| 摘要 |
PROBLEM TO BE SOLVED: To obtain excellent wear resistance by using as the constituents of a rubber composition an ethylene/3-20Cα-olefin/nonconjugated diene copolymer rubber, an organic peroxide, carbon black and a softener each in a specified amount. SOLUTION: This composition contains 100 pts.wt. ethylene/3-20Cα-olefin/ nonconjugated polyene copolymer rubber having diene units derived from a nonconjugated diene represented by formula I or formula II, 0.5-15 pts.wt. organic peroxide, 30-80 pts.wt. carbon black and 5-25 pts.wt. softener. The copolymer rubber has a nonconjugated polyene content of 0.2-4 wt.% and an intrinsic viscosity (in decalin) of 1.5-3 dl/g. In the copolymer, the molar ratio of ethylene toα-olefin is (50:50) to (72:28) when theα-olefin comprises a 3-20Cα-olefin, particularly propylene, and (60:40) to (82:18) when theα-olefin comprises a 4-20Cα-olefin. In the formulas, R<1> and R<3> are each H or a 1-10C alkyl; and R<2> is H or a 1-5C alkyl.
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