JP2005310664A - Electric wire and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electric wire whose covering layers can be easily peeled on the terminal treatment, and provide its manufacturing method. <P>SOLUTION: The electric wire has a conductor 10, and a first covering layer and a second covering layer which are disposed outside the conductor adjacently to each other, and are composed of crosslinkable materials. For example, let the first covering layer be an insulation layer 30, and let the second covering layer be an outer semiconductor layer 40. The crosslinking degrees of the first and second covering layers are different. By making the crosslinking degrees of the first and second covering layers different and changing the hardnesses of the layers, the interlayer peelability on the terminal treatment is improved, and the workability of the terminal treatment is improved. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an electric wire and a manufacturing method thereof. In particular, the present invention relates to an electric wire capable of easily peeling a semiconductive layer and an insulating layer during terminal processing and a method for manufacturing the electric wire.

  Conventionally, the wire shown in FIG. 3 is known as an electric wire for an automobile wire harness. This includes a conductor 10, an insulating layer 30, a shield layer 50, and a sheath 60 in order from the center side (see, for example, Patent Document 1). Such electric wires are used not only for automobiles using ordinary internal combustion engines but also for electric cars and hybrid cars.

  In particular, electric wires used in electric vehicles and hybrid vehicles are required to have higher pressure resistance. For example, it is conceivable to provide a semiconductive layer on at least one of the inside and the outside of the insulating layer as a measure for suppressing the partial discharge accompanying the increase in the voltage.

  From the viewpoint of suppressing partial discharge, this semiconductive layer needs to be in close contact with the insulating layer without any voids. It is preferable that it can be easily peeled from the insulating layer.

  A semiconductive layer in a general power cable or the like is extrusion-coated with an insulating layer, and a method of cross-linking the insulating layer and the semiconductive layer in one cross-linking step is employed.

JP-A-6-124608 (Fig. 17)

  However, although the semiconductive layer forming technique described above provides high adhesion between the insulating layer and the semiconductive layer, there is a problem that it is difficult to peel the semiconductive layer from the insulating layer during terminal processing.

  When the insulating layer and the semiconductive layer are coextruded and both layers are cross-linked in a single cross-linking step, both the layers are also cross-linked, so that the adhesion is increased and the layers cannot be easily separated during the terminal treatment. .

  Accordingly, a main object of the present invention is to provide an electric wire that can easily peel off each coating layer during terminal processing.

  Another object of the present invention is to provide a method of manufacturing an electric wire that can easily peel off each coating layer during terminal processing.

  The present invention achieves the above object by varying the degree of cross-linking of the two layers to be peeled off during terminal processing.

  That is, the electric wire of the present invention is an electric wire having a conductor, a first coating layer and a second coating layer which are arranged adjacent to each other outside the conductor and are formed of a crosslinkable material. The degree of cross-linking between the coating layer and the second coating layer is different.

  This electric wire typically includes a conductor, an internal semiconductive layer, an insulating layer, an external semiconductive layer, a shield layer, and a sheath in order from the center toward the outer peripheral side. Of these, either the internal semiconductive layer or the external semiconductive layer may be omitted. For example, the insulating layer is a first coating layer, and the external semiconductive layer is a second coating layer.

  The conductor of the electric wire of the present invention is not particularly limited as long as the necessary power transmission capacity can be secured, and the material and configuration are not particularly limited. Examples of the material include copper wire, tin-plated copper wire, aluminum wire, aluminum alloy wire, steel core aluminum wire, copper fly wire, nickel-plated copper wire, silver-plated copper wire, and copper-covered aluminum wire. As the configuration of the conductor, a single wire and a stranded wire are conceivable, but generally a stranded wire structure in which a plurality of strands are combined is preferable.

  The insulating layer is configured to have voltage resistance according to the voltage of the electric wire. The insulating layer is made of a crosslinkable material. For example, polyethylene, polypropylene, and polyvinyl chloride are suitable. This insulating layer may be formed by extrusion.

  The semiconductive layer, that is, the internal semiconductive layer and the external semiconductive layer are preferably composed of a mixture of a base resin and a conductive filler. Predetermined conductivity can be imparted to the semiconductive layer by mixing conductive fillers. The base resin is preferably a crosslinkable material such as polyethylene, polypropylene, polyvinyl chloride and the like. Carbon black can be suitably used as the filler.

  When the base resin of the insulating layer or semiconductive layer is polyethylene, examples of the crosslinking agent include dicumyl peroxide, 1,3-bis (tertiarybutylperoxyisopropyl) benzene (P-14), 2,5-dimethyl. -2,5-di (tertiarybutylperoxy) hexyne-3 (Kayahexa YD) and the like. These crosslinking agents may be used as one kind or a mixture of two or more kinds. The amount of the crosslinking agent is appropriately determined according to the purpose of use of the obtained insulator, and is not particularly limited. A preferred blending amount is about 1.5 to 2.5 parts by weight per 100 parts by weight of polyethylene.

  Examples of the crosslinking aid in this case include triallyl isocyanurate, N, N′-metaphenylene dimaleimide, triallyl cyanate, diallyl phthalate, and the like. These can be used as one kind or a mixture of two or more kinds. The amount of the crosslinking aid is preferably about 0.2 to 3.0 parts by weight with respect to 100 parts by weight of polyethylene.

  When the base resin is polypropylene, the cross-linking agent is preferably t-butylcumyl peroxide, 2,5 dimethyl-2,5 di (t-butylperoxy) hexyne-3, for example. These crosslinking agents may be used as one kind or a mixture of two or more kinds. The amount of the crosslinking agent is preferably 0.2 to 5 parts by weight with respect to the total amount of polypropylene.

  As the crosslinking aid in this case, quinone dioxime, triallyl trimellylate, trimethylolpropane trimethacrylate, trimethylolpropane triacrylate, ethylene glycol dimethacrylate, and the like can be used. The addition ratio of these crosslinking aids is preferably about 0.2 to 5 parts by weight with respect to 100 parts by weight of the total amount of the resin components.

  When the base resin is polyvinyl chloride, an isocyanate compound can be used as the crosslinking agent. Examples of the isocyanate compound include compounds mainly composed of an isocyanate monomer and polyisocyanate.

  In this case, the crosslinking assistant can be a compound mainly composed of a metal salt. Specific examples include metal salts such as lauric acid, stearic acid, naphthenic acid, ricinoleic acid, octylic acid, barium, calcium, magnesium, strontium, lead, tin, cadmium, and zinc.

  In addition, antioxidants, pigments, UV stabilizers, fillers, plasticizers, lubricants, and the like can be appropriately added to the coating material for the electric wire of the present invention.

  This semiconductive layer may be formed by extrusion independently of the insulating layer. If each semiconductive layer is formed by extrusion, unlike the case where the conductive cloth tape is used, there is no irregular portion such as an end portion or an edge of the conductive cloth tape, and the origin of the water tree can be eliminated. .

  In addition, in the electric wire of the present invention, a shield layer is usually formed on the outer semiconductive layer, and a sheath is further provided on the shield layer. It is desirable to use a braided material of metal wire such as copper wire for the shield layer. By providing the shield layer, guidance prevention shielding and danger prevention shielding can be performed. The sheath is generally made of chloroprene rubber, vinyl resin, polyethylene or the like. By providing the sheath, the insulating layer (shield layer) can be mechanically protected.

  The electric wire of the present invention is preferably used as a wire harness wire used for wiring for automobiles. In particular, it is most suitable to be used as an electric wire for a wire harness for an electric vehicle or a hybrid vehicle that is required to have high voltage resistance recently. In particular, it can be expected to be used as an electric wire having a withstand voltage characteristic of 600 V or higher, more preferably 800 V or higher, and further preferably 1 kV or higher.

  On the other hand, the electric wire manufacturing method of the present invention is an electric wire manufacturing method in which a first coating layer and a second coating layer made of a crosslinkable material are formed adjacent to each other. In such a production method, the degree of crosslinking between the first coating layer and the second coating layer is made different by adopting different methods depending on the crosslinking method.

  In order to vary the degree of crosslinking in each coating layer, when the crosslinking method is a radiation crosslinking method, by changing the radiation dose, when the crosslinking method is a chemical crosslinking method, the type and content of the crosslinking agent, the crosslinking aid This can be realized by varying one or more of the types and contents. Of course, the degree of cross-linking of both coating layers may be varied by using both of these methods in combination. In the case of the chemical crosslinking method, various crosslinking methods such as vapor crosslinking, heat ray crosslinking, and water crosslinking can be used.

  First, in the case of the radiation cross-linking method, the irradiation amount of radiation, for example, electron beam or γ-ray, is changed between the first coating layer and the second coating layer. When this radiation crosslinking method is performed, the first coating layer and the second coating layer may be formed by extrusion independently, and radiation may be irradiated for each extrusion. For example, when an external semiconductive layer is formed on an insulating layer, an insulating layer is first formed by extrusion, and this insulating layer is irradiated with radiation to be crosslinked, and the external semiconductive layer is formed by extrusion on the crosslinked insulating layer. Then, the external semiconductive layer is further irradiated with radiation to be crosslinked. At this time, the degree of crosslinking between the two layers may be changed by changing the radiation dose between the insulating layer and the external semiconductive layer.

  Next, in the case of the chemical crosslinking method, since various types of crosslinking agents and crosslinking aids are used depending on the coating material to be crosslinked, at least one of various crosslinking agents, types of crosslinking aids, and content is selected. What is necessary is just to adjust and to change the crosslinking degree of each coating layer.

  According to the electric wire of the present invention, the hardness of each layer is changed by changing the degree of crosslinking between the first coating layer and the second coating layer, and the delamination property at the time of terminal processing is improved, thereby improving the workability of the terminal processing. can do.

  In the electric wire of the present invention, if the first covering layer is an insulating layer and the second covering layer is an external semiconductive layer, the external semiconductive layer can be easily peeled from the insulating layer during terminal processing.

  According to the electric wire of the present invention, by providing a semiconductive layer, it is possible to obtain a semiconductive layer having excellent high voltage resistance and high delamination properties, and can be suitably used as a wire harness electric wire.

  According to the method for producing an electric wire of the present invention, when the first coating layer and the second coating layer are cross-linked by a radiation cross-linking method, the cross-linking degree of both layers can be easily changed, and an electric wire excellent in delamination property can be obtained. Can be obtained.

  According to the method for producing an electric wire of the present invention, when the first coating layer and the second coating layer are cross-linked by a chemical cross-linking method, the cross-linking degree of both layers can be easily changed, and an electric wire having excellent delamination property can be obtained. Can be obtained.

  According to the method for producing an electric wire of the present invention, when the first coating layer and the second coating layer are cross-linked using a radiation cross-linking method and a chemical cross-linking method, the degree of cross-linking of both layers can be easily varied, An electric wire excellent in delamination property can be obtained.

  Embodiments of the present invention will be described below.

(First embodiment)
FIG. 1 is a cross-sectional view of the electric wire of the present invention. The electric wire includes a conductor 10, an inner semiconductive layer 20, an insulating layer 30, an outer semiconductive layer 40, a shield layer 50, and a sheath 60 in this order from the center.

  Here, 19 strands of 0.32 mm diameter annealed copper wire were combined to form a twisted strand, and further, 19 strands were combined to form a conductor 10 having a nominal cross-sectional area of 30 sq.

  An internal semiconductive layer 20 is formed immediately above the conductor 10. The inner semiconductive layer 20 was formed by coextrusion with the insulating layer described below. As the material of the inner semiconductive layer 20, a mixture of a soft polyethylene base resin and acetylene black as a conductive filler was used.

  An insulating layer 30 is formed on the inner semiconductive layer 20. For this insulating layer, a resin composition using polyethylene as a base resin and dicumyl peroxide as a crosslinking agent was used. As shown in FIG. 2, after the insulating layer is extruded, the insulating layer is crosslinked by heating.

  Subsequently, an external semiconductive layer 40 is formed on the crosslinked insulating layer 30. The outer semiconductive layer 40 is formed by extrusion independent of the insulating layer. Also for the outer semiconductive layer, a resin composition in which a soft polyethylene base resin was mixed with acetylene black, which is a conductive filler, and dicumyl peroxide was added as a crosslinking agent were used. The amount of the crosslinking agent was different from the amount of the crosslinking agent in the insulating layer. The extruded outer semiconductive layer is also heated to crosslink.

  A shield layer 50 is formed on the cross-linked outer semiconductive layer 40. As the shield layer 50, a braided material made of a tin-plated copper wire having a diameter of 0.3 mm was used.

  Then, a sheath 60 is formed on the shield layer 50. Here, the sheath 60 was formed by extruding polyvinyl chloride to a thickness of 1.0 mm.

  For comparison, a comparative electric wire having the same cross-linking degree with the same content of the cross-linking agent in the insulating layer and the outer semiconductive layer is also prepared, and the external semiconductive layer is easily peeled from the insulating layer in the electric wire of the present invention and the comparative electric wire. Sex was compared. As a result, it was confirmed that the electric wire of the present invention can easily peel the external semiconductive layer as compared with the comparative electric wire.

(Second embodiment)
Next, the electric wire of the present invention in which the degree of crosslinking between the insulating layer and the external semiconductive layer is made different by performing electron beam crosslinking will be described.

  Also in this case, the configuration of the electric wire is as shown in FIG. Therefore, the difference from the first embodiment will be mainly described here. In this embodiment, the insulating layer and the external semiconductive layer in FIG. 2 are cross-linked by electron beam irradiation. At that time, the electron beam irradiation amount is changed between the insulating layer and the external semiconductive layer.

  For comparison, a comparison electric wire with the same electron beam irradiation amount of the insulating layer and the outer semiconductive layer and the same degree of crosslinking was also produced, and the external semiconductive layer was easily peeled from the insulating layer in the electric wire of the present invention and the comparative electric wire. Sex was compared. As a result, it was confirmed that the electric wire of the present invention can easily peel the external semiconductive layer as compared with the comparative electric wire.

  The electric wire of the present invention can be used for various electric wires. It can be used for a wire harness of an electric vehicle or a hybrid vehicle as well as a conventional vehicle having an internal combustion engine. Moreover, it is anticipated that the manufacturing method of this invention electric wire will be utilized in the said electric wire manufacturing field.

It is a cross-sectional view of the electric wire of the present invention. It is process drawing which shows a part of manufacturing method of this invention electric wire. It is sectional drawing of the electric wire for conventional wire harnesses.

Explanation of symbols

10 conductor
20 Internal semiconductive layer
30 Insulation layer
40 External semiconductive layer
50 Shield layer
60 sheath

Claims (6)

An electric wire having a conductor and a first coating layer and a second coating layer formed of a crosslinkable material arranged adjacent to each other outside the conductor;
The electric wire, wherein the first coating layer and the second coating layer have different degrees of crosslinking.   The electric wire according to claim 1, wherein the first covering layer is an insulating layer, and the second covering layer is an external semiconductive layer.   The electric wire according to claim 1, wherein the electric wire is a wire harness electric wire. A method of manufacturing an electric wire, wherein a first coating layer and a second coating layer made of a crosslinkable material are formed adjacent to each other outside the conductor,
Forming the first coating layer and the second coating layer by independent extrusion processes,
A wire cross-linking step is performed for each extrusion step, and the degree of cross-linking of both coating layers is varied by making the radiation dose of the first coating layer different from the radiation dose of the second coating layer. Manufacturing method. A method of manufacturing an electric wire, wherein a first coating layer and a second coating layer made of a crosslinkable material are formed adjacent to each other outside the conductor,
It is characterized in that the degree of cross-linking of both coating layers is made different by changing one or more of the type and content of the crosslinking agent and the type and content of the crosslinking aid contained in the first coating layer and the second coating layer. A method for manufacturing an electric wire. A method of manufacturing an electric wire, wherein a first coating layer and a second coating layer made of a crosslinkable material are formed adjacent to each other outside the conductor,
A method for producing an electric wire, characterized in that the following means (A) and (B) are used in combination in order to make the degree of cross-linking of both coating layers different.
(A) The first coating layer and the second coating layer are formed by independent extrusion processes, and the radiation crosslinking process is performed for each extrusion process. The radiation dosage of the first coating layer and the radiation dosage of the second coating layer And different.
(B) One or more of the types and contents of the crosslinking agents and the types and contents of the crosslinking aids contained in the first coating layer and the second coating layer are varied.

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