PROCESS FOR PRIMING AND COMPOSITIONS THEREFOR

摘要

1529362 Organo-silicon containing coating compositions DOW CORNING CORP 8 Oct 1975 [15 Oct 1974] 41203/75 Headings C3T and C3B [Also in Division B2] A film-forming composition comprises a homogeneous solution of (A) from 0À99 to 15% wt. of a compound selected from (1) compounds of the formula (RO) 4-a SiZ a , (2) curable reaction products of (a) silanes of the formula and (b) epoxy compounds soluble in (C) + (D) + (E) below and (3) siloxanes which are condensation and co-condensation products of (1) and (2), (B) from 0À01 to 10% wt., of at least one primer-soluble, light-fugitive colourant which will retain at least some of its colour for at least 24 hours and will subsequently become colourless, i.e. within a time period from 1 day to 6 weeks, in the presence of light, (C) from 1- 85% wt. of a solvent of the formula (D) from 1-85% wt. of a hydrocarbon solvent with a boiling point from 50‹ to 250‹ C., and (E) from 1-85% wt. of a solvent of the formula CH 3 CO(OCH 2 CH(Q)) y OR111, where a is 0 to 1, n is 3-9, y is 0-2, Q is hydrogen or methyl, R is an alkyl, cycloalkyl or alkoxyalkyl group containing less than 7 carbon atoms, R1 is hydrogen or a -C m H 2m NH 2 group where m is 2-4, R111 is an aliphatic or cycloaliphatic hydrocarbon radical containing not more than 9 carbon atoms, and Z is an alkyl, vinyl, phenyl or -C n H 2n NHR1 group, any nitrogen atom being bonded to Si atoms through at least 3 carbon atoms, the percentages being based on the total weight of the composition. Suitable colourants are amaranth, brilliant blue, anthraquinone violet B, cyanine green, erythrosine, fluorescein, indigo carmine, metanil, yellow, sunset yellow, tartrazine, Violamine R, Congo red, primulin, auramine and safranin Y. Suitable solvents (C) are methanol, butanol, isopropanol, cyclohexanol, monoalkyl ethers of ethylene glycol, propylene glycol, diethylene glycol and dipropylene glycol. Suitable solvents (D) are benzene, toluene, xylene, cyclohexane, cyclohexene, heptane and petroleum naphtha. Suitable solvent (E) is ethoxyethylacetate. The compositions are used as primers on surfaces which are to be coated with silicone containing coating compositions, e.g. metals, such as Al, Fe, Cu and their alloys; wood; cementitious materials; marble, ceramics and glass; painted surfaces and porous plastics such as polyurethane foam and nylon cloth. In the examples a primer composition is prepared by dissolving a solid epoxy resin in a mixture of 2-methoxyethanol, toluene and 2- ethoxyethyl acetate, then adding aminoethylaminopropyl - trimethoxysilane and then an aqueous solution of tartrazine, brilliant blue and sunset yellow. The primer is either applied to concrete, marble and plywood surfaces and dried in air, or applied to a polyurethane foam surface, dried after which the primed foam is coated with a RTV organo-silicon containing coating composition.