What are the factors that affect the tension of the stretch film?
February 12, 2020
Stretch film , its external tension depends on the size of the plastic film's surface free energy, the external tension has many influencing factors, the main factors are as follows:
Influencing factor 1: Non-polar polymer, its surface free energy is small, the surface wet tension is low, generally about 30 dynes/cm. In general, if the external tension of the object is less than 33 dynes/cm, the ordinary ink or the adhesive cannot be firmly attached, and it is necessary to be surface-treated.
Influencing factor 2: Aluminized layer transfer occurs during aluminum plating, and the rubber layer transfer occurs when the glue is applied. The main measure to prevent the corona on the reverse side of the film is to adjust the pressure of the rubber pinch roller before 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 with a high surface free energy. However, for high-speed black printing or to increase the bonding between the vacuum aluminum plating layer and the appearance of the BOPET film, it is also necessary to externally treat the BOPET film to further improve the surface wet tension.
Influencing factor 4: When testing the external 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 roller smoothly and prevents the air from being trapped, thereby preventing the phenomenon of reverse corona.
