HIGHLY SATURATED NITRILE COPOLYMER RUBBER, PROCESS FOR THE PRODUCTION THEREOF, HEAT-RESISTANT RUBBER COMPOSITIONS COMPRISING THE RUBBER AND COMPOSITES COMPRISING THE RUBBER AND FIBERS

摘要

A highly saturated nitrile group-containing copolymer rubber having a Mooney viscosity lowered by 15 points or more by applying a high shearing force thereto in the presence of an aging inhibitor, which has a Mooney viscosity of 5 - 35 and a weight average molecular weight/number average molecular weight ratio of 3 - 5, and exhibits an increase in Mooney viscosity of 10 points or fewer while the rubber is allowed to stand in the air at room temperature for 30 days. The viscosity of the copolymer rubber changes only to a minor extent with the lapse of time, and the copolymer rubber has excellent processability and storage stability. The copolymer rubber can be used as a heat-resistant rubber composition comprising the copolymer rubber and other heat-resistant rubber. The copolymer rubber can be used as a composite thereof with a fiber, which has good mechanical strength.