| abstract |
A process and coating agent are disclosed for producing a decorative multiple-layer varnish coating on a substrate. The process involves applying a foundation layer of varnish, which is then coated with a layer of transparent varnish. The foundation varnish is an aqueous, bathotonic foundation varnish containing an aqueous polyurethane resin dispersion as a binder. The polyurethane resin in question has a number average molecular weight (Mn) of 2500-12,0000, a proportion of lateral and/or terminal silicon-bonded hydroxyl- and/or R'O groups of 10-400 mMol for each 100 g of solid resin, wherein R' is C1-8 alkyl or C(O)R''' and R''' is C1-10 alkyl. It will have a hydroxyl number of 0-150, hydroxyl groups bonded with silicon not counting towards the OH number, and a proportion of ionic groups, groups which can be converted to ionic groups and/or hydrophilic groups of 5-200 milli-Equivalents for 100 g of solid resin. |