Rotogravure how to make ink viscosity to achieve ideal2016.12.05 11:00
In the plastic gravure printing, how to control the printing ink viscosity is a critical problem.
Printing ink viscosity and viscosity is very different, but they still have a contact. Mainly in viscosity is measuring the size of the fluid viscous parameters, dynamic viscosity of the fluid is determined by the intrinsic to the fluid physical properties, its value is a direct measure the size of fluid viscosity, and the movement of the fluid a measure of resistance to shear deformation ability strong or weak. In the same condition, the viscosity said big viscosity, and vice versa.
How to control in high speed rotary gravure printing ink viscosity? We want to make resin, pigments and organic solvent such as colloid system is not in the supersaturation state, but is saturated or unsaturated state, can make pigment substances such as well dispersed among them, form the uniform fine colloid system, such pigments in and out of mesh smoothly, can solve the problem.
In the plastic gravure printing, but also often dirty version problems. The root cause of dirty version phenomenon in addition and hardness of scraper, squeegee pressure, blade contact Angle, the quality of the plate cylinder and so on, mainly related to the viscosity of printing ink. Generally speaking, the printing ink viscosity is small, dirty version phenomenon is not likely to happen. However, if the printing ink viscosity is too small, printing ink, organic solvent content in the resin, pigments and other components is relatively less, so can't in dry form a smooth film, printing quality will be suffused with white, become dull, lack of gloss. As a result, such as printing quality needs to have good gloss, generally want to consider using a larger printing ink viscosity (13 ~ 19 s, zahn 3 cups), namely, resin, pigment composition is relatively more, to meet the needs of the printing quality.
Usually at 11 ~ 17 s (zahn 3 cups) for printing ink viscosity between the ideal state of points. If appear electrostatic phenomenon in this scope, based on the principle of balance each other, usually don't have to improve the printing ink viscosity method to eliminate static electricity, but by keeping normal environment humidity, change thinner composition structure, installation in addition to static brush, use methods of antistatic agent to eliminate static electricity. Such ability in quality assurance at the same time, improve efficiency and yield, as to lay a necessary foundation for printing enterprise profit.