Is the circular economy also making its way into the fashion industry? Researchers and fashion producers from five countries want to revolutionize the industry together. Dr. Andreas Bartl explains why this is important: "Currently, only a few EU countries have separate collection systems for end-of-life textiles. These collection systems are financed by the sale of re-useable items and therefore the system focusses only on second-hand clothes (SHC). By 2025 at the latest, an EU directive will stipulate the separate collection of end-of-life textiles, including those that are not suitable for reuse. Economically and ecologically operating recycling systems, however, are not yet developed and implemented." - This is one of the goals of SCIRT (System Circularity & Innovative Recycling of Textiles). In addition, the design of the garments will be evaluated and the service life of textiles will be increased through suitable material combinations.
To allow the pants to become a shirt
The use of recycled materials is already common practice in the fashion industry. However, polyester (PET) fibers are rather obtained from beverage bottles than from end-of-life clothing. "Fiber manufacturers consume about three-quarters of the granulate derived from end-of-life PET bottles. Thus, about 15% of PET fibers are based on recycled material. However, only about one percent of end-of-life garments are fed back into the textile processing chain," says Bartl, a scientist from the Research Group for Particle Technology, Recycling Technology and Technology Assessment who works on the SCIRT project with Emanuel Boschmeier and Wolfgang Ipsmiller.
Just a few years ago, recycling was not an issue in the fashion industry. The reason for this is sometimes that recycling fibers is more expensive than producing them from scratch. Therefore, not only is there a need for legal measures as currently being evaluated, but also a need to generate a market for recycled fashion. "In order to facilitate the market uptake, we are working out the most important criteria together with fashion manufacturers. Because that's the only way a pair of pants can become a shirt one day," Bartl holds out the prospect.
Enzymes support recycling process
Many garments consist of two or more fiber materials. This has advantages for the functionality of the fabrics but complicates any recycling process at the end of the product's life time. Such fiber mixtures are not directly suitable for recycling, instead, elaborate separation processes are required.
Andreas Bartl, Emanuel Boschmeier and Wolfgang Ipsmiller are conducting research in particular into processes for recycling textile blends made of polyester and cotton, one of the most common material combinations on the market: "In order to be able to feed the polyester fibers into additional product cycles, the cotton fibers have to be removed from the textile. We succeed in doing this by using cellulases. These are enzymes that break down cellulose - the main component of cotton - into small molecules. In this way, cotton becomes glucose and can be reused in the chemical industry or as an integral feedstock in a circular bio-economy," Bartl explains. "The polyester fibers, on the other hand, are melted and processed into a granulate. If necessary, this granulate has to be post-treated to obtain a quality that is suitable for fiber production." Cellulases are already available on a large scale in industry, and re-granulation of PET is based on existing processes. The main task of the TU Wien is therefore to optimize the process in order to make it usable on a large scale overall.
A shift in the textile industry
"The next few months will be challenging for everyone involved in the textile processing chain," predicts Boschmeier, project assistant at SCIRT. This is because new legal and political framework conditions will be defined by 2025. Regardless of this, the industry is aware that the way in which textiles are handled will change significantly in the near future. In order to gain more knowledge and be prepared, results from the SCIRT project are urgently needed. The project partners are tackling the cause but not the symptoms: "It can't be our sole aim to develop recycling processes while, in parallel, more and more textiles are being put on the market and, above all, in ever shorter cycles," says Ipsmiller.
The SCIRT project is funded by Horizon 2020 for a period of three years. It is coordinated by the Flemish research institution VITO, which is based in the area of cleantech and sustainable development. A total of 18 partners from five countries are participating in SCIRT.
Dipl.-Ing. Emanuel Boschmeier
Institute for Process Engineering
Technische Universität Wien
Text: Sarah Link