The surface tension of the film is directly related to the surface free energy of the film, which is determined by the molecular structure of the film itself. Therefore, there are many factors affecting the surface tension of the wound film. The main contents are as follows:
1. For non-polar polymers, the surface free energy and surface wet tension of the winding film are relatively low, generally around 30dyn/cm. Theoretically speaking, if the surface tension of the object is less than 33dyn/cm, ordinary ink or adhesive will not adhere firmly, so it is necessary to carry out surface treatment;
2.Polyester (PET, PBT, PEN, PETG) is a polar polymer with high surface free energy and surface wet tension in excess of 40 dyne/cm. However, in order to increase the adhesion between the vacuum aluminized layer and the BOPET film surface, surface treatment is required to further improve the surface wet tension of BOPET film.
3. The aluminum layer will transfer in the electroplating process, and it will also transfer in the adhesive layer. The main measure to prevent tension film from backcorona is to adjust the pressure of rubber roller before corona treatment roller. The pressure at both ends of the roller must be consistent and appropriate.
4.The purpose of the test was to prevent corona from entering the intima when the dynamic tension was less than 0.05 mm. Thank you very much for your attention to the price of winding film.