Method for laminating composite panels comprising functional elements having electrically switchable optical properties

Abstract

A method for producing a composite panel (1) having a functional element (2) with electrically switchable optical properties, wherein at least a) a first layer stack is created in this order from at least ‑ a first panel (7), ‑ a first thermoplastic composite film (9.1), ‑ at least one insulating film (10), ‑ a second thermoplastic composite film (9.2), ‑ a second panel (8), b) the first layer stack from step a) is laminated under heating, c) the first panel (7) having the first thermoplastic composite film (9.1) is removed from the second panel (8) having the second thermoplastic composite film (9.2) and the at least one insulating film (10) is laminated to the second panel (8). The invention relates to a method for preparing a composite plate comprising: removing the film (10) from the layer stack, d) providing a functional element (2) comprising an active layer (3), e) placing the functional element (2) into the layer stack, thereby forming a second layer stack consisting of at least a first plate (7), a first thermoplastic composite film (9.1), a functional element (2), a second thermoplastic composite film (9.2), and a second plate (8), and f) laminating the second layer stack into a composite plate (1), wherein the at least one insulating film (10) can be detached from the first thermoplastic composite film (9.1) and the second thermoplastic composite film (9.2) without residue.

Description

Technical Field

[0001] The invention relates to a method for producing a composite pane comprising functional elements having electrically switchable optical properties, a composite pane obtainable according to this method, and the use thereof. Background Art

[0002] Glass windows (Verglasungen) with electrically switchable optical properties are known. Such glass windows contain functional elements, which typically contain an active layer between two planar electrodes. The optical properties of the active layer can be changed by applying a voltage to the planar electrodes. Functional elements based on liquid crystals, which are also known as liquid crystal elements, belong to the electrically switchable functional elements used, in particular, in the automotive field. For example, PDLC elements (polymer dispersed liquid crystals) belong to liquid crystal elements, the active layer of which includes liquid crystals inserted into a polymer matrix. PDLC functional elements are known, for example, from DE 102008026339 A1. Another group of liquid crystal elements is a liquid crystal cell constructed as a so-called guest-host cell (Guest-Host-Zelle), which contains dichroic dyes. Here, the liquid crystal is a medium (host) into which the dye (guest) is inserted, wherein the dye is adapted to the preferred direction of the liquid crystal with respect to its spatial orientation. The liquid crystal mixture with the dichroic dye is introduced between two carrier films, which respectively include a conductive layer and an orientation layer as planar electrodes. Here, the orientation layer predetermines the preferred orientation of the liquid crystal in the current-free state. When a voltage is applied to the planar electrodes, the liquid crystal changes its orientation, wherein the dye inserted between the liquid crystal molecules undergoes the same change in its orientation. The optical properties of the liquid crystal cell with the inserted dye are therefore variable depending on the applied electric field, so that the cell (Zelle) can be switched between a transparent state with low turbidity and low hue and an opaque state with low turbidity and high hue. For example, such a guest-host cell comprising a liquid crystal mixture with a dichroic dye is known from WO 2014 / 126974 A1. A glass window with such a functional element can thus be electrically dimmed in a comfortable manner.

[0003] In order to use the guest-host liquid crystal cell in a fail-proof manner, a reliable edge sealing of the cell is required. The edge sealing prevents the liquid crystal material from possibly escaping from the cell laterally. The thickness of the cell is defined via spherical spacers distributed over the entire surface of the cell. For example, a typical cell thickness is 10 μm. Even with a reliable edge sealing in the cell itself and a uniform cell thickness set, the liquid crystal cell is subject to external forces at least during the handling process. Local pressure on small cell areas, for example, causes the liquid crystal material to flow away from this point. Due to the smaller cell thickness occurring at this point, a local reorientation of the liquid crystal occurs, wherein a color shift first occurs in the region of the smaller cell thickness, which results in an uneven appearance. As long as the forces acting locally on the liquid crystal cell are relatively small, a new orientation of the liquid crystal occurs and the liquid crystal element regains its uniform appearance after a short time.

[0004] The described liquid crystal element, which comprises a guest-host liquid crystal cell between two carrier films, is commercially available and enables the manufacture of electrically switchable glazings. The liquid crystal element is typically laminated between two glass plates using conventional methods, whereby a composite plate with electrically switchable optical properties is produced. Deformations of the guest-host liquid crystal cell also occur in the lamination process, wherein the hydrostatic pressure changes that occur in the pressure steaming process have a global effect on the cell and can therefore be classified as non-critical with regard to local deformations and the optical inhomogeneities that arise therewith. In addition to the pressure changes resulting from the application of the pressure steaming process itself, attention should also be paid to the pressures that act on the liquid crystal element from other layers of the layer stack. In particular, in the case of curved glazings, different bendings of the outer and inner plates may occur, which cannot be completely avoided even by bending the plates in a completely consistent manner together. Add the thickness fluctuations of the commonly used thermoplastic composite films. The local thickness increase of the plates and the composite films is transferred to the liquid crystal cell in the lamination process, thereby forming local pressures that occur with the described optical inhomogeneities. Local pressure points cause deformations of the liquid crystal cell.

[0005] The described problems, which occur as soon as no overlapping surfaces are provided at the interface between the functional element and the thermoplastic intermediate layer, are present not only in the case of guest-host liquid crystal cells, but can also occur in the case of other functional elements with electrically switchable optical elements. The extent of the resulting quality reduction depends in particular on the design of the functional element.

[0006] EP 0825478 A1 describes a composite pane which comprises a functional element with electrically controllable optical properties, wherein the functional element contains liquid-crystal domains with a dichroic dye.

[0007] EP 0964288 A2 discloses a glazing comprising a functional element with electrically controllable optical properties, the functional element comprising liquid crystals and a dichroic dye, wherein the decomposition of the dichroic dye is to be reduced by photoreduction.

[0008] One possible solution for improving the optical quality of composite panels with functional elements is to use a resin, which can be used to laminate the functional elements. Thus, for example, UV-curing acrylic resins are known by the term OCA (optically clear adhesive). These UV-curing acrylic resins are provided in the form of films between two transfer films, wherein the transfer films are only used to apply the OCA to the board or other substrates. Although these resinous films can cause certain optical improvements, it is not possible to completely solve the described doubts in all cases. In addition, it is desirable to be able to achieve optical improvements not only when using resin-based films, but also to be able to use these films and also other composite films from commonly used composite films. Summary of the invention

[0009] The object of the present invention is to provide a method for producing a composite pane comprising a functional element with electrically switchable optical properties, wherein localized pressure application to the functional element is avoided, and to provide a composite pane comprising such a functional element. The composite pane should comprise a functional element of as uniform a thickness as possible, which has good optical quality without visible inhomogeneities.

[0010] According to the invention, the object of the invention is achieved by a method for producing a composite pane with functional elements, a composite pane produced according to this method, and the use thereof. Preferred embodiments of the invention are apparent from the further examples.

[0011] The method for producing a composite plate with a functional element comprises as a basic step: constructing a first layer stack from a plate and a thermoplastic composite film, the first layer stack containing a reversibly detachable isolation film; removing the isolation film and subsequently laminating the composite plate with the functional element, wherein the functional element is placed at the location of the removed isolation film. The thermoplastic composite film surrounding the functional element is preformed in this way before receiving the functional element. The required method steps are described in detail below. In the first step of the method according to the invention, a first layer stack is created in this order at least from a first plate, a first thermoplastic composite film, at least one isolation film, a second thermoplastic composite film and a second plate. The first layer stack thus produced is laminated under heating in a first lamination step. The first lamination step is not yet used for the final production of the composite plate, but only for constructing two uniform surfaces in the layer stack, which receive the functional element in the later composite plate. Only in the second lamination step are the functional elements placed and the layer stack laminated into a composite plate. In the first lamination step, the first thermoplastic composite film and the second thermoplastic composite film are at least partially melted, whereby the first thermoplastic composite film and the second thermoplastic composite film adhere to the respectively adjacent plates. The melting of the composite films causes thermoplastic flow of the material of the composite films, whereby unevenness and manufacturing tolerances of the composite films and the plates are equalized by the migration of the melt. The first thermoplastic composite film and the second thermoplastic composite film are separated from each other by at least one barrier film during the lamination of the first layer stack, so that the first thermoplastic composite film is prevented from fusing with the second thermoplastic composite film. The barrier film is a film-like material that does not melt in the lamination method, which can be detached from the first thermoplastic composite film and the second thermoplastic composite film without residue and has only a small adhesion to the first thermoplastic composite film and the second thermoplastic composite film. By using at least one barrier film, the first plate with the first thermoplastic composite film can be removed from the second plate with the second thermoplastic composite film in a simple manner in the subsequent step. When the first plate with the associated composite film is removed, at least one barrier film remains on one of the surfaces of the composite film that face each other in the layer stack and can subsequently be peeled off from the composite film. Due to the low adhesion of the barrier film to the thermoplastic composite film, these components only show low adhesion to each other, which makes it possible to remove without residue. In this way, the barrier film is removed from the layer stack. The first plate with the first thermoplastic composite film laminated thereon and the second plate with the second thermoplastic composite film laminated thereon remain. In the subsequent sequence of steps, the actual composite plate with the functional element laminated therein is produced. First, a functional element is provided. The functional element is placed on the first thermoplastic composite film of the first plate or the second thermoplastic composite film of the second plate and covered with the second thermoplastic composite film with the second plate or with the first thermoplastic composite film with the first plate.The two thermoplastic composite films surround the functional element, wherein the second layer stack is composed in this order at least of the first pane, the first thermoplastic composite film, the functional element, the second thermoplastic composite film and the second pane. Finally, the second layer stack is laminated to form the composite film.

[0012] In the composite plate manufactured by means of the method according to the invention, local pressure points of the functional element are avoided, whereby the functional element has a uniform thickness, which results in good optical quality without visible inhomogeneities. In the first lamination step of the method, in which the components of the composite plate are laminated without the functional element and with the insulating film placed at the position of the functional element, the thermoplastic composite film has already begun to flow and thus forms a uniform surface. The thermoplastic composite film itself has considerable manufacturing tolerances in its thickness in part. This also applies to a lesser extent to the plates used, where tolerances occur especially when three-dimensionally curved plates are used. In the first lamination step of the method according to the invention, local thickness deviations are balanced so that the maximum plane parallelism can be achieved at the position of the functional element. Here, the material of the thermoplastic composite film flows from the plate area with too high a layer thickness of the thermoplastic composite film and / or the adjacent plate to the plate area with too small a layer thickness. Therefore, the manufacturing tolerances of the plate and the composite film are balanced, and the composite film surface for receiving the functional element after removing the insulating film has high plane parallelism without undesirable local protrusions or recesses. This avoids local pressure points of the functional element. Without such a first lamination step, for example, a local increase in thickness of the plate would press against the functional element. As a result, the material of the active layer of the functional element is pushed away at this point and causes optically visible inhomogeneities. Although the material of the thermoplastic composite film can also flow in the second lamination step, the manufacturing tolerances are not compensated quickly enough, so that corresponding damages are formed in the liquid crystal element. These damages are avoided by means of the method according to the invention.

[0013] A wide variety of film-like materials can be used as release films as long as they do not melt at the temperatures usually used in lamination processes, especially in pressure-steam processes, and adhere only slightly to the adjacent thermoplastic composite film. Preferably, release films made of chemically inert materials with a melting temperature of more than 150° C. are used. The release film particularly preferably comprises polyhalogenated olefins, especially polytetrafluoroethylene. Polyhalogenated olefins and especially polytetrafluoroethylene are advantageous in terms of their good chemical and mechanical stability and good residue-free releasability from the preferred materials of the thermoplastic composite film.

[0014] In a preferred embodiment of the method according to the invention, at least two barrier films are used, preferably exactly two barrier films. This results in a first layer stack consisting of at least a first plate, a first thermoplastic composite film, a first barrier film, a second barrier film, a second thermoplastic composite film and a second plate in this order, the first layer stack being connected (verbunden) in the first lamination step. The use of two barrier films is advantageous in terms of simplified removal of the barrier films. If only a single barrier film is used in the first layer stack, the two opposing film surfaces of the barrier film are respectively directly contacted and interact with the composite film. Even in the case of barrier films that exhibit low adhesion to the thermoplastic composite film, this adhesion may be an obstacle when the first layer stack is disassembled using only one barrier film, thereby reducing the automation of the process. When two barrier films are used, an improved disassembly of the first layer stack is provided. Even if the barrier films exhibit low adhesion to the respectively adjacent thermoplastic composite films, this adhesion is thus always greater than the adhesion of the two barrier films to each other. Therefore, in any case, when the first sheet with the first thermoplastic composite film is peeled off, the first separator film remains on the first thermoplastic composite film, while the second separator film continues to be placed on the second thermoplastic composite film. The first separator film and the second separator film can then be peeled off from the composite film by simple means, wherein the low adhesion of the separator film to the composite film also does not cause significant interference with the production process.

[0015] In a preferred embodiment of the method according to the invention, the first and / or second separating film, preferably both separating films, in at least one edge section, preferably extend substantially circumferentially beyond the circumferential common edge of the plate. As a result, the separating film or films can be picked up mechanically or manually in the region extending beyond the plate edge in order to start separating the first layer stack. This simplifies the separation of the first layer stack.

[0016] The functional element with electrically controllable optical properties typically includes an active layer between two planar electrodes. The active layer has controllable optical properties, which can be controlled via a voltage applied to the planar electrodes. The planar electrodes and the active layer are typically arranged substantially parallel to the surface of the first plate and the second plate. The planar electrodes are electrically connected to an external voltage source in a manner known per se. Electrical contact is achieved by a suitable connecting cable, for example a thin film conductor, such as a so-called FPC terminal, which is optionally connected to the planar electrodes via a so-called bus conductor (bus bar), for example a strip of conductive material or a conductive printed material.

[0017] In a particularly preferred embodiment, the functional element is a liquid crystal element and comprises as active layer a guest-host liquid crystal cell with a dichroic dye. The method according to the invention is particularly suitable for incorporating such a functional element.

[0018] In other possible configurations, the active layer is a PDLC, SPD, electrochromic or electroluminescent layer.

[0019] In one possible embodiment, the functional element is a PDLC functional element (polymer dispersed liquid crystal). The active layer of the PDLC functional element contains liquid crystals inserted into a polymer matrix. If no voltage is applied to the planar electrodes, the liquid crystals are oriented in a disordered manner, which leads to strong scattering of light passing through the active layer. If a voltage is applied to the planar electrodes, the liquid crystals are oriented in a common direction and the transmission of light through the active layer is increased. Such a functional element is known, for example, from DE 102008026339 A1.

[0020] An SPD functional element (suspended particle device) comprises an active layer comprising suspended particles, wherein the absorption of light by the active layer can be changed by applying a voltage to planar electrodes. The absorption change is based on the orientation of the rod-shaped particles in the electric field when the voltage is applied. SPD functional elements are known, for example, from EP 0876608 B1 and WO 2011033313A1.

[0021] For electrochromic functional elements, the active layer of the functional element is an electrochemically active layer. The transmission of visible light is related to the degree of insertion of ions into the active layer, wherein ions are provided, for example, by an ion storage layer between the active layer and the planar electrode. The transmission can be affected by a voltage applied to the planar electrode, which causes ion migration. Suitable functional layers, for example, contain at least tungsten oxide or vanadium oxide. Electrochromic functional elements are known, for example, from WO2012007334A1, US20120026573 A1, WO 2010147494 A1 and EP 1862849 A1.

[0022] For electroluminescent functional elements, the active layer contains an electroluminescent material, in particular an organic electroluminescent material, whose luminescence is stimulated by applying a voltage. Electroluminescent functional elements are known, for example, from US2004227462 A1 and WO 2010112789A2. Electroluminescent functional elements can be used as simple light sources or as displays with which any representation can be displayed.

[0023] The first thermoplastic composite film and the second thermoplastic composite film are suitable for establishing bonding connection between each other and with adjacent plates and / or adjacent functional elements due to their thermoplastic properties. During the lamination process, the thermoplastic film begins to flow under the action of heat, so that the thermoplastic film adheres to the adjacent elements, not only with these elements but also with the liquid crystal element placed therein. The first and second thermoplastic films preferably contain polyvinyl butyral (PVB), ethylene vinyl acetate (EVA), polyurethane (PU), cycloolefin polymer (COP) and / or its copolymer or mixture, and particularly preferably contain PVB. These materials are common for the thermoplastic interlayer of the composite plate, and establish bonding connection with the glass. Therefore, good connection is guaranteed. The name "composite film" usually means a single-layer or multi-layer polymer film-like film, which connects the plates of the composite plate to each other in a planar manner, wherein this composite function is named for the film. The composite plate usually includes two plates, wherein the composite of the plates is only realized by the composite film placed between the plates and its adhesion in the lamination process.

[0024] In a preferred embodiment of the method according to the invention, the first thermoplastic composite film and / or the second thermoplastic composite film, preferably both thermoplastic composite films, each contain at least one plasticizer.

[0025] Plasticizers are compounds that make plastics softer, more flexible, more ductile and / or more elastic. The plasticizers shift the thermoelastic range of plastics toward lower temperatures so that the plastics have the desired more elastic properties within the range of operating temperatures. Preferred plasticizers are carboxylic acid esters, especially non-volatile carboxylic acid esters, fats, oils, soft resins and camphor. Other plasticizers are preferably aliphatic diesters of triethylene glycol or tetraethylene glycol. It is particularly preferred to use 3G7, 3G8 or 4G7 as plasticizers, wherein the first digit represents the number of ethylene glycol units and the last digit represents the number of carbon atoms in the carboxylic acid part of the compound. Thus, 3G8 represents triethylene glycol bis(2-ethyl hexanoate), i.e. a compound representing the formula C4H9CH(CH2CH3)CO(OCH2CH2)3O2CCH(CH2CH3)C4H9.

[0026] The first thermoplastic composite film and / or the second thermoplastic composite film, preferably both films, preferably contain at least 25% by weight (Gew.-%), preferably at least 30% by weight and in particular at least 40% by weight of plasticizer. The plasticizer contains triethylene glycol bis(2-ethyl hexanoate) or preferably consists of it. For example, polyvinyl butyral films sold under the name High-Flow-PVB have proven to be very suitable in the method according to the invention, and the polyvinyl butyral films have a higher plasticizer content than conventional thermoplastic composite films. The higher plasticizer content causes improved fluidity of the material when melted in the lamination process. The material of the composite film, which becomes softer as the plasticizer content increases, can also be better adapted to the surface and contour of the board and functional element in the second lamination step.

[0027] The first thermoplastic composite film and / or the second thermoplastic composite film can each consist of one or more polymer films. The thermoplastic composite films can also each include a plurality of polymer layers having different or identical properties. The composite plate can include a first thermoplastic composite film and a second thermoplastic composite film, or can also include a plurality of first and / or second thermoplastic composite films. Instead of the first and / or second thermoplastic composite film, there can therefore also be a two-layer, three-layer or multi-layer film stack consisting of a thermoplastic composite film and / or other functional films, wherein the individual films have identical or different properties. The thermoplastic composite film can also consist of segments of different thermoplastic films, the sides of which are adjacent to each other.

[0028] In a preferred embodiment, the first thermoplastic composite film and / or the second thermoplastic composite film may respectively include at least two outer polymer layers and at least one inner polymer layer located between the outer polymer layers, wherein the inner polymer layer has greater plasticity or elasticity than the outer polymer layer. This layer structure is also used as a sound damping thermoplastic interlayer of a composite panel. The sound damping thermoplastic interlayer has a soft core, wherein the rigidity of the layer structure increases from the core of the inner polymer layer to the surface of the outer polymer layer facing away from the inner polymer layer. The inner polymer layer has a thickness of 0.05 mm to 0.40 mm and the outer polymer layer has a thickness of 0.20 mm to 0.60 mm, wherein the total thickness of the sound damping interlayer is at least 0.50 mm, preferably at least 0.70 mm.

[0029] The inner polymer layer with higher elasticity is primarily responsible for the acoustic damping, while the outer polymer layer with lower elasticity contributes decisively to the stabilization of the pane. The use of such acoustically damping thermoplastic intermediate layers as the first and / or second thermoplastic composite film is advantageous in terms of applying pressure as evenly as possible to the functional elements to be integrated. In this case, the soft inner polymer layer of the composite film takes over the function of equalizing the local thickness increase at the surface of the pane facing the thermoplastic composite film due to its higher elasticity. Local pressure points at the functional elements are thereby avoided and the optical quality of the produced glazing is improved.

[0030] The acoustic properties of the acoustically damping thermoplastic interlayer are preferably determined via a so-called mechanical impedance measurement (MIM, mechanical impedance measurement). This is a standardized method referred to in ISO 16940, from which the damping can be calculated by measuring the natural frequency. According to the standard, the acoustically damping interlayer to be tested is laminated between two glass panes with a thickness of 2.1 mm in order to be able to achieve a corresponding comparability in the case of different glass thicknesses. This enables a person skilled in the art to select a suitable interlayer based on well-known standardized measurement methods.

[0031] The mechanical impedance measurement was carried out at the earliest one month after the production of the composite glass. Furthermore, the interlayer itself was laminated to the composite glass with two glass sheets of 2.1 mm thickness at the earliest one month after the production of the interlayer. This ensured that a stable state was established at the time of the measurement.

[0032] It has been shown that acoustically damping thermoplastic interlayers with specific damping coefficients are particularly suitable for carrying out the method according to the invention. In a preferred embodiment of the thermoplastic composite film, these are acoustically damping thermoplastic interlayers for which it is suitable that the damping coefficient η1 of the first mode and the damping coefficient η2 of the second mode of a composite glass pane consisting of two glass panes with a thickness of 2.1 mm each and with a surface of 25 mm×300 mm are η1≥0.20 and η2≥0.25, preferably η1≥0.25 and η2≥0.30, particularly preferably η1≥0.25 and η2≥0.35 in a mechanical impedance measurement (MIM) according to ISO 16940 at a temperature of 20° C.

[0033] The outer polymer layer and the inner polymer layer contain at least polyvinyl butyral (PVB), ethylene vinyl acetate (EVA), polyurethane (PU) or mixtures or copolymers or derivatives thereof which have proven to be suitable for composite glazing.

[0034] In a preferred embodiment, the outer polymer layer and the inner polymer layer comprise polyvinyl butyral and a plasticizer. The choice of the plasticizer and the degree of acetalization of the polyvinyl butyral make it possible to influence the elasticity of the polymer layers in a manner known to those skilled in the art.

[0035] The inner polymer layer preferably has a thickness of 0.07 mm to 0.30 mm, particularly preferably 0.10 mm to 0.20 mm, very particularly preferably about 0.15 mm, while the outer polymer layer has a thickness of 0.30 mm to 0.40 mm, particularly preferably about 0.35 mm. In a preferred configuration of the invention, the outer polymer layers have the same thickness. Alternatively, the outer polymer layers can also differ from one another in their thickness.

[0036] In a possible embodiment of the present invention, in method step e), the thermoplastic frame film edging the functional element is arranged between the first thermoplastic composite film and the second thermoplastic composite film. In the plate area opposite the side of the functional element, the thermoplastic frame film is therefore placed in the layer stack in a circumferential manner. The frame film is constructed with a gap in a frame-like manner, and the functional element is placed in the gap. The frame film can correspond to the first and / or second thermoplastic composite film in terms of its properties and material composition, wherein the gap has been introduced by punching. Alternatively, the thermoplastic frame film can also be composed of a plurality of film sections around the functional element. The outer side of the thermoplastic frame film is preferably arranged to overlap with the side of the first and second thermoplastic composite films. The thermoplastic frame film can be different from the thickness of the first and / or second composite film in its thickness. The thickness of the thermoplastic frame film is preferably selected so that the thermoplastic frame film has approximately the same thickness as the functional element. Local thickness differences of the composite pane introduced by the spatially confined functional element are thereby compensated, so that cracks in the glass and local stress points of the functional element during lamination can be avoided.

[0037] The frame-shaped film is in contact with the adjacent thermoplastic composite film and fuses with the thermoplastic composite film during the lamination process. However, the individual film components are maintained to the extent that they can also be detected in the laminated composite panel.

[0038] In another preferred embodiment, the material composition of the frame-shaped film is different from the composition of the first and second thermoplastic composite films. In particular, the frame-shaped film may include PET, for example, composed of PET. This is advantageous in order to adapt the hardness of the frame-shaped film to the hardness of the functional element.

[0039] The thickness of the thermoplastic composite film is substantially influenced by the thickness of the functional element, wherein the two thicknesses are particularly preferably exactly the same. In practice, this is usually impossible due to the standardized film thickness of the thermoplastic composite film. In this case, the thickness of the thermoplastic frame-shaped film is selected to be greater than the thickness of the functional element, because otherwise undesirable pressure will be applied to the functional element. Therefore, the thickness of the thermoplastic frame-shaped film is preferably greater than or equal to the thickness of the functional element. This is particularly advantageous if the functional element is implemented as a guest-host liquid crystal cell.

[0040] In another preferred embodiment of the method according to the present invention, the thermoplastic frame-shaped film is not placed in the layer stack. If the functional element has a relatively small thickness and therefore the local thickness difference is small, this is possible for example. Whether the frame-shaped film can be abandoned depends not only on the structural mode of the functional element but also on the geometry of the composite plate to be manufactured. For example, PDLC elements or SPD elements are suitable for use in the case of no frame-shaped film. Other functional elements are also conditionally suitable for lamination in the case of no frame-shaped film. Especially in the case of complex geometries or strong bending in the edge region, small local thickness differences may also promote glass breakage. Therefore, it is not possible to make a general prediction on which thickness difference the thermoplastic frame-shaped film should be used.

[0041] In the method according to the invention, an element comprising a guest-host liquid crystal cell with a dichroic dye is preferably used as a functional element. The liquid crystal element comprises two carrier films, which are arranged at a preferably constant spacing from each other and sealed along their common circumferential edge via a sealing material. The guest-host liquid crystal cell is constructed between the carrier films. On each of the carrier films, a conductive layer is arranged on the surface of the carrier film that is turned to the liquid crystal cell. The conductive layer is used as a planar electrode, and the liquid crystal cell is electrically contacted via the planar electrode. By applying a voltage to the planar electrode, the orientation of the liquid crystal in the electric field is caused. The guest-host liquid crystal cell comprises a liquid crystal as a base medium (host), and the dichroic dye is inserted into the base medium. The inserted dichroic dye is oriented along the preferred direction of the liquid crystal. Due to its dichroism, the inserted dye molecules absorb the incident light according to its orientation. Here, light with a polarization direction parallel to the absorption axis of the dye molecule is strongly absorbed, while light with a polarization direction perpendicular to the absorption axis is only weakly absorbed. Here, the light transmission of the guest-host liquid crystal cell is related to the orientation of the dye molecules, which in turn are affected by the preferred direction of the liquid crystal, which is oriented in the electric field when a voltage is applied. Thus, the liquid crystal element can be switched between an opaque and a transparent state, depending on whether a voltage is applied to the planar electrodes. Here, other factors for the transmission of the liquid crystal element are the absorption coefficient of the inserted dye, the thickness of the cell and the dye concentration. The transparent state and the opaque state are distinguished in the following way, that the transmission is lower in the opaque state than in the transparent state, wherein even in the opaque state there may be a certain transmission and may be desired. A person skilled in the art can adjust this as desired according to the parameters mentioned. The operating voltage of the guest-host liquid crystal cell is related to the cell thickness and the dye concentration.

[0042] The guest-host liquid crystal cell and the liquid crystals and dyes applicable therein are commercially available and known to those skilled in the art. For example, nematic liquid crystals and dichroic dyes, preferably anthraquinone dyes and / or azo dyes, can be used. The orientation of the liquid crystal present in the currentless state is determined by an orientation layer, which is present on a conductive layer directly adjacent to the liquid crystal. For example, a drawn polyimide is used as an orientation layer.

[0043] Besides the active layer and the electrically conductive layer, the functional element can have further layers known per se, for example barrier layers, blocking layers, antireflection layers, protective layers and / or smoothing layers.

[0044] The spacing between the carrier films defines the cell thickness, which is preferably about 5 μm to about 20 μm and particularly preferably about 8 μm to about 12 μm. In order to maintain the cell gap, spacers can be arranged within the volume of the active layer. The spacers are placed between the carrier films, for example, in the form of rods and / or spheres made of glass or plastic. In this case, the sealing material for sealing the edge region of the active layer is arranged adjacent to the surrounding edge in the gap between the carrier films. For example, a two-component epoxy resin is used as the sealing material.

[0045] The first carrier film and / or the second carrier film preferably contain at least one polymer that is not completely melted in the pressure steaming process, preferably polyethylene terephthalate (PET). The first and second carrier films are particularly preferably composed of PET films. The carrier film is preferably transparent. The thickness of the carrier film is preferably 0.025 mm to 0.400 mm, in particular 0.050 mm to 0.200 mm. The conductive layer according to the present invention is preferably arranged on the surface of the carrier film, that is, arranged on exactly one side of the two sides of the carrier film (that is, arranged on its front side or back side). Here, the carrier film is oriented in the liquid crystal element so that the conductive layer is arranged adjacent to the active liquid crystal box and acts as its planar electrode.

[0046] The conductive layer of the carrier film serves as a planar electrode of the functional element and is preferably transparent. The planar electrode preferably contains at least one metal, metal alloy or transparent conductive oxide (transparent conductive oxide, TCO). The planar electrode can, for example, contain silver, gold, copper, nickel, chromium, tungsten, indium tin oxide (ITO), zinc oxide doped with gallium or aluminum and / or tin oxide doped with fluorine or antimony. The planar electrode preferably has a thickness of 10nm to 2μm, particularly preferably 20nm to 1μm, and most preferably 30nm to 500nm.

[0047] The planar electrodes and the active layer are typically arranged substantially parallel to the surfaces of the first and second plates in the composite plate to be produced. The planar electrodes are electrically connected to an external voltage source in a manner known per se. The electrical contact is achieved via a suitable connecting cable, such as a foil conductor, which is optionally connected to the planar electrodes via a so-called bus bar, such as a strip of conductive material or a conductive stamp.

[0048] Prior to method step a), the first and second electrically conductive layers are deposited on the carrier film by methods known per se. Reference may be made here, by way of example, to magnetic field-assisted cathode sputtering. This is particularly advantageous with regard to simple, rapid, cost-effective and uniform coating of the substrate. However, the electrically conductive layers may also be applied, for example, by vapor deposition, chemical vapor deposition (CVD), plasma-assisted vapor deposition (PECVD) or by wet-chemical methods.

[0049] The electrical contacting of the electrically conductive layers by means of busbars or other suitable electrical conductors takes place before lamination of the composite pane, preferably during production of the functional element before sealing the edge region with a sealing material.

[0050] Any prints present, for example opaque cover prints or printed busbars for electrical contacting of the functional elements, are preferably applied using a screen printing method.

[0051] Optionally, the functional element can be divided into different segments that are switchable independently of each other. For this purpose, the conductive layer used as the planar electrode of the liquid crystal box is divided into different segments by means of separation lines, and the segments can be individually controlled via bus conductors respectively arranged in the area of ​​the segments. The separation lines isolate adjacent segments from each other in an electrically conductive manner. In the area of ​​the separation lines, the conductive layer of the carrier film is removed, thereby achieving the electrical isolation effect of the separation lines. The de-coating of each separation line in the conductive layer is preferably carried out by a laser beam. The separation lines can be generated at any point in the method. Here, the separation lines are preferably generated by means of a laser through the carrier film closest to the conductive layer to be processed. The wavelength of the laser radiation of the laser can be appropriately selected so that the conductive layer has a sufficiently high laser radiation absorption and the carrier film has a sufficiently low laser radiation absorption, wherein the separation lines are introduced into the conductive layer using the laser. It is thus advantageous to selectively introduce the separation lines into the conductive layer without damaging the carrier film. It should be taken into account here that due to the focusing of the laser radiation, the power density is much greater in the conductive layer than in the carrier layer.

[0052] It has proven to be advantageous to select the wavelength of the laser radiation in the range of 150 nm to 1200 nm, preferably in the range of 200 nm to 500 nm, particularly preferably in the range of 250 nm to 400 nm when producing the separation lines. It has been shown that this range is particularly suitable for wavelengths when using common conductive layers and common carrier films. The wavelength range of the laser is selected here so that the separation lines are selectively introduced into the conductive layer. The width of the de-coating is preferably 10 μm to 1000 μm, particularly preferably 30 μm to 200 μm and in particular 70 μm to 140 μm. In this range, a particularly clean and residue-free de-coating is performed by the laser beam.

[0053] The lamination of the first layer stack in method step b) and the lamination of the second layer stack in step f) are preferably carried out under the action of heat, vacuum and / or pressure. Methods known per se can be used for lamination, for example the autoclave method, the vacuum bag method, the vacuum ring method, the calendering method, a vacuum laminator or a combination thereof.

[0054] The lamination in step b) and / or f) is preferably carried out in a pressure steam process, particularly preferably at an elevated pressure of about 10 bar to 15 bar and a temperature of 130° C. to 145° C. within a time interval of about 2 hours. In another embodiment, a vacuum bag or vacuum ring process known per se is used in step b) and / or f), which operates, for example, at about 200 mbar and 80° C. to 110° C. Alternatively, a vacuum laminator can be used. The vacuum laminator consists of one or more heatable and evacuable chambers, in which the first and second sheets are laminated, for example, within about 60 minutes at a reduced pressure of 0.01 mbar to 800 mbar and a temperature of 80° C. to 170° C.

[0055] Methods for producing the functional elements used in the method according to the invention are known to the person skilled in the art and are extensively described in the literature.

[0056] If the functional element is a guest-host liquid crystal element, the carrier films are usually fixed together to form a predetermined gap using epoxy edge seals at the surrounding edges, wherein the spacing of the carrier films determines the thickness of the liquid crystal cell and is limited by the surrounding spacers. The liquid crystal is introduced into the gap, for example, using a vacuum filling process or a drop filling process. In the case of a vacuum filling process, the surrounding edge seal is not continuous and has an opening called a "filling hole". The carrier films with edge seals are then arranged in a vacuum chamber, wherein the air between the carrier films is removed. In the vacuumed gap between the carrier films, the liquid crystal material is introduced into the filling hole, which is sucked into the gap due to capillary forces. This can be accelerated by placing the arrangement at atmospheric pressure after the liquid crystal is introduced into the filling hole. Finally, the filling hole is closed.

[0057] The spacers inserted between the carrier films usually define the spacing of the carrier films in the case of a guest-host liquid crystal cell and thus define the gap between the carrier films and the thickness of the liquid crystal cell. The spacers preferably have a thickness of 5 μm to 50 μm, particularly preferably 5 μm to 20 μm, whereby a corresponding gap is set between the carrier films. The gap between the carrier films should be essentially constant, wherein deviations of up to 20% in the thickness of the spacers can be tolerated.

[0058] The present invention further relates to a composite panel manufactured by the method according to the present invention. The composite panel comprises at least a first panel, a first thermoplastic composite film, a liquid crystal element comprising a guest-host liquid crystal cell with a dichroic dye, a second thermoplastic composite film and a second panel. The first thermoplastic composite film and / or the second thermoplastic composite film respectively have at least two outer polymer layers and an inner polymer layer located between the outer polymer layers, wherein the outer polymer layer has a lower elasticity or plasticity than the inner polymer layer. This is advantageous in terms of applying pressure as uniformly as possible to the liquid crystal element to be integrated. In this case, the soft inner polymer layer of the composite film takes over the balancing function in terms of the local thickness increase at the surface of the panel facing the thermoplastic composite film due to its higher elasticity. Local pressure points at the liquid crystal element are thereby avoided and the optical quality of the manufactured glass window is improved. In this case, the higher elasticity or plasticity of the inner polymer layer of the first and / or second thermoplastic composite film respectively has proven to be particularly advantageous, especially in the case of a guest-host liquid crystal cell that is highly sensitive to pressure points, in order to compensate for possible residual inhomogeneities of the panel surface.

[0059] The features of the composite pane produced thereby, which were explained in the description of the method according to the invention, also apply to the composite pane according to the invention and are not repeated here.

[0060] The liquid crystal element is connected to the first plate via the area of ​​the first thermoplastic composite film and to the second plate via the area of ​​the second thermoplastic composite film. The first and second thermoplastic composite films are preferably arranged in a planar manner overlapping each other and laminated to each other, wherein the liquid crystal element is inserted between the two layers. The area of ​​the thermoplastic composite film overlapping the liquid crystal element then constitutes the area connecting the liquid crystal element to the plate. In other areas of the plate where the thermoplastic composite films are in direct contact with each other, the thermoplastic composite films can fuse during lamination.

[0061] The first and second panels of the composite panel can be curved, for example when used as vehicle glazing. The panels can be bent individually or together. The panels are preferably bent together (i.e. simultaneously and by the same tool) in exactly the same manner, because the shapes of the panels are thereby optimally coordinated with each other for later lamination.

[0062] If the composite pane is to be used as a curved vehicle glazing, at least the pane used as the outer pane is subjected to a bending process before lamination. In a preferred embodiment, the pane used as the inner pane is also subjected to a bending process. This is particularly advantageous in the case of strong bending in multiple directions in space (so-called three-dimensional bending).

[0063] Alternatively, the plate used as inner plate is not pre-bent. This is possible in particular with plates of very small thickness, since they have a film-like flexibility and can therefore be adapted to the pre-bent outer plate without having to be pre-bent themselves.

[0064] The first plate and / or the second plate preferably contain glass, particularly preferably flat glass, float glass, quartz glass, borosilicate glass, soda-lime glass; or contain transparent plastic, preferably rigid transparent plastic, especially polycarbonate, polymethyl methacrylate and / or mixtures thereof. In a possible embodiment, the first plate and / or the second plate are transparent, especially for the use of the plate as a windshield, rear window or rear side window of a vehicle or other uses where high light transmission is desired. However, for plates that are not in the driver's traffic-related field of vision, for example for roof windows, the transmission can also be much lower, for example greater than 5%. In principle, any other plate can be arranged at the outer side surface of the first and second plates and connected to the other plate via lamination under intermediate layering (Zwischenlage) of thermoplastic film or via spacers in the case of insulating glazing.

[0065] In one possible embodiment, the composite panel according to the invention is a wind deflector, wherein the functional element is used as an electrically switchable sun visor.

[0066] In a preferred embodiment, the composite panel according to the invention is a roof window panel or a side window panel.

[0067] The thickness of the first plate and / or the second plate is between 0.3 mm and 10 mm, wherein the plate thickness is strongly dependent on the application of the plate.

[0068] In the automotive sector in particular, there has been a trend in recent years towards ever smaller glass thicknesses, which makes it possible to save weight on vehicles. The sheet thickness of automotive glazing, in particular windshields, is usually in the range of 0.3 mm to 2.5 mm for the inner pane and in the range of 0.8 mm to 2.5 mm for the outer pane. Asymmetrical thickness combinations, in which the thickness of the outer pane is greater than the thickness of the inner pane, are advantageous, especially in the case of a small overall thickness, with regard to improved stability of the composite pane.

[0069] If the composite panel is a windshield, the thickness of the outer panel is preferably between 0.8 mm and 2.1 mm and the thickness of the inner panel is preferably between 0.5 mm and 1.8 mm.

[0070] If the composite pane is a roof panel of a motor vehicle, the thickness of the outer pane is preferably between 1.1 mm and 2.1 mm and the thickness of the inner pane is preferably between 0.5 mm and 1.6 mm.

[0071] The composite glass in its embodiment as a vehicle glazing is preferably curved in one or more directions in space, as is common for motor vehicle panels, with typical radii of curvature being in the range of about 10 cm to about 40 m. However, the composite glass can also be flat, for example when it is provided as a panel for buses, trains, tractors or as a building glazing.

[0072] The first plate and / or the second plate may be thermally or chemically prestressed, partially prestressed or not prestressed.

[0073] Composite glazing can also be provided with additional functions in that the thermoplastic interlayer has functional inserts, for example inserts with infrared absorbing, UV absorbing or coloring properties. Inserts are, for example, organic or inorganic ions, compounds, aggregates, molecules, crystals, pigments or dyes. In particular, a thermoplastic interlayer with UV absorbing properties between a pane serving as an outer pane and a functional element is advantageous in protecting the functional element from UV radiation.

[0074] Particularly when using the composite pane according to the invention in vehicles, it is advantageous to implement further functions in order to reduce the negative effects of weather influences such as strong solar radiation or icing.

[0075] Another aspect of the invention comprises the use of the composite panel according to the invention in vehicles for land, air or water traffic, preferably in trains, ships and motor vehicles, for example as wind deflectors, rear windows, side windows and / or roof windows, particularly preferably as motor vehicle roof windows. BRIEF DESCRIPTION OF THE DRAWINGS

[0076] The invention is described in more detail below based on the accompanying drawings and embodiments. The accompanying drawings are schematic diagrams and are not drawn to scale. The accompanying drawings do not limit the invention in any way.

[0077] Figure 1 shows a cross section through a layer stack of a composite pane during one embodiment of the method according to the invention, Figure 2a A plan view of a composite pane 1 according to the invention with functional elements is shown,

[0078] Figure 2b Shown along the cutting line AA' through the Figure 2a The cross section of the composite plate 1,

[0079] Figure 2c The diagram along the cutting line AA' is shown according to Figure 2a and 2b A fragment Z of a composite panel 1 according to the invention, Figure 2d The diagram along the cutting line AA' is shown according to Figure 2a and2b A fragment Z of a composite panel 1 according to the invention, Figure 3 An embodiment of the method according to the invention is shown. DETAILED DESCRIPTION

[0080] Figure 1 The layer stack composed of a first plate 7, a second plate 8 and thermoplastic composite films 9.1, 9.2 and barrier films 11.1, 11.2 or functional element 2, which is constructed during the method according to the invention, is shown. The individual processing states of the layer stack are denoted here as states A to C. The first layer stack composed of the first plate 7, the first thermoplastic composite film 9.1, the first barrier film 11.1, the second barrier film 11.2, the second thermoplastic composite film 9.2 and the second plate 8 in this order is shown in FIG. Figure 1 In the embodiment shown in Figure 1 , one insulating film 11 is sufficient, wherein the use of two insulating films facilitates the removal of the insulating film 11. The thermoplastic composite films 11.1 and 11.2 each have a thickness of 0.38 mm, whereas the insulating films 11.1 and 11.2 consist essentially of polytetrafluoroethylene and are each 50 μm thick. The plates 7, 8 consist of glass. The first layer stack shown in state A) was laminated at a temperature of 145° C. and a pressure of 12 bar within a time interval of 2 hours. As a result, the thermoplastic composite films 9.1, 9.2 are connected to the adjacent first plate 7 and second plate 8, respectively. The insulating films 11.1 and 11.2 do not show any adhesion to each other, so that the first layer stack can be disassembled between the first insulating film 11.1 and the second insulating film 11.2 without any difficulty. The insulating film 11 shows only very low adhesion to the adjacent thermoplastic composite film 9, so that it is possible to disassemble the layer stack even with only one insulating film. In a first lamination step to which the first layer stack is subjected, the thermoplastic composite film 9 is melted and begins to flow. In this process, the thermoplastic material of the composite film 9 is evenly distributed between the adjacent glass panes and the adjacent insulating film, so that unevenness of the pane surfaces is equalized and the uniform surface of the composite films 9.1, 9.2 is ready for receiving the functional element 2. Figure 1State B) shows a first plate 7 having a first thermoplastic composite film 9.1 laminated thereon and a second plate 8 having a second thermoplastic composite film 9.2 laminated thereon, wherein the first insulating film 11.1 and the second insulating film 11.2 are removed from the layer stack. The functional element 2 is then placed between the first thermoplastic composite film 9.1 and the second thermoplastic composite film 9.2. The second layer stack shown as state C) is thus constructed. The functional element 2 is smaller in size than the plates 7, 8 and the thermoplastic composite films 9.1, 9.2. Here, the circumferential edge of the functional element 2 is offset inwardly in the direction of the center of the surface of the layer stack compared to the circumferential common edge of the plates 7, 8 and the composite film 9. A thermoplastic frame film 10 is placed in the edge region between the circumferential edge of the functional element 2 and the circumferential edge of the plates 7, 8, which surrounds the functional element 2 in a frame-like manner. The use of the frame film 10 is optional. The frame film consists of polyethylene terephthalate (PET), wherein the thickness of the frame film 10 corresponds to the thickness of the functional element 2. The functional element 2 is a guest-host liquid crystal cell having a thickness of 280 μm and comprising a nematic liquid crystal and a dichroic dye as an active layer 3. In the second lamination step, the second layer stack shown in state C) is laminated in a pressure steaming method, resulting in a composite panel 1 according to the invention. The parameters used in the second lamination step can be selected similarly to the parameters used in the first lamination step. However, in principle it is sufficient to be able to achieve melting in the second lamination step.

[0081] Figure 2a , 2b , 2 c and 2 d show views of a composite pane 1 according to the invention having an electrically switchable liquid crystal element as functional element 2 . Figure 2a Shown in accordance with Figure 1 A top view of a composite panel 1 laminated in the method according to the invention. In this regard, unless otherwise described here, Figure 1 The discussion of Figure 1 As described in , the functional element 2 is laminated between a first plate 7 and a second plate 8 by means of two thermoplastic composite films 9 . 1 , 9 . 2 . Figure 2b The view corresponds to Figure 2a A cross section of a composite pane similar to the cross section along the cutting line AA' shown in FIG. A first thermoplastic composite film 9.1 is placed on the first pane 7, followed by the functional element 2. The functional element 2 is covered by the second thermoplastic composite film 9.2 and the layer stack is closed by the second pane 8. The functional element 2 can also be placed only in part of the composite pane 1. Depending on the Figure 2a, the functional element 2 is only placed in the field of view of the composite plate 1, wherein a surrounding edge area is retained, which is free of the functional element 2. Therefore, compared with the surrounding edge of the composite plate 1 composed of the plates 7 and 8, the surrounding edge 12 of the functional element 2 is withdrawn in the direction of the center of the surface of the composite plate 1. A thermoplastic frame film 10 is inserted in the edge area between the surrounding edge 12 of the liquid crystal element 2 and the edges of the plates 7 and 8, and the thermoplastic frame film balances the thickness difference between the edge area without the liquid crystal element 2 and the area with the functional element 2. Of course, additional elements, such as other electrically switchable functional films or other functional elements, may optionally be present. For the sake of simplified representation, the three-dimensional bending of the composite plate is not shown. Figure 2a , 2b , 2c and 2d. However, in particular when the composite panel 1 is used as a vehicle glazing, the three-dimensional curvature is preferably present. The advantages of the method according to the invention with regard to the optical quality of the composite panel 1 are particularly evident in the case of curved composite panels. In particular, the curved panels 7, 8 have inhomogeneities in their thickness, which cause local pressure points at the functional element 2. The local pressure points can be avoided by the first lamination step according to the invention, in which the thermoplastic composite film 9 is pre-laminated with the insulating film 11 without the functional element 2. In the edge region of the composite panel 1, the panels 7, 8 can optionally be provided with an opaque cover print 13 (see Figure 2b ), a thermoplastic frame film 10 is inserted in the edge region. The cover print conceals the frame film 10 and the edge 12 of the functional element 2 so that these are not visible to the observer. Such concealment by means of black print is common to those skilled in the art. The electrical contacting and edge sealing of the liquid crystal element as the functional element 2 are not shown in the figure, but are known to those skilled in the art from the prior art.

[0082] Figure 2c Show Figure 2b An enlarged section Z of FIG. 1 is shown in cross section. Figure 2a Composite panel 1. Here, the detailed layer sequence of the functional element 2 is Figure 2c . The functional element 2 comprises a first carrier film 4.1 and a second carrier film 4.2, wherein a first conductive layer 5.1 is applied on the surface of the first carrier film 4.1, and a second conductive layer 5.2 is provided on the surface of the second carrier film 4.2. Passivation layers and orientation layers (not shown) known in the prior art are located on the conductive layers 5.1, 5.2. Between the conductive layers 5.1, 5.2 there is a liquid crystal cell in the form of a guest-host cell consisting of liquid crystals and dichroic dyes placed therein as an active layer 3. The carrier films 4.1, 4.2 are respectively composed of PET films. The conductive layers 5.1, 5.2 are layers comprising indium tin oxide. The thermoplastic composite films 9.1, 9.2 correspond to Figure 1Thermoplastic composite films described in.

[0083] Figure 2d by Figure 2b Another embodiment of a composite panel 1 is shown in the form of an enlarged section Z of FIG. Figure 2a Another embodiment of a composite panel 1. This modification corresponds essentially to Figure 2c The modification described in the invention, wherein, in contrast thereto, the thermoplastic composite films 9.1, 9.2 are each composed of a multilayer sound-damping composite film. The multilayer sound-damping composite film comprises two outer polymer layers 14, between which an inner polymer layer 15 is arranged. The inner polymer layer 15 has a greater plasticity or elasticity than the outer polymer layer 14. Such a layer structure has proven to be particularly advantageous for use in the method according to the invention. The resulting composite panel 1 has particularly good optical quality, wherein local pressure points at the functional element 2 are avoided.

[0084] Figure 3 A preferred embodiment of the method according to the present invention is shown, the method comprising the following steps: I. placing a first thermoplastic composite film 9.1 on a first plate 7,

[0085] II placing the first barrier film 11.1 onto the first thermoplastic composite film 9.1,

[0086] III. Placing the second insulating film 11.2 onto the first insulating film 11.1,

[0087] IV placing the second thermoplastic composite film 9.2 onto the second barrier film 11.2,

[0088] V placing the second plate 8 onto the second thermoplastic composite film 9.2,

[0089] VI laminating the first layer stack, which consists of

[0090] - first plate 7,

[0091] - a first thermoplastic composite film 9.1,

[0092] - a first insulating film 11.1,

[0093] - a second insulating film 11.2,

[0094] - a second thermoplastic composite film 9.2,

[0095] - Second board 8

[0096] The invention relates to a method for laminating a first sheet 7 and a second sheet 2, wherein the first sheet 7 and the second sheet 2 are laminated under heating in a pressure steaming method, wherein the thermoplastic composite films 9.1, 9.2 are melted and the first thermoplastic composite film 9.1 is adhered to the first sheet 7 and the second thermoplastic composite film 9.2 is adhered to the second sheet 2, VII the second sheet 8 with the second thermoplastic composite film 9.2 and the second insulating film 11.2 is removed from the first sheet 7 with the first thermoplastic composite film 9.1 and the first insulating film 11.1,

[0097] VIII peeling off the first release film 11.1 and the second release film 11.2 from the first thermoplastic composite film 9.1 or the second thermoplastic composite film 9.2 and removing the release films 11.1, 11.2 from the layer stack,

[0098] IX Placing the functional element 2 comprising the active layer 3 on the first thermoplastic composite film 9 . 1 with the first plate 7 connected thereto,

[0099] X placing a second thermoplastic composite film 9.2 with a second plate 8 connected thereto onto the functional element 2, XI laminating a second layer stack under heating in an autoclave process to form a composite panel 1 according to the invention, the second layer stack consisting of - a first plate 7,

[0100] - a first thermoplastic composite film 9.1,

[0101] - Functional element 2,

[0102] - a second thermoplastic composite film 9.2,

[0103] - The second plate 8 is formed.

[0104] Reference numerals list

[0105] 1 Composite board

[0106] 2 Functional elements with electrically switchable optical properties

[0107] 3 Active layer

[0108] 4 Carrier films for functional components

[0109] 4.1 The first carrier film of the functional element

[0110] 4.2 Second carrier film of functional element

[0111] 5 Conductive layer of functional components

[0112] 5.1 First Conductive Layer

[0113] 5.2 Second Conductive Layer

[0114] 7 First Board

[0115] 8 Second board

[0116] 9 Thermoplastic composite film

[0117] 9.1 The first thermoplastic composite film

[0118] 9.2 Second Thermoplastic Composite Film

[0119] 10 frame film

[0120] 11. Isolation film

[0121] 11.1 The first isolation film

[0122] 11.2 Second isolation film

[0123] 12 Surrounding edge of functional element 2

[0124] 13 Opaque overlay print

[0125] 14 Outer polymer layer of thermoplastic composite film 9

[0126] 15 Inner polymer layer of thermoplastic composite film 9

[0127] A-A' cutting line

[0128] Z fragment.

Claims

1. A method for producing a composite pane (1) having a functional element (2) with electrically switchable optical properties, wherein at least a) At least in the following order - a first plate (7), - a first thermoplastic composite film (9.1), - at least one separating film (11), - a second thermoplastic composite film (9.2), - Second board (8) Create the first stack, The first thermoplastic composite film (9.1) and / or the second thermoplastic composite film (9.2) can each be composed of one or more polymer films. b) laminating the first layer stack from step a) under heating, wherein the first thermoplastic composite film (9.1) is adhered to the first pane (7) and the second thermoplastic composite film (9.2) is adhered to the second pane (8), c) removing the first plate (7) with the first thermoplastic composite film (9.1) from the second plate (8) with the second thermoplastic composite film (9.2) and removing the at least one release film (11) from the layer stack, d) providing a functional element (2) comprising an active layer (3), e) placing the functional element (2) on the first thermoplastic composite film (9.1) of the first plate (7) or the second thermoplastic composite film (9.2) of the second plate (8) and covering it with the second thermoplastic composite film (9.2) with the second plate (8) or with the first thermoplastic composite film (9.1) with the first plate (7), thereby at least - a first plate (7), - a first thermoplastic composite film (9.1), - a functional element (2), - a second thermoplastic composite film (9.2), - Second board (8) Forming the second stack, and f) laminating the second layer stack to form a composite panel (1), The at least one barrier film (11) can thereby be removed from the first thermoplastic composite film (9.1) and the second thermoplastic composite film (9.2) without leaving any residue.

2. The method according to claim 1, wherein said at least one barrier film (11) comprises a polyhaloolefin.

3. The method according to claim 2, wherein the at least one isolation film (11) comprises polytetrafluoroethylene.

4. The method according to any one of claims 1 to 3, wherein in step a), at least - a first plate (7), - a first thermoplastic composite film (9.1), - a first insulating film (11.1), - a second insulating film (11.2), - a second thermoplastic composite film (9.2) and - Second board (8) Create the first layer of the stack.

5. The method according to any one of claims 1 to 3, wherein the functional element (2) is a liquid crystal element and comprises a guest-host liquid crystal cell with a dichroic dye as an active layer (3).

6. A method according to any one of claims 1 to 3, wherein the first thermoplastic composite film (9.1) and / or the second thermoplastic composite film (9.2) comprises polyvinyl butyral (PVB), ethylene vinyl acetate (EVA), polyurethane (PU)), cycloolefin polymer (COP) or a copolymer or mixture of polyvinyl butyral (PVB), ethylene vinyl acetate (EVA), polyurethane (PU)), cycloolefin polymer (COP).

7. The method according to claim 6, wherein the first thermoplastic composite film (9.1) and / or the second thermoplastic composite film (9.2) comprises polyvinyl butyral having a plasticizer content of at least 30% by weight.

8. The method according to claim 7, wherein the first thermoplastic composite film (9.1) and / or the second thermoplastic composite film (9.2) comprises polyvinyl butyral having a plasticizer content of at least 40% by weight.

9. A method according to claim 6, wherein the first thermoplastic composite film (9.1) and / or the second thermoplastic composite film (9.2) respectively comprises at least two outer polymer layers (14) and at least one inner polymer layer (15) located between the outer polymer layers, and the outer polymer layer (14) has lower elasticity or plasticity than the inner polymer layer (15).

10. The method according to claim 9, wherein the inner polymer layer (15) has a thickness of 0.07 mm to 0.30 mm.

11. The method according to claim 10, wherein the inner polymer layer (15) has a thickness of 0.10 mm to 0.20 mm.

12. The method according to any one of claims 9 to 11, wherein the outer polymer layer (14) has a thickness of 0.30 mm to 0.40 mm.

13. A method according to any one of claims 1 to 3, wherein in method step e), a frame-shaped film (10) is arranged between the first thermoplastic composite film (9.1) and the second thermoplastic composite film (9.2), and the frame-shaped film borders the functional element (2) along its circumferential edge (12).

14. A method according to any one of claims 1 to 3, wherein the functional element (2) comprises at least one first carrier film (4.1) and a second carrier film (4.2), the active layer (3) is arranged between the first carrier film (4.1) and the second carrier film (4.2), wherein the conductive layer (5.1, 5.2) is arranged on the surface of the first carrier film (4.1) and the second carrier film (4.2) facing the active layer (3).

15. The method according to claim 14, wherein the electrically conductive layer (5.1, 5.2) comprises at least one metal, a metal alloy or a transparent conductive oxide and has a thickness of 10 nm to 2 μm.

16. The method according to claim 15, wherein the conductive layer (5.1, 5.2) comprises a transparent conductive oxide.

17. The method according to claim 14, wherein the first carrier film (4.1) and / or the second carrier film (4.2) comprises at least one polymer which does not melt thermoplastically during the lamination process.

18. The method according to claim 17, wherein the first carrier film (4.1) and / or the second carrier film (4.2) comprises polyethylene terephthalate.

19. The method of claim 5, wherein the guest-host liquid crystal cell with a dichroic dye comprises at least a nematic liquid crystal and a dichroic dye.

20. The method of claim 19, wherein the guest-host liquid crystal cell having a dichroic dye comprises an anthraquinone dye and / or an azo dye.

21. A composite panel (1) manufactured by the method according to any one of claims 1 to 20, comprising at least - a first plate (7), - a first thermoplastic composite film (9.1), - a liquid crystal cell as a functional element (2), said liquid crystal cell comprising a guest-host liquid crystal cell with a dichroic dye as an active layer (3), - a second thermoplastic composite film (9.2), - a second plate (8), The first thermoplastic composite film (9.1) and / or the second thermoplastic composite film (9.2) respectively include at least two outer polymer layers (14) and an inner polymer layer (15) located between the outer polymer layers, and the outer polymer layer (14) has lower elasticity or plasticity than the inner polymer layer (15).

22. Use of a composite pane according to claim 21 in a motor vehicle glazing.

23. The use according to claim 22, wherein the composite panel is used as a roof window panel.

Images