Insulating film for motor and motor

Abstract

The present invention addresses the problem of providing an insulating film for a motor having high thermal conductivity (heat flow-through property) in addition to excellent assemblability and insulation property. The present invention relates to an insulating film for a motor, comprising a resin layer and aramid paper laminated on both surfaces of the resin layer with an adhesive layer interposed therebetween, wherein the insulating film for a motor has a thickness of 200 μm or less and a density of 1.0 g / cm3 or more, the aramid paper has a thickness of 49 μm or less and a density of 0.65 g / cm3 or more and 1.50 g / cm3 or less, and a value obtained by dividing the thickness of the resin layer by the total thickness of the aramid paper is 0.4-5.

Description

Insulating film for motors and motors

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

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

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

[0004] In recent years, there has been a demand for compact, highly efficient motors. To this end, methods have been considered, such as reducing the thickness of insulating films to increase the space factor of winding coils. For example, Patent Document 2 discloses an aramid-resin film laminate formed by laminating aramid paper and a resin film, in which one side of the aramid paper is plasma-treated under predetermined conditions, and the plasma-treated side and the plasma-treated side of the resin film are joined together and bonded by heating, pressing, or heating and pressing. Patent Document 3 also discloses an insulating sheet for electric motors that includes an aromatic polymer film directly pressure-laminated to aramid paper, obtained by subjecting at least one surface of the aramid paper or the aromatic polymer film to plasma treatment and bonding. Patent Document 4 also discloses an aramid-polyester laminate formed by directly thermally bonding low-temperature plasma-treated aramid paper to a polyester film.

[0005] JP 2022-185658 A JP 2013-223962 A JP 2011-4565 A JP 2008-7875 A

[0006] In recent years, motors have become increasingly smaller, which has led to a demand for thinner insulating films. However, simply making the insulating film thinner can result in insufficient film strength, which can lead to tearing or deformation of the insulating film when it is assembled with wires inside the motor, making assembly difficult. Furthermore, making the insulating film thinner can also result in a decrease in insulation properties, which has been a problem.

[0007] As described above, insulating films are required to have excellent assembly properties and insulation properties, while also having high thermal conductivity (heat transmission properties) to diffuse the heat generated by the motor. With conventional technologies, it has been difficult to achieve high thermal conductivity (heat transmission properties) in addition to excellent assembly properties and insulation properties, and there has been a demand for the development of insulating films that combine these various properties.

[0008] Therefore, in order to solve these problems of the conventional technology, the present inventors have conducted research with the aim of providing an insulating film for motors that combines high thermal conductivity (heat transmittance) in addition to excellent assembly properties and insulating properties.

[0009] Examples of specific embodiments of the present invention are given below.

[0010] [1] An insulating film for a motor comprising a resin layer and aramid paper laminated on both sides of the resin layer via an adhesive layer, wherein the insulating film for a motor has a thickness of 200 μm or less and a density of 1.0 g / cm ３ or more, the thickness of the aramid paper is 49 μm or less, and the density is 0.65 g / cm ３ 1.50g / cm or more ３ [2] An insulating film for a motor, comprising a resin layer and aramid paper laminated on both sides of the resin layer, wherein the density of the insulating film for a motor is 1.2 g / cm or less, and the value obtained by dividing the thickness of the resin layer by the total thickness of the aramid paper is 0.4 to 5. ３ or more, and the density of the aramid paper is 0.7 g / cm３ 1.50g / cm or more ３ An insulating film for a motor, wherein the thickness of the resin layer is 0.4 to 5. [3] The insulating film for a motor according to [1] or [2], wherein the dielectric breakdown strength is 50 kV / mm or more. [4] The insulating film for a motor according to any one of [1] to [3], wherein the compressive strength is 100 N or more. [5] The insulating film for a motor according to any one of [1] to [4], wherein the thickness of at least one aramid paper is 49 μm or less. [6] The insulating film for a motor according to any one of [1] to [5], wherein the thickness of the resin layer is 30 μm or more. [7] The insulating film for a motor according to any one of [1] to [6], wherein the resin layer is at least one selected from the group consisting of polyetherimide, polyether ether ketone, polyimide, polyphenylene sulfide, polyethylene naphthalate, and polyethylene terephthalate. [8] The insulating film for a motor according to any one of [2] to [7], wherein the insulating film has an interface structure in which a portion of the aramid paper is embedded in the resin layer. [9] The insulating film for a motor according to any one of [2] to [8], wherein aramid paper is fused to the resin layer.

[10] The insulating film for a motor according to any one of [1] to [9], wherein the insulating film is slotted paper.

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

[10] .

[0011] According to the present invention, it is possible to provide an insulating film for a motor that has high thermal conductivity (heat transmission) in addition to excellent assembly properties and insulating properties.

[0012] Fig. 1 is a cross-sectional view illustrating the configuration of an insulating film for a motor according to this embodiment. Fig. 2 is a diagram illustrating a rectangular film sample for creating a slotted paper-shaped test piece during a motor assembly test in an example. Fig. 3 is a diagram illustrating the configuration of an assembly jig used in a motor assembly test in an example. Fig. 4 is a diagram illustrating the state of the assembly jig and the copper wire bundle during a motor assembly test in an example, viewed from above the jig.

[0013] The present invention will be described in detail below. The following description may be based on representative embodiments or specific examples, but the present invention is not limited to such embodiments. In this specification, when "X to Y" (X and Y are arbitrary numbers) is used, it means "X or more and Y or less," unless otherwise specified, and also includes "preferably greater than X" or "preferably smaller than Y." Furthermore, when "X or more" (X is an arbitrary number) or "Y or less" (Y is an arbitrary number), it also includes the meaning "preferably greater than X" or "preferably less than Y." In the following description, the terms "film" and "sheet" are not clearly distinguished from each other, and the term "film" includes the term "sheet," and the term "sheet" includes the term "film."

[0014] (Insulating Film for Motors) A first embodiment of the present invention relates to an insulating film for motors (hereinafter, sometimes referred to as "insulating film of the present invention") that includes a resin layer and aramid paper laminated on both sides of the resin layer via adhesive layers. In this embodiment, the insulating film for motors has a thickness of 200 μm or less and a density of 1.0 g / cm ３ or more, the thickness of the aramid paper is 49 μm or less, and the density is 0.65 g / cm ３ 1.50g / cm or more ３ The value obtained by dividing the thickness of the resin layer by the total thickness of the aramid paper is 0.4 to 5.

[0015] A second embodiment of the present invention relates to an insulating film for a motor (hereinafter, sometimes referred to as "the insulating film") that includes a resin layer and aramid paper laminated on both sides of the resin layer. In this embodiment, the insulating film for a motor has a density of 1.2 g / cm. ３ or more, and the density of the aramid paper is 0.7 g / cm ３ 1.50g / cm or more ３ or less, and the value obtained by dividing the thickness of the resin layer by the total thickness of the aramid paper is 0.4 to 5. In the second embodiment, it is preferable that the resin layer and the aramid paper are directly laminated, and it is preferable that the aramid paper is fused (thermally fused) to the resin layer.

[0016] In this embodiment, the aramid paper is preferably laminated on both sides of the resin layer. FIG. 1 discloses an insulating film 10 for a motor in which aramid paper 4 is laminated on both sides of a resin layer 2. In this embodiment, as shown in FIG. 1( b), the resin layer 2 and the aramid paper 4 may be laminated via an adhesive layer 6 (first embodiment). In this case, by setting the thickness and density of the aramid paper within the above-described ranges and further setting the value obtained by dividing the thickness of the resin layer by the total thickness of the aramid paper within a predetermined range, it becomes easier to reduce the thickness of the insulating film. In this embodiment, the resin layer 2 and the aramid paper 4 may be directly laminated as shown in FIG. 1( a). In this case, the insulating film 10 for a motor has a configuration in which the aramid paper 4, the resin layer 2, and the aramid paper 4 are laminated in this order (second embodiment). Furthermore, when the resin layer 2 and the aramid paper 4 are directly laminated, it is preferable that the aramid paper 4 be fused to the resin layer 2. When the resin layer 2 and the aramid paper 4 are directly laminated, it becomes easier to reduce the thickness of the insulating film.

[0017] In addition, when the resin layer and the aramid paper are directly laminated, a portion of the resin constituting the resin layer may be impregnated into the aramid paper in the process of forming the present insulating film. In such a case, the present insulating film may have a configuration in which aramid paper impregnated with a portion of the resin constituting the resin layer, the resin layer, and aramid paper impregnated with a portion of the resin constituting the resin layer are laminated in this order. More specifically, the interface structure between the resin layer and the aramid paper preferably has an interface structure in which a portion of the aramid paper is embedded in the resin layer.

[0018] The density of this insulating film is 1.0 g / cm ３ It is preferable that the density is 1.05 g / cm or more. ３ More preferably, it is 1.1 g / cm or more. ３ More preferably, it is 1.15 g / cm or more. ３ More preferably, it is 1.2 g / cm or more. ３ It is more preferable that the value is 1.25 g / cm or more. ３ It is even more preferable that the value is 1.3 g / cm or more. ３In particular, in the first embodiment, the density of the insulating film is preferably 1.0 g / cm or more. ３ In the first embodiment, the density of the insulating film is preferably 1.2 g / cm or more. ３ The upper limit of the density of the insulating film is not particularly limited, but is usually 3.0 g / cm ３ In this embodiment, by setting the density of the insulating film to be equal to or greater than the above-mentioned lower limit, it is possible to more effectively improve the insulating properties and ease of assembly. Furthermore, by setting the density of the insulating film to be equal to or greater than the above-mentioned lower limit, it is possible to more effectively increase the thermal conductivity (heat transmission) of the insulating film, and to quickly diffuse the heat generated by the motor.

[0019] The thickness (total thickness) of the present insulating film is preferably 200 μm or less, more preferably 180 μm or less, even more preferably 170 μm or less, even more preferably 160 μm or less, even more preferably 150 μm or less, even more preferably 140 μm or less, particularly preferably 135 μm or less, and most preferably 130 μm or less. The thickness of the present insulating film is preferably 36 μm or more, more preferably 40 μm or more, even more preferably 45 μm or more, and particularly preferably 50 μm or more. In this embodiment, by setting the thickness of the insulating film to the above upper limit or less, a thinner insulating film can be achieved, thereby increasing the coil space factor in the motor and improving motor efficiency. Furthermore, by setting the thickness of the insulating film to the above upper limit or less, the thermal conductivity (heat transmission) of the insulating film can be more effectively improved. On the other hand, by setting the thickness of the insulating film to the above lower limit or more, the insulating properties of the insulating film can be more effectively improved. Furthermore, by setting the thickness of the insulating film to the above lower limit or more, the strength of the insulating film can be increased, and the assembling property can be improved.

[0020] The overall thickness of the insulating film can be calculated by cutting the film into 10 cm square pieces, measuring the thickness at nine points at 50 mm intervals with a dial gauge, and averaging the measured values. From the viewpoint of thinning, the maximum thickness of the nine measured points is preferably 210 μm or less, more preferably 200 μm or less, even more preferably 190 μm or less, still more preferably 180 μm or less, even more preferably 170 μm or less, still more preferably 160 μm or less, even more preferably 150 μm or less, particularly preferably 145 μm or less, and most preferably 140 μm or less.

[0021] In this insulating film, the value obtained by dividing the thickness of the resin layer by the total thickness of the aramid paper (resin layer thickness / total aramid paper thickness) is preferably 0.3 or more, more preferably 0.35 or more, even more preferably 0.4 or more, even more preferably 0.45 or more, and particularly preferably 0.5 or more. Furthermore, the value obtained by dividing the thickness of the resin layer by the total thickness of the aramid paper (resin layer thickness / total aramid paper thickness) is preferably 5 or less, more preferably 4.5 or less, even more preferably 4 or less, even more preferably 3.5 or less, and particularly preferably 3 or less. By setting the value of resin layer thickness / total aramid paper thickness within the above range, it becomes easier to control the density of the insulating film within the desired range, thereby more effectively improving the insulating properties of the insulating film. Furthermore, by setting the thickness ratio of the aramid paper to the resin layer within the above range, the thermal conductivity (heat transmission) of the insulating film can be more effectively improved. Furthermore, by setting the thickness ratio of the aramid paper to the resin layer within the above range, the strength of the insulating film can be increased, improving assembly ease.

[0022] The dielectric breakdown strength of the present insulating film is preferably 50 kV / mm or more, more preferably 70 kV / mm or more, and even more preferably 100 kV / mm or more. The upper limit of the dielectric breakdown strength of the present insulating film is not particularly limited, but is preferably 300 kV / mm or less, for example. If the dielectric breakdown strength of the present insulating film is equal to or greater than the lower limit, the insulating properties of the insulating film can be determined to be good. The dielectric breakdown strength of the insulating film can be measured using a dielectric breakdown tester. Specifically, the motor insulating film is sandwiched between two electrodes (φ6 mm) of the dielectric breakdown tester, and the voltage is increased from 0 in air at a constant rate so that dielectric breakdown occurs in an average of 10 to 20 seconds. The voltage at which the test material breaks down can be calculated by dividing the voltage by the thickness.

[0023] The compressive strength of the insulating film is preferably 100 N or more, more preferably 120 N or more, and even more preferably 140 N or more. The upper limit of the compressive strength of the insulating film is not particularly limited, but is usually 1000 N or less. It is preferable that the compressive strength of the insulating film in at least one direction be within the above range. For example, it is preferable that the compressive strength in the machine direction (MD) be within the above range. If the compressive strength of the insulating film is equal to or greater than the above lower limit, buckling of the insulating film can be suppressed when the insulating film is inserted into a motor, thereby more effectively improving workability during assembly.

[0024] The compressive strength of an insulating film is a value measured by the following method. First, the insulating film is cut into a strip film having a width of 12.7 mm (longitudinal direction) and a length of 157 mm (transverse direction), and the strip film is rolled in the longitudinal direction to prepare a longitudinal direction (MD) test piece. After placing the test piece on a test piece holder, a precision universal testing machine is used to operate the test piece until it is crushed, and the maximum compressive force at the time of crushing is measured and used as the compressive strength.

[0025] In this embodiment, the density of the insulating film, the density of the aramid paper, and the value obtained by dividing the thickness of the resin layer by the total thickness of the aramid paper are set within a predetermined range, thereby successfully achieving a thin overall thickness of the insulating film while maintaining both electrical insulation and thermal conductivity (heat transmission). Furthermore, in this embodiment, the thermal conductivity (heat transmission) can be more effectively improved by considering the balance between the thicknesses of the resin layer and the aramid paper. In particular, in the first embodiment, the thickness of the aramid paper is set to a predetermined value or less, thereby reducing the overall thickness of the insulating film and increasing the thickness ratio of the resin layer, thereby easily achieving both electrical insulation and thermal conductivity (heat transmission). Furthermore, in the second embodiment, the density of the insulating film and the density of the aramid paper are further limited, thereby achieving a thin overall thickness of the insulating film while maintaining both electrical insulation and thermal conductivity (heat transmission).

[0026] Furthermore, in this embodiment, the density of the insulating film is set to a predetermined value or higher and aramid paper is laminated on both sides of the resin layer, thereby successfully improving the assembly ease of the insulating film. By setting the density of the insulating film to a predetermined value or higher and laminating aramid paper on both sides of the resin layer, scratching, tearing, deformation, etc. of the insulating film due to friction with the core material or wire during assembly can be prevented, and scratching, tearing, and deformation of the insulating film due to load from the coil after assembly can be prevented. Since scratching, tearing, deformation, etc. of the insulating film during assembly can cause insulation defects, improving the assembly ease of the insulating film can more effectively improve insulation. The assembly ease of the insulating film can be evaluated by inserting the insulating film into each hole in an assembly jig such as the one shown in FIG. 3 , inserting a copper wire bundle, compressing the copper wire bundle to a predetermined height, removing the copper wire bundle and the test piece from the assembly jig, and observing the condition of the test piece. If no tearing, dents, or other deformation occurs, the assembly ease can be evaluated as good.

[0027] (Resin Layer) The present insulating film includes a resin layer. The resin layer contains a resin as a main component. In this specification, "main component" means that the resin is contained in an amount of 50% by mass or more relative to the total mass of the resin layer. The resin content relative to the total mass of the resin layer is preferably 60% by mass or more, more preferably 70% by mass or more, even more preferably 80% by mass or more, and particularly preferably 90% by mass or more.

[0028] The resin contained in the resin layer may be either a thermoplastic resin or a thermosetting resin, but from the viewpoint of adhesion to the aramid paper, the resin is preferably a thermoplastic resin.

[0029] The glass transition temperature of the resin is preferably 50° C. or higher, more preferably 90° C. or higher, and even more preferably 140° C. or higher. The glass transition temperature of the resin is preferably 300° C. or lower, more preferably 280° C. or lower, and even more preferably 260° C. or lower. By setting the glass transition temperature of the resin within the above range, the insulating properties and assemblability of the insulating film can be more effectively improved.

[0030] The resin may be a crystalline resin or an amorphous resin. In the case of a crystalline resin, the crystalline melting temperature (melting point) is preferably 150°C or higher, more preferably 200°C or higher, and even more preferably 250°C or higher. The crystalline melting temperature (melting point) is preferably 500°C or lower, more preferably 400°C or lower, and even more preferably 350°C or lower. By setting the crystalline melting temperature (melting point) of the resin within the above range, the insulating properties and assemblability of the insulating film can be more effectively improved.

[0031] The tensile modulus of the resin is preferably 1.0 GPa or more, more preferably 1.5 GPa or more, and even more preferably 2.0 GPa or more. The tensile modulus of the resin is preferably 20.0 GPa or less, more preferably 15.0 GPa or less, and even more preferably 10.0 GPa or less. By setting the tensile modulus of the resin within the above range, the insulating properties and assembly properties of the insulating film can be more effectively improved. The tensile modulus of the resin is a value obtained by measuring a sample obtained by injection molding resin pellets at a temperature of 23°C in accordance with ISO 527.

[0032] Examples of the resin include thermoplastic resins and thermosetting resins. Examples of the thermoplastic resin include at least one selected from the group consisting of polyetherimide, polyaryletherketone, polyimide, polyphenylene ether, polyetherimide sulfone, polyphenylene sulfide, polyarylate, polysulfone, polyethersulfone, polyamideimide, polystyrene, aromatic polyamide, aromatic polyester, and polycarbonate. Among them, the thermoplastic resin is preferably at least one selected from the group consisting of polyetherimide, polyaryletherketone, polyimide, polyphenylene sulfide, and aromatic polyester, more preferably at least one selected from the group consisting of polyetherimide, polyetheretherketone, polyimide, polyphenylene sulfide, polyethylene naphthalate, and polyethylene terephthalate, and even more preferably at least one selected from the group consisting of polyetherimide, polyethylene naphthalate, and polyethylene terephthalate. The thermoplastic resin is preferably a thermoplastic resin having an aromatic ring, and using such a resin makes it easier to control the density of the resin layer within the desired range. The thermosetting resin may be, for example, at least one selected from the group consisting of epoxy resin, polyurethane, polyolefin, silicone resin, polyimide, polyphenol, and acrylic resin.

[0033] The thickness of the resin layer is preferably 30 μm or more, more preferably 32 μm or more, preferably 34 μm or more, preferably 36 μm or more, more preferably 38 μm or more, and even more preferably 40 μm or more. The thickness of the resin layer is preferably 80 μm or less, more preferably 70 μm or less, and even more preferably 60 μm or less. The resin layer may have a single-layer structure or a multilayer structure. In the case of a multilayer structure, the total thickness of each layer is preferably within the above range. In this embodiment, by setting the thickness of the resin layer to the above lower limit or more, the insulating properties of the insulating film can be more effectively improved. Furthermore, by setting the thickness of the insulating film to the above lower limit or more, the strength of the insulating film can be increased, improving assembly. On the other hand, by setting the thickness of the resin layer to the above upper limit or less, the insulating film can be made thinner, which results in an increased space factor for the coil in the motor and thereby improving motor efficiency. Furthermore, by setting the thickness of the resin layer to the above upper limit or less, the thermal conductivity (heat transmission) of the insulating film can be more effectively improved.

[0034] The density of the resin layer is 1.0 g / cm ３ It is preferable that the density is 1.05 g / cm or more. ３ More preferably, it is 1.1 g / cm or more. ３ More preferably, it is 1.15 g / cm or more. ３ More preferably, it is 1.2 g / cm or more. ３ On the other hand, there is no particular upper limit, but it is particularly preferable that the density is 2.0 g / cm ３ In the case of a resin layer containing a filler, the density is preferably 3.0 g / cm or less. ３ It is preferable that:

[0035] <Polyetherimide> Polyetherimide (hereinafter sometimes referred to as "PEI") is an amorphous resin having imide groups. There are no particular limitations on the polyetherimide, and its production method and properties are described in, for example, U.S. Patents 3,905,942 and 3,803,085.

[0036] Specifically, the PEI preferably has a repeating unit represented by the following structural formula (1): Whether the polyetherimide resin is amorphous can be determined by DSC.

[0037]

[0038] In formula (1), Y １ ~Y ６ each independently represents a hydrogen atom, an alkyl group, or an alkoxy group; Ar ７ ~Ar ９ each independently represents an arylene group having 6 to 24 carbon atoms which may have a substituent; X １ is a single bond, or -O-, -SO ２ It represents either -, -S-, -C(=O)-, or a divalent aliphatic hydrocarbon group.

[0039] The polyetherimide preferably has a structure in which the repeating unit represented by the above formula (1) is repeated, for example, 10 to 1000 times, and the number of repeating units (n) is more preferably 20 to 700, and even more preferably 30 to 500. If the number of repeating units is within the above range, the viscosity when melted is not too high, and the moldability is excellent, and various properties such as heat resistance and heat aging resistance tend to be well-balanced and favorable.

[0040] Y １ ~Y ６The alkyl group in the formula (I) is, for example, an alkyl group having 1 to 20 carbon atoms, preferably 1 to 10 carbon atoms, more preferably 1 to 6 carbon atoms, and even more preferably 1 to 2 carbon atoms. Specific preferred examples include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, an n-pentyl group, an isopentyl group, a neopentyl group, a 1-methylpentyl group, an n-hexyl group, and an isohexyl group. １ ~Y ６ The alkoxy group in the formula (I) is, for example, an alkoxy group having 1 to 20 carbon atoms, preferably 1 to 10 carbon atoms, more preferably 1 to 6 carbon atoms, and even more preferably 1 to 2 carbon atoms, and specifically preferred are a methoxy group, an ethoxy group, an n-propoxy group, an isopropoxy group, an n-butoxy group, a sec-butoxy group, a tert-butoxy group, an n-pentyloxy group, an n-hexyloxy group, and the like. １ ~Y ６ may be the same or different. １ ~Y ６ At least one of Y is preferably a hydrogen atom; １ ~Y ６ It is more preferable that all of are hydrogen atoms.

[0041] Ar ７ ~Ar ９ In the above, examples of the arylene group include a phenylene group, a naphthylene group, and an anthracenylene group. Examples of the substituent of the arylene group include an alkyl group, a halogen, an alkoxy group, and a halogen-substituted alkyl group. The alkyl group and alkoxy group as the substituent have, for example, 1 to 6 carbon atoms, preferably 1 to 2 carbon atoms, and specific examples thereof are as described above. The halogen-substituted alkyl group is a group in which one or more hydrogen atoms of the alkyl group are substituted with halogen. The alkyl group in the halogen-substituted alkyl group is the same as described above. Examples of the halogen include a chlorine atom, a bromine atom, a fluorine atom, and an iodine atom. Ar ７ ~Ar ９may be the same as or different from each other. ７ ~Ar ９ When Ar has a substituent, the arylene group preferably has 6 to 24 carbon atoms. ７ ~Ar ９ is preferably a phenylene group which may have a substituent, and among these, a phenylene group is preferred.

[0042] X １ The divalent aliphatic hydrocarbon group in the formula (I) is preferably a divalent aliphatic hydrocarbon group having 1 to 6 carbon atoms, and more preferably a divalent saturated aliphatic hydrocarbon group having 1 to 6 carbon atoms. ｙ H ２ｙ - (y is an integer of 1 to 6), and specifically includes a methylene group, a dimethylene group, a trimethylene group, a propylene group, an ethylidene group (-CH(CH ３ )-), dimethylmethylene group (-C(CH ３ ) ２ -) and the like. １ is preferably a divalent saturated aliphatic hydrocarbon group, and particularly preferably a dimethylmethylene group (-C(CH ３ ) ２ It is more preferable that the formula is -.

[0043] In the above formula (1), Ar ９ may be a 1,4- or 1,3-arylene group having 6 to 24 carbon atoms, which may have a substituent, but is preferably a 1,4-arylene group having 6 to 24 carbon atoms, which may have a substituent. When the bonding positions with the imide group are the 1 and 4 positions, the structure is stable and heat aging resistance is improved, and excellent low water absorption, heat resistance, and impact resistance such as puncture impact strength tend to be easily achieved. Therefore, it is preferable that the polyetherimide has a repeating unit represented by the following structural formula (2):

[0044]

[0045] In formula (2), Y １ ~Y ６ each independently represents a hydrogen atom, an alkyl group, or an alkoxy group; Ar ７ ~Ar９ each independently represents an arylene group having 6 to 24 carbon atoms which may have a substituent; X １ is a single bond, or -O-, -SO ２ (1,4)Ar in formula (2) represents either -, -S-, -C(=O)-, or a divalent aliphatic hydrocarbon group. ９ is an imide group ９ This indicates that the bond is made to the 1st and 4th positions of the group.

[0046] Y in formula (2) １ ~Y ６ , X １ is as explained above. ９ Examples of the arylene group in Ar include a 1,4-phenylene group, a 1,4-naphthylene group, and a 1,4-anthracenylene group. These arylene groups may have a substituent as described above, and the substituent is as described above. ９ is preferably a 1,4-phenylene group which may have a substituent, and more preferably a 1,4-phenylene group.

[0047] In formula (2), Ar ７ , Ar ８ is as explained above, but Ar ７ and Ar ８ is preferably a 1,4-arylene group having 6 to 24 carbon atoms which may have a substituent, and examples of the 1,4-arylene group include a 1,4-phenylene group, a 1,4-naphthylene group, and a 1,4-anthracenylene group. These arylene groups may have a substituent as described above, and the substituent is as described above. ７ and Ar ８ is more preferably a 1,4-phenylene group which may have a substituent, and even more preferably a 1,4-phenylene group.

[0048] In particular, it is particularly preferable that the polyetherimide used in the resin layer has a repeating unit represented by the following structural formula (3). When the polyetherimide has the following structure, the insulating film tends to have excellent mechanical properties, excellent crystallinity, heat resistance, and good adhesion to aramid paper. Furthermore, it tends to have good moldability and secondary processability.

[0049]

[0050] In formula (3), the number of repeating units (n) is preferably 10 to 1000, more preferably 20 to 700, and even more preferably 30 to 500. When the number of repeating units (n) is within the above range, the viscosity when melted is not too high, and moldability is excellent, and the balance of various properties such as heat resistance and heat aging resistance tends to be excellent.

[0051] More specifically, it is particularly preferable that the polyetherimide has a repeating unit represented by the following structural formula (4) or (5): In formulas (4) and (5), the number of repeating units (n) is preferably 10 to 1000, more preferably 20 to 700, and even more preferably 30 to 500. When the number of repeating units (n) is within the above range, the viscosity when melted is not too high, and the moldability is excellent, and the balance of various properties such as heat resistance and heat aging resistance tends to be excellent.

[0052] The polyetherimide resin having the structure represented by the structural formula (4) is a polycondensate (meta-polyetherimide) of 4,4'-[isopropylidenebis(p-phenyleneoxy)]diphthalic dianhydride and m-phenylenediamine, and the polyetherimide resin having the structure represented by the structural formula (5) is a polycondensate (para-polyetherimide) of 4,4'-[isopropylidenebis(p-phenyleneoxy)]diphthalic dianhydride and p-phenylenediamine.

[0053] The glass transition temperature of PEI is preferably 160°C or higher, more preferably 170°C or higher, even more preferably 180°C or higher, even more preferably 190°C or higher, and particularly preferably 200°C or higher. The glass transition temperature of PEI is preferably 300°C or lower, more preferably 290°C or lower, even more preferably 280°C or lower, even more preferably 270°C or lower, and particularly preferably 260°C or lower. If the glass transition temperature is equal to or higher than the lower limit, a resin film having sufficient heat resistance is easily obtained. If the glass transition temperature is equal to or lower than the upper limit, molding processability at low temperatures is easily achieved.

[0054] As PEI, for example, products commercially available from Sabic Innovative Plastics under the trade name "Ultem" series can be used.

[0055] <Polyimide> Polyimide is a resin containing an imide bond in a repeating unit obtained by polymerizing a tetracarboxylic acid component and a diamine component. Among polyimides, thermoplastic polyimide will be described below.

[0056] The thermoplastic polyimide preferably has a repeating unit derived from the tetracarboxylic acid component (a-1) and a repeating unit derived from the aliphatic diamine component (a-2).

[0057] Examples of the tetracarboxylic acid component (a-1) constituting the thermoplastic polyimide include alicyclic tetracarboxylic acids such as cyclobutane-1,2,3,4-tetracarboxylic acid, cyclopentane-1,2,3,4-tetracarboxylic acid, and cyclohexane-1,2,4,5-tetracarboxylic acid, 3,3',4,4'-diphenylsulfonetetracarboxylic acid, 3,3',4,4'-benzophenonetetracarboxylic acid, biphenyltetracarboxylic acid, naphthalene-1,4,5,8-tetracarboxylic acid, and pyromellitic acid. In addition, alkyl esters of these compounds can be used in the polymerization of the thermoplastic polyimide.

[0058] In particular, it is preferable that more than 50 mol% of the tetracarboxylic acid component (a-1) is pyromellitic acid. When the tetracarboxylic acid component (a-1) is mainly composed of pyromellitic acid, the resin film tends to exhibit excellent heat resistance and secondary processability. The content of pyromellitic acid in the tetracarboxylic acid component (a-1) is more preferably 60 mol% or more, even more preferably 80 mol% or more, and particularly preferably 90 mol% or more, and it is particularly preferable that all (100 mol%) of the tetracarboxylic acid component (a-1) is pyromellitic acid.

[0059] The diamine component constituting the thermoplastic polyimide preferably comprises aliphatic diamine (a-2) as the main component. That is, it is preferable that more than 50 mol% of the diamine component is aliphatic diamine (a-2), more preferably 60 mol% or more, even more preferably 80 mol% or more, and particularly preferably 90 mol% or more, and it is particularly preferable that all (100 mol%) of the diamine component is aliphatic diamine (a-2). This makes it easier for the resin film to exhibit excellent heat resistance and secondary processability. In this specification, aliphatic diamines also include alicyclic diamines.

[0060] The aliphatic diamine (a-2) is not particularly limited as long as it is a diamine component having amino groups at both ends of a hydrocarbon group, and examples thereof include alicyclic diamines, linear aliphatic diamines, and branched aliphatic diamines. When heat resistance, heat aging resistance, and the like are important, the aliphatic diamine (a-2) preferably contains an alicyclic diamine. The alicyclic diamine may have amino groups bonded to both ends of a cyclic hydrocarbon (i.e., carbon atoms that constitute a ring and are not adjacent to each other), or may have amino groups bonded to a carbon atom of the cyclic hydrocarbon and to the end of a hydrocarbon bonded to the cyclic hydrocarbon, or may have amino groups bonded to the ends of each of the two hydrocarbons bonded to the cyclic hydrocarbon. Specific examples of alicyclic diamines include 1,3-bis(aminomethyl)cyclohexane, 1,4-bis(aminomethyl)cyclohexane, 4,4'-diaminodicyclohexylmethane, 4,4'-methylenebis(2-methylcyclohexylamine), isophoronediamine, norbornanediamine, bis(aminomethyl)tricyclodecane, etc. Among these, 1,3-bis(aminomethyl)cyclohexane is preferably used from the viewpoints of heat resistance, heat aging resistance, moldability, secondary processability, etc.

[0061] On the other hand, when toughness, moldability, and secondary processability are important, it is preferable that the aliphatic diamine (a-2) contains at least one of a linear aliphatic diamine and a branched aliphatic diamine. The linear aliphatic diamine and the branched aliphatic diamine preferably have amino groups at both ends of the linear hydrocarbon and at both ends of the branched hydrocarbon. The linear aliphatic diamine is not particularly limited as long as it is a diamine component having amine groups at both ends of an alkyl group, and specific examples include ethylenediamine (carbon number 2), propylenediamine (carbon number 3), butanediamine (carbon number 4), pentanediamine (carbon number 5), hexanediamine (carbon number 6), heptanediamine (carbon number 7), octanediamine (carbon number 8), nonanediamine (carbon number 9), decanediamine (carbon number 10), undecanediamine (carbon number 11), and dodecanediamine (carbon number 12). Examples of such linear aliphatic diamines include tridecanediamine (13 carbon atoms), tetradecanediamine (14 carbon atoms), pentadecanediamine (15 carbon atoms), hexadecanediamine (16 carbon atoms), heptadecanediamine (17 carbon atoms), octadecanediamine (18 carbon atoms), nonadecanediamine (19 carbon atoms), eicosanediamine (20 carbon atoms), triacontanediamine (30 carbon atoms), tetracontanediamine (40 carbon atoms), and pentacontanediamine (50 carbon atoms). Among these, from the viewpoints of excellent moldability, secondary processability, and low moisture absorption, linear aliphatic diamines having 4 to 20 carbon atoms are preferred, linear aliphatic diamines having 5 to 16 carbon atoms are more preferred, and linear aliphatic diamines having 6 to 12 carbon atoms are even more preferred. Examples of the branched aliphatic diamine include those obtained by bonding a branched structure having preferably 1 to 20 carbon atoms, more preferably 1 to 10 carbon atoms, to these linear aliphatic diamines. From the viewpoint of crystallinity, it is particularly preferable that the aliphatic diamine (a-2) contains a linear aliphatic diamine.

[0062] The thermoplastic polyimide may contain a structural unit derived from a diamine component other than the aliphatic diamine (a-2). Specific examples of the other diamine component include 1,4-phenylenediamine, 1,3-phenylenediamine, 2,4-toluenediamine, 4,4'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 4,4'-diaminodiphenylmethane, 1,4-bis(4-aminophenoxy)benzene, 1,3-bis(4-aminophenoxy)benzene, 1,3-bis(3-aminophenoxy)benzene, α,α'-bis(4-aminophenyl)1,4'-diisopropylbenzene, α,α'-bis(3-aminophenyl)-1,4-diisopropylbenzene, 2,2-bis[4-(4-aminophenoxy)phenyl]propane, 4,4'-diaminodiphenylmethane, 1,4-bis(4-aminophenoxy)benzene, 1,3-bis(4-aminophenoxy)benzene, α,α'-bis(4-aminophenyl)-1,4 ...1,3-bis(4-aminophenoxy)benzene, α,α'-bis(4-aminophenyl Examples of the diamine component include aromatic diamine components such as aminodiphenyl sulfone, bis[4-(4-aminophenoxy)phenyl]sulfone, bis[4-(3-aminophenoxy)phenyl]sulfone, 2,6-diaminonaphthalene, 1,5-diaminonaphthalene, p-xylylenediamine, and m-xylylenediamine; ether diamine components such as polyethylene glycol bis(3-aminopropyl)ether and polypropylene glycol bis(3-aminopropyl)ether; and siloxane diamines.

[0063] The aliphatic diamine (a-2) may contain at least one of a linear aliphatic diamine and a branched aliphatic diamine, or an alicyclic diamine, or both. However, from the viewpoint of achieving a good balance of various performances, it preferably contains at least one of a linear aliphatic diamine and a branched aliphatic diamine and an alicyclic diamine, and more preferably contains both a linear aliphatic diamine and an alicyclic diamine. When both a linear aliphatic diamine and at least one of a branched aliphatic diamine and an alicyclic diamine are contained, the content ratio thereof is preferably, on a molar basis, 1:99 to 90:10 (at least one of a linear aliphatic diamine and a branched aliphatic diamine:alicyclic diamine), more preferably 1:99 to 80:20, even more preferably 1:99 to 70:30, particularly preferably 10:90 to 70:30, particularly preferably 20:80 to 70:30, and most preferably 25:75 to 60:40. If the ratio of at least one of a linear aliphatic diamine and a branched aliphatic diamine contained in the aliphatic diamine (a-2) to the alicyclic diamine is within this range, the balance of heat resistance, heat aging resistance, toughness, moldability, etc. will be excellent.

[0064] The thermoplastic polyimide may be crystalline. A crystalline thermoplastic polyimide exhibits a crystalline melting peak in differential scanning calorimetry (DSC) measurements. The specific crystalline melting temperature of the thermoplastic polyimide is preferably 260 to 350°C, more preferably 270 to 345°C, and even more preferably 280 to 340°C. If the crystalline melting temperature of the thermoplastic polyimide is equal to or higher than the lower limit, the laminated film tends to have sufficient heat resistance. On the other hand, if the crystalline melting temperature is equal to or lower than the upper limit, molding or secondary processing can be easily performed at a relatively low temperature, which is preferable.

[0065] The glass transition temperature of the thermoplastic polyimide is preferably 150°C or higher, more preferably 160°C or higher, even more preferably 170°C or higher, even more preferably 175°C or higher, and particularly preferably 180°C or higher. The glass transition temperature of the thermoplastic polyimide is preferably 300°C or lower, more preferably 280°C or lower, even more preferably 260°C or lower, even more preferably 250°C or lower, and particularly preferably 240°C or lower. If the glass transition temperature of the thermoplastic polyimide is equal to or higher than the lower limit, the resin film tends to have sufficient heat resistance. On the other hand, if the glass transition temperature is equal to or lower than the upper limit, molding at a relatively low temperature is easy, which is preferable.

[0066] Polyimides other than thermoplastic polyimides also include aromatic polyimides in which aromatic compounds are directly linked by imide bonds. Examples of tetracarboxylic acid components constituting aromatic polyimides include pyromellitic dianhydride and 3,3',4,4'-biphenyltetracarboxylic dianhydride. Examples of diamine components constituting aromatic polyimides include p-phenylenediamine and 4,4'-diaminodiphenyl ether. Commercially available polyimides such as "Kapton" (manufactured by DuPont-Toray Co., Ltd.) and "Upilex" (manufactured by Ube Industries, Ltd.) can also be used.

[0067] <Aromatic Polyamide> The aromatic polyamide (hereinafter sometimes referred to as "aromatic PA") may be a wholly aromatic polyamide obtained by polymerizing an aromatic dicarboxylic acid and an aromatic diamine, or a polyamide resin (semi-aromatic polyamide) obtained by polymerizing a linear aliphatic dicarboxylic acid component or a linear aliphatic diamine component having 10 to 12 carbon atoms and a diamine component or dicarboxylic acid component having an aromatic ring as the main components. Among these, it is preferable to use a semi-aromatic polyamide that exhibits thermoplasticity that provides good thermal fusion bonding with aramid paper. Among these, the aromatic polyamide is more preferably a polyamide resin (semi-aromatic polyamide) obtained by polymerizing a linear aliphatic dicarboxylic acid component or a linear aliphatic diamine component having 10 to 12 carbon atoms and a diamine component or dicarboxylic acid component having an aromatic ring as the main components.

[0068] The content of linear aliphatic dicarboxylic acid units constituting the semi-aromatic polyamide is 60 mol% or more, preferably 80 mol% or more, more preferably 90 mol% or more, and even more preferably 100 mol% of all dicarboxylic acid units. All of the dicarboxylic acid components may be one or more selected from the group consisting of 1,8-octanedicarboxylic acid, 1,9-nonanedicarboxylic acid, and 1,10-decanedicarboxylic acid. By using a linear aliphatic dicarboxylic acid having from 10 to 12 carbon atoms, it becomes easier to obtain a semi-aromatic polyamide that is excellent in both low water absorbency and heat resistance.

[0069] The content of linear aliphatic diamine units constituting the semi-aromatic polyamide is 60 mol% or more, preferably 80 mol% or more, more preferably 90 mol% or more, and even more preferably 100 mol% of all diamine units. All of the diamine components may be one or more selected from the group consisting of 1,10-decanediamine, 1,11-undecanediamine, and 1,12-dodecanediamine. By using a linear aliphatic diamine having 10 to 12 carbon atoms, it becomes easier to obtain a semi-aromatic polyamide that is excellent in both low water absorbency and heat resistance.

[0070] The content of aromatic dicarboxylic acid units constituting the semi-aromatic polyamide is 60 mol% or more, preferably 80 mol% or more, more preferably 90 mol% or more, and even more preferably 100 mol% based on the total dicarboxylic acid units. All of the dicarboxylic acid components may be terephthalic acid and / or isophthalic acid. By using terephthalic acid and / or isophthalic acid as the aromatic dicarboxylic acid, it becomes easier to obtain a semi-aromatic polyamide having both low water absorption and excellent heat resistance.

[0071] The content of aromatic diamine units constituting the semi-aromatic polyamide is 60 mol% or more, preferably 80 mol% or more, more preferably 90 mol% or more, and even more preferably 100 mol% of all diamine units. All of the diamine components may be paraxylylenediamine and / or metaxylylenediamine. By using paraxylylenediamine and / or metaxylylenediamine as the aromatic diamine, it becomes easier to obtain a semi-aromatic polyamide that is excellent in both low water absorption and heat resistance.

[0072] Specific examples of aromatic polyamides include polyamide 4T (PA4T; manufactured by DSM Engineering Plastics, etc.), polyamide 6T (PA6T; manufactured by Mitsui Chemicals, etc.), polyamide MXD6 (PAMXD6; manufactured by Mitsubishi Gas Chemical, etc.), polyamide 9T (PA9T; manufactured by Kuraray, etc.), polyamide 10T (PA10T; manufactured by Unitika, Daicel-Evonik, etc.), polyamide 11T (PA11T; manufactured by Toyobo, etc.), polyamide 12T (PA12T; manufactured by Henan Junheng, etc.), and polyamide 13T (PA13T).

[0073] The glass transition temperature Tg of the aromatic polyamide is preferably 100° C. or higher, more preferably 110° C. or higher, and even more preferably 120° C. or higher. The glass transition temperature Tg of the aromatic polyamide is preferably 200° C. or lower, more preferably 180° C. or lower, and even more preferably 160° C. or lower.

[0074] The melting point (crystalline melting temperature) Tm of the aromatic polyamide is preferably 260° C. or higher, more preferably 280° C. or higher, and even more preferably 300° C. or higher. The melting point (crystalline melting temperature) Tm of the aromatic polyamide is preferably 350° C. or lower, more preferably 340° C. or lower, and even more preferably 330° C. or lower. If the melting point of the aromatic polyamide is within the above range, heat resistance can be improved while moldability (fluidity) can be ensured, and decomposition does not occur during molding, ensuring safety during production.

[0075] <Aromatic Polyester> The aromatic polyester refers to a polyester resin having an aromatic group in at least one of the polycarboxylic acid unit and the polyhydric alcohol unit constituting the polyester. The aromatic polyester may be a homopolyester or a copolymer polyester.

[0076] The homopolyester is preferably one obtained by polycondensation of an aromatic dicarboxylic acid and an aliphatic glycol. Examples of aromatic dicarboxylic acids include terephthalic acid and 2,6-naphthalenedicarboxylic acid, and examples of aliphatic glycols include ethylene glycol, diethylene glycol, 1,4-butanediol, and 1,4-cyclohexanedimethanol. Representative examples of homopolyesters include polyethylene terephthalate (PET), polybutylene terephthalate (PBT), and polyethylene naphthalate (PEN). In this embodiment, it is preferable to use at least one selected from polyethylene naphthalate and polyethylene terephthalate, which have excellent durability.

[0077] On the other hand, examples of the dicarboxylic acid component of the copolymer polyester include one or more of isophthalic acid, phthalic acid, terephthalic acid, 2,6-naphthalenedicarboxylic acid, adipic acid, sebacic acid, etc., and examples of the glycol component include one or more of ethylene glycol, diethylene glycol, propylene glycol, butanediol, 4-cyclohexanedimethanol, neopentyl glycol, etc. The copolymer polyester contains an aromatic compound in the dicarboxylic acid component and / or the glycol component.

[0078] When the aromatic polyester is a copolymer polyester, it is preferably a copolymer containing 30 mol% or less of a third component, more preferably 60 mol% or more, and preferably 80 mol% or more of ethylene terephthalate units or ethylene-2,6-naphthalate units, and from the viewpoint of versatility, it is even more preferably 60 mol% or more, and preferably 80 mol% or more of ethylene terephthalate units.

[0079] The polyester polymerization catalyst is not particularly limited, and a conventionally known compound can be used, for example, a titanium compound, a germanium compound, an antimony compound, a manganese compound, an aluminum compound, a magnesium compound, a calcium compound, etc. Among these, at least one of a titanium compound and an antimony compound is preferred.

[0080] In order to suppress the amount of precipitation of oligomer components, the film may be produced using a polyester having a low content of oligomer components as the raw material. As a method for producing a polyester having a low content of oligomer components, various known methods can be used, such as a method in which solid-state polymerization is carried out after the polyester is produced.

[0081] <Polycarbonate> Polycarbonate (hereinafter sometimes referred to as "PC") is obtained by polymerizing bisphenols with phosgene or diphenyl carbonate. Widely used inexpensive polymerization methods include the interfacial method (interfacial polycondensation method), in which bisphenols and phosgene are reacted in solution, and the solution method, in which bisphenols and carbonate diesters are polycondensed via transesterification. The following compounds are suitable for use as bisphenols. Polycarbonates can be made not only from homopolymers of one type of bisphenol, but also from copolymers produced by copolymerizing two or more types of bisphenols.

[0082]

[0083] Of the above, polycarbonates having a structural unit represented by the following formula (6) are preferred.

[0084]

[0085] In formula (6), substituent R １ and R ２ each independently represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, and the substituents may be bonded to form a ring. ３ and R ４ each independently represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, and j and k represent 0 to 4. W represents a single bond, an oxygen atom, or -CR ５ R ６ -, and the substituent R ５ and R ６ are each independently a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or a phenyl group, provided that the units t and u have different structures.

[0086] The number of carbon atoms in the alkyl group is preferably 6 or less, more preferably 4 or less, and particularly preferably 3 or less. Specific examples of the alkyl group include linear alkyl groups such as methyl, ethyl, and propyl groups; branched alkyl groups such as isopropyl, tert-butyl, and isobutyl groups; and cyclic alkyl groups such as cyclohexyl and cyclopentyl groups. Among these, a methyl group is particularly preferred from the viewpoint of synthesis. Furthermore, the substituents may be bonded to each other to form a ring.

[0087] The number of carbon atoms in the aryl group is preferably 30 or less, more preferably 20 or less, and particularly preferably 15 or less. Specific examples include a phenyl group, a naphthyl group, an anthranyl group, and a pyrenyl group.

[0088] Specific examples of suitable structural units of polycarbonate are shown below, but polycarbonate is not limited to these.

[0089]

[0090] The viscosity average molecular weight of the polycarbonate is preferably 10,000 or more, more preferably 20,000 or more. The viscosity average molecular weight of the polycarbonate is preferably 150,000 or less, more preferably 120,000 or less, and even more preferably 100,000 or less. By setting the viscosity average molecular weight within the above range, a resin film having sufficient heat resistance can be easily obtained.

[0091] <Polyaryletherketone> Polyaryletherketone (hereinafter sometimes referred to as "PAEK") is a crystalline resin containing an arylene group, an ether group, and a carbonyl group. Specific examples include a polyetheretherketone (PEEK) resin represented by structural formula (7), a polyetherketone (PEK) resin represented by structural formula (8), a polyetherketoneketone (PEKK) resin represented by structural formula (9), a polyetheretherketoneketone (PEEKK) resin represented by structural formula (10), and a polyetherketoneetherketoneketone (PEKEKK) resin represented by structural formula (11).

[0092]

[0093]

[0094]

[0095]

[0096]

[0097] Among the above polyaryletherketones, polyetheretherketone (PEEK) and polyetherketone (PEK) are preferred from the viewpoints of availability, production cost, and moldability, with polyetheretherketone (PEEK) being particularly preferred. Polyaryletherketones may be used singly or in combination of two or more. Furthermore, polyaryletherketones may be copolymers having two or more of the chemical structures shown in (7) to (11) above.

[0098] The glass transition temperature Tg of the polyaryl ether ketone is preferably 100° C. or higher, more preferably 120° C. or higher, and even more preferably 140° C. or higher. The glass transition temperature Tg of the polyaryl ether ketone is preferably 200° C. or lower, more preferably 190° C. or lower, and even more preferably 180° C. or lower.

[0099] The melting point (crystalline melting temperature) Tm of the polyaryl ether ketone is preferably 300° C. or higher, more preferably 310° C. or higher, and even more preferably 320° C. or higher. The melting point (crystalline melting temperature) Tm of the polyaryl ether ketone is preferably 400° C. or lower, more preferably 380° C. or lower, and even more preferably 360° C. or lower. If the melting point of the polyaryl ether ketone is within the above range, heat resistance can be improved while moldability (fluidity) can be ensured, and decomposition does not occur during molding, ensuring safety during production.

[0100] <Polyphenylene sulfide> Polyphenylene sulfide (hereinafter sometimes referred to as "PPS") is a polymer having a skeleton in which benzene rings and sulfur atoms are alternately bonded. Examples of polyphenylene sulfide include resins having a structural unit represented by the following formula. Polyphenylene sulfide may have a linear structure or may be crosslinked. -(Ph-S)-

[0101] In the formula, Ph is a phenylene group, and examples of the phenylene group include p-phenylene, m-phenylene, o-phenylene, alkyl-substituted phenylene, phenyl-substituted phenylene, halogen-substituted phenylene, amino-substituted phenylene, amido-substituted phenylene, p,p'-diphenylene sulfone, p,p'-biphenylene, p,p'-biphenylene ether, etc. Of these, p-phenylene is preferred.

[0102] The crystalline melting temperature (Tm) of polyphenylene sulfide is preferably 270°C or higher, more preferably 271°C or higher, even more preferably 272°C or higher, and particularly preferably 273°C or higher. If the crystalline melting temperature of polyphenylene sulfide is above the above lower limit, the resin layer tends to have excellent heat resistance. Furthermore, the crystalline melting temperature of polyphenylene sulfide is preferably 300°C or lower, more preferably 299°C or lower, even more preferably 297°C or lower, particularly preferably 295°C or lower, and most preferably 290°C or lower. If the crystalline melting temperature of polyphenylene sulfide is below the above upper limit, it is possible to improve moldability (fluidity) while also improving heat resistance.

[0103] The heat of crystalline fusion (ΔHm) of polyphenylene sulfide is preferably 35 J / g or more, more preferably 36 J / g or more, even more preferably 37 J / g or more, and particularly preferably 38 J / g or more. If the heat of crystalline fusion of polyphenylene sulfide is above the above lower limit, the resin layer tends to have sufficient crystallinity and excellent heat resistance and rigidity. Furthermore, the heat of crystalline fusion of polyphenylene sulfide is preferably 55 J / g or less, more preferably 52 J / g or less, and even more preferably 50 J / g or less. If the heat of crystalline fusion of polyphenylene sulfide is below the above upper limit, the crystallinity is not too high, so the moldability (fluidity) tends to be excellent, and the resulting resin layer tends to have excellent durability and impact resistance. Note that when there are multiple crystalline fusion peaks, the sum of their heats is calculated as ΔHm.

[0104] The crystallization temperature (Tc) of polyphenylene sulfide during the cooling process is preferably 200 ° C. or higher, more preferably 202 ° C. or higher, even more preferably 204 ° C. or higher, particularly preferably 206 ° C. or higher, and most preferably 208 ° C. or higher. If the crystallization temperature of polyphenylene sulfide during the cooling process is above the above lower limit, the crystallization rate is high and the productivity of the resin layer tends to be excellent. For example, when producing a film, by setting the temperature of the cast roll to a temperature above the glass transition temperature and below the crystalline melting temperature, crystallization is promoted while the resin is in contact with the cast roll, and a crystallized film is obtained. However, if the crystallization temperature during the cooling process is above the above lower limit, the crystallization rate is high and crystallization can be completed by the cast roll, resulting in a high elastic modulus. As a result, sticking to the roll is suppressed, and the appearance of the film tends to be improved.

[0105] The crystallization temperature (Tc) of polyphenylene sulfide during the temperature drop process is preferably 255° C. or lower, more preferably 253° C. or lower, even more preferably 251° C. or lower, and particularly preferably 250° C. or lower. If the crystallization temperature during the temperature drop process is equal to or lower than the above upper limit, crystallization is not too fast, which reduces uneven cooling during molding and tends to result in a uniformly crystallized, high-quality resin layer.

[0106] <Optional Components> The resin layer may contain various additives such as inorganic fillers, organic fillers, heat stabilizers, antioxidants, ultraviolet absorbers, light stabilizers, antibacterial and antifungal agents, antistatic agents, lubricants, pigments, and dyes, as long as the effects of the present invention are not impaired.

[0107] (Aramid Paper) The insulating film includes aramid paper on both sides of the resin layer. The aramid paper is preferably a sheet-like material made by papermaking aramid short fibers.

[0108] Aramid is a linear polymeric compound in which 60% or more of the amide bonds are directly bonded to aromatic rings. Examples of aramid include polymetaphenylene isophthalamide and its copolymers, polyparaphenylene terephthalamide and its copolymers, and copolyparaphenylene-3,4'-diphenyl ether terephthalamide.

[0109] Of the aramid papers disposed on both sides of the resin layer, the thickness of at least one of the aramid papers is preferably 49 μm or less, more preferably 47 μm or less, even more preferably 45 μm or less, even more preferably 42 μm or less, and particularly preferably 40 μm or less. The thickness of at least one of the aramid papers is preferably 1 μm or more, more preferably 5 μm or more, and even more preferably 10 μm or more. In this embodiment, by setting the thickness of at least one of the aramid papers to the above upper limit or less, a thinner insulating film can be achieved, thereby increasing the coil space factor within the motor and improving motor efficiency. Furthermore, by setting the thickness of at least one of the aramid papers to the above upper limit or less, the thermal conductivity (heat transmission) of the insulating film can be more effectively improved. On the other hand, by setting the thickness of the aramid paper to the above lower limit or more, the strength of the insulating film can be increased, improving assembly ease. In this embodiment, it is preferable that the thickness of both pieces of aramid paper disposed on both sides of the resin layer be within the above range.

[0110] The basis weight of the aramid paper is 10 g / m ２ It is preferable that the content is 15 g / m or more. ２ More preferably, it is 20 g / m or more. ２ The basis weight of the aramid paper is more preferably 1000 g / m or more. ２ Preferably, it is 900 g / m or less. ２ More preferably, it is 800 g / m or less. ２ It is even more preferable that:

[0111] The density of aramid paper is 0.5 g / cm ３ It is preferable that the density is 0.55 g / cm or more, and more preferably 0.55 g / cm ３ Above, 0.6g / cm ３ Above, 0.65g / cm ３ Above, 0.7g / cm ３ Above, 0.75g / cm ３ Above, 0.8g / cm ３ Above, 0.85g / cm ３Above, 0.9g / cm ３ Above, 0.95g / cm ３ Above, 1.0g / cm ３ The density of the aramid paper is 1.5 g / cm ３ In particular, in the first embodiment, the density of the aramid paper is preferably 0.65 g / cm or less. ３ 1.5g / cm or more ３ In a second embodiment, the density of the aramid paper is preferably 0.7 g / cm or less. ３ 1.5g / cm or more ３ It is preferable that the basis weight and / or density of the aramid paper is within the above ranges. By setting the basis weight and / or density of the aramid paper within the above ranges, the strength of the insulating film can be increased, and assembly can be improved. The density of the aramid paper in the insulating film can be calculated from the density of the resins other than the aramid paper that make up the insulating film, the thickness of each layer, the density of the entire insulating film, and the thickness of the entire insulating film.

[0112] Aramid staple fibers are fibers made from aramid and cut to a predetermined length. Examples of aramid staple fibers include "Conex (registered trademark)" and "Technora (registered trademark)" from Teijin Techno Products Co., Ltd., "Nomex (registered trademark)" and "Kevlar (registered trademark)" from DuPont, and "Tokuron (registered trademark)" from Tokushu Tokai Paper Co., Ltd.

[0113] The fineness of the aramid short fibers is preferably 0.05 dtex or more and less than 25 dtex. By setting the fineness of the aramid short fibers within the above range, aggregation can be suppressed when producing aramid paper by a wet papermaking method, and uniform aramid paper can be easily obtained.

[0114] The length of the aramid short fibers is preferably 1 mm or more and less than 25 mm. By setting the length of the aramid short fibers within the above range, the mechanical properties of the aramid paper can be improved, and the production efficiency when the aramid paper is produced by a wet papermaking method can be increased.

[0115] The aramid paper may contain aramid fibrids in addition to aramid short fibers. Aramid fibrids are film-like fine particles made of aramid, and are produced by methods described in, for example, Japanese Patent Publication Nos. 35-11851 and 37-5732.

[0116] (Adhesive Layer) In the first embodiment, the resin layer and the aramid paper are laminated via a pressure-sensitive adhesive or adhesive. That is, the present insulating film has an adhesive layer between the resin layer and the aramid paper. The pressure-sensitive adhesive or adhesive constituting the adhesive layer is not particularly limited, and adhesives containing tackifiers, phenolic resin adhesives, acrylic adhesives, melamine adhesives, silicone adhesives, epoxy adhesives, etc. may be used.

[0117] The above-mentioned pressure-sensitive adhesive or adhesive is preferably applied to the surface of at least one selected from the resin layer and the aramid paper. There are no particular limitations on the means for applying the pressure-sensitive adhesive or adhesive as long as it can be applied uniformly. The thickness of the pressure-sensitive adhesive or adhesive after application is not particularly limited, but is preferably 20 μm or less, more preferably 15 μm or less, and even more preferably 10 μm or less. The lower limit of the thickness of the pressure-sensitive adhesive or adhesive after application is not particularly limited, but is preferably, for example, 1 μm or more.

[0118] In this embodiment, a pressure-sensitive adhesive sheet containing the above-described pressure-sensitive adhesive or adhesive may be attached to at least one surface selected from the resin layer and the aramid paper. For example, a double-sided pressure-sensitive adhesive sheet may be used in which pressure-sensitive adhesive sheets containing the above-described pressure-sensitive adhesive or adhesive are attached to both surfaces of a resin layer.

[0119] (Method for manufacturing insulating film for motors) An insulating film for motors comprising a resin layer and aramid paper is preferably manufactured, for example, through the following steps: (1) a step of thermally laminating a resin film and aramid paper, (2) a step of bonding a resin film and aramid paper together via an adhesive, or (3) a step of bonding an extruded molten resin sheet with aramid paper. In addition, in the method for manufacturing an insulating film for motors, the aramid paper and / or the resin film may each be subjected to a press processing treatment, or the insulating film for motors comprising a resin layer and aramid paper may be subjected to a press processing treatment.

[0120] <Method for Producing Resin Film> The resin film can be produced by a general molding method, such as extrusion molding, injection molding, blow molding, vacuum forming, pressure forming, press molding, etc. In each molding method, the apparatus and processing conditions are not particularly limited, but from the viewpoints of productivity and thickness control, it is preferable to employ extrusion molding, in particular the T-die method.

[0121] The method for producing the resin film is not particularly limited, but for example, the constituent material of the film can be obtained as an unstretched or stretched film, and from the viewpoint of secondary processability, it is preferable to obtain it as an unstretched film. Note that an unstretched film is a film that is not actively stretched for the purpose of controlling the orientation of the sheet, and also includes a film that is oriented when taken up by a cast roll in the T-die method.

[0122] In the case of an unstretched film, for example, the constituent materials can be melt-kneaded, followed by extrusion molding and cooling. A known kneader such as a single-screw or twin-screw extruder can be used for the melt-kneading. Molding can be carried out, for example, by extrusion molding using a mold such as a T-die.

[0123] The resin film may be a laminated film. When producing a laminated film, the lamination method is not particularly limited, and for example, any of a coextrusion method in which the constituent materials of each layer are coextruded and laminated, an extrusion lamination method in which each layer is formed into a film shape and then laminated, and a thermocompression bonding method in which each layer is formed into a film shape and then thermocompression bonded may be used. From the viewpoint of productivity, however, the coextrusion method is preferable. Coextrusion methods include a multi-manifold method in which the constituent materials of each layer are joined at a die, a feed block method in which the materials are joined at a feed block, and the like, and any of these may be used.

[0124] The resin film may be subjected to a surface treatment, such as a plasma treatment or a corona treatment. Crystalline resins may be preheated at a temperature equal to or higher than the glass transition temperature to increase the crystallinity and thereby increase the density of the resin film. Examples of preheating methods include a heating method using a hot air circulating oven or a heating roll.

[0125] <Method for manufacturing aramid paper> Aramid paper is manufactured, for example, by mixing the above-mentioned aramid short fibers and aramid fibrids and then forming them into a sheet. For example, there is a method (airlaid method) in which the aramid short fibers and aramid fibrids are dry-blended, and then deposited in a sheet form using an airflow to form a sheet, or a method in which the aramid short fibers and aramid fibrids are dispersed and mixed in a liquid medium to form a slurry, and then the slurry is wet-laid papermaking. In the wet papermaking method, an aqueous slurry containing at least aramid fibrids and aramid short fibers is sent to a papermaking machine and dispersed, and then dehydrated, squeezed, and dried to form a sheet. As the papermaking machine, a Fourdrinier papermaking machine, a cylinder papermaking machine, an inclined papermaking machine, or a combination papermaking machine combining these may be used. Additives such as a dispersibility improver, an antifoaming agent, and a paper strength enhancer may be added to the slurry as needed.

[0126] Before the step of forming the aramid paper, the aramid short fibers and / or aramid fibrids may be subjected to a beating treatment. By performing the beating treatment, the specific surface area of ​​the aramid and / or aramid fibrids can be increased, and the strength of the aramid paper can be effectively increased.

[0127] After the aramid paper forming step, a press processing may be performed as needed. The press processing can include, for example, calendering. In calendering, a hot and pressure treatment is performed between a pair of rolls at high temperature and high pressure. This can improve the smoothness of the aramid paper, as well as its density and mechanical strength. The heating temperature during the press processing is preferably 260°C or higher, more preferably 280°C or higher, even more preferably 300°C or higher, and particularly preferably 320°C or higher. The upper limit of the heating temperature is not particularly limited, but is preferably, for example, 500°C or lower, depending on the upper limit of the equipment. The pressure during the press processing is preferably 0.1 MPa or higher, more preferably 0.2 MPa or higher, and even more preferably 0.3 MPa or higher. The upper limit of the pressure is not particularly limited, but is preferably, for example, 20 MPa or lower, depending on the upper limit of the equipment.

[0128] <Lamination Method> When the manufacturing method for an insulating film for motors includes the above-mentioned step (1) (a step of thermally laminating a resin film and aramid paper), the method of laminating the aramid paper and the resin film includes heating, pressure processing, or a heating and pressure processing method (hot press method). In this embodiment, a step of preheating the resin film may be provided before laminating the aramid paper and the resin film and subjecting them to heating and / or pressure processing. In the preheating step, the resin film is preheated using, for example, a roll heater or an infrared heater. The heating temperature is preferably set to a temperature equal to or lower than the softening temperature of the resin.

[0129] After the preheating step of the resin film, it is preferable to provide a step of laminating the preheated resin film and aramid paper and hot pressing them. Examples of the hot pressing step include a method of laminating the laminate of the resin film and aramid paper by hot pressing, or a step of passing the laminate between a pair of heated rolls. The hot pressing conditions are preferably 260°C or higher, which is the softening temperature of the resin, more preferably 280°C or higher, even more preferably 300°C or higher, and particularly preferably 320°C or higher. The upper limit of the heating temperature is not particularly limited, but is preferably, for example, 500°C or lower, depending on the upper limit of the apparatus. The pressure during hot pressing is preferably 0.1 MPa or higher, more preferably 0.2 MPa or higher, and even more preferably 0.3 MPa or higher. The upper limit of the pressure is not particularly limited, but is preferably, for example, 20 MPa or lower, depending on the upper limit of the apparatus.

[0130] When the manufacturing method of an insulating film for motors includes the above-mentioned step (2) (a step of bonding a resin film and aramid paper via an adhesive), the pressure-sensitive adhesive or adhesive is preferably applied to the surface of at least one selected from the resin film and the aramid paper. The means for applying the pressure-sensitive adhesive or adhesive is not particularly limited as long as it can be applied uniformly. For example, it is preferable to apply the pressure-sensitive adhesive or adhesive using a gravure roll coater, reverse roll coater, kiss roll coater, dip roll coater, bar coater, knife coater, or spray coater.

[0131] In addition, the present embodiment may include a step of laminating a pressure-sensitive adhesive sheet containing the above-described pressure-sensitive adhesive or adhesive to the surface of at least one selected from the resin film and the aramid paper. Alternatively, lamination of the resin layer and the aramid paper may be performed using a double-sided pressure-sensitive adhesive sheet in which pressure-sensitive adhesive sheets containing the above-described pressure-sensitive adhesive or adhesive are previously laminated to both sides of a resin film.

[0132] When the manufacturing method for an insulating film for a motor includes the above-mentioned step (3) (a step of laminating an extruded molten resin sheet with aramid paper), the constituent materials of the resin film are melt-kneaded, and then the aramid paper is laminated to the extruded sheet. The extrusion temperature is preferably 260°C or higher, which is the softening temperature of the resin, more preferably 280°C or higher, even more preferably 300°C or higher, and particularly preferably 320°C or higher. The upper limit of the heating temperature is not particularly limited, but is preferably, for example, 500°C or lower, depending on the upper limit of the equipment. The pressure during lamination is preferably 0.1 MPa or higher, more preferably 0.2 MPa or higher, and even more preferably 0.3 MPa or higher. The upper limit of the pressure is not particularly limited, but is preferably, for example, 20 MPa or lower, depending on the upper limit of the equipment.

[0133] In this embodiment, after laminating the resin layer and the aramid paper, the motor insulating film may be subjected to a press processing treatment. The press processing may be, for example, a calendering treatment. The heating temperature during the press processing is preferably 100°C or higher, more preferably 120°C or higher, and even more preferably 140°C or higher. The upper limit of the heating temperature is not particularly limited, but is preferably, for example, 400°C or lower, depending on the upper limit of the equipment. The pressure during the press processing is preferably 0.05 MPa or higher, more preferably 0.1 MPa or higher, and even more preferably 0.15 MPa or higher. The upper limit of the pressure is not particularly limited, but is preferably, for example, 10 MPa or lower, depending on the upper limit of the equipment.

[0134] (Applications) The insulating film is used in motors for home appliances, audio equipment, IT equipment, communication equipment, office automation equipment, medical equipment, healthcare equipment, business equipment, industrial equipment, and transportation equipment such as automobiles, railways, and ships. For example, it is used for insulation between coil bundles in motors and between coils and stators. In particular, the insulating film is preferably used for insulation between coils and stators, and is suitable as wedge paper or slot paper, and is particularly preferably used as slot paper. The slot paper is inserted so as to fit along the inner surface of the slot (groove) in the motor stator. The insulating film is resistant to deformation and cracking when inserted into the slot, so it can be used without problems of poor insulation.

[0135] The present embodiment may also relate to a motor including the insulating film for a motor described above. The insulating film is thin but has good assembly properties and insulating properties, and also has high thermal conductivity (heat transmission), and is therefore preferably used in small, high-output motors.

[0136] The features of the present invention will be explained in more detail below with reference to examples and comparative examples. The materials, amounts used, ratios, treatment contents, treatment procedures, etc. shown in the following examples can be changed as appropriate without departing from the spirit of the present invention. Therefore, the scope of the present invention should not be construed as being limited by the specific examples shown below.

[0137] (1) Thickness of Each Layer The cross section was observed using an optical microscope to measure the thickness of each layer.

[0138] (2) Overall Thickness of Insulating Film The insulating film for motors was cut into a 10 cm square, and the thickness was measured at nine points at 50 mm intervals using a dial gauge, and the average value was used as the overall thickness of the insulating film for motors. (3) Weighing of Insulating Film The insulating film for motors was cut into a 10 cm square, and the weight was measured using a weighing scale. Two points were measured using a vernier caliper at positions approximately 5 mm from the end in the vertical and horizontal directions, and the average value was multiplied to obtain the area. The weight was then divided by the area to calculate the weight of the insulating film.

[0139] (4) Density of Insulating Film The density of the insulating film was calculated by dividing the weight of the insulating film for motors by the thickness.

[0140] (5) Density of Aramid Paper The density of the aramid paper was calculated using the density of the resin that makes up the resin layer, the density of the adhesive that makes up the adhesive layer if an adhesive layer is present, the density of the entire insulating film, the thickness of each layer, and the thickness of the entire insulating film.

[0141] (6) Film Thickness Ratio The film thickness ratio (resin layer thickness / aramid paper total thickness) was calculated by dividing the resin layer thickness by the aramid paper total thickness.

[0142] (7) Dielectric Breakdown Strength Using a dielectric breakdown tester, the motor insulating film was sandwiched between two electrodes (φ6 mm), and the voltage was increased from 0 in air at a constant rate so that dielectric breakdown occurred in an average of 10 to 20 seconds. The voltage at which the test material broke down was divided by the thickness to calculate the dielectric breakdown strength.

[0143] (8) Compressive Strength: The insulating films prepared in the Examples and Comparative Examples were punched into strips using a punching blade measuring 12.7 mm (longitudinal) and 157 mm (transverse). The strips were then rolled lengthwise to prepare longitudinal (MD) test specimens. Next, a test specimen holder consisting of a block (outer frame) with a cylindrical recess and a removable disk (inner frame) was used. The disk was attached to the block, and the test specimen was sandwiched in the circular groove formed by the disk to support the test specimen. The block recess had an inner diameter of 49.8 mm and a depth of 6.35 mm. The disk outer diameter was 49.6 mm for film thicknesses of 100 μm, 49.5 mm for film thicknesses of 200 μm, and 49.3 mm for film thicknesses of 300 μm. The disk thickness was 6.35 mm. If the ends of the test specimens placed in the grooves of the test specimen holder overlapped, the excess was trimmed off. After placing the test specimen on the test specimen holder, a precision universal testing machine, Autograph AGS-X (manufactured by Shimadzu Corporation), was used to operate the tester until the test specimen was crushed, and the maximum compressive force at the time of crushing was measured and taken as the compressive strength.

[0144] (9) Assembly Efficiency The insulating films prepared in the Examples and Comparative Examples were cut into strips measuring 114 mm in length and 40 mm in width. These strips were then folded at right angles to the horizontal direction at two points 3.5 mm above and below the vertical direction (see (i) and (ii) in Figure 2 ), followed by vertically folds at two points 17.5 mm above and below the horizontal direction (see (iii) and (iv) in Figure 2 ) at right angles to the vertical direction to obtain slotted paper-shaped test specimens. Next, an assembly jig (see Figure 3 ) was prepared in a steel material (SS400) measuring 33 mm in length, 140 mm in width, and 100 mm high, with eight 20 mm long and 4.8 mm wide holes drilled at 10 mm intervals. The test specimens were inserted into each hole, ensuring that all folds (see (i) and (ii) in Figure 2 ) protruded outside the holes. Next, 100 pieces of 0.9 mm diameter copper wire cut to lengths of approximately 700 mm were prepared, and as shown in Figure 4, two sets of copper wire bundles consisting of 25 copper wires were inserted into the slot paper of each hole in the assembly jig so that they faced in opposite directions. After inserting the copper wires, the copper wire bundles protruding from the top and bottom of the assembly jig to a height of approximately 6 mm to 12 mm were struck with a hammer to compress the copper wire bundle height to 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. The test piece was then evaluated according to the following criteria: AA: No scratches were detected on the surface of the test piece; A: No tears or deformation such as dents were observed on the test piece; B: No tears were observed, but deformation such as dents was observed; and C: Tears were observed on the test piece.

[0145] (10) Thermal Transmission Coefficient The specific heat of the insulating film for motors was measured at 100°C using a differential scanning calorimeter (DSC), and the thermal diffusivity at 100°C was measured using a xenon flash analyzer. Then, the heat reflux rate was calculated using the following formula: Heat reflux rate [W / (m ２ ・K)]=(thermal diffusivity [m ２ / s] × specific heat [kJ / (kg·K)] × density [kg / m ３ ] x 1000) / thickness [m]

[0146] Example 1 Polyetherimide Ultem 1000-1000 (manufactured by Sabic, Tg = 213°C) was melt-kneaded using a 40 mm diameter single-screw extruder and continuously extruded through a T-die to obtain a resin film with a thickness of 50 μm. The extruder temperature and die temperature were both 380°C. Nomex (manufactured by DuPont Teijin Advanced Papers, 2 mil (approximately 50 μm) thick) aramid paper was used. The aramid paper, resin film, and aramid paper were laminated in this order and subjected to heat and pressure processing at a temperature of 310°C and a pressure of 1.1 MPa using a hydraulic heating press to obtain an insulating film for motors consisting of aramid paper / PEI layer / aramid paper. The overall thickness of the insulating film for motors was measured at nine points, with the maximum value being 127 μm. The resulting insulating film for motors had an interfacial structure in which a portion of the aramid paper was embedded in the resin layer.

[0147] Example 2 An insulating film for a motor was produced in the same manner as in Example 1, except that the aramid paper used was changed to TT-TOKRON (manufactured by Tokai Tokushu Paper Co., Ltd., thickness 2 mil) and the pressing pressure was changed to 0.8 MPa. The total thickness of the insulating film for a motor was measured at nine points, and the maximum value was 131 μm. The insulating film for a motor obtained had an interface structure in which part of the aramid paper was embedded in the resin layer.

[0148] Comparative Example 1 An insulating film for a motor was produced in the same manner as in Example 1, except that the thickness of the resin film was changed to 15 μm and the pressing pressure was changed to 0.6 MPa. The total thickness of the insulating film for a motor was measured at nine points, and the maximum value was 119 μm.

[0149] (Comparative Example 2) Using Nomex (manufactured by DuPont Teijin Advanced Papers, thickness 2 mil) as the aramid paper, aramid paper, double-sided film tape 7070W (manufactured by Teraoka Seisakusho, total thickness 0.01 mm), and aramid paper were laminated in this order, and a resin film was attached to the aramid paper to obtain an insulating film for a motor having a configuration of aramid paper / adhesive / PET / adhesive / aramid paper. The total thickness of the insulating film for a motor was measured at nine points, and the maximum value was 122 μm.

[0150] Comparative Example 3: Instead of the insulating film for motors obtained in the examples, an aramid paper Nomex (manufactured by DuPont Teijin Advanced Papers, Inc., thickness 5 mil) was used as an evaluation sample. The total thickness of the insulating film for motors was measured at nine points, and the maximum value was 152 μm.

[0151] (Comparative Example 4) Polyetherimide Ultem CRS5001-1000 (manufactured by Sabic, Tg = 225°C) was melt-kneaded using a Φ40 mm single-screw extruder and continuously extruded through a T-die to obtain a resin film with a thickness of 128 μm. The extruder temperature and die temperature were both 380°C. Instead of the insulating film for motors obtained in the examples, a resin film was used as an evaluation sample. The overall thickness of the insulating film for motors was measured at nine points, and the maximum value was 129 μm.

[0152] Comparative Example 5: Polyetherimide Ultem CRS5001-1000 (manufactured by Sabic, Tg = 225°C) was melt-kneaded using a 40 mm diameter single-screw extruder and continuously extruded through a T-die to obtain a resin film with a thickness of 75 μm. The extruder temperature and die temperature were both 380°C. Nomex (manufactured by DuPont Teijin Advanced Papers, thickness 2 mil) was used as the aramid paper. A polyester-epoxy urethane adhesive was applied to one side of the resin film using a bar coating method to a thickness of 10 μm, and the resin film was then bonded to the aramid paper to obtain an insulating film for motors consisting of an aramid paper / adhesive / PEI layer. The overall thickness of the insulating film for motors was measured at nine points, with the maximum value being 145 μm.

[0153] Comparative Example 6: An NPN (manufactured by Nitto Shinko Co., Ltd., thickness 210 μm) having a structure of aramid paper / adhesive / PEN layer / adhesive / aramid paper was used as an evaluation sample. The total thickness of the insulating film for motors was measured at nine points, and the maximum value was 223 μm.

[0154]

[0155] Example 3: Two 2-mil-thick aramid papers were heated and pressurized in a hydraulic heating press at 320°C and 1.0 MPa to obtain two 43-μm-thick sheets of aramid paper. A polyethylene naphthalate film, Teonex (Teijin, 38 μm thick), was used as the resin film. An adhesive prepared by dissolving maleic anhydride-modified styrene-based elastomer (Tuftec M1943, Asahi Kasei; styrene / ethylene-butylene = 20 / 80 mol%, oxidation = 10 mg CH3Ona / g) in toluene to a concentration of 10 wt % was applied to both sides of the resin film to a dry thickness of 5 μm. Aramid paper was then laminated onto the adhesive-coated resin film, and the resulting laminate was heated and pressurized in a hydraulic heating press at 180°C and 0.1 MPa to obtain an insulating film for a motor consisting of aramid paper / adhesive / PEN layer / adhesive / aramid paper. The total thickness of the insulating film for motors was measured at nine points, and the maximum value was 135 μm.

[0156] (Comparative Examples 1 to 6) The above-described comparative examples 1 to 6 were similar comparative examples.

[0157]

[0158] The insulating films for motors obtained in the above examples were excellent in insulation properties, as well as in ease of assembly and thermal conductivity. In particular, Examples 1 and 2, which had high film densities, had excellent ease of assembly. On the other hand, the comparative examples were inferior in at least one of insulation properties, ease of assembly, and thermal conductivity.

[0159] 2 Resin layer 4 Aramid paper 6 Adhesive layer 10 Motor insulating film

Claims

1. An insulating film for motors comprising a resin layer and aramid paper laminated on both sides of the resin layer via an adhesive layer, the thickness of the insulating film for motors being 200 μm or less and the density being 1.0 g / cm ３ or more, wherein the thickness of the aramid paper is 49 μm or less and the density is 0.65 g / cm ３ 1.50g / cm or more ３ or less, and a value obtained by dividing the thickness of the resin layer by the total thickness of the aramid paper is 0.4 to 5.

2. An insulating film for a motor comprising a resin layer and aramid paper laminated on both sides of the resin layer, wherein the density of the insulating film for a motor is 1.2 g / cm ３ or more, and the density of the aramid paper is 0.7 g / cm ３ 1.50g / cm or more ３ or less, and a value obtained by dividing the thickness of the resin layer by the total thickness of the aramid paper is 0.4 to 5.

3. The insulating film for motors according to claim 1 or 2, which has a dielectric breakdown strength of 50 kV / mm or more.

4. The insulating film for motors according to claim 1 or 2, which has a compressive strength of 100 N or more.

5. The insulating film for a motor according to claim 2, wherein at least one of the aramid papers has a thickness of 49 μm or less.

6. The insulating film for motors according to claim 1 or 2, wherein the resin layer has a thickness of 30 μm or more.

7. The insulating film for motors according to claim 1 or 2, wherein the resin layer is at least one selected from the group consisting of polyetherimide, polyether ether ketone, polyimide, polyphenylene sulfide, polyethylene naphthalate, and polyethylene terephthalate.

8. The insulating film for a motor according to claim 2, wherein the insulating film has an interface structure in which a portion of the aramid paper is embedded in the resin layer.

9. The insulating film for motors according to claim 2, wherein aramid paper is fused to the resin layer.

10. The insulating film for motors according to claim 1 or 2, which is a slotted paper.

11. A motor equipped with the insulating film for motors according to claim 1 or 2.

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