JP2621470B2 - Manufacturing method of electric wire with shield layer - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for manufacturing an electric wire with a shield layer.

[Prior Art] Recent digital electronic devices are increasingly mounted with high density and tend to have higher precision and higher density, and measures against electromagnetic noise have become an important issue.

As a countermeasure against electromagnetic noise in electric wires wired to electronic devices as described above, there is generally a shield layer provided around the outer periphery of the electric wires. And, in order to form this shield layer, conventionally, a braid with a tin-plated copper wire, a copper tape winding, a coating of an aluminum pipe, a winding of a laminated tape in which aluminum or copper is vapor-deposited on a polyester tape, etc. It has been practiced to add a conductive composition in which an organic polymer is mixed with a conductivity-imparting agent such as carbon or metal powder, or the like.

[Problems to be Solved by the Invention] However, the above-mentioned conventional shield means have the following problems, respectively, and are limited in application.

Braiding with tin-plated copper wire takes a lot of time and effort in manufacturing, and is problematic in terms of productivity.

Copper tape winding and aluminum pipe coating not only have poor flexibility, but also have a problem that cracks and the like are easily generated. Also, they are difficult to apply to small size cables. A laminated tape obtained by depositing copper or aluminum on polyester or the like is a relatively preferable material without the above-mentioned problems. However, it is difficult to firmly bond the overlapping portions of the tape, and there is a drawback that electrical contact between copper or aluminum portions cannot be obtained at the overlapping portions.

A material obtained by mixing an organic polymer with a conductivity-imparting agent such as carbon or metal has good adhesive workability, but is inadequate to obtain a complete shielding effect.

As described above, each of the conventional shielding means has advantages and disadvantages, and in reality, an appropriate shielding technique that can be sufficiently expected from the viewpoint of manufacturing or effect has not yet been found.

The present invention solves the above-mentioned problems of the prior art, has a very good production efficiency, can easily perform mechanical and electrical connection of the overlapping portion, and can enhance the electromagnetic shielding effect. An object of the present invention is to provide a method for manufacturing a layered electric wire.

[Means for Solving the Problems] The gist of the present invention is to laminate a heat-fusible conductive rubber or plastic layer having a volume resistivity of 10 ⁶ Ω · cm or less on a metal layer having a thickness of 1 μm or more and 100 μm or less. The fused conductive composite tape is coated on the outer periphery of the wire core as a shield layer, and the edge overlapping portion of the composite conductive tape is sandwiched by electrodes,
There is provided a method for manufacturing an electric wire with a shield layer, characterized in that the overlapped portion is heated by an energizing current to be thermally fused.

The thicker the metal layer, the greater the shielding effect, but it is not preferable to make the metal layer too thick because the flexibility is reduced. 1
A thickness in the range of 範 囲 100 μm is suitable, more preferably a thickness of 3-20 μm. Such a metal layer can be formed by, for example, vapor deposition or plating, or laminating a metal foil. It is desired that the heat-fusible rubber or plastic conductive layer has a volume resistivity of 10 ⁶ Ω · cm or less in order to secure electrical contact. Preferably 10 ³
Ω · cm or less, more preferably 10 ² Ω · cm or less.

Actually carbon black on rubber or plastic,
A heat-fusible conductive layer can be formed by mixing graphite, metal powder, carbon fiber, metal fiber, and the like. The thickness is preferably from 5 μm to 1 mm. As the rubber / plastic, a material having high strength is preferable, but is not particularly limited. For example, polyester, ionomer resin, ethylene ethyl acrylate resin, polystyrene, polyethylene, polyvinyl acetate, polyvinyl chloride,
Polyvinylidene fluoride, polypropylene, butyl rubber,
Examples include, but are not limited to, isoprene rubber, ethylene propylene rubber, polyamide, cellulosic resin, fluororesin, and polyurethane.

[Function] In the present invention, a composite conductive tape formed by laminating and fusion-bonding a conductive rubber or plastic layer capable of being thermally fused to a metal layer is used. Fusing is possible, and mechanical joining and electrical connection can be achieved in a highly productive manner.

[Example] Hereinafter, the present invention will be described with reference to examples.

FIG. 1 is a cross-sectional view showing an embodiment of a composite conductive tape 10 according to the present invention, wherein 1 is a metal layer, and 2 is a heat-fusible conductive rubber or plastic conductive layer.
In this embodiment, an example of a two-layer structure is shown, but the invention is not limited to two layers. If necessary, a three-layer or four-layer structure may be used.

FIG. 2 is a cross-sectional view showing a specific example of the shielded electric wire according to the present invention in which the composite tape 10 configured as described above is covered around the insulated wire core having the insulator 4 on the conductor 3. FIG. Although the figure shows the case of vertical attachment, it goes without saying that an appropriate method such as winding or horizontal winding may be used.

If the tape 10 is covered as shown in FIG. 2, the joining portion 10A at the edge is inevitably formed. Heretofore, it has been difficult to electrically and conveniently connect such joints in a composite tape.

In the present invention, for example, as shown in FIG. 3, the joint 10A is sandwiched between the electrodes 20 and 20, and a current supplied from the power supply 21 causes the joint 10A to generate heat. In this way, the heat-fusible conductive layer 2 causes heat fusion, whereby mechanical bonding and electrical connection can be achieved at the same time, and an ideal shield layer can be formed. . In addition, since only local heating is required, there is no fear that extra heat is exerted on the neighboring insulator 4, and complete mechanical and electrical connection with high production efficiency can be realized.

Example 1 70 parts by weight of acetylene carbon (product of Denki Kagaku) was mixed with 100 parts by weight of an ionomer resin (Himilan 1557, melt index MI = 5.0, density d = 0.95, product of Mitsui DuPont Polychemicals Co., Ltd.), and the thickness was 0.2 A 30 mm thick copper tape was heated and adhered to one side at the same time to obtain a heat-fusible composite conductive tape having a structure shown in FIG. 1 and having a width of 15 mm. The volume resistivity of the conductive resin layer was 6 × 10 Ω · cm.

The obtained tapes were superimposed on each other as shown in FIG. Then, the adhesive portion was pulled to examine the mechanical adhesion, and the electrical conductivity of the upper layer and the lowermost layer in FIG. 3 was examined by a tester. The results are shown in Table 1. From the table, it can be seen that good adhesion can be obtained both mechanically and electrically. In addition, the tape was covered with an electric wire having an outer diameter of 1.2 mm as shown in FIG. 2 and the flexibility was examined after the overlapping portion was fused. The result was very good.

Example 2 Aclift WD310 (MI = 7, d = 0.93) as a resin
A conductive compound was prepared in the same manner as in Example 1 using Sumitomo Chemical Co., Ltd.) and formed into a 0.15 mm thick tape. Next, copper is deposited by evaporation.
It was laminated to a thickness of μm. Table 1 shows the results of evaluation performed in the same manner as in Example 1. The mechanical and electrical adhesion is good and the flexibility of the electric wire is sufficient.

Example 3 0.1 mm of conductive PVC SP-7130 (d = 1.27 made by Riken Vinyl)
Using a thick film, a tape in which copper was laminated by 12 μm by a plating method was obtained. As a result of evaluation in the same manner as in Example 1, a suitable shielded electric wire could be obtained as shown in Table 1.

Comparative Example 1 Copper-deposited polyester film having a thickness of 10 μm (thickness of 20 μm)
m, a commercially available product). However, no adhesion could be made mechanically or electrically.

Comparative Example 2 A 0.15 mm thick Himilan tape was thermally fused to a 200 μm thick copper tape, and the same evaluation as in Example 1 was performed.
As a result, electrical and mechanical connections could not be obtained.

As described above, the tape according to the present invention basically has a structure having a metal layer and an organic conductive layer that can be thermally fused, and the metal is copper, aluminum, brass, stainless steel, tin, lead, and various types. Any of alloys and plated composite metals may be used. The organic conductive layer may be subjected to flame retardation, cross-linking, etc., as long as it has heat-fusibility.

[Effects of the Invention] As described in detail above, according to the present invention, it is possible to obtain a shielded wire having both a shielding effect, adhesive workability, and electrical and mechanical reliability with high productivity. In addition, the range of industrial applications is extremely wide, such as application even when the wire size is small, and its industrial value is large.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing an embodiment of the composite tape according to the present invention, FIG. 2 is a cross-sectional view of a shielded electric wire using the composite tape, and FIG. 3 is an explanatory view showing a fusion bonding state according to the present invention. It is. 1: metal layer, 2: heat-fusible conductive layer, 3: conductor, 4: insulator
10: Composite tape, 10A: Tape joint, 20: Electrode, 21: Power supply.

 ──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Hidemi Sasaki 5-1-1, Hidaka-cho, Hitachi City, Ibaraki Pref. JP-A-61-61305 (JP, A) JP-A-57-178306 (JP, U) JP-A 64-1702 (JP, Y2)

Claims (1)

(57) [Claims] 1. A composite conductive tape comprising a metal core having a thickness of 1 μm or more and 100 μm or less and a heat-fusible conductive rubber or plastic layer having a volume resistivity of 10 Ω · cm or less laminated and fused to a metal core. Characterized in that the outer periphery of the composite conductive tape is covered as a shield layer, the edge overlap portion of the composite conductive tape is sandwiched between electrodes, and the overlap portion is heated by an electric current to be thermally fused. Manufacturing method of electric wire.