WATER-SWELLING RESIN COMPOSITE AND ITS PRODUCTION

摘要

PROBLEM TO BE SOLVED: To simply and easily obtain a water-swelling resin composite which exhibits stable swelling performance over a long period of time by curing and vulcanizing a kneaded material comprising an unvulcanized rubber and a water- swelling polyoxyethylene-base polyurethane resin having a specified composition. SOLUTION: A partially blocked prepolymer having terminal isocyanate groups and obtained from a polyoxyalkylene polyol having at least 30wt.% oxyethylene units and an organic polyisocyanate (e.g. 2,4-tolylene diisocyanate) is reacted with an active hydrogen compound (e.g. ethylene glycol) to produce a water-swelling polyoxyethylene-base polyurethane resin having both blocked isocyanate groups and groups containing an active hydrogen atom. This resin is kneaded together with an unvulcanized rubber, and the kneaded material is heated at the vulcanization temperature of the rubber to vulcanize the rubber and cure the resin, thus giving a water-swelling resin composite. This composite is useful for, e.g. a gasket for a building.