JP2002093257A - Mica substrate sheet body and insulated coil - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide mica insulating material with efficient heat dissipation, which is difficult to break when wound and easy to manufacture, especially as material for miniaturized coils with high performance by using woven glass fabric as backing material, and to provide an insulated coil in which the mica insulating material is used. SOLUTION: In a mica substrate sheet body comprising backing material, a mica layer containing mica, an adhesive layer for joining the backing material and the mica layer, and a heat conductive layer, containing mineral powder with higher heat conductivity than mica, woven glass fabric is used as the backing material. the woven glass fabric being filled with filler containing mineral powder, or the heat conduction layer is provided for the mica layer. The above-mentioned purpose can be achieved by the coil insulated with the sheet.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mica substrate sheet used for forming an insulating layer of a coil, particularly a high voltage coil, in an electric appliance, particularly an electric device such as a generator, and an insulating coil using the same. About.

[0002]

2. Description of the Related Art In order to insulate a bundle of windings of a coil used for a rotor or a stator in an electric device such as a generator, a mica material having good insulating properties has been used.
In this case, if insulating paper made of mica as a main component is used for insulating the coil, the thermal conductivity of the insulating paper is poor,
Since it is difficult to dissipate the heat generated by the coil during operation, the coil is likely to store heat, adversely affecting the electrical characteristics of the coil, and has a problem in maintaining the performance as an electric device. In particular, recently, there has been a demand for the appearance of small-sized and high-performance electric devices, and the problem is increasing. In order to solve this problem, as described in JP-B-56-38006, a mica base sheet containing an inorganic powder having better heat conductivity than mica when mixing mica and synthetic fiber fibrids is used. Is wound around a coil and then impregnated with a resin, or as described in JP-A-63-110929, an insulating tape in which a mica tape is adhered to a glass fiber woven fabric with a polyethylene glycol terephthalate film is wound around the coil. After that, it has been proposed to impregnate a resin containing an inorganic powder having better thermal conductivity than mica, and to improve the thermal conductivity of the insulating layer in any case.

[0003] However, in the former, if the particle size of the inorganic powder having better thermal conductivity than mica is smaller than 30 µm, the inorganic powder falls off from the paper net when forming with synthetic fiber fibrid and mica, and the papermaking yield is poor. Therefore, the particle size is limited to 30 μm to 100 μm, it is not possible to sufficiently fill a small gap between the mixed layer of synthetic fiber fibrid and mica, and the heat conductivity is sufficiently improved by the presence of air in the gap. There was a problem that can not be. The latter has a particle size of 0.1 μm
On the contrary, although it is small as ~ 15 μm, since it is impregnated with the resin, its flow resistance that penetrates into the gap of the insulating tape is large, especially only the resin penetrates into the fine gap inside and the inorganic particles are on the surface side. The impregnated layer tends to be uneven because it is caught and cannot be penetrated deeply.The impregnated layer tends to be non-uniform, and it takes a long time to penetrate, resulting in poor productivity. Usually, the side that provides the insulating material and the side that uses it are different, so imposing a burden on the user side is not preferable in terms of productivity.On the other hand, the supplier of the insulating material and the impregnating resin Since the suppliers are often different, there is a problem in that performing the work on either side imposes an extra burden and impairs productivity.

[0004]

SUMMARY OF THE INVENTION Therefore, Japanese Patent Application No. Hei 7-2
In the specification of Japanese Patent No. 13971, a mica base sheet in which an adhesive layer between a mica layer and a backing material contains an inorganic powder having good thermal conductivity is proposed. When mica tape is used as an insulating material for a coil, the tape is wound obliquely when wound around the coil, so shearing force is applied to the tape and the tape is torn from the side edges. There is
There is a need to increase the so-called end tear resistance, which makes the tearing less likely to occur. If the tape is torn, there is a problem that the winding work is stopped, the work is re-executed, the repair work is performed, and the workability is deteriorated, and the productivity is deteriorated. As a countermeasure, it is conceivable to increase the glass thread of the glass cloth or increase the number of vertical and horizontal threads, but if the thread is too thick, the ratio of the mica substrate sheet in the thickness direction increases, and the If the number of yarns is too large, the penetration of the resin through the backing material will not be performed well, and there will be a problem in the adhesion between the mica layer and the backing material. When wound around the insulating part of the coil, peeling of both occurs,
The winding workability is impaired, the finished product is not good, and a predetermined insulating property may not be obtained. To solve the problem when using such a glass cloth, Japanese Patent Application No.
In the specification of 146661, a mica base sheet and an insulating coil obtained by using a cloth made of, for example, a polyamide or polyester yarn instead of a glass cloth have been proposed. However, these organic materials are expensive. Therefore, there is a problem that the heat resistance is lowered or the heat resistance is lowered. A first object of the present invention is to provide a mica base material having relatively uniform thermal conductivity, relatively uniform heat dissipation, and particularly difficult to store heat when used as an insulating material for a coil, and having high edge crack resistance. An object of the present invention is to provide a sheet-like body and an insulating coil using the same. A second object of the present invention is to provide a mica base sheet which can be obtained at low cost without lowering heat resistance by using glass cloth as a backing material, and an insulating coil using the same. A third object of the present invention is to provide a mica substrate sheet which is particularly suitable for recent miniaturized and high performance coils and an insulating coil using the same. Fourth Embodiment of the Present Invention
An object of the present invention is to improve winding workability and improve productivity when using a mica base sheet in a coil manufacturer. A fifth object of the present invention is to provide an insulating material provider,
An object of the present invention is to provide an impregnating resin provider and a user thereof without significantly changing a conventional production process and without impairing productivity.

[0005] In order to achieve the above object, the present invention provides:
(1) A mica base sheet having a backing material and a mica layer containing mica bonded via an adhesive layer, and having a heat conductive layer containing at least a resin and an inorganic powder having better heat conductivity than mica. Wherein, while using a glass cloth for the backing material, the heat conductive layer is provided on at least one of the mica layer and a filled backing material obtained by filling the glass cloth with a filler containing an inorganic powder,
Further, the filled backing material provides a mica base sheet using a filler having a higher resistance to edge tear than when the components of the heat conductive layer are filled in the glass cloth.
Further, in the present invention, (2) the inorganic powder contained in the filler is mica powder, and the inorganic powder having better thermal conductivity than mica is a random-shaped alumina powder.
(3) The mica base sheet according to (1) or (2), wherein at least the mica layer and the bonding layer contain an inorganic powder having better thermal conductivity than mica. (4) The mica base sheet according to any one of (1) to (3), wherein the inorganic powder having a higher thermal conductivity than the mica contained in the thermal conductive layer has a particle size of 0.1 μm to 50 μm. , (5), the mica layer is composed of mica, 5 to 50 parts by weight of synthetic fiber fibrids with respect to 100 parts by weight of the mica, and 5 with respect to 100 parts by weight of the mica.
(1) to (4), wherein the inorganic powder having good thermal conductivity is contained in the mica layer, and the particle diameter of the inorganic powder having good thermal conductivity to be contained in the mica layer is 5 μm to 50 μm. (6), wherein the ratio of the adhesive layer to the whole of the mica layer, the filled backing material and the adhesive layer is 5 to 15% by weight, and the mica layer and the filled backing material are adhered to each other. The ratio of the heat conductive layer to the whole of the layer and the heat conductive layer is 25 to 55% by weight, and the heat conductive layer
The mica base sheet according to any one of the above (1) to (5), containing an inorganic powder having better thermal conductivity than 5 to 95% by weight of mica, (7), a mica layer, a filled backing material and an adhesive layer. The ratio of the heat conductive layer to the whole of the mica layer, the filling backing material, the adhesive layer and the heat conductive layer is 20 to 50% by weight, and the ratio of the heat conductive layer is 25 to 50% by weight. The layer is composed of an inorganic powder having better thermal conductivity than 65 to 85% by weight of mica, and the mica base sheet according to any one of the above (1) to (6); (9) an insulating coil having an insulating layer formed by a mica substrate sheet and a cured layer of an impregnated resin; (9) an impregnated resin layer containing an inorganic powder having better thermal conductivity than mica;
And (8) an insulating coil in which the particle diameter of the inorganic powder is 0.1 to 15 μm, (10), a mica base sheet in (7), an adhesive layer containing the mica base sheet, An object of the present invention is to provide an insulating coil in which an insulating layer is formed by a thermosetting layer of a heat conductive layer.

The mica substrate sheet of the present invention is a mica layer containing mica, a backing material filled with a backing material containing a filler containing an inorganic powder, and the mica layer and the backing material are joined together. It has an adhesive layer and a heat conductive layer, and at least the heat conductive layer contains an inorganic powder having better heat conductivity than mica, and a glass cloth is used as the backing material. A glass cloth and an organic polymer film may be used in combination. A cloth using a yarn made of polyamide has a higher tensile strength than glass cloth, a large tear resistance, heat resistance, and is preferable as a backing material for a mica base sheet used for a coil of a large generator, etc. Also,
Since the cloth using the yarn made of polyester expands and contracts to some extent, it is strong as a stress and is preferable as a backing material for the mica base sheet used for relatively small coils,
The former has a problem that the cost is higher than that of the glass cloth, and the latter has a problem that the heat resistance is reduced.
Polyolefins and other organic polymer materials have similar problems. Mica substrate sheet using glass cloth as backing material, by improving the end crack resistance,
Although it can be used at a low cost and can make use of its excellent performance such as heat resistance, it is filled with a filler containing an inorganic powder in order to increase its edge crack resistance. If the adhesive layer or the heat conductive layer that bonds the mica layer to the backing material contains an inorganic powder with better thermal conductivity than mica, the crack resistance of the mica base sheet using glass cloth as the backing material Is lower than the crack resistance of only the backing material, but when the above-described heat conductive layer is provided on the backing material filled with the filler, that is, on the filled backing material, when forming the heat conductive layer, In addition, it is possible to prevent the glass cloth from being filled with an inorganic powder having better heat conductivity than mica, and to use a heat conductive layer using an inorganic powder having better heat conductivity than mica because the material is restricted. While the selection range for giving flexibility is narrow, when the glass powder is filled with unrestricted inorganic powder, the selection range for giving flexibility to the filled backing material can be widened, result Would be able to improve the edge tear resistance of above.
Due to this, the filling backing material has more flexibility than when the glass cloth is filled with the components of the heat conductive layer,
End tear resistance can be improved. Further, when the heat conductive layer is provided on the mica layer, the glass cloth is not affected by the heat conduction layer, and the end resistance can be improved rather than reduced.

[0007] The filler to be filled in the glass cloth contains an inorganic powder capable of imparting the above-mentioned flexibility and improving end crack resistance. Examples of the inorganic powder include mica powder, talc, silica and boron nitride. And spherical alumina, and at least one of them can be used. Even with the same alumina, when the alumina of random shape is filled in glass cloth, the end crack resistance decreases,
In the case of spherical alumina, the decrease is small, but it is considered that the shape of particles penetrating into the glass cloth fiber affects end crack resistance. The mica powder may be any of natural hard and soft fired and unfired mica, peeled mica, and synthetic mica. As the inorganic powder, it is preferable that the inorganic powder can be mixed with an adhesive, and the mixture can be applied by an application means such as a roll coater.
The particle size may be, for example, in the range of 0.1 μm to 50 μm, but may be a glass cloth impregnated with a dispersion of inorganic powder alone or other components such as resin dispersed in a solvent. The ratio between the adhesive and the inorganic powder and the ratio between the resin and the inorganic powder are preferably 1: 2 to 1:19 in terms of solid content ratio (weight ratio), and a solvent may be added when applying. The filling amount of the filler containing the solid content of the inorganic powder and the adhesive or the resin with respect to the glass cloth is preferably 30 to 150% by weight based on the total weight including the glass cloth. When the respective component ratios and the filling amounts are within the above ranges, the above-mentioned end crack resistance is advantageous for the effect of improvement. As the adhesive or resin, for example, an epoxy resin, a polyester resin, a silicone resin, or the like is used.

In the mica substrate sheet of the present invention, the heat conduction layer is always selectively heat-resistant to the adhesive layer for joining the mica-containing mica layer and the backing material. Although the inorganic powder is contained, the inorganic powder can be finely and uniformly contained in the adhesive by a milling means such as a roll mill in this manner, and the coating layer can be formed to have an arbitrary uniform thickness. The composition of the heat conductive layer and the adhesive layer becomes uniform, and the thickness and the heat conductivity can be made uniform. When the heat conductive layer and the adhesive layer having uniform heat conductivity are interposed in this way, heat is radiated relatively uniformly in each part of the layer through this layer, and the entire heat can be promoted. The inorganic powder having a higher thermal conductivity than the mica refers to a thermal conductivity of the mica of about 0.6 W / m.
-It is only necessary to be larger than K, and a granular material is preferable from the viewpoint of its filling property. Specifically, for example, boron nitride (thermal conductivity of about 84 W / m · K; hereinafter, thermal conductivity in parentheses), alumina (aluminum oxide) (about 33 W / m · K), magnesium oxide (about 38 W / m · K) ), Beryllium oxide (about 3
77 W / mK), silicon carbide (about 42 W / mK), or a mixture of two or more thereof. The particle size of the inorganic powder and the compounding amount thereof can be mixed with the adhesive, and the mixture can be applied by a coating means such as a roll coater, and if the adhesive layer does not impair the function of the adhesive. Good, but the particle size is, for example, 0.1.
Those having a range of 1 μm to 50 μm can be exemplified. The content of the mica base sheet varies depending on the type of the mica base sheet. The ratio of the mica layer, the filled backing material, and the adhesive layer to the entire adhesive layer is 5 to 15% by weight. In the case of a so-called dry mica tape in which the ratio of the heat conductive layer to the whole of the adhesive layer and the heat conductive layer is 25 to 55% by weight, the ratio to the whole of the adhesive layer is 0 to 70% by weight. The ratio of the mica layer, the filled backing material, and the adhesive layer to the whole of the adhesive layer is 25 to 50% by weight, and the mica layer, the filled backing material, the adhesive layer, In the case of a so-called prepreg mica tape in which the ratio of the heat conductive layer to the whole layer is 20 to 50% by weight, the ratio to the whole adhesive layer is 0 to 40% by weight, and the ratio to the whole heat conductive layer is 65. ~
85% by weight is preferred. If the amount in the heat conductive layer is less than this, the thermal conductivity is not so much improved, and if the amount in the adhesive layer is more than this, the effect as an adhesive may not be sufficient. As an adhesive that can be used for the adhesive layer and the heat conductive layer, for example, an epoxy resin, a polyester resin, a silicone resin, or the like is used. It is preferred that the resin be thermally cured by infrared irradiation or the like.

The mica layer containing mica used in the present invention may be a natural soft or hard mica, or may be a synthetic mica. These forms may be peeled mica or laminated mica. These may be used alone or in combination. It can be used, mica alone or other materials described below, and further dispersed in water together with at least one kind of dispersant such as polyethylene oxide, and the dispersion is formed into a sheet by using a fourdrinier paper machine or the like. Is preferred. In addition,
The aggregated mica is a composite of synthetic mica and natural mica. For natural mica, hard or soft mica is beaten to form fine pieces (for example, about 0.1 to 10 μm thick,
A size of 0.005 to 5 mm ² ) is assembled, and among them, calcined mica is preferably used. The mica of this calcined aggregate mica is obtained by treating the hard mica that has been calcined with an acid and an alkali, and then beating it into fine flakes. It causes wrinkles and enlarges the cleavage layer, so that the sedimentation speed is slow, and it is easy to get entangled with the synthetic fiber fibrid described later, so that when it is made into a sheet, it should have excellent uniform strength of formation. Can be. The mica layer is preferably mixed with an inorganic powder having better thermal conductivity than the mica. The amount of the inorganic powder is preferably 5 to 50 parts by weight per 100 parts by weight of the mica. The effect of improving the conductivity as compared with the case of using mica alone is small, and if it is more than this, the mechanical strength tends to be reduced when the sheet is formed. In addition, the particle diameter of the inorganic powder is preferably 5 μm or more and 50 μm or less.
There is a tendency for the yield to deteriorate due to falling off from the paper net,
On the other hand, if it is too large, the mica layer may be reduced in strength when formed into a sheet. In addition, it is preferable to mix a synthetic fiber fibrid in the mica layer, since it is possible to wrap the mica and the above-mentioned inorganic powder so that the mica and the above-mentioned inorganic powder can be entangled with each other when the paper is made. If it is too much, the thermal conductivity of the mica layer is reduced, so that the mica layer can be maintained in a sheet shape when formed by papermaking and can be bonded to the backing material or the filling backing material with an adhesive, and the compounding amount is mica. 5 to 50 parts by weight per 100 parts by weight is preferred.

[0010] One surface of the backing material and the mica layer are joined by the adhesive layer, and then the other surface of the backing material is filled with the above-mentioned filler to form a filled backing material, or The filled backing material filled by filling or dipping and the mica layer are joined by an adhesive layer applied and formed on the filled backing material, and in any case, the heat conductive layer is filled with one or both of the filled backing material and the mica layer. Thus, a mica base sheet is obtained. The mica base material sheet is cut into a tape shape as it is, and in the case of the above-mentioned dry mica tape, the tape is wound around the insulating portion of the coil, vacuum-treated to release air, and then the wound layer is formed. The insulating layer can be formed by impregnating a resin and hardening with a hot air in the case of a small coil, and by heating and pressurizing in the case of a large coil. As the impregnating resin, for example, an epoxy-acid anhydride resin, a polyester resin, a silicone resin or the like is used. The thermal conductivity of these resins is better than air, and generally worse than mica, but at least the adhesive layer that joins the backing material and the mica layer and at least the heat conductive layer of the heat conductive layer are inorganic powders with better thermal conductivity than mica. , Heat conduction that dissipates heat generated by the operation of the coil to the outside by promoting good heat conductivity and uniform heat conductivity can be promoted, and heat dissipation can be promoted. As described above, the mica base sheet can be supplied without impregnating the resin, but in the case of the prepreg mica tape described above, the resin of the adhesive layer and the heat conductive layer should be semi-cured. In that case, after being wound around the insulating part of the coil, it can be cured by heating and pressure without impregnation with resin, or by heating and pressure curing after vacuum treatment as above. By curing the resin, an insulating layer can be formed.

In the case of dry mica tape, the impregnated resin may contain an inorganic powder having better thermal conductivity than the above mica, and in this case, the particle diameter of the inorganic powder is 0.1 μm to 15 μm. It is preferable to reduce the flow resistance for impregnating the mixture and to increase the dielectric breakdown voltage, and the mixing ratio with the resin is preferably 5 to 50% by weight based on the total solid content of both.
If the amount is less than this, the effect of improving the thermal conductivity is small, and if it is more than this, the viscosity of the impregnated resin liquid tends to increase and the impregnating property tends to deteriorate.

When the resin is impregnated in a semi-cured state into the mica substrate sheet, or when the mica substrate sheet wound in a coil is impregnated with the resin, the adhesive layer must be formed on the heat conductive layer. Optionally, contains an inorganic powder with better thermal conductivity than mica, but its thickness is thicker if the inorganic powder is not contained in the mica layer, impregnated resin,
When it is contained, it is preferable to make it thin.

The mica substrate sheet of the present invention and the insulated coil using the same are obtained in this manner. By adding an inorganic powder having a higher thermal conductivity than mica to the heat conductive layer and the adhesive layer, The particle size of the inorganic powder can be widened, eliminating the need to select the particle size accordingly,
The mixing means with the adhesive can also be easily performed, and the composition and thickness of the heat conductive layer and the adhesive layer are not required because, for example, the resin does not need to be penetrated into the gap as in the case of impregnating the resin with the gap in the mica layer. It has the effect of promoting heat dissipation by improving thermal conductivity, and also contains an inorganic powder with better thermal conductivity than mica in the mica layer and its impregnated resin. By doing so, the heat radiation effect can be increased,
It is possible to satisfy the recent demand for an insulating material for a small-sized and high-performance electric device, particularly for a high-voltage coil. As described above, if the insulation characteristics of the electric device can be maintained at a high level, the operating characteristics of the electric device can be maintained. For this reason, in the above invention, the "mica substrate sheet" may be a "mica substrate insulation sheet for coil", and the "coil" may be "small coil", "small size and high performance". Coil ". In these inventions, the method for manufacturing these and an insulating coil (small insulated coil or downsized / high performance insulated coil)
These can be applied mutatis mutandis. Further, the mica substrate sheet of the present invention can be used as a heat-resistant electric insulating heat-radiating spacer, for example, as a material having improved heat radiation in a power transistor heat-radiating insulating plate or the like.

[0014]

Next, an embodiment of the present invention will be described. As a backing material, a glass cloth having a thickness of 0.03 mm to 0.08 mm using a glass fiber as a warp and a weft is used, and the ratio of the adhesive layer to the entire mica layer, the filled backing material and the adhesive layer is 7%. About 9% by weight, and the ratio of the heat conductive layer to the whole of the mica layer, the filling backing material, the adhesive layer and the heat conductive layer is 35 to 45% by weight, and the heat conductive layer is 80 to 90% by weight.
The dry mica tape containing 90% by weight of alumina, the ratio of the mica layer, the filled backing material and the adhesive layer to the whole adhesive layer is 30 to 40% by weight, and the mica layer, the filled backing material, the adhesive layer and the heat conduction The proportion of the heat conductive layer in the whole layer is 30 to 40% by weight, and the heat conductive layer makes a prepreg mica tape containing 70 to 80% by weight of alumina. At that time, the following three types of laminated mica base foils were used for the mica layer, and the heat conductive layer and the adhesive layer were epoxy-based.
Using an adhesive mainly composed of an amine-based thermosetting resin, alumina powder used by mixing with the adhesive has a particle size of about 0.1 μm to 30 μm, and an adhesive layer comprises a mica layer and a backing material. The backing material is layered on the lower side and applied by a roll coater from the backing material side to form a coating material.Then, the filling material liquid obtained by adding a solvent containing mica powder and an adhesive or a resin to the backing material side is applied and dried. Then, a thermal conductive layer is formed on the filled backing material side or the mica layer by coating. As the type of the mica-assembled base material foil, only mica-containing mica layer containing calcined mica alone or 10 to 30 parts by weight of aromatic polyamide fibrite (freeness 60 ° SR) per 100 parts by weight of calcined mica Alternatively, 20 to 40 parts by weight of alumina (particle size: about 20 μm to 40 μm) is dispersed in water with respect to 100 parts by weight of the calcined aggregated mica, and the resulting dispersion is formed by a fourdrinier paper machine. Three types of laminated mica substrate foils corresponding to each of 08 to 0.16 mm were produced. In this way, three types of dry mica tapes and three types of prepreg mica tapes are produced, wound on the coil conductor three times by half (winding while overlapping half the width), and then the former three types About the dry mica tape, the degree of vacuum is about 1 mmHg,
After drying at a temperature of about 90 ° C to remove volatile components such as moisture,
The impregnating resin composition mainly composed of an epoxy-anhydride thermosetting resin is vacuum impregnated, and the temperature is gradually increased from 100 ° C. to 180 ° C. to completely cure the resin. The temperature was gradually increased from 100 ° C. to 180 ° C., and the resin was completely cured, thereby producing respective insulating coils. In this way, any dry mica tape,
Both the prepreg mica tape and glass cloth are filled with filler, so the resistance to tearing is large, the tape does not break during winding work, and the insulating coil is generated in the coil conductor through the adhesive layer The heat is dissipated, and the adhesive layer has a uniform composition and a uniform thickness, so that the heat dissipating efficiency is good and the adhesion can be promoted.

[0015]

Next, an embodiment of the present invention will be described. Example 1 Glass cloth M0.04 manufactured by Arisawa Seisakusho Co., Ltd.
(60 lines / inch (D450 1/0), 34 lines /
An inch (D900 1/0) 0.046 mm thick glass cloth is used. 100 parts of the calcined aggregated mica was dispersed in water, and the resulting dispersion was paper-formed with a fourdrinier paper machine to produce a laminated mica base foil having a mica layer thickness of 0.08 mm. The glass cloth is laminated with the laminated mica substrate foil on the upper side, and an adhesive (Epicoat 828 (epoxy resin manufactured by Yuka Shell Epoxy)) containing an epoxy-amine-based thermosetting resin as a main component from the glass cloth side 10
0 parts by weight and ₃ parts by weight of BF ₃ monoethylamine)
Is applied by a roll coater and dried to form an adhesive layer (adhesive layer (solid content) in the entire mica layer, backing material and adhesive layer)
Is 8% by weight), and mica powder (A2000, manufactured by Nippon Mica Seisakusho Co., Ltd.) is added to the above adhesive on a glass cloth side at a solid content weight ratio of 1: 4, and a solvent (toluene / methyl ethyl ketone = 1: 1) is added to prepare a filling body fluid (viscosity of 80 poise), which is applied by a roll coater and dried to form a filling backing material. At this time, mica powder coating amount (g / m ²⁾ as shown in Table 1, in 0~25g / m ^2, to form a filled backing for each case was increased 5 g / m ² at a time. After this,
The alumina-containing adhesive obtained by mixing alumina AL-43-L (aluminum oxide manufactured by Showa Denko KK (alumina having a random shape with an average particle size of 1 μm)) to the above adhesive so as to be 85% by weight of the total solid content was used. Apply to the filling backing material side,
After drying, a heat conductive layer was formed. At this time, as shown in Table 1, alumina was applied at a target of 160 g / m ² , and a heat conductive layer was formed in each case. Alumina coating amount is 2
At 10 g / m ² , the ratio of the heat conductive layer to the whole of the mica layer, the filling backing material, the adhesive layer, and the heat conductive layer is 40% by weight.
become. The dry mica tape obtained in this manner was wound half a time on a conductor three times, and then the degree of vacuum was about 1 mmHg.
After drying at a temperature of about 90 ° C to remove volatile components such as moisture,
100 parts by weight of an impregnating resin composition (Epicoat 828 (epoxy resin manufactured by Yuka Shell Epoxy Co., Ltd.)) containing an epoxy-acid anhydride-based thermosetting resin as a main component and Kayahard MCD
(An acid anhydride manufactured by Nippon Kayaku Co., Ltd.), an impregnating resin composition containing 90 parts by weight as a main component, and
The temperature was gradually increased to 0 ° C. to completely cure the resin, and an insulating coil having an insulating layer formed on a conductor was produced.

In Table 1, dry mica tape No. 3-7
(Alumina-containing mica base sheet with filled backing material
Body) and backing material without filling material
And the above-mentioned alumina-containing adhesive directly on the glass cloth side.
Dry Mykate formed in the same way except that it was clothed
No. 1, 2 (Mica base sheet with unfilled backing material)
Mica substrate containing alumina
G), the crack resistance of the dry mica tape
Table 1 shows the results measured together with the thickness of the sample. Also, conductor
After cutting off the insulating layer formed on and polishing the surface
As for the insulating layer, the thermal conductivity is set to 0.3 to 0.5 W / m ·
K. In addition, the end crack resistance
Cut the tape into 15mm width and smell each test
To make five test pieces each, and use the Shimadzu Corporation
The measurement was performed using an AGS-500A tester. At the time of the test
The speed of loading on the specimen was 50 mm / min.
The thermal conductivity is calculated from the amount of evaporation of the low-boiling liquid in the steady state.
Method of determining the amount of overheating (thermal conductivity measurement made by Shibayama Scientific Instruments)
Fixed device). From the results in Table 1,
Mica powder application amount 20g / m^TwoAbove (at least 20g
/ M ^Two, The same applies to the following.)
, The tear resistance is so low that it hinders the winding operation
It turns out that it does not. By expanding the range, 10 g / m
^TwoOr more or 15 g / m^TwoIt may be.

[0017]

[Table 1]

Example 2 The procedure of Example 1 was repeated except that 100 parts by weight of calcined aggregate mica and 20 parts by weight of aromatic polyamide fibrite (freeness 60 ° SR) were used instead of 100 parts by weight of calcined aggregate mica. Then, a dry mica tape and an insulated coil were prepared and subjected to the same test as in Example 1. As a result, the results shown in Table 2 were obtained.

[0019]

[Table 2]

EXAMPLE 3 In Example 1, 100 parts by weight of calcined mica, 20 parts by weight of aromatic polyamide fibrite (freeness 60 ° SR) and 100 parts by weight of mica were used in place of 100 parts of calcined mica. Alumina similar to (average particle size 30μm) 3
A dry mica tape and an insulating coil were prepared in the same manner except that 0 parts by weight were used, and a test was conducted in the same manner as in Example 1. As a result, the results shown in Table 3 were obtained.

[0021]

[Table 3]

Examples 4 to 6 In Examples 1 to 3, the ratio of the adhesive layer (solid content) to the whole of the mica layer, the filled backing material and the adhesive layer was 35% by weight.
A heat conductive layer was formed using an alumina-containing adhesive obtained by mixing alumina AL-43-L (aluminum oxide manufactured by Showa Denko KK (average particle size: 1 μm)) so as to be 75% by weight of the total solid content. Examples 4 to 6 (Examples 1 to 3) were performed in the same manner except that the ratio of the heat conductive layer to the whole of the mica layer, the filled backing material, the adhesive layer, and the heat conductive layer was 35% by weight.
Prepreg mica tape was wound around a conductor in the same manner as in Example 1, and the temperature was gradually increased from 100 ° C. to 180 ° C. to completely cure the resin, and an insulating layer was formed on the conductor. Make an insulated coil. The obtained prepreg mica tape (alumina-containing mica base sheet using a filling backing material) and the above-mentioned alumina-containing adhesive are directly applied to the glass cloth side as it is without filling the filling material into the backing material. A prepreg mica tape (mica base sheet using an unfilled backing material, alumina-containing mica base sheet using an unfilled backing material) and an insulating coil were formed in the same manner as in Example 1 except for the following. As a result, the results shown in Table 4 (Example 4), Table 5 (Example 5), and Table 6 (Example 6) were obtained.

[0023]

[Table 4]

[0024]

[Table 5]

[0025]

[Table 6]

Example 7 In Example 1, mica powder A2000 was replaced with nitrogen
A drive made in the same manner except that boron boride was used.
Imai mica tape, including alumina with a filling backing
Mica with mica base sheet or unfilled backing material
Substrate sheet, unfilled backing material
Dry mica tape of the base material sheet
Insulated coil using dry mica tape
When the test was carried out in the same manner as in Example 1, the crack resistance and dry mica
The thickness of the tape was as shown in Table 2. So
In other respects, the result according to the first embodiment is obtained. This place
In the case, the coating amount of boron nitride is 25 g / m^TwoAbove is preferred
Is 10 g / m ^TwoOr more or 15 g / m^TwoOr more
No. In the above Examples 2 to 6, the mica flour A2000
Instead, do the same except that boron nitride was used.
Examples 2 to 6 were also applied to the produced dry mica tape.
And the results according to Table 7 and Table 7 are obtained.

[0027]

[Table 7]

Example 8 A dry mica tape prepared in the same manner as in Example 1 except that the heat conductive layer was not formed on the filled backing material side but was formed on the mica layer side, that is, an alumina-containing mica using the filled backing material Substrate sheet (mica layer / filler powder to resin ratio 4: 1 by weight), mica substrate sheet with unfilled backing material, alumina-containing mica substrate with unfilled backing material Each dry mica tape in sheet form,
Further, when the insulating coil using these dry mica tapes was tested in the same manner as in Example 1, the end tear resistance and the thickness of the dry mica tape were as shown in Table 3. In other respects, a result similar to that of the first embodiment is obtained. In this case, good crack resistance can be obtained irrespective of the amount of alumina applied, but from the viewpoint of thermal conductivity, the amount of alumina applied is preferably 25 to 55% by weight of the weight of the base sheet. In the above Examples 2 to 7, dry mica tapes prepared in the same manner except that boron nitride was used instead of mica powder A2000 were also used.
And the results according to Table 8 are obtained.

[0029]

[Table 8]

Reference Example In Example 1, the amount of the inorganic powder in the filling body liquid was as shown in Table 4.
And the coating amount is as shown in Table 4.
Table 9 shows the results of measuring the end tear resistance in the same manner as in Example 1 for the mica base sheet formed in accordance with this except that the heat conductive layer was not provided.

[0031]

[Table 9]

From the results shown in Table 8, when the heat conductive layer is formed on the mica layer side, the edge crack resistance can be made larger than that obtained by bonding the mica layer to the glass cloth with the adhesive layer. Also, from the results of Tables 1 and 7, when the heat conductive layer is formed on the side of the filled backing material, the end crack resistance is lower than that obtained by bonding the mica layer to the glass cloth with the adhesive layer. When the filler containing mica powder is filled, it can be seen that the degree of the decrease decreases as the amount of application increases. From the results in Table 9,
Powders other than random-shaped alumina and silicon carbide do not reduce end cracking resistance, and some of them can be improved on the contrary.Inorganic powders that can improve end cracking resistance can be used. It is possible to obtain a mica base sheet having excellent resistance and thermal conductivity and an insulating layer.

[0033]

According to the present invention, a heat conductive layer is provided, and a glass cloth is used as a backing material in a mica base sheet containing an inorganic powder having a higher heat conductivity than mica. Since the filling body was filled, and the filling backing material was formed using a filling body having a higher end crack resistance than when the components of the heat conductive layer were filled into the glass cloth,
For example, it is possible to reduce the possibility that the mica base sheet is cut during a winding operation when the mica base sheet is mounted on a coil or the like, thereby improving the productivity of the mounting. In addition, heat conductivity is relatively uniform, heat dissipation is relatively uniform, and furthermore, heat dissipation by heat conduction is more rapid by including an inorganic powder having better heat conductivity than mica in the adhesive layer and mica layer. In particular, it is difficult to store heat when used as an insulating material for coils, and is particularly suitable for recent miniaturized, high-performance coils, and uses a relatively inexpensive glass cloth for the backing material. A mica base sheet can be provided. In addition, among the mica base sheet materials, the insulating coil which is impregnated with resin using dry mica tape and thermally cured, or the insulating coil which is thermally cured using prepreg mica tape, has good heat dissipation and operates well. In particular, in the former case, the impregnating resin contains an inorganic powder having better thermal conductivity than mica, so that its heat dissipation can be further improved, and in particular, it meets the recent demand for miniaturization and high performance. An insulated coil can be provided. In addition, it is possible to prevent the productivity from being impaired by the insulating material provider, the impregnating resin provider, and these users without significantly changing the conventional production process.

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Claims (10)

[Claims] 1. A mica base sheet having a backing material and a mica layer containing mica bonded thereto via an adhesive layer, and having a heat conductive layer containing at least a resin and an inorganic powder having better heat conductivity than mica. A glass cloth as the backing material, and the heat conductive layer is provided on at least one of the mica layer and the filled backing material obtained by filling the glass cloth with a filler containing an inorganic powder. And a mica base sheet using a filler whose backing material has a higher resistance to cleaving than when the glass cloth is filled with the components of the heat conductive layer. 2. The mica base sheet according to claim 1, wherein the inorganic powder contained in the filler is mica powder, and the inorganic powder having better thermal conductivity than mica is a random-shaped alumina powder. 3. The mica substrate sheet according to claim 1, wherein at least the adhesive layer of the mica layer and the adhesive layer contains an inorganic powder having better thermal conductivity than mica. 4. The mica substrate sheet according to claim 1, wherein the inorganic powder having a higher thermal conductivity than the mica contained in the thermal conductive layer has a particle size of 0.1 μm to 50 μm. 5. The mica layer is composed of mica aggregate, 5 to 50 parts by weight of synthetic fiber fibrid with respect to 100 parts by weight of the mica aggregate, and 5 to 5 parts by mass with respect to 100 parts by weight of the mica aggregate.
The particle size of the inorganic powder having good thermal conductivity, which is contained in 0 parts by weight of the mica layer, is 5 μm to 50 μm.
5. The mica base sheet according to any one of items 1 to 4. 6. The ratio of the adhesive layer to the whole of the mica layer, the filling backing material and the adhesive layer is 5 to 15% by weight, and the heat conduction to the whole of the mica layer, the filling backing material, the adhesive layer and the heat conducting layer. The mica substrate sheet according to any one of claims 1 to 5, wherein a ratio of the layer is 25 to 55% by weight, and the heat conductive layer contains 75 to 95% by weight of an inorganic powder having better heat conductivity than mica. body. 7. The heat conduction in the mica layer, the filling backing material, the adhesive layer and the heat conducting layer is 25 to 50% by weight of the mica layer, the filling backing material and the adhesive layer. The mica substrate sheet according to any one of claims 1 to 6, wherein a ratio of the layer is 20 to 50% by weight, and the heat conductive layer contains 65 to 85% by weight of an inorganic powder having better heat conductivity than mica. body. 8. An insulated coil having an insulating layer formed by a cured layer of the mica base sheet and the impregnated resin according to claim 6 on an insulating portion of the coil. 9. An impregnated resin layer containing an inorganic powder having a higher thermal conductivity than mica, and a particle diameter of the inorganic powder of 0.1%.
The insulated coil according to claim 8, wherein the thickness is 1 to 15 m. 10. An insulated coil in which an insulating layer is formed on the insulating portion of the coil by the mica base sheet according to claim 7 and the thermosetting layer containing the adhesive layer and the heat conductive layer.