Fluidity and fluidity are the most intuitive performance of ink. Their quality relates to the transfer of ink, transfer status.
Mobility. When the ink is affected by external forces, it flows in all directions and opens. Under the condition of the same force, the larger the flow distance (spreading diameter) is, the better the fluidity is. Recently, the size of the stress spreading in one minute is called the maximum "flow". Of course, liquidity is also a part of liquidity.
If the flow is too small, the ink can not be spread smoothly and evenly, resulting in a deep after light or on the contrary, the ink supply is not normal.
Its color, not clear, and so on.
Fluidity is closely related to the viscosity, viscosity and consistency of ink. With the increase of viscosity, the fluidity decreases, and vice versa. However, if the viscosity is large, the fluidity may not be reduced. High consistency does not mean that the viscosity is large, nor does it mean that the viscosity must be large. The viscosity of the ink is not necessarily thick, the same viscosity (degree) of ink, consistency, then the fluidity (property) is poor.
mobility. Do not subject to external forces, ink instinct has the flow called liquidity. This index is very important for thin, low viscosity liquid ink, such as news ink and roll coating ink. It is a certain amount of ink, placed on a vertical, smooth glass plate, measured in a certain period of time flow distance. From this we can see that it is the ink by gravity, ink gravity, laminar flow sliding friction resistance.
The fluidity is greatly affected by the viscosity, yield value and thixotropy of the ink. It is closely dependent on temperature.
For Newtonian fluid or similar Newtonian fluid ink, viscosity size, can generally explain its flow performance. For yield value, thixotropy of the ink fluid can not explain the problem.
In most cases, it is not consistent with the viscosity index, thin and low viscosity ink, not the fluidity is big, thick and viscosity of the ink, also is not the fluidity is small, here is mainly with the solid-liquid two-phase ratio, and the polymer polymerization degree and solvent ratio in the binder.
Liquidity and leveling are closely related. Leveling is actually the liquidity under specific conditions. This is more important in gravure printing, roll coating ink.
We hope that after the ink is developed on the printing body, and before the polymerization drying or solvent equilibrium is removed, due to the gravity of the ink itself and the molecular movement, the surface of the printed matter will be smooth and even. This means that leveling is good. If there are ripples, orange peel like surface, not only ugly, but also affect the luster, this is poor leveling.
However, if the leveling property is too high, it will flow continuously in one direction on the printing surface before drying, resulting in flow marks or uneven ink layer, which is the so-called sagging phenomenon. This is something that people have to control.
From the above analysis, it can be seen that Newtonian fluid with low viscosity has good leveling performance, but the chance of sagging may be more. Because of its own gravity and molecular motion force, the ink with plastic flow property can not overcome the yield value, and the leveling property is poor, and the sagging has inhibition effect.
Dongguan Beite packaging materials Co., Ltd. - located in Dongguan City, the world's manufacturing city, is a subsidiary of Beite packaging (China) Co., Ltd., with a plant area of 6000 square meters. It is a flexible packaging enterprise integrating R & D, production and sales. It has a complete set of domestic advanced production equipment, a scientific and humanized management system and a group of experienced technical personnel For backing, to provide customers with quality products and first-class service.
The company produces composite bags, roll film, fruit bags, aluminum foil bags, suction mouth bags, self-supporting bags, zipper bags, anti-static bags, special-shaped bags, etc., which are suitable for the internal and external packaging of food, daily chemicals, electronics, toys, medicine, cosmetics, industrial products and other industries.
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