EP3468811B1 - Security element, value document substrate, value document equipped therewith, and production method - Google Patents

Description

The invention relates to a method for producing a value document substrate.

Documents of value, such as banknotes, branded items or identification documents, are often provided with security elements for security purposes, which allow the authenticity of the documents of value to be checked and which at the same time serve as protection against unauthorized reproduction. Security elements with effects that depend on the viewing angle play a special role in securing authenticity, as these cannot be reproduced even with the most modern copiers. The security elements are equipped with optically variable elements that give the viewer a different image impression from different viewing angles and, for example, show a different color or brightness impression and/or a different graphic motif depending on the viewing angle.

In this context, for example, from the WO 2009/080263 A2 It is known to use security elements with multi-layer thin-layer elements, the color impression of which changes for the viewer with the viewing angle (referred to below as the color shift effect). In such thin-film elements, the color-shift effect is based on viewing-angle-dependent interference effects due to multiple reflections in the various sub-layers of the element. The path difference of the light reflected from the different layers depends on the one hand on the optical thickness of a dielectric spacer layer, which defines the distance between a semitransparent absorber layer and a reflection layer, and on the other hand varies with the respective viewing angle. Since the path difference is of the order of the wavelength of the visible of light, an angle-dependent color impression results for the observer due to the extinction and amplification of certain wavelengths. A large number of different color shift effects can be designed by a suitable choice of material and thickness of the dielectric spacer layer.

the WO 2008/061930 A1 describes a method for forming an optically variable image on a substrate comprising applying a curable compound or composition to at least a portion of the substrate; contacting at least a portion of the curable composition with means for generating an optically variable image; curing the curable compound; and optionally depositing a metallic paint onto at least a portion of the cured composition, wherein the means for generating the optically variable image comprises: a transparent support; a transparent material bearing an optically variable image to be applied thereto; and means to dry or cure a paint.

the U.S. 2013/0003150 A1 describes a security element which can be incorporated into a security document or applied to a security document, comprising: at least a first optical structure which comprises a raster image representing a first pattern; at least a second optical structure that is achromatic and presents a second pattern that is at least partially identical to the first pattern. The dots of the raster image are obtained by perforating, depositing and/or cavities of materials chosen from: metals, metal compounds, alloys, metal paints or metal paints.

the WO 2011/066990 A2 describes a security element for a security paper, document of value or the like, with a carrier that has a surface area that is divided into a large number of pixels, each of which comprises at least one optically effective facet, the plurality of pixels each having a plurality of the optically effective facets with the same orientation per pixel and the facets are oriented in such a way that the surface area can be perceived by a viewer as a surface projecting and/or receding in relation to its actual three-dimensional shape. Furthermore, a production method of a security element for security papers, documents of value or the like is described, in which the surface of a carrier is height-modulated in a surface area in such a way that the surface area is divided into a large number of pixels each having at least one optically effective facet, the majority of Each pixel has a plurality of optically effective facets with the same orientation per pixel and the facets are oriented in such a way that a viewer of the security element produced can perceive the surface area as a surface projecting and/or receding in relation to its actual three-dimensional shape. Furthermore, an embossing tool with an embossing surface is described, with which the shape of the facets of a security element can be embossed into the carrier.

Proceeding from this, the invention is based on the object of specifying a simplified method for producing a value-document substrate with high security against forgery and an attractive visual appearance. A further object is to provide a value document substrate with a high degree of security against forgery and an attractive visual appearance.

These objects are solved by the features of the independent claim. Developments of the invention are the subject matter of the dependent claims.

Summary of the Invention

Method for producing a value document substrate according to claim 1. The dimensions of the structural elements of the diffractive structure are preferably in the order of the light wavelength, more preferably in a range that is greater than 100 nm and less than 1 µm, with a range greater than 300 nm and less than 1 µm is particularly preferred. The dimensions of the structural elements of the micromirror arrangement are preferably in a range that is greater than 1 μm and less than 40 μm, with a range greater than 1 μm and less than 30 μm being particularly preferred. The dimensions of the structural elements of the micromirror arrangement have, for example, a height of up to 15 μm and a lateral extent of up to 30 μm. In the embossing step b2), tactile substrate embossings can preferably also be produced, for example by intaglio printing. Furthermore, it is preferred that both the tactile substrate embossings and the relief structures forming a micromirror arrangement or a diffractive structure are produced in one operation. The wording "produced in one operation" is to be understood in such a way that all embossing structures to be introduced into the substrate, i.e. tactile substrate embossing and micro-optical structures such as micromirror arrays and/or relief structures forming diffractive structures, are formed in a single embossing tool, e.g. an intaglio printing plate or a (intaglio -) Pressure cylinder or steel pressure cylinder, which is used in the production.

DETAILED DESCRIPTION OF THE INVENTION The document of value referred to in the present specification is a banknote, namely a polymer banknote or a foil composite banknote.

According to the invention, a value document substrate is produced by printing.

The inventive method for producing a value document substrate is defined in claim 1.

In this case, step b1) can take place before step b2), or vice versa. In the event that the pigments used are so small that they Adapt relief structures very well, carrying out the embossing step b2) before the step of printing the substrate with the pigments b1) is preferred. If larger pigments are used, preference is given to carrying out the step of printing the substrate with the pigments b1) before the embossing step b2).

The relief structure forming a diffractive structure is in particular a hologram structure. The dimensions of the structural elements of the diffractive structure are preferably in the order of magnitude of the light wavelength, more preferably in a range greater than 100 nm and less than 1 μm, with a range greater than 300 nm and less than 1 μm being particularly preferred.

The relief structure forming a micromirror arrangement is also referred to herein as a micro-optical relief structure. The production of a micro-optical relief structure is known in the prior art (see, for example, WO 2014/060089 A2 ). The dimensions of the structural elements of the micromirror arrangement are preferably in a range that is greater than 1 μm and less than 40 μm, with a range greater than 1 μm and less than 30 μm being particularly preferred. The dimensions of the structural elements of the micromirror arrangement have, for example, a height of up to 15 μm and a lateral extent of up to 30 μm. In this case, both the height and the lateral extent of the structural elements of the micromirror arrangement are preferably greater than 1 μm.

Suitable platelet-shaped metal pigments for producing a reflective layer obtainable by printing are, for example, from WO 2013/186167 A2 , the WO 2010/069823 A1 , the WO 2005/051675 A2 (See, for example, the description on page 11, line 10, to page 12, penultimate paragraph) and the WO 2011/064162 A2 known. The platelet-shaped metal pigments described therein have the advantage that they adapt so well to a substrate with a relief structure, in particular a relief with microstructures and/or nanostructures, that the difference to a conventional metallization obtainable by vapor deposition is almost no longer discernible. The simple, printing-technical production of the reflective layer makes it possible to dispense with complex process steps, such as printing the carrier with a soluble wash ink in the form of a desired recess within the reflective layer to be produced, creating a metallization by vapor deposition and washing off the wash ink together with the one above metallization applied to the wash color.

The printing ink which can be used according to the invention and is based on platelet-shaped metal pigments for producing a reflective layer which can be obtained by printing is preferably based on the WO 2005/051675 A2 (See, for example, the description therein on page 11, line 10 to page 12, penultimate paragraph). The pigments are based on a metal that is preferably selected from the group consisting of aluminum, stainless steel, nichrome, gold, silver, platinum and copper. The metal is particularly preferably aluminum, the mean particle diameter preferably being in a range from 2 to 50 μm, more preferably in a range from 5 to 15 μm, measured with a Coulter LS130 laser diffraction granulometer. Such an ink enables a "silver" mirror layer to be provided. In addition, the metal pigment compositions can be colored (eg yellow).

The effect pigments that can be used according to the invention, which assume a different hue depending on the viewing angle, have in particular an interference layer structure which typically comprises a reflection layer, a partially transparent layer or absorber layer and one or more dielectric spacer layers lying in between. The dielectric spacer layers are based, for example, on mica, on SiO ₂ or on Al ₂ O ₃ . Such interference layers are referred to as single or multi-layer according to the number of dielectric layers. Printing inks with pigments of such thin-film interference layers are marketed, for example, under the name ^Iriodin® (single-layer) or ^Colorcrypt® (multi-layer) by Merck KGaA. Printing inks with multilayer interference layer pigments are also marketed by SICPA under the name ^OVI® (OVI=optically variable ink). A special case are magnetically orientable OVI pigments, which are aligned in a preferred direction by means of a magnetic field during or after the printing of the substrate. A subset of interference layers or interference layer pigments are cholesteric or other liquid crystals that can also be used. These are available, for example, as liquid-crystalline silicone polymers or as pigments in so-called STEP® colors (STEP= ^Shimmery Twin Effect Protection).

The effect pigments that can be used according to the invention, which assume a different hue depending on the viewing angle, can also be based on the WO 2011/064162 A2 described effect pigment compositions based with color shift effect. The pigments have a longest dimension of edge length 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 is selected. The transition metal is preferably Ag. The aspect ratio (i.e. the ratio of the longest end-to-end dimension to the thickness) is preferably at least 1.5, more preferably in a range from 1.5 to 300. The ratio of binder to metal pigment is preferably below 10: 1, especially below 5:1. Depending on the choice of the aspect ratio of the pigment, its longest end-to-end dimension and the adjustment of the pigment/binder ratio, the color when viewed in transmission and the color when viewed in reflection of the print layer can be adjusted (e.g. blue in transmission and silver, gold, bronze, copper or violet in reflection; also violet, magenta, pink, green or brown in transmission and various colors in reflection depending on the choice of pigment/binder ratio). Colors with a gold/blue color change between reflection and transmission (in other words, between reflected light and transmitted light observation) are, for example, in Examples 1, 2 and 3 in Table 1 of WO 2011/064162 A2 called. Furthermore, example 4 shows a gold/violet color change color, example 5 a green-gold/magenta color change color, example 7 a violet/green color change color and example 8 a silver/opaque color change color.

1. a) das Bereitstellen eines Substrats;
2. b) den Schritt des Verprägens eines ersten Substratbereichs auf solche Weise, dass taktile Substratverprägungen erzeugt werden, und den Schritt des Verprägens eines zweiten Substratbereichs auf solche Weise, dass mikrooptische Strukturen erzeugt werden, wobei der Schritt des Verprägens des ersten Substratbereichs und der Schritt des Verprägens des zweiten Substratbereichs in einem Arbeitsgang durchgeführt werden.

Preferably, in the embossing step b2) according to the first aspect of the invention, additional tactile substrate embossings can be produced, for example by intaglio printing. In particular, both the tactile substrate embossings and the relief structures forming a micromirror arrangement or a diffractive structure can be produced in one operation. Analogously to this, a method for producing a value document substrate which does not fall within the scope of protection of the claims is described below, wherein the value-document substrate has both tactile substrate embossings and micro-optical structures, the method comprising:

1. a) providing a substrate;
2. b) the step of embossing a first substrate area in such a way that tactile substrate embossings are produced, and the step of embossing a second substrate area in such a way that micro-optical structures are produced, the step of embossing the first substrate area and the step of embossing of the second substrate area can be carried out in one operation.

According to a preferred embodiment, the micro-optical structures are based on a relief structure forming a micromirror arrangement and/or on a relief structure forming a diffractive structure.

• Variante 1): Es wird an der Stelle der späteren mikrooptischen Struktur (z.B. des späteren Hologramms) ein Prägelack auf das Substrat aufgebracht. Der Prägelack kann z.B. thermoplastisch und/oder UV-härtbar sein und weiterhin bereits pigmentiert sein. Vorzugsweise handelt es sich um 100%-Systeme, d.h. lösemittelfreie und nicht-wässrige Formulierungen. Ölbasierende Systeme sind insbesondere bei Papiersubstraten möglich. Bei Sicherheitselementen (insbesondere Sicherheitsfolien), die zur Aufbringung im Fensterbereich (insbesondere einer Öffnung bzw. Aussparung) eines Wertdokuments geeignet sind, sollte der Prägelack vorzugsweise transparent sein, der Prägelack muss aber nicht zwangsläufig farblos sein. Zum Aufbringen des Prägelacks (insbesondere vorab) ist prinzipiell jedes Druckverfahren geeignet. Eine Aushärtung erfolgt direkt im Zuge der Prägung, vorzugsweise durch das Substrat hindurch. Bei ausreichend hoher Viskosität, sowie bei einem thermoplastischen System, kann die Aushärtung auch unmittelbar nach dem Prägen erfolgen. Im Anschluss wird zumindest der mikrooptische Bereich mit einer effektpigmentieren Druckfarbe, bei welcher die Pigmente eine Spiegelreflexion bewirken und sich den holographischen Strukturen anpassen, überdruckt. Soweit geeignete Effektpigmente bereits dem Prägelack zugegeben wurden, muss der Lack im Nachgang nicht mehr überdruckt werden.
• Variante 2): Der Prägelack wird nicht vorab, sondern mithilfe der Stichtiefdruckplatte aufgebracht. Die Stichtiefdruckplatte trägt bereits die mikrooptischen Informationen und wird in diesen Bereichen mit dem Prägelack beaufschlagt. Bei dem Prägelack kann es sich neben einem UVhärtbaren System auch um ein ölbasierendes System handeln. Bei Sicherheitselementen (insbesondere Sicherheitsfolien), die zur Aufbringung im Fensterbereich (insbesondere einer Öffnung bzw. Aussparung) eines Wertdokuments geeignet sind, sollte der Prägelack transparent, aber nicht zwangsläufig farblos sein. Denkbar ist in diesem Fall auch eine effektpigmentierte Druckfarbe, bei welcher die Pigmente idealerweise eine Spiegelreflexion bewirken. Z.B. können dies Silber-, Kupfer, Nanopartikel oder dünne Aluminiumplättchen sein. Durch Leafing-Pigmente sowie Non-Leafing-Pigmente und die durch die Verprägung erzwungene Orientierung wird das mikrooptische Merkmal erzeugt. Die Aushärtung kann direkt im Zuge der Verprägung, vorzugsweise durch das Substrat hindurch oder bei ausreichend hoher Viskosität, sowie bei einem thermoplastischen System auch unmittelbar nach dem Prägen, erfolgen. Bedarfsweise wird im Anschluss zumindest der mikrooptische Bereich mit einer effektpigmentierten Druckfarbe, bei welcher die Pigmente eine Spiegelreflexion bewirken und sich den holographischen Strukturen anpassen, überdruckt.

There are two variants in particular for the production of a micro-optical structure, e.g.

• Variant 1): An embossing lacquer is applied to the substrate at the location of the later micro-optical structure (eg the later hologram). The embossing varnish can, for example, be thermoplastic and/or UV-curable and furthermore already pigmented. It is preferably 100% systems, ie solvent-free and non-aqueous formulations. Oil-based systems are particularly possible with paper substrates. In the case of security elements (in particular security foils) which are suitable for application in the window area (in particular an opening or recess) of a document of value, the embossing varnish should preferably be transparent, but the embossing varnish does not necessarily have to be colorless. To apply the embossing varnish (in particular beforehand), each suitable for printing processes. Curing takes place directly in the course of the embossing, preferably through the substrate. With a sufficiently high viscosity, as well as with a thermoplastic system, curing can also take place immediately after embossing. Subsequently, at least the micro-optical area is overprinted with an effect-pigmented printing ink, in which the pigments cause specular reflection and adapt to the holographic structures. If suitable effect pigments have already been added to the embossing varnish, the varnish does not have to be overprinted afterwards.
• Variant 2): The embossing varnish is not applied in advance, but with the help of the intaglio printing plate. The intaglio printing plate already carries the micro-optical information and the embossing varnish is applied to these areas. In addition to a UV-curable system, the embossing varnish can also be an oil-based system. In the case of security elements (in particular security films) which are suitable for application in the window area (in particular an opening or recess) of a document of value, the embossing varnish should be transparent but not necessarily colorless. In this case, an effect-pigmented printing ink is also conceivable, in which the pigments ideally bring about a specular reflection. For example, this can be silver, copper, nanoparticles or thin aluminum plates. The micro-optical feature is produced by leafing pigments and non-leafing pigments and the orientation forced by the embossing. The curing can take place directly in the course of the embossing, preferably through the substrate or if the viscosity is sufficiently high, and also immediately after the embossing in the case of a thermoplastic system. If necessary, at least the micro-optical area is then treated with an effect-pigmented printing ink, in which the pigments have a Cause specular reflection and conform to holographic structures, overprinted.

The intaglio printing plate can preferably carry other chromatic colors, i.e. provide color, with the areas that are intended to reproduce the holographic structures not providing color. However, an overlap is ideal due to the higher security against forgery due to the perfect register situation.

A register-accurate combination of steel embossing and hologram embossing can be ensured in this way in an advantageous manner. Furthermore, an increase in cost efficiency is possible because lower material costs arise and a more efficient manufacturing process is brought about. Fewer operations lead to less scrap and less set-up times. Furthermore, a very thin embossing lacquer layer thickness can be achieved since the substrate can be embossed at the same time. As a result, better mechanical resistances are achieved.

Preferred variant A:
A preferred steel printing cylinder according to a variant A comprises one or more areas with a micro-optical embossing and one or more areas for tactile substrate embossing (which are coloring and/or non-coloring). The area with a micro-optical embossing is particularly suitable for the production of lens structures, micro-mirror arrangements and/or holograms or hologram-like structures.

The substrate has an embossing varnish, e.g. a thermoplastic, which can be present partially or optionally over the entire surface.

The embossing varnish is a transparent, UV-curable system that is cured at the moment of embossing or immediately after embossing. In this case, exposure can take place through the substrate. The embossing varnish can already contain metal pigments or be overprinted with a metal-pigmented ink afterwards. A leafing UV-curable system should be particularly advantageous for a paint that has already been provided with metal pigments, since the leafing pigments float to the top and the embossing can thus be optimally molded into the pigments. Providing the substrate with a primer layer, possibly with a UV primer, is optional.

Preferred variant A with leafing ink:
A preferred steel printing cylinder according to variant A with leafing ink comprises one or more areas with a micro-optical embossing and one or more areas for tactile substrate embossing (which are inking and/or non-inking). The area with a micro-optical embossing is particularly suitable for the production of lens structures, micro-mirror arrangements and/or holograms or hologram-like structures.

The substrate has an embossing varnish, for example a thermoplastic, which can be present partially or optionally over the entire surface, and has leafing pigments.

A leafing UV-curable system should be particularly advantageous for a paint that has already been provided with metal pigments, since the leafing pigments float to the top and the embossing can thus be optimally molded into the flexible pigments. At the moment of embossing, the lacquer has not yet hardened. An exposure preferably takes place directly with the embossing through the substrate.

Preferred variant B:
A preferred steel printing cylinder according to a variant B comprises one or more areas with a micro-optical embossing and one or more areas for tactile substrate embossing (which are coloring and/or non-coloring). The area with a micro-optical embossing is particularly suitable for the production of lens structures, micro-mirror arrangements and/or holograms or hologram-like structures.

Not the substrate, but the areas with micro-optical embossing in the steel printing cylinder have an embossing varnish, e.g. a thermoplastic. If necessary, the embossing varnish can also be present in the areas formed in the steel printing cylinder for tactile substrate embossing.

The embossing varnish is a transparent, UV-curable system that is cured at the moment of embossing or immediately after embossing. The embossing varnish can also be oil-based or dual-cure. The embossing varnish can be processed by steel printing. In this case, exposure can take place through the substrate. The embossing varnish can already be provided with metal pigments or with one afterwards metal-pigmented ink can be overprinted. Providing the substrate with a primer layer, possibly with a UV primer, is optional.

Preferred variant "A + B":
A preferred steel printing cylinder according to a variant "A+B" comprises one or more areas with a micro-optical embossing and one or more areas for tactile substrate embossing (which are coloring and/or non-coloring). The area with a micro-optical embossing is particularly suitable for the production of lens structures, micro-mirror arrangements and/or holograms or hologram-like structures.

The substrate has an embossing varnish, e.g. a thermoplastic, which can be present partially or optionally over the entire surface. In addition, the areas in the steel printing cylinder with micro-optical embossing have an embossing varnish, e.g. a thermoplastic. If necessary, the embossing varnish can also be present in the areas formed in the steel printing cylinder for tactile substrate embossing.

In particular, the embossing varnish present on the substrate, e.g. a thermoplastic, can optionally be pre-gelled and optionally provided with effect-pigmented printing ink. In this way, the substrate is partially pre-impregnated in the area of the micro-optical structures and higher layer thicknesses can be realized.

The embossing varnish is a transparent, UV-curable system that is cured at the moment of embossing or immediately after embossing. In this case, an exposure can be carried out through the substrate take place. The embossing varnish can already contain metal pigments or be overprinted with a metal-pigmented ink afterwards. A leafing UV-curable system should be particularly advantageous for a paint that has already been provided with metal pigments, since the leafing pigments float to the top and the embossing can thus be optimally molded into the pigments. Providing the substrate with a primer layer, possibly with a UV primer, is optional.

Variant "A + B" corresponds to a two-layer embossing lacquer system. The first lacquer layer is optimized for the substrate, is applied to the substrate and may already have hardened or gelled at the moment of embossing. As a result, it is already perfectly anchored to the substrate and the substrate is partially pre-impregnated in the area of the fine holographic structures for the following layer of paint. The lacquer on the embossing tool, in particular the intaglio printing plate, can now be processed using the so-called casting process. It can no longer bounce away and anchors perfectly with the first coat. The variant "A + B" enables higher line speeds due to the higher optical quality (especially less bubble formation). Furthermore, deeper micro-optical structures can be realized.

Examples of suitable non-leafing pigments are PVD aluminum flakes whose surface is untreated or polar. With suitable leafing pigments, the polar or oxidized pigment surface is reversed with long-chain alkyl phosphonic acids or mono-/diphosphoric acid esters and long-chain alkoxysilanes, i.e. made non-polar (roughly comparable to the effect of surfactants, the polar part is anchored on the pigment surface either covalently or via acid -Base interaction). The pigments can optimally spread due to the platelet structure that is as perfect as possible orient (i.e. align the mirrors). For this purpose, leafing pigments are preferably as thin as possible, while non-leafing pigments are preferably to be chosen thicker. As a rule, the pigments have a D50 of 10 µm, the thickness is in the nanometer range.

In the case of variant B and variant "A+B", the micro-optical embossing can be overprinted after application with a solvent-based ink, preferably with non-leafing pigments.

In the case of variant B, preference is given to using non-leafing pigments if the embossing varnish itself is provided with platelet-shaped pigments (the pigments are based on the embossing tool). Since mobility in the embossing varnish is insufficient or hardly possible after application, it makes sense to use metal nanoparticles for direct pigmentation.

In the "A+B" variant, the embossing varnish that has already been applied to the substrate can be equipped with perfect non-leafing pigments or perfect leafing pigments. What is ultimately important here is a mirror that is as perfect as possible.

In this case, it is advantageous to use the embossing varnish portion on the embossing tool with a very highly pigmented embossing varnish (especially non-leafing), ie varnish with a very high pigment content, so that it is practically impossible to distinguish between non-leafing and leafing. In this case, this is possible since a further proportion of embossing varnish is contributed via the substrate for the embossing structures.

Particular exemplary embodiments and advantages of the invention are explained below with reference to the figures, which are not shown to scale and in proportion in order to improve clarity.

Figuren 1 bis 3

ein Beispiel für die Herstellung eines Wertdokumentsubstrats;

Figuren 4 bis 7

ein nicht unter den Schutzumfang der Ansprüche fallendes Beispiel für die Herstellung eines Sicherheitselements;

Figur 8

eine schematische Darstellung einer Banknote mit einem Sicherheitselement;

Figur 9

eine schematische Darstellung einer weiteren Banknote mit einem Sicherheitselement.

Show it:

Figures 1 to 3

an example for the production of a value document substrate;

Figures 4 to 7

an example of the production of a security element not falling under the scope of the claims;

figure 8

a schematic representation of a banknote with a security element;

figure 9

a schematic representation of another banknote with a security element.

The invention is first explained in more detail using examples of security elements for protecting banknotes, which do not fall under the scope of protection of the claims. figure 8 shows a schematic representation of a bank note 14 with a transparent window area 16 (shown in broken lines) which is provided with a security element 15 in the form of a patch or label.

The banknote 14 can, for example, be based on a (e.g. transparent) plastic substrate, with the banknote having no printing ink in area 16 either on the front or on the back, so that area 16 is recognizable to the viewer as a transparent window area.

The bank note 14 can alternatively be based on a foil/paper/foil composite substrate, with the central paper layer having a recess (in particular filled with transparent adhesive or filler) in the area 16 . Film / paper / film composite substrates are from WO 2004/028825 A2 known.

According to a further alternative, the banknote 14 is based on a paper/foil/paper composite substrate, with the outer paper layers each having a recess in the region 16 (see, for example, WO 2006/066431 A1 ).

According to a further alternative, the bank note 14 is based on a paper substrate which has a continuous recess in the area 16 . The continuous recess is covered by a transparent film on at least one side of the paper substrate (see, for example, WO 2011/015622 A1 ).

That in the figure 8 The security element 15 shown contains a central, color-shifting motif 17 formed by a micromirror arrangement, which is surrounded by a motif 16 formed by a hologram. figure 9 shows a schematic representation of another, on a

Paper substrate based banknote 18 which does not fall under the scope of the claims and which is provided on its front side with a security element in the form of a strip 19 (shown in phantom) is provided. In the present example, the strip 19 has a width of 8 mm and has a colour-shifting motif 21 formed by a micromirror arrangement and a motif 20 formed by a hologram.

The construction and production of a security element 19 are described below in connection with the Figures 4 to 7 explained in more detail. figure 7 shows that in the figure 9 illustrated security element 19 in a cross-sectional view along the dashed line AA'.

According to the figure 4 a carrier 6 in the form of a (eg transparent) plastic film, eg a PET film, is provided with an embossable lacquer 7 . The embossable lacquer 7 is, for example, a UV-curing lacquer or a thermoplastic lacquer.

According to the figure 5 the surface of the embossable lacquer 7 is provided by embossing in the partial area 8 with a relief structure formed by a microstructure and in the partial area 9 with a relief structure formed by a nanostructure.

According to the figure 6 is the embossing varnish 7 in the section 9 with the from WO 2005/051675 A2 known ink printed. The printing ink is based on platelet-shaped metal pigments (in particular Al pigments) and leads to the production of a reflection layer 11, in the present case a "silver" mirror layer.

In addition, the embossing lacquer 7 is printed in the partial area 8 with effect pigments, which assume a different shade depending on the viewing angle, in this example OVI ^® color. In this way, the layer 10 with the color shift effect is obtained by printing. According to the figure 7 the layer structure obtained is provided with a (eg transparent) intermediate layer or primer layer 12 (eg a UV lacquer) and a heat-sealing lacquer 13 suitable for gluing the security element to a value-document substrate.

In the Figures 4 to 7 describes the manufacture of a security element in the form of a strip (see reference number 19 in figure 9 ). The Indian figure 9 The security strip 19 shown has a color-shifting motif 21 formed by a micromirror arrangement and a motif 20 formed by a hologram. The motif 21 formed by a micromirror arrangement corresponds to that in FIG figure 6 area indicated by reference numeral 10. The motif 20 formed by a hologram corresponds to that in FIG figure 6 area indicated by reference numeral 11.

That in the figure 7 The security element shown may alternatively be in the form of a patch or label (see, for example, the patch denoted by reference number 15 in figure 8 ).

In the in the Figures 4 to 7 In the example shown, which does not fall under the scope of the claims, the embossing step takes place first (see figure 5 ), after which the embossed areas are printed with pigments (see figure 6 ). According to an alternative example not shown in the figures, the step of printing with pigments takes place first and then the step of embossing.

Figures 1 to 3 describe an example for the production of a value document substrate, in the present case a security paper suitable for the production of banknotes and not falling under the scope of protection of the claims.

According to the figure 1 In a first step, a paper substrate 1 is provided.

According to the figure 2 the surface of the paper substrate 1 is provided by means of blind embossing using an intaglio printing device in partial area 2 with a relief structure formed by a microstructure and in partial area 3 with a relief structure formed by a nanostructure.

According to the figure 3 is the embossed paper substrate 1 in portion 3 with the from WO 2005/051675 A2 known ink printed. The printing ink is based on platelet-shaped metal pigments (in particular Al pigments) and leads to the production of a reflection layer 5, in the present case a "silver" mirror layer.

In addition, the embossed paper substrate 1 is printed in the partial area 2 with effect pigments, which assume a different shade depending on the viewing angle, in the present example ^OVI® color. In this way, layer 4 with a color shift effect is obtained by printing.

In the in the Figures 1 to 3 In the example shown, the first step is to emboss the paper substrate (see figure 2 ), after which the embossed areas of the paper substrate are printed with pigments (see figure 3 ). According to an alternative example not shown in the figures first the step of printing the paper substrate with pigments and then the step of embossing the paper substrate.

Claims (4)

1. A method for manufacturing a value document substrate suitable for a bank note (14,18), namely a polymer bank note or foil composite bank note, comprising

   a) the supplying of a substrate (1), namely a plastic substrate or a foil/paper/foil composite substrate;

   b1) the printing of the substrate (1) with platelet-shaped metal pigments suitable for the forming of a reflective layer (4, 5) in a first substrate region, and the printing of the substrate with effect pigments, which adopt a different hue depending on the viewing angle, in a second substrate region;

   b2) the step of embossing the first substrate region and the second substrate region such that (i) the substrate (1) in the first substrate region has a relief structure which forms a diffractive structure, and the substrate (1) in the second substrate region has a relief structure which forms a micro-mirror arrangement, or (ii) the substrate (1) in the first substrate region has a relief structure which forms a micro-mirror arrangement, and the substrate (1) in the second substrate region has a relief structure which forms a diffractive structure.
2. The method according to claim 1, wherein step b1) is carried out before step b2), wherein in step b2) both the platelet-shaped metal pigments suitable for the forming of a reflective layer (4, 5) in the first substrate region and the effect pigments in the second substrate region, which adopt a different hue depending on the viewing angle, adapt to the relief structure of the substrate (1) in the respective substrate region.
3. The method according to claim 1, wherein step b2) is carried out before step b1), wherein in step b1) both the platelet-shaped metal pigments suitable for the forming of a reflection layer (4, 5) in the first substrate region and the effect pigments in the second substrate region, which adopt a different hue depending on the viewing angle, adapt to the relief structure of the substrate (1) in the respective substrate region.
4. The method according to any of claims 1 to 3, wherein the step of embossing b2) is carried out by means of blind embossing, preferably by means of an intaglio-printing device.

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