JP2020021626A - Insulation film - Google Patents

Abstract

To provide an insulation film excellent in crack resistance, heat resistance, slidability, and impact resistance to a solvent.SOLUTION: An insulation film contains polyether ether ketone layers with a relative crystallinity of 90% or more, and polyether imide layers. It has the polyether ether ketone layer as both outermost layers.SELECTED DRAWING: None

Description

  The present invention relates to an insulating film using super-engineering plastic, and more particularly to a film that can be suitably used as an insulating film for a motor made of slot paper or wedge paper.

  In recent years, the performance of motors has been improved, and there has been a demand for insulating films for motors having better chemical resistance and heat resistance than before. In addition, in order to prevent breakage during insertion into the motor core, the insulating film is required to have high impact resistance and slidability.

  Super engineering plastics represented by polyetherimide resins and the like are excellent in chemical resistance, heat resistance, and mechanical properties, and thus can be suitably used as insulating films. However, it has been difficult for a single resin to satisfy all the above required characteristics.

  Patent Document 1 discloses a laminated film of a polyetheretherketone resin and a polyetherimide resin, and describes that the film is excellent in chemical resistance and impact resistance. Further, there is a description that the film can be suitably used as a slot paper for a motor (slot liner) by utilizing these characteristics.

  Patent Document 2 discloses a blend of a polyetheretherketone resin, a polyetherimide resin, and an inorganic filler, and describes that the blend can achieve both heat resistance and flexibility.

JP-A-62-148260 JP-A-62-149436

However, the laminated film described in Patent Document 1 does not disclose any specific requirements preferable for use as an insulating film. Furthermore, there is a description that the polyetheretherketone resin layer may be used in either an amorphous state or a crystalline state, but there is no description about a preferable crystallinity for use as an insulating film.
In addition, since the blend described in Patent Document 2 is a compatible system of a polyetheretherketone resin and a polyetherimide resin, it is expected that the physical properties will change in a direction that impairs the individual characteristics of each.

  The present invention has been made under such circumstances, and has an object to provide an insulating film having excellent crack resistance to solvents, heat resistance, slidability, and impact resistance. .

  As a result of intensive studies, the present inventors have succeeded in obtaining an insulating film that can solve the above-described problems of the related art, and have completed the present invention.

  That is, the object of the present invention is solved by an insulating film including a polyetheretherketone layer having a relative degree of crystallinity of 90% or more and a polyetherimide layer, and including the polyetheretherketone layer on both outermost layers. .

  ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to provide the insulating film excellent in the crack resistance with respect to a solvent, heat resistance, slidability, and impact resistance.

The insulating film of the present invention (hereinafter sometimes referred to as “the present film”) includes a polyetheretherketone layer having a relative crystallinity of 90% or more and a polyetherimide layer, It is an insulating film having layers on both outermost layers.
The details will be described below.

[Polyetheretherketone layer]
In the present invention, the polyetheretherketone layer is a layer in which the polyetheretherketone accounts for 50% by mass or more. The content of the polyetheretherketone is preferably at least 60% by mass, more preferably at least 70% by mass, even more preferably at least 80% by mass, particularly preferably at least 90% by mass. It is particularly preferred that 100% by weight is polyetheretherketone. When the polyetheretherketone layer accounts for such a proportion in the polyetheretherketone layer, the film becomes excellent in crack resistance, slidability, and impact resistance to solvents.

  It is important that the relative crystallinity of the polyetheretherketone layer is 90% or more. The relative crystallinity of the polyetheretherketone layer is preferably at least 92%, more preferably at least 94%, even more preferably at least 96%, particularly preferably at least 98%, Particularly preferred is 100%.

  Means for improving the relative crystallinity of the polyetheretherketone layer include a method of heating when brought into contact with a roll, a method of heating in an oven, and the like. These methods may be a method of heating (in-line) during the manufacturing process, or a method of once collecting a film having low crystallinity and then heating (outlining) in a subsequent process. The lower limit of the total heating time is preferably at least 0.1 second, more preferably at least 0.2 second, even more preferably at least 0.3 second. On the other hand, the upper limit is preferably 10 seconds or less, more preferably 5 seconds or less, and even more preferably 3 seconds or less. By setting the heating time within the above range, the relative crystallinity of the polyetheretherketone can be sufficiently improved while maintaining the productivity.

As a means for improving the relative crystallinity of the polyetheretherketone layer, a method using a nucleating agent may be used in addition to the above-described heating method.
The addition of a nucleating agent promotes the generation of crystal nuclei and improves the crystal density, so that the relative crystallinity can be increased.
The lower limit of the amount of the nucleating agent is preferably 0.01% by mass or more, more preferably 0.03% by mass or more, and preferably 0.05% by mass, based on 100% by mass of the polyetheretherketone. More preferably, it is the above. On the other hand, the upper limit is preferably 20% by mass or less, more preferably 10% by mass or less, and even more preferably 5% by mass or less. By setting the amount of the nucleating agent in the above range, the relative crystallinity of the polyetheretherketone can be sufficiently improved while maintaining the mechanical properties of the film.
The nucleating agent is not particularly limited as long as it is generally used as a nucleating agent for a thermoplastic resin.

Furthermore, since the molecular chains are regularly arranged in the stretching direction by stretching the film, the relative crystallinity can be improved. The lower limit of the stretching ratio is preferably 1.1 times or more, more preferably 1.2 times or more, and even more preferably 1.3 times or more. On the other hand, the upper limit is preferably 10 times or less, more preferably 8 times or less, and even more preferably 6 times or less. By setting the stretching ratio in the above range, the relative crystallinity can be sufficiently improved while suppressing breakage of the film in the stretching step.
The stretching direction may be either uniaxial stretching in the vertical or horizontal direction or biaxial stretching in the vertical or horizontal direction. In the case of biaxial stretching, the stretching method may be either sequential biaxial stretching or simultaneous biaxial stretching.

By crystallizing the polymer material, the molecular chains are regularly arranged, so that the solvent cannot enter the inside of the molecular chains, and the crack resistance to the solvent is improved. In manufacturing the motor, there is a step of dropping or dipping varnish as an adhesive in order to fix the coil and the insulating film, and the insulating film may be deteriorated by a solvent component or a low molecular weight component such as a monomer contained in the varnish. In use, there is a concern about deterioration due to hydraulic oil. Deterioration of the insulating film causes cracks and a decrease in molecular weight, leading to a decrease in insulating properties and mechanical properties.
Therefore, in the present invention, the polyetheretherketone layer is disposed on both outermost layers, and by setting the crystallinity of the polyetheretherketone layer within the above range, the polyetherimide layer is deteriorated by the solvent and low molecular weight components. In addition, generation of cracks can be suppressed.

In addition, since the crystallized polymer material has a small ratio of the amorphous portion, when heat is applied from the outside, the ratio of the molecular chains that perform micro-Brownian motion is reduced, and the decrease in the elastic modulus is reduced. Heat resistance is improved. In recent years, the temperature environment at the time of use has become severe with the increase in the output of the motor, and in some cases, continuous use at 150 ° C. or higher has been required. If the heat resistance is low and a dimensional change occurs at a high temperature, the reliability as an insulating film is impaired.
Therefore, in the present invention, the polyetheretherketone layer is disposed on both outermost layers, and the crystallinity of the polyetheretherketone layer is within the above range, thereby maintaining the excellent heat resistance of the polyetherimide resin layer. Is what I was able to do.

Further, when the polymer material is crystallized, the molecular chains become dense and the intermolecular force acts strongly to make the polymer material rigid, so that it becomes difficult to follow the frictional stress from the outside, and as a result, the slidability is improved. When slot paper is inserted in the motor manufacturing process, the slot paper is inserted so as to slide into the core at the same time as the coil. Therefore, poor slidability causes buckling and breakage.
Therefore, in the present invention, the polyetheretherketone layer is disposed on both outermost layers, and the crystallinity of the polyetheretherketone layer is within the above range, whereby excellent slidability can be imparted. It is.

  In the present invention, the relative crystallinity is measured using a differential scanning calorimeter (DSC) in accordance with JIS K7121: 2012. Hereinafter, thermal parameters such as a glass transition temperature, a crystal melting temperature, a heat of crystal fusion, a crystallization temperature, and a heat of crystallization are all measured in accordance with this standard.

The method for measuring the relative crystallinity is not particularly limited as long as it conforms to the above-mentioned standard. For example, the insulating film of the present invention is heated from room temperature to 380 ° C. at a rate of 10 ° C./min. The heat of crystallization ΔHc and the heat of crystal fusion ΔHm are calculated from the exothermic peak area during crystallization of ether ether ketone and the endothermic peak area during crystal melting of polyetheretherketone. Using these, the relative crystallinity is calculated from the following equation.
Relative crystallinity (%) = {(| ΔHm | − | ΔHc |) / ΔHm} × 100

  The polyetheretherketone contained in the polyetheretherketone layer has a repeating unit (a-1) represented by the following structural formula (1). The repeating unit (a-1) has two ether groups and one ketone group.

  The lower limit of the total number (degree of polymerization) of the repeating units (a-1) of the polyetheretherketone is preferably 10 or more, and more preferably 20 or more. On the other hand, the upper limit is preferably 500 or less, more preferably 100 or less. When the total number (degree of polymerization) of the repeating units (a-1) of the polyetheretherketone resin is in such a range, the insulating film of the present invention is excellent in crack resistance, heat resistance, and impact resistance to solvents. Since the viscosity at the time of melting is not too high, the melt moldability is excellent.

  The lower limit of the heat of crystal fusion of the polyetheretherketone is preferably at least 20 J / g, more preferably at least 25 J / g, even more preferably at least 30 J / g. On the other hand, the upper limit is preferably 60 J / g or less, more preferably 55 J / g or less, and even more preferably 50 J / g or less. When the heat of fusion of crystal of polyetheretherketone is within such a range, the insulating film of the present invention is excellent in heat resistance and requires only a small amount of heat energy to be applied during melt molding, so that it is excellent in melt moldability.

  The lower limit of the crystal melting temperature of the polyetheretherketone is preferably 300 ° C. or higher, more preferably 320 ° C. or higher, even more preferably 340 ° C. or higher. On the other hand, the upper limit is preferably 400 ° C. or lower, more preferably 380 ° C. or lower, even more preferably 360 ° C. or lower. As long as the crystal melting temperature of the polyetheretherketone is within the above range, the insulating film of the present invention has excellent heat resistance and also has excellent melt moldability because the viscosity at the time of melting is not too high.

  The lower limit of the glass transition temperature of the polyetheretherketone is preferably 120 ° C. or higher, more preferably 140 ° C. or higher. On the other hand, the upper limit is preferably 200 ° C. or lower, more preferably 180 ° C. or lower. When the glass transition temperature of the polyetheretherketone is within such a range, the insulating film of the present invention is excellent in heat resistance and also excellent in melt moldability because the viscosity at the time of melting is not too high.

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

[Polyetherimide layer]
In the present invention, the polyetherimide layer is a layer in which polyetherketone accounts for 50% by mass or more. The polyether ketone content is preferably at least 60% by mass, more preferably at least 70% by mass. When the polyetherimide layer contains the polyetherimide at such a ratio, the insulating film of the present invention has excellent heat resistance.

  The polyetherimide contained in the polyetherimide layer includes a repeating unit (b-1) represented by the following structural formula (2) or a repeating unit (b-2) represented by the following structural formula (3). Have.

  In general, the structure of polyetherimide is classified according to the difference in bonding mode, that is, the difference between meta bond and para bond, and the mechanical properties and heat resistance are different from each other. When blended with polyetheretherketone, the polyetherimide represented by Structural Formula (2) is compatible, while the polyetherimide represented by Structural Formula (3) is partially compatible. It has been known.

  The lower limit of the total number (degree of polymerization) of the repeating units (b-1) or (b-2) of the polyetherimide is preferably 10 or more, and more preferably 20 or more. On the other hand, the upper limit is preferably 1,000 or less, more preferably 500 or less. When the total number (degree of polymerization) of the repeating units (b-1) or (b-2) of the polyetherimide is within such a range, the insulating film of the present invention is excellent in heat resistance and has too high a viscosity at the time of melting. Excellent in melt moldability because there is no.

  The lower limit of the glass transition temperature of the polyetherimide is preferably 140 ° C. or higher, more preferably 160 ° C. or higher, and further preferably 180 ° C. or higher. On the other hand, the upper limit is preferably 300 ° C. or lower, more preferably 280 ° C. or lower, and further preferably 260 ° C. or lower. When the glass transition temperature of the polyetherimide is within such a range, the insulating film of the present invention is excellent in heat resistance and also excellent in melt moldability because the viscosity at the time of melting is not too high.

  The polyetherimide layer may include polyetheretherketone. In this case, the lower limit of the polyether imide ketone in the polyether imide layer is preferably 1% by mass or more, more preferably 5% by mass or more, even more preferably 10% by mass or more. On the other hand, the upper limit is preferably 50% by mass or less, more preferably 40% by mass or less, and even more preferably 30% by mass or less.

  Since polyetheretherketone and polyetherimide are compatible or partially compatible with each other, when they are mixed, they are not phase-separated or are in a finely dispersed state even after phase-separation. Therefore, by mixing the polyetheretherketone and the polyetherimide, there is no possibility that the mechanical properties are deteriorated due to the phase interface. On the contrary, when the polyetherimide layer contains the polyetheretherketone in a proportion of 1% by mass or more, the crack resistance and the impact resistance of the polyetherimide layer with respect to the solvent resistance can be improved. Further, when the polyetherimide layer contains polyetheretherketone at a ratio of 50% by mass or less, the glass transition temperature of the polyetherimide layer can be maintained at a high level, and the heat resistance can be maintained. .

  The polyetherimide can be produced by a known production method. Also, commercially available products can be used. Examples of commercially available products include “Ultem” series manufactured by Subic.

[Insulating film]
This film is a film that includes a polyetheretherketone layer having a relative crystallinity of 90% or more and a polyetherimide layer, and the polyetheretherketone layer is provided on both outermost layers. By adopting such a configuration, the present film can have a good balance of crack resistance, heat resistance, slidability, and impact resistance to a solvent.

The layer structure of this film is (A) / (B) / (A) when the polyetheretherketone layer is (A), the polyetheretherketone layer is (B), and the other layers are (C). Two types and three layers such as (A) / (B) / (C) / (A), and three types and four layers such as (A) / (B) / (A) / (B) / (A) ), (A) / (B) / (C) / (B) / (A), (A) / (C) / (B) / (C) / (A) Any of such three types and five layers may be used.
Here, examples of the layer (C) include an adhesive layer, and commonly used hot melt adhesives, epoxy adhesives, silicone adhesives, acrylic adhesives, urethane adhesives, and the like. Can be used.

  Among the above-mentioned layer configurations, it is preferable to have a laminated structure of two and three layers in which a polyetheretherketone layer is provided in both outermost layers and the polyetherimide layer is provided in an intermediate layer. Since the polyetheretherketone and the polyetherimide are mutually compatible or partially compatible as described above, it is assumed that the polyetheretherketone layer and the polyetherimide layer are directly bonded without interposing an adhesive layer between the layers. This is because strong interlayer adhesion strength can be obtained.

  The ratio of the thickness of the polyetheretherketone layer in the film is preferably 20% or more and 50% or less. When the ratio of the thickness of the polyetheretherketone layer in the film is within the above range, the film has excellent crack resistance and impact resistance to a solvent because the thickness of the polyetheretherketone layer is sufficient, Since the thickness of the ether imide layer is sufficient, it has excellent heat resistance at high temperatures.

  This film has a tensile modulus at 200 ° C. of preferably 500 MPa or more, more preferably 600 MPa or more, still more preferably 700 MPa or more, as measured according to JIS K7244-4: 1999, It is particularly preferably at least 800 MPa, particularly preferably at least 1000 MPa. As long as the tensile modulus at 200 ° C. of the film is within the above range, the film has excellent heat resistance at high temperatures. By providing the intermediate layer with a polyetherimide having a high glass transition temperature and excellent heat resistance at a high temperature, the tensile modulus can be adjusted to be high.

  This film preferably has a dynamic friction coefficient of 0.20 or less, more preferably 0.19 or less, and even more preferably 0.18 or less, as measured in accordance with JIS K7125: 1999. When the dynamic friction coefficient of the film is within the above range, the film can be easily inserted into the motor core, and buckling and breakage during insertion can be prevented. By providing polyetheretherketone in both outermost layers and further increasing the relative crystallinity, the dynamic friction coefficient can be reduced.

  This film preferably has a puncture impact strength at a thickness of 100 μm of 1.0 J or more, more preferably 1.1 J or more, and more preferably 1.2 J or more, measured according to JIS K7124-2: 1999. Is more preferable, and it is especially preferable that it is 1.2 J or more, and it is especially preferable that it is 1.4 J or more. As long as the puncture impact strength is within the range where the thickness of the film is 100 μm, breakage at the time of insertion into a motor core or at the time of bending secondary processing can be prevented. By providing a polyetheretherketone having excellent puncture impact strength in both outermost layers, a high adjustment can be achieved.

  This film preferably has a bending strength at a thickness of 100 μm of 100 times or more, more preferably 120 times or more, still more preferably 140 times or more, measured according to JIS P8115, and more preferably 160 times or more. It is particularly preferable that the number of times is at least 180 times, and it is particularly preferable that the number of times is 180 times or more. If the thickness of the film is 100 μm and the bending strength is within the range, it is possible to prevent breakage at the time of insertion into the motor core or at the time of bending secondary processing. By providing polyetheretherketone having excellent bending strength in both outermost layers, the bending strength can be adjusted to be high.

  The lower limit of the thickness of the film is preferably 50 μm or more, more preferably 100 μm or more, further preferably 150 μm or more, and particularly preferably 200 μm or more. On the other hand, the upper limit is preferably 500 μm or less, more preferably 450 μm or less, further preferably 400 μm or less, and particularly preferably 350 μm or less. When the thickness is 50 μm or more, the present film has sufficient insulating properties and rigidity, and can prevent current leakage during use and buckling during insertion. If the thickness is 500 μm or less, the density of the coil inserted into the motor core can be increased, and the motor efficiency can be maintained high.

  In addition, this film may be any of heat stabilizers, antioxidants, ultraviolet absorbers, light stabilizers, antibacterial and antifungal agents, antistatic agents, lubricants, pigments, dyes, and the like, as long as the effects of the present invention are not impaired. Additives may be included.

[Production method]
The film can be produced by a general molding method, for example, extrusion molding, injection molding, blow molding, vacuum molding, air pressure molding, press molding and the like. In each molding method, the apparatus and processing conditions are not particularly limited, but from the viewpoint of productivity and thickness control, extrusion molding, particularly, T-die method is preferable.

  The method for producing the insulating film of the present invention is not particularly limited, but for example, the constituent material of the film can be obtained as a non-stretched or stretched film, and is preferably obtained as a non-stretched film from the viewpoint of secondary workability. In addition, a non-stretched film is a film which is not actively stretched for the purpose of controlling the orientation of a sheet, and includes a film which is oriented when it is taken up by a cast roll by a T-die method.

  In the case of a non-stretched film, for example, it can be produced by melt-kneading the constituent materials, extruding, and cooling. For the melt kneading, a known kneader such as a single screw or twin screw extruder can be used. The melting temperature is appropriately adjusted depending on the type and mixing ratio of the resin, the presence or absence and the type of the additive, but from the viewpoint of productivity and the like, is preferably 320 ° C or higher, more preferably 330 ° C or higher. . Further, the temperature is preferably 400 ° C or lower, more preferably 380 ° C or lower. The molding can be performed, for example, by extrusion using a mold such as a T-die.

  When manufacturing a laminated film, a co-extrusion method in which the resin composition of each layer is co-extruded and laminated, an extruded lamination method in which each layer is formed into a film shape, and this is laminated, each layer is formed into a film shape, and these are heated Although the molding may be performed by any of the thermocompression bonding methods, compression molding is preferable from the viewpoint of productivity. The co-extrusion method includes a multi-manifold method in which the resin compositions of the respective layers are joined by a die, a feed block method in which the resin compositions are joined by a feed block, and the like, and any of them may be used.

  In this film, it is important that the polyetheretherketone layer is crystallized to some extent. For example, the polyetheretherketone layer can be crystallized by heat-treating the film. As a method of crystallization, an in-line method of heating a molten resin at a predetermined temperature or more and solidifying while crystallizing, and once solidifying in an amorphous state and heating at a predetermined temperature or more in a subsequent process. Although there is an outline method for solidification, it is preferable to use an in-line method from the viewpoint of productivity. In particular, when the T-die method is used, it can be crystallized with a cast roll, and the temperature at that time is preferably 180 ° C or higher and 240 ° C or lower, more preferably 190 ° C or higher and 230 ° C or lower. , 200 ° C or more and 220 ° C or less. If the temperature at the time of crystallization is 180 ° C. or higher, crystallization proceeds promptly, so that sticking to a cast roll is suppressed, and as a result, thickness accuracy and film appearance are favorable. Further, when the temperature during crystallization is 240 ° C. or lower, not only crystallization proceeds rapidly, but also the temperature during crystallization can be lowered, which leads to energy saving.

  The cooling method in the case of using the outline method can be performed, for example, by bringing the molded article into contact with a cooler such as a cooled cast roll and rapidly cooling the molded article. Thereby, the molded product is solidified, and a non-stretched film is obtained. The cooling temperature is not limited as long as it is lower than the melting temperature, but is preferably 160 ° C. or lower, more preferably 150 ° C. or lower. The temperature is preferably 120 ° C. or higher, more preferably 130 ° C. or higher.

[Usage and usage mode]
The insulating film of the present invention is excellent in crack resistance, heat resistance, impact resistance, and slidability with respect to solvents, so that it is used in home appliances, audio equipment, IT equipment, communication equipment, OA equipment, medical equipment, health care equipment, and business. It can be suitably used as an insulating film for motors for use in equipment, industrial equipment, transportation equipment such as automobiles, railways and ships.
In particular, slot paper and wedge paper made of this film are suitable for use without any problem of insulation failure because they do not easily undergo impact deformation or cracking when molding or inserting into slot paper or wedge paper from film. You can do it.

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

1. Production of Film In the Examples and Comparative Examples, films having the composition shown in Table 1 below were produced using the following raw materials.

<Polyetheretherketone>
(A) -1: VESTAKEEP 3300G (manufactured by Daicel Evonik Co., Ltd., repeating unit of (a-1), heat of crystal fusion = 41 J / g, crystal melting temperature = 343 ° C., glass transition temperature = 143 ° C.)

<Polyetherimide>
(B) -1: Ultem 1000-1000 (manufactured by Difference Big Co., a repeating unit of (b-1), glass transition temperature = 217 ° C.)
(B) -2: Ultem CRS5001-1000 (manufactured by Subic Corporation, repeating unit of (b-2), glass transition temperature = 227 ° C.)

(Example 1)
(A) -1 was used as a raw material for the polyetheretherketone layer, and (B) -1 was used as a raw material for the polyetherimide layer. These are melted separately using two Φ40 mm extruders, and the polyetheretherketone layer is divided into halves by a feed block, and the polyetheretherketone layer / polyetherimide layer / polyetheretherketone layer is divided. It is laminated in a feed block so as to be in order and extruded from a T-die as a laminated film of two types and three layers, and in order to crystallize both outermost layers, it is brought into close contact with a cast roll at 210 ° C. A laminated film was obtained so that the ratio was 8/1 (the thickness ratio of the polyetheretherketone layer in the entire film = 20%). At this time, the extruder temperature of the polyetheretherketone layer, the extruder temperature of the polyetherimide layer, the temperature of the feed block, and the temperature of the die were all set to 380 ° C.
Laminated films having a thickness of 300 μm and a thickness of 100 μm and having a two-layer configuration of three layers were prepared. For a film having a thickness of 300 μm, a solvent crack test, a tensile modulus at 200 ° C., and a dynamic friction coefficient were evaluated. On the other hand, a film having a thickness of 100 μm was evaluated for puncture impact strength and bending strength. Table 1 shows the results.

(Example 2)
Except that the number of rotations of the extruder of the polyetheretherketone layer and the polyetherimide layer was adjusted, and the lamination ratio was changed to 1/4/1 (the thickness ratio of the polyetheretherketone layer in the entire film = 33%). A sample was prepared in the same manner as in Example 1. Table 1 shows the evaluation results.

(Example 3)
Except that the number of rotations of the extruder for the polyetheretherketone layer and the polyetherimide layer was adjusted and the lamination ratio was changed to 1/4/1 (the thickness ratio of the polyetheretherketone layer to the entire film = 50%). A sample was prepared in the same manner as in Example 1. Table 1 shows the evaluation results.

(Example 4)
A sample was prepared in the same manner as in Example 1 except that (B) -2 was used instead of (B) -1 as a raw material for the polyetherimide layer. Table 1 shows the evaluation results.

(Example 5)
A sample was prepared in the same manner as in Example 1, except that a mixture of (A) -1 and (B) -1 in a mixing mass ratio of 80: 20% by mass was used as a raw material for the polyetherimide layer. Table 1 shows the evaluation results.

(Comparative Example 1)
A sample was produced in the same manner as in Example 1 except that the cast roll temperature was set to 130 ° C. and the film was collected in a state where the crystallinity of the polyetheretherketone layer was low. Table 1 shows the evaluation results.

(Comparative Example 2)
A polyether ether ketone single-layer film was obtained under the same conditions as in Example 1 except that only one extruder was used and (A) -1 was used as a raw material. This film was evaluated in the same manner as in Example 1. Table 1 shows the results.

(Comparative Example 3)
A polyetherimide single layer film was obtained under the same conditions as in Example 1 except that only one extruder was used and (B) -1 was used as a raw material. This film was evaluated in the same manner as in Example 1. Table 1 shows the results.

2. Evaluation of Film The films manufactured in the above Examples and Comparative Examples were evaluated and measured for various items as follows. Here, the “longitudinal” of the film refers to a direction in which the film-shaped molded product is extruded from the T-die, and a direction orthogonal to the direction in the film plane is defined as “horizontal”.

(1) Crystallinity of the phase of the polyether ether ketone layer The temperature of each film was raised from room temperature to 380 ° C. at a rate of 10 ° C./min. The heat of crystallization ΔHc and the heat of crystal fusion ΔHm are calculated from the endothermic peak area during crystal melting of the ketone. Using these, the relative crystallinity was calculated from the following equation.
Relative crystallinity (%) = {(| ΔHm | − | ΔHc |) / ΔHm} × 100

(2) Solvent crack test Each film having a thickness of 300 μm was cut into a length of 60 mm and a width of 9 mm to prepare a test piece. The film was bent so as to fit at a position of 20 mm from each end of the film in the longitudinal direction, and fixed with a double clip. In this state, the film was immersed in a styrene monomer for 2 minutes, taken out and dried, and the appearance of the film was evaluated. Those in which cracks could not be confirmed were passed (（), and those in which cracks could be confirmed were rejected (X).

(3) Tensile modulus (200 ° C)
For each film having a thickness of 300 μm, using a viscoelastic spectrometer DVA-200 (manufactured by IT Measurement Control Co., Ltd.) in accordance with JIS K7244-4: 1999, strain 0.1%, frequency 10 Hz, heating rate The temperature dispersion of dynamic viscoelasticity was measured at 3 ° C./min, and the tensile modulus at 200 ° C. was evaluated. Those having a tensile modulus at 200 ° C. of 500 MPa or more were evaluated as acceptable (○), and those having a tensile modulus of less than 500 MPa were evaluated as unacceptable (×).

(4) Dynamic friction coefficient
The dynamic friction coefficient of each film having a thickness of 300 μm was evaluated using a plastic film slip tester (Intesco) in accordance with JIS K7125: 1999. Those with a kinetic friction coefficient of 0.20 or less were evaluated as acceptable (○), and those with a dynamic friction coefficient exceeding 0.20 were evaluated as unacceptable (x).

(5) Puncture Impact Strength For each film having a thickness of 100 μm, using a high-speed puncture impact tester Hydroshot HITS-P10 (Shimadzu Corporation) at 23 ° C. and − in accordance with JIS K7124-2: 1999. The measurement was performed under a temperature environment of 20 ° C. under the conditions of a punching diameter of 0.5 inch and a test speed of 3 m / sec. Those having a puncture impact strength of 1.0 or more were evaluated as acceptable (（), and those having a puncture impact strength less than 1.0 were evaluated as unacceptable (x).

(6) Folding strength
For each film having a thickness of 100 μm, the bending strength was measured using an MIT bending fatigue tester (Toyo Seiki) in accordance with JIS P8115. Those with a bending strength of 100 times or more passed (o), and those with less than 100 times failed (x).

The laminated films obtained in Examples 1 to 4 had no cracks even by the solvent crack test. In addition, since the kinetic friction coefficient is 0.20 or less, the slidability is excellent. Furthermore, the values of the puncture impact strength and the bending resistance were high, and the impact resistance was excellent. These effects are attributable to the film of the present invention in which polyetheretherketone layers having high crystallinity are disposed on both outermost layers.
In addition, the laminated films obtained in Examples 1 to 4 sufficiently exhibited the effect of heat resistance of the polyetherimide layer, and maintained a high elastic modulus at a high temperature of 200 ° C, and were excellent in heat resistance. .
It can be seen that Example 5 has higher values of puncture impact strength and bending resistance than Example 1, and also has excellent impact resistance. It is considered that since the polyether imide layer contains polyether ether ketone, the impact resistance of the polyether imide layer is improved, and as a result, the impact resistance of the entire laminated film is also improved.
From the above results, it is understood that the insulating film of the present invention has excellent crack resistance, heat resistance, slidability, and impact resistance to solvents.

On the other hand, in Comparative Example 1, cracks occurred in the solvent crack test, and the slidability was poor.
In Comparative Example 2, the sample was excellent in crack resistance, slidability, and impact resistance to a solvent, but the elastic modulus was significantly reduced at 200 ° C. Therefore, it cannot be said that it has heat resistance enough to withstand continuous use at high temperatures.
In Comparative Example 3, although excellent in heat resistance, crack resistance, slidability and impact resistance to a solvent are not sufficient.

Claims (10)

  An insulating film including a polyetheretherketone layer having a relative crystallinity of 90% or more and a polyetherimide layer, wherein the polyetheretherketone layer is provided on both outermost layers.   2. The insulating film according to claim 1, wherein the insulating film has a two-layer, three-layer structure in which the polyetheretherketone layer is provided on both outermost layers and the polyetherimide layer is provided on an intermediate layer.   The insulating film according to claim 1, wherein a ratio of a thickness of the polyetheretherketone layer to a motor insulating film is 20% or more and 50% or less.   The insulating film according to any one of claims 1 to 3, wherein a tensile modulus at 200 ° C is 500 MPa or more.   The insulating film according to any one of claims 1 to 4, having a dynamic friction coefficient of 0.20 or less.   The insulating film according to any one of claims 1 to 5, wherein a puncture impact strength at a thickness of 100 µm is 1.0 J or more.   The insulating film according to any one of claims 1 to 6, wherein the bending strength at a thickness of 100 µm is 100 times or more.   The insulating film according to any one of claims 1 to 7, wherein the thickness is 50 µm or more and 500 µm or less.   A slot paper comprising the insulating film according to any one of claims 1 to 8.   A wedge paper comprising the insulating film according to claim 1.