Abstract: The present fluorosilicone rubber composition cures to give fluorosilicone rubber moldings with excellent physical properties. The fluorosilicone rubber composition comprises:(A) a 3,3,3-trifluoropropylmethylsiloxane-methylvinylsiloxane copolymer gum,(B) a dimethylsiloxane-methylvinylsiloxane copolymer gum,(C) a poly(3,3,3-trifluoropropylmethylsiloxane)-polydimethylsiloxane block copolymer or (C-2) a poly(3,3,3-trifluoropropylmethylsiloxane)-polydimethylsiloxane-polymethylv inylsiloxane block copolymer,(D) a reinforcing silica micropowder that has a surface area of at least 50 m.sup.2 /g, and(E) a curing agent.

Abstract: The composition of the present invention comprises a oil-resistant silicone rubber composition that undergoes little swelling even when used in regular or continuous contact with mineral oil-based lubricating oil such as engine oil and so forth. The oil-resistant silicone rubber composition comprises:(A) a dimethylsiloxane-3,3,3-trifluoropropylmethylsiloxane-methylvinylsiloxane copolymer gum that contains 0.001 to 5 mole percent methylvinylsiloxane unit,(B) a hydrocarbon oil or diorganopolysiloxane oil wherein the total in each diorganopolysiloxane oil molecule of the number of silicon-bonded hydrogen atoms and the number of functional groups reactive with component (A) or (C) is less than two,(C) a reinforcing filler, and(D) a curing agent in a quantity sufficient to cure the composition.