PROCESS FOR PRODUCTION OF WATER-ABSORBENT RESIN

摘要

The present invention is directed to an improved process for the production of a water-absorbent resin by reversed phase suspension polymerization of a water-soluble ethylenic unsaturated monomer. The process is conducted by subjecting an aqueous solution of a water-soluble ethylenic unsaturated monomer to a reversed phase suspension polymerization reaction in a first stage. The polymerization is conducted in a petroleum hydrocarbon solvent in the presence of a surfactant and/or polymeric protective colloid using a radical polymerization initiator optionally in the presence of a crosslinking agent, cooling the resulting slurry to precipitate the surfactant and/or polymeric protective colloid, and then repeating the polymerization by adding an aqueous solution of a water-soluble ethylenic unsaturated monomer containing a radical polymerization initiator and optionally a crosslinking agent to the first polymerization reaction system to further carry out the reversed phase suspension polymerization reaction, at least, once.