Lifelines Technology, Inc.

Raymond M Arnold

Thaddeus Prusik

Stephen C Fields

Allan P Piechowski

An activatable time-temperature indicator system useful in tracking the thermal exposure history of a temperature-sensitive perishable product and providing a visually-distinct signal, such as a change in color density, at the expiration of a predetermined time-temperature integral comprises a first element, such as a direct thermal printing label ( ), comprising a composition ( ) having at least a first co-reactant of a color-forming reaction. A second, activator element, such as an adhesive tab ( ) capable of being affixed to the label element, comprises an activator component ( ), such as a second co-reactant of the color-forming reaction or a solubilizing agent for prompting the interaction of the co-reactants of the label composition. The activator tab element is affixed to the label composition to activate for reaction at ambient conditions the normally high-temperature color-forming composition ( ) of the label at about the same time as the label is affixed to the perishable product. Such an ability to effect the initiation of the indicator reaction at a given time eliminates any unknown, premature color formation in the indicator system to thereby ensure a true time-temperature history of the perishable product.

Activatable time-temperature indicator system

A time-temperature indicator label for measuring the length of time to which a product has been exposed to a temperature above a pre-determined temperature is provided. The period of time of exposure is integrated with the temperature to which the indicator is exposed. The label is a composite of a plurality of layers adapted to be adhered at its underside to a product container. The label includes a printable surface layer, a longitudinal wicking strip that is adhered underneath the surface layer substantially at the opposite extremities only of the wicking strip and a lower substrate layer forming an envelope with said surface layer. A heat-fusible substance, which melts and flows above a pre-determined temperature, is applied on the surface of the wicking strip contiguous to at least one of the ends of the wicking member. When the heat-fusible substance is exposed to a temperature above the pre-determined temperature, the heat-fusible substance flows along the length of the wicking member. The label has a printable surface layer and is sealed at its peripheral edge to the peripheral edge of the substrate layer. These layers encapsulate the wicking member and the heat-fusible substance. The surface layer is provided with a sight window at an intermediate location over the wicking member through which the progress of flow on the wicking member is observed.

Time-temperature indicator device and method of manufacture

A time-temperature indicator label for measuring the length of time to which a product has been exposed to a temperature above a pre-determined temperature is provided. The period of time of exposure is integrated with the temperature to which the indicator is exposed. The label is a composite of a plurality of layers adapted to be adhered at its underside to a product container. The label includes a printable surface layer, a longitudinal wicking strip that is adhered underneath the surface layer substantially at the opposite extremities only of the wicking strip and a lower substrate layer forming an envelope with said surface layer. A heat-fusible substance, which melts and flows above a pre-determined temperature, is applied on the surface of the wicking strip contiguous to at least one of the ends of the wicking member. When the heat-fusible substance is exposed to a temperature above the pre-determined temperature, the heat fusible substance flows along the length of the wicking member. The label has a printable surface layer and is sealed at its peripheral edge to the peripheral edge of the substrate layer. These layers encapsulate the wicking member and the heat-fusible substance. The surface layer is provided with a sight window at an intermediate location over the wicking member through which the progress of flow on the wicking member is observed.

An accurate monitoring of the conditions of a perishable product is achieved by integrating two indicator types - a primary indicator which develops a color change as a result of cumulative time-temperature exposure and a threshold second indicator - into a single device. The combination of the two indicators in the same indicator device provides a human readible signal that gradually and irreversibly develops color as a function of time and temperature and more closely monitors the actual condition of a deteriorative product than does a single indicator. Important features of this integrated monitoring device are reliability and printability. The primary indicator in the system is assisted in color development by the secondary indictor that is set to trigger at a predetermined temperature. When this temperature is reached or exceeded both indicator mechanisms function in an additive mode to cause a break in the typical Arrhenius curve, which a primary indicator alone produces. This can be used to signal actual rather than an apparent the end of a product life. The secondary indicia can be formulated to change very rapidly as would be needed to detect the thawing of a frozen product or modified so as to act more slowly, i.e. over at time-temperature range, and may comprise a substance that melts or changes some physical property at a given temperature.

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Harrisonville, NJ, United States of America

Raymond M Arnold