Solvolysis trial launched in Germany

Recycling mixed waste textile fibres by a continuous chemical process using solvolysis is being trialled in Germany.

Plastic research specialist SKZ is working with the Fraunhofer Institute for Manufacturing Technology and Applied Materials Research on the CloseT project to develop a commercially viable solution.

Until now, end-of-life textiles have mainly been recycled thermally, which destroys valuable polymer resources and prevents the opportunity for rebuilding plastics.

Continuous process

The CloseT project focuses on chemical recycling using solvolysis to create new monomers from polymers. This involves chemically recycling mixed old textile fibres in a continuous process using a twin-screw extruder. The reaction products obtained in the recycling process are to be used directly as raw materials in plastics processing.

‘We want to create a sustainable alternative that not only conserves resources but also opens up new value chains,’ explains Hatice Malatyali, project manager at SKZ.

‘With this project, we are making an important contribution to reducing textile waste and strengthening the circular economy,’ says Andreas Hartwig from the Fraunhofer Institute.

Volkswagen Foundation

Suitable synthesis routes are being developed in the laboratory and then transferred to the continuous process. One focus is on the efficient separation of mixed fibres such as cotton and PET. Cellulose acetate is to be produced from the cellulose fibres obtained, while the degraded PET fractions are repolymerised to rPET.

The CloseT project is being funded by the Volkswagen Foundation until October 2029 through its Circularity with Recycled and Biogenic Raw Materials funding initiative.