Are all degradable plastics the same?
- No. There are two distinct sets of materials involved in the degradable question.
One set of degradable plastics are materials such as PLA (Polylactic Acid) that are unique plastics for which biological degradation potential is part of the nature of the plastic.
The second set is materials of the standard #1 PET, #2 HDPE, #4 LDPE, #5 PP and #6 PS with special degradable additives included. The mechanisms for degradation vary with additive type.
Are degradable plastics recyclable with standard PET or HDPE?
- No. Materials such as PLA and PET or HDPE need to be kept separate from one another. Each contaminates the other in the recycling stream. The unique plastics that happen to be degradable should be collected so as to not interfere with current PET, HDPE, PP and PS container recycling. Kept clean and dry, those unique plastics could be recycled successfully as themselves.
Will degradable bottles break down in a landfill?
- Probably not. Some need a high-heat commercial composting operation to break down into single molecule level material. Some degradable additives are specifically stated not to work in landfills. Other additives are claimed to work only after years in the landfill.
But some companies producing degradable additives for plastics claim that they are recyclable in today's collection methods.
- According to Steve Alexander, President of APR, "These claims of recyclability are unfounded, untested, and possibly misleading as outlined by the Federal Trade Commission's Green Guide. No third party testing data has confirmed these statements of recyclability. We urge companies claiming recyclability to share such supporting data with the recycling community."
Why can't bottles with degradable additives be recycled with standard plastic?
- The additives change the expectations for a plastic's future function. Bottles with degradable additives can be ground and melted like another bottle, but with reduced quality and service life expectations.
"The facts are very clear," reports Dave Cornell, the Technical Consultant to APR. "The degradable additive concept effectively renders the product using the additive non-recyclable. Many recycled plastics are used to make durable goods. Failure of these next-use products, such as carpets or piping, could range from distressing to tragic."
APR has seen data which demonstrates no harm done during or after the recycling process. Yet these data are insufficient to justify the claim of recycling compatibility. Service life of durable products made of plastics with the additives present must be confirmed to be not shortened. With the variety of durable end uses recycled plastics are used for, the idea of degrading material runs counter to value creation and good stewardship.
What do you mean reduced quality?
- Consider this scenario: A bottle with degradable additives makes it through the recycling collection stream and ends up in a bale of crushed PET bottles. The bale sits outside for a few weeks, and then goes through the normal grinding, washing, and pelletizing process of recycling. The recycled PET plastic is then made into strapping that holds bricks on a pallet. The pallet is stored outside for many months because bricks are insensitive to weather. Then the pallet is placed on the back of a truck heading down the highway. That's a lot of time, weather, and heat that could potentially trigger the degradable qualities of the plastic with additives present and cause that strapping to fail. The consequences could be very serious.
Are bio-based plastics, PLA, and degradable plastics all the same thing?
- No. PLA and other bio-based plastics are made from plant materials, often corn. Not all bio-based plastics are degradable. Some petroleum-based plastics can biodegrade. Degradable additives are claimed to work in many resins. A degraded material is an opportunity lost to reuse a valuable resource.
Won’t degradable additives in plastics help the environment?
It is hard to see how that can be. Fragmenting plastics such as by oxo-degradable additives has few if any benefits and many potential problems. Degrading plastics to methane may sound good, but the capture rate of methane in landfills is such that the biodegradable additives will increase greenhouse gas emissions.
Degradable additives are claimed to work in many resins. Testing does not confirm the claims. A degraded material is an opportunity lost to reuse a valuable resource by recycling. A degraded reputation is also a loss of resource.
But isn't it a good idea to look for non-petroleum plastic products?
- Consider the comparison of polyethylene sourced from petroleum and from bio-sources. On September 11, 2009 Resource Recycling Magazine reported: New research from Germany is adding fuel to the conventional versus biodegradable plastic resin bottle. The Institute for Energy and Environmental Research (IFEU) has released the results of a new study, comparing the environmental impact of traditional polyethylene bags and their biodegradable counterparts available in France and Germany.
After taking into account the raw material production process, transportation factors, and recyclability, the study concluded that PE bags are less damaging to the environment than biodegradable bags. Furthermore, IFEU researchers concluded that bags made from recycled material have the smallest environmental impact.
This is all confusing. What is APR doing to help make the issue easier for recycling coordinators?
- APR has devoted considerable time and energy to produce guidelines and testing protocols to determine if a material meets or exceeds standards for recyclability. Click here to view the APR Design® Guide for Plastics Recyclability. APR is working with producers of plastics to ensure recyclability because we are dedicated to keeping the stream of recyclables clean and valuable. This applies to all materials.
What should I do?
- Ask producers of bio-degradable and oxy-degradable plastics additives to prove that their material does what it claims and is safe to recycle. Ask for proof that carpets and geotextiles from recycled PET and highway culvert pipes from recycled HDPE will have their full expected service life if the degradable additives are present in the plastic. Ask if the appropriate APR test protocols have been met. If you are part of a university or industry setting where you can control purchases, work with recyclers to be sure that a material is recyclable before it is introduced for sale in your facility. Talk to your markets to be sure you know what they want and do not want in the bales of postconsumer plastics.