JP2920901B2 - Shielded wire - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric wire coated with a shielding material for electromagnetic waves, that is, a so-called shielded electric wire, and more particularly to a shielded electric wire excellent in salt water resistance.

[0002]

2. Description of the Related Art Conventional shielded electric wires include, for example, FIG.
As shown in FIG. 1, there has been proposed a material in which a polymer film-laminated aluminum tape b is coated as a shielding material around a core wire a, and a protective layer c is formed on the outside of the core (a).
No. 153441). As shown in FIG. 5, the polymer film-laminated aluminum tape b is a tape-shaped laminate of an aluminum foil d for shielding and a thermoplastic synthetic resin layer e such as a polyester film. The other surface of e is provided with an adhesive layer f for adhering to the protective layer c. Then, the core wire a and the drain wire g are wound around with the aluminum foil d inside, thereby forming a shielded electric wire having a structure as shown in FIG.

However, aluminum foil tapes such as the above-mentioned polymer film-laminated aluminum tape b have low salt water resistance, so that when used in an environment having salt damage, the aluminum foil is corroded, the shielding characteristics are degraded, and failure occurs. There is a risk. In particular, there is a problem that cannot be adopted in terms of reliability in an environment such as in an engine room of an automobile where salt damage must be sufficiently considered.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and has as its object to provide a highly reliable shielded wire having high durability, particularly excellent salt water resistance. I do.

[0005]

According to a first aspect of the present invention, there is provided a shielded electric wire comprising a conductive core wire covered with a shielding material having a metal foil. The shielding material is directly applied as a carbon material to the surface of the metal foil of the composite sheet obtained by laminating the thermoplastic resin sheet and the metal foil.
Vapor-phase grown carbon having a diameter of 0.5 μm or less and a length of 50 μm or less
A conductive resin composite material layer containing fibers and having a thickness of 1 to 100 μm is provided. The conductive resin composite
The thickness of the material layer is preferably 3 to 50 μm (claim 2).

[0006] The vapor-grown carbon fiber as a carbon material used in the present invention includes, for example, hydrocarbon compounds such as aromatic hydrocarbons such as toluene, benzene and naphthalene, and aliphatic hydrocarbons such as propane, ethane and ethylene; Preferably, benzene or naphthalene is used as a raw material, and the raw material is gasified to 900-1% with a carrier gas such as hydrogen.
Catalyst made of ultrafine metal at 500 ° C., for example, having a particle size of 10
Contacting or decomposing iron or iron-nickel alloy of 0 to 300 angstroms on a substrate made of ceramic, graphite, or the like, or gasifying such a raw material and 900 to 1500 together with a carrier gas such as hydrogen.
The catalyst can be obtained by contacting or decomposing a catalyst made of ultrafine metal dispersed and suspended in a reaction zone at a temperature of, for example, iron or an iron-nickel alloy having a particle size of 100 to 300 angstroms.

[0007] The vapor grown carbon fiber thus obtained is usually
The diameter is 1.0 μm or less and the length is 50 μm or less, but can be pulverized using a ball mill, a rotor speed mill, a cutting mill or other pulverizers as necessary,
To be 0.5 μm or less in diameter and 50 μm or less in length,
When compounded with a thermoplastic resin, it is effective to enhance dispersibility and conductivity. Further, another carbon-based filler may be added to the vapor-grown carbon fiber, and if necessary, additives such as a tackifier, a plasticizer, and an antioxidant may be added.

As the thermoplastic resin, for example, a saturated polyester copolymer, a polyolefin, an ethylene / vinyl acetate copolymer resin, a diene / styrene copolymer resin, an acrylic resin and the like are preferable.

The conductive resin composite material containing a carbon material according to the present invention is obtained by mixing and dispersing the above-mentioned carbon material preferably in an amount of 10 to 200 parts by weight, based on the above-mentioned thermoplastic resin.

In order to provide the above-mentioned conductive resin composite material layer on the surface of the metal foil of the composite sheet obtained by laminating the thermoplastic resin sheet and the metal foil, it is necessary to apply the conductive resin composite material directly to the composite sheet in a molten state of the thermoplastic resin. Alternatively, the coating may be performed in a state diluted with an appropriate solvent. As an application means, any applicator such as a comma coater or a gravure coater may be used.

The thickness of the conductive resin composite material layer is 1 μm to 1 μm.
If it is thinner than this, the corrosion prevention effect of the coating is impaired, and if it is thicker, the resistance at the time of electrical connection with the drain line increases, and the shielding effect becomes insufficient.

[0012]

The shielded electric wire of the present invention has a carbon material having a diameter of 0.5 μm or less and a length of
It contains vapor grown long carbon fiber of 0 μm or less and has a thickness of 1 to 1
Because the conductive resin composite material layer of 00 μm is provided, the metal foil of the shielding material is not oxidized or corroded, and the conductive resin composite material layer surely contacts the drain line,
Given bending or vibration is also not impaired conduction has a high durability and reliability, especially salt water is much better.

[0013]

FIG. 1 is a perspective view showing the structure of a shielded electric wire A according to an embodiment of the present invention. The shielded electric wire A has a structure in which the outside of the conductive core wire 1 is covered with a shielding material 2 and the outside is further covered with a protective layer 3. 4 is a drain line. The conductive core wire 1 is formed by covering an electric wire 1a with an insulating material 1b.

As shown in FIG. 2, the shielding member 2 includes a polyester film 5, an aluminum foil 6, a conductive resin composite material layer 7,
It is composed of an adhesive layer 8. That is, on the surface of the aluminum foil 6 of the composite sheet 9 (aluminum foil tape) formed by laminating the aluminum foil 6 on one side of the polyester film 5,
It is formed by coating a conductive resin composite material layer 7 containing a carbon material. The adhesive layer 8 is applied to adhere to the protective layer 3.

The preparation of the shielding material 2 was performed as follows.
Metal iron catalyst particles having a particle diameter of 100 to 300 angstroms are suspended while flowing hydrogen from below in a vertical tubular electric furnace controlled at a temperature of 1000 to 1100 ° C., and a mixed gas of benzene and hydrogen is added thereto from below. It was introduced and decomposed to obtain carbon fibers having a length of 1 to 30 μm and a diameter of 0.01 to 0.5 μm. Next, this carbon fiber was ground using a planetary ball mill (Fritsch Japan KK, P-5 type) at a rotation speed of 500 rpm for 20 minutes. Further, this ground carbon fiber is put into an electric furnace, and is heated to 296 in an argon atmosphere.
The mixture was graphitized by being kept at 0 to 3000 ° C. for 30 minutes. The obtained graphitized vapor-grown carbon fiber had a diameter of 0.5 μm or less and a length of 1 to 50 μm.

The above-mentioned graphitized vapor-grown carbon fiber is blended with a saturated polyester copolymer (Elitel UE-3220, manufactured by Unitika Ltd.) so that the blending amount becomes 50% by weight, and becomes 50% by weight with toluene. aluminum conductive resin composite solution obtained by diluting, by applying to the composite sheet (aluminum foil tape) 9 surface of the aluminum foil 6 of using a comma coater, a thickness of 10 m to 50 m, as a conductive as The shielding material 2 having the conductive resin composite material layer 7 having a surface resistance of 1 Ω / cm ² or less including the foil 6 was formed. The conductive core wire 1 and the drain wire 4 are wrapped around the shielding material 2,
Further, by covering the outside with a protective layer 3, FIG.
As a result, a shielded electric wire A was obtained as shown in FIG.

The above conductive resin composite material solution is mixed with a composite sheet (aluminum foil tape) 9 using a gravure coater.
3 μm thick by coating on the surface of aluminum foil 6
A shielding material having a conductive resin composite material layer having a surface resistance of 1 Ω / cm ² or less including aluminum foil 6 as a conductive material was formed. The conductive core wire 1 and the drain wire 4 were wound around with this shielding material, and the outside thereof was further covered with a protective layer 3, whereby a shielded electric wire A 'was produced.

Shielded wire A and shielded wire A '
In each case, the surface of the aluminum foil 6 is made of a conductive resin composite material layer 7.
Because it is covered with, there is no corrosion of the aluminum foil 6, particularly and salt water resistance good, yet it is less costly advantages lightweight. Further, as shown in FIG. 3, since the conductive resin composite material layer 7 is in close contact with the periphery of the conductive core wire 1 and the drain wire 4, the drain wire 4 and the aluminum foil can be bent even when bent. 6, and a reliable shielding effect is obtained.

[0019]

The shielded electric wire of the present invention has a carbon material having a diameter of 0.5 μm or less on the surface of the metal foil of the composite sheet .
Including vapor-grown long carbon fiber having a length of 50 μm or less, and having a thickness of
Since the conductive resin composite material layer of 1 to 100 μm is provided, the metal foil of the shielding material does not undergo oxidation or corrosion,
Durability, especially salt water resistance, is remarkably excellent. Further, since the conductive resin composite material layer surely comes into contact with the built-in drain line, there is an advantage that conduction is not impaired even if bending or vibration is applied, and shielding performance and reliability are remarkably improved.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a structure of a shielded electric wire according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view of the shielding member of FIG.

FIG. 3 is a sectional view of the shielded electric wire of FIG. 1;

FIG. 4 is a perspective view of a conventional shielded electric wire.

FIG. 5 is a cross-sectional view of the polymer film-laminated aluminum tape of FIG.

[Explanation of symbols]

 A shielded electric wire 1 conductive core wire 2 shielding material 6 aluminum foil 7 conductive resin composite material layer 9 composite sheet

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-4-4517 (JP, A) JP-A-3-131026 (JP, U) (58) Fields investigated (Int.Cl. ⁶ , DB name) H01B 11/06 H01B 7/18

Claims (2)

(57) [Claims] 1. A shielded electric wire comprising a conductive core wire covered with a shielding material having a metal foil, wherein the shielding material is formed on a surface of a metal foil of a composite sheet obtained by laminating a thermoplastic resin sheet and a metal foil. 0.5 μm or less in diameter and 5 in length as carbon material
It contains vapor-grown long carbon fibers of 0 μm or less and has a thickness of 1 to 10
A shielded electric wire provided with a conductive resin composite material layer of 0 μm . 2. The conductive resin mixture layer has a thickness of 3 to 50.
The shielded wire according to claim 1, which has a thickness of μm .