COATED GLAZING

Abstract

A coated glazing includes a transparent glass substrate and a coating located on the glass substrate. The coating is provided with at least the following layers in sequence starting from the glass substrate: a first layer having a refractive index of more than 1.6, an optional second layer having a refractive index that is less than the refractive index of the first layer, a third layer based on tin dioxide, a fourth layer based on an oxide of silicon, and a fifth layer based on titanium dioxide, wherein the fifth layer is photocatalytic.

Claims

1-22. (canceled)

23. A coated glazing comprising: a transparent glass substrate, and a coating located on the glass substrate, wherein the coating comprises at least the following layers in sequence starting from the glass substrate: a first layer having a refractive index of more than 1.6, an optional second layer having a refractive index that is less than the refractive index of the first layer, a third layer based on tin dioxide, a fourth layer based on an oxide of silicon, and a fifth layer based on titanium dioxide, wherein the fifth layer is photocatalytic.

24. The coated glazing according to claim 23, wherein the coating consists of the first layer, the second layer, the third layer and the fourth layer.

25. The coated glazing according to claim 23, wherein the first layer has a thickness of at least 5 nm, but at most 35 nm.

26. The coated glazing according to claim 23, wherein the second layer has a thickness of at least 15 nm, but at most 50 nm.

27. The coated glazing according to claim 23, wherein the third layer has a thickness of at least 100 nm, but at most 300 nm.

28. The coated glazing according to claim 23, wherein the fourth layer has a thickness of at least 5 nm, but at most 40 nm.

29. The coated glazing according to claim 23, wherein the fifth layer has a thickness of at least 5 nm, but at most 35 nm.

30. The coated glazing according to claim 23, wherein the first layer is based on an oxide of a metal, preferably wherein the first layer is based on tin dioxide, tin oxide, niobium oxide, titanium dioxide or tantalum oxide, most preferably wherein the first layer is based on tin dioxide.

31. The coated glazing according to claim 23, wherein the second layer is based on an oxide of a metalloid, preferably wherein the second layer is based on silicon dioxide or silicon oxynitride, most preferably wherein the second layer is based on silicon dioxide.

32. The coated glazing according to claim 23, wherein the third layer is based on tin dioxide doped with antimony, niobium and/or neodymium, preferably wherein the third layer is based on tin dioxide doped with antimony.

33. The coated glazing according to claim 23, wherein the coated glazing exhibits a maximum visible light transmittance of 70%, preferably a maximum visible light transmittance of 60%, more preferably a maximum visible light transmittance of 55%, most preferably a maximum visible light transmittance of 50%.

34. The coated glazing according to claim 23, wherein the coated glazing exhibits a maximum visible light film side reflectance of 25%, preferably a maximum visible light film side reflectance of 15%, more preferably a maximum visible light film side reflectance of 10%, most preferably a maximum visible light film side reflectance of 9%.

35. The coated glazing according to claim 23, wherein the coated glazing exhibits a maximum visible light glass side reflectance of 15%, preferably a maximum visible light glass side reflectance of 11%, more preferably a maximum visible light glass side reflectance of 8%, most preferably a maximum visible light glass side reflectance of 7%.

36. The coated glazing according to claim 23, wherein the coated glazing exhibits an a* coordinate in reflection on the film side of at least −10, but at most 5, and a b* coordinate in reflection on the film side of at least −20, but preferably at most −5.

37. The coated glazing according to claim 23, wherein the coated glazing exhibits an a* coordinate in transmission of at least −10, but at most 3, and a b* coordinate in transmission of at least −10, but at most 3.

38. The coated glazing according to claim 23, wherein the coating has a specific photocatalytic activity in accordance with ISO/DIS 10678:2010 of greater than 0.4 nmol/cm.sup.2h, preferably greater than 0.5 nmol/cm.sup.2h, more preferably greater than 0.6 nmol/cm.sup.2h, even more preferably greater than 0.7 nmol/cm.sup.2h, most preferably greater than 0.8 nmol/cm.sup.2h

39. The coated glazing according to claim 23, wherein the coating has a photocatalytic activity in accordance with EN 1096-5:2011 represented by a mean global change of haze of up to 3%, preferably up to 2%, more preferably up to 1.5%, most preferably up to 1%.

40. The coated glazing according to claim 23, wherein the transparent glass substrate is a clear transparent glass substrate.

41. The coated glazing according to claim 23, wherein the coated glazing further comprises a second coating located on an opposing major surface of the glass substrate.

42. A coated glazing comprising: a clear transparent glass substrate and a coating located on the glass substrate, wherein the coating comprises at least the following layers in sequence starting from the glass substrate: a first layer having a refractive index of more than 1.6, wherein the first layer is based on tin dioxide, and wherein the first layer has a thickness of at least 5 nm, but at most 35 nm; a second layer having a refractive index that is less than the refractive index of the first layer, wherein the second layer is based on silicon dioxide, and wherein the second layer has a thickness of at least 15 nm, but at most 50 nm; a third layer based on antimony doped tin dioxide, wherein the third layer has a thickness of at least 100 nm, but at most 300 nm; a fourth layer based on silicon dioxide, wherein the fourth layer has a thickness of at least 5 nm, but at most 40 nm; and a fifth layer based on titanium dioxide, wherein the fifth layer is photocatalytic, and wherein the fifth layer has a thickness of at least 5 nm, but at most 35 nm.

Description

[0098] The invention will now be further described by way of the following specific embodiments, which are given by way of illustration and not of limitation, with reference to the accompanying drawing in which:

[0099] FIG. 1 is a schematic view, in cross-section, of a coated glazing in accordance with certain embodiments of the present invention, and

[0100] FIG. 2 is a CIELAB colour chart of a coated glazing in accordance with certain embodiments of the present invention and comparative coated glazings.

[0101] FIG. 1 shows a cross-section of a coated glazing 1 according to certain embodiments of the present invention. Coated glazing 1 comprises a transparent float glass substrate 2 that has been sequentially coated using CVD with a layer based on tin dioxide 3, a layer based on silicon dioxide 4, a layer based on antimony doped tin oxide 5, a layer based on silicon dioxide 6 and a layer based on titanium dioxide 7. The CVD may be carried out in conjunction with the manufacture of the glass substrate in the float glass process.

EXAMPLES

[0102] Examples 1-4 according to the invention and Comparative Example 2 were prepared using atmospheric pressure CVD as part of the float glass process. The transparent glass substrate used for each Example was clear soda-lime-silica glass with a thickness of 4 mm for Examples 1-4. Comparative Example 1 was commercially available Pilkington Activ™ Blue, of 4 mm thickness.

[0103] The coating for each of Examples 1-4 consisted of the following five layers starting from the glass substrate: SnO.sub.2/SiO.sub.2/SnO.sub.2:Sb/SiO.sub.2/TiO.sub.2. The coating for Comparative Example 2 consisted of the following four layers starting from the glass substrate: SnO.sub.2/SiO.sub.2/SnO.sub.2:Sb/TiO.sub.2.

[0104] The SnO.sub.2 layers were deposited over the glass surface using the following components: [0105] N.sub.2 carrier gas, O.sub.2, dimethyltin dichloride, and H.sub.2O.

[0106] The SiO.sub.2 layers were deposited over the glass surface using the following components: [0107] N.sub.2 carrier gas, He carrier gas, O.sub.2, C.sub.2H.sub.4, and SiH.sub.4.

[0108] The SnO.sub.2:Sb layers were deposited over the glass surface using the following components: −N.sub.2 and He carrier gas, O.sub.2, dimethyltin dichloride, 30-50 wt % triphenyl antimony in ethyl acetate, and H.sub.2O.

[0109] The TiO.sub.2 layers were deposited over the glass surface using the following components: [0110] Titanium tetrachloride in ethyl acetate (ratio EtOAc:TiCl.sub.4 1.8-2.2).

[0111] The optical properties of the resultant coated glazing were determined using a HunterLab™ Ultrascan Pro spectrophotometer. The layer thicknesses of the Examples were determined by scanning electron microscopy (SEM) using an FEI Nova NanoSEM™ 450 and EDAX Octane plus EDS detector with TEAM software. The optical properties and layer thicknesses of the Examples and Comparative Examples are shown below in Tables 1 and 2:

TABLE-US-00001 TABLE 1 Optical properties for Examples 1-4 according to the invention and Comparative Examples 1-2 Transmittance Film Side Reflectance Glass Side Reflectance Example % a* b* % a* b* % a* b* Example 1 49.7 −1.5 −4.6 9.0 −4.4 −14.4 7.2 2.6 −10.0 Example 2 49.7 −1.5 −4.8 8.6 −4.5 −14.4 6.8 2.7 −10.9 Example 3 49.9 −1.6 −4.9 8.7 −4.5 −13.4 6.5 1.9 −11.9 Example 4 49.9 −1.6 −4.7 8.9 −4.0 −13.6 6.4 1.6 −12.5 Comparative 58.6 −6.8 −2.5 15.1 −3.1 −13.9 10.9 −1.4 −14.0 Example 1 Comparative 45.0 −1.0 −1.3 17.3 −5.0 −16.6 9.6 2.2 −14.6 Example 2

TABLE-US-00002 TABLE 2 Layer thicknesses for Examples 1-4 according to the invention and Comparative Examples 1-2 Layer Thicknesses (nm) Example SnO.sub.2 SiO.sub.2 SnO.sub.2:Sb SiO.sub.2 TiO.sub.2 Example 1 14.1 28.3 140.4 10.3 13.1 Example 2 13.6 28.3 140.6 14.9 13.9 Example 3 12.2 28.7 140.4 19.4 14.2 Example 4 11.7 29.2 140.6 21.4 14.6 Comparative — 30.0 — — 17.3 Example 1 Comparative 14.6 29.2 139.7 — 23.7 Example 2

[0112] Table 1 shows that the coated glazings according to the present invention afford an aesthetically pleasing level of visible light transmittance (˜50%). Furthermore, surprisingly these coated glazings exhibit extremely low reflectance from both the film side (˜9%) and the glass side (˜6-7%). These reflectance values compare very favourably with the corresponding values for Comparative Examples 1 (film side ˜15%, glass side ˜11%) and 2 (film side ˜17%, glass side ˜9-10%).

[0113] The comparison between the colour properties of Examples 1-4 and those of Comparative Examples 1-2 is depicted in the CIELAB chart of FIG. 2. The coated glazings of Examples 1-4 exhibit an attractive blue colouration (negative b*) in both transmission and reflection. In transmission, the colour of Examples 1-4 is far less green (negative a*) than the colour of Comparative Example 1 and slightly bluer than both Comparative Examples. Generally, a green colouration is undesirable to observers whereas a blue colouration is acceptable or even attractive, especially for applications such as conservatory windows.

[0114] In both film side and glass side reflection the colouration of Examples 1-4 is similar but generally slightly more neutral than the colouration of the Comparative Examples. Since both the film side and glass side reflectance of Examples 1-4 is so low, the colour in reflection is less critical than the colour in transmission.

[0115] Also, the fact that the coatings of Examples 1-4 have been deposited via CVD means that they are more robust than PVD coatings.

[0116] Examples 1-4 and Comparative Examples 1 and 2 were tested for photocatalytic activity according to ISO/DIS 10678:2010 and the results are shown in Table 3 below.

TABLE-US-00003 TABLE 3 Photocatalytic activity according to ISO/DIS 10678: 2010 for Examples 1-4 and Comparative Examples 1 and 2 Specific photocatalytic Example activity (nmol/cm.sup.2h) Example 1 1.36 Example 2 1.34 Example 3 1.22 Example 4 1.84 Comparative 1.43 Example 1 Comparative 0.69 Example 2

[0117] Table 3 shows that the coatings of Examples 1-4 were generally found to exhibit a specific photocatalytic activity comparable to the coating of Comparative Example 1 and far higher than the coating of Comparative Example 2. Additionally, Examples 1-4 were tested according to EN 1096-5: 2011 regarding self-cleaning performances of coated glass surfaces. All four of Examples 1-4 were found to belong to “Class I” (represented by a mean global change of haze of up to 1%) and can be qualified as presenting self-cleaning performances.

[0118] The invention is not restricted to the details of the foregoing embodiments. The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.