JPS62206706A - Manufacture of insulated wire and heat resistant insulated coil using the 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 "Field of Industrial Application" The present invention relates to a method for manufacturing a heat-resistant insulated coil with good heat resistance that can be used in a high-temperature atmosphere, and an insulated wire used therein.

"Conventional technology and its problems" Conventionally, in order to manufacture heat-resistant insulated coils used in such high-temperature atmospheres, an inorganic insulating material such as glass frit is coated on the conductor, and this is heated to form a glass There is a method in which an insulated wire is formed by forming a high-quality insulating layer, and the insulated wire is wound into a coil.

However, since this material lacks flexibility, there are problems such as cracks in the insulating layer or peeling of the insulating layer when coiling it, and also because the thermal expansion coefficients of the conductor and the insulating layer are different. There was a problem in that strain was accumulated in the insulating layer due to heat shock, etc., and the insulating layer was likely to peel off.

In order to improve this problem, inorganic fibers such as glass fibers are fixed onto the conductor using a binder resin, then heated to harden the binder resin to form an insulated wire, which is then wrapped around a bobbin, etc. There is a known method in which the binder resin is decomposed and disappeared by heating to a high temperature in the air, leaving only inorganic fibers, almost eliminating the adhesion between the conductor and the inorganic fibers, and providing sufficient heat resistance. There is.

However, in this method of manufacturing heat-resistant insulated coils, the conductor and bobbin are oxidized at the same time when the binder resin is thermally decomposed in the air, so the conductor and bobbin are made of materials with good oxidation resistance. However, there was a disadvantage that the materials used were limited. In addition, since the conductor and inorganic fibers are not bonded together, if a large diameter conductor or hard conductor is used, the inorganic fibers may be rubbed due to the difference in thermal expansion coefficient between the conductor and the inorganic fibers. , they had the disadvantage that they could be pulled and cut, causing them to fall apart and causing short circuits between lines.

``Means for Solving the Problems'' Therefore, in this invention, inorganic particles mainly composed of glass frit (including glass frit or a mixture of glass frit and high melting point inorganic particles) are coated on the conductor. ) and a soluble binder resin, and a second insulating layer consisting of an inorganic fiber and a soluble binder resin.
An insulated wire is provided by providing an insulating layer, this is wound to form a coil, and this coil is immersed in a good solvent for a soluble binder resin to dissolve and remove the soluble binder resin of the first insulating layer and the second insulating layer. The above-mentioned problem was solved by firing the first insulating layer by heating it to a temperature higher than the softening temperature of the glass frit in a non-oxidizing atmosphere.

FIG. 1 shows an example of an insulated wire according to the present invention, and the reference numeral l in the figure represents a conductor. The conductor l is not particularly limited, and is particularly preferably made of a material with poor oxidation resistance at high temperatures, such as copper, copper alloy, or superconducting wire whose surface is coated with these metals. The diameter of the conductor l is 0.05~
Although the length is about 5 mm, it is not limited to this.

A first insulating layer 2 is provided on the surface of the conductor l. This first insulating layer 2 is made of inorganic particles whose main component is glass frit and a soluble binder resin.
100 parts by weight of inorganic particles and 0.5 parts by weight of soluble binder resin
~70 parts by weight of the composition is dissolved in a good solvent for the soluble binder resin to form a slurry, and this slurry is applied to the conductor l and heated below the curing temperature of the soluble binder resin to remove the good solvent. It is obtained by volatilization.

The thickness of this first insulating layer 2 is 100 μm or less. 1
If the thickness exceeds 00 μm, distortion will accumulate in the insulating layer 2 due to heat shock after firing, and peeling will easily occur.

Glass frit accounts for 35% by volume of inorganic particles.
Those containing the above are preferable, and inorganic particles other than glass frit include alumina, silica, zirconia,
Those containing high melting point inorganic substances such as magnesia and titania, and bonding metal oxides such as iron, nickel, cobalt, copper, manganese, and antimony are used. Also,
The glass frit is preferably one having the following composition and a softening flow temperature of about 600 to 700°C, although it varies somewhat depending on the purpose of use, temperature, etc.

A Pb0 50-85% (weight%) 82
03 3-9% 5iOz 1-4% Zn0 4-15% B PbO50-85% 8203 3-9% SiO22-15% A1.03 1-8% ZrO32-10% CPbO50-80% 8203 2-9% 5iOz 1 to 8% ALO30, 5 to 4% ZnO15 to 28% If this glass frit is less than 35% by volume, the adhesion to the conductor of the first insulator 2 will decrease, and the adhesion between high melting point inorganic substances and gold layer oxides will decrease. This is disadvantageous due to the lack of binding force.

In addition, the soluble binder resin may be any resin as long as it is easily soluble in water and organic solvents.
Resins that easily decompose and disappear as monomers even if a small amount remains, such as methacrylic acid ester polymers, acrylic acid ester polymers, and copolymers thereof, polyethylene that dissolves in both water and organic solvents. Oxide etc. are preferable.

The blending amount of this soluble binder resin is 10 inorganic particles.
It is about 0.5 to 70 parts by weight relative to 0 parts by weight, and it is better to use as little as possible.

Further, as the above-mentioned good solvent, water, ketones, esters, alcohols, hydrocarbons, halogenated hydrocarbons, etc. are appropriately selected in combination with the soluble binder resin.

The concentration of solids (inorganic particles and soluble binder resin) in a slurry consisting of inorganic particles, soluble binder resin, and good solvent is about 50 to 80%, and is determined by its viscosity.

Heating for removing a good solvent is carried out in a temperature range above the solvent vaporization temperature and below the soluble binder resin curing temperature, and in the case of thermoplastic resins, it is usually carried out at 100 to 1500 C, and the time may be about 1 to 10 hours.

A second insulating layer 3 is provided on the surface of such a first insulating layer 2. This second insulating layer 3 is made of inorganic fibers as a conductor.
A resin solution consisting of the soluble binder resin and its good solvent is coated and impregnated while being wound spirally on top of the inorganic fibers, and heated at a temperature below the curing temperature of the soluble binder resin to solidify the inorganic fibers and fix them to the first insulating layer 2. It is something that As the inorganic fibers, single fibers such as electrical glass fibers, alumina fibers, zirconia fibers, and silica fibers, or twisted threads, drawn threads, and woven tapes made of these fibers are used. Further, as the soluble binder resin, it is preferable to use the same resin as that used for the first insulating layer 2, but it does not necessarily have to be the same resin. This resin liquid has these resins dissolved at a concentration of 0.
About 5 to 20% by weight is used. In addition, the heating temperature for solvent removal only needs to be the temperature at which the water and solvent volatilize, and if a thermosetting resin is used as the soluble binder resin, it must be kept at a temperature lower than its crosslinking temperature. . In addition, when thermoplastic resin is used, 100 to 1
Approximately 508C is sufficient.

The thickness of this second insulating layer 3 is usually about 5 to 500 μm. Furthermore, the proportion of inorganic fibers in the second insulating layer 3 is
It is preferable that the weight ratio is 60 to 99.5%, and that the amount of soluble binder resin is as small as possible.

A lubricating layer may be provided on the second insulating layer 3 if necessary. The purpose of this lubricating layer is to improve surface slippage and workability when coiling the insulated wire, and is formed by applying a soluble wax.

Next, a method of manufacturing a heat-resistant insulated coil using such an insulated wire 4 will be described.

First, an insulated wire 4 is wound around a bobbin 5 as shown in FIG. 2 to form a coil 6. Next, this coil 6 is immersed in a good solvent for the soluble binder resin to dissolve and remove the soluble binder resin. If the insulated wire 4 is coated with a lubricant layer, the lubricant layer is removed by immersing it in a solvent that dissolves the lubricant forming the lubricant layer. If the lubricant and soluble binder resin are soluble in the same solvent, they can be dissolved and removed at the same time.

1. as necessary. These solvents may be heated to about 60 to 70°C to promote dissolution of the resin. When specifically dissolving the soluble binder resin, it is preferable to change the solvent several times.

By this solvent immersion, the soluble binder resin of the first insulating layer 2 and the second insulating layer 3 of the insulated wire 4 is dissolved and removed, and the first insulating layer 2 is made only of inorganic particles, and the second insulating layer 3 is made only of inorganic fibers. It is formed from an inorganic material with good heat resistance. In addition, soluble binder resin is 0.02%
Even if it remains unremoved, it will be thermally decomposed and removed during the next step of heating and firing, so that it will not have much of an adverse effect. Next, this coil 6 is placed in a non-oxidizing atmosphere such as an inert atmosphere or a vacuum inert atmosphere, and heated to a temperature equal to or higher than the softening and flow temperature of the glass frit of the first insulating layer 2. By this heating, the glass frit melts and adheres to the conductor 1, binds and holds high-melting point inorganic substances and metal oxide particles, and also partially adheres to the inorganic fibers of the second insulating layer 3. , the second insulating layer 3 is indirectly joined to the conductor I.

The heat-resistant insulated coil 6 thus obtained is used at high temperatures in an inert gas atmosphere or vacuum atmosphere.

[Function] In such an insulated wire 4, the inorganic particles and inorganic fibers that do not stick to the conductor I are fixed to the conductor I using a soluble binder resin, so that they are easily attached to the conductor I during processing such as coil winding. The first and second insulating layers 2.3 do not peel off from the conductor 1, and exhibit good workability.

In addition, in this method of manufacturing the heat-resistant insulated coil 6, since the soluble binder resin of the first insulating layer 2 and the second insulating layer 3 is dissolved and removed using a good solvent thereof, it is necessary to remove the soluble binder resin. This eliminates the need for heat treatment, and the conductor 1 and hobbin 6 made of materials with poor oxidation resistance, such as copper, copper alloy, and iron, can be used.

Furthermore, since the heat-resistant insulated coil 5 thus obtained has the entire surface of the conductor 1 made of an insulator made of an inorganic material, its heat resistance is extremely high. Also, conductor 1
Glass or an insulating material made of glass and inorganic particles is in close contact with the surface, and an insulating material made of inorganic fibers on the outside is partially in contact with the inner glass, which prevents the accumulation of thermal strain. The insulating layer on the conductor 1 will not peel off from the conductor I at least. Furthermore, since the outer inorganic fibers are partially fixed by the inner glass, they will not fall apart even if the inorganic fibers are rubbed and cut due to the difference in expansion and contraction with the conductor l due to the difference in thermal expansion coefficient. Therefore, there is no possibility of partial short circuits between wires, and the insulation voltage increases because the thickness of the insulator becomes thicker. Coated.

a Glass frit (softening point 700°C) 65 parts by weight b Alumina 35 parts by weight C Copolymer consisting of 50 parts normal butyl methacrylate and 50 parts isobutyl acrylate (glass transition temperature 40°
C) 35 parts by weight d Toluene 50
Part by weight was then dried at about 150°C to volatilize the toluene and form a first insulating layer with a thickness of 30 μI.

While glass fibers having a diameter of 7 μm are tightly wound in a spiral shape on this first insulating layer, a resin solution consisting of 35 parts by weight of the above-mentioned copolymer and 50 parts by weight of toluene is applied and impregnated at about 150°C. to volatilize the toluene and 100μ
A second insulating layer of m was provided to obtain an insulated wire.

Next, this insulated wire has a body diameter of 50 mm and an inner width of 150 mm.
A coil was created by winding the IO layer with a pie filer around a ceramic-coated metal bobbin.

This coil was immersed in dichloromethane, which is a good solvent for acrylate copolymer, and when about two to three layers of resin of the coil were dissolved, the acrylate copolymer was dissolved and removed by replacing it with fresh dichloromethane. moreover,
This coil was heated at 700° C. for 10.5 hours in a nitrogen atmosphere to obtain a heat-resistant insulated coil having a porous inorganic layer on the conductor and a glass fiber layer partially adhered thereto.

When the insulation resistance value and dielectric breakdown voltage between the wires of this heat-resistant insulated coil at high temperatures were measured in a nitrogen atmosphere, the results shown in the attached table were obtained.

[Effects of the Invention] As explained above, the insulated wire of the present invention has a first insulating layer made of inorganic particles mainly composed of glass frit and a soluble binder resin, and a first insulating layer made of inorganic fibers and a soluble binder resin on a conductor. Since two insulating layers are provided, inorganic particles and inorganic fibers that do not stick to the conductor are fixed to the conductor using a soluble binder resin, so the first and second insulating layers are used during processing such as coil winding. The insulating layer does not peel off from the conductor and exhibits good workability. Further, the method for manufacturing a heat-resistant insulated coil of the present invention includes a first MA edge layer made of inorganic particles mainly composed of glass frit and a soluble binder resin, and a second insulating layer made of inorganic fibers and a soluble binder resin on a conductor. The provided insulated wire is wound to form a coil, this coil is immersed in a good solvent of soluble binder resin, and after dissolving and removing the soluble binder resin of the first and second insulating layers, it is heated in a non-oxidizing atmosphere. Heat the glass frit to a temperature higher than the softening point II! ! ! Since the edge layer is fired, there is no need for heat treatment in an oxidizing atmosphere to decompose and remove the binder resin, so conductors and bobbins made of materials with poor heat resistance can be used. In addition, even if a large diameter conductor is used, the inorganic fibers will not be cut and broken apart due to thermal distortion caused by rapid cooling from high temperatures, causing local short circuits between wires, and the insulation layer can be thickened, so the dielectric strength can be increased. This has advantages such as the ability to obtain a heat-resistant insulated coil 5 with a high value.

[Brief explanation of drawings]

FIG. 1 is a schematic cross-sectional view showing an example of an insulated wire of the present invention, and FIG. 2 is a partial cross-sectional view showing an example of a heat-resistant insulated coil obtained by the method of manufacturing a heat-resistant insulated coil of the present invention. l...Conductor, 2...First insulating layer 3...Second insulating layer 6...Coil

Claims (2)

[Claims] (1) A first insulating layer made of inorganic particles mainly composed of glass frit and a soluble binder resin and a second insulating layer made of inorganic fibers and a soluble binder resin are provided on the conductor. Insulated wire. (2) Winding an insulated wire on a conductor, which has a first insulating layer made of inorganic particles mainly composed of glass frit and a soluble binder resin, and a second insulating layer made of inorganic fibers and a soluble binder resin. This coil is immersed in a good solvent of soluble binder resin to dissolve and remove the soluble binder resin of the first and second insulating layers, and then heated to a temperature higher than the softening temperature of the glass frit in a non-oxidizing atmosphere. 1. A method for manufacturing a heat-resistant insulated coil, which comprises baking the first insulating layer.