UV and thermal guard and a process of making and using thereof

摘要

A process of making an image element having an imperceptible message that becomes readily apparent when the image element is exposed to an excessive amount of heat and/or UV radiation is provided. The process comprises providing a first thermally sensitive coating on at least a first portion of the image element; pre-printing a first mark on the first portion of the image element, wherein the first pre-printed mark comprises non-thermally sensitive ink. The image element may be associated with a material such that, upon becoming readily apparent, the imperceptible message provides a warning that the material has been exposed to excessive heat and/or UV radiation.