How to reduce the viscosity of water-based ink?
Date: Aug 19 2024 From: Star Color
Viscosity is one of the important characteristics of fluids. When a liquid is stirred, its flow velocity is proportional to the force used, and this proportionality constant is the viscosity of the liquid. It is a measure of the resistance to fluid flow caused by the interaction between fluid molecules that impedes their relative motion ability. The unit of viscosity is usually expressed in pascal seconds (Pa · s), or seconds (such as the number of seconds measured using a viscosity cup).
Viscosity is one of the most important indicators in the application of
water-based ink, which directly affects the transfer performance of ink, printing effect, and the quality of printed products. Ink with appropriate viscosity can ensure uniform, clear, and stable ink color during the printing process.
When the viscosity of water-based ink is too high, the following problems can occur:
When the ink breaks, it may exhibit a wire drawing phenomenon.
Reduce printing speed and affect printing efficiency.
Slow ink transfer may affect the transfer performance of the mesh roller, resulting in uneven ink color, insufficient color printing, and problems such as dirty and paste printing.
Methods to reduce the viscosity of water-based ink:Adding water: The most direct method is to dilute water-based ink by adding an appropriate amount of purified water, thereby reducing its viscosity. This method is simple and easy to implement, but it should be noted that adding water may affect the drying speed and printing effect of the ink. Therefore, it is necessary to add an appropriate amount and observe the effect. Generally, the water content should not exceed 10%.
Use diluents: In addition to pure water, specialized diluents or a mixture of water and ethanol (such as a 1:1 ratio) can also be used to dilute water-based inks. The amount of diluent should be controlled within a certain range (such as within 3%) to avoid excessive impact on the color depth and pH value of the ink. At the same time, adding a large amount of diluent for dilution may lead to the generation of bubbles. In this case, defoamers can be added simultaneously for defoaming treatment.
Using a fading agent: The fading agent is mainly used to reduce the depth of color, but when added in large quantities, it may cause a slight increase in ink viscosity. Therefore, while reducing viscosity, if color depth needs to be adjusted, a suitable amount of fading agent can be used, and the change in viscosity should be observed carefully. At this point, a small amount of diluent can be added simultaneously for adjustment.
matters needing attention:Monitoring pH value: During the dilution or addition of additives, it is necessary to closely monitor the pH value of water-based ink. The pH value of general water-based ink should be controlled between 8.0-9.5. If the pH value is too high or too low, it may have adverse effects on the viscosity and drying speed of the ink.
Zhongzhixing Color is a comprehensive enterprise that integrates production, processing, and sales. Its main products include water-based ink, UV ink, etc. The company strictly follows the ISO9001:2015 quality management system, and its products comply with multiple international standards, such as EN71 Part 3, ASTM F963-07 toy standard, 94/62/EC packaging material standard, ROHS heavy metal new testing directive, US FDA food control directive, and REACH (236 SVHC highly concerned substances) directive.
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