JPH0412407A - Flat insulated wire - Google Patents

Abstract

PURPOSE:To obtain a wire excellent in heat resistance by having a heat-resisting insulating layer, in which an emulsion type electrodeposited varnish of a polymer having a fixed component is baked to a prescribed thickness around a flat conductor. CONSTITUTION:A flat insulated wire can be obtained by baking an emulsion type electrodeposited varnish 5 having an imide group or amide group polymer as a component around the flat conductor 2 to the thickness not exceeding 5mum to be provided with a heatresisting insulating layer 1. Thereby, the superthin film type heatresisting insulating layer 1 having a full thickness can be formed even on a corner part of the flat conductor 2, moreover being excellent so as to have heat resistance not less than 180 to 200 deg.C. Further, this insulating layer 1 has few pin holes also being excellent in insulation.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a rectangular insulated wire having an ultra-thin heat-resistant insulating layer.

BACKGROUND TECHNOLOGY AND PROBLEMS Conventionally, the limit for reducing the thickness of an insulating layer in rectangular insulated wires has been approximately 10μ. This is because in the method of applying varnish to a rectangular conductor that has been formed to the desired thickness in advance, an insulating layer of the required thickness cannot be formed at some of the corners of the rectangular conductor due to the flow of the varnish during application and baking. On the other hand,
In the method of rolling a round conductor with an insulating layer, the voltage resistance and heat shock resistance decrease due to residual stress in the insulating layer, and cracks occur in the insulating layer, making it unusable. It is to become something.

However, as electric equipment becomes lighter and smaller, there is a demand for thinner rectangular insulated wires, and therefore, making the insulating layer ultra-thin is a challenge.

And in that case, the (i
It is also a challenge to ensure that the insulation layer has excellent heat resistance.

Means for Solving the Problems The present inventors have discovered that the above-mentioned problems can be overcome by achieving an ultra-thin film by using a baked layer of an emulsion-type electrodeposited varnish made of a special heat-resistant polymer. It's arrived.

That is, the present invention is characterized in that the rectangular conductor is surrounded by a heat-resistant insulating layer having a thickness of 5 μm or less and made of a baked layer of an emulsion-type electrodeposited varnish containing an imide-based or amide-based polymer as a component. The present invention provides a special square insulated wire.

Functions and Effects By baking an electrodeposited varnish containing an emulsion of imide-based or amide-based polymers, an ultra-thin insulating layer with a sufficient thickness can be created even on a part of the corner of a rectangular conductor that has been pre-prepared to the desired thickness. It is possible to form an ultra-thin insulating layer which has excellent heat resistance, typically having heat resistance of 180 to 200° C. or higher. Furthermore, the formed heat-resistant insulating layer has a pinhole count (JIS C3
003) is as low as 100 pieces/m or less, usually 70 pieces/m or less, and has excellent insulation properties.

Illustration of the components of the invention FIG. 1 illustrates the rectangular insulated wire of the present invention.

1 is a heat-resistant insulating layer, 2 is a rectangular conductor, 21 is a flat part, 2
2 is a part of the corner.

In the present invention, although not limited thereto, an ultra-thin rectangular conductor is preferably used due to its purpose. As an example, the thickness is 800 μm or less, especially 500 IIm or less,
In particular, those having a width of about 100 μm to 10 μm and a thickness of 10 to 200 μm are mentioned. Aspect ratio is 1/3 to 1/100
The degree is common. The rectangular conductor may be made of any material as long as it has good conductivity. Examples include common electrolytic copper, copper alloys, aluminum, copper-clad aluminum, etc.

The heat-resistant insulating layer provided around the rectangular conductor is formed as a baked layer of an emulsion-type electrodeposition varnish containing an imide-based or amide-based polymer as a component. By using such an emulsion type electrodeposition varnish, the desired ultra-thin film can be achieved. The thickness of the heat-resistant insulating layer to be formed is 5 μm or less, particularly 0.5 to 4.0 μm, especially 0.8 to 3.0 μm.
Ru. In the above-mentioned electrodeposition method, the thickness at the corner part (22) of the rectangular conductor tends to be thicker than that at the flat part (21). This is because the electric field tends to concentrate at the corner part. In this case, the thickness of the heat-resistant insulating layer mentioned above is based on the flat part (21) of the rectangular conductor.In addition, the thickness of the heat-resistant insulating layer at the corner part is usually 1.05 of that in the flat area.
~about IO times.

The rectangular insulated wire of the present invention can be manufactured, for example, by forming a layer of a predetermined thickness of emulsion-type electrodeposited varnish on a rectangular conductor, and then baking the electrodeposited layer. Figure 2 shows an example of the process. In this manufacturing process, first, a rectangular conductor 3 connected to the anode side of a DC power source (not shown) is introduced into an electrodeposited bus 4. Inside the electroplated bus 4,
A predetermined emulsion type electrodeposition varnish 5 is filled,
A cylindrical cathode 6 is arranged. While the rectangular conductor 3 passes through the cylindrical cathode 6, polymer particles in the electrodeposition varnish adhere to it based on the potential difference, forming an electrodeposition layer.

In this case, the emulsion type electrodeposition varnish that can be preferably used is one of the following: a polymer having an imide group with a ring closure rate of 90% or more, a polymer having an amide group, and a polymer having an imide group and an amide group with a ring closure rate of 90% or more. Alternatively, two or more species are dissolved in a solvent, and the solution is added to a polymer-insoluble dispersion medium by a dropwise method or the like. It is made into an emulsion. The aforementioned polymer having an imide group with a ring closure rate of 90% or more refers to a polymer in which 90% or more of the structural units consisting of amic acid groups represented by the following 2 [1] have an imide group structure represented by the formula [11]. It has changed. By using a polymer containing imide groups with a ring closure rate of 90% or more, it is possible to reduce dehydration associated with the ring closure reaction of the amic acid group during the baking of the formation + 1i adhesion layer, and to prevent foaming that causes pinholes, etc. Be able to suppress it.

[3[nl Examples of the above-mentioned polymers include the following.

(1) Polyamideimide having the structure of the following formula (for example, trade name: Torlon 400 (IT; manufactured by Mitsubishi Paper Mills).

(2) Aromatic polyamide having the structure of the following formula (for example, trade name: ATC, manufactured by Mitsubishi Paper Mills).

(3) Polyetherimide having the structure of the following formula (for example, trade name ULTEM 11000: manufactured by GE).

(4) Polyimide having a structure of the following formula (for example, manufactured by Boimide HUpjohn).

However, in the above formulas (1), (2>, (3), and (4), R1 is as follows. R2, R:l is. R4 is a solvent for dissolving the polymer, and N-methyl-
Examples include polar solvents such as 2-pyrrolidone, N,N-dimethylformamide, dimethylsulfoxide, and dimethylacetamide, or mixed solvents thereof.

As the polymer-insoluble dispersion medium, ketones such as acetone, methyl edyl ketone, diethyl ketone, cyclohexanone, and methyl isobutyl ketone are preferably used.

From the viewpoint of stability of the prepared emulsion, the ratio of the solvent to the dispersion medium to be used is set at a weight ratio of 10. /90~5015
0 is appropriate.

When preparing the emulsion, nitrogen-containing compounds such as trimethylamine, triethylamine, tri-n-propylamine, tri-n-butylamine, pyridine, and N-edylpipericine may be added as necessary to increase the chemical equivalent of the electrodeposited polymer. good. The amount added is usually 0.5 to 3 parts by weight per 100 parts by weight of the solvent. Note that the nitrogen-containing compound is preferably added to the polymer solution side.

The concentration of the emulsion type electrodeposition varnish to be prepared is 0.1 to I
O content of 0.3 to 5% by weight is suitable.

If the concentration is less than 0.1% by weight, pinholes may increase and the insulation may be poor, and if it exceeds 10% by weight, it becomes difficult to form a good ultra-thin film. In addition, the particle size in the emulsion is usually 1 μm or less, preferably 0.5p
m or less; if it is too large, the ability to form an ultra-thin film will be poor.

Electrodeposition conditions include, for example, DC voltage: 5 to 100V, 7 to 70V, electrodeposition time: 0.01 to 30 seconds, 0.
．． 03-15 seconds, varnish temperature 5-40°C, especially lO
~35℃, etc. When charging, an alternating current voltage can be superimposed in addition to the direct current voltage.

If necessary, a wiping device such as an air wiper or a roller wiper may be provided at the exit of the electrodeposition bath 4 to remove an excess amount of the electrodeposition varnish.

This makes it even more difficult to foam during baking.
For example, high-speed work of 50 m/min or more can be performed more smoothly.

The rectangular conductor that has passed through the electrodeposition bath 4 is then introduced into a printing device 7. Baking temperature is J angle, 200-700°C1
Among them, the temperature is 250 to 600°C. If foaming or the like is likely to occur during baking, a drying process may be provided as a pre-baking process to perform the drying process in one process. In that case, a baking device or the like is usually used in which the processing temperature is changed to suit the drying process and the baking process. The drying temperature is determined appropriately depending on the solvent used, etc., but is generally 6.
The temperature is 0 to 300°C, particularly 100 to 250°C.

Note that 9 in FIG. 2 indicates the rectangular insulating type 1i18 formed.
This is a winding machine.

The rectangular insulated wire of the present invention may be provided with a layer of self-bonding 11 on top of the heat resistant insulating layer to aid in the operation when it is wound into a coil. The layer of self-fusion 11 can also be provided when the electrodeposited varnish layer is in a semi-cured state. Note that the layer of self-fusion 11 does not need to have insulation properties and does not need to have a uniform thickness, so it may be formed by a coating method such as a dip coating method, or by applying varnish drawing with felt or the like. Good too.

Reference example 1 Aromatic polyamideimide (Torlon 4000T)
100 parts by weight (the same applies hereinafter) was dissolved in 1900 parts of N-methyl-2-pyrodone, and the resulting solution was dropped into 2000 parts of acetone to prepare an electrodeposition varnish consisting of an emulsion with a concentration of 2.5% by weight. I got it.

Reference example 2 Polyetherimide (ULTEM 11000) 10
A solution obtained by dissolving 0 parts in 1900 parts of N~methyl-2-pyrrolidone was added dropwise to 4000 parts of acetone to give
．． An electrodeposited varnish consisting of a 6% by weight emulsion was obtained.

Reference Example 3 A solution obtained by dissolving 100 parts of aromatic polyamideimide (ATU) in 1900 parts of N-methyl-2-pyrrolidone was added to 3000 parts of acetone, and an electrolyte consisting of an emulsion with a concentration of 2.5% by weight was prepared. Got the varnish.

Example 1 A rectangular insulated wire was obtained in a vertical furnace under the following conditions.

Rectangular conductor: Copper foil electrodeposition varnish with thickness 200μm x width 6mm: Reference example 1 Varnish temperature: 20℃ (same below) Cathode: diameter 6cw+% copper cylinder with length 30cm (same below) Distance between electrodes: 3cm (same below) Electrodeposition voltage: DC 15V (same below) Line speed: 5. Om/min Drying temperature: 200°C (same below) Baking temperature: 420°C Example 2 A rectangular insulated wire was obtained according to Example 1 under the following conditions.

Rectangular conductor: A round conductor rolled into a rectangular shape with a thickness of 110 mm.
Aluminum conductor electrodeposition varnish of 0u+X 700 series:
Reference example 2 Linear speed: 20. Om/min Baking temperature=400°C Example 3 A rectangular insulated wire was obtained according to Example 1 under the following conditions.

Rectangular conductor: Copper clad aluminum foil electrodeposited varnish, thickness 500u111 x width 1.5mm Reference example 3 Line speed: 15.0m/min Baking temperature: 400°C Comparative example 1 Solution type polyimide varnish (Nitto Denko) Manufactured by the company, product name:
A rectangular insulated wire was obtained in the same manner as in Example 1, except that a wire (X-600W) was used.

Comparative Example 2 A rectangular insulated wire was obtained in accordance with Example 1, except that a water-dispersed acrylic varnish was used as the electrodeposited varnish and the baking temperature was 380°C.

The following items were investigated for the rectangular insulated wires obtained in the evaluation test examples and comparative examples.

[Thickness of Insulating Layer] The thickness of the insulating layer in the flat part and part of the corner was measured.

[exterior] The appearance of the insulating layer was visually judged.

[Pinhole I The number of pinholes in the insulating layer was investigated in accordance with JISC3003-.

[Softening Temperature 1 The softening temperature of the insulating layer was investigated in accordance with JIS C3003.

[Heat Resistance Temperature I The heat resistance temperature for a life of 20,000 hours was investigated in accordance with ASTM D23011'.

The above results are shown in the table.

*: Most of the rectangular conductor was exposed in a part of the corner, and it was not recognized that an insulating layer was substantially formed. In addition, numerous pinholes were observed in the insulating layer portion formed in the flat part.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of an embodiment, and FIG. 2 is a flowchart of an example of the manufacturing process. 1: Heat-resistant insulating layer 2.3: Rectangular conductor 5: Emulsion type electrodeposition varnish 7 Baking device 8: Rectangular insulated wire Patent applicant Mitsubishi Cable Industries, Ltd. Agent Tsutomu Fujimoto 2nd

Claims (2)

[Claims] 1. A rectangular insulated wire having a heat-resistant insulating layer having a thickness of 5 μm or less and made of a baked layer of an emulsion-type electrodeposited varnish containing an imide-based or amide-based polymer around a rectangular conductor. 2. 2. The rectangular insulated wire according to claim 1, wherein the imide polymer in the emulsion type electrodeposition varnish has a ring closure rate of imide groups of 90% or more.