THERMOCHROMIC SECURITY ELEMENT AND METHOD FOR PRODUCING A THERMOCHROMIC SECURITY ELEMENT

Abstract

A security element (1) as well as a method for producing a security element (1). The security element (1), in particular a security strip or a security thread or a patch or a transfer film (2) or a laminating film or a print, for protecting security documents (3), includes at least one thermochromic element (11), wherein i) the at least one thermochromic element (11) has haptic properties; and/or ii) the security element (1) has at least one haptic layer (12).

Claims

1. A security element for protecting security documents, wherein the security element has at least one thermochromic element, and wherein i) the at least one thermochromic element has haptic properties; and/or ii) the security element has at least one haptic layer.

2. The security element according to claim 1, wherein the security element comprises a carrier layer and/or at least one primer and/or at least one protective varnish layer.

3. The security element according to claim 2, wherein the at least one primer is arranged on the side of the carrier layer opposite the at least one thermochromic element.

4. The security element according to claim 2, wherein the at least one protective varnish layer is arranged above the at least one thermochromic element.

5. The security element according to claim 2, wherein the security element has a transfer ply detachable from the carrier layer.

6. The security element according to claim 5, wherein the at least one primer is arranged such that it is arranged under the at least one thermochromic element after application of the transfer ply to a target substrate.

7. The security element according to claim 5, wherein the at least one protective varnish layer is arranged such that it is arranged over the at least one thermochromic element after application of the transfer ply to a target substrate.

8. The security element according to claim 2, wherein the security element comprises a detachment layer.

9. The security element according to claim 5, wherein the transfer ply or the security element has a decorative ply.

10. The security element according to claim 1, wherein the at least one thermochromic element is arranged over the whole surface or at least in regions.

11. The security element according to claim 9, wherein at least one metal layer is arranged under the at least one thermochromic element.

12. The security element according to one of claim 9, wherein the at least one thermochromic element is designed as an etch resist for the structuring of the at least one metal layer and/or as an exposure mask for the structuring of an etch resist.

13. The security element according to claim 1, wherein the at least one thermochromic element has a color change point in a temperature range of from −20° C. to 120° C., with the result that when this color change point is exceeded the appearance of the at least one thermochromic element changes from a first color to a second color, and/or when this color change point is fallen below the appearance of the at least one thermochromic element changes from the second color to a first color.

14. The security element according to claim 1, wherein the at least one thermochromic element comprises at least one thermochromic colorant, and/or wherein the at least one thermochromic element comprises a first varnish layer with at least one thermochromic colorant and a second varnish layer with at least one colorant.

15. The security element according to claim 1, wherein the at least one thermochromic element comprises a first varnish layer with at least one first thermochromic colorant and a second varnish layer with at least one second thermochromic colorant.

16. The security element according to claim 14, wherein the first varnish layer and the second varnish layer have a color difference ΔE in the range of from 50 to 270.

17. The security element according to claim 1, wherein the at least one thermochromic element has a color change duration of less than 5 seconds.

18. The security element according to claim 13, wherein the at least one thermochromic element is oriented towards a visible face, which is visible for the observer, and wherein layers arranged underneath the at least one thermochromic element provide at least one item of information which is at least partially or completely concealed from an observer in the case of a temperature range below the color change point from the first color of the at least one thermochromic element and is visible for the observer in the case of a temperature range above the color change point because of the second color of the thermochromic element.

19. The security element according to claim 1, wherein the proportion of a thermochromic component in the at least one thermochromic element lies in the range of from 20% to 80%.

20. The security element according to claim 1, wherein the at least one thermochromic element comprises solids, and solvents.

21. The security element according to claim 1, wherein the at least one thermochromic element has a solids content in the range of from 20 wt.-% to 80 wt.-%.

22. The security element according to claim 1, wherein the at least one thermochromic element has a thermal conductivity in the range of from 0.001 W/m*K to 8000 W/m*K.

23. The security element according to claim 1, wherein the at least one haptic layer comprises three-dimensional structures with different height and/or depth.

24. The security element according to claim 23, wherein the at least one haptic layer is arranged underneath the at least one thermochromic element.

25. The security element according to claim 23, wherein the three-dimensional structures of the at least one haptic layer are designed as dots, waves, lines and/or combinations thereof and/or as a decorative element.

26. The security element according to claim 1, wherein the at least one haptic layer and/or the at least one thermochromic element comprises replicated structures, and/or wherein the at least one haptic layer and/or the at least one thermochromic element has additives.

27. The security element according to claim 1, wherein the at least one thermochromic element comprises three-dimensional structures with different height and/or depth for generating the haptic properties.

28. The security element according to claim 27, wherein the three-dimensional of the structures of the at least one thermochromic element form through variation of the print thickness and/or through the addition of additives.

29. The security element according to claim 27, wherein the three-dimensional structures of the at least one thermochromic element are designed as dots, waves, lines and/or combinations thereof and/or as a decorative element.

30. A method for producing a security element, wherein the following steps are carried out: providing at least one thermochromic element and/or applying at least one thermochromic element to a target substrate or a carrier layer, wherein i) the at least one thermochromic element has haptic properties; and/or ii) at least one haptic layer is applied.

31. The method according to claim 30, wherein the method further comprises the following step: providing a carrier layer.

32. The method according to claim 30, wherein the method further comprises the following step: applying at least one primer.

33. The method according to claim 30, wherein the method further comprises the following step: applying a transfer ply detachable from the carrier layer.

34. The method according to claim 31, wherein the method further comprises the following step: applying a detachment layer to the carrier layer by means of printing processes.

35. The method according to claim 33, wherein the transfer ply has a decorative ply.

36. The method according to claim 35, wherein the at least one thermochromic element is applied over the at least one metal layer.

37. The method according to claim 30, wherein structures replicated into at least one haptic layer and/or the at least one thermochromic element are introduced and/or wherein additives are introduced into the at least one haptic layer and/or the at least one thermochromic element.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0144] The invention is explained by way of example in the following with reference to several embodiment examples with the aid of the attached drawings. The embodiment examples shown are therefore not to be understood as limitative.

[0145] FIGS. 1a, b in each case show a schematic representation of a layer structure of a security element

[0146] FIGS. 2a, b in each case show a schematic representation of a layer structure of a security element

[0147] FIG. 3 shows a schematic representation of a security element as a transfer film

[0148] FIG. 4 shows a schematic representation of a security element as a transfer film

[0149] FIG. 5 shows a schematic representation of a layer structure of a security element

[0150] FIG. 6 shows a schematic representation of a security document with an applied security element

[0151] FIG. 7 shows a schematic representation of a security document with an applied security element

[0152] FIG. 8 shows a schematic representation of a security document with an applied security element

[0153] FIG. 9 shows a schematic representation of a security document with an applied security element

[0154] FIG. 10 shows a schematic representation of a security document with an applied security element

[0155] FIG. 11 shows a schematic representation of a security document with an applied security element

[0156] FIG. 12 shows a schematic representation of a security document with an applied security element

[0157] FIG. 13 shows a schematic representation of a security document with an applied security element

[0158] FIG. 14 shows a graph of the transmittance of a thermochromic element with a layer thickness of from 1.0 μm to 1.8 μm for different wavelengths depending on the color

[0159] FIG. 15 shows a graph of the transmittance of a thermochromic element with a layer thickness of from 1.6 μm to 2.4 μm for different wavelengths depending on the color

[0160] FIG. 16 shows a graph of the transmittance of a thermochromic element with a layer thickness of from 2.7 μm to 3.3 μm for different wavelengths depending on the color

[0161] FIG. 17 shows a graph of the transmittance of a thermochromic element with a layer thickness of from 3.6 μm to 4.4 μm for different wavelengths depending on the color

DETAILED DESCRIPTION

[0162] FIG. 1a shows a schematic representation of a security element 1, wherein the security element 1 has a thermochromic element 11 and wherein the thermochromic element 11 has haptic properties. By haptic properties is meant here the three-dimensional structures with elevations and depressions of the thermochromic element 11. These can preferably be sensed by humans when touched. These three-dimensional structures preferably have a height and/or depth in the range of from 0.1 μm to 70 μm, preferably from 0.5 μm to 50 μm, particularly preferably from 0.5 μm to 30 μm. These three-dimensional structures can be generated for example by different layer thicknesses, in particular during printing. However, it is additionally or alternatively also possible for the printed thermochromic element 11, preferably in the not yet cured state, to be structured by means of a stamp or a roller, with the result that these three-dimensional structures form.

[0163] If the security element 1 is used as a transfer film, in particular as a stamping film, it can also make sense to introduce the thermochromic element 11 into the adhesion-promoter layer. If the thermochromic element 11 also has haptic properties, then the haptic properties can be brought about by the locally different application weight of the adhesion-promoter layer. In addition to or instead of a different level of application weight of the adhesion-promoter layer in the decoration, the haptic properties can result from additives or thermochromic elements 11 themselves.

[0164] FIG. 1b shows a schematic representation of a security element 1, wherein the security element 1 has a thermochromic element 11 and wherein the security element 1 has a haptic layer 12. In this embodiment variant, the haptic properties are generated by the haptic layer 12.

[0165] It is preferably provided that the at least one haptic layer 12 comprises three-dimensional structures with different height and/or depth, in particular wherein the three-dimensional structures has a height and/or depth in the range of from 0.1 μm to 70 μm, preferably from 0.5 μm to 50 μm, particularly preferably from 0.5 μm to 30 μm. These three-dimensional structures can be sensed or felt by humans through touch. Here too, the three-dimensional structures can be realized by means of different application thicknesses of the print and/or structures can be introduced into the at least one haptic layer 12 by means of a stamp and/or a roller.

[0166] In the embodiment variant shown in FIG. 1b the haptic layer 12 is arranged underneath the thermochromic element 11, wherein the at least one thermochromic element 11 adapts to the three-dimensional structures of the at least one haptic layer 12. The thermochromic element 11 is also arranged over the whole surface of the haptic layer 12 in this embodiment. However, in advantageous designs it is also possible for the thermochromic element 11 to be arranged over the haptic layer 12 at least in regions.

[0167] A further schematic layer structure of a security element 1 is shown in FIG. 2a. In particular, it is provided that the security element 1 according to FIG. 2a is designed as a security strip. The security element 1 shown in FIG. 2a comprises three thermochromic elements 11, which are partially applied to the carrier layer 13. These can be applied by partial printing, for example. Further, the security element 1 comprises a primer 14, which is arranged on the side of the carrier layer 13 opposite the thermochromic elements 11. It is preferred that the carrier layer 13 has a thickness in the range of from 1 μm to 500 μm, preferably from 3 μm to 75 μm, particularly preferably from 6 μm to 50 μm.

[0168] It can also be provided that the carrier layer 13 has at least one adhesion-promotor layer, in particular wherein the adhesion-promoter layer has a thickness in a range of from 1 nm to 5 μm, preferably from 5 nm to 3 μm. The adhesion-promoter layer increases the adhesion between two layers which would otherwise not have sufficient adhesion to each other. This can be for example the adhesion between the carrier layer 13 and the thermochromic element 11.

[0169] An alternative design of a security element 1, in particular as a security strip, is shown in FIG. 2b. The security element 1 comprises a carrier layer 13 and a haptic layer 12, which is applied to the carrier layer 13 and over the whole surface of which a thermochromic element 11 is arranged. The haptic layer 12 again has the three-dimensional structures explained from FIG. 1b, to which the thermochromic element 11 adapts. A primer 14 is arranged on the side of the carrier layer 13 opposite the thermochromic element 11. This primer 14 can as a rule represent an adhesive layer or a system of several adhesive layers.

[0170] FIG. 3 shows a schematic structure of a security element 1, in particular as a transfer film 2. The security element 1 comprises a carrier layer 13 and a transfer ply 21 detachable from the carrier layer 13. The transfer ply 21 comprises three partially arranged thermochromic elements 11, a primer 14 and a protective varnish layer 15. In the design shown in FIG. 3 the security element 1 comprises a detachment layer 16, which is arranged between the carrier layer 13 and the transfer ply 21.

[0171] In the design shown in FIG. 3 the primer 14 is arranged such that it is arranged under the thermochromic elements 11 after application of the transfer ply 21 to a target substrate. On the other hand, the protective varnish layer 15 is arranged such that it is arranged over the thermochromic elements 11 after application of the transfer ply 21 to a target substrate. The protective varnish layer 15 has the function of protecting the thermochromic elements 11 from external environmental influences, such as for example mechanical, physical or chemical stress. In particular, it is provided that the protective varnish layer 15 adapts to the three-dimensional structures of the at least one thermochromic element 11. As a result, on the one hand the necessary protective effect can be ensured and on the other hand due to this design the haptic properties or the three-dimensional structures remain able to be sensed or felt by humans when touching the security element 1.

[0172] A further embodiment example of a security element 1 as a transfer film 2 is schematically represented in FIG. 4. The security element 1 comprises a carrier layer 13 and a transfer ply 21 detachable from the carrier layer 13. The transfer ply 21 comprises the primer 14, three thermochromic elements 11, a decorative ply 17, as well as a protective varnish layer 15. In addition, a detachment layer 16 is arranged between the transfer ply 21 and the carrier layer 13.

[0173] The decorative ply 17 preferably comprises at least one color layer and/or at least one replication varnish layer and/or at least one metal layer and/or at least one lens layer. Further, it is possible for the decorative ply 17 to be molded over the whole surface or patterned, for example in the form of alphanumeric characters, patterns, symbols or motifs. Further, it is expedient if the decorative ply 17 comprises further optically variable layers, for example with elements and/or substances, individually or in combination, selected from: optically variable pigments, holograms, blazed gratings, relief structures, Kinegram®, optical diffraction structures, lenses, prisms, thin film layers or liquid crystals. Thus, it is advantageous if the decorative ply 17 has at least one layer with a decorative effect.

[0174] As can be seen in FIG. 4, the decorative ply 17 is partially applied. The two partial decorative plies 17 on the right are at least partially covered by the thermochromic elements 11. If the color change point of the thermochromic element 11 is exceeded due to heat, the decorative plies 17 arranged under the thermochromic elements 11 become visible for the observer. Thus, items of information of the decorative plies 17 can be concealed at temperatures below the color change point of the thermochromic element 11, and these become visible when this color change point is exceeded. Unique security elements 1 can thereby be provided which can additionally be checked for their authenticity by the user or observer in a simple manner by touch and the associated heat transfer.

[0175] As can also be seen in FIG. 4, a decorative ply 17 can also stand alone and provide an item of information that is permanently visible for the observer. In other words, the decorative ply 17 is not covered by a thermochromic element 11. This is the case in the left-hand decorative ply 17 in FIG. 4.

[0176] A further design of a security element 1, in particular as a security strip, is represented schematically in FIG. 5. The security element 1 comprises a carrier layer 13 and a primer 14 arranged under the carrier layer 13. Decorative plies 17, and a partial thermochromic element 11, are partially arranged on the top side of the carrier layer 13. A thermochromic element 11 is arranged in each case over the two right-hand decorative plies 17. These cover the decorative ply 17 at least partially. It is also possible for the decorative ply 17 to be completely covered by the thermochromic element 11.

[0177] Furthermore, the decorative ply 17 can also comprise a haptic layer 12, which generates three-dimensional structures, or the decorative ply 17 itself can be a haptic layer 12 and can itself generate three-dimensional structures. In combination with the thermochromic elements 11, which likewise have haptic properties, various tactile structures, which can be sensed by an observer, can thus be generated.

[0178] FIG. 6 shows a security document 3 with a security element 1 applied thereto. The security document 3 is preferably a banknote substrate made of paper or a polymer. In the design shown, the transfer ply 21 of a hot-stamping film has been applied to the security document 3 in the form of a strip on the security document 3. In particular, it is provided that the transfer ply 21 comprises an adhesive layer, in particular a hot-glue layer, which is thermally activated by a heatable embossing die or an embossing roller. A firm bond between security document 3 and transfer ply 21 or security element 1 is produced through the activation of the adhesive layer. In particular, it is also provided that the adhesive layer is cured by means of radiation, in particular UV radiation. It can also be provided that the adhesive is applied to the transfer ply 21 or to the security document 3 immediately before application of the transfer ply 21. Here too, the adhesive is then cured, in particular by means of UV radiation.

[0179] The security element 1 shown in FIG. 6 comprises four thermochromic elements 11 in the shape of circles, i.e. the thermochromic element 11 is only partially arranged in the security element 1.

[0180] A further design variant of a security document 3 with a security element 1 applied thereto is represented in FIG. 7. The transfer ply 21 of a hot-stamping film has been applied to the security document 3 in the form of a strip. In contrast to the embodiment variant shown in

[0181] FIG. 6, in the embodiment shown in FIG. 7 the thermochromic element 11 is arranged over the whole surface. In other words, the entire security element 1 has thermochromic properties, with the result that it generates a color change in the case of heat input. However, the color change is only effected locally, at the point at which the heat is introduced, for example by being touched by a finger of an observer or user. Depending on the thermal conductivity of the thermochromic element 11, the heat can be conducted more quickly or more slowly inside the thermochromic element 11, with the result that points neighboring the heat input point can also perform a color change.

[0182] A further design of a security document 3 with a security element 1 applied thereto is represented in FIG. 8. Here, the security element 1 is designed as a patch, which has been applied to the security document 3 as a transfer ply 21 of a hot-stamping film by means of a hot embossing die. Alternatively, such a patch can also be applied as a cold-stamping film or as a laminating film. The security element 1 in the form of a patch has four partially arranged thermochromic elements 11 in the shape of circles. In addition, these thermochromic elements 11 have elevations and depressions as three-dimensional structures, which can be sensed or felt by humans when touched.

[0183] A further design variant of a security document 3 with a security element 1 applied thereto is represented in FIG. 9. The security element 1 is a strip which has been transferred onto or into the security document 3 as a transfer ply 21 of a hot-stamping film or a cold-stamping film or as a thread embedded in the document substrate or as a laminating film. The security element 1 comprises six thermochromic elements 11, which are designed in the shape of waves. The waves are raised compared with the rest of the security element 1, with the result that they generate a haptic surface which can be sensed by humans when touched. It is advantageous that the waves being touched is at the same time accompanied by a heat input, which ensures that the waves change their color. This is thus a double authentication of the security document 3 for its authenticity, wherein only one checking step, namely touching the waves, needs to be carried out. The observer takes the three-dimensional structures of the waves when touching them was and can additionally observe a color change of the waves.

[0184] FIG. 10 shows a further embodiment variant of a security document 3 with a security element 1 applied thereto. The structure is similar to the embodiment variant shown in FIG. 9, but with the difference that the thermochromic elements 11 with haptic properties are implemented as dots.

[0185] A further design variant of a security document 3 with a security element 1 applied thereto as a strip is represented in FIG. 11. The security element 1 comprises six thermochromic elements 11, which are designed in an alternating manner as a wave and as a dot. A diverse haptic impression can hereby be generated, as the observer has to perform a continuous movement along the strip when touching it, in order to be able to perceive all of the haptic impressions and to check the security element 1 for its authenticity. Through the continuous movement during the touching, a heat input is also effected over the entire length of the strip, with the result that the thermochromic elements 11 generate a color change because of the heat input by body heat.

[0186] FIG. 12 shows a further design of a security document 3 with a security element 1 applied thereto as a strip. The security element 1 has five thermochromic elements 11, wherein the outer two are designed as waves. The middle thermochromic element 11 is designed as a “20”, which is combined with freeform lenses. The freeform lenses are preferably arranged above the thermochromic element 11 and, because of the optical lens structure, suggest a surface relief, which is always visible for the observer. Due to the action of heat on the thermochromic element 11, the latter changes its color for example from blue to colorless. The optical lens effect persists and remains visible for the observer before and after the action of heat.

[0187] FIG. 13 shows a further schematic representation of a security document 3 with a security element 1 applied thereto. The security element 1 comprises four thermochromic elements 11. The first thermochromic element 11 is designed as a wave, the second thermochromic element 11 is designed as a dot, the third thermochromic element 11 is designed as a “20” with an optical lens structure and the fourth thermochromic element 11 is designed as a star. In the case of the action of heat and the resultant temperature change, a color change of the “20” from, for example, blue to colorless is brought about. In the case of the star, the thermochromic element 11 is arranged over a golden color layer, wherein the golden color layer is likewise formed as a star. The thermochromic element 11 is arranged register-accurate relative to the color layer. To the observer, the thermochromic element 11 appears black at a temperature below the color change point and colorless at a temperature above the color change point. Thus, if a heat input is effected on the star, the thermochromic element 11 thus changes its color from black to colorless in the region of the star. The golden color layer lying underneath it in the shape of a star becomes visible for the observer. With this arrangement of thermochromic element 11 above a color layer, all conceivable color combinations and color changes are possible, whereby a diverse optical impression is generated, which at the same time makes it possible to check the security element 1 for authenticity.

[0188] Results of a measurement of transmittances of different thermochromic elements 11 depending on the layer thickness and the respective color of the thermochromic element 11 are represented in FIGS. 14 to 17. For this purpose, different thermochromic elements 11 with different color impressions yellow g, blue b, pink r and black s have been used. In each case these have a color change point in a temperature range of from 25° C. to 30° C. The at least one thermochromic element 11 preferably has at least one color varnish, wherein the color varnish comprises at least one dye and at least one binder. The dye can be a combination of conventional and thermochromic colorants. The conventional and thermochromic colorants are preferably solids.

[0189] For the transmittance measurement, the thermochromic elements 11 or thermochromic layers were applied to a PET carrier and measured together with it. However, in order to determine the transmittance of the thermochromic elements 11 or of the thermochromic layers, the transmittance of the PET carrier without thermochromic layer was measured. During this measurement, it emerged that the PET carrier has a transmittance of approximately 90% in the wavelength range of from 300 nm to 800 nm, in particular from 300 nm to 500 nm. For the assessment of the measurement results, the effect of the PET carrier layer 13 can therefore be regarded as negligible.

[0190] The transmittance measurements of the thermochromic layers were carried out at room temperature, approx. 21° C., and thus below the color change point of the thermochromic elements 11.

[0191] To measure the transmittance, a spectrophotometer manufactured by Hitachi, with the model name U-2000, was used.

[0192] FIG. 14 shows the results of the transmittance measurements at a temperature of 21° C. for a yellow thermochromic layer g, a blue thermochromic layer b and a pink thermochromic layer r with a thickness in the range of from 1.0 μm to 1.8 μm in the wavelength range of from 300 nm to 500 nm. In particular, it is provided that the at least one thermochromic element 11 has a thickness in the range of from 1.0 μm to 1.8 μm and, in the wavelength range of from 300 nm to 800 nm, in particular from 300 nm to 500 nm, at a temperature in the range of from 20° C. to 25° C., has a transmittance of at most 70%, preferably at most 65%, particularly preferably at most 60%.

[0193] It is preferably also possible for the at least one thermochromic element 11 to have a thickness in the range of from 1.0 μm to 1.8 μm and to have a hue on the RAL chart selected from RAL 1000 to RAL 1037, in particular a yellow hue from the RAL Classic collection, and, in the wavelength range of from 300 nm to 800 nm, in particular from 300 nm to 500 nm, at a temperature in the range of from 20° C. to 25° C., to have a transmittance of at most 70%, preferably at most 65%, particularly preferably at most 60%.

[0194] It is preferably also possible for the at least one thermochromic element 11 to have a thickness in the range of from 1.0 μm to 1.8 μm and to have a hue on the RAL chart selected from RAL 5000 to RAL 5026, in particular a blue hue from the RAL Classic collection, and, in the wavelength range of from 300 nm to 800 nm, in particular from 300 nm to 500 nm, at a temperature in the range of from 20° C. to 25° C., to have a transmittance of at most 70%, preferably at most 65%, particularly preferably at most 60%.

[0195] It is preferably also possible for the at least one thermochromic element 11 to have a thickness in the range of from 1.0 μm to 1.8 μm and to have a hue on the RAL chart selected from RAL 4001 to RAL 4012, in particular a purple hue from the RAL Classic collection, and, in the wavelength range of from 300 nm to 800 nm, in particular from 300 nm to 500 nm, at a temperature in the range of from 20° C. to 25° C., to have a transmittance of at most 70%, preferably at most 65%, particularly preferably at most 60%.

[0196] FIG. 15 shows the results of the transmittance measurements at a temperature of 21° C. for a yellow thermochromic layer g, a blue thermochromic layer b, a black thermochromic layer s and a pink thermochromic layer r with a thickness in the range of from 1.6 μm to 2.4 μm in the wavelength range of from 300 nm to 500 nm. In particular, it is provided that the at least one thermochromic element 11 has a thickness in the range of from 1.6 μm to 2.4 μm and, in the wavelength range of from 300 nm to 800 nm, in particular from 300 nm to 500 nm, at a temperature in the range of from 20° C. to 25° C., has a transmittance of at most 50%, preferably at most 45%, particularly preferably at most 40%.

[0197] It is preferably also possible for the at least one thermochromic element 11 to have a thickness in the range of from 1.6 μm to 2.4 μm and to have a hue on the RAL chart selected from RAL 1000 to RAL 1037, in particular a yellow hue from the RAL Classic collection, and, in the wavelength range of from 300 nm to 800 nm, in particular from 300 nm to 500 nm, at a temperature in the range of from 20° C. to 25° C., to have a transmittance of at most 50%, preferably at most 45%, particularly preferably at most 40%.

[0198] It is preferably also possible for the at least one thermochromic element 11 to have a thickness in the range of from 1.6 μm to 2.4 μm and to have a hue on the RAL chart selected from RAL 5000 to RAL 5026, in particular a blue hue from the RAL Classic collection, and, in the wavelength range of from 300 nm to 800 nm, in particular from 300 nm to 500 nm, at a temperature in the range of from 20° C. to 25° C., to have a transmittance of at most 50%, preferably at most 45%, particularly preferably at most 40%.

[0199] It is preferably also possible for the at least one thermochromic element 11 to have a thickness in the range of from 1.6 μm to 2.4 μm and to have a hue on the RAL chart selected from RAL 4001 to RAL 4012, in particular a purple hue from the RAL Classic collection, and, in the wavelength range of from 300 nm to 800 nm, in particular from 300 nm to 500 nm, at a temperature in the range of from 20° C. to 25° C., to have a transmittance of at most 50%, preferably at most 45%, particularly preferably at most 40%.

[0200] It is preferably also possible for the at least one thermochromic element 11 to have a thickness in the range of from 1.6 μm to 2.4 μm and to have a hue on the RAL chart selected from RAL 9004, RAL 9005, RAL 9011, RAL 9017, in particular a black hue from the RAL Classic collection, and, in the wavelength range of from 300 nm to 800 nm, in particular from 300 nm to 500 nm, at a temperature in the range of from 20° C. to 25° C., to have a transmittance of at most 50%, preferably at most 45%, particularly preferably at most 40%.

[0201] FIG. 16 shows the results of the transmittance measurements at a temperature of 21° C. for a yellow thermochromic layer g, a blue thermochromic layer b, a black thermochromic layer s and a pink thermochromic layer r with a thickness in the range of from 2.7 μm to 3.3 μm in the wavelength range of from 300 nm to 500 nm. In particular, it is provided that the at least one thermochromic element 11 has a thickness in the range of from 2.7 μm to 3.3 μm and, in the wavelength range of from 300 nm to 800 nm, in particular from 300 nm to 500 nm, at a temperature in the range of from 20° C. to 25° C., has a transmittance of at most 40%, preferably at most 35%, particularly preferably at most 30%.

[0202] It is preferably also possible for the at least one thermochromic element 11 to have a thickness in the range of from 2.7 μm to 3.3 μm and to have a hue on the RAL chart selected from RAL 1000 to RAL 1037, in particular a yellow hue from the RAL Classic collection, and, in the wavelength range of from 300 nm to 800 nm, in particular from 300 nm to 500 nm, at a temperature in the range of from 20° C. to 25° C., to have a transmittance of at most 40%, preferably at most 35%, particularly preferably at most 30%.

[0203] It is preferably also possible for the at least one thermochromic element 11 to have a thickness in the range of from 2.7 μm to 3.3 μm and to have a hue on the RAL chart selected from RAL 5000 to RAL 5026, in particular a blue hue from the RAL Classic collection, and, in the wavelength range of from 300 nm to 800 nm, in particular from 300 nm to 500 nm, at a temperature in the range of from 20° C. to 25° C., to have a transmittance of at most 40%, preferably at most 35%, particularly preferably at most 30%.

[0204] It is preferably also possible for the at least one thermochromic element 11 to have a thickness in the range of from 2.7 μm to 3.3 μm and to have a hue on the RAL chart selected from RAL 4001 to RAL 4012, in particular a purple hue from the RAL Classic collection, and, in the wavelength range of from 300 nm to 800 nm, in particular from 300 nm to 500 nm, at a temperature in the range of from 20° C. to 25° C., to have a transmittance of at most 40%, preferably at most 35%, particularly preferably at most 30%.

[0205] It is preferably also possible for the at least one thermochromic element 11 to have a thickness in the range of from 2.7 μm to 3.3 μm and to have a hue on the RAL chart selected from RAL 9004, RAL 9005, RAL 9011, RAL 9017, in particular a black hue from the RAL Classic collection, and, in the wavelength range of from 300 nm to 800 nm, in particular from 300 nm to 500 nm, at a temperature in the range of from 20° C. to 25° C., to have a transmittance of at most 40%, preferably at most 35%, particularly preferably at most 30%.

[0206] FIG. 17 shows the results of the transmittance measurements at a temperature of 21° C. for a yellow thermochromic layer g, a blue thermochromic layer b, a black thermochromic layer s and a pink thermochromic layer r with a thickness in the range of from 3.6 μm to 4.4 μm in the wavelength range of from 300 nm to 500 nm. In particular, it is provided that the at least one thermochromic element 11 has a thickness in the range of from 3.6 μm to 4.4 μm and, in the wavelength range of from 300 nm to 800 nm, in particular from 300 nm to 500 nm, at a temperature in the range of from 20° C. to 25° C., has a transmittance of at most 30%, preferably at most 25%, particularly preferably at most 20%.

[0207] It is preferably also possible for the at least one thermochromic element 11 to have a thickness in the range of from 3.6 μm to 4.4 μm and to have a hue on the RAL chart selected from RAL 1000 to RAL 1037, in particular a yellow hue from the RAL Classic collection, and, in the wavelength range of from 300 nm to 800 nm, in particular from 300 nm to 500 nm, at a temperature in the range of from 20° C. to 25° C., to have a transmittance of at most 30%, preferably at most 25%, particularly preferably at most 20%.

[0208] It is preferably also possible for the at least one thermochromic element 11 to have a thickness in the range of from 3.6 μm to 4.4 μm and to have a hue on the RAL chart selected from RAL 5000 to RAL 5026, in particular a blue hue from the RAL Classic collection, and, in the wavelength range of from 300 nm to 800 nm, in particular from 300 nm to 500 nm, at a temperature in the range of from 20° C. to 25° C., to have a transmittance of at most 30%, preferably at most 25%, particularly preferably at most 20%.

[0209] It is preferably also possible for the at least one thermochromic element 11 to have a thickness in the range of from 3.6 μm to 4.4 μm and to have a hue on the RAL chart selected from RAL 4001 to RAL 4012, in particular a purple hue from the RAL Classic collection, and, in the wavelength range of from 300 nm to 800 nm, in particular from 300 nm to 500 nm, at a temperature in the range of from 20° C. to 25° C., to have a transmittance of at most 30%, preferably at most 25%, particularly preferably at most 20%.

[0210] It is preferably also possible for the at least one thermochromic element 11 to have a thickness in the range of from 3.6 μm to 4.4 μm and to have a hue on the RAL chart selected from RAL 9004, RAL 9005, RAL 9011, RAL 9017, in particular a black hue from the RAL Classic collection, and, in the wavelength range of from 300 nm to 800 nm, in particular from 300 nm to 500 nm, at a temperature in the range of from 20° C. to 25° C., to have a transmittance of at most 30%, preferably at most 25%, particularly preferably at most 20%.

LIST OF REFERENCE NUMBERS

[0211] 1 security element [0212] 11 thermochromic element [0213] 12 haptic layer [0214] 13 carrier layer [0215] 14 primer [0216] 15 protective varnish layer [0217] 16 detachment layer [0218] 17 decorative ply [0219] 2 transfer film [0220] 21 transfer ply [0221] 3 security document [0222] b blue thermochromic layer [0223] g yellow thermochromic layer [0224] r pink thermochromic layer [0225] s black thermochromic layer