Multilayer Container Polyamide Resin Composition
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Solution Overview
Problem
Multilayer containers with polyester and polyamide layers face delamination issues due to insufficient gas barrier properties and impact resistance, particularly when using polyamide resins composed of metaxylylenediamine and adipic acid.
Innovation Solution
A multilayer container design with a polyester innermost layer and a polyamide interlayer, where the polyamide resin consists of 70 mol% xylylenediamine and 70 mol% α,ω-linear aliphatic dicarboxylic acid, and a specific stretching ratio in the transverse direction of 2.2 times or more, along with a machine direction to transverse direction stretching ratio of 0.6 to 1.0, is employed to enhance oxygen barrier properties and delamination resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a polyamide resin composed of metaxylylenediamine and adipic acid is used as a barrier layer, then oxygen barrier property is improved, but delamination resistance deteriorates due to impact from outside
Solution Approach 1:
The invention changes the chemical composition parameters of the polyamide resin by specifying that it must contain a structural unit derived from xylylenediamine (70-100 mol %) and a structural unit derived from an α,ω-linear aliphatic dicarboxylic acid having 4 to 20 carbon atoms (70-100 mol %). This specific compositional parameter range resolves the contradiction by achieving both excellent oxygen barrier properties and delamination resistance simultaneously
Solution Approach 2:
The invention uses a composite material approach by creating a multilayer container with a polyester layer and a polyamide layer, where the polyamide layer serves as both the barrier layer and interlayer. The specific polyamide resin composition (xylylenediamine-based with α,ω-linear aliphatic dicarboxylic acid) creates a composite structure that provides both gas barrier properties and interlayer adhesion, preventing delamination while maintaining oxygen barrier performance
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 solution provides a multilayer container with improved oxygen barrier properties and excellent delamination resistance, achieved through controlled stretching and orientation of the polyamide layer, which increases residual stress and suppresses delamination points.
Implementation Method 1
a stretching ratio in a transverse direction (TD) is 2.2 times or more, and a stretching ratio in a machine direction (MD) to the stretching ratio in the transverse direction (TD) (MD/TD) is 0.6 or more and less than 1.0
Data Source
AI summary
A multilayer container having a polyester layer comprising a thermoplastic polyester resin (X) and a polyamide layer comprising a polyamide resin (Y), wherein the polyester layer is an innermost layer and the polyamide layer is an interlayer, and the polyamide resin (Y) comprises a polyamide resin (Y-1) comprising a structural unit derived from a diamine and a structural unit derived from a dicarboxylic acid, 70 mol % or more of the structural unit derived from a diamine being a structural unit derived from xylylenediamine; and 70 mol % or more of the structural unit derived from a dicarboxylic acid being a structural unit derived from an α,ω-linear aliphatic dicarboxylic acid having 4 to 20 carbon atoms, and wherein a stretching ratio in a transverse direction (TD) is 2.2 times or more, and a stretching ratio in a machine direction (MD) to the stretching ratio in the transverse direction (TD) (MD/TD) is 0.6 or more and less than 1.0.