JP2018170252A - Coil for rotary electric machines, prepreg mica tape, method for producing prepreg mica tape, cured product of prepreg mica tape, article with insulating layer, and method for producing coil for rotary electric machines - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a coil for rotary electric machines that has an insulating layer with Tg kept at 180°C or more and excellent thermal conductivity, a method for producing a coil for rotary electric machines, a cured product of a prepreg mica tape, an article with an insulating layer, a prepreg mica tape that can form an insulating layer with Tg kept at 180°C or more and excellent thermal conductivity, and a method for producing a prepreg mica tape.SOLUTION: A coil for rotary electric machines has a coil conductor and an insulating layer disposed around the coil conductor. The insulating layer has a mica layer containing mica, and a backing layer containing a backing material and an inorganic filler. At least one of the mica layer and the backing layer contains a dispersant with an amine value of 60 mgKOH/g or less.SELECTED DRAWING: None

Description

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

  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. doing. As a material for forming the insulating layer, an insulating material containing mica called a mica tape is known.

  Typical examples of the insulating material using mica include prepreg mica tape (resin rich mica tape) and dry mica tape (VPI (vacuum pressure impregnation) mica tape). The prepreg mica tape is mainly composed of a backing layer and a mica layer containing mica, and the mica layer and the backing layer are pre-impregnated with a thermosetting resin. On the other hand, dry mica tape is mainly composed of a backing layer, a mica layer, and an adhesive layer that integrally bonds the backing layer and the mica layer.

When forming an insulating layer using prepreg mica tape, wrap the prepreg mica tape around the part of the insulator that needs insulation, heat it while applying pressure, and let the thermosetting resin pre-impregnated into the prepreg mica tape flow out. While being cured, an insulating layer is formed.
On the other hand, when forming an insulating layer using dry mica tape, wind the dry mica tape around the part of the insulator that requires insulation, then impregnate the wound dry mica tape with a thermosetting resin, and then pressurize The insulating layer is formed by curing the thermosetting resin impregnated in the dry mica tape without heating or under pressure.

  When a prepreg mica tape is used to form an insulating layer contained in the insulator, it is not necessary to impregnate the wound mica tape with the curable resin composition, and thus the manufacturing process tends to be simplified.

  As a prepreg mica tape, for example, a method for producing a prepreg mica tape using a resin containing an inorganic filler containing 1% by mass to 4% by mass of an organic solvent or 1% by mass to 20% by mass of a mixed solution of an organic solvent and a reaction diluent. Is disclosed (for example, see Patent Document 1). According to this method, the boron nitride content is 24% by volume, and the resulting prepreg mica tape cured product has a glass transition temperature of 180 ° C. and a thermal conductivity of 0.62 W / (m · K). It is said that

Japanese Patent Laying-Open No. 2015-199885

  The prepreg mica tape described in Patent Document 1 has a boron nitride content of 24% by volume at the maximum, and it is effective to highly fill boron nitride at 25% by volume or more in order to achieve higher thermal conductivity. As a method for highly filling boron nitride, it is conceivable to use an additive, a large amount of organic solvent, and the like. However, an insulating layer formed using a prepreg mica tape containing an additive and a large amount of an organic solvent has a problem that the glass transition temperature (Tg) is lowered to less than 180 ° C. Further, such an insulating layer is liable to generate voids, and there is a concern about a decrease in thermal conductivity.

  In view of the above circumstances, the present invention provides a coil for a rotating electrical machine having an insulating layer with a glass transition temperature (Tg) maintained at 180 ° C. or higher and excellent thermal conductivity, a method for manufacturing a coil for a rotating electrical machine, and a cured product of a prepreg mica tape. And an article with an insulating layer, a prepreg mica tape capable of forming an insulating layer having a Tg of 180 ° C. or more and excellent thermal conductivity, and a method for producing the prepreg mica tape.

  Specific means for solving the above problems are as follows.

<1> A coil conductor and an insulating layer disposed on an outer periphery of the coil conductor, the insulating layer having a mica layer containing mica, and a backing layer containing a backing material and an inorganic filler, The coil for rotating electrical machines, wherein the mica layer and the backing layer contain a thermosetting resin, and at least one of the mica layer and the backing layer contains a dispersant having an amine value of 60 mgKOH / g or less.
<2> The coil for a rotating electrical machine according to <1>, wherein the inorganic filler has an average particle diameter of 1 μm to 40 μm.
<3> The coil for a rotating electrical machine according to <1> or <2>, wherein the inorganic filler has an aspect ratio of 1 to 10.
<4> The rotating electrical machine coil according to any one of <1> to <3>, wherein the inorganic filler includes boron nitride.
<5> The coil for a rotating electrical machine according to any one of <1> to <4>, wherein the content of the inorganic filler in the insulating layer is 20% by volume to 50% by volume.
<6> When the mica pieces obtained from the mica layer are sieved using a JIS standard sieve, the proportion of mica pieces having a particle diameter of 2.8 mm or more is less than 45% by mass of the whole mica pieces. The coil for rotating electrical machines according to any one of <1> to <5>.
<7> When the mica pieces obtained from the mica layer are sieved using a JIS standard sieve, the proportion of mica pieces having a particle diameter of 0.5 mm or more is 40% by mass or more of the entire mica pieces. The coil for rotating electrical machines according to any one of <1> to <6>.
<8> The coil for a rotating electrical machine according to any one of <1> to <7>, wherein the content of the thermosetting resin in the insulating layer is 25% by mass to 33% by mass.
<9> The coil for a rotating electrical machine according to any one of <1> to <8>, wherein the inorganic filler includes a surface-treated inorganic filler.
<10> A mica layer containing mica and a backing layer containing a backing material and an inorganic filler, wherein the mica layer and the backing layer contain a thermosetting resin, and the mica layer and the backing layer At least one of the prepreg mica tapes contains a dispersant having an amine value of 60 mgKOH / g or less.
<11> The prepreg mica tape according to <10>, wherein the inorganic filler has an average particle diameter of 1 μm to 40 μm.
<12> The prepreg mica tape according to <10> or <11>, wherein the inorganic filler has an aspect ratio of 1 to 10.
<13> The prepreg mica tape according to any one of <10> to <12>, wherein the inorganic filler includes boron nitride.
<14> The prepreg mica tape according to any one of <10> to <13>, wherein the content of the inorganic filler is 20% by volume to 50% by volume.
<15> When the mica pieces obtained from the mica layer are sieved using a JIS standard sieve, the proportion of mica pieces having a particle diameter of 2.8 mm or more is less than 45% by mass of the whole mica pieces. The prepreg mica tape according to any one of <10> to <14>.
<16> When the mica pieces obtained from the mica layer are sieved using a JIS standard sieve, the proportion of mica pieces having a particle diameter of 0.5 mm or more is 40% by mass or more of the entire mica pieces. The prepreg mica tape according to any one of <10> to <15>.
<17> The content rate of the said thermosetting resin is 25 mass%-33 mass% with respect to the total mass of the said mica layer and the said backing layer, It is described in any one of <10>-<16>. Prepreg mica tape.
<18> The prepreg mica tape according to any one of <10> to <17>, wherein the inorganic filler includes a surface-treated inorganic filler.
<19> a step of obtaining a resin composition containing an inorganic filler, a thermosetting resin, and a dispersant having an amine value of 60 mgKOH / g or less; a step of impregnating a backing material and mica paper with the resin composition; The manufacturing method of the prepreg mica tape as described in any one of <10>-<18> which has these.
<20> A cured product of the prepreg mica tape according to any one of <10> to <18>.
<21> an insulator, and an insulating layer that is a cured product of the prepreg mica tape according to any one of <10> to <18> disposed on at least a part of the surface of the insulator. An article with an insulating layer.
<22> An insulating layer is formed from the step of arranging the prepreg mica tape according to any one of <10> to <18> on the outer periphery of the coil conductor, and the prepreg mica tape arranged on the outer periphery of the coil conductor. A method of manufacturing a coil for a rotating electrical machine.

  ADVANTAGE OF THE INVENTION According to this invention, the glass transition temperature (Tg) is maintained at 180 degreeC or more, the coil for rotary electric machines which has the insulating layer which is excellent in thermal conductivity, the manufacturing method of the coil for rotary electric machines, the hardened | cured material of a prepreg mica tape, and insulation An article with a layer, a prepreg mica tape capable of forming an insulating layer having a Tg of 180 ° C. or more and excellent thermal conductivity, and a method for producing the prepreg mica tape can be 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 the present disclosure, 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. .
In the present disclosure, the numerical ranges indicated 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 the present disclosure, 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 description. . Further, in the numerical ranges described in the present disclosure, 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 disclosure, each component may contain a plurality of corresponding substances. When multiple types 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 multiple types of substances present in the composition unless otherwise specified. Means quantity.
In the present disclosure, a plurality of particles corresponding to each component may be included. When a plurality of particles corresponding to each component are present in the composition, the particle diameter of each component means a value for a mixture of the plurality of particles present in the composition unless otherwise specified.
In the present disclosure, the term “layer” refers to a 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. included.
In the present disclosure, the term “lamination” indicates that layers are stacked, and two or more layers may be combined, or two or more layers may be detachable.
In the present disclosure, “(meth) acrylic acid” means at least one of acrylic acid and methacrylic acid.

<Prepreg mica tape>
The prepreg mica tape of the present disclosure (hereinafter sometimes abbreviated as “mica tape”) has a mica layer containing mica and a backing layer containing a backing material and an inorganic filler, and the mica layer and The backing layer contains a thermosetting resin, and at least one of the mica layer and the backing layer contains a dispersant having an amine value of 60 mgKOH / g or less.

  When the mica tape has the above-described configuration, the outflow amount (flow amount) of the thermosetting resin is suppressed, generation of voids is suppressed, and thermal conductivity tends to be improved. Moreover, the fall of glass transition temperature (Tg) is suppressed and it exists in the tendency for Tg of 180 degreeC or more to be maintained. The reason for this is not clear, but is presumed as follows.

There are polar groups such as hydroxy groups on the surface of the inorganic filler. The dispersing agent interacts and adsorbs on this polar group, so that the surface of the inorganic filler becomes lipophilic, the inorganic filler becomes compatible with the thermosetting resin, and the dispersibility of the inorganic filler in the thermosetting resin is improved. improves. Therefore, when a dispersing agent is added, generation | occurrence | production of a void is suppressed and thermal conductivity improves. Moreover, since the dispersibility of the inorganic filler in a thermosetting resin improves, it can be filled with many inorganic fillers, and this also improves thermal conductivity. Furthermore, since the dispersing agent tends to neutralize the acidic or basic functional group present on the surface of the inorganic filler, the decrease in Tg is suppressed. At this time, when the amine value of the dispersant is 60 mgKOH / g or less, the amount of moisture adsorbed on the dispersant is suppressed, the deactivation of the curing catalyst such as the curing agent and the curing accelerator is suppressed, and the Tg is decreased. It is thought that it is effectively suppressed.
In addition, if it has Tg of 180 degreeC or more, it can be accept | permitted in the practical use in which heat resistance is requested | required.

(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 further shaken for 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 conforms to the wet sieving method of JIS-Z-8815: 1994.
“The above sieving is performed using an electromagnetic sieve vibrator at a frequency of 3000 times / minute, an amplitude of 1 mm for 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, the range of ^{100g / m 2 ~200g / m 2} . If the amount of mica in the mica layer is 100 g / m ² or more, a decrease in electrical insulation tends to be suppressed. If the amount of mica in the mica layer is 200 g / m ² or less, the thickness of the mica tape can be made thinner, and the decrease in thermal conductivity tends to be suppressed.

(Lining material)
The type of the backing material contained in the backing layer is not particularly limited. As the backing material, for example, a cloth obtained by using all or a part of fibers made of a polymer material may be used. Examples of the polymer material constituting the cloth include aramid, polyimide, polyester, and the like. When a polymer material is used as part of the fiber, the polymer material may be used for the warp, weft or both of the cloth. You may use together the glass cloth comprised by glass fiber, and a polymer film.

  The average thickness of the backing material is not particularly limited. For example, it is preferably 10 μm to 60 μm, and more preferably 20 μm to 50 μm. If the average thickness of the backing material is 10 μm or more, it is suppressed that the backing layer is too thin following the thickness of the backing material when the mica tape is pressed, and a decrease in thermal conductivity is suppressed. There is a tendency. If the 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.

  The average thickness of the backing material was measured using a micrometer (for example, “MDC-SB” manufactured by Mitutoyo Corporation) at a total of 10 locations, and the arithmetic average value of the obtained measured values was To do.

  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.

(Inorganic filler)
The kind of inorganic filler contained in the backing layer is not particularly limited. 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. Boron nitride may be scaly primary particles or secondary particles formed by agglomeration of primary particles.

  The inorganic filler may be surface-treated. When the surface-treated inorganic filler is used, the dispersibility in the thermosetting resin is further improved and the thermal conductivity tends to be further improved. Examples of the surface treatment include a method using a coupling agent such as a titanium coupling agent and a silane coupling agent.

  The average particle diameter of the inorganic filler is not particularly limited, and is preferably, for example, 1 μm to 40 μm, more preferably 1 μm to 20 μm, and further preferably 1 μm to 10 μm. When the average particle size of the inorganic filler is 1 μm or more, the thermal conductivity and the dielectric strength voltage tend to be improved. When the average particle diameter of the inorganic filler is 40 μm or less, the thermal conductivity anisotropy due to the shape of the particles tends to be suppressed from becoming too large.

  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, the inorganic filler is introduced into pure water and then dispersed with an ultrasonic disperser. By measuring the particle size distribution of the dispersion, the particle size distribution of the inorganic filler is measured. Based on this particle size distribution, the particle size (D50) corresponding to 50% volume accumulation from the small diameter side is determined as the average particle size.

  The aspect ratio (major axis / minor axis) of the inorganic filler is not particularly limited, and is preferably 1 to 10, for example, and more preferably 1 to 5. When the aspect ratio of the inorganic filler is within this range, the anisotropy of the thermal conductivity in the in-plane direction and the thickness direction tends to be suppressed.

The aspect ratio of the inorganic filler is represented by A / B, where A is the length of the inorganic filler in the major axis direction and B is the length in the minor axis direction. The aspect ratio was measured by magnifying the inorganic filler up to 3000 times with a scanning electron microscope, arbitrarily selecting 20 inorganic fillers, measuring A / B, and the arithmetic average value of the measured values. Is taken.
Here, the length in the long axis direction is the distance between A and A ′ when the observed inorganic filler is sandwiched so as to be in contact with two parallel lines A and A ′ and the distance between them becomes the largest. The length in the minor axis direction is such that the inorganic filler is in contact with the two parallel lines B and B ′ perpendicular to the two parallel lines A and A ′ that determine the length in the major axis direction. The distance between B and B ′ when sandwiched.

  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.

  The content of the inorganic filler in the mica tape is preferably 20% by volume or more, and more preferably 25% by volume or more, from the viewpoint of achieving high thermal conductivity. The content of the inorganic filler in the mica tape is preferably 50% by volume or less and preferably 40% by volume or less because the inorganic filler can be easily filled into the thermosetting resin. More preferred.

(Thermosetting resin)
The kind of thermosetting resin is not particularly limited. Examples of the thermosetting resin include epoxy resins, and specific examples include bisphenol A type epoxy resins, bisphenol F type epoxy resins, phenol novolac type epoxy resins, and cresol novolac type epoxy resins.

  The thermosetting resin is present 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 thermosetting resin may further exist outside the mica layer and the backing layer.

The content of the thermosetting resin in the mica tape is not particularly limited, and is preferably 25% by mass or more with respect to the total mass of the mica layer and the backing layer, for example. When the content of the thermosetting resin is 25% by mass or more, the falling off (powder off) of mica and the inorganic filler contained as necessary is suppressed, and the mica tape is cracked when the mica tape is wound around the insulator. As a result of suppressing the occurrence of cuts, wrinkles, etc., there is a tendency that the decrease in insulation reliability and the decrease in thermal conductivity are suppressed. Further, the content of the thermosetting resin in the mica tape includes the mica layer and the backing layer The total mass is preferably 33% by mass or less. When the content of the thermosetting resin is 33% by mass or less, an increase in the thickness of the mica tape is suppressed and good winding properties tend to be maintained.

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

(Dispersant)
The dispersant is contained in at least one of the mica layer and the backing layer. The amine value of the dispersant is 60 mgKOH / g or less, preferably 55 mgKOH / g or less, and more preferably 50 mgKOH / g or less. The lower limit of the amine value of the dispersant is not limited, and the amine value of the dispersant may be 0 mgKOH / g.

The amine value of the dispersant can be measured, for example, according to JIS-K-7237: 1995 as follows.
Weigh 0.1 g of potassium hydrogen phthalate and dissolve in 20 mL of acetic acid. To this solution, 90 mL of o-nitrotoluene is added, and titrated with a 0.1 mol·L ⁻¹ perchloric acid acetic acid solution. On the other hand, the blank test which titrated with the 0.1 mol * L- ¹ perchloric acid acetic acid solution with respect to the mixed solution which mixed o-nitrotoluene and acetic acid by volume ratio 9: 1 is implemented. And a factor is calculated | required from Formula (1).

f = (1000 × m ₁ ) / {204.23 × 0.1 × (V ₁ −V ₂ )} Expression (1)

f: Factor of 0.1 mol·L ⁻¹ perchloric acid acetic acid solution m ₁ : Mass of potassium phthalate V ₁ : Amount of 0.1 mol·L ⁻¹ perchloric acid acetic acid solution consumed for titration to the end point (mL)
V ₂ : 0.1 mol·L ⁻¹ perchloric acid acetic acid solution amount (mL) consumed in the blank test

3 g of the dispersant is weighed and dissolved in a mixed solution in which o-nitrotoluene and acetic acid are mixed at a volume ratio of 9: 1. Three drops of crystal violet indicator are added to the mixed solution containing the dispersant, and titrated with a 0.1 mol·L ⁻¹ perchloric acid acetic acid solution in a burette until the solution turns green. On the other hand, 3 drops of crystal violet indicator are added to a mixed solution in which o-nitrotoluene and acetic acid are mixed at a volume ratio of 9: 1, and titration is performed with a 0.1 mol·L ⁻¹ perchloric acid acetic acid solution to perform a blank test. . And after titrating operation with a 0.1 mol * L- ¹ perchloric acid acetic acid solution twice with respect to the mixed solution containing a dispersing agent and calculating | requiring an average value, an amine titer is calculated from Formula (2).

A = {(56.11 × 0.1 × (V ₃ −V ₄ ) × f) / m ₂ Formula (2)

A: Amine value V ₃ : 0.1 mol·L ⁻¹ perchloric acid acetic acid solution amount (mL) consumed for titration to the end point
V ₄ : 0.1 mol·L ⁻¹ perchloric acid acetic acid solution amount (mL) consumed in the blank test
f: Factor of 0.1 mol·L ⁻¹ perchloric acid acetic acid solution m ₁ : Mass of the weighed dispersant

  The dispersant preferably has both a functional group and a hydrophobic group that interact with the polar group on the surface of the inorganic filler. The functional group of the dispersant interacts with and adsorbs the polar group on the surface of the inorganic filler to make the surface of the inorganic filler oleophilic. The hydrophobic group of the dispersant enhances the compatibility with the thermosetting resin.

  Examples of the dispersant include saturated polyester copolymers, unsaturated polyester copolymers, polycarboxylic acid copolymers, alkyl ammonium salts, unsaturated amine amide salts, polyhydric alcohol ethers, and poly (meth) acrylic acid-polystyrene copolymers. It is done. From the viewpoint of affinity for inorganic fillers, it should be a saturated polyester copolymer, unsaturated polyester copolymer, polycarboxylic acid copolymer, alkylammonium salt, polyhydric alcohol ether, or poly (meth) acrylic acid-polystyrene copolymer. From the viewpoint of heat resistance, a saturated polyester copolymer, an unsaturated polyester copolymer, a polycarboxylic acid copolymer, an alkyl ammonium salt, or a polyhydric alcohol ether is more preferable. Examples of the saturated polyester copolymer include saturated polyester copolymers having a phosphate group.

  The content of the dispersant is not particularly limited, and is preferably 0.1% by mass to 2.0% by mass with respect to the total mass of the inorganic filler, and is 0.1% by mass to 1.5% by mass. It is more preferable that the content is 0.1% by mass to 1.0% by mass.

(Other ingredients)
The mica tape may contain other components other than mica, a backing material, an inorganic filler, a thermosetting resin, and a dispersant as necessary. Examples of other components include a curing agent, a curing accelerator, an organic solvent, a coupling agent, an antioxidant, an antioxidant, a stabilizer, a flame retardant, and a thickener.

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.
Examples of the curing accelerator include imidazole catalysts such as 2-methylimidazole and 2-methyl-4-ethylimidazole, tertiary amine compounds such as trimethylamine, and Lewis acids such as boron trifluoride monoethylamine.

  Examples of the organic solvent include methyl ethyl ketone (MEK), methanol, ethanol, acetone, cyclohexane non and the like. Only one organic solvent may be used, or two or more organic solvents may be used in combination.

  When using an organic solvent, the content of the organic solvent in the varnish used when preparing the mica tape is preferably 60% by mass or less, more preferably 50% by mass or less, and 40% by mass or less. More preferably.

(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 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 tape is preferably 80 μm or more, more preferably 90 μm or more, further preferably 120 μm or more, particularly preferably 150 μm or more, and 160 μm. It is very preferable that it is above.

  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.

  The average thickness of the mica tape was measured with a micrometer (for example, “MDC-SB” manufactured by Mitutoyo Corporation) at a total of 10 locations, and the arithmetic average value of the obtained measurement values To do.

  For the thickness of the mica layer and the backing layer in the mica tape, the thickness of the mica layer and the backing layer in the cross section of the mica tape is observed at three locations with a micrometer of a stereomicroscope (for example, Olympus Corporation “BX51”). The arithmetic average value is used.

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

<Method for producing prepreg mica tape>
The manufacturing method in particular of the prepreg mica tape of this indication is not restrict | limited, A well-known manufacturing method is applicable.
An example of a method for producing mica tape includes a step of obtaining a resin composition containing an inorganic filler, a thermosetting resin, and a dispersant having an amine value of 60 mgKOH / g or less, and the resin composition is used as a backing material and mica. And a method of impregnating paper. Mica paper is a sheet-like material formed by gathering mica. If necessary, the resin composition may contain an organic solvent. By containing the organic solvent, the viscosity of the composition is lowered and the impregnation property tends to be improved.

  Details and preferred embodiments of the mica, the backing material, the thermosetting resin, the inorganic filler and the dispersant contained in the resin composition, and the produced mica tape are as described above.

As an example of the method of impregnating the backing material and mica paper with the resin composition, there is a method in which the resin composition is applied to the backing material and this is bonded to a mica tape. Another example is a method in which a backing material is arranged on mica paper to prepare a laminate, and a resin composition is applied from the backing material side of the laminate.
The resin composition applied to the backing material is preferably carried out so as to ooze out to the other surface side (mica paper side) of the backing material and penetrate into all or part of the mica paper. In this case, even if the mica paper is not a fibrotic mixed paper, the mica paper is likely to be self-supporting and is not easily collapsed. By using mica paper that does not contain fibrites, the electrical insulation and thermal conductivity tend to be improved.

<Hardened prepreg mica tape>
The cured product of the prepreg mica tape of the present disclosure is obtained by curing the thermosetting resin included 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 of the present disclosure includes an insulator and an insulating layer that is a cured product of the prepreg mica tape of the present disclosure disposed on at least a part of the surface of the insulator. The method for forming the insulating layer using the prepreg mica tape of the present disclosure is not particularly limited, and conventionally known production methods can be applied. For example, after the mica tape is wound around the object to be insulated, the mica tape is heated while being pressed (heat press), and the thermosetting resin contained in the mica tape is allowed to flow out of the mica tape in advance to overlap the mica tape. An example is a method in which a space between the tapes is filled with a thermosetting resin, and this is cured to form an insulating layer.

  The insulator to be applied to the article with an insulating layer of the present disclosure is not particularly limited, and examples thereof include a coil conductor of a coil for a rotating electrical machine, bar-shaped copper, and plate-shaped copper.

By using the prepreg mica tape of the present disclosure, an insulating layer having excellent thermal conductivity can be formed. Therefore, when the article with an insulating layer of the present disclosure is a coil, when cooling the coil, a hydrogen cooling method or an air cooling method is also adopted for a coil of a scale that conventionally employs a direct water cooling method. As a result, the coil structure can be simplified.
Moreover, the insulating layer which has Tg of 180 degreeC or more can be formed by using the prepreg mica tape of this indication. Therefore, it can be suitably applied in a practically acceptable range in applications where heat resistance is required, such as coils for rotating electrical machines.

<Coils for rotating electrical machines>
A coil for a rotating electrical machine according to the present disclosure includes a coil conductor and an insulating layer disposed on an outer periphery of the coil conductor, and the insulating layer includes a mica layer including mica, and a backing layer including a backing material and an inorganic filler. The mica layer and the backing layer contain a thermosetting resin, and at least one of the mica layer and the backing layer contains a dispersant having an amine value of 60 mgKOH / g or less.
The details and preferred embodiments of the mica, backing material, thermosetting resin, inorganic filler and dispersant, and manufactured mica layer and backing layer used in the coil for a rotating electrical machine of the present disclosure are as described above. The material, shape, size, etc. of the coil conductor used for the coil for rotating electrical machines are not particularly limited, and can be selected according to the application.

  The content of the inorganic filler in the insulating layer is preferably 20% by volume or more, more preferably 25% by volume or more, and further preferably 30% by volume or more, from the viewpoint of achieving high thermal conductivity. . Further, the content of the inorganic filler in the insulating layer is preferably 50% by volume or less, and preferably 45% by volume or less in order to facilitate filling the thermosetting resin component of the inorganic filler. More preferably, it is more preferably 40% by volume or less.

The content of the thermosetting resin in the insulating layer is not particularly limited, and is preferably 15% by mass or more, for example. When the content of the thermosetting resin is 15% by mass or more, the number of voids inside the insulating layer tends to be suppressed, and the electrical insulation tends to be improved.
Moreover, it is preferable that the content rate of the thermosetting resin in an insulating layer is 30 mass% or less. When the content of the thermosetting resin is 30% by mass or less, the proportion of the inorganic filler in the insulating layer increases, and the thermal conductivity tends to be improved.

<Manufacturing method of coil for rotating electrical machine>
The manufacturing method of the coil for rotating electrical machines of the present disclosure is not particularly limited, and a known manufacturing method can be applied.
As an example of a method for manufacturing a coil for a rotating electrical machine, a step of disposing a prepreg mica tape of the present disclosure on the outer periphery of a coil conductor, and a step of forming an insulating layer from the prepreg mica tape disposed on the outer periphery of the coil conductor; The method which has these.

  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 in particular of forming an insulating layer from the mica tape arrange | positioned on the outer periphery of a coil conductor is not restrict | limited, The method similar to the method demonstrated with the articles | goods with an insulating layer is mentioned.

  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) Production of mica paper Unfired hard mica pieces were dispersed in water and made with a paper machine to produce mica paper having a mica amount of 180 g / m ² .
When the mica was sieved from the produced mica tape by the above-described method, the ratio of mica not passing through the sieve of the JIS standard sieve having a nominal opening of 2.8 mm (hereinafter also referred to as “2.8 mm mica amount on sieve”) ) Was 0% by mass of the whole mica. Further, when sieving using a JIS standard sieve having a nominal mesh size of 0.5 mm, the proportion of mica that does not pass through the sieve mesh (hereinafter also referred to as “0.5 mm mica amount on sieve”) is 63 mass of the whole mica. %Met.

(2) Preparation of Resin Composition Epoxy novolac resin (Dow Chemical Japan Co., Ltd., “D.N.438” (“D.N.” is a registered trademark)) is 33.1% by mass. As a curing accelerator, 1.0% by mass of boron trifluoride monoethylamine (Wako Pure Chemical Industries, Ltd.) and 0.17% by mass of a dispersant (Bic Chemie Japan Co., Ltd., “DISPERBYK-2152”, branched polyester) % And 31.7 mass% (remainder) of methyl ethyl ketone as an organic solvent were mixed. Thereafter, 34.0% by mass of boron nitride (average particle size: 4 μm, aspect ratio: 1.4) was added and further mixed to obtain a resin composition.
In addition, the content rate of the boron nitride with respect to the total solid of a resin composition was 35 volume%.

(3) Preparation of prepreg mica tape The obtained resin composition was coated on a glass cloth (Soyo Corporation, “WEA03G103”, thickness 0.030 mm) with a coater so as to have a thickness of 50 μm. Pasted together. The application was performed so that the resin composition penetrates the entire mica paper in contact with the glass cloth. Then, it dried and produced the laminated body which has a mica layer containing a thermosetting resin, and a glass cloth layer (backing layer). This laminate was cut to a width of 30 mm to obtain a prepreg mica tape.

(4) Preparation of cured prepreg mica tape 16 layers of the obtained prepreg mica tape were laminated and heat-pressed at a pressure of 10 MPa and 110 ° C. for 10 minutes. Thereafter, heat pressing was further performed at a pressure of 10 MPa and 170 ° C. for 60 minutes to obtain a cured product of the prepreg mica tape.

(5) Evaluation The following measurements were performed on the cured product of the obtained prepreg mica tape.

(Thermal conductivity)
A cured product of prepreg mica tape is cut into a circle with a diameter of 50 mm to prepare a sample, and the thermal conductivity (W / (m · K) is measured using a thermal conductivity measuring device (Eihiro Seiki Co., Ltd., “HC-110”). )) Was measured. The thermal conductivity was 0.68 W / (m · K).

(Glass transition temperature (Tg))
Tg of the prepreg mica tape cured product was measured using a dynamic viscoelastic device (TA Instruments, “RSA-G2”). The measurement was performed in a tensile mode at a temperature rising rate of 5 ° C./min and a span distance of 20 mm. Tg was 195 ° C.

<Example 2>
Resin composition in the same manner as in Example 1 except that the dispersant used in Example 1 was replaced with DISPERBYK-2155 (Bic Chemie Japan, Inc., a block copolymer having a basic group having pigment affinity). Was prepared. A prepreg mica tape and a cured product of the prepreg mica tape were produced in the same manner as in Example 1 except that this resin composition and the mica paper shown in Table 1 were used.
The cured product of the prepared prepreg mica tape was measured for thermal conductivity and Tg in the same manner as in Example 1. As a result, the thermal conductivity was 0.68 W / (m · K) and Tg was 198 ° C.

<Example 3>
A resin composition was prepared in the same manner as in Example 1 except that the dispersant used in Example 1 was changed to BYK9076 (Bic Chemie Japan, Inc., alkyl ammonium salt of high molecular weight copolymer). A prepreg mica tape and a cured product of the prepreg mica tape were produced in the same manner as in Example 1 except that this resin composition and the mica paper shown in Table 1 were used.
The cured product of the prepared prepreg mica tape was measured for thermal conductivity and Tg by the same method as in Example 1. As a result, the thermal conductivity was 0.67 W / (m · K), and Tg was 189 ° C.

<Example 4>
A resin composition was prepared in the same manner as in Example 1 except that the dispersant used in Example 1 was changed to DISPERBYK-2200 (Bic Chemie Japan Co., Ltd., high molecular weight copolymer having a pigment affinity group). A prepreg mica tape and a cured product of the prepreg mica tape were produced in the same manner as in Example 1 except that this resin composition and the mica paper shown in Table 1 were used.
The cured product of the prepared prepreg mica tape was measured for thermal conductivity and Tg in the same manner as in Example 1. As a result, the thermal conductivity was 0.70 W / (m · K) and Tg was 194 ° C.

<Comparative Example 1>
A resin composition was prepared in the same manner as in Example 1 except that the dispersant used in Example 1 was replaced by DISPERBYK-106 (Bic Chemie Japan, Inc., a salt of a polymer having an acid group). A prepreg mica tape and a cured product of the prepreg mica tape were produced in the same manner as in Example 1 except that this resin composition was used.
The cured prepreg mica tape was measured for thermal conductivity and Tg in the same manner as in Example 1. As a result, the thermal conductivity was 0.56 W / (m · K) and Tg was 165 ° C.

<Comparative example 2>
A resin composition was prepared in the same manner as in Example 1 except that the dispersant used in Example 1 was replaced with DISPERBYK-180 (Bicchemy Japan Co., Ltd., alkylol ammonium salt of a copolymer having an acid group). did. A prepreg mica tape and a cured product of the prepreg mica tape were produced in the same manner as in Example 1 except that this resin composition was used.
The cured product of the prepared prepreg mica tape was measured for thermal conductivity and Tg in the same manner as in Example 1. As a result, the thermal conductivity was 0.52 W / (m · K), and Tg was 152 ° C.

<Comparative Example 3>
A resin composition was prepared in the same manner as in the preparation of the resin composition of Example 1, except that it was prepared without adding a dispersant. The content of boron nitride relative to the total solid content of the obtained resin composition was 35% by volume. A prepreg mica tape and a cured product of the prepreg mica tape were produced in the same manner as in Example 1 except that this resin composition was used.
The cured product of the obtained prepreg mica tape was measured for thermal conductivity and Tg in the same manner as in Example 1. As a result, the thermal conductivity was 0.64 W / (m · K), and Tg was 165 ° C.

In Table 1, “-” means that no dispersant is added. Moreover, when the amine value of a dispersing agent is described as "0 ^{* 1)} ", it means that the dispersing agent used does not have an amino group.

Claims (22)

  A coil conductor and an insulating layer disposed on an outer periphery of the coil conductor, the insulating layer having a mica layer containing mica, and a backing layer containing a backing material and an inorganic filler, and the mica layer And the backing layer contains a thermosetting resin, and at least one of the mica layer and the backing layer contains a dispersant having an amine value of 60 mgKOH / g or less.   The coil for rotating electrical machines according to claim 1, wherein the inorganic filler has an average particle diameter of 1 μm to 40 μm.   The coil for rotating electrical machines according to claim 1 or 2, wherein an aspect ratio of the inorganic filler is 1 to 10.   The coil for rotating electrical machines according to any one of claims 1 to 3, wherein the inorganic filler includes boron nitride.   The coil for rotating electrical machines according to any one of claims 1 to 4, wherein a content of the inorganic filler in the insulating layer is 20% by volume to 50% by volume.   The ratio of mica pieces having a particle diameter of 2.8 mm or more when the mica pieces obtained from the mica layer are sieved using a JIS standard sieve is less than 45% by mass of the whole mica pieces. The coil for rotating electrical machines according to any one of claims 5 to 6.   When the mica pieces obtained from the mica layer are sieved using a JIS standard sieve, the proportion of mica pieces having a particle diameter of 0.5 mm or more is 40% by mass or more of the whole mica pieces. The coil for rotating electrical machines according to any one of claims 6 to 7.   The coil for rotating electrical machines according to any one of claims 1 to 7, wherein a content of the thermosetting resin in the insulating layer is 25 mass% to 33 mass%.   The coil for rotating electrical machines according to any one of claims 1 to 8, wherein the inorganic filler includes a surface-treated inorganic filler.   A mica layer containing mica, and a backing layer containing a backing material and an inorganic filler, the mica layer and the backing layer contain a thermosetting resin, and at least one of the mica layer and the backing layer is A prepreg mica tape containing a dispersant having an amine value of 60 mgKOH / g or less.   The prepreg mica tape according to claim 10, wherein the inorganic filler has an average particle diameter of 1 μm to 40 μm.   The prepreg mica tape according to claim 10 or 11, wherein the inorganic filler has an aspect ratio of 1 to 10.   The prepreg mica tape according to any one of claims 10 to 12, wherein the inorganic filler contains boron nitride.   The prepreg mica tape as described in any one of Claims 10-13 whose content rate of the said inorganic filler is 20 volume%-50 volume%.   The ratio of mica pieces having a particle diameter of 2.8 mm or more when the mica pieces obtained from the mica layer are sieved using a JIS standard sieve is less than 45% by mass of the whole mica pieces. The prepreg mica tape according to any one of claims 14 to 14.   The ratio of mica pieces having a particle diameter of 0.5 mm or more when the mica pieces obtained from the mica layer are sieved using a JIS standard sieve is 40% by mass or more of the whole mica pieces. The prepreg mica tape according to any one of claims 15 to 15.   The prepreg mica tape according to any one of claims 10 to 16, wherein a content of the thermosetting resin is 25% by mass to 33% by mass with respect to a total mass of the mica layer and the backing layer. .   The prepreg mica tape according to any one of claims 10 to 17, wherein the inorganic filler includes a surface-treated inorganic filler.   A step of obtaining a resin composition containing an inorganic filler, a thermosetting resin, and a dispersant having an amine value of 60 mgKOH / g or less, and a step of impregnating the backing composition and mica paper with the resin composition. The manufacturing method of the prepreg mica tape as described in any one of Claims 10-18.   Hardened | cured material of the prepreg mica tape as described in any one of Claims 10-18.   The insulating layer which has a to-be-insulated body and the insulating layer which is a hardened | cured material of the prepreg mica tape as described in any one of Claims 10-18 arrange | positioned in at least one part of the surface of the to-be-insulated body. Articles with.   The process of arrange | positioning the prepreg mica tape as described in any one of Claims 10-18 on the outer periphery of a coil conductor, The process of forming an insulating layer from the said prepreg mica tape arrange | positioned on the outer periphery of the said coil conductor, The manufacturing method of the coil for rotary electric machines which has these.