The performance of the ink mainly depends on the resin emulsion; for instance, the viscosity, adhesion, gloss, drying, and printing adaptability of the ink are mainly determined by the resin. Water-based inks use water-based acrylic copolymer resins, as these resins have significant advantages over alkyd resins, epoxy resins, and polyurethane resins in terms of gloss, weather resistance, heat resistance, water resistance, chemical resistance, and pollution resistance, enabling them to exhibit excellent performance whether in direct dispersion or in the synthesis of high molecular emulsions.

When promoting water-based inks, due to the limitations of printing equipment and drying equipment, ink manufacturers often add a certain amount of alcohols (mainly ethanol) to the ink during formulation or printing plants during printing to increase the drying speed of the ink. This requires the resins used in the ink formula to have certain alcohol resistance.

Water-based inks are prone to plate blocking during intaglio printing, significantly reducing the printing adaptability of the ink. The main factor affecting ink plate blocking is the re-dissolution (i.e., re-solubility, the ability of the ink remaining in the ink well after the ink well is filled with ink to be dissolved again) of the ink. When the re-dissolution of the ink is weak, the ink remaining in the bottom of the mesh cavity is difficult to be dissolved again by the ink in the ink well, thus easily causing plate blocking, and resulting in poor reproduction effect in the shallow mesh area. In flexographic printing, due to the fixed perimeter of the mesh roller on the equipment, the perimeter of the plate roller is variable and changes according to the product's repeated length, transferring the ink on the mesh roller to the printing surface of the plate. If the re-dissolution of the ink is good, the ink on the mesh roller can be replenished in time, and the ink transferred to the printing surface is very full, without ghosting. Conversely, when the re-dissolution of the ink is poor, the ink transferred to the printing surface varies, with strong color concentration in the areas with more ink and weak color concentration in the areas with less ink, resulting in ghosting. Therefore, the re-dissolution of the ink is an important indicator of ink quality and has a significant impact on the printing and composite quality of soft packaging composite materials. The core technology of water-based ink adhesion to films is to select appropriate water-based emulsions. The emulsion is the main film-forming resin of the ink, with fewer hydrophilic functional groups, and the ink film has good resistance, but its re-dissolution is poor.

Therefore, the good re-dissolution of the emulsion-type resin is a key element in solving plate blocking and ghosting during the printing process of water-based inks. At the same time, the water resistance and wet rubbing resistance of the ink film are the key points that the printing ink needs to pay attention to. The water resistance and re-dissolution of water-based inks are a pair of contradictions. When improving the re-dissolution of the ink, the problem that its water resistance and wet rubbing resistance are poor follows. Therefore, it is necessary to balance the contradiction between water resistance and re-dissolution.

Sinograce Chemical Materials is committed to becoming a leading supplier of water-based materials and a provider and service provider of comprehensive solutions!