초록 ▼

The present invention provides a method for producing water-absorbing resin particles having high equilibrium swelling capacity, a high water-absorption rate or high initial swelling capacity, and an appropriate particle size that achieves good handling performance; water-absorbing resin particles o

The present invention provides a method for producing water-absorbing resin particles having high equilibrium swelling capacity, a high water-absorption rate or high initial swelling capacity, and an appropriate particle size that achieves good handling performance; water-absorbing resin particles obtained by the method; and a water blocking material and an absorbent article which include the water-absorbing resin particles. The present invention is a method for producing water-absorbing resin particles, which comprises: preparing a hydrogel polymer by reversed-phase suspension polymerization of a water-soluble ethylenically unsaturated monomer in a hydrocarbon solvent in the absence of an internal crosslinking agent but in the presence of a surfactant with an HLB of 8 to 12; carrying out a post-crosslinking reaction of the hydrogel polymer whose moisture content is adjusted to 30 to 110 mass % based on a water-soluble ethylenically unsaturated monomer component that composes the hydrogel polymer.

대표청구항 ▼

1. A method for producing water-absorbing resin particles, which comprises: preparing a hydrogel polymer by reversed-phase suspension polymerization of a water-soluble ethylenically unsaturated monomer in a hydrocarbon solvent in the absence of an internal crosslinking agent but in the presence of a

1. A method for producing water-absorbing resin particles, which comprises: preparing a hydrogel polymer by reversed-phase suspension polymerization of a water-soluble ethylenically unsaturated monomer in a hydrocarbon solvent in the absence of an internal crosslinking agent but in the presence of a surfactant having an HLB in a range from 8 to 12; andcarrying out a post-crosslinking reaction of the hydrogel polymer, whose moisture content has been adjusted so as to form a first-dried gel, to in a range from 30 to 110 mass % relative to a water-soluble ethylenically unsaturated monomer component that forms the hydrogel polymer,wherein a ratio (A:B) is in a range from 99:1 to 70:30, where A is a moisture content (A) of the first-dried gel and B is a moisture amount (B) added with a post-crosslinking agent for the post-crosslinking reaction. 2. The method according to claim 1, wherein the surfactant having the HLB in a range from 8 to 12 is at least one compound selected from the group consisting of sorbitan fatty acid esters, polyglycerine fatty acid esters, and sucrose fatty acid esters. 3. The method according to claim 1, wherein the post-crosslinking agent is a glycidyl ether compound. 4. The method according to claim 1, wherein an amount of the post-crosslinking agent is in a range from 0.0001 to 1 mol % relative to a total molar amount of the water-soluble ethylenically unsaturated monomer. 5. The method according to claim 1, wherein an amount of the post-crosslinking agent relative to a total molar amount of the water-soluble ethylenically unsaturated monomer is in a range satisfying formula (1): (−0.0002Z+0.023)≦Y≦(−0.0002Z+0.050)  (1)wherein Y represents an amount (mol %) of the post-crosslinking agent, andZ represents the moisture content (mass %) of the hydrogel polymer upon mixing with the post-crosslinking agent. 6. Water-absorbing resin particles obtained by the method according to claim 1. 7. The water-absorbing resin particles according to claim 6, wherein equilibrium swelling capacity of the water-absorbing resin is in a range from 10 to 28 mm,a water-absorption rate of the water-absorbing resin is in a range from 1 to 20 seconds, anda median particle size of the water-absorbing resin is in a range from 80 to 400 μm. 8. An absorbent article, which comprises: a liquid-permeable sheet;a liquid-impermeable sheet; andan absorber sandwiched between the liquid-permeable sheet and the liquid-impermeable sheet, the absorber including the water-absorbing resin particles according to claim 6. 9. A water blocking material, which comprises: two or more liquid-permeable sheets; andan absorber sandwiched with the two or more liquid-permeable sheets, the absorber including the water-absorbing resin particles according to claim 6 in an amount from 30 to 300 g/m2.