Water-soluble air-oxidizing acrylic coatings

Claim 1

In a method of coating an article with a paint containing an aqueous alkaline solution of an addition polymer solubilized in said solution by a volatile amine or ammonia, said solubilized polymer having the structure: ##STR11## wherein R 1 is H, a lower alkyl radical having one to five carbon atoms, halogen, --CN, or --CH 2 COOR, --COOR, or --CH 2 COOH, R being a lower alkyl radical having from one to eight carbon atoms; R 2 is (CR 7 2 ) n wherein R 7 is --H or --CH 3 and n is 1 or 2; R 3 is H, or a lower alkyl radical having from one to 8 carbon atoms; R 4 is an unsaturated, air-curable alkyl radical; R 5 is H, --COOH, --CONH 2 , or --COOR, wherein R is as above; R 6 is H, or an aliphatic or cycloaliphatic radical having from one to 20 carbon atoms; and X is optional and when present is derived from at least one vinyl monomer different than the residues depicted; the units in brackets being in any order, portions of the R 6 radicals being as hereinafter defined in units of the formula: ##STR12## R 6 being H in a sufficient number of units of Formula II to provide the polymer with a carboxy content of 0.5-6 meq/g. of polymer, the quantity of carboxy groups being sufficient, when in the form of salt groups with said amine or ammonia, to confer water solubility upon the polymer, the amount of carboxy-containing units of Formula II wherein R 6 is H being between 5 and 40 parts by weight of the total polymer; optionally a portion of the radical R 6 in the units of Formula II being at least one aliphatic or cycloaliphatic radical and being selected so that the units are derived from at least one ester which when homopolymerized gives a high molecular weight polymer having a T g of between -80° C. and 120° C., said ester units forming up to 90 parts by weight of the polymer; the polymer having between about 5 and 60 parts by weight of units of the formula: ##STR13## wherein R 1 , R 2 , R 3 , R 4 , and R 5 are as identified above, any balance of the polymer being the units of --X-- of addition polymerized ethylenically unsaturated monomers other than said units of Formulas II and V, the total parts of all said units being 100, the Mv of the polymer being between about 5,000 and 200,000, the T g of a cured film of the polymer being between about -20° C. and 80° C., the Tukon Hardness of the cured film being between about 0.2 and about 15, in which the composition optionally includes a metal compound drier in an amount up to 0.5%, on a metal basis, of the total polymer weight in the composition, applying a thin uniform coating of the aqueous solution to a substrate, and drying and curing said coating in the presence of air.