Electroconductive polymer composition, method for producing the same, and solid electrolytic capacitor using electroconductive polymer composition

A method for producing an electroconductive polymer composition, comprising:

• a first step of synthesizing a polyanion having a cross-linked structure by a reaction of a cross-linking agent with a polyanion in an aqueous solvent;
• a second step of obtaining a mixture containing an electroconductive polymer by chemical oxidative polymerization of a monomer giving the electroconductive polymer by using an oxidant in a solvent containing a dopant consisting of an organic acid or a salt thereof,
• a third step of collecting the electroconductive polymer from the mixture,
• a fourth step of forming an electroconductive polymer suspension solution by mixing the polyanion having a cross-linked structure and the electroconductive polymer with an oxidant in the aqueous solvent, and
• a fifth step of drying the electroconductive polymer suspension solution,
• wherein the polyanion having a cross-linked structure has a main chain of a polystyrene sulfonic acid,
• wherein the polyanion having a cross-linked structure has a structure obtained by cross-linking a straight-chain polystyrene sulfonic acid using a cross-linking agent, and
• wherein the cross-linking agent is a compound having two or more epoxy groups selected from the group consisting of sorbitol potyglyeidyl ethers, polyglycerol polyglycidyl ethers, pentaerythritol polyglycidyl ethers, diglycerol polyglycidyl ethers, glycerol polyglycidyl ethers,trimethylolpropane polyglycidyl ethers, resorcinol diglycidyl ether, neopentyl glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, polyethylene glycol diglycidyl ethers, polypropylene glycol diglycidyl ethers, polybutadiene diqlycidyl ethers, diglycidyl o-phthalate, hydroquinone diglycidyl ethers, digivcidyl terephthalate, dibromo neopentyl glycol diglycidyl ether, and bisphenol A type epoxy resins.