The main methods for producing PVC film are calendaring, blow molding, and extrusion casting.
Calendaring: PVC resin is mixed with plasticizers, stabilizers, and other additives, then plasticized through a kneader or open mixer, and subsequently calendared into film using a multi-roll calendar. Films produced by this method have good quality and uniform thickness, making it suitable for producing high-quality, wide-width film products.
Blow Molding: PVC raw material is added to an extruder, heated and melted, then extruded through a ring die to form a tubular film blank, which is expanded into film using compressed air. This method has simple equipment and low investment, and can produce films of different widths, but the film thickness uniformity is slightly poorer.
Extrusion Casting: PVC material is plasticized in an extruder and then extruded through a flat die into a film, which is cooled and shaped by rollers. This method has high production efficiency and produces films with good transparency, making it suitable for producing relatively thin films.