Patent ID: 8563660

Claim:
A fluororubber-based sealing material obtained by crosslinking a composition for a fluororubber-based sealing material, said composition comprising: a fluorine-containing copolymer containing 64 to 69% by weight of fluorine, having a crosslinking site derived from a bromine-containing compound and/or an iodine-containing compound and capable of being crosslinked by a peroxide, an organic peroxide in an amount of 0.5 to 6 parts by weight based on 100 parts by weight of the fluorine-containing copolymer, and a polyfunctional monomer in an amount of 1 to 10 parts by weight based on 100 parts by weight of the fluorine-containing copolymer, wherein the fluorine-containing copolymer in the composition for a fluororubber-based sealing material is a fluororubber polymer obtained by copolymerizing the following components (a) to (e): (a) vinylidene fluoride (VDF) in an amount of 30 to 70% by mol, (b) tetrafluoroethylene (TFE) in an amount of 12 to 30% by mol, (c) perfluoro(methyl vinyl ether) (FMVE) in an amount of 10 to 20% by mol, (d) perfluoro(methoxymethyl vinyl ether) (FMMVE) in an amount of 5 to 30% by mol, and (e) brominated and/or iodinated unsaturated fluorohydrocarbon in amount of 0.01 to 3% by mol based on 100% by mol of the total amount ((a)+(b)+(c)+(d)) of the component (a) to the component (d).