Innovative temperature sensitive front labels for bottled of half-litre “Ožujsko pivo”, also called “Žuja”, of “Zagrebačka pivovara” (“Zagreb’s Brewery”) has been printed in Tiskara Reprint in offset-flexo technology on metallized paper of 71 g/m². Every enjoyer of that beer will know if it is drunk at the right temperature.
Part of the design of new label has been printed by thermo-ink which is invisible at room temperature. But, once the bottle of beer chilled to 8 to 9°C or lower, that surface becomes light blue. The effect disappears when the bottle is again warmed up. The standard colours are printed in offset technique, and the thermo-sensitive colour by flexo varnish unit.
The ink sensitive to specific heat of 8°C has been developed for Reprint, and in cooperation with Reprint, by „CTI Inks“ company from Colorado Springs, USA.
Even though print sensitive to heat is not new, Reprint’s label is specific by the way the effect of colour change got achieved using innovative technology of print in offset machine using flexo unit, while previous known colour change effects were achieved by varnish in UV technology or by copperplates. The novelty is also in printing to thermo-sensitive colour to metallized paper.
There were new additional control check-points introduced in the print process, and new measurement devices („cooling plate“), because temperature-sensitive colour is invisible in print. Even the control of positions (so called „pasers“) was demanding accordingly. Sheet of B1 size had to be cooled down to 8°C.