Vehicle side window comprising an aerogel layer

Abstract

The present invention relates to a vehicle side window (S), comprising an outer pane (1) and an inner pane (2), which are connected to each other by means of a frame-like spacer (4) such that a hollow space delimited by the outer pane (1), the inner pane (2) and the spacer (4) is formed, an aerogel layer (3) being located in the hollow space.

Description

[0001] Vehicle side window with an aerogel layer

[0002] The invention relates to a vehicle side window equipped with an aerogel layer and to the use thereof.

[0003] The energy input through the glazing is a problem for vehicle glazing. The total solar energy radiated is made up of the direct energy radiated and the indirect energy radiated as thermal radiation after the pane components have heated up. This is typically characterized as the TTS value. If the vehicle interior heats up too much, it must be countered with air conditioning, which is not in the spirit of energy-saving operation. At low outside temperatures, heat is lost through the glazing, meaning the interior must be heated, which is also energy-intensive. The high energy consumption is particularly critical for electric vehicles because it leads to a shortened running time until the next necessary battery recharge. In addition, the waste heat from a combustion engine cannot be used for heating, so the heating must also be operated electrically.Vehicle manufacturers therefore strive to minimize energy input and heat loss through the glazing as much as possible and thereby improve thermal comfort in the vehicle interior.

[0004] Vehicle windows are often designed as composite panes, comprising an outer pane and an inner pane laminated together via a thermoplastic interlayer. The thermal comfort of such composite panes can be improved by IR-reflective coatings. For example, solar control coatings are known, which comprise IR-reflective silver layers to reflect the IR components of solar radiation. Emissivity-reducing coatings (low-E coatings) are also known, with reflective properties in the mid-IR range, which reflect the thermal radiation emanating from the heated pane in summer and the thermal radiation emanating from the interior in winter.For example, reference is made to WO2019110172A1, which discloses a composite pane with a solar control coating (for example, on the interior surface of the outer pane) and an emissivity-reducing coating (on the interior surface of the inner pane). Aerogels are highly porous solids known for their very low thermal conductivity and heat-insulating properties. WO2012154602A1 discloses an insulating glazing unit with an aerogel layer. US2010146880A1 discloses a building roof pane consisting of two glass panes and an aerogel layer between them.

[0005] EP3381881A1 discloses a vehicle window consisting of two glass panes and a thermally insulating layer between them, which can be formed as an aerogel layer. However, moisture can penetrate through the side edge of this composite pane, which can damage and / or contaminate the typically moisture-sensitive aerogel layer. This is particularly true for side windows that can be raised and lowered, where, in the open (lowered) state, part of the side edge (upper edge) is exposed and not protected by the vehicle body.

[0006] The present invention is based on the object of providing an improved vehicle side window which reduces the thermal energy input into the vehicle interior in summer and the heat loss out of the vehicle interior in winter.

[0007] The object is achieved according to the invention by a vehicle side window according to independent claim 1. Advantageous embodiments emerge from the subclaims.

[0008] The vehicle side window according to the invention comprises an outer pane and an inner pane, which are connected to each other via a frame-like spacer. This forms a cavity defined by the outer pane, the inner pane, and the spacer. According to the invention, an aerogel layer is arranged in this cavity.

[0009] The aerogel layer acts as a heat-insulating layer, reducing heat transfer through the side window, particularly heat conduction through the side window. As a result, the vehicle interior heats up less at high outside temperatures (in summer) and cools down less at low outside temperatures (in winter). The aerogel layer therefore provides the side window with improved thermal insulation properties. The aerogel layer also has acoustically insulating properties, which is advantageous for shielding from disruptive external noise. The aerogel layer is very lightweight, so the overall weight of the side window is also comparatively low. The frame-like spacer prevents moisture and dirt from penetrating the cavity, thereby protecting the aerogel layer from degradation. These are major advantages of the present invention.

[0010] The side window according to the invention is intended to separate a vehicle interior from the outside environment in a side window opening of a vehicle. In the sense of the invention, the inner pane refers to the pane facing the interior. The outer pane refers to the pane facing the outside environment. The outer pane and the inner pane each have an outside surface and an inside surface and a circumferential side edge surface running between them. In the sense of the invention, the outside surface refers to the main surface which is intended to face the outside environment in the installed position. In the sense of the invention, the inside surface refers to the main surface which is intended to face the interior in the installed position.The interior surface of the outer pane and the exterior surface of the inner pane face each other and are connected to each other.

[0011] The side window according to the invention is preferably an openable, in particular a raising and lowering side window. Such a side window has a section adjacent to the lower edge (facing downward in the installed position), which is always arranged within the vehicle body (typically a vehicle door), and which is adjoined by a section that projects into the window opening and closes it (when closed). The side window can be lowered completely or partially into the vehicle body (typically a vehicle door), thereby opening the side window.For this purpose, the section of the side window permanently located within the vehicle body is connected to a mechanism for raising and lowering the side window, which mechanism is arranged within the vehicle body (typically within a vehicle door) and is driven electrically (typically triggered by a vehicle occupant pressing a push button) or mechanically (typically by a vehicle occupant operating a crank). In one embodiment, the aerogel layer is connected to at least the outer pane or the inner pane via a connecting layer. Preferably, the aerogel layer is connected to the outer pane and the inner pane via a connecting layer. In the latter case, the side window is designed like a composite pane, which is particularly advantageous for its stability and fracture resistance.

[0012] The said at least one connecting layer serves to adhesively bond the aerogel layer to the outer pane and / or the inner pane. Each connecting layer is preferably formed as a thermoplastic layer. The thermoplastic layer can alternatively also be referred to as a thermoplastic layer.

[0013] The thermoplastic layer(s) is / are preferably based on polyvinyl butyral (PVB), ethylene-vinyl acetate (EVA), or polyurethane (PU), or on mixtures or copolymers or derivatives thereof, particularly preferably based on PVB. This means that the layer predominantly contains the said polymer (a proportion greater than 50% by weight). In addition to the polymer, the layer may contain further additives, for example, plasticizers, UV absorbers, or stabilizers. Each thermoplastic layer is preferably formed from at least one thermoplastic film. The thickness of each film is preferably between 0.2 mm and 1 mm. For example, PVB films with standard thicknesses of 0.38 mm or 0.76 mm can be used.

[0014] Each connecting layer can alternatively be formed, for example, as an adhesive layer. So-called optically clear adhesives (OCA) are preferred. OCAs are known as such to those skilled in the art. They are characterized in particular by their high optical quality. They are particularly 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 their high light transmission and the fact that low-distortion visibility is possible. The optically clear adhesive is preferably a 2-component polyurethane adhesive, a 1-component acrylate adhesive, a 1-component silicone adhesive, or a 1-component acrylate hybrid adhesive.The OCA layer is preferably produced from a highly viscous OCA, so that it can be provided in a film-like manner as a prefabricated layer (OCA film). The thickness of such an OCA film is preferably from 0.1 mm to 1.8 mm, particularly preferably from 0.3 mm to 0.8 mm. A combination is also conceivable, with the aerogel layer being bonded to one of the panes via a thermoplastic layer and to the other pane via an OCA layer.

[0015] In this embodiment, the aerogel layer is preferably provided as a prefabricated block or plate and then connected to the at least one surface of the outer pane or inner pane via the at least one connecting layer. To facilitate the production of the aerogel layer, it can be produced, for example, on a carrier film. The carrier film can then be removed or remain permanently in the side pane. For example, it is possible to connect the surface facing away from the carrier film and / or the carrier film itself to the pane surface facing it via the connecting layer. From a process engineering perspective, it is particularly advantageous if the carrier film is a connecting layer, for example a thermoplastic film (such as PVB film) or an OCA film.The aerogel layer can then be bonded to one pane surface via the carrier film and optionally to the opposite pane surface via a further bonding layer.

[0016] In a further embodiment, the aerogel layer is produced directly on the surface of the outer pane or the inner pane (or any coating applied thereto) that faces the cavity. The aerogel layer is preferably produced or manufactured on the surface using a sol-gel process. It then adheres to said surface without the need for a bonding layer.

[0017] A combination is also conceivable, whereby the aerogel layer is produced on one of the panes and is connected to the other pane via a connecting layer (in particular a thermoplastic layer or OCA layer).

[0018] In both embodiments, the spacer is preferably connected to the outer pane and the inner pane via a connecting layer, for example, a thermoplastic layer or an OCA layer. In the embodiment in which the aerogel layer is connected to the outer pane and the inner pane via connecting layers, the spacer is preferably connected to the outer pane and the inner pane using the same connecting layers. In principle, it is also conceivable for the material of the spacer itself to have adhesive properties with respect to the panes and to be directly bonded to them, for example, by heating, without the use of a connecting layer.

[0019] The outer pane and the inner pane are independently preferred as

[0020] - thermally toughened glass pane,

[0021] - non-tempered glass pane,

[0022] - chemically toughened glass pane or

[0023] - Plastic disc formed.

[0024] The glass panes can be made of soda-lime glass, quartz glass, borosilicate glass or aluminosilicate glass, for example.

[0025] Thermally toughened and non-toughened glass panes are preferably made of soda-lime glass, as is common for window panes. Their thickness is preferably from 0.5 mm to 5 mm, more preferably from 1 mm to 4 mm, most preferably from 1.5 mm to 4 mm, or even from 1.5 mm to 3 mm.

[0026] Chemically toughened glass panes preferably have a thickness of 0.3 mm to 1 mm, particularly preferably 0.5 mm to 0.7 mm. They are preferably made of aluminosilicate glass, which is particularly suitable for chemical toughening.

[0027] Plastic panes are preferably made of rigid, clear plastics, such as polycarbonate (PC), polymethyl methacrylate (PMMA), or polyethylene terephthalate (PET). Their thickness is preferably from 0.5 mm to 5 mm, particularly preferably from 1 mm to 4 mm, most preferably from 1.5 mm to 4 mm, or even from 1.5 mm to 3 mm.

[0028] The following combinations of outer pane and inner pane are particularly preferred:

[0029] 1. Outer pane: thermally toughened glass pane, inner pane: thermally toughened glass pane

[0030] 2. Outer pane: non-tempered glass pane, inner pane: non-tempered glass pane 3. Outer pane: chemically toughened glass pane, inner pane: chemically toughened glass pane

[0031] 4. Outer pane: thermally toughened glass pane, inner pane: chemically toughened glass pane

[0032] 5. Outer pane: thermally toughened glass, inner pane: plastic pane

[0033] Thermally or chemically toughened glass panes exhibit increased fracture resistance. Thermally toughened glass panes shatter into a large number of small, non-sharp-edged shards when broken, posing only a minimal risk of injury. Non-toughened glass panes, on the other hand, shatter into large, sharp-edged shards when broken. If the aerogel layer is bonded to the outer and inner panes via bonding layers, the glass shards are held in place by the bonding layers and pose no risk of injury. Therefore, non-toughened glass panes can also be used without any problems in this variant.If the aerogel layer is not bonded to the panes via bonding layers, but is created directly on a pane, and a non-tempered glass pane (inner or outer pane) or two non-tempered glass panes (inner and outer pane) are to be used, each non-tempered glass pane is preferably provided with a splinter-binding film, which fixes the shards in the event of glass breakage and thus reduces the risk of injury. Even if the aerogel layer is only bonded to one of the panes via a bonding layer and non-tempered glass is to be used for the other pane, this non-tempered glass pane is preferably provided with a splinter-binding film.

[0034] The spacer is designed to prevent moisture from penetrating the cavity containing the aerogel layer. The spacer thus seals the cavity watertight.

[0035] The spacer is preferably made of a polymer, in particular a transparent polymer. For example, the spacer can be made of transparent polycarbonate, PMMA, PET, polyvinyl chloride (PVC), or polystyrene. The spacer can be provided with a waterproof film. It is also possible to have a sealing compound on the side of the spacer facing away from the cavity to improve the watertightness of the cavity.

[0036] The spacer has a frame-like, circumferential shape. The length of the spacer is understood to be the dimension in the frame-like, circumferential extension direction of the spacer. The length of the spacer depends on the base area of ​​the side window or the area of ​​the side window enclosed by the spacer. The width of the spacer is understood to be the dimension perpendicular to the length dimension, determined in a plane parallel to the surfaces of the outer window and inner window. The width of the spacer is preferably between 3 mm and 10 mm. This achieves a stable connection between the outer window and inner window and a watertight seal of the cavity without the spacer taking up too much space, which would then no longer be available for the aerogel layer. The height of the spacer is understood to be the dimension between the outer window and inner window.The height of the spacer, along with the thickness of the bonding layers used to attach it to the pane surfaces, determines the distance between the outer and inner panes and thus the thickness of the cavity. It can be selected according to the requirements of the specific application.

[0037] The spacer can be solid or hollow, having an inner cavity surrounded by walls made of the spacer material.

[0038] A transparent spacer is ideal because it is not noticeable in the typically completely transparent side window. In principle, however, non-transparent spacers can also be used. For example, spacers made of metal or wood can be used, whereby the required watertightness can be ensured if necessary by a polymer or metallic film. Non-transparent spacers can, for example, serve as design elements of the side window or be concealed by opaque cover prints on the outer and inner panes. The thickness of the aerogel layer can be selected according to the requirements of the specific application. The aerogel layer preferably has a thickness in the range of 0.1 mm to 10 mm, more preferably from 0.2 mm to 8 mm, most preferably from 0.5 mm to 6 mm, in particular from 1 mm to 4 mm. This achieves good results in typical applications.

[0039] Ideally, the aerogel layer covers the entire area of ​​the side window enclosed by the spacer. Then, the aerogel layer is in direct contact with the spacer. This is particularly preferred because it prevents the formation of a thermal bridge in areas without an aerogel layer. However, a gap may be present between the aerogel layer and the spacer, particularly for production-related reasons. The gap between the aerogel layer and the spacer should be no more than 2 mm, preferably no more than 1 mm, and particularly preferably no more than 0.5 mm.

[0040] If the aerogel layer is attached to only one of the surfaces of the outer or inner pane (via a bonding layer or directly applied to the respective surface), the aerogel layer can extend to the other pane surface and be in direct contact with it. The aerogel layer then fills the cavity across its entire thickness. This is particularly preferred with regard to optimal thermal insulation. Alternatively, however, there may be a gap between the aerogel layer and the surface of the pane to which it is not attached. The gap between the aerogel layer and said surface is preferably at most 1 mm, more preferably at most 0.5 mm, and most preferably at most 0.2 mm.

[0041] The distance between the outer and inner panes is the sum of the height of the spacer and the thickness of the bonding layers between the spacer and the pane surfaces. The distance must be at least equal to the thickness of the aerogel layer. Ideally, the distance is equal to the thickness of the aerogel layer. However, the distance can be slightly larger, preferably by no more than 1 mm, more preferably by no more than 0.5 mm, and most preferably by no more than 0.2 mm.

[0042] Contrary to what the name initially suggests, aerogels are not gels, but highly porous solids. The name derives from the fact that aerogels are typically made from gels, whereby the liquid component of the gel is replaced by a gas without collapsing the gel structure, for example through supercritical drying or freeze-drying. Structurally, aerogels consist of a branching of particle chains (dendritic structure) with very many interstices (pores), particularly in the form of open pores. The particle chains have contact points with one another, so that the aerogel can be thought of as 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, particularly 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 side window is not significantly increased even by comparatively thick aerogel layers. Aerogels can also exhibit high optical transparency, which is particularly advantageous for glazing applications. Aerogels can be produced, for example, using sol-gel processes.

[0043] Intercalations may be present in the pores, for example, to influence the mechanical, thermal, or optical properties of the aerogel layer. The pores are typically filled with air, except for any intercalations. The aerogel layer according to the invention can also be referred to as an aerogel layer or as a layer made of an aerogel or based on an aerogel.

[0044] For the purposes of the invention, porosity refers to 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 using nitrogen as the measurement gas, in particular using carbon dioxide (CO2) as the measurement gas at a temperature of 273 K.

[0045] The pore size of the aerogel is preferably between 1 nm and 50 nm, particularly preferably between 10 nm and 40 nm. This refers in particular to the diameter of the typically approximately spherical pores. The pore size can also be determined using the aforementioned gas sorption measurement.

[0046] The density of the aerogel is preferably 0.16 mg / cm 3 up to 500 mg / cm 3, particularly preferably 10 mg / cm 3 up to 300 mg / cm 3 This refers to the bulk density based on the volume including the pore spaces, with the air in the pores not included in the mass. The particles that make up the network of particle chains typically have a size of 1 nm to 10 nm.

[0047] 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, a polymer, carbon, cellulose, or a metal oxide. In principle, all polymers and metal oxides are suitable. Examples are polyimide for a polymer and aluminum oxide, titanium oxide, and zirconium oxide for metal oxides. Strictly speaking, silicate aerosols do not have the chemical composition of a silicate, but rather, for example, SiO(OH). y(OR)z, where R is an organic residue and the parameters y and z depend on the manufacturing process. Nevertheless, they are generally referred to as such, and the term silicate is used accordingly in the context of the present invention. In English, the term "silica aerogel" is also commonly used (i.e., SiO2 aerogel). Silicate aerogels, polymer aerogels, and cellulose aerogels are particularly preferred for the aerogel layer according to the invention. These aerogels are well researched and already commercially available in large numbers.

[0048] The aerogel layer is preferably transparent so that it does not restrict visibility through the side window. The aerogel layer preferably has a light transmission of more than 70%, particularly preferably more than 80%. The aerogel layer is preferably colorless.

[0049] The outer pane, the inner pane and any connecting layers can be provided with standard coatings or prints.

[0050] In an advantageous embodiment, an IR-reflecting coating is applied to the interior-facing surface of the outer pane facing the aerogel layer. This coating can also be referred to as a solar control coating.

[0051] In an advantageous embodiment, an IR-reflective coating is applied to the outer surface of the inner pane facing the aerogel layer. This coating can also be referred to as an emissivity-reducing coating (LowE coating). The sun protection coating and the emissivity-reducing coating are preferably thin-film stacks, i.e., sequences of thin individual layers. The sun protection coating and the emissivity-reducing coating each comprise at least one IR-reflective layer. The IR-reflective layer is preferably a metallic layer, particularly preferably based on silver. The IR-reflective layer preferably contains at least 90 wt.% silver, particularly preferably at least 99 wt.% silver, very particularly preferably at least 99.9 wt.% silver. The silver layer can contain dopants, for example palladium, gold, copper, or aluminum.The thickness of the silver layer is usually from 5 nm to 20 nm.

[0052] In addition to the metallic layer, dielectric layers or layer sequences are typically present. Dielectric layers or layer sequences are also referred to below as dielectric layer modules. The solar control coating and the emissivity-reducing coating each comprise n metallic layers and (n+1) dielectric layer modules. The dielectric layer modules and the metallic layers are arranged alternately, so that each metallic layer is arranged between two dielectric layer modules, and one layer module is arranged between adjacent metallic layers. The number n is a natural number greater than or equal to 1 (n > 1).

[0053] In a preferred embodiment, the sun protection coating and the emissivity-reducing coating each have at least two metallic layers (n > 2), for example exactly two metallic layers (n = 2), or even at least three metallic layers (n > 3), for example exactly three metallic layers (n = 3). A plurality of metallic layers can improve the IR-reflecting effect without reducing the light transmission too much, because the individual metallic layers can be made thinner. On the other hand, the number of metallic layers should not be too large in order to keep production costs low. The IR-reflecting metallic layers preferably have thicknesses of 5 nm to 20 nm, independently of one another.

[0054] The layer modules can be formed independently of one another, as individual dielectric layers or as dielectric layer sequences (i.e., a plurality of consecutive dielectric layers). Common dielectric layers of such a thin-film stack include, for example:

[0055] Anti-reflective coatings which reduce the reflection of visible light and thus increase the transparency of the coated pane, for example based on silicon nitride (SisN^, silicon-metal mixed nitrides such as silicon zirconium nitride (SiZrN), titanium oxide (TiCh), aluminium nitride (AIN) or tin oxide (ZnO), with layer thicknesses of, for example, 10 nm to 100 nm;

[0056] - Adaptation layers which improve the crystallinity of the electrically conductive layer, for example based on zinc oxide (ZnO), with layer thicknesses of, for example, 3 nm to 20 nm;

[0057] Smoothing layers which improve the surface structure for the overlying layers, for example based on a non-crystalline oxide of tin, silicon, titanium, zirconium, hafnium, zinc, gallium and / or indium, in particular based on tin-zinc mixed oxide (ZnSnO), with layer thicknesses of, for example, 3 nm to 20 nm.

[0058] The solar control coating and the emissivity-reducing coating can each optionally include blocker layers that protect the metallic layers from degradation. Blocker layers are typically very thin metal-containing layers based on niobium, titanium, nickel, chromium, zirconium, or alloys thereof, with layer thicknesses of, for example, 0.1 nm to 0.5 nm.

[0059] If a bonding layer is present between the outer pane and the aerogel layer, the solar control coating can also be embedded in this bonding layer instead of being applied to the interior surface of the outer pane, for example, applied to a carrier film (preferably PET-based) sandwiched between two thermoplastic layers. If a bonding layer is present between the inner pane and the aerogel layer, the emissivity-reducing coating can also be embedded in this bonding layer instead of being applied to the exterior surface of the inner pane, for example, applied to a carrier film (preferably PET-based) sandwiched between two thermoplastic layers.

[0060] The side pane can in principle also have an emissivity-reducing coating on the interior-side surface of the inner pane facing away from the aerogel layer. Such an emissivity-reducing coating is typically a transparent stack of thin films. The emissivity-reducing coating preferably has at least one, particularly preferably precisely one, electrically conductive layer that provides the IR-reflecting 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 includes dielectric layers (e.g., based on silicon oxide or nitride), which serve primarily to optimize the optical properties (e.g., light transmission) or as barrier layers to regulate oxygen diffusion during coating deposition.

[0061] Emissivity-reducing coatings of this type with TCO layers are particularly common for conventional laminated glazing, where the inner pane is heated due to thermal conduction. Since the heated inner pane radiates heat toward the interior, it is necessary for such laminated glazing to apply the emissivity-reducing coating to the interior side of the inner pane, i.e., on the exposed interior surface of the inner pane. In the side pane according to the invention, heat conduction is effectively prevented by the aerogel layer, so it is not absolutely necessary to apply the emissivity-reducing coating to the interior surface of the inner pane.The previously described emissivity-reducing coating with at least one metallic layer, in particular a silver layer, on the outer surface of the inner pane is therefore preferred over an emissivity-reducing coating with a TCO layer on the interior surface of the inner pane. Metallic layers achieve their IR-reflecting effect with thinner layers and are more cost-effective to deposit than TCO layers. Furthermore, a coating on the exposed interior surface of a side pane that can be raised and lowered would be subject to significant mechanical stress, for example, through contact with the sealing lips of the side window, which rub against the coating when the side pane is raised and lowered. Emissivity is the measure that indicates how much thermal radiation the pane emits into an interior in its installed position compared to an ideal thermal radiator (a black body).Emissivity-reducing coatings prevent heat from entering the interior (IR components of solar radiation and, in particular, the thermal radiation from the pane itself) and from escaping it. They exhibit reflective properties against infrared radiation, particularly against thermal radiation in the spectral range of 5 pm - 50 pm (see also standard DIN EN 12898:2019-06). This effectively improves thermal comfort in the interior. At high outside temperatures and in sunlight, the emissivity-reducing coatings can at least partially reflect the thermal radiation emitted by the entire pane toward the interior. At low outside temperatures, they can reflect the thermal radiation emitted from the interior, thus reducing the effect of the cold pane as a heat sink.The emissivity-reducing coating further increases thermal comfort in the interior.

[0062] For the thermal insulation effect of the side window and the thermal comfort in the interior, it is particularly advantageous if the side window has both the previously described sun protection coating on the interior-facing surface of the outer pane and the previously described emissivity-reducing coating on the exterior surface of the inner pane. This configuration is therefore particularly preferred.

[0063] The IR-reflective coatings preferably do not extend beyond the spacer. Instead, a surrounding area of ​​the spacer facing the outside environment is arranged on a coating-free edge area of ​​the outer pane and the inner pane. The coatings then have no contact with the surrounding atmosphere and are protected from corrosion and damage in the cavity.

[0064] In one embodiment of the invention, the outer pane and the inner pane are essentially congruent and the spacer runs circumferentially in an edge region of both the outer pane and the inner pane. In this embodiment, the side pane is formed essentially over its entire surface by the inventive composite of outer pane, inner pane and aerogel layer. In an alternative embodiment of the invention, a connecting section of the outer pane provided for connection to a vehicle body projects beyond the inner pane. The outer pane is therefore larger than the inner pane and the side pane is formed in only one region by the inventive composite of outer pane, inner pane and aerogel layer. This region is referred to as the window region within the meaning of the invention.It is intended to completely cover the vehicle's window opening when closed (from where it extends into the vehicle body). The spacer runs circumferentially in an edge region of the window area and the inner pane. The side window has a further region formed only by the outer pane and intended to connect the side window to the vehicle body, in particular the mechanism located therein for raising and lowering the side window. This region is referred to as the connection region in the sense of the invention. In the installed position, it is always arranged within the vehicle body, both in the open and closed state of the window, and is therefore never visible.

[0065] In the (essentially vertical) installed position of the side window, the connection area is preferably arranged below the window area, thus being at a short distance from the ground. The outer pane and the inner pane are preferably arranged essentially flush at the upper edge of the side window (facing upwards in the installed position) as well as at the front and rear edges (facing forwards and backwards in the installed position relative to the direction of travel). The connection section includes the lower edge of the side window (facing downwards in the installed position), which is identical to the lower edge of the outer pane.

[0066] In this case, only the outer pane needs to be connected to the vehicle body, which has the advantage that conventional connection mechanisms can be used, such as those used for side windows made of single panes of glass.

[0067] Conversely, it is also possible for the connection section to be formed by a portion of the inner pane. In this case, the connection section of the inner pane intended for connection to the vehicle body extends beyond the outer pane. The above statements apply accordingly. Connecting conventional side windows to the raising and lowering mechanism can be achieved in two different ways: In a first variant, the side pane has openings (holes) near the lower edge, into which the mechanism can engage, for example, using a clamping or screw element.In a second variant, a substantially Y-shaped retaining element is provided, with two parallel contact sections, each of which is attached, in particular glued, to one of the external surfaces of the side window. A fastening section extending downward from the contact sections, aligned with the side window, is connected to the raising and lowering mechanism. For this purpose, the fastening section typically also has openings into which a clamping or writing element can be inserted.

[0068] Both variants are also applicable within the scope of the present invention, both in the embodiment with the congruent panes, in which the entire side pane is formed by the composite according to the invention of outer pane, inner pane and aerogel layer, and in the embodiment with the connecting section of the outer pane projecting beyond the inner pane (or vice versa).

[0069] In a first variant of the invention, the side window therefore has at least one lead-through, preferably at least two lead-throughs, in particular exactly two lead-throughs. The lead-throughs are preferably arranged near the lower edge, i.e. are at a shorter distance from the lower edge than from all other edges. The lead-throughs are provided for connecting the side window to the raising and lowering mechanism in the vehicle body and are arranged in a section of the side window adjacent to the lower edge, which section is intended to be always located within the vehicle body and not visible, even when the side window is closed. For connection to the raising and lowering mechanism, a clamping element is preferably clamped into the lead-through or a screw element is screwed into the lead-through. The lead-through is a through hole through the entire side window between its external surfaces.If the side pane is formed entirely from the composite according to the invention comprising the outer pane, aerogel layer, and inner pane, the feedthrough extends through the outer pane, the aerogel layer, and the inner pane. If the side pane has a connecting section that extends beyond the composite according to the invention and is formed only by the outer pane or only by the inner pane, the feedthrough extends only through said outer pane or inner pane, respectively.

[0070] In a second variant of the invention, the side window does not have any such passages. Instead, at least one holding element, preferably at least two holding elements, in particular exactly two holding elements, is attached to the lower edge of the side window. The holding elements are provided for connecting the side window to the raising and lowering mechanism in the vehicle body. Each holding element has at least one contact section which is attached to an external surface of the side window in an area adjacent to the lower edge, in particular via an adhesive layer. Each holding element also has a fastening section adjoining the contact section, which is arranged outside the surface of the side window and serves to connect to the raising and lowering mechanism. This fastening section is preferably provided with a passage.For connection to the raising and lowering mechanism, a clamping element is preferably clamped into the feedthrough or a screw element is screwed into the feedthrough. Typical holding elements, which are also preferred within the scope of the present invention, are Y-shaped and have two parallel contact sections, each contact section being fastened (in particular glued) to one of the external surfaces of the side pane, and a fastening section adjoining the contact sections. If the side pane is formed over its entire surface from the inventive composite of outer pane, aerogel layer, and inner pane, the said external surfaces to which the contact sections are fastened are the surfaces of the outer pane and inner pane facing away from the aerogel layer, i.e. the outside surface of the outer pane and the inside surface of the inner pane.If the side pane has a connecting section which extends beyond the composite according to the invention and is formed only by the outer pane or only by the inner pane, the said external surfaces are the outside and the inside surface of that outer pane or inner pane, respectively.

[0071] The side window according to the invention is transparent, allowing for a view through. The side window preferably has a light transmission of at least 70%. This allows the side window to be used without any problems as a front side window (side window of the driver and passenger seats), for which legal minimum requirements regarding light transmission exist. Light transmission refers to the total transmission, determined by the light transmission factor (ECE-R 43, Annex 3, § 1).

[0072] 9.1 specified procedures for testing the light transmittance of motor vehicle windows.

[0073] The outer pane, the inner pane, the aerogel layer, and any connecting layers, as well as any coatings, are suitably designed to ensure the desired light transmission. The outer pane, the inner pane, the aerogel layer, and any connecting layers are preferably clear and colorless. However, they may independently exhibit slight tints or colorations, as long as the light transmission is not excessively reduced. The spacer is also preferably clear and transparent, at least if it is visible through the side pane and not obscured by opaque prints.

[0074] The side window can be flat, cylindrical, or spherically curved. Spherically curved side windows are particularly common in passenger cars.

[0075] The side pane according to the invention can be manufactured by connecting the spacer to the outer pane and the inner pane via connecting layers, with the aerogel layer being surrounded by the spacer. The aerogel layer can be provided as a prefabricated block or plate and can also be connected to one of the two panes via a connecting layer, preferably via a connecting layer to the outer pane and to the inner pane. If the aerogel layer is connected to the outer pane and / or the inner pane via a connecting layer, the connecting layer is preferably the same connecting layer with which the spacer is connected to the respective pane.Alternatively, the aerogel layer can be produced directly on the outer pane or the inner pane, so that the pane in question is already provided with the aerogel layer adhered to it and is then connected to the other pane via the spacer.

[0076] If the connecting layers are thermoplastic layers, the bonding is achieved using known lamination processes, for example, autoclave processes, vacuum bag processes, vacuum ring processes, calender processes, vacuum laminators, or combinations thereof. The bonding of the outer pane and inner pane is typically achieved under the influence of heat, vacuum, and / or pressure. The invention further encompasses the use of a vehicle side window according to the invention as a side window of a motor vehicle, preferably a passenger car or truck, in particular as a side window that can be raised and lowered. The side window is particularly advantageously used in electric vehicles, where the reduced energy consumption it achieves leads to a longer battery life.

[0077] The invention further encompasses a vehicle equipped with the vehicle side window according to the invention. The side window is preferably a raising and lowering side window. The vehicle can, in principle, be any land, air, or water vehicle. The vehicle is preferably a motor vehicle or rail vehicle, particularly preferably a passenger car or truck, in particular an electric vehicle (electric passenger car).

[0078] 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:

[0079] Fig. 1 is a plan view of an embodiment of the vehicle side window according to the invention,

[0080] Fig. 2 shows a cross section along XX' through the vehicle side window from Figure 1,

[0081] Fig. 3 is a plan view of a further embodiment of the vehicle side window according to the invention,

[0082] Fig. 4 shows a cross-section along YY' through the vehicle side window from Figure 3,

[0083] Figure 1 and Figure 2 each show a detail of an embodiment of the vehicle side window S according to the invention. The side window S is intended as an openable (i.e., raiseable and lowerable) side window for the front side window of a passenger car.

[0084] The side window S comprises an outer pane 1 and an inner pane 2, between which a frame-like spacer 4 and an aerogel layer 3 are arranged circumferentially in an edge region of the side window S. The spacer 4 and the aerogel layer 3 are connected to the outer pane 1 via a first connecting layer 5a and to the inner pane 2 via a second connecting layer 5b. In the installed position, the outer pane 1 faces the exterior environment of the vehicle, while the inner pane 2 faces the vehicle interior.

[0085] The outer pane 1 and the inner pane 2 are thermally toughened glass panes made of soda-lime glass, each 2.1 mm thick. The connecting layers 5a, 5b are thermoplastic layers and each formed as 0.76 mm thick PVB films. The aerogel layer 3, for example, has a thickness of 2 mm and is made of a transparent polymer aerogel. The spacer 4 is made of transparent polycarbonate (PC). It has a width of 5 mm and a height (dimension between outer pane 1 and inner pane 2) of 2 mm.

[0086] Aerogel layer 3 has thermally insulating properties, reducing heat conduction through the side window. This reduces the heat transfer from the inner pane 2 and the vehicle interior when exposed to sunlight. Likewise, heat loss from the interior through the side window is reduced in winter. Aerogel layer 3 thus increases thermal comfort in the vehicle interior. Aerogel layer 3 is lightweight, keeping the overall weight of the side window low. Aerogel layer 3 also has acoustically insulating properties, shielding from disturbing outside noise.

[0087] An IR-reflective coating 6 is applied as a sun protection coating to the surface of the outer pane 1 facing the aerogel layer 3 and the inner pane 2. An IR-reflective coating 7 is applied as an emissivity-reducing coating to the surface of the inner pane 2 facing the aerogel layer 3 and the outer pane 1. The IR-reflective coating 6 is intended in particular to reflect infrared components of solar radiation and to reduce heating of the layers of the side window and the vehicle interior located behind it as a result of this direct solar radiation. The IR-reflective coating 7 is intended in particular to reflect the thermal radiation from the heated outer pane 1 and aerogel layer 3 at high outside temperatures and to reflect the thermal radiation emanating from the vehicle interior at lower outside temperatures.The IR-reflective coatings 6, 7 further improve thermal comfort in the vehicle interior. The IR-reflective coatings 6, 7 are each thin-film coatings with two silver layers, each embedded between two dielectric layer sequences, so that a dielectric layer sequence is arranged above the top silver layer, below the bottom silver layer, and between the two silver layers.

[0088] The side pane S is completely transparent with a light transmission of over 70%. The outer pane 1, the inner pane 2, the aerogel layer 3, the spacer 4, and the connecting layers 5a, 5b are clear, untinted, and colorless.

[0089] Two retaining elements 10 are attached to the lower edge of the side window S, which faces downwards in the installed position. These serve to connect the side window S to the mechanism for raising and lowering the side window S in the vehicle body. The retaining elements 10 are Y-shaped and have two parallel contact sections, one contact section being adhesively bonded to the surface of the outer window 1 facing away from the aerogel layer 3, and the other contact section being adhesively bonded to the surface of the inner window 2 facing away from the aerogel layer 3. The retaining elements also have a fastening section adjoining the contact sections. The fastening section is provided with a feedthrough 11, which can be connected to the raising and lowering mechanism by means of a component clamped or screwed therein.

[0090] Figure 3 and Figure 4 each show a detail of a further embodiment of the vehicle side window S according to the invention.

[0091] The side pane S can be conceptually divided into a window area D and a connecting area A. In the window area D, the side pane S comprises an outer pane 1 and an inner pane 2, between which a frame-like spacer 4 is arranged circumferentially in an edge area of ​​the window area D and an aerogel layer 3.

[0092] The outer pane 1 is a thermally toughened glass pane made of soda-lime glass with a thickness of 2.1 mm. The inner pane 2 is a chemically toughened glass pane made of aluminosilicate glass with a thickness of 0.6 mm. The aerogel layer 3 is produced directly on the surface of the inner pane 2 facing the outer pane 1 and therefore adheres to it. There is a gap of approximately 0.1 mm between the outer pane 1 and the aerogel layer 3. Alternatively, the aerogel layer 3 can be directly applied to the outer pane 1, which is preferred in order to optimize the thermal insulation properties. The spacer 4 is connected to the outer pane 1 via a first connecting layer 5a and to the inner pane 2 via a second connecting layer 5b. The connecting layers 5a, 5b are thermoplastic layers, each consisting of a 0.38 mm thick PVB film. The aerogel layer 3, for example, has a thickness of 2.6 mm and is made of a transparent polymer aerogel.The spacer 4 is made of transparent polycarbonate (PC). It has a width of 5 mm and a height (dimension between outer pane 1 and inner pane 2) of 2 mm.

[0093] An IR-reflective coating 6 is applied as a sun protection coating to the surface of the outer pane 1 facing the aerogel layer 3 and the inner pane 2. An IR-reflective coating 7 is applied as an emissivity-reducing coating to the surface of the inner pane 2 facing the aerogel layer 3 and the outer pane 1. The IR-reflective coatings 6, 7 are designed exactly as in the configuration shown in Figures 1 and 2.

[0094] The connecting section A is formed only by the outer pane 1, which extends beyond the inner pane 2. Near the lower edge, the outer pane 1 has two openings 11, which serve to connect to the mechanism for raising and lowering the side window S in the vehicle body. A component can be clamped or screwed into the openings 11 for this purpose.

[0095] The combinations of features shown are merely examples and do not limit the invention in any way. For example, instead of feedthroughs 11, a holding element 10 as in Figures 1 and 2 can be provided for the side pane S of Figures 3 and 4. Conversely, the side pane S of Figures 1 and 2 could be provided with feedthroughs 11 instead of being equipped with holding elements 10. Likewise, the aerogel layer 3 of the side pane S of Figures 3 and 4 could be connected to the outer pane 1 and the inner pane 2 via connecting layers 5a, 5b, while the aerogel layer 3 of the side pane S of Figures 1 and 2 could be produced directly on a pane surface instead of being connected to the outer pane 1 and the inner pane 2 via connecting layers 5a, 5b.The combinations of outer pane 1 and inner pane 2 are also merely examples; alternatively, for example, non-tempered glass panes or plastic panes can be used as outer pane 1 and / or inner pane 2.

[0096] The energy input through the side window S was determined through simulations. To characterize this, the so-called thermal transmittance coefficient, commonly referred to as the ll value, was determined. The lower the ll value, the lower the thermal transmittance.

[0097] There were:

[0098] Example of a side window S according to the invention with a 3 mm thick

[0099] Aerogel layer 3 and an IR-reflecting coating 6 on the interior surface of the outer pane 1;

[0100] Comparative example of a corresponding side pane made of the same outer pane 1, the same inner pane 2 with the same IR-reflecting coating 6 on the interior-side surface of the outer pane 1, but without aerogel layer 3 and spacer 4; outer pane 1 and inner pane 2 were laminated to form a composite pane using a 0.76 mm thick PVB film.

[0101] In the comparison example, the simulated U-value was 5.62 W / (m 2 K), in the example according to the invention only 2.34 W / (m 2 K). Aerogel layer 3 therefore leads to a significant reduction in the thermal transmittance.

[0102] List of reference symbols:

[0103] (5) Vehicle side window

[0104] (1) Outer pane

[0105] (2) Inner pane

[0106] (3) Aerogel layer

[0107] (4) Spacers

[0108] (5a) first connecting layer

[0109] (5b) second connecting layer

[0110] (6) IR-reflective coating (sun protection coating)

[0111] (7) IR-reflective coating (emissivity-reducing coating)

[0112] (10) Holding element

[0113] (11) Implementation

[0114] (D) Window area

[0115] (A) Connection area

[0116] X - X' intersection line

[0117] Y - Y' intersection line

Claims

Patent claims 1. Vehicle side window (S), comprising an outer pane (1) and an inner pane (2) which are connected to one another via a frame-like spacer (4), so that a cavity delimited by the outer pane (1), the inner pane (2) and the spacer (4) is formed, wherein an aerogel layer (3) is arranged in the cavity.

2. Vehicle side window (S) according to claim 1, wherein the aerogel layer (3) is connected via a connecting layer (5a, 5b) at least to the outer pane (1) or the inner pane (2), preferably via a connecting layer (5a, 5b) each to the outer pane (1) and the inner pane (2).

3. Vehicle side window (S) according to claim 1, wherein the aerogel layer (3) is produced on the surface of the outer pane (1) or the inner pane (2).

4. Vehicle side window (S) according to one of claims 1 to 3, wherein the outer pane (1) and the inner pane (2) are designed independently of one another as - thermally toughened glass pane, - non-tempered glass pane, - chemically toughened glass pane or - plastic disc.

5. Vehicle side window (S) according to one of claims 1 to 4, wherein the spacer (4) is formed from a polymer, in particular from a transparent polymer, preferably based on polycarbonate, PMMA, PET, PVC or polystyrene.

6. Vehicle side window (S) according to one of claims 1 to 5, wherein the spacer (4) has a width of 3 mm to 10 mm.

7. Vehicle side window (S) according to one of claims 1 to 6, wherein the aerogel layer (3) has a thickness of 0.1 mm to 10 mm, particularly preferably 0.5 mm to 6 mm, most preferably 1 mm to 4 mm.

8. Vehicle side window (S) according to one of claims 1 to 7, wherein the aerogel layer (3) is formed on the basis of a silicate aerogel, a polymer aerogel or a cellulose aerogel.

9. Vehicle side window (S) according to one of claims 1 to 8, wherein an IR-reflecting coating (6) is applied to the surface of the outer pane (1) facing the aerogel layer (3), preferably comprising at least two silver-based layers.

10. Vehicle side window (S) according to one of claims 1 to 9, wherein an IR-reflecting coating (7) is applied to the surface of the inner pane (2) facing the aerogel layer (6), preferably comprising at least two silver-based layers.

11. Vehicle side window (S) according to one of claims 1 to 10, wherein a connecting section (A) of the outer pane (1) provided for connection to a vehicle body projects beyond the inner pane (2) or wherein a connecting section of the inner pane (2) provided for connection to a vehicle body projects beyond the outer pane (1).

12. Use of a vehicle side window (S) according to one of claims 1 to 11 as a liftable and lowerable side window of a motor vehicle, preferably a passenger car or truck, in particular an electric vehicle.

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