Process for improving the corrosion resistance of a metal surface

• Main Authors: YANAGI MUTSUMI, HONDA TAKUMI
• Format: Patent
• Language: English
• Published: 28.05.2002
• Edition: 7
• Subjects: ADHESIVES; APPLYING LIQUIDS OR OTHER FLUENT MATERIALS TO SURFACES, IN GENERAL; CHEMICAL PAINT OR INK REMOVERS; CHEMISTRY; COATING COMPOSITIONS, e.g. PAINTS, VARNISHES ORLACQUERS; CORRECTING FLUIDS; DYES; FILLING PASTES; INKS; METALLURGY; MISCELLANEOUS APPLICATIONS OF MATERIALS; MISCELLANEOUS COMPOSITIONS; NATURAL RESINS; PAINTS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; PERFORMING OPERATIONS; POLISHES; PROCESSES FOR APPLYING LIQUIDS OR OTHER FLUENT MATERIALS TOSURFACES, IN GENERAL; SPRAYING OR ATOMISING IN GENERAL; TRANSPORTING; USE OF MATERIALS THEREFOR; WOODSTAINS

A resin coating is formed on a metal surface using an aqueous autodepositing resin composition that contains oxidizing agent, acid, and carboxyl-functional and/or hydroxyl-functional water-dispersible or water-soluble resin and, optionally, metal ions; the resulting coating, while still in its uncured condition, is subject to post-treatment with an aqueous solution containing from 0.5 to 5.0 g/L of amine and from 10 to 100 g/L (solids) of water-soluble amino resin molecules that bear at least two alkoxymethylamino, methylolamino, and/or imino groups; and the coating is then dried and cured. This provides a highly anticorrosive coating on the metal, and contrary to an analogous process in which the post-treatment solution contains amino resin but not amine, the post-treatment solution remains stable and provides continuing high quality coating performance even after a considerable amount of metal surface per unit volume of post-treatment solution has been processed.