WO2021246243A1 - Procédé de production de particules polymères réticulées et procédé de production de particules de résine absorbant l'eau - Google Patents

Procédé de production de particules polymères réticulées et procédé de production de particules de résine absorbant l'eau Download PDF

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WO2021246243A1
WO2021246243A1 PCT/JP2021/019821 JP2021019821W WO2021246243A1 WO 2021246243 A1 WO2021246243 A1 WO 2021246243A1 JP 2021019821 W JP2021019821 W JP 2021019821W WO 2021246243 A1 WO2021246243 A1 WO 2021246243A1
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crosslinked polymer
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mass
particles
polymer particles
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PCT/JP2021/019821
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Japanese (ja)
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萌 西田
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住友精化株式会社
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Priority to JP2022528761A priority Critical patent/JPWO2021246243A1/ja
Publication of WO2021246243A1 publication Critical patent/WO2021246243A1/fr

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    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
    • A61F13/00—Bandages or dressings; Absorbent pads
    • A61F13/15—Absorbent pads, e.g. sanitary towels, swabs or tampons for external or internal application to the body; Supporting or fastening means therefor; Tampon applicators
    • 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
    • C08F6/00—Post-polymerisation treatments
    • C08F6/06—Treatment of polymer solutions
    • 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 invention relates to a method for producing crosslinked polymer particles and a method for producing water-absorbent resin particles.
  • an absorber containing water-absorbent resin particles has been used as an absorbent article for absorbing a liquid (for example, urine) containing water as a main component (see, for example, Patent Document 1 below).
  • the water-absorbent resin particles can be obtained, for example, by crushing the crosslinked polymer to obtain crosslinked polymer particles and then subjecting the crosslinked polymer particles to crosslinking.
  • the water-absorbent resin particles in the absorber are required to have high water absorption and excellent liquid diffusivity.
  • the liquid diffusibility generally tends to decrease as the amount of fine powder (content of fine powder) in the water-absorbent resin particles increases. That is, the fine powder in the water-absorbent resin particles tends to block the path for the liquid to diffuse when swollen, and tends to cause so-called "gel blocking".
  • gel blocking When the water-absorbent resin particles cause gel blocking, the diffusivity of the liquid in the absorber deteriorates, so that the original performance of the absorber is not sufficiently exhibited and the amount of liquid reversion increases. Therefore, it is required that the amount of fine powder in the crosslinked polymer particles for obtaining the water-absorbent resin particles is small.
  • One aspect of the present invention is a step of obtaining a crosslinked polymer by polymerizing a monomer, a drying step of drying the crosslinked polymer, and a crushing step of crushing the crosslinked polymer after the drying step.
  • the crosslinked polymer particles have a temperature difference of more than 0 ° C. and 100 ° C. or less between the surface temperature of the crosslinked polymer at the end of the drying step and the surface temperature of the crosslinked polymer at the start of the crushing step. Provides a manufacturing method for.
  • crosslinked polymer particles having a small amount of fine powder can be obtained.
  • Another aspect of the present invention provides a method for producing water-absorbent resin particles, which comprises a step of performing cross-linking on the cross-linked polymer particles obtained by the above-mentioned method for producing cross-linked polymer particles.
  • Water-soluble means that it exhibits a solubility in water of 5% by mass or more at 25 ° C.
  • the materials exemplified in the present specification may be used alone or in combination of two or more.
  • the content of 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.
  • “content of (meth) acrylic acid compound” means acrylic acid, acrylic acid salt, methacrylic acid and methacrylic acid. It means the total amount of acid salt.
  • Room temperature means 25 ° C ⁇ 2 ° C.
  • the water content, medium particle size and particle size distribution may be the water content, medium particle size and particle size distribution at room temperature.
  • the method for producing crosslinked polymer particles according to the present embodiment includes a polymerization step of obtaining a crosslinked polymer by polymerizing a monomer, a drying step of drying the crosslinked polymer, and a pulverizing of the crosslinked polymer after the drying step.
  • a crushing step is provided, and the temperature difference ⁇ T (T1-T2) between the surface temperature T1 of the crosslinked polymer at the end of the drying step and the surface temperature T2 of the crosslinked polymer at the start of the crushing step exceeds 0 ° C. 100. It is below ° C.
  • crosslinked polymer particles having a small amount of fine powder (content of fine powder (particles having a particle size of more than 0 ⁇ m and less than 250 ⁇ m) based on the mass). It is possible to obtain crosslinked polymer particles (crosslinked polymer particle group) in which the mass ratio (fine particle abundance ratio) of particles having a particle diameter of less than 250 ⁇ m to particles having a particle diameter of 250 ⁇ m or more and less than 850 ⁇ m is 50% by mass or less.
  • the cause is not limited to the content.
  • the method for adjusting the amount of fine powder in the crosslinked polymer particles is a step of obtaining a crosslinked polymer by polymerizing a monomer, a drying step of drying the crosslinked polymer, and a step of drying the crosslinked polymer after the drying step.
  • a crushing step for crushing is provided, and the amount of fine powder in the crosslinked polymer particles is adjusted based on the temperature difference between the surface temperature of the crosslinked polymer at the end of the drying step and the surface temperature of the crosslinked polymer at the start of the crushing step. ..
  • the crosslinked polymer particles according to the present embodiment are the crosslinked polymer particles obtained by the method for producing the crosslinked polymer particles according to the present embodiment.
  • the method for producing crosslinked polymer particles according to the present embodiment is a method for producing crosslinked polymer particles capable of obtaining water-absorbent resin particles by subjecting crosslinking. According to the method for producing crosslinked polymer particles according to the present embodiment, it is possible to obtain crosslinked polymer particles capable of obtaining water-absorbent resin particles having excellent liquid diffusivity in an absorber.
  • the method for producing water-absorbent resin particles according to the present embodiment includes a cross-linking step of performing cross-linking on the cross-linked polymer particles obtained by the method for producing cross-linked polymer particles according to the present embodiment.
  • a crosslinked polymer is obtained by polymerizing the monomer.
  • a crosslinked polymer may be obtained by polymerizing a monomer composition containing a monomer.
  • the crosslinked polymer obtained in the polymerization step may be a crosslinked polymer gel.
  • the monomer composition may contain water, an organic solvent, or the like.
  • the monomer composition may be a monomer aqueous solution.
  • Examples of the polymerization method of the monomer composition include an aqueous solution polymerization method and a bulk polymerization method. Among these, the aqueous solution polymerization method is preferable from the viewpoint of easily obtaining good water absorption performance and easily increasing productivity.
  • the aqueous solution polymerization method is used as an example of the polymerization method will be described.
  • the monomer may contain an ethylenically unsaturated monomer and may contain a water-soluble ethylenically unsaturated monomer.
  • the ethylenically unsaturated monomer include unsaturated carboxylic acids such as (meth) acrylic acid, maleic acid, maleic anhydride and fumaric acid, and carboxylic acid-based monomers such as salts thereof; (meth) acrylamide, Nonionic monomers such as N, N-dimethyl (meth) acrylamide, 2-hydroxyethyl (meth) acrylate, N-methylol (meth) acrylamide, polyethylene glycol mono (meth) acrylate; N, N-diethylaminoethyl ( Amino group-containing unsaturated monomers such as meth) acrylate, N, N-diethylaminopropyl (meth) acrylate, diethylaminopropyl (meth) acrylamide, and quaternary products thereof; vinyl
  • the ethylenically unsaturated monomer can contain at least one (meth) acrylic acid compound selected from the group consisting of (meth) acrylic acid and salts thereof.
  • the ethylenically unsaturated monomer may contain both (meth) acrylic acid and a salt of (meth) acrylic acid.
  • Examples of the salt of unsaturated carboxylic acid ((meth) acrylic acid, etc.) include alkali metal salts (sodium salt, potassium salt, etc.), alkaline earth metal salts (calcium salt, etc.) and the like.
  • the ethylenically unsaturated monomer having an acid group may have an acid group neutralized in advance with an alkaline neutralizing agent.
  • alkaline neutralizing agent include alkali metal salts such as sodium hydroxide, sodium carbonate, sodium hydrogencarbonate, potassium hydroxide and potassium carbonate; ammonia and the like.
  • the alkaline neutralizer may be used in the form of an aqueous solution in order to simplify the neutralization operation.
  • 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 is from the viewpoint that good water absorption performance can be easily obtained by increasing the osmotic pressure, from the viewpoint of enhancing safety, and from the viewpoint of increasing the excess alkaline neutralizer. From the viewpoint of suppressing defects due to existence, 10 to 100 mol%, 30 to 90 mol%, 40 to 85 mol%, or 50 to 80 mol% is preferable.
  • the "neutralization degree” is the neutralization degree for all the acid groups of the ethylenically unsaturated monomer.
  • the content of the monomer (for example, (meth) acrylic acid compound) is preferably in the following range based on the total mass of the monomer composition.
  • the content of the monomer is preferably 10% by mass or more, 15% by mass or more, 20% by mass or more, 25% by mass or more, 30% by mass or more, or 35% by mass or more from the viewpoint of easily increasing productivity.
  • the content of the monomer is preferably 60% by mass or less, 55% by mass or less, 50% by mass or less, less than 50% by mass, 45% by mass or less, or 40% by mass or less from the viewpoint of easily enhancing the water absorption performance. From these viewpoints, the content of the monomer is preferably 10 to 60% by mass.
  • the content of the structural unit derived from the (meth) acrylic acid compound is in each of the above-mentioned ranges regarding the content of the monomer with respect to the total mass of the crosslinked polymer particles. It is preferable to have.
  • the content of the (meth) acrylic acid compound is the total amount of the monomers contained in the monomer composition and / or the total amount of the ethylenically unsaturated monomers contained in the monomer composition. The following range is preferable with reference to.
  • the content of the (meth) acrylic acid compound is preferably 50 mol% or more, 70 mol% or more, 90 mol% or more, 95 mol% or more, 97 mol% or more, or 99 mol% or more.
  • the monomer contained in the monomer composition and / or the ethylenically unsaturated monomer contained in the monomer composition is substantially composed of a (meth) acrylic acid compound (substantially).
  • 100 mol% of the monomer contained in the monomer composition and / or the ethylenically unsaturated monomer contained in the monomer composition is a (meth) acrylic acid compound). May be.
  • the monomer composition may contain a polymerization initiator.
  • the polymerization of the monomer contained in the monomer composition may be started by adding a polymerization initiator to the monomer composition and, if necessary, heating, irradiating with light or the like.
  • the polymerization initiator include a photopolymerization initiator, a radical polymerization initiator and the like, and a water-soluble radical polymerization initiator is preferable.
  • the polymerization initiator preferably contains at least one selected from the group consisting of azo compounds and peroxides from the viewpoint of easily enhancing water absorption performance.
  • Examples of the azo compound include 2,2'-azobis [2- (N-phenylamidino) propane] dihydrochloride and 2,2'-azobis ⁇ 2- [N- (4-chlorophenyl) amidino] propane ⁇ dihydrochloride.
  • the azo compounds are 2,2'-azobis (2-methylpropionamide) dihydrochloride, 2,2'-azobis (2-amidinopropane) dihydrochloride, 2 from the viewpoint that good water absorption performance can be easily obtained.
  • Peroxides include persulfates such as potassium persulfate, ammonium persulfate, sodium persulfate; methyl ethyl ketone peroxide, methyl isobutyl ketone peroxide, di-t-butyl peroxide, t-butyl cumyl peroxide, t-butyl. Examples thereof include organic peroxides such as peroxyacetate, t-butylperoxyisobutyrate, and t-butylperoxypivalate.
  • the peroxide is composed of potassium persulfate, ammonium persulfate, and sodium persulfate from the viewpoint of easily obtaining good water absorption performance and easily reducing unreacted monomers contained in the water-absorbent resin particles. It is preferable to include at least one selected from the group.
  • the content of the polymerization initiator is preferably in the following range with respect to 1 mol of the ethylenically unsaturated monomer (for example, (meth) acrylic acid compound).
  • the content of the polymerization initiator is 0.001 mmol or more, 0.005 mmol or more, from the viewpoint of easily enhancing the water absorption performance and easily reducing the amount of unreacted monomers contained in the water-absorbent resin particles. It is preferably 0.01 mmol or more, 0.05 mmol or more, 0.1 mmol or more, or 0.15 mmol or more.
  • the content of the polymerization initiator is 5 mmol or less, 4 mmol or less, 2 mmol or less, 1 mmol or less, 0.9 mmol or less, from the viewpoint of easily improving the water absorption performance and avoiding a rapid polymerization reaction. It is preferably 0.7 mmol or less, 0.5 mmol or less, 0.4 mmol or less, or 0.3 mmol or less. From these viewpoints, the content of the polymerization initiator is preferably 0.001 to 5 mmol.
  • the monomer composition may contain a reducing agent.
  • the reducing agent include sodium sulfite, sodium hydrogen sulfite, ferrous sulfate, L-ascorbic acid and the like.
  • a polymerization initiator and a reducing agent may be used in combination.
  • the monomer composition may contain an oxidizing agent.
  • the oxidizing agent include hydrogen peroxide, sodium perborate, perphosphoric acid and salts thereof, potassium permanganate and the like.
  • the monomer composition may contain an internal cross-linking agent.
  • the obtained cross-linking polymer can have a cross-linking structure by the internal cross-linking agent in addition to the self-cross-linking structure by the polymerization reaction as the internal cross-linking structure.
  • Examples of the internal cross-linking agent include compounds having two or more reactive functional groups (for example, polymerizable unsaturated groups).
  • Examples of the internal cross-linking agent include di or tri (meth) acrylic acid esters of polyols such as (poly) ethylene glycol, (poly) propylene glycol, trimethylolpropane, glycerin polyoxyethylene glycol, polyoxypropylene glycol, and (poly) glycerin.
  • unsaturated polyesters obtained by reacting the above polyol with unsaturated acids maleic acid, fumaric acid, etc.
  • unsaturated acids maleic acid, fumaric acid, etc.
  • the internal cross-linking agent is (poly) ethylene glycol diglycidyl ether, (poly) propylene glycol diglycidyl ether, (poly) glycerin triglycidyl ether, from the viewpoint of easily enhancing water absorption performance and excellent reactivity at low temperature. And, it is preferable to contain at least one selected from the group consisting of (poly) glycerin diglycidyl ether.
  • the content of the internal cross-linking agent is preferably in the following range with respect to 1 mol of the ethylenically unsaturated monomer (for example, (meth) acrylic acid compound).
  • the content of the internal cross-linking agent is 0.001 mmol or more, 0.005 mmol or more, 0.01 mmol or more, 0.05 mmol or more, 0.07 mmol or more, 0 from the viewpoint that good water absorption performance can be easily obtained. .09 mmol or more, 0.1 mmol or more, 0.11 mmol or more, or 0.13 mmol or more is preferable.
  • the content of the internal cross-linking agent is 5 mmol or less, 4.5 mmol or less, 4 mmol or less, 3.5 mmol or less, 3 mmol or less, 2.5 mmol or less, 2 from the viewpoint that good water absorption performance can be easily obtained. Millimole or less, 1.5 mmol or less, 1 mmol or less, 0.9 mmol or less, 0.8 mmol or less, 0.7 mmol or less, 0.5 mmol or less, 0.4 mmol or less, or 0.3 mmol or less Is preferable. From these viewpoints, the content of the internal cross-linking agent is preferably 0.001 to 5 mmol.
  • the monomer composition may contain additives such as a chain transfer agent, a thickener, and an inorganic filler as components different from the above-mentioned components.
  • a chain transfer agent include thiols, thiol acids, secondary alcohols, hypophosphorous acid, phosphorous acid, achlorine and the like.
  • the thickener include carboxymethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, methyl cellulose, polyethylene glycol, polyacrylic acid, polyacrylic acid neutralizer, polyacrylamide and the like.
  • the inorganic filler include metal oxides, ceramics, and viscous minerals.
  • a polymerization method for aqueous solution polymerization As a polymerization method for aqueous solution polymerization, a static polymerization method in which the monomer composition is polymerized without stirring (for example, a static state); a stirring polymerization method in which the monomer composition is polymerized while stirring in a reaction apparatus. And so on.
  • a static polymerization method when the polymerization is completed, a single block-shaped gel occupying substantially the same volume as the monomer composition present in the reaction vessel can be obtained.
  • the form of polymerization may be batch, semi-continuous, continuous or the like.
  • the polymerization reaction can be carried out while continuously supplying the monomer composition to the continuous polymerization apparatus to continuously obtain a gel.
  • the polymerization temperature varies depending on the polymerization initiator used, but from the viewpoint of rapidly advancing the polymerization, increasing the productivity by shortening the polymerization time, and removing the heat of polymerization to facilitate the smooth reaction, 0 to 0 to It is preferably 130 ° C or 10 to 110 ° C.
  • the polymerization time is appropriately set depending on the type and amount of the polymerization initiator used, the reaction temperature and the like, but is preferably 1 to 200 minutes or 5 to 100 minutes.
  • the crosslinked polymer obtained in the polymerization step is dried to obtain a dried product.
  • the crosslinked polymer dried in the drying step may be a crosslinked polymer that has been treated (for example, a coarse crushing treatment described later) between the polymerization step and the drying step.
  • a dried product can be obtained by removing the liquid component (water or the like) in the crosslinked polymer by heating and / or blowing air.
  • the drying method may be natural drying, heat drying (for example, hot air drying), vacuum drying or the like.
  • the drying temperature is preferably a temperature range described later as a preferable range of the surface temperature T1 from the viewpoint of easily obtaining crosslinked polymer particles having a small amount of fine powder.
  • the drying time may be 1 to 60 minutes, 5 to 50 minutes, 10 to 40 minutes, or 10 to 30 minutes.
  • the water content of the crosslinked polymer at the end of the drying step may be 10% by mass or less, 8% by mass or less, 5% by mass or less, or less than 5% by mass.
  • the water content of the crosslinked polymer is defined as the ratio of the water content to the mass of the crosslinked polymer containing water.
  • the water content of the crosslinked polymer may be 0% by mass, may exceed 0% by mass, and may be 0.1% by mass or more or 0.5% by mass or more.
  • the water content of the crosslinked polymer can be measured by the method described in Examples described later.
  • At the end of the drying process is the time when all the drying treatments for the crosslinked polymer are completed, the time when the blowing of hot air to the crosslinked polymer is completed, the time when the crosslinked polymer is taken out from the dryer, and the like. It's okay. The same applies to the following.
  • the surface temperature T1 of the crosslinked polymer at the end of the drying step (all drying steps) is preferably in the following range.
  • the surface temperature T1 is preferably 250 ° C. or lower, 200 ° C. or lower, 190 ° C. or lower, 185 ° C. or lower, or 180 ° C. or lower from the viewpoint of easily obtaining crosslinked polymer particles having a small amount of fine powder.
  • the surface temperature T1 is 70 ° C. or higher, 80 ° C. or higher, 90 ° C. or higher, 100 ° C. or higher, 120 ° C. or higher, 140 ° C. or higher, 150 ° C. or higher, 160 ° C. or higher from the viewpoint of easily obtaining crosslinked polymer particles having a small amount of fine powder.
  • the surface temperature T1 is preferably 70 to 250 ° C. or 150 to 200 ° C.
  • the surface temperature T1 may be 175 ° C. or lower, 170 ° C. or lower, 165 ° C. or lower, or 160 ° C. or lower.
  • the surface temperature T1 can be measured using a radiation thermometer.
  • the method for producing crosslinked polymer particles according to this embodiment may include a plurality of drying steps.
  • the drying temperatures in the plurality of drying steps may be the same as each other or may be different from each other.
  • the drying means in the plurality of drying steps may be the same as each other or may be different from each other.
  • the method for producing the crosslinked polymer particles according to the present embodiment includes a first drying step for obtaining a crosslinked polymer having a water content of 30% by mass or less (for example, more than 10% by mass and 30% by mass or less), and a water content of 10% by mass.
  • a second drying step of obtaining a crosslinked polymer of% or less may be provided.
  • the method for producing crosslinked polymer particles according to the present embodiment may include a crushing step between a plurality of drying steps.
  • a crushing step between a plurality of drying steps.
  • the crushing step by performing the crushing step in a state where the water content is reduced by performing a drying treatment to some extent, it is possible to suppress excessive aggregation of the crosslinked polymer at the end of all the drying treatments, and the above-mentioned temperature can be suppressed. It is easy to confirm the effect of the difference ⁇ T.
  • the crosslinked polymer can be arranged to a certain size, the specific surface area can be increased and the crosslinked polymer can be dried, so that the variation in the water content among the particles of the crosslinked polymer can be reduced (can be uniformly dried). ..
  • As the crusher in the crushing step a roller mill, a hammer mill or the like can be used.
  • the method for producing crosslinked polymer particles according to the present embodiment may include a classification step for classifying the crosslinked polymer after the crushing step.
  • a classification step for classifying the crosslinked polymer after the crushing step.
  • particles having a particle diameter of 2.8 mm or more and less than 9.5 mm may be obtained.
  • crosslinked polymer particles may be obtained as a pulverized product.
  • the water content of the crosslinked polymer to be crushed in the crushing step may be in the above-mentioned range as the water content of the crosslinked polymer at the end of the drying step, and may be, for example, 10% by mass or less.
  • the particle size of the crosslinked polymer to be pulverized in the pulverization step is, for example, 20 mm or less, 15 mm or less, 10 mm or less, 9.5 mm or less, or less than 9.5 mm.
  • the crosslinked polymer can be crushed using a screen (mesh member, punching plate, etc.) having an opening (through hole; mesh).
  • a screen mesh member, punching plate, etc.
  • This embodiment may be, for example, an embodiment in which the crosslinked polymer is pulverized while passing the crosslinked polymer through the screen in the pulverization step.
  • the particles constituting the crosslinked polymer particles can be obtained on the other side of the screen.
  • the particle size can be adjusted while crushing the crosslinked polymer, and particles having a diameter corresponding to the opening diameter of the opening of the screen can be obtained on the other side of the screen.
  • the opening of the screen has an opening diameter larger than the diameter of at least a part of the crosslinked polymer to be ground.
  • the opening diameter (hole diameter) of the screen opening may be, for example, 0.08 to 10 mm, 0.50 to 2.0 mm, or 0.75 to 1.5 mm.
  • the screen may be annular (for example, annular), plate-shaped, or the like.
  • This embodiment may be, for example, an embodiment in which the crosslinked polymer is crushed while passing the crosslinked polymer through the screen by applying a centrifugal force to the crosslinked polymer in the crushing step.
  • the crosslinked polymer can be impact-ground by colliding the crosslinked polymer with a screen or another member (for example, a rotating member described later) by centrifugal force.
  • the screen is cyclic, and in the pulverization step, the crosslinked polymer is subjected to centrifugal force (centrifugal force from the inner peripheral side to the outer peripheral side) on the inner peripheral side of the screen.
  • centrifugal force centrifugal force from the inner peripheral side to the outer peripheral side
  • the particles constituting the crosslinked polymer particles can be obtained on the outer peripheral side of the screen. Further, the particle size can be adjusted while crushing the crosslinked polymer by impact crushing, and particles having a diameter corresponding to the opening diameter of the opening of the screen can be obtained on the outer peripheral side of the screen.
  • the crusher used in the crushing step may have, for example, a sample table to which the crosslinked polymer is supplied and an annular screen surrounding the sample table.
  • the sample table may be rotatable, and centrifugal force may be applied to the crosslinked polymer by rotating the sample table.
  • centrifugal force can be applied to the crosslinked polymer by rotating the sample table around the central axis (axis orthogonal to the circumferential direction) of the annular screen.
  • the crusher may include a rotating member (eg, a blade member) that can rotate along the inner wall of the annular screen.
  • a rotating member eg, a blade member
  • the crosslinked polymer is easily impact-crushed by colliding the crosslinked polymer with the rotating member by centrifugal force while rotating the rotating member.
  • the rotating member may be placed in the vicinity of the inner wall of the screen. In this case, it is possible to apply a shearing force to the crosslinked polymer existing between the rotating member and the inner wall of the screen, and the crosslinked polymer is easily crushed.
  • the rotating member may be a member extending along the central axis of the annular screen.
  • the rotating member may be integrated with the sample table or may be a separate body from the sample table.
  • the rotating member may be rotatable with the sample table.
  • a plurality (for example, 6) of rotating members may be arranged at intervals on the outer peripheral portion of the sample table.
  • the rotation speed of each of the sample table and the rotating member may be, for example, 6000 to 18000 rpm.
  • a product name manufactured by Retsch: ZM200; a product name manufactured by Fritsch Japan Co., Ltd .: P-14 rotor speed mill (Pulveristte 14) or the like can be used.
  • a crusher can be used in which the particles that have passed through the screen are not further adjusted in particle size.
  • a crusher other than a roll mill for example, a multi-stage roll mill
  • a single crusher may be used, or a plurality of types of crushers may be used.
  • the surface temperature T2 of the crosslinked polymer at the start of the pulverization step is preferably in the following range.
  • the surface temperature T2 is preferably 200 ° C. or lower, 180 ° C. or lower, 160 ° C. or lower, 150 ° C. or lower, 140 ° C. or lower, or 130 ° C. or lower from the viewpoint of easily obtaining crosslinked polymer particles having a small amount of fine powder.
  • the surface temperature T2 is 50 ° C. or higher, 55 ° C. or higher, 60 ° C. or higher, 80 ° C. or higher, 80 ° C. or higher, 90 ° C. or higher, 90 ° C. or higher, 100 ° C.
  • the surface temperature T2 is preferably 50 to 200 ° C., 100 to 160 ° C., or more than 100 ° C. and 160 ° C. or lower.
  • the surface temperature T2 may be 120 ° C. or lower, 110 ° C. or lower, 100 ° C. or lower, 90 ° C. or lower, 80 ° C. or lower, or 60 ° C. or lower.
  • the "starting time of the crushing step” may be a time when the crosslinked polymer is supplied to the crusher, a time when the crosslinked polymer is started to be supplied to the sample supply port of the crusher, and the like.
  • the surface temperature T2 can be measured using a radiation thermometer.
  • the temperature difference ⁇ T (T1-T2) between the surface temperature T1 of the crosslinked polymer at the end of the drying step and the surface temperature T2 of the crosslinked polymer at the start of the pulverization step is a viewpoint of obtaining crosslinked polymer particles having a small amount of fine powder. Therefore, it is more than 0 ° C and 100 ° C or less.
  • the surface temperature T1 is larger than the surface temperature T2 (T1> T2), and the temperature difference ⁇ T is a positive number.
  • the temperature difference ⁇ T is less than 100 ° C., 95 ° C. or lower, 90 ° C. or lower, less than 90 ° C., 85 ° C. or lower, 80 ° C. or lower, less than 80 ° C., 75 ° C. or lower from the viewpoint of easily obtaining crosslinked polymer particles having a small amount of fine powder.
  • 70 ° C or lower 70 ° C or less, 65 ° C or less, 60 ° C or less, 60 ° C or less, 55 ° C or less, 55 ° C or less, 50 ° C or less, less than 50 ° C, 45 ° C or less, 40 ° C or less, less than 40 ° C, 35 It is preferably °C or less, or 30 °C or less.
  • the temperature difference ⁇ T is preferably, for example, more than 0 ° C. and 90 ° C. or lower, or more than 0 ° C. and 85 ° C. or lower.
  • the temperature difference ⁇ T is 1 ° C or higher, 5 ° C or higher, 10 ° C or higher, 15 ° C or higher, 20 ° C or higher, 25 ° C or higher, 30 ° C or higher, 35 ° C or higher, 40 ° C or higher, 45 ° C or higher, 50 ° C or higher, 55. ° C. or higher, 60 ° C. or higher, 65 ° C. or higher, 70 ° C. or higher, 75 ° C. or higher, 80 ° C. or higher, 85 ° C. or higher, 90 ° C. or higher, or 95 ° C. or higher.
  • the time between the end of the drying step and the start of the pulverization step is 10 minutes or less, 5 minutes or less, 3 minutes or less, less than 3 minutes, 2.5 from the viewpoint that the elastic force of the crosslinked polymer does not easily decrease. Minutes or less, 2 minutes or less, 1.5 minutes or less, 1 minute or less, 0.5 minutes or less, or 0.33 (1/3) minutes or less is preferable.
  • the time between the end of the drying process and the start of the crushing process exceeds 0 minutes, 0.1 minutes or more, 0.2 minutes or more, 0.3 minutes or more, 0.33 (1/3) minutes. It may be 0.5 minutes or more, 1 minute or more, 1.5 minutes or more, 2 minutes or more, or 2.5 minutes or more.
  • the atmospheric temperature (the temperature of the atmosphere to which the crosslinked polymer is exposed) between the end of the drying step and the start of the crushing step may be in the following range.
  • the atmospheric temperature may be 150 ° C. or lower, 120 ° C. or lower, 100 ° C. or lower, 80 ° C. or lower, 50 ° C. or lower, 50 ° C. or lower, 40 ° C. or lower, 30 ° C. or lower, or 25 ° C. or lower.
  • the atmospheric temperature may be 10 ° C. or higher, 15 ° C. or higher, 20 ° C. or higher, or 25 ° C. or higher. From these viewpoints, the atmospheric temperature may be 10 to 150 ° C.
  • the crosslinked polymer may be left untreated without any treatment, or the crosslinked polymer may be treated.
  • the method for producing crosslinked polymer particles according to the present embodiment may include a coarse crushing step between the polymerization step and the drying step.
  • the coarse crushing step is, for example, a step of coarsely crushing the crosslinked polymer obtained in the polymerization step to obtain a coarsely crushed product.
  • the crusher in the crushing step for example, a kneader (pressurized kneader, double-armed kneader, etc.), a meat chopper, a cutter mill, a pharma mill, or the like can be used.
  • the coarse crushing step the hydrogel containing the crosslinked polymer may be coarsely crushed.
  • the crosslinked polymer for example, a water-containing gel of the crosslinked polymer
  • the gel may be subdivided.
  • the water content of the crosslinked polymer roughly crushed in the coarse crushing step exceeds, for example, 30% by mass.
  • the temperature difference between the surface temperature of the crosslinked polymer at the end of the drying step and the surface temperature of the crosslinked polymer at the start of the pulverization step is adjusted.
  • Crosslinked polymer particles having the following particle size distribution and / or medium particle size can be obtained.
  • the proportion of particles having a particle diameter of less than 180 ⁇ m (more than 0 ⁇ m and less than 180 ⁇ m) in the crosslinked polymer particles according to the present embodiment may be in the following range based on the total mass of the crosslinked polymer particles.
  • the proportion of particles having a particle diameter of less than 180 ⁇ m may be 22% by mass or less, 21% by mass or less, 20% by mass or less, 19% by mass or less, 18% by mass or less, 17% by mass or less, or 16% by mass or less. ..
  • the proportion of particles with a particle size of less than 180 ⁇ m is 0% by mass or more, more than 0% by mass, 1% by mass or more, 3% by mass or more, 5% by mass or more, 8% by mass or more, 10% by mass or more, 12% by mass or more. Alternatively, it may be 15% by mass or more. From these viewpoints, the proportion of particles having a particle diameter of less than 180 ⁇ m may be 0 to 22% by mass.
  • the proportion of particles having a particle diameter of less than 250 ⁇ m (more than 0 ⁇ m and less than 250 ⁇ m) in the crosslinked polymer particles according to the present embodiment may be in the following range based on the total mass of the crosslinked polymer particles.
  • the proportion of particles with a particle size of less than 250 ⁇ m is 34% by mass or less, 33% by mass or less, 32% by mass or less, 31% by mass or less, 30% by mass or less, 29% by mass or less, 28% by mass or less, 27% by mass or less. Alternatively, it may be 26% by mass or less.
  • the proportion of particles with a particle size of less than 250 ⁇ m is 0% by mass or more, more than 0% by mass, 1% by mass or more, 3% by mass or more, 5% by mass or more, 8% by mass or more, 10% by mass or more, 15% by mass or more. It may be 20% by mass or more, or 25% by mass or more. From these viewpoints, the proportion of particles having a particle diameter of less than 250 ⁇ m may be 0 to 34% by mass.
  • the proportion of particles having a particle diameter of 250 ⁇ m or more and less than 850 ⁇ m in the crosslinked polymer particles according to the present embodiment may be in the following range based on the total mass of the crosslinked polymer particles.
  • the proportion of particles with a particle size of 250 ⁇ m or more and less than 850 ⁇ m is 90% by mass or less, 85% by mass or less, 80% by mass or less, 75% by mass or less, 71% by mass or less, 70% by mass or less, 68% by mass or less, 67.5. It may be mass% or less, 67 mass% or less, or 66 mass% or less.
  • the proportion of particles with a particle size of 250 ⁇ m or more and less than 850 ⁇ m is 65% by mass or more, 66% by mass or more, 66.4% by mass or more, 67% by mass or more, 67.5% by mass or more, 68% by mass or more, 69% by mass or more. , Or 70% by mass or more. From these viewpoints, the proportion of particles having a particle diameter of 250 ⁇ m or more and less than 850 ⁇ m may be 65 to 90% by mass.
  • the proportion of particles having a particle diameter of 850 ⁇ m or more in the crosslinked polymer particles according to the present embodiment may be in the following range based on the total mass of the crosslinked polymer particles.
  • the proportion of particles having a particle diameter of 850 ⁇ m or more may be 10% by mass or less, less than 10% by mass, 8% by mass or less, 5% by mass or less, 4% by mass or less, or 3.6% by mass or less.
  • the proportion of particles with a particle size of 850 ⁇ m or more is 1% by mass or more, 1.2% by mass or more, 1.5% by mass or more, 1.8% by mass or more, 2% by mass or more, 2.5% by mass or more, and 3% by mass. % Or more, or 3.5% by mass or more. From these viewpoints, the proportion of particles having a particle diameter of 850 ⁇ m or more may be 1 to 10% by mass.
  • the mass ratio (fine particle abundance ratio) of the particles having a particle diameter of less than 250 ⁇ m to the particles having a particle diameter of 250 ⁇ m or more and less than 850 ⁇ m is 50% by mass or less and 48% by mass.
  • it is preferably 46.5% by mass or less, 45% by mass or less, 40% by mass or less, or 38% by mass or less.
  • the mass ratio can be measured by the method described in Examples described later.
  • the medium particle size of the crosslinked polymer particles according to this embodiment is preferably in the following range.
  • the medium particle size may be 200 ⁇ m or more, 230 ⁇ m or more, 250 ⁇ m or more, 280 ⁇ m or more, 300 ⁇ m or more, 330 ⁇ m or more, 350 ⁇ m or more, 360 ⁇ m or more, 370 ⁇ m or more, 380 ⁇ m or more, or 400 ⁇ m or more.
  • the medium particle size may be 600 ⁇ m or less, 550 ⁇ m or less, 500 ⁇ m or less, 450 ⁇ m or less, 400 ⁇ m or less, 390 ⁇ m or less, 380 ⁇ m or less, 370 ⁇ m or less, or 360 ⁇ m or less. From these viewpoints, the medium particle size may be 200 to 600 ⁇ m.
  • the medium particle size can be measured by the method described in Examples described later.
  • the crosslinked polymer particles according to the present embodiment may have a structural unit derived from an ethylenically unsaturated monomer (for example, a (meth) acrylic acid compound).
  • the crosslinked polymer particles according to the present embodiment include 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 acetic acid 5 sodium), etc.), and a fluidity improver (lubricant).
  • Other components such as may be further contained.
  • Other components may be located inside, on the surface, or both of the crosslinked polymers.
  • the crosslinked polymer particles according to the present embodiment may contain inorganic particles arranged on the surface of the crosslinked polymer.
  • the inorganic particles can be arranged on the surface of the crosslinked polymer.
  • the inorganic particles include silica particles such as amorphous silica.
  • the water-absorbent resin particles according to the present embodiment can be obtained by cross-linking the crosslinked polymer particles obtained in the pulverization step (crosslinking step).
  • the cross-linking may be surface cross-linking to the cross-linked polymer particles.
  • the cross-linking can be performed, for example, by reacting a cross-linking agent (for example, a surface cross-linking agent) with the cross-linked polymer particles.
  • a cross-linking agent for example, a surface cross-linking agent
  • the cross-linking density of the cross-linked polymer particles is increased, so that the water absorption performance can be easily improved.
  • cross-linking agent examples include compounds containing two or more functional groups (reactive functional groups) having reactivity with functional groups derived from ethylenically unsaturated monomers.
  • examples of the 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 diglycidyl ether, Polyglycidyl compounds such as (poly) glycerin diglycidyl ether, (poly) glycerin triglycidyl ether, (poly) propylene glycol polyglycidyl ether, (poly) glycerol polyglycidyl ether; Haloepoxy compounds; compounds having two or more reactive functional groups such as isocyanate compounds (2,4-tolylene diisocyanate, hexamethylene
  • the water-absorbent resin particles according to the present embodiment have a gel stabilizer on the surface thereof; a metal chelating agent (ethylenediamine 4 acetic acid and its salt, diethylenetriamine 5 acetic acid and its salt (for example, diethylenetriamine 5 acetic acid 5 sodium), etc.); It may contain inorganic particles of the agent (lubricant).
  • a metal chelating agent ethylenediamine 4 acetic acid and its salt, diethylenetriamine 5 acetic acid and its salt (for example, diethylenetriamine 5 acetic acid 5 sodium), etc.
  • the agent lubricant
  • the inorganic particles can be arranged on the surface of the particles after the cross-linking.
  • the inorganic particles include silica particles such as amorphous silica.
  • the water-absorbent resin particles according to the present embodiment can retain water and can absorb body fluids such as urine, sweat, and blood (for example, menstrual blood).
  • the water-absorbent resin particles according to this embodiment can be used as a constituent component of the absorber.
  • This embodiment can be used, for example, in the fields of sanitary materials such as disposable diapers and sanitary products; agricultural and horticultural materials such as water retention agents and soil conditioners; and industrial materials such as water blocking agents and dew condensation inhibitors.
  • the absorber according to the present embodiment contains the water-absorbent resin particles according to the present embodiment.
  • the absorber according to the present embodiment may contain a fibrous substance, and is, for example, a mixture containing water-absorbent resin particles and the fibrous substance.
  • the structure of the absorber may be, for example, a structure in which the water-absorbent resin particles and the fibrous material are uniformly mixed, and the water-absorbent resin particles are sandwiched between the fibrous material formed in the form of a sheet or a layer. It may be a configuration or another configuration.
  • the fibrous material examples include finely pulverized wood pulp; cotton; cotton linter; rayon; cellulosic fibers such as cellulose acetate; synthetic fibers such as polyamide, polyester and polyolefin; and a mixture of these fibers.
  • hydrophilic fibers can be used as the fibrous material.
  • the fibers may be adhered to each other by adding an adhesive binder to the fibrous material.
  • the adhesive binder include heat-sealing synthetic fibers, hot melt adhesives, adhesive emulsions and the like.
  • the heat-bondable synthetic fiber examples include a total fusion type binder such as polyethylene, polypropylene, and an ethylene-propylene copolymer; a side-by-side or non-total fusion type binder having a side-by-side or core-sheath structure of polypropylene and polyethylene.
  • a total fusion type binder such as polyethylene, polypropylene, and an ethylene-propylene copolymer
  • a side-by-side or non-total fusion type binder having a side-by-side or core-sheath structure of polypropylene and polyethylene.
  • hot melt adhesives examples include ethylene-vinyl acetate copolymer, styrene-isoprene-styrene block copolymer, styrene-butadiene-styrene block copolymer, styrene-ethylene-butylene-styrene block copolymer, and styrene-ethylene-propylene-styrene block copolymer.
  • a mixture of a base polymer such as amorphous styrene and a tackifier, a plasticizer, an antioxidant and the like.
  • Examples of the adhesive emulsion include polymers of at least one monomer selected from the group consisting of methyl methacrylate, styrene, acrylonitrile, 2-ethylhexyl acrylate, butyl acrylate, butadiene, ethylene, and vinyl acetate.
  • the absorber according to the present embodiment may contain inorganic particles (for example, amorphous silica), deodorant, antibacterial agent, pigment, dye, fragrance, adhesive and the like.
  • inorganic particles for example, amorphous silica
  • the absorber may contain the inorganic particles in addition to the inorganic particles in the water-absorbent resin particles.
  • the shape of the absorber according to the present embodiment may be, for example, a sheet.
  • the thickness of the absorber (for example, the thickness of the sheet-shaped absorber) may be 0.1 to 20 mm or 0.3 to 15 mm.
  • the content of the water-absorbent resin particles in the absorber is 2 to 95% by mass, 10 to 80% by mass, or 20 to 20 to 95% by mass with respect to the total of the water-absorbent resin particles and the fibrous material from the viewpoint of easily obtaining sufficient absorption characteristics. It may be 60% by mass.
  • the content of the water-absorbent resin particles in the absorber is preferably 100 to 1000 g, 150 to 800 g, or 200 to 700 g per 1 m 2 of the absorber from the viewpoint of easily obtaining sufficient absorption characteristics.
  • the content of the fibrous material in the absorber is preferably 50 to 800 g, 100 to 600 g, or 150 to 500 g per 1 m 2 of the absorber from the viewpoint of easily obtaining sufficient absorption characteristics.
  • the absorbent article according to the present embodiment includes an absorber according to the present embodiment.
  • a core wrap that retains the shape of the absorber and prevents the constituent member of the absorber from falling off or flowing; Liquid permeable sheet to be arranged; Examples thereof include a liquid permeable sheet arranged on the outermost side opposite to the side on which the liquid to be absorbed enters.
  • absorbent articles include diapers (for example, paper diapers), toilet training pants, incontinence pads, sanitary materials (sanitary napkins, tampons, etc.), sweat pads, pet sheets, simple toilet materials, animal excrement treatment materials, and the like. ..
  • the absorber may be adhered to the top sheet.
  • a hot melt adhesive is applied to the top sheet at predetermined intervals in a striped shape, a spiral shape, etc. in the width direction and bonded; starch, carboxymethyl cellulose, polyvinyl alcohol, polyvinylpyrrolidone, etc. Examples thereof include a method of adhering using a water-soluble binder such as a water-soluble polymer.
  • a method of adhering by heat-sealing of the heat-sealing synthetic fiber may be adopted.
  • the present embodiment it is possible to provide a liquid absorbing method using the water-absorbent resin particles, the absorbent body or the absorbent article according to the present embodiment.
  • the liquid absorbing method according to the present embodiment includes a step of bringing the liquid to be absorbed into contact with the water-absorbent resin particles, the absorber or the absorbent article according to the present embodiment.
  • the present embodiment it is possible to provide a method for producing an absorber using the above-mentioned water-absorbent resin particles.
  • the method for producing an absorber according to the present embodiment includes a process for producing water-absorbent resin particles for obtaining the above-mentioned water-absorbent resin particles.
  • the method for producing an absorber according to the present embodiment may include a step of mixing the water-absorbent resin particles and the fibrous material after the step of producing the water-absorbent resin particles.
  • the method for producing an absorbent article according to the present embodiment includes an absorbent body manufacturing step for obtaining an absorbent body by the above-mentioned method for manufacturing an absorbent body.
  • the method for producing an absorbent article according to the present embodiment may include, after the absorbent body manufacturing step, a step of obtaining the absorbent article by using the absorbent body and other constituent members of the absorbent article.
  • an absorbent article is obtained by laminating the absorber and other constituent members of the absorbent article with each other.
  • the present invention is not limited to the following examples. If the temperature at the time of the experimental operation is not described below, the experimental operation can be performed at room temperature.
  • ⁇ Preparation of crosslinked polymer> The concentration of a partial neutralizing solution of acrylic acid, 888.30 g, ion-exchanged water 144.39 g, and polyethylene glycol diacrylate (n ⁇ 9) 0.412 g (internal cross-linking agent, Nichiyu Co., Ltd., Blemmer ADE-400A). After placing 16.15 g of a 2 mass% potassium persulfate aqueous solution in a fluororesin-coated stainless steel bat (outer dimensions: 297 mm ⁇ 232 mm ⁇ height 50 mm), two stirrers (diameter 8 mm, length). Stirring with 45 mm (without ring) formed a uniform mixture in the stainless steel bat.
  • the upper part of the stainless steel vat was covered with a polyethylene film.
  • the amount of dissolved oxygen was adjusted to 0.1 ppm or less by substituting nitrogen in the mixture.
  • 3.39 g of a 0.5 mass% L-ascorbic acid aqueous solution was added dropwise using a syringe (Terumo Corporation, 10 mL disposable syringe, Terumo Corporation injection needle). ..
  • the entire amount of the hydrogel-like polymer after aging was taken out from the container, and the long sides were cut at intervals of 5 cm.
  • the cut hydrogel was sequentially put into a meat chopper (manufactured by Kiren Royal Co., Ltd., model number: 12VR-750SDX) and coarsely crushed (subdivided) at room temperature.
  • the diameter of the hole in the plate located at the outlet of the meat chopper was 6.4 mm.
  • hot air was used at 160 ° C. for 30 minutes using a hot air dryer (ADVANTEC, FV-320). It was dried to obtain a dried product.
  • the moisture content of the dried product was 5% by mass.
  • the dried product cooled to room temperature was classified with a JIS standard sieve having an opening of 9.5 mm and 2.8 mm, and the dried product remaining on the JIS standard sieve having an opening of 9.5 mm (particle size: 9.5 mm or more). ) was obtained.
  • the dried product was placed in a polyethylene bag, and a 4.0 kg roller (stainless steel, diameter: 10.5 cm, width: 6.0 cm) was reciprocated once on the bag to crush the dried product at room temperature. After that, it was classified again with a sieve having the same opening.
  • Example 1 After uniformly placing 40 g of the crosslinked polymer (A) in a fluororesin-coated stainless steel bat (outer dimensions: 208 mm ⁇ 170 mm ⁇ height 30 mm), a hot air dryer (ADVANTEC, FV-320) was used. The crosslinked polymer (A) was dried (heated) with hot air for 30 minutes at a drying temperature of 160 ° C. The surface temperature of the crosslinked polymer (A) (dried product) at the end of drying was 160 ° C., the water content was 3.9% by mass, and the particle size was 2.8 mm or more and less than 9.5 mm.
  • ADVANTEC hot air dryer
  • the surface temperature of the crosslinked polymer (A) (the surface temperature of the crosslinked polymer (A) when supplied to a centrifugal crusher) was measured. It was 130 ° C. The surface temperature was measured using a radiation thermometer (AD5611A, manufactured by A & D Co., Ltd.). Immediately thereafter, the crosslinked polymer (A) was supplied to a centrifugal crusher (Resch, ZM200, screen diameter: 1 mm, 6000 rpm), and the crosslinked polymer (A) was pulverized to form an amorphous crushed crosslinked weight. Combined particles were obtained.
  • Example 2 Crosslinked polymer particles were obtained by carrying out in the same manner as in Example 1 except that the drying temperature of the hot air dryer was changed to 180 ° C. and the leaving time at room temperature was changed to 30 seconds.
  • the surface temperature of the crosslinked polymer (A) at the end of drying was 180 ° C.
  • the surface temperature of the crosslinked polymer (A) when supplied to the centrifugal pulverizer was 150 ° C.
  • Example 3 Crosslinked polymer particles were obtained by carrying out in the same manner as in Example 1 except that the leaving time at room temperature was changed to 30 seconds.
  • the surface temperature of the crosslinked polymer (A) when supplied to the centrifugal pulverizer was 110 ° C.
  • Example 4 Crosslinked polymer particles were obtained by carrying out in the same manner as in Example 1 except that the drying temperature of the hot air dryer was changed to 180 ° C. and the leaving time at room temperature was changed to 1 minute.
  • the surface temperature of the crosslinked polymer (A) at the end of drying was 180 ° C., and the surface temperature of the crosslinked polymer (A) when supplied to the centrifugal pulverizer was 110 ° C.
  • Example 5 Crosslinked polymer particles were obtained by carrying out in the same manner as in Example 1 except that the leaving time at room temperature was changed to 1 minute.
  • the surface temperature of the crosslinked polymer (A) when supplied to the centrifugal pulverizer was 90 ° C.
  • Example 6 Crosslinked polymer particles were obtained by carrying out in the same manner as in Example 1 except that the leaving time at room temperature was changed to 2 minutes and 30 seconds.
  • the surface temperature of the crosslinked polymer (A) when supplied to the centrifugal pulverizer was 60 ° C.
  • ⁇ Particle size distribution and particle abundance ratio> Crosslinking weight after crushing with a sieve of 850 ⁇ m, 500 ⁇ m, 425 ⁇ m, 300 ⁇ m, 250 ⁇ m and 180 ⁇ m of JIS standard opening using a sieve shaker (PAT. No. 531413, manufactured by Iida Seisakusho Co., Ltd.) and a saucer.
  • the particle size distribution of 30 g of the coalesced particles was measured.
  • the total amount of the mass ratios of "more than 0 ⁇ m and less than 180 ⁇ m” and “180 ⁇ m or more and less than 250 ⁇ m” was calculated as the mass ratio of the particle size range of "less than 250 ⁇ m".
  • the mass ratio in the particle size range of "250 ⁇ m or more and less than 850 ⁇ m” is "250 ⁇ m or more and less than 300 ⁇ m", "300 ⁇ m or more and less than 425 ⁇ m", “425 ⁇ m or more and less than 500 ⁇ m", and "500 ⁇ m or more and less than 850 ⁇ m".
  • the total amount of proportions was calculated.

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Abstract

Le procédé de production de particules polymères réticulées selon la présente invention comprend une étape d'obtention d'un polymère réticulé par polymérisation d'un monomère, une étape de séchage pour sécher le polymère réticulé et une étape de pulvérisation pour pulvériser le polymère réticulé après séchage, la différence entre la température superficielle du polymère réticulé à la fin de l'étape de séchage et la température superficielle du polymère réticulé au début de l'étape de pulvérisation étant supérieure à 0 °C et inférieure ou égale à 100° C.
PCT/JP2021/019821 2020-06-04 2021-05-25 Procédé de production de particules polymères réticulées et procédé de production de particules de résine absorbant l'eau WO2021246243A1 (fr)

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Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2011190426A (ja) * 2010-02-19 2011-09-29 San-Dia Polymer Ltd 吸収性樹脂粒子及びこの製造方法
WO2015030130A1 (fr) * 2013-08-28 2015-03-05 株式会社日本触媒 Dispositif de pulvérisation de gel, procédé de fabrication de poudre de polymère superabsorbant de poly(acide acrylique) (polyacrylate) et poudre de polymère superabsorbant
WO2018135629A1 (fr) * 2017-01-23 2018-07-26 住友精化株式会社 Procédé de production d'une résine absorbant l'eau
JP2018119142A (ja) * 2017-01-23 2018-08-02 住友精化株式会社 架橋重合体の製造方法および吸水性樹脂の製造方法
WO2018174175A1 (fr) * 2017-03-24 2018-09-27 住友精化株式会社 Procédé de fabrication de résine absorbant l'eau
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

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2011190426A (ja) * 2010-02-19 2011-09-29 San-Dia Polymer Ltd 吸収性樹脂粒子及びこの製造方法
WO2015030130A1 (fr) * 2013-08-28 2015-03-05 株式会社日本触媒 Dispositif de pulvérisation de gel, procédé de fabrication de poudre de polymère superabsorbant de poly(acide acrylique) (polyacrylate) et poudre de polymère superabsorbant
WO2018135629A1 (fr) * 2017-01-23 2018-07-26 住友精化株式会社 Procédé de production d'une résine absorbant l'eau
JP2018119142A (ja) * 2017-01-23 2018-08-02 住友精化株式会社 架橋重合体の製造方法および吸水性樹脂の製造方法
WO2018174175A1 (fr) * 2017-03-24 2018-09-27 住友精化株式会社 Procédé de fabrication de résine absorbant l'eau
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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