Developing sustainable flexible packaging barrier solutions to support the 2025 sustainability pledges of global brand owners, retailers & convertors

With the rising challenge of tackling global plastic waste, sustainability and the aspiration to move towards a more circular economy are key topics for any business. In Europe, around 40% of the plastic waste originates from plastic packaging and around 20% of the total EU plastic packaging is flexible consumer packaging. Hence, many companies involved in the value chain of packaging materials, ranging from raw material producers, film producers and convertors to brand owners and retailers, have committed to using 100% recyclable, reusable or compostable packaging materials by 2025.

Flexible packaging materials currently are either simple mono-layer, mono-materials (which are 'recycling-ready') or complex multilayer structures (typically not recyclable) for more demanding packaging needs, with each layer conferring certain designed functionalities to the final package. These layers can be polymeric, e.g. film layers and wet-applied coatings/adhesives, or inorganic materials like vacuum deposited barrier layers or aluminium foil.

However, replacing individual layers for more environmentally friendly alternatives is not easy, since properties critical to mechanical or barrier functionalities (which govern shelf life), may be compromised.

The aim of this proposal is to develop sustainable flexible barrier material solutions for food/medical packaging applications as well as associated processes in order to support and achieve the 2025 sustainability ambitions. The proposal thereby consolidates a portfolio of projects united under the umbrella theme of sustainability.

The initial stage will be the development of a novel high-rate silicon oxide (SiOx) deposition process. SiOx, a transparent vacuum deposited barrier layer, has been shown to have good recycling properties and, due to the low thermal impact of the deposition process, it is ideally suited for more heat sensitive substrates targeted in recyclable mono-material (polyolefin-based) and bio-based packaging solutions.

Applications for packaging are limited, though, due to the low deposition rate of the current process.

For the development of recyclable mono-material solutions, the focus will not only lie on SiOx as a barrier layer, but other vacuum deposited coatings such as transparent aluminium oxide and aluminium metal will also be investigated. One of the main challenges when using polyolefin-based polymer substrates are their limiting properties in terms of mechanical rigidity, heat-sensitivity and surface polarity, which challenge the film processing as well as the ability to achieve the barrier properties required to replace existing materials.

Another project will focus on additional barrier enhancement and protection, thus enabling an environmentally friendly and innovative one-step process solution with a reduced carbon footprint. This will be an advancement from current practice, whereby wet enhancement coatings are applied offline during an additional process step.

Further packaging innovations will also include the use of biodegradable/compostable polymer films as well as paper-based substrates in order to produce sustainable barrier materials. Again, the 'new' substrates themselves present the main challenge here in achieving the targeted barrier performance.

Finally, the aim is to also develop innovative sustainable retort solutions, which can be recycled due to their mono-material nature, unlike the current multi-material solutions.

By bringing academic and industry experts together to collaborate on this project under the lead of the Fellow, the outcome of this work will enable more sustainable flexible packaging solutions to be placed onto the market readily noticeable to the consumer, thus advancing closer to a circular economy and a more sustainable packaging future.