Claims
- 1. A method of coating an electrically conductive article with the film forming resin using cathodic electrodeposition comprising:
- (1) forming a polyepoxide amine adduct;
- (2) forming a blocked crosslinker by bringing into contact tetramethyl xylene diisocyanate and a polyol under conditions that will cause a reaction and then totally blocking the reaction product with an oxime;
- (3) mixing said polyepoxide amine adduct with the blocked crosslinker;
- (4) adding acid and water to the mixture of the epoxy amine adduct and the crosslinker thereby forming a principal emulsion;
- (5) mixing the principal emulsion with the appropriate amount of water and pigment paste to form an electrocoat bath;
- (6) immersing the article in the electrocoat bath; and
- (7) passing a direct current across the article.
- 2. A resin composition for use as the film forming component in a cathodic electrodeposition process, comprising the reaction product of (A) a polyepoxide amine addust and (B) a cross-linking agent, said crosslinking agent being formed by brining into contact tetramethyl xylene diisocyanate and a polyol under conditions that will cause a reaction and then totally blocking the reaction product with an oxime, wherein the resin composition can be cured at temperatures below 275.degree. F.
- 3. The resin product of claim 2 wherein said polyol is trimethylolpropane and the ratio of trimethylolpropane to tetramethyl xylene diisocyanate is about 1:3.
- 4. The resin composition of claim 2 in which said polyepoxide amine addjuct is formed by mixing a polyepoxide with a secondary amine having primary hydroxyl groups at appropriate reaction conditions.
- 5. The resin composition of claim 4 in which said secondary amine having primary hydroxyl groups is selected from the group consisting of methyl ethanol amine or diethanol amine.
- 6. The resin composition of claim 4 in which said polyepoxide amine adduct is a polymer having an average of about two epoxy groups per molecule.
- 7. The resin composition of claim 6 in which said polyepoxides are polyglycidyl ethers of polyhydric phenols.
- 8. The resin composition of claim 2 in which said oxime blocking agent is selected from the group consisting of acetone oxime, methyl ethyl ketoxime, methyl amyl ketoxime, or methyl isobutyl ketoxime.
CROSS REFERENCE TO RELATED APPLICATIONS
This application is a continuation of application Ser. No. 07/275,357 filed on Nov. 23, 1988 now U.S. Pat. No. 4,900,415.
US Referenced Citations (17)
Continuations (1)
|
Number |
Date |
Country |
Parent |
275357 |
Nov 1988 |
|