Anticorrosion coating composition in aqueous dispersion comprising an organic titanate and/or zirconate

• US 9,150,733 B2
• Filed: 11/25/2013
• Issued: 10/06/2015
• Est. Priority Date: 02/11/2004
• Status: Active Grant

• Current Assignee: NOF Metal Coatings Europe (NOF Corporation)
• Original Assignee: NOF Metal Coatings Europe (NOF Corporation)
• Inventors: Iandoli Espinosa, Antonio Francisco
• Primary Examiner(s): MOORE, MARGARET G
• Application Number:
  US14/088,911
• Publication Number:
  US 20140106155A1
• Time in Patent Office: 680 Days
• US Class Current: 1/1
• CPC Class Codes: C08G 77/00 Macromolecular compounds obtained by reactions forming a linkage containing silicon with or without sulfur, nitrogen, oxygen or carbon in the main chain of the macromolecule
• CPC Class Codes: C08G 77/58 Metal-containing linkages C08G77/485 takes precedence
• CPC Class Codes: C08K 5/5419 containing at least one Si—C bond
• CPC Class Codes: C09D 183/14 in which at least two but not all the silicon atoms are connected by linkages other than oxygen atoms C09D183/10 takes precedence
• CPC Class Codes: C09D 4/00 Coating compositions, e.g. paints, varnishes or lacquers, based on organic non-macromolecular compounds having at least one polymerisable carbon-to-carbon unsaturated bond ; Coating compositions, based on monomers of macromolecular compounds of groups C09D183/00 - C09D183/16
• CPC Class Codes: C09D 5/086 Organic or non-macromolecular compounds
• CPC Class Codes: C09D 5/10 containing metal dust
• CPC Class Codes: C09D 5/106 containing Zn
• CPC Class Codes: C09D 7/63 organic
• CPC Class Codes: C23C 22/83 Chemical after-treatment
• CPC Class Codes: C23C 2222/20 Use of solutions containing silanes
• CPC Class Codes: Y10T 428/31663 As siloxane, silicone or silane

Abstract

Anticorrosion coating compositions for metallic parts based on particulate metal in aqueous dispersion are described. The compositions include an organic titanate or zirconate compatible in aqueous phase or in organic phase, an optional silane-based binder, and water. Also described are methods of forming anticorrosion coatings for metallic parts obtained from the noted coating compositions as well as a metallic substrate provided with the anticorrosion coating. The anticorrosion coatings exhibit excellent corrosion resistance upon baking at temperatures greater than 180° C. and up to 350° C.

Claims

1. An anticorrosion coating for metallic substrate, the coating resulting from baking a coating composition at a temperature between greater than 180°

C. and up to 350°

C., the coating composition including from 0.3% to 24% by weight of at least one of an organic titanate and/or an organic zirconate, from 10% to 40% by weight of a particulate metal or a mixture of particulate metals, at least 1% by weight of a silane-based binder, and water, wherein the sum of the organic titanate and/or zirconate and of the silane-based binder is from 5 to 25% by weight, wherein upon baking, the coated metallic substrate exhibits resistance to corrosion from exposure to saline mist for at least 200 hours without formation of red rust and wherein the anticorrosion coating has a thickness of the dry film between 3 μ

m (11 g/m²) and 30 μ

m (110 g/m²).

2. The anticorrosion coating of claim 1 wherein (i) the organic titanate is selected from the group consisting of titanates compatible in organic phase, titanates compatible in aqueous phase, and combinations thereof, and (ii) the organic zirconate is selected from the group consisting of zirconates compatible in organic phase, zirconates compatible in aqueous phase, and combinations thereof.

3. The anticorrosion coating of claim 2 wherein the titanates compatible in organic phase are C₁-C₈ tetraalkyl titanates and the zirconates compatible in organic phase are C₁-C₈ tetraalkyl zirconates.

4. The anticorrosion coating of claim 3 wherein the C₁-C₈ tetraalkyl titanates are selected from the group consisting of tetraethyl titanate, tetra-n-butyl titanate, octylene glycol titanate and combinations thereof, and the C₁-C₈ tetraalkyl zirconates are selected from the group consisting of tetra-n-propyl zirconate, tetra-n-butyl zirconate, and combinations thereof.

5. The anticorrosion coating of claim 2 wherein the titanates compatible in aqueous phase are chelated organic titanates, and the zirconates compatible in aqueous phase are chelated organic zirconates.

6. The anticorrosion coating of claim 5 wherein the chelated organic titanates are triethanolamine titanates or chelate of titanate and lactic acid and the chelated organic zirconates are triethanolamine zirconates or chelate of zirconate and lactic acid.

7. The anticorrosion coating of claim 1 wherein the particulate metal is selected from the group consisting of zinc, aluminium, zinc alloys, aluminium alloys, and combinations thereof.

8. The anticorrosion coating of claim 7 wherein the alloys include metals selected from the group consisting of aluminium, manganese, magnesium, tin, and combinations thereof.

9. The anticorrosion coating of claim 7 wherein the alloys include a eutectic alloy of zinc and aluminium and a trace of rare earth elements.

10. The anticorrosion coating of claim 1 wherein the silane-based binder comprises a silane having at least one hydrolysable hydroxyl function.

11. The anticorrosion coating of claim 10 wherein the hydrolysable hydroxyl function is a C₁-C₈ alkoxy radical.

12. The anticorrosion coating of claim 1 wherein the silane includes an epoxy function.

13. The anticorrosion coating of claim 1 wherein the silane is selected from the group consisting of di- or trimethoxysilane with an epoxy function, di- or triethoxysilane with an epoxy function, and mixtures thereof.

14. The anticorrosion coating of claim 13 wherein the trimethoxysilane is selected from the group consisting of gamma-glycidoxypropyltrimethoxysilane,beta-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, and mixtures thereof.

15. The anticorrosion coating of claim 1 wherein the coating composition further includes an organic solvent or a mixture of organic solvents.

16. The anticorrosion coating of claim 15 wherein the organic solvent is selected from the group consisting of glycolic solvents, acetates, nitroalcane, alcohols, ketones, white spirit, 2,2,4-trimethyl-1,3-pentanediol isobutyrate (texanol), and mixtures thereof.

17. The anticorrosion coating composition of claim 1 wherein the coating composition further includes from 0.1 to 7% by weight of molybdenum oxide, with respect to the total weight of the composition.

18. The anticorrosion coating composition of claim 1 wherein the coating composition further includes from 0.5 to 10% by weight, with respect to the total weight of the composition, of an anticorrosion reinforcing agent selected from the group consisting of yttrium, zirconium, lanthanum, cerium, praseodymium, in the form of oxides or of salts thereof.

19. The anticorrosion coating composition of claim 1 wherein the coating composition further includes from 0.2 to 4% by weight, with respect to the total weight of the composition, of a corrosion inhibitor pigment.

20. The anticorrosion coating composition of claim 19 wherein the corrosion inhibitor pigment is aluminium tripolyphosphate.

21. The anticorrosion coating composition of claim 1 wherein the coating composition further comprises an agent selected from the group consisting of a thickening agent, a wetting agent, and combinations thereof.

22. The anticorrosion coating composition of claim 21 wherein the thickening agent is present in an amount of 0.005 to 7% by weight with respect to the total weight of the coating composition.

23. The anticorrosion coating composition of claim 21 wherein the wetting agent is present in an amount of 0.1 to 4% by weight with respect to the total weight of the coating composition.

24. The anticorrosion coating of claim 1 wherein the coating exhibits exposure to saline mist for at least 250 hours without formation of red rust.

25. The anticorrosion coating composition of claim 1 wherein the baking operation (i) is performed for 10 to 60 minutes by convection or infrared or (ii) is performed for 30 seconds to 5 minutes by induction.

26. The anticorrosion coating composition of claim 1 wherein prior to the baking operation the coated layer is subjected to a drying operation by supplying thermal energy.

27. The anticorrosion coating composition of claim 26 wherein the drying operation by supplying thermal energy includes at least one of convection, infrared, and induction.

28. The anticorrosion coating composition of claim 27 wherein the drying operation is performed at a temperature of between 30 and 250°

C.

29. The anticorrosion coating composition of claim 28 wherein the drying operation (i) is performed by convection or infrared for 10 to 30 minutes on line or (ii) is performed for 30 seconds to 5 minutes by induction.

30. The anticorrosion coating composition of claim 1 wherein the thickness is between 4 μ

m (15 g/m²) and 12 μ

m (45 g/m²).

31. The anticorrosion coating composition of claim 30 wherein the thickness is between 5 μ

m (18 g/m²) and 10 μ

m (40 g/m²).

32. A coated metallic substrate comprising:

a metallic substrate selected from the group consisting of steel, zinc-coated steel, steel covered with a zinc-based coating, cast iron and aluminum;

a coating disposed on the metallic substrate, the coating resulting from baking a coating composition at a temperature between greater than 180°

C. and up to 350°

C., the coating composition including from 0.3% to 24% by weight of at least one of an organic titanate and/or an organic zirconate, from 10% to 40% by weight of a particulate metal or a mixture of particulate metals, at least 1% by weight of a silane-based binder, and water, wherein the sum of the organic titanate and/or zirconate and of the silane-based binder is from 5 to 25% by weight, wherein upon baking, the coated metallic substrate exhibits resistance to corrosion from exposure to saline mist for at least 200 hours without formation of red rust and wherein the anticorrosion coating has a thickness of the dry film between 3 μ

m (11 g/m²) and 30 μ

m (110 g/m²).

33. The coated metallic substrate of claim 32 wherein the metallic substrate is steel covered with a zinc-based coating.