Rotary electric machine insulation material and rotary electric machine

Abstract

To provide a rotary electric machine insulation material and a rotary electric machine which can be used in a bending process, and further, the insulation properties of which can be stabilized.SOLUTION: In a rotary electric machine insulation material, a resin film is used to insulate a motor 2 of a rotary electric machine 1. As the resin film, a thermoplastic polyimide resin film 10 is used. The maximum strength of the thermoplastic polyimide resin film 10 at 23°C is 50 MPa or greater if measured in accordance with JIS K7127, the breaking elongation of the thermoplastic polyimide resin film 10 at 23°C is 50% or greater if measured in accordance with JIS K7127, the elastic modulus of the thermoplastic polyimide resin film 10 at 23°C is 2000 to 5000 MPa if measured in accordance with JIS K7127, and the water absorptivity of the thermoplastic polyimide resin film 10 at 23°C is 1.0% or less if measured in accordance with JIS K7209 A.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an insulating material for a rotating electric machine, which is capable of maintaining the insulation properties of a motor or generator and preventing short circuits and the like, and to a rotating electric machine. [Background technology]

[0002] In recent years, due to the growing awareness of environmental issues, the development of transportation systems that run on motors (engineers) such as electric vehicles (EVs), hybrid vehicles (HVs or HEVs), plug-in hybrid vehicles (PHVs), fuel cell vehicles (FCVs), electric vehicles, or electric locomotives has been in the spotlight. The motors used in these transportation systems have been made smaller, more powerful, and more efficient, but along with the miniaturization, higher power, and higher efficiency, there has been a rapid increase in the trend toward higher voltage and current. Therefore, the insulating materials used in future motors will be required to have better electrical insulation properties, mechanical properties, and heat resistance than ever before. In order to meet these requirements, polyimide resins have been considered as insulating materials in recent years.

[0003] Polyimide resins have excellent properties such as electrical insulation, mechanical properties, heat resistance, chemical resistance, and hydrolysis resistance, and in view of these excellent properties, their use has been considered and they are being used in a wide range of fields such as the automotive field, the energy field, the electrical / electronic field, the aerospace field, etc. There are thermoplastic (also called heat-fusible) polyimide resins and thermosetting (also called heat-insoluble) polyimide resins, and thermosetting polyimide resin films have excellent electrical insulation, mechanical properties, chemical resistance, and hydrolysis resistance, and therefore are being considered for use as insulating materials for motors (see Patent Documents 1 and 2).

[0004] Specifically, Kapton (registered trademark), a type of thermosetting polyimide resin film, has been studied and proposed as an insulating sheet or interlayer insulator. In this case, the insulating sheet is used, for example, as (1) a slot material that is manually inserted between the inner wall surface of a stator slot and the conductive winding housed in the slot in order to ensure insulation between the stator core and the conductive winding (see Patent Document 3), (2) a wedge that is attached to block the entrance of the stator core and prevents the conductive winding from falling off (see Patent Document 4), or (3) an interphase insulating sheet that is interposed between conductive windings of different phases in a three-phase AC motor or the like (see Patent Document 5). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 6599550 [Patent Document 2] Patent No. 6893274 [Patent Document 3] JP 2018-74672 A [Patent Document 4] Japanese Patent Application Publication No. 7-222387 [Patent Document 5] JP 2012-170248 A Summary of the Invention [Problem to be solved by the invention]

[0006] Conventional motor insulating sheets use Kapton, which is a thermosetting polyimide resin, as described above, and therefore can provide excellent electrical insulation properties, mechanical properties, chemical resistance, and hydrolysis resistance. However, since Kapton is a thermosetting polyimide resin, it can be used for interlocking insulating sheets that do not require folding, but it is not easy to use it for slot materials or wedges that require folding. To explain this point, folding requires thermal processing, but Kapton is heat insoluble and has a high elastic modulus. Therefore, when Kapton is used, problems arise in that the folded portion returns to its original state due to springback after processing, or cracks occur during processing.

[0007] In addition, since thermosetting polyimide resins have a high water absorption rate, even if they have some excellent electrical insulating properties, they do not have all excellent electrical insulating properties. For example, there are problems with stabilizing the insulating properties.

[0008] The present invention has been made in view of the above, and has an object to provide an insulating material for a rotating electric machine, and a rotating electric machine, which can be used in bending processing and have stable insulating properties. [Means for solving the problem]

[0009] As a result of extensive research, the present inventors focused on thermoplastic polyimide resins, rather than thermosetting polyimide resins, and completed the present invention.

[0010] That is, in order to solve the above problems, the present invention uses a resin film for insulation of a rotating electric machine, The resin film is a thermoplastic polyimide resin film, which has a maximum strength of 50 MPa or more at 23°C when measured in accordance with JIS K7127, a breaking elongation of 50% or more at 23°C when measured in accordance with JIS K7127, a modulus of elasticity of 2000 MPa or more and 5000 MPa or less at 23°C when measured in accordance with JIS K7127, and a water absorption of 1.0% or less at 23°C when measured in accordance with JIS K7209 Method A.

[0011] The thermoplastic polyimide resin film preferably has a thickness of 25 μm or more and 500 μm or less, and the sliding property between the thermoplastic polyimide resin film and a stainless steel plate at 23° C. is preferably such that the static friction coefficient is 0.1 to 0.5 and the dynamic friction coefficient is 0.1 to 0.5. In addition, the thermoplastic polyimide resin film preferably has a dielectric breakdown voltage in silicone oil at 23° C. of 4 kV or more and 80 kV or less when measured in accordance with IEC 60243-1. Furthermore, the dielectric breakdown voltage of the thermoplastic polyimide resin film in silicone oil at 200° C. is preferably 4 kV or more and 70 kV or less when measured in accordance with IEC 60243-1.

[0012] It is also preferable that the thermoplastic polyimide resin film has a relative dielectric constant of 3.5 or less at 23° C. when measured at a frequency of 1 GHz, and a dielectric loss tangent of 0.003 to 0.008 at 23° C. when measured at a frequency of 1 GHz. In addition, when the storage modulus of the thermoplastic polyimide resin film at 200°C was measured, it was 1.0×10 7 Pa or more 2.1×10 9 Pa or less is better.

[0013] In order to solve the above-mentioned problems, the present invention is characterized in that a stator surrounding a rotor is composed of a core that is fitted into the rotor, a slot that is recessed into the surface of the core that faces the rotor, and a conductive winding that is housed in the slot, and an insulating wall member is interposed between the slot and the conductive winding, and this wall member is an insulating material for a rotating electric machine as described in claim 1 or 2.

[0014] In addition, in order to solve the above-mentioned problems, the present invention is characterized in that a stator surrounding a rotor is composed of a core fitted to the rotor, a slot formed as a recess in the surface of the core facing the rotor, and a conductive winding housed in the slot, and an insulating wall member is interposed between the slot and the conductive winding and bent into a generally U-shaped cross section to sandwich the conductive winding, and an insulating installation member is installed between a plurality of opposing pieces of the wall member that face each other with the conductive winding in between, and the wall member and the installation member are each made of an insulating material for a rotating electric machine as described in claim 1 or 2.

[0015] Here, the thermoplastic polyimide resin film in the claims may be either an amorphous thermoplastic polyimide resin film having a glass transition point of 200° C. or higher, or a crystalline thermoplastic polyimide resin film having a melting point of 300° C. or higher. This thermoplastic polyimide resin film can be produced by a melt extrusion molding method in which a molding material containing a thermoplastic polyimide resin is melt-kneaded using a melt extruder, the molten thermoplastic polyimide resin is continuously extruded in a strip shape from the die of the melt extruder, and the thermoplastic polyimide resin is sandwiched between a pressure roll and a cooling roll and cooled.

[0016] The thermoplastic polyimide resin film may be used alone, or may be used in a state where it is laminated on a resin fiber sheet, etc. Furthermore, the rotating electric machine according to the present invention includes at least various types of motors and generators.

[0017] According to the present invention, the maximum strength of the thermoplastic polyimide resin film at 23°C is 50 MPa or more, and the elongation at break of the thermoplastic polyimide resin film at 23°C is 50% or more, so that the thermoplastic polyimide resin film can be given sufficient toughness. In addition, the elastic modulus of the thermoplastic polyimide resin film at 23°C is 2000 MPa or more and 5000 MPa or less, so that the rigidity can be improved. In addition, the water absorption rate of the thermoplastic polyimide resin film is reduced to 1.0% or less, so that high electrical insulation can be maintained even in a high temperature and humidity environment. Effect of the Invention

[0018] According to the present invention, a thermoplastic polyimide resin film is used for insulation of a rotating electrical machine, and the thermoplastic polyimide resin film has a maximum strength of 50 MPa or more when measured in accordance with JIS K7127, a breaking elongation of 50% or more when measured in accordance with JIS K7127, a modulus of elasticity of 2000 MPa or more and 5000 MPa or less when measured in accordance with JIS K7127, and a water absorption of 1.0% or less when measured in accordance with JIS K7209 Method A. Therefore, the thermoplastic polyimide resin film can be used in bending processing and has stable insulating properties.

[0019] According to the invention described in claim 2, the dielectric breakdown voltage of the thermoplastic polyimide resin film in silicone oil at 23°C is 4 kV to 80 kV when measured in accordance with IEC 60243-1, so that even if the thermoplastic polyimide resin film is used as an insulating material for a rotating electrical machine, the risk of dielectric breakdown due to surge voltage can be eliminated. Also, it is possible to prevent the thermoplastic polyimide resin film from becoming too thick and hindering the miniaturization of the rotating electrical machine.

[0020] According to the invention described in claim 3, the dielectric breakdown voltage of the thermoplastic polyimide resin film in silicone oil at 200°C is 4 kV to 70 kV when measured in accordance with IEC 60243-1, so that even if the thermoplastic polyimide resin film is used as an insulating material for a rotating electrical machine, the risk of dielectric breakdown due to surge voltage can be eliminated. Also, it is possible to prevent the thermoplastic polyimide resin film from becoming too thick and hindering the miniaturization of the rotating electrical machine.

[0021] According to the invention described in claim 4, the relative dielectric constant of the thermoplastic polyimide resin film at 23°C is 3.5 or less when measured at a frequency of 1 GHz, and the dielectric tangent at 23°C is 0.003 to 0.008 when measured at a frequency of 1 GHz, so that it is possible to prevent the thermoplastic polyimide resin film from melting or decomposing due to self-heating.

[0022] According to the invention described in claim 5, when the storage modulus of the thermoplastic polyimide resin film at 200°C is measured, it is 1.0 × 10 7 Pa or more 2.1×10 9 Since the compressive strength is set to be equal to or less than 1 Pa, sufficient heat resistance can be obtained even in high temperature ranges. For example, even if the thermoplastic polyimide resin film is used in a high temperature range of 200°C, it is possible to prevent the thermoplastic polyimide resin film from softening and deforming.

[0023] According to the invention described in claim 6, since the thermoplastic polyimide resin film has excellent heat resistance and chemical resistance, it can be suitably used for insulating motors of electric vehicles, hybrid vehicles, plug-in hybrid vehicles, fuel cell vehicles, etc. In addition, even if the thermoplastic polyimide resin film is processed and used as a wall member of a slot of a rotating electric machine, the folded part after processing is unlikely to return to its original state, and cracks are unlikely to occur during processing. In addition, since the elastic modulus of the thermoplastic polyimide resin film at 23°C is 2000 MPa or more and 5000 MPa or less, the rigidity can be improved, and even if the thermoplastic polyimide resin film is folded into the wall member of the slot and inserted into the slot, the risk of buckling can be eliminated.

[0024] According to the invention described in claim 7, for example, when the rotating electric machine is a polyphase AC motor, the installation member can ensure insulation between each phase of the polyphase coil and prevent the conductive windings from protruding from within the wall member while maintaining electrical insulation. [Brief description of the drawings]

[0025] [Figure 1] 1 is a plan sectional view that illustrates an example of an insulating material for a rotating electric machine and a rotating electric machine according to the present invention; [Diagram 2] 1 is a perspective explanatory view showing a schematic relationship between a stator core and slots, and a thermoplastic polyimide resin film in an embodiment of an insulating material for a rotating electric machine and a rotating electric machine according to the present invention; FIG. [Diagram 3] 1 is a perspective explanatory view showing a schematic view of a core and slots of a stator in an embodiment of a rotating electric machine according to the present invention; [Figure 4] 1 is an explanatory diagram illustrating a thermoplastic polyimide resin film in an embodiment of an insulating material for a rotating electric machine according to the present invention; [Diagram 5] 1 is an overall explanatory diagram showing a schematic diagram of a manufacturing apparatus for a thermoplastic polyimide resin film in an embodiment of an insulating material for a rotating electric machine according to the present invention; [Figure 6]FIG. 4 is a cross-sectional explanatory view showing a schematic diagram of a second embodiment of an insulating material for a rotating electric machine and a rotating electric machine according to the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0026] A preferred embodiment of the present invention will be described below with reference to the drawings. In the insulating material for a rotating electric machine in this embodiment, as shown in Figures 1 to 5, a resin film used for insulating a rotating electric machine 1 is a thermoplastic polyimide resin film 10, and the thermoplastic polyimide resin film 10 has a maximum strength of 50 MPa or more at 23°C, an elongation at break of 50% or more at 23°C, an elastic modulus of 2000 MPa or more and 5000 MPa or less at 23°C, and a water absorption rate of 1.0% or less at 23°C, thereby contributing to the achievement of Goal 9 of the SDGs (the United Nations' international goals for sustainable development, consisting of 17 global goals and 169 targets (achievement criteria)) adopted at the United Nations Summit.

[0027] As partially shown in Figures 1 to 3, the rotating electric machine 1 is composed of a motor 2 for, for example, an electric vehicle or a hybrid vehicle, and a stator 3 that surrounds the rotor from the outside and rotates it is installed on the inner periphery of a housing. The stator 3 includes a cylindrical core 4 that is fitted to a rotatable rotor, and a plurality of conductive windings 6 that are housed in the core 4, and a plurality of slots 5 are formed in a line in the circumferential direction of the inner periphery of the core 4 that faces the rotor, and a plurality of conductive windings 6 that generate a magnetic field are wound in the plurality of slots 5 and indirectly housed therein. As shown in Figures 1 to 3, the core 4 is formed by laminating iron cores made of a plurality of silicon steel plates or the like, or is integrally molded, from the viewpoint of reducing the influence of eddy currents.

[0028] Each slot 5 is recessed to form an approximately U-shape, with its opening directed toward the center of the core 4 and its bottom formed as a flat or curved surface. The opening of the slot 5 is formed narrower than the bottom as necessary to prevent the insulating thermoplastic polyimide resin film 10 from popping out or falling off. Each conductive winding 6 is mainly made of distributed wound round copper wire, but when it is desired to improve the winding density, flat copper wire with a rectangular (square) cross section is used.

[0029] 1, 2 and 4, the thermoplastic polyimide resin film 10 is formed by a molding method such as melt extrusion molding using a melt extruder 20, and is bent into a generally flexible U-shape in planar form, and is detachably positioned and fitted into the slot 5 with its opening facing the center of the core 4, and is interposed between the slot 5 and the conductive windings 6 as an insulating wall member 11, and directly houses the conductive windings 6 in a sandwiched state. The upper and lower end portions 12 of this thermoplastic polyimide resin film 10 in Fig. 2 are folded outward, and these upper and lower end portions 12 engage with the peripheral portions of the slot on the front and back surfaces of the core 4, respectively, to prevent misalignment or falling off.

[0030] In this way, the thermoplastic polyimide resin film 10 directly houses the multiple conductive windings 6, and as a result of this housing, it is present as an insulating wall between the inner surface of the slot 5 and the multiple conductive windings 6, isolating the slot 5 from the multiple conductive windings 6 and ensuring insulation between them. The thermoplastic polyimide resin film 10 is used as an insulating wall because it can improve electrical insulation properties including insulation, mechanical properties, heat resistance, chemical resistance, radiation resistance, hydrolysis resistance, low water absorbency, thermal processability, recyclability, and the like.

[0031] The thermoplastic polyimide resin of the thermoplastic polyimide resin film 10 may be amorphous or crystalline, so long as it is a polyimide resin having thermoplasticity (also called heat melting property). As the amorphous thermoplastic polyimide resin, a thermoplastic polyimide resin having a glass transition point (hereinafter referred to as Tg) of 200°C or more is preferable from the viewpoint of obtaining excellent heat resistance. An example of this amorphous thermoplastic polyimide resin is polyetherimide resin. On the other hand, as the crystalline thermoplastic polyimide resin, a thermoplastic polyimide resin having a melting point (hereinafter referred to as Tm) of 300°C or more is preferable from the viewpoint of obtaining excellent heat resistance. As the crystalline thermoplastic polyimide resin, a thermoplastic polyimide resin consisting of a diamine component and a terephthalic acid component is preferable.

[0032] When the thermoplastic polyimide resin used in the present embodiment is an amorphous thermoplastic polyimide resin, a polyetherimide resin having a Tg of 200° C. or more is optimal. This polyetherimide resin is not particularly limited as long as it is amorphous and has repeated ether bonds and imide bonds in the main chain. Specific examples include a polyetherimide resin having a repeating unit represented by the following structural formula (1) and a polyetherimide resin having a repeating unit represented by the following structural formula (2).

[0033] [ka]

[0034] [ka]

[0035] Specific examples of the polyetherimide resin of the above structural formula (1) include ULTEM 1000-1000-NB (product name, manufactured by Savic Innovative Plastics), ULTEM 1010-1000-NB (product name, manufactured by Savic Innovative Plastics), and ULTEM 9011-1000-NB (product name, manufactured by Savic Innovative Plastics), which are produced from a polycondensate of 4,4'-[isopropylidene(p-phenyleneoxy)]diphthalic acid and m-phenylenediamine.

[0036] A specific example of the polyetherimide resin of the above structural formula (2) is ULTEM CRS5001-1000-NB (product name, manufactured by Sabic Innovative Plastics Co., Ltd.), which is produced from a polycondensate of 4,4'-[isopropylidene(p-phenyleneoxy)]diphthalic acid and p-phenylenediamine. Methods for producing this polyetherimide resin include those described in, for example, Japanese Patent Publication No. 57-9372 and Japanese Patent Publication No. 58-46244.

[0037] The polyetherimide resin, which is an amorphous thermoplastic polyimide resin, may be a block copolymer, a random copolymer, or a modified product with a copolymerizable monomer such as an amide group, an ester group, or a sulfone group, as long as the effect of the present invention is not impaired. For example, ULTEM XH6050-1000 (product name, manufactured by SABIC Innovative Plastics), which is a polyetherimide sulfone resin, may be used. One type of this polyetherimide resin may be used alone, or two or more types may be alloyed or blended to be used.

[0038] The Tg of the polyetherimide resin is usually in the range of 200° C. to 300° C., preferably 210° C. to 280° C., more preferably 210° C. to 260° C., and even more preferably 210° C. to 250° C. This is because if the Tg of the polyetherimide resin is less than 200° C., the heat resistance of the wall member 11 obtained from the polyetherimide resin will be insufficient. The Tg (unit:° C.) of the polyetherimide resin can be determined by thermal analysis using a differential scanning calorimeter.

[0039] The apparent melt viscosity of polyetherimide resin is 5.0×10 when measured with a constant load extrusion capillary rheometer using a die with a diameter of 1.0 mm and a length of 10 mm under conditions of a temperature of 370°C and a load of 50 kgf. 1 Pa·s or more 5.0×10 4 Within the range of Pa s or less, preferably 1.0×10 2 Pa·s or more 1.0×10 4 Within the range of Pa s or less, preferably 2.5×10 2 Pa·s or more 7.5×10 3 Pa s or less, more preferably 2.5×10 2 Pa·s or more 5.0×10 3 It is better if it is in the range of Pa·s or less.

[0040] This is because the apparent melt viscosity is 5.0 × 10 1 If it is less than 5.0×10 Pa·s, the melt tension of the polyetherimide resin is small, and problems occur in the formability of the resin film by melt extrusion molding when it is melt extrusion molded. 4 If it exceeds Pa·s, an excessive load is applied to the melt extruder 20, making it difficult to form a good resin film by melt extrusion.

[0041] When the thermoplastic polyimide resin used in the present embodiment is crystalline, examples of the crystalline thermoplastic polyimide resin include a thermoplastic polyimide resin composed of a diamine component and a tetracarboxylic acid component. Examples of the crystalline thermoplastic polyimide resin include a thermoplastic polyimide resin obtained by dehydrating and cyclizing a polyamic acid obtained by reacting a diamine component with a tetracarboxylic dianhydride, and a thermoplastic polyimide resin composed of a diamine component mainly composed of an aliphatic diamine component and a tetracarboxylic acid component.

[0042] The diamine component used in the thermoplastic polyimide resin obtained by dehydrating and cyclizing the polyamic acid obtained by reacting the diamine component with a tetracarboxylic dianhydride can be a monocyclic aromatic group having one benzene ring, a condensed polycyclic aromatic group having a naphthalene group, or a non-condensed polycyclic aromatic group in which multiple aromatic groups are linked to each other by a direct bond, a carbonyl group, a sulfone group, a sulfide group, a sulfoxide group, an ether group, or a crosslinker of a sulfide group. Examples of the diamine component include the diamines described in JP-A-2004-27137 and JP-A-4629894.

[0043] Specific examples of the diamine include the following diamines: 4,4'bis(3-aminophenoxy)biphenyl, m-phenylenediamine, o-phenylenediamine, p-phenylenediamine, m-aminobenzylamine, p-aminobenzylamine, 3,3'-diaminodiphenyl ether, 4,4'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, bis(3-aminophenyl)sulfide, bis(4-aminophenyl)sulfide, (3-aminophenyl)(4-aminophenyl)sulfide, bis(3-aminophenyl) Sulfoxide, bis(4-aminophenyl)sulfoxide, (3-aminophenyl)(4-aminophenyl)sulfoxide, bis(3-aminophenyl)sulfone, bis(4-aminophenyl)sulfone, (3-aminophenyl)(4-aminophenyl)sulfone, 3,3'-diaminobenzophenone, 4,4'-diaminobenzophenone, 3,4'-diaminobenzophenone, 3,3'-diaminodiphenylmethane, 4,4'-diaminodiphenylmethane, 3,4'-diaminodiphenylmethane, bis[ 4-(3-aminophenoxy)phenyl]methane, bis[4-(4-aminophenoxy)phenyl]methane, 1,1-bis[4-(3-aminophenoxy)phenyl]ethane, 1,2-bis[4-(3-aminophenoxy)phenyl]ethane, 1,1-bis[4-(4-aminophenoxy)phenyl]ethane, 1,2-bis[4-(4-aminophenoxy)phenyl]ethane, 2,2-bis[4-(3-aminophenoxy)phenyl]propane, 2,2-bis[4-(4-aminophenoxy)phenyl]propane propane, 2,2-bis[4-(3-aminophenoxy)phenyl]butane, 2,2-bis[3-(3-aminophenoxy)phenyl]1,1,1,3,3,3-hexafluoropropane, 2,2-bis[4-(4-aminophenoxy)phenyl]1,1,1,3,3,3-hexafluoropropane, 1,3-bis(3-aminophenoxy)benzene, 1,3-bis(4-aminophenoxy)benzene, 1,4-bis(3-aminophenoxy)benzene, 1,4-bis(4-aminophenoxy)benzene, 4,4'-Bis(4-aminophenoxy)biphenyl, bis[4-(3-aminophenoxy)phenyl]ketone, bis[4-(4-aminophenoxy)phenyl]ketone, bis[4-(3-aminophenoxy)phenyl]sulfide, bis[4-(4-aminophenoxy)phenyl]sulfide, bis[4-(3-aminophenoxy)phenyl]sulfoxide, bis[4-(4-aminophenoxy)phenyl]sulfoxide, bis[4-(3-aminophenoxy)phenyl]sulfone, bis[4-(4-aminophenoxy)phenyl]sulfone, bis[4- (3-aminophenoxy)phenyl]ether, bis[4-(4-aminophenoxy)phenyl]ether, 1,4-bis[4-(3-aminophenoxy)benzoyl]benzene, 1,3-bis[4-(3-aminophenoxy)benzoyl]benzene, 4,4'-bis[3-(4-aminophenoxy)benzoyl]diphenyl ether, 4,4'-bis[3-(3-aminophenoxy)benzoyl]diphenyl ether, 4,4'-bis[4-(4-amino-α,α-dimethylbenzyl)phenoxy]dibenzophenone, 4,4'-bis[4-(4-amino 1,4-bis[4-(4-aminophenoxy)phenoxy-α,α-dimethylbenzene]benzene, 1,3-bis[4-(4-amino-6-trifluoromethylphenoxy)-α,α-dimethylbenzyl]benzene, 1,3-bis[4-(4-amino-6-fluorophenoxy)-α,α-dimethylbenzyl]benzene, 1,3-bis[4-(4-amino-6-methylphenoxy)-α,α-dimethylbenzyl]benzene, 1,3-bis[4-(4-amino-6-methylphenoxy)-α,α-dimethylbenzyl]benzene, diphenyl]benzene, 1,3-bis[4-(4-amino-6-cyanophenoxy)-α,α-dimethylbenzyl]benzene, 3,3'-diamino-diphenoxybenzophenone, 4,4'-diamino-5,5'-diphenoxybenzophenone, 3,4'-diamino-4,5'-diphenoxybenzophenone, 3,3'-diamino-4-phenoxybenzophenone, 4,4'-diamino-5-phenoxybenzophenone, 3,4'-diamino-4-phenoxybenzophenone, 3,4'-diamino-5'-phenoxybenzophenone, 3,3'-diamino-4,4'-Dibiphenoxybenzophenone, 4,4'-diamino-4,5'-dibiphenoxybenzophenone, 3,4'-diamino-4,4'-dibiphenoxybenzophenone, 3,3'-diamino-4-biphenoxybenzophenone, 4,4'-diamino-5-biphenoxybenzophenone, 4,4'-diamino-4-biphenoxybenzophenone, 3,4'-diamino-5'-biphenoxybenzophenone, 1,3-bis(3-amino-4-phenoxybenzoyl)benzene, 1,4-bis(3-amino-4-phenoxybenzoyl)benzene, 1,3-bis(4-amino-5-phenoxybenzoyl)benzene, 1,4-bis(4-amino-5-phenoxybenzoyl)benzene, 1,3-bis(3-amino-4-phenoxybenzoyl)benzene, 1,4-bis(3-amino-4-biphenoxybenzoyl)benzene, 1,3-bis(3-amino-5-biphenoxybenzoyl)benzene, 1,4-bis(3-amino-5-biphenoxybenzoyl)benzene, 2,6-bis[4-(4-amino-α,α-dimethylbenzyl)phenoxy]benzonitrile, 6,6'-bis(2-aminophenoxy)-3,3,3',3'-tetramethyl-1,1'-spiroidine, 6,6'-bis(3-aminophenoxy)-3,3,3',3'-tetramethyl-1,1'-spiroidine, 6,6'-bis(4-aminophenoxy)-3,3,3',3'-tetramethyl-1,1'-spiroidine, and the like.

[0044] These diamines can be used alone or in combination of two or more. Among these, 1,3-bis(4-aminophenoxy)benzene and 4,4'-bis(4-aminophenoxy)biphenyl are most suitable.

[0045] The tetracarboxylic dianhydride component used in the thermoplastic polyimide resin obtained by dehydrating and cyclizing the polyamic acid obtained by reacting a diamine component with a tetracarboxylic dianhydride can be a monocyclic aromatic group having one benzene ring, a condensed polycyclic aromatic group having a naphthalene ring or the like, or a tetracarboxylic dianhydride having a crosslinking member of a carbonyl group, a sulfone group, a sulfoxide group, an ether group or a sulfide group, in which a plurality of aromatic groups are directly bonded. For example, the tetracarboxylic dianhydride described in JP-A-2004-27137 and JP-A-4629894 can be used as the tetracarboxylic dianhydride component.

[0046] Specific examples of the tetracarboxylic dianhydride component include the following tetracarboxylic dianhydrides. That is, ethylene tetracarboxylic dianhydride, cyclopentane tetracarboxylic dianhydride, 3,3',4,4'-benzophenone tetracarboxylic dianhydride, 2,3,3',4'-benzophenone tetracarboxylic dianhydride, 2,2',3,3'-benzophenone tetracarboxylic dianhydride, 3,3',4,4'-biphenyl tetracarboxylic dianhydride, 2,2',3,3'-biphenyl tetracarboxylic dianhydride, 2,2-bis(2,3-dicarboxyphenyl)propane dianhydride, bis(3,4-dicarboxyphenyl)ether dianhydride, bis(3,4-dicarboxyphenyl)sulfone dianhydride, 1,1-bis(2,3-dicarboxyphenyl)ethane dianhydride, bis(2,3-dicarboxyphenyl)methane dianhydride, bis(3,4-dicarboxyphenyl)methane dianhydride, 2,2'-bis(3,4-dicarboxyphenyl)-1,1,3,3,3-heptane dianhydride, Hexafluoropropane dianhydride, pyromellitic dianhydride, 1,4-difluoropyromellitic acid, 1,4-bis(3,4-dicarboxytrifluorophenoxy)tetrafluorobenzene dianhydride, 2,2'-bis[4-(3,4-carboxyphenoxy)benzene]-1,1,1,3,3,3-hexafluoropropane dianhydride, 2,3,6,7-naphthalenetetracarboxylic dianhydride, 1,4,5,8-naphthalenetetracarboxylic acid Examples of the dianhydride include 1,2,5,6-naphthalenetetracarboxylic dianhydride, 1,2,3,4-benzenetetracarboxylic dianhydride, 3,4,9,10-perylenetetracarboxylic dianhydride, 2,3,6,7-anthracenetetracarboxylic dianhydride, 1,2,7,8-phenanthrenetetracarboxylic dianhydride, 1,2,3,4-butanetetracarboxylic dianhydride, and 1,2,3,4-cyclobutanetetracarboxylic dianhydride.

[0047] These tetracarboxylic dianhydrides can be used alone or in combination of two or more. Compounds obtained by hydrolyzing all or a part of the above tetracarboxylic dianhydrides can also be used. Among these, pyromellitic dianhydride and 3,3',4,4'-biphenyltetracarboxylic dianhydride are preferred. These tetracarboxylic dianhydrides can be used alone or in combination of two or more.

[0048] When the diamine component is 4,4'-bis(3-aminophenoxy)biphenyl, the tetracarboxylic dianhydride component is preferably combined with pyromellitic dianhydride, and when the diamine component is 1,3-bis(4-aminophenoxy)benzene, the tetracarboxylic dianhydride component is preferably 3,3',4,4'-biphenyltetracarboxylic dianhydride.

[0049] Thermoplastic polyimide resins having repeating structural units of 4,4'-bis(3-aminophenoxy)biphenyl and pyromellitic dianhydride [Structural formula (3)] are suitable because they are excellent in the moldability, heat resistance, mechanical properties, electrical insulation properties, creep resistance, chemical resistance, low water absorption, etc. A specific example of a thermoplastic polyimide having repeating structural units of 4,4'-bis(3-aminophenoxy)biphenyl and pyromellitic dianhydride is the Aurum series (product name, manufactured by Mitsui Chemicals, Inc.) in U.S. Patent No. 5,043,419.

[0050] [ka]

[0051] The Tm of the thermoplastic polyimide resin having repeating structural units of 4,4'-bis(3-aminophenoxy)biphenyl and pyromellitic dianhydride is 350°C or more and 450°C or less, preferably 370°C or more and 420°C or less, more preferably 380°C or more and 400°C or less, and even more preferably 385°C or more and 395°C or less. This is because if the Tm exceeds 450°C, the load on the melt extrusion molding machine 20 increases, making it difficult to mold the resin film. The Tm (unit: °C) of the crystalline thermoplastic polyimide resin consisting of 4,4'-bis(3-aminophenoxy)biphenyl and pyromellitic dianhydride can be determined by thermal analysis using a differential scanning calorimeter.

[0052] The apparent melt viscosity of a thermoplastic polyimide resin having repeating structural units of 4,4'-bis(3-aminophenoxy)biphenyl and pyromellitic dianhydride was measured using a constant-load extrusion capillary rheometer with a die of 1.0 mm in diameter and 10 mm in length under the conditions of a temperature of 390°C and a load of 50 kgf. 1 Pa·s or more 5.0×10 4 Pa s or less, preferably 1.0×10 2 Pa·s or more 1.0×10 4 Pa s or less, preferably 2.5×10 2 Pa·s or more 7.5×10 3 Pa s or less, more preferably 2.5×10 2 Pa·s or more 5.0×10 3 The range is set to Pa·s or less.

[0053] This is because the apparent melt viscosity is 1.0×10 2 If it is less than Pa·s, the melt tension of the crystalline thermoplastic polyimide resin having repeating structural units of molten 4,4'-bis(3-aminophenoxy)biphenyl and pyromellitic dianhydride is small, and problems occur in the formability of the resin film when it is melt extruded. 4 If it exceeds Pa·s, too much load is placed on the melt extruder 20, making it difficult to form a good resin film by melt extrusion.

[0054] Examples of the crystalline thermoplastic polyimide resin include the above-mentioned crystalline thermoplastic polyimide resins, as well as crystalline thermoplastic polyimide resins composed of a diamine component mainly composed of an aliphatic diamine component and a tetracarboxylic acid component.

[0055] It is important that the diamine component of such a crystalline thermoplastic polyimide resin is mainly composed of an aliphatic diamine component (including alicyclic diamine). That is, it is important that more than 50 mol% of the diamine component is an aliphatic diamine, preferably 60 mol% or more, more preferably 80 mol% or more, and particularly preferably 90 mol% or more. In particular, it is optimal that all of the diamine components (100 mol%) are aliphatic diamines. By using an aliphatic diamine as the main component, it is possible to impart excellent heat resistance, low water absorption, moldability, and secondary processability to the thermoplastic polyimide resin film 10.

[0056] The aliphatic diamine contained in the diamine component is not particularly limited as long as it is a diamine component having amine groups at both ends of a hydrocarbon, but when heat resistance is important, it is preferable to include an alicyclic diamine having amine groups at both ends of a cyclic hydrocarbon. The carbon number of this alicyclic diamine is preferably 6 to 22, and specific examples include 1,2-bis(aminomethyl)cyclohexane, 1,3-bis(aminomethyl)cyclohexane, 1,4-bis(aminomethyl)cyclohexane, 1,2-cyclohexanediamine, 1,3-cyclohexanediamine, 1,4-cyclohexanediamine, 4,4'-diaminodicyclohexylmethane, 4,4'-methylenebis(2-methylcyclohexylamine), carvonediamine, isophoronediamine, norbornanediamine, bis(aminomethyl)tricyclodecane [5.2.1.0 2.6]decane, 3,3,'-dimethyl-4,4'-diaminodicyclohexylmethane, 4,4'-diaminodicyclohexylpropane, etc. Among these, 1,3-bis(aminomethyl)cyclohexane is the most suitable from the viewpoint of achieving both heat resistance, moldability, and secondary processability.

[0057] When emphasis is placed on the formability and secondary processability of the crystalline thermoplastic polyimide resin film 10, it is preferable that the aliphatic diamine contained in the diamine component contains a linear aliphatic diamine having amine groups at both ends of a linear hydrocarbon. There are no particular limitations on this linear aliphatic diamine as long as it is a diamine component having an alkyl group at both ends with amino groups, and specific examples include ethylenediamine (carbon number 2), propylenediamine (carbon number 3), butanediamine (carbon number 4), pentadiamine (carbon number 5), hexanediamine (carbon number 6), heptanediamine (carbon number 7), octanediamine (carbon number 7), octanediamine (carbon number 8), nonanediamine (carbon number 9), decanediamine (carbon number 10), undecanediamine, and ethylenediamine (carbon number 11). Examples include amine (carbon number 11), dodecanediamine (carbon number 12), tridecanediamine (carbon number 13), tetradecanediamine (carbon number 14), pentadecanediamine (carbon number 15), hexadecanediamine (carbon number 16), heptadecanediamine (carbon number 17), octadecanediamine (carbon number 18), nonadecanediamine (carbon number 19), eicosane (carbon number 20), triacontane (carbon number 30), tetracontane (carbon number 40), and pentacontane (carbon number 50).

[0058] Among these, from the viewpoints of excellent moldability, secondary processability, and low water absorption, linear aliphatic diamines having 4 to 12 carbon atoms are optimal. These linear aliphatic diamines may also have a branched structure having 1 to 10 carbon atoms.

[0059] The diamine component may contain other diamine components other than the aliphatic diamine, specifically, 1,4-phenylenediamine, 1,3-phenylenediamine, 2,4-phenylenediamine, 2,4-toluenediamine, 4,4'-diaminodiphenylether, 3,4'-diaminodiphenylether, 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, and α,α'-bis(3-aminophenyl)-1,4-diisopropylbenzene. Examples of such diamine components include aromatic diamine components such as 2,2-bis[4-(4-aminophenoxy)phenyl]propane, 4,4'-diaminodiphenyl 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.

[0060] The diamine component may contain at least one of an alicyclic diamine and a linear aliphatic diamine, but it is preferable to contain both an alicyclic diamine and a linear aliphatic diamine because it has an excellent balance between heat resistance and moldability. When both an alicyclic diamine and a linear aliphatic diamine are contained, the respective contents are preferably in the range of alicyclic diamine: linear aliphatic diamine=99:1 to 1:99 mol%, more preferably 80:20 to 20:80 mol%, and optimally 60:40 to 40:60 mol%. This is because, if the ratio of the alicyclic diamine and the linear aliphatic diamine contained in the diamine component is within the range, the balance between heat resistance and moldability of the thermoplastic polyimide resin film 10 can be improved.

[0061] Examples of the tetracarboxylic acid component of the crystalline thermoplastic polyimide resin include cyclobutane-1,2,3,4-tetracarboxylic acid, cyclopentane-1,2,3,4-tetracarboxylic acid, cyclohexane-1,2,3,5-tetracarboxylic acid, 3,3',4,4'-benzophenonetetracarboxylic acid, biphenyltetracarboxylic acid, naphthalene-1,4,5,8-tetracarboxylic acid, naphthalene-1,4-tetracarboxylic acid, pyromellitic acid, etc. Also, alkyl esters of these can be used.

[0062] Among these, it is preferable that more than 50 mol% of the tetracarboxylic acid component is pyromellitic acid. This is because if the tetracarboxylic acid component is mainly composed of pyromellitic acid, heat resistance, secondary processability, and low water absorption are improved. From this viewpoint, it is preferable that the tetracarboxylic acid component is 60 mol% or more, more preferably 80 mol% or more, and even more preferably 90 mol% or more. In particular, it is optimal that all of the tetracarboxylic acid components (100 mol%) are pyromellitic acid.

[0063] The Tm of the thermoplastic polyimide resin is 300°C or more and 370°C or less, preferably 310°C or more and 350°C or less, more preferably 320°C or more and 350°C or less, and even more preferably 310°C or more and 330°C or less. This is because if the Tm is less than 300°C, it is not possible to obtain a thermoplastic polyimide resin film 10 having heat resistance. On the other hand, if the melting point of the crystalline thermoplastic polyimide resin exceeds 370°C, the melt extruder 20 is overloaded, making it difficult to manufacture a thermoplastic polyimide resin film 10 having good crystallinity by melt extrusion molding, and further, problems such as limitations on the melt extruder 20 that can be used arise. The Tm of the crystalline thermoplastic polyimide resin can be determined by thermal analysis using a differential scanning calorimeter, as described above.

[0064] The apparent melt viscosity of a crystalline thermoplastic polyimide resin consisting of a diamine component mainly composed of an aliphatic diamine component and a tetracarboxylic acid component is 5.0×10 when measured by a constant load extrusion type capillary rheometer using a die having a diameter of 1.0 mm and a length of 10 mm under conditions of a temperature of 350°C and a load of 50 kgf. 1 Pa·s or more 5.0×10 4 Pa s or less, preferably 1.0×10 2 Pa·s or more 1.0×10 4 Pa s or less, preferably 2.5×10 2 Pa·s or more 7.5×10 3 Pa s or less, more preferably 2.5×10 2 Pa·s or more 5.0×10 3 The range is set to Pa·s or less.

[0065] This is because the apparent melt viscosity is 1×10 2 If it is less than 5.0×10 Pa·s, the melt tension of the molten crystalline thermoplastic polyimide resin is low, which causes problems in the formability of the resin film by melt extrusion molding. 4 If it exceeds Pa·s, too much load is placed on the melt extruder 20, making it difficult to form a good resin film by melt extrusion.

[0066] As the crystalline thermoplastic polyimide resin, a random copolymer, an alternating copolymer, a block copolymer, a graft copolymer, or a modified product with other copolymerizable monomers can be used as long as the effect of the present invention is not impaired. The shape of the crystalline thermoplastic polyimide resin may be any shape such as powder, flake, pellet, block, etc.

[0067] The crystalline thermoplastic polyimide resin is not particularly limited, but is preferably the crystalline thermoplastic polyimide resin described in Japanese Patent No. 5365762, Japanese Patent No. 6024859, Japanese Patent No. 6037088, or Japanese Patent No. 6394662, and more preferably the crystalline thermoplastic polyimide resin described in Japanese Patent No. 6024859, Japanese Patent No. 6037088, or Japanese Patent No. 6394662. Specific examples of such crystalline thermoplastic polyimide resins include the Surprim series (product name, manufactured by Mitsubishi Gas Chemical Co., Ltd.), which has high strength, high heat resistance, high solvent resistance, crystallinity, and excellent film moldability.

[0068] The molding material M of the thermoplastic polyimide resin film 10 may be, in addition to thermoplastic polyimide resin, polyethylene (PE) resin, polypropylene (PP) resin, polymethylpentene (PMP) resin, polystyrene (PS) resin, and other polyolefin resins, acid-modified olefin resins, such as maleic anhydride-modified polyethylene resin and maleic anhydride-modified polypropylene resin, polyethylene terephthalate (PET) resin, polybutylene terephthalate (PBT) resin, polyethylene naphthalate (PEN) resin, and other polyester resins, polyamide-imide (PAI) resin, etc. Resin, polyamide resins such as polyamide 4T (PA4T) resin, polyamide 6T (PA6T) resin, modified polyamide 6T (modified PA6T) resin, polyamide 9T (PA9T) resin, polyamide 10T (PA10T) resin, polyamide 11T (PA11T) resin, polyamide 6 (PA6) resin, polyamide 66 (PA66) resin, and polyamide 46 (PA46) resin, polysulfone resins such as polysulfone (PSU) resin, polyethersulfone (PES) resin, and polyphenylene sulfone (PPSU) resin, polyphenylene sulfide (PPS) resin polyarylene sulfide resins such as polyphenylene sulfide ketone resin, polyphenylene sulfide sulfone resin, and polyphenylene sulfide ketone sulfone resin; polyarylene ether ketone (PAEK) resins such as polyether ketone (PEK) resin, polyether ketone ketone (PEKK) resin, polyether ether ketone ketone (PEEKK) resin, and polyether ketone ether ketone ketone (PEKEKK) resin; polytetrafluoroethylene (PTFE) resin; and polytetrafluoroethylene-perfluoroalkyl Vinyl ether copolymer (PFA) resin, tetrafluoroethylene-hexafluoropropyl copolymer (FEP) resin, tetrafluoroethylene-ethylene copolymer (ETFE) resin, polychlorotrifluoroethylene (PCTFE) resin, polyvinylidene fluoride (PVdF) resin, vinylidene fluoride-tetrafluoroethylene-hexafluoropropylene copolymer resin, acid-modified fluororesin and other fluororesins, polycarbonate (PC) resin, polyarylate (PAR) resin, polyacetal (POM) resin, liquid crystal polymer (LCP),Thermoplastic resins such as aliphatic polyketone resins can be optionally added.

[0069] In addition to the thermoplastic polyimide resin, various additives such as crystal nucleating agents, antioxidants, heat stabilizers, lubricants, plasticizers, antistatic agents, antiblocking agents, fillers, viscosity modifiers, and coloring inhibitors can be added to the molding material M of the thermoplastic polyimide resin film 10 within the scope of the present invention. In addition, the thermoplastic polyimide resin of the molding material M can contain particles, and in this case, inorganic particles and organic particles are preferably used. Examples of inorganic particles include metal oxides such as silica, alumina, titanium dioxide, and zirconia, barium sulfate, calcium carbonate, aluminum silicate, calcium phosphate, mica, talc, kaolin, clay, and zeolite. Among these, metal oxides such as silica, alumina, titanium dioxide, and zirconia, and calcium carbonate are preferred.

[0070] In contrast, the organic particles may be one of dimethylpolysiloxane crosslinked particles, polymethoxysilane compound crosslinked particles, polyorganosilsesquioxane cured fine powder, polystyrene compound crosslinked particles, acrylic compound crosslinked particles, polyurethane compound crosslinked particles, polyester compound crosslinked particles, fluorine compound crosslinked particles, carbon nanotubes, graphene, and fullerene, which may be used alone or in combination of two or more.

[0071] The average particle size of the inorganic particles and the organic particles is preferably in the range of 0.01 μm to 5.0 μm. The average particle size is preferably in the range of 0.05 μm to 3.0 μm, more preferably 0.07 μm to 2.0 μm, and further preferably 0.1 μm to 1.0 μm. This is because, if the average particle size is less than 0.01 μm, the particles will aggregate, the dispersibility in the thermoplastic polyimide resin will decrease, the mechanical properties of the thermoplastic polyimide resin film 10 will decrease, the film will become easily cracked or broken during folding processing, and the handling properties will decrease.

[0072] On the other hand, if it exceeds 5.0 μm, the mechanical properties of the thermoplastic polyimide resin film 10 will decrease, making it more likely to crack or break during bending, or causing deterioration in electrical insulation properties and water absorption. Methods for measuring the average particle size of inorganic particles and organic particles include a method in which the weight average diameter is calculated using the circle equivalent diameter obtained by image processing of a transmission electron microscope photograph of the particles.

[0073] By adding the inorganic particles or organic particles, the surface of the thermoplastic polyimide resin film 10 can be roughened, and the slipperiness of the thermoplastic polyimide resin film 10 can be improved.

[0074] The amount of inorganic particles and organic particles added is preferably 0.01 parts by mass or more and 10 parts by mass or less, preferably 0.1 parts by mass or more and 8.0 parts by mass or less, more preferably 0.5 parts by mass or more and 5.0 parts by mass or less, and even more preferably 1.0 parts by mass or more and 3.0 parts by mass or less, when the thermoplastic polyimide resin is 100 parts by mass. This is because if the amount added is less than 0.01 parts by mass, the handling properties are insufficient. On the other hand, if the amount added exceeds 10 parts by mass, the mechanical properties of the thermoplastic polyimide resin film 10 are reduced, so that the thermoplastic polyimide resin film 10 may be torn or cracked during folding processing of the thermoplastic polyimide resin film 10.

[0075] Furthermore, if the amount of inorganic particles or organic particles added is within the range of 0.01 parts by mass or more and 10 parts by mass or less, deterioration in the quality of the thermoplastic polyimide resin film due to the generation of die gunk can be prevented. To explain this in more detail, when the thermoplastic polyimide resin film 10 is molded into a film using the die 23 shown in FIG. 5, a large amount of deposits called die gunk may adhere and accumulate at the exit (also called the die lip) of the die 23. If such die gunk accumulates, a die line may be formed in the thermoplastic polyimide resin film 10, or the die gunk may leave the exit of the die 23 and be mixed into the thermoplastic polyimide resin film 10, resulting in deterioration in the quality of the thermoplastic polyimide resin film 10.

[0076] According to this embodiment, the amount of inorganic particles or organic particles added is within the range of 0.01 parts by mass or more and 10 parts by mass or less, so that it is possible to effectively prevent the occurrence of die lines in the thermoplastic polyimide resin film 10 and the infiltration of die gunk into the thermoplastic polyimide resin film 10, which would result in a deterioration in quality.

[0077] In order to prevent aggregation of inorganic particles or organic particles or to improve affinity with thermoplastic polyimide resin, a silane coupling agent such as vinyltrimethoxysilane, vinyltriethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-aminopropylethoxysilane, p-styryltrimethoxysilane, 3-methacryloxypropylmethyldimethacrylate, etc. may be added to the inorganic particles or organic particles within a range that does not impair the properties of the thermoplastic polyimide resin film 10. xysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-acryloxypropyltrimethoxysilane, tris-(trimethoxysilylpropyl)isocyanurate, 3-ureidopropyltrialkoxysilane, 3-mercaptopropylmethyldimethoxysilane, 3-isocyanatopropyltriethoxysilane, 3-trimethoxysilylpropylsuccinic anhydride, imidazole silane, etc.], titanate-based coupling agents [isopropyltrimethoxysilane, sostearoyl titanate, isopropyl (dioctyl pyrophosphate) titanate, isopropyl tris(N-aminoethyl-aminoethyl) titanate, tetraoctyl bis(di-tridecyl phosphite) titanate, tetra(2,2-diallyloxymethyl-1-butyl) bis(di-tridecyl) phosphite titanate, bis(dioctyl pyrophosphate) oxyacetate titanate, bis(dioctyl pyrophosphate) ethylene titanate, isopropyl trioctanoyl titanate It is possible to treat the resin with various coupling agents such as isopropyl dimethacryl isostearoyl titanate, isopropyl tridecylbenzenesulfonyl titanate, isopropyl isostearoyl diacryl titanate, isopropyl tri(dioctyl phosphate) titanate, isopropyl tricumyl phenyl titanate, tetraisopropyl (dioctyl phosphite) titanate, and aluminate coupling agents such as acetoalkoxyaluminum diisopropylate.

[0078] The amount of the coupling agent to be treated is preferably in the range of 0.01 to 5.0 parts by mass, preferably 0.1 to 3.0 parts by mass, more preferably 0.5 to 2.0 parts by mass, and even more preferably 0.5 to 1.5 parts by mass, when the inorganic particles or organic particles are taken as 100 parts by mass. This is because, when the amount added is less than 0.01 parts by mass, if the particles cannot be prevented from agglomerating, it may not be possible to improve the affinity to the thermoplastic polyimide resin, and the dispersibility in the thermoplastic polyimide resin may decrease, resulting in a decrease in mechanical properties.

[0079] On the other hand, if the amount exceeds 5.0 parts by mass, the excessive addition of the coupling agent causes the inorganic and organic particles to become sticky and the particles to aggregate together, and when added to a thermoplastic polyimide resin, the mechanical properties of the thermoplastic polyimide resin film 10 decrease. Also, the coupling agent may seep out of the thermoplastic polyimide resin film 10 and contaminate the slots 5 and the conductive windings 6.

[0080] Examples of the molding method of the thermoplastic polyimide resin film 10 include melt extrusion molding, calendar molding, casting, etc. Among these molding methods, the melt extrusion molding method capable of continuously extruding the thermoplastic polyimide resin film 10 into a strip shape is optimal from the viewpoints of the thickness accuracy of the thermoplastic polyimide resin film 10, productivity of thick films, improved handleability, and simplification of equipment.

[0081] In the melt extrusion molding method, as shown in FIG. 5, a melt extrusion molding machine 20 is used to melt and knead a molding material M containing a thermoplastic polyimide resin, and the molten thermoplastic polyimide resin is continuously extruded in a strip shape from a die 23 such as a T-die or a round die connected to the tip of the melt extrusion molding machine 20, and the thermoplastic polyimide resin is sandwiched between a pair of pressure rollers 27 and a plurality of cooling rollers 28 and cooled, thereby producing a thermoplastic polyimide resin film 10.

[0082] The melt extrusion molding machine 20 is composed of, for example, a single-screw extrusion molding machine or a twin-screw extrusion molding machine, and has a raw material inlet 21 for the molding material M disposed at the upper rear portion. This raw material inlet 21 is connected to an inert gas supply pipe 22 which supplies an inert gas such as helium gas, neon gas, argon gas, krypton gas, nitrogen gas, etc. as needed. The supply of inert gas from this inert gas supply pipe 22 effectively prevents oxidative deterioration, oxygen crosslinking, and thermal crosslinking of the molding material M.

[0083] The melting temperature during melt kneading in the melt extrusion molding machine 20 is not particularly limited as long as it is a temperature at which melt kneading and dispersion are possible and the thermoplastic polyimide resin does not decompose. In the case of an amorphous thermoplastic polyimide resin, however, it is preferable that the melting temperature be in the range of Tg or higher and lower than the thermal decomposition temperature of the amorphous polyimide resin.

[0084] On the other hand, in the case of a crystalline thermoplastic polyimide resin, the range between the Tm of the crystalline thermoplastic polyimide resin and the thermal decomposition temperature of the crystalline thermoplastic polyimide resin is preferable. This is because, if the temperature is below the Tg of the amorphous thermoplastic polyimide resin or below the Tm of the crystalline thermoplastic polyimide resin, the thermoplastic polyimide resin does not have melt fluidity, and therefore the thermoplastic polyimide resin film 10 cannot be formed by melt extrusion molding. If the temperature is above the thermal decomposition temperature of the amorphous thermoplastic polyimide resin or the crystalline thermoplastic polyimide resin, the thermoplastic polyimide resin will be decomposed.

[0085] The melting temperature of the amorphous thermoplastic polyimide resin is preferably in the range of [Tg of the amorphous thermoplastic polyimide resin + 80] ° C. or more and [Tg of the amorphous thermoplastic polyimide resin + 200] ° C. or less, more preferably in the range of [Tg of the amorphous thermoplastic polyimide resin + 100] ° C. or more and [Tg of the amorphous thermoplastic polyimide resin + 185] ° C. or less, and even more preferably in the range of [Tg of the amorphous thermoplastic polyimide resin + 130] ° C. or more and [Tg of the amorphous thermoplastic polyimide resin + 170] ° C. The Tg (unit: ° C.) of the amorphous thermoplastic polyimide resin can be determined by thermal analysis using a differential scanning calorimeter, as described above.

[0086] The melting temperature of the crystalline thermoplastic polyimide resin is preferably from [Tm of the crystalline thermoplastic polyimide resin + 10]° C. to [Tm of the crystalline thermoplastic polyimide resin + 100]° C., more preferably from [Tm of the crystalline thermoplastic polyimide resin + 20]° C. to [Tm of the crystalline thermoplastic polyimide resin + 70]° C., and even more preferably from [Tm of the crystalline thermoplastic polyimide resin + 30]° C. to [Tm of the crystalline thermoplastic polyimide resin + 60]° C. The Tm (unit:° C.) of the crystalline thermoplastic polyimide resin can also be determined by thermal analysis using a differential scanning calorimeter, as described above.

[0087] The die 23 is connected to the tip of the melt extruder 20 via a connecting pipe 24, and functions to continuously extrude the molten thermoplastic polyimide resin molded into a strip shape downward. There are various types of this die 23, but a T-die is optimal because it is possible to obtain the thermoplastic polyimide resin film 10 with excellent thickness accuracy. A gear pump 25 and a polymer filter 26 are preferably attached to the connecting pipe 24 upstream of the die 23.

[0088] The gear pump 25 functions to transfer the molding material M melt-kneaded by the melt extruder 20 at a constant flow rate and with high precision to the downstream die 23 via the polymer filter 26. In addition, the polymer filter 26 functions to separate unmelted thermoplastic polyimide resin and foreign matter from the thermoplastic polyimide resin in a molten state, and transfer the thermoplastic polyimide resin in a molten state to the die 23.

[0089] In the case of an amorphous thermoplastic polyimide resin, the temperature during extrusion through the die 23 is preferably in the range of Tg or higher and lower than the thermal decomposition temperature of the amorphous thermoplastic polyimide resin, whereas in the case of a crystalline thermoplastic polyimide resin, the temperature is preferably in the range of Tm or higher and lower than the thermal decomposition temperature of the crystalline thermoplastic polyimide resin.

[0090] This is because, when the temperature is less than the Tg of the amorphous thermoplastic polyimide resin or less than the Tm of the crystalline thermoplastic polyimide resin, the thermoplastic polyimide resin does not have melt fluidity, and therefore it is not possible to form the thermoplastic polyimide resin film 10 by melt extrusion molding. Also, when the temperature is equal to or higher than the thermal decomposition temperature of the amorphous thermoplastic polyimide resin or the crystalline thermoplastic polyimide resin, the thermoplastic polyimide resin is decomposed, which is undesirable.

[0091] The temperature at which the amorphous thermoplastic polyimide resin is extruded through the die 23 is preferably in the range of [Tg of the amorphous thermoplastic polyimide resin + 80]°C or higher and [Tg of the amorphous thermoplastic polyimide resin + 200]°C or lower, more preferably in the range of [Tg of the amorphous thermoplastic polyimide resin + 100]°C or higher and [Tg of the amorphous thermoplastic polyimide resin + 185]°C or lower, and even more preferably in the range of [Tg of the amorphous thermoplastic polyimide resin + 130]°C or higher and [Tg of the amorphous thermoplastic polyimide resin + 170]°C or lower.

[0092] In contrast, the extrusion temperature of the die 23 for the crystalline thermoplastic polyimide resin is preferably from [Tm of the crystalline thermoplastic polyimide resin + 10°C] to [Tm of the crystalline thermoplastic polyimide resin + 100°C], more preferably from [Tm of the crystalline thermoplastic polyimide resin + 20°C] to [Tm of the crystalline thermoplastic polyimide resin + 70°C], and even more preferably from [Tm of the crystalline thermoplastic polyimide resin + 30°C] to [Tm of the crystalline thermoplastic polyimide resin + 60°C].

[0093] Below the die 23, a pair of pressure rolls 27 facing each other with a gap therebetween are rotatably supported, and between the pair of pressure rolls 27, a plurality of cooling rolls 28 arranged in a row and in sliding contact with each other are rotatably supported, and among the plurality of cooling rolls 28, the upstream cooling roll 28 and the downstream cooling roll 28 each slide in contact with the circumferential surface of the pressure roll 27. Each pressure roll 27 is configured to have a reduced diameter, and each cooling roll 28 is configured to have a larger diameter than the pressure roll 27.

[0094] Of the pair of pressure-bonding rolls 27, a winder 30 is installed downstream of the downstream pressure-bonding roll 27, which winds up the thermoplastic polyimide resin film 10 around a rotatable winding tube 29. Between this winder 30 and the downstream pressure-bonding roll 27, a slit blade 31 is arranged to be able to rise and fall, which forms a slit in the longitudinal direction of the side of the thermoplastic polyimide resin film 10. Between this slit blade 31 and the winder 30, a required number of tension rolls 32 are rotatably supported on a shaft for applying tension to the thermoplastic polyimide resin film 10 to smoothly wind it up.

[0095] When the thermoplastic polyimide resin of the molding material M is an amorphous thermoplastic polyimide resin, each pressing roll 27 is adjusted to a temperature of not less than [Tg of the amorphous thermoplastic polyimide resin - 200°C] and not more than [Tg of the amorphous thermoplastic polyimide resin + 100°C], preferably not less than [Tg of the amorphous thermoplastic polyimide resin - 150°C] and not more than [Tg of the amorphous thermoplastic polyimide resin + 50°C], more preferably not less than [Tg of the amorphous thermoplastic polyimide resin - 100°C] and not more than [Tg of the amorphous thermoplastic polyimide resin], and even more preferably not less than [Tg of the amorphous thermoplastic polyimide resin - 70°C] and not more than [Tg of the amorphous thermoplastic polyimide resin], and is pressed against the cooling roll 28 while being in sliding contact with the amorphous thermoplastic polyimide resin.

[0096] The reason why the temperature of the pressure bonding roll 27 is within this range is that if the temperature is below [Tg of the amorphous thermoplastic polyimide resin - 200°C], the extruded strip of amorphous thermoplastic polyimide resin cannot be brought into close contact with the cooling roll 28, making it impossible to obtain a smooth thermoplastic polyimide resin film 10. On the other hand, if the temperature exceeds [Tg of the amorphous thermoplastic polyimide resin + 100°C], there is a risk that the resin will stick to the pressure bonding roll 27 and break.

[0097] When the thermoplastic polyimide resin of the molding material M is a crystalline thermoplastic polyimide resin, each pressure-bonding roll 27 is adjusted to a temperature range of not less than [Tg of the crystalline thermoplastic polyimide resin - 100°C] and not more than Tm of the crystalline thermoplastic polyimide resin, preferably not less than [Tg of the crystalline thermoplastic polyimide resin - 50°C] and not more than [Tm of the crystalline thermoplastic polyimide resin - 50°C], more preferably not less than [Tg of the crystalline thermoplastic polyimide resin] and not more than [Tm of the crystalline thermoplastic polyimide resin - 100°C]°C, and even more preferably not less than [Tg of the crystalline thermoplastic polyimide resin] and not more than [Tm of the thermoplastic polyimide resin - 120°C], and is brought into sliding contact with the crystalline thermoplastic polyimide resin film 10 and pressed against the cooling roll 28.

[0098] The reason why the temperature of the pressure roller 27 is within this range is that if the temperature is below [Tg-100 of the crystalline thermoplastic polyimide resin]°C, the melt-extruded strip-shaped crystalline thermoplastic polyimide resin cannot be brought into close contact with the cooling roller 28, and therefore a smooth thermoplastic polyimide resin film 10 cannot be obtained. On the other hand, if the temperature exceeds the Tm of the crystalline thermoplastic polyimide resin, the resin may stick to the pressure roller 27 and break. Methods for adjusting the temperature of the pressure roller 27 include, for example, a method using a heat medium such as air, water, or oil, a method using an electric heater, and a method using induction heating.

[0099] From the viewpoint of improving the adhesion between the thermoplastic polyimide resin and the cooling roll 28, the peripheral surface of each pressure roll 27 is coated with a rubber layer made of at least natural rubber, isoprene rubber, butadiene rubber, norbornene rubber, acrylonitrile butadiene rubber, nitrile rubber, urethane rubber, silicone rubber, fluororubber or the like as necessary, and inorganic compounds such as silica and alumina are selectively added to this rubber layer. Among these rubbers, silicone rubber and fluororubber, which have excellent heat resistance, are optimally selected.

[0100] The multiple cooling rolls 28 are, for example, metal rolls with a larger diameter than the compression roll 27, and are rotatably supported below the die 23 to clamp the extruded thermoplastic polyimide resin between the peripheral surface of the compression roll 27 and cool the thermoplastic polyimide resin together with the compression roll 27 to form a thermoplastic polyimide resin film 10, and function to control the thickness of this thermoplastic polyimide resin film 10 within a predetermined range.

[0101] For the same reasons as for the pressing roll 27, when the molding material M contains an amorphous thermoplastic polyimide resin, each cooling roll 28 is adjusted to a temperature of not less than [Tg of the amorphous thermoplastic polyimide resin - 200°C] and not more than [Tg of the amorphous thermoplastic polyimide resin + 100°C], preferably not less than [Tg of the amorphous thermoplastic polyimide resin - 150°C] and not more than [Tg of the amorphous thermoplastic polyimide resin + 50°C], more preferably not less than [Tg of the amorphous thermoplastic polyimide resin - 100°C] and not more than [Tg of the amorphous thermoplastic polyimide resin], and even more preferably not less than [Tg of the amorphous thermoplastic polyimide resin - 70°C] and not more than [Tg of the amorphous thermoplastic polyimide resin], and is brought into sliding contact with the amorphous thermoplastic polyimide resin and pressed against the adjacent cooling roll 28.

[0102] For the same reasons as for the pressure-bonding roll 27, when the molding material M contains a crystalline thermoplastic polyimide resin, each cooling roll 28 is adjusted to a temperature range of not less than [Tg of crystalline thermoplastic polyimide resin - 100°C] and not more than Tm of the crystalline thermoplastic polyimide resin, preferably not less than [Tg of crystalline thermoplastic polyimide resin - 50°C] and not more than [Tm of crystalline thermoplastic polyimide resin - 50]°C, more preferably not less than [Tg of crystalline thermoplastic polyimide resin] and not more than [Tm of crystalline thermoplastic polyimide resin - 100°C], and even more preferably not less than [Tg of crystalline thermoplastic polyimide resin] and not more than [Tm of crystalline thermoplastic polyimide resin - 120°C], and is brought into sliding contact with the crystalline thermoplastic polyimide resin film 10 and pressure-bonded to the adjacent cooling roll 28.

[0103] As with the pressure roller 27, the temperature of the cooling roller 28 can be adjusted by using a heat transfer medium such as air, water, or oil, an electric heater, or induction heating.

[0104] After the molding material M is extruded into a strip-shaped thermoplastic polyimide resin, this thermoplastic polyimide resin is wound around a pair of pressure bonding rolls 27, multiple cooling rolls 28, a tension roll 32, and a winding tube 29 of a winding machine 30 to form a thermoplastic polyimide resin film 10. After both sides of this thermoplastic polyimide resin film 10 are cut in the longitudinal direction with a slit blade 31, the film is sequentially wound around the winding tube 29 of the winding machine 30, whereby a long thermoplastic polyimide resin film 10 can be produced.

[0105] In producing the thermoplastic polyimide resin film 10, the thermoplastic polyimide resin film 10 may be a smooth film, but it is preferable that at least one of the front and back surfaces has a plurality of fine irregularities that contribute to slipperiness, each of which is approximately cone-shaped in cross section and each of which is approximately hollow truncated cone-shaped. The irregularities may be arranged regularly, such as in a staggered pattern, or irregularly, as necessary.

[0106] Methods for forming a plurality of fine projections and recesses on the thermoplastic polyimide resin film 10 include: (1) forming a fine projection and recess on each of the peripheral surfaces of a pair of pressure rolls 27 and a plurality of cooling rolls 28, and sandwiching the thermoplastic polyimide resin between the pair of pressure rolls 27 and the plurality of cooling rolls 28 to transfer and form the projections and recesses; (2) spraying the thermoplastic polyimide resin film 10 with minute particles of ceramics such as alumina, silicon carbide, zirconia, or glass, inorganic compounds such as stainless steel, minute particles of thermoplastic resins or thermosetting resins such as polycarbonate resin, polyamide resin, acrylic resin, unsaturated polyester resin, urea resin, or melamine resin, minute particles of plants such as wheat or corn, metals such as iron, stainless steel, or zinc, minute particles of molybdenum disulfide, dry ice, or the like; and (3) press-molding the thermoplastic polyimide resin film 10 with a mold having minute projections and recesses to transfer and form the projections and recesses.

[0107] Among these forming methods, the method (1) is the most suitable from the viewpoints of simplifying the equipment, the accuracy of the unevenness size, uniformity and easiness of unevenness formation, and continuous unevenness formation. The forming method (1) is described in more detail as follows: (1-1) a method in which the molten thermoplastic polyimide resin is discharged from the T-die of the melt extrusion molding machine 20 onto a cooling roll 28 having fine unevenness on its peripheral surface, and the discharged material is sandwiched between the cooling roll 28 and a pressure roller 27 having fine unevenness on its peripheral surface, and molded simultaneously with the molding of the thermoplastic polyimide resin film 10; and (1-2) a method in which the molded thermoplastic polyimide resin film 10 is sandwiched between the cooling roll 28 having fine unevenness on its peripheral surface and a pressure roller 27, and an uneven portion is formed. Among these, the forming method (1-1) is the most suitable from the viewpoint of simplifying the equipment.

[0108] The thickness of the thermoplastic polyimide resin film 10 varies depending on the size of the core 4 and the shape of the slots 5, but is preferably 25 μm to 500 μm, more preferably 50 μm to 400 μm, more preferably 75 μm to 300 μm, and even more preferably 100 μm to 250 μm. This is because if the thickness of the thermoplastic polyimide resin film 10 is less than 25 μm, sufficient electrical insulation cannot be obtained, and conversely, if the thickness of the thermoplastic polyimide resin film 10 exceeds 500 μm, the occupancy rate of the conductive windings 6 in the slots 5 decreases, causing problems in miniaturizing the motor 2 and increasing its output.

[0109] The surface roughness (fine unevenness) of the thermoplastic polyimide resin film 10 is 2.0 μm or less and 0.010 μm or more, preferably 1.8 μm or less and 0.012 μm or more, more preferably 1.6 μm or less and 0.013 μm or more, and even more preferably 1.4 μm or less and 0.014 μm or more, in terms of arithmetic mean roughness (Ra) at 23° C. This is because, if the arithmetic mean roughness (Ra) is less than 0.010 μm, the static friction coefficient and dynamic friction coefficient of the thermoplastic polyimide resin film 10 become high, the slipperiness of the thermoplastic polyimide resin film 10 decreases, and wrinkles tend to occur when the thermoplastic polyimide resin film 10 is wound up.

[0110] On the other hand, if the arithmetic mean roughness (Ra) exceeds 2.0 μm, the dielectric breakdown voltage of the thermoplastic polyimide resin film 10 decreases, causing problems in its use as an insulating material, and the strength of the thermoplastic polyimide resin film 10 decreases, which may lead to breakage during molding.

[0111] The slipperiness of the thermoplastic polyimide resin film 10 at 23°C can be evaluated by the slipperiness between the thermoplastic polyimide resin film 10 and a stainless steel plate. From the viewpoint of satisfying mechanical properties, electrical insulation properties, etc., the slipperiness of the thermoplastic polyimide resin film 10 is a static friction coefficient of 0.1 to 0.5, preferably 0.11 to 0.45, more preferably 0.12 to 0.4, and even more preferably 0.14 to 0.35. Also, the dynamic friction coefficient is 0.1 to 0.5, preferably 0.11 to 0.45, more preferably 0.12 to 0.4, and even more preferably 0.14 to 0.35.

[0112] This is because if the static and kinetic friction coefficients are less than 0.10, the sliding properties of the thermoplastic polyimide resin film 10 with the stainless steel plate will decrease, and if the thermoplastic polyimide resin film 10 is used as an insulating material, it will wrinkle, break, crack, or break when inserted into the slot 5, causing problems in its use as an insulating material. Also, if the static and kinetic friction coefficients exceed 0.5, the mechanical properties and dielectric breakdown voltage will decrease, causing problems in its use as an insulating material.

[0113] The electrical insulation properties of the thermoplastic polyimide resin film 10 at 23° C. can be evaluated by the volume resistivity, dielectric breakdown voltage, relative dielectric constant, and dielectric loss tangent. When the thermoplastic polyimide resin film 10 is used as an insulating material for the motor 2, the volume resistivity of the thermoplastic polyimide resin film 10 is 1.0×10 14 If the volume resistivity is Ω·cm or more, excellent insulation properties can be ensured. The volume resistivity of this thermoplastic polyimide resin film 10 can be measured in accordance with JIS C 2139-3-1.

[0114] From the viewpoint of ensuring excellent insulation properties, the volume resistivity of the thermoplastic polyimide resin film 10 at 23° C. is set to 1.0×10 14 Ω cm or more, preferably 1.0×10 14 Ω cm or more 1×10 18 Ω cm or less, preferably 1.0×1015 Ω cm or more 1×10 18 Ω cm or less, more preferably 1.0×10 16 Ω cm or more 1×10 18 Ω cm or less, and more preferably 1.60×10 17 Ω cm or more 4.20×10 17 The upper limit of the volume resistivity is not particularly limited, but the higher the better. It is usually 1×10 18 Ω·cm or less.

[0115] The dielectric breakdown voltage of the thermoplastic polyimide resin film 10 in silicone oil at 23°C is 4 kV or more and 80 kV or less when measured in accordance with IEC 60243-1, but is preferably 4 kV or more and 80 kV or less, more preferably 7 kV or more and 78 kV or less, and even more preferably 20 kV or more and 70 kV or less. This is because if the dielectric breakdown voltage of the silicone oil of the thermoplastic polyimide resin film 10 is less than 4 kV, there is a risk of dielectric breakdown due to surge voltage when the thermoplastic polyimide resin film 10 is used as an insulating material.

[0116] The upper limit of the dielectric breakdown voltage in the silicone oil is preferably as high as possible, and is not particularly limited, but is usually 100 kV or less. This is because if the dielectric breakdown voltage exceeds 80 kV, the thickness of the thermoplastic polyimide resin film 10 exceeds 500 μm, which reduces the occupancy rate of the conductive windings 6 in the slots 5, causing problems in miniaturizing the motor 2 and increasing its output.

[0117] The dielectric breakdown voltage of the thermoplastic polyimide resin film 10 in silicone oil at 200°C, when measured in accordance with IEC 60243-1, is preferably 4 kV to 70 kV, more preferably 4.5 kV to 65 kV, and even more preferably 5 kV to 60 kV.

[0118] The relative dielectric constant of the thermoplastic polyimide resin film 10 at 23°C, when measured at a frequency of 1 GHz, is preferably 3.5 or less, more preferably 3.3 or less, more preferably 3.2 or less, and even more preferably 3.1 or less. This is because, if the relative dielectric constant of the thermoplastic polyimide resin film 10 exceeds 3.5, the partial discharge inception voltage, which is an initial phenomenon of dielectric breakdown, cannot be sufficiently increased, making it difficult to prevent dielectric breakdown due to surge voltage. The lower limit of the relative dielectric constant at a frequency of 1 GHz is not particularly limited, but the lower the better, and in practical use, it is 1.1 or more.

[0119] More specifically, the relative dielectric constant of the thermoplastic polyimide resin film 10 at 23°C, when measured at a frequency of 1 GHz, is 1.1 or more and 3.5 or less, preferably 2.0 or more and 3.4 or less, more preferably 2.6 or more and 3.3 or less, and even more preferably 2.7 or more and 3.2 or less.

[0120] The dielectric loss tangent of the thermoplastic polyimide resin film 10 at 23°C and a frequency of 1 GHz is 0.01 or less when measured at a frequency of 1 GHz, but is preferably 0.009 or less, more preferably 0.008 or less, and even more preferably 0.005 or less. This is because if the dielectric loss tangent at 1 GHz is 0.01 or less, it is possible to prevent the thermoplastic polyimide resin film 10 from melting or thermally decomposing due to self-heating. The lower limit of this dielectric loss tangent is not limited, but is practically 0.0001 or more.

[0121] The specific dielectric tangent of the thermoplastic polyimide resin film 10 at 23° C., when measured at a frequency of 1 GHz, is 0.0001 to 0.01, preferably 0.002 to 0.009, more preferably 0.003 to 0.008.

[0122] The mechanical properties of the thermoplastic polyimide resin film 10 at 23° C. can be evaluated in terms of maximum strength (maximum tensile strength), elongation at break (tensile elongation at break), and modulus of elasticity (tensile modulus of elasticity). The maximum strength of the thermoplastic polyimide resin film 10 is 50 MPa or more, preferably 50 MPa or more and 200 MPa or less, more preferably 60 MPa or more and 150 MPa or less, and even more preferably 60 MPa or more and 130 MPa or less, when measured in accordance with JIS K7127.

[0123] The elongation at break of the thermoplastic polyimide resin film 10 at 23° C., as measured in accordance with JIS K7127, is preferably 50% or more, more preferably 50% or more and 350% or less, more preferably 55% or more and 340% or less, even more preferably 60% or more and 320% or less, and even more preferably 80% or more and 310% or less. This is because if the maximum strength is less than 50 MPa and the elongation at break is less than 50%, the thermoplastic polyimide resin film 10 does not have sufficient toughness, and therefore, when inserted into the slot 5 of the stator 3 as the wall member 11, problems such as breakage, cracking, and tearing may occur.

[0124] On the other hand, if the maximum strength exceeds 200 MPa and the elongation at break exceeds 350%, the melt viscosity of the molding material M is high, which puts too much strain on the melt extrusion molding machine 20, making it difficult to mold a good resin film by melt extrusion molding.

[0125] The elastic modulus of the thermoplastic polyimide resin film 10 at 23°C, as measured in accordance with JIS K7127, is preferably in the range of 2000 MPa or more and 5000 MPa or less, preferably 2100 MPa or less and 4500 MPa or less, more preferably 2200 MPa or more and 4000 MPa or less, and even more preferably 2500 MPa or more and 3800 MPa or less.

[0126] This is because, if the elastic modulus of the thermoplastic polyimide resin film 10 is less than 2000 MPa, the rigidity is insufficient, and there is a risk of buckling when the thermoplastic polyimide resin film 10 is folded into the wall member 11 and inserted into the slot 5 of the stator 3. Also, if the elastic modulus of the thermoplastic polyimide resin film 10 exceeds 5000 MPa, it takes a long time to mold the thermoplastic polyimide resin film 10, and cost reduction cannot be expected. Also, if the storage modulus is more than 2.5×10 9 If it exceeds Pa, the rigidity of the thermoplastic polyimide resin film 10 will be too high, and bending processability will be reduced.

[0127] The heat resistance of the thermoplastic polyimide resin film 10 can be expressed by a storage modulus at 200° C. From the viewpoint of obtaining excellent heat resistance, the heat resistance of the thermoplastic polyimide resin film 10 is preferably expressed by a storage modulus at 200° C. of 1.0×10 7 Pa or more 2.1×10 9 Pa or less, preferably 1.0×10 8 Pa or more 2.1×10 9 Pa or less, more preferably 5.0×10 8 Pa or more 2.1×10 9 Pa or less, more preferably 1.0×10 9 Pa or more 2.09×10 9 It is better if it is less than Pa.

[0128] This means that the storage modulus at 200°C is 1.0×10 7 If the storage modulus is less than 2.5×10 Pa, sufficient heat resistance cannot be obtained in a high temperature range, and the thermoplastic polyimide resin film 10 will soften and deform when used in a high temperature range of 200° C. 9 If it exceeds this value, the stiffness of the thermoplastic polyimide resin film 10 will be too high, resulting in a decrease in bending processability.

[0129] The water absorption rate of the thermoplastic polyimide resin film 10 at 23°C, when measured in accordance with JIS K7209 Method A, is 1.0% or less, preferably 0.95% or less, and more preferably 0.9% or less. This is because, when the water absorption rate at 23°C is 1.0% or less, high electrical insulation can be maintained even in a high temperature and humidity environment. The lower the water absorption rate of this thermoplastic polyimide resin film 10 at 23°C, the more preferable it is, but in practical use, it is 0% or more.

[0130] According to the above, the maximum strength of the thermoplastic polyimide resin film 10 is set to 50 MPa or more, and the elongation at break of the thermoplastic polyimide resin film 10 is set to 50% or more, so that the thermoplastic polyimide resin film 10 can be given sufficient toughness. Therefore, even if the thermoplastic polyimide resin film 10 is processed and used as an insulating wall member 11, the folded portion after processing does not return to its original state due to springback, and cracks do not occur during processing. In addition, since the elastic modulus of the thermoplastic polyimide resin film 10 is 2000 MPa or more and 5000 MPa or less, the rigidity can be improved, and even if the thermoplastic polyimide resin film 10 is folded into the wall member 11 and inserted into the slot 5 of the stator 3, the risk of buckling can be eliminated.

[0131] In addition, the thermoplastic polyimide resin film 10 has a low water absorption rate of 1.0% or less at 23°C, so that it can maintain high electrical insulation even in a high temperature and humidity environment. This is expected to greatly stabilize the insulation. In addition, the thermoplastic polyimide resin film 10 is thinned to a thickness of 25 μm or more and 500 μm or less, which contributes to increasing the occupancy rate of the conductive winding 6. Furthermore, the thermoplastic polyimide resin film 10 has excellent heat resistance and chemical resistance, so that it can be suitably used for insulating the motor 2 of electric vehicles, hybrid vehicles, plug-in hybrid vehicles, fuel cell vehicles, and the like.

[0132] Next, FIG. 6 shows a second embodiment of the present invention. In this case, an insulating wall member 11 is interposed between each slot 5 of the motor 2 and the multiple conductive windings 6, and is curved into a generally U-shaped cross section to hold the multiple conductive windings 6. Between a pair of opposing pieces of the wall member 11 that hold the multiple conductive windings 6, an insulating partition plate 13 that divides the inside of the wall member 11 into multiple sections and an insulating cover plate 14 that fits over the opening of the wall member 11 are respectively installed. The wall member 11, the partition plate 13 and the cover plate 14 are each made of a thermoplastic polyimide resin film 10 having a thickness of 25 μm or more and 500 μm or less.

[0133] For example, when the motor 2 is a polyphase AC motor, the partition plates 13 are formed into a dish-shaped cross section or the like and attached to the inside of the wall member 11 in the required number, and function as interphase insulating paper to ensure insulation between each phase of the conductive winding 6. The cover plate 14 is formed into a dish-shaped cross section or the like and prevents the conductive winding 6 from protruding from inside the wall member 11 to the outside. The other parts are similar to those of the above embodiment, so description thereof will be omitted.

[0134] In this embodiment, the same effects as those of the above embodiment can be expected, and it is clear that the insulation between each phase of the multi-phase coil can be ensured and the conductive winding 6 can be prevented from protruding from within the wall member 11 while maintaining electrical insulation.

[0135] In the above embodiment, a plurality of slots 5 are recessed in the stator 3 of the rotating electric machine 1, but a plurality of slots 5 may be recessed in the rotor of the rotating electric machine 1, and a thermoplastic polyimide resin film 10 may be inserted into each slot 5 as an insulating material. In the above embodiment, the thermoplastic polyimide resin film 10 is simply shown, but the present invention is not limited thereto. For example, a plurality of thermoplastic polyimide resin films 10 may be laminated and bonded together, or a resin fiber sheet may be laminated and bonded to one or both sides of the thermoplastic polyimide resin film 10. In addition, when it is desired to obtain excellent oil impregnation and slip properties, a pair of upper and lower resin fiber sheets may be provided in a multilayer structure on both the front and back sides of the thermoplastic polyimide resin film 10. In this case, the resin fiber sheet may be a resin film of a crystalline thermoplastic resin having a melting point of 250° C. or higher, or a non-crystalline thermoplastic resin or a thermosetting resin having a glass transition point of 200° C. or higher.

[0136] Specific examples of crystalline thermoplastic resins having a melting point of 250° C. preferably include semi-aromatic polyamide resins such as thermoplastic polyimide (PI) resin, polyamide 4T (PA4T) resin, polyamide 6T (PA6T) resin, modified polyamide 6T (modified PA6T) resin, polyamide 9T (PA9T) resin, and polyamide 10T (PA10T) resin; polyarylene sulfide resins such as polyphenylene sulfide (PPS) resin, polyphenylene sulfide ketone resin, polyphenylene sulfide sulfone resin, and polyphenylene sulfide ketone sulfone resin; and polyether ketone (PEK) resin. Examples of the thermoplastic resin having a glass transition point of 200° C. or higher include polyarylene ether ketone resins such as polyether ether ketone (PEEK) resin, polyether ketone ketone (PEKK) resin, polyether ether ketone ketone (PEEKK) resin, and polyether ketone ether ketone ketone (PEKEKK) resin, polyester resin, fluororesin such as polytetrafluoroethylene (PTFE) resin, polytetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA) resin, and tetrafluoroethylene-hexafluoropropyl copolymer (FEP) resin, and liquid crystal polymer (LCP), etc. Specific examples of the amorphous thermoplastic resin having a glass transition point of 200° C. or higher include polyimide resins such as polyetherimide (PEI) resin, polysulfone resins such as polysulfone (PSU) resin, polyethersulfone (PES) resin, and polyphenylenesulfone (PPSU) resin, and polyarylate (PAR) resin, etc.

[0137] On the other hand, specific examples of thermosetting resins include polyimide resins, polyamideimide (PI) resins and other polyimide resins, epoxy resins, phenolic resins, silicone resins, wholly aromatic polyamide resins, etc. Among these resins, crystalline thermoplastic resins or thermosetting resins are preferred from the viewpoint of chemical resistance. More preferably, thermoplastic polyimide resins are suitable for improving adhesion to the thermoplastic polyimide resin film 10, and even more preferably, polyether ether ketone resins and wholly aromatic polyamide resins (product name: Nomex, DuPont Teijin Advanced Paper Co., Ltd.) are optimal in terms of easy availability and cost. EXAMPLES

[0138] Hereinafter, examples of an insulating material for a rotating electrical machine and a rotating electrical machine according to the present invention will be described together with comparative examples. Example 1 First, a commercially available polyetherimide resin (manufactured by Sabic Corporation, product name: ULTEM9011-1000-NB (hereafter abbreviated as "9011")) was prepared as the amorphous thermoplastic polyimide resin for the molding material, and this polyetherimide resin was placed in a dehumidified hot air dryer heated to 160°C and dried for more than 12 hours. Hereinafter, polyetherimide resin will be abbreviated as PEI resin. 9011 is a condensation polymer of 4,4'-[isopropylidenebis(p-phenyloxy)]diphthalic dianhydride and m-phenylenediamine. The apparent melt viscosity of this 9011 at 370°C was measured and found to be 455 Pa·s.

[0139] The apparent melt viscosity of 9011, an amorphous thermoplastic polyimide resin, was measured using a constant-load extrusion capillary rheometer (Shimadzu Corporation: Product name: Shimadzu Flow Tester CFT-500D). 3 The mixture was packed into a cylinder equipped with a die (diameter: 1 mm, length: 10 mm), and a 1 cm2 pipe was placed on the top of the cylinder. 2 After the cylinder temperature reached 370°C, it was preheated for 5 minutes, and immediately after preheating, a load of 50 kgf was applied to melt and flow out 9011, and its apparent melt viscosity was measured. The method for measuring the apparent melt viscosity of the PEI resin was the same as in the following examples.

[0140] The Tg of 9011 was measured using a differential scanning calorimeter (manufactured by SII Nanotechnologies, product name: High-sensitivity differential scanning calorimeter X-DSC7000) in accordance with JIS K7121 at a temperature rise rate of 10°C / min. The glass transition point of this PEI resin was 210°C. The same method for measuring the Tg of this PEI resin was used in the following examples.

[0141] After drying the PEI resin in this way, it was confirmed that the moisture content of the dried PEI resin was 300 ppm or less, and the PEI resin was set in a single-screw melt extruder equipped with a T-die and melt-kneaded, and the melt-kneaded PEI resin was continuously extruded from the T-die of the single-screw melt extruder and cooled to form a PEI resin film as an insulating material into a strip shape. The moisture content of the PEI resin was confirmed by Karl Fischer titration using a trace moisture measuring device (manufactured by Nitto Seiko Analytech Co., Ltd., product name: CA-310 type). The moisture content of the thermoplastic polyimide resin was measured in the following examples using the same method.

[0142] The cylinder temperature of the single-screw melt extruder was adjusted to 310-370°C, the temperature of the T-die to 370°C, the temperature of the connecting pipe connecting the single-screw melt extruder and the T-die to 375°C, and the temperature of the gear pump and polymer filter to 375°C. When the PEI resin was fed into the single-screw melt extruder, nitrogen gas was supplied at 13 L / min through an inert gas supply pipe. The temperature of the molten molding material was measured from the resin temperature at the inlet of the T-die, and was found to be 375°C.

[0143] Next, the PEI resin film was melt-extruded, and both sides of the 75 μm-thick thermoplastic polyimide resin film made of continuous PEI resin were cut with a slit blade and sequentially wound around a winding tube to produce an insulating material for a rotating electric machine. At this time, the thermoplastic polyimide resin film was sequentially wound around a pair of pressure rolls made of silicone rubber, multiple metal cooling rolls with uneven surfaces and heated to 160° C., and a 6-inch winding tube located downstream of these, and was sandwiched between the pair of pressure rolls and the multiple cooling rolls.

[0144] Once the insulating material for rotating electrical machines was obtained, the film thickness, surface roughness (fine unevenness), slipperiness, electrical insulating properties, mechanical properties, heat resistance, and water absorption of the thermoplastic polyimide resin film were measured, and the results are summarized in Table 1. The surface roughness (fine unevenness) was evaluated using the arithmetic mean roughness (Ra). The slipperiness was evaluated using the slipperiness with a stainless steel plate. The electrical insulating properties were evaluated using the volume resistivity, dielectric breakdown voltage, and dielectric properties. The dielectric breakdown voltage was evaluated in silicone oil at temperatures of 23°C ± 2°C and 200°C. The dielectric properties were evaluated using the relative permittivity and dielectric dissipation factor at a frequency of 1 GHz. The mechanical properties were evaluated using the maximum strength (maximum tensile strength), elongation at break (tensile elongation at break), and modulus of elasticity (tensile modulus of elasticity).

[0145] Insulation film thickness The film thickness of the insulating material was measured using a micrometer (Mitutoyo Corporation, product name: Coolant Proof Micrometer, code: MDC-25PJ) in an environment of 23°C ± 2°C and 50% RH ± 5% RH. Measurements were taken at 10 random locations in the width direction of the insulating material (direction perpendicular to the extrusion direction (hereinafter abbreviated as "TD")), and the average value was taken as the film thickness.

[0146] - Surface roughness of the insulating material (fine unevenness) The surface roughness of the insulating material was evaluated by the arithmetic mean roughness (Ra). Specifically, it was measured at a temperature of 23°C in accordance with JIS B0601-2001. First, the insulating material was left to stand for 24 hours in an environment of a temperature of 23°C ± 2°C and a relative humidity of 50% RH ± 5% RH, and then the extrusion direction (hereinafter abbreviated as "MD") and TD of the insulating material were measured.

[0147] - Slipperiness of insulating material (slipperiness between insulating material and stainless steel plate) The slipperiness of the insulating material at 23°C was evaluated based on the slipperiness between the insulating material and a stainless steel plate. The slipperiness of the insulating material was evaluated based on the static friction coefficient and the dynamic friction coefficient. These static friction coefficient and dynamic friction coefficient were measured in accordance with JIS K7125. Specifically, a surface property measuring device (manufactured by Shinto Scientific, product name: HEDON-14) was used, and the insulating material was left standing for 24 hours in an environment of a temperature of 23°C ± 2°C and a relative humidity of 50% RH ± 5% RH, and after leaving it standing, it was measured under the conditions of a test speed of 100 mm / min, a load of 200 g, and a contact area of ​​63.5 mm x 63.5 mm. Under these conditions, a commercially available stainless steel plate was fixed on the moving table side and the insulating material was fixed on the flat indenter side, and a load of 200 g was applied to measure the static friction coefficient and the dynamic friction coefficient at a speed of 100 mm / min.

[0148] Electrical insulation properties of insulation materials The electrical insulating properties of the insulating material were evaluated by volume resistivity, dielectric breakdown voltage, relative dielectric constant at 1 GHz, and dielectric loss tangent.

[0149] -Volume resistivity of insulating material The volume resistivity of the insulating material was measured at a temperature of 23°C in accordance with JIS C2139-3-1. Specifically, the insulating material was first cut into a size of MD: 100 mm x TD: 100 mm to prepare a test piece, and the test piece was left to stand for 24 hours in an environment of a temperature of 23°C ± 2°C and a relative humidity of 50% RH ± 5% RH. After standing, the test piece was attached to the electrode part of a measuring instrument (manufactured by HIOKI EE Co., Ltd., product name: flat sample electrode SME-8310). After the test piece was attached in this way, an applied voltage of 500 V was applied, and the resistance value after 1 minute was measured using a measuring instrument (manufactured by HIOKI EE Co., Ltd., product name: Super Insulation Meter SM-8220), and the volume resistivity was calculated using the following formula. The volume resistivity was measured five times and the average value was used.

[0150] Volume resistivity (Ω cm)=(19.6 / t)×Rv Where, t: thickness of the test piece (cm) Rv: Measured volume resistance (Ω)

[0151] -Insulation breakdown voltage The dielectric breakdown voltage of the insulating material was measured in silicone oil at temperatures of 23°C and 200°C. The measurements were performed in accordance with IEC 60243-1. Specifically, measurements were performed in silicone oil using the temperature-rising method (short-time method) under conditions of alternating current (50Hz), temperature of 23°C ± 2°C, relative humidity of 50%RH ± 5%RH and temperature of 200°C, with an upper electrode of cylindrical shape with a diameter of 25 mm and a height of 25 mm, and a lower electrode serving as a base of cylindrical shape with a diameter of 25 mm and a height of 25 mm. The dielectric breakdown voltage was measured five times and the average value was used.

[0152] ·Dielectric properties of insulating material [frequency: 1GHz] The dielectric constant and dielectric loss tangent of the insulating material at a frequency of 1 GHz were measured by the cavity resonator perturbation method using a network analyzer [Network Analyzer MS46122B, manufactured by Anritsu Corporation]. The dielectric properties at 1 GHz were measured using a 1 GHz cavity resonator [Model: TMR-1A, manufactured by Keycom Corporation] in accordance with ASTM D2520. The dielectric properties were measured after leaving the material to stand for 24 hours in an environment with a temperature of 23°C ± 2°C and a relative humidity of 50% ± 5% RH, and then again in an environment with a temperature of 23°C ± 2°C and a relative humidity of 50% ± 5% RH. The dielectric constant and dielectric loss tangent were measured five times each, and the average values ​​were used.

[0153] · Mechanical properties of insulation materials The mechanical properties of the insulating material were evaluated in terms of maximum strength, elongation at break, and elastic modulus at a temperature of 23°C. These mechanical properties were measured in both MD and TD. The measurements were performed in accordance with JIS K7127, with a tensile speed of 50 mm / min, at a temperature of 23°C±2°C, and at a relative humidity of 50%RH±5%RH for 24 hours, and then under conditions of a temperature of 23°C±2°C and a relative humidity of 50%RH±5%RH after the measurements were performed. The maximum strength, elongation at break, and elastic modulus were each measured five times and the average values ​​were calculated.

[0154] ·Heat resistance of insulation material The heat resistance of the insulating material was evaluated by the storage modulus (E') of the insulating material at 200°C. The storage modulus of the insulating material was measured in both MD and TD. Specifically, when measuring the storage modulus of the insulating material in MD, a piece was cut to a size of MD60mm x TD6mm, and when measuring the storage modulus in TD, the piece was cut to a size of MD6mm x TD60mm. The storage modulus was measured in tension mode using a viscoelasticity spectrometer (TS Instruments Japan, product name: RSA-G2) under the conditions of a frequency of 1Hz, strain of 0.1%, heating rate of 3°C / min, measurement temperature range of -60°C to 360°C, and chuck distance of 21mm, and the storage modulus at 200°C was obtained.

[0155] -Water absorption of insulation material The water absorption of the insulating material was evaluated by its water absorption rate, which was measured in accordance with JIS K 7209 Method A at an environment of 23°C. Specifically, the insulating material was first cut into test pieces measuring MD 100 mm x TD 100 mm, and the test pieces were dried in an oven adjusted to 50°C for 24 hours.

[0156] After drying the test pieces for 24 hours in this way, they were placed in a desiccator and cooled to 23°C, and then the mass of the test pieces was measured. Subsequently, the test pieces were immersed in distilled water at 23°C ± 2°C for 14 days, and then removed from the distilled water. The surface moisture of the removed test pieces was wiped off with paper, and the mass of the test pieces was immediately measured, and the water absorption rate was calculated using the following formula, and the results are shown in Table 1. The water absorption rate was measured five times and the average value was calculated. Water absorption rate (%)={(m2-m1) / m1}×100 Where, m1: mass of the test piece before immersion (mg) m2: Mass of the test piece after immersion (mg)

[0157] Example 2 A thermoplastic polyimide resin film having a different thickness from that of Example 1 was produced by the same method as Example 1 using the PEI resin used in Example 1 as a commercially available amorphous thermoplastic polyimide resin. Both sides of the thermoplastic polyimide resin film thus obtained were cut with a slit blade and sequentially wound around a winding tube of a winding machine to produce an insulating material for a rotating electric machine. The film thickness, surface roughness (fine unevenness), slipperiness, electrical insulation properties, mechanical properties, heat resistance, and water absorption of the obtained insulating material were evaluated by the same method as Example 1, and the results are summarized in Table 1.

[0158] Example 3 As a commercially available amorphous thermoplastic polyimide resin, the PEI resin (product name: 9011) in Example 1 was changed to ULTEM1010-1000-NB (product name of Sabic Corporation (hereinafter abbreviated as "1010")), and a thermoplastic polyimide resin film with a different thickness from that of Example 1 was produced in the same manner as in Example 1. 1010 is a condensation polymer of 4,4'-[isopropylidenebis(p-phenyloxy)]diphthalic dianhydride and m-phenylenediamine.

[0159] During production, 1010 was placed in a dehumidified hot air dryer heated to 160°C and dried for 12 hours. The apparent melt viscosity of this 1010 at 370°C was measured by the same method as in Example 1, and was found to be 471 Pa·s. In addition, the Tg of 1010 was measured by the same method as in Example 1, and was found to be 211°C. The moisture content of the molding material dried by the same method as in Example 1 was measured, and it was confirmed that the moisture content of the dried 1010 was 300 ppm or less.

[0160] After the confirmation, a thermoplastic polyimide resin film was produced in the same manner as in Example 1, and both sides of the thermoplastic polyimide resin film were cut with a slit blade and sequentially wound around a winding tube of a winder to produce an insulating material for a rotating electric machine. The film thickness, surface roughness (fine unevenness), slipperiness, electrical insulating properties, mechanical properties, heat resistance, and water absorption of the obtained insulating material were evaluated in the same manner as in Example 1, and the results are summarized in Table 1.

[0161] Example 4 First, as a commercially available amorphous thermoplastic polyimide resin, the PEI resin (product name: 9011) in Example 1 was changed to ULTEMCRS5001-1000-NB (product name manufactured by Sabic Corporation; hereinafter abbreviated as "CRS5001"), and a thermoplastic polyimide resin film having a different thickness from that of Example 1 was produced in the same manner as in Example 1. CRS5001 is a polycondensate of 4,4'-[isopropylidenebis(p-phenyleneoxy)diphthalic dianhydride] and p-phenylenediamine.

[0162] At this time, CRS5001 was placed in a dehumidified hot air dryer heated to 160°C and dried for 12 hours. The apparent melt viscosity of this CRS5001 at 370°C was measured by the same method as in Example 1, and the apparent melt viscosity of CRS5001 was 977 Pa·s. Furthermore, the Tg of CRS5001 was measured by the same method as in Example 1, and the Tg of CRS5001 was 222°C. The moisture content of the molding material dried by the same method as in Example 1 was measured, and it was confirmed that the moisture content of the dried CRS5001 was 300 ppm or less.

[0163] After the confirmation, a thermoplastic polyimide resin film was produced in the same manner as in Example 1, and both sides of the thermoplastic polyimide resin film were cut with a slit blade and sequentially wound around a winding tube of a winder to produce an insulating material for a rotating electric machine. The film thickness, surface roughness (fine unevenness), slipperiness, electrical insulating properties, mechanical properties, heat resistance, and water absorption of the obtained insulating material were evaluated in the same manner as in Example 1, and the results are summarized in Table 1.

[0164] Example 5 The PEI resin used in Example 4 was used as a commercially available amorphous thermoplastic polyimide resin, and a thermoplastic polyimide resin film having a thickness different from that of Example 4 was produced in the same manner as in Example 1. Both sides of this thermoplastic polyimide resin film were cut with a slit blade, and the film was sequentially wound around a winding tube of a winding machine to produce an insulating material for a rotating electric machine. The film thickness, surface roughness (fine unevenness), slipperiness, electrical insulation properties, mechanical properties, heat resistance, and water absorption of the obtained insulating material were evaluated in the same manner as in Example 1, and the results are shown in Table 1.

[0165] Example 6 First, a commercially available thermoplastic polyimide resin was changed to a crystalline thermoplastic polyimide resin, and a crystalline thermoplastic polyimide resin consisting of 4,4'-bis(3-aminophenoxy)biphenyl and pyromellitic dianhydride (manufactured by Mitsui Chemicals, Inc., product name: Aurum PL450C, (hereinafter referred to as "PL450C")) was prepared, and this PL450C was placed in a dehumidified hot air dryer heated to 200°C and dried for 12 hours or more. This crystalline thermoplastic polyimide resin consisting of 4,4'-bis(3-aminophenoxy)biphenyl and pyromellitic dianhydride is hereinafter referred to as TPI resin (A).

[0166] The apparent melt viscosity of PL450C at 390°C was measured in the same manner as in Example 1, and was 1110 Pa s. In Example 1, the cylinder temperature of the constant-load extrusion-type capillary rheometer was measured at 370°C, but in Example 6, the cylinder temperature was changed to 390°C, and the apparent melt viscosity was measured, and was found to be 1110 Pa s. The measurements were performed in the same manner as in Example 1, except for the cylinder temperature.

[0167] The apparent melt viscosity of PL450C was measured using a constant load extrusion capillary rheometer (Shimadzu Corporation: Product name: Shimadzu Flow Tester CFT-500D). 3 The mixture was packed into a cylinder equipped with a die (diameter: 1 mm, length: 10 mm), and a 1 cm2 pipe was placed on the top of the cylinder. 2 A plunger was attached, and when the cylinder temperature reached 390°C, it was preheated for 5 minutes. Immediately after preheating, a load of 50 kgf was applied to melt and flow out the PL450C, and its apparent melt viscosity was measured.

[0168] The Tm of PL450C was measured using a differential scanning calorimeter (manufactured by SII NanoTechnology, product name: High-sensitivity differential scanning calorimeter X-DSC7000) in accordance with JIS K7121 at a heating rate of 10°C / min. The Tm of PL450C resin was measured to be 385°C.

[0169] After drying the PL450C, it was confirmed that the moisture content of the dried PL450C was 300 ppm or less. The PL450C was then set in a single-screw melt extruder equipped with a T-die and melt-kneaded. The melt-kneaded PL450C was continuously extruded from the T-die of the single-screw melt extruder and cooled to form a strip of TPI resin (A) film, which is an insulating material.

[0170] The moisture content of PL450C was measured by the same method as in Example 1. When PL450C was fed into the single-screw melt extruder, nitrogen gas was supplied at 8 L / min through an inert gas supply pipe. The cylinder temperature of the single-screw melt extruder was adjusted to 350 to 420°C, the temperature of the T-die to 420°C, the temperature of the connecting pipe connecting the single-screw melt extruder and the T-die to 420°C, and the gear pump to 420°C. The temperature of the molten molding material was measured from the resin temperature at the inlet of the T-die, and was 423°C.

[0171] Next, the PL450C resin film was melt-extruded, and both sides of the continuous PL450C resin film were cut with a slit blade and sequentially wound around a winding tube to produce an insulating material for a rotating electric machine. At this time, the PL450C resin film was sequentially wound around a pair of pressure rolls made of silicone rubber, multiple metal cooling rolls with unevenness on the circumferential surface and heated to 240°C, and a 6-inch winding tube located downstream of these, and was sandwiched between the pair of pressure rolls and the multiple cooling rolls. When the insulating material was obtained, the film thickness, surface roughness (fine unevenness), slipperiness, electrical insulation properties, mechanical properties, heat resistance, and water absorption of the obtained insulating material were evaluated by the same method as in Example 1 and are listed in Table 1.

[0172] [Table 1]

[0173] Example 7 Using the TPI resin (A) used in Example 6 as a commercially available crystalline thermoplastic polyimide resin, a TPI resin (A) film having a different thickness from that of Example 6 was produced by the same method as in Example 6. Both sides of the TPI resin (A) film thus obtained were cut with slits and sequentially wound around a winding tube of a winding machine to produce an insulating material.

[0174] The film thickness, surface roughness (fine unevenness), slipperiness, electrical insulation properties, mechanical properties, heat resistance, and water absorption of the obtained insulating material were evaluated in the same manner as in Example 1, and the results are shown in Table 2.

[0175] Example 8 Using the TPI resin (A) used in Example 6 as a commercially available crystalline thermoplastic polyimide resin, a TPI resin (A) film having a thickness different from that of Examples 6 and 7 was produced in the same manner as in Example 6. Both sides of the TPI resin (A) film thus obtained were cut with slits and sequentially wound around a winding tube of a winding machine to produce an insulating material.

[0176] The film thickness, surface roughness (fine unevenness), slipperiness, electrical insulation properties, mechanical properties, heat resistance, and water absorption of the obtained insulating material were evaluated in the same manner as in Example 1, and the results are shown in Table 2.

[0177] Example 9 A crystalline thermoplastic polyimide resin consisting of an aliphatic diamine and pyromellitic acid (manufactured by Mitsubishi Gas Chemical Co., Ltd., product name: Surprime TO-65, hereinafter referred to as "TO-65") was prepared as a commercially available crystalline thermoplastic polyimide resin, and this crystalline thermoplastic polyimide resin was placed in a dehumidifying dryer heated to 160°C and dried for 12 hours or more. This crystalline thermoplastic polyimide resin consisting of an aliphatic diamine and pyromellitic acid is hereinafter referred to as TPI resin (S). The apparent melt viscosity of this TO-65 at 350°C was measured at 370°C in Example 1, but was changed to 350°C in Example 6. The apparent melt viscosity of TO-65 was 1530 Pa·s.

[0178] The Tm of TO-65 was measured using a differential scanning calorimeter (manufactured by SII NanoTechnology, product name: High-sensitivity differential scanning calorimeter X-DSC7000) in accordance with JIS K7121 at a heating rate of 10°C / min. The melting point of the TPI resin was measured to be 324°C.

[0179] After drying the TO-65, it was confirmed that the moisture content of the dried TO-65 was 300 ppm or less. The TO-65 was then set in a single-screw melt extruder equipped with a T-die and melt-kneaded. The melt-kneaded TO-65 was then continuously extruded from the T-die of the single-screw melt extruder and cooled to form the TO-65 into a strip of insulating material.

[0180] The moisture content of TO-65 was measured in the same manner as in Example 1. When TO-65 was fed into the single-screw melt extruder, nitrogen gas was supplied at 20 L / min through an inert gas supply pipe. The cylinder temperature of the single-screw melt extruder was adjusted to 210 to 360°C, the temperature of the T-die to 360°C, the temperature of the connecting pipe connecting the single-screw melt extruder and the T-die to 365°C, and the gear pump to 365°C. The temperature of the molten molding material was measured from the resin temperature at the inlet of the T-die, and was found to be 363°C.

[0181] Next, TO-65 was melt-extruded, and both sides of the continuous TO-65 resin film were cut with a slit blade and sequentially wound around a winding tube to produce an insulating material for a rotating electric machine. At this time, the TO-65 resin film was sequentially wound around a pair of silicone rubber pressure rolls, multiple metal cooling rolls with uneven surfaces heated to 140°C, and a 6-inch winding tube located downstream of these, and was sandwiched between the pair of pressure rolls and the multiple cooling rolls.

[0182] Once the insulating material was obtained, the film thickness, surface roughness (fine unevenness), slipperiness, electrical insulation properties, mechanical properties, heat resistance, and water absorption properties of the obtained insulating material were evaluated in the same manner as in Example 1, and the results are listed in Table 2.

[0183] Example 10 Using the TPI resin (S) used in Example 9 as a commercially available crystalline thermoplastic polyimide resin, a TO-65 resin film with a different thickness from that of Example 9 was produced by the same method as in Example 9, and both sides of the obtained TO-65 resin film were cut with slits and sequentially wound on a winding tube of a winder to produce an insulating material for a rotating electric machine. The film thickness, surface roughness (fine unevenness), slipperiness, electrical insulation properties, mechanical properties, heat resistance, and water absorption of the obtained insulating material were evaluated by the same method as in Example 1, and the results are summarized in Table 2.

[0184] Comparative Example 1 Instead of a thermoplastic polyimide resin film, a conventional heat-insoluble polyimide resin film was used. Specifically, a commercially available heat-insoluble polyimide resin film [manufactured by Toray DuPont, product name: Kapton 500H (hereinafter referred to as "500H")] was used. Hereinafter, heat-insoluble polyimide resin is abbreviated to PI resin. The film thickness, surface roughness (fine unevenness), slipperiness, electrical insulation properties, mechanical properties, heat resistance, and water absorption properties of Kapton 500H were evaluated by the same method as in Example 1, and are summarized in Table 2.

[0185] [Table 2]

[0186] 〔evaluation〕 In the case of the insulating materials of each embodiment, unlike the comparative examples, the maximum strength of the thermoplastic polyimide resin film is 50 MPa or more, the elongation at break of the thermoplastic polyimide resin film is 50% or more, and the elastic modulus of the thermoplastic polyimide resin film is 2000 MPa or more and 5000 MPa or less, so that the thermoplastic polyimide resin film can be given sufficient toughness. Therefore, even if the thermoplastic polyimide resin film is processed and used as an insulating wall member, it is presumed that the folded part after processing will return to its original state and that cracks during processing can be effectively prevented. In addition, since the rigidity of the thermoplastic polyimide resin film can be improved, it is presumed that even if the thermoplastic polyimide resin film is folded into a wall member and inserted into a slot of a stator, the risk of buckling can be eliminated.

[0187] Furthermore, in the case of the insulating materials of each Example, unlike the Comparative Example, the water absorption rate of the thermoplastic polyimide resin film is 1.0% or less, so it is expected that high electrical insulation can be maintained even in a high temperature and humidity environment, and that stable insulation properties can be expected. [Industrial Applicability]

[0188] The insulating material for a rotating electric machine and the rotating electric machine according to the present invention are used in the manufacturing fields of electricity, electronics, automobiles, railway cars, etc. [Explanation of symbols]

[0189] 1 Rotating Electric Machine 2 Motors 3 Stator 4 cores 5 Slots 6 Conductive Winding 10 Thermoplastic polyimide resin film 11 Wall components 13 Partition plate (construction member) 14 Lid plate (erecting component) 20 Melt extrusion machine 23 Dice 27 Pressure Roll 28 Cooling roll 30 Winder M Molding material

Claims

1. A rotating electric insulating material using a resin film for insulation of a rotating electric machine, the resin film being a thermoplastic polyimide resin film, the thermoplastic polyimide resin film having a maximum strength of 50 MPa or more when measured in accordance with JIS K7127, a breaking elongation of 50% or more when measured in accordance with JIS K7127, a modulus of elasticity of 2000 MPa or more and 5000 MPa or less when measured in accordance with JIS K7127, and a water absorption of 1.0% or less when measured in accordance with JIS K7209 Method A.

2. 2. An insulating material for rotating electrical machines according to claim 1, wherein the thermoplastic polyimide resin film has a dielectric breakdown voltage in silicone oil at 23° C. of 4 kV to 80 kV when measured in accordance with IEC 60243-1.

3. 2. The insulating material for rotating electrical machines according to claim 1, wherein the thermoplastic polyimide resin film has a dielectric breakdown voltage in silicone oil at 200° C. of 4 kV to 70 kV when measured in accordance with IEC 60243-1.

4. 3. An insulating material for a rotating electric machine according to claim 1 or 2, wherein the thermoplastic polyimide resin film has a relative dielectric constant of 3.5 or less at 23°C when measured at a frequency of 1 GHz, and a dielectric dissipation factor of 0.003 or more and 0.008 or less at 23°C when measured at a frequency of 1 GHz.

5. When the storage modulus of the thermoplastic polyimide resin film at 200°C was measured, it was 1.0 x 10 ７ Pa or more 2.1×10 ９ 3. The insulating material for a rotating electrical machine according to claim 1, wherein the hardness is set to 0.1 Pa or less.

6. 3. A rotating electric machine comprising a stator surrounding a rotor, the stator comprising a core fitted to the rotor, slots recessed into a surface of the core facing the rotor, and conductive windings housed in the slots, an insulating wall member being interposed between the slots and the conductive windings, the wall member being made of the insulating material for rotating electric machines according to claim 1 or 2.

7. 3. A rotating electric machine comprising: a stator surrounding a rotor, the stator comprising a core fitted to the rotor, a slot formed as a recess in a surface of the core facing the rotor, and a conductive winding housed in the slot, an insulating wall member is interposed between the slot and the conductive winding and bent into a generally U-shaped cross section to sandwich the conductive winding, an insulating installation member is installed between a plurality of opposing pieces of the wall member that face each other with the conductive winding in between, and the wall member and the installation member are each made of the insulating material for a rotating electric machine according to claim 1 or 2.

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