Polyamide Multilayer Structure for Recyclable Waterproof Breathability
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Solution Overview
Problem
Existing waterproof-breathable structures face challenges in recyclability due to the use of incompatible materials like PTFE and TPU membranes, leading to environmental impact and degraded product quality after recycling.
Innovation Solution
A multilayer structure comprising a textile layer and a film made of a copolymer with polyamide and polyether blocks, adhered via a copolyamide or a hot-melt adhesive, allowing for direct adhesion and recyclability without compromising performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If PTFE or TPU membranes are used to form waterproof-breathable films, then waterproofing and breathability performance is improved, but recyclability deteriorates due to material incompatibility and environmental impact
Solution Approach 1:
The patent applies homogeneity by using polyamide-based materials for both the textile layer and the film layer. The textile layer comprises polyamide fibers, and the film layer comprises a copolymer with polyamide blocks, ensuring material compatibility throughout the multilayer structure. This homogeneous material composition enables the entire structure to be recycled together without separation, resolving the recyclability issue while maintaining waterproof-breathable performance through the coordinated structure of polyamide textile and polyamide-based film.
Solution Approach 2:
The patent employs composite materials by creating a multilayer structure where a polyamide-based film is bonded to a polyamide textile layer using a polyamide hot-melt adhesive. The film itself is a composite copolymer containing both polyamide blocks (for strength and adhesion) and polyether blocks (for flexibility and breathability). This composite approach achieves the desired waterproof-breathable performance while ensuring all layers are compatible for recycling together as a single composite material system.
2Strength
If incompatible adhesives are used to bond the film to the textile layer, then bonding strength is improved, but recyclability deteriorates due to difficulty in separation and degraded product quality
Solution Approach 1:
The patent applies homogeneity by using polyamide hot-melt adhesive that is chemically compatible with both the polyamide textile layer and the polyamide-based film layer. This homogeneous adhesive system ensures strong bonding while allowing the entire multilayer structure to be recycled together without difficult separation processes, maintaining product quality after recycling.
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 structure maintains waterproof-breathable properties and facilitates recycling, ensuring performance comparable to pre-recycled products, thus addressing environmental and quality concerns.
Implementation Method 1
a film comprising at least one copolymer containing polyamide blocks and polyether blocks... the film adheres to the textile layer via a copolyamide
Implementation Method 2
barrier films that protect against liquids, in particular against water, notably waterproof breathable films
Implementation Method 3
ensure the transmission of water vapor... promoting breathability, so as to allow the evaporation of perspiration
Data Source
AI summary
The invention relates to a multilayer structure comprising a textile layer comprising at least one polymer chosen from a polyamide and a copolymer containing polyamide blocks and polyether blocks, and combinations thereof; and a film comprising at least one copolymer containing polyamide blocks and polyether blocks, the polyether blocks comprising polyethylene glycol blocks, the polyethylene glycol blocks representing at least 40% by mass relative to the mass of the film; in which the film adheres to the textile layer via a copolyamide.The invention also relates to a process for manufacturing said multilayer structure, to a process for recycling said multilayer structure and also to an article comprising said multilayer structure.