JPH04253110A - Cable and its manufacturing method - Google Patents

Abstract

PURPOSE:To manufacture a cable insulated with vinyl chloride resin without staining and spoiling he work fields for manufacturing and wiring process, without causing industrial hygiene troubles due to scattering powders, and without producing inferior products and stopping of the working due to choking of niples and dies in an extrusion coating process. CONSTITUTION:Vinyl chloride resin so crosslinked as to contain at least 10wt.% of a tetrahydrofuran-insoluble component is used as an insulator for a core wire and extrusions having at least 50mum height or grooves having at least 50mum depth are formed on the outer surface of the insulator. Or vinyl chloride resin so crosslinkded as to contain at least 10wt.% of tetrahydrofuran-insoluble component is used as the insulator of a core wire and the roughness of the outer surface of the insulator is made to be at least 5mum.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cable and a method for manufacturing the same, and more particularly to a cable that prevents fusion of an insulator made of vinyl chloride resin and a sheath, and a method for manufacturing the same.

0002

[Prior Art] Cables using vinyl chloride resin as an insulator and an insulating sheath are widely used because they have many advantages. At this time, the insulator and sheath tend to fuse together, resulting in reduced flexibility and mobility, difficulty in terminal processing, and cable undulations. Conventionally, as a method of preventing fusion between the insulator and the sheath, a lubricant such as talc or mica powder is sprinkled on the surface of the insulator before extrusion coating the sheath.

0003

However, in conventional cables in which fusion of the insulator and sheath is prevented by the above-described method, problems arise during manufacturing and use due to lubricant powder. First, the lubricant powder may scatter during the manufacturing process and wiring work, contaminating the surrounding area, and may harm the health of workers if inhaled. Second, lubricant powder clogs nipples and dies during the extrusion process, leading to defective products and work stoppages.

[0004] In addition, since a step of dispersing a lubricant is added, manufacturing costs also increase. Therefore, the object of the invention is to
It is an object of the present invention to realize a vinyl chloride resin insulated cable and a method for manufacturing the same, which are free from contamination of manufacturing and wiring work sites and occupational health problems caused by powder scattering.

A further object of the present invention is to realize a vinyl chloride resin insulated cable and a method for manufacturing the same, which does not cause defective products or work stoppages due to clogging of nipples or dies during the extrusion coating process.

[0006]

[Means for Solving the Problems] The present invention eliminates pollution of manufacturing and wiring work sites and occupational health problems due to powder scattering, and eliminates the occurrence of defective products due to clogging of nipples and dies during the extrusion coating process. In order to realize a vinyl chloride resin insulated cable and its manufacturing method that does not cause work stoppages, a vinyl chloride resin cross-linked to contain at least 10% by weight of tetrahydrofuran-insoluble components is used as the insulator of the core wire, and the outer surface of the insulator is Protrusions with a height of at least 50 μm or grooves with a depth of at least 50 μm were provided.

[0007] The present invention also eliminates contamination of manufacturing and wiring work sites and occupational health problems due to powder scattering, and eliminates the occurrence of defective products or work stoppages due to clogging of nipples or dies in the extrusion coating process. In order to realize a vinyl resin insulated cable and its manufacturing method, at least 10% by weight of a tetrahydrofuran insoluble component is used as an insulator of an insulated core wire.
A cross-linked vinyl chloride resin was used so that the outer surface of the insulator had a surface roughness of 5 μm or more. In the present invention, surface roughness is expressed as a value measured by a method specified in JIS-B-0651.

[0008] Uncrosslinked vinyl chloride dissolves in tetrahydrofuran (hereinafter referred to as THF), but when vinyl chloride is polymerized in the presence of a polyfunctional monomer, the vinyl chloride resin is crosslinked, with a proportion depending on the degree of crosslinking. THF-insoluble components are now included. If the THF-insoluble component contained in the vinyl chloride resin (hereinafter referred to as PVC) is less than 10% by weight, the effects of the present invention cannot be obtained even if predetermined protrusions or grooves are provided. Practically, the upper limit of the content of THF-insoluble components is 70% by weight, and if it is larger than this, it will be difficult to melt during extrusion molding. The degree of polymerization of uncrosslinked PVC is not particularly limited, but the average degree of polymerization is usually in the range of 700 to 4,000. By using PVC with a relatively high average degree of polymerization (for example, 1000 or more), it is easier to obtain a large surface roughness with the same ratio of THF-insoluble components.

[0009] PVC containing THF-insoluble components in a predetermined ratio
may be prepared by blending PVC with a higher proportion of THF-insoluble components and PVC with a lower proportion. For surface roughness of 5 μm or more, the ratio of THF-insoluble components is 20
It can also be easily obtained by blending PVC with a higher weight % and lower PVC so that the THF-insoluble component is 10 weight % or more. Alternatively, a predetermined surface roughness may be obtained by mixing an inorganic or organic solid powder, such as calcium carbonate or vulcanized rubber powder, into the PVC insulation composition.

The outer surface of the insulator has a surface roughness of 5 μm or more, or is provided with projections having a height of at least 50 μm or grooves having a depth of at least 50 μm. Protrusions with a surface roughness of less than 5 μm and a height of at least 50 μm or at least 50 μm
If a groove with a depth of m is not provided, TH
Even if PVC containing a predetermined proportion of F-insoluble components is used, the effects of the present invention cannot be obtained. In particular, when the extrusion temperature of the PVC sheath is 200° C. or higher, fusion with the insulator occurs. It is preferable that the protrusions or grooves be provided on the outer surface of the insulator at as fine an interval as possible within 1 mm, particularly at an interval of 500 μm or less. However, the spacing must not be less than 10 μm. The intervals between the protrusions or grooves may be non-uniform, but are preferably uniform.

[0011]

[Function] In the cable of the present invention, the insulator is made of cross-linked vinyl chloride resin containing at least 10% by weight of THF-insoluble components, and the outer surface of the insulator has a surface roughness of 5 μm or more, or on the surface, at least 50
Since the protrusions having a height of .mu.m or the grooves having a depth of at least 50 .mu.m are provided, fusion between the insulator and the PVC sheath does not occur even if no lubricant powder is attached.

According to the cable manufacturing method of the present invention, TH
The insulator is made of a cross-linked vinyl chloride resin containing at least 10% by weight of F-insoluble components, and the outer surface of the insulator is provided with protrusions having a height of at least 50 μm or grooves having a depth of at least 50 μm; Alternatively, by making the outer surface of the insulator have a surface roughness of 5 μm or more, when extrusion coating the PVC sheath, it is possible to
Fusion with the VC sheath is prevented. In particular, even when the extrusion temperature of the PVC sheath is 200° C. or higher, no fusion occurs with the insulator.

[0013] Examples are shown below to provide a more detailed explanation of the present invention.

[0014]

Embodiment 1 An example of a captire cable according to the present invention is shown in FIG. As shown in Figure 1(A), the cable is
A conductor 1 with a cross-sectional area of 2 mm2 is made by twisting conductor wires together,
Three core wires 3 covered with a vinyl chloride resin insulator 2 with a thickness of 0.8 mm are twisted together to form a wire core 3a shown in FIG. 1(B), which is covered with a vinyl chloride resin sheath with a thickness of 1.8 mm. 4
It is coated with The outer surface of the insulator 2 has a protrusion 2a having a triangular cross section with a height of 50 μm and a base of 50 μm, which is continuous in the axial direction of the core wire. The protrusions 2a have a circumferential interval of 450 μm and a number of 20. The vinyl chloride resin constituting the insulator 2 is crosslinked polyvinyl chloride containing 10% by weight of THF-insoluble matter, and the average degree of polymerization of the vinyl chloride resin constituting the sheath 4 is 2,500.

[0015] This captire cable was manufactured as follows. Conductor 1 is made by twisting 37 conductor wires each having a diameter of 0.26 mm. 50% by weight of polyvinyl chloride with an average degree of polymerization of 1300 crosslinked to such an extent that it contains 20% by weight of THF-insoluble matter, and 50% by weight of the same uncrosslinked polyvinyl chloride.
Insulator 2 having the composition shown in Table 1 is prepared by further adding additives to the blend (referred to as I) with 0% by weight.

[0016] Table 1

When covering the conductor 1 with the insulator 2, a groove is provided on the outer periphery of the die opening so that a protrusion 2a having a height of 50 μm and a width of 50 μm is formed. Three core wires 3 each having a conductor 1 covered with an insulator 2 are twisted together to form a wire core 3a, and a sheath 4 is formed by extrusion coating vinyl chloride resin onto the wire core 3a using a 40 mm extruder. The temperatures of each part of the extruder are 160°C in the first cylinder, 200°C in the second cylinder, 200°C in the third cylinder, 200°C in the crosshead section, and 220°C in the die. At this time, the temperature of the extruded resin is 205°C.

The sheath of the cable obtained as described above was stripped over a length of 10 m, and the ease of stripping and the fusion between the insulator and the sheath were examined. In the cable of Example 1, no fusion was observed between the core wire insulator and the sheath, and the sheath releasability was good.

[0019]

Embodiment 2 Another example of the captire cable according to the present invention is shown in FIG. The conductor 1 and sheath 4 are the same as in the first embodiment. The outer surface of the insulator 2 was provided with a groove 2b continuous in the axial direction of the core wire and having a triangular cross section with a depth of 50 μm and a width of 50 μm. The number of grooves 2b is 20, and the interval on the circumference is 4.
It is 50 μm. Three core wires 3 having a conductor 1 covered with an insulator 2 were twisted together to form a wire core.

[0020] In manufacturing this captire cable, when covering the conductor 1 with the insulator 2, a triangular protrusion is provided on the outer periphery of the opening of the die, and a groove 2b with a depth of 50 μm and a width of 50 μm is formed. The same procedure as in Example 1 was carried out except for the following. In the same manner as in Example 1, the ease of peeling off the sheath and the fusion of the insulator and sheath were examined. In the cable of Example 2, no fusion was observed between the core wire insulator and the sheath, and the sheath releasability was good.

The insulator 2 is composed of two layers, an inner layer and an outer layer, and the inner layer is made of uncrosslinked vinyl chloride resin that does not contain THF-insoluble matter, and only the outer layer (about 0.2 μm thick) is made of vinyl chloride resin. The same results could be obtained using a crosslinked vinyl chloride resin containing a certain amount of THF-insoluble matter.

[0022]

[Embodiment 3] Third embodiment of the captire cable according to the present invention
An example is shown in Figure 3. The same conductor 1 as in Example 1 was used with a thickness of 0.
Three core wires 32 covered with an 8 mm crosslinked vinyl chloride resin insulator 31 were twisted together to form a wire core 32a, which was then covered with the same vinyl chloride resin sheath 4 as in Example 1. The insulator 31 is made of cross-linked polyvinyl chloride (referred to as II) obtained by cross-linking uncross-linked polyvinyl chloride with an average degree of polymerization of 1300 to an extent containing 30% by weight of THF-insoluble matter, with additives shown in Table 2. It has a composition.

[0023]Table 2

The outer surface of the insulator 31 conforms to JIS-B-06
The surface roughness measured by the method specified in No. 51 is 10 μm.

[0025] In the same manner as in Example 1, the ease of peeling off the sheath and the fusion of the insulator and sheath were examined. In the cable of Example 3, no fusion was observed between the core wire insulator and the sheath, and the sheath releasability was good.

[0026]

[Embodiment 4] The conductor 1 and sheath 4 are the same as in Embodiment 3, but as shown in FIG. 4, the insulator 41 is divided into two layers, an inner layer 41a and an outer layer 41b, and only the outer layer 41b is cross-linked. Vinyl chloride resin was used. That is, the inner layer 41a with a thickness of 0.6 mm is made of uncrosslinked vinyl chloride resin that does not contain THF-insoluble matter, and the outer layer 41 with a thickness of 0.2 mm is used.
The same crosslinked vinyl chloride resin as in Example 3 was used for b.

The production of this captire cable is the same as in Example 3, except that when covering the conductor 1 with the insulator 41, two layers, the inner layer 41a and the outer layer 41b, are extruded.

[0028] In the same manner as in Example 1, the ease of peeling off the sheath and the fusion of the insulator and sheath were examined. No fusion was observed between the core wire insulator and the sheath, and the sheath removability was the same as in Example 3.

[0029]

[Example 5] As the insulator 31 in FIG. 3, instead of a crosslinked vinyl chloride resin containing 30% by weight of THF-insoluble matter,
THF obtained by blending 50% by weight of crosslinked vinyl chloride resin containing 20% by weight of THF-insoluble content, same as used in Example 1, and 50% by weight of uncrosslinked polyvinyl chloride (average degree of polymerization 1300). A crosslinked vinyl chloride resin containing 10% by weight of insoluble matter was used. The surface roughness of the insulator 31 in this case was approximately 5 μm.

[0030] In the same manner as in Example 1, the ease of peeling off the sheath and the fusion between the insulator and the sheath were examined. No fusion was observed between the insulator of the insulated core wire and the sheath, and the sheath removability was good.

[0031]

[Comparative Example] As the insulator 31 in FIG. 3, instead of the crosslinked vinyl chloride resin blended to contain 10% by weight of THF-insoluble matter, 20% by weight of crosslinked vinyl chloride resin containing 20% by weight of THF-insoluble matter, A crosslinked vinyl chloride resin containing 4% by weight of THF-insoluble matter, which was obtained by blending 80% by weight of uncrosslinked polyvinyl chloride (average degree of polymerization 1300), was used. In this case as well, the surface roughness of the insulator 31 is approximately 5μ.
It was m.

[0032] In the same manner as in Example 1, the ease of peeling off the sheath and the fusion of the insulator and sheath were examined. Fusion between the insulator and sheath is observed throughout the cable length,
It was difficult to remove the sheath.

From the above Examples and Comparative Examples, it is clear that the vinyl chloride resin insulated cable according to the present invention is directly coated with PV on the insulator.
Even when covered with a C-sheath, fusion does not occur between the insulator and the sheath, and by the cable manufacturing method of the present invention, it is possible to manufacture a vinyl chloride resin insulated cable that does not cause fusion between the insulator and the sheath. it is obvious.

[0034]

Effects of the Invention: The vinyl chloride resin insulated cable of the present invention does not cause fusion between the insulator and the sheath even if lubricant powder is not sprinkled on the surface of the core wire, so it is possible to prevent the lubricant powder from being applied at manufacturing sites and wiring work sites. It does not cause any occupational health problems due to staining or powder scattering.

Furthermore, according to the method for manufacturing a vinyl chloride resin insulated cable of the present invention, not only is there no contamination caused by lubricant powder at manufacturing and wiring work sites, nor occupational health problems caused by powder scattering, but there is also no problem in the extrusion coating process. It is possible to manufacture a vinyl chloride resin insulated cable without fusion between the insulator and sheath, without causing defective products or work stoppages due to clogging of nipples or dies.

[Brief explanation of the drawing]

FIG. 1(A) is a sectional view showing an embodiment of a captire cable according to the present invention, and FIG. 1(B) is a sectional view of a wire core in the same embodiment.

FIG. 2 is a sectional view showing another embodiment of the captire cable according to the invention.

FIG. 3 is a sectional view showing a third embodiment of the captire cable according to the present invention.

FIG. 4 is a sectional view showing still another embodiment of the captire cable according to the present invention.

[Explanation of symbols]

1 conductor 2 insulator
2a Protrusion 2b Groove 3 Core wire 3a Core wire
4 Sheath 31 Insulator

Claims (4)

[Claims] 1. A cable in which an insulator and an insulating sheath are made of vinyl chloride resin, wherein the insulator comprises:
It is composed of a crosslinked vinyl chloride resin containing at least 10% by weight of a tetrahydrofuran-insoluble component, and is characterized by having projections having a height of at least 50 μm or grooves having a depth of at least 50 μm on the outer surface. Yes, cable. 2. A cable in which an insulator and an insulating sheath are made of vinyl chloride resin, the insulator comprising:
A cable comprising a vinyl chloride resin crosslinked to contain at least 10% by weight of a tetrahydrofuran-insoluble component, and having an outer surface with a surface roughness of 5 μm or more. 3. A method for manufacturing a cable, in which the outer periphery of the conductor is coated with a vinyl chloride resin insulator, and the outer periphery of the core wire is coated with vinyl chloride resin by extrusion to form an insulating sheath,
The insulator is composed of a crosslinked vinyl chloride resin containing at least 10% by weight of a tetrahydrofuran-insoluble component, and the outer surface of the insulator has protrusions having a height of at least 50 μm or a depth of at least 50 μm. A method for manufacturing a cable, characterized in that a groove is provided and the extrusion coating is applied to the outer surface of the insulator provided with the protrusion or groove. 4. A method for manufacturing a cable, in which the outer periphery of the conductor is coated with a vinyl chloride resin insulator, and the outer periphery of the core wire is coated with vinyl chloride resin by extrusion to form an insulating sheath,
The insulator is made of a vinyl chloride resin crosslinked to an extent containing at least 10% by weight of a tetrahydrofuran-insoluble component,
A method of manufacturing a cable, characterized in that the outer surface of the cable is configured to have a surface roughness of at least 5 μm, and the outer surface of the insulator is coated with the extrusion coating.