JP2016115510A - Electrical line, shield wire and multicore cable using it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide fire-resistant electrical line having all of sufficient voltage endurance, mechanical property and wear resistance.SOLUTION: There is provided an electrical line 1 comprising conductor 2, first insulation layer (inner layer) 3 covering the conductor 2, and second insulation layer (outer layer) 4 covering the first insulation layer 3. The first insulation layer 3 contains polyethylene and adhesive agent. The second insulation layer 4 contains engineering plastic and flame retardant. All of the first insulation layer 3 and second insulation layer 4 are crosslinked.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an electric wire, a shielded electric wire using the same, and a multicore cable.

  Patent Document 1 discloses an insulated wire having a plurality of insulating coating layers, containing a polyphenylene ether-based resin in the inner layer or the outer layer of the plurality of insulating coating layers, and having excellent damage resistance and wear resistance. A flame retardant insulated wire suitable for use is described.

JP 2009-301766 A

However, the electric wire as described in Patent Document 1 cannot satisfy all of voltage resistance, mechanical properties, and wear resistance.
An object of the present invention is to provide a flame-retardant electric wire that can satisfy all of voltage resistance, mechanical properties, and wear resistance.

The electric wire according to one aspect of the present invention is an electric wire having a conductor, a first insulating layer covering the conductor, and a second insulating layer covering the first insulating layer, wherein the first insulating layer is made of polyethylene. And an adhesive, the second insulating layer contains an engineering plastic and a flame retardant, and both the first insulating layer and the second insulating layer are cross-linked.
The shielded electric wire which concerns on another one aspect | mode of this invention is a shielded electric wire which has the said electric wire, an external conductor, and the jacket of those circumference | surroundings.
A multi-core cable according to another aspect of the present invention includes a plurality of the electric wires, a collective shield layer that covers the periphery of the plurality of electric wires, and a jacket that covers the periphery of the collective shield layer. It is a multicore cable.

  According to the present invention, it is possible to provide a flame-retardant electric wire that can satisfy all of voltage resistance, mechanical properties, and wear resistance.

It is a schematic sectional drawing which shows an example of the electric wire of this invention. It is a schematic sectional drawing which shows an example of the shielded electric wire using the electric wire of this invention. It is a schematic sectional drawing which shows an example of the multi-core cable using the electric wire of this invention.

[Description of Embodiment of Present Invention]
The electric wire according to one aspect of the present invention is (1) an electric wire having a conductor, a first insulating layer covering the conductor, and a second insulating layer covering the first insulating layer,
The first insulating layer contains polyethylene and an adhesive;
The second insulating layer contains an engineering plastic and a flame retardant;
Both the first insulating layer and the second insulating layer are cross-linked.

In order to satisfy the voltage resistance requirement of the electric wire, a plurality of insulating layers covering the conductor are used, and polyethylene (hereinafter also referred to as PE) is used on the conductor side, that is, the inner layer.
In addition, in order to satisfy the requirements of mechanical properties and wear resistance of electric wires, engineer plastics such as thermoplastic resins having one or more of an amide bond, an ester bond or a urethane bond on the outer layer of a plurality of insulating layers (Hereinafter also referred to as engineering plastic) is used.
However, an electric wire having an insulating layer composed of an inner layer containing PE and an outer layer containing engineering plastic has a problem that wear resistance is lowered.
Therefore, in this embodiment, by including an adhesive in the inner layer containing PE, that is, the first insulating layer, it is possible to satisfy all of the voltage resistance, mechanical properties, and wear resistance, and the flame-retardant property. It was possible to use an electric wire.

(2) It is preferable that mass ratio (polyethylene: adhesive) of polyethylene and an adhesive contained in the first insulating layer is 4: 6 to 6: 4. Within this mass ratio range, the wear resistance and the voltage resistance are more preferable.
(3) It is preferable that content of the engineering plastic in the said 2nd insulating layer is 50-86 mass%. If it is this content range, it will be in a state with more preferable abrasion resistance.

(4) It is preferable that the cross-sectional area of the conductor is 0.5 mm ² or more and 2.0 mm ² or less. It is a suitable size as an electric wire mounted on a vehicle.
(5) It is preferable that the thickness of the first insulating layer is 0.04 mm or more and 0.06 mm or less. It is a suitable size as an electric wire mounted on the vehicle, and can satisfy all of voltage resistance, mechanical properties, and wear resistance.
(6) The electric wire of the present embodiment can be a shielded electric wire by providing the electric wire, an external conductor, and a jacket around them.
(7) Moreover, the electric wire of the said embodiment is provided with a plurality of the electric wires, a collective shield layer covering the periphery of the plural electric wires, and a jacket covering the periphery of the collective shield layer. It can be a core cable.

[Details of the embodiment of the present invention]
Hereinafter, embodiments of the present invention will be described in detail.
(Outline of electric wire)
Hereinafter, an embodiment of the present invention will be described in detail with reference to FIG.
(Outline of insulated wire)
FIG. 1 is a schematic cross-sectional view illustrating an example of an electric wire that is an embodiment of the present invention.
The electric wire 1 has a conductor 2 and at least two insulating layers of a first insulating layer (hereinafter also referred to as an inner layer) 3 and a second insulating layer (hereinafter also referred to as an outer layer) 4 on the outer periphery of the conductor 2. The first insulating layer 3 is in close contact with the conductor 2 and the second insulating layer 4.

(Inner layer)
The inner layer 3 contains polyethylene and an adhesive.
The polyethylene used for the inner layer 3 is not particularly limited, and may be either high-density polyethylene (HDPE) or low-density polyethylene (LDPE), and an appropriate one may be selected according to the specifications of the electric wire 1. .
The adhesive used for the inner layer 3 is not particularly limited, and examples thereof include glycidyl methacrylate (GMA), vinyl acetate (VA), or a copolymer of methyl acrylate (MA). An appropriate adhesive may be selected according to the specifications of the electric wire 1, polyethylene used for the inner layer 3, compatibility with a resin used for the outer layer 3 described later, and the like.
The mass ratio (polyethylene: adhesive) of polyethylene and adhesive contained in the inner layer 3 is not particularly limited, but is preferably 4: 6 to 6: 4.
The inner layer 3 may contain an antioxidant.
The thickness of the inner layer 3 is preferably 0.04 mm to 0.06 mm. There is a limit to the thickness of the electric wire, and when the inner layer is thickened, the outer layer described later may have to be made thinner accordingly. In the electric wire of the present invention, when the outer layer becomes thin, the wear resistance and flame retardancy may not be sufficient. For this reason, the upper limit of the thickness of the inner layer is preferably 0.06 mm. In detail, what is necessary is just to select suitable thickness according to the specification of the electric wire 1, the polyethylene used for the above-mentioned inner layer 3, an adhesive agent, the resin used for the below-mentioned outer layer 4, and a flame retardant.

(Outer layer)
The outer layer 4 contains an engineering plastic and a flame retardant.
The engineering plastic used for the outer layer 4 is preferably a thermoplastic resin having any one or more of an amide bond, an ester bond and a urethane bond. It is more preferable that the thermoplastic elastomer has any one or more of an amide bond, an ester bond, and a urethane bond.
The content of the engineering plastic contained in the outer layer 4 is preferably 50 to 86% by mass, and more preferably 72 to 86% by mass.

  Examples of the flame retardant used for the outer layer 4 include metal hydroxides, nitrogen-based flame retardants, phosphorus-based flame retardants, and intumescent flame retardants. As for the flame retardant, an appropriate one may be selected according to the specifications of the electric wire 1, the polyethylene used for the inner layer 3, the adhesive, the compatibility with the engineering plastic used for the outer layer 4, and the like. Of these, nitrogen-based flame retardants and phosphorus-based flame retardants are preferred.

Further, the outer layer 4 may contain an antioxidant, an ion scavenger, a hydrolysis inhibitor, an ester lubricant, a crosslinking aid, a coloring material, and the like.
The thickness of the outer layer 4 is a thickness obtained by subtracting the thickness of the inner layer from the insulating layer thickness determined by the conductor outer diameter.

(conductor)
As the conductor 2, a general copper wire, a copper alloy wire, or the like can be used.
As the size of the conductor 2 is not particularly limited, use form of the electric wire 1, but is to be appropriately selected depending on the purpose or the like, those 0.5 to 2 mm ² is preferred as the cross-sectional area.

(Other)
As a use of the electric wire which is one form of this invention, it is preferable to apply to the control line for rail vehicles.
Moreover, in the electric wire 1 of embodiment shown in FIG. 1, although the conductor 2 of the single wire or the strand wire was used as the core and it had the inner layer 3 and the outer layer 4 in the circumference | surroundings, you may take another form.
For example, as shown in FIG. 2, the form of the shielded electric wire 10 having the electric wire 1 of the above-described embodiment, the outer conductor 11 that covers the periphery of the electric wire 1, and the jacket 12 that covers the outer periphery of the outer conductor 11, As shown in FIG. 3, a multicore cable having a plurality of the above-described electric wires 1 and having a collective shield layer 21 covering the periphery of the plurality of electric wires 1 and an outer cover 22 covering the periphery of the collective shield layer 21. Twenty forms are also possible.

Hereinafter, the results of evaluation tests using examples and comparative examples according to the present invention will be shown, and the present invention will be described in more detail. The present invention is not limited to these examples.
[Production of electric wire]
An electric wire was produced by covering the conductor with an insulating layer so as to have the configuration shown in Table 1 below.
The conductor was 19 twisted tin-plated annealed copper wires with a diameter of 0.254 mm, and had an outer diameter of 1.270 mm and a cross-sectional area of 0.963 mm ² .
The thickness of the insulating layer for the electric wire having this dimension was set to 0.050 mm for the inner layer and 0.175 mm for the outer layer in the case of the two-layer structure, and 0.225 mm in the case of the single-layer structure.

[Evaluation of electric wires]
About the produced electric wire, abrasion resistance, withstand voltage property, and a flame retardance were evaluated with the following method. The results are shown in Table 1 below.
(Abrasion resistance)
Scrape abrasion test: A scrape abrasion test was performed based on the provisions of ISO 6722: 2006. The blade material was a piano wire of φ0.45 mm, and the load was 9N. The number of reciprocating movements of the blade until the conductor was exposed was observed, and 150 times or more was passed and less than 150 times was rejected. The results are shown in Table 1 below.
(Withstand voltage)
DC stability (DC stability): DC 300V is applied for 240 hours in 85% C, 3% NaCl aqueous solution, current is measured every 24 hours, voltage of AC 2 kV is applied for 1 minute, and there is no dielectric breakdown One was A, and one with dielectric breakdown was B. The results are shown in Table 1 below.
(Flame retardance)
1 flame retardant test: 45 degree inclination test based on ISO6722. Those that self-extinguished were considered acceptable. The results are shown in Table 1 below.
In Table 1 below, no. Nos. 1 to 9 are examples. 10 to 12 are comparative examples.

  *: The composition of the insulating layer in Table 1 is as shown in Tables 2 and 3 below.

  In Tables 2 and 3, all numerical units are parts by mass.

  No. 1 to 9 (Examples) were excellent in all of wear resistance, voltage resistance and flame retardancy. No. No. 10 (Comparative Example) was an example in which there was no adhesive in the inner layer, and was excellent in voltage resistance and flame retardancy but inferior in wear resistance. No. 11 (Comparative Example) was an example in which an engineering plastic was used with an insulating layer having a single layer structure, which had excellent wear resistance and flame retardancy but was inferior in voltage resistance. Comparative Example 3 was an example in which polyethylene was used with an insulating layer having a single layer structure, and was excellent in voltage resistance but inferior in wear resistance and flame retardancy.

DESCRIPTION OF SYMBOLS 1 Electric wire 2 Conductor 3 Inner layer 4 Outer layer 10 Shielded electric wire 11 Outer conductor 12 Outer sheath 20 Multi-core cable 21 Collective shield layer 22 Outer sheath

Claims (7)

A conductor, a first insulating layer covering the conductor, and a second insulating layer covering the first insulating layer,
The first insulating layer contains polyethylene and an adhesive;
The second insulating layer contains an engineering plastic and a flame retardant;
An electric wire in which both the first insulating layer and the second insulating layer are cross-linked.   The electric wire according to claim 1, wherein a mass ratio (polyethylene: adhesive) of polyethylene and adhesive contained in the first insulating layer is 4: 6 to 6: 4.   The electric wire according to claim 1 or 2, wherein the content of the engineering plastic in the second insulating layer is 50 to 86 mass%. The electric wire according to any one of claims 1 to 3, wherein a cross-sectional area of the conductor is 0.5 mm ² or more and 2.0 mm ² or less.   The electric wire according to any one of claims 1 to 4, wherein the first insulating layer has a thickness of 0.04 mm to 0.06 mm.   A shielded electric wire comprising the electric wire according to any one of claims 1 to 5, an outer conductor, and a jacket around them.   A plurality of electric wires according to any one of claims 1 to 5, comprising a collective shield layer covering the periphery of the plurality of electric wires and an outer covering covering the periphery of the collective shield layer. Core cable.

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