CRUSH RESISTANT LATEX TOPCOAT COMPOSITION FOR FIBER CEMENT SUBSTRATES

• US 20070110981A1
• Filed: 11/15/2006
• Published: 05/17/2007
• Est. Priority Date: 11/15/2005
• Status: Active Grant

• Current Assignee: Axalta Coating Systems Ip Co Llc (Axalta Coating Systems Ltd.)
• Original Assignee: Valspar Sourcing, Inc. (Sherwin-Williams Company)
• Inventors: Cavallin, Carl, Killilea, T., Mittelsteadt, William, Carter, Shane, Vetter, Glen
• Granted Patent: US 8,202,578 B2
• Time in Patent Office: Days
• US Class Current: 428/294.700
• CPC Class Codes: C04B 20/0048 Fibrous materials
• CPC Class Codes: C04B 28/02 containing hydraulic cements other than calcium sulfates
• CPC Class Codes: C04B 41/00 After-treatment of mortars, concrete, artificial stone or ceramics; Treatment of natural stone conditioning of the materials prior to shaping C04B40/00; applying liquids or other fluent materials to surfaces, in general B05; grinding or polishing B24; apparatus or processes for treating or working shaped articles of clay or other ceramic compositions, slag or mixtures containing cementitious material B28B11/00; working stone or stone-like materials B28D; glazes, other than cold glazes, C03C8/00; etching, surface-brightening or pickling compositions C09K13/00
• CPC Class Codes: C04B 41/009 characterised by the material treated
• CPC Class Codes: C04B 41/483 Polyacrylates
• CPC Class Codes: C04B 41/52 Multiple coating or impregnating multiple coating or impregnating with the same composition or with compositions only differing in the concentration of the constituents, is classified as single coating or impregnation
• CPC Class Codes: C04B 41/63 Macromolecular compounds
• CPC Class Codes: C04B 41/70 for obtaining at least two superposed coatings having different compositions
• CPC Class Codes: C09D 133/12 Homopolymers or copolymers of methyl methacrylate
• CPC Class Codes: C09D 5/02 Emulsion paints including aerosols
• CPC Class Codes: E04C 2/06 reinforced
• CPC Class Codes: E04D 1/22 of specified materials not covered by any one of groups E04D1/14 - E04D1/205, or of combinations of materials, where at least one is not covered by any one of groups E04D1/14 - E04D1/205
• CPC Class Codes: E04F 13/147 with an outer layer imitating natural stone, brick work or the like
• CPC Class Codes: Y10T 428/249932 Fiber embedded in a layer derived from a water-settable material [e.g., cement, gypsum, etc.]
• CPC Class Codes: Y10T 428/269 including synthetic resin or polymer layer or component
• CPC Class Codes: Y10T 428/31667 Next to addition polymer from unsaturated monomers, or aldehyde or ketone condensation product
• CPC Class Codes: Y10T 428/31855 Of addition polymer from unsaturated monomers

Abstract

A coated fiber cement article in the form of an unattached fiber cement board substrate having a first major surface at least a portion of which is covered with a crush resistant final topcoat composition comprising a multistage latex polymer, and a method for making a crush resistant coated fiber cement article by coating a fiber cement board substrate with such a composition and stacking the coated boards.

Claims

1. A coated fiber cement article comprising an unattached fiber cement board substrate having a first major surface at least a portion of which is covered with a crush resistant final topcoat composition comprising a multistage latex polymer.

2. The article of claim 1, wherein the multistage latex polymer has a gradient Tg.

3. The article of claim 1, wherein the multistage latex polymer comprises at least one soft stage having a Tg less than about 40°

C. and at least one hard stage having a Tg greater than about 40°

C.

4. The article of claim 3, wherein the multistage latex polymer comprises at least one soft stage having a Tg between about −

65 and about 40°

C. and at least one hard stage having a Tg between about 40 and about 230°

C.

5. The article of claim 3, wherein the multistage latex polymer comprises at least one soft stage having a Tg between about −

15 and about 15°

C. and at least one hard stage having a Tg between about 60 and about 105°

C.

6. The article of claim 3, wherein the multistage latex polymer comprises about 50 to about 90 wt. % soft stage polymer morphology based on total polymer weight and about 10 to about 50 wt. % hard stage polymer morphology based on the total multistage latex polymer weight.

7. The article of claim 3, wherein the multistage latex polymer comprises about 60 to about 80 wt. % soft stage polymer morphology based on total polymer weight and about 20 to about 40 wt. % hard stage polymer morphology based on the total multistage latex polymer weight.

8. The article of claim 1, wherein the topcoat composition comprises at least about 10 wt. % multistage latex polymer based on the total composition solids.

9. The article of claim 1, wherein the topcoat composition comprises at least about 25 wt. % multistage latex polymer based on the total composition solids.

10. The article of claim 1, wherein the multistage latex polymer is functionalized.

11. The article of claim 1, wherein the multistage latex polymer comprises acetoacetyl functionality.

12. The article of claim 11, wherein the multistage latex polymer comprises about 0.5 to about 5 wt. % acetoacetyl functionality, based on the total multistage latex polymer weight.

13. The article of claim 1, wherein less than about 20 wt. % styrene is present in or was used to form the multistage latex polymer based upon the total weight of ethylenically unsaturated monomers used to form such polymer.

14. The article of claim 1, wherein less than about 5 wt. % styrene is present in or was used to form the multistage latex polymer based upon the total weight of ethylenically unsaturated monomers used to form such polymer.

15. The article of claim 1, wherein the topcoat composition includes less than 10 wt. % volatile organic compounds.

16. The article of claim 1, wherein the topcoat composition includes less than 7 wt. % volatile organic compounds.

17. The article of claim 1, wherein the topcoat composition includes less than 4 wt. % volatile organic compounds.

18. The article of claim 1, wherein the topcoat composition further comprises at least about 1 wt. % low VOC coalescent.

19. The article of claim 1, wherein the topcoat composition has a pigment volume concentration less than 45%.

20. The article of claim 1, wherein the topcoat composition has a minimum film forming temperature less than about 20°

C.

21. The article of claim 1, wherein the topcoat when dried or otherwise hardened has a total thickness between about 20 and about 200 micrometers.

22. The article of claim 1, wherein the topcoat when dried or otherwise hardened has a Crush Resistance value of at least 3 when two face-to-face coated embossed fiber cement board substrates are subjected to a pressure of about 8 kg/cm².

23. The article of claim 1, wherein the topcoat when dried or otherwise hardened has a Crush Resistance value of at least 3 when two face-to-face coated embossed fiber cement board substrates are subjected to a pressure of about 10 kg/cm².

24. A method of making a crush resistant coated fiber cement article, which method comprises:

providing an unattached fiber cement board substrate having a first major surface;

providing a topcoat coating composition comprising a multistage latex polymer;

applying the topcoat coating composition to at least a portion of the first major surface;

drying or otherwise hardening the coating composition to form a crush resistant final topcoat; and

stacking two or more of the thus-coated boards on a pallet or other horizontal supporting surface.

25. A method according to claim 24 further comprising applying a sealer or primer composition to the first major surface before applying the topcoat coating composition.

26. A method according to claim 24 further comprising placing a pair of the coated boards in face-to-face relationship with a protective liner between the coated surfaces.

27. A method according to claim 26 comprising stacking a plurality of such pairs on a pallet.

28. A method according to claim 27 comprising stacking a plurality of such pallets atop one another.

29. A method according to claim 24 wherein the final topcoat has a Crush Resistance value of at least 3 when two face-to-face coated embossed fiber cement board substrates are subjected to a pressure of about 8 kg/cm².

30. A method according to claim 24 wherein the final topcoat has a Crush Resistance value of at least 3 when two face-to-face coated embossed fiber cement board substrates are subjected to a pressure of about 10 kg/cm².