Abstract: Cationic heat-hardenable binders comprising polymers containing amine groups and a crosslinking component which is film-forming with the amine group containing polymer through transesterification at elevated temperatures are described. The binders which are water-dilutable upon protonization of the amine groups comprise(a) 60 to 95% by weight of a polymer having a hydroxyl value of from 40 to 450 mg KOH/g and an amine value of from 20 to 150 mg KOH/g, water-soluble or water-dilutable upon protonation of the basic groups, and(b) 5 to 40% by weight of a cross-linking component of the general formula ##STR1## n having a value of from 1 through 5, R.sub.1 being the moiety of a monoalcohol having from 1 to 8 C-atoms or of a polyol or of a polyamine or of a polyepoxy compound or of a polyisocyanate remaining after reaction with one or more carboxylic acid groups, andR.sub.2 being a straight chain or branched alkyl radical with from 1 to 8 C-atoms.