Process for manufacturing a flake pigment

Abstract

The invention relates to a method for manufacturing a sheet-like pigment, comprising the steps: - providing a foil structure comprising a carrier substrate, a water-soluble release layer and a pigment material layer; - mechanically breaking the pigment material layer present in the foil structure at defined locations; - impregnating the foil structure with an aqueous solution; - applying a mechanical force to the foil structure such that the pigment material layer is detached from the carrier substrate as a plurality of pigments corresponding to the cracks present at the defined locations.

Description

Technical Field

[0001] This invention relates to a method for manufacturing flake pigments. Background Technology

[0002] Data carriers, such as valuable documents or certificates, and other valuable items, such as branded goods, are often equipped with effect pigments or protective coatings to achieve protection. These effect pigments verify the authenticity of the data carrier and simultaneously serve as protection against prohibited counterfeits. The effect pigments can be integrated into the substrate of the data carrier or applied to the substrate.

[0003] Pigments, such as effect pigments, can also be manufactured using a thin-layer system that coats a carrier material, such as a carrier foil, with optically variable effects. The coating is then detached from the carrier material and ground into small fragments (see, for example, WO 2019 / 057321A1). These fragments can be dispersed as pigments in an adhesive and ultimately used for printing. Controlled detachment of the coating from the flexible carrier material is achieved, for example, by a special release coating or release layer that reduces the adhesion of the coating to be detached to the carrier material on which the release layer is disposed. Detachment can be achieved, for example, by mechanical stress on the layer structure to be detached, such as by friction, brushing, scraping, or guiding the carrier material onto a deflector roller with a small diameter. The optically variable thin-layer system thus detaches from the flexible carrier material, while the release layer remains on the carrier material.

[0004] However, known manufacturing methods in the prior art are associated with the drawbacks of mechanical stress in sensitive, optically variable thin-film systems, which can lead to damage and consequently reduce the optical effects obtained. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a method for manufacturing pigments that is superior to existing technologies. This is achieved by manufacturing in a way that avoids damage to the thin-layer system. The technical problem is solved according to the following technical solution of the present invention.

[0006] 1. (First aspect of the invention) A method for manufacturing flake pigments, comprising the following steps:

[0007] a) Provide a foil structure comprising a carrier substrate, a water-soluble release layer, and a pigment material layer;

[0008] b) The pigment material layer in the foil structure fractures mechanically at a specific location;

[0009] c) Impregnating the foil structure with an aqueous solution;

[0010] d) Apply mechanical force to the foil structure so that the pigment material layer and the cracks present at a defined location detach from the carrier substrate as multiple pigments.

[0011] 2. (Preferred design scheme) According to the method in paragraph 1, wherein the pigment material layer is a thin-layer system with optically variable effects.

[0012] 3. (Preferred design) The method according to paragraph 1 or 2, wherein the aqueous solution in step c) contains at least 90% by weight water, more preferably at least 95% by weight water, particularly preferably at least 99% by weight water, wherein the remainder particularly comprises wetting agents and / or organic solvents.

[0013] 4. (Preferred design) The method according to one of paragraphs 1 to 3, wherein the mechanical breakage in step b) is achieved by a pressing tool, particularly by a pressing tool having a grid roller, a gravure cylinder or a nickel cylinder.

[0014] 5. (Preferred design scheme) According to one of paragraphs 1 to 4, the mechanical fracture in step b) is achieved as follows, that is, the foil structure deflects under tensile stress on the edge fracture device, that is, on the elongated structure arranged perpendicular to the direction of travel of the foil structure, wherein the elongated structure preferably has a circular, triangular or quadrangular cross section.

[0015] 6. (Preferred Design Scheme) Following the method of paragraph 4 cited in paragraph 5, the mechanical fracture in step b) is achieved by a pressing tool as a pre-structural measure and the following supplementary measures, namely, the foil structure is deflected on the edge fracture device, i.e., the elongated structure arranged perpendicular to the direction of travel of the foil structure, under tensile stress.

[0016] 7. (Preferred design) The method according to any one of paragraphs 1 to 6, wherein in step c), the foil structure is impregnated with an aqueous solution in a wet chamber by spraying with a sprayer, wherein preferably, an elongated, tortuous transport path for the foil structure, implemented by deflection rollers, is provided in the wet chamber.

[0017] 8. (Preferred design) The method according to any one of paragraphs 1 to 7, wherein in step d), mechanical force is applied to the foil structure by means of ultrasonic waves and / or by means of a brush and / or by means of a felt plate or by means of a felt-covered roller and / or by means of a high-pressure nozzle, and preferably by means of a high-pressure nozzle.

[0018] 9. (Preferred design) The method according to any one of paragraphs 1 to 8, wherein the water-soluble release layer is based on a material selected from the group consisting of: polyvinylpyrrolidone, modified starch, polyacrylic acid, polyethylene glycol, hydroxypropyl cellulose, hydroxyethyl cellulose, casein, gum arabic, carboxymethyl cellulose, polyvinyl alcohol, dextrin, or a mixture of two or more of the above materials.

[0019] 10. (Preferred Design Scheme) According to one of paragraphs 1 to 9, wherein the water-soluble release layer has a concentration of 0.05 to 20 g / m³. 2 Preferably 0.1 to 10 g / m 2 A preferred concentration is 0.2 to 5 g / m³. 2 The coating weight within the range.

[0020] 11. (Preferred design) The method according to any one of paragraphs 1 to 10, wherein the water-soluble release layer has a layer thickness in the range of 0.05 to 20 µm, preferably 0.1 to 10 µm, and particularly preferably 0.2 to 5 µm.

[0021] 12. (Preferred design) According to one of paragraphs 1 to 11, wherein the pigment material layer is a thin-layer system with optically variable effects, i.e., a tilt-color-changing thin-layer element that gives the observer different color impressions at different viewing angles, and has an additional magnet layer present when necessary for the magnetic orientation of the pigment.

[0022] 13. (Preferred Design) According to the method in paragraph 12, the tilt-color-changing thin-layer element has a reflective layer, a dielectric spacer layer and an absorption layer, and is preferably formed in a symmetrical multilayer arrangement, wherein the symmetrical multilayer arrangement has the following layer sequence, wherein an additional magnet layer may be included if necessary: ​​absorption layer - dielectric spacer layer - reflective layer - dielectric spacer layer - absorption layer.

[0023] 14. (Preferred Design Scheme) According to the method in paragraph 13, the tilt-colored thin-layer element is formed in a symmetrical multilayer arrangement, wherein the symmetrical multilayer arrangement has the following sequence: Cr / SiO2 / Al / SiO2 / Cr or Al / SiO2 / Al / SiO2 / Al or Cr / SiO2 / Al / FeSi / Al / SiO2 / Cr.

[0024] Detailed description of preferred embodiments

[0025] The method for manufacturing pigments according to the present invention includes the following steps:

[0026] - Provides a foil structure comprising a carrier substrate, a water-soluble release layer, and a pigment material layer;

[0027] - The pigment material layer present in the foil structure fractures mechanically at a specific location;

[0028] - The foil structure is impregnated with an aqueous solution;

[0029] - Apply mechanical force to the foil structure so that the pigment material layer detaches from the carrier substrate as multiple pigments corresponding to the cracks present at certain locations.

[0030] The pigments are particularly selected as effect pigments.

[0031] The carrier substrate is, in particular, a carrier foil, and preferably exists in the form of a continuous foil. Suitable carrier foils include, for example, polyethylene terephthalate (PET), polyethylene (PE), polymethyl methacrylate (PMMA), or polycarbonate (PC).

[0032] In the prior art, so-called dry peeling is known, in which the entire layer structure is mechanically pressured, for example by friction, brushing, or scraping, and the pigment material layer (also referred to herein as the useful coating), especially thin-layer systems with optically variable effects, is then detached from the carrier substrate, while the release coating or release layer remains on the carrier substrate. The mechanical force applied here results in damage to the useful coating, carrier material, or tooling. In contrast, the manufacturing method according to the invention is characterized by the absence of undesirable damage to the useful coating, carrier material, or tooling. Furthermore, the manufacturing method according to the invention is characterized by the absence of risks associated with organic solvents, particularly the danger of fire or explosion and toxicity, due to the use of water. Therefore, no safety precautions are required during the detachment of the useful coating and during continued processing, such as separating the solvent and the useful coating. Compared to the use of organic solvents, the water-based manufacturing method according to the invention offers lower costs, which involves the procurement, processing, and preparation of solvents and exposed materials.

[0033] The term “stripping” as used herein is understood to mean the separation of the pigment material layer from the carrier substrate.

[0034] According to a preferred embodiment, the manufacturing method according to the present invention is implemented in the form of a roll-to-roll process, wherein the foil structure (hereinafter also simply referred to as foil) is as follows: Figure 6 As shown, the material is guided through the stripping device during a series of processing steps. These continuous processing steps specifically include the following steps:

[0035] - Unfold the foil;

[0036] - Mechanically fracture the useful coating;

[0037] - Impregnate the foil with an aqueous solution;

[0038] - Applying mechanical loads to the foil, especially mechanical forces;

[0039] - Collect and extract the aqueous solution containing the pigment;

[0040] - Final cleaning of the foil;

[0041] - Wrap or roll up the foil.

[0042] After the foil is unwound or uncoiled, the pigment material layer or useful coating (especially thin-layer systems with optically variable effects) is broken by mechanical force, thereby allowing water to enter the release layer and facilitating the removal of the useful coating. This can be achieved, for example, by a pressing tool with grid rollers, gravure cylinders, nickel cylinders, or similar structured rollers, and, if necessary, a back pressure roller. The structured rollers can be microscopically structured such that the useful coating, especially the metallized structure, can be randomly loaded or loaded with a well-defined shape and size to produce well-defined pigment particles. Thus, the structured rollers have structures with lateral dimensions ranging from a few micrometers to hundreds of micrometers. Water or a water-surfactant solution is printed in the pressing tool to aid in the dissolution of the separation coating or release layer. Alternatively or additionally, the foil can be subjected to tension in so-called edge breakers, especially elongated structures with very small radii of curvature or edges in their cross-sectional geometry (see, for example, see...). Figure 3 and Figure 4 The edge fracturer causes random breakage of the useful coating to accelerate water ingress. Water lubrication is suitable to prevent damage to the carrier substrate or carrier foil by the edge fracturer. Another feasible method for mechanically loading and breaking the useful coating on the foil is, for example, using a stretching assembly to mechanically stretch the foil. The elastic carrier foil is thus stretched by a few percentage points, and the metallized, glassy layer on the carrier foil breaks. Alternatively, ultrasonic waves can be used to break the useful coating. For this purpose, the foil travels through a basin filled with water, in which one or more ultrasonic probes are present.

[0043] Following mechanical application, the foil is preferably sprayed in a wet chamber using a sprayer to achieve a thin water film (i.e., a wetting film) on the useful coating. To ensure sufficient time for dissolving the release layer or separating the coating, a long, tortuous track path is preferably provided via deflecting rollers in the wet chamber. The sprayer offers the advantage of saving a considerable amount of water. Furthermore, misting is more advantageous than direct water application, such as in a soaking bath, because the water mist is more easily introduced into cracks, especially when the water is heated. Additionally, wetting agents such as isopropanol or suitable surfactants can promote wetting. This process enables higher machine speeds and saves a significant amount of water. Another disadvantage of using a water basin is the accumulation of washed-off pigment in the basin.

[0044] The useful coating, especially the metallized structure, is then removed from the foil by mechanical force. This can be achieved by using ultrasonic strips, brushes, by using a felt bed, by using felt-covered rollers, and / or preferably by using a high-pressure nozzle.

[0045] In the next optional step, the foil undergoes final cleaning, which separates it from the remaining wet area. Advantageously, water jets are sprayed onto both sides of the foil to remove pigments redeposited on the foil during the peeling process through high-pressure nozzles. Optional final drying is then performed by pressing tools and / or by thermal drying, such as by hot air, infrared radiators, heated rollers, or microwaves. The foil is then wound and can be processed or reused.

[0046] The detached pigment preferably accumulates in a slightly inclined trough during the peeling process. The pigment is advantageously collected at the lowest point in the trough by water flow and then pumped for further processing. To conserve process water, water can be drawn from the circulation system, thus requiring little or no fresh water. To prevent the release layer or separation coating from becoming enriched in the process water, it is advantageous that only a certain proportion of the water is circulated.

[0047] The water-soluble release layer is preferably based on a material selected from the group consisting of: polyvinylpyrrolidone, modified starch, polyacrylic acid, polyethylene glycol, hydroxypropyl cellulose, hydroxyethyl cellulose, casein, gum arabic, carboxymethyl cellulose, polyvinyl alcohol, dextrin, or a mixture of two or more of the above materials.

[0048] The application of a water-soluble release layer to a carrier substrate can be achieved, for example, by dissolving the water-soluble material in water or an organic solvent, such as alcohol, ethyl acetate, methyl ethyl ketone, or mixtures thereof, followed by drying. The solution preferably has a solids content in the range of 5 to 70 percent by weight.

[0049] Furthermore, it is advantageous to introduce additional free radical scavengers or polymerization inhibitors into the water-soluble release layer. During the subsequent application of a thin-layer system with optically variable effects via vapor deposition, in addition to the high temperatures generated, ultraviolet radiation, X-rays, and electron beams are produced, during which metals or even other materials such as silica are deposited. Due to this intense radiation, the materials used in the water-soluble release layer may crosslink, thereby reducing the solubility of the release layer. It has been found that adding a certain amount of polymerization inhibitors or antioxidants to the formulation of the water-soluble release layer can advantageously suppress adhesion of the release layer during thermal vapor deposition. For this purpose, it is advantageous to include polymerization inhibitors in the water-soluble release layer at a weight percentage of 0.1 to 10%. To achieve particularly favorable results, the inhibitors used to suppress polymerization are preferably selected from the group consisting of phenol derivatives, especially di-tert-butylmethylphenol or butylhydroxytoluene (BHT), butylated hydroxyanisole (BHA), 4-methoxyphenol (MEHQ), tert-butylmethoxyphenol or thioether-functionalized phenol derivatives, aromatic amines, alkylated phenyl-α-naphthylamine, octylated diphenylamine, butylated diphenylamine, tris(di-tert-butylphenyl)phosphite, 4-hydroxy-2,2,6,6-tetramethyl 4-Hydroxy-TEMPO, tocopherol, especially tocopheryl acetate, β-carotene, ubiquinone-10, glutathione, cysteine, thiolactic acid, melatonin, gallate, especially ethyl gallate, propyl gallate, octyl gallate or dodecyl gallate, ascorbic acid, ascorbyl palmitate, ascorbyl stearate, citric acid, carotenoids, polyphenolic compounds, especially flavonoids, anthocyanins or phytoestrogens, or mixtures of two or more of the aforementioned materials.

[0050] Water-soluble release layers can be applied to a carrier substrate using printing techniques, such as gravure or letterpress printing. The coating weight of the water-soluble release layer is preferably between 0.05 and 20 g / m². 2 Within the range of 0.2 to 5 g / m³, it is particularly preferred. 2 Within the range.

[0051] The preferred thickness of the water-soluble release layer formed on the carrier substrate is in the range of 0.05 to 20 µm, and particularly preferably in the range of 0.1 to 10 µm.

[0052] Pigment material layers arranged on a water-soluble release layer, especially thin-layer systems with optically variable effects, and particularly tilt-sensitive thin-layer elements, give viewers different color impressions at different viewing angles. This thin-layer system can be produced, for example, by PVD or CVD methods. The tilt-sensitive thin-layer element is based on, for example, an absorbing layer (such as Cr) and a reflecting layer (such as Al), wherein the two layers are spaced apart by a dielectric spacer layer (such as SiO2, MgF2, or ZnS) disposed therebetween. Furthermore, thin-layer systems with optically variable effects can particularly have symmetrical structures, for example, with a layer sequence Cr / SiO2 / Al / SiO2 / Cr or a layer sequence of Al / SiO2 / Al / SiO2 / Al. Due to the symmetrical layer structure, the effect pigment produced after pulverizing the thin-layer system has the same optical effect when viewed from both the front and back sides, and is therefore particularly advantageous.

[0053] To separate the obtained pigment from the process water, one or more of the following drying techniques can be used: filtration, decantation, centrifugation, and heating.

[0054] Advantageously, water-soluble release layers and / or thin-layer systems with optically variable effects are equipped with additives that positively influence the properties of the resulting pigments, such as improving corrosion resistance or modifying surface properties for further process steps. Suitable for this purpose are: self-assembled monolayers, especially phosphate, phosphoric acid, phosphate esters, silanes, sol-gel, or silicate coatings; stabilizers; and pH adjusters. Attached Figure Description

[0055] The invention will now be further described with reference to the accompanying drawings. In the drawings:

[0056] Figure 1 The foil structure is shown, which includes a layer system applied to a carrier substrate via a release layer, thereby enabling the generation of pigments;

[0057] Figure 2 The foil structure is shown after measures are taken to mechanically break the thin-layer system present in the foil structure at a defined location;

[0058] Figure 3 An example of mechanical fracture is shown, in which the foil structure is guided on the edge fracturer under tensile stress;

[0059] Figure 4 Another example of mechanical fracture is shown, in which the foil structure is guided on the edge fracturer under tensile stress;

[0060] Figure 5 Four pigments obtained by the method according to the invention are shown;

[0061] Figure 6An example of an implementation of a manufacturing method in the form of a roll-to-roll process according to the invention is shown, wherein the foil structure or foil guide passes through a stripping device during successive processing steps. Detailed Implementation

[0062] Figure 1 The foil structure 4 is shown, which includes a layer system 3 applied to a carrier substrate 1 via a release layer 2, thereby enabling the generation of pigment 8. PET foil serves as the carrier substrate 1, existing in the form of a continuous foil. The carrier substrate 1 has a water-soluble release layer 2. Above the water-soluble release layer 2 is a pigment material layer 3, i.e., a thin layer system with optically variable effects, in this example a layer system having a Cr / SiO2 / Al / SiO2 / Cr layer sequence.

[0063] Figure 1 The foil structure 4 shown is in the form of a roll or continuous foil, which is unwound under stress and then broken by mechanical force so that water can enter the release layer 2. Figure 2 The foil structure 4 is shown after the measure of mechanically breaking the thin layer system 3 existing in the foil structure at a defined location 5.

[0064] For example, breaking can be achieved using a pressing tool with mesh rollers. Alternatively or additionally, a mechanical load can be applied to the thin-layer system 3 by placing the foil structure 4 under tension at the edge breaker (see...). Figure 3 Figure 6 and Figure 4 The attached figure (7) indicates guidance or deflection.

[0065] exist Figure 3 In this case, the edge fracture device 6 is a structure with rectangular edges. The square arrows indicate the direction of travel of the foil structure 4. The edge fracture device 6 causes the thin-layer system 3 to fracture randomly at a defined location 5.

[0066] exist Figure 4 In this case, the edge fracture device 7 is a structure with a triangular cross-section. The square arrow indicates the direction of travel of the foil structure 4. The edge fracture device 7 causes the thin-layer system 3 to fracture randomly at a defined location 5 due to its sharp edge. The crack or fracture portion 5 is not necessarily as... Figure 4 The cracks or fractures shown are not uniformly spaced, but they can also exist at different, randomly distributed distances.

[0067] According to another embodiment not shown in the figure, the edge fracturer has a circular cross-section with a very small radius of curvature.

[0068] The edge breaker shown in the diagram is a schematic simplification. In reality, the edges are rounded.

[0069] Another feasible approach to mechanically load the foil structure 4 and create fractures 5 in the thin-layer system 3 is, for example, to use a stretching assembly to mechanically stretch the foil 4. The elastic carrier substrate 1 is thus stretched by a few percentage points, and the thin-layer system 3 located on the carrier substrate fractures. Alternatively, ultrasonic fracture of the thin-layer system 3 can be used.

[0070] Figure 6 An example of an implementation of a manufacturing method in the form of a roll-to-roll process according to the invention is shown, wherein the foil structure or foil 4 is guided through a stripping device during successive processing steps. The foil structure 4 in continuous foil form begins to be unwound on an uncoiler 9 and is subjected to tensile stress by successive rollers. In a pressing tool 10, which optionally includes structured grid rollers and back pressure rollers, the thin layer system 3 can be broken at a defined location 5 (see...). Figure 2 Alternatively, or additionally, the thin-layer system 3 can also be fractured using the edge fracture device 11. According to... Figure 6 In the example shown, the edge fracture device 11 is arranged in the wet module. Besides the edge fracture device 11, the wet module (in...) Figure 6 (Drawn as a rectangle with solid lines) includes an impregnation zone 12 (indicated by dashed lines), in which the foil structure 4 is impregnated with an aqueous solution. The wet module includes a cleaning zone 13 (indicated by dashed lines), in which the foil is cleaned with a brush 14. In the impregnation zone 12, the foil is sprayed with a sprayer to create a thin water film as a wetting film above the thin-layer system 3. To ensure sufficient contact time for the dissolution of the release layer 2, a long, tortuous track path is set by deflecting rollers. The thin-layer system 3 is then removed from the carrier substrate 1 in the cleaning zone 13 to obtain a single effect pigment 8 (see...). Figure 5 ).according to Figure 6 In the example shown, cleaning is achieved using brush 14. Figure 6 The slightly inclined bottom trough for collecting pigment 8 is not shown. Figure 6 Final cleaning and drying, as well as rolling up the foil, may optionally be performed in further steps not shown in the figure.

Claims

1. A method for manufacturing flake pigments, comprising the following steps: a) Provide a foil structure comprising a carrier substrate, a water-soluble release layer, and a pigment material layer; b) The pigment material layer in the foil structure is mechanically fractured at multiple defined locations to form multiple cracks, the multiple defined locations being in the surface extension region of the pigment material layer, the mechanical fracture being achieved by a pressing tool having a grid roller, a gravure cylinder or a nickel cylinder, or by the foil structure being deflected under tensile stress on an edge fracturer, i.e., an elongated structure arranged perpendicular to the travel direction of the foil structure. c) Impregnate the foil structure with an aqueous solution so that the aqueous solution can be introduced into the water-soluble release layer through the crack and act on the water-soluble release layer; d) Apply mechanical force to the foil structure so that the pigment material layer and the cracks present at multiple defined locations detach from the carrier substrate as multiple pigments.

2. The method according to claim 1, wherein, The pigment material layer is a thin-layer system with optically variable effects.

3. The method according to claim 1, wherein, The aqueous solution in step c) contains at least 90 percent by weight of water.

4. The method according to claim 1, wherein, The aqueous solution in step c) contains at least 95% by weight water.

5. The method according to claim 1, wherein, The aqueous solution in step c) contains at least 99 percent by weight of water.

6. The method according to any one of claims 3 to 5, wherein, The remaining portion includes wetting agents and / or organic solvents.

7. The method according to claim 1, wherein, The elongated structure has a circular, triangular, or quadrangular cross-section.

8. The method according to claim 1, wherein, The mechanical fracture in step b) is achieved by pressing tools as a pre-structuring measure and, supplementarily, by deflection of the foil structure under tensile stress on the edge fracture device, i.e., a long strip structure arranged perpendicular to the direction of travel of the foil structure.

9. The method according to claim 1, wherein, In step c), the foil structure is impregnated with an aqueous solution in a humid chamber by spraying with a sprayer.

10. The method according to claim 9, wherein, An elongated, tortuous transport path for the foil structure, achieved by deflection rollers, is set up in the wet chamber.

11. The method according to claim 1, wherein, In step d), mechanical force is applied to the foil structure by means of ultrasonic waves and / or by means of a brush and / or by means of a felt plate or by means of a felt-covered roller and / or by means of a high-pressure nozzle.

12. The method according to claim 1, wherein, The water-soluble release layer is based on a material selected from the group consisting of: polyvinylpyrrolidone, modified starch, polyacrylic acid, polyethylene glycol, hydroxypropyl cellulose, hydroxyethyl cellulose, casein, gum arabic, carboxymethyl cellulose, polyvinyl alcohol, dextrin, or a mixture of at least two of the above materials.

13. The method according to claim 1, wherein, Water-soluble release layer has a concentration of 0.05 to 20 g / m³. 2 The coating weight within the range.

14. The method according to claim 1, wherein, The water-soluble release layer has a thickness ranging from 0.05 to 20 µm.

15. The method according to claim 1, wherein, The pigment material layer is a thin-layer system with optically variable effects, namely, a thin-layer element that changes color when tilted, giving the observer different color impressions at different viewing angles.

16. The method according to claim 15, wherein, The tilt-sensitive color-changing thin-film element has an additional magnet layer for the magnetic orientation of the pigment.

17. The method according to claim 15, wherein, The tilt-sensitive color-changing thin-film element has a reflective layer, a dielectric spacer layer, and an absorption layer.

18. The method according to claim 17, wherein, The tilt-color-changing thin-layer element is formed in a symmetrical multilayer arrangement, wherein the symmetrical multilayer arrangement has the following layer sequence: absorption layer - dielectric spacer layer - reflective layer - dielectric spacer layer - absorption layer.

19. The method according to claim 18, wherein, The sequence can include an additional magnet layer.

20. The method according to claim 18, wherein, The tilt-colored thin-layer element is formed in a symmetrical multilayer arrangement, wherein the symmetrical multilayer arrangement has the following sequence: Cr / SiO2 / Al / SiO2 / Cr, Al / SiO2 / Al / SiO2 / Al, or Cr / SiO2 / Al / FeSi / Al / SiO2 / Cr.

Images