A rubber composition excellent in shape-retainability also in processibility, compression set and the like, which comprises a single ethylene-α-olefin-non-conjugated diene copolymer which has (1) a Mooney viscosity (ML1+4, 100°C) of 80 to 200, (2) a weight average molecular weight/number average molecular weight ratio of 6 or more as measured by a gel permeation chromatography (GPC), and (3) a stress-retention of 0.2 or more after 100 seconds at 80°C in a compression type stress-relaxation test.
一种橡胶组合物,在保形性、加工性、压缩永久变形等方面也非常出色,它由单一
乙烯-α-烯烃-非共轭二烯共聚物组成,该共聚物具有 (1) 80 至 200 的门尼粘度(ML1+4,100°C),(2) 经凝胶渗透色谱法(
GPC)测定的重量平均分子量/数量平均分子量比为 6 或以上,以及 (3) 在 80°C 的压缩型应力松弛试验中,100 秒后的应力保持率为 0.2 或以上。2 或以上。