Packaging material with a coloured element which at a predetermined temperature discolours partially, revealing a marking, and method for producing this material
It is disclosed a packaging material (1) for a pharmaceutical product. The packaging material comprises a colored element (2) which at a predetermined temperature, below which the pharmaceutical product must be kept, discolors partially, revealing a marking. The element is formed by a first portion forming the marking (2′) printed with conventional ink, and a second portion (2″) printed with thermochromic ink. The thermochromic ink is colored below the predetermined temperature and becomes colorless when this predetermined temperature is reached or exceeded. The two portions are arranged so that the first portion is invisible below the predetermined temperature, but becomes visible when this temperature is reached or exceeded.
