WO2014030657A1 - Resin composition for electrical insulation and sheet material - Google Patents

Abstract

Provided is a resin composition for electrical insulation, which contains: at least one resin that is selected from the group consisting of polysulfone resins, polyarylene sulfide resins, polyimide resins and epoxy group-containing phenoxy resins; a polyamide resin; and an inorganic filler. The inorganic filler contains a metal hydroxide or a metal carbonate, and has an average particle diameter of 500 nm or less. Also provided is a sheet material which is provided with a resin layer that is obtained by forming the resin composition for electrical insulation into a sheet-like shape.

Description

Resin composition for electrical insulation and sheet material Cross-reference of related applications

This application claims the priority of Japanese Patent Application No. 2012-183604, which is incorporated herein by reference.

The present invention relates to a resin composition for electrical insulation and a sheet material provided with a resin layer in which the resin composition is formed into a sheet shape.

Conventionally, various types of resin compositions for electrical insulation are known. For example, what is used as a resin composition for electrical insulation is used as a material for coating copper wires in motor enamel wires.

As this kind of resin composition for electrical insulation, specifically, for example, a composition containing a polyimide resin and silica (silicon dioxide) has been proposed (Patent Document 1). Moreover, as this kind of resin composition for electrical insulation, the thing containing an epoxy resin and layered silicate (layered silicate) is proposed, for example (nonpatent literature 1).

However, as described in Patent Document 1, a resin composition for electrical insulation containing a polyimide resin and silica has an insulation deterioration resistance that keeps electrical insulation for a relatively long time when a voltage is applied. There is a problem that it is not necessarily excellent in strength. In addition, as described in Non-Patent Document 1, an electrically insulating resin composition containing an epoxy resin and a layered silicate also has a problem that it is not necessarily excellent in mechanical strength, although it has resistance to insulation deterioration.
That is, the resin composition for electrical insulation as described above has a problem that it is relatively difficult to simultaneously satisfy excellent insulation deterioration resistance and excellent mechanical strength.

Japanese Unexamined Patent Publication No. 2001-307557

The present invention has been made in view of the above-described problems, and an object thereof is to provide a resin composition for electrical insulation that has excellent resistance to insulation deterioration and excellent mechanical strength. It is another object of the present invention to provide a sheet material having excellent insulation deterioration resistance and excellent mechanical strength.

The resin composition for electrical insulation of the present invention comprises at least one selected from the group consisting of a polysulfone resin, a polyarylene sulfide resin, a polyimide resin, and an epoxy group-containing phenoxy resin, a polyamide resin, and an inorganic filler. The inorganic filler contains a metal hydroxide or a metal carbonate, and the average particle size of the inorganic filler is 500 nm or less.

In the resin composition for electrical insulation according to the present invention, the isoelectric point of the inorganic filler is preferably 7 or more.

In the electrically insulating resin composition according to the present invention, the metal hydroxide or the metal carbonate preferably undergoes an endothermic decomposition reaction at a temperature exceeding 330 ° C.

In the resin composition for electrical insulation according to the present invention, the inorganic filler contains the metal hydroxide or metal carbonate, and the metal hydroxide is magnesium hydroxide, calcium hydroxide, or barium hydroxide. It is preferable. In the resin composition for electrical insulation according to the present invention, it is preferable that the inorganic filler contains the metal carbonate, and the metal carbonate is calcium carbonate or magnesium carbonate.

In the resin composition for electrical insulation according to the present invention, the content of the inorganic filler is preferably 1 to 20 parts by mass.

In the resin composition for electrical insulation according to the present invention, the polysulfone resin is preferably a polyethersulfone resin having a plurality of ether bonds in the molecule. The polysulfone resin is preferably a polyphenylsulfone resin having a plurality of aromatic hydrocarbons in the molecule.

In the resin composition for electrical insulation according to the present invention, the polyarylene sulfide resin is preferably a polyphenylene sulfide resin.

In the resin composition for electrical insulation according to the present invention, the polyimide resin is preferably a polyetherimide resin or a polyamideimide resin.

In the resin composition for electrical insulation according to the present invention, the polyamide resin is preferably a polyamide resin having an aromatic hydrocarbon in the molecule.

The sheet material of the present invention is characterized in that the resin composition for electrical insulation is provided with a resin layer formed in a sheet shape.

The sheet material according to the present invention preferably further includes a sheet-like protective layer for protecting the resin layer, and the protective layer is preferably disposed on at least one side of the resin layer.

In the sheet material according to the present invention, the protective layer preferably contains a wholly aromatic polyamide resin.

The sheet material according to the present invention is preferably used for electrical insulation.

Sectional drawing which showed typically the cross section which cut | disconnected the sheet material provided only with the resin layer in the thickness direction. Sectional drawing which showed typically the cross section which cut | disconnected the sheet material provided with the resin layer and the protective layer in the thickness direction. The electron micrograph in the cut surface of the resin composition for electrical insulation (resin layer) of an Example. The electron micrograph in the cut surface of the resin composition for electrical insulation (resin layer) of a comparative example.

Hereinafter, an embodiment of a sheet material according to the present invention will be described with reference to the drawings.

The resin composition for electrical insulation of this embodiment comprises at least one selected from the group consisting of a polysulfone resin, a polyarylene sulfide resin, a polyimide resin, and an epoxy group-containing phenoxy resin, a polyamide resin, and an inorganic filler. And the inorganic filler contains a metal hydroxide or a metal carbonate, and the average particle size of the inorganic filler is 500 nm or less.
The resin composition for electrical insulation of this embodiment has the effect of being excellent in insulation deterioration resistance and excellent in mechanical strength.

The polysulfone resin is a thermoplastic resin having a molecular structure including a plurality of sulfonyl groups (—SO ₂ —).
Examples of the polysulfone resin include a polyethersulfone resin further including a plurality of ether bonds (—O—) in the molecule, and a polyphenylsulfone resin further including a plurality of aromatic hydrocarbons in the molecule. Moreover, as this polysulfone resin, the polyether polyphenyl sulfone resin which further contains a some ether bond and a some aromatic hydrocarbon in a molecule | numerator is mentioned.

As the polysulfone resin, the moldability of the resin composition becomes better, the heat resistance of the resin composition becomes better, and the insulation resistance of the resin composition deteriorates. From the standpoint of better properties, the polyethersulfone resin or the polyphenylsulfone resin is preferable, and the polyether polyphenylsulfone (PES) resin is more preferable.

The polyether polyphenylsulfone (PES) resin preferably has a molecular structure represented by the following formula (1).

As the polyether polyphenylsulfone resin, a commercially available product can be used. For example, commercially available polyether polyphenylsulfone resins include “Ultrazone E series” manufactured by BASF, “Radel A series” manufactured by Solvay, “Sumika Excel series” manufactured by Sumitomo Chemical, and the like. .

The polyarylene sulfide resin is a thermoplastic resin having a plurality of arylene groups and a plurality of sulfide bonds in the molecule. The arylene group is a divalent group of arene (monocyclic or polycyclic aromatic hydrocarbon). Specific examples of the arylene group include a phenylene group, a naphthylene group, an anthrylene group, a phenanthrylene group, and a pyrenylene group.

The polyarylene sulfide resin is preferably a polyphenylene sulfide (PPS) resin having a plurality of phenylene groups and a plurality of sulfide bonds (—S—) in the molecule. When the polyarylene sulfide resin is a polyphenylene sulfide (PPS) resin, there is an advantage that the insulation deterioration resistance of the resin composition is further improved.

The polyimide resin is a thermoplastic resin having a plurality of imide bonds in the molecule.
As the polyimide resin, a polyetherimide (PEI) resin having a plurality of aromatic hydrocarbons, imide bonds and ether bonds in the molecule, or a thermoplastic having a plurality of imide bonds and a plurality of amide bonds in the molecule. Polyamideimide resin is preferred.

The epoxy group-containing phenoxy resin is an epoxy group-containing thermoplastic resin formed by a reaction between a bisphenol compound and epichlorohydrin.
The epoxy group-containing phenoxy resin usually has epoxy groups at both ends of the molecular chain.

The polyamide resin is a thermoplastic resin obtained by polymerizing at least a polyamine compound and a polycarboxylic acid compound by dehydration condensation.

Examples of the polyamide resin include a polyamide resin having an aromatic hydrocarbon in the molecule and an aliphatic polyamide resin having only an aliphatic hydrocarbon as a hydrocarbon in the molecule. Especially, the polyamide resin which has an aromatic hydrocarbon in a molecule | numerator is preferable at the point that the said resin composition can become what was excellent in heat resistance, while being excellent in insulation deterioration resistance.

The polyamide resin having an aromatic hydrocarbon in the molecule includes an aromatic polyamide resin having only an aromatic hydrocarbon as a hydrocarbon in the molecule, an aliphatic hydrocarbon and an aromatic hydrocarbon as a hydrocarbon in the molecule. Examples thereof include semi-aromatic polyamide resins having both.
As the polyamide resin having an aromatic hydrocarbon in the molecule, the semi-aromatic polyamide resin is preferable in that the resin composition can be excellent in mechanical strength while being excellent in insulation deterioration resistance.

Specific examples of the polyamine compound used in the polymerization of the polyamide resin include a diamine compound.
Examples of the diamine compound include aliphatic diamines containing linear or branched hydrocarbon groups, alicyclic diamines containing cyclic saturated hydrocarbon groups, and aromatic diamines containing aromatic hydrocarbon groups. .

Examples of the aliphatic diamine, the alicyclic diamine, or the aromatic diamine include those represented by the following formula (2). R ¹ in the following formula (2) represents an aliphatic hydrocarbon group having 4 to 12 carbon atoms, or an alicyclic hydrocarbon group having 4 to 12 carbon atoms including a cyclic saturated hydrocarbon, or Represents a hydrocarbon group containing an aromatic ring.
H ₂ N—R ¹ —NH ₂ (2)

As the aliphatic diamine, nonanediamine having 9 carbon atoms in R ¹ in formula (2) is preferable in that the resin composition can be more excellent in mechanical strength, and 1,9-nonanediamine and A mixture of 2-methyl-1,8-octanediamine is more preferable.
Examples of the aromatic diamine include phenylenediamine and xylylenediamine.

Specific examples of the polycarboxylic acid compound used in the polymerization of the polyamide resin include a dicarboxylic acid compound.
Examples of the dicarboxylic acid compound include an aliphatic dicarboxylic acid containing a linear or branched hydrocarbon group, an alicyclic dicarboxylic acid containing a cyclic saturated hydrocarbon group, and an aromatic dicarboxylic acid containing an aromatic hydrocarbon group. Etc.

Examples of the aliphatic dicarboxylic acid, the alicyclic dicarboxylic acid, or the aromatic dicarboxylic acid include those represented by the following formula (3). R ² in the following formula (3) represents an aliphatic hydrocarbon group having 4 to 25 carbon atoms, or an alicyclic hydrocarbon group having 4 to 12 carbon atoms including a cyclic saturated hydrocarbon, or Represents a hydrocarbon group containing an aromatic ring.
HOOC-R ² -COOH (3)

Examples of the aliphatic dicarboxylic acid include adipic acid and sebacic acid.
Examples of the aromatic dicarboxylic acid include terephthalic acid, methyl terephthalic acid, and naphthalene dicarboxylic acid. As the aromatic dicarboxylic acid, terephthalic acid can be used because the heat resistance of the polyamide resin can be further improved. Acid is preferred.

The polyamide resin may be one obtained by polymerizing one kind of diamine compound and one kind of dicarboxylic acid compound, or may be one obtained by polymerizing a combination of plural kinds of each compound. Good. Further, if necessary, a material obtained by further polymerizing a compound other than the diamine compound and the dicarboxylic acid compound may be used.

As described above, the polyamide resin is preferably the semi-aromatic polyamide resin. As the semi-aromatic polyamide resin, an aliphatic diamine as a diamine compound and an aromatic dicarboxylic acid as a dicarboxylic acid compound are polymerized. More preferred are those obtained by polymerizing nonanediamine as an aliphatic diamine and terephthalic acid as an aromatic dicarboxylic acid (PA9T).

Commercially available products can be used as the polyamide resin. Specifically, examples of commercially available polyamide resins include “Genester” series manufactured by Kuraray Co., Ltd.

The resin composition for electrical insulation preferably contains 50% by mass or more of at least one thermoplastic resin selected from the group consisting of a polysulfone resin, a polyarylene sulfide resin, a polyimide resin, and an epoxy group-containing phenoxy resin. More preferably, the content is 60% by mass or more. When the resin composition for electrical insulation contains 50% by mass or more of such a thermoplastic resin, there is an advantage that the insulation deterioration resistance of the resin composition for electrical insulation becomes more excellent.
The resin composition for electrical insulation contains 90% by mass or less of at least one thermoplastic resin selected from the group consisting of a polysulfone resin, a polyarylene sulfide resin, a polyimide resin, and an epoxy group-containing phenoxy resin. Is preferable, and it is more preferable to contain 85 mass% or less. When the resin composition for electrical insulation contains such a thermoplastic resin in an amount of 90% by mass or less, the mechanical strength of the resin composition for electrical insulation is further improved, and insulation deterioration due to discharge in the resin composition for electrical insulation is caused. There is an advantage that it is more suppressed.

The electrical insulating resin composition preferably contains 5% by mass or more of the polyamide resin, more preferably 10% by mass or more. When the resin composition for electrical insulation contains 5% by mass or more of the polyamide resin, there is an advantage that the mechanical strength and creeping insulation of the resin composition for electrical insulation can be further improved.
Moreover, the resin composition for electrical insulation preferably contains 50% by mass or less of the polyamide resin, more preferably 40% by mass or less, and further preferably 30% by mass or less. When the resin composition for electrical insulation contains a polyamide resin in an amount of 50% by mass or less, there is an advantage that the discharge deterioration of the resin composition for electrical insulation is further suppressed, and as described later, the protective layer 3 and the resin layer There exists an advantage that the delamination between 2 can be suppressed more.

The resin composition for electrical insulation preferably contains the polysulfone resin and the polyamide resin in a mass ratio of polysulfone resin / polyamide resin = 60/40 to 90/10. By including the polysulfone resin and the polyamide resin at a mass ratio in such a range, there is an advantage that the mechanical strength and heat resistance of the resin composition for electrical insulation are further improved.

The resin composition for electrical insulation may contain other thermoplastic resins in addition to the above-described thermoplastic resins.
As the other thermoplastic resin, for example, a polyacetal (POM) resin having a plurality of oxymethylene (—CH 2 O—) groups in the molecule; a basic structure of an aromatic hydrocarbon-ether bond is repeated in the molecule Polyphenylene oxide (PPO) resin such as polyphenylene ether (PPE) resin; aromatic polyether ketone (PEK) resin in which the basic structure of aromatic hydrocarbon-ether bond-aromatic hydrocarbon-ketone bond is repeated in the molecule An aromatic polyetherketone (PEEK) resin in which the basic structure of aromatic hydrocarbon-ether bond-aromatic hydrocarbon-ether bond-aromatic hydrocarbon-ketone bond is repeated in the molecule; polyethylene, polypropylene, poly Polyolefin resins such as cycloolefin; acrylonitrile, butadiene and Aromatic-containing vinyl resins such as copolymers with ABS (ABS resin); Polyester resins such as polyethylene naphthalate (PEN) resin, polybutylene terephthalate (PBT) resin, polyethylene terephthalate (PET) resin; Polycarbonate (PC) Resin; liquid crystal polymer (LCP); thermoplastic elastomer resin and the like.

The inorganic filler is an inorganic compound that, when blended in the resin composition for electrical insulation, enhances the insulation deterioration resistance of the resin composition for electrical insulation, compared to those that do not contain an inorganic filler.

In the resin composition for electrical insulation of this embodiment, the thermoplastic resin described above and the inorganic filler are included, and the average particle diameter of the inorganic filler is 500 nm or less, and the inorganic filler is At least one of a metal hydroxide and a metal carbonate is contained.

When a high voltage is applied to the resin composition for electrical insulation, a discharge phenomenon (hereinafter also referred to as partial discharge) may occur in a part of the resin composition for electrical insulation. The charged particles generated by the partial discharge can collide with the molecular chains of the resin contained in the resin composition to break the molecular chains, or thermally decompose the molecular chains by heat accompanying the collision. Moreover, ozone is generated by partial discharge, and the ozone can cause deterioration of the resin contained in the resin composition. With such a phenomenon, it is considered that a fracture path extends in the resin composition, and the electrical insulation of the resin composition can be lowered.

In the resin composition for electrical insulation of this embodiment, since the average particle diameter of an inorganic filler is 500 nm or less, the number of inorganic fillers per unit mass of the inorganic filler is relatively large. As the number of inorganic fillers increases, it is considered that the elongation of the fracture path described above is likely to be hindered by individual inorganic fillers.
Therefore, the resin composition for electrical insulation of this embodiment can have excellent insulation deterioration resistance. That is, the resin composition for electrical insulation of this embodiment can have a relatively long electrical insulation life.

On the other hand, if the average particle diameter of the inorganic filler exceeds 500 nm, the elongation of the fracture path as described above is difficult to be hindered, and the insulation deterioration resistance of the resin composition for electrical insulation may be insufficient. Moreover, when the average particle diameter of an inorganic filler exceeds 500 nm, there exists a possibility that the mechanical strength of the resin composition for electrical insulation may become inadequate.

The average particle diameter of the inorganic filler is preferably 100 nm or less. When the average particle diameter is 100 nm or less, the number of inorganic fillers is increased for the same reason as described above, so that the insulation deterioration resistance of the resin composition for electrical insulation can be further improved. There are advantages.
Moreover, it is preferable that the average particle diameter of the said inorganic filler is 10 nm or more. When the average particle size is 10 nm or more, there is an advantage that the aggregation of the inorganic filler in the electrically insulating resin composition is further suppressed and the inorganic filler is more easily dispersed in the electrically insulating resin composition.

The average particle diameter of the inorganic filler is a value determined by the following method.
That is, the average particle diameter of the inorganic filler is the primary particle diameter of 1000 inorganic fillers in an observed image (magnification: 10,000 times) obtained with a scanning electron microscope (Hitachi High-Tech, product name “S-3400N”). Calculate by averaging. Specifically, the observation image is obtained by analyzing the horizontal ferret diameter by image analysis software (product name “A image kun” manufactured by Asahi Kasei Engineers), and determining and averaging the horizontal ferret diameter of each inorganic filler.
In order to obtain an observation image, an inorganic filler is dispersed in acetone so as to have a concentration of 0.1% by mass, and a dispersion is prepared. After the dispersion is dropped onto a glass plate, the acetone is evaporated and dried. A sample is prepared. And the average particle diameter of an inorganic filler is calculated | required by observing this sample for observation.
If the shape of the inorganic filler is a needle shape, the inorganic filler in a state where the longitudinal direction of the inorganic filler is substantially parallel to the glass plate surface is set as the analysis target. Moreover, if the shape of an inorganic filler is plate shape, let the inorganic filler of the state which the plate | board surface of the inorganic filler opposed the glass plate surface be analysis object.

In the resin composition for electrical insulation of the present embodiment, the inorganic filler contains at least one of a metal hydroxide and a metal carbonate. Therefore, deterioration of the resin composition for electrical insulation is suppressed even under high temperature conditions due to application of voltage.
Specifically, the metal hydroxide decomposes by releasing water molecules while absorbing heat when the temperature exceeds a predetermined temperature. Similarly, when the metal carbonate reaches a predetermined temperature or higher, it releases carbon dioxide and decomposes while absorbing heat. As described above, when the metal hydroxide and the metal carbonate reach a predetermined temperature or higher, they undergo an endothermic decomposition reaction that decomposes while absorbing heat. Therefore, when an inorganic filler containing a metal hydroxide or metal carbonate is present in the resin composition, the temperature of the resin composition increases due to an endothermic decomposition reaction of the metal hydroxide or metal carbonate under high temperature conditions. Is suppressed. Thereby, deterioration by the heat | fever of a resin composition is suppressed and the fall of the electrical insulation of the resin composition accompanying heat deterioration is suppressed. Therefore, the resin composition for electrical insulation of this embodiment is excellent in resistance to insulation deterioration.

At least one of the metal hydroxide and the metal carbonate preferably undergoes an endothermic decomposition reaction at a temperature exceeding 330 ° C. When the metal hydroxide or the metal carbonate undergoes an endothermic decomposition reaction at a temperature exceeding 330 ° C., there is an advantage that the insulation deterioration resistance of the resin composition for electrical insulation is further improved. . That is, there is an advantage that the electrical insulation life of the resin composition for electrical insulation becomes longer.
Specifically, in the production of the resin composition for electrical insulation, each of the above-described blending components is usually heated and mixed at a temperature of 280 to 320 ° C. Therefore, a metal hydroxide or metal carbonate that undergoes an endothermic decomposition reaction at a temperature exceeding 330 ° C. does not cause an endothermic decomposition reaction even in the above temperature range in production. As a result, even if a part of the resin composition for electrical insulation reaches a temperature exceeding 330 ° C. due to the application of voltage, the metal hydroxide or metal carbonate undergoes an endothermic decomposition reaction, thereby suppressing the temperature rise. It is done. That is, as the endothermic decomposition reaction occurs, the temperature increase of the resin composition for electrical insulation is suppressed, and the thermal deterioration of the resin composition for electrical insulation is suppressed. Thus, the insulation deterioration resistance of the resin composition for electrical insulation becomes more excellent.

The metal hydroxide or the metal carbonate usually undergoes an endothermic decomposition reaction at a temperature of 800 ° C. or lower.

The temperature at which the endothermic decomposition reaction occurs is determined by measurement by differential thermal-thermogravimetric analysis (TG-DTA).
Specifically, differential thermal-thermogravimetric analysis is performed on metal hydroxide or metal carbonate while heating at a rate of temperature increase of 10 ° C./min under an inert gas stream. Then, the temperature at which an endothermic peak begins to occur in the differential thermal analysis is observed, and the temperature at which weight reduction starts in the thermogravimetric analysis is observed. From the results, the temperature at which weight loss starts in thermogravimetric analysis is defined as the temperature at which the endothermic decomposition reaction occurs.

More specifically, for example, magnesium hydroxide as a metal hydroxide starts to generate an endothermic peak at 340 ° C. in a differential thermal-thermogravimetric analysis (TG-DTA) under the above conditions, and has an endothermic peak at about 400 ° C. A vertex appears. Magnesium hydroxide begins to lose weight at 340 ° C. Therefore, the temperature at which magnesium hydroxide undergoes an endothermic decomposition reaction is 340 ° C.
Thus, magnesium hydroxide begins to undergo an endothermic decomposition reaction from 340 ° C., decomposes while absorbing heat, and releases water molecules having a relatively large heat capacity.

If the metal hydroxide or the metal carbonate is a hydrate, in the differential thermal-thermogravimetric analysis (TG-DTA), the weight loss due to desorption of hydrated water molecules is regarded as an endothermic decomposition reaction. Not considered.

The isoelectric point of the inorganic filler is preferably 7 or more, more preferably 8 or more, and still more preferably 9 or more. When the isoelectric point is 7 or more, there is an advantage that the dispersibility of the inorganic filler in the resin composition for electrical insulation is further improved.
The isoelectric point of the inorganic filler is preferably 12 or less. When the isoelectric point is 12 or less, there is an advantage that the dispersibility of the inorganic filler in the resin composition for electrical insulation is further improved.
Regarding the relationship between the isoelectric point of the inorganic filler and the dispersibility of the inorganic filler in the resin composition for electrical insulation, the surface charge state of the inorganic filler using the isoelectric point of the inorganic filler as an index, and the resin composition for electrical insulation This can be explained based on the interaction with the amide bond of the polyamide resin contained in the product.
Specifically, the inorganic filler usually has a hydroxyl group that is a polar group on the surface. And the aspect of a hydroxyl group changes according to the surrounding pH environment in an inorganic filler. Specifically, assuming that the inorganic filler is present in water, when the pH of the water is lower than the isoelectric point of the inorganic filler, the form of the hydroxyl group on the surface of the inorganic filler changes and the surface charge becomes positive. On the other hand, when the pH of water is higher than the isoelectric point of the inorganic filler, the surface charge of the inorganic filler becomes negative. Thus, the surface charge of the inorganic filler can vary depending on the surrounding pH environment.
Further, in the resin composition for electrical insulation, not only inorganic fillers but also polyamide resins are present in a dispersed state. Since the polyamide resin has an amide bond, it has a relatively high polarity and exhibits neutral to weak basicity.
In the state where the polyamide resin and the inorganic filler coexist, the inorganic filler exists in a neutral to weakly basic environment due to the polyamide resin, and the surface of the inorganic filler is positively charged by the isoelectric point of the inorganic filler. It can be negatively charged or uncharged. Therefore, an inorganic filler having an isoelectric point of about 2 is positively charged in the presence of a neutral to weakly basic polyamide resin, while an inorganic filler having an isoelectric point of about 8 is neutral to In the presence of a polyamide resin exhibiting weak basicity, the surface may be hardly charged. An inorganic filler having an isoelectric point of about 11 can be negatively charged on the surface in the presence of a polyamide resin, but the difference between the weak basicity exhibited by the polyamide resin and the isoelectric point is relatively small. Therefore, an inorganic filler having an isoelectric point of about 11 is considered to be in a relatively weak charged state even when charged.
From this, when the isoelectric point of the inorganic filler is 7 or more (alkali side), the inorganic filler in the coexistence with the polyamide resin can have a relatively small surface charge. Therefore, the polarity of the inorganic filler due to the surface charge becomes relatively small, and the interaction (hydrogen bond or the like) caused by the polarity of the inorganic filler and the polarity of the polyamide resin can be further reduced. That is, the ionic bond between the inorganic filler and the polyamide resin can be suppressed. Therefore, adsorption of the inorganic filler to the polyamide resin in the resin composition for electrical insulation is suppressed, and as a result, the dispersibility of the inorganic filler becomes better.

The isoelectric point of the inorganic filler is measured according to JIS R1638 "4.1 Electrophoresis method b) Electrophoretic laser / Doppler method".

The hardness of the inorganic filler is not particularly limited, but is preferably 7 or less in Mohs hardness.
The Mohs hardness is determined by evaluating using 10 kinds of standard minerals. Specifically, the standard mineral is scratched with an inorganic filler to check whether the standard mineral is damaged. That is, the standard mineral is sequentially changed from the standard mineral having the lowest hardness to the standard mineral having the highest hardness, and the hardness of the standard mineral causing the scratch is defined as the Mohs hardness.

The metal hydroxide is preferably at least one selected from the group consisting of magnesium hydroxide, calcium hydroxide, and barium hydroxide. The metal hydroxide is at least one selected from the group consisting of magnesium hydroxide, calcium hydroxide, and barium hydroxide, so that the resin composition for electrical insulation has better insulation deterioration resistance There is an advantage that can be.
The temperature at which the endothermic decomposition reaction of magnesium hydroxide occurs is 340 ° C., the temperature at which the endothermic decomposition reaction of calcium hydroxide occurs is 580 ° C., and the temperature at which the endothermic decomposition reaction of barium hydroxide occurs is 780 ° C. It is.

The metal carbonate is preferably at least one of calcium carbonate and magnesium carbonate. When the metal carbonate is at least one of calcium carbonate and magnesium carbonate, there is an advantage that the electrical insulation resin composition can be more excellent in insulation deterioration resistance.
The temperature at which the endothermic decomposition reaction of calcium carbonate occurs is 600 ° C., and the temperature at which the endothermic decomposition reaction of magnesium carbonate (anhydride) occurs is 500 ° C.

The content of the inorganic filler in the resin composition for electrical insulation is preferably 1% by mass or more, and more preferably 4% by mass or more. The content of the inorganic filler in the resin composition for electrical insulation is preferably 20% by mass or less, more preferably 10% by mass or less, and further preferably 6% by mass or less.
When the content ratio of the inorganic filler is 1% by mass or more, there is an advantage that the insulating deterioration resistance of the resin composition for electrical insulation can be further improved. Moreover, when the content rate of an inorganic filler is 20 mass% or less, there exists an advantage that the mechanical strength of the resin composition for electrical insulation can become more excellent.

In the resin composition for electrical insulation, it is preferable that aggregation of inorganic fillers is suppressed. That is, the aggregation degree of the aggregated particles of the inorganic filler in the resin composition for electrical insulation is preferably 500 nm or less, and more preferably 350 nm or less.
When the aggregation degree of the aggregated particles of the inorganic filler is 500 nm or less, the elongation of the breakdown path due to the voltage as described above is further suppressed, and the insulation deterioration resistance of the resin composition for electrical insulation is more excellent. There are advantages. Moreover, since the aggregation degree of the aggregated particle of an inorganic filler is 500 nm or less, the aggregated particle becomes relatively small. Therefore, there is an advantage that the resin composition starting from the aggregated particle is hardly broken. That is, there is an advantage that the mechanical strength of the resin composition for electrical insulation, specifically, the tear resistance of the resin composition for electrical insulation is improved.

The degree of aggregation of the above-mentioned inorganic filler aggregated particles in the electrical insulating resin composition is determined by the following method.
That is, a sheet-shaped resin composition for electrical insulation was cut in the thickness direction along the MD direction, and the cross section was scanned with a scanning electron microscope (product name “S-3400N” manufactured by Hitachi High-Tech). Observe to obtain image data (magnification 10,000 times). Further, the image data is analyzed by image analysis software (product name “A Image-kun”, manufactured by Asahi Kasei Engineers).
Specifically, the degree of aggregation of the aggregated particles of the inorganic filler is measured by the method described in the examples.
In addition, since the measurement method differs from the measurement method of the average particle diameter of the inorganic filler, the aggregation degree of the inorganic filler aggregate particles in the resin composition for electrical insulation is not necessarily the average particle diameter (average primary particle diameter) of the inorganic filler. That's not necessarily the case.

The inorganic filler may be subjected to a surface treatment.
Examples of the surface treatment agent for the surface treatment include organic silane compounds. Examples of the organic silane compound include vinyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, p-styryltrimethoxysilane, 3-isocyanatopropyltriethoxysilane, 3-methacryloxypropyltrimethoxysilane, Examples include 3-acryloxypropyltrimethoxysilane, N-2- (aminoethyl) -3-aminopropylmethyldimethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, and the like. The surface treatment agent can be used in an amount of, for example, 0.01 to 5 parts by weight with respect to 100 parts by weight of the inorganic filler that has not been surface-treated.

Various additives may be blended in the resin composition for electrical insulation.
Examples of such additives include alkylphenol resins, alkylphenol-acetylene resins, xylene resins, coumarone-indene resins, terpene resins, rosin and other tackifiers, brominated flame retardants such as polybromodiphenyl oxide and tetrabromobisphenol A, Chlorinated flame retardants such as chlorinated paraffin and perchlorocyclodecane, phosphorus flame retardants such as phosphate esters and halogenated phosphate esters, boron flame retardants, oxide flame retardants such as antimony trioxide, phenolic, Inorganic fillers including phosphorous and sulfur antioxidants, silica, clay, aluminum oxide, magnesium oxide, boron nitride, silicon nitride, or aluminum nitride, heat stabilizers, light stabilizers, ultraviolet absorbers, lubricants, pigments , Crosslinking agent, crosslinking aid, silane coupling agent, titanate Including general plastic compounding ingredients such as coupling agents and the like. Moreover, aromatic polyamide fibers, montmorillonite having a particle size of several nm to several hundred nm, and the like can be mentioned. These additives may be contained, for example, in an amount of 0.1 to 5% by mass in the resin composition for electrical insulation.

The resin composition for electrical insulation can be produced by mixing the above-described thermoplastic resin, inorganic filler, and if necessary, an additive while appropriately heating by a general method. Specifically, the resin composition for electrical insulation can be produced, for example, by mixing using a general mixing means such as a kneader, a pressure kneader, a kneading roll, a Banbury mixer, or a twin screw extruder. it can.

Next, an embodiment of the sheet material according to the present invention will be described with reference to the drawings. 1 and 2 are cross-sectional views schematically showing a cross section obtained by cutting the sheet material of the present embodiment in the thickness direction.

The sheet material 1 of this embodiment is provided with a resin layer 2 in which the resin composition for electrical insulation is formed into a sheet shape as shown in FIG.

As shown in FIG. 2, the sheet material 1 further includes a sheet-like protective layer 3 that protects the resin layer 2, and the protective layer 3 is disposed on at least one side of the resin layer 2. preferable.
For example, as shown in FIG. 2, the sheet material 1 includes a resin layer 2 and two protective layers 3 disposed on both sides of the resin layer 2. Further, in such a sheet material 1, the protective layer 3 is disposed so as to contact both surfaces of the resin layer 2.
The thickness of the sheet material 1 is usually 1 μm to 1000 μm.

The shape of the resin layer 2 is not particularly limited as long as the resin composition for electrical insulation is formed in a sheet shape.
The thickness of the resin layer 2 is not particularly limited, and is usually 1 μm to 500 μm.

The protective layer 3 is not particularly limited as long as it is a sheet. The thickness of the protective layer 3 is not particularly limited, and is usually 10 to 500 μm.

Examples of the protective layer 3 include paper, nonwoven fabric, and film. The protective layer 3 is preferably paper or non-woven fabric in that delamination between the protective layer 3 and the resin layer 2 can be further suppressed.

Examples of the protective layer 3 include those prepared by a wet papermaking method and those prepared by a dry method in the air.
The protective layer 3 is preferably paper produced by a wet papermaking method in that delamination between the protective layer 3 and the resin layer 2 can be further suppressed.

Examples of the material of the protective layer 3 include synthetic polymer compounds such as polyamide resin and polyester resin, and natural polymer compounds such as cellulose. The material is preferably a polyamide resin in that delamination between the protective layer 3 and the resin layer 2 can be further suppressed.

The polyamide resin of the protective layer 3 is a wholly aromatic polyamide resin in which all of the constituent monomers have aromatic hydrocarbons, an aliphatic polyamide resin in which all of the constituent monomers have only aliphatic hydrocarbons as hydrocarbons, Examples thereof include semi-aromatic polyamide resins partially having aromatic hydrocarbons. The polyamide resin is preferably a wholly aromatic polyamide resin in that delamination between the protective layer 3 and the resin layer 2 can be further suppressed. That is, it is preferable that the protective layer 3 contains the wholly aromatic polyamide resin.

Further, the protective layer 3 includes fibers of wholly aromatic polyamide resin in that delamination between the protective layer 3 and the resin layer 2 can be further suppressed, and that the flame retardancy is excellent. A wholly aromatic polyamide paper is more preferred, and a wholly aromatic polyamide paper produced by wet papermaking using fibers of wholly aromatic polyamide resin is more preferred.

As the wholly aromatic polyamide paper, for example, a wholly aromatic polyamide obtained by fiberizing a condensation polymerization product (fully aromatic polyamide resin) of phenylenediamine and phthalic acid having a benzene ring other than an amide group. The thing formed as a main component material is mentioned.
The wholly aromatic polyamide paper is excellent in mechanical properties and preferably has a basis weight of 5 g / m ² or more in terms of good handling in the production process of the sheet material 1. When the basis weight is 5 g / m ² or more, there is an advantage that insufficient mechanical strength is suppressed and the sheet material 1 is not easily broken during production.

In addition, other components can be added to the wholly aromatic polyamide paper as long as the effects of the present invention are not impaired. Examples of the other components include polyphenylene sulfide fibers, polyether ether ketone fibers, polyester fibers, and arylates. Examples thereof include organic fibers such as fibers, liquid crystal polyester fibers, and polyethylene naphthalate fibers, or inorganic fibers such as glass fibers, rock wool, asbestos, boron fibers, and alumina fibers.

As the wholly aromatic polyamide paper, for example, those commercially available from DuPont under the trade name “NOMEX” can be used.

The protective layer 3 is preferably subjected to a corona treatment on the resin layer 2 side. The corona treatment is advantageous in that delamination between the protective layer 3 and the resin layer 2 can be further suppressed.
In the corona treatment, one surface of the protective layer 3 in contact with the resin layer 2 is subjected to a discharge treatment to generate a polar carboxyl group or hydroxyl group on one surface of the protective layer 3. This is a process for roughening the surface. As the corona treatment, a conventionally known general method can be employed.

In the sheet material 1, it is preferable that the agglomeration degree of the agglomerated particles of the inorganic filler is 500 nm or less, like the resin composition for electrical insulation described above. That is, the aggregation degree of the aggregated particles of the inorganic filler in the resin layer 2 is preferably 500 nm or less.

The sheet material 1 includes a resin layer 2 and a protective layer 3 that are in contact with each other, and layer indirect between the resin layer 2 and the protective layer 3 due to the cohesive failure force of the resin layer 2 and the protective layer 3. It is preferable to be configured to increase the wearing force. With such a configuration, delamination between the resin layer 2 and the protective layer 3 is suppressed.

The sheet material 1 can be manufactured by a general method.
For example, the sheet material 1 having only the resin layer 2 can be produced by extruding the resin composition for electrical insulation mixed as described above into a sheet shape by an extruder equipped with a T-die. Or the sheet | seat material 1 provided only with the resin layer 2 can be manufactured by shape | molding the resin composition for electrical insulation in a sheet form with an injection molding machine.
Moreover, the sheet material 1 provided with the resin layer 2 and the two protective layers arranged on both sides of the resin layer 2 presses, for example, a material in which the resin layer 2 is sandwiched between two protective layers 3 from both sides. Can be manufactured.

The sheet material 1 can be used for electrical insulation by utilizing the point of electrical insulation. For example, the sheet material 1 can be used in an electrical insulation sheet for a motor, an electrical insulation sheet for a transformer (transformer), an electrical insulation sheet for a bus bar, and the like in an automobile or the like.

The resin composition for electrical insulation and the sheet material of the present embodiment are as illustrated above, but the present invention is not limited to the resin composition for electrical insulation and the sheet material illustrated above.
Moreover, the various aspects used in the resin composition for electrical insulation and a sheet | seat material are employable in the range which does not impair the effect of this invention.

Next, the present invention will be described in more detail with reference to examples, but the present invention is not limited thereto.

A resin composition for electrical insulation was produced using the raw materials shown below.
・ Polysulfone resin:
Polyether polyphenylsulfone resin (PES) resin containing a plurality of sulfonyl groups and further containing a plurality of ether bonds and a plurality of aromatic hydrocarbons (product name “Ultrazone E2000” manufactured by BASF)
・ Polyamide resin:
Polyamide (PA) resin containing terephthalic acid units and nonanediamine units (PA9T Kuraray Co., Ltd., trade name “Genesta N1000A”)
・ Inorganic filler (Material: Magnesium hydroxide, Shape: Plate)
(Product name “MGZ-3” manufactured by Sakai Chemical Industry Co., Ltd.) Average particle size: 100 nm
Isoelectric point -12, endothermic decomposition start temperature -340 ° C
・ Inorganic filler (Material: Magnesium hydroxide, Shape: Plate)
(Product name “MGZ-1” manufactured by Sakai Chemical Industry Co., Ltd.) Average particle size 800 nm
Isoelectric point -12, endothermic decomposition start temperature -340 ° C
・ Inorganic filler (material: calcium carbonate, shape: rectangular parallelepiped)
(Product name “CALCIES” manufactured by Kamishima Chemical Co., Ltd.) Average particle size 60 nm
Isoelectric point-9, endothermic decomposition reaction start temperature-600 ° C
・ Inorganic filler (Material: Silica, Shape: Spherical)
(Product name “Special” manufactured by Sakai Chemical Co., Ltd.)
Isoelectric point -2, endothermic decomposition reaction start temperature-none (no endothermic decomposition reaction occurs)

Moreover, the following were used as a protective layer.
・ Fully aromatic polyamide paper (2 sheets)
(DuPont brand name "NOMEX T410" thickness 50μm)
Corona treatment is applied to the surface in contact with the resin layer under the following conditions.
Equipment-PILLAR TECHNOLOGIES "500 Series"
Pressure-atmospheric pressure, output-500W, processing speed-4m / min, sample width-0.4m

(Example 1)
Using a biaxial kneader (manufactured by Technobel), PES resin and PA resin were mixed (dry blended) at 300 ° C. so that the mass ratio of PES / PA = 80/20. Next, this resin mixture and magnesium hydroxide were further mixed at a mass ratio of resin mixture / magnesium hydroxide = 96/4 to prepare a resin composition for electrical insulation.
Subsequently, the resin composition for electrical insulation was molded into a sheet having a thickness of 100 μm at 300 ° C. by extrusion molding to form a resin layer.
In this way, a sheet material (width 15 cm × length 10 m) having only the resin layer was produced.

(Example 2)
A sheet material was produced in the same manner as in Example 1 except that the resin mixture and magnesium hydroxide were mixed so that the mass ratio of resin mixture / magnesium hydroxide = 94/6.

(Example 3)
Example 1 except that calcium carbonate is used in place of magnesium hydroxide as the inorganic filler, and the resin mixture and magnesium hydroxide are mixed so that the mass ratio of resin mixture / magnesium hydroxide = 94/6. A sheet material was produced in the same manner as described above.

Example 4
A resin layer was formed in the same manner as in Example 1 except that the resin mixture and magnesium hydroxide were mixed at a mass ratio of resin mixture / magnesium hydroxide = 94/6.
Furthermore, wholly aromatic polyamide paper was disposed on each side of the resin layer. Furthermore, the sheet | seat material (200 micrometers thickness) provided with the resin layer and the protective layer was manufactured by pressing for 5 minutes by pressure 4MPa with the hot press machine which was pinched | interposed between two metal plates and heated to 250 degreeC.

(Comparative Example 1)
A resin composition for electrical insulation was prepared in the same manner as in Example 1 except that the inorganic filler was not blended, and a resin layer having a thickness of 100 μm was formed using this resin composition for electrical insulation.

(Comparative Example 2)
A resin layer having a thickness of 100 μm was formed in the same manner as in Example 1 except that silica was used instead of magnesium hydroxide as the inorganic filler.

(Comparative Example 3)
Instead of magnesium hydroxide having an average particle diameter of 100 nm as the inorganic filler, the above-mentioned magnesium hydroxide having an average particle diameter of 800 nm was used, and the resin mixture and magnesium hydroxide were mixed with resin mixture / magnesium hydroxide = 94/6. A resin layer having a thickness of 100 μm was formed in the same manner as in Example 1 except that the mixing was performed so that the mass ratio became.

(Comparative Example 4)
A resin composition for electrical insulation was prepared in the same manner as in Example 1 except that the inorganic filler was not blended, and a resin layer having a thickness of 100 μm was formed using this resin composition for electrical insulation.
Further, in the same manner as in Example 4, a sheet material (200 μm thickness) provided with this resin layer and a protective layer was produced.

<Evaluation of insulation deterioration resistance (electrical insulation life)>
For the sheet-like samples manufactured in each Example and each Comparative Example, the time until dielectric breakdown was measured in a normal temperature atmosphere using a pressure tester (Tokyo Seimitsu Co., Ltd., high frequency pressure tester “TSH-510”). did. Specifically, the applied voltage was set to 25 kV / mm for Examples 1 to 3 and Comparative Examples 1 to 3, and the applied voltage was set to 20 kV / mm for Example 4 and Comparative Example 4. In addition, a cylindrical electrode having a diameter of 25 mm was used as the electrode. After measuring 10 points on the measurement sample, a Weibull distribution of breakdown time was created, and the time when the cumulative occurrence probability was 63.2% was defined as the average insulation life time.

<Evaluation of mechanical strength (tear resistance test)>
In accordance with “end tear resistance (Method B)” in JIS C2151, the end tear resistance values when the electrical insulating sheet was torn along the longitudinal (MD) direction were measured at 23 ° C., respectively.

<Measurement of aggregation degree of aggregated particles>
The aggregation degree of the aggregated particles in the samples (resin layers) of Examples 1 to 4 and Comparative Examples 2 and 3 was measured as follows.
Each sample was cut along the MD direction, and the cross section was observed with a scanning electron microscope (manufactured by Hitachi High-Tech, device name “S-3400N”) to obtain image data (magnification 10,000 times). Furthermore, this image data was subjected to image processing, and then image analysis was performed using image analysis software (product name “A Image-kun”, manufactured by Asahi Kasei Engineers).
Image processing First, an image obtained by observation with a scanning electron microscope (SEM) was binarized using image analysis software (National Institutes of Health [NIH] open source, name “Image J”). . Since the inorganic filler is displayed in the bright part on the SEM image, in binarization, first, light / dark reversal was performed so that the inorganic filler was displayed in the dark part. After that, by correcting the brightness and contrast, the inorganic filler was made to stand out, and only the inorganic filler was selected by setting the threshold value to obtain a binarized image.
-Image analysis Next, the obtained binarized image was analyzed using image analysis software (product name "A image kun", manufactured by Asahi Kasei Engineers). In addition, the dark part in a binarized image was made into the inorganic filler, and the inorganic filler which overlaps with the outer edge of a rectangular analysis range (8.5 micrometers x 12.7 micrometers) was excluded from the analysis object. In addition, when there are voids inside the inorganic fillers that are gathered together in the binarized image, the process of filling the voids is not performed, and the process of separating the inorganic fillers that are in contact with each other is not performed in the binarized image It was. For inorganic fillers such as needles and plates, the area displayed in the image may differ depending on the cutting direction of the sheet molded product of the resin composition. However, in this method, it analyzed uniformly by said operation irrespective of the shape of an inorganic filler.
The diameter (equivalent circle diameter) when the aggregated particles are assumed to be a perfect circle is calculated from the area of each aggregated particle obtained by image analysis under the condition setting as described above, and the diameter is represented by a frequency distribution. did.
Then, the median diameter (that is, the cumulative frequency 50% diameter) that is the median value of the frequency distribution is obtained, and further, the equivalent of the aggregated particles that are the target of those having a circle equivalent diameter that is twice or more the median diameter. The degree of aggregation of the aggregated particles was calculated by averaging the diameters.

Tables 1 and 2 show the configurations of the sheet materials of each Example and each Comparative Example and the above evaluation results. The image data in Example 1 and Comparative Example 2 are shown in FIGS. 3 and 4, respectively.

In Examples 1 to 4, referring to the degree of aggregation of the aggregated particles, the aggregation of the inorganic filler was suppressed and the dispersibility was good. On the other hand, in Comparative Examples 2 and 3, aggregation of the inorganic filler was confirmed.
In addition, in the frequency distribution in Comparative Examples 2 and 3 (see “Measurement of the degree of aggregation of aggregated particles” above), the distribution of aggregated particles was also present at a circle equivalent diameter of, for example, 800 nm. That is, in Comparative Examples 2 and 3, relatively large aggregated particles existed.
On the other hand, in the frequency distribution in each example, for example, there was no distribution of aggregated particles at a circle-equivalent diameter of about 800 nm, and relatively large aggregated particles as in Comparative Examples 2 and 3 did not exist.
Further, when observing the image data, as shown in FIG. 4, the aggregation of the inorganic filler in Comparative Example 2 was remarkably generated along the polyamide resin portion in the resin composition.

As can be seen from the above results, in the examples, compared with the comparative examples, the insulation deterioration resistance (electrical insulation life) is excellent and the mechanical strength (tearing resistance) is also excellent.

The sheet material containing the resin composition for electrical insulation of the present invention can be suitably used as an electrical insulation sheet that requires electrical insulation, mechanical strength, and workability. Specifically, for example, an electrical insulation member disposed around the motor coil wire, an electrical insulation member for a transformer, a busper, a capacitor, a cable, or an electrical insulation sheet for a module terminal such as an electronic circuit board or IGBT It is suitable for such applications.

1: Sheet material, 2: Resin layer, 3: Protective layer.

Claims (15)

1. Including at least one selected from the group consisting of a polysulfone resin, a polyarylene sulfide resin, a polyimide resin, and an epoxy group-containing phenoxy resin, a polyamide resin, and an inorganic filler,
   The inorganic filler contains a metal hydroxide or a metal carbonate;
   The resin composition for electrical insulation whose average particle diameter of the said inorganic filler is 500 nm or less.
2. The resin composition for electrical insulation according to claim 1, wherein the inorganic filler has an isoelectric point of 7 or more.
3. The resin composition for electrical insulation according to claim 1 or 2, wherein the metal hydroxide or the metal carbonate undergoes an endothermic decomposition reaction at a temperature exceeding 330 ° C.
4. The resin for electrical insulation according to any one of claims 1 to 3, wherein the inorganic filler contains the metal hydroxide, and the metal hydroxide is magnesium hydroxide, calcium hydroxide, or barium hydroxide. Composition.
5. The resin composition for electrical insulation according to any one of claims 1 to 3, wherein the inorganic filler contains the metal carbonate, and the metal carbonate is calcium carbonate or magnesium carbonate.
6. 6. The resin composition for electrical insulation according to claim 1, wherein the content of the inorganic filler is 1 to 20% by mass.
7. The resin composition for electrical insulation according to any one of claims 1 to 6, wherein the polysulfone resin is a polyethersulfone resin having a plurality of ether bonds in a molecule.
8. The resin composition for electrical insulation according to any one of claims 1 to 7, wherein the polysulfone resin is a polyphenylsulfone resin having a plurality of aromatic hydrocarbons in a molecule.
9. The resin composition for electrical insulation according to any one of claims 1 to 8, wherein the polyarylene sulfide resin is a polyphenylene sulfide resin.
10. The resin composition for electrical insulation according to any one of claims 1 to 9, wherein the polyimide resin is a polyetherimide resin or a polyamideimide resin.
11. The resin composition for electrical insulation according to any one of claims 1 to 10, wherein the polyamide resin is a polyamide resin having an aromatic hydrocarbon in a molecule.
12. A sheet material provided with a resin layer in which the resin composition for electrical insulation according to any one of claims 1 to 11 is formed into a sheet shape.
13. The sheet material according to claim 12, further comprising a sheet-like protective layer for protecting the resin layer, wherein the protective layer is disposed on at least one side of the resin layer.
14. The sheet material according to claim 13, wherein the protective layer contains a wholly aromatic polyamide resin.
15. The sheet material according to any one of claims 12 to 14, which is used for electrical insulation.

Images