PET sheet line: small twin-screw unit can replace large single screw

introduced to North America its latest development for PET sheet extrusion. For this latest generation in the Reitruder series, the geometry of the screws has been adapted by increasing the channel depth and redesigning the feed zone. These measures can improve the intake of PET flakes and regrind and enlarge the dosing volume of fillers. A significantly more efficient degassing system enables raw materials to be used even with a humidity of up to 0.5 %, says the firm, so that predrying can be minimized or completely eliminated.

Due to their efficiency and increased speed, small twin-screw Reitruder extruders can now replace large single-screw extruders, claims Reifenhäuser. According to Dieter Thewes, head of the extrusion division, “A Reitruder with 70-mm screw diameter and a capacity of up to 1200 kg/h can be used as an alternative to a single-screw extruder with 150-mm screw diameter and identical capacity.”

One clear target market is extrusion of thermoformable PET sheet, particularly post-consumer recyclate PET (PCR-PET) which can be heavily contaminated (e.g. PET with PE labels) and cannot be processed on extruders using conventional driers. Reifenhäuser’s twin-screw systems are capable of processing up to 2300 kg/hr of PET flakes. The company says it has sold a number of these sheet lines to customers in Europe and is now promoting this technology in the U.S.A. Some customers have already obtained FDA approval to extrude sheet from 100% bottle regrind for use in direct contact with food, adds the company. —[email protected]