At present, water-based inks are a new type of ink that is low in toxicity or practically non-toxic, non-irritating, non-flammable, and non-explosive. It is most suitable for gravure printing of food packaging, and has become a future development trend in terms of green environmental protection requirements. Water-based inks are mainly processed by composite grinding of water-soluble resins, organic pigments, solvents and related additives. In the process of gravure printing, there are many places to pay attention to water-based gravure inks. This paper analyzes water-based gravure printing. The function of the ink and the issues to be concerned with, in order to communicate with the industry.
What is water-based ink?
Water-based inks are mainly processed by composite grinding of water-soluble resins, organic pigments, solvents and related additives. As a key component of water-based inks, water-soluble resins must be used as a solution directly in the production process. Therefore, the water solubility of water-soluble resins is an extremely important property, and the molecular weight cannot be too large. Otherwise, water solubility will be difficult. During the heat curing process, a cross-linking reaction between the reactive groups in the resin system or the reactive groups of the external crosslinking agent forms an insoluble and insoluble network structure, thereby providing excellent black film properties. The solvent used is mainly pure water and a small amount of alcohol. In order to increase the solubility of the water-soluble resin in water, an alkaline neutralizing agent is added to the system to convert a water-soluble resin having a hydrophilic group such as a carboxyl group into an ammonium salt which is completely soluble in water. When drying, water volatilizes from the surface of the wet film, the overall volume of the black film shrinks, and the resin (ammonium salt) pigment gradually concentrates; after more water is volatilized, the resin (ammonium salt) is de-amined by heat, and finally the resin is dehydrated and deaminated. Forming a black film that is insoluble in water. Therefore, the drying process of the aqueous ink is a process mainly consisting of volatilization and solidification reaction.
Water based gravure ink function
1 Compared with water-soluble ink, the water-based ink has good dot reproducibility, large difference in dot transfer property, slow drying and low viscosity. Therefore, the ink in the cell is scraped by the doctor blade and transferred to the ink. The viscosity does not rise, and the transfer of high-profile parts is good. Therefore, a plate making process and an electric carving curve are required for the water-based ink in the plate making process.
2 The volatile organic solvent content is reduced, and the organic volatiles are discharged less, thereby reducing the air pollution and improving the working environment of the field operators.
3 The flammability of the ink and the electrostatic concentration are greatly reduced, which ensures the safety of the production site operation and fire protection.
The main problem to be concerned with the use of water-based gravure inks
1 plate cylinder. According to the characteristics of water-based inks, a set of plate-making processes and parameters such as electric separation, engraving, electroplating and polishing are formulated, so that the water-based ink can achieve the printing reduction effect on the original printing and even exceed the solvent-based ink.
2 printing substrate. Water-based inks should have good printing properties such as fluidity, transferability, leveling, and abrasion resistance to meet the high-quality printing standards for flexible packaging.
3 printing conditions. The ratio of the diluent, the viscosity of the ink during printing, the pH value, the oven temperature, and the post-press processing.
4 printing environment. Since the water-based ink and the diluent are water-based, the working environment of the printing should be kept ventilated and dry.
Due to the low volatility and high transfer rate of the water-based ink compared to the solvent-based ink, the non-patterned ink of the printing plate is not easy to be scraped, and the fogging phenomenon is easy to occur, and the surface finish of the printing plate and the adjustment of the blade are relatively strict. Claim. Therefore, the printing process must be carried out in strict accordance with the process flow.
Article source address: http://
Men Beard Care,Beard Care Grooming,Man Face Cleanser,Beard Dye Cream
Guangzhou Yilong Cosmetics Co., Ltd. , https://www.skinmelao.com