| abstract |
A novel rubbery copolymer comprising (A) 5 to 95% by weight of structural units based on 1,1-dicyano-2-vinylcyclopropane and (B) 95 to 5% by weight of structural units based on a 1,1-difluoro-2-vinylcyclopropane and having a weight average molecular weight, calculated for standard polystyrene, of 2,000 to 2,000,000 is provided by copolymerizing the 1,1-dicyano-2-vinylcyclopropane and the 1,1-difluoro-2-vinylcyclopropanes in the presence of a free radical initiator. This rubbery copolymer and its hydrogenated product give a vulcanizate having improved oil resistance, cold resistance, thermal resistance, sour gasoline resistance, alcohol-containing gasoline resistance and alcohol-containing sour gasoline resistance. |