Germany’s DITF & FILK use bio-based PBS to create synthetic leather

It is now feasible to create synthetic leather in which the coating polymer and the fiber material are the same thanks to an AiF initiative conducted in close collaboration with the Freiberg Institute (FILK) and the German Institutes of Textile and Fiber Research Denkendorf (DITF). The industrial recycling idea requires the varietal purity.
A polymer layer is placed to a textile substrate to create many synthetic leathers. Typically, the polymer layer is composed of two layers: an adhesive layer and an embossed top layer. Typically, the top coat and the textile backing are made of entirely distinct materials. Textile substrates such as PET, PET/cotton, or polyamide can be woven, knitted, or nonwoven.

Coatings made of PVC and other polyurethanes are widely used. The current sustainability standards are not met by the usage of these well-established composite materials. Sorting and recycling them is exceedingly expensive, if not impossible. They don’t break down naturally. Therefore, it is imperative to look for substitute materials for making artificial leather. The Sustainable Products Initiative (SPI) (Green Deal) was accepted by the EU in 2022. It has an eco-design rule that takes resource conservation into account throughout a product’s life cycle.

This entails integrating end-of-life or closing the loop into product creation for textile and product design. Because of its qualities, aliphatic polyester polybutylene succinate (PBS) was suggested as the foundation material. PBS is currently offered in a variety of grades in big quantities on the market. It can be made from biogenic sources. Tests have confirmed its biodegradability. The material is amenable to thermoplastic processing. This holds true for the coating as well as the fiber substance. Thermoplastic qualities enable easier product recycling in the future, according to DITF’s website.

Process modifications had to be done in the cooling shaft at the DITF in order to achieve a successful primary spinning process and PBS filaments with good textile mechanical qualities. In the end, POY yarns with a tenacity of slightly less than 30 cN/tex when stretched could be spun at comparatively high speeds of up to 3,000 m/min. Pure PBS fabrics might be easily made from the yarns. PBS was also utilized as a thermoplastic in these, and they were subsequently employed at FILK as a textile foundation substrate for the ensuing extrusion coating.

PBS composite materials with the usual structure of fake leather could be manufactured using optimized production methods. Biodegradability and purity satisfy the conditions for a closed recycling process.

 

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