Universal aqueous
coating compositions for
pretreating metal surfaces
Patent No. U.S. 6,805,756 B2
PPG Industries has received a patent for a process for pretreating a metal substrate comprising contacting the substrate with an aqueous composition. The aqueous composition is comprised of at least one hydroxy functional cyclic compound present in an amount of at least 500 ppm. The hydroxy functional cyclic compound selected from the group consisting of hydroxy phenolic compounds and heterocyclic nitrogen-containing compounds has hydroxy functionality; phosphate ions; at least one oxidizer-accelerator; at least one group IVB metal compound capable of converting to a metal oxide upon application to the metal substrate; at least one disaccharide; and water.