JPS6161203B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to an insulated wire having excellent heat resistance, mechanical properties, and chemical resistance, and particularly excellent thermal shock resistance after impregnation treatment. BACKGROUND ART Conventionally, heat-resistant synthetic resins include polyester resins such as polyester resins and polyesterimide resins, polyamide-imide resins such as polyamide-imide resins, and polyesteramide-imide resins, and polyimide resins. As a method for obtaining a polyester resin, a method is generally known in which dicarboxylic acid or a derivative thereof (such as methyl ester), imidodicarboxylic acid, or a mixed acid component thereof is reacted with a polyol. It is possible to use an inexpensive phenolic solvent such as xylenol at a high concentration, and there are also known methods such as making it water-soluble and melting it, and applying these polyester resin solutions to the conductor. Although baked polyester insulated wires have excellent heat resistance, they do not have sufficient thermal shock resistance, mechanical properties, chemical resistance, etc., and there are concerns about the reliability of equipment. In addition, as a method for obtaining polyamide-imide resin, there is a method in which tricarboxylic acid anhydride and diisocyanate are reacted in an organic polar solvent, and a method in which excess tricarboxylic acid anhydride and diisocyanate are reacted in a phenolic solvent and then a polyol is further added. Polyamide-imide insulated wires made by coating and baking these polyamide-imide resin solutions on conductors have excellent heat resistance, thermal shock resistance, mechanical properties, and chemical resistance, and have well-balanced properties. have. Furthermore, as a method for obtaining polyimide resin,
There is a known method in which an aromatic tetracarboxylic dianhydride and a diamine are reacted in an organic polar solvent to form a soluble polyamic acid resin solution, and this polyamic acid resin solution is converted into a polyimide resin by heat treatment before use. However, polyamic acid resin solutions are extremely unstable and imidization occurs gradually even at room temperature, causing the solution to gel, requiring frozen storage.
In addition, only expensive and highly hygroscopic solvents such as N-methyl-2-pyrrolidone, dimethylacetamide, and dimethylformamide can be used as solvents, and the resulting paint is expensive and has low resin concentration, making it difficult to form wires. Therefore, polyimide insulated wires using this paint had the disadvantage of being expensive. On the other hand, polyimide resin obtained by reacting 1,2,3,4-butanetetracarboxylic acid and diamine in a phenolic solvent can be used in high concentration, and 1,2,3,4-butane A polyamic acid resin obtained by reacting a tetracarboxylic dianhydride and a diamine in an organic polar solvent can be easily made water-soluble, compared to the case where the aromatic tetracarboxylic dianhydride is used. Although it has poor heat resistance, it is useful as a low-pollution resin solution by increasing its concentration or making it water-soluble, and the resin solution is thermally stable and has excellent wire-making processability. However, when the present inventors investigated the varnish resistance of heat-resistant insulated wires manufactured using these heat-resistant resin coatings, they found that polyamide-imide-based insulated wires and polyimide with 1,2,3,4-butanetetracarboxylic acid units After coil processing, insulated wires are impregnated with impregnating resins commonly used for coil impregnation, such as polyester resin, epoxy resin, phenol resin, or a mixture of these resins, resulting in better thermal shock resistance than polyester insulated wires. It was found that the characteristics were significantly degraded. The present invention relates to a polyamide-imide insulated wire and a
This relates to an improvement of polyimide-based insulated wires consisting of 2,3,4-butanetetracarboxylic acid units, and relates to highly reliable insulated wires that have improved the above-mentioned drawbacks. 1・
First insulating layer made of polyimide resin or polyamideimide resin containing 2,3,4-butanetetracarboxylic acid units 2 Second insulating layer made of polyester resin 31,2,3,4-butanetetracarboxylic acid units A third insulating layer 4 made of a polyimide resin or a polyamide-imide resin is sequentially provided (except when the first insulating layer and the third insulating layer are made of a polyamide-imide resin). The third insulating layer 4 is characterized in that the thickness thereof is within a range of 5 to 30% of the total insulating layer thickness. To explain the present invention in more detail, the causes of the above-mentioned defects in polyamide-imide insulated wires and polyimide insulated wires containing 1,2,3,4-butanetetracarboxylic acid units are not clear, but the phenomenon The impregnated resin layer that is in direct contact with the air deteriorates due to heat and cracks occur, and these cracks spread to the polyamide-imide resin layer or polyimide resin layer that is in close contact with the impregnated resin layer, and eventually reach the conductor. Ta. On the other hand, in the polyester insulated wire, even if a crack occurred in the impregnated resin layer, this crack did not spread to the polyester resin layer that was in close contact with the impregnated resin layer. Upon discovering this fact, the inventors interposed a polyester resin in the middle of an insulating layer made of a heat-resistant resin such as polyimide resin or polyamide-imide resin. Even if the cracks deteriorate and spread to the outermost polyimide resin or polyamide-imide resin layer, the cracks that occur will be alleviated by the intermediate polyester resin layer and will not spread to the lower polyimide resin layer. The inventors have discovered that a highly reliable insulated wire can be obtained, which does not suffer from the drastic deterioration in thermal shock resistance after treatment with an impregnated resin, as seen in conventional products. In the present invention, the reason why the insulating layer has the above-mentioned composite structure is that the third insulating layer of polyamide-imide resin or the polyimide-based resin layer of 1,2,3,4-butanetetracarboxylic acid units is the second insulating layer. In addition to mechanical properties, which are a drawback of the polyester resin layer, it is coated for the purpose of improving chemical resistance, and the thickness is preferably 5 to 30% of the total insulating layer thickness. The reason for this is that when the thickness of these insulating layers is less than 5%, mechanical properties, chemical resistance, etc. deteriorate.
The reason for limiting the thickness to 30% or less is that if these insulating layers have a thickness of 30% or more of the total insulating layer thickness, cracks may occur in the impregnated resin layer due to thermal shock after the impregnated varnish treatment, as described above. This is because even if the cracks do not spread to the underlying polyimide resin or polyamide-imide resin layer and reach the conductor, the thermal shock resistance deteriorates, probably because the cracks become deeper. In addition, the polyester resin layer of the second insulating layer prevents the thermal shock resistance from decreasing as seen in polyamide-imide insulated wires and polyimide insulated wires containing 1,2,3,4-butanetetracarboxylic acid units due to impregnation varnish treatment. Although it is provided for the purpose of preventing polyamide-imide insulated wires and
In order to maintain the excellent properties of the polyimide insulated wire containing 3,4-butanetetracarboxylic acid units,
It is recommended that the thickness be 30% or less of the total insulation layer thickness. However, if it is too thin, it will not serve to prevent the thermal shock resistance from deteriorating after the impregnation varnish treatment, so the thickness must be at least 5% or more. As described above, the insulated wire of the present invention has excellent mechanical properties, chemical resistance, and thermal shock resistance after being treated with impregnated varnish, and can be suitably used to improve the reliability of equipment. Further, in the insulated wire of the present invention, it is preferable that the third insulating layer is formed of a polyamide-imide resin because it has particularly excellent wear resistance and improves automatic winding processability. In addition, as the polyamide-imide resin referred to in the present invention, for example, one made by the following method is used. Example 1 1.0 mol of trimellitic anhydride and 1.05 mol of diphenylmethane diisocyanate were mixed with N-methyl-
A resin obtained by heating and drying a polyamideimide resin solution obtained by a heating reaction in 2-pyrrolidone. Example 2 Trimellitic anhydride 4-aryl ester
0.5 mol and 0.4 mol of diaminodiphenylmethane were reacted by heating without a solvent or in a solvent, and then 0.3 mol of tris(2-hydroxyethyl)isocyanurate, 0.1 mol of ethylene glycol, and 0.3 mol of dimethyl terephthalate were added and the mixture was reacted with heating. A resin obtained by heating and drying a phenolic solvent-soluble polyesteramideimide resin solution. In addition, the polyester resin referred to in the present invention is, for example, Isonel 200 manufactured by Nippon Schenectaday Co., Ltd.
Resins obtained by heating and drying polyester resin solutions such as Nitto Denko's product name Decorate E210G, Dainichiseika Chemical Co.'s product name Arobetsu E-541, and Nissoku Schenectaday's product name Isomit RH, etc. used. Furthermore, the tetracarboxylic acid unit is 1, 2, 3, 4
- The polyimide resin consisting of butanetetracarboxylic acid units is, for example, Nitto Denko's product name X-400.
Alternatively, a resin obtained by heating and drying X-600W or the like may be used. The present invention will be illustrated below with examples. Example 1 Polyimide resin paint (product name: A 0.007 mm polyesterimide resin layer was formed by applying and baking Isomitzu (trade name: Isomit RH manufactured by Nippon Schenectaday), and then a 0.008 mm polyimide resin layer was applied and baked on top of this by applying polyimide resin paint (trade name: X-600W). An insulated wire with a finished outer diameter of 1.092 mm was obtained. Examples 2 to 5 Table 1 shows the structures of insulated wires obtained in the same manner as in Example 1, using each of the resin coatings used in Example 1 and varying the thickness of each resin layer.

[Table] Example 6 The polyester amide-imide resin solution obtained in Example 2 was coated and baked on a copper wire with a core diameter of 1.000 mm to form a 0.030 mm resin layer, and a polyester resin paint (commercial product) was applied on top of this. name isonel
Apply and bake 200 days (manufactured by Schenectaday)
A 0.008 mm polyester resin layer is provided, and then a polyimide resin paint (product name: I got it. Example 7 Polyimide resin paint (product name:
E210G manufactured by Nitto Denko Corporation) was applied and baked to form a 0.008 mm polyester resin layer, and on top of this, the polyamide-imide resin solution obtained in Example 1 was applied and baked to form a 0.008 mm resin layer, resulting in a finished outer diameter.
A 1.092mm insulated wire was obtained. Reference Example 1 The polyamide-imide resin solution obtained in Example 1 above was applied and baked on a copper wire with a core wire diameter of 1.000 mm by a conventional method to form a resin layer of 0.046 mm, resulting in a finished outer diameter of 1.092 mm.
A polyamide-imide insulated wire of mm was obtained. Reference Example 2 An insulated wire with a finished outer diameter of 1.093 mm was obtained in the same manner as in Reference Example 1 using a polyimide resin paint (trade name: X-600W) on a copper wire with a core wire diameter of 1.000 mm. Reference Example 3 An insulated wire with a finished outer diameter of 1.092 mm was obtained in the same manner as in Reference Example 1 using a polyester resin paint (trade name: Isomid RH) on a copper wire with a core wire diameter of 1.000 mm. Reference example 4 Polyimide resin paint (product name:
RH) was applied and baked to form a 0.020mm polyesterimide resin layer, and on top of this, a polyimide resin paint (product name X-600W) was applied and baked to form a 0.003mm layer.
Finished with a polyimide resin layer with an outer diameter of 1.092 mm.
An insulated wire was obtained. Reference Examples 5 to 6 Table 2 shows the structures of insulated wires obtained in the same manner as in Reference Example 4 using each of the resin coatings used in Example 1 and varying the thickness of each resin layer.

[Table] In Examples 1 to 7 and Reference Examples 1 to 6, a vertical furnace was used for baking the paint, and the baking temperature was 400°C and the linear speed was 9.
The test was carried out under conditions of m/min. The thermal shock resistance properties of the insulated wires obtained in Examples 1 to 7 and Reference Examples 1 to 6 were evaluated by preparing two twisted samples according to the dielectric breakdown section of JIS-C-3003, and applying each sample to an impregnating resin solution. Soaked in water for 1 minute and air-dried for 30 minutes.
After heating and curing at ℃ for 30 minutes and 150℃ for 3 hours,
After repeating the heating-cooling test below, apply 1.000V between the lines at room temperature and calculate the number of cycles when the lines are short-circuited.

[Table] 〓 〓
In addition, as for mechanical properties, each insulated wire is JIS
Tested according to the reciprocating wear resistance section specified in -C-3003. Furthermore, for chemical resistance, a helical coil in which each insulated wire was tightly wound about 10 turns around a 20 mm round rod was immersed in xylene for 2 minutes to check for crazing. The helical coil was immersed in Freon (R-22) at 90°C for 3 days and then immediately heated at 150°C for 10 minutes, and the presence or absence of film foaming was examined. The above test results are shown in Table 3.

【table】

[Table] As is clear from the results in Table 3, the insulated wire of the present invention has excellent thermal shock resistance after impregnation treatment, as well as excellent mechanical properties and chemical resistance, and improves the reliability of electrical equipment. It can be suitably used for.

[Brief explanation of the drawing]

The figure is an example of a cross-sectional view of an insulated wire obtained by the present invention. 1 is an electric conductor, 2 is a polyimide resin film layer,
3 is a polyester resin film layer, and 4 is a polyimide resin film layer.

Claims (1)

[Claims] 1. On the conductor, the tetracarboxylic acid units are 1, 2,
A first insulating layer made of polyimide resin or polyamideimide resin which is 3,4-butanetetracarboxylic acid unit, a second insulating layer made of polyester resin, and tetracarboxylic acid unit is 1,2,
A third insulating layer made of a polyimide-based resin or a polyamide-imide-based resin, which is a 3,4-butanetetracarboxylic acid unit, is sequentially provided (However, when the first insulating layer and the third insulating layer are made of a polyamide-imide resin, An insulated wire characterized in that the thicknesses of the second insulating layer and the third insulating layer are each within a range of 5 to 30% of the total insulating layer thickness. 2. The insulated wire according to claim 1, wherein the third insulating layer is made of polyamide-imide resin.