PLANT

Biodegradable PET joins the green stream


September 16, 2009
by Noelle Stapinsky

Degradable plastics have worked nicely in certain applications (such as agricultural mulch films, medical sutures and compostable bags) that correspond with municipal composting operations. Yet the global media spotlight is on the amount of plastic ending up in landfills, rivers and floating in oceans. A dramatic and troubling visual of this dilemma is the “Garbage Island” video, depicting a floating mass twice the size of Texas made up of decades’ worth of discarded plastic swirling in an ocean jet stream between California and Hawaii.

The floating plastic photo-degrades to the molecular level allowing polymers to enter the food chain. Biodegradable plastic breaks down and is harmlessly absorbed into the environment.

Plant Green Bottle Corp. has introduced an additive that it claims will biodegrade plastic bottles dumped in landfills within 10 to 20 years.
PHOTO: HYENA

Planet Green Bottle Corp. (PGBC), based in Mississauga, Ont., introduced an additive that it claims will break down polyethylene terephthalate (PET), the plastic used in beverage bottles, within 10 to 20 years.

Patrick Rooney, co-founder and director of PGBC’s corporate development, says public concern over PET bottles is growing. Plastic water bottles, for example, are being banned at municipal facilities and educational institutions.

The additive, branded Reverte, is a pellet-like compound developed by UK-based Wells Plastic Ltd. in partnership with PGBC. It causes PET plastic bottles to oxo-biodegrade, meaning they will breakdown when exposed to UV and oxygen.

Rooney says current PET preforms and bottle manufacturing processes do not have to be altered to use the additive because Reverte represents less than 2% of the polyethylene terphthalate mixture.

Once in bottle form, the products have a two-year shelf life. “We put blockers in the additive so it won’t break down,” says Rooney. “After that the process will only start once it has been exposed to the elements [in landfill or recycling streams].”

PGBC’s website (www.planetgreenbottle.com) illustrates how the plastic product melts into nothing when exposed to UV and oxygen, which begs the question: how will it react in the recycling stream?