Low-density Polyethylene: How it’s made, Properties, Uses and The Olden Days


Resin Identification Code, LDPE, LLDPE, 4
LDPE

How is it made?

Similar to HDPE, Low-density Polyethylene occurs after the polymerisation of Ethylene, what differs is that it goes through a different polymerisation mechanism resulting in a weaker, more flexible material.



Properties

Its toughness, flexibility and transparency give the abbreviated LDPE an excellent combination to packaging requiring heat-sealing. Plus, it is resistant to acids and vegetable oils.


Linear low-density Polyethylene (LLDPE) follows the same structure of LDPE, however butene, hexene and octene are added granting it a higher tensile strength, which means is more stretchable than LDPE.


Both compete in the same markets, though.



Common Uses

LDPE’s demand is majorly for film applications like plastic and bubble wrap, bread and sandwich bags.

It can also be used as a coating for hot and cold beverages cups as well as container lids. Rubbish/ garbage bags, wire and cable insulation/covering, adhesives and sealants. Due to its flexibility, it’s one of the favourites for squeezable bottles


When properly recycled some of its uses include: plastic lumber, compost bins, floor tiles, furniture and panelling.



The olden days

Initially produced in 1933, Imperial Chemistry Industries (ICI) was only granted the patent in 1937. Shortly after, a full-scale production was put in motion in order to manufacture insulator for radar cables, meant to be used throughout World War II.