The viscosity and other rheological properties of the protective film adhesive are the most important properties that affect the coating behavior of the protective film. According to the dependence of the viscosity on the shear rate, the fluid can be distinguished by Newtonian fluid, swelling body and pseudoplastic body, The change of the shear time, the fluid and the Newtonian fluid, the thixotropic body and the rheology, the rheological properties of the adhesive deviate from the Newton fluid, the more likely it is to have various quality problems in the coating operation, especially when When the adhesive exhibits the properties of the expanded body, its viscosity increases rapidly with the increase of the coating speed during the coating process, and it is necessary to use a larger mechanical force to expand the adhesive. Therefore, the faster the coating speed is, Of the coating, but also often due to excessive force and pull off the substrate, or even damage the scraper, when the adhesive showed thixotropic properties, the coating when the leveling layer is very poor, and therefore difficult to get smooth Adhesive layer.