JPS6331412A - Manufacture of reinforced insulation of plastic insulated cable - Google Patents

Abstract

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

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for manufacturing an insulation reinforcing portion of a plastic insulated cable, and in particular, it involves forming an insulating synthetic resin containing a crosslinking agent into a predetermined shape at a location where insulation reinforcement is to be performed. It can be used in cases where the method is carried out by molding, then providing a conductive layer on the periphery, and then heating the entire structure to crosslink the synthetic resin and bonding and integrating the two.

[Prior Art] The conventional manufacturing method of this type of insulation reinforcing part will be explained using FIG. 1, taking the case of a straight connection part as an example. First, each insulator 2.2' of a cable 1.1' to be connected is The conductor 3.3' is removed at the end to expose the conductor 3.3', and then these conductors 3, 3' are connected with a predetermined conductor connection pipe 4, and if necessary, these conductors 3.3' and the conductor connection pipe are connected. An internal conductive layer 5 is provided on four circumferences using a crosslinked conductive heat-shrinkable tube, then an insulating synthetic resin 6 containing a crosslinking agent is molded into a predetermined shape on these circumferences, and then on this circumference also External conductive layer 7 using cross-linked conductive heat-shrinkable tubing
, and then heat the entire structure to crosslink the synthetic resin 6 and bond and integrate the synthetic resin 6 and the conductive layers 5 and 7.

[Problems to be Solved by the Invention]However, in the conventional method as described above, when the temperature is raised for crosslinking treatment, the crosslinking agent in the synthetic resin 6 becomes conductive N5.7 as shown in FIG. (conductive layer 5.7)
This occurs because it has already been crosslinked and no longer contains any crosslinking agent. ), the concentration of the crosslinking agent in the synthetic resin 6 near the interface is about half of that in other parts. For this reason, the degree of crosslinking of the synthetic resin 6 near the interface decreases to about half that of other parts, and depending on the amount of crosslinking agent, the strength of the bond between the synthetic resin 6 and the conductive layers 5 and 7 may decrease. This may lead to a decrease in the electrical strength of this part.

In particular, in the rising portion of the tip of the stress cone (both end portions of the synthetic resin 6), the volume of the synthetic resin 6 is small and the crosslinking agent diffuses into both the conductive layer 7 and the cable insulator 2.2', so the conductive The concentration of the crosslinking agent near the interface with layer 7 is further reduced, and there is a concern that the performance will deteriorate.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method for manufacturing a plastic insulated cable insulation reinforcing part that overcomes the drawbacks of the prior art described above and is electrically superior to -N.

[Means for Solving the Problems] The gist of the present invention is to provide a conductive layer containing a crosslinking agent on the periphery of an insulating synthetic resin containing a crosslinking agent molded into a predetermined shape, and then heating the entire layer. The objective is to crosslink the synthetic resin and bind and integrate both the synthetic resin and the conductive layer.

The amount of crosslinking agent in the conductive layer is not particularly limited, but it is preferably about the same as that in the insulating synthetic resin.

[Function] By mixing the crosslinking agent into the conductive layer provided on the periphery of the crosslinking agent-containing insulating synthetic resin molded into a predetermined shape as described above, the crosslinking agent in the synthetic resin and the conductive layer can be mixed. This prevents the crosslinking agent in the synthetic resin from diffusing into the conductive layer during crosslinking treatment.

[Example] Next, the present invention will be described in detail with reference to the first example, but it goes without saying that the present invention is not to be construed as limited by the present example. For example, in this example, a case will be explained in which an insulation reinforcement part of a straight connection part of a cross-linked polyethylene insulated cable (hereinafter referred to as "C■ cable") is manufactured, but the insulation reinforcement part of other plastic insulated cables will be explained. In the case of manufacturing, the present invention can also be utilized when manufacturing insulation reinforcement parts such as branch connection parts, terminal parts, device direct connection parts, and repair parts of cables. Furthermore, in this example, a method using a mold is used to mold the insulating synthetic resin containing a crosslinking agent into a predetermined shape. It is also possible to mold the resin into a predetermined shape.

Now, to explain the present invention in detail, first, the respective insulators 2.2' of the Cv cables 1, 1' to be connected are removed at the ends to expose the conductors 3.3', and then these conductors 3.3' are removed. 3' are connected to each other by a predetermined conductor connecting tube 4, and if necessary, an internal conductive layer 5 containing a crosslinking agent is provided on the periphery of these conductors 3, 3' and the conductor connecting tube 4. More specifically,
This cross-linking agent-containing internal conductive layer 5 is formed by impregnating a conductive tube that has been cross-linked and expanded to a predetermined size again with a cross-linking agent, and shrinking it by heating to an extent that the cross-linking reaction does not proceed. be done. Incidentally, the conductive tube is inserted around the conductor 3.3' and the conductor connecting tube 4.
Before connecting 3' to each other, insert it over the circumference of one of the C■ cables 1.1', and after connecting conductors 3 and 3', connect it to conductor 3.3' and the conductor connecting pipe. This is done by moving up four laps.

Next, a mold of a predetermined shape (not shown) is formed on these circumferences.
At the same time, softened insulating polyethylene containing a crosslinking agent is injected into the mold to form an insulating polyethylene 6 containing a crosslinking agent into a predetermined shape.

Next, an external conductive layer 7 containing a cross-linking agent formed in the same manner as the internal conductive layer 5 containing a cross-linking agent is provided on this same layer, and then the whole is heated to cross-link the insulating polyethylene 6 and to form an insulating layer. The polyethylene 6 and the inner and outer conductive layers 5.7 are bonded and integrated.

[Effects] According to this embodiment carried out in this manner, the conductive layer 7 provided on the periphery of the crosslinking agent-containing insulating polyethylene 6 molded into a predetermined shape (and the internal conductive layer 5 provided as necessary) ) By mixing the crosslinking agent in the insulating polyethylene 6 and the crosslinking agent in the inner and outer conductive layers 5.7, the insulating polyethylene 6 is balanced with the crosslinking agent in the inner and outer conductive layers 5. Diffusion of the crosslinking agent into the inner and outer conductive layers 5.7 can be effectively prevented.

As described above, the present invention can effectively achieve the above-mentioned object, and it can be said that its industrial value is extremely large.

[Brief explanation of drawings]

FIG. 1 is a common diagram for explaining an embodiment of the method for manufacturing an insulation reinforcing portion of a plastic insulated cable according to the present invention and a conventional manufacturing method of this type. FIG. 2 is an explanatory diagram of the diffusion state of the crosslinking agent near the interface between the crosslinking agent-containing insulating synthetic resin molded into a predetermined shape and the conductive layer formed in contact therewith. 1.1'; CV cable (plastic insulated cable), 2.2'; insulator, 3.3'; conductor, 4; conductor connecting tube, 5; internal conductive layer containing crosslinking agent (crosslinked internal conductive layer), 6; Insulating polyethylene containing a crosslinking agent (insulating synthetic resin containing a crosslinking agent); 7; Outer conductive layer containing a crosslinking agent (crosslinked outer conductive layer). Agent Patent Attorney Usui 1) Toshiyuki Figure 1 1.1'; CV cable (plastic insulated cable), 2.2'; Insulator, 3.3'; Conductor, 4; Conductor connecting pipe, 5; Cross-linking agent 6; Insulating polyethylene containing crosslinking agent (insulating synthetic resin containing crosslinking agent); 7; Outer conductive layer containing crosslinking agent (crosslinked outer conductive layer)

Claims (6)

[Claims] (1) An insulating synthetic resin containing a cross-linking agent is molded into a predetermined shape at the part of the plastic insulated cable where the insulation is to be reinforced, and then a conductive layer containing a cross-linking agent is provided on the circumference, and then the whole is heated. 1. A method for producing an insulation reinforcing section of a plastic insulated cable, which comprises crosslinking a synthetic resin and bonding and integrating both the synthetic resin and a conductive layer. (2) A mold of a predetermined shape is placed over the part of the plastic insulated cable where the insulation is to be reinforced, and then a softened insulating synthetic resin containing a crosslinking agent is injected into the mold and the synthetic resin is molded into the predetermined shape. A method for manufacturing an insulation reinforcing portion of a plastic insulated cable according to claim (1). (3) Claim No. 2 (2018) in which an insulating synthetic resin tape containing a cross-linking agent is wrapped around the part of the plastic insulated cable where the insulation is to be reinforced and the synthetic resin is molded into a predetermined shape.
1) Manufacturing method of the plastic insulated cable insulation reinforcement part described in section 1). (4) The method for producing an insulation reinforcement part of a plastic insulated cable according to claim (1), wherein the parts of the plastic insulated cable to be reinforced are a connection part, a terminal part, a direct connection part to a device, and a repair part. (5) The method for manufacturing an insulation reinforcing portion of a plastic insulated cable according to claim (1), wherein the synthetic resin is polyethylene. (6) The method for producing an insulation reinforcing portion of a plastic insulated cable according to claim (1), wherein the conductive layer is made by shrinking a conductive tube containing a heat-shrinkable crosslinking agent.