Nok Corporation

Chiyota Ogata

Masashi Kudo

Masaya Otsuka

Takashi Amemiya

Tatsuo Okamura

A fluororubber sealant composition includes 100 parts by weight of a fluororubber, which is a copolymer having a cross-linking site derived from a bromine-containing and/or iodine-containing compound, capable of crosslinking with peroxide and having a component unit composition comprising 20 to 23% by mol of a perfluoromethyl vinylether component unit, 60 to 70% by mol of a vinylidene fluoride component unit, 10 to 20% by mol of a tetrafluoroethylene component unit, 0 to 10% by mol of hexafluoropropylene component unit (based on 100% of the total of the above component units), and a small amount of a bromide and/or iodide unsaturated fluorohydrocarbon component unit as a crosslinking site based on 100% by mol of the total of the above component units; and further comprising, based on 100 parts by weight of the fluororubber, 2 to 50 parts by weight of a bituminous fine powder; 0.5 to 6 parts by weight of an organoperoxide; and 1 to 10 parts by weight of a polyfunctional monomer. A sealant is prepared by vulcanizing the above composition. The composition has not only excellent ordinary physical properties but also excellent heat resistance, freeze resistance and fuel oil resistance so that it is suitably used as sealants for automobile fuel.

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Aso-gun, Japan

Chiyota Ogata