Delicate laundering of textiles with application of 38 kHz ultrasonic waves

Ultrasonic cleaning in aqueous solutions was performed using various plain-woven fabrics soiled with oleic acid and/or carbon black as model oily and particulate contaminants. Detergency, which was evaluated from the change in the surface reflectance of the soiled fabrics due to cleaning, was promoted by applying ultrasound as the mechanical action for soil removal in the absence and the presence of anionic surfactant. Both soils were removed easily from the filament fabrics compared with the spun fabrics. Ultrasound, as mechanical action, was favorable for removing carbon black even in the absence of surfactant, whereas the addition of surfactant was effective for removing oleic acid without and with ultrasound. In most cases of soiled fabrics, the detergency obtained with ultrasonic washing for 1 min was comparable to that obtained with a drum-type washer, the Wascator (normal and gentle procedures). Heavy fabric damage was observed after washing with the Wascator, especially for the wool and silk fabrics, whereas there was little damage after ultrasonic washing for all fabrics. Conclusively, ultrasound can be effective in laundering for delicate textiles from the viewpoints of the processing time as well as detergency performance.