JPS5951689B2 - Manufacturing method of insulated wire - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing an insulated wire having extremely excellent long-term stability in terms of mechanical properties and electrical properties, and particularly relates to a method for producing an insulated wire having extremely excellent long-term stability in terms of mechanical properties and electrical properties. The present invention relates to a method of manufacturing an insulated wire having a vulcanized ethylene-acrylic elastomer applied thereon.

In recent years, power distribution systems have become more lightweight and compact, and along with this, it is desirable for insulated wires to have as thin a wall insulation as possible to ensure long-term stability in terms of mechanical and electrical properties. It is rare.

Research conducted by the present inventors in order to meet the above-mentioned demands in this field. According to research, when an unvulcanized ethylene-acrylic elastomer is coated on an ethylene-propylene rubber insulation layer by extrusion to a specific thickness and then vulcanized, an insulated wire with unexpectedly excellent long-term stability can be produced. We obtained new knowledge that it can be manufactured. The present invention provides a completed method for manufacturing an insulated wire based on the above-mentioned new findings, and includes a method for manufacturing an insulated wire, in which unvulcanized ethylene -0 acrylic elastomer
．． It is characterized by extrusion coating to a thickness of 3 to 0.7 mm and then vulcanization.

In order to achieve the above object of the present invention, a combination of insulating coating layers made of a specific rubber type, including an ethylene propylene rubber insulating layer as a lower layer and an ethylene-acrylic elastomer coating layer as an upper layer, and the above-mentioned upper layer It is particularly important that the coating layer is coated with a specific thickness of J0.3 to 0.7 mm by extrusion processing, and as far as the extensive research conducted by the present inventors is concerned, the above conditions are satisfied. Only in this case can an insulated wire with very remarkable long-term stability, which will be described later, be produced with thin insulation. In the present invention, ethylene-propylene-diene terpolymer (EPDM) and ethylene-propylene copolymer (EPM) are used as the ethylene-propylene-based insulating rubber used as the lower layer insulation material, and ethylene propylene-based insulation rubber used as the upper layer coating material. - As the acrylic elastomer, a terpolymer consisting of ethylene-methyl acrylate and a carboxyl group-containing third monomer is used. If the upper coating layer is applied thinner than 0.3 mm, the mechanical properties of the resulting insulated wire will deteriorate.
On the other hand, if the coating is thicker than 0.7 mm, the performance will be significantly poorer in terms of both mechanical and electrical properties.

Therefore, the thickness of the upper coating layer is 0.3 mm to 0.3 mm.
7 mm, preferably 0.3 mm to 0.5 mm. In the present invention, the lower ethylene/propylene rubber insulating layer may be vulcanized in advance, or the ethylene/acrylic elastomer of the upper layer coating material may be extrusion coated on it while it is in an unvulcanized state, or The lower insulating material and the upper covering material may be extrusion coated at the same time, and both the upper and lower layers may be vulcanized at the same time.

The preferred thickness of the lower ethylene/propylene rubber insulating layer is 1.0 to 6.0, particularly 1.0 to 4.0.
If it is made into a zero-use type, even better performance can be obtained in terms of mechanical properties. In the present invention, fillers, carbon bracing, anti-aging materials, etc. may be appropriately added to the insulation coating materials of the upper and lower layers.

Here, an example of a method for manufacturing an insulated wire according to the present invention will be explained.

That is, a conductor with a conductor cross-sectional area of 14 mit was coated with an ethylene propylene insulator to a thickness of 3 mm by extrusion, and an ethylene-aryl elastomer (VAMAC manufactured by Dupont...
...100, lubricant ...3 parts, anti-aging agent.
...2 parts, methylene diamine ...1.2
5 parts, diphenylguanidine...2 parts, talc...100 parts, power bomb black...
5 parts, plasticizer...10 parts) to a thickness of 0.5 mm.

Next, steam vulcanization was performed at a temperature of 200° C. to obtain an insulated wire as shown in an enlarged view in FIG. In the figure, 1 is a conductor, 2 is an ethylene propylene rubber insulating layer, and 3 is an ethylene-acrylic elastomer coating layer. Next, a performance comparison between the insulated wire obtained by the present invention and a conventional insulated wire of this type will be explained using Experimental Example 1 below. Experimental example 1. Experimental samples include vulcanized ethylene/propylene rubber insulated wire cable (sample-1) and vulcanized ethylene/propylene rubber insulated epichlorohydrin rubber coated cable (sample-2)
, manufactured vulcanized ethylene/propylene insulated ethylene/acrylate elastomer coated cable (Sample-3) (
All of the above cables have a conductor cross-sectional area of 14 mit, are for 600 V, and have an upper coating layer thickness of 0.5 mm.

)did. A performance test was conducted on the above sample under the following conditions, and the results were as shown in Table 1. In Table 1 above, the tensile strength is determined by suspending a wire sample with both ends sealed with araldite in a gear type aging tester at 160°C, heating it for the time listed in Table 1, taking it out, and testing the rubber from the insulation coating layer of the wire sample. Create a piece and JISC3OO4
A tensile test was carried out according to page 19.

In addition, the AC breakdown voltage is determined by bending a 75cm long wire into a U shape.
The time listed in Table 1 in the gear type aging tester, 160
After heating at .degree. C., the sample was taken out and its breakdown voltage at 60 C/S AC was measured using the step-up method at 5 kg/10 seconds. As shown in Table 1 above, the insulated wire obtained by the present invention has excellent long-term electrical performance and
Exhibits mechanical stability.

Experimental example 2. As an experimental sample, a vulcanized ethylene/propylene rubber insulated Evitalolohydrin rubber coated electric wire (Sample 1 3: Conductor cross-sectional area 2
2m71, for 600V, epitalohydrin rubber coating thickness 0.5mm) and vulcanized ethylene/propylene insulated ethylene-acrylic elastomer coated electric wire (Sample-6:
Conductor cross-sectional area: 22 md, 600 V, ethylene-acrylic elastomer coating layer thickness: 0.5 mm) were manufactured, and these samples were used for 3 months under the following environment.

In other words, the cable has an ambient temperature of 140°C to 150°C.
It is exposed to high temperatures, is occasionally splashed with oil, and is constantly subjected to bending, vibration, and friction. Table 2 shows the degree of deterioration when used under such severe conditions. As is clear from the above experiments, the insulated wire obtained according to the present invention shows extremely less deterioration mechanically, electrically, and chemically than conventional wires of this type.

The present invention is a method for manufacturing an insulated wire as described above,
It is possible to easily provide an insulated wire that is electrically, mechanically, and chemically stable for a long period of time.

In addition, the insulated wire obtained by the present invention does not deteriorate due to heat, for example when heated at temperatures of 100°C to 16°C near an electric furnace.
It is possible to install the device in a high temperature atmosphere of 0°C for a long time.
Furthermore, even when immersed in oil, the insulating layer does not swell, and its mechanical and electrical functions do not deteriorate. Further, by using a flame retardant material as the upper coating layer, the electric wire itself can be made flame retardant.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing an example of an insulated wire obtained by the present invention. In the figure, 1 is a conductor, 2 is an ethylene propylene rubber insulating layer, and 3 is an ethylene-acrylic elastomer coating layer.

Claims (1)

[Claims] Extrusion coating an unvulcanized ethylene-acrylic elastomer to a thickness of 0.3 to 0.7 mm on the vulcanized or unvulcanized ethylene-propylene rubber insulating layer coated on the conductor,
A method for manufacturing an insulated wire, which comprises then vulcanizing.