Überzugsmittel und deren Verwendung, insbesondere bei der Herstellung transparenter und pigmentierter Deckschichten

摘要

The invention relates to coating compositions which are suitable for the production of pigmented or transparent top coats, based on hydroxy-functional (meth)acrylic copolymers, aliphatic and/or cycloaliphatic polyisocyanates, solvents and optionally additives and pigments which are conventional in coating compositions (paints, enamels, varnishes, lacquers). They are free from epoxy resins and nitrocellulose and contain, as binder (vehicle), A) one or more hydroxyl-containing (meth)acrylic copolymers built up from a1) 47 - 53% by weight of one or more aromatic vinyl compounds, a2) 28 - 33% by weight of one or more hydroxyalkyl methacrylates, a3) 14 - 19% by weight of one or more alkyl (meth)acrylates, and a4) 0.5 - 2% by weight of acrylic acid and/or methacrylic acid, having a hydroxyl number of 120 - 160 mg of KOH/g, an acid number of from 5 to 15 mg of KOH/g, a weight average molecular weight of from 10,000 to 20,000 and a glass transition temperature of from +40 DEG C to +60 DEG C, and B) an aliphatic and/or cycloaliphatic polyisocyanate or a mixture of such polyisocyanates in such an amount that from 0.5 to 2.0 isocyanate groups are present per hydroxyl group from component A).