METHOD FOR MANUFACTURING A FILM COMPRISING CAVITIES WITH DETERMINATION OF STRETCH, DENSITY, THICKNESS AND/OR POROSITY PROFILES OF THE FILM

摘要

The invention relates to a method for manufacturing a film (F1) comprising cavities and formed using a polymer in which a cavitation agent is dispersed, the method comprising a step of extruding polymer within an extrusion die equipped with actuators (Act) for adjusting the thickness of the extruded film and a step of stretching (Str 1) the film, and establishing a film mapping function using mass per unit area profiles of the film before and after the stretching step, a stretch profile of the stretched film using the mapping function and the transverse mass per unit area profiles, and a characteristic transverse profile of the film using the stretch profile and a transverse mass concentration profile of the cavitation agent within the stretched film which allows the distribution of the cavities within the film to be taken into account, a method in which the adjustment actuators are controlled according to the characteristic transverse profile.