Consumers may like them, but recyclers are less enthusiastic: so-called composite packaging, in which a cardboard carrier is coupled with a thin polymer layer to ensure the required barrier properties or sealability, can be found on shop shelves with increasing frequency.

But when it comes to recycling, it’s precisely this intimate connection that makes separation by packaging type virtually impossible. Nevertheless, can these hybrid solutions be made more recyclable?

Propakma (Bietigheim-Bissingen, Germany; www.propakma.com) has analysed this on behalf of French waste management group Veolia (Paris; www.veolia.com) and recycling alliance Forum Rezyklat (www.forum-rezyklat.de).

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The study, entitled Fundamentals of Fibre-Based Packaging With Barrier Coating – Requirements for the Barrier, provides a 42-page overview of the legal framework and disposal routes for composite packaging, defines the barrier types and their properties, and determines their respective recyclability.

According to the author, Arne Krolle, the “ideal” barrier has the following properties: mechanical sortability, microbial stability, surface charge (anionic), a certain thermal behaviour (stickiness > 105°C), hydrophobicity, and removability of the barrier film.

Furthermore, the use of compostable bioplastics is not recommended, due to microbial degradation in paper production.

Guido Adomßent, COO of Veolia Umweltservice, said that the study aims to help packaging distributors to differentiate more easily between the materials and to better categorise their respective recyclability.