US 12,392,672 B2
Printable irreversible minimum temperature indicator
Mohannad Abdo, Clifton, NJ (US); and Thaddeus Prusik, Stroudsburg, PA (US)
Assigned to ZEBRA TECHNOLOGIES CORPORATION, Lincolnshire, IL (US)
Appl. No. 17/292,323
Filed by Temptime Corporation, Morris Plains, NJ (US)
PCT Filed Nov. 6, 2019, PCT No. PCT/US2019/059988
§ 371(c)(1), (2) Date May 7, 2021,
PCT Pub. No. WO2020/097154, PCT Pub. Date May 14, 2020.
Claims priority of provisional application 62/756,794, filed on Nov. 7, 2018.
Prior Publication US 2021/0396601 A1, Dec. 23, 2021
Int. Cl. G01K 11/18 (2006.01); C09D 11/50 (2014.01)
CPC G01K 11/18 (2013.01) [C09D 11/50 (2013.01)] 24 Claims
OG exemplary drawing
 
1. A multi-event historical low temperature excursion exposure indicator comprising:
a printable substrate; and
a pattern on the substrate configured to provide a visual indication of prior exposure to progressively colder temperatures, the pattern including at least two thermochromic compositions each printed on a respective discrete area of the substrate, the at least two thermochromic compositions further comprising:
a first thermochromic composition printed on a first discrete area of the substrate and having an initial color state, the first thermochromic composition changing from the initial color state when descending to a temperature below a first low temperature threshold to an exposed color state providing a first visual indication of prior exposure below the first low temperature threshold, the first thermochromic composition maintaining the first visual indication until the first thermochromic composition is exposed to a temperature higher than a first high temperature threshold, the first thermochromic composition reverting to the initial color state when exposed to the temperature higher than the first high temperature threshold; and
a second thermochromic composition printed on a second discrete area of the substrate and having a second initial color state, the second thermochromic composition changing from the second initial color state when descending to a temperature below a second low temperature threshold to a second exposed color state providing a second visual indication of prior exposure below the second low temperature threshold, the second thermochromic composition maintaining the second visual indication until the second thermochromic composition is exposed to a temperature higher than a second high temperature threshold, the second thermochromic composition reverting to the second initial color state when exposed to the temperature higher than the second high temperature threshold,
wherein the second low temperature threshold is lower than the first low temperature threshold,
wherein the first and second low temperature thresholds are in the range of 15° C. to −20° C., and
wherein the first high temperature threshold is at least 35° C. higher than the first low temperature threshold, and the second high temperature threshold is at least 35° C. higher than the second low temperature threshold.