Patent ID: 9068053
Filing Date: 2015-06-30
Classification: B29D,C08K,C08L

Abstract:
1. A fluoro rubber composition comprising a rubber component comprising: a fluoro rubber; carbon black; and a vulcanization system compounding agent containing a co-crosslinking agent, wherein the fluoro rubber is at least one member selected among (A) a copolymer of tetrafluoroethylene/perfluoroalkyl vinyl ether, (B) a copolymer of tetrafluoroethylene/propylene, and (C) a copolymer made of (i) at least one monomer selected among tetrafluoroethylene, hexafluoropropylene, pentafluoropropylene, trifluoroethylene, chlorotrifluoroethylene, vinyl fluoride, perfluoroalkyl vinyl ether and propylene, and (ii) vinylidene fluoride; in a kneading step of compounding the carbon black in the rubber component, an average shear rate of a rotor tip point of a kneading machine is 100 (1/sec) or more, and a kneading maximum temperature T in a dynamic viscoelasticity test of an unvulcanized rubber by a rubber process analyzer (RPA) (measurement temperature: 100° C., measurement frequency: 1 Hz), a difference δG wherein the elongation at break at 25° C. of the fluoro rubber composition after vulcanization is 400% or more and not more than 800%, and wherein a compounding amount of the co-crosslinking agent is 0.5 to 2.5 parts by mass based on 100 parts by mass of the rubber component.