JPH02123618A - Heat resistant insulated electric wire - Google Patents

Abstract

PURPOSE:To obtain the fine heat resistant insulated electric wire by coating the metal alkoxide-type paint on a conductor having the fine conductivity, and hydrolyzing or pyrolyzing the metal alkoxide to form the metal oxide material layer rich in the heat resistance and the insulationability and having the fine adhesion on the conductor. CONSTITUTION:The Ni plating copper wire having the fine conductivity is previously deoxidized by the sulfic acid, the nitric acid, etc., and is washed by the water and is then dried. After completing the pretreatment, the Ni plating copper wire is dipped in the alkoxide-type paint and is passed through it, and the process of passing and heating with the predetermined temperature during the predetermined time after the passing is repeated so as to form the film on the surface of the copper wire. Next, this film is dried with the predetermined temperature during the predetermined time, and by the reaction of the hydrolysis and the pyrolysis progressing during that time, the heat resistant insulated electric wire having the metal oxide material layer with the fine insulation pressure resistance and the flexibility on the surface of the copper wire is obtained. This electric wire has fine resistance to the thermal deterioration and the generation of the crazing, etc., in the insulating film under the condition of the high temperature is eliminated.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a heat-resistant insulated wire having excellent resistance to thermal deterioration.

(Prior technology) Magnet wires, transformer coils Insulated wires used as winding wires for motor coils, etc., are coated with an insulating face in which organic resins such as formal, nylon, polyurethane, and polyester are dissolved in a solvent on the surface of copper wire. Enamelled wire made by coating and baking is widely used.

Furthermore, as insulated wires for signal cables, vinyl wires in which a copper wire is coated with vinyl chloride resin or the like by injection molding are commonly used.

[Problem to be solved by the invention]

However, with the recent demand for smaller and lighter electrical equipment 2 communication equipment, the temperature inside the equipment increases, so there is a strong desire to improve the heat resistance of the insulated wires used within the equipment.

Conventional heat-resistant insulated wires are generally made by coating and baking a polyimide enamel paint on the surface of a copper wire, which has the highest heat resistance among the enamel paints used industrially. However, polyimide is essentially carbon,
Since it is an organic substance with skeletons of hydrogen, oxygen, and nitrogen,
Heat resistance is not sufficient at high temperatures of 250°C or higher.

Ceramic enamelled wire made of 100% inorganic material has also been proposed in order to have heat resistance of about 300°C, but it has not been put into practical use because its flexibility and dielectric breakdown voltage characteristics are significantly inferior. not present.

In addition, as a ceramic enameled wire that retains its flexibility only during the @ wire work of electrical equipment coils, for example, an inorganic powder insulating material such as enamel frit, which can be converted to ceramic at high temperatures, is added to an organic material binder such as silicone paint. There is also ceramic conversion enamelled wire, which is made by blending, applying the blended paint to the surface of the copper wire, and baking it, but this wire is heated at 400'C to 800'C after finishing the coil winding work.
While incinerating the organic material binder at a high temperature of 'C,
There is the hassle of having to convert the inorganic powder insulation material to ceramic.

In addition, in order to eliminate the trouble of performing ceramic conversion after the winding work is completed, a mixture of an organic material binder and a metal oxide powder insulating material such as aluminum oxide or aluminum hydroxide is applied onto the conductor. , enamelled wires that are baked to form a ceramic layer have also been developed;
In this case, the adhesiveness of the binder decreases at high temperatures and the ceramic layer becomes brittle, so cracks in the ceramic layer occur due to the difference in expansion coefficient between the metal oxide powder and the conductor in the high temperature range of 200°C to 300°C or higher. This has the disadvantage that insulation properties are impaired due to peeling. In addition, in order to improve the brittleness of the ceramic layer, Teflon,
Attempts have also been made to cover and reinforce a resin layer made of polyimide or amide-imide, but in this case, the heat resistance of the enameled wire depends on the heat resistance of the resin layer, so 3.
There was a natural limit to its use at high temperatures of 00°C or higher.

Therefore, the present invention aims to solve the technical problem of providing a ceramic layer on a conductor that does not crack or peel off even at high temperatures of 500°C, and improves the reliability of heat-resistant insulated wires. The purpose is to

[Means to solve the problem]

In order to achieve this objective, the present invention applies a metal alkoxide paint on a conductor with good electrical conductivity, and hydrolyzes or thermally decomposes the metal alkoxide to coat the conductor with high heat resistance and insulation properties. A metal oxide layer with good adhesion is formed.

[Operation] In the present invention, the hydrolysis and thermal decomposition of the metal alkoxides M(OR) and 1 in the metal alkoxide paint applied onto the conductor generally forms metal oxides through the following reaction.

(Hydrolysis) M (OR), 1+, Hz O→ M (OH)I,
+, R(OH) M (OH), l-MO, 1/2 + II/Z
H20 (thermal decomposition) M (OR) ,, → MO, /□+ 77□R(OH
)+Olefin In the thermal decomposition reaction, most of the hydroxyl groups are converted to O by heating at 200° C. for 1 hour or more to form a metal oxide.

〔Example〕

Si-based alkoxide S i (OCz Hs ) a
, CH30H and CH3COOC! Add Hs and stir well, add an acidic aqueous solution that does not cause sufficient hydrolysis, and stir vigorously to cause partial hydrolysis to form OH groups and OCH on St.

Partial hydrolysis Sto! A sol was prepared, and T 1 (OC3Hll) a was added dropwise to the sol while stirring to produce a 5t-0-Ti composite alkoxide.

Then, the nickel-plated copper wire (diameter 1mm+), which is a good conductor, is pre-pickled with a sulfuric acid, nitric acid, or hydrochloric acid solution, washed with water, and dried to complete the pretreatment.
It was immersed in the 5t-O-Ti composite alkoxide paint prepared as described above and allowed to pass through, and after passing,
The step of heating at 0° C. for 10 minutes is repeated several times to form a film with a thickness of 25 μm on the surface of the copper wire.

Next, the coating is dried at 180°C for 10 minutes, and the hydrolysis and thermal decomposition reactions that occur during that time create a heat-resistant metal oxide layer with excellent dielectric strength and flexibility on the surface of the copper wire. Manufactured insulated wire.

The heat-resistant insulation wire produced in this way has a dielectric strength of 10 KV or more, a volume resistivity of io'Ωcm or more, a hardness (pencil) of 5H or more, and a metal oxide layer even when bent to a bending curvature of 6 ms. The insulating film made of copper wire does not peel off from the surface of the copper wire, and even when heated at a high temperature of 500°C, the insulating film does not crack or peel off, and the dielectric strength does not deteriorate at all. Obtained.

Additionally, metal alkoxide paints are more stable than conventional heat-resistant paints mixed with inorganic fillers such as aluminum oxide powder.

Paintability is also extremely good.

In addition, for the above paint, Af, 0 is used as the filler.
3. ZrO! , Fez ol , Crz O,.

Metal oxides such as CoO and Snow, BN, and B.

When at least one type of fine particles or fine fibers such as C, SiC, C, St, or N are mixed in an appropriate proportion, the dielectric strength voltage is further improved.

In addition, the composite alkoxide used in the above paint is Af
An insulating film with excellent adhesion and dielectric strength can be obtained by using alkoxides such as i, Ba, La, Sn, or Sr, or composite alkoxides of these and the above-mentioned St and Ti.

In addition, good conductors include not only nickel-coated copper wire, but also stainless steel and chrome.

Copper wire coated with silver, silver wire, gold wire, platinum wire.

A Cu-Ni alloy wire or the like may also be used. Note that when used in applications where heat resistance conditions are not so severe, a wire body made only of ordinary electrolytic copper may be used as is.

Furthermore, when used for windings such as motor coils that require deformation of strength, the strength of the metal oxide layer is ensured even if it sacrifices some heat resistance against abnormal temperature rises due to overload operation. For this purpose, the outermost layer may be formed of a resin coating having excellent heat resistance, flexibility, and electrical insulation, such as an amide-imide coating.

In addition, we also use glass-based materials that do not affect heat resistance, dielectric strength, or flexibility.
It is also possible to overcoat with a phosphate binder to enhance the reinforcing effect.

[Effects of the Invention] As described above, according to the present invention, even at high temperatures of 500'C or higher, the insulation coating made of a metal oxide layer does not crack or deteriorate its dielectric strength, and the heat resistance is improved. This has the very valuable effect of significantly improving the reliability of insulated wires.

Claims (7)

[Claims] (1) A heat-resistant insulated wire characterized in that a metal alkoxide paint is applied onto a conductor with good conductivity, and a metal oxide layer is formed by hydrolysis or thermal decomposition of the metal alkoxide component. (2) The heat-resistant insulated wire according to claim 1, wherein the metal alkoxide paint is composed of one or more alkoxides. (3) The heat-resistant insulated wire according to claim 1, wherein the metal alkoxide paint is composed of a mixture of ultrafine particles made by hydrolyzing metal alkoxide and one or more alkoxides. . (4) The metal alkoxide paint is composed of a filler consisting of at least one type of fine particles or fine fibers such as metal or other oxides, carbides, nitrides, etc., and one or more alkoxides. A heat-resistant insulated wire according to claim 1. (5) The heat-resistant insulated wire according to claim 1, wherein the conductor with good conductivity is made of copper or a copper-based metal. (6) Heat resistance according to claim 1, wherein the conductor with good conductivity has a structure in which the surface of a filament made of copper or a copper-based metal is coated with nickel, chromium, stainless steel, or silver. Insulated wire. (7) A metal alkoxide paint is applied on a conductor with good conductivity, and a metal oxide layer is formed by hydrolysis or thermal decomposition of the metal alkoxide component, which further improves heat resistance, flexibility, and electrical insulation. A heat-resistant insulated wire characterized by having an outermost layer made of a superior resin.