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

Abstract

An object of the present invention is to provide a film for a thin film capacitor having high heat resistance, self-healing properties, and excellent productivity. The following is the gist of the film for a thin film capacitor. The film for a thin 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. The layer B, which is thinner than the resin layer A, is provided on at least one outermost surface of the film. The oxygen atom content of the layer B is 1.0% by mass or more. When measuring the coefficient of dynamic friction between the same surfaces among the two outermost surfaces, if the surface with the larger coefficient of dynamic friction is designated as surface a and the surface with the smaller coefficient of dynamic friction is designated as surface b, and the coefficient of dynamic friction between surface a and surface a is designated as μdaa and the coefficient of dynamic friction between surface a and surface b is designated as μdab, then μdaa > μdab and μdab ≤ 1.2 are satisfied.

Description

Technical Field

[0001] The present invention relates to a film for a thin film capacitor that serves as a dielectric of a thin film capacitor, a metal laminated film for a thin film capacitor, and a thin film capacitor. Background Art

[0002] In recent years, due to global environmental problems and the like, the market for motor-driven hybrid vehicles (HEVs), plug-in hybrid vehicles (PHEVs), or motor-driven electric vehicles (EVs), fuel cell vehicles (FCVs) has expanded. However, as the market for these motor-driven vehicles expands, the demand for thin film capacitors used in these vehicles has also increased rapidly.

[0003] A thin film capacitor is a capacitor that uses a resin-based substrate film as a dielectric and can obtain excellent frequency characteristics and temperature stability. Examples of the substrate film for the thin film capacitor include polyester resin films such as polypropylene (PP) resin films, polyethylene terephthalate (PET) resin films, polyethylene naphthalate (PEN) resin films, thermoplastic resin films such as polyphenylene sulfide (PPS) resin films, or polyetherimide (PEI) resin films as amorphous thermoplastic resins.

[0004] Among these films, polyetherimide resin films have attracted attention as substrate films (Patent Document 1). This is because, when thin film capacitors are used in applications such as motor-driven hybrid vehicles and motor-driven vehicles, heat resistance to withstand use in an environment of 120°C is required. If a substrate 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, withstand voltage characteristics, and dielectric characteristics can be obtained.

[0005] On the other hand, substrate films such as polyetherimide and polyphenylene sulfide generally have poor self-healing (SH) properties and have the disadvantage that the capacitor capacitance decreases if used for a long time. In response to this, techniques for improving self-healing properties by providing a coating on the substrate film are known (Patent Documents 2 and 3).

[0006] Prior Art Documents

[0007] Patent Documents

[0008] Patent Document 1: Japanese Unexamined Patent Application Publication No. 2007-300126

[0009] Patent Document 2: Japanese Unexamined Patent Application Publication No. 2018-163950

[0010] Patent Document 3: International Publication No. 2007 / 080757 Summary of the Invention

[0011] Problems to be Solved by the Invention

[0012] However, in the prior art, when heat resistance and self-healing properties are both required, there are problems such as using a high-cost poly-p-xylene resin coating that takes a long time to form, has poor productivity, and has a low improvement effect on self-healing properties, and using a silicone-based self-healing coating of silicone oxide that may cause wire defects in the circuit when dielectric breakdown occurs. Therefore, in view of the background of such prior art, the present invention aims to provide a film for thin film capacitors having high heat resistance, self-healing properties, and excellent productivity.

[0013] Means for Solving the Problems

[0014] The above problems can be solved by the following two solutions.

[0015] The first solution of the film for thin film capacitors of the present invention is a film for thin film capacitors having a resin layer A and a layer B, wherein the melting point of the resin layer A is 180 °C or higher and / or the glass transition temperature is 130 °C or higher, and a layer B having a thickness thinner than that of the resin layer A is provided on at least one outermost layer of the film. The oxygen atom content of the above layer B is 1.0 mass% or more. Among the two outermost layer surfaces, when the dynamic friction coefficient is measured between the same surfaces, the surface with the larger dynamic friction coefficient is designated as the a surface, and the surface with the smaller dynamic friction coefficient is designated as the b surface. When the dynamic friction coefficient between the a surfaces is designated as μdaa and the dynamic friction coefficient between the a surface and the b surface is designated as μdab, μdaa > μdab and μdab ≤ 1.2 are satisfied.

[0016] The second solution of the film for thin film capacitors of the present invention is a film for thin film capacitors having a resin layer A and a layer B, wherein the melting point of the resin layer A is 180 °C or higher and / or the glass transition temperature is 130 °C or higher, and a layer B having a thickness thinner than that of the resin layer A is provided on at least one outermost layer of the film. The oxygen atom content of the above layer B is 1.0 mass% or more.

[0017] Effects of the Invention

[0018] According to the present invention, it is possible to provide a film for thin film capacitors having high heat resistance, self-healing properties, and excellent productivity. Detailed Description of the Invention

[0019] The first aspect of the film for thin film capacitors 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. The layer B, which is thinner than the resin layer A in thickness, is provided on at least one of the outermost surfaces of the film. The oxygen atom content of the layer B is 1.0% by mass or more. Among the two outermost surfaces, when measuring the dynamic friction coefficient between the same surfaces, the surface with the larger dynamic friction coefficient is designated as the a surface, and the surface with the smaller dynamic friction coefficient is designated as the b surface. When the dynamic friction coefficient between the a surfaces is designated as μdaa and the dynamic friction coefficient between the a surface and the b surface is designated as μdab, μdaa > μdab and μdab ≤ 1.2 are satisfied.

[0020] The second aspect of the film for thin film capacitors 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. The layer B, which is thinner than the resin layer A in thickness, is provided on at least one of the outermost surfaces of the film. The oxygen atom content of the layer B is 1.0% by mass or more.

[0021] Furthermore, hereinafter, the first aspect of the film for thin film capacitors of the present invention and the second aspect of the film for thin film capacitors of the present invention may sometimes be collectively referred to as the film for thin film capacitors of the present invention. Hereinafter, the film for thin film capacitors of the present invention will be specifically described.

[0022] The film for thin film capacitors 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. The lower limit of the melting point of the resin layer A is preferably 205 °C, more preferably 215 °C. The upper limit is not particularly set, 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. The upper limit is not particularly set, 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 range, when the film for thin film capacitors is used in a high-temperature environment of 120 °C or higher, insulation failure caused by thermal shrinkage or film breakage is less likely to occur.

[0023] The thickness of the resin layer A of the present invention is not particularly limited, but is preferably 100 μm or less, more preferably 10 μm or less. By making the thickness of the resin layer A of the present invention 100 μm or less, it is easy to reduce the volume when manufacturing 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 further preferably 1.6 μm. By making the thickness of the resin layer A 0.50 μm or more, it is easy to increase the insulation breakdown voltage.

[0024] The raw materials used in the resin layer A of the film for the thin film capacitor of the present invention are not particularly limited, and examples thereof include polyolefin resins such as polystyrene (PS) resin, poly-4-methyl-1-pentene (PMP) resin, cyclic olefin polymer (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, polyethersulfone (PES) resin, and polyphenylsulfone (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, polyetherimide (PEI) resin, and polyamideimide (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; fluororesins such as 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), poly(chlorotrifluoroethylene) (PCTFE) resin (also called chlorotrifluoroethylene resin), poly(1,1-difluoroethylene) (PVDE) resin (also called 1,1-difluoroethylene resin), 1,1-difluoroethylene / tetrafluoroethylene / hexafluoropyrene copolymer resin, etc.; polyacetal resin, liquid crystal polymer (LCP) resin, polycarbonate (PC) resin, polyarylate (PAR) resin, phenolic resin, polyurea resin, melamine resin, epoxy resin, alkyd resin, etc.Among them, polyetherimide resin, polycarbonate resin, polyphenylene sulfide resin, polyethersulfone resin, and polysulfone resins such as polyphenylsulfone resin, polyimide resin, polymethylpentene resin, polyetheretherketone resin, polyetherketoneketone resin, and polyaryletherketone resin, which have excellent 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 capacitors, are more preferably used. It is more preferably 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 be used in the form of modified bodies, derivatives, and copolymers with other compounds. In addition, they can be used alone or in combination of two or more.

[0025] In the resin layer A of the film for thin film capacitors of the present invention, antioxidants, light stabilizers, ultraviolet absorbers, plasticizers, lubricants, crosslinking agents, flame retardants, antistatic agents, heat resistance improvers, colorants, slip agents, anti-blocking agents, inorganic particles, resin particles, inorganic compounds, organic compounds, etc. can be contained within the range that does not impair its properties. In addition, these respective components can also be used alone or in combination of multiple types as needed.

[0026] The film for thin film capacitors of the present invention has a layer B with a thickness thinner 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 1.0% by mass or more. The oxygen atom content of the layer B is preferably 1.5% by mass or more, more preferably 21% by mass or more, and further 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 further preferably 34% by mass. By making the oxygen atom content contained in the layer B 1.0% by mass or more, the layer B is liable to volatilize at the time of dielectric breakdown, and the self-healing property can be improved. By making the oxygen atom content contained in the layer B 50% by mass or less, a film with low adhesion between films and excellent productivity can be obtained. In addition, the so-called oxygen atom content of the layer B being 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 set to 100% by mass, the oxygen atoms in the layer B are 1.0% by mass or more. The content of silicon atom Si in the layer B described later can also be interpreted in the same way.

[0027] The thickness of the layer B of the present invention is not particularly limited, but is preferably 10 nm or more, more preferably 50 nm or more. By making the thickness of the layer B 10 nm or more, it becomes easy to improve the self-healing property. In addition, 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, further preferably 0.50 μm, and particularly preferably 0.30 μm. By making the thickness of the layer B 5.0 μm or less, it becomes easy to increase the dielectric breakdown voltage.

[0028] Here, the thickness of each layer can be measured by using the length measurement function through observation of the width-direction - thickness-direction cross-section with a field emission scanning electron microscope, and the detailed procedure will be described later. In addition, the content of atoms in each layer can be obtained from the atomic fraction obtained by analysis using the Rutherford backscattering / hydrogen forward scattering analysis simultaneous measurement method (Pelletron 3SDH manufactured by National Electrostatics Corporation), and the detailed procedure will be described later (not only the oxygen atom content of layer B, but also the other atomic contents of each layer are the same).

[0029] The content of silicon atoms Si in layer B is preferably 27% by mass or less. The upper limit of the content of silicon atoms Si in layer B is more preferably 15% by mass or less, still more preferably 3.0% by mass or less, and further preferably 1.0% by mass or less, and particularly preferably does not contain silicon atoms Si. By making the content of silicon atoms Si contained in layer B 27% by mass or less, deterioration of capacitor characteristics caused by siloxane generated during dielectric breakdown can be suppressed.

[0030] Layer B preferably satisfies the following condition (i).

[0031] Condition (i): The value XB calculated based on the following formula (Ⅱ) from the atomic fractions of hydrogen atoms H, carbon atoms C, sulfur atoms S, silicon atoms Si, nitrogen atoms N, and oxygen atoms O contained in layer B is 0.90 or less.

[0032] Formula (Ⅱ) XB = (atomic fraction of carbon atoms C in layer B + atomic fraction of nitrogen atoms N in layer B + atomic fraction of sulfur atoms S in layer B + atomic fraction of silicon atoms Si in layer B) / (atomic fraction of hydrogen atoms H in layer B + atomic fraction of oxygen atoms O in layer B)

[0033] The upper limit of XB for the above condition (i) is more preferably 0.80, still more preferably 0.70, and particularly preferably 0.65. XB uses the ratio of atoms having a tendency not to evaporate easily and atoms having a tendency to evaporate easily during dielectric breakdown. By making it 0.90 or less, it becomes easier to improve self-healing properties and the reliability of the capacitor. The lower limit of XB is not particularly limited, but is preferably 0.050, and more preferably 0.20. By making XB 0.050 or more, it becomes easier to improve the adhesion between layer B and resin layer A.

[0034] The raw materials used for Layer B are not particularly limited, and resins, low-molecular organic compounds, etc. can be used. From the viewpoint of adhesion to Resin Layer A, resins are preferably used. The resins used for Layer B are not particularly limited, and examples thereof include polyolefin resins such as polystyrene (PS) resin, poly-4-methyl-1-pentene (PMP) resin, cyclic olefin polymer (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 polyethersulfone (PES) resin and polyphenylsulfone (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, polyetherimide (PEI) resin, and polyamideimide (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; fluororesins such as polytetrafluoroethylene (PTFE) resin (also known as tetrafluoroethylene resin), polytetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA) resin (also known as tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer resin), tetrafluoroethylene-hexafluoropropylene copolymer (FEP) resin (also known as tetrafluoroethylene-hexafluoropropylene copolymer resin), tetrafluoroethylene-ethylene copolymer (ETFE) resin (also known as tetrafluoroethylene-ethylene copolymer resin), poly(chlorotrifluoroethylene) (PCTFE) resin (also known as chlorotrifluoroethylene resin), poly(1,1-difluoroethylene) (PVDE) resin (also known as 1,1-difluoroethylene resin), and 1,1-difluoroethylene / tetrafluoroethylene / hexafluoropyrene copolymer resin; polyacetal resins, liquid crystal polymer (LCP) resins, polycarbonate (PC) resins, polyarylate (PAR) resins, phenolic resins, polyurea resins, melamine resins, epoxy resins, alkyd resins, acrylic resins, polymethyl methacrylate resin (PMMA), polyurethane resin (PU), polyurethane acrylate resin, cellulose, cellulose derivatives (e.g., cellulose acetate, carboxymethyl cellulose, hydroxyethyl cellulose, hydroxypropyl methyl cellulose, etc.), petroleum resins, terpene resins, terpene phenol resins, etc.Among these resins, as the resin with a low value of XB and a 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, phenolic resin, cellulose, cellulose derivatives (e.g., cellulose acetate, carboxymethyl cellulose, hydroxyethyl cellulose, hydroxypropyl methyl cellulose, etc.), petroleum resin, terpene resin, and terpene phenol resin are preferably used.

[0035] Among these raw materials, the acrylic resin can improve heat resistance through cross-linking during formation, and the epoxy resin and cellulose derivatives have high heat resistance due to the structure of the main skeleton. By using them as the raw material for layer B, it is easy to extend the life at high temperatures when manufacturing a capacitor element using the capacitor film of the present invention. In addition, the acrylic resin, epoxy resin, cellulose derivatives, and polyester resin are resins containing oxygen atoms, so it is easy to increase the oxygen atom content of layer B and improve self-healing property. Considering these aspects, layer B more preferably contains at least one of the 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 use modified bodies, derivatives, copolymers with other compounds, and resins formed by polymerizing after coating in the form of monomers. In addition, they can be used alone or in combination of two or more.

[0036] From the viewpoint of increasing the height of the protruding peak portion on the surface of layer B and achieving good slidability, the film for a thin film capacitor of the present invention preferably has layer B containing two or more incompatible components. The so-called "incompatible components" here refer to two components that are not uniformly mixed at the molecular level. Specifically, it refers to two components when phases with two different components as the main components both form a phase structure of 0.01 μm or more (whether it conforms to the so-called "main component" can be judged by whether the total content of the two components exceeds 50% by mass in all the components constituting layer B). In addition, for example, when three or more components are included in layer B, if a phase with a certain component as the main component forms a phase structure of 0.01 μm or more, it satisfies "containing two or more incompatible components". Further, when the components constituting layer B are three or more components, if two of them satisfy the above requirements, it is regarded as "containing two or more incompatible components" regardless of whether the remaining other components satisfy the above requirements.

[0037] Whether two or more components are incompatible can be judged by, for example, electron microscopy, differential scanning calorimetry (DSC), and various other methods as described in Polymer Alloys and Blends, Leszek AUtracki, hanser Publishers, Munich Viema New York, P64. The method of mixing two or more incompatible components to increase the height of the protruding peak portion is not particularly limited. Examples include 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 for the material of resin layer A and a resin with low affinity for the material of resin layer A in such a way that the resin with low affinity becomes less, and making the resin with low affinity exist as dots on the surface of layer B as protrusions; a method of dissolving resins with high affinity for each of two solvents with different boiling points and setting the temperature in such a way that one solvent evaporates first during drying, so that the resin dissolved in the remaining solvent precipitates as protrusions later; and a method combining them, etc.

[0038] As a combination of two incompatible components used for layer B, it is preferably a combination of an acrylic resin and a cellulose derivative, a combination of a cellulose derivative and an epoxy resin, or a combination of a methacrylic resin and an acrylic resin. Modified products, derivatives, copolymers with other compounds, and resins formed by polymerizing after coating in monomer form can also be used. When the composition for forming layer B is coated on resin layer A to form it, regarding the combination of these raw materials, it is preferably formed by polymerizing the monomer after coating a coating solution in which one is in polymer form and the other is in monomer form. In addition, if processability is emphasized, for example, a combination of an epoxy resin and silica is also preferred.

[0039] From the viewpoint of long life when used in a capacitor, the film for a thin-film capacitor of the present invention preferably has a dielectric loss tangent of 2.0% or less. From the above viewpoint, the upper limit of the dielectric loss tangent of the film for a thin-film capacitor is preferably 0.70%, more preferably 0.40%, and further preferably 0.30%. When the dielectric loss tangent of the film for a thin-film capacitor is 2.0% or less, the heat generation during energization is reduced when used in a thin-film capacitor, and the life of the thin-film capacitor becomes longer. The lower limit of the dielectric loss tangent of the film for a thin-film capacitor is not particularly limited, but is preferably 0.0010% and more preferably 0.010%. When a resin with a low polarity is used as the resin of resin layer A and a raw material with a dielectric loss tangent higher than that of resin layer A is used as the raw material of layer B, the dielectric loss tangent of the film for a thin-film capacitor can be made small by making the thickness of layer B thin. In addition, the dielectric loss tangent referred to here means the value measured in accordance with JIS C2138-2007, and the detailed measurement method will be described later.

[0040] In the first aspect of the film for thin film capacitors of the present invention, among the two outermost surfaces, when measuring the coefficient of kinetic friction between the same surfaces, the surface with the larger coefficient of kinetic friction is designated as the a surface, and the surface with the smaller coefficient of kinetic friction is designated 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. In addition, the coefficient of kinetic friction between the b surfaces is μdbb. μdab more preferably satisfies μdab ≤ 0.90, further preferably satisfies μdab ≤ 0.75, and particularly preferably satisfies μdab ≤ 0.60. By μdaa > μdab and μdab ≤ 1.2, it is possible to less easily reduce the capacitor characteristics and improve the slidability. Further, by making μdab a low value, the processability can be made higher. The lower limit of μdab is not particularly limited, but preferably 0.10. By making μdab 0.10 or more, when the film for thin film capacitors of the present invention is formed into a wound body, it is less likely to have winding misalignment and becomes easier. In addition, the coefficient of kinetic friction is measured in accordance with JIS K 7125 (1999) under a load of 200 g, at 25 °C, and 65% RH. The detailed procedure will be described later.

[0041] As a method for making μdaa and μdab satisfy μdaa > μdab and μdab ≤ 1.2, there is no particular limitation, and examples include a method of forming a resin layer A on a smooth base film or a mirror roller and forming a layer B thereon in such a way that the raw material contains two incompatible components. When μdab is high, by adjusting the mixing ratio so that the difference in the content of the above two components becomes smaller, μdab can be made low. In addition, in order to make μdaa ≤ μdab, by making μdab low by the above method, or by improving the smoothness of the base film or roller used for forming the resin layer A to make μdaa high, μdaa > μdab can be made.

[0042] The value of μdbb is not particularly limited, but preferably 0.10 or more, and more preferably 0.25 or more. By making μdbb 0.10 or more, it becomes easier to suppress winding misalignment when the film for thin film capacitors of the present invention is formed into a wound body. The upper limit of μdbb is not particularly limited, but preferably 2.0, more preferably 1.5, and further preferably 1.2. By making μdbb 2.0 or less, it becomes easier to improve the processability.

[0043] The value of μdaa is not particularly limited, but it is preferably 0.10 or more, more preferably 0.25 or more. By making μdaa 0.10 or more, it becomes easy to suppress winding misalignment when the film for a thin film capacitor of the present invention is formed into a wound body. The upper limit of μdaa is not particularly limited, but it is preferably 2.0, more preferably 1.5, and further preferably 1.2. By making the value of μdaa 2.0 or less, it becomes easy to improve workability.

[0044] The film for a thin film capacitor of the present invention preferably satisfies a load area ratio Smr1 ≥ 12% that separates the protruding peak portion from the central portion on at least one outermost surface. Since Smr1 focuses on the proportion of the protruding portion, the higher this value, the more effectively the contact area when contacting other surfaces can be reduced. By making Smr1 12% or more, it becomes easy to improve the slidability of the film while increasing the insulation breakdown voltage of the film. The upper limit of Smr1 is not particularly limited, but it is preferably 49%, more preferably 18%. By making Smr1 49% or less, it becomes easy to suppress deformation of the film surface when the film for a thin film capacitor of the present invention is formed into a wound body. In addition, Smr1 can be measured and calculated in accordance with ISO 25178-2:2012 and ISO 25178-3:2012, and the detailed measurement steps will be described later.

[0045] The method for making Smr1 on at least one outermost surface satisfy Smr1 ≥ 12% is not particularly limited, and examples thereof include a method of forming layer B such that the raw material contains two incompatible components. In the case where Smr1 is low, by adjusting the mixing ratio so that the content difference between the two components becomes larger and making the solubility parameters (so-called SP values) of the two components smaller, Smr1 can be increased.

[0046] The atomic fraction XA of hydrogen atoms H, carbon atoms C, sulfur atoms S, silicon atoms Si, nitrogen atoms N, and oxygen atoms O contained in resin layer A preferably satisfies XA > XB with respect to XB based on the following formula (Ⅲ).

[0047] Formula (Ⅲ) XA = (atomic fraction of carbon atoms C in resin layer A + atomic fraction of nitrogen atoms N in resin layer A + atomic fraction of sulfur atoms S in resin layer A + atomic fraction of silicon atoms Si in resin layer A) / (atomic fraction of hydrogen atoms H in resin layer A + atomic fraction of oxygen atoms O in resin layer A)

[0048] The higher XA is, the more likely it is to be a resin with a high degree of unsaturation and a rigid structure. Therefore, by satisfying XA > XB, it becomes easy to improve self-healing properties while maintaining high heat resistance.

[0049] Preferably, the ratio of the peak height Spk-a on the a surface to the peak height Spk-b on the b surface satisfies Spk-b / Spk-a≥2.0, and the load area ratio Smr1-b that separates the peak portion on the b surface from the center is 12% or more. By setting Smr1-b to 12% or more, the slidability of the film can be improved. The upper limit of Smr1-b is not particularly limited, but is preferably 49%. By setting Smr1-b to 49% or less, it becomes easy to suppress deformation of the film surface when the film for a thin film capacitor of the present invention is formed into a wound body. By satisfying Spk-b / Spk-a≥2.0 and Smr1-b≥12%, it becomes easy to obtain a film with excellent slidability. In addition, Spk-a and Spk-b can be measured and calculated in accordance with ISO 25178-2:2012 and ISO 25178-3:2012, and the detailed measurement steps will be described later.

[0050] As a method for making Spk-a, Spk-b, and Smr1-b on at least one of the outermost surfaces satisfy Spk-b / Spk-a≥2.0 and Smr1-b≥12% or more, there is no particular limitation, and examples thereof include a method of forming layer B such that the raw material contains two incompatible components. When Spk-b / Spk-a is low, by increasing the difference in the contents of the above two components and increasing the solubility parameter (so-called SP value) of the two components, Spk-b / Spk-a can be made high. When Smr1-b is low, by adjusting the mixing ratio so that the difference in the contents of the two components becomes larger, or by making the solubility parameter (so-called SP value) of the two components smaller, Smr1-b can be made high.

[0051] Preferably, when the total thickness of resin layer A and layer B is set to T(F), the maximum valley depth Sv of both outermost surfaces of the film for a thin film capacitor of the present invention satisfies Sv / T(F)<0.30. The upper limit of Sv / T(F) is preferably 0.20 on both surfaces. That is, it is more preferably Sv / T(F)≤0.20. Sv / T(F) indicates the size of the depression of the film relative to the thickness, and the higher it is, the more likely it is to cause dielectric breakdown when compared at the same thickness. By making Sv / T(F) less than 0.30, it becomes easy to obtain a film with high withstand voltage characteristics. In addition, Sv can be measured and calculated in accordance with ISO 25178-2:2012 and ISO 25178-3:2012, and the detailed measurement steps will be described later.

[0052] The method for making Sv / T(F) less than 0.30 is not particularly limited. For example, a method can be cited where a resin layer A is formed on a smooth base film or a mirror roller, and after coating the raw material of a solution or liquid layer B thereon with a coater, it is dried to form layer B. When Sv / T(F) on the surface side of layer B becomes 0.30 or more, by adding a leveling agent to the raw material of layer B, Sv / T(F) can be made low.

[0053] Regarding the value of the maximum valley depth Sv of the outermost surfaces on both sides of the film for thin film capacitors of the present invention, it is preferably 0.10 nm or more, more preferably 10 nm or more, for any one surface. By making the maximum valley depth Sv of the outermost surfaces on both sides of the film for thin film capacitors of the present invention 0.10 nm or more for any one surface, it becomes easier to improve processability. The upper limit of the maximum valley depth Sv of the outermost surfaces on both sides of the film for thin film capacitors of the present invention is preferably 5000 nm for any one surface. By making the maximum valley depth Sv of the outermost surfaces on both sides of the film for thin film capacitors of the present invention 5000 nm or less for any one surface, it becomes easier to obtain a film having high withstand voltage characteristics.

[0054] Hereinafter, the metal laminated film for thin film capacitors of the present invention will be described. From the viewpoint of integration, the film for thin film capacitors of the present invention is preferably a metal laminated film for thin film capacitors having a metal layer on at least one outermost surface, and from the purpose of improving self-healing properties, it is more preferably a metal laminated film for thin film capacitors having a resin layer A, a layer B, and a metal layer in this order. In addition, the so-called "having a resin layer A, a layer B, and a metal layer in this order" here means the overall arrangement in which the resin layer A, the layer B, and the metal layer are arranged in this order, regardless of whether there are other layers between the resin layer A and the layer B and between the layer B and the metal layer.

[0055] Furthermore, in order to improve the smoothness of the resin layer A formed of a resin having high heat resistance and thereby exhibit the improvement effect of the slipperiness brought by layer B while maintaining high withstand voltage characteristics, the metal laminated film for thin film capacitors of the present invention particularly preferably has the above-mentioned layer B only on one surface of the resin layer A, has the above-mentioned metal layer on the layer B side, and when, among the two outermost surfaces, the surface with a larger coefficient of kinetic friction measured between the same surfaces is defined as surface a and the surface with a smaller coefficient of kinetic friction is defined as surface b, surface b is on the layer B side when viewed from the resin layer A.

[0056] The thickness of the metal layer is preferably 1 nm or more and 100 nm or less, more preferably 5 nm or more and 80 nm or less, and still more preferably 10 nm or more and 50 nm or less. In addition, the surface resistance value of the metal layer is preferably 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 still 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 known as self-repair property) decreases, which is not preferable. On the contrary, when it exceeds 10 Ω / sq, the reason is that the dielectric loss tangent may deteriorate.

[0057] The film for a thin 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 viewpoint of electrode configuration, it can be either a foil-wound capacitor or a metal-evaporated thin film capacitor, and is also preferably used for an oil-impregnated capacitor impregnated with insulating oil or a dry capacitor that does not use insulating oil at all. In addition, from the viewpoint of shape, it can be a wound type or a stacked type. Among them, from the viewpoint of the characteristics of the film of the present invention, it is preferably used as a metal-evaporated thin 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 with excellent productivity is preferred. When evaporating the metal layer, an oil method, a belt, etc. are used. The evaporation pattern of the metal layer is not particularly limited, and as a preferred pattern, for example, a T blank pattern, a honeycomb pattern, a mosaic pattern, etc. can be cited.

[0058] Next, the thin film capacitor of the present invention will be described. The thin film capacitor of the present invention is formed using the metal layer laminated film for a thin film capacitor of the present invention. The thin film capacitor of the present invention can be a part of an automotive inverter and / or converter (for example, an inverter for a hybrid vehicle, a converter for a hybrid vehicle, an inverter for an electric vehicle, a converter for an electric vehicle, etc.).

[0059] Next, an example of a method for manufacturing the film for a thin film capacitor of the present invention will be described. In addition, the following example has a two-layer structure including a resin layer A and a layer B, but the film for a thin film capacitor of the present invention can have a two-layer structure as long as it has a resin layer A and a layer B, or can have a three-layer or more structure with other layers. In the case of a three-layer or more structure, the layer with the highest thickness and a melting point of 180 °C or more and / or a glass transition temperature of 130 °C or more is set as the resin layer A.

[0060] First, as a method for forming the resin layer A, examples include a method of supplying the raw material of the resin layer A to an extruder, melt-extruding it from a slit die such as a T-die, and curing it on a cooling drum or the like to form the resin layer A; 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 with improved releasability by silicone coating thereon using a coater, and then drying it to form the resin layer A; a method of casting the liquid on a casting belt and then drying it to form the resin layer A, etc. Among them, from the viewpoint of improving the smoothness of the resin layer A, it is preferably carried out by any of the following methods: 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 using a coater and then drying it; or a method of supplying the raw material to an extruder, melt-extruding it from a slit die such as a T-die, curing it on a cooling drum or the like to form a film shape, and then stretching it uniaxially or biaxially, and setting the obtained layer as the resin layer A. When forming the resin layer A on a base film, the resin layer A can be peeled off from the base film before forming the layer B, or it can be not peeled off, but from the viewpoint of improving the transportability, it is preferably carried out without peeling off when forming the layer B.

[0061] As a method for forming the layer B on one side of the resin layer A, examples include a method of coating a solution or liquid raw material of the layer B on the resin layer A using a coater and then drying it, and a method of vacuum-depositing the raw material of the layer B on the resin layer A. From the viewpoint of increasing the protrusion height of the formed layer B, it is preferably formed by a method of coating a solution or liquid raw material of the layer B on the resin layer A using a coater and then drying it. When forming by coating the raw material of the layer B on one side of the resin layer A, the coated surface of the resin layer A can be pre-treated by surface treatment such as corona discharge treatment. By performing surface treatment such as corona discharge treatment, the wettability of the coating composition to the coated surface is improved, the repulsion of the coating composition is 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 preferably to vapor-deposit the metal on the layer B by vacuum evaporation. As the metal used for vapor deposition, aluminum is preferred. At this time, other metal components such as nickel, copper, gold, silver, chromium, and zinc can also be vapor-deposited simultaneously or sequentially with aluminum. When laminating a metal layer on the film composed of the resin layer A and layer B by vapor deposition, the vapor deposition surface of the film can be pre-treated by surface treatment such as corona discharge treatment before vapor deposition. By performing surface treatment such as corona discharge treatment, the adhesion of the vapor-deposited metal to the film can be improved.

[0062] When forming layer B, it is preferable to crosslink the components of layer B. The method of crosslinking is not particularly limited, and examples thereof include a method of using a compound having a plurality of reactive sites as a raw material for layer B and performing a crosslinking reaction by heat or ultraviolet rays. Examples of the compound having a plurality of reactive sites include acrylates having two or more vinyl groups, epoxy compounds having two or more epoxy groups, condensates of melamine and formaldehyde, and the like. Among them, from the viewpoint of increasing the oxygen concentration of layer B and improving self-healing properties, acrylates having two or more vinyl groups are preferably used. In order to promote the crosslinking reaction, additives such as acids, bases, cationic initiators, anionic initiators, and radical initiators can be added according to the reactivity of the reactive sites 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 liquid added with a radical initiator that generates radicals by ultraviolet rays can be prepared, and after coating this coating liquid on the resin layer A, ultraviolet rays are irradiated to promote the crosslinking reaction. The radical initiator is not particularly limited, but a hydroxyalkyl phenyl ketone type initiator or an aminophenyl acetone type initiator that generates radicals by ultraviolet rays can be used. By crosslinking layer B, it becomes easy to improve the heat resistance of the film for thin film capacitors of the present invention.

[0063] Examples

[0064] Hereinafter, the film for thin film capacitors of the present invention will be specifically described using examples. In addition, the measurement method of characteristic values and the evaluation method of effects are as described below.

[0065] (1) Film thickness T(F)

[0066] The thickness of any 10 places of the film was measured using a contact type electronic micrometer (K-312A type) manufactured by Anritsu Corporation at 23 °C and 65% RH. The arithmetic average of the thicknesses of these 10 places was defined as the film thickness T(F).

[0067] (2) Thickness T(A) of resin layer A and thickness T(B) of layer B

[0068] Using the sectioning method, an ultra-thin section with a width of 5 mm having a cross-section along the width direction - thickness direction of the film was prepared, and platinum was coated on this cross-section 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 the resin layer A and the thickness of layer B were measured from an arbitrary position of the observation image. In addition, the thicker layer of the two layers was defined as the resin layer A, the thinner layer was defined as layer B, and the observation magnification was set to 10,000 times. Further, the same measurement was performed 20 times in total, and the average value thereof was used as the thickness T(A) of the resin layer A and the thickness T(B) of layer B.

[0069] (3) Melting point and glass transition temperature of Resin Layer A

[0070] Weigh 5 mg of Resin Layer A determined by the steps described in (2), and using a differential scanning calorimeter (EXSTAR DSC6220 manufactured by Seiko Instruments), heating and cooling were carried out in a nitrogen atmosphere according to the following procedure.

[0071] <Procedure>

[0072] Step 1: Heat from 25°C to 330°C at a rate of 10°C / minute, and then hold at 330°C for 5 minutes.

[0073] Step 2: Cool from 330°C to 25°C at a rate of -10°C / minute, and then hold at 25°C for 5 minutes.

[0074] Step 3: Heat from 25°C to 330°C at a rate of 10°C / minute, and then hold at 330°C for 5 minutes.

[0075] During the heating process of Step 3, when observing the DSC curve from 330°C towards the lower temperature side, the maximum temperature at which the slope of the DSC curve changes based on the slope of the baseline is set as T_1, the minimum temperature at which the slope of the DSC curve returns to the slope of the baseline at a temperature lower than T_1 is set as T_2, and the value Tg obtained by the following calculation formula is set as the glass transition temperature of Resin Layer A.

[0076] <Calculation formula>

[0077] Tg = (T_1 + T_2) / 2.

[0078] In addition, the peak temperature of the endothermic curve obtained through Step 3 is set as the melting point of Resin Layer A. In the case where multiple peak temperatures can be observed, the highest temperature is set as the melting point of Resin Layer A. However, if no peak is observed in the endothermic curve obtained through Step 3, and during the heating process of Step 3, when observing the DSC curve from 330°C towards the lower temperature side, if the slope of the DSC curve does not change based on the slope of the baseline in the region above 25°C, both the melting point and the glass transition temperature of Resin Layer A are set to 330°C or higher. If no peak is observed in the endothermic curve obtained through Step 3, but the glass transition temperature is less than 330°C, it is set as no melting point. During the heating process of Step 3, when observing the DSC curve from 330°C towards the lower temperature side, if the slope of the DSC curve does not change based on the slope of the baseline in the region above 25°C, but the melting point is less than 330°C, it is set as no glass transition temperature. In the corresponding cases, they are recorded as "-" in Tables 1 - 3 respectively.

[0079] (4) Atomic fractions of hydrogen atoms (H), carbon atoms (C), sulfur atoms (S), silicon atoms (Si), nitrogen atoms (N), and oxygen atoms (O) contained in resin layer A and layer B, and contents of oxygen atoms (O) and silicon atoms (Si) in layer B

[0080] The surface on the resin layer A side of the film was analyzed by Rutherford backscattering / hydrogen forward scattering analysis simultaneous determination method (Pelletron 3SDH manufactured by National Electrostatics Corporation), and atomic yields Y(H), Y(C), Y(S), Y(Si), Y(N), and Y(O) of hydrogen atoms (H), carbon atoms (C), sulfur atoms (S), silicon atoms (Si), nitrogen atoms (N), and oxygen atoms (O) in resin layer A were obtained. Values obtained from the obtained values based on the following formula were set as atomic fractions of hydrogen atoms (H), carbon atoms (C), sulfur atoms (S), silicon atoms (Si), nitrogen atoms (N), and oxygen atoms (O) contained in resin layer A.

[0081] <Calculation formula>

[0082] Y(All) = Y(C) + Y(S) + Y(Si) + Y(N) + Y(O) + Y(H).

[0083] Atomic fraction of hydrogen atom H = Y(H) / Y(All)

[0084] Atomic fraction of carbon atom C = Y(C) / Y(All)

[0085] Atomic fraction of sulfur atom S = Y(S) / Y(All)

[0086] Atomic fraction of silicon atom Si = Y(Si) / Y(All)

[0087] Atomic fraction of nitrogen atom N = Y(N) / Y(All)

[0088] Atomic fraction of oxygen atom O = Y(O) / Y(All).

[0089] Regarding layer B, the surface analyzed by Rutherford backscattering / hydrogen forward scattering analysis simultaneous determination method was set as the surface on the layer B side. Except for this, analysis and calculation of each value were performed by the same procedure, and atomic fractions of hydrogen atoms (H), carbon atoms (C), sulfur atoms (S), silicon atoms (Si), nitrogen atoms (N), and oxygen atoms (O) contained in layer B were set. In addition, contents of oxygen atoms (O) and silicon atoms (Si) in layer B were calculated based on the following formula. In addition, atomic fractions Y(C), Y(S), Y(Si), Y(N), Y(O), Y(H) in the formula are all values of layer B.

[0090] <Calculation formula>

[0091] Content (mass %) of oxygen atom O = 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))

[0092] Content (mass %) of silicon atom Si = 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))

[0093] In addition, the measurement conditions are as described below.

[0094] Incident ion: 4 He ++

[0095] Incident energy: 2300 keV

[0096] Incident angle: 75 deg

[0097] Scattering angle: 160 deg

[0098] Recoil angle: 30 deg

[0099] Specimen current: 4 nA

[0100] Beam diameter: 2 mm φ

[0101] In-plane rotation: None

[0102] Exposure: 0.5 μC × 20 points

[0103] (5) XA, XB

[0104] Using the values obtained by the method described in (4), XB is calculated by the following formula (II), and XA is calculated by the following formula (III).

[0105] Formula (II) 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)

[0106] Formula (III) 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).

[0107] (6) Coefficient of kinetic friction (μdaa, μdab, μdbb)

[0108] The dynamic friction coefficient was measured using a sliding tester manufactured by Toyo Seiki Seisaku-sho, Ltd. in accordance with JIS K 7125 (1999) under a load of 200 g, at 25°C, and 65% RH. In addition, when one side of the film was designated as the α side and the other side as the β side, measurements were made for two cases: when the α sides were overlapped with each other and when the β sides were overlapped with each other. The measurements were carried out three times each, and the average value of the obtained values was calculated and set as the dynamic friction coefficient for the case of measurement with each side against each other. When the surface with the larger dynamic friction coefficient during measurement with each side of the α side and the β side overlapped with each other was designated as the a side and the surface with the smaller dynamic friction coefficient was designated as the b side, the dynamic friction coefficient between the a sides was set as μdaa, and the dynamic friction coefficient between the b sides was set as μdbb. Further, three measurements were made for the case of overlapping the a side and the b side, and the average value of the obtained values was calculated and set as μdab. In addition, when the frictional force detected by the load sensor during measurement exceeded 5.9 N for each case, the measurement was interrupted, and the measured value of the dynamic friction coefficient in that case was set to >3.0. When the dynamic friction coefficients in the case of measurement with the same sides against each other were equal or >3.0, the side with the higher arithmetic mean roughness Sa measured by the method described below was designated as the b side.

[0109] (7) Arithmetic mean roughness Sa, load area ratio Smr1, protrusion height Spk, maximum valley depth Sv

[0110] Each parameter was measured and calculated in accordance with ISO 25178-2:2012 and 25178-3:2012. Among them, the measurement was carried out using a scanning white interferometer microscope "VS1540" (manufactured by Hitachi High-Technologies Corporation, and the measurement conditions and device configuration will be described later). After supplementing and processing (fully supplementing) the captured image through the attached analysis software, surface correction was performed using a fourth-degree polynomial approximation, and then processing was carried out using a median filter (3×3 pixels). The processed image was measured. In addition, 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 square shape of 5 cm × 5 cm. The intersection point of the diagonal was set as the first measurement point (starting point), and positions 1 cm away from the starting point towards the four corners were respectively determined as the second to fifth measurement points, with a total of five measurement positions. Measurements were taken at each measurement position, and Sa, Smr1, Spk, and Sv at each measurement position were calculated according to the above steps. The average values of each were used as Sa, Smr1, Spk, and Sv of the film. In addition, specifically, the value of Spk on side a was denoted as Spk-a, and the values of Spk and Smr1 on side b were denoted as Spk-b and Smr1-b respectively. Spk-b / Spk-a was calculated from the obtained values of Spk-a and Spk-b. Sv / T(F) was calculated from the obtained values of Sv on each side and the above-mentioned value of T(F).

[0111] <Measurement conditions and device configuration>

[0112] Objective lens: 10x

[0113] Eyepiece tube: 1x

[0114] Zoom lens: 1x

[0115] Wavelength filter: 530 nm white

[0116] Measurement mode: Wave

[0117] Measurement software: VS-Measure 10.0.4.0

[0118] Analysis software: VS-Viewer10.0.3.0

[0119] Measurement area: 561.1 μm × 561.5 μm

[0120] Number of pixels: 1,024 × 1,024.

[0121] (8) SH defect rate, self-healing property

[0122] On the surface of side B of the layer at 25 W·min / m 2The treatment intensity was subjected to corona discharge treatment in the atmosphere. In addition, in the film without layer B, the b surface was treated at 25 W·min / m 2 The treatment intensity was subjected to corona discharge treatment in the atmosphere. Then, the corona discharge treated surface was vapor-deposited with commercially available aluminum using a bell jar type vacuum evaporation 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 laminated film was obtained. The obtained metal laminated film was cut into a rectangular shape of 12 cm × 7.5 cm with the length direction as the long side as a test piece.

[0123] On a copper plate of 1 m × 2 m, a 10 cm square "Teflon" (registered trademark) sheet with a thickness of 1 mm was set. On the "Teflon" (registered trademark) sheet, the test piece was set in such a way that the short side of the test piece was parallel to one side of the "Teflon" (registered trademark) sheet, and the test piece was placed on the "Teflon" (registered trademark) sheet in a region 1 cm from the short side end on one side of the test piece. The test piece was sandwiched by about 2 cm 2 In the way of, a 5 cm square plate-shaped conductive rubber electrode was placed on the "Teflon" (registered trademark) sheet. Further, a 3 cmφ cylindrical electrode was set on the rubber electrode in such a way that the center of gravity was on the region where the rubber electrode, the test piece, and the "Teflon" (registered trademark) sheet overlapped. The cylindrical electrode and the copper plate were connected to a DC power supply via wires respectively, and a voltage of 100 VDC was applied as the initial voltage. After 15 seconds at this voltage, the applied voltage was gradually increased stepwise at 100 VDC / 30 seconds until the initial voltage + 800 VDC, and this operation was repeated to perform a so-called step-up test to generate multiple insulation breakdown marks on the metal laminated film.

[0124] Visually observe the generated insulation breakdown marks. Set the insulation breakdown marks where two or more insulation breakdown marks overlap as one SH defective position, and set the insulation breakdown marks that are not like that as one normal position, find their respective numbers, and calculate the SH defective rate by the following formula. The same measurement was performed 2 times, and the average value was used as the SH defective rate of the film. In addition, in the case where no insulation breakdown occurred, the initial voltage was set to 900 VDC and the same measurement was performed. In the case where no insulation breakdown occurred even at an initial voltage of 10,000 VDC, the SH defective rate was set to 0%.

[0125] <Calculation formula>

[0126] SH defective rate (%) = 100×(number of SH defective positions) / (number of normal positions + number of SH defective positions)

[0127] Based on the SH defective rate of the film, the self-healing property was evaluated as follows.

[0128] S: The defective rate of SH is 16% or less.

[0129] A: The defective rate of SH is greater than 16% and 22% or less.

[0130] B: The defective rate of SH is greater than 22% and 30% or less.

[0131] C: The defective rate of SH is greater than 30%.

[0132] (9) Evaluation of processability

[0133] Corona discharge treatment was carried out in the atmosphere on the surface on the B-layer side at a treatment intensity of 25 W·min / m 2 In the film without the B-layer, corona discharge treatment was carried out in the atmosphere on the b-surface at a treatment intensity of 25 W·min / m 2 Subsequently, the corona discharge treated surface was subjected to vacuum evaporation of commercially available aluminum using a bell-jar type vacuum evaporation apparatus at a gas pressure of 1.0×10 -3 Pa and a filament voltage of 2.6 kV to form a 50-nm evaporation coating film, thereby obtaining a metal laminated film. The obtained metal laminated film was cut into a rectangular shape of 12 cm × 7.5 cm with the length direction as the long side as a test piece. Using a sliding tester manufactured by Toyo Seiki Co., Ltd., in accordance with JIS K 7125 (1999), the dynamic friction coefficient between the metal evaporation surface and the surface without evaporated metal of the obtained metal laminated film was measured 3 times under a load of 200 g, at 25°C, and 65% RH, and the average value of the obtained values was set as the dynamic friction coefficient μM of the metal laminated film. In addition, when the frictional force detected by the load cell during the measurement exceeded 5.9 N, the measurement was interrupted, and the measured value of μM in this case was set as >3.0. Based on the obtained μM, the processability of the film was determined according to the following criteria.

[0134] S: μM is 0.60 or less.

[0135] A: μM is greater than 0.60 and 0.90 or less.

[0136] B: μM is greater than 0.90 and 1.5 or less.

[0137] C: μM is greater than 1.5.

[0138] (10) Dielectric loss tangent

[0139] The dielectric loss tangent was measured in accordance with JIS C2138-2007. First, the film was cut into a square shape of 6 cm × 6 cm, and the surface on the B-layer side was treated at 25 W·min / m 2The treatment intensity was subjected to corona discharge treatment in the atmosphere. In addition, in the film without Layer B, the b surface was treated at 25 W·min / m 2 The treatment intensity was subjected to corona discharge treatment in the atmosphere. Subsequently, the corona discharge treated surface was vapor-deposited with commercially available aluminum using a bell jar type vacuum evaporation apparatus at a gas 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 that was not subjected to corona discharge treatment, in such a manner that the center of the electrode formed on the corona discharge treated surface was in the same position as the center, commercially available aluminum was vapor-deposited using a bell jar type vacuum evaporation apparatus at a gas 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 5.6 cm and a thickness of 50 nm, and a test piece was obtained. The obtained test piece was measured for the dielectric loss tangent using an E4980A Precision LCR Meter (manufactured by Keysight Technologies) by the contact method at 23°C, a relative humidity of 50%, and a frequency of 10 kHz with n = 5, and the average value of the obtained values was set as the dielectric loss tangent of the film.

[0140] (11) Evaluation of the film insulation breakdown voltage at 150°C

[0141] After heating the film in an oven maintained at 150°C for 1 minute, the measurement was carried out in this atmosphere according to JIS C2330 (2001) 7.4.11.2B method (flat plate electrode method). Among them, for the lower electrode, a substance obtained by placing "Conductive Rubber E-100<65>" manufactured by Tokawa Rubber Co., Ltd. of the same size on a metal plate described in the B method of JIS C2330 (2001) 7.4.11.2 was used. The insulation breakdown voltage test (the above measurement) was carried out 30 times, and among the total 30 measured values (calculated values) obtained by dividing the obtained values by the thickness of the film (measured in the above (1)) and converting them to (V / μm), excluding 5 points in descending order from the maximum value and 5 points in ascending order from the minimum value, the average value of the remaining 20 points was calculated and set as the film insulation breakdown voltage at 150°C. From the obtained film insulation breakdown voltage at 150°C, the film insulation breakdown voltage at 150°C was evaluated as follows.

[0142] S: The film insulation breakdown voltage at 150°C is 270 V / μm or more.

[0143] A: The film insulation breakdown voltage at 150°C is 240 V / μm or more and less than 270 V / μm.

[0144] B: The film insulation breakdown voltage at 150°C is 210 V / μm or more and less than 240 V / μm.

[0145] C: The film insulation breakdown voltage at 150 °C is 100 V / μm or more and less than 210 V / μm.

[0146] D: The film insulation breakdown voltage at 150 °C is less than 100 V / μm or the film shrinkage is large and cannot be evaluated.

[0147] (12) Evaluation of thin film capacitor characteristics (reliability at 150 °C)

[0148] The surface on the layer B side of the film was subjected to corona discharge treatment in the atmosphere at a treatment intensity of 25 W·min / m 2 In addition, in the film without layer B, the b surface was subjected to corona discharge treatment in the atmosphere at a treatment intensity of 25 W·min / m 2 Then, on the corona discharge treated surface, aluminum was deposited using a vacuum evaporation machine manufactured by ULVAC, Inc. with a film resistance of 10 Ω / sq and in accordance with a so-called T-shaped blank evaporation pattern having a blank portion provided in a direction perpendicular to the length direction (the lengthwise pitch (period) is 17 mm and the fuse width is 0.5 mm through the masking oil). After cutting, an evaporated roll with a film width of 50 mm (end blank width 2 mm) was obtained. Then, using this roll, a thin film capacitor element was wound using a component winding machine (KAW-4NHB) manufactured by Kaido Seisakusho Co., Ltd. After metal spraying, heat treatment was performed at a temperature of 130 °C for 8 hours under reduced pressure, and leads were installed to complete a thin film capacitor element. Using 10 capacitor elements obtained by such operations, a voltage of 250 VDC was applied to the capacitor elements at a high temperature of 150 °C. After 10 minutes at this voltage, the applied voltage was gradually increased stepwise at 50 VDC / 1 minute, and this operation was repeated to perform a so-called step-up test. After the voltage was increased until the capacitance decreased to 12% or less relative to the initial value, the capacitor elements were disassembled and the failure state was investigated, and the thin film capacitor characteristics were evaluated as follows.

[0149] S: The thin film capacitor element has no change in shape, and no through-type failure is observed.

[0150] A: The thin film capacitor element has no change in shape, and through-type failure within 5 layers of the film is observed.

[0151] B: The thin film capacitor element has no change in shape, and through-type failure penetrating 6 to 7 layers of the film is observed.

[0152] C: A change in the shape of the thin film capacitor element is confirmed. Or through-type failure penetrating 8 to 14 layers of the film is observed.

[0153] D: The shape of the thin-film capacitor element has changed significantly and been damaged, or the processability of the film is poor, and the thin-film capacitor element cannot be fabricated.

[0154] -: The evaluation of the thin-film capacitor characteristics has not been performed.

[0155] S can be used without problems, A can be used according to conditions, B can be used although its practical performance is poor, C can be used although its practical performance is poor according to conditions. D is substantially difficult to use as a capacitor film.

[0156] [Resin, film, coating liquid]

[0157] Polyphenylene sulfide resin particles 1 (PPS particles 1):

[0158] Into a 1-liter autoclave equipped with an industrial stirrer, 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 were added. While stirring at 250 rpm and while introducing nitrogen at normal pressure, the mixture was slowly heated over about 3 hours until 225°C. After distilling off 212 g of water and 4 g of NMP, 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. Then, while stirring at 240 rpm, the temperature was raised at a rate of 0.6°C / minute until 200°C to 235°C. After reaching 235°C, the reaction was continued at 235°C for 95 minutes. Then, the temperature was raised at a rate of 0.8°C / minute until 270°C 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, the temperature was cooled at a rate of 1.0°C / minute until 200°C, and then cooling water at room temperature was supplied to the autoclave to cool until near room temperature. Next, the content was taken out, diluted with 0.4 liters of NMP, stirred at 85°C for 30 minutes, and then the solvent and solid matter were separated by filtration through a sieve (80 mesh). Further, 0.5 liters of NMP was added to the obtained solid matter and stirred at 85°C for 30 minutes, and the solid matter was separated by filtration. Then, the obtained solid matter was washed 3 times with 0.9 liters of warm water and separated by filtration. To the particles (solid matter) obtained by such operation, 1 liter of warm water was added and washed 2 times, and polymer particles were obtained by filtration separation. After hot air drying at 80°C, it was dried under reduced pressure at 120°C to obtain particles (PPS particles 1) of polyphenylene sulfide (PPS) resin having a melting point of 280°C and a weight-average molecular weight of 70,000.

[0159] PPS raw material 1 for film (PPS1):

[0160] PPS particles 1 were fed into a co-rotating twin-screw kneading extruder (manufactured by Japan Steel Works, screw diameter 30 mm, screw length / screw diameter = 45.5) with a vent port and heated to 320°C. They were melt-extruded in a strip form with a residence time of 90 seconds and a screw rotation speed of 150 revolutions per minute, and cooled with water at 25°C. Then, they were immediately cut to produce sheet materials, and PPS raw material 1 for film (PPS1) was obtained.

[0161] PPS raw material for film (PPS2):

[0162] 100 parts by mass of PPS particles 1, 0.05 parts by mass of calcium carbonate particles 1 with an average particle diameter of 0.7 μm (manufactured by Nitto Powder Industries Co., Ltd., "NITOREX" #30PS), and 0.2 parts by mass of calcium stearate were mixed, and the resulting mixed powder was granulated to prepare resin particles with PPS as the main component. The resulting resin particles were fed into a co-rotating twin-screw kneading extruder (manufactured by Japan Steel Works, screw diameter 30 mm, screw length / screw diameter = 45.5) and heated to 320°C. They were melt-extruded in a strip form with a residence time of 90 seconds and a screw rotation speed of 150 revolutions per minute, and cooled with water at 25°C. Then, they were immediately cut to produce sheet materials, and PPS raw material 2 for film (PPS2) was obtained.

[0163] PPS film 1:

[0164] As raw material, PPS1 was vacuum-dried at 180°C for 3 hours. Then, it was fed into an extruder, melted at 320°C in a nitrogen atmosphere, and introduced into a T-die. Then, it was extruded in a sheet form from the T-die to produce a molten single-layer sheet, which was discharged onto a casting drum with a surface temperature maintained at 25°C and a rotational speed of 4.0 m / min. It was consolidated and cooled and cured by electrostatic application to obtain an unstretched film. The resulting unstretched film was used in a longitudinal stretching machine composed of a plurality of heated roller groups, and stretched at a stretching temperature of 103°C in the length direction of the film at a ratio of 3.1 times using the circumferential speed difference of the rollers. Then, both ends in the width direction of the resulting uniaxially stretched film were supported by jigs and led to a tenter, and stretched at a ratio of 3.3 times in the width direction at a stretching temperature of 100°C. Then, it was heat-treated at 280°C, followed by a 2% relaxation treatment, and cooled to room temperature. Then, the film surface (the side in contact with the casting drum) was subjected to corona discharge treatment in the atmosphere at a treatment intensity of 25 W·min / m 2 and the film edges were removed to obtain a biaxially stretched PPS film with a thickness of 4.5 μm.

[0165] PPS film 2:

[0166] As a raw material, PPS2 was used instead of PPS1, and the same operations as those for PPS film 1 were carried out to obtain a biaxially stretched PPS film with a thickness of 4.6 μm.

[0167] Coating solution 1:

[0168] A coating solution obtained 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).

[0169] Coating solution 2:

[0170] A coating solution obtained 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).

[0171] Coating solution 3:

[0172] A coating solution obtained by mixing 80 g of acrylate (I), 11 g of epoxy resin (trade name “EPICLON” 850, active group equivalent 189 eq / g, manufactured by DIC Corporation), 9.0 g of 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.).

[0173] Coating solution 4:

[0174] A coating solution obtained by mixing 99.5 g of acrylate (II), 500 mg of an acrylic resin (trade name "MP-1451", non-crosslinked acrylic particles, manufactured by Soken Chemical & Engineering Co., Ltd., average particle size 150 nm), 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).

[0175] Coating solution 5:

[0176] A coating solution obtained 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), 500 mg of an acrylic resin (trade name "MP-1451", non-crosslinked acrylic particles, manufactured by Soken Chemical & Engineering Co., Ltd., average particle size 150 nm), 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.).

[0177] Coating solution 6:

[0178] A coating solution obtained 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).

[0179] Coating solution 7:

[0180] A coating solution obtained by mixing 500 mg of an acrylic resin (trade name "MP-1451", non-crosslinked acrylic particles, manufactured by Soken Chemical & Engineering Co., Ltd., average particle size 150 nm), 99.5 g of cellulose acetate (i), and 900 g of 2-butanone (manufactured by FUJIFILM Wako Pure Chemical Corporation).

[0181] Coating solution 8:

[0182] A coating solution obtained by mixing 99.9 g of nitrile 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" (registered trademark) P015S0, particle size 150 nm), and 900 g of 2-butanone (manufactured by FUJIFILM Wako Pure Chemical Corporation).

[0183] Coating solution 9:

[0184] A coating solution obtained by mixing 54 g of epoxy resin (trade name “EPICLON” (registered trademark) 850, active group equivalent 189 eq / g, manufactured by DIC Corporation), 45.5 g of 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, “シーホスター” (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.).

[0185] Coating solution 10:

[0186] A coating solution obtained by mixing 100 g of acrylate (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).

[0187] Coating solution 11:

[0188] A coating solution obtained by mixing 99.5 g of polyetherimide (trade name “ULTEM” (registered trademark) Resin 1010, manufactured by SABIC, glass transition temperature 217°C), 500 mg of calcium carbonate particles 2, and 900 g of N-methylpyrrolidone (manufactured by Fujifilm Wako Pure Chemical Corporation).

[0189] (Example 1)

[0190] Dissolve 15 g of polyetherimide resin (trade name “ULTEM” (registered trademark) Resin 1010, manufactured by SABIC, glass transition temperature 217 °C) in 85 g of N-methyl-2-pyrrolidone (manufactured by Fujifilm Wako Pure Chemical Corporation) to prepare an NMP solution of polyetherimide. Coat it on a commercially available polyimide film (thickness 140 μm) using a #20 doctor blade, and dry it in an oven at 150 °C for 15 minutes to form a polyetherimide resin layer (resin layer A) on the polyimide film. Next, mix 2.1 g of terpene phenol resin (trade name “TH130”, manufactured by Yasuhara Chemical), 25 mg of silica particles (x) (average particle size 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), and dissolve the terpene phenol resin to prepare a coating solution. Coat it on the polyetherimide resin layer on the polyimide film using a #4 doctor blade, and dry it in an oven at 100 °C for 1 minute to form a coating (layer B) on the polyetherimide resin layer. Peel the laminate of the polyetherimide resin layer and the coating from the polyimide film to obtain a film for thin film capacitor. The evaluation results are shown in Table 1.

[0191] (Example 2)

[0192] Use 0.70 g, 8 mg, and 14.2 g of the terpene phenol resin, silica particles (x), and 2-butanone, respectively, and perform the same operations as in Example 1 to obtain a film for thin film capacitor. The evaluation results are shown in Table 1.

[0193] (Example 3)

[0194] On the corona-treated surface of the PPS film 1 (resin layer A), uniformly coat the coating solution 1 using a rod coater so that the film thickness of the cured layer B becomes 0.10 μm, and then dry it in a drying oven at 90 °C for 1 minute. Next, introduce it into a UV irradiation device, and cure the coating film under the conditions of illuminance 50 mW / cm 2 、irradiation dose 0.1 J / cm 2 、oxygen concentration 100 ppm to form layer B, and then wind the laminate of resin layer A and layer B to obtain a film for thin film capacitor. The evaluation results are shown in Table 1.

[0195] (Example 4)

[0196] Use coating solution 2 instead of coating solution 1, and perform the same operations as in Example 3 to obtain a film for thin film capacitor. The evaluation results are shown in Table 1.

[0197] (Example 5)

[0198] Instead of using coating liquid 1, coating liquid 3 was used, and the drying temperature in the drying furnace was 120 °C. Otherwise, the operation was the same as in Example 3, and a film for thin-film capacitors was obtained. The evaluation results are shown in Table 1.

[0199] (Example 6)

[0200] Instead of using coating liquid 1, coating liquid 4 was used. Otherwise, the operation was the same as in Example 3, and a film for thin-film capacitors was obtained. The evaluation results are shown in Table 1.

[0201] (Example 7)

[0202] Instead of using coating liquid 1, coating liquid 5 was used. Otherwise, the operation was the same as in Example 3, and a film for thin-film capacitors was obtained. The evaluation results are shown in Table 1.

[0203] (Example 8)

[0204] 150 g of polyetherimide resin was dissolved in 850 g of N-methyl-2-pyrrolidone to prepare an NMP solution of polyetherimide. It was uniformly coated on a commercially available polyimide film (thickness 140 μm) using a bar coater so that the thickness of the dried polyetherimide layer became 3 μm, and then introduced into a drying furnace at 150 °C and dried for 5 minutes to form a polyetherimide resin layer (resin layer A) on the polyimide film. After uniformly coating coating liquid 6 on 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 0.1 μm, it was dried in a drying furnace at 90 °C for 1 minute. Then, it was introduced into a UV irradiation device, and the coating film was cured under the conditions of illuminance 50 mW / cm 2 , irradiation dose 0.1 J / cm 2 , and oxygen concentration 100 ppm to form layer B. Then, the laminate of resin layer A and layer B was peeled off from the polyimide film and wound to obtain a film for thin-film capacitors. The evaluation results are shown in Table 2.

[0205] (Example 9)

[0206] In the same manner as in Example 8, a polyetherimide resin layer (resin layer A) was formed on a commercially available polyimide film. Coating liquid 7 was coated on resin layer A using a bar coater so that the thickness of the dried layer B became 0.10 μm, and it was dried in a drying furnace at 90 °C for 1 minute to form layer B. Then, the laminate of resin layer A and layer B was peeled off from the polyimide film and wound to obtain a film for thin-film capacitors. The evaluation results are shown in Table 2.

[0207] (Example 10)

[0208] Instead of using coating solution 1, coating solution 9 was used, and otherwise, the operation was the same as in Example 3 to obtain a film for thin film capacitors. The evaluation results are shown in Table 2.

[0209] (Example 11)

[0210] Instead of using PPS film 1, PPS film 2 was used, and instead of using coating solution 1, coating solution 10 was used. Otherwise, the operation was the same as in Example 3 to obtain a film for thin film capacitors. The evaluation results are shown in Table 2.

[0211] (Example 12)

[0212] Instead of using coating solution 1, coating solution 11 was used, the temperature of the drying furnace was changed from 90 °C to 150 °C, and the drying time was changed from 1 minute to 5 minutes. Otherwise, the operation was the same as in Example 3 to obtain a film for thin film capacitors. The evaluation results are shown in Table 2.

[0213] (Example 13)

[0214] 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. It was coated on 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 furnace at 100 °C and dried for 2 minutes to form a cellulose acetate resin layer (resin layer A) on the polyimide film. Next, coating solution 7 was coated on 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 furnace at 100 °C and dried for 1 minute to form layer B on the resin layer A. The laminate of resin layer A and layer B was peeled off from the polyimide film and wound to obtain a film for thin film capacitors. The evaluation results are shown in Table 2.

[0215] (Comparative Example 1)

[0216] The process of forming layer B after forming resin layer A was omitted, and otherwise, the operation was the same as in Example 1 to obtain a film for thin film capacitors composed only of layer A. The evaluation results are shown in Table 3.

[0217] (Comparative Example 2)

[0218] On the corona-treated surface of PPS film 1 (resin layer A), coating solution 8 was coated using a bar coater so that the thickness of the cured layer B became 0.50 μm, and it was dried in an oven at 90 °C for 1 minute to form layer B, obtaining a film for thin film capacitors. The evaluation results are shown in Table 3.

[0219] (Comparative Example 3)

[0220] The PPS film 1 was evaluated as a film for thin film capacitors. The evaluation results are shown in Table 3.

[0221] (Comparative Example 4)

[0222] The PPS film 2 was evaluated as a film for thin film capacitors. The evaluation results are shown in Table 3.

[0223] (Comparative Example 5)

[0224] As a molding material for the resin layer A, polyetherimide resin [product name of SABIC Innovative Plastics: ULTEM 1010-1000-NB (hereinafter abbreviated as "1010-1000")] was prepared. The molding material was placed in a dehumidifying hot air dryer heated to 150 °C [product name of Matsui Seisakusho: Multi Jet MJ3] for 12 hours to be dried. After confirming that the moisture content of the molding material was 300 ppm or less, the molding material was placed in a φ40 mm single screw extrusion molding machine equipped with a T-die having a width of 900 mm for melt kneading. And the melt-kneaded molding material was continuously extruded from the T-die of the single screw extrusion molding machine to extrude and mold a film-shaped polyetherimide resin layer having a length of 1000 m and a width of 65 cm. The barrel temperature of the single screw extrusion molding machine was adjusted to 360 to 380 °C, the temperature of the T-die was adjusted to 385 °C, and the temperature of the connecting pipe connecting the single screw extrusion molding machine and the T-die was adjusted to 380 °C. In addition, when the molding material was charged into the single screw extrusion molding machine, nitrogen gas of 18 L / min as an inert gas was supplied. The formed polyetherimide resin layer was successively wound around a pair of press rollers having a silicone rubber with an arithmetic mean roughness (Ra) of 0.44 to 0.47 μm, a metal roller of a cooling roller at 205 °C having a convex pattern with an arithmetic mean roughness (Ra) of 1.28 μm on the outer peripheral surface, and a 6-inch winding tube located downstream thereof, and was cooled by being clamped between each press roller and the metal roller. By clamping the polyetherimide resin layer between the press roller and the metal roller, a plurality of fine concavo-convex portions were formed on the front and back surfaces of the polyetherimide resin layer, respectively. The obtained polyetherimide resin layer having fine concavo-convex portions on the surface was used as the resin layer A. Dimeric p-xylene was vaporized under the conditions of 180 °C and 10 Pa, thermally decomposed under the conditions of 680 °C and 10 Pa, and the di-radical p-xylene monomer obtained by thermal decomposition was overlapped with the metal roller surface side of the resin layer A under the conditions of 35 °C and 10 Pa, thereby forming a layer B formed of poly-p-xylene resin. The obtained laminate was wound to obtain a film for thin film capacitors. The evaluation results are shown in Table 3.

[0225] (Comparative Example 6)

[0226] The linear polypropylene resin polymerized using a Ziegler-Natta catalyst, having a meso pentad fraction of 0.98, a melting point of 167 °C, and a melt flow rate (MFR) of 2.6 g / 10 min, was fed into a single-screw melt extruder, melt-extruded at 240 °C, and after removing foreign matter with a sintered filter having an 80-μm cutoff, the molten polymer was discharged from a T-die. The molten sheet was pressed onto a casting drum maintained at 95 °C by electrostatic application, and cooled and solidified to obtain an unstretched sheet. Next, the sheet was slowly preheated to 145 °C using a plurality of roll sets, and then passed between rolls maintained at 145 °C and having a circumferential speed difference, and stretched 5.0 times in the longitudinal direction. Next, 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 8% relaxation in the width direction. Further, as the second-stage heat treatment, heat treatment was performed at 140 °C in a state where the width direction was held by a jig. Then, after passing through a cooling step at 100 °C, it was led to the outside of the tenter, the jig at the film end was released, and the film having a thickness of 3.0 μm was wound to obtain a film for thin-film capacitors. The evaluation results are shown in Table 3.

[0227]

[0228]

[0229]

[0230] In addition, for Example 1, Example 2, and Comparative Example 1, films were made in sheet form, and films of sufficient length for capacitor element processing could not be obtained, so capacitor element processing and evaluation of thin-film capacitor characteristics were not performed.

[0231] Industrial Applicability

[0232] The film for thin-film capacitors of the present invention can be applied to various uses such as packaging uses, tape uses, and electrical uses typified by cable sheathing and capacitors. In particular, it can be used for high-voltage capacitor uses that require withstand voltage and reliability at high temperatures.

Claims

1. A film for a thin film capacitor, which has a resin layer A and a resin layer B, the melting point of the resin layer A is 180 °C or higher and / or the glass transition temperature is 130 °C or higher, and the resin layer B with a thickness thinner than that of the resin layer A is provided on at least one outermost layer of the film. The oxygen atom content of the resin layer B is 1.0 mass% or more. When measuring the dynamic friction coefficient between the same surfaces among the two outermost surfaces, if the surface with the larger dynamic friction coefficient is defined as the a surface and the surface with the smaller dynamic friction coefficient is defined as the b surface, and the dynamic friction coefficient between the a surfaces is defined as μdaa, and the dynamic friction coefficient between the a surface and the b surface is defined as μdab, then μdaa > μdab and μdab ≤ 1.

2. The resin layer B satisfies the following condition (i). Condition (i): The value XB calculated based on the following formula (Ⅱ) 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 resin layer B is 0.80 or less. Formula (Ⅱ) XB = (atomic fraction of carbon atom C in the resin layer B + atomic fraction of nitrogen atom N in the resin layer B + atomic fraction of sulfur atom S in the resin layer B + atomic fraction of silicon atom Si in the resin layer B) / (atomic fraction of hydrogen atom H in the resin layer B + atomic fraction of oxygen atom O in the resin layer B).

2. A film for a thin film capacitor, which has a resin layer A and a resin layer B, the melting point of the resin layer A is 180 °C or higher and / or the glass transition temperature is 130 °C or higher, and the resin layer B with a thickness thinner than that of the resin layer A is provided on at least one outermost layer of the film. The oxygen atom content of the resin layer B is 1.0 mass% or more. The resin layer B satisfies the following condition (i). Condition (i): The value XB calculated based on the following formula (Ⅱ) 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 resin layer B is 0.80 or less. Formula (Ⅱ) XB = (atomic fraction of carbon atom C in the resin layer B + atomic fraction of nitrogen atom N in the resin layer B + atomic fraction of sulfur atom S in the resin layer B + atomic fraction of silicon atom Si in the resin layer B) / (atomic fraction of hydrogen atom H in the resin layer B + atomic fraction of oxygen atom O in the resin layer B).

3. The film for a thin film capacitor according to claim 1 or 2, wherein the dielectric loss tangent is 2.0% or less.

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

5. The film for a thin film capacitor according to claim 1 or 2, wherein the resin layer B satisfies the following condition (i). Condition (i): The value XB calculated based on the following formula (Ⅱ) 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 resin layer B is 0.70 or less. XB in formula (II) = (atomic fraction of carbon atom C in resin layer B + atomic fraction of nitrogen atom N in resin layer B + atomic fraction of sulfur atom S in resin layer B + atomic fraction of silicon atom Si in resin layer B) / (atomic fraction of hydrogen atom H in resin layer B + atomic fraction of oxygen atom O in resin layer B).

6. The film for thin film capacitor according to claim 1 or 2, wherein the load area ratio Smr1 for separating the protruding peak portion from the central portion on at least one outermost surface satisfies Smr1 ≥ 12%.

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

8. The film for thin film capacitor according to claim 1 or 2, when the film thickness is set to T(F), the maximum valley depth Sv of both outermost surfaces satisfies Sv / T(F) < 0.

30.

9. The film for thin film capacitor according to claim 1 or 2, wherein the resin layer B contains two or more incompatible components.

10. The film for thin film capacitor according to claim 1 or 2, wherein the resin layer A contains at least one resin selected from polyphenylene sulfide resin, polyetherimide resin, polyphenylsulfone resin, and polyethersulfone resin in an amount of 50% by mass or more and 100% by mass or less.

11. The film for thin film capacitor according to claim 1 or 2, wherein the resin layer B contains at least one resin selected from acrylic resin, epoxy resin, cellulose derivative, and polyester resin in an amount of 50% by mass or more and 100% by mass or less.

12. A metal laminated film for thin film capacitor, which has a metal layer on at least one outermost surface of the film for thin film capacitor according to any one of claims 1 to 11.

13. The metal laminated film for thin film capacitor according to claim 12, which has the resin layer A, the resin layer B, and the metal layer in sequence.

14. The metal laminated film for thin film capacitor according to claim 13, having the resin layer B only on one surface of the resin layer A, having the metal layer on the resin layer B side, and when the surface with a larger kinetic friction coefficient measured with the same surface is set as the a surface and the surface with a smaller kinetic friction coefficient is set as the b surface among the two outermost surfaces, the b surface is on the resin layer B side as viewed from the resin layer A.

15. A thin film capacitor, which is made using the metal laminated film for thin film capacitor according to any one of claims 12 to 14.

Images