Transparent shatter-resistant silicone coating

Claim 1

A transparent and fast curing composition suitable for use as a shatter-resistant coating on a glass, porcelain or ceramic surface, wherein the composition comprises: (A) from 62 to 71 parts by weight of a solid, benzene soluble resin copolymer consisting essentially of R 3 SiO 1/2 units and SiO 4/2 units where each R individually is a monovalent hydrocarbon radical containing no more than six carbon atoms, there being from 0.6 to 0.9 inclusive R 3 SiO 1/2 units for every SiO 4/2 unit, at least 95 percent of all radicals in (A) being methyl and the total number of R radicals in (A) that have olefinic unsaturation being 0-0.5 percent of all R radicals in (A), (B) from about 29 to about 38 parts by weight of an essentially cyclic free, polydiorganosiloxane of the average formula R.sup.1.sub.2 R.sup.2 SiO(R.sup.1.sub.2 SiO).sub.m (R.sup.1 R.sup.2 SiO).sub.n SiR.sup.2 R.sup.1.sub.2 where each R 1 individually is a radical selected from the group consisting of methyl, ethyl, propyl, and phenyl, at least 95 percent of all R 1 radicals being methyl, each R 2 individually is a vinyl radical or any R 1 as defined above with the proviso that at least 2 R 2 radicals must be vinyl and m+n has an average value such that the viscosity of the polydiorganosiloxane (B) has a value of from about 500 to about 1,000,000 centipoises at 25° C., the total of (A) and (B) being 100 parts by weight; (C) an amount of an organopolysiloxane compatible with the mixture of (A) and (B) and having an average unit formula R.sup.3.sub.a H.sub.b SiO.sub.(4--a--b)/2 where each R 3 individually is any R 1 radical as defined above, a has a value of from 1.00 to less than 2.00, b has a value of from 0.05 to 1.00, the sum of a plus b being from 1.10 to less than 3.00, there being an average of greater than two silicon bonded hydrogen atoms per molecule of (C), no silicon atom bearing more than one silicon bonded hydrogen atom and the amount of (C) present being sufficient to provide from 1.0 to 30.0 silicon bonded hydrogen atoms for every olefinically unsaturated radical in the total of (A) plus (B) and, (D) a platinum-containing catalyst in sufficient quantity to provide at least 0.1 part by weight of platinum for every one million parts by weight of the combined weight of (A), (B), and (C).