The struggle to make sense of bioplastics

While biofuel is understood by all to be derived from a renewable bio-based source, the bioplastic label has been coined by producers of renewable plastics, as well as makers and suppliers of renewable and non-renewable biodegradable plastics and even non-renewable degradable plastics. The result seems to be confusion at every level of the supply chain, not least for the consumer.

Gaelle Janssens, waste prevention and R&D manager with the Belgian recycling organisation FostPlus, quantified this in one key finding from a survey of Belgian consumers, which showed that 21% thought "biodegradable" packaging would simply disappear in the environment.

Biodegradable, along with the terms degradable and bioplastic, has no real legal definition in Europe. Compostability is defined by the EN13432 standard but this applies only to packaging composted in industrial installations. Janssens said its surveys show 73% of Belgian consumers think the compostable label means the pack will degrade in their garden composter.

Perhaps the most interesting finding from FostPlus's surveys of Belgian consumers, according to Janssens, is that they rank renewable sourcing of packaging as a higher priority than compostability. And Belgian consumers may be right to do so. She explained that Belgium has an established infrastructure for incineration of residual waste to capture the energy content; the FostPlus analysis shows this is more environmentally favourable than composting of either PLA (polylactic acid) plastics packaging or products produced in Novamont's starch-based Mater-Bi.

"The key factor is production of energy. The problem with composting is that you get CO2 and water but no energy," she told delegates. "It [composting] is an interesting solution if you have an application for it. But the claim of compostability shouldn't be made to the consumer unless it is the most sustainable option and there is an existing infrastructure."

Compostability is also viewed as a limited waste management option for packaging in the UK, according to Peter Skelton, key account manager in the brands and retail team at WRAP (the UK government funded organisation charged with promoting sustainable waste management).

At present in the UK 25% of local authorities collect food waste for composting, according to Skelton. None allow compostable packaging into the waste stream, aside from the supplied organic collection bags, because of the risk of potential contamination with non-compostable packaging.

"Government and local authorities are focusing on the 6.3 million tonnes of food waste, not the few thousand tonnes of packaging," said Skelton. "We are not seeing the appetite for these [compostable] materials that we did in the past."

Professor Hans-Josef Endres, who is heading up development of a bioplastics technical database at the University of Applied Sciences and Arts in Hanover, also sees composting as a recovery option of somewhat limited use. "Composting only makes sense where it leads to an additional benefit, like waste bags. If it is a package that could be recovered in another way, such as a clear tray, then it is no benefit," Endres told conference delegates.

Endres said he considered the bioplastics sector to be on the cusp of significant change. Today's materials, which he described as second generation bioplastics, have been developed almost exclusively for compostable packaging and the emphasis, he said, has been on degradability over renewability. Third generation bioplastics will drive a shift from degradability to durability, he predicted, and a simultaneous growth in renewable raw material content.

While it is not unusual for recycling authorities and academics to question the place of composting in the hierarchy of waste management, Natureworks environmental affairs manager Erwin Vink added his own call for bioplastics materials producers to stop promoting composting as the sole end-of-life option for its products. The move surprised some delegates as US-based Natureworks is the leading producer of polylactic acid (PLA) bioplastics, which are compostable within industrial installations.

"Quite often today we see bioplastics equalling compostable plastics. We really have to get rid of that impression," said Vink. "We must look for the most sustainable solutions. That will depend on where you are and what materials you are looking at."

Vink said traditional composting is just one of many solutions for the end of life treatment of compostable bioplastics. Potentially more beneficial options could include anearobic digestion - composting with energy recovery - as well as incineration with energy recovery, mechanical recycling and feedstock recycling.

Vink said that end-of-life solutions must also take into account the reality of the marketplace. He pointed out that Natureworks has been using a feedstock recycling technology - which hydrolyses PLA back to lactic acid feedstock - to reprocess off-specification Ingeo polymer at its plant at Blair, in Nebraska in the US.

"We have looked at the energy and environmental costs and it looks very promising - you are avoiding the cost of corn production, milling and fermentation," he said. However, Vink told delegates the technology requires a local source of PLA as shipping lactic acid around the world makes little sense.

Bioplastics producers may have little influence over end-of-life treatment strategies, but they have at least some control over manufacturing eco-profiles and minimising environmental impact has been high on the agenda at UK-based cellulose film producer Innovia Films. The company's global marketing manager for sustainable technologies, Andy Sweetman, told the conference that completion last year of an eight month life cycle assessment (LCA) project had positioned it to further optimise its production processes.

"LCA tells you what your inputs are and, more importantly, where they are so you can start to make improvements," he said.

Armed with the data from the LCA, Sweetman said the company is now moving forward with optimisation of its production processes. "The raw materials we buy in have an impact [on emissions] so we can choose suppliers that improve our LCA," said Sweetman.

The commissioning this year of a new production line at its plant at Wigton in the UK will provide it with a 30% increase in line speed along with a 10% improvement in drying efficiency. The new Natureflex line was initially intended to replace two of its oldest, and hence least efficient, lines. However, growing demand means that one of these may need to be kept in production, he said.

The debate over where and when composting makes sense aside, there was general agreement among speakers that bioplastics will succeed in the plastics market where they bring value. Bioplastics do not outperform or even match traditional packaging polymers in many areas, but they do provide some useful properties in specific applications.

"There has to be a reason for using bioplastics," Stefano Facco, new business development manager at Novamont, said. The company's MaterBi polymer is used quite widely in organic waste collection systems where the compostability of the bag means it does not need to be separated from the organic material for composting. In addition, its water vapour permeability allows moisture to escape and dramatically improves the efficiency of the collection and composting process.

The permeability performance of bioplastics is also being used to good effect by Italian packaging producer CoopBox Europe, which since the beginning of this year has been producing a PLA pack for Italian dairy group Mauri's Gorgonzola cheese that exploits the bioplastic's gas permeability to provide extended shelf life.

Coopbox packaging systems R&D manager Cesare Vannini told delegates that the pack - a thermoformed PLA portion tray sealed with a peelable and reclosable PLA film lid - allows a controlled gas exchange between the inner protective atmosphere and external air to preserve both the colour and the organoleptics of the product for up to 30 days.

Cost remains an issue for potential users of bioplastics, however. University of Hanover data shows that while PLA pricing starts from around €2,000 a tonne, prices range from €3,000 to more than €5,000 a tonne for starch blend and cellulosic bioplastic grades. The newer PHA materials could, at least initially, cost even more.

"How do you persuade a company to go down this route when the costs are so high and they are not that clear about what they can do?" asked Hariharan Ramasubramanian, a plastics and polymer industry analyst with Frost & Sullivan.

Bioplastics market growth is also likely to suffer from the economic downturn, Ramasubramanian said. The falls in oil prices have eased, temporarily at least, some of the pressures on companies to look for non-petrochemical alternative materials. The tightening availability of credit may also mean that some of the bioplastics material and feedstock investments planned for the next few years may yet be put on hold, he warned.