Transparent Copolyamide and Semicrystalline Polyamide Mixture
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Solution Overview
Problem
Existing polyamide moulding compositions face challenges with processability, chemical resistance, transparency, and haze, particularly in injection moulding, with known transparent copolyamides exhibiting inadequate chemical resistance and increased haze upon ageing in alcohols, and semicrystalline polyamides having high glass transition temperatures that hinder processing.
Innovation Solution
A novel polyamide moulding composition is developed, comprising a mixture of transparent copolyamides and semicrystalline aliphatic polyamides, specifically formulated to include cycloaliphatic and aliphatic diamines, aliphatic dicarboxylic acids, and additives, which improves toughness, chemical resistance, and processability, while maintaining excellent transparency and low haze, even upon ageing in alcohols.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If transparent copolyamides are used, then transparency and low haze are improved, but chemical resistance deteriorates
Solution Approach 1:
The patent employs a composite material system combining transparent copolyamides (amorphous phase) with semicrystalline polyamides in specific weight ratios (30-70% and 70-30 respectively). This composite approach leverages the transparency of the copolyamide component while the semicrystalline polyamide component provides the necessary chemical resistance, particularly against alcohols, resolving the contradiction between optical clarity and chemical durability.
2Reliability
If semicrystalline polyamides are used, then chemical resistance is improved, but processability deteriorates due to high glass transition temperatures
Solution Approach 1:
The patent modifies the thermal parameters of the semicrystalline polyamide component by selecting specific polyamides with glass transition temperatures below 80°C. This parameter change enables the material to be processed at lower temperatures, improving processability while maintaining the chemical resistance benefits of the semicrystalline structure through controlled crystallization behavior.
3Illumination intensity
If transparent copolyamides are used, then transparency is improved, but haze increases upon ageing in alcohols
Solution Approach 1:
The patent applies preliminary anti-action by incorporating the semicrystalline polyamide component that specifically resists alcohol attack before ageing occurs. This protective component prevents the alcohol-induced haze formation that would otherwise affect the transparent copolyamide, thereby maintaining optical clarity throughout the service life including after ageing in alcoholic environments.
Data Source
AI summary
A polyamide molding composition is described comprising the following components (A)-(C) in the following composition, where the entirety of components (A), (B) and (C) gives 100% by weight:(A) from 25 to 75% by weight of at least one transparent copolyamide composed of(a) from 50 to 90 mol % of a cycloaliphatic diamine selected from the group consisting of: bis(4-amino-3-methylcyclohexyl)methane (MACM), bis(4-aminocyclohexyl)methane (PACM), bis(4-amino-3-ethylcyclohexyl)methane (EACM), bis(4-amino-3,5-dimethylcyclohexyl)methane (TMACM) and mixtures thereof and(b) from 10 to 50 mol % of an unbranched, aliphatic diamine,based in each case on the total amount of diamines, and also(c) of one or more aliphatic and cycloaliphatic dicarboxylic acid(s),(B) from 25 to 75% by weight of at least one further polyamide of PAXY type, where X and Y can assume, independently of one another, the values from 9 to 14,(C) from 0 to 10% by weight of additives.