New bio-based polyester could solve problem of artificial leather recycling

Artificial leather is indispensable to the fashion industry – it helps avoid using animal leather and is often the base for accessories such as bags, belts and more, which meet the needs of an increasingly vegan clientele.

However, opinions on its environmental friendliness are divided – while some welcome the fact that there are versatile leather alternatives out there, others criticise the fact that synthetic leather often cannot do without a PVC backing.

However, much has changed since the first generation of artificial leathers, which were somewhat snidely referred to as “plastic leather” or “pleather”, came on the market. Today, there are wonderful alternatives made from apples, pineapples, mushrooms and more, which increasingly do without polymer layers, that is plastics.

Impurities complicate recycling

But there are vast differences between the different kinds of synthetic leather. One problem is that the textile backing (often woven, knitted or non-woven fabrics made of PET, PET/cotton or polyamide) and the polymer layer (usually PVC or various polyurethanes) that is applied are completely different materials. This no longer meets today's applicable sustainability criteria, such as the Ecodesign Directive, which is part of the EU Green Deal’s Sustainable Products Initiative (SPI).

Recycling these different materials cleanly is very complex, if not impossible. Nor are they biodegradable. The German Institute of Textile and Fiber Research (DITF) and the Freiberg Institute gGmbH (FILK) have cooperated to find a solution to this problem and succeeded in developing an artificial leather in which both the fibre material and the coating polymer are identical. This means that both materials are recyclable and thus meet the prerequisite for an industrial recycling concept.

Pure synthetic leather is biodegradable and recyclable

“Due to its properties, the aliphatic polyester polybutylene succinate (PBS) proved to be a suitable base material. PBS can be produced from biogenic sources and is now available on the market in several qualities and larger quantities. Its biodegradability has been proven in tests. The material can be processed thermoplastically. This applies to both the fiber material and the coating. Subsequent product recycling is simplified by the thermoplastic properties,” states a DIFT press release.

Successful primary spinning processes resulted in PBS filaments with good textile-mechanical properties, which were spun into pre-oriented yarns (POY). “The yarns could be easily processed into pure PBS fabrics,” reports DIFT. “With optimised production steps, PBS composite materials with the typical structure of artificial leather could be produced. Purity and biodegradability fulfil the requirements for a closed recycling process.”

Now, further yarn tests are needed, as well as an assessment of the synthetic leather's commercial viability.