JPH07105315B2 - Electrolytic solution for driving electrolytic capacitors - Google Patents

Description

TECHNICAL FIELD The present invention relates to an electrolytic capacitor, and more particularly to an electrolytic solution for driving an electrolytic capacitor.

2. Description of the Related Art Conventionally, an ethylene glycol-boric acid-based electrolyte has been used as a medium- and high-pressure driving electrolyte, but this type of electrolyte produces water by an esterification reaction between ethylene glycol and boric acid. Therefore, at 100 ° C or higher, the vapor pressure is high, and it easily reacts with aluminum that is an electrode, and is not suitable for use at high temperatures. In order to improve such drawbacks, as solute, azelaic acid, sebacic acid, 1,10-decanedicarboxylic acid, nonanenic acid (JP-A-61-172323) 1,6-decanedicarboxylic acid or a salt thereof is used. There is an electrolyte to use.

Problems to be Solved by the Invention However, the above-mentioned conventionally used carboxylic acids and salts thereof have insufficient solubility in solvents such as ethylene glycol.

Further, although the conventional carboxylic acid can relatively increase the spark voltage, it is not sufficient, and when these carboxylic acids or salts thereof are used alone as solute, the rated voltage is 350V.

Further, when the electrolytic solution was allowed to stand at a high temperature, the conventional carboxylic acid or its ammonium salt showed a large change at a high temperature such as causing an esterification reaction with ethylene glycol.

The present invention eliminates the above-mentioned conventional drawbacks,
Both spark voltage and specific electric conductivity are high, and it is aimed to improve the change at high temperature and to prolong the service life of middle and high voltage class capacitors.

Means for Solving Problems In order to solve the above problems, the present invention provides a second method.
Having a total of two or more primary and / or tertiary carboxyl groups, a molecular weight of 260 or more, for example 260 to 50,000 or more, usually 300 to 5,000,000, preferably 400 to 5
00,000, more preferably 500 to 200,000 polycarboxylic acid salts are used as solutes.

Examples of the polycarboxylic acid include general formula (1) (HOOCACOO) _m X [CO (OA'CO) _l OH] _n (1) (wherein, X represents a polycarboxylic acid residue, a polyol residue or an oxycarboxylic acid). An acid residue, A is a dicarboxylic acid residue having a secondary and / or tertiary carboxyl group, A'is an oxycarboxylic acid residue having a secondary or tertiary carboxyl group, l Is 0 or an integer of 1 or more,
m and n are 0 or 1 or more such that m + n is 2 or more, usually 0 or 1 to 350 or more, preferably 0.
Or an integer of 1 to 35,000, m = 0 when X is a residue of polycarboxylic acid, and n when X is a residue of polyol.
= 0. ) The polycarboxylic acid represented by

Examples of the polycarboxylic acid of the residue of the polycarboxylic acid represented by X are as follows.

1 Saturated and unsaturated aliphatic polycarboxylic acids such as malonic acid, succinic acid, glutaric acid, adipic acid, sebacic acid, azelaic acid, 1,9-nonanedicarboxylic acid, 1,10-decanedicarboxylic acid, 1,12- Linear saturated dicarboxylic acids such as dodecanedicarboxylic acid, brassylic acid, 1,15-ventadecanedicarboxylic acid, or methylmalonic acid, ethylmalonic acid, butylmalonic acid, methylsuccinic acid, 3-methyladipic acid, 1,6-decane Dicarboxylic acid, dimethylmalonic acid, diethylmalonic acid, 2,2- or 2,3-dimethylsuccinic acid, 2-ethyl-3-methylsuccinic acid, 2,2- or 2,
3- or 2,4- or 3,3-dimethyl glutaric acid, 3-ethyl-3-methyl glutaric acid, 2-butyl octanedioic acid,
A branched saturated dicarboxylic acid such as 5,6-decanedicarboxylic acid,
Or tricarballylic acid, 1,6,11- or 1,10,11- or 5,6,11-pentadecanetricarboxylic acid, 1,2,3,4-butanetetracarboxylic acid, or maleic acid, fumaric acid,
Unsaturated aliphatic dicarboxylic acids such as citraconic acid and alkenylsuccinic acid, or aryl groups, amino groups, carbonyl groups such as phenylmalonic acid, phenylsuccinic acid, 2-aminoadivic acid, 1,3-acetonedicarboxylic acid, etc. Aliphatic polycarboxylic acid having a substituent such as diglycolic acid, polyethyleneoxydiglycolic acid, thioglycolic acid, iminodiacetic acid, nitrilotriacetic acid, ethylenediaminetetraacetic acid, etc. Aliphatic polycarboxylic acid containing elements.

2 saturated and unsaturated cycloaliphatic polycarboxylic acids such as 1,2- or 1,4-cyclohexanedicarboxylic acid, 2
-Or 3-methyl-1,4-cyclohexanedicarboxylic acid, (methyl-) 5-norbornene-2,3-dicarboxylic acid, (methyl-) cyclohexenedicarboxylic acid.

3 aromatic polycarboxylic acids such as 0-phthalic acid, isophthalic acid, trimellitic acid,
Pyromellitic acid, nitrophthalic acid.

4 Heterocyclic polycarboxylic acids, for example 2,6-pyridinedicarboxylic acid.

5 Polymers and copolymers of monomers having a carboxyl group, for example, a molecular weight of 130 or more, for example 130 to 45,000 or more, usually 130 to 4,500,000 polyacrylic acid, a molecular weight of 158 or more, for example 158 to 45,000 or more, usually , 158 to 4,500,000 polymethacrylic acid, polycrotonic acid, a molecular weight of 282 or more, for example 282 to 45,000 or more, usually 282 to 4,500,000 polycinnamic acid, polyvinylbenzoic acid and a monomer for producing the above homopolymer are copolymerized. Molecular weight of 144 or more, for example 144 to 45,0
00 or more, usually 144 to 4,500,000 copolymers.

Of these, the molecular weight is preferably 88 to 450,000.
Is a polycarboxylic acid.

Examples of the polyol having the residue of the polyol represented by X are as follows.

1 saturated and unsaturated aliphatic polyols such as ethylene glycol, 1,3-propanediol,
1,4-Putanediol, 1,5-Pentanediol, 1,6-Hexanediol, 1,12-Dodecanediol, Propylene glycol, 2-Butyl-2-ethyl-1,3-propanediol, 2,3- Or a linear and branched saturated aliphatic diol such as 2,4-putanediol, 1,5-hexanediol, 1,2-decanediol, 1,2-dodecanediol, or 2
-Ethyl-2-hydroxymethyl-1,3-propanediol, 1,2,3-hebutanetriol, 1,1,1-tris (hydroxymethyl) ethane, ventaerythritol, 1,2,7,8
-Saturated aliphatic polyol such as octantetrol, or 5-hexene-1,2-diol, 7-octene-1,2-
Unsaturated aliphatic polyol such as diol, or 2-amino-2-ethyl-1,3-propanediol, 3- (N-
Aliphatic polyols having a substituent such as an amino group, an alkylamino group and an alkoxy group such as benzyl-N-methylamino) -1,2-propanediol and 2-ethoxy-1,2-propanediol.

2 Saturated and unsaturated alicyclic polyols, eg 1,3-cyclopentanediol, (methyl-)
1,2- or 1,3- or 1,4-cyclohexanediol,
Saturated monocyclic alicyclic polyols such as 1,4-cyclohexanedimethanol, 1,2-cycloheptanediol, 1,4- or 1,5-cyclooctanediol, or 1,5-decalindiol, hydrogenated bisphenol A, hydrogenated bisphenol B, 4,8-bis (hydroxymethyl) tricyclo [5,2,1
0] Saturated polycyclic alicyclic polyol such as decane, or 3-
Unsaturated alicyclic polyols such as cyclohexene-1,1-dimethanol and 3,5-cyclohexanediene-1,2-diol.

3 Aromatic polyols, eg resorcin, bisphenol A, bisphenol
B, 2,2-bis (4-hydroxy-3-methylphenyl)
Propane, bis (2- or 4-hydroxyphenyl)
methane.

4 Polyalkylene glycol For example, polyethylene glycol, polypropylene glycol, polybutylene glycol having a molecular weight of 106 to 45,000, or a copolymer thereof.

5 Sugars For example, glucose, galactose, mannose, fructose and other monosaccharides, or maltose, lactose,
Disaccharides such as sucrose, or polysaccharides such as amylose and amylopectin having a molecular weight of 45,000 or less.

6 Heterocyclic polyols 5,6-diamino-2,4-dihydroxypyrimidine, 2,5-furandimethanol, 3-piperidino-1,2-propanediol.

7 Polyols containing different atoms in the main chain For example, 2,2 '-(decamethylenedithio) dimethanol, diethanolamine, triethanolamine, 2,2'
-Bis (hydroxymethyl) -2,2 ', 2'-nitriloethanol, 1,4-bis (2-hydroxyethyl) piperazine, tris (hydroxymethyl) aminomethane, tris (hydroxymethyl) phosphine oxide, bisphenol S .

8 Polymers and copolymers of monomers having a hydroxyl group, for example, a molecular weight of 272 or more, for example 272 to 45,000 or more, usually 272 to 4,500,000 polyhydroxyethyl methacrylate, a molecular weight of 90 or more, for example 90 to 45,000 or more, usually 90 To 4,500,000 polyvinyl alcohol, a molecular weight of 181 or more, for example 181 to 45,000 or more, usually 181 to 4,500,000 vinyl alcohol, hydroxyethyl methacrylate copolymer.

Of these, the molecular weight is preferably 62 to 450,000.
Is a polyol.

Examples of the oxycarboxylic acid of the residue of the oxycarboxylic acid represented by X are as follows.

1 Aliphatic oxycarboxylic acid For example, hydroxyacetic acid, glyceric acid, butyric acid, 3-phenylbutyric acid, 2-hydroxy-2-methylbutyric acid, 2-ethyl-
2-hydroxybutyric acid, 2-hydroxyisobutyric acid, 2-hydroxyvaleric acid, hydroxypivalic acid, 2,2-bis (hydroxymethyl) propionic acid, hydroxyisocaproic acid, 1
0-hydroxydecanoic acid, 12-hydroxydodecanoic acid, 12
-Hydroxystearic acid, mandelic acid, 2- or 3-
Or monocarboxylic acid such as 4-hydroxyphenylacetic acid, 4-amino-3-hydroxybutyric acid, or hydroxymalonic acid, dihydroxymalonic acid, hydroxysuccinic acid, 2
Dihydroxy acids such as hydroxy-2-methylsuccinic acid and tartaric acid, or tricarboxylic acids such as citric acid, 3-hydroxy-3,4-dicarboxypentadecanoic acid and 2-hydroxy-1,2,3-nonadecanetricarboxylic acid.

2 Alicyclic oxycarboxylic acid For example, 1-hydroxy-1-cyclopropanecarboxylic acid, hexahydromandelic acid.

3 Aromatic oxycarboxylic acid For example, salicylic acid, γ-resorcinic acid, 4-hydroxyisophthalic acid.

4 Heterocyclic oxycarboxylic acids, for example 2,6-hydroxyisonicotinic acid.

Of these, oxycarboxylic acids having a molecular weight of 76 to 500 are preferable.

Examples of the dicarboxylic acid at the residue of the dicarboxylic acid having a secondary or tertiary carboxyl group represented by A include the following.

1 Saturated and unsaturated aliphatic dicarboxylic acids such as methylmalonic acid, ethylmalonic acid, phenylmalonic acid, methylsuccinic acid, phenylsuccinic acid, dimethylmalonic acid, diethylmalonic acid, 2,2-dimethylsuccinic acid,
2,3-dimethylsuccinic acid, 2-ethyl-3-methylsuccinic acid, 2,2- or 2,3- or 2,4-dimethylglutaric acid, 1,6-decanedicarboxylic acid, 5,6-decanedicarboxylic acid Saturated aliphatic dicarboxylic acids such as acids or unsaturated aliphatic dicarboxylic acids such as citraconic acid and alkenylsuccinic acid.

2 Saturated and unsaturated alicyclic dicarboxylic acids such as (methyl-) cyclohexanedicarboxylic acid, (methyl-) cyclohexenedicarboxylic acid, (methyl-) norbornanedicarboxylic acid, (methyl-) 5-norbornene-2,3-dicarboxylic acid.

3 aromatic polycarboxylic acid, for example, O-phthalic acid, isophthalic acid, terephthalic acid,
Nitrophthalic acid.

Among these, dicarboxylic acids having a molecular weight of 118 to 500 are preferable.

Examples of the oxycarboxylic acid as the residue of the oxycarboxylic acid having a secondary or tertiary carboxyl group represented by A ′ are as follows.

1 Aliphatic oxycarboxylic acid, for example, 2-hydroxyisobutyric acid, 2-hydroxy-2-
Methyl butyric acid, 2-ethyl-2-hydroxybutyric acid, hydroxypivalic acid.

2 Alicyclic oxycarboxylic acid For example, 1-hydroxy-1-cyclopropanecarboxylic acid, hexahydromandelic acid.

3 Aromatic oxycarboxylic acid, for example salicylic acid.

Of these, oxycarboxylic acids having a molecular weight of 104 to 500 are preferable.

Further, as the polycarboxylic acid, a compound represented by the general formula (2) (In the formula, X, Y and Z may be the same or different and each is hydrogen, a lower alkyl group, an aryl group or a carboxyl group-containing group, and at least one of X, Y and Z is a carboxyl group-containing group. A polymer or copolymer having a unit represented by

Examples of X, Y and Z are lower alkyl groups such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl and t-butyl, cycloalkyl groups such as cyclopropyl, cyclopentyl and cyclohexyl, aryl groups such as phenyl and naphthalyl, Examples thereof include carboxyl group-containing groups such as carboxyl group, carboxymethyl group and carboxyphenyl group.

Examples of the monomer forming the unit represented by the general formula (2) include acrylic acid, methacrylic acid, crotonic acid, cinnamic acid, vinylcarboxylic acid and other monocarboxylic acids, maleic acid, fumaric acid, itaconic acid, citracone. Examples thereof include acids, polycarboxylic acids such as mesaconic acid, methylenemalonic acid, and aconitic acid, or a mixture of two or more thereof.

Further, these polycarboxylic acid monomers may be substituted with C _{1 to} C ₁₈ aliphatic or alicyclic alcohols, alkylenes (C _{2 to} C ₄ ).
Glycols, polyalkylene (C ₂ -C ₄₎ that partially esterified with glycol (methyl maleate, mono-hydroxyethyl maleate and the like) and ammonia, partially those amidated with a primary or secondary amine (maleic Acid monoamide, N-methyl maleic acid monoamide, N, N-diethyl maleic acid monoamide, etc.) are also used.
Of these, acrylic acid, methacrylic acid, maleic acid and crotonic acid are preferred.

In addition, acrylic acid, methacrylic acid, maleic acid,
A mixture in which other acids are mixed in such a range that the molar content of acids other than crotonic acid does not exceed 50% is also preferable.

Also, a copolymer with a monomer having no carboxyl group can be used.

Examples of the monomer having no carboxyl group capable of copolymerizing with the monomer having a carboxyl group include (meth) acrylic acid esters [C _{1 to} C ₁₈ aliphatic (methyl, ethyl, propyl, butyl, 2-ethylhexyl, esters of stearyl, etc.) and alcohol (meth) acrylic acid or alkylene (C ₂ -C ₄₎ glycol (ethylene glycol, propylene glycol, 1,4-butanediol, etc.) and polyalkylene (C ₂ -C ₄₎ glycol (Ethylene of (polyethylene glycol, polypropylene glycol, etc.) with (meth) acrylic acid]; (meth) acrylamide or N-substituted (meth) acrylamide [(meth) acrylamide, N-methyl (meth) acrylamide, N-methylol (meth ) Acrylamide etc.]; vinyl ester Is an acrylic ester [vinyl acetate, allyl acetate, etc.]; vinyl ether or allyl ether [butyl vinyl ether, dodecyl allyl ether, etc.]; unsaturated nitrile compound [(meth) acrylonitrile, crotonnitrile, etc.]; unsaturated alcohol [(meth) allyl alcohol , Vinyl alcohol, etc .; unsaturated amines [(meth) allylamine, etc.]; heterocycle-containing monomers [vinylpyrrolidone, vinylpyridine, etc.]; olefinic aliphatic hydrocarbons [ethylene, propylene, butylene, isobutylene, pentene, (C ₆ ~ C
₅₀ ) α-olefins, etc.]; olefinic alicyclic hydrocarbons [cyclopentene, cyclohexene, cycloheptene, norbornene, etc.]; olefinic aromatic hydrocarbons [styrene, α-methylstyrene, stilbene, etc.];
Unsaturated imide (maleimide etc.).

And so on. Of these, esters of C _{1 to} C ₁₈ aliphatic (methyl, ethyl, propyl, butyl, 2-ethylhexyl, stearyl, etc.) alcohols with (meth) acrylic acid and polyalkylene (C _{2 to} C ₄ ) glycols are preferred. Ester of (meth) acrylic acid with (polyethylene glycol, polypropylene glycol, etc.); olefinic aliphatic hydrocarbons [ethylene, isobutylene,
Diisobutylene, (C ₆ -C ₅₀ ) α-olefin, etc.];
Olefinic aromatic hydrocarbons [styrene, α-methylstyrene, etc.]; unsaturated imides [maleimide, etc.]; vinylpyrrolidone and (meth) acrylonitrile, crotonnitrile.

The amount of monomer to be copolymerized is usually 20 to 95%, preferably 40 to 90%, based on the weight of the copolymer. The molecular weight of these polymers or copolymers is 260 or more, usually 260 to 50,0.
00 or more, usually 300 to 5,000,000, preferably 5
It is from 00 to 500,000, more preferably from 700 to 200,000.

The polymer or copolymer having the unit represented by the general formula (2) may be a polymer or a copolymer of the above-mentioned monomers, but the above-mentioned monomers such as ester, nitrile, amide and imide and The ester group, cyano group, amide group, imide group, acid anhydride, etc. of a polymer or copolymer obtained by polymerizing or copolymerizing one or more types of unsaturated carboxylic acid anhydride monomers (maleic anhydride, etc.) It may be a polymer or copolymer having a carboxyl group obtained by hydrolysis, half-esterification and half-amidation, and the carboxyl group of the polymer or copolymer of monomers having the above-mentioned carboxyl group may be partially substituted. It may be esterified or amidated.

The molecular weight of these polymers or copolymers is 260 or higher, for example 260 to 50,000 or higher, usually 300 to 5,000,00.
0, preferably 500 to 500,000, more preferably 700
It is 200,000.

Operation Usually, deterioration at high temperature occurs due to reaction of carboxyl group of carboxylic acid such as esterification reaction with solvent. Focusing on this point, the present invention uses a carboxylic acid having a secondary and / or tertiary carboxyl group. It is considered that secondary and / or tertiary carboxyl groups are less likely to undergo an esterification reaction or the like due to steric hindrance and that a stable electrolytic solution can be obtained at high temperatures.

Examples Hereinafter, examples according to the present invention will be described.

Table 1 shows the examples of the present invention and the conventional electrolytic solutions, as well as the specific conductivity and spark voltage at room temperature.

As is clear from Table 1, in the present invention, the spark voltage can be increased without lowering the specific conductivity as compared with the conventional example.

The figure shows the changes over time in the specific conductivity of the electrolytic solutions at 105 ° C. in Examples 1, 2, 3, 4, 7, 9 and Conventional Examples 1 and 2. It can be seen that the present invention has a small change at high temperature as compared with the conventional example, and can have a long life at high temperature.

EFFECTS OF THE INVENTION As described above, according to the present invention, the spark voltage is high, the change in high temperature is small compared to the conventional electrolytic solution, and it is possible to extend the life of the medium-high voltage class electrolytic capacitor. , Of great industrial value.

[Brief description of drawings]

The figure is a characteristic diagram showing changes over time in specific electric conductivity of an electrolytic solution according to an example of the present invention at 105 ° C. in comparison with a conventional electrolytic solution.

Front page continued (72) Inventor Washio Yukari 1006 Kadoma, Kadoma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (72) Keiji Mori, 1006 Kadoma, Kadoma City, Osaka Matsushita Electric Industrial Co., Ltd. (72) Inventor ▲ Yoshi ▼ Shingo Ta 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (72) Inventor Yoshiteru Kuwae 5-6 Nishiwazu Waki, Yawata City, Kyoto Prefecture (72) Kazushio Shiono, Kyoto City East, Kyoto Prefecture 7-3 Tsuji-machi, Goyo, Sengakuji, Yama-ku (72) Inventor Takaaki Ki, 22-13 Kitanosho, Gogasho, Uji City, Kyoto Prefecture

Claims (3)

[Claims] 1. An electrolytic solution for driving an electrolytic capacitor, which comprises a salt of a polycarboxylic acid having a total of two or more secondary and / or tertiary carboxyl groups and a molecular weight of 260 or more. 2. A polycarboxylic acid is represented by the general formula (1) (HOOCACOO) _m X [CO (OA'CO) _l OH] _n (1) (wherein, X is a residue of polycarboxylic acid, the residue of the polyol. Group or a residue of an oxycarboxylic acid, A is a residue of a dicarboxylic acid having a secondary and / or tertiary carboxyl group, and A'is a residue of an oxycarboxylic acid having a secondary or tertiary carboxyl group. Residue, l is 0 or an integer of 1 or more,
m and n are each represented by 0 or an integer of 1 or more such that m + n is 2 or more).
An electrolytic solution for driving an electrolytic capacitor according to the item. 3. The polycarboxylic acid has the general formula (2): (In the formula, X, Y and Z may be the same or different and each is hydrogen, a lower alkyl group, an aryl group or a carboxyl group-containing group, and at least one of X, Y and Z is a carboxyl group-containing group. The electrolytic solution for driving an electrolytic capacitor according to claim 1, which is a polymer or a copolymer having a unit represented by the following formula.