Polyester–Spandex Waste Fabric Recycling via Oxidative Elution
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Solution Overview
Problem
Existing methods for recycling polyester and spandex fibers in waste fabrics are inefficient and require high amounts of cosolvents, leading to poor decolorization and reduced recycling quality.
Innovation Solution
A disposal method involving a first-stage treatment with a cosolvent and oxidant to separate and decolorize waste fabric, followed by multiple elution stages to recover high-quality recycled polyester and spandex, reducing cosolvent usage and improving recycling efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If conventional elution methods are used to separate polyester and spandex, then the fibers can be separated, but high amounts of cosolvents are required and decolorization is poor
Solution Approach 1:
The patent changes the chemical parameters of the elution system by introducing oxidants (such as hydrogen peroxide, sodium hypochlorite, or ozone) into the cosolvent mixture. This parameter change enables simultaneous decolorization and separation, improving hue quality from L* 57 to L* 75-85 while reducing cosolvent consumption through enhanced reaction efficiency
Solution Approach 2:
The patent creates a composite elution system combining cosolvents (dimethylformamide and water) with oxidants. This composite approach allows the system to perform multiple functions: spandex dissolution, polyester separation, and dye decolorization simultaneously, resolving the contradiction between solvent reduction and decolorization quality
2Productivity
If multiple elution stages are performed to improve separation quality, then recycling yield increases, but process complexity increases
Solution Approach 1:
The patent divides the recycling process into two distinct stages: a first-stage treatment with cosolvent and oxidant for initial separation and decolorization, followed by additional elution stages for further purification. This segmentation allows systematic optimization of each stage, achieving high recycling yield (90-95%) while managing process complexity through structured progression
Solution Approach 2:
The first-stage treatment performs preliminary decolorization and separation using oxidants before subsequent elution stages. This preliminary action removes the majority of dyes and separates fibers effectively, reducing the burden on later stages and enabling high overall yield without excessive complexity in each individual stage
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 method significantly reduces cosolvent usage, enhances the quality of recycled polyester and spandex, and increases the overall recycling yield by effectively decolorizing and separating the materials.
Implementation Method 1
decolorization, including the physical removal of dyes from fibers and the removal of chromophores, of the oxidant may be improved in an environment of cosolvents
Implementation Method 2
performing a first-stage treatment including elution on the waste fabric to obtain a first liquid material and a first solid material
Data Source
AI summary
A disposal method for waste fabric containing polyester, spandex, and dye includes the following steps: step (a): providing a waste fabric containing polyester, spandex, and dye; and step (b): performing a first-stage treatment including elution on the waste fabric to obtain a first liquid material and a first solid material. The first-stage treatment includes elution with a cosolvent mixed with an oxidant. The first solid material includes recycled polyester, and/or the first liquid material includes recycled spandex or degraded spandex.