The invention relates to methods for producing a multilayer film security element and relates in particular to the production of a multilayer film security element with a structured metallized embossed structure with recesses, in which the metallized areas of the embossed structure are formed on at least part of the security element at least partially colored.
Data carriers, such as value documents or identity documents, but also other valuables, such as branded articles, are often provided with security elements for securing purposes, which permit a verification of the authenticity of the data carrier and at the same time serve as protection against unauthorized reproduction. Increasingly transparent security features, such as transparent windows in banknotes, are becoming increasingly attractive.
For window production, for example, a film provided with an adhesive layer on one side is applied to a banknote in order to close a through opening previously introduced there. Typically, the film is provided with a security feature such as a hologram or optically variable coating to form a film security element. Double-sided diffractive optical security elements with recesses are for example from the publications EP 1 476 315 B1
. EP 1 458 585 B1
. EP 2 448 766 B1
or EP 2 448 767 B1
Also known are security films that carry a metallized embossed structure with recesses and in which the metallized areas of the embossed structure are formed on at least one side of the security element at least partially colored. The production of such security films is currently very complicated and requires several exposure steps and very well controlled production conditions.
Based on this, the object of the present invention is to specify simple and cost-effective methods for the production of film security elements of the type mentioned in the introduction.
This object is solved by the features of the independent claims. Further developments of the invention are the subject of the dependent claims.
The invention first provides a method for producing a multilayer film security element for security papers, value documents and other data carriers, in which
- a film carrier is provided and provided with a colored motif print,
- the printed film carrier is provided with an embossing lacquer layer, and the embossing lacquer layer is provided with an embossing structure,
- a soluble wash ink is applied to the embossing lacquer layer in the register complementary to the motif print,
- the embossing lacquer layer is coated with the applied wash paint with a metallization coating, and
- the coated embossing lacquer layer is subjected to a washing step in which the washing color is washed off by a solvent with at least part of the layer regions arranged above the washing color.
If several layers or embossings are produced in different printing processes in different printing units of a printing press or in different printing presses, then even with registered application or embossing certain register variations are technically unavoidable. Typical register variations are in the order of 0.1 mm when using various printing / embossing units of a printing press. In a so-called insetter operation, in which an intermediate product is printed / embossed registered in a further machine after printing / embossing in a first machine, the typical register variations are of the order of 0.2 mm.
The statement that the soluble washing ink is applied in the register complementary to the motif print, means that the wash is registered on the one hand applied to the motif print, but this happens in the context of registration accuracy only in areas where there is no motif print. Creative print and wash color are then complementary to each other.
In an advantageous variant of the method, one or more metal layers, for example aluminum, chromium, copper or alloys of these metals, are applied as metallization coating. With particular advantage, a multilayer structure, in particular with a layer sequence Metall1, dielectric spacer layer, Metall2 can be applied as the metallization coating.
In an advantageous variant, it is provided that the multilayer structure contains an ultrathin dielectric spacer layer with a thickness below 250 nm, in particular between 50 nm and 250 nm, in order to reflect in reflection and / or transmission to produce a fixed color. The multilayer structure may also include a thicker dielectric spacer layer having a thickness above 250 nm, with interference effects typically producing a color-shifting multilayer structure. The multilayer structure can particularly advantageously contain a dielectric spacer layer with locally varying layer thickness in order to generate locally different color impressions (different fixed color impressions and / or different tilt angle-dependent color impressions) in reflection and / or transmission. The dielectric spacer layer of the multi-layer structure may be vapor-deposited like the metal layers, but is advantageously printed.
In an advantageous embodiment, after applying the metallization coating, the film security element is subjected to said washing step, wherein in the washing step the wash color is washed off with the layer regions of the metallization coating arranged above the wash color. In all embodiments, a water-soluble wash can be used and water as the solvent.
In another, likewise advantageous embodiment, the metallization coating is provided before the washing step with a second colored motif print, which is preferably applied in register with the first colored motif print. The film security element is then advantageously subjected to the said washing step after application of the second colored motif print, wherein in the washing step, the wash ink is advantageously washed away with all the wash ink layer regions of the metallization coating and the second colored motif print by a solvent. Alternatively, it can also be provided that the film security element is subjected to the abovementioned washing step after application of the second colored motif print In the washing step, the washing ink is washed off only in the regions not provided with the second colored motif print with the layer regions of the metallization coating arranged above the wash ink.
In an advantageous embodiment, the embossing lacquer layer is provided with an embossed structure in register with the motif print, and the soluble wash ink is registered but applied in a complementary manner to the embossed structure.
In all embodiments, the embossing lacquer layer is advantageously applied over the entire surface. As an embossing pattern, a hologram, a micromirror structure, a microcavity structure, a microlens structure, nanostructures or Fresnel structures, in particular Fresnel concave mirrors or Fresnel convex mirrors, are advantageously embossed into the embossing lacquer layer.
The film carrier is advantageously pre-printed and the colored motif print is applied to a pressure-pretreated surface of the film carrier.
The first color motif print provided on the film carrier and / or the second color motif print on the metallization coating are advantageously carried out with colored inks, in particular with translucent multicolored inks.
The invention also provides a method for producing a multilayer film security element for security papers, value documents and other data carriers, in which
- a film carrier is provided,
- the film carrier is provided on one side with an embossing lacquer layer and the embossing lacquer layer is provided with a desired embossing structure and metallised,
- the film carrier is provided on both sides in supersimultaneous printing with structured printed motifs arranged precisely on the metallized side with first printing inks and on the non-metallized side with second printing inks, the first printing inks applied to the metallized side being formulated as a resist, and
- in an etching step, the areas of the metallization which are not covered with printing inks formulated as resist are removed.
The embossed structure of the embossing lacquer layer is preferably metallized over the entire area. As metallization, one or more metal layers, but also multi-layer structures of the type described above into consideration.
The structured motif prints can each be printed with differently colored printing inks, wherein in particular the printing inks applied to the metallized embossing lacquer layer can also be partially colorless.
The invention further provides a method for producing a multilayer film security element for security papers, value documents and other data carriers, in which
- a film carrier having a structured functional coating arranged on one side of the film carrier is provided, which in this order contains an embossing lacquer layer with desired first embossings, a first metallization, an optically separating intermediate layer with a second embossing, and a second metallization,
- the film carrier on the side of the structured functional coating or the side opposite the structured functional coating is provided with a colored photoresist layer in the form of a desired motif,
- the colored photoresist layer is exposed from the opposite side of the film carrier forth, so that the metallizations of the structured functional coating act as an exposure mask, and
- the exposed photoresist is developed to produce color regions matched to the structured functional coating.
The film carrier can be provided after the coating and development of the photoresist on one side in a second step on the other side with a second colored photoresist layer in the form of a desired motif. The second photoresist layer is then also exposed from the opposite side of the film carrier, the metallizations of the structured functional coating acting as an exposure mask. The exposed second photoresist is then developed to produce color regions matched to the patterned functional coating.
The one or more photoresists can be added for coloration in particular with soluble dyes or color pigments.
In all the embodiments described in the application in which photoresist is used, it may be a resist in which the exposed areas remain after development (negative resist) or a resist in which the unexposed areas remain (positive resist) , Thus, in all designs both resist structures can be produced that are congruent with the structures used as the exposure mask, as well as resist structures which are complementary to the structures used as the exposure mask.
Finally, in all designs, a coloration of structured resist material may also be effected by bringing a resist under pressure and / or temperature influence into a sticky state and bringing the sticky resist into contact with a colorant, such as color pigments.
Further exemplary embodiments and advantages of the invention are explained below with reference to the figures, in the representation of which a representation true to scale and proportion has been dispensed with in order to increase the clarity.
- Fig. 1
- a schematic representation of a banknote with a security element according to the invention in the form of a glued foil strip,
- Fig. 2
- in (a) to (c) intermediate steps in the production of a film which is to be applied as a film strip to a paper with a hole,
- Fig. 3
- in (a) and (b) intermediate steps in the production of a film, as in Fig. 2 as a foil strip to be applied to a paper with a hole, with a modified manufacturing method,
- Fig. 4
- in (a) and (b) intermediate steps in the production of a film, which can be used as a transfer strip,
- Fig. 5
- in (a) and (b) intermediate steps in a variant of the method of Fig. 4 in which the metallization coating is designed as a three-layer structure,
- Fig. 6
- in (a) and (b) intermediate steps in the production of a film which is to be applied as a film strip to a substrate with a transparent window, wherein the carrier film of the security element should remain in the product,
- Fig. 7
- in (a) to (e) intermediate steps in the manufacture of a film carrying two independent metallized imprints which are visible from opposite sides of the film and which are additionally provided with matched color layers for the purpose of producing color effects,
- Fig. 8
- in (a) to (e) further manufacturing variants of film security elements applied over a see-through window to be and in which the carrier film of the security element should remain in the product, and
- Fig. 9
- in (a) to (c) intermediate steps in the production of a film security element, which is provided by means of a transfer process with a structured colored layer.
The invention will now be explained using the example of security elements for banknotes. FIG. 1 shows a schematic representation of a banknote 10 with a security element according to the invention in the form of a glued foil strip 12, which covers a through opening 14 in the banknote paper. In the banknote window created thereby, a colored and at the same time shiny metallic motif 16 is visible, which in the exemplary embodiment is shown in the form of a maple leaf.
A special feature of the film strip 12 consists in the fact that the motif 16 in the window 14 from the opposite sides of the banknote 10 ago each metallic shiny, but appears with different colors.
Hereinafter, various manufacturing methods for producing such security elements with a metallic, different from opposite viewing directions color impression will be described in more detail.
Regarding Fig. 2 First, the production of a film is described, which is to be applied as a film strip on a paper with a hole, as well as in Fig. 1 shown. To produce a film strip 20, first a polyester film 22 having a thickness of between 6 μm and 36 μm is provided. Preferably, the polyester film 22 has a thickness of about 12 μm and is pretreated on one side for good adhesion of the applied layers (reference numeral 24). A desired colored motif print 28 is applied with printing inks 26 to the print-pretreated side of the polyester film 22, wherein any printing method, such as gravure printing or flexographic printing, can be used. The printing inks 26 may be aqueous, solvent-based and / or, more preferably, UV-crosslinking. The print can also be multicolored and carried out with several printing units. In this case, intermediate hardening or intermediate drying of first applied printing inks may be required.
An embossing lacquer layer 30 is then printed on the colored motif print 28, wherein the printing preferably takes place over the entire surface, so that no special register requirements are placed on the embossing lacquer printing. The embossing lacquer may be a thermoplastic embossing lacquer, however, the use of a UV embossing lacquer is currently preferred. The embossing lacquer layer 30 is provided with an embossment 32, which in the exemplary embodiment shown is in register with the colored motif print 28, that is to say the partial areas printed with printing inks 26. The embossing can be, for example, a hologram, a micromirror structure, a microcavity structure, a microlens structure, nanostructures or Fresnel structures.
Now registered on the embossment 32 is complementary, so substantially just in the unembossed areas of the embossing lacquer layer 30, a wash color 34 printed, so that the in Fig. 2 (a) Layer sequence shown arises. All work steps described so far are done in a single operation, so that a register accuracy of about 0.1 mm can be achieved.
In other embodiments, the embossment 32 can also go beyond the colored motif print 26 or even extend over the entire embossing lacquer layer 30. It is only important that the wash ink 34 is applied in the register complementary to the colored motif print 26.
Regarding Fig. 2 (b) Now, in a second operation, the embossing lacquer layer 30 and the washing ink 34 are provided over the entire surface with a metal layer 38. Then a second colored motif print 40 with second printing inks 36 is printed on the metal layer 38. The second colored motif print 40 can also be multicolored and be made with aqueous, solvent-based and / or UV-crosslinking printing inks. However, the colors of the second motif print 40 preferably differ at least in part from the colors of the first motif print 26, resulting in different color impressions. The second colored motif print 40 can be printed in an insetter process registered to the first colored motif print 28, wherein registration accuracies of about 0.2 mm can be achieved. The resulting layer sequence is in Fig. 2 (b) shown.
Now, a washing step is carried out in which the washing ink 34 is removed with the areas of the metal layer arranged above 38 and the areas of the second printing inks 36 disposed above, so that the in Fig. 2 (c) shown situation arises. The washing step produces a perfect registration of the remaining regions 42 of the metal layer 38 with the embossment 32 and with the remaining regions 44 of the second colored motif print 40.
As a result, a foil strip 20 is obtained, in which a metallized embossed structure 32, 42 is arranged in register with a colored first motif print 28 and colored areas 44 of a second motif print 40. The color areas 44 are visible from the upper side of the film strip 20 and the color areas 26 are visible from the underside. The color areas 26 and 44 are in each case separated by the metallized embossed pattern 32, 42.
As in Fig. 2 (b) and (c) The registration of the color regions 44 to the metallized embossed structure 32, 42 and thus to the color regions 26 may be complete (center of the image, reference numeral 45A) or may extend to only part of the outline of the color regions 26 (left image side, reference numeral 45B). , The color regions 44 may thus be formed in a pattern, such as a striped pattern, dot or line pattern, and yet be matched along their outer contours with the color regions 26. Furthermore, areas without a second printing ink 36 can also be provided, in which the film strip 20 shows the purely metallic appearance of the metallized embossed structure 32, 42 from the upper side (right-hand side of the picture, reference numeral 45C).
Alternatively, the second ink 36 may also be such that it is not removed along with the metallization 38 in the washing step. In particular, in this case, the area covered by the second printing ink 36 can always lie within the embossment 32, so that colored areas with a metallic edge remain after the washing step.
Instead of the washing process, it is also possible to use an etching process for structuring the metal layer 38, as will now be described with reference to FIG Fig. 3 explained. Also in this process variant is first a polyester film 22, which is preferably pressure-treated on one side (reference numeral 24). Then, a desired colored motif print 28 is printed with printing inks 26 onto the print-pretreated side of the polyester film 22 and a full-area embossing lacquer layer 30 is printed thereon. The embossing lacquer layer 30 is provided with an embossment 32, which is in register with the colored motif print 28, and the embossed lacquer layer 30 is finally provided with a metal layer 38 over its entire surface.
Then, in the insetter for embossing 32, a resist 50 and on this a second colored motif print 52 is printed with one or more second chromatic colors 54, so that the in Fig. 3 (a) Layer sequence shown arises.
Specifically, several different approaches are possible for the application of the bright colors 52. For example, the bright colors 54 may be printed after the resist 50 and show good adhesion to the resist 50 but relatively poor resist on the metal layer 38. During the subsequent etching step, the subregions of the colored ink 54 not lying on the resist 50 are infiltrated by the etching medium and can be washed off at the latest with the rinsing of the etched foil. In this case, brushes, high-pressure nozzles, rotating felts and the like can be used to assist the detachment. The etching step creates a design as in Fig. 3 (b) shown, in which the bright colors 54 are arranged accurately with the resist 50.
The inventors have also recognized that in etching processes at elevated temperature from about 50 ° C, in some cases, a complete loss of adhesion of resist coatings occurs, although the resist effect of the formulations per se is very good. At present, this effect is explained so that some resist coatings, although a good barrier to the liquid etching medium, but not sufficient Form barrier to gases and the etching medium, which may contain, for example, water and alcohols, developed at temperatures above 50 ° C already a significant vapor pressure. By taking advantage of this effect can be removed together with the metallization 38 of the film with a suitable choice of the bright colors 54 already surviving by a simple etching process color. The colored ink 54 can be printed both before and after a colorless resist 50. Alternatively, the colored color 54 itself may be a resist, which also results in the desired registration during etching.
In all the variants described, the film 22 can also be provided on one of its sides with a pressure-receiving layer, which can be applied at any time and advantageously in a single-layered or primer fashion. If, in certain applications, there are no particularly high demands on the mutual registration of chromatic colors and metallization, in the case of printing the ink-accepting layer on the film side, motifs in bright colors can be printed under them. On the opposite side, for example, primers and heat sealing lacquers can be printed. As intermediate layers, in particular bright colors, effect colors and fluorescent colors can be provided. The heat sealing lacquers used can also be provided with fluorescent substances.
FIG. 4 illustrates the preparation of a film which can be used as a transfer strip and is well suited for example for paper-film composite substrates and polymer substrates. Regarding Fig. 4 (a) For example, in order to produce a film strip 60, a film is firstly provided which enables a reliable release of the applied layer structure, for example a good quality polyester film 62 without pressure pretreatment. For a uniform, easy-to-print surface The polyester film 62 can be coated with a first uniform layer, for example a UV-crosslinking lacquer layer 64. The desired colored motif print 28 is then with printing inks 26 on the lacquer layer 64 in the principle at Fig. 2 already described type printed.
On the motif print 28 is, also analogous to Fig. 2 , an embossing lacquer layer 30 is printed, and this provided with an embossment 32 which is in register with the colored motif print 28, that is, the partial areas printed with printing inks 26. Registered in the same operation on the embossment 32 complementary, so just in the unembossed areas of the embossing lacquer layer 30, wash 34 printed.
In the next operation, one or more vapor deposition steps are carried out to produce a metallization coating 66, wherein the metallization coating 66 is in the simplest case a metal layer, for example an aluminum layer, optionally with chrome plating, or a chromium-aluminum-chromium structure. The metallization coating 66 may also be a multi-layer structure which, in addition to one or more metal layers, also contains other types of layers, in particular dielectric spacer layers. For example, the multi-layer structure may be a color-shifting thin-film structure (for example with chromium, SiO 2 and aluminum), a gold-blue structure (aluminum, SiO 2 , aluminum), or else a thin-film fixed color consisting of a layer sequence of metal 1, ultrathin dielectric d ≤ 250 nm, metal2. It is understood that the metallization coating 66 can be applied in several sub-steps and that some layers, for example the dielectric layer of a multi-layer structure, can also be printed. After the formation of the metallization coating 66 is in Fig. 4 (a) shown layer sequence before.
Then, a washing step is performed in which the wash paint 34 is removed with the overlying areas of the metallization coating 66. This produces a perfect registration of the remaining regions 68 of the metallization coating 66 with the embossment 32 and with the color regions 26 of the first motif print 28. Subsequently, a pressure of primer layers 70 and heat sealing lacquers 72 can take place, so that the in Fig. 4 (b) results in layer sequence shown. The metallization coating 66 may in particular produce a color shift effect or a fixed color. As a result, a foil strip 60 is obtained in which the color effect of the metallization coating 66 is arranged in register with the colored first motif print 28. The remaining regions 68 of the metallization coating 66 are visible from the upper side of the film strip 60, and the color regions 26 are visible from the underside. The carrier film 62 can be removed again after the layer sequence has been transferred to a target substrate.
FIG. 5 (a) shows a representation like Fig. 4 (a) for a variant in which the metallization coating 66 is formed as a three-layer structure with a first metallization 74, a printed dielectric 76 and a second metallization 78. The dielectric 76 is printed as a motif, wherein the pressure is as complementary as possible to the wash color 34, which can be realized for example via an insetter process. The layer thickness of the dielectric 76 does not have to be constant either, but can be selectively varied locally, as in Fig. 5 (a) illustrated by two different layer thicknesses. In this way, thin-film elements with partially different fixed colors and / or different color-shift effects can be realized. The different layer thicknesses can be achieved, for example, by different cell geometry be realized in gravure printing. Since the pressure of the dielectric 76 also takes place with different layer thicknesses with a single cylinder, the areas of different layer thickness and thus the areas with different color effects are perfectly matched to one another. Subsequently, a second metallization 78 is applied, which may consist of the same or a different metal than the first metallization 74.
In the washing step already described, the washing ink 34 with the regions of the metallization coating 66 arranged above it is then removed and printing of primer layers 70 and heat sealing lacquers 72 takes place, so that the inks Fig. 5 (b) results in layer sequence shown. From the upper side of the film strip 60, the remaining regions 68 of the metallization coating 66 with their partially different color effects produced by the thickness variation of the dielectric layer 76 are visible, from the underside in perfect register to the color regions 26. The carrier film 62 can after transferring the layer sequence be withdrawn to a target substrate again.
Another variant of the method is in Fig. 6 illustrating the production of a film which is to be applied as a film strip 80 on a substrate with a viewing window, wherein the carrier film of the security element is to remain in the product. With reference to the example of Fig. 6 (a) For this purpose, a PET carrier film 22 is provided which has been provided on a print-pretreated side (reference numeral 24) with an embossing lacquer layer 30 with desired embossments 32. Embossed embossing lacquer layer 30 was then metallized with a metal layer 38.
On the resulting layer sequence was then on both sides in Supersimultandruck a customized motif print with first inks 82 and second inks 84 applied, wherein the applied to the metallized side printing inks 82 are formulated as a resist. These resist inks 82 include one or more hues 82A, but may also contain colorless inks 82B that do not self-hue, but serve only as a resist. The inks 84 on the non-metallized side represented one or more different vibrant colors.
Then, an etching step is performed, by which the metal layer 38 is removed on the areas not covered with resist inks 82 (82A, 82B), so that a perfect registration between the remaining areas 86 of the metal layer 38 and the inks 82 (82A, 82B ) of the metallized side (s) 84 of the non-metallized side, as in FIG Fig. 6 (b) shown. The printing inks 82, 84 present on the opposite sides are thus always separated from each other by a matched metal region 86 and can produce metallic glossy appearances of different colors from opposite sides. At the points where the printing ink 82 is not formed by a colored ink 82A but by a colorless resist 82B, the purely metallic appearance of the metal layer 38 is visible from the upper side.
Regarding Fig. 7 Now, the production of a film will be described, which carries two independent metallized imprints, for example, two reflection holograms, which are visible from opposite sides of the film forth. The metallized embossings are matched exactly to each other, at least in some areas, so that when viewed from one side only exactly one motif is visible. To create additional color effects, the metallized imprints are provided with adjusted color-coordinated layers.
As a starting point of the described method is a film structure 100 of in Fig. 7 (a)
with a PET carrier film 22, an embossing lacquer layer 30 applied to a print-pretreated side (24) with desired first embossments 102, a first metallization 104, an intermediate layer 106 optically separating the two embossings with a second embossing 108 and a second metallization 110 Such a film structure can be produced, for example, by a metal transfer process, as described for example in the publications WO 2011/138039 A1
. EP 2 340 175 B1
. EP 2 321 311 B1
or EP 2 874 823 B1
is described. The disclosure of the cited documents is incorporated in the present application in this respect.
In the present case, the film structure of Fig. 7 (a) combined with at least one colored layer, which covers a metallization over part of the surface or over the entire surface, but is to be passaged only in those places where there is already a metallization. Regarding Fig. 7 (b) For this purpose, a photoresist 112, which has been colored in the desired manner, applied to the metallized side of the carrier film 22 in the form of a desired motif. For coloration, the resist 112 can be mixed with soluble dyes, for example dyes from the Orasol or Neozaponreihe, or with color pigments.
After physical drying and optionally rehydration, the resist 112 is exposed from the side opposite the metallizations 104, 110 (reference numeral 114), the metallizations 104, 110 acting as an exposure mask, so that only the areas of the resist arranged in non-metallized subareas of the film structure 112 be exposed sufficiently strong. Particularly advantageous is the exposure with LED spotlights, since with low heat input, the moisture required for this step remains in a higher proportion in the resist layer 112.
Subsequently, the exposed photoresist 112 is removed in a developing solution, so that the in Fig. 7 (c) formed film structure in which the remaining colored resist areas 116 are adapted to the metallized portions 104, 110.
Alternatively, the photoresist 112 can also be applied to the opposite side 124 of the carrier foil 22 from the metallized side, the exposure then taking place from the metallized side, so that the metallizations 104, 110 again act as an exposure mask. The metallized portions 104, 110 and the post-processed resistive resist areas are then on opposite sides of the support film 22.
Of course, it is also possible to provide both sides of the carrier film 22 with additional structured colored layers. For this purpose, for example, based on the design of the Fig. 7 (c) the side 124 of the carrier foil 22 facing away from the metallization 104, 110 is coated with a further colored photoresist 118, as in FIG Fig. 7 (d) shown. The photoresist 118 is exposed from the side of the metallizations 104, 110 (reference numeral 120), so that the metallizations again act as an exposure mask. After removal of the exposed photoresist, the in Fig. 7 (e) illustrated film construction in which the remaining colored resist areas 122 are matched to the metallized portions 104, 110 and to the colored resist areas 116.
When patterning the second photoresist 118, it is to be avoided to wash away the first photoresist 116 post-exposed by the exposure step 120. For this purpose, for example, instead of an immersion step, a one-sided coating of the film with developer solution and appropriate washing done. Another possibility is to re-illuminate the photoresist 116 by exposure to a UV emitter, which also causes a significant heat input and thus to reduce its solubility. In another possible approach, the photoresist 116 may be exposed by appropriate metering at the exposure step 120 to dry to such an extent that it does not become soluble upon exposure while the photoresist 118, being shielded by the intervening layer structure, becomes soluble. This effect can be assisted by the choice of pigmentation of the two photoresist layers 116, 118.
The one-sided or two-sided slide assemblies of FIGS. 7 (c) or 7 (e) can be provided in the usual way with ink-receiving layers and heat-sealing lacquers or otherwise processed further.
FIG. 8 illustrates further manufacturing variants of film security elements that are to be applied over a see-through window and in which the carrier film of the security element should remain in the product.
Regarding Fig. 8 (a) For example, to produce a film security element 130, a carrier film 22 having an embossing lacquer layer 30 and an embossed embossed structure 32 is provided. A wash ink 132 in the form of a desired motif is printed on embossed embossing lacquer layer 30, and a colored photoresist 134 is applied to the side of support film 22 opposite embossing lacquer layer 30. The wash color 132 contains as Filler, for example, between 1% and 30% titanium dioxide and may contain other UV absorbers.
Now the photoresist 134 is exposed from the side of the carrier foil 22 provided with the wash ink 132 (reference numeral 136), the motif formed by the wash ink 132 acting as an exposure mask. Then, the photoresist 134 is developed, depending on the type of photoresist 134 used either the exposed areas 138 remain standing, as in the variant of Fig. 8 (b) shown (negative resist), or the unexposed areas 140 remain standing, as in the variant of Fig. 8 (d) shown (positive resist).
The provided with the wash ink 132 side of the carrier film 22 is provided after the exposure of the photoresist 134 at any time with a desired coating, for example, coated with metals and / or other layers or vapor-deposited. The wash ink is then removed in a washing process with the overlying parts of the coating. The result is a film security element 130, in which the areas 142 of the coating remaining after the washing step are arranged precisely matching the remaining areas 138 and 140, respectively, of the photoresist 134. In the variant with negative resist, the remaining coating areas 142 are congruent with the remaining photoresist areas 138, as in FIG Fig. 8 (c) while in the positive resist variant the remaining coating regions 142 and the remaining photoresist regions 138 are arranged complementary to one another, as in FIG Fig. 8 (e) shown.
In the Fig. 8 described use of positive or negative resist can also be applied to the other, described in this application designs with photoresist so that each left resist areas can be generated, which are congruent with the structures used as an exposure mask, or which are complementary to the structures used as an exposure mask.
FIG. 9 describes an embodiment in which a film security element 150 is provided by means of a transfer process with a structured colored layer. Regarding Fig. 9 (a) a carrier foil 22 is provided which is provided on one side with an embossing lacquer layer 30 with an embossed structure 32 and a structured metallization 152. The formation of the structured metallization 152 can be effected, for example, by means of a washing process or a resist-based etching process, as already described above several times. A colored photoresist 154 is applied to the side of the carrier foil 22 opposite the metallization 152 and converted into a soluble form by exposure 156 from the metallized side of the carrier foil 22. The structured metallization 152 acts as an exposure mask.
The photoresist 154 is developed and patterned so that the remaining areas 158 of the photoresist are aligned with the patterned metallization 152, as in FIG Fig. 9 (b) shown. The photoresist 154 is chosen so that it becomes tacky under pressure and / or temperature influence and can accept color 160 in different ways. For example, by printing on a suitable ink ribbon, it is possible to achieve that ink 160 is preferably transferred to resist 158 and not to embossing lacquer 30, as in FIG Fig. 9 (c) shown. Even when brought into contact with pigments, which are present, for example, dry or as a suspension in a suitable solvent, it can be achieved that the pigments remain only superficially on the embossing lacquer 30 and can later be easily washed off while adhering to the tacky photoresist 158 stick and not be replaced by the washing step. The bringing into contact can be done with a conventional printing process, such as gravure or flexographic printing and also in motif form.
LIST OF REFERENCE NUMBERS
As a result, a film security element 150 is produced by such a transfer method, in which the resist areas 158 coated with ink 160 are arranged precisely matching the structured metallization 152. The further processing of the element can take place in the manner already described above.
- film strips
- through opening
- film strip
- polyester film
- pretreated area
- printing inks
- first colored motif print
- Embossing lacquer layer
- washable ink
- printing inks
- metal layer
- second colored motif print
- remaining areas of the metal layer
- remaining areas of the second motif print
- 45A, 45B, 45C
- different passages
- second colored motif print
- second bright colors
- film strips
- polyester film
- UV-curing lacquer coating
- metallization coating
- remaining areas of the metallization coating
- primer layers
- Heat seal lacquers
- first metallization
- printed dielectric
- second metallization
- film strips
- first inks
- chromatic colors
- colorless printing inks
- second inks
- remaining areas of the metal layer
- film structure
- first imprints
- first metallization
- second coinage
- second metallization
- remaining colored resist areas
- remaining colored resist areas
- opposite side of the carrier film
- Foil security element
- washable ink
- colored photoresist
- remaining resist areas
- remaining resist areas
- remaining areas of the coating
- Foil security element
- structured metallization
- colored photoresist
- remaining resist areas