An ethylene-alpha-olefin-polyene random copolymer rubber comprising ethylene, an alpha-olefin having 3 to 10 carbon atoms and a ployene,wherein (A)a molar ratio of ethylene/al-p-ha-olefin is 55/45 to 95/5, (B) the polyene is a mixture of 5- ethyitdene-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 [η] of the copolymer rubber is 1.0 to 6.0 dl/g measured in decalin at 135°C, and (E) gη* defined by a ratio of the intrinsic viscosity [η] to an intrinsic viscosity [η]I 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.
一种
乙烯-α-烯烃-聚烯无规共聚橡胶,包括
乙烯、具有 3 至 10 个碳原子的α-烯烃和聚烯,其中 (A)
乙烯/α-烯烃的摩尔比为 55/45 至 95/5、(B) 聚烯是 5-乙基-2-
降冰片烯(ENB)和 5-
乙烯基-2-
降冰片烯(VNB)的混合物,ENB/VNB 的摩尔比为 1/1 至 20/1, (C) 共聚橡胶的
碘值为 2 至 40, (D) 共聚橡胶的固有粘度[η]为 1.0 至 6.0 dl/g;(E) 本征粘度[η]与线性
乙烯-
丙烯无规共聚物的本征粘度[η]I 之比定义的 gη* 为 0.2 至 0.9,线性
乙烯-
丙烯无规共聚物的
乙烯含量为 70 摩尔%,通过光散射法测定的重量平均分子量与共聚橡胶的重量平均分子量相同。此外,还公开了制备这种无规共聚物橡胶和由其衍生的
硫化胶的工艺。这种无规共聚物橡胶具有优异的挤出性和快速固化率,并可提供具有高拉伸强度的
硫化胶。