Analyze the causes and solutions of slow drying of printing ink

If the ink can be fixed well, it will dry from the inside out. In this case, although the ink surface can resist static pressure after solidification, the ink layer can not resist friction. Ordinary ink for offset printing mainly depends on chemical reaction to dry, and the oxidation and polymerization of ink turpentine are promoted by desiccant and are important components of ink.

If the ink is not dry enough to resist the pressure of the next printing color, the paper cannot print the second color. Worst of all, if the ink needs to be dried for a long time, the medium containing turpentine will excessively penetrate into the paper, and the ink film lacks the ability to bind pigments, which may lead to white deterioration. Operators should know that this kind of trouble is very complicated, and it is based on unbalanced factors such as ink, paper and printing conditions.

Remedial measures

1. Temperature
As drying is one of the chemical reactions, air temperature can affect its drying speed. It is ideal to control the temperature of paper or printing room from 60℉v to 0℉ if it is under abnormal conditions.
2. Desiccant
If the amount of desiccant in the ink is not enough, pay attention to its characteristics and amount, and add some desiccant to the ink. But it is not recommended to add too much desiccant.
3.Control the wetting moisture
Too much wetting water causes this trouble.
4. Moisture of paper
Too much moisture in the paper will slow down the drying speed. In this case, it is best to strengthen the desiccant.
5. The PH value of the sink
Too much acidity (low PH) in wetting water will reduce the activity of desiccant. The suitable range of PH is from 5.0 to 6.0. At a minimum, the PH should be maintained above 4.5.
6. PH value of paper
For the same reason mentioned above, it is very dangerous for the PH value of paper to be too low. When the PH of the paper is too low, such as less than 4.5 in non-coated paper and less than 6.0 in coated paper, it is necessary to use a strong desiccant or a larger amount of ordinary desiccant than usual.