New partners in bio-based bottles

10-Feb-2012 - Last updated on 10-Feb-2012 at 14:47 GMT

Related tags Polyethylene terephthalate

Avantium hopes other firms will partner its developments

Coca-Cola is partnering Dutch-based technology firm Avantium in the production of bottles made from an, as yet, uncommercialised bio-based polyester.

But questions remain over how the polymer would sit alongside polyethylene terephthalate (PET) particularly in the recycling stream.

Unlike Coca-Cola's current PET PlantBottle, which has a top limit of 30% plant-derived material, bottles made from polyethylene furanoate (PEF) can be 100% biobased.

With its new 40t a year PEF pilot plant now officially open, Avantium hopes other companies will partner its developments this year. It aims to have a commercial-scale plant running in three to four years time.

Slightly stronger

"Visually, most consumers will not notice any difference from PET," said Avantium md Tom van Aken. "The new material is slightly stronger, and can withstand heat better, up to 10°C higher than PET."

Major benefits include a melt temperature 30°C lower than PET, which enables lower processing parameters, and a significantly better gas barrier. "The oxygen barrier is up to six times better than PET, and three times better for carbon dioxide," van Aken reported.

As with any new material, the scale of production will have a direct bearing on cost and pricing. "We believe PEF will have to compete with petroleum-based PET and, once it is produced on the same scale, we believe the price will be comparable," he said.

While feedstock for PEF could be any type of carbohydrate-rich plant waste, PET production will depend on dwindling oil supplies, he said. Unlike other biopolymer processes, Avantium's is based on catalytic reaction rather than fermentation.

But if PEF is commercialised, what are the implications for the growing PET recycling sector?

Coca-Cola's concerns

"One of Coca-Cola's concerns was whether this material was going to be another PLA," van Aken admitted, referring to the perceived threat to PET recycling posed by polylactide (PLA) contamination.

"With Coca-Cola, we're looking at how much PEF you can mix into the PET recycling stream and still be within specification," he said. "We have good data on lower proportions, but we don't know yet where the cut-off point falls."

Ed Kosior, plastics recycling consultant, said: "The work is based on the concept that the two resins are compatible in the melt, and form solutions when mixed. Avantium will have done the studies, as this question would predicate any consideration of this initiative."