On what basis are resin identification codes given? Is it for the easier and more efficient recyclability of PET that it got the code 1?
- Filed in:
- Flexible packaging,
- Recycling,
- Food
I would like to know on what basis are the resin identification codes given?
Is it based on the easier recyclabilty of a polymer, i.e as PET is easier to recycle than other polymers such as HDPE, LDPE, PP, PVC , etc.
And which polymer has the smallest biological footprint as everyone tries to market PET, PP, PE equally and they are all very efficient.
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Recyclability not a factor in ID Codes
Stephanie Baker
Great question and one that comes up often. Unfortunately, the SPI resin codes found on the bottom of plastic containers have nothing to do with the recyclability of the package, at least there was never an intention for them to.
The ID codes are used to simply identify the material that was used in the manufacturing of the package. I often like to say that the ID codes tell the history of the package, not the future.
As recycling became more mainstream, recycling coordinators often educated their public to look at the numbers when selecting what could be included in their bin "1s and 2s only". Today, more programs are referring to bottle shape and the size of the mouth of the container rather than relying simply on numbers.
As a recycler, we have found there to be multiple contamination issues that result from depending in the resin codes. Possibly a bottle is marked as #5 however there is a nylon or EVOH barrier layer which renders the bottle unrecyclable and actually causes severe contamination issues when extruded within a true polypropylene feedstock. There have been other instances where we have found that materials changed but the molds did not, resulting in an altogether wrong marking.
Currently, there is no certification and/or monitoring entity for how the numbers are used. SPI has recognized that their attempt many years ago to simply mark which type of polymer was used in the manufacturing process has now created a problem which even they have spent countless hours discussing at length and yet have the solution. It is definitely a case of having the right intentions and yet utilized for the wrong purpose, beyond their control.
I don't believe there is one specific polymer that is easier to recycle. "Easy" may need to be further defined. How is the material handled and size reduced for recycling? How many facilities take this material? How large and/or diverse are the markets? Is the material a commodity? Where are the facilities and markets located? Those are some of the questions that would need to be addressed in order to determine the ease and efficiency for recycling.
As for your question regarding the smallest biological footprint I don't believe there is one tried and true answer. It depends largely on what the end product is. I would suggest that whatever your material choice is, using PCR is the only sure way to reduce your footprint.
Thank you for your question.
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