Production process of POF heat shrinkable film

The production process of POF heat shrinkable film is different from the traditional blow molding process. Due to the poor tensile properties of PP melt, the traditional blow molding process cannot be used, and a double-bubble process, also known internationally as the Prati process, is used. The specific process is as follows:

Raw material preparation: The main raw materials such as linear low-density polyethylene (LLDPE) and polypropylene copolymers (TPP, PPC) and necessary functional additives such as lubricants, anti-blocking agents, and antistatic agents are mixed in a certain proportion.

Extrusion plasticization: The mixed raw materials are fed into different extruders and melted and plasticized by heating.

Co-extrusion die forming: The molten raw materials pass through a specially designed co-extrusion die to form a primary film.

Quenching and shaping: After the primary film is formed, it is immediately quenched to quickly shape it.

Secondary inflation and stretching: The film, after quenching and shaping, is heated and subjected to secondary inflation and stretching to stretch it in both the longitudinal and transverse directions, thus obtaining better performance.

Winding and packaging: After secondary inflation and stretching, the film reaches the specified thickness and width, and then it is wound and packaged into a finished product.