| 摘要 |
The invention provides ethylene-propylene-diene rubbers capable of imparting excellent heat resistance, weather resistance and dynamic fatigue resistance to vulcanized rubbers made therefrom. The ethylene-propylene-diene rubbers have sulfur dispersed therein at a temperature of 90 DEG to 160 DEG C. prior to the addition of vulcanization accelerators or other rubber additives. The ethylene-propylene-diene rubbers contain (A) 90 to 40% by weight of a high-molecular weight ethylene-propylene-diene copolymer rubber having an ethylene content of 60 to 82 mol %, an intrinsic viscosity ( eta ) of 3.0 to 5.0 dl/g as measured at 135 DEG C. in decalin and an iodine value of 8 to 35, (B) 10 to 60% by weight of a low-molecular-weight ethylene-propylene-diene copolymer rubber having an ethylene content of 60 to 82 mol %, an intrinsic viscosity ( eta ) of 0.15 to 0.8 dl/g as measured at 135 DEG C. in decalin and an iodine value of 8 to 35, and (C) sulfur in an amount of 0.1 to 5 parts by weight based on 100 parts by weight of the rubber dispersed therein at a temperature of 90 DEG to 160 DEG C. prior to the addition of a vulcanization accelerator or other rubber additive. The vulcanized rubbers are particularly suitable for use as automobile components which require dynamic fatigue resistance such as muffler hangers, belts, rubber vibration insulators, engine mounts, tire treads for pneumatic tires, sidewalls for pneumatic tires and white sidewalls.
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