Substrate with a photocatalytic coating

• US 20020119307A1
• Filed: 02/22/2002
• Published: 08/29/2002
• Est. Priority Date: 09/15/1995
• Status: Abandoned Application

• Current Assignee: Saint-Gobain Glass France (Compagnie De Saint-Gobain)
• Original Assignee: Saint-Gobain Glass France (Compagnie De Saint-Gobain)
• Inventors: Boire, Philippe, Talpaert, Xavier
• Application Number:
  US10/079,533
• Publication Number:
  US 20020119307A1
• Time in Patent Office: Days
• US Class Current: 428/336
• CPC Class Codes: C03C 17/002 for flat glass, e.g. float glass
• CPC Class Codes: C03C 17/007 containing a dispersed phase, e.g. particles, fibres or flakes, in a continuous phase
• CPC Class Codes: C03C 17/256 Coating containing TiO2
• CPC Class Codes: C03C 17/3417 all coatings being oxide coatings
• CPC Class Codes: C03C 17/3441 comprising carbon, a carbide or oxycarbide
• CPC Class Codes: C03C 2217/211 SnO2
• CPC Class Codes: C03C 2217/212 TiO2
• CPC Class Codes: C03C 2217/213 SiO2
• CPC Class Codes: C03C 2217/214 Al2O3
• CPC Class Codes: C03C 2217/22 ZrO2
• CPC Class Codes: C03C 2217/23 Mixtures
• CPC Class Codes: C03C 2217/24 Doped oxides
• CPC Class Codes: C03C 2217/45 Inorganic continuous phases
• CPC Class Codes: C03C 2217/477 Titanium oxide
• CPC Class Codes: C03C 2217/479 Metals
• CPC Class Codes: C03C 2217/71 Photocatalytic coatings
• CPC Class Codes: C03C 2217/94 Transparent conductive oxide layers [TCO] being part of a multilayer coating
• CPC Class Codes: C03C 2218/113 by sol-gel processes
• CPC Class Codes: C04B 2111/00818 Enzyme carriers
• CPC Class Codes: C04B 2111/80 Optical properties, e.g. transparency or reflexibility
• CPC Class Codes: C04B 35/00 : Shaped ceramic products characterised by their composition porous ceramic products C04B38/00; ceramic articles characterised by particular shape, see the relevant classes, e.g. linings for casting ladles, tundishes, cups or the like B22D41/02; ceramic substrates for microelectronic semi-conductors H01L23/15; Ceramics compositions containing free metal bonded to carbides, diamond, oxides, borides, nitrides, silicides, e.g. cermets, or other metal compounds, e.g. oxynitrides or sulfides other than as macroscopic reinforcing agents C22C; shaping of ceramics B28B; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products chemical preparation of powders of inorganic compounds C01; infiltration of sintered ceramic preforms with molten metal C04B41/51
• CPC Class Codes: C04B 41/0072 : Heat treatment
• CPC Class Codes: C04B 41/009 : characterised by the material treated
• CPC Class Codes: C04B 41/4562 : Photographic methods, e.g. making use of photo-sensitive materials
• CPC Class Codes: C04B 41/5027 : Oxide ceramics in general; Specific oxide ceramics not covered by C04B41/5029 - C04B41/5051
• CPC Class Codes: C04B 41/5041 : Titanium oxide or titanates
• CPC Class Codes: C04B 41/51 : Metallising , e.g. infiltration of sintered ceramic preforms with molten metal covering materials with metals in general C23C; ceramic compositions containing free metal bonded to carbides, diamond, oxides, borides, nitrides, silicides, e.g. cermets, or other metal compounds, e.g. oxynitrides or sulfides, other than as macroscopic reinforcing agents C22C; infiltration of preforms containing free metal, e.g. cermets C22C
• CPC Class Codes: C04B 41/5105 : with a composition mainly composed of one or more of the noble metals or copper
• 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 41/81 : Coating or impregnation
• CPC Class Codes: C04B 41/89 : for obtaining at least two superposed coatings having different compositions
• CPC Class Codes: G02F 1/1333 : Constructional arrangements; Manufacturing methodsG02F1/135, G02F1/136 take precedence
• CPC Class Codes: G02F 1/133502 : Antiglare, refractive index matching layers
• CPC Class Codes: G02F 1/1533 : structural features not otherwise provided for
• CPC Class Codes: G02F 1/157 : Structural association of cells with optical devices, e.g. reflectors or illuminating devices
• CPC Class Codes: Y10T 428/12611 : Oxide-containing component
• CPC Class Codes: Y10T 428/12993 : Surface feature [e.g., rough, mirror]
• CPC Class Codes: Y10T 428/24802 : Discontinuous or differential coating, impregnation or bond [e.g., artwork, printing, retouched photograph, etc.]
• CPC Class Codes: Y10T 428/24975 : No layer or component greater than 5 mils thick
• CPC Class Codes: Y10T 428/25 : Web or sheet containing structurally defined element or component and including a second component containing structurally defined particles
• CPC Class Codes: Y10T 428/252 : Glass or ceramic [i.e., fired or glazed clay, cement, etc.] [porcelain, quartz, etc.]
• CPC Class Codes: Y10T 428/256 : Heavy metal or aluminum or compound thereof
• CPC Class Codes: Y10T 428/265 : 1 mil or less
• CPC Class Codes: Y10T 428/31841 : Next to cellulosic
• CPC Class Codes: Y10T 428/31938 : Polymer of monoethylenically unsaturated hydrocarbon

Abstract

The subject of the invention is a glass-, ceramic- or vitroceramic-based substrate (1) provided on at least part of at least one of its faces with a coating (3) with a photocatalytic property containing at least partially crystalline titanium oxide.

It also relates to the applications of such a substrate and to its method of preparation.

Claims

1. Glass-, ceramic- or vitroceramic-based substrate (1), provided on at least part off at least one of its faces with a coating (3) with a photocatalytic property with a thickness between 5 and 50 nanometers and containing at least partially crystalline titanium oxide obtained by a pyrolysis technics from at least one precursor, notably an organo-metallic or a metallic halide component.

2. Substrate (1) according to claim 1, characterized in that the crystalline titanium oxide is in the anatase form, in the rutile form or in the form of a mixture of anatase and rutile.

3. Substrate (1) according to claim 1 or claim 2, characterized in that the titaniuim oxide is cyrstalline with a degree of crystallization of at least 25&

, in particular of between 30 and 80%.

4. Substrate (1) according to one of the preceding claims, characterized in that the crystalline titanium oxide is in the form of crystallites with an average size of between 0.5 and 60 nm, preferably 1 to 50 nm, in particular 10 to 40 nm.

5. Substrate (1) according to one of the preceding claims, characterized in that the coating (3) also contains an inorganic material, in particular in the form of an amorphous or partially crystalline oxide or mixture of oxides of the silicon oxide, titanium oxide, tin oxide, zirconium oxide or aluminium oxide type.

6. Substrate (1) according to one of the preceding claims, characterized in that the coating comprises additives capable of accentuating the photocatalytic phenomenon due to the titanium oxide, in particular increasing the absorption band of the coating and/or by increasing the number of charge carriers by doping the crystal lattice of the oxide or by surface doping the coating and/or by increasing the yield and kinetics of the photocatalytic reactions by covering at least part of the coating with a catalyst.

7. Substrate (1) according to claim 6, characterized in that the crystal lattice of the titanium oxide is doped, in particular by at least one of the metal elements from the group comprising niobium, tantalum, iron, bismuth, cobalt, nickel, copper, ruthenium, cerium and molybdenum.

8. Substrate (1) according to claim 6, characterized in that the titanium oxide or the coating (3) in its entirety is coated with a catalyst, in particular in the form of a thin layer of noble metal of the platinum, rhodium, silver or palladium type.

9. Substrate (1) according to claim 6, characterized in that the coating incorporates metal elements, in particular in the form of particles, targeted at increasing its absorption band, elements chosen from tin, cadmium, tungsten, cerium or zirconium.

10. Substrate (1) according to claim 6, characterized in that the surface doping of the titanium oxide or of the coating which contains it is carried out by covering at least part of the said coating with a layer of metal oxide or salts, the metal flung chosen from iron, copper, ruthenium, cerium, molybdenum, bismuth or vanadium.

11. Substrate (1) according to one of the preceding claims, characterized in that the surface of the coating (3) is hydrophilic, with in particular a contact angle with water of less than 5°

after exposure to light radiation, and/or oleophilic.

12. Substrate (1) according to one of the preceding claims, characterized in that the RMS roughness of the coating (3) is between 2 and 20 nm, in particular between 5 and 20 nm.

13. Substrate (1) according to one of the preceding claims, characterized in that at least one thin layer (2) with an anti-static, thermal or optical function or forming a carrier to the migration of the alkali metals originating from the substrate (1) is arranged under the coating (3) with a photocatalytic property.

14. Substrate (1) according to claim 14, characterized in that the thin layer (2) with an anti-static, optionally with controlled polarization, and/or thermal and/or optical function is based on conductive material of the metal type or of the doped metal oxide type, such as ITO, SnO₂:

F, ZnO;

In, ZnO;

F, ZnO;

Al, ZnO;

Sn or metal oxide which is stoichiometrically deficient in oxygen, such as SnO<sub>2−

n</sub> or ZnO<sub>2−

n</sub> with x<

2.

15. Substrate (1) according to claim 13, characterized in that the thin layer (2) with an optical function is based on an oxide or on a mixture of oxides with a refractive index intermediate between that of the coating and that of the substrate, chosen in particular from the following oxides:

Al₂O₃, SnO₂, In₃O₃, silicon oxycarbide or silicon oxynitride.

16. Substrate (1) according to claim 13, characterized in that the thin layer (2) with a barrier function with respect to alkali metals is based on silicon oxide, nitride, oxynitride or oxycarbide, on Al₂O₃:

F or on aluminium nitride.

17. Substrate (1) according to claim 13, characterized in that the coating (3) constitutes the final layer of a stack of anti-glare layers.

18. Monolithic, multiple unit of the double glazing type or laminated “

dirt-repellent and/or anti-condensation”

glazing incorporating the substrate (1) according to one of the preceding claims.

19. Application of the substrate (1) according to one of claims 1 to 17 in the manufacture of anti-condensation and/or dirt-repellent “

self-cleaning”

glazing, where the dirty marks are of organic and/or inorganic type, in particular glazing for buildings of the double glazing type, windows for vehicles of the automobile windscreen, rear window or side window type, trains or planes or utilitarian glazing such as aquarium glass or glass for shop windows, for greenhouses, for interior furniture or for street furniture, or mirrors, television screens, or glazing with electrically controlled variable absorption.

20. Process for obtaining the substrate (1) according to one of claims 1 to 17, characterized in that the coating (3) with a photocatalytic property is deposited by liquid phase pyrolysis, in particular from a solution comprising at least one organometallic titanium precursor of the titanium chelate and/or titanium alcoholate type.

21. Process for obtaining the substrate (1) according to one of claims 1 to 17, characterized in that the coating (3) with a photocatalytic property is deposited by a sol-gel technique, with a method of deposition of the dipping or dip coating, cell coating, spray coating or laminar coating type, from a solution comprising at least one organometallic titanium precursor of the titanium alcoholate type.

22. Process for obtaining the substrate (1) according to one of claims 1 to 17, characterized in that the coating (3) with a photocatalytic property is deposited by vapour phase pyrolysis, CVD, from at least one titanium precursor of the halide or organometallic type.

23. Process according to one of claims 20 to 22, characterized in that the coating (3) with a photocatalytic property is deposited in at least two successive stages.

24. Process according to one of claims 20 to 23, characterized in that the coating (3) with a photocatalytic property is subjected, after deposition, to at least one heat treatment of the annealing type.