Sebacic Acid Purity Control for Polyamide Resin Coloration
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Solution Overview
Problem
Polyamide resins produced using sebacic acid as a dicarboxylic acid component often exhibit yellowish coloration due to minor impurities present in the sebacic acid.
Innovation Solution
Using a specific sebacic acid with a total content of compounds represented by general formulas (A) and (B) of 100 ppm by mass or less, and a purity of 99.5% by mass or more, to reduce coloration in the polyamide resin production process, which involves reacting sebacic acid in amounts of 50 mol% or more with xylylenediamine in amounts of 70 mol% or more.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If sebacic acid is used as a dicarboxylic acid component to produce polyamide resin, then the polyamide resin exhibits low water absorbability and excellent dimensional stability, but the resultant polyamide resin is often colored (yellowish coloration)
Solution Approach 1:
The patent applies parameter changes by specifying precise purity thresholds (99.5% or more) and impurity concentration limits (100 ppm or less of compounds represented by formulas (A) and (B)) for sebacic acid. This quantitative parameter control resolves the contradiction by identifying that coloration is caused by specific impurity compounds, and by setting strict parameter limits on these impurities, the patent achieves both low coloration (yellow index of 5 or less) and maintains the dimensional stability benefits of using sebacic acid.
2Reliability
If sebacic acid is used as a dicarboxylic acid component to produce polyamide resin, then the polyamide resin exhibits low water absorbability, but the resultant polyamide resin is often colored (yellowish coloration)
Solution Approach 1:
The patent resolves this contradiction by changing the purity parameters of the sebacic acid原料. By specifying that sebacic acid must have a purity of 99.5% or more and contain 100 ppm or less of compounds represented by formulas (A) and (B), the patent simultaneously achieves low water absorbability (inherent property of polyamide from sebacic acid) and low coloration (yellow index of 5 or less).
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 method effectively reduces the coloration of the polyamide resin, achieving a yellow index of 5 or less, while maintaining excellent mechanical properties and dimensional stability.
Implementation Method 1
reacting a dicarboxylic acid component containing sebacic acid in an amount of 50 mol% or more and a diamine component containing xylylenediamine in an amount of 70 mol% or more
Data Source
AI summary
Provided is a method for producing a polyamide resin including reacting a dicarboxylic acid component containing sebacic acid in an amount of 50 mol% or more and a diamine component containing xylylenediamine in an amount of 70 mol% or more, wherein the total content of the specific compounds in the sebacic acid is 100 ppm by mass or less.