Low-solvent, thermosetting reactive polyurethane coating composition, a process for its production and its use in direct and reverse coating processes

摘要

The invention relates to low-solvent, thermosetting reactive polyurethane coating compositions which are particularly resistant to light, oxidation and hydrolysis, do not crystallize or harden and comprise the following components: (A) a ketoxime-blocked NCO-prepolymer of 1. 1 mole of 2- to 4-functional, relatively high molecular weight polyhydroxyl compounds comprising a polyester polycarbonate based on ester glycols of epsilon -caprolactone and 1,6-hexane diol; 2. about 0.1 to 1.2 moles of low molecular weight polyols containing bis-carbazinic ester polyols corresponding to the following general formula <IMAGE> in which R is a straight-chain and/or branched C1-C5-alkylene or hydroxyl-substituted alkylene radical, and low molecular weight diols and triols preferably containing tertiary amino groups, and 3. aliphatic and/or cycloaliphatic diisocyanates in an NCO/OH ratio of from about 1.5:1 to 6:1 and 4. ketoximes; (B) aliphatic and/or cycloaliphatic polyamines containing at least two primary amino groups and (C) up to about 40% by weight of organic solvents. The invention also relates to a process for producing the low-solvent reactive coating compositions and to their use for coating substrates by the direct, reverse and/or matrix coating process.