Method of manufacturing conductive polymer microparticle dispersion and method of manufacturing electrolytic capacitor containing the conductive polymer microparticle dispersion

1. A method of manufacturing a conductive polymer microparticle dispersion, the method comprising:

preparing a polyanion which is at least one of polystyrene sulfonic acids and polystyrene sulfonates each having a Hazen color number in a range of 10 to 1000, inclusive, when a hue of a 2% aqueous solution thereof is measured by American Public Health Association method;

preparing a dispersion liquid by dispersing, in a solvent mainly composed of water, at least one monomer selected from thiophenes and derivatives thereof, and the polyanion as a dopant; and

preparing a conductive polythiophene microparticle dispersion doped with the polyanion by mixing the dispersion liquid with an oxidizing agent so as to oxidatively polymerize the at least one monomer.

2. A method of manufacturing an electrolytic capacitor, the method comprising:

impregnating a capacitor element having a positive electrode formed with a dielectric layer thereon with the conductive polymer microparticle dispersion prepared by the method of claim 1 ; and

forming a conductive polymer solid electrolyte layer between the positive electrode and a negative electrode by removing a solvent component contained in the conductive polymer microparticle dispersion.

3. The method of manufacturing a conductive polymer microparticle dispersion according to claim 1 , wherein a content of the polyanion with respect to 1 weight parts of the monomer falls within a range from 1 to 5 weight parts, inclusive, when preparing the dispersion liquid.