EP1609619B1 - Security element with inserted patterns - Google Patents

Description

The invention relates to a security element for security papers, documents of value and the like, are incorporated in the motifs in the form of patterns, characters or codes. The invention also relates to a security paper, a value document and a method for producing such a security element.

Security documents are often provided with security elements for the purpose of security, which allow verification of the authenticity of the value document and at the same time serve as protection against unauthorized reproduction. Value documents within the meaning of the present invention are, in particular, bank notes, shares, bonds, certificates, vouchers, checks, high-quality admission tickets, but also other papers which are subject to counterfeiting, such as passports and other identity documents, as well as product security elements such as labels, seals, packaging and the like. The term "value document" in the following includes all such documents and product assurance means. By contrast, "security paper" is understood as the precursor to the value document, which is not yet ready for use.

To increase security and as counterfeit protection, the security elements are often provided with a so-called negative writing. This negative writing is formed by metal-free regions in an otherwise continuous metallic coating of the carrier material of the security element.

For the preparation of such metal-free areas is in the document WO 99/13157 describes a washing method in which a translucent carrier sheet is printed with a desired pattern using a high pigment ink. Due to the high pigment content Forms the ink after drying a porous, raised color. On the printed carrier film, a thin cover layer is then formed, which only partly covers the color body in the area of the paint application because of its large surface and the porous structure. The application of paint and the overlying covering layer can then be removed by washing with a suitable solvent, so that recesses are produced in the covering layer in the originally printed regions of the carrier film. By the achievable sharp contours can be introduced by printing a logo, for example, a legible negative writing in the cover layer.

document WO 03/068525 A1 discloses a security element according to the preamble of claim 1.

Proceeding from this, the present invention seeks to propose a security element of the type mentioned, which has a high security against counterfeiting and at the same time is easy to manufacture.

This object is achieved by the security element having the features of the main claim. A method for its production, a security paper and a value document with such a security element are specified in the independent claims. Further developments of the invention are the subject of the dependent claims.

According to the invention, when the security element is viewed, the introduced motifs are recognizable from opposite sides with different visual appearance. The motifs are recognizable as recesses in an opaque cover layer viewed from a first side, and appear from the second, opposite side through a substantially transparent or translucent optically variable effect layer with an optically variable effect.

Such a security element can be introduced, for example, as a window security thread in the paper of a banknote. The optically variable effect of the security thread then appears in partial areas on the surface of the paper, while the opaque, in particular metallic cover layer reduces the visibility of the thread on the back of the paper.

The introduced motifs, such as a lettering or a number sequence, appear congruent from both sides of the banknote, but with different optical impression, so that the effect is easy to recognize and check, but difficult to imitate.

According to the invention, the opaque cover layer comprises two color layers arranged one above the other, of which a first color layer is soluble in a liquid and the second color layer is insoluble in the liquid. In particular, the first color layer may be water-soluble and the second color layer may be waterproof. However, other liquids can be used within the scope of the invention. All that is essential is that the two printing inks are arranged on top of one another so that the liquid for the first color layer is a solvent, but the second color layer is insoluble in the liquid.

Preferably, the first color layer has a high pigment content, so that it forms a porous structure with a high surface area after drying. The pigment content is suitably between 10% and 80%, preferably about 60%, in each case based on the dry weight of the paint. For example, natural raw materials such as chalk, bentonite, aerosil or titanium dioxide can be used as pigments.

The first color layer is typically formed by a uniform ink. However, it can also be provided that the first color layer has partial areas with different color impressions in order to create areas of different colors on the security element.

The second color layer is preferably formed on nitrocellulose, polyamide or PVC base or based on a UV-curable lacquer.

In addition, the second color layer may also contain machine-readable feature substances, in particular luminescent, magnetic and / or electrically conductive feature substances, so that in addition an invisible, only machine-detectable coding can be incorporated into the security element. The second color layer may also be uniform, or have partial areas with different color impressions and / or partial areas with different machine-readable feature substances.

In some embodiments, it is expedient if the first and / or second color layer have a dark hue, such as black. However, other shades of the two color layers are within the scope of the invention. For example, in the first color layer usually no high order quantity is required, so that it can be applied over the entire surface in a lighter, not opaque color.

According to the invention, the first and second ink layers advantageously have congruent recesses which form at least part of the motifs introduced into the security element. Another part of the motifs may be formed by additional printed layers or optical effect layers, wherein the two motif parts may be independent of each other, but also work together and can complement each other, for example, to a total motive.

In an advantageous embodiment of the security element according to the invention, the opaque cover layer comprises a metal layer. The metal layer may in particular consist of aluminum, but also of another metal, such as copper, gold, iron, chromium, nickel, silver, platinum, palladium, titanium, another non-ferrous metal, or an alloy of these metals. The metal layer is preferably applied by the vacuum vapor deposition method.

In a preferred variant of the invention, the metal layer is arranged over the two color layers and has with these congruent recesses, which form at least a part of the introduced into the security element motifs. The security element then shows, viewed from the side of the cover layer, a shiny metallic appearance, from which the introduced motifs stand out in a clearly contrasting manner, especially in transmitted light.

In an alternative, likewise advantageous variant, the metal layer is arranged between the two color layers and has with these congruent recesses, which form at least a part of the introduced into the security element motifs. With particular advantage, the second color layer arranged above the metal layer may have a yellow, reddish brown or brown color, so that a gold-colored or copper-colored color impression is produced when viewed from the side of the cover layer.

In all embodiments, the effect layer expediently has optically variable pigments, preferably liquid-crystal pigments or interference-layer pigments. The effect layer can also have thermochromic properties, ie show a reversible color change at a certain turnover temperature. The turnover temperature is preferably above the ambient temperature, in particular above 25 ° C. For example, under normal conditions, the effect layer can be opaque and become colorless or translucent when heated, thus making it possible to discern information below it. In a further advantageous embodiment, the effect layer has a diffraction structure, in particular in the form of an embossed relief structure. In all variants, the effect layer can be applied over the entire area or only in regions in the form of patterns, characters or codes.

The opaque cover layer and the optically variable effect layer are preferably on a support, in particular a transparent or translucent support, wherein the cover layer and the effect layer are preferably arranged on opposite sides of the transparent or translucent support. In some embodiments, the carrier is needed only for fabrication and may be removed after completion of the security element.

For protection against mechanical or chemical influences, the opaque cover layer is preferably provided with a transparent or translucent protective layer. The protective layer can at the same time form a carrier for the cover layer and the effect layer.

In this context, the carrier or the protective layer can be advantageously provided with further layers, in particular with opaque, translucent or luminescent color layers or with feature layers comprising machine-readable feature substances.

According to an advantageous embodiment of the invention, the security element in addition to the effect layer on a thermochromic layer, which conceals below their envelope temperature, the introduced motifs when viewed from one of the opposite sides partially or completely. In a variant, this thermochromic layer is arranged on the first side of the security element above the opaque cover layer. Alternatively, the thermochromic layer may be disposed on the second side of the security element between the opaque cover layer and the effect layer.

In both cases, the thermochromic layer is preferably formed by a thermochromic liquid crystal layer, preferably with a turnover temperature in the range of 25 ° C to 60 ° C, particularly preferably in the range of 30 ° C to 60 ° C.

The described security elements can be designed, for example, in the form of a security strip, a security thread, a security strip, a label-shaped single element (patch) or a transfer element for application to a security paper, value document or the like.

The invention also includes a security paper for the production of security documents, such as banknotes, identity cards or the like, which is equipped with a security element described above. In particular, the security paper may include at least one continuous window area or a hole covered with the security element is so that the two different visual appearances in the window area or hole are recognizable. The security element can, for example in the form of a window security thread, also be embedded in the security paper in such a way that the optically variable effect is recognizable only in the subregions in which the security element enters the surface of the paper, while the recesses in the opaque cover layer contribute Viewing the security paper in the transmitted light emerge.

The invention further includes a value document equipped with a security element described above, for example a banknote. The value document may also include a window area covered by the security element or a hole covered therewith.

The described security element, security paper or document of value can also be used to secure goods of any kind.

To produce a security element with introduced motifs in the form of patterns, characters or codes, a security element with a superimposed opaque cover layer and a substantially transparent or translucent optically variable effect layer is produced, wherein the motifs are introduced as recesses in the opaque cover layer, so that they can be seen from opposite sides with different visual appearance when viewing the security element. Preferably, the opaque cover layer is applied to a transparent or translucent support or to the optically variable effect layer.

In a first preferred variant of the method, when the opaque cover layer is applied, a first liquid-soluble, preferably Water-soluble ink layer printed, and printed on this first color layer in regions a second, insoluble in the liquid, preferably waterproof ink layer. The first color layer can be printed over the entire surface or even already in the form of a motif. The regions of the first color layer which are not protected by the second color layer are subsequently removed by a washing step with the liquid, so that corresponding recesses are formed in the opaque cover layer. A metal layer is preferably applied to the two color layers before the washing step, in particular vapor-deposited.

In an alternative, likewise advantageous variant, when the opaque cover layer is applied, a first, preferably water-soluble, ink layer is printed in a liquid, a metal layer is applied to the first color layer, in particular vapor-deposited, and then a second, insoluble in the liquid region, on the metal layer , preferably waterproof ink layer printed. The first color layer and the metal layer can be printed over the entire surface or in the form of motifs. Again, the unprotected areas of the first color layer and the metal layer are removed by the subsequent washing step, so that corresponding recesses arise in the opaque cover layer.

In a preferred embodiment of the method, the first ink layer is formed of a water-soluble ink and the second ink layer of a water-resistant ink, so that the washing step can be carried out with water.

Compared to a production of the recesses by means of etching technology, the described method has several advantages. Thus, when using an etching technique, it is difficult to prepare a alkali-resistant resist find that at the same time has a good adhesion to the metallic coating. Also, the use of alkaline solutions for demetallization entails the risk of carryover of alkaline residues within the demetallization plant. By contrast, in the case of the production of security elements described here with a washing process, no alkali-resistant resist coating is required. The demetallization is preferably carried out with water, so that the use of alkaline solutions is avoided. Overall, the method described is simple, inexpensive and environmentally friendly and provides high quality and easy to control results through the use of established printing techniques.

Further exemplary embodiments and advantages of the invention are explained below with reference to the figures, in the representation of which a representation true to scale and proportion has been dispensed with in order to increase the clarity.

Fig. 1

eine schematische Darstellung einer Banknote mit einem eingebetteten Sicherheitsfaden und einem über einer gestanzten Öffnung aufgeklebten Transferelement, jeweils nach einem Ausführungsbeispiel der Erfindung,

Fig. 2

den Schichtaufbau eines Sicherheitselements nach einem Ausführungsbeispiel der Erfindung im Querschnitt,

Fig. 3

in (a) bis (f) sechs Zwischenschritte bei der Herstellung des Sicherheitselements von Fig. 2,

Fig. 4

eine teilweise aufgeschnittene Aufsicht auf die Vorderseite eines Sicherheitselements nach einem anderen Ausführungsbeispiel der Erfindung,

Fig. 5

einen Querschnitt einer Abwandlung des Sicherheitselements von Fig. 2,

Fig. 6

eine Aufsicht auf ein Sicherheitselement nach einem weiteren Ausführungsbeispiel der Erfindung,

Fig. 7

einen Querschnitt durch das Sicherheitselement der Fig. 6 entlang der Linie VII-VII,

Fig. 8

eine Aufsicht auf ein Sicherheitselement nach noch einem weiteren Ausführungsbeispiel der Erfindung,

Fig. 9

in (a) bis (d) Querschnitte durch das Sicherheitselement der Fig. 8 entlang der Linie IX-IX, die Zwischenschritte bei der Herstellung zeigen,

Fig.10 -12

Sicherheitselemente nach weiteren Ausführungsbeispielen der Erfindung im Querschnitt,

Fig.13 -14

weitere Ausführungsbeispiele erfindungsgemäßer Sicherheitelemente, bei denen die eingebrachten Motive mit weiteren Motiven kombiniert sind, die nur oberhalb oder unterhalb einer charakteristischen Umschlagtemperatur in Erscheinung treten,

Fig. 15

einen Querschnitt durch ein erfindungsgemäßes Sicherheitselement, und

Fig.16

einen Querschnitt durch ein erfindungsgemäßes Sicherheitselement.

Show it:

Fig. 1

3 a schematic representation of a banknote with an embedded security thread and a transfer element glued over a punched opening, in each case according to an exemplary embodiment of the invention,

Fig. 2

the layer structure of a security element according to an embodiment of the invention in cross-section,

Fig. 3

in (a) to (f) six intermediate steps in the production of the security element of Fig. 2 .

Fig. 4

a partially cutaway view of the front of a security element according to another embodiment of the invention,

Fig. 5

a cross section of a modification of the security element of Fig. 2 .

Fig. 6

a plan view of a security element according to another embodiment of the invention,

Fig. 7

a cross section through the security element of Fig. 6 along the line VII-VII,

Fig. 8

a plan view of a security element according to yet another embodiment of the invention,

Fig. 9

in (a) to (d) cross sections through the security element of Fig. 8 along the line IX-IX, which show intermediate steps in the production,

Fig. 10-12

Security elements according to further embodiments of the invention in cross section,

Fig.13 -14

further embodiments of security elements according to the invention, in which the introduced motifs are combined with other motifs which only appear above or below a characteristic turnover temperature,

Fig. 15

a cross section through a security element according to the invention, and

Figure 16

a cross section through a security element according to the invention.

The invention will now be explained in more detail using the example of a banknote. Fig. 1 shows a schematic representation of a banknote 10, the two security elements 12 and 16, respectively, which are each formed according to an embodiment of the invention. The first security element represents a security thread 12 that emerges in certain window areas 14 on the surface of the banknote 10, while it is embedded in the intervening areas inside the banknote 10. The bill further has a continuous punched opening 18 which is completely covered on the front of the bill by the glued transfer element 16.

The layer structure and the production of a security element according to the invention, such as the security thread 12 or the transfer element 16, will now be described with reference to FIGS Figures 2 and 3 explains Fig. 2 the layer structure of the security element in cross-section and Fig. 3 in (a) to (f) shows six intermediate steps in the production of the security element.

With reference first to Fig. 3 (a) is printed on a transparent or translucent plastic film 20 over its entire surface an opaque layer 22 of a water-soluble ink. In the exemplary embodiment, the printing ink of the opaque layer 22 has a black color shade with a high proportion of pigments, for example carbon black pigments. The ink has the property not to anchor with the plastic film 20 so that they can be removed later with water as a solvent again.

On the opaque color layer 22, a second, waterproof ink layer 24 is partially printed, as in Fig. 3 (b) shown. The color layer 24 covers the ink layer 22 well in the applied areas, so that they can not be washed off there. For example, the ink of the second ink layers 24 may partially penetrate the first ink and anchor it to the plastic film. The color layer 24 is not applied over the entire surface, but with recesses 26 in the form of the desired motifs.

For better distinctness, the printing ink of the second ink layer 24 may have a different hue than the first ink. For example, the first ink may have a black color and the second ink a blue color. However, first and second printing inks can also have the same color tone, for example black, which, however, results in a lower distinctness of the two color layers 22 and 24 when assessing the print quality. The printing ink of the second ink layer 24 can also contain machine-readable feature substances, in particular magnetic and / or electrically conductive feature substances.

A metallic coating 28, in the exemplary embodiment aluminum, is then applied to the two color layers 22, 24, as in FIG Fig. 3 (c) shown. Other, preferably aufdampfbare metals or alloys are eligible for the coating 28 in question. After metallization, the first color layer 22 and the metal layer 28 in the recesses 26 are removed with a suitable solvent, in the exemplary embodiment water. It is exploited that the first ink forms a raised paint on the plastic film 20 by the high pigment content after drying. The metal layer 28 therefore only partially covers the dried color body of the first printing ink in the recesses 26, so that it remains accessible to the solvent in these areas. The application of paint in the recesses 26 is washed out together with the overlying metal layer 28. The washing step can also be done with mechanical assistance.

Outside the recesses 26, the first color layer 22 remains on washing, protected by the waterproof second color layer 24, as shown in FIG Fig. 3 (d) shown. The two color layers 22, 24 together with the metal layer 28 now form an opaque cover layer 30 into which the desired motifs in the form of patterns, characters or codes are introduced. At this stage of manufacture, the motifs can already be seen from both sides of the coated plastic film, whereby they appear as negative information in an otherwise metallic appearance or an otherwise black appearance, depending on the viewing direction.

To protect the structured cover layer 30, the coated side of the plastic film 20 is laminated with a transparent or translucent plastic support 32 and a laminating adhesive 34, as in FIG Fig. 3 (e) shown. The metallic coating 28 is thereby protected against mechanical and chemical influences.

On the non-printed or uncoated side, the plastic film 20 is then laminated with a further plastic carrier 36, which was previously provided with a substantially transparent or translucent optically variable effect layer 38. In the embodiment, the effect layer 38 is formed by a liquid crystal layer, for example, a cholesteric liquid crystal layer having a color shift effect. Subsequently, the plastic carrier 36, as in Fig. 3 (f) shown separated from the effect layer 38, and the security element tailored and reworked according to the application. When used as a security thread in a banknote, the security element is provided, for example, for better adhesion in the paper on both sides with a heat seal adhesive.

Overall, results from the in 3 (a) to (f) illustrated method steps the security element of Fig. 2 , in which the introduced motifs are recognizable from both sides with different optical impression. The security element of Fig. 2 For example, the security thread 12 can be inserted in the correct direction into a document material, here the paper of the banknote 10, so that the optically variable effect of the security thread in the subregions 14 appears on the surface of the banknote. The metallic side of the security thread 12 is completely embedded in the paper to reduce the visibility of the security thread on the back of the paper.

In this, as well as the subsequent embodiments, when printing the water-soluble ink 22, no high application amount is required, so that they can be applied over the entire surface in a lighter, non-opaque color. On the other hand, the insoluble ink 24 is preferably dark, especially black, so that it is easily possible to check the quality of the areas printed with the insoluble ink 24. This is especially important when printing lettering or number sequences.

Some types of security thread require the correct thread insertion in the paper for the purpose of thread visibility, so that an opaque white layer is printed on one side of the film. The recesses appear rather opaque due to the opaque whitening layer as compared to demetalized threads which do not require a laterally correct insertion. If a white wash ink is used as the water-soluble printing ink 22, then the security element on this page shows transparent relief patterns. For the insoluble ink 24 is then to select a hue that does not affect the white wash color in the shade too much.

Fig. 4 shows a partially cutaway plan view of the front of a security element 40 according to a further embodiment of the invention, in which between the recesses 26 in the cover layer 30, a further printing ink is printed with machine-readable properties. For example, as in Fig. 4 schematically shown, with a printing ink having magnetic properties, a visually unrecognizable, machine-readable streak code 42 may be printed between the recesses 26 to further increase the anti-counterfeiting security of the element.

In a respect to Fig. 5 explained modification of the security element of Fig. 2 a transparent or translucent plastic film 220 is provided with an opaque cover layer 230 which consists of a sequence of a water-soluble printing ink 222 applied over the entire surface, an aluminum layer 228 vapor-deposited on the printing ink 222 and a water-insoluble printing ink 224 partially printed on the aluminum layer 228. The water-insoluble printing ink 224 in this case has a yellow or reddish-brown color, so that, in interaction with the aluminum layer 228, when viewed from the metallised side, a gold-colored or copper-colored color impression is produced here.

As related to the Figures 2 and 3 described, the cover layer 230 is laminated after partial demetalization by washing the ink 222 with a translucent plastic support 232 to protect the printed metal layer 228 against mechanical and chemical influences. Also, the non-printed side of the film 220 is provided with an effect layer 238.

Another embodiment of the invention will now be described with reference to FIG FIGS. 6 and 7 explains Fig. 6 a supervision and Fig. 7 a cross section through the security element along the line VII-VII of Fig. 6 shows.

The security element 50 comprises a translucent plastic layer 52 to which, as described above, a structured cover layer 54 is applied. The cover layer 54 consists of identically or differently colored washable and preferably water-soluble inks 56 and 58, printed on it from the same or different types of insoluble printing inks 60 and 62 and a metallic coating 64th

The printing inks 56 and 58 can be arranged, for example, in different colors, so that in supervision a security element with differently colored blocks 66 or 68 (FIG. Fig. 6 ), which may have various transparent recesses in the form of characters, patterns or codes. Also, the insoluble inks 60 and 62 may be the same or different. For example, the ink 60 may have machine readable properties in the form of magnetic and / or electrically conductive properties while the ink 62 has no machine readable properties. In other configurations, the insoluble inks 60, 62 both have magnetic properties that However, they differ, for example, in remanence or coercivity. Also, one printing ink may have hard-magnetic properties, the other printing ink soft-magnetic properties.

The security element 50 further contains a primer layer 70 to which further printing inks 72 and 74 are applied in the region of the left-over areas of the cover layer 54. The printing inks 72 and 74 may also have the same or different properties and, for example, be opaque or translucent. They may also have the same or different fluorescent feature substances, such that the recesses in the cover layer 54 fluoresce when illuminated with UV radiation in the corresponding colors.

On the opposite side of the plastic layer 52, the security element 50 is provided with an optically variable effect layer 76. In the embodiment, the effect layer is formed by a thermochromic layer which is opaque below a certain Umschlagtemperatur, for example 30 ° C. Above the turnover temperature, the thermochromic layer 76 becomes colorless or translucent, so that only the underlying information can be recognized.

Alternatively, the effect layer 76 may be in the form of a directionally reflective layer, for example a translucent layer, which generates different color impressions as the viewing angle changes in reflection. Such optically variable properties can be obtained, for example, with interference layer pigments or liquid crystal pigments which are admixed to a transparent binder or a transparent plastic film. In a further variant, the optically variable effect of the effect layer 76 is produced by a relief structure, which is impressed on a transparent lacquer or plastic layer in the form of diffraction structures.

The translucent plastic layer 52 may also be provided with a metal layer, which may be embodied either over the entire area or at least in areas in the form of a grid with a predetermined grid size and grid width. The grid elements can consist of points, lines or other, even irregular, geometric shapes.

From layer edge to layer edge of the security element, a transparent region with electrically conductive properties can furthermore be arranged, which offers a further possibility of coding. In such a transparent region, for example, in the inset process, also other printing inks, such as flag colors, can be arranged.

FIGS. 8 and 9 illustrate another embodiment of the invention, wherein Fig. 8 a supervision and Fig. 9 in (a) to (d) shows cross sections through the security element along the line IX-IX for intermediate steps in the production of the security element.
The security element 80 has first regions 82 with diffraction structures and transparent recesses 84 and second colored regions 86 with transparent recesses 88.

In order to produce the various regions, a stamping layer 92 is applied to a carrier material or transfer material made of a plastic layer 90. Embossed into the embossing layer 92 is a relief structure which, in interaction with the subsequently applied metallization in reflection, produces a diffraction-optical image, for example a hologram or a lattice structure, such as a Kinegram or a Pixelgram.

Over the embossing layer 92, a water-soluble printing ink 94 in the form of patterns, characters or codes is then applied in individual blocks. The water-soluble printing ink 94 is applied both in the colored areas 86 including their recess areas 88 and in the recess areas 84 of the diffraction pattern areas 82, as in FIG Fig. 9 (a) shown.

Subsequently, as in Fig. 9 (b) 4, the waterproof ink 96 in the colored areas 86 in the register is printed on the blocks of the water-soluble ink 94, leaving the recessed areas 88 of the colored areas 86 exposed. In the diffraction structure regions 82, no waterproof ink is applied. Then, the entire structure is coated with a metal layer 98, preferably aluminum, as in Fig. 9 (c) shown. Instead of aluminum, other metals, such as copper, gold, iron, chromium, nickel, silver, platinum, palladium, titanium, other non-ferrous metals, or suitable alloys for the coating into consideration.

By washing out the water-soluble ink 94, the security element is partially demetallized, so that the in Fig. 9 (d) shown structure arises. In the diffraction structure regions 82, diffraction patterns of the metallized relief structure can be seen in reflection, with the recess regions 84 appearing transparent. The recesses 88 in the colored areas 86 are visible from both sides.

As described in detail above, the back of the plastic layer 90 is subsequently still with a in Fig. 9 not shown, optically variable effect layer, so that the images formed by the recesses 88 viewed from the back with an optically variable effect in appearance.

Figure 10 shows a security element 100 according to a further embodiment of the invention. In the security element 100, a transparent plastic carrier 116 is coated with an optically variable effect layer 102, for example in the form of a directionally reflecting layer with liquid crystal pigments. On this optically variable effect layer 102, a structured cover layer 104 is arranged, which, as in connection with the Figures 2 and 3 described, consists of a sequence of initially applied over the entire surface water-soluble ink 106, a partially printed water-insoluble ink 108 and a vapor-deposited metal layer 110, in particular aluminum.

After partial demetalization by washing out the ink 106 in the unprotected areas, the cover layer 104 is laminated with a translucent plastic support 112 by means of a laminating adhesive 114, so that the metal layer 110 is protected against mechanical and chemical influences. Finally, the carrier film 116 is peeled off and separated from the optically variable effect layer 102. Depending on the application and specific embodiment of the effect layer 102, it may be advantageous to subsequently protect these also against mechanical and chemical influences.

The design of the Fig. 10 has the advantage, in particular for viewing from the rear side compared with the exemplary embodiments described above, that there are no intermediate layers, such as an adhesive layer or a film, between the optically variable effect layer 102 and the substrate formed by the printing inks 106 and 108. The optically variable effect is therefore particularly evident.

Over the effect layer 102 can also in the embodiment of the Fig. 10 be arranged a stamping layer. If the embossing layer lies between the effect layer 102 and the carrier film 116, then a release layer is used to enable a problem-free separation of carrier film 116 and effect layer 102. Even within the effect layer 102 embossed motifs may be provided.

In the security element 120 of Fig. 11 a translucent plastic carrier 122 is provided with a stamping layer 124, which may be formed as indicated above. On the embossing layer 124, a structured covering layer 126 is arranged, which in turn consists of a sequence of a water-soluble printing ink 128 applied over the entire surface, a water-insoluble printing ink 130 printed in certain regions, and an aluminum layer 132. After the partial demetallization by washing out the printing ink 128 and lamination of the cover layer 126 with a translucent plastic support 134 by means of laminating adhesive 136, the aluminum layer 132 is protected against mechanical and chemical influences.

Subsequently, a further carrier foil 140 with an optically variable effect layer 142, for example a directionally reflecting layer of liquid crystal pigments, is applied on the side of the plastic carrier 122 facing away from the cover layer 126 by means of laminating adhesive 144. Then, the further carrier film 140 is separated from the effect layer 142. The security element 100 then shows, in addition to the color shift effect of the liquid crystal layer 142, which can be recognized from the rear side, an optically variable effect, which is formed by the embossing motif of the embossing layer 124, from the front side. This embossed motif is clearly visible against the dark background of the printing inks 128 and 130 depending on the viewing angle and can therefore serve as an additional authenticity feature.

Another security element according to an embodiment of the invention is in Fig. 12 shown. In the case of the security element 150, first of all a water-soluble printing ink 154 is imprinted on a translucent plastic substrate 152 and a metal layer 156 is vapor-deposited on the printing ink 154, also over the entire surface. Thereafter, printed on the metal layer 156 is a waterproof ink 158 with recesses 160 in the form of patterns, characters or codes. The printing ink 158 may be provided with machine-readable feature substances, for example magnetic and / or electrically conductive particles.

In the exemplary embodiment, a further printing layer 162 with machine-readable properties is additionally provided, which is applied between the recesses 160 of the waterproof printing layer 158. After the partial demetallization by the washing step, an optically variable effect layer 164 present on a carrier film is transferred onto the security element 150 with a laminating adhesive 166. Finally, the carrier film is peeled off and the in Fig. 12 achieved situation.

When using a water-soluble ink 154 with a white hue, the security element is less visible when embedded in paper from the back. An additional opaque white layer, which has been required for some thread types so far, can therefore be omitted.

Figures 13 and 14 show further embodiments of security elements according to the invention, in which the recesses introduced into the opaque cover layer motifs are combined with other motifs, which occur only above or below a characteristic Umschlagtemperatur in appearance. The other motifs can be above or below the envelope temperature also affects the visibility or background of the recessed motifs of the topcoat.

Fig. 13 shows a security element 170 according to the invention with a translucent plastic layer 172 on which a thermochromic liquid-crystalline ink 174 over the entire surface or, as in the embodiment, only partially arranged in the form of a motif.

The thermochromic liquid-crystalline color shows a color change when heated above the transition point, which makes the motif visible on the security element. When cooled, the motif disappears again. The process is reversible and can be repeated as often as desired. Thermochromic liquid-crystalline inks are available with a color change range between -30 ° C and 120 ° C with a bandwidth of 0.5 ° C to 30 ° C. For use in security elements, the turn-up area is preferably above the ambient temperature, in particular in the range of 25 ° C to 60 ° C, preferably between 30 ° C and 60 ° C.

On the thermochromic liquid-crystalline ink layer 174, a black ink 176 is provided with recesses in the form of characters, patterns or codes, which may be formed with or without machine-readable feature substances. On the printing ink 176, a second liquid-crystalline layer 178 is arranged as an effect layer, which is applied by means of a laminating adhesive 180. As already described, the carrier film, on which the effect layer 178 is first applied, is removed again after laminating.

A further embodiment of a security element 190 according to the invention is shown in FIG Fig. 14 shown. On the front of the transparent plastic carrier 192, a cover layer 194 is arranged in the manner described above and protected by lamination with another, not shown, transparent support. On the non-printed side of the plastic carrier 192, a thermochromic liquid-crystalline ink layer 196 is arranged over the entire surface or only in regions. In addition, a second liquid-crystalline layer 198 is arranged as an effect layer over the thermochromic liquid-crystal layer 196, which produces a color impression which varies depending on the viewing angle.

In addition to the recesses of the cover layer 194 that can be seen in the transmitted light, the security element 190 thus exhibits a color shift effect in reflected light when viewed from the underside. Upon heating of the security element over the turn-over temperature of the thermochromic ink layer 196, a motif is visible, which is given by the recesses of the cover layer 194. From the other side, the security element shows a metallization to the back cover.

The security elements of Figures 13 and 14 can of course also be provided with luminescent and / or machine-readable properties, for example by means of magnetic and / or electrically conductive feature substances. A combination of visually verifiable, machine-readable and thermochromic properties gives the security element additional counterfeit security. The latter security elements can also be combined with embossing stories.

Fig. 15 shows a further embodiment of a security element 250 according to the invention in cross section. On the plastic support 239 a waterproof ink 240 is applied with recesses. The waterproof ink 240 is preferably a high gloss silver ink. Over this printing ink 240, a water-soluble printing ink 241 is arranged over the entire surface during the production process, which is well anchored on the waterproof printing ink 240, but not on the plastic substrate 239. Over the ink layer 241, a further printing ink 242 is arranged over the entire surface. The second color layer 242 may additionally contain machine-readable feature substances. Over the color layers 240, 241 and 242, a metallic coating 243, preferably aluminum, is applied over the entire surface. Now, if the corresponding structure is treated with water, the layers 241, 242 and 243 remain adhered only to the areas which are printed with the color 240. In the areas not printed with the ink 240, the ink layers 241, 242 and 243 are removed by the washing process. This gives a security element with machine-readable properties and transparent recesses, whereby the print layer, which is usually darkened by the machine-readable feature substance, is not visible to the eye. In a further variant, between the printing ink 240 and 241, a further layer (not shown) may be arranged, which has fluorescent properties. This layer can be arranged both over the entire surface as well as partially. If the layer is arranged over the entire surface, one obtains a security element in which the recesses appear fluorescent with appropriate illumination.

Layer 245 is an optically variable effect layer.

Fig. 16 describes a security element 260 according to the invention in the form of a transfer element, in which a translucent plastic carrier 262 is provided with a stamping layer 264. In the embossing layer 264, a relief structure is embossed (not shown) which, in interaction with the subsequently applied metallization in reflection, produces a diffraction-optical image. On the embossing layer 264 is a water-soluble ink 266th (not shown) with recesses applied. About the ink 266, a metal layer 268 over the entire surface, preferably of aluminum, applied. By washing out the water-soluble ink 266, the security element is partially demetallized, so that the in Fig. 16 shown structure arises. On the now partially existing metal layer, a black ink is applied 270. The now printed and metallized film side is laminated together with the aid of a laminating adhesive 272 with a further carrier film 276 to which an optically variable effect layer 274 has previously been applied. The carrier film 276 can be removed again after the laminating process. Over the effect layer 274, a lacquer can be applied, with which the adhesion to a value document is later achieved. After the transfer to the document of value, the plastic carrier 262 can optionally be removed. The security element 260 according to the invention shows on one side of the film a diffraction effect with recesses and on the other side of the film an effect layer with congruent recesses. This security element is preferably applied over a hole on a document of value, so that both described sides of the film are visible to the viewer. Of course, the security element 260 can also be introduced into the paper in the form of a window security thread during paper production. In this case, the two carrier sheets 262 and 276 are not peeled off.

Claims (40)

1. A security element (12,16) for security papers (10), value documents and the like, having, introduced into the security element, motifs in the form of patterns, characters or codes, the motifs, when the security element is viewed from opposing sides, being perceptible having a different optical appearance, the motifs, when viewed from a first side, being perceptible as gaps (26) in an opaque cover layer (30), and when viewed from the second, opposing side through a substantially transparent or translucent optically variable effect layer (38), appearing having an optically variable effect, characterized in that the opaque cover layer comprises two stacked ink layers, of which a first ink layer is soluble in a liquid, and the second ink layer is insoluble in the liquid.
2. The security element according to claim 1, characterized in that the first ink layer is water soluble and the second ink layer is waterproof.
3. The security element according to claim 1 or 2, characterized in that the first ink layer comprises a high pigment content.
4. The security element according to at least one of claims 1 to 3, characterized in that the first ink layer comprises sub-regions having a different color impression.
5. The security element according to at least one of claims 1 to 4, characterized in that the second ink layer is formed on a nitrocellulose, polyamide, PVC or UV basis.
6. The security element according to at least one of claims 1 to 5, characterized in that the second ink layer includes machine-readable feature substances, especially luminescent, magnetic and/or electrically conductive feature substances.
7. The security element according to at least one of claims 1 to 6, characterized in that the second ink layer comprises sub-regions having a different color impression and/or sub-regions having different machine-readable feature substances.
8. The security element according to at least one of claims 1 to 7, characterized in that the first and/or second ink layer has a dark hue, especially black.
9. The security element according to at least one of claims 1 to 8, characterized in that the first and second ink layer comprise congruent gaps that form at least a portion of the motifs introduced into the security element.
10. The security element according to at least one of claims 1 to 9, characterized in that the opaque cover layer comprises a metal layer.
11. The security element according to claim 9 and 10, characterized in that the metal layer is arranged over the two ink layers and comprises, congruent with the gaps in said ink layers, gaps that form at least a portion of the motifs introduced into the security element.
12. The security element according to claim 9 and 10, characterized in that the metal layer is arranged between the two ink layers and comprises, congruent with the gaps in said ink layers, gaps that form at least a portion of the motifs introduced into the security element.
13. The security element according to claim 12, characterized in that the second ink layer arranged over the metal layer has a yellow, reddish-brown or brown hue.
14. The security element according to at least one of claims 10 to 13, characterized in that the metal layer consists of aluminum, copper, gold, iron, chrome, nickel, silver, platinum, palladium, titanium, another non-ferrous metal, or an alloy of said metals.
15. The security element according to at least one of claims 1 to 14, characterized in that the effect layer comprises optically variable pigments, preferably liquid crystal pigments or interference layer pigments.
16. The security element according to at least one of claims 1 to 15, characterized in that the effect layer is thermochromic, preferably having a color-change temperature above 25°C.
17. The security element according to at least one of claims 1 to 16, characterized in that the effect layer includes a diffraction pattern, especially in the form of an embossed relief pattern.
18. The security element according to at least one of claims 1 to 17, characterized in that the effect layer is developed in the form of patterns, characters or codes.
19. The security element according to at least one of claims 1 to 18, characterized in that the opaque cover layer and the optically variable effect layer are present on a substrate, especially a transparent or translucent substrate.
20. The security element according to claim 19, characterized in that the cover layer and the effect layer are arranged on opposing sides of the transparent or translucent substrate.
21. The security element according to at least one of claims 1 to 20, characterized in that the opaque cover layer is furnished with a transparent or translucent protective layer.
22. The security element according to claim 21, characterized in that the protective layer simultaneously forms a substrate for the cover layer and the effect layer.
23. The security element according to at least one of claims 19 to 22, characterized in that the substrate or the protective layer are furnished with additional layers, especially with opaque, transparent or luminescent ink layers or with feature layers that comprise machine-readable feature substances.
24. The security element according to at least one of claims 1 to 23, characterized in that the security element comprises, in addition to the effect layer, a thermochromic layer that, below its color-change temperature, conceals the introduced motifs when viewed from one of the opposing sides.
25. The security element according to claim 24, characterized in that the thermochromic layer on the first side of the security element is arranged over the opaque cover layer.
26. The security element according to claim 24, characterized in that the thermochromic layer on the second side of the security element is arranged between the opaque cover layer and the effect layer.
27. The security element according to at least one of claims 24 to 26, characterized in that the thermochromic layer is formed by a thermochromic liquid crystal layer, preferably having a color-change temperature in the range from 25°C to 60°C, particularly preferably in the range from 30°C to 60°C.
28. The security element according to at least one of claims 1 to 27, characterized in that the security element forms a security strip, a security thread, a security band, a patch or a transfer element for application to a security paper, value document and the like.
29. A security paper for manufacturing security documents, such as banknotes, identification cards or the like, that is furnished with a security element according to at least one of claims 1 to 28.
30. The security paper according to claim 29 having at least one window area or hole that is covered with the security element.
31. A value document, such as a banknote, identification card or the like, that is furnished with a security element according to at least one of claims 1 to 28.
32. The value document according to claim 31 having at least one window area or hole that is covered with the security element.
33. A use of a security element according to at least one of claims 1 to 28, of a security paper according to claim 29 or 30, or of a value document according to claim 31 or 32 for securing goods of any kind.
34. A method for manufacturing a security element having introduced motifs in the form of patterns, characters or codes, characterized in that a security element having an opaque cover layer and a substantially transparent or translucent optically variable effect layer arranged one on top of the other is produced, the opaque cover layer being formed by two stacked ink layers, of which a first ink layer is soluble in a liquid, and a second ink layer is insoluble in the liquid, and the motifs being introduced as gaps in the opaque cover layer such that, when the security element is viewed from opposing sides, they are perceptible having a different optical appearance.
35. The method according to claim 34, characterized in that the opaque cover layer is applied to a transparent or translucent substrate or to the optically variable effect layer.
36. The method according to claim 35, characterized in that, upon application of the opaque cover layer, the first ink layer, which is soluble in the liquid and is preferably water soluble, is imprinted, and on the first ink layer is imprinted in some regions the second ink layer, which is insoluble in the liquid and is preferably waterproof.
37. The method according to one of claims 34 to 36, characterized in that a metal layer is applied to, especially vapor deposited on, the two ink layers.
38. The method according to claim 35, characterized in that, upon application of the opaque cover layer, the first ink layer, which is soluble in the liquid, preferably is water soluble, is imprinted, a metal layer is applied to, especially vapor deposited on, the first ink layer, and then on the metal layer is imprinted in some regions the second ink layer, which is insoluble in the liquid, preferably is waterproof.
39. The method according to at least one of claims 34 to 38, characterized in that, in a wash step, the first ink layer and the metal layer lying over it are removed in the regions not protected with the second ink layer, causing gaps in the form of the motifs to be formed in the opaque cover layer.
40. The method according to claim 39, characterized in that the first ink layer is formed from a water-soluble printing ink and the second ink layer from a waterproof printing ink, and in that the wash step is carried out with water.

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