WO2022075258A1 - Procédé de production de particules de résine absorbant l'eau - Google Patents

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

Info

Publication number
WO2022075258A1
WO2022075258A1 PCT/JP2021/036621 JP2021036621W WO2022075258A1 WO 2022075258 A1 WO2022075258 A1 WO 2022075258A1 JP 2021036621 W JP2021036621 W JP 2021036621W WO 2022075258 A1 WO2022075258 A1 WO 2022075258A1
Authority
WO
WIPO (PCT)
Prior art keywords
polymer
cross
particles
water
polymer particles
Prior art date
Application number
PCT/JP2021/036621
Other languages
English (en)
Japanese (ja)
Inventor
崇志 居藤
Original Assignee
住友精化株式会社
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 住友精化株式会社 filed Critical 住友精化株式会社
Priority to JP2022555468A priority Critical patent/JPWO2022075258A1/ja
Publication of WO2022075258A1 publication Critical patent/WO2022075258A1/fr

Links

Images

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J20/00—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof
    • B01J20/22—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof comprising organic material
    • B01J20/26—Synthetic macromolecular compounds
    • 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
    • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F220/00—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
    • C08F220/02—Monocarboxylic acids having less than ten carbon atoms; Derivatives thereof
    • C08F220/04—Acids; Metal salts or ammonium salts thereof
    • C08F220/06—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
    • 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

  • the present disclosure relates to a method for producing water-absorbent resin particles.
  • the water-absorbent resin particles include cross-linking the polymer in the polymer particles by forming the polymer particles containing the polymer and then heating the mixture of the polymer particles and the solution containing the surface cross-linking agent. It may be manufactured by a method (for example, Patent Document 1). Generally, by cross-linking with a surface cross-linking agent, it is possible to obtain water-absorbent resin particles having improved characteristics such as a water absorption ratio under pressure.
  • coarse particles having a particle size exceeding 850 ⁇ m may be formed. Since it is often necessary to remove such coarse particles, it is desirable to suppress the formation of coarse particles from the viewpoint of improving production efficiency. Further, when a strongly crosslinked polymer is formed during the polymerization reaction, a large amount of fine powder tends to be easily formed as the dry gel containing the polymer is pulverized.
  • One aspect of the present disclosure is the formation of coarse particles associated with the cross-linking step in the case of producing water-absorbent resin particles by a method comprising cross-linking the polymer in the polymer particles formed by grinding a dry gel.
  • the present invention relates to a method capable of efficiently cross-linking a polymer in a polymer particle while suppressing the above-mentioned, and further suppressing the formation of fine powder due to pulverization of a dry gel.
  • One aspect of the present disclosure relates to a method for producing water-absorbent resin particles containing polymer particles.
  • the method comprises a step of forming a powder of polymer particles by crushing a dry gel containing a polymer and a cross-linking agent, and a reaction of the polymer with the cross-linking agent by heating the powder. Includes a step of cross-linking with.
  • the polymer can be efficiently crosslinked while suppressing the formation of coarse particles in the crosslinking step. Further, according to the method according to one aspect of the present disclosure, as compared with the case where the polymer is strongly crosslinked by crosslinking during the polymerization reaction, the generation of fine particles in the step of crushing the dry gel is suppressed, and the paper diaper, etc. It is possible to form a powder having a medium particle size suitable for use in an absorbent article of.
  • the present invention is not limited to the following examples.
  • (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.
  • the materials exemplified in the present specification may be used alone or in combination of two or more.
  • An example of a method for producing water-absorbent resin particles is a step of forming a powder of the polymer particles by crushing a dry gel containing a polymer and a cross-linking agent, and a step of heating the powder of the polymer particles. , Includes a step of cross-linking the polymer by reaction with a cross-linking agent.
  • the dry gel has, for example, a step of forming a hydrogel-like polymer containing a polymer, a cross-linking agent and water by a polymerization reaction in a polymerization reaction solution containing a monomer, a cross-linking agent and water, and a water-containing gel-like weight. It is formed through a step of forming a dry gel by removing water from the coalescence.
  • Polymerization reaction in a polymerization reaction solution containing a monomer, a cross-linking agent and water forms a polymer cross-linked by a part of the cross-linking agent, an unreacted cross-linking agent, and a hydrogel-like polymer containing water. May be done.
  • the cross-linking of the polymer in the polymerization reaction solution is referred to as "internal cross-linking”
  • the cross-linking of the polymer in the polymer particles formed by grinding the dry gel is referred to as "post-crosslinking”.
  • the polymerization reaction solution may be a monomer aqueous solution in which the monomer is dissolved in water.
  • the polymerization reaction solution thickens as the polymerization reaction progresses, and then gels to form a hydrogel polymer.
  • the polymerization reaction liquid loses its fluidity as the polymerization reaction progresses.
  • the mixture after the polymerization reaction solution loses its fluidity may also be referred to as a polymerization reaction solution for convenience.
  • the polymerization reaction is carried out with the polymerization reaction solution contained in the reaction vessel.
  • the monomer is a compound that forms a polymer that imparts water absorption to the polymer particles and the water-absorbent resin particles by polymerization.
  • the monomer may be an ethylenically unsaturated monomer.
  • the ethylenically unsaturated monomer is, for example, (meth) acrylic acid and a salt thereof, 2- (meth) acrylamide-2-methylpropanesulfonic acid and a salt thereof, (meth) acrylamide, N, N-dimethyl (meth).
  • the amino group may be quaternized.
  • the monomer may contain at least one compound selected from the group consisting of acrylic acid and salts thereof, methacrylic acid and salts thereof, acrylamide, methacrylamide, and N, N-dimethylacrylamide.
  • the monomer may contain at least one compound selected from the group consisting of acrylic acid and salts thereof, methacrylic acid and salts thereof, and acrylamide.
  • the monomer may contain at least one compound selected from the group consisting of acrylic acid and salts thereof, and methacrylic acid and salts thereof.
  • the polymerization reaction solution may contain a monomer other than the ethylenically unsaturated monomer.
  • the proportion of the ethylenically unsaturated monomer (particularly (meth) acrylic acid and a salt thereof) may be 70 to 100 mol% with respect to the total amount of the monomers in the reaction solution.
  • the proportion of (meth) acrylic acid and a salt thereof in the ethylenically unsaturated monomer may be 70 to 100 mol%.
  • the concentration of the monomer in the polymerization reaction solution before the polymerization reaction may be, for example, 20 to 50% by mass or 20 to 40% by mass based on the mass of the polymerization reaction solution.
  • the cross-linking agent in the polymerization reaction solution contains at least a reactive compound for post-cross-linking (hereinafter, may be referred to as "latent cross-linking agent").
  • latent cross-linking agent a reactive compound for post-cross-linking
  • the polymer may be crosslinked before the post-crosslinking step by a part of the reactive compounds introduced into the polymerization reaction solution as a latent cross-linking agent.
  • the reactive compound for post-crosslinking may be an alkylene carbonate, an aliphatic polyhydric alcohol, or a combination thereof. These reactive compounds can easily remain in the hydrogel polymer. Therefore, for example, the maximum temperature reached by the polymerization reaction solution during the polymerization reaction may be 40 to 125 ° C., and the reaction time may be in the range of 3 to 180 minutes.
  • the reaction time here can be the time from the start of the polymerization reaction to the removal from the water-containing gel-like polymer reaction vessel.
  • the alkylene carbonate used as a latent cross-linking agent is, for example, 1,3-dioxolane-2-one (ethylene carbonate), 4-methyl-1,3-dioxolan-2-one (propylene carbonate), 4,5-dimethyl-.
  • 1,3-Dioxolane-2-one 4,4-dimethyl-1,3-dioxolane-2-one, 4-ethyl-1,3-dioxolane-2-one, 4-hydroxymethyl-1,3-dioxolane -2-one (glycerin carbonate), 1,3-dioxane-2-one (trymethylene carbonate), 4-methyl-1,3-dioxane-2-one, 4,6-dimethyl-1,3-dioxane- It may be at least one compound selected from the group consisting of 2-one and 1,3-dioxepan-2-one.
  • the aliphatic polyhydric alcohol used as a latent cross-linking agent is, for example, ethylene glycol, diethylene glycol, propylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycol, 1,3-propanediol, dipropylene glycol, 2,2,4.
  • the amount of the reactive compound (latent cross-linking agent) contained in the polymerization reaction solution before the polymerization reaction is 0.2 to 60.0 mmol, 1.0 to 33.0 mmol, or 2 per 1 mol of the monomer. It may be 0.0 to 6.0 mmol.
  • the amount of the latent cross-linking agent is within these ranges, the polymer can be cross-linked more efficiently while suppressing the formation of coarse particles in the post-cross-linking step.
  • the cross-linking agent can further contain a reactive compound for internal cross-linking (hereinafter, may be referred to as "internal cross-linking agent"). That is, the cross-linking agent can include a first reactive compound that mainly functions as an internal cross-linking agent for internal cross-linking and a second reactive compound that mainly functions as a latent cross-linking agent for post-cross-linking. ..
  • the second reactive compound can be the reactive compound exemplified as the latent cross-linking agent.
  • the first reactive compound may be a compound that is consumed during the polymerization reaction and does not substantially remain in the hydrogel-like polymer that is dried after the polymerization. A part of the first reactive compound may remain in the dry gel, in which case the remaining first reactive compound together with the second reactive compound is a cross-linking agent for post-crosslinking (latent cross-linking agent). ) May function.
  • the first reactive compound may be a bifunctional or higher functional compound that copolymerizes with the monomer.
  • the first reactive compound may be, for example, a compound having a (meth) acrylic group, an allyl group, an epoxy group, or an amino group as the reactive functional group.
  • the compound having a (meth) acrylic group may be a (meth) acrylic compound having two or more (meth) acrylic groups, and examples thereof include (poly) ethylene glycol di (meth) acrylate and trimethylolpropane. Examples include tri (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, (poly) glycerin polyglycidyl ether and epichlorohydrin. Will be. Examples of compounds having an amino group include triethylenetetramine, ethylenediamine, and hexamethylenediamine.
  • the amount of the first reactive compound (internal cross-linking agent) contained in the polymerization reaction solution before the polymerization reaction may be 0.002 to 3.0 mmol per 1 mol of the monomer.
  • the amount of the first reactive compound (internal cross-linking agent) is within this range, the generation of fine powder in the step of pulverizing the dry gel tends to be suppressed.
  • the polymer is crosslinked by the first reactive compound, and at least a part of the second reactive compound is not yet contained in the hydrogel polymer.
  • a combination is selected so that the reaction conditions that remain as the cross-linking agent for the reaction can be set.
  • the second reactive compound latent cross-linking agent
  • the first reactive compound is a (meth) acrylic compound. If there is, it is possible to easily form a hydrogel-like polymer containing a polymer crosslinked mainly by the first reactive compound while leaving an unreacted second reactive compound.
  • a polymer cross-linked by a part of the reactive compounds used as a latent cross-linking agent is formed, and the reactive compound is formed.
  • a hydrogel-like polymer may be formed under the reaction conditions in which a part of the reaction remains as an unreacted cross-linking agent.
  • the polymerization reaction solution may further contain an initiator (particularly, a radical polymerization initiator).
  • Initiators may include persulfates, azo compounds, organic peroxides or combinations thereof.
  • the amount of initiator may be 0.01-15 mmol per mole of monomer. When two or more initiators are used, the amount of each initiator may be 0.01 to 15 mmol per mole of the monomer.
  • persulfate examples include potassium persulfate, ammonium persulfate, and sodium persulfate.
  • azo compounds examples include 2,2'-azobis [2- (N-phenylamidino) propane] dihydrochloride, 2,2'-azobis ⁇ 2- [N- (4-chlorophenyl) amidino] propane ⁇ 2 Hydrochloride, 2,2'-azobis ⁇ 2- [N- (4-hydroxyphenyl) amidino] propane ⁇ dihydrochloride, 2,2'-azobis [2- (N-benzylamidino) propane] dihydrochloride, 2,2'-azobis [2- (N-allylamidino) propane] dihydrochloride, 2,2'-azobis (2-amidinopropane) dihydrochloride, 2,2'-azobis ⁇ 2- [N-( 2-Hydroxyethyl) amidino] propane ⁇ dihydrochloride, 2,2'-azobis [2- (5-methyl-2-imidazolin-2-yl) propane] dihydrochloride, 2,2'-azobis [2- (2-imidazolin-2-yl)
  • the radical polymerization initiators are 2,2'-azobis (2-amidinopropane) dihydrochloride, 2,2'-azobis ⁇ 2- [1- (2-hydroxy). Ethyl) -2-imidazolin-2-yl] propane ⁇ dihydrochloride, 2,2'-azobis [N- (2-carboxyethyl) -2-methylpropionamidine] tetrahydrate, and 2,2'- It may contain at least one azo compound selected from azobis [2- (2-imidazolin-2-yl) propane] dihydrochloride.
  • organic peroxides examples include methyl ethyl ketone peroxide, methyl isobutyl ketone peroxide, di-t-butyl peroxide, t-butyl cumyl peroxide, t-butyl peroxyacetate, t-butyl peroxyisobutyrate, etc. And t-butylperoxypivalate.
  • the polymerization reaction solution may further contain a cleavage accelerator.
  • the cleavage accelerator is a compound that lowers the temperature at which the polymerization reaction is initiated by the initiator. When the polymerization reaction is started at a low temperature, water-absorbent resin particles having better water-absorbing performance can be easily obtained.
  • the cleavage promoter can be, for example, a reducing agent, an oxidizing agent or a combination thereof. A part or all of the cleavage accelerator may be added later to the reaction solution containing the monomer, the initiator and water to initiate the polymerization reaction.
  • the amount of cleavage promoter may be, for example, 0.01 to 1.0 mol per 1 mol of initiator.
  • the reducing agent used as the cleavage accelerator may be, for example, at least one compound selected from the group consisting of sodium sulfite, sodium hydrogen sulfite, ferrous sulfate, and L-ascorbic acid.
  • the oxidizing agent used as a cleavage promoter may be, for example, at least one compound selected from the group consisting of hydrogen peroxide, sodium perborate, perphosphate, perphosphate, and potassium permanganate. good.
  • the polymerization reaction solution may further contain a chain transfer agent.
  • the chain transfer agent may include, for example, hypophosphorous acid, phosphorous acid or a combination thereof.
  • the massive hydrogel-like polymer formed by the polymerization reaction is taken out from the reaction vessel.
  • the hydrogel-like polymer Prior to the step of forming a dry gel by removing water from the hydrogel-like polymer, the hydrogel-like polymer may be coarsely crushed to form a crushed product containing a structure having a small size to some extent. .. By forming the crushed product, water can be efficiently removed.
  • the structure constituting the coarsely crushed product can be, for example, an elongated structure, a granular structure (particle), or a combination thereof.
  • the crushed product may contain a plurality of structures having a shape capable of passing through a circular hole having a diameter of 10 mm or 7 mm.
  • the elongated structure may be bent, and if the maximum width thereof is 10 mm or less, it can be said that the elongated structure has a shape capable of passing through a circular hole having a diameter of 10 mm.
  • the granular structure (particle) may be irregular or may have a shape that allows it to pass through a circular hole having a diameter of 10 mm while changing its direction.
  • the coarsening apparatus for coarsely crushing the hydrogel-like polymer include kneaders (for example, pressurized kneaders, double-armed kneaders), meat choppers, cutter mills, and pharmacomills.
  • the water content of the dry gel containing the polymer obtained by drying may be, for example, 20% by mass or less, 10% by mass or less, or 5% by mass or less.
  • the water content of the dry gel here means the ratio of the water content in the polymer particles based on the total mass of the dry gel containing water.
  • the drying method may be a general method such as natural drying, heat drying, blast drying, freeze drying or a combination thereof.
  • the crushed product may be dried under normal pressure or reduced pressure.
  • the heating temperature for drying can be set within a range in which the progress of the cross-linking reaction by the latent cross-linking agent is suppressed. Specifically, the heating temperature for drying may be 80 ° C. or higher and lower than 160 ° C., or 130 ° C. or higher and 150 ° C. or lower in order to efficiently remove water.
  • a powder of polymer particles containing a polymer and a cross-linking agent is formed.
  • the crushing method is not particularly limited.
  • a dry gel can be crushed using a crusher such as a centrifugal crusher, a roller mill, a stamp mill, a jet mill, a high-speed rotary crusher, and a container-driven mill.
  • a crusher such as a centrifugal crusher, a roller mill, a stamp mill, a jet mill, a high-speed rotary crusher, and a container-driven mill.
  • a dry gel that is moderately soft as compared with the case where the polymer is strongly crosslinked by crosslinking during the polymerization reaction is formed, thereby producing fine particles in the step of crushing the dry gel. It is presumed that it can be suppressed.
  • the powder of the polymer particles obtained by pulverization may be classified.
  • Classification means an operation of dividing a particle group (powder) into two or more particle groups having different particle size distributions. A part of the powder of the polymer particles after the classification may be pulverized and classified again.
  • the classification method is not particularly limited, but may be, for example, screen classification or wind power classification.
  • 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 medium particle size of the powder of the polymer particles obtained by pulverization and, if necessary, classification may be, for example, 200 to 500 ⁇ m or 300 to 500 ⁇ m.
  • the particle size distribution may be adjusted by mixing two or more powders having different medium particle diameters obtained by classification.
  • Centrifuge retention capacity (CRC) of polymer particles after drying and before post-crosslinking is 25 g / g or more, 30 g / g or more, 35 g / g or more, 39 g / g or more, 44 g / g or more, or 49 g / g. It may be the above.
  • CRC Centrifuge retention capacity
  • the upper limit of CRC is not particularly limited, but may be, for example, 60 g / g or less, or 55 g / g or less.
  • the centrifuge holding capacity (CRC) of the polymer particles after drying and before post-crosslinking may be 60 g / g or less at 25 g / g or more, or 55 g / g or less, and 60 g / g at 30 g / g or more. Below, or 55 g / g or less, 35 g / g or more and 60 g / g or less, or 55 g / g or less, 39 g / g or more and 60 g / g or less, or 55 g / g or less.
  • the CRC is a value measured by sieving the powder of the polymer particles using a sieve having an opening of 850 ⁇ m and using the powder of the fraction that has passed through the sieve having an opening of 850 ⁇ m.
  • the powder of the polymer particles is heated for post-crosslinking.
  • the powder of the polymer particles containing the latent cross-linking agent may be heated alone, and the powder of the polymer particles containing the latent cross-linking agent and the solution containing the surface cross-linking agent prepared separately from the latent cross-linking agent may be used.
  • the mixture may be heated. By heating the powder of the polymer particles alone, the formation of coarse particles can be suppressed more effectively.
  • the heating temperature and heating time for post-crosslinking are adjusted so that the crosslinking reaction proceeds appropriately in consideration of the type of the reactive compound used as the latent crosslinking agent and the like.
  • the heating temperature for post-crosslinking may be 160-250 ° C or 190-210 ° C.
  • the heating time for post-crosslinking may be, for example, 5 to 240 minutes.
  • post-crosslinking for example, polymer particles having an efficiently improved absorption ratio under pressure (AAP) can be obtained.
  • AAP absorption ratio under pressure
  • the post-crosslinking index calculated by the following formula may be, for example, 70 or more, 100 or more, 150 or more, 200 or more, or 220 or more, or 300 or less. good.
  • Post-crosslinking index ⁇ (AAP [g / g] after post-crosslinking-AAP [g / g] before post-crosslinking) / AAP [g / g] before post-crosslinking ⁇ ⁇ 100
  • AAP is the absorption ratio under pressure at a pressure of 4.83 kPa (0.7 psi).
  • AAP before post-crosslinking the powder of the polymer particles after drying and pulverization and before post-crosslinking is sieved using a sieve with an opening of 850 ⁇ m, and the powder of the fraction passed through the sieve with an opening of 850 ⁇ m is used. It is a value measured by.
  • the AAP after post-crosslinking is a value measured by sieving the powder of the polymer particles after post-crosslinking using a sieve having an opening of 850 ⁇ m and using the powder of the fraction that has passed through the sieve having an opening of 850 ⁇ m. Is.
  • the polymer particles after post-crosslinking may be further dried or classified if necessary.
  • the polymer particles may be used as they are as the water-absorbent resin particles, or the inorganic particles may be attached to the surface of the polymer particles, for example. That is, the water-absorbent resin particles may contain the polymer particles and the inorganic particles adhering to the surface of the polymer particles.
  • examples of inorganic particles include silica particles such as amorphous silica.
  • the produced water-absorbent resin particles are used to form an absorber constituting an absorbent article such as a diaper, for example.
  • CRC Centrifuge holding capacity
  • a non-woven fabric having a size of 60 mm ⁇ 170 mm (product name: Heat Pack MWA-18, manufactured by Nippon Paper Papylia Co., Ltd.) was folded at a half position in the longitudinal direction to adjust the size to 60 mm ⁇ 85 mm.
  • a 60 mm ⁇ 85 mm non-woven fabric bag was produced by pressure-bonding the non-woven fabrics to each other with a heat seal at a portion having a width of 5 mm along each of the sides extending in the longitudinal direction. 0.2 g of the particles to be measured were precisely weighed and contained inside 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 is submerged in the physiological saline solution by pressing it with a spatula, and in that state, the non-woven fabric bag is immersed in the physiological saline solution for 29 minutes to inside the non-woven fabric bag.
  • the gel was formed with.
  • the non-woven fabric bag was taken out from the physiological saline solution.
  • the non-woven fabric bag taken out was put into a centrifuge (manufactured by Kokusan Co., Ltd., model number: H-122). After the centrifugal force in the centrifuge reached 250 G, the gel in the non-woven fabric bag was dehydrated by continuously applying the centrifugal force to the non-woven fabric bag 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 particles used for the measurement.
  • CRC [g / g] ⁇ (Ma [g] -Mb [g])-Mc [g] ⁇ / Mc [g]
  • the measuring device 110 uses the measuring device 110 shown in FIG. 1, the absorption ratio under pressure (AAP) at a pressure of 4.83 kPa (0.7 psi) was measured.
  • the measuring device 110 is composed of a weight 112, a plastic cylinder 114 having an inner diameter of 60 mm, and a wire mesh 116 having a 400 mesh (opening 38 ⁇ m).
  • the wire mesh 116 closes one opening of the cylinder 114.
  • the cylinder 114 and the wire mesh 116 are arranged so that the wire mesh 116 is horizontal.
  • the weight 112 has a disk portion 112a, a rod-shaped portion 112b extending from the center of the disk portion 112a in a direction perpendicular to the disk portion 112a, and a columnar portion 112c having a through hole in the center.
  • the rod-shaped portion 112b is inserted into the through hole of the cylindrical portion 112c.
  • the disk portion 112a has a diameter substantially equal to the inner diameter of the cylinder 114 so that it can move in the longitudinal direction of the cylinder 114 inside the cylinder 114.
  • the diameter of the cylindrical portion 112c is smaller than the diameter of the disc portion 112a.
  • the weight of the weight 112 is adjusted so that a pressure of 4.83 kPa is applied to the particles to be measured.
  • a glass filter 140 (ISO4793 P-250) having a diameter of 90 mm and a thickness of 7 mm was placed in the center of the bottom surface (diameter 150 mm) of the recess of the stainless steel petri dish 130.
  • a 0.90 mass% sodium chloride aqueous solution (25 ° C. ⁇ 2 ° C.) was added to the stainless steel petri dish 130 until the water surface was at the same height as the upper surface of the glass filter 140.
  • a sheet of filter paper 150 (ADVANTEC Toyo Co., Ltd., product name: (No. 3), thickness 0.23 mm, reserved particle diameter 5 ⁇ m) having a diameter of 90 mm was placed on the glass filter 140.
  • the entire surface of the filter paper 150 was wetted with an aqueous sodium chloride solution to remove the excess aqueous sodium chloride solution. Subsequently, a measuring device 110 in which the measurement target particles 120 before liquid absorption are loaded is placed on the filter paper 150, and the sodium chloride aqueous solution is absorbed by the measurement target particles 120 while pressurizing the measurement target particles 120 at a pressure of 4.83 kPa. I let you.
  • the measuring device 110 was lifted, and the total mass Wb [g] of the measuring device 110 and the particles 120 to be measured after the liquid absorption was measured. From Wa and Wb, the absorption ratio under pressure (AAP) [g / g] was calculated by the following formula.
  • AAP [g / g] (Wb [g] -Wa [g]) /0.90 [g]
  • Example 1 Polymerization An 339.85 g (4.72 mol) of acrylic acid was placed in a separable flask having an internal volume of 2 L. 292.40 g of ion-exchanged water was added to the acrylic acid in the separable flask with stirring. Then, by dropping 295.30 g of 48% by mass sodium hydroxide under an ice bath, a sodium partial neutralized solution of acrylic acid having a monomer concentration of 45% by mass in which 75 mol% of acrylic acid was neutralized was prepared. bottom.
  • One stirrer (diameter 8 mm, length 45 mm, no ring) was placed in the center of the stainless steel vat, and the mixture was stirred with the stirrer to form a uniform liquid polymerization reaction solution.
  • a thermometer for measuring the temperature of the polymerization reaction solution was installed in the center of the stainless steel vat. Then, a tube for nitrogen substitution was inserted into the polymerization reaction solution, and the opening of the stainless steel vat was covered with a polyethylene film. After adjusting the temperature of the polymerization reaction solution to 25 ° C., the reaction system was replaced with nitrogen until the dissolved oxygen amount became 0.1 ppm or less by bubbling nitrogen gas from the tube inserted in the polymerization reaction solution.
  • the polymerization reaction started.
  • the nitrogen replacement tube was pulled out and stirring was stopped.
  • the viscosity of the reaction solution increased with the progress of the polymerization reaction, the polymerization reaction solution gelled, and a hydrogel-like polymer containing water and a crosslinked polymer was formed.
  • the thermometer measuring the temperature of the mixture showed a maximum value of 69 ° C.
  • the crosslinked polymer at this point is mainly crosslinked by PEGDA, and most of the charged EC remains in the hydrogel-like polymer.
  • the stainless steel vat containing the water-containing gel-like polymer was immersed in a water bath at 75 ° C., and the water-containing gel-like polymer was aged in that state for 20 minutes.
  • the hydrogel polymer after coarse crushing and aging was taken out from a stainless steel vat and immediately cut into a width of about 5 cm.
  • the cut water-containing gel polymer was coarsely crushed by a meat chopper (12VR-750SDX manufactured by Kiren Royal Co., Ltd.).
  • the diameter of the hole in the plate located at the outlet of the meat chopper was 6.4 mm.
  • the obtained coarse crushed material was spread over a wire mesh having an opening of 0.8 cm ⁇ 0.8 cm and dried by hot air drying at 150 ° C. for 30 minutes to obtain a dried gel.
  • the dried gel was pulverized using a centrifugal pulverizer (ZM200 manufactured by Retsch, screen diameter 1 mm, 6000 rpm) to obtain a powder of polymer particles.
  • Particle size distribution after crushing 10 g of powder of polymer particles obtained by crushing was used with a continuous fully automatic sonic vibration type sieving measuring instrument (Robot Shifter RPS-205, manufactured by Seishin Corporation) and a JIS standard opening of 850 ⁇ m.
  • Sieves were performed using 600 ⁇ m, 500 ⁇ m, 425 ⁇ m, 300 ⁇ m, 250 ⁇ m and 180 ⁇ m sieves and a saucer. The mass of the particles remaining on each sieve was calculated as a mass percentage with respect to the total amount, and the particle size distribution was obtained.
  • the mass percentages of the particles remaining on each sieve are integrated in order from the one having the largest particle size, and the meshing of the sieve and the integrated value of the mass percentages of the particles remaining on the sieve are calculated.
  • the relationship 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 used as the medium particle size of the polymer particles.
  • the CRC and AAP of the obtained polymer particles were measured.
  • the post-crosslink index was calculated by the following formula.
  • the post-crosslinking index is a numerical value expressing the rate of change of the AAP of the water-absorbent resin particles, which is expected to be improved as the cross-linking progresses, before and after the subsequent cross-linking.
  • a high value of the post-crosslinking index can be regarded as corresponding to the efficient progress of the post-crosslinking reaction.
  • the measurement results are shown in Table 1.
  • Post-crosslinking index ⁇ (AAP [g / g] after post-crosslinking-AAP [g / g] before post-crosslinking) / AAP [g / g] before post-crosslinking ⁇ ⁇ 100
  • Example 2 255.33 g of a partial neutralizing solution of sodium acrylate prepared in the same manner as in Example 1, 43.32 g of ion-exchanged water, and 0.089 g of polyethylene glycol diacrylate (PEGDA) (Nippon Oil Co., Ltd., Blemmer ADE-400A). And 0.46 g of ethylene carbonate (EC) were placed in a fluororesin-coated stainless steel bat.
  • the Stensbat had a rectangular bottom surface with internal dimensions of 155 cm in length and 110 cm in width, and a rectangular opening in 175 cm in length and 130 cm in width.
  • One stirrer (diameter 8 mm, length 45 mm, no ring) was placed in the center of the stainless steel vat, and the mixture was stirred with the stirrer to form a uniform liquid polymerization reaction solution.
  • a thermometer for measuring the temperature of the polymerization reaction solution was installed in the center of the stainless steel vat. Then, a tube for nitrogen substitution was inserted into the polymerization reaction solution, and the opening of the stainless steel vat was covered with a polyethylene film. After adjusting the temperature of the polymerization reaction solution to 25 ° C., the reaction system was replaced with nitrogen until the dissolved oxygen amount became 0.1 ppm or less by bubbling nitrogen gas from the tube inserted in the polymerization reaction solution. 1.
  • 1.06 g of a hydrogen peroxide aqueous solution having a concentration of 0.35 mass% were added to a syringe (HENKE SASS WOLF, 3 mL). It was added dropwise to the polymerization reaction solution in the stainless steel bat in order using a disposable syringe (injection needle manufactured by Telmo Co., Ltd.).
  • the polymerization reaction started immediately after dropping the hydrogen peroxide aqueous solution. At 3 minutes after the completion of dropping the hydrogen peroxide solution, the thermometer measuring the temperature of the polymerization reaction solution showed a maximum value of 106 ° C. One minute after the completion of dropping the hydrogen peroxide solution, the nitrogen replacement tube was pulled out and stirring was stopped. After the viscosity of the reaction solution increased with the progress of the polymerization reaction, the polymerization reaction solution gelled, and a hydrogel-like polymer containing water and a crosslinked polymer was formed. It is considered that the crosslinked polymer at this point is mainly crosslinked by PEGDA, and most of the charged EC remains in the hydrogel-like polymer.
  • the stainless steel vat containing the water-containing gel-like polymer was immersed in a water bath at 75 ° C., and the water-containing gel-like polymer was aged in that state for 20 minutes. Then, the hydrogel polymer was taken out from the stainless steel vat and immediately cut into a width of about 5 cm.
  • the cut water-containing gel polymer was coarsely crushed by a meat chopper (12VR-750SDX manufactured by Kiren Royal Co., Ltd.). The diameter of the hole in the plate located at the outlet of the meat chopper was 6.4 mm.
  • the obtained coarse crushed product was spread out on a wire mesh having an opening of 0.8 cm ⁇ 0.8 cm and dried by hot air drying at 150 ° C. for 30 minutes to obtain a dried product.
  • the dried product was pulverized using a centrifugal pulverizer (Retsch, ZM200, screen diameter 1 mm, 6000 rpm).
  • the medium particle size of the polymer particles obtained by pulverization and the mass percentage (180 ⁇ m pass) of the particles that passed through the sieve of 180 ⁇ m were measured by the same sieving as in Example 1.
  • the powder obtained by pulverization was sieved by shaking for 1 minute using a sieve having an opening of 850 ⁇ m.
  • 94.41 g of polymer particles that had passed through a sieve having an opening of 850 ⁇ m were recovered.
  • the CRC and AAP of the recovered polymer particles were measured.
  • Example 3 The powder of the polymer particles after pulverization and before post-crosslinking was obtained in the same manner as in Example 2 except that 0.40 g of propylene glycol (PG) was used instead of 0.46 g of ethylene carbonate (EC).
  • PG propylene glycol
  • EC ethylene carbonate
  • the powder obtained by pulverization was sieved by shaking for 1 minute using a sieve having an opening of 850 ⁇ m.
  • 93.96 g of polymer particles that had passed through a sieve having an opening of 850 ⁇ m were recovered.
  • the CRC and AAP of the recovered polymer particles were measured.
  • the post-crosslinking reaction mainly by PG was allowed to proceed.
  • the polymer particles after post-crosslinking were classified with a sieve having an opening of 850 ⁇ m to obtain 15.0 g of polymer particles (water-absorbent resin particles) that had passed through a sieve having an opening of 850 ⁇ m.
  • the mass percentage (850 ⁇ m on) of the particles remaining on the 850 ⁇ m sieve was 0%.
  • the CRC and AAP of the obtained polymer particles were measured, and the post-crosslinking index was calculated.
  • Example 4 The powder of the polymer particles after pulverization and before post-crosslinking was obtained in the same manner as in Example 2 except that 0.56 g of diethylene glycol (DEG) was used instead of 0.46 g of ethylene carbonate (EC).
  • DEG diethylene glycol
  • EC ethylene carbonate
  • the powder obtained by pulverization was sieved by shaking for 1 minute using a sieve having an opening of 850 ⁇ m.
  • 95.93 g of polymer particles that had passed through a sieve having an opening of 850 ⁇ m were recovered.
  • the CRC and AAP of the recovered polymer particles were measured.
  • the post-crosslinking reaction mainly by DEG was allowed to proceed.
  • the polymer particles after post-crosslinking were classified with a sieve having an opening of 850 ⁇ m to obtain 15.0 g of polymer particles (water-absorbent resin particles) that had passed through a sieve having an opening of 850 ⁇ m.
  • the mass percentage (850 ⁇ m on) of the particles remaining on the 850 ⁇ m sieve was 0%.
  • the CRC and AAP of the obtained polymer particles were measured, and the post-crosslinking index was calculated.
  • Example 1 The powder of the polymer particles after pulverization and before post-crosslinking was obtained in the same manner as in Example 1 except that 0.46 g of ethylene carbonate (EC) was not used.
  • the powder obtained by pulverization was sieved by shaking for 1 minute using a sieve having an opening of 850 ⁇ m. 101.68 g of polymer particles that had passed through a sieve having an opening of 850 ⁇ m were recovered. The CRC and AAP of the recovered polymer particles were measured.
  • 15.0 g of the obtained polymer particles were heated at 200 ° C. for 60 minutes.
  • a sieve having an opening of 850 ⁇ m 15.0 g of polymer particles (water-absorbent resin particles) passing through the sieve having an opening of 850 ⁇ m were obtained.
  • the mass percentage (850 ⁇ m on) of the particles remaining on the 850 ⁇ m sieve was 0%.
  • the CRC and AAP of the obtained polymer particles were measured, and the post-crosslinking index was calculated.
  • Comparative Example 2 15 g of the polymer particles after passing through the 850 ⁇ m sieve obtained in Comparative Example 1 and before cross-linking were mixed with a surface cross-linking agent solution consisting of 0.06 g of ethylene carbonate (EC) and 0.49 g of deionized water. Post-crosslinking with a surface crosslinking agent (EC) was allowed to proceed by heating the formed mixture at 200 ° C. for 60 minutes. The polymer particles after post-crosslinking were classified with a sieve having an opening of 850 ⁇ m to obtain 12.7 g of polymer particles (water-absorbent resin particles) that had passed through a sieve having an opening of 850 ⁇ m. The mass of the particles remaining on the 850 ⁇ m sieve was 2.3 g, and the mass percentage (850 ⁇ m on) was 15.3%. The CRC and AAP of the obtained polymer particles were measured, and the post-crosslinking index was calculated.
  • EC ethylene carbonate
  • Example 3 The powder of the polymer particles after pulverization and before post-crosslinking was obtained in the same manner as in Example 2 except that 0.46 g of ethylene carbonate (EC) was not used.
  • the medium particle size of the polymer particles obtained by pulverization and the mass percentage (180 ⁇ m pass) of the particles passed through a 180 ⁇ m sieve were measured by the same sieving as in Example 1.
  • the powder obtained by pulverization was sieved by shaking for 1 minute using a sieve having an opening of 850 ⁇ m.
  • 92.20 g of polymer particles that had passed through a sieve having an opening of 850 ⁇ m were recovered.
  • the CRC and AAP of the recovered polymer particles were measured.
  • 15.0 g of the obtained polymer particles were heated at 200 ° C. for 60 minutes.
  • a sieve having an opening of 850 ⁇ m 15.0 g of polymer particles (water-absorbent resin particles) passing through the sieve having an opening of 850 ⁇ m were obtained.
  • the mass percentage (850 ⁇ m on) of the particles remaining on the 850 ⁇ m sieve was 0%.
  • Comparative Example 4 15 g of the polymer particles after passing through the 850 ⁇ m sieve obtained in Comparative Example 3 and before cross-linking were mixed with a surface cross-linking agent solution consisting of 0.06 g of ethylene carbonate (EC) and 0.49 g of deionized water. Post-crosslinking with a surface crosslinking agent (EC) was allowed to proceed by heating the formed mixture at 200 ° C. for 60 minutes. The polymer particles after the post-crosslinking were classified with a sieve having an opening of 850 ⁇ m to obtain 13.3 g of the polymer particles (water-absorbent resin particles) that had passed through the sieve having an opening of 850 ⁇ m. The mass of the particles remaining on the 850 ⁇ m sieve was 1.7 g, and the mass percentage (850 ⁇ m on) was 11.3%. The CRC and AAP of the obtained polymer particles were measured, and the post-crosslinking index was calculated.
  • EC ethylene carbonate
  • Comparative Example 5 The weight after cross-linking after passing through a sieve having an opening of 850 ⁇ m in the same manner as in Comparative Example 4 except that a surface cross-linking agent solution consisting of 0.12 g of ethylene carbonate (EC) and 0.43 g of deionized water was used. 13.1 g of coalesced particles (water-absorbent resin particles) were obtained. The mass of the particles remaining on the 850 ⁇ m sieve was 1.9 g, and the mass percentage (850 ⁇ m on) was 12.7%. The CRC and AAP of the obtained polymer particles were measured, and the post-crosslinking index was calculated.
  • EC ethylene carbonate
  • Example 6 The weight after pulverization and before post-crosslinking was the same as in Example 2 except that the amount of polyethylene glycol diacrylate (PEGDA) added to the polymerization reaction solution was changed to 2.72 g without using ethylene carbonate (EC). A powder of coalesced particles was obtained. The medium particle size of the polymer particles obtained by pulverization and the mass percentage (180 ⁇ m pass) of the particles passed through the 180 ⁇ m sieve were measured by the same sieving as in Example 1.
  • PEGDA polyethylene glycol diacrylate
  • the powder obtained by pulverization was sieved by shaking for 1 minute using a sieve having an opening of 850 ⁇ m.
  • 112.64 g of polymer particles that had passed through a sieve having an opening of 850 ⁇ m were recovered.
  • the CRC and AAP of the recovered polymer particles were measured.
  • 15.0 g of the obtained polymer particles were heated at 200 ° C. for 60 minutes.
  • a sieve having an opening of 850 ⁇ m 15.0 g of polymer particles (water-absorbent resin particles) passing through the sieve having an opening of 850 ⁇ m were obtained.
  • the mass percentage (850 ⁇ m on) of the particles remaining on the 850 ⁇ m sieve was 0%.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Organic Chemistry (AREA)
  • Health & Medical Sciences (AREA)
  • Medicinal Chemistry (AREA)
  • Polymers & Plastics (AREA)
  • Analytical Chemistry (AREA)
  • Addition Polymer Or Copolymer, Post-Treatments, Or Chemical Modifications (AREA)

Abstract

L'invention concerne un procédé de production de particules de résine absorbant l'eau comprenant des particules de polymère. Le procédé comprend une étape dans laquelle un gel sec comprenant un polymère et un agent de réticulation est pulvérisé pour former une poudre de particules de polymère et une étape dans laquelle la poudre est chauffée pour réticuler le polymère par réaction avec l'agent de réticulation.
PCT/JP2021/036621 2020-10-07 2021-10-04 Procédé de production de particules de résine absorbant l'eau WO2022075258A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP2022555468A JPWO2022075258A1 (fr) 2020-10-07 2021-10-04

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2020-169676 2020-10-07
JP2020169676 2020-10-07

Publications (1)

Publication Number Publication Date
WO2022075258A1 true WO2022075258A1 (fr) 2022-04-14

Family

ID=81126046

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/JP2021/036621 WO2022075258A1 (fr) 2020-10-07 2021-10-04 Procédé de production de particules de résine absorbant l'eau

Country Status (2)

Country Link
JP (1) JPWO2022075258A1 (fr)
WO (1) WO2022075258A1 (fr)

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2011111855A1 (fr) * 2010-03-12 2011-09-15 株式会社日本触媒 Procédé de fabrication d'une résine absorbant l'eau
WO2011115221A1 (fr) * 2010-03-17 2011-09-22 株式会社日本触媒 Procédé de production d'une résine absorbante
JP2017517620A (ja) * 2014-05-08 2017-06-29 ビーエーエスエフ ソシエタス・ヨーロピアＢａｓｆ Ｓｅ 吸水性ポリマー粒子の製造方法
WO2019221154A1 (fr) * 2018-05-16 2019-11-21 株式会社日本触媒 Procédé de production de particules de résine absorbant l'eau
JP2020094165A (ja) * 2018-12-12 2020-06-18 住友精化株式会社 吸水性樹脂粒子
WO2020184395A1 (fr) * 2019-03-08 2020-09-17 住友精化株式会社 Particules de resine hydro-absorbantes, procede de production de celles-ci, corps absorbant, article absorbant ainsi que procede de regulation de la vitesse de penetration

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2011111855A1 (fr) * 2010-03-12 2011-09-15 株式会社日本触媒 Procédé de fabrication d'une résine absorbant l'eau
WO2011115221A1 (fr) * 2010-03-17 2011-09-22 株式会社日本触媒 Procédé de production d'une résine absorbante
JP2017517620A (ja) * 2014-05-08 2017-06-29 ビーエーエスエフ ソシエタス・ヨーロピアＢａｓｆ Ｓｅ 吸水性ポリマー粒子の製造方法
WO2019221154A1 (fr) * 2018-05-16 2019-11-21 株式会社日本触媒 Procédé de production de particules de résine absorbant l'eau
JP2020094165A (ja) * 2018-12-12 2020-06-18 住友精化株式会社 吸水性樹脂粒子
WO2020184395A1 (fr) * 2019-03-08 2020-09-17 住友精化株式会社 Particules de resine hydro-absorbantes, procede de production de celles-ci, corps absorbant, article absorbant ainsi que procede de regulation de la vitesse de penetration

Also Published As

Publication number Publication date
JPWO2022075258A1 (fr) 2022-04-14

Similar Documents

Publication Publication Date Title
US11020726B2 (en) Super absorbent polyacrylic acid (salt)-based resin powder, method for manufacturing same, and method for evaluating same
US8875415B2 (en) Method for drying granular water-containing gel-like cross-linked polymer
KR100819613B1 (ko) 수분 흡수제와 그 제조방법
CN111433261B (zh) 超吸收性聚合物组合物及其制备方法
JP2000063527A (ja) 含水ゲル状架橋重合体の細粒化方法
WO2021117781A1 (fr) Particules de résine absorbant l'eau et procédé de production de particules de résine absorbant l'eau
WO2014021432A1 (fr) Procédé de production de résine absorbant l'eau à base de (sel) d'acide polyacrylique
JPWO2013073682A1 (ja) ポリアクリル酸（塩）系吸水性樹脂の製造方法
JP4749679B2 (ja) 吸水性樹脂およびその製造方法
JP2018162455A (ja) 吸水性樹脂の製造方法
WO2022075258A1 (fr) Procédé de production de particules de résine absorbant l'eau
JP2005081204A (ja) 吸水性樹脂組成物の製造方法
JP2020505477A (ja) 高吸水性樹脂およびその製造方法
WO2021187326A1 (fr) Procédé de production de particules de résine absorbant l'eau
WO2021049451A1 (fr) Procédé pour la production de particules de résine pouvant absorber l'eau
WO2020241123A1 (fr) Procédé de production d'un absorbant d'eau et résine absorbant l'eau à base de (sel de) poly(acide acrylique)
WO2022025122A1 (fr) Procédé de production de particules de résine absorbant l'eau
WO2022181452A1 (fr) Procédé de production de particules de résine absorbant l'eau
JP6649441B2 (ja) 使い捨てカイロ用吸水剤および使い捨てカイロの製造方法
WO2022025003A1 (fr) Particules de résine absorbant l'eau et procédé de production de particules de résine absorbant l'eau
WO2021235524A1 (fr) Procédé de production de particules de résine absorbant l'eau
WO2021049467A1 (fr) Procédé de production de particules de polymère réticulé et gel de polymère réticulé
WO2022118800A1 (fr) Particules de résine absorbant l'eau, corps absorbant et article absorbant
WO2021246244A1 (fr) Procédé de production de particule de résine absorbant d'eau
JP2022087997A (ja) 吸水性樹脂粒子を製造する方法

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 21877557

Country of ref document: EP

Kind code of ref document: A1

ENP Entry into the national phase

Ref document number: 2022555468

Country of ref document: JP

Kind code of ref document: A

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 21877557

Country of ref document: EP

Kind code of ref document: A1