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Abstract

The present invention provides ethylene-propylene-diene rubbers which are excellent in co-vulcanizability with conjugated diene rubbers and can impart excellent weather resistance, ozone resistance and thermal aging resistance without detriment to excellent mechanical characteristics, wear resistance and dynamic fatigue resistance which the conjugated diene rubbers possess. The ethylene-propylene-diene rubbers of the present invention are characterized by having a Mooney viscosity ML.sub.1+4 (100.degree. C.) of 50 to 120 and comprising (A) 90 to 40% by weight of a high-molecular weight ethylene-propylene-diene copolymer rubber having an ethylene content of 73 to 85 mol %, an intrinsic viscosity [.eta.] of 2.5 to 5.0 dl/g as measured at 135.degree. C. in decalin and an iodine value of 15 to 35, and (B) 10 to 60% by weight of a low-molecular-weight ethylene-propylene-diene copolymer rubber having an ethylene content of 73 to 85 mol %, an intrinsic viscosity [.eta.] of 0.15 to 0.8 dl/g as measured at 135.degree. C. in decalin and an iodine value of 15 to 35. Further, the present invention provides elastomer compositions comprising the ethylene-propylene-diene rubber as mentioned above, a conjugated diene rubber and an inorganic filler, and vulcanized rubbers obtained by co-vulcanizing said compositions. The vulcanized rubbers are very useful for tires, automobile parts, general-purpose industrial components and civil engineering and building components, particularly materials which require dynamic fatigue resistance.

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First Claim