Material comprising a solar control coating

Abstract

The invention relates to a material comprising a substrate coated with a solar control coating, comprising a single silver-based metal functional layer arranged between two dielectric coatings, each dielectric coating comprising at least one series of three dielectric layers, referred to as a layer of higher refractive index, a layer of lower refractive index, and a layer of higher refractive index, each having a thickness of greater than 5 nm, where the variation in the refractive index between two consecutive layers is greater than 0.25. The layer of lower refractive index has the lowest refractive index and is located between the two layers of higher refractive index.

Description

[0001] Title: Material comprising a solar control coating

[0002] The present invention relates to the field of glazing, and relates more particularly to laminated glazing intended for aeronautics, in particular cockpit glazing.

[0003] Cockpit glazing is a complex system that fulfills multiple roles. It provides physical, acoustic, and thermal protection from the external environment.

[0004] For this purpose, these glazings are laminated glazings. Laminated glazing comprises two or more glass substrates bonded together by polymer interlayers, also called lamination interlayers. Glazings for aeronautics preferably comprise two or three substrates.

[0005] Conventionally, the faces of a glazing unit are designated from the outside by numbering the faces of the substrates from the outside to the inside of the passenger compartment or room it equips. This means that incident sunlight passes through the faces in ascending order of their number.

[0006] In the case of laminated glazing, all the faces of the substrates are numbered but the faces of the lamination interlayers are not numbered. Face 1 is on the outside of the building or vehicle and therefore constitutes the outer wall of the glazing. Faces 2 and 3 are in contact with the lamination interlayer.

[0007] In the case of laminated glazing comprising two substrates, face 4 is inside the building or vehicle and therefore constitutes the inner wall of the glazing.

[0008] In the case of laminated glazing comprising three substrates, faces 4 and 5 are in contact with the second lamination interlayer and face 6 is inside the building or vehicle and therefore constitutes the inner wall of the glazing.

[0009] Laminated glazing for aeronautics preferably has a structure of the first substrate / first polymer interlayer / second substrate / second polymer interlayer / third substrate type.

[0010] These laminated glazings may further comprise coatings providing additional functionalities. For example, at least one of the substrates may be coated with a heating coating with a defrosting function comprising an electrically conductive layer. These electrically conductive layers may be based on an oxide such as indium tin oxide (ITO).

[0011] Due to the intended application, these glazings must necessarily have high light transmission and low absorption. However, while these "substrates", "interlayers" and "functional coatings" constituting the glazings can allow the visible part of the solar spectrum to pass into the cockpit, they also allow most of the infrared radiation to pass through. This results in excessive heating of the cockpit and an increase in its temperature, which must be compensated for by an energy-intensive air conditioning system.

[0012] To overcome this problem, it is possible to introduce, into these cockpit windows, an element with a solar control (or protection) function.

[0013] The "solar control" function or property corresponds to the ability of a glazing to let in visible light while blocking infrared radiation. The selectivity "s", the solar factor (FS or g) and the energy transmission (Te) make it possible to evaluate this property. Selectivity corresponds to the ratio of the light transmission TL VjS in the visible of the glazing on the solar factor FS of the glazing (s = TL vis / FS). The solar factor "FS or g" corresponds to the ratio in % between the total energy entering the room through the glazing and the incident solar energy. The solar factor therefore measures the contribution of a glazing to heating the "room". The smaller the solar factor, the lower the solar gain. Energy transmission corresponds to the percentage of the solar energy flow transmitted directly through the glazed wall.

[0014] The solar control function therefore corresponds to a strong reduction in the energy transmission (TE) and the solar factor (g) of the glazing associated with a slight reduction in the light transmission (TL).

[0015] The purpose of adding a solar control element is to prevent excessive overheating. However, the addition of this element should not be at the expense of light transmission and absorption.

[0016] To this end, the applicant has developed a solar control coating particularly suitable for use in laminated cockpit glazing. The solar control coating makes it possible in particular to obtain the best compromise between low absorption and light transmission and high selectivity. The coating of the invention makes it possible in particular to obtain selectivity values ​​which cannot usually be obtained with a single-layer silver coating. Indeed, selectivities greater than 1.5, or even greater than 1.6, can be obtained. The selectivity is high compared to the absorption tolerance.

[0017] This coating was designed to be integrated into a laminated cockpit glazing structure. However, the coating of the invention is suitable for any application where high light transmission and high selectivity are required, particularly with a functional coating with a single layer of silver.

[0018] The invention therefore relates to a material comprising a substrate coated with a solar control coating comprising a single silver-based functional metal layer disposed between two dielectric coatings, each dielectric coating comprising at least one succession of three dielectric layers referred to as a higher refractive index layer, a lower refractive index layer and a higher refractive index layer, each having a thickness greater than 5 nm, the variation in refractive index between two successive layers being greater than 0.25, greater than 0.30, greater than 0.40, greater than 0.50, greater than 0.60, greater than 0.70 or greater than 0.80, the lower refractive index layer having the lowest refractive index and being located between the two higher refractive index layers.

[0019] The solar control coating of the invention is a coating based on a single layer of silver optimized to exhibit high selectivity, particularly when used in glazing in contact with two media with similar indices (substrate and lamination interlayer). It provides high light transmission and selectivity as well as low absorption.

[0020] The solar control coating comprises a single functional metal layer. In the remainder of the description, the term "functional" qualifying "functional layer" means "capable of acting on solar radiation and / or infrared radiation". This means that the solar control coating does not comprise other layers whose main function is to reflect infrared radiation. Concretely, the solar control coating does not comprise other metal layers than the silver-based functional metal layer having a significant thickness, i.e. other metal layers of at least 5 nm, preferably at least 4 nm, or even at least 2 nm.

[0021] The solar control coating does not comprise a metal layer with a thickness greater than 5 nm other than the single silver-based functional metal layer. Preferably, the solar control coating does not comprise a metal layer with a thickness greater than 8 nm, or even greater than 10 nm, other than the single silver-based functional metal layer.

[0022] The applicant has discovered that it is very difficult to achieve sufficiently low absorption with solar control coatings with several silver-based functional layers. For example, the absorption on clear glass of a solar control coating with two silver-based functional layers is generally greater than 12%. This is due in particular to the presence of at least four "metal / dielectric" interfaces, each of which necessarily generates absorption.

[0023] The invention is therefore deliberately limited to coatings comprising a single silver-based functional layer because they are likely to exhibit visible light absorption values ​​of less than 10% when deposited on clear glass.

[0024] In the specific application targeted by the invention, the solar control coatings are intended to be used on one side of a substrate in contact with a lamination interlayer. These lamination interlayers have a refractive index in the visible substantially equal to that of the mineral or organic substrates on which the solar control coating is deposited. The solar control coating is therefore intended to be used directly in contact with two media with substantially equal refractive indices. This influences these characteristics. The solar control coating may in particular have a symmetry with respect to the silver layer, in terms of the nature of the dielectric layers constituting the dielectric coatings.

[0025] The solar control coating of the invention is optimized to be more selective than known single-layer silver-based coatings of equivalent light transmission. To this end, it comprises, on each side of the silver layer, sequences "layer of higher refractive index / / layer of lower refractive index / / layer of higher refractive index". The symbol " / / " means that the two layers that it separates are not necessarily in contact with each other. The layer of lower refractive index has the lowest refractive index and is located between the two layers of higher refractive index. The presence of these sequences of at least three dielectric layers makes it possible to obtain, for the same level of light transmission, better filtering of infrared rays. This type of sequence of layers makes it possible to lower the solar factor while maintaining high light transmission and therefore to increase selectivity.

[0026] According to the invention, the variation in refractive index between two successive layers of the succession of three dielectric layers is greater than 0.25, greater than 0.30, greater than 0.40, greater than 0.50, greater than 0.60, greater than 0.70 or greater than 0.80.

[0027] Improved selectivity results from precise control of optical interference effects between the different layers making up the coating. This control is achieved by choosing the nature, thickness and sequences of dielectric layers making up the dielectric coatings.

[0028] The thickness limit set for each layer, at least 5 nm, preferably at least 8 nm, or even at least 10 nm, coupled with a sufficient variation in index between two successive layers, are characteristics necessary to obtain an effect by optical interference. Layers of less than 5 nm are not sufficiently thick to have a significant influence by interference effect on light transmission.

[0029] Surprisingly, the best results in terms of low absorption, high light transmission and high selectivity are obtained with a solar control coating having the following characteristic(s):

[0030] - the solar control coating further comprises one or more blocking layers located, in contact, below and / or above the functional metal layer, and / or

[0031] - the dielectric coating located below the functional metal layer further comprises a zinc oxide-based layer located directly in contact with it or separated by a blocking layer, and / or - the dielectric coating located above the functional metal layer further comprises a zinc oxide-based layer located directly in contact with it or separated by a blocking layer, and / or

[0032] - the lower refractive index layer of each dielectric coating has a refractive index less than 1.7, and / or

[0033] - the lower refractive index layer is a silicon oxide-based layer, and / or

[0034] - the lower refractive index layer has an optical thickness greater than 75 nm, greater than 90 nm, greater than 100 nm, greater than 120 nm, greater than 130 nm, greater than 150 nm,

[0035] - the lower refractive index layer has a thickness greater than 50 nm, greater than 60 nm, greater than 70 nm, greater than 80 nm, greater than 90 nm or greater than 100 nm, and / or

[0036] - the lower refractive index layer has a thickness of less than 200 nm, less than 180 nm, less than 170 nm or less than 180 nm, and / or

[0037] - in a dielectric coating, the lower refractive index layer has a geometric thickness which is at least 2 times greater, at least 3 times greater, less than 4 times greater or at least 5 times greater than each of the other two higher refractive index layers, and / or

[0038] - the layer with a lower refractive index has an optical thickness which is at least 2 times greater, at least 3 times greater, less than 4 times greater, than each of the two other layers with a higher refractive index,

[0039] - the dielectric layers with a higher refractive index of each dielectric coating are chosen from layers based on silicon nitride, based on zinc and tin oxide, based on zinc oxide or based on titanium oxide, and / or

[0040] - the three layers of the succession of layers are in contact with each other, that is to say that the first upper refraction layer is in contact with the lower refraction layer and the lower refraction layer is in contact with the second upper refraction layer, and / or

[0041] - each dielectric coating comprises, starting from the functional metal layer, the same succession of three dielectric layers described as a higher refractive index layer, a lower refractive index layer and a higher refractive index layer, and / or

[0042] - each dielectric coating comprises oxide layers and the sum of the thicknesses of all the oxide layers present in each dielectric coating represents at least 50%, 60% or 70% of the total thickness of the dielectric coating considered, and / or

[0043] - each dielectric coating comprises layers comprising silicon and the sum of the thicknesses of all the layers comprising silicon present in each dielectric coating represents at least 50%, 60% or 70% of the total thickness of the dielectric coating considered, and / or

[0044] - the succession of at least three layers includes:

[0045] - a layer based on silicon nitride,

[0046] - a layer based on silicon oxide,

[0047] - a layer based on silicon nitride, or

[0048] - a layer based on titanium oxide,

[0049] - a layer based on silicon oxide,

[0050] - a layer based on titanium oxide,

[0051] - each dielectric coating comprises the same sequence of at least four layers, sequence defined from the silver-based functional metal layer, preferably the same sequence of at least four layers comprises:

[0052] - a layer based on zinc oxide,

[0053] - a layer based on silicon nitride,

[0054] - a layer based on silicon oxide,

[0055] - a layer based on silicon nitride, or

[0056] - a layer based on zinc oxide,

[0057] - a layer based on titanium oxide,

[0058] - a layer based on silicon oxide,

[0059] - a layer based on titanium oxide, and / or

[0060] - the substrate is chemically toughened glass, and / or - the substrate is curved glass.

[0061] The invention also relates to a laminated glazing comprising a material according to the invention and at least one second substrate, the material and the second substrate are bonded together via a first lamination interlayer. The solar control coating is preferably positioned on face 2 or 3. The first lamination interlayer is preferably made of polyurethane.

[0062] The laminated glazing may comprise a third substrate bonded to the second substrate or material via a second polymeric interlayer.

[0063] The laminated glazing may further comprise a heating coating comprising an electrically conductive layer, located on one face of a substrate not comprising the solar control coating, preferably on face 2 or face 3.

[0064] The materials and glazings according to the invention have a selectivity greater than 1.45 or greater than 1.5.

[0065] Preferably, all substrates are made of curved and chemically toughened glass. The invention also relates to:

[0066] - laminated glazing according to the invention mounted on a vehicle or on a building, and

[0067] - the process for preparing laminated glazing according to the invention,

[0068] - the use of laminated glazing according to the invention as solar control glazing for buildings or vehicles,

[0069] - a building, a vehicle comprising glazing according to the invention.

[0070] The preferred characteristics which appear in the remainder of the description are applicable both to the material according to the invention and, where appropriate, to the glazing, the process, the use, the building or the vehicle according to the invention.

[0071] All the luminous characteristics described are obtained according to the principles and methods of the ISO 9050 standard relating to the determination of the luminous and solar characteristics of glazing used in glass for construction.

[0072] Conventionally, refractive indices are measured at a wavelength of 550 nm.

[0073] According to the invention, two elements such as layers or substrates have substantially equal refractive indices, when the absolute value of the difference between the refractive indices of the two materials constituting said layers or substrates at 550 nm is less than or equal to 0.15.

[0074] The layers of higher refractive index and the layers of lower refractive index have different refractive indices. According to the invention, two elements such as layers or substrates have different refractive indices, when the absolute value of the difference between the refractive indices of the two materials constituting said layers or substrates at 550 nm is greater than or equal to 0.25, greater than 0.30, greater than 0.40, greater than 0.50, greater than 0.60, greater than 0.70 or greater than 0.80.

[0075] Unless otherwise stated, the thicknesses mentioned in this document without further details are physical, real or geometric thicknesses called Ep and are expressed in nanometers (and not optical thicknesses). The optical thickness Eo is defined as the physical thickness of the layer considered multiplied by its refractive index at the wavelength of 550 nm: Eo = n*Ep. Since the refractive index is a dimensionless value, the unit of optical thickness can be considered to be that chosen for the physical thickness.

[0076] The solar control coating is deposited by magnetic field-assisted sputtering (magnetron process). In this advantageous embodiment, all layers of the coatings are deposited by magnetic field-assisted sputtering.

[0077] In the absence of a specific stipulation, the expressions "above" and "below" do not necessarily mean that two layers and / or coatings are placed in contact with each other. When it is specified that a layer is deposited "in contact" with another layer or coating, this means that there cannot be one (or more) layer(s) interposed between these two layers (or layer and coating).

[0078] In this description, unless otherwise indicated, the expression "based on", used to qualify a material or a layer as to what it contains, means that the mass fraction of the constituent that it comprises is at least 50%, in particular at least 70%, preferably at least 90%.

[0079] According to the invention:

[0080] - light reflection corresponds to the reflection of solar radiation in the visible part of the spectrum,

[0081] - light transmission corresponds to the transmission of solar radiation in the visible part of the spectrum,

[0082] - light absorption corresponds to the absorption of solar radiation in the visible part of the spectrum.

[0083] Ordinary clear glass 4-6 mm thick has the following light characteristics:

[0084] - a light transmission between 87 and 91.5%,

[0085] - a light reflection of between 7 and 9.5%,

[0086] - a light absorption of between 0.3 and 5%.

[0087] The solar control coating consists of a single silver-based functional metal layer.

[0088] The silver-based metal functional layers comprise at least 95.0%, preferably at least 96.5% and more preferably at least 98.0% by mass of silver relative to the mass of the functional metal layer. Preferably, a silver-based metal functional layer comprises less than 1.0% by mass of metals other than silver relative to the mass of the silver-based metal functional layer.

[0089] The silver-based metal functional layers have a thickness:

[0090] - greater than 5 nm, 6 nm, 7 nm, 8 nm or 9 nm, and / or

[0091] - less than 25 nm, 22 nm, 20 nm, 18 nm, 16 nm, 15 nm, 14 nm or 13 nm.

[0092] The solar control coating may further comprise one or more blocking layers located, in contact, below and / or above the functional metal layer.

[0093] Blocking layers traditionally serve to protect the functional layers from possible degradation during the deposition of the upper anti-reflective coating and during possible high-temperature heat treatment, such as annealing, bending and / or quenching. Blocking layers are chosen from:

[0094] - metallic layers based on a metal or a metallic alloy, metallic nitride layers, and metallic oxynitride layers of one or more elements chosen from titanium, zinc, tin, nickel, chromium and niobium,

[0095] - metal oxide layers of one or more elements chosen from titanium, nickel, chromium and niobium.

[0096] The blocking layers may in particular be, as deposited, layers of Ti, TiN, TiOx, Nb, NbN, Ni, NiN, Cr, CrN, NiCr, NiCrOx, NiCrN, SnZnN. When these blocking layers are deposited in metallic, nitrided or oxynitrided form, these layers may undergo partial or total oxidation depending on their thickness and the nature of the layers surrounding them, for example, at the time of deposition of the next layer or by oxidation in contact with the underlying layer.

[0097] Preferably, the blocking layers are titanium layers, i.e. these layers have been deposited in the form of metallic titanium.

[0098] According to advantageous embodiments of the invention, the blocking layer(s) satisfy one or more of the following conditions:

[0099] - the functional metal layer is in contact with a blocking overlayer, and / or

[0100] - the blocking layers are layers of titanium deposited in metallic form, and / or

[0101] - the thickness of each blocking layer is at least 0.05 nm, or between 0.08 and 2.00 nm, between 0.10 and 1.00 nm or between 0.05 and 0.50 nm.

[0102] The sum of the thicknesses of all blocking layers may be less than 2.0 nm, less than 1.5 nm, less than 1.0 nm or less than 0.5 nm.

[0103] Dielectric coatings comprise dielectric layers. By "dielectric layer" for the purposes of the present invention, it is understood that from the point of view of its nature, the material is "non-metallic", i.e. is not a metal. In the context of the invention, this term designates a material having an n / k ratio over the entire visible wavelength range (from 380 nm to 780 nm) equal to or greater than 5.

[0104] Preferably, each dielectric coating consists of only one or more dielectric layers. Preferably, there is therefore no absorbing layer in the dielectric coatings so as not to reduce the light transmission.

[0105] The dielectric layers of the coatings have the following characteristics alone or in combination:

[0106] - they are deposited by magnetic field-assisted cathode sputtering,

[0107] - they have a thickness greater than 2 nm, preferably between 4 and 200 nm.

[0108] Dielectric layers, in addition to their optical function, can have various other functions. For example, stabilizing layers, smoothing layers, and barrier layers can be cited. Dielectric layers are conventionally chosen from oxide-based, nitride-based, or oxynitride-based layers. Oxide-based layers of one or more elements comprise essentially oxygen and very little nitrogen. Oxide-based layers notably comprise at least 90% atomic percentage of oxygen relative to the oxygen and nitrogen in said layer. Nitride-based layers comprise essentially nitrogen and very little oxygen. Nitride-based layers comprise at least 90% atomic percentage of nitrogen relative to the oxygen and nitrogen in said layer. Oxynitride-based layers comprise a mixture of oxygen and nitrogen.Silicon oxynitride-based layers comprise 10 to 90% (limits excluded) in atomic percentage of nitrogen relative to oxygen and nitrogen in said layer.

[0109] The amounts of oxygen and nitrogen in a layer are determined as atomic percentages relative to the total amounts of oxygen and nitrogen in the layer under consideration.

[0110] The dielectric layers are classically chosen from:

[0111] - layers comprising silicon, aluminum and / or zirconium, optionally doped with at least one other element,

[0112] - layers based on zinc and tin oxide,

[0113] - layers based on titanium oxide,

[0114] - zinc oxide-based layers.

[0115] The layers comprising silicon comprise at least 50% by mass of silicon relative to the mass of all elements constituting the layer comprising silicon other than nitrogen and oxygen.

[0116] The layers comprising silicon may be selected from oxide-based, nitride-based or oxynitride-based layers such as silicon oxide-based layers, silicon nitride-based layers and silicon oxynitride-based layers.

[0117] The silicon oxide-based layers comprise at least 90 atomic percent oxygen relative to the oxygen and nitrogen in the silicon oxide-based layer. The silicon nitride-based layers comprise at least 90 atomic percent nitrogen relative to the oxygen and nitrogen in the silicon nitride-based layer. The silicon oxynitride-based layers comprise 10 to 90 atomic percent nitrogen relative to the oxygen and nitrogen in the silicon oxide-based layer. Preferably, the silicon oxide-based layers are characterized by a refractive index at 550 nm of less than or equal to 1.55. Preferably, the silicon nitride-based layers are characterized by a refractive index at 550 nm of greater than or equal to 1.95.

[0118] The layers comprising silicon may comprise or consist of elements other than silicon, oxygen and nitrogen. These elements may be selected from aluminum, boron, titanium, and zirconium. The layers comprising silicon may comprise at least 2%, at least 5% or at least 8% by mass of aluminum relative to the mass of all elements constituting the layer comprising silicon other than oxygen and nitrogen.

[0119] The layers comprising aluminum may be chosen from oxide-based, nitride-based or oxynitride-based layers such as aluminum oxide-based layers such as AI2O3, aluminum nitride-based layers such as AIN and aluminum oxynitride-based layers such as AlOxNy.

[0120] Dielectric layers are divided into low refractive index layers, intermediate refractive index layers, and high refractive index layers, depending on their refractive index at 550 nm. Low refractive index layers have a refractive index of less than 1.70. Intermediate refractive index layers have a refractive index between 1.70 and 2.2. High refractive index layers have a refractive index greater than 2.2.

[0121] The low index layers may have a refractive index less than 1.70, less than 1.6 or less than 1.5. The low index layers are preferably silicon oxide-based layers.

[0122] The intermediate refractive index layers can be chosen from:

[0123] - zinc oxide-based layers (n550 = 2.0),

[0124] - layers based on tin oxide (n550 = 2.0),

[0125] - layers based on zinc and tin oxide (n550 = 2.0),

[0126] - layers based on silicon and / or aluminum nitride (n550 = 2.0),

[0127] - layers based on silicon and / or aluminum oxynitride.

[0128] High refractive index layers can have a refractive index:

[0129] - greater than 2.30, greater than 2.35 or greater than 2.40.

[0130] - less than 2.60, less than 2.50, less than 2.40.

[0131] High refractive index layers can be chosen from:

[0132] - layers based on titanium oxide (n550=2.4),

[0133] - layers based on mixed titanium oxide and another component chosen from the group consisting of Zn, Zr and Sn,

[0134] - layers based on a layer of zirconium nitride (n 550 = 2.55),

[0135] - layers based on silicon and zirconium nitride (n550 nm = 2.20 - 2.40),

[0136] - layers based on a layer of zirconium oxide,

[0137] - layers based on manganese oxide MnO (n550 = 2.16),

[0138] - layers based on a layer of tungsten oxide (n550 = 2.15),

[0139] - layers based on a layer of niobium oxide (n550 = 2.30),

[0140] - layers based on a layer of bismuth oxide (n 550 = 2.60). The layer with a lower refractive index can be chosen from among the layers with a low refractive index. In this case, the layers with a higher refractive index are chosen from among the layers with a refractive index greater than 1.7. They are therefore chosen from among the layers with intermediate refraction and the layers with a high refractive index.

[0141] The lower refractive index layer can be selected from the intermediate refractive index layers. In this case, the higher refractive index layers are selected from the high refractive index layers.

[0142] The dielectric coatings may comprise so-called stabilizing layers which reinforce the adhesion of the functional metal layer to the layers which surround it, and in fact oppose the migration of its constituent material. The stabilizing layers are preferably layers based on zinc oxide optionally doped, for example, with aluminum. The zinc oxide is crystallized. The zinc oxide-based layer comprises, in increasing order of preference, at least 90.0%, at least 92%, at least 95%, at least 98.0% by mass of zinc relative to the mass of elements other than oxygen in the zinc oxide-based layer.

[0143] According to this embodiment, the dielectric coating located below the functional metal layer may further comprise a zinc oxide-based layer located directly in contact with it or separated by a blocking layer. Indeed, it is advantageous to have a stabilizing layer below a functional metal layer, because it facilitates the adhesion and crystallization of the silver-based functional metal layer and increases its quality and stability.

[0144] According to this embodiment, the dielectric coating located above the functional metal layer further comprises a zinc oxide-based layer located directly in contact with it or separated by a blocking layer. It is also advantageous to have a stabilizing layer, above a functional metal layer, to increase its adhesion and optimally oppose diffusion on the side of the stack opposite the substrate.

[0145] In these embodiments, the zinc oxide-based layers are distinct from the three dielectric layers referred to as the higher refractive index layer, the lower refractive index layer, and the higher refractive index layer.

[0146] The zinc oxide layers have, in order of increasing preference, a thickness:

[0147] - at least 3.0 nm, at least 4.0 nm, at least 5.0 nm, and / or

[0148] - not more than 15 nm, not more than 10 nm, not more than 8.0 nm.

[0149] The sum of the physical thicknesses of all layers comprising silicon in each dielectric coating is greater than 50%, 60% or 70% of the total thickness of the dielectric coating under consideration. The sum of the physical thicknesses of all oxide layers in each dielectric coating is greater than 50%, 60% or 70% of the total thickness of the dielectric coating under consideration.

[0150] The solar control coating is preferably symmetrical with respect to the agent layer. This means that there are sequences of layers of identical nature on each side of the silver layer. The following characteristics, alone or in combination, define this symmetry:

[0151] - the dielectric layers of higher refractive index of the same dielectric coating may be of the same nature, and / or

[0152] - the dielectric layers of lower refractive index of each dielectric coating may be of the same nature, and / or

[0153] - the dielectric layers of higher refractive index closest to the functional metal layer of each dielectric coating may be of the same nature, and / or

[0154] - the dielectric layers of higher refractive index furthest from the functional metal layer of each dielectric coating may be of the same nature, and / or

[0155] - the ratio of the optical or geometric thicknesses of the dielectric coatings is between 0.8 and 1.2, or 0.9 and 1.1, and / or

[0156] - each dielectric coating comprises, starting from the functional metal layer, the same succession of three dielectric layers described as a higher refractive index layer, a lower refractive index layer and a higher refractive index layer, and / or

[0157] - the succession of three layers includes:

[0158] - a layer based on silicon nitride,

[0159] - a layer based on silicon oxide,

[0160] - a layer based on silicon nitride, or

[0161] - a layer based on titanium oxide,

[0162] - a layer based on silicon oxide,

[0163] - a layer based on titanium oxide,

[0164] - each dielectric coating comprises the same sequence of at least four layers, sequence defined from the silver-based functional metal layer, and / or

[0165] - the same sequence of at least four layers includes:

[0166] - a layer based on zinc oxide,

[0167] - a layer based on silicon nitride,

[0168] - a layer based on silicon oxide, - a layer based on silicon nitride, or

[0169] - a layer based on zinc oxide,

[0170] - a layer based on titanium oxide,

[0171] - a layer based on silicon oxide,

[0172] - a layer based on titanium oxide.

[0173] Examples of a three-layer succession according to the invention include:

[0174] - titanium oxide-based layer / / silicon oxide-based layer / / titanium oxide TiO2-based layer,

[0175] - silicon nitride-based layer / / silicon oxide-based layer / / silicon nitride-based layer,

[0176] - silicon nitride-based layer / / silicon oxide-based layer / / titanium oxide TiO2-based layer,

[0177] - titanium oxide-based layers / / silicon oxide-based layer / / silicon nitride-based layer,

[0178] - layer based on silicon nitride and zirconium / / layer based on silicon oxide / / layer based on silicon nitride and zirconium,

[0179] - layer based on silicon nitride and zirconium / / layer based on silicon nitride / / layer based on silicon nitride and zirconium.

[0180] The invention also relates to a laminated glazing preferably comprising at least three substrates. This particular structure based on at least three substrates linked together by two polymer interlayers is particularly suitable for aeronautical applications.

[0181] According to an advantageous embodiment, the laminated glazing comprises:

[0182] - a first chemically hardened and possibly curved substrate,

[0183] - a first lamination interlayer,

[0184] - a second chemically hardened and possibly curved substrate,

[0185] - a second lamination interlayer,

[0186] - a third chemically hardened and possibly curved substrate.

[0187] The laminated glazing may further comprise a heating coating comprising an electrically conductive layer located on one face of a substrate not comprising the solar control coating, preferably on face 2 or face 3.

[0188] The laminated glazing of the invention may therefore further comprise:

[0189] - a heating coating,

[0190] - a solar control coating comprising at least one silver-based layer, the heating coating and the solar control coating are preferably each in contact with the first lamination interlayer, on one face of the first substrate and on one face of the second substrate.

[0191] The heating coatings suitable according to the invention are described in particular in application WO 2020 / 120879. The heating coating comprises at least one electrically conductive layer which is a transparent conductive oxide layer.

[0192] Heating is achieved by the Joule effect. The heating layer is powered by energized electrodes. Uniform heating of a non-rectangular shape is impossible with a layer of uniform electrical conductivity.

[0193] To homogenize heating on a complex surface such as a windshield, the electrically conductive layer can have an electrical conductivity gradient. This gradient can be achieved by a thickness gradient. Large variations in layer thickness can limit the current density in certain parts of the heating surface.

[0194] To homogenize the heating, the electrically conductive layer may also include ablation lines, called flux separation lines or more commonly flux lines as described in patent EP1897412-B1, which guide the flow of electric current.

[0195] These two strategies can be used in combination.

[0196] The electrically conductive layer has one or more of the following characteristics:

[0197] - it is located on an inward-facing face of the first substrate or on an inward-facing or outward-facing face of the second substrate, and / or

[0198] - it comprises a conductive oxide layer based on doped metal oxide such as tin-doped indium oxide (ITO “Indium Tin Oxide”), aluminum-doped zinc oxide (AZO, “Aluminum Zinc Oxide”), fluorine-doped tin oxide (SnO2:F), and / or

[0199] - it has a thickness of 2 to 1600 nm, preferably 30 to 300 nm or 50 to 250 nm, and / or

[0200] - it has a thickness greater than 50 nm, greater than 100 nm, greater than 150 nm, this means that it has this thickness on at least part of the surface of the substrate and / or

[0201] - it has a thickness gradient, i.e. a variation in its thickness, this is reflected for example by the existence of at least two zones of different thickness and a ratio between the thickness of these two zones greater than 2, 3, 4 or 6, and / or

[0202] - it has flux lines to guide the electric current preferably having a width between 5 and 1000 pm.

[0203] The thickness ratio between these two zones of different thicknesses therefore corresponds to the ratio of the thickness of the thicker layer to the thickness of the thinner layer.

[0204] When the substrate is made of chemically toughened glass, the functional coating and the heating coating are necessarily deposited after the chemical strengthening step. These coatings do not undergo any heat treatment step after deposition other than the lamination step. They must therefore preferably have acquired their final properties directly after deposition.

[0205] The substrates can be mineral glass or transparent polymer material substrates.

[0206] The mineral glass substrates that make up the glazing can be soda-lime, aluminosilicate or borosilicate glass.

[0207] Preferably, the mineral glass substrate is:

[0208] - chemically tempered glass and / or

[0209] - a curved glass.

[0210] Chemically toughened glass substrates include a compressive surface zone obtained by ion exchange. This compressive surface zone is obtained by the surface substitution of an ion of the glass substrate (usually an alkali ion such as sodium or lithium) by an ion of larger ionic radius (usually an alkali ion, such as potassium or sodium). This allows compressive stresses to be created on the surface of the glass substrate, up to a certain depth. These compressive surface stresses are in fact balanced by the presence of a central tension zone. There is therefore a certain depth at which the transition between compression and tension occurs, a depth called the surface exchange depth.

[0211] These chemically toughened glass substrates can be defined as follows:

[0212] - they include a surface area in compression obtained by ion exchange, and / or

[0213] - they have a surface exchange depth greater than 50 pm and / or

[0214] - they have surface compression stresses greater than 100 MPa.

[0215] Chemical hardening processes are well known. Reference may be made in particular to patent application WO1994008910.

[0216] The substrates can be made of transparent polymeric material which include poly(methyl methacrylate) (PMMA), polycarbonate (PC), polyurethane or polyurea (PU) substrates.

[0217] The solar control coating and the heating coating are necessarily deposited after the chemical reinforcement step. These coatings do not normally undergo a heat treatment step after deposition. They should therefore preferably have acquired their final properties directly after deposition.

[0218] Preferably, the lamination interlayers comprise one or more sheets of organic polymers.The organic polymers are selected from polyvinyl butyral (PVB), polyurethanes (PU), polyureas, ethylene vinyl acetate (EVA), polyolefins (including polyethylene (PE), polypropylene (PP) or polyisobutylene (P-IB)), polyvinyl chloride and its derivatives (e.g. poly(vinyl dichloride) (PVDC)), styrenic polymers (e.g. polystyrene (PS), acrylostyrene butadiene (ABS), styrene acrylonitrile (SAN)), polyacrylics (including polyacrylonitrile (PAN) and poly(methyl methacrylate) (PMMA)), polyesters (including poly(ethylene terephthalate) (PET) and poly(butylene terephthalate) (PBT)), polyoxymethylene (POM), polyamides (PA), fluorinated polymers such as polychlorotrifluoroethylene (PCTFE), polycarbonates (PC), aromatic polysulfones including polysulfone (PSll), polyphenylene ethers (PPE), epoxies (EP) alone or as a mixture and / or copolymer of several of them.

[0219] The particular structure based on at least three substrates bonded together by two polymer interlayers is particularly suitable for aeronautical applications. In the case of an air vehicle, the first substrate is not held by a vehicle bonding system. Only the other two substrates, called structural, are held.

[0220] The first substrate constitutes the outer part of the glazing. It is not structurally fixed to the vehicle or building it is fitted to. It is simply held to the second substrate by the polymer interlayer.

[0221] The second and third substrates are mechanically fixed in the building or vehicle. These two substrates provide protection for people inside the vehicle. The assembly formed by the second substrate, the second polymer interlayer and the third substrate must therefore have excellent impact resistance.

[0222] As a result, the edge of the first substrate may be set back relative to that of the second substrate to prevent delamination phenomena due to deformations of the glazing subjected to the pressure of the aircraft or to the mechanisms of tearing and / or peripheral shearing of the external substrate.

[0223] The first polymer interlayer is preferably polyurethane-based. The specific choice of this material for this polymer interlayer is justified because it is less hygroscopic, i.e. it has less tendency to absorb and / or retain water than other polymer interlayers, for example PVB. This first interlayer keeps the substrate furthest outward and therefore most likely to be subjected to extreme climatic conditions. The second polymer interlayer is preferably polyvinylbutadiene-based. The specific choice of this material for this polymer interlayer is justified because it has better mechanical properties, particularly impact resistance. In addition, due to its "inner" position, its chemical durability is less critical than that of the first polymer interlayer.

[0224] Figure 1 schematically represents a cross-sectional view of an embodiment of the laminated glazing of the invention for a cockpit. A laminated glazing according to the invention therefore comprises:

[0225] - a first glass substrate S1 constituting an outer face of the curved and chemically toughened glazing, for example 3 mm thick,

[0226] - a first interlayer 11 of polyurethane (PU), for example 5 mm thick, - a second substrate of curved and chemically toughened S2 glass, for example 6 mm thick,

[0227] - a second interlayer 12 of polyvinyl butyral (PVB) 1.1 mm thick,

[0228] - a third S3 substrate of curved and chemically toughened glass, for example 6 mm thick,

[0229] - possibly two R1 and R2 coatings including a heating coating and a solar control coating.

[0230] Preferably, the entire peripheral edge of the laminated glazing is covered by a seal (J). This includes the edge of the first glass substrate, the edge of the first interlayer, a portion of the surface of the second glass substrate extending beyond the first glass substrate, the edge of the second glass substrate, the edge of the second interlayer and the edge of the third glass substrate.

[0231] Another object of the invention consists of the use of the laminated glazing described above as glazing for buildings, land, air or water vehicles, in particular as glazing for the cockpit of an air vehicle.

[0232] Finally, the invention relates to the method for preparing laminated glazing comprising the following steps:

[0233] - a step of bending two or three chemically hardened substrates, then

[0234] - a step of depositing by cathodic sputtering a solar control coating on one of the faces of a substrate to obtain a material according to the invention and optionally a step of depositing a heating coating on one of the faces of a substrate not comprising the solar control coating,

[0235] - a lamination step by heating the two or three substrates.

[0236] Examples

[0237] I. Materials and coatings

[0238] 1. General information

[0239] In these examples, the glass substrates are chemically toughened and curved aluminosilicate glass substrates.

[0240] The lamination interlayers are chosen from interlayers:

[0241] - in 6.5 mm polyurethane or

[0242] - in 0.38 mm PVB, - in 1.1 mm PVB.

[0243] Functional coatings are described below.

[0244] 2. Solar control coating

[0245] The functional metal layers (F) are silver (Ag) layers. The blocking layers are titanium (Ti) metal layers. The dielectric coatings include layers selected from:

[0246] - layers based on titanium oxide (TiOx, n = 2.4),

[0247] - layers based on zinc and tin oxide (SnZnO, n = 2.0),

[0248] - layers based on silicon nitride (Si3N4, n = 2.0),

[0249] - layers based on silicon oxide (SiO2, n = 1.5),

[0250] - layers based on zinc oxide (ZnO, n = 2.0).

[0251] The deposition conditions of the layers, which were deposited by sputtering (so-called “magnetron cathode sputtering”), are summarized in Table 1.

[0252] [Table 1]

[0253] Pds: Weight; at: Atomic

[0254] Solar control coatings defined below are deposited on glass substrates.

[0255] Table 2 lists the materials and physical thicknesses in nanometers (unless otherwise indicated) of each layer or coating that constitutes the coatings according to their position relative to the substrate carrying the stack (last line at the bottom of the table).

[0256] [Table 2]

[0257] CB: Blocking layer; CF: Functional metal layer.

[0258] Finally, two comparative solar control coatings comprising more than one layer of silver were also used:

[0259] Cp.5: Substrate / SisN4 31 nm / ZnO 5 nm / Ag 8 nm / Ti 0.1 nm / ZnO 5 nm / SisN4 70 nm / ZnO 5 nm / Ag 8 nm / Ti 0.1 nm / ZnO 5 nm / SisN4 39 nm.

[0260] Cp.6: Substrate / SisN4 33 nm / ZnO 5 nm / Ag1 8 nm / Ti 0.1 nm / ZnO 5 nm / SisN4 73 nm / ZnO 5 nm / Ag 8 nm / Ti 0.1 nm / ZnO 5 nm / SisN4 81 nm / ZnO 5 nm / Ag 8 nm / Ti 0.1 nm / ZnO 5 nm / SisN4 42 nm.

[0261] 2. Heating coating

[0262] The heating coating consists of a 200 nm layer of indium tin oxide. This layer was deposited by magnetron sputtering on a 3 mm glass substrate. It has a sheet resistance of 10 Q / n measured by induction.

[0263] This substrate is used in some examples as a glass substrate coated with a heating coating comprising an ITO-based electrically conductive layer.

[0264] II. Configurations

[0265] 1. Glazing

[0266] The laminated glazing has the following configuration: a first glass substrate 2 mm thick, optionally coated on face 2 with a solar control coating / a first PVB interlayer (0.38 mm) / a second glass substrate 2 mm thick.

[0267] [Table 3] [Table 4]

[0268] The solution of the invention makes it possible to considerably improve the light transmission / selectivity pair. In this range of stacking with very high TL after lamination, the comparative examples not comprising the succession of three layers described as higher refractive index layer, lower refractive index layer and higher refractive index layer have a much lower selectivity than the glazings according to the invention, and this independently of the number of silver layers.

[0269] 2. Glazing optimized for aeronautics

[0270] The laminated glazing has the following configuration: a first 3 mm thick glass substrate coated on face 2 with a heating coating / a first polyurethane (PU) interlayer / a second 6 mm thick glass substrate possibly coated with a solar control coating on face 3 / a second polyvinyl butyral (PVB) interlayer / a third 6 mm thick substrate.

[0271] The reference glazing does not include solar control coating.

[0272] The comparative glazings and those according to the invention comprise a solar control coating on the face 3 of the glazing corresponding to the first face of the second substrate.

[0273] Cp.1 to Cp.4 glazing includes a non-optimized solar control coating according to the invention.

[0274] The glazings according to the invention comprise a solar control coating according to the invention. [Table 6]

[0275] The optical properties and energy performances were determined by simulation on laminated glazing.

[0276] [Table 7]

[0277] [Table 8]

[0278] V.52 and V.62 glazing with 2- and 3-layer silver functional coatings does not provide sufficiently high light transmission. In particular, it has a light absorption of more than 20%.

[0279] The glazings according to the invention and comparative V.12 to V.14 all comprise a functional coating with a single layer of silver. They all have substantially equal light transmission values ​​(between 70 and 72%).

[0280] V.12 to V.42 glazing does not have a high light transmission and selectivity pair. V.22 glazing includes sequences of three low index / high index / low index layers.

[0281] The glazing according to the invention has a high light transmission / selectivity pair thanks to the excellent infrared filtering effect.

[0282] The invention makes it possible, without reducing the light transmission, to improve the selectivity by more than 20% compared to a glazing without solar control coating (comparison of the glazings of the invention and of Ref). The significant improvement in selectivity is also obtained compared to a glazing with a non-optimized solar control coating according to the invention (comparison of the glazings of the invention and of V.12).

[0283] The invention allows a reduction in the solar factor of more than 5 percentage points compared to glazing with solar control coating not optimized according to the invention.

[0284] The glazings according to the invention offer the best compromise between high light transmission and selectivity and low solar factor.

Claims

Demands 1. Material comprising a substrate coated with a solar control coating comprising a single functional metallic layer disposed between two dielectric coatings, the functional metallic layer being silver-based, characterized in that each dielectric coating comprises at least a succession of three dielectric layers referred to as a layer with a higher refractive index, a layer with a lower refractive index and a layer with a higher refractive index, each having a thickness greater than 5 nm, the variation of whose refractive index between two successive layers is greater than 0.25, the layer with a lower refractive index having the lowest refractive index and being located between the two layers with a higher refractive index.

2. Material according to the preceding claim characterized in that the solar control coating further comprises one or more blocking layers located, in contact, below and / or above the functional metallic layer.

3. Material according to any one of the preceding claims characterized in that the dielectric coating located below the functional metallic layer further comprises a zinc oxide-based layer located directly in contact with it or separated by a blocking layer.

4. Material according to any one of the preceding claims characterized in that the dielectric coating located above the functional metallic layer further comprises a zinc oxide-based layer located directly in contact with it or separated by a blocking layer.

5. Material according to any one of the preceding claims characterized in that the lower refractive index layer of each dielectric coating has a refractive index of less than 1.

7.

6. Material according to the preceding claim characterized in that the lower refractive index layer is a silicon oxide-based layer.

7. Material according to any one of the preceding claims characterized in that the lower refractive index layer has an optical thickness greater than 75 nm.

8. Material according to any one of the preceding claims characterized in that, in a dielectric coating, the lower refractive index layer has a geometric thickness that is at least 2 times greater than each of the other two higher refractive index layers.

9. Material according to any one of the preceding claims characterized in that the higher refractive index dielectric layers of each dielectric coating are selected from silicon nitride-based, zinc tin oxide-based, zinc oxide-based or titanium oxide-based layers.

10. Material according to any one of the preceding claims characterized in that each dielectric coating comprises, starting from the functional metallic layer, the same succession of three dielectric layers referred to as the upper refractive index layer, the lower refractive index layer and the upper refractive index layer.

11. Material according to the preceding claim characterized in that the succession of at least three layers comprises: - a silicon nitride-based layer, - a layer based on silicon oxide, - a silicon nitride-based layer, or - a layer based on titanium oxide, - a layer based on silicon oxide, - a layer based on titanium oxide.

12. Material according to any one of the preceding claims characterized in that each dielectric coating comprises the same sequence of at least four layers, sequence defined from the silver-based functional metallic layer.

13. Material according to the preceding claim characterized in that the same sequence of at least four layers comprises: - a zinc oxide-based layer, - a silicon nitride-based layer, - a layer based on silicon oxide, - a silicon nitride-based layer, or - a zinc oxide-based layer, - a layer based on titanium oxide, - a layer based on silicon oxide, - a layer based on titanium oxide.

14. Material according to any one of the preceding claims characterized in that the substrate is chemically tempered glass.

15. Material according to any one of the preceding claims characterized in that the substrate is a curved glass.

16. Laminated glazing comprising a material according to any one of claims 1 to 15 and at least a second substrate, the material and the second substrate are linked together via a first lamination interlayer, face 1 is on the outside of the building or vehicle and therefore constitutes the outer wall of the glazing, faces 2 and 3 are in contact with the lamination interlayer.

17. Laminated glazing according to claim 16 characterized in that the solar control coating is positioned on face 2 or 3.

18. Laminated glazing according to claim 16 or 17 characterized in that it further comprises a heating coating including an electroconductive layer located on one face of a substrate not comprising the solar control coating, preferably on face 2 or face 3.

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