Patent ID: 8772812
Filing Date: 2014-07-08
Classification: C08G,C08L,H01L

Abstract:
1. A curable organopolysiloxane composition comprising at least the following components: (A) an alkenyl-containing organopolysiloxane that comprises 15 to 35 wt. % of constituent (A-1) and 65 to 85 wt. % of constituent (A-2), wherein constituent (A-1) comprises an organopolysiloxane of the following average compositional formula: where R 1 designates phenyl groups, methyl groups, or alkenyl groups having 2 to 10 carbon atoms; 0.4 to 50 mole % of all R 1 groups are alkenyl groups having 2 to 10 carbon atoms; methyl groups constitute 90 mole % or more of the sum of methyl and phenyl groups contained in R 1 ; “a”, “b”, “c”, and “d” are numbers that satisfy the following conditions: 0≦a≦0.05; 0.9≦b≦1; 0≦c≦0.03; 0≦d≦0.03; and a+b+c+d=1; constituent (A-2) comprises an organopolysiloxane of the following average compositional formula: where R 2 designates phenyl groups, methyl groups, or alkenyl groups having 2 to 10 carbon atoms; 5 to 10 mole % of all R 2 groups are alkenyl groups having 2 to 10 carbon atoms; methyl groups constitute 90 mole % or more of the sum of methyl and phenyl groups contained in R 2 ; “e”, “f”, “g”, “h” and “i” are numbers that satisfy the following conditions: 0.4≦e≦0.6; 0≦f≦0.05; 0≦g≦0.05; 0.4≦h≦0.6; 0.01≦i≦0.05; and e+f+g+h=1; (B) an organopolysiloxane that contains silicon-bonded hydrogen atom and comprises 10 to 50 wt. % of constituent (B-1), 50 to 90 wt. % of constituent (B-2), and 0 to 30 wt. % of constituent (B-3); in an amount that the silicon-bonded hydrogen atoms in component (B) are in the range of 0.5 to 2.0 moles per 1 mole of the total content of alkenyl groups in component (A), wherein constituent (B-1) comprises an organopolysiloxane that contains at least 0.5 wt. % of silicon-bonded hydrogen atoms and that is represented by the following average molecular formula: where R 3 designates phenyl groups or methyl groups; methyl groups constitute 90 mole % or more of all groups contained in R 3 ; “j” is a number in the range of 0 to 35; and “k” is a number in the range of 5 to 100; constituent (B-2) comprises an organopolysiloxane that contains at least 0.5 wt. % of silicon-bonded hydrogen atoms and that is represented by the following average compositional formula: where R 4 designates phenyl groups or methyl groups; methyl groups constitute 90 mole % or more of all groups contained in R 4 ; R 5 designates hydrogen atoms or alkyl groups having 1 to 10 carbon atoms; and “l”, “m”, “n”, “o”, “p” and “q” are numbers that satisfy the following conditions: 0.4≦l≦0.7; 0≦m≦0.2; 0≦n≦0.05; 0≦o≦0.5; 0.3≦p≦0.6; 0≦q≦0.05; and l+m+n+o+p=1; constituent (B-3) is an organopolysiloxane represented by the following average molecular formula: where R 6 represents phenyl or methyl groups; methyl groups constitute at least 90% of all groups contained in R 6 ; and “r” is a number in the range of 10 to 100; and (C) a hydrosilylation-reaction catalyst, in an amount sufficient for curing the composition.