PROCESS FOR PRODUCTION OF WATER-ABSORBABLE RESIN

摘要

The present application provides a process for producing a water-absorbable resin and a water-absorbable resin produced by the process, more specifically a process for producing a water-absorbable resin by a reversed-phase suspension polymerization method wherein the odor originated from a raw material component, particularly a petroleum hydrocarbon dispersion medium, in the water-absorbable resin can be further reduced compared with the odors in water-absorbable resins produced by conventional techniques and a water-absorbable resin produced by the process. More specifically, the present application provides: a process for producing a water-absorbable resin by the reversed-phase suspension polymerization of a water-soluble ethylenically unsaturated monomer in a petroleum hydrocarbon dispersion medium, which is characterized by comprising the steps of (A) adding an aqueous water-soluble ethylenically unsaturated monomer solution containing a hydrophilic polymer dispersant to a petroleum hydrocarbon dispersion medium having a hydrophobic polymer dispersant thermally dispersed or dissolved therein while agitating the mixed solution to cause primary dispersion in the absence of any surfactant, (B) adding a surfactant to a dispersion obtained after the primary dispersion to cause secondary dispersion, and (C) carrying out reversed-phase suspension polymerization using a radical polymerization initiator; and a water-absorbable resin produced by the process.