JPH0877838A - Insulated wire which is prevented from adhering conductor - Google Patents

Abstract

PURPOSE: To prevent the interlayer separation between two layers of outside and inside without drop of the insulating cover layer of an insulated cable or drop of mechanical strength by adopting the bridging method by an organic peroxide for the bridging of an inner insulating cover layer at least. CONSTITUTION: A composition for formation of an inner layer is obtained by mixing a peroxide, a filler, or the like to the material of ethylene - propylene rubber (EP rubber), butyl rubber or butyl rubber. EP rubber blend rubber. A composition for formation of an outer layer is obtained by mixing a cross linking agent, a filler, or other additive, etc., to this rubber material. This composition for formation of an inner layer and the composition for formation of an outer layer are supplied to a tandem extruder and are kneaded therein, and then two layers are extruded at the same time around a conductor 1 through a cross head part so as to form an inner layer 2 and an outer layer 3, and then those are crosslinked.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to prevention of adhesion of a conductor to an insulated wire, and particularly to prevention of adhesion between an inner insulation coating layer (hereinafter abbreviated as an inner layer) and a conductor in an insulated wire having two inner and outer insulation coating layers. It is about.

[0002]

2. Description of the Related Art In the case of an insulated wire in which a conductor is insulation-coated with a coating layer cross-linked with a cross-linking agent, it is coated by a chemical reaction of the cross-linking agent remaining in the coating layer during or after the cross-linking of the coating layer. The layer may cause adhesion with the conductor. The adhesion between the coating layer and the conductor occurs frequently in an insulated wire in which the conductor is a copper wire and the coating layer is cross-linked with sulfur, and especially when the coating layer contains butyl rubber, the coating layer becomes sticky. Therefore, it becomes remarkable.

When the conductor and the insulating coating layer are adhered to each other, it is difficult to strip the insulating coating layer from the conductor when the conductor is extended or connected, which greatly hinders automation of wire end processing.

In order to prevent the conductor and the insulating coating layer from adhering to each other, many methods have been proposed. As typical examples thereof, a method of adding a releasing agent to the material of the insulating coating layer, a method of applying a releasing agent to the conductor surface, a method of plating the conductor surface, or a releasing agent in the insulating coating material. This is an application example of the method of adding a mold agent, but when the insulation coating of the insulated wire consists of two inner and outer coating layers, by adding a release agent only to the inner layer insulation coating material, It has been proposed to suppress the deterioration of insulation properties and physical strength.

However, it is necessary to apply a high level of technology to uniformly apply the release agent to the surface of the conductor or to apply the plating to the surface of the conductor to a uniform thickness, and to release the release agent in the material of the insulating coating layer. With the method of adding the agent, if the adhesion between the conductor and the insulating coating layer is significant, it will not be effective unless a large amount of release agent is added.In this case, the insulation characteristics of the wire coating will deteriorate, and the physical strength will decrease. Failure of.

[0006]

DISCLOSURE OF THE INVENTION The present invention relates to an insulated electric wire having at least two inner and outer insulating coating layers, and has a decrease in the electrical characteristics such as the insulation characteristics of the insulating coating layer of the insulated wire and the physical characteristics such as mechanical strength. An object of the present invention is to provide an insulated electric wire in which the adhesion between the conductor and the inner layer is prevented without causing a decrease and without delamination between the inner and outer layers of the insulating coating layer.

[0007]

The above-mentioned object of the present invention has been achieved by an insulated wire which is prevented from adhering to the conductor of the present invention.

That is, the insulated wire described below.

(1) In an insulated wire having at least two inner and outer insulating coating layers, at least the inner insulating coating layer is crosslinked by an organic peroxide crosslinking method,
An insulated electric wire characterized in that adhesion between the inner insulating coating layer and a conductor is prevented.

(2) The material of the inner layer is EP rubber, butyl rubber, or butyl rubber / EP rubber blend type rubber, and the conductor is a copper wire conductor.
Insulated wire described in.

(3) The insulated wire according to the above (1) or (2), wherein the organic peroxide used for crosslinking the inner layer is dicumyl peroxide or ditertiarybutyl peroxydiisopropylbenzene. .

(4) In an insulated wire having at least two inner and outer insulating coating layers, the inner and outer two insulating coating layers are co-extruded and simultaneously cross-linked to delaminate the inner and outer two insulating coating layers. The insulated wire according to any one of (1) to (3), characterized in that it is prevented.

(5) In an insulated wire having at least two inner and outer insulation coating layers, the inner and outer two insulation coating layers are all crosslinked by an organic peroxide, and the outer insulation coating layer has a crosslink density. The insulated wire is characterized in that the adhesion between the inner insulating coating layer and the conductor is prevented by further increasing the crosslink density of the inner insulating coating layer.

(6) The insulated wire according to (5) above, wherein the material of the inner layer is EP rubber.

FIG. 1 shows an example of the insulated wire of the present invention. In FIG. 1, the surface of a conductor 1 is coated with an insulating material in the order of an inner insulating coating layer 2 and an outer insulating coating layer (hereinafter abbreviated as outer layer) 3 to form an insulated wire.

FIG. 1 supplements the description of the structure of the insulated wire of the present invention. However, the following supplementary description does not limit the present invention.

In the insulated wire of the present invention, the material of the conductor 1 is preferably copper or annealed copper. The constituent polymers of the inner layer 2 and the outer layer 3 are natural and synthetic rubbers such as natural rubber, styrene-butadiene rubber, styrene-isoprene rubber, ethylene-propylene (EP rubber) and butyl rubber, and blends thereof. EP of these
Rubber, butyl rubber or butyl rubber / EP rubber blend rubber is a preferred material.

Conventionally, the constituent polymers of the inner layer 2 and the outer layer 3 were cross-linked by a sulfur-based cross-linking agent and a vulcanization accelerator, but as described above, the chemical reaction of the cross-linking agent remaining in the coating layer, etc. As a result, the coating layer often caused adhesion with the conductor. Therefore, it is preferable to use at least a crosslinking agent for the inner layer 2 as an organic peroxide, and particularly to use dicumyl peroxide or ditertiarybutylperoxydiisopropylbenzene.

In the insulated wire of the present invention, the inner layer 2 and the outer layer 3 are put in a double extruder by charging respective materials such as polymer, filler, cross-linking agent and other additives from respective hoppers. It is preferable that the material for the inner and outer layers is simultaneously extruded and coated on the outer circumference of the conductor at the crosshead portion.

Not only in the case of two-layer coextrusion, but in general, when the inner layer 2 is made thicker, the properties such as the mechanical strength of the coating layer are deteriorated and the inner layer 2 is made thinner. However, it is difficult to extrude uniformly without forming broken points in the layer thickness.

[0021]

In the insulated wire having the inner and outer two-layer insulation coating layers, the main components such as the polymer and the filler constituting the inner layer and the outer layer are made the same to improve the affinity between the inner layer and the outer layer, Delamination between the two layers is prevented.

When the inner and outer two-layer insulation coating layers are co-extruded and simultaneously cross-linked to coat the electric wire, the cross-linking agents are intermigrated at the interfaces of the inner and outer two-layer insulation coating layers, so that delamination is prevented. To be done.

Furthermore, when an organic peroxide is used as a cross-linking agent for the inner layer, the cross-linking density of the inner layer is higher and the viscosity of the inner layer is lower than that when cross-linked with another cross-linking agent such as sulfur. It has the effect of preventing sticky adhesion with.

Furthermore, when an organic peroxide is used as a cross-linking agent for the inner and outer layers, increasing the cross-linking density of the inner layer has the effect of preventing tacky adhesion with the conductor.

[0025]

EXAMPLES The present invention will be specifically described below with reference to examples. However, the present invention is not limited to the following examples.

(Example 1) On an annealed copper wire having a diameter of 3.0 mm, an insulating coating having an inner layer thickness of 0.6 mm and an outer layer thickness of 3.35 mm was sequentially provided by two-layer coextrusion to give an outer diameter of 10.9.
mm insulation-coated electric wire was formed, and then steam crosslinking was performed by continuing the process. The crosslinking conditions are vapor pressure 18 kgf / cm ² (206
C.) for 3 minutes.

Table 1 shows the compounding recipe of the inner layer and the outer layer.

[0028]

[Table 1]

A butyl rubber / EP rubber blend rubber is used as a raw material, and a butyl rubber / EP rubber blend rubber is similarly used as a raw material between the outer layer formed by crosslinking with sulfur and a vulcanization accelerator and the conductor. By providing the inner layer formed by cross-linking with a conductive peroxide cross-linking agent, the inner layer serves as an adhesion prevention layer, which has the effect of preventing the insulation coating layer from adhering to the conductor.

Example 2 On an annealed copper wire having a diameter of 3.0 mm, the same thickness and the same cross-linking conditions as in Example 1 were used and Table 2
An inner layer and an outer layer of the compounding recipe shown in 1) were provided.

[0031]

[Table 2]

In the example shown in Example 2, as in the example shown in Example 1, by providing an inner layer formed by crosslinking with an organic peroxide cross-linking agent, the inner layer becomes an anti-adhesion layer,
This is an example in which the adhesion of the insulating coating layer to the conductor is prevented.

(Example 3) On an annealed copper wire having a diameter of 3.0 mm, the same thickness and the same cross-linking conditions as in Example 1 were used and Table 3
An inner layer and an outer layer of the compounding recipe shown in 1) were provided.

[0034]

[Table 3]

In the example shown in Example 3, an organic peroxide is used as a cross-linking agent for both the inner and outer layers, but adhesion of the insulating coating layer to the conductor is prevented by increasing the cross-linking density of the inner layer.

(Comparative Examples 1 to 3) An insulating coating is provided by extrusion on an annealed copper wire having a diameter of 3.0 mm to obtain an outer diameter of 10.9 mm.
The insulation-coated electric wire of No. 1 was molded, and then the steam-crosslinking was performed by continuing the process. The crosslinking conditions are vapor pressure 18 kgf / cm ² (206
C.) for 3 minutes.

Table 4 shows the compounding formulation of the insulating coating.

[0038]

[Table 4]

The formulation of the insulating coating of Comparative Example 1 was compared with the formulation of the outer insulating coating of Example 1, and the formulation of the insulating coating of Comparative Example 2 was compared with the formulation of the outer insulating coating of Example 2. The formulation of the insulating coating of Example 3 is the same as the formulation of the outer insulating coating of Example 3, respectively.

(Conductor Extraction Test and Results) Examples 1 to 1
3 and the electric wires prepared in Comparative Examples 1 to 3 at 80 ° C.
After heat treatment for a time, each was cut into a length of 35 mm to prepare a test electric wire.

A conductor pull-out test was performed on each test electric wire at a pull-out speed of 200 mm / min.

The test results are shown in Table 5.

[0043]

[Table 5]

The electric wires of the present invention of Examples 1 to 3 are the same as Comparative Example 1.
The pull-out strength is lower than the electric wires of Nos. 3 to 3, and the amount of rubber attached to the conductor is small.

[0045]

As described above, the obstacle to the automation of the wire end processing due to the occurrence of the conductor adhesion of the insulating layer in the conventional insulated wire is such that the inner layer formed by crosslinking with the organic peroxide cross-linking agent is provided. By providing the insulated wire of the present invention, the following important effects can be obtained.

That is, the conductor adhesion of the insulating layer was prevented by providing the inner layer formed by crosslinking with the organic peroxide crosslinking agent as the lower layer of the insulating layer in the conventional insulated wire.

The inner and outer two layers are used as the insulating coating layers, and the two inner and outer insulating coating layers are co-extruded and simultaneously crosslinked to prevent delamination of the inner and outer two layers.

Even when the insulating layer is composed of butyl rubber as a constituent polymer and the adhesion of the insulating layer to the conductor is remarkable,
It was possible to prevent the conductor from adhering to the insulating layer by forming the insulating coating layer into two layers, the inner layer and the outer layer, and using the butyl rubber / EP rubber blend rubber of the inner layer as a material and crosslinking with an organic peroxide crosslinking agent.

In the case where the insulating coating layer has two layers of inner and outer layers and the crosslinking agent of the two layers of inner and outer layers is an organic peroxide crosslinking agent,
By increasing the crosslink density of the inner layer, it was possible to prevent the conductor from adhering to the insulating layer.

[Brief description of drawings]

FIG. 1 is an electric wire axial sectional view of an example of an insulated electric wire in which adhesion with a conductor of the present invention is prevented.

[Explanation of symbols] 1 conductor 2 inner insulating coating layer (inner layer) 3 outer insulating coating layer (outer layer)

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Kenichi Furusawa 5-1-1 Hidakacho, Hitachi City, Hitachi, Ibaraki Prefecture Hidaka Plant, Hitachi Cable, Ltd. (72) Ko Makino, 5 Hidakacho, Hitachi City, Ibaraki Prefecture 1-1-1 Hitachi Cable Co., Ltd. Hidaka Factory

Claims (6)

[Claims] 1. An insulated electric wire having at least two inner and outer insulating coating layers, wherein at least the inner insulating coating layer is crosslinked by an organic peroxide so that the inner insulating coating layer and the conductor are bonded to each other. Insulated wire characterized by being prevented. 2. The insulated wire according to claim 1, wherein the material of the inner insulating coating layer is EP rubber, butyl rubber, or butyl rubber / EP rubber blend rubber, and the conductor is a copper wire conductor. 3. The insulation according to claim 1, wherein the organic peroxide used for crosslinking the inner insulating coating layer is dicumyl peroxide or ditertiarybutylperoxydiisopropylbenzene. Electrical wire. 4. An insulated wire having at least two inner and outer insulating coating layers, wherein the inner and outer two insulating coating layers are coextruded and simultaneously crosslinked to prevent delamination of the two inner and outer insulating coating layers. The insulated wire according to any one of claims 1 to 3, wherein 5. In an insulated wire having at least two inner and outer insulating coating layers, both of the inner and outer insulating coating layers are crosslinked by an organic peroxide, and the crosslink density of the outer insulating coating layer is higher than that of the outer insulating coating layer. An insulated wire, wherein adhesion between the inner insulating coating layer and the conductor is prevented by increasing the crosslink density of the inner insulating coating layer. 6. The insulated wire according to claim 5, wherein the material of the inner insulating coating layer is EP rubber.