GB472249A - The protection of metallic surfaces - Google Patents

Abstract

Metallic surfaces liable to be in a humid state, e.g. iron or other metallic structures such as bridges, or pipes in a refrigerating plant, are protected independently of their state of humidity by applying thereto a paint in which, as employed, two or more volatile ingredients are capable of forming with such water as may be found on a metallic surface as aforesaid a ternary or higher azeotropic mixture having a minimum boiling point. The paint may be prepared from linseed or wood oil or both and colophonic esters, phenol resins containing colophonic esters, oil-modified polyhydric alcohol-phthalic anhydride resins, or coumarone, and diluted with at least 5 per cent of a liquid boiling below about 225 DEG C. at normal atmospheric pressure and being substantially miscible with water, or with a mixture of liquids, which mixture may comprise one or more liquids immiscible with water. Diluents may be chosen by test from among alcohols, e.g. ethanol, butanol, diacetone alcohol; esters; ketones, e.g. methyl ethyl ketone; glycol derivatives, e.g. glycol monoethyl or monobutyl ether; benzene and its homologues; solvent naphtha; turpentine: examples are ethanolbenzene, and propanol-benzene. In examples: (1) wood oil-rosin ester varnish comprising solvent naphtha is diluted with alcohol and toluene; (2) liquid oil-modified polyhydric alcohol-phthalic anhydride resin is diluted with ethanol and butanol, and titanium white added.ALSO:Metallic surfaces liable to be in a humid state, e.g. iron or other metallic structures such as bridges, or pipes in a refrigerating plant, are protected independently of their state of humidity by applying thereto a paint in which, as employed, two or more volatile ingredients are capable of forming with such water as may be formed on a metallic surface as aforesaid, an at least ternary azeotropic mixture having a minimum boiling point. The paint may be prepared from linseed or wood oil or both, and colophony or its esters, phenol resins containing colophonic esters, copal extracted by melting, oil-modified polyhydric alcohol-phthalic anhydride resins, or coumarone, and diluted with at least 5 per cent of a liquid boiling below about 225 DEG C. at normal atmospheric pressure and being substantially miscible with water, or with a mixture of liquids which mixture may comprise one or more liquids immiscible with water. Diluents may be chosen by test from among alcohols, e.g. ethanol, butanol, diacetone alcohol; esters; ketones, e.g. methyl ethyl ketone; glycol derivatives, e.g. glycol monoethyl or monobutyl ether; benzene and its homologues; solvent naphtha; turpentine: examples are ethanol-benzene, and propanolbenzene. In examples: (1) wood oil-rosin ester varnish comprising solvent naphtha is diluted with alcohol and toluene; (2) liquid oil-modified polyhydric alcohol-phthalic anhydride resin is diluted with ethanol and butanol and titanium white added; (3) linseed oil or stand oil is diluted with glycol monoethyl ether and butanol, and zinc white added.