1. Heat shrinkable film structure
The film structure of heat shrinkable film packaging is similar to that of paper. The difference is that the surface of the film must be treated.
2. Heat shrinkable film packaging surface treatment
The principle of the ink layer forming patterns on the printed matter is penetration, volatilization, conjunctivation, and curing. However, due to the high film density, the ink only volatilizes and conjuncts the film, and there is no penetration during the curing process, so the surface of the heat shrinkable film packaging needs special treatment. After treatment, the surface tension of the heat-shrinkable film is increased, so that the heat-shrinkable film is greater than the surface tension of the ink, so as to achieve the correct combination of the ink and the film material.
Three ways of surface treatment of heat shrinkable film packaging
1. Corona treatment: Discharge treatment to the surface of the film through high-voltage charges, so as to achieve the purpose of strengthening the surface energy and surface tension. The corona treatment is generally carried out in the film manufacturing plant. Because the surface tension is time-limited, it is required to be strictly tested before printing. Therefore, some advanced equipment has a pre-press corona treatment device in order to print high-quality film products.
2. Printing treatment: Use chemical methods to change the surface characteristics of the film to make it suitable for ink printing or ribbon printing.
3. Surface coating: Use chemicals to coat the surface of the film to increase surface tension and change surface characteristics.