A New Scale-up / Scale-down Method for the Blown Film Extrusion

The development of innovative film products is a two-step process: New composite films or material recipes are first experimentally tested on a laboratory-scale blown film line, and then the results regarding process conditions and final film properties are transferred to a large-scale production plant. This procedure is generally known as scale-up. However, the transferability of results is not always ensured because of processing- and plant-specific restrictions. Thus, this paper presents a process-oriented scale-up / scale-down strategy (POSS), that should provide higher flexibility in practical use compared to existing scale-up strategies. To prove the feasibility of the process-oriented strategy, a series of experimental runs was carried out. An industrial production process on a high-capacity blown film line (> 750 kg/h) was selected as the starting point for a scale-down to a small-scale laboratory plant (scale-down factor of ten). Finally, mechanical properties of the film samples taken from the production process and the laboratory runs were measured and compared. The comparison showed that films with similar properties could be produced under process-oriented scale-down conditions.