| abstract |
Aqueous coating agents for applying a multilayered enamel coating on motor vehicles are based on one or several binders, optional cross-linking agents, pigments and/or fillers, paint additives and/or solvents. As binders, these aqueous coating agents contain an aqueous dispersion based on polyurethane/polymer hybrids with an average numeric molar mass (Mn) from 8,000 to 1, 500,000, a weight ratio from polyurethane to polymer fraction from 0.05 : 1 to 50 : 1, a hydroxyl number from 0 to 150 mg KOH/g), relative to the solid resin (hydroxyl groups bound to silicium are not counted when calculating the OH number), an acid number from 1.5 to 40 mg KOH/g, relative to the solid resin, and a content from 0.5 to 150 mmol silicium per 100 g solid resin in the form of siloxane bridges (-Si-O-Si-) incorporated into the polyurethane fraction and/or in the form of silanol groups bonded to the polyurethane fraction. |