| abstract |
The present invention relates to a method for producing a security film (2) with characters (11) recognizable in transmitted light and / or incident light by printing a substrate (3, 13) with an ink (4) in the form of the characters (11) to be produced, Applying a coating (7) on the side of the substrate (3, 13) printed with the printing ink (4), and removing the printing ink (4) and the regions of the coating (7) lying above the printing ink by washing with a washing liquid, then that the characters (11) are formed. According to the invention, a printing ink (4) is used which comprises at least one reactive constituent and / or precursor of a reactive constituent which, upon contact with the wash liquor, causes a process which results in the fracturing of the areas of the coating above the ink (4), and / or a reactive ingredient which when irradiated or heated causes a process leading to rupture of the areas of the coating overlying the ink (4). By means of the printing ink it is possible in particular to remove very thick coatings and layer structures from a plurality of layers. The invention further relates to a security film (2) produced by the process according to the invention, the use of the security film for product security as well as value documents which are provided with the security film (2), and a process for producing such value documents. |