Patent ID: 9499678
Filing Date: 2016-11-22
CPC Classification: C08K

Claim Text:
1. A fluororubber composition comprising: a fluororubber (A); and a carbon black (B), the fluororubber (A) being a vinylidene fluoride-based fluororubber comprising a structural unit derived from vinylidene fluoride (VdF unit) and a structural unit derived from 2,3,3,3-tetrafluoro propylene, the molar ratio of the VdF unit to the structural unit derived from 2,3,3,3-tetrafluoro propylene being 50/50 to 78/22, wherein the fluororubber composition has a difference δG′ (G′ (1%)-G′ (100%)) of not lower than 120 kPa and not higher than 3,000 kPa, where G′ (1%) denotes a modulus of shearing elasticity at a dynamic strain of 1%, G′ (100%) denotes a modulus of shearing elasticity at a dynamic strain of 100%, and G′ (1%) and G′ (100%) are determined by a dynamic viscoelasticity test carried out on an unvulcanised rubber with a rubber process analyzer (RPA) in a condition that the measurement frequency is 1 Hz and the measurement temperature is 100° C., and the Mooney viscosity at 100° C. of the fluororubber (A) is 43 to 200.