Modelling of film casting manufacturing process longitudinal and transverse stretching

Film casting is a widely used manufacturing process used to shape polymers into high quality films for package or other industrial and commercial purposes. The relevant steps of the manufacturing process are the longitudinal and transverse stretching, in which the material assumes the required dimensions and mechanical properties. This paper deals with the modelling of longitudinal and transverse stretching of the film casting process of isotattic polypropylene. These models are based on the suitable analogy (confirmed by experimental data) between the behavior of the polypropylene and some metals and on the remarkable directionality of the mechanical properties of the final product. Modelling leads to evaluation of the profiles of pressure and speed and of normal and tangential stresses.