Polyarylene sulfide film

Abstract

The present invention aims to provide a polyarylene sulfide film that exhibits excellent voltage resistance characteristics in high-temperature environments and can improve the long-term stability of film capacitors when used as a dielectric. [Solution] A polyarylene sulfide film characterized by containing crystalline component A having a melting point of 145°C or higher and 220°C or lower, and crystalline component B having a melting point higher than 220°C and 340°C or lower.

Description

[Technical Field]

[0001] This invention relates to a polyarylene sulfide film. [Background technology]

[0002] Polyphenylene sulfide film, one type of polyarylene sulfide film, is disclosed in Patent Document 1, etc. (Hereafter, polyphenylene sulfide may be referred to as PPS). Furthermore, Patent Document 2, etc., proposes that by using PPS film as the dielectric of a film capacitor, it is possible to provide a film capacitor with excellent heat resistance, frequency characteristics, temperature characteristics, etc.

[0003] However, the film capacitors described above have a drawback: their manufacturing process, specifically winding, cutting, and molding, has a narrow range of manufacturing conditions, and insufficient control of these conditions can lead to variations in the physical properties within the film surface, resulting in an increase in defective products due to low-voltage breakdown. Furthermore, these film capacitors often short-circuit without self-healing when low-voltage breakdown occurs, and also have other drawbacks such as increased defect rates and reduced reliability during use.

[0004] To overcome these drawbacks, there have been proposals to improve the properties of PPS films using polymer blends or alloys (Patent Documents 3-5). For example, Patent Document 3 proposes a method to improve the tear resistance of a PPS film by blending PPS with polyetherimide and controlling the dispersion diameter of the polyetherimide to be 30 μm or less, while Patent Documents 4 and 5 propose a method to improve the dielectric strength of a film by making polyetherimide compatible with PPS and forming a film. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 54-142275 [Patent Document 2] Japanese Patent Publication No. 57-187327 [Patent Document 3] Japanese Patent Application Laid-Open No. 62-158312 [Patent Document 4] Japanese Patent Publication No. 2001-261959 [Patent Document 5] Japanese Patent Publication No. 2008-280508 [Overview of the Initiative] [Problems that the invention aims to solve]

[0006] However, the method described in Patent Document 3 only improves the tear resistance of the resulting PPS film, and does not consider improving its electrical properties or the characteristics of film capacitors when used as a dielectric. Furthermore, the methods described in Patent Documents 4 and 5 have difficulty achieving voltage resistance at high temperatures suitable for automotive applications and other uses where reliability is required, due to issues such as the generation of foreign matter as a side reaction by the compatibilizer promotes crosslinking of the resin, and the bleeding out of side reaction components over time.

[0007] The present invention aims to provide a polyarylene sulfide film that exhibits excellent voltage resistance characteristics in high-temperature environments and can improve the long-term stability of film capacitors when used as a dielectric. [Means for solving the problem]

[0008] The polyarylene sulfide film of the present invention has the following configuration in order to solve the above problems. That is, the polyarylene sulfide film of the present invention is a polyarylene sulfide film characterized by containing crystalline component A having a melting point of 145°C or more and 220°C or less, and crystalline component B having a melting point higher than 220°C and 340°C or less.

[0009] Furthermore, the polyarylene sulfide film of the present invention can be in the following forms, and can be used to obtain metal laminates, film capacitors, power control units, electric vehicles, and electric aircraft. The polyarylene sulfide film of the present invention can also be manufactured, for example, by the following manufacturing method. (1) A polyarylene sulfide film characterized by containing crystalline component A having a melting point of 145°C or higher and 220°C or lower, and crystalline component B having a melting point higher than 220°C and 340°C or lower. (2) The polyarylene sulfide film according to (1), wherein, when the total heat of fusion of the crystalline component of the entire polyarylene sulfide film is taken as 100%, the heat of fusion of the crystalline component A is 0.01% or more and 49% or less. (3) The polyarylene sulfide film according to (1) or (2), wherein, when measuring the endothermic peaks of the polyarylene sulfide film, the number of endothermic peaks observed during the first heating process is greater than the number of endothermic peaks observed during the second heating process. (4) A polyarylene sulfide film according to any one of (1) to (3), wherein the value of the longitudinal tanδ at 150°C, as measured by dynamic viscoelasticity measurement, is 0.001 or more and 0.15 or less. (5) A polyarylene sulfide film according to any of (1) to (4), wherein the coefficient of variation of the thickness when the thickness is measured at 30 points at 5 cm intervals in the longitudinal direction is 0% or more and 20% or less. (6) The polyarylene sulfide film according to any one of (1) to (5), wherein when the total mass of all components constituting the polyarylene sulfide film is taken as 100% by mass, more than 50% by mass and less than or equal to 100% by mass is polyphenylene sulfide. (7) A polyarylene sulfide film according to any one of (1) to (6), wherein at least one outermost layer has a resin layer A containing at least one resin selected from the group consisting of urethane acrylate polymer, acrylate polymer, urethane methacrylate polymer, methacrylate polymer, aliphatic polyether, aliphatic polyester, aliphatic polyamide, polyurethane, and polyurea. (8) The polyarylene sulfide film according to any one of (1) to (7), which is a film for a film capacitor. (9) A metal laminate having a metal layer on at least one surface of the polyarylene sulfide film according to any one of (1) to (8). (10) A film capacitor using the metal laminate according to (9). (11) A power control unit having the film capacitor according to (10). (12) An electric vehicle having the power control unit according to (11). (13) An electric aircraft having the power control unit according to (11). (14) A method for manufacturing a film capacitor, including the following steps 1 and 2. Step 1: Wind up the metal laminate according to claim 9 to form a wound body. Step 2: Heat-treat the wound body at 130°C or higher and 205°C or lower for 80 hours or more and 1000 hours or less.

Advantages of the Invention

[0010] According to the present invention, a polyarylene sulfide film can be provided, which has excellent withstand voltage characteristics in a high-temperature environment and can improve the long-term stability of a film capacitor by being used as a dielectric.

Embodiments for Carrying out the Invention

[0011] Hereinafter, the polyarylene sulfide film of the present invention will be described. The polyarylene sulfide film of the present invention is characterized by containing a crystal component A having a melting point of 145°C or higher and 220°C or lower, and a crystal component B having a melting point higher than 220°C and 340°C or lower.

[0012] In the present invention, the polyarylene sulfide film refers to a film formed by melt-molding a resin composition mainly composed of a polyarylene sulfide (hereinafter sometimes referred to as PAS) resin into a sheet shape. The PAS film may be stretched, and preferably is biaxially stretched.

[0013] In the present invention, when a PAS-based resin is used as the main constituent (main component), it means that the PAS-based resin is contained in an amount of more than 50% by mass and 100% by mass or less, preferably 60% by mass or more and 100% by mass or less, more preferably 70% by mass or more and 100% by mass or less. If the content of the PAS-based resin is 50% by mass or less, the heat resistance, dimensional stability, and mechanical properties, which are the characteristics of the film, may be impaired. Hereinafter, the same interpretation can be applied to the main component.

[0014] In the present invention, the PAS-based resin is a homopolymer or copolymer that contains more than 50 mol% and 100 mol% or less of the repeating unit of "-(Ar-S)-" when the total constituent units constituting the resin are 100 mol%. Here, Ar means an arylene group, and examples of Ar include groups represented by the following formulas (A) to (K). In some cases, the constituent unit contained most in the following total constituent units may be referred to as the main constituent unit.

[0015] [Chemical formula]

[0016] (Here, R1 and R2 are substituents selected from a hydrogen atom, an alkyl group, an alkoxy group, and a halogen group, and R1 and R2 may be the same or different.) As the constituent unit of the PAS-based resin, the p-arylene sulfide unit represented by the above formula (A) is preferable. Representative examples thereof include polyphenylene sulfide, polysulfone, polyethersulfone, polyphenylene sulfide sulfone, polyphenylene sulfide ketone, and the like. Particularly preferable p-arylene sulfide units include p-phenylene sulfide units from the viewpoints of the physical properties and economy of the obtained polyarylene sulfide film.

[0017] The PAS resin used in the PAS film of the present invention preferably contains p-phenylene sulfide units represented by the following structural formula, with a concentration of more than 50 mol% and up to 100 mol%, more preferably between 80 mol% and 99.9 mol% of the total constituent units. In other words, the PAS film of the present invention preferably contains polyphenylene sulfide, with a concentration of more than 50% and up to 100% by mass, when the total mass of the components constituting the PAS film is taken as 100% by mass. By adopting this configuration, the PAS film of the present invention can be made to obtain a polyarylene sulfide film with excellent heat resistance and voltage resistance characteristics.

[0018] [ka]

[0019] Furthermore, the PAS resin may contain copolymerized constituent units represented by the following chemical formula in an amount of 0.01 mol% to 20 mol% of the total constituent units. The form of the copolymer is not particularly limited, but from the viewpoint of compatibility, a random copolymer is preferred.

[0020] The following are examples of preferred copolymer units, with the m-phenylene sulfide unit being particularly preferred.

[0021] [ka]

[0022] [ka]

[0023] [ka]

[0024] (Here, X represents alkylene, CO, and SO2 units.)

[0025] [ka]

[0026] [ka]

[0027] (Here, R represents an alkyl, nitro, phenylene, or alkoxy group.) The PAS film of the present invention preferably has a maximum dw / dlog(M) value of 0.70 or more and 1.5 or less. A dw / dlog(M) of 0.70 or more for the PAS film means that the PAS film is composed of a PAS-based resin with a narrower molecular weight distribution. This configuration makes it easier to control the content of crystalline component A, tanδ, and the coefficient of variation of thickness, which will be described later, to a suitable range, and makes it easier to improve the dielectric strength and long-term stability when the PAS film of the present invention is used as a film capacitor. From the above viewpoint, the maximum dw / dlog(M) value of the PAS film is more preferably 0.80 or more, even more preferably 0.90 or more, and particularly preferably 1.0 or more. On the other hand, the film-forming properties are improved when the maximum dw / dlog(M) value of the PAS film is 1.5 or less. From the above viewpoint, the maximum dw / dlog(M) value of the PAS film is more preferably 1.2 or less. Note that dw / dlog(M) can be measured by molecular weight measurement using GPC, and the details of the measurement method will be described later.

[0028] Methods for adjusting the maximum value of dw / dlog(M) of the PAS film of the present invention to the above range include using a PAS-based resin as a raw material in which the maximum value of dw / dlog(M) is within the above range, or using a raw material obtained by mixing multiple PAS-based resins with different molecular weight distributions and adjusting the molecular weight distribution so that the value of dw / dlog(M) falls within the above range. Furthermore, the PAS-based resin constituting the PAS film of the present invention may contain various additives such as antioxidants, heat stabilizers, antistatic agents, and antiblocking agents, to the extent that they do not impair the effects of the present invention.

[0029] The PAS film of the present invention may contain inert particles or other thermoplastic resins (X) from the viewpoint of improving processability. From the viewpoint of film-forming properties, the content of inert particles or other thermoplastic resins is preferably 1% by mass or less when the total mass of the PAS film is 100% by mass, and from the viewpoint of improving processability, it is preferably 0.01% by mass or more.

[0030] Examples of inert particles suitable for application to the PAS film of the present invention include inorganic particles such as silica, alumina, calcium carbonate, barium carbonate, barium titanate, barium sulfate, calcium silicate, magnesium oxide, titanium oxide, and zinc oxide. Among these, calcium carbonate is preferred from the viewpoint of manufacturing cost. These components may be used individually or in combination of multiple types.

[0031] Furthermore, as thermoplastic resins (X) suitably applicable to the PAS film of the present invention, for example, polyarylate, polyphenylene ether, polyetherimide, polysulfone, polyphenylsulfone, and polyethersulfone can be used, but from the viewpoint of affinity with the PAS resin, polysulfone, polyphenylsulfone, and polyethersulfone are preferably used. Note that these components may be used individually, in combination of multiple types, or in combination with the inert particles mentioned above.

[0032] The PAS film of the present invention may have a laminated structure having two or more layers in which PAS resin is the main component, from the viewpoint of adjusting stretchability and processability. Furthermore, examples of laminated structures include a 3-layer structure of A / B / C, a 3-layer structure of A / B / A, and a 2-layer structure of A / B, where layers containing different components are made up of layers A, B, C, etc.

[0033] The PAS film of the present invention is important because, when used as a dielectric in a film capacitor, it contains crystalline component A with a melting point of 145°C to 220°C and crystalline component B with a melting point higher than 220°C and 340°C or lower, in order to reduce the decrease in withstand voltage due to the occurrence of insulation defects. The melting point can be measured in accordance with JIS K-7122 (1987) (details are described later).

[0034] The PAS films manufactured by the methods described in Patent Documents 1 to 5 all contain only crystalline component B. When such PAS films are used as dielectrics in film capacitors at temperatures of 150°C or higher, the rigid molecular chains of the PAS resin prevent components from becoming crystalline component B, which has a high melting point and high orderliness. This prevents these components from becoming crystalline component B, leading to insulation defects and a decrease in withstand voltage. The PAS film of the present invention densely contains crystalline component A, which has a low melting point and low orderliness, in addition to crystalline component B. This reduces the occurrence of insulation defects due to the above mechanism and increases the withstand voltage. Furthermore, when a PAS film containing crystalline components A and B is used as a dielectric in a film capacitor, the degree of crystallinity of the PAS film is less likely to change over time during use, resulting in a highly reliable film capacitor with stable performance.

[0035] From the above viewpoint, the melting point of crystalline component A is preferably 150°C to 210°C, and more preferably 175°C to 200°C. Similarly, from the same viewpoint, the melting point of crystalline component B is preferably 250°C to 300°C, and even more preferably 250°C to 288°C.

[0036] The method for incorporating crystalline component B into the PAS film of the present invention is not particularly limited, but one example is to perform a heat treatment at a temperature of 220°C to 290°C, preferably 220°C to 280°C, after biaxial stretching during the film-forming process of the PAS film. As a method for incorporating crystalline component A into the PAS film, one example is to heat-age the PAS film at a temperature of 130°C to 205°C (preferably above 130°C and below 205°C, more preferably 140°C to 200°C, and even more preferably 140°C to 175°C) for 80 hours or more (preferably 100 hours or more) after winding the PAS film. From the viewpoint of improving the performance of the film capacitor, the above treatment may be performed after processing into the shape of a film capacitor (preferably under the same conditions).

[0037] As described in prior art (Patent Documents 4 and 5), it is common practice to stabilize the performance of film capacitors by heat-treating them for about 1 to 10 hours depending on the operating environment. However, the inventors have diligently studied and found that by forming the PAS film of the present invention by heat-treating it for a long period of time under specific conditions not described in the aforementioned prior art, a film capacitor with outstandingly superior heat resistance and voltage resistance can be obtained. Furthermore, focusing on the raw material, by using a PAS-based resin containing a PAS-based resin with a melting point of 270°C or higher as measured by differential scanning calorimetry, the orderliness of the PAS-based resin crystals is increased, making it easier to incorporate crystalline components A and B. In addition, by using a PAS raw material in which the dw / dlog(M) of the PAS-based resin is within the above-mentioned preferred range, it is also easy to incorporate crystalline components A and B into the PAS film. The above methods can be used in combination as appropriate.

[0038] From the viewpoint of achieving both heat resistance and dielectric strength, the PAS film of the present invention preferably has a dielectric strength of 0.01% to 49% of the dielectric strength of crystalline component A when the dielectric strength of the crystalline components of the entire film is taken as 100%. From the viewpoint of improving the dielectric strength of the PAS film, the dielectric strength of crystalline component A is more preferably 0.1% or more, even more preferably 0.5% or more, and particularly preferably 1.5% or more. On the other hand, from the viewpoint of increasing the heat resistance of the PAS film, it is preferable to have a large amount of crystalline component B, so the dielectric strength of crystalline component A is more preferably 30% or less, even more preferably 15% or less, and particularly preferably 5.0% or less.

[0039] There are no particular limitations on the method for adjusting the heat of fusion of crystalline component A, but adjusting the conditions of heat treatment and heating aging is effective. More specifically, the heat of fusion of crystalline component A can be increased by extending the time or raising the temperature within a suitable range, and the heat of fusion of crystalline component A can be decreased by shortening the time or lowering the temperature. Furthermore, on the raw material side, using PAS-based resins with a dw / dlog(M) within the aforementioned suitable range also contributes to increasing the heat of fusion of crystalline component A. These methods may be used in combination as appropriate.

[0040] From the viewpoint of improving heat resistance, it is preferable that the PAS film of the present invention has more endothermic peaks observed during the first heating process than during the second heating process when its endothermic peaks are measured. From the above viewpoint, it is preferable that among the endothermic peaks observed during the first heating process, the peaks at relatively lower temperatures disappear during the second heating process, thereby reducing the number of endothermic peaks. Adopting such an embodiment means reducing the amount of low-melting-point resin components, and by adopting such an embodiment, the heat resistance of the PAS film is improved. The endothermic peaks can be measured by the following method 1.

[0041] Method 1: Using a differential scanning calorimeter, 5 mg of the polyarylene sulfide film is heated from 25°C to 350°C at a rate of 20°C / min in a nitrogen atmosphere, held at 350°C for 5 minutes, and then cooled from 350°C to below 25°C at a rate of 10°C / min. Next, the temperature is raised from 25°C to 350°C at a rate of 20°C / min and held at 350°C for 5 minutes. The same measurement is performed three times, and the average number of endothermic peaks observed during the first and second heating processes is taken as the number of endothermic peaks for each heating process.

[0042] The differential scanning calorimeter used in Method 1 is not particularly limited as long as it is capable of measurement, and any known instrument can be used. An example of a usable instrument is the Seiko Instruments EXSTAR DSC6220, and details of the measurement method using this instrument will be described later.

[0043] One method for producing a PAS film in which the number of endothermic peaks observed during the first heating process is greater than the number of endothermic peaks observed during the second heating process is to perform heat treatment after winding the PAS film. The preferred conditions for the heat treatment are as described above.

[0044] The PAS film of the present invention preferably has a longitudinal tanδ value of 0.001 or more and 0.15 or less at 150°C, as measured by dynamic viscoelasticity measurement. The longitudinal tanδ at 150°C corresponds to the mobility of the PAS resin molecules, and the lower the tanδ, the more stable the polymer structure. Therefore, a tanδ of 0.15 or less in the PAS film means that when used as a dielectric in a film capacitor, the long-term stability of the dielectric strength is increased, i.e., it becomes a capacitor with superior reliability. From the above viewpoint, the lower the tanδ, the better. On the other hand, from the viewpoint of feasibility, the tanδ is preferably 0.001 or more, more preferably 0.010 or more, and even more preferably 0.050 or more.

[0045] The method for setting the tanδ of the PAS film to 0.001 or more and 0.15 or within the above preferred range is not particularly limited, but examples include using a PAS raw material in which the dw / dlog(M) of the PAS resin in the PAS film is within the above preferred range, or obtaining a biaxially oriented PAS film by sequentially stretching the PAS film using a biaxial stretching method, and then performing a heat treatment at a temperature of 130°C or higher (preferably 140°C or higher, more preferably 150°C or higher) for 80 hours or more (preferably 100 hours or more, more preferably 100 hours or more and 160 hours or less). These methods can be used in combination as appropriate.

[0046] In the PAS film of the present invention, "longitudinal direction" refers to the direction corresponding to the flow direction in the film manufacturing process (hereinafter sometimes referred to as "MD"), and if the film sample is in the shape of a reel, roll, winding body, film capacitor, etc., this corresponds to the film winding direction. Furthermore, "width direction" refers to the direction perpendicular to the longitudinal direction within the film surface (hereinafter sometimes referred to as "TD"). On the other hand, in the case of a film where it is unclear from the appearance of the film which direction is the longitudinal direction, lines are drawn at 15° intervals based on an arbitrary straight line on the film plane, slit-shaped film pieces parallel to each line are sampled, and the breaking strength is determined using a tensile tester. The direction that gives the maximum breaking strength is considered to be the width direction of the film, and the direction perpendicular to the width direction is considered to be the longitudinal direction. The breaking strength can be measured by the following procedure.

[0047] First, a rectangular piece of PAS film (width (short side) 10 mm × length (long side) 150 mm), cut with the length direction as the longer side, is used as the measurement sample. Next, the sample is set in a tensile testing machine (for example, Orientec's "Tensilon" (registered trademark) UCT-100 can be used) with an initial chuck distance of 20 mm, and a tensile test of the film is performed in a room at 23°C at a tensile speed of 300 mm / min. At this time, the position of the sample in the longitudinal direction is adjusted so that the center of the sample is near the middle of the chucks. The load applied to the film at the time of sample fracture is read, and the value obtained by dividing it by the cross-sectional area of ​​the sample before the test (film thickness × width (10 mm)) is calculated as the breaking strength (unit: MPa).

[0048] The PAS film of the present invention preferably has a coefficient of variation of thickness of 0% or more and 20% or less when the thickness is measured at 30 points at 5 cm intervals in the longitudinal direction (hereinafter, the coefficient of variation of thickness when the thickness is measured at 30 points at 5 cm intervals in the longitudinal direction may be simply referred to as the "coefficient of variation of thickness"). In the PAS film of the present invention, the coefficient of variation of thickness refers to the sample standard deviation of the above 30 thickness measurements divided by the sample mean (details of the measurement method will be described later).

[0049] By setting the coefficient of variation of thickness within a suitable range, it is possible to reduce the risk of the PAS film of the present invention becoming distorted and reducing yield when processed into film capacitors, and to stabilize its shape even when exposed to high-temperature environments during processing into film capacitors or during long-term use, thereby improving the reliability of the film capacitors.

[0050] From the above viewpoint, the smaller the coefficient of variation of thickness, the more preferable it is, more preferably 10% or less, and even more preferably 5.0% or less. On the other hand, the lower limit of the coefficient of variation of thickness is theoretically 0%, which means that the thickness of the 30 points mentioned above is constant. Methods for lowering the coefficient of variation of thickness of the PAS film are not particularly limited, but include using a PAS raw material in which the maximum value of dw / dlog(M) of PAS in the PAS film is within the preferred range described above when manufacturing the PAS film, and stretching in the longitudinal direction by a magnification of preferably 2.9 times or more, more preferably 3.4 times or more. In addition, if heat treatment is performed after the PAS film is wound, the coefficient of variation of thickness will increase, but by setting the heat treatment time within the preferred range described above, it becomes easy to set the coefficient of variation of thickness within the preferred range described above. These methods can be used in combination as appropriate.

[0051] The PAS film of the present invention preferably has a resin layer A in at least one of its outermost layers, which contains at least one resin selected from the group consisting of urethane acrylate polymer, acrylate polymer, urethane methacrylate polymer, methacrylate polymer, aliphatic polyether, aliphatic polyester, aliphatic polyamide, polyurethane, and polyurea. Since these resins are softer than PAS, by providing the resin layer A, when a metal laminate with a metal layer on a PAS film is wound into a film capacitor shape and heat-treated for a long time, winding misalignment and deformation can be suppressed, and the reliability of the resulting film capacitor can be improved.

[0052] From the above viewpoint, it is more preferable that the resin layer A contains at least one resin from the group consisting of urethane acrylate polymer, urethane methacrylate polymer, polyurethane, and polyurea, and even more preferable that it contains at least one resin from the group consisting of urethane acrylate polymer and urethane methacrylate polymer, from the viewpoint of increasing moisture and heat resistance. Urethane acrylate polymer refers to a compound obtained by polymerizing acrylate containing urethane bonds. Acrylate polymer refers to a compound obtained by polymerizing acrylate other than urethane acrylate polymer. Aliphatic polyether, aliphatic polyester, and aliphatic polyamide refer to resins having a structure in which aliphatic hydrocarbon groups are linked by ether bonds, ester bonds, and amide bonds, respectively.

[0053] The resins in the above resin group may be a mixture of two or more types, or may contain at least one compound that contains two or more constituent units of the above resin group. The constituent units of the above resin group refer to the following structures 1 to 7 (the correspondence will be described later). Among the above resin group, urethane acrylate polymer and urethane methacrylate polymer have two types of structures as constituent units, and if both of these structures are included, the resin is considered to contain one of these constituent units. In the case of a compound having multiple constituent units, it is determined whether each compound is applicable, for example, a resin layer containing a compound having structures 1, 2 and 3 as constituent units is treated as containing urethane acrylate polymer, acrylate polymer, urethane methacrylate polymer, and methacrylate polymer. The above resin may contain components with structures other than those listed below. When the total mass of resin layer A is 100% by mass, the mass ratio W of components having the following structures 1 to 7. A It is preferable that the resin layer A contains a resin consisting of the above resin group such that the amount is 1% by mass or more. However, the mass of the X, Y, and Z parts of structures 1 to 6 is W A It shall not be included in the above W. A It is preferable that the amount is 5% by mass or more, more preferably 10% by mass or more, and particularly preferably 40% by mass or more. Also, W A There is no particular upper limit, but theoretically it is 100% by mass. Urethane acrylate polymer: Structure 1 and Structure 2 Acrylates polymer: Structure 1 Urethane methacrylate polymer: Structure 2 and Structure 3 Methacrylate polymer: Structure 3 Aliphatic polyether: Structure 4 Aliphatic polyester: Structure 5 Aliphatic polyamide: Structure 6 Polyurethane: Structure 2 Polyurea: Structure 7

[0054] [ka]

[0055] Here, n is an integer greater than or equal to 1. R1 and R2 represent aliphatic hydrocarbon groups, and X, Y, and Z represent arbitrary chemical structures. Some of these may have the same chemical structure, or they may all have different chemical structures.

[0056] Whether resin layer A contains the above constituent units (structures 1 to 7) can be determined, for example, 1 They can be identified by analyzing them using methods commonly used for structural analysis of polymers, such as 1H-NMR (nuclear magnetic resonance spectroscopy), time-of-flight secondary ion mass spectrometry (also known as TOF-SIMS), and Fourier transform infrared spectroscopy (also known as FT-IR).

[0057] Next, the method for producing the PAS film of the present invention will be explained using polyphenylene sulfide resin (hereinafter sometimes abbreviated as PPS resin) as the PAS-based resin, with a two-layer structure consisting of resin layer A and a layer mainly composed of PAS (hereinafter referred to as resin layer B) as an example. However, the PAS film of the present invention may have a structure that does not include resin layer A, or a structure of two or more layers having other layers.

[0058] First, sodium sulfide and p-dichlorobenzene are combined and reacted under high temperature and pressure in an amide-based polar solvent such as N-methyl-2-pyrrolidone (NMP). Copolymer components such as m-dichlorobenzene and trihalobenzene can be added as needed. Caustic potash or alkali metal carboxylates are added as polymerization modifiers and the polymerization reaction is carried out at 240-290°C. After polymerization, the polymer is cooled, filtered as an aqueous slurry, and a wet granular polymer is obtained. This granular polymer is washed by adding an amide-based polar solvent and stirring at a temperature of 30-100°C, washed several times with deionized water at 30-80°C, washed several times with an aqueous solution of a metal salt such as calcium acetate, and then dried to obtain PPS powder.

[0059] Next, the PPS film that will become resin layer B is manufactured by the following method. First, PPS chips that have been dried under reduced pressure at 180°C for 3 hours as needed are mixed with a masterbatch containing the above-mentioned inert particles, etc., in a predetermined ratio and supplied to a full-flight single-screw extruder set to a molten section of 300-350°C. After passing through a filter, it is extruded in a sheet form from a T-die type die. This molten sheet is rapidly cooled and solidified by adhering it to a cooling drum with a surface temperature of 20-60°C while applying an electrostatic charge, thereby obtaining an unoriented, unstretched film.

[0060] Next, the unstretched film obtained above is biaxially stretched using a sequential biaxial stretcher or a simultaneous biaxial stretcher at a temperature of 80°C to 150°C, and then subjected to a one-stage or multi-stage heat treatment at a temperature of 220 to 290°C to obtain a biaxially oriented film containing crystalline component B. As for the stretching method, sequential biaxial stretching (a stretching method that combines stretching in one direction at a time, such as stretching in the longitudinal direction followed by stretching in the width direction), simultaneous biaxial stretching (a method that stretches in the longitudinal and width directions simultaneously), or a method that combines these can be used. Here, sequential biaxial stretching, in which stretching is performed first in the longitudinal direction and then in the width direction, is given as an example.

[0061] The unstretched film is heated with a group of heating rolls and stretched in the longitudinal direction (MD direction) at a predetermined magnification in one or more stages (MD stretching). The longitudinal stretching magnification is preferably 1.5 times or more, more preferably 2.3 times or more, even more preferably 2.9 times or more, and particularly preferably 3.4 times or more, while it is preferably 5.0 times or less, and more preferably 4.5 times or less. The stretching temperature is preferably in the range of 80°C to 150°C. After that, it is cooled with a group of cooling rolls at 20 to 50°C. In the case of multi-stage stretching, the stretching magnification referred to here is the stretching magnification after all stretching is completed.

[0062] A common method for stretching in the width direction (TD direction) following MD stretching is, for example, the use of a tenter. Stretching in the width direction (TD stretching) is performed by gripping both ends of the uniaxially oriented film in the width direction with multiple clips, guiding it to a tenter, and widening the distance between opposing clips. The stretching temperature is preferably in the range of Tg to Tcc, more preferably (Tg+5) to (Tcc-10)°C. The stretching ratio in the width direction is preferably 2.0 times or more, more preferably 3.0 times or more, from the viewpoint of film flatness. On the other hand, it is preferably 5.0 times or less, and even more preferably 4.5 times or less.

[0063] Next, the stretched film is subjected to a heat-setting process under tension. A single or multi-stage heat treatment is performed at a temperature in the range of 220 to 280°C to obtain a biaxially oriented film containing crystalline component B. Then, the film is cooled to room temperature, and if necessary, relaxed in the longitudinal and widthwise directions, and wound up to obtain a wound body of biaxially oriented PAS film.

[0064] The winding is heated and aged at a temperature of 130°C to 205°C, preferably between 130°C and 205°C, more preferably between 140°C and 200°C, and even more preferably between 140°C and 175°C, for a period of 80 hours to 1000 hours, preferably between 100 hours and 1000 hours, and even more preferably between 100 hours and 160 hours, to form crystalline component A. This heating and aging may be performed on the capacitor form described later, instead of on the winding itself. Alternatively, it may be performed on a single-sheet biaxially oriented PAS film unwound from the winding.

[0065] Methods for forming resin layer A on one of the outermost layers of the biaxially oriented PPS film, with resin layer B being the resin layer, include coating the resin layer B with a solution or liquid raw material using a coater and then drying it, or vacuum depositing the resin layer A raw material onto resin layer B. When forming resin layer A by coating one side of resin layer B with the raw material, the coated surface of the PPS film that will become resin layer B may be subjected to a surface treatment such as corona discharge treatment beforehand. Performing a surface treatment such as corona discharge treatment improves the wettability of the coating composition for forming resin layer A onto the coated surface. As a result, the repulsion of the coating composition is suppressed, and it becomes easier to achieve a uniform coating thickness.

[0066] When forming resin layer A, it is preferable to crosslink the components of the coating composition for forming resin layer A. The method of crosslinking is not particularly limited, but examples include using a composition having multiple reaction sites as the coating composition for forming resin layer A and performing a crosslinking reaction by heat or ultraviolet light, or crosslinking by electron beam after coating the coating composition for forming resin layer A. Examples of compositions having multiple reaction sites include acrylates or urethane acrylates having two or more vinyl groups, epoxy having two or more epoxy groups, condensates of melamine and formaldehyde, mixtures of compounds having two or more isocyanate groups and compounds having three or more hydroxyl groups, and mixtures of compounds having two or more isocyanate groups and compounds having three or more amino groups.

[0067] In order to promote the crosslinking reaction, when forming the resin layer A, a catalyst such as an acid or a base, or an additive such as a cation initiator, an anion initiator, or a radical initiator may be added according to the reactivity of the reaction points. For example, when using an acrylate having two or more vinyl groups as a coating composition for forming the resin layer A, a coating liquid added with a radical initiator that generates radicals by ultraviolet rays is prepared, and after coating the coating liquid on the resin layer B, ultraviolet rays are irradiated to promote the crosslinking reaction. The radical initiator is not particularly limited, but a hydroxyalkylphenone type initiator, an aminoacetophenone type initiator, etc. that generate radicals by ultraviolet rays can be used. By forming a crosslinked structure in the resin layer A in this way, it becomes easy to improve the heat resistance of the PAS film of the present invention.

[0068] As an example, a method of forming the resin layer A by a bar coater will be described. First, a coating liquid is prepared by mixing 100 parts by mass of acrylate, 0.1 parts by mass to 5 parts by mass of α-hydroxyalkylphenone, and 800 parts by mass to 1000 parts by mass of 2-butanone. The coating liquid prepared so that the cured film thickness becomes 40 nm to 500 nm is coated on the corona-discharge-treated surface of the PPS film that will become the resin layer B with a bar coater. This is introduced into a drying oven at 80°C to 100°C and dried so that the drying time becomes 30 seconds to 2 minutes. Subsequently, it is introduced into a UV irradiation device, with an illuminance of 40 mW / cm 2 ~70 mW / cm 2 、an irradiation dose of 0.05 J / cm 2 ~0.3 J / cm 2 、and the coating film is cured under the conditions of an oxygen concentration of 800 ppm to 300 ppm to form the resin layer A, whereby the PAS film of the present invention can be obtained. Also, the PAS film of the present invention can be obtained by winding up the obtained PAS film.

[0069] The metal laminate of the present invention will now be described. From the viewpoint of integration, the metal laminate of the present invention has a metal layer on at least one surface of the PAS film of the present invention. Furthermore, for the purpose of enhancing self-healing properties, it is more preferable to have a metal laminate having resin layer B, resin layer A, and metal layer in this order. Here, "having resin layer B, resin layer A, and metal layer in this order" refers to all embodiments in which resin layer B, resin layer A, and metal layer are located in this order, and does not matter whether there are other layers between resin layer B and resin layer A, between resin layer A and metal layer, or outside resin layer B or metal layer.

[0070] The thickness of the metal layer is preferably in the range of 1 nm to 100 nm, more preferably 5 nm to 80 nm, and even more preferably 10 nm to 50 nm. The surface resistivity of the metal layer is preferably in the range of 0.1 Ω / sq to 10 Ω / sq, more preferably 2.0 Ω / sq to 8.0 Ω / sq, and even more preferably 3.0 Ω / sq to 6.0 Ω / sq. This is because a surface resistivity of 0.1 Ω / sq or higher improves self-healing properties. Conversely, keeping the surface resistivity of the metal layer below 10 Ω / sq reduces the deterioration of the dielectric loss tangent. The surface resistivity of the metal layer can be adjusted by adjusting the thickness of the metal layer.

[0071] The PAS film of the present invention exhibits excellent voltage resistance characteristics in high-temperature environments. Therefore, taking advantage of these characteristics, it can be suitably used as a film for film capacitors, and further suitable for use as an electrical insulating material for motors and transformers, circuit board material, lithium-ion battery material, fuel cell material, diaphragm, and the like. In particular, its high voltage resistance allows for miniaturization of products, and its excellent long-term stability enhances product reliability, making it suitable for use in inverters for mobility devices such as electric vehicles and electric aircraft, as well as film capacitors for generators.

[0072] The PAS film of the present invention is preferably used as a dielectric in film capacitors, but is not limited to the type of film capacitor. Specifically, in terms of electrode configuration, it may be either a foil-wound capacitor or a metal-deposited film capacitor, and is also preferably used in oil-immersion type capacitors impregnated with insulating oil or dry-type capacitors that do not use insulating oil at all. Furthermore, in terms of shape, it may be either a wound type or a laminated type. Among these, due to the characteristics of the PAS film of the present invention, it is preferable to use it as a metal-deposited film capacitor including a metal laminate. As a method for forming the metal layer, for example, vacuum deposition, sputtering, ion plating, plating, etc., can be used. Among these methods, vacuum deposition is preferred because it is superior in productivity. When the metal layer is deposited, oil deposition or tape deposition methods can be used. The deposition pattern of the metal layer is not particularly limited, but preferred patterns include, for example, T-margin patterns, honeycomb patterns, mosaic patterns, etc.

[0073] The metal component of the aforementioned metal layer is not particularly limited, but aluminum or an alloy of aluminum and zinc is preferably used. Alternatively, other metal components such as nickel, copper, gold, silver, or chromium can be deposited simultaneously or sequentially with aluminum to form the metal layer. A protective layer, such as oil, can also be provided on the deposited film. When laminating a metal layer onto a film consisting of resin layer A and resin layer B by vapor deposition, a surface treatment such as corona discharge may be performed on the deposition surface of the film capacitor before vapor deposition. Such surface treatment can improve the adhesion of the deposited metal to the surface.

[0074] Next, the film capacitor of the present invention will be described. The film capacitor of the present invention is made using the metal laminate of the present invention. The film capacitor of the present invention can be used as part of an automotive inverter and / or converter (for example, an inverter for a hybrid electric vehicle, a converter for a hybrid electric vehicle, an inverter for an electric vehicle, a converter for an electric vehicle, etc.).

[0075] The following describes the power control unit, electric vehicle, and electric aircraft of the present invention. The power control unit of the present invention has the film capacitor of the present invention. The power control unit is a system for managing power in electric vehicles, electric aircraft, and the like, which have mechanisms driven by electricity. By equipping the power control unit with the film capacitor of the present invention, it is possible to miniaturize the power control unit itself, improve its heat resistance and efficiency, and as a result, improve fuel efficiency.

[0076] The electric vehicle of the present invention is equipped with the power control unit of the present invention. Here, an electric vehicle refers to an automobile having a mechanism that is driven by electricity, such as an electric vehicle, hybrid vehicle, or fuel cell vehicle. As described above, the power control unit of the present invention can be miniaturized and also has excellent heat resistance and efficiency, so when an electric vehicle is equipped with the power control unit of the present invention, it leads to improved fuel efficiency and other benefits.

[0077] The electric aircraft of the present invention is equipped with the power control unit of the present invention. Here, an electric aircraft refers to an aircraft having an electric drive mechanism, such as a manned electric aircraft or a drone. As described above, the power control unit of the present invention can be miniaturized and also has excellent heat resistance and efficiency, so when an electric aircraft is equipped with the power control unit of the present invention, it leads to improved fuel efficiency and other benefits.

[0078] The manufacturing method for the film capacitor of the present invention will be described below. The manufacturing method for the film capacitor of the present invention is characterized by including the following steps 1 and 2. By manufacturing with these steps, it is possible to improve the voltage resistance and heat resistance when the capacitor is in use. Step 1: The metal laminate of the present invention is wound up to form a wound body. Step 2: The wound body is heat-treated at a temperature of 130°C to 210°C for 30 hours to 1000 hours. [Examples]

[0079] (1) Molecular weight, dw / dlog(M) The molecular weight of the PAS resin was calculated in polystyrene equivalent using gel permeation chromatography (GPC), a type of size exclusion chromatography (SEC). The GPC measurement equipment and conditions are shown below. Device: SSC-7110 manufactured by Senshu Science Co., Ltd. Columns: Showa Denko "Shodex" (registered trademark) UT-G + Shodex UT-806M x 2 Eluent: 1-Chloronaphthalene Detector: Differential refractive index detector Column temperature: 210℃ Pre-temperature bath temperature: 250℃ Pump constant temperature bath temperature: 50℃ Detector temperature: 210℃ Flow rate: 1.0mL / min Sample injection volume: 300μL (concentration: 0.1% by mass) Standard sample: Polystyrene.

[0080] dw / dlog(M) was obtained using the following method. First, the intensity detected by the detector was plotted on a curve (elution curve) with elution time on the x-axis and detection intensity on the y-axis, and a calibration curve of elution time and molecular weight was created using polystyrene as a standard sample. Using this calibration curve, the elution time for the sample was converted to the logarithm of molecular weight (log(M)) on the elution curve, and a molecular weight distribution curve was obtained with elution time on the x-axis and detection intensity on the y-axis. Next, an integral molecular weight distribution curve for log(M) was obtained, where the total area enclosed by the molecular weight distribution curve and the straight line (x-axis) where the intensity is 0 is set to 100%. Then, by differentiating this integral molecular weight distribution curve with respect to log(M), a graph of dw / dlog(M) for log(M) can be obtained (generally called a differential molecular weight distribution curve). The series of operations up to obtaining the differential molecular weight distribution curve was performed using the analysis software built into the GPC measuring instrument. The maximum value of dw / dlog(M) was read from the obtained differential molecular weight distribution curve. This measurement was repeated three times, and the average of the three maximum values ​​of dw / dlog(M) was recorded as the maximum value of dw / log(M) for the PAS-based resin.

[0081] (2) Film thickness A point was arbitrarily selected at the center of the film's width, and the thickness was measured at 30 locations at 5 cm intervals along the longitudinal direction from that point, using a contact-type electronic micrometer (K-312A) manufactured by Anritsu Corporation, under conditions of 23°C and 65% RH. The sample average of these 30 thicknesses was defined as the film thickness. The coefficient of variation of the film thickness was calculated according to the following formula. Coefficient of variation of thickness (%) = (Sample standard deviation of film thickness) / (Sample mean of film thickness) × 100 (3) Thickness of resin layer A, Thickness of resin layer B Using a microtome, ultrathin sections with a width-to-thickness cross-section of the film, each 5 mm wide, were prepared. These sections were then coated with platinum to create observation samples. Next, using a Hitachi S-4800 field emission differential electron microscope, the cross-sections were observed at an acceleration voltage of 1.0 kV, and the thicknesses of resin layer A and resin layer B were measured from arbitrary points in the observation image. The thicker of the two layers was designated as resin layer B, and the thinner layer as resin layer A, with an observation magnification of 10,000x. Furthermore, the same measurement was performed a total of 20 times, and the average values ​​were taken as the thicknesses of resin layer A and resin layer B, respectively.

[0082] (4) Melting point of crystalline components in PAS film In accordance with JIS K-7122 (1987), the following procedure was used to perform the measurement using a differential scanning calorimeter (Seiko Instruments EXSTAR DSC6220). First, a 5.0 mg PAS film was heated in a nitrogen atmosphere from 25°C to 350°C at a rate of 20°C / min, then held at 350°C for 5 minutes, and then rapidly cooled to below 25°C. The same measurement was performed for n=3 times, and the temperature of each endothermic peak obtained during the heating process was determined. For each endothermic peak temperature in the measurement with the fewest endothermic peaks, the endothermic peak temperature with the smallest difference from that peak temperature in the other two measurements was taken as the endothermic peak temperature originating from the corresponding crystalline component, and the average value obtained from the n=3 measurements was taken as the melting point of that crystalline component. For example, if endothermic peaks were observed in three measurements: 1st measurement: peak a) 170.1°C, peak b) 281.1°C; 2nd measurement: peak c) 169.5°C, peak d) 280.9°C; 3rd measurement: peak e) 170.2°C, peak f) 265.1°C, peak g) 281.0°C, the melting point of the first endothermic peak was calculated as 169.9°C by averaging peaks a), c), and e), and the melting point of the second endothermic peak was calculated as 280.0°C by averaging peaks b), d), and g). Peak f) was not used in the calculation.

[0083] (5) Number of endothermic peaks in PAS film In accordance with JIS K-7122 (1987), the following procedure was used to measure the endothermic properties of the PAS film using a differential scanning calorimeter (Seiko Instruments EXSTAR DSC6220). First, 5.0 mg of the PAS film was heated from 25°C to 350°C at a rate of 20°C / min in a nitrogen atmosphere, held at 350°C for 5 minutes, and then cooled from 350°C to below 25°C at a rate of 10°C / min. Next, the film was heated from 25°C to 350°C at a rate of 20°C / min and held at 350°C for 5 minutes. The number of endothermic peaks observed during each heating process was recorded. The same measurement was performed three times, and the average number of endothermic peaks observed during each heating process was taken as the number of endothermic peaks for each heating process.

[0084] (6) Longitudinal tanδ at 150°C Measurements were performed using the following apparatus and conditions. First, a rectangular PAS film sample (width (short side) 10 mm × length (long side) 20 mm), cut with the longitudinal direction as the long side, was attached to the apparatus chuck under a 23°C atmosphere and placed in the furnace. Then, the furnace was cooled with liquid nitrogen, and the sample was heated from -100°C to 180°C. A viscoelastic-temperature curve was drawn using the dynamic viscoelastic method, and the longitudinal tanδ at 150°C was read. Three measurements were performed, and the average value of the longitudinal tanδ at 150°C was calculated. The obtained value was adopted as the longitudinal tanδ of the PAS film at 150°C. <Equipment and Conditions> Device: EXSTAR DMS6100 (manufactured by Seiko Instruments Inc.) Test mode: Tensile mode Chuck spacing: 20mm Frequency: 10Hz Distortion amplitude: 10.0μm Gain: 1.5 Initial force amplitude: 400mN Temperature range: -100 to 180°C Heating rate: 5°C / min Measurement environment: Under air Measurement thickness: The film thickness specified in (1) above was used.

[0085] (7) Evaluation of film dielectric breakdown voltage at 150°C The film was heated for 1 minute in an oven maintained at 150°C, and then measured in that atmosphere according to JIS C2330(2001)7.4.11.2 Method B (flat electrode method). The dielectric breakdown voltage test (measured above) was performed 30 times, and the obtained values ​​were divided by the film thickness (measured in (2) above) to obtain a total of 30 measured values ​​(calculated values). Of these, the 5 values ​​in descending order of maximum value and the 5 values ​​in descending order of minimum value were excluded, and the withstand voltage values ​​of the lower 25% were determined and defined as the film dielectric breakdown voltage at 150°C. The film dielectric breakdown voltage at 150°C was evaluated as follows based on the obtained film dielectric breakdown voltage at 150°C. A: The film dielectric breakdown voltage at 150°C was 280V / μm or higher. B: The film dielectric breakdown voltage at 150°C was between 230V / μm and 280V / μm. C: The film dielectric breakdown voltage at 150°C was between 130V / μm and 230V / μm. D: The film dielectric breakdown voltage at 150°C was less than 130V / μm, or the film shrinkage was so large that evaluation was not possible.

[0086] (8) Evaluation of film capacitor characteristics (reliability at 150°C) Film winding inner surface: 25 W·min / m 2 Corona discharge treatment was performed in air at the specified treatment intensity. Next, aluminum was deposited on the corona discharge treated surface using a deposition pattern with a film resistance of 10Ω / sq and a margin portion perpendicular to the longitudinal direction, a so-called T-shaped margin (with a longitudinal pitch (period) of 17 mm and a fuse width of 0.5 mm due to masking oil) (a vacuum deposition machine manufactured by ULVAC, Inc. was used for deposition). Subsequently, the obtained deposition material was slit to obtain a deposition reel with a film width of 50 mm (end margin width of 2 mm). Next, film capacitor elements were wound using a component winding machine (KAW-4NHB) manufactured by Kaito Seisakusho Co., Ltd., subjected to metallizing treatment, and then heat-treated at 140°C for 5 hours under reduced pressure, to which lead wires were attached to finish the film capacitor elements. Ten of these film capacitor elements were subjected to a voltage of 800VDC at a high temperature of 150°C, and their capacitance was measured every 100 hours. For each film capacitor element, the time at which its capacitance fell below 90% of its initial value was identified, and the average value of this time was used as the lifespan of the film capacitor element. It was evaluated according to the following criteria: A means usable, B means poor practical performance, and C means unusable. The shape of the film capacitor element was observed visually. A: The lifespan was over 1000 hours, and there was no deformation of the film capacitor element. B: Although the lifespan was over 1000 hours, distortion was observed in the shape of the film capacitor element. C: The lifespan of the film capacitor element was less than 1000 hours.

[0087] [Raw materials, film] <Coating liquid for forming resin layer A> Urethane acrylate 1: Trade name "UV-3500BA", butyl acetate diluted product of urethane acrylate, manufactured by Mitsubishi Chemical Corporation 2-Butanone: Manufactured by Fuji Film Wako Pure Chemical Corporation Omnirad184: Manufactured by IGM Resins B.V., 1-hydroxycyclohexyl phenyl ketone.

[0088] <PPS resin> (Reference Example 1-1) In a 1-kiloliter stainless steel container equipped with a stirrer, 1 kilomol of 47% by mass sodium hydrosulfide aqueous solution, 1.02 kilomol of 47% by mass sodium hydroxide aqueous solution, 1.65 kilomol of N-methyl-2-pyrrolidone (NMP), 0.3 kilomol of sodium acetate, and 100 kilograms of deionized water were charged. The mixture was gradually heated to 235°C over approximately 180 minutes at atmospheric pressure while stirring at 240 rpm and passing nitrogen through it. After distilling off 209 kilograms of water and 0.4 kilograms of NMP, the reaction vessel was cooled to 160°C. The amount of hydrogen sulfide released was 0.02 kilomol. To the residual mixture, 0.003 kilomol of 1,2,4-trichlorobenzene, 1.02 kilomol of p-dichlorobenzene (p-DCB), and 1.35 kilomol of NMP were added. The reaction vessel was then sealed under nitrogen gas. The temperature was raised from 160°C to 270°C over 180 minutes while stirring at 400 rpm. The reaction was carried out at 270°C for 135 minutes, and then cooled from 270°C to 200°C over 100 minutes. Simultaneously with the start of cooling, 0.8 kilomol of water was added to the system over 10 minutes. After reaching 200°C, the system was rapidly cooled to near room temperature using a fan. The contents were removed, 1 kiloliter of NMP was added, and the mixture was stirred at 85°C for 30 minutes. The solvent and solids were then filtered through an 80-mesh sieve. The obtained solids were then mixed with 1 kiloliter of NMP, stirred at 85°C for 30 minutes, and filtered. The process of adding 1 kiloliter of warm water to the obtained solids, stirring at 70°C for 30 minutes, and filtering was repeated three times. The obtained solids were mixed with 1 kiloliter of warm water in a 0.005 wt% calcium acetate aqueous solution and stirred at 70°C for 30 minutes, and filtered. The obtained solid was mixed with 1 kiloliter of warm water and stirred at 70°C for 30 minutes, and the mixture was filtered. This process was repeated twice. The resulting solid was then dried under reduced pressure at 120°C for 5 hours to obtain a cross-linked PPS resin 1 with a melt flow rate (MFR) of 3 g / 10 min and a maximum dw / dlog(M) of 0.7.

[0089] (Reference example 2-1) A 1-liter SUS container equipped with a stirrer was charged with 1.01 kilomoles of a 47% by mass aqueous sodium hydrosulfide solution, 1.04 kilomoles of a 47% by mass aqueous sodium hydroxide solution, 1.6 kilomoles of N-methyl-2-pyrrolidone (NMP), 0.3 kilomoles of sodium acetate, and 100 kilograms of ion-exchanged water. While stirring at 240 rpm, nitrogen was passed through at atmospheric pressure, and the mixture was gradually heated to 235°C over about 180 minutes. After 209 kilograms of water and 0.4 kilograms of NMP were distilled off, the reaction vessel was cooled to 160°C. Also, the amount of hydrogen sulfide scattered was 0.02 kilomoles. To the residual mixture, 0.99 kilomoles of p-dichlorobenzene (p-DCB) and 2.40 kilomoles of NMP were added. Subsequently, the reaction vessel was sealed under nitrogen gas, and the temperature was raised from 160°C to 220°C over 90 minutes while stirring at 400 rpm, and the reaction was carried out at 220°C for 280 minutes. Then, the temperature was raised from 220°C to 250°C over 60 minutes, 0.8 kilomoles of water was injected into the system over 10 minutes, and the reaction was continued for 300 minutes. Thereafter, it was cooled from 255°C to 200°C over 100 minutes. After reaching 150°C, it was rapidly cooled to near room temperature using a blower. The contents were taken out, 1 liter of NMP was added, and it was stirred at 85°C for 30 minutes, and then the solvent and solids were separated by filtration through a sieve (80 mesh). To the obtained solids, 1 liter of NMP was added, and it was stirred at 85°C for 30 minutes and filtered. To the obtained solids, 1 liter of warm water was added, and it was stirred at 70°C for 30 minutes, and the filtration operation was repeated 3 times. To the obtained solids, 4.5 kilograms of calcium acetate monohydrate and 1 liter of an aqueous solution of warm water were added, and it was stirred at 70°C for 30 minutes and filtered. To the obtained solids, 1 liter of warm water was added, and it was stirred at 70°C for 30 minutes, and the filtration operation was repeated 2 times. The solids thus obtained were dried under reduced pressure at 120°C for 5 hours to obtain a PPS resin 2 with a melt flow rate (MFR) of 80 g / 10 min and a maximum value of dw / dlog(M) of 1.1.

[0090] <PPS pellets, PPS granules and particle master pellets> (Reference Example 1-2) The PPS resin 1 prepared in Reference Example 1-1 was fed into a vented, co-rotating twin-screw compounding extruder heated to 320°C, melted and extruded to produce strands, cooled with water at 25°C, and immediately cut to produce PPS pellets 1.

[0091] (Reference example 1-3) A particle masterbatch (MB1) with a particle content of 10% by mass was prepared in the same manner as in Reference Example 1-2, except that a mixture containing 90% by mass of PPS resin 1 prepared in Reference Example 1-1 and 10% by mass of calcium carbonate (average particle size 1.0 μm) as inert particles was melt-kneaded.

[0092] (Reference example 2-2) The PPS resin 2 prepared in Reference Example 2-1 was fed into a vented, co-rotating twin-screw compounding extruder heated to 320°C, melted and extruded to produce strands, cooled with water at 25°C, and immediately cut to produce PPS pellets 2.

[0093] (Reference example 2-3) A particle masterbatch (MB2) with a particle content of 10% by mass was prepared in the same manner as in Reference Example 2-2, except that a mixture of 90% by mass of PPS resin 1 prepared in Reference Example 2-1 and 10% by mass of calcium carbonate (average particle size 1.0 μm) as inert particles was melt-kneaded.

[0094] (Example 1) As raw materials for resin layer B, 99 parts by mass of PPS pellet 1 and 1 part by mass of MB1 were mixed and dried under reduced pressure at 180°C for 3 hours. The molten part was then supplied to a uniscrew extruder heated to 325°C. Next, the molten polymer was passed through a fiber-sintered stainless steel metal filter (20 μm cut) and extruded through a T-die set to 320°C. After that, it was cooled and solidified in close contact with a cast drum with a surface temperature of 25°C while applying an electrostatic charge, to obtain an unstretched film with a thickness of 50 μm. Next, the obtained unstretched film was stretched in the longitudinal direction of the film at a stretching temperature of 105°C at a magnification of 3.5 times using a longitudinal stretcher consisting of multiple heated roll groups, utilizing the difference in peripheral speed of the rolls. After that, both ends in the width direction of the obtained uniaxially oriented film were supported by multiple clips and guided to a tenter, where it was stretched in the width direction at a magnification of 3.3 times at a stretching temperature of 102°C. Subsequently, heat treatment was performed at 280°C, followed by a 2% relaxation treatment. After cooling to room temperature, the film edges were removed to obtain a 4.3 μm thick film (resin layer B). The obtained film roll was then heat-treated at a temperature of 150°C for 100 hours (offline heat treatment). After that, the side of resin layer B that was in contact with the cast drum was corona-treated, and a coating solution prepared by mixing urethane acrylate 1,2-butanone and "Omnirad" (registered trademark) 184 in a mass ratio of 100:900:0.3 was uniformly applied to the treated surface using a bar coater so that the thickness after curing would be the same as the thickness of resin layer A shown in Table 1 (50 nm). The film was then dried in a 90°C drying oven for 1 minute. Subsequently, the coated film was introduced into a UV irradiation device at an irradiance of 50 mW / cm². 2 , irradiation amount 0.1J / cm 2 The coating was cured under conditions of an oxygen concentration of 100 ppm to form resin layer A, and then the laminate of resin layer A and resin layer B was wound up to obtain a PAS film. The evaluation results are shown in Table 1.

[0095] (Examples 2-5, Comparative Examples 1-4) A film for a film capacitor was obtained in the same manner as in Example 1, except that the raw material formulations and film-forming conditions for resin layer A and resin layer B were as shown in Table 1. The evaluation results are shown in Table 1.

[0096] [Table 1]

[0097] Regarding Comparative Example 3, although it does not contain any crystalline component A based on melting point, it contains two crystalline components with different melting points. Therefore, the crystalline component with the relatively lower melting point is listed as crystalline component A. [Industrial applicability]

[0098] The polyarylene sulfide film of the present invention exhibits excellent dielectric strength in high-temperature environments. Therefore, by using it as a dielectric in film capacitors, the long-term stability of the film capacitors can be improved.

Claims

1. A polyarylene sulfide film characterized by containing crystalline component A having a melting point of 145°C or higher and 220°C or lower, and crystalline component B having a melting point higher than 220°C and 340°C or lower.

2. The polyarylene sulfide film according to claim 1, wherein, when the total heat of fusion of the crystalline components of the entire polyarylene sulfide film is taken as 100%, the heat of fusion of the crystalline component A is 0.01% or more and 49% or less.

3. The polyarylene sulfide film according to claim 1 or 2, wherein, when measuring the endothermic peaks of the polyarylene sulfide film, the number of endothermic peaks observed during the first heating process is greater than the number of endothermic peaks observed during the second heating process.

4. The polyarylene sulfide film according to claim 1 or 2, wherein the value of the longitudinal tanδ at 150°C, as measured by dynamic viscoelasticity measurement, is 0.001 or more and 0.15 or less.

5. The polyarylene sulfide film according to claim 1 or 2, wherein the coefficient of variation of the thickness when the thickness is measured at 30 points at 5 cm intervals in the longitudinal direction is 0% or more and 20% or less.

6. The polyarylene sulfide film according to claim 1 or 2, wherein, when the total mass of all components constituting the polyarylene sulfide film is taken as 100% by mass, more than 50% by mass and less than or equal to 100% by mass is polyphenylene sulfide.

7. The polyarylene sulfide film according to claim 1 or 2, having a resin layer A in at least one outermost layer that contains at least one resin selected from the group consisting of urethane acrylate polymer, acrylate polymer, urethane methacrylate polymer, methacrylate polymer, aliphatic polyether, aliphatic polyester, aliphatic polyamide, polyurethane, and polyurea.

8. A polyarylene sulfide film according to claim 1 or 2, which is a film for film capacitors.

9. A metal laminate having a metal layer on at least one surface of the polyarylene sulfide film according to claim 1 or 2.

10. A film capacitor comprising the metal laminate described in claim 9.

11. A power control unit having the film capacitor described in claim 10.

12. An electric vehicle having the power control unit described in claim 11.

13. An electric aircraft having the power control unit described in claim 11.

14. A method for manufacturing a film capacitor, comprising the following steps 1 and 2. Step 1: The metal laminate described in claim 9 is wound up to form a wound body. Step 2: The wound body is heat-treated at a temperature of 130°C to 205°C for 80 hours to 1000 hours.

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