JP2000231835A - Two-layer bridged insulating electric wire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To significantly improve productivity and quality by coating a flame- resistant bridged insulating layer on a lead wire and by coating a non-powder- scattering insulating layer on the flame-resistant bridged insulating layer. SOLUTION: As for a flame-resistant bridged insulating layer, a flame- resistant bridged polyolefin is preferable. On a copper wire (conductor 1) having an outer diameter of 2.0 mm, a flame-resistant bridged polyethylene composition comprised of 100 pts.wt. of a polyethylene mixed with 80 pts.wt. of a halogenic flame-resistant agent and 0.5 pts.wt. of a peroxide as a crosslinking agent is extruded and coated in a thickness of 0.35 mm. On a flame-resistant bridged polyethylene layer 2, a non-powder-scattering flame-resistant bridged polyethylene composition comprised of 100 pts.wt. of the polyethylene mixed with 5 pts.wt. of the halogenic flame-resistant agent and 0.5 pts.wt. of the peroxide as a crosslinking agent is extruded and coated in a thickness of 0.05 mm (powder-unflying flame-resistant bridged polyethylene composition layer 4) and passed through an electron bridging device to obtain a two-layer bridged insulating electric wire.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a double-layer insulated wire.

[0002]

2. Description of the Related Art In view of fire safety, demand for flame-retardant insulated wires has been increasing.

[0003] Crosslinked polyethylene insulated wires have electrical properties,
It is widely used because of its excellent mechanical, chemical and thermal properties, and its relatively low cost.

[0004] However, the crosslinked polyethylene insulated wire is essentially made of a flammable hydrocarbon-based resin, and thus has a disadvantage in that the fire resistance is inferior.

[0005] Therefore, flame-retardant crosslinked polyethylene insulated wires having improved flame retardancy have been widely used.

In order to manufacture a flame-retardant cross-linked polyethylene insulated wire, first, a flame-retardant polyethylene composition is prepared by mixing a cross-linking agent, a powder flame retardant, etc. with polyethylene, and then the flame-retardant polyethylene composition is introduced. The non-crosslinked flame-retardant polyethylene composition-coated wire is extruded and coated on the wire, and finally the non-crosslinked flame-retardant polyethylene composition-coated wire is crosslinked by passing through a crosslinking device.

Here, examples of the powdered flame retardant include a halogenated flame retardant, antimony trioxide, red phosphorus, and a non-halogen metal hydroxide.

[0008]

By the way, it is known that polyethylene has a large molecular weight and a large molecular cohesion, and as a result, its compatibility with other resins and powders is poor.

[0009] For this reason, the uncrosslinked flame-retardant polyethylene composition-coated electric wire has a property that the powdered flame retardant easily jumps out because the polyethylene is not crosslinked. For example, an uncrosslinked flame-retardant polyethylene composition is extruded onto a conductive wire by an extruder to form an uncrosslinked flame-retardant polyethylene composition-coated wire, and then the obtained uncrosslinked flame-retardant polyethylene composition is obtained. When winding the covered electric wire with a winding device via a guide roll, a capstan, or the like, the powder flame retardant is scattered from the uncrosslinked flame-retardant polyethylene composition-coated electric wire to the roll, the winding device, or the like, Or adhere. Further, when the uncrosslinked flame-retardant polyethylene composition-coated electric wire is passed through a crosslinking device, for example, an electron beam crosslinking device, the powdered flame retardant is scattered or adhered to a guide roll, a capstan, a crosslinking device, and the like. In particular, when passing through an electron beam cross-linking device at high temperature, high pressure, and high speed, a tremendous amount of powdered flame retardant scatters, adheres, or aggregates on guide rolls, capstans, cross-linking devices, and the like.

The scattered, adhered, or agglomerated powdered flame retardant deteriorates the appearance and properties of the flame-retardant cross-linked polyethylene insulated wire. Further, the powdered flame retardant that has been scattered, adhered or agglomerated needs to be removed cleanly after completion of the crosslinking step. However, such a removal operation is troublesome, and as a result, the productivity is significantly reduced.

The present invention has been made in view of such a point, and an object of the present invention is to solve the above-mentioned disadvantages of the prior art, and to provide an external appearance of a flame-retardant cross-linked polyethylene insulated wire,
An object of the present invention is to provide a double-layer cross-linked insulated wire capable of significantly improving productivity without lowering various characteristics.

[0012]

The gist of the present invention is that a conductive wire is coated with a flame-retardant cross-linked insulating layer, and a non-powder-scattering insulating layer is coated on the flame-retardant cross-linked insulating layer. A two-layer crosslinked insulated wire characterized by comprising:

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment of the double-layer crosslinked insulated wire of the present invention will be described.

In the present invention, the flame-retardant crosslinked insulating layer includes
It is preferably a flame-retardant crosslinked polyolefin. Here, the flame-retardant crosslinked polyolefin is obtained by crosslinking a flame-retardant polyolefin resin composition obtained by blending a polyolefin with a powdered flame retardant and a crosslinking agent.

In the present invention, the non-powderable insulating layer is preferably made of a vinyl chloride resin admixture. This is because the vinyl chloride resin admixture is a halogen-based resin having excellent flame retardancy, and has excellent compatibility with other compounding agents and resins.

In the present invention, the non-powderable insulating layer is preferably a non-powderable flame-retardant polyolefin.

Here, the non-powderable flame-retardant polyolefin is one in which the amount of the powdered flame retardant blended into the polyolefin is reduced to an amount that can prevent pop-out. For example, a flame-retardant crosslinked polyolefin is polyolefin 100
Whereas 20 to 200 parts by weight of a powder flame retardant is blended in parts by weight, the non-powderable flame-retardant polyolefin is 100 parts by weight of polyolefin and 0.5 to 0.5 parts by weight of a powder flame retardant.
15 parts by weight were blended.

In the production of the double-layer crosslinked insulated wire of the present invention, the work of extruding and coating the flame-retardant crosslinked insulating layer directly above the conductor and the work of extruding and coating the non-powderable insulating layer are performed in two steps, or in one step. It may be performed in a process.

In one step, the main extruder and the sub-extruder are arranged side by side, and the main extruder extrudes and coats the flame-retardant crosslinked insulating layer, and the sub-extruder extrudes and coats the non-powderable insulating layer continuously. Performed in one step. In addition, two extrusion heads can be provided in one Oshida machine, and the extrusion coating operation of the flame-retardant cross-linked insulating layer and the extrusion operation of the non-powder-scattering insulating layer can be performed simultaneously.

[0020]

Next, examples and comparative examples of the double-layer crosslinked insulated wire of the present invention will be described.

(Example 1) On a copper wire having an outer diameter of 2.0 mm,
A flame-retardant cross-linked polyethylene composition obtained by blending 80 parts by weight of a halogen-based flame retardant (dechlorane) as a powder flame retardant and 0.5 parts by weight of dicymil peroxide as a cross-linking agent in 100 parts by weight of polyethylene is 0.35 mm thick. And extruded.

Next, on the flame-retardant cross-linked polyethylene insulating layer, a vinyl chloride resin mixture for electrical insulation was extruded to a thickness of 0.05 mm to cover and then passed through an electron beam cross-linking apparatus. Was obtained.

FIG. 1 is a cross-sectional view of the double-layer crosslinked insulated wire of Example 1 thus obtained.

In FIG. 1, 1 is a conducting wire, 2 is a cross-linked polyethylene insulating layer, and 3 is a vinyl chloride resin admixture layer.

(Example 2) On a copper wire having an outer diameter of 2.0 mm,
A flame-retardant cross-linked polyethylene composition obtained by blending 80 parts by weight of a halogen-based flame retardant (dechlorane) as a powder flame retardant and 0.5 parts by weight of dicymil peroxide as a cross-linking agent in 100 parts by weight of polyethylene is 0.35 mm thick. And extruded.

Next, on the flame-retardant crosslinked polyethylene insulating layer, 5 parts by weight of a halogen-based flame retardant (dechlorane) as a powdered flame retardant and 0.5 parts by weight of dicumyl peroxide as a crosslinking agent were added to 100 parts by weight of polyethylene. Was extruded to a thickness of 0.05 mm to cover the non-powderable flame-retardant crosslinked polyethylene composition, and then passed through an electron beam crosslinking device to obtain a double-layer crosslinked insulated wire of Example 2.

FIG. 2 is a sectional view of the double-layer crosslinked insulated wire of Example 2 obtained in this manner.

In FIG. 2, reference numeral 1 denotes a conductive wire, 2 denotes a crosslinked polyethylene insulating layer, and 4 denotes a non-powderable flame-retardant crosslinked polyethylene composition layer.

(Comparative Example 1) On a copper wire having an outer diameter of 2.0 mm,
A flame-retardant cross-linked polyethylene composition comprising 100 parts by weight of polyethylene and 80 parts by weight of a halogen-based flame retardant (dechlorane) as a powder flame retardant and 0.5 parts by weight of dicumyl peroxide as a cross-linking agent is 0.40 mm thick. Extruded and coated
Then, by passing through an electron beam crosslinking device, a double-layered insulated wire of Comparative Example 1 was obtained.

(Evaluation of Characteristics) The evaluation of characteristics was performed by the following method. Evaluation was made on the appearance of the insulated wire.

Table 1 shows the results of these evaluations.

[0032]

[Table 1]

As can be seen from Table 1, in the crosslinked insulated wire of Comparative Example 1, the powdered flame retardant was scattered to the guide rolls, capstans, crosslinkers and the like in the electron beam crosslinking step, and the crosslinked insulated wire was obtained by crosslinking. The appearance was bad. In addition,
Although not shown in Table 1, cleaning of the scattered powder flame retardant,
Removal took many man-hours.

On the other hand, in the double-layer crosslinked insulated wires of Examples 1 and 2, there is no scattering of the powdery flame retardant into the guide rolls, capstans, crosslinkers, etc. in the electron beam crosslinking step, and the crosslinked wires are crosslinked. The appearance of the obtained crosslinked insulated wire was good. For this reason, Example 1 and Example 2
The double-layer cross-linked insulated wire was able to significantly improve productivity and quality.

[0035]

The double-layer crosslinked insulated wire of the present invention has a large amount of powdered flame retardant compounded even when an uncrosslinked flame-retardant polyethylene composition-coated wire is passed through guide rolls, capstans, crosslinkers and the like. Scattering can be effectively suppressed, and as a result, the productivity and quality of the cross-linked insulated electric wire can be remarkably increased, which is industrially useful.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a double-layer crosslinked insulated wire according to a first embodiment of the present invention.

FIG. 2 is a sectional view of a double-layer crosslinked insulated wire according to a second embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Conductor 2 Crosslinked polyethylene insulating layer 3 Vinyl chloride resin admixture layer 4 Non-powderable flame-retardant crosslinked polyethylene composition layer

Claims (4)

[Claims] 1. A flame-retardant cross-linked insulating layer is coated on a conductive wire,
A two-layer crosslinked insulated wire, characterized in that a non-powderable insulating layer is coated on an upper layer of the flame-retardant crosslinked insulating layer. 2. The double-layer cross-linked insulated wire according to claim 1, wherein the flame-retardant cross-linked insulating layer is a flame-retardant cross-linked polyolefin. 3. The double-layer crosslinked insulated wire according to claim 1, wherein the non-powderable insulating layer is made of a vinyl chloride resin admixture. 4. The double-layer crosslinked insulated wire according to claim 1, wherein the non-powderable insulating layer is a non-powderable flame-retardant crosslinked polyolefin.