COATED GLAZING

Abstract

A coated glazing comprising at least the following layers in sequence: a transparent glass substrate, a layer based on an oxide of a metal and/or a layer based on an oxide of a metalloid, and a further layer, wherein either said layer based on an oxide of a metal or said layer based on an oxide of a metalloid is adjacent said transparent glass substrate, wherein said layer that is adjacent said transparent glass substrate comprises a surface that, prior to a coating of said surface, has an arithmetical mean height of the surface value, Sa, of at least 4.0 nm when tested in accordance with ISO 25178-2:2012, and wherein the coated glazing exhibits an average haze value of at least 0.47% when tested in accordance with ASTM D1003-13.

Claims

1.-17. (canceled)

18. A coated glazing comprising at least the following layers in sequence: a transparent glass substrate, a layer based on an oxide of a metal and/or a layer based on an oxide of a metalloid, and a further layer, wherein either said layer based on an oxide of a metal or said layer based on an oxide of a metalloid is adjacent said transparent glass substrate, wherein said layer that is adjacent said transparent glass substrate comprises a surface that, prior to a coating of said surface, has an arithmetical mean height of the surface value, Sa, of at least 4.0 nm when tested in accordance with ISO 25178-2:2012, and wherein the coated glazing exhibits an average haze value of at least 0.47% when tested in accordance with ASTM D1003-13.

19. The coated glazing according to claim 18, wherein said layer based on an oxide of a metal is a layer based on SnO.sub.2, TiO.sub.2 or aluminium oxide, preferably SnO.sub.2, and wherein said layer based on an oxide of a metalloid is a layer based on SiO.sub.2 or silicon oxynitride, preferably SiO.sub.2.

20. The coated glazing according to claim 18, wherein both said layer based on an oxide of a metal and said layer based on an oxide of a metalloid are present, and wherein the transparent glass substrate is adjacent the layer based on an oxide of a metal and the layer based on an oxide of a metalloid is adjacent the further layer.

21. The coated glazing according to claim 18, wherein at least a portion of said layer that is adjacent said transparent glass substrate has a thickness of at least 35 nm, preferably at least 36 nm, more preferably at least 40 nm, most preferably at least 45 nm.

22. The coated glazing according to claim 18, wherein said further layer is a layer based on a transparent conductive oxide (TCO), wherein the TCO is one or more of fluorine doped tin oxide (SnO.sub.2:F), zinc oxide doped with aluminium, gallium or boron (ZnO:Al, ZnO:Ga, ZnO:B), indium oxide doped with tin (ITO), cadmium stannate, ITO:ZnO, ITO:Ti, In.sub.2O.sub.3, In.sub.2O.sub.3ZnO (IZO), In.sub.2O.sub.3:Ti, In.sub.2O.sub.3:Mo, In.sub.2O.sub.3:Ga, In.sub.2O.sub.3:W, In.sub.2O.sub.3:Zr, In.sub.2O.sub.3:Nb, In.sub.2-2xM.sub.xSn.sub.xO.sub.3 with M being Zn or Cu, ZnO:F, Zn.sub.0.9Mg.sub.0.1O:Ga, and (Zn,Mg)O:P, ITO:Fe, SnO.sub.2:Co, In.sub.2O.sub.3:Ni, In.sub.2O.sub.3:(Sn,Ni), ZnO:Mn, and ZnO:Co, preferably fluorine doped tin oxide (SnO.sub.2:F).

23. The coated glazing according to claim 18, wherein said layer that is adjacent said transparent glass substrate comprises a surface that, prior to a coating of said surface, has an arithmetical mean height of the surface value, Sa, of at least 4.5 nm, more preferably at least 5.0 nm, even more preferably at least 5.5 nm, even more preferably at least 6.0 nm, most preferably at least 6.5 nm.

24. The coated glazing according to claim 18, wherein the coated glazing comprises an outermost layer wherein said outermost layer comprises a surface that has an arithmetical mean height of the surface value, Sa, of at least 12.5 nm, preferably at least 13.5 nm, more preferably at least 14.5 nm, even more preferably at least 15.5 nm, most preferably at least 16.0 nm, but preferably at most 45 nm, more preferably at most 30 nm, even more preferably at most 25 nm, most preferably at most 21 nm.

25. The coated glazing according to claim 18, wherein the coated glazing exhibits an average haze value of at least 0.5%, preferably at least 0.6%, more preferably at least 0.7%, most preferably at least 0.8% when tested in accordance with ASTM D1003-13.

26. The coated glazing according to claim 18, wherein the coated glazing comprises, preferably consists of, at least the following layers in sequence: a transparent glass substrate, a layer based on an oxide of a metal that is a layer based on SnO.sub.2, a layer based on an oxide of a metalloid that is a layer based on SiO.sub.2, and a further layer that is a layer based on fluorine doped tin oxide (SnO.sub.2:F), wherein said layer that is adjacent said transparent glass substrate comprises a surface that, prior to a coating of said surface, has an arithmetical mean height of the surface value, Sa, of at least 4.5 nm when tested in accordance with ISO 25178-2:2012, and wherein the coated glazing exhibits an average haze value of at least 0.50% when tested in accordance with ASTM D1003-13.

27. A method of manufacture of a coated glazing according to claim 18, comprising the following steps in sequence: a) providing a transparent glass substrate, b) depositing at least the following layers in sequence directly or indirectly on a surface of the transparent glass substrate: i) a layer based on an oxide of a metal and/or a layer based on an oxide of a metalloid, and ii) a further layer.

28. The method according to claim 27, wherein step b) i) is carried out using Chemical Vapour Deposition (CVD), preferably wherein both steps b) i) and b) ii) are carried out using CVD.

29. The method according to claim 27, wherein step b) i) is carried out when the transparent glass substrate is at a temperature of at least 690 C., preferably at least 715 C., more preferably at least 725 C., most preferably at least 730 C.

30. The method according to claim 27, wherein said deposition of the layer based on an oxide of a metal in step b) i) is carried out when the transparent glass substrate is at a temperature of at least 690 C., preferably at least 715 C., more preferably at least 725 C., most preferably at least 730 C., but at most 790 C., preferably at most 760 C., more preferably at most 750 C., most preferably at most 745 C.

31. The method according to claim 27, wherein the method further comprises, following step b) ii), bending the coated glazing.

32. A coated glazing comprising at least the following layers in sequence: a transparent glass substrate, a layer based on an oxide of a metal and/or a layer based on an oxide of a metalloid, and a further layer, wherein either said layer based on an oxide of a metal or said layer based on an oxide of a metalloid is adjacent said transparent glass substrate, wherein the coated glazing comprises an outermost layer wherein said outermost layer comprises a surface that has an arithmetical mean height of the surface value, Sa, of at least 12.5 nm when tested in accordance with ISO 25178-2:2012, and wherein the coated glazing exhibits an average haze value of at least 0.47% when tested in accordance with ASTM D1003-13.

Description

[0075] 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 drawings in which:

[0076] FIG. 1 is a schematic view, in cross-section, of a coated glazing in accordance with certain embodiments of the present invention;

[0077] FIG. 2 is a schematic view, in cross-section, of a bent coated glazing in accordance with certain embodiments of the present invention;

[0078] FIG. 3 is a schematic plan view of the bent coated glazing shown in FIG. 2;

[0079] FIG. 4 is a schematic view, in vertical section, of an installation for practicing the float glass process which incorporates several CVD apparatuses for manufacturing a coated glazing in accordance with certain embodiments of the present invention;

[0080] FIG. 5 is a photograph of Comparative Example 1 coated glazing that has been bent and tested for humidity resistance;

[0081] FIG. 6 is a photograph of Example 6 coated glazing of the present invention that has been bent and tested for humidity resistance;

[0082] FIG. 7 is a photograph of Comparative Example 2 coated glazing that has been bent and tested for humidity resistance; and

[0083] FIGS. 8-12 are respectively photographs of Examples 10-14 coated glazings of the present invention that have been bent and tested for humidity resistance.

[0084] 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 SnO.sub.2 3, a layer based on SiO.sub.2 4 and a layer based on fluorine doped tin oxide (SnO.sub.2:F) 5.

[0085] FIG. 2 depicts a cross-section of a bent coated glazing 6 in accordance with certain embodiments of the present invention. Bent coated glazing 6 has the same structure as coated glazing 1 shown in FIG. 1 but bent coated glazing 6 has subsequently been bent in a press bending process to achieve a curved right angle. FIG. 3 shows that bent coated glazing 6 has a rectangular outline when observed in plan view.

[0086] As discussed above, the CVD process may be carried out in conjunction with the manufacture of the glass substrate in the float glass process. The float glass process is typically carried out utilizing a float glass installation such as the installation 10 depicted in FIG. 4. However, it should be understood that the float glass installation 10 described herein is only illustrative of such installations.

[0087] As illustrated in FIG. 4, the float glass installation 10 may comprise a canal section 20 along which molten glass 19 is delivered from a melting furnace, to a float bath section 11 wherein the glass substrate is formed. In this embodiment, the glass substrate will be referred to as a glass ribbon 8. However, it should be appreciated that the glass substrate is not limited to being a glass ribbon. The glass ribbon 8 advances from the bath section 11 through an adjacent annealing lehr 12 and a cooling section 13. The float bath section 11 includes: a bottom section 14 within which a bath of molten tin 15 is contained, a roof 16, opposite side walls (not depicted) and end walls 17. The roof 16, side walls and end walls 17 together define an enclosure 18 in which a non-oxidizing atmosphere is maintained to prevent oxidation of the molten tin 15.

[0088] In operation, the molten glass 19 flows along the canal 20 beneath a regulating tweel 21 and downwardly onto the surface of the tin bath 15 in controlled amounts. On the molten tin surface, the molten glass 19 spreads laterally under the influence of gravity and surface tension, as well as certain mechanical influences, and it is advanced across the tin bath 15 to form the glass ribbon 8. The glass ribbon 8 is removed from the bath section 11 over lift out rolls 22 and is thereafter conveyed through the annealing lehr 12 and the cooling section 13 on aligned rolls. The deposition of coatings preferably takes place in the float bath section 11, although it may be possible for deposition to take place further along the glass production line, for example, in the gap 28 between the float bath 11 and the annealing lehr 12, or in the annealing lehr 12.

[0089] As illustrated in FIG. 4, four CVD apparatuses 9, 9A, 9B, 9C are shown within the float bath section 11. Thus, depending on the frequency and thickness of the coating layers required it may be desirable to use some or all of the CVD apparatuses 9, 9A, 9B, 9C. One or more additional coating apparatuses (not depicted) may be provided. One or more CVD apparatus may alternatively or additionally be located in the lehr gap 28. Any by-products are removed through coater extraction slots and then through a pollution control plant. For example, in an embodiment, a tin oxide coating is formed utilizing using CVD apparatus 9A, a silica coating is formed utilizing CVD apparatus 9, and adjacent apparatuses 9B and 9C are utilized to form a fluorine doped tin oxide coating.

[0090] A suitable non-oxidizing atmosphere, generally nitrogen or a mixture of nitrogen and hydrogen in which nitrogen predominates, is maintained in the float bath section 11 to prevent oxidation of the molten tin 15 comprising the float bath. The atmosphere gas is admitted through conduits 23 operably coupled to a distribution manifold 24. The non-oxidizing gas is introduced at a rate sufficient to compensate for normal losses and maintain a slight positive pressure, on the order of between about 0.001 and about 0.01 atmosphere above ambient atmospheric pressure, so as to prevent infiltration of outside atmosphere. For the purposes of describing the invention, the above-noted pressure range is considered to constitute normal atmospheric pressure.

[0091] The CVD of coating layers is generally performed at essentially atmospheric pressure. Thus, the pressure of the float bath section 11, annealing lehr 12, and/or in the gap 28 between the float bath 11 and the annealing lehr 12 may be essentially atmospheric pressure. Heat for maintaining the desired temperature regime in the float bath section 11 and the enclosure 18 is provided by radiant heaters 25 within the enclosure 18. The atmosphere within the lehr 12 is typically atmospheric air, as the cooling section 13 is not enclosed and the glass ribbon 8 is therefore open to the ambient atmosphere. The glass ribbon 8 is subsequently allowed to cool to ambient temperature. To cool the glass ribbon 8, ambient air may be directed against the glass ribbon 8 by fans 26 in the cooling section 13. Heaters (not shown) may also be provided within the annealing lehr 12 for causing the temperature of the glass ribbon 8 to be gradually reduced in accordance with a predetermined regime as it is conveyed therethrough.

EXAMPLES

Thickness and Haze Measurements of Coated Glazings

[0092] All layer depositions were carried out using CVD. All Examples shown in Table 1 below were produced on a float line using a 4 mm soda-lime-silica glass substrate. Comparative Examples 1-3 were coated at an average line speed of 13.3 m/min, while Examples 4-6 were coated at an average line speed of 8.3 m/min. The deposition of the base layer of SnO.sub.2 was carried out at a glass temperature of 700 C. for Comparative Examples 1-3 and 720 C. for Examples 4-6.

[0093] A SnO.sub.2 layer was deposited over the glass surface using a single coater with the following components: [0094] N.sub.2 carrier gas, O.sub.2, dimethyltin dichloride, and H.sub.2O.

[0095] A SiO.sub.2 layer was deposited over the glass surface using a single coater with the following components: [0096] N.sub.2 carrier gas, He carrier gas, O.sub.2, C.sub.2H.sub.4, and SiH.sub.4.

[0097] A SnO.sub.2:F layer was deposited over the glass surface using two coaters for each of Comparative Examples 1-3 and Examples 4-6 with the following components: [0098] N.sub.2 carrier gas, O.sub.2, dimethyltin dichloride, HF, and H.sub.2O.

[0099] The layer thicknesses of the Examples were determined by SEM. The haze values of the Examples were measured in accordance with the ASTM D1003-13 standard using a BYK-Gardner Hazemeter.

TABLE-US-00001 TABLE 1 Layer thicknesses and haze values for Comparative Examples and Examples of the present invention. SnO.sub.2 layer SiO.sub.2 layer SnO.sub.2:F layer Average thickness thickness thickness Haze Example (nm) (nm) (nm) (%) Comparative 34 22 372 0.45 Example 1 Comparative 34 22 372 0.45 Example 2 Comparative 34 22 372 0.46 Example 3 Example 4 36 22 359 0.62 Example 5 36 19 325 0.56 Example 6 40 22 341 0.57

Press Bending and Humidity Testing of Coated Glazings

[0100] All of the above Examples were then press bent to produce bent coated glazings with a low radius of curvature (<600 mm). Each Example was prepared for bending by cutting to size (approximately 550550 mm) and edge working the cut edges (to reduce their sharpness (for safety reasons), to generally reduce the risk of fracture originating from the edge, and/or for aesthetic reasons). The edge working was an abrasive machining process involving edge-grinding and/or polishing. The Example was then washed and a heating furnace was used to heat each Example from room temperature to >600 C. With the coating on the concave side of the prospective shape, each Example was then press bent to achieve the same curvature. The Examples were then toughened by an air quenching step.

[0101] Next the resistance of the bent Examples to humidity was tested. The bent Examples were exposed to humid, ambient conditions (exposure to 95% relative humidity (rh), at 40 C., for >7 days) using a humidity cabinet and the incidence of cohesive failure within the coating was observed. In every case Comparative Examples 1-3 suffered greater incidences of cohesive failure than Examples 4-6 of the present invention. FIG. 5 shows a photograph of Comparative Example 1 after the humidity test. The areas of cohesive failure have been marked with a black pen and are clearly visible as paler regions. The observed cohesive failure generally occurred at the interface between the SiO.sub.2 and SnO.sub.2:F layers. In contrast, the Examples of the present invention exhibited very little cohesive failure within the coating after the humidity test, as shown in the photograph of Example 6 in FIG. 6 which shows a very small patch of cohesive failure in the bend.

Analysis of Surface Topography of Coated Glazings

[0102] Three further sets of Examples (7a-7c, 8a-8c and 9a-9c) of coated glazings were prepared, in order to investigate the surface topography of the layers. Examples 7a, 8a and 9a were coated with a base layer of SnO.sub.2 only. Examples 7b, 8b and 9b were coated with a base layer of SnO.sub.2 and a top layer of SiO.sub.2. Examples 7c, 8c and 9c were coated with a base layer of SnO.sub.2, a middle layer of SiO.sub.2 and a top layer of SnO.sub.2:F. Examples 7a-7c, 8a-8c and 9a-9c were prepared in the same manner as Comparative Examples 1-3 and Examples 4-6 (except Examples 7a-b, 8a-b and 9a-b were coated with fewer layers before they were analysed). In addition, the deposition of the base layer of SnO.sub.2 was carried out at a glass temperature of 720 C. for Examples 7a-c and at a glass temperature of 735 C. for Examples 8a-c and 9a-c. Also, immediately prior to the deposition of the top layer of SnO.sub.2:F in Example 8c the coated glazing was cooled to test the effect on roughness and haze.

[0103] Examples 7a-7c, 8a-8c and 9a-9c were then analysed by atomic force microscopy (AFM) and the haze values of Examples 7c, 8c and 9c were measured in accordance with the ASTM D1003-13 standard using a BYK-Gardner Hazemeter.

[0104] For the AFM a small section (approximately 4 cm.sup.2) of coated glass was removed from each of the Examples. In order to eliminate any superficial contamination from the coated surfaces, the Examples were cleaned by sonicating in methanol for approximately 60 seconds, and dried with a compressed gas duster. Following cleaning, the Examples were placed directly onto the AFM instrument stage, and secured to the stage using the instrument's internal vacuum system, in readiness for analysis.

[0105] Atomic Force Microscopy is a technique which uses a cantilever incorporating a small sharp tip (approximately 2-20 nm in radius) to physically measure surface topography in the nm height range and nm to m lateral range. AFM instruments are generally equipped with several modes of operation, of which the following are examples:

TappingMode

[0106] This is a mode in which the cantilever is oscillated at, or near to, its resonant frequency, lightly tapping the surface under investigation. The cantilever's oscillation amplitude changes with proximity to the sample surface, and the topography image is obtained by the system monitoring these changes. The TESPA AFM probes used for this technique have a nominal tip radius of 8 nm.

PeakForce Tapping with ScanAsyst (PFTSA)

[0107] An imaging technique in which the AFM cantilever is brought in and out of contact with the surface, oscillating at well below its resonant frequency. This mode performs a very fast force curve at every pixel in the image. The peak force of each of these curves is then used as the imaging feedback signal, providing direct force control. This allows it to operate at even lower forces than TappingMode, which helps protect delicate samples and tips.

[0108] ScanAsyst is a PFT variant which utilises intelligent algorithms to automatically optimise all imaging parameters. The SCANASYST-AIR probes used for this technique have a nominal tip radius of 2 nm.

[0109] The Examples were analysed over regions of 500500 nm, 11 m (twice), and 55 m. The 11 m and 55 m scans were undertaken with the Dimension Icon AFM in the Peak Force Tapping mode of operation, incorporating ScanAsyst (PFTSA). This mode of imaging uses a probe consisting of a silicon nitride cantilever with a silicon tip (radius2 nm), which is smaller than the tips used in conventional Tapping Mode (tip radius8 nm). The 500500 nm scans were undertaken using soft Tapping Mode. PFTSA images were collected as height sensor and peak force error simultaneously, whereas the Tapping Mode images were acquired as height sensor and amplitude error.

Data Analysis

[0110] NanoScope Analysis version 1.40 software was employed to flatten the raw data (to remove sample tilt) and analyse the data for the following 3D areal roughness parameter: [0111] Saarithmetical mean heightExpresses the difference in height of each point compared to the arithmetical mean of the surface. This parameter is used generally to evaluate surface roughness.

[0112] Sa was measured in accordance with ISO 25178-2:2012 Geometrical product specifications (GPS)Surface texture: ArealPart 2: Terms, definitions and surface texture parameters. An average was taken of the four Sa values for each Example.

TABLE-US-00002 TABLE 2 Average Sa and average haze for a number of Examples Glass/SnO.sub.2 Glass/SnO.sub.2/SiO.sub.2 Glass/SnO.sub.2/ Glass/SnO.sub.2/ Average Average Sa SiO.sub.2/SnO.sub.2:F SiO.sub.2/SnO.sub.2:F Sa (nm) (nm) Average Sa (nm) Average Haze (%) Example 7a Example 7b Example 7c Example 7c 5.6 4.6 14.0 0.52 Example 8a Example 8b Example 8c Example 8c 6.4 5.5 14.9 0.70 Example 9a Example 9b Example 9c Example 9c Not Tested Not Tested 16.0 0.90

[0113] Table 2 shows that Example 8a has a rougher base layer surface than that of Example 7a which it is postulated is due to the higher glass substrate temperature employed with Example 8a. As detailed above, the roughness of the base layer largely dictates the roughness of subsequently deposited layers, although it is worth noting that the cooling carried out prior to the deposition of the top layer in Example 8c resulted in a lower roughness than was obtained without cooling with Example 9c. Table 2 also shows that there is a strong correlation between the roughness of the stack and the haze it exhibits.

Further Press Bending and Humidity Testing of Coated Glazings

[0114] Five further Examples (10-14) were prepared in the same way as Examples 4-6 detailed above. Examples 10-14 were press bent and humidity tested in the same way as Comparative Examples 1-3 and Examples 4-6 detailed above. All of Examples 10-14 had a base layer of SnO.sub.2 that is at least 35 nm thick.

[0115] Average haze and Sa values of Comparative Examples 1 and 2 and Examples 10-14 were determined in the same way as detailed above and are shown in Table 3 below. For the Sa values an average was taken of the four values measured for the three different scan sizes detailed above in relation to Examples 7a-7c, 8a-8c and 9a-9c. The Sa values represent the arithmetical mean height of the surface of the top layer of SnO.sub.2:F for each example. A cohesive failure rating of 0-10 was assigned to each example following the humidity testing, with 0 representing no cohesive failure and gradually increasing to 10 representing complete cohesive failure.

TABLE-US-00003 TABLE 3 Average haze, Average Sa and cohesive failure ratings for Comparative Examples and Examples of the present invention Average Haze Average Sa Cohesive Failure Example (%) (nm) Rating Comparative Example 1 0.45 12.7 9 Comparative Example 2 0.45 13 8 Example 10 0.66 12.8 3 Example 11 0.92 16.1 1 Example 12 1.11 17.4 1 Example 13 1.18 17.2 2 Example 14 0.62 15.8 4

[0116] As detailed above, FIG. 5 shows a photograph of Comparative Example 1 after the humidity test. Photographs of Comparative Example 2 and Examples 10-14 after the humidity test are shown in FIGS. 7-12 respectively. As will be noted from Table 3 and the associated figures, in general the cohesive failure rating is inversely proportional to the average haze and the average Sa of the surface of the top layer of SnO.sub.2:F, which of course largely arises from the roughness of the base layer of SnO.sub.2. While an acceptable cohesive failure rating can be achieved at a lower average Sa, an Sa of at least 16 nm is required to achieve the best cohesive failure performance.

[0117] 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.