| 摘要 |
PURPOSE:To provide the titled composition having excellent adhesivity to substrate, resistant to the internal crack of gel and the peeling from the substrate caused by thermal shock, and capable of forming a gel resistant to discoloration and variation of physical properties at high temperature, by compounding a specific polyorganosiloxane with specific amount of a specific siloxane and a catalyst. CONSTITUTION:The objective composition can be produced by compounding (A) a polyorganosiloxane having a viscosity of 50-10,000cp and containing 0.1-2 vinyl groups bonded to Si atom in one molecule, wherein the other organic group bonded to the Si atom is a (substituted) univalent hydrocarbon group free from aliphatic unsaturated bond (e.g. methyl group) with (B) a siloxane of formula (R<1> is 1-4C alkyl or phenyl; R<2> is 1-4C alkyl) and (C) a catalyst selected from platinum-based catalyst, palladium-based catalyst and rhodium-based catalyst. The number of H atoms bonded to Si atom of the component B is 0.1-0.8 or 1.5-3.0 based on one vinyl group bonded to Si atom of the component A, and the amount of metallic element of the component C is 0.01-30ppm based on the sum of the components A and B. |
