Allophanate group-containing polyisocyanates improved compatibility with aldimines

The present invention relates to coating compositions containing a) aldimines and b) polyisocyanates which i) contain 2 to 35% by weight of allophanate groups, based on the weight of the polyisocyanates, ii) have a viscosity of less than 3000 mpa.s at 25 DEG C. when measured at a solids content of 100%, iii) are based on the reaction products of aliphatic polyisocyanates with 1) 10 to 90 mole percent of monohydroxy compounds and 2) 10 to 90 mole percent of polyhydric alcohols, wherein the mole percentages of 1) and 2) add up to 100, and the percentages are based on the total moles of monohydroxy compounds 1) and polyhydric alcohols 2) and iv) contain less than 10 mole percent of urethane groups, based on the total moles of urethane groups obtained from monohydroxy compounds 1) and polyhydric alcohols 2). The present invention also relates to these polyisocyanates containing allophanate groups and to polyisocyanate mixtures containing these polyisocyanates and polyisocyanate adducts containing isocyanurate, uretdione, biuret and/or urethane groups.