Method for coating a cement fiberboard article

• US 8,057,864 B2
• Filed: 07/31/2008
• Issued: 11/15/2011
• Est. Priority Date: 01/31/2006
• Status: Active Grant

• Current Assignee: Axalta Coating Systems Ip Co Llc (Axalta Coating Systems Ltd.)
• Original Assignee: Valspar Sourcing, Inc. (Sherwin-Williams Company)
• Inventors: Brandenburger, Larry B., DeChaine, Daniel W., Killilea, T. Howard, Ubel, Andrew
• Primary Examiner(s): Lightfoot; Elena T
• Application Number:
  US12/183,975
• Publication Number:
  US 20100040797A1
• Time in Patent Office: 1,202 Days
• Field of Search: 427/508, 427/517, 427/421.1, 427/496
• US Class Current: 427/496
• CPC Class Codes: B28B 11/04 for coating or applying engobing layersglazing, engobing C04B
• CPC Class Codes: B28B 11/046 by rolling
• CPC Class Codes: C04B 20/0048 Fibrous materials
• CPC Class Codes: C04B 2103/0046 added as monomers or as oligomers
• CPC Class Codes: C04B 2111/29 Frost-thaw resistance
• CPC Class Codes: C04B 28/02 containing hydraulic cements other than calcium sulfates
• CPC Class Codes: C04B 41/0045 Irradiation; Radiation, e.g. with UV or IR C04B41/0036 takes precedence
• CPC Class Codes: C04B 41/009 characterised by the material treated
• CPC Class Codes: C04B 41/4838 Halogenated polymers
• CPC Class Codes: C04B 41/502 Water
• CPC Class Codes: C04B 41/63 Macromolecular compounds

Abstract

The bottom of a cement fiberboard article is coated by conveying the article across a gap between a first conveyor and second conveyer and applying a liquid radiation-curable coating system to at least the bottom surface of the article while the article passes over the gap. The coating system is radiation-cured to at least a reduced tack state before the coated surface contacts the second conveyor.

Claims

1. A method for coating a cement fiberboard article, which method comprises:

(i) providing a conveying system having a first conveyor, a second conveyer and a gap between them;

(ii) conveying a cement fiberboard article across the gap;

(iii) applying a liquid radiation-curable coating system to at least the bottom surface of the article while the article passes over the gap; and

(iv) at least partially curing the coating system to a reduced tack state with radiation before the coated surface contacts the second conveyor.

2. The method of claim 1, wherein the coating system comprises one or more polyvinyl chloride dispersion resins.

3. The method of claim 1, wherein the radiation is visible light, ultra violet light, electron beam, microwave, gamma radiation, infrared radiation or a combination thereof.

4. The method of claim 3, wherein the radiation is ultra violet radiation.

5. The method of claim 3, wherein the radiation is electron beam.

6. The method of claim 1, wherein the cement fiberboard article is a siding product.

7. The method of claim 1, wherein the coating system has a volatile organic content of less than about 5% based on the total weight of the coating system.

8. The method of claim 7, wherein the coating system has a volatile organic content of less than about 0.5% based on the total weight of the coating system.

9. The method of claim 1, wherein the coating system comprises a UV photoinitiator system.

10. The method of claim 1, wherein the coating system comprises one or more olefinic compounds.

11. The method of claim 10, wherein the olefinic compounds comprise one or more monomers.

12. The method of claim 11, wherein the olefinic compounds comprise one or more (meth)acrylate, vinyl, vinyl ether, allyl ether, vinyl ester, unsaturated oil, unsaturated fatty acid or mixture thereof.

13. The method of claim 1, wherein the coating system comprises a polyvinyl chloride dispersion resin.

14. The method of claim 1, further comprising applying a latex polymer topcoat over the coating system.

15. The method of claim 1, wherein the coated article can withstand at least 30 freeze-thaw cycles.

16. The method of claim 15, wherein the coated article can withstand at least 75 freeze-thaw cycles.

17. The method of claim 16, wherein the coated article can withstand at least 175 freeze-thaw cycles.

18. The method of claim 1, wherein the gap is less than 2.5 meters.

19. The method of claim 1, comprising applying the coating system with a roll coater that helps support the article while it passes over the gap.

20. The method of claim 1, further comprising providing supporting rollers within the gap between a radiation curing unit and a downstream further coating applicator, and applying multiple coating system layers with radiation curing between layers.

21. The method of claim 1, comprising applying the coating system by spraying.

22. The method of claim 1, further comprising subjecting the coated article to drying within the gap to remove at least a portion of any carrier which may be present in the coating system.

23. The method of claim 1, comprising at least partially curing the coating system without requiring drying.

24. The method of claim 1, comprising curing the coating system to an essentially fully cured state before the coated surface contacts the second conveyor.

25. The method of claim 1, wherein the coating system contains water.

26. The method of claim 1, wherein the coating system does not contain water.

27. The method of claim 1, wherein the coating system contains solvent.

28. The method of claim 1, comprising applying the coating system at about 75 to 100% solids by weight.

29. The method of claim 1, comprising applying the coating system at about 85 to 100% solids by weight.

30. The method of claim 1, wherein the coating system contains 100% solids.