WO2022190851A1

WO2022190851A1 - Electric wire for communication

Info

Publication number: WO2022190851A1
Application number: PCT/JP2022/007150
Authority: WO
Inventors: 悠太安好
Original assignee: 株式会社オートネットワーク技術研究所; 住友電装株式会社; 住友電気工業株式会社
Priority date: 2021-03-08
Filing date: 2022-02-22
Publication date: 2022-09-15
Also published as: JP2022136460A

Abstract

The present invention provides an electric wire for communication, the electric wire being not susceptible to the occurrence of a defect in a magnetic sheath layer that contains a powdered magnetic material even in cases where the magnetic sheath layer is formed thin.　An electric wire 1 for communication, the electric wire 1 comprising a conductor 2, an insulating layer 3 that covers the outer circumference of the conductor 2, and a magnetic sheath layer 8 that covers the outside of the insulating layer 3, wherein: the magnetic sheath layer 8 contains an organic polymer and a powdered magnetic material; the content of the magnetic material in the magnetic sheath layer 8 is from 350 parts by mass to 850 parts by mass relative to 100 parts by mass of the organic polymer; and the composition that constitutes the magnetic sheath layer 8 has a melt flow rate of 11.8 g/10 minutes or more as measured at 230°C under a load of 2.16 kg.

Description

Telecommunication wire

This disclosure relates to communication wires.

In some cases, communication wires used in fields such as automobiles are provided with a shield layer on the outside of the core wire for the purpose of reducing the intrusion of noise from the outside and the emission of noise to the outside. An example of such a shield layer is a sheath layer that covers the outer periphery of a core wire using a material in which a powdery magnetic material is dispersed in an organic polymer. A communication wire provided with a sheath layer containing such a magnetic material is disclosed in Patent Documents 1 and 2, for example.

JP 2016-197509 A JP-A-3-88214

When a magnetic sheath layer in which magnetic material powder is dispersed in an organic polymer is arranged around the outer circumference of a communication wire, the magnetic sheath layer must contain a sufficient amount of magnetic material in order to obtain sufficiently high noise shielding performance. must be included. However, if the magnetic sheath layer contains a large amount of magnetic material, the mass of the magnetic sheath layer and the mass of the communication wire as a whole increase. When a communication wire is mounted on an automobile, it is preferable to keep the mass of the communication wire small.

From the viewpoint of suppressing an increase in the mass of the magnetic sheath layer, it is conceivable to form the magnetic sheath layer thin. If the concentration of the magnetic material in the magnetic sheath layer is sufficiently high, a sufficiently high noise shielding property should be obtained even if the magnetic sheath layer is made thin. However, when the magnetic material is contained in the magnetic sheath layer at a high concentration, the extrusion moldability of the magnetic sheath layer deteriorates. more likely to occur. These defects can cause deterioration of the noise shielding performance of the magnetic sheath layer.

In view of the above, it is an object of the present invention to provide a communication wire in which defects are less likely to occur in the magnetic sheath layer even if the magnetic sheath layer containing a powdery magnetic material is formed thin.

A communication wire according to the present disclosure includes a conductor, an insulating layer covering the outer circumference of the conductor, and a magnetic sheath layer covering the outside of the insulating layer, the magnetic sheath layer comprising an organic polymer, and a powdery magnetic material, the content of the magnetic material in the magnetic sheath layer is 350 parts by mass or more and 850 parts by mass or less with respect to 100 parts by mass of the organic polymer, and the magnetic sheath The composition constituting the layer has a melt flow rate of 11.8 g/10 minutes or more measured at 230° C. with a load of 2.16 kg.

A communication wire according to the present disclosure is a communication wire in which defects are less likely to occur in the magnetic sheath layer even if the magnetic sheath layer containing the powdered magnetic material is formed thin.

FIG. 1 is a cross-sectional view showing the configuration of a communication wire according to one embodiment of the present disclosure.

[Description of Embodiments of the Present Disclosure]
First, embodiments of the present disclosure will be described.
A communication wire according to the present disclosure includes a conductor, an insulating layer covering the outer circumference of the conductor, and a magnetic sheath layer covering the outside of the insulating layer, the magnetic sheath layer comprising an organic polymer, and a powdery magnetic material, the content of the magnetic material in the magnetic sheath layer is 350 parts by mass or more and 850 parts by mass or less with respect to 100 parts by mass of the organic polymer, and the magnetic sheath The composition constituting the layer has a melt flow rate of 11.8 g/10 minutes or more measured at 230° C. with a load of 2.16 kg.

In the above communication wire, the magnetic sheath layer contains a large amount of magnetic material, 350 parts by mass or more and 850 parts by mass or less, with respect to 100 parts by mass of the organic polymer. However, since the composition constituting the magnetic sheath layer has a high melt flow rate of 11.8 g/10 minutes or more, it exhibits high extrusion moldability. Therefore, when forming the magnetic sheath layer by extrusion molding, even if the thickness of the magnetic sheath layer is reduced, the magnetic sheath layer can be obtained with few defects such as holes. By forming a magnetic sheath layer that is small in thickness, contains a large amount of magnetic material, and has few defects, it is possible to achieve both noise shielding performance and lightness in a communication wire.

Here, the composition constituting the magnetic sheath layer preferably has a melt flow rate of 23.9 g/10 minutes or less measured under a load of 2.16 kg at 230°C. As a result, the magnetic sheath layer has high low-temperature shock resistance, and the electric wire for communication can be suitably used even in places where there is a possibility of being exposed to low temperatures, such as in automobiles.

The thickness of the magnetic sheath layer is preferably 0.12 mm or more and 0.16 mm or less. As a result, the electric wire for communication is excellent in both noise shielding performance and lightness.

The mass per unit length of the magnetic sheath layer is preferably 3 g/m or less. Then, it is possible to effectively reduce the weight of the communication wire.

The communication wire may be configured as a coaxial wire having a metal shield layer on the outer periphery of the insulating layer, and the magnetic sheath layer may be provided on the outer periphery of the metal shield layer. A communication wire configured as a coaxial wire is susceptible to noise, but by providing the magnetic sheath layer, the influence of noise can be reduced. By using the above composition for the magnetic sheath layer, it is possible to achieve both sufficient noise shielding performance and thinning of the magnetic sheath layer by suppressing the generation of defects. Providing the metal shield layer tends to increase the mass of the communication wire as a whole, but by forming the magnetic sheath layer thin, it is possible to suppress an increase in the mass of the communication wire as a whole.

[Details of the embodiment of the present disclosure]
A communication wire according to an embodiment of the present disclosure will be described in detail below with reference to the drawings. Hereinafter, melt flow rate (MFR) refers to a value measured at 230° C. with a load of 2.16 kg. Unless otherwise specified, other properties are values measured at room temperature in the atmosphere. Organic polymers also include polymers with a relatively low degree of polymerization, such as oligomers.

(Overall configuration of communication wire)
FIG. 1 shows a cross-sectional view of a communication wire 1 according to an embodiment of the present disclosure, cut perpendicularly to the axial direction. The communication wire 1 is configured as a coaxial wire. Specifically, the communication wire 1 includes a core wire 4 having a conductor 2 and an insulating layer 3 covering the outer circumference of the conductor 2 . A metal foil 5 and a braided layer 6 formed by braiding metal wires are provided as a metal shield layer 7 around the outer circumference of the core wire 4 . A metal foil 5 is provided to cover the outer periphery of the core wire 4 , and a braided layer 6 is provided to cover the outer periphery of the metal foil 5 . A magnetic sheath layer 8 containing a magnetic material is provided around the metal shield layer 7 . Furthermore, an outer sheath layer 9 containing no magnetic material is provided around the outer periphery of the magnetic sheath layer 8 .

The communication wire 1 as described above, which is configured as a coaxial wire having a metal shield layer 7 and a magnetic sheath layer 8 on the outer periphery of the core wire 4, is suitable for transmitting signals in a high frequency range of 1 GHz or higher. can be used for However, the communication wire according to the present disclosure is not limited to having the above structure as long as the outer side of the core wire 4 is covered and the magnetic sheath layer 8 is provided. An appropriate configuration may be adopted. The magnetic sheath layer 8 may cover the outer circumference of the core wire 4 directly, or may cover the outer circumference of the core wire 4 with another layer interposed like the metal shield layer 7 described above. good too.

For example, in the above embodiment, a single insulated wire is used as the core wire 4, but a plurality of insulated wires may be used. Specifically, the core wire 4 can be configured such that a pair of insulated wires are twisted together or run in parallel to transmit a differential signal. If the influence of noise is not so great, only one of the metal foil 5 and the braided layer 6 may be arranged as the metal shield layer 7, or the metal shield layer 7 may be omitted. good too. Further, as the metal shield layer 7, a form other than the metal foil 5 and the braided layer 6, such as a horizontally wound wire, may be used. The outer sheath layer 9 may also be omitted if the function such as protection of the magnetic sheath layer 8 is not so required. Further, in the above embodiment, each of the layers described above is formed in direct contact with the outer periphery of the inner constituent layer, but the communication wire may appropriately include constituent layers other than the layers described above. There may be. Hereinafter, each constituent member of the coaxial communication wire 1 illustrated above will be described in detail.

(core wire)
The core wire 4 is a signal wire responsible for transmission of electrical signals in the communication wire 1 and has a conductor 2 and an insulating layer 3 covering the outer periphery of the conductor 2 . The materials forming the conductor 2 and the insulating layer 3 are not particularly limited.

Various metal materials can be used as the material for the conductor 2, but it is preferable to use a copper alloy because of its high conductivity. Although the conductor 2 may be configured as a single wire, it is preferably configured as a stranded wire in which a plurality of strands (for example, seven wires) are twisted together from the viewpoint of enhancing flexibility when bending. In this case, after twisting the strands, compression molding may be performed to form a compressed stranded wire. When the conductor 2 is configured as a stranded wire, all of them may be made of the same wire, or two or more kinds of wire may be included. The diameter of the conductor 2 is not particularly limited. The conductor cross-sectional area can be exemplified in the range of 0.05 mm ² or more and 1.0 mm ² or less.

The insulating layer 3 insulates the conductor 2 in the core wire 4 and contains an organic polymer. The type of organic polymer is not particularly limited, but examples include olefin polymers such as polyolefins and olefin copolymers, halogen polymers such as polyvinyl chloride, various engineering plastics, elastomers, and rubbers. . The organic polymers may be used singly or in combination of two or more by mixing, laminating, or the like. The organic polymer may be crosslinked or foamed.

From the viewpoint of improving communication characteristics, it is preferable to use low-molecular-weight polar organic polymers among those listed above as the organic polymer constituting the insulating layer 3 . For example, it is preferable that the insulating layer 3 includes a non-polar organic polymer such as polyolefin such as polypropylene (PP). As the polyolefin, homopolyolefin such as homo PP may be used, or block polyolefin such as block PP may be used.

The insulating layer 3 may contain additives as appropriate in addition to the organic polymer. Examples of additives include flame retardants such as metal hydroxides, copper damage inhibitors, hindered phenol-based and sulfur-based antioxidants, and metal oxides such as zinc oxide. However, it is preferable that the insulating layer 3 does not contain an additive made of a magnetic material such as that contained in the magnetic sheath layer 8 . Although the thickness of the insulating layer 3 is not particularly limited, a range of 0.1 mm or more and 1.0 mm or less can be exemplified.

(metal shield layer)
The metal shield layer 7 is provided between the core wire 4 and the magnetic sheath layer 8, and has a two-layer structure in which the metal foil 5 and the braided layer 6 are laminated.

The metal foil 5 is configured as a thin film of a metal material. The type of metal forming the metal foil 5 is not particularly limited, and examples thereof include copper, copper alloys, aluminum, aluminum alloys, and the like. The metal foil 5 may be composed of a single kind of metal, or may be a laminate of layers of two or more kinds of metals. The metal foil 5 may be formed of an independent metal thin film, or may be formed by bonding a metal layer to a base material such as a polymer film by vapor deposition, plating, adhesion, or the like. From the viewpoint of enhancing noise shielding properties, it is preferable to arrange the metal foil 5 in a tandem manner with respect to the core wire 4 .

The braided layer 6 is configured as a braided body in which a plurality of metal wires are woven together to form a hollow tubular shape. Examples of the metal wires forming the braided layer 6 include metal materials such as copper, copper alloys, aluminum, and aluminum alloys, and metal materials whose surfaces are plated with tin or the like.

The metal shield layer 7 constitutes an outer conductor in the coaxial cable structure, and plays a role of shielding noise entering the core wire 4 and noise emitted from the core wire 4 . As will be described later, in the communication wire 1, the noise shielding effect is also exhibited by the magnetic sheath layer 8. The influence of noise tends to become serious, and by providing the metal shield layer 7 together with the magnetic sheath layer 8, the influence of noise can be effectively reduced. By using both the metal foil 5 and the braided layer 6 as the metal shield layer 7, the noise shielding effect can be enhanced. Although the order of lamination of the metal foil 5 and the braided layer 6 is not particularly limited, it is preferable to arrange the metal foil 5 inside and the braided layer 6 outside for reasons such as reducing signal loss.

(Magnetic sheath layer)
The magnetic sheath layer 8 covers the outer circumference of the core wire 4 . In this embodiment, the magnetic sheath layer 8 covers the outer periphery of the core wire 4 with the metal shield layer 7 interposed therebetween.

The magnetic sheath layer 8 contains a powdery magnetic material and an organic polymer component. The magnetic material powder is dispersed in a matrix composed of organic polymer components. The magnetic material contained in the magnetic sheath layer 8 is preferably a ferromagnetic material, more preferably a metal or metal compound having soft magnetism. By containing a magnetic material, particularly a soft magnetic material, in the magnetic sheath layer 8, the communication wire 1 can obtain an excellent noise shielding effect. That is, electromagnetic waves from the outside of the communication wire 1 enter the communication wire 1 and become noise, affecting the signal transmitted through the core wire 4. It is possible to suppress the phenomenon that the resulting electromagnetic wave is emitted to the outside of the communication wire 1 . This is because magnetic loss in the magnetic material contained in the magnetic sheath layer 8 absorbs and attenuates high-frequency electromagnetic waves that can cause noise. In the communication wire 1, the noise shielding effect is exhibited also by the metal foil 5 and the braided layer 6, but when the communication wire 1 is used for communication in a high frequency range such as 1 GHz or higher, the influence of noise is large. It is likely to become serious, and by providing the magnetic sheath layer 8 together with the metal foil 5 and the braided layer 6, the influence of noise can be effectively reduced.

(1) Magnetic materials Iron (pure iron or iron containing a small amount of carbon), Fe—Si alloy (silicon steel), Fe—Si Magnetic stainless steel such as -Al alloy (sendust), Fe--Cr--Al--Si alloy, Fe--Si--Cr alloy, Fe--Ni system alloy (permalloy), ferrite and the like can be exemplified. Among these materials, it is particularly preferable to use ferrite because of its excellent noise shielding properties and low cost. As the ferrite, a Ni--Zn-based ferrite can be particularly suitably used. The magnetic materials may be used singly or in combination of two or more by mixing or the like. The particle size of the particles of the magnetic material contained in the magnetic sheath layer 8 is not particularly limited, but the average particle size is preferably 0.1 μm or more and 100 μm or less.

The content of the magnetic material in the magnetic sheath layer 8 is 350 parts by mass or more and 850 parts by mass or less when the entire organic polymer component constituting the magnetic sheath layer 8 is 100 parts by mass. By containing 350 parts by mass or more of the magnetic material with respect to 100 parts by mass of the organic polymer component, the magnetic sheath layer 8 can sufficiently improve the noise shielding performance due to the absorption of electromagnetic waves by the magnetic material. It is more preferable that the content of the magnetic material is 400 parts by mass or more in order to enhance the noise shielding performance of the magnetic sheath layer 8 .

On the other hand, since the content of the magnetic material in the magnetic sheath layer 8 is suppressed to 850 parts by mass or less with respect to 100 parts by mass of the organic polymer component, an increase in the mass of the magnetic sheath layer 8 can be suppressed. In addition, the extrudability of the composition forming the magnetic sheath layer 8 can be enhanced. From the viewpoint of further enhancing those effects, the content of the magnetic material is more preferably 800 parts by mass or less. In the following also, the content in units of parts by mass of each constituent component of the magnetic sheath layer 8 is expressed as 100 parts by mass of the entire organic polymer component forming the magnetic sheath layer 8 .

(2) Organic polymer component The material forming the magnetic sheath layer 8 contains an organic polymer. A specific type of the organic polymer is not particularly limited as long as the composition as a whole constituting the magnetic sheath layer 8 gives an MFR within a predetermined range, which will be described later. Examples of organic polymers that can be used for the magnetic sheath layer 8 include olefin-based polymers such as polyolefins and olefin-based copolymers, halogen-based polymers such as polyvinyl chloride, various engineering plastics, as well as the insulating layer 3 of the core wire 4 . Elastomers, rubbers and the like can be mentioned. The organic polymers may be used singly or in combination of two or more by mixing or the like. The organic polymer may be crosslinked or foamed.

The magnetic sheath layer 8 preferably contains an elastomer, particularly an olefinic thermoplastic elastomer (TPO), among those listed above. Elastomers such as TPO increase the flexibility of the magnetic sheath layer 8 . The content of the elastomer should be 20% by mass or more and 40% by mass or less of the total organic polymer components constituting the magnetic sheath layer 8 .

Further, the magnetic sheath layer 8 preferably contains polyolefin such as polypropylene (PP) in addition to elastomer such as TPO. Polyolefin tends to exhibit low viscosity when melted, and enhances the extrusion moldability of the magnetic sheath layer 8 . As the polyolefin, either homopolyolefin such as homo PP or block polyolefin such as block PP may be used. Block polyolefins are preferably used. From the viewpoint of increasing the MFR of the composition constituting the magnetic sheath layer 8 as a whole, the polyolefin preferably has an MFR of 30 g/10 minutes or more, more preferably 50 g/10 minutes or more. The polyolefin content is preferably 20% by mass or more and 40% by mass or less in the organic polymer component. In addition, it is preferable that the total amount of the elastomer and the polyolefin is 50% by mass or more of the organic polymer component.

Other than elastomers and polyolefins, suitable examples of organic polymer components contained in the magnetic sheath layer 8 include ethylene-ethyl acrylate copolymer (EEA), ethylene-methyl acrylate copolymer (EMA), and ethylene-acetic acid. Ethylene-based copolymers such as vinyl copolymers (EVA), acid-modified polymers, and the like can be mentioned. These ethylene-based copolymers and acid-modified polymers are effective in enhancing adhesion between the organic polymer component and the magnetic material powder. In addition to the magnetic material and the organic polymer, the magnetic sheath layer 8 may contain additives as appropriate. Examples of additives include flame retardants, copper damage inhibitors, antioxidants, metal oxides, and the like.

(3) Physical Properties of Magnetic Sheath Layer The composition forming the magnetic sheath layer 8 has an MFR of 11.8 g/10 minutes or more measured at 230° C. under a load of 2.16 kg. The composition constituting the magnetic sheath layer 8 has a high MFR, so that it has high extrusion moldability, and the magnetic sheath layer 8 having a highly uniform structure can be formed by extrusion molding.

If the MFR of the composition constituting the magnetic sheath layer 8 is too low, the material has a high viscosity when forming the magnetic sheath layer 8 by extrusion. If there is a possibility that the material will not stretch and break in the vicinity of the ejection port of the molding device, then a hole in which the material is partially missing may occur in the formed magnetic sheath layer 8 . However, when the composition constituting the magnetic sheath layer 8 has an MFR of 11.8 g/10 minutes or more, the extrusion molding can proceed smoothly, and the magnetic material has a dense structure and a smooth surface. A sheath layer 8 can be formed. As a result, although the magnetic sheath layer 8 contains a large amount of magnetic material of 350 parts by mass or more, defects such as holes occur in the magnetic sheath layer 8 even when the magnetic sheath layer 8 is formed thin. Hateful. Then, in the magnetic sheath layer 8, penetration and emission of electromagnetic waves through defects are less likely to occur, and in the communication wire 1, high noise shielding properties can be ensured.

In the communication wire 1, by forming the magnetic sheath layer 8 thin while ensuring sufficient noise shielding performance, it is possible to suppress an increase in the mass of the magnetic sheath layer 8 and further the mass of the communication wire 1 as a whole. can. When the communication wire 1 is mounted on a moving object such as an automobile, it is very important to suppress an increase in mass. In particular, the communication wire 1 according to the present embodiment includes the metal shield layer 7 made up of the metal foil 5 and the braided layer 6. These contribute to increase the mass of the communication wire 1, but the magnetic field By reducing the weight of the sheath layer 8, an increase in the mass of the communication wire 1 as a whole can be suppressed. From the viewpoint of effectively achieving thinning of the magnetic sheath layer 8 by improving extrusion moldability, the MFR of the composition constituting the magnetic sheath layer 8 is 15 g/10 minutes or more, further 17 g/10 minutes or more. is more preferable. The MFR of the magnetic sheath layer 8 can be adjusted by the type of organic polymer forming the magnetic sheath layer 8, the content of the magnetic material, and the like.

From the viewpoint of improving extrusion moldability, the upper limit of the MFR of the composition forming the magnetic sheath layer 8 is not particularly limited. However, the low-temperature impact resistance of the magnetic sheath layer 8 can be enhanced by keeping the MFR low to some extent. The longer the molecular chain and the more branched the organic polymer, the lower the MFR. , the glass transition temperature is lowered. A material with a lower glass transition temperature has a higher low temperature impact resistance. When the communication wire 1 is used in a place where there is a possibility of being exposed to a low-temperature environment, such as in an automobile, the MFR of the composition constituting the magnetic sheath layer 8 is, for example, 23.9 g/10 min or less, and further is preferably kept low to some extent, such as 20 g/10 minutes or less. Since the magnetic sheath layer 8 has a high low-temperature impact resistance, it is less likely to be damaged such as broken even when subjected to an impact in a low-temperature environment, and high noise shielding properties can be maintained. It should be noted that high low-temperature impact resistance is not essential for the communication wire 1 of the present disclosure, and may not be provided when use in a low-temperature environment is not assumed.

(4) Thickness of the magnetic sheath layer As described above, the composition constituting the magnetic sheath layer 8 has a high MFR of 11.8 g/10 min or more, thereby suppressing the formation of defects such as holes. , the magnetic sheath layer 8 can be formed thin. The specific thickness of the magnetic sheath layer 8 is not particularly limited, but the effect of suppressing defect generation by increasing the MFR of the magnetic sheath layer 8 can be obtained, and the thickness can be effectively reduced by thinning. 0.16 mm or less is preferable from the viewpoint of achieving . Further, the thickness of the magnetic sheath layer 8 is set so that the mass of the magnetic sheath layer 8 per unit length of the communication wire 1 is 4 g/m or less, further 3 g/m or less, or 2 g/m or less. do it. Although the lower limit of the thickness of the magnetic sheath layer 8 is not particularly defined from the viewpoint of mass reduction, it is preferable to set it at 0.12 mm or more from the viewpoint of ensuring high noise shielding properties. Further, it is preferable that the mass of the magnetic sheath layer 8 per unit length is 1.5 g/m or more. The relationship between the thickness d (unit: mm) of the magnetic sheath layer 8 and the mass A (unit: g/m) of the magnetic sheath layer 8 per unit length can be determined by the following formula (1). .

Here, ρ is the density of the composition forming the magnetic sheath layer 8 (unit: g/cm ³ ), and R ₀ is the inner diameter of the magnetic sheath layer 8 (unit: mm).

Even if the total amount of the magnetic material contained in the magnetic sheath layer 8 is the same, the magnetic sheath having a smaller thickness containing a high concentration of the magnetic material than the thick magnetic sheath layer 8 containing a low concentration of the magnetic material. Layer 8 is more effective in noise shielding. The specific magnetic material content and the thickness of the magnetic sheath layer 8 may be appropriately set within a range of 350 parts by mass or more and 850 parts by mass or less according to the required noise shielding property. Just do it. For noise shielding performance to be targeted, for example, in a radiated emission evaluation based on CISPR25 (the standard of "recommended limit values and measurement methods of interference waves for protection of vehicle-mounted receivers" by the International Special Committee on Radio Interference), A level at which the amount of noise emission at a frequency of 1.6 GHz is less than 16 dB (μV/m), and further less than 10 dB (μV/m) can be exemplified.

As a specific example of the relationship between the thickness of the magnetic sheath layer 8 and the content of the magnetic material, the following relationship can be exemplified.
・Thickness of 0.12 mm or more and less than 0.13 mm: Content of more than 650 parts by mass and less than 850 parts by mass ・Thickness of 0.13 mm or more and less than 0.14 mm: Content of more than 550 parts by mass and less than 650 parts by mass ・Thickness 0.14 mm or more and 0.16 mm or less: content of 350 parts by mass or more and 550 parts by mass or less

(outer sheath layer)
The outer sheath layer 9 is a layer provided to cover the outer periphery of the magnetic sheath layer 8 and is exposed to the outer periphery of the communication wire 1 as a whole. The outer sheath layer 9 contains no magnetic material except for inevitable impurities. The outer sheath layer 9 plays a role of physically protecting the magnetic sheath layer 8 and the constituent members further inside from contact with external objects.

The outer sheath layer 9 preferably contains an organic polymer. Specific examples of organic polymers include olefin polymers such as polyolefins and olefin copolymers, halogen polymers such as polyvinyl chloride, and various engineering plastics, similar to the organic polymers forming the insulating layer 3 and the magnetic sheath layer 8. , elastomers, rubbers, and the like. Among them, it is preferable to use an olefin-based polymer, particularly TPO, because of its excellent insulating properties and heat resistance. The organic polymers may be used singly or in combination of two or more by mixing, laminating, or the like. The organic polymer may be crosslinked or foamed. Preferably, from the viewpoint of enhancing the adhesiveness between the magnetic sheath layer 8 and the outer sheath layer 9, the same organic polymer as at least a part of the organic polymers constituting the magnetic sheath layer 8 is also used in the outer sheath layer 9. should be included. In particular, the outer sheath layer 9 may also contain the same type of elastomer as that contained in the magnetic sheath layer 8 .

Although the thickness of the outer sheath layer 9 is not particularly limited, it is preferably 0.1 mm or more from the viewpoint of enhancing the protective performance for the magnetic sheath layer 8. On the other hand, the thickness of the outer sheath layer 9 is preferably set to 0.5 mm or less from the viewpoint of facilitating enhancement of flexibility.

An example is shown below. However, the present invention is not limited to these examples. In the present examples, unless otherwise specified, the evaluation of each property was performed at room temperature in the air.

[1] Relationship Between Configuration and Characteristics of Magnetic Sheath Layer First, the relationship between the configuration of the magnetic sheath layer and the characteristics of the communication wire was verified.

[Preparation of sample]
An insulating layer was formed by extrusion molding on the outer periphery of a conductor configured as a copper alloy stranded wire to form a core wire. As a constituent material of the insulating layer, a mixture of each component indicated as "insulating layer" in Table 1 below was used. The cross-sectional area of the conductor was 0.18 mm ² and the thickness of the insulating layer was 0.54 mm.

A copper foil was arranged vertically as a metal foil on the outer circumference of the core wire. Furthermore, a braided layer was formed on the outer circumference of the copper foil. The braid layer was constructed as a single braid made of tin-plated annealed copper wire (TA wire).

A magnetic sheath layer was formed on the outer circumference of the braided layer by extrusion molding. As the composition constituting the magnetic sheath layer, a mixture of the organic polymer and the magnetic material powder shown in Table 2 below was used in each of the samples A1 to A11. As shown in Table 2, the thickness of the magnetic sheath layer was 0.3 mm or 0.15 mm.

Furthermore, for each sample, an outer sheath layer was formed on the outer periphery of the magnetic sheath layer by extrusion molding to complete a communication wire. The thickness of the outer sheath layer was 0.2 mm. As a constituent material of the outer sheath layer, a mixture of each component indicated as "outer sheath layer" in Table 1 below was used for each sample. The outer diameters of the obtained communication wires were 3.2 mm and 2.9 mm when the thickness of the magnetic sheath layer was 0.3 mm and 0.15 mm, respectively.

The following components were used for the components constituting the insulating layer, the magnetic sheath layer, and the outer sheath layer. Among the organic polymers, those used for the magnetic sheath layer are also shown together with the density and MFR (value at 230° C., load of 2.16 kg).
(organic polymer)
・TPO1: TPO “Adflex Q200F” manufactured by Lyondell Basell, density: 0.88 g/cm ³ , MFR: 0.8 g/10 min ・TPO2: TPO “Santoprene 203-40” manufactured by Exxon-Mobil
・ PP1: Block PP “Novatec EC9GD” manufactured by Japan Polypropylene Corporation
・ PP2: Homo PP “Novatec EA9FTD” manufactured by Japan Polypro Co., Ltd.
・ PP3: Block PP “Novatec BC06C” manufactured by Japan Polypropylene Corporation, density: 0.91 g / cm ³ , MFR: 60 g / 10 minutes ・ Acid-modified SEBS: “Tuftec M1913” manufactured by Asahi Kasei Corporation
・EEA: "NUC 6940" manufactured by ENEOS NUC, density: 0.95 g/cm ³ , MFR: 20 g/10 minutes (magnetic material)
・Ni—Zn ferrite: “KNI-109” manufactured by JFE Chemical, density: 5.15 g/cm ³
(Other additives)
・Copper damage inhibitor: “CDA-1” manufactured by ADEKA
- Hindered phenol-based antioxidant: BASF "Irganox 1010"
・ Sulfur-based antioxidant: “Antage MB” (2-mercaptobenzimidazole) manufactured by Kawaguchi Chemical Co., Ltd.
・Zinc oxide: “Zinc white 2” manufactured by Hakusui Tech Co., Ltd.
・Flame retardant: “Kisuma 5” (magnesium hydroxide) manufactured by Kyowa Chemical Industry Co., Ltd.

Table 1 shows the component compositions of the materials used to fabricate the insulating layer and the outer sheath layer of all the samples in units of parts by mass.

[Evaluation method]
(1) MFR of composition constituting magnetic sheath layer
The MFR of the composition used to form the magnetic sheath layer of each of Samples A1 to A11 was measured. The measurement was performed in accordance with JIS K 7210 under conditions of 230° C. and a load of 2.16 kg.

(2) Presence or Absence of Holes in Magnetic Sheath Layer After forming the magnetic sheath layer, a spark test was performed by applying a voltage of 3 kV in-line to measure the presence or absence of holes in the surface of the sample by conduction with the braided wire. The magnetic sheath layer was classified into cases where holes were not formed (A) and cases where holes were formed (B).

(3) Noise Shielding Performance Noise shielding performance was evaluated for the communication wires of Samples A1 to A11. As an evaluation, a radiated emission evaluation based on CISPR25 was performed. Specifically, in the anechoic chamber, a horn antenna was installed at a position laterally separated by 1.0 m from the central portion of the communication wire cut to 1500 mm. Then, an electrical signal with a frequency of 1.6 GHz was input to the communication wire, and the amount of noise radiation at this time was measured by a horn antenna. When the noise radiation amount was less than 10 dB (μV/m) (Level 5), the noise shielding property was evaluated as very high (A+). When the noise radiation amount was 10 dB (μV/m) or more and less than 16 dB (μV/m) (Level 4), the noise shielding property was evaluated as high (A). When the noise radiation amount was 16 dB (μV/m) or more and less than 22 dB (μV/m) (Level 3), the noise shielding property was evaluated as low (B). When the noise radiation amount was 22 dB (μV/m) or more (Level 2), the noise shielding property was evaluated as very low (B-).

(4) Mass of Magnetic Sheath Layer After forming the magnetic sheath layer, each sample in the stage before forming the outer sheath layer was cut into a length of 1 m. Then, each member inside the magnetic sheath layer was removed, leaving only the magnetic sheath layer. The mass of the obtained magnetic sheath layer was measured.

(5) Low-temperature impact resistance After cooling the communication wire of each sample by leaving it in a low-temperature bath at -15 ° C for 4 hours, a 100 g hammer was dropped from a height of 100 mm on the communication wire to give an impact. An applied low temperature impact test was performed. After the impact was applied, a voltage of 3 kV was applied to the communication wires while they were immersed in salt water. Those in which the magnetic sheath layer did not break were evaluated as having high low-temperature impact resistance (A), and those in which the magnetic sheath layer fractured were evaluated as having low low-temperature impact resistance (B).

[Evaluation results]
In Table 2, for each of Samples A1 to A11 having different composition ratios and thicknesses of the magnetic sheath layer, the composition (unit: parts by mass) and thickness of the magnetic sheath layer are shown in the upper row, and the results of each evaluation are shown. Shown below.

In samples A1 to A4, the thickness of the magnetic sheath layer is 0.3 mm. None of these samples had holes formed in the magnetic sheath layer (A). The noise shielding property is improved as the content of the magnetic material increases from sample A1 to sample A4.

In sample A5, the same material as sample A4 is used to form a thin magnetic sheath layer with a thickness of 0.15 mm. In sample A4, no holes were formed in the magnetic sheath layer (A), and very high noise shielding properties (A+) were obtained, whereas in sample A5, holes were formed in the magnetic sheath layer (B). , the noise shielding performance is very low (B-). By forming the magnetic sheath layer thin, holes are formed in the magnetic sheath layer during extrusion molding, and electromagnetic waves are transmitted through the holes, which is thought to reduce noise shielding.

When the thickness of the magnetic sheath layer is 0.15 mm, the MFR of the material as a whole is increased by decreasing the TPO content and increasing the PP content from sample A5 to sample A11. there is Samples A7 to A11 with an MFR exceeding 11 g/10 minutes no longer form holes in the magnetic sheath layer (A), and very high noise shielding properties (A+) are obtained. From this, by increasing the MFR of the composition constituting the magnetic sheath layer, the extrusion moldability is improved, and even when the magnetic sheath layer is formed thin, holes are not formed in the magnetic sheath layer. It can be seen that a magnetic sheath layer exhibiting noise shielding performance can be obtained.

In addition, in the samples A1 to A4 in which the thickness of the magnetic sheath layer is 0.3 mm, the mass of the magnetic sheath layer already increases from the region where the content of the magnetic material per 100 parts by mass of the organic polymer component is as low as 150 parts by mass. In contrast, in samples A5 to A11, although the magnetic material content was as high as 750 parts by mass, the magnetic sheath layer was formed as thin as 0.15 mm. As a result, the mass of the magnetic sheath layer is suppressed to 4 g/m or less. In this way, by using a material with a high MFR as the composition that constitutes the magnetic sheath layer, it is possible to form a magnetic sheath layer that is free from defects such as holes and has a small thickness, and that provides excellent noise shielding in communication wires. It is possible to achieve both flexibility and lightness.

As described above, samples A7 to A11 all have very high noise shielding properties (A+). Focusing on low-temperature impact resistance, samples A7 to A9 have high low-temperature impact resistance. (A), the samples A10 and A11 having an MFR exceeding 30 g/10 min have low low-temperature resistance (B). From this, it can be said that it is preferable to prevent the MFR from becoming too high when low-temperature impact resistance is required, such as when a communication wire is used in a low-temperature environment.

[2] Relationship between the thickness of the magnetic sheath layer, the content of the magnetic material, and the noise shielding property Next, the relationship between the thickness of the magnetic sheath layer, the content of the magnetic material, and the noise shielding property was verified.

[Preparation of sample]
In the same manner as in test [1] above, communication wires for samples B1 to B8 were produced. Table 3 shows the composition constituting the magnetic sheath layer and the thickness of the magnetic sheath layer. The organic polymer component constituting the magnetic sheath layer was the same as that of sample A8 of test [1], and the magnetic material content was varied between samples B1 to B8. The thickness of the magnetic sheath layer is set so that the mass of the magnetic sheath layer per unit length is 3 g/m. Specifically, assuming that there is no volume change due to mixing of the components, the density of the magnetic sheath layer is calculated as shown in the table based on the density of each constituent component of the magnetic sheath layer. Second, the thickness of the magnetic sheath layer was set so that the mass was 3 g/m. No holes were formed in the surface of the magnetic sheath layer in any of the samples produced.

Furthermore, using the same composition as samples B4 and B8, communication wires formed with magnetic sheath layers having different thicknesses were produced as samples B4a, B4b, and samples B8a, B8b. The thickness of the magnetic sheath layer was 0.12 mm, 0.14 mm, and 0.16 mm for all compositions.

[Evaluation method]
The noise shielding properties of the communication wires of each sample were evaluated by radiated emission evaluation in the same manner as in test [1] above. Then, the noise radiation amount and the evaluation classification based on the same criteria as in test [1] were recorded.

[Evaluation results]
Table 3 below shows the component compositions and thicknesses of the magnetic sheath layers of samples B1 to B8, and evaluation results of noise shielding properties.

According to Table 3, samples B4 to B8, in which the content of the magnetic material in the composition constituting the magnetic sheath layer is 350 parts by mass or more and 850 parts by mass or less, have a mass per unit length of 3 g/m. The thickness of the magnetic sheath layer, which is defined as the thickness of the magnetic sheath layer, is in the range of 0.12 mm or more and 0.16 mm or less. Sufficiently high noise shielding properties were obtained for all of the samples B4 to B8 (A or A+). On the other hand, samples B1 to B3, in which the thickness of the magnetic sheath layer exceeds 0.16 mm but the content of the magnetic material is less than 350 parts by mass, do not provide sufficient noise shielding properties (B or B -).

Furthermore, Table 4 below shows the component composition and thickness of the magnetic sheath layers in samples B4, B4a, B4b and samples B8, B8a, B8b, and evaluation results of noise shielding properties.

According to Table 4, if the composition of the magnetic sheath layer is the same, the noise radiation amount is almost the same even if the thickness of the magnetic sheath layer is different. From this, it is confirmed that the noise shielding performance of the magnetic sheath layer does not substantially depend on the thickness of the magnetic sheath layer in the range of 0.12 to 0.16 mm, and is mainly determined by the concentration of the magnetic material. be done. In addition, although the magnetic material concentration of 850 parts by mass of sample B8 is the highest among those shown in Table 3 above, even with the magnetic sheath material containing the magnetic material at the maximum concentration, sample B8 , it can be seen that even a thin layer region with a thickness of 0.12 mm has a very high noise shielding property (A+), and a magnetic sheath layer without holes can be formed. That is, from the results of Table 4, the density of the magnetic material in the magnetic sheath material is set to be in the range of 350 parts by mass to 850 parts by mass with respect to 100 parts by mass of the organic polymer component, and the thickness is 0.12 mm to 0.16 mm. If the magnetic sheath layer is formed, high noise shielding properties can be obtained by satisfying both requirements of containing a sufficient concentration of magnetic material and forming a magnetic sheath layer without holes.

As described above, in the magnetic sheath layer, the content of the magnetic material is 350 parts by mass or more and 850 parts by mass or less with respect to 100 parts by mass of the organic polymer component, and the thickness of the magnetic sheath layer is 0.12 mm or more and 0.16 mm or less. Then, a sufficiently high noise shielding property can be secured. By selecting the content of the magnetic material and the thickness of the magnetic sheath layer within these ranges, the weight of the magnetic sheath layer can be reduced to a mass of 3 g/m or less.

[3] Relationship between thickness of magnetic sheath layer and MFR Finally, the relationship between the thickness of the magnetic sheath layer and the MFR of the composition forming the magnetic sheath layer was verified.

[Preparation of sample]
In the same manner as in Test [1] above, communication wires of Samples C1 to C17 were produced. At this time, the component compositions of the constituent materials of the magnetic sheath layer were as shown in Tables 5 and 6 below. As shown in Tables 5 and 6, the thickness of the magnetic sheath layer was 0.16 mm or 0.12 mm.

[Evaluation method]
The MFR of the composition constituting the magnetic sheath layer, the presence or absence of holes in the magnetic sheath layer, and the low-temperature impact resistance were evaluated in the same manner as in test [1] above.

[Evaluation results]
Tables 5 and 6 below show the component composition and thickness of the magnetic sheath layer and the results of each evaluation for samples C1 to C17.

According to Tables 5 and 6, regardless of whether the thickness of the magnetic sheath layer is 0.16 mm or 0.12 mm, the MFR of the composition constituting the magnetic sheath layer is 11.8 g/10 min or more. For example (Samples C5 to C8, C12 to C17), holes were not formed in the magnetic sheath layer (A). From this result, it can be seen that if a composition having an MFR of 11.8 g/10 min or more is used as the composition constituting the magnetic sheath layer, a large amount of magnetic material of 850 parts by mass is added to 100 parts by mass of the organic polymer component. It can be seen that the formation of holes can be avoided in the magnetic sheath layer formed as thin as 0.12 mm even in the case of 0.12 mm. Furthermore, if the MFR of the composition constituting the magnetic sheath layer is 23.9 g/10 minutes or less (Samples C1 to C6, C9 to C14), the low temperature impact resistance can be increased (A).

Although the embodiments of the present disclosure have been described in detail above, the present invention is by no means limited to the above embodiments, and various modifications are possible without departing from the gist of the present invention.

1 Communication Wire 2 Conductor 3 Insulation Layer 4 Core Wire 5 Metal Foil 6 Braided Layer 7 Metal Shield Layer 8 Magnetic Sheath Layer 9 Outer Sheath Layer

Claims

a conductor;
an insulating layer covering the outer periphery of the conductor;
a magnetic sheath layer covering the outside of the insulating layer,
The magnetic sheath layer contains an organic polymer and a powdered magnetic material,
The content of the magnetic material in the magnetic sheath layer is 350 parts by mass or more and 850 parts by mass or less with respect to 100 parts by mass of the organic polymer,
A communication wire, wherein the composition constituting the magnetic sheath layer has a melt flow rate of 11.8 g/10 minutes or more measured at 230° C. under a load of 2.16 kg.
The communication wire according to claim 1, wherein the composition constituting the magnetic sheath layer has a melt flow rate of 23.9 g/10 minutes or less measured at 230°C under a load of 2.16 kg.
The electric wire for communication according to claim 1 or 2, wherein the magnetic sheath layer has a thickness of 0.12 mm or more and 0.16 mm or less.
The electric wire for communication according to any one of claims 1 to 3, wherein the mass per unit length of the magnetic sheath layer is 3 g/m or less.
The communication wire is configured as a coaxial wire having a metal shield layer on the outer periphery of the insulating layer,
The electric wire for communication according to any one of claims 1 to 4, wherein the magnetic sheath layer is provided on the outer circumference of the metal shield layer.