Single pack low temperature bake coating composition

1. A coating composition comprising a mixture of:

a) chlorinated polyolefin-modified acrylic latex emulsion,

b) polyurethane dispersion

c) non-gelling self-crosslinking acrylic emulsion, and

d) glycol-based solvent,

wherein the composition contains sufficient non-gelling self-crosslinking acrylic emulsion and glycol-based solvent so that a 0.1 mm wet thickness layer of the composition will form a tack-free film when heated at 65° C. for fifteen minutes, and the glycol-based solvent is selected so that the coating composition is shelf stable.

2. A coating composition according to claim 1 wherein the self-crosslinking acrylic emulsion comprises a crosslinker capable of converting a 0.1 mm wet thickness film of the acrylic emulsion and crosslinker to a tack-free state when heated at 65° C. for fifteen minutes.

3. A coating composition according to claim 2 wherein the crosslinker comprises diacetone acrylamide.

4. A coating composition according to claim 2 wherein the crosslinker comprises a carbodiimide or an aziridine.

5. A coating composition according to claim 1 wherein the glycol solvent is hydrophilic.

6. A coating composition according to claim 1 wherein the glycol solvent comprises ethylene glycol, ethylene glycol methyl ether, ethylene glycol ethyl ether, ethylene glycol monobutyl ether, ethylene glycol-2-ethylhexyl ether, propylene glycol, propylene glycol methyl ether, propylene glycol ethyl ether, propylene glycol monobutyl ether, propylene glycol-2-ethylhexyl ether, diethylene glycol, diethylene glycol methyl ether, diethylene glycol ethyl ether, diethylene glycol monobutyl ether, diethylene glycol-2-ethylhexyl ether, dipropylene glycol, dipropylene glycol methyl ether, dipropylene glycol ethyl ether, dipropylene glycol monobutyl ether, dipropylene glycol-2-ethylhexyl ether, or mixture thereof.

7. A coating composition according to claim 1 wherein the glycol solvent comprises a mixture of dipropylene glycol monomethyl ether and ethylene glycol monobutyl ether.

8. A coating composition according to claim 1 further comprising a low viscosity reactive epoxide diluent and polymerization catalyst.

9. A coating composition according to claim 1 which does not contain N-methyl pyrrolidone.

10. A coating composition according to claim 1 containing sufficient water so that about 20 to about 80 wt. % solids are present when the composition is applied to a substrate.

11. A coating composition according to claim 1 containing sufficient water so that about 35 to about 55 wt. % solids are present when the composition is applied to a substrate.

12. A coating composition according to claim 1 containing about 15 to about 85 wt. % chlorinated polyolefin-modified acrylic latex emulsion, about 5 to about 50 wt. % polyurethane dispersion, about 10 to about 80 wt. % self-crosslinkable acrylic emulsion and about 25 to about 80 wt. % glycol solvent, based on total solids.

13. A coating composition according to claim 1 containing about 25 to about 50 wt. % chlorinated polyolefin-modified acrylic latex emulsion, about 10 to about 20 wt. % polyurethane dispersion, about 30 to about 65 wt. % self-crosslinkable acrylic emulsion and about 30 to about 65 wt. % glycol solvent, based on total solids.

14. A coating composition according to claim 1 having at least three months shelf stability when stored in single pack form at room temperature.

15. A coated article comprising a substrate having thereon a hardened continuous coating obtained from a shelf stable mixture of chlorinated polyolefin-modified acrylic latex emulsion, polyurethane dispersion, non-gelling self-crosslinking acrylic emulsion, and glycol-based solvent.

16. A coated article according to claim 15 comprising a plastic substrate.

17. A coated article according to claim 15 wherein the substrate comprises polyvinyl chloride.

18. A coated article according to claim 15 wherein the substrate comprises polystyrene, thermoplastic polyolefin, acrylonitrile-butadiene-styrene, polycarbonate, nylon or polyester.

19. A coated article according to claim 15 comprising a wood substrate.

20. A coated article according to claim 19 wherein the wood has been treated with a wax-containing preservative.

21. A method for coating a plastic or wooden substrate, which method comprises:

a) applying to the substrate a layer of a shelf stable coating composition comprising a mixture of chlorinated polyolefin-modified acrylic latex emulsion, polyurethane dispersion, non-gelling self-crosslinking acrylic emulsion, and glycol-based solvent, and

b) drying the composition to form a hardened continuous film.

22. A method according to claim 21 wherein the substrate comprises plastic and the composition is dried at a temperature no greater than about 65° C.

23. A method according to claim 21 wherein the substrate comprises wood treated with a wax-containing preservative.

24. A method according to claim 21 wherein the self-crosslinking acrylic emulsion comprises a crosslinker capable of converting a 0.1 mm wet thickness film of the acrylic emulsion and crosslinker to a tack-free state when heated at 65° C. for fifteen minutes.

25. A method according to claim 24 wherein the crosslinker comprises diacetone acrylamide.

26. A method according to claim 21 wherein the composition has at least three months shelf stability when stored in single pack form at room temperature.

27. A method according to claim 21 comprising drying the composition at about 50° to about 65° C. in less than 15 minutes.

28. A method according to claim 21 wherein the hardened film has a dry film thickness of about 13 to about 130 μm.