We all know that stretch film is mainly used in the packaging industry. Regardless of the shape and size of the item. The membrane can play a good role under its special characteristics and advantages. But, when some users are transporting items, they find that the items are scattered. Find out why, it turns out that the film itself of the packaged item has changed. The tightness of the film was reduced a lot, which caused the situation of packaging Guo Song. So what factors affect its tightness?

1. Polyesters (PET, PBT, PEN, PETG) are polar polymers. The surface free energy is high, and the surface wet tension is above 40 dynes / cm. But for high-speed color printing or to increase the bonding force between the vacuum aluminized layer and the BOPET film surface. Surface treatment of BOPET film is also required. To further increase its surface wet tension;

2. For non-polar polymers, the stretched film has small surface free energy and low surface wet tension. Generally about 30 dynes / cm. Theoretically, if the surface tension of the object is lower than 33 dynes / cm, ordinary ink or adhesive cannot be firmly attached. Thus, its surface must be treated;

3. The aluminized layer transfer will occur during aluminizing, and the glue layer transfer will occur during the glue application. The main measure to prevent the corona on the reverse side of the film is to adjust the pressure of the rubber pressure roller before the corona treatment roller. The pressure at both ends of the pressure roller should be consistent and the pressure should be appropriate.

In fact, there is also the problem of excessive looseness during the production of stretched film. We can know through the answers of professionals. The tightness of the film surface will depend on the molecular structure of the film material itself. The free energy of the film surface determines whether the film has good elasticity. Thus, all aspects of the performance of the film are related to each other. So no matter during the production of the film or when it is used, the relevant operations must be carried out according to the regulations. More precautions should also be understood.