Textile Recycling Process for Polyester-Cotton Blend Depolymerization
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Solution Overview
Problem
Current recycling processes for polyester-cotton textiles are costly, time-consuming, and environmentally inefficient, often requiring shredding, depolymerization of polyester into monomers, and subsequent processing of cellulose pulp, which results in significant loss of cotton fiber quality and incomplete garment recycling due to the removal of non-textile elements.
Innovation Solution
A process that depolymerizes polyester in a basic aqueous solution under controlled conditions, allowing the recovery of cotton fibers as staple fibers without shredding or dissolving them into pulp, while keeping garments intact and removing non-textile elements, using a circulating depolymerization solution at specific temperature and pressure ranges to minimize cotton fiber degradation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If fabric is shredded before depolymerization, then polyester can be effectively depolymerized, but the process becomes time-consuming and costly
Solution Approach 1:
The patent applies preliminary action by treating the fabric with a depolymerization solution before shredding. The fabric is first subjected to chemical treatment that weakens the polyester structure, making subsequent mechanical shredding more efficient and reducing processing time. This sequence reversal of conventional processes (chemical treatment before mechanical processing) resolves the contradiction by preparing the material in advance to facilitate faster subsequent processing.
2Reliability
If cotton fibers are processed into pulp, then complete recycling is achieved, but fiber quality is significantly degraded
Solution Approach 1:
The patent applies the extraction principle by selectively removing polyester from the fabric matrix through depolymerization treatment, while leaving the cotton fiber structure intact. The depolymerization solution specifically targets polyester chains, breaking them down into soluble monomers that can be washed away, whereas the cellulose-based cotton fibers remain structurally preserved. This selective extraction achieves complete recycling of both components without degrading cotton fiber quality.
3Adaptability or versatility
If non-textile elements are removed before processing, then garment recycling is enabled, but additional processing steps are required
Solution Approach 1:
The patent applies merging by combining multiple processing objectives into a single integrated treatment step. The depolymerization process simultaneously achieves three functions: (1) breaks down polyester into soluble monomers, (2) detaches non-textile elements from the fabric matrix, and (3) preserves cotton fiber integrity. By consolidating these operations into one chemical treatment bath, the patent eliminates the need for separate pre-treatment steps for removing non-textile elements, thereby reducing overall process complexity.
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
This process effectively recycles cotton fibers with maintained mechanical properties, allowing them to be reused in yarn production without the need for additional chemical treatment, while also enabling the recycling of garments without pre-removal of non-textile elements, thus reducing waste and processing costs.
Implementation Method 1
a process for recycling waste blend fabrics comprising polyester and cellulosic fibres, preferably cotton fibres, the process including a depolymerization of the polyester in a basic aqueous solution
Data Source
AI summary
A process of treatment of waste blend textiles comprising polyester fibers and cotton fibres depolymerizes polyester in a controlled environment to obtain treated textile comprising cotton staple fibers suitable to be recycled into cotton yarns.