Its density is about 0.92g / cm3. Low density polyethylene film has good transparency and heat sealability, can be waterproof and moisture proof; low tensile strength, high tensile elongation, easy wrinkling, 0.03mm thin film, the tension control should be small, and the tension To be constant, especially when heated more easily deformed, causing color sets difficult. Therefore, when dry, the film surface temperature should not be too high (within 55 degrees). According to the different film-forming process, can be divided into blown film (IPE), drooling film (CPE), low foaming film and so on. IPE film tensile strength and opening than the CPE film is good, the use of positive printing, can be used for food bags, garment bags, etc .; CPE film thickness uniformity, surface gloss, transparency and heat sealing than PE, can be positive and negative printing, But the high cost of production. CPE film is mainly used as the inner layer of composite bags and cosmetics, pickles and cakes packaging; low foaming film decorative good, thick texture, not easy to stretch deformation, the use of positive printing, used for New Year, trademarks and Shoulin bags.
Medium density polyethylene
Its density is about 0.93 ~ 0.94g / cm3 performance between high density and low density polyethylene.
Density of 0.94-0.965g / cm3. High-density polyethylene film heat resistance, mechanical strength than low-density polyethylene film, tensile elongation is small, the film thickness is generally 0.03mm above, but the transparency is poor. Front printed, mainly used as a vest bag, garbage bags and lined bags.
Because of its higher than other polyethylene products, heat resistance, tensile strength, heat shrinkage and barrier properties, its use is further expanded in 2014, mostly used as heat shrinkable film packaging.
In general, as the density increases, the mechanical and barrier properties will be correspondingly improved, and the heat resistance will be good. The same density of polyethylene, due to the different film-forming process, they also have different properties. This is because the salivating method can rapidly cool, low crystallinity, high transparency, low turbidity, but the molecular arrangement more irregular state, so less barrier, that is, a larger transmittance, lower elongation, tear resistance Poor crack.