| 摘要 |
PURPOSE:To provide the titled compsn. having excellent transparency, non-fluidity, resistance to heat and weather, etc. and suitable for use in opticl field, consisting of a specified organopolysiloxane and fine silica powder. CONSTITUTION:100pts.wt. organopolysiloxane (A) having a refractive index of 1.45-1.48 at 25 deg.C, a viscosity of 10-50,000cps at 25 deg.C and an average composition of the formula (wherein R is a monovalent hydrocarbon group contg. at least 50mol% of methyl group and 5-20% of phenyl group; a is an average of 1.8-2.2) and 0.5-50pts.wt. fine silica powder (B) having a particle size of 100mmu or below treated with 0.5-60wt% (based on the quantity of silica powder) silane or polysiloxane contg. an average of 0.1-2.5 hydroxyl groups or hydrolyzable groups per one Si atom and an average of 0.2-3.0 phenyl groups per one Si atom, are mixed together at room temp. or under heating. |
