Schematic of the ultrasonic atomisation
spraying system

Ultrasonic application of clay nanoparticles to biodegradable films could enhance their barrier properties, according to spray technology company Sono-Tek, based in New York, USA.

The company says that the technique prolongs the shelf-life of food and pharmaceuticals and offers the packaging industry more accurate and economical treatment.

‘The capability of nanoclay particles to create efficient barrier protection against water and oxygen molecules is well known, but commercialising this phenomenon using conventional coating techniques such as air pressure spraying, or printing press technologies, lacks sufficient uniformity, as well as being costly,’ explains Joseph Reimer, President of Sono-Tek.

'Nanoparticles have a tendency to agglomerate while being dispensed, resulting in an uneven layer thickness of the final coating. Our technique imparts vibrations into the liquid suspension and provides an agglomerate-free, uniform coating.’

The system features an ultrasonic atomising nozzle, which uses high frequency sound waves to produce a soft, low velocity spray, typically three to five inches per second.

'The unpressurised spray reduces the amount of overspray since the drops settle on the substrate rather than bouncing off, reducing waste,’ says Reimer.

A pilot scale production line is being built to test the feasibility of the continuous process for industrial applications.

Further information:

Sono-Tek