JP2013102004A - Gel electrolytic solution for electrolytic capacitor and electrolytic capacitor - Google Patents

Abstract

Disclosed is a gel electrolyte for an electrolytic capacitor having high conductivity and spark voltage and excellent durability, and an electrolytic capacitor using the same.
A polymer of colloidal silica, an electrolyte salt comprising a carboxylic acid component (A) and any one of base components (B) represented by the general formulas (1) to (7), and an organic solvent. A gel electrolyte solution for an electrolytic capacitor, wherein the colloidal silica polymer is a polymer polymerized using acidic colloidal silica or ammonia-stabilized colloidal silica, and The electrolytic capacitor used.
[Selection figure] None

Description

  The present invention relates to a gel electrolyte for electrolytic capacitors having high conductivity and spark voltage and excellent long-term stability, and an electrolytic capacitor using the same.

  As an electrolytic solution for an electrolytic capacitor in the past, a solution obtained by dissolving an organic acid, an inorganic acid, or a salt thereof as an electrolyte in a solvent such as γ-butyrolactone having a low viscosity at a low temperature is used. For example, an electrolyte made of a salt of a tetraalkylammonium such as tetramethylammonium and a dicarboxylic acid such as maleic acid or phthalic acid is dissolved in a solvent such as γ-butyrolactone or ethylene glycol.

  Among electrolytic solutions, the electrical conductivity is directly related to the loss of the electrolytic capacitor, impedance characteristics, etc., and therefore, electrolytic solutions for electrolytic capacitors having high electrical conductivity have been actively developed. Among these, a quaternary ammonium salt having a carboxylic acid as an anion as a solute salt has attracted attention because it can obtain high electrical conductivity (Patent Document 1).

  Examples of the organic solvent used in the electrolytic solution include γ-butyrolactone and a mixed solvent of γ-butyrolactone and ethylene glycol, both of which have excellent initial conductivity, but immediately decrease when used. Therefore, there was a problem inferior in durability (Patent Document 2).

  An electrolytic solution having high conductivity has generally been used in a region where the spark voltage of the electrolytic solution itself is low and the rated voltage is 50 V or less. In order to improve the spark voltage, there is also an electrolytic solution for electrolytic capacitors containing colloidal silica. However, since the colloidal silica is only dispersed in the electrolytic solution, the spark voltage cannot be sufficiently obtained and durability (Patent document 3).

  As described above, there is a demand for an electrolytic capacitor having high conductivity and spark voltage and excellent durability.

Japanese Patent Laid-Open No. 3-6646 JP-A-6-196366 JP 2007-273922 A

  An object of the present invention is to provide a gel electrolyte for electrolytic capacitors having high conductivity and spark voltage and excellent durability, and an electrolytic capacitor using the same.

The present invention comprises a colloidal silica polymer, an electrolyte salt comprising a carboxylic acid component (A) and any one of the basic components (B) represented by the general formulas (1) to (7), and an organic solvent. In the gel electrolyte solution for electrolytic capacitors contained,
A gel electrolyte for an electrolytic capacitor, wherein the colloidal silica polymer is a polymer polymerized using acidic colloidal silica or ammonia-stabilized colloidal silica.

  That is, the present invention is as follows.

The first invention is a colloidal silica polymer, an electrolyte salt comprising a carboxylic acid component (A) and any of the base components (B) represented by the following general formulas (1) to (7), an organic solvent In the gel electrolyte solution for electrolytic capacitors containing,
A gel electrolyte for an electrolytic capacitor, characterized in that the polymer of colloidal silica is a polymer obtained by polymerization using acidic colloidal silica or ammonia-stabilized colloidal silica.

（式（１）〜（７）中、Ｒ_１〜Ｒ_３０は、それぞれ同一でも異なっても良い水素、炭素数１〜１８のアルキル基、炭素数１〜１８のアルコキシ基、水酸基であり、隣接Ｒ同士は連結し、炭素数２〜６のアルキレン基を形成しても良い。）

(In the formulas (1) to (7), R _{1 to} R ₃₀ are the same or different hydrogen, a C 1-18 alkyl group, a C 1-18 alkoxy group, and a hydroxyl group, and adjacent to each other. Rs may be linked together to form an alkylene group having 2 to 6 carbon atoms.)

  The second invention is characterized in that the carboxylic acid component (A) is one selected from the group consisting of phthalic acid, maleic acid, salicylic acid, benzoic acid, azelaic acid, sebacic acid, and 1,6-decanedicarboxylic acid. It is the gel electrolyte solution for electrolytic capacitors as described in 1st invention to do.

  3rd invention is the gel electrolyte solution for electrolytic capacitors as described in 1st or 2nd invention, wherein the average particle diameters of acidic colloidal silica or ammonia stable type colloidal silica are 1-50 nm.

  According to a fourth aspect of the invention, in any one of the first to third aspects, the content of the colloidal silica polymer in the gel electrolyte for an electrolytic capacitor is 1.0 to 50% by mass. This is a gel electrolyte for electrolytic capacitors.

  A fifth invention is an electrolytic capacitor comprising the gel electrolytic solution for an electrolytic capacitor according to any one of the first to fourth inventions.

  According to the present invention, it is possible to obtain a gel electrolyte solution for an electrolytic capacitor having high conductivity and spark voltage and excellent durability, and an electrolytic capacitor using the same.

  The gel electrolyte solution for electrolytic capacitors of the present invention will be described.

  As a result of intensive studies, the present inventors have found that a colloidal silica polymer, an electrolyte salt comprising a carboxylic acid component (A) and any one of the basic components (B) represented by the general formulas (1) to (7), In an electrolytic capacitor gel electrolyte containing an organic solvent, the colloidal silica polymer is a polymer polymerized using acidic colloidal silica or ammonia-stabilized colloidal silica. The present inventors have found that a gel electrolytic solution and a solid electrolytic capacitor using the same can solve the above problems, and have reached the present invention.

<Colloidal silica>
Colloidal silica is a colloid of SiO ₂ or its hydrate, and has a particle size of 1 to 300 nm and no fixed structure. It can be obtained by dialysis after dilute hydrochloric acid is allowed to act on the silicate.

  Colloidal silica is hardly dissolved in water or an organic solvent, and can be used as a polymer obtained by adding to a liquid electrolyte as a colloidal solution generally dispersed in an appropriate dispersion solvent and polymerizing by applying heat.

  Colloidal silica is usually called sodium-stable colloidal silica, contains Na by production, and the surface of colloidal silica is ONa group. The sodium-stable colloidal silica does not exhibit sufficient dispersibility in an organic solvent, and sodium ions inhibit the conductivity and the spark voltage are not sufficiently improved.

The colloidal silica used in the present invention is acidic colloidal silica or ammonium stable colloidal silica.
Acidic colloidal silica is colloidal silica in which the surface of the colloidal silica is an OH group from which Na has been removed. Ammonia-stable colloidal silica is prepared by removing Na to form an OH group, and then treating the surface with ammonia. Colloidal silica stabilized with ammonia ions.

The gel electrolyte solution for electrolytic capacitors of the present invention is characterized by containing a polymer obtained by polymerizing acidic colloidal silica or ammonia-stable colloidal silica.
Since the colloidal silica contains a polymer in which silanol groups are polymerized, the electrolytic solution itself is in a gel form.

A method for producing a gel electrolyte solution for an electrolytic capacitor may be prepared by adding a polymer obtained by polymerizing colloidal silica to the electrolyte solution to produce a gel electrolyte solution, or heating and polymerizing the electrolyte solution containing colloidal silica. Thus, a gel electrolyte may be produced as a polymer.
Moreover, the electrolytic solution for electrolytic capacitors containing colloidal silica is usually heated at about 80 ° C. in order to distill off water, but at 80 ° C., the colloidal silica does not gel. By heating the electrolytic solution at 120 to 200 ° C., silanol groups of colloidal silica are polymerized and gelled.

  By containing a polymer of acidic colloidal silica or ammonia-stabilized colloidal silica in the electrolyte, the conductivity and spark voltage can be greatly improved.

  The content of the colloidal silica polymer in the electrolytic solution for electrolytic capacitors is 0.1 to 50% by mass, more preferably 0.5 to 40% by mass, and particularly preferably 1.0 to 30% by mass. Is mentioned. If the amount is less than 0.1% by mass, the effect of improving the electrical characteristics of the electrolytic capacitor is small.

  The average particle diameter of the colloidal silica may be any, preferably 1 to 50 nm, more preferably 1 to 30 nm. By setting the average particle size, it is possible to obtain a gel electrolyte solution for an electrolytic capacitor in which an electrolyte salt is uniformly dispersed when polymerized by being excellent in dispersibility in a solvent.

  The shape of the colloidal silica may be any of a spherical type, a chain type, and a cyclic type in which colloidal silica is aggregated in a ring and dispersed in a solvent.

  The pH of acidic colloidal silica is about pH 2-4, and the pH of ammonia-stable colloidal silica is about pH 9-11.

  Examples of commercially available ammonia-stable colloidal silica include Snowtex (registered trademark) N (manufactured by Nissan Chemical Industries, Ltd.), Ludox (registered trademark) AS (manufactured by W. Grace and Company-Connecticut). Nalco (registered trademark) 2326 (manufactured by Nalco Chemical Company), Adelite (registered trademark) AT-20N (manufactured by ADEKA), and the like.

  As commercially available acidic colloidal silica, Snowtex (registered trademark) O (manufactured by Nissan Chemical Industries, Ltd.), Nalco (registered trademark) 1034A (manufactured by Nalco Chemical Company), Cataloid (registered trademark) SN (catalytic chemistry) Kogyo Co., Ltd.), Adelite (registered trademark) AT-20Q (ADEKA), and the like.

<Electrolyte salt>
The electrolyte salt used for the gel electrolyte solution for electrolytic capacitors of the present invention is a salt composed of the carboxylic acid component (A) and the base component (B) represented by any one of the general formulas (1) to (7).

The carboxylic acid component (A) is an organic compound substituted with a carboxylic acid, and is an organic carboxylic acid such as an aromatic carboxylic acid or an aliphatic carboxylic acid. Specifically, for example, aromatic carboxylic acid: (for example, phthalic acid, salicylic acid, isophthalic acid, terephthalic acid, trimellitic acid, pyromellitic acid, benzoic acid, resorcinic acid, cinnamic acid, naphthoic acid, mandelic acid), Aliphatic carboxylic acids: ([saturated carboxylic acids such as oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecanedioic acid, dodecanedioic acid, tridecanedioic acid , Tetradecanedioic acid, pentadecanedioic acid, hexadecanedioic acid, 3-tert-butyladipic acid, methylmalonic acid, ethylmalonic acid, propylmalonic acid, butylmalonic acid, pentylmalonic acid, hexylmalonic acid, dimethylmalonic acid, diethyl Malonic acid, methylpropylmalonic acid, methylbutylmalonic acid, ethylpropyl Ronic acid, dipropylmalonic acid, methylsuccinic acid, ethylsuccinic acid, 2,2-dimethylsuccinic acid, 2,3-dimethylsuccinic acid, 2-methylglutaric acid, 3-methylglutaric acid, 3-methyl-3-ethylglutar Acid, 3,3-diethylglutaric acid, methylsuccinic acid, 2-methylglutaric acid, 3-methylglutaric acid, 3,3-dimethylglutaric acid, 3-methyladipic acid, 1,6-decanedicarboxylic acid, 5,6 -Decanedicarboxylic acid, formic acid, acetic acid, propionic acid, butyric acid, isobutyric acid, valeric acid, caproic acid, enanthic acid, caprylic acid, pelargonic acid, lauric acid, myristic acid, stearic acid, behenic acid, undecanoic acid, borodiglycol Acid, borodisuccinic acid, borodisalicylic acid, itaconic acid, tartaric acid, glycolic acid, lactic acid, pyruvic acid], [unsaturated Carboxylic acids such as maleic acid, fumaric acid, acrylic acid, methacrylic acid, oleic acid]) or the like. These may be used alone or in combination of two or more.
Among these, phthalic acid, maleic acid, salicylic acid, benzoic acid, azelaic acid, sebacic acid, and 1,6-decanedicarboxylic acid are preferable because they have high conductivity and are thermally stable.

Examples of the base component (B) include any compounds represented by the following general formulas (1) to (7).

In the compounds represented by the general formulas (1) to (7), R _{1 to} R ₃₀ may be the same or different, hydrogen, an alkyl group having 1 to 18 carbon atoms, an alkoxy group having 1 to 18 carbon atoms, It is a hydroxyl group, and adjacent Rs may be connected to form an alkylene group having 2 to 6 carbon atoms.

Specific examples of the base component represented by the general formula (1) include ammonium, tetramethylammonium, tetraethylammonium, tetrapropylammonium, tetraisopropylammonium, tetrabutylammonium, trimethylethylammonium, triethylmethylammonium, dimethyldiethylammonium, Dimethylethylmethoxyethylammonium, dimethylethylmethoxymethylammonium, dimethylethylethoxyethylammonium, trimethylpropylammonium, dimethylethylpropylammonium, triethylpropylammonium, spiro- (1,1 ')-bipyrrolidinium, piperidine-1-spiro-1' -Pyrrolidinium, spiro- (1,1 ')-bipiperidinium and the like.
Among these, ammonium, tetraethylammonium, and spiro- (1,1 ′)-bipyrrolidinium are particularly preferable because they have high conductivity and further improve the spark voltage.

Specific examples of the base component represented by the general formula (2) include trimethylamine, triethylamine, tripropylamine, triisopropylamine, tributylamine, diethylmethylamine, dimethylethylamine, diethylmethoxyamine, dimethylmethoxyamine, dimethylethoxyamine. , Diethylethoxyamine, methylethylmethoxyamine, N-methylpyrrolidine, N-ethylpyrrolidine, N-propylpyrrolidine, N-isopropylpyrrolidine, N-butylpyrrolidine, N-methylpiperidine, N-ethylpiperidine, N-propylpiperidine, N-isopropyl piperidine, N-butyl piperidine and the like can be mentioned.
Among these, trimethylamine, triethylamine, dimethylethylamine, diethylmethylamine, and N-methylpyrrolidine are particularly preferable because they have high conductivity and further improve the spark voltage.

Specific examples of the base component represented by the general formula (3) include dimethylamine, diethylamine, diisopropylamine, dipropylamine, dibutylamine, methylethylamine, methylpropylamine, methylisopropylamine, methylbutylamine, ethylisopropylamine, Examples include ethylpropylamine, ethylbutylamine, isopropylbutylamine, and pyrrolidine.
Among these, trimethylamine, triethylamine, dimethylamine, diethylamine, methylethylamine, and pyrrolidine are particularly preferable because they have high conductivity and further improve the spark voltage.

Specific examples of the base component represented by the general formula (4) include 1,3-dimethylimidazolium, 1,3-diethylimidazolium, 1,3-dipropylimidazolium, 1,3-diisopropylimidazolium, 1,3-dibutylimidazolium, 1-ethyl-3-methylimidazolium, 1-butyl-3-methylimidazolium, 1-butyl-3-ethylimidazolium, 1,2,3-trimethylimidazolium, 1, 2,3,4-tetramethylimidazolium, 1,3-dimethyl-2-ethylimidazolium, 1,2-dimethyl-3-ethyl-imidazolium, 1,2,3-triethylimidazolium, 1,2, Examples include 3,4-tetraethylimidazolium.
Among these, 1,3-dimethylimidazolium, 1,3-diethylimidazolium, 1-ethyl-3-methylimidazolium, 1-butyl- are preferred because they have high conductivity and further improve the spark voltage. Particularly preferred are 3-methylimidazolium and 1-butyl-3-ethylimidazolium.

Specific examples of the base component represented by the general formula (5) include 1,2,3,4-tetramethylimidazolinium, 1,3,4-trimethyl-2-ethylimidazolinium, 1,3- Dimethyl-2,4-diethylimidazolinium, 1,2-dimethyl-3,4-diethylimidazolinium, 1-methyl-2,3,4-triethylimidazolinium, 1,2,3,4-tetraethyl Imidazolinium, 1,2,3-trimethylimidazolinium, 1,3-dimethyl-2-ethylimidazolinium, 1-ethyl-2,3-dimethylimidazolinium, 1,2,3-triethylimidazoli Nium, 4-cyano-1,2,3-trimethylimidazolinium, 3-cyanomethyl-1,2-dimethylimidazolinium, 2-cyanomethyl-1,3-dimethylimidazole 4-acetyl-1,2,3-trimethylimidazolinium, 3-acetylmethyl-1,2-dimethylimidazolinium, 4-methylcarbooxymethyl-1,2,3-trimethylimidazolinium, 3 -Methylcarbooxymethyl-1,2-dimethylimidazolinium, 4-methoxy-1,2,3-trimethylimidazolinium, 3-methoxymethyl-1,2-dimethylimidazolinium, 4-formyl-1, 2,3-trimethylimidazolinium, 3-formylmethyl-1,2-dimethylimidazolinium, 3-hydroxyethyl-1,2-dimethylimidazolinium, 4-hydroxymethyl-1,2,3-trimethylimidazolo Examples thereof include linium and 2-hydroxyethyl-1,3-dimethylimidazolinium.
Among these, 1,2,3,4-tetramethylimidazolinium, 1-ethyl-2,3-dimethylimidazolinium, 1-ethyl have high conductivity and further improve the spark voltage. Particularly preferred is -3-methylimidazolinium.

Specific examples of the base component represented by the general formula (6) include 1,2-dimethylpyrazolium, 1-methyl-2-ethylpyrazolium, 1,2-diethylpyrazolium, 1,2- Dipropylpyrazolium, 1,2-dibutylpyrazolium, 1-methyl-2-propylpyrazolium, 1-methyl-2-butylpyrazolium, 1-methyl-2-hexylpyrazolium, 1- Methyl-2-octylpyrazolium, 1-methyl-2-dodecylpyrazolium, 1,2,3,5-tetramethylpyrazolium, 1-ethyl-2,3,5-trimethylpyrazolium, 1 -Ethyl-3-methoxy-2,5-dimethylpyrazolium, 3-phenyl-1,2,5-trimethylpyrazolium, 3-methoxy-5-phenyl-1-ethyl-2-ethylpyrazolium, 1,2-tet And methylene-3,5-dimethylpyrazolium, 1,2-tetramethylene-3-phenyl-5-methylpyrazolium, 1,2-tetramethylene-3-methoxy-5-methylpyrazolium, and the like. .
Among these, 1,2-dimethylpyrazolium, 1-methyl-2-ethylpyrazolium, and 1,2-diethylpyrazolium are particularly preferable because they have high conductivity and further improve the spark voltage. Preferably mentioned.

Specific examples of the base component represented by the general formula (7) include N-methylpyridinium, N-ethylpyridinium, N-propylpyridinium, N-isopropylpyridinium, N-butylpyridinium, N-hexylpyridinium, and N-octyl. Pyridinium, N-dodecylpyridinium, N-methyl-3-methylpyridinium, N-ethyl-3-methylpyridinium, N-propyl-3-methylpyridinium, N-butyl-3-methylpyridinium, N-butyl-4-methyl Examples include pyridinium and N-butyl-4-ethylpyridinium.
Among these, N-methylpyridinium, N-ethylpyridinium, N-butylpyridinium, N-methyl-3-methylpyridinium, N-ethyl-3- from the point which has high electrical conductivity and further improves the spark voltage. Particularly preferred are methylpyridinium and N-butyl-3-methylpyridinium.

  Among the base components represented by the general formulas (1) to (7), the base components represented by the general formulas (1) to (3) are stable over a long period of time, so that high conductivity and spark voltage are obtained. Since it can be obtained, it is particularly preferable.

  In addition, the molar ratio of the carboxylic acid component (A) and the base component (B) in the electrolyte salt may be equimolar, but preferably the excess of the carboxylic acid component (A) increases the spark voltage. It is done. Specifically, carboxylic acid component (A): base component (B) = 1: 1.005 to 1.30 is preferable.

1.0-60 mass% is preferable, as for the addition amount of electrolyte salt, 5.0-50 mass% is more preferable, and 10-40 mass% is mentioned especially preferably.
When the amount is less than 1.0% by mass, there is a defect that sufficient electric characteristics cannot be obtained.

<Organic solvent>
A protic polar solvent or an aprotic polar solvent can be used as the organic solvent used in the electrolytic electrolyte for the electrolytic capacitor, and they may be used alone or in combination of two or more.
Protic polar solvents include monohydric alcohols (methanol, ethanol, propanol, butanol, pentanol, hexanol, cyclobutanol, cyclopentanol, cyclohexanol, benzyl alcohol, etc.), polyhydric alcohols and oxyalcohol compounds ( Ethylene glycol, propylene glycol, glycerin, methyl cellosolve, ethyl cellosolve, methoxypropylene glycol, dimethoxypropanol, etc.).
Examples of aprotic polar solvents include γ-butyrolactone, amides (N-methylformamide, N, N-dimethylformamide, N-ethylformamide, N, N-diethylformamide, N-methylacetamide, N, N-dimethyl). Acetamide, N-ethylacetamide, N, N-diethylacetamide, hexamethylphosphoricamide, etc.), sulfolane (sulfolane, 3-methylsulfolane, 2,4-dimethylsulfolane, etc.), chain sulfone (dimethylsulfone, ethyl) Methylsulfone), cyclic amides (N-methyl-2-pyrrolidone, etc.), carbonates (ethylene carbonate, propylene carbonate, isobutylene carbonate, etc.), nitriles (acetonitrile, etc.), sulfoxides (dimethylsulfoxide, etc.), 2 Imidazolidinones [1,3-dialkyl-2-imidazolidinone (1,3-dimethyl-2-imidazolidinone, 1,3-diethyl-2-imidazolidinone, 1,3-di (n-propyl ) -2-imidazolidinone), 1,3,4-trialkyl-2-imidazolidinone (1,3,4-trimethyl-2-imidazolidinone, etc.)] and the like.
Among these, γ-butyrolactone, ethylene glycol, sulfolane, and dimethyl sulfoxide are preferable.

Preferable organic solvents used in the gel electrolyte for medium and low pressure electrolytic capacitors include γ-butyrolactone alone or γ-butyrolactone as a main component and ethylene glycol or dimethyl sulfoxide as subcomponents.
Further, as a preferable organic solvent used for the gel electrolyte solution for an electrolytic capacitor for high voltage, ethylene glycol alone is preferably mentioned.

The content ratio of γ-butyrolactone and subcomponents in the mixed solvent used in the gel electrolyte for medium and low pressure electrolytic capacitors is preferably a mass ratio of 9.5: 0.5 to 6: 4, and 9: 1 to 7: 3 is more preferable, and 8: 2 is particularly preferable.
By setting the mass ratio, an electrolytic capacitor having higher conductivity can be obtained.

The amount of water contained in the gel electrolyte for electrolytic capacitors is not particularly limited, but is preferably 0.001 to 30% by mass, more preferably 0.005 to 20% by mass, and particularly preferably 0.01 to 10% by mass. It is done.
In the case of less than 0.001% by mass and in the case of more than 30% by mass, there is a drawback that sufficient electric characteristics cannot be obtained.

<Additives>
The gel electrolyte solution for electrolytic capacitors of the present invention may further contain an additive.

Additives include polyvinyl alcohol, dibutyl phosphoric acid or phosphoric acid compound of phosphorous acid, boric acid, mannit, complex compounds such as boric acid and mannit, sorbit and boric acid and polyhydric alcohols such as ethylene glycol and glycerin And nitro compounds such as o-nitrobenzoic acid, m-nitrobenzoic acid, p-nitrobenzoic acid, o-nitrophenol, m-nitrophenol, and p-nitrophenol.
From the viewpoint of improving the spark voltage and conductivity of the gel electrolyte, polyvinyl alcohol, mannitol and nitro compounds are particularly preferred.

  The addition amount is preferably 0.1 to 30% by mass, more preferably 0.5 to 10% by mass. When the amount is less than 0.1% by mass, there is a defect that a sufficient spark voltage cannot be obtained, and when it exceeds 30% by mass, there is a defect that the conductivity is lowered.

As the performance required for an electrolytic capacitor for medium and low pressure, the conductivity is preferably 6 mS / cm or more, more preferably 8 mS / cm or more, and particularly preferably 10 mS / cm or more. The spark voltage is preferably 170 V or higher, more preferably 200 V or higher, and particularly preferably 230 V or higher.
As performance required for the electrolytic capacitor for high voltage, the conductivity is preferably 1 mS / cm or more, more preferably 2 mS / cm or more, and particularly preferably 3 mS / cm or more. The spark voltage is preferably 400 V or higher, more preferably 450 V or higher, and particularly preferably 500 V or higher.

  Hereinafter, the present invention will be described based on examples. In addition, this invention is not limited at all by the Example. In the examples, “part” represents “part by mass”, and “%” represents “% by mass”.

Example 1
While mixing and stirring 166.13 parts (1.0 mol) of phthalic acid and 548 parts of γ-butyrolactone as a solvent, 73.14 parts (1.0 mol) of N, N-dimethylethylamine was added dropwise. After obtaining a dimethylethylamine solution, 39.71 parts of an aqueous solution of 20% colloidal silica (manufactured by Nissan Chemical Industries, Ltd., Snowtex-N, silica particle size 10-20 nm) is mixed and concentrated at 80 ° C. Got. The said electrolyte solution was heated at 120 degreeC for 5 hours, the electrolyte solution was gelatinized, and the gel electrolyte solution for electrolytic capacitors was obtained.

(Examples 2-7, 9)
A gel electrolyte solution for an electrolytic capacitor was obtained in the same manner as in Example 1 except that colloidal silica and a solvent were used so as to correspond to Table 1.

(Example 8)
As a solvent, 1285 parts of ethylene glycol and 396.6 parts of a 20% colloidal silica (Nissan Chemical Industry Co., Ltd., Snowtex-N, silica particle size 10-20 nm) aqueous solution were mixed and concentrated at 80 ° C. An ethylene glycol dispersion of colloidal silica was obtained. To this dispersion, 188.2 parts (1.0 mol) of azelaic acid and 50.38 l (2.0 mol) of ammonia gas were mixed and reacted to obtain an electrolytic solution. The said electrolyte solution was heated at 120 degreeC for 5 hours, and the gel electrolyte solution for electrolytic capacitors was obtained.

(Example 10)
A gel electrolyte solution for an electrolytic capacitor was obtained in the same manner as in Example 8 except that colloidal silica was changed so as to correspond to Table 1.

(Comparative Example 1)
While mixing and stirring 166.13 parts (1.0 mol) of phthalic acid and 548 parts of γ-butyrolactone as a solvent, 73.14 parts (1.0 mol) of N, N-dimethylethylamine was added dropwise. After obtaining a dimethylethylamine solution, 39.71 parts of an aqueous solution of 20% colloidal silica (manufactured by Nissan Chemical Industries, Ltd., Snowtex-N, silica particle size 10-20 nm) is mixed and concentrated at 80 ° C. Got.

(Comparative Example 2)
An electrolytic solution was obtained in the same manner as in Comparative Example 1 except that the colloidal silica corresponding to Table 2 was used.

(Comparative Examples 3-5)
A gel electrolyte solution for an electrolytic capacitor was obtained in the same manner as in Example 1 except that the colloidal silica corresponding to Table 2 was used.

(Comparative Example 6)
A gel electrolyte solution for an electrolytic capacitor was obtained in the same manner as in Example 8 except that the colloidal silica corresponding to Table 2 was used.

(Medium and low pressure electrolytic capacitors)
Using the electrolytic solutions obtained from Examples 1 to 7 and 9 and Comparative Examples 3 to 5, electrolytic capacitors were produced by the following method.
An anode foil formed at 400V was wound together with a separator and a cathode foil, and a capacitor element in which a lead wire was led out from the winding end face was impregnated with the obtained electrolyte at 80 ° C. under reduced pressure. And the opening was closed with a sealing rubber and heated at 120 ° C. for 5 hours to form a gel electrolyte to produce an electrolytic capacitor. This electrolytic capacitor has a rated voltage of 350 WV, a capacitance of 33 μF, and an outer dimension of 12.5φ × 20.

Using the electrolytic solutions obtained from Comparative Examples 1 and 2, electrolytic capacitors were produced by the following method.
An anode foil formed at 400V was wound together with a separator and a cathode foil, and a capacitor element in which a lead wire was led out from the winding end face was impregnated with the obtained electrolyte at 80 ° C. under reduced pressure. And the opening was closed with a sealing rubber to produce an electrolytic capacitor. This electrolytic capacitor has a rated voltage of 350 WV, a capacitance of 33 μF, and an outer dimension of 12.5φ × 20.

(Electrolytic capacitor for high voltage)
Using the gel electrolyte for solid electrolytic capacitors obtained from Examples 8 and 10 and Comparative Example 6, electrolytic capacitors were produced by the following method.
An anode foil formed at 670 V was wound together with a separator and a cathode foil, and a capacitor element in which a lead wire was led out from the winding end surface was impregnated at 80 ° C. under reduced pressure. And the opening was closed with a sealing rubber and heated at 120 ° C. for 5 hours to form a gel electrolyte to produce an electrolytic capacitor. This electrolytic capacitor has a rated voltage of 630 WV, a capacitance of 1000 μF, and an outer dimension of 63.5φ × 130.

The following summarizes the evaluation methods for the conductivity and heat resistance of the electrolyte and the spark voltage and durability of the electrolytic capacitor.
(Conductivity evaluation method)
The electrical conductivity was evaluated using the gel electrolyte (Examples 1 to 10, Comparative Examples 3 to 6) or the electrolyte (Comparative Examples 1 and 2) at 30 ° C. (mS / cm). It measured using SC meter SC72 made from a company. As for durability, the electrical conductivity after 2000 hours was measured under the condition of a temperature of 105 ° C.
(Spark voltage evaluation method)
The spark voltage was evaluated by applying a constant current of 5 mA to the produced electrolytic capacitor at 25 ° C. and examining the voltage-time curve. The voltage at which spark or scintillation was observed including the voltage rise curve was obtained. The spark voltage (V) was used. The durability was determined by measuring the spark voltage after 2000 hours under the condition of a temperature of 105 ° C.

  The electrical conductivity (mS / cm) of the electrolytic solution, the spark voltage (V) of the electrolytic capacitor, and the measurement results of the durability test are shown in Tables 1 and 2.

Abbreviations in the table are as follows.
DMEA-PA: dimethylethylamine-phthalic acid A-AzeA: ammonium-azeleic acid GBL: γ-butyrolactone DMSO: dimethyl sulfoxide EG: ethylene glycol colloidal silica A: acidic colloidal silica (Nissan Chemical Industry Co., Ltd., Snowtex-O) , Solid content 20%, pH 3.8, average particle size 10-20 nm, shape: spherical)
Colloidal silica B: Ammonia-stable colloidal silica (Nissan Chemical Industry Co., Ltd., Snowtech-N, solid content 20%, pH 9.0-10, average particle size 10-20 nm, shape: granular)
Colloidal silica C: sodium stable colloidal silica (Nissan Chemical Industry Co., Ltd., Snowtec-20, solid content 20%, pH 9.5-10, average particle size 10-20 nm, shape: particle size)

  From Tables 1 and 2, it was found that the Examples had higher electrical conductivity and spark voltage and were more durable than the Comparative Examples.

  The electrolytic capacitor using the gel electrolyte solution for electrolytic capacitors of the present invention has high conductivity and spark voltage, and is excellent in durability, and therefore can be used in a wide range of industrial fields.

Claims (5)

Electrolysis containing a polymer of colloidal silica, an electrolyte salt composed of a carboxylic acid component (A) and any one of the basic components (B) represented by the following general formulas (1) to (7), and an organic solvent. In the gel electrolyte for capacitors,
A gel electrolyte for an electrolytic capacitor, characterized in that the polymer of colloidal silica is a polymer obtained by polymerization using acidic colloidal silica or ammonia-stabilized colloidal silica.

(In the formulas (1) to (7), R _{1 to} R ₃₀ are the same or different hydrogen, a C 1-18 alkyl group, a C 1-18 alkoxy group, and a hydroxyl group, and adjacent to each other. Rs may be linked together to form an alkylene group having 2 to 6 carbon atoms.)   The carboxylic acid component (A) is one selected from the group consisting of phthalic acid, maleic acid, salicylic acid, benzoic acid, azelaic acid, sebacic acid, and 1,6-decanedicarboxylic acid. Gel electrolyte for electrolytic capacitors.   3. The gel electrolyte solution for electrolytic capacitors according to claim 1, wherein the average particle size of the acidic colloidal silica or ammonia-stabilized colloidal silica is 1 to 50 nm.   The gel electrolyte for an electrolytic capacitor according to any one of claims 1 to 3, wherein the content of the colloidal silica polymer in the electrolyte for the electrolytic capacitor is 1.0 to 50% by mass.   5. An electrolytic capacitor comprising the gel electrolytic solution for an electrolytic capacitor according to any one of claims 1 to 4.