JPH03201312A - Heat resistant insulated electric wire - Google Patents

Abstract

PURPOSE:To enable the holding of insulation even at high temperature, by coating a conducting body around with a ceramic layer and an inorganic insulating layer in gel condition. CONSTITUTION:A copper body 11 is coated around with a nickel-plated layer 12, which is coated around with a ceramic layer 13, which is coated around with an insulating layer 14 in gel condition. In this case, the ceramic layer 13 is excellent in close contact with the conducting body and capable of obtaining and holding with the help of the insulation layer 14 in gel condition. The insulating layer 14 can be thickened by containing ceramic particles in gel condition in the layer 14. This enables the holding of insulation even at high temperature and excellence in flexibility, and capable of obtaining a high breakdown voltage.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a heat-resistant insulated wire, and particularly to an insulated wire used in a high-temperature environment.

[Conventional technology] Heat-resistant organic materials such as polyimide and fluororesin have traditionally been used in equipment that requires safety under high temperatures, such as heating equipment and fire alarms, and in environments that are heated to high temperatures such as in automobiles. Insulated wires whose conductors are coated with resin are used.

In addition, conventionally, in cases where particularly high heat resistance is required, insulated wires are made of ceramics with a conductor passed through a tube, or stainless steel alloys filled with fine particles of metal oxide such as magnesium oxide. A so-called alumite electric wire, in which a conductor is passed through a heat-resistant alloy tube, and an alumite electric wire, in which an aluminum alloy wire is anodized, are used.

Furthermore, insulated wires have been proposed in which ceramic films are formed around conductors using materials that can be made into ceramics, such as metal alkoxides and metal organic acid salts.

[Problems to be Solved by the Invention] In the insulated wire in which a conductor is coated with the above-mentioned heat-resistant organic resin, the temperature at which insulation can be maintained is about 3°O°C at most. Therefore, such insulated wires cannot be used in applications that require insulation even at higher temperatures.

On the other hand, the above-mentioned type of insulated wire in which the conductor is passed through a ceramic insulator tube maintains its insulation properties even at high temperatures.
It had the disadvantage of poor flexibility.

Furthermore, the aforementioned Ml cable can maintain its insulation properties even at high temperatures, and is more flexible than the above-mentioned type in which the conductor is passed through the ceramic insulator tube, but it is difficult to bend it with a large curvature. was accompanying.

Moreover, the alumite electric wire described above can maintain insulation properties even at high temperatures, and also has a certain degree of flexibility.

However, since the conductor used in the electric wire is limited to aluminum, the uses of the electric wire are limited.

Furthermore, the aforementioned insulated wires with a ceramic layer formed around the conductor often have a single ceramic layer with a thin layer, and even though they have good flexibility, they have a high dielectric breakdown voltage. The problem was that it was difficult to

Therefore, an object of the present invention is to solve the above problems and provide an insulated wire having the following properties.

(a) Able to maintain insulation properties even at high temperatures.

(b) Excellent flexibility.

(c) A wide variety of conductors can be used.

(d) It has a high dielectric breakdown voltage.

[Means for Solving the Problems] An insulated wire of the present invention includes a conductor, a ceramic layer formed around the conductor, and an insulating layer in a gel state of a ceramic precursor formed around the ceramic layer. It is equipped with

The gel state mentioned here is a type of precursor state that changes into ceramics through heat treatment, which is mainly produced by a sol-gel method, an organic acid salt pyrolysis method, or the like.

For example, the sol solution produced by the sol-gel method is a metal containing an alkoxide group, a hydroxyl group, or a metalloxane bond, which is produced by the hydrolysis reaction and dehydration synthesis reaction of a compound having a hydrolyzable organic group such as a metal alkoxide. Ceramic precursors, which are organic compound polymers,
It contains an organic solvent such as alcohol as a solvent, a metal alkoxide as a raw material, and a small amount of water and a catalyst necessary for the hydrolysis reaction. This sol solution progresses from a liquid state to an agar-like gel state as the metalloxane bonds lengthen as the condensation reaction progresses and the solvent is sold. In this gel state,
It has a structure in which organic substances, water, etc. are retained in the mesh drawn with voids made of metalloxane bonds, and the three-dimensional structure is not yet completed, resulting in a highly flexible state. Further, although heating is not necessary for progressing to a gel state, heating accelerates the progress of the gel state. Gel becomes a state in which almost no organic substances or water are contained in the pores of the transverse network by heating, etc., and becomes what is called a xerogel. Further heating causes condensation of hydroxyl groups, elongation of metalloxane bonds, and the final transforms into ceramics.

In addition, as a wire with better flexibility, there is a heat-resistant insulated wire in which the degree of ceramicization becomes lower as the insulating layer in the gel state is located on the outer side.

Moreover, as a wire having a higher dielectric breakdown voltage, there may be mentioned a heat-resistant insulated wire in which the gel-state insulating layer includes ceramic particles.

Furthermore, a heat-resistant insulated wire in which the ceramic layer is formed by a condensation reaction of a metal alkoxide or a thermal decomposition reaction of a metal organic acid salt has a more homogeneous insulating layer.

Furthermore, if the ceramic particles are mica,
The result is a heat-resistant insulated wire with higher dielectric breakdown voltage and flexibility.

Note that the conductor is not particularly limited as long as it has conductivity. For example, the material may be plated with nickel or the like having excellent high-temperature oxidation resistance, or may be pre-treated or surface-treated to improve the adhesion of the insulating layer.

[Function] The insulated wire of the present invention has an insulating layer of ceramic and gel-like inorganic materials around the conductor, so it maintains its insulation properties even at high temperatures compared to an insulated wire coated with a heat-resistant organic resin. can.

In the insulated wire of the present invention, the thickness of the ceramic layer formed around the conductor is preferably kept at 1 to 10 μm. This is because if the ceramic layer formed around the conductor becomes too thick, the flexibility of the obtained insulated wire will be impaired.

In this invention, an insulated wire with excellent flexibility and high dielectric breakdown voltage is obtained by forming a thick insulating layer in a gel state of a highly flexible ceramic precursor around a ceramic layer. .

Note that if only an insulating layer in the gel state of a ceramic precursor is formed around a conductor, this insulating layer will lose its adhesion to the conductor when exposed to extreme heating conditions, making it unable to maintain high insulation properties. There is a risk that it will disappear. On the other hand, the ceramic layer has excellent adhesion to the conductor, and together with the gel-state insulating layer, can obtain and maintain high insulation properties.

In addition, when forming a gel-state insulating layer, if the layers are stacked several times and the degree of ceramicization is lower on the outside of the layer than on the outside, there will be no sudden structural changes and it will be more effective. An insulated wire with excellent flexibility can be obtained.

Furthermore, by adding ceramic particles to the insulating layer in a gel state, the layer can be made thicker, and an insulated wire having a higher dielectric breakdown voltage can be obtained.

Furthermore, if the ceramic particles are mica,
The dielectric breakdown voltage of the insulated wire can be made higher.

On the other hand, the ceramic layer and/or the insulating layer in a gel state are made of alkylcosides and organic acid salts such as S1% AQ, Zr, Mg, and T1, and a solution of these materials is applied to the conductor and around the ceramic layer. It can be formed by coating and baking.

By forming the insulating layer in this way, a homogeneous layer can be obtained.

[Example] (Example 1) A nickel-clad annealed copper wire with a diameter of 1 mm whose surface was etched was used as a conductor.

After applying a mixed solution of 2 mol% silicon alkoxide, 10 mol% water, 87.92 mol% ethyl alcohol, and 0.08 mol% nitric acid to the aforementioned conductor, the temperature was 500°C.
Baking was carried out for 20 to 30 minutes. By repeating this operation, a ceramic layer containing almost no organic component and having a thickness of 3 μm was formed around the conductor.

Furthermore, a solution consisting of the silicon alkoxide described above, water, ethyl alcohol, nitric acid, and formaldehyde in an amount of 1/10 equivalent to the silicon alkoxide was applied around the ceramic layer, and baked at a temperature of 150° C. for 10 minutes.

In this reaction, the weight loss rate of the reaction system was suppressed to about half that of the ceramic layer forming reaction described above.

As a result, an insulating layer in a gel state with a thickness of 25 μm was obtained.

The insulated wire thus obtained maintained its insulation properties even when kept at a temperature of 600° C. for 30 minutes, and was able to maintain its insulation properties even at high temperatures.

Further, this insulated wire was bent with a curvature of 5 mmR, but the insulation properties were not impaired. Therefore, it can be said that it has excellent flexibility.

Furthermore, when the dielectric breakdown voltage of this insulated wire was measured, it was 600 V or more, indicating that it had a high dielectric breakdown voltage.

FIG. 1 is a cross-sectional view of the obtained insulated wire.

A ceramic layer 13 is formed around a conductor in which a nickel plating layer 12 is formed around copper 11. Furthermore, an insulating layer 1 in a gel state is placed around the ceramic layer] 3.
4 is formed.

(Example 2) A nickel-plated annealed copper wire with a diameter of 2 mm was used as a conductor.

After applying a 20 mol % solution of octanoic acid silicate in toluene to the above-mentioned conductor, baking was performed at a temperature of 500° C. for 30 minutes. By repeating this operation, a thickness of 5μ
A ceramic layer of m was formed around the conductor.

A mixed solution of 7 mol 96 silicon ethoxide, 1 mol % zirconium butoxide, 8 mol % water, and 84 mol % isopropyl alcohol was prepared.

Approximately 0.0 parts per 10 parts of the mixed solution. Three parts of aluminum oxide particles having a size of 3 μm were mixed.

In this way, the solution mixed with aluminum oxide was applied around the conductor described above, and continuously at a temperature of 200°C.
I did the baking. In the manner described above, a gel-state insulating layer containing aluminum oxide particles could be formed around the ceramic layer.

FIG. 2 is a cross-sectional view of the insulated wire obtained as described above.

A ceramic layer 23 is formed around the conductor in which a nickel layer 22 is formed around copper 21 . Furthermore, aluminum oxide particles 24 are placed around the ceramic layer 23.
An insulating layer 25 in a gel state containing .

The insulated wire thus obtained maintained its insulation properties and had good flexibility when subjected to bending with a curvature of 20 mmR.

Further, this insulated wire had a dielectric breakdown voltage of 1200V or more.

Furthermore, regarding this insulated wire, 10
0 hour heat resistance test and 30 at a temperature of 600℃
An overheating test was conducted in which the product was held for several minutes, but the insulation properties were not impaired.

[Effects of the Invention] As explained above, the present invention provides a heat-resistant insulated wire that uses various types of conductors to maintain insulation properties even at high temperatures, has excellent flexibility, and has a high dielectric breakdown voltage. koto power (able to do)

Therefore, this invention has particularly heat resistance and nonflammability, and
This is for insulated wires that require a withstand voltage of approximately 000V.

Furthermore, the present invention can be applied to flexible printed circuits that require heat resistance.

[Brief explanation of drawings]

FIGS. 1 and 2 are cross-sectional views showing an example of the insulated wire of the present invention. In the figure, 11 is copper, 12 is a nickel plating layer, and 13 is a nickel plating layer.
14 is a ceramic layer, 14 is an insulating layer in a gel state, 21 is copper, 22 is a nickel layer, 23 is a ceramic layer, 24 is an aluminum oxide particle, and 25 is an insulating layer in a gel state. Figure 1 11: Copper 12: Nickel plating layer 13: Ceramic layer 14 Insulating layer in Nigel state

Claims (5)

[Claims] (1) A heat-resistant insulated wire comprising: a conductor; a ceramic layer formed around the conductor; and an insulating layer in a gel state of a ceramic precursor formed around the ceramic layer. (2) The insulating layer in a gel state is in a gel state in which the degree of ceramicization becomes lower toward the outside.
The heat-resistant insulated wire described. (3) The heat-resistant insulated wire according to claim 1 or 2, wherein the gel-state insulating layer contains ceramic particles. (4) Claim 1, wherein the ceramic layer and/or the gel-state insulating layer are formed by a condensation reaction of an alkoxide or a thermal decomposition reaction of a metal organic acid salt.
The heat-resistant insulated wire according to any one of items 1 to 3. (5) Claim 3, wherein the ceramic particles are mica.
or the heat-resistant insulated wire described in 4.