WELDABLE COATING COMPOSITIONS, SUBSTRATES AND RELATED METHODS

Abstract

Provided is a coating composition containing (a) a resinous binder composition including an epoxy-functional polymer; and (b) a solid particulate composition dispersed in the resinous binder composition including (i) an electrically conductive material and (ii) a corrosion inhibitive material. The electrically conductive material (i) and the corrosion inhibitive material (ii) are present in a weight ratio of the conductive material (i) to the corrosion inhibitive material (ii) ranging from 1:8 to 12:1. The composition is characterized in that when applied to a conductive substrate to form a coating thereon, the coating is weldable. Coated substrates and related methods are further provided.

Description

Claims

1. A coating composition comprising (a) a resinous binder composition comprising an epoxy-functional polymer; and(b) a solid particulate composition dispersed in the resinous binder composition comprising (i) an electrically conductive material(ii) a corrosion inhibitive material in a weight ratio of the conductive material (i) to the corrosion inhibitive material (ii) ranging from 1:8 to 12:1,

2. The composition of claim 1, wherein the resinous binder (a) further comprises a curing agent which is reactive with the epoxy-functional polymer.

3. The composition of claim 2, wherein the curing agent comprises cyanoguanadine, benzoguanamine, triazine, and/or melamine.

4. The composition of claim 1, wherein the corrosion inhibitive material comprises silicon, zinc phosphate, aluminum phosphate, calcium molybdate, zinc molybdate, barium molybdate, and/or strontium molybdate.

5. The composition of claim 1, wherein the electrically conductive material comprises zinc, aluminum, graphite, silicon, carbon black, molybdenum sulfide, and/or iron phosphide.

6. The composition of claim 1, further comprising a compound selected from an amine, an imine, mixtures thereof and/or co-polymers thereof.

7. The composition of claim 6, wherein the composition comprises an imine selected from an imidazole and/or a reaction product of an imidazole and an epoxy-functional polymer.

8. The composition of claim 6, wherein the compound is present in an amount sufficient to achieve cure of the composition within 5 to 60 seconds at a peak substrate temperature of at least 120° C.

9. The composition of claim 1, further comprising a rubber and/or rubber-like material.

10. The composition of claim 8, wherein the substrate comprises a metallic substrate.

11. The composition of claim 1, wherein the weight ratio of the conductive material (i) to the corrosion inhibitive material (ii) is 8:1.

12. A coated substrate comprising (a) a conductive substrate; and(b) the coating composition of claim 1 applied to the substrate to form a weldable coating layer thereon.

13. The coated substrate of claim 12, wherein the conductive substrate comprises a metallic substrate.

14. The coated substrate of claim 12, further comprising (c) an electrodeposition primer composition applied to the weldable coating layer of (b) to form an electrodeposition primer layer thereon.

15. The coated substrate of claim 14, wherein the electrodeposition primer layer has a film thickness of less than 25 microns.

16. The coated substrate of claim 14, wherein the electrodeposition primer layer has a film thickness of 20 microns or less.

17. The coated substrate of claim 14, further comprising (d) a primer-surfacer coating composition applied to the electrodeposition primer layer to form a primer-surfacer layer thereon.

18. The coated substrate of claim 17, further comprising (e) a top coat composition applied to the primer-surfacer layer to form a top coat layer thereon.

19. The coated substrate of claim 12, wherein a pretreatment composition is applied to the conductive substrate prior to application of the coating composition of claim 1.

20. The coated substrate of claim 19, wherein the pretreatment composition is substantially free of chromium.

21. The coated substrate of claim 12, wherein the coating composition is applied directly to the substrate surface with no intervening pretreatment and/or coating layer therebetween.

22. A method of coating a conductive substrate comprising (a) providing a conductive substrate; and(b) applying the composition of claim 1 to the substrate.