Low Density Polyethylene (LDPE) is a semi-rigid and translucent polymer. It is produced at high pressure (1000-3000 bar; 80-300°C) via free radical polymerization process. The LDPE is composed of 4,000-40,000 carbon atoms, with many short branches. Two basic processes used for the production of low density polyethylene: stirred autoclave or tubular routes. The tubular reactor has been gaining preference over the autoclave route due to its higher ethylene conversion rates.
Properties of Low Density Polyethylene
Chemical resistance of LDPE:
Good resistance to alcohols, dilute alkalis and acids
Limited resistance to aliphatic and aromatic hydrocarbons, mineral oils, oxidizing agents and halogenated hydrocarbons
Temperature resistance up to 80°C continuously and 95°C for shorter times.
Low cost polymer with good processability
High impact strength at low temperature, good weatherability
Excellent electrical insulating properties
Very low water absorption
Transparent in thin film form
Low Density Polyethylene (LDPE) uses majorly revolve around manufacturing containers, dispensing bottles, wash bottles, tubing, plastic bags for computer components, and various molded laboratory equipments. The most popular application of low density polyethylene is plastic bags.
Packaging – Thanks to its low cost and good flexibility, LDPE is used in packaging industry for pharmaceutical and squeeze bottles, caps and closures, tamper evident, liners, trash bags, films for food packaging (frozen, dry goods, etc.), laminations etc.
Pipes and Fittings – Low Density Polyethylene is used to manufacture water pipes and hoses for the pipes and fittings industry due to Its plasticity and low water absorption.
Other applications include consumer goods - housewares, flexible toys, agricultural films, wiring & cables - sub-conductor insulators, cable jacketing.