Patent GB-561800-A (GB)
Title: Improvement in lacquers
IPC: C09D127/06
Filed: 1940-09-20
Abstract: A lacquer particularly suited for use on smooth surfaces, e.g of glass or metal comprises a resin obtained by the co-polymerisation of a vinyl halide, e.g. the chloride or bromide and a vinyl ester of a lower aliphatic acid, e.g. vinyl formate, acetate, propionate or butyrate in the presence of a modifying agent, selected from maleic acid, maleic anhydride, mono esters of maleic and fumaric acids, derivatives of these compounds obtained by replacing an a  hydrogen atom by an alkyl, alkenyl, aryl or aralkyl radical and crotonic acid, the resin containing 0.1 per cent to 10 per cent of the modifying agent.  The resin preferably contains 60-95% of vinyl chloride and has an average molecular weight between 6,000 and 14,000.  Baked finishes may be obtained at normal baking temperatures, e.g. 107 DEG -149 DEG  C.  The optumin content of modifying agent in the resin varies for each compound. For maleic acid it lies between 0.3 per cent and 3 per cent.  The modified resins in the lacquers may be blended with similar unmodified resins.  The lacquer may be used as a primer coating for other lacquer coatings which may contain the modified resin, the unmodified resin, a mixture of both or which may contain other resinous materials, e.g. methyl methacrylate polymer, or highly polymerised polyvinyl chloride.  Suitable solvents for the lacquer composition are methyl isobutyl ketone, acetone, methyl ethyl ketone, mesityl oxide, cyclohexanone and isophorone. Suitable diluents which may be included are toluene, xylene and tetrahydronaphthalene.  Plasticisers may be present, e.g. di (b -butoxyethyl)phthalate, tricresyl phosphate, dibutyl phthalate, diethyl phthalate, or triglycol di(2-ethyl hexoate). Pigments, gums, stabilisers or dyes may also be added.  A typical example describes the preparation of a lacquer containing 13 per cent of a polymer from 84.7 per cent vinyl chloride, 14.8 per cent vinyl acetate and containing .5 per cent maleic acid, having an average molecular weight of 81,400, unmodified vinyl chloride vinyl acetate polymer (86-88 per cent vinyl chloride-average molecular weight 9,000-10,000) 2 per cent; lead chromate 10.5 per cent; toluene 36.2 per cent; methyl isobutyl ketone 36.2 per cent; di(b -butoxyethyl)phthalate 2 per cent; blown castor oil 1 per cent.  Two coats sprayed on to a steel panel and baked for 30 minutes at 121 DEG  C. yielded a tough, adherent film with good resistance to water and chemicals.  Other examples specify also as ingredients of lacquer compositions:-titanium oxide, antimony oxide, lead titanate, and carbon black as pigments, maleic anhydride, mono-2-ethyl hexyl maleate, and mono ethyl fumarate as modifiers, and modified resins with different proportions of vinyl chloride and vinyl acetate. Various combinations of primers and other coatings are described and protective finishes are described suitable for use in chemical plant, dairies, lining storage tanks, inside and outside decoration, or for protecting hard rubber battery boxes against attack by sulphuric acid.  If higher boiling solvents and diluents are used, the lacquers may be applied by roller coating.  Specifications 376,479, 466,898 and 467,167 are referred to.