WO2013125279A1 - Procédé de production de particules de résine absorbant l'eau - Google Patents

Procédé de production de particules de résine absorbant l'eau Download PDF

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Publication number
WO2013125279A1
WO2013125279A1 PCT/JP2013/051206 JP2013051206W WO2013125279A1 WO 2013125279 A1 WO2013125279 A1 WO 2013125279A1 JP 2013051206 W JP2013051206 W JP 2013051206W WO 2013125279 A1 WO2013125279 A1 WO 2013125279A1
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Prior art keywords
water
resin particles
ethylenically unsaturated
unsaturated monomer
soluble ethylenically
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PCT/JP2013/051206
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English (en)
Japanese (ja)
Inventor
裕一 小野田
健二 谷村
昌良 半田
上田　耕士
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住友精化株式会社
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Priority to JP2014500620A priority Critical patent/JP6063440B2/ja
Publication of WO2013125279A1 publication Critical patent/WO2013125279A1/fr

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    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F20/00—Homopolymers and 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 a salt, anhydride, ester, amide, imide or nitrile thereof
    • C08F20/02—Monocarboxylic acids having less than ten carbon atoms, Derivatives thereof
    • C08F20/04—Acids, Metal salts or ammonium salts thereof
    • C08F20/06—Acrylic acid; Methacrylic acid; Metal salts or ammonium salts thereof
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F2/00—Processes of polymerisation
    • C08F2/12—Polymerisation in non-solvents
    • C08F2/16—Aqueous medium
    • C08F2/22—Emulsion polymerisation
    • C08F2/24—Emulsion polymerisation with the aid of emulsifying agents
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F2/00—Processes of polymerisation
    • C08F2/32—Polymerisation in water-in-oil emulsions

Definitions

  • the present invention relates to a method for producing water-absorbing resin particles.
  • Water-absorbent resin particles have been used in applications such as sanitary materials such as disposable diapers and sanitary products, agricultural and horticultural materials such as water retention materials and soil improvement materials, industrial materials such as water-stopping materials for cables and anti-condensation materials.
  • animal excrement treatment materials such as pet sheets, dog or cat toilet compositions, simple toilets, fragrances, meat drip absorption sheets, formulations for moisturizing cosmetics, etc.
  • water absorbent resin particles The field where is applied is expanding further.
  • the water-absorbent resin particles used for such applications are required to have, for example, a high water absorption amount, an excellent water absorption rate, and an appropriate particle size according to the application.
  • Patent Document 1 a method of crosslinking the vicinity of the surface of a porous resin obtained in the presence of a foaming agent (see Patent Document 1) has been proposed.
  • the water-absorbent resin particles disclosed in Patent Document 1 were not satisfactory in terms of both the performance of the particle diameter and the water absorption speed.
  • the water-absorbent resin particles disclosed in Patent Documents 2 and 3 have a relatively large particle diameter and excellent handling properties and water absorption speed
  • the hydrocarbon dispersion medium used at the time of manufacture is contained inside the resin particles as a volatile component.
  • an odor may be generated after water absorption, and the odor when using the product may impair the comfort of the user (wearer, etc.).
  • a small amount of residual volatile components is required.
  • an object of the present invention is to provide a method that makes it possible to produce water-absorbing resin particles that have excellent handling properties and a sufficiently high water absorption rate and that have a small amount of residual volatile components.
  • the present invention relates to the following method for producing water absorbent resin particles.
  • Item 1 An aqueous liquid containing water and a water-soluble ethylenically unsaturated monomer dissolved in the water is suspended in an oily liquid containing a surfactant having a HLB of 6 or more and a hydrocarbon dispersion medium.
  • Preparing a polymerization step comprising polymerizing the water-soluble ethylenically unsaturated monomer while supplying an inert gas into the suspension,
  • a water absorption ratio represented by a ratio of a volume of the inert gas supplied per minute to a total volume of the aqueous liquid and the hydrocarbon dispersion medium is 0.1 to 3.0.
  • a method for producing resin particles is 0.1 to 3.0.
  • Item 2 An aqueous liquid containing water and a water-soluble ethylenically unsaturated monomer dissolved in the water is suspended in an oily liquid containing a surfactant having a HLB of 6 or more and a hydrocarbon dispersion medium.
  • Preparing a first polymerization step comprising polymerizing the water-soluble ethylenically unsaturated monomer while supplying an inert gas into the suspension; After the first polymerization step, water and an additional water-soluble ethylenically unsaturated monomer dissolved in the water, which are separate from the aqueous liquid already introduced into the suspension An aqueous liquid is added to the reaction mixture after polymerization to suspend it, and then the water-soluble ethylenically unsaturated monomer is polymerized once while supplying an inert gas into the suspension.
  • n is an integer of 1 or more.
  • the method for producing water-absorbing resin particles wherein the gas supply ratio in the n-th polymerization step, expressed by the ratio of the inert gas, is 0.1 to 3.0.
  • Item 3 The method for producing water-absorbent resin particles according to Item 1 or 2, wherein the surfactant comprises at least one selected from the group consisting of sorbitan fatty acid ester, polyglycerin fatty acid ester, and sucrose fatty acid ester.
  • Item 4. The water-absorbing property according to any one of Items 1 to 3, wherein the water-soluble ethylenically unsaturated monomer includes at least one selected from the group consisting of acrylic acid and salts thereof, methacrylic acid and salts thereof, and acrylamide. A method for producing resin particles.
  • Item 5 The item according to any one of Items 1 to 4, wherein the hydrocarbon dispersion medium contains at least one selected from the group consisting of aliphatic hydrocarbons having 6 to 8 carbon atoms and alicyclic hydrocarbons having 6 to 8 carbon atoms. Of producing water-absorbent resin particles.
  • the water absorbent resin particles obtained by the production method of the present invention have an excellent water absorption rate. Moreover, since the water-absorbent resin particles obtained by this method have an appropriate particle size, they are excellent in handling properties. Furthermore, since the amount of residual volatile components is small, problems such as odor after water absorption can be reduced.
  • an aqueous liquid containing water and a water-soluble ethylenically unsaturated monomer dissolved in the water is converted into an oily liquid containing a surfactant having a HLB of 6 or more and a hydrocarbon dispersion medium.
  • a polymerization step comprising polymerizing a water-soluble ethylenically unsaturated monomer while suspending in the suspension to prepare a suspension and supplying an inert gas into the suspension.
  • the water-soluble ethylenically unsaturated monomer is polymerized by reverse phase suspension polymerization.
  • water-soluble ethylenically unsaturated monomer examples include ethylenically unsaturated monomers containing at least one functional group selected from the group consisting of a carboxyl group, a sulfo group, an amide group, an amino group, and the like. .
  • water-soluble ethylenically unsaturated monomer examples include (meth) acrylic acid (hereinafter referred to as “(meth) acryl” together with “acryl” and “methacryl”) and salts thereof (alkali salts), 2- (meth) acrylamide-2-methylpropanesulfonic acid and its salts (alkali salts), (meth) acrylamide, N, N-dimethyl (meth) acrylamide, 2-hydroxyethyl (meth) acrylate, N-methylol (meta ) Acrylamide, polyethylene glycol mono (meth) acrylate, N, N-diethylaminoethyl (meth) acrylate, N, N-diethylaminopropyl (meth) acrylate, and diethylaminopropyl (meth) acrylamide.
  • the amino group may be quaternized.
  • the functional group such as a carboxyl group and an amino group of the monomer can function as a functional group that can be crosslinked in a post-crosslinking step described later.
  • These water-soluble ethylenically unsaturated monomers may be used individually by 1 type, and may be used in combination of 2 or more type.
  • the water-soluble ethylenically unsaturated monomer is composed of acrylic acid and its salt, methacrylic acid and its salt, acrylamide, methacrylamide and N, N-dimethylacrylamide. It may be at least one compound selected from the group, or at least one compound selected from the group consisting of acrylic acid and its salt, methacrylic acid and its salt, and acrylamide. Furthermore, from the viewpoint of further safety, the water-soluble ethylenically unsaturated monomer may be at least one compound selected from the group consisting of acrylic acid and its salt, and methacrylic acid and its salt. .
  • the water-soluble ethylenically unsaturated monomer is introduced into the oily liquid (O) in the state of an aqueous liquid (W) dissolved in an aqueous solvent containing water.
  • the concentration of the water-soluble ethylenically unsaturated monomer in this aqueous liquid may be in the range of 20% by mass to the saturated concentration.
  • the water-soluble ethylenically unsaturated monomer The concentration may be 25-50% by weight, 30-45% by weight, or 35-42% by weight.
  • the acid group is an alkaline medium such as an alkali metal salt.
  • the salt may be formed by neutralization with a hydrating agent.
  • the alkaline neutralizer include aqueous solutions such as sodium hydroxide, potassium hydroxide and ammonia. These alkaline neutralizers may be used alone or in combination of two or more.
  • the degree of neutralization with respect to all acid groups by the alkaline neutralizer increases the osmotic pressure of the resulting water-absorbent resin particles, thereby increasing the swelling capacity, and suppressing the remaining of the excess alkaline neutralizer to improve safety, etc. From the viewpoint of preventing the problem from occurring, it may be 10 to 100 mol%, 30 to 90 mol%, 50 to 80 mol%, or 60 to 78 mol%.
  • the aqueous liquid containing a water-soluble ethylenically unsaturated monomer may contain a radical polymerization initiator.
  • This radical polymerization initiator may be water-soluble.
  • the radical polymerization initiator include persulfates such as potassium persulfate, ammonium persulfate, and sodium persulfate; methyl ethyl ketone peroxide, methyl isobutyl ketone peroxide, di-t-butyl peroxide, t-butyl cumyl peroxide , Peroxides such as t-butylperoxyacetate, t-butylperoxyisobutyrate, t-butylperoxypivalate, and hydrogen peroxide; and 2,2′-azobis (2-methylpropionamidine) 2 Hydrochloride, 2,2′-azobis [2- (N-phenylamidino) propane] dihydrochloride, 2,2′-azobis [2- (N-allyla
  • the amount of radical polymerization initiator used is usually 0.005 to 1 mol with respect to 100 mol of the water-soluble ethylenically unsaturated monomer.
  • the amount of the radical polymerization initiator used is 0.005 mol or more, the polymerization reaction does not require a long time and is efficient.
  • the amount of the radical polymerization initiator used is 1 mol or less, there is a tendency that a rapid polymerization reaction does not occur.
  • the radical polymerization initiator can also be used as a redox polymerization initiator in combination with a reducing agent such as sodium sulfite, sodium hydrogen sulfite, ferrous sulfate and L-ascorbic acid.
  • a reducing agent such as sodium sulfite, sodium hydrogen sulfite, ferrous sulfate and L-ascorbic acid.
  • the aqueous liquid containing the water-soluble ethylenically unsaturated monomer may contain a chain transfer agent in order to control the water absorption performance of the water absorbent resin particles.
  • a chain transfer agent include hypophosphite, thiol, thiolic acid, secondary alcohol, and amine.
  • An aqueous liquid containing a water-soluble ethylenically unsaturated monomer can also contain a water-soluble thickener.
  • the water-soluble thickener include hydroxyalkyl celluloses such as hydroxyethyl cellulose (HEC) and hydroxypropyl cellulose (HPC); hydroxyalkylalkyl celluloses such as hydroxyethyl methyl cellulose, hydroxypropyl methyl cellulose and hydroxyethyl ethyl cellulose; carboxymethyl cellulose and the like Carboxyalkylcellulose; Carboxyalkylhydroxyalkylcellulose such as carboxymethylhydroxyethylcellulose.
  • the water-soluble thickener may be at least one compound selected from hydroxyalkylcellulose, hydroxyalkylalkylcellulose and carboxyalkylhydroxyalkylcellulose, and at least one selected from hydroxyethylcellulose and hydroxypropylcellulose. It may be a seed compound. Hydroxyethyl cellulose and hydroxypropyl cellulose have high solubility in an aqueous liquid, can easily develop the thickening effect of the aqueous liquid, and can further reduce the amount of residual volatile components of the water-absorbent resin particles.
  • the aqueous liquid containing a water-soluble ethylenically unsaturated monomer may contain a hydrophilic polymer dispersant.
  • the hydrophilic polymer dispersant include polyvinyl alcohol (PVA), polyvinyl pyrrolidone (PVP), polyethylene glycol (PEG), polypropylene glycol, polyethylene glycol / polypropylene glycol block copolymer, polyglycerin, polyoxyethylene glycerin, Examples thereof include polyoxypropylene glycerin, polyoxyethylene / polyoxypropylene glycerin copolymer, and polyoxyethylene sorbitan fatty acid ester.
  • PVA polyvinyl alcohol
  • PVP polyvinyl pyrrolidone
  • PEG polyethylene glycol
  • PEG polypropylene glycol
  • polyethylene glycol / polypropylene glycol block copolymer polyglycerin
  • polyoxyethylene glycerin examples thereof include polyoxypropylene g
  • the hydrophilic polymer dispersant may be at least one compound selected from the group consisting of polyvinyl alcohol, polyvinyl pyrrolidone, polyethylene glycol, polypropylene glycol and polyglycerin, and the effect of reducing the amount of residual volatile components From the viewpoint, polyvinyl pyrrolidone or polyvinyl alcohol may be used.
  • These hydrophilic polymer dispersants may be used alone or in combination of two or more.
  • the oily liquid used in the present embodiment includes a surfactant having an HLB of 6 or more and a hydrocarbon dispersion medium.
  • the HLB of the surfactant may be 6 to 16, 7 to 16, 8 to 12, or 8.5 to 10.5.
  • the state of W / O type reverse phase suspension becomes better, and particles having a more preferable particle diameter and a better water absorption rate tend to be obtained. .
  • surfactant examples include sorbitan fatty acid ester, (poly) glycerin fatty acid ester (“(poly)” means both with and without the prefix “poly”; the same applies hereinafter), Sugar fatty acid ester, polyoxyethylene sorbitan fatty acid ester, polyoxyethylene glycerin fatty acid ester, sorbitol fatty acid ester, polyoxyethylene sorbitol fatty acid ester, polyoxyethylene alkyl ether, polyoxyethylene alkyl phenyl ether, polyoxyethylene castor oil, polyoxy Ethylene hydrogenated castor oil, alkylallyl formaldehyde condensed polyoxyethylene ether, polyoxyethylene polyoxypropylene block copolymer, polyoxyethylene polyoxypropyl alkyl ether And nonionic surfactants such as polyethylene glycol fatty acid esters; fatty acid salts, alkylbenzene sulfonates, alkylmethyl taurates, polyoxyethylene alkyl
  • sorbitan fatty acid ester and polyglycerin are preferable from the viewpoint that W / O type reverse phase suspension is good, water-absorbing resin particles are easily obtained with a suitable particle size, and are easily available industrially. At least one compound selected from the group consisting of fatty acid esters and sucrose fatty acid esters can be used. Furthermore, sorbitan fatty acid ester can be used from a viewpoint that the said various performance of the water absorbent resin particle obtained improves. These surfactants may be used alone or in combination of two or more.
  • the amount of the surfactant used is an aqueous solvent, a water-soluble ethylenic solvent, from the viewpoint of stabilizing the state of the W / O type reverse phase suspension and selecting an effective amount that can provide a suspension stabilizing effect. 0.1-5 parts by mass, 0.2-3 parts by mass, or 0.4-2 parts by mass with respect to 100 parts by mass in total of various additives such as saturated monomers, radical polymerization initiators and chain transfer agents Part.
  • the oily liquid may further contain a hydrophobic polymer dispersant.
  • a surfactant and a hydrophobic polymer dispersant in combination, the state of W / O type reverse phase suspension can be further stabilized.
  • hydrophobic polymer dispersant examples include maleic anhydride-modified polyethylene, maleic anhydride-modified polypropylene, maleic anhydride-modified ethylene / propylene copolymer, maleic anhydride-modified EPDM (ethylene-propylene-diene-terpolymer), Maleic anhydride modified polybutadiene, ethylene-maleic anhydride copolymer, ethylene-propylene-maleic anhydride copolymer, butadiene-maleic anhydride copolymer, oxidized polyethylene, ethylene-acrylic acid copolymer, ethyl cellulose, and Ethyl hydroxyethyl cellulose is mentioned.
  • the hydrophobic polymer dispersion medium includes maleic anhydride-modified polyethylene, maleic anhydride-modified polypropylene, maleic anhydride-modified ethylene-propylene copolymer, Oxidized polyethylene or ethylene-acrylic acid copolymer may be used.
  • These hydrophobic polymer dispersants may be used alone or in combination of two or more.
  • the amount of the hydrophobic polymer dispersant used is 0.1 to 5 parts by weight, 0 parts per 100 parts by weight in total of the aqueous solvent, the water-soluble ethylenically unsaturated monomer, the radical polymerization initiator and various additives. It may be 2 to 3 parts by mass, or 0.4 to 2 parts by mass.
  • hydrocarbon dispersion medium examples include chain aliphatic carbonization such as n-hexane, n-heptane, 2-methylhexane, 3-methylhexane, 2,3-dimethylpentane, 3-ethylpentane, and n-octane.
  • hydrocarbon dispersion media may be used alone or in combination of two or more.
  • hydrocarbon dispersion media may contain at least one compound selected from the group consisting of chain aliphatic hydrocarbons having 6 to 8 carbon atoms and alicyclic hydrocarbons having 6 to 8 carbon atoms. .
  • the hydrocarbon dispersion medium may contain n-heptane and cyclohexane. From the same point of view, as the mixture of the hydrocarbon dispersion medium, for example, commercially available Exol heptane (exxon mobile company: containing n-heptane and 75 to 85% isomer hydrocarbon) is used. it can.
  • Exol heptane exxon mobile company: containing n-heptane and 75 to 85% isomer hydrocarbon
  • the amount of the hydrocarbon dispersion medium used is 50 with respect to 100 parts by mass of the water-soluble ethylenically unsaturated monomer contained in the aqueous liquid from the viewpoint of appropriately removing the heat of polymerization and easily controlling the polymerization temperature. It may be ⁇ 650 parts by mass, 70 to 550 parts by mass, or 100 to 450 parts by mass. When the amount of the hydrocarbon dispersion medium used is 50 parts by mass or more, the polymerization temperature tends to be easily controlled. When the amount of the hydrocarbon dispersion medium used is 650 parts by mass or less, the productivity of polymerization tends to be improved, which is economical.
  • the gas supply ratio may be 0.12 to 2.5, 0.15 to 2.0, 0.18 to 1.5, or 0.2 to 1.2. By setting the gas supply ratio within the above range, it is possible to efficiently reduce the remaining volatile components.
  • the method according to the present embodiment solves the novel problem of reducing the amount of residual volatile components by setting the gas supply ratio to a specific range different from less than 0.1 which has been conventionally performed. .
  • the mechanism is not necessarily clear, but it is presumed as follows.
  • the main factor for the increase in residual volatile components is considered to be inclusion of hydrocarbon dispersion medium in monomer droplets by O / W / O type emulsification.
  • the polymerization proceeds while the O / W / O emulsified fine droplets in the vicinity of the surface of the droplets are appropriately replaced with bubbles, and it is assumed that the residual volatile components are reduced.
  • the inert gas controls the polymerization at least from the start of the polymerization of the monomer until the formation of the water-insoluble hydrous gel is completed.
  • the mixing of the aqueous liquid containing the monomer and the oily liquid containing the hydrocarbon solvent is from the start of energy supply related to the initiation of polymerization such as heat and light to the arrival of the exothermic peak due to the polymerization.
  • the gas may be supplied at the specific gas supply rate from the completion time to the end of the polymerization.
  • the inert gas used in the present embodiment is not particularly limited.
  • the inert gas may include nitrogen, argon, or both.
  • nitrogen can be selected from the viewpoint of industrial availability and cost.
  • the temperature of the oily liquid before forming a suspension with the aqueous liquid may be 40 ° C. or higher, 45 to 110 ° C., 50 to 100 ° C., 55 to 90 ° C., or 60 to 85 ° C.
  • the temperature of the suspension between the start of mixing the hydrocarbon dispersion medium and the aqueous liquid containing the water-soluble ethylenically unsaturated monomer until the mixing of all of these is 35 ° C. or higher, 40-100 ° C. , 45-90 ° C, 50-85 ° C, or 55-85 ° C. When the temperature of the suspension in the mixing process is within these ranges, the remaining volatile components can be more effectively reduced.
  • the polymerization temperature at the time of reverse phase suspension polymerization varies depending on the type of water-soluble radical polymerization initiator to be used, and thus cannot be generally determined.
  • the reaction temperature is 20 to 110 ° C. or 40 to 90 from the viewpoint of shortening the polymerization time by allowing the polymerization to proceed rapidly, removing the heat of polymerization, and performing the reaction smoothly. It may be ° C.
  • the polymerization time is usually 0.5 to 4 hours.
  • a water-soluble ethylenically unsaturated monomer is polymerized to produce a particulate hydrogel polymer.
  • the obtained polymer can be obtained in various forms such as a spherical shape, a granular shape, a crushed shape, a confetti shape, and an aggregate thereof.
  • the hydrogel polymer may be in the form of granules, or in the form of granules having many protrusions on the surface.
  • the reaction mixture After forming the hydrogel polymer by the first polymerization step (reverse phase suspension polymerization) as described above, an additional aqueous liquid containing a water-soluble ethylenically unsaturated monomer is added to the reaction mixture.
  • reverse phase suspension polymerization By performing the reverse phase suspension polymerization a plurality of times, it is possible to achieve a further reduction in the amount of residual volatile components.
  • the total number of polymerization steps may be 2 or 3 from the viewpoint of increasing productivity while reducing the amount of residual volatile components.
  • reaction mixture containing the water-containing gel-like polymer produced in the first polymerization step is cooled as necessary, and is at least 45 ° C, 50-100 ° C, 55-90 ° C, 60-85 ° C, Alternatively, the temperature may be adjusted to 65 to 80 ° C.
  • the reaction mixture containing the hydrogel polymer is mixed with an aqueous solvent, a water-soluble ethylenically unsaturated monomer and, if necessary, an additional aqueous liquid (second aqueous liquid) containing a radical polymerization initiator. Then, the droplet-like second aqueous liquid is dispersed in the reaction mixture.
  • the temperature of the suspension from the start of mixing the reaction mixture containing the hydrogel polymer and the second aqueous liquid to the end of mixing all of these is 35 ° C. or higher. , 40-90 ° C, 45-85 ° C, or 50-80 ° C.
  • the temperature of the reaction mixture and the second aqueous liquid before mixing, and the temperature of the suspension after mixing may also be in the above ranges. Thereby, it is possible to reduce the amount of residual volatile components of the obtained water-absorbent resin particles particularly efficiently.
  • the third and subsequent polymerization steps can also be performed in the same manner as the second polymerization step using an additional aqueous liquid (third aqueous liquid or the like).
  • the above-mentioned gas supply ratio is the water-soluble ethylenic introduced into the suspension in the n-th polymerization step (n is an integer of 1 to 3, for example).
  • the gas supply ratio is 0.1 to 3.0.
  • the gas supply ratio may be 0.12 to 2.5, 0.15 to 2.0, 0.18 to 1.5, or 0.2 to 1.2.
  • the residual volatile components can be efficiently reduced by setting the gas supply ratio after introducing the aqueous liquid containing the water-soluble ethylenically unsaturated monomer within these ranges. It becomes possible.
  • the water-soluble ethylenically unsaturated monomer aqueous solution and radical polymerization initiator contained in the aqueous liquid introduced in the second and subsequent polymerization steps are, for example, the same as those described above in the description of the first polymerization step. Types of compounds can be used in similar amounts.
  • the aqueous liquid in each polymerization step may be composed of the same monomer or the like, or may be composed of a different monomer or the like.
  • the amount of the water-soluble ethylenically unsaturated monomer contained in the aqueous liquid introduced in the second and subsequent polymerization steps is the water solubility contained in the aqueous liquid (first aqueous liquid) in the first polymerization step. It may be 20 to 250 parts by weight, 40 to 200 parts by weight, or 60 to 150 parts by weight with respect to 100 parts by weight of the ethylenically unsaturated monomer.
  • the amount of the water-soluble ethylenically unsaturated monomer in the aqueous liquid after the second time is 20 parts by mass or more, the amount of residual volatile components of the resulting water-absorbent resin particles tends to be further reduced, There exists a tendency which can suppress that the particle diameter of the water-absorbent resin particle obtained becomes excessive because the usage-amount is 250 mass parts or less.
  • the concentration of the water-soluble ethylenically unsaturated monomer in the aqueous liquid introduced in the second and subsequent polymerization steps is determined from the viewpoint of productivity improvement, from the viewpoint of productivity, aqueous solvent, water-soluble ethylenically unsaturated monomer, radical polymerization Based on the sum of the initiator and various additives, it may be 1% by mass or more, 2 to 25% by mass, 3 to 20% by mass, or 4 to 15% by mass higher than the concentration of the first aqueous liquid.
  • a hydrogel polymer is produced by the first polymerization step.
  • the manufacturing method according to the present embodiment may further include an intermediate crosslinking step of crosslinking the produced hydrogel polymer before the second and subsequent polymerization steps.
  • the intermediate crosslinking of the hydrated gel polymer is performed, for example, by mixing and heating the hydrated gel polymer and the following intermediate crosslinking agent.
  • the intermediate crosslinking agent has a functional group capable of reacting with a functional group contained in the water-soluble ethylenically unsaturated monomer (for example, a carboxyl group in the case of acrylic acid), and may be a water-soluble compound. .
  • the intermediate crosslinking agent examples include polyols such as ethylene glycol, propylene glycol, 1,4-butanediol, trimethylolpropane, glycerin, polyoxyethylene glycol, polyoxypropylene glycol, and polyglycerin; (poly) ethylene glycol diglycidyl Compounds having two or more epoxy groups such as ether, (poly) propylene glycol diglycidyl ether, and (poly) glycerin diglycidyl ether; haloepoxy compounds such as epichlorohydrin, epibromohydrin, and ⁇ -methylepichlorohydrin; Compounds having two or more isocyanate groups such as 4-tolylene diisocyanate and hexamethylene diisocyanate; 3-methyl-3-oxetanemethanol, 3-ethyl-3- Oxetane compounds such as xetanemethanol, 3-butyl-3-oxetanemethanol, 3-
  • the intermediate crosslinking agent may be a compound having two or more functional groups in the molecule that can react with the functional group of the water-soluble ethylenically unsaturated monomer.
  • a compound having two or more functional groups in the molecule that can react with the functional group of the water-soluble ethylenically unsaturated monomer.
  • examples of such a compound include the above polyol, a compound having two or more epoxy groups, a haloepoxy compound, and a compound having two or more isocyanate groups. These may be used alone or in combination of two or more.
  • the intermediate crosslinking agent is ethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, glycerin diglycidyl ether, polyethylene glycol diglycidyl ether.
  • the intermediate crosslinking agent is ethylene glycol diglycidyl ether, And at least one compound selected from propylene glycol diglycidyl ether.
  • the mixing amount of the intermediate crosslinking agent is 0.0001 to 0.03 mol, 0.0005 to 0 with respect to 100 mol of the water-soluble ethylenically unsaturated monomer used to produce the hydrogel polymer. It may be 0.02 mol or 0.001 to 0.015 mol.
  • the mixing amount of the intermediate crosslinking agent is 0.0001 mol or more, the water-soluble ethylenically unsaturated monomer in the aqueous liquid in the second polymerization step is added to the hydrogel polymer after the intermediate crosslinking step. Absorption is suppressed, and there is a tendency that a decrease in water absorption rate and swelling performance can be suppressed.
  • the reaction temperature of the intermediate crosslinking reaction may be 60 ° C. or higher, and may be 70 ° C. to the boiling point of the hydrocarbon dispersion medium used in the first polymerization step.
  • the reaction time of the intermediate cross-linking reaction varies depending on the reaction temperature, the type and amount of the intermediate cross-linking agent, and cannot be determined unconditionally, but is usually 1 to 200 minutes, 5 to 100 minutes, or 10 to 60 minutes. It may be.
  • water may be added as a solvent for dissolving the intermediate crosslinking agent in order to uniformly disperse the intermediate crosslinking agent, and a hydrophilic solvent is added.
  • a hydrophilic solvent include lower alcohols such as methyl alcohol, ethyl alcohol and isopropyl alcohol, ketones such as acetone and methyl ethyl ketone, ethers such as dioxane and tetrahydrofuran, amides such as N, N-dimethylformamide, and dimethyl sulfoxide. Examples include sulfoxide. These solvents may be used alone or in combination of two or more as necessary.
  • the water-soluble ethylenically unsaturated monomer is polymerized to further produce a particulate hydrogel polymer.
  • the obtained polymer can be obtained in various forms such as a spherical shape, a granular shape, a crushed shape, a confetti shape, and an aggregate thereof.
  • the specific surface area and From the viewpoint of improving the water absorption rate the hydrogel polymer may be granular, or may be granular having many protrusions on the surface. You may perform the above-mentioned intermediate bridge
  • the productivity of the water-absorbent resin particles can be increased by carrying out reverse phase suspension polymerization twice or more in one process. It becomes possible to improve. Surprisingly, it is possible to greatly reduce the amount of residual volatile components of the water-absorbent resin particles obtained.
  • the hydrogel polymer obtained by the first polymerization when carrying out the second and subsequent polymerizations Is present to stabilize the separation and coalescence of the aqueous droplets in the W / O type reversed phase suspension system, that is, the hydrocarbon dispersion medium is included in the aqueous droplets when the aqueous droplets collide with each other. This is presumed to be because the frequency of the formation of the O / W / O structure is suppressed.
  • the method for producing water-absorbing resin particles according to the present embodiment may further include a post-crosslinking step of cross-linking the hydrogel polymer obtained in the final polymerization step. Furthermore, the method is such that the water in the hydrogel polymer is 100% by mass based on the water-soluble ethylenically unsaturated monomer-derived component (polymer solid content) constituting the hydrogel polymer.
  • a primary drying step for adjusting the mass percentage (water content of the hydrogel polymer) to be, for example, 20 to 130% by mass may be provided before the post-crosslinking step.
  • drying method of the said primary drying process is azeotropic distillation by heating from the outside in the state which dispersed the (a) hydrogel polymer in the oil-based liquid (hydrocarbon dispersion medium).
  • a method of removing water by refluxing the hydrocarbon dispersion medium (b) A method of taking out the hydrogel polymer by decantation and drying under reduced pressure, (c) Filtering off the hydrogel polymer with a filter and drying under reduced pressure And the like.
  • the method of (a) can be selected from the simplicity in a manufacturing process.
  • the post-crosslinking agent has a functional group that can react with a functional group contained in the water-soluble ethylenically unsaturated monomer (for example, a carboxyl group in the case of acrylic acid), and may be a water-soluble compound. .
  • post-crosslinking agents include polyols such as ethylene glycol, propylene glycol, 1,4-butanediol, trimethylolpropane, glycerin, polyoxyethylene glycol, polyoxypropylene glycol, and polyglycerin; (poly) ethylene glycol diglycidyl Compounds having two or more epoxy groups such as ether, (poly) propylene glycol diglycidyl ether, and (poly) glycerin diglycidyl ether; haloepoxy compounds such as epichlorohydrin, epibromohydrin, and ⁇ -methylepichlorohydrin; Compounds having two or more isocyanate groups such as 4-tolylene diisocyanate and hexamethylene diisocyanate; 3-methyl-3-oxetanemethanol, 3-ethyl-3-o Oxetane compounds such as cetanemethanol, 3-butyl-3-oxetanemethanol, 3-methyl-3
  • the post-crosslinking agent may be a compound having in the molecule two or more functional groups capable of reacting with the functional group of the water-soluble ethylenically unsaturated monomer.
  • a compound having in the molecule two or more functional groups capable of reacting with the functional group of the water-soluble ethylenically unsaturated monomer.
  • examples of such a compound include the above polyol, a compound having two or more epoxy groups, a haloepoxy compound, and a compound having two or more isocyanate groups. These may be used alone or in combination of two or more.
  • the post-crosslinking agents a compound having two or more epoxy groups can be selected from the viewpoint of excellent reactivity.
  • the post-crosslinking agent is ethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, glycerin diglycidyl ether, polyethylene glycol diglycidyl ether.
  • at least one compound selected from the group consisting of polyglycerol glycidyl ether from the viewpoint of improving the various performances of the water-absorbing resin particles obtained, the post-crosslinking agent may be at least one compound selected from ethylene glycol diglycidyl ether and propylene glycol diglycidyl ether.
  • the mixing amount of the post-crosslinking agent is 0.0001 to 1 mol, 0.0005 to 0.5 with respect to 100 mol of the water-soluble ethylenically unsaturated monomer used to produce the hydrogel polymer. Mole, 0.001 to 0.1 mol, or 0.005 to 0.05 mol may be used.
  • the mixing amount of the post-crosslinking agent is 0.0001 mol or more, the effect of crosslinking is exhibited, and the water-absorbing resin particle surface at the time of water absorption does not become viscous, and the water absorption rate of the water-absorbing resin particles is further improved.
  • the amount is 1 mol or less, crosslinking does not become excessive, and the water absorption amount of the water absorbent resin particles tends to be further improved.
  • the mixing of the hydrogel polymer and the post-crosslinking agent can be performed after adjusting the moisture content of the hydrogel polymer to a specific range (primary drying step).
  • the postcrosslinking reaction can proceed more suitably.
  • the water content of the hydrogel polymer in the post-crosslinking step may be 20 to 130% by mass, 25 to 110% by mass, 30 to 90% by mass, 35 to 80% by mass, or 40 to 70% by mass.
  • the water content of the hydrogel polymer is the amount obtained by subtracting the amount of water extracted outside in the primary drying step from the amount of water contained in the aqueous liquid before polymerization in the entire polymerization step (the amount of water in the primary dry gel). ) And the amount of water added to the reaction mixture as necessary together with the intermediate or post-crosslinking agent, the component derived from the water-soluble ethylenically unsaturated monomer constituting the hydrogel polymer It can obtain
  • the mass of the component derived from the water-soluble ethylenically unsaturated monomer constituting the hydrogel polymer is calculated from the total mass of the water-soluble ethylenically unsaturated monomer used in the polymerization reaction as the theoretical polymer solid content. Can be obtained by calculation.
  • water may be added as a solvent for dissolving the post-crosslinking agent in order to uniformly disperse the post-crosslinking agent, and a hydrophilic solvent is added.
  • a hydrophilic solvent include lower alcohols such as methyl alcohol, ethyl alcohol and isopropyl alcohol, ketones such as acetone and methyl ethyl ketone, ethers such as dioxane and tetrahydrofuran, amides such as N, N-dimethylformamide, and dimethyl sulfoxide. Examples include sulfoxide. These solvents may be used alone or in combination of two or more as necessary.
  • the mass ratio between the water content of the gel polymer after the primary drying and the amount of solvent added is from the viewpoint of uniformly dispersing the post-crosslinking agent while rationally shortening the drying step and improving the economics of the process. 100: 0 to 60:40, 99: 1 to 70:30, 98: 2 to 80:20, or 98: 2 to 90:10.
  • the reaction temperature of the post-crosslinking reaction is 60 ° C. or higher, and may be 70 to 200 ° C. or 80 to 150 ° C.
  • the reaction temperature is 60 ° C. or higher, the post-crosslinking reaction is promoted, and there is a tendency that excessive time is not required for the reaction.
  • the reaction temperature is 200 ° C. or lower, the resulting water-absorbent resin particles are deteriorated, There exists a tendency which can suppress the fall of water absorption performance.
  • the reaction time of the post-crosslinking reaction varies depending on the reaction temperature, the type and amount of the post-crosslinking agent, and cannot be determined unconditionally, but is usually 1 to 300 minutes and may be 5 to 200 minutes. .
  • the method for producing the water-absorbent resin particles of the present embodiment includes a secondary drying step in which water, hydrocarbon dispersion medium, and the like are removed by distillation by applying energy such as heat from the outside after the post-crosslinking reaction. May be provided. By performing such secondary drying, water-absorbing resin particles having excellent fluidity tend to be obtained.
  • the method of secondary drying is not particularly limited.
  • a mixture of resin particles after being dispersed in an oily liquid (hydrocarbon dispersion medium) and then subjected to a cross-linking reaction is distilled to obtain water and a hydrocarbon dispersion medium.
  • a method of taking out resin particles by decantation and drying under reduced pressure (c) a method of separating resin particles by a filter and drying under reduced pressure.
  • the method of (a) can be selected from the simplicity in a manufacturing process.
  • water-absorbent resin particles according to the embodiment described below can be obtained.
  • the water-absorbent resin particles have a low residual volatile component amount while having an appropriately sized particle diameter and an excellent water absorption rate.
  • the median particle diameter of the water absorbent resin particles may be 100 to 600 ⁇ m. By having such a median particle diameter, it is possible to maintain good handling properties at the time of manufacturing the absorber and to design the absorber thinly.
  • the median particle diameter may be 110 to 500 ⁇ m, 120 to 400 ⁇ m, or 120 to 350 ⁇ m. The method for measuring the median particle size will be described in detail in Examples described later.
  • the water absorption speed of the physiological saline of the water absorbent resin particles may be 1 to 20 seconds. Since the water-absorbent resin particles have such an excellent water absorption speed, it is possible to prevent liquid leakage when the water-absorbent resin particles are used for absorbent articles, water-stopping materials, and the like.
  • the water absorption speed may be 1 to 15 seconds, 2 to 10 seconds, 2 to 8 seconds, or 2 to 6 seconds. The method for measuring the water absorption rate will be described in detail in the examples described later.
  • the residual volatile component amount of the water absorbent resin particles may be 1.5% by mass or less.
  • the water-absorbent resin particles have a small amount of residual volatile components, for example, to suppress the generation of odor when the water-absorbent resin particles absorb water and improve the comfort of the wearer of the absorbent article Can do.
  • the residual volatile component amount may be 1.3% by mass or less, 0.001 to 1.0% by mass, 0.01 to 0.8% by mass, or 0.1 to 0.5% by mass. Good. The method for measuring the amount of residual volatile components will be described in detail in the examples described later.
  • the water absorption amount of the physiological saline of the water-absorbent resin particles is not particularly limited, it can be increased from the viewpoint of increasing the absorption capacity of the absorbent article.
  • the water absorption amount of the physiological saline of the water-absorbent resin particles may be 30 to 90 g / g, 35 to 80 g / g, 45 to 75 g / g, 50 to 70 g / g, or 55 to 65 g / g.
  • the measuring method of the water absorption amount of the physiological saline will be described in detail in Examples described later.
  • the water-absorbent resin particles obtained by the method for producing water-absorbent resin particles of the present embodiment may contain additives such as a heat-resistant stabilizer, an antioxidant, and an antibacterial agent depending on the purpose.
  • the amount of the additive varies depending on the use of the water-absorbent resin particles, the type of additive, etc., but is 0.001 to 10 parts by mass, 0.01 to 5 parts by mass with respect to 100 parts by mass of the water-absorbent resin particles, Alternatively, it may be 0.1 to 2 parts by mass.
  • Example 1 A round bottom cylindrical separable flask (hereinafter referred to as “round bottom flask”) having an inner diameter of 100 mm equipped with a reflux condenser, a dropping funnel, a nitrogen gas introduction tube, and a stirrer was prepared.
  • the stirrer an apparatus having a two-stage inclined four-paddle blade with a blade diameter of 50 mm and a stirring blade coated on the surface with a fluororesin was used.
  • n-heptane a hydrocarbon dispersion medium
  • sorbitan monolaurate manufactured by NOF Corporation, trade name: Nonion LP-20R; HLB8.6
  • the temperature was raised to 70 ° C., and the surfactant was dissolved in n-heptane.
  • the rotating speed of the stirrer was set to 700 rpm, and the entire amount of the aqueous liquid was added to n-heptane in the round bottom flask to prepare a reverse phase suspension as a reaction liquid.
  • the temperature of the resulting reaction solution was 47 ° C.
  • 99.8% nitrogen gas was supplied into the reaction solution at a volume of 200 mL per minute for 30 minutes to replace the inside of the reaction system.
  • the round bottom flask was immersed in a 70 ° C. water bath and the temperature was raised.
  • the polymerization reaction started, and an exothermic peak was observed after 20 minutes.
  • heating was continued, and supply of nitrogen gas was stopped after 1 hour from the start of temperature increase to obtain a hydrogel polymer that had been formed.
  • n-heptane was evaporated at 120 ° C. and dried (secondary drying step) to obtain 88.2 g of granular water-absorbing resin particles.
  • Example 2 A round bottom cylindrical separable flask (hereinafter referred to as “round bottom flask”) having an inner diameter of 100 mm equipped with a reflux condenser, a dropping funnel, a nitrogen gas introduction tube, and a stirrer was prepared.
  • the stirrer an apparatus having a two-stage inclined four-paddle blade with a blade diameter of 50 mm and a stirring blade coated on the surface with a fluororesin was used.
  • n-heptane a hydrocarbon dispersion medium
  • sorbitan monolaurate manufactured by NOF Corporation, trade name: Nonion LP-20R; HLB8.6
  • the temperature was raised to 75 ° C., and the surfactant was dissolved in n-heptane.
  • the rotating speed of the stirrer was set to 700 rpm, and the entire amount of the aqueous liquid was added to n-heptane in the round bottom flask to prepare a reverse phase suspension as a reaction liquid.
  • the temperature of the obtained reaction liquid became 55 degreeC.
  • 99.8% nitrogen gas was supplied into the reaction solution at a volume of 400 mL per minute for 30 minutes to replace the inside of the reaction system.
  • the round bottom flask was immersed in a 70 ° C. water bath and the temperature was raised.
  • the polymerization reaction started, and an exothermic peak was observed after 20 minutes.
  • heating was continued, and supply of nitrogen gas was stopped after 1 hour from the start of temperature increase to obtain a hydrogel polymer that had been formed.
  • Example 2 the same operation as in Example 1 was performed to obtain 89.1 g of granular water-absorbing resin particles.
  • round bottom flask A round bottom cylindrical separable flask (hereinafter referred to as “round bottom flask”) having an inner diameter of 100 mm equipped with a reflux condenser, a dropping funnel, a nitrogen gas introduction tube, and a stirrer was prepared.
  • the stirrer an apparatus having a two-stage inclined four-paddle blade with a blade diameter of 50 mm and a stirring blade coated on the surface with a fluororesin was used.
  • n-heptane a hydrocarbon dispersion medium
  • sorbitan monolaurate manufactured by NOF Corporation, trade name: Nonion LP-20R; HLB8.6
  • the temperature was raised to 72 ° C., and the surfactant was dissolved in n-heptane.
  • the rotation speed of the stirrer was set to 500 rpm, and the entire amount of the first aqueous liquid was added to n-heptane in the round bottom flask to prepare a reverse phase suspension as a reaction liquid.
  • the temperature of the obtained reaction liquid became 51 degreeC.
  • 99.8% nitrogen gas was supplied in a volume of 500 mL per minute for 30 minutes to replace the reaction system. Thereafter, while the nitrogen gas was supplied at the same rate, the round bottom flask was immersed in a 70 ° C. water bath and the temperature was raised. As a result, the polymerization reaction started, and an exothermic peak was observed after 18 minutes.
  • first polymerization step After the polymerization, 1.24 g (0.00014 mol) of a 2% by mass aqueous ethylene glycol diglycidyl ether solution was added as an intermediate crosslinking agent, and a crosslinking reaction was performed at 75 ° C. for 30 minutes (intermediate crosslinking step).
  • the reaction mixture after completion of the crosslinking reaction with the intermediate crosslinking agent was cooled to 70 ° C. with stirring at a rotation speed of 1000 rpm.
  • the system temperature was maintained at the temperature (55 ° C.) when the dropping was completed, and 99.8% nitrogen gas was introduced into the system at the same temperature.
  • the temperature was raised by immersing the round bottom flask in a 70 ° C. water bath while supplying nitrogen gas into the reaction solution at the same rate.
  • the polymerization reaction started, and an exothermic peak was observed after 15 minutes. After that, heating was continued, and after 1 hour from the start of temperature increase, the supply of nitrogen gas was stopped to obtain a hydrogel polymer that was completely formed (second polymerization step).
  • the water content in the round bottom flask at this time was 63.9 g, and the water content of the hydrogel polymer after primary drying (after cross-linking) was 35 mass%. After preparing a mixture containing a post-crosslinking agent, the mixture was held at about 80 ° C. for 2 hours (post-crosslinking step).
  • round bottom flask A round bottom cylindrical separable flask (hereinafter referred to as “round bottom flask”) having an inner diameter of 100 mm equipped with a flow cooler, a dropping funnel, a nitrogen gas inlet tube, and a stirrer was prepared.
  • the stirrer an apparatus having a two-stage inclined four-paddle blade with a blade diameter of 50 mm and a stirring blade coated on the surface with a fluororesin was used.
  • n-heptane a hydrocarbon dispersion medium
  • sorbitan monolaurate manufactured by NOF Corporation, trade name: Nonion LP-20R; HLB8.6
  • the temperature was raised to 45 ° C., and the surfactant was dissolved in n-heptane.
  • the rotation speed of the stirrer was set to 700 rpm, and the entire amount of the aqueous liquid was added to the round bottom flask to prepare a reverse phase suspension as a reaction liquid.
  • the temperature of the reaction solution was 47 ° C.
  • 99.8% nitrogen gas was supplied into the system at a volume of 80 mL per minute for 30 minutes to replace the inside of the reaction system.
  • the round bottom flask was immersed in a 70 ° C. water bath and the temperature was raised.
  • the polymerization reaction started, and an exothermic peak was observed 30 minutes later.
  • heating was continued, and supply of nitrogen gas was stopped after 1 hour from the start of temperature increase to obtain a hydrogel polymer that had been formed.
  • round bottom flask A round bottom cylindrical separable flask (hereinafter referred to as “round bottom flask”) having an inner diameter of 100 mm equipped with a flow cooler, a dropping funnel, a nitrogen gas inlet tube, and a stirrer was prepared.
  • the stirrer an apparatus having a two-stage inclined four-paddle blade with a blade diameter of 50 mm and a stirring blade coated on the surface with a fluororesin was used.
  • n-heptane a hydrocarbon dispersion medium
  • sorbitan monolaurate manufactured by NOF Corporation, trade name: Nonion LP-20R; HLB8.6
  • the rotating speed of the stirrer was set to 700 rpm, and the entire amount of the aqueous liquid was added to the round bottom flask to prepare a reverse phase suspension as a reaction liquid.
  • the temperature of the reaction solution was 34 ° C.
  • 99.8% nitrogen gas was supplied into the reaction solution at a volume of 2700 mL per minute for 30 minutes to replace the inside of the reaction system.
  • the round bottom flask was immersed in a 70 ° C. water bath and the temperature was raised.
  • the polymerization reaction started, and an exothermic peak was observed after 10 minutes.
  • the mixture was continuously heated, and after 1 hour from the start of temperature increase, the supply of nitrogen gas was stopped to obtain a hydrogel polymer that had been formed.
  • Example 2 the same operation as in Example 1 was performed to obtain 87.1 g of granular water absorbent resin particles.
  • standard solution 3 is prepared by diluting standard solution 2 in half
  • standard solution 4 is prepared by diluting standard solution 3 in half
  • standard solution 4 is prepared by diluting standard solution 4 in half. 5 was prepared.
  • the amount of the hydrocarbon dispersion medium contained in the water-absorbent resin particles (0.10 g of the exact balance) is calculated and converted to 1 g of the water-absorbent resin particles.
  • the value obtained was defined as the residual volatile component amount (% by mass).
  • Device GC-2014 (manufactured by Shimadzu Corporation) Headspace autosampler: HT200H (manufactured by Hamilton Company) Filler: Squalane 25% Shimalite (NAW) (101) 80-100 mesh Column: 3.2mm ⁇ ⁇ 2.1m Column temperature: 80 ° C Inlet temperature: 180 ° C Detector temperature: 180 ° C Detector: FID Carrier gas: N 2 Vial heating temperature: 110 ° C Syringe set temperature: 130 ° C
  • Odor sensory test (6-level odor intensity display method) The odor derived from the hydrocarbon dispersion medium during swelling of the water-absorbent resin particles was evaluated by the following method. 20.0 g of a 0.9 mass% sodium chloride aqueous solution (physiological saline) at 25 ° C. was added to a glass bottle with a lid (mayonnaise bottle) having an internal volume of 140 mL, and a rotor having a length of 3 cm was added and stirred. 2.0 g of water-absorbent resin particles were put in a glass bottle with a lid and sealed. The odor derived from the hydrocarbon dispersion medium in the glass bottle was determined by five analysts according to the evaluation criteria shown in Table 1, and the average value was taken as the odor evaluation result.
  • a JIS standard sieve has an opening of 850 ⁇ m, an opening of 600 ⁇ m, an opening of 500 ⁇ m, an opening of 425 ⁇ m, an opening of 300 ⁇ m, an opening of 250 ⁇ m, an opening of 150 ⁇ m. Combined in order of sieve and saucer.
  • B JIS standard sieve from above, sieve with 425 ⁇ m opening, sieve with 250 ⁇ m opening, sieve with 180 ⁇ m opening, sieve with 150 ⁇ m opening, sieve with 106 ⁇ m opening, sieve with 75 ⁇ m opening, 45 ⁇ m opening Combined in order of sieve and saucer.
  • the above water-absorbing resin particles were put into a sieve located at the top of the combined sieves, and the water-absorbing resin particles were classified by shaking for 20 minutes using a low-tap shaker.
  • the mass of the water-absorbing resin particles remaining on each sieve is calculated as a percentage by mass with respect to the total amount, and by integrating in order from the larger particle diameter, the water-absorbing resin particles remaining on the sieve and the sieve
  • the relationship between the mass percentage and the integrated value was plotted on a logarithmic probability paper. By connecting the plots on the probability paper with a straight line, the particle diameter corresponding to an integrated mass percentage of 50 mass% was defined as the median particle diameter.
  • the powder handling property of the water-absorbent resin particles was visually evaluated according to the standards by five analysts. The evaluation selected by three or more analysts was defined as the powder handling property of the water-absorbent resin particles. Good: Less dusting. Fluidity is moderate, and operations such as weighing and cleaning are easy. Defect: Much powdered. Since the fluidity is low, operations such as weighing and cleaning are difficult.
  • the water-absorbent resin particles obtained in Examples 1 to 3 are all excellent in water-absorbing performance such as a water-absorbing speed while having a moderate particle diameter and a small amount of residual volatile components. I understand. On the other hand, it can be seen that the water-absorbent resin particles obtained in the comparative example are not sufficient in any of these characteristics. In particular, the amount of residual volatile components when the supply ratio of the inert gas is lower than specified (Comparative Example 1) and when the inert gas is excessively supplied (Comparative Example 2) is larger than that of the example. Therefore, the effect of the present invention is obvious.
  • the water-absorbent resin particles obtained by the production method according to the present embodiment are used for sanitary materials such as paper diapers, sanitary goods, pet sheets, water and water-resisting materials, soil improvement materials and other agricultural and horticultural materials, and power and communication cable waterstops. It can be used in various fields such as for industrial materials such as materials and anti-condensation materials.
  • the water-absorbent resin particles are preferably used in the fields of adult diapers, incontinence pads, toilet training pants and specific hygiene materials such as daily napkins, cable waterproofing materials, pet seats, simple toilets, etc. It is done.

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  • Health & Medical Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
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  • Polymerisation Methods In General (AREA)
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Abstract

La présente invention concerne un procédé de production de particules de résine absorbant l'eau impliquant une étape de polymérisation dans laquelle une suspension est préparée par mise en suspension, dans une solution à base d'huile contenant un milieu de dispersion hydrocarboné et un tensioactif avec HLB 6 ou plus, d'une solution aqueuse contenant de l'eau et des monomères à insaturation éthylénique solubles dans l'eau dissous dans l'eau, et dans laquelle les monomères à insaturation éthylénique solubles dans l'eau sont polymérisés tout en fournissant un gaz inerte dans la suspension. Le taux de fourniture de gaz représenté par le rapport entre le volume de gaz inerte fourni en une minute et le volume total de la solution aqueuse et de la dispersion hydrocarbonée va de 0,1 à 3,0.
PCT/JP2013/051206 2012-02-20 2013-01-22 Procédé de production de particules de résine absorbant l'eau WO2013125279A1 (fr)

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JP2018050835A (ja) * 2016-09-27 2018-04-05 ユニ・チャーム株式会社 吸収性物品
WO2018102480A1 (fr) * 2016-11-30 2018-06-07 Brown University Procédés de fabrication de particules polymères hyper-conformables, et procédés d'utilisation et compositions
EP3424959A4 (fr) * 2016-03-02 2019-11-13 Sumitomo Seika Chemicals Co. Ltd. Procédé de production de particules de résine absorbant l'eau
WO2020203723A1 (fr) * 2019-03-29 2020-10-08 住友精化株式会社 Résine absorbant l'eau et matériau colmatant

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JPH11147902A (ja) * 1997-11-14 1999-06-02 Nippon Shokubai Co Ltd 吸水性樹脂の製造方法、吸水剤およびその製造方法
JP2010024360A (ja) * 2008-07-18 2010-02-04 Kao Corp 吸水性樹脂の製造方法

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JPH10147606A (ja) * 1996-11-14 1998-06-02 Elf Atochem Sa 水中への溶解または膨潤速度が速い親水性ポリマーの製造方法
JPH11147902A (ja) * 1997-11-14 1999-06-02 Nippon Shokubai Co Ltd 吸水性樹脂の製造方法、吸水剤およびその製造方法
JP2010024360A (ja) * 2008-07-18 2010-02-04 Kao Corp 吸水性樹脂の製造方法

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP3424959A4 (fr) * 2016-03-02 2019-11-13 Sumitomo Seika Chemicals Co. Ltd. Procédé de production de particules de résine absorbant l'eau
US10835887B2 (en) 2016-03-02 2020-11-17 Sumitomo Seika Chemicals Co., Ltd Process for producing water-absorbing resin particles
JP2018050835A (ja) * 2016-09-27 2018-04-05 ユニ・チャーム株式会社 吸収性物品
JP7085795B2 (ja) 2016-09-27 2022-06-17 ユニ・チャーム株式会社 吸収性物品
WO2018102480A1 (fr) * 2016-11-30 2018-06-07 Brown University Procédés de fabrication de particules polymères hyper-conformables, et procédés d'utilisation et compositions
US11772061B2 (en) 2016-11-30 2023-10-03 Brown University Methods of fabricating hyper compliant polymer particles and methods of use and compositions
WO2020203723A1 (fr) * 2019-03-29 2020-10-08 住友精化株式会社 Résine absorbant l'eau et matériau colmatant
JPWO2020203723A1 (fr) * 2019-03-29 2020-10-08
CN113906056A (zh) * 2019-03-29 2022-01-07 住友精化株式会社 吸水性树脂和阻水材料

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