EP2886343B1 - Method for producing a valuable document, valuable document so obtained and security element obtainable therefrom and device for carrying out the method - Google Patents

Description

The invention relates to a method for producing a value document, in particular a banknote, and a device for carrying out the method.

Value documents within the meaning of the invention include, among others, banknotes, stocks, bonds, certificates, vouchers, checks, air tickets, high-quality admission tickets, labels for product security, credit or debit cards, but also other documents that are subject to forgery such as passports, identity cards or other identity documents.

During their circulation, value documents, such as banknotes, are exposed to heavy burdens of various kinds, which limit their orbital period. The circulation period of a banknote depends essentially on its demand. Certain denominations are preferably used in commerce and thus have a shorter circulation time due to the greater exposure to environmental influences. One cause of the limitation of the circulation time is mechanical stress due to abrasion, folding or creasing. The main cause of the limited circulation time of banknotes is their premature pollution. Since the paper used for banknotes is very porous, it has a large surface area and a high surface roughness. The surface roughness favors dirt deposits considerably compared to a smooth surface. Dirt can be liquid or solid, and liquid dirt in turn can be hydrophobic or hydrophilic.

There is a need to protect value documents, and in particular the heavily used banknotes, against soiling and contamination of any kind, thereby increasing the circulation time.

Numerous attempts have been made to extend the life of banknotes. For example, it has been proposed to make banknotes entirely from a plastic substrate (see, for example, US Pat AU 488,652 ). In the publication EP 0 256170 B2 It has been proposed to provide printed banknotes with a dirt-repellent protective layer which contains cellulose ester or cellulose ether to a lesser extent and to a lesser extent micronized wax and which is applied to the banknotes over the entire area. The micronized wax is thereby dispersed by kneading or mixing with oil, a colorant or a mixture thereof.

Special importance is also attached to the optical properties of valuable document coatings. The coatings should preferably provide a matte surface appearance, since dull coatings do not adversely affect the visual appearance of a value document, as opposed to very smooth coatings, provide a better grip to the document of value when dropped, stacked and gripped, thereby preventing slippage of the stacked sheets Avoid transport processes (influenced by static and sliding friction), and also facilitate the mechanical inspection of the safety elements. A security element, which is surrounded by a matt coating, is easier to detect because of the much lower reflections from optical sensors or is not disturbed by highlights.

Value documents with paper substrate are often printed by intaglio printing. Due to the high pressure with which the substrate is pressed against the printing plate in this process, the paper surface in the non-engraved, d. H. non-ink-bearing areas of the printing plate strongly compressed and smoothed. As a result, an undesirable gloss can be produced on the paper substrate, which is to be reduced again by a matt coating applied afterwards.

While it is generally desirable to give value documents a rather dull surface appearance, the visual appeal of tamper-evident means must not be compromised by a dull coating, i. toned down. In certain cases, it may even be very desirable to visually emphasize the anti-counterfeiting means to specifically direct a viewer's attention to it. Hiding under a matt coating would then be very counterproductive, but the anti-counterfeiting agent should be visually highlighted and emphasized by the strongest possible coating.

With regard to the optimization of the gloss, it has proven useful, before applying a high-gloss lacquer, first to coat a paper substrate with a first lacquer layer, e.g. a matte finish, and to seal the substrate surface. In this way, gloss losses can be avoided, which are caused by the fact that the high-gloss lacquer applied to the substrate penetrates or repels the substrate.

Value documents whose surfaces have both matte and glossy areas (so-called matt / gloss effects) can be made easier Be adjusted by printing techniques or by gluing high-gloss films.

The WO 2012/079674 A1 describes a method of producing three-dimensional patterns in coatings containing flaky effect pigments, patterned coatings prepared therewith, and their use in decorative and security products.

The DE 101 24 630 A1 describes a security, in particular a banknote, and a method for its production. The security has a security element and a protective lacquer layer formed from a matt lacquer, which is recessed in the area of the security element. If necessary, the recessed area is provided with a protective lacquer layer formed from a gloss varnish.

Based on this, the object of the invention is to provide value documents which are optimized in terms of their gloss and, in particular, have an increased protection against counterfeiting. The value documents should in particular have an increased circulation time.

This object is achieved by the feature combinations defined in the independent claims. The dependent claims indicate advantageous embodiments of the invention.

Summary of the invention

1. 1. A first aspect of the invention relates to a method for producing a value document, in particular a banknote, according to claim 1.
   The obtained, completely crosslinked by means of UV light, effect pigments containing color layer may also have a dirt-repellent effect, in particular due to their material properties.
   In particular, the generated three-dimensional embossing pattern may be in a see-through window area of the value document substrate (eg, a see-through window area may be created on a paper substrate through a recess, with the area of the recess being provided with a foil; alternatively, a see-through window area may be created by placing a substrate on plastic Base having an opaque ink accepting layer except for the see-through area). More particularly, the three-dimensional embossed structure can be based on iriodin pigments. Such pigments have a white-silvery color, so that the three-dimensional embossed structure is recognizable especially when viewed against a black background.
   In order to improve the transfer of the effect pigment-containing ink layer from the printing plate to the substrate, it is advantageous to equip the printing plate with microstructures. Such printing plates with microstructures are produced, for example, by the company Rudolf Reproflex GmbH or by Kodak (by Kodak under the trade name "DigiCap NX"). The microstructures, which ultimately represent a grid, cause a more uniform, more stable color transfer to the substrate via the enlargement of the surface and thus lead to an increase in the effect.
2. 2. A preferred embodiment relates to the method according to paragraph 1, which between steps b) and c) the additional step of incomplete crosslinking of the applied to the value document substrate UV-crosslinkable, effect pigments containing color layer by means of a UV drying device in order to modify in this way the viscosity of the ink layer and the flow properties of the not yet fully crosslinked ink layer after the introduction of the three-dimensional embossed structure.
3. 3. A further preferred embodiment relates to the method according to one of the paragraphs 1 or 2, which has the additional step of applying a primer layer between the steps a) and b), which is preferably based on a visually invisible paint or on a visually recognizable color and particularly preferably contains inorganic colored pigments, organic dyes, carbon black or magnetic pigments.
4. 4. A further preferred embodiment relates to the method according to paragraph 3, wherein the primer layer is applied by means of offset printing, flexographic printing, screen printing, inkjet printing or gravure printing on the substrate.
5. 5. A further preferred embodiment relates to the method according to any one of paragraphs 1 to 4, wherein the effect pigments used in step b) flowable, UV-crosslinkable ink layer of the group consisting of pearlescent pigments, metallic effect pigments, interference pigments, multilayer pigments with transparent or transparent and opaque layers, holographic pigments, BiOCl pigments and liquid crystal pigments.
6. 6. A further preferred embodiment relates to the method according to any one of paragraphs 1 to 5, wherein the used in step c) paint to form the soil-repellent coating is a water-based paint, a UV-coating, which is in particular free-radically or cationically curing, or is a water based varnish with UV reactive components.
7. 7. A second aspect of the invention relates to an apparatus for carrying out the method according to one of the paragraphs 1 to 6 with the features according to claim 7.

Detailed description of the invention

The embossing of printed layers based on effect pigments is known in securities printing. Thus, for example, in intaglio printing, applied to a value document substrate, already through-hardened, OVI® pigments or similar pigments containing color layers can be blind embossed in a subsequent step. Due to the high pressure, the surface of the value document substrate adapts to the engraved surface of the printing form (in particular a intaglio printing plate) used for the blind embossing. The disadvantage of such a method is, inter alia, that the pigments are almost fixed with respect to their spatial orientation within the printing layer, so that a reorientation of the pigments is only possible to a limited extent. Furthermore, for the step of embossing cured print layers, a relatively high pressure and deep engraving are required, which may possibly lead to damage to the value document substrate (in particular paper). Another disadvantage is the Passerschwankungen in intaglio.

The invention is based on the idea of using the second flexographic printing unit of a flexographic printing press not only as a printing unit but also as a stamping unit.

By means of the first flexographic printing unit of the flexographic printing machine, first a UV-crosslinkable color layer containing effect pigments is applied to the value document substrate applied. The color layer preferably has a layer thickness in a range of 4 to 12 μm, particularly preferably a layer thickness in a range of 6 to 10 μm.

By means of an optionally arranged between the first flexographic printing unit and the second flexographic printing unit UV drying device (hereinafter also referred to as "first UV drying device" or as "UV intermediate dryer"), the viscosity of the applied by the first flexographic printing on the value document substrate, Control UV-curable ink layer specifically via the UV output. In particular, incomplete crosslinking (a so-called hardening) of the UV-crosslinkable color coat containing effect pigments takes place on the value document substrate, in order to increase the viscosity of the color layer and make it more easily impressionable. In particular, the UV intermediate dryer is an LED dryer with a power of 1 to 8 watts / cm ² . Such a dryer module does not require a mechanical shutter, so there are also relatively small designs. The hardening of the color layer can take place from the front side, or preferably from the rear side, through the substrate. Curing from the back side has the advantage of reducing the impact of the ink layer into the substrate. In particular, the back side of the substrate may partially comprise a UV-absorbing layer, eg an opaque white layer. In this way, the power of the UV radiation can be modulated.

In the second flexographic printing unit, an exact or register-accurate embossing of the ink layer applied by means of the first flexographic printing unit takes place in order to produce a relief effect in this way. In the second flexographic printing unit, in addition to the embossing of the ink layer, the application of a Dirt-repellent coating performed on the value document substrate. The dirt-repellent coating is applied to the substrate as "complete" to the color layer so that no overlap occurs between the UV-crosslinkable color layer and the dirt-repellent coating. The soil-repellent coating preferably has a layer thickness in a range of 1.5 to 3 μm.

By means of the method according to the invention, the production of the relief coating can be effected in a cost-effective manner in an "in-line process" together with the production of the dirt-repellent coating.

The flexographic printing plate used in the second flexo printing unit can additionally have a color or lacquer-repellent coating on its surface in the embossing area in order to reduce the contamination.

After the embossing step, the complete curing of the embossed, UV-curable ink layer takes place by means of a further UV drying device (which is also referred to below as "second UV drying device" or as "UV end drier").

The production method according to the invention makes it possible to provide strong embossings (which are also referred to below as "macroscopic structure" or "macroscopic embossing") within the UV-curable ink layer, in order to produce a relief effect in this way. The three-dimensional effect created by the pits present in the ink layer is visually enhanced by the use of effect pigments. This is due, among other things, to the fact that in the embossing step not only the color layer is displaced, but also the spatial orientation of the effect pigments is changed.

The flow (i.e., the spatial retraction) of the flowable ink layer is believed to be faster than reorientation of the effect pigment so that the embossing information remains discernible despite a partial leveling of the ink layer due to the not yet complete reorientation of the effect pigment. The course of the color layer and the fixation of the spatial orientation of the effect pigments can be controlled by the optional UV intermediate dryer.

The macroscopic embossing introduced into the UV-crosslinkable ink layer is in particular an identification in the form of (line) patterns, characters, numerals or the like. The embossed marking can have a meaning connection to existing motifs on a value document.

The UV-crosslinkable ink may also contain (machine-readable) feature substances, e.g. luminescent, magnetic and / or IR-absorbing feature substances. If the relief lacquer produced by means of the UV-crosslinkable ink contains additional machine-readable feature substances, then the feature intensity (for example the intensity of the luminescence emission) correlates with the height of the three-dimensional relief lacquer. In this way, the three-dimensional structure is also machine-readable.

In order to optimize the embossing effect, the value document substrate can already be printed with a primer layer (or precoat) prior to the step of applying the UV-curable ink layer by means of the first flexographic printing unit, which effects a smoothing of the substrate and thus a repelling of the UV-crosslinkable ink layer reduced in the substrate. The primer layer can be based, for example, on a visually invisible lacquer or on a visually recognizable color. The primer layer can in particular inorganic colored pigments, organic dyes, carbon black or magnetic pigments. Primer layers containing colored pigments can be used to optimize the contrast of the three-dimensional color layer present above the primer. The primer imprint can be made over the whole area or only in a partial area on the substrate. The primer can be applied to the substrate in offset printing, flexographic printing, screen printing, inkjet printing or gravure printing, for example. Furthermore, the primer layer may feature feature substances, for example luminescent, magnetic and / or IR-absorbing feature substances. The primer may also contain effect pigments.

The printing of the UV-crosslinkable ink layer can in particular be adapted or made in register with the imprint of the primer layer. This procedure is e.g. makes sense if the primer form in an "in-line process" is carried out together with the printing of a Relieflack generating UV-crosslinkable ink layer.

The UV-crosslinkable ink layer used in the process according to the invention is based on an effect pigment / binder combination. Particularly suitable as effect pigments are flake-form effect pigments, more particularly pearlescent pigments, metallic effect pigments, interference pigments, multilayer pigments with transparent or transparent and opaque layers, holographic pigments, BiOCl pigments (BiOCl = bismuth chloride oxide) or liquid crystal pigments or LCP pigments (LCP = liquid crystal polymer). to get voted.

Interference pigments typically have a thin film structure that includes a reflective layer, a partially transparent layer, and one or more intervening dielectric spacer layers. These are based, for example, on mica, on SiO ₂ or on Al ₂ O ₃ . Such interference layers are referred to as one or more layers according to the number of dielectric layers. Printing inks with pigments of such thin-layer interference layers are sold, for example, under the name Iriodin® (monolayer) or Colorcrypt® (multilayer) by Merck KGaA. Printing inks with multilayer interference-layer pigments are also sold under the name OVI® by SICPA.

A subgroup of the interference layer pigments are cholesteric or other liquid crystals which may also be used. These are, for example, as liquid-crystalline silicone polymers or as pigments in so-called STEP® shades ("Shimmery Twin Effect Protection"). Pigments based on liquid-crystalline polymers are known, for example, from US Pat WO 2008/000755 A1 known. Liquid crystal UV screen printing inks are available, inter alia, from Merck.

The UV-crosslinkable printing ink used according to the invention can moreover be applied to the in the WO 2011/064162 A2 Color effect effect pigment compositions described are based. The pigments have a longest dimension of edge length from end-to-end in a range of 15 nm to 1000 nm and are based on a transition metal selected from the group consisting of Cu, Ag, Au, Zn , Cd, Ti, Cr, Mn, Fe, Co, Ni, Ru, Rh, Pd, Os, Ir and Pt. The transition metal is preferably Ag. The aspect ratio (ie the ratio of the longest end-to-end dimension in terms of thickness) is at least 1.5, more preferably in the range of 1.5 to 300. The ratio of the binder to metal pigment is below 10: 1, especially below 5: 1. Depending on the choice of the aspect ratio of the pigment, its As long as the end-to-end dimension and the pigment / binder ratio are adjusted, the color can be seen in transmission and the color when viewed in reflection (eg blue in transmission and silver, gold, bronze, copper or violet in addition, violet, magenta, pink, green or brown in transmission and various colors in reflection, which depend on the choice of pigment / binder ratio). Colors with gold / blue color change between reflection and transmission (in other words, between incident light and transmitted light observation) are, for example, in Examples 1, 2 and 3 in Table 1 of FIG WO 2011/064162 A2 called. Further, Example 4 shows a color with gold / violet color change, Example 5 a color with green-gold / magenta color change, Example 7 a color with violet / green color change and Example 8 a color with silver / opaque color change.

The UV-crosslinkable printing ink used according to the invention can moreover be applied to the in the WO 2005/051675 A2 (See in particular the description on page 11, line 10, to page 12, penultimate paragraph) based metal pigment compositions. The pigments are based on a metal, which is preferably selected from the group consisting of aluminum, stainless steel, nichrome, gold, silver, platinum and copper. The metal is particularly preferably aluminum, wherein the average particle diameter is preferably in a range of 8 to 15 μm, more preferably in a range of 9 to 10 μm, measured with a Coulter LS130 laser diffraction granulometer. Such ink allows the provision of a "silver" mirror layer. In addition, the metal pigment compositions (eg, yellow) may be colored.

1. 1) Der Primer enthält einen im langwelligen UV-Bereich anregbaren lumineszierenden Merkmalsstoff. Der Relieflack enthält einen im kurzwelligen UV-Bereich anregbaren lumineszierenden Merkmallsstoff. Auf diese Weise kann in Abhängigkeit von der Anregungswellenlänge, dem Druckmuster der Primerschicht und des Relieflacks und der (Relief-)Höhe des Relieflacks eine unterschiedliche Bildinformation erzeugt werden.
2. 2) Der Primer enthält einen im kurzwelligen UV-Bereich anregbaren lumineszierenden Merkmalsstoff. Der Relieflack enthält ebenfalls einen im kurzwelligen UV-Bereich anregbaren lumineszierenden Merkmallsstoff. Auf diese Weise kann in Abhängigkeit von der Schichtstärke und der (Relief-)Höhe des Relieflacks die von der Primerschicht ausgehende Lumineszenz-Emission mehr oder weniger verstärkt werden. Die von der Primerschicht ausgehende Lumineszenz-Emission wird darüber hinaus von der Orientierung der im Relieflack vorhandenen Effektpigmente beeinflusst, d.h. mehr oder weniger stark abgeschwächt.

If both the primer layer and the UV-crosslinkable ink used for the production of the relief coating contain feature substances (eg luminescent, magnetic and / or IR-absorbing feature substances), the associated measurement signal intensities may be similar, so that the measurement signal Intensity is enhanced, or different. Hereinafter, preferred combinations are named:

1. 1) The primer contains a stimulable in the long-wave UV range luminescent feature substance. The relief lacquer contains a stimulable in the short-wave UV range luminescent Merkmallsstoff. In this way, different image information can be generated depending on the excitation wavelength, the print pattern of the primer layer and the relief and the (relief) height of the relief.
2. 2) The primer contains a stimulable in the short-wave UV range luminescent feature substance. The relief lacquer likewise contains a luminescent feature substance which can be excited in the short-wave UV range. In this way, depending on the layer thickness and the (relief) height of the relief coating, the luminescence emission emanating from the primer layer can be more or less intensified. The emanating from the primer layer luminescence emission is also influenced by the orientation of the present in the Relieflack effect pigments, ie more or less greatly attenuated.

The varnish for forming the soil-repellent coating may in particular be a water-based varnish, a UV varnish (which in particular is free-radically or cationically curable) or a water-based varnish with UV-reactive components. UV-curing coatings are characterized by a high physical and chemical resistance and are very abrasion. Radical crosslinking UV lacquers are preferably suitable. Free-radically crosslinking compositions are based, for example, on acrylic acid esters. It will be understood that suitable photoinitiators must be included in each case and that the compositions may contain the usual adjuvants known to those skilled in the art. It is preferred that the antisoiling coating additionally comprises silicone resins and / or waxes to improve antisoiling properties. In addition, adjuvants may be included, for example, coalescing agents, leveling agents, wetting agents, defoaming agents, viscosity modifiers, dispersing aids, and diluents. Also preferably non-recognizable feature substances, such as luminescent substances, may be included in the composition.

The value document substrate which is provided with UV-crosslinkable ink according to the method according to the invention can be in particular a security paper. A security paper is understood to be a value document that can not yet be processed. The term security paper also includes paper-like substrates, for example plastic or polymer substrates, or paper / plastic multilayer substrates, such as a plastic / paper / plastic substrate or a paper / plastic / paper substrate. Under a plastic / paper / plastic substrate is a substrate with a paper center layer to understand, which is provided on both sides with a plastic layer or foil (see the WO 2004/028825 A2 ). A paper / plastic / paper substrate is out of the WO 2006/066431 A1 known.

The inventive method is not only suitable for the production of value document substrates, but also for the production of security films and security elements. A security element is usually provided with a functional layer having a security feature, for example an optically variable coating. It is particularly useful if the security element is adhered by means of an adhesive, for example by means of a heat seal lacquer, on the valuables or the security paper. Such a security element is eg a patch. The security element is usually provided together with further security elements on a carrier (or carrier substrate) serving, strip-shaped continuous foil and transmitted from there to the surface of a security paper or a valuable item. Since the carrier film is removed in some cases from the surface of the security element in the application of the security element on the security paper or on the valuables, often the term (endless) transfer film or instead of the term endless film instead of the term endless film Security element used the term transfer element. A strip-shaped endless film is provided as a roll product, that is to say wound up as an endless belt on a roll, wherein the endless film is of course not endless and thus infinitely long, but in particular has a length in the range of kilometers. Machines for applying security elements to the surface of a security paper or a valuable item are commercially available, eg OptiNota H® from König & Bauer AG. Such a device allows the exact fit or register accurate application of security elements in the form of film strips on paper sheets.

The method according to the invention is also suitable for providing security documents, in particular banknotes, which are provided with a see-through security feature, such as a see-through window.

The invention will be explained below with reference to preferred embodiments in conjunction with the accompanying figures, in the representation of a scale and proportionate reproduction has been omitted in order to increase the clarity.

Fig. 1

eine schematische Querschnittansicht eines mit einem Primer-Aufdruck versehenen Wertdokumentsubstrats;

Fig. 2

eine schematische Querschnittansicht eines mit einem Primer-Aufdruck versehenen Wertdokumentsubstrats, das zusätzlich eine UV-vernetzbare, Effektpigmente enthaltende Farbschicht aufweist;

Fig. 3

eine schematische Querschnittansicht eines mit einem Primer-Aufdruck versehenen Wertdokumentsubstrats, wobei die UV-vernetzbare, Effektpigmente enthaltende Farbschicht eine makroskopische Verprägung aufweist und somit einen Relieflack bildet; oberhalb des Substrats (und des gegebenenfalls vorhandenen Primers) befindet sich außerhalb des Bereiches des Relieflacks eine Schmutz-abweisende Beschichtung;

Fig. 4

eine schematische Querschnittansicht einer im zweiten Flexodruckwerk verwendbaren Druckplatte gemäß einem ersten Ausführungsbeispiel, das nicht Teil der Erfindung ist, sondern das Verständnis der Erfindung erleichtert;

Fig. 5

eine schematische Querschnittansicht einer im zweiten Flexodruckwerk verwendbaren Druckplatte gemäß einem zweiten Ausführungsbeispiel;

Fig. 6

eine schematische Querschnittansicht der Druckplatte der Figur 4, die nicht Teil der Erfindung ist, nach der Einfärbung mit Lack zur Erzeugung der Schmutz-abweisenden Beschichtung;

Fig. 7

eine schematische Querschnittansicht der Druckplatte der Figur 5 nach der Einfärbung mit Lack zur Erzeugung der Schmutzabweisenden Beschichtung;

Fig. 8

eine schematische Querschnittansicht des Wertdokumentsubstrats der Figur 3, wobei der Relieflack einen starken Verlauf aufweist;

Fig. 9

eine schematische Querschnittansicht des Wertdokumentsubstrats der Figur 3, wobei der Relieflack einen geringen Verlauf aufweist.

Show it:

Fig. 1

a schematic cross-sectional view of a provided with a primer printing value document substrate;

Fig. 2

a schematic cross-sectional view of a provided with a primer print value document substrate, which additionally has a UV-crosslinkable, effect pigments containing color layer;

Fig. 3

a schematic cross-sectional view of a provided with a primer print value document substrate, wherein the UV-crosslinkable, effect pigments containing ink layer has a macroscopic embossment and thus forms a relief varnish; above the substrate (and the optional primer) is located outside the area of the Relieflacks a dirt-repellent coating;

Fig. 4

a schematic cross-sectional view of a usable in the second flexographic printing plate according to a first embodiment, which is not part of the invention, but facilitates the understanding of the invention;

Fig. 5

a schematic cross-sectional view of a usable in the second flexographic printing plate according to a second embodiment;

Fig. 6

a schematic cross-sectional view of the pressure plate of FIG. 4 which is not part of the invention after coloring with varnish to produce the soil-repellent coating;

Fig. 7

a schematic cross-sectional view of the pressure plate of FIG. 5 after coloring with lacquer to produce the stain-resistant coating;

Fig. 8

a schematic cross-sectional view of the value document substrate of FIG. 3 , wherein the relief lacquer has a strong course;

Fig. 9

a schematic cross-sectional view of the value document substrate of FIG. 3 , wherein the relief lacquer has a low profile.

Fig. 1 shows a schematic cross-sectional view of a provided with a primer imprint 2 value document substrate 1, which is formed in the present case of paper. The primer imprint 2 contains a colored ink and was produced by offset printing. The primer imprint 2 is structured and forms a recognizable to the viewer information.

Fig. 2 shows a schematic cross-sectional view of a provided with a primer imprint 2 value document substrate 1, which additionally comprises a UV-curable, containing iriodin pigments ink layer 3. The color layer 3 has a layer thickness in a range of 7 microns. The ink layer 3 was produced by means of the first flexographic printing unit of a flexographic printing machine. The color layer may optionally be incompletely crosslinked (ie, cured or polymerized) in a subsequent step by means of a UV drying device, in order to increase the viscosity and improve the embossability of the color layer, or in other words to reduce the course. In the present case, the imprint of the ink layer 3 was not adapted to the structure of the primer imprint 2, ie the primer 2 is only partially provided with the ink layer 3.

Fig. 3 shows a schematic cross-sectional view of a provided with a primer imprint 2 value document substrate 1, wherein the UV-crosslinkable, Iriodin pigments containing ink layer has a macroscopic embossing and thus forms a relief paint or 3-D paint 31. The embossing was carried out by means of the second flexographic printing unit of a flexographic printing machine. The adhesion of ink to the flexographic printing plate serving as embossing tool can be even more reduced or avoided by a suitable adjustment of the degree of hardening of the ink layer 3 when passing through the optional UV drying device. In the second flexographic printing unit, in addition to embossing the ink layer 3, the application of a dirt-repellent coating 4 to the value document substrate 1 is carried out at the same time. In this case, the dirt-repellent coating 4 is applied "completing" to the ink layer 3 (or 31) on the substrate so that no overlap occurs between the UV-crosslinkable ink layer 3 (or 31) and the dirt-repellent coating 4. The dirt-repellent coating 4 has a layer thickness of 2 μm.

Fig. 4 shows a schematic cross-sectional view of a usable in the second flexographic printing plate flexographic printing plate 5 according to a first embodiment, which is not part of the invention, but facilitates the understanding of the invention. The flexographic printing plate 5 contains the two areas 51 and 52, of which the area 51, the embossing information for generating the relief in the relief 31 of the FIG. 3 forms and the area 52 forms the inking area for producing the soil-repellent coating 4 of Figure 3. The two areas 51 and 52 of the flexographic printing plate 5 have the same height.

Fig. 5 shows a schematic cross-sectional view of a usable in the second flexographic printing plate flexographic printing plate 6 according to a second embodiment. The flexographic printing plate 6 includes the two portions 61 and 62, of which the recessed portion 61, the embossing information for creating the relief in the relief 31 of the FIG. 3 forms and the raised portion 62, the inking area to produce the dirt-repellent coating 4 of FIG. 3 forms. The area 61 of the printing plate has a reduced height compared to the area 62. In other words, in the printing plate, the area forming the embossing information for creating the relief in the 3-D paint is lowered.

Fig. 6 shows a schematic cross-sectional view of the non-inventive printing plate of FIG. 4 after coloring with varnish to produce the soil-repellent coating (reference number 4 in the FIG. 3 ). How to use the FIG. 6 was able to recognize both the area 51, and the area 52 of in FIG. 4 shown printing plate 5 evenly dyed with (anti-soiling) paint to form in this way the paint-colored areas 71 and 72 of the printing plate.

Fig. 7 shows a schematic cross-sectional view of the pressure plate of FIG. 5 after coloring with varnish to produce the soil-repellent coating (reference number 4 in the FIG. 3 ). How to use the FIG. 7 could not recognize the recessed area 61, but only the elevated area 62 of the FIG. 5 shown printing plate 6 with (Antischmutzbeschichtungs-) paint 82 dyed.

Starting from the in FIG. 2 The value document shown can be used for the step of generating the in FIG. 3 shown, a Relieflack 31 and an anti-contamination coating 4 having value document substrate in FIG. 7 shown flexographic printing plate can be used. In the FIG. 7 shown flexographic printing plate is used because in the area 61 of the printing plate, which forms the embossing information and is used for the embossing of the UV-crosslinkable ink layer 3, no possibly interfering anti-fouling coating is present.

Fig. 8 shows a schematic cross-sectional view of the value document substrate of FIG. 3 after the step of finally drying by means of a UV drying device. Based on FIG. 8 It can be seen that after embossing the UV-curable ink layer (reference number 31 in FIG. 3 ) a relatively strong course of 3-D paint occurred. In other words, the 3-D enamel 311 has "recovered" from the embossment at the bottom and retreated to create a "soft" relief relief. The intensity of such a course depends, among other things, on the viscosity of the UV-curable varnish and the time interval between the embossing step and the subsequent UV-curing step.

Fig. 9 shows a schematic cross-sectional view of the value document substrate of FIG. 3 after the step of finally drying by means of a UV drying device. Based on FIG. 9 It can be seen that after embossing the UV-curable ink layer (reference number 31 in FIG. 3 ) a relatively weak or low profile of the 3-D paint occurred. In other words, the 3-D varnish 312 has "recovered" only slightly from the embossment at the bottom and retracted slightly to create a "hard" image relief.

Example 1: a) primer (optional)

On security paper for the production of banknotes, a color ink was first applied in offset printing. The chromatic color enhances the 3-D effect.

b) Flexographic printing unit 1

Subsequently, in a first flexographic printing unit of a flexographic printing machine, a UV varnish was applied to the value document substrate by means of an anilox roller (scoop volume: 20 cm ³ / m ² ). The paint application was 7 microns. The UV varnish contained 7% by weight of iriodin pigments. Optionally, silicone oils may be added to the UV varnish to reduce strike-off of the varnish into the substrate and, moreover, to reduce fouling of the embossed flexographic printing plate. The UV varnish had a viscosity of 40 sec. DIN CUP 4 cup. In order to improve the course of the UV varnish, preference may be given to working with a varnish temperature of 30 to 40 ° C. The elevated temperature has a viscosity-reducing effect. Suitable UV lacquers are known from the packaging sector and are available, for example, from Weilburger or Schmid-Rhyner.

c) flexo printing unit 2

In the wet (or uncured) UV varnish, a structure was imprinted. The impressing led to a partial displacement of the UV varnish.

The embossing printing plate used was a flexographic printing plate of the "3D Evolution" type from Reproflex.

The paint composition for the formation of the anti-soiling coating will be explained below with reference to an example recipe. It is a radically curing UV varnish.

Depending on the desired rheological properties, the degree of gloss and the elasticity of the components may vary in their proportions and quality. component Manufacturer Function / chemical name Wt .-% Laromer PE 55 F BASF polyester 24.5 Ebecryl 83 Cytec Amine mod. polyester 20.0 Laromer TPGDA BASF UV thinner, tripropylene glycol diacrylate 12.0 Laromer HDDA BASF UV thinners 12.3 Tego Dispers 655 Evonik Wetting and dispersing additive 2.0 Calciumcaronat OMYA matting agent 20.0 Ebecryl P116 Cytec catalyst 4.0 Tego wheel 2300 Evonik Wetting agent 1.0 Tego Airex 920 Evonik defoamers 1.0 Irgacure 1173 BASF photoinitiator 3.0 Irgacure 819 BASF photoinitiator 0.2 TOTAL 100

Claims (7)

1. A method for manufacturing a value document, in particular a banknote, comprising

   a) making available a value document substrate (1);

   b) applying a flowable, UV-crosslinkable ink layer (3) containing effect pigments to the value document substrate by means of a first flexographic printing unit;

   c) bringing into contact the value document substrate (1) with a flexographic printing plate (6) within a second flexographic printing unit, wherein the flexographic printing plate (6) has a printing plate region which is suitable for embossing the UV-crosslinkable ink layer (3) containing effect pigments that has been applied to the value document substrate (1), and has at least one further printing plate region which is supplied with a lacquer for forming an dirt-repellent coating (4) to produce a value document substrate (1) in this manner having a UV-crosslinkable ink layer (3) containing effect pigments which is supplied with a three-dimensional embossed structure (31, 311, 312) and having a dirt-repellent coating (4) outside of the region of the ink layer (3);

   e) the complete crosslinking by means of a UV drying device of the UV-crosslinkable ink layer (3) containing effect pigments and supplied with a three-dimensional embossed structure (31, 311, 312) that has been applied to the value document substrate (1), wherein

   the flexographic printing plate (6) has two printing plate regions, namely a first, elevated printing plate region (62) which is dyed with the lacquer for forming a dirt-repellent coating (4), and a second, recessed printing plate region which is not dyed with lacquer for forming a dirt-repellent coating (4) and which is adapted to the introduction of a three-dimensional embossed structure (31, 311, 312) into the UV-cross-linkable ink layer (3) containing effect pigments that has been applied to the value document substrate.
2. The method according to claim 1, which has between the steps b) and c) the additional step of the incomplete crosslinking by means of a UV drying device of the UV-crosslinkable ink layer (3) containing effect pigments that has been applied to the value document substrate (1), in order to modify in this manner the viscosity of the ink layer (3) and the flow properties of the not yet completely crosslinked ink layer (3) after introduction of the three-dimensional embossed structure (31, 311, 312).
3. The method according to any one of claims 1 or 2, which has between the steps a) and b) the additional step of applying a primer layer (2) which is preferably based on a visually non-visible lacquer or a visually recognizable ink and which particularly preferably contains inorganic colored pigments, organic dyes, carbon black or magnetic pigments.
4. The method according to claim 3, wherein the primer layer (2) is applied to the substrate by means of offset printing, flexographic printing, screen printing, inkjet printing or gravure printing.
5. The method according to any of claims 1 to 4, wherein the effect pigments of the flowable, UV-crosslinkable ink layer (3) used in the step b) are chosen from the group consisting of pearl luster pigments, metal effect pigments, interference pigments, multilayer pigments with transparent or transparent and opaque layers, holographic pigments, BiOCI pigments and liquid crystal pigments.
6. The method according to any of claims 1 to 5, wherein the lacquer used in step c) for forming the dirt-repellent coating (4) is a water-based lacquer, a UV-lacquer which is radically or cationically curing in particular, or a water-based lacquer with UV-reactive components.
7. An apparatus for carrying out the method according to any of claims 1 to 6, comprising in this order

   - an optional printing unit, in particular an offset, flexographic, screen, inkjet or gravure printing unit, which is adapted to supply a value document substrate with a primer layer;

   - a first flexographic printing unit, which is adapted to apply to the value document substrate (1) optionally supplied with a primer layer (2) a flowable, UV-crosslinkable ink layer (3) containing effect pigments;

   - an optional UV drying device which is adapted to incompletely crosslink the UV-cross-linkable ink layer (3) containing effect pigments that has been applied to the value document substrate (1), in order to modify in this manner the viscosity of the ink layer and the flow properties of the not yet completely crosslinked ink layer after the introduction of a three-dimensional embossed structure;

   - a second flexographic printing unit with a flexographic printing plate (6), which is adapted to bringing into contact with the value document substrate (1) and which has a printing plate region suitable for embossing the UV-crosslinkable ink layer (3) containing effect pigments that has been applied to the value document substrate, and has at least one further printing plate region supplied with a lacquer for forming a dirt-repellent coating (4) in order to produce in this manner a value document substrate (1) having a UV-crosslinkable ink layer (3) which contains effect pigments and which is supplied with a three-dimensional embossed structure (31, 311, 312) and having a dirt-repellent coating (4) outside of the region of the ink layer (3);

   - a UV drying device which is adapted to the complete crosslinking of the UV-crosslinkable ink layer (3) which contains effect pigments and which has been applied to the value document substrate (1) and supplied with a three-dimensional embossed structure (31, 311, 312);

   wherein the flexographic printing plate (6) of the second flexographic printing unit has two printing plate regions, namely a first, elevated printing plate region (62) which is dyed with the lacquer for forming a dirt-repellent coating (4), and a second, recessed printing plate region (61) which is not dyed with lacquer for forming a dirt-repellent coating and which is adapted for the introduction of a three-dimensional embossed structure (31, 311, 312) into the UV-crosslinkable ink layer (3) containing effect pigments that has been applied to the value document substrate (1).

Images