Most Flexo printers understand that in the process of printing with water-based ink, it is necessary to pay attention to the viscosity of the ink and maintain a certain degree. In the laboratory, the operator uses the Zahn cup and the stopwatch to observe and check the viscosity is the most common work. If the viscosity value of the ink is higher than the expected value, some water is generally added, but the problem will occur at this time. Too. If water is used alone to control the viscosity of the ink, each time water is added, the pH value of the ink will decrease as the viscosity becomes smaller. The pH value of water is 7, and the pH value of Flexo's water-based printing ink is generally controlled by the supplier, usually between 8.5 ~ 9.5. When the pH value drops, the interaction between the ink components will start to change, the lower pH value will have a significant loss of color intensity, and even more, the ink will start to separate or split to produce muddy phenomenon, high pH value It will also cause the loss of structure and composition. Today, pH is considered to be the most critical factor in controlling the mid-range of Flexo printing. Is pH more important than viscosity? The answer is right. However, when establishing and maintaining optimal printing ink, pH and viscosity are inseparable, and the two control each other. Use the correct viscosity adjustment fluid How to control the pH value and viscosity? First, you must use a pHmeter to detect the pH value, understand the pH value of all the ink components and additives, and record their changes at any time. Urban water use may vary by as much as one unit at different times of the month. In addition to adjusting the viscosity with water, another premixed adjustment liquid can also be used. This adjustment liquid contains some amounts of amines and other ingredients. Usually the adjustment liquid provided by the ink manufacturer can increase the pH of the printing ink by 1 ~ 1.5, you can no longer adjust the ink with water. Both pH and viscosity are the key to the success of printing. Under the establishment of printing, pumping, pattern rollers, measuring systems, printing plates, binding and backing operations, materials and drying, the ink has only the best viscosity And the best color can be obtained under the pH value. Many letterpress manufacturers have found that colors can come into contact with each other during overprinting, cylinder liner or color overprinting, so the most useful way is to increase the viscosity and lower the pH value. This method helps the drying process and avoids post-printing. The color is moistened by the previously printed color. For example, this method obviously requires more than one type of adjustment liquid to be added to each ink table to adjust the required viscosity. Furthermore, these adjustment fluids must be higher than the pH of each printing ink by 1.0 ~ 1.5. The significance of system automation In the process of using ink, the use of an automated viscosity and pH control system can effectively detect the stability of online ink, thereby reducing ink film and ink loss, and at the same time reducing volatile organic compounds (VOCs) (amines, The use of alcohol or other solvents) can save precious time for printing practitioners to do other important work. Today's newer generation of automatic control systems have excellent accuracy and reliability, can be easily operated and maintained, and both multi-unit or single-unit control systems can be purchased at a cheaper price than before, and some will even provide SPC / ISO report. Finally, it must be mentioned that, whether it is an automatic system or manual operation, the most important thing is to adjust the use of liquid, rather than using water. Our company is a manufacturer of stainless steel kitchen product series with independent research and development, sales and production capacity. Our stainless steel Kitchen Product Series are the preferred partner for customers around the world with low price, good quality and professional service. Stainless steel Kitchen Product Series arewidely used in hotels; western restaurants; coffee shops; family gatherings; company parties. Stainless Steel Kitchenware Set Stainless Steel Kitchenware Set,Kitchenware Set,Stainless Steel Cookware Set,Cookware Set HY-STAINLESS STEEL INDUSTRIAL CO.,LTD. , https://www.cnhuangyi.com
PH and viscosity control of water-based printing ink