Thin film capacitor, thin film for thin film capacitor, and metallized thin 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 exist on the first main surface (110a) of the dielectric film (110). In the area of 100 μm × 140 μm on the first main surface (110a) of the dielectric film (110), the skewness of the first main surface (110a) of the dielectric film (110) is 0.782 or more and 14.3 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 a wound body, if a gap is formed between the mutually overlapping thin films, at the time of dielectric breakdown, the decomposition gas from the thin film becomes easy to scatter from the inside of the thin film capacitor. As a result, the insulating state of the thin film is restored, that is, a so-called self-healing function is made to work. When making a wound body, if the slidability of the thin film is good, a gap is easy to be uniformly formed between the mutually overlapping thin films, and thus the self-healing function is easy to work.

[0005] Based on the above, in order to improve the pressability and self-healing property of a 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 has been 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 Unexamined Patent Application Publication No. 2011-251493 Summary of the Invention

[0009] Problems to be Solved by the Invention

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

[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 easy to form gaps between the mutually overlapping thin films. Therefore, it can be considered that the self-healing function becomes easy 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, 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. Furthermore, 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 in that it includes a wound body obtained by winding a dielectric film and a metal layer, the dielectric film 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 opposed to 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, and in an area of 100 μm × 140 μm on the first main surface of the dielectric film, the skewness of the first main surface of the dielectric film is 0.782 or more and 14.3 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 opposed to 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. In an area of 100 μm × 140 μm on the surface of the metal layer, the skewness of the surface of the metal layer is 0.562 or more and 13.9 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 opposed to each other in the thickness direction. On the first main surface, there are a plurality of protrusions having the second organic material. In an area of 100 μm × 140 μm on the first main surface, the skewness of the first main surface is 0.782 or more and 14.3 or less.

[0018] The metallized thin film of the present invention is characterized by comprising: 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, which is opposite to the first main surface of the thin film, there are a plurality of convex portions along the plurality of protrusions. In an area of 100 μm × 140 μm on the surface of the metal layer, the skewness of the surface of the metal layer is 0.562 or more and 13.9 or less.

[0019] Advantages of the Invention

[0020] According to the present invention, it is possible to provide a thin film capacitor with a dielectric film having 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 thin 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 thin film that can be used in the above thin film capacitor. Description of the Drawings

[0021] Figure 1It is a three-dimensional schematic diagram showing an example of the thin-film capacitor of the present invention.

[0022] Figure 2 It is a cross-sectional schematic diagram showing the part corresponding to the line segment A1 - A2 in Figure 1 ...

[0023] Figure 3 It is a three-dimensional schematic diagram showing Figure 1 and Figure 2 an example of the winding body in

[0024] Figure 4 It is a top view schematic diagram showing an example of the metal layer provided with a fuse part.

[0025] Figure 5 It is a top view schematic diagram showing an example of the thin film of the present invention.

[0026] Figure 6 It is a cross-sectional schematic diagram showing the part corresponding to the line segment B1 - B2 in Figure 5 ...

[0027] Figure 7 It 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 It is a cross-sectional schematic diagram showing the part corresponding to the line segment C1 - C2 in Figure 7 ... Detailed Embodiments

[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. Furthermore, 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 winding body formed by winding a dielectric film and a metal layer. The dielectric film 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. The metal layer is provided on at least the first main surface of the dielectric film.

[0031] When not 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 metallized films having metal layers provided on at least one main surface of a dielectric thin film are wound in a stacked state will be described.

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

[0034] In this specification, as shown in Figure 1 , Figure 2 , and Figure 3 , the stacking direction and the width direction in the thin film capacitor are respectively set as the directions determined by T and W. In addition, in the wound type thin film capacitor, it can also 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 shown in Figure 1 and Figure 2 , the thin 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 shown in Figure 2 and Figure 3 , the wound body 40 is a wound body in which a first metallized film 11 and a second metallized film 12 are wound in a stacked state in the stacking direction T. That is, the thin film capacitor 10 is a wound type thin film capacitor having the wound body 40.

[0037] In the thin film capacitor 10, from the viewpoint of reducing the height of the thin film capacitor 10, it is preferable that when observing a cross-section of the wound body perpendicular to the reel 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 thin film capacitor 10 may also have a cylindrical winding axis. The winding axis is disposed on the central axis of the wound first metallized thin film 11 and second metallized thin film 12, and serves as a reel when winding the first metallized thin film 11 and the second metallized thin film 12.

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

[0041] The first dielectric thin 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).

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

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

[0044] The second dielectric thin 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 thin film 14. More specifically, the second metal layer 16 is provided to not reach one side edge of the second dielectric thin film 14 in the width direction W and reach the other side edge of the second dielectric thin film 14.

[0046] In the wound body 40, the adjacent first metallized thin film 11 and second metallized thin 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 thin 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 thin film 14 is exposed on the other end face of the wound body 40.

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

[0048] In the winding body 40, the first metallized film 11 and the second metallized film 12 are wound in a stacked state 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 be provided not on the first main surface 14a of the second dielectric film 14 but on the second main surface 13b of the first dielectric film 13. In this case, in the winding body 40, a metallized film in which the first metal layer 15 is provided on the first main surface 13a of the first dielectric film 13 and the second metal layer 16 is provided on the second main surface 13b, and the second dielectric film 14 are wound in a stacked state in the stacking direction T.

[0050] Preferably, fuse portions are provided on the first metal layer 15 and the second metal layer 16, respectively.

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

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

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

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

[0055] The fuse portion 63 is a portion that connects each divided electrode portion 61 and the electrode portion 62 and is thinner than the divided electrode portion 61 and the electrode portion 62.

[0056] The electrode pattern of the first metal layer 15 provided with the fuse portion is, in addition to Figure 4 the electrode pattern shown, for example, an electrode pattern disclosed in Japanese Patent Application Laid-Open No. 2004-363431, Japanese Patent Application 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 wound body 40, the first metallized film 11 protrudes from the second metallized film 12 in the width direction W.

[0059] The second external electrode 42 is provided on the other end face of the wound 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 wound body 40, the second metallized film 12 protrudes from the first metallized film 11 in the width direction W.

[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 wound body 40.

[0063] The structure of the wound body 40 can also be different from Figure 2 the structure shown. For example, it can 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 reaches one side edge of the first dielectric film 13, and the other metal layer reaches the other side edge of the first dielectric film 13. In this case, if it is arranged such that one metal layer in the first metal layer 15 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, the thin film of the present invention can be used as the dielectric film.

[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 showing the correspondence with Figure 5 a cross-sectional schematic diagram of a portion corresponding to the line segment B1 - B2 in

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

[0068] The thin 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. More specifically, the thin film 110 contains 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 multiple hydroxyl groups in the molecule.

[0071] Examples of the polyol include polyvinyl acetals such as polyvinyl acetal, polyether polyols such as phenoxy resins, and polyester polyols.

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

[0073] As the first organic material, multiple materials can also be used in combination.

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

[0075] The second organic material forms a crosslinked structure by reacting with the hydroxyl group of the first organic material, 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 having multiple isocyanate groups in the molecule among aromatic compounds.

[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, multiple materials can also be used in combination.

[0080] The thin film 110 is in Figure 2In the thin film capacitor 10 shown, it can be used for both the first dielectric thin film 13 and the second dielectric thin film 14, or for either the first dielectric thin film 13 or the second dielectric thin film 14. When the thin film 110 is used for Figure 2 both the first dielectric thin film 13 and the second dielectric thin film 14 of the thin film capacitor 10 shown, the compositions of the first dielectric thin film 13 and the second dielectric thin 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 a first organic material and a 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, there are a plurality of protrusions 120 on the first main surface 110a. In addition, there is a flat portion 130 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 a black-looking part 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, that is, aromatic isocyanate. More specifically, the aromatic isocyanate possessed by the protrusion 120 is derived from the aromatic isocyanate constituting the cured product contained 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 using the thin film 110 to manufacture a thin film capacitor, even when the thin film 110 is wound or pressed after winding, the protrusion 120 is not easily damaged, so 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, so the self-healing property of the thin film capacitor becomes excellent.

[0087] In contrast, when the protrusion 120 contains an aliphatic isocyanate, the hardness of the protrusion 120 is lower than that when the protrusion 120 contains an aromatic isocyanate. Therefore, when manufacturing a film capacitor using the film 110, if the 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 overlapping films 110. As a result, at the time of insulation breakdown, the decomposition gas from the film 110 is less likely to escape from the inside of the film capacitor, and thus the self-healing property of the film capacitor decreases.

[0088] In addition, even when the protrusion 120 contains an aromatic isocyanate, for example, if the skewness of the first main surface 110a of the film 110 described later is less than 0.782, when manufacturing a film capacitor by winding the film 110, it becomes difficult to form a gap between the overlapping films 110, and thus the self-healing property of the film capacitor also decreases.

[0089] The presence of the aromatic isocyanate in the protrusion can be confirmed as follows. First, using a Fourier transform infrared spectrometer (FT-IR) "FT / IR-4100ST" manufactured by JASCO Corporation, the measurement wave number range is set to 500 cm -1 or more and 4000 cm -1 or less, and 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 that the absorption peaks of the aromatic ring and the isocyanate group are detected, it can be confirmed that the protrusion contains an aromatic isocyanate. For example, when MDI is used as the aromatic isocyanate, in the infrared absorption spectrum, the absorption peak of the aromatic ring can be detected in the wave number range of 1450 cm -1 or more and 1550 cm -1 or less, and the absorption peak of the isocyanate group can be detected in the wave number range of 2200 cm -1 or more and 2400 cm -1 or less.

[0090] Furthermore, by the same method, in the infrared absorption spectrum of the flat portion, by confirming that the absorption peaks of the aromatic ring and the isocyanate group are detected, it can be confirmed that the aromatic isocyanate contained in the protrusion is derived from the aromatic isocyanate constituting the cured product contained in the film.

[0091] In the film of the present invention, in the area of 100 μm × 140 μm of the first main surface, the skewness of the first main surface is 0.782 or more and 14.3 or less.

[0092] In Figure 5 and Figure 6In the film 110 shown, within an area of 100 μm × 140 μm on the first major surface 110a, the skewness of the first major surface 110a is 0.782 or more and 14.3 or less.

[0093] The skewness of the surface of the film is also referred to as the surface height skewness Ssk (degree of deviation), and is an index indicating the symmetry of the height distribution of the surface of the film. The surface of the film exhibits the following forms according to the range of Ssk.

[0094] Ssk > 0: It shows that there are many small hills (protrusions) on the surface of the film.

[0095] Ssk = 0: It shows that the surface of the film is symmetric in the thickness direction.

[0096] Ssk < 0: It shows that there are many small valleys (recesses) on the surface of the film.

[0097] In the film 110, the smaller the height of the protrusion 120 or the fewer the number of protrusions 120, the lower the skewness of the first major surface 110a becomes. On the other hand, in the film 110, the larger the height of the protrusion 120 or the more the number of protrusions 120, the higher the skewness of the first major surface 110a becomes.

[0098] In order to improve the slidability when the films 110 slide against each other, it is important to reduce the contact area between the films 110. From this point of view, in the film 110, as described above, there are a plurality of protrusions 120 on the first major surface 110a, and it is desired to reduce the contact area between the films 110 when the films 110 slide against each other. However, depending on the skewness of the first major surface 110a of the film 110, it may not be possible to balance slidability and withstand voltage. In this regard, within the above-mentioned area of the first major surface 110a of the film 110, since the skewness of the first major surface 110a of the film 110 is 0.782 or more and 14.3 or less, the slidability and withstand voltage of the film 110 become excellent. Furthermore, since the slidability of the film 110 becomes excellent, when winding the film 110 to form a film capacitor, the pressability and self-healing properties are improved.

[0099] When the skewness of the first major surface 110a of the film 110 is less than 0.782, when the films 110 slide against each other, the contact area between the films 110 tends to become large, so the slidability decreases. When the skewness of the first major surface 110a of the film 110 is higher than 14.3, there are more parts where the electric field is likely to concentrate, such as the protrusion 120, so the withstand voltage decreases.

[0100] Within the above-mentioned area of the first main surface 110a of the film 110, as long as the skewness of the first main surface 110a of the film 110 is 0.782 or more and 14.3 or less, a plurality of concave portions may exist on the first main surface 110a of the film 110 in addition to the plurality of protrusions 120.

[0101] The skewness of the first main surface of the film can be determined as follows. First, using a laser microscope "VK-8700" manufactured by Keyence Corporation, the first main surface of the film is magnified 100 times, and an area range of 100 μm × 140 μm is observed. At this time, aluminum with a thickness of 10 nm can also be pre-evaporated on the first main surface of the film. Then, using the dedicated analysis software "VK-analyzer" of the laser microscope "VK-8700" manufactured by Keyence Corporation, the surface height skewness Ssk within the above-mentioned area range is measured, and the obtained measured value is determined as the skewness of the first main surface of the film.

[0102] The planar shape of the protrusion 120 can be Figure 5 the circular shape shown, the elliptical shape, or other shapes.

[0103] The planar shapes of the protrusions 120 can be the same as each other or different from each other.

[0104] The cross-sectional shape of the protrusion 120 can be Figure 6 the conical shape shown, or a shape other than the conical shape.

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

[0106] The top surface of the protrusion 120 is preferably Figure 6 depressed as shown. In this case, when the films 110 slide against each other, the contact area between the protrusions 120 becomes small, so the slidability is easily improved. In addition, the top surface of the protrusion 120 may not be depressed.

[0107] In addition, the protrusion 120 can be a shape with a sharp front end or a shape with a rounded front end.

[0108] There are no protrusions on the second main surface 110b of the film 110, but a plurality of protrusions may also exist. In this case, within the area range of 100 μm × 140 μm of the second main surface 110b of the film 110, the skewness of the second main surface 110b of the film 110 is preferably 0.782 or more and 14.3 or less. At this time, in addition to the plurality of protrusions, a plurality of concave portions may exist on the second main surface 110b of the film 110.

[0109] The skewness of the second major surface of the film can be determined in the same manner as the skewness of the first major surface of the film, except that the object to be observed is the second major surface of the film.

[0110] In the film of the present invention, it is preferable that the coefficient of static friction on the first major surface side is 1.0 or less.

[0111] In Figure 5 and Figure 6 In the film 110 shown, it is preferable that the coefficient of static friction on the first major surface 110a side is 1.0 or less. In this case, the slidability of the film 110 becomes extremely excellent.

[0112] On the other hand, if the coefficient of static friction of the film 110 on the first major 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 may be difficult to form an external electrode on the end face of the obtained wound body. From such a viewpoint, the coefficient of static friction of the film 110 on the first major surface 110a side is preferably 0.1 or more.

[0113] 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 major surfaces of each test specimen for measurement, during manufacturing, the major surface on the substrate side is defined as the release surface, and the major surface on the side opposite to the substrate is defined as the drying surface. More specifically, for each test specimen, the drying surface corresponds to the first major surface, and the release surface corresponds to the second major 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 manufacturing process 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.

[0114] In the film 110, it is preferable that the glass transition temperature is 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.

[0115] 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 are measured under the measurement conditions where the measurement frequency is set to 10 rad / s and the strain is set to 0.1%. Then, the temperature at which the loss tangent (tanδ) represented by loss modulus / storage modulus shows the maximum peak is determined as the glass transition temperature.

[0116] The thickness S of the thin film 110 is preferably 1 μm or more and 10 μm or less, and more preferably 3 μm or more and 5 μm or less.

[0117] As Figure 6 shown, the thickness S of the thin film is the thickness determined at a position where there are no protrusions 120.

[0118] Regarding the thickness of the thin film, it can be measured using an optical film thickness meter.

[0119] The thin film of the present invention becomes a metallized thin film by providing a metal layer on at least the first main surface, and can constitute the thin film capacitor of the present invention.

[0120] 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 showing the correspondence with Figure 7 the cross-sectional schematic diagram of the part corresponding to the line segment C1 - C2 in

[0121] As Figure 7 and Figure 8 shown, the metallized thin film 210 has Figure 5 and Figure 6 the thin film 110 shown, and a metal layer 220 provided on the first main surface 110a of the thin film 110.

[0122] In the thin film capacitor of the present invention, on the first main surface of the above dielectric thin film, there are a plurality of protrusions having the above second organic material.

[0123] In Figure 8 the thin film 110 shown, similar to the thin film 110 shown in Figure 5 and Figure 6 on the first main surface 110a, there are a plurality of protrusions 120 having a 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 there are no protrusions 120.

[0124] By having an aromatic isocyanate in the protrusion 120, it is possible to make the thin film capacitor of the metallized thin film 210 having the metal layer 220 provided on the first main surface 110a of the thin film 110 into a thin film capacitor with excellent self-healing properties.

[0125] In the first mode of the thin film capacitor of the present invention, within the area of 100 μm × 140 μm on the first main surface of the dielectric thin film, the skewness of the first main surface of the dielectric thin film is 0.782 or more and 14.3 or less. In this way, in the first mode of the thin film capacitor of the present invention, attention is paid to the skewness of the first main surface of the dielectric thin film where the plurality of protrusions exist.

[0126] In Figure 8 the shown thin film 110, similar to Figure 5 and Figure 6 the shown thin film 110, within the area of 100 μm × 140 μm on the first main surface 110a, the skewness of the first main surface 110a is 0.782 or more and 14.3 or less.

[0127] By the skewness of the first main surface 110a of the thin film 110 being 0.782 or more and 14.3 or less within the above area on the first main surface 110a of the thin film 110, the slidability and the withstand voltage property 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 the self-healing property are improved.

[0128] In a thin film capacitor, when measuring the skewness of the first main surface of the thin film, for the region where no metal layer is provided on the metallized thin film located on the outermost surface of the thin film capacitor, the measurement is performed by the above method. At this time, when a 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.

[0129] In the thin film capacitor of the present invention, as the metallized thin film, the metallized thin film of the present invention can be used.

[0130] The metallized film of the present invention includes: a film including 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 facing each other in the thickness direction; and a metal layer provided on at least the first main surface of the film. Further, 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.

[0131] 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.

[0132] In the first mode of the film capacitor of the present invention, when there are the plurality of convex portions on the surface of the metal layer provided on the first main surface of the dielectric film, similar to the second mode of the film capacitor of the present invention described later, it is preferable that in an area of 100 μm × 140 μm on the surface of the metal layer, the skewness of the surface of the metal layer is 0.562 or more and 13.9 or less.

[0133] In the second mode of the film capacitor of the present invention, 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.

[0134] In Figure 7 and Figure 8 In the metallized film 210 shown, on the surface 220a of the metal layer 220 on the side opposite to the first main surface 110a of the film 110, there are a plurality of convex portions 230 along the plurality of protrusions 120. Further, on the surface 220a of the metal layer 220, there is a flat portion 240 where there are no convex portions 230.

[0135] Regarding the presence of the convex portions, it can be confirmed as a black-looking part by observing the surface of the metal layer using a scanning electron microscope.

[0136] In the metallized film of the present invention, in an area of 100 μm × 140 μm on the surface of the metal layer, the skewness of the surface of the metal layer is 0.562 or more and 13.9 or less.

[0137] 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, the skewness of the surface of the metal layer is 0.562 or more and 13.9 or less. Thus, in the second mode of the thin film capacitor of the present invention, attention is paid to the skewness of the surface of the metal layer where the plurality of convex portions exist.

[0138] In Figure 7 and Figure 8 In the metallized film 210 shown, within an area of 100 μm × 140 μm on the surface 220a of the metal layer 220, the skewness of the surface 220a of the metal layer 220 is 0.562 or more and 13.9 or less.

[0139] By having the skewness of the surface 220a of the metal layer 220 within the above-mentioned area be 0.562 or more and 13.9 or less, the slidability and withstand voltage property of the metallized film 210 become excellent. Furthermore, since the slidability of the metallized film 210 becomes excellent, the pressability and self-healing property are improved when the metallized film 210 is wound to form a thin film capacitor.

[0140] When the skewness of the surface 220a of the metal layer 220 is less than 0.562, when the metallized films 210 slide against each other, the contact area between the metallized films 210 easily becomes large, so the slidability decreases. When the skewness of the surface 220a of the metal layer 220 is greater than 13.9, there are more portions where the electric field easily concentrates, such as the convex portion 230, so the withstand voltage property decreases.

[0141] Within the above-mentioned area of the surface 220a of the metal layer 220, as long as the skewness of the surface 220a of the metal layer 220 is 0.562 or more and 13.9 or less, there may be a plurality of concave portions on the surface 220a of the metal layer 220 in addition to the plurality of convex portions 230.

[0142] The skewness of the surface of the metal layer can be determined in the same manner as the skewness of the first major surface of the thin film, except that the observation object is the surface of the metal layer.

[0143] In a thin film capacitor, when measuring the skewness of the surface of the metal layer, the measurement is performed in a given area of the metallized film located on the outermost surface of the thin film capacitor.

[0144] In Figure 3In the winding body 40 shown, preferably in the region L of the second metallized film 12 located on the outermost surface, with the second metal layer 16 provided, the skewness of the surface of the second metal layer 16 is measured by the above method. Here, the region L of the second metallized film 12 is a square shape with a length of M in both the width direction W and the length direction (winding direction). Further, when defining the center line Q that passes through the center point P of the end edge N of the second metallized film 12 and extends in the length direction, the region L of the second metallized film 12 is line-symmetric in the width direction W with respect to the center line Q. The length M of the region L of the second metallized film 12 is 10% of the length of the end edge N of the second metallized film 12.

[0145] In the metallized film of the present invention, the coefficient of static friction on the surface side of the metal layer provided on the first main surface of the above-mentioned film is preferably 1.4 or less.

[0146] In the first mode of the 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 film, the coefficient of static friction on the surface side of the metal layer provided on the first main surface of the dielectric film is preferably 1.4 or less.

[0147] In the second mode of the film capacitor of the present invention, the coefficient of static friction on the surface side of the metal layer provided on the first main surface of the dielectric film is preferably 1.4 or less.

[0148] In Figure 7 and Figure 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.

[0149] 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, a winding deviation of the metallized film 210 occurs in the width direction, and in subsequent processes, it sometimes becomes difficult to form an external electrode on the end face of the obtained winding body. From this point of view, 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.

[0150] 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 test specimen for measurement.

[0151] As a constituent material of the metal layer 220, for example, metals such as aluminum, zinc, titanium, magnesium, tin, and nickel can be cited.

[0152] The thickness of the metal layer 220 is preferably 5 nm or more and 40 nm or less.

[0153] 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).

[0154] The thin film of the present invention can be manufactured, for example, by the following method.

[0155] <Production process of resin solution>

[0156] 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.

[0157] As the first organic material and the second organic material, the above-mentioned materials can be used.

[0158] 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.

[0159] Examples of the ketones for selecting the first solvent include methyl ethyl ketone, diethyl ketone, and the like.

[0160] As the first solvent, a plurality of ketones can also be used in combination.

[0161] Examples of the cyclic ether compounds for selecting the second solvent include tetrahydrofuran, tetrahydropyran, and the like.

[0162] As the second solvent, a plurality of cyclic ether compounds can also be used in combination.

[0163] As the solvent, a mixed solvent containing methyl ethyl ketone and tetrahydrofuran is preferably used.

[0164] <Drying / curing process of resin solution>

[0165] First, the resin solution is applied to the surface of a substrate.

[0166] Examples of the substrate include polyethylene terephthalate film, polypropylene film, and the like.

[0167] Next, after drying the coating film of the obtained resin solution with a drying furnace, it is cured by heat treatment. Thereby, a thin film is formed on the surface of the substrate.

[0168] 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, aggregates 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 aggregates. Further, the height, number, etc. of these protrusions are controlled. As a result, in the state of the thin film obtained by curing the coating film, within an area of 100 μm × 140 μm of the first main surface corresponding to the drying surface, the skewness of the first main surface can be controlled to be 0.782 or more and 14.3 or less.

[0169] The drying temperature of the coating film is preferably adjusted within the range of 70°C or more and 150°C or less.

[0170] The drying time of the coating film can be adjusted by the conveying speed of the substrate with the coating film on the conveyor belt in the drying furnace. The conveying speed is preferably adjusted within the range of 100 m / min or more and 160 m / min or less.

[0171] In addition, the obtained thin film is used in a state of being peeled off from the substrate. As described above, the first main surface of the thin film corresponds to the drying surface, which is the main surface on the side opposite to the substrate, in the coating film. Further, the second main surface of the thin film corresponds to the demolding surface, which is the main surface on the substrate side, in the coating film.

[0172] According to the above, make as Figure 5 and Figure 6 shown thin film.

[0173] The metallized thin film of the present invention can be manufactured, for example, by the following method.

[0174] <Manufacturing process of metallized thin film>

[0175] 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, make as Figure 5 and Figure 6 shown thin film.

[0176] Secondly, 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. Further, 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.

[0177] In addition, a second metallized film is fabricated by vapor-depositing a metal on the first major surface of the second dielectric film to form a second metal layer. At this time, the second metal layer is formed such that multiple convex portions are present on the surface of the second metal layer on the side opposite to the first major surface of the second dielectric film along multiple protrusions of the second dielectric film. Further, the second metal layer is formed such that in the width direction, it does not reach one side edge of the second dielectric film but reaches the other side edge of the second dielectric film.

[0178] Through this process, the first metallized film and the second metallized film are fabricated as the metallized films shown in Figure 7 and Figure 8 .

[0179] The thin film capacitor of the present invention can be manufactured, for example, by the following method.

[0180] <Manufacturing process of the wound body>

[0181] First, by the manufacturing method of the metallized film of the present invention described above, the first metallized film and the second metallized film are fabricated as the metallized films shown in Figure 7 and Figure 8 .

[0182] Next, the first metallized film and the second metallized film are overlapped in a state where they are offset by a given distance in the width direction and then wound to fabricate a wound body. Additionally, if necessary, the obtained wound body can be pressed into an elliptical cylindrical shape by clamping it from the direction perpendicular to the width direction.

[0183] <Forming process of the external electrode>

[0184] The first external electrode is formed by spraying a metal on one end face of the wound body so as to be connected to the first metal layer.

[0185] In addition, the second external electrode is formed by spraying a metal on the other end face of the wound body so as to be connected to the second metal layer.

[0186] According to the above, the thin film capacitors shown in Figure 1 and Figure 2 are manufactured.

[0187] The thin film capacitor of the present invention can be applied to known uses, but since it can achieve a longer lifespan for devices used in environments with large temperature changes at high temperatures, it is suitable for power electronic devices such as electric compressors / pumps, chargers, DC-DC converters, and drive inverters mounted in automobiles, industrial equipment, etc.

[0188] [Embodiment]

[0189] Hereinafter, embodiments of the thin film capacitor, the thin film, and the metallized thin film of the present invention are more specifically disclosed. In addition, the present invention is not limited to these embodiments.

[0190] Thin film specimens 1 to 5 were manufactured by the following method.

[0191] <Production process of resin solution>

[0192] A resin solution was prepared by diluting and mixing a phenoxy resin and MDI with a mixed solvent of methyl ethyl ketone and tetrahydrofuran.

[0193] <Drying / curing process of resin solution>

[0194] First, the resin solution was applied to the surface of a polyethylene terephthalate film using a gravure coater.

[0195] Next, 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 5 with a thickness of 4.5 μm were produced on the surface of the polyethylene terephthalate film.

[0196] At this time, for the coating film of the resin solution, by adjusting the drying temperature in the range of 70°C or higher and 150°C or lower, and in addition, adjusting the conveying speed in the drying furnace in the range of 100 m / min or higher and 160 m / min or lower, the generation condition of protrusions having MDI was controlled on the first main surface of the thin film specimen. Further, the height, number, etc. of the protrusions were controlled. As a result, the skewness of the first main surface of the thin film specimens differed among thin film specimens 1 to 5.

[0197] Then, the obtained thin film specimens 1 to 5 were peeled off from the polyethylene terephthalate film.

[0198] In addition, in the resin solution used for manufacturing thin film specimens 1 to 5, hexamethylene diisocyanate (HDI) as an aliphatic polyisocyanate was used in place of MDI, and thin film specimen 6 was manufactured by the same method as thin film specimens 1 to 5.

[0199] In addition, a thin film specimen 7 having no protrusions on the first main surface was manufactured using the same resin solution as that used for manufacturing thin film specimens 1 to 5. Further, a filler was further added to the resin solution used for manufacturing thin film specimen 7, and the mixing ratio of the filler was changed, thereby manufacturing thin film specimens 8 to 10. Regarding the mixing ratio of the filler, it was set to 1% by weight in thin film specimen 8, 3% by weight in thin film specimen 9, and 10% by weight in thin film specimen 10 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.

[0200] [Evaluation]

[0201] Regarding thin film specimens 1 to 5, it was confirmed by the above method that the protrusions had MDI. Regarding thin film specimen 6, it was confirmed that the protrusions had HDI. Regarding thin film specimen 7, it was confirmed that there were no protrusions on the first major surface. Regarding thin film specimens 8 to 10, it was confirmed that the first major surface was rough due to the filler.

[0202] Furthermore, regarding thin film specimens 1 to 10, the following evaluations were carried out. The results are shown in Table 1. In addition, in Table 1, the thin film specimens are simply recorded as "specimens".

[0203] <Skewness 1>

[0204] Regarding thin film specimens 1 to 10, the skewness of the first major surface of the thin film specimens was measured by the above method. In addition, in Table 1, the skewness in the state of the thin film is recorded as "Skewness 1".

[0205] <Skewness 2>

[0206] A metal layer was formed by vapor-depositing aluminum on the first major surface of thin film specimens 1 to 10 to fabricate metallized thin films. Then, regarding the obtained metallized thin films, the skewness of the surface of the metal layer was measured by the above method. In addition, in Table 1, the skewness in the state of the metallized thin film is recorded as "Skewness 2".

[0207] <Glass transition temperature>

[0208] Regarding thin film specimens 1 to 6, the glass transition temperature was measured by the above method.

[0209] <Coefficient of static friction 1>

[0210] Regarding thin film specimens 1 to 10, 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 is recorded as "Coefficient of static friction 1".

[0211] <Coefficient of static friction 2>

[0212] A metal layer was formed by vapor-depositing aluminum on the first major surface of thin film specimens 1 to 10 to fabricate metallized thin films. Then, regarding the obtained metallized thin films, 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 is recorded as "Coefficient of static friction 2".

[0213] <Insulation breakdown voltage>

[0214] First, a measurement specimen was fabricated by depositing aluminum on both major surfaces of film specimens 1 to 10 to form a metal layer. At this time, the area of the region where the metal layers deposited on both major surfaces of the film specimen overlapped each other was set to 3 cm 2 . For each of the film specimens 1 to 10, 16 such measurement specimens were fabricated. Next, for the 16 measurement specimens, each electric field strength was maintained for 10 minutes at a scale of 25 V / μm, and the electric field strength when 8 breakdown marks occurred in the film specimen was set as the failure voltage. Regarding the measurement temperature, it was set to 125°C. Then, Weibull plotting was performed on the failure voltages of the 16 measurement specimens, and the value at which the failure frequency became 50% in this Weibull distribution was adopted as the insulation breakdown voltage of the film specimen.

[0215] <Suppressive property>

[0216] First, a metallized film was fabricated by depositing aluminum on the first major surface of film specimens 1 to 10 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 major surface of the film specimen. Next, 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, while appropriately adjusting the pressing force in the range of 10 N or more and 100 N or less, the wound body was pressed, and then whether the wound body was uniformly pressed was evaluated. 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 gap 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 gap portion at the center of the winding had wrinkles / fractures was set as × (bad).

[0217] <Self-healing property>

[0218] First, a metallized film was fabricated by depositing aluminum on the first major surface of film specimens 1 to 10 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 major surface of the film specimen. Next, 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 thin film capacitor. Then, while applying a voltage to the obtained thin film capacitor, the applied voltage was gradually increased, and it was evaluated whether it recovered 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 recovered to the original applied voltage was set as ○ (good), and the case where it did not recover to the original applied voltage was set as × (bad).

[0219] [Table 1]

[0220]

[0221] In Table 1, the specimens with * in the specimen name are comparative examples outside the scope of the present invention.

[0222] 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 the skewness of the first main surface is 0.782 or more and 14.3 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 thin film, it was confirmed that the skewness of the surface of the metal layer is 0.562 or more and 13.9 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 static friction coefficient 1 and static friction coefficient 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 more, and the heat resistance is also excellent.

[0223] In thin film specimen 4, it was confirmed that almost no protrusions exist on the first main surface, and the skewness of the first main surface is less than 0.782. 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 thin film, it was confirmed that almost no convex portions exist on the surface of the metal layer, and the skewness of the surface of the metal layer is less than 0.562. From such thin film specimen 4, compared with thin film specimens 1 to 3, static friction coefficient 1 and static friction coefficient 2 become higher, and the pressability and self-healing properties of the thin film capacitor cannot be made excellent.

[0224] In thin film specimen 5, it was confirmed that a very large number of protrusions exist on the first main surface, and the skewness of the first main surface is higher than 14.3. 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 thin film, it was confirmed that a very large number of convex portions exist on the surface of the metal layer, and the skewness of the surface of the metal layer is higher than 13.9. From such thin film specimen 5, compared with thin film specimens 1 to 3, the insulation breakdown voltage becomes lower.

[0225] In thin film specimen 6, the protrusions have aliphatic isocyanate, so the self-healing property of the thin film capacitor cannot be made excellent.

[0226] In the thin film sample 7, there are no protrusions. Further, in a state where a metal layer is vapor-deposited on the first main surface of the thin film sample 7 to form a metallized thin film, there are no convex portions. Therefore, based on the thin film sample 7, as compared with the thin film samples 1 to 3, the static friction coefficient 1 and the static friction coefficient 2 are higher, and the pressability and self-healing property of the thin film capacitor cannot be made excellent. Further, in the thin film sample 7, the first main surface is gently recessed as a whole, and thus the skewness of the first main surface is a negative value. Further, in a state where a metal layer is vapor-deposited on the first main surface of the thin film sample 7 to form a metallized thin film, the surface of the metal layer is gently recessed as a whole, and thus the skewness of the surface of the metal layer is a negative value.

[0227] In the thin film samples 8 to 10, a filler is incorporated, and thus, as compared with the thin film samples 1 to 3, the dielectric breakdown voltage is low. Further, based on the thin film sample 8, as compared with the thin film samples 1 to 3, the static friction coefficient 1 and the static friction coefficient 2 are higher, and the pressability and self-healing property of the thin film capacitor cannot be made excellent.

[0228] Description of reference numerals

[0229] 10 Thin film capacitor;

[0230] 11 First metallized thin film;

[0231] 12 Second metallized thin film;

[0232] 13 First dielectric thin film;

[0233] 13a First main surface of the first dielectric thin film;

[0234] 13b Second main surface of the first dielectric thin film;

[0235] 14 Second dielectric thin film;

[0236] 14a First main surface of the second dielectric thin film;

[0237] 14b Second main surface of the second dielectric thin film;

[0238] 15 First metal layer;

[0239] 16 Second metal layer;

[0240] 40 Winding body;

[0241] 41 First external electrode;

[0242] 42 Second external electrode;

[0243] 61 Divided electrode portion;

[0244] 62 Electrode portion;

[0245] 63 Fuse part;

[0246] 64 Insulating slit;

[0247] 110 Thin film (dielectric thin film);

[0248] 110a First main surface of the thin film;

[0249] 110b Second main surface of the thin film;

[0250] 120 Protrusion of the thin film;

[0251] 130 Flat part of the thin film;

[0252] 210 Metallized thin film;

[0253] 220 Metal layer;

[0254] 220a Surface of the metal layer;

[0255] 230 Convex part of the metal layer;

[0256] 240 Flat part of the metal layer;

[0257] L Region of the second metallized thin film;

[0258] M Length of the region of the second metallized thin film;

[0259] N Edge of the second metallized thin film;

[0260] P Center point of the edge of the second metallized thin film;

[0261] Q Center line;

[0262] S Thickness of the thin film;

[0263] T Laminating direction;

[0264] W Width direction.

Claims

1. A thin film capacitor, characterized in that it has 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 opposed to 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, the skewness of the first main surface of the dielectric film is 0.782 or more and 14.3 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 on the surface side of the metal layer provided on the first main surface of the dielectric film 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 axis direction, the cross-sectional shape of the wound body is a flat shape.

5. A thin film capacitor, characterized in that it has 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 opposed to 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. In the area of 100 μm × 140 μm on the surface of the metal layer, the skewness of the surface of the metal layer is 0.562 or more and 13.9 or less.

6. The thin film capacitor according to claim 5, characterized in that the static friction coefficient 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, characterized in that when observing the 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 for a thin film capacitor, 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 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 the area of 100 μm × 140 μm on the first major surface, the skewness of the first major surface is 0.782 or more and 14.3 or less.

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

10. A metallized film, characterized in that, Comprising: A thin film, comprising 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 major surface and a second major surface opposed to each other in the thickness direction; And A metal layer provided on at least the first major surface of the thin film, On the first major 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 major surface of the thin film, on the side opposite to the first major 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, the skewness of the surface of the metal layer is 0.562 or more and 13.9 or less.

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

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