JP2000215739A - Intervention for cable - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an intervention for a cable intervened between strands. SOLUTION: The intervention for a cable contains polyvinyl chloride of 100 pts.wt. and polyethylene of 5-50 pts.wt. of specific gravity not less than 0.94. By this structure, a cable which has diminished humidity absorption properties and excellent leading-out operability, does not require drying and stranding processes, and is separated easily is provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cable interposed between stranded wires.

[0002]

2. Description of the Related Art Two or more insulated wires are twisted, and a sheath (outer sheath) is put on the twisted wire to make a cable (including an electric wire).
When manufacturing a, because there is a gap between the stranded wire and the sheath,
Usually, an intervening portion is provided in this gap to ensure the roundness of the cable.

Conventionally, paper, jute or the like has been used as such an intervening material, or a resin composition to be extruded has been used.

[0004] In addition to the above-mentioned roundness, characteristics required for such an intervention include low hygroscopicity for preventing moisture from being introduced into the cable, and characteristics for preventing the cable itself from becoming heavy. Low specific gravity, and furthermore, good interleaving workability in which the interposition can be easily cut by tearing or pulling in the end processing, and good releasability in which the interposition can be easily separated from the wire insulator or sheath at the time of the interleaving. Required.

[0005]

However, in the case of the above-mentioned interposition made of paper or jute, the specific gravity is low, but the hygroscopicity is large, so that drying in a drying step is required, and the twisting process is also difficult. Since it is necessary, there is a problem that the number of steps increases.

On the other hand, in the case of the interposition made of the above resin composition, it is only necessary to extrude the cable at the time of manufacturing the cable, and there is an advantage that a drying step and a twisting step are not required. If a large amount of a large filler is contained, the specific gravity of the interposition itself becomes heavy, and the cable itself also becomes heavy, making it difficult to handle. However, there are problems such as that it cannot be easily cut at this time and that the interposition is strongly adhered to the wire insulator or the sheath side and cannot be easily peeled off.

SUMMARY OF THE INVENTION The present invention has been made in view of such conventional circumstances, and an object of the present invention is to provide a cable interposition having low hygroscopicity, particularly good workability in tapping, and excellent peelability. It is.

[0008]

According to the present invention, there is provided a cable interposition comprising 100 parts by weight of polyvinyl chloride and 5 to 50 parts by weight of polyethylene having a specific gravity of 0.94 or more.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION A cable interposition according to the present invention is a cable (including electric wires) in which two or more insulated wires are twisted and a sheath of, for example, polyvinyl chloride (PVC) is put on the twisted wires. The same type of polyvinyl chloride is used as a base polymer, and the specific gravity is 0.94 (g / cm ³ ) or more, and for example, the melt flow ratio (MFR) is 0.5 (190 ° C.) based on 100 parts by weight of the polyvinyl chloride. Polyethylene of high degree, ie high density polyethylene 5-5
0 parts by weight are added.

[0010] By the addition of this high-density polyethylene,
The mechanical strength of polyvinyl chloride, which is the base polymer, is reduced, and the adhesive strength of a sheath or stranded wire of the same type of polyvinyl chloride to the wire insulator is obtained. In other words, due to the decrease in mechanical strength, the interposition can be easily cut by tearing or pulling with a tool or hand at the time of the tapping operation, and good taping workability can be obtained. In addition, peeling from the wire insulator or the sheath side is facilitated due to a decrease in the interposed adhesive force, and good peelability is obtained.

[0011] The addition of the high-density polyethylene to 5 to 50 parts by weight with respect to 100 parts by weight of polyvinyl chloride means that if it is less than 5 parts by weight, the required decrease in mechanical strength and the required No decrease in adhesion was obtained,
If the amount exceeds the weight part, the resulting intervention becomes too hard, and the like occurs. When the interposition is hard, the workability of tapping is reduced, and the flexibility of the obtained cable is also reduced.

On the other hand, the specific gravity is 0.94 (g / cm
³ ) a polyethylene having a melt flow ratio (MFR) of about 0.5 (190 ° C.) less than, for example, 0.91;
That is, when low-density polyethylene was added, the mechanical strength was not significantly reduced as described later. The degree of polymerization of polyvinyl chloride used in the present invention may be high or low as long as extrusion molding is possible, and is not particularly limited.

In the present invention, since polyvinyl chloride is used as the base polymer, it is possible to add a filler such as a plasticizer, a stabilizer, and an inorganic material. Flame agents, coloring agents, processing aids, and the like can also be added as appropriate. For example, adding dioctyl phthalate (DOP) as a plasticizer, adding tribasic lead sulfate as a stabilizer, and adding calcium carbonate as an inorganic filler may be mentioned.

Example Cable intervening cables having the composition shown in Table 1 were prepared and used to prepare sample cables (Examples 1 to 3 and Comparative Example 1).
To 4) and various properties (tensile strength = TS (K
gf / mm ² ), tensile elongation rate = EL (%), hygroscopicity (%), workability at tapping, and peelability

Here, the manufactured cable is provided with an insulator by a water bridge on a conductor having a cross-sectional area of 2 mm ^{2 in} which seven copper wires are stranded, and three of these insulated wires are brought together to form a wire. The intervention was extrusion coated with a sheath made of flexible polyvinyl chloride (PVC). However, when the above-mentioned interposition was paper, this paper was applied to the outside on the stranded wire, and then a sheath made of soft polyvinyl chloride (PVC) was extrusion-coated.

In the above measurement, the hygroscopicity is 70 ° C.
Was immersed in hot water for 24 hours after immersion in a sheet-like sample, and the rate of change (%) after drying at 105 ° C. for 3 hours was shown. The taping workability was determined by the ease of cutting when tearing off the intervention with a tool or hand during the tapping operation. Peelability was determined by whether or not the interposition could be easily peeled from the wire insulator or sheath side. In these determinations, ◎ indicates extremely good, ○ indicates good, Δ indicates slightly good, and × indicates bad.

[0017]

[Table 1]

From Table 1, in the case of the cable interposition according to the present invention and the cable using the same (Examples 1 to 3),
It can be seen that the material has low hygroscopicity, and has good operability and peelability. In contrast, in the case of a cable interposition lacking the conditions of the present invention and a cable using the same,
Excessive hygroscopicity (Comparative Example 4), poor operability (Comparative Examples 1 to 3), poor releasability (Comparative Examples 2 to 3), too high tensile elongation (Comparative Examples 2 to 2)
3) It turns out to do. In particular, it can be seen that even with the same polyethylene, good properties cannot be obtained with low-density polyethylene (Comparative Example 3).

[0019]

As described above, according to the present invention, it is possible to obtain an interposition for a cable which has low hygroscopicity, does not require a drying step or a twisting step, and is excellent in workability and releasing property.

Claims (1)

[Claims] 1. A cable interposition comprising 100 parts by weight of polyvinyl chloride and 5 to 50 parts by weight of polyethylene having a specific gravity of 0.94 or more.