The density of polyethylene film is 0.94-0.965g/cm3. High-density polyethylene film has better heat resistance and mechanical strength than low-density polyethylene film, and has a lower tensile elongation. The film thickness is generally above 0.03mm, but its transparency is poor. It is printed on the front and is mainly used for vest bags, garbage bags and lining bags. Because it has higher heat resistance, tensile strength, heat shrinkage and barrier properties than other polyethylene products, its use is further expanded. In 2014, it was mostly used as a heat shrinkable packaging film.
Generally speaking, as the density increases, the mechanical properties and barrier properties will increase accordingly, and the heat resistance will be better. Polyethylene of the same density has different properties due to different film forming processes. This is because the salivation method can cool quickly, with low crystallinity, high transparency, and low turbidity, but the molecular arrangement tends to be more irregular, so the barrier property is small, that is, the permeability is large, the elongation is low, and the tear resistance Poor rupture.
