Fuente: WIPO "circular economy" A laminate film, package formed from the laminate film, and method for constructing the laminate film are provided. The laminate film includes a barrier layer, sealing layer, adhesive layer, and thermochromic ink layer. The thermochromic ink layer includes thermochromic ink such that the thermochromic ink is trapped between the barrier layer and sealing layer. The thermochromic ink has a first visual appearance and is adapted to permanently change to a second visual appearance upon exposure to certain pre-determined conditions during a sealing process and to maintain permanence of the second visual appearance during post-sealing processes. The package includes the laminate film, a substrate, and a packaged article. The edges of the laminate film are sealed to the substrate and form a seal. The seal forms a perimeter about the article and has the second visual appearance, including a different color, such that the integrity of the seal is quickly and confidently verifiable by an observer.