Use of ultrasound in textile wet processing

The use of an ultrasound technique, developed at the Institute of Textiles & Clothing, Hong Kong Polytechnic University, offers numerous advantages during wet processing of textiles. The ultrasonic technique has been applied to different areas of wet processing including desizing, scouring and bleaching, washing and in dyeing, and finishing. The application of ultrasonics in the size box and steaming on the affinity of the sizing agent for cotton, polyester, and their blend warp yarns, gives a considerable potential for enhancing the affinity of the size for fibers. The use of degraded starch followed by ultrasonic desizing could lead to considerable energy savings as compared to conventional starch sizing and desizing. Scouring of wool with the ultrasonic technique in neutral or very light alkaline baths reduces fiber damage and enhances the rate of processing. The use of ultrasound in reactive dyeing of cellulosic fabrics can result in energy savings, less water consumption, increased depth of color, and better process conditions. It can also increase wool coloration and makes it possible to reduce dyeing time and save on textile auxiliary products. Application to dyeing seems to be the most advantageous of all the textile wet processes, followed by finishing and preparation processes.