JPWO2018096603A1 - Coil for rotating electrical machine, method for manufacturing coil for rotating electrical machine, mica tape, cured product of mica tape, and article with insulating layer - Google Patents

Abstract

A first epoxy compound having a coil conductor and an insulating layer disposed on an outer periphery of the coil conductor, the insulating layer including mica and a cured resin component, wherein the resin component has one mesogenic structure; And a second epoxy compound having two or more mesogenic structures having the same structure as the mesogenic structure, and the proportion of the first epoxy compound obtained by liquid chromatography is Coil for rotating electrical machines that is 70% or less.

Description

  The present invention relates to a coil for a rotating electrical machine, a method for manufacturing the coil for a rotating electrical machine, a mica tape, a cured product of the mica tape, and an article with an insulating layer.

  A coil (hereinafter also simply referred to as a coil) used in a rotating electrical machine such as a generator or an electric motor generally has a coil conductor and an insulating layer disposed on the outer periphery of the coil conductor to insulate the coil conductor from the external environment. is doing. As a material for forming the insulating layer, an insulating material containing mica called a mica tape is known.

  The main purpose of the insulating layer formed using mica tape is to electrically insulate the coil from the outside, but the generator adopts an indirect cooling method in which hydrogen gas or air is cooled outside the coil. In these fields, it is desired to increase the thermal conductivity of the insulating layer. As a technique for increasing the thermal conductivity of an insulating layer formed using a mica tape, a technique for adding an inorganic filler to the mica tape is known.

  For example, Patent Document 1 describes a mica tape that can form an insulating layer having excellent thermal conductivity by containing alumina having high thermal conductivity as an inorganic filler.

JP 2005-199562 A

  In the mica tape containing the inorganic filler, in the process of forming the insulating layer, a part of the inorganic filler may flow out of the mica tape and the inorganic filler may be wasted. Therefore, development of a technique for improving the thermal conductivity of the insulating layer is awaited in addition to the method of incorporating an inorganic filler into the mica tape.

As a method for improving the thermal conductivity of the insulating layer in addition to including an inorganic filler in the mica tape, it is conceivable to use a resin component having a high thermal conductivity in a cured state as a resin component contained in the mica tape. For example, an epoxy compound having a mesogenic structure in the molecule tends to have a higher thermal conductivity in a cured state than other epoxy compounds, and therefore it can be considered to be used as a resin component of mica tape.
However, an epoxy compound having a mesogenic structure generally has high crystallinity and a high melt viscosity, so that the mica layer and the backing layer may not be sufficiently impregnated when the mica tape is produced. Further, the resin component is recrystallized after the manufacture of the mica tape, and the tape becomes hard, which may affect the quality.
As described above, there is room for improvement in the characteristics of applying an epoxy resin having a mesogenic structure as a resin component of a mica tape.

  This invention makes it a subject to provide the coil for rotary electric machines which has the insulating layer excellent in thermal conductivity, and its manufacturing method in view of the said situation. 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 article with an insulating layer 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, the insulating layer including mica and a cured product of a resin component;
The resin component includes an epoxy resin including a first epoxy compound having one mesogen structure and a second epoxy compound having two or more mesogen structures having the same structure as the mesogen structure,
The coil for rotating electrical machines, wherein the ratio of the first epoxy compound obtained by liquid chromatography is 70% or less of the entire epoxy resin.

<2> The coil for rotating electrical machines according to <1>, wherein a smectic structure is formed in the cured product of the resin component.

<3> a step of disposing a mica tape containing mica and a resin component on the outer periphery of the coil conductor, and a step of forming an insulating layer from the mica tape disposed on the outer periphery of the coil conductor.
The resin component includes an epoxy resin including a first epoxy compound having one mesogen structure and a second epoxy compound having two or more mesogen structures having the same structure as the mesogen structure,
The manufacturing method of the coil for rotary electric machines whose ratio of said 1st epoxy compound obtained by liquid chromatography is 70% or less of the said whole epoxy resin.

<4> A mica layer containing mica and a backing layer containing a backing material, and including a resin component,
The resin component includes an epoxy resin including a first epoxy compound having one mesogen structure and a second epoxy compound having two or more mesogen structures having the same structure as the mesogen structure,
A mica tape in which the proportion of the first epoxy compound obtained by liquid chromatography is 70% or less of the total epoxy resin.

<5> The mica tape according to <4>, wherein the first epoxy compound includes an epoxy compound represented by the following general formula (M).

[In General Formula (M), R < ¹ > -R < ⁴ > shows a hydrogen atom or a C1-C3 alkyl group each independently. ]

<6> The mica tape according to <4> or <5>, wherein the second epoxy compound includes an epoxy compound having two or more structures represented by the following general formula (I).

[In General Formula (I), R < ¹ > -R < ⁴ > shows a hydrogen atom or a C1-C3 alkyl group each independently. ]

<7> The mica tape according to <6>, wherein the second epoxy compound includes an epoxy compound having two structures represented by the general formula (I).

<8> The second epoxy compound includes an epoxy compound having at least one selected from the group consisting of structures represented by the following general formulas (II-A) to (II-D): <4> The mica tape according to any one of to <7>.

[In General Formulas (II-A) to (II-D), R ^{1 to} R ⁴ each independently represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and R ⁵ and R ⁶ each independently represent An alkyl group having 1 to 8 carbon atoms is shown. n and m each independently represents an integer of 0 to 4. Each X independently represents —O— or —NH—. ]

<9> The mica tape according to any one of <4> to <8>, wherein the resin component exhibits a smectic structure in a cured state.

<10> The cured product of mica tape according to any one of <4> to <9>, obtained by curing the resin component.

<11> An article with an insulating layer having an insulator and an insulating layer that is a cured product of the mica tape according to <10>, which is disposed on at least a part of the surface of the insulator.

<12> A coil for a rotating electrical machine having a coil conductor and an insulating layer disposed on an outer periphery of the coil conductor, wherein the insulating layer is a cured product of the mica tape according to <10>.

<13> The step of arranging the mica tape according to any one of <4> to <9> on the outer periphery of the coil conductor, and the step of forming an insulating layer from the mica tape arranged on the outer periphery of the coil conductor And a method for manufacturing a coil for a rotating electrical machine.

  ADVANTAGE OF THE INVENTION According to this invention, the coil for rotary electric machines which has an insulating layer excellent in heat conductivity, and its manufacturing method 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 the articles | goods with an insulating layer using the same are provided.

  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, the numerical ranges 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 “stack” indicates that the layers are stacked, and two or more layers may be bonded, or two or more layers may be detachable.
In the present specification, the “epoxy compound” means a compound having an epoxy group in the molecule. “Epoxy resin” is a concept that captures a plurality of epoxy compounds as an aggregate. The “resin component” is a concept including an epoxy resin and a component used as a curing agent as necessary.

<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, and the insulating layer includes mica and a cured product of a resin component,
The resin component includes an epoxy resin including a first epoxy compound having one mesogen structure and a second epoxy compound having two or more mesogen structures having the same structure as the mesogen structure,
The ratio of the first epoxy compound obtained by liquid chromatography is 70% or less of the entire epoxy resin.

  In the coil for rotating electrical machines of the present embodiment, the insulating layer includes a cured product of a resin component including an epoxy compound having a mesogen skeleton. This insulating layer is more excellent in thermal conductivity than a conventional insulating layer formed using a resin component containing an epoxy compound having no mesogen skeleton.

  From the viewpoint of thermal conductivity of the insulating layer, it is preferable that a smectic structure is formed in the cured resin component contained in the insulating layer. Details of the smectic structure will be described later.

  The insulating layer of the coil for rotating electrical machines of the present embodiment is formed using, for example, the mica tape of the present embodiment described later. The material, shape, size, and the like of the coil conductor used for the coil of this 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 method for manufacturing a coil for a rotating electrical machine according to the present embodiment includes a step of placing a mica tape containing mica and a resin component on the outer periphery of a coil conductor, and forming an insulating layer from the mica tape arranged on the outer periphery of the coil conductor. And a step of
The resin component includes an epoxy resin including a first epoxy compound having one mesogen structure and a second epoxy compound having two or more mesogen structures having the same structure as the mesogen structure,
The ratio of the first epoxy compound obtained by liquid chromatography is 70% or less of the entire epoxy resin.

As the mica tape used in the method for manufacturing a coil for a rotating electrical machine of the present embodiment, for example, the mica tape of the present embodiment described later can be used.
The method for disposing the mica tape on the outer periphery of the coil conductor is not particularly limited, and a commonly performed method can be adopted. For example, there is a method in which a mica tape is spirally wound around the outer periphery of a coil conductor so that a part of the mica tape overlaps. In this case, the thickness of the insulating layer obtained can be adjusted by the number of times the mica tape is wound.

  The method for forming the insulating layer from the mica tape disposed on the outer periphery of the coil conductor is not particularly limited. For example, the mica tape placed on the outer periphery of the coil conductor is heated while being pressed (heat press), and the resin component contained in the mica tape is allowed to flow out of the mica tape so as to fill the space between the overlapping mica tapes. And a method of curing this to form an insulating layer.

<Mica tape>
The mica tape of the present embodiment has a mica layer containing mica and a backing layer containing a backing material, and contains a resin component,
The resin component includes an epoxy resin including a first epoxy compound having one mesogen structure and a second epoxy compound having two or more mesogen structures having the same structure as the mesogen structure,
The ratio of the first epoxy compound obtained by liquid chromatography is 70% or less of the entire epoxy resin.

  A resin component containing an epoxy compound having a mesogenic structure tends to have a higher thermal conductivity in a cured state than a resin component containing an epoxy compound not having a mesogenic structure. For this reason, the insulating layer excellent in thermal conductivity can be formed by using the mica tape of this embodiment.

  For example, the mica tape of the present embodiment cures the resin component contained in the mica tape in a state where the mica tape is disposed on an insulator such as a coil conductor (an object on which an insulating layer is formed on the outer periphery). It is used as a band-like object (also referred to as a prepreg mica tape, an RR (Resin Rich) tape, or the like) used for forming an insulating layer on the outer periphery of an insulator.

  The resin component is present (impregnated) in the mica tape so as to fill at least a part of voids inside the mica layer and the backing layer (portions where the mica and the backing material do not exist). The resin component may further exist outside the mica layer and the backing layer.

(Resin component)
The resin component includes an epoxy resin including a first epoxy compound having one mesogen structure and a second epoxy compound having two or more mesogen structures having the same structure as the mesogen structure. Moreover, the ratio of the 1st epoxy compound obtained by a liquid chromatography is 70% or less of the whole epoxy resin.

  When the ratio of the first epoxy compound obtained by liquid chromatography is 70% or less based on the study by the present inventors, the mica layer and the backing layer of the resin component during the production of the mica tape are used. It was found that the impregnation property of was improved. The reason is not clear, but if the ratio of the first epoxy compound is 70% or less of the entire epoxy resin, the viscosity of the resin during coating decreases, and the resin easily enters the gap between the mica layer and the backing layer. Presumed to be. Moreover, it turned out that the recrystallization of the epoxy resin after mica tape manufacture is suppressed. The reason is not clear, but when the proportion of the first epoxy compound is 70% or less of the whole epoxy resin, the proportion of the epoxy resin is larger than the case where the proportion of the first epoxy compound exceeds 70% of the whole epoxy resin. This is presumably because the precipitation of crystals at a temperature below the melting temperature is suppressed.

In this embodiment, the ratio of the first epoxy compound obtained by liquid chromatography is derived from the first epoxy compound in the total area of peaks derived from all epoxy compounds in the chart obtained by liquid chromatography. It is the ratio (%) of the area of the peak. Specifically, the absorbance at a wavelength of 280 nm of the epoxy resin to be measured is detected, and is calculated from the total area of all detected peaks and the area of the peak corresponding to the first epoxy compound by the following formula. .
Percentage of area of peak derived from first epoxy compound (%) = (Area of peak derived from first epoxy compound / Total area of peaks derived from all epoxy compounds) × 100

  Liquid chromatography is performed at a sample concentration of 0.5% by mass, tetrahydrofuran as the mobile phase, and a flow rate of 1.0 ml / min. The measurement can be performed using, for example, a high performance liquid chromatograph “L6000” manufactured by Hitachi, Ltd. and a data analysis device “C-R4A” manufactured by Shimadzu Corporation. As the column, for example, “G2000HXL” and “G3000HXL” which are GPC columns manufactured by Tosoh Corporation can be used.

  From the viewpoint of improving the impregnation property, the ratio of the first epoxy compound obtained by liquid chromatography is preferably 60% or less, more preferably 50% or less of the entire epoxy resin.

  From the viewpoint of heat resistance, the proportion of the first epoxy compound obtained by liquid chromatography is preferably 20% or more, more preferably 30% or more of the entire epoxy resin.

  The epoxy resin may contain other epoxy compounds other than the first epoxy compound and the second epoxy compound. However, the ratio obtained by liquid chromatography of other epoxy compounds is preferably 10% or less of the entire epoxy resin.

The resin component may include only an epoxy compound having a mesogenic structure, or may further include an epoxy compound that does not correspond to an epoxy compound having a mesogenic structure.
From the viewpoint of increasing the thermal conductivity of the insulating layer, the proportion of the epoxy compound having a mesogenic structure in the entire epoxy compound (epoxy resin) is preferably 50% by mass or more, and more preferably 70% by mass or more. More preferably, it is 90% by mass or more.

  The epoxy compound having a mesogenic structure may be one type or two or more types. Examples of the mesogenic structure of the epoxy compound include, for example, a biphenyl structure, a phenylbenzoate structure, an azobenzene structure, a stilbene structure, a terphenyl structure, an anthracene structure, a derivative thereof, and two or more of these mesogenic structures via a bonding group. Examples include bonded structures.

  From the viewpoint of increasing the thermal conductivity of the insulating layer, the epoxy compound having a mesogenic structure preferably exhibits a higher order structure in a cured state. Here, the higher order structure means a structure including a higher order structure in which constituent elements are arranged to form a micro ordered structure, and corresponds to, for example, a crystal phase and a liquid crystal phase. The presence or absence of such a higher order structure can be determined by a polarizing microscope. That is, in the observation in the crossed Nicols state, it can be distinguished by seeing interference fringes due to depolarization. This higher order structure usually exists in an island shape in the cured product to form a domain structure, and one of the islands corresponds to one higher order structure. In general, the constituent elements of this higher order structure are formed by covalent bonds.

  Examples of the higher order structure formed in the cured state include a nematic structure and a smectic structure. Each of the nematic structure and the smectic structure is a kind of liquid crystal structure. The nematic structure is a liquid crystal structure in which the molecular long axis is oriented in a uniform direction and has only an alignment order. On the other hand, the smectic structure is a liquid crystal structure having a one-dimensional positional order in addition to the orientation order and having a layer structure. The order is higher in the smectic structure than in the nematic structure.

From the viewpoint of increasing the thermal conductivity of the insulating layer, the epoxy compound having a mesogenic structure is more preferably a smectic structure in a cured state.
Whether or not a smectic structure is formed in a cured state can be determined by X-ray diffraction measurement of the cured product. Using CuKα1 wire, tube voltage 40 kV, tube current 20 mA, 2θ = 0.5 to 30 °, and if it is a cured product having a smectic structure, it is diffracted to 2θ = 2 to 10 °. A peak appears. X-ray diffraction measurement can be performed, for example, using an X-ray diffraction apparatus manufactured by Rigaku Corporation.

(First epoxy compound)
The first epoxy compound is not particularly limited as long as it is an epoxy compound having one mesogen structure. Examples of the mesogenic structure include a biphenyl structure, a phenylbenzoate structure, an azobenzene structure, a stilbene structure, a terphenyl structure, an anthracene structure, derivatives thereof, and a structure in which two or more of these mesogenic structures are bonded via a bonding group. Can be mentioned. The first epoxy compound contained in the epoxy resin may be one kind or two or more kinds having different molecular structures.
In the present specification, an epoxy compound having “one mesogenic structure” means that two or more mesogenic structures having the same structure (for example, two or more biphenyl structures) are not present in the molecule of the epoxy compound. .

  The molecular weight of the first epoxy compound is not particularly limited. In the case of synthesizing the second epoxy compound using the first epoxy compound using a solvent, from the viewpoint of ease of synthesis such as solubility in various solvents, it is preferably 800 or less, and 600 or less. More preferably. From the viewpoint of forming a higher order structure in the cured product, it is preferably 300 or more, and more preferably 350 or more.

  Preferable examples of the first epoxy compound include compounds represented by the following general formula (M). The resin component containing the compound represented by the general formula (M) forms a smectic liquid crystal structure in the cured product. When the first epoxy compound is a compound represented by the general formula (M), the compound represented by the general formula (M) may be one kind or two or more kinds.

In general formula (M), R < ¹ > -R < ⁴ > shows a hydrogen atom or a C1-C3 alkyl group each independently. R ^{1 to} R ⁴ are each independently preferably a hydrogen atom or an alkyl group having 1 to 2 carbon atoms, more preferably a hydrogen atom or a methyl group, and even more preferably a hydrogen atom. Further, it is preferable that two to four of R ¹ to R ⁴ is a hydrogen atom, more preferably 3 or 4 hydrogen atoms, further that all four are hydrogen atoms preferable. If any of R ¹ to R ⁴ is an alkyl group having 1 to 3 carbon atoms, it is preferred that at least one of ^{R 1} and ^{R 4} is an alkyl group having 1 to 3 carbon atoms.

  Examples of the compound represented by the general formula (M) include compounds described in JP2011-74366A. Specifically, 4- {4- (2,3-epoxypropoxy) phenyl} cyclohexyl = 4- (2,3-epoxypropoxy) benzoate and 4- {4- (2,3-epoxypropoxy) phenyl} cyclohexyl = At least one compound selected from the group consisting of 4- (2,3-epoxypropoxy) -3-methylbenzoate.

(Second epoxy compound)
The second epoxy compound is not particularly limited as long as it is an epoxy compound having two or more mesogenic structures having the same structure as the mesogenic structure of the first epoxy compound.
When the epoxy resin contains the second epoxy compound in addition to the first epoxy compound, the viscosity below the melting point of the epoxy compound tends to be lower than when the epoxy resin contains only the first epoxy compound. is there.

  Even if the second epoxy compound is obtained by a reaction between the first epoxy compound and a compound having a functional group capable of reacting with the epoxy group of the first epoxy compound, Even those obtained by self-polymerization may be obtained by other methods.

  The number of mesogenic structures having the same structure as the mesogenic structure of the first epoxy compound contained in the second epoxy compound is not particularly limited. From the viewpoint of the intrinsic viscosity (melt viscosity), it is preferable that the number of mesogenic structures of the second epoxy compound that has the largest proportion obtained by liquid chromatography is 2.

  When the second epoxy compound is obtained by a reaction between the first epoxy compound and a compound having a functional group capable of reacting with the epoxy group of the first epoxy compound, as the second epoxy compound, The epoxy compound which has a structure represented by the following general formula (A) or (B) is mentioned.

In the general formulas (A) and (B), * represents a bonding position with an adjacent atom. Adjacent atoms include oxygen and nitrogen atoms. R ^{1 to} R ³ each independently represents an alkyl group having 1 to 8 carbon atoms. n, m and l each independently represents an integer of 0 to 4. n, m and l are each independently preferably an integer of 0 to 2, more preferably an integer of 0 to 1, and still more preferably 0.

  Among the structures represented by the general formula (A) or (B), a structure represented by the following general formula (a) or (b) is preferable. An epoxy compound having such a structure tends to have a linear molecular structure. For this reason, it is considered that the stacking property of molecules is high and higher-order structures are more easily formed.

^* In the general formula (a) and (b), defined and preferred examples of ^R 1 ~R 3, n, m and l are ^* in formula (A) and ^{(B), R 1 ~R 3} , n, The definition and preferred examples of m and l are the same.

  When the second epoxy compound is an epoxy compound having a structure represented by the general formula (A) or (B), the second epoxy compound is represented by the following general formula (C) or (D). Epoxy compounds.

Definitions and preferred examples of ^R 1 ^{to R} 3, n, m and l in formula (C) and (D) has the general formula (A) and in ^R 1 ^{to R} 3, n, m and l (B) Definitions and preferred examples are the same. Ms independently represents a divalent group having a mesogenic structure. Each X independently represents —O— or —NH—.

  The second epoxy compound may be an epoxy compound having two or more structures represented by the following general formula (I).

Specific examples of ^R 1 to R ⁴ in General Formula (I) are the same as the specific examples of ^R 1 to R ⁴ in the general formula (M), is the same preferred ranges thereof. ]

  The second epoxy compound may be an epoxy compound having at least one selected from the group consisting of structures represented by the following general formulas (II-A) to (II-D).

In general formulas (II-A) to (II-D), R ^{1 to} R ⁴ each independently represent a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and R ⁵ and R ⁶ each independently represent carbon. The alkyl group of number 1-8 is shown. n and m each independently represent an integer of 0 to 4. Each X independently represents —O— or —NH—.

Specific examples of R ^{1 to} R ⁴ in General Formulas (II-A) to (II-D) are the same as the specific examples of R ^{1 to} R ⁴ in General Formula (M), and preferred ranges thereof are also the same. .

In general formulas (II-A) to (II-D), R ⁵ and R ⁶ each independently represent an alkyl group having 1 to 8 carbon atoms, preferably an alkyl group having 1 to 3 carbon atoms, More preferably, it is a group.

In general formulas (II-A) to (II-D), n and m each independently represent an integer of 0 to 4, preferably an integer of 0 to 2, and an integer of 0 to 1. Is more preferred and 0 is even more preferred. That is, in the general formulas (II-A) to (II-D), the benzene ring to which R ⁵ or R ⁶ is attached preferably has 2 to 4 hydrogen atoms, and preferably 3 or 4 hydrogen atoms. More preferably, it has an atom, and further preferably has 4 hydrogen atoms.

  From the viewpoint of higher order structure formation, it has a structure represented by the following general formulas (II-a) to (II-d) among the structures represented by the general formulas (II-A) to (II-D). Epoxy compounds are preferred.

Formula ^{(II-a) ~ R 1} ~R 6 in (II-d), n, definition and preferred examples of m and X have the general formula (II-A) ^R 1 in the ~ (II-D) ~R ⁶ , N, m and X are the same as defined and preferred examples.

  Examples where the second epoxy compound is an epoxy compound (dimer) having two structures represented by the general formula (I) include the following general formulas (III-A) to (III to F): And at least one selected from the group consisting of epoxy compounds represented by the formula:

^R 1 ^{to R} 6 in the general formula (III-A) ~ (III~F ), n, the definition of m and X have the general formula ^{(II-A) R 1 ~R} 6 in ~ (II-D), n , M and X are the same, and the preferred range is also the same.

  From the viewpoint of higher order structure formation, epoxy compounds represented by the following general formulas (III-a) to (III to f) among the epoxy compounds represented by the general formulas (III-A) to (III to F) Is preferred.

Formula (III-a) ^R 1 in the ^{~ (III~f) ~R 6, n} , the definition of m and X, ^R 1 ^{to R} 6 in the general formula (III-A) ~ (III -F), n , M and X are the same, and the preferred range is also the same.

The method for synthesizing the second epoxy compound by reacting the first epoxy compound with a compound having a functional group capable of reacting with the epoxy group of the first epoxy compound is not particularly limited. Specifically, for example, a first epoxy compound, a compound having a functional group capable of reacting with the epoxy group of the first epoxy compound, and a reaction catalyst used as necessary are dissolved in a solvent and heated. The second epoxy compound can be synthesized by stirring while stirring.
Alternatively, for example, the first epoxy compound and the compound having a functional group capable of reacting with the epoxy group of the first epoxy compound are mixed without using a reaction catalyst and a solvent as necessary, and stirred while heating. By doing so, the second epoxy compound can be synthesized.

  The solvent is a solvent that can dissolve the first epoxy compound and the compound having a functional group capable of reacting with the epoxy group of the first epoxy compound and can be heated to a temperature necessary for the reaction of both compounds. If there is, there is no particular limitation. Specific examples include cyclohexanone, cyclopentanone, ethyl lactate, propylene glycol monomethyl ether, N-methylpyrrolidone, methyl cellosolve, ethyl cellosolve, propylene glycol monopropyl ether.

  Especially if the quantity of a solvent is the quantity which can melt | dissolve the 1st epoxy compound, the compound which has a functional group which can react with the epoxy group of a 1st epoxy compound, and the reaction catalyst used as needed in reaction temperature. Not limited. Although the solubility differs depending on the type of raw material before reaction, the type of solvent, etc., for example, if the charged solid content concentration is 20% by mass to 60% by mass, the viscosity of the solution after the reaction becomes a preferable range. There is a tendency.

  The compound having a functional group capable of reacting with the epoxy group of the first epoxy compound is not particularly limited. From the viewpoint of forming a smectic structure in the cured product, the compound having a functional group capable of reacting with the epoxy group of the first epoxy compound is a dihydroxybenzene compound having a structure in which two hydroxyl groups are bonded to one benzene ring, A diaminobenzene compound having a structure in which two amino groups are bonded to one benzene ring, a dihydroxybiphenyl compound having a structure in which one hydroxyl group is bonded to each of two benzene rings forming a biphenyl structure, and two forming a biphenyl structure It is preferably at least one selected from the group consisting of diaminobiphenyl compounds each having a structure in which one amino group is bonded to the benzene ring (hereinafter also referred to as a specific aromatic compound).

  By reacting the epoxy group of the first epoxy compound with the hydroxyl group or amino group of the specific aromatic compound, it is selected from the group consisting of structures represented by the general formulas (II-A) to (II-D) A second epoxy compound having at least one can be synthesized.

Examples of the dihydroxybenzene compound include 1,2-dihydroxybenzene (catechol), 1,3-dihydroxybenzene (resorcinol), 1,4-dihydroxybenzene (hydroquinone), and derivatives thereof.
Examples of the diaminobenzene compound include 1,2-diaminobenzene, 1,3-diaminobenzene, 1,4-diaminobenzene, and derivatives thereof.
Examples of the dihydroxybiphenyl compound include 3,3′-dihydroxybiphenyl, 3,4′-dihydroxybiphenyl, 4,4′-dihydroxybiphenyl, and derivatives thereof.
Examples of the diaminobiphenyl compound include 3,3′-diaminobiphenyl, 3,4′-diaminobiphenyl, 4,4′-diaminobiphenyl, and derivatives thereof.
Examples of the derivative of the specific aromatic compound include a compound in which a substituent such as an alkyl group having 1 to 8 carbon atoms is bonded to the benzene ring of the specific aromatic compound. A specific aromatic compound may be used individually by 1 type, and may use 2 or more types together.

  From the viewpoint of easy formation of a smectic structure in the cured epoxy resin, 1,4-dihydroxybenzene, 1,4-diaminobenzene, 4,4′-dihydroxybiphenyl and 4,4 are used as the specific aromatic compound. '-Diaminobiphenyl is preferred. In these compounds, since the two hydroxyl groups or amino groups on the benzene ring are in a para-position, the second epoxy compound obtained by reacting this with the first epoxy compound tends to have a linear structure. . For this reason, it is considered that the stacking property of the molecule is high and it is easy to form a smectic structure in the cured product.

  The type of the reaction catalyst is not particularly limited, and an appropriate catalyst can be selected from the viewpoint of reaction rate, reaction temperature, storage stability, and the like. Specific examples include imidazole compounds, organophosphorus compounds, tertiary amines, and quaternary ammonium salts. A reaction catalyst may be used individually by 1 type, and may use 2 or more types together.

From the viewpoint of the heat resistance of the cured product, an organic phosphorus compound is preferable as the reaction catalyst.
Preferred examples of the organic phosphorus compound include an organic phosphine compound, a compound having an intramolecular polarization formed by adding a compound having a π bond such as maleic anhydride, a quinone compound, diazophenylmethane, and a phenol resin to an organic phosphine compound, organic And a complex of a phosphine compound and an organic boron compound.

  Specific examples of the organic phosphine compound include triphenylphosphine, diphenyl (p-tolyl) phosphine, tris (alkylphenyl) phosphine, tris (alkoxyphenyl) phosphine, tris (alkylalkoxyphenyl) phosphine, tris (dialkylphenyl) phosphine, Tris (trialkylphenyl) phosphine, tris (tetraalkylphenyl) phosphine, tris (dialkoxyphenyl) phosphine, tris (trialkoxyphenyl) phosphine, tris (tetraalkoxyphenyl) phosphine, trialkylphosphine, dialkylarylphosphine, alkyldiaryl A phosphine etc. are mentioned.

  Specific examples of the quinone compound include 1,4-benzoquinone, 2,5-toluquinone, 1,4-naphthoquinone, 2,3-dimethylbenzoquinone, 2,6-dimethylbenzoquinone, 2,3-dimethoxy-5-methyl- Examples include 1,4-benzoquinone, 2,3-dimethoxy-1,4-benzoquinone, and phenyl-1,4-benzoquinone.

  Specific examples of the organic boron compound include tetraphenyl borate, tetra-p-tolyl borate, and tetra-n-butyl borate.

  The amount of the reaction catalyst is not particularly limited. From the viewpoint of reaction rate and storage stability, 0.1 part by mass with respect to 100 parts by mass of the total of the first epoxy compound and the compound having a functional group capable of reacting with the epoxy group of the first epoxy compound. It is preferable that it is -1.5 mass part, and it is more preferable that it is 0.2 mass part-1 mass part.

  When synthesizing the second epoxy compound using the first epoxy compound, even if all of the first epoxy is reacted to be in the state of the second epoxy compound, a part of the first epoxy compound is You may remain | survive in the state of a 1st epoxy compound, without reacting.

The synthesis of the second epoxy compound can be performed using a reaction vessel such as a flask for a small scale and a synthesis kettle for a large scale. A specific synthesis method is as follows, for example.
First, a 1st epoxy compound is thrown into reaction container, a solvent is put as needed, and it heats to reaction temperature with an oil bath or a heat medium, and melt | dissolves a 1st epoxy compound. The compound which has a functional group which can react with the epoxy group of a 1st epoxy compound is thrown into there, and then a reaction catalyst is thrown in as needed, and reaction is started. Next, the second epoxy compound is obtained by distilling off the solvent under reduced pressure as necessary.

  The reaction temperature is not particularly limited as long as the reaction proceeds between the epoxy group of the first epoxy compound and the functional group capable of reacting with the epoxy group, and is preferably in the range of, for example, 100 ° C to 180 ° C. More preferably, the temperature is in the range of 100 ° C to 150 ° C. By setting the reaction temperature to 100 ° C. or higher, the time until the reaction is completed tends to be shortened. On the other hand, by setting the reaction temperature to 180 ° C. or lower, the possibility of gelation tends to be reduced.

  The mixing ratio of the first epoxy compound used for the synthesis of the second epoxy compound and the compound having a functional group capable of reacting with the epoxy group is not particularly limited. For example, even if the ratio (A: B) of the number of equivalents of epoxy groups (A) and the number of equivalents of functional groups capable of reacting with epoxy groups (B) is in the range of 100: 100 to 100: 1, Good. From the viewpoint of fracture toughness and heat resistance of the cured product, a blending ratio in which A: B is in the range of 100: 50 to 100: 1 is preferable.

  The structure of the second epoxy compound is, for example, the molecular weight of the second epoxy compound estimated to be obtained from the reaction between the first epoxy compound used for the synthesis and the compound having a functional group capable of reacting with the epoxy group. And the molecular weight of the target compound determined by liquid chromatography carried out using a liquid chromatograph equipped with UV and mass spectrum detectors.

  The epoxy equivalent of the entire epoxy compound (epoxy resin) is not particularly limited. From the viewpoint of achieving both the fluidity of the resin component and the thermal conductivity of the cured product, it is preferably 245 g / eq to 500 g / eq, more preferably 250 g / eq to 450 g / eq, and 260 g / eq to More preferably, it is 400 g / eq. When the epoxy equivalent of the epoxy resin is 245 g / eq or more, the crystallinity of the resin component does not become too high, and the fluidity tends not to decrease. On the other hand, if the epoxy equivalent of the epoxy resin is 500 g / eq or less, the crosslinking density of the epoxy resin is unlikely to decrease, and the thermal conductivity of the molded product tends to increase. In the present embodiment, the epoxy equivalent of the epoxy resin is measured by a perchloric acid titration method.

  The number average molecular weight (Mn) and the weight average molecular weight (Mw) of the epoxy resin are not particularly limited and can be selected according to desired properties of the epoxy resin. From the viewpoint of viscosity, the weight average molecular weight (Mw) of the epoxy resin is preferably selected from the range of 1200 to 1550.

In the present embodiment, the number average molecular weight (Mn) and the weight average molecular weight (Mw) of the epoxy resin are values obtained by liquid chromatography.
Liquid chromatography is performed at a sample concentration of 0.5% by mass, tetrahydrofuran as the mobile phase, and a flow rate of 1.0 ml / min. A calibration curve is prepared using a polystyrene standard sample, and Mn and Mw are measured in terms of polystyrene using the calibration curve.
The measurement can be performed using, for example, a high performance liquid chromatograph “L6000” manufactured by Hitachi, Ltd. and a data analysis device “C-R4A” manufactured by Shimadzu Corporation. As the column, for example, “G2000HXL” and “G3000HXL” which are GPC columns manufactured by Tosoh Corporation can be used.

(Mica)
The kind of mica contained in the mica layer 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 is preferable from the viewpoints of price and availability.

  The particle diameter 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 corresponds to ISO3310-1: 2000. In addition, when using ISO3310-1: 2000, it is preferable to apply what has the shape of a sieve mesh square like 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. Thereafter, while shaking the container, JIS standard sieves (JIS-Z-8801-1: 2006, ISO3310-1: 2000, Tokyo Screen Co., Ltd., test sieve) ).
The sieving is performed using an electromagnetic sieve vibrator at a frequency of 3000 times / minute, an amplitude of 1 mm, and 10 minutes.

  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, is preferably in a range of ^{80g / m 2 ~230g / m 2} , the range of 100g / ^{m 2} ~200g / m 2 is more preferable. If the amount of mica in the mica layer is 80 g / m ² or more, sufficient insulating properties tend to be secured. If the amount of the mica mica layer is 230 g / m ² or less, it can reduce the thickness of the mica tape, in sufficient tendency to thermal conductivity is ensured.

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

  The average thickness of the backing material is not particularly limited. For example, it is preferably 30 μm to 60 μm, and more preferably 45 μm to 50 μm. When the average thickness of the backing material is 30 μm or more, it is suppressed that the backing layer becomes 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 thickness of the backing material is 60 μm or less, the thickness of the mica tape can be suppressed, and the occurrence of breakage, cracks, and the like of the mica tape during the process of winding the mica tape around the insulator tends to be suppressed.

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

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

(Other ingredients)
The mica tape may contain other components other than the epoxy resin, mica and the backing material as necessary. Examples of other components include a curing catalyst, an inorganic filler, a curing agent, a coupling agent, an antioxidant, an anti-aging agent, a stabilizer, a flame retardant, and a thickener. When a mica tape contains these components, the content is not particularly limited.

  Specific examples of the curing catalyst include compounds exemplified as the reaction catalyst that can be used for the synthesis of the above-described multimer of epoxy compounds.

  Specific examples of the inorganic filler include silica, boron nitride, and alumina. Alumina is preferable from the viewpoint of thermal conductivity. Boron nitride is preferable from the viewpoint of achieving both thermal conductivity and winding ability of the mica tape.

  The kind of boron nitride is not particularly limited, and examples thereof 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.

  The average particle diameter of the inorganic filler can be measured by using, for example, a laser diffraction / scattering particle size distribution analyzer (Microtrack MT3000II, Nikkiso Co., Ltd.). 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.

  An inorganic filler may be used individually by 1 type, or may use 2 or more types together. 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.

  Specific examples of the curing agent include amine curing agents, phenol curing agents, acid anhydride curing agents, polymercaptan curing agents, polyaminoamide curing agents, isocyanate curing agents, and blocked isocyanate curing agents.

<Overall configuration of mica tape>
The average thickness of the mica tape 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.

  From the viewpoint of easy winding of the 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 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.

  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 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 60 μm or less, and more preferably 50 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 tape is the arithmetic average value of the measured values obtained by measuring the thickness of the mica tape at a total of 10 locations using a micrometer (MDC-SB, Mitutoyo Corporation). .

  In the present embodiment, the thickness of the mica layer and the backing layer in the mica tape is determined by measuring the thickness of the mica layer and the backing layer in the cross section of the mica tape with a micrometer of a stereomicroscope (for example, Olympus Corporation “BX51”). Observe 3 points and use the arithmetic average.

  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 in the mica tape may be 15% by mass to 40% by mass of the entire mica tape, and more preferably 25% by mass to 33% by mass.

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.
Resin component content = {(mass before heating−mass after heating) / mass before heating} × 100

  When the mica tape contains an inorganic filler, the content of the inorganic filler in the mica tape is not particularly limited.

  The mica tape may have a protective layer (protective film) provided on the outermost surface of the mica tape, if necessary.

<Mica tape manufacturing method>
The manufacturing method in particular of the mica tape of this embodiment is not restrict | limited, A well-known manufacturing method is applicable.

  As an example of a method for producing mica tape, a step of preparing a laminate by placing a backing material on mica paper, and a composition containing a resin component and other components contained as necessary, And a step of applying to the backing material side. The mica paper is a sheet-like object formed by gathering mica.

  Details and preferred embodiments of the mica, the backing material, the resin component and other components contained in the composition, and the produced mica tape are as described above.

  If desired, the composition may include a solvent. By including the solvent, the viscosity of the composition is lowered, and the impregnation property tends to be improved. The type of the solvent is not particularly limited, and can be selected from commonly used organic solvents. Specific examples include cyclohexanone, methyl ethyl ketone, toluene, methanol and the like. A solvent may use only 1 type or may use 2 or more types together.

  The application of the composition is preferably performed so that the composition applied to the backing material oozes out to the other surface side (mica paper 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, electrical insulation and thermal conductivity tend to be improved.

<Hardened mica tape>
The cured product of the mica tape of this embodiment is obtained by curing the resin component contained in the mica tape described above. The curing method is not particularly limited, and can be selected from ordinary methods.

<Article with insulating layer>
The article with an insulating layer according to the present embodiment includes an insulator and an insulating layer that is a cured product of the mica tape according to the present 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 the mica tape while applying pressure (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. There is a method of forming an insulating layer by filling and curing the insulating layer.

  The to-be-insulated material that can be applied to the article with an insulating layer of the present embodiment is not particularly limited, and examples thereof include a coil conductor of a coil for a rotating electrical machine described above, rod-shaped copper, and plate-shaped copper.

  By using the mica tape of this embodiment, an insulating layer having excellent thermal conductivity can be formed. Therefore, when the article with an insulating layer of the present embodiment is a coil, when cooling the coil, a hydrogen cooling method or an air cooling method is adopted even for a coil of a scale that conventionally employs a direct water cooling method. It becomes possible to simplify the structure of the coil.

  EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples.

<Example 1>
(1) Synthesis of epoxy resin In a 500 mL three-necked flask, an epoxy monomer represented by the following structure (4- {4- (2,3-epoxypropoxy) phenyl} cyclohexyl = 4- (2,3-epoxypropoxy) benzoate) 50 g (0.118 mol) was weighed, and 80 g of propylene glycol monomethyl ether was added thereto. A cooling tube and a nitrogen introducing tube were installed in the three-necked flask, and a stirring blade was attached so as to be immersed in the solvent. This three-necked flask was immersed in a 120 ° C. oil bath, and stirring was started. After confirming that the epoxy monomer dissolved and became a transparent solution, hydroquinone was added as a specific aromatic compound.
The amount of hydroquinone added was such that the ratio (A: B) of the epoxy group equivalent number (A) of the epoxy monomer to the hydroquinone hydroxyl group equivalent number (B) was 100: 13. Further, 0.5 g of triphenylphosphine was added as a reaction catalyst, and heating was continued at an oil bath temperature of 120 ° C. After continuing the heating for 5 hours, the propylene glycol monomethyl ether was distilled off under reduced pressure from the reaction solution, and the residue was cooled to room temperature (25 ° C.), thereby a part of the epoxy monomer (first epoxy compound) used for the synthesis. Obtained an epoxy resin in a state where a multimer (second epoxy compound) was formed (prepolymerized).

  About the obtained epoxy resin, when the ratio in the whole epoxy resin of an epoxy monomer was measured by the liquid chromatography on the conditions mentioned above, it was 66%.

(2) Preparation of resin composition 87.4% by mass of the obtained epoxy resin, 2.6% by mass of boron trifluoride monoethylamine (Wako Pure Chemical Industries, Ltd.) as a curing catalyst, and cyclohexanone as a solvent ( Wako Pure Chemical Industries, Ltd.) 10.0% by mass was mixed to prepare a resin composition.

(3) Production of mica tape Unfired hard mica was dispersed in water to form mica particles, and the paper was made with a paper machine to produce mica paper (unfired hard laminated mica) having a mica amount of 180 g / m ² .
When the unfired hard mica used for the preparation of mica paper was sieved using a JIS standard sieve having a nominal mesh opening of 2.8 mm, the proportion of mica that did not pass through the mesh was 0% by mass of the entire mica.
When the unfired hard mica used for the preparation of mica paper was sieved using a JIS standard sieve having a nominal aperture of 0.5 mm, the proportion of mica that did not pass through the sieve was 63% by mass of the entire mica.

  A glass cloth (Soyo Co., Ltd., “WEA 03G 103”, thickness 0.030 mm) as a backing material was stacked on the mica paper placed on the table to form a laminate. Subsequently, the resin composition heated at 90 degreeC was apply | coated to the upper surface of the glass cloth using the roll coater. The application was carried out so that the resin composition penetrates the entire mica paper under the glass cloth, and the impregnation property of the resin composition into the glass cloth and mica paper was good. Thereafter, the laminate was dried at 100 ° C. for 20 minutes to produce a laminate comprising a mica layer containing a resin component and a glass cloth layer (backing layer). The laminate was cut so that the width was 30 mm to produce a mica tape.

(4) Measurement of thermal conductivity Sixteen mica tapes produced by the above-described method are stacked and subjected to heat pressing at 170 ° C. for 1 hour to cure the resin component, thereby producing a laminated cured product for measuring thermal conductivity. did. About this laminated hardened | cured material, the heat conductivity (W / (m * K)) was measured using the heat conductivity measuring apparatus (Eihiro Seiki Co., Ltd., "HC-110"). The results are shown in Table 1.

(5) Evaluation of recrystallization After the mica tape was prepared (application of the resin composition) and left at 30 ° C. for 3 hours, a test piece having a length of 20 cm was prepared and visually observed at 30 ° C. The recrystallization of the components was evaluated according to the following evaluation criteria. The results are shown in Table 1.
The resin component is transparent and does not crack when the tape is bent ... A
The resin component is slightly transparent, and there are 1 to 4 cracks, wrinkles, etc. when the tape is bent. B
5 or more cracks and wrinkles when the tape is bent because the resin component is opaque. C

(6) Evaluation of impregnation property of resin component During the production of mica tape, the impregnation property of the laminate of the resin composition was evaluated according to the following evaluation criteria. The results are shown in Table 1.
In a 1 m ² laminate, no impregnated area is seen ... A
In a 1 m ² laminate, the area of poor impregnation is less than 0.2 m ² ... B
In a 1 m ² laminate, the area of impregnation failure is 0.2 m ² or more ... C

(7) Presence / absence of smectic structure formation A cured product was prepared using the epoxy resin synthesized by the method described above, and X-ray diffraction measurement of the cured product was performed. The measurement conditions were CuKα rays, tube voltage 40 kV, tube current 20 mA, and measurement angle 2θ = 0.5-30 °. An X-ray diffractometer manufactured by Rigaku Corporation was used as the evaluation device. The results are shown in Table 1.
Existence: A diffraction peak appears in the range of 2θ = 2 ° to 10 °, and a smectic structure is formed.
None: No diffraction peak appears in the range of 2θ = 2 ° to 10 °, and no smectic structure is formed.

<Example 2>
Example 1 except that the amount of hydroquinone added was changed so that the ratio (A: B) of the number of equivalents of epoxy groups (A) of the epoxy monomer to the number of equivalents (B) of hydroxyl groups of hydroquinone was 100: 25. Thus, an epoxy resin was synthesized. The ratio of the epoxy monomer in the whole obtained epoxy resin was 45%.

  A resin composition was prepared by mixing 97.1% by mass of the synthesized epoxy resin and 2.9% by mass of boron trifluoride monoethylamine (Wako Pure Chemical Industries, Ltd.) as a curing catalyst.

  Using the prepared resin varnish, a mica tape was produced in the same manner as in Example 1, and the thermal conductivity was measured and evaluated. Moreover, it was confirmed whether the smectic structure was formed in the hardened | cured material of an epoxy resin. The results are shown in Table 1.

<Example 3>
Example 1 except that the amount of hydroquinone added was changed so that the ratio (A: B) of the number of equivalents of epoxy groups (A) of the epoxy monomer to the number of equivalents (B) of hydroxyl groups of hydroquinone was 100: 30. Thus, an epoxy resin was synthesized. The ratio of the epoxy monomer in the whole epoxy resin obtained was 38%.

  A resin composition was prepared by mixing 97.1% by mass of the synthesized epoxy resin and 2.9% by mass of boron trifluoride monoethylamine (Wako Pure Chemical Industries, Ltd.) as a curing catalyst.

  A mica tape was produced using the prepared resin composition in the same manner as in Example 1, and the thermal conductivity was measured and evaluated. Moreover, it was confirmed whether the smectic structure was formed in the hardened | cured material of an epoxy resin. The results are shown in Table 1.

<Example 4>
Example 1 except that the amount of hydroquinone added was changed so that the ratio (A: B) of the number of equivalents of epoxy groups (A) of the epoxy monomer to the number of equivalents (B) of hydroxyl groups of hydroquinone was 100: 35. Thus, an epoxy resin was synthesized. The ratio of the epoxy monomer in the whole obtained epoxy resin was 31%.

  A resin composition was prepared by mixing 97.1% by mass of the synthesized epoxy resin and 2.9% by mass of boron trifluoride monoethylamine (Wako Pure Chemical Industries, Ltd.) as a curing catalyst.

  A mica tape was produced using the prepared resin composition in the same manner as in Example 1, and the thermal conductivity was measured and evaluated. Moreover, it was confirmed whether the smectic structure was formed in the hardened | cured material of an epoxy resin. The results are shown in Table 1.

<Example 5>
4,4-dihydroxybiphenyl is used in place of hydroquinone, and the ratio (A: B) of the number of equivalents (A) of epoxy groups of epoxy monomers to the number of equivalents (B) of hydroxyl groups of 4,4-dihydroxybiphenyl is 100: An epoxy resin was synthesized in the same manner as in Example 1 except that the addition amount of hydroquinone was changed to 30. The ratio of the epoxy monomer in the whole obtained epoxy resin was 40%.

  A resin composition was prepared by mixing 97.1% by mass of the synthesized epoxy resin and 2.9% by mass of boron trifluoride monoethylamine (Wako Pure Chemical Industries, Ltd.) as a curing catalyst.

  A mica tape was produced using the prepared resin composition in the same manner as in Example 1, and the thermal conductivity and glass transition temperature were measured. Moreover, it was confirmed whether the smectic structure was formed in the hardened | cured material of an epoxy resin. The results are shown in Table 1.

<Comparative Example 1>
Example 1 except that the amount of hydroquinone added was changed so that the ratio (A: B) of the number of equivalents of epoxy groups (A) of the epoxy monomer to the number of equivalents (B) of hydroxyl groups of hydroquinone was 100: 7. Thus, an epoxy resin was synthesized. The ratio of the epoxy monomer in the whole epoxy resin obtained was 76%.

  9. 87.4% by mass of the synthesized epoxy resin, 2.6% by mass of boron trifluoride monoethylamine (Wako Pure Chemical Industries, Ltd.) as a curing catalyst, and cyclohexanone (Wako Pure Chemical Industries, Ltd.) as a solvent. A resin composition was prepared by mixing 0% by mass.

  When the prepared resin composition was used to produce a mica tape in the same manner as in Example 1, recrystallization of the epoxy resin was observed, and the impregnation of the resin composition was insufficient. For this reason, the measurement of thermal conductivity was not performed.

  As shown in the results of Table 1, the mica tapes of Examples 1 to 5 produced using an epoxy resin in which the proportion of the epoxy monomer is 70% or less of the entire epoxy resin, the recrystallization of the epoxy resin is suppressed, The impregnation property of the resin composition was excellent. Moreover, the heat conductivity in the hardened state was also high.

In the mica tape of Comparative Example 1 produced using the epoxy resin of Comparative Example 1 in which the proportion of the epoxy monomer exceeds 70% of the total epoxy resin, recrystallization of the epoxy resin was observed and the impregnation property of the resin composition was not good. Since it was sufficient, it is thought that it is not suitable for formation of an insulating layer.
From the above, it was found that the mica tape of this embodiment can form an insulating layer having excellent thermal conductivity.

Claims (13)

A coil conductor and an insulating layer disposed on an outer periphery of the coil conductor, the insulating layer including mica and a cured resin component;
The resin component includes an epoxy resin including a first epoxy compound having one mesogen structure and a second epoxy compound having two or more mesogen structures having the same structure as the mesogen structure,
The coil for rotating electrical machines, wherein the ratio of the first epoxy compound obtained by liquid chromatography is 70% or less of the entire epoxy resin.   The coil for rotating electrical machines according to claim 1, wherein a smectic structure is formed in the cured product of the resin component. A step of disposing a mica tape containing mica and a resin component on the outer periphery of the coil conductor, and a step of forming an insulating layer from the mica tape disposed on the outer periphery of the coil conductor.
The resin component includes an epoxy resin including a first epoxy compound having one mesogen structure and a second epoxy compound having two or more mesogen structures having the same structure as the mesogen structure,
The manufacturing method of the coil for rotary electric machines whose ratio of said 1st epoxy compound obtained by liquid chromatography is 70% or less of the said whole epoxy resin. A mica layer containing mica, and a backing layer containing a backing material, and including a resin component;
The resin component includes an epoxy resin including a first epoxy compound having one mesogen structure and a second epoxy compound having two or more mesogen structures having the same structure as the mesogen structure,
A mica tape in which the proportion of the first epoxy compound obtained by liquid chromatography is 70% or less of the total epoxy resin. The mica tape according to claim 4, wherein the first epoxy compound includes an epoxy compound represented by the following general formula (M).

[In General Formula (M), R < ¹ > -R < ⁴ > shows a hydrogen atom or a C1-C3 alkyl group each independently. ] The mica tape according to claim 4 or 5, wherein the second epoxy compound includes an epoxy compound having two or more structures represented by the following general formula (I).

[In General Formula (I), R < ¹ > -R < ⁴ > shows a hydrogen atom or a C1-C3 alkyl group each independently. ]   The mica tape according to claim 6, wherein the second epoxy compound includes an epoxy compound having two structures represented by the general formula (I). The second epoxy compound includes an epoxy compound having at least one selected from the group consisting of structures represented by the following general formulas (II-A) to (II-D). 8. The mica tape according to any one of 7 above.

[In General Formulas (II-A) to (II-D), R ^{1 to} R ⁴ each independently represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and R ⁵ and R ⁶ each independently represent An alkyl group having 1 to 8 carbon atoms is shown. n and m each independently represents an integer of 0 to 4. Each X independently represents —O— or —NH—. ]   The mica tape according to any one of claims 4 to 8, wherein the resin component exhibits a smectic structure in a cured state.   The cured product of mica tape according to any one of claims 4 to 9, which is obtained by curing the resin component.   An article with an insulating layer, comprising: an insulator; and an insulating layer that is a cured product of the mica tape according to claim 10 disposed on at least a part of a surface of the insulator.   It has a coil conductor and the insulating layer arrange | positioned on the outer periphery of the said coil conductor, The said insulating layer is a coil for rotary electric machines which is the hardened | cured material of the mica tape of Claim 10.   A step of disposing the mica tape according to any one of claims 4 to 9 on the outer periphery of the coil conductor, and a step of forming an insulating layer from the mica tape disposed on the outer periphery of the coil conductor. A method for manufacturing a coil for a rotating electrical machine.