Patent DE-102007010614-A1 (DE)
Title: Aqueous copolymer-dispersion, useful e.g. to prepare ground coat, comprises a polyester portion, made from a compound comprising e.g. polyol and a polyacrylate portion, obtained from monomer comprising e.g. (meth)acrylic acid ester
Inventor: GERTZMANN ROLF
IPC: C08L67/02
Filed: 2007-03-02
Abstract: Aqueous copolymer-dispersion (I) comprises a polyester portion, made from a compound comprising (a) di-, tri- or tetracarboxylic acid or their anhydrides, (b) di- and/or polyol, (c) hydroxycarboxylic acid, lactone, aminoalcohol and/or aminocarboxylic acid, (d) mono- or dicarboxylic acid and/or di- and/or polyol or (e) monocarboxylic acid and/or monoalcohol and a polyacrylate portion, obtained from monomer comprising (f) (meth)acrylic acid ester and/or vinyl aromate, (g) vinyl monomer or (meth)acrylic acid ester, (h) acid groups containing monomer or (i) a compound different from (f)-(h). Aqueous copolymer-dispersion (I) comprises a polyester portion, made from a compound comprising (a) saturated, aliphatic and/or aromatic di-, tri- or tetracarboxylic acid or their anhydrides, (b) di- and/or polyol, (c) hydroxycarboxylic acid, lactone, aminoalcohol and/or aminocarboxylic acid, (d) (cyclo)aliphatic, olefinically unsaturated mono- or dicarboxylic acid and/or unsaturated di- and/or polyol or (e) monocarboxylic acid and/or monoalcohol and a polyacrylate portion, obtained from monomer comprising (f) hydroxyl-group free (meth)acrylic acid ester and/or vinyl aromate, (g) hydroxyfunctional vinyl monomer or hydroxyfunctional (meth)acrylic acid ester, (h) acid groups containing monomer suitable for radical copolymerization or (i) a compound different from the components (f)-(h), which is a monomer suitable for radical copolymerization, where the polyester portion exhibits an hydroxyl number of 180-300 mg potassium hydroxide (KOH)/g substance and an acid number of 0.5 and 30 mg of KOH/g, the polyacrylate portion exhibits an hydroxyl number of 10-180 mg KOH/g substance and an acid number of 10-100 mg of KOH/g and the copolymer exhibits an hydroxyl-number, which is less than that of the polyester portion and greater than 10 mg KOH/g. Independent claims are included for: (1) preparing (I) comprising providing the polyester in a solvent mixable with water, subsequently adding a hydroxy functional monomer mixture (a1) from (f), (g) and optionally (i) to the polyester and the monomer mixture exhibits a hydroxyl number of 12-350 mg KOH/g solid material and an acid number of 0-50 mg KOH/g solid material in a first step, and adding other monomer mixture (a2) of monomer from (f), (g), (h) and optionally (i) and the monomer mixture exhibits a hydroxyl number of 10-350 mg KOH/g solid material and an acid number of 50-300 mg KOH/g solid material, and subsequently dispersing the copolymer in water in a second step, where the monomer quantity in the first and second step is selected such that the mass ratio of (a1) to (a2) amounts to 10:1-1:2; (2) an aqueous coating agent comprising (I) and at least a reactive cross linker with hydroxyl-groups; and (3) a two-component varnish comprising (I) and at least a cross linker, which is polyisocyanate.