valssauskalvo

Valssauskalvo, or calendered film, is a type of polymer film produced by the calendering process, in which molten or semi-molten polymer is passed through a stack of rollers to achieve a uniform thickness and a controlled surface finish. The term is commonly used in Finnish plastics and packaging industries to describe films created primarily by calendering rather than by biaxial orientation.

Production and materials: Most valssauskalvo is based on polyolefins such as polyethylene (PE) or polypropylene (PP); other thermoplastics including PET, PVC, and specialty polymers may also be calendered. The process may start from an extruded sheet or a cast film, which is further processed in the calender stack where temperature, line speed, and roller gaps determine thickness (typically tens of micrometers to a few hundred micrometers) and surface gloss.

Properties and applications: Calendered films typically have a smooth surface, good dimensional stability, and moderate stiffness, with barrier properties that depend on the polymer used. They are widely employed as packaging films, laminating layers, release liners, protective films, and labeling substrates. Compared with cast or biaxially oriented films, valssauskalvo often offers lower production cost and simpler processing, but may exhibit lower stiffness, tear strength, and barrier performance.

See also: calendering, cast film, oriented film.