JP7053427B2 - Enamel wire manufacturing method - Google Patents

Description

The present invention relates to a method for producing an enamel wire containing carbon nanotubes.

Although carbon nanotubes are lightweight, they have high mechanical strength and have higher conductivity than copper, which is generally used as a conductive material. Therefore, it is attracting attention for its use as a conductive material.

On the other hand, the enamel wire is widely used as a coil wire for electric devices such as motors, transformers, and deflection yokes (for example, Patent Document 1). Enamel wire is an electric wire in which a conductor is baked with a natural resin or synthetic resin insulating paint.

Japanese Unexamined Patent Publication No. 8-185716

However, enamel wires using carbon nanotubes have not yet been put into practical use.

Therefore, the present invention has been made to solve at least a part of the above-mentioned problems, and can be realized as the following aspects or application examples.

[ 1 ] The method for producing an enamel wire according to the present invention is as follows.
A molding process in which a conductor , which is an aggregate of a plurality of carbon nanotubes, is pulled out from a bobbin and the roundness of the conductor is adjusted.
After the molding step, a cleaning step of cleaning the conductor with an organic solvent and
An annealing step of heating the conductor after the cleaning step to remove the organic solvent adhering to the conductor, and a step of annealing.
A coating step of applying paint to the conductor after the annealing step, and a coating step of applying the paint to the conductor.
A baking step of baking the paint applied to the conductor in the coating step, and a baking step of baking the paint.
Including
The conductor is a twisted yarn obtained by twisting spun yarns of a plurality of carbon nanotubes, a bundle of the plurality of twisted yarns, or the twisted yarn or the outer surface of the bundle obtained by metal plating.
Each step is executed without being wound around the bobbin from the molding step to the baking step on the conductor.
In the molding step, a part of the outer surface of the conductor comes into contact with the inner surface of the die hole having a circular cross section and the curved groove of at least two rollers facing each other, and the portion protruding from the outer surface of the conductor is the die. 1. The roundness of the conductor is 1.0 or more by being pressed and deformed by the inner surface of the hole and the groove of the roller. Adjust to 25 or less,
The tensile stress on the conductor in the molding step is 200 MPa or more and 2000 MPa or less.
The viscosity of the coating material in the coating step is characterized by being 0.5 dPa · s or more and 50 dPa · s or less.

It is a figure which shows a part of the enamel wire which concerns on this embodiment in a cross section. It is a schematic diagram of an example of the manufacturing apparatus for carrying out the manufacturing method of the enamel wire which concerns on this embodiment. It is sectional drawing of the die used in the manufacturing method of the enamel wire which concerns on this embodiment. It is a perspective view of the roller used in the manufacturing method of the enamel wire which concerns on this embodiment. It is a photograph which took the conductor of Example 1 at 500 times. It is a photograph which took the enamel wire of Example 1 at 500 times. It is a photograph which took the cut surface of the enamel wire of Example 1 at 1000 times . It is a photograph which took the conductor of Example 2 at 500 times. It is a photograph which took the enamel wire of Example 2 at 500 times. It is a photograph which took the cut surface of the enamel wire of Example 2 at a magnification of 500 times. It is a photograph of the enamel wire of Comparative Example 1 taken at 500 times. It is a photograph which took the cross section of the enamel wire of the comparative example 1 at a magnification of 500 times. It is a graph which shows the relationship between the electric resistance and the temperature of an Example and a comparative example. It is a graph which shows the relationship between the impedance and the frequency of an Example and a comparative example.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. The embodiments described below do not unreasonably limit the content of the present invention described in the claims. Moreover, not all of the configurations described below are essential constituent requirements of the present invention.

1. 1. Enamel wire The enamel wire 10 according to the embodiment of the present invention will be described with reference to FIG. FIG. 1 is a cross-sectional view showing a part of the enamel wire 10 according to the present embodiment. FIG. 1 shows a greatly deformed shape for explaining the roundness and the eccentricity.

The enamel wire 10 includes a conductor 20 which is an aggregate of a plurality of carbon nanotubes, and an insulating coating 30 which covers the conductor 20.

The enamel wire 10 is an electric wire having an insulating coating 30 formed by baking a paint on a wire which is a conductor 20 to cover the conductor. The enamel wire 10 is not limited to a wire having an insulating coating 30 directly coated on a wire which is a conductor 20, but also includes a wire having a metal plating on the outer surface of the conductor 20 coated with an insulating film 30.

The conductor 20 is an aggregate of a plurality of carbon nanotubes (hereinafter referred to as “CNT aggregate”). The CNT aggregate is a collection of a plurality of carbon nanotubes to form a single thread. The CNT aggregate may be a twisted yarn obtained by twisting spun yarns of carbon nanotubes spun by wet spinning or dry spinning, or may be a bundle of a plurality of twisted yarns . The CNT aggregates are assembled by the van der Waals force between the carbon nanotubes. The CNT aggregate may be one in which the outer layer of the twisted yarn is metal-plated, or the outer surface of a bundle of a plurality of twisted yarns is metal-plated. As the metal plating, known carbon nanotubes such as copper plating can be adopted. As the CNT aggregate, for example, a CNT twisted yarn manufactured by Hitachi Zosen Corporation, a CNT wire coated with a metal-coated CNT twisted yarn, a CNT twisted yarn manufactured by Murata Machinery Corporation, or the like can be adopted.

As the carbon nanotube, a metal type having excellent electrical conductivity can be used. The layer structure of the carbon nanotubes is not particularly limited, and may include single-walled and multi-walled (two or more layers) carbon nanotubes, and may be composed of only one of the single-walled carbon nanotubes and the multi-walled carbon nanotubes. The method for producing carbon nanotubes is not particularly limited, and those produced by a known method such as a vapor phase growth method can be used.

The diameter (wire diameter) of the conductor 20 can be, for example, 30 μm or more and 200 μm or less. If the diameter of the conductor 20 is 30 μm or more, it can be put into practical use as an enamel wire, and if it is 200 μm or less, it can be obtained as a CNT aggregate. As used herein, the term "wire diameter" refers to an arithmetic mean value obtained by measuring the diameters of three or more points at 1 m intervals along the longitudinal direction of a CNT aggregate with a laser micrometer (for example, LS9500 manufactured by KEYENCE CORPORATION).

The conductor 20 has a roundness of 1.0 or more and 1.5 or less. As shown in FIG. 1, for roundness, the diameter of the conductor 20 at an arbitrary position in the length direction of the conductor 20 is measured with a microscope, and the ratio of the maximum diameter D1 to the minimum diameter D2 (D1 / D2). Is. Since a plurality of carbon nanotubes are only bundled by van der Waals force in the CNT aggregate, the surface unevenness is large as it is. Moreover, carbon nanotubes are hydrophobic and do not easily get wet with enamel wire paint. Therefore, if a paint is applied to the conductor 20 having a roundness of more than 1.5, fine defects (for example, pinholes) may occur. It is more preferable that the conductor 20 has a roundness of 1.0 or more and 1.2 or less.

When the conductor 20 is a CNT aggregate coated with a metal plating such as copper, it is preferable that the surface of the conductor 20 (the surface of the copper plating) is smooth and the maximum height (Rz) is 5 μm or less. Since the surface of the conductor 20 has few irregularities, the insulating coating 30 can be satisfactorily formed. "Maximum height" is the sum of "maximum mountain height" and "maximum valley depth" of the contour curve specified in JIS B0601 (distance between the peak and valley bottom points), and is a microscope (Keyence "VHX"). -5000 ") can be analyzed and obtained by shape measurement software ("VHX-H4M "manufactured by KEYENCE CORPORATION). Further, for example, a magnified photograph of about 500 to 1000 times may be taken and the height and depth of the contour may be measured using a ruler.

The insulating coating 30 is an insulating coating that covers the conductor 20. As the material of the insulating film 30, polyurethane, polyvinylformal, polyurethane nylon, polyester, polyester nylon, polyesterimide, polyamideimide, polyesterimide / polyamideimide, polyimide and the like can be used.

The degree of unevenness of the insulating film 30 can be 1.0 or more and 2.0 or less. As shown in FIG. 1, the degree of eccentricity is the degree of eccentricity of the insulating coating 30. Specifically, the degree of deviation is measured by measuring the wall thickness of the insulating coating 30 on the virtual line passing through the center O of the enamel wire 10 with a microscope, and the ratio of the thickest wall thickness T1 to the thinnest wall thickness T2 (T1). / T2). When the degree of uneven thickness is 2.0 or less, the coating film uniformly covers the circumference of the conductor, and the insulation performance of the enamel wire can be ensured. If it deviates from this range, a defect may occur in a thin portion and the insulation may be deteriorated.

The wall thickness of the insulating coating 30 can be 5 μm or more. The wall thickness is the thickness from the surface of the conductor 20 to the outer surface of the insulating coating 30. When the wall thickness is 5 μm or more, the insulation performance of the enamel wire 10 can be ensured. Further, the wall thickness of the insulating coating 30 is preferably 5% or more of the wire diameter of the conductor 20. When the wall thickness is 5% or more of the wire diameter, the insulation performance of the enamel wire 10 can be ensured.

The enamel wire 10 can have an electric resistance at 0 ° C. to 200 ° C. measured by a resistance meter of 90% or more and 110% or less when the electric resistance at 20 ° C. is 100%. Generally, the electric resistance of the enamel wire of a metal conductor increases when the temperature is raised, but the electric resistance of the enamel wire according to the present embodiment does not change much with the temperature rise. Therefore, for example, it can be suitably adopted for nuclear reactors and space development applications.

The enamel wire 10 can have an impedance at 0 kHz to 200 kHz measured by an impedance measuring device of 80% or more and 120% or less when the impedance at 0 kHz is 100%. Generally, the impedance of the enamel wire of a metal conductor increases as the frequency is increased, but the impedance of the enamel wire according to the present embodiment does not change much with the frequency increase. Therefore, for example, it can be suitably used for a high frequency coil.

2. 2. Manufacturing method of enamel wire In the manufacturing method of enamel wire according to the present embodiment, a molding step of adjusting the roundness of a conductor which is an aggregate of a plurality of carbon nanotubes and a coating material are applied to the conductor obtained in the molding step. It includes a coating step and a baking step of baking the paint applied to the conductor in the coating step.

A method for manufacturing the enamel wire 10 according to the embodiment of the present invention will be described with reference to FIGS. 2 to 4. FIG. 2 is a schematic view of an example of a manufacturing apparatus 100 for carrying out the method for manufacturing the enamel wire 10 according to the present embodiment, and FIG. 3 is a cross section of a die 600 used for the method for manufacturing the enamel wire 10 according to the present embodiment. FIG. 4 is a perspective view of a roller 610 used in the method for manufacturing an enamel wire 10 according to the present embodiment.

As shown in FIG. 2, the manufacturing apparatus 100 applies paint to the bobbin 50 around which the conductor 20 is wound, the molding portion 60 for molding the conductor 20 drawn from the bobbin 50, and the conductor 20 molded by the molding portion 60. It has a coating unit 70 for coating, a baking unit 80 for baking paint, and a winding unit 90 for winding up an insulatingly coated enamel wire 10.

The conductor 20 wound around the bobbin 50 is a CNT aggregate. The conductor 20 is pulled out from the bobbin 50 and introduced into the molded portion 60.

The molding unit 60 carries out a molding process on the conductor 20. The molding step is a step of adjusting the roundness of the conductor 20, which is an aggregate of a plurality of carbon nanotubes. In the molding step, the surface of the conductor 20 and the molding member are brought into contact with each other to reduce the unevenness of the surface of the conductor 20 and bring the roundness of the conductor 20 close to 1.0. As the molding member of the molding portion 60, for example, the die 600 of FIG. 3 and the roller 610 of FIG. 4 can be adopted. In the molding portion 60, a plurality of dies 600 and / or rollers 610 may be arranged in series in order to gradually bring the roundness of the conductor 20 closer to 1.0.

As shown in FIG. 3, the outlet 604 of the die 600 is smaller than the diameter of the inlet 602. The inlet 602 and the outlet 604 are circular, and the die 600 has a truncated cone-shaped die hole 606 that gradually narrows from the inlet 602 to the outlet 604. The diameter of the inlet 602 is larger than the maximum diameter of the conductor 20, for example, about 1.5 times the maximum diameter of the conductor 20. The diameter of the outlet 604 is, for example, 1.0 to 1.5 times the maximum diameter of the conductor 20, and particularly preferably about 1.2 times the maximum diameter of the conductor 20.

In the molding process, the roundness of the conductor 20 is adjusted to 1.0 or more and 1.5 or less. When the conductor 20 is pulled out from the die 600, the conductor 20 is molded into a cross-sectional shape close to a perfect circle while contacting the die hole 606 having a circular cross section. A part of the outer surface of the conductor 20 comes into contact with the inner surface of the die hole 606, and in particular, the protruding portion of the conductor 20 is pressed against the inner surface of the die hole 606 to be deformed and molded. Since the conductor 20 is simply a collection of a plurality of carbon nanotubes by a van der Waals force, the conductor 20 can be easily deformed by contact with the die hole 606.

Further, in the molding step, even when the surface of the conductor 20 has a metal plating film, the unevenness of the surface can be reduced.

The tensile stress on the conductor 20 in the molding step is preferably 200 MPa or more and 2000 MPa or less. Since the conductor 20 is an aggregate of CNTs, it breaks when an excessive tensile stress is applied to the conductor 20, so it is necessary to adjust the feed rate of the conductor 20 to maintain the tensile stress in the molding process at a relatively small value. .. In the case of a general conductor wire processing die, the conductor wire is drawn, but the conductor 20 according to the present embodiment is not drawn. A molding process is performed in order to arrange the outer shape of the conductor 20 into a shape close to a perfect circle.

Further, the roller 610 shown in FIG. 4 may be used instead of the die 600 or continuously before and after the die 600. The roller 610 has two rollers 610 so as to sandwich the conductor 20 drawn from the bobbin 50. The two opposing rollers 610 are spaced apart from each other and rotate in the direction in which the conductor 20 is fed. The roller 610 has a groove 612 curved in an arcuate cross section. The grooves 612 facing each other are arranged with a distance slightly larger than the maximum diameter of the conductor 20. The groove 612 contacts the conductor 20 passing between the rollers 610 and forms the conductor 20 into a cross-sectional shape close to a perfect circle. In FIG. 4, the two rollers 610 are arranged vertically spaced apart, but the two rollers 610 may be arranged horizontally spaced apart. Further, two sets of rollers 610 arranged in the vertical direction and rollers 610 arranged in the horizontal direction may be arranged side by side in series and come into contact with the conductor 20 from two directions.

The coating unit 70 executes a coating step of applying paint to the conductor 20 molded to a predetermined roundness in the molding step. As the paint to be applied by the coating unit 70, a paint in which the resin of the insulating coating 30 described above is dissolved in a solvent is used.

The viscosity of the paint in the coating step can be 0.5 dPa · s or more and 50 dPa · s or less. The viscosity of the paint can be measured according to JIS C2103, for example, using a digital rotary viscometer (Viscometer) manufactured by Rion Co., Ltd. If the viscosity of the paint is 0.5 dPa · s or less, it is not preferable because the paint becomes dripping before firing in the baking portion 80 and causes poor thickness unevenness. If it is 50 dPa · s or more, it becomes a conductor. It is not preferable because excessive stress is applied and it causes breakage.

The baking unit 80 executes a baking step of baking the paint applied to the conductor 20 in the coating step. The baking temperature is set to an appropriate temperature according to the type of paint.

By repeating the coating process and the baking process a plurality of times, the insulating film 30 composed of a plurality of layers can be formed on the conductor 20. By applying the insulating film 30 times a plurality of times, the wall thickness of the insulating film 30 can be made uniform. Specifically, the conductor 20 that has passed through the coating portion 70 and the baking portion 80 is returned to the coating portion 70 again, and the coating step and the baking step are repeated. For example, the insulating coating 30 can be formed by five or more coating steps and baking steps.

After the molding step and before the coating step, a cleaning step of cleaning the conductor 20 with an organic solvent and an annealing step of heating the conductor 20 to remove the organic solvent adhering to the conductor 20 may be further included. The cleaning step can wash away impurities adhering to the conductor 20. When the conductor 20 is not coated with metal plating, the organic solvent enters the gap inside the conductor 20 in the cleaning step, and the organic solvent is removed in the annealing step, so that the gap inside the conductor 20 is reduced. As a result, the porosity becomes low. If the porosity of the conductor 20 is low, the electrical resistance of the enamel wire 10 can be kept low. Further, if the porosity of the conductor 20 is low, the tensile strength of the enamel wire 10 is improved.

The annealing step heats the organic solvent adhering to the conductor 20 to a temperature at which it can be volatilized.

As the organic solvent, acetone is preferable when the conductor 20 is not coated with metal plating. When the conductor 20 is a CNT aggregate coated with a metal plating such as copper, in addition to acetone, for example, ethanol, methanol, isopropanol, ethylene dichloride or chloroform may be used as the organic solvent.

(1) Preparation of Samples of Examples Examples 1 to 3 are carried out by molding commercially available CNT aggregates as Examples 1 to 3 into the roundness shown in Table 1, applying an insulating film, and baking them. A sample of the enamel wire of Example 3 was obtained.

The "conductor" of Example 1 is a "CNT wire" having a wire diameter of 50 μm manufactured by Hitachi Zosen Corporation, and the "paint" is a five-layer polyurethane insulating film using a viscosity of 0.5 dPa · s manufactured by Totoku Toryo Co., Ltd. (Average wall thickness 7 μm) was formed.

The "conductor" of Example 2 is "with CNT wire Cu plating" having a wire diameter of 40 μm and a copper plating thickness of 1 μm (one side) manufactured by Hitachi Shipbuilding Co., Ltd., and the “paint” has a viscosity of 0.5 dPa manufactured by Totoku Toryo Co., Ltd. -S was used to form a five-layer polyurethane insulating coating (average wall thickness 8.5 μm).

The "conductor" of Example 3 is a "CNT yarn" having a wire diameter of 100 μm manufactured by Murata Machinery Co., Ltd., and the "paint" is a five-layer polyurethane insulating film using a viscosity of 0.5 dPa · s manufactured by Totoku Toryo Co., Ltd. (Average wall thickness 12 μm) was formed.

(2) Preparation of sample of comparative example As comparative example 1, the "conductor" is a CNT aggregate with a wire diameter of 120 μm manufactured by Meijo Nanocarbon Co., Ltd., without adjusting the roundness and without cleaning with an organic solvent. A five-layer polyurethane insulating film (average wall thickness 5 μm) was formed using a paint having a viscosity of 0.5 dPa · s manufactured by Paint Co., Ltd.

As Comparative Example 2, a type 2 enamel wire having a polyurethane insulating film (average wall thickness of 5 μm) formed on a copper wire having a wire diameter of 30 μm was used.

As Comparative Example 3, a polyurethane insulating film (average wall thickness 5 μm) was formed on a carbon fiber assembly wire (wire diameter 230 μm) manufactured by Sakai Sangyo Co., Ltd.

(3) Measurement of various dimensions The conductors of Examples 1 to 3 and Comparative Examples 1 to 3 were photographed with a microscope, and the wire diameter (“conductor diameter”) was measured with image measurement software. 5 and 8 are photographs taken by magnifying the appearance of the CNT aggregates of Examples 1 and 2 at a magnification of 500 times. FIG. 11 is a photograph taken by magnifying the appearance of the CNT aggregate of Comparative Example 1 by 500 times. The conductors of Examples 1 to 3 are the dimensions after the molding step, and the conductors of Comparative Examples 1 to 3 are the dimensions in the state where the molding step is not performed. The enamel wire was rotated at the same position in the length direction of each conductor, the wire diameter was measured at five points, and the roundness (D1 / D2) was calculated from the maximum diameter D1 and the minimum diameter D2 of the measurement results. The wire diameter of the enamel wire is shown in Tables 2 and 3 as the "finishing diameter". The roundness was calculated at 10 points in the length direction of each conductor, and the largest roundness among them is shown in Tables 1 to 3.

The cross sections of Examples 1 to 3 and Comparative Examples 1 to 3 in which the enamel wires were cut were photographed using a microscope, and the wall thicknesses at five or more points were measured with image measurement software. From the measurement results, the ratio (T1 / T2) of the thickest wall thickness T1 and the thinnest wall thickness T2 was determined as the degree of deviation. Measurements were made at 10 points in the length direction of each conductor, and the largest degree of unevenness among them is shown in Tables 1 to 3.

(4) Evaluation of Insulation Film FIG. 6 is a photograph taken by magnifying the appearance of the enamel wire of Example 1 by 500 times, and FIG. 7 is a photograph taken by magnifying the cut surface of the enamel wire of Example 1 by 1000 times. It is a photograph taken, FIG. 8 is a photograph taken by magnifying the appearance of the enamel wire of Example 2 by 500 times, and FIG. 9 is a photograph taken by magnifying the cut surface of the enamel wire of Example 2 by 1000 times. It is a photograph that was taken. As shown in Tables 2 and 3, the enamel wires of Examples 1 to 3 and Comparative Example 2 had a degree of deviation of 2.0 or less, and no defects such as pinholes were found even when the enlarged photographs were observed. ..

FIG. 12 is a photograph taken by magnifying the cross section of the enamel wire of Comparative Example 1 by 500 times. As shown in FIG. 12, Comparative Example 1 has a flat cross section and many surface irregularities, and accompanying defects of the insulating coating are observed in various places. The roundness of the conductor of Comparative Example 1 was 1.9, and the degree of unevenness of the enamel wire could not be measured.

(5) Mechanical properties For the conductor and enamel wire samples of Examples 1 to 3 and Comparative Examples 1 to 3, JIS C3202 test pieces were used at 23 ± 2 ° C. using a tensile tester manufactured by Orientec Co., Ltd. , A tensile test was performed based on JIS C3216 at a standard line distance of 200 mm and a tensile speed of 5 ± 1 mm / sec, and the tensile strength (N) and the breaking load (gf) were measured. The measurement results are shown in Tables 1 to 3.

(6) Measurement and evaluation of wire resistance With respect to the enamel wire samples of Examples 1 to 3 and Comparative Examples 2 and 3, the electrical resistance was measured based on JIS C3216 using a resistance meter manufactured by Tsuruga Electric Co., Ltd., and the measurement thereof. The results are shown in FIG. FIG. 13 shows the change (resistance ratio) of the electric resistance from 0 ° C. to 200 ° C. when the electric resistance at 20 ° C. is 100%. According to FIG. 13, the electric resistance of the enamel wire of Comparative Example 2 increases as the temperature rises, whereas the electric resistance of the enamel wires of Examples 1 to 3 and Comparative Example 3 has a temperature of 0 ° C to 200 ° C. There was no change of ± 20% even if it changed. Specifically, the changes in electrical resistance of each example at 0 ° C. and 200 ° C. were 102% and 86% in Example 1, 101% and 87% in Example 2, and 102% and 84% in Example 3. there were.

(7) Impedance measurement and evaluation For the enamel wire samples of Examples 1 to 3 and Comparative Examples 2 and 3, the electrical resistance was measured based on JIS C3216 using an impedance measuring instrument manufactured by GW Instek, and the electric resistance was measured from 0 kHz to 0 kHz. Impedance at 200 kHz was measured, and the measurement results are shown in FIG. FIG. 14 shows the change in impedance from 0 kHz to 200 kHz when the impedance at 0 kHz is 100%. According to FIG. 14, the impedance of the enamel wire of Comparative Example 2 increases as the frequency increases, whereas the impedance of the enamel wire of Examples 1 to 3 and Comparative Example 3 decreases as the frequency increases to 200 kHz. Even so, it did not fall below 90%. In particular, the impedances of the enamel wires of Examples 1 to 3 showed almost the same tendency. Specifically, the changes in impedance at 0 kHz and 200 kHz were 100% and 99% in Example 1, 100% and 96% in Example 2, and 100% and 92% in Example 3.

(8) Effect of organic solvent When "CNT yarn" manufactured by Murata Machinery Co., Ltd. was immersed in acetone, the wire diameter was reduced from 44.4 μm to 39.5 μm. When the conductor was not coated with metal plating, the porosity decreased at the same time as washing with acetone. Washing with ethanol, methanol, isopropanol, ethylene dichloride and chloroform instead of acetone did not show any decrease in porosity.

The present invention is not limited to the above-described embodiment, and various modifications are possible. For example, the present invention includes substantially the same configurations as those described in the embodiments (eg, configurations with the same function, method, and result, or configurations with the same purpose and effect). The present invention also includes a configuration in which a non-essential part of the configuration described in the embodiment is replaced. Further, the present invention includes a configuration having the same action and effect as the configuration described in the embodiment or a configuration capable of achieving the same object. Further, the present invention includes a configuration in which a known technique is added to the configuration described in the embodiment.

10 ... enamel wire, 20 ... conductor, 30 ... insulating film, 50 ... bobbin, 60 ... molding part, 70 ... coating part, 80 ... baking part, 90 ... winding part, 100 ... manufacturing equipment, 600 ... die, 602 ... Entrance, 604 ... Exit, 606 ... Dice hole, 610 ... Roller, 612 ... Groove

Claims (1)

A molding process in which a conductor , which is an aggregate of a plurality of carbon nanotubes, is pulled out from a bobbin and the roundness of the conductor is adjusted.
After the molding step, a cleaning step of cleaning the conductor with an organic solvent and
An annealing step of heating the conductor after the cleaning step to remove the organic solvent adhering to the conductor, and a step of annealing.
A coating step of applying paint to the conductor after the annealing step, and a coating step of applying the paint to the conductor.
A baking step of baking the paint applied to the conductor in the coating step, and a baking step of baking the paint.
Including
The conductor is a twisted yarn obtained by twisting spun yarns of a plurality of carbon nanotubes, a bundle of the plurality of twisted yarns, or a twisted yarn or an outer surface of the bundle obtained by metal plating.
Each step is executed without being wound around the bobbin from the molding step to the baking step on the conductor.
In the molding step, a part of the outer surface of the conductor comes into contact with the inner surface of the die hole having a circular cross section and the curved groove of at least two rollers facing each other, and the portion protruding from the outer surface of the conductor is the die. 1. The roundness of the conductor is 1.0 or more by being pressed and deformed by the inner surface of the hole and the groove of the roller. Adjust to 25 or less,
The tensile stress on the conductor in the molding step is 200 MPa or more and 2000 MPa or less.
A method for producing an enamel wire, wherein the viscosity of the coating material in the coating step is 0.5 dPa · s or more and 50 dPa · s or less.

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