Self-adhesive materials specialist HERMA is causing a minor sensation with its removable and entirely plasticizer-free adhesive 42Lpp after its endorsement for direct food contact by the German test institute ISEGA.
Approval has been granted not only for dry and moist foodstuffs, but also for fatty foods (correction factor 3).
Dr. Thomas Baumgärtner, managing director of HERMA says: "An adhesive that can be removed without leaving any residue on a wide variety of surfaces while offering such extensive food compatibility has thus far proven elusive in practice, thanks to our multi-layer technology, we can offer both benefits at once with an acrylate-based dispersion adhesive."
As a consequence, the compromises that arise with rubber-based adhesives during conversion are no longer an issue.
"Because of the special second layer, moreover, we can entirely forgo the plasticizers, which often attack the substrate and migrate through the label stock."
Labels to which this adhesive is applied therefore retain their visual and physical properties. In addition, the adhesive can be applied to thermal paper grades as label materials. With immediate effect, furthermore, the removable adhesive 42Lpp can also be supplied as standard with label stock made of film. The available options are a white PP film (grade 880), a transparent PP film (grade 885) and a white PE film (grade 851).
The 42Lpp adhesive can be peeled off many surfaces absolutely cleanly, without leaving either any residue or an outline. This property is retained even after prolonged exposure to light and heat. Also banished is the problem of "ghosting" – the non-tacky, but milky and distinctive adhesive film that can be left behind on some surfaces. The 42Lpp adhesive therefore offers especially good compatibility with glass surfaces. Outstanding results are likewise obtained when it is peeled off plastic surfaces, such as PP and rigid PVC; coated, zinc-plated and powder-coated metals; and uncoated papers.
The ideal adhesive and peeling attributes originate from the multi-layer technology and HERMA's guarantee of extremely consistent coating, which applies to both this and the likewise peelable 42N adhesives. HERMA has halved the customary tolerances for adhesive coatings to just ± 1.5 grams per square metre – without modifying the effective amount of adhesive applied.
Especially with peelable adhesives, it is essential to avoid "peaks" and "valleys" when the material is being applied in order to rule out both residues and insufficient tack. The key to achieving these low tolerances lies in the use of curtain coating technology – a field in which HERMA ranks among the pioneers worldwide.