AlOx - aluminium oxide

The abbreviation AlOx stands for aluminium oxide and describes an ultra-thin, high-barrier inorganic coating that is usually applied to PET and BOPP films using a vacuum process. AlOx barriers are applied to the carrier film with a thickness in the nanometre range and are transparent.

AlOx is primarily used in transparent food films, for example to provide PP mono-materials with very high barrier performance. AlOx is applied to a carrier film such as BOPP and replaces traditional aluminium barriers in many applications.

AlOX-coated films have very high oxygen and water vapour barriers, which can be impaired by mechanical stresses such as kinks. OTR and WVTR values of <= 0.5-1 are possible for AlOx barriers, which means they can be classified as ‘high barrier’ (depending on the overall composite and test conditions).

PP-based flexible packaging with an AlOx barrier without additional coatings may be suitable for recycling when the complete packaging structure meets the applicable design-for-recycling criteria.for-recycling assessments. According to the RecyClass Design for Recycling Guidelines for natural PP flexible films, AlOx without additional coatings is classified as fully compatible for the barrier criterion, whereas EVOH up to 5% in a polyolefin combination film is classified as limited compatible. The recyclability of the complete packaging structure must nevertheless be assessed separately.