Electric wiring track

Abstract

To provide an electric wiring track having an excellent heat dissipation, achieving a compact wire layout.SOLUTION: An electric wiring track includes a plurality of electric wires layed out. Each of the plurality of electric wires is arranged neighboring to each other. Each of the plurality of electric wires includes: a conductor composed of a single line or a conductor with a plurality of strands twisted together; and an insulation layer coating an outer periphery of the conductor. At least one of the plurality of electric wires is a heat dissipating wire. A thermal conductivity is 0.40 W / m.K or more in an insulation layer of the heat dissipating wire at 25°C.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to electrical wires and lines.

[0002] In recent years, there has been a demand for ever-increasing transmission capacity and speed for electric wires and cables. In general, a cable is constructed by, for example, covering an insulated electric wire, which is made up of multiple conductors covered with an insulating layer, with an outer sheath layer placed around it. A line in which multiple electric wires are laid is called an electric wire line, and a line in which multiple cables are laid is called a cable line.

[0003] In cable lines, when multiple cables are laid in close contact with each other, heat tends to build up, which impairs the heat dissipation of the entire cable line. For this reason, multiple cables are arranged with a gap between them in order to reduce the allowable current or to make it easier to dissipate heat by utilizing air convection. In response to this, a conventional technique has been proposed that proposes a large-capacity cable line in which a two-piece metal case made of a nonmagnetic metal material is attached to a cable assembly formed by closely assembling single-core cables adjacent to each other so as to surround the entire length of the cable assembly, and heat dissipation fins are provided along the entire length of the metal case. This allows the cable line to have a compact configuration that is economical, and reduces the magnetic field that causes communication problems (see Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Utility Model Publication No. 61-022441 Summary of the Invention

[0005] The electric wire line of the present disclosure is an electric wire line in which a plurality of electric wires are laid, the plurality of electric wires being arranged adjacent to one another, the plurality of electric wires having a conductor made of a solid wire or a conductor made of a plurality of strands twisted together, and an insulating layer covering the outer periphery of the conductor, at least one of the plurality of electric wires being a heat dissipative electric wire, and the insulating layer of the heat dissipative electric wire having a thermal conductivity of 0.40 W / m·K or more at 25°C. [Brief description of the drawings]

[0006] [Figure 1] FIG. 1 is a schematic configuration diagram showing an electric wire and line according to a first embodiment. [Diagram 2] FIG. 2 is a schematic cross-sectional view showing the heat dissipative electric wire according to the first embodiment. [Diagram 3] FIG. 3 is a schematic configuration diagram showing an electric wire and line according to another embodiment. [Figure 4] FIG. 4 is a schematic configuration diagram showing an electric wire and line according to another embodiment. [Diagram 5] FIG. 5 is a schematic configuration diagram showing an electric wire and line according to another embodiment. [Figure 6] FIG. 6 is a schematic configuration diagram showing an electric wire and line according to another embodiment. [Figure 7] FIG. 7 is a schematic configuration diagram showing an electric wire and line according to another embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0007] [Problem that this disclosure aims to solve] Unlike cables with a jacket layer, when laying electric wires, they basically need to be laid in a pipe from the viewpoint of protection. For this reason, multiple electric wires are drawn into the pipe and laid, but in electric wire lines using electric wires, if multiple electric wires are laid in close contact with each other, heat tends to build up, so the heat dissipation performance of the entire electric wire line is impaired and the allowable current must be reduced. In the above-mentioned conventional technology, the cables are arranged in close proximity to each other, while the surface area is expanded by providing heat dissipation fins along the entire length of the metal case, making it easy to disperse the trapped heat. However, a metal case with heat dissipation fins along the entire length cannot be bent, making it difficult to draw it into a pipe and lay it. In addition, there is a risk that the demand for compact electric wire installation cannot be fully met.

[0008] The present disclosure aims to provide an electric wire line that has excellent heat dissipation properties and allows for compact electric wire installation.

[0009] [Effects of this disclosure] According to the present disclosure, it is possible to provide an electric wire line that has excellent heat dissipation properties and enables compact electric wire installation.

[0010] [Description of the embodiments of the present disclosure] First, the embodiments of the present disclosure will be listed and described.

[0011] The electric wire and line of the present disclosure includes: (1) An electric wire line in which a plurality of electric wires are laid, the plurality of electric wires being arranged adjacent to one another, the plurality of electric wires having a conductor made of a single wire or a conductor made of a plurality of strands twisted together, and an insulating layer covering the outer periphery of the conductor, at least one of the plurality of electric wires being a heat dissipating electric wire, and the thermal conductivity of the insulating layer of the heat dissipating electric wire at 25°C being 0.40 W / m K or more.

[0012] The electric wire line has excellent heat dissipation properties and allows for compact electric wire installation. The inventors have found that by arranging at least one heat-dissipating electric wire in the electric wire line and placing the electric wires adjacent to each other in a state where the electric wires are in close contact with each other, heat that tends to build up inside is released while being conducted through the heat-dissipating electric wire. The electric wire line has the above configuration, which suppresses a decrease in allowable current caused by placing the electric wires in close contact, and by placing the electric wires adjacent to each other, a compact arrangement can be achieved. Therefore, the electric wire line has excellent heat dissipation properties, can suppress a temperature rise of the conductor, can reduce power loss, and allows for compact electric wire installation. Here, "arranged adjacent to each other" means that in the configuration of the electric wire line, each electric wire is in contact with at least one other electric wire.

[0013] (2) In the above (1), all of the electric wires may be the heat dissipating electric wires. When all of the electric wires in the electric wire / line are the heat dissipating electric wires, heat dissipation can be further improved.

[0014] (3) In the above (1), the heat dissipative electric wire may be arranged in a central portion. By arranging the heat dissipative electric wire in a central portion of the electric wire / line, heat dissipation can be further improved. The "central portion" refers to a region excluding a range of 30% of the entire length in the row direction from both ends in the row direction in a cross-sectional view of the electric wire / line.

[0015] (4) In the above (1), the plurality of electric wires may be arranged in multiple stages, with the heat dissipative electric wire being arranged in the top stage. In the electric wire line, the heat dissipative electric wire is arranged in the top stage, thereby further improving heat dissipation. The above "multiple stages" means that the electric wires are arranged in two or more stages in the stage direction, which is the vertical direction.

[0016] (5) In any one of (1) to (4) above, the insulating layer in the heat dissipating electric wire contains a resin component, a first filler, and a second filler, the resin component contains an olefin resin and a resin incompatible with the olefin resin, the olefin resin and the resin incompatible with the olefin resin form a sea-island structure, the first filler is made of graphite, the second filler is made of a metal oxide, a metal hydroxide, or a combination thereof, a mass ratio of the first filler to the resin component is 10 / 100 or more and 80 / 100 or less, and the volume resistivity of the insulating layer in the heat dissipating electric wire is 1×10 13 The electrical resistance may be Ω·cm or more. In the electric wire / line, the insulating layer of the heat dissipating electric wire contains an olefin resin with a large crystal content as the resin component, thereby improving the tensile strength and oil resistance. In addition, the insulating layer of the heat dissipating electric wire contains the first filler made of graphite and the second filler made of a metal oxide, a metal hydroxide or a combination thereof, and the mass ratio of the first filler to the resin component is 10 / 100 or more and 80 / 100 or less, thereby improving thermal conductivity. Therefore, heat of the conductor is easily released to the outside, and the effect of suppressing the temperature rise of the conductor is high. In addition, the volume resistivity of the insulating layer of the heat dissipating electric wire is 1×10 13 By having a resistivity of Ω·cm or more, the insulation and voltage resistance of the electric wire included in the electric wire / line can be improved. Furthermore, by the resin component including an olefin resin and a resin incompatible with the olefin resin forming a sea-island structure, the first filler, which is difficult to disperse in the olefin resin, can be unevenly distributed in the incompatible resin, thereby further improving the heat dissipation of the insulating layer in the heat dissipating electric wire. Therefore, in the electric wire / line, the temperature rise of the conductor can be further suppressed to reduce power loss, and the insulation, mechanical strength, and oil resistance of the insulating layer in the heat dissipating electric wire can be improved.

[0017] The "volume resistivity" refers to an electrical resistance value measured by a double ring electrode method based on JIS-K6271:2008. The "resin incompatible with olefin resin" refers to a resin incompatible with olefin resin, and can be confirmed, for example, by observing a cross section of the insulating layer perpendicular to the longitudinal direction of the electric wire using a transmission electron microscope (TEM). The olefin resin and the incompatible resin have a sea-island structure when the cross section is observed with an electron microscope. By adopting such a dispersed state of the sea-island structure, the physical property behaviors originating from both the olefin resin and the resin incompatible with this olefin resin appear independently, and the mutual incompatibility allows the properties of both resins to be fully exhibited.

[0018] [Details of the embodiment of the present disclosure] Hereinafter, an electric wire and line according to an embodiment of the present disclosure will be described in detail with reference to the drawings as appropriate.

[0019] <Electric wires and tracks> The electric wire line includes a plurality of electric wires, and is mainly installed in indoor wiring or a conduit. A switchboard, a conduit, a metal duct, or other piping may be used as a support for the electric wire line. The electric wire includes a conductor and an insulating layer that covers the outer periphery of the conductor. In the electric wire line, at least one of the plurality of electric wires is a heat dissipating electric wire.

[0020] [First embodiment] FIG. 1 is a schematic diagram showing an electric wire and line according to the first embodiment, showing a cross section of a plurality of electric wires laid in two rows and three rows. An electric wire and line 10 according to the first embodiment may include a general-purpose electric wire 8 other than the heat-dissipating electric wire 1. In the electric wire and line 10, one heat-dissipating electric wire 1 and five general-purpose electric wires 8 are arranged adjacent to each other. The heat-dissipating electric wire 1 includes a conductor 2 and an insulating layer 3 that covers the outer periphery of the conductor 2. The insulating layer of the electric wire included in the general-purpose electric wire 8 is not particularly limited and may be made of a known synthetic resin for insulating layers.

[0021] [Heat dissipating wire] In the heat dissipative electric wire 1 laid in the electric wire / line 10 according to the first embodiment, the thermal conductivity of the insulating layer 3 at 25° C. is 0.40 W / m·K or more.

[0022] 2 is a schematic cross-sectional view showing an example of a heat dissipating electric wire. The heat dissipating electric wire 1 includes a conductor 2 and an insulating layer 3 that covers the outer periphery of the conductor 2. The conductor 2 may be a conductor made of a single wire or a conductor made by twisting a plurality of wires together. In the heat dissipating electric wire 1, an additional layer such as a primer treatment layer may be provided between the conductor 2 and the insulating layer 3.

[0023] <conductor> The conductor 2 is a metal linear body that is responsible for electrical conduction of the heat dissipating electric wire 1. Examples of the conductor 2 include a round wire having a circular cross-sectional shape, a rectangular wire having a rounded square cross-sectional shape, and a rectangular wire having a rounded rectangular cross-sectional shape. The conductor 2 may be a single linear body as shown in FIG. 2, or a twisted wire body in which multiple thin wires are twisted together.

[0024] The material for the conductor 2 may be, for example, a metal such as copper, aluminum, nickel, silver, or iron, or an alloy thereof, but from the viewpoints of electrical conductivity and workability, copper or aluminum may be used. The conductor 2 may also have a multi-layer structure in which a coating made of another metal is laminated on the outer peripheral surface of a metal linear body.

[0025] The lower limit of the average cross-sectional area (including the gaps between the wires) of the conductor 2 is 2 mm 2 may be 8mm 2 It may be 14mm 2 On the other hand, the upper limit of the average cross-sectional area of ​​the conductor 2 is 600 mm 2 may be 500 mm 2 may be 400 mm 2 When the average cross-sectional area of ​​the conductor 2 is equal to or greater than the above lower limit, a sufficient current can flow. When the average cross-sectional area of ​​the conductor 2 is equal to or less than the above upper limit, sufficient bending resistance can be obtained. Here, the "average cross-sectional area" refers to the average value of values ​​measured at any ten points on the cross section.

[0026] Insulating layer The insulating layer 3 may contain a resin component, a first filler and a second filler.

[0027] The average thickness of the insulating layer 3 is not particularly limited, but the lower limit of the average thickness may be, for example, 0.8 mm or 1.0 mm. On the other hand, the upper limit of the average thickness of the insulating layer 3 may be 10 mm or 7 mm. When the average thickness of the insulating layer 3 is equal to or greater than the lower limit, the insulating properties of the insulating layer 3 can be improved. When the average thickness of the insulating layer 3 is equal to or less than the upper limit, the flexibility can be improved. Here, the "average thickness" refers to the average value of thicknesses measured at any ten points. Note that the same definition is used hereinafter when referring to "average thickness" for other members, etc.

[0028] In the electric wire / line 10, the lower limit of the thermal conductivity of the insulating layer 3 in the heat dissipative electric wire 1 at 25° C. is 0.40 W / m·K, and may be 0.50 W / m·K or 0.60 W / m·K. By setting the lower limit of the thermal conductivity of the insulating layer 3 in the heat dissipative electric wire 1 at 25° C. to 0.40 W / m·K, the heat dissipation of the electric wire / line 10 can be improved.

[0029] In the electric wire / line 10, the lower limit of the volume resistivity of the insulating layer 3 in the heat dissipating electric wire 1 is 1×10 13 Ω cm may be 1×10 15 Ω cm may be 2×10 15 The volume resistivity of the insulating layer 3 may be 1×10 13 By setting the electrical resistance to Ω·cm or more, the heat dissipative electric wire 1 included in the electric wire / line 10 can have good insulation properties and voltage resistance.

[0030] The insulating layer 3 may contain an olefin-based resin as a resin component. When the insulating layer 3 contains an olefin-based resin as a resin component, the tensile strength and oil resistance can be improved. Examples of the olefin-based resin include polypropylene (PP) and polyethylene (PE).

[0031] Examples of polypropylene include homopolypropylene, random polypropylene, and block polypropylene. Examples of random polypropylene include propylene-α-olefin copolymers, which are copolymers of propylene and ethylene or α-olefins having 4 to 20 carbon atoms. Block polypropylene is a resin composed of homopolypropylene as a main component, random copolymer elastomer as a copolymer component, and an ethylene polymer as an optional component.

[0032] Examples of polyethylene include high density polyethylene (PE), very low density polyethylene (VLDPE), low density polyethylene (LDPE), linear low density polyethylene (LLDPE), and cross-linked polyethylene.

[0033] The olefin resin may be polypropylene, or may be random polypropylene or block polypropylene. When the olefin resin is random polypropylene or block polypropylene, it is possible to improve the tensile strength and oil resistance while suppressing a significant decrease in tensile elongation.

[0034] The resin component may contain, in addition to the olefin resin, a resin incompatible with the olefin resin. By containing the resin incompatible with the olefin resin, the first filler, which is difficult to disperse in the olefin resin, can be unevenly distributed in the resin incompatible with the olefin resin, thereby further improving the heat dissipation property.

[0035] The olefin resin and the resin incompatible with the olefin resin may form a sea-island structure. The resin component includes an olefin resin and a resin incompatible with the olefin resin, and these resins form a sea-island structure, whereby the first filler unevenly distributed in the incompatible resin can be dispersed, thereby further improving heat dissipation.

[0036] Examples of resins that are incompatible with olefin resins include styrene copolymers, polyvinyl chloride, polyurethane, fluororesins, fluororubbers, and silicones. Among these, styrene copolymers that have good dispersibility of the first filler and can improve tensile elongation may be used. The incompatible resins may include one or more types.

[0037] Examples of styrene-based copolymers include styrene-ethylene block copolymers (SE), styrene / ethylene-butylene / ethylene block copolymers (SEBC) or their hydrogenated products, styrene / ethylene-butylene / styrene block copolymers (SEBS) or their hydrogenated products, styrene / ethylene-propylene / styrene block copolymers (SEPS), styrene / ethylene-ethylene-propylene-styrene block copolymers (SEEPS), and hydrogenated styrene butadiene rubber (HSBR).

[0038] The lower limit of the content of the structural unit derived from styrene in the styrene-based copolymer may be 5% by mass or 8% by mass. The upper limit of the content of the structural unit derived from styrene may be 40% by mass or 38% by mass. By setting the content of the structural unit derived from styrene in the above range, the tensile elongation and oil resistance can be further improved.

[0039] When the resin component contains a styrene copolymer as a resin incompatible with the olefin resin, the lower limit of the mass ratio of the styrene copolymer to the olefin resin may be 20 / 80 or 30 / 70. The upper limit of the mass ratio of the styrene copolymer to the olefin resin may be 80 / 20 or less or 70 / 30. By setting the mass ratio of the styrene copolymer to the olefin resin within the above range, the tensile properties, heat dissipation properties and oil resistance can be further improved.

[0040] The insulating layer 3 may contain a resin other than the olefin resin and the resin used as the incompatible resin, such as polyvinyl chloride, polyurethane, fluororesin, fluororubber, silicone, or polyester resin.

[0041] <First filler> The first filler is made of graphite. When the insulating layer 3 contains the first filler made of graphite, electrical conductivity can be increased and heat dissipation can be improved.

[0042] The lower limit of the mass ratio of the first filler to the resin component may be 10 / 100, 20 / 100, or 25 / 100. The upper limit of the mass ratio of the first filler to the resin component may be 80 / 100, 75 / 100, or 70 / 100. By setting the mass ratio of the first filler to the resin component within the above range, it is possible to achieve both heat dissipation and insulation properties and to achieve good compatibility.

[0043] The lower limit of the average particle size of the graphite may be 0.5 μm, 1 μm, or 5 μm. Meanwhile, the upper limit of the average particle size may be 100 μm, 50 μm, or 30 μm. When the average particle size of the graphite is 0.5 μm or more, the thermal conductivity at 25° C. can be improved. Meanwhile, when the average particle size of the graphite is 100 μm or less, the tensile elongation can be improved. When the average particle size of the graphite is within the above range, the heat dissipation can be further improved. The above-mentioned "average particle size" means the median diameter (D50) which is the value at which the volume-based cumulative distribution calculated in accordance with JIS-Z-8819-2:2001 is 50%. Specifically, the median diameter (D50) can be a value measured by the following method. Measurement is performed using a laser diffraction type particle size distribution measuring device as a measuring device. A scattering measurement mode is adopted, and a laser beam is irradiated onto a wet cell in which the dispersion liquid in which the particles of the sample to be measured are dispersed in a dispersion solvent is circulated, and the scattered light distribution is obtained from the measurement sample.Then, the scattered light distribution is approximated by a log-normal distribution, and the particle diameter at the cumulative degree of 50% (D50) is taken as the median diameter.

[0044] The insulating layer 3 contains a second filler made of a metal oxide, a metal hydroxide, or a combination thereof. When the insulating layer 3 contains a second filler made of a metal oxide, a metal hydroxide, or a combination thereof, the heat dissipation property and the insulating property can be improved.

[0045] Examples of the metal oxide include magnesium oxide, zinc oxide, aluminum oxide, titanium oxide, and calcium oxide.

[0046] Examples of the metal hydroxide include magnesium hydroxide, aluminum hydroxide, and calcium hydroxide.

[0047] The lower limit of the mass ratio of the second filler to the resin component may be 30 / 100 or 50 / 100. The upper limit of the mass ratio of the second filler to the resin component may be 200 / 100 or 180 / 100. In the electric wire, when the mass ratio of the second filler to the resin component is within the above range, both the insulation property and the tensile elongation can be well achieved.

[0048] The lower limit of the average particle size ratio of the first filler to the second filler may be 1.1 or 5.0. When the average particle size ratio of the first filler to the second filler is 1.1 or more, the heat dissipation property can be further improved. The upper limit of the average particle size ratio of the first filler to the second filler is not particularly limited, but may be, for example, 100 times or less from the viewpoint that the tensile elongation decreases when the particle size of graphite is too large.

[0049] The insulating layer 3 may contain other additives as necessary. Examples of such additives include a flame retardant, a flame retardant assistant, an antioxidant, a lubricant, a colorant, a reflectivity imparting agent, an opacifying agent, a processing stabilizer, and a plasticizer.

[0050] [Manufacturing method of heat dissipating electric wire] The method for producing the heat dissipating electric wire is not particularly limited, but may include, for example, the following steps. (1) A step of preparing an insulating layer-forming composition for forming an insulating layer (an insulating layer-forming composition preparation step) (2) A step of coating a conductor with a composition for forming an insulating layer (a step of coating a composition for forming an insulating layer)

[0051] (1) Preparation of composition for forming insulating layer In the insulating layer forming composition preparation step, an insulating layer forming composition for forming an insulating layer is prepared. The insulating layer forming composition is prepared by mixing a resin component, a filler, and other additives as necessary, for example, with a melt mixer. As the melt mixer, a known one, for example, an open roll, a Banbury mixer, a pressure kneader, a single-shaft mixer, or a multi-shaft mixer can be used. The insulating layer-forming composition of the present disclosure may be crosslinked by any of chemical crosslinking, silane crosslinking, and radiation crosslinking.

[0052] (2) Insulation layer forming composition coating process The insulating layer-forming composition coating step can be performed, for example, by a method of extruding the insulating layer-forming composition onto the conductor using a melt extruder. This results in an insulating layer being an extrusion molded body coating the conductor. In the heat dissipating electric wire of the electric wire / line in the first embodiment, the thermal conductivity of the insulating layer at 25°C is 0.40 W / m·K or more.

[0053] [How to make electric wires and tracks] A method for producing the electric wire line includes, for example, a step of preparing a plurality of electric wires including at least one heat dissipating electric wire, and a step of laying the plurality of electric wires in multiple rows and columns so that the plurality of electric wires are arranged adjacent to each other as shown in Fig. 1. In the electric wire line, a general-purpose electric wire can also be laid.

[0054] The electric wire line has excellent heat dissipation properties and allows for compact electric wire installation.

[0055] [Second embodiment] 3 is a schematic diagram showing an electric wire and line according to a second embodiment. In the electric wire and line 20, a plurality of electric wires are arranged adjacent to each other in multiple stages, and the heat dissipative electric wire 1 is arranged in the center. In the electric wire and line 20, the heat dissipative electric wire 1 is arranged in the center, thereby further improving heat dissipation. When a plurality of electric wires are arranged adjacent to each other in multiple stages, the heat dissipative electric wire 1 may be arranged in all the centers of each stage, or the heat dissipative electric wire 1 may be arranged only in the centers of some stages.

[0056] [Third embodiment] 4 is a schematic diagram showing an electric wire and line according to a third embodiment. In the electric wire and line 30, a plurality of electric wires are arranged adjacent to each other in multiple stages, and the heat dissipative electric wire 1 is arranged in the entire uppermost stage. In the electric wire and line 30, the heat dissipative electric wire 1 is arranged in the entire uppermost stage, so that the heat dissipation performance can be further improved.

[0057] [Fourth embodiment] 5 is a schematic diagram showing an electric wire / line according to a fourth embodiment. In the electric wire / line 40, a plurality of electric wires are arranged in multiple stages, and the heat dissipative electric wire 1 is arranged in the entire lowest stage. In the electric wire / line 40, by arranging the heat dissipative electric wire 1 in the entire lowest stage, it is possible to further improve heat dissipation.

[0058] [Fifth embodiment] 6 is a schematic diagram showing an electric wire / line according to a fifth embodiment. In the electric wire / line 50, a plurality of electric wires are arranged adjacent to each other in multiple stages, and all of the electric wires are made of heat-dissipating electric wires 1. In the electric wire / line 50, all of the electric wires are made of heat-dissipating electric wires 1 and arranged adjacent to each other, thereby further improving heat dissipation.

[0059] [Sixth embodiment] 7 is a schematic diagram showing an electric wire line according to a sixth embodiment. In the electric wire line 60, a plurality of electric wires are laid in parallel. In the electric wire line 60, a plurality of electric wires are arranged adjacent to each other in one row, and all of the electric wires are composed of heat dissipative electric wires 1. In this way, even when a plurality of electric wires are laid in parallel in one row, by arranging the heat dissipative electric wires 1 adjacent to each other, it is possible to have excellent heat dissipation properties, suppress the temperature rise of the conductor, reduce power loss, and enable compact electric wire laying.

[0060] [Other embodiments] The embodiments disclosed herein should be considered to be illustrative and not restrictive in all respects. The scope of the present invention is not limited to the configurations of the above-described embodiments, but is indicated by the claims, and is intended to include all modifications within the meaning and scope of the claims. EXAMPLES

[0061] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to the following examples.

[0062] <Wire No.K1~No.K9> Single-layer insulating layers No. K1 to No. K9 were produced by the following procedure.

[0063] [Resin component] 1. Olefin resin The following components were used as the olefin-based resin in the resin component. (1) Random polypropylene (random PP) MFR 1.3 (g / 10 min), flexural modulus 950MPa (2) Very low density polyethylene (VLDPE) (3) Cross-linked polyethylene (cross-linked PE) The melt flow rate (MFR) is a value measured using a melt indexer at a measurement temperature of 230° C. and a load of 2.16 kg according to a method in accordance with JIS-K7210-1:2014 (Method A: Mass Measurement Method). The flexural modulus is a value measured according to a method in accordance with JIS-K7171:2016. 2. Styrene copolymer The following styrene-based copolymer was used as a resin incompatible with the olefin-based resin in the resin component. (1) Styrene / ethylene-butylene / styrene block copolymer (SEBS) (styrene structural unit content: 12% by mass) Shore A hardness 42 (2) SEBS (styrene structural unit content: 18% by mass) Shore A hardness 67 The term "Shore A hardness" refers to the hardness measured by a type A durometer based on JIS-K6253: 2012. The term "content of styrene structural units" refers to the content of structural units derived from styrene in the styrene-based copolymer.

[0064] [First filler] As the first filler, the following two types of graphite were used. (1) Thin graphite (average particle size 22 μm) (2) Spherical graphite (average particle size 20 μm)

[0065] [Second filler] As the second filler, the following two types of filler were used. (1) Magnesium hydroxide (average particle size 0.8 μm) (2) Zinc oxide type 1 (average particle size 0.75 μm)

[0066] Using the above resin component, first filler and second filler, compositions for forming insulating layers No. K1 to No. K9 were prepared. The composition and content of the insulating layer are shown in Table 1. "-" indicates that the corresponding component was not used.

[0067] [Creating the insulating layer] The insulating layers No. K1 to No. K9 were produced by extrusion molding using the insulating layer-forming composition. An extrusion die was used for the extrusion molding. The extrusion molding was performed at a die temperature of 180° C. and a linear speed of 5 m / min, and insulating layers No. K1 to No. K9 with an average thickness of 2.7 mm were obtained.

[0068] <Wire No.K1~No.K9> Electric wires No. K1 to No. K9 were produced according to the following procedure. Conductor cross-sectional area is 38 mm 2 The electric wires No.K1 to No.K9 were made with an outer diameter of 9.4 mm and a length of 3 m, in which the outer circumference of the conductor was covered with an insulating layer No.K1 to No.K9 with an average thickness of 2.7 mm. Of the electric wires No.K1 to No.K9, No.K1 to No.K7 are heat dissipating electric wires, and No.K8 and No.K9 are general-purpose electric wires.

[0069] [Insulation layer and wire evaluation] The insulation layers and electric wires of No. K1 to No. K9 were evaluated for thermal conductivity, volume resistivity, tensile strength, tensile elongation, tensile strength and tensile elongation after oil resistance tests, conductor temperature when current is applied, withstand voltage, and the presence or absence of a sea-island structure in the cross section of the insulation layer.

[0070] (Thermal Conductivity) A press sheet measuring φ150 mm x thickness 0.5 mm was prepared as a test sample from the composition for forming an insulating layer using a heat press machine, and the thermal conductivity at 25°C was measured in accordance with ISO-22007-3 (temperature wave method). A higher thermal conductivity [W / m K] indicates a higher heat dissipation property of the insulating layer. A thermal conductivity of 0.40 W / m K or higher at 25°C can be said to have excellent heat dissipation properties.

[0071] (Volume resistivity (insulation)) A press sheet measuring φ150 mm and thickness 1 mm was prepared as a test sample from the composition for forming an insulating layer using a heat press machine, and electrical resistance was measured using the double ring electrode method defined in JIS-K6271:2008. The volume resistivity was calculated from the measured value. A higher volume resistivity [Ω·cm] value indicates higher insulating properties of the insulating layer. The volume resistivity is expressed as a value of 1×10 13 When the resistance is Ω·cm or more, the insulating layer has excellent insulating properties.

[0072] (tensile strength and tensile elongation) The tensile strength [MPa] and tensile elongation [%] of each insulating layer were measured in accordance with JIS-K7162: 1994. When the tensile strength is 10 MPa or more and the tensile elongation is 200% or more, the mechanical strength of the insulating layer can be said to be excellent.

[0073] (Tensile strength and tensile elongation after oil resistance test) Based on JIS-C3005:2014, the specimens were immersed in JIS No. 2 test oil at 70℃ for 4 hours, after which the retention rate [%] of tensile strength [MPa] and tensile elongation [%] was measured to evaluate the oil resistance. The tensile strength [MPa] and tensile elongation [%] of the insulating layer were measured in accordance with JIS-K7162:1994. The retention rate Y of each of the tensile strength and tensile elongation was calculated by the following formula. Remaining rate Y[%]=C 3 / C 2 In the above formula, C 2 is the tensile strength or tensile elongation before immersion, and C 3 is the tensile strength or tensile elongation after immersion. The greater the tensile strength retention and tensile elongation retention after the oil resistance test, the better the oil resistance. When the tensile strength retention is 80% or more and the elongation retention is 60% or more, the oil resistance of the insulating layer can be said to be good.

[0074] (Whether or not the insulating layer has an island structure) The presence or absence of a sea-island structure in the cross section of the insulation layer was determined by preparing thin-film sections from the insulation layers taken from wires No. K1 to No. K9 using the freezing microtome method, staining the samples with ruthenium tetroxide, osmium tetroxide, tungsten phosphate, etc., and observing them under a transmission electron microscope and visually judging.

[0075] (Conductor temperature when current is applied) The conductor temperature during current flow was measured by passing a current of 230 A through the electric wires No. K1 to No. K9 and measuring the temperature of the conductor surface at the center of the electric wires.

[0076] (Voltage resistance) In accordance with JIS-C3605:2002, the electric wires No. K1 to No. K9 were charged with 2000V and evaluated for the presence or absence of dielectric breakdown. The evaluation was made according to the following two stages. When the evaluation was A, the effect was good. A: No insulation breakdown has occurred. B: Dielectric breakdown occurred.

[0077] The evaluation results of the insulating layers and electric wires of Nos. K1 to K9 are shown in Table 1.

[0078] [Table 1]

[0079] The results in Table 1 show that the insulation layers of Tests No. K1 to No. K7, in which the thermal conductivity of the insulation layer at 25°C was 0.40 W / m K or more, had a lower conductor temperature when current was applied, compared to the insulation layers of Tests No. K8 and K9, in which the thermal conductivity was less than 0.40 W / m K. Volume resistivity is 1×10 13 The insulating layers of Test No. K1 to Test No. K9, which had a resistance of Ω·cm or more, showed good results in the withstand voltage test. In addition, the insulating layers of Test Nos. K1 to K7, in which the insulating layers contain an olefin-based resin and a resin incompatible with the olefin-based resin as resin components, the olefin-based resin and the incompatible resin forming a sea-island structure, the first filler is graphite, and the second filler is a metal oxide or metal hydroxide, and the mass ratio of the first filler to the resin component is 10 / 100 or more and 80 / 100 or less, had excellent heat dissipation properties, oil resistance, and mechanical strength.

[0080] <Evaluation of electric wires and lines> (Conductor temperature when heat dissipating wire and general-purpose wire are combined) Using heat-dissipating electric wires and general-purpose electric wires, electric wire lines No. 1 to No. 6 were created, in which six electric wires were laid in two rows and three columns as shown in Table 2. The six electric wires were laid adjacent to each other using cable ties. The heat-dissipating electric wires used were electric wires with a heat-dissipating insulation layer No. K1 (thermal conductivity 0.65 W / m K), and the general-purpose electric wires used were electric wires with a general-purpose insulation layer No. K9 (thermal conductivity 0.28 W / m K).

[0081] The arrangement of the heat dissipating electric wires and general-purpose electric wires in No. 1 to No. 6 is as follows. No.1: All six wires are heat dissipating wires No.2: The two central wires in the upper and lower rows are heat dissipating wires. No.3: The one in the center of the top row is a heat dissipating wire. No.4: The top three are heat dissipating wires No.5: One of the wires at the top end is a heat dissipating wire No.6: All six are general-purpose wires

[0082] Next, a current of 140A was applied, which brings the conductor temperature to around 90°C, and the temperature of the conductor surface in the center of each wire was measured to evaluate the temperature rise when a current is applied when a heat-dissipating wire is combined with a general-purpose wire. The conductor temperatures [°C] of the wires at each installation position in the wire and cable routes No. 1 to No. 6 are shown in Table 2. In addition, in the wire and cable route arrangement format in Table 2, black circles indicate heat-dissipating wires and white circles indicate general-purpose wires.

[0083] [Table 2]

[0084] As shown in Table 2, in the electric wire line in which six electric wires are laid in two rows and three columns, the electric wire lines No. 1 to No. 5, which include heat-dissipating electric wires with an insulation layer with a thermal conductivity of 0.40 W / m·K or more at 25°C, had a lower maximum conductor temperature than the electric wire line No. 6, in which all six electric wires are general-purpose electric wires, even though the six electric wires were laid in close contact with each other. Among them, No. 1, in which all six electric wires are heat-dissipating electric wires, and No. 4, in which the three electric wires in the upper row are heat-dissipating electric wires, showed particularly good heat dissipation. In addition, a comparison between No. 3, in which one electric wire in the center of the upper row is a heat-dissipating electric wire, and No. 5, in which one electric wire at the end of the upper row is a heat-dissipating electric wire, shows that arranging the heat-dissipating electric wire in the center can reduce the maximum conductor temperature.

[0085] (Conductor temperature when electric wires with different thermal conductivities are installed for each electric wire line) Using heat-dissipating electric wires and general-purpose electric wires, electric wire lines No. 7 to No. 10 were created, in which six electric wires were laid in two rows and three columns as shown in Table 3. The six electric wires were laid adjacent to each other using cable ties. Two types of heat-dissipating electric wires were used: an electric wire with a heat-dissipating insulation layer No. K1 (thermal conductivity 0.65 W / m K) and an electric wire with a heat-dissipating insulation layer No. K7 (thermal conductivity 0.40 W / m K). Two types of general-purpose electric wires were used: an electric wire with a general-purpose insulation layer No. K8 (thermal conductivity 0.25 W / m K) and an electric wire with a general-purpose insulation layer No. K9 (thermal conductivity 0.28 W / m K).

[0086] The arrangement of the heat dissipating electric wires and general-purpose electric wires in Nos. 7 to 10 is as follows. No.7: All six wires are heat dissipating wires (wires with heat dissipating insulation layer No.K1) No.8: All six wires are heat dissipating wires (wires with heat dissipating insulation layer No.K7) No.9: All six are general-purpose wires (wires with general-purpose insulation layer No.K9) No.10: All six are general-purpose wires (wires with general-purpose insulation layer No. K8)

[0087] Next, a current of 140A was applied and the temperature of the conductor surface in the center of each wire was measured to evaluate the temperature rise when a current was applied when wires with different thermal conductivities were installed in each wire line. The conductor temperatures [°C] of the wires at each installation position in wire lines No. 7 to No. 10 are shown in Table 3. In addition, in the wire line layout format in Table 3, black circles indicate heat dissipating wires and white circles indicate general-purpose wires.

[0088] [Table 3]

[0089] As shown in Table 3, the No. 7 and No. 8 electric wire lines, which are composed of heat-dissipating electric wires with an insulation layer having a thermal conductivity of 0.40 W / m K or more at 25°C for all six electric wires, had better heat dissipation than the No. 9 and No. 10 electric wire lines, which are composed of all six general-purpose electric wires, even though the six electric wires were laid in close contact with each other. Among them, No. 7, whose heat-dissipating electric wire has a thermal conductivity of 0.65 W / m K, had particularly good heat dissipation.

[0090] The above results show that the electric wire and cable line has excellent heat dissipation properties and allows for compact electric wire installation. [Explanation of symbols]

[0091] 1 Heat dissipating wire 2 Conductors 3. Insulation layer 8 Other general-purpose electric wires 10, 20, 30, 40, 50, 60 Electric lines

Claims

1. An electric wire line in which a plurality of electric wires are laid, The plurality of electric wires are arranged adjacent to each other, The electric wire has a conductor made of a single wire or a conductor made of a plurality of stranded wires, and an insulating layer that covers the outer periphery of the conductor, At least one of the plurality of electric wires is a heat dissipating electric wire, The heat dissipating electric wire has an insulating layer having a thermal conductivity of 0.40 W / m·K or more at 25° C.

2. 2. The electric wire / line according to claim 1, wherein all of said electric wires are said heat dissipating electric wires.

3. The electric wire and line according to claim 1 , wherein the heat dissipating electric wire is disposed in a central portion.

4. The plurality of electric wires are arranged in multiple stages, The electric wire and line according to claim 1 , wherein the heat dissipating electric wire is arranged in the uppermost stage.

5. the insulating layer in the heat dissipating electric wire contains a resin component, a first filler and a second filler, the resin component includes an olefin-based resin and a resin incompatible with the olefin-based resin, the olefin-based resin and a resin incompatible with the olefin-based resin form a sea-island structure, The first filler is made of graphite, The second filler is made of a metal oxide, a metal hydroxide, or a combination thereof; a mass ratio of the first filler to the resin component is 10 / 100 or more and 80 / 100 or less; The volume resistivity of the insulating layer in the heat dissipating electric wire is 1×10 １３ The electric wire and line according to any one of claims 1 to 4, wherein the electric wire and line has a resistance of Ω·cm or more.

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