JP4282385B2 - Electrolytic solution for electrolytic capacitor drive - Google Patents

Description

【００１３】
表１の電解液で、直径１０．０ｍｍ、長さ１２．５ｍｍ、定格電圧３５０Ｖ、静電容量１０μＦのアルミニウム電解コンデンサを各１０個作製した。これらの製品を１０５℃の恒温槽中で３０００時間、定格電圧を印加し、静電容量とｔａｎδを測定し、表２の結果を得た。
【００１４】
【表２】

【００１５】
表２の結果より、Ｎ−オキシメチルステアロアミドを溶解した実施例は、従来例に比べて容量変化率、ｔａｎδの上昇が抑制されていることが分かる。表１、２の結果より、Ｎ−オキシメチルステアロアミドの電解液に対する溶解量は０．１〜１０．０ｗｔ％の範囲が好ましい。０．１ｗｔ％未満では容量変化率、ｔａｎδの上昇の抑制効果が十分ではなく、１０．０ｗｔ％を超えると電解液の比抵抗が上昇し、耐電圧が低下するため、不適当である。
【００１６】
なお、実施例ではＮ−オキシアルキルステアロアミドとして、Ｎ−オキシメチルステアロアミドを用いたが、Ｎ−オキシエチルステアロアミド、Ｎ−オキシプロピルステアロアミド、Ｎ−オキシ−ｉｓｏ−プロピルステアロアミドでも実施例と同等の効果があった。Ｎ−オキシブチルステアロアミドは溶解に時間を要するため、上記Ｎ−オキシアルキルステアロアミドが好ましい。
【００１７】
また、、本発明によるＮ−オキシアルキルステアロアミドの効果は、実施例に限定されるものではなく、先に例示した有機カルボン酸またはその塩を単独または複数溶解しても本実施例と同等の効果があった。
【００１８】
【発明の効果】
上記のとおり、本発明による電解液は、Ｎ−オキシアルキルステアロアミドを溶解することで、アルミニウム電極箔表面に水和酸化物が生成することを抑えられ、電解コンデンサの静電容量変化率、ｔａｎδ上昇を抑制することができ、電解コンデンサの信頼性の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]
Conventionally, an electrolytic solution of an electrolytic capacitor in which a polyhydric alcohol such as ethylene glycol is used as a main solvent and a carboxylic acid or an ammonium salt thereof is dissolved (see, for example, 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]
However, in the above electrolytic solution, water generated when the main solvent ethylene glycol and the organic carboxylic acid react and esterify, or water contained in the electrolytic paper in the electrolytic capacitor element Bonds with the oxide on the surface of the aluminum electrode foil at a high temperature to form a hydrated oxide. This hydrated oxide reduces the capacitance of the electrolytic capacitor, increases the loss, and decreases the reliability. There was a problem.
Therefore, an electrolytic solution having a composition capable of suppressing the formation of the hydrated oxide has been required.
[0005]
[Means for Solving the Problems]
The present invention has been found as a result of various studies to solve the above-mentioned problems, and has been found to dissolve an N-oxyalkyl stearamine such as N-oxymethyl stearamide having a waterproof effect in an electrolytic solution, By this, the production | generation of a hydrated oxide is going to be suppressed by covering the electrode foil surface.
That is, the present invention is a solvent composed mainly of ethylene glycol are dissolved with an organic carboxylic acid or a salt thereof, and boric acid or its ammonium salt, an N- oxyalkyl stearamide represented by the following formula, N -The electrolytic solution for driving an electrolytic capacitor , wherein the amount of oxyalkyl stearamide dissolved is 0.1 to 10.0 wt% with respect to the entire electrolytic solution.
[0007]
Furthermore, as the oxyalkyl group of the N-oxyalkyl stearamide, oxymethyl, oxyethyl, oxypropyl, and oxy-iso-propyl are preferable.
[0008]
Examples of the organic carboxylic acid include azelaic acid, sebacic acid, 1,6-decanedicarboxylic acid, 5,6-decanedicarboxylic acid, 7-vinylhexadecene-1,16-dicarboxylic acid and the like.
[0009]
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, triethylmethylammonium and tetraethylammonium.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
N-oxymethyl stearamide dissolved in the electrolytic solution of the present invention has a waterproof effect, and the effect lasts. Therefore, when adsorbed on the electrode foil surface, water binds to the oxide on the aluminum electrode foil surface. It is thought that the production of hydrated oxide can be suppressed. Therefore, the initial characteristics of the product can be maintained for a long time. Moreover, since it melt | dissolves in large quantities with respect to ethylene glycol, said effect becomes more reliable.
[0011]
【Example】
Examples of the present invention will be specifically described below. An electrolytic solution was prepared with the composition shown in Table 1, and the specific resistance of the electrolytic solution at 30 ° C. and the spark generation voltage (withstand voltage of the electrolytic solution) at 85 ° C. were measured.
[0012]
[Table 1]

[0013]
Ten aluminum electrolytic capacitors each having a diameter of 10.0 mm, a length of 12.5 mm, a rated voltage of 350 V, and a capacitance of 10 μF were produced from the electrolytic solution of Table 1. The rated voltage was applied to these products in a constant temperature bath at 105 ° C. for 3000 hours, the capacitance and tan δ were measured, and the results shown in Table 2 were obtained.
[0014]
[Table 2]

[0015]
From the results of Table 2, it can be seen that the examples in which N-oxymethyl stearoamide was dissolved suppressed the increase in capacity change rate and tan δ as compared with the conventional example. From the results of Tables 1 and 2, the amount of N-oxymethyl stearoamide dissolved in the electrolyte solution is preferably in the range of 0.1 to 10.0 wt%. If it is less than 0.1 wt%, the effect of suppressing the increase in capacity change rate and tan δ is not sufficient, and if it exceeds 10.0 wt%, the specific resistance of the electrolytic solution increases and the withstand voltage decreases, which is inappropriate.
[0016]
In the examples, N-oxymethyl stearamide was used as the N-oxyalkyl stearamide, but N-oxyethyl stearamide, N-oxypropyl stearamide, N-oxy-iso-propyl stearamide was used. Roamide also had the same effect as the example. Since N-oxybutyl stearamide requires time for dissolution, the above N-oxyalkyl stearamide is preferable.
[0017]
In addition, the effect of the N-oxyalkyl stearamide according to the present invention is not limited to the examples, and even if the organic carboxylic acid or the salt thereof exemplified above is dissolved alone or plurally, it is equivalent to this example. There was an effect.
[0018]
【The invention's effect】
As described above, the electrolytic solution according to the present invention can suppress the formation of hydrated oxide on the aluminum electrode foil surface by dissolving N-oxyalkyl stearamide, and the capacitance change rate of the electrolytic capacitor, An increase in tan δ can be suppressed, and the reliability of the electrolytic capacitor can be improved.

Claims (1)

Using ethylene glycol as the main solvent, organic carboxylic acid or its salt, boric acid or its ammonium salt, and N-oxyalkyl stearamide are dissolved, and the amount of N-oxyalkyl stearamide dissolved in the entire electrolyte solution An electrolytic solution for driving an electrolytic capacitor, wherein the electrolytic solution is 0.1 to 10.0 wt% with respect to the electrolyte.