Improved time-temperature indicator device and method of manufacture

摘要

A time-temperature indicator label for signalling the exposure of a product to a temperature above a selected pre-determined temperature and after a time period that exceeds said temperature. The label is composed of a substrate layer adapted to be adhered at its underside to a container a wicking strip member that is adhered at its underside, substantially only at the opposite extremities of the member only to the surface of said substrate. A heat-fusible substance, which melts and flows above a predetermined temperature, is applied on the surface of the wicking strip and contiguous with at least one of the ends of said wicking member. When the heat-fusible substance is exposed to a temperature above said pre-determined temperature it flows along the length of said wicking member. The label has a printable surface layer superimposed over said wicking member and meltable material and is sealed at its peripheral edge to the peripheral edge of the substrate layer encapsulating said wicking member and meltable material. The surface layer provided with sight window at an intermediate location over said wicking member and through which the progress of flow on the wicking member is observed. <IMAGE>