In order to obtain the good adhesion of the ink to the substrate, the bottle must be polarized so that the surface tension of the bottle is no less than 3.8 × 10-2n / M (generally speaking, the most basic condition for the ink to have good adhesion to the substrate is that the surface tension of the substrate reaches at least 50dyn / cm).
The method of polarizing the bottle is mainly flame treatment. The principle of flame treatment is to decontaminate the plastic surface through high temperature and melt the film surface, so as to improve the surface energy of the plastic bottle and improve the adhesion of its surface to ink. In short, before printing, we must ensure that the surface of the substrate is clean and effective polarization treatment. If the surface treatment of the bottle is not complete, the adhesion will be affected.
Flame treatment:
The flame processor is composed of conveyor belt, conical inserting column, flame nozzle and gas tank. When in use, the plastic bottle is placed on the conical inserting column, and the conveyor belt moves forward at a uniform speed. Before reaching the flame nozzle, the conical inserting column starts to rotate and drives the bottle to rotate. The blue flame ablates the surface of the plastic bottle, so as to improve the surface energy of the plastic bottle and increase the binding force with the ink.
