JP2008041568A - Straight angle electric wire having semiconductive layer, and manufacturing method therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a straight angle electric wire having a thinned semiconductive layer of excellent high-frequency characteristic. <P>SOLUTION: This straight angle electric wire 10 of the present invention has a conductor 1 with a straight angle cross section, and the semiconductive layer 2 formed in an outer circumference thereof, and a relation A≥0.6×B is satisfied in the semiconductive layer 2, where A represents a film thickness of a corner part 3 and B represents a film thickness of a flat part 4. The film thickness B is preferably 130μm or less, and a volume resistivity of the semiconductive layer is preferably 10<SP>2</SP>-10<SP>10</SP>Ωcm. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a rectangular electric wire having a semiconductive layer and a method for manufacturing the same, and more particularly to a flat electric wire having excellent high frequency characteristics and having a thinned semiconductive layer and a method for manufacturing the same.

  Conventionally, an enameled wire having an insulating layer provided on a conductor has been used for the purpose of electrical insulation. In recent years, electric devices, industrial motors, and the like tend to be used by inverter control at high voltage in accordance with demands for energy saving and miniaturization and high performance. However, in electrical equipment that employs inverter control, an excessive surge voltage is generated, causing problems such as degradation of enameled wire due to corona discharge and dielectric breakdown due to discharge. Audio, computer displays, monitor televisions, etc. operate with high-frequency signals. For example, a high-frequency voltage around 100 kHz is often used, and when such a high frequency is applied to an enameled wire, corona discharge occurs. However, the insulating layer of the enamel wire is deteriorated by the local temperature rise and the action of the generated ozone.

In order to solve such problems, as a high-frequency or high-voltage electric wire, a conductor having a round cross section, a semiconductive layer formed by directly applying and baking a semiconductive paint on the outer surface of the conductor, There has been proposed an electric wire having an insulating layer obtained by directly applying and baking an insulating paint on the outer surface of a semiconductive layer (Patent Documents 1 and 2). According to such an electric wire, a round electric wire with excellent high-frequency characteristics and withstand voltage characteristics can be obtained with little decrease in life even when used under a high-frequency voltage. However, in order to meet the demand for lighter and smaller electrical equipment, the conductor with a round cross section is replaced with a conductor with a rectangular cross section, and a semiconductive paint is directly applied and baked on the outer surface to form a semiconductive layer. When it is attempted, it becomes difficult to form a semiconductive layer having a required thickness at the corner portion of the conductor. Therefore, in order to obtain a semiconductive layer having a necessary thickness, it is necessary to repeatedly apply and bake the semiconductive paint, and the production efficiency is remarkably lowered. Furthermore, in the method in which a semiconductive layer is formed by directly applying and baking a semiconductive paint on a conductor, it is difficult to make the semiconductive layer into a thin film, so that the electric device has not been sufficiently reduced in weight and size.
JP 2005-251573 A Japanese Patent Application Laid-Open No. 08-96625

  The present invention has been made in view of such circumstances, and a problem to be solved is to provide a rectangular electric wire having excellent high-frequency characteristics and having a thinned semiconductive layer.

  As a result of intensive studies to solve the above problems, the present inventors formed a semiconductive layer by electrodeposition on the outer periphery of a flat rectangular conductor, and specified the film thickness of the flat portion and the corner portion of the semiconductive layer. The present inventors have found that the above problems can be solved by using a flat electric wire satisfying the relationship, and have completed the present invention.

That is, the present invention is as follows.
(1) A conductor having a rectangular cross section and a semiconductive layer formed on the outer periphery thereof, and the thickness A of the corner portion of the semiconductive layer and the thickness B of the flat portion of the semiconductive layer are A ≧ A flat electric wire having a semiconductive layer that satisfies a relationship of 0.6 × B.
(2) The flat electric wire according to (1), wherein the film thickness B is 30 μm or less.
(3) The rectangular electric wire according to (1) or (2), wherein the semiconductive layer has a volume resistivity of 10 ² to 10 ¹⁰ Ω · cm.
(4) The flat electric wire according to any one of (1) to (3), wherein the semiconductive layer is formed by electrodeposition of a semiconductive paint.
(5) The flat electric wire according to (4), wherein the semiconductive paint is an insulating paint containing a conductive material.
(6) A rectangular electric wire having a semiconductive layer according to (5), wherein the ratio of the conductive material to the total solid content of the semiconductive paint is 35 to 55% by weight.
(7) A method for producing a rectangular electric wire having a semiconductive layer, in which a semiconductive paint is electrodeposited and baked on the outer periphery of a conductor having a rectangular cross section to form a semiconductive layer.
(8) The production method according to (7), wherein an insulating paint containing a conductive material is used as the semiconductive paint.
(9) The production method according to (8), wherein the proportion of the conductive material in the total solid content of the semiconductive paint is 35 to 55% by weight.

  ADVANTAGE OF THE INVENTION According to this invention, the rectangular electric wire which has sufficient film thickness not only in a flat part but in a corner part on the outer periphery of a rectangular conductor, and also has the semiconductive layer thinned can be provided. This makes it possible to prevent deterioration of the electric wire due to corona discharge, dielectric breakdown, and the like, and therefore the flat electric wire of the present invention is useful as a high-frequency electric wire and a dielectric breakdown-resistant electric wire.

  Hereinafter, the present invention will be described in detail with reference to preferred embodiments thereof. In the description of the drawings, the same elements are denoted by the same reference numerals, and redundant description is omitted. For the convenience of illustration, the dimensional ratios in the drawings do not necessarily match those described. The present invention is not limited to the form shown in the drawings.

(Square wire with semiconductive layer)
FIG. 1 is a cross-sectional view showing an embodiment of a flat electric wire having a semiconductive layer of the present invention. A flat electric wire 10 according to the present embodiment includes a conductor 1 having a flat cross section and a semiconductive layer 2 formed on the outer periphery thereof. The semiconductive layer 2 has a corner portion 3 constituting four corners and a flat portion 4 constituting four sides, and the film thickness A of the corner portion 3 and the film thickness B of the flat portion 4 are expressed by the following formula (I ) Is satisfied.
A ≧ 0.6 × B (I)
On the other hand, from the viewpoint of the stability of the film characteristics, the film thickness A is preferably close to the film thickness B (A = B), but when viewed from the characteristics required for a general coil, the above formula (I) Is sufficient.

  Here, the film thickness A of the corner portion 3 means the shortest distance from the intersection 5 of the two sides constituting the conductor 1 to the surface of the semiconductive layer 6 as shown in FIG. Further, the film thickness B of the flat portion 4 refers to the shortest distance from one side 7 constituting the conductor 1 to the semiconductive layer surface 6. Further, the film thickness B is preferably 30 μm or less, more preferably 1.5 to 10 μm, and further preferably 8 to 10 μm from the viewpoint of the resistance to trauma. If it is in the said range, the electrical property of the semiconductive layer 2 can be sufficiently secured, and the cable size can be reduced (smaller diameter).

Furthermore, the volume resistivity of the semiconductive layer 2 is preferably 10 ² to 10 ¹⁰ Ω · cm, more preferably 10 ² to 10 ⁶ Ω · cm. If the volume resistivity is within the above range, there is an advantage that the influence of the eddy current between the conductors can be largely canceled. In general, the lower the volume resistivity, the better. In the present invention, in order to measure the volume resistivity of the semiconductive layer 2, a metal foil (not shown) having a width L is wound around the outer periphery of the flat electric wire 10, and a resistance value R between the conductor 1 and the metal foil is measured. Is actually measured. The volume resistivity ρ (Ω · cm) of the semiconductor layer 2 is calculated as (2 × π × L × R) ÷ (L _N (D / d), where L _N (D / d) is ( D / d) is a natural logarithm, D is the diameter of a circle having the same area as the cross-sectional area of the flat wire 10, and d is the diameter of a circle having the same area as the cross-sectional area of the conductor 1.

As the material for the flat rectangular conductor, a highly conductive metal is preferably used, and specifically, copper, aluminum, copper alloy, copper clad aluminum, nickel-plated copper and the like can be mentioned.
The dimensions of the flat rectangular conductor can be appropriately selected, but usually the thickness is 500 μm or less (preferably 10 to 200 μm) and the width is 0.1 to 10 mm (preferably 0.1 to 5 mm). The aspect ratio is 1: 3 to 1: 100 (preferably 1: 5 to 1:30).

The semiconductive layer is suitably formed by electrodeposition of a semiconductive paint, but any semiconductive paint can be used without particular limitation as long as it exhibits semiconductivity. As the semiconductive paint, for example, a kneaded conductive material in an insulating paint is preferably used. Examples of the base insulating paint include acrylic paint, polyvinyl formal, polyurethane, polyester, polyesterimide, polyamideimide, polyimide, and the like, and these are preferably used in the form of a water-dispersed resin varnish. Among these, polyurethane and acrylic paint are preferable. In addition, examples of the conductive material include metal powders such as carbon black and silver, and carbon black is particularly preferable. Such a conductive material preferably accounts for 35 to 55% by weight of the total solid content of the semiconductive paint. If the content is within the above range, it is advantageous in that a uniform film can be formed without impairing the electrodeposition properties of the paint.
The total solid content of the semiconductive paint is a component that does not evaporate when the semiconductive paint is sufficiently dried (at 200 ° C. for 30 minutes), and is contained in at least the conductive material and the insulating paint. Contains resin. The total solid concentration of the semiconductive paint is preferably 15 to 25% by weight, more preferably 18 to 22% by weight.

  As mentioned above, although the flat electric wire which concerns on this invention was demonstrated in detail based on the embodiment, this invention is not limited to the said embodiment. The present invention can be variously modified without departing from the gist thereof. For example, one or more insulating layers having a thickness of about 1.0 to 10 μm may be provided on the semiconductive layer formed on the outer periphery of the rectangular conductor. As a result, it is possible to provide a flat electric wire that is more excellent in high-frequency characteristics, and the flat electric wire thus obtained is useful as an electric coil, a cable, or the like.

(Manufacturing method of a flat electric wire having a semiconductive layer)
FIG. 2 is a schematic cross-sectional view showing an example of a manufacturing process of a flat electric wire having a semiconductive layer of the present invention. The method for producing a rectangular electric wire having a semiconductive layer according to the present invention is characterized in that a semiconductive layer is formed by electrodeposition and baking treatment of a semiconductive paint on the outer periphery of a conductor having a rectangular cross section. Hereinafter, it will be described in detail with reference to FIG.

  First, the flat conductor 1 is prepared. The flat conductor 1 is made of the above-described material, and can be appropriately selected.

  Next, an electrodeposition process is performed to form the semiconductive layer 2 on the flat rectangular conductor 1. The electrodeposition process is performed, for example, in an electrodeposition tank 13 that contains an electrodeposition liquid 11 and is provided with a cylindrical cathode 12 made of a platinum plate. As the electrodeposition liquid 11, an insulating paint containing a conductive material is usually used, and a water-dispersed resin varnish is suitably used as the insulating paint. Specifically, in the electrodeposition process, a rectangular conductor 1 connected to the anode side of a DC power source (not shown) is placed in a cylindrical cathode 12 installed in an electrodeposition tank 13 via a roll 14. To pass through. As a result, the electrodeposition resin layer on the rectangular conductor 1 has a necessary thickness not only in the flat portion but also in the corner portion due to the potential difference between the rectangular conductor 1 serving as the anode and the cathode, and the film thickness can be made as large as possible. Therefore, it becomes possible to make a thin film and coat it.

  At that time, the electrodeposition resin layer is formed so that the film thickness A of the corner portion and the film thickness B of the flat portion satisfy the relationship of the above formula (I). As a means for controlling the film thickness so as to satisfy the relationship of the above formula (I), for example, there is a method of appropriately adjusting the electrodeposition conditions, and as another means, the concentration of the water-dispersed varnish used as the insulating paint It is also possible to adjust.

  In this embodiment, a water dispersion type varnish is used. However, when a solution type varnish is used, the electrodeposition resin layer at the corner portion tends to flow out due to surface tension during baking, and in some cases, the thickness of the corner portion is substantially reduced. May be zero. Therefore, it is preferable to use a water-dispersed varnish, but a solution-type varnish may be used as long as a sufficiently thick film can be formed at the corner. The preferred content of the conductive material is as described above.

  Immediately after the electrodeposition treatment, the electrodeposition resin layer may be dried and baked, but it is preferable to pass through the solvent tank 16 containing the organic solvent 15 before such treatment. As the organic solvent 15, water is dissolved at least about 1% by weight, preferably at least about 10% by weight, and the electrodeposited resin layer is in a semi-cured state before drying and baking on the rectangular conductor 1 or before reaching the state. Those that swell, preferably dissolve are used. Specifically, monovalent or polyvalent alcohols such as methanol, ethanol, propall, ethylene glycol, glycerin; ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol isopropyl ether, ethylene glycol monobutyl ether, ethylene glycol diethyl ether Cellosolves such as ether glycol dibutyl ether and ether glycol monophenyl ether; nitrogen-containing solvents such as N, N-dimethylformamide, N, N-dimethylacetamide and N-methyl-2-pyrrolidone; ion-containing solvents such as dimethyl sulfoxide Is mentioned. Among these, N, N-dimethylformamide, N, N-dimethylacetamide, N-methyl-2-pyrrolidone and dimethyl sulfoxide are preferable. By such solvent treatment, the resin particles in the electrodeposited resin layer can be effectively fused at the time of baking to form a uniform film thickness without pinholes. It should be noted that the same effect can be obtained even when a rectangular electric wire on which an electrodeposited resin layer is formed is allowed to pass through an organic solvent vapor or mist.

  Further, a wiping device such as an air wiper or a roller wiper may be provided at the outlet of the rectangular electric wire in the electrodeposition tank 13 and the solvent tank 16 to remove excess varnish and treatment liquid on the electrodeposition resin layer. In particular, when the electrodeposition treatment is performed at a high speed, unelectrodeposited varnish or the like adhering to the electrodeposited resin layer may foam during the baking process, thereby hindering the high-speed operation. For this reason, if varnish etc. are removed with the above-mentioned wiping method, foaming will be prevented and high-speed operation | work of 50 m / min or more will be attained, for example.

  Next, the electrodeposition resin layer is dried and baked. The drying and baking steps can be performed through a series of heating devices, but can be performed through separate heating devices. In the present embodiment, the latter method is adopted as shown in FIG. The flat conductor 1 is introduced into the drying device 17. Thereby, the rectangular conductor 1 is heated, and the organic solvent and water in the electrodeposition resin layer are removed by evaporation. Although the temperature of the drying apparatus 17 can be suitably selected according to the kind of organic solvent, it is generally about 60-300 degreeC, Preferably it is about 100-250 degreeC. In the drying step, the preceding stage, for example, a high temperature treatment of about 200 to 500 ° C. is applied in order to simultaneously promote the evaporation of the liquid or to perform semi-curing or complete curing of the electrodeposited resin layer on the rectangular conductor 1. May be.

After drying, a baking process is performed. In the baking process, the electrodeposition resin layer is cured in the baking furnace 18 to form a semiconductive layer. The baking temperature is usually 100 to 700 ° C, preferably 150 to 600 ° C, more preferably 170 to 200 ° C. It should be noted that baking and curing in the baking furnace 18 may be omitted if the baking process is sufficiently performed in the drying process.
In this way, a flat electric wire having a semiconductive layer formed on the flat electric conductor is obtained, and the obtained flat electric wire is wound up by the winder 19. The flat electric wire thus obtained can have an excellent volume resistivity of 10 ² to 10 ¹⁰ Ω · cm in its semiconductive layer.

  As mentioned above, although the manufacturing method of the rectangular electric wire which concerns on this invention was demonstrated, in this invention, one or more insulating layers can be provided on a semiconductive layer as mentioned above, and this insulating layer is insulation of above-mentioned polyurethane etc. The paint can be formed on the semiconductive layer by the same electrodeposition treatment as described above. Furthermore, for the purpose of facilitating coil winding work, a self-bonding layer can be provided on the insulating layer. The self-bonding layer can be formed by an appropriate method such as a method in which varnish is dip-coated and then varnished with felt or the like.

  Examples of the present invention will be described in detail below, but the present invention is not limited to these examples.

(Example 1)
A copper rectangular conductor having a width of 2 mm and a thickness of 200 μm was introduced into the electrodeposition apparatus at a linear speed of 20 m / min on the anode side to form an electrodeposition resin layer. The electrodeposition conditions are as follows.
・ Cathode: Platinum,
DC voltage: 80V
-Varnish temperature: 25 ° C.
For the formation of the electrodeposition resin layer, a polyurethane water dispersion varnish (manufactured by Nihon Point Co., Ltd., urethane electrodeposition paint (model number: PSQ)) kneaded with carbon black powder was used as a semiconductive paint. The carbon black powder accounted for 38% by weight of the total solid content of the semiconductive paint, and the total solid content of the semiconductive paint was 20% by weight.

Next, the rectangular conductor on which the electrodeposited resin layer is formed is dried at 100 ° C. and then baked at 180 ° C., so that the film thickness A at the corner is 7.5 μm and the film thickness B at the flat portion is 9 μm. A flat electric wire having a semiconductive layer of 0.0 μm was obtained. The volume resistivity of the semiconductive layer was 4.0 × 10 ⁵ Ω · cm.

(Example 2)
Instead of the semiconductive paint of Example 1, the carbon black powder accounts for 54% by weight of the total solid content of the semiconductive paint, and the total solid content of the semiconductive paint is 20% by weight. A rectangular electric wire was obtained in the same manner as in Example 1 except that was used. In the obtained electric wire, the film thickness A of the corner portion is 9.5 μm, the film thickness B of the flat portion is 11.0 μm, and the volume resistivity of the semiconductive layer is 2.0 × 10 ³ Ω · cm. Met.

(Comparative Example 1)
A rectangular electric wire was obtained in the same manner as in Example 1 except that the resin layer was formed around the copper rectangular conductor by dipping using polyurethane-based dipping paint instead of electrodeposition. In the obtained electric wire, the film thickness A of the corner portion is 1.5 μm, the film thickness B of the flat portion is 8.0 μm, and the volume resistivity of the semiconductive layer is 8.0 × 10 ⁷ Ω · cm. Met.

It is sectional drawing which shows one Embodiment of the flat electric wire which has a semiconductive layer of this invention. It is a schematic cross section which shows an example of the manufacturing process of the flat electric wire which has a semiconductive layer of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Conductor with a flat rectangular shape, 2 ... Semiconductive layer, 3 ... Corner part, 4 ... Flat part, 5 ... Intersection of 2 sides which comprise a conductor, 6 ... Semiconductive layer surface, 7 ... One side which comprises a conductor, 10: Flat electric wire having a semiconductive layer, A: Film thickness of corner portion, B: Film thickness of flat portion

Claims (9)

A conductor having a rectangular cross section and a semiconductive layer formed on the outer periphery thereof,
The film thickness A of the corner portion of the semiconductive layer and the film thickness B of the flat portion of the semiconductive layer are
A flat electric wire having a semiconductive layer that satisfies the relationship of A ≧ 0.6 × B.   The flat electric wire according to claim 1, wherein the film thickness B is 30 μm or less. The flat electric wire according to claim 1 or 2, wherein the semiconductive layer has a volume resistivity of 10 ² to 10 ¹⁰ Ω · cm.   The flat electric wire according to any one of claims 1 to 3, wherein the semiconductive layer is formed by electrodeposition of a semiconductive paint.   The flat electric wire according to claim 4, wherein the semiconductive paint is an insulating paint containing a conductive material.   The rectangular electric wire according to claim 5, wherein the ratio of the conductive material to the total solid content of the semiconductive paint is 35 to 55 wt%.   A method for producing a rectangular electric wire having a semiconductive layer, in which a semiconductive paint is electrodeposited and baked on the outer periphery of a conductor having a rectangular cross section to form a semiconductive layer.   The manufacturing method of Claim 7 using the insulating coating material containing an electroconductive material as a semiconductive coating material.   The manufacturing method of Claim 8 whose ratio of the electroconductive material which occupies for the total solid of a semiconductive coating material is 35 to 55 weight%.

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