JP2005310951A - Electrolytic solution for electrolytic capacitors and capacitor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrolytic solution and a capacitor, superior in both the conductivity of electrolytic solution and the withstand voltage. <P>SOLUTION: The electrolytic solution for capacitors possesses an oxyalkylene group in the side chain of a polymer principal chain containing nitrogen atoms, such as reactants of polyamide, polyimide, poly imidazole, poly alkylene polyamine, polyurethane, an epoxy compound, and amine. The electrolytic solution for capacitors for which the rate of an oxyalkylene group consists of the compound (A) and electrolyte (B) which are 30 to 99 weight%, and the capacitors use it. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an electrolytic solution for electrolytic capacitors, and more particularly to an electrolytic solution for electrolytic capacitors having a high withstand voltage, and an electrolytic capacitor using the electrolytic solution.

  Conventionally, as an electrolytic solution for medium- and high-voltage electrolytic capacitors, an electrolyte is dissolved in a solvent mainly composed of ethylene glycol, and a synthetic polymer such as polyethylene glycol or polyglycerin is added for the purpose of improving withstand voltage. .

However, although polyethylene glycol (for example, Patent Document 1) and polyglycerin (for example, Patent Document 2) have a large effect of improving the withstand voltage, there is a problem that the electrical conductivity of the electrolytic solution is lowered. For this reason, the electrolyte solution excellent in both the electrical conductivity and withstand voltage of electrolyte solution was calculated | required.
Japanese Examined Patent Publication No. 3-76776 JP-A-2-194611

The present invention has reached the present invention as a result of intensive studies to solve the above-mentioned problems.
That is, the present invention relates to an electrolytic solution for a capacitor, characterized by comprising a compound (A) having an oxyalkylene group in the side chain of a polymer main chain containing a nitrogen atom and an electrolyte (B), and an electrolytic capacitor using the same. is there.

  The electrolytic solution for electrolytic capacitors of the present invention and a capacitor using the same exhibit excellent electrical conductivity and withstand voltage characteristics.

  In the present invention, the polymer main chain containing a nitrogen atom in the compound (A) having an oxyalkylene group in the side chain of the polymer main chain containing a nitrogen atom includes polyamide (a), polyimide (b), polyimidazole ( c), a polyalkylene polyamine (d), a polyurethane (e), a reaction product (f) of an epoxy compound and an amine, and a copolymer of two or more thereof. The number average molecular weight of these polymer main chains is preferably 103 to 30,000, more preferably 103 to 10,000.

Specific examples of the polyamide (a) include compounds synthesized by reaction with the following divalent or higher carboxylic acid compounds and divalent or higher amine compounds. The divalent or higher carboxylic acid compound is preferably a carboxylic acid having 2 to 30 carbon atoms, for example, saturated oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, etc. Aliphatic carboxylic acids; unsaturated aliphatic carboxylic acids such as maleic acid, fumaric acid, citraconic acid, mesaconic acid and dimer acid; alicyclic carboxylic acids such as camphoric acid; aromatics such as phthalic acid, isophthalic acid and terephthalic acid Examples thereof include carboxylic acids and mixtures of two or more thereof. Of these, unsaturated aliphatic carboxylic acids are preferred. If necessary, trivalent or higher carboxylic acids such as trimellitic acid, trimesic acid, hydromellitic acid and the like may be used in combination.
The amine compound having 2 or more valences is preferably an amine having 2 to 30 carbon atoms, such as ethylenediamine or polyalkylene (polyamine diethylenetriamine, triethylenetetraamine, tetraethylenepentamine, pentaethylenehexamine, tetramethylenediamine, hexamethylenediamine, Aliphatic polyamines such as diethylenetriamine, etc .; Aliphatic polyamines such as 4,4′-diaminodicyclohexylmethane, 1,4-diaminocyclohexane and isophoronediamine, and fats having aromatic rings such as xylylenediamine and tetramethylxylylenediamine Group polyamines, and mixtures of two or more thereof. Of these, aliphatic polyamines are preferred. The polyamide (a) is obtained by an amidation reaction by dehydration reaction between the carboxylic acid and an amine. The reaction temperature is preferably 100 to 150 ° C., and the reaction time is 1 to 24 hours. The end point is determined by the acid value.

  Specific examples of the polyimide (b) in the present invention include compounds synthesized by a reaction with a tetracarboxylic anhydride such as pyromellitic acid and an amine compound that is divalent (the number of amino groups having hydrogen) or more. The divalent or higher valent amine compound is preferably an amine having 2 to 30 carbon atoms, and examples thereof include the same compounds as those described above in (a). The preferred ones are the same. The temperature of the imidization reaction by the dehydration reaction between the carboxylic acid and the amine is preferably 100 to 150 ° C., and the reaction time is preferably 1 to 24 hours. The end point of the reaction can be determined by the acid value.

  Specific examples of the polyimidazole (c) include tetravalent amine compounds such as 5,5′-methylene-1,2,1 ′, 2′-tetraaminodiphenyl, and o-dibenzoic acid phenyl ester. And compounds synthesized by reaction with a divalent carboxylic acid ester compound.

  Specific examples of the polyalkylene polyamine (d) in the present invention include those having 2 to 50 carbon atoms and 2 to 26 carbon atoms, preferably those having 2 to 30 carbon atoms and 2 to 16 carbon atoms such as the above ( The same ones as mentioned in a) can be used. Preferred is pentaethylenehexamine.

The polyurethane (e) in the present invention is a compound synthesized by a reaction with an isocyanate compound (e-1) and a compound (e-2) containing active hydrogen, and (e-1) is an isocyanate group. The following compounds having 2 or more are mentioned.
1,3- and / or 1,4-phenylene diisocyanate, 2,4-, 2,6-tolylene diisocyanate (TDI), crude TDI, 2,4′-, 4,4′-diphenylmethane diisocyanate (MDI), Aromatic polyisocyanates having 6-20 carbon atoms (excluding the carbon number in the NCO group) such as crude MDI, 1,5-naphthylene diisocyanate;

C2-C18 aliphatic polyisocyanates such as ethylene diisocyanate, hexamethylene diisocyanate (HDI), tetramethylene diisocyanate, lysine diisocyanate; isophorone diisocyanate (IPDI), dicyclohexyl diisocyanate, dicyclohexylmethane diisocyanate (H-MDI), cyclohexylene diisocyanate C 4-15 alicyclic polyisocyanate such as hydrogenated tolylene diisocyanate (HTDI); m- and / or p-xylylene diisocyanate (XDI), α, α, α ′, α′-tetramethylxylyl C8-15 aromatic aliphatic polyisocyanate such as range isocyanate (TMXDI);
Modified products of the above polyisocyanates such as urethane groups, carbodiimide groups, allophanate groups, urea groups, burette groups, uretdione groups, uretonimine groups, isocyanurate groups, oxazolidone group-containing modified products; among these, preferred are TDI, MDI XDI and TMXDI, particularly preferably HDI and MDI.

  (E-2) preferably includes a compound having 1 to 10 active hydrogens, and specifically includes a hydroxyl group-containing compound (ee-1), an amino group-containing compound (ee-2), and a thiol group-containing compound. (Ee-3) etc. are mentioned. Examples of (ee-1) include divalent to octavalent polyhydric alcohols, polyhydric phenols, and the like. Specifically, 1,3-butylene glycol, 1,4-butanediol, 1,6-hexanediol, 3 -Methylpentanediol, diethylene glycol, neopentyl glycol, 1,4-bis (hydroxymethyl) cyclohexane, 1,4-bis (hydroxyethyl) benzene, 2,2-bis (4,4'-hydroxycyclohexyl) propane, etc. Dihydric alcohols; Trihydric alcohols such as trimethylolpropane; 4- to 8-valent alcohols such as pentaerythritol, sorbitol, xylit, mannitol, dipentaerythritol, glucose, fructose, and sucrose; Phenol; bisphenol A, bis Examples include bisphenols such as phenol F and bisphenol S; polybutadiene polyols; castor oil-based polyols; (co) polymers of hydroxyalkyl (meth) acrylates, polyfunctional polyols such as polyvinyl alcohols, and the like, and mixtures of two or more thereof. .

  Examples of the amino group-containing compound (ee-2) include monoamines such as aniline; polyalkylene polyamines exemplified in (a) such as hexamethylenediamine and diethylenetriamine; and heterocyclic polyamines such as piperazine and N-aminoethylpiperazine. Alicyclic polyamines such as dicyclohexylmethanediamine and isophoronediamine; aromatic polyamines such as phenylenediamine, tolylenediamine, diphenylmethanediamine and polyphenylmethanepolyamine; number average molecular weight obtained by condensation of dicarboxylic acid with excess polyamines Polyamide polyamines of 100 to 5,000; polyether polyamines having a number average molecular weight of 100 to 5,000; hydrazines (monoalkyl hydrazine, etc.), dihydrazides (isophthalic acid dihydrazide, Le acid dihydrazide, etc.), guanidines (butyl guanidine, 1-cyanoguanidine, etc.); dicyandiamide; and mixtures of two or more thereof.

Examples of the thiol group-containing compound (ee-3) include monovalent or divalent to polyvalent thiols. Specific examples include octyl thiol, octane dithiol, decanedithiol thiol, and the like, and mixtures of two or more thereof. The alkyl group portion of these thiol group-containing compounds may be linear or branched.
When reacting with an isocyanate group, if necessary, a low molecular weight polyol (urethane curing agent; for example, 1,4-butanediol, ethylene glycol, propylene glycol, diethylene glycol) having a molecular weight of 62 to 400, a urethanization accelerating catalyst or the like is mixed. It is preferable to react.
Examples of urethanization-promoting catalysts include tin-based catalysts such as trimethyltin laurate, dimethyltin dilaurate and dibutyltin maleate; lead-based catalysts such as lead oleate, lead naphthenate and lead octenoate; naphthenic acids such as cobalt naphthenate Examples thereof include metal salts, phenylmercury propionate and the like; amine-based catalysts such as triethylenediamine and dimethylethanolamine and organic acid salts thereof (formate and the like) and the like, and combinations of two or more of these. The blending ratio of the urethanization promoting catalyst is preferably 0 to 10% by weight or less, more preferably 0.01 to 5% by weight.
The reaction method is not particularly limited, but the equivalent ratio of the active hydrogen-containing compound (e-2) and the isocyanate group is preferably 1: 0.1 to 1: 1, more preferably 1: 0.3 to 1: 1. (E-2) is mixed with isocyanate or a derivative thereof, and is preferably obtained by heating at a temperature of 10 to 250 ° C., more preferably 15 to 200 ° C., and particularly preferably 20 to 160 ° C. for addition reaction. The end point of the reaction can be judged by the isocyanate content and the hydroxyl value. The reaction time is preferably 1 to 24 hours.

Specific examples of the reaction product (f) of the epoxy compound and amine compound in the present invention include compounds synthesized by reaction with the following epoxy compound (f-1) and amine compound (f-2). Examples of the epoxy compound (f-1) include aliphatic glycidyl etherified products and aromatic glycidyl etherified products. Specifically, monovalent aliphatic glycidyl ethers such as methyl glycidyl ether, butyl glycidyl ether and allyl glycidyl ether, and aliphatic glycidyl ethers such as propylene diglycidyl ether; phenyl glycidyl ether and diglycidyl etherified products of bisphenol A, etc. Aromatic glycidyl etherified products and mixtures of two or more of these may be mentioned. Examples of the amine compound (f-2) include the same compounds as those described in (ee-2) above.
The reaction method is not particularly limited, but the equivalent ratio of amino group to epoxy group is preferably 1: 0.1 to 1: 1, more preferably 1: 0.3 to 1: 1, and (f-1) and (f- It is obtained by mixing 2) and heating at a temperature of preferably 50 to 250 ° C., more preferably 70 to 200 ° C., and particularly preferably 120 to 160 ° C. for addition reaction. The end point of the reaction can be judged by epoxy equivalent and NMR. The reaction time is preferably 1 to 24 hours.

  Among these, an alkylene polyamine (d) is preferable, and a polyamide (a) is particularly preferable.

In the present invention, the oxyalkylene group in the side chain is a hydroxyalkyl group or polyoxyalkylene group having 2 to 8 carbon atoms, preferably 2 to 4 carbon atoms, specifically 2-hydroxyethyl group or 2-methyl group. 2-hydroxyethyl group, 1-methyl-2-hydroxyethyl group, 4-hydroxybutylene group and other hydroxyalkyl groups; polyoxyethylene group, polyoxypropylene group, polyoxybutylene group, polyoxystyrene group, 2 types Examples thereof include polyoxyalkylene groups such as oxyalkylene groups in the above-mentioned alkylene mixture, and mixtures of two or more thereof. Here, poly in the polyoxyalkylene group means 2 or more, oxygen in the hydroxyalkyl group is 1, and ether oxygen is 1 or more. The number average molecular weight of the hydroxyalkyl group or polyoxyalkylene group is preferably 45 to 128,700, more preferably 45 to 89,100. When the number average molecular weight is 128,700 or less, the viscosity of the compound (A) does not increase and the handling is easy, and when it is 45 or more, excellent withstand voltage characteristics can be exhibited when the electrolyte is used. .
The proportion of the oxyalkylene group in (A) is preferably 30 to 99% by weight, more preferably 40 to 90%. When the proportion is 30 to 99%, excellent withstand voltage characteristics can be exhibited when the electrolyte is used.

The compound (A) having an oxyalkylene group in the side chain of the polymer main chain containing a nitrogen atom is one in which the oxyalkylene group is bonded to the polymer main chain of the above (a) to (f). ) Addition of an alkylene oxide having 2 to 8 carbon atoms, preferably 2 to 4 carbon atoms, to the active hydrogen of (a) to (f), or (ii) introduction of the oxyalkylene group into the side chain by a graft reaction (Iii) (A) can be obtained by reacting the above raw materials (a) to (f) to which an oxyalkylene group has been added. The method (i) is preferred. Additional conditions will be described later.
The number average molecular weight of the compound (A) having an oxyalkylene group in the side chain of the polymer main chain containing a nitrogen atom is preferably 147 to 130,000, more preferably 147 to 90,000. When the number average molecular weight is 130,000 or less, the viscosity of the compound (A) does not increase and handling is not difficult. When it is 147 or more, excellent withstand voltage characteristics can be exhibited when the electrolyte is used.

Among (A), a compound having an oxyalkylene group in the side chain of the polyamide main chain is preferable. More preferably, (A) contains a compound represented by the following formula (I) as a main component.
formula

In the above formula (I), R ¹ is an alkylene group or an alkenylene group. Although it does not limit about carbon number, Preferably it is a C1-C50 alkylene group or an alkenylene group.
In the above formula (I), R ² and R ³ are hydrogen or an oxyalkylene group, and both may be the same or different. The proportion of oxyalkylene groups in the molecule is preferably 30 to 99% by weight, more preferably 40 to 90%. When the proportion is 30 to 99%, excellent withstand voltage characteristics can be exhibited when the electrolyte is used. The number of oxyalkylene groups contained in the molecule is preferably 4 to 1,100, more preferably 4 to 900.
Specific examples of the oxyalkylene group are the same as the specific examples and molecular weights described in the above-mentioned side chain hydroxyalkyl group or polyoxyalkylene group. A preferable one is a 2-hydroxyethyl group or a polyoxyethylene group. More preferably, it is a group represented by the following formula (II).

formula
_{- {(C 2 H 4 O} ) p (AO) q} -H (II)

In the above formula (II), the (C ₂ H ₄ O) portion is formed by addition of ethylene oxide. A represents an alkylene group having 3 or more carbon atoms, preferably 3 to 8 carbon atoms, more preferably 3 carbon atoms, and the part (AO) is formed by addition of an alkylene oxide having 3 or more carbon atoms. Examples of such alkylene oxide include propylene oxide, 1,2- or 2,3-butylene oxide, tetrahydrofuran, styrene oxide, and the like.

In the above formula (II), p is preferably an integer of 1 or more with an average of 1 to 40, more preferably 1 to 20, and particularly preferably an integer of 1 or more of 1 to 10. q is preferably an integer of 0 or 1 or more, with an average of 0 to 40, and more preferably 0 to 20. (P + q) is preferably an integer having an average of 1 to 80, more preferably 1 to 40. When (p + q) is 80 or less, the viscosity of (A) does not increase and handling is not difficult. The ratio of p and q is preferably 1: 0 to 1:40, more preferably 1: 0 to 1:20. In the above formula (II), {(C ₂ H ₄ O) _p (AO) _q } represents block addition or random addition when q ≠ 0. In the case of block addition, the order of addition is not limited.

In said formula (I), n is an integer of 2-20, a preferable thing is 2-10, and a particularly preferable thing is 2-5. m is an integer of 1-20, a preferable one is 1-15, and a particularly preferable one is 1-10. k is an integer of 1 to 50, preferably 1 to 40, and particularly preferably 1 to 30.

The compound represented by the above formula (1) can be obtained by adding alkylene oxide to a polyamide obtained by reacting the divalent carboxylic acid of the above (a) with a polyalkylene polyamine. The reaction temperature and time of the amidation reaction may be the same as those described in (a). The compounding ratio of the polyalkylene polyamine and the divalent carboxylic acid is 1: 0.26 to 1: 0.98 in terms of equivalent ratio of primary amino group to carboxylic acid, preferably 1: 0.30 to 1: 0. 90. The end point of the reaction can be measured by acid value, amine value, number average molecular weight, residual monomer check by gas chromatography or the like.
Alkylene oxide is added so that the proportion of the oxyalkylene group in (A) is preferably 30 to 99% by weight. Examples of the method for adding alkylene oxide include, but are not limited to, single addition, random addition when two or more types of alkylene oxide are used, and block addition. Single addition is preferred.
A catalyst is preferably used for the addition reaction. Examples of the catalyst include an alkali catalyst such as a hydroxide [a hydroxide of an alkali metal or alkaline earth metal such as KOH, NaOH, CsOH, Ca (OH) ₂ ], an oxide (K ₂ O ₂ , CaO, BaO). Alkali metal or alkaline earth metal oxides), alkali metals (Na, K, etc.) and hydrides thereof (NaH, KH, etc.) and amines (triethylamine, trimethylamine, etc.). The amount of the catalyst used is preferably 0.1 to 0.5% by mass with respect to the compound represented by the above formula (1). The temperature of the addition reaction is preferably 80 to 160 ° C., the pressure is preferably 0 to 0.5 MPa, and the reaction time is preferably 1 to 48 hours.
The number average molecular weight of the compound represented by the formula (1) is preferably 538 to 100,000, more preferably 538 to 90,000. When the number average molecular weight is 100,000 or less, the viscosity of the compound (A) does not increase and handling is not difficult. When it is 538 or more, excellent withstand voltage characteristics can be exhibited when the electrolyte is used.

In the electrolytic solution for electrolytic capacitors of the present invention, the compound (A) acts as a solvent for the electrolyte (B). As the solvent of the electrolytic solution, other known solvents may be used in combination with (A). Examples of other solvents include ethylene glycol, water, lactone solvents (γ-butyrolactone, γ-valerolactone, δ-valerolactone, 3-methyl-1,3-oxazolidine-2-one and 3-ethyl-1, 3-oxazolidin-2-one), amide solvents (N-methylformamide, N, N-dimethylformamide, N-methylacetamide, N-methylpyrrolidinone, etc.), alcohol solvents (methylcellosolve, propylene glycol, 1,4-butanediol, glycerin, polyoxyalkylene polyol, cyclohexanediol, etc.), ether solvents (methylal, 1,2-dimethoxyethane, 1-ethoxy-2-methoxyethane, 1-2-diethoxyethane, etc.) , Nitrile solvents (acetonitrile, 3-methoxypropionitrile, etc. , Furan solvents (2,5-dimethoxytetrahydrofuran, etc.), 2-imidazolidinones (1,3-dimethyl-2-imidazolidinone, etc.) and pyrrolidones, and two or more of these are used in combination. May be. Of these, ethylene glycol is preferred.
The weight ratio of (A) in the mixed solvent of (A) and another solvent is preferably 0.1% to 50%, more preferably 0.1% to 20%.

  As electrolyte salt (B), a well-known electrolyte is mentioned, Preferably ammonium salt is mentioned. This can be used in combination with an amine salt, a quaternary ammonium salt and a diazabicycloalkene salt. This group is hereinafter referred to as a combination salt. The amine salt is a salt of an amine and an acid, and the amine is preferably one having 1 to 4 N atoms and 1 to 40 carbon atoms, for example, primary amine (methylamine, ethylamine, propylamine, butylamine, ethylenediamine, etc.) Secondary amines (dimethylamine, diethylamine, dipropylamine, methylethylamine, diphenylamine etc.) and tertiary amines (trimethylamine, triethylamine, tripropylamine, triphenylamine etc.) can be mentioned. Trimethylamine is preferable. Examples of acids that form salts include boric acid, phosphoric acid, carboxylic acids having 1 to 50 carbon atoms and 1 to 3 functional groups (formic acid, acetic acid, propionic acid, maleic acid, citraconic acid, phthalic acid, adipic acid, azelaic acid, Benzoic acid, butyloctanoic acid, formic acid, decanedicarboxylic acid, etc.).

  The quaternary ammonium group in the quaternary ammonium salt is preferably a tetraalkylammonium having 4 to 50 carbon atoms (tetramethylammonium, tetraethylammonium, tetrapropylammonium, tetrabutylammonium, methyltriethylammonium, dimethyldiethylammonium, etc.), And pyridinium (1-methylpyridinium, 1-ethylpyridinium, 1,3-diethylpyridinium, etc.). The diazabicycloalkene salt is a salt of a diazabicycloalkene and an acid. As the diazabicycloalkene, 1,5-diazabicyclo (4,3,0) nonene-5, 1,8-diazabicyclo (5,4, 0) Undecene-7 and the like. The counter ion is an anion obtained by removing a proton from the above acid, and preferably decanedicarboxylic acid. Of those exemplified as these electrolyte salts, ammonium salts of carboxylic acid or boric acid are preferable. The mixing weight ratio of the ammonium group and the counter anion is preferably ammonium group / counter anion = 100/0 to 30/70, more preferably 100/0 to 50/50. Within this range, preferable capacitor performance can be obtained.

  In the electrolytic solution of the present invention, the water content of the electrolytic solution is preferably 1% by weight or less, more preferably 0.1% by weight or less, because the generation of gas due to hydrolysis remarkably causes problems such as swelling of the capacitor. Considering the repair ability of the anodized film, it is preferably 0.0001% by weight or more, more preferably 0.01% by weight or more.

  The electrolytic solution in the present invention is used for an electrolytic capacitor. The electrolytic capacitor is not particularly limited. For example, an aluminum oxide foil and a cathode aluminum foil are wound on the surface with a separator interposed therebetween, and impregnated with the electrolytic solution of the present invention, and stored in a bottomed cylindrical aluminum case. After that, a wound aluminum electrolytic capacitor configured by sealing the opening of the aluminum case with a sealing agent is preferable.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further, this invention is not limited to this. Below, a part and% show a mass part and the mass%, respectively.

Example 1
696 parts of pentaethylenehexamine (trade name: manufactured by PEHA Tosoh Corporation) and 1152 parts of “Tsunodyme205S” (dimer acid: manufactured by Tsukino Food Industry Co., Ltd.) are mixed into a stainless steel autoclave with stirring and temperature control functions. After the inside was replaced with nitrogen, the reaction was carried out at 120 ° C. until the acid value became 4.0 or less.
Next, 2.0 parts of potassium hydroxide was added, and at 120 ° C., 1420 parts of ethylene oxide and 355 parts of propylene oxide were introduced so that the gauge pressure would be 1 to 3 kgf / cm ² . After reacting at 120 ° C. for 8 hours, 40 parts of “KYOWARD 600” (manufactured by Kyowa Chemical Industry Co., Ltd .; adsorbent) was added to the reaction product, and the catalyst was adsorbed at 80 ° C., followed by filtration. A polyamide (A-1) having a group and an oxypropylene group having a random oxyalkylene group was obtained. The number average molecular weight Mn of (A-1) was 3,600. Of these, the weight of the oxyalkylene group portion was 49%.
Next, 5 parts of (A-1), 80 parts of ethylene glycol, and 20 parts of 1,6-decanedicarboxylic acid ammonium salt were mixed at room temperature to prepare an electrolytic solution.

Example 2
A polyamide was synthesized in the same manner as in Example 1.
Next, 2.0 parts of potassium hydroxide was added, and at 600C, 5600 parts of ethylene oxide and 1400 parts of propylene oxide were introduced so that the gauge pressure was 1 to 3 kgf / cm <2>. After reacting at 120 ° C. for 8 hours, 40 parts of “KYOWARD 600” is added to the reaction product, the catalyst is adsorbed at 80 ° C., and oxyethylene and oxypropylene groups are random in the side chain by filtration. A polyamide (A-2) having a group was obtained. The number average molecular weight Mn of (A-2) was 8,850. Of these, the weight of the oxyalkylene group portion was 79%.
Thereafter, 5 parts of (A-2), 80 parts of ethylene glycol, and 20 parts of 1,6-decanedicarboxylic acid ammonium salt were mixed at room temperature to prepare an electrolytic solution.

Example 3
721 parts of diethylenetriamine (trade name: manufactured by DETA Tosoh Corp.) and 3468 parts of “Tsunodyme 205S” were charged into a stainless steel autoclave having a stirring and temperature control function, and after the inside of the mixed system was replaced with nitrogen, the acid value was 4. The reaction was carried out at 120 ° C. until it became 0 or less.
Next, 2.0 parts of potassium hydroxide was added, and 3500 parts of ethylene oxide and 1152 parts of propylene oxide were introduced at 120 ° C. so that the gauge pressure was 1 to 3 kgf / cm ² . After reacting at 120 ° C. for 8 hours, 40 parts of “KYOWARD 600” is added to the reaction product, the catalyst is adsorbed at 80 ° C., and oxyethylene and oxypropylene groups are random in the side chain by filtration. A polyamide (A-3) having a group was obtained. The number average molecular weight Mn of (A-3) was 8,840. The weight of the oxyalkylene group portion was 53%.
Subsequently, 5 parts of (A-3), 80 parts of ethylene glycol, and 20 parts of 1,6-decanedicarboxylic acid ammonium salt were mixed at room temperature to prepare an electrolytic solution.

Example 4
232 parts of pentaethylenehexamine (trade name: manufactured by PEHA Tosoh Corp.) and 2.0 parts of potassium hydroxide were charged into a stainless steel autoclave having a stirring and temperature control function, and the inside of the mixed system was replaced with nitrogen. At 20 ° C., 1420 parts of ethylene oxide and 355 parts of propylene oxide were introduced so that the gauge pressure was 1 to 3 kgf / cm ² .
After reacting at 120 ° C. for 8 hours, 40 parts of “KYOWARD 600” is added to the reaction product, the catalyst is adsorbed at 80 ° C., and oxyethylene and oxypropylene groups are random in the side chain by filtration. A polyalkylene polyamine (A-4) having a group was obtained. The number average molecular weight Mn of (A-4) was 2,000. The weight of the oxyalkylene group part was 89%.
Then, 5 parts of (A-4), 80 parts of ethylene glycol, and 20 parts of 1,6-decanedicarboxylic acid ammonium salt were mixed to prepare an electrolytic solution.

Example 5
696 parts of pentaethylenehexamine (trade name: manufactured by PEHA Tosoh Corp.) and 336 parts of hexamethylene diisocyanate (trade name: Duranate 50M manufactured by Asahi Kasei Kogyo Co., Ltd.) are charged into a stainless steel autoclave with stirring and temperature control. After replacing the system with nitrogen, the reaction was carried out at 20 ° C. for 4 hours until the isocyanate content became 0.1% or less.
Next, 2.0 parts of potassium hydroxide was added, and at 120 ° C., 1420 parts of ethylene oxide and 355 parts of propylene oxide were introduced so that the gauge pressure would be 1 to 3 kgf / cm ² .
After reacting at 120 ° C. for 8 hours, 40 parts of “KYOWARD 600” is added to the reaction product, the catalyst is adsorbed at 80 ° C., and oxyethylene and oxypropylene groups are random in the side chain by filtration. A polyurethane (A-5) having a group was obtained. The number average molecular weight Mn of (A-5) was 2,800. The weight of the oxyalkylene group portion was 63%.
Next, 5 parts of (A-5), 80 parts of ethylene glycol and 20 parts of 1,6-decanedicarboxylic acid ammonium salt were mixed at room temperature to prepare an electrolytic solution.

Example 6
In a stainless steel autoclave with stirring and temperature control function, 696 parts of pentaethylenehexamine (trade name: PEHA manufactured by Tosoh Corporation), “SR-16H” (1,6-hexanediol diglycidyl ether: manufactured by Sakamoto Pharmaceutical Co., Ltd.) ) After 460 parts were charged and the inside of the mixed system was replaced with nitrogen, the reaction was carried out at 120 ° C. for 12 hours until the reaction rate of the epoxy group reached 99% or more by NMR.
Next, 2.0 parts of potassium hydroxide was added, and at 120 ° C., 1420 parts of ethylene oxide and 355 parts of propylene oxide were introduced so that the gauge pressure would be 1 to 3 kgf / cm ² .
After reaction at ℃ for 40 hours, 40 parts of “KYOWARD 600” was added to the reaction product, and the catalyst was adsorbed at 80 ℃. After filtration, random oxyalkylene groups of oxyethylene and oxypropylene groups were added to the side chain by filtration. An epoxy resin (A-6) was obtained. The number average molecular weight Mn of (A-6) was 2,900. Of these, the weight of the oxyalkylene group portion was 61%.
Next, 5 parts of (A-6), 80 parts of ethylene glycol and 20 parts of 1,6-decanedicarboxylic acid ammonium salt were mixed at room temperature to prepare an electrolytic solution.

Comparative Example 1
A polyamide was synthesized in the same manner as in Example 1.
Next, 2.0 parts of potassium hydroxide was added, and at 120 ° C., 500 parts of ethylene oxide and 100 parts of propylene oxide were introduced so that the gauge pressure was 1 to 3 kgf / cm 2. After reacting at 120 ° C. for 8 hours, 40 parts of “KYOWARD 600” is added to the reaction product, the catalyst is adsorbed at 80 ° C., and oxyethylene and oxypropylene groups are random in the side chain by filtration. A polyamide (A-7) having a group was obtained. The number average molecular weight Mn of (A-7) was 2,450. The weight of the oxyalkylene group portion was 25%.
Thereafter, 5 parts of (A-7), 80 parts of ethylene glycol and 20 parts of 1,6-decanedicarboxylic acid ammonium salt were mixed at room temperature to prepare an electrolytic solution.
Comparative Example 2
5 parts of “PEG4000N” (polyethylene glycol: manufactured by Sanyo Kasei Kogyo Co., Ltd.) adsorbed and removed with “Kyoward 600”, 80 parts of ethylene glycol, 20 parts of 1,6-decanedicarboxylic acid ammonium salt at room temperature An electrolyte was prepared by mixing.

Comparative Example 3
5 parts of “PEG1000” (polyethylene glycol: manufactured by Sanyo Chemical Industries) with “Kyoward 600” adsorbed and removed, 80 parts of ethylene glycol, 20 parts of 1,6-decanedicarboxylic acid ammonium salt at room temperature An electrolyte was prepared by mixing.

Comparative Example 4
An electrolytic solution was prepared by mixing 80 parts of ethylene glycol and 20 parts of 1,6-decanedicarboxylic acid ammonium salt at room temperature.

  About the electrolyte solution created in Examples 1-6 and Comparative Examples 1-4, the electrical conductivity in 30 degreeC and the spark voltage in 30 degreeC were measured with the following method, and the result of Table 1 was obtained.

<Initial specific conductivity at 30 ° C.>
The electrical conductivity at 30 ° C. of the electrolytic solution was measured using a specific conductivity measuring device (manufactured by Toa Denpa Kogyo Co., Ltd .: CM-40S).
<Spark voltage at 30 ° C>
The discharge voltage of the electrolytic solution when a constant current method (2 mA) was loaded was measured using a 10 cm ² high-pressure chemical etching aluminum foil.

  As is clear from Table 1, the electrolytic solutions of Examples 1 to 6 are superior in the withstand voltage characteristics as compared with the electrolytic solutions of Comparative Examples 1 to 3, and have higher electrical conductivity than Comparative Examples 1 to 4.

(Method for producing aluminum electrolytic capacitor)
The electrolytic solutions of Examples 1 to 6 and Comparative Examples 1 and 2 were impregnated into a wound aluminum electrolytic capacitor element having a constant voltage of 6.3 V and a capacitance of 1000 μF, and the capacitor element was put into an outer case of φ10 × 12.5L. After enclosing, the opening of the outer case was curled together with the sealing material to produce the electrolytic capacitor of the present invention.

  About the aluminum electrolytic capacitor using the electrolyte solution of Examples 1-6 and Comparative Examples 1-4, 400V was applied at 110 degreeC for 1 hour, aging operation was performed, and the result of Table 2 was obtained.

  As apparent from Table 2, the aluminum electrolytic capacitors using the electrolytic solutions of Comparative Examples 1 to 3 were short-circuited during aging. On the other hand, the aluminum electrolytic capacitors using the electrolytic solutions of Examples 1 to 6 did not cause a short circuit without causing a problem even during aging.

The electrolytic solution for electrolytic capacitors of the present invention is useful as a capacitor, particularly as an aluminum electrolytic capacitor.

Claims (7)

An electrolytic solution for a capacitor comprising a compound (A) having an oxyalkylene group in a side chain of a polymer main chain containing a nitrogen atom and an electrolyte (B). 2. The electrolytic solution for a capacitor according to claim 1, wherein the polymer main chain is polyamide. The electrolytic solution for a capacitor according to claim 1 or 2, wherein the compound (A) contains a compound represented by the following formula (I) as a main component.
(In the formula, R ¹ is an alkylene group or an alkenylene group; R ² and R ³ are hydrogen or oxyalkylene groups, which may be the same or different; n is an integer of 2 to 20, and m is 1 to An integer of 20 and k is an integer of 1 to 50 on average.) The electrolytic solution for a capacitor according to claim 1, wherein the proportion of the oxyalkylene group is 30 to 99% by weight of (A). The electrolytic solution for a capacitor according to any one of claims 1 to 4, wherein the oxyalkylene group is represented by the following formula (II).
formula
_{- {(C 2 H 4 O} ) p (AO) q} -H (II)
(In the formula, A is an alkylene group having 3 or more carbon atoms, p is an integer of 1 or more having an average of 1 to 40, q is an integer of 0 or 1 having an average of 0 to 40, and (p + q) is It is an integer greater than or equal to 1 with an average of 1 to 80. {(C ₂ H ₄ O) _p (AO) _q } represents block addition or random addition when q ≠ 0. Is not limited.) A capacitor using the electrolytic solution for a capacitor according to claim 1. The capacitor according to claim 6, wherein the capacitor is an aluminum electrolytic capacitor.