Influence of Pigment Particle Size on Anti-counterfeiting Effect of Structural Color Ink

In this study, the effect of pearlescent pigments and optically variable pigments with different particle sizes on the anti-counterfeiting effect of structural color anti-counterfeiting ink was discussed. The components of pigments, binders, solvents, and additives of structural color inks are initially picked out by experiments. The pearlescent pigments of different particle sizes (25, 40, 60, 100 μm) and optical variable pigments of different particle sizes (5, 10, 25 μm) were mixed to prepare structural color anti-counterfeiting ink samples Z1–Z5 via the controlled variable method. Screen printing was used to print the ink sample on a black matte cardboard substrate and observe the light change effect of the printed sample at different angles, so as to optimize the pigment formulation. The results show that when the particle size of the pearlescent and optically variable pigments were small, the structural color ink has a better printing effect, which has a three-time color change and good flashing effect. The structural color anti-counterfeiting ink prepared in this experiment has excellent anti-counterfeiting effect, facile production method, anti-precipitation performance, favorable stability, good gloss, strong adhesion, and environmentally friendly, which can meet higher anti-counterfeiting needs.