Water-based Ink Printing Conditions

The printing suitability of water-based inks is affected by the objective conditions such as printing conditions, surface characteristics of the substrate, ambient temperature and humidity, and storage time. Therefore, some additives are needed to finely adjust the ink to obtain the best printing effect. . The commonly used additives in water-based inks are color materials, pH stabilizers, slow-drying agents, defoamers, thinners, etc., and the characteristics and methods of use of the additives should be familiar with the printing.

1) The colorant is used to deepen the color, and its dosage should generally be controlled at 0 to 30%. If it exceeds 30%, the content of the binder in the ink will be too low, resulting in a decrease in adhesion and wear resistance.

2) The pH stabilizer is used to adjust and control the pH of the aqueous ink to stabilize it at 8.0 to 9.5 to ensure the printing state of the aqueous ink. At the same time, it can also adjust the viscosity of the aqueous ink and dilute the ink.

3) The slow drying agent is used to reduce the drying degree of the ink. The slow drying agent can suppress and slow the drying speed of the water-based ink, prevent the ink from drying on the printing plate, and reduce the occurrence of printing failures such as blocking and paste. The amount of slow-drying agent should generally be controlled to 0~10% of the total ink. If the amount is too much, the ink will not dry thoroughly, and the printed matter will be dirty or odor.

4) Aqueous ink thinner is mainly used to reduce the depth of color, and the amount is not limited. However, the addition of a large amount of thinner may cause a slight increase in the viscosity of the ink, and a small amount of diluent may be added at the same time for adjustment.

5) The dilution is mainly used to reduce the viscosity of the ink. The dosage should be controlled within 3%, so as not to reduce the color depth of the ink, and keep the pH value of the ink unchanged. The diluent should be added slowly while stirring to prevent the viscosity from being too low. If more diluent is added or diluted with tap water with high hardness, bubbles will be generated, and an antifoaming agent should be added.

6) The main reason for the foaming problem in the use of water-based inks is that water is used as a diluent. When the emulsion is polymerized, a certain amount of emulsifier must be used to greatly reduce the surface tension of the emulsion system.