Patent ID: 6509408
Filing Date: 2003-01-21
Classification: C08F,C08G,C08L,C09D

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, wherein the partially unsaturated hydroxy-functional polyester has a hydroxyl value of 50 to 350, a COOH value of at most 10 mg KOH/g, and a number average molecular weight, optionally after chain extension with a polyisocyanate, of from 400 to 3,000, and is obtained by reaction of a mixture of polycarboxylic and, optionally, monocarboxylic acids, at least 50 mole % of such poly- and/or monocarboxylic acids are aliphatic acids with 6-12 carbon atoms, with one or more (cyclo)aliphatic alcohols comprising an aliphatic and/or a cycloaliphatic diol, wherein 0.5-6 mole % of the acids and/or alcohols are ethylenically unsaturated, and, optionally, a mono- and/or bisepoxide, and/or a tri- or higher-functional polyacid and/or polyalcohol, and the 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.