Reversible thermochromic inks for printing
Reversible thermochromic inks react with a colour change to a change in temperature.
The colour disappears after reaching a limit temperature, together with temperature increase, and vice versa – it reappears after the limit temperature is reached, with decrease in temperature. The process of change begins at a specific tempreature, then the transformation of colour (discolouration together with the increase and recolourisation with the decrease) lasts in a range of several degrees. The colour change is reversible – after reaching the initial temperature the ink returns to its original colour.
Reversible thermochromic inks can be used for security (e.g. heating the printout by hand in order to check its authenticity), marketing effects (e.g. covering an underprint containing information by using a thermochromic ink) or as a temperature indicator (e.g. on a product label as the indicator of heating up of cooling off).
A leaflet with a thermochromic print (a heart and a number 3), video 1
A leaflet with a thermochromic print (a heart and a number 3), video 2