JPH09282948A - Insulated wire and manufacturing method thereof - Google Patents

Abstract

(57) [Abstract] [Problem] To prevent uneven thickness of the insulating film, to ensure the electrical characteristics without variation, and to ensure the insulation guarantee value without making the insulating film thicker than necessary. To provide an insulated wire capable of preventing an increase in size and an increase in coil resistance value. SOLUTION: A polyester imide resin is the main component,
An insulating coating having a solid content concentration of 40 to 50% by weight and a viscosity at 50 ° C. of 10 to 60 dPa · s is applied and baked on the conductor wire a plurality of times by a die to form an insulating film around the conductor wire, An insulated wire in which the thickness unevenness of the coating formed by one coating and baking is 1.5 or less and the thickness unevenness of the insulating coating is 1.5 or less.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an insulated wire used for manufacturing a coil such as a deflection yoke and a manufacturing method thereof.

[0002]

2. Description of the Related Art Conventionally, an insulated wire has been manufactured by applying an insulating paint obtained by dissolving a thermosetting resin together with a curing agent in a solvent onto a conductor and baking it. In particular,
After applying the insulating paint to the conductor with a coating roller, pass it through a die to apply the insulating paint with a predetermined thickness around the conductor, and pass it through a heating furnace to burn the insulating paint onto the conductor. An insulating film is formed. Usually, the coating and baking process is repeated about 6 to 8 times to form an insulating film with a predetermined thickness around the conductor wire. This method for producing an insulated wire has the advantages that any resin that can be dissolved in a solvent can be used as the insulating coating, and that the viscosity of the insulating coating required for coating can be reduced.

[0003]

However, in the conventional insulated wire manufactured by the above-mentioned method, the electrical characteristics, particularly the breakdown time in the relationship of applied voltage-breakdown time (Vt characteristic), that is, Variations in the life of the insulated wire in the high frequency region are likely to occur. Therefore, in the past, in order to ensure the electrical characteristics of the insulated wire, the insulation guarantee value was secured by making the thickness of the insulation film formed on the conductor wire thicker than the design value. However, if the insulation film becomes thicker, if a coil is made from this insulated wire, the coil will become thicker and the length of the insulated wire will become longer, and the outer shape of the coil will become unnecessarily large, resulting in coil resistance. It causes a high value. From the recent demand for lighter, thinner, shorter, and smaller electronic devices, it is desired to reduce the diameter of the coil and reduce the coil resistance value.By keeping the insulation guarantee value, the film thickness of the insulated wire can be reduced. There has been a demand for the development of an insulated wire that can prevent the coil diameter from increasing and the coil resistance value from increasing due to an increase in the thickness of the insulating film.

In order to obtain the insulated wire as described above, it is effective to reduce the uneven thickness of the insulating film formed on the conductor. Regarding the uneven thickness of the insulating film, for example, in JP-A-54-87885, the conductor is allowed to pass through a liquid tank of the insulating coating material which has been heated and melted, and then freely movable provided in the heating chamber. A method for producing an insulated electric wire, which comprises squeezing with an unfixed die, is also disclosed in JP-A-4-355.
JP-A No. 007 discloses a heat-resistant material containing a polyborosiloxane resin as a main component, and a silicone-based or paraffin-based leveling agent as an active ingredient in an amount of 0.02 to 2.5 parts by weight per 100 parts by weight of the polyborosiloxane resin. A heat-resistant insulated wire in which a coating / baking layer made of a heat-resistant paint is provided directly on a conductor or through another insulating coating is further disclosed in Japanese Patent Application Laid-Open No. 7-187
JP-A-282661 discloses a method for producing an insulated wire in which a synthetic resin-based enamel paint is applied to a conductive wire to be coated and baked, and the wire to be coated is inverted and turned upside down twice or more. There is disclosed a method of manufacturing the insulated wire.

In the method of manufacturing an insulated wire disclosed in Japanese Patent Laid-Open No. 54-87885, the dice are floated so that the die can move freely in the heating chamber to reduce the uneven thickness of the insulating film. Since the manufacturing method is quite complicated, the insulated wire manufactured by this method has a large variation in the uneven thickness in the longitudinal direction. In addition, JP-A-4-35500
The insulated wire disclosed in Japanese Patent No. 7 is intended to improve the wettability of the paint with respect to the conductor and prevent uneven thickness by adding a leveling agent to the insulating paint containing polyborosiloxane resin as a main component. Since the resin has poor mechanical properties such as flexibility and adhesion of the insulated wire as compared with polyesterimide resin, it can be used only for a specific purpose. Further, in the method of manufacturing an insulated wire disclosed in Japanese Patent Laid-Open No. 7-282261, two electric baking furnaces are used, and the electric wires are turned upside down and baked, thereby offsetting the uneven thickness due to a single application baking to cancel the total deviation. Although it is intended to reduce the thickness ratio, the uneven thickness of the coating is not fundamentally improved.
There is a problem in that the uneven thickness ratio causes the uneven thickness of the insulated wire to vary greatly in the longitudinal direction.

In view of the above points, the present invention suppresses the uneven thickness of the insulating coating on the insulated wire to ensure the insulation guarantee value without variation in electrical characteristics and without increasing the thickness of the insulating coating more than necessary. In this way, it is possible to prevent an increase in diameter due to coil winding thickening, and to prevent an increase in coil resistance value, and an insulated wire that can easily manufacture an insulated wire having such excellent electrical characteristics. It is intended to provide a manufacturing method of.

[0007]

In order to solve the above-mentioned object, an insulated wire according to the present invention comprises a polyesterimide resin as a main component and a solid content concentration of 40 to 50% by weight.
An insulating coating material having a viscosity of 10 to 60 dPa · s at a temperature of ℃ is applied and baked on a conductive wire a plurality of times by a die to form an insulating coating film around the conductive wire, and the uneven thickness of the insulating coating film is 1.5 or less. Is. The thickness deviation of the insulating film is more preferably 1.3 or less. Also, the average thickness deviation of the insulating coating per 1 m of the electric wire is 1.5 or less, more preferably 1.3 or less.

Here, the "unevenness" of the insulating film is as shown in FIG.
As shown in, the degree of eccentricity of the insulating coating 2 with respect to the axis O of the conductor 1, specifically, the ratio (b / a) of the thickness a of the thin portion and the thick portion b of the insulating coating 2 Say. Conventionally, in the insulated electric wire manufactured by the above method, the thickness of the insulating coating 2 on the conductor 1 is uneven, and the insulating coating 2 is largely eccentric with respect to the axial center O of the conductor 1. The uneven thickness (b / a) reached about 1.5 to 2.0. However, when the thickness deviation of the insulating film exceeds 1.5, the electrical characteristics deteriorate. In particular, the breakdown time in the relationship of applied voltage-breakdown time (Vt characteristic) is significantly reduced. That is, the life of the insulated wire in the high frequency region is shortened. Therefore, in order to secure the minimum guaranteed thickness (effective coating thickness) in order to secure the insulation guaranteed value, if the entire insulating coating is thickened with the thin portion as the standard,
As a result, the diameter of the insulated wire becomes larger, and the coil that uses this insulated wire becomes thicker and the outer diameter of the coil becomes unnecessarily large.The length of the insulated wire used also becomes longer, resulting in a larger coil outer diameter and coil resistance. The value becomes high. In this respect, according to the present invention, the polyester imide resin is the main component, and the solid content concentration is 40 to 50% by weight.
By applying an insulating coating having a viscosity of 10 to 60 dPa · s at a temperature of 10 to 60 dPa · s on the conductive wire with a die to form an insulating coating around the conductive wire, the uneven thickness of the insulating coating is set within the above range. Since the variation in the electrical characteristics of the electric wire due to the uneven thickness of the insulating film is suppressed, it is possible to reduce the thickness of the insulating film as a whole while ensuring the guaranteed insulation value. As a result, it is possible to prevent the diameter from increasing and the resistance value from increasing due to the thickening of the coil.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The tendency of uneven thickness of the insulating film in the insulated wire manufactured by the above method becomes more remarkable as more paint is applied at one time, and as the number of times of baking is increased, The deviation of the coating film per layer is added, and the uneven thickness tendency of the insulating film in the finally obtained insulated wire becomes remarkable. The cause of the uneven thickness of the coating film is that the dice are not installed correctly with respect to the conductive wire, there is a problem in the equipment such as the temperature distribution in the baking furnace is not uniform, and the wettability of the paint to the conductive wire is poor. However, the solid content concentration and viscosity of the insulating coating used are also one of the main causes. That is, when the solid content concentration of the coating material is increased, the thickness of the coating film by one application and baking increases, and the number of times of application decreases, but the thickness of the coating film by one application and baking increases, resulting in uneven thickness of the coating film. Happens. That is, the uneven thickness tendency cannot be improved by merely increasing the solid content concentration of the coating material and reducing the number of coating times. However, if the solid content concentration is increased without increasing the viscosity of the insulating coating, it is possible to increase the thickness of the coating film by one coating and reduce the number of coatings at the same time.
The uneven thickness can also be reduced, and the insulated wire in which the uneven thickness of the insulating film is 1.5 or less as described above can be easily manufactured.

Specifically, the insulating coating material has a solid content concentration of 40 to 50% by weight and a viscosity at 50 ° C. of 10 to 60.
An insulated electric wire having a thickness deviation in the above range can be manufactured by using a material having a dPa · s of about dPa · s and applying it on the conductive wire at a coating temperature of 45 ° C. or higher, preferably about 50 ° C. When the solid content concentration of the insulating coating is 40% by weight or less, the thickness of the coating film formed by one application is thin and the number of applications increases, which not only decreases productivity but also increases the number of applications. The unevenness of the coating film is added and the effect of improving uneven thickness is reduced. Also, when the solid content concentration is 50% by weight or more, uneven thickness is likely to occur, and at the same time, a foaming phenomenon may occur during baking. Therefore, the solid content concentration of the insulating paint is preferably within the above range. On the other hand, when the viscosity is above the above range, the resistance at the time of passing through the die may increase and the conductor wire may be elongated.

Any insulating paint can be used as long as it has the above-mentioned solid content concentration and viscosity, when the insulated wire of the present invention is manufactured.
It is preferable to use a thermosetting resin, which is generally used for insulated wires, dissolved in a solvent together with a curing agent. Examples of the thermosetting resin include polyester resins such as polyester resin, polyesterimide resin, polyesteramide resin, and polyesteramideimide resin, polyurethane resin, and alkyd resin. These resins may be used alone or in combination of two or more kinds. Can be mixed and used.
Among these thermosetting resins, polyester resins are preferable, and polyesterimide resins are particularly preferable. Further, the thermosetting resin and the thermoplastic resin as described above may be used in combination.

Next, as a curing agent component of the thermosetting resin, titanium tetraalkoxide or a derivative thereof, for example, a chelate compound of titanium tetraalkoxide, a siato compound, a titanium dialkoxy diphenolate compound, a titanium bis chelate compound, etc. Among these, titanium tetraalkoxide compounds are preferable, and among them, titanium tetrabutoxide is particularly preferable. As the curing agent, in addition to the above, cobalt, manganese, lead, zinc,
Similar curing can be obtained by using octoate such as calcium, nickel, lithium, tin, lanthanum, potassium, or sodium, naphthate, or linoleate together. The above-mentioned curing agent is generally used by dissolving or dispersing it in a solvent.

Further, as the solvent prepared by dissolving the above-mentioned thermosetting resin and curing agent, any good solvent can be used, and for example, cresol, phenol, xinolate, N, There are N-dimethylformamide, N, N-dimethylacetamide, N-methylpyrrolidone and the like, and these may be used alone or in combination of two or more kinds. Among these solvents, cresol type solvents are particularly preferable. If necessary, a poor solvent such as solvent naphtha and xylol can be used together with the above good solvent.

The above-mentioned insulating paint has a solid content concentration of 40 to 50 in order to reduce the uneven thickness of the insulating film.
It is preferable that the viscosity is adjusted to be 10 to 60 dPa · s at 50% by weight and the coating is applied on the conductor wire at this temperature. When the solid content concentration is higher than the above range, the viscosity is increased and not only the workability of coating on the running conductor is deteriorated but also the uneven thickness of the coating is increased. On the other hand, if the viscosity exceeds the above range, the workability of coating the conductive wire may be deteriorated and the thickness unevenness may be deteriorated as in the above case. Further, when the coating temperature is low, the viscosity of the coating material increases and the same problem as described above occurs, so the coating temperature is set to 45 ° C. or higher, preferably about 50 ° C. On the other hand, when the solid content concentration decreases, the viscosity of the paint also decreases and the work of applying it to the running conductors becomes easier, but the number of times of application and baking to obtain an insulating film of the desired thickness increases, and the insulation It is not preferable because the uneven thickness of the coating increases. Also, if the coating temperature is raised to lower the coating viscosity during coating, the coating viscosity will initially drop and the coating work will be easier, but the coating viscosity will change with time and the resulting insulated wire It is not preferable because the quality of the product varies.

As the die for producing the insulated wire of the present invention, any die which has been conventionally used for producing an insulated wire can be used.

When manufacturing the insulated wire of the present invention,
The thickness of the insulating film formed by coating and baking once is preferably 4.0 μm or less, and particularly preferably 2.0 to 3.0 μm. If the thickness of the coating after one application and baking is 4.0 μm or more, foaming occurs during baking,
Not only does the appearance of the insulated wire deteriorate, but the unevenness of the thickness of the insulating film formed by one-time application increases, and the unevenness of the finally formed insulating film also increases.
In addition, if the thickness of the coating formed by one coating baking is thin, the number of coatings increases, and the thickness deviation of the coating is added once, and the insulation coating in the insulated wire finally manufactured is added. It is not preferable because the degree of uneven thickness increases.

[0017]

【Example】

(Example 1) A polyester imide insulating coating A having a solid content concentration of 40% by weight and a viscosity of 25 dPa · s at 50 ° C. was applied at a coating temperature of 50 ° C. in a horizontal baking furnace at a maximum temperature of 50.
0 ° C., linear velocity 45 m / min. Then, coating and baking were repeated 8 times on a φ0.20 mm copper wire to obtain an insulated electric wire having a film thickness of 20 μm.

With respect to the obtained insulated wire, the uneven thickness of the insulating film was measured. Further, a test for softening resistance and a dielectric breakdown voltage was performed according to JIS C 3003 enamel copper wire and enamel aluminum wire test method.
In addition, Vt characteristic test, applied voltage 2kV frequency 80kH
The measurement was performed under z measurement conditions. These results are shown in Table 1 together with the characteristics of the insulating coating A used.

The thickness of the insulating film is the minimum scale 1 /
The insulation outer diameter and the conductor diameter were measured using a 1000 mm micrometer, and expressed as 1/2 of the difference between the insulation outer diameter and the conductor diameter. The thickness deviation is determined by making a cut on the circumference of the test piece with a sharp razor until reaching the conductor, and applying tension while cutting the line to cut. This was observed with a microscope having an appropriate magnification from the direction perpendicular to the line cut edge, and the thickness a of the thin portion and the thickness b of the thick portion of the film were measured and calculated by the following formula. Thickness deviation = b / a

(Example 2) Solid content concentration 42% by weight, 50
The polyesterimide-based insulating coating material B having a viscosity at 40 ° C. of 40 dPa · s was applied at a coating temperature of 50 ° C. in a horizontal baking furnace at a maximum temperature of 500 ° C. and a linear velocity of 45 m / min. And φ0.
Repeat coating and baking 8 times on a 20 mm copper wire to obtain a film thickness of 2
An insulated wire of 0 μm was obtained. Then, with respect to the obtained insulated wire, the uneven thickness of the insulating film and the characteristics of the insulated wire were examined in the same manner as in Example 1, and the results are shown in Table 1 together with the characteristics of the insulating coating material B used. .

(Example 3) Solid content concentration 45% by weight, 50
The polyester imide insulating coating C having a viscosity of 55 dPa · s at 50 ° C. was applied at a coating temperature of 50 ° C. in a horizontal baking furnace at a maximum temperature of 500 ° C. and a linear velocity of 45 m / min. And φ0.
Repeat coating and baking on a 20 mm copper wire 7 times to obtain a film thickness of 2
An insulated wire of 0 μm was obtained. Then, the obtained insulated wire was examined for uneven thickness of the insulating film and characteristics of the insulated wire by the same method as in Example 1, and the results are shown in Table 1 together with the characteristics of the insulating coating C used. .

Comparative Example 1 Solid content concentration 33% by weight, 40
The polyesterimide insulating coating D having a viscosity of 10 dPa · s at a temperature of 500 ° C. was applied at a coating temperature of 40 ° C. in a horizontal baking furnace at a maximum temperature of 500 ° C. and a linear velocity of 45 m / min. And φ0.
Repeat coating and baking on a 20 mm copper wire 7 times to obtain a film thickness of 2
An insulated wire of 0 μm was obtained. Then, with respect to the obtained insulated wire, the uneven thickness of the insulating film and the characteristics of the insulated wire were examined in the same manner as in Example 1, and the results are shown in Table 1 together with the characteristics of the insulating coating D used. It was

(Comparative Example 2) The same polyesterimide insulating coating D as in Comparative Example 1 was applied at a coating temperature of 40 ° C in a horizontal baking furnace at a maximum temperature of 500 ° C and a linear velocity of 45 m / min. And φ
The 0.20 mm copper wire was repeatedly applied and baked eight times to obtain an insulated electric wire having a film thickness of 20 μm. Then, the obtained insulated wire was examined for uneven thickness of the insulating film and characteristics of the insulated wire by the same method as in Example 1, and the results are shown in Table 1 together with the characteristics of the insulating coating D.

(Comparative Example 3) A polyesterimide insulating coating E (FS-) having a solid content of 33% by weight and a viscosity at 40 ° C. of 10 dPa · s, which gives an insulated wire of heat resistance category F, which has been conventionally used. 250 manufactured by Dainichiseika Kogyo Co., Ltd., with a coating temperature of 40 ° C. in a horizontal baking furnace at a maximum temperature of 500 ° C. and a linear velocity of 45 m / min. And φ0.20m
m copper wire is repeatedly applied and baked 7 times to obtain a film thickness of 20 μm
Insulated wire was obtained. Then, the obtained insulated wire was examined for uneven thickness of the insulating film and characteristics of the insulated wire by the same method as in Example 1, and the results are shown in Table 1 together with the characteristics of the insulating coating E used. .

[0025]

[Table 1]

[0026]

From the above results, it is understood that the insulated wire according to the present invention has excellent characteristics as compared with the conventional product having the same insulating film thickness. Therefore, the insulated wire of the present invention can prevent the coil diameter from increasing and the resistance value from increasing by making the film thickness thinner than the conventional insulated wire.

[Brief description of drawings]

FIG. 1 is an explanatory view of an electric wire showing a thickness deviation of an insulated electric wire. 1: Conductive wire, 2: Insulating film.

Claims (7)

[Claims] 1. A polyester imide resin as a main component,
An insulating coating having a solid content concentration of 40 to 50% by weight and a viscosity at 50 ° C. of 10 to 60 dPa · s is applied and baked on the conductor wire a plurality of times by a die to form an insulating film around the conductor wire, An insulated wire in which the uneven thickness of the insulating coating is 1.5 or less. 2. The insulated wire according to claim 1, wherein the coating formed by one coating and baking has a thickness deviation of 1.5 or less. 3. The insulated wire according to claim 1, wherein the thickness of the film formed by coating and baking the insulating coating material once is 4.0 μm or less. 4. The insulated wire according to claim 1, wherein the insulating coating material contains a polyesterimide resin as a main component and is dissolved in a solvent together with a curing agent. 5. The insulated wire according to claim 4, wherein the curing agent is a titanium tetraalkoxide compound. 6. A polyester imide resin as a main component,
This is dissolved in a solvent together with a curing agent, the solid content concentration is 40 to 50% by weight, and the viscosity at 50 ° C is 10 to 6
A method for producing an insulated wire, comprising forming an insulating coating around a conductor by applying an insulating coating of 0 dPa · s onto the conductor several times with a die and baking it. 7. The method for producing an insulated wire according to claim 6, wherein the curing agent is a titanium tetraalkoxide compound.