Insulation film for motor, and motor

Abstract

To provide an insulation film for a motor which is configured to inhibit occurrence of delamination even if used under high temperature environment.SOLUTION: The invention relates to an insulation film for a motor which includes an aramid paper on at least one surface of a resin layer containing thermoplastic resin, and in which a storage elastic modulus at 150°C is 2.0 GPa or more. The invention also relates to a motor including the insulation film for the motor.SELECTED DRAWING: Figure 1

Description

[Technical Field]

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

[0002] Motors that drive home appliances, industrial equipment, and other devices have traditionally been equipped with insulating films interposed between the core and the winding coil in the slots in the stator core, such as slot paper and wedge paper that blocks the openings of the slot grooves from the inside. These insulating films are usually installed by inserting them into the slots from the openings on the end faces of the stator core. To prevent tearing when inserted into the stator core, the insulating film must have high folding resistance and impact resistance.

[0003] A laminate in which aramid paper and a resin film are bonded together is widely used as such an insulating film. For example, Patent Document 1 discloses an insulating sheet in which aramid paper is used as a substrate and an insulating resin layer made of a thermosetting resin composition is laminated on one or both sides of the substrate via an adhesive or the like.

[0004] In recent years, there has been a demand for motors that are small and highly efficient. To this end, methods have been considered, for example, of thinning the insulating film to increase the space factor of the winding coil. For example, Patent Document 2 discloses an aramid-resin film laminate formed by laminating aramid paper and a resin film, in which one side of the aramid paper is subjected to plasma treatment under predetermined conditions, and the plasma-treated side and the plasma-treated side of the resin film are brought together and bonded together by heating, pressing, or heating and pressing. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2022-185658 [Patent Document 2] Japanese Patent Application Laid-Open No. 2013-223962 Summary of the Invention [Problem to be solved by the invention]

[0006] In recent years, motor performance has improved, creating a demand for insulating films for motors with excellent heat resistance. For example, as motors become more powerful, the temperature environments in which they are used are becoming more severe, and in some cases they are used continuously at temperatures above 150°C. However, conventional insulating films for motors do not have sufficient heat resistance, and delamination (interlayer peeling) can occur when used in high-temperature environments. This delamination (interlayer peeling) is problematic because it makes it impossible to maintain insulation.

[0007] Therefore, in order to solve these problems of the conventional technology, the inventors have conducted research with the aim of providing an insulating film for motors that suppresses the occurrence of delamination (interlayer peeling) even when used in a high-temperature environment. [Means for solving the problem]

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

[0009] [1] An insulating film for motors that has aramid paper on at least one side of a resin layer containing a thermoplastic resin and has a storage modulus of 2.0 GPa or more at 150°C. [2] The insulating film for motors according to [1], wherein the thermoplastic resin has a glass transition temperature of 120 to 250°C. [3] The insulating film for a motor according to [1] or [2], wherein the thermoplastic resin is at least one selected from the group consisting of polyetherimide, thermoplastic polyimide, aromatic polyamide, polycarbonate, and polyaryl ether ketone. [4] The insulating film for a motor according to any one of [1] to [3], wherein the resin layer is provided on both sides with aramid paper. [5] The insulating film for a motor according to any one of [1] to [4], wherein aramid paper is fused to the resin layer. [6] The insulating film for a motor according to any one of [1] to [5], which has a thickness of 20 to 500 μm. [7] The insulating film for a motor according to any one of [1] to [6], wherein the resin layer has a thickness of 10 to 400 μm. [8] The insulating film for a motor according to any one of [1] to [7], which can be bent 100 times or more in the MIT folding endurance test (JIS P8115:2001). [9] The insulating film for a motor according to any one of [1] to [8], which is slotted paper.

[10] A motor equipped with the insulating film for motors according to any one of [1] to [9]. [Effects of the Invention]

[0010] According to the present invention, it is possible to provide an insulating film for a motor in which the occurrence of delamination (interlayer peeling) is suppressed even when used in a high-temperature environment. Therefore, the insulating film for a motor of the present invention can be used as an insulating film for a motor that can maintain its insulating properties for a long period of time in a high-temperature environment. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is a cross-sectional view illustrating the configuration of an insulating film for a motor according to this embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0012] 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."

[0013] (Insulating film for motors) The present embodiment relates to an insulating film for motors (hereinafter, sometimes referred to as "the insulating film") that has aramid paper on at least one side of a resin layer containing a thermoplastic resin and has a storage modulus of 2.0 GPa or more at 150°C. There is no particular upper limit to the storage modulus of the insulating film for motors at 150°C, but it is preferably, for example, 50 GPa or less.

[0014] In this embodiment, the aramid paper may be laminated on only one side of the resin layer, but it is preferable that the aramid paper be laminated on both sides of the resin layer. Fig. 1 discloses an insulating film 10 for a motor in which aramid paper 4 is laminated on both sides of a resin layer 2. The insulating film 10 for a motor preferably has a configuration in which the aramid paper 4, the resin layer 2, and the aramid paper 4 are laminated in this order.

[0015] In addition, in this embodiment, it is preferable that the aramid paper is fused to the resin layer. That is, the resin layer and the aramid paper are not laminated via an adhesive or the like, but are laminated directly. Therefore, this insulating film is an adhesive-free laminated film. Note that, in the process of forming this insulating film, a portion of the aramid constituting the aramid paper may be impregnated into the resin layer. In such a case, this insulating film may have a configuration in which aramid paper, a resin layer at least partially impregnated with aramid, and aramid paper are laminated in this order.

[0016] Because this embodiment has the above-described configuration, delamination (interlayer peeling) is suppressed even when used in a high-temperature environment. Therefore, this insulating film can maintain its insulating properties for a long period of time even in a high-temperature environment. Furthermore, in this embodiment, the resin layer and the aramid paper can be laminated without an adhesive layer between them, making it possible to reduce the thickness. As a result, the coil space factor within the motor can be increased, thereby improving motor efficiency.

[0017] The storage modulus of the insulating film at room temperature (23°C) is preferably 2.0 GPa or more, more preferably 2.2 GPa or more, and even more preferably 2.4 GPa or more. The upper limit of the storage modulus of the insulating film at room temperature (23°C) is not particularly limited, but is preferably 50 GPa or less, for example. By keeping the storage modulus at room temperature (23°C) within the above range, the strength of the insulating film can be increased and the adhesion between the resin layer and the aramid paper can be more effectively improved.

[0018] The storage modulus of this insulating film was measured using a viscoelasticity spectrometer "DVA-200 (manufactured by IT Measurement & Control Co., Ltd.)" in tension mode, with a gauge length of 2 cm, a frequency of 10 Hz, a strain of 0.1%, a temperature range of -50 to 200°C, and a heating rate of 3°C / min, and the storage modulus was measured at room temperature (23°C) and 150°C.

[0019] The present insulating film has excellent folding endurance. Specifically, the number of flexing cycles of the present insulating film in the MIT folding endurance test (JIS P8115:2001) is preferably 100 or more, more preferably 150 or more, even more preferably 200 or more, even more preferably 250 or more, and particularly preferably 300 or more. The upper limit of the number of flexing cycles is not particularly limited and may be, for example, 100,000. The MIT folding endurance test is performed in accordance with JIS P8115:2001, and the flexing test is performed in each of the MD and TD directions of the present insulating film. For the present insulating film, the number of flexing cycles in either the MD or TD is preferably within the above range, but it is more preferable that the number of flexing cycles in both the MD and TD be within the above range. In this specification, the MD direction refers to the flow direction of the resin film, and the TD direction refers to the direction perpendicular to the MD direction.

[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] In the present insulating film, the thickness of the resin layer is preferably smaller than the thickness of the aramid paper. Note that the above thickness refers to the total thickness when multiple layers of each layer are provided. For example, in the present insulating film, when aramid paper, a resin layer, and aramid paper are laminated in this order, the thickness of the resin layer is preferably smaller than the total thickness of the aramid paper. By ensuring the above relationship between the thickness of the resin layer and the thickness of the aramid paper, the folding endurance of the present insulating film can be more effectively improved.

[0022] (resin layer) The insulating film includes a resin layer containing a thermoplastic resin. The thermoplastic resin contained in the resin layer is not particularly limited as long as it is a resin that can give the insulating film a storage modulus of 2.0 GPa or more at 150°C. The glass transition temperature of the thermoplastic resin is preferably 120°C or more, more preferably 130°C or more, and even more preferably 140°C or more. The glass transition temperature of the thermoplastic resin is preferably 250°C or less, more preferably 240°C or less, and even more preferably 230°C or less. Having the glass transition temperature of the resin within the above range facilitates heat fusion with the aramid paper and also makes it easier to achieve a modulus of elasticity of 2.0 GPa or more at 150°C.

[0023] The thermoplastic 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 200°C or higher, more preferably 220°C or higher, and even more preferably 240°C or higher. The crystalline melting temperature (melting point) is preferably 380°C or lower, more preferably 360°C or lower, and even more preferably 340°C or lower. When the crystalline melting temperature (melting point) of the resin is within the above range, it becomes easier to thermally fuse with the aramid paper, and it also becomes easier to achieve an elastic modulus of 2.0 GPa or higher at 150°C.

[0024] As the thermoplastic resin, for example, a thermoplastic resin having a polar group is preferably used. By using a thermoplastic resin having a polar group, interlayer adhesion with the aramid paper can be more effectively improved. More specifically, the thermoplastic resin may be at least one selected from the group consisting of polyetherimide, thermoplastic polyimide, aromatic polyamide, polycarbonate, and polyaryletherketone. Among them, the thermoplastic resin is preferably at least one selected from the group consisting of polyetherimide, aromatic polyamide, polycarbonate, and polyaryletherketone, and polyetherimide is particularly preferred.

[0025] The content of the above resin contained in the resin layer is preferably 50% by mass or more, more preferably 60% by mass or more, even more preferably 70% by mass or more, even more preferably 80% by mass or more, still more preferably 90% by mass or more, particularly preferably 95% by mass or more, and may be 100% by mass, relative to the total mass of the resin layer.

[0026] The thickness of the resin layer is preferably 1 μm or more, more preferably 3 μm or more, and even more preferably 5 μm or more. The thickness of the resin layer 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. The resin layer may have a single-layer structure or a multi-layer structure. In the case of a multi-layer structure, the total thickness of each layer is preferably within the above range.

[0027] <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.

[0028] 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.

[0029] [ka]

[0030] In equation (1), Y 1 ~Y 6 each independently represents a hydrogen atom, an alkyl group, or an alkoxy group; Ar 7 ~Ar 9each 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.

[0031] 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.

[0032] 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 6 The 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 6It is more preferable that all of are hydrogen atoms.

[0033] 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.

[0034] X 1 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-).

[0035] 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 1 and 4 positions, the structure is stable and heat aging resistance is improved, and excellent low water absorption, heat resistance, and impact resistance such as puncture impact strength tend to be easily achieved. Therefore, it is preferable that the polyetherimide has a repeating unit represented by the following structural formula (2).

[0036] [ka]

[0037] 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.

[0038] Y in equation (2) 1 ~Y 6 , X 1 is as explained above. Ar 9 The arylene group in the formula (I) is a 1,4-phenylene group, a 1,4-naphthylene group, a 1, 4-anthracenylene group, etc. 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.

[0039] 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.

[0040] Among these, it is particularly preferable that the polyetherimide used in the resin layer has a repeating unit represented by the following structural formula (3). When the polyetherimide has the following structure, the 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.

[0041] [ka]

[0042] 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.

[0043] 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]

[0044] 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.

[0045] 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.

[0046] As PEI, for example, products commercially available from Sabic Innovative Plastics under the trade name "Ultem" series can be used.

[0047] <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).

[0048] 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.

[0049] 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.

[0050] 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.

[0051] 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.

[0052] 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 branched aliphatic diamines include those in which a branched structure having preferably 1 to 20 carbon atoms, more preferably 1 to 10 carbon atoms, is bonded 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.

[0053] 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.

[0054] 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.

[0055] The thermoplastic polyimide may be crystalline. A crystalline thermoplastic polyimide exhibits 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 laminated 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.

[0056] 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.

[0057] <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.

[0058] 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 the total 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 that is excellent in both low water absorption and heat resistance.

[0059] 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 that is excellent in both low water absorption and heat resistance.

[0060] 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 that is excellent in both low water absorption and heat resistance.

[0061] 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 that is excellent in both low water absorption and heat resistance.

[0062] 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).

[0063] 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.

[0064] 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.

[0065] <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.

[0066] [ka]

[0067] Of the above, polycarbonates having a structural unit represented by the following formula (6) are preferred.

[0068] [ka]

[0069] 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.

[0070] 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.

[0071] 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.

[0072] Specific examples of suitable structural units of polycarbonate are shown below, but polycarbonate is not limited to these.

[0073] [ka]

[0074] 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.

[0075] <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).

[0076] [ka]

[0077] [ka]

[0078] [ka]

[0079] [ka]

[0080] [ka]

[0081] 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).

[0082] 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.

[0083] 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.

[0084] <Optional ingredients> The resin layer 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.

[0085] (aramid paper) The insulating film includes aramid paper, which is preferably a sheet-like material made by papermaking aramid short fibers.

[0086] 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.

[0087] The thickness of the aramid paper 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.

[0088] The basis weight of aramid paper 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.

[0089] Aramid staple fibers are fibers made from aramid and cut to a predetermined length. Examples of aramid staple fibers include "Conex (registered trademark)" and "Technora (registered trademark)" from Teijin Techno Products Co., Ltd., "Nomex (registered trademark)" and "Kevlar (registered trademark)" from DuPont, and "Tokuron (registered trademark)" from Tokushu Tokai Paper Co., Ltd.

[0090] The fineness of the aramid short fibers is preferably 0.05 dtex or more and less than 25 dtex. By setting the fineness of the aramid short fibers within the above range, aggregation can be suppressed when producing aramid paper by a wet papermaking method, and uniform aramid paper can be more easily obtained.

[0091] 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.

[0092] 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.

[0093] (Method of manufacturing insulating film for motors) An insulating film for a motor having a resin layer and aramid paper is produced, for example, by thermally laminating the resin film and the aramid paper.

[0094] <Method of manufacturing resin film> The resin film can be produced by a general molding method, such as extrusion molding, injection molding, blow molding, vacuum molding, pressure molding, press molding, etc. Although the apparatus and processing conditions for each molding method are not particularly limited, it is preferable to employ extrusion molding, particularly the T-die method, from the viewpoints of productivity and thickness control.

[0095] The method for producing the resin film is not particularly limited, but for example, the constituent material of the film can be obtained as an unstretched or stretched film, and from the viewpoint of secondary processability, it is preferable to obtain it as an unstretched film. Note that an unstretched film is a film that is not actively stretched for the purpose of controlling the orientation of the sheet, and also includes a film that is oriented when taken up by a cast roll in the T-die method.

[0096] In the case of a non-stretched film, for example, the constituent materials can be melt-kneaded, followed by extrusion molding and cooling. A known kneader such as a single-screw or twin-screw extruder can be used for the melt-kneading. Molding can be carried out, for example, by extrusion molding using a mold such as a T-die.

[0097] The resin film may be a laminated film. When producing a laminated film, the lamination method is not particularly limited, and for example, any of 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 shape and then laminated, and a thermocompression bonding method in which each layer is formed into a film shape and then thermocompression bonded may be used. From the viewpoint of productivity, however, the coextrusion method is preferable. Coextrusion methods include a multi-manifold method in which the constituent materials of each layer are joined at a die, a feed block method in which the materials are joined at a feed block, and the like, and any of these may be used.

[0098] The resin film may be subjected to a surface treatment, such as a plasma treatment or a corona treatment.

[0099] <Aramid paper manufacturing method> Aramid paper is produced, for example, by mixing the above-mentioned aramid short fibers and aramid fibrids and then forming them into a sheet. For example, there is a method (airlaid method) in which the aramid short fibers and aramid fibrids are dry-blended, and then deposited in a sheet form using an airflow to form a sheet, or a method in which the aramid short fibers and aramid fibrids are dispersed and mixed in a liquid medium to form a slurry, and then the slurry is wet-laid. In the wet papermaking method, an aqueous slurry containing at least aramid fibrids and aramid short 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.

[0100] 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.

[0101] 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.

[0102] <Lamination method> Methods for laminating aramid paper and a 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 before laminating the aramid paper and the 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.

[0103] After the preheating step of the resin film, it is preferable to provide a step of laminating the preheated resin film and aramid paper and heat-pressing them. Examples of the heat-pressing step include a method of laminating the laminate of the resin film and aramid paper by heat pressing, or a step of passing the laminate between a pair of heated rolls. The heat-pressing conditions are preferably 260°C or higher, which is the softening temperature of the resin, more preferably 280°C or higher, even more preferably 300°C or higher, and particularly preferably 320°C or higher. The upper limit of the heating temperature is not particularly limited, but is preferably, for example, 500°C or lower, depending on the upper limit of the equipment. The pressure during heat-pressing is preferably 0.1 MPa or higher, more preferably 0.2 MPa or higher, and even more preferably 0.3 MPa or higher. The upper limit of the pressure is not particularly limited, but is preferably, for example, 20 MPa or lower, depending on the upper limit of the equipment.

[0104] (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 in motors and 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, with slot paper being particularly preferred. Slot paper is inserted so that it fits along the inner circumferential surface of the slot (groove) in the motor stator. This insulating film is resistant to deformation and cracking when inserted into the slot, allowing it to be used without problems of poor insulation.

[0105] This embodiment may also relate to a motor equipped with the insulating film for a motor described above. This insulating film can be made thin and is less susceptible to delamination (interlayer peeling) even when used in a high-temperature environment, making it suitable for use in small, high-output motors. [Example]

[0106] 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.

[0107] (1) Storage modulus (room temperature / 150°C) Test pieces measuring 4 mm in width and 8 cm in length were prepared from the insulating films for motors obtained in the examples and comparative examples, and the storage modulus was measured at room temperature (23°C) and 150°C using a viscoelasticity spectrometer "DVA-200 (manufactured by IT Measurement & Control Co., Ltd.)" with the measurement mode set to tension, a gauge length of 2 cm, a frequency of 10 Hz, a strain of 0.1%, a temperature range of -50 to 200°C, and a heating rate of 3°C / min. If the film to be used as the test piece had directionality, the measurement was performed in the direction (TD) perpendicular to the resin flow direction of the film (extrusion direction in the case of extrusion molding). If the resin of the film had no directionality, the measurement was performed in only one direction.

[0108] (2) Glass transition temperature In accordance with JIS K7121:2012, a differential scanning calorimeter Pyris1 DSC (manufactured by PerkinElmer) was used to determine the glass transition temperature (Tg) of the raw material pellets from the inflection point of the DSC detected during the reheating process in the temperature range of 25 to 280°C at a heating rate of 10°C / min, and the crystalline melting temperature (Tm) from the endothermic peak of the DSC.

[0109] (3) Folding endurance test Based on JIS K7127, the MIT folding endurance test was conducted under the conditions of 9.8N, 175 times / min, and 135°. Those that were bent 100 times or more were rated A, and those that were bent less than 100 times were rated C.

[0110] (4) Heat resistance test Immediately after leaving the aramid paper in a 150°C oven for 30 minutes, the aramid paper and resin were peeled off. The samples that did not peel off or tear, just like at room temperature, were classified as A, those that showed tears in the adhesive layer were classified as B, and those that peeled off immediately after removing from the oven were classified as C.

[0111] The following materials were used as constituent materials of the insulating film for motors.

[0112] [Polyetherimide] (1)PEI1000: Ultem 1000-1000 (manufactured by Sabic, Tg=213℃) (2) PEI5000: Ultem CRS5001-1000 (manufactured by Sabic, Tg=225℃)

[0113] [Thermoplastic polyimide] TPI: Surprim TO-65 (Mitsubishi Gas Chemical Company, Inc., Tg = 180°C, Tm = 322°C) Tetracarboxylic acid component: pyromellitic acid = 100 mol%, Diamine component: 1,3-bis(aminomethyl)cyclohexane / octamethylenediamine = 60 / 40 mol%

[0114] [Aromatic polyamide] Aromatic PA: Genestar TS-296 (PA9T) (Kuraray, Tg = 128°C, Tm = 267°C), terephthalic acid / 1,9-nonanediamine / 2-methyl-1,8-octanediamine = 50 / 25 / 25 mol%

[0115] [Polycarbonate] PC: Novarex 7022R (A-type polycarbonate) (Mitsubishi Engineering Plastics, Tg = 147°C)

[0116] [Polyethylene naphthalate] PEN: Teonex (Teijin, thickness 100 μm)

[0117] [Polyphenylene sulfide] PPS: Torelina (manufactured by Toray Industries, thickness 100 μm) [Aramid paper] Nomex 410 (DuPont, thickness 50 μm)

[0118] [glue] An acrylic adhesive was used.

[0119] Example 1 The polyetherimide raw material was melt-kneaded using a Φ40 mm single-screw extruder and continuously extruded through a T-die to obtain a resin film with a thickness of 50 μm. The extruder temperature and die temperature were both 380°C.

[0120] Aramid paper, resin film and aramid paper were laminated in this order and then heated and pressurized using a metal calendar roll at a temperature of 380°C and a pressure of 0.3 MPa to obtain an insulating film for motors consisting of aramid paper / PEI / aramid paper.

[0121] Examples 2 to 5 Resin films were obtained in the same manner as in Example 1, except that the raw materials for producing the resin films were changed as shown in Table 1. However, the extrusion temperature in Example 3 was 350°C, the extrusion temperature in Example 4 was 320°C, and the extrusion temperature in Example 5 was 280°C.

[0122] (Comparative Example 1) After obtaining a resin film in the same manner as in Example 2, adhesive was applied to both sides of the resin film using a bar coating method to a thickness of 25 μm, and the film was then bonded to aramid paper to obtain an insulating film for motors with a thickness of 200 μm.

[0123] (Comparative Example 2) An insulating film for a motor was produced in the same manner as in Comparative Example 1, except that the resin film used was changed as shown in Table 1 and the thickness of the adhesive layer was changed to 30 μm.

[0124] (Comparative Example 3) A resin film was obtained in the same manner as in Example 2, and this resin film was evaluated as an insulating film for a motor.

[0125] Comparative Example 4 An insulating film for a motor was produced in the same manner as in Example 1, except that the resin film used was changed as shown in Table 1.

[0126] [Table 1]

[0127] The motor insulating films obtained in the examples were excellent in folding resistance and did not suffer from delamination (interlayer peeling) even at high temperatures. Therefore, the motor insulating films of the examples can be used as motor insulating films that can maintain their insulation properties for long periods of time in high-temperature environments. Furthermore, because the motor insulating films obtained in the examples have an adhesive-free structure, they can be made thinner, allowing for a larger coil space factor within the motor. On the other hand, in Comparative Examples 1 and 2, the adhesive layer was provided, which increased the overall thickness and reduced the storage modulus at 150°C, causing delamination during use at high temperatures, resulting in a loss of adhesiveness and impaired insulation. Furthermore, Comparative Example 3 was not laminated with aramid paper, resulting in poor folding endurance, and Comparative Example 4 had a small storage modulus at 150°C, causing delamination (interlayer peeling) even at high temperatures, thereby impairing insulation. [Explanation of symbols]

[0128] 2 Resin layer 4. Aramid paper 10. Motor insulating film

Claims

1. An insulating film for motors, comprising aramid paper on at least one side of a resin layer containing a thermoplastic resin, and having a storage modulus at 150°C of 2.0 GPa or more.

2. 2. The insulating film for motors according to claim 1, wherein the thermoplastic resin has a glass transition temperature of 120 to 250° C.

3. 2. The insulating film for a motor according to claim 1, wherein the thermoplastic resin is at least one selected from the group consisting of polyetherimide, thermoplastic polyimide, aromatic polyamide, polycarbonate, and polyaryl ether ketone.

4. The insulating film for a motor according to claim 1 , further comprising aramid paper on both sides of the resin layer.

5. The insulating film for a motor according to claim 1 , wherein an aramid paper is fused to the resin layer.

6. 2. The insulating film for motors according to claim 1, having a thickness of 20 to 500 μm.

7. 2. The insulating film for a motor according to claim 1, wherein the resin layer has a thickness of 10 to 400 μm.

8. 2. The insulating film for motors according to claim 1, which has a bending endurance of 100 or more times in an MIT folding endurance test (JIS P8115:2001).

9. The insulating film for motors according to claim 1 , which is a slotted paper.

10. A motor comprising the insulating film for motors according to any one of claims 1 to 9.

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