| 主权项 |
1. A curable silicone composition comprising:
(A) 100 parts by mass of an organopolysiloxane represented by the following average unit formula:
(R13SiO1/2)a(R12SiO2/2)b(R1SiO3/2)c(SiO4/2)d(R2O1/2)e wherein each R1 is independently a phenyl group, a C1-6 alkyl group, or a C2-6 alkenyl group; however, from 30 to 80 mole % of all groups designated by R1 are phenyl groups and from 5 to 20 mole % of all groups designated by R1 are alkenyl groups; R2 is a hydrogen atom or a C1-6 alkyl group; and “a”, “b”, “c”, “d”, and “e” are numbers that respectively satisfy: 0≦a≦0.3, 0≦b≦0.7, 0.3≦c≦0.9, 0≦d≦0.1, 0≦e≦0.1, and a+b+c+d=1; (B) 5 to 50 parts by mass of an organopolysiloxane that has not more than 10 silicon atoms wherein from 30 to 60 mole % of all silicon-bonded organic groups are C2-6 alkenyl groups; (C) 0 to 40 parts by mass of an organopolysiloxane represented by the following general formula:
R33SiO(R32SiO)mSiR33 wherein each R3 independently represents a phenyl group, a C1-6 alkyl group, or a C2-6 alkenyl group; however, from 30 to 70 mole % of all groups designated by R3 are phenyl groups and at least one of all groups designated by R3 is an alkenyl group; and “m” is an integer from 10 to 100; (D) an organopolysiloxane that has at least two silicon-bonded hydrogen atoms in one molecule wherein from 20 to 70 mole % of all silicon-bonded organic groups are phenyl groups, in an amount that provides from 0.5 to 2 moles of silicon-bonded hydrogen atoms in this component per 1 mole of the total amount of the alkenyl groups in components (A), (B), and (C); (E) a hydrosilylation reaction catalyst in a quantity sufficient to accelerate the hydrosilylation reaction between the alkenyl groups in components (A), (B), and (C) and the silicon-bonded hydrogen atoms in component (D); (F) a white pigment in an amount of at least 25 parts by mass per 100 parts by mass of the total amount of components (A), (B), (C), (D), and (E); (G) a nonspherical silica or a glass fiber in an amount of at least 20 parts by mass per 100 parts by mass of the total amount of components (A), (B), (C), (D), and (E); and (H) a spherical silica in an amount of at least 20 parts by mass per 100 parts by mass of the total amount of components (A), (B), (C), (D), and (E), wherein the content of the total amount of components (F), (G), and (H) is not more than 300 parts by mass per 100 parts by mass of the total amount of components (A), (B), (C), (D), and (E). |
