JPS61161614A - Manufacture of water shielding type 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] [Field of Industrial Application] The present invention provides a water-shielding cable in which a water-shielding tape can be easily formed on a power cable core even if a water-shielding tape with relatively low heat resistance is used. Relating to a manufacturing method.

It is well known that moisture that penetrates the cable sheath and enters the electrical insulation layer impairs various properties of the cable. For example, in the case of power cables, there is a problem of water tree formation in the insulating layer, while in the case of communication cables, the insulation properties of the insulating layer deteriorate and interference occurs. In order to prevent water from entering, a method has been proposed in which a water-blocking tape is used to vertically support a cable core, and a sheath is placed on top of the cable core. In this method, a water-blocking tape layer is formed on a cable core using a molding die, and then a sheath layer is further formed by passing the cable through a sheath cross head.

The water-shielding tape used in this method is usually a water-shielding tape as shown in FIG. 2 so that it will not break even under tension. This is because the tension generated at the homing part of the waterproof tape is concentrated at the point when it passes through the sheath cross head, so the film layer (i.e., the heat-resistant organic polymer layer (5)) has excellent strength even at high temperatures. This is because it is necessary to have a structure that includes

That is, in order to wrap the waterproof tape around the cable core so that there is no gap between the waterproof tape and the cable core, tension is applied to the waterproof tape and it is attached vertically to the cable core. However, in this case, at high temperature of the extruded vinyl chloride polymer for the sheath, the vinyl chloride polymer layers (2) and (3) as well as the adhesive layer (4) of the waterproof tape
loses its mechanical strength completely due to the softening of its constituent materials, and tension is applied only to the lead foil (11), which causes the water-blocking tape to break.In order to prevent this breakage, a heat-resistant organic polymer layer (5) is applied. It will be established.

However, manufacturing such a water-shielding tape with a total thickness of 5N is extremely complicated, so a water-shielding cable that can be manufactured and has sufficient water-shielding properties even if a smaller layer of water-shielding tape is used. A manufacturing method is eagerly awaited.

[Problem that the invention seeks to solve]

The object of the present invention is to provide a water-shielding tape that does not necessarily have good heat resistance, such as a water-shielding tape lacking the heat-resistant organic polymer layer (5) (a water-shielding tape whose strength decreases at about 180°C). Another object of the present invention is to provide a method for manufacturing a water-shielding electric cable in which the water-shielding tape layer can be easily provided on a cable core.

[Means for solving problems]

The present invention is made by forming a water-shielding tape on a cable core using a molding die and then passing it through a sheath cross head to form a water-shielding tape layer on the cable core and a sheath layer thereon. The present invention relates to a method for producing a water-shielding cable, characterized in that the cable core on which the water-shielding tape layer is formed is pressed down with a rough winding tape at the time of exiting from a molding die during production of the cable.

The rough winding tape used in the present invention has heat resistance to the extent that it does not soften due to the high temperature of the sheath polymer (for example, does not soften at 180°C), and adheres to the sheath and water-shielding tape by the heat during sheath extrusion. There are no particular restrictions if you are Shiruchi. For example, as shown in FIG. 3, adhesive 1ii is applied to both sides of the tension member (6).
(7) A structure formed by forming (7') is exemplified.

Here, as the tension member, it is preferable that the strength of the above-mentioned sheath polymer does not decrease even at high temperatures. Specific examples of such materials include polyethylene terephthalate, aromatic polyamides [Keplar (manufactured by DuPont), Nomenox (manufactured by DuPont)],
Examples include fibers made of glass, carbon, etc., nonwoven fabrics, etc., and films of polyester, nylon, polyether sulfone, polyether ether ketone, etc.

The adhesive that forms the adhesive layer may be one that can adhere to the sheath and water-blocking tape through the heat generated during extrusion of the sheath.
There are no particular restrictions. Such adhesives include, for example, vinyl chloride/vinyl acetate copolymer, thermoplastic polyester,
Examples include ethylene/vinyl acetate copolymer.

In the present invention, the rough winding tape is usually formed by forming a water-shielding tape on a cable core and then winding it on the water-shielding tape at the time of exit from a forming die. The mode is
For example, as shown in FIG. 1, a cable core is formed by winding the water-shielding tape at appropriate intervals so that tension is not concentrated on a portion of the tape. Of course, lap winding may be used, but gap winding is preferable. In the case of gap winding, the surface of the cable is covered with the coarse winding tape.
Wrap wrapping is preferred to cover about 60%, especially about 5 to 30%.

The manufacturing method of the present invention can be applied to, for example, manufacturing power cables, communication cables, and the like.

[Action/Effect]

In this way, since the water-shielding tape is fixed onto the cable core by the rough wrapping tape, the tension applied to the water-shielding tape is not concentrated on the sheath cross head.

Therefore, the present invention can also be achieved by using a water-shielding tape that has a certain degree of strength (for example, the water-shielding tape in which the heat-resistant organic polymer layer (5) of the water-shielding tape in FIG. 2 is removed). The desired cable can be manufactured.

[Examples/Comparative Examples/Test Examples]

A 66 kvs 1 × 200 mta2 cross-linked polyethylene insulated vinyl chloride sheathed cable was coated with a water-shielding tape layer using the water-shielding tape and loosely wound tape listed in Table 1 under the conditions shown in Table 1, and then heated at 180°C. A water-shielding cable was manufactured using vinyl chloride resin. The thus obtained water-shielding cable was examined for its water-shielding layer formation properties, and the results are also listed in Table 1.

In addition, each abbreviation in Table 1 means the following, respectively.

vc: Vinyl chloride/vinyl acetate/maleic acid tricopolymer coating (10μ) Pb: Lead foil (50μ) spoc: Semiconductive vinyl chloride film (80μ) v
C/Pb/5POC: Waterproof tape is VC coated, lead foil,
and 5 pvc films were laminated in this order.

PES: Thermoplastic polyester PET: Polyethylene terephthalate EVA:
Ethylene/vinyl acetate copolymer (blank below) Table 1

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing an embodiment of the manufacturing method of the present invention,
Figure 2 is a cross-sectional view of conventionally used water-blocking tape, Figure 3
The figure is a sectional view of the rough winding tape. l...Lead foil 2 and 3...Polyvinyl chloride layer 4...Adhesive layer 5...Heat-resistant organic polymer layer 6...Tension member 7 and (7゛)...Adhesive layer 8...Molding tie 9... Sheath cross head 10...
Rough winding tape

Claims (1)

[Claims] A cable is manufactured by forming a water-shielding tape on a cable core using a molding die and then passing it through a sheath cross head to form a water-shielding tape layer on the cable core and a sheath layer on top of that. A method for producing a water-shielding type cable, which comprises pressing the water-shielding tape layer-formed cable core with a coarse winding tape at the time it leaves a molding die.