Patent EA-004759-B1 (EA)
Title: Process for the production of photocatalytic coatings on substrates
Inventor: AMMERLAAN JOHANNES ANDREAS MAR
IPC: C03C27/06
Filed: 2000-06-01
Abstract: 1 A process for the production of a photocatalytically active coated substrate which comprises depositing a titanium oxide coating having a thickness of less than 40 nm on the surface of a substrate by contacting the surface of the substrate having a temperature in the range 645 degree C to 720 degree C with a fluid mixture containing a source of titanium. 2. A process as claimed in claim 1 wherein the substrate is at a temperature in the range 670 degree C to 720 degree C. 3. A process as claimed in either of claims 1 or 2 wherein the fluid mixture is a gaseous mixture comprising s titanium tetraalkoxide as the source of titanium. 4. A process as claimed in any of the proceeding claims wherein the fluid mixture is a gaseous mixture comprising titanium tetraethoxide as the source of titanium. 5. A process as claimed in any of the proceeding claims wherein the fluid mixture is a gaseous mixture comprising titanium chloride as the source of titanium and an ester other than a methyl ester. 6. A process for the production of a photocatalytically active coated substrate which comprises depositing a titanium oxide coating having a thickness of less than 40 nm on a substrate by contacting a surface of the substrate with a fluid mixture comprising titanium chloride and an ester other than a methyl ester, when the substrate is at a temperature in the range 600 degree C to 750 degree C. 7. A process as claimed in any of claims 5 to 6 wherein the ester comprises an alkyl ester having an alkyl group with beta-hydrogen. 8 A process as claimed in any of claims 5 to 7 wherein the ester comprises a carboxylate ester. 9 A process as claimed in any of claims 5 to 8 wherein the ester is an alkyl ester having a C2 to C4 alkyl group. 10 A process as claimed in claim 9 wherein the ester comprises an ethyl ester. 11 A process as claimed in claim 10 wherein the ester comprises ethyl acetate. 12 A process as claimed in claimed in any of claims 5 to 11 wherein the ester is the only source of oxygen in the fluid mixture. 13 A process as claimed in any of the preceding claims wherein the fluid mixture is a gaseous mixture. 14 A process as claimed in any of the preceding claims wherein the process is performed on-line during the float glass production process and the substrate is a glass ribbon. 15 A process as claimed in claim 14 wherein the process is performed in the float bath. 16 A process as claimed in any of the preceding claims wherein the process is performed at substantially atmospheric pressure. 17. A process as claimed in claim 1 wherein the coated substrate has an alkali metal ion blocking under layer. 18. A photocatalytically active coated substrate as claimed in claim 6, characterised in that the coated surface of the substrate has a photocatalytic activity of greater than 5 x 10<-3> cm<-1>min<-1> and in that the coated substrate has a visible light reflection measured on the coated side of 35% or lower. 19 A durable photocatalytically active coated glass as claimed in claim 17 comprising a glass substrate having a coating on one surface thereof, said coating comprising an alkali metal ion blocking under layer and an outer photocatalytically active titanium oxide layer, wherein the coated surface of the substrate is durable to abrasion such that the coated surface remains photocatalytically active after it has been subjected to 300 strokes of the European standard abrasion test. 20. A durable photocatalytically active coated glass as claimed in claim 19 wherein the coated glass has a visible light reflection measured on the coated side of 35% or lower, and wherein the photocatalytically active titanium oxide layer has a thickness of 30 nm or lower. 21. A coated glass as claimed in claim 1, characterised in that the coated surface of the glass has a photocatalytic activity of greater than 8 x 10<-2>cm<-1>min<-1> and in that the coated glass has a visible light reflection measured on the coated side of less than 20%.