? 1. Good adhesion makes the packaging film layer and the outer layer of the goods stick together, making the goods firm. There are two main ways to obtain viscosity: one is to add PIB or its masterbatch to the polymer; The other is mixed VLDPE.
2.PIB is a semitransparent viscous liquid, which requires special equipment or modification equipment directly. PIB masterbatch is generally used. There is a process for PIB to move out, which usually takes three days. In addition, it is also affected by temperature, which is sticky when the temperature is high. It will not be too sticky at low temperature, and the viscosity will be greatly reduced after stretching. Therefore, it is best to store the finished film in a certain temperature range.
? 3. the viscosity of mixed VLDPE is slightly poor, but there is no special requirement for equipment. The viscosity is relatively stable, not controlled by time, but also affected by temperature. When the temperature is higher than 30℃, it is relatively viscous, and it is slightly worse when it is lower than 15℃. The required viscosity can be achieved by adjusting the amount of LLDPE in the adhesive layer.
It should also be noted that high-quality stretched films should have high transparency, high longitudinal elongation, high yield point, high transverse tear strength and good puncture performance. Ming' an packaging