Application and Problems of Environment-friendly Water-based Inks (Chinese)

In fact, the viscosity and pH of the ink will also have a certain influence on the drying performance of the ink. For example, if the viscosity is too high, the drying speed of the ink will be reduced. If the pH is too low, the ink will be dried too quickly. Therefore, during the printing process, Should first adjust and control the viscosity and pH value of the water-based ink, and then add an appropriate amount of quick-drying agent or slow-drying agent to the ink according to the actual printing speed to adjust the drying speed of the water-based ink.
The fineness of the ink will not only have a certain influence on the coloring power and the color equal performance of the ink, but also affect the rheology of the ink. Ink particles are too thick, it is easy to cause the edge of the network hair, paste, and other ills; However, if the ink particles are too thin, the ink flow is too large, it will cause the network to expand, will inevitably affect the quality of printed matter.
2 affect the quality of water-based ink and should pay attention to a few issues a. Since ink is a pure water system, do not mix inks with alcoholic inks and solvent-based inks or add organic solvents to inks to avoid print quality problems.
b. The ink should be stored in the room at room temperature at 5 ~ 50 °C;
c. When using, stir the ink in the bucket with a stirring rod, measure the viscosity and pour into the ink tank. If the viscosity is too high or too low, it can be adjusted with thinner or thickener;
d. During the printing process, due to the volatilization of water, the viscosity of the ink will increase and the pH value will drop. The pH should be controlled between 8.5-9.5. If it exceeds this range, the pH stabilizer can be used to adjust the viscosity and pH value.
e. Under normal circumstances, the ink is very suitable for high-speed printing. If the drying speed is too fast or the printing effect is not good during low-speed printing, a certain proportion of slow drying agent can be added.
f. After printing, collect the remaining ink in the corresponding original bucket or tightly cover the ink tank for reuse. Beware of the consequent condensation, thickening or even drying of the surface of the ink due to evaporation of water;
g. The ink remaining on the printing setup after printing can be washed with fresh water before it is completely dried, and the ink that cannot be washed with fresh water can be cleaned with a cleaning agent.
2.1 Use of Ink Additives The printability of ink is affected by the printing conditions, the surface characteristics of the substrate, the ambient temperature and humidity, the length of the ink and other objective conditions, so when using ink, some additives are needed. Make fine adjustments to get the best print effect.
a. Color: used to darken color. The amount is 0 ~ 30%, more than 30% will make the content of the binder in the ink too low, resulting in the decline of its adhesion and wear resistance;
b. Evacuation agent: used to reduce the depth of color, the amount is not limited. The addition of a large amount of dissolving agent may cause the viscosity of the ink to rise slightly. At this time, a small amount of diluent may be added at the same time to adjust;
c. Thinner: used to reduce the viscosity of the ink. The use of less than 3% does not reduce the color depth of the ink and maintains the pH of the ink. Adding more diluent or diluting with tap water with high hardness will lead to the generation of bubbles, and defoaming agent can be added at the same time. Thinner should be added slowly while stirring to prevent excessive viscosity;
d. Slow drying agent: used to reduce the drying speed of ink, the amount of 0 ~ 10%;
e. Fast drying agent: used to accelerate the drying speed of ink, the amount of 0 ~ 3%;
f. Defoamer: Use 1000 to eliminate air bubbles, dosage is 1‰～2‰;
g. pH stabilizer: used to maintain the pH value of the ink, so that the pH of the ink is maintained at 8.5 ~ 9.5;
h. Thickener: used to increase the viscosity of ink, the amount of 0.5% to 1%.