Coating compositions and process therefor

Process for producing thermosetting coating compositions from saturated polyesters containing hydroxy groups and aminoplast resins, characterized in that

• A. n mols of one or more compounds having two free or latent hydroxy groups are reacted with
• B. n +1 mols of a dicarboxylic acid which will not form an anhydride, to form a polyester AB carrying terminal carboxy groups,
• C. thereafter each mol of polyester AB is reacted with an amine alcohol of the general formula
• HO -- (CX.sub.2).sub.n -- NH.sub.2
• n being 2 or 3 and X is equal or different and stands for hydrogen, or an alkyl, aryl or hydroxy alkyl radical, the amount of AB to amine being equal to (e.sub.s - e.sub.p) M.sub.A wherein M.sub.A is the molecular weight of the amine alcohol;
• e.sub.s equals the number of carboxy equivalents in the polyester;
• and e.sub.p equals the number of hydroxy equivalents in the polyester, and not exceeding 2 mols amine alcohol per mol polyester AB, to provide a polyester containing terminal oxazoline groups,
• D. reacting ABC with an aldehyde in an amount sufficient to introduce sufficient hydroxyl groups at the carbon atoms alpha to the oxazoline group of ABC in order that ABC will undergo reaction with an aminoplast resin, and
• E. combining ABCD with 10 - 60 percent by weight of an aminoplast resin.