GB670275A - Protected metal sheets for building purposes - Google Patents

Abstract

A coating composition for application over bituminous materials is made by reacting a polymerizable solvent for bituminous materials with a polyester resin formed by reacting a glycol or mixture of glycols with a dicarboxylic acid ester forming material containing at least 10 mol. per cent of one or more unsaturated a ,b -dicarboxylic acid ester forming substances and the balance comprising aromatic and/or saturated aliphatic ester-forming substances. The polymeriable solvent may be styrene, dichlorostyrene, indene, the coumarone-indene fraction of coal tar distillates, vinyl ketones, vinyl ethers, allyl maleate, allyl phthalate, ethyl acrylate, methyl methacrylate, acrylonitrile or acrolein. The glycols which may be used to form the polyester resin include ethylene glycol, propylene glycol, triethylene glycol, the polyethylene glycols and unsaturated glycols such as vinyl-ethylene glycol. The dicarboxylic ester forming substances include dicarboxylic acids, anhydrides, esters and acid-halides, such as maleic acid or anhydride, fumaric acid, citraconic acid or anhydride, itaconic acid, to which substances may be added phthalic acid or anhydride, tetrachlorophthalic anhydride, succinic, adipic, azelaic or sebacic acids. Monohydric alcohols, e.g. allyl or crotyl alcohol, and/or monocarboxylic acids, e.g. acrylic or crotonic acid may be included as modifiers in the preparation of the polyester resin. Pigments, fillers and catalysts may be added to the coating composition. The catalysts may be chain initiating catalysts such as acetyl peroxide, lauryl peroxide, stearyl peroxide, benzoyl peroxide, tertiary butyl perbenzoate, tertiary butyl hydroperoxide, or catalysts to complete polymerization at the surface of the coating where it is in contact with oxygen such as cobalt nitrate or cobalt naphthenate. The coating may be cured at elevated temperature or by adding cuprous oxide or cuprous salts may polymerize at ordinary temperatures. In an example, diethylene glycol, maleic anhydride, phthalic anhydride and p-toluenesulphonic acid were reacted together to obtain a liquid polyester which was made into a coating composition with styrene, titanox B 30, chrome oxide green, and cobalt nitrate to which was added benzoyl peroxide as a paste in tricresyl phosphate. Specification 106,997, [Class 140], and 467,142, [Group VIII], are referred to.