Printability of the hottest aluminum foil ink

2022-08-15
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Printability of aluminum foil ink

the printability of ink comes from its internal structure and its inherent physical and chemical properties. However, in the process of application, it must be verified by the whole stroke of the printing machine, the overall drying process on the substrate and the printing quality. Of course, the printability of ink is not isolated, but reflected in the coordination of printing press, printing materials and other conditions

the suitability of ink in the printing machine journey is not discussed in this paper, and the focus is on aluminum. The experts in the industry pre meeting introduced this new product to the industry about the fixation of ink on the foil paper at the moment of inking (initial drying of ink), because it involves two key issues: printing stickiness and drying function

generally speaking, penetration is the basis for the fixation of ink on the substrate; The fixation speed is the condition for the drying of the ink layer in the middle stage; The medium drying time is the key to the quality of the ink layer conjunctiva

1. Penetration is the foundation of fixation. The binder in resin based medium and high-grade offset printing inks is mainly composed of resin, dry vegetable oil and ink oil. Among them, the resin dissolved in dry vegetable oil belongs to high viscosity phase; Ink oil is a low viscosity phase. According to the introduction, it is composed of miscible (not really soluble) state and high viscosity. Because the function of ink oil is only to dilute and reduce the viscosity of the precursor phase, so that the ink can be used in the printing press. Therefore, when the ink completes its mission based on the study of 46 kinds of minerals in the world (at the moment when the ink is printed on the substrate), it must leave the ink system immediately, and the faster it leaves, the better. This is the prerequisite for ink fixation penetration

2. The fixation speed is the condition for the drying of the ink layer in the middle stage. The fixing speed is mainly determined by the instantaneous penetration of the ink oil miscible in the ink system on the substrate. The greater the instantaneous penetration, the faster the separation of high and low viscosity in the ink. The concentration of high viscosity components of resin and dry vegetable oil can increase sharply. The instantaneous physical changes make the ink layer form a gelatinous state and fix on the substrate. Whether the high and low phases can be completely separated determines not only the fixation speed of the inking layer, but also the drying time of the inking layer in the medium term

3. The medium drying time is the key to the quality of the ink layer conjunctiva. The so-called medium-term drying time refers to the intermediate stage of the ink layer from fixation to conjunctiva, which lasts about 3 hours. Its phenomenon is similar to the physical state of conjunctiva, and it feels smooth when lightly rubbed, but it cannot be rubbed with force. With such a degree of medium-term drying, it is known that the solvent has completely escaped from the system, and the dry vegetable oil has undergone oxygen absorption polymerization, gradually changing to gelled solid state, and finally achieving complete drying of the conjunctiva. This is the key to benign conjunctiva

4. Obviously, to penetrate, you must have a substrate with absorption performance. However, the aluminum foil on the surface of aluminum foil paper does not have this condition

for aluminum foil without absorption, whether offset printing ink or special ink is used, liquid solvent still remains after inking. Such an ink layer is not only the main factor for the dirty printing, but also the root cause of poor dryness. Therefore, in order to overcome the difficulty of dirty and dry prints, we must change the way of ink penetration and improve the inherent conditions

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