Viscosity is a property that prevents fluid flow. It is a measure of the ability of the interaction between fluid molecules to hinder the relative movement of its molecules, that is, the resistance of fluid flow. Viscosity control is the most important control index in the application of ink, because it directly affects the transfer performance of ink and the quality . Low viscosity and fast ink transfer in printing will cause disadvantages such as light color, large dot expansion, deformation of , uneven ink transfer; high viscosity and slow ink transfer will affect the transfer performance of the anilox roller, ink color , etc. Unevenness, but sometimes the color is not printed deeply, and it is easy to cause problems such as dirty and pasted plates.
Ink viscosity is usually related to the following factors:
(1) Related to the linking material: For inks using the same pigment, the greater the viscosity of the greater the viscosity of the ink made . The linking material mentioned here refers to the ink component including the solvent. All liquid media.
(2) The relationship with the amount of pigments and fillers: For the same kind of binder, the more the amount of pigments and fillers, the greater the viscosity
(3) It is related to the dispersion of pigments and fillers: the better the pigments and fillers are dispersed in the binder , the smaller the viscosity the higher the viscosity
(4) It is related to the particles of pigments and fillers: for the same kind of binder, if the amount of pigments and fillers in the ink is the same, the larger the particles of pigments and fillers, the higher the viscosity of the ink. Small; on the contrary, the smaller the particle, the greater the viscosity . The particle size mentioned here refers to its original radius rather than the particle size of the pigment and filler re-agglomerated during the production process.
The viscosity of ink is low, close to Newtonian fluid, and the factors that affect the viscosity of general ink also affect ink . However, ink has its particularity, and the changes in the viscosity of ink are usually affected by the following three aspects.
