In order to enhance the binding force between printing ink or vacuum aluminum plating layer and PET protective film surface, add adhesion fastness, coating method is also an effective way to improve the surface function of PET protective film.

Coating method is to coat the surface of the film with a layer of molecular solution, such as polyacrylate, modified polyester and other polymer solution. Between the longitudinal drawing machine and the horizontal drawing machine, equipped with an online coating machine, through the longitudinal stretching PET protective film, immediately online coating machine for polymer solution coating, and then into the horizontal drawing machine for horizontal stretching, in the horizontal drawing machine in the polymer solution of the solvent is dry after evaporation in the SURFACE of the PET film left a layer of molecular polymer.

The experimental results show that the surface wet tension of PET film can reach more than 58 mN/m after coated with modified polyester coating. And, coating method is a big advantage of the film surface wet tension will not be due to high temperature, high humidity climate conditions and attenuation, and water resistance, solvent resistance is good. The bonding force is strong after aluminizing the coating of coated film, and the delamination of aluminizing layer will not occur due to the touch of aqueous solution at high temperature.