US water brand adopts “biodegradable” PET

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Californian mineral water bottler Aquamantra has adopted Eco-Pure modified PET resin for its bottles, which is claimed to provide biodegradability without compromising conventional mechanical recycling activities.

Aquamantra launched the Eco-Pure technology, which is marketed by US company Enso Bottles, on its Premium bottled water lines sold through Californian retail chain Whole Foods Markets, this month. It is using preforms produced by Enso Bottles’ partner Resilux.

Enso Bottles president and joint founder Danny Clark told European Plastics News that Aquamantra is one of the first companies to commercialise the Eco-Pure material. Native Waters of Massachussetts is also using the resin, while it is currently being evaluated by Tushar Mountain Bottling in Utah and Calloway Blue Spring Water in Georgia.

Clark says that the Eco-Pure resin is a modified PET resin; it does not use oxo-degradable technologies and it is designed to complement, rather than interfere, with mechanical bottle recycling processes.

“We are pretty familiar with the oxo products. There are probably some good applications for them but we do not think fragmentation [of the plastic bottle] is good or having the metals and the antioxidants,” he said.

He makes great efforts to distinguish the Eco-Pure biodegradation mechanism from resins such as PLA, which meets the 180-day complete biodegradation requirement of ASTM 6400 in compostable bottle applications.

“Eco-Pure is not a compostable product in either a back yard or in a commercial composter,” he told European Plastics News.

While Clark is clear that the resin is not compostable, that message does not appear to have got through to his customers; both Native Waters and Aquamantra make the claim on their web sites.

The Eco-Pure resin used by ENSO Bottles is a compound of 99% standard PET resin compounded with an organic additive at 1%, which is claimed to make the PET susceptible to microbial attack under both aerobic and anaerobic conditions.

“The key thing is that the additive doesn’t degrade. There’s a lot of confusion about this because of the oxo-degradables. It’s just a food source – nothing happens to it until it’s put into a microbial environment,” he said.

Clark claims that the presence of the additive enables the microbes to penetrate the PET quickly, even in landfill conditions. As the microbes consume the additive they produce acids, he claims, which swells the PET resin matrix and allows the polymer to be consumed.

Total breakdown of Eco-Pure bottles in an anaerobic landfill environment can be achieved in between one and five years, the company claims.

Clark is confident that, unlike both PLA and oxo-degradable PET alternatives, bottles produced from the Eco-Pure material do not have the potential to harm the US PET recycling industry.

“Our first focus is recycling and we make it clear that recycling is the best route for bottles to go. But in the US we have a way to go – for every one bottle recycled three go into landfill,” he says.

“We wanted a solution that did not compromise recycling,” claims Clark. “When Enso bottles are recycled they have the same useful life as other durable plastics. There is no cloudiness, there is no yellowing and from a chemistry perspective there are no second life problems.

Enso claims recycled Eco-Pure resin has successfully completed third-party lab testing for haze, transmission, intrinsic viscosity and acetaldehyde, as well as passing visual checks for black specks and gels. All have met industry specifications.

In addition, Clark says more than a dozen processors have determined no detrimental effect on their product in strapping and sheet applications; the resin has not been examined in bottle-to-bottle recycling but he says the company has offered to cooperate with the APR on trials.

Clark says the cost of implementing the Eco-Pure additive technology depends on whether it is pre-compounded into the resin or added at the moulding machine. He estimates an additional cost of around 2% in conventional water bottle applications.

The technology behind Eco-Pure is developed by Bio-Tec Environmental of Alberquerque, New Mexico. The additive is FDA approved.

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