PURPOSE: To obtain a new inexpensive material having the properties of rubber and a synthetic resin, by incorporating a kneaded mixture of the rubber with the synthetic resin in equal amounts with a polyfunctional unsaturated ester, a crosslinking agent, etc., and molding and crosslinking the mixture under heating.

CONSTITUTION: (A) Masticated raw rubber or a reclaimed rubber, preferably 100pts.wt. high-styrene rubber, is kneaded with (B) an equal amount of a (regenerated) synthetic resin, preferably polyethylene, and the resultant mixture is then kneaded with (C) a polyfunctional unsaturated ester, preferably 10pts.wt. acrylic ester and 10pts.wt. diallyl phthalate, (D) a crosslinking agent, preferably 3pts.wt. Percadox, and (E) a reinforcing agent, preferably 100pts.wt. carbon, or further (F) other additives, e.g. 20pts.wt. calcium carbonate, 5pts.wt. zinc flower, 1pt.wt. stearic acid and 1pts.wt. sulfur, and heated to the softening temperature of the component (A), e.g. 90°C, then molded under heating to crosslink the component (C).