PET heat shrinkable film is a new type of heat shrinkable packaging material. Because of its easy recycling, non-toxic, tasteless, good mechanical properties, especially in line with environmental protection, PET has become an ideal substitute for PVC heat shrinkable film in developed countries. However, ordinary polyester is a crystalline polymer, and the thermal shrinkage of ordinary PET film can only be less than 30% after special process treatment. In order to obtain polyester film with higher thermal shrinkage, it must be modified. That is to say, in order to prepare high thermal shrinkage polyester film, it is necessary to modify the common polyester, namely polyethylene terephthalate. * * * The maximum thermal shrinkage of poly-modified PET film can reach more than 70%. Thermal shrinkable polyester film is characterized by being stable at room temperature, shrinking when heated (above the glass transition temperature), and more than 70% of thermal shrinkage occurs in one direction.

The advantages of heat-shrinkable polyester film packaging are: ① rain-proof, moisture-proof and mildew-proof. ② Tight packaging and good anti-scattering. ③ No resilience, with certain anti-counterfeiting function. (4) Close-fitting and transparent, reflecting the product image. Heat shrinkable polyester film is often used in convenience food, beverage market, electronic appliances and metal products, especially shrink label is its main application field. Because with the rapid development of PET beverage bottles, such as cola, sprite, all kinds of fruit juice and other beverage bottles need PET heat shrinkable film to match with them for heat sealing labels. They are polyester, environmentally friendly materials and easy to recycle. In addition to being used as shrink labels, heat-shrinkable polyester films have also been used in the outer packaging of daily commodities in recent years. Because it can not only protect the packaged goods from impact, rain, moisture and rust, but also make the products win users with beautifully printed outer packaging, and also show the good image of the manufacturers. At present, more and more packaging manufacturers use printed PET heat shrinkable film to replace the traditional transparent film. Because printing shrink film can improve the appearance grade of products, is conducive to product advertising, and can make trademark brands leave a deep impression on consumers.