Patent ID: 7005466

Claim:
A silicone rubber composition comprising the following components: (A) 100 parts by weight of a polyorganosiloxane gum, (B) 25 to 100 parts by weight of a finely divided, reinforcing silica filler, (C) 0.005 to 5.00 parts by weight of acid selected from the group consisting of (i) orthoboric acid and and (ii) metaboric acid, (D) 5 to 100 parts by weight of a powdered calcium carbonate, (E) an organic peroxide curing agent in an amount to be sufficient to effect curing of the composition, and an additive for improving water-repellent properties comprising a material selected from the group consisting of (F) a polyorganosiloxane having a viscosity of 1 to 10,000 mPa·s and containing in one molecule at least two silicon-bonded hydrogen atoms; and (G) a mixture of Component (F) with a polydiorganosiloxane having a viscosity of 1 to 10,000 mPa·s; in an amount of 0.1 to 20 parts by weight based on 100 parts by weight of said Component (A).