Composite pane having a thermochromic layer and a vacuum layer

Abstract

The invention relates to a composite pane, comprising an outer pane (1) and an inner pane (2), which are connected together face-to-face, wherein the composite pane has a thermochromic layer (3) which is situated between the outer pane (1) and the inner pane (2), and between the thermochromic layer (3) and the inner pane (2) is an evacuated cavity (4).

Description

[0001] SAINT-GOBAIN SEKURIT FRANCE 2024340-WO-PCT

[0002] Composite disc with thermochromic layer and vacuum layer

[0003] The invention relates to a composite disc equipped with a thermochromic layer and an evacuated cavity (a “vacuum layer”).

[0004] Glazing in buildings or vehicles serves to allow occupants a view of the outside environment and to ensure that light enters the interior. However, glazing always presents a challenge for thermal comfort in the interior – in summer, the interior heats up from the outside through the glazing, while in winter, it cools down through the glazing, primarily through heat radiation and conduction. This heat transfer necessitates the use of cooling devices such as air conditioning at high outside temperatures and heating devices at low outside temperatures. This, in turn, increases energy consumption.

[0005] A large portion of heat transfer is caused by thermal radiation. At high outside temperatures (in summer), the interior heats up both through direct solar radiation in the near-infrared range and through thermal radiation from the heated laminated glass in the mid-infrared range. The heat input resulting from these two effects is typically characterized by the so-called TTS value (total solar transmittance). At low outside temperatures (in winter), the interior cools down due to thermal radiation to the outside. In addition to thermal radiation, heat conduction through the glazing also occurs when there is a temperature difference between the outside environment and the interior. In the case of a moving vehicle, the glazing is further cooled by the airflow, which in turn leads to increased heat conduction to the outside.The total heat transfer can be described by the so-called heat transfer coefficient, usually referred to as the U-value, which takes into account the contributions of heat conduction and heat radiation, but also the influence of convection at the surfaces. The lower the U-value, the lower the heat transfer.

[0006] In electric vehicles, the consequences of significant heat loss are particularly critical because the automatic climate control (heating or cooling function) increases energy consumption, leading to a shorter range before the next necessary battery charge. Furthermore, the waste heat from a SAINT-GOBAIN SEKURIT FRANCE 2024340-WO-PCT cannot be used for heating.

[0007] It is used with an internal combustion engine, so the heating system must also be electrically operated.

[0008] Therefore, there is a need for composite panes with reduced heat transmission or better thermal insulation.

[0009] To reduce heat conduction, insulating glass units and vacuum insulating glass units are known, particularly in the field of architecture. In conventional insulating glass units, a spacer creates a gap between two panes of glass, which is filled with an inert gas. Vacuum insulating glass units (VIGs) consist of two spaced-apart panes of glass, with the space between them evacuated. Such vacuum insulating glass units are known, for example, from EP1978199A1 and W09804802A1. EP3878827A1 discloses a vehicle windshield designed as a vacuum insulating glass unit.

[0010] Thermochromic coatings are known to those skilled in the art; for example, reference is made to US2005147825A1 and US6084702A. Thermochromic coatings contain a thermochromic material, for example vanadium oxide, which, above a transition temperature, changes its optical properties, such as its reflectance to infrared radiation and / or its color, particularly due to changes in the Krista II structure.

[0011] The present invention is based on the objective of providing an improved composite disc with reduced heat transmission and better thermal insulation.

[0012] The problem is solved according to the invention by a composite disk according to independent claim 1. Advantageous embodiments are set forth in the dependent claims.

[0013] The composite pane according to the invention comprises an outer pane and an inner pane, which are bonded together over a surface. The composite pane has a thermochromic layer arranged between the outer pane and the inner pane. An evacuated cavity is also arranged between the thermochromic layer and the inner pane. SAINT-GOBAIN SEKURIT FRANCE 2024340-WO-PCT

[0014] The thermochromic layer transitions to a state of reduced IR radiation transmission when a certain temperature threshold is exceeded. At high outside temperatures, the thermochromic layer therefore reduces heat transfer through thermal radiation. The evacuated cavity, which can also be called a vacuum layer, gives the laminated glass unit thermal insulation properties similar to vacuum insulating glass and reduces heat transfer due to conduction. Overall, this significantly increases thermal comfort in the interior and reduces the need for cooling and heating systems. The thermochromic layer is located on the outside of the vacuum layer, so it is not thermally shielded by the vacuum layer and its state is essentially determined by the outside temperature. This improves the comfort of the occupants and reduces energy consumption.The vacuum layer also exhibits acoustically insulating properties, thus reducing the amount of external noise penetrating the interior and eliminating the need for costly acoustically insulating thermoplastic layers. These are significant advantages of the present invention.

[0015] The laminated glass pane is designed to separate an interior space (for example, the interior of a vehicle or a building) from the external environment within a window opening. For the purposes of this invention, the term "inner pane" refers to the pane facing the interior space. The term "outer pane" refers to the pane facing the external environment. Both the outer and inner panes have an outer and an interior surface, and a circumferential side edge surface extending between them. For the purposes of this invention, the term "outer surface" refers to the main surface intended to face the external environment when installed. For the purposes of this invention, the term "interior surface" refers to the main surface intended to face the interior space when installed.The inner surface of the outer pane and the outer surface of the inner pane face each other and are connected (surface connection). The outer surface of the outer pane and the inner surface of the inner pane face away from each other. The outer pane and the inner pane are preferably arranged substantially parallel to each other. SAINT-GOBAIN SEKURIT FRANCE 2024340-WO-PCT.

[0016] The outer and inner panes are preferably made of glass, particularly preferably of soda-lime glass, as is common for window panes. However, one or both panes can also be made of other types of glass, such as quartz glass, borosilicate glass, or aluminosilicate glass, or of rigid, clear plastics, such as polycarbonate or polymethyl methacrylate. The thicknesses of the outer and inner panes are preferably from 0.5 mm to 5 mm, and particularly preferably from 1 mm to 3 mm, and are independent of each other. The outer and inner panes can optionally be thermally or chemically tempered, partially tempered, or not tempered, independently of each other.

[0017] The composite pane according to the invention has an evacuated cavity (vacuum layer) which improves the thermal insulation properties of the composite pane. The vacuum layer preferably borders the inner pane. Part of the composite pane thus forms a type of vacuum insulating glass, with the inner pane preferably being part of this vacuum insulating glass.

[0018] The outer pane and the inner pane are connected to each other via a multi-layered connection structure, whereby the evacuated cavity is part of the connection structure or is embedded in the connection structure.

[0019] In a preferred embodiment, the evacuated cavity is formed between the inner pane and another pane. This second pane is arranged between the inner pane and the thermochromic layer. The second pane is separated from the inner pane by spacers. In other words, the laminated pane is equipped with another pane, which is arranged between the inner pane and the thermochromic layer and is connected to the inner pane by spacers, so that an evacuated cavity exists between the inner pane and the second pane. The inner pane and the second pane thus form the vacuum insulating glass unit.

[0020] The additional disc has a thickness of, for example, 0.3 mm to 5 mm, preferably 0.3 mm to 3 mm, particularly preferably 0.5 mm to 2 mm, and most preferably 0.5 mm to 1.5 mm. The additional disc preferably has a thinner disc than the outer and inner discs. SAINT-GOBAIN SEKURIT FRANCE 2024340- WO-PCT

[0021] The second pane is preferably made of glass. Soda-lime glass can also be used. In particular, a very thin second pane (for example, with a thickness of 0.5 mm to 1 mm) can also be made of aluminosilicate glass, which is preferably chemically tempered. Alternatively, the second pane can also be made of a rigid, clear plastic, such as polycarbonate or polymethyl methacrylate.

[0022] The gap (cavity) between the inner pane and the outer pane preferably has a thickness of 0.1 mm to 1 mm, particularly preferably 0.2 mm to 0.5 mm. This achieves good thermal insulation without significantly increasing the thickness of the composite pane. The thickness of the gap corresponds to the distance between the facing surfaces of the inner pane and the outer pane.

[0023] According to the invention, the cavity is evacuated. This means that a negative pressure prevails in the cavity, i.e., a pressure that is lower than the ambient pressure. The pressure in the cavity is preferably at most 100 mbar, more preferably at most 10 mbar. The pressure can, for example, range from 0.01 mbar to 100 mbar, preferably from 0.1 mbar to 10 mbar.

[0024] The spacers ensure that the inner disk and the outer disk do not deform despite the negative pressure between them. The spacers preferably keep the distance between the inner disk and the outer disk constant, so that the inner disk and the outer disk are arranged parallel to each other.

[0025] The spacers preferably comprise a plurality of spacer columns. The spacer columns are distributed (preferably uniformly) over the surface of the inner pane and the outer pane. The number of spacer columns and their spacing depend on the thickness of the panes and the negative pressure in the space between them. The thinner the panes (and the lower the pressure in the space between them), the more prone they are to deformation, necessitating a greater number of spacer columns. SAINT-GOBAIN SEKURIT FRANCE 2024340- WO-PCT

[0026] The spacer columns are preferably transparent so as not to significantly impair the view through the laminated glass. They are preferably made of glass or plastic.

[0027] The spacers particularly preferably also include a circumferential spacer in an edge region between the inner pane and the other pane. The circumferential spacer extends around the perimeter of an edge region between the inner pane and the other pane. The evacuated space (cavity) is bounded by the inner pane, the other pane, and the circumferential spacer. The spacer is made, for example, of glass, plastic, metal, or a metal alloy.

[0028] To maintain the vacuum (more precisely, the negative pressure) in the cavity, the vacuum insulating glass unit, formed from an inner pane and another pane, preferably has a gas-tight edge seal. The surrounding spacer (if present) can itself act as an edge seal, or the vacuum insulating glass unit can be equipped with an additional edge seal, for example made of glass, a metal or metal alloy (e.g., stainless steel, silver, or copper), or a gas-tight plastic.

[0029] The second disk (more precisely, its surface facing away from the inner disk) is connected to the outer disk (more precisely, to its surface facing the inner disk) via an intermediate layer. The intermediate layer consists of at least one bonding layer. The thermochromic layer is preferably arranged between the second disk and the outer disk. The thermochromic layer can be in contact with the outer disk or the second disk, or spaced apart from both and embedded in the intermediate layer.

[0030] In principle, it is also conceivable that the laminated glass unit contains a vacuum insulating glass unit consisting of an outer and an inner pane, which are connected to each other via spacers and have an intermediate, evaluated cavity, with the vacuum insulating glass unit being arranged between the outer and inner panes. The outer pane is connected to the outer pane SAINT-GOBAIN SEKURIT FRANCE 2024340-WO-PCT via an outer intermediate layer (consisting of at least one bonding layer), and the inner pane is connected to the inner pane via an inner intermediate layer (consisting of at least one bonding layer).

[0031] In a first preferred embodiment of the invention, the thermochromic layer is designed as a thermochromic coating and is arranged on the inner surface of the outer pane facing the inner pane. The outer pane, more precisely the inner surface of the outer pane (or the thermochromic layer applied thereto), is connected to the other pane via at least one (preferably exactly one) bonding layer. The at least one bonding layer forms the aforementioned intermediate layer.

[0032] In a second preferred embodiment of the invention, the thermochromic layer is designed as a thermochromic film. The thermochromic film comprises a thermochromic coating on a carrier film. It is irrelevant whether the thermochromic coating faces the outer pane, the vacuum layer, or the inner pane. It may be preferred that the thermochromic coating faces the outer pane so that it is better exposed to the outside temperature and is not additionally thermally shielded by the carrier film.

[0033] In a third preferred embodiment of the invention, the thermochromic layer is also designed as a thermochromic film. In this case, however, the thermochromic film comprises (or is formed from) a polymer film in which thermochromic particles are embedded. In other words, the polymer film contains thermochromic additives, so that the polymer film functions as a thermochromic layer within the meaning of the invention.

[0034] In the second and third preferred embodiments, the thermochromic film is embedded in the intermediate layer. It is connected to the outer pane via (at least, preferably exactly) a first bonding layer, more precisely to the inner surface of the outer pane, and to the other pane via (at least, preferably exactly) a second bonding layer.

[0035] In a fourth preferred embodiment of the invention, the outer pane, more precisely the inner surface of the outer pane, is connected to the other pane via the intermediate layer. The intermediate layer comprises at least one SAINT-GOBAIN SEKURIT FRANCE 2024340-WO-PCT

[0036] The bonding layer preferably consists of exactly one bonding layer. The outer pane is thus connected to the other pane via (at least, preferably exactly) one bonding layer. Thermochromic particles are embedded in this bonding layer, so that the bonding layer forms the thermochromic layer. In other words, the bonding layer contains thermochromic additives, so that the bonding layer functions as a thermochromic layer according to the invention.

[0037] It is also conceivable that the thermochromic layer is designed as a thermochromic coating and arranged on the surface of the second pane facing the outer pane or the intermediate layer. The second pane (or the thermochromic coating applied to it) is connected to the outer pane via the intermediate layer, more precisely to the inner surface of the outer pane. The intermediate layer comprises at least one bonding layer and preferably consists of exactly one bonding layer. Thus, the second pane is connected to the outer pane via (at least, preferably exactly) one outer bonding layer. However, since the second pane is typically thinner than the outer pane and provides less stability, this configuration is generally less preferred.

[0038] In the third and fourth preferred embodiments, the thermochromic layer is realized by embedding thermochromic particles in a polymer film or compound layer. This can be preferable to the first and second embodiments, in which the thermochromic layer is realized as a thermochromic coating. Since in this case there is no continuous layer of thermochromic material, better transparency to electromagnetic high-frequency radiation is achieved, for example, to radio, mobile phone, or GPS signals.

[0039] In the first preferred embodiment, the laminated glass pane comprises, in the specified order: the outer pane with the thermochromic coating, the bonding layer, the second pane, the spacers forming the cavity, and the inner pane. SAINT-GOBAIN SEKURIT FRANCE 2024340- WO- PCT

[0040] In the second and third preferred embodiments, the composite disc comprises, in the specified order: the outer disc, the first bonding layer, the thermochromic film, the second bonding layer, the further disc, the spacers forming the cavity, and the inner disc.

[0041] In the fourth preferred embodiment, the composite disc comprises, in the specified order: the outer disc, the bonding layer with the embedded thermochromic particles, the further disc, the spacers which form the cavity, the inner disc.

[0042] In particularly preferred embodiments, the laminated glass consists structurally only of the elements specified. The outer pane, the inner pane, and / or the additional pane (or the bonding layer(s) or further layers of the intermediate layer) may also be provided with standard coatings or imprints.

[0043] The bonding layers serve to adhesively connect the components of the composite disc between which they are arranged. The bonding layers are preferably each composed of one or more thermoplastic layers. These thermoplastic layers can alternatively be referred to as thermoplastic sheets.

[0044] The thermoplastic layers are preferably based on polyvinyl butyral (PVB), ethylene vinyl acetate (EVA), or polyurethane (PU), or on mixtures, copolymers, or derivatives thereof, particularly preferably on PVB. This means that the layer contains the said polymer to a large extent (proportion greater than 50 wt%). In addition to the polymer, the layer may contain other additives, such as plasticizers, UV absorbers (SAINT-GOBAIN SEKURIT FRANCE 2024340-WO-PCT), or stabilizers. Each thermoplastic layer is preferably formed from a thermoplastic film. The thickness of each film is preferably from 0.2 mm to 1 mm. For example, PVB films with standard thicknesses of 0.38 mm or 0.76 mm can be used.

[0045] The bonding layers can alternatively be designed as adhesive layers. Optically clear adhesives (OCAs) are preferred. This is particularly advantageous with regard to the aesthetic appearance of the vehicle roof window. OCAs are well known to those skilled in the art. They are characterized in particular by their high optical quality. They are especially common where high optical quality is necessary so that the adhesive layer is virtually invisible, for example, in displays or touch panels. Optically clear adhesives are characterized in particular by high light transmission and the fact that distortion-free visibility is possible. The optically clear adhesive is preferably a two-component polyurethane adhesive, a one-component acrylate adhesive, a one-component silicone adhesive, or a one-component acrylate hybrid adhesive.

[0046] In principle, a combination is also conceivable, wherein at least one bonding layer consists of at least one thermoplastic layer and at least one other bonding layer is designed as an adhesive layer.

[0047] The thermochromic layer contains a thermochromic material or (in the case of a thermochromic coating) is based on a thermochromic material. Upon exceeding a certain transition temperature, the thermochromic layer changes its reflectance and / or absorptivity towards infrared radiation, and thus its transmittance towards infrared radiation (especially in the infrared spectral range of solar radiation). This change is primarily caused by a change in the crystal or molecular structure of the thermochromic material. The change in IR transmittance can be accompanied by a change in absorption in the visible spectral range and therefore by a color change. Upon exceeding the transition temperature, a transition from a dielectric to an electrically conductive state can occur.

[0048] Or, put another way: thermochromic materials are known for changing their color when a transition temperature is exceeded. The present SAINT-GOBAIN SEKURIT FRANCE 2024340-WO-PCT

[0049] The invention utilizes the fact that this color change is also accompanied by a change in transmittance in the IR range. Thus, the thermochromic layer can be used to reduce the transmittance to the infrared components of solar radiation at high outside temperatures, thereby reducing heat gain through the laminated glass into the interior.

[0050] Thermochromic materials are well-known to those skilled in the art. Vanadium oxide, for example, is widely used. Alternatively, zinc oxide, titanium oxide, or zinc sulfide can be employed. In principle, any thermochromic material can be used. Inorganic thermochromic materials may be preferred over organic ones, for example, due to their higher chemical stability.

[0051] The thermochromic material can contain dopants. Such dopants, for example niobium, tantalum, molybdenum, iridium, or tungsten, can influence the transition temperature, in particular lower it. This makes it possible to precisely adjust the transition temperature according to the requirements of the specific application.

[0052] The transition temperature is preferably in the range of 10°C to 45°C, particularly preferably from 15°C to 25°C.

[0053] The transmittance of the thermochromic layer is determined as the integral transmittance over a wavelength range of 800 nm to 1300 nm, measured with a standard D65 light source and a 2° detector, at an angle of incidence of 0° (to the surface normal). When the transmittance TRIR is plotted against the temperature T, a first plateau (constant transmittance) is observed below the transition temperature, and a second plateau above the transition temperature. By fitting a horizontal line, the function value of the first plateau, TRIR, 1, and the value of the second plateau, TRIR, 2, can be determined. TRIR, 1 is the larger value in absolute value because the transmittance decreases when the transition temperature is exceeded.In a transition region, the transmittance value TRIR changes from the first plateau TRIR, 1 to the second plateau TRIR, 2, with an inflection point occurring at the transition temperature To, where the graph changes its direction of curvature. SAINT-GOBAIN SEKURIT FRANCE 2024340-WO-PCT.

[0054] From such a plot, the function value TRIR(TO) at the transition temperature can be determined as the average between the first plateau and the second plateau; thus, TRIR(TO) = TRIR, 2 + 0.5*(TRIR .TRIR, 2). The transition temperature To is then the temperature at which this function value TRIR(TO) occurs.

[0055] The difference between the first plateau TRIR, 1 and the second plateau TRIR, 2 is typically at least 5%, preferably at least 10%, and particularly preferably at least 20%. This applies to the thermochromic layer as such.

[0056] As already described, the thermochromic layer can be designed as a thermochromic coating in certain embodiments of the invention. Such a coating based on (optionally doped) thermochromic material typically has a thickness of a few nanometers, preferably from 1 nm to 200 nm, and particularly preferably from 1 nm to 150 nm.

[0057] Such a coating can be achieved by covering the entire surface with thermochromic particles, particularly thermochromic nanoparticles. This coating can be produced, for example, by wet coating processes such as dip coating. Alternatively, it can also be produced by vapor deposition, such as magnetron sputtering. To improve transparency against electromagnetic radiation, especially antenna signals, locally confined areas can be excluded from the coating to function as so-called communication or data transmission windows.

[0058] As previously described, in certain other embodiments of the invention, the thermochromic layer can be formed by a polymer film or a compound layer containing thermochromic particles as inclusions. Here, too, thermochromic nanoparticles are preferred. The proportion of thermochromic particles in said polymer film or compound layer is, for example, from 1 wt.% to 30 wt.%. Since there is no full-surface coverage with thermochromic particles, this can result in better transparency to radio frequency signals, which is advantageous because it eliminates the need to provide separate data transmission windows to ensure the transmission of, for example, mobile phone radiation. SAINT-GOBAIN SEKURIT FRANCE 2024340-WO-PCT

[0059] The interior surface of the inner pane, facing away from the outer pane, is preferably provided with an emissivity-reducing coating. Emissivity-reducing coatings are also known as heat-radiation-reflecting coatings, low-emissivity coatings, or LowE (low emissivity) coatings. Emissivity is the measure that indicates how much heat radiation the pane, in its installed position, emits into an interior space compared to an ideal heat radiator (a black body). Emissivity-reducing coatings serve to prevent heat radiation from entering the interior space (IR components of solar radiation and, in particular, the thermal radiation of the pane itself) and also from radiating heat out of the interior space. They exhibit reflective properties with respect to infrared radiation, especially heat radiation in the spectral range of 5 pm to 50 pm (see also standard DIN EN 12898:2019-06).This effectively improves thermal comfort in the interior. The emissivity-reducing coatings can at least partially reflect the heat radiation emitted from the entire pane towards the interior at high outside temperatures and in direct sunlight. At low outside temperatures, they can reflect the heat radiation emitted from the interior, thus reducing the effect of the cold pane as a heat sink. The emissivity-reducing coating further enhances thermal comfort in the interior.

[0060] The emissivity-reducing coating is typically a transparent stack of thin films. The emissivity-reducing coating preferably comprises at least one, and more preferably exactly one, electrically conductive layer, which provides the IR-reflective properties. The conductive layer is preferably based on a transparent conductive oxide (TCO), in particular indium tin oxide (ITO), alternatively indium zinc mixed oxide (IZO), gallium-doped tin oxide (GZO), fluorine-doped tin oxide (FTO, SnO₂:F), antimony-doped tin oxide (ATO, SnO₂:Sb), or niobium-doped titanium oxide (TiO₂:Nb). Unlike metals, TCOs are not susceptible to corrosion, so they can be used on the exposed inner surface of the inner disc.In addition to the conductive layer, the coating typically has dielectric layers (for example, based on silicon oxide or nitride), which serve in particular to optimize the optical properties (for example, light transmission) or as SAINT-GOBAIN SEKURIT FRANCE 2024340- WO- PCT.

[0061] Barrier layers serve to regulate oxygen diffusion during the deposition of the coating.

[0062] The emissivity-reducing coating is preferably applied over the entire surface of the inner pane, optionally with the exception of a surrounding uncoated edge area.

[0063] The laminated glass is designed as a glazing element and therefore has a transparent viewing area. This viewing area allows a view through the laminated glass. The laminated glass can be completely transparent, so that the viewing area encompasses the entire laminated glass. The laminated glass preferably has a light transmission of at least 3% in the viewing area, and particularly preferably at least 5% or even at least 6%. Light transmission here refers to the total transmission, determined by the procedure for testing the light transmittance of motor vehicle windows specified in ECE-R 43, Annex 3, Section 9.1.

[0064] The transparent viewing area allows you to see through the laminated glass. However, the laminated glass can be tinted or colored to, for example, reduce glare for people inside or the transmission of heat radiation.

[0065] The laminated glass can also have an opaque masking area through which no light can pass or see through. Such a masking area is particularly common in vehicle windows. It is typically formed by an opaque printed coating on at least one of the surfaces of the inner and / or outer pane, for example, on the interior surface of the outer pane. An enamel printing paste containing glass frits and a pigment (especially black pigment) is printed onto the surface, for example, using a screen printing process, and then fired on. The masking area typically comprises a circumferential edge of the laminated glass, surrounding a central viewing area like a frame. However, the masking area can also include additional areas, which may, for example, act as cross braces for the frame-like edge.The laminated glass preferably has a light transmission of at most 1% in the masking area, particularly preferably at most 0.1%, and especially essentially 0%. SAINT-GOBAIN SEKURIT FRANCE 2024340-WO-PCT.

[0066] Alternatively, a masking area can also be formed by making a thermoplastic layer of the intermediate layer opaque or by embedding an opaque film or plate in the intermediate layer.

[0067] The thermochromic layer and the evacuated cavity (the vacuum layer) preferably completely cover the viewing area of ​​the laminated glass. The same applies to the emissivity-reducing coating, if present. If the thermochromic layer is designed as a thermochromic coating, local areas serving as communication or data transmission windows may not be coated. Complete coverage (except for any communication or data transmission windows) is advantageous for reducing heat transfer through the laminated glass. Typically, the thermochromic layer, the vacuum layer, and, if applicable, the emissivity-reducing coating extend beyond the viewing area into the masking area.They can extend independently of each other to the side edge of the composite pane or end in the masking area, with their edges being spaced away from the side edge of the composite pane.

[0068] The composite disc according to the invention is, in a preferred embodiment, a vehicle roof disc. The vehicle can be any means of transport for traffic on land, water, or in the air, for example, a ship, aircraft, rail vehicle, or motor vehicle (such as a passenger car or truck). The vehicle roof disc is most preferably a roof disc of a passenger car or truck.

[0069] The composite glass is particularly preferred as the roof window of an electric vehicle. Due to its low heat transmission, the composite glass according to the invention improves thermal comfort in the vehicle interior, thus reducing the need for heating (at low outside temperatures) and cooling (at high outside temperatures) devices. This saves energy, which is particularly advantageous for electric vehicles with regard to the operating time of the on-board battery.

[0070] The laminated glass pane can be flat, cylindrical, or spherically curved. Spherically curved laminated glass panes are common in passenger car windows. Flat laminated glass panes are found particularly in architecture, but also in the SAINT-GOBAIN SEKURIT FRANCE 2024340-WO-PCT.

[0071] Vehicle sector, for example as glazing for buses or (for example agricultural or construction) commercial vehicles.

[0072] The outer pane, the inner pane, the bonding layers, and any additional panes can be clear, tinted, or colored independently of one another. In the case of vehicle roof windows, strong tints are common, reducing light transmission through the laminated glass (more precisely, through the viewing area) to below 50%, particularly below 20%. This is preferably achieved by a correspondingly tinted outer pane, inner pane, bonding layer, and / or additional pane, and especially preferably by a correspondingly tinted outer pane, inner pane, and / or bonding layer. The strong tint reduces solar radiation, thus preventing the interior from heating up and avoiding glare. It may be preferred that the inner pane be tinted or colored.

[0073] The composite disc can be manufactured by stacking the individual layers in the intended sequence into a layer stack and then laminating them together. This can be achieved using well-known methods, such as autoclave processes, vacuum bag processes, vacuum ring processes, calender processes, vacuum laminators, or combinations thereof. The bonding of the outer and inner discs via the intermediate layer typically occurs under the influence of heat, vacuum, and / or pressure.

[0074] The invention further comprises the use of a composite pane according to the invention as glazing for a vehicle, a building, or an interior space, or as a component of such glazing, in particular as a roof window pane (vehicle roof pane) of means of transport for travel on land, in the air, or on water. The vehicle roof pane can, in principle, be used in any land, air, or water vehicle, preferably in motor vehicles or rail vehicles, particularly preferably in passenger cars or trucks, especially in electric vehicles (electric passenger cars). SAINT-GOBAIN SEKURIT FRANCE 2024340- WO-PCT

[0075] The invention is explained in more detail with reference to a drawing and exemplary embodiments. The drawing is a schematic representation and not to scale. The drawing does not limit the invention in any way. It shows:

[0076] Fig. 1 is a top view of an embodiment of the composite disk according to the invention, Fig. 2 is a cross-section along XX' through the composite disk from Figure 1 ,

[0077] Fig. 3 shows a cross-section along XX' through a further embodiment of the composite disk according to the invention,

[0078] Fig. 4 shows a cross-section along XX' through a further embodiment of the composite disk according to the invention.

[0079] Figures 1 and 2 each show a detail of an embodiment of the composite glass according to the invention. The composite glass is designed as a vehicle roof window. It comprises an outer pane 1 and an inner pane 2, which are bonded together over their entire surface. The outer pane 1 and the inner pane 2 are made of soda-lime glass. The outer pane 1 has a thickness of 2.1 mm, and the inner pane 2 has a thickness of 1.6 mm. In its installed position, the outer pane 1 faces the external environment, and the inner pane 2 faces the vehicle interior.

[0080] The laminated glass pane has an opaque masking area M, which is arranged around the perimeter and surrounds a central transparent viewing area D like a frame. A black cover print 8 is applied to the inner surface of the outer pane 1, facing the inner pane 2, within the masking area M. The viewing area D allows a view through the laminated glass pane, while the opaque masking area M is opaque.

[0081] The laminated glass pane also includes another pane 5, which is a thin glass pane made of chemically tempered aluminosilicate glass with a thickness of, for example, 0.7 mm. This additional pane 5 is positioned between the outer pane 1 and the inner pane 2 and is connected to the inner pane 2 via a circumferential spacer 4a and a plurality of spacer columns 4b evenly distributed across its surface, so that a cavity 4 with a thickness of, for example, 0.3 mm is formed between the inner pane 2 and the additional pane 5. This cavity 4 is evacuated – the inner pane 2 and the additional pane 5 together form a SAINT-GOBAIN SEKURIT FRANCE 2024340-WO-PCT

[0082] Vacuum insulating glazing. The spacer columns 4b are made of glass or a transparent plastic. The circumferential spacer 4a is made of plastic. Furthermore, the circumferential spacer 4a is equipped with an edge seal (not shown) which seals the cavity 4 gas-tight.

[0083] The second disc 5 is connected to the outer disc 1 via a bonding layer. The bonding layer is designed as a single thermoplastic layer 6, which is formed from a PVB film with a thickness of 0.76 mm.

[0084] A thermochromic layer 3 is applied as a coating to the interior surface of the outer pane 1, facing the inner pane 2. The thermochromic layer

[0085] Layer 3 completely covers the transparent area D and extends from there into the masking area M. In the masking area M, the thermochromic layer 3 can be positioned below or above the masking print 8.

[0086] The thermochromic layer 3 changes its transmittance to IR radiation when a transition temperature is exceeded, decreasing its transmittance. At high outside temperatures, this reduces the transmission of infrared components of solar radiation, thus preventing the interior from heating up too quickly. The evacuated cavity

[0087] Layer 4 is thermally insulating and reduces heat conduction through the laminated glass, similar to vacuum insulating glazing. Overall, heat transfer through the laminated glass is significantly reduced, and thermal comfort in the vehicle interior is considerably improved. The interior requires less cooling from the air conditioning system. At low outside temperatures, the thermochromic layer 3 exhibits a higher transmittance to infrared radiation, which is advantageous with regard to preventing the interior from being heated by solar radiation. The thermally insulating evacuated cavity 4 reduces heat loss from the interior through conduction. This also contributes to improved thermal comfort in the interior, which requires less heating. The reduced need to operate cooling and heating systems further saves energy.The evacuated cavity 4 also leads to an improved acoustic shielding effect of the composite disc.

[0088] An additional emissivity-reducing coating 7 is applied to the interior surface of the inner pane 2, the side facing away from the outer pane 1. The emissivity-reducing coating 7 covers the entire surface. At high outside temperatures, the SAINT-GOBAIN SEKURIT FRANCE 2024340-WO-PCT emissivity-reducing coating 7 reflects the heat radiation emitted by the heated laminated pane into the interior, and at low outside temperatures, it reflects the heat radiation emitted from the interior. The emissivity-reducing coating 7 thus further reduces heat transmission through the laminated pane due to IR and thermal radiation.

[0089] Figure 3 shows a further embodiment of the composite disc according to the invention. The outer disc 1 with the cover print 8, the further disc 5, the spacer 4a and the spacer columns 4b, via which the further disc 5 is connected to the inner disc 2, and the inner disc 2 with the emissivity-reducing coating 7 are designed in the same way as in the embodiment of Figures 1 and 2.

[0090] The laminated glass differs from the previous design by the integration of the thermochromic layer 3. This layer is designed as a thermochromic film. The thermochromic film is bonded to the outer glass pane 1 via a first bonding layer and to the second glass pane 5 via a second bonding layer. The bonding layers are each formed as individual thermoplastic layers 6a and 6b (first thermoplastic layer 6a, second thermoplastic layer 6b). The thermoplastic layers 6a and 6b are each made of a PVB film with a thickness of 0.38 mm.

[0091] The thermochromic film can be designed in various ways. It can consist of a carrier film, for example, based on PET with a thickness of 100 pm, which is coated with a thermochromic layer. Alternatively, it can be made from a polymer film, for example, based on PET with a thickness of 100 pm, to which thermochromic particles have been added.

[0092] Figure 4 shows a further embodiment of the composite disc according to the invention. The outer disc 1 with the cover print 8, the further disc 5, the spacer 4a and the spacer columns 4b, via which the further disc 5 is connected to the inner disc 2, and the inner disc 2 with the emissivity-reducing coating 7 are designed in the same way as in the embodiments of Figures 1 to 3.

[0093] The composite pane differs from previous designs by the integration of the thermochromic layer 3. The further pane 5 is connected to the outer pane 1 via a bonding layer, which is a single thermoplastic SAINT-GOBAIN SEKURIT FRANCE 2024340- WO- PCT

[0094] Layer 6 is formed. The thermoplastic layer 6 is formed from a PVB film with a thickness of 0.76 mm. Thermochromic particles are added to this thermoplastic layer 6, so that the thermoplastic layer 6 simultaneously functions as thermochromic layer 3.

[0095] SAINT-GOBAIN SEKURIT FRANCE 2024340-WO-PCT

[0096] Reference symbol list:

[0097] (1) Outer pane

[0098] (2) Inner disc

[0099] (3) thermochromic layer

[0100] (4) evacuated cavity

[0101] (4a) circumferential spacer

[0102] (4b) Spacer columns

[0103] (5) another disc

[0104] (6) thermoplastic layer

[0105] (6a) first thermoplastic layer

[0106] (6b) second thermoplastic layer

[0107] (7) emissivity-reducing coating

[0108] (8) Cover printing

[0109] (D) Viewing area of ​​the laminated glass

[0110] (M) Masking area of ​​the composite disc

[0111] X - X' Intersection line

Claims

22 SAINT-GOBAIN SEKURIT FRANCE 2024340-WO-PCT Patent claims 1. Composite disc comprising an outer disc (1) and an inner disc (2) which are bonded together over a surface, wherein the composite disc has a thermochromic layer (3) which is arranged between the outer disc (1) and the inner disc (2), and wherein an evacuated cavity (4) is arranged between the thermochromic layer (3) and the inner disc (2).

2. Composite disc according to claim 1, wherein the evacuated cavity (4) is formed between the inner disc (2) and a further disc (5) which is arranged between the inner disc (2) and the thermochromic layer (3) and is separated from the inner disc (2) by spacers (4a, 4b).

3. Composite pane according to claim 2, wherein the further pane (5) is made of soda-lime glass or chemically tempered aluminosilicate glass and preferably has a thickness of 0.5 mm to 1.5 mm.

4. Composite disc according to claim 2 or 3, wherein the spacers (4a, 4b) - a circumferential spacer (4a) in an edge area between the outer pane (1) and the other pane (5) and - comprise a plurality of spacer columns (4b).

5. Composite disc according to one of claims 2 to 4, wherein the thermochromic layer (3) is formed as a thermochromic coating on the surface of the outer disc (1) facing the inner disc (2) and wherein the outer disc (1) is connected to the further disc (5) via a bonding layer.

6. Composite disc according to one of claims 2 to 4, wherein the thermochromic layer (3) is designed as a thermochromic film comprising a thermochromic coating on a carrier film, and wherein the thermochromic film is connected to the outer disc (1) via a first bonding layer and to the further disc (5) via a second bonding layer. SAINT-GOBAIN SEKURIT FRANCE 2024340-WO-PCT 7. Composite disc according to one of claims 2 to 4, wherein the thermochromic layer (3) is designed as a thermochromic film comprising a polymer film in which thermochromic particles are embedded, and wherein the thermochromic film is connected to the outer disc (1) via a first bonding layer and to the further disc (5) via a second bonding layer.

8. Composite disc according to one of claims 2 to 4, wherein the outer disc (1) is connected to the further disc (5) via a bonding layer and wherein thermochromic particles are embedded in the bonding layer, such that the bonding layer forms the thermochromic layer (3).

9. Composite disc according to one of claims 5 to 8, wherein the bonding layers are formed as thermoplastic layers (6; 6a, 6b), preferably based on polyvinyl butyral (PVB), ethylene vinyl acetate (EVA) or polyurethane (PU), or as adhesive layers, preferably based on an optically clear adhesive (OCA).

10. Composite disc according to any one of claims 1 to 9, wherein the evacuated cavity (4) has a thickness of 0.1 mm to 1 mm, preferably 0.2 mm to 0.5 mm, and a pressure of at most 100 mbar, particularly preferably at most 10 mbar.

11. Composite disc according to one of claims 1 to 10, wherein the thermochromic layer (3) transitions from a state of higher transmission of IR radiation to a state of lower transmission of IR radiation upon exceeding a transition temperature, and wherein the transition temperature is from 10°C to 45°C, preferably from 15°C to 25°C.

12. Composite pane according to one of claims 1 to 11, wherein the surface of the inner pane (2) facing away from the outer pane (1) is provided with an emissivity-reducing coating (7). SAINT-GOBAIN SEKURIT FRANCE 2024340-WO-PCT 13. Laminated glass pane according to any one of claims 1 to 12, wherein the outer pane (1) and the inner pane (2) are made of soda-lime glass and preferably have a thickness of 1 mm to 3 mm.

14. Laminated glass pane according to any one of claims 1 to 13, wherein a transparent or translucent viewing area (D) is surrounded by an opaque masking area (M) in a frame-like manner, and wherein the thermochromic layer (3), the evacuated cavity (4), and optionally the emissivity-reducing coating (7) completely cover the viewing area (D).

15. Composite disc according to one of claims 1 to 14, which is a vehicle roof disc, preferably a roof disc of an electric vehicle.

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