Electroconductive Polymer Dispersion Liquid with Silane Crosslinking

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Solution Overview

Problem

Existing electroconductive polymer dispersion liquids fail to achieve excellent electrical conductivity, heat resistance, moist-heat resistance, and substrate adhesion properties, particularly when using π-conjugated electrically conductive polymers like polypyrrole, polythiophene, and polyaniline, which are typically insoluble and difficult to form into uniform coatings.

Innovation Solution

An electroconductive polymer dispersion liquid comprising a π-conjugated electrically conductive polymer, a polyanion, a specific compound represented by the chemical formula CH2═C(R1)—CO—NH—R2—O—CO—NH—R3—Si(OR4)3, and a dispersion medium, along with a binder resin, to form a complex that enhances electrical conductivity, heat resistance, and substrate adhesion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a π-conjugated electrically conductive polymer is used to form a coating, then electrical conductivity is improved, but substrate adhesion property deteriorates

Engineering Contradiction:
Improveelectrical conductivityVSAvoidsubstrate adhesion property
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The patent introduces a silane crosslinking agent as an intermediary substance that mediates between the π-conjugated electrically conductive polymer and the substrate. The silane compound forms crosslinking bonds with both the polymer and the substrate surface, creating a strong adhesive interface while maintaining the electrical conductivity of the polymer coating.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent creates a composite coating system comprising the π-conjugated electrically conductive polymer, polyanion, silane crosslinking agent, and binder resin. This composite structure combines the electrical conductivity of the polymer with the adhesion properties of the silane-crosslinked network and binder resin, achieving both improved conductivity and substrate adhesion simultaneously.

Inventive Principle:
Principle #40Composite materials

2Reliability

If a π-conjugated electrically conductive polymer is used to form a coating, then electrical conductivity is improved, but heat resistance deteriorates

Engineering Contradiction:
Improveelectrical conductivityVSAvoidheat resistance
Core Design Contradiction:
ReliabilityVSTemperature

Solution Approach 1:

The patent forms a composite coating structure where the silane crosslinking agent creates a thermally stable crosslinked network that reinforces the polymer matrix. This crosslinked composite structure maintains electrical conductivity while providing enhanced heat resistance through the thermal stability of the silane-crosslinked bonds and binder resin matrix.

Inventive Principle:
Principle #40Composite materials

3Ease of manufacture

If a π-conjugated electrically conductive polymer is coordinated with a polyanion to enable dispersion, then ease of manufacture is improved, but electrical conductivity deteriorates

Engineering Contradiction:
ImprovedispersibilityVSAvoidelectrical conductivity
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent optimizes the molecular weight, charge density, and ratio of polyanion to polymer to achieve the right balance between dispersibility and conductivity. By carefully controlling these parameters, the polyanion provides sufficient dispersion without excessively doping the polymer and reducing its electrical conductivity.

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 proposed solution enables the formation of electroconductive coatings with improved electrical conductivity, heat resistance, and substrate adhesion, maintaining these properties even under high temperature and moist conditions, with surface resistivity of 600 Ω/sq or less and minimal peeling, thus addressing the inadequacies of previous coatings.

Implementation Method 1

a π-conjugated electrically conductive polymer and a polyanion

Methodology Applied
Scientific EffectCoordination:

Implementation Method 2

a specific compound for forming a crosslinking point is contained in the dispersion liquid

Methodology Applied
Scientific EffectCrosslinking:

Implementation Method 3

π-conjugated electrically conductive polymer such as polypyrrole, polythiophene and polyaniline is used as an antistatic agent, a transparent conductive film or an electrode of a capacitor

Methodology Applied
Scientific EffectElectrical conduction: Conduction (electrical)

Data Source

PatentUS9640296B2Electroconductive polymer dispersion liquid and electroconductive coating
Publication Date: 2017.05.02 SHIN ETSU POLYMER CO LTD

AI summary

The present invention relates to an electroconductive polymer dispersion liquid characterized in containing a π-conjugated electrically conductive polymer, a polyanion, a compound represented by the following chemical formula (1), and a dispersion medium. In accordance with the present invention, an electroconductive polymer dispersion liquid capable of readily forming an electroconductive coating having excellent electrical conductivity, heat resistance, moist-heat resistance, and substrate adhesion property can be provided.[Chemical formula 1]CH2═C(R1)—CO—NH—R2—O—CO—NH—R3—Si(OR4)3  (1)In chemical formula (1), R1 represents a hydrogen atom or a methyl group, R2 and R3 each independently represent an arbitrary substituent group, and R4 represents a methyl group or an ethyl group.