WO2014021388A1 - Absorbant d'eau utilisant une résine en poudre absorbant l'eau à base d'un (sel d')acide polyacrylique et procédé de fabrication d'un absorbant d'eau - Google Patents

Absorbant d'eau utilisant une résine en poudre absorbant l'eau à base d'un (sel d')acide polyacrylique et procédé de fabrication d'un absorbant d'eau Download PDF

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WO2014021388A1
WO2014021388A1 PCT/JP2013/070776 JP2013070776W WO2014021388A1 WO 2014021388 A1 WO2014021388 A1 WO 2014021388A1 JP 2013070776 W JP2013070776 W JP 2013070776W WO 2014021388 A1 WO2014021388 A1 WO 2014021388A1
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water
weight
crosslinking agent
agent
glycidyl
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PCT/JP2013/070776
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English (en)
Japanese (ja)
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博之 池内
克之 和田
中嶋　康久
舞 佐藤
邦彦 石▲崎▼
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株式会社日本触媒
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Priority to JP2014528200A priority Critical patent/JPWO2014021388A1/ja
Publication of WO2014021388A1 publication Critical patent/WO2014021388A1/fr

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J20/00—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof
    • B01J20/22—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof comprising organic material
    • B01J20/26—Synthetic macromolecular compounds
    • B01J20/265—Synthetic macromolecular compounds modified or post-treated polymers
    • B01J20/267—Cross-linked polymers
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61L—METHODS OR APPARATUS FOR STERILISING MATERIALS OR OBJECTS IN GENERAL; DISINFECTION, STERILISATION OR DEODORISATION OF AIR; CHEMICAL ASPECTS OF BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES; MATERIALS FOR BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES
    • A61L15/00—Chemical aspects of, or use of materials for, bandages, dressings or absorbent pads
    • A61L15/16—Bandages, dressings or absorbent pads for physiological fluids such as urine or blood, e.g. sanitary towels, tampons
    • A61L15/22—Bandages, dressings or absorbent pads for physiological fluids such as urine or blood, e.g. sanitary towels, tampons containing macromolecular materials
    • A61L15/24—Macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds; Derivatives thereof
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61L—METHODS OR APPARATUS FOR STERILISING MATERIALS OR OBJECTS IN GENERAL; DISINFECTION, STERILISATION OR DEODORISATION OF AIR; CHEMICAL ASPECTS OF BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES; MATERIALS FOR BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES
    • A61L15/00—Chemical aspects of, or use of materials for, bandages, dressings or absorbent pads
    • A61L15/16—Bandages, dressings or absorbent pads for physiological fluids such as urine or blood, e.g. sanitary towels, tampons
    • A61L15/42—Use of materials characterised by their function or physical properties
    • A61L15/60—Liquid-swellable gel-forming materials, e.g. super-absorbents
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J20/00—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof
    • B01J20/28—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof characterised by their form or physical properties
    • B01J20/28002—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof characterised by their form or physical properties characterised by their physical properties
    • B01J20/28004—Sorbent size or size distribution, e.g. particle size
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J20/00—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof
    • B01J20/28—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof characterised by their form or physical properties
    • B01J20/28002—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof characterised by their form or physical properties characterised by their physical properties
    • B01J20/28011—Other properties, e.g. density, crush strength
    • 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
    • C08J3/24—Crosslinking, e.g. vulcanising, of macromolecules
    • C08J3/245—Differential crosslinking of one polymer with one crosslinking type, e.g. surface crosslinking
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J2220/00—Aspects relating to sorbent materials
    • B01J2220/50—Aspects relating to the use of sorbent or filter aid materials
    • B01J2220/68—Superabsorbents
    • 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
    • C08J2333/04—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 esters
    • C08J2333/06—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 esters of esters containing only carbon, hydrogen, and oxygen, the oxygen atom being present only as part of the carboxyl radical
    • C08J2333/08—Homopolymers or copolymers of acrylic acid esters

Definitions

  • the present invention relates to a water-absorbing agent using polyacrylic acid (salt) -based water-absorbing resin powder and a method for producing the same. More specifically, a polyacrylic acid (salt) water-absorbent resin powder (water absorbent) having high physical properties with little residual raw material (particularly surface cross-linking agent and its by-products) and excellent blocking resistance during moisture absorption, and The present invention relates to a stable continuous production method.
  • Non-patent Document 1 A method for producing a water-absorbent resin including such steps is disclosed in Patent Documents 1 to 14 and the like.
  • Water-absorbent resin has many standardized physical properties (for example, water absorption ratio, water absorption capacity under pressure, water absorption speed, liquid permeability, gel stability, depending on the intended use (for example, paper diapers, sanitary napkins, etc.) Etc.) and are controlled to be produced.
  • an additive selected from the group consisting of a saturated inorganic acid and an organic acid whose surface crosslinking agent is an epoxy compound is added.
  • Patent Document 15 a method in which a surface cross-linking agent is an epoxy compound and a nucleophile such as water is added or washed under specific conditions
  • Patent Document 16 a method of treating with a polyamino acid (salt)
  • Patent Document 17 a surface cross-linking agent is a cross-linking agent selected from a polyhydric alcohol, an alkylene carbonate, an oxazolidinone compound, and a (polyvalent) oxetane compound, and at the same time as cooling the water-absorbent resin powder after heat treatment in an air stream ,
  • Patent Document 18 A method of removing at least a part of the remaining surface cross-linking agent of the water-absorbent resin powder by air flow
  • the surface cross-linking agent is amino alcohol, alcohol
  • Patent Documents 20 and 21 an improved method for surface cross-linking with alkylene carbonate (particularly ethylene carbonate), specifically, the surface cross-linking agent ethylene.
  • alkylene carbonate particularly ethylene carbonate
  • ethylene specifically, the surface cross-linking agent ethylene
  • Patent Documents 15 to 19 are effective only for a specific surface cross-linking agent, or a specific agent other than the cross-linking agent must be used for the surface cross-linking treatment, or under a stream of specific conditions. In particular, there is no effective method for reducing the epoxy compound.
  • an object of the present invention is a water absorbent suitable for use in thin sanitary materials and absorbent articles having a reduced water content and a reduced amount of residual epoxy compounds (particularly glycidyl-based crosslinking agents).
  • the present invention is to provide a highly safe water-absorbing agent having excellent physical properties such as magnification and water absorption under pressure, and a method for producing the same.
  • the present inventors in a method for producing a particulate water-absorbing agent that is surface-crosslinked with a glycidyl-based cross-linking agent, have a particle content of a particle size of 150 ⁇ m or more and less than 850 ⁇ m in the water-absorbent resin powder of 95 weight %, And combined with an organic surface cross-linking agent that is solid at room temperature (excluding glycidyl-based cross-linking agents) solves the above problems and has high physical properties and a low residual epoxy compound (glycidyl-based cross-linking agent). It was found that (water absorbing agent) can be stably obtained with high productivity, and the present invention was completed. Furthermore, the inventors have found that such a method can stably provide a water-absorbing resin (water-absorbing agent) excellent in balance such as water absorption capacity (CRC) and absorption capacity under pressure (AAP), and the present invention has been completed.
  • a water-absorbing resin water-absorbing agent
  • CRC water absorption capacity
  • the present invention relates to a method for producing a particulate water-absorbing agent in which a polyacrylic acid (salt) -based water-absorbing resin powder is surface-crosslinked with a glycidyl-based crosslinking agent, and the particle diameter in the water-absorbing resin powder is 150 ⁇ m.
  • a production method characterized in that the content of particles having a particle size of less than 850 ⁇ m is 95% by weight or more, and an organic surface cross-linking agent (excluding glycidyl-based cross-linking agent) that is solid at room temperature (excluding glycidyl-based cross-linking agent) is used in combination. .
  • the present invention provides a water-absorbing agent obtained by surface-crosslinking a polyacrylic acid (salt) -based water-absorbing resin powder with a glycidyl-based crosslinking agent, and has a particle content of 150 ⁇ m or more and less than 850 ⁇ m.
  • a particulate water-absorbing agent having a residual glycidyl-based crosslinking agent of 0 to 5 ppm or less and a moisture absorption blocking rate of 0 to 20% or less at 95% by weight or more.
  • the amount of residual epoxy compound with respect to the water-absorbent resin powder can be reduced to a range of 0 to 5 ppm.
  • a water-absorbing resin having an excellent balance of absorption capacity (CRC) and absorption capacity under pressure (AAP) can be stably provided.
  • the present invention is not limited to the following embodiments, and various modifications are possible within the scope of the claims, and technical means disclosed in different embodiments are appropriately combined. Embodiments obtained in this manner are also included in the technical scope of the present invention.
  • Patent Document 20 PCT / JP2012 / 042043
  • Patent Document 21 PCT / JP2012 / 042044
  • water absorbing agent and “moisture absorption blocking rate” not described in Patent Documents 20 and 21 are defined below.
  • water-absorbing agent refers to a gelling agent for an aqueous liquid obtained by subjecting a water-absorbing resin powder to a surface cross-linking step and, if necessary, a liquid flow improving agent adding step.
  • chelating agents, reducing agents, antioxidants, anti-coloring agents, and the like are added in an amount of 0 to 10% by mass, more preferably 0.001 to You may contain by 1 mass%.
  • the solid-state crosslinking agent at room temperature refers to a non-polymeric organic crosslinking agent having a melting point of 25 ° C. or more, and the melting point of the crosslinking agent is preferably 28 ° C. or more, more preferably 31 ° C. or more, and 33 ° C. The above is more preferable, and 35 ° C. or higher is particularly preferable.
  • “normal temperature” is defined as a range of 20 ° C. ⁇ 15 ° C. (5-35 ° C.) according to Japanese Industrial Standards (JIS Z 8703: 1983). In the microbiology, the room temperature is about 25 ° C., but in the present invention, it is within the above melting point range. A preferable melting point will be described later.
  • liquid at normal temperature refers to an organic surface crosslinking agent having a melting point of less than 25 ° C., and the melting point is preferably 0 ° C. or less, more preferably ⁇ 10 ° C. or less. A temperature of ⁇ 15 ° C. or lower is more preferable.
  • (1-4) Melting point difference Melting point difference between the above-mentioned “solid compound at normal temperature” and “liquid compound at normal temperature”. Essentially, it exceeds 0 ° C., preferably 10 ° C. or higher, preferably 20 ° C. or higher, 30 ° C. or higher. 40 ° C. or higher, 50 ° C. or higher, and 60 ° C. or higher in order.
  • the upper limit of the melting point difference between the “compound that is solid at normal temperature” and the “compound that is liquid at normal temperature” is not particularly limited, but is usually 300 ° C. or less, and preferably 200 ° C. or less.
  • Glycidyl crosslinking agent (epoxy crosslinking agent)
  • the glycidyl-based crosslinking agent is a crosslinking agent having one or more epoxy groups, preferably glycidyl groups, among a plurality of functional groups.
  • the epoxy group that is one of a plurality of functional groups include glycidol having a hydroxyl group as another functional group.
  • the crosslinking agent which has two or more epoxy groups (glycidyl group) is called a polyepoxy crosslinking agent (polyglycidyl type crosslinking agent).
  • crosslinking agents (glycidyl crosslinking agent and crosslinking agent solid at room temperature) Means a form in which the water-absorbent resin powder is cross-linked with a plurality of different cross-linking agents (particularly glycidyl cross-linking agents and organic cross-linking agents that are solid at normal temperature, optionally organic cross-linking agents that are liquid at normal temperature, and even inorganic ionic cross-linking agents) is doing. Regardless of the order of cross-linking, a plurality of different cross-linking agents may be reacted after mixing with the water-absorbent resin powder, or another cross-linking agent may be reacted after mixing with the water-absorbent resin powder. Any form in which the powder is reacted after mixing is included in the “combination of crosslinking agents”.
  • Hygroscopic blocking rate “Hygroscopic fluidity” in the present invention is an evaluation of fluidity as blocking, caking, or powder when the particulate water-absorbing agent is allowed to stand at a temperature of 25 ° C. and a relative humidity of 90% RH. Yes, determined by “moisture absorption blocking rate”.
  • X to Y indicating a range means “X or more and Y or less”.
  • t (ton) as a unit of weight means “Metric ton” (metric ton)
  • ppm means “weight ppm” unless otherwise noted.
  • weight and “mass”, “wt%” and “mass%”, “part by weight” and “part by mass” are treated as synonyms.
  • ⁇ acid (salt) means “ ⁇ acid and / or salt thereof”
  • (meth) acryl means “acryl and / or methacryl”.
  • the present invention relates to a method for producing a particulate water-absorbing agent in which polyacrylic acid (salt) -based water-absorbing resin powder is surface-crosslinked with a glycidyl-based cross-linking agent, and the particle content in the water-absorbing resin powder is 150 ⁇ m or more and less than 850 ⁇ m. It is a production method in which an organic surface cross-linking agent (except for a glycidyl-based cross-linking agent) that is 95% by weight or more and is solid at normal temperature is used in combination.
  • the production method of the polyacrylic acid (salt) water-absorbing resin powder used is not particularly limited, and a known production method can be applied.
  • a known production method can be applied.
  • [2] Polyacrylic acid (Patent Documents 20 and 21) The production method (general) of the salt) -based water-absorbent resin powder can be applied, and the description in this paragraph is the description of the present application as it is.
  • acrylic acid (salt) monomer aqueous solution means an acrylic acid (salt) monomer as a main component.
  • a monomer which is prepared with components constituting the water-absorbent resin powder such as a crosslinking agent, a graft component and a trace component (a chelating agent, a surfactant, a dispersing agent, etc.) if necessary.
  • the polymerization initiator is added as it is to be subjected to polymerization.
  • the acrylic acid (salt) used in the acrylic acid (salt) monomer aqueous solution may be unneutralized or salt type (completely neutralized type or partially neutralized type).
  • the acrylic acid (salt) monomer aqueous solution is not only an aqueous solution in which all solute components are completely dissolved, but also an aqueous dispersion and / or a solute component in which some solute components are dispersed without being dissolved.
  • the state of the aqueous dispersion in which the part is not dissolved is also included.
  • at least the concentration of acrylic acid (salt) is not more than a saturated concentration.
  • the solvent of the monomer aqueous solution is preferably water as a main component.
  • the main component of the solvent is water” means that 100% by weight of the solvent is not limited to water, and a water-soluble organic solvent (for example, alcohol) is 0 to 30% by weight, preferably 0 to 5%. In the present invention, these are treated as an aqueous solution.
  • the acrylic acid (salt) monomer of the present invention is not particularly limited as long as it becomes a water absorbent resin (water absorbent resin powder) by polymerization.
  • the content (amount of use) of the acrylic acid (salt) monomer is usually 50 mol% or more, preferably 70 mol% or more, more preferably based on the whole monomer (excluding the internal crosslinking agent). Is 80 mol% or more, more preferably 90 mol% or more, particularly preferably 95 mol% or more (the upper limit is 100 mol%).
  • polyacrylic acid is not limited to non-neutralization (neutralization rate of 0 mol%), but is a concept including partial neutralization or complete neutralization (neutralization rate of 100 mol%).
  • the neutralization rate of the acrylic acid (salt) monomer or the hydrogel crosslinked polymer after polymerization is not particularly limited, but the properties of the resulting water-absorbent resin powder and the reactivity of the surface crosslinking agent are not limited. From the viewpoint, 40 to 90 mol% is preferable, 50 to 80 mol% is more preferable, and 60 to 74 mol% is still more preferable.
  • the neutralization may be performed in advance with a monomer, may be performed after polymerization, or neutralization of a monomer and a polymer may be used in combination.
  • the neutralization rate When the neutralization rate is low, the water absorption rate (for example, FSR) tends to decrease. Conversely, when the neutralization rate is high, polyacrylic acid (salt) water-absorbing resin powder and a surface cross-linking agent, particularly those described later. Since the reactivity with the dehydration-reactive surface cross-linking agent and further with the alkylene carbonate decreases, the productivity and the water absorption capacity under pressure (for example, AAP) tend to decrease, so the neutralization rate within the above range is preferable. .
  • acrylic acid (salt) monomer or a hydrogel crosslinked polymer after polymerization is A part or all of the salt form, and the salt form is preferably a monovalent salt form such as a sodium salt form, a lithium salt form, a potassium salt form, an ammonium salt form, an amine, and more preferably an alkali metal salt form.
  • a sodium salt type and / or a potassium salt type are more preferable, and a sodium salt type is particularly preferable from the viewpoint of cost and physical properties.
  • the acrylic acid (salt) monomer preferably contains a polymerization inhibitor.
  • the polymerization inhibitor is not particularly limited, and examples thereof include polymerization inhibitors described in Patent Documents 20 and 21, N-oxyl compounds, manganese compounds, substituted phenol compounds and the like disclosed in International Publication No. 2008/096713. Can be mentioned. Of these, substituted phenols are preferred, and methoxyphenols are particularly preferred.
  • the content of methoxyphenols in the acrylic acid (salt) monomer is preferably 10 to 200 ppm, and in the following order, preferably 5 to 160 ppm, 10 to 160 ppm, 10 to 100 ppm, and 10 to 80 ppm. ⁇ 70 ppm is most preferred.
  • an internal cross-linking agent is used as necessary in the polymerization.
  • the internal cross-linking agent known ones can be used. For example, N, N′-methylenebis (meth) acrylamide, (poly) ethylene glycol di (meth) acrylate, (poly) propylene glycol di (meth) acrylate, trimethyl Roll propane tri (meth) acrylate, glycerin tri (meth) acrylate, glycerin acrylate methacrylate, ethylene oxide modified trimethylolpropane tri (meth) acrylate, pentaerythritol hexa (meth) acrylate, triallyl cyanurate, triallyl isocyanurate, tri Allyl phosphate, triallylamine, poly (meth) allyloxyalkane, (poly) ethylene glycol diglycidyl ether, glycerol diglycidyl ether,
  • the amount of the internal cross-linking agent used can be appropriately determined depending on the desired properties of the water-absorbing agent, but is preferably 0.001 to 5 mol%, preferably 0.005 to 5%, based on the entire acrylic acid (salt) monomer. 2 mol% is more preferable, and 0.01 to 1 mol% is still more preferable.
  • the amount used is less than 0.001 mol%, the water-soluble resin powder obtained has a large amount of water-soluble components, and the amount of water absorption under pressure cannot be secured sufficiently.
  • the amount used exceeds 5 mol%, the crosslink density of the resulting water-absorbent resin powder becomes high and the amount of water absorption becomes insufficient.
  • the internal cross-linking agent may be added in total to the acrylic acid (salt) monomer, or a part thereof may be added to the hydrogel during polymerization and / or before drying after polymerization.
  • a surfactant and / or a dispersant is added to the acrylic acid (salt) monomer aqueous solution during preparation or after preparation before the polymerization step. It is preferable to add and stably suspend the generated bubbles, and by appropriately designing the type and amount of the surfactant and / or dispersant, a water-absorbent resin powder having desired physical properties can be obtained.
  • the surfactant is preferably a non-polymer compound, and the dispersant is preferably a polymer compound.
  • the surface tension of the obtained water absorbent resin powder is 60 [mN / m].
  • it is added to an acrylic acid (salt) monomer aqueous solution and / or a subsequent process (for example, a surface cross-linking process) so as to be 65 [mN / m] or more and 70 [mN / m] or more.
  • the upper limit is not particularly limited, but is, for example, about 75 [mN / m], and preferably about 73 [mN / m].
  • a water-absorbing resin powder or an acrylic acid (salt) monomer and a reactive or polymerizable surfactant such as an unsaturated polymerizable group (particularly ⁇ , ⁇ -Use of a surfactant having an unsaturated double bond) or a reactive group (hydroxyl group, amino group) is preferred, and a hydrophilic surfactant (HLB; 1-18, especially 8) having high solubility in water.
  • ⁇ 15 is also preferred.
  • Examples of the polymerization method for obtaining the water-absorbent resin powder of the present invention include spray polymerization, droplet polymerization, bulk polymerization, precipitation polymerization, aqueous solution polymerization or reverse phase suspension polymerization. Is preferably aqueous solution polymerization, reverse phase suspension polymerization, spray polymerization or droplet polymerization in which the monomer is an aqueous solution, and aqueous solution polymerization is particularly preferable. In these polymerizations, if necessary, foam polymerization, particularly polymerization in which bubbles are dispersed, is performed, and the internal cell ratio (%) is controlled.
  • the aqueous solution polymerization is a method of polymerizing an aqueous monomer solution without using a dispersion solvent.
  • the reverse phase suspension polymerization is a method in which an aqueous monomer solution is suspended in a hydrophobic organic solvent for polymerization.
  • a hydrophobic organic solvent for polymerization for example, U.S. Pat. Nos. 4,093,764, 4,367,323, 4,446,261, Nos. 4,683,274 and 5,244,735.
  • Monomers, polymerization initiators and the like disclosed in these patent documents can also be applied to the present invention.
  • the concentration of the aqueous monomer solution during the polymerization is not particularly limited, but is preferably 20% by weight to saturated concentration, more preferably 25 to 80% by weight, still more preferably 30 to 70% by weight. When the concentration is less than 20% by weight, productivity is lowered, which is not preferable. Polymerization in a slurry (acrylic acid aqueous dispersion) in which at least a part of the monomer exists in a solid state is observed to decrease in physical properties. (Kaihei 1-318021).
  • the polymerization step in the present invention can be carried out at normal pressure, reduced pressure, or increased pressure, but is preferably carried out at normal pressure (or in the vicinity thereof, usually ⁇ 10 mmHg).
  • a deoxygenation step of dissolved oxygen in the monomer aqueous solution may be provided as necessary during the polymerization.
  • Bubbles may be formed by dispersing bubbles by introducing an inert gas.
  • the temperature of the acrylic acid (salt) monomer aqueous solution at the start of polymerization is preferably 15 to 130 ° C., more preferably 20 to 120 ° C., although it depends on the type of polymerization initiator used.
  • aqueous polymerization is employed as a method for polymerizing an acrylic acid (salt) monomer aqueous solution from the viewpoint of physical properties of the water-absorbing agent (for example, water absorption rate and liquid permeability) and ease of polymerization control.
  • continuous aqueous solution polymerization is more preferable, high concentration continuous aqueous solution polymerization and / or high temperature starting continuous aqueous solution polymerization is further preferable, and high concentration / high temperature starting continuous aqueous solution polymerization is particularly preferably employed.
  • a preferable form of the aqueous solution polymerization is kneader polymerization or belt polymerization, specifically, continuous belt polymerization (disclosed in US Pat. Nos. 4,893,999, 6,241,928, US Patent Application Publication No. 2005/215734, etc.), Examples thereof include continuous kneader polymerization and batch kneader polymerization (disclosed in US Pat. Nos. 6,987,151 and 6,710,141).
  • the water-absorbing agent can be produced with high productivity.
  • the preferred form of the high concentration / high temperature starting continuous aqueous solution polymerization is not particularly limited.
  • the polymerization start temperature is preferably 40 ° C. or higher, more preferably 50 ° C. or higher, further preferably 60 ° C. or higher, particularly preferably 70 ° C. or higher, and most preferably 80 ° C. or higher.
  • the upper limit is the monomer most contained in the aqueous solution, preferably the boiling point of acrylic acid).
  • the monomer concentration is preferably 40% by weight or more, more preferably 45% by weight or more, further preferably 50% by weight or more (the upper limit is 90% by weight or less, preferably 80% by weight or less, more preferably 70% by weight). % Or less).
  • Foaming is further promoted by using high concentration / high temperature starting continuous aqueous solution polymerization.
  • the maximum temperature reached during polymerization is high, specifically 100 ° C. or higher, more preferably 100 to 130 ° C., and further preferably 105 to 120 ° C.
  • the monomer concentration may be such that the solid content concentration of the hydrogel crosslinked polymer after polymerization is within the above range. By setting the monomer concentration within the above range, the stability of fine bubbles is increased, and the present invention is particularly advantageous.
  • the polymerization start time (the time from the addition of the polymerization initiator to the start of the polymerization) exceeds 0 and is 300 seconds from the viewpoint of suppressing the reduction of bubbles in the aqueous monomer solution. Is preferably within 1 to 240 seconds.
  • the polymerization start time exceeds 300 seconds, the internal cell ratio of the water-absorbent resin powder may be lowered, which is not preferable.
  • the polymerization method is preferably used in a large scale production apparatus with a large production amount per line, and the production amount is preferably 0.5 [t / hr] or more, and 1 [t / hr].
  • the above is more preferable, 3 [t / hr] or more is more preferable, 5 [t / hr] or more is more preferable, and 10 [t / hr] or more is particularly preferable.
  • water-containing gel the water-containing gel-like crosslinked polymer obtained through the above-described polymerization step and the like is gel-pulverized to form a particulate water-containing gel (hereinafter referred to as “particulate water-containing gel”). Is an optional step.
  • the above hydrous gel is finely divided so that the gel during or after polymerization is finer with a kneader or meat chopper than necessary for heat removal during polymerization and drying efficiency. Is done.
  • the weight average particle diameter (D50) of the hydrogel is preferably 0.5 to 4 mm, more preferably 0.3 to 3 mm, and still more preferably 0.5 to 2 mm.
  • the weight average particle size (D50) can be measured using the wet classification method described in paragraph [0091] of JP-A No. 2000-63527.
  • the present invention is a continuous kneader polymerization in which a hydrogel crosslinked polymer produced during polymerization is gel-pulverized, or a process in which the polymerization process is performed by continuous belt polymerization, and the resulting hydrogel crosslinked polymer is subjected to a gel grinding process.
  • the method is preferred.
  • This step is not particularly limited as long as the desired moisture content can be obtained as a drying method, and various methods can be adopted. Specifically, it may be dried simultaneously with the polymerization, but preferably after the polymerization, heating drying, hot air drying, vacuum drying, infrared drying, microwave drying, azeotropic dehydration drying with a hydrophobic organic solvent, high-temperature steam High-humidity drying using
  • the drying temperature is preferably 60 to 250 ° C, more preferably 100 to 220 ° C, still more preferably 120 to 200 ° C.
  • the drying time may be appropriately selected within the range of 1 minute to 5 hours, 10 minutes to 2 hours.
  • the water content (% by weight) of the dried polymer after drying is determined from loss on drying (1 g of powder or particles is dried at 180 ° C. for 3 hours). Further, the resin solid content after drying (100-water content) is preferably 80% by weight or more, more preferably 85 to 99% by weight, and still more preferably 90 to 98% by weight.
  • the “moisture content” in this step refers to the weight loss when the object to be measured is dried at 180 ° C. for 3 hours, expressed as a ratio (% by weight) to the weight before drying.
  • Optional pulverization / classification step This step is a step of pulverizing and / or classifying the dried polymer obtained in the drying step to obtain a water-absorbent resin powder having a specific particle size.
  • the (2-3) gel pulverization step is different in that the object to be pulverized has undergone a drying step. Further, the water absorbent resin powder after the pulverization step may be referred to as a pulverized product.
  • the pulverization / classification step is not necessary and is an optional step, preferably the classification step is performed, If necessary, a pulverization step may be performed to adjust the physical properties described in (2-5-1 particle size).
  • the weight average particle diameter (D50) of the water-absorbent resin powder before surface crosslinking is preferably 200 to 600 ⁇ m, more preferably 200 to 550 ⁇ m, and more preferably 250 to 500 ⁇ m from the viewpoints of water absorption speed, liquid permeability, water absorption capacity under pressure, and the like. Is more preferable, and 350 to 450 ⁇ m is particularly preferable.
  • the content (particle content) of particles of 150 ⁇ m or more and less than 850 ⁇ m is 95% by weight or more (upper limit: 100% by weight).
  • the particle content is less than 95% by weight, the particulate water-absorbing agent after surface cross-linking has a large residual amount of epoxy compound (particularly glycidyl-based cross-linking agent), and the absorption capacity (CRC) and absorption under pressure are absorbed.
  • the balance with magnification (AAP) is poor.
  • the water-absorbent resin powder before surface crosslinking has a particle content (particle content) of 150 ⁇ m or more and less than 850 ⁇ m of 70 to 100 wt%, 80 to 100 wt%, 90 to 100 wt%, 95 More preferably, it is ⁇ 100% by weight.
  • 0 to 5% by weight is preferable, 0 to 3% by weight is more preferable, and 0 More preferred is ⁇ 1% by weight.
  • 710 ⁇ m non-passage is 0 to 5% by weight, more preferably 0 to 3% by weight, still more preferably 0 to 1% by weight.
  • the ratio of the particle size is preferably 150 ⁇ m or more and less than 850 ⁇ m, more preferably 150 ⁇ m or more and less than 710 ⁇ m, in terms of water absorption speed, liquid permeability, water absorption capacity under pressure, etc., is preferably 95% by weight or more, and 98% by weight or more. Is more preferably 99% by weight or more (the upper limit is 100% by weight).
  • the ratio of particles of 150 ⁇ m or more and less than 600 ⁇ m is preferably 80% by weight or more, and more preferably 85% by weight, 90% by weight or more, and 92% by weight or more (the upper limit is 100% by weight).
  • the proportion of particles of 500 to 150 ⁇ m is preferably 60% by weight or more, more preferably 65% by weight or more, still more preferably 67% by weight or more, and particularly preferably 80% by weight or more (upper limit) Is 100% by weight).
  • the production method of the present invention preferably includes a first classification step before surface crosslinking, and more preferably And a second classification step after surface cross-linking.
  • the said particle diameter is applied not only to the water-absorbing resin powder before surface cross-linking but also to the final water-absorbing agent described in (3) below.
  • the shape of the water-absorbent resin powder used in the present invention is preferably a spherical shape, an aggregate thereof, or an irregular crushed shape, and more preferably an irregular crushed shape or a granulated product thereof from the viewpoint of water absorption speed.
  • Optional fine powder recovery step As described in Patent Documents 20 and 21, a fine powder recovery step may optionally be included in the polymerization step, the drying step, and the like.
  • the method for producing a water-absorbing agent of the present invention is a method for producing a particulate water-absorbing agent in which polyacrylic acid (salt) -based water-absorbing resin powder is surface-crosslinked with a glycidyl-based cross-linking agent.
  • This is a production method in which the content of particles having a particle diameter of 150 ⁇ m or more and less than 850 ⁇ m in the powder is 95% by weight or more, and an organic surface crosslinking agent (excluding glycidyl crosslinking agent) that is solid at room temperature (excluding glycidyl-based crosslinking agent) is used.
  • Preferred melting points and melting point differences in the present invention are in the ranges described at the beginning.
  • an organic surface cross-linking agent (except for a glycidyl-based cross-linking agent) that is solid at room temperature (melting point: 25 ° C. or higher) is also referred to as a “second cross-linking agent”.
  • an organic surface cross-linking agent (except for a glycidyl-based cross-linking agent) that is liquid at ordinary temperature (melting point less than 25 ° C.) is further used as the third cross-linking agent.
  • an organic surface cross-linking agent (except for a glycidyl-based cross-linking agent) that is liquid at normal temperature (melting point less than 25 ° C.) is also referred to as a “third cross-linking agent”.
  • the present invention is characterized in that a glycidyl-based crosslinking agent and an organic surface crosslinking agent that is solid at room temperature (excluding glycidyl-based crosslinking agents) are used in combination, and the combination includes a plurality of different crosslinking agents (particularly glycidyl-based crosslinking agents).
  • the surface of the water-absorbent resin powder is cross-linked with an organic cross-linking agent that is solid at room temperature, optionally an organic cross-linking agent that is liquid at normal temperature, and further a polyvalent metal ion (inorganic ionic cross-linking agent).
  • cross-linking agents after mixing a plurality of different cross-linking agents with the water-absorbent resin powder, or after mixing and reacting the cross-linking agent with the water-absorbent resin powder, another different cross-linking agent is mixed with the water-absorbent resin powder. Any form to be reacted is included in the “combination of crosslinking agents”.
  • a plurality of different cross-linking agents are water-absorbing.
  • the resin powder is reacted after mixing.
  • the residual amount of the glycidyl-based crosslinking agent can be reduced, and a water absorbing agent having high physical properties (high AAP / high CRC) can be obtained.
  • a glycidyl crosslinking agent and an organic surface crosslinking agent that is solid at room temperature are added to the water-absorbent resin powder as separate aqueous solutions or mixed aqueous solutions, followed by heat treatment.
  • a glycidyl crosslinking agent and an organic surface crosslinking agent that is solid at room temperature are added to the water-absorbent resin powder as an aqueous solution or as an aqueous solution containing both crosslinking agents, followed by heat treatment. It is preferable.
  • an aqueous solution containing a glycidyl-based crosslinking agent and an organic surface crosslinking agent solid at room temperature (excluding the glycidyl-based crosslinking agent) is added to the water-absorbent resin powder, followed by heat treatment.
  • a suitable heat treatment temperature will be described later.
  • the glycidyl-based cross-linking agent in addition to the combined use of a glycidyl crosslinking agent and an organic surface crosslinking agent that is solid at room temperature (excluding glycidyl crosslinking agent), more preferably, a third crosslinking agent Alternatively or in addition to the third cross-linking agent, as a fourth (fourth after the liquid organic surface cross-linking agent at room temperature), the glycidyl-based cross-linking agent may be mixed with the glycidyl cross-linking agent or in a separate step at a normal temperature. A polyvalent metal cation is further used in combination as an inorganic cationic surface cross-linking agent. By this method, the residual glycidyl-based crosslinking agent can be further reduced, the fluidity at the time of moisture absorption is excellent, and a water absorbing agent having high physical properties (high CRC and AAP) can be obtained.
  • the glycidyl-based cross-linking agent is a water-soluble or water-insoluble epoxy group-containing compound, preferably water-soluble (the solubility (water solubility) is 20 when 10 parts by weight of the cross-linking agent is added to 90 parts by weight of water at room temperature).
  • polymer crosslinking agent for example, a polymer of glycidyl acrylate
  • non-polymeric crosslinking agent for example, a polymer of glycidyl acrylate
  • non-polymeric crosslinking agent preferably non-polymeric glycidyl-based crosslinking agents in terms of physical properties, More preferred than polyvalent glycidyl crosslinking agents.
  • the molecular weight of the non-polymeric crosslinking agent is preferably 150 to 3000, more preferably 200 to 1000, from the viewpoint of physical properties.
  • examples of the glycidyl-based crosslinking agent include liquid (liquid) or solid, preferably liquid epoxy compounds, particularly glycidyl compounds at room temperature.
  • the viscosity of the liquid (liquid) cross-linking agent at room temperature is determined by its structure and is, for example, in the range of 5 to 30000 cps (25 ° C., Heppler viscometer or B-type viscometer).
  • glycidol (melting point: -54 ° C.) is exemplified as the monoglycidyl-based crosslinking agent used in the present invention.
  • the polyvalent glycidyl-based crosslinking agent water-soluble epoxy compounds that are liquid at room temperature, ethylene glycol diglycidyl ether, diethylene glycol diglycidyl ether, polyethylene diglycidyl ether, glycerol polyglycidyl ether, diglycerol polyglycidyl ether, polyglycerol Examples thereof include polyglycidyl ether, propylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, sorbitol polyglycidyl ether, pentalysitol polyglycidyl ether, and trimethylolpropane polyglycidyl ether.
  • polyvalent epoxy and further polyglycidyl also known as polyvalent glycidyl
  • the number is preferably from 2 to 200, more preferably from 2 to 20, and particularly preferably from 2 to 15.
  • the water absorption rate is preferably 90% by weight or more, particularly preferably 100% by weight). It is more preferable at the point which improves.
  • Epoxy crosslinking agents are typically marketed under the trade name Denacol of Nagase Chemtech, and such product catalogs are also referred to as necessary.
  • the addition amount of the glycidyl-based crosslinking agent may be appropriately set depending on the physical properties of the obtained water-absorbent resin powder, the type of the surface-crosslinking agent to be used, and the like, and is not particularly limited, but is 0 for 100 parts by weight of the water-absorbent resin powder. 0.001 to 10 parts by weight, preferably 0.005 to 5 parts by weight, more preferably 0.01 to 1 part by weight, still more preferably 0.02 to 0.5 parts by weight, and 0.02 to 0 parts by weight. .1 part by weight is particularly preferable in terms of improving water absorption characteristics such as water absorption capacity under pressure.
  • the crosslinking agent is mixed with the water-absorbent resin powder as a solution using a solvent, particularly water, and further as an aqueous solution.
  • the water used in the aqueous solution of the crosslinking agent is not particularly limited, but tap water and ion-exchanged water are preferable, and ion-exchanged water is more preferable in that it does not inhibit water absorption characteristics and surface crosslinking reaction.
  • the amount of water added may be appropriately set depending on the physical properties of the water-absorbing agent to be obtained, the type of surface cross-linking agent to be used, and the like, and is not particularly limited, but is 0.5 to 10 with respect to 100 parts by weight of the water-absorbing resin powder. Part by weight is preferable, 1 to 8 parts by weight is more preferable, and 2 to 5 parts by weight is particularly preferable in terms of improving water absorption characteristics such as water absorption capacity under pressure.
  • an organic solvent described later particularly a hydrophilic organic solvent, a lower alcohol, particularly a monohydric alcohol or ketone having 1 to 4 carbon atoms may be used in an amount of about 0 to 10 parts by weight.
  • organic surface crosslinking agent / second cross-linking agent solid at normal temperature in addition to the glycidyl crosslinking agent, an organic surface crosslinking agent that is solid at room temperature (excluding the glycidyl crosslinking agent) is used in combination as the second crosslinking agent.
  • the organic surface crosslinking agent that is solid at normal temperature (melting point: 25 ° C. or higher) preferably used in the present invention may be a compound that does not contain a glycidyl group, preferably a compound that does not contain an epoxy group, and more preferably. Is a non-polymeric organic crosslinking agent.
  • solid alcohols such as saturated dihydric alcohols, saturated trihydric alcohols, saturated tetrahydric alcohols, and unsaturated glycols, cyclic compounds such as cyclic (carbonic acid) esters, diamine compounds, and amines such as amino alcohols.
  • cyclic compounds such as cyclic (carbonic acid) esters
  • diamine compounds such as amino alcohols.
  • amines such as amino alcohols.
  • examples thereof include compounds and saturated fatty acids, and more specifically, the following compounds are exemplified.
  • These compounds, non-polymeric organic compounds, especially solid surface cross-linking agents are preferably heated, especially heated and melted, and the aqueous solution of the cross-linking agent is adjusted, stored and / or transported in the heated state.
  • the upper limit of the melting point is usually 150 ° C., preferably 130 ° C., more preferably 100 ° C., particularly 95 ° C., 85 ° C., 75 ° C. It is preferable in order. Because of this melting point, even if the solvent (water) volatilizes during the heat treatment for surface crosslinking, it remains liquid and uniform surface crosslinking proceeds, and even if it remains in the final product after the crosslinking reaction, it is a solid at room temperature.
  • the scope of rights of the present invention is not particularly bound by such theory.
  • a dehydration-reactive surface cross-linking agent that is preferably solid at normal temperature, and further, a saturated dihydric alcohol, a saturated trihydric alcohol, a saturated tetrahydric alcohol, and a cyclic (carbonic acid) ester are used.
  • a dehydration-reactive surface cross-linking agent may be used as an internal cross-linking agent by being used for a monomer during polymerization or a gel after polymerization, that is, it can be used as a dehydration-reactive cross-linking agent.
  • saturated dihydric alcohol examples include meso-2,3-butanediol (melting point: 34.4 ° C.), tetramethylethylene glycol (melting point: 38 ° C.) and hexahydrate thereof (melting point: 46-47 ° C.), hexanemethyl Trimethylene glycol (melting point 126-128 ° C), 2,2-dimethyl-1,3-petanetanediol (melting point 60-63 ° C), 2,2,4-trimethyl-1,3-pentanediol (melting point 52 ° C) ), 2,5-hexanediol (melting point 43-44 ° C.), 1,6-hexanediol (melting point 42 ° C.), 1,8-octanediol (melting point 60 ° C.), 1,9-nonanediol (melting point 45 ° C.) ), 1,10-decanediol (melting
  • Examples of the unsaturated glycol include cis-2,5-dimethyl-3-hexene-2,5-diol (melting point: 69 ° C.), cis-2,5-dimethyl-3-hexene-2,5-diol (melting point: 77 ), Racemic-2,6-octadiene-4,5-diol (melting point: 48 ° C.), and the like.
  • saturated trihydric alcohol examples include 2-methyl-2,3,4-butanetriol (melting point: 49 ° C.), 2,3,4-hexanetriol (melting point: 47 ° C.), 2,4-dimethyl-2,3, Examples include 4-hexanetriol (melting point 75 ° C.), dimethyl petaneglycerin (melting point 83 ° C.), 2,4-dimethyl-2,3,4-pentanetriol (melting point 99 ° C.), trimethylolpropane (melting point 58 ° C.), and the like. It is done.
  • saturated tetrahydric alcohol examples include 1,2,4,5-hexanetetrol (melting point 88 ° C.), 1,2,5,6-hexanetetrol (melting point 96 ° C.) and the like.
  • cyclic ester examples include alkylene carbonates such as ethylene carbonate (melting point: 35 to 38 ° C.), 5,5-dimethyl-4-methylene-1,3-dioxolan-2-one (melting point: 26 ° C.), 2,2- Pentamethylene-1,3-dioxolan-4-one (melting point 32 to 35 ° C.), 1,3-dioxan-2-one (melting point 48 ° C.), 4,5-dimethyl-1,3-dioxol-2-one (Melting point: 78 ° C.).
  • alkylene carbonates such as ethylene carbonate (melting point: 35 to 38 ° C.), 5,5-dimethyl-4-methylene-1,3-dioxolan-2-one (melting point: 26 ° C.), 2,2- Pentamethylene-1,3-dioxolan-4-one (melting point 32 to 35 ° C.), 1,3-dioxan-2-one (mel
  • cyclic compounds include oxazolidinone compounds such as (S) -4-benzyl-2-oxazolidinone (melting point: 86 to 88 ° C.), 5-methyl-5- (3-isopropoxy-4-methoxyphenyl) -2- Oxazolidinone (melting point 67-69.5 ° C.), 5-methyl-5- (3-ethoxy-4-methoxyphenyl) -2-oxazolidinone (melting point 63-65 ° C.), oxazolidinone (melting point 86-89 ° C.), etc. It is done.
  • oxazolidinone compounds such as (S) -4-benzyl-2-oxazolidinone (melting point: 86 to 88 ° C.), 5-methyl-5- (3-isopropoxy-4-methoxyphenyl) -2- Oxazolidinone (melting point 67-69.5 ° C.), 5-methyl-5- (3-ethoxy-4-methoxyphenyl
  • diamine compound examples include tetramethylene diamine (melting point 27 ° C.), hexamethylene diamine (melting point 42 ° C.), heptamethylene diamine (melting point 28 to 29 ° C.), octamethylene diamine (melting point 52 ° C.), nonamethylene diamine (melting point 37 .5 ° C.) and the like.
  • amino alcohol examples include diisopropanolamine (melting point: 43 ° C.), triisopropanolamine (melting point: 57.2 ° C.), 1-aminopentan-5-ol (melting point: 36 ° C.), and the like.
  • organic surface cross-linking agents selected from polyhydric alcohols, cyclic carbonates and cyclic carbonates, and also selected from cyclic carbonates and cyclic carbonates
  • An organic surface cross-linking agent particularly a cyclic carbonate, is preferably used.
  • the cyclic carbonic acid ester and the cyclic carbonic acid amide are selected from the above-mentioned compounds, particularly alkylene carbonates and oxazolidinone compounds.
  • ethylene carbonate melting point: 36 ° C.
  • oxazolidinone melting point: 87-91 ° C.
  • ethylene carbonate is used. .
  • the amount of organic crosslinking agent that is solid at room temperature may be appropriately set depending on the properties of the water-absorbing agent to be obtained and the type of surface crosslinking agent to be used. Although not particularly limited, it is preferably 0.001 to 10 parts by weight, more preferably 0.005 to 5 parts by weight, still more preferably 0.01 to 1 part by weight, based on 100 parts by weight of the water absorbent resin powder. 0.02 to 0.5 parts by weight is even more preferable, and 0.02 to 0.1 parts by weight is particularly preferable in that the residual epoxy compound can be reduced.
  • a surface crosslinking agent that is liquid at room temperature (excluding the glycidyl crosslinking agent) is preferably used in combination as the third crosslinking agent. That is, the present invention preferably further uses a surface cross-linking agent that is liquid at normal temperature (melting point less than 25 ° C., and further in the above range 0 ° C. or less, ⁇ 10 ° C. or less, ⁇ 20 ° C. or less, ⁇ 25 ° C. or less). .
  • the lower limit of the melting point is not particularly limited, and is, for example, about ⁇ 200 ° C., further about ⁇ 100 ° C.
  • 2,2-dimethyl-1,3-butanediol (melting point: 10 ° C.), ethylene glycol (melting point: ⁇ 13 ° C.), ethylenediamine (melting point: 8.5 ° C.), glycerin (melting point: 18 ° C.), propylene carbonate (Melting point -55 ° C), propylene glycol (melting point -59 ° C), 1,3-propanediol (-28 ° C), glycerin (18 ° C), 1,4-butanediol (20 ° C), 1,3- Butanediol (-50 ° C or lower), 2-methyl-2,4-pentanediol (melting point -40 ° C), ethanolamine (melting point 10 ° C), triethanolamine (20.5 ° C), 1,5-pentanediol (Melting point ⁇ 18 ° C.) and the like.
  • the organic surface cross-linking agent that is liquid at room temperature is preferably selected from polyhydric alcohols and amino alcohols, and moreover, polyhydric alcohols and amino alcohols having 2 to 6 carbon atoms. More preferably, the diol having 3 to 6 carbon atoms is still more preferable, and the diol having 3 carbon atoms is particularly preferable.
  • these polyhydric alcohols can be obtained in a predetermined amount, which will be described later, and / or contained (separately added) in the obtained water-absorbing agent, whereby a surface hydrophilized water-absorbing agent can be obtained with less dust.
  • the amount of the organic cross-linking agent that is liquid at room temperature may be appropriately set depending on the properties of the obtained water-absorbing agent and the type of surface cross-linking agent to be used, and is not particularly limited.
  • the amount is preferably 0 to 10 parts by weight, more preferably 0.01 to 10 parts by weight, still more preferably 0.05 to 5 parts by weight, and still more preferably 0.1 to 1 part by weight with respect to parts by weight. Within the above range, it is possible to obtain a water-absorbent resin powder with a small remaining amount in the obtained water-absorbent resin powder and a small amount of dust.
  • the fourth crosslinking agent is a polyvalent metal cation that is solid at ordinary temperature, and further is an inorganic cationic surface crosslinking agent that is solid at ordinary temperature. Used together.
  • the fourth crosslinking agent may be used in combination with the mixing of the glycidyl crosslinking agent or in a separate step.
  • the organic cross-linking agent that is liquid at room temperature as the third cross-linking agent is arbitrary, and the third cross-linking agent is not used (0), and only the polyvalent metal cation is used at room temperature as the fourth cross-linking agent. More preferably, the third crosslinking agent and the fourth crosslinking agent are also used simultaneously or separately.
  • the polyvalent metal compound that can be used for the polyvalent metal cation in the present invention is preferably water-soluble.
  • the polyvalent metal cation is essentially divalent or higher, preferably divalent to tetravalent, and preferably an inorganic acid salt or organic acid salt of a trivalent or tetravalent cation.
  • water-soluble refers to a compound that dissolves in 1 g or more, preferably 10 g or more, in 100 g of water (25 ° C.).
  • the polyvalent metal compound containing the polyvalent metal cation may be mixed as it is (mainly in solid form) with the water-absorbent resin particles.
  • a water-soluble polyvalent metal compound is used. It is preferable to mix an aqueous solution with water absorbent resin powder.
  • the polyvalent metal cation that can be used in the present invention preferably contains at least one metal selected from a typical metal and a transition metal having a group number of 4 to 11.
  • Mg, Ca, Ti, Zr, V, Cr, Mn, Fe, Co, Ni, Pd, Cu, Zn, Cd, and Al are preferably included, and Mg, Ca, Zn, and Al are more preferable.
  • Al is particularly preferable.
  • the counter anion may be either organic or inorganic, and is not particularly limited.
  • a polyvalent metal salt of an organic acid for example, anisic acid, benzoic acid, p-hydroxybenzoic acid, formic acid, valeric acid, citric acid, glycolic acid, glyceric acid, glutaric acid, chloroacetic acid, chloropropionic acid , Cinnamic acid, succinic acid, acetic acid, tartaric acid, lactic acid, pyruvic acid, fumaric acid, propionic acid, 3-hydroxypropionic acid, malonic acid, maleic acid, butyric acid, isobutyric acid, imidinoacetic acid, malic acid, isothionic acid, methyl
  • polyvalent metal salts of fatty acids such as maleic acid, adipic acid, itaconic acid, crotonic acid, oxalic acid, salicylic acid, gluconic acid, gallic acid, sorbic acid and stearic acid.
  • tartrate and lactate are preferable, and lactate such as aluminum lactate
  • water-soluble aluminum salts such as aluminum chloride, polyaluminum chloride, aluminum sulfate, aluminum nitrate, potassium bissulfate aluminum, sodium bissulfate aluminum; calcium chloride, calcium nitrate, magnesium chloride
  • water-soluble alkaline earth metal salts such as magnesium sulfate and magnesium nitrate
  • transition metal salts such as zinc chloride, zinc sulfate, zinc nitrate, copper sulfate, cobalt chloride, zirconium chloride, zirconium sulfate, and zirconium nitrate.
  • an aluminum salt is particularly preferable among inorganic polyvalent metal salts.
  • aluminum sulfate is preferable, and water-containing crystal powder such as aluminum sulfate 14-18 hydrate (and its aqueous solution). Can be most preferably used.
  • the method for mixing the polyvalent metal salt compound is an aqueous solution containing the polyvalent metal compound in the water-absorbent resin powder, particularly a polyvalent metal cation concentration of 1 to 60% by weight, more preferably 10 to It is preferable to mix as a 50% by weight aqueous solution.
  • the polyvalent metal cation When the polyvalent metal cation is mixed with the water-absorbent resin powder simultaneously with the glycidyl surface cross-linking agent, it is heated at the surface cross-linking temperature described later after mixing.
  • the mixture When separately mixed with the surface cross-linking agent, the mixture may be heated at 40 to 150 ° C., more preferably about 60 to 100 ° C. after the mixing.
  • heating is not necessary.
  • the amount of water used is preferably 0.1 to 5 parts by weight, more preferably 0.5 to 3 parts by weight with respect to 100 parts by weight of the water absorbent resin powder. More preferably, a polyhydric alcohol and / or ⁇ -hydroxycarboxylic acid is used in combination during mixing.
  • the polyhydric alcohol and / or ⁇ -hydroxycarboxylic acid is appropriately selected from the various compounds described above.
  • the amount of polyhydric alcohol and / or ⁇ -hydroxycarboxylic acid is less than water and is 0 to 4 parts by weight, 0.01 to 3 parts by weight, and more preferably 0.1 to 0.5 parts by weight with respect to 100 parts by weight of the water absorbent resin powder. It is preferably used in parts by weight.
  • the amount of the polyvalent metal compound used is preferably 0 to 3 parts by weight, more preferably 0.001 to 3 parts by weight, more preferably 0.01 to 2 parts by weight based on 100 parts by weight of the water-absorbent resin powder as the polyvalent metal cation. Part by weight is even more preferred, 0.02 to 1 part by weight is still more preferred, 0.03 to 0.9 part by weight is particularly preferred, and 0.05 to 0.8 part by weight is most preferred.
  • the polyvalent metal cation is less than 0.001 part by weight with respect to 100 parts by weight of the water-absorbent resin powder, the improvement of FSC is not sufficient.
  • the AAP is greatly reduced by mixing. There is a risk.
  • the surfactant when mixing the surface cross-linking agent solution with the water absorbent resin powder, the surfactant is used in an amount not exceeding the effects of the present invention, for example, exceeding 0 part by weight and not more than 10 parts by weight.
  • more than 0 parts by weight and 5 parts by weight or less, more preferably more than 0 parts by weight and 1 part by weight or less, still more preferably 0.0005 to 1 part by weight can be present together.
  • the surfactant used is disclosed in US Pat. No. 7,473,739.
  • the concentration of the glycidyl-based crosslinking agent and the second and third crosslinking agents is appropriately determined.
  • the total concentration of the three types of surface crosslinking agents in one aqueous solution of the surface crosslinking agent is preferably
  • the aqueous solution is 1 to 80% by weight, more preferably 5 to 60% by weight, still more preferably 10 to 40% by weight, and particularly preferably 15 to 30% by weight.
  • the aqueous solution is not limited to a solvent containing only water, and a solvent other than water is 0 to 50% by weight, 0 to 30% by weight, 0 to 10% by weight of an organic solvent, particularly a hydrophilic organic solvent (especially a boiling point of 150 May be included as a solvent.
  • an organic solvent particularly a hydrophilic organic solvent (especially a boiling point of 150 May be included as a solvent.
  • the hydrophilic organic solvent to be used include primary alcohols having 1 to 4 carbon atoms, further 2 to 3 carbon atoms, and lower ketones having 4 or less carbon atoms such as acetone.
  • water-insoluble inorganic fine particles Simultaneously with or separately from the mixing of the glycidyl-based crosslinking agent, water-insoluble inorganic fine particles may be further used in combination. That is, the water-absorbing agent according to the present invention preferably contains water-insoluble inorganic fine particles.
  • the water-insoluble inorganic fine particles can be added at the same time as the mixing step of the glycidyl-based crosslinking agent or in a separate step.
  • the water-insoluble inorganic fine particles may be preliminarily dispersed in a glycidyl-based crosslinking agent and / or an aqueous solution, or may be preliminarily mixed in the water absorbent resin powder before mixing the crosslinking agent.
  • the crosslinking agent and water-insoluble inorganic fine particles may be mixed simultaneously, or water-insoluble inorganic fine particles may be further mixed with the water-absorbing resin (particulate water-absorbing agent) after surface crosslinking.
  • the water-insoluble inorganic fine particles are further mixed with the water-absorbing resin (particulate water-absorbing agent) after surface crosslinking.
  • the water-insoluble inorganic fine particles are not particularly limited as long as the water-absorbing agent prevents the water-absorbing agent particles from coming into close contact with each other when the water-absorbing agent comes into contact with the aqueous liquid and improves the flow of the aqueous liquid.
  • water-insoluble inorganic element-containing fine powders are preferable, such as fine particles of inorganic compounds such as clay, kaolin, bentonite, silicon dioxide, titanium oxide, aluminum oxide, calcium lactate, metal soap (polyvalent metal salt of long chain fatty acid), etc.
  • a fine powder of carboxylate is mentioned.
  • Such fine particles of an inorganic compound are preferable because they improve the hygroscopic fluidity, and silicon dioxide is particularly preferable in terms of improving the hygroscopic fluidity.
  • the primary particle volume average particle size of the water-insoluble inorganic fine particles is preferably 1 ⁇ m or less, more preferably 0.5 ⁇ m or less, still more preferably 0.1 ⁇ m or less, and particularly preferably 0.05 ⁇ m or less.
  • the lower limit of the volume average particle diameter of the water-insoluble inorganic fine particles is not particularly limited, but is usually 0.005 ⁇ m or more and preferably 0.007 ⁇ m or more.
  • the mixing method of the water-absorbent resin powder and the water-insoluble inorganic fine particles may be dry blending, or may be mixed with a slurry of water-insoluble inorganic fine particles as an aqueous dispersion, preferably dry-blended. It is selected appropriately.
  • water-insoluble inorganic fine particles When water-insoluble inorganic fine particles are used as an aqueous dispersion, it may be a dispersion in an aqueous solution of a crosslinking agent, or a surfactant or a polymer dispersant may be used in an amount of 0 to 1 part by weight (for a water-absorbing resin powder). Good.
  • the ratio of the water-absorbing resin (particulate water-absorbing agent) to the water-insoluble inorganic fine particles is such that the absorption capacity under pressure (AAP) is not significantly reduced by the addition of the water-insoluble inorganic fine particles, particularly the decrease in AAP is 3.0 [g. / G], and the amount is appropriately determined, but is preferably 0 to 3 parts by weight, more preferably 2 parts by weight or less, with respect to 100 parts by weight of the water-absorbent resin (particulate water-absorbing agent).
  • Parts by weight or less are more preferred, 0.5 parts by weight or less are particularly preferred, 0.001 parts by weight or more are preferred, 0.01 parts by weight or more are more preferred, 0.05 parts by weight or more are still more preferred, 0.1 weights Part or more is particularly preferable.
  • the ratio of the water-absorbing resin (particulate water-absorbing agent) to the water-insoluble inorganic fine particles is defined based on 100 parts by weight of the water-absorbing resin (particulate water-absorbing agent). The ratio is substantially or completely the same as the ratio based on the conductive resin powder.
  • the amount of water-insoluble inorganic fine particles is less than 0.001 part by weight relative to 100 parts by weight of the water-absorbent resin (particulate water-absorbing agent), the moisture absorption fluidity is not sufficiently improved. There is a possibility that it will fall so as not to satisfy the present application.
  • the glycidyl-based crosslinking agent and the organic surface crosslinking agent that is solid at room temperature are not particularly limited, but the weight ratio is preferably in the range of 1: 1000 to 1: 1, and 1: 500 to 1: 5. Is more preferable, and a range of 1: 200 to 1:10 is even more preferable. When the above range is exceeded, the amount of the remaining epoxy compound increases, which is not preferable.
  • the glycidyl-based crosslinking agent and the organic surface crosslinking agent that is liquid at room temperature when using the organic surface crosslinking agent that is liquid at room temperature are not particularly limited, but are in a weight ratio of 1: 100.
  • a range of ⁇ 1: 0.1 is preferred, a range of 1:50 to 1: 1 is more preferred, and a range of 1:40 to 1:10 is even more preferred. If it is the said range, the amount of remaining epoxy compounds can be reduced effectively.
  • an organic surface cross-linking agent that is solid at room temperature (excluding glycidyl-based cross-linking agents) is preferably stored or mixed in a molten state.
  • an aqueous solution of the crosslinking agent can be prepared, mixing of the crosslinking agent becomes easier and more stable, and the physical properties are also stabilized.
  • methods described in Patent Documents 20 and 21 are applied.
  • heating at the time of melting may be performed continuously or in batches. Both continuous and batch operations are included in the concept of transportation and storage in the present invention.
  • the heating temperature at the time of melting is appropriately determined based on the melting point, decomposition temperature, and viscosity, but in the case of a solid at room temperature, it is usually heated beyond the melting point, and the upper limit is + 100 ° C. or lower of the melting point, further + 80 ° C. or lower, +60 It is preferable in the order of not more than ° C, not more than + 20 ° C and not more than + 10 ° C. That is, in the present invention, the non-polymeric organic compound preferably has the melting point (preferably 25 to 100 ° C.) and is heated within the range of the melting point to the melting point + 100 ° C.
  • the lower limit of the heating temperature is appropriately determined depending on the melting point, etc., but it is preferably heated to room temperature or higher, more preferably the heating temperature is 30 ° C. or higher and the melting point + 100 ° C. or lower, particularly in the range of 30 to 90 ° C. It is preferable to heat with.
  • the temperature of the aqueous surface-crosslinking agent solution is appropriately determined from the solubility of the surface-crosslinking agent used, the viscosity of the aqueous solution, and the like, but is ⁇ 10 to 100 ° C., further 5 to 50 ° C., 10 to 30 ° C., 35 to 70 ° C., A range of 40 to 65 ° C. is preferable.
  • the temperature is high, the cyclic surface cross-linking agent may be hydrolyzed (eg, decomposition from ethylene carbonate to ethylene glycol, decomposition from oxazolidinone to ethanolamine) or mixed before reacting with the water absorbent resin powder. It tends to decrease. If the temperature is too low, it may not be preferable in terms of solubility and viscosity.
  • Crosslinker containing at least one of water-absorbent resin powder, glycidyl crosslinker and organic surface crosslinker solid (melting point: 25 ° C. or more) at room temperature (excluding glycidyl crosslinker) due to reactivity and mixing property of crosslinker The temperature of the aqueous solution is preheated before mixing.
  • the aqueous crosslinking agent solution includes a glycidyl crosslinking agent and / or an organic surface crosslinking agent (excluding glycidyl crosslinking agent) that is solid at ordinary temperature (excluding glycidyl crosslinking agent), and if necessary, a third crosslinking agent and / Or an aqueous solution containing a fourth cross-linking agent, preferably an aqueous solution containing all of the cross-linking agents used for surface cross-linking.
  • the heating temperature of the aqueous solution is in the above range, and the water absorbent resin powder is preferably heated in the above range.
  • the mixing ratio of the crosslinking agent in the aqueous crosslinking agent solution is controlled by a Coriolis mass flow meter.
  • the method described in Patent Documents 20 and 21 is applied to the Coriolis type mass flow meter.
  • aqueous solution of 2-7-14 crosslinking agent Preparation of aqueous solution of 2-7-14 crosslinking agent
  • the average storage period is within 10 days, within 5 days, within 1 day, within 10 hours, within 1 hour
  • the water-absorbent resin powder it is preferable to mix and use the water-absorbent resin powder within minutes. That is, after a predetermined compound is mixed at a predetermined ratio and then brought to the above temperature, it is further mixed with the water absorbent resin powder within 10 days.
  • the temperature of the mixture is 50 ° C. or less,
  • the mixture is preferably mixed with the water absorbent resin powder within 10 days after preparation.
  • the surface crosslinking agent aqueous solution after preparing the surface crosslinking agent aqueous solution, it is preferable to store it at 50 ° C. or less, preferably 20 to 50 ° C. before mixing with the water absorbent resin powder from the viewpoint of storage stability.
  • the upper space in the storage tank at the time of storing the surface cross-linking agent aqueous solution may be air, or may be an inert gas such as nitrogen for the purpose of preventing deterioration or coloring.
  • the upper space may be reduced or pressurized as appropriate, but is usually set to normal pressure (atmospheric pressure).
  • the atmospheric dew point during storage (the dew point of the upper space) is preferably low, and is 20 ° C. or lower, more preferably 10 ° C. or lower, 0 ° C. or lower, ⁇ 10 ° C. or lower, and ⁇ 20 ° C. or lower.
  • dry air may be used during storage, or an inert gas, preferably nitrogen gas, may be used.
  • Nitrogen gas has a dew point of ⁇ 73 ° C. or lower
  • helium gas has a dew point of ⁇ 65 ° C. or lower.
  • the surface cross-linking agent aqueous solution with the water-absorbent resin powder it is preferable to measure the flow rate with a mass flow meter (preferably a Coriolis flow meter).
  • a mass flow meter preferably a Coriolis flow meter.
  • an aqueous solution of a glycidyl-based crosslinking agent and an organic surface crosslinking agent that is solid at room temperature is continuously adjusted, and within 180 seconds after the aqueous solution is adjusted. It is mixed with the water absorbent resin powder within 90 seconds and within 30 seconds.
  • an acid or a base may be used in combination with the surface crosslinking agent.
  • an organic acid or a salt thereof, an inorganic acid or a salt thereof, or an inorganic base is used, and is 0 to 10 parts by weight, more preferably 0.01 to 5 parts per 100 parts by weight of the water absorbent resin powder. It is suitably used in parts by weight, 0.1 to 3 parts by weight.
  • the organic acid used is a water-soluble organic acid having 1 to 6 carbon atoms, further 2 to 4 carbon atoms, a water-soluble saturated organic acid, particularly a saturated organic acid containing a hydroxyl group.
  • Typical organic acids are acetic acid, propionic acid, lactic acid, 3-hydroxypropionic acid, citric acid, tartaric acid and salts thereof.
  • the salt monovalent salt or polyvalent metal salt, especially alkali metal salt and / or 3 Valent salt (especially aluminum salt).
  • the inorganic acid used is carbonic acid, sulfuric acid, hydrochloric acid, phosphoric acid, polyphosphoric acid or a salt thereof, and the salt is a monovalent salt and / or a polyvalent metal salt, particularly an alkali metal salt and / or a trivalent salt. (Especially aluminum salts).
  • the inorganic base that can be used include alkali metal hydroxides, carbonates, hydrogen carbonates, and polyvalent metal hydroxides.
  • Suitable inorganic acids include aluminum sulfate, and organic acids include lactic acid.
  • the pH of the surface crosslinking agent solution is preferably an acidic solution having a pH of 2.5 to 6.9.
  • an acid (organic acid or inorganic acid) or base is used in combination with the surface crosslinking agent in the surface crosslinking step.
  • an acid (organic acid or inorganic acid) is used in combination with a cyclic dehydration-reactive surface crosslinking agent.
  • a base improves the mixing ability of the surface cross-linking agent, but may reduce the reactivity between the water-absorbent resin powder and the surface cross-linking agent, and may further decrease the stability of the surface cross-linking agent aqueous solution before surface cross-linking. .
  • caution is required because ethylene carbonate decomposes in a basic aqueous solution and produces ethylene glycol as a by-product.
  • the average time when such an acid or base, particularly a base is stored as an aqueous solution is in the above-mentioned range, particularly within 1 hour.
  • the mixing method of the water-absorbent resin powder and the surface cross-linking agent is not particularly limited.
  • the method of immersing the water-absorbent resin powder in a hydrophilic organic solvent to adsorb the surface cross-linking agent, or the surface cross-linking directly on the water-absorbent resin powder examples include a method of spraying or dropping the agent and mixing, and the latter is preferable from the viewpoint of uniformly adding a predetermined amount.
  • two or more types of surface cross-linking agents having different compositions may be added simultaneously using, for example, different spray nozzles, but a single composition is preferred from the standpoint of uniformity. If the composition is a single composition, a plurality of spray nozzles may be used in consideration of the size and processing amount of the mixing processing apparatus, the spray angle of the spray nozzle, and the like.
  • a water-absorbing resin contains an aqueous solution containing a glycidyl-based crosslinking agent, an organic surface crosslinking agent that is solid at room temperature (excluding the glycidyl-based crosslinking agent), and, if necessary, a third crosslinking agent and / or a fourth crosslinking agent. Heat it after adding it to the powder.
  • a glycidyl-based crosslinking agent, an organic surface crosslinking agent that is solid at room temperature (excluding the glycidyl-based crosslinking agent), and if necessary, a third crosslinking agent and / or a fourth crosslinking agent are respectively in separate aqueous solutions, or Then, after adding to the water absorbent resin powder as a mixed aqueous solution, heat treatment is performed.
  • the heating temperature is preferably 70 to 300 ° C., more preferably 120 to 250 ° C., further preferably 150 to 250 ° C., and further 170 to 230 ° C.
  • the heating time at the temperature is preferably The range is 1 minute to 2 hours and 5 minutes to 1 hour.
  • the cooling temperature after the surface cross-linking agent is lower than the surface cross-linking temperature, particularly 10 ° C. or higher, and is preferably 100 ° C. or lower, more preferably 30 to 90 ° C., particularly 40 to 80 ° C.
  • the water absorption capacity under pressure (AAP) described later is in the range described below, preferably 20 [g / g] or more, more preferably 20 to A 35 [g / g] water-absorbing agent can be obtained.
  • the content of ⁇ -hydroxypropionic acid (salt) in the water-absorbent resin powder before surface crosslinking is preferably 1000 ppm or less, more preferably 500 ppm or less, and even more preferably 200 ppm or less. Preferably, 100 ppm or less is particularly preferable.
  • This step is a step of adding each additive to impart various functions to the water-absorbing agent, and is composed of one or a plurality of steps.
  • the additive include a hygroscopic fluidity improver that improves the handleability of the water-absorbent resin powder under high temperature and high humidity, a liquid permeability improver that improves liquid permeability, a water absorption speed and a liquid permeability.
  • water-insoluble inorganic fine particles and / or polyvalent metal compounds can be added, and additions other than inorganic powder and / or polyvalent metal may be added simultaneously or separately.
  • the weight average molecular weight of the polyvalent cationic polymer that can be used in the present invention is preferably 1000 or more, more preferably 2000 or more, still more preferably 5000 or more, and particularly preferably 10,000 or more. Further, the number average molecular weight is preferably 2000 or more, and more preferably 5000 or more. If the weight average molecular weight is less than 1000, the expected effect may not be obtained.
  • the weight average molecular weight is measured by an equilibrium sedimentation method, and the number average molecular weight is measured by a viscosity method. In addition, it can also be measured by gel permeation chromatography, static light scattering method or the like. From the viewpoint of cost, it is sufficient that the upper limit of the weight average molecular weight is about 5 million, and further about 1 million.
  • the polyvalent cationic polymer according to the present invention has a cation density of preferably 2 [mmol / g] or more, more preferably 4 [mmol / g] or more, and further preferably 6 [mmol / g] or more.
  • the cation density is less than 2 [mmol / g]
  • the water absorbent resin aggregate after swelling in the water absorbent resin (particulate water absorbent) obtained by mixing the water absorbent resin powder and the polyvalent cationic polymer
  • an upper limit is suitably determined with a repeating unit, it is 30 [mmol / g] or less, Furthermore, it is 25 [mmol / g] or less.
  • polyvalent cationic polymer examples include polyethyleneimine.
  • polyvalent cationic polymers polyamidine or a salt thereof, polyvinylamine or a salt thereof, a polyvinylamine-poly (N-vinylformamide) copolymer or a salt thereof, poly (N-vinyl) A polyamine polymer containing at least one selected from a partial hydrolyzate of formamide) or a salt thereof, a polyvinylamine or a salt thereof, a polyamine polymer containing a partial hydrolyzate of poly (N-vinylformamide) or a salt thereof.
  • These polyvalent cationic polymers may contain other repeating units of about 0 to 30 mol%, further about 0 to 10 mol%.
  • the ratio of the water-absorbent resin powder to the polyvalent cationic polymer is appropriately determined. From the viewpoint of AAP, CRC, and hygroscopic fluidity, less than 0.3 parts by weight with respect to 100 parts by weight of the water-absorbent resin powder. 25 parts by weight or less, 0.2 parts by weight or less, particularly 0.1 parts by weight or less are preferable, and the lower limit is 0.001 parts by weight or more, and further 0.01 parts by weight or more.
  • chelating agents especially organophosphorus chelating agents and aminocarboxylic acid chelating agents
  • ⁇ -hydroxycarboxylic acids especially lactic acid (salts)
  • An anti-coloring agent or a urine resistance improving agent selected from inorganic or organic reducing agents especially sulfur-based inorganic reducing agents.
  • the water absorbent resin powder having a large surface area generally tends to be colored or deteriorated.
  • the amount of the anti-coloring agent or urine resistance improving agent used is preferably 0 to 3 parts by weight, more preferably 0.001 to 1 part by weight, and more preferably 0.05 to 0. 5 parts by weight is particularly preferred. Since these anti-coloring agents or urine resistance (weather resistance) improvers are added to monomers, hydrous gels, dry polymers, water-absorbing resin powders, etc., the addition process is appropriately determined after the polymerization process. The In addition, since the said inorganic or organic reducing agent is consumed at a superposition
  • Examples of the chelating agent include chelating agents disclosed in US Pat. Nos. 6,599,989, 6,469,080, and European Patent No. 2,163,302, particularly non-polymer chelating agents, organophosphorus chelating agents, and aminocarboxylic acid chelating agents.
  • Examples of the ⁇ -hydroxycarboxylic acid include malic acid (salt), succinic acid (salt), and lactic acid (salt) disclosed in US Patent Application Publication No. 2009/0312183.
  • Examples of the inorganic or organic reducing agent include sulfur-based reducing agents disclosed in U.S. Patent Application Publication No. 2010/0062252, and particularly sulfites and hydrogen sulfites.
  • a surfactant is used in combination with the above-mentioned surface cross-linking agent or preferably in a surface cross-linking agent aqueous solution.
  • the surfactant that can be used is not particularly limited, but the surfactants disclosed in WO 97/017397 and US Pat. No. 6,107,358, that is, nonionic surfactants, anionic surfactants, and cationic interfaces. Examples include activators and amphoteric surfactants. These surfactants may be polymerizable or reactive with acrylic acid (salt) monomers or water-absorbing resin powders.
  • the polyacrylic acid (salt) water-absorbent resin powder may contain a surfactant, and the production method of the present invention preferably includes a step of mixing the surfactant in any step.
  • a form used for controlling the cell ratio of the water-absorbent resin powder and a form used in combination with a surface cross-linking agent in the surface cross-linking step may be mentioned.
  • the water absorbent resin powder may be coated with a surfactant.
  • the surfactant may be used also during the polymerization.
  • the surfactant is further mixed with the surface cross-linking agent, particularly with the surface cross-linking agent aqueous solution simultaneously or separately, preferably simultaneously. The physical properties after surface cross-linking are also improved.
  • the type and amount of the surfactant to be used are appropriately determined, but it is preferably used within the range of the above surface tension, and is 0 to 0.5 parts by weight, more preferably 0.00001 to 0 parts by weight with respect to the water absorbent resin powder. .1 part by weight, used in the range of 0.001 to 0.05 part by weight.
  • these surfactants anionic surfactants, nonionic surfactants, or silicone surfactants are preferably used from the viewpoint of effects, and nonionic surfactants or silicone surfactants are used. More preferably.
  • the surface tension of the final water-absorbing agent after mixing the surfactant is in the above range (60, 65, 70 or more), and the type and amount of the surfactant are selected within this range.
  • a second classification step (performed after the surface crosslinking step), an evaporation monomer recovery step, a granulation step, and the like may be provided as necessary.
  • the water-absorbent resin powder may be mixed with other oxidizing agents, antioxidants, water, polyvalent metal compounds, water-insoluble inorganic fine particles such as silica and metal soap, deodorants, antibacterial agents, pulps and the like.
  • Thermoplastic fibers or the like may be added to the water-absorbent resin powder in an amount of more than 0% by weight and 3% by weight or less, preferably more than 0% by weight and 1% by weight or less.
  • (2-10) Conventional Surface Crosslinking In addition to the above Patent Documents 20 and 21, many surface crosslinking methods for water absorbent resins (water absorbent resin powders) have been proposed, and as Patent Documents 32 to 56, US Pat. No.
  • a production method is known in which a crosslinking agent (excluding glycidyl-based crosslinking agent) is used in combination, preferably further in combination with an organic surface crosslinking agent (excluding glycidyl-based crosslinking agent) that is liquid at ordinary temperature (melting point less than 25 ° C.). Absent.
  • a crosslinking agent excluding glycidyl-based crosslinking agent
  • an organic surface crosslinking agent excluding glycidyl-based crosslinking agent
  • the present application is patented by using an organic surface cross-linking agent (except glycidyl-based cross-linking agent) that is solid (melting point: 25 ° C. or higher) at room temperature with a particle size of 150 ⁇ m or more and less than 850 ⁇ m in the water-absorbent resin powder being 95 wt% or more
  • glycidyl-based cross-linking agent except glycidyl-based cross-linking agent
  • a method different from that in References 15 to 18 was used to reduce the residual amount of the glycidyl-based crosslinking agent and improve the fluidity during moisture absorption.
  • Water-absorbing agent of the present invention is a water-absorbing agent obtained by surface-crosslinking a polyacrylic acid (salt) -based water-absorbing resin powder with a glycidyl-based crosslinking agent, and has a particle diameter of 150 ⁇ m or more.
  • a particulate water absorbing agent having a particle content of less than 850 ⁇ m of 95% by weight or more, a residual glycidyl crosslinking agent of 5 ppm or less, and a moisture absorption blocking rate of 20% or less.
  • the water-absorbing agent of the present invention that satisfies the above-mentioned characteristics can reduce rash, etc., and also can reduce wet feeling after urination and urination, particularly in sanitary materials such as diapers where the water-absorbing agent is used in a high ratio. Furthermore, there is no degradation in performance when sanitary materials are stored under conditions of high temperature and humidity.
  • the water-absorbing agent of the present invention can be preferably obtained by the method for producing a water-absorbing agent described above. Accordingly, the present invention further provides a sanitary material comprising the absorbent of the present invention.
  • the water-absorbing agent of the present invention is characterized in that the content of particles of 150 ⁇ m or more and less than 850 ⁇ m is 95% by mass or more. Preferably, when the content of particles having a particle size of 150 ⁇ m or more and less than 850 ⁇ m is 97% by mass or more, the water-absorbing agent having the above-described characteristics can be obtained.
  • the upper limit of the content of particles having a particle size of 150 ⁇ m or more and less than 850 ⁇ m is 100% by weight.
  • the content of particles of 150 ⁇ m or more and less than 500 ⁇ m is 60% by mass or more, preferably 65% by mass or more, and more preferably 70% by mass or more.
  • the upper limit of the content of particles of 150 ⁇ m or more and less than 500 ⁇ m is not particularly limited, but is usually 98% by weight or less, preferably 90% by weight or less. Furthermore, the content of particles of 150 ⁇ m or more and less than 300 ⁇ m is 20% by mass or more, preferably 25% by mass or more. The upper limit of the content of particles of 150 ⁇ m or more and less than 300 ⁇ m is not particularly limited, but is usually 50% by weight or less, preferably 40% by weight or less.
  • a water-absorbing agent having the above-described characteristics can be obtained by the particle size distribution as described above.
  • the water-absorbing agent of the present invention preferably has a particle ratio of 600 to 150 ⁇ m (the standard sieve classification is 5% by weight or less of the 150 ⁇ m pass through standard sieve and / or 5% by weight or less of the 710 ⁇ m non-pass through substance). Stipulation) is 80% by weight or more.
  • the water-absorbing agent of the present invention preferably contains a polyhydric alcohol.
  • the content of the polyhydric alcohol is not particularly limited, but the polyhydric alcohol is preferably contained in an amount of 0.1 to 1% by weight or less. More preferably 0.2% by weight or more and 1% by weight or less, more preferably 0.2% by weight or more and 0.5% by weight or less, so that more characteristics (for example, water absorption magnification, water absorption magnification under pressure, A water-absorbing agent having an excellent balance) can be obtained.
  • polyhydric alcohol the above-mentioned compounds, in particular, polyhydric alcohols having 2 to 6 carbon atoms and amino alcohols, diols having 3 to 6 carbon atoms, particularly diols having 3 carbon atoms are selected.
  • the water-absorbing agent of the present invention is characterized in that it contains epoxy compound 0 (below the detection limit; hereinafter sometimes referred to as ND) to 5 ppm, and further contains 0 (ND) to 2 ppm, preferably detection limit value (ND) to 2 ppm. Therefore, the water-absorbing agent having the above-described characteristics can be obtained.
  • the water-absorbing agent of the present invention preferably has a non-pressurized water absorption capacity (CRC) of 25 g / g or more. More preferably, it is 27 g / g or more, still more preferably 30 g / g or more, and still more preferably 33 g / g or more, whereby the water-absorbing agent having the above-described characteristics can be obtained.
  • CRC non-pressurized water absorption capacity
  • the upper limit is appropriately determined, but is preferably 50 g / g or less, more preferably 45 g / g or less, and 40 g / g or less in order from the balance with other physical properties such as AAP and liquid permeability (for example, SFC and GBP).
  • the water-absorbing agent of the present invention preferably has a water absorption capacity under pressure (AAP 0.3 psi) of 20 g / g or more. More preferably, it is 24 g / g or more, still more preferably 26 g / g or more, and still more preferably 28 g / g or more. Although an upper limit is determined suitably, it is 40 g / g or less from the balance with other physical properties, such as AAP and liquid permeability (for example, SFC and GBP), Furthermore, it is about 37 g / g or less.
  • AAP water absorption capacity under pressure
  • the water absorption capacity (AAP 0.7 psi) of the water-absorbing agent of the present invention is preferably 10 g / g or more, 15 g / g or more, 20 g / g or more, 22 g / g or more, 24 g / g or more.
  • the water-absorbing agent of the present invention contains water-insoluble inorganic fine particles and / or polyvalent metal cations.
  • the water-insoluble inorganic fine particles the above-mentioned compounds are preferable, and the ratio of the water-absorbing agent to the water-insoluble inorganic fine particles is preferably 3 parts by weight or less, more preferably 2 parts by weight or less with respect to 100 parts by weight of the water-absorbing agent.
  • 0.5 part by weight or less is particularly preferable, 0.001 part by weight or more is preferable, 0.01 part by weight or more is more preferable, 0.05 part by weight or more is further preferable, 0.1 part by weight The above is particularly preferable.
  • the polyvalent metal cation is preferably 0.001 to 3 parts by weight, more preferably 0.01 to 2 parts by weight, still more preferably 0.02 to 1 part by weight with respect to 100 parts by weight of the water-absorbing agent. 0.03-0.9 parts by weight is particularly preferred, and 0.05-0.8 parts by weight is most preferred.
  • the water-absorbent resin (particulate water-absorbing agent) of the present invention is characterized by having a moisture absorption blocking rate of 20% by weight or less.
  • a moisture absorption blocking rate is prescribed
  • the particulate water-absorbing agent of the present invention is used for applications intended to absorb water, and particularly used for processed sheets and tapes.
  • the sheet-like and tape-like processed water-absorbing agent of the present invention can be used for water-absorbing articles (final consumer goods) such as water-stopping rubber, water-stopping tape, kitchen sheets, pet sheets, hemostatic sheets, and other paper diapers and napkins.
  • water-absorbing agent of the present invention is excellent in impact resistance and moisture-absorbing fluidity, it can be expected to reduce troubles in the manufacturing process of the absorbent article and improve the working environment when used in an absorbent body or absorbent article. A decrease in water absorption performance due to damage is suppressed, and the original performance of the particulate water-absorbing agent can be sufficiently exhibited in an absorbent article or the like.
  • the particulate water-absorbing agent of the present invention has high water-absorbing performance (CRC, AAP, etc.), is excellent in coloration with time, and is excellent in urine resistance as evaluated by an increase rate of deteriorated soluble matter. Therefore, since coloring with time and deterioration of water absorption performance of absorbent articles and the like can be suppressed, problems such as liquid (urine) leakage and skin damage do not occur even after processing into a sheet or tape.
  • the absorbent body and absorbent article of the present invention comprise the water-absorbing agent of the present invention, and the “absorber” here refers to an absorbent material molded mainly with a water-absorbing agent and hydrophilic fibers.
  • an absorbent body molded containing 20 to 100% by weight of a water absorbing agent and 80 to 0% by weight of hydrophilic fibers.
  • the content of the water-absorbing agent in the absorber is preferably 20 to 100% by weight, more preferably 25 to 90% by weight, and more preferably 30 to 80% by weight is more preferable, and 40 to 80% by weight is most preferable. The higher the content, the more easily the water absorption performance of the absorbent body and absorbent article is affected by the water absorption performance of the water absorbing agent.
  • JIS standard sieve JIS Z8801-1 (2000) having a mesh size of 850 ⁇ m, 710 ⁇ m, 600 ⁇ m, 500 ⁇ m, 420 ⁇ m, 300 ⁇ m, 212 ⁇ m, 150 ⁇ m, 106 ⁇ m, 45 ⁇ m or a corresponding sieve, was classified.
  • the solid content was measured as follows.
  • ND level 100 ppm or less.
  • water-absorbent resin powder water-absorbing agent
  • 5 ml of methyl alcohol was added to the beaker, and the solution was filtered from the dispersion of the water-absorbing agent using an HPLC filter attached to a syringe.
  • 1.0 g of the obtained filtrate is put into a 50 ml eggplant flask and 0.05 ml of 12 wt% nicotinamide aqueous solution is added.
  • the eggplant flask is equipped with an air-cooled tube and heated in a boiling water bath for 30 minutes so that the solution does not dry, thereby reacting nicotinamide with the remaining crosslinking agent.
  • the reaction solution was filtered using filter paper, and the filtrate was concentrated to dryness.
  • an HPLC eluent was added, and the nicotinamide-crosslinking agent adduct was analyzed by high performance liquid chromatography (HPLC) by UV absorption.
  • HPLC high performance liquid chromatography
  • a known amount of cross-linking agent was added without using the water-absorbing agent powder, and the same operation was performed.
  • the obtained calibration curve was used as an external standard, and the epoxy compound of the water-absorbing resin powder was taken into account in consideration of the dilution rate of the filtrate.
  • the content (ppm) was determined.
  • Teflon registered trademark
  • a rotor placed in a 260 ml polypropylene beaker, add 1 g of weighed water-absorbent resin powder and 100 g of a 0.9 mass% sodium chloride aqueous solution, and add swollen gel particles (about 1 mm) to a magnetic stirrer. (About 100 to 200 rpm) and stirred for 1 hour. After stirring, the supernatant was sucked with a polypropylene syringe and filtered with a chromatodisc (GL Chromatodisc 25A, manufactured by GL Sciences Inc.). The filtrate was analyzed by liquid chromatography to quantify the residual ethylene glycol content and other polyhydric alcohols.
  • GL Chromatodisc 25A manufactured by GL Sciences Inc.
  • the water-absorbent resin powder in the aluminum cup was gently transferred onto a JIS standard sieve (The IIDA TESTING SIEVE / inner diameter 80 mm) having an opening of 2000 ⁇ m (8.6 mesh), and a low-tap type sieve shaker (Iida Co., Ltd.).
  • a JIS standard sieve The IIDA TESTING SIEVE / inner diameter 80 mm
  • a low-tap type sieve shaker Iida Co., Ltd.
  • classification was performed for 5 seconds under conditions of a temperature of 20 to 25 ° C. and a relative humidity of 50% RH.
  • the weight of the water-absorbent resin powder (weight W9 [g]) remaining on the JIS standard sieve and the water-absorbent resin powder (weight W10 [g]) that passed through the JIS standard sieve were measured.
  • the fluidity (moisture absorption blocking rate) was calculated. The lower the value of the moisture absorption blocking rate, the better the moisture absorption fluidity.
  • the monomer aqueous solution (a) is charged into a reactor formed by attaching a lid to a double-arm jacketed stainless steel kneader having two sigma-type blades with an internal volume of 10 L, and the liquid temperature is set to 30. Nitrogen gas was blown into the reactor while maintaining the temperature, and nitrogen substitution was performed so that the dissolved oxygen in the system was 1 ppm or less.
  • hydrogel crosslinked polymer (a) was polymerized at 30 to 90 ° C. while pulverizing, and the hydrogel crosslinked polymer (a) was taken out of the reactor after 60 minutes from the start of polymerization.
  • the obtained hydrogel crosslinked polymer (a) had a diameter of about 5 mm.
  • the finely divided hydrogel crosslinked polymer (a) was spread on a wire mesh having an opening of 300 ⁇ m (50 mesh) and dried with hot air at 180 ° C. for 45 minutes to obtain a dried product.
  • the water content of the dried product was 3.7% by weight.
  • the dried product was pulverized with a roll mill, and further classified with JIS standard sieves having openings of 850 ⁇ m and 150 ⁇ m. By this series of operations, a water absorbent resin powder (a) was obtained.
  • the content of particles having a particle diameter of 150 ⁇ m or more and less than 850 ⁇ m in the obtained water-absorbent resin powder (a) was 97.3% by weight.
  • the weight average particle diameter (D50) of the obtained water absorbent resin powder (a) was 386 ⁇ m.
  • the water absorbent resin powder (a) had a CRC (water absorption capacity under no pressure) of 53.0 [g / g] and AAP of 9.8 [g / g].
  • the monomer aqueous solution (C) was obtained by quickly adding and mixing the solution (B) to the solution (A) stirred in step (b).
  • the aqueous monomer solution (C) rose to about 100 ° C. due to heat of neutralization and heat of dissolution.
  • the neutralization rate of acrylic acid was 73.5 mol%.
  • Polymerization started soon after the monomer aqueous solution was poured into the vat, and the polymerization reached a peak temperature within about 1 minute. After 3 minutes, the irradiation of ultraviolet rays was stopped, and the water-containing polymer was taken out. These series of operations were performed in a system open to the atmosphere.
  • the obtained water-containing polymer was pulverized with a meat chopper (MEAT-CHOPER TYPE: 12VR-400KSOX Iizuka Kogyo Co., Ltd., die hole diameter: 6.4 mm, hole number: 38, die thickness 8 mm). Hydrous polymer particles were obtained. The obtained pulverized water-containing polymer particles were finely divided (subdivided) to 2 mm or less.
  • the finely divided pulverized hydrous polymer particles were spread on a 50 mesh (mesh opening 300 ⁇ m) wire net and dried with hot air at 180 ° C. for 45 minutes to obtain a dried product.
  • the water content of the dried product was 3.8% by weight.
  • the dried product is pulverized using a roll mill, and further classified with a JIS standard sieve having an opening of 850 ⁇ m and an opening of 150 ⁇ m, thereby forming a water-absorbing resin that is an irregularly crushed water-absorbing resin (solid content of 96% by weight).
  • Resin powder (b) was obtained.
  • the content of particles having a particle diameter of 150 ⁇ m or more and less than 850 ⁇ m in the obtained water absorbent resin powder (b) was 97.1% by weight.
  • the weight average particle diameter (D50) of the obtained water absorbent resin powder (b) was 435 ⁇ m.
  • the water absorbent resin powder (b) had a CRC (water absorption capacity under no pressure) of 47.3 [g / g] and AAP of 9.8 [g / g].
  • Table 1 shows properties of the water absorbent resin powder (a) described in Production Example 1 as a comparative water absorbent resin (1).
  • Table 1 shows properties of the water absorbent resin powder (b) described in Production Example 2 as a comparative water absorbent resin (2).
  • Example 1 With respect to 100 parts by weight of the water-absorbent resin powder (a) described in Production Example 1, 0.03 part by weight of ethylene glycol diglycidyl ether (trade name Denacol EX-810, manufactured by Nagase Chemtech) was heated to 45 ° C. in advance. A surface treatment agent consisting of 1.0 part by weight of ethylene carbonate (melting point: 36 ° C.) and 3.0 parts by weight of water was uniformly mixed to prepare an aqueous solution of the crosslinking agent. Was mixed with the water-absorbent resin powder in about 10 seconds and heat-treated at 175 ° C. for 40 minutes. The water absorbent resin powder and the aqueous crosslinking agent solution were heated to 45 ° C.
  • ethylene glycol diglycidyl ether trade name Denacol EX-810, manufactured by Nagase Chemtech
  • Water absorbent resin powder (1) was obtained by adding 0.3 part by weight of fumed silica AEROSIL200 manufactured by Nippon Aerosil Co., Ltd. to 100 parts by weight of water absorbent resin powder (a-1) and mixing them uniformly. Table 1 shows properties of the water absorbent resin powder (1).
  • Example 2 0.025 parts by weight of ethylene glycol diglycidyl ether, 0.3 parts by weight of ethylene carbonate previously heated to 45 ° C., 100 parts by weight of the water-absorbent resin powder (b) described in Production Example 2, A surface treatment agent (3 components) consisting of 0.5 parts by weight of 2-propanediol (propylene glycol) (melting point -59 ° C.) and 3.0 parts by weight of water was uniformly mixed to prepare an aqueous crosslinking agent solution. About 10 seconds after preparing the aqueous crosslinking agent solution, the mixture was mixed with the water-absorbent resin powder and heat-treated at 175 ° C. for 40 minutes.
  • a surface treatment agent consisting of 0.5 parts by weight of 2-propanediol (propylene glycol) (melting point -59 ° C.) and 3.0 parts by weight of water was uniformly mixed to prepare an aqueous crosslinking agent solution. About 10 seconds after preparing the aqueous
  • the temperature of the aqueous solution of the surface cross-linking agent at the time of mixing (before the heat treatment) was 45 ° C. Thereafter, the mixture was passed through a JIS standard sieve having an opening of 850 ⁇ m to obtain a water absorbent resin powder (b-2).
  • Table 1 shows properties of the water absorbent resin powder (2).
  • Example 3 100 parts by weight of the water-absorbent resin powder (b-2) described in Example 2 was mixed with a 50 wt% aqueous aluminum sulfate solution (8 wt% as the aluminum oxide content) as the fourth cross-linking agent (polyvalent metal cation; inorganic ionic cross-linking agent). %) was added and mixed uniformly to obtain a water absorbent resin powder (3).
  • Table 1 shows properties of the water absorbent resin powder (3).
  • a comparative water-absorbent resin powder (3) was obtained by adding 0.3 parts by weight of fumed silica AEROSIL200 manufactured by Nippon Aerosil Co., Ltd. to 100 parts by weight of the water-absorbent resin powder (a) described in Production Example 1 and mixing them uniformly. .
  • Table 1 shows properties of the water absorbent resin powder (3).
  • a surface treatment agent consisting of 0.03 parts by weight of ethylene glycol diglycidyl ether and 3.0 parts by weight of water is uniformly mixed with 100 parts by weight of the water-absorbent resin powder (a) described in Production Example 1 at 175 ° C. Heat-treated for 40 minutes. Thereafter, the mixture was passed through a JIS standard sieve having an opening of 850 ⁇ m to obtain a water absorbent resin powder (aC-4).
  • a comparative water absorbent resin powder (4) was obtained by adding 0.3 part by weight of fumed silica AEROSIL200 manufactured by Nippon Aerosil Co., Ltd. to 100 parts by weight of the water absorbent resin powder (aC-4) and mixing them uniformly. Table 1 shows properties of the comparative water absorbent resin powder (4).
  • Comparative Example 5 A surface treatment agent consisting of 1.0 part by weight of ethylene carbonate and 3.0 parts by weight of water is uniformly mixed with 100 parts by weight of the water-absorbent resin powder (b) described in Production Example 2, and heated at 175 ° C. for 40 minutes. Processed. Thereafter, the mixture was passed through a JIS standard sieve having an opening of 850 ⁇ m to obtain a water absorbent resin powder (a-C-5). Comparative water absorbent resin powder (5) is obtained by adding 1.0 part by weight of 50% aqueous solution of aluminum sulfate (8% as aluminum oxide) to 100 parts by weight of water absorbent resin powder (aC-5) and mixing them uniformly. It was. Table 1 shows properties of the comparative water absorbent resin powder (5).
  • N, N′-methylenebisacrylamide as a cross-linking agent was dissolved in 5500 g of an aqueous solution of sodium acrylate having a neutralization rate of 75 mol% (monomer concentration: 33%), and nitrogen gas was used for 30 minutes. After degassing, supply the reactor to a jacketed stainless steel double-armed kneader with an internal volume of 10L and two sigma-type blades, and keep the monomer at a temperature of 30 ° C to further replace the reaction system with nitrogen did.
  • the resulting hydrogel polymer fine-grained product was spread on a 50 mesh wire net and dried with hot air at 150 ° C. for 90 minutes.
  • the dried product was pulverized using a vibration mill, further classified with 20 mesh, and a water-absorbent resin powder (C6) as a base polymer having an irregular crushed shape and an average particle diameter of 400 ⁇ m was obtained.
  • Comparative water-absorbent resin powder (7) was obtained by adding 0.3 part by weight of fumed silica AEROSIL200 manufactured by Nippon Aerosil Co., Ltd. to 100 parts by weight of comparative water-absorbent resin (7) and mixing uniformly.
  • Table 1 shows properties of the comparative water absorbent resin powder (7).
  • Examples 1 to 3 which are the present invention, it can be seen that water-absorbent resin powders having high physical properties of CRC, AAP and moisture absorption blocking ratio and low contents of epoxy compound and polyhydric alcohol are obtained.

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Abstract

Cette invention concerne une composition absorbant l'eau qui est appropriée pour réduire les composés époxy résiduels (en particulier les agents de réticulation glycidyliques) et pour être utilisée dans les articles absorbants et les articles hygiéniques minces comportant une résine absorbant l'eau, ladite composition absorbant l'eau étant extrêmement sûre tout en démontrant un facteur d'absorption d'eau exceptionnel, un facteur d'absorption d'eau sous pression, et d'autres propriétés. L'invention concerne également un procédé permettant de fabriquer ladite composition absorbant l'eau. L'invention concerne un procédé de fabrication d'un absorbant d'eau sous forme de particules où une résine en poudre absorbant l'eau à base d'un (sel d')acide polyacrylique est réticulée en surface avec un agent de réticulation glycidylique, la quantité des particules d'un diamètre de 150 μm à moins de 850 μm dans la résine en poudre absorbant l'eau n'est pas inférieure à 95 % en poids, et un agent organique de réticulation en surface (à l'exclusion de l'agent de réticulation glycidylique) qui est solide (point de fusion : 25 °C ou plus) à température ambiante est également utilisé.
PCT/JP2013/070776 2012-08-01 2013-07-31 Absorbant d'eau utilisant une résine en poudre absorbant l'eau à base d'un (sel d')acide polyacrylique et procédé de fabrication d'un absorbant d'eau WO2014021388A1 (fr)

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WO2015129917A1 (fr) * 2014-02-28 2015-09-03 株式会社日本触媒 Absorbant particulaire à base de poly(acide (méth)acrylique) ou de poly(sel d'acide (méth)acrylique) et son procédé de fabrication
WO2015152299A1 (fr) * 2014-03-31 2015-10-08 株式会社日本触媒 Agent absorbant l'eau particulaire et son procédé de fabrication
WO2016143736A1 (fr) * 2015-03-10 2016-09-15 Ｓｄｐグローバル株式会社 Procédé de production de particules de résine absorbant les liquides aqueux, particules de résine absorbant les liquides aqueux, absorbant, et article absorbant
WO2016143739A1 (fr) * 2015-03-10 2016-09-15 Ｓｄｐグローバル株式会社 Procédé de production de particules de résine absorbant des liquides aqueux, et corps absorbant et article absorbant
JP2017185485A (ja) * 2016-03-31 2017-10-12 株式会社日本触媒 吸水剤及びその製造方法
JPWO2017169246A1 (ja) * 2016-03-31 2019-02-28 住友精化株式会社 吸水性樹脂粒子の製造装置
KR101989570B1 (ko) * 2018-10-23 2019-09-24 김명환 항균 및 소취 효과가 있는 기능성 요실금 팬티의 제조방법
WO2020122390A1 (fr) 2018-12-12 2020-06-18 주식회사 엘지화학 Polymère superabsorbant et son procédé de préparation
JP2021517606A (ja) * 2018-11-13 2021-07-26 エルジー・ケム・リミテッド 高吸水性樹脂の製造方法
JP2021517927A (ja) * 2018-12-12 2021-07-29 エルジー・ケム・リミテッド 高吸水性樹脂およびその製造方法
JP2022524520A (ja) * 2019-09-30 2022-05-06 エルジー・ケム・リミテッド 高吸水性樹脂の製造方法
US11358121B2 (en) 2016-12-23 2022-06-14 Lg Chem, Ltd. Super absorbent polymer and method for producing same
US11931290B2 (en) 2017-12-21 2024-03-19 Nippon Shokubai Co., Ltd. Water absorbent resin powder for heat-generating element composition, and heat-generating element composition

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US10207250B2 (en) 2014-02-28 2019-02-19 Nippon Shokubai Co., Ltd. Poly(meth)acrylic acid (salt)-based particulate absorbent
CN106029220A (zh) * 2014-02-28 2016-10-12 株式会社日本触媒 聚(甲基)丙烯酸(盐)系颗粒状吸水剂和制造方法
WO2015129917A1 (fr) * 2014-02-28 2015-09-03 株式会社日本触媒 Absorbant particulaire à base de poly(acide (méth)acrylique) ou de poly(sel d'acide (méth)acrylique) et son procédé de fabrication
JPWO2015129917A1 (ja) * 2014-02-28 2017-03-30 株式会社日本触媒 ポリ（メタ）アクリル酸（塩）系粒子状吸水剤及び製造方法
KR102378113B1 (ko) * 2014-03-31 2022-03-25 가부시키가이샤 닛폰 쇼쿠바이 입자상 흡수제 및 그의 제조 방법
CN106132534A (zh) * 2014-03-31 2016-11-16 株式会社日本触媒 颗粒状吸水剂及其制造方法
KR20160140659A (ko) * 2014-03-31 2016-12-07 가부시키가이샤 닛폰 쇼쿠바이 입자상 흡수제 및 그의 제조 방법
CN106132534B (zh) * 2014-03-31 2020-06-19 株式会社日本触媒 颗粒状吸水剂及其制造方法
JPWO2015152299A1 (ja) * 2014-03-31 2017-04-13 株式会社日本触媒 粒子状吸水剤及びその製造方法
US20170136441A1 (en) * 2014-03-31 2017-05-18 Nippon Shokubai Co., Ltd. Particulate water-absorbing agent and method for producing the same
US10363544B2 (en) 2014-03-31 2019-07-30 Nippon Shokubai Co., Ltd. Particulate water-absorbing agent
WO2015152299A1 (fr) * 2014-03-31 2015-10-08 株式会社日本触媒 Agent absorbant l'eau particulaire et son procédé de fabrication
JPWO2016143736A1 (ja) * 2015-03-10 2018-01-25 Ｓｄｐグローバル株式会社 水性液体吸収性樹脂粒子の製造方法、水性液体吸収性樹脂粒子、吸収体及び吸収性物品
EP3269757A4 (fr) * 2015-03-10 2019-01-16 SDP Global Co., Ltd. Procédé de production de particules de résine absorbant les liquides aqueux, particules de résine absorbant les liquides aqueux, absorbant, et article absorbant
WO2016143736A1 (fr) * 2015-03-10 2016-09-15 Ｓｄｐグローバル株式会社 Procédé de production de particules de résine absorbant les liquides aqueux, particules de résine absorbant les liquides aqueux, absorbant, et article absorbant
JPWO2016143739A1 (ja) * 2015-03-10 2017-12-21 Ｓｄｐグローバル株式会社 水性液体吸収性樹脂粒子の製造方法並びに吸収体及び吸収性物品
WO2016143739A1 (fr) * 2015-03-10 2016-09-15 Ｓｄｐグローバル株式会社 Procédé de production de particules de résine absorbant des liquides aqueux, et corps absorbant et article absorbant
JP2017185485A (ja) * 2016-03-31 2017-10-12 株式会社日本触媒 吸水剤及びその製造方法
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US12053757B2 (en) 2016-12-23 2024-08-06 Lg Chem, Ltd. Super absorbent polymer and method for producing same
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KR101989570B1 (ko) * 2018-10-23 2019-09-24 김명환 항균 및 소취 효과가 있는 기능성 요실금 팬티의 제조방법
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JP2021517927A (ja) * 2018-12-12 2021-07-29 エルジー・ケム・リミテッド 高吸水性樹脂およびその製造方法
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