There is provided a double-sided copper-clad laminate for forming a capacitor that can exhibit excellent properties in voltage endurance and peel strength, while ensuring high capacitor capacity, when used as a capacitor. This double-sided copper-clad laminate includes an adhesive layer and a copper foil in order on each of both surfaces of a resin film, the resin film is in a cured state at 25° C., and each of the copper foils has a maximum peak height Sp of 0.05 μm or more and 3.3 μm or less as measured in accordance with ISO 25178 on a surface on a side being in contact with the adhesive layer.

The invention provides a film having a high relative permittivity, a high volume resistivity, and a high breakdown strength. The film has a relative permittivity of 9 or higher at a frequency of 1 kHz and 30° C., a volume resistivity of 5E+15 Ω.Math.cm or higher at 30° C., and a breakdown strength of 500 V/μm or higher.

The invention provides a film having a high relative permittivity, a high volume resistivity, and a high breakdown strength. The film has a relative permittivity of 9 or higher at a frequency of 1 kHz and 30° C., a volume resistivity of 5E+15 Ω.Math.cm or higher at 30° C., and a breakdown strength of 500 V/μm or higher.

A polypropylene film in which: during a heating process in thermomechanical analysis (TMA), the relationship (Ts−Tf)≤40° C. is satisfied by the temperature (Ts) (° C.) at which the film contracts by 0.1% in the longitudinal direction and the temperature (Tf) (° C.) at which the longitudinal shrink stress reaches 0.01 MPa; and the skewness (Ssk), which is the degree of bias of the protrusion shape, of at least one surface of the film is greater than −30 and less than 5. Thus provided is a polypropylene film that has excellent reliability and withstand voltage characteristics in high temperature environments when used in high voltage capacitors, that has a structure with excellent stability against heat and is suitable for applications in capacitors or the like to be used at high temperatures and high voltages, and that has excellent processability and does not wrinkle during a conveyance process including a vapor deposition process.

The present invention addresses the problem of providing a film for a film capacitor that has high heat resistance, self-healing properties, and excellent productivity, wherein the film has a resin layer A having a melting point of 180° C. or higher and/or a glass transition temperature of 130° C. or higher and a layer B thinner than the resin layer A in at least the outermost layer of the film, the oxygen content of the layer B is 1.0% by mass or more, when a dynamic friction coefficient is measured on the same surface of two outermost layer surfaces, the surface having a higher dynamic friction coefficient is defined as an a-plane and the surface having a smaller dynamic friction coefficient is defined as a b-plane, and when a dynamic friction coefficient between the a-planes is defined as μdaa, and a dynamic friction coefficient between the a-plane and the b-plane is defined as μdab, μdaa>μdab and μdab≤1.2 are satisfied.

The present invention addresses the problem of providing a film for a film capacitor that has high heat resistance, self-healing properties, and excellent productivity, wherein the film has a resin layer A having a melting point of 180° C. or higher and/or a glass transition temperature of 130° C. or higher and a layer B thinner than the resin layer A in at least the outermost layer of the film, the oxygen content of the layer B is 1.0% by mass or more, when a dynamic friction coefficient is measured on the same surface of two outermost layer surfaces, the surface having a higher dynamic friction coefficient is defined as an a-plane and the surface having a smaller dynamic friction coefficient is defined as a b-plane, and when a dynamic friction coefficient between the a-planes is defined as μdaa, and a dynamic friction coefficient between the a-plane and the b-plane is defined as μdab, μdaa>μdab and μdab≤1.2 are satisfied.

A method for preparing a modified polypropylene film, the modified polypropylene film comprising a polypropylene film; and, an oxide layer and/or nitride layer, each of which has a thickness of 20-500 nm, on a surface of the polypropylene film; the method comprising: depositing the oxide layer or nitride layer on a surface of the polypropylene film by an Atomic Layer Deposition (ALD) process to obtain the modified polypropylene film; wherein the step of depositing the oxide layer or nitride layer comprises: placing the polypropylene film in an ALD reaction chamber; vacuumizing; heating up; introducing a carrier gas; and, passing at least two precursors into the reaction chamber alternately for reaction, resulting in the modified polypropylene film; wherein the precursors comprise a precursor for providing a metal element or Si, and a precursor for providing an oxygen or nitrogen element.

Capacitor comprising: a first porous semiconductor having an average pore size of between 20 nm and 200 nm and preferably between 40 nm and 100 nm, at least one second electric conductor, wherein the second electric conductor infiltrates the porous structure, and the materials involved are selected such that a potential barrier is formed between the first porous semiconductor and the second conductor, without applying an external voltage, as a result of the diffusion of charge carriers, which is preferably more than 0.5 V, more preferably more than 0.7 V, more preferably more than 1 V, and more preferably still more than 1.4 V, wherein a dielectric layer having a thickness of 1 nm to 10 nm is preferably arranged between the first porous semiconductor and the second electric conductor.

A film capacitor includes: a main body portion including a first metallized film including a first metal film on a first face of a first dielectric film, and a second metallized film including a second metal film on a second face of a second dielectric film; and external electrodes. The first or second dielectric film is located between the first and second metal films. The external electrodes are disposed on main body ends so as to be electrically connected with the first or second metal film. At least one of the first and second metal films includes a first portion which has a film thickness of 20 nm or more and is located in proximity to the main body ends, and the first portion includes a first groove extending in the first direction and being in contact with corresponding one of the main body ends.

A polypropylene film which is capable of suppressing blocking in a rolled polypropylene film. The polypropylene film has a first surface and a second surface, contains a polypropylene resin as a main component, and is configured such that: the Svk value (SvkA) of the first surface is 0.005 μm or more and 0.030 μm or less; the Spk value (SpkA) of the first surface is more than 0.035 μm and 0.080 μm or less; the Svk value (SvkB) of the second surface is 0.005 μm or more and 0.030 μm or less; and the Spk value (SpkB) of the second surface is 0.015 μm or more and 0.035 μm or less.