Smart anticounterfeiting approach: Mineral oil-free offset ink with fluorescent features and audio signal, detected using a customized combi-reader

Abstract

Counterfeiting of documents or branded products is considered as a menace due to their negative impact on economy and society. Therefore, there is an immediate need to develop anti-counterfeiting solutions to identify or distinguish illicitly reproduced fake items among the genuine ones. Though several anti-counterfeiting technologies are available, security inks have garnered immense importance due to the diverse options of incorporating unique safety features in them. The present study demonstrates the formulation of a new, sustainable and stable mineral oil-free, invisible offset ink incorporating two types of fluorophores (DC-Red and UC-Green), which when printed on diverse substrates reveals distinctive identification features detectable through a specially designed single unit device. The prints obtained using the ink on various types of paper and fabric substrates reveal good photostability and adherence features. The printed samples display prominent red down-conversion fluorescence under 365 nm UV source and green up-conversion fluorescence upon shining with 980 nm laser beam in combination with a beeping audio response upon irradiating with 940–980 nm near-IR source using an IR taggant reader. These multi-level covert security features achieved using a single sustainable formulation are difficult to identify/replicate by the forger but can be easily validated by the user by means of the newly designed combi-reader. The smart programmable single unit combi-reader comprising of a buzzer together with UV and IR light sources is fabricated to authenticate the security features, rather than three independent devices with different light sources and detectors. Visually observable down-conversion and up-conversion fluorescence coupled with audible beeping that are detected using the new customizable combi-reader enables easy, rapid, and non-destructive identification as well as authentication of genuine products or documents.