WO2022075256A1 - Procédé de fabrication de particules de résine absorbant l'eau - Google Patents

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

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Publication number
WO2022075256A1
WO2022075256A1 PCT/JP2021/036615 JP2021036615W WO2022075256A1 WO 2022075256 A1 WO2022075256 A1 WO 2022075256A1 JP 2021036615 W JP2021036615 W JP 2021036615W WO 2022075256 A1 WO2022075256 A1 WO 2022075256A1
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Prior art keywords
fine powder
mass
granulated
particles
water
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PCT/JP2021/036615
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English (en)
Japanese (ja)
Inventor
直矢 淡路
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住友精化株式会社
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Priority to JP2022555466A priority Critical patent/JPWO2022075256A1/ja
Publication of WO2022075256A1 publication Critical patent/WO2022075256A1/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
    • B01J20/30—Processes for preparing, regenerating, or reactivating
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J3/00—Processes of treating or compounding macromolecular substances
    • C08J3/12—Powdering or granulating

Definitions

  • This disclosure relates to a method for producing water-absorbent resin particles.
  • water-absorbent resin particles For use as water-absorbent resin particles, there is a suitable particle size range such as 180 to 850 ⁇ m.
  • a suitable particle size range such as 180 to 850 ⁇ m.
  • the fine powder is used as granulated particles by increasing the particle size by granulation (for example, Patent Document 1). Even for granulated particles produced using fine powder, the water absorption rate is required to be sufficiently high.
  • One aspect of the present disclosure relates to providing a production method capable of obtaining water-absorbent resin particles containing granulated particles having an excellent water absorption rate, as compared with the case of granulating using only fine powder that has not undergone a coagulation step.
  • One aspect of the present disclosure is that the polymer fine particles passing through a sieve having an opening of 180 ⁇ m are mixed with water to aggregate the polymer fine particles to form a first lump, and the first lump is formed. Is dried and crushed to form granulated fine powder that passes through a sieve with an opening of 180 ⁇ m, and the particle group containing the granulated fine powder is mixed with water to agglomerate the particle group into a second mass.
  • the content of the granulated fine particles in the particle group includes the formation of an article and the formation of granulated particles by drying and crushing the second agglomerate, and the content of the granulated fine particles in the particle group is the total amount of the particle group.
  • the present invention relates to a method for producing water-absorbent resin particles containing granulated particles, which are 80% by mass or more and 100% by mass or less.
  • the particle group may further contain polymer fine powder passing through a sieve having an opening of 180 ⁇ m in an amount of more than 0% by mass and 20% by mass or less with respect to the total amount of the particle group.
  • the polymer fine powder contained in the particle group agglomerates the polymer fine powder by mixing the polymer fine powder with water to form a lump, and the lump is dried and pulverized. It may be a fine powder excluding the fine powder formed by the method containing the above.
  • the production method may further include classifying the granulated particles.
  • the content of the fine powder in the granulated fine powder that passes through the sieve with an opening of 180 ⁇ m and does not pass through the sieve with an opening of 150 ⁇ m is 30% by mass or less with respect to the total amount of the granulated fine powder. good.
  • (meth) acrylic means both acrylic and methacrylic.
  • acrylate and “methacrylate” are also referred to as “(meth) acrylate”.
  • (Poly) shall mean both with and without the "poly” prefix.
  • the upper or lower limit of the numerical range at one stage may be optionally combined with the upper or lower limit of the numerical range at another stage.
  • the upper limit value or the lower limit value of the numerical range may be replaced with the value shown in the examples.
  • Water-soluble means that it exhibits a solubility in water of 5% by mass or more at 25 ° C.
  • each component in the composition means the total amount of the plurality of substances present in the composition when a plurality of substances corresponding to each component are present in the composition, unless otherwise specified.
  • “Saline” means a 0.9% by mass sodium chloride aqueous solution.
  • Sieve means JIS standard sieve.
  • the polymer fine particles that pass through a sieve having an opening of 180 ⁇ m are mixed with water to aggregate the polymer fine particles into a first mass.
  • the first lump is dried and crushed to form granulated fine powder that passes through a sieve with an opening of 180 ⁇ m, and the granulated fine powder is 80% by mass based on the total amount of the particle group.
  • the particle group containing the content of 100% by mass or less is mixed with water to aggregate the particle group to form a second lump, and the second lump is dried and pulverized. Includes forming granulated particles.
  • the method for producing the water-absorbent resin particles is to mix the polymer fine particles that pass through a sieve with an opening of 180 ⁇ m with water to agglomerate the polymer fine particles to obtain a lump (first lump).
  • the lump is dried and crushed to obtain granulated fine powder passing through a sieve having an opening of 180 ⁇ m, and a group of particles containing the granulated fine powder in a content of 80% by mass or more and 100% by mass or less is mixed with water. It may include aggregating the particle group by mixing to obtain a lump (second lump) again, and drying and pulverizing the obtained lump again to obtain granulated particles.
  • the granulated fine powder generated when the fine powder is granulated and granulated is used again for granulation, and the particle group used at the time of re-granulation contains the granulated fine powder in a high ratio. It is characterized by that.
  • granulation refers to aggregating particles to obtain particles having a larger particle diameter than the original particles.
  • the water-absorbent resin particles having a faster water absorption rate than the case where the fine powder (primary fine powder) that has not undergone the aggregation step, which is generated in the production process of the water-absorbent resin particles is granulated alone. Can be manufactured.
  • the polymer fine powder is a fine powder that passes through a sieve having an opening of 180 ⁇ m, and is used to form a first lump.
  • the polymer fine powder used to form the first lump may be, for example, fine powder that has not undergone the aggregation step (hereinafter, also referred to as “primary fine powder”), and is granulated fine powder that has undergone the aggregation step described later. May be.
  • the primary fine particles are fine powders generated in the production of polymer particles used for water-absorbent resin particles, and can be, for example, fine powders generated when a block-shaped or coarse-particle-shaped polymer is crushed into particles. ..
  • the primary fine powder is a fine powder formed by a method including mixing the polymer fine powder with water to agglomerate the polymer fine powder to form a lump, and drying and pulverizing the lump. It may be a fine powder to be removed.
  • the primary fine powder can be obtained, for example, by polymerizing a monomer to obtain a hydrogel-like polymer, and then drying, pulverizing and classifying the hydrogel-like polymer.
  • a method for obtaining primary fine powder will be described in detail.
  • a monomer containing an ethylenically unsaturated monomer is polymerized to obtain a hydrogel-like polymer.
  • the water-containing gel-like polymer may be a cross-linked polymer formed by polymerization of a monomer containing an ethylenically unsaturated monomer and formed into a gel-like state containing water.
  • the water-absorbent resin particles obtained by the production method according to the present embodiment can contain a crosslinked polymer formed by polymerizing a monomer containing an ethylenically unsaturated monomer.
  • the crosslinked polymer has a monomeric unit derived from an ethylenically unsaturated monomer. That is, the water-absorbent resin particles according to the present embodiment can have a structural unit derived from an ethylenically unsaturated monomer.
  • Polymerization can be performed, for example, by an aqueous solution polymerization method.
  • aqueous solution polymerization method the polymerization of the monomer by the aqueous solution polymerization method will be described.
  • the ethylenically unsaturated monomer may be water-soluble.
  • the ethylenically unsaturated monomer include carboxylic acid-based monomers such as (meth) acrylic acid, maleic acid, maleic anhydride, fumaric acid and salts thereof; (meth) acrylamide, N, N-dimethyl ( Nonionic monomers such as meta) acrylamide, 2-hydroxyethyl (meth) acrylate, N-methylol (meth) acrylamide, polyethylene glycol mono (meth) acrylate; N, N-diethylaminoethyl (meth) acrylate, N, Amino group-containing unsaturated monomers such as N-diethylaminopropyl (meth) acrylate and diethylaminopropyl (meth) acrylamide and quaternized products thereof; vinyl sulfonic acid, styrene sulfonic acid, 2- (meth) acrylamide-2-methyl propane.
  • Examples thereof include sulfonic acid-based monomers such as sulfonic acid, 2- (meth) acryloylethanesulfonic acid and salts thereof.
  • sulfonic acid-based monomers such as sulfonic acid, 2- (meth) acryloylethanesulfonic acid and salts thereof.
  • the ethylenically unsaturated monomer one type may be used alone, or two or more types may be used in combination.
  • the ethylenically unsaturated monomer is at least one selected from the group consisting of (meth) acrylic acid and salts thereof, maleic acid, fumaric acid, (meth) acrylamide, and N, N-dimethylacrylamide, or (meth). It may contain at least one selected from acrylic acid and salts thereof.
  • (Meta) Acrylic acid and salts thereof may be copolymerized with other ethylenically unsaturated monomers. In this case, the ratio of the (meth) acrylic acid and its salt to the total amount of the ethylenically unsaturated monomer may be 70 to 100 mol%, 80 to 100 mol%, or 90 to 100 mol%. ..
  • the ethylenically unsaturated monomer may contain at least one of (meth) acrylic acid and a salt thereof.
  • the acid group is previously an alkaline neutralizing agent if necessary.
  • an alkaline neutralizer include alkali metal salts such as sodium hydroxide, sodium carbonate, sodium hydrogencarbonate, potassium hydroxide and potassium carbonate; ammonia and the like.
  • alkaline neutralizers may be used in the form of an aqueous solution in order to simplify the neutralization operation.
  • One type of alkaline neutralizer may be used alone, or two or more types may be used in combination.
  • the acid group may be neutralized before the polymerization of the ethylenically unsaturated monomer as a raw material, or may be performed during or after the polymerization.
  • the degree of neutralization of the ethylenically unsaturated monomer by the alkaline neutralizer enhances the water absorption performance by increasing the osmotic pressure of the obtained water-absorbent resin particles, and the safety due to the presence of the excess alkaline neutralizer. From the viewpoint of preventing problems such as, usually, it may be 10 to 100 mol%, 30 to 90 mol%, 40 to 85 mol%, or 50 to 80 mol%.
  • the degree of neutralization is the degree of neutralization for all the acid groups of the ethylenically unsaturated monomer.
  • the ethylenically unsaturated monomer can usually be used in the state of an aqueous solution.
  • concentration of the ethylenically unsaturated monomer in the aqueous solution containing the ethylenically unsaturated monomer may be 20% by mass or more and the saturation concentration or less, and is 25 to 70% by mass. %, Or 30 to 50% by mass.
  • the amount of the ethylenically unsaturated monomer used is the total amount of the monomer (the total amount of the monomer for obtaining the water-absorbent resin particles. For example, the total amount of the monomers giving the structural unit of the crosslinked polymer. The same applies hereinafter). It may be 70 to 100 mol%, 80 to 100 mol%, 90 to 100 mol%, 95 to 100 mol%, or 100 mol%. Among them, the ratio of (meth) acrylic acid and its salt may be 70 to 100 mol% with respect to the total amount of the monomer, 80 to 100 mol%, 90 to 100 mol%, 95 to 100 mol%, or It may be 100 mol%. "Ratio of (meth) acrylic acid and its salt” means the ratio of the total amount of (meth) acrylic acid and its salt.
  • the water-absorbent resin particles are, for example, water-absorbent resin particles containing a crosslinked polymer having a structural unit derived from an ethylenically unsaturated monomer, and the ethylenically unsaturated monomer includes (meth) acrylic acid and. It contains at least one compound selected from the group consisting of the salts, and the ratio of (meth) acrylic acid and its salts is 70 to 100 mol% with respect to the total amount of monomers for obtaining water-absorbent resin particles. It may be a thing.
  • the monomer aqueous solution may contain a polymerization initiator.
  • the polymerization of the monomer contained in the aqueous monomer solution is started by adding a polymerization initiator to the aqueous monomer solution and, if necessary, heating, irradiating with light or the like.
  • the polymerization initiator include a photopolymerization initiator and a radical polymerization initiator.
  • the polymerization initiator may be a water-soluble radical polymerization initiator.
  • the polymerization initiator may be, for example, an azo compound, a peroxide or the like.
  • Examples of the azo compound include 2,2'-azobis [2- (N-phenylamidino) propane] dihydrochloride and 2,2'-azobis ⁇ 2- [N- (4-chlorophenyl) amidino] propane ⁇ .
  • the azo compounds are 2,2'-azobis (2-amidinopropane) dihydrochloride and 2,2'-azobis ⁇ 2- [1. -(2-Hydroxyethyl) -2-imidazolin-2-yl] propane ⁇ dihydrochloride, or 2,2'-azobis [N- (2-carboxyethyl) -2-methylpropionamidine] tetrahydrate There may be.
  • One of these azo compounds may be used alone, or two or more thereof may be used in combination.
  • peroxide examples 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, t. -Organic peroxides such as butylperoxyacetate, t-butylperoxyisobutyrate, t-butylperoxypivalate; peroxides such as hydrogen peroxide can be mentioned.
  • persulfates such as potassium persulfate, ammonium persulfate, and sodium persulfate
  • methyl ethyl ketone peroxide methyl isobutyl ketone peroxide
  • di-t-butyl peroxide di-t-butyl peroxide
  • t-butyl cumyl peroxide t.
  • potassium persulfate, ammonium persulfate, sodium persulfate, or hydrogen peroxide may be used from the viewpoint of obtaining water-absorbent resin particles having good water absorption performance
  • potassium persulfate, Ammonium persulfate or sodium persulfate may be used.
  • One of these peroxides may be used alone, or two or more thereof may be used in combination.
  • redox polymerization initiator it can also be used as a redox polymerization initiator by using a polymerization initiator and a reducing agent in combination.
  • the reducing agent include sodium sulfite, sodium hydrogen sulfite, ferrous sulfate, and L-ascorbic acid.
  • the amount of the polymerization initiator is 0.05 to 1 mol with respect to 1 mol of the monomer. It may be 1 mmol, 0.08 to 0.8 mmol, or 0.1 to 0.7 mmol.
  • the monomer aqueous solution may contain an internal cross-linking agent.
  • the obtained cross-linked polymer can have cross-linking by the internal cross-linking agent in addition to self-cross-linking by the polymerization reaction as its internal cross-linking structure.
  • the internal cross-linking agent may contain a compound having a (meth) acrylic group, an allyl group, an epoxy group, or an amino group.
  • a compound having two or more of these reactive functional groups can be used as an internal cross-linking agent.
  • compounds having a (meth) acrylic group include (poly) ethylene glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate (poly) propylene glycol di (meth) acrylate, and glycerol tri (meth) acrylate. Examples thereof include trimethylolpropane di (meth) acrylate and N, N'-methylenebis (meth) acrylamide.
  • Examples of compounds having an allyl group include triallylamine.
  • Examples of compounds having an epoxy group include (poly) ethylene glycol diglycidyl ether, (poly) propylene glycol diglycidyl ether, (poly) glycerin diglycidyl ether, and epichlorohydrin.
  • Examples of compounds having an amino group include triethylenetetramine, ethylenediamine, and hexamethylenediamine.
  • As the internal cross-linking agent one type may be used alone, or two or more types may be used in combination.
  • the amount used is 0.02 to 1 mol of the monomer from the viewpoint of adjusting the performance balance of CRC and the like in the polymer fine powder, the cross-linked polymer particles, and the water-absorbent resin particles. It may be 1.0 mmol, 0.05 to 0.8 mmol, or 0.1 to 0.6 mmol.
  • the monomer aqueous solution may contain additives such as a chain transfer agent and a thickener, if necessary.
  • a chain transfer agent include thiols, thiolic acids, secondary alcohols, hypophosphorous acid, phosphorous acid and the like.
  • the thickener include carboxymethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, methyl cellulose, polyethylene glycol, polyacrylic acid, polyacrylic acid neutralized product, polyacrylamide and the like. These may be used alone or in combination of two or more.
  • a solvent other than water such as a water-soluble organic solvent, may be appropriately added to the monomer aqueous solution.
  • the polymerization method is, for example, a static polymerization method in which the monomer aqueous solution is polymerized without stirring (for example, a static state), or a stirring polymerization method in which the monomer aqueous solution is polymerized while being stirred in the reaction apparatus. It's okay.
  • a hydrogel-containing polymer may be obtained by static polymerization of an aqueous solution, which is a static polymerization method. In the static polymerization method, it is possible to obtain a single block-shaped hydrogel-like polymer that occupies substantially the same volume as the monomer aqueous solution present in the reaction vessel when the polymerization is completed.
  • the form of production may be batch, semi-continuous, continuous, etc.
  • a polymerization reaction can be carried out while continuously supplying a monomer aqueous solution to a belt conveyor-shaped continuous polymerization apparatus to obtain a water-containing gel having a continuous shape such as a band shape. ..
  • the polymerization temperature varies depending on the polymerization initiator used, but may be 0 to 130 ° C. or 10 to 110 ° C. from the viewpoint of increasing the productivity by rapidly advancing the polymerization and shortening the polymerization time.
  • the polymerization time is appropriately set depending on the type or amount of the polymerization initiator used, the reaction temperature and the like, but may be 1 to 200 minutes or 5 to 100 minutes.
  • the hydrogel polymer may be coarsely crushed in advance when it is subjected to drying.
  • the coarsely crushed product obtained by coarsely crushing the water-containing gel-like polymer may be in the form of particles or may have an elongated shape as if the particles were connected.
  • the size of the minimum side of the coarsely crushed product may be, for example, about 0.1 to 15 mm or about 1.0 to 10 mm.
  • the size of the maximum side of the coarsely crushed product may be about 0.1 to 200 mm, or about 1.0 to 150 mm.
  • a kneader for example, a pressurized kneader, a double-armed kneader, etc.
  • a meat chopper for example, a pressurized kneader, a double-armed kneader, etc.
  • a cutter mill for example, a pharmacomill, etc.
  • the double-armed kneader or a meat chopper, a cutter mill, etc. You may.
  • a dried product can be obtained by removing the solvent containing water in the lumpy hydrogel polymer or the coarsely crushed product thereof by heating and / or blowing air.
  • the drying method may be a method of natural drying, heat drying, vacuum drying or the like.
  • the drying may be performed under normal pressure or reduced pressure, for example, and may be performed under an air flow such as nitrogen in order to improve the drying efficiency.
  • a plurality of methods may be used in combination.
  • the heating temperature for drying under normal pressure may be, for example, 70 to 250 ° C. or 80 to 200 ° C.
  • the water content of the dried product obtained by drying may be, for example, 20% by mass or less, 10% by mass or less, or 5% by mass or less, and may be 0% by mass or more or 1% by mass or more.
  • the moisture content of the dried product obtained by drying may be 0 to 20% by mass or 1 to 10% by mass.
  • a particle group containing fine powder is obtained.
  • roller mill stamp mill, jet mill, high-speed rotary crusher (ultracentrifuge crusher, hammer mill, pin mill, rotor beater mill, etc.), container-driven mill (rotary mill, vibration mill, etc.)
  • a crusher such as a planetary mill
  • the crusher may have an opening on the outlet side, such as a perforated plate, a screen, a grid, etc., for controlling the maximum particle size of the crushed particles.
  • the shape of the opening may be polygonal, circular, or the like, and the maximum diameter of the opening may be 0.1 to 5 mm, 0.3 to 3.0 mm, or 0.5 to 1.5 mm.
  • the pulverization may be performed so that at least a part of the particle group becomes fine powder having a particle diameter such that it passes through a sieve having an opening of 180 ⁇ m.
  • the pulverization is performed, for example, by pulverizing the polymer particles having an appropriate particle diameter of about 180 ⁇ m or more and less than 850 ⁇ m, and fine powder having a particle diameter such that the particles pass through a sieve having an opening of 180 ⁇ m. It can be done in such a way that particles occur.
  • the fine particles that pass through a sieve having an opening of 180 ⁇ m can be used as the primary fine powder.
  • the particle group is classified by using the sieve to obtain primary fine powder that passes through a sieve having a mesh opening of 180 ⁇ m.
  • Classification refers to an operation of dividing a certain particle group into two or more particle groups having different particle size distributions according to the particle size.
  • a known classification method can be used, and for example, screen classification or wind power classification may be used.
  • Screen classification is a method of classifying particles on a screen into particles that pass through the mesh of the screen and particles that do not pass through the screen by vibrating the screen. Screen classification can be performed using, for example, a vibrating sieve, a rotary shifter, a cylindrical stirring sieve, a blower shifter, or a low-tap shaker.
  • Wind power classification is a method of classifying particles using the flow of air.
  • the “particles passing through a sieve having an opening of 180 ⁇ m” refers to particles having such a size, and is not limited to those using a sieve as a classification step.
  • the CRC of the primary fine powder may be, for example, 65 g / g or less, 60 g / g or less, 58 g / g or less, 30 g / g or more, 33 g / g or more, 35 g / g or more, 37 g / g or more, 41 g / g. As mentioned above, it may be 45 g / g or more, or 50 g / g or more.
  • the CRC of the primary fine powder may be 30 to 65 g / g, 33 to 60 g / g, or 35 to 58 g / g. CRC is measured by the method described in Examples described later with reference to the EDANA method (NWSP 241.0.R2 (15), pages 769 to 778).
  • the polymer fine powder that passes through a sieve having an opening of 180 ⁇ m is mixed with water to aggregate the polymer fine powder to form a first lump, which is said to be the same. It is contained as a part of granulated particles obtained by drying and pulverizing the first mass.
  • the granulated fine powder used in the production method according to the present embodiment is granulated particles that pass through a sieve having an opening of 180 ⁇ m.
  • the process from mixing the fine powder to agglutination of the fine powder (cutting if necessary), drying of the first lump, and pulverization may be collectively referred to as a granulation process.
  • the method for producing the granulated fine powder will be described in detail.
  • the agglomeration step is a step of aggregating the polymer fine powder by mixing the polymer fine powder with water to form a lump.
  • Granulated fine powder is formed by drying and pulverizing the formed lumps.
  • the polymer fine powder used for producing the granulated fine powder may be, for example, the above-mentioned primary fine powder, or may be a granulated fine powder obtained through an aggregation step using the primary fine powder, and is a mixture thereof. You may.
  • the granulated fine powder formed by drying and pulverizing the first lump can be a granulated fine powder obtained by using the primary fine powder.
  • a component such as a water-soluble salt, a water-soluble polymerizable monomer such as an ethylenically unsaturated monomer, a cross-linking agent, or a hydrophilic organic solvent may be added to the water mixed with the polymer fine powder. .. That is, the water may be mixed with the polymer fine powder in the form of an aqueous liquid containing other components added to the water. The ratio of water in the aqueous liquid may be, for example, 80 to 100% by mass.
  • the cross-linking agent for example, the above-mentioned internal cross-linking agent or the same cross-linking agent as the surface cross-linking agent described later can be used.
  • the temperature at which the polymer fine powder and water are mixed may be, for example, 30 to 150 ° C, 60 to 110 ° C, or 80 to 100 ° C.
  • the amount of water mixed with the polymer fine powder is, for example, 10 parts by mass or more, 30 parts by mass or more, 50 parts by mass or more, 80 parts by mass or more, or 90 parts by mass with respect to 100 parts by mass of the polymer fine powder as a raw material. It may be 200 parts by mass or less, 150 parts by mass or less, 130 parts by mass or less, or 100 parts by mass or less.
  • the amount of water mixed with the polymer fine powder is 10 to 200 parts by mass, 30 to 150 parts by mass, 50 to 130 parts by mass, or 80 to 100 parts by mass with respect to 100 parts by mass of the polymer fine powder as a raw material. There may be.
  • water may be added dropwise to the polymer fine powder little by little, the entire amount of water may be added at once, or water may be sprayed, and the state of water vapor. May be mixed with.
  • the polymer fine powder and water can be mixed, for example, by using various stirrers having stirring blades.
  • a flat plate blade a lattice blade, a paddle blade, a propeller blade, an anchor blade, a turbine blade, a Faudler blade, a ribbon blade, a full zone blade, a max blend blade and the like can be used.
  • the flat plate blade has a shaft (stirring shaft) and a flat plate portion (stirring portion) arranged around the shaft. Further, the flat plate portion may have a slit or the like.
  • the stirring type mixer include a mortar mixer, a dual-arm kneader, a continuous kneader, a ladyge mixer and the like.
  • the mixing time of the polymer fine powder and water is 30 to 150 seconds or 60 to 120 seconds after the total amount of the polymer fine powder and water is put into the same container. You may.
  • the polymer fine powder aggregates with each other, and the first lump can be obtained.
  • the obtained first mass is dried.
  • the first lump may be cut to about 3 to 10 mm in advance before being subjected to drying.
  • the drying, pulverization, and classification of the first lump can be performed by the same method as the drying, pulverizing, and classification steps in the above-mentioned production of the primary fine powder. After granulation, drying and pulverization, and if necessary, classification can be performed to obtain fine powder that passes through a sieve having an opening of 180 ⁇ m, that is, granulated fine powder.
  • the size of the granulated fine powder may be one that passes through a sieve with an opening of 180 ⁇ m, but further, the content of fine powder that passes through a sieve with an opening of 180 ⁇ m and does not pass through a sieve with an opening of 150 ⁇ m is the content of granulation. It may be 30% by mass or less, or 25% by mass or less, based on the total amount of the fine powder. It is considered that when the content of the granulated fine particles that do not pass through the sieve having an opening of 150 ⁇ m is not more than a certain level, the water absorption rate of the obtained granulated particles or the water-absorbent resin particles tends to be further increased.
  • the content of the fine powder that passes through the sieve with an opening of 180 ⁇ m and does not pass through the sieve with an opening of 150 ⁇ m is, for example, 10% by mass or more or 15% by mass or more with respect to the total amount of the granulated fine powder. It's okay.
  • the content of the fine powder that passes through the sieve with an opening of 180 ⁇ m and does not pass through the sieve with an opening of 150 ⁇ m is 10% by mass or more and 30% by mass or less or 25% by mass with respect to the total amount of the granulated fine powder. It may be less than or equal to, and may be 15% by mass or more and 30% by mass or less or 25% by mass or less.
  • the proportion of the particles passing through the sieve having an opening of 150 ⁇ m in the granulated fine powder may be, for example, 70% by mass or more, or 75% by mass or more, and 90% by mass or less or 85% with respect to the total amount of the granulated fine powder. It may be mass% or less.
  • the proportion of the particles passing through the sieve having an opening of 150 ⁇ m in the granulated fine powder may be 70 to 90% by mass or 75 to 85% by mass with respect to the total amount of the granulated fine powder.
  • aggregation (hereinafter, also referred to as “main aggregation”) is performed using the above-mentioned particle group containing granulated fine powder.
  • the production method according to the present embodiment includes mixing a particle group containing granulated fine powder with water to agglomerate the particle group to obtain a second lump.
  • the content of the granulated fine powder in the particle group used for the main aggregation is 80% by mass or more and 100% by mass or less with respect to the total amount of the particle group.
  • the content of the granulated fine powder in the particle group used for the main aggregation is 83% by mass or more, 85% by mass or more, 88% by mass or more, 90% by mass or more, 93% by mass or more, 95% by mass with respect to the total amount of the particle group. It may be more than or equal to 98% by mass or more.
  • the content of the granulated fine powder in the particle group used for the main aggregation may be 99% by mass or less, 98% by mass or less, or 95% by mass or less with respect to the total amount of the particle group.
  • the content of the granulated fine powder in the particle group used for the main aggregation may be 83% by mass or more and 99% by mass or less, 98% by mass or less, or 95% by mass or less with respect to the total amount of the particle group, 85. It may be 99% by mass or less, 98% by mass or less, or 95% by mass or less in mass% or more, and may be 99% by mass or less, 98% by mass or less, or 95% by mass or less in 88% by mass or more. , 90% by mass or more and 99% by mass or less, 98% by mass or less, or 95% by mass or less, 93% by mass or more and 99% by mass or less, 98% by mass or less, or 95% by mass or less. It may be 95% by mass or more and 99% by mass or less, or 98% by mass or less, or 98% by mass or more and 99% by mass or less.
  • the particle group used for the main aggregation may contain the above-mentioned primary fine powder (polymer fine powder that has not undergone the aggregation step and passes through a sieve having an opening of 180 ⁇ m).
  • the content of the primary fine powder with respect to the total amount of the particle group is, for example, more than 0% by mass, 3% by mass or more, 5% by mass or more, 8% by mass or more, 10% by mass or more, or 15 It may be mass% or more.
  • the content of the primary fine powder with respect to the total amount of the particle group is, for example, 20% by mass or less, 18% by mass or less, 15% by mass or less, 13% by mass or less, 10% by mass or less, 8% by mass or less, or 5% by mass or less. It's okay.
  • the content of the primary fine powder in excess of 0% by mass is 20% by mass or less, 18% by mass or less, 15% by mass or less, 13% by mass or less, 10% by mass or less, 8% by mass or less, or 5% by mass. It may be 3% by mass or more and 20% by mass or less, 18% by mass or less, 15% by mass or less, 13% by mass or less, 10% by mass or less, 8% by mass or less, or 5% by mass or less.
  • the particle group used for the main aggregation may contain polymer particles other than the primary fine powder and the granulated fine powder.
  • the total amount of the primary fine powder and the granulated fine powder is 90% by mass or more, 92% by mass or more, 95% by mass or more, 98% by mass or more, 99% by mass or more, or more than the total amount of the particle group used for the main aggregation. It may be 100% by mass.
  • the total amount of the primary fine powder and the granulated fine powder may be 100% by mass or less or 99% by mass or less with respect to the total amount of the particle group used for the main aggregation.
  • the total amount of the primary fine powder and the granulated fine powder may be 90 to 100% by mass with respect to the total amount of the particle group used for the main aggregation.
  • the method of aggregating the particle group by mixing the particle group containing the granulated fine powder with water to obtain a second lump, and the method of cutting the second lump as necessary, drying and pulverizing the second lump are described above. Similar aspects to the method in the production of granulated fines can be applied.
  • the granulated fine particles may be used in combination with different primary particles, for example, fine powders obtained under different production conditions, or those derived from fine powders obtained in different production lots under the same production conditions.
  • the particle group contains primary fine particles or other polymer particles in addition to the granulated fine powder, or when a plurality of types of granulated fine powder are mixed and used, the particle group is uniformly mixed in advance before being mixed with water. You may.
  • the water absorption rate of the obtained granulated particles or water-absorbent resin particles can be further increased as compared with the case of granulating using only the primary fine powder.
  • the larger the medium particle size of the water-absorbent resin particles the slower the water absorption rate.
  • the water-absorbent resin particles obtained by the production method according to the present embodiment have a large medium particle size. Has a high water absorption rate.
  • the granulated particles obtained by pulverization may be classified as needed. That is, the method for producing water-absorbent resin particles according to the present embodiment may include a step of classifying the granulated particles. If necessary, a plurality of classification steps may be performed, such as pulverizing the classified particles again and repeating the pulverization step and the classification step, or the classification step may be performed after the surface cross-linking step described later.
  • the classification can be performed in the same manner as the classification method in the above-mentioned method for producing primary fine powder or granulated fine powder.
  • the method for producing the water-absorbent resin particles may include a step of performing surface cross-linking of the granulated particles. That is, the granulated particles contained in the water-absorbent resin particles obtained by the production method according to the present embodiment may be surface-crosslinked.
  • Surface cross-linking can be performed, for example, by adding a cross-linking agent (surface cross-linking agent) for performing surface cross-linking to the granulated particles and reacting them.
  • the addition of the surface cross-linking agent may be carried out at any timing after the second lump obtained by the main aggregation is pulverized, and may be carried out before or after the classification.
  • the cross-linking density in the vicinity of the surface of the granulated particles is increased, so that the water absorption performance of the obtained water-absorbent resin particles can be improved.
  • the surface cross-linking agent can be added to the granulated particles, for example, by adding a surface cross-linking agent solution or by spraying the surface cross-linking agent solution.
  • the surface cross-linking agent may be dissolved in a solvent such as water and / or alcohol, and the surface cross-linking agent solution may be added to the granulated particles.
  • the surface cross-linking step may be carried out once or divided into a plurality of times of two or more times.
  • the surface cross-linking agent may contain, for example, two or more functional groups (reactive functional groups) having reactivity with a functional group derived from an ethylenically unsaturated monomer.
  • functional groups reactive functional groups
  • examples of the surface cross-linking agent include polyols such as ethylene glycol, propylene glycol, 1,4-butanediol, trimethylolpropane, glycerin, polyoxyethylene glycol, polyoxypropylene glycol, and polyglycerin; (poly) ethylene glycol di.
  • Polyglycidyl compounds such as glycidyl ether, (poly) glycerin diglycidyl ether, (poly) glycerin triglycidyl ether, (poly) propylene glycol polyglycidyl ether, (poly) glycerol polyglycidyl ether; epichlorohydrin, epibromhydrin, ⁇ - Haloepoxy compounds such as methylepicrolhydrin; compounds having two or more reactive functional groups such as isocyanate compounds such as 2,4-tolylene diisocyanate and hexamethylene diisocyanate; 3-methyl-3-oxetanemethanol, 3-ethyl-3- Oxetane compounds such as oxetane methanol, 3-butyl-3-oxetane methanol, 3-methyl-3-oxetane ethanol, 3-ethyl-3-oxetan ethanol, 3-butyl-3-oxet
  • the surface cross-linking agents are (poly) ethylene glycol diglycidyl ether, (poly) ethylene glycol triglycidyl ether, (poly) glycerin diglycidyl ether, (poly) glycerin triglycidyl ether, (poly) propylene glycol polyglycidyl ether, (poly). ) Polyglycidyl compounds such as glycerol polyglycidyl ether and / or polyols such as ethylene glycol, propylene glycol, 1,4-butanediol, trimethylolpropane, polyoxyethylene glycol and polyoxypropylene glycol may be contained, and polyglycidyl may be contained. It may contain a compound. These surface cross-linking agents may be used alone or in combination of two or more. For example, a polyglycidyl compound and polyols may be used in combination.
  • the amount of the surface cross-linking agent added is usually 100 mol with respect to the total amount of the ethylenically unsaturated monomer used for the polymerization from the viewpoint of appropriately increasing the cross-linking density in the vicinity of the surface of the water-absorbent resin particles (granulated particles). , 0.0001 to 4.0 mol, or 0.001 to 2.0 mol.
  • the surface cross-linking step may be performed in the presence of water in the range of 1 to 200 parts by mass with respect to 100 parts by mass of the ethylenically unsaturated monomer.
  • the water content can be adjusted by appropriately using a water-soluble organic solvent such as water and / or alcohol.
  • a water-soluble organic solvent such as water and / or alcohol.
  • the treatment temperature of the surface cross-linking agent is appropriately set according to the surface cross-linking agent used, and may be 20 to 250 ° C.
  • the treatment time with the surface cross-linking agent may be 1 to 200 minutes or 5 to 100 minutes.
  • the surface cross-linking may be performed only once or at a plurality of timings.
  • the water-absorbent resin particles obtained by the production method according to the present embodiment include the above-mentioned granulated particles.
  • the water-absorbent resin particles may be composed of only granulated particles, for example, a gel stabilizer, a metal chelating agent (ethylenediamine 4 acetic acid and its salt, diethylenetriamine 5 acetic acid and its salt, for example, diethylenetriamine 5 acetate 5 sodium and the like, etc. ), An additional component such as a fluidity improver (lubricant) may be further contained. Additional components may be placed inside, on the surface, or both of the granulated particles.
  • the water-absorbent resin particles may contain a plurality of inorganic particles arranged on the surface of the granulated particles.
  • the production method according to the present embodiment may further include a step of adhering the inorganic particles to the surface of the granulated particles.
  • the shape of the granulated particles or the water-absorbent resin particles obtained by the production method according to the present embodiment may be, for example, a crushed shape or a shape formed by aggregating crushed particles.
  • the medium particle diameter of the granulated particles or the water-absorbent resin particles may be 250 ⁇ m or more, 280 ⁇ m or more, 300 ⁇ m or more, 320 ⁇ m or more, or 340 ⁇ m or more, and may be 850 ⁇ m or less, 800 ⁇ m or less, 750 ⁇ m or less, 700 ⁇ m or less, 650 ⁇ m or less, It may be 600 ⁇ m or less, 550 ⁇ m or less, 500 ⁇ m or less, 450 ⁇ m or less, 420 ⁇ m or less, 400 ⁇ m or less, or 380 ⁇ m or less.
  • the medium particle size of the granulated particles or the water-absorbent resin particles may be 250 to 850 ⁇ m, 280 to 750 ⁇ m, 300 to 650 ⁇ m, 320 to 550 ⁇ m, or 340 to 450 ⁇ m.
  • the water absorption rate of the water-absorbent resin particles obtained by the production method according to the present embodiment is, for example, 42 seconds or less, 40 seconds or less, 38 seconds or less, 37 seconds or less, 36 seconds or less, 35 seconds or less, 33 seconds or less, or It may be 31 seconds or less, and may be 27 seconds or more, 29 seconds or more, 31 seconds or more, or 33 seconds or more.
  • the water absorption rate of the water-absorbent resin particles may be 27 to 42 seconds or 29 to 40 seconds. A method for measuring the water absorption rate will be shown in Examples described later.
  • the CRC of the granulated particles or the water-absorbent resin particles obtained by the production method according to the present embodiment is, for example, 30 g / g or more, 35 g / g or more, 38 g / g or more, 40 g / g or more, 43 g / g or more, 45 g.
  • / G or more 48 g / g or more, 50 g / g or more, 55 g / g or more, or 60 g / g or more, 68 g / g or less, 65 g / g or less, 62 g / g or less, 60 g / g or less, 58 g It may be / g or less, 55 g / g or less, 53 g / g or less, or 50 g / g or less.
  • the CRC of the granulated particles or the water-absorbent resin particles may be 30 to 68 g / g, 35 to 68 g / g, 38 to 65 g / g, or 40 to 65 g / g.
  • the water-absorbent resin particles obtained by the production method according to the present embodiment have excellent water absorption, and are, for example, sanitary materials such as disposable diapers and sanitary products, agricultural and horticultural materials such as water-retaining agents and soil conditioners, water-stopping agents, and dew condensation prevention. It can be used in fields such as industrial materials such as agents.
  • the centrifuge holding capacity (CRC), water absorption rate, medium particle size, and particle size distribution of fine powder were measured.
  • the centrifuge holding capacity was measured by the following procedure with reference to the EDANA method (NWSP 241.0.R2 (15), pages 769 to 778). The measurement was performed in an environment where the temperature was 25 ° C. ⁇ 2 ° C. and the humidity was 50% ⁇ 10%.
  • the measurement target is a fraction of the primary fine particles and granulated particles that passes through a sieve having an opening of 850 ⁇ m and does not pass through a sieve having an opening of 180 ⁇ m. The results are shown in Tables 1 to 3.
  • a non-woven fabric with a size of 60 mm x 170 mm (product name: Heat Pack MWA-18, manufactured by Nippon Paper Papylia Co., Ltd.) was folded in half in the longitudinal direction to adjust the size to 60 mm x 85 mm.
  • a 60 mm ⁇ 85 mm nonwoven fabric bag was produced by pressure-bonding the nonwoven fabrics to each other on both sides extending in the longitudinal direction with a heat seal (a crimping portion having a width of 5 mm was formed on both sides along the longitudinal direction). 0.2 g of the particles to be measured were precisely weighed and contained in the non-woven fabric bag. Then, the non-woven fabric bag was closed by crimping the remaining one side extending in the lateral direction with a heat seal.
  • the entire non-woven fabric bag was completely moistened by floating the non-woven fabric bag on 1000 g of physiological saline contained in a stainless steel vat (240 mm ⁇ 320 mm ⁇ 45 mm) without folding the non-woven fabric bag.
  • a stainless steel vat 240 mm ⁇ 320 mm ⁇ 45 mm
  • the non-woven fabric bag was taken out from the physiological saline solution. Then, the non-woven fabric bag was put in a centrifuge (manufactured by Kokusan Co., Ltd., model number: H-122). After the centrifugal force in the centrifuge reached 250 G, the non-woven fabric bag was dehydrated for 3 minutes. After dehydration, the mass Ma [g] of the non-woven fabric bag containing the mass of the gel was weighed.
  • the non-woven fabric bag was subjected to the same operation as described above without accommodating the particles to be measured, and the mass Mb [g] of the non-woven fabric bag after dehydration was measured.
  • CRC [g / g] was calculated based on the following formula.
  • Mc [g] is a precise value of 0.2 g of the mass of the particle to be measured used for the measurement.
  • CRC [(Ma-Mb) -Mc] / Mc
  • the water absorption rate of the physiological saline of the particles was measured by the following procedure based on the Vortex method.
  • the measurement target is a fraction of the obtained granulated particles that passes through a sieve having an opening of 850 ⁇ m and does not pass through a sieve having an opening of 180 ⁇ m.
  • 50 ⁇ 0.1 g of physiological saline adjusted to a temperature of 25 ⁇ 0.2 ° C. in a constant temperature water tank was weighed in a beaker having an internal volume of 100 mL.
  • a vortex was generated by stirring at a rotation speed of 600 rpm using a magnetic stirrer bar (8 mm ⁇ ⁇ 30 mm, without ring).
  • the medium particle size of the particles was measured in an environment of 25 ⁇ 2 ° C. and a humidity of 50 ⁇ 10% by the following procedure.
  • the measurement target is a fraction of the obtained granulated particles that passes through a sieve having an opening of 850 ⁇ m and does not pass through a sieve having an opening of 180 ⁇ m.
  • 10 g of particle powder is continuously and fully automated with a sonic vibration type sieving measuring instrument (robot shifter RPS-205, manufactured by Seishin Corporation) and JIS standard openings of 850 ⁇ m, 600 ⁇ m, 500 ⁇ m, 425 ⁇ m, 300 ⁇ m, 250 ⁇ m and 180 ⁇ m. Sifting was performed using a sieve and a saucer.
  • the mass of the particles remaining on each sieve was calculated as a mass percentage to the total amount.
  • the mass percentages of the particles remaining on each sieve were integrated in order from the one with the largest particle size, and the relationship between the mesh opening of the sieve and the integrated value of the mass percentages of the particles remaining on the sieve was plotted on a logarithmic probability paper. .. By connecting the plots on the probability paper with a straight line, the particle size corresponding to the integrated mass percentage of 50% by mass was obtained, and this was defined as the medium particle size.
  • Tables 1 to 3 The results are shown in Tables 1 to 3.
  • the upper part of the stainless steel vat was covered with a polyethylene film. After adjusting the temperature of the mixture in the stainless steel vat to 25 ° C., the amount of dissolved oxygen was adjusted to 0.1 ppm or less by substituting the mixture with nitrogen.
  • the viscosity of the reaction solution increased as the polymerization reaction progressed, and then the reaction solution.
  • the thermometer installed at 4 minutes after the completion of dropping the aqueous hydrogen peroxide solution showed 103 ° C., and then the temperature began to decrease.
  • a stainless steel bat containing a hydrogel polymer containing a coalescence was immersed in a water bath at 75 ° C., and the hydrogel polymer was aged in that state for 20 minutes.
  • the aged hydrogel polymer was sequentially charged into a meat chopper 12VR-750SDX manufactured by Kiren Royal Co., Ltd. and coarsely crushed.
  • the diameter of the hole of the plate located at the outlet of the meat chopper was 6.4 mm.
  • the obtained crushed hydrogel polymer was spread on a wire mesh having an opening of 0.8 cm ⁇ 0.8 cm and dried with hot air at 180 ° C. for 30 minutes to obtain a dried product.
  • Atypical crushed particles (A) were obtained by pulverizing the dried product using a centrifugal pulverizer (ZM200 manufactured by Retsch, screen diameter 1 mm, 6000 rpm).
  • the particle swarm (A) was classified using a sieve having a mesh size of 850 ⁇ m and a sieve having a mesh size of 180 ⁇ m.
  • the crosslinked polymer particles (A1) which passed through the 850 ⁇ m sieve and did not pass through the 180 ⁇ m sieve, and the crosslinked polymer fine powder (primary fine powder (a1)) which was the fraction which passed through the 180 ⁇ m sieve. )) was obtained.
  • the CRC of the primary fine powder (a1) was 56 g / g, the content of the 150-180 ⁇ m fraction was 30% by mass, and the content of the 150 ⁇ m passing fraction was 70% by mass.
  • the four slits are arranged in the width direction of the flat plate portion, the width of the inner two slits is 1 cm, and the width of the outer two slits is 0.5 cm.
  • the length of the flat plate portion is about 10 cm, and the width of the flat plate portion is about 6 cm.
  • the coarsely crushed dried product was crushed using a centrifugal crusher (ZM200 manufactured by Retsch, screen diameter 1 mm, 6000 rpm), and further classified by a sieve having an opening of 850 ⁇ m and a sieve having an opening of 180 ⁇ m.
  • the crosslinked polymer particles (granulation particles (A2)), which are fractions that passed through the 850 ⁇ m sieve and did not pass through the 180 ⁇ m sieve, and the crosslinked polymer fine powder, which is the fraction that passed through the 180 ⁇ m sieve.
  • the content of the granulated fine powder (a2) in the 150 to 180 ⁇ m fraction was 17% by mass, and the content of the 150 ⁇ m passing fraction was 83% by mass.
  • Ion-exchanged water 406.25 g and polyethylene glycol diacrylate (Blemmer ADE-400A) 3.55 g were added to 2781.72 g of sodium acrylate partially neutralized solution to obtain a reaction solution (monomer aqueous solution).
  • the dissolved oxygen content was adjusted to 0.1 ppm or less by substituting the reaction solution with nitrogen gas for 30 minutes in a nitrogen gas atmosphere.
  • a 5 L stainless steel double-armed kneader manufactured by Irie Shokai Co., Ltd.
  • a jacket equipped with a thermometer and a nitrogen blow tube and having two sigma-shaped blades with a lid that can be opened and closed was prepared.
  • the above reaction solution was supplied to the kneader, and the inside of the kneader was replaced with nitrogen gas while keeping the reaction solution at 25 ° C.
  • the water-containing gel-like polymer taken out is cut into an appropriate size, and then passed through a 850 ⁇ m sieve by performing the same operations as in the drying step, the pulverization step, and the classification step in the production of the primary fine powder of Production Example 1.
  • the crosslinked polymer particles (B1) which were fractions that did not pass through the 180 ⁇ m sieve and the crosslinked polymer fine powder (primary fine powder (b1)) which was the fraction that passed through the 180 ⁇ m sieve were obtained.
  • the CRC of the primary fine powder (b1) was 37 g / g
  • the content of the 150-180 ⁇ m fraction was 26% by mass
  • the content of the 150 ⁇ m passing fraction was 74% by mass.
  • Example 1 In the same manner as in Comparative Example 2 except that the amount of the primary fine powder (a1) used was changed to 5 g and the amount of the granulated fine powder (a2) used was changed to 45 g, the sieve passed through an 850 ⁇ m sieve and a 180 ⁇ m sieve. Crosslinked polymer particles (granulated particles (Y2)), which were not fractions, were obtained.
  • Example 2 [Granulation process] By performing the same operation as the granulation step of Production Example 1 using 40 g of granulated fine powder (a2), the crosslinked polymer particles which are fractions that passed through the 850 ⁇ m sieve and did not pass through the 180 ⁇ m sieve. (Granulated particles (A3)) were obtained.
  • Example 3 [Granulation process] By performing the same operation as the granulation step of Production Example 1 using 40 g of granulated fine powder (b2), the crosslinked polymer particles which are fractions that passed through the 850 ⁇ m sieve and did not pass through the 180 ⁇ m sieve. (Granulated particles (B3)) were obtained.
  • the primary fine powder alone is aggregated by aggregating the particle group containing the granulated fine powder at a certain ratio or more. It was confirmed that the water absorption rate of the obtained granulated particles could be increased.
  • Example 4 In the same manner as in Comparative Example 2 except that 12.5 g of granulated fine powder (a2) and 37.5 g of granulated fine powder (b2) were used without using the primary fine powder, the sieve passed through an 850 ⁇ m sieve and a 180 ⁇ m sieve. Cross-linked polymer particles (granulated particles (AB3)), which are fractions that did not pass through the above, were obtained.
  • granulated particles (AB3) Cross-linked polymer particles

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Abstract

L'invention concerne un procédé de fabrication de particules de résine absorbant l'eau contenant des particules granulaires. Le procédé de l'invention inclut : une étape au cours de laquelle une fine poudre de polymère passant au travers d'un tamis de maille de １８０μｍ s'agglomère par mélange de celle-ci avec une eau, et un premier objet en bloc est ainsi formé ; une étape au cours de laquelle le premier objet en bloc est séché et broyé, et une fine poudre granulaire passant au travers d'un tamis de maille de １８０μｍ, est formée ; une étape au cours de laquelle un ensemble de particules contenant ladite fine poudre granulaire, est mélangé à une eau, ce qui agglomère ledit ensemble de particules, et un second objet en bloc est ainsi formé ; et une étape au cours de laquelle ledit second objet en bloc est séché et broyé, et les particules granulaires sont ainsi formées. Le rapport de teneur en fine poudre granulaire dans ledit ensemble de particules, est supérieur ou égal à 80% en masse et inférieur ou égal à 100% en masse pour la quantité totale dudit ensemble de particules.
PCT/JP2021/036615 2020-10-06 2021-10-04 Procédé de fabrication de particules de résine absorbant l'eau WO2022075256A1 (fr)

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Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH11106514A (ja) * 1997-06-18 1999-04-20 Nippon Shokubai Co Ltd 吸水性樹脂造粒物の製造方法
JPH11140194A (ja) * 1997-06-23 1999-05-25 Nippon Shokubai Co Ltd 吸水性樹脂組成物およびその製造方法
JP2004067878A (ja) * 2002-08-06 2004-03-04 Toagosei Co Ltd 含水ゲル粒子の製造方法
JP2005015787A (ja) * 2003-06-03 2005-01-20 Nippon Shokubai Co Ltd 吸水材の製造方法
JP2013034942A (ja) * 2011-08-08 2013-02-21 Nippon Shokubai Co Ltd 粒子状吸水剤の製造方法
WO2019221235A1 (fr) * 2018-05-16 2019-11-21 株式会社日本触媒 Procédé de production d'une résine absorbant l'eau
JP2020520390A (ja) * 2018-04-03 2020-07-09 エルジー・ケム・リミテッド 高吸水性樹脂の製造方法

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH11106514A (ja) * 1997-06-18 1999-04-20 Nippon Shokubai Co Ltd 吸水性樹脂造粒物の製造方法
JPH11140194A (ja) * 1997-06-23 1999-05-25 Nippon Shokubai Co Ltd 吸水性樹脂組成物およびその製造方法
JP2004067878A (ja) * 2002-08-06 2004-03-04 Toagosei Co Ltd 含水ゲル粒子の製造方法
JP2005015787A (ja) * 2003-06-03 2005-01-20 Nippon Shokubai Co Ltd 吸水材の製造方法
JP2013034942A (ja) * 2011-08-08 2013-02-21 Nippon Shokubai Co Ltd 粒子状吸水剤の製造方法
JP2020520390A (ja) * 2018-04-03 2020-07-09 エルジー・ケム・リミテッド 高吸水性樹脂の製造方法
WO2019221235A1 (fr) * 2018-05-16 2019-11-21 株式会社日本触媒 Procédé de production d'une résine absorbant l'eau

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