What Are The Factors That Affect The Tension Of The Stretch Film?

Stretch film, also known as stretch film and heat shrinkable film, its surface tension depends on the surface free energy of the plastic film. There are many factors affecting the surface tension. The main factors are:

Influencing factor 1: Non-polar polymers have small surface free energy and low surface wet tension, generally about 30 dynes/cm. Generally speaking, if the surface tension of the object is lower than 33 dynes/cm, ordinary inks or adhesives cannot be firmly attached, and surface treatment is necessary.

Influencing factor 2: The transfer of the aluminized layer will occur when aluminized, and the transfer of the coated layer will occur when the glue is applied. The main measure to prevent corona on the reverse side of the film is to adjust the pressure of the rubber pinch roller in front of the corona treatment roller. The pressure at both ends of the pinch roller should be consistent and the pressure should be appropriate.

Influencing factor 3: Polyester is a polar polymer, and its surface free energy is high. However, for high-speed black printing or to increase the bonding force between the vacuum aluminized layer and the surface of the BOPET film, the surface treatment of the BOPET film is also required to further improve its surface wet tension.

Influencing factor four: When testing the surface tension of the wrapping film, a strict dynamic and static balance test must be carried out to ensure that the plastic film enters the corona roll smoothly and prevents air from being trapped, thereby preventing the phenomenon of reverse corona.