A cheaper and more environmentally friendly process for dyeing fabric

Fabric has been dyed by the same wasteful method for over 100 years. This involves chemical agents being added to a dye bath and thrown away afterwards. A new process developed by EUREKA project E! 2625 EUROENVIRON ECDVAT (ElectroChemical Dyeing with Vat dyes) replaces environmentally damaging chemical reducing agents with electrons.

According to Prof. Dr. Thomas Bechtold of the University of Innsbruck’s Textiles Department, the new process can be more easily controlled. Using the conventional method, the amounts of chemicals and the bath temperature have to be calculated very carefully to get the dye level right. “With the new method, dyers can monitor the situation in the dye bath and can increase the electrochemical addition of chemicals to “steer” the process. Using electrons instead of chemicals means that the dye bath can be monitored and adjusted in real time,” explains Bechtold. “This is a big advantage and allows us to maintain the high quality of the dyed fabric,” he says.

The new process also has environmental benefits. Any chemicals released with ECDVAT are easily biodegradable and the partners are working towards greater water savings, expected to be as high as 85% of the volume used today in the dyeing process.

Dr. Wolfgang Schrott, Head of Technical Marketing at the German project partner, Dystar Textilfarben GmbH & Co. Deutschland KG, says that the project is a “big technical success,” but the equipment is still too expensive from a commercial point of view. “We need to concentrate on making the machinery cheaper,” he says.

“We expect savings in chemical costs and in fresh water and waste water treatment and to create better controlled processes with improved reliability, thus lowering the costs of unsatisfactory dyeings,” says Bechtold. “The development of cheaper and more efficient equipment on the basis of the results of ECDVAT will lower the costs further and make our high quality vat dyeing process even more attractive and competitive.”

Now the team’s strategy is to broaden the uses of the technology to bring down the cost and continue to make the process more profitable.

The partners expect other firms to become interested before too long as they are presenting their work at the “textile Olympics” – the four-yearly International Textile Machinery Association fair in Birmingham, UK, in October 2003.

“Being part of EUREKA helped in the formation of the group and brought extra funding,” explains Bechtold. “In Austria there is a special funding structure which increases financial support if a EUREKA project is formed.”