Electroconductive Polymer Composition for Solid Electrolytic Capacitors

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Solution Overview

Problem

Existing electroconductive polymer compositions have insufficient film forming properties and electroconductivity, which limits their application in high-capacity solid electrolytic capacitors with low Equivalent Series Resistance (ESR).

Innovation Solution

An electroconductive polymer composition is developed through oxidation polymerization using a reaction solution containing pyrrole, thiophene, or their derivatives, a polyacid or its salt as a dopant, and a solvent mixture of water and an aprotic solvent, which enhances film forming properties and electroconductivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If oxidation polymerization is performed in aqueous solvent using conventional methods, then electroconductive polymer can be obtained, but film forming property is insufficient

Engineering Contradiction:

Improvefilm forming propertyVSAvoidproduction method complexity

Core Design Contradiction:

Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The patent changes the solvent system from pure aqueous solvent to a mixed solvent system comprising water and organic solvent (acetonitrile, dimethylformamide, dimethylacetamide, or N-methyl-2-pyrrolidone). This parameter change in the reaction medium enables the electroconductive polymer to form films with excellent adhesion and uniformity, directly resolving the film forming property issue while maintaining the oxidation polymerization process.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite solvent system combining water and specific organic solvents. This composite approach leverages the beneficial properties of both solvent types: water provides polarity and solubility for the polymer, while the organic solvent component enhances film formation characteristics and adhesion, resulting in superior film forming properties without complicating the manufacturing process.

Inventive Principle:

Principle #40Composite materials

2Reliability

If oxidation polymerization is performed in aqueous solvent using conventional methods, then electroconductive polymer can be obtained, but electroconductivity is insufficient

Engineering Contradiction:

ImproveelectroconductivityVSAvoidproduction method complexity

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent modifies the reaction conditions by changing the solvent composition to include water and organic solvent in specific ratios. This parameter change affects the polymerization process, leading to electroconductive polymers with enhanced conductivity. The organic solvent component facilitates better polymer chain arrangement and dopant distribution, directly improving electroconductivity while keeping the oxidation polymerization method straightforward.

Inventive Principle:

Principle #35Parameter changes

3Manufacturing precision

If solvent is removed from electroconductive polymer composition, then electroconductive polymer material is obtained, but film forming property remains insufficient

Engineering Contradiction:

Improvefilm forming propertyVSAvoidsolvent content

Core Design Contradiction:

Manufacturing precisionVSQuantity of substance

Solution Approach 1:

The patent changes the solvent system parameters before solvent removal. By using a mixed solvent system of water and organic solvent, the resulting electroconductive polymer material inherently possesses better film forming properties after solvent removal. The organic solvent component leaves behind a polymer structure that forms uniform, well-adhered films, compensating for the loss of solvent content.

Inventive Principle:

Principle #35Parameter changes

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The resulting electroconductive polymer composition exhibits improved film forming properties and high electroconductivity, enabling the creation of solid electrolytic capacitors with high capacity and low ESR.

Implementation Method 1

an electroconductive polymer obtained by an oxidation polymerization by using an oxidant in a reaction solution

Methodology Applied

Scientific EffectOxidation polymerization: Oxidation

Implementation Method 2

a polyacid or a salt thereof as a dopant

Methodology Applied

Scientific EffectDoping: Dopants

Data Source

PatentUS9452594B2Electroconductive polymer composition, electroconductive polymer material, electroconductive substrate, electrode and solid electrolytic capacitor

Publication Date: 2016.09.27 TOKIN CORP

AI summary

Provided is an electroconductive polymer composition with a good film forming property and a high electroconductivity. Also, provided is an electroconductive polymer material and an electroconductive substrate with a high electroconductivity and transparency. Further, provided is a solid electrolytic capacitor with a high capacity and a low ESR. Disclosed is an electroconductive polymer composition, containing an electroconductive polymer obtained by an oxidation polymerization by using an oxidant in a reaction solution which contains at least one monomer selected from the group consisting of pyrrole, thiophene and derivatives thereof, a polyacid or a salt thereof as a dopant, and a solvent containing water and an aprotic solvent.