PHOTOCATALYTIC COATINGS HAVING IMPROVED LOW-MAINTENANCE PROPERTIES

• US 20070264494A1
• Filed: 04/11/2007
• Published: 11/15/2007
• Est. Priority Date: 04/11/2006
• Status: Active Grant

• Current Assignee: Cardinal CG Company (Cardinal Glass Industries Incorporated)
• Original Assignee: Cardinal CG Company (Cardinal Glass Industries Incorporated)
• Inventors: Burrows, Keith, Myli, Kari, Krisko, Annette
• Granted Patent: US 7,862,910 B2
• Time in Patent Office: Days
• US Class Current: 428/336
• CPC Class Codes: B01J 23/30 Tungsten
• CPC Class Codes: B01J 35/004 Photocatalysts
• CPC Class Codes: B01J 35/39 Photocatalytic properties
• CPC Class Codes: B01J 37/0244 Coatings comprising several layers
• CPC Class Codes: C03C 17/3417 all coatings being oxide coatings
• CPC Class Codes: C03C 17/3435 comprising a nitride, oxynitride, boronitride or carbonitride
• CPC Class Codes: C03C 2217/71 Photocatalytic coatings
• CPC Class Codes: C23C 14/08 Oxides C23C14/10 takes precedence
• CPC Class Codes: C23C 14/083 of refractory metals or yttrium
• CPC Class Codes: Y10T 428/265 1 mil or less

Abstract

The invention provides a substrate bearing a photocatalytic coating. In some embodiments, the coating includes a photocatalytic film comprising titania deposited over a layer comprising tungsten oxide, aluminum oxide, niobium oxide or zirconium oxide. Additionally or alternatively, the photocatalytic film can include both titania and a material selected from the group consisting of nitrogen, tantalum, copper and silica. The invention also provides methods of depositing such coatings.

Claims

1. A transparent substrate on which there is provided a photocatalytic coating, the coating including a photocatalytic film deposited directly over an underlying film comprising a material selected from the group consisting of tungsten oxide and niobium oxide.

2. The substrate of claim 1 wherein the photocatalytic film comprises both titania and a material selected from the group consisting of nitrogen, copper, tantalum, silica, palladium, tin, tungsten, niobium, and molybdenum.

3. The substrate of claim 2 wherein the material selected from the group consisting of nitrogen, copper, tantalum, silica, palladium, tin, tungsten, niobium, and molybdenum is a dopant.

4. The substrate of claim 3 wherein the photocatalytic film comprises both titania and tungsten dopant.

5. The substrate of claim 1 wherein the underlying film has a thickness of less than about 250 angstroms.

6. The substrate of claim 1 wherein the underlying film has a thickness of less than about 75 angstroms.

7. The substrate of claim 1 further comprising a base film deposited beneath the underlying film, wherein the base film comprises silica and/or titania.

8. A transparent substrate on which there is provided a photocatalytic coating, the coating including a photocatalytic film comprising titania positioned directly over a film comprising tungsten oxide.

9. The substrate of claim 8 wherein the film comprising tungsten oxide consists essentially of tungsten oxide.

10. The substrate of claim 8 wherein the film comprising tungsten oxide is a mixed film comprising silica, silicon, titania, titanium and/or substoichiometric titanium oxide.

11. The substrate of claim 8 wherein the film comprising tungsten oxide has a thickness of between about 15 angstroms and about 150 angstroms.

12. The substrate of claim 8 wherein the film comprising tungsten oxide is positioned directly over a film comprising silica and/or titania.

13. The substrate of claim 12 wherein the film comprising silica and/or titania has a thickness of less than about 300 angstroms.

14. The substrate of claim 13 wherein the film comprising silica and/or titania has a thickness of less than 100 angstroms.

15. The substrate of claim 8 wherein the photocatalytic film comprises both titania and a material selected from the group consisting of nitrogen, copper, tantalum, silica, palladium, tin, tungsten, niobium, and molybdenum.

16. The substrate of claim 15 wherein the material selected from the group consisting of nitrogen, copper, tantalum, silica, palladium, tin, tungsten, niobium, and molybdenum is a dopant.

17. The substrate of claim 8 wherein the photocatalytic film comprises both titanium and nitrogen.

18. A transparent substrate on which there is provided a photocatalytic coating, the coating comprising, from the substrate outwardly, a base film deposited over the substrate and having a thickness of less than about 300 angstroms, a film comprising tungsten oxide deposited over the base film and having a thickness of less than about 100 angstroms, and a photocatalytic film comprising titania deposited directly over the film comprising tungsten oxide.

19. The substrate of claim 18 wherein the film comprising tungsten oxide has a thickness of less than about 75 angstroms.

20. A method of depositing a photocatalytic coating, the method comprising depositing a film comprising tungsten oxide over a major surface of a glass sheet, and depositing a photocatalytic film comprising titania directly over the film comprising tungsten oxide.

21. The method of claim 20 wherein the film comprising tungsten oxide is deposited at a thickness of between about 15 angstroms and about 150 angstroms.

22. The method of claim 20 wherein the film comprising tungsten oxide is deposited by providing a sputtering target having a sputterable material that comprises tungsten, the sputterable material being selected from the group consisting essentially of pure tungsten, a tungsten oxide, and a tungsten alloy.

23. The method of claim 20 wherein the film comprising tungsten oxide is a mixed film comprising silica, the mixed film being deposited by co-sputtering a target comprising tungsten and a target comprising silicon.

24. The method of claim 20 wherein the photocatalytic film comprises nitrogen, the photocatalytic film being deposited by sputtering a target comprising titanium in an atmosphere comprising nitrogen.

25. A transparent substrate on which there is provided a photocatalytic coating, the coating including a photocatalytic film deposited over an underlying film comprising a material selected from the group consisting of tungsten oxide, niobium oxide, aluminum oxide and zirconium oxide, wherein a film comprising zirconium oxide or niobium oxide is deposited over or under the underlying film, the film comprising zirconium oxide or niobium oxide being a different material than the underlying film.

26. The substrate of claim 25 wherein the underlying film has a thickness of less than about 250 angstroms.

27. The substrate of claim 25 wherein the underlying film has a thickness of less than about 75 angstroms.

28. The substrate of claim 25 wherein the film comprising zirconia or niobium oxide has a thickness of between about 10 angstroms and about 20 angstroms.

29. The substrate of claim 25 wherein the film comprising zirconium oxide or niobium oxide is deposited over the underlying film.

30. The substrate of claim 25 wherein the film comprising zirconium oxide or niobium oxide is deposited under the underlying film.

31. The substrate of claim 25 wherein the film comprising zirconium oxide or niobium oxide is deposited under the underlying film, and wherein a second film comprising zirconium oxide or niobium oxide is deposited over the underlying film.

32. The substrate of claim 25 further comprising a base film deposited beneath the underlying film, wherein the base film comprises silica and/or titania.