Polyethylene

Front view of a bird water bottle showing the open beak and adhesive eyes.

(HDPE)

Side view of a cup and saucer showing the moulded line decoration around the cup.

Front view of a Sqezy bottle showing the printed design.

(LDPE)

Acronym and details: PE, low-, medium- and high-density: LDPE, MDPE, and HDPE

Group: thermoplastic

Developed: 1933 low density but used for military purposes until 1945; 1953 high density

Trade names: Polythene; Alkathene; Tyvek

Manufacturing process: blow moulding; extrusion; injection moulding; rotational moulding

Cost: very low

Colour: any

Transparency: naturally translucent but can be opaque

Rigidity: semi-rigid to flexible depending on density

Feel: varies depending on density

Smell: wax

Other: scratches with fingernail; currently LDPE is the plastic with the highest volume of use

Typical uses: replaced enamelled kitchenware: bowls and other domestic wares, first squeezable bottles (e.g. for washing up liquid) and airtight food containers; road cones; ‘poppit’ beads; packaging film, e.g. carrier bags

Degradation: yellows, stiffens, and embrittles