The use of polyethylene terephthalate (PET) for packaging has seen tremendous growth that can be attributed to the material’s ability to offer light weighting options, unique container designs, clarity, long shelf life using special additives and/or multilayer structures and recyclability. Unfortunately, only non-colored and lightly-tinted blue PET bottles offer reclaimers a high value in today’s market. This is because colored PET bottles have limitations for their reuse and therefore a much lower value.
Multilayer PET bottles, and those that contain additives that are problematic to recycling (such as oxygen scavengers and ultraviolet light absorbers), can easily slip through and become part of the PET bale. Reclaimers must then try to identify and remove those items.
As a result, many brand owners who want to support sustainability initiatives by producing truly recyclable bottles have shied away from some technical developments that could give them additional right-weighting or longer shelf lives. They realize that these technologies would present problems to the PET reclaimers and, in turn, harm the very type of recycled PET (rPET) they wish to buy for their own reuse.
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Reprocessing of problematic bottles
The reprocessing of these problematic bottles into rPET for other uses is poor since this material offers the reclaimers a much lower economic return. Additionally, colored bottles (other than those dyed light blue and to some extent green) offer reclaimers very low returns. There simply is not enough of any one color to allow for the development of a unique color stream.
For U.S. PET beer applications, approximately 10 million pounds of clear, green and amber bottles are created. This is far below the volume needed for the reclaimers to economically produce even a dedicated amber rPET product line. However, if amber PET pharmaceutical and beer packaging usage increases, the reclaimers will eventually face the need to develop an outlet for this material.
New recycling opportunities
Interestingly, a significant amber PET beer bottle market might allow for a recycling outlet for other non-colored, yet problematic PET bottles. The types of bottles that are known to cause excessive yellowing during the reprocessing melting steps might be added to the amber stream as well. Thus, an opportunity to create a market for problematic PET bottles may be available that does not exist today. Again, rigorous performance testing would need to be done to understand how the incorporation of these types of non-colored PET bottles might impact such an amber recycle stream.
Now is the time to begin addressing this issue. The goal is to how best to handle an amber colored bottle stream in the future so that amber can add value to the reclaimer’s operation rather than detracting from it.
Author: Frank Schloss, Ph. D., Materials Evaluation Group, Plastic Technologies, Inc., has more than 30 years of experience working in the plastics packaging industry in analytical testing, closure development and applied materials research covering a wide range of materials including PE, PP, PVC, TPE, TPO, PLA and PET.
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