The physical principle of heat shrinkable film

The heat shrinkable film is designed with the principle of stretching and orientation of polymer molecular chains, and is formed by the method of quenching and setting. The physical principle is: when the polymer is in a highly elastic state, it stretches the orientation, and then the polymer is quenched to below the glass transition temperature, the molecular orientation is frozen, and when the article is heated during packaging , Due to the stress relaxation caused by the thermal movement of the molecules, the molecules return to their original state and contract. This performance enables the heat shrinkable film to be smoothly affixed to beverage bottles of various shapes and to ensure smoothness and no wrinkles. Therefore, it is very important to test and control the heat shrinkage performance of PVC heat shrinkable film. PVC heat-shrinkable film is mainly designed by the principle of stretching and orientation of high-taken molecular chains. The physical principle is that when the ionomer is in a high elastic state, it is stretched and oriented. When the polymer is quenched to below the glass transition temperature, the molecular The orientation is frozen, and the items are packaged at this time. Due to the stress relaxation of molecular motion, the molecules will return to their original state and shrink. At present, the common heat shrinkable films on the market include PE shrinkable film, PVC shrinkable film, PP shrinkable film, POF co-extruded shrink film, etc. In the big family of heat shrinkable packaging film, POF three-layer co-extruded heat shrinkable film is a kind of A new generation of products that have gradually emerged and been accepted by people. Using a stretch film machine for product packaging can effectively reduce the cost of use. The use of stretch film is only about 15% of the original box packaging, about 35% of the PVC heat shrinkable film, and about 50% of the carton packaging. At the same time, the labor intensity of workers can be reduced, and the packaging speed and packaging quality can be improved. PVC heat shrinkable film is suitable for the packaging needs of products in various industries. It can be used for single or small collection packaging, or large tray packaging. It can be used for stationery, toys, textiles, paper products, beverages, medicine, Heat-shrink packaging for tongue-and-groove flooring, hardware and electrical appliances PVC heat shrinkable film is made of ethylene PVC resin mixed with more than ten kinds of auxiliary materials and then inflated twice. Its characteristics are good transparency, easy shrinkage, high strength, shrinkage rate can be adjusted freely according to user needs, and strong operability. PVC heat shrinkable film has good transparency, high shrinkage rate, between 40% and 60%, and its low cost, large tensile strength, large temperature shrinkage range, and low heat source requirements. The main processing heat source is Hot air, infrared or a combination of the two. Heat shrinkable film is a popular type of film in the market today. The reason is not only because of the characteristics of heat shrinkage, but also because of the wide range of applications of heat shrinkable film. Heat shrinkable film products are not only flexible, but also Strong tear resistance. Specifically, it has the following properties: 1. Unitization of heat shrinkable film: This is one of the characteristics of heat shrinkable film. With the help of the winding force and retractability of the heat shrinkable film, the product is compactly and fixedly bundled into a unit, so that the scattered small pieces become a whole. 2. The heat shrinkable film has compression fixation: the product is wrapped and packaged with the help of the retractive force of the heat shrinkable film to form a compact, space-saving unit, so that the product pallets are tightly wrapped together. It can effectively prevent the mutual dislocation and movement of the products during transportation, and the adjustable stretching force can make the hard products tightly adhere to and shrink the soft products. 3. Cost saving of heat shrinkable film: The use of heat shrinkable film for product packaging can effectively reduce the cost of use, and at the same time reduce labor intensity of workers, improve packaging efficiency and packaging grades. This is also a heat shrinkable film produced by heat shrinkable film manufacturers One of the highlights. Previous: POF shrink film application scope Next: PE heat shrink film composition standards