JP3359364B2 - Method for manufacturing solid electrolytic capacitor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[0002]

2. Description of the Related Art In an electrolytic capacitor using a conductive polymer such as polypyrrole as a solid electrolyte, a dielectric film is formed on a film-forming metal foil that has been roughened in advance, and pyrrole, thiophene, and thiophene are formed on the dielectric film. After forming the conductive polymer film by chemical polymerization of aniline or furan, the conductive polymer layer is formed by electrolytic polymerization on the conductive polymer film in an aqueous solution containing a monomer of the above polymer and a doping agent. What constitutes a laminated solid electrolyte is being studied. And since the above-mentioned chemical polymerization causes the deterioration of the dielectric film along with the formation of the conductive polymer film,
Immediately after chemical polymerization, anodization is usually performed to repair the dielectric film.

[0003]

However, in the above-described method for manufacturing a solid electrolytic capacitor, the dielectric film deteriorated by chemical polymerization is repaired by subsequent anodic oxidation. Otherwise, problems such as variations and increased leakage current occur in the leakage current characteristics of the product.

[0004]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and comprises forming a dielectric film by anodic oxidation on the surface of a foil made of valve metal, and then forming a pyrrole, thiophene, or thiophene by chemical polymerization. Forming a conductive polymer film made of at least one of aniline and furan;
After the hydration treatment of immersion in hot water at 95 ° C. for 5 to 30 minutes, anodization is performed, and then an electropolymerized polymer is formed on the conductive polymer film in an aqueous solution containing the polymer monomer and a doping agent. A method for manufacturing a solid electrolytic capacitor, characterized in that:

[0005]

According to the present invention, the conductive polymer film formed by chemical polymerization is subjected to a hydration treatment with warm water at 50 to 90 ° C. for 5 to 30 minutes to expose a defective portion of the dielectric film deteriorated by chemical polymerization. In addition, the formation of a hydrated film is performed, and the subsequent anodization has the effect of sufficiently restoring the dielectric film.
It is possible to stabilize and reduce the leakage current characteristics of the final product.

[0006]

EXAMPLE The surface was roughened beforehand and a withstand voltage of 25 V
An aluminum foil on which a considerable dielectric film is formed is used as an anode, and after immersion treatment in an aqueous solution of 0.05 mol / l ammonium persulfate as a chemical polymerization on the anode foil, contains 3 mol / l of a pyrrole monomer. After immersion in an acetonitrile solution to form a conductive polymer film, hot water treatment at 80 ° C. for 10 minutes and anodic oxidation are performed, and then 0.02 mol / l of a pyrrole monomer is subjected to electrolytic polymerization. , As supporting electrolyte.
In an aqueous solution containing 10 mol / l sodium naphthalenesulfonate, electrolytic polymerization was performed at an electric quantity of 0.5 C / cm ² to form an electrolytically polymerized polypyrrol. Then, a carbon layer was formed on the surface, a cathode lead of a counter electrode was attached using silver paste, and the package was formed using an epoxy resin to make a capacitor. Table 1 shows the leakage current characteristics of this capacitor one minute after the application of the rated voltage. Also,
The conventional products shown in Table 1 are those subjected to anodic oxidation immediately after chemical polymerization without performing warm water treatment after chemical polymerization.

[0007]

[Table 1]

【The invention's effect】

As shown in Table 1, after chemical polymerization,
After subjecting to warm water treatment at 10 ° C. for 10 minutes and anodic oxidation, the leakage current characteristics of the product of the present invention are very low and stable. However, those of conventional products that have not been anodized during chemical polymerization are high and variable. After various studies as to the effect of this hydration treatment, the treatment temperature was 50
If the processing temperature is lower than 95 ° C or the processing time exceeds 30 minutes, the conductive polymer film may be destroyed by the chemical polymerization if the processing temperature exceeds 95 ° C or the processing time exceeds 30 minutes. It will not be different from conventional products. Therefore, it was confirmed that the desirable conditions for the hydration treatment were a treatment temperature of 50 to 95 ° C. and a treatment time of 5 to 30 minutes. As an example, the effect of the present invention was compared with polypyrrol as the conductive polymer. Similar effects were confirmed with other polymers such as polythiophene, polyaniline and polyfuran.
As described above, the method for manufacturing a solid electrolytic capacitor of the present invention greatly contributes to improvement of product characteristics and manufacturing yield, and has great industrial and practical value.

Claims (1)

(57) [Claims] 1. A dielectric polymer film is formed by anodic oxidation on a surface of a valve metal foil, and then a conductive polymer film made of at least one of pyrrole, thiophene, aniline or furan is formed by chemical polymerization. And then 50-9
After hydration treatment of immersion in 5 ° C. warm water for 5 to 30 minutes, anodization is performed, and then an electropolymerized polymer is formed on the conductive polymer film in an aqueous solution containing the polymer monomer and a doping agent. A method for manufacturing a solid electrolytic capacitor, comprising: