WO1999030902A1

WO1999030902A1 - Thin-walled, electromagnetic shielding, deep-drawn shaped part, method for the production thereof, and an intermediate product which can be utilized during said method

Info

Publication number: WO1999030902A1
Application number: PCT/EP1998/008183
Authority: WO
Inventors: Curt Niebling
Original assignee: Curt Niebling
Priority date: 1997-12-16
Filing date: 1998-12-14
Publication date: 1999-06-24
Also published as: DE19755952C1; AU2272799A

Abstract

The invention relates to a thin-walled, electromagnetic shielding, deep-drawn shaped part having a layer comprised of a film material which can be cold-stretched. A mesh, net or woven material is laminated on said shaped part with the assistance of a heat-seal bonding agent containing a small-sized electrically conductive pigment. Said mesh, net or woven material has a mesh width smaller than 1 mm and is made of a metal wire having a wire strength less than 100 νm, said metal wire being comprised of a soft material which can be drawn. By virtue of the low electric contact resistance and high shielding attenuation of said material, such shaped parts can, for example, be used as a shielding housing in the area of mobile radio telephones. For production, an initially flat composite material comprised of a film which can be cold stretched, a heat-seal bonding agent layer and a metal structure can be immediately and directly pressurized with a hydraulic fluid, preferably compressed air, at a working temperature lower than the softening temperature of the film material, and can be formed on the mold hollow cavity of a negative mold or positive mold in an impact-like manner with a hydraulic fluid pressure greater than 20 bar.

Description

Thin-walled, electro-magnetic shielding, deep-drawn

Molded part,

Process for its preparation, and an intermediate product which can be used in this process

Description:

The present invention relates to a thin-walled, electromagnetically shielding, deep-drawn molded part and a method for its production. The invention further relates to an intermediate product which can be used in this process. Because of their electromagnetic magnetic shielding, the molded parts according to the invention can be used in particular for housing electrical and / or electronic devices which generate electromagnetic interference radiation. The molded parts according to the invention can preferably be used as screen housings or screen housing parts of mobile telephones, computers, laptops, shavers and the like, and for covering printed circuit boards.

Methods for high pressure deformation with the measures from the preamble of claim 10 are from the German Offen- document 38 44 584 known. This publication does not address the incorporation of metal-containing structures into the thin-walled, deep-drawn molded plastic parts described there.

Furthermore, German Offenlegungsschrift 36 01 153 discloses a deep-drawn molded part and a method for its production. In this case, at least on a first layer made of a deep-drawable material, a second layer made of a non-deep-drawable material is applied, and subsequently both layers are deformed together using deep-drawing. The non-thermoformable material can be braids, fabrics or nonwovens made of metal. If this second layer consists of certain metals, the shielding properties of metals against electromagnetic radiation can be exploited, as a result of which molded plastic parts can be produced with a favorable shielding effect. Before the deep-drawing process, the second layer can be temporarily adhered to the first layer, for example with the aid of an adhesive. This document contains no information on the type and selection of this adhesive.

Typically, adhesives that are supposed to bond another material with thermoplastic materials are electrically non-conductive, organic materials. The adhesive creates a well-adhering, electrically non-conductive insulating layer on the metal structure. The presence of this insulating layer causes difficulties if the metal structure of the molded part, which acts as a Faradey * cage, is later to be connected to device components in an electrically conductive manner. The deep-drawing process described in DE-OS 36 01 153 is not comparable to the high-pressure deep-drawing process of DE-OS 38 44 584.

REPLACEMENT BLAπ (RULE 26) The object of the present invention is to provide easy-to-manufacture, thin-walled, deep-drawn molded plastic parts which are provided with an integrated shield against electromagnetic radiation and which have an electrical contact resistance of less than 200 milliOhm. These molded parts should preferably be usable as screen housings in the mobile radio sector.

Furthermore, the method of DE-OS 38 44 584, which goes back to the same applicant, is to be modified and improved so that thin-walled, electromagnetically shielding, deep-drawn molded parts of the type mentioned above can be obtained by this method.

One embodiment of the solution to this problem according to the invention is a thin-walled, electrically shielding, deep-drawn molded part with a layer of a cold-stretchable film material to which a fine-particle, electrically conductive pigment-containing heat seal adhesive, a grid, mesh or fabric is laminated , which has a mesh size of less than 1 mm and which is formed from a metal wire having a wire thickness of less than 100 μm from a soft / drawable metal.

Advantageous refinements and developments result from the subclaims for this molded part.

Another embodiment of the solution of the above object relates to a method for producing a thin-walled, deep-drawn molded part provided with an integrated electro-magnetic shield.

Starting from a process whereby a flat multilayer composite material, which has at least one layer of a cold-stretchable film material, is directly and directly pressurized with a pressure fluid at a working temperature below the softening temperature and is suddenly molded onto the mold cavity of a negative mold or positive mold at a pressure fluid pressure greater than 20 bar Solution to the above problem, characterized in that a lattice, mesh or fabric is laminated to the flat cold-stretchable film material with the aid of heat seal adhesive, which contains a finely divided, electrically conductive pigment, which has a mesh size of less than 1 mm and which consists of one, one Wire thickness less than 100 µm metal wire is formed from a soft, pullable metal; and the composite material thus obtained is deformed.

Advantageous refinements and developments result from the subordinate claims to this method.

The composite material used in the above-mentioned process can be produced by applying the specific, flowable heat-sealing adhesive containing an electrically conductive pigment to the cold-stretchable film material, applying the specific metal structure to this adhesive layer and the layer material thus obtained under the action of heat and Pressure is laminated. Alternatively, a previously produced and independently manageable preliminary or intermediate product can be provided, which has the metal structure and the specific heat seal adhesive.

In this case, an intermediate product is provided for use in the aforementioned method, which comprises: a protective film made of a plastic that is easily removable from the dry heat seal adhesive; a dry thermoplastic heat seal adhesive layer applied to this protective film, which contains an electrically conductive pigment and which can be heat activated at a temperature of 80 ° C or higher, a grid, mesh or fabric which is adjacent to and / or at least partially embedded in the heat seal adhesive layer and has a mesh size has less than 1 mm and which is formed from a metal wire having a wire thickness of less than 100 μ made of a soft, pullable metal.

Advantageous refinements and developments result from the subclaims for this intermediate product.

The molded parts according to the invention are obtained by simultaneous, joint deformation of a composite material. This - initially flat - composite material has at least three components, namely a layer of cold-stretchable film material serving as a base or support for the molded part; a certain metal structure which - in the sense of a Faraday 'see cage - provides the required shielding against electromagnetic radiation; and a selected adhesive that connects the metal structure to the film material and that increases the shielding attenuation of the molded part due to its electrical conductivity.

The cold-deformable film materials used are preferably polycarbonates (for example the MACROLON grades sold by BAYER AG), ABS polymers (butadiene / acrylonitrile / styrene polymers), polyesters, in particular aromatic polyesters (for example polyalkylene terephthalates), poly amides (for example PA 6 or PA 66 grades, furthermore high-strength aramide films), polyimides (for example the films sold under the trade name "CAPTON") and also the copolymers of tetrafluoroethylene and hexafluoropropylene known under the name FEB. Furthermore, organic thermoplastic cellulose esters, in particular their acetates, propionates and acetobutyrates, can also be used in individual cases. In some cases, the above-mentioned film materials are also commercially available in types or types that have an increased electrical conductivity. For example, the ASA film types marketed by BAYER AG are mentioned here, polycarbonate-based films with increased electrical conductivity. If available, the above-mentioned film types with increased electrical conductivity are preferably used. Film materials made from polycarbonates ("MACROLON", "ASA"), polyalkylene terephthalates, ABS polymers and polyimides ("CAPTON") are particularly preferably used.

These film materials can preferably have layer thicknesses between 50 and 500 μm. Particularly good results are obtained, for example, with polycarbonate films ("MACROLON" or "MACRO-FOL" or "ASA" from BAYER AG) or with ABS films, each with a layer thickness between 100 and 200 μm. A layer thickness of 500 μm already provides a deep-drawn, self-supporting molded part.

An important area of use for molded parts according to the invention is shielded housings in the mobile radio sector. Various compartments can operate in the housing of a mobile phone (cell phone), which operate at different operating frequencies. Each compartment must be carefully shielded from the neighboring compartment to avoid mutual interference. The shielding attenuation, which can be determined according to ASTM D 4935-89, for example, should be at least 30 dB. Typically, such _From screening by enclosure within a metallic Creates a shell that acts as a Faraday cage. The use of full-surface metal foils is problematic due to the limited deep-drawing ability and the sufficient adhesion to the carrier foil. On the other hand, the metallic shell must be largely closed. Electromagnetic interference radiation would pass through or emerge to an intolerable extent even through holes or gaps a few millimeters wide. In the context of the present invention, it was recognized that both the required electromagnetic shielding and the required deep-drawing ability can be achieved if a mesh, mesh or fabric with a mesh size of less than 1 mm is used as the metal structure, and that of a wire gauge smaller than 100 microns metal wire is formed from a soft pullable metal. Examples of such metals are aluminum, copper, nickel, tin and their alloys including brass. Metal mesh made of copper, aluminum or brass is preferably used. For example, standard fabrics with a smooth weave can be used. The mesh size can preferably be 200 to 800 μm. Metal meshes made of very thin metal wires are preferably used, for example with wire thicknesses of 20 to 60 μm, because such metal meshes can be easily deformed under the deep-drawing conditions provided according to the invention and have no restoring force after the deformation. Particularly good results are achieved with a fabric made of copper wire, which has a wire thickness of approximately 50 μm, the fabric having a mesh size of approximately 460 μm. Annealed copper grids of this type are particularly preferred because the preceding annealing further reduces the bending stiffness of the copper wire. Such metal meshes are commercially available, for example from wire weaving mills that produce screen printing meshes.

As an adhesive for permanently _d and deep-drawable connecting ieser _M etallstruktur with the cold-stretchable carrier film a heat seal adhesive is used according to the invention. Organic adhesives are referred to as heat seal adhesives which, when dry, have thermoplastic properties and which melt through the action of heat and are thus heat-activatable. Typical temperatures for heat activation are about 120 to 140 ° C; Special types of heat seal adhesive can also be heat activated at temperatures greater than or equal to 80 ° C, provided that a longer pressing time is also used. These heat seal adhesives are preferably water-dispersible adhesives based on aliphatic polyurethane (s). Typically, the dispersibility of these organic polymers in water is based on the polyol used to produce the polyurethane having ionic groups such as carboxylic acid groups or quaternary ammonium groups is substituted. Aqueous dispersions which contain finely divided, dispersed, thermoplastic polyurethane which is suitable as a heat seal adhesive in the context of the present invention are described, for example, in US Pat. No. 4,147,679 (Scriven et al.). In addition, heat seal adhesives based on aliphatic, thermoplastic polyurethanes are commercially available. Depending on the water content, these water-dispersed thermoplastic polyurethanes are highly viscous masses with a flow behavior reminiscent of honey.

If the processing of the adhesive to produce the composite material and the high-pressure deformation of the composite material are practically carried out in a single operation within a few hours, preferably within a processing time of not more than 5 to 6 hours, a hardener can also be incorporated into the adhesive. For example, an aliphatic polyisocyanate, such as one of the DESMODUR types (trademark of BAYER AG), can be used as the hardener. In this case, an addition of hardener of 0.5 to 2.5% by weight is sufficient and expedient. If, on the other hand, an independently manageable and storable intermediate product consisting of protective film, heat seal adhesive and metal structure is provided, such a hardener additive should be avoided. The system of glue and hardener gradually crosslinks even at room temperature, whereby the thermoplastic properties are lost. A heat seal adhesive without hardener should therefore preferably be provided for such an intermediate product.

According to an essential aspect of the invention, such a heat seal adhesive is used which contains a sufficient amount of electrically conductive pigment so that the finished deep-drawn part according to the invention has an electrical contact resistance of less than 200 milliOhm. Suitable electrically conductive pigments include metal powders such as powdered aluminum, copper, nickel, tin, brass or bronze, or carbon in the form of carbon black or graphite, or electrically conductive metal oxides such as magnetite. Preferred electrically conductive pigments are carbon black or graphite, which can be distributed well in aqueous adhesive dispersions of the type considered here. Furthermore, the tendency to phase separation and settling or suspension is low. The water-dispersible heat seal adhesive should preferably contain carbon black or graphite as the electrically conductive pigment and may additionally contain one of the metal powders or powdery metal oxides mentioned. Additional metal powders can be treated with a surfactant-based anti-settling agent.

The dispersibility and the separation behavior of the pigments in / from the aqueous adhesive dispersion is also influenced by the particle size of the pigments. In the case of carbon black as the conductive pigment, types with an average primary particle size of 50 nm or less are preferably used. Additionally introduced metal powders can have a grain size smaller than 5 µm, preferably a grain size smaller than 2 µm. point. Such pigments can easily be uniformly distributed in the aqueous adhesive dispersion by stirring.

Such an amount of electrically conductive pigment is distributed in the adhesive so that an electrically conductive adhesive layer is finally obtained which, when dry, has an electrical contact resistance of less than 200 milliOhm. Typically, about 10 to 40% by weight, based on the solids weight of adhesive and pigment, is incorporated into the adhesive. For example, good results are obtained when about 20% by weight of carbon black or graphite is incorporated into the adhesive. The electrical conductivity of an adhesive layer produced in this way increases the shielding attenuation of deep-drawn parts according to the invention.

Examples of starting materials for such electrically conductive heat-sealing adhesives are those from Farbenfabrik Pröll GmbH & Co. , 91781 Weißenburg, Germany are used under the trademark AQUAPRESS adhesive systems (essentially aqueous dispersions of aliphatic polyurethanes) that have not yet been mixed with electrically conductive pigment. To produce electrically conductive heat seal adhesives which can be used according to the invention, electrically known pigment, in particular carbon black and, if appropriate, additionally a finely divided metal powder can be incorporated into these known AQUAPRESS adhesives.

To produce the thin-walled, deep-drawn molded part provided with an integrated electro-magnetic shielding, a preliminary or intermediate product can be provided, which consists of a protective film, the metal structure and the dried, but still heat-activated heat seal adhesive layer. The protective film is intended to facilitate production and handling and is used in particular to prevent the composite material from passing through a heated roller pair to prevent adhesive from sticking to one of these rollers. The protective film should be easy to remove from the dried adhesive. A largely inert protective film made of polyethylene, polypropylene, polyester or polyfluorocarbon is preferably provided. A layer thickness of the protective film of less than 50 μm is typically completely sufficient; For example, a protective film made of the polymers mentioned can be used with a layer thickness of 20 to 40 μm.

The heat-seal adhesive filled with electrically conductive pigment is applied to the entire surface of the flat protective film. The adhesive layer can be applied, for example, using the screen printing method. Experiments have shown that the ultimate adhesive strength also depends on the layer thickness of the adhesive. Within certain limits, a higher layer thickness increases the adhesive strength that can be achieved. The layer thickness of the adhesive layer should be about 5 to 50 μm; a layer thickness of approximately 15 to 30 μm is preferably provided. In order to achieve such layer thicknesses, it is advisable to apply the screen several times. Alternatively, other methods of applying the flowable, highly viscous adhesive can also be provided, such as spreading with the aid of a doctor blade, or lamination with the aid of rollers. The metal structure is placed on the adhesive layer, pressed into the liquid or plastic adhesive mass and fixed in places. This composite is then dried, for example with hot air in a continuous oven.

According to an alternative method of working, the liquid adhesive with the electrically conductive pigment is applied over the entire surface of the protective film. This composite is dried, for example with hot air in a continuous oven. The metal structure is then placed on the dried adhesive layer. Another protective film is placed on the metal structure. This association is through a heated pair of rollers and connected or laminated together. One of the two protective films is removed before further processing.

The intermediate product thus obtained is stored until further processing. The adhesive, which is preferably not mixed with hardener and therefore not crosslinked, remains thermoplastic and heat-activatable and can be joined in a later step by the action of heat to the cold-stretchable film material provided according to the invention. In this respect, this preliminary or intermediate product is an independently manageable and storable product on the way to the production of a molded part according to the invention.

For further processing, the flat, cold-stretchable film material provided for the molded part is provided, for example an ABS film or a polycarbonate film, in particular an electrically conductive ASA film with a layer thickness of approximately 200 μm. The intermediate product is placed on this film so that the protective film is removed from the cold-stretchable film. The composite material thus obtained is heated to activate the adhesive. For this purpose, heating takes place to a temperature above the activation temperature of the heat seal adhesive and below the softening temperature of the cold-stretchable film material. Typically, it is heated to a temperature in the range from 80 to 140 ° C. Heating to rather low temperatures in the range of approximately 80 to 100 ° C. is preferably provided, with simultaneous longer pressure exposure of 50 seconds or / longer. The combined action of heat and pressure leads to an intimate and permanent connection of the metal structure with the cold-stretchable film. In this way, the composite material can be produced in the form of endless webs, from which certain outlines are later punched out, which are fed to the high-pressure molding for producing molded parts according to the invention. According to an alternative method of operation, the already cut intermediate product can be partially placed on an endless web of the cold-stretchable film in the sections where deep-drawing is to be carried out. This section of cold-stretchable film provided with a metal structure and adhesive layer is passed through a pressing apparatus in order to permanently connect the metal structure to the cold-stretchable film under the action of heat and pressure. This endless sheet material is then fed to the deep-drawing process in sections.

According to a further alternative, the cold-stretchable film material and the intermediate product can each be provided in the desired outline, which are fed to the immediately subsequent high-pressure deformation after the lamination, while still warm. In this case, reheating of the composite material to the working temperature of the high-pressure deformation step is avoided.

On the other hand, the use of a prefabricated intermediate containing the metal structure and the adhesive is by no means mandatory.

Alternatively, molded parts according to the invention can be produced in a plurality of immediately successive work steps. First, heat seal adhesive is applied or provided, which is provided with the electrically conductive pigment. This adhesive is applied evenly to individual die-cut pieces of the cold-stretchable film, which are provided with alignment marks. The metal structure punched out in the same outline is placed on the adhesive layer. This layer structure is laminated in a compression apparatus under the action of heat and pressure. For the rather low temperatures between about 80 and 100 ° C, a pressing time between about 100 WO 99/30902 -1 -4.- PCT / EP98 / 08183

and 300 seconds under a pressure of about 100 to 300

2 N / cm can be provided. The laminated composite material, which is still warm, is then immediately subjected to high-pressure deformation.

In principle, the flat multilayer composite material can be deformed to form the molded part according to the invention by known deep-drawing processes. However, an isstatic high-pressure deformation is preferably provided, in which a pressure fluid of more than 20 bar acts directly and directly on the flat multilayer composite material and abruptly forms it on the mold cavity of a negative mold or positive mold. Such an isostatic high-pressure deformation process is described in detail in German Offenlegungsschrift 38 44 584 and the associated patent document 38 40 542. A device for carrying out this isostatic high-pressure deformation process is described in detail in German Patent 41 13 568. By expressly referring to these publications, the content thereof - insofar as it is helpful and necessary for understanding and implementing the present invention - should also be made part of the present documents.

The moldings obtained after this isostatic high-pressure deformation are thin-walled; their wall thickness is usually only a few 100 micrometers. Typically, the molded parts had an essentially uniform layer thickness of less than 1.2 mm in all surface sections. If necessary, these moldings can be back-injected with additional synthetic resin.

The following example serves to further explain the invention without restricting it. Example:

The following are provided as starting materials:

Polycarbonate film (ASA from BAYER AG) with a layer thickness of 200 µm in the form of an endless web rolled up into a roll.

Metal structure, namely a metal mesh made of copper wire with a smooth weave and a mesh size of 458 μm; the copper wire has a wire thickness of 50 µm. Such a copper wire mesh can be obtained, for example, from Spoerl GmbH, D-72517 Sigmaringendorf.

Heat seal adhesive, in the form of an aqueous dispersion of various aliphatic polyurethanes, which has already been mixed with about 20% by weight of carbon black and has been prepared for use by the manufacturer. (Such an adhesive was provided on a trial basis by Farbenfabrik Pröll GmbH & Co., D-91781 Weißenburg and is based on the AQUAPRESS HT grade (registered trademark of Farbenfabrik Pröll GmbH & Co.)).

Individual pieces measuring 8 x 8 cm are punched out of the sheet-like polycarbonate film. Each piece of film is provided with markings for positioning. An approx. 30 μm thick layer of soot filled with carbon black is applied to each piece of film using the screen printing process; this is done by three screen printing jobs.

A cut-out piece of copper wire fabric with the same dimensions is placed on the wet adhesive layer.

The layer material produced in this way is transferred by hand to a pressing apparatus and there at a temperature

REPLACEMENT SHEET (HEGEL26) of about 100 ° C and under a pressure of about 180 N / cm ^{2 for} 60 seconds and laminated.

The still warm composite material is placed by hand on the wide frame of a negative mold, the mold cavity of which depicts a square board housing with a side length of approximately 40 mm and a depth of approximately 8 mm. The copper wire mesh lies on the form edge. The press is closed until the edge of the counterpart lies close to the top of the film. The mold is closed under a hydraulic medium pressure of approximately 100 t. Heated compressed air, which has a temperature of approximately 120 ° C., is blown in through the counterpart. The compressed air supply is controlled by an inlet valve that remains open for about 1 lake. The inlet valve is then closed and an outlet valve is opened in order to relieve the pressure on the entire interior of the mold. The mold is then opened and the deep-drawn sheet is removed.

The copper wire mesh has undergone this sudden high-pressure deformation without cracking and / or other recognizable, significant change in the fabric texture. The layer thickness of the board housing is uniform in every cross-section. The edge of the board housing is cut to a width of about 10 mm. The circuit board housing is then attached to a printed circuit board in the usual way. The electrical contact resistance is measured using conventional methods and is approximately 160 milliOhm. The quadratic surface resistance is measured on the board housing using the so-called four-point measuring method. Based on the measured value, a shielding attenuation of about 72 dB is expected. Such shield housings are suitable for use in the mobile radio sector.

Claims

Claims:

1. Thin-walled, electro-magnetically shielding, deep-drawn molded part, with a layer of a cold-stretchable film material, to which a grid, mesh or fabric is laminated with the aid of heat-seal adhesive containing a finely divided, electrically conductive pigment that has a mesh size of less than 1 mm and which is formed from a metal wire having a wire thickness of less than 100 μm from a soft, pullable metal.

2. Fαrmteil according to claim 1, characterized in that the cold-stretchable film material is a polycarbonate film or an ABS film, each with a layer thickness of 50 to 500 microns.

3. Molding according to claim 1 or 2, characterized in that the heat seal adhesive is a water-dispersible adhesive based on aliphatic polyurethane (s) which can be heat-activated at a temperature of 80 ° C or higher,

4. Molding according to one of claims 1 to 3, characterized in that the heat seal adhesive contains 10 to 40% by weight (based on the solid weight of adhesive and pigment) of finely divided electrically conductive pigment.

5. Molding according to one of claims 1 to 4, characterized in that the electrically conductive pigment is a metal powder, such as aluminum, copper, nickel, tin, brass or bronze powder or carbon black, graphite or magnetite. WO 99/30902 _ ^ _ PCT / EP98 / 08183

6. Molding according to one of claims 1 to 5, characterized in that the electrically conductive pigment is carbon black or graphite.

7. Molding according to one of claims 1 to 4, characterized in that the heat seal adhesive contains carbon black or graphite as an electrically conductive pigment and a metal powder which is selected from aluminum, copper, nickel, tin, brass or bronze powder.

8. Molding according to one of claims 1 to 7, characterized in that the metal grid, mesh or mesh has a mesh size of 200 to 800 microns.

9. Molding according to one of claims 1 to 7, characterized in that the metal grid, mesh or fabric consists of a metal wire which has a wire thickness of 20 to 60 microns.

10. A method for producing a thin-walled, deep-drawn molded part provided with an electromagnetic shield, wherein a flat multilayer composite material which has at least one layer of a cold-stretchable film material, directly and directly with a at a working temperature below the softening temperature of this film material Pressurized fluid and at a pressure fluid pressure greater than 20 bar is suddenly molded onto the mold cavity of a negative mold or positive mold, characterized in that on the flat, cold-stretchable film material with the help of heat seal adhesive, which is a finely divided, electrical contains conductive pigment, a lattice, mesh or fabric is laminated on, which has a mesh size of less than 1 mm and which is formed from a metal wire with a wire thickness of less than 100 μm from a soft, drawable metal; and the composite material thus obtained is deformed.

11. The method according to claim 10, characterized in that the deformation of the composite material is carried out at a working temperature between 80 and 140 ° C.

12. The method according to any one of claims 10 to 11, characterized in that the shaping of the composite material is carried out within a period of less than 2 seconds.

13. The method according to any one of claims 10 to 12, characterized in that a cold-stretchable film material is formed with a layer thickness between 50 and 500 microns.

14. The method according to any one of claims 10 to 13, characterized in that a cold-stretchable film material made of thermoplastic materials on the basis of polycarbonates, ABS polymers, polyamides, polyimides, polyesters, organic cellulose esters or Polyfluorkαhlenwasser- is formed.

15. The method according to any one of claims 10 to 14, characterized in that a water-dispersible adhesive based on aliphatic polyurethane (s) is used as the heat seal adhesive, which can be heat-activated at a temperature greater than / equal to 80 ° C.

16. The method according to any one of claims 10 to 15, characterized in that a heat seal adhesive is used which up to an amount of 10 to 40 wt .-% (based on the solid weight of adhesive and pigment) with a finely divided, electrically conductive pigment is filled.

17. The method according to any one of claims 10 to 16, characterized in that a metal powder such as aluminum, copper, nickel, tin, brass or bronze powder or carbon black, graphite or magnetite is used as the electrically conductive pigment.

18. The method according to any one of claims 10 to 17, characterized in that carbon black or graphite is used as the electrically conductive pigment.

19. The method according to any one of claims 10 to 18, characterized in that a grid, mesh or fabric made of a soft, pullable metal, namely aluminum, copper, nickel, tin or their alloys such as brass is used.

20. The method according to any one of claims 10 to 19, characterized in that a metal grid, mesh or mesh with a mesh size of 200 to 800 microns is used.

21. The method according to any one of claims 10 to 20, characterized in that the flowable heat seal adhesive provided with finely divided, electrically conductive pigment is applied over the entire surface of the flat, cold-stretchable film material, the metal structure is placed on the adhesive layer; and the layer material thus obtained is laminated under the action of heat and pressure.

22. The method according to any one of claims 10 to 21, characterized in that to produce an intermediate product on a protective film which is easily removable from the heat seal adhesive, the flowable heat seal adhesive provided with finely divided, electrically conductive pigment is applied over the entire surface; and the metal structure is placed on this adhesive layer and at least partially pressed into the adhesive layer; and so ^"obtained layered material is dried under heat.

23. The method according to claim 22, characterized in that a protective film made of polyethylene, polypropylene, polyester or polyfluorocarbons is used.

24. The method according to claim 23, characterized in that the intermediate product thus obtained is assembled and placed on a cold-stretchable film material; and the double layer thus obtained under the influence of

Heat and pressure is laminated to produce a composite material that is subjected to high pressure deformation.

25. The method according to claim 24, characterized in that is heated to a temperature of 80 to 140 ° C for lamination.

26. The method according to claim 24 or 25, characterized in that for lamination, a pressure action takes place under a pressure of 100 to 300 N / cm ² .

27. The method according to any one of claims 24 to 26, characterized in that the lamination is subjected to pressure over a period of 10 to 300 seconds.

28. The method according to any one of claims 10 to 27, characterized in that the composite material is arranged between a negative mold or a positive mold and a counterpart in a defined position to carry out the high pressure deformation,

Form and counterpart are closed pressure-tight; and a pressure fluid is fed through one or more channels recessed in the counterpart, which acts directly and directly on the composite material to be deformed and forms this composite material isostatically on a structure or recess formed in the mold, the mold, counterpart and pressure fluid having at least the working temperature.

29. The method according to claim 28, characterized in that compressed air is used as the pressure fluid.

30 intermediate product, for use in a method according to any one of claims 22 to 29, characterized by a protective film made of a plastic easily removable from the dry heat seal adhesive; an on this protective film over the entire surface applied troc _k enes thermoplastic Heißsiegelkleber- layer which contains an electrically conductive pigment and which can be heat-activated at a temperature of 80 ° C or higher;

- A grid, mesh or fabric at least partially embedded in this heat seal adhesive layer, which has a mesh size of less than 1 mm and which is formed from a metal wire having a wire thickness of less than 100 μm from a soft, pullable metal.

31. Intermediate product according to claim 30, characterized in that the heat seal adhesive is a water-dispersible adhesive based on aliphatic polyurethane (s).

32. Intermediate product according to claim 31, characterized in that the heat seal adhesive contains 10 to 40% by weight (based on the solids weight of the adhesive and pigment) of finely divided, electrically conductive pigment.

33. Intermediate product according to one of claims 30 to 31, characterized in that the electrically conductive pigment is a metal powder such as aluminum, copper, nickel, tin, brass or bronze powder or carbon black, graphite or magnetite.

34. Intermediate product according to one of claims 30 to 32, characterized in that the electrically conductive pigment is carbon black or graphite.

35. Intermediate product according to claim 32, characterized in that the electrically conductive pigment is carbon black or graphite and additionally contains a metal powder which is selected from aluminum, copper, nickel, tin, brass or bronze powder.

36. Intermediate product according to one of claims 30 to 35, characterized in that the metal grid, mesh or fabric consists of a fine metal wire made of aluminum, copper, nickel, tin or their alloys including brass.

37. Intermediate product according to one of claims 30 to 36, characterized in that the metal grid, mesh or mesh has a mesh size of 200 to 800 microns.

38. Intermediate product according to one of claims 30 to 37, characterized in that is delimited on both sides by a protective film.