GB908776A - Anti-corrosion, amino-organosilicon-epoxy coating compositions - Google Patents

Abstract

Metal surfaces are coated to improve their resistance to corrosion by applying thereto a composition comprising an epoxy compound and at least one amino-organosilicon compound selected from hydrolysable silanes in which the amino group, containing 1 or 2 H atoms bonded to N, is connected to Si by not less than 3C atoms, and siloxane polymers and co-polymers obtainable from such silanes with or without conventional silanes and/or siloxanes (see Group IV(a)), and curing the composition on the surface. Articles and surfaces to be protected may be made of aluminium, brass, bronze, copper, chromium plate, iron, magnesium, nickel, lead, steel, silver, silver-plate, sterling silver, ternplate (tinplate), tin, beryllium, bronze and zinc. The compositions may contain diluents which include volatile solid or liquid hydrocarbons, chlorinated hydrocarbons, nitrogenated paraffins, hydrocarbon ethers and alcohols, which may be solvents for the compositions or non-solvents therefor, in which case an emulsifier must be used and other additives, e.g. ketones, aldehydes, esters, acids, pigments other colourants, fillers, waxes, plasticizers and resins. The compositions may be ripened (i.e. partially reacted) prior to application to the article to be coated and can be applied in the form of solvent solutions, emulsions, or dispersions in aqueous or non-aqueous liquid or solid systems, e.g. by dipping, brushing, trowelling or spraying, or, as aerosols, and the resulting coatings are then dried or cured at atmospheric or elevated temperatures. A plurality of coats may be applied. Examples are given describing the coating of (4, 5, 14, 15, 16, 20, 22, 23) steel panels, (6) stainless steel panels, (7) rolled steel, (8) galvanized steel, (9, 10) silver teaspoons, (11) sterling silver and silver-plated creamers and sugar tableware, (12, 13) copper panels, (17) panels of magnesium, zinc, beryllium-copper alloy, brass, steel, nickel and tin-plated steel, (18) chrome plated steel panels, (19) aluminium panels and (21) brass panels. Reference has been directed by the Comptroller to Specification 810,284.ALSO:A coating composition comprises an epoxy compound, a volatile organic diluent and at least one amino-organosilicon compound selected from hydrolysable silanes in which the amino group, containing 1 or 2 H atoms, bonded to N, is connected to Si by not less than 3 C atoms, and siloxane polymers and copolymers obtainable from such silanes with or without conventional silanes and/or siloxanes. The epoxy compound is used in amount, e.g. to provide from 0,05 to 5,0 epoxy equivalents for each amino hydrogen equivalent provided by the aminoalkylsilicon compound. Many examples are given of (a) aminoalkylsilicon compounds (silanes and siloxane cyclics, oils, gums and resins) containing Si-bonded alkyl, aryl, alkenyl, hydroxy and alkoxy radicals, and (b) organo mono- and poly-epoxides. Diluents are also abundantly exemplified and include volatile solid and liquid hydrocarbons, chlorinated hydrocarbons, nitrogenated paraffins, hydrocarbon ethers and alcohols, which may be solvents for the organosilicon-epoxy mixture or non-solvents therefore, in which case an emulsifier must be used. Ketones, aldehydes, esters, acids, pigments, other colorants, fillers, waxes, plasticizers and resins, may also be added. The mixtures can be partially reacted or ripened prior to application to the article to be coated, and can be applied in the form of solvent solutions, emulsions or dispersions in liquid or solid systems or aerosols, and the resulting coatings are then dried or cured at atmospheric or elevated temperatures. In typical examples, a coating composition is formed (1) by refluxing a mixture of g -aminopropyl phenylsiloxane copolymer, ethylene glycol monomethyl ether, toluene and diglycidyl ether of bisphenol A; (2) storing at 70 DEG C. for 4 days a mixture of NH2(CH2)3Si(OEt)3, C6H5Si(OEt)3 and diglycidyl ether of bisphol A. Uses: For coating metal surfaces to inhibit corrosion (see Group III). Reference has been directed by the Comptroller to Specification 810,284.