Surface Tension Effects on Ultrasonic Atomization and Implications for Roll Coating
High intensity ultrasonic vibration directed at a liquid surface can cause fine droplets to be thrown out of the surface, a phenomenon commonly referred to as ultrasonic atomization. In the present research ultrasonic atomization was shown to affect coating colours with solid mineral pigments. Coating colour misting, a runnability problem commonly reported in the paper coating industry, shows a strong similarity to the phenomenon of ultrasonic atomization. Therefore the phenomenon is suggested to be relevant to the coating industry.
Earlier research suggested effects of surface tension on the droplet size during the ultrasonic atomization process. Detailed studies on surface tension of the coating colour are included and the effects of surface tension on ultrasonic atomization of colloidal coating colours are discussed. Experimental work undertaken on the Monash pilot coating machine validates the effects of surface tension on the coating process.