Mechanical Recycling, Chemical Recycling, and Bio-based Solutions Explained

From personal care products and cosmetics, to food and detergents, it seems like plastic film has been the go-to material for labels almost since polypropylene (PP) was first developed in Italy back in the middle of the last century.

For decades, brand owners and consumers have trusted PP to be durable, water and heat-resistant, versatile and non-toxic — it does not tear or even smell. So, what’s not to like?

Well, it’s plastic. With a production process that consumes fossil fuel, energy, and water, plus typically gets downcycled not truly recycled, at end-of-life, plastic is seen in sustainability circles as part of the problem with packaging, no longer part of the solution.

Moreover, with the general public waking up to the issue, too, PP in particular is the kind of plastic with a reputation for being difficult to recycle.

In a survey of Amazon customers conducted for Oceana last year, 94% of UK respondents said they were concerned about plastic pollution, 89% said they wanted a plastic-free choice at checkout and more than half (52%) would be prepared to shop elsewhere to get it.

So, whilst retailers might still love the proven performance characteristics, market opinion has changed, moving irrevocably away from plastic in general, explains Mariya Nedelcheva, Product Manager Film Labels, at Avery Dennison:

Over the last 10 years, filmic labels have been enjoying strong growth, taking market share from options such as wet glue paper labels. More recently, however, talk has turned to the question of plastics and sustainability. In the face of rising consumer concern and resistance, therefore, some brand owners are feeling obliged to stop using plastic overall, regardless of the potential recycling CO2 benefits it might have in place of paper alternatives for many applications.

This pull of brand and consumer demand is being complemented by a push from policymakers and regulators — setting 2025 targets for plastic in terms of both recycling and recycled content — with packaging caught in between the two.

Feeling the squeeze, the sector as a whole is under pressure to change, suggests Marco ten Bruggencate, Commercial Vice President for Packaging & Specialty Plastics at DOW EMEA:

The single-use plastic ban was a clear wake-up call for the industry. We need to ensure that going forward there is a commitment, not just from the producers of plastic, but the whole value chain and all stakeholders, to make certain it is not only recyclable, but actually recycled. For that to become a reality, we need to start looking at plastic waste from a value perspective, as raw material. There is movement on this, but we need to maintain and build momentum.

So, how can packaging rethink its offering and innovate to provide both eco-design professionals and end-users with the best of both worlds — the same functionality, but different sustainability?

Contrary to popular perception, the most environmentally-friendly choice would not be moving away from plastic altogether, but simply changing from virgin to sustainably sourced material.

There are three main options available, and the future of packaging will involve combining them all: mechanical recycling, chemical recycling and bio-based solutions. However, no one approach is enough on its own; success is in the mix.

Mechanical recycling: Cleaning the collection stream

In principle, mechanical recycling might seem to offer the most efficient and economical option — you simply have to collect the waste plastic, grind, wash and remelt it. It has a lower CO₂ impact and potential to be lower cost than chemical recycling. In practice, however, the process often falls at the first hurdle, with collection and quality a concern, explains Ms Nedelcheva:

At present, in Europe, the collection and sorting streams for post-consumer PP waste are typically not pure enough to guarantee the quality of recyclate required to match and substitute for virgin material in labels. Moreover, without food approval, its end-use applications will be limited.

So, given a shortage of supply, it is currently hard to achieve recycled content ratios greater than 30% even with post-industrial recyclate. However, the sustainability credentials of mechanically recycled material are better than those of conventional plastic and the expectation is for quality to improve over time.

Chemical recycling: Pioneering a circular economy

Chemical recycling is perhaps the most intellectually satisfying solution, in that the idea of being able to break a polymer back down into its basic components and start again ensures purity of the recycled material and thereby food approval. Another benefit is that it enables high clarity of the recycled polypropylene (rPP) needed for clear labels.

Not surprisingly, the investment and packaging communities are expressing strong interest in the prospects for this process. However, chemical recycling is so new that industrial production facilities are not yet in place to provide the necessary economies of scale.

Furthermore, the assessment methodology used is based on a ‘mass-balance’ approach, which involves tracking and tracing individual material types and volumes within a complex system encompassing a mix of fossil fuel, renewable and recycled elements.

So, at present, with business effectively moving faster than the authorities, the material is still to be recognised officially by the EU as recycled. There is also additional cost for the full value chain brought by an audit pass required under the International Sustainability & Carbon Certification system (ISCC).

Looking ahead, whilst current and future demand cannot be fulfilled through chemically recycled PP alone, the increasing demand for rPP from the packaging industry strongly supports the belief that it will soon become a viable option alongside mechanically recycled PP.

Accordingly, with its successful pilot programme undertaken last year for rPP, Avery Dennison is in the vanguard of innovation in the chemical space and ready to launch a food-approved sustainable material, says Ms Nedelcheva:

We are leading the segment with the development of this groundbreaking material. The challenge ahead will be for suppliers to produce in such volumes to meet the needs of global brand owners. With early adopters like Unilever on board, the future is exciting for chemical recycling.

Bio-based solutions: Cutting carbon with plant power

Producing sustainable packaging from a renewable resource, rather than fossil fuels, is where bio-based solutions might claim the advantage over chemical recycling, which employs energy-intensive pyrolysis — a high-temperature method of treating organic materials in an oxygen-free environment.

Bio-based plastics use renewable biomass and agricultural byproducts in place of petroleum. For its innovative bio-based range, Avery Dennison is utilising tall oil, a residue of pulp production.

For customers keen to cut carbon, therefore, plant power represents an attractive and readily available option. Unhelpfully, however, the term ‘bio’ is often used relatively loosely to refer to a range of agricultural-based purposes and products — especially in the case of food applications — rather than strictly in reference to raw material components of bioplastic packaging. This wider association can leave consumers confused about material properties and even, for instance, lead them to expect packaging to be fully biodegradable when the reality is quite different.

Going forward, bio needs to establish an identity in its own right — one that helps determine appropriate application, usage and, ultimately, disposal. In the plastic drinks bottle market, support for compostable and plant-based solutions from giants like Carlsberg and Coca Cola is helping to drive the bio agenda forward in the wider community, boosting awareness and understanding.

Innovate and invest: Forging a future on all fronts

Ultimately, the industry still has work to do to, and some way to go, concludes Ms Nedelcheva:

We have answers to the plastic challenge; but no single one of them will prove perfect in every scenario — there is no ‘one-size-fits-all’ solution. Reducing the carbon footprint of packaging should be case-specific: evaluating the impact of each particular package and its application. As the technologies advance and markets mature, sustainability will get easier, cheaper, faster and better. However, for that to happen, first we must innovate and invest; and we must do so on all three fronts at once: the future package and label would likely include a mix of mechanical, chemical and bio-based, together.

While every care has been taken to ensure the information, charts, diagrams and illustrations in this article are correct at the time of writing, it is possible that laws and regulations, markets and applications, technology, specifications, or terminology may change at any time, or that Avery Dennison’s research or interpretation may not be regarded as the latest accepted guidance in some parts of the labels or package printing industry.

Avery Dennison therefore cannot accept responsibility for any errors of interpretation or for any actions, decisions or practices that readers may take based on the content and would advise that the latest industry supplier specifications, standards, legislation, regulations, performance guidelines, practices and methodology should always be sought individually before any decision is made.

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Mechanical Recycling, Chemical Recycling, and Bio-based Solutions Explained

Mechanical recycling: Cleaning the collection stream

Chemical recycling: Pioneering a circular economy

Bio-based solutions: Cutting carbon with plant power

Innovate and invest: Forging a future on all fronts