Many challenges exist throughout the mechanical recycling value chain illustrated above, starting with the availability and execution of a collection infrastructure. For example, only about 15% of plastic waste is collected in the US, but in Japan and Germany, the number is 87% and 67% respectively due to smaller geographic distances and extensive investment in waste collection infrastructure.
Once material has been collected, it is necessary to sort the plastic. In some places around the world, this sorting is done by hand, while in other locations advanced sorting robots and sensors are used to separate plastic types from each other and from other materials in the recycling stream. Sorting is important step in the process, as many plastic types can not be mixed or the resulting recycled material will not be suitable for reuse.
Cleaning the sorted plastics presents the next challenge: is it possible to remove all pollution, labels, and residues? The answer is YES, but it’s certainly not easy. Complex packaging design means that multiple layers might need to be separated, inks and adhesives must be removed, and any other contaminants must be washed away.
Finally, the sorted, cleaned plastic must be reprocessed. Heating plastics to melt and reform them also leads to degradation of the polymer itself. Not knowing exactly where the plastics come from means that there are also variations in the quality and age of the material. These variations can lead to poor processing of the material and result in low quality, low performance PCR. Additional chemical stabilizers can help reduce these issues but require testing to optimize the best solution.
Successfully recycling plastics into high quality applications at large scale requires collaboration at each point of the value chain.
