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CN-116075905-B - Core wire for multi-core cable, and multi-core cable with sensor

CN116075905BCN 116075905 BCN116075905 BCN 116075905BCN-116075905-B

Abstract

The core wire for a multi-core cable comprises a conductor, a first insulating film covering the outer periphery of the conductor and comprising a polyethylene resin, and a second insulating film in contact with the outer periphery of the first insulating film and comprising a copolymer of ethylene and an alpha-olefin having a carbonyl group.

Inventors

  • KU XIANZHI
  • Song Tianji
  • TANAKA SHIGEYUKI

Assignees

  • 住友电气工业株式会社

Dates

Publication Date
20260505
Application Date
20210601
Priority Date
20200831

Claims (8)

  1. 1. A core wire for a multi-core cable, comprising: A conductor stranded with a plurality of wires; a first insulating film covering the outer periphery of the conductor and containing polyethylene resin, and A second insulating film provided in contact with the outer periphery of the first insulating film and comprising a copolymer of ethylene and an alpha-olefin having a carbonyl group, The average thickness of the first insulating film is equal to or greater than the average thickness of the second insulating film, and the average thickness of the first insulating film is equal to or greater than 0.11mm, The polyethylene resin accounts for more than 30 mass% of the resin component contained in the first insulating film, The first insulating film has a melting point of 110 ℃ or more and 140 ℃ or less, The proportion of the copolymer in the resin component of the second insulating film is 50% by mass or more, the content of the other resin in the resin component of the second insulating film is 30% by mass or less, The second insulating film has a melting point lower than that of the first insulating film.
  2. 2. The core wire for a multi-core cable according to claim 1, wherein, The content of the polyethylene resin in the first insulating film is higher than the content of the polyethylene resin in the second insulating film.
  3. 3. The core wire for a multi-core cable according to claim 1 or 2, wherein, The proportion of the carbonyl group-containing alpha olefin in the copolymer is 9 mass% or more and 33 mass% or less.
  4. 4. The core wire for a multi-core cable according to claim 1 or 2, wherein, The second insulating film contains an ethylene-vinyl acetate copolymer as the copolymer.
  5. 5. The core wire for a multi-core cable according to claim 4, wherein, The resin component contained in the second insulating film is only an ethylene-vinyl acetate copolymer.
  6. 6. A core wire for a multi-core cable, comprising: A conductor stranded with a plurality of wires; a first insulating film covering the outer periphery of the conductor and containing polyethylene resin, and A second insulating film provided in contact with the outer periphery of the first insulating film and comprising a copolymer of ethylene and vinyl acetate, The proportion of the vinyl acetate in the copolymer is 12 mass% or more and 25 mass% or less, The average thickness of the first insulating film is equal to or greater than the average thickness of the second insulating film, and the average thickness of the first insulating film is equal to or greater than 0.11mm, The polyethylene resin accounts for more than 30 mass% of the resin component contained in the first insulating film, The first insulating film has a melting point of 110 ℃ or more and 140 ℃ or less, The proportion of the copolymer in the resin component of the second insulating film is 50% by mass or more, the content of the other resin in the resin component of the second insulating film is 30% by mass or less, The second insulating film has a melting point lower than that of the first insulating film.
  7. 7. A multi-core cable, having: A core wire twisted with a plurality of core wires, and A sheath layer arranged around the core wire, At least one of the plurality of core wires is the core wire for a multi-core cable according to any one of claims 1 to 6.
  8. 8. A multi-core cable with a sensor, having: The multi-core cable of claim 7, and A sensor connected to the conductors of the plurality of core wires exposed from the first insulating film and the second insulating film, The multi-core cable with a sensor includes a sealing resin for sealing a portion of the conductor exposed from the first insulating film and the second insulating film.

Description

Core wire for multi-core cable, and multi-core cable with sensor Technical Field The present disclosure relates to a core wire for a multi-core cable, and a multi-core cable with a sensor. The present application claims priority based on japanese patent application No. 2020-145936 of 31/8/2020, and incorporates all of the descriptions described in the above japanese patent application. Background In factory automation (factory automation:FA), FA sensors such as photoelectric sensors and proximity sensors for detecting positions are used. The cable connected to the FA sensor includes a plurality of core wires (insulated wires), one end of which is connected to the FA sensor. The connection portion of the core wire with the FA sensor is sealed with a sealing resin so as to include an insulating film of the core wire. As a cable for such use, an electric wire whose terminal is covered with a molded resin molded body composed of a polybutylene terephthalate resin or a polyamide resin is disclosed (patent document 1). Prior art literature Patent literature Patent document 1 Japanese patent application laid-open No. 2017-212224 Disclosure of Invention The core wire for a multi-core cable of the present disclosure includes a conductor in which a plurality of wires are stranded, a first insulating film covering an outer periphery of the conductor and including a polyethylene-based resin, and a second insulating film provided in contact with the outer periphery of the first insulating film and including a copolymer of ethylene and an alpha olefin having a carbonyl group. Drawings Fig. 1 is a cross-sectional view showing a multicore cable according to a first embodiment. Fig. 2 is a schematic diagram showing a multi-core cable with a sensor according to a second embodiment. Fig. 3 is a schematic diagram of a multi-core cable with a sensor according to a modification of the second embodiment. Detailed Description [ Problem to be solved by the present disclosure ] The cable connected to the FA sensor may be used in an environment where oil splashed in a factory adheres. When oil adheres to the cable and penetrates the insulating layer to reach the conductor, short circuits or the like may occur, and the operation of the sensor may be affected. The purpose of the present disclosure is to provide a core wire for a multi-core cable, and a multi-core cable with a sensor, which can improve oil resistance as compared with conventional ones. [ Effect of the present disclosure ] According to the present disclosure, oil resistance can be improved. Hereinafter, embodiments for implementation will be described. [ Description of embodiments of the present disclosure ] First, embodiments of the present disclosure are listed and described. The core wire for a multi-core cable according to one embodiment of the present disclosure includes a conductor in which a plurality of wires are twisted, a first insulating film covering an outer periphery of the conductor and including a polyethylene resin, and a second insulating film provided in contact with the outer periphery of the first insulating film and including a copolymer of ethylene and an alpha olefin having a carbonyl group. The first insulating film contains a polyethylene resin and has excellent oil resistance. The sensor may be connected to a multi-core cable including a core wire for the multi-core cable, and a connection portion between the multi-core cable and the sensor may be sealed with a sealing resin. However, good adhesion (epoxy resin adhesion) is not easily obtained between the polyethylene resin and the epoxy resin suitable for the sealing resin. In contrast, in the core wire for a multi-core cable according to one embodiment of the present disclosure, the second insulating film includes a copolymer of ethylene and an α -olefin having a carbonyl group. The copolymer has excellent adhesion with the epoxy resin. Therefore, good adhesion with the sealing resin can be ensured while obtaining good oil resistance. In [ 2], the second insulating film may have a melting point lower than that of the first insulating film in [ 1 ]. In this case, good bending resistance is easily obtained. In the case of [ 1] or [ 2 ], the content of the polyethylene resin in the first insulating film may be higher than the content of the polyethylene resin in the second insulating film. In this case, good oil resistance is obtained, and good adhesion to the sealing resin is easily ensured. In [1 ] to [ 3 ], the average thickness of the first insulating film may be equal to or greater than the average thickness of the second insulating film. In this case, good oil resistance is obtained, and good adhesion to the sealing resin is easily ensured. In [ 5] of [ 1] to [4 ], the proportion of the carbonyl group-containing alpha olefin in the copolymer may be 9% by mass or more and 33% by mass or less. In this case, good mechanical properties are easily obtained while ensuring good adhesion to the se