Talking about the principle of heat shrinkable film, you must know!

Talking about the principle of heat shrinkable film, you must know! Hello everyone, I am the author. Today I will talk to you about shrink film. Let’s get to know it together. Heat shrinkable film is mainly used for labels, heat shrinkable packaging or stretch film. Polymer resins suitable for preparing heat shrinkable films mainly include PVC, PE, PS, PET, etc. After the film is preheated, it is stretched, cooled and shaped (as long as it is not heat-set) to obtain a heat shrinkable film. At the Tf close to the resin, the resin cast sheet is stretched in the transverse and longitudinal directions, and then quenched, so that the resin molecular chains are frozen in an oriented state, forming a heat shrinkable film. It is a process of entropy reduction from the raw material to the heat shrinkable film. The thermodynamic state of the heat shrinkable film is unstable. When the shrinkable film is heat treated, the oriented molecular chains will quickly return to the random coil state (curved state) , The film shrinks. This feature of heat shrinkable film can be used to prepare labels for special-shaped bottles. From the perspective of functional requirements, heat shrinkable sleeve labels have the characteristics of moisture-proof, anti-corrosion, impact-resistant, tear-resistant, odorless and non-toxic; they can play an anti-counterfeiting role; protect consumers from damage or rupture of containers accidental damage. The most important thing is that this label can be recycled, which has significant advantages in saving costs and protecting the environment. However, there are also many difficulties in the design of heat shrinkable sleeve labels. When producing heat shrinkable sleeve labels, the most widely used film material on the market is PVC heat shrinkable film. This kind of film has many advantages such as water resistance, fire resistance, high transparency, high gloss, high shrinkage rate, etc., but the material easily generates toxic gas when burned, which is not conducive to environmental protection. As a new material, OPS heat shrinkable film is a kind of skin packaging material that meets environmental protection requirements. It has many advantages such as high strength, high rigidity, good gloss, high shrinkage, and compliance with food hygiene standards. However, due to the current market There are not many companies that produce this film in Shanghai, and they cannot fully meet the market demand for this film. As for the ink, the quality of the ink directly affects the printing effect of the heat shrinkable sleeve label. Practice has proved that UV flexo printing ink is a very good choice, and its biggest advantage is that it can achieve higher color strength through curing and drying, which also brings great challenges to traditional gravure inks. If you want to know more about the latest industry information about shrink film, please log in to our official website and we will bring you more practical tips.