EP3826838A1

EP3826838A1 - Composite pane comprising a functional element having electrically controllable optical properties with improved edge sealing

Info

Publication number: EP3826838A1
Application number: EP19735351.9A
Authority: EP
Inventors: Marcel Klein; Sebastian SCHURSE
Original assignee: Saint Gobain Glass France SAS; Compagnie de Saint Gobain SA
Current assignee: Saint Gobain Glass France SAS; Compagnie de Saint Gobain SA
Priority date: 2018-07-26
Filing date: 2019-07-08
Publication date: 2021-06-02
Also published as: WO2020020614A1; US20210008842A1; CN110958940A

Abstract

The invention relates to a composite pane (100) comprising a functional element (5) having electrically controllable optical properties, at least comprising in this order - a first pane (1), - a first thermoplastic composite film (3) having at least one plasticiser, - a functional element (5) having a peripheral edge (8), - a barrier film (6) having a cutout (7) into which the functional element (5) is inserted, - a second thermoplastic composite film (4) having at least one plasticiser, - a second pane (2), wherein - the barrier film (6) surrounds the functional element (5) in the manner of a frame and is in direct contact with the peripheral edge (8) of the functional element (5), and - the barrier film (6) contains at most 0.5 wt.% plasticiser and prevents the diffusion of plasticiser through the barrier film (6).

Description

Composite pane with functional element with electrically controllable optical

Properties with improved edge sealing

The invention relates to a composite pane with a functional element with electrically controllable optical properties with improved edge sealing, and in particular to a vehicle pane with a functional element.

In the vehicle and construction sectors, composite panes with electrically controllable functional elements are often used for sun protection or for privacy.

For example, windshields are known in which a sun visor in the form of a functional element with electrically controllable optical properties is integrated. In particular, the transmission or the scattering behavior of electromagnetic radiation in the visible range can be controlled electrically. The functional elements are usually film-like and are laminated into a composite pane or glued to it. In the case of windshields, the driver can control the transmission behavior of the windshield with respect to solar radiation. This eliminates the need for a conventional mechanical sun visor. This allows the weight of the vehicle to be reduced and space is gained in the roof area. In addition, the electrical control of the sun visor is more convenient for the driver than the manual folding down of the mechanical sun visor.

Windshields with such electrically controllable sun visors are known, for example, from WO 2014/086555 A1, DE 102013001334 A1,

DE 102005049081 B3, DE 102005007427 A1 and DE 102007027296 A1. In addition, functional elements are also used for shading vehicle glazing as roof panes, as described for example in EP 2010385 B1.

Due to the local introduction of functional elements, such as controllable sun visors, into the intermediate layer of a composite pane, a local increase in thickness occurs in this area, which can cause tension in the glass of the pane or even breakage of the glass. Such differences in thickness can be compensated for, for example, by using a polyvinyl butyral frame film into which the functional element is inserted. Such a structure is described in EP 2010385 B1. Typical electrically controllable functional elements contain electrochromic layer structures or single particle device (SPD) foils. Further possible functional elements for realizing an electrically controllable sun protection are so-called PDLC functional elements (polymer dispersed liquid crystai). Its active layer contains liquid crystals, which are embedded in a polymer matrix. If no voltage is applied, the liquid crystals are disordered, which leads to a strong scattering of the light passing through the active layer. If a voltage is applied to the surface electrodes, the liquid crystals align in a common direction and the transmission of light through the active layer is increased. The PDLC functional element works less by reducing the overall transmission, but by increasing the scatter to ensure glare protection.

DE 20 2018 102 520 U1 describes a composite pane with a functional element with electrically switchable optical properties and strip-shaped busbars for the electrical contacting of the functional element.

Laminated functional elements and in particular PDLC functional elements often show undesirable signs of aging in the peripheral area, such as brightening and changes in shading. The reason for this is considered to be the diffusion of connections, in particular plasticizers, from the thermoplastic composite films of the composite pane into the active layer of the functional element. Sealing the edge area of the functional element prevents diffusion and provides remedial action, for example according to US 201 10171443 A1, by applying an adhesive tape which closes the open edge of the active layer. However, such an adhesive tape must be placed manually around the open film edge, automation proves to be difficult here. In addition, the adhesive tape, particularly in the case of complex shaping of the functional element, causes wrinkling, which results in an insufficient seal.

WO 2017/157626 A1 relates to a windshield with an electrically switchable functional element inserted as a sun visor in the thermoplastic intermediate layer of the windshield, the thermoplastic intermediate layer being at least partially tinted in the area of the functional element. The functional element is sealed at the edges by means of an adhesive or adhesive tape. As an alternative to sealing the peripheral edge of the functional element by means of an adhesive tape, components of the thermoplastic intermediate layer, in which the functional element is embedded, can also be designed with a low plasticizer according to US 2009/0279004 A1.

US 2005/0227061 A1 proposes the use of thin strips of PET film which are applied to an SPD functional element in the edge regions thereof.

The object of the present invention is therefore to develop an improved composite pane which comprises a functional element with improved edge sealing and high aging resistance, and to provide a method which enables simplified handling and a high degree of automation.

The object of the present invention is achieved by a composite pane according to independent claim 1. Preferred statements emerge from the subclaims.

The invention relates to a composite pane with a functional element with electrically controllable optical properties with an improved edge sealing of the functional element. The composite pane contains at least a first pane, a first thermoplastic compound film, a functional element, a barrier film, a second thermoplastic compound film and a second pane. The thermoplastic composite films each contain at least one plasticizer. The functional element comprises a peripheral edge and is inserted between the first thermoplastic composite film and the second thermoplastic composite film in the layer stack. The peripheral edge of the functional element is surrounded in a frame-like manner by the barrier film, the barrier film being in direct contact with the edge of the functional element. For this purpose, the barrier film has a cutout in which the functional element is inserted. The functional element and the barrier film thus lie in the same plane of the layer stack and touch along their edges, their contact surface being essentially orthogonal to the pane surfaces of the composite pane. The barrier film comprises at most 0.5 percent by weight of a plasticizer and prevents the diffusion of plasticizer through the barrier film. This is particularly advantageous since the structure according to the invention prevents diffusion of plasticizers and other components from the thermoplastic composite films into the active layer of the functional element and the aging resistance of the functional element is thus significantly improved. In addition, in the composite pane according to the invention, a local difference in thickness between the area with the functional element and the surrounding area is at least partially compensated for by the barrier film. According to the invention, the barrier film is not overlapping with the functional element, but rather only in its immediate vicinity adjacent to the circumferential edge of the functional element, whereby this compensation for differences in thickness is possible. The composite pane with functional element therefore not only has improved aging resistance, but also improved durability by minimizing stress and breaking glass. Furthermore, the production of the composite pane is simplified by the layer structure according to the invention, since no further thermoplastic frame film may be necessary to ensure compensation for local differences in thickness.

In a preferred embodiment of the invention, the immediate layer sequence of the composite pane in the area of the functional element and in the vicinity of the functional element consists in this order of the first pane, the first thermoplastic composite film with at least one plasticizer, the functional element with a peripheral edge, which is in the plane of the functional element horizontal barrier film with a cutout in which the functional element is inserted, a second thermoplastic composite film with at least one plasticizer and the second pane. In this sense, the area of the functional element is defined as the area which, after the surface of the functional element has been projected onto the first pane and the second pane, lies between these two projections. The regions of the layer stack which adjoin the peripheral edge of the functional element are designated as being adjacent to the functional element. Such an arrangement is advantageous with regard to a layer stack that is as thin as possible and homogeneous with regard to its thickness profile.

The barrier film is preferably used as a continuous frame-shaped film which has no interruptions within the circumferential frame. Continuous in this sense means that the corresponding barrier film is uninterrupted all around the functional element, that is to say has no interruptions. The frame results from the cutout in the area of the functional element. By means of a continuous through Shaping is to achieve an improved seal. In comparison, quality problems can occur when using individual sections of a barrier film, which are each placed along the edges of the functional element. For example, air pockets can occur in the overlap areas of the individual strip-shaped sections of the barrier films, or the plasticized material of the thermoplastic composite films can penetrate into these areas if there is insufficient overlap. A flat, continuous, frame-like design of the barrier film along the circumferential edge of the functional element is thus advantageous in terms of product quality.

A continuous frame-shaped barrier film is particularly advantageous in connection with the use of pre-bonds made of barrier film and a thermoplastic composite film. The frame-like shape is advantageous with regard to the dimensional stability of the barrier films in the pre-composite. This simplifies the insertion of the frame-shaped barrier film and thus prevents the occurrence of insertion errors, which increases the product quality.

The enumeration of the elements of the stacking sequence reflects the spatial sequence in which the elements are arranged one above the other. The elements are essentially flat and consist of thin layers or plates with a large lateral extent. It goes without saying that the large areas of the respective elements are arranged parallel to one another.

The specification of the sequence does not restrict the chronological sequence. This means that, for example, the inner pane or the outer pane can be started in the production of the stacking sequence. Furthermore, sub-groups can be created before the entire assembly of the stacking sequence.

The controllable functional element typically comprises an active layer between two surface electrodes. The active layer has the controllable optical properties, which can be controlled via the voltage applied to the surface electrodes. The surface electrodes and the active layer are typically arranged essentially parallel to the surfaces of the first disk and the second disk. The surface electrodes are electrically connected to an external voltage source in a manner known per se. The electrical contacting is implemented by means of suitable connecting cables, for example foil conductors, which optionally have so-called busbars bars), for example strips of an electrically conductive material or electrically conductive imprints, are connected to the surface electrodes.

The surface electrodes are preferably designed as transparent, electrically conductive layers. The surface electrodes preferably contain at least one metal, a metal alloy or a transparent conductive oxide (TCO). The surface electrodes can contain, for example, silver, gold, copper, nickel, chromium, tungsten, indium tin oxide (ITO), gallium-doped or aluminum-doped zinc oxide and / or fluorine-doped or antimony-doped tin oxide. The surface electrodes preferably have a thickness of 10 nm to 2 pm, particularly preferably from 20 nm to 1 pm, very particularly preferably from 30 nm to 500 nm.

In addition to the active layer and the surface electrodes, the functional element can have further layers known per se, for example barrier layers, blocker layers, antireflection layers, protective layers and / or smoothing layers.

The functional element is preferably in the form of a multilayer film with two outer carrier films. In such a multilayer film, the surface electrodes and the active layer are arranged between the two carrier films. By outer carrier film is meant here that the carrier films form the two surfaces of the multilayer film. The functional element can thereby be provided as a laminated film which can be processed advantageously. The functional element is advantageously protected from damage, in particular corrosion, by the carrier films. The multilayer film contains, in the order given, at least one carrier film, one surface electrode, one active layer, another surface electrode and another carrier film. The carrier foil carries in particular the surface electrodes and gives a liquid or soft active layer the necessary mechanical stability.

The carrier films preferably contain at least one thermoplastic polymer, particularly preferably low-plasticizer or plasticizer-free polyethylene terephthalate (PET). This is particularly advantageous with regard to the stability of the multilayer film. However, the carrier films can also contain or consist of other low-plasticizer or plasticizer-free polymers, for example ethylene vinyl acetate (EVA), polypropylene, polycarbonate, polymethyl methacrylate, polyacrylate, polyvinyl chloride, polyacetate resin, casting resins, acrylates, fluorinated ethylene propylenes, polyvinyl fluoride and / or ETFE. The fat each carrier film is preferably from 0.1 mm to 1 mm, particularly preferably from 0.1 mm to 0.2 mm. In particular, the carrier films contain or consist of plasticizer-free polyethylene terephthalate.

Typically, the carrier foils each have an electrically conductive coating which faces the active layer and functions as a surface electrode.

In a further advantageous embodiment of a composite pane according to the invention, the functional element is a PDLC functional element (polymer dispersed liquid crystai). The active layer of a PDLC functional element contains liquid crystals which are embedded in a polymer matrix. If no voltage is applied to the surface electrodes, the liquid crystals are disordered, which leads to a strong scattering of the light passing through the active layer. If a voltage is applied to the surface electrodes, the liquid crystals align in a common direction and the transmission of light through the active layer is increased.

In principle, however, it is also possible to use other types of controllable functional elements, for example electrochromic functional elements or SPD functional elements (suspended particle device). The controllable functional elements mentioned and their mode of operation are known per se to the person skilled in the art, so that a detailed description can be dispensed with here.

Functional elements as multilayer films are commercially available. The functional element to be integrated is typically cut out of a multilayer film with larger dimensions in the desired shape and size. This can be done mechanically, for example with a knife. In an advantageous embodiment, the cutting is carried out using a laser. It has been shown that the side edge is more stable in this case than with mechanical cutting. In the case of mechanically cut side edges, there may be a risk of the material retracting, which is visually striking and adversely affects the aesthetics of the pane.

The functional element is connected to the first pane via a region of the first thermoplastic composite film and to the second pane via a region of the second thermoplastic composite film. The first and the second thermoplastic composite film are preferably arranged flat on top of one another, the functional element and the barrier film are inserted between the two composite films. The regions of the thermoplastic composite films overlapping with the functional element then form the regions which connect the functional element to the panes.

The composite pane can be, for example, the windshield or the roof pane of a vehicle or other vehicle glazing, for example a separating pane in a vehicle, preferably in a rail vehicle or a bus. Alternatively, the composite pane can be architectural glazing, for example in an exterior facade of a building, or a partition pane in the interior of a building.

The terms first disc and second disc arbitrarily describe two different discs. In particular, the first pane can be referred to as an outer pane and the second pane as an inner pane.

If the composite pane is provided for separating an interior space from the external environment in a window opening of a vehicle or a building, the pane (second pane) facing the interior (vehicle interior) is referred to as the inside pane in the sense of the invention. The outer pane is the pane facing the external environment (first pane). However, the invention is not restricted to this.

The composite pane according to the invention contains a functional element with electrically controllable optical properties, which is arranged at least in sections between a first thermoplastic composite film and a second thermoplastic composite film. The first and second thermoplastic composite films usually have the same dimensions as the first and the second pane. The functional element is preferably film-like.

The invention is particularly directed to composite panes, the functional element of which is realized by a polymer dispersed liquid crystal (PDLC) film, since such functional elements have a clear aging effect, which must be reduced.

The thickness of the barrier film and the thickness of the functional element preferably deviate from one another by at most 30%, particularly preferably by at most 20%, in particular by at most 15%. This is advantageous with regard to the greatest possible coverage the peripheral edge of the functional element along the edge height. With increasing edge coverage of the functional element by the barrier film, its aging resistance also increases due to the improved edge sealing. However, the inventors have found that for a good result, a complete match between the thicknesses of the functional element and the barrier film and therefore no complete edge covering is necessary. With regard to the use of standardized film thicknesses, which is advantageous in the production process, it is therefore possible to consciously dispense with a complete covering of the edge by the barrier film. Thickness deviations of up to 20% between the functional element and the barrier film have led to good results. Depending on the complexity of the pane geometry and the local bending of the pane at the position of the functional element, an additional frame film can be dispensed with in this case.

The thickness of the barrier film is preferably greater than or equal to the thickness of the functional element.

In one possible embodiment, the thickness of the barrier film and the thickness of the functional element are essentially the same. In this way, a particularly good aging resistance and can be achieved. In addition, there is no need for an additional frame film to compensate for local differences in height, since this height compensation can take place entirely via the barrier film and no tensions arise from differences in height.

The entire peripheral edge of the functional element is preferably in direct contact with the barrier film along its entire height. The barrier film has a thickness that is greater than or equal to the thickness of the functional element. This is advantageous in order to achieve a particularly reliable covering of the open edge of the functional element and thus an optimal aging resistance. At the same time, standardized film thicknesses of the barrier film can still be used, the commercially available barrier film being selected which exceeds the thickness of the functional element and which comes closest. Here too, the maximum thickness deviations of preferably at most 30%, particularly preferably at most 20%, in particular at most 15%, already discussed in this connection, are considered advantageous in order to reduce the internal stresses of the glazing. The barrier film has a thickness of 0.1 mm to 1.0 mm, preferably 0.3 mm to 0.5 mm, particularly preferably 0.40 mm to 0.45 mm. A wide variety of barrier films with different thicknesses are commercially available in these areas. Polyethylene terephthalate films, which are currently available in thicknesses of 0.10 mm, 0.40 mm or 0.45 mm, are only examples here. However, the commercial offer of various films is constantly increasing, so that in the future an increasing selection of materials and film thicknesses can be expected.

Functional elements comprising PDLC multilayer films are commercially available and usually have a total thickness of the PDLC multilayer stack of approximately 100 pm to 500 pm, preferably of 200 pm to 400 pm.

The first thermoplastic composite film, the second thermoplastic composite film and / or the thermoplastic frame film each contain at least one plasticizer. Plasticizers are chemical compounds that make plastics softer, more flexible, more supple and / or more elastic. They shift the thermoelastic range of plastics to lower temperatures, so that the plastics have the desired more elastic properties in the range of the application temperature. Preferred plasticizers are carboxylic acid esters, in particular low-volatile carboxylic acid esters, fats, oils, soft resins and camphor. Other plasticizers are preferably aliphatic diesters of tri or tetraethylene glycol. 3G7, 3G8 or 4G7 are particularly preferably used as plasticizers, the first digit denoting the number of ethylene glycol units and the last digit denoting the number of carbon atoms in the carboxylic acid part of the compound. Thus 3G8 stands for triethylene glycol bis (2-ethylhexanoate), ie for a compound of the formula C ₄ H ₉ CH (CH ₂ CH ₃ ) CO (0CH ₂ CH ₂ ) ₃ 0 ₂ CCH (CH ₂ CH ₃ ) C ₄ H ₉ .

The first thermoplastic composite film, the second thermoplastic composite film and / or the thermoplastic frame film preferably contain at least 3% by weight, preferably at least 5% by weight, particularly preferably at least 20% by weight, even more preferably at least 30% by weight and in particular at least 40% by weight of a plasticizer. The plasticizer preferably contains or consists of triethylene glycol bis (2-ethylhexanoate).

More preferably, the first thermoplastic composite film, the second thermoplastic composite film and / or the thermoplastic frame film contain at least 60% by weight, particularly preferably at least 70% by weight, in particular at least 90% by weight and for example at least 97% by weight of polyvinyl butyral.

The low-plasticizer barrier films are selected in the composite disc according to the invention, with a plasticizer content of less than 0.5% by weight. The barrier film is very particularly preferably plasticizer-free, that is to say without the targeted addition of a plasticizer.

Plasticizer-free plastics are particularly preferred. The barrier films contain or consist of polyethylene terephthalate (PET) or polyvinyl fluoride (PVF) in particular. These materials are available free of plasticizers, which further improves the aging resistance of the functional element compared to the use of low-plastic barrier films.

In a particularly preferred embodiment, the material composition of the barrier film and the thermoplastic composite film differs according to their main components by mass. The inventors were able to observe that with a similar choice of material for the directly touching components, there is a certain diffusion of chemical compounds from the thermoplastic composite film through the barrier film to the open edges of the functional element. This is completely or almost completely prevented by choosing a material for the barrier film which not only differs from that of the thermoplastic composite film in terms of its plasticizer content, but also in its main polymer component.

An embodiment comprising barrier films containing polyethylene terephthalate as the main component in combination with thermoplastic composite films containing polyvinyl butyral as the main component has proven to be particularly advantageous with regard to restricting the diffusion of plasticizers and other chemical compounds.

The thermoplastic composite films and the barrier film can both be introduced as individual film layers in the layer stack of the composite pane, or can be inserted in the form of a pre-composite. Such a pre-composite comprises a plurality of foils to be arranged adjacent in the composite pane. Preliminary composites from two layers of film, For example, a barrier film and a thermoplastic composite film are referred to as bilayers. In the manufacture of the composite pane according to the invention, simplified use is ensured by using pre-bonds (bilayers) made of thermoplastic composite film and barrier film. The barrier film retains its inherent stability even with complex geometries of the cutout in which the functional element is inserted. Furthermore, precise positioning is facilitated and the barrier film does not slip in the layer stack. In addition, electrostatic effects occur when using a single barrier film, which further complicate handling. Masking the open edge of the functional element, as is known from the prior art, is not possible in the case of complex geometries, since the adhesive tape wrinkles.

Within the pre-assembly, the barrier film is in direct contact with the corresponding thermoplastic composite film of the pre-assembly. The preliminary composites according to the invention accordingly have no adhesion promoters, adhesion-improving coatings and / or adhesives. The inventors have found that such bonding is not necessary when using pre-bonds. Further details on the manufacture and structure of the preliminary composites are described in the course of the method according to the invention.

The thickness of the thermoplastic composite films is in each case preferably from 0.2 mm to 2 mm, particularly preferably from 0.3 mm to 1 mm, in particular from 0.3 mm to 0.5 mm, for example 0.38 mm.

The composite pane according to the invention can contain a first thermoplastic composite film and a second thermoplastic composite film or also a plurality of first and / or second thermoplastic composite films. Instead of a first and / or second thermoplastic composite film, there can accordingly also be a two-layer, three-layer or multi-layer stack of thermoplastic composite films and / or further functional films, the individual films having the same or different properties. A thermoplastic composite film can also be formed from sections of different thermoplastic films, the side edges of which adjoin one another.

In an advantageous development of a composite pane according to the invention, the area of the thermoplastic composite films is used to cover the functional element with the first and / or second pane is connected, tinted or colored. The transmission of this range in the visible spectral range is therefore reduced compared to an untinted or colored layer. The tinted / colored area of the intermediate layer thus lowers the transmission of the windshield in the area of the sun visor. In particular, the aesthetic impression of the functional element is improved because the tint leads to a more neutral appearance, which is more pleasant to the viewer.

This tinting or coloring of the composite pane can be achieved by several measures, which can also be combined with one another if necessary. In general, it is possible to manufacture the first and / or the second pane from tinted or colored glass. Furthermore, the first and / or the second thermoplastic composite film, which can optionally also be used in the form of a bilayer with the barrier film, can be tinted or colored. In addition to the first and second thermoplastic composite films, further tinted or colored films can be placed in the layer stack. Foils in which the tinted or colored area is produced by local tinting or dyeing can also be used as the first, second or also further thermoplastic composite films. Such films can be obtained, for example, by coextrusion. Alternatively, an untinted film section and a tinted or colored film section can be put together to form the thermoplastic layer.

The tinted or colored area of the intermediate layer preferably has a transmission in the visible spectral range from 10% to 50%, particularly preferably from 20% to 40%. This gives particularly good results in terms of glare protection and visual appearance.

The tinted or colored area can be homogeneously colored or tinted, that is, have a location-independent transmission. However, the tinting or coloring can also be inhomogeneous, in particular a transmission curve can be realized. In one embodiment, the degree of transmission in the tinted or colored area decreases at least in sections with increasing distance from the upper edge. In this way, sharp edges of the tinted or colored area can be avoided, so that the transition from a PDLC functional element used as a sun visor to the transparent area of the windshield is gradual, which looks more aesthetically pleasing. In an advantageous embodiment, the second pane corresponds to the outer pane and the area of the second thermoplastic composite film, that is to say the area between the functional element and the outer pane is tinted. This creates a particularly aesthetic impression when viewed from above on the outer pane. The area of the first thermoplastic composite film between the functional element and the inner pane (first pane) can optionally also be colored or tinted.

In a preferred embodiment of the composite pane according to the invention, the first and the second thermoplastic composite film are tinted. Between the second pane (here: outer pane) and the second thermoplastic composite film, a carrier film with an infrared-reflecting coating, followed by another thermoplastic composite film, is placed in the layer stack. After lamination of the layer stack, the carrier film with infrared-reflecting coating is connected to the functional element via the second thermoplastic composite film, while the connection to the second pane is made via the further thermoplastic composite film. The first thermoplastic composite film ensures a connection to the first pane either directly or optionally with the interposition of further film components. Such a construction is advantageous, for example, as a roof window of a motor vehicle, since the infrared-reflecting coating reduces the undesired heating of the vehicle interior by solar radiation. The tinted thermoplastic composite films, in addition to the already mentioned attractive design of the composite pane, also contribute to reducing the solar radiation. In a further advantageous variant of this exemplary embodiment, a polymer-free metal-free film is used instead of a carrier film with an infrared-reflecting coating, which film itself has infrared-reflecting properties. Such polymer films without metallic components are commercially available. The infrared reflecting effect comes about through a sequence of a large number of polymer layers, at the interfaces of which partial reflection takes place.

In the context of the invention, electrically controllable optical properties are understood to mean those properties which can be steplessly controlled, but equally also those which can be switched between two or more discrete states.

The electrical control of the sun visor or the switchable vehicle roof glazing takes place, for example, by means of switches, rotary or slide controls, which are integrated in the fittings of the vehicle. But there can also be a button for regulating the Sun visor can be integrated in the windshield or in the roof surface, for example a capacitive button. Alternatively or additionally, the sun visor can be controlled by non-contact methods, for example by recognizing gestures, or depending on the state of the pupil or eyelid ascertained by a camera and suitable evaluation electronics. Alternatively or additionally, the sun visor can be controlled by sensors which detect the incidence of light on the pane.

The composite pane with an electrically controllable functional element can advantageously be designed as a windshield or roof pane with an electrically controllable sun visor.

A windshield has an upper edge and a lower edge and two side edges running between the upper edge and lower edge. The top edge is the edge which is intended to point upwards in the installed position. The lower edge is the edge that is intended to point downwards in the installed position. The top edge is often referred to as the roof edge and the bottom edge as the engine edge.

A motor vehicle roof window has a front edge which points in the direction of the windshield and a rear edge which points in the direction of the vehicle rear window. The remaining edges of the roof window are the side edges. The side edges run between the front edge and the rear edge of the pane.

Windshields have a central field of vision, the optical quality of which places high demands. The central field of vision must have high light transmission (typically greater than 70%). Said central field of view is, in particular, that field of vision that is known by the person skilled in the art as field of vision B, field of view B or zone B. The field of vision B and its technical requirements are defined in control no.43 of the United Nations Economic Commission for Europe (UN / ECE) (ECE-R43, "Uniform conditions for the approval of safety glazing materials and their installation in vehicles"). Field of view B is defined there in Appendix 18.

The functional element is advantageously arranged in a windshield above the central field of view (field of view B). This means that the functional element in the area between the central field of vision and the top edge of the windshield is arranged. The functional element does not have to cover the entire area, but is completely positioned within this area and does not protrude into the central field of vision. In other words, the functional element has a smaller distance from the upper edge of the windshield than the central field of vision. Thus, the transmission of the central field of view is not affected by the functional element, which is positioned at a similar location to a classic mechanical sun visor when folded down.

The windshield is preferably provided for a motor vehicle, particularly preferably for a passenger car.

In a preferred embodiment of a windshield according to the invention, the lower edges of the functional element and the tinted area of the intermediate layer (s) are adapted to the shape of the upper edge of the windshield, which results in a more visually appealing appearance. Since the upper edge of a windshield is typically curved, in particular concavely curved, the lower edge of the functional element and of the tinted area is also preferably curved. The lower edges of the functional element are particularly preferably formed essentially parallel to the upper edge of the windshield. But it is also possible to build the sun visor from two straight halves, which are arranged at an angle to each other and approximate the shape of the upper edge in a V-shape.

In one embodiment of the invention, the functional element is divided into segments by insulation lines. The insulation lines are in particular introduced into the surface electrodes, so that the segments of the surface electrode are electrically insulated from one another. The individual segments are independently connected to the voltage source so that they can be controlled separately. Different areas of the sun visor can be switched independently. The insulation lines and the segments are particularly preferably arranged horizontally in the installed position. This allows the user to control the height of the sun visor. The term “horizontal” is to be interpreted broadly here and denotes a direction of propagation that runs between the side edges of the windshield in the case of a windshield. The insulation lines do not necessarily have to be straight, but can also be slightly curved, in particular adapted to a possible bending of the upper edge of the windshield, in particular essentially parallel to the top edge of the windshield. Vertical insulation lines are of course also conceivable.

The insulation lines have, for example, a width of 5 pm to 500 pm, in particular 20 pm to 200 pm. The width of the segments, that is to say the distance between adjacent insulation lines, can be suitably selected by the person skilled in the art in accordance with the requirements in the individual case.

The insulation lines can be introduced by laser ablation, mechanical cutting or etching during the production of the functional element. Already laminated multilayer films can also be subsequently segmented using laser ablation.

Functional elements in roof panels are usually switched as a complete surface. However, as described for the windshield, the roof pane according to the invention can also be divided into individually switchable segments by insulation lines.

The top edge and the side edges or all side edges of the functional element are preferably covered by an opaque cover print or by an outer frame when looking through the composite pane. Windshields and roof panes typically have an all-round peripheral cover print made of an opaque enamel, which is used in particular to protect and visually hide the adhesive used to install the pane from UV radiation. This peripheral masking print is preferably used to cover the top edge and the side edge of the functional element as well as the required electrical connections. The functional element is then advantageously integrated into the appearance of the pane. Only in the case of sun visors can the lower edge potentially be recognized by the viewer. Both the outer pane and the inner pane preferably have a covering pressure, so that the view in the edge region is prevented from both sides.

The functional element can also have cutouts or holes, for example in the area of so-called sensor windows or camera windows. These areas are intended to be equipped with sensors or cameras, the function of which would be impaired by a controllable functional element in the beam path, for example rain sensors. It is also possible to use the sun visor with at least two of them to realize separate functional elements, there being a distance between the functional elements which provides a space for sensor or camera windows.

The functional element (or the entirety of the functional elements in the case described above of several functional elements) is preferably arranged over the entire width of the composite pane, minus an edge region with a width of, for example, 2 mm to 20 mm. The functional element is encapsulated within the intermediate layer and protected against contact with the surrounding atmosphere and corrosion.

The first and the second pane are preferably made from glass, particularly preferably from soda-lime glass, as is customary for window panes. However, the panes can also be made from other types of glass, for example quartz glass, borosilicate glass or alumino-sililate glass, or from rigid, clear plastics, for example polycarbonate or polymethyl methacrylate. The lenses can be clear, or tinted or colored. Windshields must have sufficient light transmission in the central viewing area, preferably at least 70% in the main viewing area A according to ECE-R43.

The first pane, the second pane and / or the intermediate layer can have further suitable coatings known per se, for example anti-reflective coatings, non-stick coatings, anti-scratch coatings, photocatalytic coatings or sun protection coatings or low-E coatings).

The thickness of the first and the second pane can vary widely and can thus be adapted to the requirements in the individual case. The first and the second disk preferably have thicknesses of 0.5 mm to 5 mm, particularly preferably of 1 mm to 3 mm.

The invention further comprises a method for producing a composite pane with a functional element. A first thermoplastic composite film is arranged flat on a first pane and a functional element with a barrier film surrounding the functional element in the form of a frame is arranged on the first thermoplastic composite film. The barrier film borders directly on the peripheral edge of the functional element. Barrier film and functional element can be applied in any order one after the other or simultaneously. On the functional element and the A second thermoplastic composite film and finally a second pane are placed on the barrier film. The layer stack is connected to a composite disc by autoclaving.

The method according to the invention provides a composite pane with a functional element with high aging resistance. The barrier film surrounds the functional element in a frame shape and is in direct contact with the peripheral edge. The peripheral edge of the functional element is thus sealed by means of the barrier film, so that plasticizers from the thermoplastic composite films do not enter the active layer of the functional element. The barrier film itself contains at most 0.5% by weight of plasticizer and prevents the diffusion of plasticizer through the barrier film. In addition, with a corresponding thickness of the barrier film, a thermoplastic frame film can be dispensed with, which saves one process step in the method according to the invention.

In a particularly preferred embodiment of the method according to the invention, the barrier film is inserted into the layer stack as a pre-composite together with the first thermoplastic composite film or the second thermoplastic composite film.

The method according to the invention enables simple handling by using the preliminary composite (bilayer) made of a thermoplastic composite foil and the barrier foil. Because these foils are used as bilayers, the barrier foil retains its own stability. Particularly in the case of large-area functional elements, the size of the barrier film, which is adapted to the functional element, represents an unstable frame of small width, which, however, has to be fitted precisely in order to prevent slipping in the layer stack. This problem of stability is avoided by the method according to the invention. In addition, electrostatic effects occur when using a single barrier film, which further complicate handling. By using bilayers according to the invention, the barrier film can be brought into any shape. This also enables a rounded or round edge design of the functional element. In contrast, masking the open edge of the functional element, as is known from the prior art, is not possible in the case of round geometries, since the adhesive tape is wrinkled. By means of the method according to the invention, inclusions of air bubbles and thereby resulting optical disturbances or impairments avoided, since the barrier films lie evenly and on the peripheral edge of the functional element.

In one possible embodiment, the first thermoplastic composite film is placed on the first pane and the functional element is placed thereon. The barrier film is then placed on the functional element in the form of a pre-composite of barrier film and second composite film such that the barrier film surrounds the peripheral edge of the functional element. Then, if provided, any further layers of the layer stack and finally the second disc are placed on top. As described, the functional element can first be placed on the first composite film and then the barrier film with the second composite film can be placed on the already aligned functional element as a bilayer, but it is also possible, conversely, to first place a bilayer made of composite film and barrier film on the pane and to place the functional element in the cutout of the barrier film. The order of these steps can be chosen arbitrarily.

The preliminary composite according to the invention has no adhesion promoters, adhesion-improving coatings and / or adhesives. This applies to all of the film surfaces of the preliminary composite. There is no adhesion promoter between the barrier films and the associated thermoplastic composite film in the bilayer, nor between the barrier film and the functional element. This lack of an adhesion promoter is a distinguishing feature from structures known from the prior art, in which a fixation is necessary in order to prevent the barrier film from slipping when the layer stack is folded together. In the prior art there is also the teaching that in order to produce a sufficient diffusion barrier for plasticizers, the sealing elements must be glued. The inventors have found that, surprisingly, this is not necessary and that an excellent diffusion barrier for plasticizers can be obtained by means of the method according to the invention even without gluing. Diffusion of plasticizers and other chemical compounds from the thermoplastic composite films into the active layer of the functional element can thus be effectively prevented and undesired clarification of the edge region of the functional element by plasticizers can be prevented. The use of a bilayer in accordance with the method according to the invention also results in a low susceptibility to errors in the production process, which enables a high degree of automation. The method according to the invention thus makes it more resistant to aging Composite pane with functional element accessible with significantly reduced production costs.

The pre-composite of one of the thermoplastic composite foils and the barrier foil is produced before the individual layers of the composite pane are put together. The barrier film is preferably connected to one of the thermoplastic composite films by heating to form a preliminary bond. The barrier film and the thermoplastic film, which are to be formed into a preliminary composite, are preferably heated and pressed together. This application of pressure when heated creates a stable pre-bond that does not come off even when the foils cool down. The steps of heating and compressing the foils can be carried out one after the other, for example by passing the barrier foil and the thermoplastic foil together through a heating register and then pressing them together by a pair of rollers. In a particularly preferred embodiment, a heated pair of rollers is used which presses the barrier film and the thermoplastic composite film together and connects them in one step to form a pre-composite. The use of a pair of rollers for connecting the foils is particularly advantageous since air pockets between the foil components are reliably removed. The pre-composite produced from a barrier film and a thermoplastic composite film can be wound up on a roll and can thus be produced and stored in advance as desired.

It has proven to be advantageous to heat the barrier film and / or the thermoplastic composite film to a temperature of from 35 ° C. to 75 ° C., preferably from 35 ° C. to 60 ° C., particularly preferably from 40 ° C. to 50 ° C. to press them flatly together under pressure to form a preliminary bond. Good adhesion of the films to one another can be found within these temperature ranges. The barrier film and the thermoplastic composite film can both be heated to different temperatures. These are preferably heated to the same temperature. In a particularly advantageous embodiment, the barrier film and the thermoplastic composite film are each unrolled from a roll, passed through a pair of rolls at a temperature of 45 ° C. and pressed flatly with one another and rolled up on a roll as a pre-bond.

The preliminary composite is preferably first created from a thermoplastic composite film arranged essentially congruently and a barrier film. The barrier film of the preliminary composite is then removed in at least one cutout. In this excerpt the functional element is placed when the layer stack is folded. By making a cutout in the barrier film, an inner edge of the barrier film is created along the cutout. The size of the cutout is dimensioned so that the barrier film surrounds the functional element in the form of a mat. The inner edge of the barrier film and the peripheral edge of the functional element are in direct contact. The barrier film represents a continuous, uninterrupted frame. This is advantageous with regard to a secure sealing of the functional element. When using pre-connections, the frame-shaped barrier film is particularly easy to position. The barrier films are therefore only present in the edge area of the functional element, where sealing of the open edges of the functional element is necessary. Functional element and barrier film show no overlap. This is advantageous since the functional element generally has carrier films as outer layers, which often consist of PET. If PET is also selected for the barrier films, the two PET films would not show any adhesion to one another, so that there is an increased risk of optical errors and air pockets. In this respect, it is advantageous that the functional element and the barrier film show no overlap, since the choice of material for the barrier film is not restricted in this way. These statements also apply to the product, and the statements made for the product also apply to the claimed process.

In a preferred embodiment of the method according to the invention, no thermoplastic frame film is inserted into the layer stack, since the barrier film already takes over the thickness-compensating function of the frame film.

The electrical contacting of the surface electrodes of the functional element is preferably carried out before the laminated pane is laminated.

Any existing prints, for example opaque cover prints or printed busbars for electrical contacting of the functional element, are preferably applied using the screen printing process.

The lamination is preferably carried out under the action of heat, vacuum and / or pressure. Processes known per se for lamination can be used, for example autoclave processes, vacuum bag processes, vacuum ring processes, calendering processes, vacuum laminators or combinations thereof. The method according to the invention enables a composite pane according to the invention to be produced which has an improved sealing of the peripheral edge without the need to bond the barrier films to the adjacent film components (thermoplastic composite film, other barrier film) or to the functional element. This lack of adhesives or other point fixation of the barrier films can be seen from the composite pane.

The statements already made in the description of the method according to the invention with regard to the composite pane resulting from the method naturally also apply to the pane itself and vice versa.

The invention further comprises the use of a composite pane according to the invention with electrically controllable functional elements as inner glazing or outer glazing in a vehicle or in a building, the electrically controllable functional element being used as sun protection or as privacy protection.

The invention further comprises the use of a composite pane according to the invention as a windshield or roof pane of a vehicle, the electrically controllable functional element being used as a sun visor.

A great advantage of the invention in the case of composite windows as a windshield is that a classic mechanically foldable sun visor mounted on the vehicle roof can be dispensed with.

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 in no way limits the invention. Show it:

Figure 1 a shows a cross section of a pre-composite of barrier film and thermoplastic

Composite film during film cutting,

1b shows a layer stack of an embodiment of the invention

Composite pane before lamination of the pane,

2a shows a plan view of an embodiment of the composite pane according to the invention, FIG. 2b shows a cross section through the composite pane from FIG. 2a along the section line AA, FIG. 2c shows an enlarged representation of the area Z from FIG. 2b,

Figure 3a is a plan view of a further embodiment of an inventive

Composite pane as roof pane with functional element,

FIG. 3b shows a cross section through the composite pane from FIG. 5a along the section line B

B ',

Figure 4a is a plan view of a further embodiment of an inventive

Composite windshield with sun visor,

FIG. 4b shows a cross section through the composite pane from FIG. 5a along the section line B

B ',

Figure 5 shows an embodiment of the inventive method using a

Flowchart.

FIG. 1 a shows a pre-composite 9 according to the invention comprising a thermoplastic composite film 3 or 4 and a barrier film 6 and the processing steps for cutting the barrier film 6, shown as states A to C. This can be a composite 9 of the first thermoplastic composite film 3 act the barrier film 6, or a composite 9 of the second thermoplastic composite film 4 with the second barrier film 6. The pre-composite 9 according to state A) in Figure 1 a was produced by a thermoplastic composite film 3 or 4 together with a barrier film 6 through a heated roller pair with a temperature of 45 ° C and a speed of 4 m / min. The rollers press the foils together under heating, which combine to form a pre-bond. The thermoplastic composite film 3 or 4 consists of 78% by weight of polyvinyl butyral (PVB) and 20% by weight of triethylene glycol bis (2-ethylhexanoate) as a plasticizer and each has a thickness of 0.38 mm, while the barrier film 6 consists essentially of polyethylene terephthalate (PET) and is 400 pm thick. The barrier film 6 consists here, for example, essentially of PET, that is to say at least 97% by weight. The barrier film 6 contains less than 0.5% by weight of plasticizer and is preferably plasticizer-free. The barrier film 6 is suitable for decisively reducing or preventing the diffusion of plasticizer from the thermoplastic composite films 3, 4. In such a pre-assembly 9, cuts 18 are made in the barrier film 6 of the pre-assembly 9 by means of a cutting tool 17. The depth of cut is chosen so that the thermoplastic composite film 3 or 4 remains essentially undamaged. The cuts 18 made in the barrier film 6 produce a cutout 7 in the surface of the barrier film 6. The barrier film only remains in the form of a peripheral frame in the edge region of the later composite pane. At the point where the cuts 18 were made results an inner edge 22 of the barrier film. Suitable cutting tools 17 are known to the person skilled in the art. For example, a plotter equipped with a cutting blade has proven to be very well suited. However, other methods can also be used, such as laser cutting. The barrier film 6 is removed in the area of the cutout 7. This is possible by lifting the barrier film 6 to be detached at the edge of a cut 18. Starting from such a raised corner, the areas of the barrier film 7 to be removed are pulled off. This can be done with moderate effort and without damaging the foils. The inner edge 22 of the barrier film 6 extends, in relation to the outer edge of the future composite pane, set back inward in the direction of the center of the surface of the barrier film 6. The inner edge 22 runs all the way round and forms a passe-partout into which a functional element can be inserted. The amount by which the inner edge 22 is set back in the direction of the center of the pane in relation to the later outer edge of the composite pane can be variable or constant along the circumferential edge. This variability is made possible above all by the use of a pre-assembly, which enables the foils to be positioned much more precisely in the layer stack. A preliminary composite 9 is formed from a continuous thermoplastic composite film 3 or 4 and a frame-shaped barrier film 6, which is only present at the locations of the preliminary bond where it is required to seal the functional element (see C) in FIG. 1 a). A single barrier film 6 frame-shaped blank has only a low dimensional stability, so that it cannot be handled mechanically and can hardly be handled manually. By using a bilayer (pre-composite 9) according to the invention, the barrier film 6 can be cut in any geometries without restrictions. The stability and manageability of the arrangement is always ensured by the thermoplastic composite film 3 or 4. Accordingly, the use of bilayers is decisive for the automation of the process and the variable design of the functional element.

FIG. 1 b shows a layer stack for producing the composite pane according to the invention using the pre-composite according to FIG. 1 a. The addition signs located between the layers of the layer stack indicate the layer sequence in which the components are arranged one on top of the other. A first thermoplastic composite film 3 is placed on a first pane 1 made of clear soda-lime glass with a thickness of 1.6 mm. The first pane 1 according to FIG. 1 b represents the inner pane of the windshield of a motor vehicle. A functional element 5 is placed on the first thermoplastic composite film 3. The functional element is designed as a PDLC element with a thickness of 400 pm. A bilayer (preliminary composite 9 1 a) applied from a second thermoplastic composite film 4 and a barrier film 6, which points with the barrier film 4 in the direction of the functional element 5. The dimensions of the barrier film 6 and the functional element 5 are coordinated with one another such that the peripheral edge 8 of the functional element 5 is enclosed in a frame-like manner by the inner edge 22 of the barrier film 6. The inner edge 22 of the barrier film 6 and the peripheral edge 8 of the functional element 5 are in direct contact after the layer stack has been folded and autoclaved to form a composite pane. The barrier film 6 has a thickness of 400 μm and thus completely covers the edge 8 of the functional element. Since the functional element and the barrier film 6 have essentially the same thickness (400 μm), there is not only good edge sealing of the functional element 5, but also good thickness compensation over the barrier film 6. A second pane 2 is placed over the second thermoplastic composite film 4 that completes the layer stack. The second pane 2 has a thickness of 2.1 mm and also consists, for example, of a clear soda-lime glass. In this case, the second pane 2 represents the outer pane of a windshield and is bent congruently with the first pane.

The barrier film 6 is cut according to FIG. 1 a so that its dimensions are suitable according to FIG. 1 b to encompass the peripheral edge 8 of the functional element 5. Any other films, for example functional films or colored films, can be arranged between the first thermoplastic composite film 3 and the first pane 1 or between the second thermoplastic composite film 4 and the second pane 2. The preliminary assembly 9 remains in the vicinity of the functional element 5 with an immediate contact between the functional element 5 and the barrier film 6 even when the layer stack is expanded. Such a layer stack can be collapsed by machine. The use of pre-composites thus represents a significant simplification with regard to the manufacturing process of the composite pane. As an alternative to the composite pane described in FIG.

FIG. 2a shows an embodiment of a composite pane 100 according to the invention comprising a first pane 1, a second pane 2, a first thermoplastic composite film 3, a second thermoplastic composite film 4, a barrier layer 6 and a functional element 5. FIG. 2b shows a cross section of the composite pane according to FIG 2a shown along the section line AA. The area Z from FIG. 2b is enlarged in FIG. 2c. The Composite pane 100 can be arranged, for example, as architectural glazing in the frame of a window with further panes for insulating glazing. The first and the second pane 1, 2 consist of clear soda-lime glass, each with a thickness of 2.0 mm. The first pane 1 and the second pane 2 are connected to one another via the first thermoplastic composite film 3 and the second thermoplastic composite film 4. A functional element 5 is inserted between the first thermoplastic composite film 3 and the second thermoplastic composite film 4, which is also connected to the panes 1, 2 via the thermoplastic composite films 3, 4. A barrier film 6 is arranged along the peripheral edge 8 of the functional element and surrounds the peripheral edge 8. Since the peripheral edge 8 of the functional element 5 is completely enclosed by the barrier film 6, the composite pane 100 with the functional element 5 shows no or only a barely perceptible brightening in the edge region of the functional element 5 in aging tests. According to the invention, a diffusion of the plasticizer from the thermoplastic composite films 3, 4 in the functional element 5 and an accompanying degradation of the functional element 5 is avoided. Furthermore, the barrier film 6 serves to compensate for the thickness between the pane area with functional element 5 and the pane area without functional element 5. Accordingly, an additional thermoplastic frame film is not required.

The functional element 5 can be controlled in its optical properties by applying an electrical voltage. The electrical leads are not shown for the sake of simplicity.

The controllable functional element 5 is, for example, a PDLC multilayer film, consisting of an active layer 11 between two surface electrodes 12, 13 and two carrier films 14, 15. The active layer 11 contains a polymer matrix with liquid crystals dispersed therein, which depend on the align the surface electrodes applied electrical voltage, whereby the optical properties can be controlled. The carrier films 14, 15 consist of PET and have a thickness of, for example, 180 μm. The carrier foils 14, 15 are provided with a coating of ITO facing the active layer 11 with a thickness of approximately 100 nm, which form the surface electrodes 12, 13. The surface electrodes 12, 13 can be connected to a voltage source via busbars, not shown (for example formed by a silver-containing screen print) and connecting cables, not shown. The thermoplastic composite films 3, 4 each comprise a thermoplastic film with a thickness of 0.38 mm and consist, for example, of 78% by weight of polyvinyl butyral (PVB) and 20% by weight of triethylene glycol bis (2-ethylhexanoate) as a plasticizer.

The barrier film 6 consists here, for example, essentially of PET, that is to say at least 97% by weight. The barrier film 6 contains less than 0.5% by weight of plasticizer and is suitable for preventing the diffusion of plasticizer from the thermoplastic composite layers 3, 4 into the functional layer 5 via the peripheral edge 8.

The barrier film 6 has a thickness of 450 μm, while the functional element has a thickness of 400 μm. Since the thickness of the barrier film 6 exceeds the thickness of the functional element 5, the inner edge 22 of the barrier film completely covers the peripheral edge of the functional element.

The barrier film 6 is in direct contact with the functional element 5, in the present case through direct contact with the open cross section of the functional element 5 along the circumferential edge 8. The barrier film 6 shows no overlap in the form of a contact of the film surfaces, but instead is made possible by the direct contacting of the side edges targeted selective edge sealing. In this sense, the film surfaces are the surfaces of the films that run essentially parallel to the panes 1, 2, while the film edges show an essentially orthogonal course to the panes 1, 2. In direct contact here means that no further components or chemical compounds, such as adhesives, are arranged between the barrier film 6 and the functional element 5. According to the prior art, the use of adhesive bonds prevents the blocking films from slipping during assembly. According to the invention, an adhesive connection is not necessary and is not desired. Slipping of the barrier films is achieved by using the pre-composite 9, which comprises the barrier film 6 and one of the thermoplastic composite films 3 or 4. The embodiment of the invention described in FIGS. 2a, 2b and 2c contains a pre-composite 6 produced according to FIG. 1 a. The use of pre-composites not only ensures a displacement of the barrier film in the layer stack, but also facilitates the folding of the layer stack. At the same time, inclusions of air bubbles and the resulting optical disturbances or impairments are avoided, since the barrier film 6 lies evenly on the peripheral edge of the functional element 5. The The barrier film 6 according to the invention is firmly fixed in the region of the peripheral edge 8 of the functional element 5 by the internal pressure in the finished laminated composite pane 100 and pressed onto the adjacent film components, as a result of which a hermetic seal takes place even without the use of adhesives. This was unexpected and surprising for the person skilled in the art.

FIG. 3a shows a top view of an embodiment of a composite pane 100 according to the invention as a roof pane of a motor vehicle. FIG. 3b shows a cross section of the roof pane according to FIG. 3a along the section line BB '. The roof pane comprises a first pane 1, a second pane 2, a first thermoplastic composite film 3, a second thermoplastic compound film 4, a barrier layer 6 and a functional element 5. The first and the second pane 1, 2 are bent congruently to one another. The second pane 2 represents the outer pane of the glazing, that is to say it is oriented towards the vehicle surroundings, while the first pane 1 is the inner pane of the composite pane and faces the vehicle interior. The second pane 2 consists of clear soda-lime glass with a thickness of 2.1 mm. The first pane 1 consists of soda-lime glass with a thickness of 1.6 mm and is tinted gray. The tinted inner glass contributes to the attractive appearance of the window, also for the vehicle occupants when looking through the roof window. The first pane 1 and the second pane 2 are connected to one another via the first thermoplastic compound film 3, the second thermoplastic compound film 4 and a further thermoplastic compound film 19. A functional element 5 is inserted between the first thermoplastic composite film 3 and the second thermoplastic composite film 4, which is also connected to the panes 1, 2 via the thermoplastic composite films 3, 4. A first barrier film 6, which surrounds the circumferential edge 8, is arranged along the circumferential edge 8 of the functional element. For this purpose, the barrier film 6 lies directly against the circumferential edge 8 of the functional element 5. As a result, the peripheral edge 8 of the functional element 5 is completely closed and sealed by the barrier film 6. In aging tests, the composite pane 100 with functional element 5 shows no or only a barely perceptible brightening in the edge region of the functional element 5. According to the invention, diffusion of the plasticizer from the thermoplastic composite films 3a, 4a into the functional element 5 and a related degradation of the functional element 5 are avoided. The first thermoplastic composite film 3 and the second thermoplastic composite film 4 are tinted gray in order to make the appearance of the pane appealing. The further thermoplastic composite film 19 is colorless and is attached adjacent to the outer pane (second pane 2). The further one Thermoplastic composite film 19 serves to incorporate a further carrier film 20 with an infrared reflecting coating 21 in the layer stack. The further carrier film 20 is a PET film with a thickness of 50 μm, which is attached between the further thermoplastic composite film 19 and the second thermoplastic composite film 4. The infrared-reflecting coating 21 is oriented in the direction of the second pane 2 (outer pane) and serves to reduce heating of the passenger compartment by solar radiation.

The functional element 5 can be controlled in its optical properties by applying an electrical voltage. The electrical leads are not shown for the sake of simplicity. The controllable functional element 5 is, for example, a PDLC multilayer film, consisting of an active layer 11 between two surface electrodes 12, 13 and two carrier films 14, 15. The further structure of the functional element corresponds to that described in FIGS. 2a-2c.

The chemical composition and the layer thickness of the thermoplastic composite films 3, 4 and the barrier film 6 correspond to the dimensions described in FIGS. 2a-2c. The barrier film 6 also ensures a thickness compensation between the areas with and without functional element 5, so that an additional thermoplastic frame film is therefore not required.

The edge area of the roof pane is covered by a circumferential black print 10 (circumferential peripheral cover print), which is applied at least on the inside of the outer pane. The black printing is formed by printing an opaque enamel on the interior surfaces (facing the interior of the vehicle in the installed position) of the second pane 2. A black print 10 can optionally also be applied to the inside of the first pane 1. The circumferential edge 8 of the functional element 5 lies in the area of the black print 10, so that it cannot be seen from the outside when the roof pane is viewed. The distance between the functional element 5 and the circumferential edge of the roof pane is thus smaller than the width of the black print 10. The electrical connections (not shown) are also expediently attached in the area of the black print 10 and thus hidden.

The barrier film 6 is in direct contact with the functional element 5, in the present case in flat contact with the surfaces of the carrier films 14, 15, and in addition thereto Direct contact to the open cross section of the functional element 5 along the circumferential edge 8. Also according to the exemplary embodiment in FIGS. 3a and 3b, no adhesive or other adhesion-promoting substances are used, but rather the barrier film 6 as a pre-composite 9 according to FIGS. 1a and 1b with one of the thermoplastic Composite films 3, 4 used. The barrier film 6 according to the invention in the region of the peripheral edge 8 of the functional element 5 is firmly fixed there by the internal pressure in the finished laminated composite pane 100 and pressed onto the adjacent film components, as a result of which a hermetic seal takes place even without the use of adhesives. This was unexpected and surprising for the person skilled in the art.

FIG. 4a shows a top view of a further embodiment of a composite pane 100 according to the invention as a windshield with an electrically controllable sun visor. The PDLC functional element 5 is divided into six strip-like segments by horizontal insulation lines 16. The insulation lines 16 have, for example, a width of 40 pm to 80 pm and a mutual distance of 3.5 cm. They were introduced into the prefabricated multilayer film using a laser. The insulation lines 16 in particular separate the electrodes 12, 13 into strips which are insulated from one another and each have a separate electrical connection. The segments can be switched independently of each other. The thinner the insulation lines 16, the less conspicuous they are. Even thinner insulation lines 16 can be realized by means of etching processes.

The height of the darkened functional element 5 can be set by the segmentation. Depending on the position of the sun, the driver can darken the entire sun visor or only a part of it. The figure indicates that the upper half of the sun visor is darkened and the lower half is transparent.

In a particularly comfortable embodiment, the functional element 5 is controlled by a capacitive button arranged in the region of the functional element, the driver determining the degree of darkening by the location at which he touches the pane.

The windshield according to FIGS. 4a and 4b comprises a trapezoidal composite pane 100 with a first pane 1 as the inner pane and a second pane 2 as the outer pane, which are connected to one another via two thermoplastic composite films 3, 4. The second disc 2 has a thickness of 2.1 mm and consists of a green colored soda-lime glass. The first pane 1 has a thickness of 1.6 mm and consists of a clear soda-lime glass. The windshield has an upper edge D facing the roof in the installed position and a lower edge M facing the engine compartment in the installed position. The cross section of the composite pane 100 is shown in detail in FIG. 4b. This essentially corresponds to the structure according to FIG. 3b. Deviating from this, however, a further thermoplastic composite film 19 is inserted outside the area in which the functional element 5 is inserted into the composite pane 100. This further composite film 19 is laterally adjacent to the barrier film 6, which serves to seal the functional element. In this case, the thickness compensation between areas with and without functional element takes place via the barrier film 6 and the further thermoplastic composite film 19 arranged adjacent to it.

The sun visor is formed by a commercially available multi-layer PDLC film as functional element 5, which is embedded in the thermoplastic composite films. For example, the height of the sun visor is 21 cm. The first thermoplastic composite film 3 is connected to the first pane 1, the second thermoplastic composite film 4 is connected to the second pane 2. In the area of the peripheral edge 8 of the functional element 5, a barrier film 6 is inserted into the layer stack, which surrounds the edge 8 and seals the functional element 5. The barrier film 6 is used as a pre-composite 9 with the second thermoplastic composite film 4.

The second thermoplastic composite film 4 has a tinted area which is arranged between the functional element 5 and the second pane 2 (outer pane). The light transmission of the windshield is thereby additionally reduced in the area of the functional element 5 and the milky appearance of the PDLC functional element 5 is softened in the diffuse state. This makes the aesthetics of the windshield much more appealing. The second thermoplastic composite film 4 has, for example, an average light transmission of 30% in the tinted area, with which good results are achieved. The area can be tinted homogeneously. However, it is often more visually appealing if the tint becomes less in the direction of the lower edge of the functional element 5, so that the tinted and the untinted area merge smoothly into one another.

The lower edge of the tinted area and the lower edge of the PDLC functional element 5 can be arranged flush with one another. However, this is not necessarily the case. It is also possible for the tinted area to protrude beyond the functional element 5 or that, conversely, the functional element 5 protrudes beyond the tinted area. In the latter case, the entire functional element 5 would not be connected to the second pane 2 via the tinted area.

The controllable functional element 5 is a multilayer film, analogous to the structure shown in FIG. 2c, consisting of an active layer 11 between two surface electrodes 12, 13 and two carrier films 14, 15. The active layer 11 contains a polymer matrix with liquid crystals dispersed therein align themselves as a function of the electrical voltage applied to the surface electrodes, as a result of which the optical properties can be regulated. The carrier films 14, 15 consist of PET and have a thickness of, for example, 0.125 mm. The carrier foils 14, 15 are provided with a coating of ITO facing the active layer 11 with a thickness of approximately 100 nm, which form the electrodes 12, 13. The electrodes 12, 13 can be connected to the on-board electrical system via busbars, not shown (for example formed by a silver-containing screen print) and connecting cables, not shown.

For the thermoplastic composite films 3, 4, 19 according to FIGS. 1 to 4, a so-called “high flow PVB” can preferably be used, which has a stronger flow behavior than standard PVB films. The layers flow more strongly around the barrier film 6 and the functional element 5, as a result of which a more homogeneous optical impression is created and the transition from the functional element 5 to the composite films is less noticeable. The “High Flow PVB” can be used for all or only for one or more of the thermoplastic composite films 3, 4, 19.

Figure 5 shows an embodiment of the inventive method comprising the

Steps:

la production of a pre-composite 9 from a first thermoplastic composite film 3 and a barrier film 6

or

Ib Production of a pre-composite 9 from a second thermoplastic composite film 4 and a barrier film 6

II Creation of a cutout 7 in the barrier film 6 of the preliminary composite 9, the barrier film 6 being removed within the cutout 7 III Provision of a first pane 1

IVa placing the pre-composite 9 made of the first thermoplastic composite film 3 and the barrier film 6 on the first pane 1, the first thermoplastic composite film 3 being applied in the vicinity of the first pane 1

or

IVb placing a first thermoplastic composite film 3 on the first pane 1

Va inserting a functional element 5 in the cutout 7 of the barrier film 6, the

Barrier film 6 encloses the peripheral edge 8 of the functional element 5 or

Vb placing a functional element 5 on the first thermoplastic composite film 3

By placing a second thermoplastic composite film 4 on the barrier film 6 and the functional element 5

or

Vlb placing the pre-composite 9 from the second thermoplastic composite film 4 and the barrier film 6 on the functional element 5, the barrier film 6 being applied in the vicinity of the functional element and enclosing the peripheral edge 8 of the functional element 5

VII Place a second pane 2 on the second thermoplastic composite film 4

Autoclaving the layer stack into a composite disc 100

LIST OF REFERENCE NUMBERS

1 first slice

2 second disc

3 first thermoplastic composite film

4 second thermoplastic composite film

5 functional element with electrically controllable optical properties

6 barrier film

7 cutout (of the barrier film)

8 peripheral edge of the functional element 5

9 Pre-composite of first thermoplastic composite film 3 or second thermoplastic composite film 4 and barrier film 6

10 black printing

11 active layer of the functional element 5

12 first surface electrode of the functional element 5

13 second surface electrode of the functional element 5

14 first carrier film

15 second carrier film

16 isolation lines

17 cutting tool

18 cuts

19 further thermoplastic composite films

20 additional carrier foils

21 infrared reflective coating

22 inner edge of the barrier film 6

100 composite washer

AA, BB ', CC' cut lines

Z enlarged area

S field of view B

M motor edge

D roof edge

Claims

claims

1. composite disc (100) containing a functional element (5) with electrically controllable optical properties at least comprehensively in this order

- a first disc (1),

a first thermoplastic composite film (3) with at least one plasticizer,

- a functional element (5) with a peripheral edge (8),

a barrier film (6) with a cutout (7) into which the functional element (5) is inserted,

a second thermoplastic composite film (4) with at least one plasticizer,

- a second disc (2),

in which

- The barrier film (6) surrounds the functional element (5) in a frame shape and is in direct contact with the circumferential edge (8) of the functional element (5) and

- The barrier film (6) contains at most 0.5 wt .-% plasticizer and prevents the diffusion of plasticizer through the barrier film (6).

2. Composite pane (100) according to claim 1, wherein the functional element (5) is a polymer dispersed liquid crystal (PDLC) film.

3. composite disc (100) according to claim 1 or 2, wherein the thickness of the barrier film (6) and the thickness of the functional element (5) by at most 30%, preferably by at most 20%, particularly preferably by at most 15%, and in particular the The thickness of the barrier film (6) and the thickness of the functional element (5) are essentially the same.

4. Composite pane (100) according to one of claims 1 to 3, wherein the barrier film (6) has a thickness of 0.1 mm to 1.0 mm, preferably 0.3 mm to 0.5 mm, particularly preferably 0, Has 40 mm to 0.45 mm.

5. Composite pane (100) according to one of claims 1 to 4, wherein the first and / or the second thermoplastic composite film (3, 4) at least 3 wt .-%, preferably at least 5 wt .-%, particularly preferably at least 20 wt. %, more preferably at least 30% by weight and in particular at least 40% by weight of a plasticizer and the plasticizer preferably contains aliphatic diesters of tri or tetraethylene glycol, particularly preferably triethylene glycol bis (2-ethylhexanoate), or consists thereof.

6. Composite pane (100) according to one of claims 1 to 5, wherein the thermoplastic composite films (3, 4) at least 60% by weight, preferably at least 70% by weight, particularly preferably at least 90% by weight and in particular at least 97 Wt .-% polyvinyl butyral (PVB) contain.

7. Composite pane (100) according to one of claims 1 to 6, wherein the barrier film (6) contains or consists of polyethylene terephthalate (PET) or polyvinyl fluoride (PVF) and is preferably free of plasticizers.

8. Composite pane (100) according to one of claims 1 to 7, wherein the material composition of the barrier film (6) differs in terms of its main mass component from the main mass component of the thermoplastic composite films (3, 4).

9. The composite pane (100) according to claim 8, wherein the barrier film (6) contains polyethylene terephthalate (PET) as the main mass component and the thermoplastic composite films (3, 4) contain polyvinyl butyral (PVB) as the main mass component.

10. Composite pane (100) according to one of claims 1 to 9, wherein the barrier film (6) in the form of a pre-composite (9) made of barrier film (6) and first thermoplastic composite film (3) or in the form of a pre-composite (9) made of barrier film ( 6) and the second thermoplastic composite film (4) is placed in the layer stack of the composite pane (100) and the barrier film (6) is in direct contact with the thermoplastic composite film (3, 4) of the preliminary composite (9).

11. A method for producing a composite pane (100) with a functional element (5) according to one of claims 1 to 10, wherein at least

a first thermoplastic composite film (3) is arranged flat on a first pane (1), a functional element (5) and a barrier film (6) surrounding the peripheral edge (8) of the functional element (5) on the first thermoplastic composite film (3) are arranged, a second thermoplastic composite film (4) is arranged on the functional element (5) and the barrier film (6), a second pane (2) is placed on the second thermoplastic composite film (4) and the layer stack is connected to a composite disc (100) by autoclaving, wherein

the barrier film (6) contains at most 0.5% by weight of plasticizer and prevents the diffusion of plasticizer through the barrier film (6) and

the first thermoplastic composite film (3) and the second thermoplastic

Composite film (4) each contain at least one plasticizer.

12. The method of claim 1 1, wherein the barrier film (6) is inserted as a pre-composite (9) together with the first thermoplastic composite film (3) or the second thermoplastic composite film (4) in the layer stack.

13. The method according to claim 12, wherein the barrier film (6) is connected to the first thermoplastic composite film (3) or the second thermoplastic composite film (4) under the action of heat and pressure to form a pre-composite (9).

14. The method according to claim 12 or 13, wherein a pre-composite (9) from a substantially congruent thermoplastic composite film (3, 4) and a barrier film (6) is created, in at least one cutout (7) the barrier film (6) Preliminary composite (9) is removed and when the layer stack is folded, the functional element (5) is inserted into the cutout (7) of the barrier film (6).

15. Use of a composite pane (100) according to one of claims 1 to 10 as a windshield or roof pane of a vehicle, the electrically controllable functional element (5) serving as a sun visor or as a privacy screen.