A
fluorine-containing
elastomer for molding fuel
system parts, which has a
copolymer composition comprising 10-40% by weight of
tetrafluoroethylene (TFE), 80-30% by mole of vinylidene
fluoride (VdF), and 10-30% by mole of
hexafluoropropylene (HFP), as copolymerized in the presence of an
iodine and
bromine-containing compound represented by the following general formula: RBrnIm (where R is a
fluorohydrocarbon group, a chlorofluorohydrocarbon group, or a
hydrocarbon group, each having 1-10 carbon atoms, and n and m each are 1 or 2), and has an
intrinsic viscosity of 20-180 ml / g, Mw (weight average molecular weight) / Mn (number average molecular weight) ratio of 2-20, and a molecular
weight distribution of monopeak or multipeak type, and a
fluorine-containing
elastomer composition, which comprises the
fluorine-containing
elastomer, at least one of a
polyol vulcanizing agent and a
polyamine vulcanizing agent, an
organic peroxide, and a polyfunctional unsaturated compound. The composition is suitable for use in molding fuel
system parts to give fluorine-containing elastomer moldings with distinguished moldability, vulcanizate physical properties,
chemical resistance, photostability and economy.