Plastic recyclers on Dec. 22 issued a set of voluntary testing protocols that materials suppliers and blow molders can use to evaluate the effect of degradable additives used in PET water bottles on the recycling stream.

The Washington-based Association of Postconsumer Plastic Recyclers is concerned that the additives, which help PET to degrade into small fragments and/or methane and carbon dioxide, can have a negative impact on the quality of recycled PET.

Companies selling bottles with degradable additives market them as recyclable, and also argue that they provide an alternative to recycling. The recycling rate for PET bottles is roughly 27 percent, so more than 73 percent of PET bottles end up as litter, in landfills or as marine debris.

But APR contends that the use of degradable additives in PET water bottles is not the best environmental approach because it prevents repeated use of the PET polymer.

“APR is concerned about the impact of such additives on the recycling process,” said Scott Saunders, general manager of KW Plastics in Troy, Alabama, and chairman of Washington-based APR. APR members provide more than 90 percent of the post-consumer plastic reclamation capacity in North America.

“Degradable additives that weaken products or shorten the useful life of plastics would have a strongly negative impact on post-consumer plastics recycling,” said Dave Cornell, technical director of APR.

“Our understanding of the lifecycle implications is that repeated use of molecules through recycling leads to less of an environmental burden than single use of molecules, more efficient use of natural resources and complements overall sustainability efforts,” Cornell said.

Suppliers of degradable PET bottles have not provided test data to APR to verify claims about recyclability.

“We are very concerned that these claims are being made with no test results to justify such claims,” said Steve Alexander, APR’s executive director. “How can anyone make such a claim when no one has provided any data to show that these additives do not affect the next use of a reclaimed plastic? Many second life applications are in products designed to last 30 years or so, such as strapping, fiber and pipe.”

Companies that use the additives have asked APR for a test that they can use to justify recyclability claims, Alexander said.

The APR Degradable Additives and PET Recycling Technical Compatibility Testing guidance document offers a method to examine the impacts of degradable additives on PET recyclability.

The testing is intended to be useful with several concessions to practicality. For instance, testing is recommended to be conducted on fibers rather than on carpeting. The service life of carpets is proposed to be simulated through demonstration of effects with long-term aging of fibers.

In addition, in lieu of real-time aging, the guidance documents says additive manufacturers should use accelerated aging methods to validate their claims that the shelf life of products will not be affected by the additives.

Because of the consequences of premature product failure, APR recommends use of its testing protocol for products that are likely to be recycled.

“The APR voluntary testing protocol for the effect of degradable additives on recyclable PET bottles provides a framework for substantiating recyclability claims,” Alexander said. “APR encourages brand owners to use the protocol to substantiate claims.”

There are at least three firms supplying PET additives and at least five companies with plan to market the bottles, including Planet Green Bottle Corp. of Vancouver, British Columbia, and Phoenix-based Enso Bottles LLC.

The Aquamantra Enso bottles used by Los Angeles-based Aquamantra for its natural spring water line have been sold at some Whole Foods Market stores since July, and at all 262 Albertsons supermarkets in California since September. Enso uses the EcoPure biodegradable additive made by Bio-Tec Environmental LLC in Albuquerque.

Planet Green has a prototype bottle that is not commercially available. Its bottles will use the Reverte additive from Wells Plastic Ltd. in Stone, England.

Enso said EcoPure is designed to degrade the PET bottle within one to five years in a landfill. Planet Green said its additive will break down PET over 10-20 years. Both firms claim the additives will not adversely affect the recycling stream or the shelf life of products made from recycled resins.

“We don’t think they can justify and substantiate the claims,” Alexander said. “Everyone has jumped on this as a panacea, but we haven’t seen any test data to justify their claims that these additives will not negatively impact the recycling stream or the next product made from that resin.”