France-based biochemistry company Carbios has, together with Solvay, demonstrated that its PET depolymerisation recycling process is also suitable for barrier film.
Tests conducted by the two companies have illustrated that Carbios’ enzymatic technology works with multi-layer PET films coated with Solvay’s Diofan PVDC high-barrier polymer, yielding fully depolymerised PET and an intact PVDC layer as a result. PVDC, in other words, does not jeopardise the PET depolymerisation process.
The collaboration builds upon the results of an earlier proof of concept by Solvay which has confirmed that waste from packaging or other applications using bi-oriented PVDC multi-layer film could be efficiently recycled without compromising the barrier performance of the polymer.
OEMs and brand owners, who are under tremendous pressure to increase the sustainability of their products, will welcome the news. Solvay’s Diofan and Ixan PVDC high-barrier polymers are today commonly used for food packaging applications, including fresh and processed meat, fish, poultry and cheese, as they provide a barrier against the permeation of both water vapour and oxygen as well as protect against odours and loss of aroma or flavour.
“While PVDC has long been used for coating flexible PET films e.g. in food packaging, where it delivers impressive barrier properties, these multi-layer structures have been challenged regarding their recyclability,” said Guruprasad Sivakumar, head of marketing for Consumer, Healthcare and Environment at Solvay.
“This is where Carbios’ unique recycling technology comes as a real game-changer. By providing a feasible and sustainable end-of-life management solution, it can help the industry close the loop on PVDC-coated PET films and extend the value proposition of our high-barrier specialty polymers to further markets, such as the packaging of pharmaceutical products.”
Carbios’ patented recycling process uses specific enzymes to break PET molecules down to their constituent monomers and overcomes the limitations of other recycling processes, explained Alain Marty, Chief Scientific Officer at Carbios.
“Conventional thermo-mechanical routes require clean-mono-material grade waste, and high-heat chemical or pyrolytic recycling cannot be used to regain the material value still present in many end-of-life applications,” he added.
The process developed by Carbios requires only moderate temperatures, which is ideal in the presence of PVDC, and is suitable for recycling both post-industrial and post-consumer waste. The resulting monomers can be purified and reused to produce new, virgin-quality PET polymer.