Patent ID: 8455607

Claim:
A curable liquid polysiloxane/TiO 2 composite for use as a light emitting diode encapsulant, comprising: a polysiloxane with TiO 2 domains having an average domain size of less than 5 nm; wherein the polysiloxane has an average compositional formula: (R 3 4 SiO 1/2 ) a (R 1 (R 2 )SiO 2/2 ) b (R 3 SiO 3/2 ) c (R x 5 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 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; wherein the polysiloxane comprises, as initial components: (i) D units having a formula R 1 (R 2 )Si(OR 6 ) 2 ; (ii) T units having a formula R 3 Si(OR 7 ) 3 ; (iii) optionally, M units having a formula R 3 4 SiOR 8 ; and, (iv) optionally, Q units having a formula Si(OR 9 ) 4 ; wherein each R 6 , R 7 , R 8 and R 9 is independently selected from a hydrogen atom, 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 the D units contain >1 ppb to ≦100 ppm in combined total of all target contaminants having formulae selected from R 1 —O—(R 2 )Si(OR 6 ) 2 ; R 2 —O—(R 1 )Si(OR 6 ) 2 ; R 1 (R 10 )Si(OR 6 ) 2 ; and, R 2 (R 11 )Si(OR 6 ) 2 ; wherein R 10 is selected from a phenol-oxy-phenyl group and a phenyl-oxy-(hydroxy)phenyl group and wherein R 11 is a hydroxyphenyl group; wherein the curable liquid polysiloxane/TiO 2 composite contains 20 to 60 mol % TiO 2 (based on total solids); 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.