Polyamide Resin Composition Free Volume Control
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Solution Overview
Problem
Current polyamide resin compositions, such as those containing nylon 6 and N-MXD6, face challenges in achieving optimal gas-barrier performance, transparency, and moldability, especially in high-humidity environments, with existing additives like clay minerals and organic nucleating agents either compromising mechanical properties or worsening barrier performance.
Innovation Solution
A polyamide resin composition with a specific diamine unit, dicarboxylic acid unit, and a polysilsesquioxane modifier is developed, where the polysilsesquioxane with siloxane bonds is added to control the free volume of the resin to 0.0545 nm^3 or less, enhancing gas-barrier performance and maintaining moldability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If clay mineral is added to N-MXD6 to control crystal size and improve transparency, then visible light transmittance increases, but gas-barrier performance deteriorates
Solution Approach 1:
The patent uses an organic nucleating agent as an intermediary substance to control crystal size instead of clay mineral. This agent enables crystal growth control for transparency without the harmful effect on gas-barrier performance that clay mineral causes. The nucleating agent mediates between the need for small crystal sizes (for transparency) and the need to maintain good gas-barrier properties.
2Reliability
If inorganic substance such as talc or mica is blended with N-MXD6 to improve whitening resistance, then resistance to whitening after heating increases, but crystallization rate becomes too high causing poor moldability
Solution Approach 1:
The patent changes the chemical composition parameters by replacing inorganic substances (talc, mica) with specific organic nucleating agents. This parameter change allows control of crystallization rate to an appropriate level - fast enough for processing but not so fast as to cause premature crystallization during molding. The organic nucleating agent provides optimal crystallization kinetics that maintain both whitening resistance and moldability.
3Ease of operation
If other polyamide is mixed with N-MXD6 to improve flexibility and transparency, then film flexibility improves, but gas-barrier performance decreases
Solution Approach 1:
The patent replaces the mixture of N-MXD6 and other polyamides with a system using N-MXD6 plus organic nucleating agent. This substitution eliminates the need for blending different polyamides to achieve flexibility, as the organic nucleating agent system provides both flexibility and maintains the superior gas-barrier performance of pure N-MXD6.
4Illumination intensity
If clay mineral is added to control spherocrystal growth, then crystal size is reduced to improve transparency, but mechanical properties such as impact resistance deteriorate
Solution Approach 1:
The organic nucleating agent serves as a mediator that controls crystal size for transparency without the detrimental impact on mechanical properties that clay mineral causes. The organic agent interacts with the polymer matrix in a way that maintains both optical and mechanical performance, unlike the inorganic clay mineral which compromises impact resistance.
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 composition achieves improved gas-barrier performance against carbon dioxide and oxygen, maintains transparency, and preserves moldability, even in high-humidity conditions, by effectively controlling the free volume through the positron annihilation method.
Implementation Method 1
the polysilsesquioxane with siloxane bonds is added to control the free volume of the resin to 0.0545 nm^3 or less, enhancing gas-barrier performance
Implementation Method 2
a polysilsesquioxane modifier is developed, where the polysilsesquoxane with siloxane bonds is added
Implementation Method 3
by effectively controlling the free volume through the positron annihilation method
Data Source
AI summary
The invention provides a polyamide resin composition (1) containing a polyamide (A) and a free volume modifier (B), and having a free volume, as measured according to a positron annihilation method, of 0.0545 nm3 or less. The invention also provides a polyamide resin composition (2) prepared by adding from 0.005 to 1.200 parts by mass of a polysilsesquioxane (B) whose main chain is comprised of siloxane bonds, to 100 parts by mass of a polyamide (A) that contains a diamine unit including an aromatic diamine unit represented by the following general formula (I) in an amount of 70 mol % or more and a dicarboxylic acid unit including at least one of a linear aliphatic dicarboxylic acid unit represented by the following general formula (II-1) and an aromatic dicarboxylic acid unit represented by the following general formula (II-2) in a total amount of 50 mol % or more:wherein n in the general formula (II-1) indicates an integer of from 2 to 18, and Ar in the general formula (II-2) represents an arylene group.