Polyamide Multilayer Structure for Flexible Fuel Barrier Hoses
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Solution Overview
Problem
Existing multi-layer structures for fuel transportation pipes and hoses lack sufficient flexibility and gas barrier performance, particularly when used with alcohol gasoline, which is highly permeable and volatile, due to the low flexibility of xylylene-based polyamides and semi-aromatic polyamides.
Innovation Solution
A multi-layer structure comprising a polyamide layer (A) made from aliphatic polyamides like polyamide 11 or 12, and a polyamide layer (B) composed of xylylene-based polyamides, modified polyolefins, and aliphatic polyamides at specific proportions, with a modified polyolefin content of 5-15 parts by mass and polyamide content of 5-20 parts by mass per 100 parts of polyamide (B1), enhancing both chemical resistance and gas barrier performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If xylylene-based polyamides and semi-aromatic polyamides such as polyamide 9T are used as gas barrier layers, then gas barrier performance is improved, but flexibility deteriorates
Solution Approach 1:
The patent uses composite materials by combining xylylene-based polyamides (for gas barrier performance) with aliphatic polyamides and modified polyolefins (for flexibility). This creates a multi-component polyamide composition where each material contributes its advantageous properties, resolving the contradiction between gas barrier performance and flexibility.
Solution Approach 2:
The patent applies local quality by creating a multi-layer structure where different polyamide compositions are assigned to different layers. The gas barrier layer contains high xylylene-based polyamide content for excellent barrier properties, while other layers have optimized compositions for flexibility and toughness, allowing each layer to perform its specific function optimally.
2Ease of operation
If aliphatic polyamides such as polyamide 11 and polyamide 12 are used, then flexibility and chemical resistance are improved, but gas barrier performance deteriorates
Solution Approach 1:
The patent combines aliphatic polyamides (providing flexibility and chemical resistance) with xylylene-based polyamides and modified polyolefins (providing gas barrier performance) in a composite polyamide composition. This composite approach allows the material to simultaneously exhibit flexibility from aliphatic polyamides and gas barrier properties from xylylene-based components.
Solution Approach 2:
The patent merges multiple polyamide types (aliphatic polyamides, xylylene-based polyamides, and modified polyolefins) into a single integrated polyamide composition. This merging allows the composition to inherit and combine the beneficial properties of each component: flexibility from aliphatic polyamides, gas barrier performance from xylylene-based polyamides, and enhanced chemical resistance from the synergistic combination.
3Reliability
If a multi-layer structure with gas barrier layer containing xylylene-based polyamide and semi-aromatic polyamide is created, then gas barrier performance is improved, but flexibility and practical usability deteriorate
Solution Approach 1:
The patent applies local quality by optimizing the polyamide composition for each specific layer's function. The gas barrier layer contains high xylylene-based polyamide content (70-100 mass%) for excellent barrier properties, while other layers have compositions optimized for flexibility and toughness. This localized optimization allows the overall structure to be practically usable while maintaining high gas barrier performance.
Solution Approach 2:
The patent uses composite materials in the multi-layer structure, where each layer is made from a composite polyamide composition tailored to its specific function. This allows the structure to achieve both high gas barrier performance in the barrier layer and good flexibility/practical usability in other layers, resolving the contradiction between barrier performance and practical usability.
Data Source
AI summary
The present invention provides a multi-layer structure having: a polyamide layer (A) comprising a composition containing an aliphatic polyamide such as a polyamide including C10-12 lactam-derived constituent units and/or C10-12 aminocarboxylic acid-derived constituent units; and a polyamide layer (B) comprising a composition containing, in a predetermined amount ratio, an aliphatic polyamide such as a polyamide including diamine units including at least 70 mol% of xylylenediamine-derived constituent units and dicarboxylic acid units including at least 70 mol% of C4-12 aliphatic dicarboxylic acid-derived constituent units, or a polyamide including a modified polyolefin and C6-12 lactam-derived constituent units and/or C6-12 aminocarboxylic acid-derived constituent units. According to a preferred embodiment of the present invention, this multi-layer structure has excellent flexibility as well as exceptional chemical resistance and gas barrier performance.