BigPatents India

The present invention relates to a coating composition comprising; A) at least one polyester oligomer prepared from reactants comprising a) 20 60 wt. % of at least one polyol, b) 5 30 wt. % of at least one polycarboxylic acid selected from the group of cyclic polycarboxylic acids, the esters or the anhydrides thereof, wherein the carboxyl groups are separated by 3 carbon atoms or less, and from the group of .-saturated acyclic polycarboxylic acids, the esters or the anhydrides thereof, and c) 20 60 wt % of at least one monocarboxylic acid, the sum of the wt. % indicated for the reactants (a), (b), and (c) always being 100 wt. %, and the oligomer being a low-viscosity oligomer having a weight average molecular weight Mw of less than 5,000, and a hydroxyl number in the range of about 200 to about 400 mg KOH/g oligomer, and B) at least one polyisocyanate. Also covered is the use of the coating compositions of the invention in the field of finishing and refinishing of automobiles and large transportation vehicles. The coating compositions are particularly useful as primers and topcoats in multi-layered coating systems.