Epoxy resin emulsions for electrocoating

Patent metadata

Field	Value
Publication number	US-11186734-B2
Application number	US-201916427869-A
Country	US
Kind code	B2
Filing date	May 31, 2019
Priority date	May 31, 2019
Publication date	Nov 30, 2021
Grant date	Nov 30, 2021

Abstract

An epoxy resin emulsion includes a continuous phase including an aqueous carrier and an acid. The emulsion also includes a dispersed phase including an epoxy resin. The epoxy resin is the reaction product of an amine compound and a first epoxy reactant. The first epoxy reactant itself includes the reaction product of (1) an aromatic diol monomer, (2) a di-glycidyl ether of Bisphenol A and/or a di-glycidyl ether of catechol, and (3) a C8-C18 alkyl phenolic end-capping agent. The (1) aromatic diol monomer has the structure:In this structure, each of R1-R4 is independently a hydrogen atom, a C1-C8 alkyl group, a C3-C8 cycloalkyl group, an aryl group, an aralkyl group, a halide group, a cyano group, a nitro group, a blocked isocyanate group, or a C1-C8 alkyloxy group or wherein any two or more of R1-R4 may be a fused ring.

First claim

What is claimed is:

1. An electrocoating composition comprising:
A. an epoxy resin emulsion that is free of sulfamic acid and consists essentially of:
(1) a continuous phase comprising water, lactic acid, methanesulfonic acid, and nitric acid; and
(2) a dispersed phase comprising an epoxy resin that is reaction product of:
(a) a liquid epoxy resin of diglycidyl ether of bisphenol A;
(b) catechol;
(c) dodecylphenol; and
(d) polypropylene glycol; and

B. a cross-linking resin that comprises the reaction product of methylene diphenyl diisocyanate and trimethylolpropane.

2. The electrocoating composition of claim 1 wherein said epoxy resin of said dispersed phase has a weight average molecular weight (Mw) of from about 1,000 to about 100,000 g/mol.

3. The electrocoating composition of claim 1 wherein said epoxy resin of said dispersed phase has a weight average molecular weight (Mw) of from about 5,000 to about 20,000 g/mol.

4. The electrocoating composition of claim 1 wherein said epoxy resin of said dispersed phase has a weight average molecular weight (Mw) of from about 5,000 to about 10,000 g/mol.

5. The electrocoating composition of claim 1 where-in epoxy resin emulsion consists essentially of said water, said acids, and said epoxy resin of said dispersed phase.

6. The electrocoating composition of claim 1 wherein
said water is present in an amount of about 53.5 wt %;
said lactic acid is present as a 56% solution in an amount of about 1.2 wt %;
said methane sulfonic acid is present as a 70% solution in an amount of about 0.7 wt %;
said liquid epoxy resin of diglycidyl ether of bisphenol A is utilized in an amount of about 15.1 wt %;
said catechol is utilized in an amount of about 2.7 wt %;
said dodecylphenol is utilized in an amount of about 0.8 wt %;
said polypropylene glycol has a weight average molecular weight of 900 g/mol and is utilized in an amount of about 3.7 wt %;
and
said cross-linking resin is present in an amount of about 18.3 wt %.

7. The electrocoating composition of claim 6 further comprising ethyltriphenyl phosphonium iodide, N,N-diethanolamine, aminopropyldiethanolamine, and a plasticizer additive.

8. The electrocoating composition of claim 7 wherein
said ethyltriphenyl phosphonium iodide is present in an amount of less than about 0.02 wt %;
said N,N-diethanolamine is present in an amount of about 1.7 wt %;
said aminopropyldiethanolamine is present in an amount of about 1 wt %; and
said plasticizer additive is present in an amount of about 0.8 wt %.

9. The electrocoating composition of claim 8 wherein the epoxy resin emulsion has a solids content of about 41.1%, and a particle size of about 105 nm.

10. The electrocoating composition of claim 9 wherein the epoxy resin of said dispersed phase has a weight average molecular weight of about 7566 g/mol.

11. The electrocoating composition of claim 7 wherein the epoxy resin emulsion has a solids content of about 41.1%, and a particle size of about 105 nm.

12. The electrocoating composition of claim 11 wherein the epoxy resin of said dispersed phase has a weight average molecular weight of about 7566 g/mol.

13. The electrocoating composition of claim 6 wherein the epoxy resin emulsion has a solids content of about 41.1%, and a particle size of about 105 nm.

14. The electrocoating composition of claim 13 wherein the epoxy resin of said dispersed phase has a weight average molecular weight of about 7566 g/mol.

15. The electrocoating composition of claim 1 further comprising ethyltriphenyl phosphonium iodide, N,N-diethanolamine, aminopropyldiethanolamine, and a plasticizer additive.

16. The electrocoating composition of claim 1 wherein the epoxy resin emulsion has a solids content of about 41.1%.

17. The electrocoating composition of claim 1 wherein the epoxy resin emulsion has a particle size of about 105 nm.

18. The electrocoating composition of claim 1 wherein the epoxy resin of said dispersed phase has a weight average molecular weight of about 7566 g/mol.

19. A coated substrate comprising:
an electrogalvanized substrate; and
a coating layer disposed on said electrogalvanized substrate, wherein the coating layer is formed from an electrocoating composition comprising:
A. an epoxy resin emulsion that is free of sulfamic acid and consists essentially of:
(1) a continuous phase comprising water, lactic acid, methanesulfonic acid, and nitric acid; and
(2) a dispersed phase comprising an epoxy resin that is reaction product of:
(a) a liquid epoxy resin of diglycidyl ether of bisphenol A;
(b) catechol;
(c) dodecylphenol; and
(d) polypropylene glycol; and

B. a cross-linking resin that comprises the reaction product of methylene diphenyl diisocyanate and trimethylolpropane,
wherein said epoxy resin that is the reaction product of (a)-(d) cures to form the coating layer, and
wherein the coating layer has a surface roughness Ra of less than 0.4 μm as measured using ISO 4287 (R) and that has an edge protection of less than 3 as measured using VDA 233-102 at 6 cycles.

20. The coated substrate of claim 19 ,
wherein, in the electrocoating composition,
said water is present in an amount of about 53.5 wt %;
said lactic acid is present as a 56% solution in an amount of about 1.2 wt %;
said methane sulfonic acid is present as a 70% solution in an amount of about 0.7 wt %;
said liquid epoxy resin of diglycidyl ether of bisphenol A is utilized in an amount of about 15.1 wt %;
said catechol is utilized in an amount of about 2.7 wt %;
said dodecylphenol is utilized in an amount of about 0.8 wt %;
said polypropylene glycol has a weight average molecular weight of 900 g/mol and is utilized in an amount of about 3.7 wt %; and
said cross-linking resin is present in an amount of about 18.3 wt %,

wherein the coating composition further comprises ethyltriphenyl phosphonium iodide, N,N-diethanolamine, aminopropyldiethanolamine, and a plasticizer additive, and
wherein
said ethyltriphenyl phosphonium iodide is present in an amount of less than about 0.02 wt %;
said N,N-diethanolamine is present in an amount of about 1.7 wt %;
said aminopropyldiethanolamine is present in an amount of about 1 wt %; and
said plasticizer additive is present in an amount of about 0.8 wt %.

Assignees

• Axalta Coating Systems Ip Co

Inventors

• Jin Xin
• Ren Chun

Classifications

• C09D5/4442

  Binder characterised by functional groups · CPC title

• C08K5/09

  Carboxylic acids; Metal salts thereof; Anhydrides thereof · CPC title

• C08G59/1444

  Monoalcohols · CPC title

• C08G59/066

  with chain extension or advancing agents · CPC title

• C09D5/08

  Anti-corrosive paints · CPC title