WO2021006149A1 - 架橋重合体粒子の製造方法、及び、架橋重合体ゲル - Google Patents

架橋重合体粒子の製造方法、及び、架橋重合体ゲル Download PDF

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Publication number
WO2021006149A1
WO2021006149A1 PCT/JP2020/025844 JP2020025844W WO2021006149A1 WO 2021006149 A1 WO2021006149 A1 WO 2021006149A1 JP 2020025844 W JP2020025844 W JP 2020025844W WO 2021006149 A1 WO2021006149 A1 WO 2021006149A1
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Prior art keywords
crosslinked polymer
load
mmol
test piece
jig
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English (en)
French (fr)
Japanese (ja)
Inventor
河原　徹
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Sumitomo Seika Chemicals Co Ltd
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Sumitomo Seika Chemicals Co Ltd
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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
    • 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
    • A61F13/53—Absorbent pads, e.g. sanitary towels, swabs or tampons for external or internal application to the body; Supporting or fastening means therefor; Tampon applicators characterised by the absorbing medium
    • 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 crosslinked polymer gel.
  • an absorbent containing a water-absorbent resin has been used as an absorbent article for absorbing a liquid containing water as a main component (for example, urine) (see, for example, Patent Document 1 below).
  • the water-absorbent resin can be obtained, for example, by using crosslinked polymer particles obtained by polymerizing an ethylenically unsaturated monomer to obtain a crosslinked polymer gel and then coarsely crushing the crosslinked polymer gel. ..
  • the water-absorbent resin constituting the absorber is required to have an excellent water retention amount. Then, in order to obtain a water-absorbent resin having an excellent water retention amount, it is preferable to use crosslinked polymer particles having an excellent water retention amount.
  • One aspect of the present invention includes a step of coarsely crushing a crosslinked polymer gel having a structural unit derived from an ethylenically unsaturated monomer, and the cutting force obtained by the following procedures (1) to (6) is 110 N.
  • a method for producing crosslinked polymer particles having a value of more than 450 N and less than 450 N (1) Six rectangular parallelepiped test pieces of 2 cm ⁇ 13 cm ⁇ 1.3 cm are obtained from the crosslinked polymer gel. (2) Install the jig with the cutting blade of the jig having the cutting blade facing downward in the vertical direction. (3) Place the test piece on the lower side in the vertical direction with respect to the cutting blade with the 2 cm ⁇ 13 cm surface of the test piece facing upward in the vertical direction.
  • Another aspect of the present invention is a crosslinked polymer gel having a structural unit derived from an ethylenically unsaturated monomer, and the cutting force obtained by the following procedures (1) to (6) is 110 N or more and 450 N.
  • a crosslinked polymer gel that is less than.
  • (1) Six rectangular parallelepiped test pieces of 2 cm ⁇ 13 cm ⁇ 1.3 cm are obtained from the crosslinked polymer gel.
  • crosslinked polymer particles having an excellent water retention amount can be obtained.
  • One aspect of the present invention can provide a method for producing crosslinked polymer particles capable of obtaining crosslinked polymer particles having an excellent water retention amount.
  • another aspect of the present invention can provide a crosslinked polymer gel capable of obtaining crosslinked polymer particles having an excellent water retention amount.
  • 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.
  • Saline refers to a 0.9% by mass sodium chloride aqueous solution.
  • Content of (meth) acrylic acid compound and “total mass of (meth) acrylic acid compound” mean the total amount of acrylic acid, acrylic acid salt, methacrylic acid and methacrylic acid salt.
  • Ppm means mass ppm.
  • the method for producing crosslinked polymer particles according to the present embodiment includes a gel coarse crushing step of coarsely crushing a crosslinked polymer gel (crosslinked polymer hydrous gel) having a structural unit derived from an ethylenically unsaturated monomer.
  • the crosslinked polymer gel (crosslinked polymer hydrous gel) according to the present embodiment has a structural unit derived from an ethylenically unsaturated monomer.
  • the cutting force (force when the crosslinked polymer gel is cut) obtained by the following procedures (1) to (6) is 110 N or more and less than 450 N.
  • Six rectangular parallelepiped test pieces of 2 cm ⁇ 13 cm ⁇ 1.3 cm are obtained from the crosslinked polymer gel.
  • crosslinked polymer particles having an excellent water retention amount for example, holding a centrifuge of 60 g / g or more.
  • Crosslinked polymer particles having a capacity (CRC: Centrifuge Retention Capacity) can be obtained.
  • CRC Centrifuge Retention Capacity
  • the cause is not limited to the following contents. That is, when the cutting force of the crosslinked polymer gel before coarse crushing is within the above range, the degree of crosslinking and / or the molecular weight of the crosslinked polymer gel is suitable, so that an excellent water retention amount can be obtained.
  • the degree of cross-linking and / or the molecular weight of the cross-linked polymer particles is low, so that the cross-linked weight is such that an excellent amount of water retention can be obtained.
  • the coalesced particles are soft).
  • a kneader pressurized kneader, double-armed kneader, etc.
  • a meat chopper a cutter mill, a pharmacomill, or the like
  • the roughing can be performed, for example, by using a roughing device having a discharge port having a circular hole having a diameter of 6.4 mm and a density of 40 holes / 36.30 cm 2 .
  • the method for producing crosslinked polymer particles according to the present embodiment may include a polymerization step for obtaining a crosslinked polymer gel having a structural unit derived from an ethylenically unsaturated monomer before the gel coarse crushing step.
  • a crosslinked polymer gel can be obtained by polymerizing an ethylenically unsaturated monomer.
  • test piece In the step (1), six rectangular parallelepiped test pieces of 2 cm ⁇ 13 cm ⁇ 1.3 cm are obtained from the crosslinked polymer gel.
  • the test piece can be obtained by cutting out from a massive crosslinked polymer gel.
  • a solid gel having no visible voids can be used.
  • voids are likely to be formed in the region where the stirrer used in the polymerization step was present, so that a test piece can be obtained from the region where the void is not formed.
  • the water content (room temperature (25 ⁇ 1 ° C.)) of the test piece may be, for example, 45 to 65% by mass, 50 to 60% by mass, or 53 to 57% by mass.
  • the water content of the test piece is measured as follows.
  • step (2) the jig is installed with the cutting blade of the jig having the cutting blade (blade) facing downward in the vertical direction.
  • the jig is connected to a load detector and can transmit the load applied to the jig to the detector.
  • the cutting blade has, for example, a cutting edge portion and a plate-shaped supporting portion that supports the cutting edge portion.
  • the cutting edge portion may be formed on the entire side of the support portion.
  • the cutting blade (cutting edge and support) extends in one direction (long).
  • the length (length in the longitudinal direction) of the cutting blade (cutting edge portion and support portion) is 2 cm or more, which is the length of one side of the test piece.
  • the cutting edge portion is narrowed in the tip direction (direction from the support portion to the cutting edge portion; the traveling direction of the blade), and has a sharp tip.
  • the length of the cutting edge portion in the tip direction is, for example, 3 mm.
  • the length (width) of the base end and the support portion of the cutting edge portion in the directions orthogonal to the tip end direction and the longitudinal direction is, for example, 3 mm.
  • the cutting edge portion has a first blade surface that is inclined from one surface of the support portion to the tip direction, and a second blade surface that is inclined from the other surface of the support portion to the tip direction.
  • the first blade surface and the second blade surface are inclined by 22.5 ° with respect to the tip direction, and the angle (internal angle) between the first blade surface and the second blade surface is 45 °.
  • the shape of the cross section perpendicular to the longitudinal direction at the cutting edge is, for example, an isosceles triangle.
  • step (3) the test piece is installed on the lower side in the vertical direction with respect to the cutting blade with the 2 cm x 13 cm surface of the test piece facing upward in the vertical direction.
  • one surface of the test piece of 2 cm ⁇ 13 cm faces upward in the vertical direction, and the other surface of the test piece of 2 cm ⁇ 13 cm is in contact with the measuring table.
  • the test piece is installed in a state where the cutting blade (longitudinal direction of the cutting blade) is orthogonal to the longitudinal direction of the test piece (direction of the side having a length of 13 cm).
  • step (4) the cutting blade is pushed into the test piece in the vertical direction, and the load applied to the jig is measured.
  • the alignment may be performed by bringing the tip of the cutting blade into contact with the test piece.
  • the scanning speed of the cutting blade in step (4) is set to 20 mm / min.
  • step (4) the cutting blade is pushed into the test piece in the vertical direction, and the load displacement curve of the load with respect to the displacement of the jig (the load displacement curve showing the dependence of the load on the displacement of the jig. Horizontal axis: displacement of the jig. , Vertical axis: load applied to the jig) is acquired.
  • step (5) the load of the peak top (apex) of the peak observed at the time of cutting the test piece is acquired in the load displacement curve of the load with respect to the displacement of the jig for the six test pieces.
  • FIG. 1 is a diagram (load displacement curve) for explaining the test contents of the cutting test. The load tends to increase as the cutting blade is pushed into the test piece, and when the test piece is cut, the load rises sharply and then drops sharply, and a peak is observed (FIG. 1 (a)). See), get the load of the peak top P. If the test piece is not cut, the load continues to increase and no sharp drop in load is observed (see FIG. 1 (b)).
  • step (6) the average value of the peak top load in the six test pieces is acquired as the cutting force.
  • the cutting force is the force when the crosslinked polymer gel is cut, and is 110 N or more and less than 450 N from the viewpoint of obtaining an excellent water retention amount.
  • the cutting force tends to be sufficiently large in the dissolved components in the obtained crosslinked polymer particles, and from the viewpoint of easily reducing the irritation given to the user's skin when the absorber is used, 110N or more, 130N or more, 140N or more, 150N or more. , 170N or more, 200N or more, 220N or more, 240N or more, or 250N or more is preferable.
  • the cutting force may be 255 N or more, 260 N or more, 265 N or more, 270 N or more, or 275 N or more.
  • Cutting power is 440N or less, 430N or less, 420N or less, 410N or less, 400N or less, 380N or less, 360N or less, 340N or less, 320N or less, 300N or less, 280N or less, or 275N from the viewpoint of easily obtaining an excellent water retention amount.
  • the cutting force may be 270 N or less, 265 N or less, 260 N or less, or 255 N or less.
  • a cutting force at room temperature 25 ⁇ 1 ° C.
  • the cutting force can be measured by the method described in Examples described later.
  • the crosslinked polymer gel and the crosslinked polymer particles according to the present embodiment can contain a crosslinked polymer obtained by polymerizing an ethylenically unsaturated monomer, and simply contain an ethylenically unsaturated monomer.
  • a crosslinked polymer obtained by polymerizing a monomer composition can be included.
  • the crosslinked polymer gel and the crosslinked polymer particles according to the present embodiment are 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 sodium acetate), etc.), fluidity.
  • Other components such as an improver (lubricant) may be further contained.
  • Other components may be located inside, on the surface, or both of the crosslinked polymers. Examples of the shape of the crosslinked polymer particles include crushed and granular shapes.
  • the crosslinked polymer gel and the crosslinked polymer particles 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 monomer composition may contain water, an organic solvent, and the like.
  • the monomer composition may be a monomer aqueous solution.
  • the monomer polymerization method include an aqueous solution polymerization method, a bulk polymerization method, and a precipitation polymerization method.
  • the aqueous solution polymerization method is preferable from the viewpoint that good water absorption performance (water retention amount, etc.) can be easily obtained and the polymerization reaction can be easily controlled.
  • the aqueous solution polymerization method is used as an example of the polymerization method will be described.
  • the monomer composition contains an ethylenically unsaturated monomer.
  • a water-soluble ethylenically unsaturated monomer can be used.
  • 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; Nonionic monomers such as meta) acrylamide, N, N-dimethyl (meth) acrylamide, 2-hydroxyethyl (meth) acrylate, N-methylol (meth) acrylamide, polyethylene glycol mono (meth) acrylate; N, N -Amino group-containing unsaturated monomers such as diethylaminoethyl (meth) acrylate, N, N-diethylaminopropyl (meth) acrylate, diethylamino
  • Examples thereof include acids, 2- (meth) acrylamide-2-methylpropanesulfonic acid, 2- (meth) acryloylethanesulfonic acid, and sulfonic acid-based monomers such as salts thereof.
  • the salt for example, a salt of (meth) acrylic acid
  • examples of the salt include an alkali metal salt (sodium salt, potassium salt, etc.), an alkaline earth metal salt (calcium salt, etc.) and the like.
  • the ethylenically unsaturated monomer contains at least one (meth) acrylic acid compound selected from the group consisting of (meth) acrylic acid and salts thereof from the viewpoint of easily obtaining an excellent water retention capacity and being industrially available. Is preferable. That is, the crosslinked polymer particles preferably have a structural unit derived from an ethylenically unsaturated monomer containing a (meth) acrylic acid compound from the viewpoint of easily obtaining an excellent water retention amount.
  • the ethylenically unsaturated monomer having an acid group may have an acid group neutralized in advance with an alkaline neutralizer.
  • 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. Neutralization of the acid group may be carried out before the polymerization of the ethylenically unsaturated monomer as a raw material, or may be carried out during or after the polymerization.
  • the degree of neutralization of the ethylenically unsaturated monomer by the alkaline neutralizing agent is from the viewpoint that good water absorption performance (water retention amount, etc.) can be easily obtained by increasing the osmotic pressure, and the presence of excess alkaline neutralizing agent. From the viewpoint of suppressing defects caused by the above, 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 (meth) acrylic acid compound is preferably in the following range based on the total mass of the monomer composition.
  • the content of the (meth) acrylic acid compound is 10% by mass or more, 15% by mass or more, 20% by mass or more, 25% by mass or more, and 30% by mass from the viewpoint of low water content to be removed from the obtained gel and good drying efficiency. % Or more, or 35% by mass or more is preferable.
  • the content of the (meth) acrylic acid compound is 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 from the viewpoint of easily obtaining an excellent water retention amount. % Or less is preferable.
  • the content of the (meth) acrylic acid compound is preferably 10 to 60% by mass.
  • the content of the structural unit derived from the (meth) acrylic acid compound is the above-mentioned content regarding the content of the (meth) acrylic acid compound based on the total mass of the crosslinked polymer particles. It is preferably in each range.
  • 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 monomer 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). It may be.
  • the monomer composition may contain a chain transfer agent, if necessary.
  • the chain transfer agent include thiols, thiol acids, secondary alcohols, hypophosphorous acid, phosphorous acid, achlorine, benzaldehyde and the like, and benzaldehyde is preferable.
  • Benzaldehyde may be contained in the (meth) acrylic acid compound, and may constitute a monomer composition independently of the (meth) acrylic acid compound.
  • the monomer composition may not contain benzaldehyde, and the content of benzaldehyde is 0 ppm with respect to the total mass of the ethylenically unsaturated monomer or the total mass of the (meth) acrylic acid compound. It may be there.
  • the content of benzaldehyde exceeds 0 mmol with respect to 1 mol of the ethylenically unsaturated monomer or 1 mol of the (meth) acrylic acid compound, and is described below.
  • the range of is preferable.
  • the content of benzaldehyde is 0.0001 mmol or more, 0.0003 mmol or more, 0.0005 mmol or more, 0.001 mmol or more, 0.0025 mmol or more, 0.003 mmol from the viewpoint of easily obtaining an excellent water retention amount.
  • 0.003 mmol, 0.005 mmol or more, 0.01 mmol or more, 0.012 mmol or more, 0.02 mmol or more, 0.03 mmol or more, 0.05 mmol or more, or 0.06 Millimole or higher is preferred.
  • the content of benzaldehyde is 10 mmol or less, 7 mmol or less, 6 mmol or less, 5 mmol or less, from the viewpoint of easily obtaining an excellent water retention amount and suppressing the residual unreacted monomer.
  • the content of benzaldehyde is preferably more than 0 mmol and 10 mmol or less.
  • the content of benzaldehyde is 0.08 mmol or more, 0.1 mmol or more, more than 0.1 mmol, 0.2 mmol or more, 0.25 mmol or more, 0.3 mmol or more, and more than 0.3 mmol.
  • benzaldehyde may be 0.32 mmol or more.
  • the content of benzaldehyde may be 0.3 mmol or less, 0.25 mmol or less, 0.2 mmol or less, 0.15 mmol or less, 0.1 mmol or less, or 0.08 mmol or less.
  • the content of benzaldehyde exceeds 0 ppm based on the total mass of the monomer composition, and the following range is preferable.
  • the content of benzaldehyde is 0.02 ppm or more, 0.1 ppm or more, 0.15 ppm or more, 0.2 ppm or more, 0.5 ppm or more, 1.0 ppm or more, 1.5 ppm or more from the viewpoint of easily obtaining an excellent water retention amount.
  • 2.0ppm or more 5.0ppm or more, 7.5ppm or more, 10ppm or more, 12ppm or more, 12.5ppm or more, 20ppm or more, 25ppm or more, 30ppm or more, 35ppm or more, 50ppm or more, 60ppm or more, 62.5ppm or more, It is preferably 75 ppm or more, 80 ppm or more, 90 ppm or more, or 100 ppm or more.
  • the content of benzaldehyde is preferably 3000 ppm or less, 2000 ppm or less, 1500 ppm or less, 1000 ppm or less, 800 ppm or less, 600 ppm or less, or 500 ppm or less from the viewpoint of easily obtaining an excellent water retention amount. From these viewpoints, the content of benzaldehyde is preferably more than 0 ppm and 3000 ppm or less.
  • the content of benzaldehyde may be 125 ppm or more, 150 ppm or more, 175 ppm or more, 200 ppm or more, 250 ppm or more, 300 ppm or more, 350 ppm or more, 400 ppm or more, 450 ppm or more, or 500 ppm or more.
  • the content of benzaldehyde may be 450 ppm or less, 400 ppm or less, 350 ppm or less, 300 ppm or less, 250 ppm or less, 200 ppm or less, 175 ppm or less, 150 ppm or less, 125 ppm or less, or 100 ppm or less.
  • 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 and a radical polymerization initiator, 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 obtaining an excellent water retention amount.
  • azo compounds examples include 2,2'-azobis [2- (N-phenylamidino) propane] dihydrochloride and 2,2'-azobis ⁇ 2- [N- (4-chlorophenyl) amidino] propane ⁇ dihydrochloride.
  • Azo compounds are 2,2'-azobis (2-methylpropionamide) dihydrochloride and 2,2'-azobis (2-amidinopropane) from the viewpoint that good water absorption performance (water retention, etc.) can be easily obtained.
  • Peroxides include persulfates such as potassium persulfate, ammonium persulfate, and sodium persulfate; methyl ethyl ketone peroxide, methyl isobutyl ketone peroxide, di-t-butyl peroxide, t-butyl cumyl peroxide, t-butyl. Examples thereof include organic peroxides such as peroxyacetate, t-butylperoxyisobutyrate, and t-butylperoxypivalate.
  • the peroxide preferably contains at least one selected from the group consisting of potassium persulfate, ammonium persulfate, and sodium persulfate from the viewpoint that good water absorption performance (water retention amount, etc.) can be easily obtained.
  • the content of the polymerization initiator is preferably in the following range with respect to 1 mol of the ethylenically unsaturated monomer or 1 mol of the (meth) acrylic acid compound.
  • the content of the polymerization initiator is 0.001 mmol or more, 0.003 mmol or more, 0.015 mmol or more, 0.03 mmol from the viewpoint of easily obtaining an excellent water retention amount and shortening the polymerization reaction time.
  • 0.06 mmol or more, 0.08 mmol or more, or 0.1 mmol or more is preferable.
  • the content of the polymerization initiator is 5 mmol or less, 4 mmol or less, 2 mmol or less, 1 mmol or less, 0.5 mmol from the viewpoint of easily obtaining an excellent water retention amount and avoiding a rapid polymerization reaction.
  • it is preferably 0.3 mmol or less, 0.25 mmol or less, 0.2 mmol or less, or 0.15 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-linked polymer can have a cross-linked 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 an unsaturated acid (maleic acid, fumaric acid, etc.); (poly) ethylene glycol diglycidyl ether, (poly) propylene glycol diglycidyl ether, (poly) glycerin Glycidyl group-containing compounds such as diglycidyl ether and glycidyl (meth) acrylate; bisacrylamides such as N, N'-methylenebis (meth) acrylamide; di or tri (meth) obtained by reacting polyepoxide with (meth) acrylic acid.
  • unsaturated acid maleic acid, fumaric acid, etc.
  • Meta) acrylic acid esters di (meth) acrylic acid carbamil esters obtained by reacting polyisocyanates (tolylene diisocyanate, hexamethylene diisocyanate, etc.) with hydroxyethyl (meth) acrylic acid; allylated starch; allyl Cellified cellulose; diallyl phthalate; N, N', N "-triallyl isocyanurate; divinylbenzene; pentaerythritol; ethylenediamine; polyethyleneimine, etc.
  • polyisocyanates tolylene diisocyanate, hexamethylene diisocyanate, etc.
  • the internal cross-linking agent is easy to obtain an excellent water retention amount, and From the viewpoint of excellent reactivity at low temperature, it is preferable to contain at least one selected from the group consisting of (poly) ethylene glycol diglycidyl ether, (poly) propylene glycol diglycidyl ether, and (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 or 1 mol of the (meth) acrylic acid compound.
  • the content of the internal cross-linking agent is 0.0005 mmol or more, 0.001 mmol or more, 0.002 mmol or more, 0.005 mmol or more, 0. from the viewpoint that good water absorption performance (water retention amount, etc.) can be easily obtained. It is preferably 01 mmol or more, 0.015 mmol or more, 0.02 mmol or more, or 0.025 mmol or more.
  • the content of the internal cross-linking agent is 0.3 mmol or less, 0.25 mmol or less, 0.2 mmol or less, 0.18 mmol or less, 0. from the viewpoint that good water absorption performance (water retention amount, etc.) can be easily obtained. Less than 18 mmol, 0.17 mmol or less, 0.16 mmol or less, 0.15 mmol or less, 0.1 mmol or less, 0.06 mmol or less, less than 0.06 mmol, 0.05 mmol or less, 0.05 mmol Less than, 0.04 mmol or less, or 0.03 mmol or less is preferable. From these viewpoints, the content of the internal cross-linking agent is preferably 0.0005 to 0.3 mmol.
  • the monomer composition may contain additives such as thickeners and inorganic fillers as components different from the above-mentioned components.
  • the thickener include carboxymethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, methyl cellulose, polyethylene glycol, polyacrylic acid, neutralized polyacrylic acid, 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 is 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, removing the heat of polymerization, and facilitating 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 method for producing crosslinked polymer particles according to the present embodiment may include a drying step of drying the crude product (gel coarse crushed product) after the gel coarse crushing step.
  • a dried product (gel dried product) can be obtained by removing liquid components (water, etc.) in the pyroclastic material by heating and / or blowing air.
  • the drying method may be natural drying, heat drying, spray drying, freeze drying or the like.
  • the drying temperature is, for example, 70 to 250 ° C. Drying can be performed, for example, at 180 ° C. for 30 minutes.
  • the method for producing crosslinked polymer particles according to the present embodiment may include a dried product crushing step of crushing the dried product after the drying step.
  • Crushers include roller mills (roll mills), stamp mills, jet mills, high-speed rotary crushers (hammer mills, pin mills, rotor beater mills, etc.), container-driven mills (rotary mills, vibration mills, planetary mills, etc.). Can be mentioned.
  • the pulverization can be performed, for example, under the condition of a trapezoidal hole of 1 mm on the screen.
  • the method for producing crosslinked polymer particles according to the present embodiment may include a classification step of classifying the crushed product (crushed product of the dried product) after the dried product crushing step.
  • the classification step may be performed a plurality of times by repeating the dry matter crushing step and the classification step, and the classification step may be performed after the additional crosslinking step described later.
  • Examples of the classification method include screen classification and wind power classification. Examples of the screen classification include a vibrating sieve, a rotary shifter, a cylindrical stirring sieve, a blower shifter, and a low-tap type shaker.
  • 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 by vibrating the screen.
  • Wind classification is a method of classifying particles using the flow of air.
  • the particles obtained in the classification step may be particles having a particle size of 180 to 850 ⁇ m.
  • the water-absorbent resin according to the present embodiment can be obtained by cross-linking the polymer after the gel rough crushing step.
  • the cross-linking may be performed at any time after the gel coarse crushing step, and may be performed before or after the drying step, before or after the crushing step, or before or after the classification step.
  • the cross-linking may be a surface cross-linking to the 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 polymer.
  • the cross-linking density of the polymer (for example, the cross-linking density near the surface of the polymer particles) is increased, so that the water absorption performance of the polymer (CRC, water absorption under load, water absorption rate, etc.) ) Is easy to increase.
  • 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; epichlorohydrin, epibromhydrin, ⁇ -methylepicrolhydrin, etc.
  • Haloepoxy compounds compounds having two or more reactive functional groups, such as isocyanate compounds (2,4-tolylene diisocyanate, hexamethylenediisocyanate, etc.); 3-methyl-3-oxetane methanol, 3-ethyl-3-oxetane Oxetane compounds such as methanol, 3-butyl-3-oxetane methanol, 3-methyl-3-oxetane ethanol, 3-ethyl-3-oxetane ethanol, 3-butyl-3-oxetane ethanol; 1,2-ethylenebisoxazoline and the like.
  • the water-absorbent resin according to the present embodiment has a gel stabilizer on its surface; a metal chelating agent (ethylenediaminetetraacetic acid and a salt thereof, diethylenetriamine-5 acetic acid and a salt thereof (for example, diethylenetriamine-5 sodium acetate), etc.); a fluidity improver.
  • a metal chelating agent ethylenediaminetetraacetic acid and a salt thereof, diethylenetriamine-5 acetic acid and a salt thereof (for example, diethylenetriamine-5 sodium acetate), etc.
  • a fluidity improver may contain inorganic particles of (lubricant) and the like.
  • the inorganic particles include silica particles such as amorphous silica.
  • the water-absorbent resin 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 according to the present embodiment can be used as a constituent component of the absorber.
  • This embodiment can be used in the fields of, for example, 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 stop agents and dew condensation inhibitors.
  • the absorber according to the present embodiment contains the water-absorbent resin (for example, water-absorbent resin particles) according to the present embodiment.
  • the absorber according to the present embodiment may contain a fibrous substance, for example, a mixture containing a water-absorbent resin and the fibrous substance.
  • the structure of the absorber may be, for example, a structure in which the water-absorbent resin and the fibrous material are uniformly mixed, and the water-absorbent resin is sandwiched between the fibrous material formed in a sheet or layer. It may be present or may have other configurations.
  • 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, and adhesive emulsions.
  • the heat-bondable synthetic fiber examples include a total fusion type binder such as polyethylene, polypropylene, and an ethylene-propylene copolymer; a 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
  • non-total fusion type binder having a side-by-side or core-sheath structure of polypropylene and polyethylene.
  • hot melt adhesive 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 polypropylene 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 an inorganic powder (for example, amorphous silica), a deodorant, an antibacterial agent, a pigment, a dye, a fragrance, an adhesive and the like.
  • an inorganic powder for example, amorphous silica
  • the absorber may contain an inorganic powder in addition to the inorganic particles in the water-absorbent resin.
  • the shape of the absorber according to the present embodiment may be, for example, a sheet shape.
  • 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 in the absorber is 2 to 95% by mass, 10 to 80% by mass, or 20 to 60% by mass with respect to the total of the water-absorbent resin and the fibrous material from the viewpoint of easily obtaining sufficient absorption characteristics. May be%.
  • the content of the water-absorbent resin 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; on the outermost side on the side where the liquid to be absorbed enters.
  • Liquid permeable sheet to be arranged Examples thereof include a liquid permeable sheet arranged on the outermost side opposite to the side where 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. ..
  • FIG. 2 is a cross-sectional view showing an example of an absorbent article.
  • the absorbent article 100 shown in FIG. 2 includes an absorbent body 10, core wraps 20a and 20b, a liquid permeable sheet 30, and a liquid permeable sheet 40.
  • the liquid permeable sheet 40, the core wrap 20b, the absorbent body 10, the core wrap 20a, and the liquid permeable sheet 30 are laminated in this order.
  • FIG. 2 there is a portion shown so that there is a gap between the members, but the members may be in close contact with each other without the gap.
  • the absorber 10 has water-absorbent resin particles 10a containing the water-absorbent resin according to the present embodiment, and a fiber layer 10b containing a fibrous material.
  • the water-absorbent resin particles 10a are dispersed in the fiber layer 10b.
  • the core wrap 20a is arranged on one side of the absorber 10 (upper side of the absorber 10 in FIG. 2) in contact with the absorber 10.
  • the core wrap 20b is arranged on the other side of the absorber 10 (lower side of the absorber 10 in FIG. 2) in contact with the absorber 10.
  • the absorber 10 is arranged between the core wrap 20a and the core wrap 20b.
  • Examples of the core wraps 20a and 20b include tissues, non-woven fabrics, woven fabrics, synthetic resin films having liquid permeation holes, net-like sheets having a mesh, and the like.
  • the core wrap 20a and the core wrap 20b have, for example, a main surface having the same size as the absorber 10.
  • the liquid permeable sheet 30 is arranged on the outermost side on the side where the liquid to be absorbed enters.
  • the liquid permeable sheet 30 is arranged on the core wrap 20a in contact with the core wrap 20a.
  • Examples of the liquid permeable sheet 30 include non-woven fabrics made of synthetic resins such as polyethylene, polypropylene, polyester and polyamide, and porous sheets.
  • the liquid permeable sheet 40 is arranged on the outermost side of the absorbent article 100 on the opposite side of the liquid permeable sheet 30.
  • the liquid permeable sheet 40 is arranged under the core wrap 20b in contact with the core wrap 20b.
  • liquid impermeable sheet 40 examples include a sheet made of a synthetic resin such as polyethylene, polypropylene, and polyvinyl chloride, and a sheet made of a composite material of these synthetic resins and a non-woven fabric.
  • the liquid permeable sheet 30 and the liquid permeable sheet 40 have, for example, a main surface wider than the main surface of the absorber 10, and the outer edges of the liquid permeable sheet 30 and the liquid permeable sheet 40 are It extends around the absorber 10 and the core wraps 20a, 20b.
  • the magnitude relationship between the absorbent body 10, the core wraps 20a and 20b, the liquid permeable sheet 30, and the liquid permeable sheet 40 is not particularly limited, and is appropriately adjusted according to the use of the absorbent article and the like. Further, the method of retaining the shape of the absorber 10 by using the core wraps 20a and 20b is not particularly limited, and as shown in FIG. 2, the absorber may be wrapped by a plurality of core wraps, and the absorber is wrapped by one core wrap. It may be.
  • 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 adhered; starch, carboxymethyl cellulose, polyvinyl alcohol, polyvinyl pyrrolidone, 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 fibers may be adopted.
  • the liquid absorbing method according to the present embodiment includes a step of bringing the liquid to be absorbed into contact with the water absorbing resin, 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.
  • the method for producing an absorber according to the present embodiment includes a water-absorbent resin manufacturing step for obtaining the above-mentioned water-absorbent resin.
  • the method for producing an absorber according to the present embodiment may include a step of mixing the water-absorbent resin and the fibrous material after the process of producing the water-absorbent resin.
  • the method for producing an absorbent article according to the present embodiment includes an absorber manufacturing step for obtaining an absorber by the above-mentioned method for manufacturing an absorber.
  • the method for producing an absorbent article according to the present embodiment may include a step of obtaining an absorbent article by using the absorber and other constituent members of the absorbent article after the absorbent body manufacturing step. For example, an absorbent article is obtained by laminating the absorber and other constituent members of the absorbent article with each other.
  • the present embodiment it is possible to provide an application of a water-absorbent resin, an absorber and an absorbent article to a liquid-absorbing liquid.
  • a method for adjusting the water retention amount of the crosslinked polymer particles which is a method for adjusting the water retention amount using the crosslinked polymer gel according to the present embodiment (for example, an improving method).
  • the method for adjusting the amount of water retained according to the present embodiment includes an adjusting step for adjusting the cutting force obtained by the above-mentioned procedures (1) to (6) for the crosslinked polymer gel according to the present embodiment. In the adjusting step, the cutting force can be adjusted to each of the above ranges (for example, 110 N or more and less than 450 N).
  • the crosslinked polymer gel according to the present embodiment includes a selection step of selecting crosslinked polymer particles based on the cutting force obtained by the above-mentioned procedures (1) to (6).
  • a method for producing particles can be provided.
  • the cutting force can be adjusted to each of the above ranges (for example, 110 N or more and less than 450 N).
  • Partial neutralizing solution of sodium acrylate (monomer used for polymerization, monomer concentration: 45% by mass, neutralization rate of sodium acrylate: 75 mol%) 340.0 g, ethylene glycol diglycidyl ether 0.0541 g (inside)
  • the cross-linking agent 0.11 mmol
  • benzaldehyde 1.245 mg 0.117 mmol
  • 59.0 g of ion-exchanged water the mixture was uniformly mixed by rotating the stirrer to mix (sodium acrylate). Partial neutralizing solution concentration: 38% by mass) was obtained.
  • the inside of the stainless steel vat was sealed by sealing the upper part of the stainless steel vat with a polyethylene film.
  • the obtained product was immersed in a water bath at 75 ° C. for 20 minutes while still in a container to obtain a gel (post-polymerization gel).
  • the thickness of the gel was 1.3 cm.
  • the same operation was repeated to obtain two gels, a gel A for performing a cutting test and a gel B for producing crosslinked polymer particles.
  • Example 2 A gel was obtained by performing the same operation as in Example 1 except that the amount of benzaldehyde used was changed to 12.45 mg (0.117 mmol).
  • Partial neutralizing solution of sodium acrylate (monomer used for polymerization, monomer concentration: 45% by mass, neutralization rate of sodium acrylate: 75 mol%) 340.0 g, ethylene glycol diglycidyl ether 0.0077 g (inside)
  • the cross-linking agent 0.044 mmol
  • 37.35 mg (0.352 mmol) of benzaldehyde, and 59.0 g of ion-exchanged water the mixture was uniformly mixed by rotating the stirrer to mix (sodium acrylate). Partial neutralizing solution concentration: 38% by mass) was obtained.
  • the inside of the stainless steel vat was sealed by sealing the upper part of the stainless steel vat with a polyethylene film.
  • the amount of dissolved oxygen was adjusted to 0.1 ppm or less by substituting nitrogen in the mixture. Then, under stirring at 300 rpm, 3.48 g (2,2'-azobis (2-amidinopropane) dihydrochloride, 0.257 mmol, manufactured by Wako Pure Chemical Industries, Ltd.), 0, 2 mass% V-50 aqueous solution.
  • a monomer aqueous solution was prepared by sequentially dropping 0.73 g of a 5.5 mass% L-ascorbic acid aqueous solution and 0.81 g of a 0.35 mass% hydrogen peroxide solution. Polymerization started immediately after the 0.35 mass% hydrogen peroxide solution was added dropwise.
  • the obtained product was immersed in a water bath at 75 ° C. for 20 minutes while still in a container to obtain a gel (post-polymerization gel).
  • the thickness of the gel was 1.3 cm.
  • the same operation was repeated to obtain two gels, a gel A for performing a cutting test and a gel B for producing crosslinked polymer particles.
  • Example 5 A gel was obtained by performing the same operation as in Example 4 except that the amount of benzaldehyde used was changed to 37.35 mg (0.352 mmol).
  • Example 6 A gel was obtained by performing the same operation as in Example 4 except that the amount of benzaldehyde used was changed to 62.26 mg (0.587 mmol).
  • Example 7 A gel was obtained by performing the same operation as in Example 4 except that the amount of benzaldehyde used was changed to 124.5 mg (1.173 mmol).
  • Example 8 The same operation as in Example 4 was carried out except that the amount of ethylene glycol diglycidyl ether used was changed to 0.0155 g (0.089 mmol) and the amount of benzaldehyde used was changed to 1.245 mg (0.0117 mmol). Gel was obtained by doing.
  • Example 2 The same operation as in Example 4 was carried out except that the amount of ethylene glycol diglycidyl ether used was changed to 0.0541 g (0.311 mmol) and the amount of benzaldehyde used was changed to 1.245 mg (0.0117 mmol). Gel was obtained by doing.
  • Example 3 The same operation as in Example 4 was carried out except that the amount of ethylene glycol diglycidyl ether used was changed to 0.0541 g (0.311 mmol) and the amount of benzaldehyde used was changed to 124.5 mg (1.173 mmol). Gel was obtained by doing.
  • a cutting test was conducted using EZtest (product name: EZtest, model number: EZ-SX, manufactured by Shimadzu Corporation).
  • the blade used to cut the gel (long cutting blade, catalog name: 45 ° cut end face t3 mm) has a capacity of 500 N (measurement upper limit is set to 450 N) with the tip of the blade facing downward in the vertical direction.
  • the jig was assembled by attaching it to the load cell of.
  • the blade has a cutting edge portion (length in the tip direction: 3 mm, a cutting edge portion narrowed toward the tip direction and having a sharp tip) and a plate-shaped support portion that supports the cutting edge portion. ing.
  • the length of the cutting blade including the cutting edge portion in the longitudinal direction is 7 cm.
  • the cutting edge portion is formed on the entire side of the supporting portion, and the width of the base end of the cutting edge portion and the supporting portion is 3 mm.
  • the cutting edge portion has a first blade surface that is inclined from one surface of the support portion to the tip direction, and a second blade surface that is inclined from the other surface of the support portion to the tip direction.
  • the first blade surface and the second blade surface are inclined by 22.5 ° with respect to the tip direction, and the angle (internal angle) between the first blade surface and the second blade surface is 45 °. ..
  • the shape of the cross section perpendicular to the longitudinal direction at the cutting edge is an isosceles triangle.
  • test piece was cut according to the following procedure by operating the blade attached to the EZtest using the Shimadzu autograph software Trapezium X (manufactured by Shimadzu Corporation). Cutting was performed at room temperature (25 ⁇ 1 ° C.).
  • the test piece was placed on the measuring table in a state where the 2 cm ⁇ 13 cm surface of the test piece was in contact with the measuring table and the longitudinal direction of the test piece was orthogonal to the longitudinal direction of the blade.
  • the blade was manually lowered and stopped when the load cell sensed a load of 0.01 N. After that, the blade was raised by 0.01 mm and its position was set as the measurement start point.
  • the blade is pushed into the surface of the test piece at a speed of 20 mm / min from the measurement start point (set to move automatically by the programming function of Trapezium X), and the load applied to the jig when the gel is cut. was measured.
  • the load increases as the blade is pushed into the gel, and when the gel is cut, the load rises sharply and then drops sharply to observe a peak (see FIG. 1A), and the peak top P The load of was obtained. If the test piece was not cut, the load reached the measurement upper limit of 450 N (see FIG. 1 (b)).
  • the pyroclastic material was spread on a net and then dried in a hot air dryer (model number: FV-320, manufactured by ADVANTEC) set at 180 ° C. for 30 minutes to obtain a dried product.
  • a crusher (Retsch, Rotavita Mill, SR300) was used to crush the dried product under the condition of a trapezoidal hole of 1 mm on the screen.
  • a non-woven fabric with a size of 60 mm x 170 mm (product name: Heat Pack MWA-18, manufactured by Nippon Paper Papylia Co., Ltd.) was folded in half in the longitudinal direction to adjust the size to 60 mm x 85 mm.
  • a 60 mm ⁇ 85 mm non-woven fabric bag was produced by crimping the non-woven fabrics to each other on both sides extending in the longitudinal direction with a heat seal (a crimped portion having a width of 5 mm was formed on both sides along the longitudinal direction).
  • 0.2 g of the above-mentioned crosslinked polymer particles was contained in the non-woven fabric bag. Then, the non-woven fabric bag was closed by crimping the remaining one side extending in the lateral direction with a heat seal.
  • the entire non-woven fabric bag was completely moistened by floating the non-woven fabric bag on 1000 g of physiological saline contained in a stainless steel vat (240 mm ⁇ 320 mm ⁇ 45 mm) without folding the non-woven fabric bag.
  • a stainless steel vat 240 mm ⁇ 320 mm ⁇ 45 mm
  • the non-woven fabric bag was taken out from the physiological saline solution. Then, the non-woven fabric bag was put in a centrifuge (manufactured by Kokusan Co., Ltd., model number: H-122). After the centrifugal force in the centrifuge reached 250 G, the non-woven fabric bag was dehydrated for 3 minutes. After dehydration, it was weighed mass M a nonwoven bag containing the mass of gel. Subjected to the same operation as the aforementioned operation on the woven bags without accommodating the crosslinked polymer particles, the mass was measured M b of the nonwoven fabric bag.
  • 10 Absorbent, 10a ... Water-absorbent resin particles, 10b ... Fiber layer, 20a, 20b ... Core wrap, 30 ... Liquid permeable sheet, 40 ... Liquid permeable sheet, 100 ... Absorbent article.

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EP3995515A4 (en) * 2019-07-05 2023-07-05 Sumitomo Seika Chemicals Co., Ltd. CROSSLINKED POLYMER GEL, METHOD FOR PRODUCING IT, MONOMER COMPOSITION, AND METHOD FOR PRODUCING CROSSLINKED POLYMER PARTICLES

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JP2005154741A (ja) * 2003-10-27 2005-06-16 Mitsubishi Chemicals Corp レドックス重合法
JP2007501315A (ja) * 2003-08-06 2007-01-25 ザ プロクター アンド ギャンブル カンパニー コーティングされた水膨潤性材料
JP2009173942A (ja) * 1998-03-11 2009-08-06 Nippon Shokubai Co Ltd 親水性樹脂、吸収物品および重合用アクリル酸
JP2010235692A (ja) * 2009-03-30 2010-10-21 Sanyo Chem Ind Ltd ペットシート用吸水性樹脂及びそれを用いたペットシート
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JP2009173942A (ja) * 1998-03-11 2009-08-06 Nippon Shokubai Co Ltd 親水性樹脂、吸収物品および重合用アクリル酸
JP2002020406A (ja) * 2000-07-10 2002-01-23 Idemitsu Petrochem Co Ltd 不飽和カルボン酸重合体架橋化物とその製造法
JP2007501315A (ja) * 2003-08-06 2007-01-25 ザ プロクター アンド ギャンブル カンパニー コーティングされた水膨潤性材料
JP2005154741A (ja) * 2003-10-27 2005-06-16 Mitsubishi Chemicals Corp レドックス重合法
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Publication number Priority date Publication date Assignee Title
EP3995515A4 (en) * 2019-07-05 2023-07-05 Sumitomo Seika Chemicals Co., Ltd. CROSSLINKED POLYMER GEL, METHOD FOR PRODUCING IT, MONOMER COMPOSITION, AND METHOD FOR PRODUCING CROSSLINKED POLYMER PARTICLES

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