| abstract |
A process for painting plastic substrates with aq. paints (I) contg. (A) polyester-polyol(s) with OH no. at least 250, acid no. below 5 and Mn 500-1100, (B) polyether-polyol(s) with Mn 350-550 obtd. by reaction of 1 mol. polyol contg. at least 3 OH gps. with 4-8 mols. propylene oxide (PO) and/or ethylene oxide (EO), (C) amino resin(s), (D) OH gp.-contg. polyacrylate resin(s) with OH no. 20-200, stabilised with 4-20wt.% poly-EO and/or poly-PO and/or poly-EO-PO gps., and with particle size 40-1000nm, and (E) acid hardening catalyst(s). Plastic substrate is polyamide (PA) or polyurethane (PU), and (I) are used as 2-component paints; (A) is obtd. by esterification of polycarboxylic acids with polyols, using reactants contg. not more than 15 mol.% cycloaliphatic or aromatic gps.. USE/ADVANTAGE - (I) are useful for painting or priming plastic substrates, esp. PA or PU (claimed). The invention provides water-based paints with improved adhesion to plastic substrates and increased resistance to moisture, esp. for painting plastic motor body part |