Patent ID: 8202933

Claim:
A silicone resin composition for encapsulating light-emitting elements consisting essentially of: (A) a liquid or solid organopolysiloxane having at least two alkenyl groups per molecule represented by Average Compositional Formula (1): R n SiO (4-n)/2 (1) wherein each R is independently a substituted or unsubstituted monovalent hydrocarbon, alkoxy, or hydroxy group; 0.1 to 80 mol % of R which is a substituted or unsubstituted monovalent hydrocarbon comprises alkenyl groups; and n is a positive number that satisfies 1≦n<2; (B) an organohydrogenpolysiloxane having at least two Si—H bonds per molecule represented by Average Compositional Formula (2): R′ a H b SiO (4-a-b)/2 (2) wherein each R′ is independently a substituted or unsubstituted monovalent hydrocarbon excluding an aliphatic unsaturated hydrocarbon; and a and b are each positive numbers that satisfy 0.7≦a≦2.1, 0.001≦b≦1.0, and 0.8≦a+b≦2.6; and/or an organohydrogensilane represented by Formula (3): R′ c SiH (4-c) (3) wherein each R′ is as defined above, and c is 1 or 2; and (C) an addition reaction catalyst; the composition further comprising (D) 2 to 25 wt % of silica with a mean particle size of 1 to 30 nm based on the total amount of Components (A) and (B); the composition having a viscosity (23° C.) of more than 10 Pa·s and less than 70 Pa·s, and having a thixotropic index of 2.0 to 5.5; and the composition being used for encapsulation using a potting method.