ETHYLENE-PROPYLENE-DIENE RUBBER, ELASTOMER COMPOSITION AND VULCANIZED RUBBER THEREOF

摘要

The present invention provides ethylene-propylene-dienerubbers which are excellent in co-vulcanizability withconjugated diene rubbers and can impart excellent weatherresistance, ozone resistance and thermal aging resistancewithout detriment to excellent mechanical characteristics,wear resistance and dynamic fatigue resistance which theconjugated diene rubbers possess.The ethylene-propylene-diene rubbers of the presentinvention are characterized by having a Mooney viscosity ML1+4(100°C) of 50 to 120 and comprising(A) 90 to 40% by weight of a high-molecular weightethylene-propylene-diene copolymer rubber having an ethylenecontent of 73 to 85 mol%, an intrinsic viscosity [.pi.] of 2.5to 5.0 dl/g as measured at 135°C in decalin and an iodinevalue of 15 to 35, and(B) 10 to 60% by weight of a low-molecular-weightethylene-propylene-diene copolymer rubber having an ethylenecontent of 73 to 85 mol%, an intrinsic viscosity [.pi.] of 0.15to 0.8 dl/g as measured at 135°C in decalin and an iodinevalue of l5 to 35.Further, the present invention provides elastomercompositions comprising the ethylene-propylene-diene rubberas mentioned above, a conjugated diene rubber and aninorganic filler, and vulcanized rubbers obtained by co-vulcanizing said compositions.The vulcanized rubbers are very useful for tires,automobile parts, general-purpose industrial components andcivil engineering and building components, particularlymaterials which require dynamic fatigue resistance.