主权项 |
1. An encapsulant for optical semiconductor devices, which comprises: a first organopolysiloxane having an alkenyl group and a methyl group bonded to a silicon atom;
a second organopolysiloxane having a hydrogen atom bonded to a silicon atom and a methyl group bonded to a silicon atom; and a catalyst for hydrosilylation reaction, wherein the first organopolysiloxane is a first organopolysiloxane represented by the following formula (1A) and the second organopolysiloxane is a second organopolysiloxane represented by the following formula (51A), or the first organopolysiloxane is a first organopolysiloxane represented by the following formula (1B) and the second organopolysiloxane is a second organopolysiloxane represented by the following formula (51B), and the content ratios of methyl groups bonded to silicon atoms in the first organopolysiloxane and the second organopolysiloxane each are 80 mol % or more.
[Formula 1](R1R2R3SiO1/2)a(R4R5SiO2/2)b(R6SiO3/2)c Formula (1A) In the formula (1A), a, b and c satisfy a/(a+b+c)=0 to 0.30, b/(a+b+c)=0.70 to 1.0 and c/(a+b+c)=0 to 0.10, at least one of R1 to R6 represents an alkenyl group, at least one of R1 to R6 represents a methyl group, and R1 to R6 other than an alkenyl group and a methyl group represent a hydrocarbon group having 2 to 8 carbon atoms.
[Formula 2](R51R52R53SiO1/2)p(R54R55SiO2/2)q(R56SiO3/2)r Formula (51A) In the formula (51A), p, q and r satisfy p/(p+q+r)=0.10 to 0.50, q/(p+q+r)=0 to 0.40 and r/(p+q+r)=0.40 to 0.90, at least one of R51 to R56 represents a hydrogen atom, at least one of R51 to R56 represents a methyl group, and R51 to R56 other than a hydrogen atom and a methyl group represent a hydrocarbon group having 2 to 8 carbon atoms.
[Formula 3](R1R2R3SiO1/2)a(R4R5SiO2/2)b(R6SiO3/2)c Formula (1B) In the formula (1B), a, b and c satisfy a/(a+b+c)=0.10 to 0.50, b/(a+b+c)=0 to 0.40 and c/(a+b+c)=0.40 to 0.90, at least one of R1 to R6 represents an alkenyl group, at least one of R1 to R6 represents a methyl group, and R1 to R6 other than an alkenyl group and a methyl group represent a hydrocarbon group having 2 to 8 carbon atoms.
[Formula 4](R51R52R53SiO1/2)p(R54R55SiO2/2)q(R56SiO3/2)r Formula (51B) In the formula (51B), p, q and r satisfy p/(p+q+r)=0 to 0.30, q/(p+q+r)=0.70 to 1.0 and r/(p+q+r)=0 to 0.10, at least one of R51 to R56 represents a hydrogen atom, at least one of R51 to R56 represents a methyl group, and R51 to R56 other than a hydrogen atom and a methyl group represent a hydrocarbon group having 2 to 8 carbon atoms. |