Contribution of Thermal Modelisation to Understand adhesion Mechanisms in Extrusion Coating: Case of Polypropylene on Aluminium

Abstract : A multilayered structure (polypropylene/grafted polypropylene/aluminium) manufactured by extrusion coating has been studied. The polypropylene film is extruded through a slit die, slightly stretched in air, coated on an aluminium foil in a laminator consisting of a chill roll and a flexible pressure roll, and finally cooled on successive chill rolls. Adhesive properties of polypropylene can be improved by grafting maleic anhydride on the polymer chain which may react with the aluminium surface. The reaction kinetic is more important for high temperature conditions.