Low-density polymers LDPE and PEBDL

Radical low-density polyethylene (LDPE) was discovered in Great Britain by ICI just before the Second World War. It was first used to insulate radar cables. Around 1950, low-density polyethylene began to be developed on a large scale. These polyethylenes have a density of between 0.915 and 0.935 g/cm ³ and are manufactured by high-pressure ethylene polymerization processes. Ethylene polymerization then follows the mechanisms of free-radical chemistry. These low-density polyethylenes (LDPEs) are therefore sometimes also referred to as radical PEs or high-pressure PEs.

In the late 1970s, Union Carbide developed linear low-density polyethylene (LDPE) using a low-pressure process with Ziegler-Natta catalysts. The corresponding production centers offer a wider range of products than high-pressure units, producing high-density polyethylene (PE-HD) (density 0.935 to 0.970), PE-BDL (density 0.915 to 0.935) and even very low-density polyethylene, PE-tBDL.

Finally, in 1993-1994, PE-BDLs manufactured using the same low-pressure processes, but with new metallocene catalysts, came onto the market.

The various low-density polyethylenes (density from 0.860 to 0.935) are characterized by Young's modulus ranging from 10 MPa to 500 MPa, good dielectric properties, low water vapor permeability and good resistance to stress cracking.

PE-BD and PE-BDL are mainly used for packaging foodstuffs and various industrial products, as well as in cabling, geomembranes, sealing film, pipes and masterbatches.

Film applications account for around 70% of the total low-density polyethylene market in terms of tonnage. LDPE is also used for extrusion coating on paper, cardboard or aluminum foil.