JPS6043611B2 - Multi-core cable manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a multi-core cable by heating and vulcanizing under normal pressure.

A method for manufacturing a vulcanized cable is known in which rubber or plastic is heated and vulcanized under normal pressure using a vulcanizing bath filled with a heating medium such as molten salt.

The vulcanization bath used in this case does not need to have a pressure-resistant structure unlike vulcanization equipment that uses high-pressure steam as the heating medium.
Moreover, since there is no need for direct connection to the extruder in an airtight manner, an extremely simple structure is sufficient. However, when a sheath made of unvulcanized rubber or plastic is extruded and coated on the outside of the cable stranded core with a chute etc., and then the sheath is vulcanized by the above-mentioned atmospheric pressure vulcanization method, the cable Due to the expansion of the gas inside the cable or the vaporization of moisture, volatile organic substances, etc. contained in the cable, the internal pressure of the cable increases and becomes higher than the cable external pressure, which causes the sheath to expand and makes it difficult to finish the cable to the specified outer diameter. There are drawbacks. Furthermore, during vulcanization, the amount of heat required to vulcanize the sheath is absorbed by an intervening object other than the sheath or by the cable core, which poses a problem in terms of uniform vulcanization of the sheath or vulcanization efficiency. In view of the above, the present invention proposes a manufacturing method that can manufacture a multi-core cable of a predetermined size by an atmospheric pressure vulcanization method, can achieve uniform vulcanization of the sheath, and has high vulcanization efficiency. A tape that does not generate gas even when heated to the vulcanization temperature and has heat insulating properties is applied to the outside of the collective core, and then an outer layer made of unvulcanized rubber or plastic is applied under reduced pressure. It is characterized by being heated and vulcanized under normal pressure.

Hereinafter, the present invention will be explained in detail with reference to Examples.

In the figure, reference numeral 1 denotes a cable assembly core made by twisting three wire cores insulated with vulcanized rubber and having an interposition between each wire core.A sheath 1, which will be described later, is placed on the outside of the cable assembly core when vulcanized. In order to prevent thermal melting of the intervening material or vaporization of moisture, volatile substances, etc. contained in the intervening material, the tape 11, which does not melt at the vulcanization temperature and has an insulating effect, is wound or stretched vertically. It is provided by means of. As the tape 11, for example, a non-woven fabric or foam material such as polyester or nylon, or a plastic tape with an air layer formed by embossing or the like is used, as well as a paper tape, cotton, etc. that is sufficiently dry to the extent that no moisture is generated even at the vulcanization temperature. cloth tape is used. The cable collecting core 1 coated with the tape 11 is continuously supplied to the nipple 21 through a sealed tube 22 which is hermetically screwed onto the nipple 21 of the crosshead 2 for rubber extrusion molding. The tube is a long tube (for example, 30c1n) having an inner diameter slightly larger than the outer diameter of the tube, and its inner wall surface is lined with polyurethane foam (not shown) containing closed cells. Therefore, the space between the surface of the cable collecting core 1 and the inner surface of the seal tube 22 is airtight, and the inside of the nipple 21 is continuously evacuated by an exhaust pump (not shown) communicating with the exhaust pipe 23, so that there is no disconnection. It is kept under reduced pressure. In this case, the degree of pressure reduction is such that even when the air remaining in the cable assembly core is heated to the vulcanization temperature and expanded, the pressure remains below atmospheric pressure.
For example, if the vulcanization temperature is 200'C, 400Tf
Evacuate to about 0 nHg or lower. On the other hand, the crosshead 2 is equipped with a vent extruder (not shown), such as a twin-screw vent type rubber extruder manufactured by Mitsuha Seisakusho (this extruder has a vacuum between the first stage extruder and the second stage extruder). The rubber extruded from the first stage extruder is shredded in the vacuum drying room, dried, and then extruded from the second stage extruder). An unvulcanized chloroprene sheath compound composition containing the above is supplied after being sufficiently dried and deaerated, and the above chloroprene sheath compound composition is molded onto the cable assembly core 1 which is passed through the nipple 21 and exposed to reduced pressure. An unvulcanized cable 13 having a sheath layer 12 is thus extruded from the outlet of the crosshead 2.
The cable 13 is then introduced into the vulcanization bath 3 filled with one type of heating medium such as molten mixed salt, molten metal, polyalkylene glycol, etc., through an inlet 31 provided in the side wall of the bath, and the heating medium is After passing through the vulcanization bath 3, it is led out through an outlet 32 provided in the side wall of the vulcanization bath 3. The vulcanization bath 3 has an inlet port 31 and an outlet port 32, and auxiliary tanks 33, 3 are provided on the outside of each side wall to collect the heating medium flowing out from the respective ports.
4, and the heating medium collected in each auxiliary tank is
A reflux device (which collects water at a certain point, adjusts the temperature, and refluxes it back to the vulcanization bath)
(not shown). Further, the heating medium in the bathtub is heated and maintained by a heater 35 installed in the bathtub at a temperature at which rubber and plastics are sufficiently vulcanized, for example, 200.degree. At this time, since the heat insulating tape 11 is applied to the outside of the cable assembly core 1, the heat of the vulcanization is transferred to the tape 1.
Since the sheath layer of the cable 13 that has passed through the vulcanization bath is efficiently and uniformly vulcanized, the cable 13 is blocked by the cable 1 and hardly escapes to the cable collecting core 1 side. Moreover, the inside of the cable 13 is deaerated in advance, and the cable assembly core 1 is covered with a tape 11 which has insulation properties against the above-mentioned vulcanization temperature.
Since this is done, gas will not be generated from interposition etc. Therefore, even during heating and vulcanization, the inside of the cable 13 is under a pressure equal to or lower than atmospheric pressure, so the sheath 12 does not expand, and therefore a cable with a predetermined outer diameter can be obtained. The cable 13 then passes through a water washing device 4 installed below the vulcanization bath, then a surface cleaning device such as a wiper 5, and then is wound up. The present invention is not limited to the above embodiments. For example, in addition to the above-mentioned vulcanization bath filled with the liquid heating medium, the vulcanization equipment may include a particle fluidization bath,
A hot air bath using hot air or nitrogen as a heating medium may also be used. Further, if necessary, a precoater may be installed between the crosshead of the extruder and the vulcanization device to coat the surface of the unvulcanized cable with talc, silicone oil, etc. before proceeding to the subsequent steps. As is well known, the above-mentioned application of talc, silicone oil, etc. serves to prevent the heating medium from adhering to the surface of the unvulcanized object, which would impede its properties after vulcanization. be. Incidentally, the present invention is based on 3 shown in the above embodiments.
Not only core cables but also multi-core cables with two or more cores can be manufactured with predetermined dimensions.

As described in detail above, according to the method for manufacturing a multi-core cable of the present invention, a multi-core cable of a predetermined size can be manufactured, and the vulcanization efficiency is high and the sheath can be uniformly vulcanized. Furthermore, since a tape with a heat insulating effect is used on the outside of the cable assembly core, the interposition between the cable cores is made of heat-resistant high melting point resin such as polyester resin, etc.
It also has the advantage that polyethylene, polypropylene, etc. having a melting point below the vulcanization temperature can be used, or even other suitable materials can be used.

[Brief explanation of the drawing]

The figure is an explanatory view for explaining one embodiment of the method for manufacturing a multi-core cable of the present invention.

Claims (1)

[Claims] 1. A tape is applied to the outside of the cable assembly core that does not generate gas even when heated at vulcanization temperature and has heat insulating properties. Next, an outer layer made of unvulcanized rubber or plastic is applied under reduced pressure, and then continuous A method for manufacturing a multi-core cable, characterized in that the outer layer is heated and vulcanized under normal pressure to form a cable having a substantially circular cross-sectional outline.