Reasons for poor wetting of ink paint film and the effect of wetting leveling agent

During the process of printing with ink, the wetting effect of the coating and ink is related to the solid content and surface tension of the dampening solution. The lower the surface tension of the dampening solution, the better the leveling performance. Generally, water-based coatings and inks have high surface tension of pure water, and it is necessary to use wetting agents to reduce the surface tension of pure water in order to achieve good leveling effect on the wetting plate.

The surface tension of coatings and ink pastes decreases rapidly with the increase of substance concentration. If the substance concentration continues to increase, the surface tension remains almost unchanged for book printing. Therefore, adding a wetting leveling agent to the solution should be appropriate and not too much.

When the surface tension of the ink coating is lower than that of the dampening solution, under the action of diffusion pressure, the ink infiltrates in the direction of the dampening solution, causing the printing dot to expand and dirty the blank area.

On the contrary, if the surface tension of the dampening solution is lower than that of the ink, the printing factory will infiltrate the dampening solution in the direction of the ink under the action of diffusion pressure, causing the dots in the printed product to disappear. Only when the surface tension of the dampening solution is equal to that of the ink, the diffusion pressure at the interface is zero, and the dampening solution and ink maintain relative balance at the interface without wetting each other, can the printing effect be more ideal.