine absorbant l'eau facilement déshydratables et leur procédé de production

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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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Prior art keywords
water
absorbent resin
resin particles
vinyl monomer
acid
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PCT/JP2019/037462
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English (en)
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/zh
Publication of WO2020105277A1 publication Critical patent/WO2020105277A1/fr

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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.

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  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Health & Medical Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Medicinal Chemistry (AREA)
  • Polymers & Plastics (AREA)
  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Materials Engineering (AREA)
  • Oil, Petroleum & Natural Gas (AREA)
  • Absorbent Articles And Supports Therefor (AREA)
  • Addition Polymer Or Copolymer, Post-Treatments, Or Chemical Modifications (AREA)

Abstract

La présente invention concerne des particules de résine absorbant l'eau qui présentent d'excellentes caractéristiques d'absorption de l'eau en utilisation normale et qui sont facilement déshydratables après utilisation ; un procédé de production de celles-ci ; et un procédé de traitement d'un article d'hygiène. La présente invention concerne des particules de résine absorbant l'eau, un article d'hygiène les comprenant, et un procédé de traitement de l'article d'hygiène, les particules de résine absorbant l'eau contenant un polymère réticulé (A) ayant, en tant que motifs constitutifs essentiels : un monomère de vinyle soluble dans l'eau (a1) et/ou un monomère de vinyle (a2) qui devient par hydrolyse le monomère de vinyle soluble dans l'eau (a1) ; et un agent de réticulation interne (b), le rapport de séparation aqueuse représenté par l'équation suivante étant de 70 % ou plus. Rapport de séparation aqueuse [%] = {1-(quantité de rétention d'eau après traitement avec 1,0 % en poids de solution aqueuse de chlorure de calcium [g/g])/(quantité de rétention d'eau par rapport au sérum physiologique [g/g])}×100
PCT/JP2019/037462 2018-11-21 2019-09-25 Particules de résine absorbant l'eau facilement déshydratables et leur procédé de production WO2020105277A1 (fr)

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