(Source: HS Münchberg)
From 2025, used clothing and other textiles will be collected separately throughout Europe to facilitate reuse and high-quality recycling. Activities for the development of new fibers, chemical auxiliaries and colorants which are more suitable for recycling are on the way.
What will be the biggest challenges for the global textile industry for the recycling of textiles?
The usage of fiber blends is a big challenge for the recycling of textiles. For recycling, identification and separation of every single fiber component is necessary. Here we must develop fast, automatic identification methods and sustainable separation processes.
Technical textiles are often composite materials (for example coated tarpaulins), where the challenge is to separate the fiber from the coating.
Could you please explain the different recycling technologies to us?
Mainly, 2 methods are used for the recycling of textiles – mechanical and chemical recycling.
For mechanical recycling textile waste or food packaging is collected and shredded. The small pieces are used to produce new fibers, for example, making recycled PET fibers from PET bottles.
The other method is to collect textile or plastic waste and perform a depolymerization process, which disassembles the waste into its constituent monomers. These monomers are used to produce new polymers, e.g. making PA fibers made from depolymerized tire rubber. This is the chemical recycling.
Are new fibers made from these regenerated polymers, or can these polymers also be used as raw materials for other products?
In addition to the textile production chain, a lot of other polymer waste could be the raw material for textile finishing products, such as silicone softening agents based on silicone polymer waste.
We have already heard about several recycling fibers. Are there already auxiliaries and dyestuffs made from recycled raw materials on the market?
At the moment recycled PET, recycled PA (mainly PA 6) and Lyocell fibers made from recycled cotton are available. Recycled PET is produced by mechanical and chemical recycling. For recycled PA, in my opinion chemical recycling is predominant. Lyocell fibers are made by chemical recycling.
I only know silicone softener based on recycled silicone. Reclaiming of indigo from denim washing companies is a big issue, but here one problem is the large distance between denim dyeing mills and denim washing companies. At the moment, the other problem is the price of virgin indigo in comparison to the higher price of reclaimed indigo.
What could a sustainable textile and apparel industry look like in the future?
To create a sustainable textile and apparel industry is a big challenge. In my opinion, we need resource efficient production processes (e.g. usage of green electricity instead of fossil fuels for drying processes) in combination with bio-based or recycled fibers and textile auxiliaries. How can these goals be achieved? Should individual stakeholders work more closely together? And what role can the consumer play?
Both textile (bio)chemists and mechanical engineers are necessary to speed up the transition towards a resource efficient and sustainable future.
In my opinion, the consumer is the key player for a sustainable textile production. Because textile recycling is impossible without participation of the consumer. Consumers should accept higher prices for sustainable textiles made from recycled fibers or made with auxiliaries based on recycled polymers.
The interview was conducted by Mechthild Maas, editor of TextileTechnology, with Prof. Michael Rauch, Head of Master program Sustainable Textiles at Hochschule Hof, Campus Münchberg/Germany and International Federation of Associations of Textile Chemists and Colourists (IFATCC).