JPH0534794B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a method of molding a crosslinked polyolefin insulated cable connection.

[Technical background of the invention and its problems] In recent years, as a method for forming an insulator connection part of a crosslinked polyolefin insulated cable, a mold is fitted around the outer periphery of the conductor connection part, and heating and melting is carried out in the cavity of this mold. A metal molding method is used in which a crosslinkable polyolefin composition is press-fitted and cured.

However, in such conventional molding methods, when setting the conductor connection part of the cable in the mold, the cable is only fixed at the cable insulator gripping parts at both ends of the mold.
When the heated and molten polyolefin composition is press-fitted, the set conductor connection part and the following cable insulation move, causing uneven thickness in the mold, making it impossible to obtain an insulator connection part with good characteristics. There were flaws.

[Object of the Invention] The present invention has been made in order to eliminate such conventional drawbacks, and it is an object of the present invention to provide a method for easily molding an insulator connection portion with excellent electrical and mechanical properties without uneven thickness. It is something.

[Summary of the Invention] That is, the present invention involves fitting a two-split mold having a cavity corresponding to the shape of the insulator connection portion to be molded onto the outer periphery of the conductor connection portion of a crosslinked polyolefin insulated cable, and heating the inside of the cavity. In a method for molding a crosslinked polyolefin insulated cable connection part in which a molten crosslinkable polyolefin composition is press-fitted and cured, a spacer made of a crosslinked polyolefin of the same quality as the polyolefin composition is placed between the conductor connection part and the mold; The present invention is characterized in that the crosslinkable polyolefin composition is press-fitted by inserting the conductor connection portion into the cavity so as to be coaxially fixed therein.

[Embodiment of the Invention] Hereinafter, an embodiment of the present invention shown in the drawings will be described in detail.

In FIG. 1, numeral 1 indicates an upper mold 1a and a lower mold 1b.
This figure shows a two-split mold for molding a cable insulator connection part, which has a shape cavity 2 of the insulator connection part to be molded, and a cylindrical insulator grip part 3 continuous to both ends of the cavity 2.

The method of the present invention is carried out using such a mold, for example, as follows.

That is, first, when fitting the split mold 1 onto the outer periphery of the conductor connection part 5 of the crosslinked polyolefin insulated cable 4, a spacer 6 made of crosslinked polyolefin is inserted so that the conductor connection part 5 is fixed coaxially within the cavity 2. is inserted between the upper mold 1a and the lower mold 1b and the conductor connection portion 5, and then the insulator 4a of the crosslinked polyolefin insulated cable 4 is gripped by the insulator gripping portion 3 of the split mold via the packing P.

The spacer 6 has a columnar shape, for example, as shown in FIG. 2, and is provided with a plurality of resin flow holes 6H for freely circulating the press-fitted molten compound.

After the mold 1 is fitted around the outer periphery of the conductor connection portion in this manner, a heated and melted crosslinkable polyolefin composition is press-fitted into the cavity 2 through the resin press-fit hole 7 provided in the mold 1. As the above composition, in addition to a polyolefin composition containing a crosslinking agent, a water-crosslinkable silyl-modified polyolefin composition can also be used. At this time, since the spacer is made of crosslinked polyolefin, it will not melt at the press-in temperature of the composition, and movement of the conductor connection portion 5 is suppressed. Moreover, since the spacer is of the same quality as the press-fitted composition, the two are completely integrated and the electrical properties are also good. After the cavity is completely filled with the heated molten resin in this manner, the mold is allowed to cool to solidify the composition in the cavity 2, and then the two-split mold is opened.

The mold connection part formed in this way is finished by shaping the irregularities formed by the joints of the two split molds, and then crosslinked by a prescribed crosslinking operation to form a crosslinked polyolefin that is integrated with the spacer. Form an insulator connection.

Note that the shape and insertion position of the spacer in the present invention are not limited to the above-mentioned embodiments, and any spacer may be used as long as it is possible to coaxially fix the conductor connection portion and the cable insulators following both ends to the cavity.

[Effects of the Invention] As described above, according to the present invention, when fitting a mold into a conductor connection part, a spacer made of crosslinked polyolefin is inserted so that the conductor connection part is coaxially fixed to the cavity. By doing so, it is possible to mold an insulator connection portion with good characteristics without uneven thickness.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view for explaining one embodiment of the present invention, and FIG. 2 is an enlarged perspective view of the spacer in FIG. 1. 1...Half-split mold, 1a...Upper mold, 1b...
Lower mold, 2... Cavity, 3... Insulator gripping part,
4...Crosslinked polyolefin insulated cable, 5...
Conductor connection part, 6...Spacer, 6H...Resin flow hole.

Claims (1)

[Claims] 1. A two-split mold having a cavity corresponding to the shape of the insulator connection portion to be molded is fitted over the outer periphery of the conductor connection portion of the crosslinked polyolefin insulated cable, and a heated and melted mold is placed in the cavity. In a method for molding a crosslinked polyolefin insulated cable connection part in which a crosslinkable polyolefin composition is press-fitted and cured, a spacer made of crosslinked polyolefin of the same quality as the polyolefin composition is placed between the conductor connection part and the mold. A method for molding a crosslinked polyolefin insulated cable connection part, characterized in that the crosslinkable polyolefin composition is press-fitted by inserting the crosslinkable polyolefin composition so as to be coaxially fixed in the cavity. 2. The crosslinked polyolefin insulation according to claim 1, wherein the spacer made of crosslinked polyolefin has a large number of holes through which a heat-melted crosslinkable polyolefin composition can flow. Molding method for cable connections.