JP4653355B2 - Electrolytic solution for electrolytic capacitor drive - Google Patents

Description

【０００６】
また、上記ポリ−Ｎ−ビニルカルバゾールの溶解量が、２．０ｗｔ％以下であることを特徴とする電解コンデンサの駆動用電解液である。
【０００７】
そして、上記有機カルボン酸としては、マレイン酸、フタル酸、安息香酸、アジピン酸、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。
【０００８】
さらに、有機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１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２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３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、テトラエチルアンモニウム等の４級アンモニウム塩等を例示することができる。
【０００９】
【発明の実施の形態】
ポリ−Ｎ−ビニルカルバゾール分子内のピロール環は電気的に陽性であり、電解コンデンサに電圧を加えることにより陰極箔側に移動する。そして、ポリ−Ｎ−ビニルカルバゾールの有するエチレン鎖が陰極箔を保護し、その結果水、酸などの影響から陰極箔を保護することができる。それにより、容量変化、ｔａｎδ増加を抑制することができ、電解コンデンサの信頼性を向上することができる。
【００１０】
【実施例】
本発明について実施例に基づき具体的に説明する。
表１の組成で電解液を調合し３０℃における比抵抗を測定した。
【００１１】
【表１】

【００１２】
陽極箔と陰極箔とをセパレータ紙を介して巻回したコンデンサ素子に表１の電解液を含浸した後、アルミニウム製外装ケース内に封口ゴムと共に挿入し、直径１０ｍｍ、長さ１２．５ｍｍ、定格電圧５０Ｖ、静電容量１５０μＦのアルミ電解コンデンサを各１０個製作しエージング処理を行った。
これらの製品を１０５℃の恒温槽中で定格電圧を３０００時間印加し、初期値に対する静電容量変化率とｔａｎδを測定し、表２の結果を得た。
【００１３】
【表２】

【００１４】
表２より、ポリ−Ｎ−ビニルカルバゾールを溶解した実施例は、従来例と比較して容量減少とｔａｎδ上昇が抑えられており優れた効果を有することが分かる。
【００１５】
なお、ポリ−Ｎ−ビニルカルバゾールの溶解量は、０．０５ｗｔ％では、ｔａｎδ上昇を抑制する効果が長期信頼性を要する用途向けには充分ではなく、５．０ｗｔ％では、電解液の比抵抗が高くなるので低比抵抗用途に不適であり、ポリ−Ｎ−ビニルカルバゾールの溶解量は、０．１０〜２．００ｗｔ％の範囲が好ましい。
【００１６】
また、ポリ−Ｎ−ビニルカルバゾールの効果は、実施例に限定されるものでなく、先に記載した化合物を単独または複数組み合わせて溶解した電解液においても、実施例と同等の効果がある。
【００１７】
【発明の効果】
上記のとおり本発明によるエチレングリコールと水との混合溶媒に、有機カルボン酸またはその塩と、ポリ−Ｎ−ビニルカルバゾールとを溶解した電解液を使用した電解コンデンサは、従来に比べ静電容量の減少とｔａｎδ上昇を抑制することができ、長期信頼性を向上させることが可能である。[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), and particularly relates to an electrolytic solution that can improve long-term reliability of a product.
[0002]
[Prior art]
Conventionally, electrolytic solutions for low-voltage electrolytic capacitors have long-term reliability of aluminum electrolytic capacitors by dissolving higher dibasic acid or its ammonium salt in a mixed solvent of ethylene glycol and water and adding additives such as mannitol and sorbitol. The sex was secured.
[0003]
[Problems to be solved by the invention]
However, long-term reliability of electrolytic capacitors can be improved by adding mannitol, sorbitol, etc., but phosphoric acid or organic carboxylic acid and polyhydric alcohols such as mannitol, sorbitol react to produce ester compounds. However, this ester compound generates amides due to heat generation inside the electrolytic capacitor, and this amides cause a chemical reaction due to oxygen gas generated at the anode, increasing the specific resistance of the electrolytic solution. There has been a demand for an electrolytic solution capable of improving the properties.
[0004]
[Means for Solving the Problems]
The present invention has been found as a result of studies to solve the above problems. Paying attention to the fact that the pyrrole ring in the poly-N-vinylcarbazole molecule is electrically positive and has a long ethylene chain, poly-N-vinylcarbazole is attracted to the cathode side when voltage is applied, protecting the aluminum foil This is intended to improve the reliability of the electrolytic capacitor. That is, an organic carboxylic acid or a salt thereof and poly-N-vinylcarbazole (Chemical Formula 2) are dissolved in a mixed solvent of ethylene glycol and water, and the amount of poly-N-vinylcarbazole dissolved is 0.1 to 0.1%. An electrolytic solution for driving an electrolytic capacitor characterized by being 5.0 wt% .
[0005]
[Chemical 2]

[0006]
The electrolytic solution for driving an electrolytic capacitor is characterized in that the amount of poly-N-vinylcarbazole dissolved is 2.0 wt% or less .
[0007]
Examples of the organic carboxylic acid include maleic acid, phthalic acid, benzoic acid, adipic acid, azelaic acid, sebacic acid, 1,6-decanedicarboxylic acid, 5,6-decanedicarboxylic acid, 7-vinylhexadecene-1, Examples thereof include 16-dicarboxylic acid.
[0008]
Furthermore, as salts of organic carboxylic acids, ammonium salts, primary amine salts such as methylamine, ethylamine and t-butylamine, secondary amine salts such as dimethylamine, ethylmethylamine and diethylamine, trimethylamine and diethylmethylamine And tertiary amine salts such as ethyldimethylamine and triethylamine, and quaternary ammonium salts such as tetramethylammonium, triethylmethylammonium and tetraethylammonium.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
The pyrrole ring in the poly-N-vinylcarbazole molecule is electrically positive and moves to the cathode foil side when a voltage is applied to the electrolytic capacitor. The ethylene chain of poly-N-vinylcarbazole protects the cathode foil, and as a result, the cathode foil can be protected from the influence of water, acid, and the like. Thereby, a change in capacitance and an increase in tan δ can be suppressed, and the reliability of the electrolytic capacitor can be improved.
[0010]
【Example】
The present invention will be specifically described based on examples.
An electrolyte solution was prepared with the composition shown in Table 1, and the specific resistance at 30 ° C. was measured.
[0011]
[Table 1]

[0012]
A capacitor element in which an anode foil and a cathode foil are wound through a separator paper is impregnated with the electrolytic solution shown in Table 1, and then inserted into an aluminum outer case together with a sealing rubber, and has a diameter of 10 mm, a length of 12.5 mm, and a rating. Ten aluminum electrolytic capacitors each having a voltage of 50 V and a capacitance of 150 μF were manufactured and subjected to aging treatment.
These products were applied in a constant temperature bath at 105 ° C. for a rated voltage of 3000 hours, and the capacitance change rate and tan δ relative to the initial values were measured. The results shown in Table 2 were obtained.
[0013]
[Table 2]

[0014]
From Table 2, it can be seen that the example in which poly-N-vinylcarbazole is dissolved has an excellent effect in that the decrease in capacity and the increase in tan δ are suppressed as compared with the conventional example.
[0015]
Note that when the amount of poly-N-vinylcarbazole dissolved is 0.05 wt%, the effect of suppressing the increase in tan δ is not sufficient for applications that require long-term reliability. Therefore, the amount of poly-N-vinylcarbazole dissolved is preferably in the range of 0.10 to 2.00 wt%.
[0016]
Further, the effect of poly-N-vinylcarbazole is not limited to the examples, and an electrolyte solution obtained by dissolving the above-described compounds alone or in combination thereof has the same effects as the examples.
[0017]
【The invention's effect】
As described above, an electrolytic capacitor using an electrolytic solution in which an organic carboxylic acid or a salt thereof and poly-N-vinylcarbazole are dissolved in a mixed solvent of ethylene glycol and water according to the present invention has a capacitance higher than that of a conventional capacitor. Reduction and increase in tan δ can be suppressed, and long-term reliability can be improved.

Claims (2)

An organic carboxylic acid or a salt thereof and poly-N-vinylcarbazole (Chemical Formula 1) are dissolved in a mixed solvent of ethylene glycol and water ,
An electrolytic solution for driving an electrolytic capacitor, wherein the amount of poly-N-vinylcarbazole dissolved is 0.1 to 5.0 wt% .

An electrolytic solution for driving an electrolytic capacitor, wherein the amount of poly-N-vinylcarbazole according to claim 1 is 2.0 wt% or less .