JPH0737765A - Electrolytic capacitor - Google Patents

Abstract

PURPOSE:To realize excellent tone quality by applying an electrode foil subjected to oxygen plasma treatment to at least either one of electrode foils. CONSTITUTION:Both surfaces of an aluminum foil on which surfaces dielectric oxide films are formed by a formation process are subjected to high frequency oxygen plasma treatment, and the aluminum foil is applied to an anode foil. An aluminum cathode foil and a separator paper composed of mixed paper of manila paper and floss silk fiber are prepared. A capacitor element is manufactured by winding the anode foil and the cathode foil, interposing the separator paper, and impregnated with driving electrolyte composed of water content, ethylene glycol, and ammonium adipate, thereby manufacturing a JIS-04 type electrolytic capacitor, which can obtain excellent regenerative sound. The impedance of the electrolytic capacitor in a high frequency band can be lowered.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrolytic capacitor using an electrode foil whose surface is treated with oxygen plasma,
More specifically, it relates to an electrolytic capacitor suitable for acoustics.

[0002]

2. Description of the Related Art Generally, an electrolytic capacitor has a capacitor element formed by winding an anode foil and a cathode foil made of a valve metal such as aluminum with a separator paper interposed therebetween, and the capacitor element is impregnated with a driving electrolytic solution. After that, the capacitor element is housed in a case made of metal such as aluminum or a case made of synthetic resin and hermetically sealed. Such electrolytic capacitors are JIS-04 type, 62 type, 6 type.
It corresponds to type 9 and so on.

As one of the anode foils of the electrode foil for an electrolytic capacitor, aluminum foil is generally chemically or electrochemically etched to increase its surface area, and a dielectric oxide film is formed by chemical conversion treatment. Used for.
In some cases, a flat (flat) aluminum foil having a dielectric oxide film formed thereon may be used without etching.

As the other cathode foil of the electrolytic capacitor electrode foil, an aluminum foil which is chemically or electrochemically etched to increase its surface area, or a plain (flat) aluminum foil without etching is used. It is usually used as it is, but a product having a dielectric oxide film formed may also be used.

As an electrolytic solution for driving an electrolytic capacitor,
An electrolyte solution in which a simple substance or a mixture of organic polar solvents such as ethylene glycol and γ-butyrolactone is used as a main solvent, and a carboxylic acid or a salt thereof is used as a solute, and saccharides, water, phosphoric acid, etc. are dissolved as additives if necessary. Is commonly used. Boric acid or its salt may be used as a solute.

[0006]

The electrolytic capacitor used for audio is used as a filter capacitor on the secondary side of a power supply circuit, a capacitor for coupling between amplifiers, or a capacitor for speaker networks. It is required to obtain excellent playback sound quality.
However, it cannot be said that the electrolytic capacitors used for conventional audio have necessarily obtained excellent reproduced sound quality.

An object of the present invention is to provide an electrolytic capacitor for acoustic use having excellent sound quality characteristics.

[0008]

In order to solve such a problem, the present inventors have conducted various experiments and studies, and as a result, at least one of the electrode foils has been subjected to oxygen plasma treatment. It was found that the electrolytic capacitor can provide an excellent reproduced sound when used.

The oxygen plasma treatment according to the present invention means that the base material is placed under a low pressure, and high-frequency energy is applied to the oxygen gas to bring the oxygen gas into a plasma state containing almost the same number of cations and electrons. The surface of the electrode foil is modified with atomic oxygen, which is rich in properties.

When performing such an oxygen plasma treatment, the degree of vacuum is 1 to 10 Torr and the oxygen flow rate is 50 to 10.
0ml / min is desirable, oscillation frequency is 5-30MH
A high frequency of z is preferably used. The high frequency output is preferably in the range of 10 to 200W. Furthermore, the treatment time depends on the thickness of the anodized film, but is preferably 1 minute to 24 hours.

The thickness of the aluminum foil is 10 to 2
One having a diameter of 00 μm is used. The aluminum foil having a purity of 99.0% or more is used. Particularly, as the aluminum foil for the anode, one having a purity of 99.9% or more is suitable. As the aluminum foil for the cathode, one having a purity of 99.5% or more is preferably used.
In addition, an aluminum foil for the cathode may be an alloy foil with copper.

As the organic polar solvent of the driving electrolytic solution used in the present invention, any organic polar solvent usually used for electrolytic capacitors can be used. Preferred solvents include amides, lactones, glycols,
Sulfur compounds, ketones, ethers or carbonates can be used.

Preferred specific examples include propylene carbonate, N, N-dimethylformamide, N-methylformamide, γ-butyrolactone, N-methylpyrrolidone,
Dimethyl sulfoxide, ethylene cyanohydrin, ethylene glycol, ethylene glycol mono- or dialkyl ether, 3-alkyl-1,3-oxazolidin-2-one and the like can be used. Particularly preferably, lactones and ethylene glycols are used.

As the solute of the driving electrolytic solution used in the present invention, any solute commonly used in electrolytic capacitors can be used.

Preferred solutes are inorganic acids such as boric acid and phosphoric acid or salts thereof, heteropolyacids such as silicotungstic acid or salts thereof, organic acids having phenolic hydroxyl groups or salts thereof, organic acids having sulfonic acid groups. Or a salt thereof, a chain monocarboxylic acid represented by formic acid or dodecyl acid or a salt thereof, an aromatic monocarboxylic acid represented by benzoic acid or salicylic acid or a salt thereof, a chain dicarboxylic acid represented by adipic acid or sebacic acid. Acid or its salt,
Examples thereof include unsaturated dicarboxylic acids such as maleic acid and citraconic acid or salts thereof, cyclic dicarboxylic acids consisting of phthalic acid, nitrophthalic acid or tetrahydrophthalic acid or salts thereof, and tricarboxylic acids represented by citric acid or salts thereof. it can. Particularly preferably, a quaternary alkyl ammonium salt of an aromatic carboxylic acid or an unsaturated dicarboxylic acid and an ammonium salt of an aromatic carboxylic acid are used.

As the salt, ammonium salts, first to
Examples thereof include tertiary amine salts and quaternary ammonium salts. Also, water is added to increase conductivity,
15% or less, preferably 8% or less, and particularly preferably 5% or less is adopted in order to prevent the capacitor characteristics from changing with time.

[0017]

[Function] A dielectric oxide film generally used for electrolytic capacitors is an aqueous solution in which an inorganic acid such as boric acid or a salt thereof and an organic acid such as a chain dicarboxylic acid represented by adipic acid or a salt thereof are dissolved. It is electrochemically formed therein, but at that time, these acids and water are taken into the dielectric oxide film.

The portion containing these acids and water becomes a defective portion in the dielectric oxide film and is easily corroded by the electrolytic solution for driving the electrolytic capacitor, resulting in deterioration of various characteristics of the electrolytic capacitor such as increase of leakage current.

The oxygen plasma treatment used in the present invention acts on the defective portion existing on the surface of the electrode foil, decomposes and removes water contained in the defective portion, and improves the oxidation state of the dielectric oxide film.

As a result, the plasma-treated film has good chemical stability, that is, excellent chemical resistance, and therefore is effectively protected from the electrolytic solution for driving the electrolytic capacitor.

[0021]

EXAMPLES Example 1 An oscillation frequency of 13.56 was applied to both sides of an aluminum foil (purity: 99.9%) having a thickness of 80 μm and a dielectric oxide film formed on both sides by a conventional chemical conversion treatment.
Output power 100W, oxygen flow rate 100ml / at high frequency of MHz
Oxygen plasma treatment was performed for 3 minutes under the conditions of min and vacuum degree of 1.5 Torr, and this was used as an anode foil. Also, thickness 8
An aluminum cathode foil with a thickness of 0 μm and a purity of 99.9% and a separator paper with a thickness of 50 μm made of a mixed paper of Manila hemp and cotton fiber were prepared. A capacitor element is manufactured by winding these anode foil and cathode foil via a separator paper, and the capacitor element is impregnated with a driving electrolyte solution containing 12 wt% of water, 74 wt% of ethylene glycol, and 14 wt% of ammonium adipate, A JIS-04 type electrolytic capacitor having a rating of 63V 56 μF, an outer diameter of 8 mm and a length of 20 mm was manufactured. Capacitance is 62.3μF, 1MH
The impedance at z was 0.182Ω.

Example 2 An oscillation frequency of 13.5 was applied to both sides of an aluminum foil (purity: 99.9%) having a thickness of 80 μm and a dielectric oxide film formed on both sides by a conventional chemical conversion treatment.
Output power of 30 W at high frequency of 6 MHz, oxygen flow rate of 50 ml / m
Oxygen plasma treatment was performed for 3 minutes under conditions of in and vacuum degree of 1.5 Torr, and this was used as a cathode foil. On the contrary,
Aluminum foil with a thickness of 80 μm and a purity of 99.9% and a thickness of 50 μm made from a mixed paper of Manila hemp and cotton fiber
And a separator paper were prepared. A capacitor element is manufactured by winding these cathode foil and anode foil through a separator paper, and the capacitor element has water of 12 wt%, ethylene glycol of 74 wt%, and ammonium adipate of 14 wt%.
% Impregnated with a driving electrolyte solution of 63% and rated at 63V 56μ
A JIS-04 type electrolytic capacitor having F, an outer diameter of 8 mm and a length of 20 mm was manufactured. The capacitance was 62.1 μF and the impedance at 1 MHz was 0.185 Ω.

Example 3 An oscillation frequency of 13.5 was applied to both sides of an aluminum foil (purity: 99.9%) having a thickness of 80 μm and a dielectric oxide film formed on both sides by a conventional chemical conversion treatment.
Output power 100W, oxygen flow rate 100ml at high frequency of 6MHz
/ Min, the degree of vacuum was 1.5 Torr, and oxygen plasma treatment was performed for 3 minutes to obtain an anode foil. An aluminum foil having a thickness of 80 μm and a purity of 99.9% was subjected to oxygen plasma treatment under the same conditions to obtain a cathode foil. These anode foil and cathode foil are wound around a separator paper made of a mixed paper of Manila hemp and cotton fiber and having a thickness of 50 μm to produce a capacitor element.
A JIS-04 type electrolytic capacitor having a rating of 63V 56 μF, an outer diameter of 8 mm, and a length of 20 mm was manufactured by impregnating a driving electrolytic solution containing wt%, ethylene glycol 74 wt%, and ammonium adipate 14 wt%. The capacitance was 62.4 μF and the impedance at 1 MHz was 0.183Ω.

Comparative Example 80 μm thick aluminum (purity 99.9%) anode foil having a dielectric oxide film formed on both sides by a conventional chemical conversion treatment, and 80 μm thick aluminum (purity 99.9%). A cathode foil and separator paper having a thickness of 50 μm and made of a mixed paper of Manila hemp and cotton fiber were prepared. These cathode foil and anode foil are wound with a separator paper between them to manufacture a capacitor element, and this capacitor element is impregnated with a driving electrolyte solution containing 12 wt% of water, 74 wt% of ethylene glycol, and 14 wt% of ammonium adipate, Rating 63V 56μF, outer diameter 8mm, length 2
A 0 mm JIS-04 type electrolytic capacitor was manufactured.
The capacitance was 61.1 μF and the impedance at 1 MHz was 0.186Ω.

Next, the electrolytic capacitors of Examples 1, 2, 3 and Comparative Example were used as coupling capacitors between amplifiers, and these capacitors were replaced with each other to watch a CD (compact disc).

According to the viewing result of Example 1, the resolution in the low frequency range was good and the reproducibility of minute sounds was excellent.

According to the viewing results of Example 2, the sound was localized well, the vocal thickness was increased, and the high resolution was excellent.

According to the viewing result of Example 3, the thickness of the low frequency band is increased and the texture of the middle and high frequency bands is improved.

On the other hand, in the viewing result of the comparative example, the sound image was unpleasant, opaque, the amount of information was small, and the sound was scattered over the entire area.

[0030]

As described above, according to the present invention, a good reproduced sound can be obtained by subjecting at least one of the electrode foil surfaces to the oxygen plasma treatment. Further, the impedance of the electrolytic capacitor in the high frequency band can be lowered.

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[Procedure amendment]

[Submission date] September 20, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] 0025

[Correction method] Change

[Correction content]

Next, the electrolytic capacitors of Examples 1, 2, 3 and Comparative Example were used as coupling capacitors between the amplifiers, and these capacitors were replaced with each other to listen to a CD (compact disc).

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0026

[Correction method] Change

[Correction content]

According to the results of the trial listening of Example 1, the resolution in the low frequency range was good and the reproducibility of minute sounds was excellent.

[Procedure 3]

[Document name to be amended] Statement

[Name of item to be corrected] 0027

[Correction method] Change

[Correction content]

According to the results of the trial listening of Example 2, the sound localization was good, the vocal thickness was increased, and the high resolution was excellent.

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0028

[Correction method] Change

[Correction content]

According to the results of the trial listening of Example 3, the thickness in the low frequency region was increased and the texture in the middle and high frequency regions was improved.

[Procedure Amendment 5]

[Document name to be amended] Statement

[Name of item to be corrected] 0029

[Correction method] Change

[Correction content]

On the other hand, according to the results of the trial listening of the comparative example, the sound image was soft, opaque, the amount of information was small, and the sound was diffused over the entire area.

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Yasuhiko Soga 2-2-1 Tsujido Shinmachi, Fujisawa City, Kanagawa Elner Co., Ltd.

Claims (1)

[Claims] 1. An electrolytic capacitor in which a driving electrolytic solution is impregnated in a capacitor element in which an anode foil and a cathode foil, each having a dielectric oxide film formed on at least one of them, are wound with separator paper interposed therebetween. An electrolytic capacitor characterized in that one of the electrode foils is an oxygen-treated electrode foil.