Plastic film by gravure printing method after printing, can play a role in beautifying the packaging of goods, the goods have a good publicity, with other printed materials can not be compared to the unique advantages. However, the most commonly used polyolefin film materials (PE, PP, modified polyolefin, etc.) are non-polar polymers, the surface free energy is quite low, only 2.9 ~ 3.0 × 10-6J / cm2. In theory, if a surface free energy of less than 3.3 × 10-6J / cm2, it is almost impossible to pay any of the known adhesives. Therefore, to make the ink in the polyolefin surface to obtain a certain printing fastness, it must improve its surface free energy, according to the current process requirements, should reach 3.8 ~ 4.0 × 10-6J / cm2 Caixing. So far, the most commonly used at home and abroad the effective treatment of plastic film is corona treatment.


    As the corona treatment is generally carried out in the air, so in the high-pressure, high-frequency spark shock conditions, on the one hand the air ionization, resulting in a variety of polar groups; the other side of the polyene molecular structure of the double-stranded , In particular, its double chains on the chain are easier to open. In this way, at the moment of processing, the polar groups and the surface of the polymer graft reaction occurred, so that the polyolefin surface from non-polar to the polar surface. It can be said that after the corona discharge treatment of polyolefin surface, about a few 10-10m thickness has become completely different from the original polyolefin structure of the polar material, the surface free energy can be greatly improved, Up to 3.8 to 4.0 * 10-6J / cm2. At the same time, the high-pressure high-frequency spark will be the surface of the film material through the impact of hair (with a high magnification of the electron microscope observation, can be seen in the treatment of small groove-like uneven), thereby enhancing the ink infiltration and contact area. Thereby enhancing the adhesion of the ink on its surface by both 

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