JPH07320553A - Heat resisting insulated wire - Google Patents

Abstract

PURPOSE:To provide a heat resisting insulated wire having excellent heat resistance and flexibility by providing an applied baking layer of organic polymer system heat resisting paint, compounding an inorganic filler with a concentration gradient, on an applied baking layer of inorganic polymer paint. CONSTITUTION:A heat resisting insulated wire is constituted by providing an applied baking layer 2 of inorganic polymer paint on a conductor of such as an Ni wire, and by providing an applied baking layer 3 of organic polymer heat resisting paint on the applied baking layer 2. In the applied baking layer 3 of organic polymer heat resisting paint, an organic filler is compound in a manner wherein its concentration is generated high in a side of the applied baking layer 2 of inorganic polymer paint to gradually decrease toward a surface layer side. In this way, excellent heat resistance and flexibility are both provided usable under a temperature environment of 400 deg.C or more, to make capable working coil winding or the like.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention has excellent heat resistance and
The present invention relates to a heat-resistant insulated electric wire having good flexibility.

[0002]

2. Description of the Related Art In recent years, with the reduction in size and weight of motors and transformers, the enameled wire used for them is required to have higher heat resistance.

Polyimide wire, polyamide-imide wire, polyester-imide wire and the like are generally known as enamel wire having excellent heat resistance. However, all of them have a temperature of about 400 ° C. because the insulating coating is made of an organic material. The highest usable temperature was about 240 ° C even with the highest polyimide wire.

Under such circumstances, recently, the main chain such as polyborosiloxane and polytitanosiloxane has Si, T
A so-called inorganic polymer electric wire was developed by coating and baking a paint whose main component is a metal element such as i or B and an inorganic polymer such as O or N. It has been noted that it can be used even in a temperature environment of 400 ° C or higher. ing.

However, this inorganic polymer electric wire is
Although it has excellent heat resistance, it has poor flexibility and is difficult to coil.

Therefore, in order to solve this problem, the baking temperature of the paint is lowered, an organic resin layer such as polyester or polyesterimide is provided on the surface, and after coiling or the like, heating is performed at a high temperature. , The coating film is completely baked. However, in such an electric wire, organic components on the surface are thermally decomposed and desorbed in the firing step after processing, but at that time, cracks are induced in the coating film of the lower layer to obtain desired heat resistance. However, there is a problem in that the insulation characteristics are impaired.

[0007]

As described above, an inorganic polymer electric wire coated and baked with a coating material containing an inorganic polymer such as polyborosiloxane as a main component has a drawback that it is poor in flexibility. For this reason, the paint is baked at a low temperature and an organic resin layer is provided on the surface. However, although the flexibility is improved, the original heat resistance is not obtained and the insulation property is deteriorated. There was a problem.

The present invention has been made in consideration of such a point, and has excellent heat resistance and flexibility which can be used in a temperature environment of 400 ° C. or higher, and can be used for processing such as coil winding. It is an object of the present invention to provide a heat-resistant insulated electric wire that retains its excellent heat resistance afterwards and does not impair the insulating property.

[0009]

Means for Solving the Problems That is, the heat-resistant insulated wire of the present invention is a heat-resistant insulation comprising a conductor and a coating / baking layer of an inorganic polymer-based paint and an organic polymer-based heat-resistant coating / coating layer formed on the conductor in this order. In the electric wire, the organic polymer heat-resistant coating coating baking layer, an inorganic filler is blended with a concentration gradient such that the inorganic polymer coating coating baking layer side is high and gradually decreases toward the surface side. It is characterized by being.

The present invention will be described below with reference to the drawings.

FIG. 1 is a sectional view showing the structure of an embodiment of the heat resistant insulated wire of the present invention.

As shown in FIG. 1, this heat-resistant insulated wire is
An inorganic polymer type coating / baking layer 2 is provided on a conductor 1 such as a Ni wire, and an organic polymer type heat resistant coating / coating layer 3 is provided thereon. Inorganic filler is blended in the coating / baking layer 3 of the organic polymer heat-resistant coating so that the concentration thereof is high on the coating / baking layer 2 side of the inorganic polymer coating and gradually decreases toward the surface side. .

Here, the coating and baking layer 2 of the inorganic polymer paint is used.
The inorganic polymer-based coating material that comprises the inorganic polymer as a main component of the binder, and if necessary, an inorganic filler and other additives are blended appropriately, and these are dissolved or dispersed in an appropriate amount of solvent. It is a thing. Examples of the inorganic polymer include polyborosiloxane, polycarbosilane, polysilastyrene, polysilazane, and polytitanocarbosilane. Among them, polyborosiloxane is preferably used. Polysiloxane (silicone resin) is also one kind of inorganic polymer, but it is inferior in heat resistance to other inorganic polymers, so that when used, it is preferably used in combination with other inorganic polymers. Further, as the inorganic filler, magnesium oxide, aluminum oxide, zirconium oxide,
Titanium oxide, barium titanate, mica, silica and the like can be mentioned. Among them, magnesium oxide,
The use of mica is preferred. Furthermore, as the organic solvent,
Xylene, toluene, benzene, ethanol, N-methyl
-2-Pyrrolidone (NMP), phenols and the like can be mentioned. Silicone oil can also be used as a reaction solvent for polyborosiloxane.

The coating / baking layer 2 of the inorganic polymer coating is formed by coating and baking such an inorganic polymer coating by a conventional method. The baking temperature is 300 to 400 from the viewpoint of flexibility. The temperature is preferably in the range of 0 ° C., and the layer thickness is preferably about 5 to 50 μm.

Further, as the organic polymer heat-resistant paint constituting the coating and baking layer 3 of the organic polymer heat-resistant paint, those based on an aromatic imide polymer having excellent heat resistance such as polyamide-imide and polyimide are preferable. As the inorganic filler used and compounded therein, the same ones as those compounded in the above-mentioned inorganic polymer-based paint can be used. The coating / baking layer 3 of the organic polymer heat-resistant paint is composed of several kinds of organic polymer heat-resistant paints having different contents of the inorganic filler, for example, 90 to 100 parts by weight of the inorganic filler to 100 parts by weight of the base organic polymer heat-resistant paint. It can be formed by coating and baking a mixture of approximately 10 to 0 parts by weight of an inorganic filler in order of increasing concentration, and then baking it in order of a layer thickness of 5 to 50.
About μm is appropriate.

The coating / baking layer 3 of the organic polymer heat-resistant paint in which the inorganic filler is blended with a concentration gradient as described above imparts excellent flexibility to the electric wire, and at the same time, fires after processing such as coil winding. It is prevented that cracks or peeling occur in the coating / baking layer 2 of the inorganic polymer coating material during the process, and the original heat resistance thereof is impaired. Therefore, the heat-resistant insulated wire has good flexibility, and also has excellent heat resistance and insulating properties even after being processed by coil winding or the like.

In the present invention, the conductor 1 is
In addition to the Ni wire mentioned above, it has excellent heat resistance, such as Ag wire,
Au wires, Pt wires, Ni wires, Cu wires, alloy wires of these, Cu wires plated with these, or Cu wires coated with stainless steel or Al are used.

[0018]

As described above, in the heat resistant insulated wire of the present invention. , Inorganic polymer paint coating baking layer, inorganic filler is blended with a concentration gradient that is high on the coating baking layer side of the inorganic polymer coating and gradually decreases toward the surface side. A coating / baking layer of paint is provided.This coating / baking layer of organic polymer heat-resistant paint imparts excellent flexibility to electric wires, and also applies an inorganic polymer paint in the firing process after processing such as coil winding. In order to prevent the baking layer 2 from cracking or peeling, it has good flexibility and excellent heat resistance that can be used in a temperature environment of 400 ° C. or higher. Therefore, it is possible to carry out processing such as coil winding, and there is no fear that the processing will lower the heat resistance and impair the insulation characteristics.

[0019]

EXAMPLES Examples of the present invention will be described below.

Examples 1 to 3 Polyborosiloxane (50 parts by weight), silicone resin (50 parts by weight) and magnesium oxide (20 parts by weight) were mixed and dispersed in 40 parts by weight of NMP with a stirrer such as a mixer. Inorganic polymer paint is applied to 1 mmφ Ni wire using a baking machine with a furnace length of 10 m at a linear speed of 5 m / min and a baking temperature of 400 ° C.
The coating and baking was repeated 6 times to form a coating film of an inorganic polymer coating having a film thickness of 10 μm. Then, 100, 80, 60, 40, 20 parts by weight of magnesium oxide were added to 100 parts by weight of the polyimide varnish (containing about 18% by weight of polyimide) and mixed using a baking machine with a furnace length of 10 m. The five types of paints with different magnesium oxide contents prepared in this way were applied and baked once in order from the one with the highest magnesium oxide content under the conditions of a linear velocity of 5 m / min and a baking temperature of 300 ° C. A polyimide varnish containing no magnesium oxide was applied and baked once under the same conditions to obtain a film thickness.
A 30 μm polyimide coating was formed.

In order to evaluate the heat resistance of each of the obtained heat resistant insulated wires, a double twist test piece was prepared according to JIS C 3003,
These test pieces were housed in a hot air circulation oven at 300 ° C and 0, 3
It was heated for 60, 1000, 2000 hours and the dielectric breakdown voltage was measured.
In addition, the flexibility was evaluated by a winding test specified by JIS C 3003. The results are shown in Table 1.

Comparative Examples 1 to 4 Under the same conditions and the same method as in Example 1, except that a single kind of polyimide coating was used to form a polyimide coating film having a thickness of 30 μm. Heat-resistant insulated wires were produced, and the obtained heat-resistant insulated wires were evaluated for characteristics similar to those in Example 1 (Comparative Examples 1 to 3). In addition, as for the used polyimide paint, Comparative Example 1 is polyimide varnish.
One containing 100 parts by weight of magnesium oxide per 100 parts by weight, Comparative Example 2 containing 60 parts by weight of magnesium oxide per 100 parts by weight of polyimide varnish, Comparative Example 3
However, it does not contain magnesium oxide at all. Further, only a coating film made of an inorganic polymer coating was formed on a 1 mmφ Ni wire, and the obtained electric wire was evaluated for the same characteristics as in Example 1 (Comparative Example 4). The results are also shown in Table 1.

[0023]

[Table 1]

[0024]

As described above, according to the present invention,
An inorganic filler is applied on the coating and baking layer of the inorganic polymer paint.
The coating and baking layer of the organic polymer heat-resistant coating compounded with a concentration gradient that is high on the coating and baking layer side of the inorganic polymer type coating and gradually decreases toward the surface layer side is provided under a temperature environment of 400 ° C or higher. It has both excellent heat resistance and flexibility that can be used in, therefore, it is possible to process coil winding etc., and obtain a heat resistant insulated wire that does not impair its original excellent heat resistance after processing. be able to.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an embodiment of the heat resistant insulated wire of the present invention.

[Explanation of symbols]

1 ... Conductor 2 ... Inorganic polymer coating coating baking layer 3 ... Organic polymer heat resistant coating coating baking layer containing inorganic filler with concentration gradient

Claims (4)

[Claims] 1. A heat-resistant insulated wire comprising a conductor and a coating / baking layer of an inorganic polymer-based paint and a coating / baking layer of an organic polymer-based heat-resistant paint, which are sequentially provided on a conductor. The heat resistant insulated electric wire is characterized in that an inorganic filler is blended in the layer with a concentration gradient such that it is high on the coating / baking layer side of the inorganic polymer-based paint and gradually decreases toward the surface layer side. 2. The heat resistant insulated electric wire according to claim 1,
A heat-resistant insulated wire characterized in that an inorganic filler is not mixed in the surface layer of the coating / baking layer of the organic polymer heat-resistant paint. 3. The heat resistant insulated wire according to claim 1 or 2, wherein the inorganic polymer-based paint contains polyborosiloxane as a main component of a binder. 4. The heat-resistant insulated electric wire according to claim 1, wherein the organic polymer heat-resistant paint is a polyimide heat-resistant paint.