WO2021049450A1 - Particules de résine absorbant l'eau - Google Patents

Particules de résine absorbant l'eau Download PDF

Info

Publication number
WO2021049450A1
WO2021049450A1 PCT/JP2020/033753 JP2020033753W WO2021049450A1 WO 2021049450 A1 WO2021049450 A1 WO 2021049450A1 JP 2020033753 W JP2020033753 W JP 2020033753W WO 2021049450 A1 WO2021049450 A1 WO 2021049450A1
Authority
WO
WIPO (PCT)
Prior art keywords
water
absorbent resin
resin particles
gel
amount
Prior art date
Application number
PCT/JP2020/033753
Other languages
English (en)
Japanese (ja)
Inventor
萌 西田
Original Assignee
住友精化株式会社
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 住友精化株式会社 filed Critical 住友精化株式会社
Priority to JP2021545518A priority Critical patent/JPWO2021049450A1/ja
Publication of WO2021049450A1 publication Critical patent/WO2021049450A1/fr

Links

Images

Classifications

    • 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
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J20/00—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof
    • B01J20/22—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof comprising organic material
    • B01J20/26—Synthetic macromolecular compounds
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J20/00—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof
    • B01J20/28—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof characterised by their form or physical properties
    • 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
    • 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
    • C08J3/24—Crosslinking, e.g. vulcanising, of macromolecules

Definitions

  • the present invention relates to water-absorbent resin particles.
  • Water-absorbent resin particles are used in the field of hygiene products, and are used as a material for absorbent bodies contained in absorbent articles such as diapers.
  • Patent Documents 1 and 2 below disclose water-absorbent resin particles having a predetermined water absorption rate based on the Vortex method at 600 rpm.
  • the absorber is required to permeate the liquid at an excellent permeation rate.
  • An object of the present invention is to provide absorbent resin particles that provide an absorber having an excellent permeation rate.
  • One aspect of the present invention is that the amount of water retained in the physiological saline is 15 to 50 g / g, the amount of water absorbed in the physiological saline under a load of 4.14 kPa is 13 mL / g or more, and the following (1), Water-absorbent resin particles having a gel diffusion aspect ratio of 2.6 or less measured by a method including the steps (2), (3), (4), (5), (6) and (7) in this order. Regarding. (1) A swelling gel is obtained by adding 10 g of water-absorbent resin particles to 290 g of physiological saline stirred at 600 rpm and allowing the water-absorbent resin particles to absorb water for 2 minutes.
  • a transparent container having an inner dimension of 20 cm in width, 16 cm in height and 1.5 cm in thickness and having an opening at the top is horizontally installed, and 200 g of the swelling gel is evenly charged into the container.
  • a lid having a piston portion having a width of 19.8 cm, a height of 10 cm, and a width of 1.3 cm and a mass of 0.45 kg is placed horizontally on the swollen gel in the container, and a weight of 1.35 kg is further placed on the lid. Place on the lid for 30 seconds and remove the lid from the container.
  • the remaining 100 g of swelling gel is added to the container, and the step (3) is repeated to form a swelling gel layer.
  • a burette is placed at a position 3 cm above the center of the upper surface of the swollen gel layer, and 10 ml of blue physiological saline is added to the swollen gel layer at 2 ml / sec. (6) The steps (5) are performed three more times at 10-minute intervals. (7) Five minutes after the start of the fourth injection of blue physiological saline, the maximum length of the stained area observed from the side surface of the container in the horizontal direction and the maximum length in the vertical direction were measured, and the maximum length in the horizontal direction was measured. The gel diffusion aspect ratio is determined by dividing the length by the maximum length in the vertical direction.
  • the gel outflow ratio is preferably 30% or less.
  • the present invention also provides an absorber containing the above water-absorbent resin particles.
  • the present invention also provides an absorbent article comprising the absorber.
  • the absorbent article may be a diaper.
  • the water-absorbent resin particles include the following steps (1), (2), (3), (4), (5), (6) and (7) in this order.
  • the present invention relates to a method for measuring a gel diffusion aspect ratio.
  • a swelling gel is obtained by adding 10 g of water-absorbent resin particles to 290 g of physiological saline stirred at 600 rpm and allowing the water-absorbent resin particles to absorb water for 2 minutes.
  • a transparent container having an inner dimension of 20 cm in width, 16 cm in height and 1.5 cm in thickness and having an opening at the top is horizontally installed, and 200 g of the swelling gel is evenly charged into the container.
  • a lid having a piston portion having a width of 19.8 cm, a height of 10 cm, and a width of 1.3 cm and a mass of 0.45 kg is placed horizontally on the swollen gel in the container, and a weight of 1.35 kg is further placed on the lid. Place on the lid for 30 seconds and remove the lid from the container.
  • the remaining 100 g of swelling gel is added to the container, and the step (3) is repeated to form a swelling gel layer.
  • a burette is placed at a position 3 cm above the center of the upper surface of the swollen gel layer, and 10 ml of blue physiological saline is added to the swollen gel layer at 2 ml / sec.
  • the steps (5) are performed three more times at 10-minute intervals.
  • Yet another aspect of the present invention is that the amount of water retained in the saline is 15 to 50 g / g, the amount of water absorbed in the saline under a load of 4.14 kPa is 13 mL / g or more, and the above method.
  • the present invention relates to a method for producing water-absorbent resin particles, which comprises selecting water-absorbent resin particles having a gel diffusion aspect ratio of 2.6 or less as measured by.
  • Yet another aspect of the present invention is to measure the water retention amount of the physiological saline solution to 15 to 50 g / g, the water absorption amount to the physiological saline solution under a load of 4.14 kPa to 13 mL / g or more, and the above method.
  • the present invention relates to a method for improving the permeation rate of an absorber containing the water-absorbent resin particles, which comprises adjusting the gel diffusion aspect ratio to 2.6 or less.
  • 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.
  • the water-absorbent resin particles according to the present embodiment have a water retention amount of 15 to 50 g / g for physiological saline, a water absorption amount for physiological saline under a load of 4.14 kPa of 13 mL / g or more, and the following.
  • the gel diffusion aspect ratio measured by the method is 2.6 or less.
  • FIG. 1 is a schematic view showing a gel diffusion aspect ratio measuring instrument
  • FIG. 2 is a schematic view showing an example of gel diffusion aspect ratio measurement.
  • the gel diffusion aspect ratio of the water-absorbent resin particles is measured by a method including the following steps (1), (2), (3), (4), (5), (6) and (7) in this order. ..
  • a swelling gel is obtained by adding 10 g of water-absorbent resin particles to 290 g of physiological saline stirred at 600 rpm and allowing the water-absorbent resin particles to absorb water for 2 minutes.
  • a transparent container 51 having an inner dimension of 20 cm in width, 16 cm in height and 1.5 cm in thickness and having an opening at the top is horizontally installed, and 200 g of swelling gel is evenly charged into the transparent container 51.
  • a lid 52 having a mass of 0.45 kg and having a piston portion 53 having a width of 19.8 cm, a height of 10 cm and a width of 1.3 cm is horizontally placed on the swollen gel in the transparent container 51, and further 1.35 kg.
  • the weight is placed on the lid for 30 seconds, and the lid 52 is removed from the transparent container 51.
  • the remaining 100 g of the swelling gel is added into the transparent container 51, and the step (3) is repeated to form the swelling gel layer 54.
  • the shape of the obtained swollen gel layer 54 can be adjusted and the reproducibility of the measurement can be improved.
  • a burette 55 is placed at a position 3 cm above the center of the upper surface of the swollen gel layer 54, and 10 ml of blue physiological saline is poured into the swollen gel layer 54 at 2 ml / sec.
  • the steps (5) are repeated 3 times at 10-minute intervals, for a total of 4 times.
  • the tip shape of the burette into which the blue saline solution is added is not horizontal with respect to the burette axis direction but is inclined, for example, the longest part of the burette tip is on the side surface having a width of 20 cm. Place it so that it faces you. The boundary between the stained area 56 and the unstained area can be visually confirmed.
  • the surface for measuring the maximum length in the vertical direction and the horizontal direction in the dyed area 56 is the side surface having the longer maximum length in the vertical direction of the dyed area 56 among the two sides having a width of 20 cm.
  • gel blocking is a phenomenon in which water-absorbing water-absorbent resin particles swell to form a gel, and the swelling gels condense to block the passage of liquid, and as a result, hinder the passage or absorption of further liquid.
  • the permeation rate as an absorber tends to decrease.
  • the maximum length in the vertical direction in the dyed region 56 of the swollen gel layer becomes longer in the above method for measuring the gel diffusion aspect ratio.
  • the present inventors do not necessarily have a high penetration rate in the absorber even if the absolute value of the maximum length in the vertical direction in the stained region 56 is long, and surprisingly, the maximum horizontal length in the stained region 56 of the swollen gel layer. We found that the balance between length and maximum length in the vertical direction is important.
  • the gel diffusion aspect ratio of the water-absorbent resin particles according to this embodiment may be 2.5 or less.
  • the gel diffusion aspect ratio may be, for example, 1.5 or more, 1.7 or more, or 2.0 or more.
  • the maximum length in the vertical direction of the stained area 56 measured by the above method may be, for example, 5 cm or more or 6 cm or more, and may be 15 cm or less, 12 cm or less, or 10 cm or less.
  • the maximum horizontal length of the stained area 56 measured by the above method may be, for example, 10 cm or more, 12 cm or more or 14 cm or more, and may be 20 cm or less, 19 cm or less or 18 cm or less.
  • the amount of water-absorbent resin particles according to the present embodiment with respect to physiological saline is 15 to 50 g / g. When the amount of water retained is within these ranges, the permeation rate of the absorber tends to increase.
  • the water retention amount of the water-absorbent resin particles with respect to the physiological saline may be 18 to 50 g / g, 18 to 45 g / g, or 25 to 43 g / g.
  • the amount of water-absorbent resin particles retained in physiological saline is measured by the method described in Examples described later.
  • the water-absorbent resin particles according to the present embodiment have a water absorption amount of the water-absorbent resin particles with respect to physiological saline under a load of 4.14 kPa (hereinafter, may be referred to as "water absorption amount under load”) of 13 mL / g or more. Is.
  • water absorption amount under load When the water absorption amount of the water-absorbent resin particles under load is 13 mL / g, the permeation rate of the absorber tends to be high. As a result, the permeation rate of the physiological saline solution into the absorber after the load is applied in the state of absorbing water can be further increased.
  • a large amount of water absorption under load is also advantageous in that gel blocking is unlikely to occur in an absorbent article.
  • the amount of water absorption of the water-absorbent resin particles under load may be 15 mL / g or more, 18 mL / g or more, or 20 mL / g or more, 35 mL / g or less, 30 mL / g or less, 28 mL / g or less, or 26 mL / g. It may be less than or equal to g.
  • the amount of water absorption under load is measured by the method described in Examples described later.
  • FIG. 4 and FIG. 5 are schematic views showing a method of measuring the gel outflow ratio of the water-absorbent resin particles.
  • the methods shown in FIGS. 3 to 5 include the following steps (1), (2), (3), (4), (5), (6) and (7) in this order.
  • the gel outflow ratio is measured in an environment of 25 ⁇ 2 ° C.
  • the tubular body 41 having the bottom portion 41B is fixed so that the longitudinal direction of the tubular body 41 is vertical and the bottom portion 41B is on the lower side (FIG. 3).
  • a disc 42 having a diameter of 4.9 cm and a thickness of 3.0 mm having a through hole H formed in the center on the bottom 41B is placed in a direction in which the main surface of the disc 42 is horizontal. Arrange (Fig. 3).
  • the through hole H has a wall surface inclined with respect to the main surface of the disc 42 so that the through hole H is the narrowest at the central position in the thickness direction of the disc 42.
  • (3) 20 g of the swelling gel 45 formed by the water-absorbent resin particles absorbing the physiological saline is placed in the tubular body 41 and placed on the disc 42.
  • the swollen gel 45 has a mass 30 times that of the mass of the water-absorbent resin particles before absorbing the physiological saline.
  • the tubular body 41 may be a molded body of an acrylic resin.
  • the tubular body 41 is fixed by using a fixing device such as a clamp.
  • Each weight is gently placed on the swelling gel 45 so that a momentary strong impact due to dropping is not applied to the swelling gel 45.
  • the entire amount of the swollen gel 45 that flowed out from the through hole H was collected, and its mass W (g) was measured. Will be done.
  • the swelling gel 45 that has flowed out often falls, but when a part or all of the swelling gel 45 that has flowed out is held in a state of hanging from the through hole H, it is below the main surface on the lower side of the disk 42.
  • the mass W of the swelling gel 45 that has flowed out is measured, including the swelling gel that hangs down at the position.
  • a small gel outflow ratio means that the swollen gel formed by the water-absorbent resin particles absorbing a large amount of physiological saline is difficult to move under a load.
  • the absorber absorbs the liquid, a swelling gel is formed inside. If the movement of the swelling gel is small when a load is applied to it, the swelling gel in the part where the load is applied remains stationary, so it can be absorbed even if physiological saline is added again. Therefore, it is considered that the permeation rate remains high.
  • the swelling gel in the portion to which the load is applied moves outward from the loaded portion, so that even if physiological saline is added again, the loaded portion It is considered that the amount that can be absorbed is limited and the permeation rate is slowed down.
  • the gel outflow ratio of the water-absorbent resin particles may be 27% or less or 25% or less. When the swelling gel 45 does not flow out from the through hole H at all, the gel outflow ratio is 0%, which is the lower limit of the gel outflow ratio.
  • the gel outflow ratio of the water-absorbent resin particles may be, for example, 2% or more or 5% or more.
  • Examples of the shape of the water-absorbent resin particles according to the present embodiment include a substantially spherical shape, a crushed shape, a granular shape, and a shape formed by aggregating primary particles having these shapes.
  • the medium particle size of the water-absorbent resin particles according to the present embodiment may be 130 to 800 ⁇ m, 200 to 850 ⁇ m, 250 to 700 ⁇ m, 300 to 600 ⁇ m, or 300 to 450 ⁇ m.
  • the water-absorbent resin particles according to the present embodiment may have a desired particle size distribution at the time of being obtained by the production method described later, but the particle size distribution can be obtained by performing an operation such as particle size adjustment using classification with a sieve. May be adjusted.
  • the water-absorbent resin particles according to the present embodiment can include, for example, a crosslinked polymer obtained by polymerizing a monomer containing an ethylenically unsaturated monomer as polymer particles. That is, the water-absorbent resin particles according to the present embodiment can have a structural unit derived from an ethylenically unsaturated monomer. As the ethylenically unsaturated monomer, a water-soluble ethylenically unsaturated monomer can be used. Examples of the polymerization method include a reverse phase suspension polymerization method, an aqueous solution polymerization method, a bulk polymerization method, and a precipitation polymerization method.
  • the reverse phase suspension polymerization method or the aqueous solution polymerization method is preferable from the viewpoint of ensuring good water absorption characteristics of the obtained water-absorbent resin particles and facilitating control of the polymerization reaction.
  • a reverse phase suspension polymerization method will be described as an example.
  • the ethylenically unsaturated monomer is preferably water-soluble, for example, (meth) acrylic acid and a salt thereof, 2- (meth) acrylamide-2-methylpropanesulfonic acid and a salt thereof, (meth) acrylamide, N. , N-dimethyl (meth) acrylamide, 2-hydroxyethyl (meth) acrylate, N-methylol (meth) acrylamide, polyethylene glycol mono (meth) acrylate, N, N-diethylaminoethyl (meth) acrylate, N, N-diethylamino Examples thereof include propyl (meth) acrylate and diethylaminopropyl (meth) acrylamide.
  • the amino group may be quaternized.
  • the ethylenically unsaturated monomer may be used alone or in combination of two or more.
  • the functional groups such as the carboxyl group and the amino group of the above-mentioned monomer can function as functional groups capable of cross-linking in the surface cross-linking step described later.
  • the ethylenically unsaturated monomer is a group consisting of (meth) acrylic acid and salts thereof, acrylamide, methacrylamide, and N, N-dimethylacrylamide. It is preferable to contain at least one compound selected from the above, and it is more preferable to contain at least one compound selected from the group consisting of (meth) acrylic acid and salts thereof, and acrylamide. From the viewpoint of further enhancing the water absorption property, the ethylenically unsaturated monomer further preferably contains at least one compound selected from the group consisting of (meth) acrylic acid and salts thereof. That is, the water-absorbent resin particles preferably have a structural unit derived from at least one selected from the group consisting of (meth) acrylic acid and salts thereof.
  • a monomer other than the above-mentioned ethylenically unsaturated monomer may be used.
  • Such a monomer can be used, for example, by mixing with an aqueous solution containing the above-mentioned ethylenically unsaturated monomer.
  • the amount of the ethylenically unsaturated monomer used is the total amount of the monomer (the total amount of the monomer for obtaining the water-absorbent resin particles. For example, the total amount of the monomer giving the structural unit of the crosslinked polymer. The same shall apply hereinafter).
  • the ratio of (meth) acrylic acid and its salt may be 70 to 100 mol% with respect to the total amount of the monomer, 80 to 100 mol%, 90 to 100 mol%, 95 to 100 mol%, or It may be 100 mol%.
  • Ratio of (meth) acrylic acid and its salt means the ratio of the total amount of (meth) acrylic acid and its salt.
  • the water-absorbent resin particles containing a crosslinked polymer having a structural unit derived from the ethylenically unsaturated monomer, wherein the ethylenically unsaturated monomer is used.
  • At least one compound selected from the group consisting of (meth) acrylic acid and salts thereof, and the ratio of (meth) acrylic acid and salts thereof is based on the total amount of monomers for obtaining water-absorbent resin particles. It is possible to provide water-absorbent resin particles in an amount of 70 to 100 mol%.
  • the ethylenically unsaturated monomer is usually preferably used as an aqueous solution.
  • concentration of the ethylenically unsaturated monomer in the aqueous solution containing the ethylenically unsaturated monomer (hereinafter, simply referred to as "monomeric aqueous solution”) is preferably 20% by mass or more and preferably 25 to 70% by mass. More preferably, 30 to 55% by mass is further preferable.
  • Examples of the water used in the aqueous solution include tap water, distilled water, ion-exchanged water and the like.
  • the aqueous monomer solution may be used by neutralizing the acid group with an alkaline neutralizer.
  • the degree of neutralization of the ethylenically unsaturated monomer by the alkaline neutralizing agent increases the osmotic pressure of the obtained water-absorbent resin particles and further enhances the water-absorbing characteristics. It is preferably 10 to 100 mol%, more preferably 50 to 90 mol%, and even more preferably 60 to 80 mol% of the group.
  • the alkaline neutralizing agent include alkali metal salts such as sodium hydroxide, sodium carbonate, sodium hydrogen carbonate, potassium hydroxide and potassium carbonate; ammonia and the like.
  • the alkaline neutralizer may be used alone or in combination of two or more.
  • the alkaline neutralizer may be used in the form of an aqueous solution to simplify the neutralization operation.
  • the acid group of the ethylenically unsaturated monomer can be neutralized by, for example, adding an aqueous solution of sodium hydroxide, potassium hydroxide or the like to the above-mentioned aqueous monomer solution and mixing them.
  • an aqueous monomer solution is dispersed in a hydrocarbon dispersion medium in the presence of a surfactant, and an ethylenically unsaturated monomer is polymerized using a radical polymerization initiator or the like. Can be done.
  • Nonionic surfactants include sorbitan fatty acid ester, polyglycerin fatty acid ester, sucrose fatty acid ester, polyoxyethylene sorbitan fatty acid ester, polyoxyethylene glycerin fatty acid ester, sorbitol fatty acid ester, polyoxyethylene sorbitol fatty acid ester, and polyoxyethylene.
  • Alkyl ether polyoxyethylene alkyl phenyl ether, polyoxyethylene castor oil, polyoxyethylene hydrogenated castor oil, alkylallyl formaldehyde condensed polyoxyethylene ether, polyoxyethylene polyoxypropylene block copolymer, polyoxyethylene polyoxypropyl alkyl ether, Examples thereof include polyethylene glycol fatty acid ester.
  • Anionic surfactants include fatty acid salts, alkylbenzene sulfonates, alkylmethyl taurates, polyoxyethylene alkylphenyl ether sulfates, polyoxyethylene alkyl ether sulfonates, and polyoxyethylene alkyl ether phosphates. , Phosphate ester of polyoxyethylene alkyl allyl ether and the like.
  • the surfactant may be used alone or in combination of two or more.
  • the surfactant is a sorbitan fatty acid ester. It preferably contains at least one compound selected from the group consisting of polyglycerin fatty acid esters and sucrose fatty acid esters. From the viewpoint that an appropriate particle size distribution of the water-absorbent resin particles can be easily obtained, and from the viewpoint that the water-absorbing characteristics of the water-absorbent resin particles and the performance of the absorber and the absorbent article using the same can be easily improved, the surfactant is used as a detergent. It preferably contains a sugar fatty acid ester, more preferably a sucrose stearic acid ester.
  • the amount of the surfactant used is preferably 0.05 to 10 parts by mass with respect to 100 parts by mass of the aqueous monomer solution from the viewpoint of obtaining a sufficient effect on the amount used and economically. .08 to 5 parts by mass is more preferable, and 0.1 to 3 parts by mass is further preferable.
  • a polymer-based dispersant may be used in combination with the above-mentioned surfactant.
  • the polymer dispersant include maleic anhydride-modified polyethylene, maleic anhydride-modified polypropylene, maleic anhydride-modified ethylene / propylene copolymer, maleic anhydride-modified EPDM (ethylene / propylene / diene / terpolymer), and maleic anhydride.
  • the polymer-based dispersant may be used alone or in combination of two or more.
  • maleic anhydride-modified polyethylene maleic anhydride-modified polypropylene
  • maleic anhydride-modified ethylene / propylene copolymer maleic anhydride / ethylene copolymer weight.
  • maleic anhydride / propylene copolymer, maleic anhydride / ethylene / propylene copolymer, polyethylene, polypropylene, ethylene / propylene copolymer, oxidized polyethylene, oxidized polypropylene, and oxidized ethylene / propylene copolymer At least one selected from the group consisting of is preferable.
  • the amount of the polymer-based dispersant used is preferably 0.05 to 10 parts by mass with respect to 100 parts by mass of the aqueous monomer solution from the viewpoint of obtaining a sufficient effect on the amount used and economically. 0.08 to 5 parts by mass is more preferable, and 0.1 to 3 parts by mass is further preferable.
  • the hydrocarbon dispersion medium may contain at least one compound selected from the group consisting of chain aliphatic hydrocarbons having 6 to 8 carbon atoms and alicyclic hydrocarbons having 6 to 8 carbon atoms.
  • Hydrocarbon dispersion media include chain aliphatic hydrocarbons such as n-hexane, n-heptane, 2-methylhexane, 3-methylhexane, 2,3-dimethylpentane, 3-ethylpentane, and n-octane; cyclohexane.
  • the hydrocarbon dispersion medium may be used alone or in combination of two or more.
  • the hydrocarbon dispersion medium may contain at least one selected from the group consisting of n-heptane and cyclohexane from the viewpoint of being industrially easily available and having stable quality. From the same viewpoint, as the mixture of the above-mentioned hydrocarbon dispersion medium, for example, commercially available ExxonHeptane (manufactured by ExxonMobil: containing 75 to 85% of n-heptane and isomeric hydrocarbons) is used. You may.
  • the amount of the hydrocarbon dispersion medium used is preferably 30 to 1000 parts by mass and 40 to 500 parts by mass with respect to 100 parts by mass of the monomer aqueous solution from the viewpoint of appropriately removing the heat of polymerization and easily controlling the polymerization temperature. Is more preferable, and 50 to 400 parts by mass is further preferable.
  • the amount of the hydrocarbon dispersion medium used is 30 parts by mass or more, the polymerization temperature tends to be easily controlled.
  • the amount of the hydrocarbon dispersion medium used is 1000 parts by mass or less, the productivity of polymerization tends to be improved, which is economical.
  • the radical polymerization initiator is preferably water-soluble, for example, persulfates such as potassium persulfate, ammonium persulfate, sodium persulfate; methyl ethyl ketone peroxide, methyl isobutyl ketone peroxide, di-t-butyl peroxide, t.
  • persulfates such as potassium persulfate, ammonium persulfate, sodium persulfate
  • methyl ethyl ketone peroxide methyl isobutyl ketone peroxide, di-t-butyl peroxide, t.
  • -Peroxides such as butyl cumylperoxide, t-butylperoxyacetate, t-butylperoxyisobutyrate, t-butylperoxypivalate, hydrogen peroxide; 2,2'-azobis (2-amidinopropane) ) 2 hydrochloride, 2,2'-azobis [2- (N-phenylamidino) propane] 2 hydrochloride, 2,2'-azobis [2- (N-allylamidino) propane] 2 hydrochloride, 2,2 '-Azobis [2- (2-imidazolin-2-yl) propane] dihydrochloride, 2,2'-azobis ⁇ 2- [1- (2-hydroxyethyl) -2-imidazolin-2-yl] propane ⁇ Dihydrochloride, 2,2'-azobis ⁇ 2-methyl-N- [1,1-bis (hydroxymethyl) -2-hydroxyethyl] propionamide ⁇ , 2,2'-azobis [2-methyl-N-
  • the radical polymerization initiator may be used alone or in combination of two or more.
  • examples of the radical polymerization initiator include potassium persulfate, ammonium persulfate, sodium persulfate, 2,2'-azobis (2-amidinopropane) dihydrochloride, and 2,2'-azobis [2- (2-imidazolin-2-). At least one selected from the group consisting of i) propanate] 2 hydrochloride and 2,2'-azobis ⁇ 2- [1- (2-hydroxyethyl) -2-imidazolin-2-yl] propan ⁇ 2 hydrochloride preferable.
  • the amount of the radical polymerization initiator used may be 0.05 to 10 mmol per 1 mol of the ethylenically unsaturated monomer.
  • the amount of the radical polymerization initiator used is 0.05 mmol or more, the polymerization reaction does not require a long time and is efficient.
  • the amount of the radical polymerization initiator used is 10 mmol or less, it is easy to suppress the occurrence of a rapid polymerization reaction.
  • the above-mentioned radical polymerization initiator can also be used as a redox polymerization initiator in combination with a reducing agent such as sodium sulfite, sodium hydrogen sulfite, ferrous sulfate, and L-ascorbic acid.
  • a reducing agent such as sodium sulfite, sodium hydrogen sulfite, ferrous sulfate, and L-ascorbic acid.
  • the aqueous monomer solution used for the polymerization may contain a chain transfer agent.
  • the chain transfer agent include hypophosphates, thiols, thiolic acids, secondary alcohols, amines and the like.
  • the monomer aqueous solution used for the polymerization may contain a thickener in order to control the particle size of the water-absorbent resin particles.
  • the thickener include hydroxyethyl cellulose, hydroxypropyl cellulose, methyl cellulose, carboxymethyl cellulose, polyethylene glycol, polyacrylamide, polyethyleneimine, dextrin, sodium alginate, polyvinyl alcohol, polyvinylpyrrolidone, polyethylene oxide and the like. If the stirring speed at the time of polymerization is the same, the higher the viscosity of the aqueous monomer solution, the larger the medium particle size of the obtained particles tends to be.
  • Internal cross-linking may occur due to self-cross-linking during polymerization, but cross-linking may be performed by using an internal cross-linking agent.
  • an internal cross-linking agent When an internal cross-linking agent is used, it is easy to control the water absorption characteristics of the water-absorbent resin particles.
  • the internal cross-linking agent is usually added to the reaction solution during the polymerization reaction.
  • the internal cross-linking agent examples include di or tri (meth) acrylic acid esters of polyols such as ethylene glycol, propylene glycol, trimethylpropane, glycerin, polyoxyethylene glycol, polyoxypropylene glycol, and polyglycerin; Unsaturated polyesters obtained by reacting polyols with unsaturated acids (maleic acid, fumaric acid, etc.); bis (meth) acrylamides such as N, N'-methylenebis (meth) acrylamide; polyepoxides and (meth) Di or tri (meth) acrylic acid esters obtained by reacting with acrylic acid; di (meth) obtained by reacting polyisocyanate (tolylene diisocyanate, hexamethylene diisocyanate, etc.) with hydroxyethyl (meth) acrylate.
  • polyols such as ethylene glycol, propylene glycol, trimethylpropane, glycerin, polyoxyethylene glycol, polyoxypropy
  • Acrylic acid carbamil esters compounds having two or more polymerizable unsaturated groups such as allylated starch, allylated cellulose, diallyl phthalate, N, N', N "-triallyl isocyanurate, divinylbenzene; Polys such as (poly) ethylene glycol diglycidyl ether, (poly) propylene glycol diglycidyl ether, (poly) glycerin diglycidyl ether, (poly) glycerin triglycidyl ether, (poly) propylene glycol diglycidyl ether, polyglycerol polyglycidyl ether, etc.
  • Polys such as (poly) ethylene glycol diglycidyl ether, (poly) propylene glycol diglycidyl ether, (poly) glycerin diglycidyl ether, (poly) glycerin triglycidyl ether, (poly) propy
  • Glycidyl compounds such as epichlorohydrin, epibromhydrin, ⁇ -methylepichlorohydrin; 2 reactive functional groups such as isocyanate compounds (2,4-tolylene diisocyanate, hexamethylene diisocyanate, etc.) Examples thereof include compounds having more than one.
  • the internal cross-linking agent may be used alone or in combination of two or more. As the internal cross-linking agent, a polyglycidyl compound is preferable, and a diglycidyl ether compound is used.
  • the amount of the internal cross-linking agent used is from the viewpoint that an excellent permeation rate can be easily obtained in an absorbent article, and the water-soluble property is suppressed by appropriately cross-linking the obtained polymer, so that a sufficient water absorption amount can be obtained.
  • 30 mmol or less is preferable, 0.01 to 10 mmol is more preferable, 0.012 to 5 mmol is further preferable, and 0.015 to 1 mmol is particularly preferable, per 1 mol of the ethylenically unsaturated monomer.
  • 0.02 to 0.1 mmol is very preferred, and 0.025 to 0.08 mmol is very preferred.
  • a monomer aqueous solution containing an ethylenically unsaturated monomer is used as a hydrocarbon dispersion medium in the presence of a surfactant (more polymer-based dispersant if necessary). Disperse.
  • a surfactant more polymer-based dispersant if necessary.
  • the timing of adding the surfactant, the polymer-based dispersant, etc. may be either before or after the addition of the aqueous monomer solution, as long as it is before the start of the polymerization reaction.
  • the surface activity is applied after the monomer aqueous solution is dispersed in the hydrocarbon dispersion medium in which the polymer-based dispersant is dispersed. It is preferable to further disperse the agent before carrying out the polymerization.
  • Reverse phase suspension polymerization can be carried out in one stage or in multiple stages of two or more stages. Reversed phase suspension polymerization is preferably carried out in 2 to 3 steps from the viewpoint of increasing productivity.
  • an ethylenically unsaturated single amount is added to the reaction mixture obtained in the first-step polymerization reaction after the first-step reverse-phase suspension polymerization is carried out.
  • the bodies may be added and mixed, and the reverse phase suspension polymerization of the second and subsequent steps may be carried out in the same manner as in the first step.
  • the above-mentioned radical polymerization initiator and / or internal cross-linking agent is used in the reverse phase of each stage of the second and subsequent stages.
  • reverse-phase suspension polymerization is carried out by adding within the range of the molar ratio of each component to the above-mentioned ethylenically unsaturated monomer.
  • An internal cross-linking agent may be used in the reverse phase suspension polymerization in each of the second and subsequent stages, if necessary.
  • an internal cross-linking agent it is added within the range of the molar ratio of each component to the above-mentioned ethylenically unsaturated monomer based on the amount of the ethylenically unsaturated monomer provided in each stage, and the suspension is reversed.
  • the amount (molar amount) of the ethylenically unsaturated monomer used in the second stage is 0.5 to 1.8 times the amount (molar amount) of the ethylenically unsaturated monomer used in the first stage. Is preferable, and 0.8 to 1.6 times is more preferable.
  • the temperature of the polymerization reaction varies depending on the radical polymerization initiator used, but by rapidly advancing the polymerization and shortening the polymerization time, the efficiency is improved and the heat of polymerization is easily removed to carry out the reaction smoothly. From the viewpoint, 20 to 150 ° C. is preferable, and 40 to 120 ° C. is more preferable.
  • the reaction time is usually 0.5-4 hours.
  • the completion of the polymerization reaction can be confirmed, for example, by stopping the temperature rise in the reaction system. As a result, the polymer of the ethylenically unsaturated monomer is usually obtained in the state of a hydrogel.
  • cross-linking may be performed by adding a cross-linking agent to the obtained hydrogel polymer and heating it.
  • a cross-linking agent By performing cross-linking after the polymerization, the degree of cross-linking of the hydrogel polymer can be increased to further improve the water absorption characteristics.
  • cross-linking agent for performing post-polymerization cross-linking examples include polyols such as ethylene glycol, propylene glycol, 1,4-butanediol, trimethylolpropane, glycerin, polyoxyethylene glycol, polyoxypropylene glycol, and polyglycerin; Compounds having two or more epoxy groups such as (poly) ethylene glycol diglycidyl ether, (poly) propylene glycol diglycidyl ether, (poly) glycerin diglycidyl ether; Haloepoxide compounds; compounds having two or more isocyanate groups such as 2,4-tolylene diisocyanate, hexamethylene diisocyanate; oxazoline compounds such as 1,2-ethylene bisoxazoline; carbonate compounds such as ethylene carbonate; bis [N, Examples thereof include hydroxyalkylamide compounds such as N-di ( ⁇ -hydroxyethyl)] adipamide.
  • polyols
  • polyglycidyl compounds such as (poly) ethylene glycol diglycidyl ether, (poly) glycerin diglycidyl ether, (poly) glycerin triglycidyl ether, (poly) propylene glycol diglycidyl ether, and polyglycerol polyglycidyl ether are available.
  • the cross-linking agent may be used alone or in combination of two or more.
  • the amount of the cross-linking agent after polymerization may be 30 mmol or less, 10 mmol or less, or 0.01 to 5 mmol per mole of the ethylenically unsaturated monomer from the viewpoint that suitable water absorption characteristics can be easily obtained.
  • the timing of adding the cross-linking agent after polymerization may be after the polymerization of the ethylenically unsaturated monomer used for polymerization, and in the case of multi-stage polymerization, it is preferable to add it after multi-stage polymerization.
  • the post-polymerization cross-linking agent contains water in consideration of heat generation during and after polymerization, retention due to process delay, opening of the system when the cross-linking agent is added, and fluctuation of water content due to addition of water accompanying the addition of the cross-linking agent. From the viewpoint of rate (described later), it is preferable to add in the region of [moisture content immediately after polymerization ⁇ 3% by mass].
  • polymer particles for example, polymer particles having a structural unit derived from an ethylenically unsaturated monomer
  • a drying method for example, (a) in a state where the hydrogel polymer is dispersed in a hydrocarbon dispersion medium, azeotropic distillation is performed by heating from the outside, and the hydrocarbon dispersion medium is refluxed to remove water.
  • examples thereof include (b) a method of taking out the hydrogel polymer by decantation and drying under reduced pressure, and (c) a method of filtering the hydrogel polymer with a filter and drying under reduced pressure.
  • the method (a) is preferably used because of its simplicity in the manufacturing process.
  • the particle size of the water-absorbent resin particles can be adjusted by adjusting the rotation speed of the stirrer during the polymerization reaction, or by adding a flocculant into the system after the polymerization reaction or in the early stage of drying. By adding a flocculant, the particle size of the obtained water-absorbent resin particles can be increased.
  • an inorganic flocculant can be used as the flocculant.
  • the inorganic flocculant for example, powdered inorganic flocculant
  • the aggregating agent is preferably at least one selected from the group consisting of silica, aluminum oxide, talc and kaolin.
  • the flocculant is previously dispersed in a hydrocarbon dispersion medium or water of the same type as that used in the polymerization, and then the hydrogel polymer is mixed under stirring.
  • a method of mixing in a hydrocarbon dispersion medium containing the mixture is preferable.
  • the amount of the flocculant added is preferably 0.001 to 1 part by mass, more preferably 0.005 to 0.5 part by mass, based on 100 parts by mass of the ethylenically unsaturated monomer used for the polymerization. 01 to 0.2 parts by mass is more preferable.
  • the amount of the flocculant added is within the above range, the water-absorbent resin particles having the desired particle size distribution can be easily obtained.
  • the surface portion (surface and vicinity of the surface) of the hydrogel polymer may be surface-crosslinked using a cross-linking agent in the drying step (moisture removing step) or a subsequent step. preferable.
  • a cross-linking agent in the drying step (moisture removing step) or a subsequent step.
  • the surface cross-linking is preferably performed at a timing when the water-containing gel polymer has a specific water content.
  • the time of surface cross-linking is preferably when the water content of the hydrogel polymer is 5 to 50% by mass, more preferably 10 to 40% by mass, and even more preferably 15 to 35% by mass.
  • the water content (mass%) of the water-containing gel polymer is calculated by the following formula.
  • Moisture content [Ww / (Ww + Ws)] x 100
  • Ww A flocculant, a surface cross-linking agent, etc. are mixed in an amount obtained by subtracting the amount of water discharged to the outside of the system by a step such as a drying step from the amount of water contained in the monomer aqueous solution before polymerization in the entire polymerization step.
  • the amount of water in the hydrogel polymer to which the amount of water used as needed is added.
  • Ws A solid content calculated from the amount of materials such as an ethylenically unsaturated monomer, a cross-linking agent, and an initiator that constitute a hydrogel polymer.
  • examples of the surface cross-linking agent include polyols such as ethylene glycol, propylene glycol, 1,4-butanediol, trimethylolpropane, glycerin, polyoxyethylene glycol, polyoxypropylene glycol, and polyglycerin; (poly) ethylene glycol diglycidyl ether.
  • Oxetane compounds carbonate compounds such as ethylene carbonate; hydroxyalkylamide compounds such as bis [N, N-di ( ⁇ -hydroxyethyl)] adipamide and the like.
  • the surface cross-linking agent may be used alone or in combination of two or more.
  • a polyglycidyl compound is preferable, and (poly) ethylene glycol diglycidyl ether, (poly) glycerin diglycidyl ether, (poly) glycerin triglycidyl ether, (poly) propylene glycol diglycidyl ether, and polyglycerol poly At least one selected from the group consisting of glycidyl ether is more preferable.
  • the amount of the surface cross-linking agent used is preferably 0.01 to 20 mmol, preferably 0.05 to 10 to 1 mol of the ethylenically unsaturated monomer used for polymerization, from the viewpoint that suitable water absorption characteristics can be easily obtained. Millimole is more preferable, 0.1 to 5 mmol is further preferable, 0.15 to 1 mmol is particularly preferable, and 0.2 to 0.5 mmol is extremely preferable.
  • the hydrogel polymer obtained by polymerization is preferably surface-treated with a surfactant.
  • the surface treatment with a surfactant is more preferably performed after the above-mentioned surface cross-linking step.
  • a surfactant of HLB 5 or less By treating the surface of the hydrogel polymer after surface cross-linking with a surfactant of HLB 5 or less, the degree of hydrophobicity of the surface of the water-absorbent resin particles can be increased, whereby the gel diffusion aspect ratio is 2.6 or less. Water-absorbent resin particles are likely to be obtained.
  • the particles after undergoing steps such as drying and surface cross-linking, if necessary are similarly surface-treated with a surfactant. A similar effect can be obtained.
  • Examples of the surfactant used for the surface treatment include the same types as the surfactant used during the above-mentioned polymerization. Among them, sucrose fatty acid ester is preferable, and sucrose stearic acid ester is more preferable, from the viewpoint of lowering the gel diffusion aspect ratio.
  • the surface treatment with a surfactant may be, for example, adhering the surfactant to the surface of the hydrogel polymer or the water-absorbent resin particles.
  • a surfactant solution obtained by dissolving the surfactant in a hydrocarbon dispersion medium is mixed with a hydrogel polymer, and then the hydrocarbon dispersion medium is used. Can be done by evaporating and removing.
  • the amount of the surfactant may be, for example, 0.01 to 0.50 parts by mass with respect to 100 parts by mass of the ethylenically unsaturated monomer.
  • the concentration of the surfactant in the surfactant solution may be, for example, 0.1 to 2% by mass.
  • the mixing conditions of the surfactant solution and the hydrogel polymer may be, for example, a temperature of 20 to 140 ° C. and a mixing time of 1 to 60 minutes.
  • surface cross-linking or surface treatment with a surfactant is performed by distilling off water and a hydrocarbon dispersion medium by a known method, drying under heating and reduced pressure, and the like. It is possible to obtain polymer particles which are dried products.
  • the polymerization reaction can be carried out using various stirrers having stirring blades.
  • stirring blade flat plate blades, lattice blades, paddle blades, propeller blades, anchor blades, turbine blades, Faudler blades, ribbon blades, full zone blades, max blend blades and the like can be used.
  • the water-absorbent resin particles according to the present embodiment may be composed of only polymer particles, and for example, a gel stabilizer and 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.), additional components such as a fluidity improver (lubricant) for polymer particles can be further included. Additional components may be located inside the polymer particles, on the surface of the polymer particles, or both.
  • a gel stabilizer and 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.
  • additional components such as a fluidity improver (lubricant) for polymer particles can be further included. Additional components may be located inside the polymer particles, on the surface of the polymer particles, or both.
  • the water-absorbent resin particles may contain a plurality of inorganic particles arranged on the surface of the polymer particles.
  • the inorganic particles can be arranged on the surface of the polymer particles.
  • the inorganic particles may be silica particles such as amorphous silica.
  • the content of the inorganic particles may be in the following range based on the total mass of the polymer particles.
  • the content of the inorganic particles may be 0.05% by mass or more, 0.1% by mass or more, 0.15% by mass or more, or 0.2% by mass or more.
  • the content of the inorganic particles may be 5.0% by mass or less, 3.0% by mass or less, 1.0% by mass or less, 0.5% by mass or less, or 0.3% by mass or less.
  • the inorganic particles here usually have a minute size as compared with the size of the polymer particles.
  • the average particle size of the inorganic particles may be 0.1 to 50 ⁇ m, 0.5 to 30 ⁇ m, or 1 to 20 ⁇ m.
  • the average particle size can be measured by the pore electric resistance method or the laser diffraction / scattering method depending on the characteristics of the particles.
  • the water-absorbent resin particles according to the present embodiment have excellent absorbency of body fluids such as urine and blood.
  • body fluids such as urine and blood.
  • sanitary products such as disposable diapers, sanitary napkins and tampons, pet sheets, dog or cat toilet formulations and the like. It can be applied to fields such as animal excrement treatment materials.
  • the water-absorbent resin particles according to this embodiment can be suitably used for an absorber.
  • the absorber according to the present embodiment contains the water-absorbent resin particles according to the present embodiment.
  • the content of the water-absorbent resin particles in the absorber is 100 to 1000 g (that is, 100 to 1000 g / m) per square meter of the absorber from the viewpoint of obtaining sufficient liquid absorption performance when the absorber is used in an absorbent article. 2 ) is preferable, more preferably 150 to 800 g / m 2 , still more preferably 200 to 700 g / m 2 .
  • the content is preferably 100 g / m 2 or more.
  • the content is preferably 1000 g / m 2 or less.
  • the absorber may further include, for example, a fibrous material in addition to the water-absorbent resin particles.
  • the absorber may be, for example, a mixture containing water-absorbent resin particles and a fibrous substance.
  • the mass ratio of the water-absorbent resin particles in the absorber may be 2% to 100%, preferably 10% to 80%, and preferably 20% to 80% with respect to the total of the water-absorbent resin particles and the fibrous material. More preferably, it is 70%.
  • the structure of the absorber may be, for example, a form 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 a sheet or layer. It may be in a form or in any other form.
  • the fibrous material examples include finely pulverized wood pulp, cotton, cotton linter, rayon, cellulosic fibers such as cellulose acetate, and synthetic fibers such as polyamide, polyester, and polyolefin. Further, the fibrous material may be a mixture of the above-mentioned fibers.
  • 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, and 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 compounding of a base polymer such as amorphous polypropylene and a tackifier, a plasticizer, an antioxidant and the like.
  • Adhesive emulsions include, for example, 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. Be done. These adhesive binders may be used alone or in combination of two or more.
  • the absorber according to the present embodiment may further contain additives such as inorganic particles (for example, amorphous silica), deodorants, pigments, dyes, antibacterial agents, fragrances, and adhesives. These additives can impart various functions to the absorber.
  • the absorber may contain inorganic particles in addition to the inorganic particles in the water-absorbent resin particles. Examples of the inorganic particles include silicon dioxide, zeolite, kaolin, clay and the like.
  • the shape of the absorber according to the present embodiment is not particularly limited, and may be, for example, a sheet shape.
  • the thickness of the absorber (for example, the thickness of the sheet-shaped absorber) may be, for example, 0.1 to 20 mm and 0.3 to 15 mm.
  • the absorbent article according to the present embodiment may include, for example, a core wrap, a liquid permeable top sheet, and a liquid permeable back sheet in addition to the absorbent body.
  • the core wrap retains the shape of the absorber.
  • the liquid permeable top sheet is arranged on the outermost side on the side where the liquid to be absorbed enters.
  • the liquid impermeable back sheet is arranged on the outermost side opposite to the side where the liquid to be absorbed enters.
  • absorbent articles examples include diapers (for example, paper diapers), toilet training pants, incontinence pads, sanitary products (sanitary napkins, tampons, etc.), sweat pads, pet sheets, toilet members, animal excrement treatment materials, and the like. ..
  • FIG. 6 is a cross-sectional view showing an example of an absorbent article.
  • the absorbent article 100 shown in FIG. 6 includes an absorbent body 10, core wraps 20a and 20b, a liquid permeable top sheet 30, and a liquid permeable back sheet 40.
  • the liquid permeable back sheet 40, the core wrap 20b, the absorbent body 10, the core wrap 20a, and the liquid permeable top sheet 30 are laminated in this order.
  • FIG. 6 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 a water-absorbent resin particle 10a 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. 6) 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. 6) in contact with the absorber 10.
  • the absorber 10 is arranged between the core wrap 20a and the core wrap 20b.
  • the core wrap 20a and the core wrap 20b have, for example, a main surface having the same size as the absorber 10.
  • the core wrap By using the core wrap, it is possible to maintain the shape retention of the absorber and prevent the water-absorbent resin particles and the like constituting the absorber from falling off and flowing.
  • the core wrap include non-woven fabrics, woven fabrics, tissues, synthetic resin films having liquid permeation holes, net-like sheets having a mesh, and the like, and from the viewpoint of economy, a tissue made by wet-molding crushed pulp is preferable. Used.
  • the liquid permeable top sheet 30 is arranged on the outermost side on the side where the liquid to be absorbed enters.
  • the liquid permeable top sheet 30 is arranged on the core wrap 20a in contact with the core wrap 20a.
  • the liquid permeable back sheet 40 is arranged on the outermost side of the absorbent article 100 on the opposite side of the liquid permeable top sheet 30.
  • the liquid impermeable back sheet 40 is arranged under the core wrap 20b in contact with the core wrap 20b.
  • the liquid permeable top sheet 30 and the liquid permeable back sheet 40 have, for example, a main surface wider than the main surface of the absorber 10, and the liquid permeable top sheet 30 and the liquid permeable back sheet 40 have.
  • the outer edge extends around the absorber 10 and the core wraps 20a, 20b.
  • liquid permeable top sheet 30 examples include non-woven fabrics and porous sheets.
  • non-woven fabric examples include thermal bond non-woven fabric, air-through non-woven fabric, resin-bond non-woven fabric, spun-bond non-woven fabric, melt-blow non-woven fabric, spunbond / melt-blow / spunbond non-woven fabric, air-laid non-woven fabric, spunlace non-woven fabric, point-bond non-woven fabric and the like.
  • thermal bond non-woven fabrics, air-through non-woven fabrics, spunbond non-woven fabrics, and spunbond / melt blow / spunbond non-woven fabrics are preferably used.
  • a resin or fiber known in the art can be used, and polyethylene (from the viewpoint of liquid permeability, flexibility and strength when used in an absorbent article, polyethylene ( Polyester such as PE), polypropylene (PP), polyethylene terephthalate (PET), polytrimethylene terephthalate (PTT), polyester such as polyethylene naphthalate (PEN), polyamide such as nylon, rayon, other synthetic resins or fibers, Examples include cotton, silk, linen and pulp (polyethylene) fibers.
  • synthetic fibers are preferably used from the viewpoint of increasing the strength of the liquid permeable top sheet 30, and among them, polyolefin and polyester are preferable. These materials may be used alone or in combination of two or more kinds of materials.
  • the non-woven fabric used for the liquid permeable top sheet 30 has appropriate hydrophilicity from the viewpoint of improving the liquid absorption performance of the absorbent article. From this point of view, it is preferable that the hydrophilicity when measured according to the "hydrophilicity of the non-woven fabric" described in International Publication No. 2011/086843 (based on the pulp and paper test method No. 68 (2000)) is 5 to 200. Those of 10 to 150 are more preferable.
  • the non-woven fabric having such hydrophilicity among the above-mentioned non-woven fabrics, those in which the material itself exhibits appropriate hydrophilicity such as rayon fiber may be used, and hydrophobic chemistry such as polyolefin fiber and polyester fiber may be used.
  • a fiber may be used which has been hydrophilized by a known method to impart an appropriate degree of hydrophilicity.
  • a method for hydrophilizing the chemical fiber for example, in a spunbonded non-woven fabric, a method in which a hydrophobic chemical fiber mixed with a hydrophilic agent is obtained by a spunbonding method, or a spunbonded non-woven fabric using a hydrophobic chemical fiber is used.
  • a method of accommodating a hydrophilic agent when producing the above a method of impregnating a hydrophilic agent after obtaining a spunbonded nonwoven fabric with hydrophobic chemical fibers, and the like.
  • hydrophilizing agent examples include anionic surfactants such as aliphatic sulfonates and higher alcohol sulfates, cationic surfactants such as quaternary ammonium salts, polyethylene glycol fatty acid esters, polyglycerin fatty acid esters, and sorbitan fatty acids.
  • anionic surfactants such as esters, silicone-based surfactants such as polyoxyalkylene-modified silicones, and stain-releasing agents made of polyester-based, polyamide-based, acrylic-based, and urethane-based resins are used.
  • the non-woven fabric used for the liquid permeable top sheet 30 is appropriately bulky from the viewpoint of imparting good liquid permeability, flexibility, strength and cushioning property to the absorbent article and increasing the liquid penetration rate of the absorbent article. It is preferably high and has a large amount of grain.
  • the basis weight of the non-woven fabric is preferably 5 to 200 g / m 2 , more preferably 8 to 150 g / m 2 , and even more preferably 10 to 100 g / m 2 .
  • the thickness of the non-woven fabric is preferably 20 to 1400 ⁇ m, more preferably 50 to 1200 ⁇ m, and even more preferably 80 to 1000 ⁇ m.
  • the liquid impermeable back sheet 40 prevents the liquid absorbed by the absorber 10 from leaking from the back sheet 40 side to the outside.
  • the liquid impermeable back sheet 40 is made of a liquid impermeable film mainly composed of a polyolefin resin such as polyethylene (PE) and polypropylene (PP), a breathable resin film, and a non-woven fabric such as spunbond or spunlace.
  • PE polyethylene
  • PP polypropylene
  • a non-woven fabric such as spunbond or spunlace.
  • a composite film to which the above resin films are bonded, a spunbond / melt blow / spunbond (SMS) nonwoven fabric in which a water-resistant meltblown non-woven fabric is sandwiched between high-strength spunbond nonwoven fabrics can be used.
  • the back sheet 40 should be a resin film having a grain size of 10 to 50 g / m 2 mainly made of low density polyethylene (LDPE) resin. Can be done. In addition, when a breathable material is used, stuffiness during wearing is reduced, and discomfort given to the wearer can be reduced.
  • LDPE low density polyethylene
  • the magnitude relationship between the absorbent body 10, the core wraps 20a and 20b, the liquid permeable top sheet 30, and the liquid permeable back 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. 6, the absorber may be sandwiched by a plurality of core wraps, and the absorber may be sandwiched by one core wrap. May be coated.
  • the absorber 10 may be adhered to the liquid permeable top sheet 30.
  • the liquid is guided to the absorbent body more smoothly, so that it is easy to obtain an excellent absorbent article by preventing liquid leakage.
  • the absorber 10 is sandwiched or covered by the core wrap, it is preferable that at least the core wrap and the liquid permeable top sheet 30 are adhered to each other, and it is more preferable that the core wrap and the absorber 10 are adhered to each other.
  • Examples of the bonding method include a method of applying a hot melt adhesive to the liquid permeable top sheet 30 at predetermined intervals in the width direction in a vertical stripe shape, a spiral shape, or the like, and bonding starch or carboxymethyl cellulose. , Polyvinyl alcohol, polyvinylpyrrolidone and other methods of bonding using a water-soluble binder selected from water-soluble polymers.
  • a method of adhering by heat-sealing may be adopted.
  • the water-retaining amount of the physiological saline is 15 to 50 g / g, and the water absorption of the physiological saline under a load of 4.14 kPa is 13 mL / g or more. It may also include selecting water-absorbent resin particles having a gel diffusion aspect ratio of 2.6 or less as measured by the method described above.
  • the above-mentioned production method may include a step of measuring the water retention amount of the physiological saline in the water-absorbent resin particles, the water absorption amount with respect to the physiological saline under a load of 4.14 kPa, and the gel diffusion aspect ratio.
  • the properties of the water-absorbent resin particles to be selected may further satisfy the above-mentioned aspects of the water-absorbent resin particles (for example, gel outflow rate in a specific range).
  • Another aspect of this embodiment relates to a method for measuring the gel diffusion aspect ratio of water-absorbent resin particles.
  • the specific embodiment of the measurement method is as described above.
  • the gel diffusion aspect ratio measured by the method according to the present embodiment can be used as an index of the permeation rate when the water-absorbent resin particles are used as the absorber.
  • the gel diffusion aspect ratio relates to the diffusivity of a gel in which water-absorbent resin particles are swollen 30 times in advance, and is not simply caused by the difficulty of gel blocking by the above-mentioned measuring method. Penetration characteristics can be evaluated.
  • the number of times of adding the blue saline solution is set to 4. Even when the number of injections is less than 4, the gel diffusion aspect ratio is substantially constant, but the number of additions is determined in order to ensure the stability and reproducibility of the operation.
  • Yet another aspect of this embodiment is a water-absorbent resin having a water-retaining amount of 15 to 50 g / g and a water-absorbing amount of 13 mL / g or more with respect to the physiological saline under a load of 4.14 kPa. It can also be said that it is a method for improving the permeation rate of the absorber containing the water-absorbent resin particles, which comprises reducing the gel diffusion aspect ratio in the particles.
  • the gel diffusion aspect ratio may be reduced to, for example, 2.6 or less.
  • the method for measuring the gel diffusion aspect ratio is as described above. A specific measuring method of the water retention amount measuring method of the physiological saline and the water absorption measuring method for the physiological saline under load will be shown in Examples described later.
  • the method for improving the permeation rate of the absorber may further include, for example, adjusting the gel outflow ratio to 30% or less, adjusting the physiological saline water retention amount to 30 g / g or more, and the like.
  • An example of a specific method for producing the water-absorbent resin particles having these predetermined properties is as described above.
  • the gel diffusion aspect ratio of the water-absorbent resin particles can be reduced, for example, 2.6 or less, for example, by selecting production conditions so as to increase the hydrophobicity of the surface of the water-absorbent resin particles.
  • the present embodiment it is possible to provide a method for producing an absorber using the water-absorbent resin particles obtained by the above-mentioned method for producing water-absorbent resin particles.
  • the method for producing an absorber according to the present embodiment includes a particle manufacturing step for obtaining water-absorbent resin particles by the above-mentioned method for producing 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 particle manufacturing step.
  • the present embodiment it is possible to provide a method for producing an absorbent article using the absorber obtained by the above-mentioned method for producing an absorber.
  • 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.
  • Example 1 A round-bottomed cylindrical separable flask having an inner diameter of 11 cm and an internal volume of 2 L equipped with a reflux condenser, a dropping funnel, a nitrogen gas introduction pipe, and a stirrer was prepared. As the stirrer, a stirrer having a stirrer blade having four inclined paddle blades having a blade diameter of 5 cm in two stages was used.
  • n-heptane 293 g of n-heptane and 0.736 g of a maleic anhydride-modified ethylene-propylene copolymer (manufactured by Mitsui Chemicals, Inc., High Wax 1105A) as a dispersant were put into the flask and mixed.
  • the dispersant was dissolved in n-heptane by heating the mixture to 80 ° C. while stirring the mixture in the flask with a stirrer. The formed solution was cooled to 50 ° C.
  • the first-stage aqueous solution was added to the n-heptane solution containing the dispersant in the flask, and the formed reaction solution was stirred for 10 minutes.
  • a surfactant solution prepared by dissolving 0.736 g of sucrose stearic acid ester (Mitsubishi Chemical Foods Co., Ltd., Ryoto Sugar Ester S-370, HLB: 3), which is a surfactant, in 6.62 g of n-heptane. I prepared it.
  • the surfactant solution was added to the flask, the rotation speed of the stirrer was set to 550 rpm, and the inside of the system was sufficiently replaced with nitrogen while stirring the reaction solution.
  • the flask was immersed in a water bath at 70 ° C. to raise the temperature of the reaction solution, and the polymerization reaction was allowed to proceed for 60 minutes to obtain a first-stage polymerization slurry solution.
  • the first-stage polymer slurry solution in the flask was cooled to 25 ° C., and the entire amount of the second-stage aqueous solution was added thereto. After replacing the inside of the flask with nitrogen for 30 minutes, the flask was again immersed in a water bath at 70 ° C. to raise the temperature of the reaction solution, and a water-containing gel-like polymer was obtained by the second-stage polymerization reaction for 60 minutes. ..
  • 0.589 g of a 45% by mass diethylenetriamine-5 sodium acetate aqueous solution was added to the hydrogel polymer after the second stage polymerization under stirring. Then, the flask was immersed in an oil bath set at 125 ° C., and 216.7 g of water was extracted from the system by azeotropic distillation of n-heptane and water. Next, 4.42 g of an aqueous solution having a concentration of 2% by mass containing ethylene glycol diglycidyl ether (0.507 mmol) as a surface cross-linking agent was added to the flask, and the temperature was maintained at 83 ° C. for 2 hours.
  • a surfactant solution was prepared in which 0.037 g of sucrose stearic acid ester (Mitsubishi Chemical Foods Co., Ltd., Ryoto Sugar Ester S-370, HLB: 3), which is a surfactant, was dissolved in 6.62 g of n-heptane. The surfactant solution was further added to the flask.
  • sucrose stearic acid ester Mitsubishi Chemical Foods Co., Ltd., Ryoto Sugar Ester S-370, HLB: 3
  • polymer particles (dried product) were obtained by removing n-heptane by drying at 125 ° C. After passing the polymer particles through a sieve having an opening of 850 ⁇ m, 0.2% by mass of amorphous silica (Oriental Silicas Corporation, Toxile NP-S) with respect to the mass of the polymer particles is used as the polymer particles. By mixing, 229.0 g of water-absorbent resin particles were obtained. The medium particle size of the water-absorbent resin particles was 348 ⁇ m.
  • Example 2 In the preparation of the first-stage aqueous solution, the amount of potassium persulfate added was 0.0736 g (0.272) without using 2,2'-azobis (2-amidinopropane) dihydrochloride as the water-soluble radical polymerization initiator. The amount of ethylene glycol diglycidyl ether added as an internal cross-linking agent was changed to 0.0156 g (0.090 mmol), and the water-soluble radical polymerization initiator was used in the preparation of the second-stage aqueous solution.
  • Example 1 except that the amount of water extracted by distillation was set to 254.5 g and the amount of amorphous silica mixed with the polymer particles was changed to 0.5% by mass with respect to the mass of the polymer particles. In the same manner as above, 231.8 g of water-absorbent resin particles were obtained. The medium particle size of the water-absorbent resin particles was 368 ⁇ m.
  • Example 3 232.5 g of water-absorbent resin particles were obtained in the same manner as in Example 1 except that the amount of water extracted by azeotropic distillation of n-heptane and water was 207.9 g.
  • the medium particle size of the water-absorbent resin particles was 360 ⁇ m.
  • Example 4 Round-bottomed cylindrical separable flask with four side wall baffles with an inner diameter of 11 cm and an internal volume of 2 L, equipped with a reflux condenser, a dropping funnel, a nitrogen gas introduction pipe, and a stirrer (baffle width: 7 mm, baffle length:: 10 cm) was prepared.
  • the stirrer was equipped with a stirrer blade having two stages of four inclined paddle blades having a blade diameter of 50 mm and surface-treated with fluororesin.
  • n-heptane n-heptane
  • sorbitan monolaurate trade name: Nonion LP-20R, HLB value 8.6, manufactured by NOF CORPORATION
  • the sorbitan monolaurate was dissolved in n-heptane by heating the mixture to 50 ° C. while stirring the mixture in the flask with a stirrer.
  • the formed solution was cooled to 40 ° C.
  • the obtained aqueous monomer solution was added to the flask containing the solution containing sorbitan monolaurate, and the inside of the system was sufficiently replaced with nitrogen.
  • the polymerization reaction was allowed to proceed by holding the reaction solution in the flask in a warm water bath at 70 ° C. for 60 minutes while stirring at a rotation speed of 700 rpm.
  • a dispersion was prepared by dispersing 0.092 g of amorphous silica (Carplex # 80 manufactured by Evonik Degussa Japan Co., Ltd.) in 100 g of n-heptane. The dispersion was added to the reaction solution containing the hydrogel polymer produced by the polymerization reaction, and the reaction solution was stirred for 10 minutes. The flask was immersed in an oil bath at 125 ° C., and 104 g of water was extracted from the system by azeotropic distillation.
  • amorphous silica Carplex # 80 manufactured by Evonik Degussa Japan Co., Ltd.
  • a surfactant solution is prepared by dissolving 0.037 g of sucrose stearic acid ester (Mitsubishi Chemical Foods Co., Ltd., Ryoto Sugar Ester S-370, HLB: 3), which is a surfactant, in 6.62 g of n-heptane. did. The surfactant solution was added to the flask.
  • the reaction solution in the flask was heated to 125 ° C. to evaporate n-heptane to obtain a dried product of polymer particles.
  • This dried product was passed through a sieve having an opening of 850 ⁇ m to obtain 90.5 g of water-absorbent resin particles.
  • the medium particle size of the water-absorbent resin particles was 420 ⁇ m.
  • Example 5 90.1 g of water-absorbent resin particles were obtained in the same manner as in Example 4 except that the amount of water extracted by azeotropic distillation of n-heptane and water was 112.3 g.
  • the medium particle size of the water-absorbent resin particles was 403 ⁇ m.
  • the amount of potassium persulfate added was changed to 0.103 g (0.381 mmol) without using 2,2'-azobis (2-amidinopropane) dihydrochloride, and co-boiling of n-heptane and water.
  • 228.4 g of water-absorbent resin particles were obtained in the same manner as in Example 1 except that the amount of water extracted by distillation was 271.0 g and no surfactant was added after the surface cross-linking step.
  • the medium particle size of the water-absorbent resin particles was 351 ⁇ m.
  • Comparative Example 3 231.2 g of water-absorbent resin particles were obtained in the same manner as in Comparative Example 1 except that the amount of water extracted by azeotropic distillation of n-heptane and water was 257.7 g.
  • the medium particle size of the water-absorbent resin particles was 352 ⁇ m.
  • the gel diffusion aspect ratio was measured by the following method. The measurement was performed in an environment of 25 ⁇ 2 ° C. and a humidity of 50 ⁇ 10%. In a beaker having an internal volume of 500 ml, 290 g of physiological saline was stirred at 600 rpm using a stirrer tip (8 mm ⁇ ⁇ 30 mm, without ring). A swelling gel was obtained by adding 10 g of water-absorbent resin particles to the physiological saline and allowing the water-absorbent resin particles to absorb water for 2 minutes while continuing stirring.
  • a transparent container with an opening at the top whose outer dimensions are width 21 cm, height 16.5 cm, and thickness 2.5 cm, and whose inner dimensions of the space are width 20 cm, height 16 cm, and thickness 1.5 cm, is installed horizontally. Then, 200 g of the swollen gel was evenly charged into the transparent container.
  • a lid having a piston portion having a width of 19.8 cm, a height of 10 cm, and a width of 1.3 cm and a total mass of 0.45 kg is fitted in a transparent container, and the bottom surface of the piston portion is placed on a swollen gel so as to be horizontal. I put it. An additional 1.35 kg weight was placed on the lid for 30 seconds to shape the swollen gel filled in the transparent container. After 30 seconds, the lid was removed from the transparent container.
  • the remaining 100 g of the swelling gel was added to the transparent container, and the shape of the entire swelling gel was adjusted again using the lid and the weight in the same manner as described above to form a swelling gel layer consisting of 300 g of the swelling gel.
  • a blue physiological saline solution containing Blue No. 1 at a concentration of 0.005% by mass was prepared.
  • the tip of the burette was placed at a position 3 cm above the center of the upper surface of the swelling gel layer, and 10 ml of blue physiological saline was poured into the swelling gel layer at 2 ml / sec.
  • the blue saline was added at 10-minute intervals in the same manner three more times, for a total of four times.
  • Five minutes after the start of the fourth injection of blue physiological saline, the maximum length of the stained area in the horizontal direction and the maximum length in the vertical direction were measured from both side surfaces (side surfaces having a width of 20 cm) of the transparent container.
  • the gel diffusion aspect ratio was calculated by the following formula using the value on the side surface having the longer maximum length in the vertical direction among the two side surfaces having a width of 20 cm. The results are shown in Table 1.
  • Gel diffusion aspect ratio L1 / L2
  • L1 Maximum length in the horizontal direction
  • L2 Maximum length in the vertical direction
  • the cotton bag was dehydrated for 1 minute using a dehydrator (manufactured by Kokusan Co., Ltd., product number: H-122) set to have a centrifugal force of 167 G.
  • the mass Wa (g) of the cotton bag containing the swollen gel after dehydration was measured.
  • the same operation was performed without adding the water-absorbent resin particles, and the empty mass Wb (g) of the cotton bag when wet was measured.
  • the gel outflow ratio was measured in an environment of room temperature (25 ⁇ 2 ° C.) and humidity of 50 ⁇ 10%. 58 g of physiological saline at 25 ° C. was stirred in a glass beaker with a stirrer tip (length 3.0 cm, diameter 8 mm) at 600 rpm, and 2 g of water-absorbent resin particles were charged therein. After confirming that the water-absorbent resin particles had swollen and the vortices on the liquid surface had converged, stirring was stopped.
  • the sample container made of acrylic resin
  • the tubing test jig for Ez-test manufactured by Shimadzu Corporation
  • a 5 mm ⁇ perforated disc made of aluminum
  • the tubular body 41 having the bottom portion 41B forming the opening 41A is fixed to the clamp so that the longitudinal direction of the tubular body 41 is vertical and the bottom portion 41B is downward (FIG. 3).
  • an aluminum disc 42 having a diameter of 4.9 cm and a thickness of 3.0 mm having a through hole H formed in the center on the bottom 41B is placed horizontally on the main surface of the disc 42. Arrange in the same direction (Fig. 3).
  • the through hole H has a wall surface inclined with respect to the main surface of the disc 42 so that the through hole H is the narrowest at the central position in the thickness direction of the disc 42.
  • (3) 20 g of the swelling gel 45 formed by the water-absorbent resin particles absorbing the physiological saline is placed in the tubular body 41 and placed on the disc 42.
  • the swollen gel 45 has a mass 30 times that of the mass of the water-absorbent resin particles before absorbing the physiological saline.
  • the swelling gel 45 is compressed for 30 seconds by gently placing a first cylindrical weight 46 having a mass of 500 g and a diameter of 4.9 cm made of stainless steel on the swelling gel 45 in the tubular body 41 (FIG. 4). (5) By gently placing a cylindrical second weight 47 having a mass of 1500 g and a diameter of 4.9 cm on the first weight 46, the swelling gel 45 is further compressed with a total load of 2000 g (FIG. 5). .. (6) The mass W (g) of the swelling gel 45 flowing out from the through hole H of the disk 42 is measured while the swelling gel 45 is compressed for 30 seconds with a load of 2000 g.
  • the swelling gel 45 that has flowed out often falls, but when a part or all of the swelling gel 45 that has flowed out is held in a state of hanging from the through hole H, it is present from the lower main surface of the disk 42.
  • the mass W of the swelling gel 45 that flowed out was measured, including the swelling gel that hung down at the lower position. (7)
  • the amount of physiological saline water absorption under a load of 4.14 kPa was measured using the measuring device outlined in FIG. 7. The measurement was performed twice for one type of water-absorbent resin particles, and the average value was obtained.
  • the measuring device includes a burette unit 1, a clamp 3, a conduit 5, a gantry 11, a measuring table 13, and a measuring unit 4 placed on the measuring table 13.
  • the burette portion 1 includes a burette tube 21 on which a scale is described, a rubber stopper 23 for sealing the upper opening of the burette tube 21, a cock 22 connected to the tip of the lower portion of the burette tube 21, and a lower portion of the burette tube 21. It has an air introduction pipe 25 and a cock 24 connected to the burette.
  • the burette portion 1 is fixed by a clamp 3.
  • the flat plate-shaped measuring table 13 has a through hole 13a having a diameter of 2 mm formed in the central portion thereof, and is supported by a frame 11 having a variable height.
  • the through hole 13a of the measuring table 13 and the cock 22 of the burette portion 1 are connected by a conduit 5.
  • the inner diameter of the conduit 5 is 6 mm.
  • the measuring unit 4 has a cylinder 31 made of plexiglass, a polyamide mesh 32 adhered to one opening of the cylinder 31, and a weight 33 movable in the vertical direction in the cylinder 31.
  • the cylinder 31 is placed on the measuring table 13 via the polyamide mesh 32.
  • the inner diameter of the cylinder 31 is 20 mm.
  • the opening of the polyamide mesh 32 is 75 ⁇ m (200 mesh).
  • the weight 33 has a diameter of 19 mm and a mass of 119.6 g, and a load of 4.14 kPa (0.6 psi) can be applied to the water-absorbent resin particles 10a uniformly arranged on the polyamide mesh 32 as described later. it can.
  • the physiological saline water absorption capacity under a load of 4.14 kPa was measured by the measuring device shown in FIG. 7 in a room at 25 ° C.
  • the cock 22 and the cock 24 of the burette portion 1 were closed, and 0.9 mass% physiological saline adjusted to 25 ° C. was put into the burette tube 21 through the opening at the upper part of the burette tube 21.
  • the cock 22 and the cock 24 were opened.
  • the inside of the conduit 5 was filled with 0.9% by mass saline solution 50 to prevent air bubbles from entering.
  • the height of the measuring table 13 was adjusted so that the height of the water surface of the 0.9% by mass saline solution that reached the inside of the through hole 13a was the same as the height of the upper surface of the measuring table 13. After the adjustment, the height of the water surface of the physiological saline solution 50 in the burette tube 21 was read by the scale of the burette tube 21, and the position was set as the zero point (reading value at 0 seconds).
  • the medium particle size of the particles was measured in an environment of room temperature (25 ⁇ 2 ° C.) and humidity of 50 ⁇ 10% according to the following procedure. That is, from the top of the JIS standard sieve, a sieve with a mesh size of 600 ⁇ m, a sieve with a mesh size of 500 ⁇ m, a sieve with a mesh size of 425 ⁇ m, a sieve with a mesh size of 300 ⁇ m, a sieve with a mesh size of 250 ⁇ m, a sieve with a mesh size of 180 ⁇ m, and a sieve with a mesh size of 150 ⁇ m. , And the saucer in that order.
  • water-absorbent resin particles of the examples were excellent in the permeation rate of the absorber.
  • Swelling gel 46 ... First weight, 47 ... Second weight, 50 ... Physiological saline , 51 ... transparent container, 52 ... lid, 53 ... piston part, 54 ... swollen gel layer, 55 ... burette, 56 ... dyed area, 100 ... absorbent article, H ... through hole.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Health & Medical Sciences (AREA)
  • Organic Chemistry (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Heart & Thoracic Surgery (AREA)
  • Animal Behavior & Ethology (AREA)
  • Engineering & Computer Science (AREA)
  • Biomedical Technology (AREA)
  • Analytical Chemistry (AREA)
  • Vascular Medicine (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Epidemiology (AREA)
  • General Health & Medical Sciences (AREA)
  • Public Health (AREA)
  • Veterinary Medicine (AREA)
  • Medicinal Chemistry (AREA)
  • Polymers & Plastics (AREA)
  • Absorbent Articles And Supports Therefor (AREA)

Abstract

Des particules de résine absorbant l'eau qui ont une quantité de rétention d'eau de 15 à 50 g/g par rapport à une solution saline, une quantité d'absorption d'eau de 13 mL/g ou plus par rapport à une solution saline sous une charge de 4,14 kPa, et un rapport d'aspect de diffusion de gel de 2,6 ou moins tel que mesuré avec un procédé comprenant les étapes (1), (2), (3), (4), (5), (6), et (7) dans cet ordre sont divulguées.
PCT/JP2020/033753 2019-09-09 2020-09-07 Particules de résine absorbant l'eau WO2021049450A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP2021545518A JPWO2021049450A1 (fr) 2019-09-09 2020-09-07

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2019-163910 2019-09-09
JP2019163910 2019-09-09

Publications (1)

Publication Number Publication Date
WO2021049450A1 true WO2021049450A1 (fr) 2021-03-18

Family

ID=74867042

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/JP2020/033753 WO2021049450A1 (fr) 2019-09-09 2020-09-07 Particules de résine absorbant l'eau

Country Status (2)

Country Link
JP (1) JPWO2021049450A1 (fr)
WO (1) WO2021049450A1 (fr)

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2003088552A (ja) * 2001-09-19 2003-03-25 Sumitomo Seika Chem Co Ltd 吸収体およびそれを用いた吸収性物品
WO2008120742A1 (fr) * 2007-03-29 2008-10-09 Nippon Shokubai Co., Ltd. Absorbant d'eau particulaire et son procédé de fabrication
WO2014038324A1 (fr) * 2012-09-10 2014-03-13 住友精化株式会社 Résine d'absorption d'eau, corps d'absorption d'eau, et produit d'absorption d'eau
WO2016006135A1 (fr) * 2014-07-11 2016-01-14 住友精化株式会社 Procédé de production d'une résine absorbant l'eau
WO2019111812A1 (fr) * 2017-12-08 2019-06-13 Ｓｄｐグローバル株式会社 Particules de résine absorbante ainsi que procédé de fabrication de celles-ci, et corps absorbant ainsi qu'article absorbant

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2003088552A (ja) * 2001-09-19 2003-03-25 Sumitomo Seika Chem Co Ltd 吸収体およびそれを用いた吸収性物品
WO2008120742A1 (fr) * 2007-03-29 2008-10-09 Nippon Shokubai Co., Ltd. Absorbant d'eau particulaire et son procédé de fabrication
WO2014038324A1 (fr) * 2012-09-10 2014-03-13 住友精化株式会社 Résine d'absorption d'eau, corps d'absorption d'eau, et produit d'absorption d'eau
WO2016006135A1 (fr) * 2014-07-11 2016-01-14 住友精化株式会社 Procédé de production d'une résine absorbant l'eau
WO2019111812A1 (fr) * 2017-12-08 2019-06-13 Ｓｄｐグローバル株式会社 Particules de résine absorbante ainsi que procédé de fabrication de celles-ci, et corps absorbant ainsi qu'article absorbant

Also Published As

Publication number Publication date
JPWO2021049450A1 (fr) 2021-03-18

Similar Documents

Publication Publication Date Title
WO2020184389A1 (fr) Particules de résine absorbant l'eau
WO2020184394A1 (fr) Particule de résine absorbant l'eau, absorbeur, article absorbant, procédé de mesure de taux de rétention de perméation de particule de résine absorbant l'eau, et procédé de production de particule de résine absorbant l'eau
JP6828222B1 (ja) 吸水性樹脂粒子、吸収性物品、吸水性樹脂粒子を製造する方法、及び吸収体の加圧下での吸収量を高める方法
WO2020184386A1 (fr) Particules de résine absorbant l'eau, article absorbant, procédé de fabrication de particules de résine absorbant l'eau, procédé pour faciliter la perméation d'une solution saline physiologique dans un corps absorbant
WO2020184387A1 (fr) Particules de resine hydro-absorbantes, procede de production de celles-ci, corps absorbant ainsi qu'article absorbant
WO2020184395A1 (fr) Particules de resine hydro-absorbantes, procede de production de celles-ci, corps absorbant, article absorbant ainsi que procede de regulation de la vitesse de penetration
EP3896120A1 (fr) Particules de résine absorbantes, corps absorbant, et article absorbant
EP3896119A1 (fr) Particules de résine absorbante, et article absorbant
JPWO2020122219A1 (ja) 吸水性樹脂粒子、吸収体、吸収性物品、及び液吸引力測定方法
JPWO2020122202A1 (ja) 吸収性物品
JP6856826B1 (ja) 吸水性樹脂粒子
WO2020218167A1 (fr) Particules de résine absorbante
WO2020184393A1 (fr) Particules de résine absorbante, corps absorbant, et article absorbant
WO2020218160A1 (fr) Particules de résine absorbant l'eau, absorbant et article absorbant
JP6710303B1 (ja) 吸収性物品及びその製造方法
WO2020218168A1 (fr) Particules de resine absorbante, corps absorbant et article absorbant
WO2020184392A1 (fr) Particules de resine hydro-absorbantes et procede de production de celles-ci
US20220015958A1 (en) Water absorbent resin particles and absorbent article
WO2021049450A1 (fr) Particules de résine absorbant l'eau
JP2021102137A (ja) 吸収体、吸収性物品、及び、浸透速度の調整方法
JP6752320B2 (ja) 吸収性物品及びその製造方法
JP6775051B2 (ja) 吸収性物品
JP6775050B2 (ja) 吸収性物品
WO2020218166A1 (fr) Particules de resine absorbante
JP6889811B2 (ja) 吸水性樹脂粒子、吸収性物品、吸水性樹脂粒子を製造する方法、及び吸収性物品の液漏れを抑制する方法

Legal Events

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

Ref document number: 20862642

Country of ref document: EP

Kind code of ref document: A1

ENP Entry into the national phase

Ref document number: 2021545518

Country of ref document: JP

Kind code of ref document: A

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 20862642

Country of ref document: EP

Kind code of ref document: A1