The key to the production of protective plastic film for metal is to select the appropriate coating method and coater according to the protective film coating performance and the specific requirements of the protective film, and determine various process parameters of the coating machine operation. In the packaging industry, there is a special protective material called protective plastic film for metal, which is attached to various metal plates, plastic plates, glass and other surfaces to protect the fine surface of articles during transportation, processing, storage and use. This requires excellent performance pressure sensitive adhesive / acrylic / PU glue.
The viscosity and other rheological properties of the adhesive used in the protective plastic film for metal are the most important properties affecting the coating behavior of the protective plastic film for metal. According to the dependence of the viscosity on the shear speed, the fluid can be distinguished into Newtonian fluid, expanded body and pseudoplastic body. According to the change of viscosity shear time, the fluid is divided into Newtonian fluid, thixotropic body and rheological body.
The rheological properties of the adhesive deviate from the Newtonian fluid, and the more easily the quality problems occur in the coating operation, especially when the adhesive exhibits the properties of the expanded body, because its viscosity will follow the coating speed during the coating process. Increase and increase rapidly.
In the process of coating the protective plastic film for metal, it is necessary to use a large mechanical force to spread the adhesive. Therefore, the faster the coating speed, the more difficult to obtain a uniform coating, and often the force is too large to break the substrate or even damage. The scraper, when the adhesive exhibits thixotropic properties, the leveling property of the adhesive layer is poor when applied, and thus it is difficult to obtain a smooth and smooth adhesive layer.