JP2000216043A - Film for capacitor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance the productivity of a film for capacitor and to raise the capacitor characteristics of the film by a method wherein the polymerization degree of a dielectric material formed by coating a dielectric paint containing an ultraviolet cured rasin, which is constituted of a dimethyloltricyclodecanediacrylate and a 2- ethylhexylacrylate, as its main component on the surface of at least one side of the surfaces of a metallized film is specified. SOLUTION: A metallized film is formed by forming a metal thin film layer containing aluminium as its main component on the surface on at least one side of the surfaces of a high-molecular film by a vacuum evaporation method, an ion plating method or the like and the reduction rate of the C=C double bond of a dielectric material formed by coating a dielectric paint containing an ultraviolet cured resin constituted of dimethyloltricyclodecanediacrylate, which is shown by the formula 1, and a 2-ethylhexylacrylate, which is shown by the formula 2, as its main component on the surface on at least one side of the surfaces of the metallized film is reduced higher than 70%. Moreover, as the dielectric paint, a dielectric paint being included in the range of the weight ratio of a dielectric paint to a photopolymerization starting agent, which is shown by the formula 3, =100 to 1 to 100 to 5 is formed by coating.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[0002]

2. Description of the Related Art A conventional film capacitor using a capacitor film is disclosed in Japanese Patent Application Laid-Open No. 55-5851.
No. 6,009,045. FIG. 2 shows a capacitor film that has been conventionally used. The polymer film 1 shown in FIG. 3 has aluminum (Al) as a main component on both sides by a vacuum evaporation method, an ion plating method, or the like. Using a metallized film 13 formed with a metal thin film layer 3 and margins 4 and 5 having no metal thin film layer, a dielectric paint in which polycarbonate, polyphenylene oxide, or polyarylate is dissolved in an organic solvent is applied to both surfaces or one surface of the metallized film 13. It is applied so that the dielectric 9 as shown in FIG. 2 is formed. Here, reference numeral 10 denotes a margin portion formed simultaneously with the application of the dielectric paint, where the dielectric paint is not applied, and reference numeral 11 denotes a margin in the case of double-sided application. Then, the organic solvent contained as a diluent in the dielectric paint is dried and evaporated to obtain a capacitor film 12. As the organic solvent used here, a plurality of organic solvents are selected from dichloromethane, dichloroethane, trichloroethylene and the like. Conventionally, an ultraviolet curable resin is used as a dielectric paint for forming a dielectric film, and a capacitor film 18 as shown in FIG. 4 is used for a film capacitor. The capacitor film 18 is coated on at least one surface of the metallized film 13 with an ultraviolet-curing resin so that the dielectric 14 as shown in FIG. 4 is formed. It is obtained by curing the resin to form the dielectric 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-sided application. The dielectric paint constituting the dielectric 14 is obtained by adding a photopolymerization initiator for causing a curing reaction of the ultraviolet-curable resin to an ultraviolet-curable resin, and can be coated without a solvent.

[0003]

However, in the conventional capacitor film, a dielectric layer is formed by dissolving a polymer compound used for a dielectric in an organic solvent and applying the solution. Unless an organic solvent is used, the polymer compound cannot be dissolved, and there are problems that a heat source and a cooling device or a high-performance solvent recovery device for vaporizing and removing the organic solvent are required. Further, a capacitor film in which the dielectric is made of an ultraviolet-curable resin and having a low degree of reduction of C = C double bonds (hereinafter referred to as a degree of polymerization) in the dielectric may cause blocking when the coating film is wound. And the capacitor characteristics were degraded. Further, the conventional dielectric paint using an organic solvent as a diluent, a film is formed according to the surface shape of the polymer film to be a substrate, the coating film thickness with respect to the polymer film was uniform, Since the ultraviolet-curable resin is applied without a solvent, it wets regardless of the surface shape of the polymer film, and thus the thickness of the coating film on the polymer film becomes non-uniform and the withstand voltage characteristics are reduced. Further, in order to improve the productivity of the capacitor film in which the dielectric material for securing the capacitor characteristics is the ultraviolet-curable resin, a photopolymerization initiator (Chem. 6) is added. There has been a problem that the productivity of the capacitor film is reduced, and the capacitor characteristics are deteriorated.

[0004]

In order to solve the above-mentioned problems, dimethylol tricyclodecane diacrylate (Chem. 4) and 2-ethylhexyl acrylate (Chem. 5), which are UV-curable resins capable of solventless coating, are used. The degree of polymerization of the dielectric of the capacitor film coated and formed with the dielectric coating mainly composed of the ultraviolet curable resin is 7
0% or more, and the surface shape of the polymer film is Ra (Formula 2) = 0.025 to 0.035 μm, R _MAX = 0.25
A polymer film represented by -0.49 μm was used as a film for a capacitor. Further, the photopolymerization initiator (Chem. 6) is added to the ultraviolet curable resin and the photopolymerization initiator in a weight ratio of 10
The range was from 0 to 1 to 100 to 5.

[0005]

(Equation 2)

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION
At least one surface of 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, is provided with dimethylol tricyclodecane diacrylate 4) A dielectric material formed by applying a dielectric coating mainly composed of an ultraviolet-curable resin composed of 2-ethylhexyl acrylate (Chemical Formula 5) and having a reduction rate of C = C double bonds of 70% or more. Thus, the capacitor characteristics can be improved and stabilized. In addition, since it is solventless, it is harmless to the human body, protects the environment, and further reduces the size of equipment.

According to a second aspect of the present invention, there is provided a dielectric material comprising the dielectric coating according to the first aspect, wherein the weight ratio of the dielectric coating and the photopolymerization initiator (Chemical Formula 6) is in the range of 100: 1 to 100: 5. It is characterized by being coated with a paint, and can be produced with high efficiency without deteriorating the capacitor characteristics.

According to a third aspect of the present invention, the polymer film according to the first aspect has an average surface roughness (Equation 2) of 0.025 to 0.025.
Maximum height of 0.25 to 0.49 in the range of 0.035 μm
A polymer film having a thickness in the range of μm is used as a film for a capacitor, and the film thickness of a dielectric material on a substrate is made uniform to improve electrical characteristics.

According to a fourth aspect of the present invention, the polymer film is made of polypropylene (PP), polyethylene terephthalate (PET), polyethylene naphthalate (PEN),
A film for capacitors characterized by being polyphenylene sulfide (PPS), and 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. It is.

An embodiment of the present invention will be described below with reference to the drawings.

(Embodiment 1) FIG. 3 is a cross-sectional view of a metallized film manufactured by a vacuum evaporation method. In FIG. 3, metallized film 13 is a polymer film 1 made of polyethylene terephthalate (hereinafter referred to as PET). Each is composed of a metal thin film layer mainly composed of aluminum (Al) and margins 4 and 5 having no metal thin film layer. FIG. 1 is a sectional view of a capacitor film 7 of the present invention. In FIG. 1, a capacitor film 7 is composed of a dielectric 2 obtained by curing a dielectric coating mainly composed of an acrylate resin on one side of the metallized film 13 by ultraviolet irradiation, and margins 4 and 5 without the dielectric 2. ing. The capacitor film according to the present invention is characterized in that the dielectric is an acrylate resin, dimethylol tricyclodecane diacrylate.

[0012]

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2-ethylhexyl acrylate

[0014]

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These two components are the main components, and they are mixed so that the weight ratio of (Chemical Formula 4) to (Chemical Formula 5) is 90:10 to obtain an ultraviolet curable resin which is a main component of the dielectric coating material. Further, assuming that the ultraviolet-curable resin is 100, 2-methyl-1- [4- (methylthio) phenyl] -2-monforinopropanone-1 which is a photopolymerization initiator

[0016]

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Is added so that the weight ratio becomes 100: 2, and the mixture is thoroughly stirred and completely dissolved to obtain a dielectric coating material for forming a dielectric with the capacitor film of the present invention. In evaluating the capacitor film of the present invention with a multilayer capacitor, the dielectric paint contains an ethylene-vinyl acetate copolymer (hereinafter referred to as EVA) which is a thermoplastic resin which promotes interlayer adhesion of the capacitor film. )

[0018]

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When the dielectric coating material containing 2 parts of the above-mentioned photopolymerization initiator is taken as 100, the amount by weight is 100: 1. The dielectric paint obtained by blending the acrylate resin, the photopolymerization initiator and the thermoplastic resin in this manner is applied to the metallized film 13 shown in FIG. 3 at 50 m / min by a microgravure coater. 13, the dielectric paint is applied and formed, and the dielectric paint is cured by irradiating ultraviolet rays in an ultraviolet curing furnace filled with nitrogen gas and having an oxygen concentration of 900 ppm or less to obtain a capacitor film 7. . Here, in the ultraviolet curing furnace, a high-pressure mercury lamp of 160 (w / cm) is used as a film for capacitor 7 and 25 (cm).
UV rays are radiated from a distance. At this time, the polymerization degree of the dielectric formed on the capacitor film 7 is FT.
-It was 80% as measured by the IR method. Next, the same dielectric coating as that of the capacitor film 7 is applied and formed at a rate of 100 m / min.
The high-pressure mercury lamp, which is not more than
/ Cm), a capacitor film 19 having the same structure as that of the capacitor film 7 cured by irradiating ultraviolet rays in an ultraviolet curing furnace having the same composition as that of the capacitor film 7 was obtained. A degree of polymerization of 65% was obtained. Here, the film 7 for a capacitor and the film 19 for a capacitor were manufactured and evaluated by a conventional method for manufacturing a laminated film capacitor. FIG. 5 shows a comparison of the capacitor characteristics of a laminated film capacitor using the capacitor film 7 and the capacitor film 19. Here, the capacitor film 19 has the same structure as the capacitor film 7 and is used for comparison. As is clear from FIG. 5, the capacitor using the capacitor film having a degree of polymerization of 80% has more stable capacitor characteristics and a higher level. Compared with conventional dielectric paints, the frequency, impedance, and temperature characteristics are at the same level, the water absorption is low, and better results are obtained in solder heat resistance, high temperature load test, and moisture resistance load test. Can be

(Embodiment 2) In the dielectric coating material according to Embodiment 1, the photopolymerization initiator (Chemical Formula 6) is 0.5 parts by weight and 5.5 parts by weight, respectively, with respect to the acrylate resin. Is coated on one surface of the metallized film 13 by a micro gravure coater at 50 m / min, filled with nitrogen gas and supplied with an oxygen concentration of 900 p.
pm or less in an ultraviolet curing furnace to cure the dielectric coating under the same conditions, to obtain a capacitor film 20 shown in FIG. 10 and a capacitor film 21 shown in FIG. FIG. 6 shows the capacitor characteristics of the film capacitor manufactured in the first embodiment using each of the films 20, 21 and 7. The capacitor films 20 and 21 have the same structure as the capacitor film 7 and were used for comparison with the capacitor film 7. Here, it is clear from FIG. 6 that the capacitor film 20 has a tackiness on the dielectric surface and hinders high-efficiency production, and the capacitor characteristics are also deteriorated from FIG. It is also clear that the capacitor using the capacitor film 21 also has deteriorated capacitor characteristics.

(Embodiment 3) The dielectric paint described in Embodiment 1 has a surface shape of Ra (Equation 2) = 0.
In the range of 035 μm, R _MAX = 0.25 to 0.60 μm
The surface of P is smoother than that of conventional PET.
The surface shape of the coating film surface when applied to a metallized film provided with a metal thin film layer on ET and the conventional P
FIG. 7A shows a surface shape when the dielectric paint is applied to the metallized film 13 using ET in the same manner.
This is shown in comparison with FIG. FIG. 8 (a) of FIG.
3A and 3B show the breakdown voltage in comparison. As is clear from FIG. 8, it is recognized that the dielectric breakdown voltage is improved as compared with the case using the conventional PET.

[0022]

As described above, a dielectric mainly composed of an ultraviolet curable resin composed of dimethylol tricyclodecane diacrylate (Chem. 4) and 2-ethylhexyl acrylate (Chem. 5), which are acrylate resins. By setting the degree of polymerization of the dielectric material coated with the coating material to 70% or more, it is possible to produce a large amount of capacitor films at a time with high quality, low cost, resource saving and safety, and improve and stabilize the capacitor characteristics. I can do it. In addition, the content of the photopolymerization initiator is set to 100 to 1 to 10 in weight ratio with respect to the dielectric paint.
By setting the ratio to 0: 5, coating and curing can be performed at high speed, efficient production can be performed, and capacitor characteristics can be improved. Furthermore, PE with a smooth surface
By using T, the dielectric breakdown voltage of the sheet can be improved, and the capacitor characteristics can be improved.

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 a specific material, numerical values, and a method of forming a dielectric have been described as a microgravure coater, they explain the details of the present invention, and the present invention is not limited thereto.

[Brief description of the drawings]

FIG. 1 is a sectional view of a film for a capacitor of the present invention.

FIG. 2 is a cross-sectional view of a conventional capacitor film.

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

FIG. 4 is a cross-sectional view of a conventional capacitor film using a UV-curable resin as a dielectric paint.

FIG. 5 is a diagram showing a comparison of capacitor characteristics depending on the degree of dielectric polymerization.

FIG. 6 is a diagram showing a comparison of capacitor characteristics according to the amount of photopolymerization initiator charged.

FIG. 7 (a) is a cross-sectional view of a coating type metallized film obtained by applying a dielectric coating of an ultraviolet curable resin to PET of the present invention. (B) A coating type metallized film obtained by applying a dielectric coating of an ultraviolet curable resin to conventional PET. Cross section of film

FIG. 8 is a diagram showing a comparison of dielectric breakdown voltage between conventional PET and surface smooth PET.

FIG. 9 is a cross-sectional view of a film for a capacitor in which the degree of polymerization of a dielectric is 65%.

FIG. 10 is a cross-sectional view of a capacitor film in which a photopolymerization initiator is 0.5 parts by weight.

FIG. 11 is a cross-sectional view of a film for a capacitor in which a photopolymerization initiator is 5.5 parts by weight.

[Explanation of symbols]

REFERENCE SIGNS LIST 1 polymer film 2 dielectric 3 metal thin film layer 4, 5 margin 6 margin 7 film for capacitor of the present invention 8, 9 conventional dielectric layer made of conventional dielectric paint using organic solvent as diluent 10, 11 margin 12 Conventional capacitor films 13 Metallized films 14, 17 Dielectrics composed of conventional UV-curable resins 15, 16 Margins 18 Conventional capacitor films formed of UV-curable resins 19 Capacitors with a dielectric polymerization degree of 65% Film for capacitor 20 Film for capacitor in which photopolymerization initiator is 0.5 parts by weight 21 Film for capacitor in which photopolymerization initiator is 5.5 parts by weight

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Toshiyuki Inagaki 1006 Kazuma Kadoma, Osaka Pref. Matsushita Electric Industrial Co., Ltd. Terms (reference) 5E082 AB03 BC40 EE07 EE08 EE24 EE37 FF15 FG34 FG35 FG36 MM06 PP03 PP04 PP10

Claims (4)

[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. Decane diacrylate And 2-ethylhexyl acrylate The reduction rate of the C = C double bond of the dielectric formed by applying a dielectric coating mainly composed of an ultraviolet curable resin composed of
0% or more of a film for a capacitor. 2. The dielectric coating composition according to claim 1, wherein said dielectric coating composition is combined with a photopolymerization initiator. A film for a capacitor, wherein a dielectric paint containing a weight ratio of 100: 1 to 100: 5 is applied and formed. 3. The polymer film according to claim 1, wherein the average surface roughness (Equation 1) is in the range of 0.025 to 0.035 μm and the maximum height is in the range of 0.25 to 0.49 μm. Characteristic film for capacitors. (Equation 1) 4. The polymer film according to claim 3, wherein the polymer film is polypropylene (PP), polyethylene terephthalate (PE).
T), polyethylene naphthalate (PEN), and polyphenylene sulfide (PPS).