Water-Based Polyimide Preparation via Monomeric Salt Polycondensation
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Solution Overview
Problem
Existing polyimide synthesis processes require high energy input due to high viscosities at low concentrations and high temperatures, limiting their efficiency and applicability, particularly for energy-efficient wire varnish production.
Innovation Solution
A method involving the mixing of polycarboxylic acid or its anhydride with a diamine compound in a polar protic solvent to form a monomeric salt, followed by isolation and addition to an aqueous solution with a co-solvent at controlled temperature and surface tension, then treating under latent conditions to obtain a water-based polyimide.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by stationary object
If polyimide synthesis is carried out in solution or molten state using conventional methods, then polyimide can be obtained, but high energy input is required due to high temperatures or dehydrating agents
Solution Approach 1:
The invention changes the chemical parameters of the reaction system by using monomeric salts instead of conventional monomers, allowing the polycondensation to proceed at room temperature or moderate temperatures without requiring high energy input or dehydrating agents
Solution Approach 2:
The invention introduces monomeric salts as an intermediary substance that facilitates the polycondensation reaction under mild conditions, avoiding the need for high temperatures or aggressive dehydrating agents while still enabling efficient polyimide formation
2Ease of operation
If polyimide processing is carried out at low concentrations, then viscosity is reduced, but productivity decreases due to lower monomer concentration
Solution Approach 1:
The invention changes the concentration parameter by enabling effective polycondensation at higher monomer concentrations (5-20% w/w) through the use of monomeric salts, thereby improving productivity while maintaining acceptable viscosity levels through the aqueous reaction medium
3Productivity
If high temperatures are used for thermal condensation of polyamic acid, then polyimide is obtained efficiently, but energy consumption increases significantly
Solution Approach 1:
The invention performs preliminary action by pre-forming monomeric salts before the polycondensation step, which enables the subsequent polyimide formation to proceed at room temperature or moderate temperatures without requiring high-temperature thermal condensation, thus maintaining reaction efficiency while dramatically reducing energy consumption
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 process reduces energy consumption and enables the production of water-based polyimides suitable for wire varnish applications with improved rheological properties and coating performance.
Implementation Method 1
mixing a polycarboxylic acid or an anhydride thereof with a diamine compound in a polar protic solvent to yield a monomeric salt
Implementation Method 2
the surface tension of the solution is adjusted to be in the range of 28 to 40 mN/m
Implementation Method 3
adding the monomeric salt stepwise to an aqueous solution comprising water and a co-solvent
Implementation Method 4
treating the solution under latent conditions until the polyimide is obtained
Data Source
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AI summary
The present invention relates to a novel process for preparing water-based polyimides from a polycarboxylic acid or its anhydride compound and a diamine compound.