Water-based coating compositions and coating method using the same

摘要

A water-based thermosetting coating composition comprises a polyester resin having a number of pendant carboxyl groups and a crosslinker for the resin both dispersed in an aqueous medium containing a neutralizing base. The polyester resin contains as polyester-forming polyhydric alcohol reactants from 1 to 40 % by weight of the entire polyester-forming reactants of a polyalkadienediol or a hydrogenated products thereof and from 2 to 50 % by weight of the entire polyester-forming reactants of a 2,2-bis(hydroxymethyl)alkanoic acid. The coating composition is useful for forming a multilayer coating film on metallic substrates such as automobile bodies by applying the coating composition as an intermediate coating layer between an electrodeposition coating layer and a top coating layer.