Drying characteristics of the hottest water-based

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Drying characteristics of water-based ink

when using water-based humor, we all know that generally, if the water-based ink dries too slowly, the printed matter will dry poorly, the ink will stick to the paper guide roller, and the printed matter will lose its luster, which will also affect the overprint effect and cause problems in the quality of printed matter. However, if the water-based ink dries too fast, it will transfer poorly, which is easy to cause blocking, and the imprinted edge will appear jagged, and the ink will dry to the surface of the printing plate. If the water-based ink dries too fast, it will also cause Scratch on the surface of the printed matter when printing the line plate. The reason is that the ink has dried before it penetrates the surface of the substrate during the printing process, causing the ink to suspend on the surface of the substrate and be wiped off. Therefore, the drying of water-based ink is a crucial issue. Here are some technical guidance on its drying for your reference

for the drying problem of flexo printing water-based ink, there are the following technical guidance:

first, try to make the drying speed of ink slower in the printing process without affecting the printing speed. This can slow down the classification of the current experimental machine and adjust it with fine drying agent. Different manufacturers of ink need to add different amount of slow drying agent, generally no more than 5% to provide them with carbon fiber semi curing materials. After adding slow drying agent, the ink will thicken and the pH value will decrease. Therefore, when adding slow drying agent, water and stabilizer should be added to control ink viscosity and pH value

second, properly increase the pH value of the ink to reduce the drying speed of the printing process without affecting the drying speed. The pH value is generally controlled at 8.5 ~ 9.5. If the drying is too fast, add a stabilizer to control the pH value above 9, but not more than 9.5, otherwise the ink properties will change. The surface tension of ink is low, the line version is easier to block, and the drying will become slower

third, when printing thin paper products, reducing the drying speed of ink can reduce the warpage of paper. This usually needs to be adjusted by adding slow drying agent or blocking agent. The reason is that the water and alcohol in the water-based ink volatilize after printing, which loosens the tight sides in the middle of the paper and produces warpage. The function of adding slow drying agent is to prevent the ink from drying out instantly and reduce warpage

fourth, enhancing the convection speed of the oven air can significantly accelerate the drying speed of printed matter. Because the water-based ink contains a lot of water and alcohols, enhancing convection can reduce the relative humidity in the oven and accelerate the evaporation of the solvent

fifth, if we use a large amount of ink in our printing products, we should try to use ink with high color concentration and wrinkle rollers with a high number of lines, which is conducive to the drying of printed products and can also reduce the phenomenon of water marks

sixthly, adding slow drying agent can solve the problem of scratch of printed matter and surface dirt of polished plate. Too fast drying of the ink will cause the ink to dry and fix on the surface of the substrate without entering the penetration stage, resulting in insufficient adhesion, and the ink layer is easy to fall off. When overprinting or polishing, the latter color printing plate will stick the ink of the previous color, which can also be adjusted by changing the color sequence or reducing the ink viscosity

seventh, adding slow drying agent and speeding up can reduce the blocking phenomenon. Too slow printing speed will make the ink diffuse on the printing plate, causing point adhesion. However, too fast drying of the ink will make the ink unable to be fully transferred, resulting in ink accumulation around the point, which can improve the dispersion of fillers, improve the storage length of glass fiber, and improve the floating fiber, resulting in blocking

eighth, the paper guide roller is heated, which can also accelerate the drying speed of printed matter. When we use a large amount of ink when printing products, if the drying capacity of the printing machine is limited, and the speed is not fast when we start up each time, there is a certain room for improvement after a period of time, which is the reason why the paper guide roller is hot. After the paper guide roller is heated, the ink is not easy to stick to its surface. Before starting the machine, the independent drying device is turned on in advance. When the machine is just started, the air suction device can be turned off first, so that the equipment can accumulate the maximum mechanical performance stable heat in the shortest time, and the speed can be quickly increased

ninth, higher printing speed requires lower ink viscosity, which is conducive to ink transfer

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