cable

Abstract

This cable comprises an electric wire and a metal layer covering the electric wire, wherein: the electric wire includes a conductor and an insulating material provided on an outer peripheral surface of the conductor; the insulating material contains a polyolefin-based resin, a phenolic antioxidant, and a copper damage inhibitor; the content of the polyolefin-based resin in the insulating material is at least 98 mass%; the insulating material contains 0.01-0.5 parts by mass of the phenolic antioxidant and 0.01-0.5 parts by mass of the copper damage inhibitor, with respect to 100 parts by mass of the polyolefin-based resin; the dielectric loss tangent at 10 GHz is at most 3.0×10-4; the metal layer includes a longitudinally attached metal layer configured by longitudinally attaching a metal tape; the metal tape partially overlaps in the width direction of the metal tape to form an overlapped part; and the width of the overlapped part is 1 / 20 to 1 / 3 of the width of the metal tape.

Description

cable

[0001] The present disclosure relates to a cable. This application claims priority to Japanese Patent Application No. 2023-106957, filed on June 29, 2023. The entire contents of the Japanese patent application are incorporated herein by reference.

[0002] With the need for autonomous driving technology and driver assistance functions in automobiles, there is a demand for ever greater capacity and speed in the transmission of information from in-vehicle information cables. In-vehicle information cables consist of conductors made of metals such as copper covered with an insulating material made of polyolefin resin. Since transmission loss is positively correlated with the signal frequency and the dielectric loss tangent of the insulating material, in order to increase the speed of signal transmission, it is necessary to reduce the dielectric loss tangent of the insulating material, further reducing transmission loss and ensuring stable signal transmission.

[0003] In-vehicle information electric wires are generally used as in-vehicle information transmission cables in which one or more in-vehicle information electric wires are covered with an outer sheath material for mechanical protection and to improve flame retardancy, oil resistance, etc. In-vehicle information transmission cables are sometimes used bundled with electric wires, cables, and wire harnesses that use polyvinyl chloride (hereinafter also referred to as "PVC (polyvinyl chloride)") as the outer sheath material. In this case, antioxidants contained in the insulation of the in-vehicle information transmission cable may migrate to the PVC of the surrounding electric wires, etc., causing oxidative degradation of the insulation of the in-vehicle information transmission cable, or hydrochloric acid gas generated from the PVC of the surrounding electric wires, etc. may cause degradation of the insulation of the in-vehicle information transmission cable.

[0004] Patent Document 1 discloses a technology for suppressing deterioration of the insulation of an in-vehicle information transmission cable when the in-vehicle information transmission cable is bundled with a wire harness having an insulation material made of PVC. Specifically, a large amount of antioxidant is added to the insulation material to suppress deterioration of the insulation material.

[0005] Japanese Patent Application Laid-Open No. 2022-60751

[0006] A cable according to the present disclosure is a cable comprising an electric wire and a metal layer covering the electric wire, wherein the electric wire includes a conductor and an insulating material provided on an outer peripheral surface of the conductor, the insulating material including a polyolefin resin, a phenolic antioxidant, and a copper inhibitor, the polyolefin resin content of the insulating material being 98% by mass or more, the insulating material including 0.01 parts by mass or more and 0.5 parts by mass or less of the phenolic antioxidant and 0.01 parts by mass or more and 0.5 parts by mass or less of the copper inhibitor relative to 100 parts by mass of the polyolefin resin, and a dielectric loss tangent at 10 GHz of 3.0×10 －４ The cable is as follows: the metal layer includes a longitudinally attached metal layer formed by longitudinally attaching metal tapes, the metal tapes partially overlap each other in the width direction of the metal tapes to form an overlapping portion, and the width of the overlapping portion is 1 / 20 to 1 / 3 of the width of the metal tapes.

[0007] FIG. 1 is a schematic cross-sectional view of cables according to Embodiments 1 and 2. FIG. 2 is a schematic cross-sectional view of a cable according to Embodiment 3. FIG. 3 is a diagram illustrating longitudinal attachment of a metal tape. FIG. 4 is a diagram illustrating horizontal winding of a metal tape. FIG. 5A is a schematic cross-sectional view of an example of a cable according to Embodiment 4. FIG. 5B is a schematic cross-sectional view of another example of a cable according to Embodiment 4. FIG. 6A is a schematic cross-sectional view of an example of a cable according to Embodiment 5. FIG. 6B is a schematic cross-sectional view of another example of a cable according to Embodiment 5. FIG. 7 is a schematic cross-sectional view of a cable according to Embodiment 6. FIG. 8 is a schematic cross-sectional view of another example of a cable according to Embodiment 6. FIG. 9 is a schematic cross-sectional view of a cable according to Embodiment 7. FIG. 10 is a schematic cross-sectional view of another example of a cable according to Embodiment 7. FIG. 11A is a cross-sectional view of an example of a test structure used in a test to evaluate degradation suppression of insulation properties. FIG. 11B is a cross-sectional view of another example of a test structure used in a test to evaluate degradation suppression of insulation properties.

[0008] [Problem to be Solved by the Present Disclosure] Adding a large amount of antioxidant is undesirable because it increases the dielectric loss tangent of the insulating material, which leads to impeding high-speed signal transmission.

[0009] Therefore, an object of the present disclosure is to provide a cable that does not increase the dielectric loss tangent of the cable insulation and that suppresses deterioration of the cable insulation, even when bundled with a wire harness having insulation made of PVC. Deterioration of the insulation here refers to both heat aging and deterioration caused by harmful gases generated from the PVC.

[0010] [Effects of the Present Disclosure] According to the present disclosure, it is possible to provide a cable in which the dielectric loss tangent of the cable insulation does not increase and deterioration of the cable insulation is suppressed, even when the cable is bundled with a wire harness having insulation made of PVC.

[0011] [Description of Embodiments of the Present Disclosure] First, embodiments of the present disclosure will be listed and described. (1) A cable of the present disclosure is a cable including an electric wire and a metal layer covering the electric wire, wherein the electric wire includes a conductor and an insulating material provided on an outer peripheral surface of the conductor, wherein the insulating material includes a polyolefin resin, a phenolic antioxidant, and a copper inhibitor, wherein the polyolefin resin content of the insulating material is 98% by mass or more, and the insulating material contains 0.01 to 0.5 parts by mass of the phenolic antioxidant and 0.01 to 0.5 parts by mass of the copper inhibitor relative to 100 parts by mass of the polyolefin resin, and wherein the dielectric loss tangent at 10 GHz is 3.0 × 10 －４ The cable is as follows: the metal layer includes a longitudinally attached metal layer formed by longitudinally attaching metal tapes, the metal tapes partially overlap each other in the width direction of the metal tapes to form an overlapping portion, and the width of the overlapping portion is 1 / 20 to 1 / 3 of the width of the metal tapes.

[0012] (2) A cable according to the present disclosure is a cable including an electric wire and a metal layer covering the electric wire, wherein the electric wire includes a conductor and an insulating material provided on an outer peripheral surface of the conductor, the insulating material including a polyolefin resin, a phenolic antioxidant, and a copper inhibitor, the polyolefin resin content of the insulating material is 98% by mass or more, the insulating material includes 0.01 parts by mass or more and 0.5 parts by mass or less of the phenolic antioxidant and 0.01 parts by mass or more and 0.5 parts by mass or less of the copper inhibitor relative to 100 parts by mass of the polyolefin resin, and the dielectric loss tangent at 10 GHz is 3.0 × 10 －４ the metal layer includes a horizontally wound metal layer formed by horizontally winding a metal tape, the metal tapes overlap each other in the width direction of the metal tape to form an overlapping portion, the width of the overlapping portion is 1 / 5 to 1 / 2 of the width of the metal tape, and the turning angle of the metal tape is greater than 0° and less than 80°.

[0013] According to the above (1) and (2), it is possible to provide a cable in which the dielectric loss tangent of the cable insulation does not increase and deterioration of the cable insulation is suppressed even when the cable is bundled with a wire harness having insulation made of PVC. The reasons for this are presumed to be as follows.

[0014] The insulating material of the cable of the present disclosure contains a polyolefin resin and a phenolic antioxidant. In the insulating material, the amount of the phenolic antioxidant is 0.01 parts by mass or more and 0.5 parts by mass or less per 100 parts by mass of the polyolefin resin, so that the amount of the phenolic antioxidant is small. Therefore, the dielectric loss tangent of the insulating material does not increase, and oxidative degradation of the insulating material is suppressed.

[0015] The metal layer of the cable of the present disclosure also has a shielding effect against the intrusion of hydrochloric acid gas generated from the PVC of the surrounding wire harness into the cable interior, thereby preventing the hydrochloric acid gas from reaching the cable insulation and suppressing deterioration of the insulation.

[0016] The metal layer of the cable of the present disclosure also has a noise blocking effect, allowing the cable of the present disclosure to transmit signals reliably.

[0017] The cable of the present disclosure has a small dielectric loss tangent and is particularly suitable for high-speed transmission.

[0018] (3) In the above (1) or (2), the cable may include a plurality of the electric wires, and the metal layer may cover each of the electric wires.

[0019] This allows for a higher noise shielding effect to be achieved.

[0020] (4) In the above (1) or (2), the cable may have a first group of electric wires consisting of two or more electric wires, and the metal layer may cover the first group of electric wires collectively.

[0021] This allows a high noise shielding effect to be obtained while keeping costs down.

[0022] (5) In any one of the above (1) to (4), the cable may further include a metal braid covering a surface of the metal layer opposite to the surface facing the electric wire.

[0023] This makes it possible to obtain a higher noise shielding effect, and the cable is easy to bend and wire.

[0024] (6) In any one of the above (1) to (5), the metal tape may include a thin metal layer, and the thickness of the thin metal layer may be 0.1 μm or more and 20 μm or less.

[0025] This prevents damage to the metal tape and also improves the flexibility of the metal tape.

[0026] (7) In any one of the above (1) to (6), the polyolefin resin may be a polypropylene resin.

[0027] This suppresses increases in the dielectric loss tangent and dielectric constant of the insulating material, allowing the cable to have excellent transmission characteristics.

[0028] (8) In any of (1) to (7) above, the cable further includes an outer covering material covering the metal layer, the outer covering material containing a polyolefin resin and a metal hydroxide, the metal hydroxide being at least one selected from the group consisting of magnesium hydroxide and aluminum hydroxide, and the outer covering material may contain 50 parts by mass or more and 200 parts by mass or less of the metal hydroxide per 100 parts by mass of the polyolefin resin.

[0029] This makes it possible to provide a cable that mechanically protects the electric wires and metal layer, and provides functions such as flame retardancy and oil resistance, and furthermore, suppresses deterioration of the insulation even when bundled with a wire harness having insulation made of PVC.

[0030] (9) In any of the above (1) to (8), the metal tape may have a laminated structure in which a base film, an adhesive layer, and a thin metal layer are laminated in the above order, the base film may be made of polyethylene terephthalate, and the thin metal layer may contain aluminum or copper.

[0031] This prevents damage to the metal tape and also improves the flexibility of the metal tape.

[0032] (10) In any of the above (1) to (8), the metal tape may be an aluminum foil or a copper foil.

[0033] This prevents damage to the metal tape, maintains the flexibility of the metal tape, and reduces costs.

[0034] (11) In the above (1) or (2), the cable may include two of the electric wires, and the two electric wires may be twisted in a pair.

[0035] (12) In the above (1) or (2), the cable may include two of the electric wires, and the two electric wires may be horizontally wound with a resin tape.

[0036] [Details of the embodiment of the present disclosure] Specific examples of the cable of the present disclosure will be described below with reference to the drawings. In the drawings of the present disclosure, the same reference numerals represent the same or corresponding parts. Furthermore, dimensional relationships such as length, width, thickness, and depth have been appropriately changed for clarity and simplification of the drawings, and do not necessarily represent actual dimensional relationships.

[0037] In this specification, the expression "A to B" means the upper and lower limits of a range (i.e., A or more and B or less), and when no unit is specified for A and a unit is specified only for B, the unit of A and the unit of B are the same.

[0038] In the present disclosure, when one or more numerical values ​​are recited as the lower limit and the upper limit of a numerical range, a combination of any one numerical value recited as the lower limit and any one numerical value recited as the upper limit is also considered to be disclosed. For example, when a1 or more, b1 or more, and c1 or more are recited as the lower limit and a2 or less, b2 or less, and c2 or less are recited as the upper limit, a1 or more and a2 or less, a1 or more and b2 or less, a1 or more and c2 or less, b1 or more and a2 or less, b1 or more and b2 or less, b1 or more and c2 or less, c1 or more and a2 or less, c1 or more and b2 or less, and c1 or more and c2 or less are considered to be disclosed.

[0039] [Embodiment 1] <Cable> A cable according to one embodiment of the present disclosure (hereinafter also referred to as "Embodiment 1") will be described with reference to Fig. 1. Fig. 1 is a schematic cross-sectional view of a cable 10 according to Embodiment 1. As shown in Fig. 1, the cable 10 according to Embodiment 1 includes an electric wire 1, a metal layer 4 covering the electric wire 1, and an outer jacket material 5. The electric wire 1 includes one conductor 2 and an insulating material 3 provided on the outer peripheral surface of the conductor 2. The metal layer 4 includes a vertically attached metal layer 4a formed by vertically attaching a metal tape. The metal tapes partially overlap in the width direction of the metal tapes to form an overlapping portion, and the width of the overlapping portion is 1 / 20 to 1 / 3 of the width of the metal tape.

[0040] <Electric Wire> As shown in FIG. 1 , in a cable 10 of the first embodiment, an electric wire 1 includes one conductor 2 and an insulating material 3 provided on the outer peripheral surface of the conductor 2 .

[0041] <Conductor> The material of the conductor 2 is preferably a metal material with high conductivity and high mechanical strength. Examples of such metal materials include copper, copper alloys, aluminum, aluminum alloys, nickel, silver, mild steel, steel, and stainless steel. The conductor 2 can be a wire material formed from a single metal material. Alternatively, the conductor 2 can have a multilayer structure in which the wire material is coated with another metal using a technique such as plating. Examples of conductors 2 having a multilayer structure include tin-plated copper wire, nickel-plated copper wire, silver-plated copper wire, copper-plated aluminum wire, and copper-plated steel wire.

[0042] The shape of the conductor 2 is not particularly limited, and any conventionally known shape can be used. Examples of the shape of the conductor 2 include a round wire having a circular cross section, a rectangular wire having a square cross section, a rectangular wire having a rectangular cross section, and a twisted wire formed by twisting together a plurality of wires.

[0043] The average cross-sectional area of ​​the conductor 2 is not particularly limited and can be appropriately selected depending on the application. ２ More than 10 mm ２ It may be less than 0.1 mm ２ More than 10 mm ２ In the present disclosure, the average cross-sectional area of ​​the conductor 2 is measured as follows: One conductor 2 is stretched in a straight line, cut along a plane normal to a first direction connecting one end of the conductor 2 to the other, the cross section is exposed, and the cross-sectional area is measured. For one conductor 2, the conductor 2 is cut along a plane normal to the first direction at any five locations, the cross-sectional areas are measured, and an average value is calculated. The average value corresponds to the average cross-sectional area of ​​the conductor 2.

[0044] <Insulating Material> In the cable 10 of the first embodiment, the insulating material 3 is provided on the outer peripheral surface of the conductor 2 .

[0045] The insulating material 3 may include a polyolefin resin, a phenolic antioxidant, and a copper inhibitor.

[0046] <Polyolefin Resins> Examples of polyolefin resins include polypropylene, polypropylene thermoplastic elastomers, reactor-type polypropylene thermoplastic elastomers, dynamically crosslinked polypropylene thermoplastic elastomers, polyethylene (high-density polyethylene (HDPE), linear low-density polyethylene (LLDPE), low-density polyethylene (LDPE), very low-density polyethylene (VLDPE)), ethylene-propylene copolymers, polymethylpentene, ethylene-vinyl acetate copolymers, ethylene-ethyl acrylate copolymers, ethylene-methyl methacrylate copolymers, ethylene-methyl acrylate copolymers, ethylene-ethyl methacrylate copolymers, ethylene-butyl acrylate copolymers, ethylene-propylene rubber, ethylene-acrylic rubber, ethylene-glycidyl methacrylate copolymers, and polyethylene resins such as ethylene-methacrylic acid copolymers; and ionomer resins in which molecules of ethylene-methacrylic acid copolymers are intermolecularly bonded by metal ions such as sodium or zinc. Examples of polyolefin resins that can be used include those obtained by modifying these resins with maleic anhydride or the like, and those containing epoxy groups, amino groups, or imide groups.

[0047] "High density polyethylene (HDPE)" means a polyethylene having a density of 0.942 g / cm ３ "Linear low density polyethylene (LLDPE)" refers to polyethylene with a density of 0.910 g / cm or more. ３ 0.930g / cm or more ３ "Low density polyethylene (LDPE)" refers to polyethylene obtained by copolymerizing ethylene with an α-olefin, and has a density of less than 0.910 g / cm. ３ 0.930g / cm or more ３ "Very low density polyethylene (VLDPE)" refers to polyethylene having a density of less than 0.870 g / cm and obtained by polymerizing ethylene by high-pressure polymerization. ３ 0.910g / cm or more ３"Polymethylpentene" refers to polyethylene of less than 100% by mass. Examples of "polymethylpentene" include homopolymers of 4-methyl-1-pentene and copolymers of 4-methyl-1-pentene with 3-methyl-1-pentene or other α-olefins. Examples of α-olefins include propylene, butene, pentene, hexene, heptene, octene, vinyl acetate, methyl acrylate, ethyl acrylate, methyl methacrylate, and ethyl methacrylate.

[0048] The polyolefin resin may be used alone or in combination of two or more.

[0049] The polyolefin resin may be polypropylene. Examples of polypropylene include homopolypropylene, random polypropylene, and block polypropylene. Homopolypropylene is a homopolymer of propylene. Examples of random polypropylene include a copolymer of propylene and ethylene or an α-olefin having 4 to 20 carbon atoms. Block polypropylene is a resin composed of a homopolypropylene copolymer as a main component, a random copolymer elastomer as a main component, and an ethylene polymer as an optional component. Among these, the use of block polypropylene or homopolypropylene provides better mechanical strength. Using polypropylene as the olefin resin can further improve the dielectric loss tangent reduction effect and heat resistance of the insulating material 3. In this disclosure, "main component" means the component with the largest content.

[0050] The lower limit of the polyolefin resin content of the insulating material 3 is 98% by mass or more, and may be 99% by mass or more. When the polyolefin resin content is 98% by mass or more, the dielectric loss tangent of the insulating material 3 can be reduced effectively. The upper limit of the polyolefin resin content may be 99.98% by mass or less, and may be 99.99% by mass or less. When the polyolefin resin content is 99.98% by mass or less, the content of antioxidants and the like in the insulating material 3 can be ensured, and the oxidation degradation resistance and heat resistance of the insulating material 3 are further improved. The polyolefin resin content of the insulating material 3 may be 98% by mass or more and 99.99% by mass or less, and may be 99% by mass or more and 99.98% by mass or less. When two or more polyolefin resins are used, the content of the polyolefin resins refers to the total content of the two or more polyolefin resins.

[0051] The insulating material 3 may contain a resin other than a polyolefin-based resin. The insulating material 3 may contain, for example, polytetrafluoroethylene, acrylic resin, fluororubber, or the like as a processability improver in an amount of 0.01% by mass to 2.0% by mass.

[0052] <Phenol-Based Antioxidant> The phenol-based antioxidant has a function of preventing oxidation of polyolefin-based resin, which is easily oxidized. When the insulating material 3 contains a phenol-based antioxidant, oxidative degradation of the polyolefin-based resin can be suppressed.

[0053] The phenolic antioxidant is not particularly limited, and known phenolic antioxidants can be used. Examples of the phenolic antioxidant include 3,9-bis[2-{3-(3-tert-butyl-4-hydroxy-5-methylphenyl)propionyloxy}-1,1-dimethylethyl]-2,4,8,10-tetraoxaspiro[5,5]undecane (e.g., "Sumilizer GA-80" (trademark) manufactured by Sumitomo Chemical Co., Ltd., and "ADEKA STAB AO-80" (trademark) manufactured by ADEKA Corporation), ethylenebis(oxyethylene)bis[3-(5-tert- butyl-hydroxy-m-tolyl)propionate] ("Irganox 245" (trademark) manufactured by BASF Japan Ltd.), triethylene glycol bis[3-(3-tert-butyl-4-hydroxy-5-methylphenyl)propionate] (for example, "ADEKA STAB AO-70" (trademark) manufactured by ADEKA Corporation), 1,3,5-tri(3,5-di-tert-butyl-4-hydroxybenzyl)-1,3,5-triazine-2,4,6(1H,3H ,5H)-trione] (for example, "ADK STAB AO-60" (trademark) manufactured by ADEKA Corporation), 4,4'-thiobis(6-tert-butyl-m-cresol) (for example, "SUMIRAIZER WX-R" (trademark) manufactured by Sumitomo Chemical Co., Ltd.), 4,4'-butylidenebis(3-methyl-6-tert-butylphenol) (for example, "NOCRACK NS-30" (trademark) manufactured by Ouchi Shinko Chemical Industry Co., Ltd., "ADK STAB AO-4 ... Examples of such an olefin include o-bis(3-methyl-6-tert-butyl)phenol (e.g., "Nocrac 300" (trademark) manufactured by Ouchi Shinko Chemical Industry Co., Ltd.), 1,1,3-tris-(2-methyl-4-hydroxy-5-tert-butylphenyl)butane (e.g., "ADEKA STAB AO-30" (trademark) manufactured by ADEKA Corporation), and bis[3,3-bis(3-tert-butyl-4-hydroxyphenyl)butyrate]ethylene (e.g., "HOSTANOX O3" (trademark) manufactured by Clariant Chemicals).

[0054] The phenol-based antioxidants may be used alone or in combination of two or more.

[0055] In the insulating material 3, the blending amount of the phenolic antioxidant per 100 parts by mass of the polyolefin-based resin is 0.01 parts by mass or more and 0.5 parts by mass or less. When the blending amount of the phenolic antioxidant is 0.01 parts by mass or more, the antioxidant effect of the polyolefin-based resin is further improved. When the blending amount of the phenolic antioxidant is 0.5 parts by mass or less, an increase in the dielectric dissipation factor of the insulating material 3 due to the antioxidant can be suppressed, and the power transmission characteristics of the cable 10 can be further improved. The lower limit of the blending amount of the phenolic antioxidant per 100 parts by mass of the polyolefin-based resin is 0.01 parts by mass or more, or may be 0.010 parts by mass or more, or 0.05 parts by mass or more. The upper limit of the blending amount of the phenolic antioxidant per 100 parts by mass of the polyolefin-based resin is 0.5 parts by mass or less, or may be 0.3 parts by mass or less. The blending amount of the phenolic antioxidant per 100 parts by mass of the polyolefin-based resin may be 0.05 parts by mass or more and 0.3 parts by mass or less. When two or more types of phenolic antioxidants are used, the blending amount of the phenolic antioxidants means the total content of the two or more types of phenolic antioxidants.

[0056] The insulating material 3 may contain an antioxidant other than a phenol-based antioxidant. For example, the insulating material 3 may contain a sulfur-based antioxidant excluding a sulfur-containing phenol-based antioxidant.

[0057] <Copper Damage Inhibitor> The copper damage inhibitor stabilizes copper ions by chelate formation and suppresses copper ion-induced deterioration of the resin contained in the insulating material 3, i.e., copper damage. When the insulating material 3 further contains a copper damage inhibitor, copper damage can be suppressed, and oxidative degradation of the polyolefin resin can be suppressed.

[0058] The copper inhibitor is not particularly limited, and known copper inhibitors can be used. Examples of copper inhibitors include salicylic acid derivatives, phthalic acid derivatives, composites of triazole compounds, and aromatic secondary amine compounds. Examples of salicylic acid derivatives include NN'-bis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionyl]hydrazine (such as "Irganox MD1024" (trademark) manufactured by BASF Japan), 3-(N-salicyloyl)amino-1,2,4-triazole ("ADK STAB CDA-1" manufactured by ADEKA), and decamethylenedicarboxylic acid disalicyloylhydrazide ("ADK STAB CDA-6" manufactured by ADEKA). An example of a composite of triazole compounds is a composite containing 2-hydroxy-N-1H-1,2,4-triazol-3-ylbenzamide as the main component ("ADEKA STAB CDA-1M" (trademark) manufactured by ADEKA Corporation). An example of an aromatic secondary amine compound is N,N'-di-2-naphthyl-p-phenylenediamine ("NOCRAC White" (trademark) manufactured by Ouchi Shinko Chemical Industry Co., Ltd.).

[0059] The copper inhibitor may be used alone or in combination of two or more.

[0060] In the insulating material 3, the amount of copper inhibitor blended per 100 parts by mass of polyolefin-based resin is 0.01 parts by mass or more and 0.5 parts by mass or less. When the amount of copper inhibitor blended is 0.01 parts by mass or more, the copper inhibitor effect is further improved. When the amount of copper inhibitor blended is 0.5 parts by mass or less, the occurrence of so-called bloom, in which the copper inhibitor precipitates and crystallizes on the surface of the insulating material 3, is suppressed, and the quality of the insulating material 3 is easily ensured. The lower limit of the amount of copper inhibitor blended per 100 parts by mass of polyolefin-based resin may be 0.010 parts by mass or more, or may be 0.05 parts by mass or more. The upper limit of the amount of copper inhibitor blended per 100 parts by mass of polyolefin-based resin may be 0.3 parts by mass or less. The amount of copper inhibitor blended per 100 parts by mass of polyolefin-based resin may be 0.05 parts by mass or more and 0.3 parts by mass or less. When two or more copper inhibitors are used, the amount of copper inhibitors mentioned above means the total content of the two or more copper inhibitors.

[0061] The insulating material 3 may contain a metal inhibitor other than the copper inhibitor.

[0062] <Other Components> In addition to the polyolefin resin, phenolic antioxidant, and copper inhibitor, the insulating material 3 may contain other components, such as processability improvers, lubricants, pigments, etc., in a range of 0.01 mass % or more and 2.0 mass % or less.

[0063] The processability improver is used to improve the extrusion processability of the insulating material 3. Examples of the processability improver include polytetrafluoroethylene, acrylic resin, and fluorine rubber.

[0064] The lubricant improves the releasability of the insulating material 3 from a mixer or an extruder. Examples of lubricants include paraffin, stearic acid, zinc stearate, and fatty acid amide.

[0065] The pigment is used to color the insulating material 3. As the pigment, various known pigments can be used, for example, titanium oxide.

[0066] When a high frequency electric field of 10 GHz is applied, the dielectric loss tangent of the insulating material 3 is 3.0×10 －４ This makes it possible to sufficiently improve the effect of reducing transmission loss.

[0067] The upper limit of the relative dielectric constant of the insulating material 3 may be 2.5 or less, or may be 2.3 or less. When the relative dielectric constant of the insulating material 3 is 2.5 or less, the effect of reducing transmission loss can be sufficiently improved.

[0068] The above "dielectric loss tangent" and "relative dielectric constant" are values ​​measured according to a method conforming to JIS-R1641 (2007).

[0069] The lower limit of the average thickness of the insulating material 3 may be 50 μm or more, or 100 μm or more. When the average thickness of the insulating material 3 is 50 μm or more, sufficient insulation tends to be ensured. The upper limit of the average thickness of the insulating material 3 may be 1500 μm or less, or 1000 μm or less. When the average thickness of the insulating material 3 is 1500 μm or less, the volume efficiency of the cable 10 formed using the electric wire can be improved. The average thickness of the insulating material 3 may be 50 μm or more and 1500 μm or less, or 100 μm or more and 1000 μm or less.

[0070] In the present disclosure, the method for measuring the average thickness of the insulating material 3 is as follows: One conductor 2 is stretched in a straight line, and the conductor 2 is cut along a plane normal to a first direction connecting one end of the conductor 2 to the other, exposing a cross section. The thickness of the insulating material 3 is measured at three arbitrary locations on the cross section, and the average of these is calculated to obtain a first average value. For one conductor 2, the conductor 2 is cut along a plane normal to the first direction at five arbitrary locations, and the first average values ​​are measured, and the average of these is calculated to obtain a second average value. The second average value corresponds to the average thickness of the insulating material 3.

[0071] <Metal Layer> <Longitudinal Metal Layer> The cable 10 of embodiment 1 includes a metal layer 4 that covers the electric wire 1. In the cable 10 of embodiment 1, the metal layer 4 is made of a longitudinally attached metal layer 4a that is formed by vertically attaching a metal tape. As shown in Fig. 3 , the metal tapes partially overlap each other in the width direction of the metal tape to form an overlapping portion 16, and the width W2 of the overlapping portion 16 is 1 / 20 to 1 / 3 of the width W1 of the metal tape.

[0072] In the present disclosure, "vertical placement" means that the metal tape is wrapped around the electric wire 1 along the extending direction X, as shown in Fig. 3. In the present disclosure, the width direction of the metal tape means the direction perpendicular to the extending direction of the metal tape.

[0073] The width W1 of the metal tape can be appropriately selected depending on the outer circumferential length of the electric wire 1 to be covered and the width W2 of the overlapping portion where the metal tapes overlap. The lower limit of the width W1 of the metal tape may be 2 mm or more, or 3 mm or more. The upper limit of the width W1 of the metal tape may be 30 mm or less, 25 mm or less, or 20 mm or less. The width W1 of the metal tape may be 2 mm or more and 30 mm or less, 3 mm or more and 25 mm or less, or 2 mm or more and 20 mm or less. In the present disclosure, the width W1 of the metal tape means the shortest distance between a pair of first and second side edges extending in the extension direction of the metal tape.

[0074] The metal tapes overlap each other in the width direction to form an overlapping portion, and the width W2 of the overlapping portion is not particularly limited as long as it is 1 / 20 to 1 / 3 of the width W1 of the metal tape. The width W2 of the overlapping portion may be, for example, 0.01 mm to 10 mm, or 0.015 mm to 8 mm. When the width W2 of the overlapping portion is 0.01 mm or more, the effect of suppressing deterioration of the insulating material 3 is improved. When the width W2 of the overlapping portion is 10 mm or less, the cable is easy to bend and costs are reduced.

[0075] The metal tape may have a laminated structure in which a base film, an adhesive layer, and a thin metal layer are laminated in the above order. The metal tape can have a laminated structure in which an adhesive layer and a thin metal layer are laminated in the above order on one main surface of a tape-shaped base film.

[0076] The metal tape, which has an adhesive applied to the surface of the base film opposite the thin metal layer, is wound around the electric wire and then fixed to the electric wire with the adhesive, which is preferable because the metal tape will not peel off from the electric wire.

[0077] The substrate film may be made of polyethylene terephthalate and may have a thickness of 1 μm or more and 20 μm or less.

[0078] The material of the adhesive layer is not particularly limited as long as it can bond the base film and the metal foil, and any conventionally known material can be used. Examples of the material for the adhesive layer include acrylic resin, epoxy resin, urethane resin, polyolefin resin, cyanoacrylate resin, silicone resin, styrene-butadiene rubber, phenol resin, nitrile rubber, polyamide resin, polyvinyl acetate resin, and polyvinyl alcohol resin.

[0079] The thin metal layer may be made of aluminum or copper. The thin metal layer may be an aluminum foil or a copper foil. The thickness of the thin metal layer made of aluminum foil or copper foil may be 5 μm or more and 20 μm or less.

[0080] The metal tape may be one in which a metal vapor-deposited layer is formed on a base film. In this case, the thin metal layer is a metal vapor-deposited layer. The thickness of the thin metal layer made of a metal vapor-deposited layer may be 0.5 μm or more and 2 μm or less.

[0081] When the metal tape has a laminated structure including a base film and a thin metal layer, the surface of the metal tape that faces the electric wire 1 when the metal tape is wrapped around the electric wire 1 may be the exposed surface on the base film side or the exposed surface on the thin metal layer side.

[0082] The metal tape may have a single layer structure made of aluminum foil or copper foil, in which case the thickness of the aluminum foil or copper foil may be 0.1 μm or more and 20 μm or less.

[0083] 1 , the cable 10 of the first embodiment can further include an outer covering 5 that covers the metal layer 4. The outer covering 5 can protect the electric wires 1 and the metal layer 4 and can impart functions such as flame retardancy and oil resistance. Furthermore, even when the cable 10 is bundled with a wire harness having an insulating material made of PVC, deterioration of the insulating material can be further suppressed.

[0084] <Polyolefin-based resin> The outer covering material 5 may contain a polyolefin-based resin and a metal hydroxide. The polyolefin-based resin of the outer covering material 5 may be any of the polyolefin-based resins described above as the polyolefin-based resin used in the insulating material 3. One type of polyolefin-based resin may be used, or two or more types may be used. The polyolefin-based resin of the outer covering material 5 and the polyolefin-based resin of the insulating material 3 may be the same or different.

[0085] The lower limit of the polyolefin resin content in the outer covering material 5 may be 33% by mass or more, or 35% by mass or more. When the polyolefin resin content is 33% by mass or more, it is possible to maintain good mechanical properties, oil resistance, etc. of the outer covering material 5. The upper limit of the polyolefin resin content may be 67% by mass or less, or 60% by mass or less. When the polyolefin resin content is 67% by mass or less, good flame retardancy is achieved. Furthermore, when the cable of embodiment 1 is bundled with a wire harness having an insulating material made of PVC, deterioration of the cable insulating material is further suppressed. When two or more polyolefin resins are used, the content of the polyolefin resins refers to the total content of the two or more polyolefin resins.

[0086] The outer covering material 5 may contain a resin other than a polyolefin-based resin. For example, the outer covering material 5 may contain polytetrafluoroethylene, acrylic resin, fluororubber, or the like as a processability improver in an amount of 0.1% by mass to 5.0% by mass.

[0087] <Metal hydroxide> Metal hydroxide undergoes an endothermic dehydration reaction at high temperatures of 200°C or higher, suppressing combustion of materials containing the metal hydroxide. Furthermore, when the jacket material contains a metal hydroxide, deterioration of the cable insulation is further suppressed when the cable of embodiment 1 is bundled with a wire harness having an insulation material made of PVC. As the metal hydroxide, at least one selected from the group consisting of magnesium hydroxide and aluminum hydroxide can be used.

[0088] In the outer covering material 5, the amount of metal hydroxide blended per 100 parts by mass of polyolefin-based resin may be 50 parts by mass or more and 200 parts by mass or less, or may be 80 parts by mass or more and 180 parts by mass or less. When two or more types of metal hydroxide are used, the blending amount of the metal hydroxide means the total content of the two or more types of metal hydroxide.

[0089] <Other Components> In addition to the polyolefin resin and metal hydroxide, the outer covering material 5 may contain other components such as halogen-based flame retardants, phosphorus-based flame retardants (red phosphorus, phosphate esters, sodium hypophosphite, etc.), intumescent flame retardants, flame retardant assistants (antimony trioxide, melamine cyanurate, zinc borate, zinc oxide, zinc hydroxystannate, etc.), inorganic fillers (calcium carbonate, talc, silica, clay, etc.), pigments, lubricants, antioxidants, copper inhibitors, ultraviolet absorbers, light stabilizers, etc.

[0090] [Embodiment 2] A cable according to another embodiment of the present disclosure (hereinafter also referred to as "Embodiment 2") will be described with reference to Figs. 1 and 4. Fig. 1 is a schematic cross-sectional view of a cable 10 according to Embodiment 2. As shown in Fig. 1, the cable 10 according to Embodiment 2 includes one electric wire 1 and a metal layer 4 covering the electric wire 1. The electric wire 1 includes one conductor 2 and an insulating material 3 provided on the outer peripheral surface of the conductor 2. The metal layer 4 includes a horizontally wound metal layer 4b formed by horizontally winding a metal tape. The metal tapes partially overlap each other in the width direction to form an overlapping portion, and the width W2 of the overlapping portion is 1 / 5 to 1 / 2 of the width W1 of the metal tape, and the twist angle of the metal tape is greater than 0° and less than 80°. The cable 10 according to Embodiment 2 suppresses deterioration of the insulating material 3 even when bundled with a wire harness having an insulating material made of PVC. The cable 10 of the second embodiment can have the same configuration as that of the first embodiment, except that it includes a horizontal metal layer 4b instead of the vertical supporting metal layer 4a of the first embodiment. The horizontal metal layer 4b will be described below.

[0091] <Horizontal Wound Metal Layer> In embodiment 2, the metal layer 4 is a horizontally wound metal layer 4b formed by horizontally winding a metal tape. As shown in Fig. 3 , the metal tapes partially overlap each other in the width direction of the metal tape to form an overlapping portion 16, the width W2 of the overlapping portion 16 is from 1 / 5 to 1 / 2 of the width W1 of the metal tape, and the turning angle A of the metal tape is greater than 0° and less than 80°.

[0092] In the present disclosure, horizontal winding means that a metal tape is wound spirally around the outer periphery of the electric wire 1, as shown in Fig. 4. The metal tape may have the same configuration as that of the first embodiment.

[0093] The metal tapes overlap each other in the width direction to form an overlapping portion, and the width W2 of the overlapping portion is not particularly limited as long as it is between 1 / 5 and 1 / 2 of the width W1 of the metal tape. The width W2 of the overlapping portion may be, for example, between 0.4 mm and 15 mm, or between 0.6 mm and 13 mm. When the width W2 of the overlapping portion is 0.4 mm or more, the effect of suppressing deterioration of the insulating material 3 is improved. When the width W2 of the overlapping portion is 15 mm or less, the cable is easy to bend and costs are reduced.

[0094] The turning angle of the metal tape is more than 0° and not more than 80°, and may be not less than 7° and not more than 80°. In the present disclosure, the turning angle of the metal tape means the acute angle A formed by the extending direction X1 of the electric wire 1 and the side edge of the metal tape when the state in which the metal tape is wound laterally around the electric wire 1 is viewed in a plane as shown in Figure 4.

[0095] [Embodiment 3] A cable according to another embodiment of the present disclosure (hereinafter also referred to as "Embodiment 3") will be described with reference to Figure 2. Figure 2 is a schematic cross-sectional view of a cable 10 according to Embodiment 3. The cable 10 according to Embodiment 3 can have the same configuration as Embodiment 1 or 2, except that it further includes a metal braid 6 that covers the surface of the vertical laying metal layer 4a or the horizontal winding metal layer 4b opposite to the surface facing the electric wire 1. The metal braid 6 is disposed between the metal layer 4 and the jacket material 5. The cable 10 of Embodiment 3 further suppresses deterioration of the insulation material 3. The metal braid 6 will be described below.

[0096] The material of the metal braid constituting the metal braid 6 is preferably a metal material having high electrical conductivity and high mechanical strength. Examples of such metal materials include copper and copper alloys. The metal braid can be formed by braiding a wire material formed from a single metal material into a tubular shape. A multilayer structure in which the wire material is further coated with another metal can also be used. Examples of wire materials having a multilayer structure include tin-plated copper wire, nickel-plated copper wire, silver-plated copper wire, copper-plated aluminum wire, and copper-coated steel wire.

[0097] [Embodiment 4] A cable according to another embodiment of the present disclosure (hereinafter also referred to as "Embodiment 4") will be described with reference to Figures 5A and 5B. Figure 5A is a schematic cross-sectional view of an example of a cable 10 according to Embodiment 4. Figure 5A shows a configuration in which two electric wires are twisted together, a so-called twisted pair. In Figure 5A, the dashed line indicates the outer edge 4c of the metal layer 4 that covers the electric wires that are not exposed in the cross section. Figure 5B is a schematic cross-sectional view of another example of a cable according to Embodiment 4. Figure 5B shows a so-called twin-core parallel configuration in which two electric wires are arranged in parallel.

[0098] A cable 10 of a fourth embodiment includes two electric wires 1 and a metal layer 4 covering the two electric wires 1. The electric wire 1 includes a conductor 2 and an insulating material 3 provided on the outer surface of the conductor 2. The metal layer 4 is composed of a vertically laid metal layer 4a or a horizontally wound metal layer 4b. The two electric wires 1 covered with the metal layer 4 have a resin tape 7 (e.g., PET tape) wrapped horizontally around the metal layer 4 to fix the relative positions of the two electric wires, and an outer sheath material 5 is provided on the outside of the resin tape 7. As shown in FIG. 5A , when the two electric wires are twisted in a pair, wrapping the resin tape 7 around the metal layer 4 of the twisted pair electric wires 1 prevents the twist from loosening and the relative positions from changing even when the cable is bent. As shown in FIG. 5B , when the two electric wires are arranged parallel to each other, a resin tape 7 is wrapped around the two electric wires to fix their positions.

[0099] Although two electric wires 1 are shown in FIGS. 5A and 5B, the number of electric wires 1 is not particularly limited, and any number equal to or greater than two can be appropriately set depending on the application.

[0100] [Embodiment 5] A cable according to another embodiment of the present disclosure (hereinafter also referred to as "Embodiment 5") will be described with reference to Figs. 6A and 6B. Fig. 6A is a cross-sectional view of an example of a cable 10 according to Embodiment 5. Fig. 6A shows a configuration in which two electric wires are twisted together, a so-called twisted pair. Fig. 6B is a schematic cross-sectional view of another example of a cable according to Embodiment 5. Fig. 6B shows a so-called twin-core parallel configuration in which two electric wires are arranged in parallel.

[0101] The cable 10 according to the fifth embodiment can have the same configuration as that of the fourth embodiment, except that it further includes a metal braid 6 covering the outer periphery of the vertically wound metal layer 4 a or the outer periphery of the horizontally wound metal layer 4 b. Details of the metal braid 6 are as described in the third embodiment.

[0102] [Embodiment 6] A cable according to another embodiment of the present disclosure (hereinafter also referred to as "Embodiment 6") will be described with reference to Figures 7 and 8. Figures 7 and 8 are schematic cross-sectional views of a cable 10 according to Embodiment 6. The cable 10 according to Embodiment 7 can have the same configuration as Embodiment 1 or 2, except that it has a first group of electric wires 1 consisting of two or more electric wires 1, and the first group of electric wires is collectively covered with a metal layer 4. Hereinafter, a structure in which a first group of electric wires consisting of two or more electric wires 1 is collectively covered with a metal layer 4 will also be referred to as a "first structure." In the case of Figure 7, it is also preferable to wrap a resin tape 7 on the metal layer 4. In particular, when the metal layer 4 is vertically attached, it is preferable to hold the vertically attached wrapped tape in place with the resin tape 7 to prevent it from unfolding.

[0103] 7 and 8 show a wire group in which the first structure is composed of two wires 1, but the number of wires 1 included in one wire group is not particularly limited and may include two or more depending on the application. In FIG. 7, one cable 10 includes one first structure, but the number of first structures included in one cable 10 is not particularly limited and may include two or more first structures depending on the application. For example, as shown in FIG. 8, one cable 10 may include two first structures.

[0104] [Embodiment 7] A cable according to another embodiment of the present disclosure (hereinafter also referred to as "Embodiment 7") will be described with reference to Figures 9 and 10. Figures 9 and 10 are schematic cross-sectional views of a cable 10 according to Embodiment 7. The cable 10 according to Embodiment 7 can have the same configuration as that of Embodiment 6, except that it further includes a metal braid 6 that covers the surface of the vertical metal layer 4a or the horizontal metal layer 4b opposite to the surface facing the electric wire 1. Details of the metal braid 6 are as described in Embodiment 3.

[0105] The present embodiment will be described in more detail with reference to examples, although the present embodiment is not limited to these examples.

[0106] [Test for Evaluating Deterioration Suppression of Insulating Material] <Preparation of Test Sample> In order to evaluate the effect of the metal layer in suppressing deterioration of the insulating material, a test sample was prepared by the following procedure.

[0107] Seven tin-plated annealed copper conductors (AWG26) with a diameter of 0.16 mm and a single strand were prepared as conductors. A 0.36 mm thick insulating material was formed on the outer surface of the conductor by extrusion molding to obtain electric wires. The composition of the insulating material is shown in the "Insulating Material" column in Tables 1 and 2. The "Polyolefin Resin" listed in the "Insulating Material" column in Tables 1 and 5 is block polypropylene, the "Antioxidant" is a hindered phenol-based antioxidant, and the "Copper Inhibitor" is a copper inhibitor with a hydrazide structure. For all samples, the insulating material was made using polyolefin resin, antioxidant, and copper inhibitor as raw materials, with no other components used as raw materials. For each sample, one or two electric wires were prepared. When two electric wires were prepared, the two electric wires were twisted together to form a twisted pair.

[0108] A metal tape consisting of aluminum foil (corresponding to a thin metal layer) bonded to a PET (polyethylene terephthalate) substrate was wrapped around the outer periphery of the electric wire to form a vertically attached metal layer or a horizontally wound metal layer. The width W1 of the metal tape and the thickness of the aluminum foil (corresponding to a thin metal layer) are shown in the "Width W1 of Metal Tape" and "Thickness of Thin Metal Layer" columns in Tables 2 and 6. The metal tape coating method for each sample is shown in the "Coating Method" column in Tables 2 and 6. "Vertical" indicates that the metal tape was wrapped vertically around the outer periphery of the electric wire. "Horizontal" indicates that the metal tape was wrapped horizontally around the outer periphery of the electric wire. "Individual" indicates that each electric wire was coated with metal tape. "Batch" indicates that two electric wires were collectively coated with metal tape. The width W2 of the overlapping portion of the metal tape when the metal tape is wound vertically or horizontally, and the ratio W2 / W1 of the width W2 of the overlapping portion to the width W1 of the metal tape, are as shown in the "Width W2 of the overlapping portion" and "W2 / W1" columns in Tables 2 and 6.

[0109] In Tables 2 and 6, for samples with "Yes" in the "Metal Braid" column, the longitudinally-wound metal layer or the transversely-wound metal layer was covered with a metal braid. The metal braid was made of tin-plated annealed copper with a wire diameter of 0.1 mm and a thickness of 0.4 mm. In the case of a single electric wire, two electric wires covered with a metal tape were twisted together, and the twisted pair was covered with a metal braid.

[0110] Further, a 0.6 mm thick outer jacket material was extrusion coated on the outside of the metal layer or metal braid to obtain test samples. The composition of the outer jacket material is as shown in the "Outer Jacket Material" column of Tables 3 and 7. The "polyolefin resin" listed in the "Outer Jacket Material" column of Tables 3 and 7 is block polypropylene. In all samples, the outer jacket material was a mixture of polyolefin resin and Mg(OH) ２ , Al(OH ３ When there was only one electric wire, two electric wires covered with a metal tape were twisted together, and an outer jacket was then applied around the twisted pair of electric wires.

[0111]

[0112]

[0113]

[0114]

[0115]

[0116]

[0117]

[0118]

[0119] [Deterioration Suppression Evaluation Test] A test sample was brought into contact with PVC at 100°C, and the time until the appearance of the insulating material became abnormal was measured. The longer the time until the appearance of the insulating material became abnormal, the more the deterioration of the insulating material was suppressed. The specific test method was as follows.

[0120] 11A and 11B are cross-sectional views of a test structure 11 used in a degradation suppression evaluation test for insulating materials.

[0121] 11A is a cross-sectional view of a test structure 11 when using a test sample 12 with a single electric wire. As shown in FIG. 11A, the test structure 11 is formed by bundling the test sample 12 and six PVC-coated electric wires 14 arranged so as to surround the test sample 12 with PVC tape 15.

[0122] 11B is a cross-sectional view of a test structure when a test sample having two electric wires is used. As shown in FIG. 11B, the test structure 11 is made by bundling a test sample 12 and six PVC-coated electric wires 14 that are tightly attached to the periphery of the test sample 12 with PVC tape 15.

[0123] The PVC-coated wire 14 consists of a conductor 2 (a twisted wire of 65 tin-plated soft copper single conductors, each 0.32 mm in diameter, with a diameter of 3.0 mm) and a PVC insulating material 13 (diameter 4.6 mm) made of cross-linked polyvinyl chloride with a thickness of 0.8 mm that coats the outer periphery of the conductor 2.

[0124] The PVC tape used for the test structure 11 was VTA tape (thickness: 0.135 mm, width: 19 mm) manufactured by Yazaki Corporation. The VTA tape was half-wrapped to bundle the test sample 12 and the PVC-coated electric wire 14 together to form the test structure 11.

[0125] In the degradation suppression evaluation test, multiple test structures 11 were placed in an oven at 100°C and removed after 1000 hours, 2000 hours, and 3000 hours. Next, the test structures 11 were disassembled, the electric wires were removed, and the electric wires were wound halfway around the circumferential direction of the self-diameter mandrel. Here, the self-diameter mandrel means a mandrel with the same diameter as the electric wire. The length of the outer periphery of the electric wire wound around the self-diameter mandrel was elongated by 1.5 times the length of the central portion of the electric wire.

[0126] In the degradation inhibition evaluation test, the insulation of the electric wire wound around the self-diameter mandrel was visually observed for appearance abnormalities such as cracks, fissures, and exposed conductors, and the time when an appearance abnormality was observed was recorded as the appearance abnormality appearance time. The results are shown in the "Time" column of "Degradation Inhibition Evaluation Test" under "Evaluation" in Tables 4 and 8. In Tables 4 and 8, ">3000" indicates that no appearance abnormality had occurred after 3000 hours. In Tables 4 and 8, "<1000" indicates that an appearance abnormality had occurred after 1000 hours. The longer the appearance abnormality appearance time, the greater the effect of inhibiting the degradation of the insulation. For samples marked with "-" in the corresponding column, the degradation inhibition evaluation test was not performed.

[0127] [Heat Aging Test] Seven stranded wires (AWG26) made of tin-plated annealed copper with a diameter of 0.16 mm and consisting of solid conductors were prepared. A 0.36 mm thick insulating material was formed on the outer surface of the conductor by extrusion molding to obtain an electric wire. The length of the electric wire was 350 mm. Each sample electric wire was subjected to a heat aging test based on the ISO 6722 standard (Class B). Long-term and short-term aging tests were performed as heat aging tests. The test conditions for each test were as follows:

[0128] <Long-term aging test> After heating the electric wire in a thermostatic chamber at 100°C for 3000 hours, it was removed and kept at room temperature for 16 hours, and then wound three times at room temperature around a mandrel with a diameter five times the diameter of the electric wire. If there were no cracks in the insulation material and no dielectric breakdown occurred in a voltage resistance test (1 kV x 1 minute) in which the wire was immersed in salt water, the test was considered to have passed.

[0129] <Short-term aging test> After heating in a thermostatic chamber at 125°C for 240 hours, the wires and cables were removed and held at room temperature for 16 hours, and then wound three times around a mandrel with a diameter five times the diameter of the wires and cables at -25°C. If there were no cracks in the insulating material and no dielectric breakdown occurred in a voltage resistance test (1 kV x 1 minute) in which the material was immersed in salt water, the material was judged to have passed.

[0130] The results are shown in the "Heat Aging Resistance" column under "Evaluation" in Tables 1 and 2. In Tables 1 and 2, "A" indicates that both the long-term aging test and the short-term aging test were passed, and "B" indicates that at least one of the long-term aging test and the short-term aging test was failed. Samples marked with "-" in the corresponding column were not subjected to the heat aging test.

[0131] [Flexibility Test] For each sample, a flexibility test sample was prepared by covering the test sample 12 shown in Figures 11A and 11B with resin tape 7. A compression test jig was attached to a tensile tester, and the flexibility test sample was fixed to the jig. The reaction force when bent at a bending radius of 25 mm was measured and evaluated. The evaluation criteria for bending performance were as follows: a bending reaction force of 1 N or less was considered pass, and a bending reaction force of more than 1 N was considered fail.

[0132] The results are shown in the "Flexibility" column of "Evaluation" in Tables 4 and 8. In Tables 4 and 8, "A" indicates passing, and "B" indicates failing. For samples marked with "-" in the column, the flexibility test was not performed.

[0133] Abrasion Resistance Test: Test specimen 12 shown in Fig. 11A and Fig. 11B was prepared for each sample. The strength of the outer covering material was measured by a scrape abrasion test based on the ISO 6722 standard. The test was performed with a needle diameter of 0.45 mm, a load of 7 N, and an operating speed of 55 cycles / min. A test that could be repeated 200 times or more until the metal braid or metal tape was exposed was deemed to have passed.

[0134] The results are shown in the "Wear Resistance" column of "Evaluation" in Tables 4 and 8. In Tables 4 and 8, "A" indicates passing, and "B" indicates failing.

[0135] [Evaluation of Insulating Material] <Preparation of Test Insulating Sheet> In order to measure the dielectric loss tangent and relative dielectric constant of the insulating material used in the above-mentioned test sample 12 and to perform a heat aging resistance test, a test insulating sheet was prepared by the following procedure.

[0136] A resin composition for insulating material was obtained by mixing a polyolefin resin, an antioxidant, and a copper inhibitor in the formulation shown in the "Insulating Material" column of Tables 1 and 2. The resin composition for insulating material was press-molded to prepare an insulating sheet for testing. The press-molding conditions were that the mixture was preheated at 180°C for 5 minutes, then pressurized at that temperature and held for 5 minutes.

[0137] <Measurement of dielectric loss tangent and relative permittivity> The dielectric loss tangent and relative permittivity of the test insulating sheet were measured when a high-frequency electric field of 10 GHz was applied according to a method conforming to JIS-R1641 (2007). The measurement was performed three times, and the average values ​​were calculated. The results are shown in the "dielectric loss tangent" and "relative permittivity" columns of Tables 1 and 2.

[0138] [Discussion] Samples 1 to 12 and 101 to 112 correspond to examples. It was confirmed that Samples 1 to 12 and 101 to 112 did not increase the dielectric loss tangent of the insulating material and were highly effective in suppressing deterioration of the insulating material.

[0139] Samples 1-1 to 1-9 and samples 2-1 to 2-8 correspond to comparative examples. Samples 1-1, 1-3, 2-1, and 2-3 were evaluated as "B" in the heat aging resistance test and failed, so other tests were not performed. Samples 1-2, 1-4, 2-2, and 2-4 were not subjected to other tests because they had poor deterioration suppression effects. Samples 1-5, 1-6, 1-7, 2-5, and 2-6 had a dielectric loss tangent of 3.0 × 10 －４Since Samples 1-8, 1-9, 2-7, and 2-8 were evaluated as "B" in the flexibility test and failed, the degradation inhibition and heat aging resistance tests were not performed.

[0140] Although the embodiments and examples of the present disclosure have been described above, it is intended from the beginning that the configurations of the above-described embodiments and examples may be appropriately combined and modified in various ways. The embodiments and examples disclosed herein are illustrative in all respects and should not be considered limiting. The scope of the present invention is defined by the claims, not by the above-described embodiments and examples, and is intended to include meanings equivalent to the claims and all modifications within the scope of the claims.

[0141] REFERENCE SIGNS LIST 1 Electric wire, 2 Conductor, 3 Insulation material, 4 Metal layer, 4a Vertically-wound metal layer, 4b Horizontally-wound metal layer, 4c Outer edge of metal layer, 5 Outer jacket material, 6 Metal braid, 7 Resin tape, 10 Cable, 11 Test structure, 12 Test sample, 13 PVC insulation material, 14 PVC-coated wire, 15 PVC tape, 16 Overlap portion.

Claims

1. A cable comprising an electric wire and a metal layer covering the electric wire, The electric wire includes a conductor and an insulating material provided on the outer surface of the conductor. The insulating material comprises a polyolefin resin, a phenolic antioxidant, and a copper damage inhibitor. The content of the polyolefin resin in the insulating material is 98% by mass or more. The insulating material contains, per 100 parts by mass of the polyolefin resin, 0.01 to 0.5 parts by mass of the phenolic antioxidant and 0.01 to 0.5 parts by mass of the copper damage inhibitor, and has a dielectric loss tangent of 3.0 × 10⁻¹⁰ at 10 GHz. －４ The following: The aforementioned metal layer includes a longitudinally attached metal layer formed by longitudinally attaching a metal tape. The metal tape partially overlaps in the width direction of the metal tape to form an overlapping portion. The width of the overlapping portion is 1 / 20 or more and 1 / 3 or less of the width of the metal tape, in a cable.

2. A cable comprising an electric wire and a metal layer covering the electric wire, The electric wire includes a conductor and an insulating material provided on the outer surface of the conductor. The insulating material comprises a polyolefin resin, a phenolic antioxidant, and a copper damage inhibitor. The content of the polyolefin resin in the insulating material is 98% by mass or more. The insulating material contains, per 100 parts by mass of the polyolefin resin, 0.01 to 0.5 parts by mass of the phenolic antioxidant and 0.01 to 0.5 parts by mass of the copper damage inhibitor, and has a dielectric loss tangent of 3.0 × 10⁻¹⁰ at 10 GHz. －４ The following: The aforementioned metal layer includes a horizontally wound metal layer formed by horizontally winding a metal tape, The metal tape partially overlaps in the width direction of the metal tape to form an overlapping portion. The width of the overlapping portion is 1 / 5 or more and 1 / 2 or less of the width of the metal tape. The cable has a rotation angle of the metal tape that is greater than 0° and less than or equal to 80°.

3. The cable includes a plurality of the aforementioned wires, The cable according to claim 1 or claim 2, wherein the metal layer covers each of the electric wires.

4. The cable has a first group of wires consisting of two or more of the aforementioned wires. The cable according to claim 1 or claim 2, wherein the metal layer covers the first group of electric wires collectively.

5. The cable according to claim 1 or claim 2, further comprising a metal braid covering the surface of the metal layer opposite to the surface facing the electric wire.

6. The aforementioned metal tape includes a thin layer of metal, The cable according to claim 1 or claim 2, wherein the thickness of the metal thin layer is 0.1 μm or more and 20 μm or less.

7. The cable according to claim 1 or claim 2, wherein the polyolefin resin is a polypropylene resin.

8. The cable further comprises an outer sheath material that covers the metal layer, The aforementioned outer covering material comprises a polyolefin resin and a metal hydroxide. The aforementioned metal hydroxide is at least one selected from the group consisting of magnesium hydroxide and aluminum hydroxide. The cable according to claim 1 or claim 2, wherein the outer sheath material contains 50 to 200 parts by mass of the metal hydroxide per 100 parts by mass of the polyolefin resin.

9. The aforementioned metal tape includes a laminated structure in which a base film, an adhesive layer, and a thin metal layer are laminated in the order described above. The aforementioned base film is made of polyethylene terephthalate. The cable according to claim 1 or claim 2, wherein the metal thin layer comprises aluminum or copper.

10. The cable according to claim 1 or claim 2, wherein the metal tape is aluminum foil or copper foil.

11. The cable includes two of the aforementioned wires, The cable according to claim 1 or claim 2, wherein the two electric wires are twisted together.

12. The cable includes two of the aforementioned wires, The cable according to claim 1 or claim 2, wherein the two aforementioned electric wires are wrapped horizontally with resin tape.