When using screen printing, all inks are called screen printing inks. Volatile drying inks are the most used inks in screen printing. The components of the ink film are mainly polymer substances. After printing, the solvent volatilizes, and the polymer substances form the ink film. This volatilization drying process is reversible, that is, the dried ink film can be redissolved with a solvent.
1. Properly increase the pH value of the ink to reduce the drying speed of the screen printing process without affecting the drying speed. The pH value is generally controlled at 8.5 to 9.5. If the drying is too fast, the pH value should be controlled above 9 by adding a stabilizer, but it should not exceed 9.5, otherwise the properties of the ink will change. The surface tension of the ink is lower, the screen version is more likely to be blocked, and the drying will become slower.
2. Adding slow-drying agent and speed-up can reduce the blocking phenomenon. If the screen printing speed is too slow, the ink will spread on the printing plate, causing the dots to stick. However, if the ink dries too fast, the ink will not be fully transferred, resulting in the accumulation of ink around the dots and blocking the plate.
3. In the case of not affecting the screen printing speed, try to let the ink dry slowly during the screen printing process. This can be adjusted with a slow drying agent. The amount of slow-drying agent added to the inks of different manufacturers is different, generally not more than 5%. The ink will thicken and the pH will decrease after adding the slow-drying agent. Therefore, when adding the slow drying agent, water and stabilizer should be added to control the ink viscosity and pH value.
4. Adding slow-drying agent can solve the scratches of screen prints and the surface stickiness of varnish plates. If the ink dries too fast, the ink will dry and solidify on the surface of the printing material before it enters the penetration stage, resulting in insufficient adhesion and the ink layer will fall off easily. This can also be adjusted by changing the color sequence or lowering the ink viscosity.
5. The paper guide roller heats up, which can also speed up the drying speed of the screen prints. When we use a large amount of ink for screen printing products, if the drying capacity of the screen printing machine is limited, the speed is not fast when it is first turned on, and there is a certain room for improvement after a period of time. This is the paper guide Roller heats up. After the paper guide roller is heated, the ink will not easily stick to its surface. Before starting the machine, turn on the independent drying device in advance. When the machine is turned on, the suction device can be turned off first, so that the equipment can accumulate the maximum heat in the shortest time. Speed can be increased quickly.
