Counterfeit products are not only the source of significant economic loss but can endanger health and life. Often, important active substances are lacking in counterfeit medicines which look deceptively like the original. This can have drastic consequences. Thus responsible manufacturers provide their medicines with a safety seal. This seal offers characteristics such as optical tilting, which changes the color of the label, high color brilliance and particularly good machine-readability, characteristics which constitute serious deterrents to the “product pirates.”

Scientists at the Fraunhofer Institute for Interfacial Engineering and Biotechnology IGB in Stuttgart (Germany), together with its industrial partner identif GmbH (Erlangen, Germany), have developed a new approach for the anti-forgery security of packaging. “We coat plastic films with fluorocarbon nano-layers, on top of which the metal layer generating the color effect is applied,” explains Dr. Michael Haupt, project manager at the Fraunhofer IGB. “The advantage is that the basic characteristics of the material remain unaltered, while the surface of the film is optimized by the nano-coating for further processing.”

Dr. Christian Oehr, head of department at the Fraunhofer IGB, expounds: “The nano-layers are applied in a low-pressure plasma process. This is carried out by placing the label into the vacuum chamber of a plasma reactor. We then introduce fluorine gases at low pressure and ignite them by applying a voltage. We can deposit different coat-ings with defined properties on the label surface, depending on the proportions of electrons, ions, neutrons and photons in this luminous gas mixture.” Subsequently, identif GmbH applies an additional layer of thin metal, which generates highly specific brilliant color effects. Due to the underlying fluorocarbon layer, the color change effect can be copied only with extreme difficulty, and the label is more easily readable by machine.

The technique is not only suitable for the coating of polymeric films. In a further project with CEROBEAR GmbH the Fraunhofer IGB researchers coated antifriction bearings made of ceramic for the Space Shuttle and motor sport applications. The bearings’ friction values could clearly be reduced through the nano-layers. The new technique can be used also with textiles and numerous other types of material. The plasma process parameters can be adjusted in such a way that different characteristics are achieved. Textiles can be rendered water-impermeable or surfaces given an anti-bacterial effect.

The Fraunhofer scientists are currently transferring their know-how to their different industrial partners. Prototypes of the new safety labels and antifriction bearings will be presented at K 2007, the international trade fair for plastics and rubber, to be held in Düsseldorf on October 24 through 31 (Booth E91, Hall 3).