| abstract |
Aqueous-based cross-linkable binder composition comprising(A) an aqueous dispersion of a polyester-polyacrylate hybrid resin 50 to 90 wt. % of which is composed of polyester and 10 to 50 wt. % of which is composed of polyacrylate, which hybrid resin is obtainable by grafting a composition of radically polymerisable unsaturated monomers onto a partially unsaturated hydroxy-functional polyester resin, and(B) an organic polyisocyanate, whereinthe partially unsaturated hydroxy-functional polyester is obtainable by reaction of a mixture of polycarboxylic and, optionally, monocarboxylic acids, and one or more (cyclo)aliphatic alcohols, wherein 0.5-6 mole % of the acids or alcohols are ethylenically unsaturated, andthe composition of radically polymerisable unsaturated monomers comprises a mixture of hydrophobic and hydrophilic monomers, wherein(a) the hydrophobic monomers are selected from the group of aromatic vinyl compounds and (cyclo)alkyl(meth)acrylates with 4 or more carbon atoms in the (cyclo)alkyl group, and(b) the hydrophilic monomers are selected from the group of (meth)acrylic acid, (meth)acrylamide, (meth)acrylonitrile, optionally substituted; unsaturated monomers containing a sulphonic acid salt group; hydroxyalkyl(meth)acrylates; and, optionally, unsaturated monomers containing nonionic groups such as C1-C4 alkoxy polyalkylene oxide groups, wherein the molar ratio of unsaturated carboxylic acid groups to unsaturated sulphonic acid groups is between 1:1 and 4:1, the molar ratio of components (a) to components (b) is between 1:2 and 3:1, the COOH value is between 20 and 80, and the SO3H value is between 10 and 40, and the carboxylic acid groups are at least partly neutralised, a coating composition comprising such a binder composition, a process for the production of coating compositions consisting of said aqueous binder composition and, optionally, auxiliaries and additives known from lacquer technology, and a cross-linked coated substrate prepared by applying such a coating composition. |