Digital printing technology represents a counterfeiting threat and a counterfeiting deterrence opportunity. Digital reproduction methods have been used to produce holographic and printed features similar to those on banknotes. As digital technology continues to improve, the quality of those features will become nearly indistinguishable from intaglio printing, offset printing and holograms. Optically active devices and inks have been useful to slow counterfeiters, but security document and feature designers need more tools. The toolbox for digital technologies is very large and being exploited by the counterfeiters, but their toolbox has been limited to commercially available digital technologies. Security designers also need to take advantage of this toolbox with the additional lever of secure materials. By leveraging digital technologies with secure materials, variable information and integration with other security features,
security document designers can create new, attractive features that are hard to replicate. The high level of difficulty to create security materials in the sub-micron to nanometer size range with multiple functionalities is one barrier. Creating inks that are formulated to fit the stringent requirements for custom digital printing methods creates another barrier to unauthorized reproduction. All of the other valuable aspects of digital technology are therefore accessible only to those with access to these secure materials. Leveraging these digital materials to make optical effects make them useful for the end-user authentication. Furthermore, use of digital technologies allows the incorporation of variable data that can be authenticated visually or using proprietary algorithms and detection / sorting equipment.
Particles are frequently used to impart security features to high value items. These particles are typically produced by traditional methods, and therefore the security must be derived from the chemical composition of the particles rather than the particle production process. Here, we present new and difficult-to-reproduce particle production processes based on spray pyrolysis that can produce unique particles and features that are dependent on the use of these new-to-the-world processes and process trade secrets. Specifically two examples of functional materials are described, luminescent materials and electrocatalytic materials.