Insulation film for motor, motor and method for manufacturing insulation film for motor

Abstract

To provide an insulation film which prevents buckling when an insulation film is inserted into a motor, and suppresses occurrence of breakage and cracking in the film when the film is bent.SOLUTION: An insulation film for a motor includes a resin and an inorganic filler, wherein a value (E'1 / E'2) obtained by dividing tensile elastic modulus (E'1) in a first direction by tensile elastic modulus (E'2) in a second direction orthogonal to the first direction is 1.2 or more. There are provided a motor having the insulation film for the motor, and a method for manufacturing the insulation film for the motor.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to an insulating film for a motor, a motor, and a method for manufacturing an insulating film for a motor. [Background technology]

[0002] Motors that drive home appliances, industrial equipment, and other devices have traditionally been equipped with slot paper or wedge paper that blocks the slot groove openings from the inside as insulating films interposed between the core and the winding coil in the slots in the stator core. These insulating films are typically folded to fit the openings and then inserted into the slots through the openings on the end faces of the stator core. To prevent tearing during insertion into the stator core, the insulating film must have high folding resistance and strength.

[0003] In recent years, there has been a demand for compact, highly efficient motors. To this end, methods have been studied for increasing the space factor of winding coils by thinning insulating films, for example. For example, Patent Document 1 discloses a coil insulating sheet containing a thermosetting resin and an inorganic filler. Patent Document 1 aims to obtain a coil insulating sheet with high thermal conductivity in order to efficiently remove heat generated from miniaturized motors. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 2021-86998 Summary of the Invention [Problem to be solved by the invention]

[0005] In recent years, motors have become smaller, which has led to a demand for thinner insulating films. However, simply making insulating films thinner can result in insufficient film strength, which can lead to problems such as buckling when the insulating film is inserted into the motor.

[0006] On the other hand, adding various fillers to insulating films can be considered to increase their strength, but adding fillers reduces the film's folding resistance, which can lead to breakage or cracking when the film is bent and molded.

[0007] Therefore, in order to solve these problems of the conventional technology, the inventors conducted research with the aim of providing an insulating film that is less likely to buckle when inserted into a motor and that is less likely to break or crack when the film is bent. [Means for solving the problem]

[0008] Examples of specific embodiments of the present invention are given below.

[0009] [1] Contains resin and inorganic filler. An insulating film for motors, in which the value (E'1 / E'2) obtained by dividing the tensile modulus of elasticity in a first direction (E'1) by the tensile modulus of elasticity in a second direction (E'2) perpendicular to the first direction is 1.2 or more. [2] The insulating film for motors according to [1], wherein the resin has a glass transition temperature of 50 to 300°C. [3] The insulating film for motors according to [1] or [2], wherein the resin has a tensile modulus of elasticity of 1.0 GPa or more. [4] The insulating film for a motor according to any one of [1] to [3], wherein the resin is a thermoplastic resin. [5] The insulating film for motors according to [4], wherein the thermoplastic resin is at least one selected from the group consisting of polyetherimide, polyaryletherketone, thermoplastic polyimide, aromatic polyamide, aromatic polyester, and polycarbonate. [6] The insulating film for a motor according to any one of [1] to [5], wherein the inorganic filler is acicular. [7] The insulating film for a motor according to any one of [1] to [6], wherein the inorganic filler is at least one selected from the group consisting of titanium oxide, zinc oxide, alumina, aluminum nitride, boron nitride, boehmite, potassium titanate, and calcium titanate. [8] The insulating film for a motor according to any one of [1] to [7], which has a tensile modulus of elasticity (E'1) in the first direction of 5 to 10 GPa. [9] The insulating film for a motor according to any one of [1] to [8], which has a tensile modulus of elasticity (E'2) in the second direction of 2 to 9 GPa.

[10] The insulating film for motors according to any one of [1] to [9], which has a compressive strength in the first direction at a thickness of 200 μm of 700 N or more.

[11] The insulating film for a motor according to any one of [1] to

[10] , which has a thickness of 20 to 500 μm.

[12] A laminated insulating film for motors, comprising an insulating paper for motors according to any one of [1] to

[11] and aramid paper on at least one side thereof.

[13] A motor comprising the insulating film for a motor according to any one of [1] to

[11] .

[14] A method for producing a laminated insulating film for motors, comprising kneading a resin and an inorganic filler having an aspect ratio of 5 to 100 and forming the mixture into a film.

[15] The method for producing a laminated insulating film for motors according to

[14] , wherein the resin has a glass transition temperature of 50 to 300°C.

[16] The method for producing a laminated insulating film for motors according to

[14] or

[15] , wherein the resin has a tensile modulus of elasticity of 1.0 GPa or more.

[17] The method for producing an insulating film for a motor according to any one of

[14] to

[16] , wherein the resin is a thermoplastic resin.

[18] The method for producing a laminated insulating film for motors according to

[17] , wherein the thermoplastic resin is at least one selected from the group consisting of polyetherimide, polyaryletherketone, thermoplastic polyimide, aromatic polyamide, aromatic polyester, and polycarbonate.

[19] The method for producing a laminated insulating film for motors according to any one of

[14] to

[18] , wherein the inorganic filler is at least one selected from the group consisting of titanium oxide, zinc oxide, alumina, aluminum nitride, boron nitride, boehmite, potassium titanate, and calcium titanate. [Effects of the Invention]

[0010] According to the present invention, it is possible to provide an insulating film that is less likely to buckle when inserted into a motor and that is less likely to break or crack when folded. DETAILED DESCRIPTION OF THE INVENTION

[0011] The present invention will be described in detail below. The following description may be based on representative embodiments or specific examples, but the present invention is not limited to such embodiments. In this specification, when "X to Y" (X and Y are arbitrary numbers) is used, it means "X or more and Y or less" unless otherwise specified, and also includes "preferably greater than X" or "preferably less than Y." Furthermore, when "X or more" (X is an arbitrary number) or "Y or less" (Y is an arbitrary number), it also includes the meaning "preferably greater than X" or "preferably less than Y." In the following description, the terms "film" and "sheet" are not clearly distinguished from each other, and the term "film" includes the term "sheet," and the term "sheet" includes the term "film."

[0012] (Insulating film for motors) This embodiment relates to an insulating film for motors (hereinafter, sometimes referred to as "the insulating film") that contains a resin and an inorganic filler and has a value (E'1 / E'2) obtained by dividing the tensile modulus of elasticity in a first direction (E'1) by the tensile modulus of elasticity in a second direction (E'2) perpendicular to the first direction, that is, 1.2 or greater. The value (E'1 / E'2) obtained by dividing the tensile modulus of elasticity in the first direction (E'1) by the tensile modulus of elasticity in the second direction (E'2) perpendicular to the first direction is preferably 1.3 or greater, more preferably 1.4 or greater, and even more preferably 1.5 or greater. The upper limit of the value of E'1 / E'2 is not particularly limited, but is preferably 5 or less, more preferably 4 or less, and even more preferably 3 or less.

[0013] In this specification, the first direction of the insulating film is preferably either the machine direction (MD) or the width direction (TD) of the film, and more preferably the machine direction (MD) of the film. The second direction of the insulating film is a direction perpendicular to the first direction. When the first direction of the insulating film is the machine direction (MD) of the film, the second direction is the width direction (TD) of the film, and when the first direction is the width direction (TD) of the film, the second direction is the machine direction (MD) of the film. That is, the first direction of the insulating film is more preferably the machine direction (MD) of the film, and the second direction is preferably the width direction (TD) of the film. However, when the machine direction and the width direction of the insulating film are unknown, it is preferable to define the first direction as, for example, the direction in which the needle-shaped inorganic filler (described later) is oriented.

[0014] The present embodiment has the above-described configuration, which makes it difficult for the insulating film to buckle when inserted into a motor, and also prevents the film from breaking or cracking when folded. This allows the insulating film to be made thinner, making it particularly suitable for use in miniaturized motors. Furthermore, when a thinner insulating film is used, the space factor of the winding coil in the motor can be increased, enabling the motor to have higher output.

[0015] In the present insulating film, the compressive strength in the first direction at a thickness of 200 μm is preferably 700 N or more, more preferably 725 N or more, even more preferably 750 N or more, and particularly preferably 800 N or more. The upper limit of the compressive strength in the first direction at a thickness of 200 μm is not particularly limited, but is preferably 3000 N or less, more preferably 2500 N or less, and even more preferably 2000 N or less. By keeping the compressive strength in the first direction within the above range, buckling can be suppressed when the insulating film is inserted into a motor. In this specification, the first direction is preferably the direction in which the acicular inorganic particles are oriented, and this direction is preferably the machine direction (MD). If the compressive strength in the first direction is equal to or greater than the above lower limit, it can be evaluated as being less likely to buckle when the insulating film is inserted into a motor.

[0016] This insulating film has excellent flex resistance, and for example, when the film is bent 180 degrees along the machine direction (MD), the film is prevented from breaking or cracking. More specifically, even when the film is bent 180 degrees along the machine direction (MD) three times, the film is prevented from breaking or cracking all three times.

[0017] The tensile modulus (E'1) of the insulating film in the first direction at room temperature (23°C) is preferably 5 GPa or more, more preferably 5.5 GPa or more, and even more preferably 6 GPa or more. The upper limit of the tensile modulus (E'1) of the insulating film in the first direction is not particularly limited, but is, for example, preferably 50 GPa or less, more preferably 40 GPa or less, even more preferably 30 GPa or less, even more preferably 20 GPa or less, and particularly preferably 10 GPa or less. By keeping the tensile modulus (E'1) in the first direction at room temperature (23°C) within the above range, the strength of the insulating film can be increased and the occurrence of buckling and breakage or cracking when bent can be effectively suppressed.

[0018] The tensile modulus (E'2) of the insulating film in the second direction at room temperature (23°C) is preferably 2 GPa or more, more preferably 2.5 GPa or more, even more preferably 3 GPa or more, and even more preferably 3.5 GPa or more. The upper limit of the tensile modulus (E'2) of the insulating film in the second direction is not particularly limited, but is, for example, preferably 45 GPa or less, more preferably 35 GPa or less, even more preferably 25 GPa or less, even more preferably 15 GPa or less, and particularly preferably 9 GPa or less. By keeping the tensile modulus (E'2) in the second direction at room temperature (23°C) within the above range, the strength of the insulating film can be increased and the occurrence of buckling and breakage or cracking when bent can be effectively suppressed.

[0019] The tensile modulus of elasticity of this insulating film is measured at a temperature of 23°C in accordance with JIS K7127:1999.

[0020] The thickness of the insulating film is preferably 20 μm or more, more preferably 30 μm or more, and even more preferably 40 μm or more. The thickness of the insulating film is preferably 500 μm or less, more preferably 400 μm or less, even more preferably 300 μm or less, and particularly preferably 200 μm or less. In this way, in this embodiment, the thickness of the insulating film can be reduced, which results in an increased coil space factor within the motor and improved motor efficiency.

[0021] The insulating film preferably has a single layer structure, but may have a multilayer structure. When the insulating film has a multilayer structure, each layer may contain a different resin, may be composed of the same type of resin, or may be composed of a laminate of thermosetting resin films, nonwoven fabrics, etc. Furthermore, it is sufficient that the inorganic filler is contained in at least one layer.

[0022] (resin) The insulating film contains a resin. The resin may be either a thermoplastic resin or a thermosetting resin, but as will be described later, the resin is preferably a thermoplastic resin because this makes it easier to obtain a film in which the inorganic filler is oriented in one direction during molding.

[0023] The glass transition temperature of the resin is preferably 50° C. or higher, more preferably 90° C. or higher, and even more preferably 140° C. or higher. The glass transition temperature of the resin is preferably 300° C. or lower, more preferably 280° C. or lower, and even more preferably 260° C. or lower. By setting the glass transition temperature of the resin within the above range, it is possible to more effectively improve the buckling resistance and the processability of the film.

[0024] The resin may be a crystalline resin or an amorphous resin. In the case of a crystalline resin, the crystalline melting temperature (melting point) is preferably 150°C or higher, more preferably 200°C or higher, and even more preferably 250°C or higher. The crystalline melting temperature (melting point) is preferably 500°C or lower, more preferably 400°C or lower, and even more preferably 350°C or lower. By setting the crystalline melting temperature (melting point) of the resin within the above range, it is possible to more effectively improve the buckling resistance and the processability of the film.

[0025] The tensile modulus of the resin is preferably 1.0 GPa or more, more preferably 1.5 GPa or more, and even more preferably 2.0 GPa or more. The tensile modulus of the resin is preferably 20.0 GPa or less, more preferably 15.0 GPa or less, and even more preferably 10.0 GPa or less. By setting the tensile modulus of the resin within the above range, buckling resistance and bending resistance can be more effectively improved. The tensile modulus of the resin is a value obtained by measuring a sample obtained by injection molding resin pellets at a temperature of 23°C in accordance with ISO 527.

[0026] Examples of the resin include thermoplastic resins and thermosetting resins. Examples of the thermoplastic resin include at least one selected from the group consisting of polyetherimide, polyaryletherketone, thermoplastic polyimide, polyphenylene ether, polyetherimide sulfone, polyphenylene sulfide, polyarylate, polysulfone, polyethersulfone, polyamideimide, polystyrene, aromatic polyamide, aromatic polyester, and polycarbonate. Among these, the thermoplastic resin is preferably a thermoplastic resin having an aromatic group, and is preferably at least one selected from the group consisting of polyetherimide, polyaryletherketone, polyphenylene ether, polyphenylene sulfide, aromatic polyamide, and polycarbonate, and particularly preferably at least one selected from the group consisting of polyetherimide and polyaryletherketone. Examples of the thermosetting resin include at least one selected from the group consisting of epoxy resin, polyurethane, polyolefin, silicone resin, polyimide, polyphenol, and acrylic resin.

[0027] The content of the resin contained in the insulating film is preferably 30% by mass or more, more preferably 40% by mass or more, even more preferably 50% by mass or more, even more preferably 60% by mass or more, and particularly preferably 65% ​​by mass or more, based on the total mass of the insulating film. The content of the resin contained in the insulating film is preferably 95% by mass or less, more preferably 90% by mass or less, and even more preferably 85% by mass or less, based on the total mass of the insulating film.

[0028] <Polyetherimide> Polyetherimide (hereinafter sometimes referred to as "PEI") is an amorphous resin having imide groups. There are no particular limitations on the polyetherimide, and its production method and properties are described in, for example, U.S. Patents 3,905,942 and 3,803,085.

[0029] Specifically, the PEI preferably has a repeating unit represented by the following structural formula (1): Whether a polyetherimide resin is amorphous can be determined by DSC.

[0030] [ka]

[0031] In equation (1), Y 1 ~Y 6 each independently represents a hydrogen atom, an alkyl group, or an alkoxy group; Ar 7 ~Ar 9 each independently represents an arylene group having 6 to 24 carbon atoms which may have a substituent; X 1 represents a single bond, or any of -O-, -SO2-, -S-, -C(=O)-, and a divalent aliphatic hydrocarbon group.

[0032] The polyetherimide preferably has a structure in which the repeating unit represented by the above formula (1) is repeated, for example, 10 to 1000 times, and the number of repeating units (n) is more preferably 20 to 700, and even more preferably 30 to 500. If the number of repeating units is within the above range, the viscosity when melted is not too high, and the moldability is excellent, and various properties such as heat resistance and heat aging resistance tend to be well-balanced.

[0033] Y 1 ~Y 6 The alkyl group in the formula (I) is, for example, an alkyl group having 1 to 20 carbon atoms, preferably 1 to 10 carbon atoms, more preferably 1 to 6 carbon atoms, and even more preferably 1 to 2 carbon atoms. Specific preferred examples include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, an n-pentyl group, an isopentyl group, a neopentyl group, a 1-methylpentyl group, an n-hexyl group, and an isohexyl group. Also, Y 1 ~Y 6The alkoxy group in the formula (I) is, for example, an alkoxy group having 1 to 20 carbon atoms, preferably 1 to 10 carbon atoms, more preferably 1 to 6 carbon atoms, and even more preferably 1 or 2 carbon atoms. Specifically, preferred examples include a methoxy group, an ethoxy group, an n-propoxy group, an isopropoxy group, an n-butoxy group, a sec-butoxy group, a tert-butoxy group, an n-pentyloxy group, and an n-hexyloxy group. Y 1 ~Y 6 may be the same or different. 1 ~Y 6 At least one of Y is preferably a hydrogen atom. 1 ~Y 6 It is more preferable that all of are hydrogen atoms.

[0034] Ar 7 ~Ar 9 Examples of the arylene group in the formula include a phenylene group, a naphthylene group, and an anthracenylene group. Examples of the substituent of the arylene group include an alkyl group, a halogen, an alkoxy group, a halogen-substituted alkyl group, etc. The alkyl group and alkoxy group as the substituent have, for example, 1 to 6 carbon atoms, preferably 1 to 2 carbon atoms, and specific examples thereof are as described above. A halogen-substituted alkyl group is an alkyl group in which one or more hydrogen atoms are substituted with halogen. The alkyl group in the halogen-substituted alkyl group is the same as described above. Examples of halogen include a chlorine atom, a bromine atom, a fluorine atom, and an iodine atom. 7 ~Ar 9 may be the same or different. 7 ~Ar 9 When Ar has a substituent, the number of carbon atoms in the arylene group is preferably 6 to 24. 7 ~Ar 9 is preferably a phenylene group which may have a substituent, and among these, a phenylene group is preferred.

[0035] X1 The divalent aliphatic hydrocarbon group in the formula (I) is preferably a divalent aliphatic hydrocarbon group having 1 to 6 carbon atoms, and more preferably a divalent saturated aliphatic hydrocarbon group having 1 to 6 carbon atoms. y H 2y X is represented by - (y is an integer of 1 to 6), and specific examples include a methylene group, a dimethylene group, a trimethylene group, a propylene group, an ethylidene group (-CH(CH3)-), and a dimethylmethylene group (-C(CH3)2-). 1 is preferably a divalent saturated aliphatic hydrocarbon group, and more preferably a dimethylmethylene group (-C(CH3)2-).

[0036] In the above formula (1), Ar 9 may be a 1,4- or 1,3-arylene group having 6 to 24 carbon atoms which may have a substituent, but is preferably a 1,4-arylene group having 6 to 24 carbon atoms which may have a substituent. When the bonding positions with the imide group are the 1 and 4 positions, the structure is stable and heat aging resistance tends to be improved. Therefore, it is preferable that the polyetherimide has a repeating unit represented by the following structural formula (2).

[0037] [ka]

[0038] In equation (2), Y 1 ~Y 6 each independently represents a hydrogen atom, an alkyl group, or an alkoxy group; Ar 7 ~Ar 9 each independently represents an arylene group having 6 to 24 carbon atoms which may have a substituent; X 1 represents a single bond, or any of -O-, -SO2-, -S-, -C(=O)-, and a divalent aliphatic hydrocarbon group. 9 The imide group is Ar 9 This indicates that the bond is at the 1st and 4th positions of the group.

[0039] Y in equation (2) 1 ~Y 6 , X 1 is as explained above. Ar 9 Examples of the arylene group in Ar include a 1,4-phenylene group, a 1,4-naphthylene group, and a 1,4-anthracenylene group. These arylene groups may have a substituent as described above, and the substituent is as described above. 9 is preferably a 1,4-phenylene group which may have a substituent, and more preferably a 1,4-phenylene group.

[0040] In formula (2), Ar 7 , Ar 8 is as explained above, but Ar 7 and Ar 8 is preferably a 1,4-arylene group having 6 to 24 carbon atoms which may have a substituent, and examples of the 1,4-arylene group include a 1,4-phenylene group, a 1,4-naphthylene group, and a 1,4-anthracenylene group. These arylene groups may have a substituent as described above, and the substituent is as described above. Ar 7 and Ar 8 is more preferably a 1,4-phenylene group which may have a substituent, and even more preferably a 1,4-phenylene group.

[0041] In particular, it is particularly preferable that the polyetherimide used in the present insulating film has a repeating unit represented by the following structural formula (3). When the polyetherimide has the following structure, the present insulating film tends to have excellent mechanical properties, excellent crystallinity, heat resistance, and good adhesion to aramid paper. Furthermore, it tends to have good moldability and secondary processability.

[0042] [ka]

[0043] In formula (3), the number of repeating units (n) is preferably 10 to 1000, more preferably 20 to 700, and even more preferably 30 to 500. When the number of repeating units (n) is within the above range, the viscosity when melted is not too high, resulting in excellent moldability, and a good balance of various properties such as heat resistance and heat aging resistance tends to be achieved.

[0044] More specifically, the polyetherimide particularly preferably has a repeating unit represented by the following structural formula (4) or (5): In formulas (4) and (5), the number of repeating units (n) is preferably 10 to 1000, more preferably 20 to 700, and even more preferably 30 to 500. When the number of repeating units (n) is within the above range, the viscosity when melted is not too high, resulting in excellent moldability, and a good balance of various properties such as heat resistance and heat aging resistance tends to be achieved. [ka]

[0045] The polyetherimide resin having the structure represented by the above structural formula (4) is a polycondensate (meta-polyetherimide) of 4,4'-[isopropylidenebis(p-phenyleneoxy)]diphthalic dianhydride and m-phenylenediamine, and the polyetherimide resin having the structure represented by the structural formula (5) is a polycondensate (para-polyetherimide) of 4,4'-[isopropylidenebis(p-phenyleneoxy)]diphthalic dianhydride and p-phenylenediamine.

[0046] The glass transition temperature of PEI is preferably 160°C or higher, more preferably 170°C or higher, even more preferably 180°C or higher, even more preferably 190°C or higher, and particularly preferably 200°C or higher. The glass transition temperature of PEI is preferably 300°C or lower, more preferably 290°C or lower, even more preferably 280°C or lower, even more preferably 270°C or lower, and particularly preferably 260°C or lower. If the glass transition temperature is equal to or higher than the lower limit, a resin film having sufficient heat resistance is more easily obtained. If the glass transition temperature is equal to or lower than the upper limit, molding processability at low temperatures is more easily achieved.

[0047] The tensile modulus of PEI is preferably 2.0 GPa or more, more preferably 2.3 GPa or more, and even more preferably 2.5 GPa or more, and preferably 10.0 GPa or less, more preferably 8.0 GPa or less, and even more preferably 6.0 GPa or less.

[0048] As PEI, for example, products commercially available from Sabic Innovative Plastics under the trade name "Ultem" series can be used.

[0049] <Thermoplastic polyimide> Thermoplastic polyimides (hereinafter sometimes referred to as "TPI") are obtained by polymerizing a tetracarboxylic acid component and a diamine component. The thermoplastic polyimide preferably has a repeating unit derived from a tetracarboxylic acid component (a-1) and a repeating unit derived from an aliphatic diamine component (a-2).

[0050] Examples of the tetracarboxylic acid component (a-1) constituting the thermoplastic polyimide include alicyclic tetracarboxylic acids such as cyclobutane-1,2,3,4-tetracarboxylic acid, cyclopentane-1,2,3,4-tetracarboxylic acid, and cyclohexane-1,2,4,5-tetracarboxylic acid, 3,3',4,4'-diphenylsulfonetetracarboxylic acid, 3,3',4,4'-benzophenonetetracarboxylic acid, biphenyltetracarboxylic acid, naphthalene-1,4,5,8-tetracarboxylic acid, and pyromellitic acid. In addition, alkyl esters of these compounds can be used in the polymerization of the thermoplastic polyimide.

[0051] In particular, it is preferable that more than 50 mol% of the tetracarboxylic acid component (a-1) is pyromellitic acid. When the tetracarboxylic acid component (a-1) is mainly composed of pyromellitic acid, the resin film tends to exhibit excellent heat resistance and secondary processability. The content of pyromellitic acid in the tetracarboxylic acid component (a-1) is more preferably 60 mol% or more, even more preferably 80 mol% or more, and particularly preferably 90 mol% or more, and it is particularly preferable that all (100 mol%) of the tetracarboxylic acid component (a-1) is pyromellitic acid.

[0052] The diamine components constituting the thermoplastic polyimide preferably contain aliphatic diamine (a-2) as the main component. That is, it is preferable that more than 50 mol% of the diamine components are aliphatic diamine (a-2), more preferably 60 mol% or more, even more preferably 80 mol% or more, and particularly preferably 90 mol% or more, and it is particularly preferable that all (100 mol%) of the diamine components are aliphatic diamine (a-2). This makes it easier for the resin film to exhibit excellent heat resistance and secondary processability. In this specification, aliphatic diamines also include alicyclic diamines.

[0053] The aliphatic diamine (a-2) is not particularly limited as long as it is a diamine component having amino groups at both ends of a hydrocarbon group, and examples thereof include alicyclic diamines, linear aliphatic diamines, and branched aliphatic diamines. When heat resistance, heat aging resistance, and the like are important, the aliphatic diamine (a-2) preferably contains an alicyclic diamine. The alicyclic diamine may have amino groups bonded to both ends of the cyclic hydrocarbon (i.e., carbon atoms that constitute the ring but are not adjacent to each other), or may have amino groups bonded to a carbon atom of the cyclic hydrocarbon and to the end of the hydrocarbon bonded to the cyclic hydrocarbon, or may have amino groups bonded to the ends of each of the two hydrocarbons bonded to the cyclic hydrocarbon. Specific examples of alicyclic diamines include 1,3-bis(aminomethyl)cyclohexane, 1,4-bis(aminomethyl)cyclohexane, 4,4'-diaminodicyclohexylmethane, 4,4'-methylenebis(2-methylcyclohexylamine), isophoronediamine, norbornanediamine, bis(aminomethyl)tricyclodecane, etc. Among these, 1,3-bis(aminomethyl)cyclohexane is preferably used from the viewpoints of heat resistance, heat aging resistance, moldability, secondary processability, etc.

[0054] On the other hand, when toughness, moldability, and secondary processability are important, it is preferable that the aliphatic diamine (a-2) contains at least one of a linear aliphatic diamine and a branched aliphatic diamine. The linear aliphatic diamine and the branched aliphatic diamine preferably have amino groups at both ends of the linear hydrocarbon chain and at both ends of the branched hydrocarbon chain. The linear aliphatic diamine is not particularly limited as long as it is a diamine component having amine groups at both ends of an alkyl group, and specific examples include ethylenediamine (carbon number 2), propylenediamine (carbon number 3), butanediamine (carbon number 4), pentanediamine (carbon number 5), hexanediamine (carbon number 6), heptanediamine (carbon number 7), octanediamine (carbon number 8), nonanediamine (carbon number 9), decanediamine (carbon number 10), undecanediamine (carbon number 11), and dodecanediamine (carbon number 12). Examples of such diamines include linear aliphatic diamines having approximately 2 to 50 carbon atoms, such as tridecanediamine (13 carbon atoms), tetradecanediamine (14 carbon atoms), pentadecanediamine (15 carbon atoms), hexadecanediamine (16 carbon atoms), heptadecanediamine (17 carbon atoms), octadecanediamine (18 carbon atoms), nonadecanediamine (19 carbon atoms), eicosanediamine (20 carbon atoms), triacontanediamine (30 carbon atoms), tetracontanediamine (40 carbon atoms), and pentacontanediamine (50 carbon atoms). Among these, from the viewpoints of excellent moldability, secondary processability, and low moisture absorption, linear aliphatic diamines having 4 to 20 carbon atoms are preferred, linear aliphatic diamines having 5 to 16 carbon atoms are more preferred, and linear aliphatic diamines having 6 to 12 carbon atoms are even more preferred. Examples of the branched aliphatic diamine include those obtained by bonding a branched structure having preferably 1 to 20 carbon atoms, more preferably 1 to 10 carbon atoms, to these linear aliphatic diamines. From the viewpoint of crystallinity, it is particularly preferable that the aliphatic diamine (a-2) contains a linear aliphatic diamine.

[0055] The thermoplastic polyimide may contain a structural unit derived from a diamine component other than the aliphatic diamine (a-2). Specific examples of the other diamine component include 1,4-phenylenediamine, 1,3-phenylenediamine, 2,4-toluenediamine, 4,4'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 4,4'-diaminodiphenylmethane, 1,4-bis(4-aminophenoxy)benzene, 1,3-bis(4-aminophenoxy)benzene, 1,3-bis(3-aminophenoxy)benzene, α,α'-bis(4-aminophenyl)-1,4'-diisopropylbenzene, α,α'-bis(3-aminophenyl)-1,4-diisopropylbenzene, 2,2-bis[4-(4-aminophenoxy)phenyl]propane, 4,4'-diaminodiphenylmethane, 1,4-bis(4-aminophenoxy)benzene, 1,3-bis(4-aminophenoxy)benzene, 1,3-bis(3-aminophenoxy)benzene, α,α'-bis(4-aminophenyl)-1,4-diisopropylbenzene, α,α'-bis(3-aminophenyl)-1,4-diisopropylbenzene, 2,2-bis[4-(4-aminophenoxy)phenyl]propane, 4,4'-diaminodiphenylmethane, 1,4-bis(4-aminophenoxy)benzene, 1,3-bis(4-aminophenoxy)benzene, 1,3-bis(4-aminophenoxy)benzene, α,α'-bis(4-aminophenyl)-1,4-diisopropylbenzene, 2,2-bis[4-(4-aminophenoxy)phenyl]propane, 4,4'-diaminodiphenylmethane, 1,4-bis(4-aminophenoxy)benzene, 1,3-bis(4-aminophenoxy)benzene, 1,3-bis(4-aminophenoxy)benzene, α,α Examples of the diamine component include aromatic diamine components such as aminodiphenyl sulfone, bis[4-(4-aminophenoxy)phenyl]sulfone, bis[4-(3-aminophenoxy)phenyl]sulfone, 2,6-diaminonaphthalene, 1,5-diaminonaphthalene, p-xylylenediamine, and m-xylylenediamine; ether diamine components such as polyethylene glycol bis(3-aminopropyl) ether and polypropylene glycol bis(3-aminopropyl) ether; and siloxane diamines.

[0056] The aliphatic diamine (a-2) may contain at least one of a linear aliphatic diamine and a branched aliphatic diamine, or an alicyclic diamine, or both. However, from the viewpoint of achieving a good balance of various performances, it preferably contains at least one of a linear aliphatic diamine and a branched aliphatic diamine, and an alicyclic diamine, and more preferably contains both a linear aliphatic diamine and an alicyclic diamine. When both a linear aliphatic diamine and a branched aliphatic diamine and an alicyclic diamine are contained, the content ratio, on a molar basis, of the linear aliphatic diamine and / or the branched aliphatic diamine to the alicyclic diamine is preferably in the range of 1:99 to 90:10, more preferably 1:99 to 80:20, even more preferably 1:99 to 70:30, particularly preferably 10:90 to 70:30, particularly preferably 20:80 to 70:30, and most preferably 25:75 to 60:40. When the ratio of the linear aliphatic diamine and / or the branched aliphatic diamine to the alicyclic diamine contained in the aliphatic diamine (a-2) is in this range, the balance of heat resistance, heat aging resistance, toughness, moldability, etc. is likely to be excellent.

[0057] The thermoplastic polyimide preferably has crystallinity. Crystalline thermoplastic polyimides exhibit a crystalline melting peak in differential scanning calorimetry (DSC) measurements. The specific crystalline melting temperature of the thermoplastic polyimide is preferably 260 to 350°C, more preferably 270 to 345°C, and even more preferably 280 to 340°C. If the crystalline melting temperature of the thermoplastic polyimide is equal to or higher than the lower limit, the insulating film is likely to have sufficient heat resistance. On the other hand, if the crystalline melting temperature is equal to or lower than the upper limit, molding or secondary processing can be easily performed at a relatively low temperature, which is preferable.

[0058] The glass transition temperature of the thermoplastic polyimide is preferably 150°C or higher, more preferably 160°C or higher, even more preferably 170°C or higher, even more preferably 175°C or higher, and particularly preferably 180°C or higher. The glass transition temperature of the thermoplastic polyimide is preferably 300°C or lower, more preferably 280°C or lower, even more preferably 260°C or lower, even more preferably 250°C or lower, and particularly preferably 240°C or lower. If the glass transition temperature of the thermoplastic polyimide is equal to or higher than the lower limit, the resin film is likely to have sufficient heat resistance. On the other hand, if the glass transition temperature is equal to or lower than the upper limit, molding at a relatively low temperature is easy, which is preferable.

[0059] The tensile modulus of the thermoplastic polyimide is preferably 1.0 GPa or more, more preferably 1.2 GPa or more, and even more preferably 1.5 GPa or more, and is preferably 10 GPa or less, more preferably 8 GPa or less, and even more preferably 6 GPa or less.

[0060] <Aromatic polyamide> The aromatic polyamide (hereinafter sometimes referred to as "aromatic PA") may be a wholly aromatic polyamide obtained by polymerizing an aromatic dicarboxylic acid and an aromatic diamine, or a polyamide resin (semi-aromatic polyamide) obtained by polymerizing a linear aliphatic dicarboxylic acid component or a linear aliphatic diamine component having 10 to 12 carbon atoms and a diamine component or dicarboxylic acid component having an aromatic ring as the main components. Among these, it is preferable to use a semi-aromatic polyamide that exhibits thermoplasticity that provides good thermal adhesion to aramid paper. Among these, the aromatic polyamide is more preferably a polyamide resin (semi-aromatic polyamide) obtained by polymerizing a linear aliphatic dicarboxylic acid component or a linear aliphatic diamine component having 10 to 12 carbon atoms and a diamine component or dicarboxylic acid component having an aromatic ring as the main components.

[0061] The content of linear aliphatic dicarboxylic acid units constituting the semi-aromatic polyamide is 60 mol% or more, preferably 80 mol% or more, more preferably 90 mol% or more, and even more preferably 100 mol% of all dicarboxylic acid units. All of the dicarboxylic acid components may be one or more selected from the group consisting of 1,8-octanedicarboxylic acid, 1,9-nonanedicarboxylic acid, and 1,10-decanedicarboxylic acid. By using a linear aliphatic dicarboxylic acid having from 10 to 12 carbon atoms, it becomes easier to obtain a semi-aromatic polyamide having excellent heat resistance, etc.

[0062] The content of linear aliphatic diamine units constituting the semi-aromatic polyamide is 60 mol% or more, preferably 80 mol% or more, more preferably 90 mol% or more, and even more preferably 100 mol% of all diamine units. All of the diamine components may be one or more selected from the group consisting of 1,10-decanediamine, 1,11-undecanediamine, and 1,12-dodecanediamine. By using a linear aliphatic diamine having 10 to 12 carbon atoms, it becomes easier to obtain a semi-aromatic polyamide with excellent heat resistance, etc.

[0063] The content of aromatic dicarboxylic acid units constituting the semi-aromatic polyamide is 60 mol% or more, preferably 80 mol% or more, more preferably 90 mol% or more, and even more preferably 100 mol% based on the total dicarboxylic acid units. All of the dicarboxylic acid components may be terephthalic acid and / or isophthalic acid. By using terephthalic acid and / or isophthalic acid as the aromatic dicarboxylic acid, it becomes easier to obtain a semi-aromatic polyamide having excellent heat resistance, etc.

[0064] The content of aromatic diamine units constituting the semi-aromatic polyamide is 60 mol% or more, preferably 80 mol% or more, more preferably 90 mol% or more, and even more preferably 100 mol% of all diamine units. All of the diamine components may be paraxylylenediamine and / or metaxylylenediamine. By using paraxylylenediamine and / or metaxylylenediamine as the aromatic diamine, it becomes easier to obtain a semi-aromatic polyamide having excellent heat resistance, etc.

[0065] Specific examples of aromatic polyamides include polyamide 4T (PA4T; manufactured by DSM Engineering Plastics, etc.), polyamide 6T (PA6T; manufactured by Mitsui Chemicals, etc.), polyamide MXD6 (PAMXD6; manufactured by Mitsubishi Gas Chemical, etc.), polyamide 9T (PA9T; manufactured by Kuraray, etc.), polyamide 10T (PA10T; manufactured by Unitika, Daicel-Evonik, etc.), polyamide 11T (PA11T; manufactured by Toyobo, etc.), polyamide 12T (PA12T; manufactured by Henan Junheng, etc.), and polyamide 13T (PA13T).

[0066] The glass transition temperature Tg of the aromatic polyamide is preferably 100° C. or higher, more preferably 110° C. or higher, and even more preferably 120° C. or higher. The glass transition temperature Tg of the aromatic polyamide is preferably 200° C. or lower, more preferably 180° C. or lower, and even more preferably 160° C. or lower.

[0067] The melting point (crystalline melting temperature) Tm of the aromatic polyamide is preferably 260° C. or higher, more preferably 280° C. or higher, and even more preferably 300° C. or higher. The melting point (crystalline melting temperature) Tm of the aromatic polyamide is preferably 350° C. or lower, more preferably 340° C. or lower, and even more preferably 330° C. or lower. If the melting point of the aromatic polyamide is within the above range, heat resistance can be improved while moldability (fluidity) can be ensured, and decomposition does not occur during molding, ensuring safety during production.

[0068] <Aromatic polyester> The aromatic polyester refers to a polyester resin having an aromatic group in at least one of the polycarboxylic acid unit and the polyhydric alcohol unit constituting the polyester. The aromatic polyester may be a homopolyester or a copolymer polyester.

[0069] The homopolyester is preferably one obtained by polycondensation of an aromatic dicarboxylic acid and an aliphatic glycol. Examples of aromatic dicarboxylic acids include terephthalic acid and 2,6-naphthalenedicarboxylic acid, and examples of aliphatic glycols include ethylene glycol, diethylene glycol, 1,4-butanediol, and 1,4-cyclohexanedimethanol. Representative examples of homopolyesters include polyethylene terephthalate (PET), polybutylene terephthalate (PBT), and polyethylene-2,6-naphthalate (PEN). In this embodiment, PET and PEN are preferred because of their excellent durability, and PET is more preferred from the viewpoint of versatility.

[0070] On the other hand, examples of the dicarboxylic acid component of the copolymer polyester include one or more of isophthalic acid, phthalic acid, terephthalic acid, 2,6-naphthalenedicarboxylic acid, adipic acid, sebacic acid, etc., and examples of the glycol component include one or more of ethylene glycol, diethylene glycol, propylene glycol, butanediol, 4-cyclohexanedimethanol, neopentyl glycol, etc. The copolymer polyester contains an aromatic compound in the dicarboxylic acid component and / or the glycol component.

[0071] When the aromatic polyester is a copolymer polyester, it is preferably a copolymer containing 30 mol% or less of a third component, more preferably 60 mol% or more, preferably 80 mol% or more of ethylene terephthalate units or ethylene-2,6-naphthalate units, and from the viewpoint of versatility, it is even more preferably 60 mol% or more, preferably 80 mol% or more of ethylene terephthalate units.

[0072] The polyester polymerization catalyst is not particularly limited, and a conventionally known compound can be used, for example, a titanium compound, a germanium compound, an antimony compound, a manganese compound, an aluminum compound, a magnesium compound, a calcium compound, etc. Among these, at least one of a titanium compound and an antimony compound is preferred.

[0073] In order to suppress the amount of precipitation of oligomer components, the film may be produced using a polyester having a low content of oligomer components as the raw material. As a method for producing a polyester having a low content of oligomer components, various known methods can be used, such as a method in which solid-state polymerization is carried out after the polyester is produced.

[0074] <Polycarbonate> Polycarbonate (hereinafter sometimes referred to as "PC") is obtained by polymerizing bisphenols with phosgene or diphenyl carbonate. Widely used inexpensive polymerization methods include the interfacial method (interfacial polycondensation method), in which bisphenols and phosgene are reacted in solution, the solution method, and the melt method, in which bisphenols and carbonate diesters are polycondensed via transesterification. The following compounds are suitable for use as bisphenols. Polycarbonates can be made not only from homopolymers of one type of bisphenol, but also from copolymers produced by copolymerizing two or more types of bisphenols.

[0075] [ka]

[0076] Of the above, polycarbonates having a structural unit represented by the following formula (6) are preferred.

[0077] [ka]

[0078] In formula (6), substituent R 1 and R 2 each independently represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, and the substituents may be bonded to form a ring. 3 and R 4 each independently represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, and j and k represent 0 to 4. W represents a single bond, an oxygen atom, -CR 5 R 6 -, and the substituent R 5 and R 6 each independently represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or a phenyl group, provided that the units t and u have different structures.

[0079] The number of carbon atoms in the alkyl group is preferably 6 or less, more preferably 4 or less, and particularly preferably 3 or less. Specific examples of the alkyl group include linear alkyl groups such as methyl, ethyl, and propyl groups; branched alkyl groups such as isopropyl, tert-butyl, and isobutyl groups; and cyclic alkyl groups such as cyclohexyl and cyclopentyl groups. Among these, a methyl group is particularly preferred from the viewpoint of synthesis. Furthermore, the substituents may be bonded to each other to form a ring.

[0080] The number of carbon atoms in the aryl group is preferably 30 or less, more preferably 20 or less, and particularly preferably 15 or less. Specific examples include a phenyl group, a naphthyl group, an anthranyl group, and a pyrenyl group.

[0081] Specific examples of suitable structural units of polycarbonate are shown below, but polycarbonate is not limited to these.

[0082] [ka]

[0083] The viscosity average molecular weight of the polycarbonate is preferably 10,000 or more, more preferably 20,000 or more. The viscosity average molecular weight of the polycarbonate is preferably 150,000 or less, more preferably 120,000 or less, and even more preferably 100,000 or less. By setting the viscosity average molecular weight within the above range, a resin film having sufficient heat resistance can be easily obtained.

[0084] <Polyaryletherketone> Polyaryletherketone (hereinafter sometimes referred to as "PAEK") is a crystalline resin containing an arylene group, an ether group, and a carbonyl group. Specific examples include polyetheretherketone (PEEK) resin represented by structural formula (7), polyetherketone (PEK) resin represented by structural formula (8), polyetherketoneketone (PEKK) resin represented by structural formula (9), polyetheretherketoneketone (PEEKK) resin represented by structural formula (10), and polyetherketoneetherketoneketone (PEKEKK) resin represented by structural formula (11).

[0085] [ka]

[0086] [ka]

[0087] [ka]

[0088] [ka]

[0089] [ka]

[0090] Among the above polyaryletherketones, polyetheretherketone (PEEK) and polyetherketone (PEK) are preferred from the viewpoints of availability, production cost, and moldability, with polyetheretherketone (PEEK) being particularly preferred. One type of polyaryletherketone may be used alone, or two or more types may be mixed and used. Furthermore, the polyaryletherketone may be a copolymer having two or more of the chemical structures shown in the above (7) to (11).

[0091] The glass transition temperature Tg of the polyaryl ether ketone is preferably 100° C. or higher, more preferably 120° C. or higher, and even more preferably 140° C. or higher. The glass transition temperature Tg of the polyaryl ether ketone is preferably 200° C. or lower, more preferably 190° C. or lower, and even more preferably 180° C. or lower.

[0092] The melting point (crystalline melting temperature) Tm of the polyaryl ether ketone is preferably 300° C. or higher, more preferably 310° C. or higher, and even more preferably 320° C. or higher. The melting point (crystalline melting temperature) Tm of the polyaryl ether ketone is preferably 400° C. or lower, more preferably 380° C. or lower, and even more preferably 360° C. or lower. If the melting point of the polyaryl ether ketone is within the above range, heat resistance can be improved while moldability (fluidity) can be ensured, and decomposition does not occur during molding, ensuring safety during production.

[0093] The tensile modulus of the polyaryletherketone is preferably 2.0 GPa or more, more preferably 2.3 GPa or more, and even more preferably 2.5 GPa or more, and the tensile modulus of the polyaryletherketone is preferably 10.0 GPa or less, more preferably 8.0 GPa or less, and even more preferably 6.0 GPa or less.

[0094] (Inorganic filler) The insulating film contains an inorganic filler. Examples of inorganic fillers include titanium oxide, zinc oxide, alumina, aluminum nitride, boron nitride, boehmite, potassium titanate, calcium titanate, wollastonite, silica, mica, sericite, illite, talc, kaolinite, montmorillonite, smectite, vermiculite, boehmite, and alumina. Among these, the inorganic filler is preferably at least one selected from the group consisting of titanium oxide, zinc oxide, alumina, aluminum nitride, boron nitride, boehmite, potassium titanate, calcium titanate, and wollastonite, more preferably at least one selected from the group consisting of titanium oxide, zinc oxide, alumina, aluminum nitride, boron nitride, boehmite, potassium titanate, and calcium titanate, and particularly preferably titanium oxide. One type of inorganic filler may be used alone, or two or more types may be used in combination.

[0095] The inorganic filler used in this embodiment is preferably acicular (including fibrous). In this specification, the aspect ratio (value of average major axis length / average minor axis length) of the acicular inorganic filler is preferably 2 or more, more preferably 5 or more, and even more preferably 10 or more. In addition, there is no particular upper limit to the aspect ratio (value of average major axis length / average minor axis length) of the acicular inorganic filler, but it is preferably 100 or less, more preferably 80 or less, and even more preferably 50 or less.

[0096] The average major axis length (average major axis diameter) of the inorganic filler is preferably 0.5 μm or more, more preferably 1 μm or more, even more preferably 1.5 μm or more, even more preferably 2.0 μm or more, and even more preferably 2.5 μm or more. The average major axis length of the inorganic filler is preferably 10 μm or less.

[0097] The average minor axis length (average minor axis diameter) of the inorganic filler is preferably 1.0 μm or less, more preferably 0.8 μm or less, even more preferably 0.5 μm or less, even more preferably 0.4 μm or less, and even more preferably 0.3 μm or less. The average minor axis length of the inorganic filler is preferably 0.01 μm or more.

[0098] In this embodiment, a needle-shaped inorganic filler is used. Furthermore, by setting the average major axis length (average major axis diameter), average minor axis length (average minor axis diameter), and aspect ratio of the inorganic filler within the above-described ranges, the inorganic filler can be oriented in one direction within the insulating film. This allows the tensile modulus of elasticity (E'1) in the first direction divided by the tensile modulus of elasticity (E'2) in the second direction perpendicular to the first direction (E'1 / E'2) to be equal to or greater than a predetermined value. This increases the compressive strength in the direction in which the inorganic filler is oriented (the long axis direction of the inorganic filler), thereby effectively improving buckling resistance. Furthermore, by unidirectionally orienting the inorganic filler within the insulating film, fracture of the inorganic filler can be suppressed when the insulating film is bent parallel to the direction in which the inorganic filler is oriented (the long axis direction of the inorganic filler), thereby suppressing breakage or cracking of the film.

[0099] The content of the inorganic filler in the insulating film is preferably 5% by mass or more, more preferably 10% by mass or more, even more preferably 15% by mass or more, and even more preferably 20% by mass or more, based on the total mass of the insulating film. The content of the inorganic filler in the insulating film is preferably 70% by mass or less, more preferably 60% by mass or less, and even more preferably 50% by mass or less, based on the total mass of the insulating film.

[0100] The inorganic filler may be modified with a surface treatment agent to improve dispersibility in the resin. The method of surface modification is not particularly limited, but for example, surface modification using a silane coupling agent can be performed.

[0101] <Optional ingredients> The insulating film may contain various additives such as heat stabilizers, antioxidants, ultraviolet absorbers, light stabilizers, antibacterial and antifungal agents, antistatic agents, lubricants, pigments, and dyes, as long as the effects of the present invention are not impaired.

[0102] (Method of manufacturing insulating film for motors) The insulating film is produced, for example, by kneading a resin and an inorganic filler and molding the mixture into a film. The resin is preferably a thermoplastic resin, since this makes it easier to obtain a film in which the inorganic filler is oriented in one direction during molding. The method for producing an insulating film for motors preferably includes kneading a resin and an inorganic filler having an aspect ratio of 5 to 100 and molding the mixture into a film.

[0103] The inorganic filler used in the method for producing an insulating film for motors is preferably at least one selected from the group consisting of titanium oxide, zinc oxide, alumina, aluminum nitride, boron nitride, boehmite, potassium titanate, and calcium titanate. The aspect ratio (average major axis length / average minor axis length) of the inorganic filler used in the method for producing an insulating film for motors is preferably 2 or more, more preferably 5 or more, and even more preferably 10 or more. The aspect ratio (average major axis length / average minor axis length) of the inorganic filler is preferably 100 or less, more preferably 80 or less, and even more preferably 50 or less.

[0104] The resin used in the method for producing the insulating film of the present invention is the same as the resin described above, and the preferred type of resin, the preferred glass transition temperature and tensile modulus of the resin are the same as those described above.

[0105] The method for producing the insulating film includes a step of forming a resin composition obtained by kneading a resin and an inorganic filler into a film using a common molding method. Examples of molding methods that can be used include extrusion molding, calendar molding, solution casting, injection molding, blow molding, vacuum molding, pressure molding, and press molding. While the apparatus and processing conditions for each molding method are not particularly limited, extrusion molding, particularly the T-die method, is preferred from the viewpoints of productivity and thickness control.

[0106] The method for producing the insulating film is not particularly limited, but it is preferable to form a resin composition obtained by kneading a resin and an inorganic filler into a film shape to form a non-stretched or stretched film. From the viewpoint of secondary processability, the insulating film is preferably a non-stretched film. Note that a non-stretched film is a film that is not actively stretched for the purpose of controlling the sheet orientation, and also includes a film that is oriented when taken up by a cast roll using the T-die method.

[0107] In the case of an unstretched film, for example, it can be produced by melt-kneading a resin and an inorganic filler, followed by extrusion molding and cooling. A known kneader such as a single-screw or twin-screw extruder can be used for melt-kneading. Molding can be performed, for example, by extrusion molding using a mold such as a T-die. In this embodiment, the inorganic filler can be oriented in one direction by extrusion molding a resin composition obtained by kneading a resin and an inorganic filler.

[0108] The MFR (5 kg) at the molding temperature of the resin composition obtained by melt-kneading the resin and inorganic filler is preferably 1 g / 10 min or more, more preferably 3 g / 10 min or more, and even more preferably 5 g / 10 min or more. The MFR (5 kg) at the molding temperature of the resin composition is preferably 50 g / min or less, more preferably 45 g / min or less, and even more preferably 40 g / min or less.

[0109] The kneading conditions when melt-kneading the resin and inorganic filler can be adjusted appropriately depending on the type of resin and the size of the extruder, but for example, the screw rotation speed can be set to 10 rpm or more and less than 300 rpm.

[0110] The insulating film may be a laminated film. When producing a laminated film, the lamination method is not particularly limited, and may be, for example, a coextrusion method in which the constituent materials of each layer are coextruded and laminated, an extrusion lamination method in which each layer is formed into a film and then laminated, or a thermocompression bonding method in which each layer is formed into a film and then thermocompression bonded. However, from the viewpoint of productivity, the coextrusion method is preferred. Coextrusion methods include a multi-manifold method in which the constituent materials of each layer are joined at a die, and a feedblock method in which the materials are joined at a feedblock, and any of these may be used.

[0111] The insulating film may be subjected to a surface treatment, such as a plasma treatment or a corona treatment.

[0112] (Laminated insulating film for motors) This embodiment may relate to a laminated insulating film for motors (hereinafter, sometimes referred to as "the present laminated insulating film") that has aramid paper on at least one side of the above-mentioned insulating paper for motors. The present insulating film may be composed of only a resin layer, but aramid paper may also be laminated on it if necessary.

[0113] Aramid is a linear polymeric compound in which 60% or more of the amide bonds are directly bonded to aromatic rings. Examples of aramid include polymetaphenylene isophthalamide and its copolymers, polyparaphenylene terephthalamide and its copolymers, and copolyparaphenylene 3,4'-diphenyl ether terephthalamide.

[0114] The thickness of the aramid paper in the present laminated insulating film is preferably 1 μm or more, more preferably 3 μm or more, and even more preferably 5 μm or more, and is preferably 400 μm or less, more preferably 300 μm or less, even more preferably 200 μm or less, and particularly preferably 150 μm or less.

[0115] The basis weight of the aramid paper in this laminated insulating film is 10 g / m 2 It is preferable that the content is 15 g / m or more. 2 More preferably, it is 20 g / m or more. 2 The basis weight of the aramid paper is more preferably 1000 g / m or more. 2 It is preferable that the weight is 900 g / m or more. 2 More preferably, it is 800 g / m or more. 2 More preferably, it is equal to or greater than this.

[0116] The aramid paper is preferably a sheet-like product made by papermaking aramid staple fibers. The fineness of the aramid staple fibers is preferably 0.05 dtex or more and less than 25 dtex. By setting the fineness of the aramid staple fibers within the above range, aggregation can be suppressed when the aramid paper is produced by a wet papermaking method, making it easier to obtain uniform aramid paper.

[0117] The length of the aramid short fibers is preferably 1 mm or more and less than 25 mm. By setting the length of the aramid short fibers within the above range, the mechanical properties of the aramid paper can be improved, and the production efficiency when the aramid paper is produced by a wet papermaking method can be increased.

[0118] The aramid paper may contain aramid fibrids in addition to aramid short fibers. Aramid fibrids are film-like fine particles made of aramid, and are produced by methods described in, for example, Japanese Patent Publication Nos. 11851 / 1960 and 5732 / 1962.

[0119] Aramid paper is produced, for example, by mixing aramid staple fibers and aramid fibrids and then forming them into a sheet. For example, there is a method (airlaid method) in which aramid staple fibers and aramid fibrids are dry-blended, and then deposited into a sheet using an airflow to form a sheet, and there is a method in which aramid staple fibers and aramid fibrids are dispersed and mixed in a liquid medium to form a slurry, and then the slurry is wet-laid papermaking. In the wet papermaking method, an aqueous slurry containing at least aramid fibrids and aramid staple fibers is sent to a papermaking machine and dispersed, and then dehydrated, squeezed, and dried to form a sheet. As the papermaking machine, a Fourdrinier papermaking machine, a cylinder papermaking machine, an inclined papermaking machine, or a combination papermaking machine combining these may be used. Additives such as a dispersibility improver, an antifoaming agent, and a paper strength enhancer may be added to the slurry as needed.

[0120] Before the step of forming the aramid paper, the aramid short fibers and / or aramid fibrids may be subjected to a beating treatment. By performing the beating treatment, the specific surface area of ​​the aramid and / or aramid fibrids can be increased, and the strength of the aramid paper can be effectively increased.

[0121] After the step of forming the aramid paper, a calendering treatment may be carried out as necessary. In the calendering treatment, the aramid paper is subjected to a heat and pressure treatment at high temperature and pressure between a pair of rolls. This can improve the smoothness of the aramid paper, as well as its density and mechanical strength.

[0122] The method for manufacturing a laminated insulating film for motors includes a step of laminating the above-mentioned motor insulating paper (resin film) and aramid paper. Methods for laminating the aramid paper and resin film include heating, pressure processing, and a heating and pressure processing method (hot press method). In this embodiment, a step of preheating the resin film may be provided as necessary before laminating the aramid paper and resin film and subjecting them to heating and / or pressure processing. In the preheating step, the resin film is preheated using, for example, a roll heater or an infrared heater. The heating temperature is preferably set to a temperature equal to or lower than the softening temperature of the resin.

[0123] (Application) This insulating film is used in motors for home appliances, audio equipment, IT equipment, communications equipment, office automation equipment, medical equipment, healthcare equipment, business equipment, industrial equipment, and transportation equipment such as automobiles, railways, and ships. For example, it is used for insulation between coil bundles and layers in motors, or for insulation between coils and stators. This insulating film is particularly suitable for insulation between coils and stators, and is suitable as wedge paper or slot paper, especially slot paper. The slot paper is inserted so that it fits along the inner circumferential surface of the slot (groove) in the motor stator. The insertion direction of the slot paper is preferably the same as the orientation direction of the needle-shaped inorganic filler. This insulating film is resistant to deformation and cracking when inserted into the slot, allowing it to be used without problems of poor insulation.

[0124] The present embodiment may relate to a motor including the insulating film for a motor or the laminated insulating film for a motor. The insulating film can be thinned while preventing buckling when the insulating film is inserted into the motor and preventing breakage or cracking when the film is folded, and therefore is preferably used for small, high-output motors. [Example]

[0125] The features of the present invention will be explained in more detail below with reference to examples and comparative examples. The materials, amounts used, ratios, treatment contents, treatment procedures, etc. shown in the following examples can be changed as appropriate without departing from the spirit of the present invention. Therefore, the scope of the present invention should not be construed as being limited by the specific examples shown below.

[0126] (1) Particle size of inorganic filler The particle size, major axis length, and minor axis length of the inorganic filler were determined by observing the inorganic filler under an electron microscope. At least 100 particles of the inorganic filler were randomly selected and the average particle size, major axis length, and minor axis length of the particles were calculated.

[0127] (2) Glass transition temperature and crystalline melting temperature of resin The glass transition temperature and crystalline melting temperature of the resin were measured in accordance with JIS K7121:2012. A differential scanning calorimeter, Pyris1 DSC (manufactured by PerkinElmer), was used for the measurements. The glass transition temperature and crystalline melting temperature of the resin were determined from the inflection point and endothermic peak top temperature of the DSC curve of the resin pellets detected during the reheating process in the temperature range of 25 to 380°C at a heating rate of 10°C / min.

[0128] (3) Tensile modulus The tensile modulus of the resin was measured at a temperature of 23°C in accordance with ISO527 using a sample obtained by injection molding the resin pellets. The tensile modulus of elasticity in the machine direction (MD) and transverse direction (TD) of the insulating film was measured at a temperature of 23°C in accordance with JIS K7127:1999.

[0129] (4) Compressive strength The resulting 200 μm-thick insulating film was punched out using a punching blade with a width of 12.7 mm (longitudinal) and a length of 157 mm (transverse). The film was then rolled lengthwise to form a longitudinal (MD) test specimen. Next, a test specimen holder consisting of a block (outer frame) with a cylindrical recess (inner diameter 49.8 mm, depth 6.35 mm) and a removable disk (inner frame) (outer diameter 49.3 mm) was used. The disk was attached to the block, and the test specimen was clamped in the circular groove formed by the disk. If the edges of the test specimen placed in the groove of the test specimen holder overlapped, the excess length was trimmed. After placing the test specimen in the test specimen holder, the precision universal testing machine Autograph AGS-X (Shimadzu Corporation) was used to operate the test specimen until it was crushed. The maximum compressive force at the time of crushing was measured, and this was taken as the compressive strength. Compression strength of 800N or more was rated A (good buckling resistance), and compression strength of less than 800N was rated B (poor buckling resistance).

[0130] (5) 180° bending test The obtained insulating film was cut into a 10 cm square and folded 180° along the machine direction (MD). Three trials were performed, and if no cracks occurred in the film in any of the three trials, it was rated as A, and if cracks occurred in the film at least once, it was rated as B.

[0131] The following materials were used as constituent materials of the insulating film for motors.

[0132] Resin (A) (A)-1: Polyether ether ketone (VESTAKEEP 3300G, manufactured by Daicel Evonik, glass transition temperature: 145°C, crystalline melting temperature: 338°C, MVR (380°C, 5 kgf) = 20 cm 3 / 10min, tensile modulus 3.6GPa) (A)-2: Polyetherimide (Sabic Ultem CRS5001, glass transition temperature: 225°C, MVR (380°C, 5 kgf) = 7 cm 3 / 10min), tensile modulus 3.2GPa)

[0133] [Inorganic filler (B)] (B)-1: Needle filler (FTL-200 manufactured by Ishihara Sangyo Kaisha (material: titanium oxide), average major axis length: 3 μm, average minor axis length: 0.2 μm, aspect ratio: 14) (B)-2: Acicular filler (FTL-300 manufactured by Ishihara Sangyo Kaisha (material: titanium oxide), average major axis length: 5 μm, average minor axis length: 0.3 μm, aspect ratio: 19) (B)-3: Plate-like filler (Topy Industries PDM-5L (material: synthetic mica), average major axis length: 5 μm, average minor axis length: 0.1 μm, aspect ratio 50) (B)-4: Spherical filler (Denka GT130MC (material: fused silica) average particle size: 0.6 μm, aspect ratio: 1)

[0134] Example 1 A mixed composition prepared by mixing (A)-1 and (B)-1 in the mass ratio shown in Table 1 was kneaded using a Φ40 mm co-rotating single-screw extruder equipped with a T-die at a kneading temperature of 380°C and a screw rotation speed of 30 rpm. The mixture was then extruded from the T-die and cooled on a casting roll at a temperature of 210°C to prepare an insulating film (sample) with a thickness of 200 μm.

[0135] Examples 2 to 5 An insulating film (sample) having a thickness of 200 μm was produced in the same manner as in Example 1, except that the mixing mass ratio of (A)-1, (A)-2, (B)-1, and (B)-2 was changed as shown in Table 1.

[0136] (Comparative Examples 1 to 4) An insulating film (sample) having a thickness of 200 μm was produced in the same manner as in Example 1, except that the mixing mass ratio of (A)-1, (A)-2, (B)-3, and (B)-4 was changed as shown in Table 1.

[0137] [Table 1]

[0138] From the results of the examples in the table above, it can be inferred that the insulating film containing acicular inorganic filler has a high tensile modulus in the machine direction (MD) / transverse direction (TD), and that the inorganic filler is oriented in the machine direction (MD) within the film. This increases the compressive strength of the film in the machine direction (MD), and it can be bent 180° along the machine direction (MD), demonstrating good bending processability.

[0139] On the other hand, when a plate-like inorganic filler was blended as in Comparative Example 1, the elastic modulus in the machine direction (MD) / transverse direction (TD) was low, and the inorganic filler was not oriented, resulting in an insufficient increase in compressive strength. Furthermore, when the film was bent 180°, cracks occurred. Even when spherical inorganic fillers were blended as in Comparative Example 2, the machine direction (MD) / cross direction (TD) values ​​were low and 180° bending was possible, but the increase in compressive strength was slight because the inorganic filler was not oriented. When no inorganic filler was included as in Comparative Examples 3 and 4, the compressive strength was low.

Claims

1. Contains resin and inorganic filler, Tensile modulus in the first direction (E' １ ) in a second direction perpendicular to the first direction, and the tensile modulus (E' ２ ) divided by (E' １ / E' ２ ) is 1.2 or more.

2. 2. The insulating film for motors according to claim 1, wherein the resin has a glass transition temperature of 50 to 300°C.

3. 2. The insulating film for motors according to claim 1, wherein the resin has a tensile modulus of elasticity of 1.0 GPa or more.

4. The insulating film for a motor according to claim 1 , wherein the resin is a thermoplastic resin.

5. 5. The insulating film for a motor according to claim 4, wherein the thermoplastic resin is at least one selected from the group consisting of polyetherimide, polyaryletherketone, thermoplastic polyimide, aromatic polyamide, aromatic polyester, and polycarbonate.

6. The insulating film for motors according to claim 1 , wherein the inorganic filler is acicular.

7. 2. The insulating film for motors according to claim 1, wherein the inorganic filler is at least one selected from the group consisting of titanium oxide, zinc oxide, alumina, aluminum nitride, boron nitride, boehmite, potassium titanate, and calcium titanate.

8. The tensile modulus in the first direction (E' １ 2. The insulating film for motors according to claim 1, wherein the modulus of elastic modulus is 5 to 10 GPa.

9. The tensile modulus in the second direction (E' ２ 2. The insulating film for motors according to claim 1, wherein the modulus of elastic modulus is 2 to 9 GPa.

10. 2. The insulating film for motors according to claim 1, wherein a compressive strength in the first direction at a thickness of 200 μm is 700 N or more.

11. 2. The insulating film for motors according to claim 1, which has a thickness of 20 to 500 μm.

12. A laminated insulating film for motors, comprising the insulating paper for motors according to any one of claims 1 to 11 and aramid paper on at least one surface thereof.

13. A motor comprising the insulating film for motors according to any one of claims 1 to 11.

14. A method for producing a laminated insulating film for motors, comprising kneading a resin and an inorganic filler having an aspect ratio of 5 to 100, and forming the mixture into a film.

15. The method for producing a laminated insulating film for motors according to claim 14, wherein the resin has a glass transition temperature of 50 to 300°C.

16. The method for producing a laminated insulating film for motors according to claim 14, wherein the resin has a tensile modulus of elasticity of 1.0 GPa or more.

17. The method for producing an insulating film for a motor according to claim 14, wherein the resin is a thermoplastic resin.

18. 18. The method for producing a laminated insulating film for a motor according to claim 17, wherein the thermoplastic resin is at least one selected from the group consisting of polyetherimide, polyaryletherketone, thermoplastic polyimide, aromatic polyamide, aromatic polyester, and polycarbonate.

19. 15. The method for producing a laminated insulating film for motors according to claim 14, wherein the inorganic filler is at least one selected from the group consisting of titanium oxide, zinc oxide, alumina, aluminum nitride, boron nitride, boehmite, potassium titanate, and calcium titanate.

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