JP7221907B2 - Wires and cables - Google Patents

Description

The present invention relates to wires and cables.

BACKGROUND ART For example, a crosslinked polyethylene insulated vinyl sheath cable (hereinafter referred to as CV) is used as an indoor/outdoor wiring of a building, a distribution board, a power control board and the like. CVs are widely used as power cables because of their excellent electrical properties, light weight, and ease of handling.

For example, a CV as disclosed in Patent Document 1 has been developed.

JP-A-11-329101

The thicker the wire/cable, the harder it becomes and the more difficult it is to bend. Therefore, the allowable bending radius of the electric wire/cable is increased. Wires and cables with a large allowable bending radius require a large wiring space, which may make wiring in a narrow space difficult. In addition, if a rigid wire/cable is excessively bent, defects may occur at the bent portion, degrading the cable performance. Such a tendency becomes more conspicuous as the wire/cable becomes thicker and as the operating environment becomes colder.

SUMMARY OF THE INVENTION It is an object of the present invention to provide wires and cables with improved flexibility and low temperature bending properties.

According to one aspect of the invention,
a conductor having a cross-sectional area of 225 mm ² or more and 275 mm ² or less;
an insulator provided to cover the outer periphery of the conductor;
a wire sheath provided to cover the outer periphery of the insulator;
An electric wire having
The conductor is
A child stranded wire obtained by twisting 42 or more strands with a diameter of 0.46 mm or less,
a parent stranded wire obtained by twisting 37 or more of the child stranded wires;
has
The outer diameter of the conductor is 21.2 mm or more and 26.0 mm or less,
The insulator and the wire sheath are
Contains a total of 100 parts by weight of 20 to 40 parts by weight of chlorinated polyethylene with a chlorine content of 30 to 45% and an ethylene-vinyl acetate copolymer of 60 to 80 parts by weight. Consisting of a resin composition containing a base resin and a flame retardant,
An electric wire is provided in which the flame retardant includes antimony trioxide and is contained in an amount of 1 part by weight or more and 5 parts by weight or less based on 100 parts by weight of the base resin.

According to another aspect of the invention,
A cable is provided in which a plurality of wires according to the above aspect are twisted together.

ADVANTAGE OF THE INVENTION According to this invention, the electric wire and cable which improved flexibility and a low-temperature bending property can be provided.

It is a sectional view perpendicular to the axial direction of the electric wire concerning a 1st embodiment of the present invention. (a) and (b) are schematic side views showing a deflection test. It is sectional drawing orthogonal to the axial direction of the cable which concerns on 2nd Embodiment of this invention. It is sectional drawing orthogonal to the axial direction of the electric wire which concerns on 3rd Embodiment of this invention.

<First embodiment of the present invention>
(1) Electric Wire An electric wire according to a first embodiment of the present invention will be described with reference to FIG. FIG. 1 is a cross-sectional view perpendicular to the axial direction of the electric wire according to this embodiment.

As shown in FIG. 1, the electric wire 10 according to the present embodiment includes a conductor 110, an insulator 120 provided to cover the outer circumference of the conductor 110, and an insulator 120 provided to cover the outer circumference of the insulator 120. and a wire sheath 130 . The cross-sectional area of the conductor 110 is, for example, within ±10% of 250 mm ² , that is, 225 mm ² or more and 275 mm ² or less.

Here, as a result of diligent studies by the present inventors, when the cross-sectional area of the conductor 110 is 225 mm ² or more and 275 mm ² or less, the electric wire 10 having the predetermined characteristics in the bending test and the low-temperature bending test as described below is realized for the first time. was done.

A deflection test according to this embodiment will be described with reference to FIG. Figures 2(a) and (b) are schematic side views showing the bending test. As shown in FIG. 2( a ), in the bending test, first, one end of the electric wire 10 is fixed to the fixing table 520 and the other end of the electric wire 10 is fixed to the fixing table 520 under room temperature (23° C.) conditions. Protrude 400mm horizontally from (the fulcrum of). Next, as shown in FIG. 2(b), a weight 540 of 2 kg is attached to the other end of the electric wire 10, and the deflection amount (d) is measured after 30 seconds. The deflection amount (d) is obtained as the vertical distance from the position of the central axis of the wire 10 on the fixing table 520 to the position of the central axis of the other end of the bent wire 10 .

In the electric wire 10 of this embodiment, the deflection amount in the deflection test is, for example, 130 mm or more.

Next, the low-temperature bending test according to this embodiment will be described. In the low-temperature bending test, the electric wire 10 is wound with a bending diameter three times the diameter of the electric wire 10 under the condition of -40°C. For example, one turn of the wire 10 is wound around a cylinder having a diameter three times the diameter of the wire 10 . Next, the electric wire 10 is visually observed for cracks and splits. At this time, if cracks or cracks were visually observed in the bent portion, it was judged as unacceptable, and if the bent portion and the normal portion could not be visually distinguished, it was judged as acceptable. If the low-temperature bending test fails, there is a possibility that cracks or splits of 5 mm or more will occur in the bent portion.

In the electric wire 10 of this embodiment, no cracks or splits occur in the low-temperature bending test.

(Configuration of electric wire)
The electric wire 10 having predetermined characteristics in the above bending test and low-temperature bending test is configured, for example, as follows.

(conductor)
Conductor 110 has a plurality of strands. The wire is made of oxygen-free copper, copper alloy, copper-coated wire, or the like, preferably oxygen-free copper. The surface of the wire may be plated with tin, silver, nickel, or the like. In this embodiment, the wire is, for example, a tin-plated annealed copper wire.

The wire diameter is 0.46 mm or less. If the diameter of the wire exceeds 0.46 mm, the amount of deflection of the wire may be insufficient and the allowable bending radius of the wire may become large. On the other hand, since the wire diameter is 0.46 mm or less, the flexibility of the electric wire 10 can be improved, and the allowable bending radius of the electric wire 10 can be reduced. In this embodiment, the wire diameter is, for example, 0.45 mm. In addition, when the diameter of the wire is 0.45 mm, the tolerance of the diameter of the wire is, for example, 0.45±0.01 mm according to the JIS standard.

The conductor 110 has a child stranded wire (primary stranded wire) in which 42 or more strands are twisted, and a parent stranded wire (secondary stranded wire) in which 37 or more child stranded wires are twisted. This parent strand is the conductor 110 . In this embodiment, for example, it is preferable that the number of strands in the child stranded wire is 42, and the number of child stranded wires in the parent stranded wire is 37.

Further, in the present embodiment, for example, the child strands are bunch twists, and the parent strands are concentric strands. The collective twist here is a method of twisting a plurality of strands (or twisted wires) together in the same direction. A twisting method in which a plurality of strands (or stranded wires) are twisted concentrically around a center wire. Twisted wires obtained by collectively twisting are excellent in flexibility, but the wires (or stranded wires) may come loose, etc., which may affect the electrical properties of the electric wire. Therefore, in the present embodiment, the child strands are bunch-twisted and the parent strands are concentrically twisted, so that the loose strands in the child strands can be suppressed by concentrically twisting the parent strands. Therefore, both the flexibility of the conductor 110 and the electrical properties of the wire 10 can be achieved.

The cross-sectional area of the conductor 110 configured in this way is 225 mm ² or more and 275 mm ^{2 or} less as described above. At this time, the outer diameter (conductor finished outer diameter) of the conductor 110 is, for example, within ±10% of 23.6 mm, that is, 21.2 mm or more and 26.0 mm or less. In this embodiment, the conductor 110 has an outer diameter of, for example, 23.6 mm.

(insulator and wire sheath)
The insulator 120 and the wire sheath 130 of this embodiment are configured to have a predetermined hardness. Specifically, the Shore A hardness of the insulator 120 and the wire sheath 130 is, for example, 88 or less. The conductor 110 having the above structure and the insulator 120 and the wire sheath 130 having the above hardness can realize the wire 10 having predetermined characteristics in the bending test and the low-temperature bending test.

The insulator 120 having a Shore A hardness of 88 or less and the wire sheath 130 are configured, for example, as follows. In addition, since the insulator 120 and the wire sheath 130 have the following configurations, the wire 10 of the present embodiment not only has predetermined characteristics in the above-described bending test and low-temperature bending test, but also has excellent flame retardancy, It is possible to have both heat resistance and elongation properties.

(base resin)
Insulator 120 and wire sheath 130 are made of a resin composition containing a base resin containing chlorinated polyethylene (CPE) and ethylene-vinyl acetate copolymer (EVA).

The chlorine content in the CPE contained in the base resin is 30% or more and 45% or less, preferably 35% or more and 40% or less. If the amount of chlorine in the CPE is less than 30%, the insulator and wire sheath may become harder than the predetermined hardness, and the flame retardancy of the wire may decrease. On the other hand, in the present embodiment, the amount of chlorine in the CPE is 30% or more, so that the insulator 120 and the wire sheath 130 can be softened to a predetermined hardness or less, and the wire 10 can improve the flame retardancy of Furthermore, by setting the chlorine content in the CPE to 35% or more, the flexibility and flame retardancy of the electric wire 10 can be further improved. On the other hand, if the amount of chlorine in the CPE exceeds 45%, the heat resistance of the wire may become insufficient. In contrast, in the present embodiment, the heat resistance of the wire 10 can be improved by setting the chlorine content in the CPE to 45% or less. Furthermore, the heat resistance of the wire 10 can be further improved by setting the chlorine content in the CPE to 40% or less.

The content of CPE in the base resin is 20 parts by weight or more and 60 parts by weight or less when the entire base resin is 100 parts by weight. If the CPE content is less than 20 parts by weight, the elongation property (flexibility) of the electric wire tends to decrease, and the flame retardancy of the electric wire may become insufficient. On the other hand, in the present embodiment, since the content of CPE is 20 parts by weight or more, the elongation property of the electric wire 10 can be improved, and the flame retardancy of the electric wire 10 can be improved. Furthermore, the content of CPE is preferably 30 parts by weight or more. Thereby, the elongation property and flame retardancy of the electric wire 10 can be further improved. On the other hand, if the CPE content exceeds 60 parts by weight, the heat resistance of the wire may be insufficient. In contrast, in the present embodiment, the CPE content is 60 parts by weight or less, so that the heat resistance of the electric wire 10 can be improved. Furthermore, the content of CPE is preferably 40 parts by weight or less. Thereby, the heat resistance of the electric wire 10 can be further improved.

As the CPE of the base resin, a single CPE or a mixture of two or more CPEs can be used. In addition, as the CPE of the base resin, any of amorphous, anticrystalline, or crystalline CPE may be used.

The base resin contains 100 parts by weight in total of the CPE of 20 parts by weight or more and 60 parts by weight or less and the ethylene-vinyl acetate copolymer. That is, the content of the ethylene-vinyl copolymer (EVA) is 40 parts by weight or more and 80 parts by weight or less.

Since EVA is a polymer with low crystallinity, the wire 10 can be made soft. More preferably, the polyolefin resin is EVA having a VA content of 25% or more and 35% or less. When the amount of VA in EVA is less than 25%, EVA approaches crystalline polyethylene, and the insulator and wire sheath may become harder than the predetermined hardness. On the other hand, in the present embodiment, since the VA content in EVA is 25% or more, the crystallinity of EVA is lowered, and the insulator 120 and the wire sheath 130 are softened so as to have a predetermined hardness or less. can do. On the other hand, if the amount of VA in EVA exceeds 35%, the strength and heat resistance of the electric wire may deteriorate. On the other hand, in the present embodiment, the decrease in the strength and heat resistance of the electric wire 10 can be suppressed by setting the amount of VA in EVA to 35% or less.

(stabilizer)
The resin composition forming insulator 120 and wire sheath 130 contains, for example, a stabilizer made of hydrotalcite. The stabilizer hydrotalcite functions as an acid acceptor. The hydrotalcite of the present embodiment is, for example, _Mg6Al2 ( _CO3 )(OH) _16.4 ( _H2O ) _. The average particle size of hydrotalcite is, for example, 1 μm or more and 5 μm or less for a synthetic product. The average particle size in this embodiment means the particle size at 50% of the integrated value in the particle size distribution obtained by the laser diffraction/scattering method.

The content of hydrotalcite as a stabilizer is, for example, 3 parts by weight or more and 30 parts by weight or less when the base resin is 100 parts by weight. If the content of hydrotalcite is less than 3 parts by weight, the heat resistance of the electric wire may deteriorate. In contrast, in the present embodiment, the content of hydrotalcite is 3 parts by weight or more, so that the heat resistance of the electric wire 10 can be improved. On the other hand, if the content of hydrotalcite exceeds 30 parts by weight, the elongation property of the electric wire may deteriorate. On the other hand, when the content of hydrotalcite is 30 parts by weight or less, the elongation property of the electric wire 10 can be improved.

(Flame retardants)
In addition, the resin composition forming insulator 120 and wire sheath 130 contains, for example, a flame retardant. Flame retardants include, for example, antimony trioxide. The average particle size of antimony trioxide is, for example, 1 μm or more and 5 μm or less.

When the resin composition contains antimony trioxide as a flame retardant, the content of antimony trioxide is, for example, 1 part by weight or more and 5 parts by weight or less per 100 parts by weight of the base resin. If the content of antimony trioxide is less than 1 part by weight, it may not be possible to obtain the effect of improving flame retardancy as a flame retardant. On the other hand, in the present embodiment, the content of antimony trioxide is 1 part by weight or more, so that the effect of improving the flame retardancy can be exhibited. On the other hand, if the content of antimony trioxide exceeds 5 parts by weight, the insulator and wire sheath may become harder than the predetermined hardness. In contrast, when the content of antimony trioxide is 5 parts by weight or less, the insulator 120 and the wire sheath 130 can be softened to a predetermined hardness or less.

Other flame retardants include magnesium hydroxide, aluminum hydroxide, calcium hydroxide, amorphous silica, zinc compounds such as zinc hydroxystannate, zinc borate and zinc oxide, calcium borate, boron A boric acid compound such as barium oxide and barium metaborate, a phosphorus-based flame retardant, an intumescent flame retardant consisting of a mixture of a component that foams and a component that solidifies when burned, a brominated flame retardant, and a chlorine-based flame retardant. and a fuel. As a flame retardant, these flame retardants can be used singly or in combination of two or more.

(Other additives)
In addition to the above materials, the resin composition that constitutes the insulator 120 and the wire sheath 130 may optionally contain an antioxidant, a metal deactivator, a cross-linking agent, a cross-linking aid, a lubricant, an inorganic filler, Additives such as compatibilizers and colorants can be added. Furthermore, the resin composition may be crosslinked by radiation such as electron beams.

Examples of antioxidants include phenol antioxidants, sulfur antioxidants, amine antioxidants, phosphorus antioxidants, and the like.

Phenolic antioxidants include, for example, dibutylhydroxytoluene (BHT), pentaerythritol tetrakis [3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate], 1,3,5-tris ( 3,5-di-t-butyl-4-hydroxy-benzyl)-S-triazine-2,4,6-(1H,3H,5H)trione, thiodiethylenebis[3-(3,5-di-tert -Butyl-4-hydroxyphenyl)propionate] and the like. Preferably, the phenolic oxide star material is pentaerythritol tetrakis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate].

Examples of sulfur-based antioxidants include didodecyl 3,3'-thiodipropionate, ditridecyl 3,3'-thiodipropionate, dioctadecyl 3,3'-thiodipropionate, tetrakis[methylene-3- (dodecylthio)propionate]methane and the like. Preferably, the sulfur-based antioxidant is tetrakis[methylene-3-(dodecylthio)propionate]methane.

Examples of amine antioxidants include 6-ethoxy-1,2-dihydro-2,2,4-trimethylquinoline, phenyl-1-naphthylene, alkylated diphenylamine, octylated diphenylamine, 4,4′-bis( α,α-dimethylbenzyl)diphenylamine, 2,2,4-trimethyl-1,2-dihydroquinoline polymer, p-(p-toluenesulfonylamido)diphenylamine, N,N′-di-2-naphthyl-p- phenyldiamine, N,N'-diphenyl-p-phenylenediamine, N-phenyl-N'-isopropyl-p-phenylenediamine, N-phenyl-N'-(1,3-dimethylbutyl)-p-phenylenediamine, N-phenyl-N'-(3-methacryloyloxy-2-hydroxypropyl)-p-phenylenediamine, 1,3-benzenedicarboxylic acid bis[2-(1-oxo-2-phenoxypropyl)hydrazide], 2' ,3-bis[[3-[3,5-di-tert-butyl-4-hydroxyphenyl]propionyl]]propionohydrazide, 3-(N-salicyloylamino)-1H-1,2,4- triazole, dodecanedioic acid bis[N2-(2-hydroxybenzoyl)hydrado] and the like.

The metal deactivator has the effect of stabilizing metal ions through chelate formation and suppressing oxidative deterioration. Examples of metal deactivators include N-(2H-1,2,4-triazol-5-yl) salicylamide, dodecanedioate bis[N2-(2-hydroxybenzoyl)hydrazide], 2',3- bis[[3-[3,5-di-tert-butyl-4-hydroxyphenyl]propionyl]]propionohydrazide and the like. Preferably, the metal deactivator is 2',3-bis[[3-[3,5-di-tert-butyl-4-hydroxyphenyl]propionyl]]propionohydrazide.

Examples of cross-linking agents include organic peroxides, and specific examples include peroxyketals, dialkyl peroxides, diacyl peroxides, peroxyesters, and the like. Preferably, the cross-linking agent is a dialkyl peroxide. The content of the cross-linking agent is, for example, 0.1 to 3 parts by weight, preferably 0.5 to 1 part by weight, per 100 parts by weight of the base resin.

Examples of cross-linking aids include trimethylolpropane trimethacrylate (TMPT) and triallyl isocyanurate (TAIC).

Lubricants include fatty acids, fatty acid metal salts, fatty acid amides, and the like. Specifically, the lubricant includes, for example, zinc stearate. These lubricants can be used singly or in combination of two or more.

Examples of inorganic fillers include clay, talc, silica, calcium carbonate and the like. These inorganic fillers may be surface-treated with a surface-treating agent such as fatty acid or silane. Moreover, these inorganic fillers can be used individually by 1 type or in mixture of 2 or more types.

Colorants include, for example, carbon black. Examples of carbon black include carbon black for rubber (N900-N100: ASTM D1765-01).

Other coloring agents include, for example, a color masterbatch and the like.

The insulator 120 and the wire sheath 130 are configured by the resin composition as described above. For example, the resin composition forming the insulator 120 does not contain a coloring agent such as carbon black, and the resin composition forming the wire sheath 130 contains a coloring agent such as carbon black. In this embodiment, for example, the composition of the resin composition forming the wire sheath 130 is the same as that of the resin composition forming the insulator 120, except for a coloring agent such as carbon black.

The thickness of the insulator 120 configured as described above is, for example, 1.5 mm or more and 3.5 mm or less. In this embodiment, the insulator 120 has a thickness of, for example, 2.5 mm. Moreover, the thickness of the electric wire sheath 130 configured as described above is, for example, 1 mm or more and 3 mm or less. In this embodiment, the thickness of the wire sheath 130 is, for example, 2.0 mm.

The allowable bending radius of the electric wire 10 of this embodiment configured as described above is, for example, 90 mm or more and 160 mm or less. On the other hand, when compared with conventional CVs having an insulator made of crosslinked polyethylene and a wire sheath made of polyvinyl chloride, it can be seen that the conventional CV differs in the configuration of the conductor and the materials of the insulator and the wire sheath. In the case of having the same shape as the electric wire 10 of the present embodiment except for the above, the allowable bending radius of the CV is 224 mm or more. Therefore, in the electric wire 10 of this embodiment, the allowable bending radius can be made smaller than that of the conventional CV.

(2) Electric Wire Manufacturing Method Next, an electric wire manufacturing method according to the present embodiment will be described.

(Conductor formation process)
First, a predetermined number of strands having a diameter of 0.46 mm or less are prepared. Next, 42 or more strands are twisted together by bunch twisting to form child strands. Thirty-seven or more child strands are then twisted together in a concentric lay to form a parent strand. This parent strand becomes the conductor 110 .

(Kneading process)
A base resin containing predetermined amounts of chlorinated polyethylene and an ethylene-vinyl acetate copolymer, a stabilizer made of hydrotalcite, a flame retardant such as antimony trioxide, and other additives excluding a cross-linking agent. and are mixed and kneaded at a predetermined temperature by a pressure kneader. Next, a cross-linking agent is added and kneaded at a predetermined temperature for a predetermined time. Next, the kneaded product is formed into a pellet shape or a belt shape. As described above, the kneaded material for the insulator 120 is formed. Further, a colorant such as carbon black is added in the same manner as the kneaded material for the insulator 120 to form the kneaded material for the electric wire sheath 130 .

(Extrusion process)
For example, using a 115 mm extruder, the kneaded material for the insulator 120 and the kneaded material for the wire sheath 130 are extruded and coated on the conductor 110 . An insulator 120 and a wire sheath 130 having a predetermined thickness are formed so as to cover the outer circumference of the conductor 110 . Thereby, the intermediate body of the electric wire 10 is formed.

(Crosslinking step)
Next, the wire 10 intermediate is placed in a steam pipe having a predetermined steam pressure for a predetermined time. Thereby, the insulator 120 and the wire sheath 130 are crosslinked. The electric wire 10 is formed by the above.

(3) Effect of this embodiment According to this embodiment, one or more of the following effects can be obtained.

(a) According to the present embodiment, when the cross-sectional area of the conductor is 225 mm ² or more and 275 mm ² or less, the amount of deflection in a predetermined deflection test is 130 mm or more, and the predetermined For the first time, an electric wire 10 that does not crack or split in a low-temperature bending test has been realized. Since the bending amount of the electric wire 10 is 130 mm or more, the allowable bending radius of the electric wire 10 can be reduced, and the electric wire 10 can be bent and laid even in a narrow place. In addition, since no cracks or fissures occur in the low-temperature bending test, it is possible to suppress the occurrence of local defects that degrade the performance of the electric wire 10 even when the electric wire 10 is used in a low-temperature environment. Thus, according to this embodiment, it is possible to provide the electric wire 10 with improved flexibility and low-temperature bending properties.

(b) According to the present embodiment, the conductor 110 includes a child stranded wire in which 42 or more strands having a diameter of 0.46 mm or less are twisted together, a parent stranded wire in which 37 or more child stranded wires are twisted, , and the outer diameter of the conductor 110 is 21.2 mm or more and 26.0 mm or less. The Shore A hardness of insulator 120 and wire sheath 130 is 88 or less. By having the conductor 110 having the above configuration and the insulator 120 and the wire sheath 130 having the above hardness, it is possible to satisfy the predetermined characteristics in the bending test and the low-temperature bending test.

(c) According to the present embodiment, the insulator 120 and the wire sheath 130 are composed of chlorinated polyethylene (CPE) having a chlorine content of 30% or more and 45% or less and containing 20 parts by weight or more and 60 parts by weight or less of ethylene acetic acid. and a base resin containing 100 parts by weight in total of a vinyl copolymer.

Here, when compared with conventional CVs having an insulator made of crosslinked polyethylene and a sheath made of polyvinyl chloride, it is difficult for conventional CVs to satisfy the predetermined characteristics in the above-described bending test and low-temperature bending test. At the same time, it has become more difficult to meet the desired flame retardancy, heat resistance, and elongation properties. Even if the composition of the insulator and wire sheath in the CV were changed to soften the CV, it was difficult to simultaneously improve the flame retardancy, heat resistance and elongation properties.

In contrast, according to the present embodiment, the insulator 120 and the wire sheath 130 are made of the resin composition containing the base resin described above, so that the Shore A hardness of the insulator 120 and the wire sheath 130 is 88 or less. becomes possible. Accordingly, in combination with the configuration of the conductor 110 described above, it is possible to satisfy predetermined characteristics in the bending test and the low-temperature bending test. In addition, since the insulator 120 and the wire sheath 130 are made of the resin composition containing the base resin described above, flexibility and low-temperature bending characteristics are improved, and flame retardancy, heat resistance, and elongation characteristics are improved in a well-balanced manner. be able to.

(d) According to the present embodiment, the ethylene-vinyl acetate copolymer (EVA) contained in the base resin is a polymer with low crystallinity, so the electric wire 10 can be made soft.

(e) According to the present embodiment, the content of hydrotalcite as a stabilizer is, for example, 3 parts by weight or more and 30 parts by weight or less when the base resin is 100 parts by weight. When the content of hydrotalcite is 3 parts by weight or more, the heat resistance of the electric wire 10 can be improved. When the content of hydrotalcite is 30 parts by weight or less, the elongation property of the electric wire 10 can be improved.

(f) According to the present embodiment, the child strands of conductor 110 are cluster strands and the parent strands of conductor 110 are concentric strands. As a result, the looseness of the strands in the child stranded wire can be suppressed by concentrically twisting the parent stranded wire. Therefore, both the flexibility of the conductor 110 and the electrical properties of the wire 10 can be achieved.

<Second embodiment of the present invention>
A second embodiment of the present invention will be described with reference to FIG. FIG. 3 is a cross-sectional view orthogonal to the axial direction of the cable according to this embodiment.

This embodiment differs from the first embodiment in that a cable is configured by a plurality of electric wires. Hereinafter, only elements different from the first embodiment will be described, and elements that are substantially the same as those described in the first embodiment will be given the same reference numerals, and description thereof will be omitted.

As shown in FIG. 3, the cable 20 has multiple electric wires 12 having the same configuration as in the first embodiment. The conductor 110 of this embodiment has the same configuration as in the first embodiment, and the insulator 120 and wire sheath 130 of this embodiment are made of the same resin composition as in the first embodiment. Therefore, each electric wire 12 used in the cable 20 has a bending amount of 130 mm or more in the bending test, and no cracks or splits occur in the low-temperature bending test.

In this embodiment, the cable 20 has three wires 12, for example. The three wires 12 are twisted together.

Interpositions 240 are provided so as to cover the outer circumferences of the plurality of electric wires 12 . Interposer 240 is, for example, paper or the like that is twisted together with wire 12 .

A press winding tape 250 is wound so as to cover the outer circumference of the intervention 240 . The presser winding tape 250 is made of, for example, PET, polyethylene, cloth, or the like. Note that the interposition 240 and the pressing tape 250 may not be used.

Moreover, a cable sheath 260 is provided so as to cover the outer periphery of the pressing winding tape 250 . The cable sheath 260 of this embodiment is made of the same resin composition as the wire sheath 130, for example.

According to this embodiment, since the cable 20 has a plurality of electric wires 12 having the same configuration as in the first embodiment, it is possible to provide the cable 20 with improved flexibility and low-temperature bending characteristics.

<Third embodiment of the present invention>
A third embodiment of the present invention will be described with reference to FIG. FIG. 4 is a cross-sectional view orthogonal to the axial direction of the electric wire according to this embodiment.

This embodiment differs from the first embodiment in that a separator is provided. Hereinafter, only elements different from the first embodiment will be described, and elements that are substantially the same as those described in the first embodiment will be given the same reference numerals, and description thereof will be omitted.

As shown in FIG. 4, the electric wire 14 includes a conductor 110 having a cross-sectional area of 225 mm ² or more and 275 mm ^{2 or} less, a separator 160 provided so as to cover the outer circumference of the conductor 110, and the separator 160 covering the outer circumference. and a wire sheath 130 provided so as to cover the outer periphery of the insulator 120 . The conductor 110 of this embodiment has the same configuration as in the first embodiment, and the insulator 120 and wire sheath 130 of this embodiment are made of the same resin composition as in the first embodiment.

The separator 160 is made of polyester tape or nylon tape, for example. By interposing the separator 160 between the conductor 110 and the insulator 120 , the insulator 120 and the wire sheath 130 can be easily peeled off at the end of the wire 14 .

Similarly to the first embodiment, the electric wire 14 of the present embodiment also has a deflection amount of 130 mm or more in the deflection test, and no cracks or splits occur in the low-temperature bending test.

According to this embodiment, even if the wire 14 has the separator 160, it is possible to achieve the same flexibility and low-temperature bending characteristics as the wire 10 of the first embodiment.

(Another embodiment of the present invention)
Although one embodiment of the present invention has been specifically described above, the present invention is not limited to the above-described embodiment, and can be appropriately modified without departing from the scope of the invention.

In the above-described third embodiment, the case where the electric wire 14 has the separator 160 has been described, but in a cable similar to that of the second embodiment, a separator may be interposed between the conductor and the insulator.

Next, examples according to the present invention will be described.

Samples 1 to 14 (sample 5 is a reference example) were produced as follows, and predetermined evaluations were performed on each sample.

<Preparation of sample>
(Samples 1-5)
For Sample 1, wire and sheet samples were formed as shown in Tables 1 and 2 below. First, 42 strands of tin-plated annealed copper wire having a diameter of 0.45 mm were prepared. The 42 strands were then twisted together by bunch twisting to form child strands. The 37 child strands were then plied together with a concentric twist to form the parent strand. This formed a conductor with a cross-sectional area of 250 mm ² and an outer diameter of 23.6 mm. In Tables 1 to 3 below, the "number of child stranded wires" means the number of strands in the child stranded wire, and the "number of parent stranded wires" means the number of child stranded wires in the parent stranded wire. It is about the number of books.

Next, as shown in Tables 1 and 2 below, each material except for the cross-linking agent was blended and kneaded with a pressure kneader at a starting temperature of 40°C and an ending temperature of 120°C. Next, a cross-linking agent was added and kneaded at 100° C. for 5 minutes. Next, the kneaded product was molded into a pellet shape or a belt shape. As described above, a kneaded material for an insulator was formed. Further, a predetermined amount of carbon black was added as a coloring agent in the same manner as the kneaded material for the insulator to form a kneaded material for the electric wire sheath.

In the preparation of the electric wire sample of Sample 1, a 115 mm extruder was used to extrude and coat the kneaded material for the insulator and the kneaded material for the electric wire sheath on the outer periphery of the conductor. An insulator having a thickness of 2.5 mm and a wire sheath having a thickness of 2.0 mm were formed so as to cover the outer periphery of the conductor. This formed an intermediate wire sample. Next, the wire sample intermediate was put into a steam pipe with a steam pressure of 15 kg/cm ² to crosslink the insulator and the wire sheath. As described above, an electric wire sample of Sample 1 was produced.

Further, in the production of the sheet sample of Sample 1, each of the kneaded material for the insulator and the kneaded material for the electric wire sheath was formed into a sheet using a 6-inch open roll. Next, the sheet-shaped kneaded material was press-molded at 180° C. for 1 minute using a press molding machine so as to have a predetermined thickness. Sheet samples of the insulator and wire sheath of Sample 1 were thus produced.

In the electric wire samples of Samples 2 to 5, as shown in Tables 1 and 2 below, the composition of the conductor and the composition of the resin composition constituting the insulator and the electric wire sheath were compared with those of Sample 1. It was changed within a predetermined range from the wire sample. In the sheet samples of Samples 2 to 5, the composition of the resin composition constituting the insulator and the wire sheath was changed from that of the sheet sample of Sample 1 within a predetermined range in the same manner as the wire samples.

(Samples 6-9)
In the electric wire samples of Samples 6 to 9, as shown in Tables 1 and 2 below, the resin composition constituting the insulator and the electric wire sheath was changed while the structure of the conductor was the same as that of the electric wire sample of Sample 1. The composition was varied from the Sample 1 wire sample outside of the specified range. In the sheet samples of Samples 6 to 9, the composition of the resin composition constituting the insulator and the wire sheath was changed from the sheet sample of Sample 1 outside the predetermined range in the same manner as the wire samples.

(Samples 10-14)
In the electric wire samples of Samples 10 and 11, as shown in Table 3 below, the composition of the resin composition constituting the insulator and the electric wire sheath was the same as that of the electric wire sample of Sample 1, while the structure of the conductor was the same as that of the electric wire sample of Sample 1. 1 was changed outside the predetermined range. In the sheet samples of Samples 10 and 11, the composition of the resin composition constituting the insulator and the wire sheath was the same as that of the sheet sample of Sample 1.

In the electric wire samples of Samples 12 to 14, as shown in Table 3 below, the composition of the resin composition constituting the insulator and the electric wire sheath was different from that of the electric wire sample of Sample 1 while the composition of the conductor was the same as that of the electric wire sample of Sample 1. It was changed from the wire sample of No. 1. Specifically, the EVA in the resin composition was changed to a material different from the EVA in the electric wire sample of Sample 1. In the sheet samples of Samples 12 to 14, the composition of the resin composition constituting the insulator and the wire sheath was changed from that of the sheet sample of Sample 1 in the same manner as in the wire samples.

<Evaluation>
Samples 1 to 14 were evaluated as follows.

(Bending test)
The wire samples of Samples 1-14 were subjected to deflection testing as described above. In the deflection test, the case where the amount of deflection was less than 130 mm was rated as x (failed), and the case where the amount of deflection was 130 mm or more was rated as ◯ (passed).

(Low temperature bending test)
The wire samples of Samples 1-14 were subjected to cold bend testing as described above. In the low-temperature bending test, the case where cracks or cracks were visually confirmed in the bent portion was evaluated as × (failed), and the case where the bent portion and the normal portion could not be visually distinguished was evaluated as ◯ (passed).

(Hardness test)
For Samples 1 to 14, the Shore A hardness was obtained by conducting a hardness test in accordance with JIS K6253 with the insulator sheet sample and the wire sheath sheet sample stacked.

(Tensile test)
A test piece obtained by extracting a conductor from each of the electric wire samples of Samples 1 to 14 was used, and a tensile test was performed on the test piece according to JIS C3005. If the tensile strength is less than 10 MPa, it is x (failed); , passed with a margin). In addition, when the elongation in the tensile test is less than 350%, x (failed), when the elongation is 350% or more and less than 400%, ◯ (pass), and when the elongation is 400% or more ◎ (double circle, passed with margin).

(Flame retardant test)
Oxygen index (OI) measurements were performed in accordance with JIS K6269 for both the insulator and wire sheath sheet samples of Samples 1-14. A case where the OI was less than 26 was rated as x (failed), and a case where the OI was 26 or more was rated as ◯ (passed).

(Heat resistance test)
A heat resistance test was performed on the electric wire samples of Samples 1 to 14 as follows. Specifically, using a gear-type aging tester conforming to JIS K6257, it is aged at 160 ° C. for 30 days, and then a tensile test is performed on a test piece obtained by pulling out the conductor from the aged wire sample. The elongation of the test piece of the sample was measured. The case where the absolute value of the elongation of the test piece of the wire sample at this time is less than 50% is x (failed), and the case where the absolute value of the elongation of the test piece of the wire sample is 50% or more is ◯ (passed). and

<Evaluation results>
First, Tables 1 and 3 describe the results of flexibility and low-temperature bending properties as basic properties.

As shown in Table 1, in samples 1 to 9, the diameter of the conductor wire is 0.46 mm or less, 42 or more strands are twisted to form a twisted wire, and 37 or more strands are twisted. The wires were twisted together to form a parent strand. Moreover, the Shore A hardness of the insulator and the wire sheath was 88 or less due to the predetermined composition of the resin composition forming the insulator and the wire sheath. As a result, in the electric wire samples of Samples 1 to 9, the deflection amount was 130 mm or more in the deflection test, and no cracks or splits occurred in the low-temperature bending test. Therefore, it was confirmed that samples 1 to 9 had improved flexibility and low-temperature bending properties.

Here, in Tables 1 and 3, Samples 1 to 9 and Samples 10 and 11 are compared with respect to the conductor configuration. Samples 10 and 11, in which the wire strand diameter of the conductor was greater than 0.46 mm and the twist configuration of the conductor was changed, had a deflection amount of less than 130 mm in the deflection test. It is thought that the wire sample became difficult to bend (hardened) because the wire of the conductor was thick. Therefore, it is preferable that the diameter of the strands of the conductor is set to 0.46 mm or less, 42 or more strands are twisted together to form a child stranded wire, and 37 or more strand strands are twisted together to form a main stranded wire. was confirmed.

Tables 1 and 3 compare Samples 1-9 and Samples 12-14 with respect to the hardness of the insulator and wire sheath. Samples 12 to 14, in which the Shore A hardness of the insulator and wire sheath exceeded 88, had a deflection amount of less than 130 mm in the deflection test. Since the amount of VA in EVA in the resin composition constituting the insulator and the wire sheath was less than 25%, the Shore A hardness of the insulator and the wire sheath exceeded 88, and the wire sample became difficult to bend (hardened )it is conceivable that. Therefore, it was confirmed that the Shore A hardness of the insulator and wire sheath is preferably 88 or less.

Next, Table 2 describes the results of flame retardancy, heat resistance and elongation properties.

As shown in Table 2, in samples 1 to 5, chlorinated polyethylene having a chlorine content of 30% or more and 45% or less and 20 parts by weight or more and 60 parts by weight or less, an ethylene/vinyl acetate copolymer, a total of 100 parts by weight of a base resin, a stabilizer containing 3 parts by weight or more and 30 parts by weight or less of hydrotalcite, and a flame retardant containing 1 part by weight or more and 5 parts by weight or less of antimony trioxide. composition was used. As a result, the wire samples of Samples 1 to 5 passed the results of the flame retardancy test, heat resistance test, and tensile test. Therefore, it was confirmed that samples 1 to 5 had improved flame retardancy, heat resistance, and elongation properties.

Table 2 compares Samples 1 to 5 and Samples 6 and 7 in terms of CPE content. Sample 6, in which the content of CPE exceeded 60 parts by weight, failed in heat resistance. On the other hand, Sample 7, in which the content of CPE was less than 20 parts by weight, showed a tendency of deterioration in elongation properties and failed in flame retardancy. Therefore, it was confirmed that the content of CPE is preferably 20 parts by weight or more and 60 parts by weight or less.

In Table 2, Samples 1 to 5 and Samples 8 and 9 are compared with respect to the content of hydrotalcite as a stabilizer. Sample 8 containing less than 3 parts by weight of hydrotalcite failed in heat resistance. On the other hand, Sample 9, in which the content of hydrotalcite exceeded 30 parts by weight, failed in elongation properties. Therefore, it was confirmed that the content of hydrotalcite is preferably 3 parts by weight or more and 30 parts by weight or less.

From the above results, it was confirmed that according to this example, it is possible to provide an electric wire and a cable with improved flexibility and low-temperature bending properties, as well as improved flame retardancy, heat resistance, and elongation properties. .

<Preferred embodiment of the present invention>
Preferred embodiments of the present invention are additionally described below.

[Appendix 1]
According to one aspect of the invention,
a conductor having a cross-sectional area of 225 mm ² or more and 275 mm ² or less;
an insulator provided to cover the outer periphery of the conductor;
a wire sheath provided to cover the outer periphery of the insulator;
An electric wire having
The conductor is
A child stranded wire obtained by twisting 42 or more strands with a diameter of 0.46 mm or less,
a parent stranded wire obtained by twisting 37 or more of the child stranded wires;
has
The outer diameter of the conductor is 21.2 mm or more and 26.0 mm or less,
The insulator and the wire sheath are
Contains a total of 100 parts by weight of 20 to 40 parts by weight of chlorinated polyethylene with a chlorine content of 30 to 45% and an ethylene-vinyl acetate copolymer of 60 to 80 parts by weight. Consisting of a resin composition containing a base resin and a flame retardant,
An electric wire is provided in which the flame retardant includes antimony trioxide and is contained in an amount of 1 part by weight or more and 5 parts by weight or less based on 100 parts by weight of the base resin.

[Appendix 2]
The electric wire according to Supplementary Note 1, preferably
Shore A hardness of the insulator and the wire sheath is 88 or less.

[Appendix 3]
The electric wire according to Supplementary Note 1, preferably
The resin composition contains a stabilizer containing hydrotalcite.

[Appendix 4]
The electric wire according to Appendix 3, preferably
The resin composition contains 3 parts by weight or more and 30 parts by weight or less of the hydrotalcite stabilizer with respect to 100 parts by weight of the base resin.

[Appendix 5]
The electric wire according to appendices 1 to 4, preferably
The oxygen index in the flame retardancy test according to JIS K6269 is 26 or more,
The elongation in the tensile test after aging at 160 ° C. for 30 days using a gear aging tester conforming to JIS K6257 is 50% or more,
The elongation in a tensile test according to JIS C3005 is 350% or more.

[Appendix 6]
The electric wire according to Supplementary Note 1, preferably
the child strands are set strands,
The parent strands are concentrically laid.

[Appendix 7]
According to one aspect of the invention,
A cable is provided by twisting a plurality of electric wires according to Appendices 1 to 6 and providing a cable sheath around the outer circumference of the wire.

10, 12, 14 Electric wire 20 Cable 110 Conductor 120 Insulator 130 Electric wire sheath 160 Separator 240 Interposition 250 Press winding tape 260 Cable sheath 520 Fixed base 540 Weight

Claims (5)

a conductor having a cross-sectional area of 225 mm ² or more and 275 mm ² or less;
an insulator provided to cover the outer periphery of the conductor;
a wire sheath provided to cover the outer periphery of the insulator;
An electric wire having
The conductor is
A child stranded wire obtained by twisting 42 or more strands with a diameter of 0.46 mm or less,
a parent stranded wire obtained by twisting 37 or more of the child stranded wires;
has
The outer diameter of the conductor is 21.2 mm or more and 26.0 mm or less,
the child strands are set strands,
the parent strand is concentrically laid,
The insulator and the wire sheath are
20 to 40 parts by weight of chlorinated polyethylene having a chlorine content of 30% to 40% and 60 to 80 parts by weight of ethylene-vinyl acetate having a VA content of 28% to 35%. Consists of a resin composition containing a base resin and a flame retardant containing a total of 100 parts by weight of a polymer,
The flame retardant contains antimony trioxide and contains 1 part by weight or more and 5 parts by weight or less with respect to 100 parts by weight of the base resin,
The electric wire, wherein the Shore A hardness of the insulator and the electric wire sheath is 88 or less. The electric wire according to claim 1, wherein the resin composition contains a stabilizer containing hydrotalcite. 3. The electric wire according to claim 2, wherein the resin composition contains 3 parts by weight or more and 30 parts by weight or less of the stabilizer comprising the hydrotalcite with respect to 100 parts by weight of the base resin. The oxygen index in the flame retardancy test according to JIS K6269 is 26 or more,
The elongation in the tensile test after aging at 160 ° C. for 30 days using a gear aging tester conforming to JIS K6257 is 50% or more,
The electric wire according to any one of claims 1 to 3, which has an elongation of 350% or more in a tensile test according to JIS C3005. A cable obtained by twisting a plurality of the electric wires according to any one of claims 1 to 4 and providing a cable sheath on the outer periphery thereof.

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