Patent ID: 8173736

Claim:
A method of injection molding a silicone rubber composition, comprising: filling a mold by injection of at least one addition curable liquid silicone rubber composition into said mold, said composition comprising: (A) 100 parts by mass of an organopolysiloxane containing at least two alkenyl groups bonded to silicon atoms within each molecule and having a viscosity at 25° C. within a range of 0.1 to 100 Pa·s, (B) an organohydrogenpolysiloxane containing at least two hydrogen atoms bonded to silicon atoms within each molecule and having a viscosity at 25° C. within a range from 0.0001 to 5 Pa·s, in sufficient quantity to provide from 0.4 to 5.0 hydrogen atoms bonded to silicon atoms within said component (B) for each alkenyl group bonded to a silicon atom within said component (A), (C) from 10 to 40 parts by mass of at least one fumed silica with a specific surface area measured by a BET method of 50 m 2 /g or greater, (D) an effective quantity of at least one addition reaction catalyst, and (E) from 0.1 to 10 parts by mass of a straight-chain diorganopolysiloxane containing at least one hydroxyl group bonded to a silicon atom within each molecule, with a viscosity at 25° C. within a range from 0.001 to 3 Pa·s, and a hydroxyl number within a range from 1.0×10 −2 to 0.5×10 −2 mol/g, and exhibiting fluidity such that, at 23° C., a viscosity at a shear velocity of 0.9 s −1 is not higher than 1,000 Pa·s, and a ratio between a viscosity at a shear velocity of 100 s −1 and a viscosity at a shear velocity of 200 s −1 is not higher than 3.5; and curing said composition present in said mold, wherein a number of hydroxyl groups within a hydroxyl group-containing straight-chain diorganopolysiloxane of said component (E), relative to a total surface area of said fumed silica of said component (C), is within a range from 1.5×10 −8 to 2.0×10 −6 mol/m 2 .