Self-stripping coating composition

Claim 1

In a stable coating composition adapted to simultaneously disperse a previously deposited dried coating composition and replace the dried composition with a fresh coating comprising: 50-96% water, 0-10% plasticizer, 0-5% leveling agent, 0-10% organic solvent, 0-5% surfactant, 0-15% wax, 0-10% film-modifying polymer and 3-18% polymeric coating agent; with the proviso that the total non-volatiles of the composition is in the range of from 4-20% and the combined non-volatiles of the leveling agent, solvent, plasticizer, surfactant, wax and film-modifying polymer are equal to or greater than 9% and less than 200% of the non-volatiles of the polymeric coating agent; the improvement which comprises using as the polymeric coating agent a solution of an alkali-soluble resin having a weight average molecular weight from about 500 to 30,000 and an acid number from about 120 to 550, said resin being an addition resin formed from (a) at least 1 ethylenically unsaturated ligand-free monomer is selected from the group consisting of vinyl toluene, methyl methacrylate, butyl methacrylate, acrylonitrile, vinyl acetate, styrene, α-methyl styrene, butyl acrylate, ethyl acrylate, 2-ethylhexylacrylate and mixtures thereof and (b) at least 1 ethylenically unsaturated monomer having at least 1 carboxyl group is selected from the group consisting of acrylic acid, methacrylic acid, crotonic acid, isocrotonic acid, maleic acid, fumaric acid and itaconic acid, wherein said resins contain from about 40-75% by weight of monomer (a) and from 60-25% by weight monomer (b), wherein the weight ratio of film-modifying polymer to polymeric coating agent is less than 0.57:1, adding aqueous ammonia to said composition in an amount sufficient to provide a pH of no less than 9.0, and said composition being substantially free of complex salts of cross-linking metals.