JPH06204093A - Manufacture of solid electrolytic capacitor - Google Patents

Abstract

PURPOSE:To improve the characteristic of the product of a solid electrolytic capacitor and improve its manufacturing yield, by applying a hydration processing to the capacitor after its chemical polymerization, and thereafter, by applying an anodic oxidation to the capacitor, in the manufacturing method of the solid electrolytic capacitor wherein such a conductive polymer as polypyrrole is used as its solid electrolyte. CONSTITUTION:After the chemical polymerization of the manufacture of a solid electrolytic capacitor, a hydration processing is applied to the capacitor by the hot water of 50-95 deg.C in 5-30 minutes, and thereafter, an anodic oxidation is applied to the 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 polymer such as polypyrrole as a solid electrolyte.

[0002]

2. Description of the Related Art An electrolytic capacitor using a conductive polymer such as polypyrrole as a solid electrolyte has a dielectric film formed on a film-forming metal foil that has been roughened in advance, and a dielectric film is formed on the dielectric film. After forming a conductive polymer film by chemical polymerization of le, thiophenaniline or furan,
It has been studied to form a solid electrolyte by laminating a conductive polymer layer by electrolytic polymerization on the conductive polymer film in an aqueous solution containing the polymer monomer and the doping agent. In the above-mentioned chemical polymerization, the dielectric film is deteriorated together with the formation of the conductive polymer film. Therefore, the dielectric film is usually repaired by anodizing immediately after the chemical polymerization. .

[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. However, this method alone is not sufficient. If this is not done, problems such as variations in the leakage current characteristics of the product and an increase in leakage current will occur.

[0004]

DISCLOSURE OF THE INVENTION The present invention has solved the above-mentioned problems by forming a dielectric film on the surface of a foil made of a valve metal by anodic oxidation, and then forming a polymer film by chemical polymerization. A conductive polymer film such as thiophenaniline or furan is formed and then subjected to hydration treatment and anodic oxidation for 5 to 30 minutes in hot water at 50 to 95 ° C., followed by monomer and doping agent of the above polymer. A method for producing a solid electrolytic capacitor, which comprises forming an electrolytically polymerized polymer on the conductive polymer film in an aqueous solution containing

[0005]

The present invention exposes the defective portion of the dielectric film deteriorated by chemical polymerization by subjecting the conductive polymer film by chemical polymerization to hydration treatment with hot water at 50 to 90 ° C. for 5 to 30 minutes. In addition, it also forms a hydrated film, and the subsequent anodization has the effect of fully repairing the dielectric film.
The final product leakage current characteristics can be stabilized and reduced.

[0006]

[Example] Surface roughening in advance, and withstand voltage of 25 V
An aluminum foil having a corresponding dielectric film formed thereon was used as an anode, and the anode foil was chemically polymerized and immersed in an aqueous solution of ammonium persulfate of 0.05 mol / l, and then containing a pyrrole monomer of 3 mol / l. After dipping treatment in an acetonitrile solution to form a conductive polymer film, hot water treatment at 80 ° C. for 10 minutes and anodic oxidation were performed, and then electrolytic monomer polymerization was performed with a pyrrole monomer 0.02 mol / l. , As a supporting electrolyte.
Electrolytic polymerization was carried out in an aqueous solution containing 10 mol / l sodium naphthalene sulfonate at an electric quantity of 0.5 C / cm ² to form electropolymerized polypropylene by laminating. Then, a carbon layer was formed on this surface, a cathode lead of the counter electrode was attached using a silver paste, and the exterior was covered with an epoxy resin to manufacture a capacitor. Table 1 shows the characteristics of the leakage current of this capacitor one minute after the rated voltage was applied. Also,
The conventional products shown in Table 1 are those obtained by performing anodic oxidation immediately after chemical polymerization without performing hot water treatment after chemical polymerization.

[0007]

[Table 1]

【The invention's effect】

As shown in Table 1, after the chemical polymerization, 80
The leakage current characteristics of the product of the present invention, which has been subjected to warm water treatment at 10 ° C. for 10 minutes and anodization, are very low and stable. However, those of the conventional products that are not anodized during chemical polymerization are expensive and variable. When various studies were repeated as the influence of this hydration treatment, the treatment temperature was 50%.
If the treatment temperature is below 95 ° C or the treatment time is less than 5 minutes, no hydrated film is formed. Conversely, if the treatment temperature exceeds 95 ° C or the treatment time exceeds 30 minutes, the conductive polymer film is destroyed by chemical polymerization. It will be the same as the conventional product. Therefore, it was confirmed that the preferable treatment conditions for this 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 by using polypyrrole as a conductive polymer, but similar effects were confirmed with other polymers such as polythiophene, polyaniline and polyfuran.
As described above, the method for producing a solid electrolytic capacitor of the present invention greatly contributes to improvement of product characteristics and production yield, and has great industrial and practical value.

Claims (1)

[Claims] 1. A dielectric film is formed on a surface of a valve metal foil by anodic oxidation, and then a pyro-polymer is formed by chemical polymerization.
A conductive polymer film such as le, thiophenaniline or furan is formed, and then hydrated and anodized for 5 to 30 minutes in hot water at 50 to 95 ° C., and thereafter, a monomer and a monomer of the above polymer are added. A method for producing a solid electrolytic capacitor, which comprises forming an electrolytically polymerized polymer on the conductive polymer film in an aqueous solution containing a pinging agent.