JP2003317549A - Rectangular insulated wire and coil using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rectangular insulated wire having good soldering characteristics and a coil formed by regularly winding the insulated wire and to further provide a rectangular insulated wire having heat resistance, insulation and flexibility equivalent or more than a conventional rectangular insulated wire as above and further having good soldering characteristics. <P>SOLUTION: The rectangular insulated wire comprises an insulating layer formed by electroplating a water dispersion resin varnish on the outer periphery of a rectangular sectional conductor. In this wire, the water dispersion resin varnish contains a urethane resin obtained by reacting at least a polyisocyanates with a polyols. The coil is by formed regularly winding the insulated wire. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flat insulated wire, and more particularly to a flat insulated wire having good solderability and a coil using the same.

[0002]

2. Description of the Related Art Conventionally, a rectangular insulated wire obtained by coating and baking an insulating varnish on a conductor having a rectangular cross section (hereinafter referred to as a rectangular wire) has been used for electric equipment. For example, as disclosed in Japanese Examined Patent Publication No. 7-120491, an ultrafine rectangular wire coated with an aqueous dispersion varnish of an epoxy-modified acrylic resin achieves a coating thickness (insulating layer) of several μm, and further, a conductor corner portion. Is also well covered.
In the case of aligned winding, the rectangular wire requires a smaller occupied area after lamination than the round wire, so in consideration of space saving and downsizing, the rectangular insulated wire is often used for the recent electric equipment parts. There is.

A rectangular insulated wire produced by applying a water-dispersed varnish of an epoxy-modified acrylic resin as an insulating layer to an ultra-fine rectangular wire and baking it is non-polluting because it is a water-dispersed emulsion type, and electrodeposition coating is possible. Is. The insulating film is tough and has excellent flexibility and insulation (breakdown voltage) required for electric wires. It has the characteristics of high continuous use temperature (heat resistance).

[0004] In addition, when a flat insulated wire is wound in a line and a terminal is processed (solder processing), a method that can be carried out in a short time is a solder bath (bath containing molten solder).
The method of immersing the end portion in is adopted. The flat insulated wire immersed in the solder bath has a mechanism in which the insulating layer is decomposed and solder is attached to the exposed conductor portion.

However, when soldering a rectangular insulated wire baked by applying the above water-dispersed varnish of epoxy-modified acrylic resin, a solder bath maintained at a temperature of 450 ° C. or higher is required, and a lower temperature is required. The held solder bath has a problem that the insulating layer cannot be removed well, and the insulating layer must be removed again by a physical method after the soldering process. Further, even with a solder bath at a temperature of about 450 ° C., the soldering process could not be carried out in a short time and the production efficiency was not good. When a solder bath having a temperature of 450 ° C. or higher is used, the soldering process can be completed in a short time, but there is a problem that the insulating layer in a portion where the soldering process is not desired is thermally deteriorated.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to provide a flat insulated wire having good soldering characteristics and a coil formed by winding it in a line, and further, as described above, it is equivalent to a conventional flat insulated wire. An object of the present invention is to provide a rectangular insulated wire having the above heat resistance, insulating properties, flexibility, and good soldering characteristics.

[0007]

[Means for Solving the Problems] The above problems are (1)
On the outer periphery of a conductor having a rectangular cross section, in a rectangular insulated wire in which an insulating layer is formed by electrodeposition of a water-dispersed resin varnish, the water-dispersed resin varnish is a urethane resin obtained by reacting at least polyisocyanates and polyols. A flat insulated wire characterized by containing. (2) The flat insulated wire according to claim 1, wherein the polyol of the urethane resin obtained by reacting the polyisocyanate and the polyol is polycarbonate, and (3) claim 1 or This is solved by a coil characterized in that the flat insulated wire according to claim 2 is wound in a line.

[0008]

The water-dispersed varnish of urethane resin used for the insulating film of the flat insulated wire of the present invention decomposes at a low temperature (a temperature lower than 450 ° C.) in a short time, and the decomposed product does not adhere to the conductor. It is a thing. In addition, by using a polycarbonate urethane resin, the heat resistance is equal to or higher than that of the conventional insulating layer.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The conductor may be made of a material used for known electric wires such as copper or aluminum, and its cross-sectional shape is not particularly specified, but it is possible to perform well-arranged winding and to occupy a small area. A conductor having a rectangular cross section is preferable in terms of space saving. The flat shape means that the cross-sectional shape of a plane perpendicular to the longitudinal direction is such that at least the long side of a substantially rectangular shape (including a square shape) is parallel, and has a corner portion (FIG. 1 (a)). The part may be rounded (FIG. 1B) or arcuate (FIG. 1C). The conductor having the above-mentioned cross-sectional shape can be obtained by a known processing method such as wire drawing or a combination of wire drawing and rolling. Regarding the dimensions (thickness, width) of the conductor, the thickness (t) is 0.02 mm to 0.8 mm and the width (w) is 0.2 mm to 1
0 mm is applied.

The water-dispersed varnish used for the insulating film of the flat insulated wire of the present invention may be any one containing at least urethane resin. As the urethane resin, nO = C = N- as the A component. Polyisocyanates represented by RN = C = O (R: alkyl group), polyols represented by nHO-R'-OH (R ': alkyl group) as component B (polyhydroxy compound ), Is used as a raw material and is produced by reacting with a catalyst and a filler.

As the component A, an aromatic, aliphatic or alicyclic organic polyisocyanate which has been conventionally used can be used. , Organic polyisocyanates such as isophorone diisocyanate, hydrogenated xylylene diisocyanate, and tetramethyl xylylene diisocyanate, or compounds thereof.

Component B is a generally known polyether, polyester, polyether ester, polythioether,
Examples thereof include polyols such as polyacetal, polybutadiene, polysiloxane, acrylic, phenolic resin, epoxy, and polycarbonate, and polycarbonate polyol is preferable from the viewpoint of heat resistance and mechanical properties.

The urethane prepolymer obtained by reacting the components A and B with a catalyst and a filler is emulsified to obtain a urethane emulsion. The emulsification includes a forced emulsification type by adding an external activator and a self-emulsification type in which a hydrophilic group or a hydrophilic segment is added to a urethane resin and self-dispersed, and any method may be used. As the hydrophilic segment,
Examples thereof include polyoxyethylene lauryl ether, polyoxyoctyl phenyl ether, sodium lauryl sulfate and sodium dodecylbenzene sulfonate.
The mixing ratio of the A component, the B component and the hydrophilic segment is 50 parts by weight of the B component to 100 parts by weight of the A component.
1000 parts by weight, hydrophilic segment, 1 part by weight to 500
Parts by weight.

The concentration of the water-dispersed varnish in producing the rectangular insulated wire of the present invention is 0.5% by weight to 50% by weight, preferably 1% by weight to 20% by weight. If the concentration of the water-dispersed varnish is lower than 0.5% by weight, the number of pinholes increases and the insulating property becomes insufficient. If the concentration is higher than 50% by weight, good film formation becomes difficult, which is not preferable.

The size of the resin dispersion particles in this water dispersion varnish is usually 1.0 μm or less, preferably 0.5 μm.
If the resin dispersed particles are too large,
It tends to be difficult to form a good thin insulating layer.

The method of coating the outer periphery of the conductor with the insulating layer is as follows.
A known coating technique may be applied, for example, a solution obtained by dissolving the above resin in a solvent is sufficiently dropped on the outer periphery of the conductor, or a dipping method for coating by dipping in a bath of the solution, or the above solution. An electrodeposition method of immersing in a bath to which a charge-imparting agent is added for electrodeposition is exemplified. After that, the solvent is removed and the insulating layer is cured by a drying process and a baking process to form the insulating layer. The thickness of the insulating layer is 0.001 mm to 0.06 m
If it is less than 0.001 mm, the effect as an insulating layer cannot be sufficiently obtained, and if it is more than 0.06 mm, the insulating effect is not significantly improved. As the solvent for dissolving the resin described above, a known solvent may be applied, for example, in the dipping method, cresol, toluene, xylene, naphtha, propylene glycol, ethylene glycol, glycerin, dimethyl terephthalate, alcohols, isopropyl cell solf, dimethyl. Formamide (DMF)
Examples of the electrodeposition method include alcohols and water. The electrodeposition method is preferable in that the working process is simple and the dimensional accuracy is well obtained. In that case, the solvent is preferably water because it has a low environmental load and is easy to handle.

The electrodeposition conditions of the present invention include D.I. C. Voltage 5V to 100V, preferably 7V to 30V, and electrodeposition time is 0.01 seconds to 30 seconds, preferably 0.03 seconds to 15
Seconds. Water dispersion varnish temperature during electrodeposition is 5 ° C-40
C., preferably 10 to 35.degree. At that time, D.
C. A. C. It is also possible to superimpose charges.

Subsequent to the electrodeposition step, in the drying step and the baking step of the film (insulating layer) electrodeposited on the outer periphery of the conductor, excess solvent and water in the insulating layer are removed by evaporation. The drying step is generally 40 ° C to 200 ° C, preferably 60 ° C to 150 ° C. A high temperature (150 ° C. to 300 ° C., preferably 200 ° C. to 250 ° C.) is used in the drying process to accelerate the evaporation of the liquid and to make the electrodeposition resin coating on the conductor uniform (smooth) at the same time. Is also good.

The flat insulated wire of the present invention may have a self-fusing layer, an overcoat layer, or the like coated on the outer periphery of the insulating layer in order to facilitate the production of a coil in which the flat insulated wire is wound in a line. . For example, a thermosetting resin having heat resistance (melting point, glass transition point) after curing may be applied to the self-fusing layer, and specific resins include phenol resin, epoxy resin, polyimide resin and the like. Above all, it is preferable to use the polyimide resin because it is possible to easily obtain a low-viscosity solution of a resin solution in a solvent and has high heat resistance and high adhesive strength in a high temperature atmosphere. The coating of the self-bonding layer is a mixture of one or more of phenol resin, epoxy resin, polyimide resin, etc., or a solution obtained by dissolving a resin in which a part of the epoxy resin is changed to phenol resin, in a solvent Or let it drip well on the outer circumference,
The solution is coated by immersing it in a bath of the solution. Then, in a drying step, the solvent is volatilized and removed to form a self-fusion layer. The thickness of the self-bonding layer is preferably 1 to 100 μm, more preferably 5 to 30 μm. If the thickness is less than 1 μm, the insulating layers will be adjacent to each other beyond the self-fusing layer due to the external force acting in the tram winding process, and the self-fusing layer itself will be easily scratched. If it is thicker than 100 μm, the solvent is dried and removed. Even after the step, the self-bonding layer itself tends to exhibit tackiness, which increases the possibility of blocking in the drum winding step or the like, and the time required for the soldering process becomes long. As the solvent for dissolving the resin described above, a known solvent may be applied, for example, cresol, toluene,
Xylene, MEK, acetone, DMF, etc. can be applied.

A method of manufacturing a coil using the above-described flat insulated wire will be described below. As described above, the rectangular insulated electric wire coated with an insulating layer on the outer periphery of the conductor is wound on a bobbin, and then wound in line by the length required for coil production,
Subsequently, heat treatment is performed to obtain a coil having a sectional shape shown in FIG. 2 (three rows in FIG. 2). The number of turns of the aligned winding may be appropriately adjusted according to the application. Alternatively, the coil may be a coil in which a plurality of coils arranged in a plurality of rows are stacked. The heat treatment conditions at this time may be set as appropriate according to the material used for the insulating layer.

[0021]

EXAMPLES The present invention will be described in detail below with reference to examples. A rectangular insulated electric wire having a width of 1.6 mm and a thickness of 0.13 mm and a rectangular cross-section copper conductor having the insulating layer (thickness 20 μm) shown in Table 1 was produced. In order to evaluate flexibility and insulation characteristics (measure breakdown voltage), φ
An insulated wire having an insulating layer (thickness 20 μm) shown in Table 1 on the outer periphery of a copper conductor having a circular cross section of 1.2 mm was produced.

Example 1 With respect to 100 parts by weight of a diisocyanate-containing group (hexamethylene diisocyanate),
300 parts by weight of polyether polyol (polyethylene glycol) was synthesized, and 15 parts by weight of a hydrophilic segment (carbonyl group: sodium laurate) was further added and emulsified to obtain a self-emulsifying polyurethane emulsion (water dispersion varnish). . Emulsion (varnish concentration: 15
%) Was placed on the inner wall surface of the container, and a DC voltage (20 V) was applied to the rectangular copper conductor to perform electrodeposition coating using the metal rod as a negative electrode. Then, it was heated (100 ° C.) and dried to produce a rectangular insulated electric wire (insulated electric wire). In Table 1, polyurethane is shown as the coating material.

Example 2 With respect to 100 parts by weight of a diisocyanate-containing group (hexamethylene diisocyanate),
300 parts by weight of polycarbonate diol (polyhexamethylene carbonate) was synthesized, and then a rectangular insulated electric wire (insulated electric wire) was produced in the same manner as in Example 1. In Table 1, the coating material is shown as polycarbonate + polyurethane.

COMPARATIVE EXAMPLE 1 An acrylic emulsion (water-dispersed varnish) obtained by copolymerization of methacrylic acid ester and forced emulsification was used as an insulating layer, followed by the same electrodeposition coating and drying steps as in Example 1 to obtain a rectangular insulated wire. (Insulated wire) was produced. In Table 1, acrylic is shown as the coating material.

(Comparative Example 2) A polyester emulsion (water-dispersed varnish) obtained by introducing a hydrophilic group into a polyester resin and emulsifying the same was used as an insulating layer in the same manner as in Example 1 through the electrodeposition coating and drying steps to obtain a rectangular insulated wire. (Insulated wire) was produced. In Table 1, polyester is shown as the coating material.

COMPARATIVE EXAMPLE 3 An epoxy emulsion (water-dispersed varnish) obtained by forcibly emulsifying an epoxy resin with a surfactant was used as an insulating layer through the same electrodeposition coating and drying steps as in Example 1 to obtain a rectangular insulated wire. (Insulated wire) was produced.
In Table 1, epoxy is shown as the coating material.

[0027]

[Table 1]

The following evaluations were performed using the samples in Table 1. (Soldering treatment characteristics) The ends of the rectangular insulated wires of the examples and comparative examples were immersed in a solder bath set to a predetermined temperature for a predetermined time, and when the wires were pulled up from the solder bath, it was visually checked whether solder was attached to the ends. The following evaluations were performed.
The case where the solder was uniformly adhered over the entire immersion area was evaluated as ◯. When the solder adhered but the adhered length was shorter than the length of the dipped portion, it was evaluated as Δ. Solder adheres only to the tip of the immersion part. Alternatively, the case where no solder was attached was evaluated as x. (Flexible) An insulated electric wire coated with a copper conductor having a circular cross section by electrodeposition (insulated electric wire coated with a 20 μm diameter insulating layer (Example, Comparative Example) on a copper conductor having a diameter of 1.2 mm) was applied to its own diameter 10 times. The surface was wound, and the surface was observed with a magnifying glass (magnification: 50 times), and the presence or absence of cracks was confirmed. When no crack was confirmed, it was evaluated as ◯, and when crack was confirmed, it was evaluated as ×. (Insulation characteristics (breakdown voltage)) Insulated electric wire coated with copper conductor with circular cross section by electrodeposition (diameter 1.2mm copper conductor 20μm
Insulated wire coated with the insulating layer of (Example, Comparative Example),
According to JIS C 3003, two or more pieces are set. Each line was connected to an AC voltage generator to raise the voltage and short-circuited voltage was defined as the breakdown voltage. (Heat resistance (temperature index)) The temperature index was measured according to JIS C 3003. In the present invention, the temperature index = continuous use temperature.

[0029]

According to the flat insulated wire of the present invention, it is possible to provide a flat insulated wire having good soldering characteristics.
Furthermore, it has become possible to provide a flat insulated wire having flexibility, insulation properties, and heat resistance equal to or higher than those of conventional ones, and having good soldering properties.

[Brief description of drawings]

FIG. 1 is a diagram showing an example of a cross-sectional shape of a rectangular wire used in the present invention.

FIG. 2 is a diagram showing a coil formed by aligning and winding a rectangular insulated wire of the present invention and a cross section thereof.

[Explanation of symbols]

1 Flat conductor 2 Coil in which the rectangular insulated wire of the present invention is wound in a line 3 insulating layers

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Daizo Yamamoto             663 Minoshima, Arita-shi, Wakayama Mitsubishi Electric Works             Minoshima Co., Ltd.

Claims (3)

[Claims] 1. A rectangular insulated wire in which an insulating layer is formed by electrodeposition of a water-dispersed resin varnish on the outer circumference of a conductor having a rectangular cross section, wherein the water-dispersed resin varnish is reacted with at least polyisocyanates and polyols. A rectangular insulated wire characterized by containing a urethane resin formed by 2. The rectangular insulated wire according to claim 1, wherein the polyol of the urethane resin obtained by reacting the polyisocyanate and the polyol is polycarbonate. 3. A coil comprising the flat insulated wire according to claim 1 or 2 wound in an array.