Film capacitor, film, and metallized film

Abstract

The thin film capacitor (10) includes a wound body (40) formed by winding a dielectric film (110) and a metal layer (220). The dielectric film (110) contains a cured product of a first organic material having a hydroxyl group and a second organic material having an isocyanate group among aromatic compounds, and has a first main surface (110a) and a second main surface (110b) facing each other in the thickness direction. The metal layer (220) is provided on at least the first main surface (110a) of the dielectric film (110). A plurality of protrusions (120) having the second organic material are present on the first main surface (110a) of the dielectric film (110). In an area of 100 μm × 140 μm on the first main surface (110a) of the dielectric film (110), when defining the film surface at the average height in the thickness direction, the area ratio of the region in the range of 0.05 μm or more and less than 0.20 μm higher than the film surface is 6.04% or less, the area ratio of the region in the range of 0.20 μm or more and less than 2.50 μm higher than the film surface is 0.0998% or more and 1.13% or less, and the area ratio of the region in the range of 2.50 μm or more higher than the film surface is 0.100% or less.

Description

Technical Field

[0001] The present invention relates to thin film capacitors, thin films, and metallized thin films. Background Art

[0002] As one type of capacitor, a thin film capacitor having the following structure is known, that is, while using a flexible thin film as a dielectric film, a first metal layer and a second metal layer that are opposed to each other with the thin film interposed therebetween are arranged. Such a thin film capacitor is manufactured, for example, by winding or laminating a thin film forming the first metal layer and a thin film forming the second metal layer.

[0003] When manufacturing a thin film capacitor by making a wound body by winding a thin film, the wound body may be pressed in order to reduce the height of the thin film capacitor. At this time, if the slidability of the thin film is good, the wound body becomes easy to be uniformly pressed, and thus the height reduction of the thin film capacitor becomes easy.

[0004] On the other hand, in the wound body, if a gap is formed between the mutually overlapping thin films, at the time of insulation breakdown, the decomposition gas from the thin film becomes easy to scatter from the inside of the thin film capacitor, and as a result, the insulation state of the thin film is restored, that is, a so-called self-healing function is made to work. When making the wound body, if the slidability of the thin film is good, a gap is easily and uniformly formed between the mutually overlapping thin films, and thus the self-healing function becomes easy to work.

[0005] Based on the above, in order to improve the pressability and self-healing property of the thin film capacitor, slidability is sometimes imparted to the thin film. As a method of imparting slidability to the thin film, a method of blending an organic filler in a base resin is disclosed in Patent Document 1. Conventionally, slidability is imparted to the thin film by making the surface of the thin film rough by blending a filler in the resin.

[0006] Prior Art Documents

[0007] Patent Documents

[0008] Patent Document 1: Japanese Patent Application Laid-Open No. 2011-251493 Summary of the Invention

[0009] Problems to be Solved by the Invention

[0010] However, in the conventional thin film in which a filler is blended in the resin, since the dielectric constants of the resin and the filler are different, the electric field is likely to concentrate near the filler, and as a result, the insulation breakdown voltage decreases. Therefore, it can be said that there is room for improvement in the conventional thin film in terms of achieving both slidability and withstand voltage.

[0011] On the other hand, by roughening the surface of the thin film, when a thin film capacitor is manufactured by winding the thin film, it becomes easier to form gaps between the mutually overlapping thin films. Therefore, it can be considered that the self-healing function becomes easier to function at the time of dielectric breakdown.

[0012] However, if the hardness of the roughened portion of the thin film surface is low, when the thin film is wound to manufacture a thin film capacitor, the roughened portion of the thin film surface is easily crushed, so it becomes difficult to form gaps between the mutually overlapping thin films. As a result, at the time of dielectric breakdown, the decomposition gas from the thin film becomes difficult to scatter from the inside of the thin film capacitor, so the self-healing function becomes difficult to function.

[0013] The present invention has been completed to solve the above problems, and an object thereof is to provide a thin film capacitor having a dielectric film with excellent slidability and withstand voltage and capable of imparting excellent pressability and self-healing properties. In addition, an object of the present invention is to provide a thin film that can be used as the dielectric film of the above thin film capacitor. Further, an object of the present invention is to provide a metallized thin film that can be used in the above thin film capacitor.

[0014] Technical means for solving the problems

[0015] In a first aspect, the thin film capacitor of the present invention is characterized by comprising a wound body obtained by winding a dielectric film and a metal layer, the dielectric film containing a cured product of a first organic material having a hydroxyl group and a second organic material having an isocyanate group among aromatic compounds, and having a first main surface and a second main surface opposed to each other in the thickness direction, the metal layer being provided on at least the first main surface of the dielectric film, there being a plurality of protrusions having the second organic material on the first main surface of the dielectric film, and in an area of 100 μm × 140 μm on the first main surface of the dielectric film, when defining the film surface at the average height in the thickness direction, the area ratio of the region in the range of more than 0.05 μm and less than 0.20 μm higher than the film surface is 6.04% or less, the area ratio of the region in the range of more than 0.20 μm and less than 2.50 μm higher than the film surface is 0.0998% or more and 1.13% or less, and the area ratio of the region in the range of more than 2.50 μm higher than the film surface is 0.100% or less.

[0016] In the second mode, the thin film capacitor of the present invention is characterized in that it includes a wound body formed by winding a dielectric film and a metal layer. The dielectric film contains a cured product of a first organic material having a hydroxyl group and a second organic material having an isocyanate group among aromatic compounds, and has a first main surface and a second main surface facing each other in the thickness direction. The metal layer is provided on at least the first main surface of the dielectric film. There are a plurality of protrusions having the second organic material on the first main surface of the dielectric film. On the surface of the metal layer provided on the first main surface of the dielectric film, which is on the side opposite to the first main surface of the dielectric film, there are a plurality of convex portions along the plurality of protrusions. In the area of 100 μm × 140 μm of the surface of the metal layer, when defining the metal layer surface at the average height in the thickness direction, the area ratio of the region in the range of more than 0.05 μm and less than 0.20 μm higher than the metal layer surface is 6.17% or less, the area ratio of the region in the range of more than 0.20 μm and less than 2.50 μm higher than the metal layer surface is 0.118% or more and 1.24% or less, and the area ratio of the region in the range of more than 2.50 μm higher than the metal layer surface is 0.100% or less.

[0017] The thin film of the present invention is characterized in that it contains a cured product of a first organic material having a hydroxyl group and a second organic material having an isocyanate group among aromatic compounds, and has a first main surface and a second main surface facing each other in the thickness direction. There are a plurality of protrusions having the second organic material on the first main surface. In the area of 100 μm × 140 μm of the first main surface, when defining the thin film surface at the average height in the thickness direction, the area ratio of the region in the range of more than 0.05 μm and less than 0.20 μm higher than the thin film surface is 6.04% or less, the area ratio of the region in the range of more than 0.20 μm and less than 2.50 μm higher than the thin film surface is 0.0998% or more and 1.13% or less, and the area ratio of the region in the range of more than 2.50 μm higher than the thin film surface is 0.100% or less.

[0018] The metallized film of the present invention is characterized by comprising: a film containing a cured product of a first organic material having a hydroxyl group and a second organic material having an isocyanate group among aromatic compounds, and having a first main surface and a second main surface opposed to each other in the thickness direction; and a metal layer provided on at least the first main surface of the film, there being a plurality of protrusions having the second organic material on the first main surface of the film, and there being a plurality of convex portions along the plurality of protrusions on the surface of the metal layer provided on the first main surface of the film and opposite to the first main surface of the film. In the area of 100 μm × 140 μm on the surface of the metal layer, when defining the metal layer surface at the average height in the thickness direction, the area ratio of the region in the range of more than 0.05 μm and less than 0.20 μm higher than the metal layer surface is 6.17% or less, the area ratio of the region in the range of more than 0.20 μm and less than 2.50 μm higher than the metal layer surface is 0.118% or more and 1.24% or less, and the area ratio of the region in the range of more than 2.50 μm higher than the metal layer surface is 0.100% or less.

[0019] Advantages of the Invention

[0020] According to the present invention, it is possible to provide a thin film capacitor having a dielectric film with excellent slidability, withstand voltage, and capable of imparting excellent pressability and self-healing properties. In addition, according to the present invention, it is possible to provide a film that can be used as the dielectric film of the above thin film capacitor. Furthermore, according to the present invention, it is possible to provide a metallized film that can be used in the above thin film capacitor. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 FIG. is a perspective schematic view showing an example of the thin film capacitor of the present invention.

[0022] Figure 2 FIG. shows the corresponding part of the line segment A1 - A2 in Figure 1 FIG. is a cross-sectional schematic view.

[0023] Figure 3 FIG. shows Figure 1 and Figure 2 FIG. is a perspective schematic view showing an example of the wound body in FIG.

[0024] Figure 4 FIG. is a top view showing an example of the metal layer provided with a fuse portion.

[0025] Figure 5 FIG. is a top view showing an example of the film of the present invention.

[0026] Figure 6 FIG. shows the corresponding part of the line segment in Figure 5Schematic cross-sectional view of the corresponding part of the line segment B1 - B2 in

[0027] Figure 7 is a top view schematic diagram showing an example of the metallized film constituting the thin film capacitor of the present invention.

[0028] Figure 8 is shown in Figure 7 Schematic cross-sectional view of the corresponding part of the line segment C1 - C2 in Detailed implementation mode

[0029] Hereinafter, the thin film capacitor of the present invention, the thin film of the present invention, and the metallized film of the present invention will be described. In addition, the present invention is not limited to the following structures, and can be appropriately changed without departing from the gist of the present invention. In addition, a product obtained by combining a plurality of the following described preferred structures is also the present invention.

[0030] In the first mode and the second mode, the thin film capacitor of the present invention includes a wound body formed by winding a dielectric film and a metal layer. The dielectric film contains a cured product of a first organic material having a hydroxyl group and a second organic material having an isocyanate group among aromatic compounds, and has a first main surface and a second main surface facing each other in the thickness direction. The metal layer is provided on at least the first main surface of the dielectric film.

[0031] Without particularly distinguishing between the first mode and the second mode of the thin film capacitor of the present invention, it is simply referred to as "the thin film capacitor of the present invention".

[0032] Hereinafter, as an example of the thin film capacitor of the present invention, a so-called wound type thin film capacitor in which a metallized film having a metal layer provided on at least one main surface of a dielectric film is wound in a stacked state will be described.

[0033] Figure 1 is a three-dimensional schematic diagram showing an example of the thin film capacitor of the present invention. Figure 2 is shown in Figure 1 Schematic cross-sectional view of the corresponding part of the line segment A1 - A2 in Figure 3 is shown in Figure 1 and Figure 2 Schematic three-dimensional view of an example of the wound body in

[0034] In this specification, as Figure 1 , Figure 2 , and Figure 3As shown, the stacking direction and the width direction in the film capacitor are set to the directions determined by T and W, respectively. In addition, in a wound-type film capacitor, it can be said that there are multiple stacking directions, but in this specification, the direction determined by T is set. Here, the stacking direction T and the width direction W are orthogonal to each other.

[0035] As Figure 1 and Figure 2 shown, the film capacitor 10 has a wound body 40, a first external electrode 41 provided on one end face of the wound body 40, and a second external electrode 42 provided on the other end face of the wound body 40. Here, the two end faces of the wound body 40 face each other in the width direction W.

[0036] As Figure 2 and Figure 3 shown, the wound body 40 is a wound body in which a first metallized film 11 and a second metallized film 12 are stacked in the stacking direction T. That is, the film capacitor 10 is a wound-type film capacitor having the wound body 40.

[0037] In the film capacitor 10, from the viewpoint of reducing the height of the film capacitor 10, it is preferable that when observing a cross section of the wound body 40 perpendicular to the reel axis direction, the cross-sectional shape of the wound body 40 is a flat shape. More specifically, it is preferable that the cross-sectional shape of the wound body 40 pressed is a flat shape such as an ellipse or an oblong, and is made into a shape with a smaller thickness than when the cross-sectional shape of the wound body 40 is a perfect circle.

[0038] Regarding whether the cross-sectional shape of the wound body is pressed into a flat shape, for example, it can be confirmed by whether there are pressing marks on the wound body.

[0039] The film capacitor 10 may also have a cylindrical winding shaft. The winding shaft is arranged on the central axis of the wound first metallized film 11 and the second metallized film 12, and becomes the reel when winding the first metallized film 11 and the second metallized film 12.

[0040] The first metallized film 11 has a first dielectric film 13 and a first metal layer 15.

[0041] The first dielectric film 13 has a first main surface 13a and a second main surface 13b that face each other in the thickness direction ( Figure 2 which is the stacking direction T in this case).

[0042] The first metal layer 15 is provided on the first main surface 13a of the first dielectric film 13. More specifically, the first metal layer 15 is provided to reach one side edge of the first dielectric film 13 in the width direction W and does not reach the other side edge of the first dielectric film 13.

[0043] The second metallized film 12 has a second dielectric film 14 and a second metal layer 16.

[0044] The second dielectric film 14 has a first main surface 14a and a second main surface 14b that face each other in the thickness direction ( Figure 2 which is the stacking direction T).

[0045] The second metal layer 16 is provided on the first main surface 14a of the second dielectric film 14. More specifically, the second metal layer 16 is provided so as not to reach one side edge of the second dielectric film 14 in the width direction W and to reach the other side edge of the second dielectric film 14.

[0046] In the wound body 40, the adjacent first metallized film 11 and second metallized film 12 are offset in the width direction W such that one end of the first metal layer 15 that reaches the side edge of the first dielectric film 13 is exposed on one end face of the wound body 40, and one end of the second metal layer 16 that reaches the side edge of the second dielectric film 14 is exposed on the other end face of the wound body 40.

[0047] Since the wound body 40 is wound in a state where the first metallized film 11 and the second metallized film 12 are stacked in the stacking direction T, it can also be said that the wound body is wound in a state where the first metal layer 15, the first dielectric film 13, the second metal layer 16, and the second dielectric film 14 are stacked in this order in the stacking direction T.

[0048] In the wound body 40, the first metallized film 11 and the second metallized film 12 are wound in a state of being stacked in the stacking direction T such that the first metallized film 11 is on the inner side of the second metallized film 12, the first metal layer 15 is on the inner side of the first dielectric film 13, and the second metal layer 16 is on the inner side of the second dielectric film 14. That is, the first metal layer 15 and the second metal layer 16 face each other with the first dielectric film 13 or the second dielectric film 14 interposed therebetween.

[0049] The second metal layer 16 may not be provided on the first main surface 14a of the second dielectric film 14 but may be provided on the second main surface 13b of the first dielectric film 13. In this case, in the wound body 40, a metallized film having the first metal layer 15 provided on the first main surface 13a of the first dielectric film 13 and the second metal layer 16 provided on the second main surface 13b, and the second dielectric film 14 are wound in a state of being stacked in the stacking direction T.

[0050] It is preferable to provide fuse portions on the first metal layer 15 and the second metal layer 16, respectively.

[0051] Figure 4It is a plan view showing an example of a metal layer provided with a fuse portion.

[0052] As Figure 4 shown, in the first metal layer 15, a plurality of divided electrode portions 61, electrode portions 62, and fuse portions 63 are provided.

[0053] The plurality of divided electrode portions 61 are divided by insulating slits 64 and are portions that will face the second metal layer 16 in the winding body 40.

[0054] The electrode portions 62 are adjacent to the plurality of divided electrode portions 61 with the insulating slits 64 interposed therebetween and are portions that do not face the second metal layer 16 in the winding body 40.

[0055] The fuse portions 63 are portions that connect the respective divided electrode portions 61 and electrode portions 62 and are thinner than the divided electrode portions 61 and the electrode portions 62.

[0056] The electrode pattern of the first metal layer 15 provided with the fuse portion, in addition to Figure 4 the electrode pattern shown, for example, may also be an electrode pattern disclosed in Japanese Patent Laid-Open No. 2004-363431, Japanese Patent Laid-Open No. 5-251266, etc. The same applies to the electrode pattern of the second metal layer 16 provided with the fuse portion.

[0057] The first external electrode 41 is provided on one end face of the winding body 40 and is connected to the first metal layer 15 by contacting the exposed end portion of the first metal layer 15.

[0058] From the viewpoint of the connectivity between the first metal layer 15 and the first external electrode 41, it is preferable that on one end face of the winding body 40, the first metallized film 11 protrudes in the width direction W with respect to the second metallized film 12.

[0059] The second external electrode 42 is provided on the other end face of the winding body 40 and is connected to the second metal layer 16 by contacting the exposed end portion of the second metal layer 16.

[0060] From the viewpoint of the connectivity between the second metal layer 16 and the second external electrode 42, it is preferable that on the other end face of the winding body 40, the second metallized film 12 protrudes in the width direction W with respect to the first metallized film 11.

[0061] As the constituent materials of the first external electrode 41 and the second external electrode 42, metals such as zinc, aluminum, tin, and zinc-aluminum alloy can be cited respectively.

[0062] The first external electrode 41 and the second external electrode 42 are each preferably formed by spraying a metal as described above on one end face and the other end face of the winding body 40.

[0063] The structure of the winding body 40 may also be different from Figure 2 the structure shown. For example, it may also be arranged such that in the first metallized film 11, the first metal layer 15 is divided into two metal layers in the width direction W, one metal layer reaching one side edge of the first dielectric film 13 and the other metal layer reaching the other side edge of the first dielectric film 13. In this case, if it is arranged such that in the first metal layer 15, one metal layer is connected to the first external electrode 41 and the other metal layer is connected to the second external electrode 42, and at the same time, the second metal layer 16 is not connected to both the first external electrode 41 and the second external electrode 42, a capacitor can be formed between the first metal layer 15 and the second metal layer 16.

[0064] In the thin film capacitor of the present invention, as the dielectric film, the thin film of the present invention can be used.

[0065] The thin film of the present invention includes a cured product of a first organic material having a hydroxyl group and a second organic material having an isocyanate group among aromatic compounds, and has a first main surface and a second main surface facing each other in the thickness direction.

[0066] Figure 5 is a top view schematic diagram showing an example of the thin film of the present invention. Figure 6 is shown in Figure 5 a cross-sectional schematic diagram of a portion corresponding to the line segment B1 - B2 in.

[0067] As shown in Figure 5 and Figure 6 the thin film (dielectric film) 110 has a first main surface 110a and a second main surface 110b facing each other in the thickness direction.

[0068] The thin film 110 includes a cured product of a first organic material having a hydroxyl group and a second organic material having an isocyanate group among aromatic compounds. More specifically, the thin film 110 includes a cured product having a urethane bond obtained by the reaction of the hydroxyl group (OH group) of the first organic material and the isocyanate group (NCO group) of the second organic material.

[0069] Regarding the presence of the urethane bond in the thin film, it can be confirmed by analysis using a Fourier transform infrared spectrophotometer (FT - IR).

[0070] The first organic material is preferably a polyol having a plurality of hydroxyl groups in the molecule.

[0071] As the polyol, for example, polyvinyl acetals such as polyvinyl acetal, polyether polyols such as phenoxy resin, polyester polyols, etc. can be cited.

[0072] As the polyol, phenoxy resin is preferred.

[0073] As the first organic material, a plurality of materials may also be used in combination.

[0074] The second organic material can also be said to be a so-called aromatic isocyanate among aromatic compounds having an isocyanate group.

[0075] The second organic material reacts with the hydroxyl group of the first organic material to form a crosslinked structure, and thus functions as a curing agent for curing the resin solution when manufacturing the thin film 110.

[0076] The second organic material is preferably a so-called aromatic polyisocyanate among aromatic compounds having a plurality of isocyanate groups in the molecule.

[0077] Examples of the aromatic polyisocyanate include diphenylmethane diisocyanate (MDI), toluene diisocyanate (TDI), etc. As the aromatic polyisocyanate, modified products of these aromatic polyisocyanates can also be used.

[0078] As the aromatic polyisocyanate, MDI is preferred. As MDI, for example, polymeric MDI or monomeric MDI can be used.

[0079] As the second organic material, a plurality of materials may also be used in combination.

[0080] In the thin film 110 Figure 2 In the thin film capacitor 10 shown, it can be used for both the first dielectric film 13 and the second dielectric film 14, or can be used for either the first dielectric film 13 or the second dielectric film 14. When the thin film 110 is used for Figure 2 both the first dielectric film 13 and the second dielectric film 14 of the thin film capacitor 10 shown, the compositions of the first dielectric film 13 and the second dielectric film 14 may be different from each other, but are preferably the same.

[0081] The thin film 110 is manufactured by applying a resin solution containing the first organic material and the second organic material to the surface of a substrate, drying it, and then curing it by heat treatment. The obtained thin film 110 is used in a state of being peeled off from the substrate.

[0082] In the thin film of the present invention, on the above-mentioned first main surface, there are a plurality of protrusions having the above-mentioned second organic material.

[0083] In Figure 5 and Figure 6 In the thin film 110 shown, a plurality of protrusions 120 are present on the first main surface 110a. In addition, a flat portion 130 is present on the first main surface 110a of the thin film 110, and the flat portion 130 does not have protrusions 120.

[0084] Regarding the presence of the protrusions, it can be confirmed as black-looking portions by observing the first main surface of the thin film using a scanning electron microscope (SEM).

[0085] The protrusion 120 has a second organic material, namely, aromatic isocyanate. More specifically, the aromatic isocyanate included in the protrusion 120 is derived from the aromatic isocyanate that constitutes the cured product included in the thin film 110.

[0086] Since the protrusion 120 has aromatic isocyanate, the hardness of the protrusion 120 becomes high due to the aromatic ring of the aromatic isocyanate. Therefore, when manufacturing a thin film capacitor using the thin film 110, even if the thin film 110 is wound or pressed after winding, the protrusion 120 is less likely to be damaged, and thus it becomes easy to form a gap between the mutually overlapping thin films 110. As a result, at the time of dielectric breakdown, the decomposition gas from the thin film 110 easily scatters from the inside of the thin film capacitor, and thus the self-healing property of the thin film capacitor becomes excellent.

[0087] In contrast, in the case where the protrusion 120 has aliphatic isocyanate, compared with the case where the protrusion 120 has aromatic isocyanate, the hardness of the protrusion 120 becomes low. Therefore, when manufacturing a thin film capacitor using the thin film 110, if the thin film 110 is wound or pressed after winding, the protrusion 120 is likely to be damaged, and thus it becomes difficult to form a gap between the mutually overlapping thin films 110. As a result, at the time of dielectric breakdown, the decomposition gas from the thin film 110 is less likely to scatter from the inside of the thin film capacitor, and thus the self-healing property of the thin film capacitor deteriorates.

[0088] In addition, even if the protrusion 120 has aromatic isocyanate, for example, in the first main surface 110a of the thin film 110, if the area ratio of the region higher than the thin film surface described later by 0.20 μm or more and less than 2.50 μm is less than 0.0998%, when manufacturing a thin film capacitor by winding the thin film 110, it becomes difficult to form a gap between the mutually overlapping thin films 110, and thus the self-healing property of the thin film capacitor also deteriorates.

[0089] Regarding the presence of aromatic isocyanate in the protrusions, it can be confirmed as follows. First, using a Fourier transform infrared spectrophotometer (FT-IR) "FT / IR-4100ST" manufactured by JASCO Corporation, the measurement wavenumber range is set to 500 cm -1 or more and 4000 cm -1Hereinafter, the infrared absorption spectrum of the protrusion is measured by the attenuated total reflection method (ATR). Then, in the infrared absorption spectrum of the protrusion, by confirming the detection of the absorption peaks of the aromatic ring and the isocyanate group, it is possible to confirm that the protrusion has an aromatic isocyanate. For example, in the case of using MDI as the aromatic isocyanate, in the infrared absorption spectrum, the absorption peak of the aromatic ring can be detected in the wavenumber range of 1450 cm -1 or higher and 1550 cm -1 or lower, and the absorption peak of the isocyanate group can be detected in the wavenumber range of 2200 cm -1 or higher and 2400 cm -1 or lower.

[0090] Furthermore, by the same method, in the infrared absorption spectrum of the flat part, by confirming the detection of the absorption peaks of the aromatic ring and the isocyanate group, it is possible to confirm that the aromatic isocyanate possessed by the protrusion is derived from the aromatic isocyanate constituting the cured product contained in the thin film.

[0091] In the thin film of the present invention, within the area of 100 μm × 140 μm on the first main surface, when defining the thin film surface at the average height in the thickness direction, the area ratio of the region in the range of 0.05 μm or more and less than 0.20 μm higher than the thin film surface is 6.04% or less, the area ratio of the region in the range of 0.20 μm or more and less than 2.50 μm higher than the thin film surface is 0.0998% or more and 1.13% or less, and the area ratio of the region in the range of 2.50 μm or more higher than the thin film surface is 0.100% or less.

[0092] In the thin film of the present invention, the area ratio of the region in the range of 0.05 μm or more and less than 0.20 μm higher than the thin film surface only needs to be 0.00% or more. In addition, the area ratio of the region in the range of 2.50 μm or more higher than the thin film surface only needs to be 0.000% or more.

[0093] In Figure 5 and Figure 6 the shown thin film 110, within the area of 100 μm × 140 μm on the first main surface 110a, when defining the thin film surface at the average height in the thickness direction, the area ratio of the region in the range of 0.05 μm or more and less than 0.20 μm higher than the thin film surface is 6.04% or less, the area ratio of the region in the range of 0.20 μm or more and less than 2.50 μm higher than the thin film surface is 0.0998% or more and 1.13% or less, and the area ratio of the region in the range of 2.50 μm or more higher than the thin film surface is 0.100% or less.

[0094] In order to improve the slidability when the thin films 110 slide relative to each other, it is important to reduce the contact area between the thin films 110. From such a perspective, in the thin film 110, as described above, a plurality of protrusions 120 are present on the first main surface 110a, and it is desired to reduce the contact area between the thin films 110 when the thin films 110 slide relative to each other. However, depending on the height distribution of the first main surface 110a of the thin film 110 having a plurality of protrusions 120, it may not be possible to achieve both slidability and withstand voltage. In response to this, regarding the height distribution of the first main surface 110a of the thin film 110, within the above-described area range, when defining the thin film surface at the average height in the thickness direction, the area ratio of the region in the range higher than the thin film surface by 0.05 μm or more and less than 0.20 μm is 6.04% or less, the area ratio of the region in the range higher than the thin film surface by 0.20 μm or more and less than 2.50 μm is 0.0998% or more and 1.13% or less, and the area ratio of the region in the range higher than the thin film surface by 2.50 μm or more is 0.100% or less, whereby the slidability and withstand voltage of the thin film 110 become excellent. Furthermore, since the slidability of the thin film 110 becomes excellent, when winding the thin film 110 to form a thin film capacitor, the pressability and self-healing properties are improved. It can be said that when the height distribution of the first main surface 110a of the thin film 110 is within the above-described range, a plurality of protrusions 120 having an appropriate height are distributed on the first main surface 110a in an appropriate proportion.

[0095] In the first main surface 110a of the thin film 110, when the area ratio of the region in the range higher than the thin film surface by 0.05 μm or more and less than 0.20 μm is higher than 6.04%, there will be more high protrusions 120 where the electric field is likely to concentrate, and thus the withstand voltage decreases.

[0096] In the first main surface 110a of the thin film 110, when the area ratio of the region in the range higher than the thin film surface by 0.20 μm or more and less than 2.50 μm is lower than 0.0998%, when the thin films 110 slide relative to each other, the contact area between the flat portions 130 is likely to become large, and thus the slidability decreases. In the first main surface 110a of the thin film 110, when the area ratio of the region in the range higher than the thin film surface by 0.20 μm or more and less than 2.50 μm is higher than 1.13%, there will be more high protrusions 120 where the electric field is likely to concentrate, and thus the withstand voltage decreases.

[0097] In the first main surface 110a of the thin film 110, when the area ratio of the region in the range higher than the thin film surface by 2.50 μm or more is higher than 0.100%, there will be more high protrusions 120 where the electric field is likely to concentrate, and thus the withstand voltage decreases.

[0098] Regarding the height distribution of the first major surface 110a of the thin film 110, as long as within the above-mentioned area range, when defining the thin film surface at the average height in the thickness direction, the area ratio of the area where the height is 0.05 μm or more and less than 0.20 μm higher than the thin film surface is 6.04% or less, the area ratio of the area where the height is 0.20 μm or more and less than 2.50 μm higher than the thin film surface is 0.0998% or more and 1.13% or less, and the area ratio of the area where the height is 2.50 μm or more higher than the thin film surface is 0.100% or less, then in addition to the multiple protrusions 120, multiple recesses can also exist on the first major surface 110a of the thin film 110.

[0099] The height distribution of the first major surface of the thin film can be determined as follows.

[0100] First, using the laser microscope "VK-8700" manufactured by Keyence Corporation, magnify the first major surface of the thin film by 100 times and observe an area range of 100 μm × 140 μm. At this time, aluminum with a thickness of 10 nm can also be pre-evaporated on the first major surface of the thin film. In addition, hereinafter, within the above-mentioned area range, the direction with a length of 100 μm is set as the first direction, and the direction with a length of 140 μm is set as the second direction.

[0101] Second, divide the above-mentioned area range into a total of 786,432 small cells (cells) of 1024 in the first direction × 768 in the second direction. Then, for each of the 786,432 divided small cells, use the dedicated analysis software "VK-analyzer" of the laser microscope "VK-8700" manufactured by Keyence Corporation to obtain the height data in the thickness direction (the average value of the height within the cell). Then, calculate the average value of the 786,432 height data, and use the obtained average value as the average height in the thickness direction in the thin film. In addition, define the imaginary surface at the average height in the thickness direction as the thin film surface.

[0102] Then, count the number J1 of cells having height data in the range where the height is 0.05 μm or more higher than the thin film surface, and calculate the area ratio K1 of the cells in the range where the height is 0.05 μm or more higher than the thin film surface as "100 × J1 / 786432". In addition, count the number J2 of cells having height data in the range where the height is 0.20 μm or more higher than the thin film surface, and calculate the area ratio K2 of the cells in the range where the height is 0.20 μm or more higher than the thin film surface as "100 × J2 / 786432". Furthermore, count the number J3 of cells having height data in the range where the height is 2.50 μm or more higher than the thin film surface, and calculate the area ratio K3 of the cells in the range where the height is 2.50 μm or more higher than the thin film surface as "100 × J3 / 786432".

[0103] Then, based on the obtained area ratios, the area ratio of the region in the range that is more than 0.05 μm and less than 0.20 μm higher than the film surface is calculated as "K1 - K2". In addition, the area ratio of the region in the range that is more than 0.20 μm and less than 2.50 μm higher than the film surface is calculated as "K2 - K3". Furthermore, the area ratio of the region in the range that is more than 2.50 μm higher than the film surface is set as "K3". In this way, the height distribution of the first main surface of the film is determined.

[0104] The planar shape of the protrusion 120 can be a circular shape as shown in Figure 5 , an elliptical shape, or other shapes.

[0105] The planar shapes of the protrusions 120 can be the same as each other or different from each other.

[0106] The cross-sectional shape of the protrusion 120 can be a conical shape as shown in Figure 6 , or a shape other than a conical shape.

[0107] The cross-sectional shapes of the protrusions 120 can be the same as each other or different from each other.

[0108] The top surface of the protrusion 120 is preferably recessed as shown in Figure 6 . In this case, when the films 110 slide relative to each other, the contact area between the protrusions 120 is likely to become smaller, so the slidability is likely to be improved. In addition, the top surface of the protrusion 120 may not be recessed.

[0109] In addition, the protrusion 120 can have a sharp front end or a rounded front end.

[0110] There are no protrusions on the second main surface 110b of the film 110, but there can also be multiple protrusions. In this case, regarding the height distribution of the second main surface 110b of the film 110, preferably, within the area of 100 μm × 140 μm of the second main surface 110b, when defining the film surface at the average height in the thickness direction, the area ratio of the region in the range that is more than 0.05 μm and less than 0.20 μm higher than the film surface is 6.04% or less, the area ratio of the region in the range that is more than 0.20 μm and less than 2.50 μm higher than the film surface is 0.0998% or more and 1.13% or less, and the area ratio of the region in the range that is more than 2.50 μm higher than the film surface is 0.100% or less. At this time, on the second main surface 110b of the film 110, in addition to multiple protrusions, there can also be multiple recesses.

[0111] The height distribution of the second main surface of the film can be determined in the same manner as the height distribution of the first main surface of the film, except that the object to be observed is the second main surface of the film.

[0112] In the film of the present invention, the coefficient of static friction on the first main surface side is preferably 1.0 or less.

[0113] In Figure 5 and Figure 6 In the film 110 shown, the coefficient of static friction on the first main surface 110a side is preferably 1.0 or less. In this case, the slidability of the film 110 becomes extremely excellent.

[0114] On the other hand, if the coefficient of static friction of the film 110 on the first main surface 110a side becomes too small, when winding the film 110 to manufacture a film capacitor, winding deviation of the film 110 will occur in the width direction, and in subsequent processes, it is sometimes difficult to form an external electrode on the end surface of the obtained wound body. From this point of view, the coefficient of static friction of the film 110 on the first main surface 110a side is preferably 0.1 or more.

[0115] The coefficient of static friction of the film can be determined as follows. First, as test specimens for measurement, prepare two films. Here, regarding the two main surfaces of each test specimen for measurement, at the time of manufacture, the main surface on the base material side is defined as the release surface, and the main surface on the side opposite to the base material is defined as the drying surface. More specifically, for each test specimen for measurement, the drying surface corresponds to the first main surface, and the release surface corresponds to the second main surface. In addition, the length direction of each test specimen for measurement is preferably the direction in which a tensile stress is applied to the film during the manufacture of the film capacitor, for example, the same as the winding direction of the film. Secondly, for one of the two test specimens for measurement, fix a square plate on the release surface so that the drying surface is exposed. In addition, for the other test specimen, paste a square counterweight with a weight of 200 g on the drying surface so that the release surface is exposed. Then, bring the release surface of the other test specimen in the state where the counterweight is pasted on the drying surface into contact with the drying surface of one test specimen in the state where the plate is fixed on the release surface so that the length directions are parallel to each other. Then, after installing the counterweight pasted on the drying surface of the other test specimen on a dynamometer manufactured by IMADA Co., Ltd., perform stretching at a speed of 150 mm / min in the length direction. At this time, read the maximum frictional force until the counterweight starts to move together with the other test specimen, and calculate the coefficient of static friction based on this value.

[0116] In the film 110, the glass transition temperature is preferably 130 °C or higher. In this case, the heat resistance of the film 110 becomes excellent, and the guaranteed temperature of the film capacitor including the film 110 can be increased to, for example, 125 °C or higher.

[0117] The glass transition temperature of the thin film can be determined as follows. First, using a dynamic viscoelasticity measurement (DMA) device "RSA-III" manufactured by TA Instruments, while heating the thin film from room temperature to 250°C at a heating rate of 10°C / min, the storage modulus and loss modulus of the thin film were measured under the measurement conditions where the measurement frequency was set to 10 rad / s and the strain was set to 0.1%. Then, the temperature at which the loss tangent (tanδ) expressed by the loss modulus / storage modulus shows the maximum peak was determined as the glass transition temperature.

[0118] The thickness S of the thin film 110 is preferably 1 μm or more and 10 μm or less, more preferably 3 μm or more and 5 μm or less.

[0119] As Figure 6 shown, the thickness S of the thin film is the thickness determined at a position where the protrusion 120 does not exist.

[0120] Regarding the thickness of the thin film, it can be measured using an optical film thickness meter.

[0121] The thin film of the present invention becomes a metallized thin film by providing a metal layer at least on the first main surface, and can constitute the thin film capacitor of the present invention.

[0122] Figure 7 is a top view schematic diagram showing an example of the metallized thin film constituting the thin film capacitor of the present invention. Figure 8 is shown with Figure 7 in the corresponding cross-sectional schematic diagram of the part corresponding to the line segment C1 - C2.

[0123] As Figure 7 and Figure 8 shown, the metallized thin film 210 has Figure 5 and Figure 6 shown the thin film 110, and a metal layer 220 provided on the first main surface 110a of the thin film 110.

[0124] In the thin film capacitor of the present invention, on the first main surface of the dielectric thin film, there are a plurality of protrusions having the second organic material.

[0125] In Figure 8 shown in the thin film 110, similar to the thin film 110 shown in Figure 5 and Figure 6 shown, on the first main surface 110a, there are a plurality of protrusions 120 having the second organic material, i.e., aromatic isocyanate. In addition, on the first main surface 110a of the thin film 110, there is a flat portion 130 where the protrusions 120 do not exist.

[0126] By having an aromatic isocyanate in the protrusion 120, a thin-film capacitor of a metallized thin film 210 having a metal layer 220 provided on the first main surface 110a of the thin film 110 can be made into a thin-film capacitor with excellent self-healing properties.

[0127] In the first mode of the thin-film capacitor of the present invention, within an area of 100 μm × 140 μm on the first main surface of the dielectric thin film, when defining the thin-film surface at the average height in the thickness direction, the area ratio of the region in the range of more than 0.05 μm and less than 0.20 μm higher than the thin-film surface is 6.04% or less, the area ratio of the region in the range of more than 0.20 μm and less than 2.50 μm higher than the thin-film surface is 0.0998% or more and 1.13% or less, and the area ratio of the region in the range of more than 2.50 μm higher than the thin-film surface is 0.100% or less. Thus, in the first mode of the thin-film capacitor of the present invention, attention is paid to the height distribution of the first main surface of the dielectric thin film where the above-mentioned multiple protrusions exist.

[0128] In the first mode of the thin-film capacitor of the present invention, the area ratio of the region in the range of more than 0.05 μm and less than 0.20 μm higher than the thin-film surface may be 0.00% or more. In addition, the area ratio of the region in the range of more than 2.50 μm higher than the thin-film surface may be 0.000% or more.

[0129] In Figure 8 the shown thin film 110, similar to Figure 5 and Figure 6 the shown thin film 110, within an area of 100 μm × 140 μm on the first main surface 110a, when defining the thin-film surface at the average height in the thickness direction, the area ratio of the region in the range of more than 0.05 μm and less than 0.20 μm higher than the thin-film surface is 6.04% or less, the area ratio of the region in the range of more than 0.20 μm and less than 2.50 μm higher than the thin-film surface is 0.0998% or more and 1.13% or less, and the area ratio of the region in the range of more than 2.50 μm higher than the thin-film surface is 0.100% or less.

[0130] By defining the film surface at the average height in the thickness direction within the above-mentioned area of the first main surface 110a of the film 110, the area ratio of the region with a height range of more than 0.05 μm and less than 0.20 μm higher than the film surface is 6.04% or less, the area ratio of the region with a height range of more than 0.20 μm and less than 2.50 μm higher than the film surface is 0.0998% or more and 1.13% or less, and the area ratio of the region with a height range of more than 2.50 μm higher than the film surface is 0.100% or less, so that the slidability and voltage resistance of the film 110 become excellent. Furthermore, since the slidability of the film 110 becomes excellent, when the film 110 is wound to form a film capacitor, the pressability and self-healing property are improved.

[0131] In a film capacitor, when measuring the height distribution of the first main surface of the film, for the region where no metal layer is provided on the metallized film located on the outermost surface of the film capacitor, the measurement is performed by the above method. At this time, when masking oil adheres to the surface of the measurement region, it is preferably measured in a state where the masking oil has been removed using a solvent such as hexane or toluene.

[0132] In the film capacitor of the present invention, the metallized film of the present invention can be used as the metallized film.

[0133] The metallized film of the present invention includes: a film containing a cured product of a first organic material having a hydroxyl group and a second organic material having an isocyanate group among aromatic compounds, and having a first main surface and a second main surface opposed to each other in the thickness direction; and a metal layer provided on at least the first main surface of the film. In addition, in the metallized film of the present invention, on the first main surface of the film, there are a plurality of protrusions having the second organic material. Furthermore, in the metallized film of the present invention, on the surface of the metal layer provided on the first main surface of the film, on the side opposite to the first main surface of the film, there are a plurality of convex portions along the plurality of protrusions.

[0134] In the first mode of the film capacitor of the present invention, similar to the second mode of the film capacitor of the present invention described later, it is preferable that on the surface of the metal layer provided on the first main surface of the dielectric film, on the side opposite to the first main surface of the dielectric film, there are a plurality of convex portions along the plurality of protrusions.

[0135] In the first mode of the thin film capacitor of the present invention, when the plurality of convex portions exist on the surface of the metal layer provided on the first main surface of the dielectric thin film, similar to the second mode of the thin film capacitor of the present invention described later, it is preferable that in the area of 100 μm × 140 μm on the surface of the metal layer, when defining the metal layer surface at the average height in the thickness direction, the area ratio of the region in the range of 0.05 μm or more and less than 0.20 μm higher than the metal layer surface is 6.17% or less, the area ratio of the region in the range of 0.20 μm or more and less than 2.50 μm higher than the metal layer surface is 0.118% or more and 1.24% or less, and the area ratio of the region in the range of 2.50 μm or more higher than the metal layer surface is 0.100% or less.

[0136] In the second mode of the thin film capacitor of the present invention, on the surface of the metal layer provided on the first main surface of the dielectric thin film, which is opposite to the first main surface of the dielectric thin film, there are a plurality of convex portions along the plurality of protrusions.

[0137] In Figure 7 and Figure 8 In the metallized thin film 210 shown, on the surface 220a of the metal layer 220, which is opposite to the first main surface 110a of the thin film 110, there are a plurality of convex portions 230 along the plurality of protrusions 120. In addition, there is a flat portion 240 on the surface 220a of the metal layer 220, and no convex portion 230 exists in the flat portion 240.

[0138] Regarding the existence of the convex portions, it can be confirmed as a dark-looking part by observing the surface of the metal layer using a scanning electron microscope.

[0139] In the metallized thin film of the present invention, in the area of 100 μm × 140 μm on the surface of the metal layer, when defining the metal layer surface at the average height in the thickness direction, the area ratio of the region in the range of 0.05 μm or more and less than 0.20 μm higher than the metal layer surface is 6.17% or less, the area ratio of the region in the range of 0.20 μm or more and less than 2.50 μm higher than the metal layer surface is 0.118% or more and 1.24% or less, and the area ratio of the region in the range of 2.50 μm or more higher than the metal layer surface is 0.100% or less.

[0140] In the metallized thin film of the present invention, the area ratio of the region in the range of 0.05 μm or more and less than 0.20 μm higher than the metal layer surface only needs to be 0.00% or more. In addition, the area ratio of the region in the range of 2.50 μm or more higher than the metal layer surface only needs to be 0.000% or more.

[0141] In the second mode of the thin-film capacitor of the present invention, within an area of 100 μm × 140 μm on the surface of the metal layer, when defining the metal layer surface at the average height in the thickness direction, the area ratio of the region with a height 0.05 μm or more and less than 0.20 μm higher than the metal layer surface is 6.17% or less, the area ratio of the region with a height 0.20 μm or more and less than 2.50 μm higher than the metal layer surface is 0.118% or more and 1.24% or less, and the area ratio of the region with a height 2.50 μm or more higher than the metal layer surface is 0.100% or less. Thus, in the second mode of the thin-film capacitor of the present invention, attention is paid to the height distribution of the surface of the metal layer where the plurality of convex portions exist.

[0142] In the second mode of the thin-film capacitor of the present invention, the area ratio of the region with a height 0.05 μm or more and less than 0.20 μm higher than the metal layer surface may be 0.00% or more. In addition, the area ratio of the region with a height 2.50 μm or more higher than the metal layer surface may be 0.000% or more.

[0143] In Figure 7 and Figure 8 In the metallized thin film 210 shown, within an area of 100 μm × 140 μm on the surface 220a of the metal layer 220, when defining the metal layer surface at the average height in the thickness direction, the area ratio of the region with a height 0.05 μm or more and less than 0.20 μm higher than the metal layer surface is 6.17% or less, the area ratio of the region with a height 0.20 μm or more and less than 2.50 μm higher than the metal layer surface is 0.118% or more and 1.24% or less, and the area ratio of the region with a height 2.50 μm or more higher than the metal layer surface is 0.100% or less.

[0144] When defining the metal layer surface at the average height in the thickness direction within the above-mentioned area range of the surface 220a of the metal layer 220, the area ratio of the region in the range more than 0.05 μm and less than 0.20 μm higher than the metal layer surface is 6.17% or less, the area ratio of the region in the range more than 0.20 μm and less than 2.50 μm higher than the metal layer surface is 0.118% or more and 1.24% or less, and the area ratio of the region in the range more than 2.50 μm higher than the metal layer surface is 0.100% or less, thereby the slidability and withstand voltage property of the metallized film 210 become excellent. Furthermore, since the slidability of the metallized film 210 becomes excellent, when winding the metallized film 210 to form a film capacitor, the pressability and self-healing property are improved. It can be said that when the height distribution of the surface 220a of the metal layer 220 is within the above-mentioned range, a plurality of convex portions 230 with appropriate heights are distributed on the surface 220a in an appropriate proportion.

[0145] In the surface 220a of the metal layer 220, when the area ratio of the region in the range more than 0.05 μm and less than 0.20 μm higher than the metal layer surface is higher than 6.17%, there will be more high convex portions 230 where the electric field is likely to concentrate, so the withstand voltage property decreases.

[0146] In the surface 220a of the metal layer 220, when the area ratio of the region in the range more than 0.20 μm and less than 2.50 μm higher than the metal layer surface is less than 0.118%, when sliding the metallized films 210 against each other, the contact area between the flat portions 240 is likely to become larger, so the slidability decreases. In the surface 220a of the metal layer 220, when the area ratio of the region in the range more than 0.20 μm and less than 2.50 μm higher than the metal layer surface is higher than 1.24%, there will be more high convex portions 230 where the electric field is likely to concentrate, so the withstand voltage property decreases.

[0147] In the surface 220a of the metal layer 220, when the area ratio of the region in the range more than 2.50 μm higher than the metal layer surface is higher than 0.100%, there will be more high convex portions 230 where the electric field is likely to concentrate, so the withstand voltage property decreases.

[0148] Regarding the height distribution of the surface 220a of the metal layer 220, as long as it is within the above-mentioned area range, when defining the metal layer surface at the average height in the thickness direction, the area ratio of the area where the height is more than 0.05 μm and less than 0.20 μm higher than the metal layer surface is 6.17% or less, the area ratio of the area where the height is more than 0.20 μm and less than 2.50 μm higher than the metal layer surface is 0.118% or more and 1.24% or less, and the area ratio of the area where the height is more than 2.50 μm higher than the metal layer surface is 0.100% or less, then in addition to the plurality of convex portions 230, a plurality of concave portions may also exist on the surface 220a of the metal layer 220.

[0149] The height distribution of the surface of the metal layer can be determined in the same manner as the height distribution of the first main surface of the thin film, except that the observation object is the surface of the metal layer.

[0150] In the thin film capacitor, when measuring the height distribution of the surface of the metal layer, the measurement is performed in a given area of the metallized thin film located on the outermost surface of the thin film capacitor.

[0151] In Figure 3 In the wound body 40 shown, it is preferable to measure the height distribution of the surface of the second metal layer 16 by the above method in the area L of the second metallized thin film 12 located on the outermost surface in the state where the second metal layer 16 is provided. Here, the area L of the second metallized thin film 12 is a square shape with a length of M in both the width direction W and the length direction (winding direction). In addition, when defining the center line Q that passes through the center point P of the end edge N of the second metallized thin film 12 and extends in the length direction, the area L of the second metallized thin film 12 is symmetric with respect to the center line Q in the width direction W. The length M of the area L of the second metallized thin film 12 is 10% of the length of the end edge N of the second metallized thin film 12.

[0152] In the metallized thin film of the present invention, the static friction coefficient on the surface side of the metal layer provided on the first main surface of the above thin film is preferably 1.4 or less.

[0153] In the first mode of the thin film capacitor of the present invention, when the plurality of convex portions exist on the surface of the metal layer provided on the first main surface of the dielectric thin film, the static friction coefficient on the surface side of the metal layer provided on the first main surface of the dielectric thin film is preferably 1.4 or less.

[0154] In the second mode of the thin film capacitor of the present invention, the static friction coefficient on the surface side of the metal layer provided on the first main surface of the dielectric thin film is preferably 1.4 or less.

[0155] In Figure 7 AndFigure 8 In the metallized film 210 shown, the coefficient of static friction of the metal layer 220 on the surface 220a side is preferably 1.4 or less. In this case, the slidability of the metallized film 210 becomes very excellent.

[0156] On the other hand, in the metallized film 210, if the coefficient of static friction of the metal layer 220 on the surface 220a side becomes too small, when winding the metallized film 210 to manufacture a film capacitor, winding deviation of the metallized film 210 will occur in the width direction, and in subsequent processes, it sometimes becomes difficult to form an external electrode on the end face of the obtained wound body. From such a viewpoint, in the metallized film 210, the coefficient of static friction of the metal layer 220 on the surface 220a side is preferably 0.2 or more.

[0157] The coefficient of static friction of the metallized film can be determined in the same manner as the coefficient of static friction of the film, except that the metallized film is used as a measurement sample.

[0158] As a constituent material of the metal layer 220, for example, metals such as aluminum, zinc, titanium, magnesium, tin, and nickel can be cited.

[0159] The thickness of the metal layer 220 is preferably 5 nm or more and 40 nm or less.

[0160] Regarding the thickness of the metal layer, it can be determined by observing a cross section in the thickness direction of the metallized film using a transmission electron microscope (TEM).

[0161] The film of the present invention can be manufactured, for example, by the following method.

[0162] <Production process of resin solution>

[0163] A resin solution is prepared by mixing a first organic material having a hydroxyl group and a second organic material having an isocyanate group among aromatic compounds.

[0164] As the first organic material and the second organic material, the above-mentioned materials can be used.

[0165] When preparing the resin solution, the first organic material and the second organic material can also be diluted with a solvent. In particular, it is preferable to dilute the first organic material and the second organic material with a mixed solvent containing a first solvent selected from ketones and a second solvent selected from cyclic ether compounds.

[0166] As the ketones for selecting the first solvent, for example, methyl ethyl ketone, diethyl ketone, etc. can be cited.

[0167] As the first solvent, a plurality of ketones can also be used in combination.

[0168] As the cyclic ether compound for the second solvent, for example, tetrahydrofuran, tetrahydropyran, etc. can be cited.

[0169] As the second solvent, a plurality of cyclic ether compounds can also be used in combination.

[0170] As the solvent, a mixed solvent containing methyl ethyl ketone and tetrahydrofuran is preferably used.

[0171] <Drying / Curing Process of Resin Solution>

[0172] First, the resin solution is applied to the surface of the substrate.

[0173] As the substrate, for example, polyethylene terephthalate film, polypropylene film, etc. can be cited.

[0174] Next, after drying the coating film of the obtained resin solution with a drying furnace, it is cured by heat treatment. Thus, a film is produced on the surface of the substrate.

[0175] At this time, for the coating film of the resin solution, the drying temperature, drying time, air volume, etc. in the drying furnace are adjusted, whereby the second organic material, i.e., aromatic isocyanate, is condensed on the drying surface, which is the main surface on the side opposite to the substrate, of the coating film, and a plurality of protrusions are generated as its condensate. Further, the height of these protrusions is controlled. As a result, in the state of the film obtained by curing the coating film, the height distribution of the first main surface of the film corresponding to the drying surface can be controlled such that in the area of 100 μm × 140 μm of the first main surface, when defining the film surface at the average height in the thickness direction, the area ratio of the region where the height is more than 0.05 μm and less than 0.20 μm higher than the film surface is 6.04% or less, the area ratio of the region where the height is more than 0.20 μm and less than 2.50 μm higher than the film surface is 0.0998% or more and 1.13% or less, and the area ratio of the region where the height is more than 2.50 μm higher than the film surface is 0.100% or less.

[0176] The drying temperature of the coating film is preferably adjusted within the range of 70°C or higher and 150°C or lower.

[0177] The drying time of the coating film can be adjusted by the conveying speed of the substrate conveying the coating film in the drying furnace. The conveying speed is preferably adjusted within the range of 100 m / min or higher and 160 m / min or lower.

[0178] In addition, the obtained film is used in the state of being peeled off from the substrate. As described above, the first main surface of the film corresponds to the drying surface, which is the main surface on the side opposite to the substrate, in the coating film. In addition, the second main surface of the film corresponds to the demolding surface, which is the main surface on the substrate side, in the coating film.

[0179] According to the above, produce asFigure 5 and Figure 6 the thin films shown.

[0180] The metallized thin film of the present invention can be manufactured, for example, by the following method.

[0181] <Manufacturing Process of Metallized Thin Film>

[0182] First, by the manufacturing method of the thin film of the present invention described above, as the first dielectric thin film and the second dielectric thin film, thin films as shown in Figure 5 and Figure 6 are manufactured.

[0183] Next, a first metal layer is formed by vapor-depositing a metal on the first main surface of the first dielectric thin film, thereby manufacturing a first metallized thin film. At this time, the first metal layer is formed such that on the surface of the first metal layer on the side opposite to the first main surface of the first dielectric thin film, there are a plurality of convex portions along the plurality of protrusions of the first dielectric thin film. Furthermore, the first metal layer is formed such that in the width direction, it reaches one side edge of the first dielectric thin film and does not reach the other side edge of the first dielectric thin film.

[0184] In addition, a second metal layer is formed by vapor-depositing a metal on the first main surface of the second dielectric thin film, thereby manufacturing a second metallized thin film. At this time, the second metal layer is formed such that on the surface of the second metal layer on the side opposite to the first main surface of the second dielectric thin film, there are a plurality of convex portions along the plurality of protrusions of the second dielectric thin film. Furthermore, the second metal layer is formed such that in the width direction, it does not reach one side edge of the second dielectric thin film and reaches the other side edge of the second dielectric thin film.

[0185] Through this process, as the first metallized thin film and the second metallized thin film, metallized thin films as shown in Figure 7 and Figure 8 are manufactured.

[0186] The thin film capacitor of the present invention can be manufactured, for example, by the following method.

[0187] <Manufacturing Process of Winding Body>

[0188] First, by the manufacturing method of the metallized thin film of the present invention described above, as the first metallized thin film and the second metallized thin film, metallized thin films as shown in Figure 7 and Figure 8 are manufactured.

[0189] Next, the first metallized thin film and the second metallized thin film are overlapped in a state where they are offset by a given distance in the width direction and then wound, thereby manufacturing a winding body. Additionally, if necessary, the obtained winding body can also be pressed into an elliptical cylindrical shape by clamping it from the direction perpendicular to the width direction.

[0190] <Formation process of external electrodes>

[0191] The first external electrode is formed by spraying metal on one end face of the wound body, so as to be connected to the first metal layer.

[0192] In addition, the second external electrode is formed by spraying metal on the other end face of the wound body, so as to be connected to the second metal layer.

[0193] According to the above, a thin film capacitor as Figure 1 and Figure 2 shown is manufactured.

[0194] The thin film capacitor of the present invention can be applied to known uses. However, since it is possible to achieve a long service life of equipment used in an environment with a large temperature change at high temperatures, it is suitable for use in power electronic devices such as electric compressors / pumps, chargers, DC-DC converters, and drive inverters mounted on automobiles and industrial equipment.

[0195] [Examples]

[0196] Hereinafter, examples more specifically disclosing the thin film capacitor of the present invention, the thin film of the present invention, and the metallized thin film of the present invention are shown. In addition, the present invention is not limited to these examples.

[0197] Thin film specimens 1 to 7 were manufactured by the following method.

[0198] <Production process of resin solution>

[0199] A resin solution was prepared by diluting and mixing phenoxy resin and MDI with a mixed solvent of methyl ethyl ketone and tetrahydrofuran.

[0200] <Drying / curing process of resin solution>

[0201] First, the resin solution was coated on the surface of a polyethylene terephthalate film using a gravure coater.

[0202] Secondly, after drying the coating film of the obtained resin solution with a drying furnace, it was cured by heat treatment for a certain period of time. Thus, thin film specimens 1 to 7 with a thickness of 4.5 μm were produced on the surface of the polyethylene terephthalate film.

[0203] At this time, for the coating film of the resin solution, by adjusting the drying temperature within the range of 70°C or higher and 150°C or lower, and in addition, adjusting the conveyance speed in the drying furnace within the range of 100 m / min or higher and 160 m / min or lower, the generation state of the protrusions having MDI was controlled in the first main surface of the film specimen. Further, the height of the protrusions and the like were controlled. Thus, the height distribution of the first main surface of the film specimen differed among film specimens 1 to 7.

[0204] Then, the obtained film specimens 1 to 7 were peeled off from the polyethylene terephthalate film.

[0205] In addition, in the resin solution used for manufacturing the film specimens 1 to 7, hexamethylene diisocyanate (HDI) as an aliphatic polyisocyanate was blended in place of MDI, and the film specimen 8 was manufactured by the same method as that for the film specimens 1 to 7.

[0206] In addition, using the same resin solution as that used for manufacturing the film specimens 1 to 7, a film specimen 9 having no protrusions on the first main surface was manufactured. Further, a filler was further blended in the resin solution used for manufacturing the film specimen 9, and the blending ratio of the filler was changed, whereby the film specimens 10 to 12 were manufactured. Regarding the blending ratio of the filler, it was set to 1% by weight in the film specimen 10, 3% by weight in the film specimen 11, and 10% by weight in the film specimen 12 with respect to the total weight of the phenoxy resin and MDI. As the filler, acrylic beads “MP - 1451” (average particle diameter: 0.15 μm) manufactured by Soken Chemical & Engineering Co., Ltd. were used.

[0207] [Evaluation]

[0208] Regarding the film specimens 1 to 7, it was confirmed by the above method that the protrusions had MDI. Regarding the film specimen 8, it was confirmed that the protrusions had HDI. Regarding the film specimen 9, it was confirmed that there were no protrusions on the first main surface. Regarding the film specimens 10 to 12, it was confirmed that the first main surface was rough due to the filler.

[0209] Furthermore, the following evaluations were performed on the film specimens 1 to 12. The results are shown in Table 1. In addition, in Table 1, the film specimens are simply described as “specimen”.

[0210] <Height distribution>

[0211] Regarding the thin film specimens 1 to 12, by the above method, as the height distribution of the first main surface of the thin film specimen, the area ratio of the region in the range of more than 0.05 μm and less than 0.20 μm higher than the thin film surface, the area ratio of the region in the range of more than 0.20 μm and less than 2.50 μm higher than the thin film surface, and the area ratio of the region in the range of more than 2.50 μm higher than the thin film surface were measured. In addition, in Table 1, the area ratio of the region in the range of more than 0.05 μm and less than 0.20 μm higher than the thin film surface was recorded as "area ratio 1", the area ratio of the region in the range of more than 0.20 μm and less than 2.50 μm higher than the thin film surface was recorded as "area ratio 2", and the area ratio of the region in the range of more than 2.50 μm higher than the thin film surface was recorded as "area ratio 3".

[0212] In addition, a metal layer was formed by vapor-depositing aluminum on the first main surface of the thin film specimens 1 to 12, thereby fabricating a metallized thin film. Then, regarding the obtained metallized thin film, by the above method, as the height distribution of the surface of the metal layer, the area ratio of the region in the range of more than 0.05 μm and less than 0.20 μm higher than the metal layer surface, the area ratio of the region in the range of more than 0.20 μm and less than 2.50 μm higher than the metal layer surface, and the area ratio of the region in the range of more than 2.50 μm higher than the metal layer surface were measured. In addition, in Table 1, the area ratio of the region in the range of more than 0.05 μm and less than 0.20 μm higher than the metal layer surface was recorded as "area ratio 1'", the area ratio of the region in the range of more than 0.20 μm and less than 2.50 μm higher than the metal layer surface was recorded as "area ratio 2'", and the area ratio of the region in the range of more than 2.50 μm higher than the metal layer surface was recorded as "area ratio 3'".

[0213] <Glass transition temperature>

[0214] Regarding the thin film specimens 1 to 8, the glass transition temperature was measured by the above method.

[0215] <Coefficient of static friction 1>

[0216] Regarding the thin film specimens 1 to 12, the coefficient of static friction was measured by the above method. In addition, in Table 1, the coefficient of static friction in the state of the thin film was recorded as "coefficient of static friction 1".

[0217] <Coefficient of static friction 2>

[0218] A metal layer was formed by vapor-depositing aluminum on the first main surface of the thin film specimens 1 to 12, thereby fabricating a metallized thin film. Then, regarding the obtained metallized thin film, the coefficient of static friction was measured by the above method. In addition, in Table 1, the coefficient of static friction in the state of the metallized thin film was recorded as "coefficient of static friction 2".

[0219] <Insulation breakdown voltage>

[0220] First, a measurement sample was fabricated by vapor-depositing aluminum on both main surfaces of film samples 1 to 12 to form a metal layer. At this time, the area of the region where the metal layers vapor-deposited on both main surfaces of the film sample overlapped each other was set to 3 cm 2 . For each of the film samples 1 to 12, 16 such measurement samples were fabricated. Second, for the 16 measurement samples, each electric field strength was maintained for 10 minutes at a scale of 25 V / μm, and the electric field strength at which 8 breakdown marks occurred in the film sample was set as the failure voltage. Regarding the measurement temperature, it was set to 125°C. Then, a Weibull plot was made for the failure voltages of the 16 measurement samples, and the value at which the failure frequency became 50% in this Weibull distribution was adopted as the insulation breakdown voltage of the film sample.

[0221] <Suppressibility>

[0222] First, a metallized film was fabricated by vapor-depositing aluminum on the first main surface of film samples 1 to 12 to form a metal layer. At this time, in order to make the metal layer patterned, a fluorine-based oil was pre-coated on the first main surface of the film sample. Second, after cutting the metallized film into a given width, it was wound cylindrically by a given length to fabricate a wound body. Then, according to the size of the wound body, after pressing the wound body while appropriately adjusting the pressing force in the range of 10 N or more and 100 N or less, the wound body was evaluated for whether it was uniformly pressed. Regarding the evaluation index, when observing the wound body from the width direction (refer to Figure 3 ), the case where the film along the inner side of the void portion at the center of the winding had no wrinkles / fractures was set as ○ (good), and the case where the film along the inner side of the void portion at the center of the winding had wrinkles / fractures was set as × (bad).

[0223] <Self-healing property>

[0224] First, a metallized film was fabricated by vapor-depositing aluminum on the first main surface of film samples 1 to 12 to form a metal layer. At this time, in order to make the metal layer patterned, a fluorine-based oil was pre-coated on the first main surface of the film sample. Second, after cutting the metallized film into a given width, it was wound cylindrically by a given length to fabricate a wound body. Then, external electrodes were formed by spraying metal on both end faces of the obtained wound body to fabricate a film capacitor. Then, while applying a voltage to the obtained film capacitor, the applied voltage was gradually increased, and it was evaluated whether it returned to the original applied voltage even when the applied voltage dropped instantaneously at the time of insulation breakdown. Regarding the evaluation index, the case where it returned to the original applied voltage was set as ○ (good), and the case where it did not return to the original applied voltage was set as × (bad).

[0225] [Table 1]

[0226]

[0227] In Table 1, the specimens with * in the specimen name are comparative examples outside the scope of the present invention.

[0228] Based on the above, in thin film specimens 1 to 3, it was confirmed that protrusions having aromatic isocyanate exist on the first main surface. Further, it was confirmed that area ratio 1 is 6.04% or less, area ratio 2 is 0.0998% or more and 1.13% or less, and area ratio 3 is 0.100% or less. In addition, in the state where a metal layer was vapor-deposited on the first main surface of thin film specimens 1 to 3 to form a metallized film, regarding the height distribution of the surface of the metal layer, it was confirmed that area ratio 1' is 6.17% or less, area ratio 2' is 0.118% or more and 1.24% or less, and area ratio 3' is 0.100% or less. From such thin film specimens 1 to 3, excellent slidability and withstand voltage properties can be obtained. Furthermore, the pressability and self-healing properties of the thin film capacitor can be made excellent. More specifically, from thin film specimens 1 to 3, very excellent slidability due to low coefficient of static friction 1 and coefficient of static friction 2, and very excellent withstand voltage properties with an insulation breakdown voltage of 300 V / μm or more can be obtained. Furthermore, the pressability and self-healing properties of the thin film capacitor can be made excellent. In addition, in thin film specimens 1 to 3, the glass transition temperature is 130°C or higher, and the heat resistance is also excellent.

[0229] In thin film specimen 4, area ratio 2 is less than 0.0998%. In addition, in the state where a metal layer was vapor-deposited on the first main surface of thin film specimen 4 to form a metallized film, area ratio 2' is less than 0.118%. Therefore, based on thin film specimen 4, compared with thin film specimens 1 to 3, coefficient of static friction 1 and coefficient of static friction 2 become higher, and the pressability and self-healing properties of the thin film capacitor cannot be made excellent.

[0230] In thin film specimen 5, area ratio 2 is higher than 1.13%. In addition, in the state where a metal layer was vapor-deposited on the first main surface of thin film specimen 5 to form a metallized film, area ratio 2' is higher than 1.24%. Therefore, based on thin film specimen 5, compared with thin film specimens 1 to 3, the insulation breakdown voltage becomes lower.

[0231] In thin film specimen 6, area ratio 1 is higher than 6.04%. In addition, in the state where a metal layer was vapor-deposited on the first main surface of thin film specimen 6 to form a metallized film, area ratio 1' is higher than 6.17%. Therefore, based on thin film specimen 6, compared with thin film specimens 1 to 3, the insulation breakdown voltage becomes lower.

[0232] In the thin film sample 7, the area ratio 3 is higher than 0.100%. Further, in the state where a metal layer is vapor-deposited on the first main surface of the thin film sample 7 to form a metallized film, the area ratio 3' is higher than 0.100%. Therefore, based on the thin film sample 7, compared with the thin film samples 1 to 3, the dielectric breakdown voltage is lower.

[0233] In the thin film sample 8, the protrusion has an aliphatic isocyanate, and thus the self-healing property of the thin film capacitor cannot be made excellent.

[0234] In the thin film sample 9, there are no protrusions. Further, in the state where a metal layer is vapor-deposited on the first main surface of the thin film sample 9 to form a metallized film, there are no convex portions. Therefore, based on the thin film sample 9, compared with the thin film samples 1 to 3, the static friction coefficient 1 and the static friction coefficient 2 are higher, and the pressing property and the self-healing property of the thin film capacitor cannot be made excellent. In addition, in the thin film sample 9, the first main surface is gently recessed as a whole, and thus the area ratio 1 and the area ratio 2 are not 0%. Further, in the state where a metal layer is vapor-deposited on the first main surface of the thin film sample 9 to form a metallized film, the surface of the metal layer is gently recessed as a whole, and thus the area ratio 1' and the area ratio 2' are not 0%.

[0235] In the thin film samples 10 to 12, a filler is incorporated, and thus, compared with the thin film samples 1 to 3, the dielectric breakdown voltage is low. Further, based on the thin film sample 10, compared with the thin film samples 1 to 3, the static friction coefficient 1 and the static friction coefficient 2 are higher, and the pressing property and the self-healing property of the thin film capacitor cannot be made excellent.

[0236] Description of Reference Numerals

[0237] 10 Thin film capacitor;

[0238] 11 First metallized film;

[0239] 12 Second metallized film;

[0240] 13 First dielectric film;

[0241] 13a First main surface of the first dielectric film;

[0242] 13b Second main surface of the first dielectric film;

[0243] 14 Second dielectric film;

[0244] 14a First main surface of the second dielectric film;

[0245] 14b Second main surface of the second dielectric film;

[0246] 15 First metal layer;

[0247] 16 Second metal layer;

[0248] 40 Winding body;

[0249] 41 First external electrode;

[0250] 42 Second external electrode;

[0251] 61 Divided electrode part;

[0252] 62 Electrode part;

[0253] 63 Fuse part;

[0254] 64 Insulating slit;

[0255] 110 Thin film (dielectric thin film);

[0256] 110a First main surface of the thin film;

[0257] 110b Second main surface of the thin film;

[0258] 120 Protrusion of the thin film;

[0259] 130 Flat part of the thin film;

[0260] 210 Metallized thin film;

[0261] 220 Metal layer;

[0262] 220a Surface of the metal layer;

[0263] 230 Convex part of the metal layer;

[0264] 240 Flat part of the metal layer;

[0265] L Region of the second metallized thin film;

[0266] M Length of the region of the second metallized thin film;

[0267] N Edge of the second metallized thin film;

[0268] P Center point of the edge of the second metallized thin film;

[0269] Q Center line;

[0270] S Thickness of the thin film;

[0271] T Laminating direction;

[0272] W Width direction.

Claims

1. A thin film capacitor, characterized in that, it includes a wound body formed by winding a dielectric film and a metal layer. The dielectric film contains a cured product of a first organic material having a hydroxyl group and a second organic material having an isocyanate group among aromatic compounds, and has a first main surface and a second main surface facing each other in the thickness direction. The metal layer is provided on at least the first main surface of the dielectric film. On the first main surface of the dielectric film, there are a plurality of protrusions having the second organic material. In the area of 100 μm × 140 μm on the first main surface of the dielectric film, when defining the film surface at the average height in the thickness direction, the area ratio of the region in the range of 0.05 μm or more and less than 0.20 μm higher than the film surface is 6.04% or less, the area ratio of the region in the range of 0.20 μm or more and less than 2.50 μm higher than the film surface is 0.0998% or more and 1.13% or less, and the area ratio of the region in the range of 2.50 μm or more higher than the film surface is 0.100% or less.

2. The thin film capacitor according to claim 1, characterized in that, on the surface of the metal layer provided on the first main surface of the dielectric film, which is opposite to the first main surface of the dielectric film, there are a plurality of convex portions along the plurality of protrusions.

3. The thin film capacitor according to claim 2, characterized in that, the static friction coefficient of the metal layer provided on the first main surface of the dielectric film on the surface side is 1.4 or less.

4. The thin film capacitor according to any one of claims 1 to 3, characterized in that, when observing the cross-section of the wound body perpendicular to the reel direction, the cross-sectional shape of the wound body is a flat shape.

5. A thin film capacitor, characterized in that, it includes a wound body formed by winding a dielectric film and a metal layer. The dielectric film contains a cured product of a first organic material having a hydroxyl group and a second organic material having an isocyanate group among aromatic compounds, and has a first main surface and a second main surface facing each other in the thickness direction. The metal layer is provided on at least the first main surface of the dielectric film. On the first main surface of the dielectric film, there are a plurality of protrusions having the second organic material. On the surface of the metal layer provided on the first main surface of the dielectric film, which is opposite to the first main surface of the dielectric film, there are a plurality of convex portions along the plurality of protrusions. Within an area of 100 μm × 140 μm on the surface of the metal layer, when defining the metal layer surface at the average height in the thickness direction, the area ratio of the region with a height more than 0.05 μm and less than 0.20 μm above the metal layer surface is 6.17% or less, the area ratio of the region with a height more than 0.20 μm and less than 2.50 μm above the metal layer surface is 0.118% or more and 1.24% or less, and the area ratio of the region with a height more than 2.50 μm above the metal layer surface is 0.100% or less.

6. The thin film capacitor according to claim 5, wherein, the coefficient of static friction on the surface side of the metal layer provided on the first main surface of the dielectric film is 1.4 or less.

7. The thin film capacitor according to claim 5 or 6, wherein, when observing a cross-section of the wound body perpendicular to the reel axis direction, the cross-sectional shape of the wound body is a flat shape.

8. A thin film, wherein, it contains a cured product of a first organic material having a hydroxyl group and a second organic material having an isocyanate group among aromatic compounds, and has a first main surface and a second main surface opposed to each other in the thickness direction, on the first main surface, there are a plurality of protrusions having the second organic material, within an area of 100 μm × 140 μm on the first main surface, when defining the thin film surface at the average height in the thickness direction, the area ratio of the region with a height more than 0.05 μm and less than 0.20 μm above the thin film surface is 6.04% or less, the area ratio of the region with a height more than 0.20 μm and less than 2.50 μm above the thin film surface is 0.0998% or more and 1.13% or less, and the area ratio of the region with a height more than 2.50 μm above the thin film surface is 0.100% or less.

9. The thin film according to claim 8, wherein, the coefficient of static friction on the first main surface side is 1.0 or less.

10. A metallized thin film, wherein, it comprises: a thin film containing a cured product of a first organic material having a hydroxyl group and a second organic material having an isocyanate group among aromatic compounds, and having a first main surface and a second main surface opposed to each other in the thickness direction; and a metal layer provided on at least the first main surface of the thin film, on the first main surface of the thin film, there are a plurality of protrusions having the second organic material, on the surface of the metal layer provided on the first main surface of the thin film, on the side opposite to the first main surface of the thin film, there are a plurality of convex portions along the plurality of protrusions. Within the area of 100 μm × 140 μm on the surface of the metal layer, when defining the metal layer surface at the average height in the thickness direction, the area ratio of the region with a height more than 0.05 μm and less than 0.20 μm above the metal layer surface is 6.17% or less, the area ratio of the region with a height more than 0.20 μm and less than 2.50 μm above the metal layer surface is 0.118% or more and 1.24% or less, and the area ratio of the region with a height more than 2.50 μm above the metal layer surface is 0.100% or less.

11. The metallized film according to claim 10, wherein the static friction coefficient on the surface side of the metal layer provided on the first main surface of the film is 1.4 or less.

Images