Polyamines and their use in aqueous coating compositions

An aqueous, two-component coating composition containing as binder

• A) a polyamine which is the reaction product of
• a) an unsaturated oligoester containing an average of 2 to 4 double bonds per molecule and
• b) optionally another unsaturated compound which is suitable as a Michael addition acceptor and which contains an average of 1 to 4 double bonds per molecule, with
• c) a (cyclo)aliphatic diamine which contains two primary amino groups, and
• d) optionally another amino-functional compound which is suitable as a Michael addition donor and
• B) a water dispersible polyisocyanate having
• a) an average NCO functionality of 1.8 to 4.2,
• b) a content of aliphatically and/or cycloaliphatically bound isocyanate groups of 12 to 21.5% by weight, based on the weight of polyisocyanate B) and
• c) a content of ethylene oxide units present within polyether chains of 2 to 20% by weight, based on the weight of polyisocyanate B).