Thermochromic ink

Thermochromic ink (also called thermochromatic ink) is a type of dye that changes color when temperatures increase or decrease.[1][2][3] Often used in the manufacture of many toys or product packaging, as well as thermometers. Thermochromic ink can also turn transparent when heat is applied; an example of this type of thermochromic ink is found on corners of an examination mark sheet. This proves that the sheet has not been edited or photocopied, and also on certain pizza boxes to show the temperature of the product.

Use on packaging can be to detect temperature history during shipping and to indicate proper heating in an oven.

Examples

On June 20, 2017,[4] the United States Postal Service released the first application of thermochromic ink to postage stamps in its Total Eclipse of the Sun Forever stamp[5] to commemorate the solar eclipse of August 21, 2017. When pressed with a finger, body heat turns the black circle in the center of the stamp into an image of the full moon. The stamp image is a photo of a total solar eclipse seen in Jalu, Libya, on March 29, 2006. The photo was taken by retired NASA astrophysicist Fred Espenak, aka "Mr. Eclipse".

See also

References
  1. Thamrin, T S (2022). "Thermochromic ink as a smart indicator on cold product packaging - review". IOP Conf. Series: Earth and Environmental Science. 1063 (1): 012021. Bibcode:2022E&ES.1063a2021T. doi:10.1088/1755-1315/1063/1/012021. S2CID 251368125.
  2. Yan, Xiaoxingng (2020). "Effect of Concentration of Thermochromic Ink on Performance of Waterborne Finish Films for the Surface of Cunninghamia Lanceolata". Polymers. 12 (552): 552. doi:10.3390/polym12030552. PMC 7182879. PMID 32138270.
  3. Kulˇcar, Rahela (2011). "Dynamic colorimetric properties of mixed thermochromic printing inks". Color Technology. 127 (6): 411–417. doi:10.1111/j.1478-4408.2011.00338.x. Retrieved 24 December 2022.
  4. "Total Eclipse of the Sun to be commemorated on a Forever Stamp". United States Postal Service. 2017-04-27. Retrieved 2017-07-10.
  5. "Total Eclipse of the Sun". United States Postal Service (store). Archived from the original on 2017-09-24. Retrieved 2017-06-27.
This article is issued from Wikipedia. The text is licensed under Creative Commons - Attribution - Sharealike. Additional terms may apply for the media files.