Patent EP-1972462-A3 (EP)
Inventor: KROMBHOLZ MARKUS DR
IPC: D21H21/42
Filed: 2007-12-21
Abstract: The method for producing a safety foil for a valuable document e.g. check, comprises printing a side of a substrate with a printing ink (4) in the form of characters to be produced, applying a coating on the printed side of the substrate, and removing the printing ink and the area of the coating lying over the printing ink by washing with an aqueous washing liquid, so that slots are formed in the form of characters in the coating. The safety foil has visually recognizable characters in the transmitted light and in the reflected light. The printing ink contains a filler and a binding agent. The method for producing a safety foil for a valuable document e.g. check, comprises printing a side of a substrate with a printing ink (4) in the form of characters to be produced, applying a coating on the printed side of the substrate, and removing the printing ink and the area of the coating lying over the printing ink by washing with an aqueous washing liquid, so that slots are formed in the form of characters in the coating. The safety foil has visually recognizable characters in the transmitted light and in the reflected light. The printing ink contains a filler, a binding agent and a reactive component and/or a precursor of a reactive component, which causes a process during contacting with the washing liquid and/or during irradiation or heating, where the process leads to crack the area of the coating during contacting and/or irradiation or heating. The reactive component is the filler. The reactive component and/or the precursor of the reactive component is a first component (5') of a two-component gassing system that consists of the first component and a second component (5''). The first component is contained in the printing ink and the second component is contained in the washing liquid. The first- and/or the second component are a mixture of reaction agent. The two-component gassing system produces carbon dioxide. The first component is a catonic photo-initiator that adjusts an acid during irradiation with a pre-determined wavelength. A portion of the first component or the second component is 10-20 wt.% at the printing ink. The components are used in stoichiometric quantities related to the functional groups. The reactive component of the printing ink that causes the process during irradiation or heating is a foaming agent or swelling agent. The printing ink contains the first component, the swelling agent and/or foaming agent. The printing ink has 15-30 wt.% of filler, 5-15 wt.% of binding agent, 50-80 wt.% of water, and 50-80 wt.% of water-free solvent. The coating is a metal layer (7) or metal containing layer. A further layer is applied on to the coating over the side of the substrate printed with the printing ink. A magnetic ink layer, interference pigment layer, liquid crystal layer, a metal layer and a chromatic color for the preservation of precious metal optics are applied as the further layer. The area of the coating and the further layers is jointly removed by washing register during the removal of printing ink. The coating and the further layers are applied in a total thickness of 1 nm up to 15 mu m. The printing of the substrate takes place in an intaglio printing process. The washing of the printing ink is supported by mechanical means. Independent claims are included for: (1) safety foil for attaching at or for partially bringing in a valuable document such as bank note, a check or an identification card; (2) valuable document; and (3) a process for manufacturing a valuable document.