WO2018179439A1

WO2018179439A1 - Coil for rotary electric device, method for producing coil for rotary electric device, mica tape, cured product of mica tape, and insulating article

Info

Publication number: WO2018179439A1
Application number: PCT/JP2017/013847
Authority: WO
Inventors: 士輝宋; 敬二福島; 竹澤　由高
Original assignee: 日立化成株式会社
Priority date: 2017-03-31
Filing date: 2017-03-31
Publication date: 2018-10-04

Abstract

Disclosed is a coil for a rotary electric device, the coil comprising: a coil conductor; and an insulating layer arranged on the outer circumference of the coil conductor. The insulating layer includes a mica tape. The mica tape includes: a mica layer including mica; and a backing layer including a backing material and an inorganic filler. The average thickness of the backing layer is at least 0.6 times the average thickness of the mica layer.

Description

Coil for rotating electrical machine, method for manufacturing coil for rotating electrical machine, mica tape, cured product and insulator of mica tape

The present invention relates to a coil for a rotating electrical machine, a method for manufacturing a coil for a rotating electrical machine, mica tape, a cured product of an mica tape, and an insulator.

As a material for forming an insulating layer for insulating a member such as a coil (insulator) from the external environment, an insulating material using mica called a mica tape is known. A mica tape generally has a backing layer containing a backing material and a mica layer containing mica, and an insulating layer is formed by curing a resin impregnated in the mica tape.

On the other hand, in the field of generators and the like that employ an indirect cooling method in which hydrogen gas or air is cooled outside the coil, it is desired that the insulating layer provided on the outside of the coil be highly thermally conductive. As a technique for increasing the thermal conductivity of the insulating layer, a technique in which an inorganic filler having a high thermal conductivity is contained in the mica tape can be mentioned.

For example, Patent Document 1 discloses a mica tape in which alumina having a high thermal conductivity is filled as an inorganic filler in a mica layer. By using this mica tape, 0.32 W / (m · K) is disclosed. An insulating layer having a thermal conductivity of ˜0.36 W / (m · K) is obtained.

Patent Document 2 discloses a sheet-like laminate in which a thermal conductive layer containing an inorganic filler having a high thermal conductivity is further disposed on one surface of a normal mica tape, and 0.35 W / It is said that an insulating layer having a thermal conductivity of (m · K) to 0.48 W / (m · K) can be obtained.

Patent Document 3 discloses a method in which HTC (high thermal conductivity) particles are infiltrated into a backing layer of a mica tape, and the composite tape is impregnated into the composite tape through the backing layer.

In Patent Document 4, a backing layer containing a filler having a high thermal conductivity formed on a mica layer is coated with a flat layer containing specific flat inorganic particles during the manufacture of a stator coil ( In particular, there is disclosed a method for forming an insulating covering having a high thermal conductivity without causing the filler previously carried during the heating press) to flow outside.

Japanese Patent Laid-Open No. 2005-199562 JP 2002-93257 A Special table 2009-532242 International Publication No. 2014/109167

Inclusion of an inorganic filler in the mica tape is effective as a technique for improving the thermal conductivity of the insulating layer. However, when the mica tape containing the inorganic filler is impregnated with the resin varnish, the inorganic filler is mixed into the resin varnish to deteriorate the quality of the resin varnish. The inorganic filler flows out of the mica tape into the resin varnish and remains in the insulating layer. There is a possibility that problems such as a decrease in the amount of the inorganic filler may occur.
Therefore, there is a limit to the amount of inorganic filler that the mica tape can contain. For this reason, development of the technique which makes an mica tape contain an inorganic filler effectively and improves the thermal conductivity of an insulating layer is awaited.

In view of the above circumstances, an object of the present invention is to provide a coil for a rotating electrical machine having an insulating layer with excellent thermal conductivity and a method for manufacturing the same. Another object of the present invention is to provide a mica tape capable of forming an insulating layer having excellent thermal conductivity, a cured product of the mica tape, and an insulator using the same.

Specific means for achieving the above object are as follows.
<1> a coil conductor and an insulating layer disposed on an outer periphery of the coil conductor, wherein the insulating layer includes a mica tape, and the mica tape includes a mica layer including mica, a backing material, and an inorganic filler. A coil for a rotating electrical machine, wherein the average thickness of the backing layer is not less than 0.6 times the average thickness of the mica layer.
<2> The rotating electrical machine coil according to <1>, wherein an average thickness of the backing layer in the mica tape is 1.5 times or less of an average thickness of the mica layer.
<3> The coil for a rotating electrical machine according to <1> or <2>, wherein the mass of the inorganic filler in the mica tape is 0.05 to 2.25 times the mass of the mica.
<4> The coil for a rotating electrical machine according to any one of <1> to <3>, wherein the inorganic filler in the mica tape has a volume average particle diameter of 1 μm to 40 μm.
<5> Any one of <1> to <4>, including the step of winding the mica tape around the outer periphery of the coil conductor and the step of forming an insulating layer from the mica tape wound around the outer periphery of the coil conductor A method for manufacturing a coil for a rotating electrical machine according to claim 1.
<6> The mica tape includes a resin component, and the content of the resin component is 5% by mass to 15% by mass of the total mass of the backing layer and the mica layer. A method of manufacturing a coil for a rotating electrical machine.

<7> A mica layer having a mica layer containing mica and a backing layer containing a backing material and an inorganic filler, wherein the average thickness of the backing layer is 0.6 times or more of the average thickness of the mica layer. tape.
<8> The mica tape according to <7>, wherein an average thickness of the backing layer is 1.5 times or less of an average thickness of the mica layer.
<9> The mica tape according to <7> or <8>, wherein the mass of the inorganic filler is 0.05 to 2.25 times the mass of the mica.
<10> The mica tape according to any one of <7> to <9>, wherein the inorganic filler has a volume average particle diameter of 1 μm to 40 μm.
<11> The resin component according to any one of <7> to <10>, including a resin component, wherein the content of the resin component is 5% by mass to 15% by mass of the total mass of the backing layer and the mica layer. Mica tape.
<12> A cured product of the mica tape according to <11>, obtained by curing the resin component.
<13> An insulator having an insulator and an insulating layer that is a cured product of the mica tape according to <12> disposed on at least a part of the surface of the insulator.

According to the present invention, a coil for a rotating electrical machine having an insulating layer excellent in thermal conductivity and a method for manufacturing the same are provided. Moreover, according to this invention, the mica tape which can form the insulating layer excellent in heat conductivity, the hardened | cured material of a mica tape, and an insulator using the same are provided.

It is a schematic sectional drawing which shows the structure of the mica tape of this embodiment. It is a schematic sectional drawing which shows the structure of the mica tape which does not satisfy | fill the conditions of this embodiment.

Hereinafter, embodiments for carrying out the present invention will be described in detail. However, the present invention is not limited to the following embodiments. In the following embodiments, the components (including element steps and the like) are not essential unless otherwise specified. The same applies to numerical values and ranges thereof, and the present invention is not limited thereto.

In this specification, the term “process” includes a process that is independent of other processes and includes the process if the purpose of the process is achieved even if it cannot be clearly distinguished from the other processes. It is.
In the present specification, numerical values indicated by using “to” include numerical values described before and after “to” as the minimum value and the maximum value, respectively.
In the numerical ranges described stepwise in this specification, the upper limit value or the lower limit value described in one numerical range may be replaced with the upper limit value or the lower limit value of another numerical range. Good. Further, in the numerical ranges described in this specification, the upper limit value or the lower limit value of the numerical range may be replaced with the values shown in the examples.
In the present specification, the content rate or content of each component in the composition is such that when there are a plurality of substances corresponding to each component in the composition, the plurality of kinds present in the composition unless otherwise specified. It means the total content or content of substances.
In the present specification, the particle diameter of each component in the composition is a mixture of the plurality of types of particles present in the composition unless there is a specific indication when there are a plurality of types of particles corresponding to each component in the composition. Means the value of.
In this specification, the term “layer” refers to the case where the layer is formed only in a part of the region in addition to the case where the layer is formed over the entire region. Is also included.
In this specification, the term “lamination” indicates that layers are stacked, and two or more layers may be combined, or two or more layers may be detachable.

<Coils for rotating electrical machines>
The coil for a rotating electrical machine of the present embodiment includes a coil conductor and an insulating layer disposed on an outer periphery of the coil conductor, the insulating layer includes a mica tape, and the mica tape includes a mica layer including mica. And a backing layer containing a backing material and an inorganic filler (however, mica is not included in the inorganic filler), and the average thickness of the backing layer is 0.6 of the average thickness of the mica layer It is more than double.

Details and preferred aspects of the mica tape used for forming the insulating layer of the coil of the present embodiment are the same as those of the mica tape of the present embodiment described later. Further, the material, shape, size, and the like of the coil conductor used in the coil of the present embodiment are not particularly limited, and can be selected according to the use of the coil.

<Manufacturing method of coil for rotating electrical machine>
The manufacturing method of the coil for rotary electric machines of this embodiment has the process of winding a mica tape around the outer periphery of a coil conductor, and the process of forming an insulating layer from the said mica tape wound around the outer periphery of the said coil conductor.

The method of winding the mica tape around the outer periphery of the coil conductor is not particularly limited, and a commonly performed method can be adopted.

The method for forming the insulating layer from the mica tape wound around the outer periphery of the coil conductor is not particularly limited. For example, after a mica tape is wound around a coil conductor, the mica tape is heated while being pressed (heat press), and the resin component contained in the mica tape is caused to flow out of the mica tape in advance to fill the space between the overlapping mica tapes. The resin component is then formed by a method of curing this to form an insulating layer (in the case of prepreg mica tape), and after winding the mica tape around the coil conductor, a vacuum pressure impregnation method (Vacuum Pressure Impression, VPI). Examples include a method of impregnating mica tape and curing it to form an insulating layer (in the case of dry mica tape).

<Mica tape>
The mica tape of the present embodiment has a mica layer containing mica and a backing layer containing a backing material and an inorganic filler, and the average thickness of the backing layer is 0.6 times the average thickness of the mica layer. That's it.

According to the study by the present inventors, an insulating layer formed from a mica tape in which the average thickness of the backing layer and the average thickness of the mica layer satisfy the above conditions has a high thermal conductivity (for example, 0.4 W / (m · K). ))). That is, an insulating layer having excellent thermal conductivity can be formed by selecting the average thickness of the backing layer and the average thickness of the mica layer so that the above conditions are satisfied.

From the viewpoint of obtaining higher thermal conductivity, the average thickness of the backing layer is preferably 0.8 times or more, more preferably 1.2 times or more the average thickness of the mica layer.
On the other hand, from the viewpoint of ease of winding the mica tape and insulating properties, the average thickness of the backing layer is preferably 1.5 times or less, more preferably 1.2 times or less than the average thickness of the mica layer. preferable.

The average thickness of the mica layer is not particularly limited. From the viewpoint of ease of winding the mica tape, the average thickness of the mica layer is preferably 180 μm or less, and more preferably 170 μm or less. From the viewpoint of electrical insulation, the average thickness of the mica layer is preferably 80 μm or more, and more preferably 90 μm or more.

The average thickness of the backing layer is not particularly limited. From the viewpoint of ease of winding the mica tape, the average thickness of the backing layer is preferably 100 μm or less, and more preferably 70 μm or less. From the viewpoint of the strength of the mica tape, the average thickness of the backing layer is preferably 10 μm or more, and more preferably 20 μm or more.

In this embodiment, the average thickness of the mica layer and the average thickness of the backing layer can be determined by the following method, for example.

Measure the average thickness of mica tape by measuring the thickness at 10 points using a micrometer (Mitutoyo Corporation, “MDC-SB”). Also, separating the backing layer and the mica layer of the mica sheet, obtaining the average thickness of the backing layer in the same manner as the average thickness of the mica sheet, and further subtracting the average thickness of the backing layer from the average thickness of the mica sheet To obtain the average thickness of the mica layer.

Alternatively, the thickness of the mica layer and the backing layer in the cross section of the mica tape or insulating layer is observed at three points using an optical microscope and a micrometer (for example, Olympus Corporation, “BX51” and “OB-M”). Obtained as the arithmetic average value of the measured values.

FIG. 1 is a schematic cross-sectional view showing an example of the structure of the mica tape of this embodiment. As shown in FIG. 1, the mica tape may have a mica layer 2 containing mica 6 and a backing layer 1 containing a backing material 3 and an inorganic filler 5. Further, the mica layer 2 and the backing layer 1 may each contain a resin component 4. In FIG. 1, the resin component 4 is included only in the backing layer 1, but may be included in the mica layer 2. When the mica layer 2 (or the backing layer 1) includes the resin component 4, the resin component 4 may be included in the entire mica layer 2 (or the backing layer 1) or may be partially included. FIG. 2 is a schematic sectional view showing an example of the structure of a mica tape that does not satisfy the condition that the average thickness of the backing layer is 0.6 times or more the average thickness of the mica layer.

The mica tape of this embodiment is a mica tape (prepreg mica tape) used in a method for forming an insulating layer by curing a resin component contained in a mica tape in advance after the mica tape is wound around an object to be insulated. Alternatively, it may be a mica tape (dry mica tape) used in a method of forming an insulating layer by curing a resin component impregnated after being wound around an insulator.

(Mica)
The kind of mica is not particularly limited. Examples include unfired hard mica, fired hard mica, unfired soft mica, fired soft mica, synthetic mica, and flake mica. Among these, unfired hard mica that does not go through the firing step is preferable from the viewpoint of price and availability.

The particle size of mica is not particularly limited. For example, from the viewpoint of insulation, when sieving using a JIS standard sieve, the proportion of mica pieces having a particle diameter of 2.8 mm or more is preferably less than 45% by mass of the whole mica pieces, It is more preferably 30% by mass or less, and further preferably 20% by mass or less, based on the entire mica piece.

From the viewpoint of securing sufficient dielectric breakdown electric field strength, the proportion of mica pieces having a particle diameter of 0.5 mm or more when sieved using a JIS standard sieve is 40% by mass or more of the entire mica pieces. Is preferable, and it is more preferable that it is 60 mass% or more.

The JIS standard sieve conforms to JIS-Z-8801-1: 2006 and conforms to ISO3310-1: 2000. When ISO 3310-1: 2000 is used, it is preferable to apply a sieve having a square shape as in JIS-Z-8801-1: 2006.

The ratio of mica pieces having a particle diameter of 2.8 mm or more when sieving using a JIS standard sieve in mica contained in the mica tape, and the ratio of mica pieces having a particle diameter of 0.5 mm or more are, for example, It can be confirmed as follows.

Insert a razor into the interface between the backing layer and the mica layer of the mica tape, and peel off the mica layer from the backing layer. 1 g of the peeled mica layer is dispersed in 100 g of methyl ethyl ketone, shaken for 10 minutes, and then centrifuged at 8000 rotations / minute (rpm) for 5 minutes. 100 g of methyl ethyl ketone is added to the solid content remaining after removing the supernatant, shaken for 10 minutes, and then centrifuged at 8000 rpm for 5 minutes. Further, 100 g of methyl ethyl ketone is added to the remaining solid after removing the supernatant, and the mixture is shaken for 10 minutes and then centrifuged at 8000 rpm for 5 minutes. The supernatant is removed, 100 g of methyl ethyl ketone is added to 1 g of the remaining solid, and the mixture is dispersed for 30 minutes with a mix rotor and shaken for another 10 minutes. Then, while shaking the container, JIS standard sieves (JIS-Z-8801-1: 2006, ISO3310-1: 2000, Tokyo Screen Co., Ltd., test sieve) ).

The method of sieving is not particularly limited. For example, while vibrating a JIS standard sieve having a predetermined opening provided in a low-tap type sieve vibrator for 10 minutes (hammer stroke: 120 times / minute) This can be done by passing through a sieve.

As a result of sieving, a mica piece that has not passed through a sieve having an opening of 2.8 mm (or 0.5 mm) is defined as a “mica piece having a particle diameter of 2.8 mm (or 0.5 mm) or more”. The ratio (mass%) of “mica pieces with a particle diameter of 2.8 mm (or 0.5 mm) or more” in the total amount of mica pieces before being divided is “particle diameter when sieving using a JIS standard sieve. Is the ratio of mica pieces with 2.8 mm (or 0.5 mm) or more.

Mica may be used alone or in combination of two or more. When two or more mica are used in combination, for example, when two or more mica having the same component and different particle sizes are used, when two or more mica having the same particle size and different components are used, and the average particle size and component The case where 2 or more types of mica having different types is used is mentioned.

The amount of mica in the mica layer is not particularly limited. For example, a range of 80 g / m ² to 230 g / m ² is preferable, and a range of 100 g / m ² to 200 g / m ² is more preferable. If the amount of mica in the mica layer is 80 g / m ² or more, a decrease in insulation tends to be suppressed. If the amount of mica in the mica layer is 230 g / m ² or less, the mica tape can be thinned and the decrease in thermal conductivity tends to be suppressed.

(Lining material)
The type of the backing material is not particularly limited. For example, a glass cloth is mentioned. By using glass cloth as the backing material, the inorganic filler is taken in between the fibers constituting the glass cloth, and the falling of the inorganic filler tends to be suppressed. Further, the resin component penetrated between the fibers tends to be well integrated with the adjacent mica layer, and the thermal conductivity tends to be improved.

When a glass cloth is used as the backing material, a part of the fiber may be an organic material. The fiber comprised in particular with an organic material is not restrict | limited, Fibers, such as an aramid, polyamide, a polyimide, polyester, are mentioned. When a part of the glass cloth is a fiber composed of an organic material, the warp, the weft, or both may be a fiber composed of an organic material.
The average thickness of the backing material is not particularly limited. For example, the thickness is preferably 10 μm to 100 μm, more preferably 20 μm to 70 μm. If the average thickness of the backing material is 10 μm or more, it is suppressed that the backing layer is too thin following the thickness of the backing material when the mica tape is pressed, and a decrease in thermal conductivity is suppressed. There is a tendency. If the average thickness of the backing material is 100 μm or less, the mica tape can be prevented from becoming thick, and the occurrence of breakage, cracks, etc. of the mica tape during the process of winding the mica tape around the insulator is likely to be suppressed. .

The average thickness of the backing material is preferably 0.6 to 1.5 times the thickness of the mica layer in the mica tape.

In this embodiment, the average thickness of the backing material is the arithmetic average value of the measured values obtained by measuring the thickness of the backing material at a total of 10 locations using a micrometer (MDC-SB, Mitutoyo Corporation). . The average thickness of the backing material (backing layer) in the mica tape is a value measured by the method described later.

The backing material may be surface-treated if necessary. Examples of the surface treatment method for the backing material include treatment with a silane coupling agent.

(Inorganic filler)
The kind of inorganic filler is not particularly limited. Examples include silica, boron nitride, and alumina. From the viewpoint of thermal conductivity, boron nitride is preferable. Boron nitride exhibits higher thermal conductivity than other inorganic fillers (eg, alumina). Therefore, when the backing layer contains boron nitride, the thermal conductivity of the insulating layer formed from the mica tape tends to be improved. Boron nitride has a Mohs hardness of 2 and is a soft filler as compared with alumina (Mohs hardness 9), so that flexibility can be imparted to the tape.

The type of boron nitride is not particularly limited, and examples include hexagonal boron nitride (h-BN), cubic boron nitride (c-BN), and wurtzite boron nitride. Among these, hexagonal boron nitride (h-BN) is preferable. The boron nitride may be primary particles of boron nitride formed in a scale shape or secondary particles formed by agglomeration of primary particles.

The average particle diameter of the inorganic filler is not particularly limited. For example, it is preferably 1 μm to 40 μm, more preferably 5 μm to 20 μm, and even more preferably 5 μm to 10 μm.
When the average particle size of the inorganic filler is 1 μm or more, the thermal conductivity and the dielectric strength voltage tend to be further improved. In addition, the outflow of fine inorganic filler particles in the resin impregnation step of impregnating the mica tape with the resin component. Tend to be suppressed. When the average particle size of the inorganic filler is 40 μm or less, the anisotropy of the thermal conductivity due to the anisotropy of the particle shape tends to be suppressed, and the protrusion of the inorganic filler particles from the tape surface is suppressed. In the resin impregnation step, the outflow of the inorganic filler tends to be suppressed.

The average particle size of the inorganic filler can be measured by using, for example, a laser diffraction / scattering particle size distribution measuring apparatus (Nikkiso Co., Ltd., “Microtrack MT3000II”). Specifically, an inorganic filler is introduced into pure water and then dispersed with an ultrasonic disperser. By measuring the particle size distribution of the dispersion, the particle size distribution of the inorganic filler is measured. Based on this particle size distribution, the particle size (D50) corresponding to 50% volume accumulation from the small diameter side is determined as the average particle size.

The inorganic filler may be used alone or in combination of two or more. As a case where two or more inorganic fillers are used in combination, for example, when two or more inorganic fillers having the same component and different average particle sizes are used, two or more inorganic fillers having the same average particle size and different components are used, and A case where two or more inorganic fillers having different average particle diameters and types are used.

If necessary, the inorganic filler may be surface-treated by a coupling agent, heat treatment or light treatment.
For example, in the case of heat treatment, by heating the inorganic filler at a suitable high temperature (eg, 250 ° C. to 800 ° C.) for a predetermined time (eg, 1 hour to 3 hours), the surface state of the inorganic filler is modified, When the filler is mixed with the resin component, the affinity is improved, and the viscosity of the composition containing the inorganic filler and the resin component is lowered and tends to be easily applied. Further, the coated surface of the composition has few smears and irregularities and tends to improve smoothness.

The mass ratio between the inorganic filler and the mica in the mica tape is not particularly limited. For example, the mass of the inorganic filler contained in the mica tape is preferably 0.05 to 2.25 times, more preferably 0.05 to 1.50 times, and preferably 0.1 to The ratio is more preferably 1.0 times, and further preferably 0.1 to 0.6 times. If the mass of the inorganic filler is 0.05 times or more of the mass of mica, sufficient thermal conductivity tends to be obtained, and if it is 2.25 times or less, sufficient insulation tends to be obtained.

(Resin component)
The mica tape may contain a resin component. The kind of resin used as the resin component is not particularly limited. From the viewpoint of curing the mica tape to form the insulating layer, a curable resin is preferable, and a thermosetting resin is more preferable. Examples of the curable resin include an epoxy resin, a phenol resin, an unsaturated polyester resin, and a silicone resin. From the viewpoint of adhesion between the mica layer and the backing layer and electrical insulation, an epoxy resin is preferable.

Epoxy resins in the case of using an epoxy resin as a resin component include bisphenol A type epoxy resin, bisphenol F type epoxy resin, phenol novolac type epoxy resin, cresol novolak type epoxy resin, naphthalene type epoxy resin, cycloaliphatic epoxy resin, etc. Is mentioned. Among these, from the viewpoint of heat resistance, phenol novolac type epoxy resins, bisphenol A type epoxy resins and bisphenol F type epoxy resins are preferable.

The epoxy equivalent of the epoxy resin is not particularly limited. For example, it is preferably 130 g / eq to 500 g / eq, more preferably 135 g / eq to 400 g / eq, and even more preferably 140 g / eq to 300 g / eq. The epoxy equivalent is measured by dissolving a precisely weighed epoxy resin in a solvent such as methyl ethyl ketone, adding acetic acid and a tetraethylammonium bromide acetic acid solution, and then performing potentiometric titration with a perchloric acid acetic acid standard solution. An indicator may be used for potentiometric titration.

The number average molecular weight of the resin used as the resin component is not particularly limited. For example, from the viewpoint of fluidity, it is preferably 100 to 100,000, more preferably 200 to 50,000, and still more preferably 300 to 10,000. The number average molecular weight is a value measured by gel permeation chromatography (GPC). The number average molecular weight of the resin is a value measured under the following conditions using a gel permeation chromatography method (GPC) according to a conventional method.

〔Measurement condition〕
Pump: L-6000 (Hitachi, Ltd.)
Column: TSKgel (registered trademark) G4000HHR + G3000HHR + G2000HXL (Tosoh Corporation)
Column temperature: 40 ° C
Elution solvent: Tetrahydrofuran (without chromatography stabilizer, Wako Pure Chemical Industries, Ltd.)
Sample concentration: 5 g / L (tetrahydrofuran soluble component)
Injection volume: 100 μL
Flow rate: 1.0 mL / min Detector: Differential refractometer (RI-8020, Tosoh Corporation)
Molecular weight calibration reference material: Standard polystyrene Data processor: GPC-8020 (Tosoh Corporation)

When the mica tape contains a curable resin as a resin component, a curing agent may be included as a resin component. The curing agent is not particularly limited and can be appropriately selected depending on the type of the curable resin. A hardening | curing agent may be used individually by 1 type, or may use 2 or more types together.
When the curable resin is an epoxy resin, the curing agent can be appropriately selected from curing agents usually used as a curing agent for epoxy resins. Specific examples include amine curing agents such as dicyandiamide and aromatic diamine; phenol resin curing agents such as phenol novolac and cresol novolac; acid anhydride curing agents such as alicyclic acid anhydrides and the like. When the curable resin is an epoxy resin, the ratio of the curing agent to the epoxy resin should be 0.8 to 1.2 in terms of equivalent ratio (curing agent / epoxy resin) from the viewpoint of curability and electrical characteristics of the cured product To preferred.

(Curing catalyst)
When the mica tape includes a curable resin as a resin component, a curing catalyst may be included for the purpose of accelerating the curing reaction of the curable resin. The curing catalyst is not particularly limited, and can be selected according to the type of the curable resin and the curing agent used as necessary. Specific examples of the curing catalyst include tertiary amine compounds such as trimethylamine, imidazole compounds such as 2-methylimidazole and 2-methyl-4-ethylimidazole, organometallic salts such as tin, zinc and cobalt, boron trifluoride. Examples include amine complexes of Lewis acids such as monoethylamine, and organic phosphorus compounds such as organic phosphine compounds. A hardening accelerator may be used individually by 1 type, or may use 2 or more types together.
When the mica tape contains a curing catalyst, the content is not particularly limited. For example, when an epoxy resin is used as the resin component, the content of the curing catalyst is generally in the range of 0.01% by mass to 5% by mass with respect to the total amount of the epoxy resin and the curing agent included as necessary. is there.

(Other ingredients)
The mica tape may contain other components other than the components described above as necessary. Examples of other components include coupling agents, antioxidants, anti-aging agents, stabilizers, flame retardants, and thickeners.

<Overall configuration of mica tape>
The mica tape of this embodiment has a mica layer containing mica and a backing layer containing a backing material and an inorganic filler, and may have other layers as necessary. Examples of the other layer include a protective layer (protective film) provided on the outermost surface of the mica tape.

The average thickness of the mica tape (the total thickness of the mica layer and the backing layer) is not particularly limited. For example, the average thickness of the mica tape may be 400 μm or less, preferably 350 μm or less, and more preferably 300 μm or less.

When the mica tape is used as a prepreg mica tape, the average thickness of the mica tape is preferably 300 μm or less and more preferably 290 μm or less from the viewpoint of easy winding of the mica tape. From the viewpoint of electrical insulation, the average thickness of the mica tape is preferably 120 μm or more, more preferably 150 μm or more, and further preferably 160 μm or more.

When the mica tape is used as a dry mica tape, the average thickness of the mica tape is preferably 220 μm or less and more preferably 190 μm or less from the viewpoint of ease of winding the mica tape. From the viewpoint of electrical insulation, the average thickness of the mica tape is preferably 120 μm or more, more preferably 150 μm or more, and further preferably 160 μm or more.

In this embodiment, the average thickness of the mica tape (the total thickness of the mica layer and the backing layer) was measured at a total of 10 locations using a micrometer (MDC-SB, Mitutoyo Corporation). The arithmetic average value of the measured values obtained is used.

The content of the inorganic filler in the nonvolatile content excluding mica and the backing material of the mica tape is not particularly limited. For example, it is preferably 20% by volume to 50% by volume and more preferably 25% by volume to 35% by volume of the total volume of the non-volatile content excluding mica and the backing material. When the content of the inorganic filler is 20% by volume or more of the total volume of nonvolatile components excluding mica and the backing material, the thermal conductivity of the insulating layer formed from the mica tape tends to be further improved. When the content of the inorganic filler is 50% by volume or less of the total volume of non-volatile components excluding mica and the backing material, filling of the inorganic filler into the resin component tends to be facilitated.

The content of non-volatile components excluding mica and the backing material in the total mass of the mica layer and the backing layer of the mica tape is not particularly limited. For example, it is preferably 5% by mass to 45% by mass of the total mass of the mica layer and the backing layer, more preferably 10% by mass to 30% by mass, and further preferably 15% by mass to 20% by mass. preferable. When the content of nonvolatile components excluding mica and the backing material is 5% by mass or more of the total mass of the mica layer and the backing layer, the thermal conductivity tends to be more effectively improved. When the non-volatile content excluding mica and the backing material is 45% by mass or less of the total mass of the mica layer and the backing layer, an increase in the thickness of the mica tape tends to be suppressed. Further, varnish impregnation tends to proceed during the production of mica tape.

The content of the resin component in the nonvolatile content excluding mica and the backing material of the mica tape is not particularly limited. For example, it is preferably 35% by mass to 70% by mass, more preferably 50% by mass to 65% by mass, and more preferably 55% by mass to 60% by mass with respect to the total mass of the nonvolatile content excluding mica and the backing material. More preferably. When the content of the resin component is 35% by mass or more of the total mass of nonvolatile components excluding mica and the backing material, the adhesion between the backing layer and the mica layer tends to be improved. When the content of the resin component is 70% by mass or less of the total nonvolatile content excluding mica and the backing material, the thermal conductivity tends to be improved.

The content of the resin component in the mica tape is not particularly limited and can be selected according to the use of the mica tape. For example, the content of the resin component may be 40% by mass or less of the total mass of the mica layer and the backing layer, and is preferably 5% by mass to 33% by mass.

When the mica tape is used as a prepreg mica tape, the content of the resin component is preferably 25% by mass to 33% by mass of the total mass of the mica layer and the backing layer, for example, 25% by mass to 30% by mass. It is more preferable that When the content of the resin component is 25% by mass or more of the total mass of the mica layer and the backing layer, the mica from the mica tape and, if necessary, the falling off (powder off) of the inorganic filler are suppressed, and the insulator As a result of the occurrence of cracks, cuts, wrinkles, and the like of the mica tape when the mica tape is wound around, the insulation reliability and the thermal conductivity tend to be suppressed. On the other hand, when the content of the resin component is 33% by mass or less of the total mass of the mica layer and the backing layer, an increase in the thickness of the mica tape is suppressed and good winding properties tend to be maintained. Furthermore, the resin component tends to be prevented from flowing out beyond the volume necessary to fill the gap between the overlapping mica tapes with the mica tape wound around the insulator. As a result, generation of voids is reduced, and a decrease in insulation reliability tends to be suppressed.

When the mica tape is used as a dry mica tape, the content of the resin component in the mica tape is preferably 5% by mass to 15% by mass of the total mass of the mica layer and the backing layer, for example, 5% by mass. More preferably, it is ˜12% by mass, and further preferably 8% by mass to 10% by mass. When the content of the resin component is 5% by mass or more of the total mass of the mica layer and the backing layer, the adhesion between the backing layer and the mica layer tends to be sufficiently secured. On the other hand, when the content of the resin component is 15% by mass or less of the total mass of the mica layer and the backing layer, high thermal conductivity tends to be achieved.

In this embodiment, the content rate of the resin component in the mica tape is calculated by the following method, for example.
The mica tape cut to a size of 30 mm in width and 50 mm in length is heated in an electric furnace at 600 ° C. for 2 hours, and the mass reduction rate (%) before and after heating is obtained by the following formula. The above process is performed three times, and an arithmetic average value of the obtained values is obtained.
Content of resin component = {(mass before heating−mass after heating) / mass before heating} × 100

When the mica tape is used as a dry mica tape, the content of the resin component in the mica layer is preferably 15% by mass or less of the total mass of the mica layer, and more preferably 10% by mass or less. More preferably, it is 5 mass% or less.

The mica layer preferably contains substantially no inorganic filler other than mica. Specifically, the content of the inorganic filler other than mica in the mica layer is preferably 3% by mass or less, more preferably 2% by mass or less, and more preferably 1% by mass or less of the total mass of the mica layer. More preferably, it is particularly preferably 0% by mass.

From the viewpoint of suppressing a decrease in thermal conductivity, it is preferable that the mica layer does not substantially contain fibrites. Specifically, the content of fibrils in the mica layer is preferably 1% by mass or less of the total mass of the mica layer, more preferably 0.5% by mass or less, and 0.1% by mass. The following is more preferable, and 0% by mass is particularly preferable. In this specification, the fibrit is a fibrous substance mixed so that the mica layer can stand on its own, and examples thereof include organic fibers such as polyamide and polyimide, and inorganic fibers such as glass fibers.

The mica tape of this embodiment can be used for forming an insulating layer of an insulator such as a coil.

<Mica tape manufacturing method>
The mica tape of this embodiment may be manufactured through any process, and conventionally known manufacturing methods can be applied.

As an example of a method for producing a mica tape, a step of preparing a laminate by placing a backing material on mica paper, a composition (varnish) containing an inorganic filler and a resin component, the composition of the laminate And a step of applying to the backing material side.

The details and preferred embodiments of the mica, backing material, inorganic filler and resin component used in the above method, and the produced mica tape are as described above. The mica paper is a sheet-like object formed by collecting mica pieces.

If necessary, the composition may contain a solvent. By including the solvent, the viscosity of the composition is lowered, and the inorganic filler tends to be easily mixed. The type of the solvent is not particularly limited, and can be selected from commonly used organic solvents. Specific examples include methyl ethyl ketone, toluene, methanol, cyclohexanone and the like. A solvent may be used individually by 1 type, or may use 2 or more types together.

The content of the inorganic filler in the composition is not particularly limited. For example, the content is preferably 20% by volume to 50% by volume, and more preferably 25% by volume to 35% by volume, based on the entire nonvolatile content (components excluding the solvent) of the composition. When the content of the inorganic filler is 20% by volume or more of the entire nonvolatile content of the composition, the thermal conductivity of the insulating layer formed using mica tape tends to be further improved. When the content of the inorganic filler is 50% by volume or less of the entire nonvolatile content of the composition, the mixing property of the inorganic filler and the resin component tends to be improved.

Application of the composition is preferably carried out so that the composition applied to the backing material oozes out to the other side of the backing material and penetrates all or part of the mica paper. In this case, even if it is not a fibrotic mixed paper, the mica paper can easily become independent and is not easily collapsed. By using mica paper that does not contain fibrites, the thermal conductivity tends to be improved.

<Hardened mica tape>
The cured product of the mica tape of this embodiment is obtained by curing the mica tape described above. More specifically, it is obtained by curing a resin component contained in a mica tape. The curing method is not particularly limited, and can be selected from ordinary methods. The resin component may be contained in advance in the mica tape before being wound around the insulator, or may be impregnated after the mica tape is wound around the insulator.

<Insulator>
The insulator of this embodiment includes an insulator and an insulating layer that is a cured product of the mica tape of this embodiment that is disposed on at least a part of the surface of the insulator. The method for forming the insulating layer using the mica tape of the present embodiment is not particularly limited, and conventionally known production methods can be applied. For example, after winding mica tape around an insulator, heat it while applying pressure to the mica tape (heat press), and let the resin component contained in the mica tape flow out of the mica tape in advance and overlap between the overlapping mica tapes. The resin component is formed by filling and curing this to form an insulating layer (in the case of prepreg mica tape), after winding mica tape around the insulator, and by vacuum pressure impregnation (Vacuum Pressure Impression, VPI). A method of impregnating a mica tape and curing the same to form an insulating layer (in the case of dry mica tape).

When the insulating layer is formed by the vacuum pressure impregnation method, the resin component impregnated into the mica tape is not particularly limited. For example, what contains epoxy resins, such as a bisphenol A type epoxy resin, and hardening | curing agents, such as an alicyclic acid anhydride, is mentioned. For the impregnation method of the resin component in the vacuum pressure impregnation method, the curing conditions after the impregnation, the ratio of the epoxy resin and the curing agent, etc., conventionally known methods, known conditions and the like can be referred to.

The insulator to be applied to the insulator according to the present embodiment is not particularly limited, and examples thereof include a coil, a bar-shaped copper, and a plate-shaped copper.

By using the mica tape of this embodiment, an insulating layer exhibiting high thermal conductivity can be formed. Therefore, when the insulator of this embodiment is a coil, when cooling the coil, a hydrogen cooling method or an air cooling method should be adopted even for a coil of a scale that conventionally employs a direct water cooling method. As a result, the coil structure can be simplified.

Hereinafter, the present invention will be specifically described by way of examples. However, the present invention is not limited to these examples.

<Example 1>
(1) Production of mica paper Unfired hard mica was dispersed in water to form mica particles, and the mica was made with a paper machine to produce mica paper having a mica amount of 120 g / m ² .

(2) Preparation of boron nitride-containing resin varnish Bisphenol A type epoxy resin (Mitsubishi Chemical Corporation, “Epicoat 828”) as a resin component, zinc (II) acetylacetonate (Pure Chemical Co., Ltd.) as a curing catalyst, solvent As a mixture, methyl ethyl ketone (Wako Pure Chemical Industries, Ltd.) was mixed. Thereafter, boron nitride (volume average particle diameter of 5 μm, Denki Kagaku Kogyo Co., Ltd.) was added and further mixed to prepare a boron nitride-containing resin varnish.
The mass ratio of the epoxy resin and the curing catalyst (epoxy resin: curing catalyst) was 97: 3.
In addition, the content rate of the boron nitride with respect to the total non volatile matter (except a solvent, ie, binder material) of a boron nitride containing resin varnish was 70 mass%.

(3) Production of Mica Sheet A glass cloth (average thickness: 45 μm) was placed on mica paper, and a boron nitride-containing resin varnish was applied on the glass cloth with a roll coater. The application was performed so that the resin component penetrated into the mica paper under the glass cloth. Thereafter, it was dried to prepare a mica sheet.

The average thickness of the obtained mica sheet was determined by measuring the thickness at 10 points using a micrometer (Mitutoyo Corporation, “MDC-SB”) and calculating the arithmetic average value. In addition, the backing layer and the mica layer of the obtained mica sheet are separated, and the average thickness of the backing layer is obtained in the same manner as the average thickness of the mica sheet. Further, the average thickness of the backing layer is determined from the average thickness of the mica sheet. The average thickness of the mica layer was determined by reducing. The results are shown in Table 1.

(4) Preparation of laminated cured product of mica sheet The mica sheet obtained by the above-described method was layered on 25 layers and immersed in an impregnating varnish, and the impregnating varnish was infiltrated into the mica sheet by a vacuum impregnation method. Thereafter, the resin component was cured by heat pressing at 130 ° C. for 2 hours and then at 190 ° C. for 2 hours to prepare a laminated cured product.
As the impregnating varnish, bisphenol A type epoxy resin (Mitsubishi Chemical Corporation, “Epicoat 828”) and a curing agent (Hitachi Chemical Co., Ltd., “HN-5500”, methylhexahydrophthalic anhydride) are used on a mass basis. What was mixed in 1 was used.

<Evaluation of thermal conductivity>
Using the thermal conductivity meter (Eihiro Seiki Co., Ltd., “HC-110”), the thermal conductivity (W / (m · K)) of the laminated cured product was obtained for the laminated cured product of the mica sheet obtained above. The thermal conductivity was evaluated according to the following criteria. The results are shown in Table 1.
A: Thermal conductivity is 0.40 W / (m · K) or more.
B: Thermal conductivity is less than 0.40 W / (m · K).

<Examples 2 to 7, Comparative Examples 1 to 5>
A mica sheet was produced in the same manner as in Example 1 except that the mica amount of mica paper used for the production of the mica sheet and the average thickness of the glass cloth were changed as shown in Table 1, and the mica sheet, the backing layer and the mica layer were produced. The average thickness of was measured in the same manner as in Example 1. The results are shown in Table 1. Further, a laminated cured product of mica sheets was produced in the same manner as in Example 1, and the thermal conductivity was evaluated. The results are shown in Table 1.

As shown in Table 1, the laminated cured product of the mica sheet in which the average thickness of the backing layer is 0.6 times or more of the average thickness of the mica layer, the average thickness of the backing layer is that of the average thickness of the mica layer. It was excellent in thermal conductivity as compared with the laminated cured product of mica sheet that was less than 0.6 times. From this, it was found that the mica tape of this embodiment can form an insulating layer having excellent thermal conductivity.

1 Backing layer 2 Mica layer 3 Backing material 4 Resin component 5 Inorganic filler 6 Mica

Claims

A coil conductor; and an insulating layer disposed on an outer periphery of the coil conductor, wherein the insulating layer includes a mica tape, and the mica tape includes a mica layer including mica, and a backing including a backing material and an inorganic filler. A coil for rotating electrical machines, wherein the average thickness of the backing layer is 0.6 times or more the average thickness of the mica layer.
The coil for rotating electrical machines according to claim 1, wherein an average thickness of the backing layer in the mica tape is 1.5 times or less of an average thickness of the mica layer.
The rotating electrical machine coil according to claim 1 or 2, wherein the mass of the inorganic filler in the mica tape is 0.05 to 2.25 times the mass of the mica.
The coil for a rotating electrical machine according to any one of claims 1 to 3, wherein a volume average particle diameter of the inorganic filler in the mica tape is 1 µm to 40 µm.
Winding the mica tape around the outer circumference of the coil conductor;
The method for manufacturing a coil for a rotating electrical machine according to any one of claims 1 to 4, further comprising: forming an insulating layer from the mica tape wound around the outer periphery of the coil conductor.
6. The rotating electrical machine according to claim 5, wherein the mica tape includes a resin component, and the content of the resin component is 5% by mass to 15% by mass of the total mass of the backing layer and the mica layer. Coil manufacturing method.
A mica tape having a mica layer containing mica and a backing layer containing a backing material and an inorganic filler, wherein the average thickness of the backing layer is 0.6 times or more of the average thickness of the mica layer.
The mica tape according to claim 7, wherein an average thickness of the backing layer is 1.5 times or less of an average thickness of the mica layer.
The mica tape according to claim 7 or 8, wherein the mass of the inorganic filler is 0.05 to 2.25 times the mass of the mica.
10. The mica tape according to any one of claims 7 to 9, wherein the inorganic filler has a volume average particle diameter of 1 μm to 40 μm.
The mica tape according to any one of claims 7 to 10, comprising a resin component, wherein a content of the resin component is 5% by mass to 15% by mass of a total mass of the backing layer and the mica layer. .
The cured product of mica tape according to claim 11, obtained by curing the resin component.
An insulator having an insulator and an insulating layer that is a cured product of the mica tape according to claim 12 disposed on at least a part of a surface of the insulator.