Method and composition for treating metal surfaces

摘要

A method and composition for coating a metal for use in connection with improving corrosion resistance and paint adhesion. The composition is a non-corrosive ester cross-linked polymer system having a plurality of carboxylic functional groups and a plurality of hydroxyl groups. The polymer system may be a bifunctional copolymer or the reaction product of a first polymer having a plurality of carboxylic functional groups (e.g. polyacrylic acid or polymethylvinylmaleic anhydride), and a second polymer having a plurality of hydroxyl groups (e.g. polyvinyl alcohol). The resulting reaction product of these two polymers is a cross-linked polymeric blend. A compound of a Group IV-B element may be added to this polymer blend to increase the degree of cross-linking and improve paint adhesion and corrosion resistance. Such a Group IV-B compound may be an acid such as fluozirconic acid, fluotitanic acid or fluchafnic acid, or a salt such as ammonium zirconium carbonate. The method for improving corrosion resistance and paint adhesion of a metal surface includes contacting the metal surface with a composition of the present invention and drying the composition in place. Prior to contacting the metal surface with such a composition, the metal surface may be cleaned and rinsed.