Low VOC anionic electrodepositable coating composition

Patent metadata

Field	Value
Publication number	US-10370545-B2
Application number	US-201715708177-A
Country	US
Kind code	B2
Filing date	Sep 19, 2017
Priority date	Sep 19, 2017
Publication date	Aug 6, 2019
Grant date	Aug 6, 2019

Abstract

The present invention is directed to an electrodepositable coating composition comprising a main vehicle comprising a phosphatized epoxy resin, a plasticizer, and a curing agent, wherein the main vehicle comprises a low-VOC main vehicle. The present invention is also directed to coatings and coated substrates.

First claim

We claim:

1. An electrodepositable coating composition comprising a main vehicle comprising:
a phosphatized epoxy resin, wherein the phosphatized epoxy resin comprises a reaction product of reactants comprising:
an epoxy-functional polymerization product comprising the residue of:
a polyepoxide;
a polyphenol; and
a mono-functional acid and/or a mono-functional alcohol, wherein the ratio of epoxide functional groups from the polyepoxide to hydroxyl groups from the mono functional alcohol and/or acid groups from the mono-functional acid is from 8.1:1 to 19:1; and

a source of phosphoric acid, a source of phosphonic acid, or combinations thereof;

a plasticizer; and
a curing agent;
wherein the main vehicle comprises no more than 1.00 lb/gallon of volatile organic content.

2. The electrodepositable coating composition of claim 1 , wherein the reaction for forming the reaction product is performed in a solvent system comprising the plasticizer, and the solvent system comprises no more than 50% by weight of volatile organic solvent, based on the total weight of the solvent system.

3. The electrodepositable coating composition of claim 2 , wherein the phosphatized epoxy resin further comprises a reaction residue of the plasticizer.

4. The electrodepositable coating composition of claim 3 , wherein the plasticizer has a number average molecular weight of at least 200 g/mol.

5. The electrodepositable coating composition of claim 1 , wherein the mono-functional acid comprises benzoic acid.

6. The electrodepositable coating composition of claim 1 , wherein the mono-functional alcohol comprises a phenol.

7. The electrodepositable coating composition of claim 6 , wherein the phenol comprises nonyl phenol, dodecyl phenol or combinations thereof.

8. The electrodepositable coating composition of claim 1 , wherein the phosphatized epoxy resin has a molecular weight of 22,000 g/mol to 40,000 g/mol, as measured by gel permeation chromatography using polystyrene standards.

9. The electrodepositable coating composition of claim 1 , wherein the plasticizer comprises a polyethylene glycol ester and/or a polypropylene glycol ester.

10. The electrodepositable coating composition of claim 9 , wherein the polyethylene glycol ester comprises polyethylene glycol monolaurate.

11. The electrodepositable coating composition of claim 9 , wherein the polyethylene glycol ester has a molecular weight of 200 g/mol to 1,500 g/mol, as measured by gel permeation chromatography using polystyrene standards.

12. The electrodepositable coating composition of claim 1 , wherein the plasticizer has a boiling point of greater than 250° C.

13. The electrodepositable coating composition of claim 1 , wherein the ratio of phosphatized epoxy resin solids to volatile organic content is 7:1 to 25:1.

14. The electrodepositable coating composition of claim 1 , wherein the coating composition comprises 10% to 40% by weight of the plasticizer, based on the total weight of the resin solids.

15. The electrodepositable coating composition of claim 1 , wherein a coating applied by electrodepositing the coating composition has a dry film thickness of at least 38.1 microns.

16. The electrodepositable coating composition of claim 1 further comprising a pigment paste.

17. The electrodepositable coating composition of claim 1 , wherein a coating applied by electrodepositing the coating composition has dry film-thickness of at least 50 microns.

18. The electrodepositable coating composition of claim 1 , wherein a coating applied by electrodepositing the coating composition has a gloss retention of at least 60% after 3 months UV exposure as measured according to the UV Durability Test.

19. A coating formed by at least partially curing the electrodepositable coating composition of claim 1 .

20. A substrate coated with the electrodepositable coating composition of claim 1 in an at least partially cured state.

21. The substrate of claim 20 , wherein the electrodepositable coating layer has a dry film-thickness of at least 50 microns.

22. The electrodepositable coating composition of claim 1 , wherein the electrodepositable coating composition is an anionic electrodepositable coating composition.

Assignees

• Ppg Ind Ohio Inc

Inventors

• Lee Se Ryeon
• Follet Mark L

Classifications

• C09D5/4484

  Anodic paints (C09D5/4403 - C09D5/4476 take precedence) · CPC title

• C09D5/4434 Primary

  characterised by the nature of the epoxy binder · CPC title

• C25D9/02

  with organic materials · CPC title

• B32B15/092

  comprising epoxy resins · CPC title

• C25D13/04

  with organic material · CPC title