JPH0620527A - Heat-resistive insulated electric wire - Google Patents

Abstract

PURPOSE:To provide a heat-resistive insulated electric wire which can be used under a temperature environment at 400 deg.C or higher without deterioration of the initial excellent dielectric breakdown voltage due to baking after coiling. CONSTITUTION:An applied-and-baked layer of a paint comprising 100 parts by weight of a bolosiloxane resin solution (N-methyl-2-pyroridon 62.5 weight percent solution of a bolosiloxane resin) and 16 parts by weight of magnesium oxide, which is mixed and dispersed in such a way that the particle size distribution curve of the magnesium oxide has two major peaks at 0.7-1.0mum particle size and at 2.5-4.0mum particle size, is provided on a conductor. An applied-and- baked layer of a polyester resin varnish is provided thereon.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat-resistant insulated electric wire obtained by coating and baking an inorganic polymer-based coating material obtained by mixing and dispersing an inorganic filler with an inorganic polymer.

[0002]

2. Description of the Related Art Conventionally known heat-resistant insulated wires include heat-resistant enameled wires such as polyimide wires, polyamide-imide wires and polyester-imide wires.

However, in all of these, since the insulating coating is made of an organic substance, it decomposes at a temperature of about 400 ° C., and the highest usable temperature is about 240 ° C. even for the highest polyimide wire.

On the other hand, in the case of an insulated wire which has been developed in recent years and has a coating film formed by applying a coating material using a borosiloxane resin on a conductor and baking it at a high temperature, the coating film may peel even at a temperature of 400 ° C. or higher. It is attracting attention because it can be used without using it.

However, this insulated wire has a problem in that when it is fired after coiling, the coating film becomes very porous and the dielectric breakdown voltage drops below the initial value.

[0006]

Thus, the insulated wire in which the paint using the borosiloxane resin developed in recent years is applied and baked on the conductor can be used even in a temperature environment of 400 ° C. or higher. There was a problem that the dielectric breakdown voltage was lowered from the initial value by the subsequent firing.

The present invention has been made in order to solve such a conventional problem. It can be used in a temperature environment of 400 ° C. or higher, and the initial excellent dielectric breakdown voltage can be obtained by firing after coil winding. An object is to provide a heat resistant insulated wire that does not deteriorate.

[0008]

The heat-resistant insulated wire of the present invention has an inorganic polymer and an inorganic filler on the conductor, and the particle size distribution curve has two major peaks at a particle size of 0.7 to 1.0 μm and a particle size of 2.5 to 4.0 μm. It is characterized by being provided with a coating and baking layer of an inorganic polymer coating material which is mixed and dispersed so as to form a curve having

The inorganic polymer coating used in the present invention comprises an inorganic polymer, 10 to 40% by weight of the total amount of the particulate inorganic filler having a particle size of about 1 to 10 μm, and an organic solvent.
It is usually mixed with a media type disperser such as a sand mill or an attritor for 3 to 10 hours, and then this mixture and the rest of the particulate inorganic filler are mixed with a high speed rotary disperser such as a mixer or a dissolver. Usually, it can be obtained by stirring and mixing for 0.5 to 1 hour. FIG. 1 shows an example of the particle size distribution curve of the inorganic filler in the inorganic polymer coating material thus obtained. The total amount of the inorganic filler added is preferably in the range of 30 to 75 parts by weight per 100 parts by weight of the polymer component.

Here, examples of the inorganic polymer include polyborosiloxane, polycarbosilane, polysilastyrene, polysilazane, and polytitanocarbosilane.
Of these, use of polyborosiloxane is preferable. In addition,
Polysiloxane (silicone resin) is also an inorganic polymer 1
Although it is a species, it is inferior in heat resistance to other inorganic polymers, so that when used, it is preferably used in combination with other inorganic polymers.

As the inorganic filler, magnesium oxide,
Examples thereof include aluminum oxide, zirconium oxide, titanium oxide, chromium oxide, boron oxide, thorium oxide, silicon oxide, potassium titanate, mica, talc, silicon carbide, titanium carbide, zirconium carbide, titanium nitride and aluminum nitride. These may be used alone or in combination of two or more.

As the organic solvent, xylene, toluene,
Examples thereof include benzene, ethanol, butanol, cellosolves, ketones, N-methyl-2-pyrrolidone, dimethylacetamide, dimethylformamide, dimethyl sulfoxide and phenols. Silicone oil can also be used as a reaction solvent for the polyborosiloxane resin.

In addition to the above-mentioned components, other additives may be added within the range not impairing the effects of the present invention for the purpose of improving and improving the flexibility and hydrolysis resistance of the coating film and the adhesion with the conductor. It may be blended in a conventional manner.

In the present invention, the particle size distribution curve of the inorganic filler in the above coating composition is 0.7 to 1.0 μm and 2.5.
A curve that does not have two major peaks at ~ 4.0 μm,
That is, if any one of the peaks is out of the above range or there is a third, fourth, ... Peak outside the range, the dielectric breakdown voltage after firing is As a result, the effect of the present invention cannot be sufficiently obtained.

The heat-resistant insulated electric wire of the present invention can be obtained by applying the above-mentioned inorganic polymer paint onto a conductor and baking it at about 400 to 600 ° C. This coating baking layer is 10
About 50 μm is suitable.

In the present invention, in order to enhance flexibility and mechanical strength of the coating on the coating / baking layer of this inorganic polymer coating, a thickness of 5 to 9 μm formed by an organic polymer coating having good heat resistance. You may make it provide a coating baking layer of a certain degree. As the organic polymer heat resistant coating, polyester, polyester imide, polyimide, polyamide imide, polyamide, polyimidazopyrrolone, formal,
A paint in which an organic polymer having excellent heat resistance such as polyurethane or epoxy is blended alone or in a mixture can be used.

As the conductor of the present invention, Ni wire, Ag wire, Ni-plated copper wire or Ag-plated copper wire having good heat resistance are preferably used.

[0018]

In the heat-resistant insulated wire of the present invention, the inorganic polymer is provided with an inorganic filler, and the particle size distribution curve has a particle size of 0.7 to 1.
The use of an inorganic polymer-based paint that is mixed and dispersed so as to form a curve having two major peaks at 0 μm and a particle size of 2.5 to 4.0 μm results in a very dense coating and baking layer of the inorganic polymer-based paint on the conductor. It is formed. Therefore, it can be used at a high temperature of 400 ° C. or higher, and has excellent initial dielectric breakdown characteristics even after firing.

[0019]

EXAMPLES Next, examples and comparative examples will be described.

Example 1 100 parts by weight of a borosiloxane resin solution (62.5% by weight solution of borosiloxane resin in N-methyl-2-pyrrolidone) and a total addition amount of 16 parts by weight of particulate magnesium oxide having a particle size of 1 to 10 μm And 10% of the mixture was mixed and stirred with an attritor (referred to as the first disperser in the table) for 5 hours, and then this mixture was put into a mixer, and the remaining magnesium oxide was mixed and stirred for 0.5 hours. , Adjusted the paint. The particle size distribution of magnesium oxide in this paint was as shown in Table 1.

Next, this paint was applied onto 1.0 mmφ Ni-plated copper wire (plating thickness 2.5 μm) using a vertical baking machine with a furnace length of 7 m at a baking temperature of 450 ° C. and a linear speed of 5 m / min. The baking was repeated to form a baked coating film having a thickness of 35 μm, and a polyester resin varnish was applied and baked on the baked coating film by an ordinary method to obtain an insulated electric wire having an insulation thickness of 40 μm. The characteristics of the obtained insulated wire are also shown in Table 1.

Examples 2 and 3 A coating material was prepared in the same manner as in Example 1 except that the amount of magnesium oxide charged to the attritor was 20% or 30% of the total amount added. The particle size distribution of magnesium oxide in each paint is shown in Table 1.

Next, the obtained coating material was applied and baked onto a 1.0 mmφ Ni-plated copper wire under the same conditions as in Example 1 above, and baked.
A baking coating film with a thickness of μm is formed, and a polyester resin varnish is applied and baked on this by an ordinary method to obtain an insulation thickness.
An insulated electric wire of 40 μm was obtained. The characteristics of the obtained insulated wire are also shown in Table 1.

Comparative Example 1 A paint was prepared in the same manner as in Example 1 except that the borosiloxane resin solution and magnesium oxide were mixed and stirred for 0.5 hours only in a mixer without using an attritor. did. The particle size distribution of magnesium oxide in the paint is as shown in Table 1.

Then, the obtained coating material was applied and baked on a 1.0 mmφ Ni-plated copper wire under the same conditions as in Example 1 above, and baked.
A baking coating film with a thickness of μm is formed, and a polyester resin varnish is applied and baked on this by an ordinary method to obtain an insulation thickness.
An insulated electric wire of 40 μm was obtained. The characteristics of the obtained insulated wire are also shown in Table 1.

Comparative Example 2 A coating material was prepared in the same manner as in Example 1 except that the amount of magnesium oxide added to the attritor was 50% of the total amount added. The particle size distribution of magnesium oxide in the paint is as shown in Table 1.

Then, the obtained coating material was applied and baked on a 1.0 mmφ Ni-plated copper wire under the same conditions as in Example 1 above.
A baking coating film with a thickness of μm is formed, and a polyester resin varnish is applied and baked on this by an ordinary method to obtain an insulation thickness.
An insulated electric wire of 40 μm was obtained. The characteristics of the obtained insulated wire are also shown in Table 1.

Comparative Example 3 A coating material was prepared in the same manner as in Example 1 except that the borosiloxane resin solution and magnesium oxide were mixed and stirred only with an attritor for 5 hours. The particle size distribution of magnesium oxide in the paint is as shown in Table 1.

Then, the obtained coating material was applied and baked on a 1.0 mmφ Ni-plated copper wire under the same conditions as in Example 1 above.
A baking coating film with a thickness of μm is formed, and a polyester resin varnish is applied and baked on this by an ordinary method to obtain an insulation thickness.
An insulated electric wire of 40 μm was obtained. The characteristics of the obtained insulated wire are also shown in Table 1.

[0030]

[Table 1]

[0031]

As is apparent from the above examples, in the heat resistant insulated wire of the present invention, the particle size distribution curve has two major peaks on the conductor at particle sizes of 0.7 to 1.0 μm and 2.5 to 4.0 μm. It has a structure with a coating and baking layer of an inorganic polymer paint in which an inorganic filler is mixed and dispersed so that it has a curved line, so it can be used at a high temperature of 400 ° C or more and has a large dielectric breakdown property by firing. It does not decrease.
Moreover, since the paint can be easily prepared and the coating and baking of the paint can be easily performed, the productivity is excellent.

[Brief description of drawings]

FIG. 1 is a graph showing an example of a particle size distribution curve of an inorganic filler in an inorganic polymer coating material used in the present invention.

Claims (1)

[Claims] 1. An inorganic filler is added to an inorganic polymer on a conductor, the particle size distribution curve of which is 0.7 to 1.0 μm and the particle size is 2.5.
A heat-resistant insulated wire comprising a coating / baking layer of an inorganic polymer-based coating material mixed and dispersed so as to form a curve having two major peaks at ˜4.0 μm.