What is the density of common PE films?1

PE film, namely polyethylene film. Polyethylene plastics are divided into high density, medium density and low density. Generally linear low density polyethylene Density: 0.91—0.965g/cm3 (g/cm3). The density of low density polyethylene is about 0.92g/cm3. Low-density polyethylene film has good transparency and heat-sealability, and can be waterproof and moisture-proof; low tensile strength, high tensile elongation, easy to wrinkle, film below 0.03mm, the tension control should be small, and the tension everywhere It should be constant, especially when it is heated, it is more likely to be deformed, causing difficulty in color registration. Therefore, when drying, the surface temperature of the film should not be too high (within 550C). According to the different film forming process, it can be divided into blown film (IPE), cast film (CPE), low foaming film and so on. The tensile strength and opening of IPE film are better than CPE film, and it can be used for food bags, clothing bags, etc. with front printing; CPE film has uniform thickness, better surface gloss, transparency and heat sealability than PE, and can be printed on both sides. But the production cost is high. The CPE film is mainly used as the inner layer of the composite bag and the packaging of cosmetics, pickles and cakes; the low-foaming film has good decorative properties, thick texture, and is not easy to be stretched and deformed. The density of medium density polyethylene is about 0.93 ~ 0.94g/cm3, and its performance is between high density and low density polyethylene. The density of high-density polyethylene is 0.94—0.965g/cm3. The heat resistance and mechanical strength of high-density polyethylene film are better than that of low-density polyethylene film, and the tensile elongation is small. The film thickness is generally above 0.03mm, but the transparency is poor. With front printing, it is mainly used as vest bag, garbage bag and liner bag, etc.