TRANSPARENT INFRARED ABSORBING MATERIALS

摘要

An infrared absorbing material, an infrared absorbing ink formulation and a method of production are provided in which at least one infrared absorbing dye is supported on nanoparticles having an average size not greater than 100nm in at least one direction. The dye-supporting nanoparticles may be dispersed in a carrier vehicle such that the infrared absorbing material or ink is substantially transparent to visible radiation. The infrared absorbing material and ink are particularly suitable for use in banknotes and other security documents.