EP3826836A1

EP3826836A1 - Method for producing a composite pane comprising a functional element having electrically controllable optical properties

Info

Publication number: EP3826836A1
Application number: EP19732041.9A
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: 2018-07-24
Filing date: 2019-06-24
Publication date: 2021-06-02
Also published as: CN110944837A; US20210008843A1; WO2020020549A1

Abstract

The invention relates to a method for producing a composite pane (100) comprising a functional element (5) having electrically controllable optical properties, wherein at least a) a first pre-composite (3) consisting of a first thermoplastic composite film (3a) and a first barrier film (3b) as well as a second pre-composite (4) consisting of a second thermoplastic composite film (4a) and a second barrier film (4b) are provided, and the pre-composites (3, 4) are cut substantially to the dimensions of the composite pane (100) to be produced, b) the barrier films (3b, 4b) are peripherally trimmed (7), c) a first pane (1), the first pre-composite (3), a functional element (5), the second pre-composite (4) and a second pane (2) are arranged one above the other in this order, wherein the barrier films (3b, 4b) are arranged in a planar manner directly adjacent to the functional element (5), enclose the peripheral edge (8) of the functional element (5), and at least sections of which touch one another in a planar manner in a projection u projecting beyond the functional element (5), d) the stack of layers consisting of, in this order, a first pane (1), a first thermoplastic composite film (3a), a first barrier film (3b), a functional element (5), a second barrier film (4b), a second thermoplastic composite film (4a), and a second pane (2) is joined by autoclaving to form a composite pane (100).

Description

Method for producing a composite pane with a functional element with electrically controllable optical properties

The invention relates to a method for producing a composite pane with a functional element with electrically controllable optical properties, 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.

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 strong scattering of 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.

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.

DE 20 2018 102 520 U1 describes a composite pane with a functional element with electrically controllable optical properties, which is contacted via strip-shaped busbars.

WO 2014/086555 discloses a composite pane comprising a functional element, a thermoplastic film comprising a luminescent material being introduced between the outer pane of the composite pane and the functional element.

WO 2017/157626 describes a windshield with a functional element as an electrically controllable sun visor, areas of the thermoplastic intermediate layer which connect the functional element to the outer pane being colored or tinted.

The problem of edge sealing of an SPD functional element in relation to the plasticizers diffusing in from the thermoplastic intermediate layer of the composite pane is described in WO 2010/032068. US 2005/0227061 A1 likewise describes the edge sealing of SPD functional elements in composite panes, strip-shaped PET films being attached to the edges of the functional element.

The present invention is therefore based on the object of developing an improved method for producing a composite pane, which provides a composite pane with a functional element with high aging resistance and enables simplified handling and a high degree of automation. In addition, a composite pane with a functional element with improved aging resistance and its use are to be provided.

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

The invention relates to a method for producing a composite pane with a functional element with electrically controllable optical properties. Barrier films are used in the vicinity of the functional element, which seal the open edge of the functional element and thus prevent aging. According to the invention, these barrier films are used in the form of a pre-composite of the barrier film and a thermoplastic film. In a first step of the method (step a), a first pre-composite of a first thermoplastic composite film and a first barrier film and a second pre-composite of a second thermoplastic composite film and a second barrier film are provided. The term bilayer is also familiar for such a flat film pre-composite consisting of thermoplastic composite film and barrier film. The pre-composites are essentially cut to the dimensions of the composite pane to be manufactured. Then or at the same time, the barrier foils are cut all the way round (step b). The barrier film is selectively removed in the edge area of the pre-composites. The circumferential edge of a barrier film is accordingly set back in the direction of the center of the surface of the precomposite with respect to the circumferential edge of the thermoplastic composite film of the same pre-composite. Accordingly, only the first thermoplastic composite film or the second thermoplastic composite film remains in the edge region of the first or second pre-composite. The correspondingly prepared preliminary composites are then combined with at least one functional element and at least two panes in a layer stack (step c) and laminated over a large area (step d). Additional elements, such as further film components, can also be used. to Lamination of the arrangement is first of all a layer stack formed from at least a first pane, the first preliminary bond, a functional element, the second preliminary bond and a second pane, which are arranged one above the other in this order (step c). It should be noted that the barrier foils are arranged immediately adjacent to the functional element and enclose the peripheral edge of the functional element. The barrier foils are cut in step b so that there is a protrusion beyond the circumferential edge of the functional element. This is an at least sectionally common projection of the barrier films, in which the first and second barrier films touch one another. As a result, the edge of the functional element is closed by means of the barrier films, so that no plasticizers from the thermoplastic composite films can get into the active layer of the functional element. The protrusion of the first and second barrier films over the edge of the functional element can be identical to one another or differ. A slight misalignment of the two overhangs can also be caused by the bilayer not being completely congruent. Even in such a case, however, there is a section-wise common overhang that ensures secure sealing. Finally, the layer stack consisting of the first pane, first thermoplastic composite film, first barrier film, functional element, second barrier film, second thermoplastic compound film and second pane arranged in at least this order is connected to form a compound pane in the autoclave process (step d).

The method according to the invention provides a composite pane with a functional element with high resistance to aging, while at the same time simple handling is ensured by the use of pre-bonds (bilayers) made of thermoplastic composite film and barrier film. Because these foils are used as bilayers, the barrier foil retains its inherent stability even after the barrier foil has been cut back in the edge region of the bilayer. Particularly in the case of small-area functional elements, the exact positioning of a barrier film which is adapted to the functional element in size is difficult, since this must be applied with a precise fit and it must be prevented from slipping in the layer stack. This is only possible to a limited extent with the methods known from the prior art. In addition, electrostatic effects occur when using a single barrier film, which further complicate handling. By using bilayers according to the invention, the barrier films can be brought into any shape. This also enables a rounded or round edge design of the functional element. Masking the open edge of the In contrast, functional elements, as known from the prior art, are not possible with round geometries, since the adhesive tape is wrinkled. Inclusions of air bubbles and the resulting optical disturbances or impairments are avoided by means of the method according to the invention, since the barrier films lie evenly and wrinkle-free on the functional element.

The preliminary composites according to the invention have no adhesion promoters, adhesion-improving coatings and / or adhesives. This applies to all of the film surfaces of the preliminary composites. There is no adhesion promoter between the barrier films and the associated thermoplastic composite film, nor between the sections of the barrier films touching one another, or 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 clouding of the edge region of the functional element can be prevented. The use of bilayers according to 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 a composite pane with a functional element which is improved in its aging resistance accessible with a significantly reduced production outlay.

In an advantageous embodiment of the method according to the invention, the barrier films are cut back in step b such that the common projection u exists on all sides, that is to say on all of the four or more side edges of the functional element. The first barrier film is arranged in the form of the first pre-composite on the underside of the functional element and the second barrier film is arranged in the form of the second pre-composite on the top of the functional element. In the area of the protrusion, a protruding area of the first barrier film immediately touches a protruding one Area of the second barrier film. The bottom and top of a film-like functional element mean the two large surfaces which are arranged parallel to the outer pane and inner pane, in other words the outer surfaces and the inner surfaces of the functional element. Side edges describe the surfaces of the functional element which run orthogonally to them and which are very thin in the case of film-like functional elements. The barrier films can cover the top and / or the bottom of the functional element only in sections or completely.

The first and the second preliminary composite are generated before method step a). The first barrier film is preferably connected to the first thermoplastic composite film by heating to form a first pre-composite, and the second barrier film is connected to the second thermoplastic composite film by heating to form a second pre-composite. 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, which is made up of a barrier film and a thermoplastic composite film, can be wound up on a roll and can be produced and stored in advance as required.

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 by Pair of rollers with a temperature of 45 ° C and thereby pressed together flat and rolled up as a pre-composite on a roller. The statements relating generally to a preliminary network apply to the first and second preliminary networks.

In a preferred embodiment, cutouts are made in the barrier films of the preliminary composites. The cutouts are placed so that the barrier films cover the edges of the functional element and have an overlap with the functional element. Accordingly, the barrier films in the area of the functional element itself, outside the edge area of the functional element, are removed. The barrier films are not required in these areas. The barrier films are therefore preferably only present in the edge region of the functional element, where sealing of the open edges of the functional element is necessary. This is advantageous because there is improved adhesion in the cutout areas of the barrier films. The barrier film and the adjacent carrier film of the functional element can be made of PET, for example. However, two PET films show no adhesion to one another even after the pane has been connected in an autoclave process. This leads to a deterioration in the optical quality in this area. Since commercially available PET films generally have a smooth, unstructured surface, air inclusions are also favored between two such films, which also have negative effects on the optical quality of the composite pane. A cutout in one or both barrier films accordingly leads to an improved optical quality. Furthermore, the thickness of the layer structure is reduced by removing the barrier film in the area of the cutout. The cutouts are preferably set back from the edge of the functional element by at least 2 mm, particularly preferably by at least 5 mm, in the direction of the surface center of the functional element. The functional element and the barrier films thus overlap by at least this amount. This is advantageous for reliable sealing. The area of overlap between the barrier films and the functional element extends all the way along the edges of the functional element. The width of the overlap area is preferably a maximum of 20 mm. For example, the overlap area can have a width of 10 mm.

According to the invention, the first and second barrier films of the pre-composites are cut so that each barrier film has a protrusion u over the functional element and projecting sections of the barrier film are arranged immediately adjacent and at least in sections touch. The terms “protrusion” or “protrude” mean, as is generally used: protrude beyond something in the lateral (horizontal) direction. In this case, the barrier film protrudes beyond the functional element in the plane of the functional element. Lateral means here, as is commonly used: sideways or sideways.

The projection u according to the invention therefore differs from the overlap area already described, in which the barrier film is arranged directly on a section of the top or bottom of the functional element and overlaps with it.

The cutouts and the cut back of the barrier films are preferably carried out in such a way that the first barrier film and / or the second barrier film each form the shape of a continuous peripheral frame. This is advantageous with regard to the dimensional stability of the barrier films in the pre-composite.

In one possible embodiment of the invention, in process step c) a thermoplastic frame film is arranged between the first pane and the first thermoplastic composite film and / or between the second pane and the second thermoplastic composite film, which covers the area of the intermediate layer in which the functional element is introduced, border. In the pane area beyond the side edges of the functional element, the thermoplastic frame film is therefore inserted all around in the layer stack. The frame film is designed like a frame with a recess into which the functional element surrounded by the pre-connections is inserted. The structure and material composition of the frame film can correspond to that of the first and / or second thermoplastic composite film, the cutout having been made by cutting out. Alternatively, the thermoplastic frame film can also be composed of several film sections around the functional element. The outer side edges of the thermoplastic frame film are preferably arranged congruently with the side edges of the first and the second thermoplastic composite film. The thickness of the thermoplastic frame film can differ from the thickness of the first and / or second composite film. The thickness of the thermoplastic frame film is preferably selected such that it has approximately the same thickness as the functional element. This compensates for the local difference in thickness of the windshield, which is introduced by the localized functional element, so that glass breakage during lamination can be avoided. According to the invention, since the frame film is inserted between the first thermoplastic composite film and the first pane and / or between the second thermoplastic composite film and the second pane, the frame film has no direct contact with the functional element. The functional element is sealed by placing bilayers on both sides through the first and second barrier films. The frame film is only in contact with the adjacent pane and the thermoplastic composite film of the adjacent bilayer and fuses with the thermoplastic composite film during the lamination process. The individual film components are still preserved to the extent that they can also be detected in the laminated composite pane.

In a further preferred embodiment of the method according to the invention, no thermoplastic frame film is inserted into the layer stack. This is possible, for example, if the functional element has a comparatively small thickness and the local difference in thickness is therefore small. However, whether a frame film can be dispensed with also depends on the geometry of the composite pane to be produced. Especially with complex geometries or strong bends in the edge area, even a small local difference in thickness can promote glass breakage. It is therefore not possible to make a blanket forecast above which difference in thickness a thermoplastic frame film should be used. Experience has shown, however, that with a local thickness difference of less than or equal to 150 pm, preferably less than or equal to 120 pm, a thermoplastic frame film can generally be dispensed with.

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 the number of ethylene glycol units and the last digit the number of carbon atoms in the carboxylic acid part of the compound designated. For example, 3G8 stands for triethylene glycol bis (2-ethylhexanoate), ie for a compound of the formula C4H9CH (CH2CH3) CO (0CH ₂ CH ₂ ) 30 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).

The first thermoplastic composite film, the second thermoplastic composite film and / or the thermoplastic frame film further preferably 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 ,

In an advantageous embodiment of the method according to the invention, the first and the second barrier film are selected such that they prevent the diffusion of plasticizers from the intermediate layer through the barrier film.

In an advantageous embodiment of the method according to the invention, low-plasticizer barrier films are selected, preferably with a plasticizer content of less than 3% by weight, particularly preferably less than 1% by weight and in particular 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 preferably used in the process according to the invention. The barrier films contain or consist of polyethylene terephthalate (PET) or polyvinyl fluoride (PVF) in particular. These materials are free of plasticizers, which further improves the aging resistance of the functional element compared to the use of low-plastic barrier films.

The barrier film can alternatively also contain low-plasticizer polyvinyl butyral (PVB) with a plasticizer content of less than 3% by weight.

In a particularly preferred embodiment of the method according to the invention, the material composition of the barrier film differs within the preliminary composites and the thermoplastic composite film according to its main mass components. 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 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 invention further comprises a composite pane containing a functional element with electrically controllable optical properties produced in the method according to the invention. In this sequence, the composite pane laminated as a layer stack comprises a first pane, a first pre-composite of a first thermoplastic composite film with at least one plasticizer and a first barrier film, a functional element, a second pre-composite of a second thermoplastic composite film with at least one plasticizer and a second barrier film and a second disc. The first barrier film is in direct contact with the peripheral edge of the functional element. The first For this purpose, barrier film is placed in the layer stack in such a way that it covers at least the partial area of the functional element in which its peripheral edge lies on a surface of the functional element. The second barrier film is also in direct contact with the peripheral edge of the functional element. The second barrier film is attached to the opposite surface of the functional element compared to the first barrier film and covers at least the portion of the functional element in which it has a peripheral edge. Since the barrier films are arranged directly adjacent to the functional element in the area of the circumferential edge, they enclose the circumferential open edge of the functional element after lamination of the composite pane. In the area adjacent to the open edge of the functional element, the first and the second barrier film touch at least in sections directly over the surface. The circumferential area along the edge of the functional element, in which the first and second barrier films touch, has a protrusion u projecting beyond the functional element. This is the term for the common overlap of the barrier films. Irrespective of this, a single one of the barrier films can also protrude further beyond the functional element.

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 first barrier film and the second barrier film are preferably each in the form of a continuous 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 circumferential cut back of the barrier films and the cutout in the area of the functional element. The frame-like shape is advantageous with regard to the dimensional stability of the barrier films in the pre-composite. In addition, an improved seal can be achieved by means of a continuous, continuous shape. 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 films along the edges of the functional element is thus advantageous both in terms of simplified production and in terms of product quality.

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.

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 outer pane and inner pane arbitrarily describe two different panes. In particular, the outer pane can be referred to as a first pane and the inner pane as a second 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. In an advantageous embodiment of a composite pane according to the invention, the projection u of the barrier film over the functional element is at least 1 mm, preferably at least 2 mm, particularly preferably at least 5 mm and in particular at least 8 mm, for example 10 mm. The projection u is thus determined in the lateral dimension parallel to the two largest dimensions of the functional element or the composite pane.

In an advantageous embodiment of a composite pane according to the invention, the projection u of the barrier film over the functional element is less than 50 mm, preferably less than 30 mm and particularly preferably less than 20 mm.

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 thickness of the barrier films is in each case 10 pm to 150 pm, preferably 15 pm to 100 pm, particularly preferably 20 pm to 70 pm, for example 25 pm or 50 pm. Such thin film thicknesses are advantageous in order to increase the local difference in thickness between the intermediate layer with a functional element and the intermediate layer without a functional element as little as possible. This has a positive effect with regard to limiting the stresses resulting from the difference in thickness.

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 are optionally connected to the surface electrodes via so-called bus bars, for example strips of an electrically conductive material or electrically conductive imprints.

The surface electrodes are preferably designed as transparent, electrically conductive layers. The surface electrodes preferably contain at least one metal, one 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 thickness of 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 in this case is more stable than with mechanical cutting with mechanically cut side edges, there may be a risk that the material retracts, 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 inner 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 and laminated to one another, the functional element being inserted between the two layers. The regions of the thermoplastic composite films overlapping with the functional element then form the regions which connect the functional element to the panes. In other areas of Discs where the thermoplastic composite films are in direct contact with one another can fuse during lamination.

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 via which the functional element is connected to the first and / or second pane is 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 are used according to the invention in the form of a bilayer with a barrier film, can be tinted or colored. This can also apply to the thermoplastic frame film. 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 first pane corresponds to the outer pane and the area of the first 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 second thermoplastic composite film between the functional element and the inner pane (second pane) can optionally also be colored or tinted.

In a preferred embodiment of the composite pane according to the invention, the first and second thermoplastic composite films are tinted and are used according to the invention as bilayers, each with a barrier film. Between the first pane (here: outer pane) and the first 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 first thermoplastic composite film, while the connection to the first pane takes place via the further thermoplastic composite film. The second thermoplastic composite film ensures a connection to the second pane either directly or with the interposition of a thermoplastic frame film. Such a structure is advantageous, for example, as a roof window of a motor vehicle, since the infrared-reflecting coating causes the undesired heating of the vehicle interior Reduced 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. However, a button for regulating the sun visor can also 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 is arranged in the area between the central field of vision and the upper edge of the windshield. 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 essentially parallel to the upper edge of the Windshield trained. 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, preferably adapted to a possible bending of the upper edge of the windshield, in particular essentially parallel to the upper 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 viewed through the composite pane by an opaque cover print or covered by an outer frame. 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 implement the sun visor with at least two 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 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,

1 c shows a layer stack of a further embodiment of the invention

Composite pane with thermoplastic frame film before lamination of the pane, FIG. 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 3 shows a cross section through an embodiment of the invention

Composite pane with thermoplastic frame film,

Figure 4 shows a cross section through a further embodiment of the invention

Composite pane with thermoplastic frame film,

Figure 5a is a plan view of a further embodiment of an inventive

Composite pane as roof pane with functional element,

FIG. 5b shows a cross section through the composite pane from FIG. 5a along the section line BB,

Figure 6 is a plan view of a further embodiment of an inventive

Composite windshield with sun visor.

Figure 1 a shows a pre-composite 3 or 4 according to the invention made of a thermoplastic composite film 3a or 4a and a barrier film 3b or 4b and the processing steps for cutting the barrier film, shown as states A to C. This can be a composite analogously to one another 3 of the first thermoplastic composite film 3a act with the first barrier film 3b, or a composite 4 of the second thermoplastic composite film 4a with the second barrier film 4b. The preliminary composites 3 and 4 according to state A) in FIG. 1 a were produced by a thermoplastic composite film 3a or 4a together with a barrier film 3b or 4b through a heated pair of rollers at a temperature of 45 ° C. and a speed of 4 m / min is performed. The rollers press the foils together under heating, which combine to form a pre-bond. The thermoplastic composite films 3a and 4a consist of 78% by weight of polyvinyl butyral (PVB) and 20% by weight of triethylene glycol bis (2-ethylhexanoate) as plasticizers and each have a thickness of 0.38 mm, while the barrier films 3b and 4b essentially consist of polyethylene terephthalate (PET) and are each 50 pm thick. The barrier film 3b and 4b consist here, for example, essentially of PET, that is to say at least 97% by weight. The barrier films 3b and 4b contain less than 0.5% by weight of plasticizer and are preferably free of plasticizer. The barrier films 3b, 4b are suitable for decisively reducing or preventing the diffusion of plasticizer from the thermoplastic composite films 3a, 4a. Preliminary composites 3 and 4 can be constructed with the same or different materials and film thicknesses. In such a pre-assembly 3 or 4, cuts 18 are made into the barrier film 3b or 4b of the pre-assemblies by means of a cutting tool 17 3, 4 introduced. The depth of cut is chosen so that the thermoplastic composite film remains essentially undamaged. The cuts 18 made in the barrier film 3b, 4b produce a cutback 7 in the edge region of the barrier films 3b, 4b, as a result of which the barrier films 3b, 4b are set back with respect to the peripheral edge of the later composite pane. A cutout 6 is also produced within the surface of the barrier films 3b, 4b. The cuts 18 required for the cut back 7 in the edge region and the cutout 6 within the surface of the barrier films 3b, 4b are shown in state B) of FIG. 1a and run all the way round. 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 films 3b, 4b are removed in the area of the cut back 7 and the cutout 6. This is possible by lifting the barrier film 3b, 4b to be detached at the edge of a cut 18. Starting from such a raised corner, the regions of the barrier film 3b, 4b to be removed are pulled off. This can be done with moderate effort and without damaging the foils. A pre-composite 3, 4 thus results from a continuous thermoplastic composite film 3a, 4a and a frame-shaped barrier film 3b, 4b, which is only present at the locations of the pre-bundle where it is required to seal the functional element (see C) in FIG. 1a ). A single barrier film 3b, 4b frame-shaped blank has no dimensional stability, so that it cannot be handled mechanically and hardly by hand. Due to the use of a bilayer (pre-assemblies 3, 4) according to the invention, the barrier films 3b, 4b can be cut in any geometries without any restrictions. The stability and manageability of the arrangement is always ensured by the thermoplastic composite film 3a, 4a. 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. On a first pane 1 made of clear soda-lime glass with a thickness of 2.1 mm, a bilayer (pre-composite 3 according to FIG. 1 a) made of a first thermoplastic composite film 3a and a first barrier film 3b present on partial areas of the composite film 3a is placed , The thermoplastic composite film 3a is placed adjacent to the first pane 1. The first disc 1 1b has a thickness of 2.1 mm and represents the outer pane of the windshield of a motor vehicle. A functional element 5 is placed on the first barrier film 3a, the dimensions of the barrier film 3a and the functional element 5 being so matched to one another that that the peripheral edge of the functional element 5 rests on the surface of the barrier film 3a. The functional element is designed as a PDLC element with a thickness of 100 pm. A further bilayer (pre-composite 4 according to FIG. 1 a) is applied to the functional element 5 and points with a second barrier film 4 b in the direction of the functional element 5. A second pane 2, which closes the layer stack, is placed over the second thermoplastic composite film 4a. The second pane 2 has a thickness of 1.6 mm and also consists, for example, of a clear soda-lime glass. In this case, the second pane 2 represents the inner pane of a windshield and is bent congruently with the first pane. The barrier foils 3b, 4b are cut according to FIG. 1a so that they are substantially congruent with one another according to FIG. 1b and together cover the peripheral edge of the functional element 5. Any other films, for example functional films or colored films, can be arranged between the first thermoplastic composite film 3a and the first pane 1 or between the second thermoplastic composite film 4a and the second pane 2. The preliminary composites 3, 4 also remain in the vicinity of the functional element 5 with an expansion of the layer stack with direct contact between the functional element 5 and barrier films 3b, 4b. Such a layer stack can be collapsed by machine. The use of pre-composites therefore represents a significant simplification with regard to the manufacturing process of the composite pane.

1 c shows a layer stack for producing the composite pane according to the invention using the pre-composite according to FIG. 1 a. The structure of the layer stack essentially corresponds to that described in FIG. 1b. In contrast to this, the functional element 5 has a thickness of 400 μm. In order to compensate for the difference in thickness between the area of the composite pane with functional element 5 and the area of the composite pane without functional element 5, a frame-shaped thermoplastic composite film 9 with a thickness of 0.38 mm is inserted into the layer stack. This can be arranged, for example, adjacent to the first disk 1 or adjacent to the second disk 2. The composition of the composite film 9 corresponds to the composition of the thermoplastic composite films 3a and 4a already described (FIG. 1 a). 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 3a, a second thermoplastic composite film 4a, a first barrier layer 3b, a second barrier layer 4b and a functional element 5. FIG. 2b shows a cross section of the composite disc according to Figure 2a along the section line AA shown. 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 3a and the second thermoplastic composite film 4a. A functional element 5 is inserted between the first thermoplastic composite film 3a and the second thermoplastic composite film 4a, which is also connected to the panes 1, 2 via the thermoplastic composite films 3a, 4a. A first barrier film 3b and a second barrier film 4b, which enclose the circumferential edge 8, are arranged along the circumferential edge 8 of the functional element. For this purpose, the first barrier film 3b and the second barrier film 4b lie directly on the opposite surfaces of the functional element 5. The barrier films 3b, 4b are positioned essentially congruently with one another and have an overlap x (see FIGS. 2a, 2b) of 10 mm with the functional element. Furthermore, the barrier films 3b, 4b have a projection u (see FIGS. 2a, 2b) of 10 mm beyond the circumferential edge 8 of the functional element 5. The barrier films 3b, 4b here have, for example, an overhang u on all sides and an overlap x on all sides over the functional element 5. Here, on all sides means that the projection u and the overlap x are present on each side edge of the peripheral edge 8. In the area of the projection u, the surfaces of the first barrier film 3b and the second barrier film 4b touch directly. As a result, the peripheral edge 8 of the functional element 5 is completely surrounded by the barrier films 3b, 4b. The barrier films 3b, 4b are shaped as continuous, continuous frame-shaped films. Due to the use of the barrier foils 3b, 4b as pre-composites 3, 4 with the thermoplastic composite foils 3a, 4a, such complex geometries of the barrier foils are possible and easy to handle. The protrusion u and the overlap x further improve the sealing of the peripheral edge 8, so that 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, diffusion of the Plasticizer from the thermoplastic composite films 3a, 4a in the functional element 5 and an accompanying degradation of the functional element 5 avoided.

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, 50 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 3a, 4a 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 films 3b, 4b here essentially consist of PET, for example, at least 97% by weight. The barrier films 3b, 4b contain less than 0.5% by weight of plasticizer and are suitable for preventing the diffusion of plasticizer from the thermoplastic composite layers 3a, 4a via the peripheral edge 8 into the functional layer 5.

The barrier films 3b, 4b are 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 additionally in direct contact with the open cross section of the functional element 5 along the circumferential edge 8. In the region of the protrusion x the barrier films 3b, 4b are in direct planar contact with one another. In direct contact means that no other components or chemical compounds, such as Adhesives are arranged between the barrier films 3b, 4b and between the barrier films and the functional element 5. According to the prior art, the blocking films are prevented from slipping during assembly by means of adhesive connections. According to the invention, an adhesive connection is not necessary and is not desired. Slipping of the adhesive films is achieved by using pre-bonds 3, 4, each of which comprises a barrier film 3b, 4b and a thermoplastic composite film 3a, 4a. The embodiment of the invention described in FIGS. 2a, 2b and 2c contains pre-composites 3, 4 produced according to FIG. 1a. 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 films 3b, 4b lie evenly on the functional element 5. The barrier foils 3b, 4b according to the invention in the region of the peripheral edge of the functional element 5 are firmly pressed and fixed there by the internal pressure in the laminated composite pane 100, 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. 3 shows a further development of the composite pane 100 according to the invention from FIGS. 2a, 2b and 2c. The composite pane 100 from FIG. 3 essentially corresponds to the composite pane 100 from FIGS. 2a, 2b and 2c, so that only the differences are dealt with below.

In this embodiment, a thermoplastic frame film 9 is arranged in sections between the second thermoplastic composite film 4a and the second pane 2. The thermoplastic frame film 9 consists for example of the same material as the thermoplastic composite films 3a, 4a. The thermoplastic frame film 9 has a cutout in which the functional element 5 with the barrier films 3b, 4b and the thermoplastic composite films 3a, 4a is inserted in a precisely fitting manner, that is to say flush on all sides. The thermoplastic frame film 9 thus forms a kind of passe-partout for the functional element 5 and the film sections of the composite film and barrier films surrounding it. The thermoplastic frame film 9 can compensate for the differences in thickness that are caused by the material thickness of the functional element 5. The thicknesses of the functional element 5 and the thermoplastic frame film correspond to the values described in FIG. 1 c. FIG. 4 shows a further embodiment of the composite pane 100 according to FIG. 3 according to the invention. The composite pane 100 from FIG. 4 essentially corresponds to the composite pane 100 from FIG. 3, the barrier films 3b, 4b having no cutouts 6. As a result, the entire functional elements 5 are enclosed by the barrier films 3b, 4b.

FIG. 5a 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. 5b shows a cross section of the roof pane according to FIG. 5a along the section line BB '. The roof pane comprises a first pane 1, a second pane 2, a first thermoplastic composite film 3a, a second thermoplastic composite film 4a, a first barrier layer 3b, a second barrier layer 4b and a functional element 5. The first and the second pane 1, 2 are congruent bent towards each other. The first pane 1 represents the outer pane of the glazing, that is to say it is oriented towards the vehicle surroundings, while the second pane 2 is the inner pane of the composite pane and faces the vehicle interior. The first pane 1 consists of clear soda-lime glass with a thickness of 2.1 mm. The second pane 2 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 composite film 3a, the second thermoplastic composite film 4a and a further thermoplastic composite film 19. A functional element 5 is inserted between the first thermoplastic composite film 3a and the second thermoplastic composite film 4a, which is also connected to the panes 1, 2 via the thermoplastic composite films 3a, 4a. A first barrier film 3b and a second barrier film 4b, which enclose the circumferential edge 8, are arranged along the circumferential edge 8 of the functional element. For this purpose, the first barrier film 3b and the second barrier film 4b lie directly on the opposite surfaces of the functional element 5. The barrier films 3b, 4b are positioned essentially congruently with one another. The functional element 5 and the barrier films 3b, 4b overlap by x = 15 mm in order to achieve a good seal of the edge 8. The protrusion u of the barrier films 3b, 4b over the circumferential edge 8 of the functional element 5 is 10 mm. The barrier films 3b, 4b here have an all-round projection u and an all-round overlap x over the functional element 5. Here, on all sides means that the projection u and the overlap x are present on each side edge of the peripheral edge 8. In the area of the projection u, the surfaces of the first barrier film 3b and the second barrier film 4b touch directly. As a result, the peripheral edge 8 of the functional element 5 is completely covered by the barrier films 3b, 4b enclosed. The protrusion u and the overlap x further improve the sealing of the peripheral edge 8, so that 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 3a, 4a into the functional element 5 and a related degradation of the functional element 5 are avoided. The first thermoplastic composite film 3a and the second thermoplastic composite film 4a 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 (first pane 1). The further thermoplastic composite film 19 is used 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 first thermoplastic composite film 3a. The infrared-reflecting coating 21 is oriented in the direction of the first pane 1 (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 3a, 4a and the barrier films 3b, 4b correspond to the dimensions described in FIGS. 2a-2c.

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 pane 1. A black print 10 can optionally also be applied to the inside of the second pane. The circumferential edge 8 of the functional element 5 lies in the area of the black print 10, so that it is included Viewing the roof window from the outside is not recognizable. 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 films 3b, 4b are 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 additionally in direct contact with the open cross section of the functional element 5 along the circumferential edge 8. In the region of the protrusion x the barrier films 3b, 4b are in direct planar contact with one another. Also according to the exemplary embodiment in FIGS. 5a and 5b, no adhesive or other adhesion-promoting substances are used, but the barrier films 3b, 4b are used as pre-composites 3, 4 according to FIGS. 1a and 1b with the thermoplastic composite films 3a, 4a. The barrier foils 3b, 4b according to the invention in the region of the peripheral edge of the functional element 5 are firmly pressed and fixed there by the internal pressure in the laminated composite pane 100, 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. 6 shows a plan 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 120 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 FIG. 6 comprises a trapezoidal composite pane 100 with a first pane 1 as the outer pane and a second pane 2 as the inner pane, which are connected to one another via two thermoplastic composite films 3a, 4a. The first pane 1 has a thickness of 2.1 mm and consists of a green colored soda-lime glass. The second pane 2 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 not shown in detail here, since it essentially corresponds to the structure according to FIG. 3. Outside the area in which the functional element 5 is inserted into the composite pane 100, one or more thermoplastic composite films can optionally be inserted.

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 3a is connected to the first pane 1, the second thermoplastic composite film 4a is connected to the second pane 2. A thermoplastic frame film 9 located between the first thermoplastic composite film 3a and the first pane 1 has a cutout in which the cut PDLC multilayer film is inserted with an exact fit, that is to say flush on all sides. The thermoplastic frame film 9 thus forms a kind of passe-partout for the functional element 5, which is thus encapsulated all around in thermoplastic material and thus protected. In the area of the peripheral edge 8 of the functional element 5, a first barrier film 3b and a second barrier film 4b are inserted into the layer stack, which enclose the edge 8 and seal the functional element 5. The first barrier film 3b is used as a pre-composite 3 with the first thermoplastic composite film 3a, while the second barrier film 4b is used as a pre-composite 4 with the second thermoplastic composite film 4a.

The first thermoplastic composite film 3a has a tinted area which is arranged between the functional element 5 and the first pane 1 (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 diffusive state. This makes the aesthetics of the windshield much more appealing. The first thermoplastic composite film 3a 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 and with the barrier films 3b, 4b located on this edge. However, this is not necessarily the case. It is also possible for the tinted area to protrude beyond the functional element 5 or, conversely, for the functional element 5 to protrude beyond the tinted area. In the latter case, the entire functional element 5 would not be connected to the first pane 1 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 3a, 4a, 9 according to FIGS. 1 to 6, a so-called “high flow PVB” can preferably be used, which has a greater flow behavior than standard PVB films. The layers flow more strongly around the barrier films 3b, 4b and the functional element 5, which creates a more homogeneous visual impression and the transition from the functional element 5 to the composite films less stands out strongly. The “High Flow PVB” can be used for all or only for one or more of the thermoplastic composite films 3a, 4a, 9.

LIST OF REFERENCE NUMBERS

1 first slice

2 second disc

3 pre-composite of first thermoplastic composite film 3a and first barrier film 3b

3a first thermoplastic composite film

3b first barrier film

4 pre-composite of second thermoplastic composite film 4a and second barrier film 4b

4a second thermoplastic composite film

4b second barrier film

5 functional element with electrically controllable optical properties

6 cutout (of the barrier films)

7 cut back (in the edge area of the barrier films)

8 peripheral edge of the functional element 5

9 thermoplastic frame film

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

100 composite washer u overhang

x overlap

AA, BB 'cut lines

Z enlarged area

C field of view

M motor edge D roof edge

Claims

claims

1. A method for producing a composite pane (100) with a functional element (5) with electrically controllable optical properties, at least

a) a first pre-composite (3) from a first thermoplastic composite film (3a) and a first barrier film (3b) and a second pre-composite (4) from a second thermoplastic composite film (4a) and a second barrier film (4b) are provided and the pre-composites (3, 4) are essentially cut to the dimensions of the composite pane (100) to be produced,

b) a circumferential cut (7) of the barrier films (3b, 4b) is carried out,

c) a first pane (1), the first preliminary assembly (3), a functional element (5), the second preliminary assembly (4) and a second pane (2) are arranged one above the other in this order, the barrier films (3b, 4b) flatly adjacent to the functional element (5) with an at least sectionally common projection u over the circumferential edge (8) of the functional element and enclose the circumferential edge (8) of the functional element (5) and

d) the layer stack of the first pane (1), first thermoplastic composite film (3a), first barrier film (3b), functional element (5), second barrier film (4b), second thermoplastic compound film (4a) and second pane (2) is connected to a composite disc (100) by autoclaving.

2. The method according to claim 1, wherein before the method step a) the first barrier film (3b) with the first thermoplastic composite film (3a) is connected by heating to a first pre-composite (3) and / or the second barrier film (4b) with the second thermoplastic composite film (4a) is connected by heating to form a second pre-composite (4).

3. The method according to claim 1 or 2, wherein in step b) cutouts (6) in the barrier films (3b, 4b) of the preliminary composites (3, 4) are introduced.

4. The method according to any one of claims 1 to 3, wherein in process step c) between the first disc (1) and the first thermoplastic composite film (3a) and / or between the second disc (2) and the second thermoplastic composite film (4a) thermoplastic frame film (9) is arranged covering the area of the first framed thermoplastic composite film (3a) and / or the second thermoplastic composite film (4a) into which the functional element (5) is introduced.

5. The method according to any one of claims 1 to 4, wherein the first thermoplastic composite film (3a) and / or the second thermoplastic composite film (4a) each contain at least one plasticizer.

6. The method according to claim 5, wherein the first and the second thermoplastic composite film (3a, 4a) at least 3 wt .-%, preferably at least 5 wt .-%, particularly preferably at least 20 wt .-%, even more preferably at least 30 wt .-% and in particular contain at least 40 wt .-% of a plasticizer and the plasticizer preferably contains or consists of aliphatic diesters of tri- or tetraethylene glycol, particularly preferably triethylene glycol bis (2-ethylhexanoate).

7. The method according to any one of claims 1 to 6, wherein the thermoplastic composite films (3a, 4a) at least 60 wt .-%, preferably at least 70 wt .-%, particularly preferably at least 90 wt .-% and in particular at least 97 wt .-% % Polyvinyl butyral (PVB) included.

8. The method according to any one of claims 1 to 7, wherein the first and the second barrier film (3b, 4b) are designed such that they prevent the diffusion of plasticizer through the barrier film (3b, 4b).

9. The method according to claim 8, wherein the first and the second barrier film (3b, 4b) are free of plasticizers and preferably contain or consist of polyethylene terephthalate (PET) or polyvinyl fluoride (PVF).

10. The method according to any one of claims 1 to 9, wherein the material composition of the barrier films (3b, 4b) differs in terms of their main mass component from the main mass component of the thermoplastic composite films (3a, 4a).

11. The method according to claim 10, wherein the barrier films (3b, 4b) contain polyethylene terephthalate (PET) as the main mass component and the thermoplastic composite films (3a, 4a) contain polyvinyl butyral (PVB) as the main mass component.

12. Composite pane (100) containing a functional element (5) with electrically controllable optical properties produced in a method according to one of claims 1 to 11, at least comprehensively in this order

- a first disc (1),

a first pre-composite (3) made from a first thermoplastic composite film (3a) with at least one plasticizer and a first barrier film (3b), the first barrier film (3b) being in direct contact with the peripheral edge (8) of the functional element (5),

- a functional element (5),

a second pre-composite (4) made of a second thermoplastic composite film (4a) with at least one plasticizer and a second barrier film (4b), the second barrier film (4b) being in direct contact with the peripheral edge (8) of the functional element (5),

- a second disc (2),

in which

- The barrier foils (3b, 4b) are arranged flatly immediately adjacent to the functional element (5), enclose the peripheral edge (8) of the functional element (5) and touch each other flatly at least in sections in a protrusion protruding beyond the functional element (5).

13. The composite pane (100) according to claim 12, wherein the projection u of the barrier film (3a, 3b) over the functional element (5) is at least 1 mm, preferably at least 2 mm, particularly preferably at least 5 mm and in particular at least 8 mm, and the projection u of the barrier film (3a, 3b) over the functional element (5) is at most 50 mm, preferably at most 30 mm and particularly preferably at most 20 mm.

14. Composite pane (100) according to claim 12 or 13, wherein the functional element (5) is a polymer dispersed liquid crystal (PDLC) film.

15. Composite pane according to one of claims 12 to 14, wherein in the area of the functional element (5) cutouts (6) in the barrier films (3b, 4b) of the pre-composites (3, 4) are introduced and the first barrier film (3b) and / or the second barrier film (3c) are each designed in the form of a continuous peripheral frame.