Colorimetric description of thermochromic printing inks

  • Maja¸¸ Jakovljević University of Zagreb, Faculty of Graphic Arts, Getaldićeva 2, Zagreb, Croatia
  • Rahela Kulčar University of Zagreb, Faculty of Graphic Arts, Getaldićeva 2, Zagreb, Croatia
  • Dario Tomašegović University of Zagreb, Faculty of Graphic Arts, Getaldićeva 2, Zagreb, Croatia
  • Mojca Friškovec Cetis, Graphic and Documentation Services, d.d., Čopova 24, Celje, Slovenia
  • Marta Klanjšek Gunde National Institute of Chemistry, Ljubljana, Hajdrihova 19, Slovenia

Abstract

The dynamic colour of three commercial reversible thermochromic inks were studied. Thermochromic printing inks change their colour according to a change in temperature. The two types of thermochromic inks are based on leuco dyes and liquid crystals. The thermochromic effect achieved by liquid crystals is quite different from the effect achieved with leuco dyes. Leuco dyes change from a coloured to a colourless state, or from one colour shade to another due to structural changes inside leuco dye molecules under assistance of developer. Liquid crystal inks change colour continuously throughout the spectrum, producing iridescent colours starting from red and shifting to blue part of the spectrum with temperature. The colour change results from the way light interacts with special arrangement of liquid crystal molecules to produce coloured reflection by interference, and with the variation of this structure with temperature. In this paper we will present differences between two types of thermochromic printing inks giving careful colorimetric characterization.

Published
Jul 23, 2017
How to Cite
JAKOVLJEVIĆ, Maja¸¸ et al. Colorimetric description of thermochromic printing inks. Acta Graphica, [S.l.], v. 28, n. 1, p. 7-14, july 2017. ISSN 1848-3828. Available at: <http://actagraphica.hr/index.php/actagraphica/article/view/119>. Date accessed: 17 aug. 2017.
Section
Original Scientific Papers