Polyethylene film
— used for a protective waterproof layer of diapers (mostly having a corona or micro-embossed surface – to give non-slip properties). Also, different types of films are used for packaging products and in the manufacture of some other products.
Films made of the following types of polyethylene are used:
Low density polyethylene (LDPE) – PE with a relatively highly branched macromolecule and low density (0.916-0.935 g/cm³). Its production process takes place at very high pressure of 100-300 mPa and temperature of 100-300 °C, therefore it is called the same as high pressure polyethylene (HDPE). LDPE film and bags are smooth and shiny and do not crumple. LDPE is more resistant to punctures and cuts.
High density polyethylene (HDPE) – PE with a linear macromolecule and a relatively high density (0.960 g/cm³). It is also called low-pressure polyethylene (HDPE) and is produced by polymerization with special catalyst systems. HDPE bags are dull and rusty, crumple more, but are very resistant to stretching and can withstand a heavy load, are more economical to produce.
Medium-density polyethylene (MDPE) — PSD have a density of 0.926 to 0.940 g/cm3. Medium pressure polyethylene PSD films and bags are made from a mixture of LDPE and HDPE, so they combine their properties depending on the proportions of LDPE and HDPE used.