JPS6233725B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to an insulated coil. Conventionally, insulated wire rings have been produced by winding peelable mica tape or the like around a conductor, impregnating it with a thermosetting resin composition such as an epoxy resin composition or an unsaturated polyester resin composition in a vacuum, and then curing it, or by baking it and assembling it. It is manufactured by a so-called prepreg method in which a mica prepreg tape or the like is wound around a conductor and then heated and press-molded. The prepreg method was superior in initial electrical properties, but the vacuum impregnation method using peelable mica tape was superior in initial mechanical properties and electrical properties after long-term electrical deterioration. There are no insulated wire rings made of laminated mica that have properties equal to or better than those made of peelable mica, and those with electrical properties comparable to those using peelable mica are described in Japanese Patent Publication No. 50-20264. It is shown. This method has disadvantages, such as the complicated manufacturing process of infiltrating the raw material mica block with an aqueous solution of hydrofluoric acid or hydrogen chloride, and the need for wastewater treatment, and the mechanical properties of the resulting insulated wire are insufficient. However, I could not say that. The present invention solves these drawbacks and provides an insulated wire ring with excellent electrical and mechanical properties. The present invention uses 30 to 70 parts by weight of mica flakes, which are obtained by crushing unfired mica and have a particle size of 1.0 mm or more and an aspect ratio of 150 or more, and a particle size of 0.25 mm or more to 1.0
20 to 40 parts by weight of mica flakes less than mm, particle size 0.25
60 to 85 parts by weight of a laminated mica material obtained by paper-making a slurry containing 10 to 30 parts by weight of mica scale pieces of less than mm in size, 15 to 30 parts by weight of a thermosetting resin composition, and 15 parts by weight or less of a backing material. The present invention relates to an insulated coil having an insulating layer containing the same. The method for forming the insulating layer may be either a prepreg method or a vacuum impregnation method, and the conditions for forming it are not limited. When calcined mica is used instead of uncalcined mica, the mechanical properties of the insulated wire, especially the bending strength and bending elastic modulus, are significantly reduced. What is the aspect ratio in the present invention? Aspect ratio = diameter of mica scale piece / thickness of mica scale piece, and particle size distribution was calculated by measuring the weight after drying after wet classification using a standard analysis sieve. Although there was no method for pulverizing unfired mica to the particle size distribution and aspect ratio of the present invention,
This was made possible for the first time by methods disclosed in Japanese Patent Application Laid-open No. 8899 and Japanese Patent Application Laid-Open No. 53-39984. By these methods, mica flakes having a large aspect ratio and a desired particle size distribution can be easily obtained. If the mica scale particles with a particle size of 1.0 mm or more and an aspect ratio of 150 or more are less than 30 parts by weight, the reinforcing effect of the mica scale particles is small, resulting in a decrease in the mechanical properties of the insulated wire, and if it exceeds 70 parts by weight, The mechanical properties of the insulated coil are good, but the electrical properties are degraded. Also particle size
If the aspect ratio of mica flakes of 1.0 mm or more is less than 150, both the mechanical and electrical properties of the insulated wire will deteriorate. If less than 10 parts by weight of mica scale pieces with a particle size of less than 0.25 mm are included, the voids of mica scale pieces with a particle size of 1.0 mm or more cannot be sufficiently filled, and therefore the thermosetting resin composition in the insulating layer This requires more than 30 parts by weight of the insulated wire, which deteriorates the mechanical properties of the insulated wire and further deteriorates the electrical properties after long-term deterioration. Further, if it is contained in an amount exceeding 30 parts by weight, the reinforcing effect of the mica scale pieces is small, and the mechanical properties of the insulated wire ring are deteriorated, which is not preferable. The above particle size is less than 0.25mm mica flakes and 1.0mm
When only the above mica scale pieces are combined, the settling speed of the former and the latter differs by more than 10 times, so when making paper with a wet paper machine, large mica scale pieces are on one side, and small mica scale pieces are on the other side. It becomes mica flakes and is difficult to pack closely. To solve this problem, particle size should be 0.25mm or more, 1.0mm
Less than 20 to 40 parts by weight of mica flakes are used together.
If it is less than 20 parts by weight, the effect of adding it will be small, and if it exceeds 40 parts by weight, the mechanical properties of the resulting insulated wire wheel will deteriorate. There are no particular restrictions on the method of forming mica scale pieces into a laminated mica material, and the method is usually to make a slurry containing 0.5 to 2% by weight of mica scale pieces, and then use a fourdrinier type, circular wire type, etc. paper machine. Obtained by papermaking. The method for forming the insulating layer can be either the vacuum impregnation method or the prepreg method.
Furthermore, there are no restrictions on the conditions for formation. If necessary, a laminated mica material with a backing material is wound around a conductor, and this is placed in a reduced pressure atmosphere and impregnated with a thermosetting resin composition or pressure impregnated, and then the thermosetting resin composition is cured to form an insulated wire ring. Alternatively, the assembled mica material is impregnated with a thermosetting resin composition and semi-cured to obtain an assembled mica prepreg material, which is then wound around a conductor and the impregnated thermosetting resin composition is cured. It is considered an insulated wire ring. The thermosetting resin composition in the present invention includes:
Epoxy resin compositions, unsaturated polyester resin compositions, etc. containing hardening agents, surfactants, solvents, reactive solvents, etc. are used, and there are no particular limitations. The backing material in the present invention is not particularly limited, and for example, organic or inorganic woven fabrics, nonwoven fabrics, films, etc. such as polyester, polyamide, glass, etc. may be used alone or in combination if necessary, and furthermore, these may be used in combination with glass yarn, polyester fibers, etc. It is okay to use a combination of yarns, etc. The aggregate mica material is used in an amount of 60 to 85 parts by weight, the thermosetting resin composition is used in an amount of 15 to 30 parts by weight, and the backing material is used in an amount of 15 parts by weight or less, so that the total amount thereof is 100 parts by weight. The laminated mica material is used in a range of 60 to 85 parts by weight, but if it is less than 60 parts by weight, the electrical properties such as withstand voltage of the insulated wire will deteriorate, and if it exceeds 85 parts by weight, there will be many voids between mica flakes. As a result, the electrical and mechanical properties of the insulated wire are significantly reduced. If the thermosetting resin composition in the insulating layer is less than 15 parts by weight, voids are likely to be formed in the insulating layer, and these voids may cause corona discharge, reduce the electrical properties of the insulated wire, and cause bending, compression, etc. If the thermosetting resin composition in the insulating layer is less than 15 parts by weight, voids are likely to occur in the insulating layer, and these voids may cause corona discharge, reduce the electrical properties of the insulated wire, and cause bending and compression. When such stress is applied to the insulating layer, stress concentration occurs and the mechanical properties also deteriorate. If the thermosetting resin composition in the insulating layer exceeds 30 parts by weight, not only the mechanical properties will deteriorate, but also the electrical properties after long-term deterioration. The backing material is used by laminating it with the laminated mica material as necessary, and does not necessarily have to be used.
If it exceeds 15 parts by weight in the insulating layer, the mechanical or electrical properties of the insulated wire will deteriorate. For example, if more than 15 parts by weight of glass fiber woven or non-woven fabric is used as a backing material, the mechanical properties will not deteriorate, but the electrical properties will deteriorate; If more than 15 parts by weight is used, the mechanical properties will deteriorate, and the electrical properties will also deteriorate after long-term deterioration. Similar results are obtained when the above-mentioned film is combined with fiber yarns such as glass and polyester. The present invention will be explained below with reference to Examples. Example 1 Sheet (laminated mica material) 1 described in Table 1 and Table 2
The described epoxy resin composition was heated to 60°C.
Coated with 100g/ ^m2 and glass cloth (35g/m2)
m ² ) was laminated as a backing material and semi-cured by heating at 80° C. for 1 hour to obtain a laminated mica prepreg material.
After cutting this into 30mm wide prepreg tape, wrap it 8 times around a 9.5mm wide x 36.5mm tall x 1000mm long conductor (made of copper), overlapping half of it, then heat it to 100℃ and press it to create a mica prepreg tape. While flowing the above epoxy resin composition in the material
Raise the temperature to 170℃ and cure (3 hours) to a thickness of approximately 3mm.
A coil with an insulating layer was fabricated. There are 4 coils
Two pieces of this product were tested under normal conditions, and two pieces were tested after a heat deterioration test ( ¹⁰³ hours at 130°C). The test measured the dielectric breakdown voltage at a boost rate of 2KV/sec, followed by a 4-point bending test (outer span 550mm, inner span 250mm, test speed 5
mm/min). The amount of adhesive (epoxy resin composition)
It was determined by heating at 600°C for 2 hours. The results are shown in Table 3 as average values. Example 2 A prepreg tape was prepared using Sheet 2 listed in Table 1 and the epoxy resin composition listed in Table 2 under the same conditions as Example 1. After wrapping this 8 times around the conductor used in Example 1, overlapping half of it, Example 1
Four coils were manufactured under the same conditions. Tests were conducted under the same conditions as in Example 1, and the results are shown in Table 3 as average values. Comparative Example 1 A prepreg tape was prepared using Sheet 3 listed in Table 1 and the epoxy resin composition listed in Table 2 under the same conditions as in Example 1. After wrapping this 8 times around the conductor used in Example 1, overlapping half of it, Example 1
Four coils were manufactured under the same conditions. Tests were conducted under the same conditions as in Example 1, and the results are shown in Table 3 as average values. Comparative Example 2 A prepreg tape was prepared using Sheet 4 listed in Table 1 and the epoxy resin composition listed in Table 2 under the same conditions as in Example 1. This was wound around the conductor used in Example 1 eight times with half overlap, and then four coils were manufactured under the same conditions as Example 1. Tests were conducted under the same conditions as in Example 1, and the results are shown in Table 3 as average values. Comparative Example 3 A prepreg tape was prepared using Sheet 5 listed in Table 1 and the epoxy resin composition listed in Table 2 under the same conditions as in Example 1. This was wound around the conductor used in Example 1 eight times with half overlap, and then four coils were manufactured under the same conditions as Example 1. Tests were conducted under the same conditions as in Example 1, and the results are shown in Table 3 as average values. Example 3 Crow cloth (35g/
m ² ) as a reinforcing material, and on top of this, 75 g/m ² of varnish made by dissolving the epoxy resin composition listed in Table 2 in methyl ethyl ketone to make the non-volatile content 20% by weight.
(15 g/m ² in terms of non-volatile content) was coated, dried at 100°C for 30 minutes, cut into 30 mm wide tapes to make prepreg tape, and then wrapped 8 times around the conductor used in Example 1, overlapping half of the tape. After that, 0.1 at 100℃
mmHg, 2 hours drying and then under that pressure 80
It was impregnated with the epoxy resin composition listed in Table 2 heated to .degree. With the coil immersed in the epoxy resin composition, the pressure was returned to normal pressure, and after 1 hour, the coil was taken out and wrapped in 2 mil mylar film (manufactured by Toray Industries, Inc.) to prevent the epoxy resin from dripping.
Cure for 4 hours at 170℃, then cure for 3 hours at 170℃.
An insulating layer with a thickness of mm was formed. Tests were conducted under the same conditions as in Example 1, and the results are shown in Table 3 as average values. Comparative Example 4 Sheet 5 shown in Table 1 was made into a prepreg tape under the same conditions as in Example 3, and then into a coil under the same conditions as in Example 3. Tests were conducted under the same conditions as in Example 1, and the results are shown in Table 3 as average values.

【table】

【table】

[Table] In Table 3, the amount of the epoxy resin composition was determined from the amount of weight loss after heating the insulating layer at 600° C. for 2 hours. Bending strength is 550mm outer span using 4-point method.
The inner span was 250 mm and the test speed was 5 m/min. The dielectric breakdown voltage was determined at a voltage increase rate of 2 KV/sec. The dielectric breakdown voltage after deterioration was determined by performing thermal deterioration at 130°C for 10 ³ hours in a hot air circulating electric dryer. The insulating wire ring according to the present invention uses a composite mica material with large mica flakes and a high aspect ratio, so the mechanical properties of the insulating layer are improved,
Furthermore, the gaps between larger mica flakes can be filled with smaller mica flakes, and the electrical properties of the insulating layer can also be improved. In addition, by using a laminated mica material in which the gaps between large mica flakes are filled with small mica flakes, the initial properties (electrical properties and mechanical properties) of the insulated wire ring can be maintained even if the amount of adhesive in the insulating layer is reduced. Not only does it not deteriorate, but it also has excellent characteristics after long-term deterioration (for example, long-term electrification deterioration characteristics), and can rival or even exceed insulated wire rings using peelable mica products.

Claims (1)

[Claims] 1 Particle size 1.0mm obtained by crushing unfired mica
30 to 70 parts by weight of mica flakes with an aspect ratio of 150 or more, 20 to 40 parts by weight of mica flakes with a particle size of 0.25 mm or more and less than 1.0 mm, and 10 parts by weight of mica flakes with a particle size of less than 0.25 mm. 60 to 85 parts by weight of a laminated mica material obtained by paper-making a slurry containing ~30 parts by weight;
15 to 30 parts by weight of the thermosetting resin composition and 15 parts by weight or less of the backing material (the total amount of the laminated mica material, thermosetting resin composition, and backing material is within the above range)
100 parts by weight)