Three factors that affect print dryness

First, the impact of environmental temperature and humidity

1. Influence of ambient temperature

When the temperature rises, the speed of the molecules increases, the intramolecular energy increases, and more peroxides are easily generated with the activated genes, thereby accelerating the polymerization of oil molecules. Therefore, as the temperature rises, the oxidative polymerization of the ink will increase, thereby accelerating the drying of the ink.

The drying process of the ink ink film is an exothermic reaction, and the heat released when the print sheet is dried also accelerates the drying of the print. The effect of temperature on the speed of the drying of the blot is obvious. The temperature of the environment increases, the ink dries quickly, and vice versa. For example, in the hot summer weather, bright fast-drying inks can dry quickly without adding dry oil, but in the cold winter season, dry oil is needed.

2. Influence of environmental humidity

During the offset printing process, we need to moisten the plate layout with water. Water is a polar molecule, and oil is a non-polar molecule. Because wetting the plate with water, ink emulsification occurs and the ink emulsion is controlled between 10 and 30%. In the range, the concentration and evaporation rates of water are closely related to the drying of the blot. Because water molecules are very polar substances, the presence of water can hinder the oxidation polymerization of oil molecules to form a film, which will affect the drying speed of the imprinting. The level of the environmental humidity will play a role in the evaporation rate of the water. Increased ambient humidity, oxygen in the air will also reduce the activity, reducing the ink to the suction of oxygen, while the ink ink film emulsified layer of moisture to make the ink film softened, so that the ink drying speed slows down. Therefore, in the offset printing process, we must control the balance of ink and water, and use less water as much as possible to avoid ink emulsification. The amount of water in the ink is very close to the drying of the print.

Second, the impact of ink auxiliary materials

Transparent dilutants, white oils, detackifiers, etc. all have the property of inhibiting the drying of the ink and slow drying of the print. The main components of diluting agent, weili oil, white ink, white oil and the like are the presence of aluminum oxide in the link material and aluminum hydroxide. It is insoluble in water. Since aluminum hydroxide is easily dissociated by water, the degree of emulsification of the ink is increased during printing, so that the print is dried more slowly. Wiley oil is generally used as a dilute agent for multi-color overprint inks for common products. Dilute ink colors have no effect basically, but the brightness is generally low and drying is slow. White oil is a white translucent emulsion, use it to dilute the ink can reduce the viscosity of the ink, color uniformity, white oil has no dryness, pine contains water, so that the ink accelerates the emulsification, water intake after the ink layer gradually Evaporation removes the oxidative polymerization process of the ink and can severely affect the drying rate of the print.

In the offset printing process, in order to change the printability of the ink, or to reduce the viscosity of the ink, non-dried auxiliary materials such as a detackifier are often added, and the gloss and fluidity of the ink color are not substantially affected. However, it cannot be used in excessive amounts. Because of its non-dry and penetrating substances, it is easy to cause the disadvantages of slow drying of the imprint, and the content in the ink is less than about 5%.

In general, if the ink needs to be diluted and de-bonded, the amount of driers should be increased accordingly in the ink. Such as: red, white dry oil.

Third, the impact of the water bucket solution

The water tank solution can not be separated from the acidic substances, such as: phosphoric acid, citric acid, etc. First, the gravure plate needs to supplement the inorganic salt layer lost during the printing process. Phosphoric acid and other acidic substances have the function of cleaning the ink dirty, and the acidity will make The drying of the ink is destroyed. The stronger the acidity of the hopper solution, the slower the drying time of the ink. Therefore, to control the PH value of the hopper solution, when the hopper solution is formulated, the wetting powder instructions are used.