Squeeze bottles made of LDPE / PE-LD (low-density polyethylene)

Polyethylene is the most commonly used thermoplastic worldwide and is widely used in the packaging industry in particular. Depending on the structure of the polymer chains, a distinction is made between three main types: HDPE (high-density polyethylene), LLDPE (linear low-density polyethylene) and LDPE (low-density polyethylene).

LDPE is characterised by highly branched polymer chains. This irregular molecular structure prevents the chains from packing tightly, resulting in lower crystallinity (typically 40–55%) and a lower density of around 0.91–0.93 g/cm³. This structure results in high flexibility, toughness and transparency, while at the same time mechanical strength and temperature resistance are lower than those of HDPE.

The key material properties of LDPE include:
High elasticity and deformability, ideal for flexible applications such as squeeze bottles, hoses or films.
Good impact strength, even at low temperatures.
High transparency compared to HDPE, making it attractive for packaging.

Low chemical resistance: while LDPE is resistant to many aqueous solutions, it is significantly more sensitive to organic solvents, oils and fats.
Low water vapour permeability, but slightly higher gas permeability compared to HDPE.

Good processability in processes such as blown film extrusion, extrusion blow moulding and injection moulding.
Typical applications include films for food packaging, carrier bags, stretch and shrink films, squeeze bottles, hoses, insulation materials for cables and flexible moulded parts. Due to its ease of processing and good recyclability, LDPE remains a key material in the plastics industry.