A new type of pure synthetic leather meets the high requirements of European ecological design regulations. It is made of bio based plastics, biodegradable, and meets the requirements of closed-loop recycling processes.

Many synthetic leathers are composed of a fabric substrate on which a polymer layer is applied. The polymer layer typically consists of an adhesive layer and a top layer that is typically embossed. Machine woven, knitted, or non-woven fabrics made of PET, PET/cotton, or polyamide are commonly used as fabric substrates. PVC and various polyurethanes are commonly used for coatings.

The use of these mature composite materials does not meet today's sustainability standards. The cost of recycling them by type is very high, even impossible. They are not biodegradable. Therefore, it is urgent to find alternative materials for producing synthetic leather. In 2022, the European Union passed the Sustainable Product Initiative (SPI) (Green Agreement). It includes an ecological design regulation that considers the product's lifecycle in the process of protecting resources. For textile and product design, this means incorporating closed-loop or scrapping into product development.

In the AiF project closely collaborated between DITF and Freiberg Institute gGmbH (FILK), a synthetic leather has now been developed where the fiber material and coating polymer are the same.

Aliphatic polyester polybutylene succinate (PBS) is recommended as a basic material due to its properties. PBS can be produced through biological sources, and there are currently multiple grades and large quantities available in the market. Its biodegradability has been confirmed in testing. This material can be subjected to thermoplastic processing; This applies to fiber materials and coatings. The characteristics of thermoplastic are beneficial for the recycling of subsequent products.

In order to achieve a successful spinning process and obtain PBS filament with good textile mechanical properties, process adjustments were made in the cooling shaft of DITF. Finally, POY yarns can be spun at a relatively high speed of up to 3000 meters per minute, and they have a strength slightly lower than 30cN/tex after stretching. Yarn can be easily processed into pure PBS fabric. FILK then uses it as a fabric substrate, and PBS can also be used as a thermoplastic for coating.

By optimizing the production steps, PBS composite materials with typical synthetic leather structures can be produced. Purity and biodegradability meet the requirements of closed-loop recovery process.