JPS58169809A - Waterproof type plastic insulated cable - 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 improvements in plastic insulated cables, particularly water-shielded plastic insulated cables.

Plastic insulated cables, such as cross-linked polyethylene insulated cables, are prone to water treeing and deteriorated insulation performance when energized under water. As a means to prevent this, there is a method of applying a water-blocking layer such as lead sheathing or aluminum sheathing to the cable, but in this case there is a problem that the price and weight of the cable increase.

On the other hand, in recent years, as a solution to this difficulty, a so-called simple water-shielding plastic insulated cable has been proposed in which a water-shielding layer made of a laminated metal foil and plastic tape is interposed between the cable core and the cable sheath. There is.

The above-mentioned water-blocking layer may be formed by rolling a laminate tape in the longitudinal direction, overlapping both edges as appropriate, and then gluing the overlapping seams (hereinafter referred to as "vertical alignment type"), or 115 laminated tape
There are two types: one that is formed by horizontally wrapping with a wrap width of about 1/6 to 1/6, and then gluing the wraps (hereinafter referred to as "horizontally wound type").

However, cables with a vertical type of water shielding layer tend to generate noise in the water shielding layer during cable manufacturing and installation, and cables with a horizontally wound type water shielding layer tend to generate noise in the water shielding layer during cable manufacturing and installation. It has the disadvantage that its water-blocking properties are inferior to those with a water-blocking layer.

In view of the above-mentioned points, the present inventors attempted various studies to improve the water-blocking property of a product having a horizontally wound type water-blocking layer. It was found that the water-blocking performance could be significantly improved compared to the conventional technology by configuring the system within a range.

The present invention has been made based on the above findings.

SUMMARY OF THE INVENTION An object of the present invention is to provide a plastic insulated cable having a horizontally wound water-shielding layer that can overcome the drawbacks of the prior art described above and significantly improve its water-shielding performance.

That is, the gist of the present invention is that the wrap width t of the laminate tape is configured within a specific range of 0.9x''≦z≦tlx (where W is the laminate tape width).

The water permeability P of the horizontally wound type water shielding layer is proportional to the cross-sectional area A between the tapes of the laminate tape ramp section per cable length, and is inversely proportional to the ramp width t of the wrap section.

In other words, P is set.

On the other hand, the thickness between the tapes of the laminated tape wrap part is X1, the cable unit length is L1, the outer diameter of the water-blocking layer is D1
If the width of the laminate tape is W, then π D A-Fist L@X −t .

Therefore, pCx t(W-t, III, °7 becomes.

becomes.

From this, K becomes the minimum at t-, P is also minimized by t-÷.

After all, in theory, in the case of a horizontally wound type water-blocking layer, the water permeability will be the lowest if the wrap width of the laminate tape is half the width of the laminate tape.

However, according to experimental confirmation from a practical standpoint by the present inventors, in plastic insulated cables with a horizontally wound type water-shielding layer, the wrap width of the laminate tape within the above-mentioned specific range provides excellent results. It was found that it can exhibit water-blocking performance.

In addition, in the present invention, as the material of the metal foil, IPI
J t t/f aluminum, miniram, aluminum alloy, copper, copper alloy, lead, lead alloy, etc. are suitable, and as the material for the plastic resin layer, for example, polyethylene terephthalate, polyethylene, polyvinyl chloride, etc. are suitable. be.

If the plastic resin layer is required to be electrically conductive, a conductive agent such as carbon blank may be mixed into each of the above materials to appropriately make the materials electrically conductive.

Further, it is suitable that the metal foil has a thickness of 200 μm or less.

Next, embodiments of the water-shielding plastic insulated cable of the present invention will be explained with reference to the accompanying drawings.

It goes without saying that the present invention is not limited to this embodiment.

Figure 1 shows a horizontally wound water layer 2 attached to a cable sheath 1.
and a wire shield (metal shielding layer) 6, and FIG. 2 shows an example where a horizontally wound type water shielding layer 2 is embedded in the external conductive layer 4. .

In the case of Fig. 1, the water-blocking layer 2 consists of a laminate tape made by pasting 100-μm-thick polyethylene tape on both sides of a 50-μm-thick lead alloy foil, which is wound horizontally with a wrap width within the above-mentioned specific range. It consists of binding together.

Further, the water-blocking layer 2 is fused to the cable sheath 1 using heat generated during extrusion of the cable sheath 1.

In the case of Fig. 2, the water-blocking layer 2 is made by pasting a 100-μm-thick conductive polyethylene tape on both sides of a 50-μm-thick lead alloy foil, horizontally wrapping it with a wrap width within the above-mentioned specific range, and then It is constructed by binding the lamp parts together.

Further, the water-blocking layer 2 is fused to the inner conductive layer 41 and the outer conductive layer 42 using the heat generated during extrusion of the outer conductive layer 42.

In FIGS. 1 and 2, 5 is a Kerpul conductor, which is made of stranded copper wire. 6 is an internal conductive layer, which is made of, for example, polyethylene with carbon black, ethylene propylene rubber with carbon black, ethylene-hinyl acetate copolymer with carbon black, ethylene-ethyl acrylate copolymer with carbon black, or A tape-wrapped layer made of a blend of at least two of polyethylene, ethylene propylene rubber, ethylene-vinyl acetate copolymer, and ethylene-ethyl acetate IJL/-4 copolymer mixed with carbon black. Alternatively, it is composed of extruded layers. 7 is a cable insulator, such as polyethylene, crosslinked polyethylene (including silane crosslinked polyethylene), filled crosslinked polyethylene, vinyl,
It is made of extruded material such as ethylene propylene rubber.

Note that the outer conductive layer 4 is made of the same material as the inner conductive layer 6. The cable sheath 1 is made of extruded material such as high density polyethylene, medium density polyethylene, low density polyethylene, polyvinyl chloride, etc.

Next, the characteristics of the waterproof plastic insulated cable of the type shown in FIG. 1 in this embodiment are shown in the table below. Although the figure 2 type is omitted, it is essentially the 1st type.
It will be understood that the same effect as the diagram type can be obtained.

Table 1 Notes - 1・□ (1) The rate of occurrence of boat tree in the cable insulation and the water permeability into the cable insulation are 100 for the case without a water-blocking layer, and for all other cases without this water-blocking layer. is the ratio value to .

(2) The water permeability into the 'y-pull insulation was determined from the amount of water contained in the cable insulation.

As is clear from the above table, the water-shielding plastic insulated cable of the present invention can greatly improve its water-shielding performance compared to the conventional water-shielding plastic insulated cable.

Incidentally, the present inventors conducted Comparative Examples 2 to 6 and Examples 1 to 6.
Regarding this, we conducted an extreme bending test (bending the cable 10 times with a radius of curvature 5 times its own outer diameter) and an offset test (duration: equivalent to 100 years), and found that Comparative Example 2
In Comparative Example 6, no particular abnormalities were observed except for a large number of cracks in the wrap and a few cracks in the wraps in Comparative Example 6.The water-shielding plastic insulated cable of the present invention also exhibited exceptionally excellent performance in terms of bending properties. It was found that it has

[Brief explanation of drawings]

FIG. 1 and FIG. 2 are explanatory diagrams of an embodiment of the water-shielding type glass insulated cable of the present invention. 1: Cable sheath, 2: Horizontal winding type waterproof layer, 6:
Wire shield (metal shielding mausoleum), 4.41, 42: outer 7 conductive layers, 5: cable conductor, 6: inner conductive layer, 7: cable insulator. Education\36- $l Mother\2m

Claims (1)

[Scope of Claims] 1. In a continuous plastic insulated cable in which a horizontally wound layer of a laminate 1-p formed by forming a plastic resin layer on at least one side of a metal foil is provided between a cable insulator and a cable sheath. , its own wrap width t
A water-shielding plastic insulated cable characterized in that the above laminate tape is wound horizontally so that 9 x 'H≦t≦1.1× (where W is 1 laminated tape). 2. Aluminum, aluminum alloy as metal foil material,
The water-shielding plastic insulated cable according to claim 1, which is made of one of copper, copper alloy, lead, and lead alloy. 6. A water-shielding plastic insulated cable according to claim 1, using a metal foil having a thickness of 20 GIiyn or less. 4. The water-shielding type according to claim 1, in which the cable insulation material is one of polyethylene, cross-linked polyethylene (including silane-cross-linked polyethylene), filler-containing cross-linked polyethylene, vinyl, and ethylene propylene rubber. Plastic insulated cable. 5. The water-shielding plastic insulated cable according to claim 1, wherein the cable sheath material is one of high-density polyethylene, medium-density polyethylene, low-density polyethylene, and polyvinyl chloride. 6. The plastic resin layer material is made of one of polyethylene terephthalate, polyethylene, polyvinyl chloride, polyethylene terephthalate containing a conductive agent, polyethylene containing a conductive agent, and polyvinyl chloride containing a conductive agent. Waterproof plastic insulated cable. 1. The water-shielding polyethylene insulated cable according to claim 1, wherein a conductive layer and a metal shielding layer are interposed between the cable insulator and the horizontally wound laminate tape layer. 8. The shielding according to claim 1, wherein a conductive layer is interposed between the cable insulator and the horizontally wound laminate tape layer, and a conductive layer and a metal shielding layer are interposed between the horizontally wound laminate tape layer and the cable sheath. Water-type polyethylene insulation cable 9 The conductive layer material is one of polyethylene with carbon black, ethylene propylene rubber with carbon black, ethylene-vinyl acetate copolymer with carbon black, ethylene-ethyl acrylate copolymer with carbon black, A patent claim using a blend of at least two of the following ingredients: aluminum, polyethylene, ethylene propylene rubber, ethylene-vinyl acetate copolymer, and ethylene-ethyl acrylate copolymer, mixed with carbon black. A water-shielding plastic insulated cable according to items 7 to 8. 10. The water-shielding plastic insulated cable according to claims 7 and 8, wherein the metal shielding layer is formed using a metal tape or a large number of metal wires.