A process for preparing an ethylene/α-olefin/norbornene nonconjugated polyene random copolymer, comprising preparing an ethylene random copolymer simultaneously meeting the following requirements (1) to (5):
(1) the molar ratio of ethylene (a) to an α-olefin (b) having 3 to 20 carbon atoms ranges from 40:60 to 95:5;
(2) a given amount of non conjugated polyene (c) has a norbornene skeleton;
(3) the available network chain density ν is not less than 1.5 x 1020/cm3 after press cross-linking of the copolymer using a dicumyl peroxyde;
(4) the ratio of the rate γ1 of shear showing a shearing stress of 0.4 x 106 dyn/cm2 as determined from the melt flow curve at 100°C and the rate γ2 of shear showing a shearing stress of 2.4 x 106 dyn/cm2, that is γ2/γ1 and the available network chain density ν has a relationship represented by the following general formula: 0.04 x 10-19 ≤ Log(γ2/γ1)/ν ≤ 0.20 x 10-19; and
(5) the intrinsic viscosity [η] ranges from 0.5 to 10 dl/g as measured in decalin at 135°C. The copolymer has excellent cross-linkability, can be cross-linked with a small amount of a peroxide or the like, and a cross-linked rubber composition prepared using this copolymer has excellent heat aging resistance, mechanical strength, weather resistance, and oxone resistance.
一种制备
乙烯/α-烯烃/
降冰片烯非共轭聚烯无规共聚物的工艺,包括制备同时满足以下要求(1)至(5)的
乙烯无规共聚物:
(1)
乙烯(a)与具有 3 至 20 个碳原子的α-烯烃(b)的摩尔比为 40:60 至 95:5;
(2) 一定量的非共轭多烯(c)具有
降冰片烯骨架;
(3) 共聚物在使用
二异丙基过氧化物按压交联后,可用网络链密度 ν 不小于 1.5 x 1020/cm3
(4) 根据 100℃熔体流动曲线确定的剪切应力为 0.4×106 达因/厘米2 的剪切速率 γ1 与剪切应力为 2.4×106 达因/厘米2 的剪切速率 γ2,即 γ2/γ1,与可用网络链密度 ν 之比具有以下通式表示的关系:0.04 x 10-19 ≤ Log(γ2/γ1)/ν ≤ 0.20 x 10-19;以及
(5) 本征粘度[η]范围为 0.5 至 10 dl/g(在 135°C 的
癸醛中测量)。该共聚物具有优异的交联性,可与少量过氧化物或类似物交联,使用该共聚物制备的交联橡胶组合物具有优异的耐热老化性、机械强度、耐候性和耐氧化性。