Coating system for cement composite articles
View Patent ↗A coated article which includes a cement fiberboard substrate and a radiation-curable coating system applied to the substrate. The coating system includes an aqueous dispersion of water-dispersible polymer particles, one or more olefinic compounds and water, and may be provided in the form of one or more coating compositions that may be applied in one or more layers, wherein each of the coating compositions is preferably an aqueous composition, or can be mixed with another composition (e.g., on the substrate) to form an aqueous composition.
1. A coated article, comprising:
a cement fiberboard substrate; and
a radiation-curable coating system applied to the substrate;
wherein the coating system comprises:
an aqueous dispersion of water-dispersible polymer particles that are functionalized so that the water-dispersible polymer of such particles can participate in radiation curing; and
about 2 to about 50% by weight, based on the total weight of nonvolatile components in the coating system, of one or more olefinic compounds; and
wherein the coating system includes one or more coating compositions that may be applied in one or more layers.
2. The article of claim 1 , wherein the coating system further comprises a UV photoinitiator system.
3. The article of claim 1 , wherein the water-dispersible polymer comprises a polyurethane.
4. The article of claim 1 , wherein the coating system further comprises a latex polymer.
5. The article of claim 1 , wherein the coating system comprises a first composition that includes one or more olefinic compounds and a second composition that includes a water-dispersible polymer and water and wherein the coating system is cured using radiation.
6. The article of claim 5 , wherein the one or more olefinic compounds comprise a (meth)acrylate, vinyl, vinyl ether, allyl ether, vinyl ester, unsaturated oil, unsaturated fatty acid, or combination thereof.
7. The article of claim 6 , wherein the one or more olefinic compounds comprise isobornyl (meth)acrylate, isodecyl (meth)acrylate, phenoxyethyl (meth)acrylate, trimethylolpropane tri(meth)acrylate, alkoxylated cyclohexane dimethanol di(meth)acrylate, trimethylolpropane ethoxylate tri(meth)acrylate, dipropylene glycol di(meth)acrylate, tripropylene glycol di(meth)acrylate, hexanediol di(meth)acrylate, tetrahydrofurfuryl (meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, ditrimethylolpropane tetra(meth)acrylate, propoxylated glycerol tri(meth)acrylate, beta-carboxyethyl (meth)acrylate, bisphenol A ethoxylate di(meth)acrylate, ethoxylated neopentyl glycol di(meth)acrylate, propoxylated neopentyl glycol di(meth)acrylate, or combination thereof.
8. The article of claim 7 , wherein the one or more olefinic compounds comprise trimethylolpropane tri(meth)acrylate, bisphenol A ethoxylate di(meth)acrylate, propoxylated glycerol tri(meth)acrylate, trimethylolpropane ethoxylate tri(meth)acrylate, ditrimethylolpropane tetra(meth)acrylate or combination thereof.
9. The article of claim 5 , wherein the one or more olefinic compounds comprise a monomer.
10. The article of claim 5 , wherein the one or more olefinic compounds comprise an oligomer.
11. The article of claim 1 , wherein at least one of the coating compositions is UV curable.
12. The article of claim 1 , wherein the water-dispersible polymer is radiation curable.
13. The article of claim 1 , wherein the coating system further comprises a water-soluble silicate salt.
14. The article of claim 13 , wherein the water-soluble silicate salt comprises potassium silicate.
15. The article of claim 1 , wherein a topcoat is applied over the coating system.
16. The article of claim 1 , wherein the cement fiberboard substrate is in the form of a siding product.
17. The article of claim 1 , wherein the coated article when radiation cured can withstand at least 30 freeze-thaw cycles.
18. The article of claim 17 , wherein the coated article can withstand at least 75 freeze-thaw cycles.
19. The article of claim 18 , wherein the coated article can withstand at least 175 freeze-thaw cycles.
20. The article of claim 1 , wherein the coating system has a VOC of less than about 5% based on the total weight of the coating system.
21. The article of claim 1 , wherein the coating system has a VOC of less than about 2% based on the total weight of the coating system.
22. The article of claim 1 , wherein the coating system has a VOC of less than about 0.5% based on the total weight of the coating system.
23. The article of claim 1 , wherein the water-dispersible polymer is functionalized with olefinic groups.
24. The article of claim 1 , wherein the water-dispersible polymer is functionalized with auto-oxidative carbon-carbon double bonds.
25. The article of claim 1 , wherein the coating system contains 10 to 35% by weight olefinic compounds, based on the total weight of nonvolatile components in the coating system.
26. A method for making a coated article, which method comprises:
providing a cement fiberboard substrate;
coating at least a portion of the substrate with a radiation-curable coating system of claim 1 ; and
radiation-curing the coating.
27. A method according to claim 26 comprising coating the substrate with a first coating composition comprising the one or more olefinic compounds followed by a second coating composition comprising the aqueous dispersion of polymer particles.
28. A coated article prepared according to the method of claim 26 .
29. A coated article, comprising:
a cement fiberboard substrate; and
a radiation-curable coating system applied to the substrate;
wherein the coating system comprises a polyurethane dispersion of polymer particles that are functionalized so that the polyurethane can participate in radiation curing and at least 2% by weight, based on the total weight of nonvolatile components in the coating system, of one or more olefinic compounds, the coating system includes one or more coating compositions that may be applied in one or more layers, and at least one of the one or more coating compositions is an aqueous composition.
30. The article of claim 29 , wherein the coating system contains 10 to 35% by weight olefinic compounds, based on the total weight of nonvolatile components in the coating system.