JPS59163709A - magnet wire - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field) The present invention relates to improvements in magnet wires used in motors, transformers, magnetic coils, and the like.

(Prior art and its problems) Currently, magnet wires use an insulating paint made by dissolving a polymer or prepolymer in an organic solvent, apply this to the conductor by squeezing it with a die or felt, and then baking it in a baking oven multiple times. Manufactured repeatedly. This method uses large amounts of highly toxic organic solvents, so
It causes air pollution, creating a poor working environment, has poor energy efficiency, and cannot be manufactured at high speed due to solvent removal and curing.

Recently, a method of manufacturing magnet wire using extrusion coating has attracted attention as a method of manufacturing magnet wire that does not use any solvent at all and can be manufactured at a manufacturing speed of several hundred meters, and its application to various thermoplastic resins has been proposed. There is.

However, extrusion coated magnet wires have the following drawbacks.

■Extrusion coating is usually done in one coat, so magnet wires manufactured by extrusion coating have electrical properties such as breakdown voltage and pinholes that are significantly inferior to those made using conventional baking methods. Therefore, although it is technically possible to perform extrusion coating multiple times to improve electrical properties, for example, multiple extruders are required.

Furthermore, since it is necessary to apply a thin film, there are problems in terms of equipment and manufacturing technology, making it difficult to implement.

■One of the required characteristics of magnet wire is its adhesion to the conductor.

In the case of extrusion coating, unless the conductor is preheated, the molten resin will not uniformly wet the surface of the conductor, making it impossible to obtain good adhesion between the insulating layer and the conductor.

In order to obtain a magnet wire with good adhesion, it is necessary to preheat the conductor to near the softening point of the extruded resin, which usually requires dielectric heating or electrical heating, which requires a large amount of energy. Particularly when using extruded materials with a high softening point, it is necessary to preheat the conductor to a temperature at which the conductor, such as a copper wire, will discolor. Therefore, it is necessary to preheat the conductor under an inert gas atmosphere to prevent discoloration of the conductor. Not only that, but a large amount of equipment and running costs are required.

The present invention improves the problems of the above-mentioned extrusion coated magnet wire.

(Structure of the Invention) The present invention is a composite comprising a first insulating layer formed by coating and baking an insulating paint on a conductor, and a second insulating layer formed by extrusion coating a composition containing a condensed thermoplastic resin as a main component thereon. This magnet wire has an insulating film, and is characterized in that the first insulating layer coated with an insulating paint and baked has a thickness of 1/1O or less of the total thickness of the composite insulating film.

In the present invention, the insulating paint may be any insulating paint commonly used in the manufacture of magnet wires, such as polyamideimide, polyamideimide varnish, polyesterimide varnish, polyether foam, polyurethane foam, polyvinyl formal varnish, polyvinyl butyral varnish. , polyamide varnish, phenoxy varnish, etc.

These can be used alone (they can also be used as a mixture of two or more types).

In the present invention, a composition containing a condensed thermoplastic resin as a main component refers to a condensed thermoplastic resin itself, or a condensed thermoplastic resin to which crosslinking aids, dyes, pigments, fillers, etc. are added.

Examples of condensation thermoplastic resins include polyethylene terephthalate, polybutylene lenticulate, polyX◇-RX◇
- Polyether resins such as aromatic polyesters represented by 〇几 (R is CH, So, C (CH), etc.), 6-nylon, 6.6-nylon, amide resin, phenoxy resin, polyphenylene oxide, etc. Examples include polyether resin, polysulfone, polysulfone resin such as polyether sulfone, and other polycarbonate resins, polyesteramide resins, polyether ester resins, polyphenylene sulfide resins, polynietian resins, and polyetherimide resins.

Furthermore, when the above-mentioned condensed thermoplastic resins are used in the magnet wire of the present invention, it is also possible to use two or more of them as a blend, or as a multi-layered film formed by extrusion coating separately.

In the present invention, among these, magnet wire binding
From the viewpoint of heat resistance, it is preferable to use a condensed thermoplastic resin having a melting point or flow temperature of 170° C. or higher.

In order to improve the thermal properties of the magnet wire produced according to the present invention, a crosslinking agent such as triallyl isocyanurate, triallyl cyanurate, diallyl terephucurate, diallyl isophthalate, etc. is added, and after extrusion coating, release radiation is irradiated to form a film. It is also possible to cure by crosslinking.

It is also possible to add dyes and pigments for coloring.
Inorganic fillers containing silicon dioxide, calcium oxide, magnesium oxide, calcium carbonate, aluminum oxide, iron oxide, titanium dioxide, etc. as main components may be added to reinforce the film and reduce raw material costs.

In the present invention, an insulating layer is applied and baked on the conductor before extrusion coating with a composition mainly composed of a condensed thermoplastic resin, so there is no need to preheat the conductor during extrusion coating. A magnet wire with excellent adhesion can be obtained, and at the same time, it is also possible to obtain a magnet wire that is superior in electrical properties to extrusion-coated magnet wires that have been proposed in the past. Furthermore, since there is no need to preheat the conductor, there is no need to worry about discoloration of the conductor.

In the present invention, the reason why the thickness of the insulating layer formed by applying and baking the insulating paint is set to 1/10 or less of the total film thickness is that even if the ratio of the insulating layer formed by applying and baking the insulating coating to the total film thickness is 'Ao or less, the effect is sufficient. On the other hand, even if the proportion of the thickness of the insulating layer formed by applying and baking the insulating paint is increased, the effect will not change much, but the advantage of manufacturing the magnet wire by extrusion coating will be enhanced. By only damaging it.

In addition, the insulation film thickness of the magnet wire is at most 50 μm even if it is a large size as specified by JIS etc., and if the film coated with insulation paint and baked is less than iAo of the total film thickness, the number of times the insulation paint is applied and baked is 1. Another advantage is that it can be done in just one session.

In producing the magnet wire of the present invention, the step of applying and curing the insulating material and the step of extrusion coating the composition containing a condensed thermoplastic resin as a main component may be performed consecutively or in separate steps.

Similarly, if the above steps are performed continuously and a composition containing a condensed thermoplastic resin as a main component is coated by extrusion before the insulating material is completely cooled, a magnet wire with even better adhesion can be produced, which is effective. .

The present invention will be explained below with reference to Examples and Comparative Examples, but the present invention is not limited by these Examples.

[Reference example]

Polyester face (Nitto Electric Industry Co., Ltd. Delaco-1, E
220G) on a copper wire with a diameter of 0.7 mm and a furnace length of 9.5 m.

Furnace temperature: 360°C at the top, 820°C at the middle, 260°C at the bottom
Coating and baking was performed once at a linear speed of 15 m/min using a vertical furnace.

The insulation film thickness was about 2 μm.

[Example 1] Polyethylene terephthalate resin (hereinafter PE manufactured by Toyo Keisha)
(abbreviated as T) was extrusion coated using an extruder at an extrusion temperature of 300°C onto the electric wire produced in the reference example without preheating the conductor. The insulation film thickness of the PET extrusion coating was 25 μm. Table 1 shows the properties of this extruded wire.

[Comparative Example 1] A PET resin was extruded and coated on an annealed copper wire of 0.7fl1Mφ using an extruder at an extrusion temperature of 300°C and a conductor preheating temperature of 200°C. The insulation film thickness was 28 μm.

The properties of this extruded wire are shown in Table 1.

[Example 2] A polyether sulfone resin (ICI [hereinafter abbreviated as PES) was extrusion coated onto the electric wire manufactured in Reference Example at an extrusion temperature of 370° C. without preheating the conductor. P.E.
The insulation film thickness of the S extrusion coating was 29 μm.

Table 2 shows the properties of this extruded wire.

[Comparative Examples 2 and 3] PES resin was extruded using an extruder at a temperature of 370°C, a conductor preheating temperature of 300°C (Comparative Example 2), and a conductor preheating temperature of 200°C.
°C (Comparative Example 3), extrusion coating was carried out on an annealed copper wire of 0.711L711φ. The insulation film thickness is 32 μm (comparative example 2), 3
It was 3 μm (Comparative Example 8).

Table 2 shows the properties of this extruded wire.

Table 2 Characteristics of PES-based extruded wire (effects of the invention) As shown in Tables 1 and 2, the electrical characteristics of the magnet wire according to the present invention were greatly improved. In addition, the magnet wire according to the present invention has good adhesion even without preheating the conductor during manufacture, and there is no fear of discoloration of the conductor even when a material with a high softening point is used for the insulating film.

As described above, the magnet wire of the present invention has good electrical properties, and there is no need to preheat the conductor during manufacturing, and its industrial value is extremely large.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a magnet wire showing an example of the present invention. (1) is a conductor, (2) is an insulating layer coated with an insulating material and baked, and (3) is an insulating layer coated by extrusion with a composition whose main component is a condensed thermoplastic resin.

Claims (1)

[Claims] (1) A first insulating layer in which an insulating paint is applied and baked on the conductor;
It has a composite insulating coating consisting of a second insulating layer coated by extrusion with a composition containing a condensed thermoplastic resin as a main component thereon,
A magnet wire characterized in that the first insulating layer is 1/lo or less of the total thickness of the composite insulating film.