JPH0714751A - Production of solid electrolytic capacitor - Google Patents

Abstract

PURPOSE:To enhance the production efficiency by forming a polyaniline film from a polyaniline solution having a specified structural unit as a principal repetitive unit and soluble to an organic solvent, treating the polyaniline film with a specified doping liquid to render the polyaniline film conductive, and employing the conductive polyaniline film as a solid electrolyte. CONSTITUTION:A dielectric oxide film is deposited on a film forming metal and a polyaniline solution, soluble to an organic solvent and having a quinone diimine structural unit and phenylenediamine structural unit shown by formula I (m and n represent mol.% of the quinone diimine structural unit and phenylenediamide structural unit in the repetitive unit and 0<m<1, 0<n<1, m+n=1) as a principal repetitive unit, is then applied to the dielectric film and dried to form a polyaniline film. Subsequently, the polyaniline film is rendered conductive using a dope liquid containing protic acid and an oxidizing agent and the conductive polyaniline film is employed as the solid electrolyte if an electrolytic capacitor.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a solid electrolytic capacitor using a conductive organic polymer as a solid electrolyte.

[0002]

2. Description of the Related Art An electrolytic capacitor is a capacitor in which an insulating coating is formed on a surface of a metal foil of aluminum or tantalum by electrolytic oxidation treatment and the insulating coating is used as a dielectric.
It has polarity so that the metal foil serves as an anode and the electrolyte side serves as a cathode. Recent major technical requirements for electrolytic capacitors include miniaturization, low impedance accompanying high-frequency circuits, high reliability, and low cost. In order to meet these requirements, research has been conducted in the direction of solidifying the electrolyte of a liquid electrolytic capacitor, and as such a solid electrolyte, for example, various conductive materials such as polypyrrole, polythiophene, polyfuran, and polyaniline can be used. Polymers have been proposed.

More specifically, for example, JP-A-63-17
No. 3313 discloses that a dielectric oxide film is formed on a film-forming metal, polypyrrole is deposited on the dielectric oxide film by chemical oxidative polymerization of pyrrole, and this is used as a conductive layer. , Pyrrole is electrolytically polymerized, and a conductive polymer composed of the polypyrrole is laminated as a solid electrolyte. In addition, JP-A-1-253
Similarly, Japanese Patent Laid-Open No. 226 describes that a conductive layer made of manganese dioxide is formed on a dielectric film, and polypyrrole or polythiophene is laminated thereon by electrolytic polymerization to form a solid electrolyte.

However, in all of these methods, it is necessary to laminate polypyrrole or the like on the dielectric film that is not a conductor by an electrolytic reaction, which is problematic. That is, a chemical oxidation polymerization film layer or a manganese dioxide layer must be provided on the dielectric film as a conductive layer to serve as an electrode for electrolytic polymerization, and electrolytic polymerization can be performed only in this way.

On the other hand, in Japanese Patent Laid-Open No. 3-35516,
A method has been proposed in which polyaniline in a solution state is applied onto a dielectric film to form a film, and then the polyaniline film is dipped in a solution of a protonic acid to perform a doping treatment. According to this method, a conductive polyaniline film can be formed on the dielectric film by a simple means without providing an electrode, which is advantageous in terms of manufacturing efficiency and cost.

[0006]

However, in the doping treatment of the polyaniline film in the protic acid solution,
Requires hours to days. As described above, it is not preferable that the doping process takes a long time from the viewpoint of manufacturing efficiency, and the protonic acid may penetrate from the polyaniline film and corrode the film forming metal that is the anode of the solid electrolytic capacitor. There is also.

The present invention has been made in order to solve the above-mentioned problems in the production of a solid electrolytic capacitor using a conventional conductive polyaniline film as a solid electrolyte. It is possible to form a solid electrolytic capacitor using a conductive polyaniline film as a solid electrolyte by solving the disadvantage of the manufacturing process, which requires a long time for the doping process described above, by forming the solid electrolytic capacitor on the dielectric film by various methods. The object is to provide a process which can be manufactured well.

[0008]

A method for manufacturing a solid electrolytic capacitor according to the present invention comprises forming a dielectric oxide film on a film-forming metal, and forming a dielectric oxide film on the dielectric oxide film using a general formula.

[0009]

[Chemical 2]

(In the formula, m and n respectively represent the mole fractions of the quinonediimine structural unit and the phenylenediamine structural unit in the repeating unit, and 0 <m <1, 0 <n <1, m +
n = 1. ) Has a quinonediimine structural unit and a phenylenediamine structural unit as main repeating units, and a solution of polyaniline soluble in an organic solvent is applied and dried to form a polyaniline film. The polyaniline film is treated with a dope solution containing an acid and an oxidizing agent to make the polyaniline film conductive, and the polyaniline film is used as a solid electrolyte.

In the present invention, as the film-forming metal,
Generally, aluminum or tantalum is used,
If necessary, other metal or alloy composites can be used. A dielectric film is formed on such a film-forming metal to form an anode body of an electrolytic capacitor. The polyaniline used in the present invention is a solvent-soluble polyaniline in the undoped state, and is represented by the general formula (I). The production of such polyaniline, the dedoping method, the solubility in a solvent and the like are described in detail in JP-A-3-28229. In particular,
The polyaniline used in the present invention has an intrinsic viscosity [η] of 0.40 measured at 30 ° C. in N-methylpyrrolidone.
It is preferably dl / g or more. Thus, the polyaniline used in the present invention is distinguished from the conventionally known polyaniline in that it has a higher molecular weight and is soluble in a solvent, as described in detail in JP-A-3-28229. , And can also be structurally distinguished.

A polymer having a quinonediimine structural unit represented by the general formula (I) and a phenylenediamine structural unit as main repeating units used in the present invention, which is a polyaniline soluble in an organic solvent in a dedoped state (hereinafter referred to as "polyaniline"). As described in detail in JP-A-3-28229, the acid-dissociation constant pKa value is 3.0 or less in the presence of a protic acid in a solvent. While maintaining the temperature of aniline at 5 ° C. or lower, preferably 0 ° C. or lower, an oxidizing agent whose standard electrode potential determined as an electromotive force in a reducing half-cell reaction with a standard hydrogen electrode as a reference is 0.6 V or more An equivalent amount, defined as the amount of an aqueous solution, per mole of aniline, of 1 mole of oxidant divided by the number of electrons required to reduce one molecule of oxidant, An equivalent amount or more, preferably 2 to 2.5 equivalents, is gradually added to produce an oxidized polymer of aniline doped with the above-mentioned protonic acid (hereinafter referred to as doped polyaniline), and this doped polyaniline is then added. Can be obtained by dedoping with a basic substance.

Thus, the polyaniline obtained by oxidatively polymerizing aniline in the presence of a protonic acid to obtain polyaniline, and then dedoping this polyaniline has a high molecular weight and is suitable for various organic solvents. Dissolve. As such an organic solvent, N-methyl-2-pyrrolidone,
N, N-dimethylacetamide, N, N-dimethylformamide, dimethyl sulfoxide, 1,3-dimethyl-2-imidazolidinone, sulfolane and the like can be mentioned.
The solubility depends on the average molecular weight of the dedoped polyaniline and the solvent, but 0.5 to 100% of the polymer dissolves and
A ~ 30 wt% solution can be obtained. In particular, dedoped polyaniline shows a high solubility in N-methyl-2-pyrrolidone, and usually 20 to 100% of the polymer is dissolved and a 3 to 30% by weight solution can be obtained. However, it does not dissolve in tetrahydrofuran, 80% acetic acid aqueous solution, 60% formic acid aqueous solution, acetonitrile or the like.

Further, according to the present invention, the undoped polyaniline can be partially or completely reduced with a reducing agent before use. The degree of reduction of the polyaniline can be adjusted by selecting the equivalent ratio of the reducing agent used to polyaniline. The degree of reduction of the polyaniline is such that the polyaniline is N-methyl-
It can be evaluated from the electronic spectrum of the solution dissolved in 2-pyrrolidone. Solvent-soluble polyaniline N
-Methyl-2-pyrrolidone solution has an electronic spectrum of 3
It has a maximum absorption at 40 nm and 640 nm. When the polyaniline represented by the general formula (I) is completely reduced, the absorption at 640 nm disappears and the intensity of the absorption at 340 nm increases, so that the absorption at 640 nm originates from the quinonediimine structure and the absorption at 340 nm is phenylenediamine. It is considered to be derived from the structure.

For such reduction of polyaniline, hydrazines such as hydrazine hydrate and phenylhydrazine, metal hydrides such as lithium aluminum hydride and lithium borohydride, and hydrogen are preferably used. Although it is soluble in an organic solvent, particularly N-methyl-2-pyrrolidone, it does not reduce N-methyl-2-pyrrolidone,
Phenylhydrazine is most preferably used.

In the present invention, as the solvent-soluble polyaniline, in the polyaniline represented by the general formula (I), the mole fraction n of the phenylenediamine structural unit is n.
Is preferably used in which the polyaniline is larger than the molar fraction m of the quinonediimine structural unit. Therefore, as described above, a partially or completely reduced polyaniline is preferably used.

According to the method of the present invention, first, a dielectric film is formed on a film-forming metal, then a film made of polyaniline as described above is formed on the dielectric film, and this polyaniline film is formed. A solid electrolytic capacitor can be obtained by conducting a doping treatment to make it conductive and making it a solid electrolyte. To form a polyaniline film, specifically, a solution of the polyaniline represented by the general formula (I) is applied onto the dielectric coating, or the dielectric coating is subjected to atmospheric pressure or vacuum to obtain the polyaniline solution. Then, the solvent may be dried under normal pressure or under vacuum. The polyaniline film thus obtained is still in a dedoped state and has no conductivity.

In the present invention, the dope solution used for doping the polyaniline film formed as described above is a mixed solution containing a protonic acid and an oxidizing agent. The protonic acid that can be used in the present invention is not particularly limited as long as it can dope such a polyaniline film, but in particular, the acid dissociation constant pKa value is
4.8 or less is preferable, and further, organic polyvalent sulfonic acid is preferable in order to impart various required durability such as heat resistance, water resistance, and moist heat resistance to the obtained solid electrolytic capacitor. The organic polyvalent sulfonic acid may be an aromatic polyvalent sulfonic acid or an aliphatic polyvalent sulfonic acid.

Examples of aromatic polyvalent sulfonic acids that can be preferably used in the present invention include benzenedisulfonic acid, naphthalene disulfonic acid, naphthalene trisulfonic acid, naphthalene tetrasulfonic acid, anthracene disulfonic acid, anthraquinone disulfonic acid, and phenanthrene. Disulfonic acid, fluorenone disulfonic acid, carbazole disulfonic acid, diphenylmethane disulfonic acid, biphenyl disulfonic acid, terphenyl disulfonic acid, terphenyl trisulfonic acid, naphthalene sulfonic acid-formalin condensate, phenanthrene sulfonic acid-formalin condensate, anthracene Examples thereof include a sulfonic acid-formalin condensate, a fluorene sulfonic acid-formalin condensate, and a carbazole sulfonic acid-formalin condensate. The position of the sulfonic acid group in the aromatic ring is arbitrary. Further, the aromatic ring has an alkyl group, an alkoxy group,
It may contain a substituent such as a hydroxyl group, a nitro group, a cyano group or an amino group.

Examples of the aliphatic polyvalent sulfonic acid which can be preferably used in the present invention include methanedisulfonic acid, 1,1-ethanedisulfonic acid, 1,2-ethanedisulfonic acid and 1,1-propane. Disulfonic acid, 1,3-
Examples thereof include propanedisulfonic acid and 2,2-propanedisulfonic acid. Further, the organic polyvalent sulfonic acid used in the present invention may be a polymer acid. Examples of such a polymer acid include polyvinyl sulfonic acid, polyvinyl sulfuric acid, polystyrene sulfonic acid, sulfonated styrene-butadiene copolymer, polyallyl sulfonic acid, polymethallyl sulfonic acid, poly-2-acrylamido-2-methyl. Examples thereof include propane sulfonic acid, polyisoprene sulfonic acid, sulfopropyl polyacrylate, and polysulfomethyl styrene.

As the oxidizing agent, those which do not generate anions in the solution per se or the reductant after the oxidation reaction are preferably used. Examples of such an oxidizing agent include peroxides such as hydrogen peroxide and hydroperoxide, peracids such as m-chloroperbenzoic acid, p-benzoquinone, o-benzoquinone, p-toluquinone and oxy-p-benzoquinone. , 1, 2
-Naphthoquinone, 1,4-naphthoquinone, diphenoquinone, stilbenquinone, chloranil, 2,3-dichloro-
Quinones such as 5,6-dicyano-p-benzoquinone, sodium 1,2-naphthoquinone-4-sulfonate, sodium 1,4-naphthoquinone-2-sulfonate, and tetrafluoro-p-benzoquinone and their derivatives are listed. be able to.

According to the present invention, the above-mentioned oxidizing agent and protonic acid are dissolved in a suitable solvent such as water, an organic solvent, or a mixture of water and an organic solvent to prepare a dope solution. The polyaniline film is doped by bringing the polyaniline film formed on the dielectric film as described above into contact with this dope solution. Although the concentration of the dope solution depends on the temperature of the doping process and the thickness of the formed polyaniline film, the protonic acid is usually 1 to
The range of 40 wt% and the oxidizing agent is preferably 1 to 30 wt%. More specifically, for example, when 1,2-ethanedisulfonic acid is used as the protonic acid and hydrogen peroxide is used as the oxidant, 1,2-ethanedisulfonic acid is contained in an amount of 5 to 30% by weight, and Hydrogen oxide is preferably in the range of 3 to 30% by weight. Further, when 1,5-naphthalenedisulfonic acid is used as the protonic acid and p-benzoquinone is used as the oxidant, 1,5-naphthalenedisulfonic acid is 5-2
The range of 0% by weight and p-benzoquinone is preferably in the range of 1 to 8% by weight.

The temperature of the doping process is usually 1
It is in the range of 0 to 60 ° C. If the doping process is performed at a higher temperature, the required time can be shortened, but if the temperature is too high, the mechanical strength of the polyaniline film is deteriorated. In the present invention, after the polyaniline film is formed on the dielectric film, the polyaniline film is treated with the above-described dope solution to perform the doping treatment. More specifically, a method such as immersing the polyaniline film in the dope solution, coating the polyaniline film with the dope solution, or spraying the dope solution may be used.

According to the present invention, the doping rate of the polyaniline film is dramatically improved by using the mixed solution containing the protonic acid and the oxidizing agent as the dope solution. This is because when an electron is taken from the unshared electron pair of the imino nitrogen of the reduced polyaniline moiety by the oxidizing agent, a cation radical called a semiquinone radical is generated, a charge site is generated, and an electrostatic field is formed, It is considered that this is because the anion of the dopant is easily incorporated into the polyaniline by the electrostatic force. On the other hand, in the protonic acid doping into the quinonediimine structure portion, such electrostatic interaction does not work, and it depends on only the diffusion of the protonic acid, so that the protonic acid doping is considered to be slow.

After such a doping process, the polyaniline film is washed with an appropriate solvent such as ethanol and dried, and then terminals are attached on the polyaniline film by using a conductive paste such as carbon or silver. Then, mold with epoxy resin etc. and perform aging treatment,
Obtain a solid electrolytic capacitor. In the present invention, usually aluminum or tantalum is preferably used as the film-forming metal, and accordingly, as the dielectric film, usually an aluminum oxide or tantalum oxide film is preferably used.

[0026]

As described above, according to the method of the present invention,
The polyaniline film formed on the dielectric film can be doped in a short time, and thus a solid electrolytic capacitor using the conductive polyaniline film as a solid electrolyte can be easily and efficiently obtained.

[0027]

The present invention will be described below with reference to reference examples and examples, but the present invention is not limited to these. Reference Example 1 (Production of quinonediimine / phenylenediamine type conductive polyaniline in a doped state by oxidative polymerization of aniline)
In a 10-liter separable flask equipped with a stirrer, a thermometer and a straight pipe adapter, 6000 g of distilled water, 3
360 ml of 6% hydrochloric acid and 400 g (4.295 mol) of aniline were charged in this order to dissolve the aniline. Separately, while cooling with ice water, distilled water 149 in a beaker
Add 434 g (4.295 mol) of 97% concentrated sulfuric acid to 3 g,
A sulfuric acid aqueous solution was prepared by mixing. This sulfuric acid aqueous solution was added to the separable flask, and the entire flask was cooled to -4 ° C in a low temperature constant temperature bath.

Next, 980 g (4.295 mol) of ammonium peroxodisulfate was added to 2293 g of distilled water in a beaker and dissolved to prepare an oxidizing agent aqueous solution. The entire flask was cooled in a low temperature constant temperature bath, while maintaining the temperature of the reaction mixture at -3 ° C or lower, while stirring, to an acidic aqueous solution of aniline salt, using a tubing pump, using a straight pipe adapter, the above ammonium peroxodisulfate aqueous solution. 1 ml
The mixture was gradually added dropwise at a rate of not more than / minute. Initially, the colorless and transparent solution changes from green-blue to black-green as the polymerization proceeds,
Then, a black-green powder was deposited.

Although a temperature rise was observed in the reaction mixture during the powder deposition, the temperature in the reaction system was cooled to -3.
The temperature was kept below ℃. After the powder is deposited, the dropping rate of the aqueous ammonium peroxodisulfate solution may be slightly increased, for example, about 8 ml / min. However, also in this case, it is necessary to monitor the temperature of the reaction mixture and adjust the dropping rate so as to maintain the temperature at −3 ° C. or lower. Thus, after the dropping of the aqueous ammonium peroxodisulfate solution was completed over 7 hours, the stirring was continued for another 1 hour at a temperature of -3 ° C or lower.

The obtained polymer powder was filtered, washed with water, washed with acetone, and dried in vacuum at room temperature to obtain a black-green quinonediimine / phenylenediamine type conductive polyaniline powder 4
30 g was obtained. This was pressure-molded into a disk having a diameter of 13 mm and a thickness of 700 μm, and by the van der Pauw method,
The conductivity was measured and found to be 14 S / cm. (Production of Quinonediimine / Phenylenediamine Type Solvent-Soluble Polyaniline by Dedoping of Conductive Organic Polymer) The doped conductive polyaniline powder 35
0 g was added to 4 liters of 2N ammonia water, and the mixture was stirred with an auto homomixer at a rotation speed of 5000 rpm for 5 hours. The mixture changed from black green to blue purple.

The powder was filtered off with a Buchner funnel, washed repeatedly with distilled water while stirring in a beaker until the filtrate became neutral, and then washed with acetone until the filtrate became colorless. did. Then, the powder was vacuum dried at room temperature for 10 hours to obtain 280 g of a dark brown dedoped solvent-soluble quinonediimine / phenylenediamine type polyaniline powder. This polyaniline is N-methyl-2-
Soluble in pyrrolidone, the solubility is 100g of the same solvent
To 8 g (7.4%). The intrinsic viscosity [η] measured at 30 ° C. using this as a solvent was 1.23.

Example 1 Etched aluminum (thickness: 70 μm, area: 1 cm ² ) was used as a film-forming metal, and the temperature was about 70 ° C.
DC voltage of 50 V is applied in the 3 wt% ammonium adipate aqueous solution to form an insulating film (dielectric film),
It was used as the anode body of the capacitor. 5 g of the above-mentioned soluble polyaniline was dissolved in 95 g of N-methyl-2-pyrrolidone with stirring to give a 5% by weight polyaniline solution. Furthermore,
To this was gradually added 0.75 g of phenylhydrazine. At this time, the solution changed its color from dark blue to blackish brown, and at the same time, generation of nitrogen gas was confirmed. This solution was filtered under reduced pressure with a G2 glass filter.

After immersing the capacitor anode body in the polyaniline solution at room temperature for 1 minute, a hot air circulating dryer (15
It was heated and dried in 0 ° C.) for 30 minutes to form a polyaniline film on the anode body. This operation was repeated 3 times in total. The capacitor anode body laminated with the polyaniline film thus obtained was immersed in an aqueous solution at 40 ° C. containing 15% by weight of 1,2-ethanedisulfonic acid and 3.8% by weight of hydrogen peroxide.
After soaking for 0 minute and doping treatment, it was washed with ethanol and dried at 60 ° C. for 20 minutes. Then, a conductive paste was applied and electrode terminals were attached.

The solid electrolytic capacitor thus obtained had a capacitance of 5.75 μF at 120 Hz and a tangent of loss angle (tan δ) of 5.5%. Also,
Equivalent series resistance (ESR) at 1MHz is 165mΩ
It was.

Example 2 The same 5% by weight polyaniline solution as in Example 1 was applied onto the same anode body as in Example 1 and deaerated in a vacuum drier,
It was heated in the same vacuum drier and kept at 130 ° C. for 20 minutes to be dried to form a polyaniline film on the anode body.
15% by weight of 1,2-ethanedisulfonic acid was added to the capacitor anode body on which the polyaniline film thus obtained was formed.
It was dipped in an ethanol / water mixed solution containing 40% by weight and p-benzoquinone of 2.0% by weight at 40 ° C. for 30 minutes for doping treatment, washed with ethanol, and dried at 60 ° C. for 20 minutes. Then, a conductive paste was applied and electrode terminals were attached.

The solid electrolytic capacitor thus obtained had a capacitance of 6.39 μF at 120 Hz and a loss angle tangent (tan δ) of 4.2%. Also,
Equivalent series resistance (ESR) at 1MHz is 130mΩ
It was.

Example 3 The same 5% by weight polyaniline solution as in Example 1 was applied onto the same anode body as in Example 1 and deaerated in a vacuum drier,
It was heated in the same vacuum drier and kept at 130 ° C. for 20 minutes to be dried to form a polyaniline film on the anode body.
15% by weight of 1,2-ethanedisulfonic acid was added to the capacitor anode body on which the polyaniline film thus obtained was formed.
And sodium 1,2-naphthoquinone-4-sulfonate 2.5
The mixture was dipped in a N-methylformamide / water mixed solution containing 40 wt% for 60 minutes at 40 ° C., subjected to doping treatment, washed with ethanol, and dried at 60 ° C. for 20 minutes. Then, terminals were attached in the same manner as in Example 1.

The solid electrolytic capacitor thus obtained had a capacitance of 6.12 μF at 120 Hz and a loss angle tangent (tan δ) of 3.4%. Also,
Equivalent series resistance (ESR) at 1MHz is 168mΩ
It was.

Example 4 The same 5% by weight polyaniline solution as in Example 1 was applied onto the same anode body as in Example 1 and deaerated in a vacuum drier,
It was heated in the same vacuum drier and kept at 130 ° C. for 20 minutes to be dried to form a polyaniline film on the anode body.
The polyaniline film-formed capacitor anode body thus obtained was mixed with 10% by weight of polyvinyl sulfonic acid and p.
It was immersed in an ethanol / water mixed solution containing 2.5% by weight of benzoquinone at 40 ° C. for 60 minutes, doped, washed with ethanol, and dried at 60 ° C. for 20 minutes. Then, terminals were attached in the same manner as in Example 1.

The solid electrolytic capacitor thus obtained had a capacitance of 6.06 μF at 120 Hz and a loss angle tangent (tan δ) of 6.3%. Also,
Equivalent series resistance (ESR) at 1MHz is 147mΩ
It was.

Example 5 As a film forming metal, a porous sintered body (area: 20.8 mm ² ) obtained by sintering fine powder of tantalum was used, and a DC voltage of 100 V was applied in a 0.3 wt% phosphoric acid aqueous solution at 90 ° C. Was applied to form an insulating film (dielectric film), which was used as the anode body of the capacitor. The above-mentioned soluble polyaniline was dissolved in N-methyl-2-pyrrolidone with stirring to give a 10% by weight polyaniline solution. After immersing the capacitor anode body in the polyaniline solution for 1 minute, a hot air circulating dryer (150
(30 ° C.) and dried for 30 minutes to form a polyaniline film on the anode body. This operation was repeated 3 times in total.

The polyaniline film-formed capacitor anode body thus obtained contained 40% by weight of 1,2-ethanedisulfonic acid (15% by weight) and p-benzoquinone (2.0% by weight).
Immerse in ethanol / water mixed solution at ℃ for 30 minutes, dope, wash with ethanol, and then at 20 ℃ at 20 ℃.
Allow to dry for minutes. Then, a conductive paste was applied and electrode terminals were attached. The solid electrolytic capacitor thus obtained had a capacitance of 23.8 μF at 120 Hz and a tangent of loss angle (tan δ) of 1.5%.
The equivalent series resistance (ESR) at 1 MHz is 32.
It was 8 mΩ.

Comparative Example 2 After the same anode body as in Example 5 was impregnated with an aqueous solution of manganese nitrate, a pyrolysis treatment was carried out to form a manganese dioxide layer as a solid electrolyte. Furthermore, after re-forming, electrode terminals were attached with a conductive paste. The solid electrolytic capacitor thus obtained has a capacitance of 21.4 μF at 120 Hz and a tangent (tan
δ) was 5.1%. The equivalent series resistance (ESR) at 1 MHz was 984 mΩ.

─────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] December 8, 1992

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0041

[Correction method] Change

[Correction content]

Example 5 As a film-forming metal, a porous sintered body ( volume 20.8 mm ³ ) obtained by sintering fine powder of tantalum was used, and a DC voltage was applied in a 0.3 wt% phosphoric acid aqueous solution at 90 ° C. 100 V was applied to form an insulating coating (dielectric coating), which was used as the anode body of the capacitor. The above-mentioned soluble polyaniline was dissolved in N-methyl-2-pyrrolidone with stirring to give a 10% by weight polyaniline solution. After immersing the capacitor anode body in the polyaniline solution for 1 minute, a hot air circulating dryer (150
(30 ° C.) and dried for 30 minutes to form a polyaniline film on the anode body. It was repeated three times in total this operation.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0043

[Correction method] Change

[Correction content]

Comparative Example 1 The same anode body as in Example 1 was used with aluminum as a cathode body.
And place separator paper between it and the anode body.
Ammonium adipate water / ethylene glycol mixture
The separator paper was dipped in the combined solution to impregnate the solution with the solution. Anode and
Terminals were drawn out from both aluminum of the cathode and cathode. This
Wet electrolytic capacitor obtained in this way
Has a capacitance of 6.44 μF and the tangent of the loss angle
(Tan δ) was 8.0%. Also, at 1 MHz
The equivalent series resistance (ESR) was 1220 mΩ. Comparative Example 2 After the same anode body as in Example 5 was impregnated with an aqueous solution of manganese nitrate, a manganese dioxide layer was formed as a solid electrolyte by thermal decomposition treatment. Furthermore, after re-forming, electrode terminals were attached with a conductive paste. The solid electrolytic capacitor thus obtained has a capacitance of 21.4 μF at 120 Hz and a tangent of loss angle (tan
δ) was 5.1%. The equivalent series resistance (ESR) at 1 MHz was 984 mΩ.

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Akira Otani 1-2-1 Shimohozumi, Ibaraki City, Osaka Prefecture Nitto Denko Corporation

Claims (5)

[Claims] Claim: What is claimed is: 1. A dielectric oxide film is formed on a film-forming metal, and a general formula: (In the formula, m and n each represent a mole fraction of the quinonediimine structural unit and the phenylenediamine structural unit in the repeating unit, and 0 <m <1, 0 <n <1, and m + n = 1). Having a quinonediimine structural unit and a phenylenediamine structural unit as main repeating units,
Apply a solution of polyaniline that is soluble in organic solvents,
It is dried to form a polyaniline film, and then the polyaniline film is treated with a dope solution containing a protonic acid and an oxidizing agent to make the polyaniline film conductive, and this is used as a solid electrolyte. Method for manufacturing solid electrolytic capacitor. 2. A polyaniline soluble in an organic solvent is N
The method for producing a solid electrolytic capacitor according to claim 1, wherein the intrinsic viscosity [η] measured in methyl-2-pyrrolidone at 30 ° C. is 0.40 dl / g or more. 3. The method for producing a solid electrolytic capacitor according to claim 1, wherein the protonic acid is an organic polyvalent sulfonic acid. 4. The method for producing a solid electrolytic capacitor according to claim 1, wherein the oxidizing agent itself and the reductant after the oxidation reaction do not generate anions in the solution. 5. The method for producing a solid electrolytic capacitor according to claim 4, wherein the oxidant is a peroxide oxidant or a quinone oxidant.