The environmental humidity of the film shop has an impact on the quality of the coating film. The main reason is that the moisture content changes with the relative humidity of the air between the adhesive and the plastic film and the printed matter. Humidity-sensitive prints can develop internal stresses due to dimensional changes.
For example, the longitudinal stretch rate of the printed matter is 0.5%, and the longitudinal shrinkage of the BOPP film is 4%. If the water absorption of the printed material is excessive and the film stretches, and internal stress is caused between the heat shrinkage of the film, the film product may curl and wrinkle. Bonding is not strong. In addition, in a high humidity environment, the equilibrium moisture content of the printed matter will also change, and the large amount of moisture absorbed from the air medium will be released from the surface during the hot-press compounding process, stagnating at the adhesive interface, and being formed locally. Non-adhesive phenomenon. Moreover, changes in the balance of moisture in the printed matter (absorbing moisture from the air medium or releasing moisture into the air medium) often occur at the edge of the print, making it a scalloped edge or a tight edge, and it is not easy to form a film with the film during hot press compounding. Good adhesion produces wrinkles, making production unsuccessful.
Reprinted from: Parker Packaging