JP6422165B2 - Electrolytic solution for electrolytic capacitor drive - Google Patents

Description

  The present invention relates to an electrolytic solution for driving an electrolytic capacitor, and more particularly to an electrolytic solution for driving an aluminum electrolytic capacitor for medium to high pressure.

  Conventionally, as a driving electrolytic solution for an aluminum electrolytic capacitor for medium and high pressure, an electrolytic solution in which boric acid or a salt thereof is added to ethylene glycol or the like as a main solvent has been used. However, boric acid easily undergoes an esterification reaction with ethylene glycol or the like as a main solvent at a high temperature of 85 ° C. or higher to produce a large amount of water. For this reason, the aluminum oxide film, which is a dielectric material, is significantly hydrated and deteriorated, and due to its high vapor pressure, the explosion-proof valve opens and the outer case is deformed. Was the cause of shortening. Then, the electrolyte solution containing aliphatic dicarboxylic acid, such as adipic acid and sebacic acid, or its salt has been used (nonpatent literature 1).

  However, although dicarboxylic acids such as adipic acid and sebacic acid have high electrical conductivity, they are poorly soluble in ethylene glycol, which is a main solvent, so the amount added to the electrolyte must be kept low. As a result, there is a problem that the electrical conductivity of the electrolytic solution becomes small, and deterioration with time such as a decrease in electrical conductivity is large under high temperature conditions, and satisfactory capacitor characteristics cannot be obtained.

  On the other hand, an aromatic monocarboxylic acid in which a carboxylic acid is directly substituted on a benzene ring, such as benzoic acid and substituted benzoic acid, has the advantage of being highly stable under high temperature conditions and mitigating deterioration over time. There is a problem that not only the chemical conversion is lowered but also satisfactory conductivity and withstand voltage cannot be obtained simultaneously (Patent Document 1 and Patent Document 2).

Japanese Unexamined Patent Publication No. 2002-373833 Japanese Unexamined Patent Publication No. 2013-149638

“Electrolyte cathode aluminum electrolytic capacitor” (published by Nihon Denki Kogyo Kogyo Co., Ltd., 1997) pages 387-402

  As described above, various studies have been made so far, but an electrolyte for driving an aluminum electrolytic capacitor for medium- and high-voltages satisfying withstand voltage characteristics, high-temperature and long-life characteristics, and capacitor productivity has been obtained. Absent.

  In order to solve the above-described problems, the present invention provides an electrolytic solution for driving an electrolytic capacitor having excellent withstand voltage characteristics, high temperature and long life characteristics, and high productivity of a capacitor, in particular, an electrolytic solution for driving a medium-high voltage aluminum electrolytic capacitor. The purpose is to provide a liquid.

  The inventors of the present invention have intensively studied to achieve the above-mentioned problems, and have reached the present invention having the following summary.

（Ｚは、式（ＩＩＩ）で表わされる基であり、Ｒ_１、Ｒ_２は、それぞれ独立して、直鎖若しくは分岐の炭素数１〜２０のアルキレン基である。Ｘ¹〜Ｘ⁵は、それぞれ独立に、水素原子、アルキル基、アルケニル基、アラルキル基、アリール基、アルコキシ基、カルボキシル基、アシル基、式（ＩＩ）又は式（ＩＩＩ）で表わされる基であり、かつＸ ¹ 〜Ｘ ⁵ のうちの少なくとも一つが、式（ＩＩ）、式（ＩＩＩ）又はカルボキシル基である。）
（３）前記化合物が、下記式（IV）又は式（Ｖ）で表される、上記（１）又は上記（２）に記載の電解コンデンサ駆動用電解液。

（Ｒ_３、Ｒ_４、Ｒ_５は、それぞれ独立して、炭素数１〜２０のアルキレン基であり、Ｘは、水素、又は分岐してもよく置換されていてもよい炭素数１〜１０のアルキル基若しくはアルコキシ基、シクロアルキル基、又はアリール基であり、ｎは１〜４である。）
（４）前記化合物の塩が、アンモニウム塩、第１級〜第４級アミン塩、アルカリ金属塩又は、含窒素複素環式化合物塩である、上記（１）〜（３）のいずれか１項に記載の電解コンデンサ駆動用電解液。
（５）前記化合物の塩を、電解液中に、０．１〜２０．０重量％含有する、上記（１）〜（４）のいずれか１項に記載の電解コンデンサ駆動用電解液。
（６）前記有機溶媒が、多価アルコール、又は多価アルコールのモノ若しくはジアルキルエーテルを主溶媒とする、上記（１）〜（５）のいずれか１項に記載の電解コンデンサの駆動用電解液。
（７）電解液が、１０重量％以下の水分含有量を有する、上記（１）〜（６）のいずれか１項に記載のアルミニウム電解コンデンサの駆動用電解液。
（８）耐電圧が１６０〜５００Vの中高圧用のルミニウム電解コンデンサである、上記（１）〜（７）のいずれか１項に記載のアルミニウム電解コンデンサの駆動用電解液。
(1) at least two groups having a benzene ring or a naphthalene ring substituted a carboxyl group, and substituted on the benzene ring or a naphthalene ring at least one group including the mosquito carboxyl groups via an oxygen radicals An electrolytic solution for driving an electrolytic capacitor, wherein the salt of the compound is dissolved in an organic solvent.
(2) The electrolytic solution for driving an electrolytic capacitor according to the above (1), wherein the compound is a compound represented by the following formula (I).

(Z is a group represented by the formula (III), and R ₁ and R ₂ are each independently a linear or branched alkylene group having 1 to 20 carbon atoms. X ^{1 to} X ⁵ are Each independently a hydrogen atom, an alkyl group, an alkenyl group, an aralkyl group, an aryl group, an alkoxy group, a carboxyl group, an acyl group, a group represented by formula (II) or formula (III), and X ^{1 to} X ⁵ Is at least one of formula (II), formula (III) or a carboxyl group.
(3) before asked compound is represented by the following formula (IV) or Formula (V), at the (1) or an electrolytic capacitor driving electrolyte according to the above (2).

(R ₃ , R ₄ and R ₅ are each independently an alkylene group having 1 to 20 carbon atoms, and X is hydrogen or a branched or substituted carbon atom having 1 to 10 carbon atoms. An alkyl group, an alkoxy group, a cycloalkyl group, or an aryl group, and n is 1 to 4.)
(4) salts of previous ineffective compounds are ammonium salts, primary to quaternary amine salts, alkali metal salts or a nitrogen-containing heterocyclic compound salt, any of the above (1) to (3) 2. An electrolytic solution for driving an electrolytic capacitor according to item 1.
(5) a salt of pre hear compounds, in the electrolytic solution contains 0.1 to 20.0 wt%, the above (1) to (4) electrolytic capacitors driving electrolyte according to any one of liquid.
(6) The electrolytic solution for driving an electrolytic capacitor according to any one of (1) to ( 5) , wherein the organic solvent is a polyhydric alcohol, or a mono- or dialkyl ether of a polyhydric alcohol as a main solvent. .
(7) The electrolytic solution for driving an aluminum electrolytic capacitor according to any one of (1) to ( 6) , wherein the electrolytic solution has a water content of 10% by weight or less.
(8) The electrolytic solution for driving an aluminum electrolytic capacitor according to any one of the above (1) to ( 7) , which is a medium-high voltage luminium electrolytic capacitor having a withstand voltage of 160 to 500V.

  According to the present invention, a novel electrolytic solution for driving an electrolytic capacitor, which is excellent in withstand voltage and high temperature life characteristics, has a short time (formation time) for forming an oxide film, and has high productivity of a capacitor. An electrolytic solution for driving an aluminum electrolytic capacitor for high pressure is provided.

The electrolytic solution for driving an electrolytic capacitor of the present invention is a compound having a benzene ring in which at least one group containing a carboxyl group is substituted, and the group containing the carboxyl group is bonded to the benzene ring via a carbon atom or an oxygen atom. A salt composed of a substituted compound (hereinafter also referred to as a specific aromatic carboxylic acid) and a base component is dissolved as a solute in an organic solvent.
The specific aromatic carboxylic acid in the present invention is preferably a compound represented by the above formula (I). In the above formula (I), Z is a carboxyalkyl group represented by the above formula (II) or a carboxyalkyloxy group represented by the above formula (III). R ₁ and R ₂ in formulas (II) and (III) are each independently an alkylene group having 1 to 20 carbon atoms, preferably 2 to 15 carbon atoms, particularly preferably 3 to 11 carbon atoms. The alkylene group may be linear or branched, and the hydrogen atom may be substituted.
Specific examples of the specific aromatic carboxylic acid in the present invention include p-tolylacetic acid, 2-phenylbutyric acid, and 1,4-phenylene in addition to the aromatic carboxylic acids exemplified in Tables 1-1 to 1-6 of Examples. Examples include diacetic acid and 2- (4-isobutylphenyl) propionic acid.

The substituents X ^{1 to} X ^{5 in} formula (I) are hydrogen or an optionally substituted linear or branched alkyl group having 1 to 20 carbon atoms, preferably 1 to 15 carbon atoms, cycloalkyl A group, an alkenyl group, an aralkyl group, an aryl group, an alkoxy group, a carboxyl group, a carboxyalkyl group represented by the above formula (II), a carboxyalkyloxy group represented by the above formula (III), a carboxyaryl group, or an acyl group. is there. Among these, an alkyl group, an alkoxy group, a carboxyl group, a carboxyalkyl group represented by the above formula (II), or a carboxyalkyloxy group represented by the above formula (III) is preferable.
The number of X ^{1 to} X ⁵ is preferably 1 to 5, more preferably 1 to 3. Furthermore, one of them is preferably a carboxyl group, a carboxyalkyl group represented by the above formula (II), or a carboxyalkyloxy group represented by the above formula (III).

The specific aromatic ring carboxylic acid in the present invention is a compound having a benzene ring in which two groups including a carboxyl group are substituted, and one or both of the two groups are bonded to the benzene ring via an oxygen atom. Substituted compounds are preferred. Here, at least two groups containing a carboxyl group substituted on the benzene ring may be 3 to 5 as necessary.
The specific aromatic carboxylic acid having two groups containing such a carboxyl group is preferably a compound represented by the above formula (IV) or formula (V).

In the above formula (IV) and formula (V), R ₃ , R ₄ and R ₅ each independently represent 1 to 20 carbon atoms, preferably 2 to 15 carbon atoms, particularly preferably 3 to 3 carbon atoms. 11 alkylene groups. The alkylene group may be branched and the hydrogen atom may be substituted. X is hydrogen or an alkyl group, an alkoxy group, a cycloalkyl group, or an aryl group having 1 to 10 carbon atoms, preferably 1 to 4 carbon atoms, which may be branched or substituted. Among these, an alkyl group or an alkoxy group is preferable, and n is 1 to 4, preferably 1 or 2.

Preferred specific examples of the compound represented by the above formula (IV) or formula (V) are as follows: R ₃ , R ₄ and R ₅ are each an alkyl group having 1 to 12 carbon atoms, and the substituent X is a methyl group. , Ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, tertiary butyl group, methoxy group, ethoxy group, propoxy group, isopropoxy group, butoxy group, isobutoxy group, tertiary butoxy group, formyl group, acetyl group , A propionyl group or a benzoyl group.

  Further, preferred specific examples of the salt of the compound represented by the formula (IV) or the formula (V) are ammonium salts, primary, secondary, tertiary or quaternary of the compound of the preferred specific examples described above. An ammonium salt or an alkali metal salt. Of these, ammonium salts or primary, secondary, or tertiary ammonium salts are preferable, and ammonium salts are particularly preferable.

The base component in the present invention is preferably an ammonium salt, primary, secondary, tertiary or quaternary amine salt, nitrogen-containing heterocyclic compound salt, or alkali metal together with the specific aromatic carboxylic acid. Examples include base compounds that form salts.
These basic compounds include ammonia, primary, secondary, tertiary or quaternary amines depending on the type of salt of the specific aromatic carboxylic acid.
Preferred examples of the primary, secondary or tertiary ammonium salt include monoethylammonium salt, diethylammonium salt, dimethylammonium salt, dimethylethylammonium salt, triethylammonium salt, tributylammonium salt and triisobutylammonium salt. And triethanolammonium salt.
Preferred examples of the quaternary ammonium salt include tetramethylammonium salt, trimethylethylammonium salt, N-methylpyrrolidinium salt, N-ethylpyrrolidinium salt and the like.
Examples of the nitrogen-containing heterocyclic compound salt include 1,2,3,4-tetramethylimidazolinium salt, 2-ethyl-1,3,4-trimethylimidazolinium salt, 1-ethyl-2,3-dimethyl. Examples include imidazolinium salts.
Examples of the alkali metal salt include sodium salt and potassium salt.
Of these, ammonium salts or primary, secondary, or tertiary amine salts are preferable, and ammonium salts or dimethylamine salts are particularly preferable.

Examples of the organic solvent used in the electrolytic solution of the present invention include monohydric alcohols such as methanol and ethanol; polyhydric alcohols such as ethylene glycol, diethylene glycol, triethylene glycol, glycerin, 1,4-butanediol, and polyethylene glycol; diethylene glycol Mono- or dialkyl ether ethyl alcohols of polyhydric alcohols such as monomethyl ether, diethylene glycol monoethyl ether, polyethylene glycol monomethyl ether, polyethylene glycol monoethyl ether, polyethylene glycol dimethyl ether, triethylene glycol monomethyl ether, triethylene glycol dimethyl ether; N-methylformamide Amides such as N, N-dimethylformamide; γ-butyrolactone, γ-valerolac Cyclic esters such as ethylene; sulfur compounds such as dimethyl sulfoxide and sulfolane; carbonates such as propylene carbonate, ethylene carbonate, diethyl carbonate, styrene carbonate, dimethyl carbonate, and methyl ethyl carbonate; acetonitrile, butyronitrile, succinonitrile, glutaronitrile, Nitriles such as adiponitrile; Furans such as tetrahydrofuran and dioxane; and the like.
Of these, polyhydric alcohols or mono- or dialkyl ethers of polyhydric alcohols are preferred, and the polyhydric alcohols are particularly preferably ethylene glycol, diethylene glycol, glycerin, or polyethylene glycol.
The mono- or dialkyl ether of the polyhydric alcohol is preferably diethylene glycol monomethyl ether or diethylene glycol dimethyl ether. These are preferably 50% by weight or more, particularly 70% by weight or more of an organic solvent, and 100% by weight. May be.
In the present invention, these organic solvents may be used as a mixture of two or more in order to improve the solubility of solute, conductivity, temperature characteristics, and the like.

The electrolytic solution for driving a capacitor of the present invention can be obtained by preparing the salt of the specific aromatic carboxylic acid in advance and dissolving it in the organic solvent. Moreover, it can also obtain by making the raw material or precursor component which forms the said salt of the specific aromatic carboxylic acid add or react simultaneously in an organic solvent. In the electrolytic solution for driving a capacitor of the present invention, a specific aromatic carboxylic acid may be present together with the salt of the specific aromatic carboxylic acid.
For example, the target electrolyte solution of the present invention can be obtained by adding and reacting the specific aromatic carboxylic acid and ammonia or an amine compound in an organic solvent. Moreover, when obtaining the electrolytic solution for driving a capacitor of the present invention, means for accelerating dissolution such as heating and stirring and obtaining a uniform solution can be applied as necessary.

  In this case, the free aromatic carboxylic acid in the electrolyte solution according to the addition ratio of the specific aromatic carboxylic acid and the base ammonia, primary to tertiary amine, quaternary ammonium hydroxide or alkali hydroxide. It is preferable to control the abundance ratio of the carboxylic acid salt. Usually, it is preferable that the equivalent of the free aromatic carboxylic acid and the equivalent of the base are approximately equal. As a result, it is preferable that the specific aromatic carboxylic acid is a salt and the electrolytic solution does not contain a free carboxylic acid. The abundance ratio of the free carboxylic acid and the carboxylate can be determined by controlling the pH of the obtained electrolyte. The pH of the electrolytic solution is preferably 2 to 10, and more preferably 3 to 8.

  The content of the salt of the specific aromatic carboxylic acid in the electrolytic solution for driving a capacitor of the present invention is preferably 0.1 to 20% by weight. In the case of such a content, an electrolytic solution having a long service life at a high temperature can be obtained without increasing the electrical conductivity without increasing the withstand voltage and withstanding a wide range of use temperatures. It is not preferable that the content exceeds 20% by weight because of solubility or the like. Among these, the content of the salt of the specific aromatic carboxylic acid is more preferably 1 to 15% by weight, and particularly preferably 1 to 10% by weight.

  The capacitor driving electrolyte of the present invention may contain a small amount of water. The water content of the electrolytic solution may be, for example, in the range of 0.1 to 90% by weight. In particular, in the case of the medium and high voltage aluminum electrolytic capacitor of the present invention, the water content is desirably 10% by weight or less. When the amount of water exceeds 10% by weight, the defect rate and the explosion-proof valve operating rate increase. In this case, the water content in the electrolytic solution is more preferably 5% by weight or less.

In addition to the specific aromatic carboxylic acid or a salt thereof, a known electrolyte used for a normal capacitor driving electrolyte can be added to the capacitor driving electrolyte of the present invention. Examples of such electrolytes include organic acids such as organic carboxylic acids or salts thereof, inorganic acids or salts thereof, and the like. These electrolytes may be used alone or in combination of two or more.
Organic acids such as organic carboxylic acids include oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, nonanedicarboxylic acid, decanedicarboxylic acid, undecanedicarboxylic acid, dodecanedicarboxylic acid Aliphatic linear dicarboxylic acids such as acid and tridecanedicarboxylic acid; 3-methyladipic acid, 2-hexyladipic acid, 2-methylazeleic acid, 1,6-decanedicarboxylic acid, 5,6-decanedicarboxylic acid, etc. Aliphatic side chain dicarboxylic acids; monocarboxylic acids such as formic acid, acetic acid, nonanoic acid and heptanoic acid; unsaturated dicarboxylic acids such as maleic acid, fumaric acid, citraconic acid, itaconic acid and mesaconic acid; benzoic acid, methylbenzoic acid, Ethyl benzoic acid, dimethyl benzoic acid, diethyl benzoic acid, t-butyl benzoic acid, salicylic acid, methyl Aromatic carboxylic acids such as rusalicylic acid; aromatic dicarboxylic acids such as phthalic acid, isophthalic acid and terephthalic acid; borodi salts such as borodisalicylic acid, borodiglycolic acid, borodiphthalic acid and borodisoxalic acid;
Examples of the inorganic acid include boric acid, phosphoric acid, phosphorous acid, diphosphorous acid, polyphosphoric acid, silicic acid, and tungstic acid. Moreover, in the inorganic acid more than bivalence, the acid which partially esterified such as monoethyl phosphate and dibutyl phosphate can also be used.

Examples of the salt of the organic acid or inorganic acid include various salts. For example, in addition to ammonium salt, monoethylammonium salt, diethylammonium salt, dimethylammonium salt, dimethylethylammonium salt, triethylammonium salt, tributylammonium salt, triisobutylammonium salt, triethanolammonium salt and the like are preferable examples. . Preferred examples of the quaternary ammonium salt include tetramethylammonium salt, trimethylethylammonium salt, N-methylpyrrolidinium salt, N-ethylpyrrolidinium salt and the like. Examples of the nitrogen-containing heterocyclic compound salt include 1,2,3,4-tetramethylimidazolinium salt, 2-ethyl-1,3,4-trimethylimidazolinium salt, 1-ethyl-2,3-dimethyl. Examples of the alkali metal salt, such as imidazolinium salt, include sodium salt and potassium salt.
As the base component of the salt, those similar to the base component used in the specific aromatic carboxylic acid can be used.
In the capacitor driving electrolyte of the present invention, the base component used for forming the salt of the organic acid or inorganic acid may be the same base component as the aromatic carboxylic acid or a different base component.

Moreover, various additives can be contained for the purpose of protecting the oxide film, improving the pressure resistance, improving the chemical conversion, and improving the life characteristics. Examples of additives include polyhydric alcohols such as mannitol and sorbitol, polymer compounds such as polyvinyl alcohol and polyethylene glycol, inorganic fine particles such as silica and alumina, and nitrogen-containing organic compounds such as ethylenediaminetetraacetic acid and urea. It is done.
These can be used as a simple substance, but it is also possible to use an acid ester or complex as an electrolyte or additive.
The additive amount of these additives is preferably 0.01 to 10% by weight, more preferably 0.05 to 5% by weight, as an additive alone.

  One or more aromatic nitro compounds can be added for the purpose of suppressing an increase in internal pressure due to hydrogen gas generated inside the capacitor. Examples of such aromatic nitro compounds include nitroanisole, nitrotoluene, nitrocresol, nitrophenylacetic acid, nitroacetanilide, nitrobenzyl alcohol, nitroacetophenone, nitroaniline, nitrophenol, nitrobenzoic acid, methylnitrobenzoic acid, nitrocumene, nitroterephthale Examples include acids, nitroisophthalic acid, nitrophenetole and the like. Of these, nitroanisole, nitrobenzyl alcohol, nitroacetophenone, nitroacetanilide, nitrobenzoic acid, or nitrophenol is preferable. Even if these are added as a simple substance, a sufficient effect can be obtained. However, if necessary, a higher effect can be obtained by adding an unsaturated carbonyl compound such as dimethyl maleate. The addition amount of the aromatic nitro compound is preferably 0.01 to 10% by weight, and more preferably 0.5 to 5% by weight.

The electrolytic solution for driving a capacitor of the present invention can be used for various electrolytic capacitors, and is particularly useful as a driving solution for an aluminum electrolytic capacitor for medium to high pressure. In the present invention, the medium and high voltage aluminum electrolytic capacitor means an aluminum electrolytic capacitor having a rated voltage (withstand voltage) of 160 to 500V, preferably 300 to 500V.
The electrolytic solution for driving a capacitor of the present invention is suitable as a driving fluid for electrolytic capacitors having a rated voltage of 350 to 500V, and is particularly useful as a driving fluid for electrolytic capacitors for high voltage having a rated voltage of 400 to 500V.
The shape of the electrolytic capacitor using the electrolytic solution for driving a capacitor of the present invention is not particularly limited, and may be any of a screw terminal type, a substrate self-standing type, and a lead type.
There is no restriction | limiting in particular also in the rated capacitance range of an electrolytic capacitor, the range of 0.1-47000 micro F can be illustrated, and the range of 30-30000 micro F is preferable.

  EXAMPLES Hereinafter, the present invention will be described more specifically based on examples, but the present invention is not construed as being limited to the following examples.

Example 1
Into a glass container, 4.6 parts of a specific aromatic carboxylic acid (A-1) was added to 95 parts of ethylene glycol, and 0.4 part of ammonia gas was blown into the glass container while stirring at 20 to 30 ° C. The electrolyte solution having a salt concentration of 5% by weight was prepared by continuing the stirring for about 1 hour. Further, the amount of ammonia gas blown can be calculated by measuring the weight of the electrolyte before and after blowing.

Examples 2-16 and 19-38
In Example 1, instead of the specific aromatic carboxylic acid (A-1), the specific aromatic carboxylic acids (A-2) to (A-16) and (A-19) to (A-38) were used. The same operations as in Example 1 were performed to obtain the electrolyte solutions of the present invention in Examples 2 to 16 and 19 to 38.

Example 17
The same operation as in Example 1 was performed except that the specific aromatic carboxylic acid (A-3) was replaced with diethylamine as the base in place of the specific aromatic carboxylic acid (A-1) in Example 1, and Example 17 The electrolytic solution of the present invention was obtained.

Example 18
Example 18 was carried out in the same manner as in Example 1, except that the specific aromatic carboxylic acid (A-3) was replaced with propylene glycol instead of the specific aromatic carboxylic acid (A-1) in Example 1. The electrolyte solution of the present invention was obtained.

Example 39
Example 39 was carried out in the same manner as in Example 1 except that the specific aromatic carboxylic acid (A-19) was replaced with dimethylamine instead of the specific aromatic carboxylic acid (A-1) in Example 1. The electrolyte solution of the present invention was obtained.

Example 40
The same operation as in Example 1 was carried out except that the specific aromatic carboxylic acid (A-19) was replaced by triisobutylamine instead of the specific aromatic carboxylic acid (A-1) in Example 1. Forty electrolyte solutions of the present invention were obtained.

Example 41
In Example 1, the specific aromatic carboxylic acid (A-19) was used instead of the specific aromatic carboxylic acid (A-1), and the solvent was changed to a mixed solvent in which the ratio of ethylene glycol to diethylene glycol was 3: 1. 1 was obtained, and the electrolytic solution of the present invention of Example 41 was obtained.

Example 42
The same operation as in Example 1 was performed except that the specific aromatic carboxylic acid (A-26) was used instead of the specific aromatic carboxylic acid (A-1) in Example 1, the base was dimethylamine, and the solvent was diethylene glycol. Thus, an electrolytic solution of the present invention of Example 42 was obtained.

Comparative Examples 1-3
Comparative Example 1-3 was performed in the same manner as in Example 1 except that sebacic acid, 1,6-decanedicarboxylic acid and benzoic acid were used instead of the specific aromatic carboxylic acid (A-1) in Example 1. An electrolyte solution was obtained.

  Using the electrolytic solutions of Examples 1 to 42 and Comparative Examples 1 to 3, spark generation voltage, electrical conductivity, chemical formation time, and electrical conductivity retention after 1000 hours were measured by the following methods. The results are shown in Tables 2-1 and 2-2.

<Spark generation voltage, formation time>
Measures sparking voltage when a constant current with a current density of 0.25 mA / cm2 is applied at 105 ° C using AD 752E, chemical etching etched aluminum foil for the anode and plain aluminum foil for the cathode. did.
The formation time (time for forming the aluminum oxide film) is a value obtained by calculating the rising voltage per minute when measuring the spark generation voltage, and was calculated by the following method.
Formation time (V / min) = (spark generation voltage) / (time to reach spark generation voltage)

<Conductivity, conductivity maintenance rate>
CM-30R manufactured by Toa DKK Co., Ltd. was used, and the conductivity was measured while keeping the temperature constant in a 30 ° C. constant temperature bath. Thereafter, the electrolytic solution was stored in a thermostatic bath at 105 ° C. for 1000 hours, and the conductivity after storage was measured in the same manner. Moreover, the electrical conductivity maintenance factor was computed with the following method.
Conductivity maintenance rate (%) = 100 × {(Conductivity after high temperature storage) / (Conductivity before high temperature storage)}

  As is clear from Tables 2-1 and 2-2, it can be seen that the electrolytes of Examples 1 to 42 have a high spark generation voltage and also have high thermal stability and chemical conversion. . Moreover, the same tendency is shown even if a salt is a tertiary amine salt, a quaternary amine salt, an alkali metal salt, and a nitrogen-containing heterocyclic compound salt.

  Moreover, the electrical conductivity and the spark generation voltage at the three salt concentrations of the electrolytic solution of Example 3 were measured. The results are shown in Table 3.

  As is apparent from Table 3, it can be seen that high spark generation voltage and electrical conductivity can be obtained even when the salt concentration of the specific aromatic carboxylic acid is changed.

The electrolytic solution for driving a capacitor of the present invention can be used for various electrolytic capacitors, and is particularly useful as a driving solution for an aluminum electrolytic capacitor for medium to high pressure.
The entire contents of the specification, claims, and abstract of Japanese Patent Application No. 2014-013735 filed on January 28, 2014 are incorporated herein as the disclosure of the specification of the present invention. Is.

Claims (8)

Has a benzene ring or a naphthalene ring in which at least two groups are substituted include a carboxyl group, and at least one group including the mosquito carboxyl group is substituted on the benzene ring or naphthalene ring via an oxygen radicals An electrolytic solution for driving an electrolytic capacitor, wherein a salt of the compound is dissolved in an organic solvent. The electrolytic solution for driving an electrolytic capacitor according to claim 1, wherein the compound is a compound represented by the following formula (I).

(Z is a group represented by the formula (III), and R ₁ and R ₂ are each independently a linear or branched alkylene group having 1 to 20 carbon atoms. X ^{1 to} X ⁵ are Each independently a hydrogen atom, an alkyl group, an alkenyl group, an aralkyl group, an aryl group, an alkoxy group, a carboxyl group, an acyl group, a group represented by formula (II) or formula (III), and X ^{1 to} X ⁵ Is at least one of formula (II), formula (III) or a carboxyl group. Before hear compound is represented by the following formula (IV) or Formula (V), at an electrolytic capacitor driving electrolyte according to claim 1 or 2.

(R ₃ , R ₄ and R ₅ are each independently an alkylene group having 1 to 20 carbon atoms, and X is hydrogen or a branched or substituted carbon atom having 1 to 10 carbon atoms. An alkyl group, an alkoxy group, a cycloalkyl group, or an aryl group, and n is 1 to 4.) Salts of pre hear compounds are ammonium salts, primary to quaternary amine salts, alkali metal salts or a nitrogen-containing heterocyclic compound salt, according to any one of claims 1 to 3 Electrolytic solution for electrolytic capacitor drive. The salt of pre hear compounds, in the electrolytic solution contains 0.1 to 20.0 wt%, electrolytic capacitor driving electrolyte according to any one of claims 1-4. The electrolytic solution for driving an electrolytic capacitor according to any one of claims 1 to 5 , wherein the organic solvent contains a polyhydric alcohol or a mono- or dialkyl ether of a polyhydric alcohol as a main solvent. The electrolytic solution for driving an aluminum electrolytic capacitor according to any one of claims 1 to 6 , wherein the electrolytic solution has a water content of 10% by weight or less. The electrolytic solution for driving an aluminum electrolytic capacitor according to any one of claims 1 to 7 , wherein the electrolytic solution is a luminium electrolytic capacitor for medium to high voltage with a withstand voltage of 160 to 500V.