Aqueous Polyimide Precursor via Imidazole Solvent Control

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Solution Overview

Problem

Existing methods for producing aqueous polyimide precursor solutions often require organic solvents, leading to environmental concerns and limitations in achieving high molecular weight polyimides with excellent properties like flexibility, heat resistance, and solvent resistance.

Innovation Solution

A method involving the reaction of a tetracarboxylic acid component and a diamine component in the presence of an imidazole using water as a solvent, with specific compositions of aromatic and aliphatic tetracarboxylic dianhydrides and diamines, to form an aqueous polyimide precursor solution with minimal organic solvent content.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If organic solvents are used to dissolve polyamic acid, then the polyimide precursor solution can be applied to substrate surfaces, but the environmental acceptability deteriorates and the method becomes less environmentally friendly

Engineering Contradiction:

Improveapplicability of polyimide precursor solutionVSAvoidenvironmental acceptability

Core Design Contradiction:

Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The invention changes the solvent parameter from organic to aqueous, using water as the solvent for polyamic acid. This is achieved by controlling the molecular weight of polyamic acid (10,000-1,000,000) and adjusting the concentration (5-50% by weight), which enables the polyamic acid to dissolve in water and form an applicable precursor solution without organic solvents, thus improving environmental acceptability while maintaining manufacturability

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The invention discards organic solvents from the system entirely, replacing them with water. By controlling the polyamic acid molecular weight within a specific range and using water as the solvent, the method eliminates harmful organic substances from the process, achieving both environmental friendliness and practical applicability

Inventive Principle:

Principle #34Discarding and recovering

2Strength

If high molecular weight polyimide is produced, then heat resistance and mechanical strength are improved, but solubility in organic solvents deteriorates making processing difficult

Engineering Contradiction:

Improvemechanical strengthVSAvoidsolubility and processability

Core Design Contradiction:

StrengthVSEase of manufacture

Solution Approach 1:

The invention changes the solvent system parameter from organic to aqueous, and controls the polyamic acid molecular weight parameter within 10,000-1,000,000. This parameter combination enables high molecular weight polyimide to be processed in aqueous solution, achieving both high mechanical strength and good processability without relying on organic solvent solubility

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The invention discards the dependency on organic solvent solubility by using water as the solvent. By controlling polyamic acid molecular weight and concentration, the method enables processing of high molecular weight polyimide in aqueous environment, eliminating the solubility limitation imposed by organic solvent requirements

Inventive Principle:

Principle #34Discarding and recovering

3Reliability

If polyamic acid solution is subjected to high temperature heat treatment, then dehydration/ring closure (imidization) is achieved, but the process becomes less environmentally friendly and application is limited

Engineering Contradiction:

Improvecompletion of imidization reactionVSAvoidenvironmental friendliness

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The invention changes the solvent parameter to water and controls polyamic acid molecular weight within 10,000-1,000,000. This enables the imidization reaction to proceed in an environmentally friendly aqueous system, achieving reliable polyimide formation without the need for harmful organic solvents while maintaining process reliability

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

This approach allows for the production of polyimides with enhanced properties such as flexibility, heat resistance, and solvent resistance, suitable for various applications including electrodes and flexible device substrates, while maintaining high environmental acceptability.

Implementation Method 1

a polyamic acid, which is formed by the reaction of a tetracarboxylic acid component and a diamine component

Methodology Applied

Scientific EffectChemical reaction: Chemical Bonding

Implementation Method 2

heating the solution composition at a high temperature to effect dehydration/ring closure (imidization)

Methodology Applied

Scientific EffectDehydration/ring closure (imidization): Chemical Bonding

Data Source

PatentUS11407857B2Method for producing aqueous polyimide precursor solution composition

Publication Date: 2022.08.09 UBE CORPORATION

AI summary

A method for producing an aqueous polyimide precursor solution composition includes forming a polyamic acid by the reaction of a tetracarboxylic acid component and a diamine component in an aqueous solvent together with an imidazole in an amount of 1.6 mole or more per mole of the tetracarboxylic acid component of the polyamic acid.