| 摘要 |
ObjectThe main object of the present invention is to provide a method for producing water-absorbent resin having reduced5 discoloration resulting from high-temperature treatment, small amounts of fine powder and coarse powder, and a narrow particle size distribution.Means for achieving the object10 A method for producing water-absorbent resin,comprising:Step 1, in which a water-soluble ethylenically unsaturated monomer is subjected to a reversed-phase suspension polymerization in a petroleum hydrocarbon dispersion medium in15 which a surfactant is dissolved, thereby forming a slurry in which primary particles are dispersed, andStep 2, in which the slurry obtained in Step 1 is cooled to partially precipitate the surfactant, and then a(water-soluble ethylenically unsaturated monomer is polymerized20 in the slurry to agglomerate the primary particles, thereby forming water-absorbent resin,wherein the surfactant is a sucrose fatty acid ester in which the monoester content is 25% by mass or less, thetetraester content is 10% by mass or more, and the content of25 tetra or higher esters is 30% by mass or less.Selected figure: None |
