| 摘要 |
PROBLEM TO BE SOLVED: To obtain a rubber compsn. for packing which does not exhibit the degradation in physical properties, does not adhere to copper or a copper alloy, and does not cause the formation of green rust by compounding an ethylene-α- olefin-nonconjugated diene copolymer rubber with a carbon black, an antioxidant comprising a trimethyldihydroquinone polymer and 2-mercaptobenzimidazole, and an org. peroxide. SOLUTION: The copolymer pref. contains 45-50mol% propylene units as theα-olefin units. A pref. example of the nonconjugated diene is 5-ethylidene-2- norbornene. The antioxidant comprises a 2,2,4-trimethyl-1,2-dihydroquinone polymer and 2-mercaptobenzimidazole in a wt. ratio of (1/1)-(2/0.5) and is compounded in an amt. of 1-5wt.% of the rubber. This compsn. is vulcanized with an org. peroxide. A lubricant (e.g. laurylamide or stearylamide) is compounded in an amt. of 5wt.% or lower of the rubber to increase the compression set and to prevent the formation of green rust.
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