Multilayer

A combined dissolution, delamination and catalysis approach to upcycling of multilayered packaging materials


In a nutshell

Multilayer seeks to combine various recycling techniques to recover the most valuable materials from multilayer plastic packaging, which is currently extremely difficult to recycle.

High-performance packaging
Multilayer plastic packaging plays a key role in the optimal preservation of many food products. By combining different layers of polymers, multilayer plastic packaging offers outstanding stability and barrier performance, protecting food products from water or oxygen permeation.

Over the last decades, these multilayer materials have been optimised to the best compromise of performance, cost and raw material usage. In fact, multilayer plastic packaging on the market today requires only a limited mass input of polymer material.

Recycling remains challenging
As of today, recycling used multilayer plastic packaging remains challenging. Current recycling technologies are able to successfully identify the main polymer backbone on the outside of multilayer materials, but they often miss the minor constituents of the packaging such as barrier and tie layers, which are nevertheless present in significant amounts.

Back to monolayer?
Switching back to monolayer materials is, unfortunately, not a silver bullet to solve this challenge. Monolayer materials would not only require increased film thickness, but in many cases would also imply a deterioration of the food preserving functionality that is brought by today’s multilayer materials.

Combining techniques
To solve the challenge, Multilayer instead aims to develop a combined solvolytic and chemolytic approach. Through dissolution of one or more of the polymer layers, the mixed film will be fractured into purer feedstocks, with due attention for the solvent’s recoverability and its environmental and health aspects.

In as far as covalent links have been established between the layers, mild splitting reactions are explored to induce layer detachment. For those fractions that remain intractable by selective dissolution, a catalytic upgrading is proposed to produce liquid fractions. All fractions will be characterised in detail at the molecular level, in order to assess their potential for revalorisation.

Specifically, the project will study a number of representative multilayer materials:
  • low-density polyethylene (LDPE) / polyethylene vinyl alcohol (EVOH) / LDPE
  • LDPE / polyamide (PA)
  • polyvinylidene chloride (PVdC) / oriented polypropylene (OPP) / PVdC
As representative tie layers, either polyethylene with grafted maleic anhydride or polyurethane will be considered.

Impact
By developing innovative recycling techniques, Multilayer will help Flemish industries upcycle multilayer materials, use more recycled plastic packaging as feedstock for new plastic products, and contribute to the circularity of carbon in materials.


Project Details

Project type: cSBO in MOT2 Circularity of Carbon in Materials
Approved on: 18/11/2020
Start date: 01/03/2021 (expected duration of 18 months)
Budget: €620.000


Partners


Contact

For more information about this project, please contact Wannes Libbrecht (wlibbrecht@catalisti.be).