Composite pane with aerogel ply and thermochromic layer

Abstract

The invention relates to a composite pane comprising an outer pane (1) and an inner pane (2) which are connected together via an intermediate layer (3), wherein the intermediate layer (3) contains an aerogel ply (5), and between the aerogel ply (5) and the outer pane (1) is a thermochromic layer (4).

Description

[0001] SAINT-GOBAIN SEKURIT FRANCE 2024335-WO-PCT

[0002] Composite lens with aerogel layer and thermochromic layer

[0003] The invention relates to a composite disc equipped with an aerogel layer and a thermochromic layer.

[0004] Laminated glass is commonly used as a component of glazing. It is widely used in the automotive sector, particularly as windshields and roof windows, and increasingly as side and rear windows. However, it can also be used in architecture as building glazing or as a component thereof. Such laminated glass typically consists of an outer pane and an inner pane bonded together by a thermoplastic interlayer.

[0005] When it comes to glazing, professionals always strive to reduce heat transfer to improve thermal comfort in the interior. This aims to prevent the interior from heating up too much in high outdoor temperatures, thus reducing the need for cooling devices like air conditioning, and conversely, to prevent the interior from cooling down too quickly in low outdoor temperatures, thus reducing the need for heating. Suitable glazing can enhance the well-being of the occupants while simultaneously reducing energy consumption.

[0006] 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 includes the contributions of heat conduction and heat radiation, but also the SAINT-GOBAIN SEKURIT FRANCE 2024335-WO-PCT.

[0007] The influence of convection at the surfaces is taken into account. The lower the ll value, the lower the thermal transmittance.

[0008] In electric vehicles, the consequences of significant heat loss are particularly critical because the automatic climate control (heating and cooling functions) increases energy consumption, leading to a shorter range before the next necessary battery charge. Furthermore, the waste heat from a combustion engine cannot be used for heating, meaning the heating system must also be electrically powered.

[0009] Therefore, there is a need for composite panes with reduced heat transmission or better thermal insulation.

[0010] Aerogels are highly porous solids known for their very low thermal conductivity and heat-insulating properties. WO2012154602A1 discloses an insulating glass unit with an aerogel layer. US2010146880A1 discloses a building roof panel consisting of two glass panes and an aerogel layer between them. EP3381881A1 discloses a laminated glass unit consisting of two glass panes and a thermally insulating layer between them, which may be an aerogel layer. WO2024193919A1 discloses a laminated glass unit with an aerogel layer and photovoltaic components.

[0011] Thermochromic coatings are also 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.

[0012] The present invention is based on the objective of providing an improved composite disc with reduced heat transmission and better thermal insulation.

[0013] The problem is solved according to the invention by a composite disc according to independent claim 1. Advantageous embodiments are described in the dependent claims. SAINT-GOBAIN SEKURIT FRANCE 2024335-WO-PCT

[0014] The composite disc according to the invention comprises an outer disc and an inner disc, which are bonded together over a surface area via an intermediate layer. The intermediate layer contains an aerogel layer. A thermochromic layer is arranged between the aerogel layer and the outer disc. The thermochromic layer can be in contact with the outer disc or the aerogel layer, or spaced apart from both.

[0015] 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 aerogel layer has thermally insulating properties and reduces heat conduction through the laminated glass. Overall, this significantly increases thermal comfort in the interior and reduces the need for cooling and heating systems. The thermochromic layer is positioned on the outside of the aerogel layer, so it is not thermally shielded by the aerogel layer and its state is essentially determined by the outside temperature. This improves the well-being of the occupants and reduces energy consumption.The aerogel layer also acts as a thermal trap, storing a certain amount of thermal energy, which leads to additional heating of the outer pane and the thermochromic layer. This shortens the transition time between the states of the thermochromic layer, and the radiation-reflecting effect begins sooner. The aerogel layer also exhibits acoustic insulating properties, reducing the amount of external noise penetrating the interior and eliminating the need for costly acoustically insulating thermoplastic layers. The aerogel layer is very lightweight, resulting in a comparatively low overall weight for the composite pane. These are significant advantages of the present invention.

[0016] The laminated glass pane is designed to separate an interior space (for example, the interior of a vehicle, a building, or a room) 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" (SAINT-GOBAIN SEKURIT FRANCE 2024335- WO-PCT) 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 via the intermediate layer. The outer surface of the outer pane and the inner surface of the inner pane face away from each other.

[0017] 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.

[0018] The aerogel layer is part of the interlayer of the laminated glass. It is connected to the outer glass pane via a portion of the interlayer, which can also be referred to as the outer interlayer, and preferably to the inner glass pane via another portion of the interlayer, which can also be referred to as the inner interlayer. Both the outer and inner interlayers consist of at least one bonding layer. Alternatively, the aerogel layer can be produced directly on the inner glass pane, eliminating the need for an inner bonding layer.

[0019] In a first preferred embodiment of the invention, the thermochromic layer is designed as a thermochromic coating and is arranged on the interior surface of the outer pane facing the intermediate layer.

[0020] The aerogel layer is connected to the outer pane via the outer intermediate layer, more precisely to the inner surface of the outer pane (or the thermochromic coating applied to it). The outer intermediate layer comprises at least one bonding layer and preferably consists of SAINT-GOBAIN SEKURIT FRANCE 2024335-WO-PCT, specifically exactly one bonding layer. The aerogel layer is thus connected to the outer pane via (at least, preferably exactly) one outer bonding layer.

[0021] 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 or the aerogel layer. 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.

[0022] 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.

[0023] In the second and third preferred embodiments, the thermochromic film is embedded in the outer intermediate layer. It is connected to the outer pane via (at least, preferably exactly) a first outer bonding layer, more precisely to the inner surface of the outer pane, and to the aerogel layer via (at least, preferably exactly) a second outer bonding layer.

[0024] In a fourth preferred embodiment of the invention, the aerogel layer is connected to the outer pane via the outer intermediate layer, more precisely to the inner surface of the outer pane. The outer intermediate layer comprises at least one bonding layer and preferably consists of exactly one bonding layer. The aerogel layer is thus connected to the outer pane via (at least, preferably exactly) one outer bonding layer. Thermochromic particles are embedded in this outer bonding layer, so that the outer bonding layer forms the thermochromic layer. In other words, the outer bonding layer contains thermochromic additives, so that the outer bonding layer functions as a thermochromic layer within the meaning of the invention. SAINT-GOBAIN SEKURIT FRANCE 2024335-WO-PCT

[0025] It is also conceivable that the thermochromic layer is designed as a thermochromic coating and arranged on the surface of the aerogel layer facing the outer pane or the outer intermediate layer, which can be described as the fifth preferred embodiment of the invention. The aerogel layer (or the thermochromic coating arranged thereon) is connected to the outer pane via the outer intermediate layer, more precisely to the inner surface of the outer pane. The outer intermediate layer comprises at least one bonding layer and preferably consists of exactly one bonding layer. The aerogel layer is thus connected to the outer pane via (at least, preferably exactly) one outer bonding layer.

[0026] In all the aforementioned preferred embodiments (i.e., the first, second, third, fourth, and fifth preferred embodiments), the aerogel layer is preferably connected to the inner disk via the inner intermediate layer, more precisely to the outer surface of the inner disk. The inner intermediate layer comprises at least one bonding layer and preferably consists of exactly one bonding layer. Thus, the aerogel layer is connected to the inner disk via (at least, preferably exactly) one inner bonding layer.

[0027] In the first preferred embodiment, the composite disc comprises, in the specified order: the outer disc with the thermochromic coating, the outer bonding layer, the aerogel layer, an inner bonding layer and the inner disc.

[0028] In the second and third preferred embodiments, the composite pane comprises, in the specified order: the outer pane, the first outer bonding layer, the thermochromic film, the second outer bonding layer, the aerogel layer, an inner bonding layer and the inner pane.

[0029] In the fourth preferred embodiment, the composite disc comprises, in the specified order: the outer disc, the outer bonding layer with the embedded thermochromic particles, the aerogel layer, an inner bonding layer and the inner disc.

[0030] In the fifth preferred embodiment, the composite disc comprises, in the specified order: the outer disc, the outer bonding layer, the aerogel layer with the thermochromic coating, an inner bonding layer and the inner disc.

[0031] Alternatively, it is conceivable that the aerogel layer is produced directly on the surface of the inner disk facing the intermediate layer, instead of being connected to it via a bonding layer. The production of the aerogel layer on the surface is preferably carried out using a sol-gel process. It then adheres to the surface without the need for a bonding layer.

[0032] In the first preferred embodiment, the composite disc then comprises, in the specified order: the outer disc with the thermochromic coating, the outer bonding layer, the aerogel layer and the inner disc on which the aerogel layer is produced.

[0033] In the second and third preferred embodiments, the composite disc then comprises, in the specified order: the outer disc, the first outer bonding layer, the thermochromic film, the second outer bonding layer, the aerogel layer and the inner disc on which the aerogel layer is produced.

[0034] In the fourth preferred embodiment, the composite disc then comprises, in the specified order: the outer disc, the outer bonding layer with the embedded thermochromic particles, the aerogel layer and the inner disc on which the aerogel layer is produced.

[0035] In the fifth preferred embodiment, the composite disc then comprises, in the specified order: the outer disc, the outer bonding layer, the aerogel layer with the thermochromic coating, and the inner disc on which the aerogel layer is produced.

[0036] 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.

[0037] In particularly preferred embodiments, the laminated glass consists structurally only of the elements specified. The outer pane and / or the inner pane (or the aerogel layer or further layers of the interlayer) may also be equipped with standard coatings or imprints.

[0038] The bonding layers serve to adhesively connect the components of the composite disc between which they are positioned. These bonding layers are preferably composed of one or more thermoplastic layers (SAINT-GOBAIN SEKURIT FRANCE 2024335-WO-PCT). Alternatively, the thermoplastic layers can also be referred to as thermoplastic sheets.

[0039] 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% by weight). In addition to the polymer, the layer may contain other additives, such as plasticizers, UV absorbers, 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.

[0040] 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.

[0041] 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.

[0042] 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 spectral range of the infrared components 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.

[0043] Or, to put it another way: thermochromic materials are known for changing color when a certain transition temperature is exceeded. The present invention utilizes the fact that this color change is also accompanied by a change in transmittance in the infrared range. Thus, the thermochromic layer can be used to reduce the transmittance to the infrared components of solar radiation at high ambient temperatures, thereby reducing heat gain through the laminated glass into the interior.

[0044] 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.

[0045] 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.

[0046] The transition temperature is preferably in the range of 10°C to 100°C, particularly preferably from 15°C to 45°C, and most preferably from 15°C to 25°C.

[0047] The aforementioned transmittance of the thermochromic layer is determined as the integral transmittance in a wavelength range from 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 is plotted against the temperature T, a first plateau is observed below the transition temperature. SAINT-GOBAIN SEKURIT FRANCE 2024335- WO-PCT

[0048] (constant transmittance) 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,

[0049] The value 1 is larger 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.

[0050] 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, I .TRIR, 2). The transition temperature To is then the temperature at which this function value TRIR(TO) occurs.

[0051] The amount of the difference between the first plateau TRIR, 1 and the second plateau TRIR,

[0052] 2 is typically at least 5%, preferably at least 10%, particularly preferably at least 20%. This applies to the thermochromic layer itself.

[0053] 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.

[0054] 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, localized areas can be excluded from the coating to function as so-called communication or data transmission windows. SAINT-GOBAIN SEKURIT FRANCE 2024335-WO-PCT

[0055] 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.

[0056] The thickness of the aerogel layer can be selected according to the requirements of the specific application. Factors particularly important include the thermal conductivity of the aerogel (which in turn depends on the material, density, and porosity), the heat absorption of the composite pane (which in turn depends on the other components of the composite pane, especially the material, thickness, and tint of the outer pane, the inner pane, and the bonding layers), and the desired heat transfer (i.e., the desired TTS value, the total solar energy transmitted, or the specific ll value, the total heat transfer). Preferably, the aerogel layer has a thickness in the range of 0.1 mm to 10 mm, particularly preferably from 0.2 mm to 8 mm, and especially from 0.5 mm to 6 mm, for example, from 1 mm to 4 mm. This achieves good results in typical applications.

[0057] The aerogel layer can optionally have an edge seal, for example in the form of a polymeric band or a polymeric film.

[0058] Contrary to what the name might initially suggest, aerogels are not gels, but highly porous solids. The name derives from the fact that aerogels are typically produced from gels, with the liquid component of the gel being replaced by a gas without the gel structure collapsing, for example, through supercritical drying or freeze-drying. Structurally, aerogels consist of a branching network of particle chains (dendritic structure) with numerous spaces (pores), particularly in the form of open pores. The particle chains have contact points with each other, so the aerogel can be considered a stable, sponge-like network. The particle chains themselves often result from the fusion of, for example, spherical particles. A very high volume fraction of aerogels consists of pores, especially open pores. Therefore, aerogels have a very low density.The aerogel layer according to the invention is therefore lightweight, so that the weight of the laminated glass is not significantly increased even by comparatively thick aerogel layers. Aerogels can also exhibit high optical transparency, which can be particularly advantageous for applications in glazing. Aerogels can be produced, for example, by sol-gel processes.

[0059] Inclusions may be present in the pores, for example, to influence the mechanical, thermal, or optical properties of the aerogel layer. The pores are typically air-filled, apart from any inclusions. The aerogel layer according to the invention can also be referred to as an aerogel layer or as a layer or layer made of or based on an aerogel.

[0060] For the purposes of this invention, porosity is defined as the proportion of the pore volume to the total volume of the aerogel. The aerogel layer according to the invention is preferably formed from, or based on, an aerogel having a porosity of 50% to 99.98%, particularly preferably 80% to 99%, and most preferably 85% to 98%. The porosity can be determined by gas sorption measurement, in particular using carbon dioxide (CO2) as the measuring gas at a temperature of 273 K.

[0061] The pore size of the aerogel is preferably from 1 nm to 50 nm, particularly preferably from 10 nm to 40 nm. This refers specifically to the diameter of the typically approximately spherical pores. The pore size can also be determined using the aforementioned gas sorption measurement.

[0062] The density of the aerogel is preferably 0.16 mg / cm³. 3 up to 500 mg / cm² 3 , particularly preferably of 10 mg / cm² 3up to 300 mg / cm² 3 This refers to the bulk density based on the volume including the pore spaces, whereby the air in the pores is not included in the mass.

[0063] The particles that make up the network of particle chains typically have a size of 1 nm to 10 nm.

[0064] Aerogels can be formed from various materials (material of the particle chains). The aerogel of the aerogel layer according to the invention is preferably made of silicate, from a SAINT-GOBAIN SEKURIT FRANCE 2024335- WO-PCT

[0065] Aerosols can be formed from a polymer, carbon, cellulose, or a metal oxide. In principle, all polymers and metal oxides are suitable. Examples include polyimide for a polymer and aluminum oxide, titanium oxide, zirconium oxide (all white or bluish), iron oxide (red or yellow), chromium oxide (green or blue), and vanadium oxide (olive green) for metal oxides. Strictly speaking, silicate aerosols do not have the chemical composition of a silicate, but rather something like SiO(OH)₂. y (OR) z, where R is an organic residue and the parameters y and z depend on the manufacturing process. They are nevertheless generally referred to as such, and the term silicate is also used accordingly within the scope of the present invention. In English, the term "silica aerogel" (i.e., SiO2 aerogel) is also common. For the aerogel layer according to the invention, silicate aerogels, polymer aerogels, and cellulose aerogels are particularly preferred. These aerogels are well-researched and already commercially available in large numbers.

[0066] The aerogel layer according to the invention can be structurally different and integrated into the vehicle roof window, in particular

[0067] - as a so-called blanket or mat; this refers to a composite material made of an aerogel (especially silicate aerogel) and a material that influences the mechanical properties; said material is in particular a fiber material (for example, glass fibers); blankets are flexible and can be supplied on rolls, for example; such a mat can, for example, be made of an aerogel felt (especially silicate aerogel felt);

[0068] - as a film; films are flexible and can also be supplied, for example, on rolls; they can be made, for example, from or based on a polymer aerogel, which may optionally contain inclusions; an aerogel film can comprise a carrier film (for example, made of PET or polyimide) on which an aerogel layer is arranged;

[0069] - as a rigid layer (“plate”);

[0070] - in the form of granules (with particle sizes, for example, in the millimeter range) or particles (with particle sizes, for example, in the micrometer range).

[0071] The aerogel layer should be transparent to allow visibility through the laminated glass, or translucent to at least allow light to pass through the laminated glass. A single-piece, transparent aerogel layer, for example as a sheet or film, or a translucent granular version is preferred. SAINT-GOBAIN SEKURIT FRANCE 2024335-WO-PCT

[0072] The composite disc can, in principle, also have several aerogel layers. The thermochromic layer should be positioned on the outer surface of all aerogel layers. However, for the sake of a simple structure and low overall thickness, it is preferable for the composite disc to have only one aerogel layer.

[0073] The interior surface of the inner pane, facing away from the intermediate layer, 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 [reference]).(also standard DIN EN 12898:2019-06). This effectively improves thermal comfort in the interior. At high outside temperatures and with strong sunlight, the emissivity-reducing coatings can at least partially reflect the heat radiation emitted from the entire pane towards the interior. 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.

[0074] 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 interior surface of the inner pane.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 to act as barrier layers to regulate oxygen diffusion during the deposition of the coating.

[0075] The emissivity-reducing coating is preferably applied over the entire surface of the inner pane on the interior side, optionally with the exception of a surrounding uncoated edge area.

[0076] The laminated pane is designed as a glazing element and therefore has a transparent viewing area. This viewing area allows a view through the laminated pane. If the glazing is only intended to allow light to enter without requiring a view through it in the strict sense, it is sufficient if the viewing area, which for the sake of simplicity will also be referred to as such in this case within the meaning of the present invention, is translucent instead of transparent. The laminated pane can be entirely transparent or translucent, so that the viewing area encompasses the entire laminated pane. The laminated pane preferably has a light transmission of at least 3% in the viewing area, more preferably at least 5%, and most preferably at least 6%. Light transmission here refers to the total transmission as defined by ECE-R 43, Annex 3, Section 9.1. Established procedures for testing the light transmittance of motor vehicle windows.

[0077] The transparent or translucent viewing area allows a view through the laminated glass or at least the transmission of light. However, the laminated glass can be tinted or colored to, for example, reduce glare for people inside or the transmission of heat radiation.

[0078] The laminated glass can also have an opaque masking area through which no visibility is possible and no light passes. Such a masking area is particularly common in vehicle windows. It is typically formed by an opaque printing layer on at least one of the surfaces of the inner and / or outer pane, for example, on the interior surface of the outer pane. This involves the use of an enamel printing paste containing glass frits and a pigment (SAINT-GOBAIN SEKURIT FRANCE 2024335- WO-PCT).

[0079] (especially black pigment), for example, printed onto the surface using screen printing and then baked on. The masking area typically comprises a circumferential edge region of the laminated glass, which surrounds a central transparent area like a frame. However, the masking area can also include further areas, which are designed, for example, as a type of cross bracing of the frame-like edge region. The laminated glass preferably has a light transmission of at most 1% in the masking area, particularly preferably at most 0.1%, and particularly essentially 0%.

[0080] 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.

[0081] The aerogel layer and the thermochromic layer preferably completely cover the transparent 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 aerogel layer, the thermochromic layer, and, if applicable, the emissivity-reducing coating extend beyond the transparent area into the masking area. They may extend independently of one another to the side edge of the laminated glass or terminate in the masking area, with their edges maintaining a distance from the side edge of the laminated glass.

[0082] It is possible for the aerogel layer to be present across the entire surface of the laminated glass, extending to the side edges of the laminated glass. Alternatively, it is also possible for the aerogel layer to be arranged within a section of a thermoplastic layer, which surrounds it like a frame. In this case, there is no aerogel layer in the edge region of the laminated glass, and therefore no thermal shielding, which may be acceptable. The frame-like thermoplastic layer should have a width of no more than 10 cm, preferably no more than 5 cm. The frame-like area without an aerogel layer is preferably located entirely within the masking area. SAINT-GOBAIN SEKURIT FRANCE 2024335-WO-PCT

[0083] 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.

[0084] 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.

[0085] Laminated glass can be flat, cylindrical, or spherically curved. Spherically curved laminated glass is common in passenger car windows. Flat laminated glass is particularly prevalent in architecture, but also in the automotive sector, for example, as glazing for buses or commercial vehicles (such as agricultural or construction vehicles).

[0086] The outer pane, the inner pane, the bonding layers, and the aerogel layer 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%, and particularly below 20%. This is preferably achieved by a correspondingly tinted outer pane, inner pane, bonding layer, and / or aerogel layer. The strong tint reduces solar radiation, thus preventing the interior from heating up too much and avoiding glare.

[0087] 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 processes (SAINT-GOBAIN SEKURIT FRANCE 2024335-WO-PCT), 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 is typically achieved under the influence of heat, vacuum, and / or pressure.

[0088] 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 land, air, or water transport. The vehicle roof pane can, in principle, be used in any land, air, or water transport.

[0089] Watercraft are used, preferably in motor vehicles or rail vehicles, especially preferably in passenger cars or trucks, particularly in electric vehicles (electric passenger cars).

[0090] SAINT-GOBAIN SEKURIT FRANCE 2024335-WO-PCT

[0091] 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:

[0092] 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 ,

[0093] Fig. 3 shows a cross-section along XX' through a further embodiment of the composite disk according to the invention,

[0094] Fig. 4 shows a cross-section along XX' through a further embodiment of the composite disk according to the invention.

[0095] Figures 1 and 2 each show a detail of an embodiment of the laminated glass according to the invention. The laminated glass is designed as a vehicle roof window. It consists of an outer pane 1 and an inner pane 2, which are bonded together over their entire surface via an intermediate layer 3. 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.

[0096] 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 and the intermediate layer 3, 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.

[0097] An aerogel layer 5 is arranged in the intermediate layer 3. The aerogel layer 5 is connected to the outer disk 1 via an outer bonding layer, which is formed as a single thermoplastic layer 3a (outer thermoplastic layer 3a), and to the inner disk 2 via an inner bonding layer, which is formed as a single thermoplastic layer 3b (inner thermoplastic layer 3b). The thermoplastic layers 3a and 3b are each formed from a PVB film with a thickness of 0.76 mm. The aerogel layer 5, for example, has a thickness of 2 mm. It is formed, for example, from a transparent polymer aerogel. SAINT-GOBAIN SEKURIT FRANCE 2024335-WO-PCT

[0098] A thermochromic layer 4 is applied as a coating to the inner surface of the outer pane 1, facing the inner pane 2 and the intermediate layer 3. The thermochromic layer 4 completely covers the viewing area D and extends from there into the masking area M. In the masking area M, the thermochromic layer 4 can be positioned below or above the masking print 8.

[0099] The thermochromic layer 4 changes its transmittance to infrared 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 aerogel layer 5 is thermally insulating and reduces heat conduction through the laminated glass. Overall, heat transmission 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 4 exhibits a higher transmittance to infrared radiation, which is advantageous with regard to preventing the interior from heating up due to solar radiation. The heat-insulating aerogel layer 5 reduces heat loss from the interior through conduction.This also improves thermal comfort in the interior, which requires less heating. The reduced need for cooling and heating systems further saves energy. The aerogel layer 5 also improves the acoustic insulation of the laminated glass.

[0100] An additional emissivity-reducing coating 6 is applied to the interior surface of the inner pane 2, the side facing away from the outer pane 1 and the intermediate layer 3. The emissivity-reducing coating 6 covers the entire surface. At high outside temperatures, the emissivity-reducing coating 6 reflects the thermal radiation emitted by the heated laminated pane into the interior, and at low outside temperatures, it reflects the thermal radiation emitted from the interior. The emissivity-reducing coating 6 thus further reduces heat transmission through the laminated pane due to IR and thermal radiation.

[0101] The composite disc comprises, in the following order: SAINT-GOBAIN SEKURIT FRANCE 2024335-WO-PCT

[0102] - the outer pane 1 with the thermochromic layer 4 and the cover print 8,

[0103] - the outer thermoplastic layer 3a, which acts as an outer bonding layer,

[0104] - the aerogel layer 5,

[0105] - the inner thermoplastic layer 3b, which acts as an inner bonding layer, and

[0106] - the inner pane 2 with the emissivity-reducing coating 6.

[0107] Figure 3 shows a further embodiment of the composite disc according to the invention. The outer disc 1 with the cover print 8, the aerogel layer 5, the inner bonding layer (inner thermoplastic layer 3b) and the inner disc 2 with the optional emissivity-reducing coating 6 are designed in the same way as in the embodiment of Figures 1 and 2.

[0108] The composite disc differs from the previous design by the integration of the thermochromic layer 4. This layer is designed as a thermochromic film. The thermochromic film is connected to the outer disc 1 via a first outer bonding layer and to the aerogel layer 5 via a second outer bonding layer. The outer bonding layers are each designed as individual thermoplastic layers 3a and 3c (first outer thermoplastic layer 3a, second outer thermoplastic layer 3c). The thermoplastic layers 3a and 3c are each made of a PVB film with a thickness of 0.38 mm.

[0109] 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.

[0110] The composite disc comprises, in the following order:

[0111] - the outer pane 1 with the cover pressure 8,

[0112] - the first outer thermoplastic layer 3a, which acts as the first outer bonding layer,

[0113] - the thermochromic film as thermochromic layer 4,

[0114] - the second outer thermoplastic layer 3c, which acts as the second outer bonding layer,

[0115] - the aerogel layer 5, SAINT-GOBAIN SEKURIT FRANCE 2024335-WO-PCT, the inner thermoplastic layer 3b, which acts as an inner bonding layer, and the inner disc 2 with the emissivity-reducing coating 6.

[0116] Figure 4 shows a further embodiment of the composite disc according to the invention. The outer disc 1 with the cover print 8, the aerogel layer 5, the inner bonding layer (inner thermoplastic layer 3b) and the inner disc 2 with the optional emissivity-reducing coating 6 are designed in the same way as in the embodiments of Figures 1 to 3.

[0117] The composite disc differs from previous designs by the integration of the thermochromic layer 4. The aerogel layer 5 is connected to the outer disc 1 via an outer bonding layer, which is designed as a single thermoplastic layer 3a (outer thermoplastic layer 3a). The outer thermoplastic layer 3a is made of a PVB film with a thickness of 0.76 mm. Thermochromic particles are added to this outer thermoplastic layer 3a, so that the outer thermoplastic layer 3a simultaneously functions as the thermochromic layer 4.

[0118] The composite disc comprises, in the following order:

[0119] - the outer pane 1 with the cover pressure 8,

[0120] - the outer thermoplastic layer 3a with the thermochromic inclusions, which acts as an outer bonding layer,

[0121] - the aerogel layer 5,

[0122] - the inner thermoplastic layer 3b, which acts as an inner bonding layer, and

[0123] - the inner pane 2 with the emissivity-reducing coating 6.

[0124] SAINT-GOBAIN SEKURIT FRANCE 2024335-WO-PCT

[0125] Reference symbol list:

[0126] (1) Outer pane

[0127] (2) Inner disc (3) Intermediate layer

[0128] (3a) (first) outer thermoplastic layer

[0129] (3b) inner thermoplastic layer

[0130] (3c) (second) outer thermoplastic layer

[0131] (4) thermochromic layer (5) aerogel layer

[0132] (6) emissivity-reducing coating

[0133] (8) Cover printing

[0134] (D) Viewing area of ​​the laminated pane (M) Masking area of ​​the laminated pane

[0135] X - X' Intersection line

Claims

25 SAINT-GOBAIN SEKURIT FRANCE 2024335-WO-PCT Patent claims 1. Composite disc comprising an outer disc (1) and an inner disc (2) connected to each other via an intermediate layer (3), wherein the intermediate layer (3) contains an aerogel layer (5) and wherein a thermochromic layer (4) is arranged between the aerogel layer (5) and the outer disc (1).

2. Composite disc according to claim 1, wherein the thermochromic layer (4) is formed as a thermochromic coating on the surface of the outer disc (1) facing the intermediate layer (3), and wherein the aerogel layer (5) is connected to the outer disc (1) via an outer bonding layer, and wherein the aerogel layer (5) is connected to the inner disc (2) via an inner bonding layer or is produced directly on the surface of the inner disc (2) facing the intermediate layer (3).

3. Composite disc according to claim 1, wherein the thermochromic layer (4) 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 via a first outer bonding layer and to the aerogel layer (5) via a second outer bonding layer, and wherein the aerogel layer (5) is connected to the inner disc (2) via an inner bonding layer or is produced directly on the surface of the inner disc (2) facing the intermediate layer (3).

4. Composite disc according to claim 1, wherein the thermochromic layer (4) 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 via a first outer bonding layer and to the aerogel layer (5) via a second outer bonding layer. SAINT-GOBAIN SEKURIT FRANCE 2024335-WO-PCT and wherein the aerogel layer (5) is connected to the inner disk (2) via an inner bonding layer or is produced directly on the surface of the inner disk (2) facing the intermediate layer (3).

5. Composite disc according to claim 1, wherein the aerogel layer (5) is connected to the outer disc (1) via an outer bonding layer and wherein thermochromic particles are embedded in the outer bonding layer, such that the outer bonding layer forms the thermochromic layer (4), and wherein the aerogel layer (5) is connected to the inner disc (2) via an inner bonding layer or is produced directly on the surface of the inner disc (2) facing the intermediate layer (3).

6. Composite disc according to one of claims 2 to 5, wherein the bonding layers are formed as thermoplastic layers (3a, 3b, 3c), 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).

7. Composite disc according to one of claims 1 to 6, wherein the thermochromic layer (4) transitions from a state of higher transmission of IR radiation to a state of lower transmission of IR radiation when a transition temperature is exceeded.

8. Composite disc according to claim 7, wherein the transition temperature is from 10°C to 100°C, preferably from 15°C to 45°C, particularly preferably from 15°C to 25°C.

9. Composite disc according to any one of claims 1 to 8, wherein the aerogel layer (5) has a thickness of 0.1 mm to 10 mm, preferably 0.5 mm to 6 mm.

10. Composite disc according to one of claims 1 to 9, wherein the aerogel layer (5) is based on a silicate aerogel, polymer aerogel or cellulose aerogel.

11. Composite disc according to one of claims 1 to 10, wherein the aerogel layer (5) is based on an aerogel having a porosity of 50% to 99.98%, preferably 80% to 99%, as determined by gas sorption measurement. SAINT-GOBAIN SEKURIT FRANCE 2024335-WO-PCT 12. Laminated glass pane according to any one of claims 1 to 11, wherein the surface of the inner pane (2) facing away from the intermediate layer (3) is provided with an emissivity-reducing coating (6).

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. Composite disc according to 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 aerogel layer (5), the thermochromic layer (4) and optionally the emissivity-reducing coating (6) 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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