Patent GB-1019460-A (GB)
Title: Improvements in and relating to coating compositions
IPC: C08G73/10
Filed: 1963-01-03
Abstract: A coating composition comprises a solution in an inert organic liquid of 3 to 75% by weight of the composition of uncondensed polymer forming reactants comprising an aliphatic primary diamine having 2 to 6 carbon atoms, an aromatic diamine having 6 to 36 carbon atoms, an aliphatic-aromatic primary diamine having 7 to 36 carbon atoms or a mixture thereof and a tetracarboxylic compound of the formula <FORM:1019460/C3/1> where R1 is hydrogen or a C1 to C6 alkyl group and R is a carbonyl group or a divalent diamine, diester or dithioester radical, the reactants being present in a proportion from 70% molar excess of the polyame to 5% molar excess of the tetracarboxylic acid.  Specified tetracarboxylic compounds are made by condensing 2 mols. of trimellitic anhydride with 1 mol. of glycol diacetate, triacetin, tolylene diisocyanate-methylene - bis (4 - phenyl isocyanate), oxy bis (p-hydroxyphenyl) propane, ethanolamine, oxydianiline, phenylene diamine, diamino diphenylamine, diaminodiphenyl methane, diamino diphenyl propane, ethylene dithiol, 1-thioglycerol, a :a 1 - dimercapto - p - xylene and 4:41-diamino benzophenone. Specified diamines are those of benzene, naphthalene, diphonyl, diphenyl ether, ditolyl ether, diphenyl sulphide, diphenyl sulphone, diphenyl methane, diphenyl propane and benzophenone: 4:41-thioaniline diphenyl ether, 4:41 - diaminotri-phenylamine, polymethylene polyaniline and the reaction product of a diacyl halide with an excess of a diamine. Triamines may be present in the reaction mixtures.  Specified solvents are the C1 to C6 alkanols, acetone, methyl ethyl ketone, dioxane, cresol, toluol, N-methyl pyrrolidone, dimethyl acetamide, dimethyl formamide and petroleum hydrocarbons. The reactants are condensed by heating at a temperature in the range of 125 DEG  to 400 DEG  C.  Exemplified reactants are: (I) to (III) 4:41-oxydianiline and mixed isomers of the diethyl ester of benzophenone tetracarboxylic acid; (IV) and (X) benzophenone tetracarboxylic acid and 4:41 - diaminodiphenyl methane; (V) benzophenone tetracarboxylic acid dianhydride and 4:41-diaminodiphenyl methane; (VI) benzophenone tetracarboxylic acid dianhydride and (a) oxydianiline; (b) 4:41-diaminodiphenylmethane; (VII) a dianhydride made by reacting 2 mols. of trimellitic anhydride and 1 mol. of ethylene glycol diacetate and 4:41-oxydianiline; (XI) benzophenone tetracarboxylic acid diethyl ester and 4:41-oxydianiline and (XII) the diethyl ester of benzophenone tetracarboxylic acid and m-phenylene diamine.ALSO:A method of making a coated substrate comprises coating a heat resistant substrate with a composition comprising an inert liquid organic solution containing 3-75% by weight of the composition of uncondensed polymerforming reactants comprising an aliphatic primary diamine having 2-6 carbon atoms, an aromatic diamine having 6-36 carbon atoms, an aliphatic-aromatic primary diamine having 7-36 carbon atoms or a mixture thereof and a tetracarboxylic compound of the formula <FORM:1019460/B1-B2/1> where R1 is hydrogen or a C1-6 alkyl group and R is a carbonyl group or a divalent diamine, diester or dithioester radical, the reactants being present in a proportion from 70% molar excess of the polyamine to 5% molar excess of the tetracarboxylic acid, evaporating the solvent, baking the residual film at 125-400  DEG C. to form a cured resin and repeating until the desired coating thickness is attained.  Specified substrates are wire, coils, metallic foil, glass cloth, aluminium panels and cold rolled steel.  Intimate mixtures of the dry solid monomers may be applied using a fluid bed technique.