Electrical insulation film for motor

Abstract

To provide an electrical insulation film for motor that does not break during motor assembly and has a superior heat resistance, even when the film is made thinner.SOLUTION: An electrical insulation film for motor contains polyaryletherketone and polyetherimide and has at least two glass transition temperatures between 150 and 250°C.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an insulating film that is particularly suitable for use in motors, and in particular, to an insulating film that can be suitably used as wedge paper or slot paper. [Background technology]

[0002] In motors that provide the driving force for home appliances, industrial equipment, etc., slot paper is interposed as an insulating film between the core and the winding coil in the slot in the stator core. Usually, the slot paper is inserted into the slot from the opening on the end face of the stator core, the winding coil is wound in the slot of the iron core, and the slot paper for insulation is interposed between the winding coil and the slot.

[0003] Currently, the most commonly used motor insulating film of this type (also called "motor insulating paper") is a composite insulating material in which aramid paper is bonded to both sides of a resin film such as polyethylene naphthalate film with an adhesive. Insulating films made of engineering plastics, such as polyetherimide, have also been developed, as they have excellent chemical resistance, heat resistance, and mechanical properties.

[0004] For example, Patent Document 1 discloses a laminated film of polyether ether ketone resin and polyetherimide, and describes that the film can be suitably used as a slot paper (slot liner) for motors.

[0005] Patent Document 2 discloses a blend of polyether ether ketone resin, polyetherimide, and an inorganic filler, and describes that this blend can achieve both heat resistance and flexibility.

[0006] Patent Document 3 discloses an insulating film including a polyether ether ketone layer having a relative crystallinity of 90% or more and a polyetherimide layer, the polyether ether ketone layer being provided on both outermost layers.

[0007] Patent Document 4 discloses an insulating film including an engineering plastic, such as polyether ether ketone or polyether imide, that has heat resistance at 100°C or higher and chemical resistance to refrigerants such as oil, and that has an arithmetic mean roughness (Ra) of 0.15 μm or more and 1.50 μm or less on at least one side. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Japanese Patent Application Publication No. 62-148260 [Patent Document 2] Japanese Patent Publication No. 149436 / 1983 [Patent Document 3] JP 2020-21626 A [Patent Document 4] JP 2020-150582 A Summary of the Invention [Problem to be solved by the invention]

[0009] In recent years, with the improvement of motor performance, there is a demand for small, highly efficient motor parts. Therefore, there is a demand for thinner motor insulation films to increase the space factor of the winding coil. In addition, because miniaturization makes it easier for heat to build up inside the motor, there is also a demand for further heat resistance. However, if the insulating film is made thinner, there is a possibility that it may be torn by bending during motor assembly, resulting in a loss of insulating properties.

[0010] SUMMARY OF THE PRESENT EMBODIMENTS The present invention provides a motor insulating film which, even when made thin, will not break during motor assembly and has excellent heat resistance. [Means for solving the problem]

[0011] In order to solve the above problems, the motor insulating film proposed by the present invention has the following configuration.

[0012] [1] A first aspect of the present invention is a film for insulating motors, comprising polyaryletherketone and polyetherimide, and having at least two glass transition temperatures between 150 and 250°C.

[0013] [2] The second aspect of the present invention is the first aspect, wherein the storage modulus (E') at 230°C is 1.0 x 10 8 ~2.0×10 9 This is a motor insulation film with a resistance of 100%.

[0014] [3] A third aspect of the present invention is the composition according to the first or second aspect, wherein the storage modulus (E') at 190 to 230°C is 1.0 × 10 8 ~2.0×10 9 This is a motor insulation film with a resistance of 100%.

[0015] [4] A fourth aspect of the present invention is the motor insulating film according to any one of the first to third aspects, wherein the polyaryletherketone is polyetheretherketone.

[0016] [5] A fifth aspect of the present invention is the motor insulating film according to any one of the first to fourth aspects, wherein the polyetherimide is a polyetherimide having a repeating unit represented by the following formula (1):

[0017] TIFF2025005047000002.tif43166

[0018] [6] A sixth aspect of the present invention is the motor insulating film according to any one of the first to fifth aspects, which has a thickness of 10 μm or more and 200 μm or less.

[0019] [7] A seventh aspect of the present invention is the motor insulating film according to any one of the first to sixth aspects, which has a bending endurance of 100 or more times in the MIT folding endurance test (JIS P8115:2001).

[0020] [8] An eighth aspect of the present invention is the motor insulating film according to any one of the first to seventh aspects, wherein the dynamic friction coefficient between at least one surface of the film and the stainless steel plate is 0.3 or less.

[0021] [9] A ninth aspect of the present invention is a motor insulating film according to any one of the first to eighth aspects, which is a slotted paper.

[0022]

[10] A tenth aspect of the present invention is a motor provided with the motor insulating film according to any one of the first to ninth aspects. Effect of the Invention

[0023] The motor insulating film proposed by the present invention not only has excellent heat resistance, but also prevents breakage during motor assembly even when the film is made thin, for example, less than 200 μm. [Brief description of the drawings]

[0024] [Figure 1] FIG. 2 is a graph showing the relationship between the temperature and the loss tangent (tan δ) of the films used in the examples and comparative examples. [Diagram 2] FIG. 13 is a diagram showing an assembly jig used in a motor assembly test in the examples. [Diagram 3] FIG. 11 is a top view of an assembly jig and a copper wire bundle during a motor assembly test in an embodiment. [Figure 4] FIG. 13 is a diagram showing a rectangular film sample for creating a slotted paper-shaped test piece during a motor assembly test in the examples. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0025] An example of an embodiment of the present invention will be described below, however, the present invention is not limited to the embodiment described below.

[0026] <Film of the present invention> A film according to an embodiment of the present invention (hereinafter referred to as the "film of the present invention") is a film containing polyaryletherketone and polyetherimide.

[0027] [Polyaryletherketone] Polyaryletherketones are homopolymers or copolymers that contain monomer units containing one or more aryl groups, one or more ether groups and one or more ketone groups. Specific examples of polyaryletherketones include polyetheretherketone (PEEK, glass transition temperature (hereinafter referred to as "Tg"): 143°C, crystalline melting peak temperature (hereinafter referred to as "Tm"): 334°C), polyetherketoneketone (PEKK), polyetherketone (PEK, Tg: 157°C, Tm: 373°C), polyetherketoneetherketoneketone (PEKEKK), polyetheretherketoneketone (PEEKK, Tg: 153°C, Tm: 370°C), polyetherdiphenyletherketone (PEDEK), and copolymers thereof (for example, PEEK-PEDEK copolymer). Polyaryletherketones can be used alone or in combination of two or more types. The polyaryl ether ketone may contain a biphenyl structure, a sulfonyl group, or other repeating units, so long as the effects of the present invention are not adversely affected.

[0028] From the viewpoints of mechanical strength and ease of melt-kneading and molding, the mass average molecular weight (Mn) of the polyaryl ether ketone is preferably 7,000 to 30,000, more preferably 10,000 or more or 25,000 or less, and even more preferably 12,000 or more or 20,000 or less. The mass average molecular weight of the polyaryl ether ketone is a value obtained by measurement using GPC (Gel Permeation Chromatography).

[0029] From the viewpoint of thermal stability, the polyaryl ether ketone preferably has a mass loss rate of 10% or less when the product temperature is maintained at 400°C for 60 minutes, more preferably 5% or less, and even more preferably 3% or less. On the other hand, the lower limit of the mass reduction rate is not particularly set, but is usually 0.1% or more. The above product temperature means the temperature of a film made only from polyaryl ether ketone.

[0030] [Polyether ether ketone] Among the polyaryletherketones, polyetheretherketone (PEEK) is particularly preferred because of its excellent heat resistance, mechanical properties, chemical resistance, and the like.

[0031] Polyetheretherketone has a repeating unit (a-1) having two ether groups and one ketone group.

[0032] The total number (degree of polymerization) of the repeating units (a-1) of the polyether ether ketone is preferably at least 10, and more preferably at least 20. On the other hand, it is preferably at most 500, and more preferably at most 100. When the total number (degree of polymerization) of the repeating units (a-1) of the polyether ether ketone resin is within this range, the film of the present invention has excellent chemical resistance, heat resistance, and impact resistance, and also has excellent melt moldability since the viscosity when melted is not too high.

[0033] The heat of crystalline fusion of polyether ether ketone is preferably 20 J / g or more, more preferably 25 J / g or more, and even more preferably 30 J / g or more. On the other hand, it is preferably 60 J / g or less, more preferably 55 J / g or less, and even more preferably 50 J / g or less. If the heat of crystalline fusion of polyether ether ketone is within this range, the film of the present invention is excellent in heat resistance, and the thermal energy applied during melt molding is small, so that the film is also excellent in melt moldability.

[0034] The crystalline melting temperature (Tm) of polyether ether ketone is preferably 300° C. or higher, more preferably 320° C. or higher, and even more preferably 330° C. or higher. On the other hand, it is preferably 400° C. or lower, more preferably 380° C. or lower, and even more preferably 360° C. or lower. When the crystalline melting temperature of polyether ether ketone is within this range, the film of the present invention is more excellent in heat resistance, and the viscosity during melting is not too high, so that the film is also excellent in melt moldability. In the present invention, the crystalline melting temperature can be determined from the peak top temperature of the melting peak of the DSC curve detected when the temperature is increased to a temperature range of 30 to 380°C at a rate of 10°C / min using a differential scanning calorimeter (e.g., Pyris1 DSC manufactured by PerkinElmer) in accordance with JIS K7121:2012, the temperature is then decreased to 23°C at a rate of 10°C / min, and the temperature is then increased again to 380°C at a rate of 10°C / min.

[0035] The glass transition temperature (Tg) of polyether ether ketone is preferably 120° C. or higher, and more preferably 140° C. or higher, while it is preferably 200° C. or lower, and more preferably 180° C. or lower. When the glass transition temperature of polyether ether ketone is within this range, the film of the present invention is more excellent in heat resistance, and the viscosity at the time of melting is not too high, so that the film is also excellent in melt moldability.

[0036] The glass transition temperature in the present invention can be determined from the peak of loss tangent (tan δ) obtained by measuring the temperature dispersion of dynamic viscoelasticity described in JIS K7244-4:1999 (for example, a viscoelasticity spectrometer DVA-200 (manufactured by IT Measurement & Control Co., Ltd.)) at a strain of 0.1%, a frequency of 10 Hz, and a temperature range of -50 to 400°C at a heating rate of 3°C / min.

[0037] The polyether ether ketone can be produced by a known method, and a commercially available product can also be used. Examples of commercially available polyether ether ketone products include the "VICTREX PEEK" series manufactured by Victrex, the "KetaSpire" series manufactured by Solvay, and the "VESTAKEEP" series manufactured by Daicel-Evonik.

[0038] [Polyetherimide] Many polyetherimides are highly compatible with the polyaryletherketones, particularly polyetheretherketones, and are easily mixed at the molecular level. Therefore, a resin composition containing both of them is completely compatible and has a single glass transition temperature. However, the polyetherimide used in the film of the present invention is preferably one that is incompatible or partially compatible with polyaryletherketone, particularly polyetheretherketone. The incompatibility or partial compatibility of the two can be confirmed, for example, by the fact that a resin composition containing both or the film of the present invention has at least two glass transition temperatures derived from polyetherimide and polyaryletherketone, respectively.

[0039] From this viewpoint, the polyetherimide used in the film of the present invention is preferably one having a repeating unit (b-1) represented by the following formula (1), that is, a polyetherimide in which the bonding position of the substituent on the aromatic ring is the para position. For example, when a polyetherimide in which the bonding position of the substituent in the aromatic ring is meta-position is added to a polyaryletherketone, the two are completely compatible. On the other hand, when a polyetherimide having a repeating unit (b-1) represented by the following formula (1) is added to a polyaryletherketone, the two are incompatible or partially compatible, and the properties of the polyaryletherketone can be more fully retained, preventing breakage during motor assembly.

[0040] TIFF2025005047000003.tif43166

[0041] The total number (degree of polymerization) of the polyetherimide repeating units (b-1) is preferably 10 or more, more preferably 20 or more, while it is preferably 1000 or less, more preferably 500 or less. When the total number (degree of polymerization) of the polyetherimide repeating units (b-1) is within this range, the film of the present invention is more excellent in heat resistance, and since the viscosity at the time of melting is not too high, it is also excellent in melt moldability.

[0042] The glass transition temperature (Tg) of the polyetherimide is preferably 200° C. or higher, more preferably 210° C. or higher, and even more preferably 220° C. or higher, while it is preferably 260° C. or lower, more preferably 250° C. or lower, and even more preferably 240° C. or lower. If the glass transition temperature of the polyetherimide is within this range, the film of the present invention will have even better heat resistance, and since the viscosity at the time of melting is not too high, it will also have excellent melt moldability.

[0043] From the viewpoint of increasing folding endurance, the number average molecular weight of the polyetherimide is preferably 5000 or more, more preferably 10000 or more, and even more preferably 15000 or more. On the other hand, from the viewpoint of film formability, the number average molecular weight is preferably 50000 or less, more preferably 40000 or less, and even more preferably 30000 or less. It is preferable that the number average molecular weight of the polyetherimide is within this range, since this will result in excellent folding strength and film formability. The number average molecular weight of polyetherimide is a value obtained by measurement using GPC (Gel Permeation Chromatography).

[0044] From the viewpoint of thermal stability, the polyetherimide preferably has a mass loss rate of 10% or less when the product temperature is maintained at 400°C for 60 minutes, more preferably 5% or less, and even more preferably 3% or less. On the other hand, the lower limit of the mass reduction rate is not particularly set, but is usually 0.1% or more. The above product temperature means the temperature of a film made only from polyetherimide.

[0045] (Content ratio) In the film of the present invention, the total content of polyaryl ether ketone and polyetherimide is preferably 90 parts by mass or more, more preferably 95 parts by mass or more, and even more preferably 99 parts by mass or more, per 100 parts by mass of the film of the present invention, from the viewpoints of heat resistance and bending resistance.

[0046] The content ratio of polyetherimide and polyaryletherketone in the film of the present invention is preferably 5 to 200 parts by mass of polyaryletherketone per 100 parts by mass of polyetherimide. When the content of polyaryl ether ketone is 10 parts by mass or more relative to 100 parts by mass of polyetherimide, the bending resistance is further excellent, and when the content is 175 parts by mass or less, the heat resistance is further excellent. From this viewpoint, the amount of polyaryl ether ketone is preferably 5 to 200 parts by mass per 100 parts by mass of polyetherimide, and more preferably 8 parts by mass or more or 175 parts by mass or less, more preferably 10 parts by mass or more or 165 parts by mass or less, more preferably 12 parts by mass or more or 160 parts by mass or less, and even more preferably 15 parts by mass or more or 155 parts by mass or less.

[0047] [Other ingredients] The film of the present invention may contain "other components" other than the polyaryletherketone and polyetherimide, if necessary. Examples of other components include general resin additives such as heat stabilizers, light stabilizers, antibacterial and antifungal agents, antioxidants, antistatic agents, lubricants, release agents, pigments, dyes, UV absorbers, flame retardants, lubricants, fillers, and reinforcing agents, etc. One or more of these may be contained.

[0048] The film of the present invention may contain an inorganic filler, if necessary. Known inorganic fillers can be used. For example, powdery fillers such as clay, glass, alumina, spherical alumina, silicon dioxide powder (silica, spherical silica, natural or synthetic quartz powder, etc.), aluminum nitride, silicon nitride, graphite, etc.; fibrous fillers such as glass fiber and carbon fiber; inorganic scale-like (plate-like) fillers such as synthetic mica, natural mica (muscovite, phlogopite, sericite, szolite, etc.), calcined natural or synthetic mica, boehmite, talc, illite, kaolinite, montmorillonite, vermiculite, smectite, and plate-like alumina can be mentioned. Among these, plate-like fillers are preferable from the viewpoint of reducing the linear expansion coefficient in the plane direction of the obtained heat-resistant resin plate and suppressing warping and deformation. However, since the inclusion of a filler may cause the composition to become brittle, it is not necessarily required to include the filler.

[0049] The film of the present invention preferably does not contain any resin components other than polyaryletherketone and polyetherimide, for example, does not contain any fluororesin. It is also preferable that the composition does not contain a compatibilizer that makes the polyaryletherketone and the polyetherimide compatible.

[0050] (Thickness) From the viewpoint of bending resistance, the thickness of the film of the present invention is preferably 10 μm or more, more preferably 30 μm or more, even more preferably 50 μm or more, even more preferably 70 μm or more, while from the viewpoint of increasing the space factor of the coil, the thickness is preferably 200 μm or less, more preferably 180 μm or less, even more preferably 160 μm or less, even more preferably 140 μm or less.

[0051] <Physical Properties of the Film of the Present Invention> The film of the present invention may have the following physical properties:

[0052] (glass transition temperature) The film of the present invention preferably has at least two glass transition temperatures between 150 and 250°C. The polyaryletherketone and polyetherimide are incompatible or partially compatible with each other, and the film of the present invention has at least two glass transition temperatures between 150 and 250°C, particularly between 150 and 200°C, so that a decrease in storage modulus (E') at 150 to 250°C, particularly between 150 and 200°C, can be suppressed, and mechanical strength, etc. at such temperatures can be maintained.

[0053] Further, the film of the present invention preferably has glass transition temperatures in the temperature ranges of 150 to 180°C and 220 to 250°C. The glass transition temperature in the former temperature range is more preferably in the range of 155 to 175°C, and more preferably in the range of 160 to 170°C. The glass transition temperature in the latter temperature range is more preferably in the range of 225 to 245°C, and more preferably in the range of 230 to 240°C.

[0054] The glass transition temperature of the film of the present invention can be measured by the measurement method described in the Examples.

[0055] (Storage modulus) The film of the present invention has a storage modulus (E') at 230°C of 1.0 x 108 ~2.0×10 9 Pa is preferred. From the viewpoint of heat resistance, the film of the present invention has a storage modulus (E') at 230°C of 1.0 x 10 8 Pa or more, and more preferably 1.5×10 8 Pa or more, especially 2.0×10 8 It is more preferable that the pressure is 100 Pa or more. There is no particular upper limit for the storage modulus (E') at 230°C, but it is usually 7.0 x 10 9 It is Pa. In order to set the storage modulus (E') at 230°C of the film of the present invention within the above range, for example, when the polyaryletherketone and the polyetherimide are incompatible or partially compatible with each other, it is preferable to adjust the blending ratio of the two, but the method is not limited to this.

[0056] The film of the present invention always has a storage modulus (E') of 1.0 x 10 8 ~2.0×10 9 Pa is preferred. That is, from the viewpoint of heat resistance, the film of the present invention has a storage modulus (E') of always 1.0 × 10 8 Pa or more, and more preferably 1.5×10 8 Pa or more, especially 2.0×10 8 It is more preferable that the pressure is 100 Pa or more. There is no particular upper limit for the storage modulus (E') in the temperature range of 190 to 230 °C, but the upper limit in the temperature range of 190 to 230 °C is 7.0 × 10 9 It is Pa. In order to set the storage modulus (E') of the film of the present invention in the temperature range of 190 to 230°C within the above range, for example, when the polyaryletherketone and the polyetherimide are incompatible or partially compatible with each other, it is preferable to adjust the blending ratio of the two, but the method is not limited to this.

[0057] (Kinematic friction coefficient) The film of the present invention can have a dynamic friction coefficient between at least one surface of the film of the present invention and a SUS plate, measured in accordance with JIS K7125:1999, of 0.3 or less. When the dynamic friction coefficient of the film of the present invention with respect to a SUS plate is 0.3 or less, the film has excellent insertability into a motor core, and furthermore, buckling or breakage when inserted into a slot can be prevented. From this viewpoint, the dynamic friction coefficient of the film of the present invention is preferably 0.3 or less, more preferably 0.29 or less, and even more preferably 0.27 or less. On the other hand, although there is no particular lower limit, it is preferably 0.01 or more, and more preferably 0.05 or more.

[0058] (MIT bending resistance) The film of the present invention can be bent 100 times or more in the MIT folding endurance test (JIS P8115:2001), particularly 100 times or more in both MD (longitudinal direction) and TD (transverse direction). It is preferable that the film of the present invention can be bent 100 times or more in the MIT folding endurance test (JIS P8115:2001) since it has excellent bending resistance and can suppress breakage of the film during assembly of a motor. From this viewpoint, the number of times of bending of the film of the present invention is preferably 100 or more, more preferably 130 or more, and even more preferably 150 or more. In particular, the number of times of bending in both MD (longitudinal direction) and TD (transverse direction) is preferably 100 or more, more preferably 130 or more, and even more preferably 150 or more.

[0059] (mass reduction rate) The film of the present invention preferably has a mass loss rate of 5% or less when the product temperature is kept at 400° C. for 1 hour. When producing the film of the present invention, as described below, it is necessary to knead the polyaryletherketone and the polyetherimide because they need to be melted at a high temperature of, for example, 280° C. or more and 450° C. or less. Therefore, by having a mass loss rate of 5% or less at 400° C., concerns about production troubles and deterioration of film properties during melt processing of the film of the present invention can be further reduced. The mass loss rate of the film of the present invention when the product temperature is maintained at 400°C for 1 hour is more preferably 4% or less, even more preferably 3% or less, even more preferably 2% or less, even more preferably 1% or less, and particularly preferably 0.5% or less.

[0060] <Manufacturing method> The film of the present invention can be formed by a general forming method, for example, extrusion forming, calendar forming, casting forming such as solution casting, inflation forming, etc. Among them, the extrusion forming method, particularly the T-die method, is preferred.

[0061] The film of the present invention may be either a non-oriented film or a oriented film. An unstretched film refers to a film that is not actively stretched for the purpose of controlling the orientation of the film, and includes films that are oriented when the molten resin is drawn down or taken up by a cast roll during extrusion molding such as the T-die method, and films that are stretched less than 2 times by a stretching roll.

[0062] The film of the present invention can be produced by melting, preferably melt-kneading, a composition containing polyaryletherketone and polyetherimide (referred to as "the present resin composition"), followed by extrusion molding and cooling. The extruder may be, for example, a single screw extruder or a twin screw extruder, and functions to melt-knead the present resin composition that is introduced into the extruder. In the present invention, since it is preferable that the polyaryletherketone and the polyetherimide are incompatible or partially compatible with each other, it is preferable to use a single screw extruder.

[0063] The melting temperature is preferably adjusted appropriately depending on the type and mixing ratio of the resin, the presence or absence and type of additives, etc. From the viewpoint of productivity, etc., it is preferably 320°C or higher, more preferably 340°C or higher, even more preferably 350°C or higher, and particularly preferably 360°C or higher. By setting the melting temperature at or above the above temperature, the crystals of the raw material such as pellets are sufficiently melted and are unlikely to remain in the film, so that durability such as the number of folding times and puncture impact strength is likely to be improved. On the other hand, the melting temperature is preferably 450° C. or less, more preferably 430° C. or less, even more preferably 410° C. or less, and particularly preferably 390° C. or less. By setting the melting temperature at or below the above temperature, the resin is unlikely to decompose during melt molding and the molecular weight is likely to be maintained, so that the heat resistance and tensile modulus of the film tend to be improved.

[0064] Thereafter, the melt-kneaded resin composition may be extruded through a T-die to form a film. The T-die functions to continuously extrude a strip of film downward. The temperature during extrusion through this T-die is usually in the range of from the melting point of the resin to the thermal decomposition temperature, and specifically, is preferably 280°C or higher, more preferably 300°C or higher, even more preferably 320°C or higher, particularly preferably 340°C or higher, and most preferably 350°C or higher. On the other hand, the temperature during extrusion through the T-die is preferably 450°C or lower, more preferably 430°C or lower, further preferably 410°C or lower, and particularly preferably 390°C or lower.

[0065] The present resin composition extruded as a film through the T-die may be cooled by contacting it with a cooling machine such as a pressure roll or a cast roll. The pressure roll is rotatably supported below the T-die and holds the cast roll in sliding contact therewith. The cast roll is, for example, a metal roll having a larger diameter than the pressure roll, and is rotatably supported below the T-die to hold the extruded film between the pressure roll and the cast roll, and functions to control the thickness of the film within a predetermined range while cooling the film together with the pressure roll.

[0066] The cooling temperature (for example, the temperature of the cast roll) may be appropriately selected so as to obtain the desired relative crystallinity, but is preferably 30 to 150°C higher than the glass transition temperature of the resin, more preferably 35 to 140°C higher, and particularly preferably 40 to 135°C higher. By setting the cooling temperature within the above range, the cooling rate of the film can be slowed down, and the relative crystallinity tends to be increased. For example, when the resin component contains polyether ether ketone, the cooling temperature is preferably 180°C or higher, more preferably 190°C or higher, even more preferably 200°C or higher, and particularly preferably 210°C or higher. On the other hand, the cooling temperature is preferably 300°C or lower, more preferably 280°C or lower, even more preferably 260°C or lower, particularly preferably 250°C or lower, and most preferably 240°C or lower.

[0067] In general, the crystallization rate of polymer materials is thought to be maximized in the temperature range between the glass transition temperature and the crystal melting temperature, based on the balance between the nucleation rate and growth rate of crystals. When producing a film with a high relative crystallinity, if the cooling temperature (temperature of the cast roll, etc.) is within the range between the lower and upper limits, the crystallization rate will be maximized, making it easier to obtain a crystallized film with excellent productivity.

[0068] When the resin used is a mixture of multiple types of crystalline resins and has multiple glass transition temperatures, the highest temperature is regarded as the glass transition temperature of the resin, and the cooling temperature is adjusted accordingly.

[0069] In order to adjust the relative crystallinity, a heating roll for reheating the film, an oven such as a floating dryer, an infrared heater, or the like may be provided downstream of the casting roll.

[0070] When the film is a stretched film, a stretching device such as a uniaxial stretching device, a sequential biaxial stretching device, or a simultaneous biaxial stretching device is usually provided downstream of the cast roll.

[0071] <Use and mode of use> The film of the present invention can be suitably used for motors in various devices, such as home appliances, audio devices, IT devices, communication devices, office automation devices, medical devices, health care devices, business devices, industrial devices, and transport devices such as automobiles, trains, ships, etc. In particular, it can be suitably used as wedge paper or slot paper for motors.

[0072] <Explanation of terms, etc.> In the present invention, the term "film" includes the term "sheet", and the term "sheet" includes the term "film".

[0073] In the present invention, when it is written "α to β" (α and β are arbitrary numbers), unless otherwise specified, it includes the meaning of "α or more and β or less", as well as "preferably larger than α" or "preferably smaller than β". In addition, when it is stated that "α or more" or "α≦" (α is any number), it also means "preferably greater than α" unless otherwise specified, and when it is stated that "β or less" or "≦β" (β is any number), it also means "preferably smaller than β" unless otherwise specified. EXAMPLES

[0074] An example of the present invention will be described below, however, the present invention is not limited to the example described below.

[0075] [Raw materials] The following raw materials were used in the examples and comparative examples.

[0076] PEI-1: polyetherimide (PEI, having repeating unit (b-1) of formula (1), repeating number of repeating unit (b-1): 28, para-position substitution structure, Tg: 225°C, number average molecular weight (Mn): 16400, 400°C x 60min mass loss rate: 1.0%, amorphous resin)

[0077] PEI-2: Polyetherimide (PEI, does not have the repeating unit (b-1) of formula (1), repeating unit number: 42, meta-position substitution structure, Tg: 215°C, number average molecular weight (Mn): 25,000, 400°C x 60 min mass loss rate: 1.9%, amorphous resin)

[0078] PEEK: polyether ether ketone (PEEK, having repeating unit (a-1), repeating number of repeating unit (a-1): 59, mass average molecular weight: 17000, Tg: 150°C, Tm: 340°C, heat of crystalline fusion: 41 J / g, crystallization temperature: 295°C, mass reduction rate at 400°C for 60 min: 0.7%)

[0079] [Examples 1 to 3 and Comparative Examples 1 to 4] The raw materials were dry-blended to obtain the ratios shown in Table 1, and then melt-kneaded at 380°C using a Φ40 mm single-screw extruder. The raw materials were continuously extruded from a T-die at 380°C, and then cooled with a casting roll at 160°C to produce a film (sample) having a thickness of 125 μm.

[0080] <Evaluation and Measurement> The films produced in the above Examples and Comparative Examples were evaluated and measured for various items as follows. Here, the "longitudinal" or "machine direction" (MD) of the film refers to the direction in which the film-shaped molded product is extruded from the T-die, and the direction perpendicular to this in the film plane is the "transverse" or "short direction" (TD).

[0081] (glass transition temperature) In accordance with JIS K7244-4:1999, the glass transition temperature (Tg) was determined from the peak of the loss tangent (tan δ) detected when measurements were taken at a strain of 0.1%, a frequency of 10 Hz, and a temperature range of -50 to 400°C at a heating rate of 3°C / min using a viscoelasticity spectrometer DVA-200 (manufactured by IT Measurement & Control Co., Ltd.).

[0082] (Storage modulus) The storage modulus in the transverse direction (TD) of the films produced in the Examples and Comparative Examples was measured at 4 mm in the extrusion direction × 20 mm between the benchmark lines in the transverse direction. The storage modulus was measured using the above-mentioned sample in accordance with JIS K7244-4:1999 using a viscoelasticity spectrometer "DVA-200 (manufactured by IT Measurement & Control Co., Ltd.)" at a frequency of 10 Hz, a strain of 0.1%, and a temperature increase rate of 3°C / min from -50 to 400°C to measure the tensile storage modulus.

[0083] (Kinematic friction coefficient with SUS plate) For each film produced in the Examples and Comparative Examples, measurements were carried out in the machine direction (MD) using a plastic film sliding tester (INTESCO) in accordance with JIS K7125:1999 to measure the dynamic friction coefficient with a SUS plate (stainless steel plate).

[0084] (Folding endurance test) For each of the films produced in the Examples and Comparative Examples, the number of folding cycles was measured in the MD (longitudinal direction) and TD (transverse direction) of the film using an MIT folding fatigue tester (manufactured by Toyo Seiki Co., Ltd.) in accordance with JIS P8115:2001.

[0085] (Motor assembly test) Each film produced in the Examples and Comparative Examples was cut into a rectangular shape measuring 114 mm in length and 40 mm in width, and folded at right angles to the horizontal direction at two points 3.5 mm above and below in the vertical direction (FIG. 4(i)(ii)), and then folded at right angles to the vertical direction at two points 17.5 mm above and below in the horizontal direction (FIG. 4(iii)(iv)), to obtain a slotted paper-shaped test piece. Next, an assembly jig (see Figure 2) was prepared with eight holes of 20 mm length and 4.8 mm width at 10 mm intervals in a steel material (SS400) of 33 mm length, 140 mm width, and 100 mm height, and the test piece was inserted into each hole. At that time, both the folds (i) and (ii) in Figure 4 were made to be outside the holes. Then, 100 copper wires of 0.9 mm diameter cut to a length of about 700 mm were prepared, and as shown in Figure 3, two sets of copper wire bundles consisting of 25 copper wires were inserted into the slot paper of each hole of the assembly jig so that they faced in opposite directions. After inserting the copper wires, the copper wire bundles protruding to a height of about 6 mm to 12 mm on the top and bottom of the assembly jig were hit with a hammer and compressed until the height of the copper wire bundle became 3 mm to 7 mm. After compression, the copper wire bundles and the test piece were removed from the assembly jig, and the test piece was visually observed. If the test piece was not torn, it was rated as "○ (pass)", and if the test piece was torn, it was rated as "× (fail)".

[0086] (mass reduction rate) Using 5 mg of each film sample, the sample temperature was raised from 35°C to 400°C at a heating rate of 50°C / min in an air atmosphere using a thermogravimetric analyzer (STA2000RV (Hitachi High-Technologies Corporation) and the mass loss rate was measured when the sample was held at 400°C for 1 hour.

[0087] [Table 1]

[0088] (Consideration) From the results of the above Examples and Comparative Examples, as well as the results of tests conducted by the inventors thus far, it has been found that by selecting a polyetherimide that is incompatible or partially compatible with polyaryletherketone, particularly polyetheretherketone, and producing a film from a resin composition containing both, the film will have at least two glass transition temperatures between 150 and 250°C and the decrease in storage modulus (E') at 150 to 250°C can be suppressed, resulting in excellent heat resistance. Furthermore, even if the film is made thin, for example, less than 200 μm, it is possible to prevent breakage during motor assembly. Therefore, taking this mechanism of action into consideration, it can be considered that a film that contains polyaryletherketone and polyetherimide and has at least two glass transition temperatures between 150 and 250°C will not break during motor assembly and will have excellent heat resistance, regardless of other conditions, even if the film is thin.

Claims

1. A film for motor insulation comprising polyaryletherketone and polyetherimide, and having at least two glass transition temperatures between 150 and 250°C.

2. Storage modulus (E') at 230°C is 1.0 x 10 ８ ~2.0 x 10 ９ The motor insulating film according to claim 1, wherein the modulus of elasticity is 100 Pa.

3. Storage modulus (E') at 190 to 230°C is 1.0 x 10 ８ ~2.0 x 10 ９ The motor insulating film according to claim 1, wherein the modulus of elasticity is 100 Pa.

4. The motor insulating film according to claim 1 , wherein the polyaryletherketone is polyetheretherketone.

5. 2. The motor insulating film according to claim 1, wherein the polyetherimide has a repeating unit represented by the following formula (1):

6. 2. The motor insulating film according to claim 1, having a thickness of 10 μm or more and 200 μm or less.

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

8. 2. The motor insulating film according to claim 1, wherein the dynamic friction coefficient between at least one surface of the film and a stainless steel plate is 0.3 or less.

9. 10. The motor insulating film of claim 1 which is a slotted paper.

10. A motor comprising the motor insulating film according to claim 1.

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