| abstract |
Device for indicating the previous history of a product, comprising the following layers: (a) a coating layer impermeable to moisture (1), (b) an indicator layer (2), comprising at least one indicator, (c) an activator layer (3), comprising at least one activator, as well as (d) an optional delay layer (4), wherein the coating layer is located on the indicator layer, the activator layer and retarding layer, where the indicator layer is located between the coating layer and an optional retarder layer, and where the activator layer may be absent if an indicator that is activated by H2O is used , characterized in that at least one of the layers comprises a cellulose derivative selected from hydroxypropyl methylcellulose (HPMC), methylcellulose (MC), hydroxypropyl cellulose (HPC), carboxymethyl cellulose (CMC) and mixtures thereof, preferably HPMC. |