Comparison of pvc shrink film and pof heat shrink film

PVC heat shrinkable film is a good film packaging material. It has the following advantages: (1) Good transparency, allows customers to directly see the packaged goods, and facilitates customers to choose goods (2) Close to the shape of the goods , Can be applied to the packaging of various shapes of goods, with a wide range of packaging contents (3) excellent anti-theft and dust resistance (4) a variety of goods can be packed in a heat shrinkable packaging bag to prevent individual small goods from being lost, It is also convenient for customers to carry. (5) Different resins and formulas can be used to produce heat-shrinkable films with different mechanical strength and functions. It can be used for inner packaging with lower strength and lower product weight, or for higher strength requirements. Transport packaging (outer packaging) for machinery products used in containers and building materials. The production method of heat-shrinkable film is to use extrusion blown film or extrusion casting method to produce thick cylindrical film or flat thick film after resin particles enter the extruder. For crystalline polymers, in order to prevent and reduce crystallization Therefore, the cooling water quenching method should be used to cool the thick film, because the crystallized thick film cannot be stretched in two directions or one direction. Stretching will destroy the crystal and reduce the mechanical strength and performance of the film. The produced thick film is reheated to the resin's T g ~ T f temperature, that is, mechanically stretched longitudinally or transversely in a high elastic state between the glass transition temperature and the melting temperature, and then cooled to become a heat shrinkable film. For amorphous polymers, such as PVC, it can be stretched directly from the molten state to a highly elastic state, and then rolled into a heat-shrinkable film without quenching and then heating. The T g, T f and stretch orientation temperature of various resins are listed in Table 1.　　 Label: pof heat shrinkable film