Concrete ways to minimize contamination of the PET recycling stream

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Recycling has become an inseparable element of the circular economy. Brand owners are committed to ambitious recycled content goals as well as the desire for their packaging to be post-consumer recyclable. There is no denying that recycling reduces the carbon footprint and eliminates the need for landfill.

When it comes to PET, there are significant challenges in obtaining a good, clean material to achieve these goals. Here are some of the challenges:

  • Recycling rates in the United States remain low, which is significantly lower than efforts in Europe. Less recycling means fewer materials are available to produce next-generation materials.
  • Consumers do not always follow local recycling rules.

Brands are striving to make their packaging recyclable, but efforts must increase and further technological advances must be made. These challenges can compromise the quality of the recycled resin at a time when waste pickers are looking for more material.

Another part of this equation is how the bottles are collected, whether at the curb or in the locker. The latter requires that a bottle be sold with a refundable deposit. Lockers are refundable upon return of the bottle to participating retailers. The deposit approach is used in several states and has two advantages for recycling:

  • Recycling usage is significantly higher compared to no deposit states.
  • The quality of recycled PET from depot states is superior to curbside or municipal recycling programs because contamination levels are lower as PET bottles are not mixed with other packaging materials .

In deposit-free states, single-stream recycling has won favor with FRMs and consumers. Because it is easy to do, this approach has been shown to increase the likelihood of consumers participating in recycling programs. The downside is the contamination that comes with the combination of all the packaging materials. Here are some of the challenges with this approach:

  • Non-PET packaging materials such as corrugated cardboard, HDPE, glass, PP and PVC;
  • Labels, inks and residues of glue and adhesives;
  • Metals: ferrous (magnetic) and non-ferrous (aluminum);
  • Product residues, dirt and various debris;
  • Coatings (both chemical and plasma deposited);
  • Non-adherent barrier layers such as ethylene vinyl alcohol (EVOH) and nylon;
  • Dirt, syrup, wood particles from pallets.

Communities can help improve outcomes by providing consumers with information on how to properly recycle in their community. Brand owners and packaging suppliers can help by selecting recyclable materials for their packaging and recycling user-friendly components such as:

  • Label adhesives that separate from PET bottles so that the adhesive can be removed from the waste stream.
  • PET labels with inks that separate and can be removed during recycling.
  • Labels made from other polymers that can be separated from PET and float during recycling.
  • Label inks that do not separate and redeposit on PET flakes.

Cleaning technology is also important. The collector must separate and remove the contaminant to allow a brighter and cleaner appearance of the new generation PET bottles. In turn, this allows for the use of higher levels of recycled content.

Dan Durham is the Director of Technical Customer Services at PTI. He has decades of experience in the field of plastic packaging, ranging from design to injection and blow molding. Durham is currently dedicated to helping multinational brand owners successfully navigate packaging projects, from concept to commercialization, and supporting their sustainability goals.

PTI is a global source for preform and packaging design, packaging development, rapid prototyping, pre-production prototyping, and material evaluation engineering for the plastic packaging industry.


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