Patent ID: 8258636

Claim:
A curable liquid polysiloxane/TiO 2 composite for use as a light emitting diode encapsulant, comprising: a polysiloxane prepolymer with TiO 2 domains having an average domain size of less than 5 nm; wherein the polysiloxane prepolymer has an average compositional formula: (R 4 3 SiO 1/2 ) a (R 1 (R 2 )SiO 2/2 ) b (R 3 SiO 3/2 ) c (R 5 x Z y SiO (4-x-y)/2 ) d wherein each R 1 and R 3 is independently selected from a C 6-10 aryl group and a C 7-20 alkylaryl group; wherein each R 2 is a phenoxyphenyl group; wherein each R 4 is independently selected from a C 1-10 alkyl group, a C 7-10 arylalkyl group, a C 7-10 alkylaryl group and a C 6-10 aryl group; wherein each R 5 is independently selected from a C 1-10 alkyl group, a C 7-10 arylalkyl group, a C 7-10 alkylaryl group, a C 6-10 aryl group and a phenoxyphenyl group; wherein each Z is independently selected from a hydroxyl group and a C 1-10 alkoxy group; wherein 0≦a≦0.005; wherein 0.8495≦b≦0.9995; wherein 0.0005≦c≦0.10; wherein 0≦d≦0.15; wherein the curable liquid polysiloxane/TiO 2 composite contains 20 to 60 mol % TiO 2 (based on total solids); wherein each x is independently selected from 0, 1 and 2; wherein each y is independently selected from 1, 2 and 3; wherein a+b+c+d=1; and, wherein the curable liquid polysiloxane/TiO 2 composite exhibits a refractive index of >1.61 to 1.7 and wherein the curable liquid polysiloxane/TiO 2 composite is a liquid at room temperature and atmospheric pressure.