JP2000208358A - Film for capacitor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form a dielectric layer having a uniform thickness by adding dimethylol tricyclo-decan diacrylate and 2-ethylhexyl acrylate expressed by specific formulae to dielectric paint at a specific weight ratio. SOLUTION: A metallic thin film layer 3 composed mainly of aluminum is formed on at least one surface of a high polymer film 1. On at least one surface of this metallized film, a dielectric layer 2 having a uniform thickness is formed by applying dielectric paint containing dimethylol tricyclo-decan diacrylate expressed by formula I and 2-ethylhexyl acrylate expressed by formula II at a weight ratio between 80:20 and 95:5 to the surface. The dielectric paint is composed mainly of the acrylic ester resins and contains a photopolymerization initiator for accelerating a polymerization reaction when the resins are irradiated with ultraviolet rays.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dielectric used for a film capacitor as one of electronic components.

[0002]

2. Description of the Related Art A conventional film capacitor using a coating type metallized film is disclosed in Japanese Patent Laid-Open No. 55-5851 as an example. FIG. 2 shows a conventionally used coating type metallized film. A metal thin film mainly composed of aluminum is formed on both surfaces of a polymer film 1 shown in FIG. 3 by a vacuum deposition method or an ion plating method. Using a metallized film 13 having a layer 3 and margins 4 and 5 without a metal thin film layer, a dielectric paint in which polycarbonate, polyphenylene oxide or polyarylate is dissolved in an organic solvent is applied on both sides or one side of the metallized film in FIG. It is applied so that the dielectric layer 9 as shown is formed. Here, reference numeral 10 denotes a margin portion where the dielectric paint formed simultaneously with the application of the dielectric layer is not applied, and reference numeral 11 denotes a margin portion in the case of double-side application. Thereafter, the organic solvent contained as a diluent in the dielectric coating is evaporated and dried to obtain a coating type metallized film 12. As the organic solvent used here, at least one selected from dichloromethane, dichloroethane, trichloroethylene and the like is used. It has been conventionally proposed to use a UV-curable resin as a dielectric paint for forming a dielectric film to form a coating-type metallized film 18 as shown in FIG. The dielectric paint coating type metallized film 18 is formed by applying an ultraviolet curable resin on at least one surface of the metallized film 13 so as to form a dielectric layer 14 as shown in FIG. It is obtained by curing the UV-curable paint to form the dielectric layer 14. Here, reference numeral 15 denotes a margin portion formed simultaneously with the application of the ultraviolet curable resin, and reference numeral 16 denotes a margin in the case of double-side coating. The dielectric paint constituting the dielectric layer 14 is obtained by adding a photopolymerization initiator that causes a curing reaction of the ultraviolet-curable resin to an ultraviolet-curable resin,
Solvent-free coating is possible.

[0003]

However, in a conventional coating type film capacitor, a polymer compound used for a dielectric is dissolved in an organic solvent, and the resultant is applied to form a dielectric layer. In the method, a polymer compound cannot be dissolved unless an organic solvent is used, and a heat source for evaporating and removing the organic solvent and a cooling device or a high-performance solvent recovery device are required. Further, the present inventors, in order to create a coating type capacitor film in which the dielectric layer is made of an acrylate resin,
As shown in FIG. 3, the thickness of the dielectric layer without solvent is applied to the surface of the metallized film 13 in which a metal thin film layer containing aluminum as a main component is formed on the surface of a polymer film by a vacuum evaporation method or an ion plating method. In order to form a thin film having a thickness of 1.5 μm, a dielectric coating material 20 is weighed and adhered to the surface of a gravure roll 19 having gravure engraving as shown in FIG. When trying to coat by contacting the surface while rotating the metallized film in the opposite direction, the dimethylol tricyclodecane, an ultraviolet-curable resin selected to obtain the required dielectric loss angle characteristics, was used. Since acrylate has a high viscosity, an ultraviolet ray is applied between the metallized film 13 and the gravure roll 19. As a result a uniform thickness of the dielectric layer was found to not be formed of resin is not leveled sufficiently. The capacitor manufactured using such a film has a problem that the withstand voltage level and the capacitance accuracy are deteriorated. Further, in order to secure the dielectric loss angle characteristic, no material other than dimethylol tricyclodecane diacrylate was found.

[0004]

In order to solve the above-mentioned problems, a low viscosity 2-ethylhexyl acrylate is added to dimethylol tricyclodecane diacrylate as a component of a dielectric coating material at a weight ratio of 80:20 to 95: 5. If it is added in such a range, the dielectric loss angle characteristic is not impaired, the viscosity can be reduced to an optimum for coating, and a dielectric layer having a uniform thickness can be formed.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention relates to a metallized film in which a metal thin film layer containing aluminum as a main component is formed on at least one surface of a polymer film by a vacuum evaporation method or an ion plating method. And a dielectric paint mainly composed of an acrylate resin having a weight ratio of dimethylol tricyclodecane diacrylate (Chem. 3) to 2-ethylhexyl acrylate (Chem. 4) in the range of 80:20 to 95: 5. This is a film for a capacitor formed by coating a dielectric layer having a uniform thickness by obtaining the optimum viscosity of a dielectric paint for coating without deteriorating the dielectric loss angle characteristics.

[0006]

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[0007]

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An embodiment of the present invention will be described below. (Embodiment 1) FIG. 3 is a cross-sectional view of a metallized film manufactured by a vacuum evaporation method for use in the present invention. In FIG. 3, a metallized film 13 is a polymer film made of polyethylene terephthalate (hereinafter, PET). 1, a metal thin film layer 3 mainly composed of aluminum (Al) on both surfaces and a margin 4 having no metal thin film layer
And 5. FIG. 1 is a sectional view of a coating type metallized film 7 of the present invention. FIG.
The coating type metallized film 7 has a dielectric layer 2 obtained by curing a dielectric paint mainly composed of an acrylate resin on one surface of the metallized film 13 by ultraviolet irradiation, and a margin 4 having no dielectric layer 2.
And 5. As the metallized film according to the present invention, a film obtained by vapor-depositing aluminum on a surface of polyethylene terephthalate (hereinafter abbreviated as PET) having a thickness of 1.5 μm by a vacuum deposition method so as to have a thickness of 350 Å was used. The dielectric coating material is mainly composed of an acrylate resin having a weight ratio of dimethylol tricyclodecane diacrylate (Chem. 5) to 2-ethylhexyl acrylate (Chem. 6) of 90 to 10, and a polymerization reaction at the time of ultraviolet irradiation. Product name, Irgacure 9 manufactured by Nippon Ciba Geigy Co., Ltd.
07 to 100 parts by weight of the acrylate resin
What was added by weight and stirred at room temperature for about 30 minutes was used.

[0009]

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[0010]

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In the coating method, the metallized film 13 is run at a speed of 50 m / min with a structure as shown in FIG.
The mesh of the gravure roll is a pyramid shape of 300 meshes, and is rotated at 400 revolutions per minute while rotating in the direction opposite to the traveling direction of the metallized film 13 and brought into contact with the metallized film 13. A body paint was applied, filled with nitrogen gas, and irradiated with an ultraviolet ray in an ultraviolet ray irradiation furnace having an oxygen concentration of 900 ppm or less and cured to obtain a coating type metallized film 7. The average thickness of the dielectric layer of the coating type metallized film 7 thus obtained was 1.5 μm, and the range of the thickness variation was 1.
4 to 1.6 μm. The film capacitor manufactured using this coating type metallized film (FIG. 6) has a variation in capacitance of ± 3% and a dielectric loss angle (tan δ) at a frequency of 1 kHz of 0.5.
０．６0.6%, the self-healing onset voltage in the dielectric breakdown test was 160 V on average. For comparison, the weight ratio of dimethylol tricyclodecane diacrylate to 2-ethylhexyl acrylate was 98: 2 and 75:25,
Other conditions were evaluated for the coating type metallized film produced under the same conditions as in the embodiment of the present invention. As a result, the weight ratio of dimethylol tricyclodecane diacrylate to 2ethylhexyl acrylate was 98%.
The average thickness of the dielectric layers of the pair 2 was 1.0 μm, and the variation range of the thickness was 0.5 to 1.6 μm. or,
A film capacitor manufactured using this coating type metallized film has a capacitance variation of ± 8% and a dielectric loss angle (tan) at a frequency of 1 kHz.
δ) was 0.5 to 0.55%, and the self-recovery starting voltage in the dielectric breakdown test was 30 V on average. When the weight ratio of dimethylol tricyclodecane diacrylate to 2-ethylhexyl acrylate was 75:25, the average thickness of the dielectric layer was 1.5 μm, and the variation range of the thickness was 1.4 to 1.6 μm. The film capacitor manufactured using this coating type metallized film has a variation in capacitance of ± 3% and a dielectric loss angle (tan δ) at a frequency of 1 kHz of 0.65 to 0.7.
%, Self-recovery starting voltage by dielectric breakdown test is 150 on average
V. As described above, as a result of examining the weight ratio of dimethylol tricyclodecane diacrylate and 2ethylhexyl acrylate, the weight ratio of dimethylol tricyclodecane diacrylate and 2 ethylhexyl acrylate was set to the range of 80:20 to 95: 5. By doing so, it was confirmed that a film for a capacitor which can obtain capacitor characteristics having no practical problem can be produced.

[0012]

As described above, when the weight ratio of dimethylol tricyclodecane diacrylate to 2-ethylhexyl acrylate is in the range of 80:20 to 95: 5, deterioration of the dielectric loss angle (tan δ) is minimized. Thus, a film for a capacitor can be obtained in which a dielectric layer having good withstand voltage characteristics and a good withstand voltage characteristic with a small variation in the thickness of the dielectric layer is ensured.

In the description of the embodiment of the present invention, the coating is applied to one surface, but the present invention is not limited to this. Although specific materials and numerical values have been described, they explain the details of the present invention, and the present invention is not limited thereto. Further, regarding the composition of the dielectric paint, additives such as an adhesive and a leveling agent may be added as necessary.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a coating type metallized film of the present invention.

FIG. 2 is a cross-sectional view of a conventional coating type metallized film.

FIG. 3 is a sectional view of a metallized film.

FIG. 4 is a cross-sectional view of a coating type metallized film using a conventional ultraviolet curable resin as a dielectric paint.

FIG. 5 is a diagram showing a coating method for producing a product of the present invention.

FIG. 6 is a view showing a film capacitor manufactured using the coating type metallized film of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Polymer film 2 Dielectric layer which consists of ultraviolet curing resin of this invention 3 Metal thin film layer 7 Coating type metallized film of this invention

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Minoyasu Aoto 1006 Kadoma Kadoma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. F-term (reference) 4F100 AB10B AB33B AK01A AK25C AK42A AL05C BA03 BA07 BA10B BA10C CC00C EH66B GB41 JG03 JG05C 4J038 CG141 CH041 CH051 CH071 NA17 5E082 BC09 BC30 BC35 EE08 EE24 FG37 PG06

Claims (1)

[Claims] 1. A metallized film in which a metal thin film layer containing aluminum as a main component is formed on at least one surface of a polymer film by a vacuum deposition method, an ion plating method, or the like. The weight ratio of decane diacrylate (Chem. 1) to 2-ethylhexyl acrylate (Chem. 2) is 80: 20-95.
A coating type metallized film for a capacitor, characterized in that a dielectric layer composed mainly of an acrylate resin composed in a range of 5 is applied to form a dielectric layer. Embedded image Embedded image