| abstract |
A tamper indicating device includes a light transmissive backing and a layer of adhesive. The backing comprises a blown film including a first, continuous phase and a second, discontinuous phase. The backing is normally light transmissive, and becomes opaque upon tampering sufficient to internally delaminate said backing. Preferably, the blown film contains from 60 to 85 parts by weight of the first, continuous phase and from 15 to 40 parts by weight of the second, discontinuous phase. More preferably, the first phase comprises polypropylene and the second phase comprises an ethylene/vinyl acetate copolymer or ethylene/vinyl alcohol copolymer or an ethylene/vinyl acetate/vinyl alcohol terpolymer. The tamper indicating device can include either or both of an initially viewable indicia that becomes obscured upon internal delamination of the backing and a latent indicia that becomes viewable upon internal delamination of the backing. |