Co-cure process for autodeposition coating

Patent metadata

Field	Value
Publication number	US-9895717-B2
Application number	US-201313957892-A
Country	US
Kind code	B2
Filing date	Aug 2, 2013
Priority date	Jan 8, 2008
Publication date	Feb 20, 2018
Grant date	Feb 20, 2018

Abstract

A coated article comprising a metal surface, a first layer of an uncured autodeposition coating and a second uncured paint layer deposited sequentially on the surface without intermediate curing of the autodeposition coating, a process of co-curing said autodeposition coating and paint layer or layers, and a cured coated article having chemical bonds between the cured autodeposition coating layer and at least the cured paint layer immediately adjacent to the cured autodeposition coating layer.

First claim

What is claimed is:

1. A coated article comprising:
a steel surface having thereon a cured coating comprising:
a first layer comprising an autodeposition coating deposited directly on the steel surface, wherein polymers from the autodeposition coating consist of polymers and copolymers of acrylic, epoxy, polyurethane, phenol-formaldehyde condensation polymers, epoxy-acrylic hybrid polymer and mixtures thereof; and
a second layer comprising paint or adhesive, different from the first layer, deposited directly on the first layer wherein the first layer was dewatered prior to deposition of the second layer, the second layer deposited following the dewatering without intervening steps,

said cured coating comprising chemical bonds between the autodeposition coating and at least a portion of the second layer immediately adjacent to the autodeposition coating layer.

2. The coated article of claim 1 wherein said first and second layers are cross-linked to each other.

3. The coated article of claim 1 wherein said first and second layers are cross-linked to each other via COOH-epoxy reactions and/or OH—NCO urethane reactions.

4. The coated article of claim 1 wherein the first and second layers are co-cured such that the autodeposition coating undergoes a first cross-linking reaction and the second layer of paint is cured and/or undergoes a second cross-linking reaction.

5. The coated article of claim 4 wherein first and second cross-linking reactions are of different types.

6. The coated article of claim 4 wherein said first and second layers have been co-cured such that the first and second layers are chemically cross-linked to each other.

7. The coated article of claim 6 wherein the first layer comprises OH—NCO reaction products from the first cross-linking reaction, the second layer comprises COOH-epoxy reaction products from the second cross-linking reaction, and an interface of said first and second layers comprises interfacial reaction products from the cross-linking of the first and second layers to each other said interfacial reaction products comprising: reaction products of a reaction of NCO from the autodeposition coating with OH from COOH functional paint or adhesive; and/or reaction products of a reaction of an acid from the autodeposition coating with an epoxy from the paint.

8. The coated article of claim 1 wherein the second layer is a powder paint layer.

9. A coated article comprising:
at least one metal surface consisting of a steel surface having thereon a cured coating comprising:
a first layer comprising an autodeposition coating, wherein polymer molecules in said autodeposition coating are selected from the group consisting of acrylic, polyurethane, epoxy and epoxy-acrylic hybrid polymers, deposited directly on the steel surface by an electroless chemical reaction of the steel surface with an autodeposition coating bath directly contacting the steel surface; and
a second layer comprising paint or adhesive, different from the first layer, deposited directly on the first layer wherein the first layer was dewatered prior to deposition of the second layer, said deposition of the second layer following the dewatering without intervening steps,

said cured coating comprising chemical bonds between the autodeposition coating and at least a portion of the second layer immediately adjacent to the autodeposition coating layer.

10. The coated article of claim 9 wherein the second layer is a powder paint layer.

11. The coated article of claim 9 wherein the uncured autodeposition coating comprises an epoxy-acrylic hybrid polymer and the uncured paint layer is a COOH functional polyester paint.

12. The coated article of claim 11 wherein the COOH functional polyester paint comprises an isocyanurate or a hydroxyl alkyl amide.

13. The coated article of claim 11 wherein the COOH functional polyester paint comprises a triglycidyl isocyanurate.

14. The process coated article of claim 9 , wherein the metal surface consists of a cold rolled or hot rolled steel surface.

15. A process for treating an article comprising a substrate having at least one active metal surface comprising steps of:
a) contacting a substrate having at least one active metal surface consisting of steel with an autodeposition liquid composition wherein the autodeposition liquid composition directly contacts the active metal surface, the autodeposition liquid composition comprising components:
1) at least 1.0%, based on the autodeposition liquid composition, of a component of dissolved, dispersed, or both dissolved and dispersed film forming polymer molecules;
2) optionally at least one emulsifier;
3) at least one dissolved accelerator component selected from the group consisting of acids, oxidizing agents, and complexing agents that are not part of immediately previously recited components (1) or (2), this accelerator component being sufficient in strength and amount to impart to the total autodepositing liquid composition an oxidation-reduction potential that is at least 100 mV more oxidizing than a standard hydrogen electrode;
the pH of the autodeposition liquid composition being between about 1 and about 4, for a sufficient time and at a sufficient temperature to deposit an uncured autodeposition coating on said at least one active metal;
with the proviso that film forming polymer molecules are selected from the group consisting of polymers and copolymers of acrylic, epoxy, polyurethane, phenol-formaldehyde condensation polymers, epoxy-acrylic hybrid polymer and mixtures thereof;

b) rinsing with a rinse comprising water;
c) dewatering the uncured autodeposition coating at a temperature of at least 100° C. for a duration of heating selected such that the uncured autodeposition coating remains substantially uncross-linked;
d) following step c) without intervening steps, depositing an uncured paint layer directly on the uncured autodeposition coating; and
e) co-curing the uncured autodeposition coating and uncured paint layer;
wherein in step e) the uncured autodeposition coating and the uncured paint layer are co-cured to form on said at least one active metal surface a first layer of a cured autodeposition coating and a second layer of a cured paint, different from the first layer, such that the first and second layers have chemical bonds between the cured autodeposition coating and the cured paint at least immediately adjacent to the cured autodeposition coating.

16. The process of claim 15 wherein the first layer of a cured autodeposition coating and the second layer of a cured paint, different from the first layer, comprise at least one shared cross-linked polymer chain comprising a first polymer chain portion in said first layer and a second polymer chain portion in said second layer.

17. The process of claim 15 wherein the first and second layers are co-cured such that the autodeposition coating undergoes a first cross-linking reaction and the second layer of paint is cured and/or undergoes a second cross-linking reaction, wherein the first and second cross-linking reactions are of different types.

18. The process of claim 17 wherein the film forming polymer molecules are an epoxy-acrylic hybrid and the uncured paint layer is a COOH functional polyester paint.

19. The process of claim 18 wherein the COOH functional polyester paint comprises an isocyanurate or a hydroxyl alkyl amide.

20. The process of claim 19 wherein the COOH functional polyester paint comprises a triglycidyl isocyanurate.

21. The

Assignees

• Henkel Ag & Co Kgaa

Inventors

• ABU SHANAB Omar L
• Inch Michael
• Ahmed Bashir M
• Weller Christopher G
• Smith Derek W

Classifications

• C09D5/44

  for electrophoretic applications (processes for coating by electrophoresis C25D13/00) · CPC title

• Y10T428/31678

  Of metal · CPC title

• B05D7/144 Primary

  After-treatment of auto-deposited coatings · CPC title

• Y10T428/31529

  Next to metal · CPC title

• B05D7/542

  the two layers being cured or baked together · CPC title