Film for film capacitor, metal layer laminated film for film capacitor, and film capacitor

Abstract

To provide a film for a film capacitor which has high heat resistance and self healing property, and is also excellent in productivity.SOLUTION: A film for a film capacitor has a resin layer A having a melting point of 180°C or higher and / or a glass transition temperature of 130°C or higher, and a layer B thinner than the resin layer A on at least one film outermost layer, in which when coefficients of dynamic friction of the same surfaces in the two outermost layer surfaces are measured, when a surface having a larger coefficient of dynamic friction is represented by a-surface and a surface having a smaller coefficient of dynamic friction is represented by b-surface, and a coefficient of dynamic friction of the a-surfaces is represented by μdaa and a coefficient of dynamic friction of the a-surface and the b-surface is represented by μdab, the surfaces satisfy expressions of μdaa>μdab and μdab≤1.2, and at least one outermost layer surface satisfies a load area ratio Smr1≥12% that separates a projection crest part and a core part.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a film for a film capacitor serving as a dielectric of a film capacitor, a metal layer laminated film for a film capacitor, and a film capacitor.

Background Art

[0002] In recent years, due to global environmental problems and the like, the market for hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs) that use electric motors in combination, or electric vehicles (EVs) and fuel cell vehicles (FCVs) that are driven by electric motors has been expanding. Along with the expansion of the market for these motor-driven vehicles and motor-driven vehicles using electric motors in combination, the demand for film capacitors used in these vehicles is also rapidly increasing.

[0003] A film capacitor is a capacitor using a resin base film as a dielectric, and excellent frequency characteristics and temperature stability can be obtained. Examples of the base film of this film capacitor include polyester resin films such as polypropylene (PP) resin films, polyethylene terephthalate (PET) resin films, and polyethylene naphthalate (PEN) resin films, thermoplastic resin films such as polyphenylene sulfide (PPS) resin films, or polyetherimide (PEI) resin films which are amorphous thermoplastic resins.

[0004] Among these films, polyetherimide resin films have attracted attention as base films (Patent Document 1). This is because when a film capacitor is used for applications such as motor-driven vehicles and motor-driven vehicles using electric motors in combination, heat resistance capable of withstanding use in an environment of 120°C is required. However, if a base film made of polyetherimide resin with a glass transition temperature (Tg) of 200°C or higher is used, excellent electrical properties such as heat resistance, voltage resistance characteristics, and dielectric characteristics can be obtained.

[0005] On the one hand, base films with excellent heat resistance such as polyetherimide and polyphenylene sulfide generally have poor self-healing (SH) properties and have the drawback that the capacitor capacitance decreases when used for a long time. On the other hand, techniques for improving self-healing properties by providing a coating layer on the base film are known (Patent Documents 2 and 3).

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0007] However, in the prior art, when achieving both heat resistance and self-healing properties, a coating of polyparaxylylene resin, which is expensive, time-consuming to form, has poor productivity, and has a low effect of improving self-healing properties, is used, or a silicone-based self-healing coating that generates siloxane, which may cause conductor failure in an electric circuit during dielectric breakdown, is used. These are the problems. Therefore, in view of such a background of the prior art, the present invention aims to provide a film for a film capacitor that has high heat resistance and self-healing properties and is excellent in productivity.

Means for Solving the Problems

[0008] The above problems can be solved by the following invention.

[0009] The film for a film capacitor of the present invention has a resin layer A with a melting point of 180°C or higher and / or a glass transition temperature of 130°C or higher, and a layer B with a thickness thinner than that of the resin layer A on at least one of the outermost film layers. Among the two outermost layer surfaces, when the coefficient of kinetic friction is measured between the same surfaces, the surface with the larger coefficient of kinetic friction is defined as the a-surface, and the surface with the smaller coefficient of kinetic friction is defined as the b-surface. When the coefficient of kinetic friction between the a-surfaces is μdaa and the coefficient of kinetic friction between the a-surface and the b-surface is μdab, μdaa > μdab and μdab ≤ 1.2 are satisfied, and at least one of the outermost layer surfaces satisfies a load area ratio Smr1 ≥ 12% for separating the protruding peak portion and the core portion. It is a film for a film capacitor.

Effect of the Invention

[0010] According to the present invention, it is possible to provide a film for a film capacitor that has high heat resistance and self-healing properties and is also excellent in productivity.

Embodiments for Carrying Out the Invention

[0011] The film for a film capacitor of the present invention has a resin layer A with a melting point of 180°C or higher and / or a glass transition temperature of 130°C or higher, and a layer B with a thickness thinner than that of the resin layer A on at least one of the outermost film layers. Among the two outermost layer surfaces, when the coefficient of kinetic friction is measured between the same surfaces, the surface with the larger coefficient of kinetic friction is defined as the a-surface, and the surface with the smaller coefficient of kinetic friction is defined as the b-surface. When the coefficient of kinetic friction between the a-surfaces is μdaa and the coefficient of kinetic friction between the a-surface and the b-surface is μdab, μdaa > μdab and μdab ≤ 1.2 are satisfied, and at least one of the outermost layer surfaces satisfies a load area ratio Smr1 ≥ 12% for separating the protruding peak portion and the core portion. Hereinafter, the film for a film capacitor of the present invention will be specifically described.

[0012] The film for a film capacitor of the present invention has a resin layer A having a melting point of 180°C or higher and / or a glass transition temperature of 130°C or higher. The lower limit of the melting point of the resin layer A is preferably 205°C, more preferably 215°C, and the upper limit is not particularly provided, but is preferably 400°C, more preferably 350°C. The lower limit of the glass transition temperature of the resin layer A is preferably 180°C, more preferably 205°C, and the upper limit is not particularly provided, but is preferably 400°C, more preferably 350°C. By including the melting point and / or the glass transition temperature of the resin layer A within the above-described range, it becomes difficult to cause insulation failure due to heat shrinkage or film breakage when using the film for a film capacitor in a high-temperature environment of 120°C or higher.

[0013] The thickness of the resin layer A of the present invention is not particularly limited, but is preferably 100 μm or less, and more preferably 10 μm or less. By setting the thickness of the resin layer A of the present invention to 100 μm or less, it becomes easy to reduce the volume when forming a capacitor element. The lower limit of the thickness of the resin layer A is not particularly limited, but is preferably 0.50 μm, more preferably 1.3 μm, and even more preferably 1.6 μm. By setting the thickness of the resin layer A to 0.50 μm or more, it becomes easy to increase the breakdown voltage.

[0014] The raw materials used for the resin layer A of the film for the film capacitor of the present invention are not particularly limited. For example, polyolefin resins such as polystyrene (PS) resin, polymethylpentene (PMP) resin, cyclic olefin (COP) resin, and cyclic olefin copolymer (COC) resin; polyester resins such as polyethylene terephthalate (PET) resin, polybutylene terephthalate (PBT) resin, and polyethylene naphthalate (PEN) resin; polyamide resins such as polyamide 6 (PA6) resin, polyamide 66 (PA66) resin, polyamide 46 (PA46) resin, polyamide 4T (PA4T) resin, polyamide 6T (PA6T) resin, modified polyamide 6T (modified PA6T) resin, polyamide 9T (PA9T) resin, polyamide 10T (PA10T) resin, and polyamide 11T (PA11T) resin; polysulfone resins such as polysulfone (PSU) resin, polyether sulfone (PES) resin, and polyphenyl sulfone (PPSU) resin; polyarylene sulfide resins such as polyphenylene sulfide (PPS) resin, polyphenylene sulfide ketone resin, polyphenylene sulfide sulfone resin, and polyphenylene sulfide ketone sulfone resin; polyimide (PI) resins such as polyimide (PI) resin, polyether imide (PEI) resin, and polyamide imide (PAI) resin; polyaryl ether ketone resins such as polyether ketone (PEK) resin, polyether ether ketone (PEEK) resin, polyether ketone ketone (PEKK) resin, polyether ether ketone ketone (PEEKK) resin, and polyether ketone ether ketone ketone (PEKEKK) resin; polytetrafluoroethylene (PTFE) resin (also referred to as tetrafluoroethylene resin), polytetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA) resin (also referred to as tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer resin), tetrafluoroethylene-hexafluoropropylene copolymer (FEP) resin (also referred to as tetrafluoroethylene-hexafluoropropylene copolymer resin), tetrafluoroethylene-ethylene copolymer (ETFE) resin (also referred to as tetrafluoroethylene-ethylene copolymer resin), and polychlorotrifluoroethylene (PCTFE) resin (also referred to as chlorotrifluoroethylene resin).Examples include polyvinylidene fluoride (PVDF) resin (also referred to as vinylidene fluoride resin), fluororesins such as vinylidene fluoride - tetrafluoroethylene - hexafluoropropylene copolymer resin, polyacetal resin, liquid crystal polymer (LCP) resin, polycarbonate (PC) resin, polyarylate (PAR) resin, phenol resin, polyurea resin, melamine resin, epoxy resin, alkyd resin, etc. Among these, polyetherimide resin, polycarbonate resin, polyphenylene sulfide resin, polyethersulfone resin, and polysulfone resins such as polyphenylsulfone resin, polyimide resin, polymethylpentene resin, polyetheretherketone resin, polyetherketoneketone resin, polyaryletherketone resin, which are excellent in heat resistance at 150°C, are preferably used. Among the resins with excellent heat resistance, polyphenylene sulfide resin, polyetherimide resin, polyphenylsulfone resin, and polyethersulfone resin, which have a low dielectric loss tangent and are suitable for use as a capacitor, are more preferably used. It is more preferable to contain at least one of these resins in an amount of 50% by mass or more and 100% by mass or less. These resins can also use modified products, derivatives, and copolymers with other compounds. They may be used alone or mixed in two or more types.

[0015] In the resin layer A of the film for a film capacitor of the present invention, within a range that does not impair its properties, it may contain an antioxidant, a light stabilizer, an ultraviolet absorber, a plasticizer, a lubricant, a crosslinking agent, a flame retardant, an antistatic agent, a heat resistance improver, a colorant, a slip agent, an antiblocking agent, inorganic particles, resin particles, inorganic compounds, organic compounds, etc. In addition, these components can be used alone or in combination of multiple types as necessary.

[0016] The film for a film capacitor of the present invention has a layer B having a thickness smaller than that of the resin layer A on at least one outermost layer of the film. The oxygen atom content of the layer B is preferably 1.0% by mass or more. The oxygen atom content of the layer B is more preferably 1.5% by mass or more, still more preferably 21% by mass or more, and particularly preferably 25% by mass or more. The upper limit of the oxygen atom content of the layer B is not particularly limited, but is preferably 50% by mass, more preferably 37% by mass, and still more preferably 34% by mass. By setting the content of oxygen atoms contained in the layer B to 1.0% by mass or more, the layer B is likely to volatilize during dielectric breakdown, and the self-healing property can be enhanced. By setting the content of oxygen atoms contained in the layer B to 50% by mass or less, the blocking property between the films is low, and a film excellent in productivity can be obtained. The fact that the oxygen atom content of the layer B is 1.0% by mass or more means that when the total of hydrogen atoms, carbon atoms, sulfur atoms, silicon atoms, nitrogen atoms, and oxygen atoms in the layer B is 100% by mass, the oxygen atoms in the layer B are 1.0% by mass or more. The content of silicon atoms Si in the layer B described later can be interpreted in the same manner.

[0017] The thickness of the layer B of the present invention is not particularly limited, but is preferably 10 nm or more, and more preferably 50 nm or more. By setting the thickness of the layer B to 10 nm or more, it becomes easy to enhance the self-healing property. The upper limit of the thickness of the layer B is not particularly limited, but is preferably 5.0 μm, more preferably 1.0 μm, still more preferably 0.50 μm, and particularly preferably 0.30 μm. By setting the thickness of the layer B to 5.0 μm or less, it becomes easy to increase the dielectric breakdown voltage.

[0018] Here, the thickness of each layer can be measured by observing the width-direction - thickness-direction cross-section with a field emission scanning electron microscope and using its length measurement function. The detailed procedure will be described later. Also, the atomic content in each layer can be determined from the atomic fractions obtained by Rutherford backscattering / forward hydrogen scattering analysis simultaneous measurement method (Pelletron 3SDH manufactured by National Electrostatics Corporation). The detailed procedure will be described later (the same applies to the other atomic contents in each layer as well as the oxygen atom content in layer B).

[0019] The content of silicon atom Si in layer B is preferably 27% by mass or less. The upper limit of the content of silicon atom Si in layer B is more preferably 15% by mass or less, still more preferably 3.0% by mass or less, and even more preferably 1.0% by mass or less. It is particularly preferable that layer B does not contain silicon atom Si. By setting the content of silicon atom Si contained in layer B to 27% by mass or less, the deterioration of capacitor characteristics due to siloxane generated during dielectric breakdown can be suppressed.

[0020] Layer B preferably satisfies the following condition (i). Condition (i): The value XB calculated based on the following formula (a) from the atomic fractions of hydrogen atom H, carbon atom C, sulfur atom S, silicon atom Si, nitrogen atom N, and oxygen atom O contained in layer B is 0.90 or less. Formula (a) XB = (atomic fraction of carbon atom C in layer B + atomic fraction of nitrogen atom N in layer B + atomic fraction of sulfur atom S in layer B + atomic fraction of silicon atom Si in layer B) / (atomic fraction of hydrogen atom H in layer B + atomic fraction of oxygen atom O in layer B) The upper limit of XB in the above condition (i) is more preferably 0.80, still more preferably 0.70, and particularly preferably 0.65. XB is the ratio of atoms that tend not to evaporate easily during dielectric breakdown and atoms that tend to evaporate easily. By setting it to 0.90 or less, it becomes easier to improve the self-healing property and the reliability of the capacitor. The lower limit of XB is not particularly limited, but is preferably 0.050, more preferably 0.20. By setting XB to 0.050 or more, it becomes easier to improve the adhesion between layer B and resin layer A.

[0021] The raw materials used for layer B are not particularly limited. For example, resins and low-molecular organic compounds can be used. From the perspective of adhesion to resin layer A, it is preferable to use a resin. The resin used for layer B is not particularly limited. For example, polyolefin resins such as polystyrene (PS) resin, polymethylpentene (PMP) resin, cyclic olefin (COP) resin, and cyclic olefin copolymer (COC) resin; polyester resins such as polyethylene terephthalate (PET) resin, polybutylene terephthalate (PBT) resin, and polyethylene naphthalate (PEN) resin; polyamide resins such as polyamide 6 (PA6) resin, polyamide 66 (PA66) resin, polyamide 46 (PA46) resin, polyamide 4T (PA4T) resin, polyamide 6T (PA6T) resin, modified polyamide 6T (modified PA6T) resin, polyamide 9T (PA9T) resin, polyamide 10T (PA10T) resin, and polyamide 11T (PA11T) resin; polysulfone resins such as polyether sulfone (PES) resin and polyphenyl sulfone (PPSU) resin; polyarylene sulfide resins such as polyphenylene sulfide (PPS) resin, polyphenylene sulfide ketone resin, polyphenylene sulfide sulfone resin, and polyphenylene sulfide ketone sulfone resin; polyimide (PI) resins such as polyimide (PI) resin, polyether imide (PEI) resin, and polyamide imide (PAI) resin; polyaryl ether ketone resins such as polyether ketone (PEK) resin, polyether ether ketone (PEEK) resin, polyether ketone ketone (PEKK) resin, polyether ether ketone ketone (PEEKK) resin, and polyether ketone ether ketone ketone (PEKEKK) resin; polytetrafluoroethylene (PTFE) resin (also called tetrafluoroethylene resin), polytetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA) resin (also called tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer resin), tetrafluoroethylene-hexafluoropropylene copolymer (FEP) resin (also called tetrafluoroethylene-hexafluoropropylene copolymer resin), tetrafluoroethylene-ethylene copolymer (ETFE) resin (also called tetrafluoroethylene-ethylene copolymer resin).Polychlorotrifluoroethylene (PCTFE) resin (also referred to as chlorotrifluoroethylene resin), polyvinylidene fluoride (PVDF) resin (also referred to as vinylidene fluoride resin), fluororesins such as vinylidene fluoride - tetrafluoroethylene - hexafluoropropylene copolymer resin, polyacetal resin, liquid crystal polymer (LCP) resin, polycarbonate (PC) resin, polyarylate (PAR) resin, phenol resin, polyurethane resin, melamine resin, epoxy resin, alkyd resin, acrylic resin, polymethyl methacrylate resin (PMMA), polyurethane resin (PU), polyurethane acrylate resin, cellulose, cellulose derivatives (for example, cellulose acetate, carboxymethyl cellulose, hydroxyethyl cellulose, hydroxypropyl methyl cellulose, etc.), petroleum resin, terpene resin, terpene phenol resin, etc. can be mentioned. Among these resins, as resins with a low XB value and high self - healing property, polyolefin resins such as polyethylene (PE) resin, polypropylene (PP) resin, polystyrene (PS) resin, polymethylpentene (PNP) resin, cyclic olefin (COP) resin, and cyclic olefin copolymer (COC) resin, polyester resins such as polyethylene terephthalate (PET) resin, polybutylene terephthalate (PBT) resin, and polyethylene naphthalate (PEN) resin, epoxy resin, alkyd resin, acrylic resin, polymethyl methacrylate resin (PMMA), polyacetal resin, liquid crystal polymer (LCP) resin, polycarbonate (PC) resin, polyarylate (PAR) resin, phenol resin, cellulose, cellulose derivatives (for example, cellulose acetate, carboxymethyl cellulose, hydroxyethyl cellulose, hydroxypropyl methyl cellulose, etc.), petroleum resin, terpene resin, terpene phenol resin are preferably used.,

[0022] Among these raw materials, the acrylic resin can enhance its heat resistance through crosslinking during formation, and the epoxy resin and cellulose derivatives have high heat resistance due to their main chain structures. By using them as the raw materials for layer B, when manufacturing a capacitor element using the capacitor film of the present invention, it becomes easy to extend the lifespan at high temperatures. Also, since acrylic resin, epoxy resin, cellulose derivatives, and polyester resin are resins containing oxygen atoms, it becomes easy to increase the oxygen atom content in layer B and enhance the self-healing property. From these aspects, it is more preferable that layer B contains at least one of acrylic resin, epoxy resin, cellulose derivatives, and polyester resin in an amount of 50% by mass or more and 100% by mass or less. These raw materials can also be used in the form of modified products, derivatives, copolymers with other compounds, or resins formed by polymerizing after coating in the form of monomers. They can be used alone or in combination of two or more kinds.

[0023] From the perspective of increasing the height of the protruding peak portion on the surface of the layer B side and improving the slipperiness, the film for a film capacitor of the present invention preferably has layer B containing two or more components that are mutually incompatible. Here, the "mutually incompatible components" refer to two components that are not uniformly mixed at the molecular level. Specifically, it refers to these two components when phases mainly composed of different two components both form a phase structure of 0.01 μm or more (whether it corresponds to the "main component" here can be determined by whether the total content of the two components exceeds 50% by mass in all the components constituting layer B). For example, when layer B contains three or more components, if a phase mainly composed of a certain component forms a phase structure of 0.01 μm or more, it is considered to satisfy "containing two or more mutually incompatible components". When the components constituting layer B are three or more, if two of them satisfy the above requirements, regardless of whether the remaining other components satisfy the above requirements, it is regarded as "containing two or more mutually incompatible components".

[0024] Whether two or more components are incompatible can be determined by, for example, an electron microscope, a differential scanning calorimeter (DSC), and various other methods as described in Polymer Alloys and Blends, Leszek A Utracki, hanser Publishers, Munich Viema New York, P64. The method of mixing two or more incompatible components with each other to increase the height of the protrusion is not particularly limited. For example, a method of dispersing particles and a resin in a solvent and leaving the particles as protrusions during drying, a method of mixing a resin with high affinity and a resin with low affinity for the material of resin layer A so that the resin with low affinity is dotted as protrusions on the surface of layer B side, and a method of dissolving resins having high affinity for their respective solvents in two solvents with different boiling points and setting the temperature so that one solvent evaporates first during drying, and the resin dissolved in the remaining solvent precipitates as protrusions later, and a method combining these can be mentioned.

[0025] As a combination of two incompatible components used for layer B, a combination of an acrylic resin and a cellulose derivative, a combination of a cellulose derivative and an epoxy resin, and a combination of a methacrylic resin and an acrylic resin are preferable. These can also use modified products, derivatives, copolymers with other compounds, and resins formed by polymerizing after coating in the form of monomers. When forming the composition for forming layer B by coating it on resin layer A, for the combination of these raw materials, it is preferable to coat a coating solution in which one is in the form of a polymer and the other is in the form of a monomer, and then polymerize the monomer to form. Also, if importance is attached to processability, for example, a combination of an epoxy resin and silica is also preferable.

[0026] From the perspective of increasing the lifespan when used in a capacitor, the film for a film capacitor of the present invention preferably has a dissipation factor of 2.0% or less. From the above perspective, the upper limit of the dissipation factor of the film for a film capacitor is preferably 0.70%, more preferably 0.40%, and even more preferably 0.30%. When the dissipation factor of the film for a film capacitor is 2.0% or less, the amount of heat generated during energization is reduced when used in a film capacitor, and the lifespan of the film capacitor is prolonged. The lower limit of the dissipation factor of the film for a film capacitor is not particularly limited, but is preferably 0.0010% and more preferably 0.010%. The dissipation factor of the film for a film capacitor can be decreased by using a resin with low polarity as the resin of resin layer A, or by reducing the thickness of layer B when using a raw material with a higher dissipation factor than resin layer A as the raw material of layer B. Here, the dissipation factor refers to the value measured according to JIS C2138-2007, and the detailed measurement method will be described later.

[0027] For the film for a film capacitor of the present invention, among the two outermost layer surfaces, when measuring the coefficient of kinetic friction between the same surfaces, the surface with the larger coefficient of kinetic friction is defined as surface a, and the surface with the smaller coefficient of kinetic friction is defined as surface b. When the coefficient of kinetic friction between surface a and surface a is μdaa, and the coefficient of kinetic friction between surface a and surface b is μdab, μdaa > μdab and μdab ≤ 1.2 are satisfied. Also, the coefficient of kinetic friction between surface b and surface b is defined as μdbb. μdab more preferably satisfies μdab ≤ 0.90, even more preferably μdab ≤ 0.75, and particularly preferably μdab ≤ 0.60. By setting μdaa > μdab and μdab ≤ 1.2, it is difficult to degrade the capacitor characteristics and the slipperiness can be improved. Furthermore, by setting μdab to a low value, the processability can be further improved. The lower limit of μdab is not particularly limited, but is preferably 0.10. By setting μdab to 0.10 or more, it becomes easier to prevent the film for a film capacitor of the present invention from slipping when it is formed into a wound body. The coefficient of kinetic friction is measured according to JIS K 7125 (1999) under a load of 200 g, at 25°C, and 65% RH, and the detailed procedure will be described later.

[0028] As a method for making μdaa and μdab satisfy μdaa > μdab and μdab ≤ 1.2, although not particularly limited, there is a method of forming the resin layer A on a smooth base film or a mirror roll, and forming the layer B thereon so as to contain two incompatible components as raw materials. When μdab is high, μdab can be lowered by adjusting the mixing ratio so that the difference in the content of the two components described above becomes small. Further, in order to make μdaa ≤ μdab, μdab can be lowered by the method described above, or the smoothness of the base film or roll used to form the resin layer A can be increased to increase μdaa so that μdaa > μdab.

[0029] The value of μdbb is not particularly limited, but is preferably 0.10 or more, and more preferably 0.25 or more. By making μdbb 0.10 or more, it becomes easy to suppress the deviation when the film for a film capacitor of the present invention is made into a wound body. The upper limit of μdbb is not particularly limited, but is preferably 2.0, more preferably 1.5, and even more preferably 1.2. By making μdbb 2.0 or less, it becomes easy to improve the workability.

[0030] The value of μdaa is not particularly limited, but is preferably 0.10 or more, and more preferably 0.25 or more. By making μdaa 0.10 or more, it becomes easy to suppress the deviation when the film for a film capacitor of the present invention is made into a wound body. The upper limit of μdaa is not particularly limited, but is preferably 2.0, more preferably 1.5, and even more preferably 1.2. By making the value of μdaa 2.0 or less, it becomes easy to improve the workability.

[0031] The film for a film capacitor of the present invention satisfies Smr1 ≥ 12% on at least one outermost layer surface, where Smr1 is the load area ratio that separates the protruding peak portion from the core portion. Since Smr1 focuses on the ratio of the protruding portions, the higher its value, the more effectively the contact area when contacting other surfaces can be reduced. By setting Smr1 to 12% or more, the slipperiness of the film can be improved while keeping the breakdown voltage of the film high. The upper limit of Smr1 is not particularly limited, but it is preferably 49%, more preferably 18%. By setting Smr1 to 49% or less, when the film for a film capacitor of the present invention is made into a wound body, it becomes easier to suppress deformation of the film surface. Note that Smr1 can be measured and calculated in accordance with ISO 25178-2:2012 and ISO 25178-3:2012, and the detailed measurement procedure will be described later.

[0032] The method for making Smr1 on at least one outermost layer surface satisfy Smr1 ≥ 12% is not particularly limited. For example, a method of forming layer B by including two incompatible components in the raw materials can be mentioned. When Smr1 is low, Smr1 can be increased by adjusting the mixing ratio so that the difference in the content of the two components described above becomes large, or by making the solubility parameters (so-called SP values) of the two components small.

[0033] The value XA calculated based on the following formula (b) from the atomic fractions of hydrogen atom H, carbon atom C, sulfur atom S, silicon atom Si, nitrogen atom N, and oxygen atom O contained in resin layer A preferably satisfies XA > XB with respect to XB. Formula (b) XA = (atomic fraction of carbon atom C in resin layer A + atomic fraction of nitrogen atom N in resin layer A + atomic fraction of sulfur atom S in resin layer A + atomic fraction of silicon atom Si in resin layer A) / (atomic fraction of hydrogen atom H in resin layer A + atomic fraction of oxygen atom O in resin layer A) Since the higher XA is, the more likely the resin has a structure with a high degree of unsaturation and a rigid structure, by making XA > XB satisfied, it becomes easier to enhance the self-healing property while maintaining high heat resistance.

[0034] The ratio of the peak height Spk-a of the protruding mountain portion on the a surface to the peak height Spk-b of the protruding mountain portion on the b surface satisfies Spk-b / Spk-a ≥ 2.0, and preferably the load area ratio Smr1-b for separating the protruding mountain portion on the b surface from the core portion is Smr1-b ≥ 12%. By setting Smr1-b to 12% or more, the slipperiness of the film can be improved. The upper limit of Smr1-b is not particularly limited, but it is preferably 49%. By setting Smr1-b to 49% or less, when the film for a film capacitor of the present invention is formed into a wound body, it becomes easy to suppress deformation of the film surface. By satisfying Spk-b / Spk-a ≥ 2.0 and Smr1-b ≥ 12%, it becomes easy to obtain a film having excellent slipperiness. Note that Spk-a and Spk-b can be measured and calculated in accordance with ISO 25178-2:2012 and ISO 25178-3:2012, and detailed measurement procedures will be described later.

[0035] As a method for making Spk-a, Spk-b, and Smr1-b on at least one outermost layer surface satisfy Spk-b / Spk-a ≥ 2.0 and Smr1-b ≥ 12%, although not particularly limited, for example, a method of forming layer B by including two incompatible components as raw materials can be mentioned. When Spk-b / Spk-a is low, the difference in the content of the two components described above can be increased, and Spk-b / Spk-a can be increased by making the solubility parameters (so-called SP values) of the two components large. When Smr1-b is low, the mixing ratio can be adjusted so that the difference in the content of the two components described above becomes large, or Smr1-b can be increased by making the solubility parameters (so-called SP values) of the two components small.

[0036] When the total thickness of the resin layer A and the layer B is T(F), it is preferable that the maximum valley depth Sv of both outermost layer surfaces of the film for a film capacitor of the present invention satisfies Sv / T(F) < 0.30 for both. The upper limit of Sv / T(F) is preferably 0.20 for both sides. That is, it is more preferable that Sv / T(F) ≤ 0.20. Sv / T(F) means the size of the dent with respect to the thickness of the film, and the higher it is, the easier it is to cause dielectric breakdown when compared at the same thickness. By setting Sv / T(F) to less than 0.30, it becomes easy to obtain a film having high withstand voltage characteristics. Note that Sv can be measured and calculated in accordance with ISO 25178-2:2012 and ISO 25178-3:2012, and the detailed measurement procedure will be described later.

[0037] The method for making Sv / T(F) less than 0.30 is not particularly limited. For example, there is a method of forming the resin layer A on a smooth base film or a mirror surface roll, coating the raw material of the solution or liquid layer B thereon with a coater, and then drying to form the layer B. When Sv / T(F) of the surface on the layer B side becomes 0.30 or more, Sv / T(F) can be lowered by adding a leveling agent to the raw material of the layer B.

[0038] The value of the maximum valley depth Sv of both outermost layer surfaces of the film for a film capacitor of the present invention is preferably 0.10 nm or more, and more preferably 10 nm or more for any surface. By setting the maximum valley depth Sv of both outermost layer surfaces of the film for a film capacitor of the present invention to 0.10 nm or more for any surface, it becomes easy to improve the processability. The upper limit of the maximum valley depth Sv of both outermost layer surfaces of the film for a film capacitor of the present invention is preferably 5000 nm for any surface. By setting the maximum valley depth Sv of both outermost layer surfaces of the film for a film capacitor of the present invention to 5000 nm or less for any surface, it becomes easy to obtain a film having high withstand voltage characteristics.

[0039] Hereinafter, the metal layer laminated film for a film capacitor of the present invention will be described. The film for a film capacitor of the present invention is preferably a metal layer laminated film for a film capacitor having a metal layer on the surface of at least one outermost layer from the viewpoint of integration. For the purpose of enhancing the self-healing property, it is more preferable to use a metal layer laminated film for a film capacitor having a resin layer A, a layer B, and a metal layer in this order. Here, "having a resin layer A, a layer B, and a metal layer in this order" means all aspects in which the resin layer A, the layer B, and the metal layer are located in this order, and it does not matter whether there are other layers between the resin layer A and the layer B and between the layer B and the metal layer.

[0040] Furthermore, in the metal layer laminated film for a film capacitor of the present invention, in order to maintain high withstand voltage characteristics by enhancing the smoothness of the resin layer A made of a resin with high heat resistance and to exhibit the effect of improving the slipperiness by the layer B, the layer B is provided only on one surface of the resin layer A, the metal layer is provided on the layer B side, and when the surface with a larger coefficient of kinetic friction measured between the same surfaces among the two outermost layer surfaces is defined as the a surface and the surface with a smaller coefficient of kinetic friction is defined as the b surface, it is particularly preferable that the b surface is on the layer B side when viewed from the resin layer A.

[0041] The thickness of the metal layer is preferably in the range of 1 nm or more and 100 nm or less, more preferably 5 nm or more and 80 nm or less, and even more preferably 10 nm or more and 50 nm or less. Also, the surface resistance value of the metal layer is preferably in the range of 0.1 Ω / sq or more and 10 Ω / sq or less, more preferably 2 Ω / sq or more and 8 Ω / sq or less, and even more preferably 3 Ω / sq or more and 6 Ω / sq or less. This is because when the surface resistance value of the metal layer is less than 0.1 Ω / sq, the self-healing property (also referred to as self-repairing property) deteriorates, which is not preferable. Conversely, when it exceeds 10 Ω / sq, it is based on the reason that the dielectric loss tangent may deteriorate.

[0042] The film for a film capacitor of the present invention is preferably used as a dielectric film for a capacitor, but is not limited to the type of capacitor. Specifically, from the perspective of the electrode structure, it may be either a foil-wound capacitor or a metal vapor deposition film capacitor, and is also preferably used for an oil-impregnated type capacitor impregnated with insulating oil or a dry-type capacitor that does not use insulating oil at all. Also, from the perspective of the shape, it may be a wound type or a laminated type. Among these, due to the characteristics of the film of the present invention, it is preferably used as a metal vapor deposition film capacitor including a metal layer laminated film. As a method for forming the metal layer, for example, a vacuum evaporation method, a sputtering method, an ion plating method, a plating method, etc. are used. Among these methods, the vacuum evaporation method, which is excellent in productivity, is preferred. When the metal layer is vapor-deposited, an oil method, a tape, etc. are used as the vapor deposition method. The vapor deposition pattern of the metal layer is not particularly limited, but preferred patterns include, for example, a T margin pattern, a honeycomb pattern, a mosaic pattern, etc.

[0043] Next, the film capacitor of the present invention will be described. The film capacitor of the present invention is formed using the metal layer laminated film for a film capacitor of the present invention. The film capacitor of the present invention can be a part of an inverter and / or converter for an automobile (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.).

[0044] Next, an example of a method for manufacturing the film for a film capacitor of the present invention will be described. Note that the following example has a two-layer structure having a resin layer A and a layer B, but the film for a film capacitor of the present invention may have a two-layer structure as long as it has a resin layer A and a layer B, or may have a structure of three or more layers having other layers. In the case of a structure of three or more layers, the resin layer A is the layer with the largest thickness and has a melting point of 180°C or higher and / or a glass transition temperature of 130°C or higher.

[0045] First, as a method for forming the resin layer A, a method of supplying the raw material of the resin layer A to an extruder, melt-extruding it from a slit-shaped die such as a T-die, and solidifying it on a cooling drum or the like to form the resin layer A, or a method of coating a solution or liquid raw material of the resin layer A on a base film such as a polyolefin film, a polyethylene terephthalate film, a polyimide film, or a film obtained by applying a silicone coat to these to enhance releasability with a coater and then drying to form the resin layer A, or a method of casting the liquid on a casting belt and then drying to form the resin layer A, etc. may be mentioned. Among these, from the viewpoint of enhancing the smoothness of the resin layer A, a method of forming the resin layer A by coating a solution or liquid raw material of the resin layer A on a base film with a coater and then drying, or a method of supplying the raw material to an extruder, melt-extruding it from a slit-shaped die such as a T-die, solidifying it on a cooling drum or the like to form it into a film shape, and then stretching it uniaxially or biaxially to use it as the resin layer A is preferably performed by either method. When the resin layer A is formed on the base film, the resin layer A may or may not be peeled off from the base film before forming the layer B, but from the viewpoint of enhancing transportability, it is preferable to form the layer B without peeling.

[0046] As a method for forming the layer B on one surface of the resin layer A, a method of coating a solution or liquid raw material of the layer B on the resin layer A with a coater and then drying, or a method of vacuum-depositing the raw material of the layer B on the resin layer A may be mentioned. From the viewpoint of increasing the protrusion height of the formed layer B, it is preferable to form it by a method of coating a solution or liquid raw material of the layer B on the resin layer A with a coater and then drying.

[0047] When forming by applying the raw material of layer B onto one surface of resin layer A, a surface treatment such as corona discharge treatment may be performed in advance on the coating surface of resin layer A. By performing a surface treatment such as corona discharge treatment, the wettability to the coating surface of the paint composition can be improved, the repellency of the paint composition can be prevented, and it becomes easy to achieve a uniform coating thickness. When laminating a metal layer on the film composed of the obtained resin layer A and layer B, the method is not particularly limited, but it is preferable to deposit the metal on layer B by vacuum evaporation. Aluminum is preferable as the metal used for evaporation. At this time, other metal components such as nickel, copper, gold, silver, chromium, and zinc can also be deposited simultaneously or sequentially with aluminum. When laminating the metal layer on the film composed of resin layer A and layer B by evaporation, a surface treatment such as corona discharge treatment may be performed on the evaporation surface of the film before evaporation. By performing a surface treatment such as corona discharge treatment, the adhesion of the deposited metal to the film can be enhanced.

[0048] When forming layer B, it is preferable to crosslink the components of layer B. The method of crosslinking is not particularly limited, and examples include using a compound having a plurality of reactive points as a raw material for layer B and causing a crosslinking reaction by heat or ultraviolet rays. Examples of the compound having a plurality of reactive points include acrylates having two or more vinyl groups, epoxies having two or more epoxy groups, and condensates of melamine and formaldehyde. Among these, from the viewpoint of increasing the oxygen concentration of layer B and enhancing the self-healing property, it is preferable to use an acrylate having two or more vinyl groups. In order to promote the crosslinking reaction, 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 reactive points when forming layer B. For example, when using an acrylate having two or more vinyl groups as a raw material for layer B, a coating solution added with a radical initiator that generates radicals by ultraviolet rays is prepared, and after coating the coating solution on resin layer A, ultraviolet rays are irradiated to promote the crosslinking reaction. The radical initiator is not particularly limited, but a hydroxyalkylphenone type initiator or an aminoacetophenone type initiator that generates radicals by ultraviolet rays can be used. By crosslinking layer B, it becomes easy to enhance the heat resistance of the film for film capacitors of the present invention.

Example

[0049] Hereinafter, the film for film capacitors of the present invention will be specifically described using examples. However, Example 9 below is regarded as a reference example. The measurement method of the characteristic values and the evaluation method of the effects are as follows.

[0050] (1) Film thickness T(F) The thicknesses of any 10 locations of the film were measured using a contact-type electronic micrometer (K-312A type) manufactured by Anritsu Corporation at 23°C and 65% RH. The arithmetic average value of the thicknesses of those 10 locations was defined as the film thickness T(F).

[0051] (2) Thickness T(A) of resin layer A and thickness T(B) of layer B Using the microtome method, an ultra-thin section with a width of 5 mm and having a cross-section in the width direction - thickness direction of the film was prepared, and the cross-section was platinum-coated to obtain an observation sample. Next, using a field emission scanning electron microscope (S-4800) manufactured by Hitachi, Ltd., the film cross-section was observed at an acceleration voltage of 1.0 kV, and the thickness of resin layer A and the thickness of layer B were measured from an arbitrary location of the observation image. Note that the thicker layer of the two layers was defined as resin layer A, the thinner layer was defined as layer B, and the observation magnification was 10,000 times. Furthermore, the same measurement was performed a total of 20 times, and the average values were used as the thickness T(A) of resin layer A and the thickness T(B) of layer B.

[0052] (3) Melting point and glass transition temperature of resin layer A (2) Weighed 5 mg of resin layer A determined by the procedure described in (2), and using a differential scanning calorimeter (EXSTAR DSC6220 manufactured by Seiko Instruments Inc.), it was heated and cooled according to the following program in a nitrogen atmosphere. <Program> Step 1: Heated from 25°C to 330°C at 10°C / min, and then maintained at 330°C for 5 minutes. Step 2: Cooled from 330°C to 25°C at -10°C / min, and then maintained at 25°C for 5 minutes. Step 3: Heated from 25°C to 330°C at 10°C / min, and then maintained at 330°C for 5 minutes. In the temperature rising process of Step 3, when looking at the DSC chart from 330°C towards the low temperature side, the maximum value of the temperature at which the slope of the DSC chart changes from the slope of the baseline was defined as T_1, and the minimum value of the temperature at which the slope of the DSC chart returns to the slope of the baseline at a temperature lower than T_1 was defined as T_2. The value Tg obtained by the following calculation formula was defined as the glass transition temperature of resin layer A. <Calculation formula> Tg = (T_1 + T_2) / 2.

[0053] Also, the peak temperature of the endothermic curve obtained in Step 3 was taken as the melting point of Resin Layer A. When multiple peak temperatures could be observed, the highest temperature was taken as the melting point of Resin Layer A. However, when no peak was observed in the endothermic curve obtained in Step 3 and, when looking at the DSC chart from 330°C towards the lower temperature side during the temperature increase process in Step 3, the slope of the DSC chart did not change from the slope of the baseline in the region of 25°C or more, both the melting point and the glass transition temperature of Resin Layer A were set to 330°C or more. When no peak was observed in the endothermic curve obtained in Step 3 but the glass transition temperature was less than 330°C, it was considered to have no melting point. When, during the temperature increase process in Step 3, when looking at the DSC chart from 330°C towards the lower temperature side, the slope of the DSC chart did not change from the slope of the baseline in the region of 25°C or more but the melting point was less than 330°C, it was considered to have no glass transition temperature. In each corresponding case, it was described as "-" in Tables 1 to 3.

[0054] (4) The atomic fractions of hydrogen atom H, carbon atom C, sulfur atom S, silicon atom Si, nitrogen atom N, and oxygen atom O contained in Resin Layer A and Layer B, and the contents of oxygen atom O and silicon atom Si in Layer B The surface on the Resin Layer A side of the film was analyzed by Rutherford backscattering / hydrogen forward scattering analysis simultaneous measurement method (Pelletron 3SDH manufactured by National Electrostatics Corporation), and the atomic yields Y(H), Y(C), Y(S), Y(Si), Y(N), and Y(O) of hydrogen atom H, carbon atom C, sulfur atom S, silicon atom Si, nitrogen atom N, and oxygen atom O in Resin Layer A were obtained. From the obtained values, the values obtained based on the following formula were taken as the atomic fractions of hydrogen atom H, carbon atom C, sulfur atom S, silicon atom Si, nitrogen atom N, and oxygen atom O contained in Resin Layer A. <Calculation formula> Let Y(All) = Y(C) + Y(S) + Y(Si) + Y(N) + Y(O) + Y(H). Atomic fraction of hydrogen atom H = Y(H) / Y(All) Atomic fraction of carbon atom C = Y(C) / Y(All) Atomic fraction of sulfur atom S = Y(S) / Y(All) Atomic fraction of silicon atom Si = Y(Si) / Y(All) Atomic fraction of nitrogen atom N = Y(N) / Y(All) Atomic fraction of oxygen atom O = Y(O) / Y(All).

[0055] Regarding layer B as well, analysis and calculation of each value were performed in the same procedure except that the surface analyzed by the Rutherford backscattering / hydrogen forward scattering analysis simultaneous measurement method was the surface on the layer B side, and the atomic fractions of hydrogen atom H, carbon atom C, sulfur atom S, silicon atom Si, nitrogen atom N, and oxygen atom O contained in layer B were determined. Also, the contents of oxygen atom O and silicon atom Si in layer B were calculated based on the following formula. Note that the atomic fractions Y(C), Y(S), Y(Si), Y(N), Y(O), and Y(H) in the formula are all those of layer B. <Calculation formula> Content of oxygen atom O (mass%) = 100×16.0×Y(O) / (12.0×Y(C)+32.1×Y(S)+28.1×Y(Si)+14.0×Y(N)+16.0×Y(O)+1.01×Y(H)) Content of silicon atom Si (mass%) = 100×28.1×Y(Si) / (12.0×Y(C)+32.1×Y(S)+28.1×Y(Si)+14.0×Y(N)+16.0×Y(O)+1.01×Y(H)) Note that the measurement conditions are as follows. Incident ion: 4 He ++ Incident energy: 2300 keV Incident angle: 75 deg Scattering angle: 160 deg Recoil angle: 30 deg Sample current: 4 nA Beam diameter: 2 mm φ In-plane rotation: None Irradiation dose: 0.5 μC × 20 points (5) XA, XB Using each value obtained by the method described in (4), XB was calculated by the following formula (a), and XA was calculated by the following formula (b). Formula (a): XB = (atomic fraction of carbon atom C in layer B + atomic fraction of nitrogen atom N in layer B + atomic fraction of sulfur atom S in layer B + atomic fraction of silicon atom Si in layer B) / (atomic fraction of hydrogen atom H in layer B + atomic fraction of oxygen atom O in layer B) Formula (b): XA = (atomic fraction of carbon atom C in resin layer A + atomic fraction of nitrogen atom N in resin layer A + atomic fraction of sulfur atom S in resin layer A + atomic fraction of silicon atom Si in resin layer A) / (atomic fraction of hydrogen atom H in resin layer A + atomic fraction of oxygen atom O in resin layer A).

[0056] (6) Coefficient of dynamic friction (μdaa, μdab, μdbb) Using a slip tester manufactured by Toyo Seiki Co., Ltd., in accordance with JIS K 7125 (1999), the coefficient of dynamic friction was measured at a load of 200 g, 25 °C, and 65% RH. When one surface of the film was designated as the α surface and the other surface as the β surface, the measurement was carried out for two cases: when the α surfaces were overlapped and when the β surfaces were overlapped. The measurement was performed three times for each case, and the average value of the obtained values was calculated and taken as the coefficient of dynamic friction when the surfaces were measured against each other. When the coefficient of dynamic friction measured when the surfaces of the α surface and the β surface were overlapped with each other was larger for one surface, that surface was designated as the a surface, and when it was smaller for the other surface, that surface was designated as the b surface. The coefficient of dynamic friction between the a surfaces was designated as μdaa, and the coefficient of dynamic friction between the b surfaces was designated as μdbb. Furthermore, the measurement was carried out three times for the case where the a surface and the b surface were overlapped, and the average value of the obtained values was calculated and taken as μdab. When the frictional force detected by the load cell during the measurement exceeded 5.9 N for each case, the measurement was interrupted, and the measured value of the coefficient of dynamic friction for that case was set to > 3.0. When the coefficient of dynamic friction measured when the same surfaces were measured against each other was equal or > 3.0, the surface with the higher arithmetic mean roughness Sa measured by the method described below was designated as the b surface.

[0057] (7) Arithmetic mean roughness Sa, load area ratio Smr1, protrusion height Spk, maximum valley depth Sv Each parameter was measured and calculated in accordance with ISO 25178-2:2012 and ISO 25178-3:2012. However, the measurement was performed using a scanning white light interferometer "VS1540" (manufactured by Hitachi High-Technologies Corporation, and the measurement conditions and apparatus configuration will be described later). The captured image was subjected to complementary processing (complete complement) using the attached analysis software, surface correction was performed by fourth-order polynomial approximation, and then processed with a median filter (3×3 pixels) for measurement. Also, the S-Filter Nesting Index of the S-filter was set to 0.455. The measurement was performed on both sides of a film cut into a 5 cm × 5 cm square shape. The intersection of the diagonals was set as the first measurement point (starting point), and positions 1 cm away from the starting point towards each of the four corners were set as the 2nd to 5th measurement points, respectively, for a total of five measurement positions. Measurements were taken at each measurement position, and Sa, Smr1, Spk, and Sv at each measurement position were obtained according to the above procedure. The average values were adopted as Sa, Smr1, Spk, and Sv of the film. In particular, the value of Spk on side a was designated as Spk-a, and the values of Spk and Smr1 on side b were designated as Spk-b and Smr1-b, respectively. From the obtained values of Spk-a and Spk-b, Spk-b / Spk-a was calculated. From the obtained Sv values of each side and the above-mentioned value of T(F), Sv / T(F) was calculated. <Measurement Conditions and Apparatus Configuration> Objective lens: 10x Eyepiece tube: 1x Zoom lens: 1x Wavelength filter: 530 nm white Measurement mode: Wave Measurement software: VS-Measure 10.0.4.0 Analysis software: VS-Viewer10.0.3.0 Measurement area: 561.1 μm × 561.5 μm Number of pixels: 1,024 × 1,024.

[0058] (8) SH Defect Rate, Self-Healing Property Corona discharge treatment was performed in the atmosphere on the surface of layer B side with a treatment intensity of 25 W·min / m 2 For films without layer B, 25 W·min / m was applied to side b2 Corona discharge treatment was carried out in the atmosphere at the treatment intensity of -3 Pa. Subsequently, commercially available aluminum was vapor-deposited on the corona discharge treatment surface with a bell jar type vacuum evaporation apparatus at a pressure of 1.0×10

[0059] A 10 cm square "Teflon" (registered trademark) sheet with a thickness of 1 mm was placed on a 1 m×2 m copper plate. On the "Teflon" (registered trademark) sheet, the short side of the test piece was parallel to one side of the "Teflon" (registered trademark) sheet, and the test piece was placed such that a region 1 cm from the end on one short side of the test piece was on the "Teflon" (registered trademark) sheet. The part of the test piece on the "Teflon" (registered trademark) sheet was sandwiched by about 2 cm 2 and a 5 cm square plate-shaped conductive rubber electrode was placed on the "Teflon" (registered trademark) sheet. Further, a 3 cmφ cylindrical electrode was placed on the rubber electrode so that the center of gravity came above the region where the rubber electrode, the test piece, and the "Teflon" (registered trademark) sheet overlapped. A DC power supply was connected to the cylindrical electrode and the copper plate via wires respectively, a voltage of 100 VDC was applied as the initial voltage, and after 15 seconds at this voltage, a so-called step-up test was performed in which the applied voltage was gradually increased stepwise to the initial voltage +800 VDC at 100 VDC / 30 seconds, and a plurality of insulation breakdown marks were generated on the metal layer laminated film.

[0060] The generated insulation breakdown marks were visually observed. One insulation breakdown mark where two or more insulation breakdown marks overlapped was regarded as one SH defective portion, and an insulation breakdown mark where this was not the case was regarded as one normal portion, and the respective numbers were obtained, and the SH defect rate was obtained by the following formula. The same measurement was performed twice, and the average value was adopted as the SH defect rate of the film. In the case where no insulation breakdown occurred, the same measurement was performed with the initial voltage set to 900 VDC. In the case where no insulation breakdown occurred even at an initial voltage of 10,000 VDC, the SH defect rate was set to 0%. <Calculation formula> SH defect rate (%) = 100 × (number of SH defective parts) / (number of normal parts + number of SH defective parts) Based on the SH defect rate of the film, the self-healing property was evaluated as follows. S: The SH defect rate is 16% or less. A: The SH defect rate is greater than 16% and 22% or less. B: The SH defect rate is greater than 22% and 30% or less. C: The SH defect rate is greater than 30%.

[0061] (9) Evaluation of processability Corona discharge treatment was performed in the air on the surface of side B of the layer at a treatment intensity of 25 W·min / m 2 For the film without layer B, corona discharge treatment was performed in the air on surface b at a treatment intensity of 25 W·min / m 2 Next, on the corona discharge treated surface, commercially available aluminum was vapor-deposited with a bell jar type vacuum vapor deposition apparatus at a pressure of 1.0 × 10 -3 Pa and a filament voltage of 2.6 kV to form a 50 nm vapor-deposited film, and a metal layer laminated film was obtained. The obtained metal layer laminated film was cut into a rectangular shape of 12 cm × 7.5 cm with the longitudinal direction as the long side to obtain a test piece. Using a slip tester manufactured by Toyo Seiki Co., Ltd., in accordance with JIS K 7125 (1999), the coefficient of kinetic friction between the metal vapor-deposited surface and the surface without metal vapor deposition of the obtained metal layer laminated film was measured three times at a load of 200 g, 25 °C, and 65% RH, and the average value of the obtained values was taken as the coefficient of kinetic friction μM of the metal laminated film. When the frictional force detected by the load cell exceeded 5.9 N during the measurement, the measurement was interrupted, and in that case, the measured value of μM was set to > 3.0. Based on the obtained μM, the processability of the film was determined according to the following criteria. S: μM is 0.60 or less. A: μM is greater than 0.60 and 0.90 or less. B: μM is greater than 0.90 and 1.5 or less. C: μM is greater than 1.5.

[0062] (10) Dielectric loss tangent In accordance with JIS C2138-2007, the dielectric loss tangent was measured. First, the film was cut into a square shape of 6 cm × 6 cm, and corona discharge treatment was performed in the air at a treatment intensity of 25 W·min / m 2 on the surface of the B layer side. For the film without the B layer, corona discharge treatment was performed in the air at a treatment intensity of 25 W·min / m 2 on the b surface. Next, commercially available aluminum was vapor-deposited on the corona discharge-treated surface with a Berger-type vacuum evaporation device at a pressure of 1.0×10 -3 Pa and a filament voltage of 2.6 kV to form a circular thin-film electrode with a diameter of 5.0 cm and a thickness of 50 nm. Subsequently, on the surface of the film where corona discharge treatment was not performed, commercially available aluminum was vapor-deposited with a Berger-type vacuum evaporation device at a pressure of 1.0×10 -3 Pa and a filament voltage of 2.6 kV so that the center position coincides with the center of the electrode formed on the corona discharge-treated surface, to form a circular thin-film electrode with a diameter of 5.6 cm and a thickness of 50 nm, and a test piece was obtained. The obtained test piece was measured for the dielectric loss tangent with an E4980A Precision LCR Meter (manufactured by Keysight Technologies) by the contact method at 23°C, a relative humidity of 50%, a frequency of 10 kHz, and n = 5, and the average value of the obtained values was taken as the dielectric loss tangent of the film.

[0063] (11) Evaluation of the film insulation breakdown voltage at 150°C After heating the film in an oven maintained at 150°C for 1 minute, it was measured in that atmosphere in accordance with JIS C2330 (2001) 7.4.11.2 Method B (flat-plate electrode method). However, for the lower electrode, a sheet of "Conductive Rubber E-100<65>" manufactured by Tokawa Rubber Co., Ltd. with the same dimensions was placed on the metal plate described in Method B of JIS C2330 (2001) 7.4.11.2 and used. The insulation breakdown voltage test (the above measurement) was performed 30 times, and the obtained values were divided by the thickness of the film (measured in the above (1)) and converted to (V / μm). Among the 30 measured values (calculated values) obtained, the average value of 20 points excluding 5 points in descending order from the maximum value and 5 points in ascending order from the minimum value was obtained, and this was taken as the film insulation breakdown voltage at 150°C. Based on the obtained film insulation breakdown voltage at 150°C, the evaluation of the film insulation breakdown voltage at 150°C was performed as follows. S: The film dielectric breakdown voltage at 150 °C was 270 V / μm or higher. A: The film dielectric breakdown voltage at 150 °C was 240 V / μm or higher and less than 270 V / μm. B: The film dielectric breakdown voltage at 150 °C was 210 V / μm or higher and less than 240 V / μm. C: The film dielectric breakdown voltage at 150 °C was 100 V / μm or higher and less than 210 V / μm. D: The film dielectric breakdown voltage at 150 °C was less than 100 V / μm or the film shrinkage was large and the evaluation was impossible.

[0064] (12) Evaluation of film capacitor characteristics (reliability at 150 °C) Corona discharge treatment was performed in the air on the surface of the B side of the film at a treatment intensity of 25 W·min / m 2 For films without layer B, corona discharge treatment was performed in the air on the b surface at a treatment intensity of 25 W·min / m 2 Next, on the corona discharge treatment surface, aluminum was deposited with a vacuum deposition machine manufactured by ULVAC, Inc. in a so-called T-shaped margin (the longitudinal pitch (period) was 17 mm and the fuse width was 0.5 mm) with a margin provided in the direction perpendicular to the longitudinal direction with a film resistance of 10 Ω / sq. After slitting, a deposited reel with a film width of 50 mm (end margin width: 2 mm) was obtained. Next, using this reel, a film capacitor element was wound with an element winding machine (KAW-4NHB) manufactured by Kaito Seisakusho Co., Ltd. After applying metallicon, heat treatment was performed at a temperature of 130 °C for 8 hours under reduced pressure, and lead wires were attached to finish the film capacitor element. Using 10 of the capacitor elements thus obtained, a so-called step-up test was performed in which a voltage of 250 VDC was applied to the capacitor element at a high temperature of 150 °C, and after 10 minutes had elapsed at this voltage, the applied voltage was gradually increased stepwise at 50 VDC / min. After increasing the voltage until the capacitance decreased to 12% or less of the initial value, the capacitor element was disassembled and the state of destruction was examined, and the film capacitor characteristics were evaluated as follows. S: There was no change in the shape of the film capacitor element and no through-breakdown was observed. A: There was no change in the shape of the film capacitor element, and a through-break within 5 layers of the film was observed. B: There was no change in the shape of the film capacitor element, and a through-break penetrating 5 to 7 layers of the film was observed. C: A change was observed in the shape of the film capacitor element or a through-break penetrating 7 to 14 layers of the film was observed. D: The shape of the film capacitor element changed greatly and was damaged, or the processability of the film was poor, and the film capacitor element could not be fabricated. -: The evaluation of the film capacitor characteristics was not performed. S can be used without problems, A can be used depending on the conditions, B is usable although inferior in practical performance, C is usable although inferior in practical performance depending on the conditions. D is difficult to use as a film for a practical capacitor.

[0065] 〔Resin, Film, Coating Liquid〕 Polyphenylene sulfide resin particles 1 (PPS particles 1): A 1-liter autoclave equipped with an engineering stirrer was charged with 1.00 mol of 47% by mass sodium hydrosulfide, 1.02 mol of 96% by mass sodium hydroxide, 1.56 mol of N-methyl-2-pyrrolidone (NMP), 0.46 mol of sodium acetate, and 140 g of ion-exchanged water. While stirring at 250 rpm, nitrogen was passed through at normal pressure and gradually heated to 225°C over about 3 hours. After 212 g of water and 4 g of NMP were distilled off, the reaction vessel was cooled to 160°C. Next, 1.00 mol of p-dichlorobenzene (p-DCB) and 1.32 mol of NMP were added, and the reaction vessel was sealed under nitrogen gas. Then, while stirring at 240 rpm, the temperature was raised from 200°C to 235°C at a rate of 0.6°C / min. After reaching 235°C, the reaction was continued at 235°C for 95 minutes. Then, the temperature was raised to 270°C at a rate of 0.8°C / min and held for 100 minutes. At this time, after reaching 270°C, 1 mol of water was injected into the system over 15 minutes. After holding at 270°C for 100 minutes, it was cooled to 200°C at a rate of 1.0°C / min, and then cooled to near room temperature by pouring room temperature cooling water into the autoclave. Subsequently, the contents were taken out, diluted with 0.4 liters of NMP, stirred at 85°C for 30 minutes, and then the solvent and solids were separated by filtration through a sieve (80 mesh). Further, 0.5 liters of NMP was added to the obtained solids, stirred at 85°C for 30 minutes, and the solids were separated by filtration. Then, the obtained solids were washed three times with 0.9 liters of warm water and separated by filtration. 1 liter of warm water was added to the particles (solids) thus obtained, washed twice, separated by filtration to obtain polymer particles. After drying with hot air at 80°C, it was dried under reduced pressure at 120°C to obtain granules of polyphenylene sulfide (PPS) resin (PPS granule 1) with a melting point of 280°C and a weight average molecular weight of 70,000.

[0066] PPS raw material 1 for film (PPS1): PPS granule 1 was put into a vented co-rotating twin-screw kneading extruder (manufactured by Nippon Steel Works, screw diameter 30 mm, screw length / screw diameter = 45.5) heated to 320°C, melt-extruded at a residence time of 90 seconds and a screw rotation speed of 150 revolutions / min to be discharged in a strand shape, and cooled with water at a temperature of 25°C. Then, it was immediately cut to produce chips, which were used as PPS raw material 1 for film (PPS1).

[0067] PPS raw material for film (PPS2): 100 parts by mass of PPS granules 1, 0.05 parts by mass of calcium carbonate particles 1 with an average particle size of 0.7 μm (“NITOREX” #30PS manufactured by Nitto Funka Kogyo Co., Ltd.), and 0.2 parts by mass of calcium stearate were mixed, and the resulting mixed powder was pelletized to prepare resin pellets mainly composed of PPS. The obtained resin pellets were put into a vented co-rotating twin-screw kneading extruder (manufactured by Nippon Steel Works, screw diameter 30 mm, screw length / screw diameter = 45.5) heated to 320 °C, melt-extruded at a residence time of 90 seconds and a screw rotation speed of 150 revolutions per minute, discharged in a strand shape, and cooled with water at a temperature of 25 °C. Then, it was immediately cut to produce chips, which were used as the PPS raw material 2 (PPS2) for the film.

[0068] PPS film 1: As the raw material, PPS1 was vacuum-dried at 180 °C for 3 hours. Then, it was supplied to an extruder, melted at a temperature of 320 °C under a nitrogen atmosphere, and introduced into a T-die head. Then, it was extruded in a sheet shape from the T-die head to form a melt single-layer sheet, which was discharged onto a casting drum with a surface temperature maintained at 25 °C and a rotation speed of 4.0 m / min, and adhered by the electrostatic printing method and cooled and solidified to be cast, obtaining an unstretched film. The obtained unstretched film was stretched in the longitudinal direction of the film at a stretching temperature of 103 °C with a magnification of 3.1 times using a longitudinal stretching machine composed of a plurality of heated roll groups, utilizing the peripheral speed difference of the rolls. Then, both end portions in the width direction of the obtained uniaxially stretched film were supported by clips and led to a tenter, and stretched in the width direction at a stretching temperature of 100 °C with a magnification of 3.3 times. Subsequently, after heat treatment at 280 °C, 2% relaxation treatment was performed, and it was cooled to room temperature. Then, corona discharge treatment was performed on the film surface (the side in contact with the casting drum) in the atmosphere with a treatment intensity of 25 W·min / m 2 to obtain a biaxially stretched PPS film with a thickness of 4.5 μm after removing the film edge.

[0069] PPS film 2: A biaxially oriented PPS film with a thickness of 4.6 μm was obtained in the same manner as PPS film 1, except that PPS2 was used instead of PPS1 as the raw material.

[0070] PPS film 3: A biaxially oriented PPS film with a thickness of 6.0 μm was obtained in the same manner as PPS film 1, except that the speed of the casting drum was set to 3.0 m / min.

[0071] Coating solution 1: A coating solution prepared by mixing 70 g of acrylate (I) (trade name “Biscoat” #300, condensate of pentaerythritol and acrylic acid, containing 45% by mass of pentaerythritol tetraacrylate and 35% by mass of pentaerythritol triacrylate, manufactured by Osaka Organic Chemical Industry Co., Ltd.), 50 g of cellulose acetate (i) (manufactured by Fujifilm Wako Pure Chemical Corporation, degree of acetylation 54%), 880 g of 2-butanone (manufactured by Fujifilm Wako Pure Chemical Corporation), and 200 mg of Omnirad 184 (manufactured by IGM Resins B.V., 1-hydroxycyclohexyl phenyl ketone).

[0072] Coating solution 2: A coating solution prepared by mixing 70 g of acrylate (II) (trade name “EBECRYL” (registered trademark) 150, manufactured by Daicel Ornex Co., Ltd., ethylene oxide-modified bisphenol A diacrylate), 30 g of cellulose acetate (i), 900 g of 2-butanone (manufactured by Fujifilm Wako Pure Chemical Corporation), and 200 mg of Omnirad 184 (manufactured by IGM Resins B.V., 1-hydroxycyclohexyl phenyl ketone).

[0073] Coating solution 3: A coating solution prepared by mixing 80 g of acrylate (I), 11 g of an epoxy resin (trade name "EPICLON" (registered trademark) 850, active group equivalent 189 eq / g, manufactured by DIC Corporation), 9.0 g of an active ester (trade name "HPC-8000-65T", active group equivalent 223 eq / g, manufactured by DIC Corporation), 900 g of 2-butanone (manufactured by Fujifilm Wako Pure Chemical Corporation), 200 mg of Omnirad 184 (manufactured by IGM Resins B.V., 1-hydroxycyclohexyl phenyl ketone), and 10 mg of 4-dimethylaminopyridine (manufactured by Tokyo Chemical Industry Co., Ltd.).

[0074] Coating solution 4: A coating solution prepared by mixing 65 g of acrylate (I), 35 g of a terpene phenol resin (trade name "TH130", manufactured by Yasuhara Chemical Co., Ltd.), 900 g of 2-butanone (manufactured by Fujifilm Wako Pure Chemical Corporation), and 200 mg of Omnirad 184 (manufactured by IGM Resins B.V., 1-hydroxycyclohexyl phenyl ketone).

[0075] Coating solution 5: A coating solution prepared by mixing 99.9 g of nitrile butadiene rubber (trade name "Nipol" (registered trademark) DN003, manufactured by Zeon Corporation, Mooney viscosity 77.5), 100 mg of calcium carbonate particles 2 (trade name "CALUCEO P015S0", particle diameter 150 nm), and 900 g of 2-butanone (manufactured by Fujifilm Wako Pure Chemical Corporation).

[0076] Coating solution 6: A coating solution prepared by mixing 54 g of an epoxy resin (trade name "EPICLON" (registered trademark) 850, active group equivalent 189 eq / g, manufactured by DIC Corporation), 45.5 g of an active ester (trade name "HPC-8000-65T", active group equivalent 223 eq / g, manufactured by DIC Corporation), 7.0 g of silica particles (y) (average particle diameter 0.1 μm, "Seephoster" (registered trademark) KE-P10, manufactured by Nippon Shokubai Co., Ltd.), 900 g of 2-butanone (manufactured by Fujifilm Wako Pure Chemical Corporation), and 10 mg of 4-dimethylaminopyridine (manufactured by Tokyo Chemical Industry Co., Ltd.).

[0077] Coating liquid 7: A coating liquid prepared by mixing 93 g of polyetherimide (trade name "ULTEM" (registered trademark) Resin 1010, manufactured by SABIC, glass transition temperature 217°C), 7.0 g of silica particles (y) (average particle diameter 0.1 μm, "Sea Hostar" (registered trademark) KE-P10, manufactured by Nippon Shokubai Co., Ltd.), and 900 g of N-methylpyrrolidone (manufactured by Fujifilm Wako Pure Chemical Corporation).

[0078] (Example 1) 15 g of polyetherimide resin (trade name "ULTEM" (registered trademark) Resin 1010, manufactured by SABIC, glass transition temperature 217°C) was dissolved in 85 g of N-methyl-2-pyrrolidone (manufactured by Fujifilm Wako Pure Chemical Corporation) to prepare an NMP solution of polyetherimide. This was coated onto a commercially available polyimide film (thickness 140 μm) using a #20 Meyer bar and dried in an oven at 150°C for 15 minutes to form a polyetherimide resin layer (resin layer A) on the polyimide film. Subsequently, 2.1 g of terpene phenol resin (trade name "TH130", manufactured by Yasuhara Chemical Co., Ltd.), 25 mg of silica particles (x) (average particle diameter 0.7 μm, "Sun Seal" (registered trademark) SS-07, manufactured by Tokuyama Corporation), and 12 g of 2-butanone (manufactured by Fujifilm Wako Pure Chemical Corporation) were mixed to prepare a coating liquid in which the terpene phenol resin was dissolved. This was coated onto the polyetherimide resin layer on the polyimide film using a #4 Meyer bar and dried in an oven at 100°C for 1 minute to form a coating layer (layer B) on the polyetherimide resin layer. The laminate of the polyetherimide resin layer and the coating layer was peeled from the polyimide film to obtain a film for a film capacitor. The evaluation results are shown in Table 1.

[0079] (Example 2) A film for a film capacitor was obtained in the same manner as in Example 1, except that the mixing amounts of the terpene phenol resin, silica particles, and 2-butanone were 0.70 g, 8 mg, and 14.2 g, respectively. The evaluation results are shown in Table 1.

[0080] (Example 3) On the surface of the corona-treated PPS film 1 (resin layer A), coating liquid 1 was uniformly applied using a bar coater so that the film thickness of layer B after curing would be 0.10 μm, and then it was dried in a drying oven at 90°C for 1 minute. Subsequently, it was introduced into a UV irradiation device, and cured under the conditions of illuminance of 50 mW / cm 2 , irradiation dose of 0.1 J / cm 2 , and oxygen concentration of 100 ppm to form layer B. Then, the laminate of resin layer A and layer B was wound up to obtain a film for a film capacitor. The evaluation results are shown in Table 1.

[0081] (Example 4) A film for a film capacitor was obtained in the same manner as in Example 3, except that coating liquid 2 was used instead of coating liquid 1. The evaluation results are shown in Table 1.

[0082] (Example 5) A film for a film capacitor was obtained in the same manner as in Example 3, except that coating liquid 3 was used instead of coating liquid 1 and the drying temperature in the drying oven was set to 120°C. The evaluation results are shown in Table 1.

[0083] (Example 6) 150 g of polyetherimide resin was dissolved in 850 g of N-methyl-2-pyrrolidone to prepare an NMP solution of polyetherimide. This was uniformly applied onto a commercially available polyimide film (thickness 140 μm) using a bar coater so that the thickness of the polyetherimide layer after drying would be 3 μm, and then introduced into a drying oven at 150°C and dried for 5 minutes to form a polyetherimide resin layer (resin layer A) on the polyimide film. Coating liquid 4 was uniformly applied onto the surface of the obtained laminate on the resin layer A side using a bar coater so that the thickness of layer B after curing would be 0.1 μm, and then dried in a drying oven at 90°C for 1 minute. Subsequently, it was introduced into a UV irradiation device, and cured under the conditions of illuminance of 50 mW / cm 2 , irradiation dose of 0.1 J / cm 2 , and oxygen concentration of 100 ppm to form layer B. Subsequently, the laminate of resin layer A and layer B was peeled off from the polyimide film and wound up to obtain a film for a film capacitor. The evaluation results are shown in Table 2.

[0084] (Example 7) A film for a film capacitor was obtained in the same manner as in Example 3, except that Coating Liquid 6 was used instead of Coating Liquid 1. The evaluation results are shown in Table 2.

[0085] (Example 8) A film for a film capacitor was obtained in the same manner as in Example 3, except that Coating Liquid 7 was used instead of Coating Liquid 1, the temperature of the drying oven was changed from 90°C to 150°C, and the drying time was changed from 1 minute to 5 minutes. The evaluation results are shown in Table 2.

[0086] (Example 9) 100 g of cellulose acetate (i) was dissolved in 900 g of methyl ethyl ketone to prepare a methyl ethyl ketone solution of cellulose acetate. This was coated onto a commercially available polyimide film (thickness 140 μm) using a bar coater so that the thickness of the dried cellulose acetate layer became 3.2 μm, and then introduced into a drying oven at 100°C and dried for 2 minutes to form a cellulose acetate resin layer (resin layer A) on the polyimide film. Subsequently, Coating Liquid 7 was coated onto the surface of the obtained laminate on the resin layer A side using a bar coater so that the thickness of the cured layer B became 0.10 μm, and then introduced into a drying oven at 100°C and dried for 1 minute to form layer B on resin layer A. The laminate of resin layer A and layer B was peeled off from the polyimide film and wound up to obtain a film for a film capacitor. The evaluation results are shown in Table 2.

[0087] (Comparative Example 1) A film for a film capacitor consisting only of layer A was obtained in the same manner as in Example 1, except that the step of forming layer B after forming resin layer A was omitted. The evaluation results are shown in Table 3.

[0088] (Comparative Example 2) Coating Liquid 5 was coated onto the surface of PPS Film 1 (resin layer A) that had been subjected to corona treatment with a bar coater so that the thickness of the cured layer B became 0.50 μm, and then dried in an oven at 90°C for 1 minute to form layer B, thereby obtaining a film for a film capacitor. The evaluation results are shown in Table 3.

[0089] (Comparative Example 3) PPS film 1 was evaluated as a film for film capacitors. The evaluation results are shown in Table 3.

[0090] (Comparative Example 4) PPS film 2 was evaluated as a film for film capacitors. The evaluation results are shown in Table 3.

[0091] (Comparative Example 5) As the molding material for the resin layer A, polyetherimide resin [product name: "ULTEM" (registered trademark) 1010-1000-NB (hereinafter abbreviated as "1010-1000"), manufactured by SABIC Innovative Plastics] was prepared. This molding material was placed in a dehumidifying hot air dryer [product name: Multi Jet MJ3, manufactured by Matsui Seisakusho] heated to 150 °C and left for 12 hours to dry. After confirming that the moisture content of this molding material was 300 ppm or less, the molding material was set in a φ40 mm single-screw extruder equipped with a T-die with a width of 900 mm and melt-kneaded. At the same time, the melt-kneaded molding material was continuously extruded from the T-die of the single-screw extruder to extrude and form a film made of polyetherimide resin into a strip shape, and a polyetherimide resin layer with a length of 1000 m and a width of 65 cm was produced. The cylinder temperature of the single-screw extruder was adjusted to 360 - 380 °C, the temperature of the T-die was 385 °C, and the temperature of the connecting pipe connecting the single-screw extruder and the T-die was adjusted to 380 °C respectively. Also, when charging the molding material into the single-screw extruder, nitrogen gas, an inert gas, was supplied at 18 L / min. The formed polyetherimide resin layer was successively wound around a pair of pressure rolls equipped with silicone rubber with an arithmetic mean roughness (Ra) of 0.44 - 0.47 μm, a metal roll which is a cooling roll at 205 °C with a convex handle pattern with an arithmetic mean roughness (Ra) of 1.28 μm on the peripheral surface, and a 6-inch winding tube located downstream thereof, and was sandwiched between each pressure roll and the metal roll and cooled. By sandwiching the polyetherimide resin layer between the pressure roll and the metal roll, a plurality of fine uneven portions were formed on the front and back surfaces of the polyetherimide resin layer respectively. The obtained polyetherimide resin layer with fine uneven portions on the surface was used as the resin layer A. Diparaxylylene was vaporized under the conditions of 180 °C and 10 Pa, thermally decomposed under the conditions of 680 °C and 10 Pa, and the diradical paraxylylene monomer obtained by thermal decomposition was polymerized on the metal roll surface side of the resin layer A under the conditions of 35 °C and 10 Pa, thereby forming a layer B made of polyparaxylylene resin. The obtained laminate was wound up to obtain a film for a film capacitor. The evaluation results are shown in Table 3.

[0092] (Comparative Example 6) A linear polypropylene resin polymerized with a Ziegler-Natta catalyst, having a mesopentad fraction of 0.98, a melting point of 167 °C, and a melt flow rate (MFR) of 2.6 g / 10 min, was supplied to a single-screw melt extruder, melt-extruded at 240 °C, and after removing foreign matter with a sintered filter with a 80-μm cut, the molten polymer was discharged from a T-die. The molten sheet was adhered and cooled and solidified by applying an electrostatic charge on a casting drum maintained at 95 °C to obtain an unstretched sheet. Next, the sheet was gradually preheated to 145 °C with a plurality of roll groups, and then passed through rolls maintained at a temperature of 145 °C with a peripheral speed difference, and stretched 5.0 times in the longitudinal direction. Subsequently, the film was led to a tenter and stretched 8 times in the width direction at a temperature of 165 °C. Then, as the first-stage heat treatment and relaxation treatment, heat treatment was performed at 130 °C while giving a 8% relaxation in the width direction, and as the second-stage heat treatment, heat treatment was performed at 140 °C while gripping the film in the width direction with clips. Thereafter, it was led outside the tenter through a cooling process at 100 °C, the clips at the film ends were released, and a film with a film thickness of 3.0 μm was wound up to obtain a film for a film capacitor. The evaluation results are shown in Table 3.

[0093] (Comparative Example 7) PPS film 3 was used as resin layer A, and a silicone composition (manufactured by Shin-Etsu Chemical Co., Ltd., silicone X-40-2655A) was vapor-deposited on one side thereof by a vacuum vapor deposition method to a thickness of 0.1 μm. Subsequently, a glow discharge treatment was performed on the coated layer surface by generating a glow discharge using a 250-kHz, 5-kW pulsed DC power supply while supplying a small amount of O2 gas (treatment power density E = 27.8 W·min / m2) to form layer B. The obtained laminate was wound up to obtain a film for a film capacitor.

[0094]

Table 1

[0095]

Table 2

[0096]

Table 3

[0097] Note that for Example 1, Example 2, and Comparative Example 1, films were produced in sheets, but since films of a length sufficient for capacitor element processing could not be obtained, capacitor element processing and evaluation of film capacitor characteristics were not performed.

Industrial Applicability

[0098] The film for a film capacitor of the present invention can be applied to various uses such as packaging uses, tape uses, cable wrapping, and electrical uses including capacitors, and can be particularly used for capacitor uses for high voltage that require withstand voltage and reliability at high temperatures.

Claims

1. A resin layer A having a melting point of 180 ° C or higher and / or a glass transition temperature of 130 ° C or higher, and at least one of the outermost film layers has a layer B that is thinner than the resin layer A. When measuring the coefficient of dynamic friction between the same surfaces among the two outermost surface, the surface with the larger coefficient of dynamic friction is defined as the a-surface, and the surface with the smaller coefficient of dynamic friction is defined as the b-surface. When the coefficient of dynamic friction between the a-surfaces is μdaa and the coefficient of dynamic friction between the a-surface and the b-surface is μdab, μdaa> μdab and μdab ≤ 1.2 are satisfied, and at least one of the outermost surface satisfies a load area ratio Smr1 ≥ 12% for separating the protruding peak portion and the core portion, the oxygen atom content of the layer B is 1.0% by mass or more, the dielectric loss tangent is 2.0% or less, the layer B satisfies the following condition (i), and the layer B contains two or more components that are mutually incompatible, a film for a film capacitor. Condition (i): The value XB calculated based on the following formula (a) from the atomic fractions of hydrogen atom H, carbon atom C, sulfur atom S, silicon atom Si, nitrogen atom N, and oxygen atom O contained in the layer B is 0.90 or less. Formula (a) XB = (atomic fraction of carbon atom C in layer B + atomic fraction of nitrogen atom N in layer B + atomic fraction of sulfur atom S in layer B + atomic fraction of silicon atom Si in layer B) / (atomic fraction of hydrogen atom H in layer B + atomic fraction of oxygen atom O in layer B)

2. The film for a film capacitor according to claim 1, wherein the content of silicon atom Si in the layer B is 27% by mass or less.

3. The film for a film capacitor according to claim 1 or 2, wherein the ratio of the protruding peak height Spk-a of the a-surface to the protruding peak height Spk-b of the b-surface satisfies Spk-b / Spk-a ≥ 2.0, and the load area ratio Smr1-b for separating the protruding peak portion and the core portion of the b-surface satisfies Smr1-b ≥ 12%.

4. When the film thickness is T (F), the maximum valley depth Sv of both outermost surfaces satisfies Sv / T (F) <0.

30. The film for a film capacitor according to any one of claims 1 to 3.

5. The film for a film capacitor according to any one of claims 1 to 4, wherein the resin layer A contains at least one resin of polyphenylene sulfide resin, polyetherimide resin, polyphenyl sulfone resin, and polyether sulfone resin in an amount of 50% by mass or more and 100% by mass or less.

6. The film for a film capacitor according to any one of claims 1 to 5, wherein the layer B contains at least one resin selected from an acrylic resin, an epoxy resin, a cellulose derivative, and a polyester resin in an amount of 50% by mass or more and 100% by mass or less.

7. A metal layer laminated film for a film capacitor, having a metal layer on the surface of at least one outermost layer of the film for a film capacitor according to any one of claims 1 to 6.

8. The metal layer laminated film for a film capacitor according to claim 7, having the resin layer A, the layer B, and the metal layer in this order.

9. The layer B is provided only on one surface of the resin layer A, the metal layer is provided on the layer B side, and when the surface with the larger coefficient of kinetic friction measured between the same surfaces among the two outermost layer surfaces is defined as the a surface and the surface with the smaller coefficient of kinetic friction is defined as the b surface, the b surface is on the layer B side when viewed from the resin layer A. The metal layer laminated film for a film capacitor according to claim 8.

10. A film capacitor comprising the metal layer laminated film for a film capacitor according to any one of claims 7 to 9.

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