JP2022045539A - Film capacitor and film for film capacitor - Google Patents

Abstract

To provide a film capacitor that includes a resin film, of which the slipperiness and withstand voltage strength are high.SOLUTION: A film capacitor 100 comprises a dielectric film 110, and a metal layer 120 provided on at least one surface of the dielectric film 110. The dielectric film 110 is composed of a resin film 20 having a first surface 11 and a second surface 12 in the thickness direction. The resin film 20 includes a first rein layer 21 and a second resin layer 22 one surface of which constitutes the first surface 11 of the resin film 20. The second resin layer 22 contains a plurality of first particles 31. Assuming that D1 represents the particle diameter of first particles 31 existing on the first surface 11 of the resin film 20, L1 represents a particle-to-particle distance and σ1 represents the standard deviation of the particle-to-particle distance, the ratio L1/D1 of the particle-to-particle distance L1 to the particle diameter D1 is 3.5 to 15 inclusive, and the ratio σ1/D1 of the standard deviation σ1 of the particle-to-particle distance to the particle diameter D1 is 1.0 to 8.0 inclusive.SELECTED DRAWING: Figure 2

Description

The present invention relates to a film capacitor and a film for a film capacitor.

As a kind of capacitor, there is a film capacitor having a structure in which a first metal layer and a second metal layer facing each other across the resin film are arranged while using a flexible resin film as a dielectric. Such film capacitors include, for example, a first dielectric film on which a first metal layer made of aluminum or the like is formed, and a second dielectric film on which a second metal layer made of aluminum or the like is formed. Is made by winding or laminating.

Not limited to the dielectric film of the film capacitor, if the surface of the resin film is smooth, the slipperiness becomes low, which makes it difficult to handle and reduces workability in the processes of transporting, winding, processing, etc. of the resin film. It becomes a factor to do. For example, when a film capacitor is manufactured by winding a first dielectric film on which a first metal layer is formed and a second dielectric film on which a second metal layer is formed, a film is formed. In some cases, the winding body of the film is pressed to be processed into a flat shape, but if the slipperiness of the resin film is low, it becomes difficult to process the winding body of the film.

In order to improve the slipperiness of the resin film, a method of adding particles to the resin film to provide irregularities on the surface of the resin film is performed.

Patent Document 1 contains particles and a resin, and is a particle array film in which particles are arranged to form convex portions. The particle size of the particles is D, the height of the convex portions is H, and the distance between particles is L. When the standard deviation of the distance between particles is σ, the particle size D is 50 to 300 nm, the height H of the convex portion is 50 to 200 nm, and the ratio H / D of the height of the convex portion and the particle size is 0. It is .2 to 1.0, the ratio L / D of the particle distance to the particle size is 1.05 to 3, and the standard deviation of the particle distance to the particle size ratio σ / D is 0.4 or less. , The following equation (1) L√N (1)
(In the formula, L indicates the distance between particles [nm], and N indicates the number density of particles [1 / nm ² ].)
A particle array film characterized in that the value represented by is 0.75 or more is disclosed.

Japanese Unexamined Patent Publication No. 2018-185458

When considering the use as a film for a film capacitor, slipperiness can be imparted by adding particles to the resin film, but on the other hand, since the resin film contains particles that become impurities, it is resistant. It causes a decrease in voltage strength.

The particle array film described in Patent Document 1 is preferably used as an antireflection film, and is said to be excellent in antireflection property, transparency, scratch resistance and masking resistance. However, Patent Document 1 does not describe the use as a film for a film capacitor, and does not describe slipperiness or withstand voltage strength.

An object of the present invention is to provide a film capacitor including a dielectric film made of a resin film having high slipperiness and withstand voltage strength. Furthermore, an object of the present invention is to provide a film for a film capacitor used as a dielectric film of the film capacitor.

The film capacitor of the present invention includes a dielectric film and a metal layer provided on at least one surface of the dielectric film. The dielectric film is composed of a resin film having a first surface and a second surface facing each other in the thickness direction. The resin film includes a first resin layer and a second resin layer whose one surface constitutes the first surface of the resin film. The second resin layer contains a plurality of first particles.

In the first aspect, the film capacitor of the present invention has a particle diameter of D1, an interparticle distance of L1, and a standard deviation of the interparticle distance of σ1 of the first particles existing on the first surface of the resin film. When, the ratio L1 / D1 of the interparticle distance L1 to the particle diameter D1 is 3.5 or more and 15 or less, and the ratio σ1 / D1 of the standard deviation σ1 of the interparticle distance to the particle diameter D1 is 1. It is 0 or more and 8.0 or less.

In the second aspect, the film capacitor of the present invention has the above particle diameter D1 with respect to the particle diameter D1 when the particle diameter of the first particles existing on the first surface of the resin film is D1 and the interparticle distance is L1. The ratio L1 / D1 of the interparticle distance L1 is 3.5 or more and 15 or less.

In the third aspect, the film capacitor of the present invention has the particle diameter of the first particles existing on the first surface of the resin film, where the particle diameter is D1 and the standard deviation of the interparticle distance is σ1. The ratio σ1 / D1 of the standard deviation σ1 of the interparticle distance to D1 is 1.0 or more and 8.0 or less.

The film for a film capacitor of the present invention is composed of a resin film having a first surface and a second surface facing each other in the thickness direction. The resin film includes a first resin layer and a second resin layer whose one surface constitutes the first surface of the resin film. The second resin layer contains a plurality of first particles.

In the first aspect, the film for a film capacitor of the present invention has a particle diameter of D1, an interparticle distance of L1, and a standard deviation of the interparticle distance of the first particles existing on the first surface of the resin film. When σ1, the ratio L1 / D1 of the interparticle distance L1 to the particle diameter D1 is 3.5 or more and 15 or less, and the ratio σ1 / D1 of the standard deviation σ1 of the interparticle distance to the particle diameter D1 is It is 1.0 or more and 8.0 or less.

In the second aspect, the film for a film capacitor of the present invention has the particle diameter D1 when the particle diameter of the first particles existing on the first surface of the resin film is D1 and the interparticle distance is L1. The ratio L1 / D1 of the interparticle distance L1 to the above is 3.5 or more and 15 or less.

In the third aspect, the film for a film capacitor of the present invention is described above, where the particle size of the first particles existing on the first surface of the resin film is D1 and the standard deviation of the interparticle distance is σ1. The ratio σ1 / D1 of the standard deviation σ1 of the interparticle distance to the particle diameter D1 is 1.0 or more and 8.0 or less.

According to the present invention, it is possible to provide a film capacitor including a dielectric film made of a resin film having high slipperiness and withstand voltage strength.

FIG. 1 is a cross-sectional view schematically showing an example of the film capacitor of the present invention. FIG. 2 is a cross-sectional view schematically showing an example of the film for a film capacitor of the present invention. FIG. 3 is a plan view schematically showing an example of the surface of the second resin layer of the film for a film capacitor of the present invention. FIG. 4 is a cross-sectional view schematically showing still another example of the resin film of the present invention.

Hereinafter, the film capacitor of the present invention and the film for a film capacitor will be described.
However, the present invention is not limited to the following configuration, and can be appropriately modified and applied without changing the gist of the present invention. A combination of two or more of the individual desirable configurations of the invention described below is also the invention.

[Film capacitor]
The film capacitor of the present invention includes a dielectric film and a metal layer provided on at least one surface of the dielectric film.

Hereinafter, as an embodiment of the film capacitor of the present invention, a first dielectric film provided with a first metal layer and a second dielectric film provided with a second metal layer are laminated. A winding type film capacitor, which is wound in a state, will be described as an example. The film capacitor of the present invention is a laminated film capacitor in which a first dielectric film provided with a first metal layer and a second dielectric film provided with a second metal layer are laminated. And so on. Further, in the film capacitor of the present invention, a first dielectric film provided with a first metal layer and a second metal layer and a second dielectric film not provided with a metal layer are wound or wound. It may be a laminated film capacitor or the like.

FIG. 1 is a cross-sectional view schematically showing an example of the film capacitor of the present invention.
The film capacitor 100 shown in FIG. 1 is a winding type film capacitor. The film capacitor 100 has a first metallized film 130 provided with a first metal layer 120 on one surface of the first dielectric film 110 and a second film capacitor 100 on one surface of the second dielectric film 140. The second metallized film 160 provided with the metal layer 150 of the above is wound by being wound in a laminated state. The film capacitor 100 further includes a first external terminal electrode 170 electrically connected to the first metal layer 120 and a second external terminal electrode 180 electrically connected to the second metal layer 150. It is equipped with.

The first metal layer 120 is formed so as to reach one side edge of the first metallized film 130 but not the other side edge. On the other hand, the second metal layer 150 is formed so as not to reach one side edge of the second metallized film 160 but to reach the other side edge. The first metal layer 120 and the second metal layer 150 are composed of, for example, aluminum, zinc, and the like.

The first metallized film 130 and the second metallized film 160 are wound into a stacked state. As shown in FIG. 1, the end of the first metal layer 120 on the side reaching the side edge of the first metallized film 130, and the second metallized film 160 in the second metal layer 150. The first metallized film 130 and the second metallized film 160 are displaced from each other in the width direction so that both the end portions on the side reaching the side edge of the metallised film are exposed.

In the film capacitor 100 shown in FIG. 1, the first metallized film 130 is located outside the second metallized film 160, and the first metallized film 130 and the second metallized film 160 are respectively. The first metal layer 120 and the second metal layer 150 are each wound so as to face inward.

The first external terminal electrode 170 and the second external terminal electrode 180 are formed by spraying, for example, zinc or the like onto each end surface of the capacitor body obtained as described above. The first external terminal electrode 170 is in contact with the exposed end of the first metal layer 120, thereby being electrically connected to the first metal layer 120. On the other hand, the second external terminal electrode 180 comes into contact with the exposed end of the second metal layer 150, thereby being electrically connected to the second metal layer 150.

It is preferable that the film capacitor of the present invention is pressed into a flat shape such as an ellipse or an oval in cross-sectional shape, and has a more compact shape than when the cross-sectional shape is a perfect circle. The film capacitor of the present invention may include a cylindrical winding shaft. The winding shaft is arranged on the central axis of the metallized film in the wound state, and serves as a winding shaft when winding the metallized film.

In the film capacitor of the present invention, a fuse portion may be provided on the metal layer. The fuse portion means a portion connecting the electrode portion and the electrode portion in which the metal layer serving as the counter electrode is divided into a plurality of portions. The pattern of the metal layer having the fuse portion is not particularly limited, and for example, the electrode patterns disclosed in JP-A-2004-363431 and JP-A-5-251266 can be used.

In the film capacitor of the present invention, the film for a film capacitor of the present invention is used as the dielectric film. In the film capacitor of the present invention, a metal layer is provided on at least one surface of the resin film constituting the film for the film capacitor of the present invention. In the film capacitor of the present invention, when the metal layer is provided on one surface of the resin film, the metal layer may be provided on the first surface of the resin film, or the metal layer may be provided on the second surface of the resin film. You may. In the film capacitor of the present invention, it is preferable that the metal layer is provided on the first surface of the resin film, that is, on the surface of the second resin layer.

For example, in the film capacitor 100 shown in FIG. 1, the film for a film capacitor of the present invention may be used for both the first dielectric film 110 and the second dielectric film 140, or only one of them. The film for a film capacitor of the present invention may be used. In the film capacitor of the present invention, when the film for the film capacitor of the present invention is used for both the first dielectric film and the second dielectric film, the film for the film capacitor of the same embodiment may be used for both. However, films for film capacitors of different aspects may be used.

[Film for film capacitors]
FIG. 2 is a cross-sectional view schematically showing an example of the film for a film capacitor of the present invention. The thickness of the first resin layer 21 and the second resin layer 22 and the size, number, arrangement, etc. of the first particles 31 shown in FIG. 2 have been appropriately changed for the sake of clarity and simplification of the drawings. There is. The same applies to other drawings.

The film capacitor 1 shown in FIG. 2 is composed of a resin film 20 having a first surface 11 and a second surface 12 facing each other in the thickness direction (vertical direction in FIG. 2). The resin film 20 includes a first resin layer 21 and a second resin layer 22. In the film capacitor 1, one surface of the second resin layer 22 constitutes the first surface 11 of the resin film 20, and one surface of the first resin layer 21 constitutes the second surface 12 of the resin film 20. ..

In the example shown in FIG. 2, the second resin layer 22 is provided on the surface of the first resin layer 21. In this case, the second resin layer 22 may be provided on the entire surface of the first resin layer 21, or may be provided on a part of the surface of the first resin layer 21. The first resin layer 21 and the second resin layer 22 may not be in contact with each other, and for example, another resin layer may be present between the first resin layer 21 and the second resin layer 22. ..

FIG. 3 is a plan view schematically showing an example of the surface of the second resin layer of the film for a film capacitor of the present invention.

As shown in FIGS. 2 and 3, the second resin layer 22 contains a plurality of first particles 31. The first particles 31 are present on the first surface 11 of the resin film 20. That is, the first particles 31 are present on the surface of the second resin layer 22. As shown in the example shown in FIG. 2, the first particles 31 are preferably exposed on the first surface 11 of the resin film 20, and more preferably protruding from the first surface 11 of the resin film 20. That is, the first particles 31 are preferably exposed on the surface of the second resin layer 22, and more preferably protruding from the surface of the second resin layer 22. The first particles 31 that are not exposed on the first surface 11 of the resin film 20 and are buried in the second resin layer 22 may be contained. The first particle 31 may or may not be in contact with the first resin layer 21. Further, a part of the first particles 31 may be buried in the first resin layer 21. The sizes of the first particles 31 may be the same or different.

When the particle size of the first particles 31 existing on the first surface 11 of the resin film 20 is D1 (see FIG. 3) and the interparticle distance is L1 (see FIG. 3), the interparticle distance L1 with respect to the particle size D1 The ratio L1 / D1 is 3.5 or more and 15 or less. When the ratio L1 / D1 of the interparticle distance L1 to the particle diameter D1 is 15 or less, the first particles 31 are arranged on the surface of the second resin layer 22 at a close distance, so that the slipperiness of the resin film 20 is high. Become. On the other hand, if the first particles 31 are too close to each other, the withstand voltage strength is lowered when used in a film capacitor. Therefore, the ratio L1 / D1 of the interparticle distance L1 to the particle diameter D1 needs to be 3.5 or more. There is.

When the particle diameter of the first particles 31 existing on the first surface 11 of the resin film 20 is D1 and the standard deviation of the interparticle distance is σ1, the ratio of the standard deviation σ1 of the interparticle distance to the particle diameter D1 σ1 / D1 Is 1.0 or more and 8.0 or less. When the ratio σ1 / D1 of the standard deviation σ1 of the interparticle distance to the particle diameter D1 is 8.0 or less, the first particles 31 are uniformly arranged on the surface of the second resin layer 22, and the resin film 20 slips. The sex becomes high. On the other hand, if the first particles 31 segregate, the withstand voltage strength is lowered when used in a film capacitor. Therefore, the ratio σ1 / D1 of the standard deviation σ1 of the interparticle distance to the particle diameter D1 is 1.0 or more. There is a need.

As described above, the ratio L1 / D1 of the interparticle distance L1 to the particle diameter D1 is 3.5 or more and 15 or less, and the ratio σ1 / D1 of the standard deviation σ1 of the interparticle distance to the particle diameter D1 is 1.0. By satisfying at least one of the above 8.0 or less, the slipperiness and withstand voltage strength of the resin film can be increased. In particular, the ratio L1 / D1 of the interparticle distance L1 to the particle diameter D1 is 3.5 or more and 15 or less, and the ratio σ1 / D1 of the standard deviation σ1 of the interparticle distance to the particle diameter D1 is 1.0 or more and 8. It is preferably 0 or less.

The particle diameter D1 of the first particles 31 existing on the first surface 11 of the resin film 20 is measured by the following method.
First, an image of the surface of the second resin layer 22 as shown in FIG. 3 is taken using a scanning electron microscope (SEM). From the photographed surface image, 30 first particles 31 existing on the first surface 11 of the resin film 20, that is, the surface of the second resin layer 22, are randomly extracted. The particle size of each particle is obtained, and the average value is D1. The diameter corresponding to the circle of the particles observed from the photographed surface image is defined as the particle diameter.

The interparticle distance L1 of the first particles 31 existing on the first surface 11 of the resin film 20 is measured by the following method.
First, using SEM, an image of the surface of the second resin layer 22 as shown in FIG. 3 is taken. From the photographed surface image, 50 sets of adjacent first particles 31 in the second resin layer 22 are randomly extracted, the distance between each particles is obtained, and the average value is L1. The adjacent particles refer to a state in which no other particle exists between the two particles.

In the present specification, when an image of the surface of the second resin layer 22 is taken under the following conditions, the particle diameter D1 and the interparticle distance L1 of the first particles 31 observed on the surface of the second resin layer 22 are measured. do. Therefore, the first particles 31 for measuring the particle diameter D1 and the inter-particle distance L1 do not necessarily have to be exposed on the surface of the second resin layer 22.
Equipment: JEOL (JSM7100F manufactured by JEOL Ltd.)
Tube voltage: 15kV
Irradiation current: 8mA

The standard deviation σ1 of the interparticle distance of the first particles 31 existing on the first surface 11 of the resin film 20 is obtained from the interparticle distances of 50 sets of the first particles 31 when determining the interparticle distance L1 and their average values. Calculated.

The first particles 31 are preferably inorganic particles, and preferably silica particles.

The first resin layer 21 may contain a curable resin as a main component or a thermoplastic resin as a main component.

As used herein, the term "main component" means a component having the largest weight percentage, preferably a component having a weight percentage of more than 50% by weight. Therefore, the first resin layer 21 may contain, for example, an additive such as a silicone resin or an uncured portion of a starting material such as a first organic material and a second organic material, which will be described later, as a component other than the main component.

The curable resin may be a thermosetting resin or a photocurable resin.
In the present specification, the thermosetting resin means a resin that can be cured by heat, and does not limit the curing method. Therefore, as long as the resin can be cured by heat, the thermosetting resin also includes a resin cured by a method other than heat (for example, light, electron beam, etc.). Further, depending on the material, the reaction may be started depending on the reactivity of the material itself, and a thermosetting resin is also used if the curing proceeds without necessarily applying heat or light from the outside. The same applies to the photocurable resin, and the curing method is not limited.

When the first resin layer 21 contains a curable resin as a main component, the curable resin is, for example, a cured product of a first organic material and a second organic material. In this case, the curable resin is composed of a cured product obtained by reacting a hydroxyl group (OH group) of the first organic material with an isocyanate group (NCO group) of the second organic material.

When a cured product is obtained by the above reaction, an uncured portion of the starting material may remain in the first resin layer 21. For example, the first resin layer 21 may contain at least one of a hydroxyl group and an isocyanate group. In this case, the first resin layer 21 may contain either a hydroxyl group or an isocyanate group, or may contain both a hydroxyl group and an isocyanate group.
The presence of hydroxyl groups and / or isocyanate groups can be confirmed using a Fourier transform infrared spectrophotometer (FT-IR).

As the first organic material, for example, a phenoxy resin is used. As the first organic material, polyvinyl acetal (PVAA) resin, polyvinyl butyral (PVB) resin, acrylic resin, epoxy resin and the like may be used.

As the second organic material, for example, diphenylmethane diisocyanate (MDI), an MDI modified product, or a mixture of MDI and an MDI modified product is used. As the second organic material, toluene diisocyanate (TDI), a TDI modified product, or a mixture of TDI and a TDI modified product may be used.

Further, among the above-mentioned first organic material and second organic material, the first resin layer 21 may be produced by using only the first organic material which is a thermoplastic resin without using the second organic material.

The first resin layer 21 may also contain additives for adding other functions. For example, smoothness can be imparted by adding a leveling agent. More preferably, the additive is a material that has a functional group that reacts with a hydroxyl group and / or an isocyanate group and forms a part of the crosslinked structure of the cured product. Examples of such a material include a resin having at least one functional group selected from the group consisting of a hydroxyl group, an epoxy group, a silanol group and a carboxyl group.

The thickness T1 of the first resin layer 21 is not particularly limited, but is preferably 0.5 μm or more and 10 μm or less.
The thickness T1 of the first resin layer 21 can be measured using an optical film thickness meter. Similarly, the thickness T2 of the second resin layer 22 or the thickness T3 of the third resin layer 23, which will be described later, can be measured using an optical film thickness meter.

The second resin layer 22 may contain a curable resin as a main component or a thermoplastic resin as a main component. The curable resin may be a thermosetting resin or a photocurable resin.

The second resin layer 22 can be made, for example, by using a mixture of the first organic material and the first particles.

As the first organic material, for example, a phenoxy resin is used. As the first organic material, PVAA resin, PVB resin, acrylic resin, epoxy resin and the like may be used.

The second organic material may be mixed with the first organic material described above. As the second organic material, for example, MDI, MDI modified product, a mixture of MDI and MDI modified product, TDI, TDI modified product, or a mixture of TDI and TDI modified product is used.

The thickness T2 of the second resin layer 22 is not particularly limited, but the ratio (T2 / D1) of the thickness T2 of the second resin layer 22 to the particle diameter D1 of the first particles 31 is 0.5 or more and 1 or less. Is preferable. The thickness T2 of the second resin layer 22 referred to here means the thickness measured at a position where the first particles 31 do not protrude from the surface.

FIG. 4 is a cross-sectional view schematically showing still another example of the resin film of the present invention.
In the film capacitor film 2 shown in FIG. 4, the resin film 20 further includes a third resin layer 23. In the film capacitor 2 for film capacitors, one surface of the second resin layer 22 constitutes the first surface 11 of the resin film 20, and one surface of the third resin layer 23 constitutes the second surface 12 of the resin film 20. ..

In the example shown in FIG. 4, the third resin layer 23 is provided on the surface of the first resin layer 21. In this case, the third resin layer 23 may be provided on the entire surface of the first resin layer 21, or may be provided on a part of the surface of the first resin layer 21. The first resin layer 21 and the third resin layer 23 may not be in contact with each other, and for example, another resin layer may be present between the first resin layer 21 and the third resin layer 23. ..

The third resin layer 23 contains a plurality of second particles 32. The second particles 32 are present on the second surface 12 of the resin film 20. That is, the second particles 32 are present on the surface of the third resin layer 23. As shown in the example shown in FIG. 4, the second particle 32 is preferably exposed on the second surface 12 of the resin film 20, and more preferably protrudes from the second surface 12 of the resin film 20. That is, the second particles 32 are preferably exposed on the surface of the third resin layer 23, and more preferably protrude from the surface of the third resin layer 23. It should be noted that the second particles 32 that are not exposed on the second surface 12 of the resin film 20 and are buried in the third resin layer 23 may be contained. The second particle 32 may or may not be in contact with the first resin layer 21. Further, a part of the second particles 32 may be buried in the first resin layer 21. The size of the second particle 32 may be the same or different.

When the particle diameter of the second particles 32 existing on the second surface 12 of the resin film 20 is D2 (not shown) and the interparticle distance is L2 (not shown), the interparticle distance L2 with respect to the particle diameter D2 The ratio L2 / D2 is preferably 3.5 or more and 15 or less. The ratio L2 / D2 of the interparticle distance L2 to the particle diameter D2 may be the same as or different from the ratio L1 / D1 of the interparticle distance L1 to the particle diameter D1.

When the particle size of the second particle 32 existing on the second surface 12 of the resin film 20 is D2 and the standard deviation of the interparticle distance is σ2, the ratio σ2 / D2 of the standard deviation σ2 of the interparticle distance to the particle size D2 Is preferably 1.0 or more and 8.0 or less. The ratio σ2 / D2 of the standard deviation σ2 of the interparticle distance to the particle size D2 may be the same as or different from the ratio σ1 / D1 of the standard deviation σ1 of the interparticle distance to the particle size D1.

The ratio L2 / D2 of the interparticle distance L2 to the particle size D2 is 3.5 or more and 15 or less, and the ratio σ2 / D2 of the standard deviation σ2 of the interparticle distance to the particle size D2 is 1.0 or more and 8.0. By satisfying at least one of the following, the slipperiness and withstand voltage strength of the resin film can be further increased. In particular, the ratio L2 / D2 of the interparticle distance L2 to the particle size D2 is 3.5 or more and 15 or less, and the ratio σ2 / D2 of the standard deviation σ2 of the interparticle distance to the particle size D2 is 1.0 or more and 8. It is preferably 0 or less.

The particle diameter D2 of the second particle 32 is measured by the same method as the particle diameter D1 of the first particle 31. The interparticle distance L2 of the second particle 32 is measured by the same method as the interparticle distance L1 of the first particle 31. The standard deviation σ2 of the interparticle distance of the second particle 32 is calculated by the same method as the standard deviation σ1 of the interparticle distance of the first particle 31.

The second particle 32 is preferably an inorganic particle, and preferably a silica particle. The material constituting the second particle 32 may be different from the material constituting the first particle 31, but is preferably the same.

The third resin layer 23 can be manufactured by using the same material as the second resin layer 22.

The thickness T3 of the third resin layer 23 is not particularly limited, but the ratio (T3 / D2) of the thickness T3 of the third resin layer 23 to the particle diameter D2 of the second particles 32 is 0.5 or more and 1 or less. Is preferable. The thickness T3 of the third resin layer 23 referred to here means the thickness measured at a position where the second particles 32 do not protrude from the surface. The thickness T3 of the third resin layer 23 may be the same as or different from the thickness T2 of the second resin layer 22.

[Manufacturing method of film for film capacitors]
Hereinafter, an example of a method for manufacturing a film for a film capacitor of the present invention will be described.

First, the first resin solution is applied to the base film. Preferably, after applying the first resin solution to the base film, hot air is blown to dry the solvent. As a result, the first resin layer 21 is formed.

As the base film, for example, a polyethylene terephthalate (PET) film or the like can be used.

The first resin solution is prepared, for example, by dissolving the above-mentioned first organic material and second organic material in a solvent, mixing them, and adding additives as necessary. The weight ratio of the first organic material to the second organic material (first organic material / second organic material) is preferably 50/50 or more and 75/25 or less. The first resin solution may be prepared by dissolving only the first organic material among the first organic material and the second organic material in a solvent and mixing them, and adding an additive if necessary. The solvent contained in the first resin solution may be present as a residue in the first resin layer 21 after curing.

As the solvent, methyl ethyl ketone (MEK), tetrahydrofuran (THF) and the like can be used. These solvents may be used alone or in combination of two or more. Above all, it is preferable to use a mixed solvent containing MEK and THF. The weight ratio of MEK to THF (MEK / THF) is preferably 15/85 or more and 85/15 or less.

Next, the second resin solution is applied to the first resin layer 21 on the base film. Preferably, after applying the second resin solution to the first resin layer 21, hot air is applied to dry the solvent. As a result, the second resin layer 22 is formed.

The second resin solution is prepared, for example, by dissolving the above-mentioned first organic material and the first particles in a solvent, mixing them, and adding an additive as necessary. A second organic material may be mixed with the second resin solution. The solvent contained in the second resin solution may be present as a residue in the second resin layer 22 after curing.

As the solvent, MEK, THF and the like can be used. These solvents may be used alone or in combination of two or more. Above all, it is preferable to use a mixed solvent containing MEK and THF. The weight ratio of MEK to THF (MEK / THF) is preferably 15/85 or more and 85/15 or less.

The two-layer film including the first resin layer 21 and the second resin layer 22 is peeled off from the base film.

If necessary, a third resin solution is applied to the surface of the first resin layer 21 opposite to the second resin layer 22. Preferably, after applying the third resin solution to the first resin layer 21, hot air is applied to dry the solvent. As a result, the third resin layer 23 may be formed.

The third resin solution is prepared, for example, by dissolving the above-mentioned first organic material and the second particles in a solvent, mixing them, and adding an additive if necessary. The second organic material may be mixed with the third resin solution. The solvent contained in the third resin solution may be present as a residue in the third resin layer 23 after curing.

As the solvent, MEK, THF and the like can be used. These solvents may be used alone or in combination of two or more. Above all, it is preferable to use a mixed solvent containing MEK and THF. The weight ratio of MEK to THF (MEK / THF) is preferably 15/85 or more and 85/15 or less.

Then, the two-layer or three-layer film is heat-treated to cure the resin. As described above, the resin film constituting the film for the film capacitor of the present invention can be obtained. It is also possible to produce a resin film having a structure of four or more layers by the same method.

[Manufacturing method of film capacitors]
Hereinafter, an example of a method for manufacturing a film capacitor using the film for a film capacitor of the present invention will be described.

First, a metallized film is obtained by forming a metal layer on at least one surface of the resin film constituting the film for a film capacitor of the present invention. For example, in the case of a resin film having a two-layer structure including a first resin layer and a second resin layer, the surface on the second resin layer side is the first surface of the resin film, and the surface on the first resin layer side is the first surface of the resin film. There are two sides. In the case of a resin film having a three-layer structure including the first resin layer, the second resin layer and the third resin layer, the surface on the second resin layer side is the first surface of the resin film, and the surface on the third resin layer side is the resin. It is the second side of the film. Examples of the method for forming the metal layer include a method such as thin film deposition.

For example, two metallized films having a metal layer formed on the first surface of a resin film are stacked in a state of being displaced by a predetermined distance in the width direction, and then wound to obtain a laminated body. If necessary, the laminate may be sandwiched from a direction perpendicular to the width direction and pressed into an elliptical cylinder shape.

Subsequently, by forming an external terminal electrode on the end face of the laminated body, a film capacitor as shown in FIG. 1 can be obtained. As a method of forming an external terminal electrode on the end face of the laminated body, thermal spraying can be mentioned.

Hereinafter, examples in which the film for a film capacitor of the present invention is disclosed more specifically will be shown. The present invention is not limited to these examples.

[Preparation of resin film]
(Samples 1 to 6)
A phenoxy resin having a plurality of hydroxyl groups was prepared as the first organic material, and diphenylmethane diisocyanate (MDI) was prepared as the second organic material. As the phenoxy resin, a phenoxy resin which is a high molecular weight bisphenol A type epoxy resin having an epoxy group at the terminal was used. Moreover, as the said MDI, a polypeptide MDI was used.

The first organic material and the second organic material were mixed and dissolved in a mixed solvent of methyl ethyl ketone (MEK) and tetrahydrofuran (THF) to prepare a first resin solution.

The obtained first resin solution was molded on a PET film with a doctor blade coater to form a first resin layer having a thickness of 3 μm.

Separately, a second resin solution containing a phenoxy resin as a first organic material and silica particles having an average particle diameter of 80 nm as first particles was prepared. In Samples 1 to 6, the ratio of the silica particles to the resin was changed to prepare a second resin solution.

A second resin solution was applied to the first resin layer on the PET film using a doctor blade coater to form a second resin layer having a thickness of 50 nm.

After the two-layer film produced above was heat-treated and cured, the resin film was peeled off from the PET film. Based on the above, Samples 1 to 6 were prepared.

(Sample 7)
When preparing the second resin solution, a resin film was obtained by the same method as in Samples 1 to 6, except that polyvinyl acetal acetal (PVAA) resin was used instead of the phenoxy resin as the first organic material. As described above, the sample 7 was prepared.

(Sample 8)
When preparing the second resin solution, the resin film was prepared by the same method as in Samples 1 to 6, except that phenoxy resin was used as the first organic material and MDI was used as the second organic material. Obtained. As described above, the sample 8 was prepared.

(Sample 9)
When preparing the first resin solution, Samples 1 to 1 except that PVAA resin was used instead of phenoxy resin as the first organic material and tolylene diisocyanate (TDI) was used instead of MDI as the second organic material. A resin film was obtained by the same method as in 6. As described above, the sample 9 was prepared.

(Sample 10)
When preparing the first resin solution, Samples 1 to 6 were used except that polyvinyl butyral (PVB) resin was used instead of phenoxy resin as the first organic material and TDI was used instead of MDI as the second organic material. A resin film was obtained by the same method as in the above. As described above, the sample 10 was prepared.

(Sample 11)
When preparing the first resin solution, the second organic material is not used, PVB resin is used instead of the phenoxy resin as the first organic material, and when preparing the second resin solution, the phenoxy resin is used as the first organic material. A resin film was obtained by the same method as in Samples 1 to 6, except that PVAA resin was used instead of PVAA resin. As described above, the sample 11 was prepared.

[Particle diameter D1]
For the samples 1 to 11, the particle diameter D1 of the silica particles was determined from the SEM image of the surface of the second resin layer by the above method. D1 of each sample is shown in Table 1.

[Distance between particles L1 and standard deviation σ1 of distance between particles]
For the samples 1 to 11, the interparticle distance L1 and the standard deviation σ1 of the interparticle distance of the silica particles existing on the surface of the second resin layer were obtained from the SEM image of the surface of the second resin layer by the above method. Table 1 shows L1 and σ1 of each sample.

Further, for the samples 1 to 11, Table 1 shows the ratio L1 / D1 of the interparticle distance L1 to the particle diameter D1 and the ratio σ1 / D1 of the standard deviation σ1 of the interparticle distance to the particle diameter D1.

[Evaluation of slipperiness]
For the samples 1 to 11, the frictional force when the two resin films were laminated was measured by the following method, and the static friction coefficient and the dynamic friction coefficient of the resin films were calculated.
When the surface on the second resin layer side is the first surface of the resin film and the surface on the first resin layer side is the second surface of the resin film, first, the first resin film is placed on top of the second resin layer. And fix it to a square plate. On the other hand, a square weight (weight 200 g) is arranged on the second resin layer of the second resin film and attached to the second resin film. The weight to which the second resin film is attached is brought into contact with the first resin film fixed to the square plate. As a result, the first surface of the first resin film and the second surface of the second resin film come into contact with each other. The square weight to which the second resin film is attached is attached to a force gauge manufactured by Imada and is moved horizontally at a speed of 150 mm / min. Here, the maximum frictional force until the weight starts to move is read, and the static friction coefficient is calculated from this value. Further, the dynamic friction coefficient is calculated from the average value of the frictional force whose displacement is between 10 mm and 40 mm.

In this embodiment, when both the static friction coefficient and the dynamic friction coefficient of the resin film are 0.5 or less, it is determined that the slipperiness of the resin film is good. Table 1 shows the static friction coefficient and the dynamic friction coefficient of each sample.

[Evaluation of withstand voltage strength]
An evaluation sample in which aluminum-deposited electrodes (the electrode area of the overlapping portion was 30 cm ² ) was formed on both sides of each of the resin films of Samples 1 to 11 was prepared. A voltage was applied to the prepared evaluation sample at 100 V / μm for 10 minutes, and then the voltage was increased at 25 V / μm intervals. Each voltage was held for 10 minutes, and the electric field strength when a fracture mark was formed on the film was recorded. The measurement was continued until the destruction was seen at 16 points in total. A Weibull plot was created based on the recorded results, and the value at which the failure rate was 50% was defined as the dielectric breakdown strength. The temperature around the film during measurement was 125 ° C.

In this embodiment, when the dielectric breakdown strength exceeds 300 V / μm, it is determined that the withstand voltage strength is high. Table 1 shows the dielectric breakdown strength of each sample.

In Table 1, the sample numbers marked with * are comparative examples outside the scope of the present invention.

Among the samples 1 to 6 in which the resin material of the second resin layer is phenoxy resin, the value of the ratio L1 / D1 of the interparticle distance L1 to the particle size D1 is 3.5 or more and 15 or less, and the interparticles with respect to the particle size D1. In the samples 3 to 5 in which the value of the ratio σ1 / D1 of the standard deviation σ1 of the distance is 1.0 or more and 8.0 or less, both the static friction coefficient and the dynamic friction coefficient are 0.5 or less, and the slipperiness is very good. Has been obtained. On the other hand, the sample 1 in which the value of the ratio L1 / D1 of the interparticle distance L1 to the particle diameter D1 exceeds 15, and the value of the ratio σ1 / D1 of the standard deviation σ1 of the interparticle distance to the particle diameter D1 exceeds 8.0. In 1 and 2, both the static friction coefficient and the dynamic friction coefficient exceed 0.5, and the slipperiness is deteriorated. Further, the value of the ratio L1 / D1 of the interparticle distance L1 to the particle diameter D1 is less than 3.5, and the value of the ratio σ1 / D1 of the standard deviation σ1 of the interparticle distance to the particle diameter D1 is less than 1.0. In the sample 6, the dielectric breakdown strength is 300 V / μm or less, and the result that the sample 6 is not suitable for use as a film for a film capacitor is obtained.

Further, the sample 7 in which the resin material of the second resin layer was changed to PVAA resin, the sample 8 in which the resin material of the second resin layer was changed to a mixed material of phenoxy resin and MDI, and the resin material of the first resin layer was PVAA resin. In sample 9 changed to a mixed material of TDI and TDI, sample 10 changed to a mixed material of PVB resin and TDI for the resin material of the first resin layer, and sample 11 changed to PVB resin for the resin material of the first resin layer. Also, the value of the ratio L1 / D1 of the interparticle distance L1 to the particle diameter D1 is 3.5 or more and 15 or less, or the value of the ratio σ1 / D1 of the standard deviation σ1 of the interparticle distance to the particle diameter D1 is 1.0. If it is 8.0 or less, very good slipperiness and insulation fracture strength are obtained.

1, 2 Film for film condenser 11 1st surface 12 2nd surface 20 Resin film 21 1st resin layer 22 2nd resin layer 23 3rd resin layer 31 1st particle 32 2nd particle 100 Film capacitor 110 1st dielectric Film 120 First metal layer 130 First metallized film 140 Second dielectric film 150 Second metal layer 160 Second metallized film 170 First external terminal electrode 180 Second external terminal electrode D1 First Particle diameter of 1 particle L1 Distance between particles of the 1st particle

Claims (12)

Dielectric film and
A metal layer provided on at least one surface of the dielectric film and
Equipped with
The dielectric film is composed of a resin film having a first surface and a second surface facing each other in the thickness direction.
The resin film includes a first resin layer and a second resin layer whose one surface constitutes the first surface of the resin film.
The second resin layer contains a plurality of first particles and contains a plurality of first particles.
When the particle diameter of the first particles existing on the first surface of the resin film is D1, the interparticle distance is L1, and the standard deviation of the interparticle distance is σ1.
The ratio L1 / D1 of the interparticle distance L1 to the particle diameter D1 is 3.5 or more and 15 or less.
A film capacitor in which the ratio σ1 / D1 of the standard deviation σ1 of the distance between particles to the particle diameter D1 is 1.0 or more and 8.0 or less. The resin film further includes a third resin layer having one surface constituting the second surface of the resin film.
The third resin layer contains a plurality of second particles and contains a plurality of second particles.
When the particle diameter of the second particles existing on the second surface of the resin film is D2, the interparticle distance is L2, and the standard deviation of the interparticle distance is σ2.
The ratio L2 / D2 of the interparticle distance L2 to the particle diameter D2 is 3.5 or more and 15 or less.
The film capacitor according to claim 1, wherein the ratio σ2 / D2 of the standard deviation σ2 of the interparticle distance to the particle diameter D2 is 1.0 or more and 8.0 or less. Dielectric film and
A metal layer provided on at least one surface of the dielectric film and
Equipped with
The dielectric film is composed of a resin film having a first surface and a second surface facing each other in the thickness direction.
The resin film includes a first resin layer and a second resin layer whose one surface constitutes the first surface of the resin film.
The second resin layer contains a plurality of first particles and contains a plurality of first particles.
When the particle diameter of the first particles existing on the first surface of the resin film is D1 and the distance between particles is L1.
A film capacitor in which the ratio L1 / D1 of the interparticle distance L1 to the particle diameter D1 is 3.5 or more and 15 or less. The resin film further includes a third resin layer having one surface constituting the second surface of the resin film.
The third resin layer contains a plurality of second particles and contains a plurality of second particles.
When the particle diameter of the second particles existing on the second surface of the resin film is D2 and the distance between particles is L2,
The film capacitor according to claim 3, wherein the ratio L2 / D2 of the interparticle distance L2 to the particle diameter D2 is 3.5 or more and 15 or less. Dielectric film and
A metal layer provided on at least one surface of the dielectric film and
Equipped with
The dielectric film is composed of a resin film having a first surface and a second surface facing each other in the thickness direction.
The resin film includes a first resin layer and a second resin layer whose one surface constitutes the first surface of the resin film.
The second resin layer contains a plurality of first particles and contains a plurality of first particles.
When the particle diameter of the first particles existing on the first surface of the resin film is D1 and the standard deviation of the interparticle distance is σ1.
A film capacitor in which the ratio σ1 / D1 of the standard deviation σ1 of the distance between particles to the particle diameter D1 is 1.0 or more and 8.0 or less. The resin film further includes a third resin layer having one surface constituting the second surface of the resin film.
The third resin layer contains a plurality of second particles and contains a plurality of second particles.
When the particle diameter of the second particles existing on the second surface of the resin film is D2 and the standard deviation of the interparticle distance is σ2,
The film capacitor according to claim 5, wherein the ratio σ2 / D2 of the standard deviation σ2 of the interparticle distance to the particle diameter D2 is 1.0 or more and 8.0 or less. A film for a film capacitor, which is composed of a resin film having a first surface and a second surface facing each other in the thickness direction.
The resin film includes a first resin layer and a second resin layer whose one surface constitutes the first surface of the resin film.
The second resin layer contains a plurality of first particles and contains a plurality of first particles.
When the particle diameter of the first particles existing on the first surface of the resin film is D1, the interparticle distance is L1, and the standard deviation of the interparticle distance is σ1.
The ratio L1 / D1 of the interparticle distance L1 to the particle diameter D1 is 3.5 or more and 15 or less.
A resin film having a ratio σ1 / D1 of the standard deviation σ1 of the distance between particles to the particle diameter D1 of 1.0 or more and 8.0 or less. The resin film further includes a third resin layer having one surface constituting the second surface of the resin film.
The third resin layer contains a plurality of second particles and contains a plurality of second particles.
When the particle diameter of the second particles existing on the second surface of the resin film is D2, the interparticle distance is L2, and the standard deviation of the interparticle distance is σ2.
The ratio L2 / D2 of the interparticle distance L2 to the particle diameter D2 is 3.5 or more and 15 or less.
The resin film according to claim 7, wherein the ratio σ2 / D2 of the standard deviation σ2 of the interparticle distance to the particle diameter D2 is 1.0 or more and 8.0 or less. A film for a film capacitor, which is composed of a resin film having a first surface and a second surface facing each other in the thickness direction.
The resin film includes a first resin layer and a second resin layer whose one surface constitutes the first surface of the resin film.
The second resin layer contains a plurality of first particles and contains a plurality of first particles.
When the particle diameter of the first particles existing on the first surface of the resin film is D1 and the distance between particles is L1.
A resin film having a ratio L1 / D1 of the interparticle distance L1 to the particle diameter D1 of 3.5 or more and 15 or less. The resin film further includes a third resin layer having one surface constituting the second surface of the resin film.
The third resin layer contains a plurality of second particles and contains a plurality of second particles.
When the particle diameter of the second particles existing on the second surface of the resin film is D2 and the distance between particles is L2,
The resin film according to claim 9, wherein the ratio L2 / D2 of the distance L2 between the particles to the particle diameter D2 is 3.5 or more and 15 or less. A film for a film capacitor, which is composed of a resin film having a first surface and a second surface facing each other in the thickness direction.
The resin film includes a first resin layer and a second resin layer whose one surface constitutes the first surface of the resin film.
The second resin layer contains a plurality of first particles and contains a plurality of first particles.
When the particle diameter of the first particles existing on the first surface of the resin film is D1 and the standard deviation of the interparticle distance is σ1.
A resin film having a ratio σ1 / D1 of the standard deviation σ1 of the distance between particles to the particle diameter D1 of 1.0 or more and 8.0 or less. The resin film further includes a third resin layer having one surface constituting the second surface of the resin film.
The third resin layer contains a plurality of second particles and contains a plurality of second particles.
When the particle diameter of the second particles existing on the second surface of the resin film is D2 and the standard deviation of the interparticle distance is σ2,
The resin film according to claim 11, wherein the ratio σ2 / D2 of the standard deviation σ2 of the interparticle distance to the particle diameter D2 is 1.0 or more and 8.0 or less.

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