Stretch film formula
July 15, 2019
Stretch film, also known as elastic film or wrap film, has high stretching temperature, tear strength and good retraction memory and unique self-adhesiveness, which can tightly wrap the object into a whole and prevent scattering during transportation. collapse.
One of the formulations of the wrap film is to add PIB or its masterbatch to the polymer, and the other is to blend VLDPE. PIB is a translucent viscous liquid. Direct addition requires special equipment or equipment modification. PIB masterbatch is generally used. There is a process for the removal of PIB, which usually takes three days. In addition, it is also affected by temperature. When the temperature is high, the film is sticky. When the temperature is low, the film is not sticky, and the stretch film is greatly reduced after stretching.
As the number of C-atoms of the comonomer of the material of the wrapping film increases, the length of the branch increases, the crystallinity decreases, and the effect of the "coiling or kinking" of the resulting copolymer increases, so the elongation of the stretched film increases, and the puncture of the stretched film Both strength and tear strength are also improved. MPE is a high stereoregular polymer with a narrow molecular weight distribution, which can accurately control the physical properties of the polymer, so it has further improved the properties of the wound film. Because of the narrow molecular weight distribution of MPE, the processing range is narrow, and the processing conditions are difficult to control. Usually, 5% LDPE is added to lower the melt viscosity and increase the flatness of the wound film. The material density also affects the properties of the wound film
