| abstract |
Cathodically depositable paint binders, water-soluble upon neutralization with acids, and the method of preparing the paint binders based on amine-epoxy adducts which crosslink at elevated temperature through polyurethane formation are described. The paint binders are prepared by reacting per mole of expoxide groups of a polymer having an epoxy equivalent of between about 180 and 1500 from about 3 to 70 mole percent of a polyisocyanate adduct having substantially no free NCO content and carrying per molecule at least one carboxyl group. Basic functionality is provided by reacting the epoxy-containing polymer, before or after reaction with the polyisocyanate adduct, with secondary aliphatic amines and/or alkanol amines. The binders, in addition to providing stable aqueous solutions when neutralized with an inorganic or organic acid, have good resistance to corrosion and solvents. |