Abstract This invention relates to aqueous "multi-pack" coating compositions, that is, those which comprise at least two discrete components (or "packs") which are mixed prior to application. Prior attempts to provide an aqueous multi-pack composition have failed to provide a suitable combination of the desirable characteristics of adequate "pot-life" (the time for which the mixed components remain workable) and early development of adequate mechanical properties. The compositions of the present invention which provide such a combination consist of a number of components which together comprise a constituent having epoxide groups, a constituent comprising addition polymer in the form of an aqueous dispersion and a constituent capable of reacting with epoxide groups. In an especially preferred embodiment, the aqueous addition polymer dispersion is combined with at least one of the other constituets in the form of a multi-polymer particle dispersion. The compositions are useful in the automotive refinish and heavy duty coatings areas.
A method of forming an aqueous coating composition comprising polymerizing monoethylenically unsaturated monomers in an aqueous dispersion in the presence of a dispersed epoxy resin to form an aqueous dispersion copolymer, the copolymer of said monoethylenically unsaturated monomers having a glass transition temperature in the range of about -55° C. to about 105° C., and then mixing the aqueous dispersion of copolymer and epoxy resin formed by said polymerization with an amine-functional resin in an amount to supply a weight ratio of amino hydrogen atoms to oxirane group of from 0.2 to 1.5.
Claim 2
Independent Claim
93 words
A method of forming an aqueous coating composition comprising polymerizing monoethylenically unsaturated monomers in an aqueous dispersion in the presence of a dispersed epoxy resin to form an aqueous dispersion copolymer, the copolymer of said monoethylenically unsaturated monomers having a glass transition temperature in the range of about -55° C. to about 105° C., and then mixing the aqueous dispersion of copolymer and epoxy resin formed by said polymerization with an amine-functional resin in an amount to supply a weight ratio of amino hydrogen atoms to oxirane group of from 0.2 to 1.5.