| 摘要 |
PURPOSE:To provide the titled composition curable with little generation of H2 gas and composed of an organopolysiloxane, methylhydrogenpolysiloxane, a platinum-based catalyst and a compound containing a alkynyl group. CONSTITUTION:The titled composition is composed of (A) an organopolysiloxane having the average unit of formula II (R is univalent organic group wherein methyl group accounts for >=95mol% thereof; n is 0.1; a is 1.8-2.2) and having the group of formula I at the molecular chain terminal, (B) the methylhydrogenpolysiloxane having the average unit of formula III (R<1> is methyl or H; b is 1.5-3.0) and having >=2 H atoms bonded to Si in one molecule, wherein the molar ratio of the total Si-bonded H to the total aliphatic unsaturated group in the composition is (0.75-0.5):1, (C) >=20ppm (wt.) of a platinum-based catalyst (based on the sum of the components A and B) and (D) a compound containing >=1 alkyl group in one molecule wherein the weight ratio of the total alkyl group to the platinum metal in the composition is (1.0-15.0):1. |
