High-grade food packaging such as thin-walled, resealable plastic containers or trays for convenience food are gaining in importance. Apart from polypropylene, PET is often used in these applications, as it is particularly suited due to its high transparency and good mechanical properties. The processing of PET poses a bit of a challenge, as a combination with water during processing can easily result in degradation reactions. An effective degassing in the extruder is therefore a must to reach good product quality.
The STARextruder series was designed principally for the extrusion of PET. The processing unit consists of three sections: a single screw zone for plastification of the material, a planetary roller section for degassing under high vacuum and an optimally dimensioned discharge zone. Thanks to the planetary roller degassing zone, highly efficient degassing of the melt is possible. Because of the functionality of the degassing section, the melt is rolled out in very thin layers and an extremely large surface is created. Both effects counteract the degradation of the materials and significantly contribute to optimal product quality.
STARextruders save energy by significantly reducing drying costs. The operator has a variety of benefits due to the design principle of the machines. Because STARextruders are based on standard single screw extruders, their handling is similar as well. Maintenance costs are lower thanks to higher wear resistance of the planetary roller section. A changeover from PET to PP or PS processing is also possible without a screw change. The machines’ proven concept enables the processing of PET bottle flakes with pre-conditioning. This process has recently been issued a letter of non-objection by the FDA (US Food and Drug Administration). The STARextruders’ available machine sizes of 90, 120 and 150 mm are perfectly suited for small and medium output ranges from 600-1,200 kg/h (1,300 to 2,600 lb/hr).