Hybrid ADDvance® – Creating Long Lasting Confidence

Cotton banknotes are still now the substrate for 95% of the world´s banknotes and continue to be the basis for substrate-embedded innovation which has harnessed both security and durability. We know durability of cotton substrates has been a growing requirement of issuers seeking a more cost-effective solution, so these benefits are all now packaged in Hybrid ADDvance®.

Let´s briefly see how this innovation developed. Cotton banknotes already have high strength due to the cotton fibres, but this also attracts moisture and dirt through circulation. Significant improvements have been made by adding plastic fibres and special coatings. There are many references for this, but perhaps amongst the best known is the ECB, achieving over 50% lifetime increase through varnishing. However, there are other ways to increase lifetime in circulation.

Advances in substrate is the key, and Hybrid ADDvance also provides a design platform for the higher denominations. It protects all security elements – watermarks, foil elements and patches, threads and security fibres.

The protective film is about 6 microns thick, but forms a major barrier against moisture and dirt. Then an ink receptive layer is applied in several layers. The structure is one of the technological keys of Hybrid ADDvance, which ensures that the foil elements that are embedded into the substrate retain their brilliance and do not become cloudy due to the layers above.

This is the finished substrate, which is then printed like a normal banknote. Subsequently it is varnished to protect the banknote print and prevent colour abrasion.

How long do Hybrid notes circulate compared to cotton notes? The general result is a circulation time around three times longer than that of pure cotton notes, depending on the denomination. This finding was proven in a dedicated machine-based observation of the cash cycle in Jamaica.

In the development phase of new products, one has to rely on laboratory methods to verify the success of the development. Extreme tests are usually conducted to efficiently prove the robustness of the substrate. An essential aspect is the simulation of wear by the human hand. The slow wear that takes place in circulation is simulated in the laboratory by synthetic sweat and mechanical-chemical stress.

In developing Hybrid ADDvance, the key goal was to integrate high-quality security foils in such a way that they retain their optical brilliance until the end of the banknote's life, and can thus be authenticated. The fine structures are usually damaged early when exposed to unusually high stresses, especially through perspiration and mechanical strain, and so far this problem has not been solved for many central banks. For the laboratory test, a cotton note with LEAD serves as a reference. If the note is soaked with synthetic sweat (Iso Norm), the strip is rapidly attacked from both sides, the metal layer corrodes and decomposes very quickly under these extreme conditions. In contrast, the fully embedded foil element in Hybrid ADDvance remained completely intact for several weeks.