10T/6T Copolyamide Compositions for Heat Resistance and Low Water Absorption
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Solution Overview
Problem
Standard polyamides face issues with high water absorption, which affects dimensional stability and mechanical properties, especially under wet or moist conditions, and existing semiaromatic polyamides either have high melting points or poor processability.
Innovation Solution
A polyamide molding composition comprising 30 to 100% 10T/6T copolyamide with specific molar ratios of 1,10-decanediamine and 1,6-hexanediamine, reinforced with glass or carbon fibers, and additives like phosphinic salts and melamine derivatives, achieving low water absorption and high heat deflection temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If standard polyamides (PA6, PA66) are used, then high melting points and high heat deflection temperatures are achieved, but water absorption becomes too high (up to 10%), affecting dimensional stability and mechanical properties
Solution Approach 1:
The patent uses copolyamides composed of multiple diamine and dicarboxylic acid components (PA6T/66/6I, PA6T/6T/6I, PA6T/6T/6) to create a composite material structure that combines the high heat resistance of aromatic polyamides with the low water absorption of aliphatic polyamides, achieving both high heat deflection temperature and low water absorption simultaneously
Solution Approach 2:
The patent changes the chemical composition parameters by specifying precise molar ratios of different monomers (e.g., 40-70 mol% PA6T, 10-30 mol% PA66, 10-30 mol% PA6I) to optimize the balance between heat resistance and water absorption, creating a copolymer with tailored properties
2Quantity of substance
If semiaromatic polyamides (PA6T/6I) are used, then water absorption is reduced, but melting points become too high and processability deteriorates
Solution Approach 1:
The patent changes the compositional parameters by incorporating aliphatic diamines (1,6-hexanediamine, 1,12-dodecanediamine) and dicarboxylic acids (adipic acid, isophthalic acid) in specific ratios to lower the melting point from above 300°C to 240-280°C, improving processability while maintaining low water absorption through the aromatic components
3Quantity of substance
If PA10T is used, then water absorption is markedly reduced and crystallinity is high, but freezing occurs within the nozzle during injection molding
Solution Approach 1:
The patent changes the compositional parameters by copolymerizing PA10T with other polyamides (PA6T, PA66, PA6I) to adjust the melting point and crystallization behavior, preventing nozzle freezing while maintaining low water absorption through the optimized copolymer composition
4Strength
If glass-fiber-reinforced PA10T is used, then mechanical properties are improved, but surface quality becomes very irregular
Solution Approach 1:
The patent uses a multi-component copolymer matrix (PA6T/66/6I, PA6T/6T/6I, or PA6T/6T/6) combined with glass fiber reinforcement to create a composite material that provides both enhanced mechanical properties and improved surface quality compared to PA10T, through the optimized polymer matrix composition
Data Source
AI summary
A polyamide molding composition having the constitution from 30 to 100% by weight of at least one 10T/6T copolyamide composed of from 40 to 95 mol % of 10T units, and from 5 to 60 mol % of 6T units, from 0 to 70% by weight of reinforcing materials and/or fillers, and from 0 to 50% by weight of additives and/or further polymers. Uses and processes for the preparation of this polyamide molding composition are described.