Innovation and scaling in flexible bio-packaging are badly needed
2022 marked a historic year for action on plastic pollution. In March, almost 200 countries negotiated towards a legally binding UN treaty to cut plastic. Mammoth brands including Coca-Cola, PepsiCo, Unilever and Nestle backed the measures.
Today, we have the technologies at hand to meet grand goals on petrochemical plastics reduction. There are bio-based alternatives for many synthetic plastics, offering robust performance criteria and a lower fossil footprint. Circular solutions from businesses are also mounting.
Yet one plastic remains the bête noir of corporate sustainability targets: flexible packaging. These are the thin plastic layers we encounter as clingfilm, bin-bags, food packaging seals, sachets, and wrapping – applications that are overwhelmingly single-use.
These materials are so problematic that the Ellen MacArthur Foundation has dedicated an entire research programme investigating ways to draw-down their use. One of the foundation’s many reports on the material warned in no uncertain terms that “unless simultaneous, unprecedented efforts across packaging design, infrastructure, and policy are begun immediately – efforts that push far beyond the level of activity we are currently seeing – the circulation of flexible packaging in practice and at scale is unlikely to happen”.
Why Are Flexibles Such A Problem?
Several factors combine to make synthetic flexibles a particularly urgent sustainability target. First, fossil fuel-based flexible plastics are notoriously hard to recycle. There is no way round the fact that, at each iteration, there is a significant loss in mass, quality, or both.
Second, hard-to-recycle flexibles are used in almost every consumer sector. On the one hand, many applications are low hanging fruit from a sustainability perspective – think over-packaged fruit and vegetables.
The Ellen MacArthur Foundation estimates around 5-10% of the flexibles market today could be outright eliminated. Yet this is not so easy when it comes to certain food or medical products. Here, the materials can offer a disposable, water-repellent and anti-microbial barrier that supports consumer safety and hygiene standards.
Its resistance to recycling and its unique functionalities make eliminating or re-circulating extremely problematic for the majority of flexibles in use today. The other option is to switch to new compostable biomaterials with similar flexibility and strength. The Ellen MacArthur Foundation says that flexibles are the plastics category where substitution to compostable materials, rather than recycling or elimination, is the most relevant draw-down strategy.
Nonetheless, this route is also challenging. Synthetic flexibles are difficult to replicate using organic renewables on certain performance criteria, although the needle is slowly shifting on this front.
Despite these difficulties, many start-ups around the world have taken off to specialise in bio-based flexible packaging.
Edible flexible coating
Edible bio-flexible packaging has been all the rage in recent years, with some startups in the space receiving significant funding and media attention. Most use low-carbon seaweed biomass as their feedstock. These films are generally made up of some combination in algal protein, lipids, or carbohydrates.
London-based FlexSea is one of the latest entrants to the edible flexibles market, founded in 2020. It offers a ‘truly compostable biopolymer’ from seaweed and other biomass to “seamlessly” replace flexible plastic packaging. Its compostable appellation is crucial selling point because not all plastics made from bio-materials are degradable. Many others are but can only be broken down into environmentally benign compounds at specially equipped industrial facilities.
FlexSea’s products are home-compostable, meaning that it bio-degrades quickly in the natural environment or compost bin within weeks. Naturally, this means that it also dissolves safely in the ordinary washing cycle at recycling facilities.
London-based NotPla, founded 2014, also offer water-soluble single use sachet for home and personal care applications. These products are also easily bio-degradable, even under natural conditions, and do not contaminate conventional plastic or paper recycling streams.
Mori, a Japanese edible coating from natural silk, also ticks the compostability box. Its other feature is that it protects food from spoiling by limiting microbial growth. This is relatively uncommon in the edible flexibles market, with petrochemical flexibles generally offering a superior barrier against microbial incursions. Mori also limits oxidation, providing hygiene and food protection features that incentivises the use of petrochmiecal plastic food packaging.
The Next Phase Of Biomaterial Flexibles
These water-soluble flexibles offer a vital part of the plastics reduction toolkit. However, edibles cannot replace all the petrochemical equivalents that remain once unnecessary packaging has been eliminated.
While edible films protect food from oxygen at medium to low humidity levels, these water-soluble materials obviously offer poorer protection against higher moisture in the external environment. They also tend to have relatively fewer antimicrobial properties. Chitosan is a major exception to this rule but making functional flexibles with this material has proved challenging.
Solving the limitations of compostable bio-packaging falls to the field of nanotechnology, which has been exploring a new material type called bionanocomposites. Bio nanocomposites represent the very leading edge of innovations relevant for improving sustainable packaging performance.
Industry and academia have been familiar with the packaging potential of organic materials for years but nanotechnology offers an important tool in enhancing these maturing innovations. It opens the possibility of retaining their unique bio-degradable and non-toxic features while elevating their mechanical properties to make them fit for further applications.
Bionanocomposites are emerging materials that combine two components: the biopolymer (this could be made from the proteins and carbohydrates of algal biomass, as in many of the edible flexibles) and then nanoscale strucutres of silicates or carbon. Depending on the concentration. the latter component reinforces the overall material or alters its chemical properties. They can make biomaterial packaging antimicrobial, antioxidant, or even make it into a biosensor that detects chemical changes in the environment and adapts its features accordingly.
Bionanopolys is an EU Horizon project currently working on setting up pilot manufacturing plants for bionanocomposites. It is one of the very few organisations attempting to pull this new material class out of the lab and into industry. In the meantime, taking petrochemical flexibles out of circulation may require more pragmatic measures.
Elimination Is Still Key
The Ellen McArthur Foundation estimates that switching to compostables is appropriate for up to 20 percent of the total business-to-consumer flexible market by 2040.
Elimination, however, should always remain the first port of call. This is simply due to the huge global volumes that make up the class of flexibles. Bio-based alternatives, despite their many sustainability advantages, also consume energy and resources to manufacture.
The vegan cosmetics brand Lush holds pointers for companies looking to eliminate flexibles. It has found creative ways of eliminating seemingly essential rigid packaging for some personal care items, stripping one product line of packaging entirely while embedding functions ordinarily provided by an outer layer into the item itself.
In Lush’s package-free range, products like shampoos and foundation come as an easily transportable soap-blocks that melt on contact with water or body heat. Ingredient information can be gleaned through a quick phone scan.
Of course, such strategies are not always applicable food items but indicates that innovating in product materials could be an elegant solution to recalcitrant flexibles.
Over recent years, there has grown a belief that seaweed and microalgae offers a uniquely cost-free virgin feedstock. Some media coverage around algae products would even seem to imply that this crop is so low impact that it could underpin a product chain so eco-friendly that it dissolves the need for recycling or upcycling altogether.
Yet the bio-sector needs to be wary of such claims. Throwaway compostable bio-alternatives will still draw on virgin resources, which always bear an ecological cost: in their case, bio-based rather than petrochemical. In terms of seaweed, the cost could mean tracts of marine ecosystems given over to offshore kelp farms or the energy and nutrients required to grow seaweed at scale in aquaculture facilities on land.
Where flexible materials cannot be eliminated altogether, the renewable alternatives we replace them with should be made from waste feedstock. Alternatively, these products should offer further uses after the end of one product life. Ideally, it should do both.
While throwing away a bio-degradable food package may not have the toxic consequences that come with petrochemical litter, what it does do is dissipate the nutrients inside its materials, an essential input into the agricultural supply chain.
Dissipation of energy and nutrients in bio-flexibles is far more likely to happen with bio-packaging for things like consumer electronics or crisp packets rather than items that people automatically classify as compostable – tea bags, for example.
Bio-based packaging containing electronics or confectionary would tend to find themselves in recycling facilities than bio-waste facilities that create high quality compost from organic substances.
Organic recycling faces the same problems as recycling for non-organic materials. Apart from miscategorisation by consumers, recycling collection and processing infrastructures are in their infancy in many parts of the world. As a result, only 13% of organic waste is collected and treated in proper recycling facilities, despite the fact that it makes up nearly half of all municipal solid waste generated globally.
To maximise gains from bio-alternatives, there must be a solid infrastructure for processing, collecting and returning nutrients to the soil and limiting wastage of the energy that went into growing and manufacturing these materials.
There is another easily overlooked aspect of the flexibles problem. Flexible materials cannot be looked at in isolation from all other components that go into a packaging. This includes sticky labels, adhesives, and dyes. Otherwise, end products harbouring non-compostable parts will contaminate the circular upcycling chain or at least make processing facilities less efficient than they could be.
Flexible bioplastics startups must therefore forge business partnerships with complementary bio-segments that are equally critical in packaging design. This includes the burgeoning bio-based pigments sector that is generating eco-friendly alternatives to petrochemical dyes and ink – easily overlooked consumer design details.