JP3140334B2 - Wiring cable for low voltage - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a low-voltage distribution cable, and more particularly to a 600V vinyl insulated vinyl sheath cable (VV).

[0002]

2. Description of the Related Art A vinyl insulated vinyl sheath cable rated at 600 V is economically excellent, and is widely used especially for outdoor low pressure. In the conventional vinyl insulated vinyl sheathed cable, as shown in FIGS. 4 and 5, the vinyl insulated vinyl sheathed cable 1A is a round cable, and a plurality of wire cores 3 formed by insulatingly coating a copper conductor 2 are used. After twisting an interposition such as a jute 4 into the gap, and wrapping a tape 5 such as a non-woven fabric over the twisted jute 4 so that the twisted
A VC (polyvinyl chloride) sheath 6 was provided as an exterior. For this reason, many steps are required at the time of manufacture,
During the construction work, it was necessary to remove the tape and jute, and the construction work was inefficient. In addition, copper serving as a conductor, P
Since there are a wide variety of materials such as VC, jute, and holding tape, there is a problem that it takes time and effort to separate, and it is difficult to dispose or recycle.

[0003] The applicant of the present invention has developed a vinyl insulated vinyl sheathed cable in which the space between the cable cores is filled with PVC putty instead of jute to produce all but a copper conductor as a PVC resin composition. It has already been proposed in the public technical report (public technical number 94-22267). As a result, productivity in cable manufacturing can be improved, labor can be saved during cable construction, and cable recycling processing has also been facilitated.

[0004]

As described above, all of the prior problems have been successfully solved by the proposal of the present applicant. However, in view of the application, flexibility (bending stress) and reduction in weight are reduced. Improvement in (weight) was desired. The present invention has been made in view of the above circumstances, and provides a low-voltage wiring cable with improved flexibility and light weight, which facilitates transportation and routing work during construction and at the same time improves productivity as in the past. And to facilitate the recycling process.

[0005]

To achieve the above object, a low-voltage wiring cable according to the present invention comprises a low-voltage wiring cable in which a plurality of insulated wires are filled with interposition. Has been launched in PVC (polyvinyl chloride).
Combining a foaming agent and a release agent containing silicone,
Foaming so that the bending stress is 2N (Newton) or less
It is characterized by being in the present.

[0006]

In the wiring cable for low pressure according to the present invention, a foaming agent and a release agent containing silicone are provided in the gap between the insulated wires.
(Hereinafter referred to as “foamed PVC”)
An interposition is arranged, and the bending stress of the foaming interposition is 2N (d)
With the following structure, flexibility and weight can be realized by the foamed structure, and workability can be improved due to easy removal of the intervening foamed PVC.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of a low-voltage wiring cable according to the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a perspective view showing a configuration of a low-voltage wiring cable according to the present invention, and FIG. 2 is a front view of the low-voltage wiring cable of FIG. In this embodiment, a case will be described in which a two-core vinyl insulated vinyl sheath cable is applied as a low-voltage wiring cable. Further, the same parts as those of the conventional structure are denoted by the same reference numerals, and the description is omitted. In the figure, a copper conductor 2 is subjected to PVC insulation treatment by extrusion, and an insulated wire core 3 is provided.
(PVC insulator) is formed. The two insulated wire cores 3
While being mutually twisted along the axial direction, a foamed PVC intervening member 7 described later is filled in the gap between the wire cores 3 for the purpose of ensuring a circular shape of the cable. Then, the vinyl insulated vinyl sheath cable 1 is configured by providing a PVC sheath 6 covering the insulated wire core 3 and the foamed PVC intervening member 7 on the exterior. With the above configuration, the vinyl insulated vinyl sheath cable 1 in the present embodiment is configured as a PVC resin composition except for the copper conductor 2. Here, the composition of the PVC putty that is the foamed PVC intervening material is shown in Table 1 below.

[0008]

[Table 1]

As shown in Table 1 above, by blending a low-temperature foaming agent in a PVC putty, the low-temperature foaming agent completely foams at a foaming temperature of 58 to 60 ° C. to form a foamed PVC intervening layer 7. This foaming agent has an optimal content of 2% by weight described in the table, and is preferably used in the range of 2.0 to 2.2. Easiness of peeling is insufficient, and if it is 2.3 or more, workability deteriorates. Further, as is clear from Table 1, the release agent is compounded in the PVC putty, so that the PVC insulator 3, the foamed PVC intervention 7, and the PVC sheath 6 of the finished product cable are provided.
Are easily separated from each other, and therefore, the work of stripping the foamed PVC intervening member 7 in the cable construction work is facilitated. In addition, the silicone used as a release agent has an optimal content of 3% by weight described in the table, and preferably 2.8 to 3.2.
Used in the range. When it is 3.3 or more, it bleeds and the releasability is impaired. On the contrary, when it is less than 2.8, the release effect cannot be expected and the ease of peeling cannot be obtained.

Next, the manufacturing process of the vinyl insulated vinyl sheath cable 1 having the above configuration will be described. In the manufacturing process shown in FIG. 3, the two PVC insulators 3 in which the copper conductors 2 have been insulated in the previous process are continuously transported in the horizontal direction (from left to right in the figure) and integrated with the feeder 10 for preheating. It is introduced into the die 11. Here, the PVC putty having the resin composition shown in Table 1 is continuously injected from the feeder 10 into the preheating die 11, and the PVC putty is heated by the preheating die 11 while the foamed PVC intervening layer 7 is interposed between the PVC insulators 3 (see FIGS. 1 and 2). Reference). During this filling, the low-temperature foaming agent incorporated in the PVC putty undergoes complete foaming and gelation proceeds. At that time, the thixotropy-imparting agent blended in the PVC putty prevents the PVC putty from dripping, and the gelling is promoted by the gelling accelerator epoxy resin and triethylenetetramine (TETA).
Thereafter, the wire is guided to the sheath extruder 12, and the PV
The C sheath 6 is coated as an exterior and commercialized. At this time, the PVC putty is further heated by the sheath heat, and the gelation is completed.

Next, in order to show the improvement of the characteristics of the vinyl insulated vinyl sheath cable 1 manufactured in accordance with the above-mentioned process by the foamed PVC intervening material 7, based on the results of experiments conducted by the present applicant,
Table 2 below shows a comparative example of the wire with PVC intervening without a foaming agent.

[0012]

[Table 2]

From Table 2, it can be seen that the flexibility of the present invention is smaller than that of the comparative example, that is, the bending stress is 2 N (Newton) or less. Therefore,
The thing of this invention is excellent in bending workability, and the wiring work at the time of construction work is easy. In addition, in terms of weight reduction and ease of stripping, the foamed intervening material according to the present invention is superior to the comparative example, and it can be seen that the cable intervening can be efficiently removed especially by the effect of the release agent.

[0014]

As described above, the low-voltage wiring cable according to the present invention has a foamed PVC intervening material serving as a foaming material in the gap between the insulated wires, so that the conventional PVC intervening material is arranged. The bending stress and the weight reduction are remarkably excellent as compared with, and the easiness of peeling is also improved, so that the construction work is favorably performed. In addition, compared to the conventional method using the jute interposition, the construction work is only removal of the foamed PVC interposition, and the labor for removing the holding tape and the jute can be omitted, so that the labor of the cable construction work can be reduced. In addition, the finished cable according to the present invention is made of only copper and PVC, and can be easily separated completely from copper and PVC, so that the cable can be easily recycled.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a configuration of a low-voltage wiring cable according to the present invention.

FIG. 2 is a front view of the low-voltage wiring cable shown in FIG. 1;

FIG. 3 is a diagram illustrating a manufacturing process of a low-voltage wiring cable.

FIG. 4 is a perspective view showing a configuration of a conventional low-voltage wiring cable.

FIG. 5 is a front view of the low-voltage wiring cable of FIG. 4;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Vinyl-insulated vinyl sheath cable 2 Copper conductor 3 Insulated wire core (PVC insulator) 6 PVC sheath 10 Feeder 11 Preheating die 12 Sheath extruder

Claims (1)

(57) [Claims] 1. A low-voltage wiring cable in which an intervening space is filled between a plurality of insulated wires.
(Polyvinyl chloride) contains a foaming agent and silicone
And a mold release agent, and the bending stress is 2N (New
(C) A low-voltage wiring cable characterized in that the foaming is as follows .