ETHYLENE-ALPHA-OLEFIN-POLYENE RANDOM COPOLYMER RUBBER

摘要

An ethylene-alpha-olefin-polyene random copolymer rubber comprising ethylene, an alpha-olefin having 3 to 10 carbon atoms and a polyene, wherein (A) a molar ratio of ethylene/alpha-olefin is 55/45 to 95/5, (B) the polyene is a mixture of 5-ethylidene-2-norbornene (ENB) and 5-vinyl-2-norbornene (VNB) in a molar ratio of ENB/VNB of 1/1 to 20/1, (C) an iodine value of the copolymer rubber is 2 to 40, (D) an intrinsic viscosity [ eta ] of the copolymer rubber is 1.0 to 6.0 dl/g measured in decalin at 135 DEG C., and (E) g eta * defined by a ratio of the intrinsic viscosity [ eta ] to an intrinsic viscosity [ eta ]l of a linear ethylene-propylene random copolymer having an ethylene content of 70 mole % and the same weight-average molecular weight determined by a light-scattering method as that of the copolymer rubber is 0.2 to 0.9. Also a process for preparing this random copolymer rubber and vulcanizate derived from the same are also disclosed. This random copolymer rubber has an excellent extrudability and a fast cure rate and provides a vulcanizate having high tensile strength.