JPH03254018A - Manufacture of of ribbon electric cable - Google Patents

Abstract

PURPOSE:To achieve high dimensional precision by applying a thermoplastic resin adhesive with a lower melting point than a plastic coating to core wires, arranging a plurality of core wires closely in parallel, and heating them at a middle temperature to bind them, while moving them on. CONSTITUTION:A conductor 2 is coated with plastic coating 3 and then a thermoplastic resin adhesive with lower melting point than that of the coating 3 (e.g., vinyl chloride-vinyl acetate copolymer-soluble type adhesive) is applied to the coating. Arranged in parallel and moved on, a plurality of core wires 1 prepared in this way are heated at the middle temperature between the melt ing point of the coating 3 and that of the adhesive so as to bind and unite neighboring core wires each other to obtain a ribbon electric cable.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for manufacturing ribbon electric wires used in electronic devices and the like.

[Conventional technology]

The wiring space factor is good and compact to meet the demands for lower cost and improved reliability of wiring connections due to the increasing precision and miniaturization of computers and other electronic equipment, which has led to higher wiring density and simplification. Because it allows for easy wiring,
Ribbon electric wires are widely used, which are made by arranging a required number of wire cores in which the conductor is coated with plastic in close contact with each other in parallel in a flat plate shape, and bonding the plastic coats of adjacent wire cores together to integrate them. These wires are usually used by attaching a connector to the terminal, but it is easy to attach a connector to the terminal.
In addition, good dimensional accuracy of each part is required to ensure reliability.

Examples of this type of ribbon wire are shown in cross-sectional views in FIGS. 1 and 2. In the ribbon wire shown in FIG.
and a plastic coating (insulating layer) 3 such as polyvinyl chloride provided thereon.The required number of wire cores 1 are closely arranged in parallel, and the plastic coating (insulating layer) 3 of the adjacent wire cores 1 is 3 layers are joined together and integrated.

In the ribbon electric wire shown in FIG. 2, the wire core 4 has a coaxial core structure, and the wire core 4 includes a conductor 5, an insulating layer 6 made of foamed polyethylene, etc. applied thereon, and a copper wire. It consists of a retardation layer 7 as an outer conductor consisting of a material such as a retardation layer 7 as an outer conductor, and a plastic coating (outer coating) 8 made of polyvinyl chloride or the like.Similarly to the above, the required number of wire cores 4 are closely arranged in parallel and adjacent cores are The outer coverings 8 of 4 are joined together and integrated.

The plastic layers whose surfaces are exposed, such as the plastic coating (insulating layer) 3 in FIG. 1 and the plastic coating (outer coating) 8 in FIG. 2, will hereinafter be generally referred to as plastic coatings.

In manufacturing a ribbon electric wire having such a structure, methods for joining adjacent wire cores to each other can be roughly divided into a method of joining by heat fusion and a method of joining using an adhesive. An outline of these joining methods is shown below.

The thermal fusion bonding method involves heating and pressing a group of wire cores arranged in parallel from both sides using a hot press to melt the plastic coating of the adjacent wire cores, and then cooling and joining them.

A method using adhesive is to apply adhesive (sometimes only a solvent) onto a group of wire cores arranged in close contact with each other, apply pressure from both sides, and evaporate the solvent by drying at room temperature. A common method is to bond plastic coatings.

C Problems to be Solved by the Invention] In the heat fusion method as described above, it is difficult to delicately control the temperature of the heating press tool such as a hot roll, the heating press time, the pressure, etc., and the thickness of the plastic coating is If it is thin, the plastic coating may be damaged due to heating or melting by solvents, such as tearing, and in the case of the above-mentioned coaxial cores, especially small diameter coaxial cores, this insulating layer may be crushed.
There are disadvantages in that not only the required electrical characteristics cannot be obtained, but also the high dimensional accuracy required for connector connection cannot be achieved.

In addition, in bonding methods using adhesives, it is generally not easy to apply the adhesive uniformly over the entire length, although it varies somewhat depending on the adhesive application method. However, there are disadvantages such as the possibility that the liquid may not penetrate sufficiently, resulting in insufficiently bonded areas.

[Means to solve the problem]

The present invention has been made to solve the above-mentioned problems, and includes applying a thermoplastic resin adhesive that melts at a temperature lower than the melting temperature of the plastic coating on the wire core in advance, Adjacent cores are bonded by arranging the required number of these cores closely in parallel and heating them using a heating tool such as a heating roll while advancing this core group to melt the adhesive. This provides a method for integrating the two. The heating temperature is set to a temperature intermediate between the melting temperature of the adhesive and the melting temperature of the plastic coating.

[Effect]

In the manufacturing method of the present invention, since the adhesive is applied to each individual wire core, the adhesive can be applied uniformly.Moreover, when the adhesive-coated wire cores are closely arranged in parallel, There will be sufficient adhesive between the hearts. In addition, since the melting temperature of the adhesive is lower than that of the plastic coating and the heating is performed at a temperature intermediate between the melting temperature of the adhesive and the melting temperature of the plastic coating, the adhesive melts and the bonding is sufficient. The plastic coating will not melt. Therefore, even if the plastic coating is thin, it will not suffer damage such as tearing. In addition, the heating temperature is low, and unlike pressure-sensitive adhesives, it can be bonded only by heating, so the pressure applied to the cable can be reduced. Since the layers do not touch, there is no risk of deterioration of electrical characteristics, and high dimensional accuracy required for connector connection can be achieved.

〔Example〕 Examples will be described below.

(Example ■) According to Fig. 1, a conductor 2 made of a 0.4 mm annealed copper wire is used, and a 0.3 mm thick plastic coating (insulation F) 3 made of polyvinyl chloride is coated on the conductor 2. A wire core 1 was prepared by applying an adhesive. The adhesive used here is
For example, vinyl chloride with a vinyl acetate content of 20-30%
A vinyl acetate copolymer solvent-borne adhesive was applied.

While arranging 30 wire cores 1 coated with adhesive as described above in close contact with each other in parallel and advancing the adhesive, the adhesive on the wire cores is heated and melted from above and below using, for example, a conventional heating roll 9 as shown in cross section in FIG. Then, adjacent wire cores were joined and integrated to produce a ribbon electric wire as shown in FIG. The melting temperature of the above-mentioned adhesive used here was about 100°C, and the melting temperature of the plastic coating was about 150°C, so the temperature of the heating roll was set at about 130°C between these. Note that it is desirable to coat the heating roll with fluororesin or the like so that the adhesive does not stick to it.

(Example ■) Further, according to FIG. 2, an insulating layer 6 made of foamed polyethylene with a thickness of about 0.3 mm is provided on a conductor 5 with a thickness of 0.2 mm, and a shielding layer 7 made of a copper wire braid and a .2mm
A coaxial core having a plastic coating (outer coating) 8 made of H-thick polyvinyl chloride is coated with adhesive in the same manner as in Example 1 to form a wire core 4, and 30 of these cores 4 are arranged in parallel. A ribbon electric wire as shown in FIG. 2 was manufactured by placing the wire in close contact with the wire and heating in the same manner.

In any of the above examples, the plastic coating (insulating layer) 3 in Example I and the plastic coating (outer coating) 8 in Example H were found to have no damage such as tearing, and adjacent wire cores were not damaged. A sufficient bond was obtained between the two. Furthermore, the electrical properties of the insulating layer 6 made of foamed polyethylene in Example (2) were measured and it was found that there was no abnormality at all. Additionally, the dimensional accuracy required for connector connection was achieved without any problems.

〔Effect of the invention〕

According to the manufacturing method of the present invention, adhesive is applied to each wire core in advance, and the required number of such wire cores are closely arranged in parallel. Since an adhesive is present and the adhesive is melted by heating in this state, uniform and sufficient bonding between adjacent wire cores can be obtained. Moreover, when heated, only the adhesive melts, and the plastic coating does not, so even if the plastic coating is thin, it will not be damaged by tearing.
In addition, even if there is an insulator inside that is prone to breakage, such as foamed polyethylene, the pressure applied to the cable can be reduced, so there is no risk of the cable touching, and in the case of cores with important electrical properties such as coaxial cores. The manufacturing method of the present invention is particularly effective for this purpose. Furthermore, the dimensional accuracy required for connector connection can be easily achieved.

[Brief explanation of drawings]

Figure 1 is a cross-sectional view of a ribbon wire when the wire core is made of an insulated conductor, Figure 2 is a cross-sectional view of a ribbon wire when the wire core is a coaxial core, and Figure 3 is a state in which the wire core group is sandwiched from above and below. FIG. 3 is a cross-sectional view of the heating roll. 1.4: Wire core, 2,5: Conductor, 3 Niblast coating (
insulation layer), 8-niblastic coating (outer coating). Figure 1 Figure 2 Figure 3

Claims (1)

[Claims] 1. In a ribbon wire manufacturing method in which a plurality of plastic-covered wire cores are arranged in parallel and adjacent wire cores are joined and integrated, a thermoplastic resin adhesive having a lower melting temperature than the plastic coating is bonded onto the wire core. After applying the adhesive, a plurality of the wire cores are closely arranged in parallel and advanced while heating to a temperature between the melting temperature of the plastic coating and the melting temperature of the adhesive to join adjacent wire cores to each other. A method for manufacturing a ribbon electric wire, characterized by: