Patent Application
20240253330
This invention relates to an insulating glass (IG) window unit designed to prevent or reduce bird collisions therewith. The IG unit includes at least first and second substrates, spaced apart from one another, wherein the first substrate is configured to face the exterior of a building, supports on its inwards facing surface a coating which reflects ultraviolet (UV) radiation from the sun so that birds are capable of more easily seeing the window. By making the window more visible to birds, bird collisions and bird deaths can be reduced. The first substrate may in particular be laminated to a third substrate via a polymer-based laminating film (e.g., of or including PVB, EVA, or SGP). The provision of the laminated substrates in the IG window unit is particularly advantageous for bird friendly windows, because it can further reduce bird collisions by providing increased contrast ratio, improve durability, and improve processing.
Many buildings are provided with IG window units including glass substrates coated for example with a solar management coating (e.g., multi-layer coating for reflecting at least some infrared radiation) on an interior surface of one of the two substrates. Such IG units enable significant amounts of infrared (IR) radiation to be blocked so that it does not reach the interior of the building (apartment, house, office building, or the like).
Unfortunately, bird collisions with such windows represent a significant problem, in particular when those buildings are located in migratory bird paths. Birds flying along these paths repeatedly run into these buildings because they cannot see the windows of the building. This results in thousands of bird deaths, especially during seasons of bird migration. Birds living in environments such as forests or park areas, with buildings located in such areas, face similar problems associated with flying into the buildings.
Conventional ways of reducing bird collisions with windows include the use of nets, decals, or frit. However, these solutions are considered ineffective because of the aesthetic impact on the architecture and/or because they do not work as they do not make the glass more visible to birds.
Alternately, US2009130349A1, WO2015183681A1 and WO2019055953A1 for example disclose IG window units for reducing bird collisions, comprising a UV reflecting first coating on the outwards facing surface of the first, outermost, substrate so as to maximize the degree of UV reflectance. While the performance regarding collisions appears satisfactory, the coating nevertheless is subjected to wear and tear by its exposure to weather and cleaning. Furthermore, even if the coating is designed to be mostly visible in the ultraviolet wavelength range, the coating is still noticeable to the naked human eye, in particular when it is applied in a pattern.
Thus, there is room for improvement. In view of the above, it will be appreciated that there exists in particular a need in the art for improved windows which can prevent or reduce bird collisions therewith and which shows improved durability.
The present invention concerns, in certain embodiments, a window designed to prevent or reduce bird collisions therewith. The window may be an insulating glazing window unit. The window comprises at least first and second substrates, spaced apart from one another, wherein the first substrate is configured to face the exterior of a building and supports on its inwards facing surface a first coating which reflects ultraviolet (UV) radiation from the sun so that birds are capable of more easily seeing the window. The UV reflecting first coating comprises at least first, second, and third layers in this order moving away from the glass substrate, and wherein the first and third layers comprise a dielectric material chosen among niobium oxide, titanium oxide, zirconium oxide, a mixed oxide of titanium and zirconium, or a mixed nitride of zirconium and silicon and the second layer comprises silicon oxide SiOx.
The inventors have found that such a window may prevent or reduce bird collisions therewith and that the UV reflecting first coating is protected from wear and tear and that it is less noticeable by the naked eye. In particular color changes upon changing viewing angles may be much less noticeable. In particular the use of materials such as niobium oxide, titanium oxide, zirconium oxide, mixed oxides of titanium and zirconium, mixed nitrides of zirconium and silicon, or silicon oxide SiOx enables the first coating to reach high UV light reflectance and low UV absorption
In an embodiment of the present invention the first substrate has an ultraviolet light transmittance (Tuv), measured according to standard EN410:2011 and in the uncoated state of the substrate of at least 70%, preferably of at least 80%, more preferably of at least 85%. This ultraviolet light transmittance level may be reached by adjusting the composition of the substrate as is well known in the art. Higher UV light transmittance leads to higher levels UV light reflected by the UV reflecting first coating to be visible by birds as less UV light is absorbed.
In an embodiment of the present invention the first layer may be from 3 to 30 nm thick, the second layer may be from 20 to 90 nm thick, and the third layer may be from 5 to 50 nm thick. Thicknesses within the present description are geometric, or physical thicknesses, not optical thicknesses, unless otherwise noted.
In an embodiment of the present invention the first substrate is a soda lime glass substrate comprising less than 0.04 percent by weight of iron oxide (expressed as Fe2O3), preferably less than 0.02 percent by weight and a redox ratio, measured as the ratio of iron in the ferrous state (expressed as FeO) to the total amount of iron (expressed as Fe2O3) of more than 0.4. In soda lime glass substrates, the iron oxide content was found to be responsible for a large part of the absorption of ultraviolet light.
In an embodiment of the present invention, in the UV reflecting first coating, the second layer comprises up to 20 at % of aluminium.
In an advantageous embodiment of the present invention, in the UV reflecting first coating, in addition to providing high UV light reflectance and low UV absorption when used in the UV reflecting first coating, like niobium oxide or zirconium oxide, the mixed oxides of titanium and zirconium and mixed nitrides of zirconium and silicon these materials, but not titanium oxide, may be submitted to heat treatment, such as tempering or bending, without being degraded, for example without increase of its haze level.
Advantageously, first and third layers according to the invention, for example comprising niobium oxide, titanium oxide, zirconium oxide, a mixed oxide of titanium and zirconium or a mixed nitride of zirconium and silicon, have an absorption coefficient k at a wavelength of 550 nm lower than 0.1, and a refractive index n at a wavelength of 550 nm comprised between 2.1 and 2.8. The first and third layers may have differing compositions or may consist of a single layer or of two or more layers of different composition chosen among the materials niobium oxide, titanium oxide, zirconium oxide, a mixed oxide of titanium and zirconium or a mixed nitride of zirconium and silicon. Niobium oxide, mixed oxide of titanium and zirconium, and mixed nitride of zirconium and silicon are generally preferred for their particular resistance to heat treatments. More preferably, the first and third layers each essentially consist(s) of Tix1Zry1Oz1 or of Six2Zry2Nz2.
In a particular, the third layer may comprise zirconium oxide if it is the last layer in the layer tack, where it has less influence on the temperability and still provides high mechanical durability during processing.
Tix1Zry1Oz1 (TZO) is a mixed oxide of titanium and zirconium, comprising at least 35% by weight of titanium oxide, preferably at least 40% by weight of titanium oxide, more preferably at least 50% of titanium oxide. The expression “layer essentially consisting of Tix1Zry1Oz1” is also understood to encompass layers doped with at least one other element and containing up to at most 10% by weight of this at least one other element, said doped layers having properties, in particular optical properties, that are practically no different from those of pure Tix1Zry1Oz1 layers (for example, layers deposited by cathode sputtering processes using a TiZr target containing up to 10% by weight Al).
Six2Zry2Nz2 (SZN), is a mixed nitride of silicon and zirconium, comprising an atomic ratio of Zr to the sum Si+Zr, y2/(x2+y2), which is between 10.0% and 40.0%, these values being incorporated, indeed even between 15.0% and 25.0%. The expression “layer essentially consisting of Six2Zry2Nz2” is also understood to encompass layers doped with at least one other element and containing up to at most 10% by weight of this at least one other element, said doped layers having properties, in particular optical properties, that are practically no different from those of pure Six2Zry2Nz2 layers (for example, layers deposited by cathode sputtering processes using a SiZr target containing up to 10% by weight Al).
Advantageously, the second layer, comprising SiOx, has an absorption coefficient k at a wavelength of 550 nm lower than 0.1, and a refractive index n at a wavelength of 550 nm lower than 1.9, preferably lower than 1.8, more preferably comprised between 1.4 and 1.8. Oxides of silicon are preferred for their particular resistance to heat treatments. More preferably, the second layer essentially consists of silicon oxide (SiOx, with x comprised between 1.6 and 2.1), still more preferably the second layer essentially consists of SiO2. The expression “layer essentially consisting of oxides of silicon” is also understood to encompass layers doped with at least one other element and containing up to at most 20% by weight of this at least one other element, said doped layers having dielectric properties that are practically no different from those of pure silicon oxide layers (for example, layers deposited by cathode sputtering processes using a SiAl target containing up to 20% by weight Al, for example 10% Al).
In certain less preferred embodiments, the second layer comprising SiOx comprises nitrogen at a N/O atomic ratio less than 10% nitrogen, more advantageously less than 5%, even more advantageously less than 1%. Indeed, the presence of nitrogen tends to increase the refractive index of the second layer and reduce the UV reflecting first coating's performances.
The inventors have found that a IG window unit of the present invention,
In certain advantageous embodiments of the present invention, the UV reflecting first coating is not part of a low emissivity (lowE) coating, in particular no transparent conductive oxide based lowE coating, and does not contain any IR reflecting layer of silver or gold.
In certain advantageous embodiments of the present invention, the UV reflecting first coating does not coating does not contain any UV absorbing layer.
In certain example embodiments, a functional coating, such as a low emissivity, insulating or solar control coating, is provided on at least one face of the second substrate.
n certain advantageous embodiments of the present invention, the UV reflecting first coating is patterned so that the UV reflecting first coating is not provided continuously across the entire first substrate.
The following information is used in the present invention:
The positioning of coatings in a multiple glazing unit may be given according to the usual sequential numbering of the faces of a glazing unit, face 1 being on the exterior of the building or vehicle and face 4 (in the case of a glazing unit comprising two substrates) or face 6 (in the case of a glazing unit comprising three glass substrates) on the interior.
For the sake of clarity, when using terms like “below”, “above”, “lower”, “upper”, “first” or “last” herein, it is always in the context of a sequence of layers in a coating starting from the glass substrate below, going upward, further away from the glass. Such sequences may comprise additional intermediate layers, in between the defined layers, except when a direct contact is specified. Terms like “outwards”, “inwards”, “outermost”, “innermost” designate an orientation or location in an insulating glazing window unit as it would be when installed in a building,
These and further aspects of the invention will be explained in greater detail by way of example and with reference to the accompanying drawings in which:
The Figures are not drawn to scale.
In certain embodiments, the IG window unit includes a third substrate spaced apart from and in between the first and second glass substrates, the first and third glass substrates being laminated to one another via a polymer-based laminating film, for example including polyvinyl butyrate (PVB), ethylvinyl acetate (EVA) or an ionoplast polymer such as for example Sentryglas™ from Kuraray.
In certain embodiments of the present invention, the third substrate, if present, is provided on its inwards facing side with a low emissivity coating, such as an insulating coating or a solar control coating.
In certain embodiments of the present invention, in the UV reflecting first coating, the first layer is in direct contact with the substrate and with the second layer and the third layer is in direct contact with the second layer. In certain particular embodiments, the UV reflecting first coating may comprise no other layer than the first, second and third layers, that is it consists of the first, second and third layers. It was found that this represents the most economical, UV reflecting first coating, that still showed acceptable UV reflecting performance.
In certain embodiments the UV reflecting first coating in the IG window unit of the present invention may comprise a fourth layer above the third layer, moving away from the glass substrate, wherein the fourth layer advantageously has an absorption coefficient k at a wavelength of 550 nm lower than 0.1, and a refractive index n at a wavelength of 550 nm lower than 1.9, preferably lower than 1.8, more preferably comprised between 1.4 and 1.8 and for example comprises silicon oxide SiOx. The resulting coated glass sheet was found to reflect at least 20% of UV radiation in at least a substantial part of the range from 315 nm to 390 nm and maintains this level of UV reflection after heat treatment. Furthermore the variations due to heat treatment in transmitted and reflected colors are very low. Advantageously, the first layer is in direct contact with the substrate and with the second layer and the third layer is in direct contact with the second layer and the fourth layer. The fourth layer may in certain embodiments described further below be in contact with
In certain embodiments the UV reflecting first coating in the IG window unit of the present invention may comprise a fourth above the third layer and a fifth layer above the fourth layer, moving away from the glass substrate, wherein the fourth layer advantageously has an absorption coefficient k at a wavelength of 550 nm lower than 0.1, and a refractive index n at a wavelength of 550 nm lower than 1.9, preferably lower than 1.8, more preferably comprised between 1.4 and 1.8 and for example comprises silicon oxide SiOx and wherein the fifth layer has an absorption coefficient k at a wavelength of 550 nm lower than 0.1, and a refractive index n at a wavelength of 550 nm comprised between 2.1 and 2.8 an for example comprises a dielectric material chosen among niobium oxide, titanium oxide, zirconium oxide, a mixed oxide of titanium and zirconium, or a mixed nitride of zirconium and silicon. Alternately, fifth layer may comprise niobium oxide and/or zirconium oxide. In particular, the fifth layer may comprise zirconium oxide if it is the last layer in the layer stack. The resulting coated glass sheet was found to reflect at least 40% of UV radiation in at least a substantial part of the range from 315 nm to 390 nm and maintains this level of UV reflection after heat treatment. Furthermore the variations due to heat treatment in transmitted and reflected colors are very low when a mixed oxide of titanium and zirconium, or a mixed nitride of zirconium and silicon and SiOx are used respectively for the fifth and fourth layers. Advantageously, the first layer is in direct contact with the substrate and with the second layer and the third layer is in direct contact with the second layer and the fourth layer and the fifth layer is in direct contact with the fourth layer.
In a particular, the fifth layer may comprise zirconium oxide if it is the last layer in the layer tack, where it has less influence on the temperability and still provides high mechanical durability during processing.
In certain embodiments the glass substrate coated with the UV reflecting first coating may have no haze noticeable by the human eye, even after optional heat treatment (tempering, bending), that is, as measured, a haze level after optional heat treatment of not more than 0.04%. This low haze, at least before heat treatment, may be obtained for example by depositing at least the first, third and fifth layers by magnetron sputtering. Coatings deposited by atmospheric pressure chemical vapor deposition on hot glass generally leads to higher roughness values and higher haze levels,
In certain embodiments, of the present invention the third, or the fourth, or the fifth layer may be the outermost layer of the coated glass sheet.
In certain example embodiments, there is provided a spacer or peripheral seal (10) is provided around the edge of the second substrate and the third substrate, if present, or around the edge of the second and the first substrate. The space between the second substrate and the third substrate, if present, or else the first substrate, may be evacuated to a pressure lower than atmospheric, forming a vacuum insulating glazing (VIG), and/or may be filled with a gas (e.g. Ar). An array of spacers (not shown) may be provided between the substrates in a viewing area of the window for spacing the substrates from one another as in the context of a VIG. The spacer(s) (10), other spacer(s), and/or peripheral seal space the two substrates (11 and 12) apart from one another so that the substrates do not contact one another and so that a space or gap (14) is defined therebetween. Alternatively, space (14) between the substrates (11, 12) need not be filled with a gas and/or need not be evacuated to a low pressure. In certain example embodiments, it is possible to suspend foil or other radiation reflective sheet(s) (not shown) in space (14). When substrate(s) (11 and/or 12) are of glass, each glass substrate may be of the soda-lime-silica type of glass, or any other suitable type of glass, and may be for example from 1 to 10 mm thick in certain example embodiments of this invention.
The IGU of
Still referring to
Still referring to
In certain example embodiments, the first substrate (11) with UV reflecting first coating (100) may block the transmission of at least 25% (more preferably at least 40%, more preferably at least 55%, even more preferably at least 60%, and possibly at least 65%) of UV radiation in at least a substantial part of the range from 315 nm to 390 nm.
The UV reflecting first coating (100) may be patterned (e.g., in the shape of a grid or in substantially parallel or non-parallel stripes) on the surface of substrate (1) as shown in
According to an embodiment of the present invention, the pattern may be such that each area coated with the complete first coating, has a surface area of 250 to 1500 mm2. Such area sizes may make the coated areas more recognizable for birds. For the avoidance of doubt, in patterned first coatings herewithin, areas coated with the complete first coating are continuous, or uninterrupted areas, that are surrounded by non-coated areas, unless where they reach the edges of the substrates.
According to an embodiment of the present invention, the pattern may be such that every area coated with the complete first coating, is distanced from the closest neighbouring area coated with the complete first coating by at least 30 mm, advantageously by at least 50 mm. In certain embodiments every area coated with the complete first coating, is distanced from the closest neighbouring area coated with the complete first coating by at up 150 mm, advantageously up to 120 mm, more advantageously up to 100 mm. Such distances may make the distinction between coated and non-coated area more distinguishable to birds.
The IG window unit may comprise, as shown in
As shown in
Functional coatings (101, 104) may comprise a transparent conductive oxide or comprise at least one functional, infrared reflecting, layer comprising silver, and include one or more layers, and in many embodiments it may be multilayer coating. Low-emissivity functional coatings (101, 104) for example includes at least one infrared (IR) reflecting layer (e.g., based on silver) sandwiched between at least first and second dielectric layers. Since one example function of low-emissivity coatings (101, 104) is to block (i.e., reflect and/or absorb) certain amounts of IR radiation and prevent the same from reaching the building interior, the solar management coatings (101, 104) may include at least one IR blocking (i.e., IR reflecting and/or absorbing) layer. Example IR blocking layer(s) which may be present in coatings (101, 104) are of or include silver (Ag), nickel-chrome (NiCr), gold (Au), and/or any other suitable material that blocks significant amounts of IR radiation. It will be appreciated by those skilled in the art that IR blocking layer(s) of low-E coating (101, 104) need not block all IR radiation, but only need to block significant amounts thereof. In certain embodiments, each IR blocking layer of coating (101, 104) is provided between at least a pair of dielectric layers. Example dielectric layers include silicon nitride, titanium oxide, silicon oxynitride, tin oxide, zinc stannate, and/or other types of metal-oxides and/or metal-nitrides. In certain embodiments, in addition to being between a pair of dielectric layers, each IR blocking layer may also be provided between a pair of contact layers of or including a material such as an oxide and/or nitride of nickel-chrome or any other suitable material. Example low-emissivity coatings (101, 104) which may be provided on substrates (12, 13) are described in Patents WO03106363A1, WO2004071984A1, WO2006048462A1, WO2009115595A1, WO2009115596A1, WO2009115599A1, WO2006048463A1, WO2006067102A1, WO2006122900A1, WO2007138097A1, WO2008113786A1, WO2011147875A1, WO2011147864A1, WO2013079400A1, WO2014191472A1, WO2014191474A1, WO2014191484A1, WO2014125081A1, WO2014125083A1, WO2014207171A1, all of which are hereby incorporated herein by reference. Of course, solar management coatings (101, 104) herein are not limited to these particular coatings, and any other suitable solar management coatings capable of blocking amounts of IR radiation may instead be used. Solar management coatings (101, 104) herein may be deposited on substrate(s) (12) and/or (13) in any suitable manner, including but not limited to sputtering, vapor deposition, and/or any other suitable technique.
In a particular embodiment the first layer, the third layer, and the fifth layer, if present, are identically patterned so that the first layer, the third layer, and the fifth layer are not provided continuously across the entire coated glass sheet and so that the second layer and the fourth layer, if present, are provided over the entire coated glass sheet. Such a coating is easier to deposit if masks are used during deposition by sputtering. Furthermore, the second and fourth layers provide additional protection to the glass surface against chemical aggression.
It is indeed a particular advantage of the UV reflecting first coatings of the present invention they are substantially invisible to human eyes. This means that the color of the reflected light of a substrate with this is very close to the color of the reflected light of the substrate without this coating. The color coordinates a* and b* of the reflected light of the substrate with this coating, a*(coated) and b*(coated), are such that they are very close to the color coordinates of the reflected light of the substrate without this coating, a*(uncoated) and b*(uncoated). In particular a*(coated) and b*(coated) may be such that a*(uncoated)−1<a*(coated)<a*(uncoated)+1 and b*(uncoated)−1<b*(coated)<b*(uncoated)+1.5. The substrate may bear a coating on the opposite side to the UV reflecting first coating and/or be part of a multiple glazing, in which cases the same applies.
As shown in
In certain example embodiments, similar to embodiments illustrated by
In the embodiments illustrated by
In certain example embodiments of this invention illustrated by
In the embodiments illustrated by
In certain example embodiments of this invention illustrated by
In the embodiments illustrated by
In certain example embodiments of this invention illustrated by
The layers (2-6) of the UV reflecting first coating (100a,b,c) are preferably deposited by sputtering in example embodiments of this invention. For example, layers comprising an oxide of titanium (6) or layers comprising a mixed oxide of titanium and zirconium, or a mixed nitride of zirconium and silicon (2,4,6) may be sputter deposited via at least one metallic target of titanium, titanium-zirconium alloy or zirconium-silicon alloy respectively, via sputtering in an atmosphere including a mixture of argon and reactive oxygen gases or of argon and reactive nitrogen respectively. And for example, layers comprising silicon oxide SiOx (3,5) may be sputter deposited via at least one sputtering target of or including Si or SiAl, via sputtering in an atmosphere including a mixture of argon and reactive oxygen gases. Rotating C-Mag sputtering targets, or other types of targets, may be used. In sputtering operations, sufficient reactive oxygen or nitrogen gas may be used to achieve the refractive index values discussed herein. Ceramic targets may alternatively be used to sputter deposit one or more of these layers. While the layers of the UV reflecting first coating (100a,b,c) are preferably deposited via sputtering, it is possible that they may be deposited via other techniques in alternative embodiments of this invention. In particular layers comprising SiOx (3,5) may be deposited by plasma enhanced chemical vapor deposition (PECVD), in particular hollow cathode PECVD.
The present invention further concerns an insulated glazing unit (IGU) comprising a coated glass substrate according to any one of the embodiments of this invention described above.
In example embodiments of this invention, there is provided an IGU comprising:
In the IGU of the immediately preceding paragraph, the UV reflecting first coating may reflect at least 20% of UV radiation in the whole range from 315 nm to 390 nm and may reflect on average 25% in the range from 315 nm to 390 nm. Additionally, the IGU of the immediately preceding paragraph, the UV reflecting first coating may reduce the transmittance of UV radiation by at least 15% in the whole range from 315 to 390 nm and may reduce the average transmittance of UV radiation by at least 20% in the range from 315 nm to 390 nm.
In a window of the present invention, in particular in the IGU of any of the preceding two paragraphs, the UV reflecting first coating may reflect at least 20% of UV radiation in the whole range from 315 nm to 390 nm and may reflect on average 25% in the range from 315 nm to 390 nm. Additionally, the IGU of the immediately preceding paragraph, the UV reflecting first coating may reduce the transmittance of UV radiation the whole range from 315 nm to 390 nm by at least 15% and may reduce the average transmittance of UV radiation by at least 40% in the range from 315 nm to 390 nm. This is in particular achieved when the UV reflecting first coating includes, in sequence starting from the glass substrate, first and third layers that comprise a dielectric material chosen among a mixed oxide of titanium and zirconium, or a mixed nitride of zirconium and silicon and second and fourth layers comprising SiOx.
In the IGU of any of the preceding three paragraphs, the UV reflecting first coating may reflect at least 25% of UV radiation in the whole range from 315 nm to 390 nm and may reflect on average 40% in the range from 315 nm to 390 nm. Additionally, the IGU of the immediately preceding paragraph, the UV reflecting first coating may reduce the transmittance of UV radiation in the whole range from 315 nm to 390 nm by at least 25% and may reduce the average transmittance of UV radiation by at least 50% in the range from 315 nm to 390 nm. This performance is in particular achieved when the UV reflecting first coating includes, in sequence starting from the glass substrate, first and third layers that comprise a dielectric material chosen among a mixed oxide of titanium and zirconium, or a mixed nitride of zirconium and silicon, fifth layer that may comprise an oxide of titanium, or a mixed oxide of titanium and zirconium, or a mixed nitride of zirconium and silicon and second and fourth layers comprising SiOx.
In the IGU of any of the preceding four paragraphs, the low-E coating may comprise first and second IR blocking layers each comprising Ag, at least one dielectric layer provided between the first IR blocking layer and the first substrate, at least another dielectric layer provided between the first and second IR blocking layers, and wherein the low-E coating supported by the first substrate has an emissivity (En) of no greater than 0.10 and/or a sheet resistance (Rs) of no greater than 8 ohms/square.
In the IGU of any of the preceding five paragraphs, the first and second glass substrates may be spaced apart from one another by at least one spacer and/or edge seal so as to define a space between the substrates. The space between the substrates may be filled with a gas and/or is evacuated to a pressure less than atmospheric.
In the IGU of any of the preceding six paragraphs, the first glass substrate coated with the UV reflecting first coating and with the low-emissivity coating may have no measurable haze level after optional heat treatment, that is, as measured, a haze level after optional heat treatment of not more than 0.04%.
The invention is not limited to the substrate being a glazing in a building. For example, the substrate may be a door, a balcony, a spandrel, or a part of any of these.
The present invention in certain embodiments concerns the following items:
In the following examples were all layers were deposited using magnetron sputtering on 4 mm thick normal clear soda lime glass. Example 1, 2, and 3 are according to the present invention. Example 4 is a comparative example, similar to Example 2 but with TiOx in stead of TZO. Table 1 below indicates the materials of the different layers and their physical thickness. TZO denotes a mixed oxide of titanium and zirconium mixed oxide which comprises 65% by weight of titanium oxide and 35% by weight of zirconium oxide. TiOx denotes an oxide of titanium with x comprised between 1.8 and 2.2.
Optical properties were determined for double glazing units comprising one example glass sheet and one uncoated 4 mm thick clear soda lime glass sheets separated by a 16 mm wide gap which is filled with an argon/air mixture comprising 90% by volume of argon, with one of the sheets being the respective examples above. Table 2 below shows the optical performances in a double glazing IGU obtained without heat treatment of the substrate bearing the UV reflecting first coating. The UV reflectance in the range from 315 nm to 390 nm is always determined on the uncoated side, which is the side that faces outwards on a building, of the first substrate of the IGU. The first substrate is bearing the UV reflecting first coating on the inwards facing side. The Transmittance Reduction in the range from 315 nm to 390 nm is the transmittance difference between an IGU without any coating and the IGUs made with the respective example coated glass sheets.
Examples 1, 2, 3, and 4 were submitted to a heat treatment in a static furnace at 670° C. for a duration of four minutes. Examples 1, 2, and 3 show essentially the same optical properties after this heat treatment as before. In addition on these samples the haze level before heat treatment and after heat treatment was below 0.1%. ΔE* of transmitted and reflected colors, due to the heat treatment were less than 5. On Example 4 the optical properties are modified upon heat treatment and in particular the haze level rises far above the initial 0.1% and is visible by the naked eye.
It should be noted that the minimum reflectance and minimum transmittance reduction in samples 1 and 2 is very similar, despite that example 1 has one layer less and that a notable improvement is obtained when a layer comprising five layers such as in example 3 is used.
The invention is not limited to the substrate being a glazing in a building. For example, the substrate is a door, a balcony, a spandrel.
| Number | Date | Country | Kind |
|---|---|---|---|
| 21187909.3 | Jul 2021 | EP | regional |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2022/070340 | 7/20/2022 | WO |
