'Dryer-less' PET Sheet System

Processing Technologies International (PTi), recently took the wraps off its “dryer-less” twin-screw PET sheet extrusion system at its headquarters in Aurora, Ill. At a plant tour in conjunction with the 20th annual SPE Thermoforming Conference in Schaumburg, Ill., PTi unveiled its demo line, running an 85-mm, 52:1 L/D Luigi Bandera twin-screw extruder to process monolayer sheet from a blend of 40% virgin PET, 40% sheet skeleton regrind, and 20% post-consumer bottle scrap, all without predrying, at 1200 lb/hr. It also can run 100% post-consumer bottle scrap.

Marketed by PTi under the tradename of High-Vacuum Twin-Screw Extruder (HVTSE), the extruder features three vents: one is atmospheric and the other two use high vacuum to pull moisture and volatiles from the material. The 85-mm line is rated at 1700-2000 lb/hr for PET. Machine sizes of 105, 135 and 170 mm are also available. The system can also run PLA, PP, and PS without a screw change.

PTi and Bandera (based in Italy) announced their arrangement to bring HVTSE technology to North America early last year. Remarked PTi president Dana Hanson, “This isn’t a lab line, but a full-scale production plant.” Added Dennis Paradise, PTi sr. vp of sales and marketing, “This eliminates the uncertainties associated with a scale-up from a small lab line. It gives customers a proof-of-production result, and they potentially could produce samples at sufficient volumes for test marketing.”

PTi officials say one PET line has been installed (North America’s largest, with 5200 lb/hr capacity) and is operating at an undisclosed sheet production plant in North Carolina. Bandera reportedly has more than 80 systems running in Europe.

The PTi demo line included a five-component gravimetric loss-in-weight feeding system from Doteco (U.S. office in Dayton, Ohio), and a screen changer and melt-pump package from Kreyenborg Industries (Lawrenceville, Ga.), a three-layer EDI feedblock (Chippewa Falls, Wis.), and 60-in. die from Cloeren, Orange, Tex.