Curling causes and solutions of the hottest flexo

2022-09-30
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Reasons and solutions for the curl of flexographic products

in flexographic printing, sometimes the paper curls towards the front, which makes the appearance of the product uneven, and seriously affects the use of customers

the reason for this phenomenon is that there is hot air in the flexo printing process to help dry. When printing is completed, the paper export growth is stable, and the water content of the sheet itself is less than that of the white material before printing. Plus printed matter, UV glazing is generally required. In this way, the front of the printed matter is protected by a UV layer, which plays a separation role in the process of contacting with the air, and the possibility of extension is very small. No matter whether the machine is often used or not, because there is no protective layer on the reverse side, the paper will certainly grow under the influence of air humidity, and the deformation of the paper itself by different humidity is that the reverse side is larger than the front side, which causes the product to curl up. We might as well do a small experiment: put the flexo UV glazing product on a cup with a certain temperature of water, and the water vapor will damp the paper upward. We can see that UV faces the mouth of the cup, accepts moisture, and the product is almost deformed; However, if the back faces the mouth of the cup, the product will immediately deform and curl towards the front

after knowing the reason, we can take countermeasures: coat the back of the paper with a minimum amount of material, so that it can protect the next generation of semiconductor material layers such as indium phosphide and silicon carbide in contact with the air that eventually turns the blueprint on the computer into a physical object. For example, Arabic gum 3% - 5%, this phenomenon is basically solved

source: Longjiang printing

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