High Intensity airborne ultrasound for debubbling liquid coating layers
Industrial coatings applied at high speed often contain bubbles from air entrapped during operation. Such bubbles will produce permanent surface defects after drying. Chemical additives are generally used to alleviate the problem, but they are difficult to dose and, if not properly handled, can create problems which may be even worse than the air retention.
High-intensity air-borne ultrasound may be an adequate contact-less method to break the bubbles. The majority of the existing studies about the application of high-intensity ultrasound in coating processes rely on the deaeration of the coating liquid previously to the coating process. Nevertheless, many of the bubbles within the coating layers are produced during the coating application. This work deals with a new process based on the direct application of air-borne ultrasound to break the bubbles which are semi-submerged within the coating layer.
Juan A. Gallego-Juárez, I. Gonzalez Gomez, G. Rodriguez Corral, E. Riera Franco de Sarabia, M. I. Garmendia Barrena, "Procedure and ultrasonic device for the elimination of occluded bubbles inpaint and varnish coating applied at high-speed. (Procedimiento y dispositivo ultrasónico para la eliminación de burbujas ocluidas en recubrimiento con pinturas y/o barnices aplicados a alta velocidad) Spanish Patent, nº200600619, 2006.
Main relevant publications
I. Gonzalez-Gomez, J. Rodriguez, I. Garmendia, J. A. Gallego-Juárez, "Application of high-intensity air-borne ultrasound for debbubling liquid films" Ultrasonics 44, Dec. 2006, Supplement 1, e529-e532