Manufacturers of packaging made from multilayer laminates have had to dispose of their production-related scrap up to now. This is because printed PET-PE films are not considered recyclable. The good news is that with the right blown film technology, producers can make the impossible possible and use the offcuts from their printed laminates as a valuable raw material.
Countless items in both the food and non-food sectors are now packaged in stand-up pouches - soap, nuts or smoothies, for example. The classic material combination for such packaging is PET/PE. The two films are produced individually and then bonded together. While the PET in these multilayer laminates provides good rigidity and appearance, the PE serves as a sealing film - a combination that ensures excellent functionality but is problematic for recycling: While manufacturers today usually recycle the production-related scrap from their monomaterial films directly back into the extrusion process, this is not possible with PET/PE composites. As a result, large quantities of material are lost to the industry. The hurdles for recycling this post-industrial waste are primarily the following:
Recycling hurdle 1: PET and PE are chemically incompatible
PET and PE behave chemically in much the same way as water and oil. When melting the material again to produce a homogeneous mixture, which is absolutely necessary for the extrusion of a film, is not easily possible.
Recycling hurdle 2: Packaging is printed
Rejects that are produced during further processing into finished packaging are usually printed with printing inks that consist of a wide variety of components, such as color pigments, additives and various binders. Some of these elements gas out during melting in the extruder. This is a problem for stable extrusion - bubbles and holes form in the film. For printed film, regardless of the raw material, the following therefore applies in principle: in the single-screw extruder, a maximum of 20 percent of this material can be added as recycled content.
