Improve Invisible Ink Production by the Europium Complexes

Document Type: Research Paper


1 Faculty of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran

2 Department of Chemistry, Amin University of Police Sciences, Tehran, Iran


The invisible inks have many applications, including the use of banknote printing, code load, security
documents and much of its application in the exchange of security information. Photoluminescence
properties of lanthanide compounds that attracted the attention of many scholars in recent decades are one of
the important factors in drying and fluidity of the ink. The solvent evaporation rate has a special importance
in the formulation of resin systems. The solvent evaporation rate is often expressed in compare with a
standard solvent evaporation rate, such as normal butylated acetate or ethyl ether. The mixing of some
solvents may be used due to the formation of an azeotrope and the more rate of evaporation. In the
formulation of the inks, the use of the weight ratio compared with the volume relationship has this
advantage, which requires less mathematical calculations and operations, especially that this score is useful
during the early stages of formulation. In this research, from 160 materials that were used, 11 items played a
fundamental role, which were selected based on their formulation planned. The purpose of this research was
to produce invisible ink.For this purpose, the relevant complexes were prepared, designed and the
composition of the percentage of invisible ink was optimized. Eventually, obtainedresults were evaluated.