JPH10172862A - Film capacitor - Google Patents

Abstract

(57) [Summary] (Problem corrected) [PROBLEMS] To obtain a film capacitor excellent in moisture resistance by suppressing corrosion of a metal thin film layer by using a metallized film having a thick oxide layer of a metal thin film layer on one side or both sides. . SOLUTION: A single-sided or double-sided deposited film obtained by a vacuum deposition method, an ion plating method or the like is immersed in water and then dried, so that aluminum (Al) formed on the polymer film is mainly used. By increasing the thickness of the aluminum (Al) oxide layer 18 near the interface between the surface of the metal thin film layer 14 and the polymer film 17 in particular, corrosion of the metal thin film layer is suppressed, and the moisture resistance of the film capacitor is improved. .

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a film capacitor which is one of electronic components.

[0002]

2. Description of the Related Art Conventionally, a metallized film used for a film capacitor is disclosed in, for example, JP-A-3-2418.
08. FIG. 3 shows a conventionally used metallized film. As shown in FIG. 3, a metal mainly composed of aluminum (Al) is formed on both surfaces of a polymer film 17 by a vacuum deposition method, an ion plating method, or the like. The mark which is a portion without the thin film layer 14 and the metal thin film layer
The metallized film 2 on which gins 15 and 16 are formed is used. Aluminum (Al) formed on the conventionally used metallized film 2
The metal thin film layer 14 mainly composed of a metal oxide layer 19 has an oxide layer of only the metal oxide layer 19 on the surface by natural oxidation in the air.

[0003]

However, the use conditions of the film capacitor have become stricter, and the demand for improved reliability has become stronger. A conventionally proposed metallized film having a metal thin film layer mainly composed of aluminum (Al) has a thickness of a metal oxide layer formed by natural oxidation formed on the metal thin film layer. Is insufficient for improving the moisture resistance of the aluminum (A)
l) takes in water like a hydrate (Al2O3.6H2O), hastening the corrosion of aluminum (Al), causing the thin metal layer to disappear, and deteriorating properties such as a decrease in capacitance. Was.

[0004]

SUMMARY OF THE INVENTION In order to solve the above problems, the present invention provides a method for immersing a metallized film having a metal thin film layer mainly composed of aluminum (Al) in water,
A water-treated metallized film obtained by drying and thickening an aluminum (Al) oxide layer on the surface of a metal thin film layer or an interface portion with a polymer film as compared with a conventional metallized film is used for a film capacitor.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION The invention described in claim 1 of the present invention is characterized in that at least one surface of a polymer film is made of aluminum (A) by a vacuum deposition method, an ion plating method or the like.
1) After forming a metal thin film layer mainly containing the metal thin film layer, the metallized film is immersed in water and then dried to form a surface of aluminum (Al) forming the metal thin film layer or an interface portion with a polymer film. This is a film capacitor having improved moisture resistance by using a water-treated metallized film having a thick oxide layer.

According to a second aspect of the present invention, the polymer film is made of polypropylene (PP) or polyethylene terephthalate.
(PET), polyethylene naphthalate (PEN),
It is characterized by being polyphenylene sulfide (PPS). By using these polymer films, it is possible to obtain a film capacitor which satisfies various characteristics of the capacitor and has excellent moisture resistance. .

An embodiment of the present invention will be described below with reference to FIGS. FIG. 3 is a cross-sectional view of a metallized film manufactured by a vacuum deposition method. In FIG. 3, the metallized film 2 is made of a polymer film 17 made of polyethylene terephthalate (hereinafter referred to as PET) with aluminum (Al) on both surfaces. It is composed of a metal thin film layer 14 of aluminum (Al) covered with an oxide layer 19 formed by natural oxidation, which is a main component, and margins 15 and 16 which are portions without the metal thin film layer 14.

FIG. 1 shows a water treatment method for obtaining a water treatment metallized film 12 for producing a film capacitor of the present invention. The metallized film 2 manufactured by the vacuum evaporation method shown in FIG. 3 is unwound from the unwinding shaft 1 and passes through the free roll 3 to the tank 6 between the free rolls 4 and 5 provided in the tank 6. It is immersed in the stored water 7. Then metallized film 8 immersed in water
Enters an oven 11 through a free roll 9 and removes moisture on the surface of the metallized film by air 10 heated to 80 ° C. to form an oxide layer thicker than the metal oxide layer of the conventional metallized film. To obtain a water-treated metallized film 12 having the following. The arrow shown in the figure indicates the running direction of the metallized film.

FIG. 2 is a cross-sectional view of the water-treated metallized film 12 obtained by the water treatment of FIG. The water-treated metallized film 12 comprises a metal thin film layer 14 mainly composed of aluminum (Al) and margins 15 and 16 on both sides of a PET film. Due to the water treatment effect of the metal thin film layer 14 in the water treated metallized film 12, a metal oxide layer 18 thicker than a conventional metal thin film layer mainly containing aluminum (Al) is provided.

FIGS. 5 and 6 show X-ray photoelectron spectroscopy (ESCA) of a conventional metallized film and a water-treated metallized film used for the film capacitor of the present invention.
Are compared and shown. X-ray photoelectron spectroscopy (ESCA) can measure the atomic concentration for each element in the depth direction of the sample, and the polymer film portion has a depth where the carbon (C) concentration in the profile becomes a certain concentration or more. It can be seen that in the conventional metallized film of FIG. 5, a large amount of oxygen is detected at a depth of 0 to 8 (nm) and 40 to 55 (nm) from the surface. Aluminum (Al) metal has a depth of 8 (nm) to 40 (nm).
The atomic concentration is high between and is spared. On the other hand, in the water-treated metallized film shown in FIG.
-9 (nm) and 38-57 (nm), a large amount of oxygen is detected, and aluminum (Al) metal has a depth of 9 (nm) -3.
It can be seen that the atomic concentration is high between 8 (nm) and conserved. Further, as for the oxygen concentration, it can be seen that the peak value is higher in the water-treated metallized film of FIG. 6 than in the conventional metallized film of FIG. 5, and more oxygen is detected than in the conventional metallized film. From these facts, it is recognized that the metal oxide layer at the surface of the aluminum (Al) metal thin film layer of the water-treated metallized film and at the interface with the polymer film is thick. FIG.
In FIG. 6, the vertical axis represents the atomic concentration (%), and the horizontal axis represents the depth (nm) from the surface of the metal thin film layer.

FIGS. 4A and 4B show an example of a film capacitor manufactured using a water-treated metallized film. A polymer film without a metal thin film layer is alternately laminated with a water-treated metallized film as a laminated film 26 to obtain a laminated film capacitor laminate. Metallicons 20, 21 serving as external lead electrodes are formed by spraying on both ends of the element body, and then lead wires 22, 2 are formed.
After obtaining the laminated film capacitor element by providing No. 3, a required exterior processing was performed to produce a film capacitor. FIG.
FIG. 4A is a structural cross-sectional view of a multilayer film capacitor element, and FIG. 4B is a schematic view of a laminate.

The film capacitor of the present invention manufactured using the water-treated metallized film and the film capacitor manufactured by using the conventional metallized film in this manner were heated at a temperature of 60 ° C., a humidity of 95%, and an applied voltage of the film 1 ( FIG. 7 shows the results of a humidity resistance life test performed under the condition of 49 (v) per μm).

In FIG. 7, a is an example of a film capacitor of the present invention produced using a double-sided vapor-deposited, water-treated metallized film, b is an example of a film capacitor of the present invention produced using a double-sided vapor-deposited, water-treated metallized film, c
Is an example of a film capacitor manufactured using a conventional metallized film.

As is clear from FIG. 7, the change in capacitance of the film capacitor of the present invention manufactured using the water-treated metallized film is smaller even with a longer elapsed time than that of the conventional film capacitor using the metallized film.
It is recognized that the moisture resistance is improved.

[0015]

As described above, the film capacitor of the present invention using the water-treated metallized film in which the vaporized metallized film is immersed in water and dried to thicken the oxidized layer of the metal thin film layer, the corrosion of the metal thin film layer is suppressed. Thus, a capacitor having excellent moisture resistance can be obtained. Further, the present invention can be manufactured by a simple method, and therefore has high industrial value and can provide a high humidity resistant film capacitor at low cost.

In the description of the embodiment of the present invention, the water treatment is immersed in water. However, the present invention is not limited to this. The same effect can be obtained by spraying or adhering water in a high-humidity atmosphere. It is clear that the higher the water temperature, the faster the reaction rate and the more efficient the production.
Although specific materials and numerical values have been described, they are for explaining the details of the present invention, and the present invention is not limited thereto.

[Brief description of the drawings]

FIG. 1 is a diagram showing a process for obtaining a water-treated metallized film used in the present invention.

FIG. 2 is a cross-sectional view of a water-treated metallized film.

FIG. 3 is a cross-sectional view of a conventional metallized film.

FIG. 4A is a structural cross-sectional view of the multilayer film capacitor element of the present invention, and FIG.

FIG. 5 is a diagram showing a depth profile of a conventional metallized film by X-ray photoelectron spectroscopy.

FIG. 6 is a diagram showing a depth profile of a water-treated metallized film by X-ray photoelectron spectroscopy.

FIG. 7 is a diagram showing the results of a moisture resistance life test of the film capacitor of the present invention and the conventional film capacitor.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Unwinding shaft 2 Conventional metallized film 3, 4, 5, 9 Free roll 6 Tank 7 Water 8 Metallized film 10 Air 11 Drying furnace 12 Water treatment metallized film 13 Winding shaft 14 Metal thin film layer 15, 16 Margin 17 Polymer film Reference Signs List 18 metal oxide layer 19 metal oxide layer 20, 21 metallikon 22, 23 lead wire 24, 25 reinforcing layer 26 polymer film not forming metal thin film layer (laminated film)

Claims (2)

[Claims] 1. A film capacitor using a polymer film as a dielectric material, wherein aluminum (Al) serving as an internal electrode is used as a main component on one or both sides of the polymer film by a vacuum deposition method, an ion plating method or the like. A film capacitor using a metallized film having a metal thin film layer formed thereon, wherein the metallized film is immersed in water, and then a water-treated metallized film is used. 2. The polymer film is made of polypropylene (P
2. The film capacitor according to claim 1, wherein the film capacitor is made of P), polyethylene terephthalate (PET), polyethylene naphthalate (PEN), or polyphenylene sulfide (PPS).