To obtain a water-absorptive resin that has a high water absorption rate under normal and higher pressure, can be easily dried and ground at low load, and is useful for hygienic materials by copolymerizing specific compounds in aqueous solution in the presence of a fluorine-based surfactant.
This water-absorptive resin of a high water absorption rate is obtained by copolymerizing (B) aqueous solution of (i) a water-soluble unsaturated monomer, preferably (meth)acrylic acid or (meth)acrylate, 1-(meth) acryloylmethane sulfonic acid or sulfonate, etc., and (ii) a crosslinkable monomer, preferably a compound having two or more ethylenic unsaturated groups in one molecule, for example, ethylene glycol di(meth)acrylate, in the presence of (A) a fluorine-based surfactant (e.g. fluoroalkyl 2-10C carboxylic acids) in a quantity of 0.0001-10 pts.wt. based on 100 pts.wt. of component B, while bubbling the reaction solution with an inert gas introduced into the solution.
MIYAKE KOJI
MOTONO YOSHIHIRO
TAWARA HIDEYUKI
