Patent ID: 8618234

Claim:
A silicone-based pressure-sensitive adhesive composition comprising: 100 parts by weight of (A) a branched organopolysiloxane having on average at least two alkenyl groups on molecular terminals and represented by the following molecular formula (1): (R 3 SiO 1/2 ) 4-p (R 1 R 2 SiO 1/2 ) p (R 2 SiO) m (RR 1 SiO) n (SiO 4/2 )â€ƒâ€ƒ(1) (wherein R designates a monovalent hydrocarbon group or a monovalent halogenated hydrocarbon group which is free of unsaturated aliphatic bonds and has 1 to 10 carbon atoms; R 1 designates an alkenyl group having 2 to 10 carbon atoms; â€œpâ€ is a number which on average is in the range of 2 to 4; â€œmâ€ is a number which on average is in the range of 1,500 to 10,000; â€œnâ€ is a number which on average is equal to or greater than 0; and m>n, and (m+n) on average is in the range of 1,500 to 10,000); 10 to 400 parts by weight of (B) an organopolysiloxane resin composed of R 3 R 2 2 SiO 1/2 units (where R 2 designates an alkyl group with 1 to 10 carbon atoms, R 3 designates an alkyl group with 1 to 10 carbon atoms, an alkenyl group with 2 to 10 carbon atoms, an aryl group with 6 to 10 carbon atoms or a hydroxyl group) and SiO 4/2 units, where the mole ratio of the R 3 R 2 2 SiO 1/2 units to SiO 4/2 units ranges from 0.6 to 1.7; (C) an organohydrogenpolysiloxane having in one molecule two or more silicon-bonded hydrogen atoms, which is used in an amount sufficient to provide a mole ratio of silicon-bonded hydrogen atoms of this component to alkenyl groups contained in components (A) and (B) in the range of 1.0 to 60; and (D) a catalytic quantity of a platinum-type catalyst.