| abstract |
Security film comprising a monolayer of transparent microspheres supported in a thin layer of binder material, a pressure-sensitive adhesive layer coated on the layer of binder material, and disposed between the pressure-sensitive adhesive and binder layers, at least one patterned layer that has differential adhesion to the pressure-sensitive adhesive layer and the binder layer such that upon attempted elevated-temperature removal of the film from a substrate the film splits, with part of the film remaining on the substrate and part being removed. |