Recyclable Polyamide-Polyether Filament for Elastic Textiles
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Solution Overview
Problem
Current elastic textile fibers, such as elastane, are not recyclable due to crosslinking, which prevents heat-fusibility, and alternative materials like polyesters and elastolefins have limited elasticity and are not compatible with polyamides.
Innovation Solution
Development of a recyclable elastic filament based on a polyamide-polyether block copolymer, specifically containing polyamide blocks from PA 11, PA 12, PA 1010, PA 1012, PA 1014, and polyether blocks derived from polytetramethylene glycol, with an enthalpy of fusion between 15 and 50 J/g, allowing for easy recycling and reuse.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If elastane fibers are used to achieve high elasticity and elastic return, then the elastic performance is improved, but the recyclability deteriorates due to crosslinking preventing heat-fusibility
Solution Approach 1:
The patent changes the chemical structure parameters of the elastane by replacing crosslinked polyurethane with a thermoplastic polyamide-polyether block copolymer. This structural parameter change enables heat-fusibility while maintaining elastic properties, allowing the material to be recycled through melting and reprocessing without losing its elastic functionality.
Solution Approach 2:
The invention uses a block copolymer composite structure combining polyamide blocks (providing heat-fusibility and recyclability) with polyether blocks (providing elasticity). This composite material approach integrates the beneficial properties of both polymer types, achieving both recyclability and high elastic return (>90%).
2Ease of manufacture
If alternative materials like polyester or elastolefin are used to improve recyclability, then the ease of recycling is improved, but the elasticity and compatibility with polyamides deteriorate
Solution Approach 1:
The block copolymer integrates polyamide and polyether segments at the molecular level, creating a single-phase material that is fully compatible with polyamide fibers during recycling. This eliminates the incompatibility issues of physical blends and ensures homogeneous melting and reprocessing while maintaining >90% elastic return.
Solution Approach 2:
The patent optimizes the molecular weight and block length parameters of both polyamide and polyether segments to achieve the desired balance between elasticity and processability. The polyether blocks provide elastic recovery while the polyamide blocks ensure heat-fusibility and compatibility with polyamide recycling streams.
3Ease of manufacture
If polyamide-polyether block copolymer is used to achieve recyclability and elasticity, then the ease of recycling and elastic return are improved, but the manufacturing complexity increases due to specific copolymer requirements
Solution Approach 1:
The copolymer is segmented into distinct polyamide and polyether blocks, each performing specific functions. This segmentation allows for controlled synthesis through step-growth polymerization of disocyanate, diol, and chain extenders, making the complex structure manufacturable through well-established polyurethane synthesis techniques adapted for thermoplastic applications.
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 filament maintains high elasticity, with an elastic return of over 90%, and can be recycled multiple times without significant degradation, resulting in a high-performance recycled product.
Implementation Method 1
the filament according to the invention has the advantage of being able to be recycled. Its rheological stability allows it to be easily remelted and reused
Implementation Method 2
an elastic return of greater than 90%
Data Source
AI summary
The invention relates to an elastic filament comprising a copolymer containing polyamide blocks and polyether blocks, —the polyamide blocks being chosen from PA 11, PA 12, PA 1010, PA 1012, PA 1014, the copolymer thereof and the mixture thereof, —the polyether blocks being blocks derived from polytetramethylene glycol having a weight-average molecular mass of between 500 and 3000 g/mol, —the enthalpy of fusion of the copolymer being between 15 and 50 J/g.