PURPOSE: To obtain a recyclable chlorinated polyolefinic rubber composition having excellent mechanical strengths, flexibility and calendering and proper magnetic properties, by blending a chlorinated polyolefin with specific magnetic powder and an epoxy compound.

CONSTITUTION: This composition comprises (A) 100 pts.wt. of a chlorinated polyolefin (preferably a chlorinated polyethylene or a chlorinated ethylene- propylene copolymer), (B) 100-600 pts.wt. of a mercapto-based silane coupling agent (e.g. γ-mercaptopropyltrimethoxysilane), (C) 1-10 pts.wt. of an epoxy compound (preferably an epoxidized vegetable oil) and (D) 0.1-10 pts.wt. of a high molecular-weight hindered phenol compound (preferably a bis[2-methyl-4-{3-n- alkylthiopropionyloxy}-5-t-butylphenyl] sulfide) wherein an n-alkyl is 12-14C.