WO2025219172A1 - Method for producing a composite pane with a functional insert part - Google Patents

Abstract

The invention relates to a method for producing a composite pane (100) with a functional insert part (6), having the following steps: a) producing a layer stack (15) containing - a first pane (1) with a first surface (I) and a second surface (II) and a second pane (3) with a third surface (III) and a fourth surface (IV), said second surface (II) and third surface (III) facing one another, - at least one first connecting film (2), at least one second connecting film (4), and at least one frame film (5) which are provided between the first pane (1) and the second pane (3), said at least one frame film (5) being provided between the at least one first connecting film (2) and the at least one second connecting film (4) so as to directly contact same and having a cut-out (8) such that a receiving space (13) is formed by the cut-out (8), said at least one first connecting film (2), at least one second connecting film (4), and at least one frame film (5) consisting of one or more thermoplastic materials, said thermoplastic material having a first phase transition temperature or said plurality of thermoplastic materials having a maximum first phase transition temperature, a transition of the thermoplastic material(s) from a solid state to a plastic state taking place at or above said first phase transition temperature, - a functional insert part (6) which has a planar shape and which has a first main surface (9), a second main surface (10), and an edge surface (11) running therebetween, said functional insert part (6) being positioned in the receiving space (13) in such a way that one main surface (9, 10) of the functional insert part rests directly against the at least one first connecting film (13) or against the at least one second connecting film (14), - a phase-changing layer (7) which is provided in the receiving space (13) in such a way that the phase-changing layer rests directly against the respective other main surface (9, 10) of the functional insert part (6), said phase-changing layer (7) having no direct contact with the at least one frame film (5) such that a compensation space (14) is formed between the phase-changing layer (7) and the at least one frame film (5), said phase-changing layer (7) consisting of a material which has a second phase transition temperature, a transition of the material of the phase-changing layer from a solid or gel-like state to a plastic or liquid state taking place at or above said second phase transition temperature, said second phase transition temperature being higher than the first phase transition temperature, b) carrying out a first laminating process of the layer stack (15) by evacuating and heating at least regions of the layer stack (15) in the region of the frame film (5) to a temperature at or above the first phase transition temperature and below the second phase transition temperature, and c) carrying out a second laminating process of the layer stack (15) by applying pressure and heating the layer stack (15) to a temperature at or above the second phase transition temperature.

Description

Method for producing a composite pane with a functional insert

The invention lies in the technical field of industrial pane production and relates to a method for producing a composite pane with a functional insert, a composite pane produced in particular by the method according to the invention and the use thereof.

Laminated panes typically consist of two panes and a thermoplastic interlayer that firmly bonds (laminates) the two panes together. The thermoplastic interlayer is typically made from one or more thermoplastic bonding films (also known as laminating films), particularly PVB films. Laminated panes are generally manufactured by autoclaving, where the panes are bonded together via the thermoplastic bonding films at elevated temperature and high pressure.

It is known to provide a composite pane with a functional insert embedded in the thermoplastic intermediate layer. Functional inserts are designed, for example, in the form of electro-optical functional elements. These are planar structures with electrically controllable optical properties of an active layer. This means that the optical properties of the active layer, and in particular its transparency and scattering behavior, can be controlled by an applied electrical voltage. Examples of electro-optical functional elements are SPD functional elements (SPD = Suspended Particle Device), which are known, for example, from EP 0876608 B1 and WO 2011033313 A1, and PDLC functional elements (PDLC = Polymer Dispersed Liquid Crystal), which are known, for example, from DE 102008026339 A1.

Functional inserts are laminated between two thermoplastic bonding films, usually of equal thickness. To compensate for the difference in thickness, a thermoplastic frame film can be used. This frame film is inserted between the two thermoplastic bonding films and surrounds the functional insert. Thus, the functional insert is inserted into a cutout in the frame film, with the functional insert surrounded like a passe-partout to protect it from excessive mechanical stress during the lamination of the laminated glass. For example, WO 2007/122428 A1 uses two thermoplastic connecting films made of PVB with a thickness of 0.76 mm and a frame film made of PVB with a thickness of 0.38 mm to integrate an SPD functional element into a composite pane. WO 2007/122429 A1 describes the same structure for liquid crystal-based functional elements.

Although the use of a frame film can significantly reduce the mechanical stress on the functional insert, the lamination of the laminated pane places mechanical stress on the functional insert, particularly when curved panes are laminated, which is often the case. In particular, the two panes may have different curvatures due to production tolerances or because this is desired. This can lead to reversible but also irreversible defects in the functional insert, such as a damaged active layer. Certain functional inserts can also be particularly sensitive to mechanical stress, such as photovoltaic modules integrated into the laminated pane, which can break during lamination.

EP 4242181 A1 discloses an intermediate film structure for a laminated pane.

In contrast, the object of the present invention is to provide an improved method for producing composite panes with integrated functional inserts. The composite panes should be easy, cost-effective, and reliable to produce in large quantities in industrial series production with high optical quality and low waste.

These and other objects are achieved according to the invention by a method for producing a composite pane according to the independent patent claim. Advantageous embodiments of the invention are set forth in the subclaims. A composite pane produced in particular by the method according to the invention and its use are set forth in the subordinate patent claims.

According to the invention, a method for producing a composite pane with an integrated functional insert is shown, wherein the functional insert is integrated into the composite pane, ie it is located between the two individual panes of the composite pane. The functional insert is a physical (flat) component that is inserted between the connecting foils used during the production of the composite pane.

The procedure includes the following steps, which are carried out in the specified order according to alphabetical designation:

Step a)

A layer stack is produced, which contains a first pane (e.g., a glass pane) and a second pane (e.g., a glass pane). The panes each have two surfaces (main surfaces) intended for viewing and, in particular, arranged substantially parallel to one another, as well as an edge surface extending between them. The first pane has a first surface I and a second surface II. The second pane has a third surface III and a fourth surface IV.

The layer stack further contains at least one first connecting film made of a thermoplastic material and at least one second connecting film made of a thermoplastic material. Furthermore, the layer stack contains at least one frame film (frame-shaped film) made of a thermoplastic material.

According to the invention, a single first connecting film or a plurality of first connecting films and/or a single second connecting film or a plurality of second connecting films and/or a single frame film or a plurality of frame films can be provided in the layer stack. If there are several first connecting films, there is a stacked arrangement of first connecting films. The first connecting films are preferably arranged in direct contact with one another. If there are several second connecting films, there is a stacked arrangement of second connecting films. The second connecting films are preferably arranged in direct contact with one another. If there are several frame films, there is a stacked arrangement of frame films. The frame films are preferably arranged in direct contact with one another.

According to the invention, at least one first connecting film is understood to mean a single first connecting film or a stacked arrangement of first connecting films. At least one second connecting film is understood to mean a single second connecting film or a stacked arrangement of second connecting films. Accordingly, at least one frame foil is to be understood as a single frame foil or a stacked arrangement of frame foils

The at least one frame film has a cutout which is delimited in the plane of the at least one frame film by the thermoplastic material of the at least one frame film, i.e. the cutout is an internal cutout of the at least one frame film. The at least one first connecting film and the at least one second connecting film are arranged between the first pane and the second pane in direct contact with them. The at least one frame film is arranged between the at least one first connecting film and the at least one second connecting film in direct contact with them. In the layer stack, in the stacking direction, the cutout of the at least one frame film is delimited by the at least one first connecting film (on one side of the at least one frame film) and by the at least one second connecting film (on the other side of the at least one frame film), thereby creating a receiving space.

The at least one first connecting film, the at least one second connecting film and the at least one frame film each consist of a thermoplastic material.

The at least one first connecting film, the at least one second connecting film, and/or the at least one frame film can be made of different thermoplastic materials. Alternatively, the at least one first connecting film, the at least one second connecting film, and the at least one frame film can be made of the same thermoplastic material. The thermoplastic material(s) each serve to adhesively bond the panes, i.e., they exhibit adhesive properties.

The thermoplastic material is characterized by a temperature, referred to here and hereinafter as the "phase transition temperature," at which the material changes from a solid state to a plastic state due to an increase in temperature. Below the phase transition temperature, the thermoplastic material is dimensionally stable (solid). At or above the phase transition temperature, the thermoplastic material is no longer dimensionally stable, i.e., plastic. In the plastic state, the thermoplastic material is softened or viscous, in particular, flowable. For easier reference and differentiation from a phase transition temperature of the phase change layer (see below), the Phase transition temperature of the thermoplastic material referred to here and hereinafter as "first phase transition temperature".

Different thermoplastic materials typically exhibit different first phase transition temperatures. Films made of thermoplastic materials in direct contact bond adhesively at or above the highest first phase transition temperature of the thermoplastic materials involved.

If the at least one first connecting film, the at least one second connecting film, and the at least one frame film are made of the same thermoplastic material, this thermoplastic material exhibits a first phase transition temperature. Below the first phase transition temperature, the thermoplastic material of all films is in a solid state. At or above the first phase transition temperature, the thermoplastic material of all films is in a plastic, i.e., softened, in particular, flowable, state and is no longer dimensionally stable.

If the at least one first connecting film, the at least one second connecting film, and the at least one frame film consist of several (i.e., two or more) different thermoplastic materials, these thermoplastic materials have different first phase transition temperatures, with a first phase transition temperature being a highest phase transition temperature compared to the other first phase transition temperatures. At or above the highest first phase transition temperature, the thermoplastic materials of all films are in a plastic, i.e., softened, in particular flowable, state and are no longer dimensionally stable.

A functional insert is arranged as a flat body in the cutout of the at least one frame foil. The functional insert has two surfaces or main surfaces, namely a first main surface and a second main surface, which are arranged essentially parallel to each other, as well as an edge surface extending between them.

It is understood that the cutout of the at least one frame foil is dimensioned sufficiently large so that the functional insert element can be arranged within the cutout. Furthermore, the thickness of the frame foil is selected to be greater than the thickness of the functional insert, measured in the stacking direction of the layer stack. The cutout of the at least one frame foil or the resulting receiving space is therefore larger than the functional insert. Consequently, the functional insert does not fit precisely into the cutout of at least one frame foil or receiving space.

A layer, referred to here and hereinafter as the "phase change layer," is also arranged in the cutout of the at least one frame foil or receiving space. The cutout of the at least one frame foil or receiving space is dimensioned sufficiently large so that, in addition to the functional insert, the phase change layer can be arranged within the cutout.

The functional insert is arranged in the cutout of the at least one frame film such that its first main surface lies directly (flat) against the at least one first connecting film or its second main surface lies directly (flat) against the at least one second connecting film. Thus, the functional insert lies directly (flat) against one main surface of the at least one first connecting film or the at least one second connecting film. The phase change layer lies directly (flat) against the other main surface of the functional insert. In the stacking direction, the functional insert and the phase change layer are arranged flat above or below one another.

The phase change layer preferably has no direct contact with the at least one frame foil, whereby a cavity, hereinafter referred to as "compensation space" for ease of reference, is formed between the phase change layer and the at least one frame foil.

The phase change layer consists of a material characterized by a temperature, referred to here and hereinafter as the "phase transition temperature," at which the material, upon temperature increase, transitions from a solid or gel-like state to a plastic or liquid state. In particular, the material of the phase change layer transitions from the solid or gel-like state to a liquid state. For ease of reference and to distinguish it from the first phase transition temperature of the thermoplastic material, the phase transition temperature of the material of the phase change layer is referred to as the "second phase transition temperature." In the solid or gel-like state below the second phase transition temperature, the material At or above the second phase transition temperature, the material is no longer dimensionally stable, i.e., plastic or liquid.

At the first phase transition temperature and at the second phase transition temperature, a phase transition of the materials involved occurs. Thus, when heated, the thermoplastic material undergoes a phase transition, the order of which depends essentially on the degree of crystallinity of the thermoplastic material, which can be crystalline, semi-crystalline, or amorphous. At the first phase transition temperature, the thermoplastic material softens, changing from a solid state to a plastic state, particularly a viscous or flowable state. At the second phase transition temperature, the material of the phase change layer changes state from solid or gel-like to plastic or liquid, particularly to liquid.

In one embodiment of the method according to the invention, the first phase transition temperature is a melting temperature of the thermoplastic material, wherein the transition from solid to soft, i.e., from solid to plastic, or viscous or flowable, is considered melting of the thermoplastic material. In accordance with the first phase transition temperature, the melting temperature is referred to as the first melting temperature. Similarly, the second phase transition temperature is a melting temperature of the material of the phase transition layer, wherein the transition from solid or gel-like to liquid is considered melting of the material. In accordance with the second phase transition temperature, the melting temperature is referred to as the second melting temperature.

The phase transition of the thermoplastic material and the phase transition of the material of the phase-change layer can be determined conventionally, e.g., by DSC (differential scanning calorimetry). The phase transition can be detected by a sudden or continuous change in material parameters. This method is well known and familiar to those skilled in the art, so it need not be explained in detail here. Suitable equipment for performing DSC is commercially available from various manufacturers.

In a crystalline material undergoing a first-order phase transition, the phase transition is characterized by a temperature. In a semi-crystalline or amorphous material, however, the phase transition (e.g., softening of the thermoplastic material) occurs within a temperature range. If the phase transition of a If a thermoplastic material is characterized by a temperature range, the first phase transition temperature within the meaning of the present invention can be any temperature within the temperature range at which the phase transition occurs, for example, the lowest temperature, the highest temperature, or the average temperature within the temperature range. This applies accordingly to several thermoplastic materials.

In one embodiment of the method according to the invention, the thermoplastic material of the at least one first connecting film, the at least one second connecting film, and the at least one frame film has a viscosity at or above, in particular at, the second phase transition temperature that is higher than the viscosity of the material of the phase-change layer. This viscosity can be determined using commercially available viscometers.

It is essential that the second phase transition temperature of the material of the phase change layer is higher than the or highest first phase transition temperature of the thermoplastic material(s) of the connecting foil(s) and the at least one frame foil.

In step a), the phase-change layer is in a solid or gel-like state. The at least one first connecting film, the at least one second connecting film, and the at least one frame film are in a solid state.

Step b)

In this process step, a first lamination or pre-lamination of the layer stack produced in step a) takes place, wherein the layer stack is evacuated and heated at least partially (i.e. only locally) in the region of the at least one frame film to a temperature at or above the first phase transition temperature, but below the second phase transition temperature. The layer stack is pre-laminated in order to adhesively bond the at least one first connecting film, the at least one second connecting film and the at least one frame film and to seal the receiving space. The thermoplastic material(s) of the connecting films and the at least one frame film are converted from a solid state into a softened, in particular flowable or viscous, state, so that the films of thermoplastic material that are in direct contact form an adhesive bond. The compensation space can be partially decomposed by the thermoplastic material(s). The phase change layer remains in a solid or gel-like state in step b), since the The layer stack is heated to a temperature below the second phase transition temperature. Preferably, the layer stack is heated over its entire surface in step b) (i.e., not just locally, but across the entire surface of the wafers).

Step c)

In this process step, a second lamination or final lamination of the layer stack already pre-laminated in step b) takes place, wherein the layer stack is subjected to pressure and heated to a temperature at or above the second phase transition temperature. During the final lamination of the layer stack, the layers of the layer stack are firmly bonded to one another. In this process, the material of the phase change layer is brought into a plastic or liquid state, advantageously into a liquid state, and fills the compensation space. In step c), the films made of a thermoplastic material are in a softened, in particular flowable or viscous, state. The phase change layer is in a plastic or liquid state, advantageously a liquid state. Advantageously, the viscosity of the films made of a thermoplastic material at (and optionally also above) the second phase transition temperature is greater than the viscosity of the material of the phase change layer. This is the case, for example, if the films made of a thermoplastic material are in a softened or viscous state in step b) and the material of the phase-change layer is in a liquid state in step b). The composite pane is produced in step c).

During the initial lamination of the layer stack in step b), it is possible that damage may occur to the functional insert due to mechanical stress, particularly due to the high forces during evacuation of the layer stack. This damage may be visible defects such as deformations, bubbles, etc.

The term "phase change layer" is based on the property of the material of the phase change layer to be in a solid or gel-like state (i.e. dimensionally stable state) during the first lamination or pre-lamination of the layer stack in step b) and to be in a plastic or liquid state (i.e. non-dimensionally stable state), in particular in a liquid state, during the second lamination or final lamination of the layer stack in step c), i.e. to be in different phase states in steps b) and c). In contrast to this, the thermoplastic material of the films in steps b) and c) is in a plastic state, i.e. in no different phase states. In other words, only the phase-change layer is in different phase states in steps b) and c).

As the inventors have surprisingly discovered, the damage to the functional insert is reversible and can be reduced or even eliminated during the second lamination (final lamination) of the layer stack in step c) through a combination of elevated temperature and external pressure. Without being bound to any theory, it is currently assumed that the phase-change layer in step c) exerts only a low mechanical load on the functional insert in the liquid (or optionally plastic) state, with the liquid (or optionally plastic) material of the phase-change layer depleting the compensation space in step c). In this way, damage to the functional insert can be healed by applying pressure and heating. The method according to the invention can be carried out in the industrial series production of laminated panes using conventional production equipment. These are major advantages of the method according to the invention, since laminated panes with an integrated functional insert can be produced simply, cost-effectively, and reliably in large numbers with high optical quality and low waste.

According to one embodiment of the method according to the invention, the functional insert is arranged in the cutout of the frame foil such that it has no direct contact with the frame foil. This measure has the advantage that the compensation space is expanded by the space between the functional insert and the at least one frame foil. The compensation space is thus composed of the space between the phase-change layer and the at least one frame foil and the space between the functional insert and the at least one frame foil. In step c), the liquid material of the phase-change layer can thus also flow into the space between the functional insert and the at least one frame foil. Mechanical stress on the functional insert can thus be even better avoided.

The functional insert is arranged in the cutout of the at least one frame foil such that it directly (flatly) contacts one main surface of the at least one first connecting foil or the at least one second connecting foil. The phase-change layer directly (flatly) contacts the other main surface of the functional insert. According to one embodiment of the method according to the invention, the phase-change layer of the at least one connecting foil, which is opposite the other main surface of the functional insert, lies directly against it. This measure enables simple production of the composite pane and, at the same time, provides good mechanical protection for the functional insert in step c) during the second lamination or final lamination of the layer stack.

The at least one first connecting film, the at least one second connecting film, and the at least one frame film consist of one or more thermoplastic materials, which according to one embodiment are selected from polyvinyl butyral (PVB), ethylene vinyl acetate (EVA), and thermoplastic polyurethane (TPII). The aforementioned materials PVB, EVA, and TPII are preferred because they are frequently used and widely accepted in the automotive industry, and the use of conventional production equipment is at least partially possible. Furthermore, these materials are cost-effective.

The material of the phase-change layer can, in principle, be chosen arbitrarily, as long as it is guaranteed that the material is transparent and has a second phase-change temperature that is higher than the first phase-change temperature of the thermoplastic material(s). Furthermore, the material of the phase-change layer must be chemically and mechanically compatible with the thermoplastic material(s).

At the first phase change temperature of the thermoplastic material(s), the material of the phase change layer is in solid or gel-like form. In step b), the material of the phase change layer is thus in solid or gel-like form. In step c), the material of the phase change layer is in plastic or liquid form, in particular in liquid form.

It is understood that the second phase change temperature of the material of the phase change layer must not be so high that the thermoplastic material decomposes and the functional insert experiences thermal damage in step c). Preferably, the second phase change temperature of the material of the phase change layer is above the first phase change temperature of the thermoplastic material(s) of the connecting foil(s) and at least one frame foil, up to a value selected from 200°C, 180°C, 160°C, 140°C, 120°C, 100°C, 80°C, 60°C, 40°C, 30°C, and 20°C. For example, in step b), the layer stack is heated to a maximum temperature of 100 °C. In particular, the first phase change temperature of, for example, PVB is below 100 °C. For example, in step c), the layer stack is heated to a maximum temperature of 110 °C, 120 °C, or 130 °C. For example, PVB remains viscous.

Preferably, the thermoplastic material of the connecting films and the at least one frame film is in viscous form in step b) and in step c). Preferably, the material of the phase change layer is in solid or gel-like form in step b) and in liquid form in step c). Preferably, the thermoplastic material of the connecting films and the at least one frame film is in viscous form in step c) and the material of the phase change layer is in liquid form in step c). Preferably, the thermoplastic material of the connecting films and the at least one frame film is in viscous form in step c) and the material of the phase change layer is in viscous form in step c), wherein the viscosity of the thermoplastic material of the connecting films and the at least one frame film is greater than the viscosity of the material of the phase change layer.

According to one embodiment of the method according to the invention, the phase-change layer contains or consists of a microcrystalline wax or an ionomeric thermoplastic resin, preferably in combination with PVB as the thermoplastic material for the connecting films and the at least one frame film. However, other materials, such as thermoplastics, are also conceivable.

In particular, a microcrystalline wax can be in gel form (microcrystalline wax gel). Microcrystalline wax can be gelled using suitable additives, e.g., polyethylene glycol-8 beeswax. The exact composition can be selected depending on the specific application. The ionomeric thermoplastic resin is, for example, an ethylene-methacrylic acid copolymer with zinc (Zn), sodium (Na), lithium (Li), or other metal ions, which is commercially available from DuPont under the trade name "Surlyn." This material is particularly characterized by transparency, hardness, chemical resistance, and a low phase transition temperature (melting temperature).

The material of the phase change layer can be, for example, an optically clear adhesive. Optically clear adhesives (OCA) are known to those skilled in the art as These are well known and can be purchased commercially from a variety of suppliers. Optically clear adhesives are characterized by high optical quality with high light transmission and low-distortion transparency. They are particularly common where a virtually invisible adhesive layer is required, for example in displays or touch panels. Optically clear adhesives are often used in touch-sensitive displays, for example to connect them to an LCD display or to connect plastic covers to touch-sensitive displays. The optically clear adhesive can, for example, contain or consist of polyurethane (PU), polyacrylate, silicone, epoxies or a copolymer or mixture thereof. The optically clear adhesive is advantageously made of a casting resin, particularly one based on polyurethane or silicone.

The optically clear adhesive is curable, meaning it can be irreversibly cured. Typically, it is a plastic that is cured into a polymer-crosslinked state. This distinguishes the optically clear adhesive significantly from a thermoplastic material, which, while also optically transparent, can always be softened and, in particular, made flowable again (i.e., reversibly) through the application of heat. In contrast, the optically clear adhesive can no longer be softened and, in particular, made flowable once it has cured. The optically clear adhesive is therefore not a thermoplastic.

Depending on the type of optically clear adhesive, curing can occur through thermal curing (i.e., application of heat), through electromagnetic radiation, particularly UV radiation, IR radiation, or microwave radiation, through ultrasound, through the application of moisture, or through a chemical reaction between different components (particularly two-component adhesives). The time required for curing of the optically clear adhesive can be influenced by temperature in many curing processes. In particular, curing can be accelerated by applying heat. Conversely, curing can be slowed by cooling. The time required for curing can therefore be controlled, for example, by heating or cooling the optically clear adhesive.

According to one embodiment of the method according to the invention, in step b) the layer stack in the area of the frame foil is heated only locally, in particular by local Exposure to the stack of layers with hot air and/or local electrical heating of the frame film. This measure has the advantage of saving time and money in sealing the cavity.

According to one embodiment of the method according to the invention, in step b) the layer stack is heated over its entire surface, which can have process-engineering advantages.

For the purposes of this invention, the term "lamination" refers to the creation of a strong adhesive bond under the influence of heat, vacuum, and/or pressure. Known methods for producing a laminated pane can be used.

Vacuum laminators, in particular, can be used for step b). These laminators consist of one or more heated and evacuatable chambers in which the glass panes are laminated over a period of, for example, approximately 60 minutes at a reduced pressure of 0.01 mbar to 800 mbar and a temperature of 80°C to 170°C. Conventional vacuum bag or vacuum ring processes, for example, operate at approximately 200 mbar and 80°C to 110°C.

For example, lamination in step c) is carried out by autoclaving at an elevated pressure of approximately 10 to 15 bar and temperatures of 130°C to 145°C for a period of, for example, two hours. Pressing in a calender between at least one pair of rollers is also possible. The temperature during the pressing process is, for example, between 40°C and 150°C. Combinations of calendering and autoclaving processes have proven particularly effective in practice.

The lamination of composite panes has been described many times in the patent literature and is well known to those skilled in the art from the industrial series production of composite panes as a standard process, so that it need not be discussed in more detail here.

The functional insert is a planar body. In principle, the insert can be designed in any desired manner, as long as its use in the composite pane according to the invention is possible and technically feasible. According to a preferred embodiment of the method according to the invention, the functional insert is an electro-optical functional element with electrically controllable optical properties, in particular an SPD functional element, a functional element based on liquid crystal technology, in particular a PDLC functional element, or an electrochromic functional element, a light source or a light guide or a photovoltaic module.

The method according to the invention is particularly advantageous for electro-optical functional films with a liquid crystal-based phase-change layer based on the so-called "guest-host" effect. These typically comprise a nematic liquid crystal (host) provided with an additive (guest), wherein, for example, dichroic dye molecules that absorb light anisotropically are used as the additive. Since the molecules of the additive have an elongated shape, their orientation can be controlled by the orientation of the molecules of the liquid crystal, i.e., the host. This is achieved in practice by applying an electric field to the liquid crystal. In this way, for example, the optical transparency of the guest-host film can be very precisely controlled by an external electric field. For example, windshields can be very advantageously provided with an electrically switchable transparency similar to a sun visor.

As practice has shown, guest-host films, due to their physical properties resembling a liquid, are very sensitive to mechanical stress caused by uneven contact pressure. Even the smallest local deviations in contact pressure during lamination of the laminated pane and in the laminated composite pane lead to the appearance of local optical defects in the guest-host films, which can render the composite pane unusable.

Guest-host films are well known to those skilled in the art, so they need not be discussed in detail here. Guest-host films are commercially available, for example, under the term "light control film," for example, from Dai Nippon Printing Co., Ltd., Japan, under the product name LCF005(EU). The electro-optical functional film is preferably a guest-host film.

The invention also extends to a composite pane which is preferably, but not necessarily, produced by the method according to the invention.

The composite pane comprises a layer stack containing a first pane (e.g. glass pane) with a first surface I and a second surface II and a second pane (e.g. glass pane) with a third surface III and a fourth surface IV, wherein the The first pane and the second pane are firmly connected to each other via an intermediate layer.

The intermediate layer comprises at least one first connecting film made of a thermoplastic material, which is firmly connected to the second surface II, at least one second connecting film made of a thermoplastic material, which is firmly connected to the third surface III, and at least one frame film (frame-shaped film) made of a thermoplastic material, which is located between the first connecting film and the second connecting film and is firmly connected to them in direct contact. The at least one first connecting film, the at least one second connecting film and the at least one frame film are adhesively connected to one another and can at least conceptually be identified as layer-like or ply-like regions in the intermediate layer. The at least one frame film is located between the at least one first connecting film and the at least one second connecting film.

The at least one frame foil has a cutout that forms a receiving space delimited by the at least one first connecting foil and the at least one second connecting foil. A functional insert is accommodated in the receiving space. Furthermore, a phase-change layer is accommodated in the receiving space. Thus, the functional insert and the phase-change layer are embedded in the intermediate layer.

The functional insert is accommodated in the cutout or receiving space such that its first main surface directly abuts the at least one first connecting film or its second main surface directly abuts the at least one second connecting film, so that one main surface of the functional insert directly abuts the at least one first connecting film or the at least one second connecting film. The phase-change layer is accommodated in the cutout or receiving space such that it directly abuts the other main surface of the functional insert, wherein the phase-change layer also has direct contact with the at least one frame film.

The at least one first connecting film, the at least one second connecting film and the at least one frame film consist of one or more thermoplastic materials, wherein the one thermoplastic material has a first phase transition temperature or the plurality of thermoplastic materials have a highest first phase transition temperature, wherein at or above the first phase transition temperature a transition of the thermoplastic material(s) from a solid state to a plastic state occurs. The phase-change layer consists of a material having a second phase transition temperature, wherein at or above the second phase transition temperature, a transition of the material of the phase-change layer occurs from a solid or gel-like state to a plastic or liquid state, in particular to a liquid state, wherein the second phase transition temperature is higher than the first phase transition temperature.

According to one embodiment of the composite pane according to the invention, the phase change layer lies directly against the at least one connecting film which is opposite the other main surface of the functional insert.

According to one embodiment of the composite pane according to the invention, the phase change layer is arranged between the edge surface of the functional insert and the at least one frame foil in direct contact with them.

According to one embodiment of the composite pane according to the invention, the phase change layer lies directly on the at least one first connecting film and the at least one second connecting film.

Measured in the stacking direction, in the region of the functional insert, i.e., in a region where the phase-change layer directly abuts the other main surface of the functional insert, a thickness of the at least one frame foil is equal to or greater than a combined thickness of the functional insert and the phase-change layer. Preferably, a thickness of the at least one frame foil is equal to a combined thickness of the functional insert and the phase-change layer.

According to one embodiment of the composite pane according to the invention, the at least one first connecting film, the at least one second connecting film and the at least one frame film consist of one or more thermoplastic materials selected from polyvinyl butyral (PVB), ethylene vinyl acetate (EVA) and thermoplastic polyurethane (TPU). According to one embodiment of the composite pane according to the invention, the phase change layer contains or consists of a microcrystalline wax, an ionomeric thermoplastic resin, a thermoplastic plastic or an optically clear adhesive.

The panes of the composite pane contain or consist of glass, particularly preferably flat glass, float glass, quartz glass, borosilicate glass, aluminosilicate glass, soda-lime glass, or of clear plastics, preferably rigid clear plastics, in particular polyethylene, polypropylene, polycarbonate, polymethyl methacrylate, polystyrene, polyamide, polyester, polyvinyl chloride, and/or mixtures thereof. Suitable glasses are known, for example, from EP 0 847 965 B1. Preferably, the two panes are made of glass, particularly preferably of soda-lime glass, as is customary for window panes.

The panes can be clear, tinted, or colored. If the laminated pane is used as a windshield, it should 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 and the second pane can also be referred to as the outer and inner panes.

The first pane and the second pane may have other 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 pane and the second pane can vary widely and thus be adapted to the requirements of the individual case. The first pane and the second pane advantageously have standard thicknesses of 0.7 mm to 25 mm, preferably of 1.4 mm to 2.5 mm for vehicle glass and preferably of 4 mm to 25 mm for furniture, appliances and buildings, in particular for functional radiators. The size of the panes can vary widely and depends on the size of the use according to the invention. The first and the second pane have areas of 200 ^cm² to 20 ^m², which are typical in vehicle construction and architecture, for example.

In the context of the present invention, "transparent" means that the total transmission of the laminated pane complies with the legal requirements for windscreens and front side windows and preferably has a transmittance of more than 70%, and especially more than 75%. Accordingly, "opaque" means a light transmission of less than 5%, especially 0%.

The laminated glazing can be designed to separate an interior space from the outside environment in an opening in a building or a window opening in a vehicle.

Furthermore, the invention extends to the use of the composite pane according to the invention on buildings or in means of transport for traffic on land, in the air or on water, in particular in motor vehicles, for example as a windscreen, rear window, side window and/or roof window, in particular in a passenger car or lorry, preferably as a roof window in a motor vehicle.

The various embodiments of the invention can be implemented individually or in any combination. In particular, the features mentioned above and explained below can be used not only in the specified combinations, but also in other combinations or on their own, without departing from the scope of the present invention.

The above statements in connection with the method according to the invention for producing a composite pane apply analogously to the composite pane according to the invention. Similarly, the statements in connection with the composite pane according to the invention apply analogously to the method according to the invention for producing a composite pane.

The invention is explained in more detail below using exemplary embodiments, with reference to the accompanying figures. They show, in simplified, schematic representations, not to scale:

Figure 1 shows a cross section through an embodiment of the composite pane according to the invention,

Figure 2 shows a cross-section through an intermediate product for producing the composite pane of Fig. 1, Figure 3 shows a cross-section through another intermediate product for producing the composite pane of Fig. 1,

Figure 4 is a flow chart of the process for producing a composite pane.

Consider first Figure 1, which illustrates an embodiment of the composite pane according to the invention in cross-section. The section is parallel to the stacking direction of the composite pane.

The composite pane, designated overall by the reference numeral 100, comprises a first pane 1 with a first surface I and a second surface II, and a second pane 3 with a third surface III and a fourth surface IV. In the composite pane 100, the second surface II and third surface III face one another. The first surface I and the fourth surface IV face away from one another and form the outer surfaces of the composite pane 100. The first pane 1 can also be referred to as the outer pane, and the second pane 3 as the inner pane. The two panes 1, 3 are made, for example, of soda-lime glass and have a thickness of, for example, 1.4 mm to 2.5 mm. The composite pane 100 is intended here, for example, as a transparent windshield or roof window of a motor vehicle.

The first pane 1 and the second pane 3 are firmly connected to one another via an intermediate layer 12. The intermediate layer 12 can, at least conceptually, be divided into various layered regions, which are referred to as "films" depending on their production. Thus, the intermediate layer 12 comprises a first connecting film 2 made of a thermoplastic material, which is firmly connected to the second surface II, a second connecting film 4 made of a thermoplastic material, which is firmly connected to the third surface III, and a frame film 5 made of a thermoplastic material, which is located between the first connecting film 2 and the second connecting film 4 and is firmly connected to them in direct contact. The first connecting film 2, the second connecting film 4, and the frame film 5 are adhesively connected, with the first connecting film 2 being located above the frame film 5 and the second connecting film 4 being located below the frame film 5 when stacked in the direction of gravity. The first connecting film 2, the second connecting film 4 and the frame film 5 consist of polyvinyl butyral (PVB), ethylene vinyl acetate (EVA) and/or thermoplastic polyurethane (TPII). The frame film 5 has an inner cutout 8 which is delimited by the first connecting film 2 and the second connecting film 4 and forms a receiving space 13.

The intermediate layer 12 further comprises a functional insert 6, which is received in the cutout 8 or receiving space 13. The functional insert 6 is flat and has a first main surface 9 and a parallel second main surface 10, between which the edge surface 11 is located. The first main surface 9 and the second main surface 10 face away from one another. The functional insert 6 is arranged within the cutout 8 or receiving space 13 such that its first main surface 9 is in direct contact with the first connecting film 2 and no direct contact with the second connecting film 4. Furthermore, the functional insert 6 does not have direct contact with the frame film 5 within the receiving space 13, but is spaced apart from the frame film 5.

The intermediate layer 12 further comprises a phase-change layer 7, which is received in the cutout 8 or receiving space 13 such that it directly abuts the second main surface 10 of the functional insert 6. The phase-change layer 7 has direct contact with the frame foil 5 and directly abuts the second connecting foil 4, which lies opposite the second main surface 10 of the functional insert 6. Furthermore, the phase-change layer 7 is arranged between the edge surface 11 of the functional insert 6 and the frame foil 5 in direct contact with them, which is possible because the functional insert 6 does not extend to the frame foil 5. As can be clearly seen in Figure 1, the phase-change layer 7 directly abuts the first connecting foil 2 and the second connecting foil 4, with the phase-change layer 7 having direct contact with the first connecting foil 2 in the area where the functional insert 6 does not have direct contact with the first connecting foil 2. The phase-change layer 7 surrounds the functional insert 6 in a frame-like manner at its edge surface 11. Measured in the stacking direction, in the region of the functional insert 6, i.e., in a region where the phase-change layer 7 directly abuts the second main surface 10 of the functional insert 6, the thickness of the frame foil 5 is equal to the combined thickness of the functional insert 6 and the phase-change layer 7.

The receiving space 13 is formed inside the intermediate layer 12. The functional insert 6 and the phase-change layer 7 are embedded in the intermediate layer 12. The functional insert 6 is, for example, an electro-optical functional element, such as an SPD functional element, PDLC functional element or preferably a guest-host foil.

The phase change layer 7 contains or consists of a microcrystalline wax, an ionomeric thermoplastic resin, a thermoplastic plastic or an optically clear adhesive.

The production of the composite pane 100 shown in Figure 1 is illustrated below using an exemplary embodiment of the method according to the invention. Consider first Figure 2, which illustrates a cross-section of an intermediate product for producing the composite pane 100 of Figure 1.

Accordingly, a layer stack 15 is produced in which the first pane 1, the first connecting film 2, the second pane 3, the second connecting film 4, and the frame film 5 are stacked one above the other. The frame film 5 has the cutout 8, which, together with the first connecting film 2 and the second connecting film 4, forms the receiving space 13. The functional insert 6 and the phase-change layer 7 are accommodated in the receiving space 13.

The functional insert 6 rests directly with its first main surface 9 against the first connecting film 2 and is spaced apart from the frame film 2. The phase change layer 7 rests directly against the second main surface 10 of the functional insert 6 and the second connecting film 4, but has no contact with the frame film 5 or is spaced apart from it. This forms a compensation space 14 delimited by the functional insert 6, in particular its edge surface 11, by the phase change layer 7, by the first connecting film 2 and the second connecting film 4, and by the frame film 5. The compensation space 14 is a region of the receiving space 13 and extends (in a frame-like manner) circumferentially around the functional insert 6 and the phase change layer 7.

The layer stack shown in Figure 2 is subjected to a first lamination (pre-lamination) to form an adhesive bond between the first connecting film 2 and the second connecting film 4, each with the frame film 5. This can be done, for example, in a vacuum laminator. Here, the layer stack 15 is evacuated to a temperature above the first phase transition temperature of the The thermoplastic materials of the first connecting film 2, the second connecting film 4, and the frame film 5 are heated, the temperature remaining below the second phase transition temperature of the material of the phase-change layer 7. The thermoplastic material(s) thereby melt or soften in order to adhesively bond the first connecting film 2 and the second connecting film 4 to the frame film 5 and to seal the receiving space 13.

In one embodiment, the layer stack 15 is heated over its entire surface, i.e. over the entire surface of the panes 1, 3. In an alternative embodiment, the layer stack 15 is only heated locally in the region of the frame film 5, in particular by locally exposing the layer stack 15 to hot air and/or locally electrically heating the frame film 5. For example, the layer stack is heated to a maximum temperature of 100°C if PVB is used as the thermoplastic material, wherein the melting point of PVB is below 100°C. The phase change layer 7 remains in a solid or gel-like state and can exert a certain mechanical pressure on the functional insert 6 in order to adhesively bond it to the first connecting film 2. This can be done, for example, in a vacuum laminator.

Figure 3 illustrates a cross-section of another (later) intermediate product for producing the composite pane 100 of Figure 1. Accordingly, the layer stack 15 undergoes a second lamination (final lamination), wherein the layer stack 15 is heated to a temperature above the second phase transition temperature of the material of the phase-change layer 7, which thereby becomes liquid. Furthermore, the layer stack 15 is subjected to external pressure. Thus, the layer stack is autoclaved. This can be done, for example, in an autoclaving device.

As illustrated in Figure 3 by the arrows, the liquid material of the phase-change layer 7 flows into the compensation space 14, which completely collapses, so that only a slight mechanical pressure is exerted on the functional insert 6. Any defects in the functional insert 6 that were created in step b) during the first lamination of the layer stack 15 can be reduced or even healed by the second lamination in step c). For example, the layer stack 15 is heated in step c) to a maximum temperature of 110 °C, 120 °C, or 130 °C. PVB used as a thermoplastic material then remains viscous. For example, the layer stack 15 is subjected to a pressure of 5 bar. Figure 4 shows a flow chart of the method for producing the composite pane 100 of Figure 1.

Step a)

Producing a layer stack 15, containing a first pane 1 with a first surface I and a second surface II and a second pane 3 with a third surface III and a fourth surface IV, wherein the second surface II and the third surface III face each other, a first connecting film 2, a second connecting film 4 and a frame film 5, which are arranged between the first pane 1 and the second pane 3, wherein the frame film 5 is arranged between the first connecting film 2 and the second connecting film 4 in direct contact with them and has a cutout 8, so that a receiving space 13 is formed by the cutout 8, wherein the first connecting film 2, the second connecting film 4 and the frame film 5 consist of one or more thermoplastic materials, wherein a phase transition temperature of the thermoplastic material or a highest phase transition temperature of the plurality of thermoplastic materials is a first phase transition temperature, a functional insert 6 with a flat shape, which has a first main surface 9 and a second main surface 10, as well as an edge surface 1 1 running therebetween, wherein the functional insert part 6 is arranged in the receiving space 13 such that it lies directly against one main surface 9, 10 of the first connecting film 13 or the second connecting film 14, a phase change layer 7 which is arranged in the receiving space 13 such that it lies directly against the other main surface 9, 10 of the functional insert part 6, wherein the phase change layer 7 has no direct contact with the frame film 5, so that a compensation space 14 is formed between the phase change layer 7 and the frame film 5, wherein the phase change layer 7 consists of a material with a phase transition temperature which is a second phase transition temperature, wherein the second phase transition temperature is higher than the first phase transition temperature.

Step b)

First lamination of the layer stack 15 by evacuating and at least partially heating the layer stack 15 in the area of the frame film 5 to a temperature of or above the first phase transition temperature and below the second phase transition temperature.

Step c)

Second lamination of the layer stack 15 by applying pressure and heating the layer stack 15 to a temperature at or above the second phase transition temperature.

From the above, it can be seen that the invention provides an improved method for producing composite panes with integrated functional inserts, by which the composite panes can be produced with high optical quality and low waste due to comparatively low mechanical stress on the functional inserts. The method can be implemented in the industrial series production of composite panes in conventional production facilities, allowing composite panes with high optical quality and low waste to be produced in large numbers simply, cost-effectively, and reliably.

Reference symbol:

1 first slice

2 first connecting foil

3 second slice

4 second connecting foil

5 frame foil

6 functional insert

7 Phase change layer

8 Excerpt

9 first main area

10 second main area

11 Edge surface

12 Intermediate layer

13 Recording room

14 Compensation room

15 layer stacks

100 composite panes

I first surface of the first disc

II second surface of the first disc

III third surface of the second disc

IV fourth surface of the second disc

Claims

Claims 1. A method for producing a composite pane (100) with a functional insert (6), comprising the following steps: a) producing a layer stack (15) containing a first pane (1) with a first surface (I) and a second surface (II) and a second pane (3) with a third surface (III) and a fourth surface (IV), wherein the second surface (II) and the third surface (III) face each other, at least one first connecting film (2), at least one second connecting film (4) and at least one frame film (5) which are arranged between the first pane (1) and the second pane (3), wherein the at least one frame film (5) is arranged between the at least one first connecting film (2) and the at least one second connecting film (4) in direct contact with these and has a cutout (8) such that a receiving space (13) is formed by the cutout (8), wherein the at least one first connecting film (2), the at least one second connecting film (4) and the at least one frame film (5) are made of one or consisting of several thermoplastic materials, wherein one thermoplastic material has a first phase transition temperature or the several thermoplastic materials have a highest first phase transition temperature, wherein a transition of the thermoplastic material(s) from a solid state to a plastic state occurs at or above the first phase transition temperature, a functional insert (6) with a flat shape, which has a first main surface (9) and a second main surface (10), as well as an edge surface (11) running between them, wherein the functional insert (6) is arranged in the receiving space (13) such that it directly adjoins one main surface (9, 10) of the at least one first connecting film (13) or the at least one second connecting film (14), a phase change layer (7) which is arranged in the receiving space (13) such that it directly adjoins the other main surface (9, 10) of the functional insert (6), wherein the phase change layer (7) has no direct contact with the at least one frame film (5), such that a compensation space (14) is formed between the phase change layer (7) and the at least one frame foil (5), wherein the phase change layer (7) consists of a material having a second phase transition temperature, wherein at or above the second phase transition temperature a transition of the material of the phase change layer from a solid or gel-like state into a plastic or liquid state, wherein the second phase transition temperature is higher than the first phase transition temperature, b) first lamination of the layer stack (15) by evacuating and at least partially heating the layer stack (15) in the region of the frame film (5) to a temperature at or above the first phase transition temperature and below the second phase transition temperature, c) second lamination of the layer stack (15) by applying pressure and heating the layer stack (15) to a temperature at or above the second phase transition temperature. 2. Method for producing a composite pane (100) according to claim 1, wherein the functional insert (6) is arranged in the receiving space (13) such that it has no direct contact with the frame film (5). 3. A method for producing a composite pane (100) according to claim 1 or 2, wherein the phase change layer (7) in step a) directly adjoins that at least one connecting film (4) which lies opposite the other main surface (10) of the functional insert (6). 4. A method for producing a composite pane (100) according to one of claims 1 to 3, wherein the phase change layer (7) after step c) has direct contact with the at least one frame film (5). 5. A method for producing a composite pane (100) according to one of claims 1 to 4, wherein the phase change layer (7) after step c) has direct contact with the at least one first connecting film (2) and direct contact with the at least one second connecting film (4). 6. A method for producing a composite pane (100) according to one of claims 1 to 5, in which the phase change layer 7 after step c) is arranged between the edge surface (1 1 ) of the functional insert (6) and the at least one frame film (5) in direct contact with these. 7. A method for producing a composite pane (100) according to one of claims 1 to 6, in which in step b) the layer stack (15) in the area of the frame foil (5) is locally is heated, in particular by locally applying hot air to the layer stack (15) and/or locally electrically heating the at least one frame film (5). 8. A method for producing a composite pane (100) according to one of claims 1 to 6, wherein in step b) the layer stack (15) is heated over its entire surface. 9. A method for producing a composite pane (100) according to one of claims 1 to 8, wherein the at least one first connecting film (2), the at least one second connecting film (4) and the at least one frame film (5) consist of polyvinyl butyral (PVB), ethylene vinyl acetate (EVA) and/or thermoplastic polyurethane (TPU), and/or the phase change layer (7) contains or consists of a microcrystalline wax, an ionomeric thermoplastic resin, a thermoplastic plastic or an optically clear adhesive, and/or the functional insert (6) is an electro-optical functional element (6), in particular an SPD functional element, a functional element based on liquid crystal technology, in particular a PDLC functional element, an electrochromic functional element or a guest-host functional film. 10. Composite pane (100), in particular produced by the method according to one of claims 1 to 9, comprising a first pane (1) with a first surface (I) and a second surface (II) and a second pane (3) with a third surface (III) and a fourth surface (IV), wherein the second surface (II) and the third surface (III) face each other, at least one first connecting film (2), at least one second connecting film (4) and at least one frame film (5) which are arranged between the first pane (1) and the second pane (3), wherein the at least one frame film (5) is arranged between the at least one first connecting film (2) and the at least one second connecting film (4) in direct contact therewith and has a cutout (8), wherein a receiving space (13) is formed by the cutout (8), wherein the at least one first connecting film (2), the at least one second connecting film (4) and the at least one frame film (5) consist of one or more thermoplastic materials, wherein the one thermoplastic material has a first phase transition temperature or the plurality of thermoplastic materials have a highest first phase transition temperature, wherein at or above the first phase transition temperature a Transition of the thermoplastic material(s) from a solid state to a plastic state occurs, a functional insert (6) with a flat shape, which has a first main surface (9) and a second main surface (10), as well as an edge surface (11) running therebetween, wherein the functional insert (6) is arranged in the receiving space (13) such that it directly adjoins one main surface (9, 10) of the at least one first connecting film (13) or the at least one second connecting film (14), a phase change layer (7) which is arranged in the receiving space (13) such that it directly adjoins the other main surface (9, 10) of the functional insert (6), wherein the phase change layer (7) consists of a material having a second phase transition temperature, wherein at or above the second phase transition temperature a transition of the material of the phase change layer from a solid or gel-like state to a plastic or liquid state occurs, wherein the second phase transition temperature higher than the first phase transition temperature. 11. Composite pane (100) according to claim 10, wherein the phase change layer (7) is arranged between the edge surface (11) of the functional insert (6) and the at least one frame foil (5) in direct contact therewith. 12. Composite pane (100) according to one of claims 10 or 11, wherein the phase change layer (7) of the at least one connecting film (4) which lies opposite the other main surface (10) of the functional insert (6) lies directly against. 13. Composite pane (100) according to one of claims 10 to 12, wherein the phase change layer (7) is in direct contact with the at least one first connecting film (2) and the at least one second connecting film (4). 14. Composite pane (100) according to one of claims 10 to 13, wherein the at least one first connecting film (2), the at least one second connecting film (4) and the at least one frame film (5) consist of polyvinyl butyral (PVB), ethylene vinyl acetate (EVA) and/or thermoplastic polyurethane (TPU), and/or the phase change layer (7) contains or consists of a microcrystalline wax, an ionomeric thermoplastic resin, a thermoplastic plastic or an optically clear adhesive, and/or the functional insert (6) is an electro-optical functional element (6), in particular an SPD functional element, a functional element based on liquid crystal technology, in particular a PDLC functional element, an electrochromic functional element or a guest-host functional film. 15. Use of the composite pane (100) according to one of claims 10 to 14 on buildings or in means of transport for traffic on land, in the air or on water, in particular in motor vehicles, for example as a windshield, rear window, side window and/or roof window, preferably as a roof window.