JPH02265108A - Flame proof cable and its manufacture - Google Patents

Abstract

PURPOSE:To keep high quality without air embracement by providing a separator sheath which is formed by extrusion inside a flame proof sheath. CONSTITUTION:A cable core 1, an aluminum laminating sheath 2, a separator sheath 3 formed by extrusion and a flame proof PVC sheath 4 are constitutional elements. The aluminum laminating sheath 2 serving as a water-barrier layers is provided as necessary for adapting such atmosphere as underground wiring. In such a manner that the separator sheath 3 formed by extrusion is provided inside the flame proof sheath 4, there is no air embracement and no crater inside a sheath to improve quality.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a flame-retardant cable with a separator layer that can shorten the manufacturing process and a method for manufacturing the same. Three types of cables have been put into practical use: (1) simply installing a flame-retardant (1) VC (polyvinyl chloride, the same hereinafter) sheath over the cable core; (2)
For use in humid places such as inside caves or underground, it consists of a double sheath consisting of a water-blocking layer such as aluminum tape and a Lamiho 1 sheath made of polyethylene, with a combustible PVC sheath on top. 6 (3) Those with a non-halogen polyethylene sheath that can suppress the generation of toxic scum and smoke in tunnels, underground malls, etc. 7 Of the above, in the case of cables with a flame-retardant PvC sheath, plasticizers in the PVC In order to prevent migration to the core side, a separator tape made of polyester tape, nylon tape, etc. is usually wound horizontally and interposed inside the PVC sheath.

Figure 4 shows a specific 1f of such a conventional flame-retardant cable.
It is a sectional view showing the I4 configuration, where 1 is the cable core 2 made of an aluminum laminate sheath, 3- is the separator tape mentioned above, and 4
Cables such as the one shown in FIG. 5, which has a flame-retardant PvC sheath, are usually manufactured by the process shown in FIG.

First, in step (a), the cable core 1 is sent out from the sending device 10, and the aluminum laminate sheath 2a is put into the molding machine 1.
1, the aluminum laminate tape is coated with polyethylene by extrusion using the crosshead 13 of the extruder 12 to obtain the aluminum laminate sheathed cable 2A, cooled in the cooling trough 14, taken up by the take-up machine 15, and then taken up by the take-up machine 15. The cable 2A with the aluminum laminate sheath is then transferred to the step (b), where the cable 2A with the aluminum laminate sheath is sent out from the sending machine 10-, and the separator tape 3'' is wound with the separator tie 1 and 17. As attached cable 3-A,
This is taken up by a take-up machine 15- and wound up by a wind-up machine 16-.

Next, the process is transferred to step (c), where the cable 3-A with the separator tape is sent out from the sending device 10'', and the extruder 1
A flame-retardant PVC sheath is extruded and coated with the crosshead 19 of No. 8, then cooled with a cooling trough 14-, taken up with a take-up machine 15'', and wound up with a winding machine 16''.
Get a fire-powered PVC cable.

PROBLEM TO BE SOLVED BY THE INVENTION 1 As is clear from the explanation of the two layers, three steps of FIGS. 5(a), (b) and (cl) are required in conventional manufacturing.

In other words, there is a separator tape winding process, which takes a lot of time including moving and setup.
It is difficult to respond to requests for short delivery times.''-1 This results in high costs.

Furthermore, air is likely to be trapped in this separator tape winding process, and if this air is trapped, uneven avatars will occur on the inner surface of the extruded flame-retardant PVC sheath, resulting in poor appearance. Electrical properties such as withstand voltage may also deteriorate, which may impair reliability.In order to prevent sagging, it is necessary to increase the thickness of the PVC sheath, which may lead to material failure due to excessive adhesion.

The purpose of the present invention is to solve the problems of the conventional technology mentioned above, to reduce the number of steps by one, and to make it possible to respond to short delivery times, while being inexpensive overall and of high quality. 6 [Means for Solving the Problems] The present invention provides a separator sheath formed by extrusion inside a flame retardant sheath. In forming the separator sheath, a two-layer co-extrusion method is used.7 [Function] By extruding the separator sheath, there is no possibility of air entrapment, and high quality can be maintained. By forming the separator sheath by a two-layer co-extrusion method, it is possible to omit one manufacturing step, and a short delivery time can be achieved.

[Example] The present invention will be described below with reference to Examples. Fig. 1 is a sectional view showing a specific structure of a flame-retardant cable according to the present invention, where 1 is a cable core, 2 is an aluminum laminate. A sheath, 3 is a separator sheath formed by an extrusion method, and 4 is a combustion sheath. The aluminum laminate 1 to sheath 2, which serve as a water-blocking layer, are provided as necessary to cope with the atmosphere of underground wiring, etc., and may be omitted for indoor wiring.

Suitable materials for forming the separator sheath 3 include polyester, nylon, and fluororesin, which have the function of preventing plasticizer migration as described above, as well as facilitating sheath peeling. .

If the separator sheath 3 is formed by extrusion, there is no risk of entrapping air as in the case of conventional horizontal winding.
The thickness of the flame-retardant sheath 4 can be kept to the minimum required thickness, which allows for savings in terms of materials.

FIG. 2 is an explanatory diagram showing the manufacturing situation of the flame-retardant cable made of 4i1 as described above according to the present invention.

First, as shown in FIG. 2(a), the cable core 1 is sent out from the sending device 10, the aluminum laminate sheath 2a is formed and coated by the laminate tape forming machine 11, and then the cable core 1 is sent out from the sending out device 10, and the aluminum laminate sheath 2a is formed and coated with the laminate tape forming machine 11, and then the cable core 1 is sent out from the sending out device 10, and the aluminum laminate sheath 2a is formed and coated with the laminate tape forming machine 11. set outside ff1
The main extrusion fi is guided to the two-layer crosshead 21.
A two-layer separator sheath 3 is co-extruded on top of the polyethylene sheath extruded from 12. In this case, it is desirable to apply external pressure (0.1 to 0.3 kg/cJ) to improve adhesion. After extrusion, it is cooled in a cooling trough 14, and the product 3A with a separator sheath is taken out by a take-up a15 and wound up by a winder 16. The cable 3A with separator sheath is sent out from 10゛, and the flame-retardant PVC sheath 4 is sent out from one crosshead of the extruder 18.
The cable is extruded and coated, cooled in a cooling trough 14-, taken up by a take-up machine 15-, and wound up by a winding machine 16- to obtain a flame-retardant PVC sheathed cable 4A. According to such a manufacturing method, manufacturing can be performed in two steps (a) and (b), which is one less step than the conventional method, making it possible to significantly shorten the time. This is an example of specific extrusion conditions in the manufacturing method, or when extrusion was actually performed under these conditions,
We were able to manufacture high-quality cables with good dimensional accuracy.

Table 1 Note that when setting the temperature of the two-layer crosshead and tie, it is desirable to set the temperature within a range such that the MI (melt index) of both materials are approximately the same.

FIG. 3 is an explanatory diagram showing another manufacturing situation according to the present invention. In the seven solid line example showing the manufacturing situation by inner two-layer extrusion, in the step (a), a pull 2A with an aluminum laminate sheath is manufactured. and transfer this to step (b),
The above-mentioned aluminum laminar hose 1 to sheathed cable 2A are sent out from the sending device 10-, and the inner two-layer extrusion crosshead 2 is fed out.
2 and extruded by the sub-extruder 20 into flame-retardant PV extruded by the main extruder 18.
The separator sheath is guided inside the C sheath and two layers of separator sheath are simultaneously extruded inside the PVC sheath.

In this case, to improve adhesion, 10 to 20 cmH
(It is preferable to perform a vacuum of about [Effect 1 of the Invention As described above, according to the present invention, the following excellent effects can be exhibited.

(1) Since the separator sheet winding process can be completely omitted, the working time can be shortened and inexpensive cables can be supplied to the market with a short delivery time.

(2) Since there is no air entrapment in the manufacturing process and no avatars are generated on the inner surface of the sheath, quality can be improved and at the same time the sheath thickness can be minimized, eliminating cost increases due to the right person.

(3) If nylon is used as the separator sheath,
Is it effective as an ant-proof cable? You can save time.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of an embodiment of the flame-retardant cable according to the present invention;
2 and 3 are explanatory diagrams showing two embodiments of the V cable method according to the present invention, FIG. 4 is a sectional view showing the structure of a conventional flame-retardant cable, and FIG. 5 is a conventional manufacturing method. In the explanatory diagram, 8 shows the cable core, 2 Ni-laminated sheath, 3: Separator sheath, 4: PVC sheath, 2A Ni-aluminum laminate tape, 2A cable with Ni-aluminum laminate sheath, 3A fake partition sheath size cable, 4A: PVC Sheathed cable, 10.10-: Delivery device, 11: Laminating tape forming machine, 12.18: Extruder, 14.14-: Cooling trough, 15.15-: Taking machine, 16.16- Two-roller , 1: crosshead, 20: sub-extruder, 21: crosshead for outer two layer extrusion, 0 inch to the base 22: 1:1 head for inner layer extrusion.

Claims (2)

[Claims] (1) A flame-retardant cable comprising a separator sheath formed by extrusion inside a flame-retardant sheath; (2) A flame-retardant metal water-blocking layer is provided on the outer periphery of the cable core as necessary, a separator sheath is formed on it by a two-layer co-extrusion method, and a flame-retardant sheath is formed by extrusion in contact with the separator sheath. Method of manufacturing sex cables.