JP5886229B2 - cable - Google Patents

Description

  The present invention relates to a cable such as a vinyl insulated vinyl sheath cable.

For example, as shown in FIG. 7, a vinyl-insulated vinyl sheath cable is formed by twisting a plurality of insulated wires 1 in which a conductor 1a is insulation-coated with polyvinyl chloride 1b via an intervening 2, and a press-wrapping tape such as a nonwoven fabric around its outer periphery. In general, after winding 3, the outer periphery of the sheath is extruded and coated with a polyvinyl chloride sheath 4 (see Patent Document 1, FIG. 3, and FIG. 4).
The press-winding tape 3 finishes the appearance of the cable P ′ in a round shape, and the sheath (1b) of the insulating core wire 1 and the sheath 4 are made of the same kind of resin and are compatible. Wrapped to prevent welding.

A cable such as a vinyl-insulated vinyl sheath cable P ′ having this configuration requires the stripping and removal of the sheath 4 and the presser winding tape 3 when exposing the insulation core wire 1 at the end of construction, and its workability is poor. There was a problem. In recent years, reduction of manufacturing cost has been demanded.
Under such circumstances, there has been proposed a cable that employs a cross-linked polyethylene blend for the interposition 2 and omits the press-wound tape 3 to reduce the cost (Patent Document 1, Claim 1). FIG. 1).

Japanese Patent No. 3414576

The vinyl-insulated vinyl sheath cable that employs a cross-linked polyethylene blend for the interposition 2 is a cross-linked polyethylene shredded article 100 as a cross-linked polyethylene blend in order to prevent welding (adhesion) between the insulation core wire 1 made of vinyl chloride and the sheath 4. Adopting 15 to 30 parts by weight of LDPE, 5 to 10 parts by weight of foaming agent, and 25 parts by weight or more of the total composition other than the cross-linked polyethylene shredded product is used with respect to parts by weight ( Patent Document 1 (see claim 1)).
This blending is complicated and requires an additional step of extruding the intervening crosslinked polyethylene blend, resulting in a high-cost cable.

  An object of the present invention is to provide a cable in which the covering tape 3 and the sheath are made of the same kind of resin that can omit the press-winding tape 3 and does not deteriorate the stripping property of the sheath under the actual condition. .

  In the cable in which the sheath 1b and the sheath 4 of the insulation core wire 1 such as the vinyl insulation vinyl sheath cable P ′ are made of the same kind of resin, the intervening is made of a string-like or thread-like material, and a plurality of insulated wires are more than a certain filling ratio. If the wire is twisted together with the intervening wire, the interstitial wire penetrates between the insulation cores over the entire length of the cable, and the insulation covering area of the insulation wire exposed on the outer peripheral surface of the twisted wire (core) is extremely small. We thought that if the sheath was extruded and coated on the outer peripheral surface of the core, the stripping property of the sheath could be secured, and when the sheath was extruded and coated on the core without the press-wound tape, the strip was removed. A cable that does not degrade is obtained.

  The present invention has been obtained by experiments based on the idea. Specifically, a plurality of insulating core wires are twisted together via an intervening, a press-wrapping tape is omitted, and a sheath is provided on the outer periphery of the sheath. A cable provided directly, wherein the insulation coating of the insulation core wire and the sheath are made of the same type of resin, the interposition is made of a material that is not compatible with the resin, and the sheath is extruded to form the insulation core The structure is not welded to the wire insulation coating.

Various resins conventionally used can be adopted as the insulation coating and sheath resin of the insulation core, but if polyvinyl chloride is adopted, a vinyl insulated vinyl sheath cable is obtained.
The material having no compatibility with the intervening resin may be appropriately selected according to the resin. For example, resins such as polypropylene, polyester, nylon, and jute, paper, and the like are conceivable. The shape may be a string, a thread, a tape, or the like.

Further, the filling ratio of the interstitial is relative to the gap cross-sectional area between the insulating core wires surrounded by the outer peripheral surface (external peripheral surface) of the stranded wire twisted with the insulating core wires and the outer surface (exposed surface) of the stranded wire. This is the amount of intervention, for example, the denier number per 1 mm ^{2 of} the gap cross-sectional area. Moreover, 1 denier (De) means the thickness of the thread | yarn which becomes 1g at 9000m.
Therefore, the above-mentioned “configuration in which the sheath is extruded and not welded to the insulation coating of the insulation core wire” is considered to increase the intervening filling amount compared to the conventional case, and this intervening filling amount (filling ratio). By increasing the height, the outer peripheral surface of the insulated core wire is buried in the outer peripheral surface of the interposition, making it more difficult for the insulating core wire and the sheath to come into contact with each other, preventing welding between the insulating core wire and the sheath. Is done. In the case of a thread or string, preferably, the intervening filling rate between the insulating cores 1 is 3390 denier / mm ² or more.

In the cable having this configuration, an insulation made of a material that is incompatible with the resin forming the both coatings enters between the insulating core and the sheath to isolate the two. For this reason, the insulation coating area of the insulation core wire exposed on the outer peripheral surface of the twisted core is extremely small, and the insulation coating of the insulation core wire and the sheath are extremely less in contact with each other, making it difficult to weld. Therefore, there is no problem in stripping the sheath during construction work. Further, during the construction, the work of removing the presser winding tape 3 is not necessary, and the waste material is reduced.
If the above extrusion molding is a pipe (tube) extrusion , the sheath , which is a pipe extrusion molded product, is less likely to be pressed against the outer peripheral surface of the core. As a result, it becomes difficult to weld, so that there is no more hindrance to peeling off the sheath in construction work.
Further, when the cable is manufactured, the winding process of the presser winding tape is eliminated, so that the operation of the twisting machine for replacing the presser winding tape is eliminated and continuous operation becomes possible.

  As described above, the present invention omits the press-wound tape and employs a material made of a string-like or thread-like material that is not compatible with an insulation coating or a sheath such as polyvinyl chloride resin, among conventional interventions. In addition, since the sheath is formed by extrusion coating, a cable made of the same kind of resin as the sheath of the insulation core wire such as a vinyl insulated vinyl sheath cable can be manufactured by the same manufacturing process as before, and the sheath is peeled off. It becomes a cable that does not deteriorate the handleability.

1 shows an embodiment of a vinyl-insulated vinyl sheathed cable according to the present invention, (a) is a cross-sectional view, and (b) is a cut front view with a part of the sheath removed. Sectional view of the other embodiment Sectional view of the other embodiment Sectional view of the other embodiment Sectional view of the other embodiment Sectional view of the other embodiment Cross section of conventional example

  Each embodiment of the present invention is shown in FIG. 1 to FIG. 6, and each embodiment is twisted to the pair of insulating core wires 1 shown in FIG. CVV cable (control vinyl insulated vinyl sheath cable for control) P (hereinafter simply referred to as “cable P”) in which the sheath 4 is extrusion-molded and covered with a pipe.

  The insulation core wire 1 is obtained by insulatingly covering a conductor 1a with polyvinyl chloride 1b as in the prior art, and the sheath 4 is also made of polyvinyl chloride. The polyvinyl chloride resin of the insulation coating (insulator) 1b is composed of, for example, 35 parts by mass of calcium carbonate and 50 parts by mass of a plasticizer with respect to 100 parts by mass of the polyvinyl chloride resin. The vinyl chloride resin contains 40 parts by mass of calcium carbonate and 50 parts by mass of a plasticizer with respect to 100 parts by mass of the polyvinyl chloride resin.

FIG. 1 shows a cable P ₁ with two insulated cores 1, FIG. 2 with three cables, FIG. 3 with four cables, FIG. 4 with five cables, FIG. 5 with six cables, and FIG. To P ₆ (generic symbol: P). In each of the embodiments, the intervening filling rate is increased as compared with the conventional example. 2 to 5, an intervening string can be employed in the central gap portion surrounded by the insulating core wire 1, and in FIG. 6, the central insulating core wire 1 and the outer peripheral insulating core wire 1. An intervening string can be employed in the space between the two. Examples of the cable modes (embodiments) shown in FIG. 1, FIG. 2, FIG. 3, and FIG. In addition, the comparative filling example of the cable mode shown in FIGS.

  In this example and the comparative example, the insulation coating 1b and the sheath 4 employ a polyvinyl chloride resin having the above composition, and the interposer 12 employs a polypropylene yarn (string). The extrusion temperature of the sheath 4 is 185 ° C., the linear velocity is 50 to 50- Pipe extrusion coating was performed at 100 m / min.

In each of these Examples and Comparative Examples, the following “peelability test” was performed, and the results are shown in Table 1.
"Peelability test"
A cut is made with a cutter knife so as to divide the sheath 4 in half, and the sheath 4 is peeled off in the length direction of the cable P, and the inner surface (peeling surface) of the sheath 4 after peeling is visually observed. When the resin of the insulation coating 1b and the sheath 4 are welded and bonded, and the trace of destruction is seen on the peeled surface by peeling off, it is judged as “Fail”, and there is no evidence of destruction. The case was “pass” and “welding: none”.

In this test, each example increased the amount of the intervening 12 compared to the conventional (comparative example) (because the filling ratio was increased), so that the circular diameter of the outer peripheral surface of the intervening 12 is the outer periphery of the stranded wire of the insulating core wire 1. The gap s shown in FIG. 1B is generated between the outer peripheral surface of the interposer 12 and the outer peripheral surface of the stranded wire of the insulating core wire 1, and the outer peripheral surface of the intervening 12 is also visually observed. It was confirmed that the outer peripheral surface of the stranded wire of the insulation core wire 1 was buried inside. For this reason, as shown in Table 1, the insulation core wire 1 and the sheath 4 are difficult to contact and the insulation core wire 1 and the sheath 4 are prevented from being welded (welding between the insulation coating 1b and the sheath 4: None. ).
On the other hand, in each comparative example, since the amount of the intervening 12 is the same as the conventional one, the circular diameter of the outer peripheral surface of the intervening 12 is substantially the same as the circular diameter of the outer peripheral surface of the stranded wire of the insulating core wire 1. The gap s was hardly generated between the outer peripheral surface of the insulating core wire 1 and the outer peripheral surface of the stranded wire of the insulating core wire 1, and welding between the insulating core wire 1 and the sheath 4 was observed (welding between the insulating coating 1b and the sheath 4). : Yes).

Specifically, in the two-core embodiment shown in FIG. 1, the intervening filling rate between the insulation cores 1 is 3807 denier / mm ² compared to the conventional: 2928 denier / mm ² . However, there is no hindrance to the stripping of the sheath 4 (welding between the insulating coating 1b and the sheath 4: none). Further, in the three-core embodiment shown in FIG. 2, when the intervening filling rate is 4408 denier / mm ² compared to 2755 denier / mm ² , there is no problem in peeling off the sheath 4. (Welding of insulating coating 1b and sheath 4: none). Further, in the four-core embodiment shown in FIG. 3, when the intervening filling rate is 3390 denier / mm ² compared to 2825 denier / mm ² , there is no problem in peeling off the sheath 4. (Welding of insulating coating 1b and sheath 4: none).

From the test results of Table 1, the lower limit of the interposition filling rate of “welding: none” is “3390”, and if the interposition filling rate is 3390 denier / mm ² or more, it will hinder stripping of the sheath 4. It is possible that no occurs.
Moreover, in each Example of the structure shown in Table 1, when the pipe type extrusion coating was performed under the conditions of the extrusion temperature of the sheath 4: 200 ° C. and the linear velocity: 50-100 m / min, the extrusion temperature was 185 ° C. Similarly, there was no hindrance to stripping of the sheath 4 (welding between the insulation coating 1b and the sheath 4: none).

  From the above, it is considered that the factor related to the peelability is the interposition filling ratio between the sheath 4 and the insulating core wire 1, and the sheath 4 and the insulating core wire 1 are increased by increasing the filling ratio as compared with the conventional case. It can be understood that it is possible to prevent welding and the deterioration of the peelability.

In the above test, the case where the insulation coating 1b and the sheath 4 were not welded was defined as “welding: no” and “no problem in stripping”, but even in a slight welding state, There is no problem in stripping. Therefore, the “configuration in which the sheath is extruded and not welded to the insulating coating of the insulating core wire” in the claims includes not only the configuration in which the sheath and the insulating coating are not welded at all, but also the sheath 4 It includes a slight welded state as long as it does not hinder stripping.
Needless to say, the present invention is not limited to the CVV cable according to the embodiment, and can be applied to various cables. Further, the extrusion coating of the sheath 4 is not limited to pipe extrusion molding, and other molding means can be adopted as long as the effects of the present invention are exhibited.

DESCRIPTION OF SYMBOLS 1 Insulation core wire 1a Insulation core wire conductor 1b Insulation core wire polyvinyl chloride insulation coating 2, 12 Interposition 4 Polyvinyl chloride sheath P ′, P ₁ , P ₂ , P ₃ , P ₄ , P ₅ , P ₆ vinyl insulated vinyl sheath cable

Claims (1)

A cable (P) in which a plurality of insulated core wires (1) are twisted together via an interposition (12), a press-wound tape is omitted, and a sheath (4) is directly provided on the outer periphery thereof as an exterior, insulating coating of insulated wires (1) (1b) and the sheath (4) is made of polyvinyl chloride, made from the intervening (12) yarn or string of compatibility is not polypropylene yarn of the polyvinyl chloride, the The filling ratio of the interposition (12) between the insulating core wire (1) surrounded by the outer peripheral surface of the twisted wire obtained by twisting the insulating core wire (1) and the outer surface of the twisted wire is 3390 denier / mm ² or more. Thus, the outer peripheral surface of the insulation core wire (1) is buried in the outer peripheral surface of the interposition (12), and the sheath (4) is made of an extruded product of the pipe and the insulation core wire (1). A cable characterized by not being welded to the insulation coating (1b).

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