Soil removal from polyester fabric by laundering with frequency-modulated ultrasound.

The effectiveness of ultrasound in washing textiles was investigated using polyester woven fabrics soiled with model contaminants such as oleic acid/Sudan III mixture and carbon black. The soiled and original fabrics were washed together in aqueous solutions with shaking or frequency-modulated ultrasound. The detergency and the soil redeposition were evaluated from the change in the surface reflectance of the soiled and the original fabrics due to the washing. The results were strongly dependent on the type of mechanical action. Ultrasound removed the contaminants in a short time and at low bath ratios as compared with shaking. In addition, the ultrasound caused little damage to the fabric during washing. The detergency was much larger for the ultrasonic washing than for shake washing in aqueous solutions containing alkali, surfactants, and commercial detergent. However, uneven cleaning and soil redeposition were frequently observed during ultrasonic washing. This was the only observed limitation to this approach of textile washing.