| 摘要 |
PROBLEM TO BE SOLVED: To obtain a rubber compsn. excellent in compression set properties by compounding a vulcanizing agent or a crosslinker into an ethylene copolymer rubber having a specified ethylene/6-12Cα-olefin ratio, iodine value, Mooney viscosity, wt. average mol.wt./number average mol.wt. ratio, glass transition temp., and branch index B. SOLUTION: This compsn. is prepd. by compounding 100 pts.wt. ethylene copolymer rubber comprising ethylene units, 6-12Cα-olefin units, and nonconjuated polyene units of the formula with 0.1-10 pts.wt. vulcanizing agent (e.g. powdered sulfur) or 0.1-15 pts.wt. crosslinker (e.g. dicucmyl peroxide) and other necessary additives. The copolymer rubber used has an ethylene/6-12Cα-olefn molar ratio of (40/60)-(70/30), an iodine value of 15-45, a Mooney viscosity of 40-150, a wt. average mol.wt./number average mol.wt. ratio of 2.5-15, a glass transition temp. of -80 to -50 deg.C, and a branch index B of 0.60-0.95. In the formula, X is a 1-20C hydrocarbon group; R<1> and R<2> are each H or 1-8C alkyl; and R<3> is 1-8C alkyl.
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