The stable state of the polymer chain of PVC Films For Labeling tends to be in a curled state. When the polymer is heated and melted in a high elastic state, the polymer chain is stretched and oriented under the action of an external force. And after the idle cooling reaches the glass transition temperature, the orientation state of the polymer chain is frozen. When the temperature rises again, the polymer chain tends to be in a stable state, curling occurs, and appears as shrinkage.
From the principle of shrinkage, there is no chemical change, so it is called "physical reduction." Blow molding to obtain PVC Shrink Printing Film is obtained by using the above principle and rapidly cooling after two inflation. PVC heat shrinkable film is a new type of packaging material popular in the world. It has good transparency, good toughness, impact resistance, corrosion resistance and low water vapor transmission. There is also an ideal shrinkage rate. When the film is subjected to a certain temperature, it shrinks automatically and tightly wraps the goods, thereby protecting the goods, and also functions as moisture proof, mildew proof, rust proof, pollution prevention, injury prevention and anti-theft function. Commodity storage stability, packaging process and equipment are relatively simple, it is easy to achieve automatic shrink packaging. PVC heat shrinkable film is used for the sale and transportation of various products. Its main function is to stabilize, cover and protect the product. The shrink film must have high puncture resistance, good shrinkage and certain shrinkage stress during the shrinkage process. The film can not produce holes. Since PVC heat shrinkable film is often used outdoors, it is necessary to add UV anti-UV agent.
It is used in pallet wrapping and other wrapping packaging, and it is widely used in foreign trade export, bottle making, paper making, hardware and electrical appliances, plastics, chemicals, building materials, agricultural products, food and other industries. The heat shrinkable film first appeared in Germany in the Second World War. It used PVDC and was used to package weapons after two-way stretching to prevent rust. Therefore, the heat shrinkable film was used in industrial packaging after industrial production from the beginning, and then the heat shrinkable film was used for food packaging.
If you have any other questions, feel free to contact PVC Shrink Sleeves Supplier.
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