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How to control the drying time of water-based ink

The water-based ink can be mixed with water before drying. Once the ink is solidified, it is no longer soluble in water and ink. Therefore, the water-based ink must be fully stirred before use to keep the ink composition uniform. So how should we control the drying time of water-based inks?

Water-based ink

Do not let the ink dry on the anilox roller when printing, so as not to block the ink hole. Impeding the quantitative transmission of ink causes unstable printing. In the printing process, the flexographic plate should always be wetted by the ink to avoid clogging the text pattern on the printing plate after the ink dries. In addition, it is found that when the viscosity of the water-based ink is slightly larger, it is not appropriate to add water casually, so as not to affect the stability of the ink, and an appropriate amount of stabilizer can be added to adjust.

In order to obtain a reasonable drying speed for flexographic water-based inks, there are the following suggestions during use:

1. Properly increase the pH value of the water-based ink to reduce the drying speed of the printing process without affecting the drying speed. The pH value is generally controlled at 8.5-9.5. If it dries too fast, add a stabilizer to control the pH value above 9, but not exceed 9.5, otherwise the ink properties will change.

2. Without affecting the printing speed, try to make the drying speed of the water-based ink slower, which can be adjusted by adding a slow drying agent. The amount of slow drying agent to be added for different inks is different, generally not more than 5%. After adding the slow drying agent, the ink will thicken and the pH will decrease. Therefore, when adding the slow-drying agent, water and stabilizer should be added to control the viscosity and pH of the ink.

3. When printing thin paper products, reducing the drying speed of the water-based ink can reduce the warpage of the paper. This usually requires the addition of slow-drying agents or retarders to adjust. This is because after the water-based ink is printed, the water and alcohol in the ink volatilize, making the tight edges of the paper loose and warping. The effect of slowing down the drying agent is to prevent the ink from drying out instantaneously and to reduce warpage.

4. Enhance the convection speed of the air in the oven, which can obviously speed up the drying speed of the printed matter. Because the water-based ink contains a large amount of water and alcohol, enhanced convection can be reduced, and the relative humidity in the oven accelerates the evaporation of the solvent.

5. The addition of slow-drying agent can solve the scratches of the printed matter and the surface of the varnish. Ink drying too fast will cause the ink to dry on the surface of the printing material before entering the penetration stage, resulting in insufficient adhesion, and the ink layer is easy to fall off. In the case of overprinting or glazing, the latter color printing plate will stick the ink of the previous color. This can also be adjusted by changing the color sequence or reducing the ink viscosity.

6. Adding slow-drying agent and speeding up can reduce the blocking phenomenon. If the printing speed is too slow, the ink will spread on the printing plate, causing dot adhesion. However, if the ink dries too fast, the ink will not be transferred sufficiently, causing ink to accumulate around the dots, causing blockage.

7. The paper guides generate heat and can also speed up the drying of printed materials. When the amount of ink used for printed products is large, if the drying capacity of the printing machine is limited, the speed is not fast every time the machine is turned on. After a period of time, the speed has a certain room for improvement. This is why the paper guide roller heats up. The ink is not easy to stick to the surface of the paper guide roller after it heats up. Before starting, the independent drying device is opened in advance. The device can be turned off immediately after the device is turned on, so that the device can accumulate the maximum heat in the shortest time. The vehicle speed can be increased quickly.

8. When the amount of ink used in the printed product is large, try to use high color density ink and anilox roller with a higher line number, which is conducive to the drying of the printed product and can also reduce the water mark phenomenon.

9. The ink viscosity required for higher printing speed is lower, which is conducive to the transfer of ink.

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