PRODUCTION OF HIGHLY WATER-ABSORPTIVE RESIN

PURPOSE:To obtain the title resin excellent in salt water absorptivity, by suspending an aqueous solution of a specified monomer mixture by dispersing in a hydrophilic solvent with the aid of a dispersant and polymerizing the monomers in the presence of a water-soluble radical initiator. CONSTITUTION:A mixture of an ethylenically unsaturated amine monomer (e.g., dimethylaminoethyl methacrylate) of formula I (wherein R1 is H or methyl, R2 is a 1-12C alkylene, R3-4 are each H or a 1-12C alkyl and A is a group of formula II or III or -O-) with an ethylenically unsaturated carboxylic acid monomer (e.g., acrylic acid) at a molar ratio of 10-90:90-10 is mixed with at least 30mol% other water-soluble monovinyl monomers (e.g., acrylamide) copolymerizable therewith and the resulting mixture is dissolved in water to obtain an aqueous monomer mixture solution. This aqueous solution is suspended by dispersing in a hydrophobic solvent (e.g., n-hexane) with the aid of a dispersant (e.g., sorbitan monostearate) and polymerized at 20-80 deg.C in the presence of 0.0005-1wt% water-soluble radical initiator.