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The use of packaging materials is also different
Apr 28, 2018

The surface tension of the plastic film depends on the surface free energy of the plastic film, and the surface energy of the film depends on the molecular structure of the film material itself. Most plastic films such as polyolefin films (LDPE, HDPE, LLDPE, PP) are non-polar polymers, have a small surface free energy and a low surface wet tension, typically about 30 dyne/cm. In theory, if the surface tension of the object is lower than 33 dyne/cm, ordinary inks or adhesives cannot adhere firmly, so they must be treated on the surface. Polyesters (PET, PBT, PEN, PETG) are polar polymers with a high surface free energy and a surface wet tension of 40 dyne/cm or more. However, for high-speed color printing or for increasing the bonding force between the vacuum aluminizing layer and the BOPET film surface, it is also necessary to perform surface treatment on the BOPET film to further increase the surface wet tension.

Commonly used plastic films include polyethylene (PE), polyvinyl chloride (PVC), polystyrene (PS), polyester film (PET), polypropylene (PP), nylon, and the like. The performance of various plastic films is different, the degree of difficulty in printing is also different, and the use as a packaging material is also different.

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