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The ideal point of ink viscosity in high-speed rotogravure printing (2)

Update time : 2020-10-29

Source : Zhejiang Deguang Machinery Co.,Ltd

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The ideal point of ink viscosity in high-speed rotogravure printing (2)

gravure printing knowledge

As mentioned above, in high-speed rotogravure printing, when the ink viscosity is too high, resin pigments and other substances have poor fluidity, fail to be evenly dispersed, and are easy to pile up. Under the relatively high-speed movement of the doctor blade and the plate cylinder, the doctor blade and the plate The tube is easily damaged, and linear dirt is likely to occur. At the same time, because the resin is also in a state of supersaturation, a large amount of resin agglomerates together, and the affinity of the resin to the roller, under the pressure of the doctor blade, the resin will stick to the roller tightly (the pigment is entrained in the resin). In this way, flake stains appear. Generally speaking, the ink printing viscosity is small, and the dirty plate phenomenon is not easy to occur.

However, if the printing viscosity of the ink is too small, it means that the content of the organic solvent in the ink is high, and the resin, pigment and other components are relatively small, so that it cannot form a smooth film when drying, and the printed matter will become white and dull. Light, lack of gloss. Therefore, if the printed product needs to have better gloss, it is generally necessary to consider using a larger printing ink viscosity (13~19S, Zahn No. 3 cup), that is, relatively more resin and pigment components to meet the requirements of the printed product. need.

At the same time, when the ink is printed on the plastic and becomes an ink film after drying, the wrapped pigment can be firmly attached to the plastic surface, and the resin is the main material that firmly adheres to the plastic. Therefore, the bonding firmness of the pigment is also related to the printing viscosity of the ink. This shows that the ratio of the resin and the pigment in the ink cannot be too large or too small, but should be within the normal range, so that the bonding firmness of the pigment is great.

Under the normal environmental humidity, the printing viscosity of the ink is above 16S (Zahn No. 3 Cup), and static electricity generally does not occur. The printing viscosity of ink is below 16S (Zahn No. 3 Cup). As the viscosity decreases, electrostatic phenomena such as beard-like, streak-like, edge repelling, ink flying, poor transfer, and extremely irregular paint stains will follow. Happened and worsened.

In view of the above-mentioned reasons, the industry believes that the ideal state of ink printing viscosity is generally found between 11~17S (Zahn No. 3 Cup). If static electricity occurs within this range, based on the principle of mutual consideration, generally do not increase the viscosity of ink printing to eliminate static electricity, but maintain normal environmental humidity, change the structure of thinner components, install static elimination brushes, and use static electricity. Eliminate static electricity by means of preventive agent. Only in this way can we improve efficiency and yield while ensuring quality, laying the necessary foundation for printing companies to obtain profits.

Zhejiang Deguang provides you with professional gravure printing knowledge and various types of printing machines. We are an experienced printing company. If you want to know more details about ink printing viscosity, you can contact us.

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