Protective layer for painted surfaces

摘要

An aqueous dispersion comprising a high molar mass polyurethane A and additives B, wherein the polyurethane has a number-average molar mass of at least 10 kg/mol and a weight-average molar mass of at least 20 kg/mol and wherein the additives B contain mercaptan groups, hydrazide groups and/or N-alkylamide groups, their preparation, and their use as a surface protection coating, especially for motor vehicles.