Multi-Layer Body and Method for Producing Same

Abstract

The invention relates to a multilayer body with a carrier film, a partial reflective layer, arranged on the surface of the carrier film, which is at least partially transparent in a first area and opaque in a second area, a partial decorative layer, arranged on a surface of the carrier film and/or the side of the decorative layer facing away from the carrier film, which is present in a third area and not present in a fourth area,
wherein the first area overlaps the third area and the second area overlaps the third and the fourth areas.

The invention furthermore relates to a method for producing such a multilayer body, a security element with such a multilayer body and a security document with such a security element.

Claims

1. A multilayer body comprising: a carrier film, a partial reflective layer, arranged on the surface of the carrier film, which is at least partially transparent in a first area and opaque in a second area, and a partial decorative layer, arranged on a surface of the carrier film and/or the side of the reflective layer facing away from the carrier film, which is present in a third area and not present in a fourth area, wherein the first area overlaps the third area and the second area overlaps the third and the fourth areas, with the result that the second area masks a boundary line of the decorative layer.

2. The multilayer body according to claim 1, wherein the decorative layer comprises at least one dye, pigment, metal layer, effect pigment, thin-film system, magnetic thin-film system, and/or cholesteric liquid crystal system.

3. The multilayer body according to claim 1, wherein the third area forms at least one motif, image, symbol, logo and/or alphanumeric character.

4. The multilayer body according to claim 1, wherein the decorative layer is or comprises single- or multicolored raster or vector graphics.

5. The multilayer body according to claim 1, wherein a layer thickness of the decorative layer is from 5 nm to 500 μm.

6. The multilayer body according to claim 1, wherein the reflective layer is formed at least partially, in the first area, as a metal layer, made of Cu, Ag, Au, Al, Cr or alloys or combinations thereof.

7. The multilayer body according to claim 6, wherein the first area is formed as a grid of first partial areas, in which the reflective layer is present, and second partial areas, in which the reflective layer is not present.

8. The multilayer body according to claim 7, wherein the grid is a dot or line grid.

9. The multilayer body according to claim 7, wherein a grid width of the grid lies below a resolution limit of the human eye and is from 5 μm to 300 μm.

10. The multilayer body according to claim 9, wherein the grid width varies over the first area, according to a predetermined gradient along at least one spatial direction.

11. The multilayer body according to claim 7, wherein the first partial areas cover 20% to 80% of the surface of the first area.

12. The multilayer body according to claim 11, wherein the coverage of the first area by the first partial areas varies over the first area, according to a predetermined gradient along at least one spatial direction.

13. The multilayer body according to claim 7, wherein the decorative layer has at least partially a grid structure which forms a Moiré effect with the grid of the reflective layer.

14. The multilayer body according to claim 1, wherein the second area completely covers a boundary line between the third and the fourth areas.

15. The multilayer body according to claim 14, wherein the second area extends, at any point of the boundary lines, perpendicular to the boundary line by in each case a length into the third and the fourth areas, which length is at least the value of a register tolerance occurring when the decorative ply is produced.

16. The multilayer body according to claim 15, wherein the length is 0.2 mm to 2 mm.

17. The multilayer body according to claim 1, wherein the reflective layer is formed at least partially, in the second area, as an HRI (high refractive index) layer, made of ZnS, TiO.sub.2 or nanocomposites.

18. The multilayer body according to claim 1, wherein a layer thickness of the reflective layer is from 5 nm to 5000 nm.

19. The multilayer body according to claim 1, wherein the multilayer body has or comprises a replication layer with a surface relief.

20. The multilayer body according to claim 19, wherein the surface relief comprises one or more relief structures selected from the group diffractive grating, hologram, blazed grating, linear grating, cross grating, hexagonal grating, asymmetrical or symmetrical grating structure, retroreflective structure, microlens, microprism, Fresnel lens structure, free-form Fresnel lens structure, zero-order diffraction structure, moth-eye structure or anisotropic or isotropic mat structure, or a superimposition of two or more of the above-named relief structures.

21. The multilayer body according to claim 19, wherein a layer thickness of the replication layer is from 50 nm to 50 μm.

22. The multilayer body according to claim 1, wherein the carrier film comprises PET (polyethylene terephthalate), PEN (polyethylene naphthalate) or BOPP (biaxially oriented polypropylene).

23. The multilayer body according to claim 22, wherein a layer thickness of the carrier film is from 6 μm to 100 μm.

24. The multilayer body according to claim 22, wherein the multilayer body comprises a protective layer, made of a UV-curing varnish, of PVC, polyester or an acrylate, which is arranged between the carrier film and the decorative layer.

25. The multilayer body according to claim 24, wherein a layer thickness of the protective layer is from 1 μm to 20 μm.

26. The multilayer body according to claim 24, wherein the multilayer body comprises a detachment layer, made of a wax layer and/or a strongly filming acrylate, which is arranged between the carrier film and the protective layer.

27. The multilayer body according to claim 26, wherein a layer thickness of the detachment layer is from 5 nm to 1 μm.

28. The multilayer body according to claim 1, wherein the multilayer body has an adhesive layer which is arranged on the side of the reflective layer facing away from the carrier film.

29. The multilayer body according to claim 28, wherein a layer thickness of the adhesive layer is from 50 nm to 50 μm.

30. A method for producing a multilayer body, comprising: providing a carrier film, applying a partial reflective layer to the surface of the carrier film, wherein the reflective layer is at least partially transparent in a first area and opaque in a second area, applying a partial decorative layer to a surface of the carrier film and/or the side of the reflective layer facing away from the carrier film, wherein the decorative layer is applied in a third area of the surface and is not applied in a fourth area of the surface, and wherein the first area overlaps the third area and the second area overlaps the third and the fourth areas, with the result that the second area masks a boundary line of the decorative layer.

31. A method for producing a security document, comprising: providing a carrier film with a partial reflective layer, wherein the reflective layer is at least partially transparent in a first area and opaque in a second area, applying a partial decorative layer to a surface of the security document, wherein the decorative layer is applied in a third area of the surface and is not applied in a fourth area of the surface, transferring the partial reflective layer to the decorative layer, with the result that the first area overlaps the third area and the second area overlaps the third and the fourth areas, with the result that the second area masks a boundary line of the decorative layer.

32. The method according to claim 30, wherein the decorative layer is applied at least in areas by screen printing, gravure printing, inkjet printing, die stamping or offset printing.

33. The method according to claim 30, wherein the decorative layer is applied at least in areas by varnishing, casting, dipping and/or metalization.

34. The method according to claim 30, wherein the reflective layer is applied by sputtering, metalization or gas-phase deposition.

35. The method according to claim 30, wherein the reflective layer is partially applied.

36. The method according to claim 30, wherein the reflective layer is firstly applied over the whole surface and is subsequently structured.

37. A security element, obtained by transferring the layers of a multilayer body according to claim 1 detached from the carrier film.

38. A security with a security element according to claim 37.

Description

[0088] The invention is now explained in more detail with reference to embodiment examples. There are shown in:

[0089] FIG. 1 A schematic sectional representation of an embodiment example of a multilayer body with a decorative layer, a reflective layer and a carrier film with a diffractive surface relief;

[0090] FIG. 2 A schematic top view of an embodiment example of a multilayer body with a decorative layer which is bordered by a continuously opaque metal layer;

[0091] FIG. 3 A schematic top view of an embodiment example of a multilayer body with a decorative layer which is bordered by an opaque metal layer with a diffractive pump effect;

[0092] A multilayer body labeled as a whole with 1 comprises a carrier film 11, to which a partial metal layer 12 is applied. A partial decorative layer 13 is applied to the side of the metal layer 12 facing away from the carrier film 11, which layer is in turn covered over the whole surface by an adhesive layer 14.

[0093] The carrier film 11 has a detachment layer 112, a protective layer 113 and a replication layer 114.

[0094] The carrier film 11 preferably consists of PET, PEN or BOPP and preferably has a layer thickness of from 3 μm to 100 μm, particularly preferably from 6 μm to 50 μm.

[0095] The detachment layer 112, in particular made of a wax layer and/or a strongly filming acrylate, which is arranged between the carrier film 11 and the protective layer 113, adjoins the carrier film 11.

[0096] The detachment layer 112 facilitates the simple and damage-free detachment of the carrier film 11 from the remaining layers of the multilayer body 1 during application of the multilayer body 1 to an object. A layer thickness of the detachment layer is from 5 nm to 1 μm, preferably from 10 nm to 1 μm.

[0097] After detachment of the carrier film 11, the protective layer 113 thus forms the surface of the multilayer body 1 accessible from the outside and thus protects the sensitive further layers of the multilayer body from environmental influences, dirt, scratches and the like.

[0098] The protective layer 113 preferably consists of a UV-curing varnish, of PVC, polyester or an acrylate and has a layer thickness of from 1 μm to 20 μm, preferably from 3 μm to 10 μm.

[0099] The replication layer 114 adjoining the protective layer 113 consists of a replication varnish, preferably of a thermoplastic or UV-curing varnish, with a layer thickness of from 50 nm to 50 μm, preferably from 200 nm to 1 μm.

[0100] A surface relief is introduced into the surface of the replication layer 114 facing away from the protective layer 113. This comprises one or more relief structures selected from the group diffractive grating, hologram, blazed grating, linear grating, cross grating, hexagonal grating, asymmetrical or symmetrical grating structure, retroreflective structure, microlens, microprism, Fresnel lens structure, free-form Fresnel lens structure, zero-order diffraction structure, moth-eye structure or anisotropic or isotropic mat structure, or a superimposition of two or more of the above-named relief structures. Complex effects, in particular those which appear to be three-dimensional and can vary depending on the observation direction, can hereby be realized.

[0101] The reflective layer 12 is applied to the replication layer 114. This can be formed as a metal layer, preferably made of Al, Cr, Cu. Ag, Au or alloys/combinations thereof.

[0102] Alternatively or additionally, the use of highly refractive materials (HRI=high refractive index), in particular of ZnS, TiO.sub.2 or also of so-called nanocomposites is also possible. A layer thickness of the reflective layer is preferably from 5 nm to 5000 nm, particularly preferably from 20 nm to 100 nm.

[0103] The named materials can also be combined with each other in order thus to realize more complex optical impressions.

[0104] The reflective layer 12 has a first area 121 in which it is at least partially transparent, i.e. has a transmissivity of more than 30%. In a second area 122, the reflective layer is opaque, i.e. has a transmissivity of less than 30%.

[0105] In the examples shown in FIGS. 2 and 3, the first area 121 is formed as a grid of first partial areas, in which the reflective layer is present, and second partial areas, in which the reflective layer is not present.

[0106] Although partial areas are therefore present, in which a reflective layer is present in the first area 121, the first area 121 is still transparent in the meaning of the definition given above due to the arrangement in a grid. Through the arrangement in a grid, further graphic effects can be realized. In particular it is possible for the decorative layer 13 to be visible through the reflective layer 12 in the first area, wherein at the same time a slightly metallic impression forms through the arrangement in a grid.

[0107] The grid is preferably a dot or line grid. In the examples shown in the figures it is a line grid in the form of hatching.

[0108] The dots or lines of the grid can be arranged regularly, vary according to a predetermined function or also be distributed stochastically. The grid dots of a dot grid can, in the simplest case, be circular, but also have any other geometries. Microstructured items of information such as texts or logos can also be inscribed in the grid dots.

[0109] A grid width of the grid is preferably below a resolution limit of the human eye and in particular from 5 μm to 300 μm, preferably from 30 μm to 200 μm. The grid thus cannot be resolved by the human eye and can only be recognized as an effect superimposed on the decorative layer 13, for example as a slightly metallic impression.

[0110] The grid width can vary over the first area 121, preferably according to a predetermined gradient along at least one spatial direction. For example, a continuous or stepwise transition between the transparent 121 and the opaque areas 122 of the reflective layer 12 can hereby be created or a variation of the metallic impression over the grid can be realized.

[0111] The metallic areas of the grid preferably cover 20% to 80%, preferably 30% to 70%, further preferably 20% to 50% of the surface of the first area 121. In the case of such a surface coverage by the reflective layer 12, the first area 121 still appears transparent to the human eye. A completely opaque-metallic impression first arises in the case of coverage of more than 90%.

[0112] The coverage of the first area 121 by the reflective layer 12 can vary over the first area 121, preferably according to a predetermined gradient along at least one spatial direction. The transparency and/or the metallic impression can hereby be varied in the first area 121, whereby additional, optically attractive effects can be realized.

[0113] The decorative layer 13 is applied to the reflective layer 12. This preferably comprises at least one dye, pigment, metal layer, effect pigment, in particular an optically variable printing ink such as e.g. an OVI®, thin-film system, magnetic thin-film system, and/or cholesteric liquid crystal system. The named components of the decorative layer 13 can also be combined in order thus to obtain complex decorations which are to be imitated only with difficulty and guarantee a high degree of protection against forgery.

[0114] It is preferred if the decorative layer forms at least one motif, image, symbol, logo and/or alphanumeric character. These elements can be present singly, but also in combination and can be purely decorative, but also informative, i.e. for example indicate the denomination of a banknote or the like.

[0115] Such decorations can be realized for example as single- or multicolored raster or vector graphics.

[0116] Suitable processes for producing the decorative layer 13 are printing, in particular screen printing, gravure printing, inkjet printing, die stamping (intaglio printing) or offset printing, but also varnishing, casting, dipping and/or metalization.

[0117] The named processes can also be combined with each other in order for example to produce decorative layers with several printed plies and complex optical effects.

[0118] A layer thickness of the decorative layer is preferably from 5 nm to 500 μm, preferably from 50 nm to 100 μm, particularly preferably from 500 nm to 50 μm.

[0119] The decorative layer 13 covers the transparent area 121 of the reflective layer 12 and extends beyond it into the opaque area 122.

[0120] Since the opaque area 122 of the reflective layer 12 thus overlaps both the decorative layer 13 and the decoration-free area of the multilayer body, the opaque area 122 thus masks the boundary line or the outer contour of the decoration. In other words, both the decorative layer 13 and the reflective layer 12 can be applied with a certain register error, i.e. with a certain positional tolerance or positional inaccuracy relative to each other, which does not become noticeable due to this masking.

[0121] As FIGS. 2 and 3 show, the opaque area 122 preferably extends along the boundary surface of the decorative layer 13 and covers its boundary line or outer contour.

[0122] The entire outer contour of the decorative layer 13 is thus covered by the opaque area 122 of the reflective layer 12, with the result that any register errors can be concealed over the entire outer contour.

[0123] It is particularly preferred if the opaque area 122 extends, at any point of these boundary lines, perpendicular to the boundary line by in each case a length away from the boundary line, wherein the length at least corresponds in value to a register tolerance occurring when the decorative ply 13 is produced.

[0124] The described complete concealment of register errors over the entire outer contour of the decorative layer 13 at the same time as minimal surface coverage is hereby achieved by the opaque area 122. Through the symmetrical extension of the opaque area 122 of the reflective layer 12 along the outer contour, an attractive edge of the visible area of the decorative layer 13 is created at the same time.

[0125] As can be seen in FIG. 3, the opaque area 122 can also be used in combination with the relief structure in the replication layer to produce additional effects. By varying the angle of inclination of micromirrors or the azimuth angle of a blazed grating the tilt effect illustrated schematically in FIG. 3 can for example be achieved, with the result that a reflective zone in the opaque area 122 migrates from the inside outwards or vice versa on tilting the multilayer body 1.

[0126] The decorative layer 13 and the reflective layer 12 are finally also covered by the adhesive layer 14, with which the multilayer body 1 can be attached to an object.

[0127] This can be a hot-melt adhesive, a cold adhesive, an optically or thermally activatable adhesive or the like. The layer thickness of the adhesive layer is from 50 nm to 50 μm, preferably from 0.5 μm to 10 μm.

LIST OF REFERENCE NUMBERS

[0128] 1 multilayer body [0129] 11 carrier film [0130] 112 detachment layer [0131] 113 protective layer [0132] 114 replication layer [0133] 12 reflective layer [0134] 121 transparent area [0135] 122 opaque area [0136] 13 decorative layer [0137] 14 adhesive layer