PE film, that is, polyethylene film. Polyethylene plastics are classified into high density, medium density and low density. Generally, the density of linear low density polyethylene is 0.91 to 0.965 g/cm 3 (g/cm 3 ).
Its density is about 0.92 g/cm3. Low-density polyethylene film has good transparency and heat-sealing property, can be waterproof and moisture-proof; low tensile strength, large tensile elongation, easy to wrinkle, film below 0.03mm, tension control should be small, and tension everywhere It should be constant, especially when heated, it is more easily deformed, which makes it difficult to color. Therefore, when drying, the film surface temperature should not be too high (within 550C). According to different film forming processes, it can be divided into blown film (IPE), cast film (CPE), low foaming film and so on. The tensile strength and opening of the IPE film are better than that of the CPE film. It can be used as a food bag or a garment bag for front printing. The thickness of the CPE film is uniform, the surface gloss, transparency and heat sealability are better than PE, and can be printed on the front and back. However, the production cost is high. CPE film is mainly used as the inner layer of composite bag and packaging of cosmetics, pickles and cakes; low foaming film has good decorative property, thick texture, not easy to stretch and deform, and is printed on the front side, used for new year painting, trademark and hand bag.
Medium density polyethylene
Its density is between 0.93 and 0.94 g/cm3 and its performance is between high density and low density polyethylene.
The density is between 0.94 and 0.965 g/cm3. The high-density polyethylene film has better heat resistance and mechanical strength than the low-density polyethylene film, and has a small tensile elongation, and the film thickness is generally 0.03 mm or more, but the transparency is poor. It is printed on the front side and is mainly used as a vest bag, a garbage bag and a liner bag.