JP2022045538A - Film capacity and resin film - Google Patents

Abstract

To provide a film capacitor that includes a resin film, of which the coefficient of static friction is low and the slipperiness is 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 1 having a first surface 11 and a second surface 12 in the thickness direction. The resin film 1 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 1. The second resin layer 22 contains a plurality of inorganic particles 31. The content of inorganic particles 31 in the whole of the film, with the dielectric film 110 and the metal layer 120 combined together, is 1.2% by weight to 2.7% by weight, both ends inclusive. Assuming that D1 represents the particle diameter of inorganic particles 31 protruding from the first surface 11 of the resin film 1 and H1 represents a protrusion height from the first surface 11, the ratio H1/D1 of the protrusion height H1 to the particle diameter D1 is 0.2 and over to less than 1.SELECTED DRAWING: Figure 2

Description

The present invention relates to film capacitors and resin films.

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.

As a method for improving the slipperiness of a resin film, Patent Document 1 describes a method for producing a film with particles in which particles are immobilized on the surface of a base film without using a binder, and a method for producing the same. Disclosed are films with particles that can be produced by.

JP-A-2015-172158

Patent Document 1 describes, as a preferred method for adhering particles to the surface of a base film, a method of generating particles in a flame and blowing the flame onto the surface of the base film. However, such a method is not applicable to all resin films.

Further, the method for producing a film with particles described in Patent Document 1 is characterized in that a binder is not used. Therefore, there is a concern that the thickness of the film may vary due to the particles being directly embedded in the film. In this case, for example, when it is used as a dielectric film of a film capacitor, the withstand voltage strength of the film capacitor may decrease.

Further, in the examples of Patent Document 1, the coefficient of static friction of the film exceeds 0.5 in each case. However, in order to use it as a dielectric film of a film capacitor, for example, it is desired to further reduce the coefficient of static friction of the film in order to improve the slipperiness of the film.

An object of the present invention is to provide a film capacitor provided with a resin film having a low static friction coefficient and high slipperiness. Further, it is an object of the present invention to provide a resin film having a low static friction coefficient and high slipperiness.

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 inorganic particles. The content of the inorganic particles in the entire film obtained by combining the dielectric film and the metal layer is 1.2% by weight or more and 2.7% by weight or less. When the particle diameter of the inorganic particles protruding from the first surface of the resin film is D1 and the protrusion height from the first surface is H1, the ratio H1 of the protrusion height H1 to the particle diameter D1 is H1. / D1 is 0.2 or more and less than 1.

The resin film of the present invention has 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 inorganic particles. The content of the inorganic particles in the second resin layer is 30% by weight or more and 70% by weight or less. When the particle diameter of the inorganic particles protruding from the first surface of the resin film is D1 and the protrusion height from the first surface is H1, the ratio H1 of the protrusion height H1 to the particle diameter D1 is H1. / D1 is 0.2 or more and less than 1.

According to the present invention, it is possible to provide a film capacitor including a resin film having a low static friction coefficient and high slipperiness.

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 resin film of the present invention. FIG. 3 is a cross-sectional view schematically showing another example of the resin film of the present invention. FIG. 4 is a cross-sectional view schematically showing still another example of the resin film of the present invention. FIG. 5 is a cross-sectional view schematically showing the structures of Samples 1, 2, 5, 6, 10 and 12-19. FIG. 6 is a cross-sectional view schematically showing the structures of the samples 3 and 8. FIG. 7 is a cross-sectional view schematically showing the structure of the sample 9. FIG. 8 is a cross-sectional view schematically showing the structures of the samples 4, 7 and 11.

Hereinafter, the film capacitor and the resin film of the present invention 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 ends of 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 each of the first metallized film 130 and the second metallized film 160 is provided. 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 resin film 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 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 resin film of the present invention may be used for both the first dielectric film 110 and the second dielectric film 140, or the present invention may be used for only one of them. Resin film may be used. In the film capacitor of the present invention, when the resin film of the present invention is used for both the first dielectric film and the second dielectric film, the resin films of the same embodiment may be used for both, or they may be used separately. The resin film of the above aspect may be used.

[Resin film]
FIG. 2 is a cross-sectional view schematically showing an example of the resin film 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 inorganic particles 31 shown in FIG. 2 have been appropriately changed for the sake of clarity and simplification of the drawings. .. The same applies to other drawings.

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

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. ..

The second resin layer 22 contains a plurality of inorganic particles 31. The inorganic particles 31 project from the first surface 11 of the resin film 1. That is, the inorganic particles 31 project from the surface of the second resin layer 22. In the example shown in FIG. 2, all the inorganic particles 31 project from the first surface 11 of the resin film 1. Inorganic particles 31 that do not protrude from the first surface 11 of the resin film 1 and are buried in the second resin layer 22 may be contained. Further, the inorganic particles 31 may or may not be in contact with the first resin layer 21. The sizes of the inorganic particles 31 may be the same or different.

The content of the inorganic particles 31 in the second resin layer 22 is 30% by weight or more and 70% by weight or less. When the content of the inorganic particles 31 in the second resin layer 22 is less than 30% by weight, the surface of the resin film 1 is less likely to be roughened, so that the slipperiness of the resin film 1 is less likely to be improved. On the other hand, when the content of the inorganic particles 31 in the second resin layer 22 exceeds 70% by weight, the proportion of the resin component in the second resin layer 21 decreases, so that the inorganic particles 31 are removed from the surface of the resin film 1. It becomes easy to separate, and the slipperiness of the resin film 1 may decrease.

The content of the inorganic particles 31 in the second resin layer 22 is measured by the following method.
First, the weight of the second resin layer 22 is obtained from the film thickness of the first resin layer 21 and the film thickness and the specific gravity of the second resin layer 22. Then, the whole film is heated at 500 ° C. to decompose all the organic components contained in the film, and the weight of the remaining inorganic components is measured. The content of the inorganic particles 31 in the second resin layer 22 is obtained from the weight of the inorganic component and the weight of the second resin layer 22.

On the other hand, when the resin film 1 is used as a dielectric film of a film capacitor, a metal layer is vapor-deposited on the surface of the resin film 1. In that case, the content of the inorganic particles 31 in the entire film in which the resin film 1 as the dielectric film and the metal layer are combined is preferably 1.2% by weight or more and 2.7% by weight or less. When the content of the inorganic particles 31 in the entire film with the metal layer is less than 1.2% by weight, the surface of the resin film 1 is less likely to be roughened, so that the slipperiness of the resin film 1 is less likely to be improved. On the other hand, when the content of the inorganic particles 31 in the entire film with the metal layer exceeds 2.7% by weight, the proportion of the resin component decreases, so that the inorganic particles 31 are easily detached from the surface of the resin film 1. The slipperiness of the resin film 1 may decrease.

The content of the inorganic particles 31 when the metal layer is vapor-deposited on the surface of the resin film 1 is calculated in consideration of the weight of the metal. That is, the content of the inorganic particles 31 in the entire film is calculated from the weight obtained by subtracting the metal weight from the weight of the inorganic component after heating and the weight of the entire film containing the metal before heating. The weight of the metal after heating can be obtained from the film thickness and the metal density of the metal layer deposited on the film before heating.

When the particle diameter of the inorganic particles 31 protruding from the first surface 11 of the resin film 1 is D1 (see FIG. 2) and the protruding height from the first surface 11 is H1 (see FIG. 2), the particle diameter D1 The ratio H1 / D1 of the protrusion height H1 to the above is 0.2 or more and less than 1, preferably 0.2 or more and 0.75 or less.

The content of the inorganic particles 31 in the second resin layer 22 is 30% by weight or more and 70% by weight or less, and the protrusion height of the inorganic particles 31 protruding from the first surface 11 of the resin film 1 with respect to the particle diameter D1. By setting the ratio H1 / D1 of H1 to 0.2 or more, the static friction coefficient of the resin film 1 is reduced, so that the slipperiness of the resin film 1 is improved. On the other hand, when the inorganic particles 31 are desorbed from the surface of the resin film 1, the slipperiness of the resin film 1 decreases, so that the ratio H1 / D1 of the protrusion height H1 to the particle diameter D1 needs to be less than 1, which is preferable. It shall be 0.75 or less.

The ratio H1 / D1 of the protruding height H1 to the particle diameter D1 of the inorganic particles 31 protruding from the first surface 11 of the resin film 1 is measured by the following method.
First, an image of a cross section of the resin film 1 is taken using a scanning electron microscope (SEM). Three inorganic particles 31 protruding from the first surface 11 of the resin film 1, that is, the second resin layer 22, are randomly extracted from the photographed cross-sectional image. For each particle, the ratio of the protrusion height to the particle diameter is obtained, and the average value is H1 / D1. The diameter corresponding to the circle of the particles observed from the photographed cross-sectional image is defined as the particle diameter.

As described above, in the resin film 1, the content of the inorganic particles 31 in the second resin layer 22 and the protruding height H1 of the inorganic particles 31 protruding from the first surface 11 of the resin film 1 with respect to the particle diameter D1. By setting both of the ratios H1 / D1 to a specific range, the static friction coefficient of the resin film 1 is reduced, so that the slipperiness of the resin film 1 is improved.

The inorganic particles 31 are preferably silica particles.

The average particle size of the inorganic particles 31 in the second resin layer 22 is not particularly limited, but is preferably 10 nm or more and 200 nm or less.

The average particle size of the inorganic particles 31 is measured by the following method.
First, an image of a cross section of the resin film 1 is taken using SEM. Three inorganic particles 31 are randomly extracted from the photographed cross-sectional image. The particle size of each particle is obtained, and the average value is taken as the average particle size. Similar to the above, the diameter corresponding to the circle of the particles observed from the photographed cross-sectional image is defined as the particle diameter.

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 of the first resin layer 21 is not particularly limited.
The thickness of the first resin layer 21 can be measured using an optical film thickness meter. Similarly, the thickness of the second resin layer 22 or 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 inorganic 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 of the second resin layer 22 is not particularly limited, but is preferably 5 nm or more and 200 nm or less. The thickness of the second resin layer 22 referred to here means the thickness measured at a position where the inorganic particles 31 do not protrude from the surface.

FIG. 3 is a cross-sectional view schematically showing another example of the resin film of the present invention.
As in the resin film 2 shown in FIG. 3, a part of the inorganic particles 31 may be buried in the resin layer (first resin layer 21 in FIG. 3) adjacent to the second resin layer 22. Inorganic particles 31 that are not buried in the resin layer adjacent to the second resin layer 22 may be contained.

FIG. 4 is a cross-sectional view schematically showing still another example of the resin film of the present invention.
The resin film 3 shown in FIG. 4 further includes a third resin layer 23. In the resin film 3, one surface of the second resin layer 22 constitutes the first surface 11 of the resin film 3, and one surface of the third resin layer 23 constitutes the second surface 12 of the resin film 3.

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 inorganic particles 31. The inorganic particles 31 project from the second surface 12 of the resin film 3. That is, the inorganic particles 31 project from the surface of the third resin layer 23. In the example shown in FIG. 4, all the inorganic particles 31 protrude from the second surface 12 of the resin film 3. Inorganic particles 31 that do not protrude from the second surface 12 of the resin film 3 and are buried in the third resin layer 23 may be contained. Further, the inorganic particles 31 may or may not be in contact with the first resin layer 21. The sizes of the inorganic particles 31 may be the same or different.

The content of the inorganic particles 31 in the third resin layer 23 is preferably 30% by weight or more and 70% by weight or less. The content of the inorganic particles 31 in the third resin layer 23 is measured by the same method as the content of the inorganic particles 31 in the second resin layer 22. The content of the inorganic particles 31 in the third resin layer 23 may be the same as or different from the content of the inorganic particles 31 in the second resin layer 22.

When the particle diameter of the inorganic particles 31 protruding from the second surface 12 of the resin film 3 is D2 (see FIG. 4) and the protrusion height from the second surface 12 is H2 (see FIG. 4), the particle diameter D2. The ratio H2 / D2 of the protrusion height H2 to the above is preferably 0.2 or more and less than 1, and more preferably 0.2 or more and 0.75 or less. The ratio H2 / D2 of the protrusion height H2 to the particle diameter D2 is measured by the same method as the ratio H1 / D1 of the protrusion height H1 to the particle diameter D1. The ratio H2 / D2 of the protrusion height H2 to the particle diameter D2 may be the same as or different from the ratio H1 / D1 of the protrusion height H1 to the particle diameter D1.

In the resin film 3 shown in FIG. 4, the inorganic particles 31 are formed on the resin layer (for example, the first resin layer 21) adjacent to the third resin layer 23 like the second resin layer 22 constituting the resin film 2 shown in FIG. A part of the plastic may be buried. Inorganic particles 31 that are not buried in the resin layer adjacent to the third resin layer 23 may be contained.

The material constituting the inorganic particles 31 in the third resin layer 23 may be different from the material constituting the inorganic particles 31 in the second resin layer 22, but is preferably the same.

The average particle size of the inorganic particles 31 in the third resin layer 23 is not particularly limited, but is preferably 10 nm or more and 200 nm or less. The average particle size of the inorganic particles 31 in the third resin layer 23 may be the same as or different from the average particle size of the inorganic particles 31 in the second resin layer 22.

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

The thickness of the third resin layer 23 is not particularly limited, but is preferably 5 nm or more and 200 nm or less. The thickness of the third resin layer 23 referred to here means the thickness measured at a position where the inorganic particles 31 do not protrude from the surface. The thickness of the third resin layer 23 may be the same as or different from the thickness of the second resin layer 22.

[Manufacturing method of resin film]
Hereinafter, an example of the method for producing the resin film 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 inorganic particles in a solvent, mixing them, and adding additives as necessary. A second organic material may be mixed with the second resin solution. When the ratio of the weight of the inorganic particles to the total weight of the first organic material, the second organic material and the inorganic particles in the second resin solution is defined as "the content of the inorganic particles in the second resin solution", the second resin The content of the inorganic particles in the solution is preferably 30% by weight or more and 70% by weight or less. 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 inorganic particles in a solvent, mixing them, and adding additives as necessary. The second organic material may be mixed with the third resin solution. When the ratio of the weight of the inorganic particles to the total weight of the first organic material, the second organic material and the inorganic particles in the third resin solution is defined as "the content of the inorganic particles in the third resin solution", the third resin The content of the inorganic particles in the solution is preferably 30% by weight or more and 70% by weight or less. 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. From the above, a resin film 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 resin film 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 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.

The application of the resin film of the present invention is not limited to the dielectric film of the film capacitor, and can be used for any application in which the slipperiness of the film surface is required.

Hereinafter, examples in which the resin film 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 13)
A phenoxy resin was prepared as the first organic material, and diphenylmethane diisocyanate (MDI) was prepared as the second organic material. The first organic material and the second organic material were mixed at a weight ratio of 70/30 and diluted with a mixed solution of methyl ethyl ketone (MEK) and tetrahydrofuran (THF) to prepare a first resin solution.

Using a gravure coater, a first resin solution was applied onto a PET film which is a base film to form a first resin layer having a thickness of about 3.0 μm.

Separately, a phenoxy resin was prepared as the first organic material, and silica particles having an average particle diameter of 80 nm were prepared as the inorganic particles. A mixture of the first organic material and silica particles was diluted with a mixture of MEK and THF to prepare a second resin solution.

Here, the content of the silica particles in the second resin solution was set to 10% by weight to 75% by weight as shown in Table 1. The content of the silica particles is expressed as a percentage by dividing the weight of the silica particles contained in the second resin solution by the total weight of the first organic material and the silica particles.

A second resin solution was applied to the first resin layer on the PET film using a gravure coater. At this time, by setting the solid content concentration in the second resin solution to 0.5% by weight to 7.5% by weight as shown in Table 1, a second resin layer having a thickness of 50 nm to 200 nm was formed. .. The solid content concentration is expressed as a percentage by dividing the total weight of the first organic material and the silica particles by the weight of the entire second resin solution.

The two-layer film produced above was peeled off from the PET film and heat-treated at 150 ° C. for 4 hours to cure to obtain a resin film. Based on the above, samples 1 to 13 were prepared.

(Sample 14)
A resin film was obtained by the same method as in Sample 6 except that polyvinyl acetal acetal (PVAA) resin was used instead of phenoxy resin as the first organic material when preparing the second resin solution. As described above, the sample 14 was prepared.

(Sample 15)
A resin film was obtained by the same method as in Sample 1 except that PVAA resin was used instead of phenoxy resin as the first organic material when preparing the second resin solution. As described above, the sample 15 was prepared.

(Sample 16)
When preparing the second resin solution, a resin film was obtained by the same method as in Sample 6, except that phenoxy resin was used as the first organic material and MDI was used as the second organic material. .. The content of the silica particles is expressed as a percentage by dividing the weight of the silica particles contained in the second resin solution by the total weight of the first organic material, the second organic material and the silica particles. .. The solid content concentration is expressed as a percentage by dividing the total weight of the first organic material, the second organic material, and the silica particles by the weight of the entire second resin solution. As described above, the sample 16 was prepared.

(Sample 17)
When preparing the first resin solution, 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, the sample 6 and the sample 6 A resin film was obtained by the same method. As described above, the sample 17 was prepared.

(Sample 18)
Similar to Sample 6 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 when preparing the first resin solution. A resin film was obtained by the above method. As described above, the sample 18 was prepared.

(Sample 19)
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 Sample 6, except that PVAA resin was used instead of PVAA resin. As described above, the sample 19 was prepared.

FIG. 5 is a cross-sectional view schematically showing the structures of Samples 1, 2, 5, 6, 10 and 12-19. FIG. 6 is a cross-sectional view schematically showing the structures of the samples 3 and 8. FIG. 7 is a cross-sectional view schematically showing the structure of the sample 9. FIG. 8 is a cross-sectional view schematically showing the structures of the samples 4, 7 and 11.

The silica particles, which are the inorganic particles 31, may not be completely buried in the second resin layer 22, as in Samples 1, 2, 5, 6, 10 and 12-19, and Samples 3, 4 , 7, 8, 9 and 11, some silica particles may be buried in the second resin layer 22. Further, the silica particles in the second resin layer 22 may or may not be partially buried in the first resin layer 21.

[Content rate of silica particles in the second resin layer]
For the resin films of Samples 1 to 19, the content of silica particles in the second resin layer was measured by the above-mentioned method. Table 1 shows the content of silica particles in the second resin layer of each sample.

[Ratio of protrusion height H1 to particle diameter D1 H1 / D1]
For the resin films of Samples 1 to 19, the value of the ratio H1 / D1 of the protrusion height H1 to the particle diameter D1 was calculated from the SEM image of the cross section by the above-mentioned method. The values of H1 / D1 of each sample are shown in Table 1.

[Content of silica particles in the entire film with metal layer]
Aluminum-deposited electrodes having a film thickness of 10 nm were formed as a metal layer on the resin films of Samples 1 to 19. The content of silica particles in the entire film with a metal layer was measured by the method described above. Table 1 shows the content of silica particles in the entire film with a metal layer of each sample.

[Evaluation of slipperiness]
For the resin films of Samples 1 to 19, the frictional force when two resin films were laminated was measured by the following method, and the coefficient of static friction of the resin films was 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 the second surface. Fix it to a square plate so that it becomes. On the other hand, the second surface of the second resin film is attached to the square weight (weight 200 g) so that the first surface of the second resin film faces outward. The first surface of the second resin film is brought into contact with the second surface of the first resin film fixed to the square plate. Further, the square weight to which the second resin film is attached is attached to a force gauge manufactured by Imada and can be 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.

In this embodiment, when the coefficient of static friction of the resin film is 0.5 or less, it is determined that the slipperiness of the resin film is good. The coefficient of static friction of each sample is shown in Table 1.

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

Among the samples 1 to 13 in which the second resin layer is made of a thermoplastic resin phenoxy resin, the content of silica particles in the entire film is 1.2% by weight or more and 2.7% by weight or less, and the particle size is D1. Samples 3, 5, 6, 8 to 10 and 12 in which the value of the ratio H1 / D1 of the protrusion height H1 is 0.2 or more and less than 1 have a static friction coefficient of 0.5 or less and a resin having good slipperiness. The film is obtained.

In Samples 1 and 2 in which the content of silica particles in the entire film is less than 1.2% by weight, the static friction coefficient is high even if the ratio H1 / D1 of the protrusion height H1 to the particle diameter D1 is 0.2 or more. It exceeds 0.5 and is a resin film with poor slipperiness. Even in the sample 13 in which the content of silica particles in the entire film exceeds 2.7% by weight, the coefficient of static friction exceeds 0.5, and the resin film has poor slipperiness.

Even if the content of silica particles in the entire film is 1.2% by weight or more and 2.7% by weight or less, in the samples 4, 7 and 11 in which the thickness of the second resin layer is 200 nm, the second resin layer is used. Since the amount of the resin contained therein increases, the silica particles in the second resin layer are likely to be buried. As a result, when the value of the ratio H1 / D1 of the protrusion height H1 to the particle diameter D1 is less than 0.2, the static friction coefficient exceeds 0.5 in each case, so that the resin film has poor slipperiness.

Even in the sample 14 in which the resin material of the second resin layer is changed to PVAA resin, the content of silica particles in the entire film is 1.2% by weight or more and 2.7% by weight or less, and the protrusion height with respect to the particle size D1. When the value of the ratio H1 / D1 of H1 is 0.2 or more and less than 1, a resin film having good slipperiness is obtained. On the other hand, the sample 15 in which the content of silica particles in the entire film is less than 1.2% by weight is a resin film having a static friction coefficient of more than 0.5 and having poor slipperiness.

Even in the sample 16 in which MDI is added to the film composition of the second resin layer to form a resin film made of a thermosetting resin, the same slipperiness as when the second resin layer is made of a phenoxy resin which is a thermoplastic resin can be obtained. Has been done.

In the sample 17 using PVAA resin / TDI which is another thermosetting resin and the sample 18 using PVB resin / TDI as the film composition of the first resin layer, the phenoxy resin / MDI was also used in the first resin layer. The same slipperiness as the case of using is obtained.

The sample 19 in which the PVB resin, which is a thermoplastic resin, is used for the first resin layer is also a resin film having good slipperiness.

1, 2, 3 Resin film 11 1st surface 12 2nd surface 21 1st resin layer 22 2nd resin layer 23 3rd resin layer 31 Inorganic particles 100 Film capacitor 110 1st dielectric film 120 1st 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, D2 Particle size of inorganic particles H1, Height of protrusion of H2 inorganic particles from the first surface

Claims (8)

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 inorganic particles and contains a plurality of inorganic particles.
The content of the inorganic particles in the entire film including the dielectric film and the metal layer is 1.2% by weight or more and 2.7% by weight or less.
When the particle diameter of the inorganic particles projecting from the first surface of the resin film is D1 and the projecting height from the first surface is H1.
A film capacitor in which the ratio H1 / D1 of the protrusion height H1 to the particle diameter D1 is 0.2 or more and less than 1. The film capacitor according to claim 1, wherein the ratio H1 / D1 of the protrusion height H1 to the particle diameter D1 is 0.2 or more and 0.75 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 the plurality of the inorganic particles and contains the plurality of the inorganic particles.
When the particle diameter of the inorganic particles protruding from the second surface of the resin film is D2 and the protrusion height from the second surface is H2,
The film capacitor according to claim 1 or 2, wherein the ratio H2 / D2 of the protrusion height H2 to the particle diameter D2 is 0.2 or more and less than 1. The film capacitor according to claim 3, wherein the ratio H2 / D2 of the protrusion height H2 to the particle diameter D2 is 0.2 or more and 0.75 or less. 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 inorganic particles and contains a plurality of inorganic particles.
The content of the inorganic particles in the second resin layer is 30% by weight or more and 70% by weight or less.
When the particle diameter of the inorganic particles projecting from the first surface of the resin film is D1 and the projecting height from the first surface is H1.
A resin film in which the ratio H1 / D1 of the protrusion height H1 to the particle diameter D1 is 0.2 or more and less than 1. The resin film according to claim 5, wherein the ratio H1 / D1 of the protrusion height H1 to the particle diameter D1 is 0.2 or more and 0.75 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 the plurality of the inorganic particles and contains the plurality of the inorganic particles.
The content of the inorganic particles in the third resin layer is 30% by weight or more and 70% by weight or less.
When the particle diameter of the inorganic particles protruding from the second surface of the resin film is D2 and the protrusion height from the second surface is H2,
The resin film according to claim 5 or 6, wherein the ratio H2 / D2 of the protrusion height H2 to the particle diameter D2 is 0.2 or more and less than 1. The resin film according to claim 7, wherein the ratio H2 / D2 of the protrusion height H2 to the particle diameter D2 is 0.2 or more and 0.75 or less.

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