Plants for the Processing of Biodegradable Material
In addition to classic engineering plastics such as PE, PP and PA, Coperion is also specialized in the design of compounding systems for biodegradable products. The manufacturing method for biodegradable products evolved from the processing of thermoplastic starch. Starch is not thermoplastic and has to be transformed before it can be alloyed with other biodegradable products such as polylactic acid (PLA), polycaprolacton (PCL), polyvinylalcohol (PVA) or synthetic polyesters.
Coperion’s technical engineers configure modular compounding systems that exactly meet the requirements of the customer. Our experts define the right machine size of the twin screw extruder, i.e. the screw diameter for a given throughput quantity must be chosen and the structure and length of the process section including the screw geometry must be determined. In addition, gravimetric feeders, raw material feeders and intermediate storage for the end product are selected. Vacuum pumps for drawing off steam and other undesirable volatile components from the polymer melt must be configured. The design of the granulation depends on the water sensitivity of the biodegradable products. Both underwater and water ring and air pelletizers can be used. Alternatively the plastic can be cooled in a water bath and cut by a strand pelletizer. Transfer of the end product and its intermediate storage as well as the handling of the raw material are planned and executed by Coperion.
Producing biodegradable products is also possible using direct extrusion. Direct extrusion or in-line compounding enables the production of semi-finished products such as films, sheets, tubes or profiles in one process step – intermediate pelletizing is omitted completely. Coperion is considered a specialist for the production of direct extrusion plants.