Metal treatment – Process of modifying or maintaining internal physical... – Processes of coating utilizing a reactive composition which...
Patent
1998-01-26
2000-03-07
Simmons, David A.
Metal treatment
Process of modifying or maintaining internal physical...
Processes of coating utilizing a reactive composition which...
148245, 148251, 148261, 148262, 148283, 4273881, 4273884, C23C 800
Patent
active
060334924
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to a method for coating a metal surface, for example a metal such as iron, zinc, iron alloys and zinc alloys, and the like, by autodeposition to form a predominantly organic coating on the surface of the metal, more particularly a coating which, besides having outstanding corrosion resistance and adhesion, also has a good appearance without any unevenness in gloss.
BACKGROUND ART
Coating compositions which enable the formation of a resin coating on a metal surface by bringing said metal surface into contact with an acidic composition which includes an organic film-forming resin are known as "autodepositing" or "autodeposition" compositions and are usually water-based. Such compositions are disclosed in Japanese Patent S47-17630, Japanese Examined Patent S52-21006, Japanese Examined Patent S54-13435 and Japanese Unexamined Laid-Open Patent Application S61-168673.
The defining characteristic of autodepositing waterbased coating compositions is that by contacting a suitable metal material having a clean surface with the coating composition, a resin coating film which increases in thickness or weight as immersion time increases forms spontaneously as a result of chemical reaction between the metal and the coating composition. (Metal ions dissolved from the metal surface are believe to interact with the resin particles and to be deposited together with them onto the metal surface.) Thus, a resin coating film can be beneficially formed on said metal surface without the need for external electromotive force, as is required in electrodeposition. However, in some cases the corrosion resistance and adhesion of an autodeposited resin coating film is not entirely satisfactory, and various means have been disclosed for improving these properties. Such means include chemical treatments of wet autodeposited coating films before they are dried. (Such chemical treatments are known by various names in the art; the most common such name is probably "final rinse", which is well-established but often a misnomer, because there may be other subsequent water rinses. Other names are "after-treatment", "post-treatment", "reaction rinse", "chemical rinse", and the one preferred herein, "modifying rinse".) The following citations exemplify such treatments.
In Japanese Examined Patent S53-15093 and U.S. Pat. No. 3,795,546 it is disclosed that by bringing a coated object into contact with an aqueous solution containing a hexavalent chromium compound and polyacrylate after immersion in an autodepositing aqueous coating composition and before hot drying the coated resin film, the corrosion resistance of the coating film after drying is raised.
In Japanese Unexamined Laid-Open Patent Application S51-30245 a method is disclosed for preventing poor appearance, such as blistering and cracking and the like, of autodeposited resin coating films after hot drying, by bringing the said resin coating film before drying into contact with an aqueous solution containing from 10-100 grams per liter (hereinafter usually abbreviated as "g/L") of a water-soluble solvent such as an alcohol, ketone, alcohol ester, ketone ester, ketone ether, or ester ether.
In Japanese Unexamined Laid-Open Patent Application S52-68240 a method is disclosed for raising the corrosion resistance of an autodeposited resin coating film formed on a coated object after hot drying by bringing said resin coating film before drying into contact with an aqueous solution or aqueous dispersion containing from 5-100 g/L in total of one or more substances selected from the group consisting of nitrogen-containing organic compounds such as amines, carboxylic acid amine salts, amino acids, melamine and amides, for example.
In Japanese Unexamined Laid-Open Patent Application H3-505841 a method is disclosed for raising the post-drying adhesion and corrosion resistance of an autodeposited resin coating film formed on a coated object by bringing said resin coating film, before hot drying, into contact with an aqueous solution of an alkaline subs
REFERENCES:
patent: 3585084 (1971-06-01), Steinbrecher et al.
patent: 3795546 (1974-03-01), Hall et al.
patent: 4874673 (1989-10-01), Donovan et al.
patent: 5164234 (1992-11-01), Siebert
patent: 5342694 (1994-08-01), Ahmed et al.
Hatano Norifumi
Hirota Mutsumi
Honda Takumi
Henkel Corporation
Jaeschke Wayne C.
Koehler Robert R.
Simmons David A.
Szoke Ernest G.
LandOfFree
Composition and process for autodeposition with modifying rinse does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Composition and process for autodeposition with modifying rinse , we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Composition and process for autodeposition with modifying rinse will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-359070