JPH10145080A - Electromagnetic shield tape and electromagentically shielded wire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stably hold an initial electromagnetic shield effect by providing a metal deposited layer on one surface of a support film and a metal powder- contg. conductive adhesive layer on the metal deposited layer. SOLUTION: On one side of a polyethyleneterephthalate, polybutyleneterephthalate or other polyester plastic support film 1 an Al, Cu, Au or other metal vacuum evaporated layer 2 is provided. A conductive adhesive composed of a thermoplastic polyester resin soln. 100wt. parts, cross-linking agent 1wt. part and Ni powder 100wt. parts is applied to the metal evaporated layer 2 on the film 1 and heat treated to form a conductive adhesive layer 3 to obtain an electromagnetic shield tape. This provides a stable electromagnetic shield effect.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electromagnetic shield tape and an electric wire shielded by the electromagnetic shield tape.

[0002]

2. Description of the Related Art Electromagnetic interference (EMI) is required for electric wires, flat cables, and the like, which have been widely used with the spread of OA equipment and the development of LANs. Thus,
It is known that a flat cable or the like is surrounded by an electromagnetic shield tape to provide an electromagnetic shield function to the flat cable or the like itself. Electromagnetic shield effect SE by metal layer
Are the absorption loss that is absorbed as heat loss in the path through which the electromagnetic wave propagates through the metal layer, the reflection loss caused by reflection when a different medium is present in the propagation path of the electromagnetic wave, and the repetition of reflection at both ends of the metal layer The absorption loss A is given by A∝t√ (fδμ) where t is the thickness of the metal layer, δ is the conductivity, μ is the magnetic permeability, and f is the frequency. Conventionally, an electromagnetic shield tape in which a metal deposition layer is provided on one side of a plastic support film and an adhesive layer is provided on the metal deposition layer, a metal foil is adhered to one side of the plastic support film, There are known those in which an adhesive layer is provided on a foil.

[0003]

The electromagnetic shielding effect of these electromagnetic shielding tapes is mainly exerted by absorption loss, and as is apparent from the above equation, the greater the thickness t of the metal layer, the greater the thickness. Also, as the conductivity δ increases, the electromagnetic
Field effect increases. Generally, the thickness of the metal foil (usually several μm to several tens of μm) depends on the thickness of the metal deposition layer (usually,
1 μm or less, and the conductivity of the metal foil is considerably higher than the conductivity of the metal-deposited layer (the metal-deposited layer is a porous material in which evaporated metal molecules are bonded through gaps). Body, which has lower conductivity than dense metal foil)
Therefore, an electromagnetic shield tape using a metal foil for the metal layer has a larger absorption loss A than the electromagnetic shield tape using a metal deposition layer for the metal layer, and has an electromagnetic shield effect. Is high.

However, a dense metal foil has a higher rigidity than a porous metal vapor-deposited layer, and is an electromagnetic shield tape using a metal foil for the metal layer, such as a flat cable or the like.
When the shield layer is formed, cracks are generated in the metal foil due to repeated bending of a flat cable or the like, and there is a concern that the electromagnetic shielding effect is significantly reduced. On the other hand, if an electromagnetic shield layer such as a flat cable is formed by an electromagnetic shield tape using a metal vapor-deposited layer as the metal layer, the decrease in the electromagnetic shield effect due to the generation of cracks described above can be eliminated. The initial electromagnetic shield effect is low, and it is difficult to guarantee a satisfactory electromagnetic shield.

An object of the present invention is to provide a flat cable or the like with a sufficiently high initial electromagnetic shielding effect and a flat cable.
An object of the present invention is to provide an electromagnetic shield tape capable of stably maintaining its initial electromagnetic shield effect even under repeated bending of a cable.

[0006]

An electromagnetic shield tape according to the present invention is provided with a metal deposition layer on one side of a support film.
The present invention is characterized in that a conductive adhesive layer to which metal powder is added is provided on the metal deposition layer. The electromagnetic shield according to the present invention
The electromagnetic shield according to claim 1, wherein the shielded electric wire comprises an insulating layer of the electric wire.
The tape is formed by surrounding the conductive adhesive layer surface of the tape inward with a tape, and bonding the conductive adhesive layer to the insulating layer.

[0007]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows an example of an electromagnetic shield tape according to the present invention. In FIG. 1, 1
Is a supporting film, and any suitable film can be used as long as it has appropriate rigidity suitable for bonding to a flat cable or the like, and it is preferable to use a plastic film. For example, films such as polyesters such as polyethylene terephthalate and polybutylene terephthalate, polyimides, polyethersulfone, polyetheretheroketone, polyphenylene sulfide, and polyarylate having a thickness of 10 to 150 μm. It can be suitably used. Reference numeral 2 denotes a metal deposition layer provided on one side of the plastic support film 1, for example, aluminum,
It can be provided by vacuum deposition of a metal such as copper or gold, and its thickness is usually 1 μm or less (1000 μm or less). This metal deposition layer can be provided on both sides of the plastic support film.

Reference numeral 3 denotes a conductive adhesive layer provided with a metal powder and provided on the metal deposition layer 2 on one side of the plastic supporting film, and includes a metal powder such as nickel, copper, aluminum, and the like.
An adhesive or a hot-melt adhesive to which a powder such as silver is added can be used, and in particular, it is preferable to use a thermoplastic polyester-based adhesive as a main component, and also an antioxidant,
An appropriate amount of a filler, a tackifier, a crosslinking accelerator and the like can be added. The thermoplastic polyester is a copolymer of at least one dicarboxylic acid and at least one diol (glycol).
Terephthalic acid, isophthalic acid, hexahydrophthalic acid,
Adipic acid; and diols such as ethylene glycol, diethylene glycol, propylene glycol, oxytetramethylene glycol, neopentyglycol, butanediol, and hexanediol. Can be In FIG. 1, reference numeral 4 denotes a release paper temporarily attached to the conductive adhesive layer 3.

FIG. 2 shows an example of an electric wire shielded by an electromagnetic shield tape according to the present invention. In FIG.
B denotes a flat cable main body, in which a plurality of parallel conductors 5,... Are sandwiched between upper and lower plastic films 6, 6, and these are integrated. C denotes an electromagnetic shield layer. The above-mentioned electromagnetic shield tape A is disposed on the upper and lower surfaces of the flat cable main body B with the conductive adhesive layer 3 inside, and the conductive adhesive layer 3 is hot. By applying heat and pressure in the case of the melt type, and by applying pressure in the case where the conductive adhesive layer 3 is an adhesive layer, by applying pressure between each electromagnetic shield tape A and the cable insulating layer 6 and by applying electromagnetic pressure. -A and A are bonded to each other.
The electric wire body may have a circular cross section. In this case, an electromagnetic shield layer may be formed along the length of the electromagnetic shield tape (accordingly, the electromagnetic shield tape has a wide width). Both ends overlap).

[0010]

【Example】

EXAMPLE Aluminum was vacuum-deposited on one side of a 25 μm thick polyethylene terephthalate film to a thickness of 300 μm. On this metallized layer, a thermoplastic polyester resin solution (Diabond D manufactured by Nogawa Chemical Co., Ltd.)
A-3080B) 100 parts by weight, 1 part by weight of a crosslinking agent (Diabond HFE, trade name, manufactured by Nogawa Chemical Co., Ltd.), and 100 parts by weight of nickel powder (carbonyl nickel, trade name, manufactured by Fukuda Metal Foil Powder Co., Ltd.) The adhesive A was applied, and a 40 μm-thick conductive adhesive layer was formed by heating at 130 ° C. for 1 minute to obtain an electromagnetic shield tape. Further, the electromagnetic shield tape was placed on both sides of a plastic insulated flat cable having a thickness of 1.0 mm, and heated and pressed at 150 ° C. for 30 seconds to produce an electromagnetic shield flat cable having the structure shown in FIG. did.

Comparative Example 1 100 parts by weight of a thermoplastic polyester resin solution (manufactured by Nogawa Chemical Co., trade name: Diabond DA-3080B) and a cross-linking agent (Nogawa Chemical Co., Ltd.) were placed on one side of a 25 μm-thick polyethylene terephthalate film. Adhesive B consisting of 1 part by weight (trade name, Diabond HFE) is applied, and an adhesive layer having a thickness of 10 μm is formed by heating at a temperature of 130 ° C. × 1 minute. Were bonded by heating and pressing at 150 ° C. × 30 seconds. The adhesive B was applied on the aluminum foil layer and heated at a temperature of 130 ° C. for 1 minute to form an adhesive layer having a thickness of 40 μm, thereby obtaining an electromagnetic shield tape. Further, this electromagnetic shield tape was placed on both sides of the above-mentioned plastic insulated flat cable, and heated and pressurized at 150 ° C. for 30 seconds to produce an electromagnetic shield flat cable having the structure shown in FIG. [Comparative Example 2] A conductive adhesive layer was formed by using the conductive adhesive A used in the example instead of forming the adhesive layer on the aluminum foil with the adhesive B in comparison with the comparative example 1. Except for this, it was the same as Comparative Example 1.

With respect to the electromagnetic shielded flat cables of these Examples and Comparative Examples, a repetitive bending test (reciprocating traveling of the flat cable in a U-shape along a half circumference of a 20 mmφ metal cylinder was performed 10,000 times) (Repeated), the electromagnetic shield tape was peeled off, and the occurrence of cracks in the metal layer was examined. In the flat cables of Comparative Examples 1 and 2, cracks were observed. No cracking occurred in the example flat cable. Further, regarding the electromagnetic shield tape after the repeated bending test, a shield material evaluation device (SP, manufactured by Takeda Riken Kogyo KK)
When the electromagnetic shielding effect at a frequency of 500 MHz was measured using ECTRUM ANALYZER TR17301), good results were obtained at 10 dB or more in the example, but 10% or more in Comparative Examples 1 and 2.
dB or less.

In the embodiment, despite the use of a metal deposition layer as the metal layer of the electromagnetic shield tape, a good electromagnetic shielding effect can be obtained because of the adhesive layer on the metal deposition layer surface. Metal powder is added to the adhesive layer to provide an electromagnetic shielding effect to the adhesive layer to enhance the overall electromagnetic shielding effect. This high electromagnetic shielding effect causes cracks in the metal deposition layer even under repeated bending. This is because it can be stably maintained without occurrence of the occurrence. In Comparative Example 2, despite the fact that the adhesive layer on the aluminum foil was a conductive adhesive layer, no satisfactory electromagnetic shielding effect was obtained because of the occurrence of cracks in the aluminum foil due to repeated bending. Therefore, it is presumed that the excellent electromagnetic shielding effect inherent to the aluminum foil was not exhibited.

[0014]

According to the present invention, when an electromagnetic shield layer is formed on an electric wire using the electromagnetic shield tape according to the present invention, even if the metal shield layer has a low electromagnetic shield effect, the electromagnetic shield layer can be formed by the conductive adhesive layer. −
The initial value of the electromagnetic shield can be increased by increasing the shielding effect, and the high initial electromagnetic shielding effect is maintained even under repeated bending of the wire due to the stability of the metal deposition layer and the conductive adhesive layer. it can. Therefore, according to the present invention, a high and stable electromagnetic shielding effect can be imparted to the electric wire.

[Brief description of the drawings]

FIG. 1 is a view showing an electromagnetic shield tape according to the present invention.

FIG. 2 is a view showing an electromagnetic shielded electric wire according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Support film 2 Metal deposition layer 3 Conductive adhesive layer A Electromagnetic shield tape B Electric wire main body

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI H01B 11/06 H01B 11/06

Claims (2)

[Claims] (1) providing a metal deposition layer on one side of a support film;
An electromagnetic shield tape comprising a metal powder-added conductive adhesive layer provided on the metal deposition layer. 2. The electromagnetic shield according to claim 1, wherein the insulation layer of the electric wire is provided.
An electromagnetic shielded electric wire, wherein the conductive adhesive layer surface of the tape is surrounded by a tape and the conductive adhesive layer is adhered to the insulating layer.