A thermoplastic elastomer with well-balanced physical properties is prepared by treating a rubber/resin composition comprised of (a) 45 - 90 wt. parts of a rubbery component and (b) l0 - 55 wt. parts of a polyolefin resin, with a curing agent. The rubbery component (a) is comprised of 5 - l00 wt.% of an ethylene-propylene copolymer rubber having an ethylene content of 60 - 78 mole%, a crystallinity of 4 to 20%, a maximum peak temperature of melting of at least l00°C, an MFI of less than 0.01 at 230°C, an HLMFI/MFI of at least 35, an Mw/Mn of at least 4, and a tensile strength at break of at least l00 kg/cm², and 95 - 0% by weight of an ethylene-propylene-nonconjugated diene copolymer. The rubbery component in the cured product has a gel content more than 80 wt.% and less than 97 wt.% as determined by immersion in cyclohexane at 23°C for 48 hours.
通过用固化剂处理由(a) 45 - 90 重量份的橡胶成分和(b) l0 - 55 重量份的聚烯烃
树脂组成的橡胶/
树脂组合物,制备具有良好平衡物理性能的热塑性弹性体。橡胶组分 (a) 由 5 - l00 重量份的
乙烯-
丙烯共聚橡胶组成,
乙烯含量为 60 - 78 摩尔%,结晶度为 4 - 20%,熔融最高温度至少为 l00°C,在 230°C 时 MFI 小于 0.01,HLMFI/MFI 至少为 35,Mw/Mn 至少为 4,断裂拉伸强度至少为 l00 kg/cm²,
乙烯-
丙烯-非共轭二烯共聚物的重量百分比为 95 - 0%。根据在 23°C
环己烷中浸泡 48 小时的测定,固化产品中橡胶成分的凝胶含量大于 80%,小于 97%。