Substrate with a photocatalytic coating

• US 6,465,088 B1
• Filed: 09/05/2000
• Issued: 10/15/2002
• Est. Priority Date: 03/05/1998
• Status: Expired due to Term

• Current Assignee: Saint-Gobain Glass France (Compagnie De Saint-Gobain), Rhodia Chimie (Solvac SA)
• Original Assignee: Saint-Gobain Glass France (Compagnie De Saint-Gobain)
• Inventors: Talpaert, Xavier, Chopin, Thierry, Lehaut, Corinne, Magnin-Feysot, Frédéric, Simonet, Michel
• Primary Examiner(s): Nakarani, D. S.
• Application Number:
  US09/655,146
• Time in Patent Office: 770 Days
• Field of Search: 428/323, 428/639, 428/640, 428/304.4, 428/307.3, 428/312.2, 428/312.8, 428/318.4, 428/318.6, 428/319.1, 428/328
• US Class Current: 428/307.3
• CPC Class Codes: B01J 35/30 characterised by their physical properties
• CPC Class Codes: B01J 35/39 Photocatalytic properties
• 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 2217/212 TiO2
• CPC Class Codes: C03C 2217/45 Inorganic continuous phases
• CPC Class Codes: C03C 2217/475 Inorganic materials
• CPC Class Codes: C03C 2217/477 Titanium oxide
• CPC Class Codes: C03C 2217/71 Photocatalytic coatings
• CPC Class Codes: C03C 2218/113 by sol-gel processes
• CPC Class Codes: C04B 20/008 Micro- or nanosized fillers, e.g. micronised fillers with particle size smaller than that of the hydraulic binder colloidal silica C04B14/062 ; silica fume C04B18/146
• CPC Class Codes: C04B 41/4554 the coating or impregnating material being an organic or organo-metallic precursor of an inorganic material
• CPC Class Codes: C04B 41/4582 Porous coatings, e.g. coating containing porous fillers
• CPC Class Codes: C04B 41/463 Organic solvents
• CPC Class Codes: C04B 41/5041 Titanium oxide or titanates
• CPC Class Codes: C09D 1/00 Coating compositions, e.g. paints, varnishes or lacquers, based on inorganic substances
• CPC Class Codes: C23C 30/00 Coating with metallic material characterised only by the composition of the metallic material, i.e. not characterised by the coating process C23C26/00, C23C28/00 take precedence
• CPC Class Codes: H01J 29/88 provided with coatings on the walls thereof; Selection of materials for the coatings H01J29/868 and H01J29/89 take precedence
• CPC Class Codes: Y10T 428/1266 O, S, or organic compound in metal component
• CPC Class Codes: Y10T 428/12667 Oxide of transition metal or Al
• CPC Class Codes: Y10T 428/249953 : Composite having voids in a component [e.g., porous, cellular, etc.]
• CPC Class Codes: Y10T 428/249956 : Void-containing component is inorganic
• CPC Class Codes: Y10T 428/249967 : Inorganic matrix in void-containing component
• CPC Class Codes: Y10T 428/24997 : Of metal-containing material
• CPC Class Codes: Y10T 428/249987 : With nonvoid component of specified composition
• CPC Class Codes: Y10T 428/249988 : Of about the same composition as, and adjacent to, the void-containing component
• CPC Class Codes: Y10T 428/24999 : Inorganic
• CPC Class Codes: Y10T 428/256 : Heavy metal or aluminum or compound thereof
• CPC Class Codes: Y10T 428/259 : Silicic material

Abstract

The present invention is directed to a process for obtaining a substrate provided with a coating having photocatalytic properties, wherein the coating includes crystallized particles of an oxide of a metal A having photocatalytic properties. The crystallized particles are incorporated into the coating using a mineral binder comprising at least one oxide of a metal B also having photocatalytic properties in the crystallized state. The coating optionally includes at least oxide of a metal M devoid of photocatalytic properties and/or at least one silicon compound of the silicon oxide SiO₂ type. The coating is deposited from liquid-phase dispersions containing the crystallized particles of the oxide of metal A and at least one precursor compound for the oxide of metal B of the binder and optionally a precursor compound for the oxide of metal M and for the Si compound, in a relative proportion A/(B+M+Si) by weight of the metals and Si ranging between 60/40 and 40/60. The present invention is also directed to substrates containing a photocatalytic coating and to liquid-phase dispersions which are used in the preparation of the photocatalytic coatings.

Claims

1. A coated substrate prepared by a process comprising:

(a) preparing a substrate for deposition with a coating, wherein the coating comprises crystallized particles of an oxide of a metal A having photocatalytic properties, a mineral binder comprising at least one oxide of a metal B having photocatalytic properties, optionally at least one oxide of a metal M devoid of photocatalytic properties, and optionally at least one silicon oxide;

(b) depositing the coating onto a surface of the substrate, by depositing the coating from liquid-phase dispersions containing oxides of the metals A and B, optionally the oxide of metal M and optionally the silicon oxide, in a relative proportion by weight of the metals and Si given by A/(B+M+Si), the relative proportion ranging from 60/40 to 40/60; and

(c) allowing the coating to set;

to provide the coated substrate, wherein the coating comprises crystallized particles of the oxide of metal A having photocatalytic properties incorporated into the coating using an at least partially crystallized mineral binder comprising the oxide of metal B also having photocatalytic properties in the crystallized state, optionally at least one oxide of a metal M devoid of photocatalytic properties and optionally a silicon oxide, wherein the coating has a porosity of between 45% and 65%.

2. The coated substrate of claim 1, wherein the crystallized particles have a size of about 5 nm to about 80 nm.

3. The coated substrate of claim 1, wherein the mineral binder is at least partially in the form of grains having a size of between 5 nm to 25 nm.

4. The coated substrate of claim 1, wherein the coating comprises a partially crystallized mineral binder comprising TiO₂ and crystallized TiO₂ particles essentially in anatase form.

5. The coated substrate of claim 1, wherein at least one layer is inserted between the substrate and the coating.

6. The coated substrate of claim 5, wherein the at least one layer functions as a barrier to alkali metals or has an optical, antistatic, or adhesion function.

7. The coated substrate of claim 6, wherein the at least one layer is based on a Si compound or a doped metal oxide.

8. The coated substrate of claim 7, wherein the doped metal oxide is a fluorine-doped tin oxide.

9. The coated substrate of claim 1, wherein the substrate comprises at least one transparent material of glass, plastic, or composite materials.

10. The coated substrate of claim 1, wherein the coating comprises silicon oxide.

11. The coated substrate of claim 1, wherein the at least one oxide of metal B is selected from oxide of Ti, Zn, Sn, and W.

12. A coated substrate prepared by a process comprising:

(a) preparing a substrate for deposition with a coating, wherein the coating comprises crystallized particles of an oxide of a metal A having photocatalytic properties, a mineral binder comprising at least one oxide of a metal B having photocatalytic properties, optionally at least one oxide of a metal M devoid of photocatalytic properties, and optionally at least one silicon oxide;

(b) depositing the coating onto a surface of the substrate, by depositing the coating from liquid-phase dispersions containing oxides of the metals A and B, optionally the oxide of metal M and optionally the silicon oxide, in a relative proportion by weight of the metals and Si given by A/(B+M+Si), the relative proportion ranging from 60/40 to 40/60; and

(c) allowing the coating to set, to provide the coated substrate, wherein the coating comprises crystallized particles of the oxide of metal A having photocatalytic properties incorporated into the coating using an at least partially crystallized mineral binder comprising the oxide of metal B also having photocatalytic properties in the crystallized state, optionally at least one oxide of a metal M devoid of photocatalytic properties and optionally a silicon oxide, wherein the coating has a refractive index of between about 1.5 and 2.

13. The coated substrate of claim 12, wherein the coating comprises silicon oxide.

14. The coated substrate of claim 12, wherein the at least one oxide of metal B is selected from oxide of Ti, Zn, Sn, and W.

15. A coated substrate prepared by a process comprising:

(a) preparing a substrate for deposition with a coating, wherein the coating comprises crystallized particles of an oxide of a metal A having photocatalytic properties, a mineral binder comprising at least one oxide of a metal B having photocatalytic properties, optionally at least one oxide of a metal M devoid of photocatalytic properties, and optionally at least one silicon oxide;

(b) depositing the coating onto a surface of the substrate, by depositing the coating from liquid-phase dispersions containing oxides of the metals A and B, optionally the oxide of metal M and optionally the silicon oxide, in a relative proportion by weight of the metals and Si given by A/(B+M+Si), the relative proportion ranging from 60/40 to 40/60; and

(c) allowing the coating to set, to provide the coated substrate, wherein the coating comprises crystallized particles of the oxide of metal A having photocatalytic properties incorporated into the coating using an at least partially crystallized mineral binder comprising the oxide of metal B also having photocatalytic properties in the crystallized state, optionally at least one oxide of a metal M devoid of photocatalytic properties and optionally a silicon oxide, wherein the coating has a porosity of between 45% and 65% and coherence domains having a size of about 5 nm to about 20 nm.

16. The coated substrate of claim 15, wherein the coating comprises silicon oxide.

17. The coated substrate of claim 15, wherein the at least one oxide of metal B is selected from oxide of Ti, Zn, Sn, and W.

18. A coated substrate prepared by a process comprising:

(a) preparing a substrate for deposition with a coating, wherein the coating comprises crystallized particles of an oxide of a metal A having photocatalytic properties, a mineral binder comprising at least one oxide of a metal B having photocatalytic properties, optionally at least one oxide of a metal M devoid of photocatalytic properties, and optionally at least one silicon oxide;

depositing the coating onto a surface of the substrate, by depositing the coating from liquid-phase dispersions containing oxides of the metals A and B, optionally the oxide of metal M and optionally the silicon oxide, in a relative proportion by weight of the metals and Si given by A/(B+M+Si), the relative proportion ranging from 60/40 to 40/60; and

(c) allowing the coating to set, to provide the coated substrate, wherein the coating comprises crystallized particles of the oxide of metal A having photocatalytic properties incorporated into the coating using an at least partially crystallized mineral binder comprising the oxide of metal B also having photocatalytic properties in the crystallized state, optionally at least one oxide of a metal M devoid of photocatalytic properties, and optionally a silicon oxide, wherein the coating comprises a mineral binder comprising partially crystallized TiO₂ and crystallized TiO₂ particles essentially in anatase form, has a porosity, calculated from the refractive index, of between 45% and 65%, and is present in an amount of between 15 and 45 μ

g/cm².

19. The coated substrate of claim 18, wherein the coating comprises silicon oxide.

20. The coated substrate of claim 18, wherein the at least one oxide of metal B is selected from oxide of Ti, Zn, Sn, and W.