Waterless dyeing process

The Yeh Group, which produces both warp and weft knitted fabrics, says it will be the first textile manufacturer to implement a new waterless dyeing process developed by DyeCoo Textile Systems of the Netherlands which is currently being readied for commercial introduction in the fourth quarter of this year. The company says it has exclusive rights to the process and is branding fabrics produced using it as DryDye fabrics. 

2 Supercritical fluid CO / supercritical fluid dyeing technology 

Supercritical fluid refers to the phase of a substance with both temperature and pressure higher than the critical point (the point where liquid and gaseous phases of a substance become indistinguishable). This phase of a substance enjoys many advantages and can replace water in the dyeing process. The supercritical fluid normally used is carbon dioxide (CO ), as the critical temperature and pressure are easier to achieve than that of other substances. Moreover, carbon dioxide is also non-flammable without residues, so it is suitable for industrial use. 

Supercritical fluid CO has become a mainstay in extraction processes in the food industry (decaffeination, extraction of hops) and apparel dry cleaning, where it has proven to be the best, gentlest, most thorough cleaning method 

Elimination of the water process and chemicals is a real and significant breakthrough for the textile dyeing industry. This new process utilizes supercritical fiuid carbon dioxide (COj) for dyeing textile-materials. It is a completely waterless dyeing process using only nominal amounts of CO, nearly all of which is recycled. DryDye fabrics dyed with this unique waterless process will have the same dye qualities and durability as cmrent, conventionally dyed fabrics, a spokesperson for the Yeh Group said. 

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The Yeh Group, which claims to be an innovative, environmentally responsible producer of quality knit fabrics and garments, supplies to premium brands in sports and intimate apparel markets. By pioneering and implementing this new waterless dyeing process, the company says it will eliminate the use of millions of litres of fresh water in dyeing fabrics using the new process. 

In the area of preparation and dyeing, there are waterless processes based on supercritical carbon dioxide fluid (SCF) technology. These use no water at all, and drying is simply a matter of allowing the carbon dioxide to evaporate, which happens immediately upon releasing the supercritical pressure. Since there is no water or pollution associated with the process and the CO2 evaporates without any applied heat, energy is saved [5]. Intensive research is underway to commercialize this process. 

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