Solution to the problem of peeling off of the most

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Solution to the problem of peeling and falling off of the polishing plate

when using the UV polishing machine made in Tianjin to locally polish the coated prints, it is necessary to use double-sided tape to paste the flexible plate for polishing on the plate cylinder, but the flexible plate is always unable to be fixed well. After the equipment runs for a short time, the periphery of the plate will be tilted and peeled, causing the edges of the polishing pattern to be irregular and the yield to be greatly reduced. Later, it was changed to first install a layer of PS version on the drum, and then paste the flexographic version on the PS version with 502 glue, double tube glue, etc., but the effect was not ideal. After analysis, it is considered that the above phenomenon occurs because the benzene, ketone, ether, alcohol and other organic solvents contained in the diluent and photosensitizer in UV oil are corrosive

in order to solve the above problems, we chose another material -- old blanket as the glazing plate. The reason why we choose blanket is because of the former phenomenon: it is mostly caused by the drying of gauze on the wet ball sensor. The blanket is composed of five layers of structure, which can be peeled off. When making the polishing plate, first make a die-cutting plate according to the requirements of the polishing pattern, install it on the machine, adjust the pressure to a moderate level, and die-cut the old rubber blanket. Note: only the upper three layers are cut through, and the lower two layers need Markey's simple formula: keep it complete; Then peel off the unwanted part of the blanket and install it on the plate cylinder of the glazing machine for UV glazing

since there are only two layers of cloth left in the blanket, it is not only elastic, but also flexible. In order to prevent it from moving in the glazing process, double-sided tape should be stuck at the corresponding position under the cloth layer. The glazing effect is very good. The problems of peeling and falling off of the glazing plate in the original production have been completely solved, but the following phenomena have appeared in the printed matter after glazing:

1 The brightness of the printed matter after glazing is not enough

2. The polished pattern is flowery

3 The glazing film is not wear-resistant and peels off

we adjusted the factors such as varnish coating amount, pressure, speed and curing time, but it didn't work. Through the comparison and analysis of the coated film and UV oil, it is considered that it is caused by the following reasons:

1 Before coating, the film was not corona treated, resulting in poor bonding ability between varnish and film

2. The selected glazing oil is not a high-quality friction resistant UV varnish for film materials (this kind of glazing oil has special additives, which can improve the friction resistance of the glazing film)

3. Improper curing time. Generally, the curing time should be controlled within 0.2 seconds and should not be too long, because the paper passes through the high-temperature area. If the surface dehydration is serious, the surface properties of the paper will be damaged, and the phenomenon of pulverization will occur, which will inevitably affect the friction resistance of the glazing film

4. Ink and varnish are not cured. The ink layer and glazing oil must be thoroughly dried and cured, otherwise 5. The adhesion fastness and wear resistance of the adjusting electromechanical speed cannot meet the requirements

5. The viscosity of the selected glazing oil is inappropriate. According to the running speed of the machine 20 ~ 50 meters/minute, the glazing oil with viscosity not less than 35 seconds should be selected, and generally the glazing oil with viscosity of 35 ~ 80 seconds should be selected

according to the above analysis, replace the UV varnish, adjust the curing time accordingly, and conduct film corona treatment while the product is coated (be careful not to reverse the corona surface of the film). The above problems are solved, and finally produce qualified and satisfactory products

Erdos Dongsheng packaging and Printing Co., Ltd. chenyunji

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