Evaluation of 9-layer film blowing process by using variational principles

Abstract

In this work, coextrusion experiments utilizing an industrial 9-layer Brampton Engineering coextrusion film blowing line for LDPE/LDPE/tie/PA6/EVOH/ PA6//tie/LDPE/LDPE film production has been performed under different processing conditions (different air cooling intensity and mass flow rate) in order to evaluate variational principles based modeling approach for the multi-layer film blowing process. It has been revealed that the variational principle based model can describe the bubble shape, temperature profile and predict internal bubble pressure reasonably well for all applied processing conditions even if the multi-layer film has been viewed as the static elastic membrane characterized only by one material parameter - bubble compliance J, which was not allowed to vary along the multi-layer bubble.