March 30, 2021
The most prevalent recycling method for packaging around the world is mechanical recycling, which refers to operations that aim to recover waste via physical processes such as grinding, washing, separating, drying, re-granulating and compounding.
When plastics are recycled mechanically, polymers stay intact, which permits for multiple re-use of polymers in the same or similar products.
Ideally, a plastic mechanical recycling stream would contain 100% of a single resin type, however, in many packaging applications, performance needs require us to use multiple types of plastics held together in layers.
Multi-materials or their components can compromise the quality of or “contaminate” a recycling stream. That’s why it’s important for plastic packaging producers like Sealed Air not only to ensure our products will not adversely impact the process, but that we label or make claims for our products that are accurate, straightforward, and transparent.
Because the best way to determine mechanical recycling stream compatibility is to physically test mixed plastic products in a setting that accurately reflects the processes to be used in real life, Sealed Air has now established a polymer processing laboratory with the necessary equipment and methods available that will allow us to conduct mechanical recyclability testing.
While we use various procedures, we follow international protocols published by both Plastic Recyclers Europe (PRE) and the Association of Plastics Recyclers (APR) for benchmark and critical guidance testing of flexible plastic packaging.
These protocols help us assess the ability of our packaging materials to be mechanically recycled into pure materials, such as polyethylene or polypropylene. The test procedures are stringent and well defined, starting with grinding of the test material, blending with control resin to manufacture new plastic pellets and blowing these into a new film product.
Adhering to such strict protocols allows us to be confident that a given material will be compatible (or not) with a mechanical recycling stream, and we, in turn, can pass that confidence on to our customers.
When plastic packaging material is a simple monomaterial, we can use a less rigorous certification known as a desktop certification, where the evaluation criteria is based on the chemical composition of the sample and the allowable percentage of possible contaminants.
Desktop certification is faster and more economical than lab testing, but in our opinion, for complex structures, it doesn’t and can’t give you the most accurate result. That may not sound like a big deal – here’s why it is: improperly labeled materials that enter and possibly contaminate a recycling stream could devalue the quality of recycled materials to the extent that the recycling process itself could become unprofitable.
When the recycling process loses money, facilities are forced to restrict resources or even shut down, which further reduces the availability of and access to plastic recycling. If you’re a FMCG, CPG, or food company that uses our packaging, you already know the importance of plastic – what you may not know is that we all have a role to play to ensure the integrity of our recycling streams – and that starts by making verifiable claims.
Shown above: extruders in the Sealed Air test lab. Blown film is considered by the APR as the "most stringent application and the preferred way to test innovations for recyclability."