Current physical cavitation processes can reduce BOPP film density to 0.5 to 0.6 g/cc.
Current physical cavitation processes can reduce BOPP film density to 0.5 to 0.6 g/cc. A new developmental process called Triaxcell reportedly can reach densities down to 0.3 and perhaps 0.2 g/cc. Developed by Conenor Ltd., a technology development and licensing company in Tampere, Finland, the process is aimed at films for frozen foods and adhesive labels. The process starts by reducing the die temperature to the crystallization point of PP (300 to 320 F) to create micro-fractures in the melt curtain. Then the film is MD oriented to elongate the fractures. The web then goes into a chamber where pressurized air is forced into the cavities. This is followed by TD orientation using a circular stretcher of Conenor’s own design, which has a continuous-belt gripping mechanism that spreads the load. Finally, the web passes over tempering rolls and gets edge-trimmed before winding. Conenor has a lab line for product development and is looking for a machinery partner to develop full-scale equipment. Tel: +358 (40) 753-4605 • www.conenor.com