A new type of pure synthetic leather which meets the high requirements of the European Ecodesign Regulation has been developed in a joint project between the German Institutes of Textile and Fibre Research Denkendorf (DITF) and the Freiberg Institute (FILK).

Made from a bio-based plastic, it is biodegradable and meets the requirements for a closed recycling process.

Many synthetic leathers consist of a textile substrate to which a polymer layer is applied. The polymer layer usually consists of an adhesive layer and a top layer, which is generally embossed.

The textile backing and the top coat are usually completely different materials. Woven, knitted, or nonwoven fabrics made of PET, PET/cotton, or polyamide are often used as textile substrates, with PVC and various polyurethanes are commonly used for coatings.

The use of these established composite materials does not meet today’s sustainability criteria since recycling them by type is very costly or even impossible and they are not biodegradable.

The search for alternative materials for the production of artificial leather is therefore urgent, since in 2022, the EU adopted the Sustainable Products Initiative which includes an eco-design regulation that considers a product’s life cycle in the conservation of resources. For textile and product design, this means incorporating closed loop or viable end-of-life options.

For the new material, the project selected aliphatic polyester polybutylene succinate (PBS). PBS can be produced from biogenic sources and is now available on the market in several grades and in large quantities. Its biodegradability has been demonstrated in tests and it can be processed thermoplastically as both the fibre material and the coating.

In order to realise a successful primary spinning process and to obtain PBS filaments with good textile mechanical properties, process adjustments had to be made in the cooling shaft of the DITF’s spinning system. These subsequently enabled POY yarns to be spun at relatively high speeds of up to 3,000 m/min, with a tenacity of just under 30 cN/tex when stretched. The yarns could be easily processed into pure PBS fabrics.

The fabrics were then  used by FILK as a textile base substrate for the subsequent extrusion coating, where PBS was also used as a thermoplastic.

With optimised production steps, PBS composite materials with the typical structure of artificial leather have been produced with the purity and biodegradability to fulfil the requirements for a closed recycling process.

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