JPS5822842B2 - Plastic cable - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of manufacturing a plastic sheathed communication cable for shielding and moisture proofing purposes.

Recently, as a plastic sheathed communication cable for the purpose of shielding and moisture proofing, a laminate tape made by laminating a polyethylene film on one side of an aluminum tape is used as a shielding layer, and this is placed vertically on a group of communication cable cores to form a cable core. A so-called Grover sheath type communication cable is known, in which an outer plastic sheath is extruded and coated on the cable core.

When manufacturing the above-mentioned communication cable, it is necessary to prepare a shielding layer made by adhering a polyethylene film to a long aluminum tape slit to a predetermined width in advance.

However, when manufacturing the shielding tape, there are the following disadvantages.

That is, (1) the polyethylene film must be slit to a predetermined width in accordance with the aluminum tape width, and then the slit must be adhered to the aluminum tape, which increases the number of cable manufacturing steps.

(2) Slit loss occurs when slitting the polyethylene film to a predetermined width, which is uneconomical.

(3) When the slit polyethylene film is sequentially delivered to the running aluminum tape at a speed corresponding to the running speed of the aluminum tape and the two are bonded together, a new film is attached to the end of the preceding polyethylene film. It is extremely difficult to connect the starting end of the polyethylene film to be sent out.

This is because polyethylene film easily generates static electricity, so a known storage and supply device (accumulator) cannot be used.

This invention was invented to advantageously eliminate the above-mentioned disadvantages, and it is possible to create a glover sheath type communication cable without using a laminated tape made by adhering an inner layer of plastic such as polyethylene to an aluminum tape in advance. An object of the present invention is to provide a method for manufacturing a communication cable that can be manufactured.

Next, the present invention will be explained in detail using illustrated examples.

FIG. 1 shows an example of the present invention, in which a core group 1 which has been twisted together and further subjected to pressure winding, etc. as necessary, and an aluminum tape 3 fed from a reel 2 are vertically attached and formed. The aluminum tape 3 is placed vertically around the cable group 1 to form a cable core 5.

Next, this cable core 5 is introduced into an extrusion molding machine 6, and an inner layer plastic having a thickness of about 0.02 to 0.1 mm is extruded onto the cable core, and an inner layer plastic having a thickness of about 0.5 to 5 mm is further coated on top of this by extrusion.
．． A plastic sheathed communication cable 9 is constructed by extrusion coating an outer layer plastic 8 of 0 mm.

After this cable 9 is cooled by a cooling device 10,
It is wound up by a winding device (not shown).

FIG. 2 shows an example of the crosshead section of an extrusion molding machine used in carrying out the present invention, in which two types of plastic extrusion channels are formed in one crosshead, and The crosshead is configured to be able to simultaneously extrude and coat the inner layer plastic I and the outer layer 1 [IK outer layer plastic 8] onto the cable core 5 from the machine.

In addition, as the inner layer plastic material, a material that has good heat fusion properties for both the aluminum tape and the outer layer plastic, such as ethylene-vinyl acetate copolymer, EAA, EEA,
Polyfunctional copolymers such as Ionomasurlyn A (trade name) are preferred, and polyethylene (including EVA copolymers), which are economical and have good physical and chemical properties, are preferred as the outer layer plastic material.

In the example of this invention, two types of plastic extrusion channels are formed in one crosshead, and the inner layer and outer layer plastic melted from the two extruders are simultaneously extruded and coated. Although the configuration is shown in b, alternatively, two conventional crossheads may be installed in series and the inner and outer plastic layers may be extruded and coated separately.

However, if the former crosshead is used, the outer plastic layer can be immediately extruded and coated on the outside while the inner plastic layer is in a molten state, so that the mutual heat-sealing effect is extremely good.

Furthermore, if necessary, an aluminum tape corrugation device may be provided between the reel 2 and the forming machine 4, and the aluminum tape may be corrugated before being vertically attached around the aluminum tape core group. Furthermore, if a synthetic resin tape with good heat fusion properties is continuously interposed in the lap part of the aluminum tape that is created when the aluminum tape is attached vertically around the core wire group, the lap part of the aluminum tape can be firmly attached. be able to.

This invention is constructed in such a way that a cable core consisting of a group of wires covered with aluminum tape longitudinally is coated with an inner layer of plastic and then an outer layer of plastic by extrusion molding, so that it is possible to manufacture a communication cable for the purpose of moisture proofing and shielding. In this case, it is not necessary to prepare a so-called laminate tape in which a thin plastic film is laminated on an aluminum tape in advance.1. Therefore, the cable manufacturing process can be streamlined, there is no production loss of the laminate tape, and the cable manufacturing cost can be significantly lowered.

Furthermore, since the inner layer plastic T is already extruded and coated on the outside of the aluminum tape longitudinally attached to the core group, this inner layer plastic completely covers the edges of the lap portion of the aluminum tape, so even if the outer layer plastic This has the effect that the aluminum tape will not be damaged even if moisture penetrates from the aluminum tape.

[Brief explanation of the drawing]

FIG. 1 is a schematic side view showing an example of the implementation status of this invention;
FIG. 2 is a longitudinal sectional side view showing a crosshead of an extrusion molding apparatus used in carrying out the present invention, and FIG. 3 is a longitudinal sectional side view of a cable manufactured by the present invention. In the figure, 1 is a cable core group, 3 is an aluminum tape, 4 is a vertical forming machine, 5 is a cable core, 6 is an extrusion molding device, 7 is an inner layer plastic, 8 is an outer layer plastic, 9 is a communication The cable 10 is a cooling device.

Claims (1)

[Claims] 1. A cable core 5 formed by longitudinally attaching aluminum tape 3 to a communication cable core group 1 is led to an extrusion coating device, and an inner layer plastic T and an outer layer plastic 8 are extrusion coated on the cable core. A manufacturing method for a plastic sheathed A-signal cable.