Addition curable liquid silicone rubber composition for injection molding, method of regulating fluidity of the composition, and method of injection molding silicone rubber composition

摘要

An addition curable liquid silicone rubber composition for injection molding is provided. The composition comprises (A) an organopolysiloxane containing at least two Si-bonded alkenyl groups within each molecule, (B) an organohydrogenpolysiloxane containing at least two Si-bonded hydrogen atoms within each molecule, (C) a fumed silica with a BET specific surface area of 50 m²/g or greater, and (D) an addition reaction catalyst, and exhibiting fluidity such that, at 23°C, the viscosity at a shear velocity of 0.9 s^-1 is not higher than 1,000 Pa·s, and the ratio between the viscosity at a shear velocity of 100 s^-1 and the viscosity at a shear velocity of 200 s^-1 is not higher than 3.5. The composition is resistant to decreases in viscosity of the rubber material under high shear velocity, and generates no burrs on the molded product.