Weldable compositions comprising a conductive pigment and silicon and methods for using the same

• US 7,147,897 B2
• Filed: 11/06/2002
• Issued: 12/12/2006
• Est. Priority Date: 11/06/2002
• Status: Expired due to Fees

• Current Assignee: PPG Industries Ohio Incorporated (Nouryon BV)
• Original Assignee: PPG Industries Ohio Incorporated (Nouryon BV)
• Inventors: Hopkins, Daniel L., Pawlik, Michael J., Perrine, Steven D., Gray, Ralph C.
• Primary Examiner(s): Feely, Michael J.
• Application Number:
  US10/288,791
• Publication Number:
  US 20040084657A1
• Time in Patent Office: 1,497 Days
• Field of Search: None
• US Class Current: 427/386
• CPC Class Codes: B23K 35/226 Non-corrosive coatings; Primers applied before welding
• CPC Class Codes: C08G 18/587 having phosphorus
• CPC Class Codes: C08G 2150/90 Compositions for anticorrosive coatings
• CPC Class Codes: C08G 59/4071 phosphorus containing compounds
• CPC Class Codes: C08K 3/013 Fillers, pigments or reinforcing additives
• CPC Class Codes: C08K 3/36 Silica
• 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 2666/20 Macromolecular compounds having nitrogen in the main chain according to C08L75/00 - C08L79/00; Derivatives thereof
• CPC Class Codes: C08L 75/04 Polyurethanes
• 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: C09D 5/106 containing Zn
• CPC Class Codes: C09D 5/24 Electrically-conducting paints conductive materials H01B1/00
• CPC Class Codes: Y10T 428/31522 Next to metal

Abstract

A weldable coating composition is disclosed. The composition comprises a binder in which is dispersed a conductive pigment and a source of silicon. Enhanced corrosion protection is offered, without sacrificing weldability of the coating layer. The composition is applied to and cured on a metal substrate.

Claims

1. A weldable composition comprising:

a) a binder comprising the reaction product of one or more epoxy-containing materials and one or more phosphorous-containing materials;

b) a conductive pigment; and

c) a particulate material consisting essentially of elemental silicon.

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

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

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

6. The weldable 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 weldable composition of claim 1, wherein the equivalent ratio of the phosphorus-containing material to epoxy-containing material is from 0.5 to 3.5:

1.

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

9. The weldable composition of claim 8, wherein the curing agent is an aminoplast.

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

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

12. The composition of claim 9, wherein the conductive pigment is iron phosphide.

13. The weldable composition of claim 1, wherein the conductive pigment is selected from the group consisting of zinc, aluminum, graphite, iron phosphide, tungsten, carbon black, and mixtures thereof.

14. The weldable composition of claim 13, wherein the conductive pigment is zinc and/or iron phosphide.

15. The weldable composition of claim 1, wherein the weight percent of (a) is from 20 to 90, based on the total weight of the composition.

16. The weldable composition of claim 1, wherein the weight percent of (b) is from 2 to 30, based on the total weight of the composition.

17. The weldable composition of claim 1, wherein the weight percent of (c) is from 0.5 to 30, based on the total weight of the composition.

18. The weldable composition of claim 1, wherein the weight ratio of (b) to (a) is from 0.2to 10.

19. The weldable composition of claim 1, wherein the weight ratio of (c) to (b) is from 0.02 to 2.0.

20. The weldable composition of claim 1 further comprising one or more corrosion resistant pigments.

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

22. The weldable 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 20°

C. to 150°

C.;

b) curing the coating composition on the metal substrate.

24. The process of claim 23, wherein the metal substrate comprises a ferrous metal, a non-ferrous metal, or a combination thereof.

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