1. Non-polar polymer, PE protective film has small surface free energy and low surface wet tension, generally about 30 dynes / cm. In theory, if the surface tension of the object is less than 33 dynes / cm, ordinary ink or adhesives cannot be firmly attached, so the surface must be treated;
2. Polyesters (PET, PBT, PEN, PETG) are polar polymers with a high surface free energy and a surface wet tension of more than 40 dynes / cm. However, for high-speed color printing or to increase the bonding force between the vacuum aluminum layer and the surface of the BOPET film, the surface treatment of the BOPET film is also required to further increase the surface wet tension;
3. Transfer of aluminized layer will occur during aluminizing, and transfer of an adhesive layer will occur during the application of glue. The main measure to prevent the corona on the reverse side of the film is to adjust the pressure of the rubber pressure roller in front of the corona treatment roller. The pressure on both ends of the pressure roller must be consistent and the pressure should be appropriate.