Insulated electric wire

Abstract

To allow reduction of conduction loss and lowering of environmental burden in an insulated electric wire without enlargement of the outer diameter of the insulated electric wire.SOLUTION: An insulated electric wire 10 for installation in a transport machine comprises: a conductor 11 constituted by stranding together a plurality of strands 1; and a covering layer 12 coating the conductor 11, the covering layer 12 being a layer including a separator 13 disposed around an outer periphery of the conductor 11, where a cross-sectional area of the conductor 11 is 1.6 times or greater a cross-sectional area of the covering layer 12, and a wall thickness of the covering layer 12 is less than 2 mm.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an insulated wire. [Background technology]

[0002] As an example of an insulated wire, Patent Document 1 describes an insulated wire having a conductor, an inner layer covering the conductor, an outer layer covering the inner layer, and a sheath covering the outer layer, wherein the outer layer and the sheath are flame retardant. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2022-142862 Summary of the Invention [Problem to be solved by the invention]

[0004] CO 2 The development of decarbonization technologies is gaining momentum around the world in order to achieve carbon neutrality, which means that greenhouse gas emissions such as CO2 can be reduced by designing the outer diameter of the insulated wires used in buildings and factories to be large. 2 It has been proposed to reduce the environmental impact by reducing

[0005] Meanwhile, transportation equipment such as automobiles, railcars, aircraft, and ships are wired with a large number of insulated electric wires, such as power lines for engines and motors, and control lines for controlling the operation of the transportation equipment. Transportation equipment is required to ensure space for carrying passengers and luggage, and there is a growing need for thinner insulated electric wires. For example, Patent Document 1, cited above, discloses an insulated electric wire that maintains electrical properties by reducing the thickness of the inner layer of the coating to reduce the diameter.

[0006] The outer diameter of an insulated wire generally depends on the conductor size, and reducing the conductor size increases current loss. 2 In addition, although it is possible to reduce current loss by increasing the conductor size, it requires more space to place the insulated wire, making it difficult to secure that space.

[0007] An object of the present invention is to provide an insulated wire that can reduce current loss and reduce environmental impact without increasing the outer diameter of the insulated wire. [Means for solving the problem]

[0008] The insulated wire of the present invention is an insulated wire to be installed in transportation equipment, and includes a conductor formed by twisting together a plurality of wires, and a coating layer that coats the conductor, wherein the coating layer is a layer that includes a separator provided on the outer periphery of the conductor, the cross-sectional area of ​​the conductor being 1.6 times or more the cross-sectional area of ​​the coating layer, and the thickness of the coating layer being less than 2 mm.

[0009] In one embodiment of the present invention, the coating layer has a multi-layer structure of two or more layers.

[0010] In another aspect of the present invention, the outermost layer of the coating layer is made of a halogen-free material with a polyolefin base polymer and contains a metal hydroxide as a flame retardant, and the amount of the metal hydroxide added is 150 parts by weight or more.

[0011] In yet another aspect of the present invention, the coating layer contains a polyolefin, and the polyolefin contained in the coating layer includes any one of ethylene vinyl acetate copolymer, ethylene acrylic acid ester copolymer, and ethylene alpha polyolefin.

[0012] In yet another aspect of the present invention, the breakdown electric field of the coating layer is 2400 V / mm or more. [Effects of the Invention]

[0013] According to the present invention, in an insulated wire, it is possible to reduce current loss and reduce environmental load without increasing the outer diameter of the insulated wire. [Brief explanation of the drawings]

[0014] [Figure 1] FIG. 2 is a cross-sectional view showing a detailed structure of the insulated wire of the present invention. [Figure 2] 1 is a cross-sectional view showing an example of a two-layer coating structure of an insulated wire of the present invention. [Figure 3] 1 is a cross-sectional view showing an example of a three-layer coating structure of an insulated wire according to the present invention. [Figure 4] FIG. 2 is a data chart showing the results of a current loss evaluation carried out using an insulated wire with a two-layer coating structure of the present invention. [Figure 5] FIG. 5 is a data diagram showing the configuration of the conductor of the insulated wire used in the current loss evaluation of FIG. 4. DETAILED DESCRIPTION OF THE INVENTION

[0015] An example of an embodiment of the present invention will be described below with reference to the drawings. The insulated wire of this embodiment is an insulated wire that is installed in transportation equipment such as automobiles, railroad cars, aircraft, and ships, and that has cross-linked flame retardancy. In the following description, the same reference numerals will be used in principle for identical or substantially identical configurations, elements, etc.

[0016] CO emissions throughout the product lifecycle, from raw materials, manufacturing, use, disposal, and recycling 2 The insulated wire of this embodiment calculates the CO emissions during use of the wire. 2 This has an effect on the amount of carbon dioxide emitted. When a current flows through a conductor, heat is lost due to the conductor resistance. If the same current flows, a larger conductor diameter results in lower conductor resistance, which reduces heat generation and suppresses loss. When using existing electric wires, simply increasing the size of the conductor increases the outer diameter of the wire. In this case, the space required to place the wire increases by the amount of increase in size.

[0017] In this embodiment, conditions for an insulated wire that can reduce the current loss and the environmental load without increasing the outer diameter of the insulated wire are found. <Insulated wire structure> As shown in FIG. 1 , an insulated wire 10 according to this embodiment includes a conductor 11 and a coating layer 12 that covers and surrounds the conductor 11. Specifically, the conductor 11 of the insulated wire 10 is formed by twisting together a plurality of wires 1. The wires 1 in this embodiment are, for example, copper wires with a diameter of 0.26 mm, the surfaces of which are plated with tin, nickel, silver, or the like. Hereinafter, the wire type of the wire 1 will also be referred to as a tin-plated annealed copper wire. In the exemplary structure shown in FIG. 1 , the conductor 11 is formed by a composite twist of 950 wires (copper wires) 1. More specifically, the conductor 11 is a twisted wire (parent twisted wire 3) formed by twisting together 19 strands (19 bundles) of wires (child twisted wires 2) each of which is formed by twisting together 50 wires (copper wires) 1.

[0018] The insulated wire 10 has a coating layer 12 that coats the conductor 11, and the coating layer 12 includes a separator 13 that is provided on the outer periphery of the conductor 11 so as to coat the conductor 11. In the insulated wire 10 shown in FIG. 1 , the coating layer 12 is a single layer, and therefore the coating layer 12 also serves as the outermost layer 14.

[0019] 1, D1 is the outer diameter of the insulated wire 10, and D2 is the outer diameter of the conductor 11. Furthermore, T3 is the thickness of the separator 13, T2 is the thickness of only the coating layer 12, and T1 is the total thickness of the coating layers, where T1 = T2 + T3.

[0020] Next, an insulated wire 20 of this embodiment shown in Fig. 2 will be described. The insulated wire 20 has a conductor 21 and a coating layer 22 that coats and surrounds the conductor 21. The structure of the conductor 21 is similar to that of the conductor 11 in Fig. 1. Although not shown, a separator 13 similar to that of the insulated wire 10 in Fig. 1 is provided around the conductor 21.

[0021] In the insulated wire 20, the coating layer 22 has a two-layer structure. Specifically, the coating layer 22 is composed of an inner coating layer 22a that covers the conductor 21 and an outer coating layer 22b that is provided on the outside of the inner coating layer 22a. In other words, the coating layer 22 has a two-layer structure made up of the inner coating layer 22a and the outer coating layer 22b. Therefore, in the insulated wire 20, the outer coating layer 22b is the outermost layer 24.

[0022] Next, an insulated wire 30 of this embodiment shown in Fig. 3 will be described. The insulated wire 30 has a conductor 31 and a coating layer 32 that covers and surrounds the conductor 31. The structure of the conductor 31 is similar to that of the conductor 11 in Fig. 1. Although not shown, a separator 13 similar to that of the insulated wire 10 in Fig. 1 is provided around the conductor 31.

[0023] In the insulated wire 30, the coating layer 32 has a three-layer structure. Specifically, the coating layer 32 is composed of an inner coating layer 32a that covers the conductor 31, an outer coating layer 32c that is provided on the outside of the inner coating layer 32a, and an intermediate coating layer 32b that is provided between the inner coating layer 32a and the outer coating layer 32c. In other words, the coating layer 32 has a three-layer structure consisting of the inner coating layer 32a, the intermediate coating layer 32b, and the outer coating layer 32c. Therefore, in the insulated wire 30, the outer coating layer 32c is the outermost layer 34. <About current loss evaluation> FIG. 4 is a data diagram showing the results of a current loss evaluation performed using an insulated wire having the double-coating layer structure shown in FIG. 2, and FIG. 5 is a data diagram showing the configuration of the conductor of the insulated wire used in the current loss evaluation of FIG. 4.

[0024] 2 was determined based on IEC 60287, assuming an ambient temperature of 45°C, and the DC conductor resistance was determined using the EN conductor resistance standard value. The coating material for the outermost layer 24 (coating outer layer 22b) was a peroxide-crosslinked material obtained by mixing 70 parts by weight of EV260 manufactured by Mitsui DuPont Chemical Recycle, 15 parts by weight of 45LX, and 15 parts by weight of MH7020 manufactured by Mitsui Chemicals as a base polymer, and further mixing 180 parts by weight of Magseeds S4 manufactured by Konoshima Chemical Co., Ltd. as a flame retardant.

[0025] Furthermore, for the inner layer (coating inner layer 22a), 60 parts by weight of A1070S manufactured by Mitsui Chemicals, 30 parts by weight of A4050S, and 10 parts by weight of A35070S were mixed, and further 120 parts by weight of Translink 37 manufactured by BASF was mixed as a filler, to form a peroxide-crosslinked material.

[0026] In the evaluation of current loss, as shown in FIG. 4, Examples 1, 2, and 3 of the present invention were used as the targets, and in a comparison between each Example and the Comparative Example, when the outer diameter (D1) of the insulated wire was the same, if the Example had a lower current loss than the Comparative Example, the Example was judged to be acceptable.

[0027] In calculating the cross-sectional area of ​​the coating layer, the total thickness of the coating layer (T1) = the coating layer thickness (T2) + the separator thickness (T3), and the separator thickness (T3) is 0.038 mm (1 / 3 wrap).

[0028] As shown in FIG. 5, the conductors 21 of the insulated wires were all made of tin-plated annealed copper wires. <Evaluation results> 4, Examples 1, 2, and 3 were all judged to be pass (◯) in comparison with each of the comparative examples. Looking at the conductor cross-sectional area / coating layer cross-sectional area item, the smallest conductor cross-sectional area / coating layer cross-sectional area value among the examples was 1.96 for Example 2, and the largest conductor cross-sectional area / coating layer cross-sectional area value among the comparative examples was 1.53 for Comparative Example 1.

[0029] Therefore, it was found that if the cross-sectional area of ​​the conductor is 1.6 times or more the cross-sectional area of ​​the coating layer, the current loss can be reduced without increasing the outer diameter of the insulated wire.

[0030] Furthermore, looking at the coating layer thickness item, the largest coating layer thickness value among the examples is Example 2, which is 1.77 mm, and the smallest coating layer thickness value among the comparative examples is Comparative Example 3, which is 2.29 mm.

[0031] Therefore, it was found that by making the thickness of the coating layer less than 2 mm, it is possible to suppress an increase in the outer diameter of the insulated wire. <Optimal conditions for insulated wire> In the insulated wire of the present embodiment, if the wire structure has a conductor cross-sectional area that is 1.6 times or more the cross-sectional area of ​​the coating layer, it is possible to reduce the conductor resistance and loss without increasing the outer diameter of the insulated wire.

[0032] As a result, CO 2 emissions can be reduced.

[0033] Furthermore, if the coating thickness is less than 2 mm, it is easy to create a wire structure in which the cross-sectional area of ​​the conductor is 1.6 times or more the cross-sectional area of ​​the coating layer, and the wiring space for the insulated wire is not restricted. In this case, as shown in Figure 5, the outer diameter of the insulated wire is preferably 25 SQ or more, which is effective in ensuring the wiring space for the insulated wire.

[0034] The present invention can be implemented more effectively by limiting the coating material. For example, by using a coating material with a breakdown field of 2400 V / mm or more, it becomes easy to make the cross-sectional area of ​​the conductor 1.6 times or more the cross-sectional area of ​​the coating layer and to make the coating layer thickness less than 2 mm. In this case, the coating layer thickness is preferably less than 2 mm, and more preferably 1 mm or more but less than 2 mm.

[0035] Furthermore, when environmental impact is taken into consideration, it is preferable that the coating material for insulated electric wires to be installed in transportation equipment be flame-retardant from the viewpoint of safety, and in particular, it is preferable to add a halogen-free flame retardant.Furthermore, it is preferable to add a metal hydroxide such as aluminum hydroxide or magnesium hydroxide, and high flame retardancy can be obtained when the amount added is, for example, 150 parts by weight or more and 250 parts by weight or less.

[0036] Other applicable specific non-halogen flame retardants include clay, silica, zinc stannate, zinc borate, calcium borate, dolomide hydroxide, and silicone.

[0037] In consideration of dispersibility, the flame retardant may be surface-treated with a silane coupling agent, a titanate coupling agent, or a fatty acid such as stearic acid.

[0038] Furthermore, although not particularly limited, when the electrical properties and flame retardancy of the coating layer are to be compatible, it is preferable to use a coating layer with a multilayer structure, and it is preferable to use a flame-retardant layer containing a non-halogen flame retardant as the outermost layer of the coating layer of the multilayer structure (for example, outermost layer 24 of insulated electric wire 20 in FIG. 2), and to use an inner layer material that emphasizes electrical insulation as the layer further inside (inner coating layer 22a in FIG. 2).In order to further improve the flame retardancy of the outermost layer of the coating layer, it is preferable to use a base polymer based on ethylene vinyl acetate copolymer or ethylene acrylate copolymer, in addition to using a non-halogen flame retardant.

[0039] For the inner layer of the outermost coating layer, a base polymer with low polarity is preferably used, and among polyolefins, it is preferable to use an ethylene-α-polyolefin copolymer such as high-density polyethylene, medium-density polyethylene, low-density polyethylene, linear low-density polyethylene, ethylene-butene-1 copolymer, ethylene-hexene-1 copolymer, or ethylene-octene-1 copolymer, which has low moisture absorption. In this case, the polyolefin may be used alone or in combination with multiple polyolefins.

[0040] The coating material applied to the inner layer may contain a flame retardant and may have a multi-layer structure. If necessary, the coating layer applied to the outermost layer may be further coated on the inner side of the inner layer material.

[0041] In the insulated wire 10 shown in FIG. 1, the coating layer 12 is the outermost layer 14, and therefore, it is preferable to use, for example, the same material as that of the outermost layer 24 (outer coating layer 22b) of the insulated wire 20 shown in FIG. 2 as the material for the coating layer 12.

[0042] In the insulated wire 30 having a multilayer coating structure shown in Fig. 3, the outer coating layer 32c is the outermost layer 34, and therefore, the material for the outer coating layer 32c is preferably the same as the material for the outermost layer 24 (outer coating layer 22b) of the insulated wire 20 in Fig. 2. Furthermore, the material for the intermediate coating layer 32b of the insulated wire 30 in Fig. 3 is preferably the same as the material for the inner coating layer 22a of the insulated wire 20 in Fig. 2. Furthermore, the material for the inner coating layer 32a of the insulated wire 30 in Fig. 3 is preferably the same as the material for the outer coating layer 22b of the insulated wire 20 in Fig. 2.

[0043] According to the insulated wire of this embodiment, the current loss can be reduced without increasing the outer diameter of the insulated wire. 2 This will reduce emissions and reduce the environmental impact.

[0044] Furthermore, since the coating layer of the insulated wire is made of a halogen-free material, the environmental impact can be further reduced.

[0045] The present invention is not limited to the above-described embodiment, and various modifications are possible without departing from the spirit of the present invention. For example, although the insulated wire outer diameter (D1) described in the above-described embodiment is 24.2 mm at maximum, the insulated wire outer diameter (D1) may be 24.2 mm or more. [Explanation of symbols]

[0046] 1 wire 2-ply stranded wire 3 Parent strands 10 Insulated wire 11 Conductor 12 Covering layer 13 Separator 14 Outermost layer 20 Insulated wire 21 Conductor 22 Covering layer 22a Inner coating layer 22b outer coating layer 24 Outermost layer 30 Insulated wire 31 Conductor 32 Covering layer 32a Inner coating layer 32b Intermediate coating layer 32c outer coating layer 34 Outermost layer D1 Insulated wire outer diameter D2 Conductor outer diameter T1 Total coating thickness T2 Coating thickness T3 Separator wall thickness

Claims

1. An insulated wire to be installed in a transportation device, a conductor formed by twisting together a plurality of wires; a coating layer that coats the conductor, the covering layer is a layer including a separator provided on the outer periphery of the conductor, An insulated wire, wherein the cross-sectional area of ​​the conductor is 1.6 times or more the cross-sectional area of ​​the coating layer, and the thickness of the coating layer is less than 2 mm.

2. The insulated wire according to claim 1, The insulated wire, wherein the covering layer has a multi-layer structure of two or more layers.

3. The insulated wire according to claim 2, the outermost layer of the coating layer is made of a halogen-free material having a polyolefin base polymer and containing a metal hydroxide as a flame retardant; The insulated wire, wherein the amount of the metal hydroxide added is 150 parts by weight or more.

4. The insulated wire according to claim 1, the coating layer contains a polyolefin, and the polyolefin contained in the coating layer includes any one of an ethylene-vinyl acetate copolymer, an ethylene-acrylic acid ester copolymer, and an ethylene-α-polyolefin.

5. The insulated wire according to claim 1, 2, 3 or 4, The insulated wire, wherein the breakdown field of the coating layer is 2400 V / mm or more.

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