WO2015117765A1

WO2015117765A1 - Producing a security element having color changing properties

Info

Publication number: WO2015117765A1
Application number: PCT/EP2015/000265
Authority: WO
Inventors: Winfried HOFFMÜLLER; Theodor Burchard; Patrick ENGELMANN; Christian Fuhse
Original assignee: Giesecke & Devrient Gmbh
Priority date: 2014-02-07
Filing date: 2015-02-06
Publication date: 2015-08-13
Also published as: CA2935427C; DE102014001688A1; CA2935427A1; CN105916697B; EP3102420B1; EP3102420A1; CN105916697A

Abstract

The invention relates to a method for producing a security element, the method comprising the steps: Providing a carrier material (200, 300, 400, 500) having at least one region (106, 202, 302, 402, 502, 606) to be coated; arranging a reflection layer (204, 304, 410) in the region to be coated; arranging a structured spacer layer (206, 306, 412) on the reflection layer, wherein the structured spacer layer is suited to protect the reflection layer from a removal; arranging an absorber layer (212, 312, 416, 512) at least on the structured spacer layer; and removing the reflection layer in those regions, where the removal of the reflection layer is not obstructed by the protection of the structured spacer layer. The invention further relates to a security element produced by using said method, and to a value document having a security element such as this.

Description

Production of a security element with color change properties

The invention relates to a method for producing a security element as well as a security element and a security document containing security element.

Value documents within the meaning of the invention include banknotes, stocks, bonds, certificates, vouchers, checks, air tickets, high-quality entrance tickets, labels for product security, credit or debit cards, but also other forgery-prone documents, such as passports, ID cards or other identity documents.

Value documents, in particular bank notes, are usually made of paper substrates, polymer substrates or combinations of paper and polymer which have special security features, such as a security thread at least partially incorporated into the paper or a watermark. As a further security feature, so-called window films, security threads, tapes can be glued / laminated or introduced onto the document of value. Security elements usually comprise as a base material a polymer or polymer compositions. Typically, security features have optically variable security features such as holograms or certain color-shift effects to provide better anti-counterfeit security. The particular advantage of optically variable security elements is that the security features on these security elements can not be mimicked by mere copying with copiers, since effects of an optically variable security feature are lost through copying or even appear only black. In the case of existing value documents with optically variable security elements which exhibit color shift effects (color shift effects), however, it is disadvantageous that the production of the thin-film elements required for this purpose is very time-consuming and cost-intensive. For example, when producing a thin-film element by means of physical vapor deposition, in particular the production of the necessary spacer layer is very time-consuming. With regard to a definition and mode of operation of thin-film elements, reference is made by way of example to the publications WO 2009 / 149831A2 and WO2011 / 032665 AI.

Furthermore, the introduction of additional security features such as so-called. Negative patterns or negative text in the field of Farbkippeffekte / thin-film elements consuming and often qualitatively unsatisfactory. For example, the introduction of negative patterns in a region with a color-shift effect requires that the layers of the thin-film element leading to the color-shift effect must be at least partially removed at the locations at which the negative patterns are to be introduced. It is therefore an object of the present invention to provide a method which makes it possible to produce security elements with optically variable effects with less time and expense.

It is also an object of the present invention to provide a method which makes it possible to produce security elements with optically variable effects and additional negative patterns in high quality. These objects are achieved by the subject matters of the independent claims. Preferred embodiments are defined in the dependent claims. A first aspect of the invention relates to a method for producing a security element comprising the steps:

Providing a support material having at least one area to be coated;

Arranging a reflection layer in the area to be coated; Arranging a patterned spacer layer on the reflective layer, wherein the patterned spacer layer is adapted to protect the reflective layer from being removed;

Arranging an absorber layer at least on the structured spacer layer; and

Removing the reflective layer in the areas in which the removal of the reflective layer is not prevented by the protection of the structured spacer layer.

The carrier material may have one or more areas to be coated. A carrier material preferably comprises two major surfaces facing each other. The carrier material is preferably a film-like material. The at least one region to be coated is preferably arranged on a main surface of the carrier material. If the carrier material has a plurality of regions to be coated, these can be arranged only on one of the two main surfaces or on both main surfaces of the carrier material.

The region of the Trägermäterials to be coated may have different surface shapes. For example, the area to be coated be rectangular, oval, star-shaped or serpentine. The shape and size of the area to be coated is preferably defined or determined in one method step. The region of the carrier material to be coated may have a surface structure and / or surface texture which differs from other regions of the carrier material. In other words, the substrate has an area defined as an area to be coated.

The step "arranging a reflection layer in the area to be coated" preferably comprises that the reflection layer is arranged or applied to / on / above the area of the carrier material defined as being to be coated.

Preferably, the reflective layer is arranged or applied over the whole area in the area to be coated. Preferably, the reflective layer can also be arranged in other than the area to be coated. The reflection layer can be applied or vapor-deposited, for example, by means of physical vapor deposition. Further preferably, the reflective layer can also be applied by printing technology. The thickness of the reflection layer is preferably in the range of 5 nm to 200 nm, preferably 5 nm to 100 nm, particularly preferably 5 nm to 50 nm.

Preferably, the step of arranging a patterned spacer layer on the reflective layer, wherein the patterned spacer layer is adapted to protect the reflective layer from being removed, is such that, after disposing the patterned spacer layer, the reflective layer is substantially sandwiched between the substrate and the substrate structured distance view is arranged. In particular, a structured spacer layer is to be understood as meaning that the spacer layer is not arranged uniformly or over the whole area at / above the reflective layer. In other words, after being arranged, a structured spacer layer does not have the same layer thickness or height at every point of the region to be coated. Rather, due to the structured spacer layer, there are sites / subregions in the region to be coated in which the layer thickness of the patterned spacer layer is zero. After arranging the structured spacer layer on the reflective layer, there are two different regions or sections in the region to be coated, namely

first regions / sections comprising the substrate, the reflective layer and the patterned spacer layer, and

second regions / sections which comprise the carrier material and the reflection layer, but no structured spacer layer or a structured spacer layer with too small a layer thickness, so that the reflection layer in these second regions is not protected by the structured spacer layer. In other words, in this case the reflective layer is only partially covered by the structured spacer layer or is arranged one above the other only in some subregions of the region to be coated.

The structured spacer layer is suitable for protecting the reflective layer from being removed. In other words, the structuring of the structured spacer layer specifies in which (sub) regions of the region to be coated the reflective layer can be removed / detached / dissolved / removed. The structured spacer layer thus serves as a mask to allow selective removal of the reflective layer. Advantageously, therefore, the reflection layer can be removed only where the structured spacer layer has not been arranged or falls below a minimum layer thickness or height. Thus, due to the structure of the patterned spacer layer, the reflective layer is protected from being removed in selected areas (sub-areas) in the area to be coated.

Preferably, the patterned spacer layer forms a predetermined motif, such as a character, string, and / or image. This motif or pattern determines the structure of the structured spacer layer. For example, the subject may be visible or recognizable to a viewer when the viewer is looking in the direction of the main surface normal or perpendicular to the main surface of the substrate having the area to be coated.

The step "arranging an absorber layer at least on the structured spacer layer" is to be understood such that the absorber layer is in any case arranged on / above the structured spacer layer. In other words, in this case, the absorber layer is arranged over the whole area in the area to be coated.

The step "removing the reflective layer in the areas in which the removal of the reflective layer is not prevented by the protection of the structured spacer layer" comprises in particular the cases: Removing the reflective layer in the (sub) regions where the patterned spacer layer is not disposed;

Removing the reflective layer in the (sub) regions of the reflective layer not covered by the structured spacer layer; Removing the reflection layer in the (sub) regions in which the structured spacer layer falls below a minimum layer thickness, so that there is no protection against removal by the structured spacer layer in these subregions / regions. In other words, the reflective layer is not removed where the patterned spacer layer acts as a mask.

Advantageously, the structure of the patterned spacer layer dictates in which (sub-) areas of the area defining the area to be coated, the reflective layer can be removed. Thus, the reflective layer can be selectively removed although the agent used for removal is applied to the entire area or non-selectively in the area to be coated. For example, the means used for removal may be a laser beam of areal cross-section (eg 1 cm ² ) with the entire area to be coated treated with the laser beam but only in the areas / (sub) areas not protected by the structure of the patterned spacing layer a removal of the reflection layer is possible. If, for example, an etchant is used to remove the reflection layer, the security element can be completely immersed in the etchant or brought into contact with the etchant, wherein, due to the structure of the structured spacer layer, removal of the reflective layer is possible. Onsschicht can take place only where the (predetermined) structure of the structured spacer layer does not prevent the removal /.

In other words, the structured spacer layer serves as an etching mask or exposure mask.

Accordingly, after removal of the reflective layer in the regions in which the removal of the reflective layer is not prevented by the protection of the structured spacer layer, the following ranges are present:

Regions including the reflective layer, the patterned spacer layer, and the absorber layer; these areas may also be referred to as thin-film element areas; and

Areas that do not contain a reflective layer or a spacer layer; These areas can also be referred to as negative pattern areas.

In particular, the layer sequence forms the reflection layer, the structured spacer layer and the absorber layer, wherein the structured spacer layer is arranged between the reflection layer and the absorber layer, a color shift-thin-film structure or a color-shift thin-film element. Depending on the layer thicknesses of the reflection layer, the structured spacer layer and the absorber layer, see-through color effects may also be present instead of color-shift effects.

Preferably, the step "arranging an absorber layer ..." (temporally) before the step "removing the reflective layer ..." is made. In this refinement, the absorber layer is preferably arranged both on the structured spacer layer and on (sub) regions / partial regions of the reflection layer. In other words, in (sub) regions of the region to be coated, so-called second regions / second regions are present, in which the absorber layer is arranged directly on the reflection layer. Consequently, in this case, by removing the reflective layer, the absorber layer is removed in the (sub) regions in which the patterned spacer layer has not been disposed. In other words, there are no reflective layer, no spacer layer and no absorber layer in these subregions. These subareas are negative pattern areas. Subregions containing a reflective layer, a spacer layer, and an absorber layer are thin film element regions. Advantageously, the reflective layer can be removed where the absorber layer is disposed directly on the reflective layer when the absorber layer is permeable to the removal agent such as irradiation and / or etchant. Preferably, the absorber layer is porous or holy, so that the absorber layer does not form a barrier to the removal agent.

The simultaneous removal of the absorber layer and the reflection layer in only one process step is particularly advantageous since this can drastically reduce the production time and the production costs of security elements with a color shift effect or thin-film elements which additionally contain negative patterns.

Preferably, the absorber layer has a thickness / height of 2 nm to 15 nm, since the permeability of the absorber layer for removing the reflection layer is influenced by the thickness of the absorber layer. Particularly preferably, the method for producing a security element comprises the steps:

Providing a support material having at least one area to be coated;

Fully arranging a reflection layer in the area to be coated;

Arranging a patterned spacer layer on the reflective layer, wherein the patterned spacer layer is adapted to protect the reflective layer from being removed;

Full-surface placement of an absorber layer in the area to be coated;

Simultaneously removing the reflective layer and the absorber layer in the regions in which the removal of the reflective layer is not prevented by the protection of the structured spacer layer.

The entire area of an absorber layer is arranged in the region to be coated in such a way that the structured spacer layer is arranged between the absorber layer and the reflection layer, and in the regions in which the structured spacer layer is absent, the absorber layer is arranged directly on the reflection layer.

It is particularly advantageous that the reflection layer and the absorber layer can be applied / arranged over the whole area in the area to be coated, and yet can be selectively removed in regions by a single process step of "removal." It is also advantageous that the reflection layer and the absorber layer in the areas in which the structured spacer layer is present, not in the Advantageously, the absorber layer is porous or permeable for a corresponding removal agent, so that the reflection layer is detached or dissolved in the regions in which the reflection layer directly adjoins the absorber layer At the same time, in the regions in which the structured spacer layer lies between the absorber layer and the reflection layer, the reflection layer is protected by the structured spacer layer Absorber layer is permeable even in these areas for a corresponding removal agent, but the structured removal layer is not attacked by the corresponding removal agent.According to one example can be selected as the absorber layer chromium, as a structure ized spacer layer, a printing ink with good flow, for example based on nitrocellulose, can be selected, as a reflection layer, aluminum can be selected. In this case, caustic soda or phosphoric acid, for example, which penetrates the chromium and dissolves the aluminum, while the binder or the ink for the structured spacer layer is not impaired, can be used as etchant.

In particular, the absorber layer and / or the reflection layer can be applied by printing technology. Alternatively, it is preferable to perform the step of removing the reflective layer (temporally) before the step of disposing the absorber layer. In this alternative, the absorber layer is preferably arranged only in the (sub) regions in which the structured spacer layer is present. In other words, the absorber layer is preferably arranged exclusively on the structured spacer layer. Preferably, such (sub) areas arise in which there is no reflection layer, no structured spacer layer and no absorber layer (negative pattern areas), which are arranged next to other (sub) areas in which the reflection layer, the structured spacer layer and the absorber layer are present (thin-film element areas).

The arrangement of the absorber layer is preferably carried out using a donor sheet. Preferably, the donor sheet may be a metal donor sheet. The absorber layer can from the donor sheet z. B. be arranged with a roll-to-roll method on the structured spacer layer or transferred to the structured spacer layer.

Further preferably, the method comprises the further step of "arranging a relief structure with raised and recessed areas in the area of the carrier material to be coated".

If the relief structure is designed, for example, as a sine grid or a crossed sine grid, the raised areas are located where the underlying (normalized) sine function assumes the value 1 or a range of values from 1 to greater than 0. The recessed areas are then, for example, at the value -1 or in the value range from -1 to less than 0.

Preferably, the relief structure is formed as an embossed structure. Preferably, the carrier material may have an embossed structure. Alternatively or additionally, a relief layer, preferably of embossing lacquer, which is provided with a relief structure / embossed structure can be arranged on a main surface of the carrier material at least in the area to be coated. The method may preferably have the following sequence of steps:

a) providing a carrier material with at least one area to be coated / a surface defined as a region to be coated;

b) arranging a relief structure in the area to be coated; c) arranging a reflection layer on the relief structure in the area to be coated.

Alternatively or additionally, a relief structure can be arranged after arranging the reflection layer, so that both the reflection layer and the embossing layer and / or the support material are provided with a relief structure.

Furthermore, alternatively or additionally, a relief structure can be arranged after arranging the structured spacer layer, so that the relief structure is introduced into the structured spacer layer.

Furthermore, alternatively or additionally, a relief structure can be arranged after arranging the absorber layer, so that the absorber layer itself and / or a (protective) layer covering the absorber layer have the relief structure.

Preferably, the method comprises the further step "leveling the relief structure by arranging the structured spacer layer on the reflective layer".

Preferably, the recessed areas of the relief structure are filled with material of the structured spacer layer, so that the material of the structured spacer layer reaches at least the level of the raised areas. Preferably, the material of the patterned spacer layer is a liquid. Preferably, the relief structure is scraped / wiped off after arranging / applying the material of the patterned spacer layer so that the material of the patterned spacer layer does not or only slightly exceeds the level of the raised regions. The term "slightly exceeding" is to be understood in particular to mean a layer thickness / height which exceeds the layer thickness / height up to the level of the raised regions by up to 10%, preferably by up to 5%, of the layer thickness.

Advantageously, removal of / doctoring off or wiping off the relief structure after application of the material of the structured spacer layer removes excess material of the structured spacer layer. Consequently, material of the structured spacer layer can thus be saved in the course of the process / production process.

After being arranged on the relief structure, the structured spacer layer has (lower) regions with a higher layer thickness / height and adjacent (lower) regions with a lower layer thickness / height. Preferably, the region to be coated has subregions / subregions which have a layer thickness of the structured spacer layer of zero or slightly thicker than zero. In other words, the structured spacer layer has a structure that substantially corresponds to a negative of the relief structure.

Further preferably, the method comprises the further step of "removing the reflection layer in the raised areas of the relief structure." The structured spacer layer allows removal of the reflection layer only in the (sub) areas in which the raised areas do not or only slightly through the structured level layer are covered or the level of the structured spacer layer does not or only slightly exceeds the level of the raised areas.

In other words, the reflective layer is removed in the areas in which the reflective layer is not protected by the patterned spacer layer. If the level of the structured spacer layer is higher than that of the raised regions, first the structured spacer layer and then the reflective layer are removed. Advantageously, the reflective layer remains in the recessed areas of the relief structure after completion of the step of "removing the reflective structure in the raised areas of the relief structure" because the patterned spacer layer is not or not completely removed during the process step and therefore the reflective layer in the recessed areas remains protected. Advantageously, the duration of a subsequent step "removing the reflective layer in the raised areas of the relief structure" is kept as short as possible by limiting the layer thickness of the structured spacer layer to a maximum dimension / maximum, since then the desired or fixed removal of the reflective layer in the raised areas of the relief structure is not delayed by a previously necessary removal of the structured spacer layer.

After removal of the reflection layer in the raised areas of the relief structure may possibly be an uneven surface structure. In other words, at least partially, a relief structure may be present again. Therefore, the method preferably includes the further step of leveling the surface structure in the area to be coated

Arranging material of the structured spacer layer; and / or arranging filler.

Preferably, the filler or the filling material has a solids / solids content of 100%.

The structured spacer layer is preferably arranged / applied by printing in the form of a motif.

The structured spacer layer is preferably arranged by means of one or more rollers and / or cylinders. In particular, the number of rolls may vary. Depending on the speed, the rollers / cylinders can transport paint and / or paint to each other. The arrangement of the motif or the motif print is preferably carried out by a high-pressure mold. The structured spacer layer is preferably applied by means of a flexographic printing process. Alternatively or additionally, the structured spacer layer is applied by gravure printing. Alternatively or additionally, the structured spacer layer is applied by means of inkjet printing methods. Alternatively or additionally, the structured spacer layer is applied by means of offset printing. Alternatively or additionally, the structured spacer layer is applied by means of screen printing. Alternatively or additionally, the structured spacer layer is arranged by means of 3D printing methods.

Preferably, the printing unit can be encapsulated or atmospherically sealed to arrange the structured spacer layer, so that there is a solvent-saturated atmosphere in the printing unit area. The solvent-saturated atmosphere advantageously prevents / prevents the printing ink or the dielectric from drying on rollers and / or cylinders.

Advantageously, the desired layer thickness can be achieved very quickly, for example in comparison to application by means of physical vapor deposition, by means of a printing technique arrangement or application of the structured spacer layer In the case of arranging a spacer layer by means of physical vapor deposition, for example, when arranging a spacer layer by means of physical vapor deposition, it is customary to provide a further / downstream process step for structuring such a spacer layer full-surface / uniform or applied unstructured spacer layer, which is then removed, for example by means of an etching process regions, so as to obtain a structured spacer layer.

Preferably, the step "removing the reflective layer ..." comprises etching.

In other words, the reflection layer is removed by means of an etching process or etchant as removal agent. Preferably, caustic soda or phosphoric acid is used as etchant.

Advantageously, the etchant penetrates the absorber layer, so that contact between the etchant and the reflection layer is produced. Advantageously, the reflection layer can thus be dissolved or detached. Advantageously, the fixed bond / connection between the absorber layer and the carrier layer is also released by the detachment of the reflection layer, so that the absorber layer is removed by removing the reflection layer at the same time. In the (sub) regions in which the structured spacer layer is arranged, the etchant can advantageously not strike the reflective layer after penetrating the absorber layer, so that the reflective layer and the absorber layer remain in these regions.

Alternatively or additionally, the step "removing the reflective layer ..." comprises lasers.

In other words, the reflection layer is removed by laser beam treatment as a removing means. Furthermore, preferably, the absorber layer is not detached or impaired by the laser radiation. Advantageously, the laser radiation can penetrate the absorber layer. and remove the reflective layer. Advantageously, the patterned spacer layer sufficiently protects the reflective layer from the laser radiation so that the reflective layer is not removed in the (sub) areas where the patterned spacer layer is disposed.

For example, the laser used may emit infrared laser radiation and the patterned spacer layer may have infrared-blocking properties such that the laser radiation can not penetrate the patterned spacer layer.

Preferably, the method comprises the further step of "arranging an adhesion-promoting layer".

Preferably, the adhesion-promoting layer is arranged (temporally) before the step "arranging the reflection layer ..." In other words, the adhesion-promoting layer is arranged between the support material and the reflection layer Advantageously, the bond between the reflection layer and the reflective layer If an embossing lacquer / an embossing lacquer layer is arranged between the support material and the reflection layer, the adhesion-promoting layer improves the bonding of the support material and the reflection layer The adhesion-promoting layer can comprise metallic and / or non-metallic materials In addition, the method comprises the further step of "applying a protective layer".

Before geous wise, the protective layer after a "arranging the absorber layer ..." or a "removing the reflective layer ..." angeord- net to protect the structures generated by the method. Advantageously, the protective layer is arranged in the (entire) area to be coated. The protective layer preferably comprises a protective lacquer. Alternatively or additionally, the protective layer comprises a heat sealing lacquer and / or a primer.

The structured spacer layer preferably has at least partially deformation properties which lead to deformation-induced color changes of the security element.

As a result, a color change in the deformed portions of the area to be coated as compared to a non-deformed state is recognizable to a viewer after a deformation of the structured spacer layer.

Advantageously, the deformation of the structured spacer layer leads to a color change of the security element or region in the deformed sections, in which the structured spacer layer has the deformation properties which lead to deformation-induced color change properties of the security element. Preferably, such a color change of the security element or the deformation of the structured spacer layer is reversible. Advantageously, the color change remains at least some time after the deformation, so that the color change is also recognizable for a while in a again no longer deformed state for a viewer. Advantageously, after arranging the patterned spacer layer, the deformation-related color change characteristics can be set. The deformation-related color change properties can be determined by thermal crosslinking and / or vulcanization and / or radiation curing.

According to one embodiment, the entire structured spacer layer has deformation properties which lead to deformation-induced color change properties of the security element. According to a further embodiment, only partial regions / sections of the structured spacer layer have deformation properties which lead to deformation-induced color change properties of the region to be coated or the security element. For example, by means of selective irradiation, the subregions / sections of the structured spacer layer which should have deformation properties for a color change can be defined or defined.

By means of a mask, it can preferably be determined which sections of the security element or of the region to be coated should have deformation-induced color change properties. In other words, a mask is used to provide a patterned spacer layer with portions having deformation properties for deformation-related color changes of the security element. The mask preferably protects the sections of the structured spacer layer from irradiation / vulcanization or thermal crosslinking which should or should not have deformation-induced color change properties. Preferably, such a mask is designed as a motif or pattern. Consequently, it is possible that upon (or after deforming) the area to be coated due to the color change in the portions of the area to be coated with deformation-related color change properties, a (further) pattern / motif is recognizable to a viewer.

Preferably, a structured spacer layer, which has deformation properties that lead to color changes of the security element due to color, is at least partially gel-like. Preferably, the structured spacer layer is an elastomer. For example, by bending or folding a security element with an at least partially gel-like or jelly-like structured structured spacer layer, the layer thickness of the gel-like, structured spacer layer can be locally changed, so that this local layer thickness change in the thin-layer element area when viewing the security element Color change / color Change of this thin-film element area.

Alternatively or additionally, deformation properties of the structured spacer layer, which lead to a detectable color change, can be achieved by an at least partially different swelling behavior. For example, for a viewer when moistening the security element, this can make a color change in the sections of the structured spacer layer with a stronger swelling behavior compared to the sections of the structured spacer layer with a lower swelling behavior detectable. Advantageously, the color change remains at least some time after swelling, so that the color change even after moistening - for example, by breathe, which leads to a swelling - is recognizable to a viewer. According to a further embodiment, the entire structured spacer layer has a strong swelling behavior, so that after moistening, a color change due to a swelling-induced increase in layer thickness of the structured spacer layer can be detected when viewing the security element.

The structured spacer layer preferably has direction-dependent refractive indices. In other words, the structured spacer layer is anisotropic

Layer. Depending on the viewing direction, a viewer can advantageously detect a different color tilting effect on the area to be coated or the security element due to the direction-dependent refractive indices. For example, when looking from an oblique direction to the area to be coated and turning / rotating the area to be coated around the main surface normal in the centroid of the area to be coated a (further) color shift effect can be seen. Preferably, this color shift effect is different in color from the other Farbkippef- effects in the area to be coated.

The structured spacer layer preferably has one or more dyes.

Preferably, the structured spacer layer comprises pigments. Preferably, the pigment size or pigment dimensions / diameter does not exceed the layer height or layer thickness of the structured spacer layer.

Preferably, the dyes and / or pigments comprise fluorescence properties. Advantageously, the structured spacer layer has a toning or slight coloring, so that the structured spacer layer at least does not appear to be completely transparent to a viewer.

Advantageously, fluorescing or toning or light staining of the structured spacer layer makes it possible for the structured spacer layer to be visible or made visible to the personnel when the security element is produced. For example, this allows a review of the manufacturing process or the process step "arranging the structured spacer layer" are facilitated.

The structured spacer layer preferably has a dry layer thickness of 30 nm to 1100 nm, preferably of 300 nm to 600 nm. Preferably, for a viewer of the security element having a patterned spacer layer with a dry layer thickness / height of less than 350 nm, a motif formed by the patterned spacer layer can be seen in a (single) color.

At a dry layer thickness of 350 nm of the structured spacer layer, a color shift effect / colorshift effect can be recognized by the viewer. At a dry layer thickness of 30 nm to 80 nm of the structured spacer layer, no color shift effect, but a deep black is discernible.

The security element preferably has at least one relief structure such as a hologram and / or moth eyes and / or microlenses and / or micromirrors. Preferably, the relief structure can be provided with the step "arranging a relief structure with raised and recessed areas in the area of the support material to be coated." Alternatively or additionally, other relief structures may be provided which are in other layers such as the embossed layer, the structured spacer layer , the absorber layer and / or the protective layer are arranged.

Preferably, the carrier material comprises a carrier film. Particularly preferably, the carrier material comprises polyethylene terephthalate (PET) and / or polypropylene (PP), particularly preferably the carrier material is PET or PP.

Preferably, the substrate may be removed prior to applying the security element to a value document substrate. Preferably, the security element comprises at least one adhesive layer or at least one release layer, which is applied between the carrier material and the reflective layer.

Preferably, the reflective layer includes aluminum and / or silver. In particular, the reflective layer is an aluminum layer or a silver layer.

Preferably, the absorber layer includes an etchant permeable material. Preferably, the absorber layer includes a transparent or semi-transparent material for laser radiation. In other words, the absorber layer contains a material which is at least semitransparent for laser radiation. Preferably, the absorber layer includes chromium. In particular, the absorber layer is a chromium layer. Preferably, the patterned spacer layer is a dielectric. Preferably, the dielectric has resist coating properties.

Preferably, the patterned spacer layer is based on vinyl chloride copolymers having acid groups. For example, in the case of vinyl chloride copolymers having acid groups, it may be the product HI 5 / 45M from Wacker Chemie AG, which is marketed under the trademark VINNOL®. According to the manufacturer H 15/45 M is a carboxyl-containing terpolymer of about 84% by weight of vinyl chloride (VC) and ca.

15% by weight of vinyl acetate (VAc) and about 1% by weight of dicarboxylic acid. It is preferably used according to the manufacturer as a binder for paints and printing inks.

Preferably, the structured spacer layer is based on nitrocellulose. As a result, a good course of the structured spacer layer is achieved.

Preferably, the patterned spacer layer is based on acrylate (s). As a result, a high transparency and subsequent deformability by embossing or embossing is possible. Advantageously, the structured spacer layer contains an acrylate leveling additive, such as Byk 361. This can advantageously promote a uniform surface structure of the structured spacer layer, so that the absorber layer can be arranged on such a planar surface structure. Preferably, the patterned spacer layer is based on acrylic acid ester. Preferably, the patterned spacer layer is based on epoxide (s). Preferably, the structured spacer layer is based on polyurethanes). The advantage of epoxides and polyurethane (s) is good crosslinkability, so that a good resistance to overprinting with solvent-based paints is obtained. Preferably, the structured subscription Standing layer also based on combinations of the above substances. Further preferably, the structured spacer layer is based on a water-soluble substance. Preferably, the patterned spacer layer may be based on vinyl chloride copolymer having acid groups (eg, VMCH, which is a product name of a vinyl chloride copolymer having acidic groups and is manufactured by the Dow Chemical Company). For example, a sample formulation could be: 20% vinyl chloride copolymer with acid groups (VMCH), 20% methyl ethyl ketone (MEK), 20% ethyl acetate, 20% toluene, 20% butyl acetate. VMCH has a very good adhesion to metals. The contained solvent mixture is well suited for preventing drying artifacts. Polyvinyl butyral is also suitable. UV reactive coatings can also be used.

According to one exemplary embodiment, if an etchable layer (eg aluminum) is applied as a reflector in the first step, for example, in a second step, a photoresist can even be applied over the entire surface. By exposure, washable / etchable and non-washable / non-etchable areas can be created. This exposure can be done before or after the application of the absorber. If the areas of the resist which have the corresponding sensitivity are removed by washing / etching, the reflection layer can be structured either simultaneously or in a subsequent step with a further etching medium. The absorber layer is, without having to be self-etched, structured in this procedure with. Alternatively or additionally, the structured spacer layer comprises nematic liquid crystals. Advantageously, a structured spacer layer with direction-dependent refractive indices can be provided by means of nematic liquid crystals. Preferably, nematic liquid crystals can be printed as a (structured) spacer layer. Preferably, these nematic liquid crystals are aligned by suitable alignment / alignment techniques, such as embossing, photoaging, shear or compression, or arrangement based on the choice of substrate to be printed. If a spacer layer is provided with such aligned nematic liquid crystals, further optically variable effects are obtained in addition to the color-tilting effect based on the thin-film element. If the nematic liquid crystals form a uniform, generally anisotropic structured spacer layer, then this structured spacer layer has a (different) refractive index which depends on the viewing direction. This causes the color shift effect to vary depending on the viewing direction. For example, results in oblique viewing and horizontal rotation of the security element an additional color change. If the nematic liquid crystals of the structured spacer layer are aligned differently in certain regions, the liquid crystals, which are oriented differently in some areas, give rise to a (separate) motif. This makes it possible to perceive a uniform color when the main surface of the security element is viewed almost perpendicularly, while the tilting of the security element / oblique viewing of the main surface of the security element identifies the (separate) motif due to the differently aligned liquid crystals. Preferably, the patterned spacer layer is not Si0 ₂ .

A further aspect relates to a security element, wherein the security element has been produced by one or more of the previously described method steps and / or under the described aspects. A security element according to this invention may in particular comprise a film or a multilayer substrate, wherein the multilayer substrate may also comprise a combination of fabric substrates and films. For example, the security element may comprise a window area which serves to fill or bridge a hole in a value document or in the paper substrate of the value document. In other words, a security window in a value document can be inserted / applied with the security element. Preferably, the area to be coated is arranged in the window area of the security element. Alternatively, the security element may be applied to a value document, for example laminated or glued. The security element may be a security thread or ribbon, window thread, patch or the like. A further aspect relates to a value document, in particular a banknote, having a value document substrate and at least one security element which has been produced by means of one or more of the previously described method steps and / or under the described aspects. A security element is preferably placed on or in a value document substrate. A value document substrate may comprise paper, polymer or a paper-polymer combination. In the case of a banknote made of polymer or a paper-polymer combination as a value-document substrate, the carrier material of the security element may be a subarea of the value-document substrate. For example, the value document substrate may be a polymer film and the support material of the security element is a portion of this polymer film. If the security element is embedded in a value document, the top side and the bottom side of the security element preferably run (substantially) parallel to the top side and bottom side of the value document substrate. The top and bottom of the value document as well as the security element may also be referred to as major surfaces. These main surfaces represent relevant information to a viewer. Consequently, the main surfaces are visible to a viewer who views a value document with a security element. For example, a major surface of a bill may represent the value of the bill as well as its serial number. Accordingly, an upper and lower side of a security element as well as a value document can also be regarded as the first and second main areas.

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

Show it:

Fig. La, lb is a schematic representation of a value document with a

Safety element;

2a-f is a schematic representation of the manufacturing method of a security element according to a first variant;

3a-e a schematic representation of the manufacturing method of a security element according to a second variant; 4a-g is a schematic representation of the manufacturing method of a security element according to a third variant;

Fig. 5a-5c is a schematic sectional view of security elements with protective layer;

6a, 6b is a schematic representation of a section of a value document with a security element; FIGS. 1 a and 1 b each show a schematic plan view of a main surface of a value document 100 with a value document substrate 102 and a security element 104, wherein the security element 104 is firmly connected to the value document substrate 102, e.g. B. imbedded in the value document substrate 102 or applied to the value document substrate. The security element 104 may also be a subarea of the value document substrate 102.

The security element 104 has a surface defined as the region 106 to be coated, which comprises a negative pattern region 108 and a lens shift or thin-film element region 110.

FIG. 1 a shows the number 45 as negative pattern region 108 a. FIG. 1 b shows three stripes as negative pattern region 108 b. A negative pattern area may further have any shape or configuration. For example, a negative pattern area could be in the shape of a church or an animal. Preferably, a negative pattern area allows a viewer to see the negative pattern area in plan view and / or in review. Preferably, the safety unit in the negative pattern area transparent or at least semitransparent, so that at least a part of the incident on the security element light is transmitted in the negative pattern area. Further preferably, the negative pattern region in supervision may have a different color-related appearance than in transparency (so-called see-through color effects). In other words, the color appearance of the negative pattern area in plan view (eg gold), in which the proportion of the reflected light determines the color appearance, other than in review (eg blue), in which the proportion of transmitted light is the color Appearance determined. The security element 104 comprises a carrier material which preferably consists of polyethylene terephthalate (PET) and has a region 106 to be coated. The thin-film element region 110, which is a subregion or partial region of the region 106 to be coated, comprises at least one reflection layer, a structured spacer layer and at least one absorber layer. The negative pattern region 108 has at least no reflection layer and no structured spacer layer in comparison with the thin-film element region 110.

Accordingly, it can be clearly seen that the structured spacer layer is not present over the entire surface or evenly in the region 106 to be coated, but only / exclusively in the thin-film element region 110.

The structure of a region 108 to be coated with thin-film element region 110 and negative-pattern region 108 will be explained in more detail below with the aid of FIGS. 2 to 5.

Figures 2a to 2f show various (process) steps for producing a security element having a thin-film element region and a negative-pattern region. Fig. 2a shows the sectional view of a region to be coated 202 of a carrier material 200. The area to be coated 202 is disposed on the main surface of the carrier material HF. In order to produce a security element, as shown in a comparable manner in FIGS. 1 a and 1 b, after the process step "providing a carrier material 200 with at least one region to be coated", a reflection layer 204 is introduced into the region 202 to be coated in a subsequent process step 2b shows, in this connection, a reflection layer 204 which was arranged in / on the region 202 to be coated. As can be seen from FIG. 2b, the reflection layer 204 was arranged on the main surface HF of the carrier material 2b, the reflection layer 204 is arranged over the whole area in the region 202 to be coated, In a next step, as shown in Fig. 2c, a structured spacer layer 206 is arranged on the reflection layer 204. Due to the structure of the structured spacer layer 206, FIGS the region 202 to be coated is a thin-film element Area 210, which consists of several sub-areas 210a to 210c, and a negative pattern area 208, which consists of the sub-areas 208a and 208b formed. For example, the structured spacer layer 210 corresponds to the thin-film element region 110a or 110b according to FIGS. 1a and 1b. Thus, the negative pattern area 208 may have a shape like the negative pattern areas 108a or 108b of FIGS. 1a and 1b. In other words, it is determined by the structure of the patterned spacer layer which regions or subregions of the region 202 to be coated are formed as thin-film element regions 210 and negative-pattern regions 208, respectively. Advantageously, the patterned spacer layer 206 is a dielectric. Furthermore advantageously, the structured spacer layer 206 can be arranged on the reflection layer 204 by means of one or more rollers or printing methods. This is particularly advantageous since in this way a very wide variety of structures or motifs which the structured spacer layer 206 is intended to have can be produced in a simple manner.

In a further method step, as shown in FIG. 2 d, an absorber layer 212 is arranged in the region 202 to be coated. As can be seen from FIG. 2d, the absorber layer 212 is arranged over its entire area in the region 202 to be coated. In a next method step, as shown in FIG. 2e, the reflection layer 204 is removed in the regions in which the reflection layer 204 is not protected by the structured spacer layer 210. In other words, the structured spacer layer 206 serves as a mask or protective layer, thereby enabling a selective removal of the reflective layer 204. For example, the removal of the reflection layer, as shown in FIG. 2e, can be achieved by means of homogeneous irradiation or use of an etchant 214. Advantageously, the absorber layer 212 is removed by removing the reflection layer 204 at the same time. This results in a security element having a region 202 to be coated, as shown in FIG. 2f. In particular, only the thin-film element region 210 or the thin-film element subregions 210a, 210b, 210c has a reflection layer 204. In other words, by removing the reflective layer 204 in the areas 208a, 208b in which the removal of the reflective layer 204 is not prevented by the protection of the patterned spacer layer 206, a patterned reflective layer and a patterned absorber layer are formed. This structured reflection layer as well as these The structured absorber layer preferably has the same structure / structuring as the structured spacer layer 206.

In particular, the sectional representation of a region 202 to be coated shown in FIG. 2f may correspond to a section along the line I-I according to FIG. 1a or the line II-II according to FIG. 1b.

Figures 3a to 3e show the various process steps for producing a security element according to another variant. FIG. 3 a shows the provision of a carrier material 300 with a main surface HF and a region 302 to be coated in a sectional view. This sectional view may, for example, correspond to a sectional view along the line I-I as shown in FIG. 1a or along the section line II-II according to FIG. 1b. 3b shows the method step "arranging a reflection layer 304" in the region 302 to be coated. As already shown in FIG. 2b, the reflection layer 304 is also arranged uniformly or unstructured on the main surface HF in the region 302 to be coated In a subsequent method step, the structured spacer layer 306 is arranged on the reflection layer 304. Due to the structure of the structured spacer layer 306, regions or subregions 310a-310c which have a structured spacer layer 306 result in the region 302 to be coated. Subregions 308a, 308b in the region 302 to be coated which do not have a patterned spacer layer 306.

The structured spacer layer 306 is adapted to protect the reflective layer 304 from being removed. In a next method step, the reflection layer 304 in the areas 308a, 308b is removed. In other words, the structured spacer layer 306 serves as a mask or enables selectively removing the reflective layer 304. The removal may advantageously be done because of the function of the patterned spacer layer 306 as a mask by means of homogeneously applied removal means, such as radiation or etchant. A substantially homogeneous action of a removal agent or an irradiation or an etchant 314 is shown schematically in FIG. 3d. In a subsequent method step, an absorber layer 312 is arranged in the region 310 or the sub-layers 310a, 310b, 310c. As a result, a negative pattern region 308 or negative pattern regions 308a, 308b results, in which no reflection layer 304 and no absorber layer 312 are arranged. In other words, the absorber layer 312 is selectively patterned according to the structure of the patterned spacer layer 306. In other words, a structured absorber layer 312 is formed.

Preferably, the manufacturing processes as set forth with reference to FIGS. 2 and 3 may comprise further or additional process steps. In particular, such further or additional method steps can also be carried out between one or more of the explained method steps. For example, it is possible to arrange a relief structure as an additional method step, wherein this method step is performed before arranging the reflection layer 204 or 304. A further variant for producing a security element will now be explained with reference to FIGS. 4a to 4f. 4a shows the sectional view of a carrier material 400 with a main surface HF and a region 402 to be coated. The carrier material 400 with the region 402 to be coated is produced as part of a method step as shown in FIG. 4a. provided. In a further method step, a relief structure 404 with raised regions 408 and recessed regions 406 is arranged in the region 402 of the carrier material 400 to be coated. According to one embodiment, the relief structure may be formed by embossing the backing material as 400. According to another exemplary embodiment, the relief structure 404 can be arranged or shaped in that a relief / embossing layer, such as an embossing lacquer, is applied or arranged on the main surface HF of the carrier material and this embossing layer is given a relief structure 404 by means of an embossing tool. In particular, a relief structure 404 can be arranged or formed by a relief structure 404 is introduced into a relief layer, for example by means of etching or lasers. With a further method step, a reflection layer 410 is arranged in the region 402 to be coated. This may be done, for example, by sputtering, so that material of the reflective layer 410 is deposited in the raised areas 408a-d and in the recessed areas 406a-e. In this regard, reference is made to Fig. 4c. In a further method step, as shown in FIG. 4d, a structured spacer layer 412 can be arranged. In this case, the structured spacer layer is arranged on the reflection layer 410 at least in the recessed areas 406a-e. In other words, the relief structure 404 is planarized by arranging the patterned spacer layer 412 on the reflective layer 410.

Preferably, material of the structured spacer layer 412 is not or only slightly present on the reflective layer 410 in the raised regions 408a-d. This can be achieved, for example, by performing a doctoring or wiping off of excess material of the structured spacer layer 412. The structured spacer layer 412 forms a mask so that the reflective layer in the recessed areas 406 is protected from being removed during the process step "removing the reflective layer 410 in the raised areas 408 of the relief structure 404." or thin material layer of the structured spacer layer 412 also on the reflection layer 410 in the raised areas 408, then, in the course of the process step "removing the reflection layer in the raised areas of the relief structure", material of the structured spacer layer 412 is removed first and then the reflections on layer 410 in the raised areas 408. The reflective layer 410 in the recessed areas 406 remains protected by the (remaining) patterned spacer layer 412 since the step "removing the reflective layer in the raised areas" is terminated after the reflection scan 410 was removed in the raised areas 408. This is shown, for example, with reference to FIG. 4e, wherein the reflection layer 410 has been removed in the raised regions 408 by means of uniform or homogeneous action of radiation or an etchant 414. Possibly, after removing the reflective layer 412 in the raised regions 408a-d, the situation may arise that the spacer layer in the regions 406 has been partially removed, resulting in a surface structure in the region 402 to be coated, as shown in FIG. 4f. In a further process step, this surface structure can be smoothed again by leveling. For example, by means of filling with or arranging material of the structured spacer layer or of another material or filler, the leveling can take place. This process step may preferably also include a removal or scraping of superfluous or excess material. In a next method step, an absorber layer 416 is arranged at least on the structured spacer layer 412. As shown in FIG. 4g, the absorber layer 416 can also be arranged in the entire area 402 to be coated.

FIGS. 5a to 5c each show a schematic sectional view of a security element with a protective layer 514a, 514b or 514c. The

Protective layer is preferably used to protect the absorber layer or the area to be coated from external influences. The protective layer 514a, 514b or 514c is preferably transparent. As shown in FIG. 5 a, the protective layer or the protective lacquer that is present in the area to be coated 502 a can planarize. Advantageously, the flanks of thin-film element regions 510a are thereby also prevented from external influences, such as e.g. during the circulation of a banknote, protected. As shown in FIG. 5b, the protective layer 514b may be applied as a thin film so that there is no leveling of the structures in the area 502b to be coated. Advantageously, the absorber layer 512b can be protected from external influences by the protective layer 514b. In FIG. 5c, a uniformly distributed or homogeneously applied protective layer 514c covers the absorber layer 512 in the region 502c to be coated.

FIG. 6 a shows a section of a value document 600 with a value document substrate 602 and a security element 604, which is embodied for example as a patch. The security element 604 comprises a region 606 to be coated, which comprises a thin-film element region 610 and a negative-pattern region 608. The thin-film element region 610 has (area-wise) deformation-induced color change properties. The deformation-related color change properties are preferably produced by deformation properties of the structured spacer layer that is present in the thin-film element region 610. aims. In particular, the deformation-related color change properties are achieved by deforming the structured spacer layer by external action, such as moisture penetration by breathing, irradiation or buckling of the security element, so that the thickness of the spacer layer is reduced or increased locally. FIG. 6 a shows a thin-film element region 610 which has a structured spacer layer which has deformation properties in partial regions or sub-regions. In FIG. 6a, these subregions with deformation properties are not recognizable to a viewer because the patterned spacer layer is in a non-deformed state. If now the security element 604 or the thin-layer element region 610 is deformed, namely by deforming the structured spacer layer, the subarea or subarea of the structured spacer layer with deformation properties that lead to a deformation-related color change becomes recognizable for a viewer. In Fig. 6b, the state is shown by the viewer for the deformation-related color change - after deformation of the structured spacer layer - can be seen. Referring to Fig. 6b, the sub-region 612 having the deformation characteristics resulting in a deformation-induced color change represents the character "A". Preferably, these deformation-related color changes are reversible, such that some time after deformation, the sub-region 612 becomes observer fades or is no longer recognizable, and thus again a state according to Figure 6a is present. LIST OF REFERENCE NUMBERS

100, 600 value document

102, 602 value document substrate

104, 604 security element

106, 202, 302, 402, 502, 606 area to be coated

108, 208, 308, 408, 508, 608 negative pattern area

110, 210, 310, 410, 510, 610 thin-film element area

200, 300, 400, 500 carrier material

204, 304, 410 reflection layer

206, 306, 412 structured spacer layer

212, 312, 416, 512 absorber layer

214, 314, 414 removal means

404 relief structure

514 protective layer

612 Subrange with deformation-related

Color changing properties

HF main area

Claims

Patent claims

A method of making a security element (100, 600) comprising the steps of:

- Providing a substrate (200, 300, 400, 500) with at least one area to be coated (106, 202, 302, 402, 502, 606);

Arranging a reflection layer (204, 304, 410) in the area to be coated;

Arranging a patterned spacer layer (206, 306, 412) on the reflective layer, wherein the patterned spacer layer is adapted to protect the reflective layer from being removed;

Arranging an absorber layer (212, 312, 416, 512) at least on the patterned spacer layer; and

Removing the reflection layer in the areas in which the removal of the reflection layer is not prevented by the protection of the structured spacer layer.

2. The method of claim 1, wherein the step of disposing an absorber layer is performed prior to the step of removing the reflective layer.

3. The method of claim 1, wherein the step of removing the reflective layer is performed before the step of disposing the absorber layer, and preferably arranging the absorber layer using a donor sheet.

4. The method according to any one of claims 1 to 3, comprising the further step:

Arranging a relief structure (404) with raised and recessed areas (408; 406) in the region of the carrier material to be coated.

5. The method according to claim 4, comprising the further steps:

Flattening the relief structure (404) by arranging the patterned spacer layer on the reflective layer; and

Removing the reflective layer in the raised areas (408) of the relief structure.

6. The method according to any one of claims 1 to 5, wherein the structured spacer layer and / or the reflective layer and / or the absorber layer by printing in the form of a motif, preferably by means of

Flexographic, gravure, inkjet, offset, screen printing or 3D printing is arranged.

7. The method of claim 1, wherein the step of removing the reflective layer comprises etching and / or lasers (214, 314, 414).

8. The method according to any one of claims 1 to 7, comprising the further step:

Arranging an adhesion-promoting layer; and or

- Applying a protective layer.

9. The method according to any one of claims 1 to 8, wherein the structured spacer layer has at least partially deformation properties that lead to deformation-related color changes of the security element ren (612).

10. The method according to any one of claims 1 to 9, wherein the patterned spacer layer has directional refractive indices and / or dyes and / or pigments.

11. The method according to any one of claims 1 to 10, wherein the structured spacer layer has a dry film thickness of 30nm to llOOnm, preferably 300nm to 600nm.

12. The method according to any one of claims 1 to 11, wherein the security element has at least one relief structure such as a hologram, moth eyes, microlenses or micromirrors.

13. The method according to any one of claims 1 to 12, wherein the carrier material comprises a carrier film, preferably of polyethylene terephthalate (PET); and or

the reflective layer includes aluminum; and or

the absorber layer preferably comprises an etchant permeable material, preferably chromium; and or

the absorber layer includes a material which is at least semitransparent for laser radiation; and or

the patterned spacer layer is a dielectric and is preferably based on vinyl chloride copolymers with acid groups, nitrocellulose, acrylate (s), acrylic ester, epoxide (s) or polyurethane (s); and / or the structured spacer layer comprises nematic liquid crystals.

14. Security element, wherein the security element has been produced by the method according to one of claims 1 to 13.

15. document of value, in particular banknote, with a value document substrate and at least one security element according to claim 14.