Familiarity with Common Additives in Water-based Ink

Posted on 04-17-2024 by

In water-based inks, common additives include pigments, pH stabilizers, drying retardants, defoamers, and diluents. It is important to be familiar with the characteristics and usage of these additives in printing.

1. Pigments are used to deepen colors, and their usage should generally be controlled within 0 to 30%. Exceeding 30% can result in a low binder content in the ink, leading to reduced adhesion and abrasion resistance.

2. pH stabilizers are used to adjust and control the pH of water-based inks, stabilizing it within 8.0 to 9.5 to ensure the printing performance of water-based inks. Additionally, they can adjust the viscosity of water-based inks and dilute them.

3. Drying retardants are used to reduce the drying rate of water-based inks, inhibiting and slowing down the drying speed to prevent ink from drying on the printing plate and reduce printing faults such as blocking and pasting. The usage of drying retardants should generally be controlled within 0 to 10% of the total ink amount. Excessive usage can result in incomplete drying of the ink, causing dirty prints or odors.

4. Water-based ink flushing agents are mainly used to reduce color depth, and there is no limit to their usage. However, adding a large amount of flushing agent may slightly increase the viscosity of the ink. In this case, a small amount of diluent can be added for adjustment.

5. Diluents are primarily used to reduce the viscosity of water-based inks, and their usage should be controlled within 3% to avoid reducing the color depth of the ink and maintain the pH value of the ink. Diluents should be slowly added while stirring to prevent the viscosity from becoming too low. If excessive diluent is added or hard tap water is used for dilution, it may result in the formation of bubbles, in which case defoamers should be added.

6. The main cause of foam problems in water-based ink usage is the use of water as a diluent. During emulsion polymerization, a certain amount of emulsifier must be used to greatly reduce the surface tension of the emulsion system.