Corrosion and alkali-resistant compositions and methods for using the same

• US 20040086718A1
• Filed: 11/06/2002
• Published: 05/06/2004
• Est. Priority Date: 11/06/2002
• Status: Abandoned Application

• Current Assignee: PPG Industries Ohio Incorporated (Nouryon BV)
• Original Assignee: PPG Industries Ohio Incorporated (Nouryon BV)
• Inventors: Pawlik, Michael J., Jones, Dennis W., Nugent, Richard M. Jr., Deronne, Laurent, Gray, Ralph C., Disert, Yves Le
• Application Number:
  US10/288,774
• Publication Number:
  US 20040086718A1
• Time in Patent Office: Days
• US Class Current: 428/413
• CPC Class Codes: C08G 59/1488 containing phosphorus
• CPC Class Codes: C08G 59/4071 phosphorus containing compounds
• CPC Class Codes: C08L 2666/16 Addition or condensation polymers of aldehydes or ketones according to C08L59/00 - C08L61/00; Derivatives thereof
• CPC Class Codes: C08L 2666/40 Phosphorus-containing compounds
• CPC Class Codes: C09D 163/00 Coating compositions based on epoxy resins; Coating compositions based on derivatives of epoxy resins
• CPC Class Codes: C09D 5/08 Anti-corrosive paints
• CPC Class Codes: Y10T 428/265 1 mil or less
• CPC Class Codes: Y10T 428/31511 Of epoxy ether
• CPC Class Codes: Y10T 428/31515 As intermediate layer
• CPC Class Codes: Y10T 428/31522 Next to metal
• CPC Class Codes: Y10T 428/31529 Next to metal
• CPC Class Codes: Y10T 428/31678 Of metal

Abstract

A corrosion resistant, alkali resistant coating composition is disclosed. The composition comprises a binder comprising a reaction product of an epoxy-containing material and a phosphorus-containing material together with a curing agent. Aminoplasts, especially melamine-based aminoplasts, are particularly suitable curing agents. A source of silicon can optionally be included. The compositions also provide excellent adhesion and can be used with or without a weldable primer. The compositions are applied to and cured on a metal substrate.

Claims

1. A composition substantially free from conductive pigments comprising:

a) the reaction product of one or more epoxy-containing materials and one or more phosphorus-containing materials; and

b) a curing agent.

2. The composition of claim 1, wherein the epoxy-containing material is a polyglycidyl ether of a polyhydric phenol.

3. The composition of claim 2, wherein the polyhydric phenol is Bisphenol A.

4. The composition of claim 1, wherein the number average molecular weight of the epoxy-containing material is 220 to 25,000, as determined by multiplying the epoxy equivalent by the epoxy functionality.

5. The composition of claim 4, wherein the molecular weight of the epoxy-containing material is 220 to 4500.

6. The composition of claim 1, wherein the phosphorus-containing material is selected from the group consisting of phosphoric acid, a phosphonic acid, and phosphorous acid.

7. The composition of claim 1, wherein the equivalent ratio of the phosphorus-containing material to epoxy-containing material is between 0.5 and 3.5:

1.

8. The composition of claim 1, wherein the curing agent is selected from the group consisting of aminoplast resins, polyisocyanates, polyacids, organometallic complexed materials, polyamines, and polyamides.

9. The composition of claim 7, wherein the curing agent is an aminoplast.

10. The composition of claim 9, wherein the aminoplast is a melamine-formaldehyde condensate.

11. The composition of claim 10, wherein the melamine-formaldehyde condensate comprises at least 40 weight percent of imino groups.

12. The composition of claim 1, wherein the number average molecular weight of a) is from 1000 to 5000.

13. The composition of claim 1, wherein the weight percent of (a) is from 50 to 100, based on the total weight of the composition.

14. The composition of claim 1, wherein the weight percent of (b) is from 5 to 25, based on the total weight of the resinous binder.

15. The composition of claim 1, further comprising one or more corrosion resistant pigments.

16. The composition of claim 1, wherein said composition is aqueous-based.

17. The composition of claim 1, wherein said composition is solvent-based.

23. A process for coating a metal substrate comprising:

a) applying the composition of claim 1 to the metal substrate, wherein the composition is at a temperature of 10°

C. to 85°

C.;

b) curing the coating composition on the metal sheet.

24. The process of claim 23, wherein the metal substrate is selected from the group comprising ferrous metals, non-ferrous metals, and combinations thereof.

25. The process of claim 23, wherein the metal substrate is galvanized before application of the composition.

26. A metal substrate coated by the process of claim 23.

27. A coating layer combination comprising an anti-corrosion layer formed from the composition of claim 1, directly adjacent to a weldable coating layer comprising an electroconductive pigment and a binder.

18. A composition comprising:

a) the reaction product of one or more epoxy-containing materials and one or more phosphorus-containing materials;

b) a curing agent; and

c) a source of silicon.

19. The composition of claim 18, wherein the weight percent of (a) is from 50 to 100, based on the total weight of the composition.

20. The composition of claim 18, wherein the weight percent of (b) is from 5 to 25, based on the total weight of the resinous binder.

21. The composition of claim 18, wherein the weight ratio of (c) is from 1.0 to 30, based on the total weight of the composition.

22. The composition of claim 18, wherein the weight ratio of (c) to (b) is from 0.01 to 1.0.

28. A coating layer combination comprising an anti-corrosion layer formed from the composition of claim 18, directly adjacent to a weldable coating layer comprising an electroconductive pigment and a binder.

29. A weldable, corrosion resistant layer deposited on a substrate, wherein the weldable layer is less than or equal to 2.2 microns, is substantially free of conductive pigments, and is comprised of the cured reaction product of:

a) a reaction product of at least one epoxy-functional material and at least one phosphorus-containing material;

b) a curing agent; and

c) silicon.

30. The layer of claim 29, wherein the epoxy-containing material is a polyglycidyl ether of a polyhydric phenol.

31. The composition of claim 30, wherein the polyhydric phenol is Bisphenol A.

32. The composition of claim 29, wherein the number average molecular weight of the epoxy-containing material is 220 to 25,000, as determined by multiplying the epoxy equivalent by the epoxy functionality.

33. The composition of claim 29, wherein the phosphorus-containing material is selected from the group consisting of phosphoric acid, a phosphonic acid, and phosphorous acid.

34. The composition of claim 29, wherein the curing agent is selected from the group consisting of aminoplast resins, polyisocyanates, polyacids, organometallic complexed materials, polyamines, and polyamides.

35. The composition of claim 34, wherein the curing agent is an aminoplast.

36. The composition of claim 35, wherein the aminoplast is a melamine-formaldehyde condensate.

37. The composition of claim 36, wherein the melamine-formaldehyde condensate comprises at least 40 weight percent of imino groups.

38. The composition of claim 29, wherein the number average molecular weight of a) is from 1000 to 5000.

39. A weldable, corrosion resistant layer deposited on a substrate, wherein the weldable layer is of a thickness to provide corrosion resistance without inhibiting welding, is substantially free of conductive pigments, and is comprised of the cured reaction product of:

a) the reaction product of at least one epoxy-functional material and at least one phosphorus-containing material; and

b) a curing agent.

40. The layer of claim 39, wherein said layer is greater than 0.1 micron and less than 1.0 micron.

41. A method for improving the alkaline resistance of a pretreatment layer, comprising adding an aminoplast to the composition from which the layer is deposited.

42. A coating multilayer comprising:

a) a nonchrome alkaline resistant pretreatment layer; and

b) a coating deposited on the nonchrome alkaline resistant pretreatment layer;

wherein <

10 percent of the coating is removed by alkaline cleaning with an alkaline cleaner having a pH of 13 or higher.