Patent ID: 8722575

Claim:
A packaging material comprising a colored element, which at a predetermined temperature below which the pharmaceutical product must be kept, discolors partially, revealing a marking, wherein: (a) the colored element comprises a first portion, which forms the marking printed with a conventional ink, and a second portion printed with a thermochromic ink; (b) the thermochromic ink is colored below the predetermined temperature and becomes colorless when the predetermined temperature is reached or exceeded; (c) the first portion and second portion are arranged so that the first portion is substantially invisible below the predetermined temperature, but becomes visible when the predetermined temperature is reached or exceeded, (d) the first portion and second portion of the colored element are situated alongside each other, and (e) the packaging material is suitable for a pharmaceutical product, wherein the color of the thermochromic ink is, below the predetermined temperature, as similar as possible to that of the conventional ink, and when the first portion has spaces without the conventional ink, the second portion of the colored element also covers the spaces without the conventional ink.