DE9103824U1 - Multilayer thermoplastic film - Google Patents

Description

Description of the film and the process for its production:

Transparent, opaque white and colored thermoplastic films are used to replace opaque varnish as a coating for covering fibrous materials, wood parts, plastics and metals, etc. These films should have a sticky side and a surface that is mechanically highly resilient and partly chemical-resistant and that adheres to a wide range of materials. According to the current state of the art, these films are colored opaquely by a coating of dispersion- or solvent-based adhesives and paints. A disadvantage has been found to be that the bond between the color layer and the carrier layer of the biaxially oriented and thermally fixed film based on polyester, polypropylene and polyamide has only a low adhesion, especially over a longer period of time. The coating of an adhesive with or without pigments applied to the outer film sometimes splits shortly after use and bubbles and wrinkles form. Furthermore, the adhesive on one of the outer surfaces is often already active at room temperature, so that when the two adhesive sides come into contact with each other, an adhesion occurs and the film becomes unusable for further use. The adhesion of the adhesive is limited in the variety of possible surfaces, in particular for surfaces made of metal or glass. A much better adhesion of the adhesive and color pigments applied to the outer film layer is only possible by additionally applying a first adhesive, usually containing aggressive solvents and substances, as a base layer to the film to be coated, sometimes known as a primer, which prepares the surface for the adhesion of the following sticky and colored layer. The solvents applied with the pigments and the adhesive are almost impossible to remove later. The practice of a simple odor test shows that despite the greatest expenditure on machinery and energy, it is not possible to really completely remove the fast-reacting solvents applied with the coating from the coating. Experts speak of a "solvent sump ^11" which is formed by the surface becoming encrusted by heat drying, comparable to a surface closure when the coating compound is not completely dried. If the alternative is to apply a layer of paint to transparent or colored film using a system of rollers, as is usual with rotary printing machines, the film's lacquer-like opacity cannot be achieved. Depending on the type, application and printing medium, printing inks contain a quantity of 39% - 78% solid pigments and can only be applied to a web with low weights (grams/m2). If this web is coated several times, the opacity does not reach the opaque value required by the user. The upper limit of coloring by printing lies in the acceptance of the color application on a web that has already been colored by printing and the hardness of the film resulting from the addition of the color layers. If the weight of the color application is too great, some of the color will flake off. The upper limit of the color application is usually limited to 6.0 g/m2 to 10 g/m2 pigment content in the layer. If the film is not

shrinks rather than stretches, the statically solid ink film, either printed or applied as a mass, tears off and ugly holes form. The process is expensive and, depending on the type of web to be printed, solvents are required.

The invention consists in producing a multilayered film, optionally transparent or colored, with an extremely high proportion of pigments, with at least 4 layers, a surface that is highly temperature-resistant and resistant, and another open, sticky side. The structure of the film is shown in the drawing "Figure 1" and is described as follows:

(1) shows the oriented layer of the thermoplastic film, (Xl) shows a thermoplastic layer resting on the layer (1),

(2) shows the layer of a laminating adhesive, (X2) shows the layer of a thermoplastic,

(3) shows a transparent or optionally opaque colored layer,

(4) shows the layer of polymeric thermoplastic adhesive,

(5) shows the layer of a separating layer acting against layers (1) and (4).

Layers (1) and (4) form the outer surface of the finished usable film. Layer (5) lies on layer (4) with little adhesion and is not connected to it.

Experience has shown that the amount of pigments added to the film during the extrusion process ends at a value of 6% to 10% by weight. The newly discovered process and the heavily pigmented film itself enable the optional production of a layer (3) filled with a large proportion of color pigments or covering materials, and this layer can be drawn into a 2- or 4-layer film. Extrudable polymers are used as carriers for the pigments instead of the usual solvents and binding agents. The shorter extrusion route and subsequent secure lamination using a polyurethane-based adhesive for connecting the individual layers to produce the multi-layer film becomes possible.

The separating layer, which is later applied separately in existing coating techniques, can be produced in the new process, depending on the structure of the layers, at the same time as the other layers (X2), (3) and (4) using the CO extrusion process, so that only a residual amount of adhesive bond remains between the separating layer (5) and the other co-extruded layers, which allows the separating layer (5) to be easily removed from the later finished film. Tests have shown a value of max. 120 grams, measured at an angle of 90 degrees at a removal speed of 100 mm/min, for a 15 mm wide film strip.

For the production of this film, some known processes are required, such as extrusion, bi-axial orientation, CO-extrusion, and lamination. The adjustable adhesive strength of the layer (4) against a variety of

Materials, without the separating layer (5) extruded at the same time in most combinations achieving too great an adhesion, which makes it difficult or even impossible to remove the separating layer (5) from the other films, makes the film usable. What is new is that the film, preferably equipped with a high proportion of a dye, can be produced and as a film has a high opacity similar to that of a lacquer. If this film is co-extruded with another polymer adhesive, the film is obtained that can be bonded with heat, the economic and practical use of which is only possible after lamination with a more temperature-resistant and mechanically resistant thermoplastic oriented film that repels many chemicals. The process enables the properties of polymers to be used and thus production to be free of solvents.

An extruded thermoplastic film, optionally monoaxially or biaxially oriented and thermally fixed, is used as the film for layer (1). Depending on the type, its stretch values range from 2x2 times = 4 times to 7x8 times = 56 times. The materials available for layer (1) are predominantly films based on polyester, preferably 12 my to 23 my thick, polypropylene, preferably 15 my to 30 my thick, and polyamide, preferably 15 my to 30 my thick. The polymers for layer (1) can also consist of a CO polymer, such as a CO polyester, a CO polypropylene and a CO polyamide. In the case of CO polyamide, a type that contains proportions of polyamide 6 and polyamide 6.6 is preferably used. For applications that are subject to high mechanical stress, polyamide types are particularly recommended, and are available in a wide range. Other extrudable polymers with other properties are also suitable for layer (1).

A monoaxially oriented film should also be used for layer (1), which has been stretched at least 2 to 56 times in one direction, i.e. 1-axis. This film is more advantageous if the film to be glued is placed around the part in a similar way to a banderol, the film is fixed with the adhesive side on the surface to be glued and the length of the circumference of the film is shortened by shrinking after it has been wrapped. The layer (4) provided with the thermoplastic adhesive adheres to the glued surface and also to layer (1).

The free choice of polymers for layer (1) also allows for further individual finishing of the film. Variants are described towards the end of the document.

A free choice of the highly active adhesive of layer (2) also allows other orientable plastics for production, so that the ideal material combination for the respective application can be freely and very safely selected.

A number of plastics used for the layer (1) are characterized by a adhesion to their surface

repellent behavior. To eliminate these disadvantages, a highly effective adhesive is required to permanently and highly resiliently bond the following layer (3) to layer (1). The best experience here has been with a layer of 1- and 2-component adhesives, preferably based on polyurethane, applied in a thin layer (2) of 1.0 g/m to max. 10 g/m2, preferably 1.5 g/m2 to 2.5 g/m2. Adhesives are also available that are made on the basis of polyesters and epoxies by reacting them with acrylates. As the length of the molecular chains / size of the molar weight increases, the adhesion of the adhesive increases in proportion, so that the range of selectability of the adhesion of layer (2) to other layers is very secure. The requirements for adhesion to layer (1) must be optimally met in relation to the application of the finished film.

The layers that come into contact with the laminating adhesive layer (2), preferably a polyurethane adhesive, are corona treated to ensure the adhesion of the adhesive to layer (2). The corona treatment affects layers (1), (X2) and (3). The corona treatment achieves a surface tension of the film of 28 to 48 dynes, preferably 40 dynes, for the secure adhesion of the laminating adhesive to the surfaces.

The extruded film, which has at least two layers, is laminated with the corona-treated surface of layer (3) against the film of layer (1) coated with a 1- or 2-component laminating adhesive, preferably the adhesive based on a polyurethane. This can be done at room temperature or warm.

A film with at least 2 layers, preferably a 3 or 4 layer film, is then manufactured separately from thermoplastic polymer materials using CO extrusion. The CO extrusion process is based on the fact that at least one separate extruder per polymer, preferably 3 or 4 separate extruders, various polymer melts, which, depending on the structure of the melts of layers (3) and (4), are pressed into a mold or distributor tool designed for co-extrusion, which is guided as a T-shaped nozzle for the production of a flat film or as a ring nozzle for the production of a tubular film, and is formed into a film. The drawing "Figure 2" shows a mold as a blow head with a ring nozzle for the production of a 3-layer tubular film. The channels for feeding the polymers from the extruders are shown as 1 for layer (5), 2 for layer (3) and 3 for layer (4). 4 the exit of the polymer melt from the ring nozzle. It is preferable to combine the melts (5), (3) and (4) before exiting the tool, i.e. still within the tool, to form a single multi-layer layer.

As layer (3), a transparent or opaque colored polymer and another layer (4) of a thermoplastic adhesive and optionally a separating layer (5) are drawn into a multi-layer film in one operation. The flow behavior of the thermoplastic masses is determined by the melt index according to

ISO-R 292 and is between 0.2 and 60.0 g/minute, preferably in the range of 2.0 to 6.0 g/minute.

For the use of films that are very resistant to aging and are exposed to sunlight or permanently high temperatures, it is recommended that the film be made of polyamides or polyesters. In comparison to polyolefins, these are much more resistant to unfavorable conditions and are therefore more advantageous. It is advantageous to use a polyamide that is extruded transparently or colored for layer (3). Polyamide is a polymer that is very tough in the cold, notch-resistant and very resistant when used outdoors. Weather resistance is improved by muted coloring, so that several layers filled with carbon black are also advantageous. A favorable CO polyamide that can be used for low temperatures has the following characteristics: density according to DIN 53479, 1.06, melting range according to the DSC method 124 - 128 degrees C,

For layer (3), either a transparent polyethylene or one filled with pigments is available, preferably a low density polyethylene of 0.916 - 0.940 according to ASTM-D 1505. The polyethylene is used as a carrier. It remains available as an extrudable mass through additions such as additives or pigments. The filler weight proportions can be up to 80% of the mass of the total volume, in some cases up to 90%. For brightly colored films, a proportion of pigments in the polymer of 20% to 60% is recommended. A value of 20-80 my, preferably 45-60 my, has proven to be a favorable thickness of the pigmented layer. A further suitable carrier for layer (3) is CO-polyethylene with proportions of vinyl acetate of 0.1% to 30%, to which quantities of lubricants and anti-caking agents must be added.

Mineral substances are available as pigments, for the color white titanium dioxide (TI02), which can also be processed in types such as rutile white and anatase white. For colorful coloring, orange and inorganic colored pigments, which are available in a wide range on the market for extrusion, can be used. For optimal light protection, carbon black is recommended as a covering material. Inexpensive fillers such as chalk and other products are also possible.

For the film of layers (3) and (4), a monoaxially or biaxially oriented film is advantageous, especially if the shrinkage values specified by the orientation are to be adjusted to the other layers in parallel to the shrinkage values of the outer layer (1). If the layer (3) is tempered by orientation and optionally thermally fixed, its properties improve considerably and, depending on the value of the orientation, can achieve the properties known from the orientation.

Films with a very low reaction point when heated require a polymer for layer (3) whose Vicat softening point is below 80 degrees C. Preferably

Ionomers or EVA polyethylene are available, which can be used optionally. Such polymers are particularly advantageous for colored coverings that have an uneven substrate and in which the layer (1) can move away from the layer (3) without tension during the shrinking process and the layer (2) hangs on a remaining layer of the layer (3) and moves with the layer (1). This becomes clear with an example: The layer (1) is exposed to a temperature of 135 degrees C for the shrinking and reacts very quickly. Due to the low thermal conductivity of plastics, the heat flows too slowly through the layer (3) made of polyethylene, whose softening point according to Vicat is 92 degrees C. The dimensional stability of the layer (3) made of polyethylene still remains partially. The layer (1) shrinks, the layer (3) is not yet fully plastic and so compensation cannot yet take place or can only take place in part. Compensation for absolutely free shrinkage is possible if layer (3) has a Vicat softening point of e.g. 65 degrees C, so that this layer is highly viscous at the moment while layer (1) is shrinking.

The layer (3) itself can consist of several layers that differ in terms of the percentage of pigments, differences in the colors and the melt index. This means that an extremely highly pigmented layer (80% by volume) can be placed in the center of the layer (3), which proves to be very advantageous in the process.

The white or colored polymer, preferably polyethylene, is processed with a dispersant. This allows lower extrusion temperatures than would otherwise be possible, which in turn has a positive effect on the freer choice of polymers for the extrusion of the polymeric thermoplastic adhesive.

A CO-polypropylene based on ethylene-propylene-CO-polymer is also possible as a carrier for layer (3). If a polymer other than a polyolefin is used for layer (3) for certain applications, it may be necessary to enclose layer (3) by layers (X2) and (4).

The layer (4) of the thermoplastic adhesive, which is preferably made from polymers by the process of alloying/grafting, consists of CO or terpolymers, which are optionally based on amides (polyamide PA), ethylene (polyethylene PE) or propylene (polypropylene PP), ionomers, ethylene-vinyl acetate (EVA), synthetic wax, synthetic rubber, anhydride, maleic anhydride, acrylic, methacrylate, acrylonitrile, acids and other polymer groups. The thickness of this layer is 10-50 my, preferably 20-30 my.

The adhesive strength of the polymer thermoplastic adhesive (4) against the layer (1) is adjustable in terms of adhesion and surface smoothness, selectable from temperatures of 49 degrees C and more, so that at room temperature the film is not yet sticky and can be processed safely. The adhesive effect depends on the setting and

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the structure of the polymer against most thermoplastic masses possible, further against paper, fiber materials and with special settings also against metals and glass. The hot-adhesive ability of the polymer thermoplastic adhesive of layer (4) is determined by the temperatures to which the thermoplastic is exposed. This means that thermal windows can be selected in the thermal reaction of the adhesive, which at least during the formation of layer (4) increase or reduce the adhesion to other layers. These thermal windows are also important for the production of the film. The selectable adjustability of the hot adhesive strength of the adhesive softened by heat is an advantage compared to other processes, so that when the warm adhesive side comes into contact with the surface to be bonded or the outer layer (1) of the oriented film, an adhesive effect occurs under heat before the layers are bonded together by pressing. The thermoplastic adhesive has the advantage that the bonding point can be dissolved by reheating the adhesive layer (4), thus separating the surface layers and layer (1). This can be freely adjusted so that the separation can be achieved with little or no residue on the bonded surface.

The adhesion of the polymeric thermoplastic adhesive of layer (4) to layer (1) and other surfaces cannot be dissolved by moisture and in many cases also not by solvents, such as acetone, aqueous mixtures with isopropyl alcohol, etc.

The adhesion of the polymeric thermoplastic adhesive of layer (4) to other surfaces is determined by the diverse structure of the respective adhesive type through the process of alloying polymers and their chemical change. Polymers and polymeric acids contained in the thermoplastic adhesive attack other surfaces with increasing heat and thereby achieve adhesion. The CO-extrusion process and the large selection ^of "adhesive" substances in the thermoplastic adhesive provide a broad spectrum for adhesion to other surfaces. The adhesion of thermoplastic adhesives to other plastics is partly described below. On the other hand, extrudable polymers are available which form only a slight bond to the polymers of layer (4) and can be extruded with the thermoplastic adhesive using the co-extrusion process. The still hot melts of layers (4) and (5) are brought together in the blow head tool when heated or immediately after the melt emerges from the mold, known as the nozzle, without any bonding, only adhesion to one another. The layers (4) and (5) adhere to one another adhesively, so that a separating layer (5) can be produced when the material is selected. These layers can later be separated from one another by splitting and peeling them off.

The polymeric thermoplastic adhesives for a reaction of bonding the film with the surface of the layer (4) at temperature, depending on pressure and duration of heat exposure, lead to adhesion against polymers with proportions:

Adhesives that are determined by proportions of ethylene-vinyl acetate and other functional polymer groups adhere below 89 degrees C to polymer groups containing proportions of acrylic, acrylonitrile butadiene styrene (ABS), polystyrene (PS), polycarbonate (PC), polyvinyl chloride (PVC), polyvinylidene chloride (PVDC), polyester (PET), polypropylene (PP), polyethylene (PE), ethylene-vinyl acetate (EVA).

Adhesives that are determined by proportions of ethylene terephthalate based polymers and other functional polymer groups adhere to polymer groups with proportions of polyamides (PA), polyolefins, e.g. (PE, PP), aluminum (AL), printed surfaces at temperatures below 89 degrees C.

Adhesives that are determined by acrylate-based components and other functional polymer groups adhere to polymer groups with polyolefin components, such as polyethylene (PE), polypropylene (PP), as well as to aluminum (AL),

Thermoplastic adhesives at temperatures above 90 degrees C to 165 degrees C, depending on pressure and duration of heat exposure, with predominant components of:

Adhesives based on polyolefins, especially medium and high density polyethylene and polypropylene and other functional polymer groups for higher temperature stability, adhere to medium density polyethylene (MD-PE), high density polyethylene (HD-PE), CO-polypropylene (CO-PP), polypropylene (PP), polyurethane (PU), acrylic-based adhesives and paints, urethane-based adhesives and other polymer group-based thermoplastic adhesives for special application of corrosion-free bonding to metals such as steel, galvanized steel, tinned steel, chrome-plated steel, stainless steel, aluminum, brass, copper, magnesium, nickel and to glass and glassy surfaces at lower temperatures.

Other combinations are possible against which the thermoplastic adhesives adhere, their components are adjusted to the adhesion of the other surface.

The development of thermoplastic adhesives is advanced. Polymer thermoplastic adhesives based on polyamide can be produced for particularly high heat-resistant applications. It is expected that new developments in adhesive strength, effect on surfaces and temperatures will increase the use of these adhesives. Adhesives can be available for temperatures below 49 degrees C. Adhesives can also be based on polyesters or polyamides as a carrier and are then characterized by their higher heat resistance up to 260 degrees C.

All adhesives adhere to fibrous materials such as textiles, wood and paper at temperatures of 49 degrees C and more.

To produce the layer (4) as a film, temperatures are sometimes required for a few types of application of the polymer thermoplastic adhesive which, due to the high adhesive strength when heated, cause the polymer thermoplastic adhesive to stick to the layer (5) and thus the separating layer (5) cannot be removed from the layer (4) or can only be removed with difficulty. In this case, a layer (5) equipped with a separating agent is applied to the layer (4), which later enables the layers (4) to be easily separated from the layer (5) when the film is removed.

The additives added to the polymeric thermoplastic adhesive of layer (4) in the form of spacers and lubricants migrate to the surface of layer (4) after extrusion and migrate through layer (5) to its surface. A film consisting of the spacers and lubricants forms on the surfaces. The additives preferably used are lubricants, lubricants based on erucic or oleic acid amides, spacers as anti-blocking agents based on, for example, highly dispersed synthetic silica to eliminate this adhesion. The grainy structure of the additives of the spacer with a diameter of optionally 1-3 my creates the grainy surface that eliminates the "glass plate effect" otherwise defined as adhesion or bonding. If two smooth surfaces are pressed against each other without air in between, comparable to two glass plates, these surfaces adhere to each other. Only when air gets between the layers do the layers fall apart. Lubricants based on erucic or oleic acid amides and antiblocking agents based on highly dispersed synthetic silica can be added to the oriented film of layer (1) or the co-extruded layer (X2), (3), and (4) that comes into contact with layer (2). The friction coefficient according to ASTM D 1894 can be up to a factor of 0.4 thanks to these additives.

Alternatively, it is possible to add another layer (Xl) or (X2) directly between layers (1) and (2) or between layers (2) and (3). If this layer is between layers (1) and (2), it is referred to as layer (Xl); if it is between layers (2) and (3), it is referred to as layer (X2). This layer can consist of a coating or a polymer plastic. Its function is to enable layer (1) to slide more freely and thus less stressed onto layer (3) during thermal processing when forming round or smaller parts in particular, during the dimensional change resulting from the different shape/surface.

In the case of a coating, the layer (Xl) can be made of the polymeric materials polyvinyl chloride (PVC), polyvinylidene chloride (PVDC), polyvinylidene chloride/acrylic, polyacrylitrile (PAN), polymethacrylic resin, chlorinated polymers based on ethylene and propylene, such as chlorinated polyethylene, chlorinated ionomer, chlorinated polypropylene and other paintable materials whose softening point according to Vicat ASTM-D 1525 is at least 15 degrees C less than the softening point according to Vicat ASTM-D 1525 for the

Layer (3). Solvent-based adhesives, known as primers, are required for the paint to adhere to layer (1) if paints are used whose molecular structure does not bond to layer (1). If the molecular chains of the paint bond to the molecular chains of layer (1), primers are not required. Experience has shown that the paint has a thickness of 1 my to 3 my, preferably around 1 my. The disadvantages of painting are the usually poor adhesion to layer (1) and the use of solvents, and this method should therefore be rejected.

If, on the other hand, the layer (1) is bonded to the polymer of an ionomer that is better for the function by applying a hot melt from a slot nozzle, adhesives are also used, either as solvent-containing primers, solvent-free adhesives or preferably thermoplastic meltable adhesion promoters, which enable the ionomer to adhere to the layer (1). In this case, chlorinated polymers and solvents are avoided. The melted layer (Xl) reaches a thickness of 5 my to 10 my, preferably 5 my. It is conceivable to apply the ionomer as a layer (Xl) as a finished film, for which the ionomer as a film usually reaches a thickness of around 20 my and adhesives based on polyurethane are again required for adhesion to the layer (1).

It is very advantageous to use a thermoplastic for the layer (X2) whose softening point according to Vicat is 15 degrees C lower than the temperature point at which the layer (1) begins to shrink. Preferably, a polymer with a predominantly ionomer content that has a softening point according to Vicat ASTM-D 1525 of less than 96 degrees C, preferably a value between 55 and 75 degrees C, is suitable. At the same time, this polymer develops sticky properties against the layer (3) in direct contact when heated.

The CO extrusion process makes it possible to dispense with the multitude of adhesives and processes described above as dispersion and solvent-based processes and to extrude layer (X2) at the same time as layers (3), (4) and (5). In this case, lubricants based on oleic acid or erucic acid amides, preferably 50 - 6000 ppm, and anti-caking agents, preferably 50 - 8000 ppm, are added to the mass of polymers for layers (X2) and (3). The amount of lubricants and anti-blocking agents is determined by the material structure of the layers. "PPM" means "parts per million".

If the activation of the polymeric thermoplastic adhesive of layer (4) is set for a reaction over a range of 49 degrees C and the layer (4) contains a sufficient amount of spacers in the form of lubricants and anti-caking agents, the separating layer (5) can be dispensed with in some cases. When the film is wound up, the layer (4) comes into direct contact with the layer (1) without any adhesion or slight sticking of the layer (4) to the layer (1).

The functional separating layer (5) can be extruded at the same time as layers (3) and (4) with a large number of possible types and kinds of thermoplastic adhesive for layer (4), whereby the adhesive bond between the layers does not exceed the value of 120 grams of weight of a 15 mm wide film strip peeled off at a speed of 100 mm/minute at an angle of 90 degrees. This has been proven by a test with polymers of special mixtures. When selecting the polymer materials for layers (4) and (5), the polymer materials must be selected according to the choice and structure of the polymers and the application of the film in order to achieve the required "bonding" and adhesive bonding effects for peeling off the separating layer (5).

The thickness of the layer (5) can be freely selected from 5 my to 50 my, preferably in a range from 5 my to 20 my.

Polymers that do not adhere to the thermoplastic adhesive of layer (4) are recommended for layer (5), even when exposed to heat. Similar to the effect of two smooth glass plates lying on top of each other, adhesion still occurs, which is partially introduced into layer (5) by adding spacers, known as anti-blocking agents, and thus reduces the adhesive adhesion to a reasonable residual value. The separating layer (5) created in this way can be selected in a thickness of 10 my to 40 my, preferably 10 my - 20 my. The layer (5) can be peeled off from the finished film, consisting of layers (1), (2), (X2), (3) and (4). The following combinations of materials are preferred: layer (4) against a polyamide, preferably a CO-polyamide, layer (4) against a polyurethane and others. Adhesion for these combinations with a selection of the appropriate additives and temperatures for extrusion is only slightly adhesive. Due to the high strength of polyamide/CO-polyamide and polyurethane, the thickness of the layer (5) can be chosen to be very low, preferably 5-10 my thick, and is still fully functional.

If an internally acting release agent is mixed into the polymer of layer (5), there is no adhesion of layers (4) to layer (5) after extrusion. These release agents act immediately and migrate to the surface of layer (5). There they form a film that prevents adhesion. They neutralize layer (4) of the polymer thermoplastic adhesive so that layer (5) can later be easily removed from layer (4). The more crystalline the polymer of layer (5) is, the slower the migration of the internal release agents. The residual adhesion of the release layer (5) to layer (4) changes into an adhesive behavior. This is particularly advantageous in the process of co-extruding layers (X2), (3), (4) and (5) in one operation. These films, which are equipped with an internally acting release agent, can also be fed as a separate film immediately before the film, consisting of layers (X2), (3) and (4), is wound up and in this case form a cumbersome

other type of production. A disadvantage is that the internal release agents migrate into the layer (4) over time and affect its adhesive properties.

The separate introduction of a separating layer (5) is possible. External separating agents can be used for layer (5). Layer (5) is provided with an external separating agent that adheres to its surface and can optionally be based on PTFE coatings, silicones and other materials. At the same time, a film of layer (5) can be introduced as a cooled film layer against the surface of a just extruded and cooled film layer consisting of layers (3) and (4) before they are wound up, so that adhesion of layers (4) and (5) to one another due to heat above 49 degrees C is not possible. For such processes, the method of producing a flat film using a T-extrusion die is advantageous, because the layers (X2), (3) and (4) on the first extruder and the layer (5) on the second extruder can be produced and cooled at the same time and layered against each other by bringing the film webs together.

The process and the film produced using it make it possible to equip the polymer layers with additional additives that can be freely selected depending on the application in a targeted and highly effective manner, thus further improving the quality of the film's application. The ideal additives can be added very easily to layers (X2), (3) and (4) and also specifically to layer (1), without having to accept functional and thus quality reductions by mixing these additives in a single layer. The following additives are possible:

Stabilizers are built in to prevent damage from light/UV light. They prevent the molecular structure from deteriorating, so that the material can be exposed to light for longer than usual.

For use in areas where there is constant heat, it is advantageous to equip the film with thermal stabilizers. This will ensure that the film can be used for longer when exposed to heat.

If the film is to be used indoors, it is recommended that the film be made flame-retardant. To achieve this, additives can be incorporated into all important layers.

The thermoplastic behavior of all layers, except for layer (2), opens the way to many applications. The material of layer (1) preferably always consists of polymers whose thermal fixation point is significantly higher than the temperature point at which layers (X2), (3) and (4) are already sticky or whose shrinkage has already occurred. When the film shrinks, layer (1) develops an extremely high shrinkage force in comparison to the non-oriented layers (X2), (3) and (4), which causes the already soft layers (X2), (3) and (4) to shrink.

The less temperature-resistant layers (X2), (3) and (4) inevitably change with the dimension of layer (1). The layer (2) changes parallel to layer (1). This is clearly visible in the example of the thermal behavior of layer (1).

If a film is only made from layers (X2), (3) and (4) with an optional layer (5) and these layers are not oriented, this film can be used despite the missing layer (1) depending on the structure of the polymers. There are applications for which "space" must remain for an anistotropic stretching through the following processing and treatment processes, be it through deformation at low temperatures or heat processes. If the film consisting of layers (X2), (3) and (4) with a low stretching - i.e. not fully oriented - is used for these applications, this coating still means a significant improvement in the properties through orientation. This is particularly beneficial for long-term applications because the properties for mechanical resistance, temperature stability and stability through radiation are improved.

Description of values and methods for data:

Melting point of the polymer

preferred polymers of layer (1)

polyester
thermal
fixed not fixed

265C 265C

Polypropylene thermally fixed not fixed

from 158 C - 164 C

Value of orientation (increase in surface area in the semi-plastic temperature range)

18 to 48x

up to 50 times

Thermal fixation for short-term heat

Onset of shrinkage Temperature Degrees C Time for shrinkage Shrinkage area/ Dimension change

210C - 140C

150 C 70-110 C 120 C 30 min. immediately 5 min. 1.5% 30%-45% 3%-4%

75-135C

immediately

40%-60%

Depending on the density and CO content, polyethylene becomes plastic according to Vicat ASTM-D 1525 in the range that begins at 75 degrees C and ends at 135 degrees C, depending on the structure of the polymer and its density. A polyethylene with a density of 0.922 according to ASTM-D 1505 has a Vicat softening point according to ASTM-D 1525. If a polymer with low temperature stability is used for layer (3), the temperature point that triggers the shrinkage of layer (1) can easily be identified, at which layer (1), which determines the shrinkage stress, changes the dimensions of all layers.

Preferably, a polymer is used for the layer (3) whose Vicat softening point is 15 degrees C below the temperature point at which the layer (1) loses its dimensional stability.

With thermally fixed polypropylene, the melting point and the point at which the polymer becomes plastic (i.e. the film burns through) are very close to each other. The difference is only 10-15 degrees C depending on the type. This means that polymer thermoplastic adhesives with a bonding point of around 50 - 70 degrees C are very advantageous here because the user is hardly able to determine the duration and temperature precisely.

If a film is glued onto the finished film with surface layers (1) and (4) and this should remain dimensionally stable, it is recommended to use layer (1) made of a thermally fixed polyester or polyamide. Polyester in particular is temperature-stable up to 210 degrees C for a short time, so that the film is unlikely to warp.

If the temperature value for thermal fixation of the film is exceeded, the thermal stability achieved by the fixation "collapses" and the film shrinks quickly by a high percentage. The graph "Figure 3" clearly shows the thermal behavior of a bi-axially oriented polyester film that has not been thermally fixed. The vertical column on the left 1 with the numbers from 0 to 50 shows the value of the simultaneous shrinkage of the film, the horizontal bar below 2 with the numbers from 60 - 100 shows the temperature required for the shrinkage in degrees C.

The effect of the shrinkability of layer (1) can be used excellently because the hot adhesive strength of the thermoplastic adhesive of layer (4) can be adjusted over a wide thermal range and the bonding at temperatures of around 49 degrees C and more initially bonds the entire adhesive surface and when the change in dimensional stability is triggered by shrinking or expanding, the entire film must adapt to the shapes to which the adhesive layer has bonded the film. The shrinkage strength of layer (1) is usually lower than the hot adhesive strength of the layer (4) connected as a surface, depending on the surface.

The layer (3) of a polyethylene loses its dimensional stability from temperatures in the core of the mass, depending on the density of the material, preferably from 88 degrees C to 135 degrees C. The difference can therefore always be set to a value that is at least 15 degrees C to the point at which the layer (1) begins to lose its dimension, i.e. either shrinks or, depending on the value of the orientation, expands/enlarges in the surface when large forces are applied. The same applies to polypropylene and CO-polypropylene, which achieves thermal stability up to degrees C depending on the proportion of ethylene in the molecular chains.

The film produced in this way can easily be used to wrap or cover flat, large, square or curved surfaces and then bond them using heat radiation and shrink them if necessary. In most cases where shrinkage of the surface of the film is desired, this can only be achieved with an oriented layer (1). On the other hand, the expansion of the surface when the layer (1) is heated can be achieved with a layer (1) that is not fully oriented. The expansion corresponds to an orientation. The use of a monoaxially oriented layer (1) is limited in practice.

The oriented and thermally fixed layer (1) remains smooth when heat is absorbed up to a value that is stable below the temperature point for thermal fixation. If this value is exceeded, a dimensional change occurs due to the forces released by the film of all layers. The triggering of the hot adhesive force at low heat makes it possible to keep the temperature point during processing for the adhesion of the layer (4) to smooth and flat surfaces low and only when the thermal adhesive force has fully occurred can the film be subsequently shrinked or its surface expanded. If you want to cover round or curved surfaces, simply heat the film beyond the value of thermal fixation and start the shrinkage. If the value of the orientation of layer (1) and the expansion of layers (Xl), (X2), (3) and (4) is set low, an expansion of the film surface can be achieved, comparable to an orientation. If the shrinkage of the film, triggered by layer (1), is to be achieved at a lower temperature, a thermally non-fixed oriented film must be used as layer (1), the layers (X2), (3) and (4) of which must also be oriented in relation to layer (1).

An interesting application is the possible expansion of the film when heated into a room with lower atmospheric pressure. The hot-melt adhesive strength of layer (4) can initially be used at lower temperatures to ensure very good adhesion to the outer edge / the flat area around the cavity. If the heat is now brought above the value of the thermal fixation of layer (1) and there is a negative pressure in the cavity, the surface of the film expands and clings to the inner surface of the cavity. The expansion of the film has a similar effect to an orientation for layer (1). At the same time, layer (4) is bonded to the inner surface of the cavity. The coating is finished.

First, the thermoplastic adhesive layer (4) adheres to the contact surface, be it the surface to be coated/bonded or be it the layer (1). An overlap with the adhesive layer (4) on the layer (1) is achievable and the two outer sides (1) and (4) can be bonded together using heat and pressure.

The extremely high hot-melt adhesive properties of the polymeric thermoplastic adhesive of layer (4) also enable further processing

processing the film by pressing it with heat or blowing it with hot air or warm pressing parts or cloths, without the overlapping point where the outer surfaces of the layers (1) and (4) come into contact with each other dissolving or becoming distorted by the pull of the shrinkage.

The ability to absorb the adhesive side (4) on the outer oriented (stretched) film of the layer (1) further enables other films to be glued there, either to apply a different color or to repair a damaged area.

Since the 1950s, decorative films have been produced using front printing on the basis of coloured hard or soft PVC. Some of these films have been used to lay out panels as flooring in cupboards. Anyone who has ever laid out such a floor board will be annoyed with their work after 6 months at the latest. The film wrinkles, warps, attracts dust due to static and is absolutely unattractive. On the other hand, if the new film is glued to the edges of the panel with heat using an iron and then shrunk with a hot air dryer, activating the thermoplastic adhesive at the same time, you will see the advantage of the new film. And PVC can be avoided when used in interior rooms where there is a risk of fire.

It is very popular to stick a vacuum-metallized film to another surface without shrinking it. This creates a brilliant, reflective look that would otherwise never be possible. The brilliant, optically optimal mirror shine of these films is only possible with a surface of the layer (1) that is covered from the outside and the layer (4) securely adhering to the surface to be glued. This is of the utmost importance for graphic applications, e.g. for lettering and areas on advertising posters. Alternatively, a transparent layer (1) can be printed as a contrast, e.g. with a lettering that is protected by the following finishing steps and is enclosed in the film in a way that is almost impossible to destroy. Or, much more simply, a lettering made from an opaque colored film can be glued to the already mounted metallized layer using heat. These metallic effects are inexpensive to produce. The metallic effects, such as aluminum, silver, gold, copper, etc., are determined by the choice of the vapor deposition under vacuum and subsequent coloring. The conductivity of electricity, depending on the metal evaporated in the vacuum, can also occur between the layers. For this purpose, a polyester film is recommended as layer (1) with a thickness of at least 125 my, which consists of a 137 my layer and a 12 my thick metallized layer connected by means of a polyurethane adhesive.

Sheet metal can be coated with coloured foils either to avoid previous painting or to apply a required decoration.

Another application of the film is the renovation of existing colored surfaces. Colorful paints, whether painted or otherwise applied,

lose their brilliant effect in the light and fade. The pigments incorporated into the film also have this property. However, removing these faded areas is much easier when using the film, because the coating only needs to be heated and the film can be peeled off. A new film is also easy to install because the surface remains clean. Painting with paint has become installing film.

In conjunction with recycling systems for plastics in general, the new film can be used to label plastics in the form of a hot-melt adhesive label. The labels available today are mainly made of paper and in any case with non-thermoplastic adhesives, almost always with adhesives based on coatings. Such paper cannot be processed back into paper without obstacles due to the substances bonded to the paper, be it highly active adhesives or residues left on the adhesive layer. The paper and the adhesives used for it are not thermoplastics and cannot be extruded. They absolutely disrupt the process of recycling plastics and can even lead to total failure. The labels have to be removed or separated from the plastic parts. The label is much simpler in its function and life cycle if it is made from the new film that sticks when heated. Polymers are available that can be melted again at low temperatures with other polymers in extrusion recycling systems and thus cause little or no disruption. The labels made from soft PVC - these stick together due to the glass plate effect, the static and the plasticizer in the PVC - cause problems because PVC cannot be extruded with other polymers. In contrast, the polymer thermoplastic adhesive and the layers connected to it, for example based on polyolefins, are very easy to recycle. The small amounts of the remaining disruptive substances from the label of the new film can be collected in the regeneration extruders using automatic melt filters. The property of the thermoplastic adhesive to stick to most polymers means that, for example, particles of foreign parts floating in the polymer melt bond with the adhesive on its surface and are thus incorporated into other polymers. Practically all polyolefins can be melted with the new polymer labels. If the label consists of polymers that melt at a higher temperature, these must be filtered out using automatic melt filter systems in order to achieve a polymer that can later be easily extruded. The label with the "green dot" ¹ required for recyclable plastics can be produced easily and safely and stuck onto the finished product when heated. The label itself is fully recyclable. It can consist of layers (1), (2), (3) and (4) or only of layers (3) and (4). If it only consists of layers (3) and (4), polymers can be used whose Vicat softening point is in the range of 90 to 104 degrees C, which means that after PVC the largest amount of plastics can be covered.

The setting of the thermoplastic adhesive of layer (4) is very important depending on the application. The choice of surfaces that can be bonded ranges from simple applications, such as plastics from the polyolefin group to each other, to difficult applications, such as bonding metal or glass surfaces. Because the thermoplastic adhesive of layer (4) adheres to metallic surfaces and at the same time the plastic layer (1) can be bonded by overlapping, applications that have so far only been reserved for painting have been achieved by covering it with film and the subsequent possible shrinkage.

For the production of the film, mass production outputs are easily achieved. This reduces costs, especially in comparison to existing systems containing water or solvents. The use of solvents can be eliminated. This is also advantageous for health reasons, since at least aggressive solvents such as ketones and toluenes are considered carcinogenic. The energy required for extrusion to form a non-oriented film is, for example, 0.5 KW to 0.7 KW per kilo of material for polyethylene, depending on the density of the polyethylene. The biaxial orientation process requires up to 2.0 KW per kg of mass, depending on the polymer and the size of the system, which must be converted to the low thickness of the layer (1). This low energy consumption relative to the area weight has led to the erosion of energy-guzzling materials such as wax paper, aluminum foil and film made of regenerated cellulose in the packaging sector. The energy consumption for the evaporation of liquid substances in the very long heat or drying channels in the usual coating systems is eliminated. For the evaporation of the liquid substances in the coating systems, only temperatures below the thermal fixation point of the layer (1) can be used, so that in many cases very capital-intensive and spatially large systems are required for appropriate performance. The materials to be coated are often made from thermoplastics and can be extruded with or without a polymer carrier. If these materials are applied via a roller system as a pasty or liquid mass, solvents must be added in order to achieve distribution of the material via the roller system. The added solvents must later be removed again at great expense.

The extremely rapid reaction of thermoplastics to heat and pressure means that the material is formed in accordance with the behavior of the thermoplastics, and this is achieved with much lower investment costs, process costs and substances that are harmful to the environment. Bonding the layers with the polyurethane adhesive (2) can be carried out at room temperature and in the usual solvent-free conditions for the film's application. The extrusion itself can be carried out at speeds of at least 2 x 10 m = 20 m/min, up to 2 x 100 m = 200 m/min, or with a T-shaped nozzle, known as a slot die, to form a flat sheet at up to 300 m/min, which can be laminated.

at speeds of up to 300 m/min. The film is manufactured in a width of 800 mm - 2,500 mm, and experience has shown that it is manufactured in a width of 800 mm - 1,600 mm. It is advisable to select the output of a production plant depending on the quantities of polymers to be extruded.

The advantage of the process is the functionally better product, the significant savings in energy and capital and the elimination of solvents. The energy consumption just for drying, for example, an adhesive layer on a coating system that works with solvents is up to 1.2 million kcal/h, while only 60,000 kcal/h are required for solvent-free bonding by laminating with the same effect. If water-soluble dispersions are used, the energy required for their slower evaporation reaction is even higher and thus practically impossible. In addition, the "vehicles" in the form of evaporation channels, also known as heat channels or drying channels, are no longer needed. It is also possible to eliminate solvents later when applying the bond to another surface. The carrier of the thermoplastic can do without aggressive binding agents because the pigments adhere to the carrier of the thermoplastic.

A film consisting only of layers (3) and (4) would only fulfill a fraction of the properties that are possible with the film of layers (1), (X2), (2), (3), (4) and (5). Above all, this film lacks the outstanding properties that layers (1), (X2) and (5) make possible. In practice, the film of layers (X2), (3) and (4) would only be an imperfect product, the applications of which are very limited and which, due to the lack of properties, can only be used to a limited extent for the intended purpose. Such applications are possible if optical effects and the high values of deformation due to shrinkage etc. are dispensed with in favor of a cheaper price. It follows that the base film consisting of layers (X2), (3), (4), preferably of layers (3) and (4) and optionally (5), has a limited market in terms of the number of applications, but a large market in terms of quantity.

An opaque colored film for external use, e.g. for protecting sheet metal, achieves useful effects thanks to the properties of the polymers. In this case, layer (3) should preferably be made from an age-resistant polyamide, CO-polyamide or a polyester and a polymer thermoplastic adhesive should be used for layer (4) whose Vicat softening point according to ASTM-D 1525 is lower than that of layer (3), preferably by a value of 40 degrees C. Bonding to the surfaces of, e.g. metal is possible while layer (3) does not yet shrink. Thermal deformation, e.g. pressing with heated tools, leads to an orientation of layer (3), whereby the properties of this film only lead to a moderate improvement due to the unevenly controlled stretch values lengthwise and crosswise. The extremely good adhesion to, e.g. metallic surfaces remains. The following effects are achieved: Resist-

Ster layer as protection against mechanical damage, good impact resistance, coloring, adhesion and no need for any solvents necessary in connection with paints. In practice, the "paint" is given additional impact protection by the extremely good mechanical properties of the polymers of layer (3). This mechanical protection can be achieved particularly safely and efficiently by a preferably multi-layered layer (3). Other layers, consisting of layers (3) and (4) or (1), (X2), (3) and (4) can then be glued onto the surface created in this way and, depending on the choice of adhesive for layer (4), can be "stripped off" or re-glued again and again when heated. The extent to which a layer (5) is required depends on the type of application and the recipe of the thermoplastic adhesive. The fact that polymeric thermoplastic adhesives can be used safely for long-term applications has been confirmed by practice. And everything works without a drying vehicle, enormous energy consumption and without solvents.

Disposing of this coating made from plastic is easier than that of paint. The layer that is glued on using heat is heated again, peeled off and collected. The recycling process developed by Fischer and Menges, "rotary kiln with 100% 02+CH production", allows methanol and other materials to be disposed of in closed chemical plants without emissions. Plastic was first made from gas and, compared to other materials and processes, it was processed with much less energy and less emissions and then converted back into gas after use. The life cycle has been completed.

All in all, a good and economical solution for bonding films to surfaces as decoration and protection.

Heat-bonding film

Short description:

The invention relates to a thermoplastic, multilayered, adhesive film that is transparent or opaque and colored by an extremely large proportion of pigments, the outstanding properties of which are its adhesive strength when heated to a variety of materials, and which is therefore equipped with an outer layer of a polymeric thermoplastic adhesive. This film, which has at least two layers, is laminated to an oriented thermoplastic film using a polyurethane adhesive, so that the individual layers are permanently bonded together. The thermoplastic adhesive layer of the film, which is made from polymers, triggers the bonding when heated. A variety of surface materials can be permanently bonded, decorated and protected. If the temperature is raised above the thermal fixing point of the outer oriented layer, the film can change its dimensions by shrinking or expanding the surface of the film. The film adapts to almost all shapes, whether hemisphere or round arch. The extremely pigmented, protected layer optionally enclosed in the center of the film creates a paint-like effect with maximum opacity. A release layer that can be removed from the thermoplastic adhesive layer helps to improve the processing of the film. Using the film is easy. This development is dedicated to my son Michael.

Claims (31)

Protection claims: 1. Multilayer thermoplastic film, consisting of at least one oriented film, referred to as layer (1), made of a thermoplastic polymer, such as polyester, polyamide, polypropylene or a CO polymer or another orientable thermoplastic, this film referred to as layer (1) connected by a laminating adhesive referred to as layer (2), which is connected to another extruded multilayer, preferably at least two-layer film referred to as layers (3) and (4) to form a multilayer film. The layer (3) consists of a transparent or optionally opaque colored polymer, preferably a polyolefin with at least one layer, the softening point of which is preferably 15 degrees C or more below the temperature point at which the film referred to as layer (1) loses its dimensional stability when heated and whose pigment content is at least 10%, maximum 90% and a second layer, referred to as layer (4), consisting of a polymeric thermoplastic adhesive which, when in contact with other surfaces, forms an adhesive bond to a variety of other surfaces, including metals and glass, when exposed to heat. Preferably, depending on the choice of adhesive, a separating layer (5) covers the layer (4) of the polymeric thermoplastic adhesive. 2. Multilayer film according to claim 1, characterized in that the layer (1) of the oriented film is monoaxially stretched, 3. Multilayer film according to claim 1, characterized in that the layer (1) of the oriented film is bi-axially stretched. 4. Multilayer film according to claims 1-3, characterized in that the layer (1) of the oriented film is thermally fixed. 5. Multilayer film according to claims 1-4, characterized in that the layer (3) is that of an extrudable polymer and this layer (3) is single-layered or multi-layered in structure from the same groups of polymers or with polymers from other generic groups and the softening point of which is optionally 15 degrees C below the temperature point at which the layer (1) loses its dimensional stability when exposed to heat. 6. Multilayer film according to claims 1-5, characterized in that the layer (3) is that of an ionomer, which is composed of ethylene-methacrylic acid copolymers. 7. Multilayer film according to claims 1-5, characterized in that the layer (3) is that of a polyethylene (PE) or optionally that of a CO-polyethylene (CO-PE) or a vinyl acetate polyethylene (EVA-PE) with weight proportions of 0.1% to 30%. 8. Multilayer film according to claims 1-5, characterized in that the layer (3) is that of a polyamide (PA) or a polyester (polyethylene terephthalate PET, polyethylene terephthalate gel PETG). 9. Multilayer film according to claims 1-5, characterized in that the layer (3) is that of a polypropylene (PP) or a CO-polypropylene (ethylene-propylene-CO-polymer CO-PP). 10. Multilayer film according to claim 1, characterized in that the layer (2) of the laminating adhesive is based on polyurethane. 11. Multilayer film according to claims 1-10, characterized in that the second layer of the extruded film, referred to as layer (4), is that of a thermoplastic adhesive based on co- or terpolymers, which is built up with polymeric groups of optionally polyamide, preferably of propylene or ethylene or ethylene-vinyl acetate (EVA), optionally an ionomer, anhydride, maleic anhydride, methacrylic acid, acrylonitrile, synthetic waxes, synthetic rubber, acids and other functional polymeric groups. 12. Multilayer film according to claims 1-11, characterized in that the thermoplastic adhesive of the layer (4) of the extruded film is based on ethylene (polyethylene PE) and becomes sticky according to Vicat in a thermal range of 49 degrees C to 89 degrees C, 13. Multilayer film according to claims 1-11, characterized in that the thermoplastic adhesive of the layer (4) is based on medium or high density polyethylene or optionally polypropylene or CO-polypropylene and becomes sticky according to Vicat in a thermal range of 90 degrees C to 165 degrees C. 14. Multilayer film according to claims 1-11, characterized in that the thermoplastic adhesive of the layer (4) is based on polyamides or polyesters (PET and PETG) and becomes sticky according to Vicat in a thermal range below 260 degrees C. 15. Multilayer film according to claims 1-11, characterized in that spacers, known as antiblocking agents, and lubricants, known as slip agents, are added to the polyolefin-based thermoplastic adhesive of the layer (4), and the value of each of these can be from 50 ppm to 8000 ppm. 16. Multilayer film according to claims 1-11, characterized in that the inner film, consisting of the layers (3) and (4), is oriented and optionally thermally fixed and the stretch values for the orientation are in the range of 2 times to 56 times the value. 17. Multilayer film according to claims 1-16, characterized in that between the layer (1) and the layer (2) of the laminating adhesive there is a further layer (X1) of a polymer with a softening point that is at least 15 degrees C below the temperature point at which the layer (1) loses its dimensional stability when heated. 18. Multilayer film according to claims 1-17, characterized in that the layer (Xl) can also be a coating based on polyvinyl chloride (PVC), chlorinated polypropylene, polyvinylidene chloride (PVDC), polyacrylonitrile (PAN), acrylic, polymethacrylic resin and other polymers. 19. Multilayer film according to claims 1-16, characterized in that between the layer (2) of the polyurethane adhesive and the layer (3) of the colored layer of the polymer there is a further layer (X2) of a polymer with a softening point and this polymer has a softening point that is at least 15% lower than the temperature point at which the layer (1) loses its dimensional stability when exposed to heat. 20. Multilayer film according to claims 1-16, characterized in that a transparent extrudable polymer is used as layer (3). 21. Multilayer film according to claims 1-16, characterized in that a polymer with a proportion of 10% to 90% titanium dioxide, known as TIO2, is used as layer (3), 22. Multilayer film according to claims 1-16, characterized in that a polymer with a proportion of preferably 10% to 90% of a colored organic or inorganic pigment with polymers as a binder is used as layer (3), which can also contain metallic parts. 23. Multilayer film according to claims 1-16, characterized in that the pigmented layer (3) contains a processing aid - known as a dispersant. 24. Multilayer film according to claims 1-22, characterized in that the materials for the layers (1), (X1), (X2), (3) and (4) contain additives, optionally UV light stabilizers, thermal stabilizers and flame retardant additives are incorporated. 25. Multilayer film according to claims 1-24, characterized in that the thermoplastic adhesive of the layer (4) is covered by a separating layer (5), the thickness of which can preferably range from 5 my to 50 my. 26. Multilayer film according to claims 1-25, characterized in that a thermoplastic material with the layers (X2), optionally (3) and (4) is extruded as layer (5), which becomes adhesive to the layers (3) and (4) but not sticky. 27. Multilayer film according to claims 1-25, characterized in that the layer (5) is applied as a finished film immediately after the extrusion of the layers (X2), (3) and (4) and before winding up the film consisting of the layers (X2), (3), and (4) as layer (5) and all layers have a temperature of less than 49 degrees C. 28. Multilayer film according to claims 1-25, characterized in that the film consists without the separating layer (5) and the thermal reaction of the adhesive of the layer (4) does not occur in a range below 49 degrees C. 29. Multilayer film according to claim 26, characterized in that the layer (5) is equipped with an internal release agent incorporated into the polymer of the layer (5), which migrates to the outer surface of the layer (5) after extrusion, and the layer (5) achieves only a low adhesive bond to the layer (4). 30. Multilayer film according to claim 25, characterized in that the layer (5) is provided with an external release agent to prevent the adhesion of other polymers and this release agent is applied to the layer (5) and the layer (5) achieves only a low adhesive bond to the layer (4). 31. Multilayer film according to claims 5-9, 11-16 and 19 - 30, characterized in that the film is produced without the layers (1), (X1) and (2) and consists only of the layers (3), (4), optionally (5) or only of the layers (X2), (3), (4) and optionally (5).