How is heat shrinkable film produced?

The products packaged by heat-shrinkable film are not only beautiful and generous, but also save packaging costs. They can also be packaged for promotional purposes, and they are also sealed, dust-proof, moisture-proof and anti-theft. The heat shrinkable film is so powerful, how is it produced? Let me explain to you the knowledge of heat shrinkable film production: 　　 It is blow molding using the process of rapid cooling and shaping. The shrinkage principle is the memory effect of polymer, that is, the film is above the glass transition temperature T g and the melting point T m When stretched under the temperature conditions, the disorderly curled molecular segments are oriented in the stretching direction and arranged in an orderly manner. At this time, the temperature drops rapidly, and the molecular segment orientation structure and internal stress are 'frozen'. When the polymer is heated again to the temperature at which it was stretched, the molecular chain segments will de-orientate, stress relaxation will occur, and the disordered coiled form will be restored. Macroscopically, it will show thermal shrinkage. Heat-shrinkable film materials can not only reduce packaging production costs, transportation costs, and reduce packaging volume, but also because of their higher transparency, good printing performance, and increased product shelf life, they can quickly grab the attention of consumers in a competitive market. , Cater to consumer needs. Previous: A collection of advantages of POF heat shrinkable bags