GB1123303A - Production of pigmented resinous compositions - Google Patents

Abstract

Pigmented compositions comprise a pigment dispersed in a vehicle comprising an iminemodified polymer containing at least 0.1% by weight of carboxylic acid units which have been reacted with an alkylenimine or substituted alkylenimine. Pigments which may be used include carbon black, titanium dioxide, phthalocyanine blue or green, red or yellow iron oxide, transparent orange or red iron oxide, indo red or yellow, molybdate orange, monastral violet, ultramarine blue and cadmium red. The polymer which is iminated is preferably an interpolymer of an ester of an ethylenically unsaturated carboxylic acid; the acid component may be copolymerized with such ester or be present in another polymer which is blended with the ester polymer. Other acid polymers which may be iminated include alkyds, e.g. the product derived from coconut fatty acid, trimethylol ethane, p-t-butylbenzoic acid and phthalic anhydride, and other polycarboxylic acid resins. Suitable acid monomers which may be used in, or with, the ester polymers are acrylic, methacrylic and related a -substituted acrylic acids, maleic acid, fumaric acid and half-esters of such dibasic acids, crotonic acid, 3-butenoic acid, tiglic acid and itaconic acid and its half-esters; copolymerizable fatty acids such as dehydrated castor oil acids may also be used. The ester component of the polymer may be an alkyl methacrylate or an hydroxy alkyl ester of an ethylenically unsaturated carboxylic acid; additional units of the polymer are derived, for example, from alkyl acrylates, acrylonitrile, methacrylonitrile, butadiene, vinyl acetate, vinyl chloride, dibutyl maleate, styrene vinyl toluene, a -alkyl styrenes, dibutyl maleate, glycidyl methacrylate or dimethylbenzyl acrylate. The iminating agent is an alkylenimine which may contain substituents such as aryl, alkaryl, aralkyl, cyano, halo, amino, hydroxy, alkoxy, carbalkoxy and nitrile; preferred compounds are those of 2 to 4 carbon atoms, e.g. ethylenimine, 1,2 - propylenimine and N-(2 - hydroxy ethyl) - ethylenimine. Imination is effected by heating the components, e.g. at 50-150 DEG C. and may take place during or after polymerization. Polymerization of the starting monomers is generally effected using a peroxy catalyst, e.g. cumene hydroperoxide or benzoyl peroxide, or an azo catalyst, and in the presence of an organic solvent, e.g. xylene/butanol or toluene, which remains as part of the dispersing vehicle; a mercaptan may also be present. Additional solvent may also be included in the pigment composition, e.g. butanol, toluene, xylene, acetone, methyl ethyl ketone or ethylene glycol ethyl ether acetate. p-Phenylenediamine may also be added, and in one example a carbon black dispersion is formulated into a black enamel by mixing with a butylated melamine-formaldehyde resin, and cured coatings are prepared therefrom.ALSO:In an Example, steel panels are sprayed with a black enamel composition comprising in an organic solvent (a) an interpolymer of n-butyl methacrylate, methyl methacrylate, ethyl acrylate, 2-hydroxy-n-propyl methacrylate and methacrylic acid, wherein the acid groups have been reacted with 1,2-propylenimine (b) carbon black (c) p-phenylene diamine and (d) butylated melamine-formaldehyde resin, and then baked at 250 DEG C. for 30 minutes. In similar Examples (i) the 1, 2-propylenimine is replaced by ethylenimine and (ii) component (c) is omitted.