WO2013079206A1

WO2013079206A1 - Security paper and value document that can be obtained therefrom

Info

Publication number: WO2013079206A1
Application number: PCT/EP2012/004937
Authority: WO
Inventors: Jürgen ZERBES
Original assignee: Giesecke & Devrient Gmbh
Priority date: 2011-12-02
Filing date: 2012-11-29
Publication date: 2013-06-06
Also published as: DE102011120063A1; EP2785533A1

Abstract

The invention relates to a security paper for producing value documents, such as banknotes, passports, identity documents or the like, having a flat substrate which is equipped on at least one surface with at least one anti-forgery means, wherein the anti-forgery means is based on a carrier film having mutually opposite first and second main surfaces and the first main surface of the carrier film, which can be perceived by the observer at least in some regions, and is located opposite the substrate, has an optically variable security feature which forms a first pattern that can be perceived when viewed in incident light, and the anti-forgery means and a partial area of the substrate surrounding the anti-forgery means is provided with a partial, non-covering, optically variable lacquer over-coating made of spaced, printed structural elements, which form a second pattern that can be perceived when viewed in incident light. The anti-forgery means can be based on micro lens systems or micro mirror arrays for the enlarged depiction of microstructures. The optically variable lacquer over-coating can be based on effect pigments, for example pearlescent pigments or liquid crystalline pigments. The substrate can be provided with a dirt-repelling lacquer on the surface thereof located outside the lacquer over-coating.

Description

Security paper and value document available therefrom

The invention relates to a security paper for the production of value documents, such as banknotes, passports, identity documents or the like, having a flat substrate which is equipped on a surface with an optically variable security feature having anti-counterfeiting means. The invention further relates to a document of value with such a security paper.

Security documents such as banknotes, stocks, bonds, certificates, vouchers, checks, high-quality admission tickets, as well as other papers that are prone to forgery, such as passports or other identification documents, are often provided with counterfeit securities for verification, which allow verification of the authenticity of the value document which also serve as protection against unauthorized reproduction. The tamper-evident means may for example be in the form of a security thread completely or partially embedded in a banknote or in the form of a security strip or patch applied to the banknote.

In recent years, counterfeit security devices, in particular security threads, have established themselves with optically variable security features on the banknote market. Optically variable security features give the viewer a different image impression under different viewing angles. The security features can be present in particular in the form of diffraction-optically active microstructures or nanostructures, such as in the case of conventional embossed holograms or other hologram-like diffraction structures (see, for example, the publications EP 0 330 733 A1 or EP 0 064 067 A1). It is also known to use lens systems as security features. Thus, for example, EP 0 238 043 A2 and DE 36 09 090 A1 describe a security thread made of a transparent material, on the surface of which a grid of several parallel cylindrical lenses is embossed. The thickness of the security thread is chosen so that it corresponds approximately to the focal length of the cylindrical lenses. On the opposite surface of a printed image is applied register accurate, the print image is designed taking into account the optical properties of the cylindrical lenses.

For some time, so-called Moire magnification arrangements are used as security features. Such a moire magnification arrangement is disclosed in the document WO 2006/087138 AI or in DE 10 2005 028 162 AI. The counterfeit protection device disclosed in WO 2006/087138 A1 has at least one first and one second security feature. In this case, the first authenticity feature comprises a first arrangement having a multiplicity of focusing elements which are present in a first grid, and a second arrangement having a multiplicity of microscopic structures which are present in a second grid. The first and second arrays are arranged one another such that the microscopic structures of the second array are magnified as viewed through the focussing elements of the first array. Such a magnification effect is also referred to as Moire magnification. In short, moiré magnification thereafter refers to a phenomenon that occurs when viewing a raster of identical image objects through a lenticular of approximately the same pitch. As with any pair of similar rasters, this results in a moire pattern, in which case each of the moire fringes is in shape an enlarged and rotated image of the repeated elements of the image grid appears.

It is also known to use optically variable security features based on periodic or aperiodic sawtooth gratings (see, for example, WO

2011/066991 A2) or based on micro-cavity mirror arrays (see, for example, DE 10 2009 035 361 A1).

To extend the service life and fitness for circulation, securities can be provided with a dirt-repellent protective layer. For example, EP 0 256 170 B2 proposes to provide printed bills with a protective layer which contains cellulose ester or cellulose ether to a greater extent and, to a lesser extent, micro-sized wax, and which is applied over the entire surface to the bills. The micronized wax is thereby dispersed by kneading or mixing with oil, a paint remover or a mixture thereof. The sheets freshly printed with the protective layer can be easily stacked without discoloring black color from a sheet to the underlying sheet.

Optically variable counterfeit protection means, in particular security elements with a microoptical representation arrangement with microstructures and microimage elements for enlarged imaging of the microstructures, for example microlens systems or micro hollow mirror arrays, can not be provided with a dirt-repellent protective layer as a result of a possible impairment of the optical effect. The partial application of a dirt-repellent protective layer to a banknote equipped with an optically variable counterfeit security device such that the protective layer in the area of the anti-counterfeiting device Tels has a recess, leading to disturbing dirt spots in the area of the recess.

Based on this, the object of the invention is to avoid the disadvantages of the prior art and, in particular, to provide a security paper with an optically variable counterfeit protection device, which reveals, in circulation, an improved optical quality of the counterfeiting device with regard to disturbing dirt stains. This object is achieved by the feature combinations defined in the independent claims. Further developments of the invention are the subject of the dependent claims.

Summary of the invention

A first aspect of the invention relates to a security paper for producing value documents, such as banknotes, passports, identity documents or the like, having a planar substrate which is provided on at least one surface with at least one counterfeit protection means, wherein the counterfeiting means on a carrier film with opposing first and is based on the second main surfaces and for the viewer at least partially perceptible, the substrate opposite the first main surface of the carrier film has an optically variable security feature that forms a perceptible in the incident light first motif, and

the anti-counterfeiting means and a partial surface of the substrate surrounding the anti-counterfeiting agent with a partial, non-opaque, optically variable overpainting of spaced, printed Structural elements is provided which forms a perceptible when viewed in incident light second motif.

The term overcoating used herein is to be understood as a printable coating, in particular a coating obtainable by means of screen printing or flexographic printing.

The optically variable security feature of the counterfeit security device can be based, in particular, on microimage elements, for example microlens systems or micromobular mirror arrays, for enlarged imaging of microstructures. Furthermore, it is preferred that the partial, non-opaque, optically variable overpainting has a color-shift effect (or color flop) and / or brightness-shift effect (or brightness flop). It is preferred that the partial, non-opaque, optically variable overcoating is based on effect pigments which are chosen in particular from pearlescent pigments or pigments prepared on the basis of liquid-crystalline polymers. The spaced, printed structural elements of the partial, non-opaque, optically variable overcoat preferably have a percent area coverage of at most 70%, more preferably up to a maximum of 50%. The term "percentage area coverage" refers to the ratio of the area formed solely by the spaced, printed structural elements, based on the total area occupied by the spaced printed structural features and the intervening white areas and non-printed areas, respectively is formed. The offending, printed structural elements of the partial, non-opaque, optically variable overpainting can in particular form a dot matrix, line grid or a grid of image objects or alphanumeric characters.

It is preferred that the first motif formed by the optically variable security feature of the anti-counterfeiting means has identical, repeating first picture elements and the second motif formed by the partial, non-opaque, optically variable overpainting has identical, repeating second picture elements. In particular, it is preferred that the shape or appearance of the first picture elements match the shape or appearance of the second picture elements.

The anti-counterfeiting agent can be present in particular as a security strip, patch, or security thread, preferably as a window security thread.

It is preferred that the substrate is provided with a dirt-repellent lacquer, at least on its surface lying outside of the partial, non-opaque, optically variable overpainting.

In particular, the soil-repellent varnish may be based on (a) a physically drying, water-based dispersion varnish which cures by removal of the dispersing agent or (b) is based on a UV-crosslinking varnish.

It is particularly preferred that the soil-repellent paint is based on a physically drying, water-based dispersion paint, which is cured by removing the dispersing agent and is an aqueous dispersion of a polyacrylic resin or a polyurethane resin.

Furthermore, it is preferred that the substrate is printed with characters or patterns, and the optionally existing soil-repellent paint is applied to the printed substrate and / or the optionally present dirt-repellent paint is printed.

A second aspect of the invention relates to a value document, such as a banknote, a passport, a passport document or the like, the security document having a security paper according to the first aspect of the invention.

Detailed description of the invention

The invention is based on the finding that contaminants in the region of an optically variable counterfeit protection means can be concealed or obscured by the application of a partial, non-opaque, optically variable overpainting. Overpainting, to some extent, has the function of a camouflage painting, which ensures that, for example, dirt stains arising in banknote circulation are no longer perceived as such in the area of the counterfeiting agent. At the same time, the visibility of the optical effect of the anti-counterfeiting agent is not particularly impaired by the overpainting, because the overpainting is not present over the entire surface but partially in the form of spaced, printed structural elements. In this way, the optically variable security feature of the anti-counterfeiting means, which is arranged below the partial overpainting, can be perceived at least in regions for the viewer. It is appropriate, the Structural elements with respect to their dimensions in such a way that adjacent structural elements are distinguishable to the naked eye. It has been found that the spaced, printed structural elements of the partial, non-opaque, optically variable overcoat should preferably have a percentage area coverage of at most 70%, more preferably up to a maximum of 50%. In this way, the prone to contamination area of the anti-counterfeiting agent can be particularly well protected against contamination, without the perceptibility of the optically variable security feature of the anti-counterfeiting means is all too much affected.

The spaced, printed structural elements of the partial, non-opaque, optically variable overpainting can in particular form a dot matrix, line grid or a grid of image objects or alphanumeric characters. In the case of a line grid, it may be e.g. to act a bunch of parallel lines or a cross grid.

It has been shown that coatings suitable for overcoating, in particular for effect pigments, are suitable. Non-opaque, optically variable paints based on effect pigments are known in the art (see, for example, EP 1 391 318 B1). In particular, pearlescent pigments, metallic effect pigments, multilayered pigments with transparent or transparent and opaque layers, holographic pigments, BIOC1 and LCP pigments (LCP = Liquid Crystal Polymer) are understood as meaning effect pigments.

It is particularly preferred overpainting based on effect pigments, wherein the effect pigments of pearlescent pigments or of LCP pigments are selected. Pearlescent pigments are commercially available, for example, under the trademark Iriodin® Fa. Merck. Pigments based on liquid-crystalline polymers are known in the art (see, for example, WO 2008/000755 Al). It has been shown that by means of a partial, non-opaque, optically variable overpainting based on pearlescent pigments or LCP pigments, it is not only possible to mask soiling but also to create aesthetically attractive motifs. The motif of the optically variable security feature of the anti-counterfeiting agent is superimposed on the motif which is produced by the special effect pigment overpainting. The observer, who fixes the relevant area of the security thread with the eye and tilts the security paper in a subsequent step while verifying the counterfeit security device, eg a (window) security thread with a microlens or micro-concave security feature, takes particular advantage of the dynamic movement effect of the security feature impressively true, because this addition of the by the

Overpainting generated color shift effect (or color flop) and / or brightness shift effect (or brightness flop) is superimposed.

The superimposition of the two optical effects described above can be increased with respect to the effectiveness on the viewer by having the first motif formed by the optically variable security feature of the anti-counterfeiting means identical, repeating first picture elements and that by the partial, non-opaque, optically variable Overpainting formed second motif identical, repeating second picture elements and the shape or the appearance of the first picture elements with the shape or the appearance of the second picture elements match. Alternatively, the superposition of the two optical effects can be increased in an associative sense, if the repeating first picture elements, although different picture elements than the derholenden second pixels are, but with each other in a meaningful relationship (eg, a microlens thread having as the optically variable motif first picture elements in the form of a sun and a top coat, which has as the optically variable motif second picture elements in the form of a moon).

The overcoat can in particular contain one or more effect pigments. By using at least two different effect pigments special color and gloss effects can be achieved. Furthermore, blends of one or more effect pigments with organic and / or inorganic pigments are possible. By mixing, the color shift effects (or color flops) and / or brightness shift effects (or brightness flops) can be adjusted in a targeted manner. The partial, non opaque, optically variable overcoating can in the

Flexographic printing process or be applied in offset printing. The application can be made in the paper mill or in the printing house.

The anti-fouling agent based on a carrier film can be in the form of a security strip, a security thread or in the form of a label or patch, for example. The optically variable security feature provided with the anti-counterfeiting agent can be in the form of diffractive optical microstructures or nanostructures, for example in the case of conventional embossed holograms or other hologram-like diffraction structures (see, for example, EP 0 330 733 A1 or EP 0 064 067 AI). The security feature can be based, in particular, on lens systems (see, for example, the publications EP 0 238 043 A2 and DE 36 09 090 A1) or on hollow micromirror arrays (see, for example, DE 10 2009 035 361 A1). The forgery-proofing means can be visually recognizable to the observer completely or only partially. An example of an only partially visually recognizable counterfeit protection means is a window security thread (eg a microlens thread), which emerges in window areas on the surface of a banknote, while it is embedded in the intervening web areas inside the banknote (see, for example, FIGS. 1 of WO 2004/097112 AI). For application-technical reasons, the partial, non-opaque, optically variable overpainting is not applied register-accurate above the anti-counterfeiting agent, but the varnish also covers part of the security paper substrate which surrounds the anti-counterfeiting agent and forms, as it were, an edge region for the anti-counterfeiting means (the The "anti-counterfeiting agent surrounding part surface" used herein is representative of the edge region.) The anti-counterfeiting agent may be circumferentially surrounded by the overcoating, such as in the case of a patch-shaped anti-counterfeiting agent , which extends from one edge of the banknote to the opposite edge, the anti-counterfeiting agent is surrounded on two sides by the overpainting, ie the counterfeiting means and two elongated counterparts to the counterfeiting means Part surfaces of the substrate are provided with the overcoat.

The partial area of the substrate surrounding the anti-counterfeiting means, ie the edge area, can in particular have a width of 1 to 25 mm, preferably 2 to 7 mm, measured from the outer edge of the counterfeit security device. To the outer edge of the adjacent part surface of the substrate, have.

With regard to the extension of the service life and the ability to circulate the security paper, it is particularly advantageous to provide the security paper substrate with a conventional dirt-repellent lacquer on its surface lying outside the counterfeit security device, which has the partial, non-opaque, optically variable overcoat in the area If necessary, the partial area of the substrate surrounding the anti-counterfeiting device may partially overlap. The dirt-repellent lacquer may in particular be based on a physically drying, water-based dispersion lacquer which hardens by removal of the dispersion medium (see, for example, the publications WO 00/00697, EP 0 815 321 B1 and EP 1 338 430 A1), or on a UV crosslinking paint containing optionally matting agents.

Suitable UV-crosslinking lacquer layers with high physical and chemical resistance are known in the prior art (see, for example, EP 1 595 029 B1). The UV-crosslinking, soil-repelling lacquer may in particular be a monomeric acrylate (mono-, di-, tri- and / or tetrameric acrylate) and optionally additives or processing aids, such as defoamers, dispersants, UV curing accelerators , Viscosity modifiers, leveling agents and stabilizers. The UV varnish may further consist of an acrylate mixture, preference being given to an acrylate mixture obtained by reacting at least one prepolymeric acrylate of average molecular weight of, for example, 500 to 2000 with the monomeric acrylate (mono-, di-, tri- and / or tetrameric acrylate), wherein the lacquer comprises 100 parts by weight of the acrylate lacquer (calculated without additive or processing aid) and 1 to Contains 10 parts by weight of a UV initiator or UV initiator mixture or consists of these components. For UV curing, for example, UV rays in a range of 100 to 450 nm, preferably 100 to 200 nm, particularly preferably from 130 to 190 nm are suitable. The soil-repellent UV lacquer can in particular be based on mixtures of mono- and / or difunctional monomeric acrylates, prepolymeric acrylates, and tri- and / or tetrafunctional monomeric acrylates. As prepolymeric acrylates, for example, polyester acrylates, urethane acrylates, acrylic acrylates and / or methacrylacrylates, oligoester acrylates, epoxy acrylates, and / or mixtures of two or more of these prepolymeric acrylates can be used. It is preferred that the soil-repellent UV varnish has silicones and / or waxes to improve its soil-repelling properties. In addition to radically crosslinking UV lacquers, cationic crosslinking lacquer systems are also suitable. The soil-repelling UV varnish may be present on the substrate in particular at a coating weight of 0.5 to 3 g / m ² , preferably 1 to 2 g / m ² . This corresponds, with respect to the preferred range in the uncrosslinked state, to an amount of about 1 to 2 g / m ² because UV systems are so-called "100% systems" (ie 100% solids).

An example of a dirt-repellent UV varnish is listed below:

Composition 1:

UV lacquers "UV L50733" and "UV L50734" from Pröll in a mixing ratio of 3: 2. These are applied dry with a 9 cc / m roll in an application amount of about 1.8 g / m ² . In particular, physically drying aqueous dispersions based on a polyacrylic resin and / or a polyurethane resin are preferred for forming the soil-repelling paint. The paint can in particular be based on a one-component polyurethane system or one-component polyacrylate system with pre-crosslinked polyurethane or polyacrylate. But it can also be used blocked polyurethane having chemically bonded to the polymer chains isocyanate groups. The isocyanate groups can be regenerated at elevated temperatures, which are generally used in the security printing process. Furthermore, two-component polyurethane systems or

Polyacrylate systems which are crosslinkable by using multifunctional reagents, such as melamine / formaldehyde precondensates. In general, the polyurethane may in particular be of the aliphatic polyester type and / or of the aliphatic polyether type. It is also possible to use aliphatic polycarbonate polyurethane. The polyacrylate may generally be e.g. of the aromatic type, such as a styrene / acrylic copolymer. Mixtures of a polyurethane and a polyacrylate may e.g. in a weight ratio of 90:10 to 10:90, preferably 75:25 to 25:75 are used. The physically drying aqueous dispersions may contain additional ingredients such as catalysts, co-solvents, dispersing aids, defoamers, viscosity modifiers, extenders, fluorescent and / or iridescent additives and / or surfactants. A typical physically drying aqueous dispersion has e.g. a polyurethane of the aliphatic polyester or aliphatic polyether type having a polyurethane content of from 2 to 70% by weight, preferably from 5 to 30% by weight.

The soil-repellent coating based on an aqueous dispersion may preferably be applied to the security paper by means of the flexographic printing process be applied. The lacquer layer is expediently applied in a coating amount of 1 to 8 g / m ² . Examples of physically drying compositions of the soil-repellent paint are listed below:

Composition 2:

900 ml of aqueous dispersion of an acrylate ("Neocryl-AC 72" from Zeneca) 80 ml of water

20 ml crosslinker "CX 100" from Zeneca

Composition 3:

900 ml of aqueous dispersion of an acrylate ("Primal 1-545" Fa.

Rohm & Haas)

80 ml of water

20 ml zirconium carbonate Fa. Auer-Remy

Composition 4:

700 ml aqueous dispersion of an acrylate-styrene copolymer ("Glascol LS 26" from CIBA)

200 ml aqueous dispersion of a polyurethane ("U 400 N" from Alberdink Boley)

100 ml of water

20 ml crosslinker "CX 100" from Zeneca According to a preferred embodiment, the security paper is printed on the surface of the substrate lying outside the counterfeiting agent with signs or patterns in the course of producing a value document. As the dirt-repellent paint a print image above the dirt-repellent paint are printed.

With respect to the security paper substrate, there are no special restrictions. Banknote papers are typically made from fibers of annual plants, especially cotton fibers or pulp fibers, but papers which are at least partially made of plastic fibers, preferably polyamide fibers or polyester fibers, may also be used. Particularly preferably, a cotton paper is used as a security paper substrate. The basis weight of the substrate varies depending on the application form. Typical basis weights are in the range of 50 g / m ² to 100 g / m ² , preferably in the range of 60 g / m ² to 90 g / m ² , more preferably about 70 g / m ² . For multi-layer substrates, the individual paper layers may consist of the same or different types of paper. For example, a paper layer may be a pure one

Cotton paper, while another paper layer comprises plastic fibers. Furthermore, as the security paper substrate it is also possible to use multilayer paper / film composites, such as a paper / film / paper composite or a film / paper / film composite.

Also, there are no particular restrictions on the manner of manufacturing the security paper substrate. The production preferably takes place by means of a rotary screening machine. Further exemplary embodiments and advantages of the invention are explained below with reference to the figures, in the representation of which a representation in terms of scale and proportions has been dispensed with in order to increase the clarity. a schematic representation of a security paper with embedded window security thread and glued patchy security element; the enlarged portion II in plan view, wherein the sweeping zone of the thread is schematically illustrated; the enlarged area II in plan view, wherein the expansion of the partial, non-opaque, optically variable overpainting is schematically illustrated; and a schematic representation of the perceptible in the window areas of the thread first motif and formed by the Überla ckierung second motif.

Fig. 1 shows a schematic representation of a security paper 1, which is provided with an embedded window security thread 2 and a glued patch-shaped security element 3. The security paper 1 also has the denomination "100" in the form of a watermark, the window security thread 2 (in the present case a microlens thread) and the security element 3 (in the present case, a micro-optical representation arrangement with microstructures and micro-cavity mirror arrays for enlarged imaging of the microstructures ) give the viewer a different image impression in each case from different viewing angles The windowed security thread 2 shown by dashed lines appears on the window areas 4 on the surface of the security paper 1, while it is embedded in the intervening web areas inside the security paper 1.

The patch-shaped security element 3 and the window security thread 2 are each provided with a partial, non-opaque, optically variable overlap. In the present example, the overcoat is based on Iriodin® pearlescent pigments and was applied to the security paper in areas 5 and II by flexographic printing. The overpainting is not applied in register over the counterfeit protection means 2 and 3, but the overpainting also covers adjacent parts of the security paper substrate, which surround the counterfeiting protection means 2 and 3 and, so to speak, form edge regions for the counterfeit protection means 2 and 3. The security paper 1 is provided on its surface lying outside of the counterfeiting protection means 2 and 3 over the entire surface with a dirt-repellent second lacquer which partially overlaps the partial, non-opaque, optically variable overpainting in the region of the partial surfaces of the substrate surrounding the anti-counterfeiting means 2 and 3. In the present example, the dirt-repellent second paint is based on a physically-drying aqueous dispersion paint applied by means of flexographic printing.

Fig. 2a shows the enlarged section II of Fig. 1 in plan view. The window security thread 2 protrudes at the window areas 4 on the surface of the security paper while being embedded at the intermediate land areas inside the security paper. Thus, in stacked securities at the points of the security thread unwanted thickening (and thus a poor flatness of the paper sheets) can be avoided, the introduction of the security thread into the paper during papermaking by means of the known in the art Wöbbel technology. The term "wobble" here denotes a periodic variation of the security thread when embedding in the paper of several millimeters perpendicular to the thread direction, so that certain Wöbbel zones 6 are formed, within which the security thread comes to rest.

The window security thread 2 and a partial area of the substrate surrounding the window security thread 2 are provided with the above-described partial, non-opaque, optically variable overpainting 7 (see FIG. 2b).

FIG. 3 shows an example of the first motif perceivable in the window regions 41 of the thread and the second motif formed by the overcoat 71. When the security paper is tilted about the tilting axis formed by the window security thread, the moiré image "<<""formed by the microlens system moves longitudinally along the security thread (so-called" shadow ") orthoparallactic motion effect). The partial, non-opaque, optically variable overcoat 71 is in the form of a diagonal grid. 3, the line width of the raster lines can also be selected to be wider and have, for example, the same line width of the picture element "<" of the first motif Although slightly affected, the exposed micro-optic elements of the microlens thread are still susceptible to contamination glittering, optically variable overcoating 71 but effectively veiled.

Claims

Patent claims

1. Security paper for the production of documents of value, such as banknotes, passports, identity documents or the like, having a flat substrate which is provided on at least one surface with at least one counterfeiting security means, wherein

the anti-counterfeiting means is based on a carrier film with opposing first and second main surfaces and the observer at least partially perceptible, the substrate opposite the first main surface of the carrier film has an optically variable security feature that forms a perceptible in reflected light first motif, and

the anti-counterfeiting device and a partial surface of the substrate surrounding the counterfeiting device are provided with a partial, non-opaque, optically variable overpainting of spaced-apart, printed structural elements, which forms a second motif perceptible in incident light.

2. The security paper as claimed in claim 1, wherein the optically variable security feature of the counterfeiting protection means is based on microimage elements, in particular microlens systems or microsphere mirror arrays, for enlarged imaging of microstructures and the partial non-opaque, optically variable overcoating has a color shift effect.

3. Security paper according to claim 1 or 2, wherein the partial, non-opaque, optically variable overcoating based on effect pigments, the in particular of pearlescent pigments or pigments prepared on the basis of liquid-crystalline polymers are selected.

4. Security paper according to one of claims 1 to 3, wherein the spaced, printed structural elements of the partial, non-opaque, optically variable overpainting have a percent area coverage to at most 70%, preferably to at most 50%.

5. Security paper according to one of claims 1 to 4, wherein the spaced, printed structural elements of the partial, non opaque, optically variable overpainting form a dot matrix, line grid or a grid of image objects or alphanumeric characters.

6. The security paper according to claim 1, wherein the first motif formed by the optically variable security feature of the counterfeit security device has identical, repeating first image elements and the second motif formed by the partial, non-opaque, optically variable overpainting is identical, repeating second Having picture elements as spaced, printed structural elements.

7. Security paper according to claim 6, wherein the shape of the first

Picture elements matches the shape of the second picture elements.

8. Security paper according to one of claims 1 to 7, wherein the anti-counterfeiting agent as a security strip, patch, or security thread, in particular as a window security thread, is present.

9. Security paper according to one of claims 1 to 8, wherein the substrate at least on its outside of the partial, not opaque, optical variable overcoating lying surface is provided with a dirt-repellent paint.

The security paper of claim 9, wherein the soil-repellent varnish (a) is based on a physically drying, water-based dispersion varnish that cures by removal of the dispersant, or (b) is based on a UV-crosslinking varnish.

11. The security paper of claim 10, wherein the soil-repellent paint is based on a physically drying, water-based dispersion paint which cures by removal of the dispersant and is an aqueous dispersion of a polyacrylic resin or a polyurethane resin.

12. Security paper according to one of claims 1 to 11, wherein the substrate is printed with characters or patterns, and the optionally present dirt-repellent paint is applied to the printed substrate and / or the optionally present dirt-repellent paint is printed.

13. A value document, such as a banknote, a passport, a passport document or the like, the security document having a security paper according to one of claims 1 to 12.