JP4030416B2 - Electrolytic solution for driving electrolytic capacitors - Google Patents

Description

【０００９】
本発明において、上記トリプトファンの溶解量は、電解液全体に対して０．１〜１．０ｗｔ％であることが好ましい。０．１ｗｔ％未満では十分な効果が得られず、１．０ｗｔ％を超えると比抵抗が高くなる傾向にある。
【００１０】
本発明において、水の混合量は電解液全体に対して、２．０〜１０．０ｗｔ％であることが好ましい。２．０ｗｔ％未満では比抵抗がやや高く、１０．０ｗｔ％を超えると、トリプトファンの効果が低下する傾向にある。
【００１１】
本発明において、上記カルボン酸としては、アゼライン酸、セバシン酸、１、６−デカンジカルボン酸、５、６−デカンジカルボン酸、７−ビニルヘキサデセン−１、１６−ジカルボン酸等を例示することができる。
【００１２】
また、カルボン酸の塩としては、アンモニウム塩の他、メチルアミン、エチルアミン、ｔ−ブチルアミン等の一級アミン塩、ジメチルアミン、エチルメチルアミン、ジエチルアミン等の二級アミン塩、トリメチルアミン、ジエチルメチルアミン、エチルジメチルアミン、トリエチルアミン等の三級アミン塩、テトラメチルアンモニウム、トリエチルメチルアンモニウム等の四級アンモニウム塩等を例示することができる。
【００１３】
多価アルコールとしては、エチレングリコール、プロピレングリコール、ジエチレングリコール、トリエチレングリコール、グリセリン等を例示することができる。
【００１４】
【発明の実施の形態】
本発明に係る電解液では、少なくともエチレングリコールなどの多価アルコールと水とを混合した溶媒に、少なくとも、カルボン酸またはその塩と、トリプトファンとを配合する。ここで、トリプトファンの溶解量については、例えば、電解液全体に対して０．１〜１．０ｗｔ％とする。また、水の混合量については、電解液全体に対して２．０〜１０．０ｗｔ％とする。
【００１５】
本発明に係る電解液では、電解液中のトリプトファンが電極箔表面に吸着するため、水の添加量が増加しても１０５℃の高温下での水と電極箔との水和反応を抑制でき、高温無負荷時の漏れ電流増大を抑制することができる。また電解質の増量を必要としないので、耐電圧が低下することもない。
【００１６】
【実施例】
以下、本発明の実施例を具体的に説明する。表１、２の組成で電解液を調合し、３０℃における比抵抗を測定した結果を表１、２に示す。
【００１７】
【表１】

【００１８】
【表２】

【００１９】
次に、表１、２に示す各電解液を使用して、定格４００Ｖ−２２μＦ（φ１６×２５ｍｍＬ）の電解コンデンサを各１０個を作製し、ｔａｎδ、漏れ電流について初期特性測定後、高温無負荷試験（１０５℃、１０００時間放置）を行い、表３の結果を得た。
【００２０】
【表３】

【００２１】
表３に示すように、トリプトファンを溶解しなかった従来例１〜３と比較し、本発明の実施例１〜９では高温無負荷試験において漏れ電流の増大が抑制され、優れた特性を示している。
【００２２】
なお、トリプトファンの溶解量は０．１〜１．０ｗｔ％の範囲が好ましい。０．１ｗｔ％未満では十分な効果が得られず、低漏れ電流用途に不向きであり、１．０ｗｔ％を超えると比抵抗が高くなり、低比抵抗用途に不向きとなる。
【００２３】
また、水の混合量は２．０〜１０．０ｗｔ％の範囲が好ましく、２．０ｗｔ％未満では比抵抗がやや高いので、低比抵抗用途に不向きであり、１０．０ｗｔ％を超えると、トリプトファンの効果が低下するので好ましくない。
【００２４】
なお、本発明は、上記実施例に限定されるものではなく、先に例示したカルボン酸またはその塩を単独または複数溶解しても、同様の効果がある。また、必要により、耐洗浄剤としてニトロ化合物を溶解してもよい。
【００２５】
【発明の効果】
以上説明したように、本発明によるトリプトファンを溶解した電解液は、エチレングリコールなどの多価アルコールと水との混合溶媒に溶解し易く、かつ、水を含有していても高温下での電極箔と水との水和反応を抑制し、高温無負荷での信頼性に優れるため、電解コンデンサの特性改善並びに信頼性向上を図ることができる。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an improvement in an electrolytic solution for driving an electrolytic capacitor (hereinafter referred to as an electrolytic solution).
[0002]
[Prior art]
In recent years, with the miniaturization of electrolytic capacitors, those having a high etching magnification have been used for the anode foil of electrolytic capacitors, and electrolytes having a low specific resistance are required.
As such an electrolytic solution, conventionally, a solution in which ethylene glycol is used as a main solvent and an ammonium salt of carboxylic acid is dissolved as an electrolyte is used (for example, see Patent Documents 1 and 2).
[0003]
[Patent Document 1]
Japanese Patent Publication No. 7-48460 (2nd page, table)
[Patent Document 2]
Japanese Patent Publication No. 7-63047 (Page 3, Table 1)
[0004]
[Problems to be solved by the invention]
To obtain a low specific resistance electrolyte solution, the electrolyte concentration must be increased or a large amount of water must be added. However, there is a problem that an increase in the concentration of the electrolyte causes precipitation of the electrolyte and a decrease in withstand voltage. Also, when a large amount of water is added, the leakage current at high temperature and no load of the electrolytic capacitor is increased, so that it is difficult to use at 105 ° C.
[0005]
In view of the above problems, an object of the present invention is to provide an electrolytic solution for driving an electrolytic capacitor that has a low specific resistance and can be used even under high temperature conditions.
[0006]
[Means for Solving the Problems]
In order to solve the above problems, in the present invention, by dissolving tryptophan in the electrolytic solution, the hydration reaction between the electrode foil and water at high temperature is suppressed, and the electrolytic solution has excellent reliability at high temperature and no load. Is to provide.
[0007]
That is, the electrolytic solution according to the present invention is characterized in that carboxylic acid or a salt thereof and tryptophan represented by the following chemical formula are dissolved in a mixed solvent of a polyhydric alcohol such as ethylene glycol and water.
[0008]
[Chemical 2]

[0009]
In the present invention, the amount of tryptophan dissolved is preferably 0.1 to 1.0 wt% with respect to the entire electrolyte. If it is less than 0.1 wt%, a sufficient effect cannot be obtained, and if it exceeds 1.0 wt%, the specific resistance tends to increase.
[0010]
In the present invention, the amount of water mixed is preferably 2.0 to 10.0 wt% with respect to the entire electrolytic solution. If it is less than 2.0 wt%, the specific resistance is somewhat high, and if it exceeds 10.0 wt%, the effect of tryptophan tends to be reduced.
[0011]
In the present invention, examples of the carboxylic acid include azelaic acid, sebacic acid, 1,6-decanedicarboxylic acid, 5,6-decanedicarboxylic acid, 7-vinylhexadecene-1,16-dicarboxylic acid, and the like. .
[0012]
In addition to ammonium salts, primary amine salts such as methylamine, ethylamine and t-butylamine, secondary amine salts such as dimethylamine, ethylmethylamine and diethylamine, trimethylamine, diethylmethylamine and ethyl Examples thereof include tertiary amine salts such as dimethylamine and triethylamine, and quaternary ammonium salts such as tetramethylammonium and triethylmethylammonium.
[0013]
Examples of the polyhydric alcohol include ethylene glycol, propylene glycol, diethylene glycol, triethylene glycol, glycerin and the like.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
In the electrolytic solution according to the present invention, at least a carboxylic acid or a salt thereof and tryptophan are blended in a solvent in which a polyhydric alcohol such as ethylene glycol and water are mixed. Here, the amount of tryptophan dissolved is, for example, 0.1 to 1.0 wt% with respect to the entire electrolytic solution. Moreover, about the amount of water mixture, it is set as 2.0-10.0 wt% with respect to the whole electrolyte solution.
[0015]
In the electrolytic solution according to the present invention, since tryptophan in the electrolytic solution is adsorbed on the surface of the electrode foil, the hydration reaction between water and the electrode foil at a high temperature of 105 ° C. can be suppressed even when the amount of water added is increased. In addition, increase in leakage current at high temperature and no load can be suppressed. In addition, since the amount of electrolyte is not required, the withstand voltage is not lowered.
[0016]
【Example】
Examples of the present invention will be specifically described below. Tables 1 and 2 show the results of preparing electrolytic solutions with the compositions shown in Tables 1 and 2 and measuring the specific resistance at 30 ° C.
[0017]
[Table 1]

[0018]
[Table 2]

[0019]
Next, using each electrolytic solution shown in Tables 1 and 2, 10 electrolytic capacitors with a rating of 400V-22μF (φ16 × 25mmL) were prepared, and initial characteristics were measured for tan δ and leakage current. A test (105 ° C., 1000 hours) was performed, and the results shown in Table 3 were obtained.
[0020]
[Table 3]

[0021]
As shown in Table 3, compared with the conventional examples 1 to 3 in which tryptophan was not dissolved, in the examples 1 to 9 of the present invention, an increase in leakage current was suppressed in the high temperature no-load test, and excellent characteristics were shown. Yes.
[0022]
The amount of tryptophan dissolved is preferably in the range of 0.1 to 1.0 wt%. If it is less than 0.1 wt%, a sufficient effect cannot be obtained, and it is unsuitable for low leakage current applications. If it exceeds 1.0 wt%, the specific resistance becomes high and unsuitable for low specific resistance applications.
[0023]
Also, the amount of water mixed is preferably in the range of 2.0 to 10.0 wt%, and if it is less than 2.0 wt%, the specific resistance is slightly high, so it is not suitable for low specific resistance applications, and if it exceeds 10.0 wt%, Since the effect of tryptophan decreases, it is not preferable.
[0024]
In addition, this invention is not limited to the said Example, Even if it dissolves the carboxylic acid illustrated previously, or its salt individually or in multiple numbers, there exists the same effect. Further, if necessary, a nitro compound may be dissolved as a detergent-resistant agent.
[0025]
【The invention's effect】
As described above, the electrolytic solution in which tryptophan is dissolved according to the present invention is easily dissolved in a mixed solvent of polyhydric alcohol such as ethylene glycol and water, and the electrode foil under high temperature even if it contains water. Since the hydration reaction between water and water is suppressed and the reliability at high temperature and no load is excellent, the characteristics of the electrolytic capacitor can be improved and the reliability can be improved.

Claims (3)

An electrolytic solution for driving an electrolytic capacitor, wherein a carboxylic acid or a salt thereof and tryptophan represented by the following chemical formula are dissolved in a mixed solvent of a polyhydric alcohol and water.

2. The electrolytic solution for driving an electrolytic capacitor according to claim 1, wherein the amount of tryptophan dissolved is 0.1 to 1.0 wt% with respect to the entire electrolytic solution. 3. The electrolytic solution for driving an electrolytic capacitor according to claim 1, wherein the amount of water mixed is 2.0 to 10.0 wt% with respect to the entire electrolytic solution.