EVOH

The abbreviation EVOH stands for ethylene vinyl alcohol copolymer. In flexible packaging, EVOH is used as a thin, organic barrier layer to protect products primarily from oxygen (and thus oxidation and aroma loss). In packaging films, EVOH is usually transparent and is therefore suitable for clear high-barrier packaging.

Properties

Application

EVOH is usually used as the middle functional layer in PP and PE films and is mainly used in food packaging such as bags, thermoformed films or tubes. The outer layers of PP and PE provide mechanical strength, sealing properties and an additional moisture barrier – the EVOH provides the oxygen and aroma barrier.

Barrier performance

In practice, EVOH primarily provides a very high oxygen barrier, which in turn can decrease depending on the relative humidity. In the overall composite, OTR and WVTR values of <= 1 are realistic, which means that EVOH barriers can be classified as ‘high barrier’ (depending on the overall composite and test conditions).

Recycling

Current design-for-recycling guidelines assess EVOH content of up to 5% differently depending on the polymer recycling stream and the complete packaging structure. EVOH content above 5% may cause recycling-process issues such as gel formation, increased haze and process instability. Our PE-EVOH-PE packaging structures are equipped with a 5 µm EVOH barrier in the middle layer.

Sources as of 23 January 2025: