There are a couple of important reasons why digital printed alu cans are more sustainable than sleeved or labelled ones:
- The higher economic value of recycled aluminum (no contamination)
- Better recoverability of the aluminium (e.g. sleeved cans mistaken for a plastic container and sorted out during the recycling process)
- Less downtime of recycling machinery due to plastics
- No hazardous emissions during the de-lacquering thermal treatment when plastics or adhesive are burnt
The Aluminium Association has published a design guide for aluminum containers that highlights these points and recommends how to enable the best recyclability e.g. by using "...emerging small scale digital printing technology" that "has advanced to the point of being price competitive with shrink-wrapped cans while maintaining the recyclability of the aluminium.”
Furthermore, they also confirm the points above: "The use of plastic labels, shrink sleeves, and lids may impact the apparent conductivity of aluminum containers and, therefore, reduce the collection rate during eddy current separation. Aluminium cans with PET sleeves could also be incorrectly identified as PET by optical scanners and be lost as PET prior to eddy current separation. As contaminants in the aluminium recycling stream increase, the economic value of recycling decreases, reducing incentives for aluminum container recycling."