Water-extendible oligomer solutions and coatings therefrom

Claim 1

Coating solution consisting essentially of: (a) about 30 to 75 wt % of the following non-volatile ingredients which are present in amounts, relative to each other: (i) 30 to 80 wt % of an oligomer having a degree of polymerization (DP) of about 10 to about 50 and a polyalkylene ether glycol having a molecular weight of about 400 to about 1300, the amount of glycol being 0 to 60 wt % of the amount of oligomer; (ii) 2 to 12 wt % of a non-volatile, water-miscible compound selected from p-toluenesulfonic acid, trifluorosulfonic acid, 5-sulfosalicyclic acid, 1-naphthalene-sulfonic acid, 2,5-dimethylbenzene-sulfonic acid, the sodium salts of the above acids, the sodium salts of aliphatic monocarboxylic acids having 6 to 12 carbon atoms, ammonium benzoate, and sodium di-2-ethylhexylsulfosuccinate; (iii) 5 to 65 wt % of an amine-aldehyde cross-linking resin; and (iv) 0 to 10 wt % of an acidic curing catalyst; and (b) 25 to about 70 wt % of the following volatile ingredients which are present in amounts, relative to each other: (i) 5 to 70 wt % of water-miscible organic solvent; and (ii) 30 to 95 wt % of water, with the sum of the weight percentages being 100% for each of (a) and (b); (i), (ii), (iii) and (iv) of (a); and (i) and (ii) of (b), and with the proviso that the amounts of non-volatile ingredients, water and organic solvent are such that the coating solution contains not more than 250 g of volatile organic compounds per liter of solution, excluding water, the oligomer of (a) (i) being prepared by uniformly copolymerizing, using free radical initiation, in the presence of about 0.5 to about 10 wt % of a mercaptan of the formula R 2 SH wherein R 2 is hydroxyalkyl or alkyl of 2 to 10 carbon atoms: (a) 0 to about 80 wt % of a monomer selected from vinyl acetate, vinyl propionate, N-vinyl pyrrolidone, acrylamide, acrylonitrile, vinyl chloride, methyl vinyl ether, ethyl vinyl ether, and styrene; provided, however, the amount of styrene shall not exceed 60 wt %; (b) about 5 to about 50 wt % of a monomer selected from hydroxyethyl and hydroxypropyl acrylates and methacrylates; and (c) 0 to about 80 wt % of a monomer selected from alkyl acrylates and alkyl methacrylates, wherein alkyl is of 1 to 8 carbon atoms, with the sum of the weight percentages being 100%.