Siloxane-grafted silica, transparent silicone composition, and optoelectronic device encapsulated therewith

摘要

Silica particles having 4-30% of an organopolysiloxane grafted to surfaces thereof are provided. A silicone composition loaded with such silica particles has high transparency, minimized permeability to corrosive gases, and improved encapsulation ability.

主权项

1. A highly transparent silicone composition, which is addition or condensation curable, comprising
100 parts by weight of a total of silane or siloxane components, and 5 to 400 parts by weight of silica particles having an organopolysiloxane grafted to surfaces thereof by previously admitting 100 parts by weight of silica particles and 10 to 50 parts by weight of the organopolysiloxane in a solvent and heating the mixture under reflux at a temperature of 50 to 200° C. for 1 to 50 hours, said organopolysiloxane having the general formula (1a): wherein R1 is each independently a substituted or unsubstituted monovalent hydrocarbon group of 1 to 10 carbon atoms but not an alkoxy group, R2 is methyl or ethyl, a is an integer of 3 to 50.