Biaxially oriented polypropylene film (BOPP) is generally multi-layer co extruded film, which is made of polypropylene particles through co extrusion to form a sheet, and then stretched in both vertical and horizontal directions. Due to the tensile molecular orientation, the film has good physical stability, mechanical strength, air tightness, high transparency and gloss, tenacity and wear resistance. It is the most widely used printing film at present, with a thickness of 18 ~ 40 μ M ^, the most widely used is 19 μ m.
The main disadvantage of biaxially oriented polypropylene film is poor heat sealing, so it is generally used as the outer film of composite film. For example, after compounding with polyethylene film, moisture resistance, transparency, strength, stiffness and printability are ideal, which is suitable for holding dry food. The surface adhesion of polypropylene film is very poor due to its poor surface adhesion and non crystallinity before printing.
