Sustainable Flexible Packaging: Materials to Be Used and Avoided
Sustainability has become a goal to be strived for in many industries, and the packaging industry is no exception. As regards flexible packaging, manufacturers have multiple options to earn sustainability points – start-up waste reduction, downgauging, e-beam offset printing without solvents and photoinitiators, to mention just a few. Material choice is an essential piece of this jigsaw. The question, therefore, is: What materials should be used in sustainable flexible packaging and what, on the other hand, should be avoided?
Recyclability as the prerequisite for sustainability
Material selection plays a key role in determining the recyclability (and sustainability) of the packaging, as recycled materials, the so-called recyclates, can be used again in packaging production.
At the end of its life cycle, the packaging should be sorted into the recycling stream on the basis of the dominant material used in the structure. Mono-material packaging is currently preferable, and the reason is obvious – it is easier to recycle.
On the other hand, multi-material packaging has a different material of the inner layer to the outer layer, which includes a risk of being sorted into an incompatible fraction. That can lead to disruption of the recycling process. An example is PET in the PE, PP or mixed polyolefin structure.
The aim is mono-material structures containing one material type, such as PE (LDPE, LLDPE, HDPE), PP or PET. They are gaining importance as the quantities of flexible packaging collected to be recycled increase and more end-market applications are developed.
Our subsidiary Chemosvit Folie is constantly developing mono-material packaging solutions. An example is a multipurpose bag with a clean PE structure that contains PCR (post-consumer) and PIR (post-industrial) mechanical recyclate. The solution also won the WorldStar 2022 Award.
Polyolefin-based structures are the combination of PE (polyethylene) and PP (polypropylene). Such structures are partially accepted for recycling.
There is currently no recycling infrastructure for PVC (polyvinyl chloride) packaging in Europe. The prominent disposal options for this material are therefore waste incineration or landfilling. When used within the packaging, it also contaminates other plastic types which could otherwise be recycled. For that reason, PVC should be avoided from flexible packaging structures.
PET is incompatible with a PE, PP or mixed polyolefin mechanical recycling process. Therefore, it should be on the outer surface of the PE, PP or mixed PO laminate so it can be identified and removed from the mechanical recycling process.
Paper is generally recyclable with the paper fraction and other paper formats. It should be the dominant material by weight in the structure to be able to be identified as paper in the sorting process.
An example of a paper-based solution is the packaging for puffed rice covered in caramel by our subsidiary Chemosvit Folie. The solution received the Packaging of the Year award, as it is not only fully recyclable, but also biodegradable and water-soluble.
Structures containing aluminium
Flexible packaging containing aluminium foil can be found in dairy, dry food, pharmaceutical, pet food and other segments thanks to its high-preservation properties. The main problem, however, is that structures containing aluminium are hardly recycled in the current waste management infrastructure.
Coffee is a product requiring excellent barrier properties to preserve its quality and aroma. Our colleagues at Chemosvit Folie replaced the non-recyclable PET/Aluminium/PE laminate with a fully recyclable PP-based structure.
Generally, flexible packaging manufacturers should focus on mono-material structures and avoid those containing PVC and aluminium as those materials are hardly recyclable in the current recycling infrastructure.