Thanks to China’s ban on waste imports, Theresa May’s environmental action plan and, perhaps most influential of all, the depiction of humanity’s devastating impact on sea life in BBC series Blue Planet, plastic has regained its position as public enemy number one. Our consumption of the material is prominently unsustainable, and all eyes are on the industry to find a feasible alternative.
Paper coatings could be the answer. According to a report by Smithers Pira, paper and paperboard packaging is expected to reach 218 million tonnes by 2022, up from 162 million tonnes in 2012. Meanwhile, the global market for functional and barrier type coatings reached nearly $6bn (£4.3bn) in 2015, with 5% annual growth projected though to 2020, when sales are expected to exceed $7bn.
These coatings are nothing new, per se, but they’ve traditionally struggled to gain traction because of performance issues compared to their plastic counterparts. “There have been a whole load of challenges,” says Mark Hilton, resource efficiency lead at environmental consultancy Eunomia. “Getting the right barrier properties, lightweighting, heat-proofing – the sort of things that plastics are good for. Then there are packing logistics. Once you’ve found a suitable alternative you can’t just move from using a plastic tray that’s formed then and there on the line to a box which may need assembling. The transition away from plastic goes beyond simply finding a replacement.”
Nonetheless, the work going into solving the first part of the puzzle is extensive, and there are multiple products now on the market that mitigate the historical problems presented by plastic alternatives. Metsä Board, for example, has just launched a new eco-barrier paperboard that uses a coating which is bio-based, recyclable and biodegradable. Designed for the food service industry, the paperboard offers grease resistance up to KIT level 5, requires a 50% shorter print machine time for barrier treatment and has already seen success in the field as baguette packaging for Finnish bakery Huovisen Leipomo.
FoodBoard, from MM Karton, is a plastics-alternative that addresses food safety and shelf-life concerns. The coated cartonboard offers the same levels of contamination protection for dried and fast food as plastic equivalents, guarantees freshness for 36 months and is also recyclable and biodegradable. Meanwhile, Dow’s RhoBarr offers impressive grease resistance properties, while Akzo Nobel is working on a composition that can be made from existing plastics waste and won’t affect the compostability of the paper it’s applied to.
Cellulose coatings in particular are helping to drive progress forward. Futamura, which acquired Innovia Films’ cellulose business in July 2016, offers a compostable packaging called NatureFlex, which boasts a high gas barrier and a tailored moisture barrier, plus a wide heat-sealing range and “excellent machinability”, which helps to address some of the logistical issues involved in transitioning away from plastics. Renewable packaging company Stora Enso’s latest development is focused on micro-fibrillated cellulose (MFC), a new quality of cellulose that’s made by passing wood pulp through a milk homogenizer in order to entangle the network of fibres into much smaller fibrils. This creates “more from less”, says sales manager Craig Pearson. “By using MFC, the material offers maximum yield and thus more packaging material per tonne of board. Important properties, such as stiffness and internal strength, are maintained, with less weight.” He adds that the list of end uses is “huge”, and that the firm believes “anything currently made from fossil-based materials can and will soon be made from a tree”.
But herein lies a number of problems in the move away from plastic, which could merely amount to a “knee-jerk reaction” if not considered properly, says Eunomia’s Hilton. “It’s not just about what happens at a piece of packaging’s end of life, it’s about the whole life-cycle impact.” Hilton cites greenhouse gas production figures as an example. “There’s around three tonnes of CO2 equivalent for every tonne of plastic material created, depending on the polymer, compared to around 0.8 or 0.9 tonnes of CO2 for every tonne of cardboard that’s made. Obviously, on the face of it, cardboard is a more sustainable choice since it has a lower carbon impact and is recyclable. But then you have to consider weight. Even with barrier coatings, you’ll need more cardboard in an item of packaging to mimic the functionality of plastic, or to ensure speed on the production line, so you might end up using two or three times the weight, which then offsets the benefit you’d get in the first place from using card.”
Plastics alternatives could also inadvertently create more waste, Hilton says, nodding towards the growing mountain of food waste the UK creates every year. Coated paper packaging may be recyclable and have renewable origins, but compromises on shelf life could result in more food being thrown away. “From a life-cycle perspective, that’s one of the worst things that could happen. There are a host of trade-offs to be considered and we need to take a careful, science-based approach to plastics alternatives.”
He adds that undertaking effective life cycle analysis on these barrier coatings can be all the more difficult because of commercial sensitivity. “Packaging manufacturers are riding the wave of this renewed interest in plastics alternatives and don’t want to give too much away, so many don’t want to say what’s actually in their material. They’ll just say it’s ‘ethylene copolymer’, or be even more vague and describe it simply as a ‘biodegradable barrier film’. There’s a lot of commercial confidentiality, and so the research and analysis that needs to be done isn’t necessarily being done.”
Another issue, again beyond the packaging itself, is the management of coated material once it’s in the waste stream. “Take those cups from Costa and Starbucks, for example,” says Neil Osment, managing director of NOA Prism. “They’re a great example of how a carton material and coating work really well, but getting them to the right place at the end of their life is a problem.” Indeed, there are just three recycling facilities in the UK capable of efficiently processing these kinds of cups, one of which is Cumbria-based James Cropper. The fibre-recovery plant can process up to 500 million cups annually, but since it began accepting the material in September 2017 has processed just 10 million. “There’s some great work happening with paper coating,” says Osment, “but there needs to be a collection system for these materials, otherwise we’ll just end up with a sea full of paper cups instead.”
Hilton agrees, noting that the success of paper coating in a sustainability context largely depends on the recycling sector finding ways to manage it. “If something looks like what it’s not, it’ll cause problems in the waste management system. Many facilities aren’t able to process plastics-coated paper and card, so they may end up mistakenly rejecting items that are in fact covered in water-soluble or biodegradable coatings, which defeats the purpose of them in the first place,” he says.
However, as David Morris, technical director at Pulse Printing Products, says: “Even if it doesn’t end up in the right waste stream, cardboard is more easily destroyed than plastic – it’s the longevity of plastic which is the major emphasis at the moment.” Pulse’s current focus is coatings with MVTR (moisture vapour transmission rate) properties which, he says, works very well with a number of products – in particular tea bags – and Morris believes that paper coatings are now at a standard that makes them a suitable replacement for many products. “Whether it’s offering moisture resistance or preventing gas transference, there are certainly coated paper board options available that can replace plastic packaging as we know it right now. But plastic has become the problem it has for a reason: it offers all the right properties, it’s cheap – cheaper than paper and card treated with coatings and barriers – and everyone is used to it. The issue isn’t so much in finding a suitable alternative as it is in changing attitudes.”
A host of companies, from Coca-Cola to L’Oréal, have made pledges to reduce their plastics packaging in the coming years. Others, such as The Co-operative and Marks & Spencer, have already made significant strides in tackling the issue. “People want to see less plastic,” says Hilton, “and the industry is listening. By economies of scale, the alternatives will become more cost-effective in time – the technology is already there. However, just because coated paper occupies a more environmentally friendly position than plastics doesn’t make it inherently ‘green’. There are a lot of factors to consider beyond the packaging’s properties. But, with the right research and development, it does have the potential to address what has become a serious waste issue.”