How does flexo uv ink for paper adhere firmly to the paper and not fall off easily?
Release Time : 2025-06-19
Flexo uv ink for paper can be firmly attached to the surface of paper, first of all due to its unique formula design. This ink is added with a special binder, which is like a strong "glue" to build a tight connection bridge between the ink and the paper. The binder is usually composed of polymer resins, which have good affinity and can attract the cellulose molecules on the surface of the paper. When the ink is applied to the paper, the resin molecules will quickly penetrate into the pores of the paper fibers, like countless tiny tentacles tightly grasping the internal structure of the paper, thereby significantly enhancing the bonding force between the ink and the paper.
The UV curing process is a key link to ensure the firm adhesion of the ink. Different from the natural drying method of traditional inks, flexo uv ink for paper will be exposed to ultraviolet rays immediately after printing. Under the action of ultraviolet rays, the photoinitiator in the ink is activated, which in turn triggers a series of complex chemical reactions. The original liquid ink components will undergo a polymerization reaction in a very short time, and instantly transform from a flowing liquid to a solid film. This curing process is not only fast, but also the solid film layer formed has a dense structure, tightly wrapping the paper fibers, making the ink and paper a tightly combined whole that is difficult to separate.
The treatment process of paper surface also plays an important role in ink adhesion. In order to improve the adhesion of ink, paper is usually pretreated. For example, corona treatment technology is used to increase the roughness and polarity of the paper surface by high-voltage discharge. The surface of the treated paper becomes more "rough", just like adding countless tiny "hooks", providing more attachment points for the ink. At the same time, the enhanced polarity of the paper surface makes the molecular force between the ink and the paper greater, further improving the adhesion effect of the ink. In addition, some papers are pre-coated with a thin layer of primer, which can fill the tiny pores on the surface of the paper, improve the surface flatness, and enhance the compatibility with the ink, creating better conditions for ink adhesion.
The rheological properties of the ink also affect its adhesion effect on the paper. Flexo uv ink for paper has moderate viscosity and thixotropy. Moderate viscosity ensures that the ink can be smoothly transferred from the printing plate to the paper during the printing process, and will not flow or diffuse due to low viscosity, ensuring the clarity and accuracy of the pattern. Good thixotropy makes the viscosity of the ink drop rapidly when it is subjected to printing pressure, which facilitates the ink to be evenly coated on the paper surface; when the printing pressure disappears, the viscosity of the ink can be quickly restored to prevent the ink from excessively penetrating or accumulating on the paper surface. This perfect rheological property enables the ink to form a uniform and tight ink layer on the paper surface, thereby enhancing the adhesion.
The control of environmental factors should not be ignored. In the printing process, the stability of temperature and humidity is crucial for the adhesion of ink. The appropriate temperature can ensure that the components in the ink maintain good fluidity, which is convenient for printing transfer and curing; the appropriate humidity can prevent the paper from becoming brittle due to excessive dryness or deforming due to excessive moisture, which affects the adhesion of the ink. In addition, the accuracy and stability of the printing equipment will also indirectly affect the ink adhesion effect. Accurate printing pressure control, a stable ink supply system, and good overprinting accuracy all help the ink to be evenly and accurately transferred to the paper, thus laying the foundation for firm adhesion.
Finally, flexo uv ink for paper will undergo a lot of testing and optimization during the research and development and production process. By simulating different printing conditions and usage environments, the ink formula, curing process, etc. are repeatedly adjusted and improved. For different types of paper, we will also develop special ink products to ensure the best matching effect between ink and paper. It is this comprehensive technical consideration and meticulous process control that enables Flexo UV ink for paper to adhere firmly to the paper, and even when it experiences external forces such as friction and bending, it still maintains excellent resistance to falling off, providing reliable guarantee for high-quality printing.