JPH0548122U - 3-strand cable - Google Patents

Abstract

(57) [Abstract] [Purpose] The step of forming a smooth body is omitted, and when the insulator 3 is extruded, the resin does not flow into the gap between the twisted conductors 1 and when the insulator 3 is peeled off, the separate film 2 is removed.
Are removed together, and the twisted conductor 1 is not discolored, and the three-strand cable 5 having further flexibility is obtained. [Structure] Polyethylene terephthalate (PET) 2a and polyethylene (PE) 2b containing a rust preventive agent for copper are provided on a twisted conductor 1 composed of a wire having a cross-sectional area of 1/19 or less of the total cross-sectional area. Laminate film 2 to PE layer 2
It is made by twisting three core wires a, each of which is covered so that b is on the outside, and on which a weather resistant polyethylene insulating layer 3 and a vinyl chloride sheath 4 are sequentially provided. [Operation / Effect] Since 19 strands are twisted, it has good flexibility, and since the intervening film 2 is surely removed by stripping off the insulator, connection work does not occur during pulling work and the workability is improved. Is good. In addition, the corrosion of the wires does not occur due to the inclusion of the rust preventive agent.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a three-strand cable having good flexibility, in which an insulating material flows into a gap between twisted conductors at the time of extrusion molding and the twisted conductor is not discolored.

[0002]

[Prior art and its problems]

 The three-strand cable that has been used so far consists of, for example, seven 2.0 mmφ electric soft copper wires that are concentrically twisted, and the twisted conductor is compressed into a so-called smooth body conductor. Polyethylene (hereinafter PE It was made by twisting three core wires with insulation and vinyl chloride sheath in order. The conventional insulated insulated wire thus constructed has a problem that it requires an extra step for forming a smooth body and has poor flexibility.

Further, in the case where the twisted conductor does not have a smooth body, when the polyethylene insulation is extruded on the twisted conductor, the resin flows into the gap between the twisted conductors and the insulator in that portion becomes thin. There is. As a solution to this problem, a separate film such as a polyethylene terephthalate film (hereinafter referred to as PET) is interposed between the twisted conductor and the insulator. However, PET is hydrolyzed in the process of extruding and bridging PE insulation, and the twisted conductor is discolored by phthalic acid generated by the decomposition. In addition, during the construction work, this separate film remains on the conductor after the insulator is stripped off, and since it is transparent, it cannot be detected because of its transparency, resulting in poor electrical connection and poor connection.

In view of the above, the present invention omits the step of forming a smooth body, and the resin does not flow into the gap of the twisted conductor during extrusion molding of the insulator, and the separate film is removed together when the insulator is stripped off. Therefore, it is an object of the present invention to provide a three-stranded cable in which the twisted conductor does not discolor and which is more flexible.

[0005]

[Means for Solving the Problems of the Invention]

 In order to solve the problems of the above invention, the present invention is a laminate of PET and PE containing a rust preventive agent for copper on a twisted conductor composed of a wire having a cross-sectional area of 1/19 or less of the total cross-sectional area. The film is covered so that the PE layer is on the outer side, and three core wires formed by successively providing a weather resistant polyethylene insulating layer and a vinyl chloride sheath on the film are twisted together.

[0006]

[Action]

 According to the present invention configured as described above, a twisted conductor composed of an element wire having a cross-sectional area of 1/19 or less of the total cross-sectional area is used, and the separate film is provided between the conductor and the insulator (insulating layer). By interposing it, the conductor and the insulator are made slippery to improve flexibility. Further, by adding a rust preventive agent for copper to the separate film, discoloration of the conductor due to hydrolysis in the extrusion-crosslinking step of the insulator is prevented. Furthermore, the separation film prevents the insulator from flowing into the twisted conductor, and the PE layer is fused and integrated with the PE insulating layer by interposing the PE surface toward the insulator side, and the insulator is peeled off. Can be removed together.

The rust preventive agent for copper used in the present invention is, in addition to benzotriazole alone, for example, benzotriazole monoethanolamine salt, benzotriazole diethylamine salt, benzotriazole cyclohexylamine salt, benzotriazole morpholine salt, Derivatives of benzotriazole such as benzotriazole isopropylamine salt and methylbenzotriazole hexylamine salt can also be used.

[0008]

【Example】

 Next, an embodiment of the present invention will be described with reference to the drawings.

As shown in FIG. 1, PET2a and PE2b containing a copper anticorrosive agent shown in FIG. 2 are laminated on a twisted conductor 1 in which 19 1.2 mmφ electric soft copper wires are concentrically twisted. The separate film 2 is covered so that the PE layer 2b faces outward, and the weather-resistant PE is extrusion-molded on this to form the insulating layer 3, and vinyl chloride is further extrusion-molded thereon to form the jacket 4 (sheath). ) Is provided and three cores are twisted together to form a three-core twisted cable 5 of the present invention.

In addition, on each core wire a, identification lines 6 for identifying phases, “black”, “blue”, and “green” are continuously formed in the length direction of the core wire surface by an auxiliary extruder during sheath extrusion molding. There is.

[0011]

[Effect of the device]

 This device is constructed as described above and has 19 strands of twisted wire, so it has good flexibility, and since the intervening film is surely removed by stripping off the insulator, no connection failure occurs during retraction work. , Its workability is good. In addition, the corrosion of the wires does not occur due to the inclusion of a rust preventive agent.

[Brief description of drawings]

FIG. 1 is a perspective view of an embodiment.

FIG. 2 is a sectional view of a laminated film.

[Explanation of symbols]

 a core wire 1 stranded conductor 2 laminated film 2a polyethylene terephthalate 2b polyethylene 3 insulating layer (insulator) 4 jacket (sheath) 5 3 core stranded cable

Claims (1)

[Scope of utility model registration request] 1. A laminated film of polyethylene terephthalate and polyethylene containing a rust preventive for copper and a polyethylene layer on the outside on a twisted conductor composed of a wire having a cross-sectional area of 1/19 or less of the total cross-sectional area. A three-strand insulated electric wire, which is formed by twisting three core wires each of which is covered with a wire and is sequentially provided with a weather-resistant polyethylene insulating layer and a vinyl chloride sheath.