Thermax

These self adhesive labels consist of a series of temperature sensitive elements sealed between heat-resistant substrates with transparent windows. Each element changes colour distinctly as its rated temperature is exceeded. The changes are irreversible, providing a temperature history of the surface being monitored.
The labels will not de-laminate when removed for reference and can be attached to an inspection report to serve as a permanent record.
The temperature sensitive elements are phase change indicators which use thesharply defined melting points of a series of specially purified organic chemicals to give the unique, high precision, colour change effects. Each temperature element uses a different chemical compound and is made separately by applying a coating containing the chemical to a special absorptive paper substrate. When the rated temperature is exceeded, the chemical melts and is absorbed by the substrate, causing a permanent colour change. Up to ten elements can be combined together on a single label.

A colour change from silver white/orange to black indicates the highest temperature that has been reached.