JP2017004984A - Solid electrolyte additive for solid electrolytic capacitor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a solid electrolyte additive for a solid electrolytic capacitor which can keep internal resistance of a solid electrolyte layer and improve voltage endurance thereof, and a solid electrolytic capacitor using the same.SOLUTION: A solid electrolytic capacitor with an electric conductive coating film is manufactured by using: a solid electrolyte additive (A) for the solid electrolytic capacitor including a boric acid ester (H); and a solid electrolyte composition for the solid electrolytic capacitor including the additive (A), π conjugated polymer compound (B) and a solvent (C2) or a solid electrolyte precursor composition for the solid electrolytic capacitor including the additive (A) and a precursor monomer (b) of the π conjugated polymer compound.SELECTED DRAWING: None

Description

  The present invention relates to an additive added to a solid electrolyte for a solid electrolytic capacitor.

  In recent years, there is an increasing need for flexibility in electronic materials, and application of conductive polymers such as polyaniline and polypyrrole to conductive functional materials, charge transport materials, and optical functional materials has been actively studied. In particular, conductive functional materials have been put to practical use as electrolytes for solid electrolytic capacitors and antistatic agents. In order to expand the practicality of these conductive polymers, further improvements in conductivity and workability have been attempted. In addition, these conductive polymer compounds are required to have a high guaranteed voltage as the operating voltage increases.

  In the field of capacitors, for the purpose of reducing impedance in the high frequency region, an oxide film (dielectric film) such as aluminum, tantalum, or niobium is etched to form a porous film, and polypyrrole, polyaniline, or the like is formed on this surface. A conductive polymer capacitor is used in which a layer (conductive polymer layer) made of π-conjugated polymer is used as a cathode.

  In Patent Document 1, a coating solution of a solution or a dispersion in which phosphoric acid or a phosphate ester is added to a polypyrrole aqueous solution or a polyaniline aqueous solution is proposed, and the withstand voltage of a solid electrolytic capacitor using this solution or the dispersion coating solution is proposed. It has been improved.

Patent Document 2 proposes a coating solution of a solution or a dispersion in which a fluorosurfactant is added to a polypyrrole aqueous solution or a polyaniline aqueous solution. Similarly to Patent Document 1, a solid electrolytic solution using this solution or a dispersion coating solution is proposed. The withstand voltage of the capacitor has been improved. However, in Patent Document 1 and Patent Document 2, although the withstand voltage is improved, the adhesion to the substrate is insufficient, and there is room for improvement in the internal resistance of the conductive polymer layer.

JP 2001-155964 A JP 2001-283655 A

  The present invention has been made in view of the above problems, and the present invention is for a solid electrolyte for a solid electrolytic capacitor capable of increasing the withstand voltage of the solid electrolyte layer while maintaining the internal resistance of the solid electrolyte layer. An object is to provide an additive and a solid electrolytic capacitor using the additive.

As a result of intensive studies to achieve the above object, the present inventors have reached the present invention.
That is, the present invention provides a solid electrolyte additive (A) for a solid electrolytic capacitor containing a borate ester (H);
A solid electrolyte composition for a solid electrolytic capacitor containing the additive (A), a π-conjugated polymer compound (B) and a solvent (C2); the additive (A) and a precursor monomer for the π-conjugated polymer compound A solid electrolyte precursor composition for a solid electrolytic capacitor containing (b); formed by using the solid electrolyte composition for a solid electrolytic capacitor or by polymerizing the solid electrolyte precursor composition for a solid electrolytic capacitor A conductive film for a solid electrolytic capacitor; a solid electrolytic capacitor having the conductive film for a solid electrolytic capacitor.

  The solid electrolyte additive for solid electrolytic capacitors of the present invention can produce a solid electrolytic capacitor having a high withstand voltage while maintaining internal resistance.

The solid electrolytic capacitor of the present invention, which has a high withstand voltage, comprises the solid electrolyte composition for a solid electrolytic capacitor of the present invention or is obtained by polymerizing the precursor composition for a solid electrolyte of the present invention. This feature is manifested by having a conductive film for a solid electrolytic capacitor. The solid electrolyte composition for solid electrolytic capacitors is characterized by containing the solid electrolyte additive (A) for solid electrolytic capacitors of the present invention in addition to the π-conjugated polymer compound (B) and the solvent (C2). is there. The solid electrolyte precursor composition for a solid electrolytic capacitor contains the solid electrolyte additive (A) for a solid electrolytic capacitor of the present invention in addition to the precursor monomer (b) of the π-conjugated polymer compound. It is a feature.
The solid electrolyte additive (A) for a solid electrolytic capacitor of the present invention contains a boric acid ester (H). By including borate ester (H) in the solid electrolyte, when a defect occurs on the anode surface of the solid electrolytic capacitor, borate ester (H) efficiently releases hydroxide ions at the dielectric defect. Thus, it is presumed that the withstand voltage can be increased while maintaining the internal resistance of the electrolyte in order to promote the repair reaction of the defective portion.

Boric acid ester (H) reacts polyhydric alcohol (F1) having 2 to 10 carbon atoms and / or monohydric alcohol (F2) having 1 to 10 carbon atoms and boric acid under the following reaction conditions, for example. The reaction mixture obtained in this way. The reaction product is a mixture of many kinds of compounds and is difficult to describe accurately in terms of composition. Hereinafter, (F1), (F2) or a mixture of (F1) and (F2) may be referred to as alcohol (F).
Reaction conditions: Boric acid and alcohol (F) are mixed, and the mixture is heated to 60 to 90 ° C. and gradually depressurized to 4.0 to 6.0 kPa for dehydration to carry out an esterification reaction. After reaching the target pressure, the esterification reaction is further performed by heating to 100 to 110 ° C. The boric acid ester (H) can be obtained by reacting at 4.0 to 6.0 kPa until the water and low-boiling components are distilled off.

  The equivalent ratio of boric acid to alcohol (boric acid / alcohol) is 1 / 0.1 to 1/3, more preferably 1 / 0.2 to 1 / 1.5.

  The boron content contained in the boric acid ester (H) is preferably 7 to 16% by weight, more preferably 9 to 13% by weight. When the boron content in the borate ester (H) is 7% by weight or more, the effect of suppressing the occurrence of a sudden short circuit is great. When the boron content in the borate ester (H) is 16% by weight or less, the solvent solubility is good.

The boron content in the borate ester (H) can be measured by the following method.
The sample was weighed (Sg) in a 100 mL beaker, 50 mL of glycerin solution (glycerin: ion-exchanged water = equal volume) was added, and potentiometric titration was performed with 0.1 mol / L caustic potash standard solution. The titer (AmL) of 1 mol / L caustic potash standard solution is determined. Calculated by the following formula, the average value when the difference between two or more test results agrees within 0.2% as the boron content is obtained up to the first decimal place.
Boron content (% by weight) = {(A × f × 1.08) / (S × 1000)} × 100
Here, f represents the titer of 0.1 mol / L caustic potash standard solution.

Examples of the polyhydric alcohol (F1) having 2 to 10 carbon atoms (hereinafter sometimes referred to as C) include the following.
(1) Divalent alcohol diethylene glycol, triethylene glycol, tetraethylene glycol, pentaethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, 1,3-butylene glycol, 2,3-butylene glycol, and the like.
(2) Trivalent or higher alcohol glycerol, 1,2,3-butanetriol, 1,2,4-butanetriol, 1,2,5-pentanetriol, 1,2,3-cyclohexanetriol, 1,3, 5-cyclohexanetriol, 1,2,6-cyclohexanetriol, 3-methylpentane-1,3,5-triol, 1,2,3,4-butanetetraol, erythritol, ribitol and the like.

Examples of the monohydric alcohol (F2) having 1 to 10 carbon atoms include alkanol (which may contain an aromatic ring), (poly) alkylene glycol (C is 2 to 9) monoalkyl (C is 1 to 8) Ether.
Specific examples include the following.
(3) Monohydric alcohol (a) Alkanol methyl alcohol, ethyl alcohol, 1-propyl alcohol, 2-propyl alcohol, 1-butyl alcohol, 2-butyl alcohol, t-butyl alcohol, 1-pentyl alcohol, 2-pentyl Alcohol, 3-pentyl alcohol, 1-hexyl alcohol, 2-hexyl alcohol, 3-hexyl alcohol, heptyl alcohol, octyl alcohol, nonyl alcohol, decyl alcohol, benzyl alcohol and the like.
(B) (Poly) alkylene glycol monoalkyl ether, ethylene glycol monomethyl ether, ethylene glycol monopropyl ether, ethylene glycol monobutyl ether, ethylene glycol monopentyl ether, ethylene glycol monohexyl ether, ethylene glycol monoheptyl ether, ethylene glycol monooctyl ether , Diethylene glycol monomethyl ether, diethylene glycol monopropyl ether, diethylene glycol monobutyl ether, triethylene glycol monomethyl ether, triethylene glycol monobutyl ether, propylene glycol monomethyl ether, propylene glycol monobutyl ether, dipropylene glycol monomethyl ether, dipropylene Such as glycol mono-butyl ether.

  (F1) and (F2) may be used alone or in combination of two or more. From the viewpoint of solvent solubility when becoming a borate ester, (F1) is preferably alkylene (C is 2 to 10) glycol, and (F2) is alkylene (C is 2 to 9) glycol monoalkyl (C is 1-8) Ether is preferred. Further, (F1) is particularly preferably diethylene glycol or triethylene glycol, and (F2) is particularly preferably diethylene glycol monomethyl ether or triethylene glycol monomethyl ether.

  When the number of carbon atoms of the alcohol (F) exceeds 10, when the boric acid ester is formed, the viscosity becomes high, which is not preferable because handling becomes difficult.

  The additive (A) of the present invention contains a boric acid ester (H), but can further contain a solvent (C1). Examples of the solvent include the following (C11) to (C18) and mixtures thereof.

Alcohol (C11)
Examples of the monohydric alcohol include alkanols (which may include an aromatic ring) similar to those exemplified for the monohydric alcohol (F2), (poly) alkylene glycol (C is 2 to 9) monoalkyl (C is 1-8) ether. Examples of the polyhydric alcohol include polyhydric alcohols having 2 to 10 carbon atoms similar to those exemplified for the polyhydric alcohol (F1) and tetrahydric or higher alcohols (eg, hexitol).

Ethers (C12)
Monoether (ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monophenyl ether, tetrahydrofuran, 3-methyltetrahydrofuran, etc.), diether (ethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, 1 , 3-dioxolane, etc.), triethers (diethylene glycol dimethyl ether, diethylene glycol diethyl ether, etc.) and the like.

Amides (C13)
Acetamide (N-methylacetamide, N, N-dimethylacetamide, N-ethylacetamide, N, N-diethylacetamide, etc.), propionamide (N, N-dimethylpropionamide, etc.), pyrrolidone (N-methylpyrrolidone, N- Ethyl pyrrolidone, etc.), hexamethylphosphorylamide, etc.

Lactones (C14)
γ-butyrolactone, α-acetyl-γ-butyrolactone, β-butyrolactone, γ-valerolactone, δ-valerolactone, and the like.

Nitriles (C15)
Acetonitrile, propionitrile, butyronitrile, acrylonitrile, methacrylonitrile, benzonitrile, etc.

Carbonates (C16)
Ethylene carbonate, propylene carbonate, butylene carbonate, dimethyl carbonate, diethyl carbonate and the like.

Sulfones (C17)
Sulfolane, dimethyl sulfone and the like.

Other solvents (C18)
Dimethyl sulfoxide, 1,3-dimethyl-2-imidazolidinone, aromatic solvents (toluene, xylene, etc.), paraffin solvents (normal paraffin, isoparaffin, etc.), water, etc.

  Of the solvents (C1), alcohols (C11), dimethylformamide, N-methylpyrrolidone and dimethyl sulfoxide are preferable. The polyhydric alcohol (F1) having 2 to 10 carbon atoms and a mixture thereof are more preferred, and among these, a polyhydric alcohol having a boiling point of 300 ° C. or lower and a mixture thereof are more preferred. When the boiling point is 300 ° C. or lower, almost no solvent remains in the conductive film in the conductive film forming step, and the characteristics of the conductive film are hardly adversely affected. Particularly preferred are diethylene glycol, triethylene glycol and mixtures thereof.

  In the additive (A), the content of the boric acid ester (H) is preferably 10 to 50 with respect to the total weight of the boric acid ester (H) and the solvent (C1) when the solvent (C1) is contained. % By weight, more preferably 10 to 30% by weight.

  The solid electrolyte composition for a solid electrolytic capacitor of the present invention contains an additive (A) for a solid electrolyte for a solid electrolytic capacitor, a π-conjugated polymer compound (B), and a solvent (C2).

  Examples of the π-conjugated polymer compound (B) include known π-conjugated polymer compounds (for example, polyaniline derivatives (polyaniline and substituted polyaniline), polypyrrole derivatives (polypyrrole and substituted polypyrrole), polythiophene derivatives (polythiophene and Substituted polythiophene), polyacetylene derivatives (polyacetylene and substituted polyacetylene) and polyisothianaphthene derivatives (polyisothianaphthene and substituted polyisothianaphthene)) and the like can be used. From the viewpoint of solvent solubility, preferred are polyaniline derivatives and polypyrrole derivatives, and more preferred are substituted polyaniline and substituted polypyrrole.

Examples of the substituent include linear or branched alkyl groups having 1 to 20 carbon atoms [for example, methyl group, ethyl group, n- or iso-propyl group, n-, iso-, sec- or tert-butyl group. N- or iso-pentyl group, n- or iso-hexyl group, n- or iso-heptyl group, n- or iso-octyl group, 2-ethylhexyl group, n- or iso-nonyl group, n- or iso -Decyl, n- or iso-undecyl, n- or iso-dodecyl, n- or iso-tridecyl, n- or iso-tetradecyl, n- or iso-pentadecyl, n- or iso-hexadecyl Group, n- or iso-heptadecyl group, n- or iso-octadecyl group, n- or iso-nonadecyl group, n- or iso-icosyl group and the like] Linear or branched alkoxy group having 1 to 20 carbon atoms [e.g., methoxy group, ethoxy group, propoxy group, isopropoxy group, n-, iso-, sec- or tert-butoxy group, pentyloxy group, hexyloxy group , Heptyloxy group, octyloxy group, 2-ethylhexyloxy group, nonyloxy group, decyloxy group, undecyloxy group, dodecyloxy group, tridecyloxy group, tetradecyloxy group, pentadecyloxy group, hexadecyloxy group, Heptadecyloxy group, octadecyloxy group, nonadecyloxy group, icosyloxy group, etc.], C 1-20 polyether group [eg, 1,3-dioxopentyl group, 2,5-dioxaheptyl group, 2,5 , 8-Trioxaoctyl group, 1,4,7,10-tetraoxau Decyl, 1,4,7,10,13,16,19- hepta Oki Psycho sill group, an acidic group _{^{[e.g., -SO 3 -, -SO 3 H}} , -R 1 SO 3 -, -R 1 _{^{SO 3 H, -COO -, -COOH}} , -R 1 COO -, -R 1 COOH or the like. (Wherein R ¹ represents an alkylene group having 1 to 20 carbon atoms, an arylene group having 1 to 20 carbon atoms or an aralkylene group having 1 to 20 carbon atoms)], an amino group [for example, —NH ₂ , — _{^{NHR 2, -N (R 2)}} 2 and the like. (Wherein R ² represents an alkyl group having 1 to 20 carbon atoms, an aryl group having 1 to 20 carbon atoms, or an aralkyl group having 1 to 20 carbon atoms)], an amide group [for example, —NHCOR ² or the like. (Wherein R ² represents an alkyl group having 1 to 20 carbon atoms, an aryl group having 1 to 20 carbon atoms or an aralkyl group having 1 to 20 carbon atoms)], an ester group [for example, —COOR ² , — OCOR ² etc. (Wherein R ² represents an alkyl group having 1 to 20 carbon atoms, an aryl group having 1 to 20 carbon atoms, or an aralkyl group having 1 to 20 carbon atoms)], a thioether group [for example, —SR ² or the like. (Wherein R ² represents an alkyl group having 1 to 20 carbon atoms, an aryl group having 1 to 20 carbon atoms, or an aralkyl group having 1 to 20 carbon atoms)], hydroxyl group, nitro group, nitrile group, aldehyde group And halogen groups [-F, -Cl, -Br, -I, etc.] and the like. Among these, from the viewpoint of solvent solubility, a linear or branched alkyl group having 1 to 20 carbon atoms, a linear or branched alkoxy group having 1 to 20 carbon atoms, or a polyoxygen having 1 to 20 carbon atoms is preferable. An ether group and an acid group.

  The π-conjugated polymer compound (B) can be obtained by polymerizing monomers as raw materials. The polymerization can be performed by a known method such as anionic polymerization or oxidative polymerization.

  Examples of the raw material monomer for the π-conjugated polymer compound include compounds having a pyrrole skeleton and an aniline skeleton. For example, 3-alkyl group-substituted pyrrole such as 3-n-hexylpyrrole and 3-n-dodecylpyrrole, 3-alkoxy group-substituted pyrrole such as 3-methoxypyrrole and 3-heptyloxypyrrole, 3- (1,3- Dietherpentyl) pyrrole, 3-polyether group-substituted pyrrole such as 3- (1,4,7,10-tetraoxaundecyl) pyrrole, 3- (3-pyrrolyl) -propane-1-sulfonic acid, 4- Alkylsulfonic acid group-substituted pyrrole such as (3-pyrrolyl) -butane-1-sulfonic acid, 6- (3-pyrrolyl) -hexane-1-sulfonic acid, o-, m- or p-aminobenzenesulfonic acid, aniline Sulfonic acid group-substituted anilines such as 2,6-disulfonic acid and methylaminobenzenesulfonic acid, and o-, m- or p-aminobenzenecarbo Acid, aniline-2,6-dicarboxylic acid, and a carboxy group-substituted aniline such as methylamino benzene carboxylic acids. These may be used alone or in combination of two or more.

  As the solvent (C2), a solvent in which the additive for solid electrolyte for solid electrolytic capacitor (A) and the π-conjugated polymer compound (B) can be dissolved or dispersed well is desired. And the same solvent. Of the solvents (C2), those having a boiling point of 300 ° C. or lower and mixtures thereof are preferred. When the boiling point is 300 ° C. or lower, almost no solvent remains in the conductive film in the conductive film forming step, and the characteristics of the conductive film are hardly adversely affected. For example, methyl alcohol, ethyl alcohol, 1-propyl alcohol, 2-propyl alcohol, 1-butyl alcohol, ethylene glycol, diethylene glycol, triethylene glycol, dimethylformamide, γ-butyrolactone, 1,3-dioxolane, N-methylpyrrolidone, Examples thereof include dimethyl sulfoxide, water, and a mixture thereof.

  In the solid electrolyte composition of the present invention, the content of the solid electrolyte additive (A) for the solid electrolytic capacitor is preferably from the viewpoint of the withstand voltage improvement effect with respect to the weight of the π-conjugated polymer compound (B). The content is more preferably 50 to 3000% by weight and more preferably 100 to 2000% by weight from the viewpoint of suppressing the increase in internal resistance. The boric acid ester (H) is preferably 5 to 300% by weight, more preferably from the viewpoint of suppressing an increase in internal resistance, with respect to the weight of the π-conjugated polymer compound (B). It is contained in an amount of 10 to 200% by weight.

  The content of the π-conjugated polymer compound (B) is selected from the viewpoints of the film formability of the conductive film and the solubility or dispersibility in the solvent (C2), the solid electrolyte additive for solid electrolytic capacitors (A), The content is preferably 0.1 to 20% by weight based on the total weight of the π-conjugated polymer compound (B) and the solvent (C2).

  The solid electrolyte composition for a solid electrolytic capacitor can be obtained by dissolving (A) in a solution in which (B) is dissolved or dispersed in (C2). Alternatively, a solution obtained by dissolving (A) in (C2) and a solution obtained by dissolving or dispersing (B) in (C2) may be mixed. Examples of the method of dissolving or dispersing include a method of stirring at room temperature using a normal vertical stirring blade.

If necessary, a dopant can be further added to the solid electrolyte composition for a solid electrolytic capacitor of the present invention.
Examples of the dopant include inorganic acids (such as sulfuric acid, nitric acid, phosphoric acid and condensed phosphoric acid), halogen ions (such as iodine, bromine and chlorine), halide ions (such as tetrafluoroboron and perchloric acid), and quinones. Compounds [chloranilic acid, p-chloranil, p-benzoquinone, p-quinonedioxime, dichlorodicyanoquinone (DDQ), p-naphthoquinone, anthraquinone, chloroanthraquinone, p-toluquinone, etc.], alkyl-substituted organic sulfonate ions (methane Sulfonic acid and dodecyl sulfonic acid), cyclic sulfonic acid ions (camphor sulfonic acid ion, etc.), alkyl-substituted or unsubstituted benzene mono- or disulfonic acid ions (benzene sulfonic acid, paratoluene sulfonic acid, dodecyl benzene sulfonic acid and Benzene disulfonic acid ), Alkyl substituted ions or unsubstituted ions of naphthalenesulfonic acid having 1 to 4 sulfonic acid groups (such as 2-naphthalenesulfonic acid and 1,7-naphthalenedisulfonic acid), anthracenesulfonic acid ion, anthraquinonesulfonic acid ion , Alkyl-substituted or unsubstituted biphenyl sulfonic acid ions (alkyl biphenyl sulfonic acid and biphenyl disulfonic acid, etc.), substituted or unsubstituted aromatic polymer sulfonic acid ions (polystyrene sulfonic acid and naphthalene sulfonic acid formalin condensate, etc.) And sulfur trioxide complex.

  The sulfur trioxide complex is a complex of sulfur trioxide and a Lewis base such as ether, amide, amine, or sulfide. As ether / sulfur trioxide complex, sulfur trioxide dioxane complex, sulfur trioxide dioxolane complex, sulfur trioxide dimethyl ether complex, sulfur trioxide ethyl methyl ether complex, sulfur trioxide diethyl ether complex, etc. Sulfur trioxide N, N-dimethylformamide complex, etc. As amine / sulfur trioxide complex, sulfur trioxide pyridine complex, sulfur trioxide triethylamine complex, sulfur trioxide trimethylamine complex, sulfur trioxide N-ethyldiisopropylamine complex, sulfide -As a sulfur trioxide complex, a sulfur trioxide dimethyl sulfide complex, a sulfur trioxide ethylmethyl sulfide complex, a sulfur trioxide diethyl sulfide complex, etc. are mentioned. Of these, amide / sulfur trioxide complexes and amine / sulfur trioxide complexes are preferable from the viewpoint of conductivity. Among amide / sulfur trioxide complexes, sulfur trioxide N, N-dimethylformamide complexes, amine / sulfur trioxides are preferred. Of the sulfur complexes, sulfur trioxide pyridine complexes are preferred. Among the above, as a dopant, from the viewpoint of conductivity, an inorganic acid, an alkyl-substituted organic sulfonate ion, a cyclic sulfonate ion, an alkyl-substituted or unsubstituted benzene mono- or disulfonate ion, or a sulfonate group is 1 Preferred are alkyl-substituted ions or unsubstituted ions, alkyl-substituted or unsubstituted biphenyl sulfonate ions, substituted or unsubstituted aromatic polymer sulfonate ions or sulfur trioxide complexes of ~ 4 naphthalene sulfonates. Of these, sulfuric acid, phosphoric acid, condensed phosphoric acid, paratoluenesulfonic acid, dodecylbenzenesulfonic acid, 2-naphthalenesulfonic acid, polystyrenesulfonic acid, and sulfur trioxide N, N-dimethylformamide complex are more preferable.

The π-conjugated polymer compound (B) donates electrons to the dopant and forms a charge transfer complex together with the dopant.
Since this charge transfer complex exhibits conductivity as an electron carrier, it is preferable that the dopant concentration is high, but if it is excessive, the conductivity is lowered. Therefore, the usage-amount of a dopant has preferable 5 to 1000 weight% with respect to (pi) conjugated polymer compound (B), More preferably, it is 10 to 800 weight%.

  The precursor composition for a solid electrolyte for a solid electrolytic capacitor of the present invention contains a solid electrolyte additive (A) for a solid electrolytic capacitor and a precursor monomer (b) of a π-conjugated polymer compound.

  As a precursor monomer (b) of a π-conjugated polymer compound, a known precursor monomer of a π-conjugated polymer compound, for example, an aniline derivative (aniline and substituted aniline), a pyrrole derivative (pyrrole and substituted) Pyrrole), thiophene derivatives (thiophene and substituted thiophenes), acetylene derivatives (acetylene and substituted acetylenes), isothianaphthene derivatives (isothianaphthene and substituted isothianaphthenes), and the like. From the viewpoints of conductivity and solvent solubility, aniline derivatives and pyrrole derivatives are preferred.

  Examples of the substituent include the same substituents as those exemplified for the substituent of the π-conjugated polymer compound. Among these, from the viewpoint of solvent solubility, a linear or branched alkyl group having 1 to 20 carbon atoms, a linear or branched alkoxy group having 1 to 20 carbon atoms, or a polyoxygen having 1 to 20 carbon atoms is preferable. An ether group and an acid group.

  Specific examples of the precursor monomer (b) of the π-conjugated polymer compound include aniline, pyrrole, and monomers similar to those exemplified for the raw material monomer of the π-conjugated polymer compound. These may be used alone or in combination of two or more.

  In the precursor composition for a solid electrolyte of the present invention, the content of the solid electrolyte additive (A) for a solid electrolytic capacitor is a withstand voltage with respect to the weight of the precursor monomer (b) of the π-conjugated polymer compound. The content is preferably 50 to 3000% by weight from the viewpoint of the improvement effect, and more preferably 100 to 2000% by weight from the viewpoint of suppressing the increase in internal resistance. Further, the boric acid ester (H) is preferably 5 to 300% by weight from the viewpoint of the effect of improving the withstand voltage with respect to the weight of the precursor monomer (b) of the π-conjugated polymer compound, from the viewpoint of suppressing an increase in internal resistance More preferably, it is contained in an amount of 10 to 200% by weight.

  If necessary, a solvent (C3) can be further used in the solid electrolyte precursor composition for a solid electrolytic capacitor of the present invention. As the solvent (C3), a solvent in which the solid electrolyte additive (A) for a solid electrolytic capacitor and the precursor monomer (b) of the π-conjugated polymer compound can be dissolved well is desired, and exemplified by the solvent (C1). Examples of the solvent are the same as those described above. Of the above solvents (C3), those having a boiling point of 300 ° C. or lower and mixtures thereof are preferred. When the boiling point is 300 ° C. or lower, almost no solvent remains in the conductive film in the conductive film forming step, and the characteristics of the conductive film are hardly adversely affected. For example, methyl alcohol, ethyl alcohol, 1-propyl alcohol, 2-propyl alcohol, 1-butyl alcohol, ethylene glycol, diethylene glycol, triethylene glycol, dimethylformamide, γ-butyrolactone, 1,3-dioxolane, N-methylpyrrolidone, Examples thereof include dimethyl sulfoxide, water, and a mixture thereof.

  The content of the precursor monomer (b) of the π-conjugated polymer compound is selected from the viewpoints of the film formability of the conductive film and the solubility in the solvent (C3) (A). The π-conjugated polymer compound precursor monomer (b) and the solvent (C3) are preferably contained in an amount of 0.1 to 80% by weight, more preferably 1 to 60% by weight.

  A solid electrolyte precursor composition for a solid electrolytic capacitor is obtained by mixing (A) and (b) or by dissolving (A) in a solution obtained by dissolving (b) in (C3). Can do. Alternatively, a solution obtained by dissolving (A) in (C3) and a solution obtained by dissolving (b) in (C3) may be mixed. Examples of the method for dissolving include a method of stirring at room temperature using a normal vertical stirring blade.

  The conductive film for a solid electrolytic capacitor of the present invention can be obtained by applying the solid electrolyte composition for a solid electrolytic capacitor of the present invention to a substrate (or immersing the substrate in the solid electrolyte composition) and then performing a heat treatment as necessary. It can be produced by removing the solvent.

  The conductive coating for a solid electrolytic capacitor of the present invention is a π-conjugated polymer obtained by applying the solid electrolyte precursor composition for a solid electrolytic capacitor of the present invention to a substrate (or immersing the substrate in the solid electrolyte composition). It can be produced by polymerizing the monomer (b) (oxidation polymerization) and performing a heat treatment as necessary. The polymerization can be performed by a known method such as anionic polymerization or oxidation polymerization. Furthermore, after mixing the precursor composition for solid electrolyte and the oxidizing agent, the mixture may be applied to the substrate (or the substrate is immersed in the solid electrolyte composition), and heat treatment may be performed as necessary. .

  Examples of the oxidizing agent include known oxidizing agents (for example, peroxodisulfuric acid [peroxodisulfuric acid, ammonium peroxodisulfate, sodium peroxodisulfate, potassium peroxodisulfate, etc.], iron salts [ferric chloride, p-toluenesulfonic acid, etc. Ferric etc.], hydrogen peroxide, lead dioxide etc.) can be used. From the viewpoint of conductivity, peroxodisulfuric acids and iron salts are preferred. These may be used alone or in combination of two or more.

  As the solvent that dissolves the oxidizing agent, a solvent that dissolves the oxidizing agent satisfactorily is desired, and examples thereof include the same solvents as those exemplified for the solvent (C1). Of the above solvents, those having a boiling point of 300 ° C. or lower and mixtures thereof are preferred. When the boiling point is 300 ° C. or lower, almost no solvent remains in the conductive film in the conductive film forming step, and the characteristics of the conductive film are hardly adversely affected. From the viewpoint of solvent solubility, more preferred among these are methyl alcohol, ethyl alcohol, 1-propyl alcohol, 2-propyl alcohol, 1-butyl alcohol, ethylene glycol, diethylene glycol, triethylene glycol, dimethylformamide, γ -Butyrolactone, 1,3-dioxolane, N-methylpyrrolidone dimethyl sulfoxide, water and mixtures thereof.

  1-8 mol is preferable with respect to 1 mol of monomers, and, as for the usage-amount of an oxidizing agent, 1-4 mol is more preferable.

  Furthermore, a dopant can be added to the precursor composition for solid electrolyte and / or the oxidizing agent solution as necessary. As a dopant, the dopant similar to what was illustrated with the dopant of the said (pi) conjugated polymer compound is mentioned. Among these, from the viewpoint of conductivity, inorganic acids, alkyl-substituted organic sulfonate ions, cyclic sulfonate ions, alkyl-substituted or unsubstituted benzene mono- or disulfonate ions, and 1 sulfonate group are preferable. Preferred are alkyl-substituted ions or unsubstituted ions, alkyl-substituted or unsubstituted biphenyl sulfonate ions, substituted or unsubstituted aromatic polymer sulfonate ions or sulfur trioxide complexes of ~ 4 naphthalene sulfonates. Of these, sulfuric acid, phosphoric acid, condensed phosphoric acid, paratoluenesulfonic acid, dodecylbenzenesulfonic acid, 2-naphthalenesulfonic acid, polystyrenesulfonic acid, and sulfur trioxide N, N-dimethylformamide complex are more preferable.

  After polymerization, unreacted monomers and / or oxidizing agents may remain in the obtained conductive film, which may adversely affect the properties of the conductive film. Therefore, you may refine | purify the obtained electroconductive film as needed. The purification can be carried out using a washing solvent. As the washing solvent, alcohols such as methanol, ethanol, iso-propanol, n-propanol, and t-butanol, water, and the like can be obtained, which are preferable.

  Examples of a method for forming a conductive film by applying a solid electrolyte composition or a precursor composition for a solid electrolyte to a substrate include a spin coat method, a drop cast method, and a dip coat method. Examples of the substrate include plastic, glass, metal, rubber, ceramics, and paper.

  When producing a conductive film using the solid electrolyte composition or the precursor composition for a solid electrolyte of the present invention, it is necessary to remove the solvent when the solvent is contained therein. In the case of a solvent having a low boiling point, the solvent is removed by natural drying at room temperature or heat drying by circulating drying, but in the case of a solvent having a high boiling point, heat drying by a vacuum dryer is preferable.

  In order to obtain a conductive film having sufficient strength and conductivity, the heat treatment temperature is preferably 50 to 190 ° C, and more preferably 80 to 170 ° C in order to obtain a highly conductive film. It is.

  The heat treatment time is appropriately determined according to the heat treatment temperature, the concentration of the π-conjugated polymer compound in the solid electrolyte composition, or the concentration of the precursor monomer of the π-conjugated polymer compound in the solid composition precursor composition. Although selected, it is usually 0.5 to 8 hours, preferably 1 to 4 hours. By setting the heating time to 0.5 hours or longer, a sufficiently conductive film can be obtained from the solid electrolyte composition or the precursor composition for solid electrolyte.

  From the viewpoint of conductivity, the thickness of the conductive film formed on the substrate surface is preferably 0.05 to 100 μm, and more preferably 0.1 to 50 μm. When the film is thickened to 0.05 μm or more, sufficient conductivity can be obtained. On the other hand, if the thickness is 100 μm or less, cracks and peeling are unlikely to occur during formation.

  The conductive film of the present invention formed from the solid electrolyte composition of the present invention or the precursor composition for solid electrolyte can be used as the solid electrolyte of the solid electrolytic capacitor of the present invention. The solid electrolytic capacitor is not particularly limited, and examples thereof include an aluminum electrolytic capacitor (such as a wound aluminum electrolytic capacitor and a laminated aluminum electrolytic capacitor), a tantalum electrolytic capacitor, and a niobium electrolytic capacitor.

  For example, a case where an aluminum electrolytic capacitor using a conductive coating formed from the solid electrolyte composition of the present invention as a solid electrolyte will be described. First, an aluminum etched foil as an anode metal is subjected to chemical conversion treatment, a dielectric film made of an oxide film is formed on the surface of the aluminum etched foil, and an anode made of an anode metal and a dielectric film is produced. Thereafter, the anode is applied or immersed in the solid electrolyte composition of the present invention, pulled up, and then dried at a predetermined temperature to form a conductive film as a solid electrolyte layer. Thereafter, a carbon paste is applied and dried on the obtained solid electrolyte layer, and then a silver paste is further applied and dried to form a cathode. Pull out the lead wire from the silver paste and connect the terminal. An anode terminal is connected to the anode foil. Thereafter, the mold exterior resin is formed so that the ends of the anode terminal and the cathode terminal are drawn out to the outside. An aluminum electrolytic capacitor is produced by the above method.

  A solid electrolytic capacitor using the conductive coating of the present invention as a solid electrolyte is useful because it maintains the internal resistance of the solid electrolyte layer and contains a boric acid ester (H) and is excellent in withstand voltage. .

  Hereinafter, although an example and a comparative example explain the present invention further, the present invention is not limited to these. Hereinafter, a part shows a weight part.

<Production Example 1>: Preparation of aqueous solution of poly [4- (3-pyrrolyl) butanesulfonic acid] (B-1) It is disclosed in Chemistry of Materials magazine (American Chemical Society 1989) Vol. With reference to the method, an aqueous solution of a polypyrrole derivative having a sulfonic acid group was prepared.
84.0 parts of 4-chlorobutyryl chloride [manufactured by Wako Pure Chemical Industries, Ltd.] was dissolved in 100 parts of dichloromethane [manufactured by Wako Pure Chemical Industries, Ltd.], and the solution was dissolved in aluminum (III) chloride [III] Wako Pure Chemical Industries, Ltd.] was added dropwise to a mixture of 75.8 parts and 500 parts of dichloromethane over 20 minutes while cooling with a water bath. After 1 hour, a solution prepared by dissolving 93.2 parts of 1- (phenylsulfonyl) pyrrole (manufactured by Aldrich) in 400 parts of dichloromethane was added dropwise to the previous solution over 30 minutes while cooling in a water bath. . After 1 hour, the reaction mixture was poured into 1500 parts of ion-exchanged water, 800 parts of chloroform [manufactured by Wako Pure Chemical Industries, Ltd.] was added and transferred to a separatory funnel, and the aqueous layer was separated. Further, the organic layer was washed once with 1000 parts of 1M aqueous sodium hydroxide solution and twice with 1000 parts of ion-exchanged water. After adding 500 parts of methanol to the organic layer and separating the lower layer, dichloromethane and chloroform were distilled off.
Subsequently, the residue was dissolved in a mixed solution of 600 parts of toluene [manufactured by Wako Pure Chemical Industries, Ltd.] and 240 parts of distilled water. Add 360 parts of zinc powder [Wako Pure Chemical Industries, Ltd.] to a solution of 30 parts of mercury (II) chloride [Wako Pure Chemical Industries, Ltd.] dissolved in 600 parts of distilled water and occasionally shake The mixture was allowed to react at room temperature for 1 hour while mixing, and 360 parts of zinc amalgam obtained by removing the supernatant by dentation was added to the above solution, and 600 parts of concentrated hydrochloric acid [manufactured by Wako Pure Chemical Industries, Ltd.] was further added. added. The mixture was stirred and reacted for 3 hours under heating to reflux. After completion of the reaction, the reaction mixture was cooled to room temperature, the reaction mixture was transferred to a separatory funnel, and the aqueous layer was separated. Further, the organic layer was washed twice with 600 parts of ion-exchanged water, and toluene was distilled off to obtain 129 parts of oily 1- [1- (phenylsulfonyl) -3-pyrrolyl] -4-chlorobutane.

1- [1- (Phenylsulfonyl) -3-pyrrolyl] -4-chlorobutane obtained above, 26.4 parts of distilled water, 260 parts of distilled water, 100 parts of ethanol [manufactured by Wako Pure Chemical Industries, Ltd.], sodium sulfite [Wako Pure Chemical Industries, Ltd.] 26.3 parts, tetrabutylammonium bromide [Tokyo Chemical Industry Co., Ltd.] 3.0 parts and sodium iodide [Wako Pure Chemical Industries, Ltd.] 3 9 parts were mixed, and the mixture was stirred and reacted for 18 hours under heating to reflux. 26.4 parts of sodium hydroxide was added to the reaction mixture, and the mixture was stirred for 2 hours while heating under reflux. After adding 230 parts of saturated brine and transferring to a separatory funnel using 300 parts of chloroform, the aqueous layer was separated. Further, the organic layer was washed twice with 300 parts of distilled water, the obtained aqueous layer was mixed, and water was distilled off.
Subsequently, 300 parts of distilled water was added to the residue, boiled, and cooled to room temperature. The obtained paste was suction filtered, and the filtrate was washed twice with 40 parts of saturated brine. The obtained solid was added to a mixed solution of 250 parts of ethanol and 10 parts of 2-chloroethanol [manufactured by Aldrich], boiled, and filtered while hot. Ethanol and 2-chloroethanol were distilled off from the filtrate, the residue was added to a mixed solution of 230 parts of ethanol and 4.5 parts of distilled water, boiled, cooled to room temperature, and filtered. The filtrate was cooled to −15 ° C., and the precipitated crystals were filtered, washed with a mixed solution of 9.6 parts of ethanol and 0.4 part of acetone, and 4.5 parts of 4- (3-pyrrolyl) butanesulfone. The acid sodium salt was obtained.

  In a reaction vessel, 4.5 parts of 4- (3-pyrrolyl) butanesulfonic acid sodium salt obtained above, 40 parts of chloroform, and 12.9 parts of iron (III) chloride [manufactured by Wako Pure Chemical Industries, Ltd.] The mixture was stirred at room temperature for 24 hours. After completion of the reaction, 40 parts of methanol was added, and the precipitated solid was collected by filtration. The obtained solid was added to 400 parts of distilled water, and then stirred and dispersed at room temperature for 1 hour. The obtained dispersion was passed through a column packed with 30 parts of an anion exchange resin [AmberJet 4400, manufactured by Organo Corporation], and further, a cation exchange resin [Amberlite 200CT, manufactured by Organo Corporation]. The remaining metal ion component was removed by passing through a column packed with 30 parts to obtain 400 parts of a 1 wt% poly [4- (3-pyrrolyl) butanesulfonic acid] (B-1) aqueous solution.

<Production Example 2>: Synthesis of sulfonated polyaniline A polyaniline derivative having a sulfonic acid group was prepared with reference to JP-A No. 2000-191774. To 3 L of 1.2 mol / L hydrochloric acid aqueous solution, 285 parts of aniline [manufactured by Wako Pure Chemical Industries, Ltd.] was added dropwise and stirred, and this was cooled to 10 ° C. 840 parts of ammonium persulfate [manufactured by Wako Pure Chemical Industries, Ltd.] was dissolved in 1530 parts of ion-exchanged water and added dropwise to the previous solution over 4 hours. After completion of dropping, the mixture was further stirred at 10 ° C. for 20 hours. The deposited green precipitate was filtered, washed with ion-exchanged water until the color of the filtrate disappeared, and further washed with methanol until the color of the filtrate disappeared. Then, it dried for 5 hours with the vacuum dryer hold | maintained at 70 degreeC, and obtained 303 parts of green deposits.

  10.5 parts of the obtained polyaniline hydrochloride was stirred and dispersed in 260 parts of 1,2-dichloroethane [manufactured by Wako Pure Chemical Industries, Ltd.] and heated to 80 ° C. 26.4 parts of chlorosulfuric acid [manufactured by Tokyo Chemical Industry Co., Ltd.] was dissolved in 26 parts of 1,2-dichloroethane and added dropwise over 60 minutes. After completion of dropping, the reaction was further carried out at 80 ° C. for 5 hours. After cooling, the reaction product was filtered off, and the resulting wet cake was stirred and dispersed in 180 parts of a water / 2-propanol = 1/9 mixed solution, and subjected to a hydrolysis reaction at 60 ° C. for 4 hours. After completion of the reaction, the reaction mixture was cooled to room temperature, and the resulting green slurry solution was filtered to obtain a green cake. This was washed with 2-propanol until the filtrate was no longer colored, and 11 parts of a mass-dried product, a sulfonated polyaniline (B-2), which was a green powder, was obtained.

<Production Example 3>: Synthesis of poly (o-methoxyaniline) A polyaniline derivative having a methoxy group was prepared with reference to JP2013-157434A. Take 300 parts of an aqueous solution containing 20.3 parts of o-anisidine [manufactured by Tokyo Chemical Industry Co., Ltd.] and 16.2 parts of concentrated sulfuric acid [manufactured by Wako Pure Chemical Industries, Ltd.]. 120 parts of an aqueous solution containing 45.0 parts of ammonium sulfate was dropped in 75 minutes, and then reacted for 1 hour to obtain an aniline copolymer by chemical oxidative polymerization. Subsequently, after adding 420 parts of 25 mass% ammonia water to the polymerization reaction liquid and stirring for 3 hours, the powder of poly (o-methoxyaniline) (B-3) dedoped by filtering and drying is then obtained. 1 part was obtained.

<Production Example 4>
Boric acid (1.0 mol) and diethylene glycol [Wako Pure Chemical Industries, Ltd.] (F1-1) (0.19 mol) and triethylene glycol monomethyl ether [Wako Pure Chemical Industries, Ltd.] (F2- 1) Mix (0.12 mol), heat to 80 ° C., gradually reduce the pressure to 4.0 kPa for esterification, and further heat to 105 ° C. to distill off the esterification and low boiling point. Thus, borate ester (H-1) was obtained. The boron content of the boric acid ester (H-1) was 12.0% by weight.

<Production Example 5>
Boric acid (0.56 mol), diethylene glycol (F1-1) (0.3 mol) and triethylene glycol monomethyl ether (F2-1) (0.2 mol) are mixed, heated to 80 ° C., and gradually reduced in pressure. The esterification was carried out at 4.0 kPa, and further the esterification and low-boiling components were distilled off by heating to 105 ° C. to obtain a boric acid ester (H-2). The boron content of boric acid ester (H-2) was 7.1% by weight.

<Production Example 6>
Boric acid (0.8 mol) and diethylene glycol (0.8 mol) (F1-1) are mixed, heated to 80 ° C., gradually reduced in pressure to 4.0 kPa, and further esterified to 105 ° C. Thus, borate ester (H-3) was obtained by distilling off the esterification and low boiling point. The boron content of the borate ester (H-3) was 8.2% by weight.

<Examples 1-7>
Π-conjugated polymer compounds (B-1) to (B-3) obtained in Production Examples 1 to 3, polystyrenesulfonic acid aqueous solution as a dopant, borate ester (H--) obtained in Production Examples 4 to 6 1) to (H-3), the solvent (C1), and the solvent (C2) were blended so as to have the blending ratios shown in Table 1. Boric acid ester (H) is dissolved in solvent (C1) to prepare solid electrolyte additive (A), and π-conjugated polymer compound (B) and polystyrene as a dopant immediately before the conductive film production step. A solution of the solid electrolyte composition was prepared by mixing the sulfonic acid aqueous solution, the solid electrolyte additive (A), and the solvent (C2).

Dopant: Polystyrene sulfonic acid aqueous solution [containing 18% polystyrene sulfonic acid, manufactured by Aldrich]
Solvent (C1): Diethylene glycol (C1-1) [manufactured by Wako Pure Chemical Industries, Ltd.], triethylene glycol (C1-2) [manufactured by Wako Pure Chemical Industries, Ltd.]
Solvent (C2): Ultrapure water (C2-1), dimethyl sulfoxide (C2-2) [manufactured by Wako Pure Chemical Industries, Ltd.]

<Comparative Examples 1, 4, 7>
In Examples 1-7, except that the solid electrolyte additive (A) was not added, the solids for comparison were blended so as to have the blending ratios shown in Table 1 in the same manner as in Examples 1-7. A solution of the electrolyte composition was obtained.

<Comparative Examples 2-3, 5-6, 8-9>
Π-conjugated polymer compounds (B-1) to (B-3) obtained in Production Examples 1 to 3, polystyrenesulfonic acid aqueous solution as a dopant, and perfluoroalkyl phosphate ester that is a fluorine-based activator [manufactured by DIC Corporation] Product name: Mega Fuck, Product Number: EXP. TF-2148], orthophosphoric acid [manufactured by Wako Pure Chemical Industries, Ltd.], and solvent (C2) were blended so as to have a blending ratio as shown in Table 1. Immediately before the production process of the conductive film, a π-conjugated polymer compound, a polystyrene sulfonic acid aqueous solution as a dopant, a perfluoroalkyl phosphate ester as a fluorine-based activator, normal phosphoric acid and a solvent (C2) are mixed and compared. A solution of a solid electrolyte composition for use was prepared.

<Examples 8 to 13>
pyrrole (b-1) and aniline (b-2) which are precursor monomers of the π-conjugated polymer compound, boric acid esters (H-1) to (H-3) obtained in Production Examples 4 to 6, And the solvent (C3) were blended so as to have a blending ratio as shown in Table 2. The boric acid ester (H) is dissolved in the solvent (C1) to prepare the solid electrolyte additive (A), and the precursor monomer of the π-conjugated polymer compound, for the solid electrolyte, immediately before the conductive film production step The additive (A) and the solvent (C3) were mixed to prepare a solid electrolyte precursor composition solution. Moreover, p-toluenesulfonic acid which is a dopant, ammonium persulfate which is an oxidizing agent, and a solvent are blended so as to have a blending ratio as shown in Table 2 to prepare a dopant / oxidizer solution of the precursor composition for the solid electrolyte. Obtained.

Precursor monomer of π-conjugated polymer compound: pyrrole (b-1) [manufactured by Tokyo Chemical Industry Co., Ltd.], aniline (b-2) [manufactured by Wako Pure Chemical Industries, Ltd.]
Solvent (C3): Ultrapure water (C3-1)
Ethyl alcohol (C3-2) [Wako Pure Chemical Industries, Ltd.]
Dopant: p-toluenesulfonic acid [manufactured by Tokyo Chemical Industry Co., Ltd.]
Oxidizing agent: ammonium persulfate [Wako Pure Chemical Industries, Ltd.]

<Comparative Examples 10-11>
In Examples 8 to 13, a solid for comparison was formulated in the same manner as in Examples 8 to 13 except that the solid electrolyte additive (A) was not added, so that the blending ratio was as shown in Table 2. A solution of the precursor composition for electrolyte was obtained. Moreover, p-toluenesulfonic acid which is a dopant, ammonium persulfate which is an oxidizing agent, and a solvent are blended so as to have a blending ratio as shown in Table 2 to prepare a dopant / oxidizer solution of the precursor composition for the solid electrolyte. Obtained.

  Using the above solid electrolyte composition, comparative solid electrolyte composition, precursor composition for solid electrolyte, solution of the precursor composition for solid electrolyte for comparison, and dopant / oxidizer solution, the following method is used to conduct electricity. Adhesive film was prepared and the adhesion was evaluated. Moreover, the solid electrolytic capacitor was produced by the following method, and electrostatic capacity, internal resistance, and withstand voltage were evaluated. The results are shown in Tables 1 and 2 above.

[Method for producing conductive film]
The solutions of the solid electrolyte compositions of Examples 1 to 7 and the solutions of the solid electrolyte compositions of Comparative Examples 1 to 9 were applied to a 3 cm × 7 cm rectangular pattern on an aluminum oxide foil using a doctor blade, and 30 at room temperature. After being dried under reduced pressure for a minute, it was heated on a hot plate at 170 ° C. for 15 minutes to obtain a conductive film. Moreover, the mixed solution which added the dopant and oxidizing agent solution to the solution of the precursor composition for solid electrolytes of Examples 8-13 and the solution of the precursor composition for solid electrolytes of Comparative Examples 10-11 was used as the aluminum oxide foil. A 3 cm x 7 cm rectangular pattern was applied to the sample using a doctor blade, dried under reduced pressure at room temperature for 30 minutes, and then heated on a hot plate at 170 ° C for 15 minutes to obtain a conductive film.

[Adhesion evaluation method]
The adhesiveness of the obtained conductive film is evaluated according to a grid cellophane tape peeling test in accordance with JIS K-5400.

[Evaluation method of capacitor characteristics]
(1) Production of dielectric film on anode An aluminum etched foil (size: 4 × 3.3 mm) as an anode metal is immersed in a 3 wt% ammonium adipate aqueous solution, and a constant current constant voltage power supply device is used. After raising from 0 V to 40 V under the condition of 0.53 mA / sec, a constant voltage of 40 V was applied for 40 minutes for chemical conversion treatment to form a dielectric film made of an oxide film on the surface of the aluminum etched foil. This was washed with running deionized water for 10 minutes and then dried at 105 ° C. for 5 minutes to produce an anode composed of an anode metal and a dielectric film.

(2) Preparation of electrode for solid electrolytic capacitor The anode was immersed in the solution of the solid electrolyte composition and the solution of the solid electrolyte composition for comparison, pulled up, dried at room temperature for 30 minutes, and then dried at 170 ° C for 30 minutes. As a result, an electrolyte layer was formed to produce an electrode for a solid electrolytic capacitor. Also, after immersing the anode in the solution of the precursor composition for solid electrolyte and the precursor composition for solid electrolyte for comparison and pulling it up, the anode is immersed in the dopant / oxidizer solution, and π-conjugated system by chemical polymerization method The polymer monomer precursor monomer was polymerized, dried at room temperature for 30 minutes, and then dried at 170 ° C. for 30 minutes to form an electrolyte layer and produce an electrode for a solid electrolytic capacitor.
(3) Production of Electrolytic Capacitor A carbon paste [“Bunny Height FU” manufactured by Nippon Graphite Co., Ltd.] is applied on the electrolyte layer obtained above, dried, and further silver paste [manufactured by Nippon Graphite Co., Ltd.]. “Everyome ME”] was applied and dried to form a cathode. Lead wires were pulled out from the silver paste, and terminals were connected.

(4) Measurement and evaluation <Evaluation of capacitance and internal resistance>
The solid electrolytic capacitor obtained above is connected to an LCR high tester [3532-50 manufactured by Hioki Electric Co., Ltd.], the capacitance is measured at a constant voltage level of 0.4 V and a frequency of 120 Hz, and the internal resistance is measured at a frequency of 100 kHz. It was measured. The results are shown in Tables 1 and 2.

<Evaluation of withstand voltage>
A voltage is applied to the solid electrolytic capacitor obtained above in a constant current mode of 0.2 mA with a DC power supply [PMC18-1A manufactured by Kikusui Electronics Co., Ltd.], the voltage is automatically boosted, and immediately before the voltage suddenly drops due to discharge. The voltage was regarded as a withstand voltage.

The solid electrolytic capacitors (Examples 1 to 13) using the solid electrolyte composition and the precursor composition for the solid electrolyte of the present invention maintained the low internal resistance necessary for the capacitor, while maintaining the theoretical capacitance (4.2 μF). ) Shown near value and high withstand voltage.
From the results of Tables 1 and 2, the solid electrolytic capacitors (Examples 1 to 13) using the solid electrolyte composition and the precursor composition for solid electrolyte of the present invention are equivalent to those of Comparative Examples 1 to 11. It has been found that it has a high capacitance and a high withstand voltage and has a low internal resistance.
Although this inventor was not expecting, since the adhesiveness of the electroconductive film containing a boric acid ester is favorable in Examples 1-13 compared with Comparative Examples 1-11, a solid electrolyte layer and a dielectric material As a result of the lowering of the interface resistance of the layer, it is assumed that it has a high withstand voltage and the internal resistance decreases.

  By using the solid electrolyte additive for solid electrolytic capacitors of the present invention, the increase in resistance of the solid electrolyte layer can be suppressed as much as possible, and the withstand voltage can be increased, and the solid electrolytic capacitor can be reduced in size, reduced in impedance, and highly reliable. The industrial value is great.

Claims (15)

Solid electrolyte additive (A) for solid electrolytic capacitors containing boric acid ester (H).   The boric acid ester (H) is obtained by reacting boric acid with a polyhydric alcohol (F1) having 2 to 10 carbon atoms and / or a monohydric alcohol (F2) having 1 to 10 carbon atoms. The additive according to claim 1.   The additive according to claim 1 or 2, wherein a boron content contained in the borate ester (H) is 7 to 16% by weight. Furthermore, the additive of any one of Claims 1-3 containing a solvent (C1).   The additive according to claim 4, wherein the solvent (C1) is a polyhydric alcohol (F1) having a boiling point of 300 ° C or lower.   The additive according to claim 4 or 5, wherein the content of borate ester (H) is 10 to 50% by weight based on the total weight of borate ester (H) and solvent (C1).   The solid electrolyte composition for solid electrolytic capacitors containing the additive (A) of any one of Claims 1-6, (pi) conjugated polymer compound (B), and a solvent (C2).   The composition according to claim 7, wherein the π-conjugated polymer compound (B) is at least one selected from the group consisting of a polypyrrole derivative and a polyaniline derivative.   The composition according to claim 7 or 8, wherein the content of the borate ester (H) is 5 to 300% by weight with respect to the weight of the π-conjugated polymer compound (B).   A precursor composition for a solid electrolyte for a solid electrolytic capacitor comprising the additive (A) according to any one of claims 1 to 6 and a precursor monomer (b) of a π-conjugated polymer compound.   The composition according to claim 10, wherein the precursor monomer (b) of the π-conjugated polymer compound is at least one selected from the group consisting of a pyrrole derivative and an aniline derivative.   The composition according to claim 10 or 11, wherein the content of the borate ester (H) is 5 to 300% by weight based on the weight of the precursor monomer (b) of the π-conjugated polymer compound.   Furthermore, the composition of any one of Claims 10-12 containing a solvent (C3).   The solid electrolyte precursor for a solid electrolytic capacitor according to any one of claims 7 to 9, wherein the solid electrolyte composition for a solid electrolytic capacitor according to any one of claims 7 to 9 is used. A conductive film for a solid electrolytic capacitor obtained by polymerizing the composition.   The solid electrolytic capacitor which has a conductive film for solid electrolytic capacitors of Claim 14.