Swiss scientists have developed a process with substances other than PFAS that can be used to produce environment-friendly water-repellent textile fibres. Initial analyses show: The "good" fibres repel water more effectively and dry faster than those of conventional products.
- They used so-called highly cross-linked siloxanes, which create silicone-like layers and—unlike fluorine-containing PFAS—are harmless.
- In initial laboratory analyses, textiles made from the new fibres with an environment-friendly coating are already performing slightly better than conventional PFAS-coated fabrics.
- The properties of the fluorine-free coating come into their own after the textiles have been washed several times: While the performance of conventional PFAS coatings in stretchy textiles declines considerably after repeated wash cycles, the fluorine-free fibres retain their water-repellent properties.
THE RESEARCH: The co-friendly fibres have been developed at the Swiss Federal Laboratories for Materials Testing and Research, better known by the shorter EMPA.
THE PFAS ISSUE: If swimming trunks are to retain their shape after swimming and to dry quickly, they must combine two properties: They must be elastic and must not soak up water. Such a water-repellent effect can be achieved by treating the textiles with chemicals that give the elastic garment so-called hydrophobic properties.
- In the 1970s, new synthetic fluorine compounds began to be used for this purpose—compounds that seemed to offer countless application possibilities, but later turned out to be highly problematic.
- This is because these fluorocarbon compounds, PFAS for short, accumulate in the environment and are harmful to our health.
THE PLASMA CLOUDS: EMPA's plasma coating facilities range from handy table-top models to room-filling devices. For the coating of textile fibres, the siloxanes are atomised and activated in a reactive gas.
- They thereby retain their functional properties and enclose the textile fibres in a water-repellent coating that is only 30 nanometers thin. Fibres coated this way can then be processed into water-repellent textiles of all kinds, for example garments or technical textiles such as upholstery fabrics.
- The advantage over wet-chemical processes: Even with complex structured textiles, the seamless distribution of the hydrophobic substances is guaranteed right into all turns of the intertwined fibres. This is crucial, because even a tiny wettable spot would be enough for water to penetrate into the depths of a pair of swimming trunks, preventing the garment from drying quickly.
INTEREST FROM INDUSTRY: The Swiss textile companies Lothos KLG, beag Bäumlin & Ernst AG and AG Cilander are already on board when it comes to developing environmentally friendly fluorine-free textiles.
