JPH11213757A - Mica tape - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a mica tape with improve impregnating property with a resin material for impregnation and a prolonged service life. SOLUTION: This mica tap 1 is constituted of a treated substrate 2, a promoting agent protective layer 4 formed by immersing the treated substrate 2 in the solution of a polyethylene-vinyl acetate copolymer and drying the substrate, a mica sheet lever 7, and an adhesive layer 5 formed from an epoxy resin material. The solution of polyethylene-vinyl acetate has a melting point higher than the temperature at the time of impregnation treatment with a liquid epoxy type synthetic resin material to impregnate the electric insulation layer, which is formed by using the mica tape 1, with and lower a the hardening temperature at the time of thermal hardening and is compatible with the epoxy-based synthetic resin material and slightly reactive with a metal slats (the curing promoting agent) as a sole material. The treated substrate 2 is constituted of a substrate 8 of a tape-like fabric or unwoven fabric made of glass material fibers or polymer material fibers and the curing promoting agent 3 formed by immersing the substrate 8 in a solution of a metal salt and drying the resultant substrate 8.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mica tape used for an electrical insulating layer such as a coil for a high-voltage rotating electric machine, and is an improved mica tape for improving the impregnation property of a resin material for impregnation and extending the pot life. Related to the configuration.

[0002]

2. Description of the Related Art As is well known, an electric insulating layer used for a coil for a high-voltage rotating electric machine and required to have high electric insulation performance is formed by winding a mica tape plural times.
This is generally formed by impregnating a liquid impregnating resin material (for example, an epoxy resin material). This mica tape used for the electrical insulating layer is a tape-like woven fabric or nonwoven fabric (for example, polyester fleece) made of glass or polymer fibers, and an adhesive (for example, for impregnation). Resin material of the same type as resin material)
It is formed by bonding a mica sheet using

[0003] The polymer material applied to the base material of the mica tape is, for example, a polyester resin, an aramid resin, a polyamide imide resin, a polyimide ether resin, a polyether ketone resin, a polyether sulfone resin or a polyphenylene sulfide resin. Further, a well-known aramid-mixed paper may be used as the base material. The mica sheet used for the mica tape is generally peeled mica or laminated mica.

A conventional mica tape will be further described with reference to FIG. FIG. 4 is a cross-sectional view schematically showing a conventional mica tape. In FIG. 4, reference numeral 9 denotes a substrate 8 having the above-described contents, a mica sheet layer 7 formed using the above-described mica sheet, and a mica sheet
Is a mica tape comprising an adhesive layer 6 to be adhered to the mica tape. The base material 8 is formed by knitting a base material 8 in a vertical direction and a base material 8 in a horizontal direction. For example, the base material 8 shown in a cross section is a base material in a vertical direction, a base material 8 extending in a meandering shape. Can be understood as a lateral substrate. An example of a case where a ground insulating layer (also referred to as a main insulating layer) of a well-known stator coil for a high-voltage rotating electric machine is formed as an electric insulating layer required to have high electric insulating performance is an electric insulating layer. A ground insulating layer (not shown) is formed by first forming a wound layer formed by winding the mica tape 9 a plurality of times, and then impregnating the wound layer with a liquid impregnating resin material by a vacuum pressure impregnation method. .

The method of impregnating the liquid impregnating resin material includes a treatment method for each stator coil having a wound layer (simple impregnation method) and an individual stator coil having a wound layer. 2. Description of the Related Art There is known a processing method (a total impregnation processing method) in which a coil is mounted on a known stator core, and a plurality of stator coils provided in the stator core are simultaneously connected after electrical connection or the like is completed. In the simple impregnation method, the impregnation of the liquid impregnating resin material uses a mold with a tightening structure,
It is common to perform this process with the ground insulating layer tightened.

Regardless of whether a single impregnation method or a full impregnation method is employed, as a liquid impregnation resin material, at present, an epoxy resin (monomer) (for example,
A liquid epoxy resin material in which bisphenol A type or bisphenol F type epoxy resin) and an acid anhydride (curing agent) are mixed at an appropriate compounding ratio is often used. Then, the wound layer in which the liquid epoxy resin material is vacuum impregnated is subjected to a heat curing treatment to cure the epoxy resin material, thereby forming a ground insulating layer. When a liquid epoxy resin material is used as the impregnating resin material, a curing accelerator is generally used in combination to accelerate the curing reaction of the epoxy resin material.
Therefore, in the mica tape 9, the adhesive layer 6 is formed using a mixture of an epoxy resin as an adhesive and a curing accelerator.

The method of adding a curing accelerator to mica tape is performed by applying a curing accelerator around a mica tape formed by an adhesive (epoxy resin) layer containing no curing accelerator. There are also known ways to do this. Regardless of which method is used, the curing accelerator includes, for example, a curing reaction between an epoxy resin material such as tertiary amines, amines, quaternary ammonium salts, imidazoles, and metal salts and a curing agent. A material having a function of promoting the above is used. As tertiary amines, trimethylamine, triethylamine, tetramethylbutanediamine, triethylenediamine and the like are known. As amines, dimethylaminoethanol, tris (dimethylaminomethyl) phenol,
N-methylmorpholine and the like are known.

The quaternary ammonium salts include:
Cetyltrimethylammonium bromide, dodecyltrimethylammonium bromide, benzyldimethyltetradecylammonium bromide and the like are known. Examples of imidazoles include 2-methylimidazole, 2-ethylimidazole, 2-undecylimidazole, 2-methyl-4-ethylimidazole,
Benzyl-2-methylimidazole and the like are known. Further, as metal salts, metal salts of amine and zinc octoate and cobalt, and organic acid metal salts such as zinc naphthenate are known.

In order to impregnate the wound layer formed by using the mica tape 9 or the like, for example, by vacuum pressure impregnation of a liquid epoxy-based synthetic resin material by the simple impregnation method, the wound layer In order to sufficiently impregnate the synthetic resin material, an impregnation tank capable of accommodating a plurality of stator coils at the same time is prepared. Then, these stator coils are accommodated in this impregnation tank into which the synthetic resin material has been injected, and the stator coil in this state is vacuum-impregnated with the synthetic resin material. A procedure of pressurizing with dry air is performed. Therefore, it is necessary to prepare a much larger amount of synthetic resin material than the amount actually impregnated in the ground insulating layer. Therefore, a large amount of the synthetic resin material is prepared at a time, and the stator coil is impregnated repeatedly using the large amount of the synthetic resin material many times more than 100 times.

At this time, in order to sufficiently impregnate the wound layer with the synthetic resin material, it is necessary to lower the viscosity of the synthetic resin material. It is necessary to keep the temperature at a high value of several tens of degrees. However, the curing accelerator possessed by the mica tape 9 or the like has a well-known property that the curing of the synthetic resin material is rapidly accelerated when the temperature exceeds a certain temperature. If it exceeds, the synthetic resin material is cured before being sufficiently impregnated into the wound layer, so that impregnation failure occurs. For this reason, the impregnation temperature is determined in consideration of both the impregnation of the wound layer with the synthetic resin material and the reactivity of the curing accelerator.

[0011]

The formation of the electrical insulation layer by impregnating the wound layer of the mica tape using the above-mentioned prior art mica tape 9 with an epoxy-based synthetic resin material involves forming the electrical insulation layer. Can be formed stably, but there are the following problems, and improvement thereof is desired. That is, the curing accelerator of the mica tape 9 or the like gradually advances the curing reaction of the liquid epoxy-based synthetic resin material as the resin material for impregnation even at an appropriate impregnation temperature due to its properties. Therefore, in the case where the synthetic resin material is impregnated into the electric insulating layer having a large thickness, the viscosity of the synthetic resin material that has penetrated into the electric insulating layer gradually increases due to the progress of the curing reaction, and the deeper the synthetic resin material, the deeper the synthetic resin material. Penetration into the electrical insulation layer becomes difficult. When the curing reaction for the synthetic resin material progresses, the synthetic resin material is gelled, and no further permeation is performed, and impregnation failure occurs. In the electric insulating layer in which impregnation failure has occurred in the synthetic resin material, the well-known local discharge easily occurs, and the electric insulating performance and the long-term reliability of the electric insulating layer deteriorate.

As described above, the curing accelerator of the mica tape 9 or the like is added to the adhesive layer 6 as a mixture with the epoxy resin, or the mica tape 9 is formed of an epoxy resin containing no curing accelerator. It is applied around a mica tape formed by bonding a sheet to a base material, and is provided as a curing accelerator layer. Therefore, regardless of the mica tape having any structure, the epoxy resin used for bonding the mica sheets is in contact with the curing accelerator. For this reason, during storage of the mica tape, the epoxy-based resin reacts slowly with the curing accelerator, but cures, so that the mica tape of the prior art has a limited pot life. In order to extend the pot life, mica tapes need to be stored at a low temperature.

SUMMARY OF THE INVENTION The present invention has been made in consideration of the above-mentioned problems of the prior art, and has as its object to provide a mica tape that improves the impregnation property of a resin material for impregnation and extends the pot life. It is in.

[0014]

According to the present invention, there are provided the following objects: 1) A tape formed from a fiber material made of an electric insulating material and treated with a curing accelerator which promotes the reaction of the resin material for impregnation. Provided substrate, comprising an accelerator protective layer covering the substrate from the outside of the layer of the curing accelerator, and a mica sheet bonded to the substrate using an adhesive via the accelerator protective layer, The polymer material used for the accelerator protective layer has a melting point higher than the temperature at the time of the impregnation treatment of the impregnation resin material and lower than the curing temperature of the impregnation resin material, and is compatible with the impregnation resin material. Or a composition having a small reactivity alone with the curing accelerator, or 2) In the means described in the above item 1, the base material protects the curing accelerator with the accelerator. A layer of a curing accelerator which is a mixture with the polymer material used for the layer 3) In the means described in the above item 1 or 2, the adhesive for bonding the mica sheet to the base material is a polymer material used for the accelerator protective layer. Or 4) In the means described in the above item 1 or 2, the adhesive for adhering the mica sheet to the base material is the same as the adhesive used for the accelerator protective layer. This is achieved by adopting a configuration using a molecular material.

[0015]

Embodiments of the present invention will be described below in detail with reference to the drawings. In the following description of this section, the same portions as those of the conventional mica tape shown in FIG. 4 are denoted by the same reference numerals, and description thereof will be omitted. FIG.
1 is a drawing schematically showing a mica tape according to an example of an embodiment of the present invention, and FIG.
FIG. 2B is a sectional view taken along line AA in FIG. FIG.
In the above, reference numeral 1 denotes a substrate (hereinafter abbreviated as a treated substrate) 2 which has been treated with a curing accelerator, an accelerator protective layer 4, a mica sheet layer 7, and an adhesive layer 5. Mica tape. The treated substrate 2 is obtained by treating the above-described substrate 8 with the above-described curing accelerator. Therefore, the curing accelerator layer 3 which is a layer of the curing accelerator is formed around the fibers constituting the substrate 8. [See FIG. 1 (b)]. In addition, the processed base material 2 is formed by knitting the processed base material 2 in the vertical direction and the processed base material 2 in the horizontal direction. It can be understood that the processed substrate 2 extending in a meandering shape is a lateral substrate.

The promoter protective layer 4 is formed using a polymer material, and is a layer characteristically provided in the mica tape 1 according to the present invention. The polymer material used for the accelerating agent protective layer 4 has a melting point higher than the temperature at the time of the impregnation of the liquid impregnating resin material impregnated into the electric insulating layer, and heat-curing of the impregnating resin material. It must be lower than the curing temperature at the time. Further, the polymer material needs to have compatibility with the resin material for impregnation, and have a small reactivity with the curing accelerator alone. When the impregnating resin material is the above-mentioned epoxy synthetic resin material, any of the well-known, for example, polyethylene-vinyl acetate copolymer (hereinafter, EVA)
), Polyvinyl acetate (hereinafter abbreviated as PVB), polyvinyl formal, or polyvinyl butyral such as polyvinyl butyral.

The polyvinyl butyral exemplified here has a degree of polymerization of several tens to several hundreds, which seems to be preferable in terms of treatment. The promoter protective layer 4 using polyvinyl butyral is formed by dissolving the polyvinyl butyral to be used in a solvent suitable for the solution, and applying a known appropriate method such as a dipping method, a coating method, or a dropping method. The processed base material 2 is used and then dried and formed. The adhesive layer 5 is formed using only an epoxy resin, and is different from the adhesive layer 6 according to the conventional example shown in FIG. 4 only in that it does not contain a curing accelerator. The adhesive layer 5 is formed on the treated base material 2 via the accelerator protective layer 4 that has been dried.

Even in the case of the electric insulating layer using the mica tape 1, the wound layer using the mica tape 1 is impregnated with the impregnating resin material by a vacuum pressure impregnation method, and after the impregnation, the heat curing of the impregnating resin material is performed. Processed. Since the melting point of the polymer material used for the accelerator protective layer 4 is set as described above, it is melted when the impregnating resin material is subjected to the heat curing treatment. When the accelerating agent protective layer 4 is melted, it fuses with the impregnating resin material, and the impregnating resin material is brought into contact with the curing accelerator layer 3 to accelerate the curing. As a result, an electrical insulating layer such as a ground insulating layer having the impregnated resin material cured in the wound layer using the mica tape 1 is formed.

Since the mica tape 1 according to the embodiment of the present invention shown in FIG. 1 has the above-described structure, the curing accelerator layer 3 is smaller than the curing accelerator used in the curing accelerator layer 3. It will be covered by the accelerator protective layer 4 which has only reactivity. Therefore, the epoxy resin forming the adhesive layer 5 does not come into contact with the curing accelerator forming the curing accelerator layer 3 during storage of the mica tape 1. For this reason, the pot life can be greatly extended, and the necessity of storing at a low temperature is eliminated.

Also, when the wound layer using the mica tape 1 is impregnated with the epoxy synthetic resin material, the epoxy synthetic resin material does not come into contact with the curing accelerator. Does not undergo a curing reaction by a curing accelerator. This eliminates the problem that the viscosity of the epoxy-based synthetic resin material increases during the impregnation process due to the curing reaction, so that even in the case of an electrically insulating layer having a large thickness, the entire wound layer has epoxy. It becomes easy to impregnate the synthetic resin material. In addition, it is substantially unnecessary to consider the reactivity of the curing accelerator, and the impregnation temperature can be set freely within a range lower than the melting point of the polymer material used for the accelerator protective layer 4. become.

That is, in the case of the wound layer using the mica tape 1, the impregnation temperature can be set with emphasis on the impregnation property of the epoxy-based synthetic resin material. Can be easily impregnated with an epoxy-based synthetic resin material. Due to these features, in the electric insulating layer using the mica tape 1, the synthetic resin material is satisfactorily impregnated into the entire wound layer, so that the electric insulating performance and the long-term reliability thereof can be improved.

In the above description, the hardening accelerator layer 3 of the treated base material 2 has been described as being formed only by the hardening accelerator. However, the present invention is not limited to this. It may be formed as a mixture with a polymer material for the protective layer 4. In the above description, the adhesive layer 5 has been described as being formed using a material different from the polymer material for the promoter protective layer 4, but the present invention is not limited to this. Numeral 5 may be formed by using a polymer material for the accelerator protective layer 4. This can reduce the number of types of polymer materials to be prepared at the time of manufacturing the mica tape, which is effective in reducing the manufacturing cost of the mica tape.

Furthermore, in the above description, the mica sheet used for the mica sheet layer 7 is bonded to the treated substrate 2 using the adhesive layer 5, but the present invention is not limited to this. For example, it may be configured to be bonded to the treated substrate 2 by the accelerator protective layer 3 before curing.

[0024]

Embodiments of the present invention will be described below with reference to the drawings. In the following description of this section, the same parts as those of the mica tape of the embodiment of the present invention shown in FIG. 1 and the conventional mica tape shown in FIG. , The description of which is omitted.

Embodiment 1 FIGS. 2A and 2B are drawings schematically showing a mica tape according to an embodiment of the present invention, wherein FIG. 2A is a sectional view, and FIG. FIG.
It is BB sectional drawing in (a). In FIG. 2, 1
A is a substrate (hereinafter abbreviated as a treated substrate) 2A which has been treated with a curing accelerator, an accelerator protective layer 4A,
This is a mica tape including a mica sheet layer 7 and an adhesive layer 5A. The treated base material 2A is formed by treating the base material 8 with a curing accelerator to form a curing accelerator layer 3A. This curing accelerator layer 3A dissolves zinc naphthenate (manufactured by HC Stark) as a metal salt in an EVA solution obtained by dissolving evaprene 450 (manufactured by Bayer) as EVA in toluene. The substrate 8 is formed by immersing the base material 8 in this curing accelerator solution and then drying it using the curing accelerator solution prepared as described above.

The accelerator protective layer 4A is formed by using an EVA solution obtained by dissolving levaprene 450 in toluene, immersing the treated substrate 2A in this EVA solution, and then drying. The adhesive layer 5A is formed by using a resin solution obtained by dissolving the aforementioned epoxy resin material in xylene, and dropping this resin solution onto the treated base material 2A covered with the promoter protective layer 4A. . That is, the mica tape 1A
The mica sheet is adhered to the treated substrate 2A covered with the promoter protective layer 4A while dropping the resin solution, and dried to form the mica sheet layer 7. Note that E
It is preferable that the VA solution is integrally formed with the one for the curing accelerator layer 3A and the one for the accelerator protective layer 4A because the number of manufacturing steps of the mica tape 1A can be reduced.

A characteristic configuration of the mica tape 1A according to the first embodiment is that a curing accelerator is applied as a mixture with EVA which is a polymer material used for the accelerator protective layer 4A. This makes it possible to further suppress the influence of the curing accelerator during the impregnation process, while maintaining the features of the mica tape 1 described in the section of the embodiment of the invention as it is.

Embodiment 2 FIG. 3 is a sectional view schematically showing a mica tape according to an embodiment of the present invention corresponding to claims 1 to 4. In FIG. 3, 1B is a mica tape composed of a base material (hereinafter abbreviated as a treated base material) 2B treated with a curing accelerator, an accelerator protective layer 4B, and a mica sheet layer 7. . The treated substrate 2B has a curing accelerator layer (not shown) formed by treating the substrate 8 with a curing accelerator. The cured accelerator layer of the treated base material 2B is obtained by dissolving PVA Sekilek B (manufactured by Sekisui Chemical Co., Ltd.) in ethylcellosolve and adding 2-methyl-imidazoles to a PVA solution. 4
-It is formed by using a curing accelerator solution prepared by dissolving ethyl imidazole, dipping the substrate 8 in the curing accelerator solution, and then drying.

The promoter protective layer 4B is made of a PVA solution obtained by dissolving Sekilek B in ethyl cellosolve.
The solution is applied to the treated substrate 2B by a dropping method so as to cover the entire surface of the treated substrate 2B. Then, the mica sheet is attached to the treated substrate 2B with the PVA solution at the same time as the step of dropping the PVA solution, and the mica sheet layer 7 is formed. That is, the promoter protective layer 4B
Will also serve as an adhesive layer for the mica sheet. After the completion of the PVA solution dropping process and the mica sheet bonding process, the PVA solution is dried, whereby the promoter protective layer 4B and the mica sheet layer 7 are completed at the same time, and the mica tape 1B is obtained. It is preferable that the PVA solution is integrally formed with the one for the curing accelerator layer and the one for the accelerator protective layer 4B because the number of manufacturing steps of the mica tape 1B can be reduced.

The mica tape 1B according to the second embodiment is similar to the mica tape 1A according to the first embodiment in that a curing accelerator is mixed with a polymer material used in the curing accelerator layer (in the case of the second embodiment, PVA). Since the mica tape 1A is applied as a body, it has the same features as the mica tape 1A. In addition to this, a characteristic configuration of the mica tape 1B according to the second embodiment is that the promoter protective layer 4B also functions as an adhesive layer for a mica sheet. This makes it possible to reduce the number of types of polymer materials to be prepared when manufacturing the mica tape 1B, and to reduce the number of manufacturing steps, thereby further reducing the manufacturing cost of the mica tape 1B. ing.

[0031]

The mica tape according to the present invention has the following effects by adopting the configuration described in the section of the means for solving the above problems. With the configuration according to the item (1) of the means for solving the above problems, the curing accelerator is covered with a polymer material having a small reactivity with the curing accelerator. The time is greatly extended, making it easier to handle storage. Further, since the impregnating property of the impregnating resin material with respect to the mica tape wound layer can be improved, the electric insulation performance and long-term reliability of the electric insulating layer using the mica tape can be improved. In addition, by adopting the configuration according to the item (2) of the means for solving the above problems, the effect of the curing accelerator during the impregnation process can be further suppressed, and the effect of the item is further increased. It is possible to do. In addition, by adopting the configuration according to the item (3) of the means for solving the above problems, it is possible to reduce the number of types of polymer materials prepared at the time of producing the mica tape, and to reduce the effects of the above items. In addition, the production cost of mica tape can be reduced.

[0032] By adopting the constitution according to item (4) of the means for solving the above-mentioned problems, the type of the polymer material to be prepared at the time of producing the mica tape is reduced and the number of production steps is reduced. By being able to
The manufacturing cost of the mica tape can be further reduced while obtaining the effects of the above items.

[Brief description of the drawings]

FIG. 1 is a drawing schematically showing a mica tape according to an example of an embodiment of the present invention, where (a) is a cross-sectional view and (b)
Is a sectional view taken along the line AA in FIG.

FIGS. 2A and 2B schematically show a mica tape according to an embodiment of the present invention corresponding to claims 1 and 2, wherein FIG. 2A is a cross-sectional view thereof, and FIG. Sectional view

FIG. 3 is a sectional view schematically showing a mica tape according to an embodiment of the present invention corresponding to claims 1 to 4;

FIG. 4 is a cross-sectional view schematically showing a conventional mica tape.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Mica tape 2 Treated base material 3 Hardening accelerator layer 4 Accelerator protective layer 5 Adhesive layer 7 Mica sheet layer 8 Base material

Claims (4)

[Claims] 1. A base material which is formed into a tape shape by using a fiber material made of an electric insulating material and which is treated with a hardening accelerator for accelerating a reaction of a resin material for impregnation, An accelerator protective layer covering from the outside of the layer, comprising a mica sheet bonded to the substrate via an accelerator protective layer using an adhesive, the polymer material used for the accelerator protective layer is It has a melting point higher than the temperature at the time of impregnation of the impregnating resin material and lower than the curing temperature of the impregnating resin material, has compatibility with the impregnating resin material, and has a small reaction with the curing accelerator alone. A mica tape characterized by having properties. 2. The mica tape according to claim 1, wherein the base material is a mixture of the curing accelerator and the polymer material used for the accelerator protective layer to form a curing accelerator layer. Mica tape characterized by the following. 3. The mica tape according to claim 1, wherein the adhesive for bonding the mica sheet to the base material is a polymer material used for the promoter protective layer. And mica tape. 4. The mica tape according to claim 1, wherein the mica sheet is bonded to a substrate by the accelerator protective layer before curing.