How do VOID labels prevent tampering?

VOID labels prevent tampering by using a special adhesive and film construction that leaves a permanent VOID message on both the label and the surface underneath if someone tries to peel and reapply the label, making any removal attempt permanently and visibly evident.

The mechanism relies on a split-layer adhesive: the label’s adhesive is engineered to bond more strongly to the substrate than the printed film bonds to its own adhesive layer. When someone attempts to peel the label off, the top printed layer separates unevenly from the adhesive layer, revealing a pre-printed VOID pattern in the areas where the film has lifted, while a mirror-image residue of the VOID text often remains stuck to the substrate itself. This means the tampering evidence exists in two places at once and cannot be concealed by simply reapplying the same label or a replacement.

Because the effect depends on the adhesive-to-substrate bond being stronger than the film-to-adhesive bond, VOID labels need to be matched to the specific surface they will be applied to; a mismatch can result in the pattern not revealing cleanly or, conversely, damaging the underlying surface. VOID labels are commonly used on product seals, cartons, warranty stickers, and closures where any unauthorised opening needs to be immediately obvious to whoever inspects the product next.