Insulated wire

Abstract

The invention provides an insulated wire which can reduce the conduction loss and reduce the environmental load without increasing the outer diameter of the insulated wire. The insulated electric wire (10) is used for being mounted on a conveying device. The insulated electric wire (10) is provided with a conductor (11) formed by twisting a plurality of bare wires (1) and a coating layer (12) for coating the conductor (11). The coating layer (12) is a layer including a separator (13) provided on the outer periphery of the conductor (11), the cross-sectional area of the conductor (11) is at least 1.6 times the cross-sectional area of the coating layer (12), and the thickness of the coating layer (12) is less than 2 mm.

Description

Technical Field

[0001] The present invention relates to insulated wires. Background Art

[0002] As an example of an insulated wire, Patent Document 1 describes an insulated wire including 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.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Laid-Open No. 2022-142862 Summary of the Invention

[0006] Problems to be solved by the invention

[0007] To achieve carbon neutrality, essentially reducing emissions of greenhouse gases such as CO2 to zero, the development of decarbonization technologies is actively underway globally. For example, proposals are underway to design insulated wires used in buildings and factories with larger outer diameters to reduce conduction losses, thereby reducing CO2 emissions and lowering the environmental impact.

[0008] On the other hand, transportation equipment such as automobiles, railway vehicles, aircraft, and ships is wired with numerous insulated wires, including power lines for engines and motors, and control lines for controlling the operation of the transportation equipment. In transportation equipment, there is a need to ensure sufficient space for passengers and cargo, leading to an increasing demand for thinner insulated wires. For example, Patent Document 1 discloses an insulated wire that achieves a thinner diameter and maintains electrical properties by suppressing the thickness of the inner layer of the coating.

[0009] It should be noted that the outer diameter of an insulated wire generally depends on the conductor size. Reducing the conductor size increases the conduction loss, thereby increasing CO₂ emissions. Increasing the conductor size can reduce the conduction loss, but this increases the space required to arrange the insulated wire, making it difficult to secure this space.

[0010] An object of the present invention is to provide an insulated wire that can reduce conduction loss and thus reduce environmental load without increasing the outer diameter of the insulated wire.

[0011] Methods for solving problems

[0012] The insulated wire of the present invention is an insulated wire for use in conveying equipment, comprising a conductor formed by twisting a plurality of bare wires together and a covering layer covering the conductor. The covering layer is a layer including a separator provided on the outer periphery of the conductor. The cross-sectional area of the conductor is 1.6 times or more relative to the cross-sectional area of the covering layer, and the wall thickness of the covering layer is less than 2 mm.

[0013] In one embodiment of the present invention, the coating layer has a multilayer structure of two or more layers.

[0014] In another embodiment of the present invention, the outermost layer of the coating is made of a halogen-free material having a polyolefin as a base polymer, and contains a metal hydroxide as a flame retardant, wherein the amount of the metal hydroxide added is 150 parts by weight or more.

[0015] In another embodiment of the present invention, 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 acrylate copolymer, and an ethylene α-polyolefin.

[0016] In another embodiment of the present invention, the cladding layer has a breakdown electric field of 2400 V / mm or more.

[0017] Effects of the Invention

[0018] According to the present invention, the conduction loss of an insulated wire can be reduced without increasing the outer diameter of the insulated wire, thereby reducing the environmental load. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a cross-sectional view showing the detailed structure of the insulated wire of the present invention.

[0020] Figure 2 This is a cross-sectional view showing an example of a two-layer structure of the coating layer of the insulated wire of the present invention.

[0021] Figure 3 This is a cross-sectional view showing an example of a three-layer structure of the coating layer of the insulated wire of the present invention.

[0022] Figure 4 This is a graph showing the results of the current loss evaluation performed using the insulated wire having a two-layer coating structure according to the present invention.

[0023] Figure 5 It means used for Figure 4 This is a data diagram showing the conductor structure of an insulated wire used for evaluating the conduction loss.

[0024] Description of Reference Numerals

[0025] 1: Bare wire, 2: Sub-stranded wire, 3: Mother stranded wire, 10: Insulated wire, 11: Conductor, 12: Coating, 13: Separator, 14: Outermost layer, 20: Insulated wire, 21: Conductor, 22: Coating, 22a: Inner coating layer, 22b: Outer coating layer, 24: Outermost layer, 30: Insulated wire, 31: Conductor, 32: Coating, 32a: Inner coating layer, 32b: Middle coating layer, 32c: Outer coating layer, 34: Outermost layer, D1: Outer diameter of insulated wire, D2: Outer diameter of conductor, T1: Overall coating thickness, T2: Coating thickness, T3: Wall thickness of separator. DETAILED DESCRIPTION

[0026] An example embodiment of the present invention will be described below with reference to the accompanying drawings. The insulated wire of this embodiment is an insulated wire used in transportation equipment such as automobiles, railway vehicles, aircraft, and ships, and is cross-linked and flame-retardant. It should be noted that in the following description, identical or substantially identical components and elements are generally denoted by the same reference numerals.

[0027] The amount of CO2 emitted throughout the entire product life cycle, from raw materials, manufacturing, use, to disposal and reuse, is calculated. The insulated wire of this embodiment exerts its effect on the amount of CO2 emitted when the wire is used. If current is passed through a conductor, loss is generated in the form of heat due to the influence of the conductor's resistance. When the same current is passed, if the conductor diameter is large, the conductor resistance is low, so the heat generation is small and the loss is suppressed. When using existing wires, simply increasing the size of the conductor will increase the outer diameter of the wire. In this case, the space used to arrange the wire will increase accordingly by the amount of increase in the size of the wire.

[0028] In the present embodiment, conditions for an insulated wire capable of reducing the conduction loss and lowering the environmental load are found without increasing the outer diameter of the insulated wire.

[0029] <Composition of Insulated Wire>

[0030] like Figure 1 As shown, the insulated wire 10 of this embodiment has a conductor 11 and a coating 12 that covers the conductor 11 and is provided around the conductor 11. Specifically, the conductor 11 of the insulated wire 10 is formed by twisting a plurality of bare wires 1. As an example, the bare wire 1 in this embodiment is a copper wire with a diameter of 0.26 mm, and the surface is plated with tin, nickel, silver, etc. Hereinafter, the wire type of the above-mentioned bare wire 1 is also referred to as tinned soft copper wire. Figure 1In the example shown, conductor 11 is composed of 950 bare wires (copper wires) 1 twisted together. More specifically, conductor 11 is a stranded wire (sub-stranded wires 2) obtained by twisting 50 bare wires (copper wires) 1 together, and then a stranded wire (main stranded wire 3) obtained by twisting 19 (19 bundles) of these sub-stranded wires 2 together.

[0031] The insulated wire 10 has a coating 12 covering a conductor 11. The coating 12 includes a separator 13 provided on the outer periphery of the conductor 11 so as to cover the conductor 11. Figure 1 In the illustrated insulated wire 10 , the coating 12 is a single layer, and thus the coating 12 is also the outermost layer 14 .

[0032] Figure 1 D1 shown here represents the outer diameter of the insulated wire 10, and D2 represents the outer diameter of the conductor 11. T3 represents the thickness of the separator 13, T2 represents the thickness of only the coating 12, and T1 represents the entire coating thickness. T1 = T2 + T3.

[0033] Then, Figure 2 The insulated wire 20 of this embodiment shown in FIG. 2 is provided with a conductor 21 and a coating 22 covering the conductor 21 and provided around the conductor 21. The structure of the conductor 21 is similar to that of the insulated wire 20. Figure 1 The structure of the conductor 11 is the same as that of the conductor 11. Although not shown in the figure, a Figure 1 The insulated wire 10 has the same separator 13 .

[0034] In the insulated wire 20, the coating 22 has a two-layer structure. Specifically, the coating 22 is composed of an inner coating layer 22a that coats the conductor 21, and an outer coating layer 22b disposed outside the inner coating layer 22a. In other words, the coating 22 has a two-layer multilayer structure consisting 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.

[0035] Then, Figure 3 The insulated wire 30 of this embodiment shown in FIG. 3 is provided with a conductor 31 and a coating 32 covering the conductor 31 and provided around the conductor 31. The structure of the conductor 31 is similar to that of the insulated wire 30. Figure 1 The structure of the conductor 11 is the same as that of the conductor 11. Although not shown, a Figure 1 The insulated wire 10 has the same separator 13 .

[0036] In the insulated wire 30, the coating 32 has a three-layer structure. Specifically, the coating 32 is composed of an inner coating layer 32a that coats the conductor 31, an outer coating layer 32c disposed outside the inner coating layer 32a, and an intermediate coating layer 32b disposed between the inner coating layer 32a and the outer coating layer 32c. In other words, the coating 32 has a three-layer multilayer 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.

[0037] <About the evaluation of power loss>

[0038] Figure 4 Is to use Figure 2 The data graph of the evaluation results of the current loss evaluation conducted on the insulated wire with a double-layer coating structure shown in FIG. Figure 5 It means used for Figure 4 This is a data diagram showing the conductor structure of an insulated wire used for evaluating the conduction loss.

[0039] Figure 2 The permissible current value of the insulated wire 20 shown is based on IEC 60287, the ambient temperature is set at 45°C, and the DC conductor resistance uses the EN conductor resistance standard value. The outermost layer 24 (cover outer layer 22b) is made of a peroxide-crosslinked material consisting of 70 parts by weight of EV260 (manufactured by Mitsui DuPont Chemical Recycle) as a base polymer, 15 parts by weight of 45LX, and 15 parts by weight of MH7020 (manufactured by Mitsui Chemicals). Furthermore, 180 parts by weight of Magseeds S4 (manufactured by Kojima Chemical) is added as a flame retardant.

[0040] The inner layer (the inner coating layer 22 a ) was made of a mixture of 60 parts by weight of Mitsui Chemicals' A1070S, 30 parts by weight of A4050S, and 10 parts by weight of A35070S, and further mixed with 120 parts by weight of BASF's Translink 37 as a filler, to form a peroxide-crosslinked material.

[0041] In the evaluation of power-on loss, Figure 4 As shown, taking Examples 1, 2, and 3 of the present application as the objects, when comparing each Example with the Comparative Example, if the conduction loss of the Example can be reduced compared with the Comparative Example, with the outer diameter (D1) of the insulated wire being the same, the Example is judged to be qualified.

[0042] It should be noted that when calculating the cross-sectional area of the coating layer, the overall coating layer thickness (T1) = coating layer thickness (T2) + separator wall thickness (T3), and the separator wall thickness (T3) is 0.038 mm (1 / 3 overlap).

[0043] In addition, if Figure 5 As shown, the conductors 21 of the insulated electric wires are all made of tinned annealed copper wire.

[0044] <Evaluation Results>

[0045] exist Figure 4 In the comparison of Examples 1, 2, and 3 with the Comparative Examples, all were judged as acceptable (0). Looking at the "Conductor Cross-sectional Area / Coating Cross-sectional Area" column, the smallest value of the ratio of conductor cross-sectional area to coating cross-sectional area among the Examples was 1.96 for Example 2, while the largest value of the ratio of conductor cross-sectional area to coating cross-sectional area among the Comparative Examples was 1.53 for Comparative Example 1.

[0046] Therefore, it can be seen that if the conductor cross-sectional area is 1.6 times or more relative to the coating cross-sectional area, the current loss can be reduced without increasing the outer diameter of the insulated wire.

[0047] Furthermore, when looking at the column of coating thickness, the largest coating thickness value among the examples is 1.77 mm in Example 2, and the smallest coating thickness value among the comparative examples is 2.29 mm in Comparative Example 3.

[0048] Therefore, it can be seen that by making the thickness of the coating layer less than 2 mm, an increase in the outer diameter of the insulated wire can be suppressed.

[0049] <Preferred Conditions for Insulated Wire>

[0050] In the insulated wire of this embodiment, if the cross-sectional area of the conductor is 1.6 times or more the cross-sectional area of the coating, the conductor resistance can be reduced without increasing the outer diameter of the insulated wire, thereby reducing loss.

[0051] As a result, CO2 emissions can be reduced.

[0052] In addition, if the coating thickness is less than 2 mm, it is easy to form a wire structure in which the cross-sectional area of the conductor is 1.6 times or more relative to the cross-sectional area of the coating, without compressing the wiring space of the insulated wire. Figure 5 , preferably 25SQ or more, which can easily ensure the wiring space of the insulated wire.

[0053] It should be noted that the present invention can be implemented more efficiently by limiting the coating material. For example, by using a coating material with a breakdown electric field of 2400 V / mm or greater, it is easy to increase the cross-sectional area of the conductor to at least 1.6 times the cross-sectional area of the coating layer, thereby reducing the coating layer thickness to less than 2 mm. In this case, the coating layer thickness is preferably less than 2 mm, and more preferably at least 1 mm and less than 2 mm.

[0054] Furthermore, considering environmental impact and safety, the sheathing material of insulated wires used in transportation equipment is preferably flame-retardant, preferably by adding a halogen-free flame retardant. Furthermore, the addition of a metal hydroxide such as aluminum hydroxide or magnesium hydroxide is particularly preferred. For example, an addition amount of 150 parts by weight or more and 250 parts by weight or less can achieve high flame retardancy.

[0055] Other specific applicable halogen-free flame retardants include clay, silica, zinc stannate, zinc borate, calcium borate, dolomite hydroxide (hydrated dolomite), and silicone.

[0056] In addition, the flame retardant may be surface-treated with a silane coupling agent, a titanate coupling agent, or a fatty acid such as stearic acid in consideration of dispersibility and the like.

[0057] In addition, although not particularly limited, in the case of taking into account both the electrical properties and flame retardancy of the coating layer, it is preferred to make a multilayer coating layer, preferably in the outermost layer (e.g., Figure 2 The outermost layer 24 of the insulated wire 20 is a flame retardant layer with a halogen-free flame retardant added, and the inner layer ( Figure 2 The inner layer material of the coating 22a) is made of an inner layer material that emphasizes electrical insulation. In order to further improve the flame retardancy of the outermost layer of the coating, in addition to using a halogen-free flame retardant, a base polymer based on ethylene vinyl acetate copolymer or ethylene acrylate copolymer can also be used.

[0058] The inner layer of the outermost coating layer can be made of a base polymer with low polarity, preferably 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, and ethylene-octene-1 copolymer, which has low hygroscopicity among polyolefins. In this case, the polyolefins can be used alone or in combination of multiple types.

[0059] It should be noted that the coating material applied to the inner layer can be added with a flame retardant or made into a multilayer structure. In addition, the coating layer applied to the outermost layer can be coated on the inner side of the inner layer material as required.

[0060] It should be noted that in Figure 1 In the insulated wire 10 shown, the coating layer 12 becomes the outermost layer 14. Therefore, as the material of the coating layer 12, for example, Figure 2 The outermost layer 24 (the covering outer layer 22 b ) of the insulated wire 20 is made of the same material.

[0061] In addition, Figure 3In the insulated wire 30 having a multilayer coating structure, the coating outer layer 32c is the outermost layer 34. Therefore, as the material of the coating outer layer 32c, for example, Figure 2 The outermost layer 24 (covering outer layer 22b) of the insulated wire 20 is made of the same material. Figure 3 The material of the coating intermediate layer 32b of the insulated wire 30 is preferably Figure 2 The same material as the inner layer 22a of the insulated wire 20. Figure 3 The material of the inner coating layer 32a of the insulated wire 30 is preferably Figure 2 The outer covering layer 22b of the insulated wire 20 is made of the same material.

[0062] According to the insulated wire of this embodiment, the conduction loss can be reduced without increasing the outer diameter of the insulated wire. As a result, CO2 emissions can be reduced, thereby reducing the environmental impact.

[0063] Furthermore, by forming the covering layer of the insulated wire from a halogen-free material, the environmental load can be further reduced.

[0064] The present invention is not limited to the above-described embodiment, and various modifications are possible without departing from the spirit and scope of the present invention. For example, the outer diameter (D1) of the insulated wire described in the above-described embodiment is a maximum of 24.2 mm, but the outer diameter (D1) of the insulated wire may be greater than 24.2 mm.

Claims

1. An insulated wire for use on a conveyor. The insulated wire includes a conductor formed by twisting a plurality of bare wires and a coating covering the conductor. The coating layer is a layer including a separator provided on the outer periphery of the conductor. The cross-sectional area of the conductor is 1.6 times or more of the cross-sectional area of the coating layer, and the wall thickness of the coating layer is less than 2 mm.

2. The insulated wire according to claim 1, wherein The coating layer is a multi-layer structure with more than two layers.

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

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

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

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