Polypropylene Pop Quiz

Ross Wooldridge, Super Film of America

Q: How can converters compensate for polypropylene's tendency to relax or 'snap back' under press tension controls, and elongate during lamination?

A: When printing on polypropylene, converters should set a minimum tension to keep the web in register. Once register is established, repeat length can be established. Converters can compare plate or cylinder circumference to the repeat length to calculate and compensate for snap-back.