JPH0660734A - Heat resisting insulating electrical wire and its manufacture and manufacture of heat resisting insulating material - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a heat-resistant insulating material that can withstand continuous use at a high temperature of 400 ° C or higher, a method for producing an insulated wire, and the realization of such an insulated wire. [Structure] 100 parts by weight of a silicon resin selected from polycarbosilane and polytitanocarbosilane, and 10 to 1
Calcination of a composition comprising 00 parts by weight of polysilazane and 10 to 600 parts by weight of an inorganic filler in ammonia or a mixed gas of ammonia and an inert gas at a temperature sufficient to produce silicon nitride. An insulating material is manufactured by. When manufacturing an insulated wire, the conductor is coated with the composition and post-baked. The insulated electric wire includes a conductor and the insulator manufactured as described above.

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 wire, a method for producing the same, and a method for producing a heat-resistant insulating material. Particularly, the present invention relates to a heat-resistant insulated wire that can withstand continuous use at a high temperature of 400 ° C. or higher, a method for producing the same, and a method for producing a heat-resistant insulating material.

[0002]

2. Description of the Related Art As heat resistant insulating materials, organic polymers such as polyimide and polyamideimide are used. The maximum operating temperature of these heat-resistant organic polymers is about 250 ° C.

[0003]

However, the polyimide,
Polyamideimide decomposes at 400 ℃ or above
It cannot be used for applications requiring heat resistance above ℃, such as nuclear power generation by fast breeder reactor, fuel cell, geothermal power generation, etc. Although the ceramic insulator is excellent in heat resistance, it has a problem that it lacks in close contact with the metal conductor. For example, when the insulated wire is bent, the insulator separates from the conductor.

An object of the present invention is to realize a heat-resistant insulated wire which has good adhesion between a metal conductor and an insulator and can withstand continuous use at a high temperature of 400 ° C. or higher, and a method for producing the same.

Another object of the present invention is to realize a method for producing a heat-resistant insulating material which has good adhesion to a metal conductor and can withstand continuous use at a high temperature of 400 ° C. or higher.

[0006]

[Means for Solving the Problems]

According to the present invention, in order to realize an insulated electric wire in which the metal conductor and the insulator are in close contact with each other and can withstand continuous use at a high temperature of 400 ° C. or more, the insulator covering the outer periphery of the conductor is
Coated with a composition consisting of 100 parts by weight of a silicon resin selected from polycarbosilane and polytitanocarbosilane, 10 to 100 parts by weight of polysilazane, and 10 to 600 parts by weight of an inorganic filler, ammonia or ammonia. And ceramics formed by firing at a temperature sufficient to generate silicon nitride in a gas flow of a mixed gas of an inert gas and.

According to the present invention, in order to realize a method for producing an insulated wire in which a metal conductor and an insulator are in close contact with each other and can withstand continuous use at a high temperature of 400 ° C. or more, the outer circumference of the conductor is 100 parts by weight of polycarbonate. Coating with a composition comprising a silicon resin selected from silane and polytitanocarbosilane, 10 to 100 parts by weight of polysilazane, and 10 to 600 parts by weight of an inorganic filler, ammonia or ammonia and an inert gas It is manufactured by firing in a gas stream of a mixed gas at a temperature sufficient to generate silicon nitride.

In the present invention, the close contact with the metal conductor is good, and
In order to realize a method for producing a heat resistant insulating material that can withstand continuous use at a high temperature of 00 ° C. or higher, 100 parts by weight of a silicon resin selected from polycarbosilane and polytitanocarbosilane, and 10 to 100 parts by weight of polysilazane. And 10
An insulating material is produced by firing a composition consisting of 600 parts by weight of an inorganic filler in ammonia or a mixture of ammonia and an inert gas at a temperature sufficient to produce silicon nitride.

The polycarbosilane used in the present invention is a polymer having the following structure.

[0011]

[Chemical 1] In the formula, R ¹¹ and R ¹² may be the same or different and each represents a hydrogen atom or an alkyl group. The alkyl group preferably has 1 to 4 carbon atoms, and is, for example, a methyl group. m is a positive integer.

The polytitanocarbosilane used in the present invention is a polymer having the following structure.

[0013]

[Chemical 2] In the formula, R ¹ , R ² and R ³ may be the same or different,
Each represents an alkyl group. Alkyl group has 1 carbon atom
Those of from 1 to 4 are preferable, for example, a methyl group.
n is a positive integer.

The polysilazane used in the present invention is a polymer having the following structure.

[0015]

[Chemical 3] In the formula, R ²¹ and R ²² may be the same or different and each represents a hydrogen atom or an alkyl group. The alkyl group preferably has 1 to 4 carbon atoms, and is, for example, a methyl group. p is a positive integer.

Polysilazane is used in an amount of 10 to 100 parts by weight based on 100 parts by weight of a silicon resin selected from polycarbosilane and polytitanocarbosilane. If it is less than 10 parts by weight, the adhesion with a metal conductor such as a copper wire is not sufficient, and 1
If it exceeds 100 parts by weight, the composition is easily hydrolyzed, and the storage stability of the insulating material is deteriorated.

Examples of the filler include inorganic substances such as alumina, magnesia, zirconia, titania, mica, talc, silica, aluminum silicate, magnesium silicate, zirconium silicate, titanium silicate, calcium silicate, potassium titanate and barium titanate. Oxides such as silicon carbide, titanium carbide, and carbides such as zirconium carbide, such as boron nitride, aluminum nitride, nitrides such as silicon nitride, such as titanium boride,
Boron compounds such as zirconium boride can be used in the form of powder, fibers, flakes, whiskers and the like. Two or more kinds of fillers or fillers having different shapes may be combined.

The filler is added to the mixture of silicone resins before firing, and the amount of addition is 10 parts by weight per 100 parts by weight of silicone resin selected from polycarbosilane and polytitanocarbosilane.
It is appropriate that the amount is not less than 100 parts by weight and not more than 600 parts by weight. If it is less than 10 parts by weight, cracks may occur in the ceramic after firing. If it exceeds 600 parts by weight, molding of the composition becomes difficult, and for example, a uniform thickness cannot be obtained during extrusion coating.

When the heat-resistant insulating material produced by the present invention is used as a covering for electric wires or other molded insulators, a silicon resin composition containing a filler is molded into a desired shape before firing. It is desirable to set it. The molding can be performed by, for example, extrusion, coating or the like. In the case of coating, the coating material is prepared by dispersing or dissolving it in an organic solvent such as benzene, xylene, toluene, hexane, dimethylformamide, dimethylacetamide, N-methylpyrrolidone and mineral spirit. It is usually appropriate to use 10 to 2000 parts by weight of the solvent for 100 parts by weight of the silicone resin. The viscosity of the coating liquid can be adjusted by the blending ratio of the solvent. It is also possible to control the viscosity of the melt during extrusion coating by adding a solvent.

Before the silicon resin composition is fired, it is preferable to carry out an infusibilizing treatment for crosslinking the silicon resin to give it a three-dimensional structure. In particular, when the composition is molded before firing, such as in the production of insulated wires, it is often necessary to perform infusibilization treatment so that the shape formed during firing is not lost.
Thermal oxidation is usually used for the infusibilizing treatment. Thermal oxidation is performed by heating in air at a temperature of around 200 ° C.

The silicon resin composition may be fired in an ammonia gas, but may be fired in a mixed gas of ammonia and an inert gas. The firing is preferably carried out in a gas stream of these gases. As an inert gas, usually nitrogen,
Argon, helium, etc. are used. The firing temperature is set to a temperature sufficient to generate silicon nitride by the reaction between the silicon resin and ammonia, and is actually set to 400 ° C. or higher.

The preparation, molding, infusibilizing treatment, and firing of the composition may be carried out in individual steps or in a continuous continuous step.

The heat-resistant insulating material produced according to the present invention comprises a ceramic mainly obtained from silicon nitride, which is obtained by firing a silicon resin as described above, and an inorganic filler. An insulator made of such an insulating material is polyimide,
It can be used in combination with an insulator made of another synthetic resin such as polyester, and can prevent moisture and prevent damage. The heat resistant insulating material produced by the present invention is useful as an insulating material for electric wires.

In the insulated wire of the present invention and the insulated wire produced by the present invention, as the conductor, any conductor usually used for insulated wires can be used. The insulator is
Heat-resistant insulation composed of a ceramic mainly composed of silicon nitride and an inorganic filler, which is formed by firing a composition composed of the above-mentioned silicon resin and an inorganic filler coated on the outer periphery of a conductor in ammonia gas. Composed of materials. An insulator made of another insulating material (for convenience, referred to as other insulator) between the insulator made of the insulating material (for convenience, referred to as the insulator according to the present invention) and the conductor, for example, siloxane. but it may also exist insulating layer as a main component. Further, the outer circumference of the insulator according to the present invention can be covered with another insulator such as polyimide or polyester to prevent moisture and damage.

[0025]

In the method for producing an insulated wire of the present invention, the outer periphery of the conductor is coated with the composition comprising the above-mentioned combination of the silicon resin and the inorganic filler, and after the infusibilization treatment, ammonia or ammonia and an inert gas are mixed. By firing in a gas flow of mixed gas, a heat-resistant insulating material mainly composed of a ceramic made of silicon nitride and an inorganic filler is formed in a predetermined shape on the outer circumference of the conductor, so that the insulated wire has excellent heat resistance. . When only polycarbosilane or polytitanocarbosilane is used as the silicon resin, the ceramic insulator produced by firing the composition containing the inorganic filler is
Although the adhesion to the metal conductor is poor, the addition of polysilazane in a predetermined ratio improves the adhesion to the metal conductor of the ceramic insulator produced by firing. The inorganic filler prevents cracks caused by shrinkage associated with ceramization during firing. Since the insulator of the insulated wire of the present invention is mainly composed of a ceramic composed of silicon nitride and an inorganic filler, it has excellent heat resistance. Moreover, the adhesion of the insulator to the metal conductor is good.

According to the method for producing a heat-resistant insulating material of the present invention, a silicon resin selected from polycarbosilane and polytitanocarbosilane and polysilazane are mixed with an inorganic filler in ammonia or a mixed gas of ammonia and an inert gas. By firing in an air stream, a nucleophilic reaction between silicon atoms forming the main chain of the silicon resin and unpaired electrons of nitrogen atoms of ammonia forms a ceramic mainly composed of silicon nitride. An insulating material consisting of an agent is obtained, which insulating material has excellent heat resistance. Since polysilazane is added to polycarbosilane or polytitanocarbosilane at a predetermined ratio, the ceramic insulator produced by firing has good adhesion to the metal conductor. The inorganic filler prevents the generation of cracks due to shrinkage associated with the formation of ceramic during firing.

[0027]

EXAMPLES Examples will be shown below for further detailed explanation of the present invention. [Examples 1 to 7] An example of an insulated wire according to the present invention is a ceramic wire produced by firing a composition shown in Table 1 with a copper wire having a nickel plating layer having a thickness of 2 μm and an outer diameter of 0.8 mm. And a heat resistant insulating material composed of an inorganic filler. Polycarbosilane, polytitanocarbosilane, and polysilazane in Table 1 are polymer compounds shown in Table 2, respectively. The aluminum oxide and zirconium oxide used had an average particle diameter of 2 μm and mica had an average particle diameter of 4 μm.

This heat resistant insulating material was manufactured by the following method. The formulation having the composition shown in Table 1 is mixed using a paint shaker to obtain a paint. This paint was applied to a nickel-plated copper wire at a temperature of 200 with a vertical enamel baking machine.
It was applied and baked 10 times at a temperature of 5 ° C. and a linear velocity of 5 m / min. Subsequently, the mixture was heated at a temperature of 200 ° C. for 30 minutes in the air to be infusibilized. Then, it was baked at a temperature of 600 ° C. for 30 minutes in an ammonia gas stream. The thickness of the insulator was in the range of 30 to 60 μm, was uniform in each case, and no crack was observed.

[0029]

[Table 1]

[0030]

[Table 2]

The conductor adhesion and heat resistance of this insulated wire were evaluated by the following methods. (1) Conductor adhesion In accordance with JIS H8666, observe the peeling and swelling of the insulator (after firing). (2) Heat resistance Using an electric furnace, heating in air at a temperature of 500 ° C for 1000 hours, microscopic observation of the shape change of the insulator, especially the presence or absence of cracks, and measurement of volume resistivity before and after heating It was The volume resistivity was measured according to JIS C3005 after applying a DC voltage of 100 V for 1 minute. The results are shown in Table 5 together with the results of Example 7 and Comparative Example.

[Example 7] Insulation was performed in the same manner as in Examples 1 to 6 except that the composition shown in Table 3 (without solvent) was used and the conductor was coated by extrusion coating of a molten resin. Manufactured an electric wire.

[0033]

[Table 3]

The thickness of the insulator was about 30 μm, which was uniform, and no crack was observed. Heat resistance of Examples 1 to 1
Evaluation was made in the same manner as in 6. [Comparative Examples 1 to 5] Insulated electric wires were produced in the same manner as in Examples 1 to 6 except that the compositions shown in Table 4 and the firing atmosphere were used. The firing temperature and time are the same as those of the examples except for the comparative example 5. In Comparative Example 5, the baking temperature was 350 ° C., and the infusibilizing treatment and the subsequent baking were omitted. Comparative Example 5 is a conventional insulated wire using an insulating material obtained by firing polyimide (Pyre ML manufactured by DuPont).

In Comparative Examples 1, 2 and 5, the thickness of the insulator is 3
It was in the range of 0 to 60 μm, was uniform in each case, and no crack was observed. However, in Comparative Example 3 in which the amount of silicon nitride (filler) was reduced outside the range of the present invention, cracking of the insulator occurred, which made it difficult to measure the volume resistivity described later. Further, in Comparative Example 4 in which the amount of silicon nitride was increased outside the range of the present invention, it was shown that the thickness of the insulator was non-uniform and the moldability of the composition before firing was not good. The conductor adhesion and heat resistance of the insulated wire were evaluated in the same manner as in the above-mentioned examples. The results are shown in Table 6.

[0036]

[Table 4] * Only baking at a temperature of 350 ° C.

[0037]

[Table 5]

[0038]

[Table 6]

As shown in Table 5, all of the insulated wires of Examples 1 to 7 (before aging) according to the present invention had good conductor adhesion and showed a high volume resistivity of 10 ¹⁵ ohm · cm or more, 1/3 reduction in volume resistivity after aging at 500 ℃
It has stopped by 0. On the other hand, as shown in Table 6, in Comparative Example 1 in which the amount of polysilazane was 5 parts by weight with respect to 100 parts by weight of polycarbosilane, the conductor adhesion was poor. Comparative Examples 2 and 4 are the same as Comparative Example 1 with respect to the decrease in volume resistivity and volume resistivity after aging. However, in Comparative Example 2 in which the amount of polysilazane was more than 100 parts by weight with respect to 100 parts by weight of polycarbosilane, the storability of the insulator was poor, and the viscosity was significantly reduced after 7 days at room temperature. Comparative Example 4, in which the amount of filler was increased outside the scope of the invention,
As described above, the moldability is poor. In Comparative Example 3 in which the amount of the filler was reduced outside the range of the present invention, it was difficult to measure the volume resistivity due to the cracking of the insulator.

In Comparative Example 5 produced by the conventional method of firing polyimide in air, the volume resistivity before aging was high, but the deterioration after aging at 500 ° C. was extremely high.
It becomes impossible to measure. This indicates that the film formed by baking polyimide is easily decomposed at a high temperature of 400 ° C. or higher.

From the above Examples and Comparative Examples, the insulating material and the insulated wire produced according to the present invention show excellent heat resistance that can withstand a temperature of 500 ° C. for 1000 hours at any point in terms of shape and volume resistivity. It is understood that the conductor adhesion is also good.

[0042]

INDUSTRIAL APPLICABILITY The insulated wire of the present invention has excellent heat resistance capable of withstanding a temperature of 400 ° C. or higher for at least 1000 hours, and has good adhesion between a conductor and an insulator. According to the method for producing an insulated electric wire of the present invention, it is possible to produce an insulated electric wire that withstands a temperature of 400 ° C. or higher, has the excellent heat resistance as described above, and has good adhesion between a conductor and an insulator. According to the method for producing a heat resistant insulating material of the present invention, it is possible to produce an insulating material having excellent heat resistance and withstanding good conductor adhesion, which can withstand a temperature of 400 ° C. or higher for at least 1000 hours.

Claims (3)

[Claims] 1. An insulated wire having an insulator on the outer circumference of a conductor, wherein the insulator comprises 100 parts by weight of a silicon resin selected from polycarbosilane and polytitanocarbosilane.
Formed by firing a composition consisting of ˜100 parts by weight of polysilazane and 10 to 600 parts by weight of an inorganic filler in ammonia or a mixed gas of ammonia and an inert gas at a temperature at which silicon nitride is produced. Heat-resistant insulated electric wire, characterized in that it is made of a sintered ceramic. 2. A method for producing an insulated wire by coating the outer circumference of a conductor with an insulator, wherein the outer circumference of the conductor is 100 parts by weight of a silicon resin selected from polycarbosilane and polytitanocarbosilane.
˜100 parts by weight of polysilazane and 10 to 600 parts by weight of a composition of an inorganic filler are coated and infusibilized by thermal oxidation. In a mixed gas of ammonia or ammonia and an inert gas, silicon nitride A method for producing a heat-resistant insulated wire, comprising firing at a temperature at which it is produced to form the insulator. 3. A silicon resin selected from 100 parts by weight of polycarbosilane and polytitanocarbosilane, and 10.
A composition comprising ˜100 parts by weight of polysilazane and 10 to 600 parts by weight of an inorganic filler is fired in ammonia or a mixed gas of ammonia and an inert gas at a temperature at which silicon nitride is produced, and the firing is performed. The method for producing a heat-resistant insulating material according to claim 1, wherein is performed in the gas stream of the ammonia or the mixed gas after the composition is infusibilized by thermal oxidation.