Recycling multi-layer packaging has always been a tremendous challenge because it can include as many as 11 individual, ultra-thin layers. These layers typically include PE/PA, PP/PET films together with aluminum, paper and printed layers, with each layer having a specific function in forming a lightweight package structure that provides barrier properties, strength and storage stability. For food packaging, these properties deliver superb protection and freshness for what’s inside (things like fresh coffee, potato chips/crisps and other snack foods, baby food, pet food).
For recycling, it has typically been difficult to separate the layers. When the layers are different materials, they can contaminate recycling streams even if they are able to be separated. That is why today, most multi-layer packaging structures are sent to landfills or incinerated. In some cases, the layers are “downcycled,” being mushed together to produce green-gray pellets that can be used for low-quality, low-volume goods. This keeps packaging out of landfills, but the downside is that valuable resources are wasted in low-volume products.
Industry stakeholders have been working on multiple approaches to redesign multi-layer packaging to make recycling easier without impacting the packaging integrity and its protective performance characteristics. These approaches include:
- Mono-component products—the layered structure is made from materials that are all the same chemically and then each layer is treated with a thin, wet coating to improve performance.
- Chemical recycling—this approach involves breaking the polymers down to their basic building blocks. It’s currently in very early stages and it’s expensive, making it a potential longer-term solution.
- Mechanical recycling—this method focuses on cleanly separating layers at the end of life so they can be captured more cleanly in the right places to avoid recycling contamination.
Independent Testing Yields Promising Results
At Lubrizol, we’ve developed coating solutions that support both layer separation (mechanical) and mono-component approaches. With mechanical recycling, we are focused on making it simpler to separate layers. This approach involves applying a coating between layers so they can be cleanly separated and captured in the appropriate places. With clean separation, the multi-layer packaging can be classified as recyclable (no packaging taxes and adherence to plastics pacts), with valuable materials recaptured and put back into the system. After mechanical recycling, we take the small remaining fragments and move them into a chemical treatment to complete the process.
We took this approach from the beginning because we thought it had the best chance for success, which has been confirmed with recent results from an independent testing center. This testing confirms that this mechanical separation solution for multi-layered packaging allows perfect recyclability of various plastic films, while also maintaining clarity and mechanical properties. It requires no changes in the standard recycling process.
The polypropylene that was used has been recovered and recycled. We were able to make a clear, transparent polypropylene that can be used again. We will be doing additional testing on the recycled polypropylene to determine if it will meet EU compliance for use in food packaging.
A Big Step Forward
This is a tremendous step forward for recyclability in flexible packaging. These results are significant in that this approach opens the door to brighter prospects for the packaging industry, which is facing challenges in moving toward more sustainable products without compromising performance characteristics.
That’s good news for a packaging solution that is billed as environmentally friendlier because it is significantly lighter and thinner than many other packaging options. Moving from glass jars to flexible pouches is a perfect example. The pouches use far less material, less gas to transport and less energy to make them. It’s especially important as regulations and taxes related to packaging continue to expand, as well as voluntary plastic pacts where stakeholders in plastic packaging pledge to commit to being more circular in use. The bottom line: packaging needs to be made more sustainable by being recyclable, reusable or compostable.
Lubrizol has developed coating solutions that support layer separation and mono-material approaches. By exploring a variety approaches, the future looks much better for improving the recyclability of multi-layer packaging.