PURPOSE: To improve vulcanization rate and mechanical strength, by blending sulfur, a guanidine vulcanization accelerator and a specified thiuram compd. with a blend of a halogenated EPDM and a diene rubber.
CONSTITUTION: Sulfur as a crosslinking agent, a guanidine vulcanization accelerator and compds. of formulas I and/or II (wherein R1, R2 are each a 1W20C alkylene; R3, R4, R5, R6 are each H, a 1W20C alkyl; X is 3W8) as vulcanization accelerators are blended with a rubber component consisting of 5W95wt% halogenated ethylene/α-olefin/non-conjugated diene copolymer rubber (halogenated EPDM) having a halogen content of 0.2W10wt% and 95W5wt% diene rubber. Examples of the compds. of formulas I and II are tetramethyl thiuram tetrasulfide and dipentamethylene thiuram hexasulfide.
SHIMADA NOBORU
MATSUMURA YOSHIO
