Multicore cable

Abstract

To provide a multicore cable from which a sheath can be removed easily.SOLUTION: A multicore cable includes: a core made by twisting together a plurality of electric wires; a release layer that covers the core; and a sheath that covers the release layer. Tensile strength of the release layer is 10-38 MPa, and the release layer is firmly fixed to the sheath.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to a multi-core cable.

Background Art

[0002] Patent Document 1 discloses a multi-core cable having a core formed by twisting a plurality of core insulated wires and a sheath layer covering the outer periphery of the core.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In order to connect the electric wires of a multi-core cable to equipment or the like, at the end of the multi-core cable, an outer sheath that collectively covers the electric wires has conventionally been pulled along the longitudinal direction of the multi-core cable and removed. From the viewpoint of improving workability, it has been required that the outer sheath of the multi-core cable can be easily removed.

[0005] Therefore, an object of the present disclosure is to provide a multi-core cable that can easily remove the outer sheath.

Means for Solving the Problems

[0006] The multi-core cable of the present disclosure has a core formed by twisting a plurality of electric wires, a release layer covering the core, and an outer sheath covering the release layer, the tensile strength of the release layer is 10 MPa or more and 38 MPa or less, and the release layer is fixed to the outer sheath.

Effects of the Invention

[0007] ​​​​​ The present disclosure can provide a multi-core cable whose outer covering can be easily removed.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Modes for Carrying Out the Invention

[0009] The modes for carrying out the invention will be described below.

[0010] [Description of Embodiments of the Present Disclosure] First, the embodiments of the present disclosure will be listed and described. In the following description, the same or corresponding elements are denoted by the same reference numerals, and the same description thereof will not be repeated.

[0011] (1) A multi-core cable according to one aspect of the present disclosure includes a core formed by twisting a plurality of electric wires, a release layer covering the core, and an outer covering covering the release layer, and the release layer has a tensile strength of 10 MPa or more and 38 MPa or less, and the release layer is fixed to the outer covering.

[0012] By setting the tensile strength of the release layer to 38 MPa or less, when the outer covering to be removed is pulled along the longitudinal direction of the multi-core cable, the release layer can be easily cut, and the outer covering can be easily removed.

[0013] By setting the tensile strength of the release layer to 10 MPa or more, it is possible to prevent the material such as the tape of the release layer from being cut during the production of the release layer, and the productivity of the multi-core cable can be improved.

[0014] When the release layer adheres to the outer cover, when removing the outer cover, the release layer and the outer cover can be peeled off from the core as a whole, and the outer cover can be easily removed.

[0015] (2) In the above (1), the difference between the melting temperature of the material contained in the surface of the release layer in contact with the outer cover and the melting temperature of the material contained in the surface of the outer cover in contact with the release layer may be 60°C or less.

[0016] By setting the difference between the melting temperature of the material contained in the surface of the release layer in contact with the outer cover and the melting temperature of the material contained in the surface of the outer cover in contact with the release layer to 60°C or less, when extruding and molding the outer cover on the release layer, the vicinity of the surface of the release layer in contact with the outer cover can be melted, and the release layer can be easily adhered to the outer cover.

[0017] (3) In the above (1) or (2), the release layer may include a plurality of materials. The difference between the melting temperature of at least a part of the material contained in the surface of the release layer in contact with the outer cover and the melting temperature of the material contained in the surface of the outer cover in contact with the release layer may be 60°C or less.

[0018] By setting the difference between the melting temperature of at least a part of the material contained in the surface of the release layer in contact with the outer cover and the melting temperature of the material contained in the surface of the outer cover in contact with the release layer to 60°C or less, when extruding and molding the outer cover on the release layer, at least a part of the surface of the release layer in contact with the outer cover can be melted. Therefore, when extruding and molding the outer cover, at least a part of the release layer can be fixed to the outer cover.

[0019] (4) In any of the above (1) to (3), the release layer may include a non-woven fabric.

[0020] Since the release layer includes a non-woven fabric, when removing the outer cover, the release layer can be easily cut, and the outer cover can be easily removed. Also, since the release layer includes a non-woven fabric, it is possible to prevent fine scraps from being generated when the release layer is torn during the removal of the outer cover.

[0021] (5) In the above (4), the non-woven fabric may contain fibers having a core-sheath structure including a core and a sheath disposed outside the core.

[0022] Since the fibers contained in the non-woven fabric have a core-sheath structure, by selecting the materials for the core and the sheath, it is possible to obtain fibers that can satisfy the properties required for the fibers and the non-woven fabric. For example, by using different materials for the core and the sheath, the properties of the fibers and the non-woven fabric containing the fibers can be easily controlled.

[0023] [Details of Embodiments of the Present Disclosure] A specific example of a multi-core cable according to an embodiment of the present disclosure (hereinafter referred to as "the present embodiment") will be described below with reference to the drawings. Note that the present invention is not limited to these examples, and is defined by the claims, and is intended to include all modifications within the meaning and scope equivalent to the claims.

[0024] In this specification, when members such as the first electric wire and the second electric wire are described by adding first, second, etc. to the names of the members, the first, second, etc. are merely described for the purpose of identifying each member and preventing confusion during the description, and do not represent the arrangement, priority, etc. Therefore, when there is no particular risk of confusion or when the description is made collectively, it can be simply expressed as an electric wire. [Multi-core Cable] FIG. 1 shows a schematic cross-sectional view perpendicular to the longitudinal direction of the multi-core cable of the present embodiment. In FIG. 1, the longitudinal direction of the multi-core cable is along the Z-axis, that is, an axis perpendicular to the paper surface. FIG. 1 shows a cross-section in the XY plane perpendicular to the Z-axis. FIG. 1 is a diagram schematically shown for explanation, and the number of electric wires, the configuration, etc. of the multi-core cable of the present embodiment are not limited to such forms.

[0025] As shown in FIG. 1, the multi-core cable 10 of the present embodiment has a core 110 formed by twisting a plurality of electric wires 11, a release layer 12 covering the core 110, and an outer jacket 13 covering the release layer 12.

[0026] The members included in the multi-core cable of this embodiment will be described. (1) Core The core 110 has a structure in which a plurality of electric wires 11 are twisted together. (1-1) Regarding the electric wire The electric wire 11 included in the core 110 can have a conductor 11A and an insulator 11B that coats the conductor 11A. (1-1-1) Conductor The conductor 11A can be a stranded wire in which a plurality of conductor strands 11C are twisted together.

[0027] For example, as shown in FIG. 1, the first conductor 111A may be a stranded wire of a plurality of first conductor strands 111C. Also, the second conductor 112A may be a stranded wire of a plurality of second conductor strands 112C. In FIG. 1, one first conductor strand 111C is shown as one circle, but one circle may be a stranded wire of a plurality of first conductor strands 111C or one first conductor strand 111C. In FIG. 1, a plurality of second conductor strands 112C are collectively shown as one circle for the second conductor strand 112C.

[0028] The material of the conductor 11A is not particularly limited, and for example, a copper alloy or copper can be used. The conductor may or may not be plated. (1-1-2) Insulator As shown in FIG. 1, the insulator 11B can coat the outer surface of the conductor 11A.

[0029] (Resin material) The insulator 11B can contain a resin material. The resin material is not particularly limited. For example, one or more resins selected from fluororesins such as polytetrafluoroethylene (PTFE), tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), ethylene-tetrafluoroethylene copolymer (ETFE), polyolefin resins such as polyethylene and polypropylene, and copolymers of olefins and comonomers (ethylene-vinyl acetate copolymer (EVA), ethylene-ethyl acrylate copolymer (EEA), ethylene-methyl acrylate copolymer (EMA), etc.) can be used. The resin of the insulator may or may not be crosslinked.

[0030] (Additive) In addition to the above resin material, the insulator 11B can also contain one or more additives selected from flame retardants, antioxidants, deterioration inhibitors, acid acceptors, colorants, crosslinking agents, crosslinking aids, processing aids, fillers, lubricants, etc. (1-2) Regarding the configuration of the wires included in the core The configuration of the plurality of wires 11 included in the core 110 of the multi-core cable 10 of the present embodiment is not particularly limited. The plurality of wires 11 included in the core 110 can have any number and combination of wires 11 according to the use of the multi-core cable 10 and the like.

[0031] For example, like the core 110 of the multi-core cable 10 shown in FIG. 1, the core 110 can include two first wires 111 and two second wires 112 as the plurality of wires 11.

[0032] The first wire 111 and the second wire 112 can have the configuration of the wire 11. That is, as shown in FIG. 1, the first wire 111 has a first conductor 111A which is a conductor 11A and a first insulator 111B which is an insulator 11B. The second wire 112 has a second conductor 112A which is a conductor 11A and a second insulator 112B which is an insulator 11B. Each member is as described above.

[0033] The two second electric wires 112 can also be a pair-twisted electric wire 1120 that is pre-twisted together. In the case of the multi-core cable 10 in FIG. 1, the pair-twisted electric wire 1120 and the two first electric wires 111 are twisted together to form the core 110.

[0034] By making the second electric wire 112 a pair-twisted electric wire, the second electric wire 112 can suppress the deterioration and attenuation of the signal to be transmitted. Also, by making the second electric wire 112 a pair-twisted electric wire, the two can be handled together when wiring or the like, and the workability during wiring can be improved.

[0035] The pair-twisted electric wire 1120 can further have a coating layer 14 that covers the two twisted second electric wires 112. The coating layer 14 may be composed of one layer, or may be composed of two layers such as a first coating layer 141 and a second coating layer 142 or three or more layers.

[0036] The material of the coating layer 14 is not particularly limited. For example, the same material as the insulator 11B can be used, or different materials can be used.

[0037] As the material of the first coating layer 141, for example, one or more selected from thermoplastic polyurethane elastomer, EVA, EEA, etc. can be used. As the material of the second coating layer 142, for example, thermoplastic polyurethane elastomer or the like can be used.

[0038] The coating layer 14 can also have a configuration in which a tape is wound, or can be an extruded resin tube.

[0039] The pair-twisted electric wire 1120 may have a configuration in which the coating layer 14 is not provided and the two second electric wires 112 are exposed. (2) Release layer The release layer 12 can cover the core 110 and can be arranged so as to be in direct contact with the outer surface 110A of the core 110.

[0040] The release layer 12 can have a configuration in which, for example, a tape-shaped nonwoven fabric or the like is wound around the core 110. The tape can be wound around the core 110 in a spiral, for example. At this time, the angle of the spirally wound tape may be, for example, 25 degrees or more and 40 degrees or less with respect to the central axis along the longitudinal direction of the multi-core cable 10 (0 degrees). The overlapping width of the tape may be, for example, 1 / 3 or more and 1 / 2 or less of the tape width.

[0041] The removal of the outer sheath 13 in the multi-core cable 10 can be carried out, for example, by the following first step and second step. In the first step, as shown in FIG. 3, at the end 10A of the multi-core cable 10, a cut 31 that reaches the release layer 12 can be made in the outer sheath 13. Next, in the second step, the outer sheath 13 can be pulled and removed along the multi-core cable 10 in the longitudinal direction along the block arrow 32.

[0042] In the first step, by selecting the length L13 corresponding to the distance from the end 10A of the multi-core cable 10 to the position where the cut 31 is made, the length L13 of the outer sheath 13 to be removed, that is, the length of the exposed core 110, can be selected.

[0043] Conventionally, for example, when the length L13 of the outer sheath 13 to be removed is 400 mm or more, the cut 31 is made in the first step so that the length L13 of the outer sheath 13 removed at one time is about 100 mm, and the first step and the second step are repeated to remove the outer sheath 13 of the desired length. However, from the viewpoint of improving productivity, even when the length L13 of the outer sheath 13 to be removed is 400 mm or more, there is a demand for a multi-core cable 10 that can be removed all at once by performing the first step and the second step once. Therefore, in this specification, a multi-core cable that can easily remove the outer sheath means a multi-core cable that can remove the outer sheath 13 with a length L13 of 400 mm along the longitudinal direction of the multi-core cable 10 all at once.

[0044] Therefore, the inventor of the present invention has studied a multi-core cable 10 in which, even when the length L13 of the jacket 13 to be removed is 400 mm or more, the jacket 13 can be easily removed along the longitudinal direction. In the course of the study, the inventor of the present invention has studied a configuration in which a release layer 12 is disposed between the core 110 and the jacket 13.

[0045] However, when a release layer 12 is disposed between the core 110 and the jacket 13 and an attempt is made to remove the jacket 13 having a length L13 of 400 mm or more at the end 10A along the longitudinal direction of the multi-core cable 10 at once, the release layer 12 may overlap and jam between the jacket 13 and the core 110. Then, when the release layer 12 jams between the jacket 13 and the core 110, more force is required to pull the jacket 13, and the removal of the jacket 13 may become difficult instead.

[0046] The inventor of the present invention has studied the cause of the release layer 12 jamming between the jacket 13 and the core 110 when removing the jacket 13. As a result, it has become clear that when the release layer 12 jams between the jacket 13 and the core 110, the release layer 12 is not fixed (adhered) to the jacket 13.

[0047] Therefore, in the multi-core cable 10 of the present embodiment, a configuration can be achieved in which the release layer 12 is fixed to the jacket 13. By fixing the release layer 12 to the jacket 13, when removing the jacket 13, the release layer 12 and the jacket 13 can be peeled off from the core 110 integrally, and the jacket 13 can be easily removed. The fact that the release layer 12 is fixed to the jacket 13 can be confirmed in any cross-section perpendicular to the longitudinal direction of the multi-core cable 10, and when at least a part is adhered at the interface between the release layer 12 and the jacket 13, it can be determined that they are fixed.

[0048] The melting temperature T12 of the material contained in the surface 12A of the release layer 12 in contact with the jacket 13 and the melting temperature T13 of the material contained in the surface 131A of the jacket 13 in contact with the release layer 12 may be selected so as to fix the release layer 12 to the jacket 13.

[0049] The melting temperature T12 and the melting temperature T13 may be of the same degree, or T12 < T13. The melting temperature T12 and the melting temperature T13 may be such that T12 > T13. If the difference between the melting temperature T12 and the melting temperature T13 is about 60°C or less, the release layer 12 can be configured to adhere to the outer cover 13.

[0050] Since the surface 12A of the release layer 12 in contact with the outer cover 13 and the surface 131A of the outer cover 13 in contact with the release layer 12 have a certain thickness, they can also be respectively referred to as the layer of the release layer 12 in contact with the outer cover 13 and the layer of the outer cover 13 in contact with the release layer 12.

[0051] In the multi-core cable 10 shown in FIG. 1, for example, the melting temperature of the release layer 12 is set as the melting temperature T12, and the melting temperature of the first outer cover 131 is set as the melting temperature T13, so that the melting temperatures can be compared.

[0052] The melting temperature means the peak temperature of the first endothermic peak when the material to be evaluated is heated from room temperature (25°C) at a heating rate of 10°C / min by DSC (Differential Scanning Calorimetry).

[0053] The difference between the melting temperature T12 of the material contained in the surface 12A of the release layer 12 in contact with the outer cover 13 and the melting temperature T13 of the material contained in the surface 131A of the outer cover 13 in contact with the release layer 12 may be 60°C or less.

[0054] By setting the difference between the melting temperature T12 and the melting temperature T13 to 60°C or less, when the outer cover 13 is extrusion-molded on the release layer 12, the vicinity of the surface 12A of the release layer 12 in contact with the outer cover 13 can be melted, and the release layer 12 can be easily fixed to the outer cover 13.

[0055] The difference between the melting temperature T12 and the melting temperature T13 may be 50°C or less.

[0056] Therefore, the difference between the melting temperature T12 and the melting temperature T13 may be 0°C or more and 60°C or less, or may be 0°C or more and 50°C or less.

[0057] When the release layer 12 contains a plurality of materials, the difference between the melting temperature T121 of at least a part of the material contained in the surface of the release layer 12 in contact with the jacket 13 and the melting temperature T13 of the material contained in the surface of the jacket 13 in contact with the release layer 12 may be 60 °C or less.

[0058] By setting the difference between the melting temperature T121 and the melting temperature T13 to 60 °C or less, when the jacket 13 is extrusion-molded on the release layer 12, at least a part of the surface 12A of the release layer 12 in contact with the jacket 13 can be melted. Therefore, when the jacket 13 is extrusion-molded on the release layer 12, at least a part of the release layer 12 can be fixed to the jacket 13.

[0059] The difference between the melting temperature T121 and the melting temperature T13 may be 50 °C or less.

[0060] Therefore, the difference between the melting temperature T121 and the melting temperature T13 may be 0 °C or more and 60 °C or less, and may be 0 °C or more and 50 °C or less.

[0061] The release layer 12 can have a tensile strength of 38 MPa or less. By setting the tensile strength of the release layer 12 to 38 MPa or less, when the jacket 13 to be removed is pulled along the longitudinal direction of the multi-core cable 10, the release layer 12 can be easily cut and the jacket 13 can be easily removed.

[0062] The release layer 12 may have a tensile strength of 15 MPa or less. By setting the tensile strength of the release layer 12 to 15 MPa or less, the release layer 12 can be cut more easily and the jacket 13 can be easily removed.

[0063] The release layer 12 may have a tensile strength of 10 MPa or more. By setting the tensile strength of the release layer 12 to 10 MPa or more, it is possible to prevent the material such as the tape of the release layer 12 from being cut during the production of the release layer 12, and the productivity of the multi-core cable can be increased.

[0064] Therefore, the tensile strength of the release layer 12 can be, for example, 10 MPa or more and 38 MPa or less.

[0065] The material of the release layer 12 is not particularly limited, and may include one or more resins selected from, for example, polyester resins such as polyethylene terephthalate (PET), polyolefin resins such as polyethylene and polypropylene, and the like.

[0066] The release layer 12 may be a non-woven fabric containing resin fibers or the like, or a tape having a resin base material or the like.

[0067] As described above, the release layer 12 can include, for example, a non-woven fabric. By including a non-woven fabric in the release layer 12, when removing the outer cover 13, the release layer 12 can be easily cut, and the outer cover 13 can be easily removed. Further, by including a non-woven fabric in the release layer 12, it is possible to prevent the generation of fine scraps of the release layer 12 being torn when removing the outer cover 13.

[0068] When the release layer 12 includes a non-woven fabric, the non-woven fabric can contain fibers 20 having a core-sheath structure including a core 21 and a sheath 22 disposed outside the core 21, as shown in FIG. 2. The core 21 and the sheath 22 may be made of the same material or different materials. FIG. 2 is a perspective view showing a part of the fibers 20 having a core-sheath structure so that a cross-section in a plane passing through the central axis can be seen.

[0069] Since the fibers contained in the non-woven fabric have a core-sheath structure, by selecting the materials of the core 21 and the sheath 22, it is possible to obtain fibers that can satisfy the properties required for the fibers and the non-woven fabric. For example, by using different materials for the core 21 and the sheath 22, the properties of the fibers 20 and the non-woven fabric containing the fibers 20 can be easily controlled.

[0070] For example, by using a material with a relatively high melting temperature such as polyethylene terephthalate for the core 21 and a material with a relatively low melting temperature such as polyethylene for the sheath 22, fibers 20 with a low melting temperature can be obtained. Therefore, the non-woven fabric containing the fibers 20 can also have a low melting temperature. (3) Outer Cover The outer cover 13 can cover the release layer 12 and can be disposed so as to be in direct contact with the release layer 12.

[0071] By having the outer sheath 13, the multi-core cable 10 protects the electric wires 11 included in the core 110 and enhances durability. (Resin material) The outer sheath 13 can include a resin material. The resin material is not particularly limited. For example, polyolefin resins such as polyethylene and ethylene-vinyl acetate copolymer (EVA), polyurethane elastomers (polyurethane resins) such as thermoplastic polyurethane elastomer (TPU), polyester elastomers, or a composition formed by mixing at least two of these can be used.

[0072] As shown in FIG. 1, the outer sheath 13 can also include a plurality of layers such as a first outer sheath 131 and a second outer sheath 132 in order from a position close to the core 110. The outer sheath 13 is not limited to the form of two layers shown in FIG. 1, and can be a single layer or can include a plurality of layers of three or more layers. The first outer sheath 131 and the second outer sheath 132 can be made of different materials or can be made of the same material.

[0073] The materials of the first outer sheath 131 and the second outer sheath 132 are not particularly limited, and can contain the resin materials described as the materials of the outer sheath 13.

[0074] The first outer sheath 131 can contain, for example, as a resin material, one or more selected from polyurethane resin and polyolefin resins.

[0075] The second outer sheath 132 can contain, for example, as a resin material, a polyurethane resin having excellent abrasion resistance. Since the second outer sheath 132 is arranged to cover the outer surface of the multi-core cable 10, by including a polyurethane resin as the resin material in the second outer sheath 132, the durability of the multi-core cable 10 can be enhanced. (Additive) In addition to the above resin materials, the outer sheath 13 can also contain one or more additives selected from flame retardants, antioxidants, anti-degradants, acid acceptors, colorants, crosslinking agents, crosslinking aids, processing aids, fillers, lubricants, etc.

Example

[0076] Specific examples will be given below for explanation, but the present invention is not limited to these examples. (Evaluation method) First, the evaluation method of the electric wire produced in the following experimental examples will be described. (1) Processability test As shown in Fig. 3, at the end 10A of the multi-core cable 10, a cut 31 reaching the release layer 12 was made at a point 408 mm from the end 10A (first step). Next, the outer sheath 13 was pulled along the longitudinal direction of the multi-core cable 10 as shown by the block arrow 32, and the outer sheath 13 was removed (second step).

[0077] In the second step, if the outer sheath on the end side could be removed, it was evaluated as A. In the second step, if the outer sheath on the end side could not be removed, it was evaluated as B. (2) Melting temperature The melting temperatures of the release layer 12 and the first outer sheath 131 were evaluated by heating using a DSC under the condition of a heating rate of 10 °C / min from room temperature (25 °C). In the obtained DSC curve, the peak temperature of the first appearing endothermic peak was taken as the melting temperature.

[0078] (3) Tensile strength For the non-woven fabric used for the release layer 12, the tensile strength was measured using a tensile tester in accordance with JIS L 1913 (2010).

[0079] (Regarding the manufacturing conditions of the multi-core cable) The multi-core cables in each experimental example will be described below.

[0080] Experimental Example 1 and Experimental Example 2 are examples, and Experimental Example 3 is a comparative example. [Experimental Example 1, Experimental Example 2] A multi-core cable having the same structure as the multi-core cable 10 shown in Fig. 1 was produced in a cross-section perpendicular to the longitudinal direction.

[0081] The materials used for the release layer, the first outer sheath, and the second outer sheath are shown in the composition column of Table 1.

[0082] The release layer 12 was formed by spirally winding a non-woven tape made of fibers having a core-sheath structure in which the core is polyethylene terephthalate and the sheath covering the core is polyethylene around the core 110. In Experimental Example 2, there is no distinction between the first outer covering and the second outer covering, and there is one layer of an outer covering of thermoplastic polyurethane elastomer.

[0083] The evaluation results of the tensile strength, melting temperature (T12, T121) of the release layer 12, and melting temperature (T13) of the first outer covering 131 are also shown in the composition column of Table 1. The melting temperatures T12 and T121 of the release layer 12 are the melting temperatures of the polyethylene used for the sheath.

[0084] When observing the cross-section of the obtained multi-core cable, it was confirmed that the release layer 12 was fixed to the outer covering 13.

[0085] The evaluation results are shown in Table 1. [Experimental Example 3] A multi-core cable was manufactured and evaluated under the same conditions as in Experimental Example 1, except that the materials of the release layer 12 and the first outer covering 131 were changed. The evaluation results are shown in Table 1.

[0086]

Table 1

Explanation of Symbols

[0087] 10 Multi-core cable 10A End 11 Electric wire 110 Core 110A Outer surface 11A Conductor 11B Insulator 11C Conductor strand 111 First electric wire 111A First conductor 111B First insulator 111C First conductor strand 112 Second electric wire 112A Second conductor 112B Second insulator 112C Second conductor strand 1120 Twisted pair wire 12 Release layer 12A Surface 13 Outer sheath 131 First outer sheath 131A Surface 132 Second outer sheath 14 Coating layer 141 First coating layer 142 Second coating layer 20 Fiber 21 Core 22 Sheath 31 Notch 32 Block arrow L13 Length

Claims

1. a core formed by twisting a plurality of electric wires; a release layer covering the core; a jacket covering the release layer, and having: the tensile strength of the release layer being 10 MPa or more and 38 MPa or less; a multi-core cable in which the release layer is fixed to the jacket.

2. The multi-core cable according to claim 1, wherein the difference between the melting temperature of the material contained in the surface of the release layer in contact with the jacket and the melting temperature of the material contained in the surface of the jacket in contact with the release layer is 60°C or less.

3. The release layer includes a plurality of materials; The multi-core cable according to claim 1, wherein the difference between the melting temperature of at least a part of the materials contained in the surface of the release layer in contact with the jacket and the melting temperature of the material contained in the surface of the jacket in contact with the release layer is 60°C or less.

4. The multi-core cable according to claim 1 or claim 2, wherein the release layer includes a non-woven fabric.

5. The multi-core cable according to claim 4, wherein the non-woven fabric contains fibers having a core-sheath structure including a core and a sheath disposed outside the core.

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