JPS59219882A - Method of forming rubber and plastic cable connector - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for forming intermediate or terminal connections of rubber-plastic cables.

As is well known, in the connection of rubber/plastic cables, in order to electrically insulate and reinforce the connection, an internal semiconductive layer is formed on the cable conductor connection, and then an insulating reinforcing layer is provided on top of that. .

Conventionally, in order to form an insulating reinforcing layer, as shown in the drawing, a cable conductor connection part 1 provided with an internal semiconducting layer 2 is covered with a leek split mold, and the mold is filled with a resin extruder (or injection machine) 11. After connecting the mold and heating the mold to a predetermined temperature, a crosslinkable resin is filled into the mold from a resin extruder (or injection machine) 11, and then the mold is heated to raise the temperature to fill the crosslinkable resin. The reinforcing insulating layer 5 was formed by crosslinking and then cooling the mold.

However, in the conventional method of forming connections, during the crosslinking process in which the mold is heated to raise the temperature to crosslink the crosslinkable resin, the crosslinking agent, such as organic peroxide, contained in the crosslinkable resin is thermally decomposed and gases out into methane gas. etc., and if the pressure inside the mold is insufficient, the gas foams in the reinforcing insulating layer during the crosslinking process, the subsequent mold cooling process, or both processes, forming voids, and corona occurs when AC current is applied. There was a problem in that discharge occurred and electrical characteristics deteriorated.

The present invention was made in view of the above-mentioned problems, and is made of rubber that prevents foaming within the reinforcing insulating layer and does not reduce electrical properties.
This provides a method for molding a plastic cable connection part, during the crosslinking process in which the mold is heated to raise the temperature to crosslink the crosslinkable resin, which is a process after filling the mold with a crosslinkable resin, or during the crosslinking process in which the mold is heated to raise the temperature to crosslink the crosslinkable resin. It is characterized by continuing to inject resin into the mold during the cooling step or both steps to maintain the pressure inside the mold at a high pressure.

Hereinafter, one embodiment of the present invention will be described with reference to the drawings.
Both cable conductors to be connected are connected with a compression sleeve, and an internal semiconducting layer 2 is provided thereon by, for example, a semiconducting shrink tube to form a cable conductor connection part 1, and the connection part 1 is covered with gold. The method of covering the mold with a resin extruder (or injection machine), heating the mold to a predetermined temperature, and then filling the mold with crosslinking resin is the same as the conventional method. However, in the present invention, the mold cavity is cooled during the crosslinking process in which the mold cavity is heated to raise the temperature to crosslink the crosslinkable resin, which is a process after filling the mold cavity with the crosslinkable resin. An extruder (or injection machine) 4 is installed in the mold during the cooling process or both processes.
Continue to inject more resin.

In this way, by continuing to inject resin into the mold during the crosslinking process, cooling process, or both processes, the pressure inside the mold can be kept high, and voids caused by decomposition gas of the crosslinking agent generated during the crosslinking process can be prevented. can be effectively prevented from occurring within the reinforcing insulating layer.

The type of resin that is continuously injected into the mold is not limited to the same resin as the crosslinkable resin forming the reinforcing insulating layer, but may be a different resin, and the type of resin is not particularly limited.

Next, to explain a specific example of the present invention, the end of a 66IQ+ cross-linked polyethylene insulated cable is shaved into a pencil shape, the conductor is connected with a compression sleeve, and a semiconductive tape is wrapped and heat fused on top of the end to form an inner half. After forming the conductive layer, a two-split mold was placed over the conductor connection portion, and a 120 mm
HFDJ1120 manufactured by Nippon Unicar is placed in a mold heated to ℃.
1K (crosslinkable resin) was extruded and injected at a resin temperature of 120°C,
After confirming that the mold was filled with resin, the mold was heated and cooled by the method shown in the table below to form a reinforcing insulating layer at the connection part. Applying a voltage of 170 KVT to the reinforcing insulating layer for 3 hours,
Thereafter, the voltage was increased to 15 KV in steps of 30 minutes, and an AC breakdown test was conducted on the reinforcing insulating layer. The results are shown in the table below.

As described above, according to the method for molding a rubber/plastic cable connection part according to the present invention, resin is continuously injected into the mold during the crosslinking process, the cooling process, or both processes to increase the pressure inside the mold. Therefore, it is possible to obtain a connection (intermediate connection or terminal connection) with good electrical properties without creating voids in the reinforcing insulating layer.

[Brief explanation of drawings]

The drawing is an explanatory view showing one embodiment of a method of molding a rubber/plastic cable connection part. 1 is a conductor connection part, 2 is an internal semiconductive layer, 5 is a mold, 4 is an extruder, 5 is a reinforcing insulating layer

Claims (1)

[Claims] A mold is placed over the cable conductor connection part with an internal semiconductive layer on the outer circumferential surface, and after heating the mold to a predetermined temperature, the mold is filled with a crosslinking resin, and then the mold is heated and raised. In a method for forming a rubber/plastic cable connection part in which a crosslinkable resin is crosslinked by heating and then a mold is cooled to form a reinforcing insulating layer, the crosslinkable resin is crosslinked by heating the mold to raise the temperature. A method of molding a rubber/plastic cable connection part characterized by continuously injecting resin into the mold during the crosslinking process, the cooling process of cooling the mold, or both processes to maintain the pressure inside the mold at a high pressure. .