Two-pack polyurethane paint for backing films

Aqueous two-component polyurethane lacquer comprising

• A) at least one hydroxy-functional polyester-polyurethane dispersion comprising as structural components
• a1) linear or branched, hydroxy-functional polyesters,
• a2) linear, hydroxy-functional polycarbonates,
• a3) at least one ionic or potentially ionic compound with at least one acid group and with at least one group that is reactive towards isocyanate groups,
• a4) at least one (cyclo)aliphatic diisocyanate and also
• a5) low-molecular hydroxy-functional and/or amino-functional compounds,
• and also
• B) at least one polyisocyanate cross-linker, wherein the cross-linking ratio of isocyanate groups from B) to hydroxy groups from A) is from 1.0:1 to 1.6:1.