Coated article having a low-E coating

Abstract

The present disclosure relates to coated articles having a low-E coating and methods for their preparation. The coated articles include a low-E coating supported by a substrate and comprising a metallic IR reflective layer, a protective layer in contact with the metallic IR reflective layer, and a dielectric layer.

Description

Technical Field

[0001] Priority Documents This application claims priority to Australian Provisional Patent Application No. 2022901475, entitled "COATED ARTICLES WITH A LOW-E COATING AND / OR A HARD COAT", filed on May 31, 2022, the entire content of which is incorporated herein by reference.

[0002] The present disclosure generally relates to coated articles and methods for their preparation. In certain forms, the present disclosure relates to coated articles having a low-E coating and methods for their preparation.

Background Art

[0003] Low-emissivity (low-E) coatings include high thin film stacks that reflect solar infrared radiation and allow some visible light to pass through. Low-E coatings are useful in architectural glass, automotive windows, and solar collectors due to their excellent energy-saving performance. The ability of low-e articles (such as windows) to reflect solar infrared radiation significantly reduces the temperature inside buildings in summer and maintains the heat inside in winter, thus minimizing the use of air conditioning and heating systems, respectively. Additionally, their high transmittance in the visible range greatly contributes to reducing the need for artificial lighting during the day.

[0004] To achieve this combination of reflectivity and transmittance, low-E coatings typically include a conductive metal layer and a dielectric layer. In some situations, a multilayer system of dielectric material - silver - dielectric material is used, where the thin layer of silver (about 10 nm) reflects long-wavelength IR, and the dielectric layer protects the silver and provides an anti-reflection function. Common examples of dielectric materials include TiO2, SnO2, or ZnO, which are typically deposited by magnetron sputtering.

[0005] In the case of architectural windows, the most commonly used coatings are low-E coatings. These reflect heat due to their metal content, are highly transparent, but are made in a rather complex structure that usually contains more than 20 layers and 10 different materials, resulting in an expensive manufacturing process. Furthermore, commercially available low-E coatings typically suffer from durability problems due to corrosion in the IR reflecting layer, which is usually made of silver (Ag), and are therefore often placed in the cavity between the double-pane windows to protect against weathering.

[0006] Conventionally, in the automotive industry, glass plates with an adhesive window tint consisting of one or more PET sheets containing carbon, ceramic nanoparticles or dark dyes have been used to darken the windows and block IR radiation from the sun. However, these tints absorb rather than reflect IR radiation. This means that the absorbed radiation is re-radiated into the vehicle by conduction and convection and therefore does not protect the vehicle from heat. Furthermore, they exhibit a low visible transmittance for efficient heat blocking and are therefore not suitable for public transportation or the front windshield of vehicles.

[0007] Another drawback of existing low-E coatings is that the thin metal layer attenuates microwave and high-frequency signals, especially in the high-frequency range such as 5G wireless signals (600 MHz to 100 GHz). For example, if a vehicle is equipped with a metal-based low-E window, it acts as a Faraday cage, reflecting or dramatically attenuating useful electrical communication signals. With the evolution of wireless devices, it is also important to have strong and stable signal strength indoors. The attenuation of signals through objects is also measured by the shielding effect (SE). The shielding effect is defined as the logarithm of the ratio of the magnitude of the incident electric field to the magnitude of the transmitted electric field and is expressed in decibels (dB). 0 dB means no attenuation. For example, in public transportation, the current strategy for amplifying signals is the installation of repeater devices. However, this type of device only amplifies the selected frequency and needs to be replaced when the communication standard is changed. These are expensive and consume energy. Another option is the use of ultra-wideband antennas, but their performance depends on the mounting position on the vehicle body, and their efficiency can be drastically reduced depending on the distance between the metal window and the antenna. Antennas can also be integrated into heated windows. However, these only cover the FM / TV range (50 - 800 MHz). The latest integrated window antennas can cover 4G LTE signals and low-frequency 5G signals, but these also need to be replaced when the communication standard is changed.

[0008] Articles (e.g., windows and doors) having a low-E coating tend to be exposed to harsh and extreme conditions in actual use, and thus weather resistance, robustness, and durability are important. In situations where plastic substrates rather than glass substrates are used in the automotive, transportation, or construction industries, the substrates tend to turn yellow and may lose transparency upon UV exposure. To address these problems, plastic substrates (e.g., polycarbonate) are typically protected with a liquid-applied coating (resin), and the outermost layer is also typically a hard coating. For example, commercially available polycarbonate can have a primer resin and a hard coat applied thereon, and the primer acts as an adhesion layer between the hard coat and the bare polycarbonate substrate.

[0009] There is still a need for coated articles and methods of preparing them that can mitigate or reduce one or more of the above problems. In other words, it would be desirable for the coated article to have a simplified low-cost structure while maintaining a visible light transmittance and IR radiation reflectance equivalent to existing commercial products. Additionally or alternatively, it would be desirable for the coated article to have a lower attenuation of signal transmission at telecommunications frequencies. Additionally or alternatively, it would be desirable for the coated article to have improved durability, abrasion resistance, and weather resistance. SUMMARY OF THE INVENTION

[0010] According to a first aspect, there is provided a coated article comprising a low-E coating supported by a substrate, the low-E coating comprising a metallic IR reflecting layer, a protective layer in contact with the metallic IR reflecting layer, and a dielectric layer.

[0011] In some embodiments, the coated article has an emissivity ε of about 0.04 < ε < about 0.4, for example, about 0.04 < ε < about 0.3, and optionally about 0.04 < ε < about 0.2. In some further embodiments, the coated article has a visible transmittance of greater than about 60%, preferably greater than about 70%, more preferably greater than about 80%, and / or an IR reflectance of greater than about 60%, preferably greater than about 70%. In still further embodiments, the low-E coating supported by the substrate has a total thickness in the range of about 90 nm to about 120 nm.

[0012] In some embodiments, the metallic IR reflective layer comprises silver (Ag), gold (Au), copper (Cu), aluminum (Al), zinc (Zn), niobium (Nb), titanium nitride (TiN), Ag / Au alloy, Ag / Cu alloy, Ag / Al alloy, NbN x , NbCr, NbCrN x and / or NbZrO x . Silver (Ag), gold (Au) or copper (Cu) may be particularly suitable for the metallic IR reflective layer. In some further embodiments, the low-E coating comprises one metallic IR reflective layer. In still further embodiments, the metallic IR reflective layer has a thickness of about 5 nm to about 25 nm, preferably about 10 nm to about 20 nm.

[0013] In some embodiments, the protective layer in contact with the metallic IR reflective layer comprises nickel-chromium alloy (NiCr), NiCrN x , Ni, Cr, NiCrO x , NiCrO x N y , Ni x Ti y O z , CrN x , NiO x , Ti, TiO x , NbO x , ZnO, Al2O3 and / or ZnAlO x . The protective layer preferably comprises NiCr, NiCrN x, Ni or Cr may be particularly suitable. In some further embodiments, the metal IR reflective layer is sandwiched between two adjacent protective layers. In still further embodiments, the protective layer has a thickness of from about 1 nm to about 5 nm, preferably from about 2 nm to about 3 nm.

[0014] In some embodiments, the low-E coating comprises one or more dielectric layers. In some embodiments, the dielectric layer comprises one or more transparent materials selected from the group consisting of TiO2, Ta2O5, Nb2O5, ZrO2, ZnO, ZnS, ZnSe, HfO2, LaTiO3, Al2O3, La2O3, Y2O3, Gd2O3, Sc2O3, Si3N4, SiO2, LiF, MgF2, Na3AlF6, SnO2, indium tin oxide (ITO), Al-doped zinc oxide (AZO), Al-doped SiO2, WO3, SiAlO x N y and SiO x N y and one or more selected from the group consisting of SiO N. In some further embodiments, the dielectric layer comprises one or more materials selected from the group consisting of TiO2, Nb2O5 and Ta2O5. In some further embodiments, each of the dielectric layers has a thickness of from about 10 nm to about 45 nm, such as from about 25 nm to about 45 nm.

[0015] In some embodiments, the metal IR reflective layer is sandwiched between two adjacent protective layers, each of the protective layers comprises NiCr and has a thickness of less than about 5 nm, and the metal IR reflective layer comprises Ag and has a thickness of about 20 nm.

[0016] In some embodiments, the coated article includes a low-E coating supported by a substrate, and the low-E coating includes, in order from the substrate outward, a dielectric layer containing TiO2, a protective layer containing NiCr, a metallic IR reflecting layer containing Ag, a protective layer containing NiCr, and a dielectric layer containing TiO2. In some further embodiments, the coated article includes a low-E coating supported by a substrate, and the low-E coating includes, in order from the substrate outward, a dielectric layer of TiO2 that is about 25 nm to about 45 nm, a protective layer of NiCr that is less than about 5 nm, a metallic IR reflecting layer of Ag that is about 10 nm to about 20 nm, a protective layer of NiCr that is less than about 5 nm, and a dielectric layer of TiO2 that is about 25 nm to about 45 nm. In still further embodiments, the coated article includes a low-E coating supported directly by a substrate, and the low-E coating includes, in order from the substrate outward, a dielectric layer of TiO2 that is about 40 nm, a protective layer of NiCr(80 / 20) that is less than about 5 nm, a metallic IR reflecting layer of Ag that is about 20 nm, a protective layer of NiCr(80 / 20) that is less than about 5 nm, a dielectric layer of TiO2 that is about 40 nm, and a dielectric layer / adhesion layer of SiO2 or Al-doped SiO2 that is about 10 nm.

[0017] In some embodiments, the coated article includes a hard coat as the outermost layer. In some embodiments, the metallic IR reflecting layer includes a frequency selective surface configured to reduce attenuation of electrical communication frequency signal transmission.

[0018] In some embodiments, the substrate of the coated article is substantially made from a plastic or glass that can be flexible or rigid. In some specific embodiments, the plastic used for the substrate is selected from the group consisting of polycarbonate, polyethylene, polypropylene, polymethyl methacrylate, polystyrene, polyamide, polyester, polyester carbonate, polyethersulfone, polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyethylene terephthalate glycol (PETG), acrylonitrile butadiene styrene (ABS), acrylonitrile styrene acrylate (ASA), polymethyl methacrylate (PMMA), and polyetherimide. In some further embodiments, the glass used for the substrate is selected from the group consisting of borosilicate glass, flat glass, fused silica glass, and soda lime (float) glass. In a specific embodiment, the coated article has no airspace between plates, and the low-E coating is applied to at least a part of the surface of the substrate exposed to the use environment. In some further embodiments, the substrate for the coated article has a thickness of about 0.4 cm to about 0.5 cm.

[0019] In some embodiments, the coated article is selected from the group consisting of windows, doors, and windshield glass.

[0020] According to a second aspect, there is provided a method for preparing a coated article of the first aspect, the method comprising introducing a dielectric layer, a protective layer in contact with the metal IR reflective layer, and the metal IR reflective layer onto a substrate.

[0021] In some embodiments, the dielectric layer, the protective layer in contact with the metal IR reflective layer, and the metal IR reflective layer are introduced onto the substrate by magnetron sputtering deposition. In some further embodiments, the dielectric layer of TiO2 is deposited onto the substrate by sputtering Ti under 400 sccm of Ar and 35 sccm of O2 at a working pressure of 0.00595 mbar, the protective layer of NiCr is deposited onto the TiO2 dielectric layer by sputtering NiCr (80 wt% Ni, 20 wt% Cr) under 400 sccm of Ar at a working pressure of 0.00369 mbar, and the Ag metal IR reflective layer is deposited onto the NiCr protective layer by sputtering Ag under 400 sccm of Ar at a working pressure of 0.00369 mbar. In still further embodiments, the dielectric / adhesion layer of SiO2 or Al-doped SiO2 is deposited onto the TiO2 dielectric layer by sputtering Si or 5 wt% Al-doped Si under 400 sccm of Ar and 45 sccm of O2 at a working pressure of 5.1×10 -3 mbar.

[0022] According to a third aspect, there is provided the use of a coated article prepared according to the first aspect or in accordance with the second aspect in an automobile or a building.

[0023] Embodiments of the present invention will be described with reference to the accompanying drawings.

Brief Description of the Drawings

[0024]

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DETAILED DESCRIPTION OF THE INVENTION

[0025] Aspects of the present disclosure result from the inventors' research on multifunctional coated articles that can have a simple structure, be durable, visually transparent, be able to reflect thermal energy, be efficient for 5G communication, and be abrasion and weather resistant. The coated articles can be widely applied to automotive vehicles and buildings, such as glass windows for energy conservation and efficient signal transmission.

[0026] As used herein, the term "low emissivity (low-E)" refers to a surface condition that emits low levels of radiant heat energy and can have an emissivity value of about 0.04 < ε < about 0.4. This ε means that the coated article can reflect at least about 60% to a maximum of about 96% of the ultraviolet and infrared light incident thereon.

[0027] As used herein, the term "IR reflection" means the ability to reflect infrared (IR) radiation, particularly near-IR radiation and mid-IR radiation.

[0028] As used herein, the term "telecommunication frequency" includes signals from about 600 MHz to about 100 GHz, particularly signals for 5G communication that enable greater bandwidth, higher data rates, lower latency, and increased capacity on a network, but is not limited thereto.

[0029] The term "frequency selective surface (FSS)" refers to a periodic resonant pattern designed on a coating that selectively enables or prevents the transmission of electromagnetic waves. For this purpose, frequency selective surfaces are particularly used to reduce the attenuation of telecommunication frequency signal transmission.

[0030] As used herein, the term "unit cell" with respect to a frequency selective surface refers to the basic shape that forms a periodic pattern.

[0031] As used herein, the terms "oxide", "nitride", and "oxynitride" include various stoichiometries and, unless otherwise specified, include all possible stoichiometries.

[0032] In the chemical formula of the compounds disclosed herein, the symbols "x" or "y" indicate the number of atoms of the element.

[0033] Disclosed herein are coated articles comprising a low-E coating supported by a substrate, the low-E coating comprising a metallic IR reflecting layer, a protective layer in contact with the metallic IR reflecting layer, and a dielectric layer. The composition of the disclosed coated article can be selected to make it transparent, which may be desirable in the automotive, transportation, or construction industries.

[0034] For this purpose, a coated article comprising a low-E coating may have an emissivity ε of about 0.04 < ε < about 0.4. Further, the coated article may have a visible transmittance of greater than about 60%, preferably greater than about 70%, more preferably greater than about 80%, and / or an IR reflectivity of greater than about 60%, preferably greater than about 70%. The low-E coating may have a total thickness of about 90 nm to about 120 nm, for example 110 nm. The transmittance (%T) and reflectivity (%R) are measured by a Cary 5000 spectrophotometer (Agilent Technologies) between 380 nm and 3300 nm. The visible solar weighted transmittance (%T VIS ) and the IR solar weighted reflectivity (%R IR ) were calculated according to equations 1 and 2, respectively.

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[0035] The low-E coatings disclosed herein can be applied directly or indirectly onto a variety of substrates that can be substantially made from plastic or glass. When the coated article is used as a window in a building or a vehicle, the substrate is preferably transparent and can have desirable optical quality and impact resistance. The substrate may be colored (e.g., green, gray or blue). The plastic substrate used may be rigid or flexible. For example, the low-E coatings disclosed herein may be applied onto a flexible plastic substrate for window tinting. Examples of suitable plastic substrates include, but are not limited to, polycarbonate, polyethylene, polypropylene, polymethyl methacrylate, polystyrene, polyamide, polyester, polyester carbonate, polyethersulfone, polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyethylene terephthalate glycol (PETG), acrylonitrile butadiene styrene (ABS), acrylonitrile styrene acrylate (ASA), polymethyl methacrylate (PMMA) and polyetherimide. Examples of glass substrates include, but are not limited to, borosilicate glass, flat glass, fused silica glass, soda lime (float) glass. Rigid glass substrates are well known, but it is also possible for the glass substrate to be flexible, for example, Corning® Willow® Glass manufactured by Corning Inc., Corning, USA. Polycarbonate is a very robust plastic, naturally transparent and can be a preferred option for replacing glass. A suitable example is Makrolon® AR polycarbonate commercially available from Covestro Group. The substrates used can be of various thicknesses and can be about 0.4 cm to 0.5 cm thick.

[0036] It will be understood that the low-E coating may be applied to one or both sides of the substrate. In certain embodiments, in the case of a double-glazed window, the low-E coating is applied to the inside of each glass pane. Coated articles comprising the low-E coatings and hard coats disclosed herein advantageously have high abrasion and corrosion resistance, which enables the application of the low-E coating to at least a portion of the surface of the substrate exposed to the use environment and eliminates the need to dispose therebetween window glass panes. In other words, the coated article need not have a space between window glass panes. The low-E coating reduces the amount of solar heat passing through the coated article (e.g., window) and maintains the interior cooler without impairing the amount of visible light transmitted. When the internal thermal energy tries to escape to the colder exterior during winter, the low-E coating reflects the heat back inside, thereby reducing the radiative heat loss through the coated article. One or more layers within the low-E coating can be applied onto the substrate using methods known in the art. An example of such method is physical vapor deposition (PVD), which includes, but is not limited to, magnetron sputtering, electron beam evaporation, and thermal evaporation.

[0037] The low-E coating comprises one or more metallic IR reflecting layers. Generally, the metallic IR reflecting layers are silver (Ag), aluminum (Al), copper (Cu), zinc (Zn), niobium (Nb), titanium nitride (TiN), Ag / Au alloy, Ag / Cu alloy, Ag / Al alloy, NbN x , NbCr, NbCrN x , NbZrO xAnd / or may comprise or consist of any reflective metal such as gold (Au). Preferably, silver (Ag) is utilized for one or more metal IR reflective layers because it is relatively achromatic. The thickness of the metal IR reflective layer can be selected to achieve the desired reflection of IR radiation and visible transmittance. On the other hand, the reflective layer is expected to be thin enough to allow visible light to pass through in order to provide good transmittance. On the other hand, the emissivity of a metal IR reflective layer (such as an Ag layer) tends to decrease as the sheet resistance decreases. Therefore, in order to obtain a low emissivity, the sheet resistance of one or more IR reflective layers (such as an Ag layer) must be as low as possible, which means as thick as possible. A thicker IR reflective layer may be beneficial for thermal performance but may result in higher cost and longer time for fabricating the metal IR reflective layer. In use, the thickness of the IR reflective layer can be from about 5 nm to about 25 nm, more preferably from about 10 nm to about 20 nm. If desired, two or three metal IR reflective layers can be used. These are called double or triple reflective low-E coatings. The more reflective layers (e.g., Ag layers), the higher the visible transmittance and IR reflectance.

[0038] The metal IR reflective layer can be applied using methods known in the art including but not limited to magnetron sputtering deposition and thermal decomposition processes. In certain embodiments, the IR reflective layer may be sputtered (e.g., at about 3000 W) from a cathode of the required metal onto a protective layer or a dielectric layer on a substrate in an inert atmosphere. An IR reflective layer fabricated by magnetron sputtering deposition generally functions better with respect to solar control and reduction of heat transfer through windows than an IR reflective layer fabricated by a thermal decomposition process.

[0039] Apply various protective layers on each metal IR reflective layer to provide immediate protection against plasma attack when sputtering, for example, one or more dielectric layers thereon, or immediate protection from the diffusion of aggressive species such as O2, O, H2O, and Na + to each metal IR reflective layer. Also, the protective layer desirably has good adhesion to the metal IR reflective layer and allows good transmission of visible light. Metals, alloys, silicides, nitrides, or any other suitable material to achieve the desired effect can be used. For example, the protective layer includes, but is not limited to, nickel-chromium alloy (NiCr), NiCrO x 、NiCrN x 、NiCrO x N y 、Ni x Ti y O z 、Ni、Cr、CrN x 、NiO x 、Ti、TiO x 、NbO x 、ZnO、Al2O3、ZnAlO x or any combination thereof or may consist of them. Nickel-chromium alloy (NiCr) includes, but is not limited to, NiCr(80 / 20 wt%), NiCr(70 / 30 wt%), NiCr(60 / 40 wt%), and NiCr(50 / 50 wt%). In some situations, the protective layer can also function as an adhesion layer and / or a nucleation layer. For all embodiments herein, each protective layer can have a thickness in the range of about 1 nm to about 5 nm, preferably about 1 nm to about 3 nm or about 2 nm to about 3 nm. Thicker protective layers can contribute to durability. If the protective layer is too thin, it tends to be discontinuous and cannot cover the metal IR reflective layer, thus having no effect of providing sufficient protection. In some embodiments, it is preferable to have protective layers on both sides of the IR reflective layer. However, it is possible to have a protective layer on only one side of the IR reflective layer. In a preferred embodiment, the protective layer includes NiCr. More preferably, protective layers made of NiCr are provided on both sides of the IR reflective layer.

[0040] Known methods, such as sputtering deposition and thermal evaporation, can be used to apply a protective layer onto a substrate. When a protective layer of NiCr is used, the protective layer is preferably sputtered (e.g., at about 700 W) onto a metallic IR reflective layer and deposited, for example, from a DC (direct current) target. When a protective layer of ZnO is used, the protective layer can be fabricated by arc plasma deposition using an evaporated zinc source with a plasma containing stoichiometrically excessive oxygen.

[0041] The dielectric layer of the low-E coating serves an anti-reflection function and increases the transmittance of the entire coated article. It also provides protection to one or more layers beneath it. If necessary, the low-E coating may include one or more dielectric layers. In some embodiments, two or more consecutive dielectric layers are used.

[0042] The one or more dielectric materials used for the dielectric layer are not particularly limited. Most commonly used dielectric materials, such as oxides, nitrides, oxynitrides, or combinations thereof, can be considered for the purposes of the present disclosure. It is also possible to dope the dielectric material with a suitable material such as Al or stainless steel. Factors including the refractive index n, the transparent region, the availability of deposition methods, and cost-effectiveness can be considered when selecting a suitable dielectric material. Other considerations such as compatibility with other materials and thermal stability can also be determining factors. Materials suitable for the dielectric layer include TiO2, Ta2O5, Nb2O5, ZrO2, ZnO, ZnS, ZnSe, HfO2, LaTiO3, Al2O3, La2O3, Y2O3, Gd2O3, Sc2O3, Si3N4 and SiAlO x N y including SiO2, Al-doped SiO2, LiF, MgF2, Na3AlF6, SnO2, indium tin oxide (ITO), Al-doped zinc oxide (AZO), WO3, SiO x N yIt may include one or more selected from. For the purpose of high transmittance and refractive index, the protective layer preferably contains or consists of TiO2, Nb2O5 and / or Ta2O5. If desired, a dielectric layer of SiO2 or Al-doped SiO2 can also function as an adhesive layer.

[0043] Generally, the thickness of each dielectric layer is adjusted to reduce internal and external reflectance so that the light transmittance is high, for example, exceeding 60%. The thickness of each dielectric layer may vary from about 25 nm to about 45 nm. However, it is recommended that the thickness of each dielectric layer on the IR reflective layer be within the range of about 30 nm to about 40 nm.

[0044] The dielectric layers used herein can be deposited by methods known in the art such as high-frequency magnetron sputtering, DC magnetron sputtering, reactive pulsed magnetron sputtering, thermal evaporation, electron beam evaporation, ion beam sputtering, and atomic layer deposition. The choice of deposition method can depend on the material to be deposited and the expected optical properties. In some embodiments, when a dielectric layer containing TiO2 and / or a dielectric layer containing SiO2 is deposited, magnetron sputtering is employed (for example, about 3000 W or 3800 W for TiO2, about 2000 W for SiO2), and the layer is prepared by sputtering a Ti or Si target in oxygen.

[0045] In some embodiments, a metal IR reflective layer is sandwiched between two adjacent protective layers, each of the protective layers contains or consists of NiCr and has a thickness of less than about 5 nm, and the metal IR reflective layer contains or consists of Ag and has a thickness of about 20 nm.

[0046] In some embodiments, the coated article disclosed herein includes a low-E coating supported by a substrate, and the low-E coating includes, in order from the substrate outward, a dielectric layer comprising or consisting of TiO2, a protective layer comprising or consisting of NiCr, a metallic IR reflecting layer comprising or consisting of Ag, a protective layer comprising or consisting of NiCr, and a dielectric layer comprising or consisting of TiO2. If necessary, a dielectric layer / adhesion layer comprising or consisting of SiO2 or Al-doped SiO2 is added on the outermost TiO2-containing or TiO2-comprising dielectric layer further from the substrate.

[0047] More specifically, the coated article includes a low-E coating supported by a substrate, and the low-E coating may include, in order from the substrate outward, a dielectric layer of TiO2 that is about 25 nm to about 45 nm, a protective layer of NiCr that is less than about 5 nm, a metallic IR reflecting layer of Ag that is about 10 nm to about 20 nm, a protective layer of NiCr that is less than about 5 nm, and a dielectric layer of TiO2 that is about 25 nm to about 45 nm. In yet further embodiments, the coated article includes a low-E coating supported by a substrate, and the low-E coating includes, in order from the substrate outward, a dielectric layer of TiO2 that is about 40 nm, a protective layer of NiCr(80 / 20) that is less than about 5 nm, a metallic IR reflecting layer of Ag that is about 20 nm, a protective layer of NiCr(80 / 20) that is less than about 5 nm, and a dielectric layer of TiO2 that is about 40 nm. In yet further embodiments, the coated article includes a low-E coating directly supported by a substrate, and the low-E coating includes, in order from the substrate outward, a dielectric layer of TiO2 that is about 40 nm, a protective layer of NiCr(80 / 20) that is less than about 5 nm, a metallic IR reflecting layer of Ag that is about 20 nm, a protective layer of NiCr(80 / 20) that is less than about 5 nm, a dielectric layer of TiO2 that is about 40 nm, and a dielectric layer / adhesion layer of SiO2 or Al-doped SiO2 that is about 10 nm, or consists of them.

[0048] Frequency selective surfaces on metal IR reflective layers are used to enhance the transmission of electrical communication frequencies through coated articles. The frequency selective surface can have a periodic pattern such as a periodic triangular lattice, a periodic square lattice, a periodic hexagonal lattice, a periodic circular lattice, or a periodic kagome lattice (see Figure 3). Additionally or alternatively, the frequency selective surface may have an aperiodic pattern such as a Penrose tiling. The frequency selective characteristics can be adjusted by changing the geometric shape and geometric parameters (such as unit cell dimensions and aperture line widths) of the periodic pattern to achieve the desired signal transmission at a specific operating frequency. The frequency selective surface used for this purpose can advantageously reduce the attenuation of signal transmission at electrical communication frequencies from about 30 dB to about 1 dB compared to a coated article where the metal IR reflective layer does not carry the frequency selective surface.

[0049] As used herein, the unit cell dimension refers to the dimension of the unit cell that reflects periodicity, and the aperture line width means the width of the ablated path. Taking a periodic hexagonal lattice as an example, the unit cell dimension is represented by the length of the diagonal (see, for example, Figure 2). In the case of a periodic square lattice, the unit cell dimension is represented by the diagonal of the square. In the case of a periodic ring lattice, the unit cell dimension is represented by the diameter. Preferably, the aperture line width is small enough so that the optical contrast is not visible to the naked eye.

[0050] Frequency selective surfaces can be fabricated by laser etching. If necessary, laser scribed grids can be utilized in the fabrication. By way of example, a stack of substrate / dielectric layer / protective layer / metal IR reflective layer / protective layer is etched by a pulsed Nd:YAG laser, and then one or more other layers, such as another dielectric layer and an outermost hard coat, are grown over the protective layer. In some embodiments, a stack of substrate / dielectric layer / protective layer / metal IR reflective layer is laser etched to create a frequency selective surface. The laser parameters can be optimized to etch only the metal IR layer without reaching the substrate. Alternatively, photolithography may be considered to create the frequency selective surface. By ablating only a small percentage (e.g., 5% to 10% of the layer surface area) of the area of the IR reflective layer, the heat reflective properties and high transmittance of the coated article are maintained while allowing the passage of telecommunications frequencies.

[0051] In some embodiments, the periodic pattern of the frequency selective surface has a unit cell dimension of less than about 2 mm, such as less than 1 mm, and an aperture line width of from about 30 μm to about 60 μm, such as 50 μm. In a preferred embodiment, the periodic pattern of the frequency selective surface is a periodic hexagonal lattice. More preferably, the diagonal of the hexagon is about 0.5 mm and the aperture line width is about 50 μm.

[0052] The inventors have found that a hard coat can be provided as the outermost layer to protect the underlying layer in order to improve the durability of the coated article (particularly with respect to abrasion resistance and weather resistance). This enables the coated article to be applied to automotive, medical, and architectural uses. For this purpose, various abrasion-resistant hard coats based on polysiloxane may be considered, and they can typically be applied at a thickness of about 5 μm to about 6 μm. In some embodiments, the abrasion-resistant hard coat based on polysiloxane can be prepared from a thermosetting liquid polysiloxane nanocomposite hard coat resin containing silica nanoparticles such as CRYSTALCOAT™ MP-101 commercially available from SDC TECHNOLOGIES ASIA PACIFIC, PTE. LTD. If necessary, an adhesion layer may be applied on the low-E coating before applying the hard coat, and the adhesion layer can be made of materials known in the art, such as SiO2 or Al-doped SiO2. When an adhesion layer of SiO2 or Al-doped SiO2 is employed, the thickness of the adhesion layer can be about 10 nm to about 100 nm, preferably about 10 nm. The polysiloxane-based hard coat can be applied using the dip-coat method or the flow-coat method. In the case of dip coating, the substrate is coated before being thermally cured.

[0053] In the absence of a hard coat, a coated article including a low-E coating can be placed in the cavity of a multi-pane window so as to be isolated from the atmosphere.

[0054] One or more other layers may also be present in the coated article disclosed herein. In some situations, instead of a hard coat, the coated article includes, as the outermost layer, an overcoat made of, for example, SiO2 to achieve improved durability.

[0055] In some situations, the coated articles according to the present disclosure can effectively reflect infrared light or heat, pass 5G signals while being highly transparent, which makes the coated articles useful for windows such as in public transportation and buildings. Also, the coated articles according to the present disclosure can have a simplified design compared to existing commercially available products (in particular, in some situations, having a relatively small number of coating layers, about 5 to 7 layers). The coated articles according to the present disclosure enable the application of a low-E coating to at least a part of the surface of a substrate that is exposed to the use environment (i.e., facing the atmosphere), and can eliminate the need to dispose the low-E coating between glass plates.

Example

[0056] Fabrication of a Coated Polycarbonate Substrate with a Low-E Coating

[0057] The coated polycarbonate as shown in FIG. 1 is prepared by the following method.

[0058] The Makrolon AR polycarbonate (PC) substrate was washed with a detergent and a non-abrasive sponge, dried with compressed air, and plasma-cleaned in an Ar atmosphere for 2 minutes.

[0059] The deposition of TiO2, NiCr, Ag, and Al-doped SiO2 was carried out by a custom inline magnetron sputtering system. This system uses high-purity tubular sputtering targets (height 80 cm and diameter 7.5 cm) that rotate during deposition: Ti (purity 99.99 wt%), NiCr (80 wt% Ni, 20 wt% Cr), Si (5 wt% Al-doped), and Ag (purity 99.99 wt%). The pressure before deposition was 1.5×10 -6 mbar, and each target was pre-sputtered for 4 minutes.

[0060] First, 40 nm of TiO2 was deposited in poison mode using 400 sccm of Ar and 35 sccm of O2, giving a working pressure of 0.00595 mbar. The sputtering power was maintained at 3800 W and the carrier speed was 1.04 mm / second.

[0061] Next, NiCr less than 5 nm was deposited at 700 W with a working pressure of 0.00369 mbar (400 sccm of Ar) and a carrier speed of 39.4 mm / second.

[0062] On top of the NiCr, Ag (20 nm) was sputtered at 3000 W with the same working pressure of 0.00369 mbar and a carrier speed of 21.4 mm / second.

[0063] Again, NiCr (less than 5 nm), then TiO2 (40 nm) were grown on the patterned Ag using the previously defined conditions. 10 nm of Al-doped SiO2 was deposited in a similar poison mode using 400 sccm of Ar and 45 sccm of O2, giving a working pressure of 5.1×10 -3 mbar and a carrier speed of 16.4 mm / second at 2000 W.

[0064] Finally, the stack was dip-coated using a Qualtech QPI-168 dip coater with a transparent hardcoat resin CrystalCoat MP101 (SDC Technologies, solids content 32.5%) consisting of a siloxane matrix embedded with silica nanoparticles. A dipping speed of 500 mm / min was used to obtain a hardcoat thickness of 5 μm. After dipping, the sample was dried for 30 minutes and then cured in an oven at 130 °C for 1 hour. This process was carried out at a humidity of 25 - 45%.

[0065] Figure 8 shows that the resulting low-E coating has a visible transmittance of about 61% and an IR reflectance of about 64%. Compared with several commercially available low-E coatings, the low-E coating prepared herein not only has a simple low-cost structure, but also exhibits equivalent visible light transmittance and equivalent IR radiation reflectance. The visible transmittance and IR reflectance were analyzed using a UV-VIS-NIR spectrophotometer (Cary 5000) manufactured by Agilent Technologies Inc.

[0066] Durability - Abrasion and corrosion of the coated articles prepared above

[0067] For the low-E samples, abrasion tests such as the Bayer test and the Steel Wool test were conducted. The Steel Wool test was performed using a Sutherland® 2000™ Rub Tester manufactured by Danilee Co. In the Bayer test, a TABER® Oscillating Abrasion Tester (Model 6100) was used to evaluate the abrasion resistance against fine gravel. In these tests, the higher the abrasion rate, the higher the resistance of the sample. Both tests confirmed the suitability of the coated article as the first window surface due to its high abrasion resistance (Figure 4). After the tests, almost no visual changes were observed.

Table 1

[0068] The low-E stack was placed in a corrosion chamber for 1000 hours. After 1000 hours (the time required for commercially available automotive side mirrors), the low-E coating showed almost no change in appearance and provided the same transmittance value. Figure 5a) shows the results of the non-protected stack (without hard coat) after 24 hours and the protected stack after 1000 hours in the corrosion chamber.

[0069] Fabrication of a coated polycarbonate substrate comprising a low-E coating having a frequency selective surface on a metallic IR reflective layer

[0070] The Makrolon AR polycarbonate (PC) substrate was cleaned with a detergent and a non-abrasive sponge, dried with compressed air, and plasma-purified in an Ar atmosphere for 2 minutes.

[0071] The deposition of TiO2, NiCr, Ag, and Al-doped SiO2 was carried out by a custom in-line magnetron sputtering system. This system uses high-purity tubular sputtering targets (80 cm in height and 7.5 cm in diameter) that rotate during deposition: Ti (99.99 wt% purity), NiCr (80 wt% Ni, 20 wt% Cr), Si (5 wt% Al-doped), and Ag (99.99 wt% purity). The pressure before deposition was 1.5×10 -6 mbar, and each target was pre-sputtered for 4 minutes.

[0072] First, 40 nm of TiO2 was deposited in poison mode using 400 sccm of Ar and 35 sccm of O2 at a working pressure of 0.00595 mbar. The sputtering power was maintained at 3800 W, and the carrier speed was 1.04 mm / s.

[0073] Next, less than 5 nm of NiCr was deposited at 700 W at a working pressure of 0.00369 mbar (400 sccm of Ar) and a carrier speed of 39.4 mm / s.

[0074] On top of the NiCr, Ag (20 nm) was sputtered at 3000 W at the same working pressure of 0.00369 mbar and a carrier speed of 21.4 mm / s.

[0075] The frequency selective surface (FSS) is first designed by AutoCAD. The pattern design is saved as a drawing exchange format (DXF) file and then transferred to a laser ablation device. The periodic FSS hexagonal pattern (unit cell 0.5 mm) is ablated and evaporated from the Ag thin film by a Nd:YAG (1064 nm) pulsed laser G8 manufactured by Sei Laser. The pattern is etched at a frequency of 10 kHz at a speed of 100 mm / second and a power of 18 W. These parameters produce an ablation line width of 50 μm. An extraction system is attached to the machine to remove the fumes from the evaporation process.

[0076] Again, NiCr (less than 5 nm), and then TiO2 (40 nm), were grown on the patterned Ag using the previously defined conditions.

[0077] 10 nm of Al-doped SiO2 was deposited in a similar poisoning mode using 400 sccm of Ar and 45 sccm of O2 at a working pressure of 5.1x10 -3 mbar and a power of 2000 W. The carrier speed was 16.4 mm / second.

[0078] Finally, the stack was dip-coated with a transparent hard coat resin CrystalCoat MP101 (SDC Technologies, solids content 32.5%) consisting of a siloxane matrix embedded with silica nanoparticles using a Qualtech QPI-168 dip coater. A dipping speed of 500 mm / min was used to obtain a hard coat thickness of 5 μm. After dipping, the sample was dried for 30 minutes and then cured in an oven at 130 °C for 1 hour. This process was carried out at a humidity of 25 - 45%.

[0079] Characterization of a Coated Polycarbonate Substrate Containing a Low-E Coating with a Frequency Selective Surface on a Metallic IR Reflective Layer

[0080] Figure 7 and the following table provide the characteristics of the coated article having a frequency selective surface and are compared to a plain polycarbonate and a coated article without a frequency selective surface.

Table 2

[0081] The FSS technology has also been applied to fully grown low-E coatings (Figure 2). Before growing the top TiO2, Al-doped SiO2, and hard coat, the TiO2 / NiCr / Ag / NiCr film was laser etched in a hexagonal pattern. The transmittance of the resulting low-E coating hardly changed, and the blocked IR light decreased by only 10% (Figure 8).

[0082] Any reference in this specification to prior art is not an admission or any form of suggestion that such prior art forms part of the common general knowledge, nor should it be construed as such.

[0083] As used in this specification and the following claims, any of the terms "comprise", "include", and their derivatives (e.g., "comprises", "comprising", "includes", "including") should be construed to include the features to which the term refers and not to imply the exclusion of the presence of any additional features, unless specifically stated or implied otherwise.

[0084] In some cases, for the sake of brevity and / or to aid understanding of the scope of the present disclosure, a single embodiment may combine multiple features. In such cases, it should be understood that these multiple features may be provided separately (in separate embodiments) or in any other suitable combination. Alternatively, if distinct features are described in separate embodiments, these distinct features may be combined in a single embodiment unless specifically stated or implied otherwise. This also applies to the claims which may be reconfigured in any combination. That is, the claims may be amended to include features defined in any other claim. Further, the phrase "at least one" in reference to a list of items refers to any combination of those items including a single item. By way of example, "at least one of a, b, or c" is intended to include a, b, c, a - b, a - c, b - c, and a - b - c.

[0085] Those skilled in the art will understand that the present disclosure is not limited in its use to the specific one or more uses described. The present disclosure is not limited in its preferred embodiments with respect to the specific elements and / or features described or depicted herein. The present disclosure is not limited to the one or more disclosed embodiments and it will be understood that numerous rearrangements, modifications, and substitutions are possible without departing from the scope described and defined by the following claims.

Claims

1. A coated article comprising a low-E coating supported by a substrate, wherein the low-E coating comprises a metallic IR reflective layer, a protective layer in contact with the metallic IR reflective layer, and a dielectric layer.

2. The coated article according to claim 1, having a visible transmittance of more than approximately 60% and / or a visible reflectance of more than approximately 60%.

3. The coated article according to claim 1, wherein the low-E coating supported by the substrate has a total thickness in the range of about 90 nm to about 120 nm.

4. The aforementioned metal IR reflective layer is made of Ag, Al, Cu, Zn, Nb, TiN, Ag / Au alloy, Ag / Cu alloy, Ag / Al alloy, NbN ｘ , NbCr, NbCrN ｘ NbZrO ｘ The coated article according to claim 1, comprising and / or Au.

5. The coated article according to any one of claims 1 to 4, wherein the low-E coating comprises one metallic IR reflective layer.

6. The coated article according to any one of claims 1 to 4, wherein the metal IR reflective layer has a thickness of about 5 nm to about 25 nm, preferably about 10 nm to about 20 nm.

7. The protective layer contacting the metal IR reflective layer is nickel-chromium alloy (NiCr), NiCrO ｘ , NiCrN ｘ , NiCrO ｘ N ｙ , Ni ｘ Ti ｙ O ｚ , Ni, Cr, CrN ｘ , NiO ｘ , Ti, TiO ｘ , NbO ｘ , ZnO, Al ２ O ３ and ZnAlO ｘ The coated article according to any one of claims 1 to 4, comprising one or more selected from the group consisting of.

8. The coated article according to any one of claims 1 to 4, wherein the protective layer has a thickness of about 1 nm to about 5 nm, preferably about 2 nm to about 3 nm.

9. The coated article according to any one of claims 1 to 4, wherein the low-E coating comprises one or more dielectric layers.

10. The coated article according to claim 9, wherein each of the dielectric layers has a thickness of about 10 nm to about 45 nm, for example, about 25 nm to about 45 nm.

11. The dielectric layer is TiO ２ Ta ２ O ５ Nb ２ O ５ , ZrO ２ , ZnO, ZnS, ZnSe, HfO ２ LaTiO ３ Al ２ O ３ La ２ O ３ , Y ２ O ３ , Gd ２ O ３ , Sc ２ O ３ Si ３ N ４ SiO ２ LiF, MgF ２ Na ３ AlF ６ , SnO ２ Indium tin oxide (ITO), Al-doped SiO ２ Al-doped zinc oxide (AZO), WO ３ , SiO ｘ N ｙ and SiO ｘ N ｙ A coated article according to any one of claims 1 to 4, comprising one or more selected from the group consisting of the following.

12. A coated article according to any one of claims 1 to 4, wherein a metallic IR reflective layer is sandwiched between two adjacent protective layers, each of which contains NiCr and has a thickness of less than about 5 nm, and the metallic IR reflective layer contains Ag and has a thickness of about 20 nm.

13. The coated article includes a low-E coating supported by a substrate, and the low-E coating is sequentially made outward from the substrate by TiO ２ A dielectric layer containing NiCr, a protective layer containing Ag, a metallic IR reflective layer containing NiCr, and TiO ２ A coated article according to any one of claims 1 to 4, comprising a dielectric layer containing the above.

14. The coated article includes a low-E coating supported by a substrate, wherein the low-E coating has a TiO2 of approximately 25 nm to approximately 45 nm in size, extending outward from the substrate. ２ A dielectric layer, a NiCr protective layer less than approximately 5 nm, an Ag metallic IR reflective layer of approximately 10 nm to approximately 20 nm, a NiCr protective layer less than approximately 5 nm, and a TiO layer of approximately 25 nm to approximately 45 nm. ２ A coated article according to claim 13, comprising a dielectric layer.

15. The coated article includes a low-E coating supported by a substrate, wherein the low-E coating has approximately 40 nm of TiO2 in order from the substrate outward. ２ A dielectric layer, a NiCr protective layer of less than approximately 5 nm, a metallic IR reflective layer of Ag of about 20 nm, a NiCr protective layer of less than approximately 5 nm, and a TiO layer of about 40 nm. ２ A coated article according to claim 14, comprising a dielectric layer.

16. The coated article includes a low-E coating directly supported by a substrate, wherein the low-E coating has approximately 40 nm of TiO2 in order from the substrate outward. ２ A dielectric layer, a protective layer of NiCr(80 / 20) less than approximately 5 nm, a metallic IR reflective layer of Ag approximately 20 nm, a protective layer of NiCr(80 / 20) less than approximately 5 nm, and a TiO layer approximately 40 nm thick. ２ A dielectric layer and approximately 10 nm of SiO ２ or Al-doped SiO ２ The coated article according to claim 15, comprising a dielectric layer / adhesive layer.

17. The coated article according to any one of claims 1 to 4, wherein the outermost layer is a hard coat.

18. The coated article according to any one of claims 1 to 4, wherein the metal IR reflective layer includes a frequency-selective surface configured to reduce attenuation of telecommunications frequency signal transmission.

19. The coated article according to any one of claims 1 to 4, wherein the substrate of the coated article is substantially made of plastic or glass.

20. A method for preparing a coated article according to claim 1, comprising introducing the dielectric layer, the protective layer in contact with the metallic IR reflective layer, and the metallic IR reflective layer onto the substrate.

21. The method according to claim 20, wherein the dielectric layer, the protective layer in contact with the metal IR reflective layer, and the metal IR reflective layer are introduced onto the substrate by magnetron sputtering deposition.

22. Use in automobiles and buildings of a coated article as described in claim 1 or prepared according to claim 20.

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