Substrate with a self-cleaning coating

• US 20050221098A1
• Filed: 04/16/2003
• Published: 10/06/2005
• Est. Priority Date: 04/17/2002
• Status: Abandoned Application

• Current Assignee: Saint-Gobain Glass France (Compagnie De Saint-Gobain)
• Original Assignee: Saint-Gobain Glass France (Compagnie De Saint-Gobain)
• Inventors: Brasy, Sebastien, Azzopardi, Marie-Jose
• Application Number:
  US10/511,677
• Publication Number:
  US 20050221098A1
• Time in Patent Office: Days
• US Class Current: 428/446
• CPC Class Codes: B01J 21/063 Titanium; Oxides or hydroxides thereof
• CPC Class Codes: B01J 35/002 Catalysts characterised by their physical properties
• CPC Class Codes: B01J 35/004 Photocatalysts
• CPC Class Codes: B01J 35/023 Catalysts characterised by dimensions, e.g. grain size
• CPC Class Codes: B01J 35/30 characterised by their physical properties
• CPC Class Codes: B01J 35/39 Photocatalytic properties
• CPC Class Codes: B01J 35/40 characterised by dimensions, e.g. grain size in a colloidal state B01J35/23; crystallite size B01J35/77
• CPC Class Codes: B01J 37/0238 via the gaseous phase-sublimation
• CPC Class Codes: B01J 37/347 Ionic or cathodic spraying; Electric discharge
• CPC Class Codes: C03C 17/3417 all coatings being oxide coatings
• CPC Class Codes: C03C 17/3423 at least one of the coatings comprising a suboxide
• CPC Class Codes: C03C 17/3435 comprising a nitride, oxynitride, boronitride or carbonitride
• CPC Class Codes: C03C 17/3441 comprising carbon, a carbide or oxycarbide
• CPC Class Codes: C03C 25/52 Coatings containing inorganic materials only
• CPC Class Codes: C04B 2111/2061 Materials containing photocatalysts, e.g. TiO2, for avoiding staining by air pollutants or the like
• CPC Class Codes: C04B 41/4531 by C.V.D.
• CPC Class Codes: C04B 41/5035 Silica
• CPC Class Codes: C04B 41/5041 Titanium oxide or titanates
• CPC Class Codes: C04B 41/5059 Silicon carbide
• 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: Y10T 428/24926 : including ceramic, glass, porcelain or quartz layer

Abstract

The invention relates to a substrate (1) provided with a first coating (2) comprising at least one hydrophilic layer based on an at least partially oxidized silicon derivative, surmounted by a photocatalytic second coating (3) comprising partially crystallized titanium oxide and having a discontinuous/permeable structure. Application of this substrate to glazing, an architectural material or to mineral wool.

Claims

1. A substrate (1), optionally transparent or optionally essentially transparent, comprising a material selected from glass;

one or more polymers;

a ceramic substrate;

a glass-ceramic substrate;

a substrate made of an architectural material;

a substrate made of an architectural material of the type comprising a wall render, concrete slab or block;

architectural concrete;

roof tile;

material of cementitious composition;

terracotta;

slate;

stone;

metal;

a mineral fibrous substrate;

a fibrous substrate based on glass of the insulation mineral wool type or reinforcement glass yarns;

or combinations thereof; and

comprising on at least part of its surface a first coating (2), comprising a layer, or several stacked layers, based on an at least partly oxidized derivative of silicon, selected from silicon dioxide, substoichiometric silicon oxides and a silicon oxycarbide, oxynitride or oxycarbonitride, and wherein said first coating (2) exhibits hydrophilicity and is surmounted by a second coating (3) having photocatalytic properties, and which comprises at least partly crystallized titanium oxide, said second coating (3) having a discontinuous/permeable structure.

2. The substrate as claimed in claim 1, wherein said substrate is essentially transparent, flat or curved, and optionally of the impressed glazing type.

3. The substrate (1) as claimed in claim 1, wherein the refractive index of the first coating (2) is between 1.45 and 1.80.

4. The substrate (1) as claimed in claim 1, wherein the first coating (2) is deposited by sol-gel or by pyrolysis, or by a vacuum technique of the sputtering type.

5. The substrate (1) as claimed in claim 1, wherein the first coating (2) has a thickness of at least 5 nm.

6. The substrate (1) as claimed in claim 1, wherein the first coating (2) is rough, and has an external surface with nanoscale protuberances and/or indentations.

7. The substrate (1) as claimed in claim 6, wherein the first coating (2) has an external surface exhibiting protuberances, at least some of which are not touching.

8. The substrate (1) as claimed in claim 6, wherein the first coating (2) has, on the external surface, protuberances and/or indentations with a diameter of between 5 and 300 nm.

9. The substrate (1) as claimed in claim 6, wherein the first coating (2) has, on the external surface, protuberances and/or indentations with a height/depth of between 5 and 100 nm.

10. The substrate (1) as claimed in claim 6, wherein the first coating (2) has an external surface comprising between 5 and 300 protuberances per μ

m² of substrate.

11. The substrate (1) as claimed in claim 6, wherein the first coating (2) has an rms roughness of between 4 and 12 nm.

12. The substrate (1) as claimed in claim 1, wherein the second coating (3) has a thickness of at most 10 nm in the regions of overlap with the first coating (2).

13. The substrate (1) as claimed in claim 1, wherein the second coating (3) is essentially based on optionally doped titanium oxide, comprising grains or crystallites with a diameter of between 0.5 and 100 nm.

14. The substrate (1) as claimed in claim 6, wherein the second coating (3) is essentially based on optionally doped titanium oxide, comprising grains or crystallites, and wherein the diameter of the first coating (2) to the diameter of the grains or crystallites of the second coating (3) is at least 2.

15. The substrate (1) as claimed in claim 1, wherein the substrate provided with the first (2) and second (3) coatings has an rms roughness of between 4 and 15.

16. The substrate (1) as claimed in claim 1, wherein the second coating (3) follows the roughness of the first coating (2).

17. The substrate as claimed in claim 7 wherein the grains/crystallites of the second coating (3) lie between the indentations/protuberances of the external surface of the first coating (2), and optionally partially or fully cover said indentations/protuberances.

18. The substrate (1) as claimed in claim 1, wherein the second coating (3) corresponds to an amount of material of at most 10 micrograms per cm² of substrate.

19. The substrate (1) as claimed in claim 1, wherein the second coating (3) is deposited by sol-gel, by pyrolysis, or by a vacuum technique of the sputtering type.

20. The glass substrate (1) as claimed in claim 1, wherein the first and second coatings are deposited by chemical vapor deposition on a ribbon of float glass.

21. The substrate (1) of a glazing type as claimed in claim 1, wherein the substrate is transparent, and has, once provided with the first and second coatings, a light reflection on the coating side R_L of at most 12%, preferably combined with a* and b* values, such that −

2<

a*<

0 and −

5<

b*<

0.

22. The substrate (1) as claimed in claim 1, wherein the combination of the first and second coatings (2, 3) exhibits photocatalytic activity characterized by a rate of palmitic acid degradation of at least 5 nm/h.

23. The substrate (1) as claimed in claim 1, wherein the combination of the first and second coatings (2, 3) exhibits hydrophilicity characterized by a water contact angle of at most 20°

, with or without exposure to radiation in the ultraviolet and/or in the visible.

24. A method of manufacturing a “

self-cleaning,”

antifogging, anticondensation and antisoiling, glazing, comprising forming the substrate of claim 1, and wherein the substrate comprises a material selected from glass, glass-ceramic or combinations thereof.

25. A method of manufacturing partitions, wall claddings, roofing and flooring, for indoors or outdoors, comprising applying to a surface, or inserting into a frame, the substrate of claim 1, and wherein the substrate comprises an architectural material.

26. A method of manufacturing false ceilings or filtration materials, comprising inserting the substrate of claim 1 into a frame, and wherein the substrate comprises an insulation mineral wool.

27. The method of claim 24, wherein the glazing is selected from the group consisting of buildings of the double-glazing type;

vehicle windows of the windshield;

rear window or side windows of automobiles;

rear-view mirrors;

windows for trains, aircraft and ships;

utilitarian glazing, such as aquarium glass, shop window glass or greenhouse glass;

interior furnishings;

urban furniture;

mirrors;

screens for display systems of the computer;

television or telephone type;

electrically controllable glazing, such electrochromic glazing;

liquid-crystal-type glazing;

electroluminescent glazing and photovoltaic glazing.

28. The substrate (1) as claimed in claim 1, wherein the first coating (2) is deposited by chemical vapor deposition (CVD).

29. The substrate (1) as claimed in claim 13, wherein the second coating (3) is essentially based on optionally doped titanium oxide, comprising grains or crystallites, and wherein the diameter of the first coating (2) to the diameter of the grains or crystallites of the second coating (3) is at least 2.

30. The substrate as claimed in claim 13, wherein the grains/crystallites of the second coating (3) lie between the indentations/protuberances of the external surface of the first coating (2), and optionally partially or fully cover said indentations/protuberances.

31. The substrate (1) as claimed in claim 1, wherein the second coating (3) corresponds to an amount of a material of about 0.5 to 3 micrograms per cm².

32. The substrate (1) as claimed in claim 1, wherein the second coating (3) is deposited by chemical vapor deposition.