WO2019130588A1 - Prepreg mica tape, coil for rotary electrical machine, and production method therefor - Google Patents

Abstract

This prepreg mica tape comprises: a mica-containing layer containing a thermosetting resin, a curing agent, and mica; and a backing layer containing a thermosetting resin, a curing agent, and a backing material, which is provided on one of the sides of the mica-containing layer. The obverse face of the mica-containing layer and/or the obverse face of the backing layer is cured to a greater extent than the inner side, in the thickness direction, of the mica-containing layer and the backing layer.

Description

Prepreg mica tape, coil for rotating electrical machine and method of manufacturing the same

The present invention relates to a prepreg mica tape, a coil for a rotating electrical machine, and a method of manufacturing the same.

In order to ensure the insulation of the coil, an insulating layer is formed on at least a part of the outer periphery of the coil conductor. A prepreg (resin rich) mica tape or a dry mica tape is used to form the insulating layer.
The prepreg mica tape mainly comprises a backing material, mica paper, and a thermosetting resin composition previously impregnated with mica paper. On the other hand, the dry mica tape mainly includes a backing material, mica paper, and an adhesive layer that integrally bonds the backing material and the mica paper.

When forming an insulating layer using a prepreg mica tape, a prepreg mica tape is wound around a portion requiring insulation of a coil conductor, and is heated while being pressurized to cure a thermosetting resin composition which is impregnated in mica paper in advance. Thus, the insulating layer is formed.
For example, WO 2015/053374 discloses a prepreg mica tape using a thermosetting resin composition containing an epoxy resin and BF ₃ monoethylamine complex as a curing agent.

In an ordinary prepreg mica tape, when winding up the prepreg mica tape in a roll, a separator is inserted so that the tapes do not stick. As a material of the separator, polyethylene film, non-woven fabric, glass cloth or the like is used. In the case of a taping operation of winding a prepreg mica tape around a coil conductor to form a laminate of the prepreg mica tape, fragments of the separator may be mixed in the laminate, which may lead to a decrease in electrical insulation. In addition, when the separator is inserted, it is necessary to add an apparatus for removing the separator at the time of taping of the prepreg mica tape, which may make the taping operation complicated. Therefore, a method for winding a prepreg mica tape in a roll without using a separator is required.
Moreover, a thermosetting resin composition may adhere to the separator removed from the prepreg mica tape. Since the separator to which the thermosetting resin composition has adhered is inferior to recyclability, the method of suppressing adhesion of the thermosetting resin composition to a separator is calculated | required.

One embodiment of the present invention is made in view of the above-mentioned conventional circumstances, and it is possible to secure flexibility required at the time of winding, and a prepreg mica tape in which surface adhesiveness is suppressed and a rotating electrical machine using the same. Coil and method of manufacturing the same

The specific means for achieving the said subject are as follows.
<1> A mica-containing layer comprising a thermosetting resin, a curing agent and mica, a backing layer comprising a thermosetting resin, a curing agent and a backing material provided on one side of the mica-containing layer, Have
The prepreg mica tape in which at least one of the surface of the mica containing layer and the surface of the backing layer is cured more than the inner side in the thickness direction of the mica containing layer and the backing layer.
<2> A mica-containing layer comprising a thermosetting resin, a curing agent and mica, a backing layer comprising a thermosetting resin, a curing agent and a backing material provided on one side of the mica-containing layer, Have
A prepreg mica tape in which the degree of cure of the thermosetting resin on at least one of the surface of the mica-containing layer and the surface of the backing layer is 30% to 80%.
<3> A mica-containing layer containing an epoxy resin, a curing agent, and mica, and a backing layer containing an epoxy resin, a curing agent, and a backing material provided on one side of the mica-containing layer,
At least one of the surfaces of the mica-containing layer and the surface of the backing layer, the 1230 cm -1 ^~ 1250 cm peaks present in the range of ^-1 absorbance I _E and the epoxy resin derived from an epoxy group contained in the epoxy resin the ratio between the absorbance _{I P} of peaks present in the range of ^{1500 cm} -1 ~ 1520 cm ^-1 derived from an aromatic ring _(I E / _{I P)} contained, the ratio of the mixture of the epoxy resin and the curing agent (I _E / _{I P)} the difference between (a ratio of mixture _(I E / I _P) - the ratio of the surface _(I E _/ I P)) is, prepreg mica tape is 0.4 to 1.7.
<4> The prepreg mica tape according to any one of <1> to <3>, wherein the flexibility measured according to JIS C2116: 2011 is 200 N / m or less.
<5> The prepreg mica tape according to any one of <1> to <4>, wherein the backing layer further contains an inorganic filler.
<6> The prepreg mica tape according to <5>, wherein the inorganic filler contains boron nitride.
<7> The prepreg mica tape according to any one of <1> to <6>, wherein the curing agent contains a cationic species represented by the following general formula (I).

(In the general formula (I), R ¹ and R ² each independently represent an alkyl group, a phenyl group, a benzyl group, a naphthyl group or a naphthylmethyl group. R ³ independently represents an alkyl group, a hydroxy group, Carboxy group, alkoxy group, aryloxy group, alkylcarbonyl group, arylcarbonyl group, aralkylcarbonyl group, aralkylcarbonyl group, alkoxycarbonyl group, aryloxycarbonyl group, aralkyloxycarbonyl group, alkylcarbonyloxy group, arylcarbonyloxy group, aralkylcarbonyloxy group , Alkoxycarbonyloxy group, aryloxycarbonyloxy group, aralkyloxycarbonyloxy group, arylthiocarbonyl group, arylthio group, alkylthio group, aryl group, heterocyclic hydrocarbon group, alkylsulfinyl group And arylsulfinyl group, alkylsulfonyl group, arylsulfonyl group, alkylsulfonyloxy group, arylsulfonyloxy group, hydroxy (poly) alkyleneoxy group, amino group, cyano group, nitro group or halogen atom, n is 0 to 5 Indicates an integer.)
<8> The prepreg mica tape according to any one of <1> to <7>, which is wound in a roll so that the surface of the mica-containing layer is in contact with the surface of the backing layer.
<9> A separator further provided on at least one of the surface of the mica-containing layer and the surface of the backing layer is further provided, and the surface of the mica-containing layer and the surface of the backing layer are through the separator. The prepreg mica tape according to any one of <1> to <7>, wherein the prepreg mica tape is wound in a roll shape so as to contact.
<10> A coil conductor, and an insulating material including a cured product of a laminate of a prepreg mica tape according to any one of <1> to <9> and covering at least a part of the outer periphery of the coil conductor A coil for a rotating electrical machine having a layer.
<11> A step of forming a laminate of a prepreg mica tape according to any one of <1> to <9>, covering at least a part of the outer periphery of the coil conductor.
Curing the laminate of the prepreg mica tape to form an insulating layer;
The manufacturing method of the coil for rotary electric machines which has.

According to one aspect of the present invention, a prepreg mica tape capable of securing flexibility required for winding and suppressing surface adhesiveness, a coil for a rotating electrical machine using the same, and a method of manufacturing the same are provided.

It is IR spectrum obtained by Example 1 and Comparative Example 1.

Hereinafter, a form for carrying out a prepreg mica tape, a coil for a rotating electrical machine, and a method for manufacturing the same of the present invention will be described in detail. However, the present invention is not limited to the following disclosure. In the following disclosure, the constituent elements (including element steps and the like) are not essential unless otherwise specified. The same applies to numerical values and ranges thereof, and does not limit the present invention.
In the present disclosure, the term “step” includes, in addition to steps independent of other steps, such steps as long as the purpose of the step is achieved even if it can not be clearly distinguished from other steps. .
In the present disclosure, numerical values described before and after “to” are included in the numerical range indicated using “to” as the minimum value and the maximum value, respectively.
The upper limit value or the lower limit value described in one numerical value range may be replaced with the upper limit value or the lower limit value of the other stepwise description numerical value range in the numerical value range described stepwise in the present disclosure. . In addition, in the numerical range described in the present disclosure, the upper limit value or the lower limit value of the numerical range may be replaced with the value shown in the example.
In the present disclosure, each component may contain a plurality of corresponding substances. When a plurality of substances corresponding to each component are present in the composition, the content or content of each component is the total content or content of the plurality of substances present in the composition unless otherwise specified. Means quantity.
In the present disclosure, particles corresponding to each component may contain a plurality of types. When there are a plurality of particles corresponding to each component in the composition, the particle diameter of each component means the value for the mixture of the plurality of particles present in the composition unless otherwise specified.
In the present disclosure, the term “layer” may mean that when the region in which the layer is present is observed, it is formed in only a part of the region, in addition to the case where the region is entirely formed. included.
The term "laminate" in the present disclosure refers to stacking layers, two or more layers may be combined, and two or more layers may be removable.

<< Prepreg mica tape >>
The prepreg mica tape of the present disclosure comprises a mica-containing layer containing a thermosetting resin, a curing agent and mica, a thermosetting resin provided on one side of the mica-containing layer, a curing agent, and a backing material. And at least one of the surface of the mica-containing layer and the surface of the backing layer is more cured than the inner side in the thickness direction of the mica-containing layer and the backing layer The degree of cure of the thermosetting resin on at least one of the surface of the mica-containing layer and the surface of the backing layer may be 30% to 80% (hereinafter referred to as the second method). It may be referred to as a prepreg mica tape) or derived from an epoxy group contained in the epoxy resin on at least one of the surface of the mica-containing layer and the surface of the backing layer 1230 cm ^-1 ~ ratio of the absorbance _{I P} of peaks present in the range of ^{1500 cm} -1 ~ 1520 cm ^-1 derived from an aromatic ring contained in said epoxy resin absorbance _{I E} peaks present in the range of 1250 cm ^-1 ( and _{I E} / I _P), the epoxy resin and the _{(ratio (I} E / _{I P} for the difference (a mixture of _I E / I _P)) ratio for the mixture of curing agent - the ratio of the surface _(I E / I _P )) is 0.4 to 1.7 (hereinafter sometimes referred to as third prepreg mica tape).
Hereinafter, the first, second and third prepreg mica tapes may be collectively referred to simply as a prepreg mica tape.

-First prepreg mica tape-
In the first prepreg mica tape, at least one of the surface of the mica-containing layer and the surface of the backing layer is more cured than the inner side in the thickness direction of the mica-containing layer and the backing layer. When the first prepreg mica tape has such a configuration, the adhesiveness on at least one of the surface on the mica-containing layer side and the surface on the backing layer side of the first prepreg mica tape is suppressed. Therefore, the mica-containing layer and the backing layer can be easily separated from the state in which the surface of the mica-containing layer and the surface of the backing layer are in a roll shape so as to be in contact with each other. Moreover, the separator provided as needed can be easily pulled away from the mica containing layer or the backing layer. Furthermore, since the prepreg mica tape is kept to a curing degree that can suppress the adhesiveness on at least one of the surface on the mica-containing layer side and the surface on the backing layer side, it is possible to secure the flexibility necessary for winding. It is guessed.

In the first prepreg mica tape, the degree of curing on at least one of the surface of the mica-containing layer and the surface of the backing layer is not particularly limited, and the curing proceeds more than the inner side in the thickness direction of the mica-containing layer and the backing layer. It should be good. In the first prepreg mica tape, the degree of curing on one of the surface of the mica-containing layer and the surface of the backing layer may be more advanced than the degree of curing on the inner side in the thickness direction of the mica-containing layer and backing layer. The degree of curing on both the surface of the layer and the surface of the backing layer may be more advanced than the degree of curing on the inner side in the thickness direction of the mica-containing layer and the backing layer. If the degree of curing on both the surface of the mica containing layer and the surface of the backing layer is more advanced than the degree of curing on the inner side in the thickness direction of the mica containing layer and the backing layer, the degree of curing on the surface of the mica containing layer And the degree of curing on the surface of the backing layer may be the same or different.
The method for quantifying the degree of progress of curing is not particularly limited, and can be quantified by the degree of curing of the thermosetting resin described later.

When the degree of curing on at least one of the surface of the mica-containing layer and the surface of the backing layer is determined by the degree of curing of the thermosetting resin, the curing of the thermosetting resin on at least one of the surface of the mica-containing layer and the surface of the backing layer The degree is preferably 30% to 80%, more preferably 40% to 75%, and still more preferably 45% to 70%.
The degree of curing of the thermosetting resin on the surface of the mica-containing layer and the surface of the backing layer can be calculated by quantifying the amount of functional groups contributing to the curing reaction contained in the thermosetting resin by infrared spectroscopy. it can. When quantifying the functional group contributing to the curing reaction, it contributes to the curing reaction based on the ratio of the amount of the portion not contributing to the curing reaction contained in the thermosetting resin and the amount of the functional group contributing to the curing reaction. The amount of functional groups may be quantified.
When the thermosetting resin is an epoxy resin and the curing degree of the thermosetting resin on the surface of the mica-containing layer is quantified, it is derived from the epoxy group which is a functional group contributing to the curing reaction for the surface of the mica-containing layer to ^{1230 cm} -1 ~ and the absorbance _{I E} peaks present in the range of 1250 cm ^-1, the absorbance _{I P} of peaks present in the range of ^{1500 cm} -1 ~ 1520 cm ^-1 derived from the aromatic ring is a part that does not contribute to the curing reaction Is measured by infrared spectroscopy to calculate the ratio (I _E / I _P ). Let this be I ₁ . Next, a reference sample is prepared by separately mixing the epoxy resin and the curing agent contained in the mica-containing layer in the same proportion as in the mica-containing layer, and the ratio (I _E / I _P ) of the reference sample is described above Calculated by the same method. Let this be I ₀ . From the obtained I ₀ and I ₁ , calculate the degree of cure (%) of the thermosetting resin on the surface of the mica-containing layer as [(1- (I ₁ / I ₀ )) × 100 (%)] Can.
Specifically, an infrared absorption spectrum (IR spectrum) is measured with an infrared spectrophotometer (for example, BRUKER, ALPHA FT-IR Spectrometer resolution 4 cm ^-1 , scanning number 16 times, measurement wave number area 4000 to 400 cm ^-1 ) taking measurement. Absorbance of peaks present in the range of absorbance peak from the obtained IR spectrum is present in the range of ^{1230 cm} -1 ~ 1250 cm ^-1 and ^{1500 cm} -1 ~ 1520 cm ^-1 can be obtained.
When a thermosetting resin, for example, (meth) acrylic compound, in place of the peak derived from the epoxy group, for example, ^{1625 cm} -1 ~ 1645 cm ^-1 or ^{800 cm} -1 ~ 820 cm ^-1 attributed to the vinyl group The curing degree (%) of the thermosetting resin can be calculated in the same manner as in the case of the epoxy resin, based on the absorbance of the peak existing in the range of.

The degree of curing on the inner side in the thickness direction of the mica containing layer and the backing layer can be determined by the degree of curing of the thermosetting resin for the entire prepreg mica tape. The curing degree of the thermosetting resin for the entire prepreg mica tape can be calculated by quantifying the calorific value measured by differential scanning calorimetry (DSC) for the prepreg mica tape. The heat of reaction is detected from the prepreg mica tape was measured by DSC, which is referred to as A _1. Next, a reference sample is prepared by separately mixing the epoxy resin and the curing agent contained in the prepreg mica tape in the same proportion as that in the prepreg mica tape, and the reaction heat of the reference sample is measured by DSC. _{It is} assumed that ₀ . From the obtained A ₁ and A ₀ , the curing degree of the thermosetting resin for the entire prepreg mica tape can be calculated as [(1− (A ₁ / A ₀ )) × 100 (%)].
Comparing the curing degree of the thermosetting resin for the entire prepreg mica tape and the curing degree of the thermosetting resin on at least one of the surface of the mica-containing layer and the surface of the backing layer, the surface of the mica-containing layer and the backing layer If the degree of cure of the thermosetting resin on at least one of the surfaces is a high value, at least one of the surface of the mica-containing layer and the surface of the backing layer is cured more than the inner side in the thickness direction of the mica-containing layer and the backing layer. It can be determined that

-Second prepreg mica tape-
The second prepreg mica tape is such that the degree of curing of the thermosetting resin on at least one of the surface of the mica-containing layer and the surface of the backing layer is 30% to 80%. In the second prepreg mica tape, even if the degree of curing of the thermosetting resin on one of the surface of the mica-containing layer and the surface of the backing layer is 30% to 80%, the surface of the mica-containing layer and the surface of the backing layer The curing degree of the thermosetting resin in both may be 30% to 80%. When the curing degree of the thermosetting resin on both the surface of the mica-containing layer and the surface of the backing layer is 30% to 80%, the degree of curing of the thermosetting resin on the surface of the mica-containing layer and the surface of the backing layer The degree of curing of the thermosetting resin in may be the same or different.
When the second prepreg mica tape has such a configuration, the adhesiveness on at least one of the surface on the mica-containing layer side and the surface on the backing layer side of the second prepreg mica tape is suppressed. Therefore, the mica-containing layer and the backing layer can be easily separated from the state in which the surface of the mica-containing layer and the surface of the backing layer are in a roll shape so as to be in contact with each other. Moreover, the separator provided as needed can be easily pulled away from the mica containing layer or the backing layer. Furthermore, since the prepreg mica tape is kept to a curing degree that can suppress the adhesiveness on at least one of the surface on the mica-containing layer side and the surface on the backing layer side, it is possible to secure the flexibility necessary for winding. It is guessed.
The degree of cure of the thermosetting resin on at least one of the surface of the mica-containing layer and the surface of the backing layer is preferably 40% to 75%, and more preferably 45% to 70%.

In the second prepreg mica tape, the curing degree of the thermosetting resin on at least one of the surface of the mica-containing layer and the surface of the backing layer, and the curing degree of the thermosetting resin on the inner side in the thickness direction of the mica-containing layer and the backing layer And the curing degree of the thermosetting resin on at least one of the surface of the mica-containing layer and the surface of the backing layer may be high, and at least the surface of the mica-containing layer and the surface of the backing layer It is preferable that the curing degree of the thermosetting resin in one side is high. In the present disclosure, the value of the degree of cure of the thermosetting resin for the entire prepreg mica tape can be used as a value of the degree of cure of the thermosetting resin on the inner side in the thickness direction of the mica-containing layer and the backing layer.
The degree of cure (surface cure) of the thermosetting resin on the side of the surface of the mica containing layer and the surface of the backing layer where the degree of cure of the thermosetting resin is high, and the curing of the thermosetting resin for the entire prepreg mica tape The difference with the degree (total degree of cure) (surface degree of cure-total degree of cure) is preferably in the range of 30% to 65%, more preferably in the range of 35% to 60%, 40 More preferably, it is in the range of% to 60%.
The method of calculating the degree of curing of the thermosetting resin on the surface of the mica-containing layer and the surface of the backing layer in the second prepreg mica tape and the degree of curing of the thermosetting resin in the entire prepreg mica tape is the first prepreg. The same as in the case of mica tape.

-Third prepreg mica tape-
Third prepreg mica tape has a surface and at least one from the epoxy group contained in the epoxy resin at 1230 cm -1 of the peaks present in the range of ^~ 1250 cm ^-1 absorbance I _E of the surface of the backing layer of the mica-containing layer ratio for the ratio between the absorbance _{I P} of peaks present in the range of ^{1500 cm} -1 ~ 1520 cm ^-1 derived from an aromatic ring contained in the epoxy resin and _(I E / _{I P),} a mixture of epoxy resin and curing agent ( The difference with I _E / I _P ) (ratio for mixture (I _E / I _P ) —ratio at surface (I _E / I _P )) is between 0.4 and 1.7. The difference (ratio for the mixture (I _E / I _P ) -ratio at the surface (I _E / I _P )) is preferably between 0.5 and 1.7 and between 0.8 and 1.6 Is more preferable, and 1.0 to 1.5 is more preferable.
By the third prepreg mica tape having such a configuration, the adhesiveness on at least one of the surface on the mica-containing layer side and the surface on the backing layer side of the third prepreg mica tape is suppressed. Therefore, the mica-containing layer and the backing layer can be easily separated from the state in which the surface of the mica-containing layer and the surface of the backing layer are in a roll shape so as to be in contact with each other. Moreover, the separator provided as needed can be easily pulled away from the mica containing layer or the backing layer. Furthermore, since the prepreg mica tape is kept to a curing degree that can suppress the adhesiveness on at least one of the surface on the mica-containing layer side and the surface on the backing layer side, it is possible to secure the flexibility necessary for winding. It is guessed.

In a third prepreg mica tape, the ratio of the at least one surface of the surface and the backing layer of the mica-containing layer and _(I E _/ I _P), the ratio inside the thickness direction of the mica-containing layer and the backing layer (I E _/ I _P ) may be the same, or the ratio (I _E / I _P ) in at least one of the surface of the mica-containing layer and the surface of the backing layer may be low, and the surface of the mica-containing layer and the backing layer It is preferred that the ratio (I _E / I _P ) of at least one of the surfaces is low.
The ratio (I _E / I _P ) on the side of the surface of the mica containing layer and the surface of the backing layer on the low side (I _E / I _P ) and the ratio inside the thickness direction of the mica containing layer and the backing layer (I The difference between _E / I _P (the internal ratio (I _E / I _P ) —the ratio at the surface (I _E / I _P )) is preferably in the range of 0.20 to 1.0, The range of 0.25 to 0.95 is more preferable, and the range of 0.30 to 0.90 is more preferable.

The method of calculating the ratio (I _E / I _P ) of the surface of the mica-containing layer and the surface of the backing layer in the third prepreg mica tape is the same as that of the first prepreg mica tape. Further, the ratio (I _E / I _P ) in the thickness direction of the mica-containing layer and the backing layer in the third prepreg mica tape is the third prepreg by scraping the surface of either the mica-containing layer or the backing layer. in terms of exposing the interior of the mica tape in the same manner as in the first prepreg mica tape measure absorbance I _E and the absorbance I _P, it can be calculated.
Furthermore, the ratio (I _E / I _P ) for the mixture of epoxy resin and curing agent is calculated as in the case of calculating the ratio (I _E / I _P ) for the reference sample in the first prepreg mica tape. can do.

-Layer configuration of prepreg mica tape-
The layer configuration of the prepreg mica tape of the present disclosure is a mica-containing layer containing a thermosetting resin, a curing agent, and mica, a thermosetting resin, a curing agent, and a backing material provided on one surface of the mica-containing layer. As long as it has a backing layer containing and, if necessary, it may have other layers. Other layers include a separator (protective film), an adhesive layer, and the like provided on at least one of the surface of the mica-containing layer and the surface of the backing layer.

(Mica-containing layer)
The mica-containing layer according to the present disclosure contains a thermosetting resin, a curing agent, and mica. The mica-containing layer according to the present disclosure may contain other components other than mica, a thermosetting resin, and a curing agent, as needed. As other components, various additives can be mentioned, for example.
The thickness of the mica-containing layer is not particularly limited, and is preferably in the range of 100 μm to 250 μm, and more preferably in the range of 110 μm to 230 μm.
For the thickness of the mica-containing layer, observe a secondary electron image at an accelerating voltage of 10 kV under high vacuum after depositing platinum on a cross section of a prepreg mica tape using a scanning electron microscope (SEM) (for example, Philips, XL30) You can ask for it by doing.

The mica-containing layer preferably contains no other inorganic filler (such as boron nitride) other than mica, which is used as needed. 3 mass% or less is preferable, as for the content rate of other inorganic fillers other than mica which occupy the whole quantity of the inorganic filler contained in a mica containing layer, 2 mass% or less is more preferable, and 1 mass% or less is more preferable. And 0% by mass is particularly preferable.

(Backing layer)
The backing layer according to the present disclosure includes a thermosetting resin, a curing agent, and a backing material. The backing layer according to the present disclosure may optionally contain other components other than the backing material, the thermosetting resin and the curing agent. As other components, an inorganic filler, various additives, etc. can be mentioned, for example.
The thickness of the backing layer is not particularly limited, and is preferably in the range of 80 μm to 200 μm.
For the thickness of the backing layer, after depositing platinum on the cross section of the prepreg mica tape using a scanning electron microscope (SEM) (for example, Philips, XL30), observe a secondary electron image at an accelerating voltage of 10 kV under high vacuum It can be determined by

-Component material of prepreg mica tape-
Hereinafter, the backing material, the mica, the thermosetting resin, the curing agent, and other materials used as needed, which constitute the prepreg mica tape of the present disclosure, will be described.

(Backing material)
As the backing material used in the present disclosure, for example, a cloth obtained by using all or part of fibers made of an organic material may be used. Examples of the organic material used to obtain the cloth include aramid, polyamide, polyimide, polyester and the like. When a part of fibers composed of an organic material is used, the fibers composed of an organic material may be used as warp, weft or both. Inorganic fibers such as glass fibers may be used as fibers other than fibers composed of organic materials. A glass cloth using glass fiber and an organic polymer film may be used in combination. As the backing material, a glass cloth formed of glass fibers can also be used.

(Mica)
As the mica contained in the mica-containing layer, unfired hard mica, fired hard mica, unfired soft mica, fired soft mica, synthetic mica, flake mica, etc. can be used. Among these, it is preferable to use unfired hard mica as mica from the viewpoint of price and availability.
Further, from the viewpoint of improving the insulating property, it is preferable that the proportion of mica pieces having a particle diameter of 2.8 mm or more when sifted using a JIS standard sieve is 50% by mass or more, and 55% by mass The content is more preferably 60% by mass or more. If the proportion of mica pieces having a particle diameter of 2.8 mm or more is 50% by mass or more, mica paper can stand on its own even without fibrils. It is advantageous to the heat conductivity that it does not put fibrilt.

Specifically, the measurement of the particle size of the mica pieces is carried out according to the following method.
1% by mass of mica to be measured is added to 20 g of pure water, and the mica is dispersed by an ultrasonic dispersion machine to prepare a dispersion. After the dispersion is applied on the film, the film is placed on a hot plate and dried at 110 ° C. for 30 minutes. After drying, the particle size of mica is measured by visually observing the size of mica pieces on the film.
Moreover, the ratio (mass reference | standard) of the mica piece whose particle diameter is 2.8 mm or more is measured by the following method.
Using a JIS standard sieve with an aperture of 2.8 mm, equipped with a low-tapping sieve vibrator, pass 1.2 g of mica through the sieve while vibrating (the number of hammer strokes: 60 times / minute) over 15 minutes. The ratio (mass standard) of mica pieces of 2.8 mm or more is determined from the ratio of coarse particles remaining on the sieve of 2.8 mm with respect to the sample weight before classification.

In the present disclosure, one type of mica may be used alone, or two or more types may be used in combination. When two or more types of mica are used in combination, for example, when two or more types of mica having the same component but different average particle sizes are used, the case where two or more types of mica having the same average particle size but different components are used, and the average particle size and There are cases where two or more kinds of different types of mica are used.

(Thermosetting resin)
As the thermosetting resin used in the present disclosure, epoxy resin, phenol resin, urea resin, melamine resin, unsaturated polyester resin, cyanate ester resin, polyimide resin, bismaleimide triazine resin, phenol aralkyl resin, etc. It can be used alone or in combination of two or more.
Among the thermosetting resins, epoxy resins are preferred. As the epoxy resin, for example, bisphenol A epoxy resin, bisphenol F epoxy resin, phenol novolac epoxy resin, cresol novolac epoxy resin and alicyclic epoxy resin can be used alone or in combination of two or more kinds. .
In the prepreg mica tape of the present disclosure, the thermosetting resin contained in the mica-containing layer and the thermosetting resin contained in the backing layer may be the same or different, and are preferably the same.

(Hardening agent)
The curing agent used in the present disclosure is not particularly limited, and conventionally known curing agents used for curing the thermosetting resin can be selected and used according to the type of the thermosetting resin.
When an epoxy resin is used as the thermosetting resin, the curing agent may include a curing agent containing a cationic species represented by the following general formula (I) (hereinafter, may be referred to as a specific curing agent). Is preferred.

In General Formula (I), R ¹ and R ² each independently represent an alkyl group, a phenyl group, a benzyl group, a naphthyl group or a naphthylmethyl group. Each R ³ independently represents an alkyl group, a hydroxy group, a carboxy group, an alkoxy group, an aryloxy group, an alkylcarbonyl group, an arylcarbonyl group, an aralkylcarbonyl group, an alkoxycarbonyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, an aralkyloxycarbonyl group, Alkyl carbonyloxy group, aryl carbonyloxy group, aralkyl carbonyloxy group, alkoxy carbonyloxy group, aryloxy carbonyloxy group, aralkyl oxy carbonyloxy group, arylthio carbonyl group, arylthio group, alkylthio group, aryl group, heterocyclic carbonization Hydrogen group, alkylsulfinyl group, arylsulfinyl group, alkylsulfonyl group, arylsulfonyl group, alkylsulfonyloxy group, arylsulfonyloxy group, Hydroxy (poly) alkylene oxy group, amino group, cyano group, nitro group or halogen atom is shown. n is an integer of 0 to 5;

In the general formula (I), examples of the alkyl group represented by R ¹ to R ³ include a linear alkyl group having 1 to 18 carbon atoms, a branched alkyl group having 1 to 18 carbon atoms, and a cycloalkenyl having 3 to 18 carbon atoms. An alkyl group etc. are mentioned.
Specific examples of the linear alkyl group having 1 to 18 carbon atoms include methyl group, ethyl group, n-propyl group, n-butyl group, n-pentyl group, n-octyl group, n-decyl group and n-dodecyl group. Groups, n-tetradecyl group, n-hexadecyl group, n-octadecyl group and the like.
Specific examples of the branched alkyl group having 1 to 18 carbon atoms include an isopropyl group, an isobutyl group, a sec-butyl group, a t-butyl group, an isopentyl group, a neopentyl group, a t-pentyl group, an isohexyl group and an isooctadecyl group. Etc.
Specific examples of the cycloalkyl group having 3 to 18 carbon atoms include cyclopropyl group, cyclobutyl group, cyclopentyl group, cyclohexyl group, 4-decylcyclohexyl group and the like.

Examples of the alkoxy group represented by R ³ in the general formula (I) include a linear or branched alkoxy group having 1 to 18 carbon atoms.
Specifically as an alkoxy group, a methoxy group, an ethoxy group, a propoxy group, an isopropoxy group, a butoxy group, an isobutoxy group, a sec-butoxy group, a t-butoxy group, a hexyloxy group, a decyloxy group, a dodecyloxy group, an octadecyloxy group. And the like.

Examples of the aryloxy group represented by R ³ in the general formula (I) include aryloxy groups having 6 to 10 carbon atoms.
Specific examples of the aryloxy group include phenoxy group and naphthyloxy group.

In the general formula (I), examples of the alkylcarbonyl group represented by R ³ include linear or branched alkylcarbonyl groups having 2 to 18 carbon atoms.
Specifically as an alkylcarbonyl group, an acetyl group, a propionyl group, a butanoyl group, a 2-methylpropionyl group, a heptanoyl group, a 2-methylbutanoyl group, a 3-methylbutanoyl group, an octanoyl group, a decanoyl group, a dodecanoyl group, Octadecanoyl group etc. are mentioned.

In the general formula (I), examples of the arylcarbonyl group represented by R ³ include arylcarbonyl groups having 7 to 11 carbon atoms.
Specific examples of the arylcarbonyl group include benzoyl group and naphthoyl group.

Examples of the aralkylcarbonyl group represented by R ³ in the general formula (I) include lower alkylcarbonyl groups substituted with an aryl group having 6 to 10 carbon atoms.
Specific examples of the aralkylcarbonyl group include benzylcarbonyl group, 2-methylbenzylcarbonyl group, 1-naphthylmethylcarbonyl group, 2-naphthylmethylcarbonyl group and the like.

Examples of the alkoxycarbonyl group represented by R ³ in the general formula (I) include a linear or branched alkoxycarbonyl group having 2 to 19 carbon atoms.
Specific examples of the alkoxycarbonyl group include methoxycarbonyl, ethoxycarbonyl, propoxycarbonyl, isopropoxycarbonyl, butoxycarbonyl, isobutoxycarbonyl, sec-butoxycarbonyl, t-butoxycarbonyl, octyloxycarbonyl Groups, tetradecyloxycarbonyl group, octadecyloxycarbonyl group and the like.

Examples of the aryloxycarbonyl group represented by R ³ in the general formula (I) include an aryloxycarbonyl group having 7 to 11 carbon atoms.
Specific examples of the aryloxycarbonyl group include phenoxy carbonyl group and naphthoxycarbonyl group.

In the general formula (I), examples of the aralkyloxycarbonyl group represented by R ³ include a lower alkoxycarbonyl group substituted with an aryl group having 6 to 10 carbon atoms.
Specific examples of the aralkyloxycarbonyl group include benzyloxycarbonyl group, 2-methylbenzyloxycarbonyl group, 1-naphthylmethyloxycarbonyl group, 2-naphthylmethyloxycarbonyl group and the like.

In the general formula (I), examples of the alkylcarbonyloxy group represented by R ³ include linear or branched alkylcarbonyloxy groups having 2 to 19 carbon atoms.
Specifically as an alkyl carbonyloxy group, an acetoxy group, an ethyl carbonyloxy group, a propyl carbonyloxy group, an isopropyl carbonyloxy group, a butyl carbonyloxy group, an isobutyl carbonyloxy group, a sec-butyl carbonyloxy group, a t-butyl carbonyloxy group Groups, octyl carbonyloxy group, tetradecyl carbonyloxy group, octadecyl carbonyloxy group and the like.

Examples of the arylcarbonyloxy group represented by R ³ in the general formula (I) include arylcarbonyloxy groups having 7 to 11 carbon atoms.
Specific examples of the arylcarbonyloxy group include benzoyloxy group and naphthoyloxy group.

In the general formula (I), examples of the aralkylcarbonyloxy group represented by R ³ include lower alkylcarbonyloxy groups substituted with aryl groups having 6 to 10 carbon atoms.
Specific examples of the aralkylcarbonyloxy group include benzylcarbonyloxy group, 2-methylbenzylcarbonyloxy group, 1-naphthylmethylcarbonyloxy group, 2-naphthylmethylcarbonyloxy group and the like.

Examples of the alkoxycarbonyloxy group represented by R ³ in the general formula (I) include a linear or branched alkoxycarbonyloxy group having 2 to 19 carbon atoms.
Specific examples of the alkoxycarbonyloxy group include methoxycarbonyloxy group, ethoxycarbonyloxy group, propoxycarbonyloxy group, isopropoxycarbonyloxy group, butoxycarbonyloxy group, isobutoxycarbonyloxy group, sec-butoxycarbonyloxy group, t And -butoxycarbonyloxy group, octyloxycarbonyloxy group, tetradecyloxycarbonyloxy group, octadecyloxycarbonyloxy group and the like.

Examples of the aryloxycarbonyloxy group represented by R ³ in the general formula (I) include an aryloxycarbonyloxy group having 7 to 11 carbon atoms.
Specific examples of the aryloxycarbonyloxy group include phenoxycarbonyloxy group and naphthoxycarbonyloxy group.

In the general formula (I), examples of the aralkyloxycarbonyloxy group represented by R ³ include lower alkoxycarbonyloxy groups substituted with an aryl group having 6 to 10 carbon atoms.
Specific examples of the aralkyloxycarbonyloxy group include benzyloxycarbonyloxy group, 2-methylbenzyloxycarbonyloxy group, 1-naphthylmethyloxycarbonyloxy group, 2-naphthylmethyloxycarbonyloxy group and the like.

Examples of the arylthiocarbonyl group represented by R ³ in the general formula (I) include arylthiocarbonyl groups having 7 to 11 carbon atoms.
Specific examples of the arylthiocarbonyl group include phenylthiocarbonyl group and naphthylthiocarbonyl group.

Examples of the arylthio group represented by R ³ in the general formula (I) include arylthio groups having 6 to 20 carbon atoms.
Specific examples of the arylthio group include phenylthio group, 2-methylphenylthio group, 3-methylphenylthio group, 4-methylphenylthio group, 2-chlorophenylthio group, 3-chlorophenylthio group, 4-chlorophenylthio group, 2-bromophenylthio group, 3-bromophenylthio group, 4-bromophenylthio group, 2-fluorophenylthio group, 3-fluorophenylthio group, 4-fluorophenylthio group, 2-hydroxyphenylthio group, 4 -Hydroxyphenylthio group, 2-methoxyphenylthio group, 4-methoxyphenylthio group, 1-naphthylthio group, 2-naphthylthio group, 4- [4- (phenylthio) benzoyl] phenylthio group, 4- [4- (phenylthio) group ) Phenoxy] phenylthio group, 4- [4- (phenylthio) phenyl] 4- (phenylthio) phenylthio group, 4-benzoylphenylthio group, 4-benzoyl-2-chlorophenylthio group, 4-benzoyl-3-chlorophenylthio group, 4-benzoyl-3-methylthiophenylthio group, 4 -Benzoyl-2-methylthiophenylthio group, 4- (4-methylthiobenzoyl) phenylthio group, 4- (2-methylthiobenzoyl) phenylthio group, 4- (p-methylbenzoyl) phenylthio group, 4- (p-ethylbenzoyl) And the like), phenylthio group, 4- (p-isopropylbenzoyl) phenylthio group, 4- (pt-butylbenzoyl) phenylthio group and the like.

In the general formula (I), examples of the alkylthio group represented by R ³ include linear or branched alkylthio groups having 1 to 18 carbon atoms.
Specific examples of the alkylthio group include methylthio group, ethylthio group, propylthio group, isopropylthio group, butylthio group, isobutylthio group, sec-butylthio group, t-butylthio group, pentylthio group, isopentylthio group, neopentylthio group. And t-pentylthio group, octylthio group, decylthio group, dodecylthio group, isooctadecylthio group and the like.

Examples of the aryl group represented by R ³ in the general formula (I) include aryl groups having 6 to 10 carbon atoms.
Specific examples of the aryl group include phenyl group, tolyl group, dimethylphenyl group and naphthyl group.

Examples of the heterocyclic hydrocarbon group represented by R ³ in the general formula (I) include heterocyclic hydrocarbon groups having 4 to 20 carbon atoms.
Specific examples of the heterocyclic hydrocarbon group include thienyl group, furanyl group, pyranyl group, pyrrolyl group, oxazolyl group, thiazolyl group, pyridyl group, pyrimidyl group, pyrazinyl group, indolyl group, benzofuranyl group, benzothienyl group, quinolyl. Group, isoquinolyl group, quinoxalinyl group, quinazolinyl group, carbazolyl group, acridinyl group, phenothiazinyl group, phenazinyl group, xanthenyl group, tianthrenyl group, phenoxazinyl group, phenoxatinyl group, chromanyl group, isochromanyl group, dibenzothienyl group, xanthonyl group Groups, thioxanthonyl groups, dibenzofuranyl groups and the like.

In the general formula (I), examples of the alkylsulfinyl group represented by R ³ include linear or branched alkylsulfinyl groups having 1 to 18 carbon atoms.
Specific examples of the alkylsulfinyl group include methylsulfinyl group, ethylsulfinyl group, propylsulfinyl group, isopropylsulfinyl group, butylsulfinyl group, isobutylsulfinyl group, sec-butylsulfinyl group, t-butylsulfinyl group, pentylsulfinyl group, iso Examples thereof include pentylsulfinyl group, neopentylsulfinyl group, t-pentylsulfinyl group, octylsulfinyl group, isooctadecylsulfinyl group and the like.

In the general formula (I), examples of the arylsulfinyl group represented by R ³ include arylsulfinyl groups having 6 to 10 carbon atoms.
Specific examples of the arylsulfinyl group include phenylsulfinyl group, tolylsulfinyl group, and naphthylsulfinyl group.

In the general formula (I), examples of the alkylsulfonyl group represented by R ³ include a linear or branched alkylsulfonyl group having 1 to 18 carbon atoms.
Specific examples of the alkylsulfonyl group include methylsulfonyl group, ethylsulfonyl group, propylsulfonyl group, isopropylsulfonyl group, butylsulfonyl group, isobutylsulfonyl group, sec-butylsulfonyl group, t-butylsulfonyl group, pentylsulfonyl group, iso Examples thereof include pentyl sulfonyl group, neopentyl sulfonyl group, t-pentyl sulfonyl group, octyl sulfonyl group, octadecyl sulfonyl group and the like.

Examples of the arylsulfonyl group represented by R ³ in the general formula (I) include an arylsulfonyl group having 6 to 10 carbon atoms.
Specific examples of the arylsulfonyl group include phenylsulfonyl group, tolylsulfonyl group (tosyl group), and naphthylsulfonyl group.

In the general formula (I), examples of the alkylsulfonyloxy group represented by R ³ include linear or branched alkylsulfonyloxy groups having 1 to 18 carbon atoms.
Specifically, as the alkylsulfonyloxy group, methylsulfonyloxy group, ethylsulfonyloxy group, propylsulfonyloxy group, isopropylsulfonyloxy group, butylsulfonyloxy group, isobutylsulfonyloxy group, sec-butylsulfonyloxy group, t-butyl A sulfonyloxy group, a pentyl sulfonyloxy group, an isopentyl sulfonyloxy group, a neopentyl sulfonyloxy group, a t-pentyl sulfonyloxy group, an octyl sulfonyloxy group, an octadecyl sulfonyloxy group and the like can be mentioned.

Examples of the arylsulfonyloxy group represented by R ³ in the general formula (I) include an arylsulfonyloxy group having 6 to 10 carbon atoms.
Specific examples of the arylsulfonyloxy group include phenylsulfonyloxy group, tolylsulfonyloxy group, and naphthylsulfonyloxy group.

In the general formula (I), as the hydroxy (poly) alkyleneoxy group represented by R ³ , [HO (-AO) _q- (AO represents at least one of an ethyleneoxy group and a propyleneoxy group, and q is 1 to The integer of 5 is shown.)], Etc. are mentioned.

In the general formula (I), examples of the amino group represented by R ³ include an amino group (—NH ₂ ), a substituted amino group having 1 to 15 carbon atoms, and the like.
Specifically as a substituted amino group, methylamino group, dimethylamino group, ethylamino group, methylethylamino group, diethylamino group, n-propylamino group, methyl-n-propylamino group, ethyl-n-propylamino group Isopropylamino, isopropylmethylamino, isopropylethylamino, diisopropylamino, phenylamino, diphenylamino, methylphenylamino, ethylphenylamino, n-propylphenylamino, isopropylphenylamino and the like It can be mentioned.

Examples of the halogen atom represented by R ³ in the general formula (I) include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom.

In the formula (1), n represents the number of R ³ and is preferably an integer of 0 to 5, more preferably 0 to 3, still more preferably 0 to 2, particularly preferably 0 or 1 It is.

Each group represented by R ¹ to R ³ may further have a substituent. Specific examples of the substituent include an alkyl group, an aryl group, an amino group, a cyano group, a nitro group, a halogen atom and the like.

The cationic species represented by the general formula (I) is preferably a cationic species represented by the general formula (II).

In the general formula (II), R ¹ represents an alkyl group having 1 to 4 carbon atoms, a benzyl group, a naphthyl group or a naphthylmethyl group, and R ² represents an alkyl group having 1 to 4 carbon atoms. R ⁴ is a hydrogen atom, R-CO- group or R-SO ₂ -group (R represents an alkyl group having 1 to 4 carbon atoms which may be substituted by one or more halogen atoms). Show. Each R ⁵ independently represents an alkyl group having 1 to 4 carbon atoms or a halogen atom. m is an integer of 0 to 4;

In the general formula (II), specific examples of the alkyl group having 1 to 4 carbon atoms in R ¹ , R ² , R ⁴ or R ⁵ include methyl, ethyl, n-propyl, isopropyl and n- Examples thereof include a butyl group, an isobutyl group, a sec-butyl group and a t-butyl group. m is an integer of 0 to 4, preferably 0 to 3, more preferably 0 to 2, and still more preferably 0 or 1.

In the general formula (II), R ⁴ is an R-CO- group or an R-SO ₂ -group (R is an alkyl group having 1 to 4 carbon atoms which may be substituted with one or more halogen atoms Is preferable, and R-CO- group is more preferable. The R-CO- group represented as R ⁴ is more preferably an acetyl group.
When R ⁴ is an R-CO- group, specific examples of the R ⁴ O- group are those having 2 to 5 carbon atoms of the specific examples when R ³ in the general formula (I) is an alkylcarbonyloxy group It is similar to Also, specific examples of the R ⁴ O- group when R ⁴ is a R-SO ₂ -group are the carbon numbers of the specific examples when R ³ in the general formula (I) is an alkylsulfonyloxy group It is similar to that of 1 to 4.

In the general formula (I) or the general formula (II), R ¹ is preferably an alkyl group, a naphthyl group or a naphthylmethyl group, more preferably an alkyl group having 1 to 4 carbon atoms, and a methyl group It is further preferred that
In general formula (I) or general formula (II), the preferable combination of ^{R 1} and ^{R 2, R 1} and ^{R 2} are both include a combination of a methyl group.

It does not specifically limit as an anionic species which makes a pair with the cationic species contained in the specific curing agent, for example, SbF ₆ ⁻ , PF ₆ ⁻ , BF ₄ ⁻ and (R f) _b PF _{6 − b} ⁻ (R f is And b represents an integer of 1 to 5). _{(Rf) b PF 6-b} - in Rf may each be the same or different.
As Rf, CF ₃ , C ₂ F ₅ , (CF ₃ ) ₂ CF, C ₃ F ₇ , C ₄ F ₉ , (CF ₃ ) ₂ CFCF ₂ , CF ₃ CF ₂ (CF ₃ ) CF, (CF ₃ ) A linear or branched alkyl group having 1 to 4 carbon atoms (perfluoroalkyl group) in which 100% of hydrogen atoms are substituted by fluorine atoms, such as ₃ C, may be used. _{(Rf) b PF 6-b} - The (fluorinated alkyl fluorophosphate _{ion), [(C 2 F 5} ) 3 PF 3] -, [(C 3 F 7) 3 PF 3] -, [(( CF ₃ ) ₂ CF) ₃ PF ₃ ] ^- , [((CF ₃ ) ₂ CF) ₂ PF ₄ ] ^- , [(CF ₃ ) ₂ CFCF ₂ ) ₃ PF ₃ ] ^- , [((CF ₃ ) ₂ ) CFCF _{2) 2} PF _4] ^-, and the like.
Examples of the anionic species, SbF ₆ from the viewpoint of stability of the curing agent ^- preferably a.

Specific examples of the specific curing agent include dimethyl-p-acetoxyphenylsulfonium = hexafluoroantimonate, hydroxyphenylmethylbenzylsulfonium = hexafluoroantimonate, dimethylacetoxyphenylsulfonium = fluorinated alkyl fluorophosphate and the like.

As a curing agent, other curing agents other than the specific curing agent may be used. Other curing agents include boron trifluoride amine complex, imidazole, dicyandiamide and the like.
The ratio of the specific curing agent to the curing agent is preferably 0% by mass to 100% by mass, more preferably 50% by mass to 100% by mass, and further preferably 90% by mass to 100% by mass. preferable.

The content of the curing agent is not particularly limited. The ratio of the curing agent to the thermosetting resin is preferably 0.001 to 5.0 in mass ratio (curing agent / thermosetting resin). From the viewpoint of increasing the glass transition temperature of the cured product, it is more preferable to be 0.004 to 5.0, and from the viewpoint of increasing the gel time, it is more preferable to be 0.004 to 1.5, and the catalyst From the viewpoint of reducing the amount used, it is particularly preferable to set it as 0.004 to 1.0.

(Inorganic filler)
The backing layer in the prepreg mica tape of the present disclosure may contain an inorganic filler to improve the thermal conductivity. The inorganic filler is preferably at least one selected from the group consisting of alumina, magnesium oxide, beryllium oxide, boron nitride, aluminum nitride, silicon nitride, silicon carbide, aluminum fluoride and calcium fluoride. Silica can also be used as the inorganic filler.

The average particle diameter of the inorganic filler is preferably 1 μm to 40 μm, more preferably 5 μm to 20 μm, and still more preferably 5 μm to 10 μm.
When the average particle diameter of the inorganic filler is 1 μm or more, the thermal conductivity and the insulation withstand voltage tend to be further improved. It can suppress that the anisotropy of the heat conductivity by the anisotropy of particle shape becomes it large that the average particle diameter of an inorganic filler is 40 micrometers or less.

The average particle diameter of the inorganic filler can be measured by using a laser diffraction scattering particle size distribution measuring apparatus (for example, Microtrac MT3000II, Nikkiso Co., Ltd.). After charging the inorganic filler into pure water, it is dispersed by an ultrasonic dispersion machine. The particle size distribution of the inorganic filler is measured by measuring the particle size distribution of the dispersion. Based on the particle size distribution, the average particle size is determined as the particle size corresponding to 50% of the volume accumulation from the small diameter side.

When the backing layer contains an inorganic filler, the content of the inorganic filler is 10% by volume to 50% by volume based on the total amount of the solid content excluding the backing material and mica contained in the prepreg mica tape Is preferable, and more preferably 15% by volume to 35% by volume. If the content of the inorganic filler is 10% by volume or more, the thermal conductivity of the prepreg mica tape tends to be further improved. If the content of the inorganic filler is 50% by volume or less, the filling of the inorganic filler into the resin tends to be difficult.

One type of inorganic filler may be used alone, or two or more types may be used in combination. When two or more types of inorganic fillers are used in combination, for example, when two or more types of inorganic fillers having the same component and different average particle sizes are used, two or more types of inorganic fillers having the same average particle size and different components are used. In some cases, two or more types of inorganic fillers having different average particle sizes and types are used.

Among these, it is preferable to contain boron nitride as an inorganic filler. Boron nitride is a material that can be used as a sliding wear material, and the surface of the backing layer containing boron nitride is highly slippery, and is effective in suppressing the adhesion of the backing layer surface.
If the backing layer comprises boron nitride, the prepreg mica tape can have high thermal conductivity and combine good flexibility and high dielectric strength. The reason for the prepreg mica tape having a backing layer containing boron nitride to have high thermal conductivity and to have both good flexibility and high insulation withstand voltage is not clear, but is presumed as follows.
Since boron nitride is an inorganic filler exhibiting high thermal conductivity, a prepreg mica tape having a backing layer containing boron nitride is presumed to have high thermal conductivity.
In addition, since the hardness of boron nitride is about half or less compared to that of alumina, it is surmised that it exhibits better flexibility as compared to a prepreg mica tape using alumina as a high thermal conductivity inorganic filler. Ru.
Furthermore, by separately providing the boron nitride-containing backing layer and the mica-containing layer, it is possible to prevent the boron nitride particles from being mixed between the mica pieces. When the boron nitride particles are mixed between the mica pieces, the current path may be shortened and the insulation withstand voltage of the prepreg mica tape may be lowered. However, by containing boron nitride in the backing layer, it is possible to prevent the boron nitride particles from mixing between the mica pieces, so the current path is unlikely to be short. Therefore, it is surmised that a prepreg mica tape having a backing layer containing boron nitride has a high insulation withstand voltage.

Examples of boron nitride include hexagonal boron nitride (h-BN), cubic boron nitride (c-BN), wurtzite boron nitride and the like. Among these, hexagonal boron nitride (h-BN) is preferable. The boron nitride may be a primary particle of boron nitride formed in a scaly shape or a secondary particle formed by aggregating such primary particles.

The content of boron nitride in the total amount of the inorganic filler is preferably 90% by mass to 100% by mass, more preferably 95% by mass to 100% by mass, and 98% by mass to 100% by mass. Is more preferred.

(Additive)
The additives used in the present disclosure may include various additives generally used in resin compositions, such as coupling agents, elastomers, antioxidants, anti-aging agents, stabilizers, flame retardants, thickeners and the like. it can. The content of these additives is not particularly limited as long as the effects of the present disclosure are not impaired.
In addition, a curing retarder can be used for the purpose of suppressing the curing rate of the curing agent. The content of the curing retarder can be appropriately set according to the curing rate, and is not particularly limited as long as the effects of the present disclosure are not impaired.

(Physical properties of prepreg mica tape)
The flexibility of the prepreg mica tape measured in accordance with JIS C2116: 2011 is preferably 200 N / m or less, and 150 N / m or less from the viewpoint of ease of taping work using the prepreg mica tape. It is more preferable that the ratio be 120 N / m or less. Moreover, the softness | flexibility measured based on JISC2116: 2011 of a prepreg mica tape may be 40 N / m or more.

The thickness of the prepreg mica tape is preferably 200 μm to 400 μm, and more preferably 250 μm to 350 μm.
The average thickness of the prepreg mica tape is obtained by measuring the thickness of 10 points using a micrometer (for example, MDC-SB, Mitutoyo Co., Ltd.) and calculating the arithmetic average value thereof.

-Shape of prepreg mica tape-
The prepreg mica tape of the present disclosure may be wound in a roll so that the surface of the mica-containing layer is in contact with the surface of the backing layer. The prepreg mica tape of the present disclosure further includes a separator provided on at least one of the surface of the mica-containing layer and the surface of the backing layer, and the surface of the mica-containing layer and the surface of the backing layer are separated via the separator. It may be wound in a roll shape so as to be in contact.
As the separator, polyethylene film, non-woven fabric, glass cloth or the like can be used.

When the prepreg mica tape of the present disclosure in a state of being wound up in a roll shape so that the surface of the mica containing layer is in contact with the surface of the backing layer, for example, the laminate of prepreg mica tape is wound around the outer periphery of the coil conductor. At the time of the taping operation to be formed, it is possible to prevent the fragments of the separator from being mixed into the laminate of the prepreg mica tape. Therefore, the deterioration of the electrical characteristics of the insulating layer due to the mixture of the separators hardly occurs. In addition, since an additional device for removing the separator is not necessary, the winding operation is less likely to be complicated when forming a laminate of prepreg mica tapes.
When using the prepreg mica tape of the present disclosure, which is wound in a roll so that the surface of the mica-containing layer and the surface of the backing layer are in contact with each other via the separator, the thermosetting properties included in the mica-containing layer and the backing layer It becomes difficult for the resin to adhere to the separator. Therefore, when the separator is disposed of, it becomes easy to recycle.

-Manufacturing method of prepreg mica tape-
The prepreg mica tape may be produced through any process, and a conventionally known production method can be applied.
As an example of a method of producing a prepreg mica tape, a resin varnish preparing step of preparing a resin varnish in which a thermosetting resin, a curing agent, and an inorganic filler and other materials used as necessary are mixed in a solvent, and a resin The method includes an application step of applying a varnish on one side of the backing material, and a sticking step of bonding mica paper to the side of the backing material on which the resin varnish is applied.
Another example of a method for producing a prepreg mica tape is a resin varnish preparing step of preparing a resin varnish in which a thermosetting resin, a curing agent, and an inorganic filler and other materials used as needed are mixed in a solvent The method includes a laminating step of laminating a backing material and mica paper to obtain a laminate, and an applying step of applying a resin varnish from the backing material side of the laminate.
The method of producing the prepreg mica tape may be a method of drying the prepreg mica tape.

There is no particular limitation on the method of setting the degree of curing on at least one of the surface of the mica containing layer and the surface of the backing layer to a state in which the degree of curing on the inner side in the thickness direction of the mica containing layer and the backing layer is advanced. For example, when drying a pre-preg mica tape which has been subjected to an attaching step of attaching mica paper or an applying step of applying a resin varnish, hot air may be applied to either the surface of the mica containing layer or the surface of the backing layer. . In addition, when the specific curing agent has thermosetting as well as photo-curing properties, either the surface of the mica-containing layer or the surface of the backing layer may be irradiated with light.

When the resin varnish contains an inorganic filler, the thermosetting resin may be diluted with a solvent in order to fill the thermosetting resin with the inorganic filler. As a solvent to be used, it is suitably selected from the organic solvent used normally. Specifically, solvents such as methyl ethyl ketone, methanol and cyclohexanone can be mentioned.

When the resin varnish contains an inorganic filler, the resin varnish is applied to one side of the backing material in the coating step, and the resin varnish is dried to form a backing layer containing the inorganic filler. The mica paper bonded to the coated side of the resin varnish in the backing material is impregnated with the thermosetting resin and the curing agent contained in the resin varnish, and other materials used as needed. The portion that was the paper is regarded as the mica-containing layer.

The thermosetting resin and the curing agent in the mica-containing layer and the thermosetting resin and the curing agent in the backing layer, both of which are contained in the resin varnish, included in the prepreg mica tape produced by the above-mentioned production method It is of the same type originating from the curable resin and the curing agent.

The prepreg mica tape of the present disclosure can be used to form an insulating layer of a coil conductor. The prepreg mica tape of the present disclosure can also be used as a heat-resistant, electrically-insulated, heat-radiating spacer, for example, as a material for improving the heat radiation of an insulating plate for heat dissipation of a power transistor.

<< Coil for electric rotating machine >>
The coil for a rotating electrical machine of the present disclosure has a coil conductor, and an insulating layer including a cured product of the laminate of the prepreg mica tape of the present disclosure and covering at least a part of the outer periphery of the coil conductor.
The material, shape, size and the like of the coil conductor used for the coil for a rotating electrical machine of the present disclosure are not particularly limited, and can be selected according to the application and the like of the coil for a rotating electrical machine.

<< Method of manufacturing coil for rotary electric machine >>
The method of manufacturing a coil for a rotating electrical machine according to the present disclosure comprises the steps of forming a laminate of the prepreg mica tape of the present disclosure covering at least a part of the outer periphery of the coil conductor, curing the laminate of the prepreg mica tape and insulating Forming a layer.
The process in particular of forming the laminated body of a prepreg mica tape is not restrict | limited, The method normally performed can be employ | adopted. For example, there is a method of winding mica tape around the outer periphery of the coil conductor. In this case, the prepreg mica tape may be wound multiple times so that parts (for example, a half of the width of the prepreg mica tape) overlap each other.
The step of forming the insulating layer is not particularly limited, and a method which is usually performed can be employed. For example, a thermosetting resin is cured by heating and pressing a coil conductor covered at least a part of the outer periphery with a laminate of a prepreg mica tape or after vacuum treatment, thereby curing a thermosetting resin and a prepreg mica tape Are integrated to form an insulating layer.

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

Example 1
(1) Preparation of mica paper The assembled mica was dispersed in water to make mica particles, and made into paper by a paper machine to prepare mica paper having a mica content of 160 g / m ² .

(2) Preparation of resin varnish As a thermosetting resin, epoxy novolac resin (Dow Chemical Japan Ltd., trade name "D.E.N. 438"("D.E.N." is a registered trademark.)) 143 parts by mass, 1 part by mass of dimethyl-p-acetoxyphenylsulfonium = hexafluoroantimonate as a curing agent, and 173 parts by mass of methyl ethyl ketone (MEK) (Wako Pure Chemical Industries, Ltd.) as an organic solvent were mixed. Thereafter, 143 parts by mass of boron nitride (average particle diameter: 5 μm, Denka Co., trade name “SP-3”) was added and further mixed to prepare a resin varnish.

(3) Preparation of Prepreg Mica Tape A glass cloth ("SOA 03G 103") was overlaid on mica paper, and the resin varnish obtained from the glass cloth side was applied by a roll coater. After the application, it was dried at 135 ° C. for 20 minutes to remove the solvent to obtain a prepreg mica tape. At this time, the solvent was removed in such a manner that hot air was applied to the glass cloth side (the surface of the backing layer).

(4) Preparation of hardened | cured material of prepreg mica tape The prepreg mica tape obtained by the above-mentioned method was heated at 170 degreeC for 10 hours, and the hardened | cured material of prepreg mica tape was manufactured.

<Evaluation>
The following evaluation was performed about the hardened | cured material of a prepreg mica tape and a prepreg mica tape. The results are shown in Table 1.

(1) IR spectrum measurement A mica-containing layer side of prepreg mica tape is brought into close contact with an ATR prism, and an infrared spectrophotometer (BRUKER, ALPHA FT-IR Spectrometer resolution 4 cm ^-1 , number of scans 16 times, measurement wave number area 4000 cm ^The IR spectrum was measured at ⁻¹ to 400 cm ⁻¹ . The obtained IR spectrum is shown in FIG. 1 (A).
The ratio of the surface of the obtained mica-containing layer from the absorbance _{I P} of peaks present in the range of absorbance _{I E} and ^{1500cm -1} ~ ^1520cm -1 peaks present in the range of ^{1230 cm} -1 ~ 1250 cm ^-1 in the IR spectrum ( I _E / I _P ) was obtained. This value was defined as _{I 1.}
Also, D. E. N. A mixture of 143 parts by weight of 438 and 1 part by weight of dimethyl-p-acetoxyphenylsulfonium = hexafluoroantimonate as a curing agent is adhered on the ATR prism, the ratio (I _E / I _P ) for the mixture (reference sample) being It calculated | required by the same method. This value was defined as _{I 0.}
The resulting I ₀ and I ₁ and curing of the epoxy resin at the surface of the mica-containing layer by the following equation (i) using (surface hardening degree) was calculated.

Surface hardening degree (%) = [1- (I ₁ / I ₀ )] × 100 (i)

(2) DSC measurement Measure 10 mg of prepreg mica tape in an open aluminum sample pan, and use a DSC measurement device (PerkinElmer, DSC 8000, temperature increase rate 10 ° C / min, measurement temperature range 30 ° C to 300 ° C under nitrogen atmosphere) It was measured. The area value in the range of 90 ° C. to 290 ° C. was calculated with analysis software (Pyris Data Analysis), and the calorific value (mJ / mg) of the epoxy resin contained in the prepreg mica tape was calculated. This value was defined as _{A 1.} Also, D. E. N. With a mixture of 143 parts by mass of 438 and 1 part by mass of dimethyl-p-acetoxyphenylsulfonium = hexafluoroantimonate as a curing agent, the calorific value of the epoxy resin was calculated by the same method. This value was defined as _{A 0.}
The curing degree (total curing degree) of the epoxy resin for the entire prepreg mica tape was calculated from the formula (ii) using A ₁ and A ₀ .
Overall degree of curing _{(%) = [1- (A} 1 / A 0)] × 100 (ii)

(3) Measurement of content rate of volatile component A prepreg mica tape was cut out to 30 mm × 30 mm, weighed in a state of being put in an aluminum cup, and the weight of the prepreg mica tape before heating was measured. After heating at 150 ° C. for 10 minutes, the weight of the prepreg mica tape was measured, and the content (VC) of the volatile component (mass%) was measured from the formula (iii).
VC (mass%) = [1- (S ₁ / S ₀ )] × 100 (iii)
S ₀ : Weight of prepreg mica tape before heating S ₁ : Weight of prepreg mica tape after heating

(4) Flexibility Measurement The flexibility of the prepreg mica tape was measured in accordance with JIS C2116: 2011. The smaller the measurement value, the better the flexibility. Specifically, the flexibility of five test pieces each having a width of 30 mm and a length of 50 mm was measured for each example to obtain an arithmetic average value.

(5) Measurement of gel time 20 layers of prepreg mica tape were stacked and heat press was performed at 60 ° C. for 30 minutes, and after heat press, the resin component exuded from the prepreg mica tape was recovered.
The gel time of the recovered resin component was measured using a rheometer (Anton Pearl, MCR 301, frequency 1 Hz, swing angle 1%, temperature 120 ° C.).
The point at which the storage elastic modulus value exceeded the loss elastic modulus value was defined as the gelation point for 0 minutes when the retention at 120 ° C. was started, and the time until gelation was defined as the gel time (minute).

(6) Glass transition temperature (Tg) measurement The glass transition temperature of the cured product of prepreg mica tape was measured using a viscoelastic device (TA Instrumental, RSAG2, frequency 10 Hz, heating rate 5 ° C./min), and tan δ The peak top temperature was taken as the glass transition temperature.

(7) Adhesiveness of surface (insertion of separator)
Two pieces of prepreg mica tape are cut out in a size of 30 mm × 100 mm, and the load is 5 kN / m ² so that the mica containing layer of the first prepreg mica tape and the backing layer of the second prepreg mica tape are in contact with each other. It piled up. Next, the two prepreg mica tapes were pulled apart. At this time, it was visually evaluated whether the surface of the mica-containing layer and the surface of the backing layer were adhered. When the surface was not adhered, it was judged that the prepreg mica tape could be wound up without inserting the separator. When the surface was adhered, it was judged that the insertion of the separator was necessary when winding up the prepreg mica tape.

Example 2
A glass cloth (Sotayo Co., Ltd., "WEA 03G 103") was stacked on mica paper, and after applying a resin varnish, it was dried at 145 ° C. for 20 minutes to remove the solvent. The preparation conditions other than the drying temperature were the same as in Example 1. The evaluation results are shown in Table 1.

Example 3
On a mica paper, a glass cloth (Soteyo Co., Ltd., "WEA 03G 103") was stacked, and after applying a resin varnish, it was dried at 100 ° C for 20 minutes to remove the solvent. The preparation conditions other than the drying temperature were the same as in Example 1. The evaluation results are shown in Table 1.

Comparative Example 1
On a mica paper, a glass cloth (Soteyo Co., Ltd., "WEA 03G 103") was stacked, and after applying a resin varnish, it was dried at 80 ° C for 20 minutes to remove the solvent. The preparation conditions other than the drying temperature were the same as in Example 1. The evaluation results are shown in Table 1. The obtained IR spectrum is shown in FIG. 1 (B).

As apparent from Table 1, in the prepreg mica tapes of Examples 1 and 2, it was possible to wind without using a separator. On the other hand, in the prepreg mica tape of Example 3, the film could not be wound without using the separator, but no adhesion of the resin component was observed on the separator. Moreover, the flexibility of the prepreg mica tape which can be taped is 120 N / m or less, and in the example, the necessary flexibility at the time of winding was secured. On the other hand, the prepreg mica tape of the comparative example could not be wound without using a separator. Furthermore, adhesion of the resin component was seen on the separator.

All documents, patent applications, and technical standards described herein are as specific and distinct as when individual documents, patent applications, and technical standards are incorporated by reference. Incorporated herein by reference.

Claims (11)

1. A mica-containing layer comprising a thermosetting resin, a curing agent and mica, and a backing layer comprising a thermosetting resin, a curing agent and a backing material provided on one side of the mica-containing layer ,
   The prepreg mica tape in which at least one of the surface of the mica containing layer and the surface of the backing layer is cured more than the inner side in the thickness direction of the mica containing layer and the backing layer.
2. A mica-containing layer comprising a thermosetting resin, a curing agent and mica, and a backing layer comprising a thermosetting resin, a curing agent and a backing material provided on one side of the mica-containing layer ,
   A prepreg mica tape in which the degree of cure of the thermosetting resin on at least one of the surface of the mica-containing layer and the surface of the backing layer is 30% to 80%.
3. A mica-containing layer comprising an epoxy resin, a curing agent and mica, and a backing layer comprising an epoxy resin provided on one side of the mica-containing layer, a curing agent and a backing material,
   At least one of the surfaces of the mica-containing layer and the surface of the backing layer, the 1230 cm -1 ^~ 1250 cm peaks present in the range of ^-1 absorbance I _E and the epoxy resin derived from an epoxy group contained in the epoxy resin the ratio between the absorbance _{I P} of peaks present in the range of ^{1500 cm} -1 ~ 1520 cm ^-1 derived from an aromatic ring _(I E / _{I P)} contained, the ratio of the mixture of the epoxy resin and the curing agent (I _E / _{I P)} the difference between (a ratio of mixture _(I E / I _P) - the ratio of the surface _(I E _/ I P)) is, prepreg mica tape is 0.4 to 1.7.
4. The prepreg mica tape according to any one of claims 1 to 3, wherein the flexibility measured in accordance with JIS C2116: 2011 is 200 N / m or less.
5. The prepreg mica tape according to any one of claims 1 to 4, wherein the backing layer further comprises an inorganic filler.
6. The prepreg mica tape according to claim 5, wherein the inorganic filler contains boron nitride.
7. The prepreg mica tape according to any one of claims 1 to 6, wherein the curing agent contains a cationic species represented by the following general formula (I).
   

   

   
   (In the general formula (I), R ¹ and R ² each independently represent an alkyl group, a phenyl group, a benzyl group, a naphthyl group or a naphthylmethyl group. R ³ independently represents an alkyl group, a hydroxy group, Carboxy group, alkoxy group, aryloxy group, alkylcarbonyl group, arylcarbonyl group, aralkylcarbonyl group, aralkylcarbonyl group, alkoxycarbonyl group, aryloxycarbonyl group, aralkyloxycarbonyl group, alkylcarbonyloxy group, arylcarbonyloxy group, aralkylcarbonyloxy group , Alkoxycarbonyloxy group, aryloxycarbonyloxy group, aralkyloxycarbonyloxy group, arylthiocarbonyl group, arylthio group, alkylthio group, aryl group, heterocyclic hydrocarbon group, alkylsulfinyl group And arylsulfinyl group, alkylsulfonyl group, arylsulfonyl group, alkylsulfonyloxy group, arylsulfonyloxy group, hydroxy (poly) alkyleneoxy group, amino group, cyano group, nitro group or halogen atom, n is 0 to 5 Indicates an integer.)
8. The prepreg mica tape according to any one of claims 1 to 7, which is wound in a roll so that the surface of the mica-containing layer is in contact with the surface of the backing layer.
9. It further has a separator provided on at least one surface of the surface of the mica-containing layer and the surface of the backing layer, and the surface of the mica-containing layer and the surface of the backing layer are in contact via the separator. The prepreg mica tape according to any one of claims 1 to 7, which is wound in a roll.
10. A coil conductor, and an insulating layer including a cured product of the laminate of prepreg mica tapes according to any one of claims 1 to 9, and arranged to cover at least a part of the outer periphery of the coil conductor. A coil for a rotating electrical machine having a.
11. A process of forming a laminate of a prepreg mica tape according to any one of claims 1 to 9, which covers at least a part of the outer periphery of the coil conductor.
    Curing the laminate of the prepreg mica tape to form an insulating layer;
    The manufacturing method of the coil for rotary electric machines which has.

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