JR Centre for Recovery Strategies for Textiles

This JR Centre deals with one of the central topics for a more sustainable society: the recycling of textiles. Research is being conducted into processes for the gentle separation from mixed fabrics and the recovery of high-quality materials.

Textile fabrics are often blends of polyester and cotton ("polycotton"). These are to be separated into their components and recovered as high-quality raw materials. Two general recycling routes are being investigated: Firstly, polycotton is to be dissolved and separated into polyester (the PET fraction; polyethylene terephthalate) and cotton (the cellulose fraction) without excessively attacking their long-chain structures (polymers). In the second step, the fractions obtained are to be further processed: The cleaned PET fraction is processed into high-quality pellets in conventional PET recycling machines. The cellulose fraction, which corresponds to pure cotton, is to be treated in suitable processes so that it is suitable for the production of regenerated cellulose fibres.

In this way, a cycle is being established that will serve as a model for successful textile recycling and that can be extended to source materials with a more complex composition. Initial work phases include screening and characterising the source textiles and evaluating the requirements for recycling. A database of spectral analysis data will be created and processed using artificial intelligence (AI). Several pre-treatment methods and special cellulose solvents for the separation from cotton-rich articles are being tested. Enzymatic hydrolysis of cotton includes mechanical pretreatment of polycotton blends, chemical activation and evaluation of conditions for enzymatic separation and screening of optimised enzyme formulations.

The solvent/solvent systems are optimised in terms of selectivity and suitable conditions for minimal impact on polymer integrity with high cotton content. If the recovered PET is to be processed into new fibres, cellulose residues can interfere with this extrusion process. The cellulose residues in the PET fraction are therefore removed by selective dissolution and stabilised so that they can no longer disrupt the extrusion process. The processes will be scaled up to pilot scale.

All developments are accompanied by economic and ecological considerations, including life cycle analyses.