Polyamide Liner Structure for Pressure Vessel Collapse Resistance
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Pressure vessels made of polyamide resin experience collapse due to inward denting during depressurization, and there is a need for improved pressure resistance and gas barrier properties.
Innovation Solution
A liner containing a polyamide resin with specific regions of varying toughness improver content, where one region has 5 to 20% toughness improver and another region has 0.5% or less, combined with a xylylenediamine-based polyamide resin, enhances shape maintenance and gas barrier properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a polyamide resin liner is used in a pressure vessel, then gas barrier properties are improved, but collapse occurs during depressurization due to inward denting
Solution Approach 1:
The liner employs a multilayer structure where different regions have different toughness improver contents. The first region (5-20 mass% toughness improver) provides enhanced toughness and collapse resistance, while the second region (0.5 mass% or less toughness improver) maintains excellent gas barrier properties. This local differentiation resolves the contradiction between pressure resistance and gas barrier properties.
Solution Approach 2:
The liner is constructed as a composite material system combining polyamide resin with toughness improvers in specific proportions and distributions. The composite structure integrates the gas barrier properties of polyamide resin with the collapse resistance provided by toughness improvers, achieving both high reliability and pressure resistance simultaneously.
2Strength
If the liner is made entirely of high-toughness material to prevent collapse, then pressure resistance is improved, but gas barrier properties deteriorate
Solution Approach 1:
Instead of uniformly distributing toughness improvers throughout the liner, the invention concentrates them in the first region (5-20 mass%) while keeping the second region (0.5 mass% or less) essentially free of toughness improvers. This localized approach ensures collapse resistance where needed while preserving gas barrier properties in the region that contacts the stored gas.
3Strength
If uniform toughness improver distribution is used throughout the liner, then collapse resistance is improved, but manufacturing complexity increases and gas barrier properties are compromised
Solution Approach 1:
The liner is segmented into at least two distinct regions with different toughness improver contents. The first region contains 5-20 mass% toughness improver for collapse resistance, while the second region contains 0.5 mass% or less for gas barrier performance. This segmentation allows each region to fulfill its specific function without requiring complex overall structures.
Data Source
AI summary
To provide a liner which contains a polyamide resin, wherein the polyamide resin contains a diamine-derived structural unit and a dicarboxylic acid-derived structural unit; 50 mol % or more of the diamine-derived structural unit is derived from a xylylenediamine; a content of a toughness improver in a region up to 30% in a thickness direction from one surface of the liner is from 5 to 20 mass %; and a content of the toughness improver in a region up to 30% in a thickness direction from the other surface of the liner is 0.5 mass % or less.