Diacid Diamine Salt Solution Dissolution Process
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Solution Overview
Problem
Existing processes for manufacturing solutions of diacid and diamine salts for polyamide production face issues with dissolution of monomers, leading to problems with productive output, quality, storage, and transportation, particularly when using copolyamides with aromatic diacids and hexamethylenediamine.
Innovation Solution
A process involving the controlled mixing of diacids and diamines in an aqueous solution at specific temperature ranges and molar ratios, with controlled flow rates and heat management, to achieve a diacid/diamine molar ratio between 0.9 and 1.1, ensuring efficient dissolution and concentration of the salt solution between 40% and 70% by weight.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If diacids and diamines are mixed in aqueous medium to form salt solution, then polyamide production is enabled, but dissolution problems occur with copolyamides containing aromatic diacids
Solution Approach 1:
The patent applies preliminary action by pre-dissolving the diacid in the diamine solution before the actual polymerization reaction. This preliminary dissolution step ensures that aromatic diacids, which are difficult to dissolve, are fully incorporated into the aqueous medium beforehand, preventing dissolution problems during subsequent polymerization and maintaining high productive output.
Solution Approach 2:
The patent utilizes parameter changes by adjusting the concentration of the diamine solution (using concentrated solutions with high diamine content) and controlling the addition rate of diacid. By changing these parameters, the patent achieves complete dissolution of aromatic diacids while maintaining productivity and avoiding solid phase formation during the polymerization process.
2Productivity
If concentrated salt solutions are used to increase production efficiency, then productivity improves, but dissolution problems and solid phase formation occur
Solution Approach 1:
The patent applies preliminary action by pre-dissolving the diacid in the diamine solution before the actual polymerization reaction. This preliminary dissolution step ensures that aromatic diacids, which are difficult to dissolve, are fully incorporated into the aqueous medium beforehand, preventing dissolution problems during subsequent polymerization and maintaining high productive output.
Solution Approach 2:
The patent utilizes parameter changes by adjusting the concentration of the diamine solution (using concentrated solutions with high diamine content) and controlling the addition rate of diacid. By changing these parameters, the patent achieves complete dissolution of aromatic diacids while maintaining productivity and avoiding solid phase formation during the polymerization process.
3Reliability
If dissolution time is extended to ensure complete dissolution, then quality improves, but productive output decreases
Solution Approach 1:
The patent applies preliminary action by pre-dissolving the diacid in the diamine solution before the actual polymerization reaction. This preliminary dissolution step ensures that aromatic diacids, which are difficult to dissolve, are fully incorporated into the aqueous medium beforehand, preventing dissolution problems during subsequent polymerization and maintaining high productive output.
Solution Approach 2:
The patent utilizes parameter changes by adjusting the concentration of the diamine solution (using concentrated solutions with high diamine content) and controlling the addition rate of diacid. By changing these parameters, the patent achieves complete dissolution of aromatic diacids while maintaining productivity and avoiding solid phase formation during the polymerization process.
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 ensures effective dissolution of diacids, prevents solid phase formation, and achieves the desired concentration and composition of the salt solution, enhancing productivity and quality while facilitating storage and transportation.
Implementation Method 1
adding the adipic acid to hexamethylenediamine, or vice versa, in the aqueous medium, while removing or not removing the heat produced by the neutralisation reaction
Implementation Method 2
This solution is heated in order to evaporate the water, in a first step, and then in order to start the polymerisation by polycondensation
Implementation Method 3
start the polymerisation by polycondensation, in order to obtain macromolecular chains comprising amide functional groups
Data Source
AI summary
A method for manufacturing a solution of a diacid and diamine salt for manufacturing polyamide is described. A method for manufacturing an aqueous solution of diacid and diamine salts produced by mixing at least two diacids and at least one diamine, with a weight concentration of salt between 40% and 70%, including, in a first step, preparing an aqueous solution of diacid(s) and diamine(s) with a diacid/diamine mole ratio of less than 1 using one diacid and one diamine, and in a second step, adjusting the mole ratio of diacids/diamine(s) to a value of between 0.9 and 1.1, and fixing the weight concentration of salt by adding another diacid and, optionally, additional water and/or diamine is also described.