Scientists at the University of Leeds have developed a technique to dye polyester using 90 % less chemicals and 40 % less water.
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Fizzy water was the key to making polyester dye less damaging to the environment in a novel approach developed by an interdisciplinary team at SwitchDye, a University of Leeds spin-out firm.
More than half of all fiber produced worldwide is made of polyester, and production is growing annually. However, recycling polyester from garment to garment can be challenging, as it takes centuries to recycle. Approximately 20 % of the world's clean water contamination is attributed to the production of textiles, primarily due to the release of chemicals into wastewater during the dyeing process.
By lowering hazardous chemicals, water waste, and expenses, the company hopes to address these issues throughout the dyeing process. Researchers and co-founders Dr. Nathaniel Crompton, Dr. Harrison Oates, Prof. Richard Blackburn, and Prof. Chris Rayner believe that this might also make recycling polyester garments simpler and safer.
Professors Blackburn and Rayner created the concept, while Dr. Crompton developed the SwitchDye process as his PhD project in the Schools of Chemistry and Design.
SwitchDye could transform the textile industry by reducing its huge water use footprint and its pollution problem. Not many people know that even more toxic chemicals are used to turn brightly colored wastewater into transparent liquid. When released into freshwater, this is a secret killer that harms people, animals, and the environment. We can't solve this problem without the backing of industry, investors, and policymakers, so we’re excited to share SwitchDye publicly as we aim to scale up.
Dr. Nathaniel Crompton, Chief Executive Officer, SwitchDye
Collaboration
SwitchDye, developed via an ongoing partnership between Leeds' Schools of Design and Chemistry, makes it easier to insert and remove dyes from fibers by introducing a little amount of carbonated water into the dye bath. This causes the colors' distinct switching behavior within the polyester fibers.
SwitchDye, developed at the University's Nexus innovation community, also works on other synthetic fibers such as nylon and elastane and is equally as effective as commonly used dyes without sacrificing color. Importantly, it uses the same equipment that manufacturers currently have.
Polyester is highly durable, and straightforward to recycle, however the main issue is the color in the fabric. SwitchDye can be more easily removed from the fiber, making the clothes much more recyclable. Ultimately, SwitchDye helps to make the textile industry more circular and sustainable, in both the dyeing and recycling stages.
Dr. Harrison Oates, Chief Technology Officer, SwitchDye
Dr. Oates carried out a Ph.D. as part of the Priestley Center for Climate Futures.
Dr. Crompton and Dr. Oates met while working on their PhDs at the Wolfson CO2 Chemistry lab, a one-of-a-kind facility in the School of Chemistry for developing novel carbon dioxide-based processes. They rapidly became friends and subsequently business partners.
Industry Standards
The researchers thoroughly tested the dyes over several years using facilities at the University's School of Design and the Leeds Institute of Textiles and Colour (LITAC), ensuring that they meet or surpass industry requirements for color fastness.
Chris Rayner, Professor, Organic Chemistry, School of Chemistry, University of Leeds, added, “Richard and I have collaborated together for nearly 25 years on sustainability and green chemistry for coloration and textiles, combining our individual expertise. We are proud of how our multidisciplinary approach continues to pioneer innovative solutions to solve real-world problems.”
Richard Blackburn, Professor, Sustainable Materials, School of Design, University of Leeds added, “It’s been really exciting to see how the technology has developed, and we are especially grateful to The Clothworkers’ Foundation for funding our initial concept that was the subject of Nat's PhD, and to The Clothworkers’ Company for continuing to support the commercialization of the technology through LITAC.”
The Clothworkers' Foundation, The Dyers' Company, LITAC, The John Lewis Partnership Circular Future Fund in partnership with Hubbub, the Northern Triangle Talent Project (run by the University of Sheffield), and the UKRI Engineering and Physical Sciences Research Council (EPSRC) have all contributed to the project so far.
Jane Nicholson, Executive Director of Research at EPSRC, stated, “Sustainable approaches to polyester dyeing are paving the way to a cleaner, more circular textile industry. This startup company is an excellent example of how EPSRC investment in training, specifically in sustainable chemistry, is not only developing leaders of tomorrow but leading to new discoveries that fuel innovation.”
Over the next six months, the company aims to complete its first financing round, scale up dye production, and commence testing its dyeing technique on commercial-scale machines.