As my previous post explained, our degradable bags (contact us to order them) use an additive that allows them to degrade by breaking down their chemical structure. Oxidation through heat or ultraviolet light leads to this degradation, rather than bacteria and fungi that are found in typical composting efforts. Thus, our bags are oxo-degradeable. The test results linked in my prior post show the results of accelerated UV decomposition.
Ray Loflin, of Willow Ridge Plastics offered further information:
“Oxo-biodegradable plastics are designed to biodegrade in ANY environment. It can’t be guaranteed where a customer will dispose of waste, therefore we have a technology that is an insurance policy on covering any environment it goes to. That includes, municipal waste, recycling centers, or even litter (accidental or otherwise).
“The important thing to note is that ASTM D6400 and D6868 is an industrial composting standard. That is not a home composting standard because there is no such thing as a home composting standard. Industrial composters are massive composting facilities that exert lots of energy and water to keep the material in ideal conditions for slow incineration, which is what is happening to the material. It should also be noted that D6400 is under critical review at ASTM because it does not meet the needs of industrial composters nation wide, who have begun to turn away ‘industrial compostable’ products. They take up to 180 days to meet the requirements of the standard, which is 90 days longer than most composters want it to last.
“On top of that, if a product approved under BPI guide lines, or ASTM D6400 guide lines, and ISN’T disposed of in an industrial composter, then it remains as waste and nothing will change that. Therefore, it’s an effective technology in only very specific conditions.
“However, an oxo-biodegradable plastic will both degrade and BIODEGRADE in a home composter, unlike other technologies. Because the technology doesn’t require water and high heat to perform, it means there is lots of flexibility.
“Unicorn Bags will have a hard time getting on the BPI list because the Biodegradable Plastics Institute is solely run by PLA, Starch, and composting companies. They do not let technologies like oxo-biodegradables into their ‘club’ since they don’t use one of their technologies. None of our products will pass composability testing because those tests were designed ONLY for hydro biodegradable resins (PLA, starch, etc). It’s essentially saying you want to judge a motorcycle on safety standards designed for a car. ASTM D6954 is the standard guideline for testing Oxo-biodegradable materials.”
This document from the Oxo-Biodegradable Plastics Foundation explains more about this material.
Is this product going to leach chemicals into my lovely compost? Assuming i may be composting 1,000 or so of these bags annually.
Hi Ben, every composting process is unique and there are no black and white answers in this topic. I will refer to the ASTM D6400 and D6868 industrial composting standards for more information on how it relates to your specific use case. The additives used are in the corn starch “family” and with the correct temperature, sun exposure, and oxygen conditions it should not harm your compost pile.
What additive is used to make the polypropylene oxo-degradable?
The additive is proprietary to the manufacturer but is predominantly in the Corn Starch “family”.
Hi Lou, after reading the above statement i am trying to understand if by buying these bags I can then compost them at home in direct sunlight in a special pile. Is that possible? Thanks
Hi Stephanie – yes that is possible. Although no guarantees as results are based on temperature, light, and oxygen. Your use case sounds plausible.
When the bags breakdown, what is left? Is it just a pile of microplastics? Or does it breakdown to something more primitive?