The authors have recently introduced Ovonic Clearcoat, an ECD process using a silica barrier coating technology for plastic films, for use in packaging applications. The 120Å thick coating on 0.5mil thick PET film, deposited in pilot roll-to-roll equipment provides excellent water vapor barrier performance of less than 1g/m²/24 hrs. and excellent oxygen barrier performance of less than 1ml/m²/24 hrs. Additionally, the barrier coating is transparent, colorless, flexible, microwavable and retortable.
ECD's process utilizes proprietary low-pressure microwave plasma-enhanced chemical vapor deposition (PECVD) process to deposit high quality SiO_x type coatings at high deposition rates.
A patented deposition process, incorporating a serpentine pass line, facilitates high speed roll-to-roll vacuum deposition. The microwave-induced plasma deposition area is enclosed by the moving web. Consequently, the deposition area is large and the gas utilization factor is high. The combination of high deposition rate and efficient utilization of actives species leads to a high-speed process. The deposition takes place on the non-cooled surface of plastic film which travels at high speeds. Use of the microwave plasma process provides highly energetic depositing species which form denser and higher quality coatings, even at the low substrate temperature required for plastic films.
The authors have applied the ECD process to a number of polymer films now on the market. The barrier properties of these polymers coated by the process are found to be superior.