Ink pigments for water-based inks

Pigments give the ink color characteristics meet the color requirements of printing. General organic pigments inorganic pigments can be used for water-based inks. Since the resins of water-based inks are mostly alkali-soluble, when choosing pigments, it is necessary to use alkali-resistant pigments. However, the distribution density of pigments in water ink is much greater than that of solvent-based inks, the surface tension polarity of water are greatly different solvents, making pigment dispersion more difficult, which directly affects the stability, viscosity pH of inks.

Adding surfactant can increase the affinity of resin water the affinity of pigment water-soluble binder, so as to solve the problem of ink stability. The viscosity pH of ink need precise control. When the pH value is higher than 9.5, the alkalinity is too strong, the viscosity of the ink will decrease, the drying speed will slow down, the water resistance will be poor; when the pH value is lower than 8, the alkalinity is too weak, the viscosity of the ink will increase dry Speeding up will cause defects such as dirty version, paste version, foaming. When using pigments in the printing process, high-grade pigments with bright colors, low viscosity, stable system among domestic pigments should be selected to make water-based inks.