Process for electrophoretic deposition of polymer

• US 3,926,760 A
• Filed: 09/28/1973
• Issued: 12/16/1975
• Est. Priority Date: 09/28/1973
• Status: Expired due to Term

• Current Assignee: James S. Allen, John D. Craig Jr
• Original Assignee: James S. Allen, John D. Craig Jr
• Inventors: Allen, James S., Craig, John D. Jr.
• Primary Examiner(s): Williams, Howard S.
• Application Number:
  US05/403,264
• Time in Patent Office: 809 Days
• Field of Search: 204/181
• US Class Current: 204/477
• CPC Class Codes: C09D 5/44 for electrophoretic applications processes for coating by electrophoresis C25D13/00

Abstract

An improved process for electrophoretically coating polymer on an electrode comprising maintaining the electrode that is being coated with polymer at a temperature at least above that of the continuous phase for a time that is sufficient to produce a polymer film coating the electrode, that after baking at a temperature and for a time that is sufficient to harden the film, has a greater resistivity than a film that is coated under the same conditions with the exception that an elevated temperature is not maintained.

Claims

1. HAS A GLASS TRANSITION TEMPERATURE OF AT LEAST 25*C.,

2. having such solvency that it will at least swell the polymer described in (a), and

3. IS SELECTED FROM THE GROUP CONSISTING ESSENTIALLY OF POLYMER FORMED FROM UNSATURATED MONOMERS, POLYESTERS, POLYURETHANES, POLYAMIDES POLYESTERIMIDES, POLYAMIC ACIDS, POLYAMIDE-IMIDES EPOXIES AND MIXTURES OF THE FOREGOING AND

4. has a molecular weight of at least about 100,100, b. using a continuous phase comprising water and at least one organic liquid, said organic liquid

5. The process of claim 1 wherein the composition used in the electrophoretic process is agitated sufficiently during the maintenance of the elevated temperature that a substantially uniform temperature is maintained throughout such composition.

6. The process of claim 1 wherein the organic liquid is a mixture of 4-31% ethylene glycol monoethyl ether, 21-51% ethylene glycol monobutyl ether acetate, 21-51% propylene glycol and 4-10% xylene, the foregoing percentages being by weight based on the total weight of all of the organic liquids.

7. The process of claim 1 wherein prior to electrodeposition the electrode is cleaned to remove any contaminants.

8. The process of claim 7 wherein the cleaning is done by immersion of the electrode in a bath of organic liquid that has ultra-sonic sound waves acting upon it.

9. The process of claim 1 wherein during the electrophoretic deposition of polymer the electrode is maintained at a temperature of at least about 1*C. above that of the temperature of the electrophoretic bath for a duration of about 1 second to 5 hours.

10. The process of claim 9 wherein the electrode is maintained at a temperature of at least about 2*C. above that of the electrophoretic bath.

11. The process of claim 10 wherein the electrode is wire coated with a film of polymer that is part of a stator of an electric motor.

12. The process of claim 10 wherein prior to electrodeposition the electrode is cleaned to remove any contaminants.

13. The process of claim 1 wherein the polymer is formed from unsaturated monomers.

14. The process of claim 13 wherein the polymer is formed froM 0.14-15.0% by weight, based on the total weight of the polymer, of a-olefinic monocarboxylic acid.

15. The process of claim 14 containing thermosetting resin selected from the group consisting of condensate of phenol compound with aldehyde compound, melamine with aldehyde compound, urea with aldehyde compound or benzoquanamine with aldehyde compound in an amount of about 0.5-80% by weight based on the combined weight of the thermosetting resin and polymer.

16. The process of claim 15 wherein during the electrophoretic deposition of polymer the electrode is maintained at a temperature of at least about 1*C. above that of the electrophoretic bath for a duration of about 1 second to about 5 hours.

17. The process of claim 16 wherein the electrode is metal that has been coated previously with a film of polymer.

18. The process of claim 13 wherein the polymer is formed from (A) 10-80% of at least one monomer selected from the group consisting essentially of acrylonitrile and methacrylonitrile, (B) 0.1-15% of at least one a-olefinic monocarboxylic acid and (C) 9.5-89.9% of at least one monomer that is an ester of an a-olefinic mono-carboxylic acid with a saturated aliphatic monohydric alcohol of 1 to 8 carbon atoms, the foregoing percentages being by weight based on the total weight of the polymer.

19. The process of claim 18 wherein (A) is 30-70%, (B) is 2-15%, and (C) is 29-68%.

20. The process of claim 18 wherein (A) is 40-65%, (B) is 2-10%, and (C) is 33-58%.

21. The process of claim 18 wherein the composition used in the electrophoretic process is agitated sufficiently during the maintenance of the elevated temperature that a substantially uniform temperature is maintained throughout such composition.

22. The process of claim 18 containing thermosetting resin selected from the group consisting of condensate of phenol compound with aldehyde compound or benzoguanamine with aldehyde compound in an amount of about 0.5-80% by weight based on the combined weight of the thermosetting resin and polymer.

23. The process of claim 22 wherein the composition used in the electrophoretic process is agitated sufficiently during the maintenance of the elevated temperature that a substantially uniform temperature is maintained throughout such composition.

24. The process of claim 23 wherein during the electrophoretic deposition of polymer the electrode is maintained at a temperature of at least about 1*C. above that of the electrophoretic bath for a duration of about 1 second to about 5 hours and the polymer has a molecular weight of about 100, 000.