Classifications

• • H—ELECTRICITY
  • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
  • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
  • H05K9/00—Screening of apparatus or components against electric or magnetic fields
  • H05K9/0073—Shielding materials
  • H05K9/0081—Electromagnetic shielding materials, e.g. EMI, RFI shielding
  • H05K9/009—Electromagnetic shielding materials, e.g. EMI, RFI shielding comprising electro-conductive fibres, e.g. metal fibres, carbon fibres, metallised textile fibres, electro-conductive mesh, woven, non-woven mat, fleece, cross-linked

Definitions

• the invention relates to a shield against electromagnetic interference sources made of a fleece made of synthetic fibers, yarns or the like, e.g. made of a polyamide or polyester, and a metal pad, or the like, each fiber, each yarn. of the fleece encased all around.
• Electromagnetic interference sources which can be high-frequency transmitters from radio stations, taxi companies or the police, for example, can affect the operation of electronic systems. Any errors that occur here can hardly be calculated.
• the shields mentioned at the outset were developed from a nonwoven and a metal layer, which require less effort and, in particular, are easier to handle than shields made of sheet steel or galvanized iron sheet known up to that point.
• the invention has for its object to provide a shield against electromagnetic interference sources of the type described above from a fleece and a metal pad, the handling of which is considerably simplified and which nevertheless enables reliable shielding of electronic systems against electromagnetic interference sources.
• This object is achieved in that the fleece has a weight of 10 to 40 and that with a metal coating has a weight of 25 to 70 g / m 2 . It has been found that a combination of the shield made of a fleece with the appropriate basis weight and a metal coating with the stated basis weight results in excellent electronic shielding effects, while the handling of the shield or the material forming the shield remains guaranteed.
• the shield comprising the fleece and the metal coating or the material forming this shield can be processed in a wallpaper-like manner, which leads to a considerable reduction in the installation complexity of the shield.
• the shielding is given a continuous, full-surface metal layer.
• the metallized fleece can flexibly adapt to any room shape. It can easily be cut using scissors, which guarantees wallpaper-like processing.
• the shielding according to the invention if it is used on walls, ceilings and floors, can be provided with commercially available carpets or wallpapers. Due to the comparatively low weight of the material forming the shield, support structures are unnecessary.
• Polyamide 6 Perlon
• polyamide 6/6 nylon
• the thickness of the fibers, yarns or the like forming the fleece. should expediently between 1 and 30, preferably between 2 and 20 dtex, which ensures sufficient strength with sufficient elastic properties.
• the nonwoven is produced as a spunbonded fabric from intermingled endless filaments, the nonwoven has no closed fiber layers, which means that it has considerably more favorable properties with regard to its tear strength.
• the metal layer which preferably consists of copper and / or silver, of copper and nickel or of copper and tin, encloses each individual fiber of the spunbonded nonwoven separately, no closed surfaces are created, the breathability of the material forming the shield with a high metal content being used for the shielding effect is advantageous, is retained. In addition, due to the complete covering of the fibers, yarns or the like forming the nonwoven. no difference between the front and back effect of the shield.
• the metal layer which is preferably designed as a copper or metal layer, is soft and ductile, so that the mechanical properties of the fleece, namely its elasticity, its permeability and its ability to be cut, are fully retained.
• the metal coating is expediently coated with a corrosion-preventing material, which can be an acrylate-based surface coating.
• a corrosion-preventing material which can be an acrylate-based surface coating.
• the surface coating is designed as a two-component acrylate copolymer.
• the metal pad is protected in particular against galvanic corrosion.
• a shield against electromagnetic interference sources in such a way that it also shields interference in the low-frequency range below 1 MHz and accordingly prevents the magnetic field component of an electromagnetic field, which predominates in this frequency range, from having adverse effects.
• the metal coating has particles made of a ferromagnetic material.
• Such an embodiment of the shield according to the invention against electromagnetic interference sources is used in particular for shielding against magnetic fields, such as are present, for example, in the case of cables through which current flows, in the vicinity of railway systems or in the vicinity of transformers.
• the particles of the ferromagnetic material can be attached to the metal support; it is also possible to coat the metal coating with the particles made of the ferromagnetic material. With the particles from the ferromagnetic see material, the shielding consisting of the fleece and the metal layer receives a certain permeability.
• Finely ground ferrite powder, ultra-fine iron particles and / or ultra-fine nickel particles can be used as the ferromagnetic material. This ensures that the material properties of the shield with regard to corrosion, breathability and elasticity are not impaired, so that it is ensured that all conceivable surfaces from building walls up to housing surfaces etc. are glued to the material according to the invention for shielding against electromagnetic interference sources can be disguised.
• the shield is provided with a glass fiber layer.
• Such material for shielding against electromagnetic interference can then be stored and transported in rolls in a similar manner to conventional wallpapers become; Handling, as in the case of wallpaper, is also possible if such a material is to be used for shielding against electromagnetic interference sources for shielding a room or a room.
• the glass fiber layer is designed as a glass fiber wallpaper and arranged on the front of the shield.
• the material combined with this wallpaper for shielding against electromagnetic interference can be applied to ceilings and walls of rooms to be shielded in one operation. This results in considerable advantages compared to solutions in which a wallpaper is applied to the shielding previously applied to the wall surfaces.
• the shielding combined with a glass fiber wallpaper offers considerable advantages insofar as such glass fiber wallpapers can be cleaned well, which is particularly true in public areas, e.g. with authorities and institutions of all kinds and in hospitals.
• the joining of the fleece and the metal coating and the glass fiber wallpaper or the glass fiber layer can be achieved in a simple manner if the shield is laminated or pressed together with the glass fiber layer.
• the shield comprising the fleece and the metal pad is designed as a self-adhesive material is.
• a self-adhesive design of the material forming the shielding has significant advantages, since otherwise the usual wet gluing would be required.
• the design as a self-adhesive material has considerable advantages, since it can be used, for example, on surfaces on which wet adhesives normally used for gluing do not adhere properly, such as on glass or on ceramic materials such as tiles .
• damage that occurs during the useful life of the shield which is related, for example, to drilling or nailing through the shield, can be repaired quickly and easily by simply pasting the damaged area with the self-adhesive material.
• the application of such a self-adhesive shield in places that are difficult to access, for example in the ceiling area of a room is considerably easier to accomplish than the application of a non-self-adhesive material for which a wet adhesive would have to be used.
• a pH-neutral adhesive is used as the adhesive.
• the shielding described above can be grounded in a simple manner by contacting by means of screws with toothed lock washers.
• the shield is provided on its free surface with an insulating and voltage-resistant protective layer.
• Shielding according to the invention against electromagnetic interference sources e.g. against high-frequency transmitters common in radio, taxi or police, consists of a fleece made of synthetic fibers, yarns or the like. and from a metal pad that each fiber, yarn or the like. of the fleece encased all around.
• the fleece has a basis weight of 10 to 40, the metal layer one of 25 to 70 g / m 1 .
• the fleece is made as a spunbond from swirled endless filaments made of polyamide 6/6 (nylon).
• the thickness of the filaments forming the fleece is between 2 and 20 dtex.
• the metal coating surrounding every fiber or yarn of the spunbonded nonwoven is made of copper and / or of silver or of copper and nickel or of copper and tin and is coated with a surface of a two-component ten-acrylate copolymer. This provides protection of the metal coating against damaging influences such as corrosion and galvanic corrosion, without the surface conductivity of the metal coating being impaired.
• the metal coating has particles of ferromagnetic material which are attached to it or with which it is coated. Finely ground ferrite powder can be used as the ferromagnetic material; finest iron particles and / or finest nickel particles are also possible.
• Alloys containing ferrites, iron or nickel can also be provided in very fine particles, which are so-called ⁇ -metals with a very high permeability. This can be used to shield magnetic fields, such as those that occur in cables through which current flows, in the vicinity of railway systems or in the vicinity of transformers. It is only through this ferromagnetic material that sufficient shielding of rooms, housings, cables and plugs can be guaranteed in the low-frequency range below 1 MHz. Such material is used in small or very fine particles in order not to impair the mechanical properties of the material forming the shield against electromagnetic interference sources.
• the material forming the shield against electromagnetic interference sources can be laminated with a glass fiber layer, in particular with a glass fiber wallpaper his. This results in an increased rigidity and a "simplification when using such materials.
• a shield combined with a glass fiber wallpaper can be rolled out like a normal wallpaper; its further handling is similar to that of a wallpaper, in addition, in one operation, the material forming the shield In addition to the wallpaper covering it, it can be attached to a wall surface.
• Such shields coated with a glass fiber wallpaper on their free surface can be cleaned and kept clean with little effort. That is why they are often used by authorities, institutions of all kinds and hospitals.
• the shield consisting of the fleece and the metal coating is designed as a self-adhesive material.
• Such an embodiment is particularly useful when shielding device housings because it makes wet gluing superfluous. Almost all of them today for housings or the like. Materials used can be glued with such self-adhesive shielding without any problems.
• Self-adhesive shielding is also advantageous when shielding rooms that are partially delimited by glass or ceramic material, such as tiles, since it can also be firmly attached to surfaces on which wet adhesives do not adhere properly. Any damage to the shielding can be easily removed by simply sticking it over. In addition, the attachment in places that are difficult to access, considerably easier compared to wet tying.
• a pH-neutral adhesive is used as the adhesive, so that negative effects on the actual shielding are avoided.
• the free surface of the shield is provided with an insulating and voltage-resistant protective layer, so that there is a necessary protection against accidental contact.

Applications Claiming Priority (3)

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• 1997
  • 1997-03-21 DE DE1997112043 patent/DE19712043A1/de not_active Withdrawn
• 1998
  • 1998-03-21 EP EP98917041A patent/EP0968633A1/de not_active Withdrawn
  • 1998-03-21 WO PCT/EP1998/001657 patent/WO1998043469A1/de not_active Application Discontinuation

Non-Patent Citations (1)

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