The coupled coextrusion calendering process of multilayer thermoplastic sheets has been studied. The structure of the film has been observed, the density of chemical links at the interface and the adhesion between the coextruded layers have been measured. There are some controversial features about the influence of calendering parameters. Several models of increasing complexity are proposed to master the process and its influence on adhesion. A multilayer thermal model accounting for the crystallization kinetics of both polymers allows defining qualitatively the temperature field especially at the interface between the two layers. A multilayer thermo-mechanical model provides quantitative figures on the stress, shear, elongation and temperature fields in the coextruded film and especially at the interface. Relationships between these parameters, density of chemical links at the interface, crystalline structure of the sample and peeling forces are discussed.