FLUORORUBBER COMPOSITION AND PROCESS FOR PRODUCING CROSSLINKED FLUORORUBBER

摘要

A fluororubber composition which (1) has the excellent ability to absorb the shock of arm striking, (2) is nontacky, (3) is clean, and (4) contains no halogen (chlorine); and a process for producing a crosslinked fluororubber. The fluororubber composition is characterized by comprising a polyol-crosslinkable fluororubber constituted of a fluoropolymer, a polyol crosslinking agent, and a salt having BF4 - as the counter ion.  The composition is further characterized in that the polyol crosslinking agent is contained in an amount of 1.25-3.0 parts by weight in terms of active-ingredient amount per 100 parts by weight of the fluoropolymer and the salt having BF4 - as the counter ion is contained in an amount of 0.700-0.900 parts by weight per 100 parts by weight of the fluoropolymer.  The process for producing a crosslinked fluororubber is characterized by crosslinking the fluororubber composition with the polyol beforehand and then heat-treating the crosslinked composition in the temperature range of 200-300ºC for 0.1-48 hours to obtain the crosslinked fluororubber having a percentage increase in holding torque of 30% or less on the average.