JPH0588491B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field of the Invention) The present invention relates to a method of manufacturing a rubber-coated cable having a core coating layer around the outer periphery of an insulating core.

(Technical Background of the Invention and Problems Thereof) Conventionally, as a method for vulcanizing a rubber-coated cable having a rubber coating layer on an insulating core made by extrusion coating polyethylene resin or soft polyvinyl chloride resin on a conductor, In order to prevent the insulating core from deforming due to the heat generated during vulcanization of the coating layer, a so-called low-temperature vulcanization method is known in which the rubber coating layer is vulcanized at a low temperature of 70 to 100° C. for a long period of time.

In such a low temperature vulcanization method, the rubber coating layer is coated with lead in order to prevent foaming of the rubber coating layer and to arrange the outer shape of the rubber coating layer into a concentric circle, and this is placed in a vulcanization pot etc. 10 at a temperature of about 120℃
The so-called leaded vulcanization method, which is vulcanized for ~30 hours, is used.

However, in this lead-covered vulcanization method, there is an environmental problem in that it requires the use of harmful lead, and it is also inconvenient that voids between the lead and the rubber coating layer prevent the uniform finish of the rubber coating layer. It was hot. Also, depending on the type of lead-covered machine, it may not be possible to cover the entire length of a long cable with the amount of lead extruded at one time, and in such cases, replenish lead with the insulating core stopped in the lead-covered machine. As a result, while replenishing lead, the insulating core is exposed to a high temperature atmosphere at the extrusion temperature of lead (approximately 250°C), which may cause deformation of the insulating core or damage to the insulating core due to insulation deterioration. However, it had drawbacks such as the risk of dielectric breakdown.

(Purpose of the Invention) The present invention has been made to improve these drawbacks, and it is possible to vulcanize a rubber coating layer without using a lead-covered machine, and to produce a high-quality rubber-covered cable. The object of the present invention is to provide a method of manufacturing a rubber-coated cable that can be provided.

(Summary of the Invention) The method for manufacturing a rubber-coated cable of the present invention includes the steps of vulcanizing a rubber coating layer provided on the outer periphery of an insulating core made by extrusion coating polyethylene resin or soft polyvinyl chloride resin on a conductor. A thermoplastic resin coating layer is provided around the outer periphery of the rubber coating layer, and a tape-wound layer formed by winding a non-metallic tape with a small elongation rate in the vulcanization temperature range is provided on top of the thermoplastic resin coating layer. After vulcanization, the thermoplastic resin coating layer and the tape winding layer are peeled off.

(Embodiment of the Invention) The present invention will be described below based on the drawings of one embodiment. FIG. 1 is an explanatory diagram showing the state of manufacture of a rubber-coated cable according to the present invention, and FIG. 2 is an explanatory diagram showing a state in which a thermoplastic resin coating layer and a tape winding layer are provided on the outer periphery of the rubber-coated cable. In FIGS. 1 and 2, reference numeral 1 indicates a drum on which an insulating core 2 is wound. Raw rubber such as polychlorosulfonated polyethylene is extrusion coated.

The insulating core 2 is composed of a conductor 5 coated with an insulator 6 such as polyethylene resin or soft vinyl chloride resin by extrusion. In the case of a multi-core cable, a plurality of these insulating cores 2 are twisted together with an inclusion 7 such as a jute.

Then, a thermoplastic resin is extruded and coated on the rubber coating layer 4 via a plastic extruder 8.
On this thermoplastic resin coating layer 9, in order to suppress thermal deformation during vulcanization, a tape having a small elongation rate in the vulcanization temperature range, such as a tape made of sfumos, human silk, etc., is wound. Tape winding layer 10
will be provided.

The thermoplastic resin provided on the rubber coating layer 4 is most preferably polyethylene resin or soft polyvinyl chloride resin. These resins soften at the vulcanization temperature of raw rubber (about 70 to 120°C), and are effective in adjusting the shape of the rubber coating layer 4 by the tape winding layer 10 provided thereon. This is because it can be easily peeled off after vulcanization.

The rubber coated cable semi-finished product obtained as described above is vulcanized at a temperature of 70 to 120°C in a vulcanization pot or constant temperature bath, and after the completion of vulcanization of the rubber coating layer 4, the thermoplastic resin layer 9 and The tape wrap layer 10 is peeled off, resulting in a finished rubber coated cable.

In the figure, reference numeral 11 indicates a restraining winding layer, 12 a cooling water tank, 13 a take-up machine, and 14 a winding machine.

Figure 3 shows PTC, which is made of a crystalline thermoplastic polymer and a conductive filler, as a thermoplastic resin coating layer.
An example is shown in which the composition was extrusion coated. In addition, in FIG. 3, the same parts as in FIG. 2 are given the same reference numerals. In the embodiment shown in FIG. 3, two current-carrying conductors 16 are embedded in the thermoplastic resin coating layer 15, and by passing a current through the current-carrying conductors 16, the thermoplastic resin coating layer 15 is heated. The temperature can be adjusted to 70-120°C, and the rubber coating layer 4 can be vulcanized at this temperature. In this example, the vulcanization temperature is uniform, the variation in the degree of vulcanization in the length direction is small, and the self-temperature control function (when the temperature exceeds a certain temperature, the resistance increases rapidly, resulting in a decrease in the amount of heat generated) This has the advantage that there is less risk of thermal damage to the insulator or rubber coating layer 4 due to excessive temperature rise.

Example 1 An insulated core (approximately
100 m) was coated with raw polychloroprene rubber with a thickness of 1.5 mm, the outer periphery of this was coated with polyethylene resin by extrusion, and human silk tape was further wrapped around the outer periphery with a 1/2 wrap.

The obtained semi-finished product was heated in a vulcanization pot for 20 hours with the surface temperature adjusted to 90°C. Thereafter, the polyethylene coating layer and silk tape were peeled off to obtain a rubber-coated cable. This rubber-covered cable had a smooth appearance, and the results of physical tests such as insulation resistance and heat deformation tests were completely equivalent to those obtained by the conventional lead-covered sulfurization method.

Example 2 The outer periphery of the polychloroprene rubber of Example 1 was made by mixing 40 parts by weight of conductive carbon black with 100 parts by weight of polyethylene and having an initial resistivity of 3Ω・cm.
The PTC composition was extrusion coated together with two copper wires, and a 1/2 wrap of silk tape was wrapped around the outer circumference of the PTC composition.
Then, a 100V AC power supply was applied to the two copper wires with the voltage reduced by a slide transformer, and vulcanization was carried out for 22 hours while maintaining the surface temperature of the PTC composition at 85°C.

Thereafter, the PTC composition was stripped off using the copper wire as a rip cord to obtain a rubber-coated cable.

In this example as well, excellent data similar to Example 1 were obtained.

As described above, in the invention with such a structure, the rubber coating layer can be vulcanized without using a lead-containing machine, so the work can be done without handling harmful lead, and there is no restriction on manufacturing length. To obtain a rubber-covered cable that is smooth and has a good appearance, while being able to manufacture a long rubber-covered cable, and also without causing moth-eaten appearance defects seen in conventional lead-covered vulcanization methods. I can do it. In addition, the polyethylene resin or vinyl chloride resin that makes up the thermoplastic resin coating layer can be recycled and used.
Sfumos, human silk, etc. that make up these resins and tape wrapping layers can be easily damaged with a knife, so be careful not to use a knife when peeling off the thermoplastic resin coating layer and tape wrapping layer. If you scratch it in the axial direction, you can remove both at the same time. In addition, since the semi-finished rubber-coated cable cable can be wound up on a winding machine with the thermoplastic resin layer provided on the rubber coating layer, conventional rubber without a thermoplastic resin layer on the rubber coating layer can be Compared to the case where a coated cable is wound up, the hardness of the thermoplastic resin layer can protect against directional deformation caused by winding up with a winding machine.

(Effects of the Invention) As described above, in the present invention, work can be performed without handling harmful lead, long rubber-coated cables can be manufactured without restrictions on manufacturing length, and the appearance can be improved. A good rubber coated cable can be obtained. Furthermore, when peeling off the thermoplastic resin coating layer and the tape wrapping layer, it is possible to make scratches in the axial direction with a knife, so the thermoplastic resin coating layer and the tape wrapping layer can be peeled off at the same time. Moreover, the hardness of the thermoplastic resin coating layer can protect the rubber-coated cable from directional deformation caused by winding it up on a winding machine.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing the manufacturing status of a rubber-covered cable according to the present invention, FIG. 2 is a cross-sectional view showing a state in which a thermoplastic resin coating layer and a tape winding layer are provided on the outer periphery of the rubber-covered cable, and FIG. This figure is a cross-sectional view showing another embodiment of the semi-finished product shown in FIG. 2. DESCRIPTION OF SYMBOLS 1...Drum, 2...Insulating core, 3...Rubber extruder, 4...Rubber coating layer, 5...Conductor, 6...Insulator, 9...Thermoplastic resin coating layer, 10...Tape winding Cycle layer.

Claims (1)

[Claims] 1. When vulcanizing the rubber coating layer provided on the outer periphery of the insulating core made by extrusion coating polyethylene resin or soft polyvinyl chloride resin on the conductor, providing a thermoplastic resin coating layer on the outer periphery of the rubber coating layer,
A tape winding layer formed by winding a non-metallic tape with a small elongation rate in the vulcanization temperature range is provided on this, and after the rubber coating layer is vulcanized at a low temperature, the thermoplastic resin coating layer and the tape winding layer are formed. A method for manufacturing a rubber-coated cable, characterized by peeling off a circuit layer.