NL2004018C2 - SAFETY FEATURE. - Google Patents

Description

P30131NLOO / JV

Short description: Safety feature

The invention relates inter alia to the use of a specific type of security feature, the security feature itself, an item provided with a security feature and a method for authenticating an item provided with a security feature.

The use of a security feature in articles, such as paper including synthetic "paper" mainly made of plastic and documents produced therefrom such as banknotes and the like, is known in the art. To protect such papers produced therefrom, many security methods and materials are known to prevent easy counterfeiting. The protection, hereinafter referred to as safety feature 10, can be provided in the substrate during production. In the case of a paper substrate, a security paper is then created. The best known example of such a safety feature applied during production is the watermark. Luminescent fibers and security threads in banknotes are also generally known to the general public. One or more safety features can also be added to that substrate after the production of a substrate, such as paper, for instance with the aid of a special printing technique or by applying an optically active element such as a hologram or a kinegram. The nature of the substrate is then less relevant. In both cases, i.e. both when ordinary paper and security paper are used - as a substrate - a document is obtained which comprises one or more security features. Safety paper differs from paper that is otherwise protected because a security feature is included in the paper mass during production.

For the general public to recognize the authenticity (authentication) of an object, such as a security document or security document, it is dependent on sensory perception such as viewing with the eyes and touching with the fingers, thereby often detecting the presence of a security feature and / or the position to determine thereof.

Security features that are eligible for this include, among other things, in addition to the security threads and watermarks mentioned above, also an optically active structure / print which exhibits an angle-dependent image / color such as a holographic structure on the front of euro banknotes or an angle-dependent color on the back thereof. The sense of touch can be used to feel a "ripple structure" in the striped rectangular trapezoid above the printed architectural structure on the front of a euro note with the fingers and / or nails.

A next step in the detection of a safety feature is that one uses simple and inexpensive tools such as a UV lamp, polarizer, -2-conductivity meter and the like. This type of aid is used, for example, when checking the authenticity of a banknote during a checkout transaction in a store. These safety features, which can be detected with simple tools, are also referred to as second-line features.

5 Moreover, security features are still present in banknotes, the existence of which is only known to the competent authorities or persons such as banks and / or central banks, and for which specific and sometimes complex detection equipment is required to prove their presence. Here one speaks of third and fourth line characteristics. Finally, there is a fifth level which, for example, forensic experts use, as described in EP 1 902 855 A2.

To guarantee the authenticity of a document, in particular identity documents such as passports, use is increasingly made of a transponder, which is included in the document, including data from the rightful owner. The use of a transponder is sometimes problematic with certain objects, such as, for example, in banknotes. This is caused by the costs and vulnerability in view of the usual way of handling such objects.

Many security features from the second level are based on specific properties of chemical compounds. Some examples of patent publications describing certain properties of compounds for use in securing security and / or value documents include: luminescence via excitation by electric current (WO 2004 108426 A2) or by shape change (WO 01 83237 A1); magnetic behavior (EP 1 646 057 A2, EP 1 646 056 A1) and electrical conductivity (US 2006 0075249 A1).

With luminescent features, the most frequent use is excitation by light. The luminescent properties are usually selected in the visible or near IR region. In this context, connections, materials and configurations are searched for that ultimately yield specific luminescent properties and characteristics, such as described in DE 10 2006 047 851 A1, DE 10 2006 047 852 A1, US 2007 0132984 A1, US 2007 0187630 A1 and EP 1 801 759 A1.

Specific fibers, films, security threads and inks are, in addition to the paper itself, often the direct carriers of the security features. Often different safety features are combined in one and the same support, such as for example a security thread, such as materials that exhibit fluorescence and magnetism. This often means that there are a number of safety features that are spread spatially in / on the carrier. Safety features can also be incorporated into inks and then delivered to the substrate. When successively applying inks with different safety features, it is difficult but possible to do so in register, so that several, different safety features can be detected at one position. It is also possible to incorporate different security features in one and the same ink, so that registering it is easier. It is then desirable that the nature of the compounds comprising the safety features allows a stable mixture to form. The use of different compounds as safety features whose chemical dissolution behavior is less compatible can complicate the formation of a stable mixture, even with the risk of separation during or after application.

In DE10 2005 047 609 A1, the problem of registering various safety features / properties has been attempted to be solved by making particles with a core-shell structure in which the core has properties other than the shell.

The invention has for its object to reduce or to avoid one or more of the disadvantages of the above-mentioned prior art and / or to offer a usable alternative.

More in particular, it is an object of the invention to provide a safety feature and application with which it is possible to position different safety features / security properties on a molecular scale relative to each other.

A further object is to provide a compound as a safety feature with a specific mutual molecular orientation of the active (detectable) group or groups.

Yet another purpose is to achieve an efficient and / or specific intramolecular interaction between different active groups or compounds such as, for example, between luminescent compounds.

Yet another object is to provide a compound in which different functional groups with different properties are combined into a macromolecule.

Yet another object is to provide a security feature that can unite all security levels within a molecule ranging from the first visible level to machine-readable signals for the forensic level.

According to a first aspect of the invention, one or more objects are achieved by applying a security feature according to claim 1.

The following terms are used within the scope of the invention.

A functional group is a compound present on the polyisocyanide support structure, preferably peptide polyisocyanide support structure with a visually observable property and / or a measurable property. Examples of -4 properties include color, luminescence, (para) magnetism and electrical conduction. Biological functional groups can also be used such as, for example, nucleic acid fragments, proteins, peptides or nucleotides.

The term support structure is used in the context of the present application to denote both a polyisocyanide support structure and a peptide polyisocyanide support structure.

A reactive group is a group on the polyisocyanide support structure or the peptide portion or on the functional group which makes it possible to link a functional group to the support structure, for example a mono- and / or a di-peptide polyisocyanide support structure. Acetylene and azide groups are examples of such reactive groups.

Luminescence is understood to mean the emission of electromagnetic radiation after excitation. Both fluorescence and phosphorescence fall under this concept.

The lifespan of the excited state is understood to mean the average lifespan of the excited state. This service life is inversely proportional to the decay rate of the excited state.

The safety feature according to the invention comprises a support structure, namely a polyisocyanide support structure, preferably a chiral peptide polyisocyanide structure, which as support for coupling one or more functional groups, whether or not of different nature, and therefore whether or not with separately visually observable or properties to be detected. Many functional groups can be linked to one and the same polymer molecule. Because functional groups are present on the chiral support in a spatially very specific manner relative to each other, very specific and unique intramolecular interactions between the different linked functional groups and / or chiral support structure are possible. This has the consequence that the response of the safety characteristic to, for example, electromagnetic radiation clearly deviates from that of a safety characteristic in which the functional group as such, i.e. without the specific intramolecular interactions, is present.

It is also possible to link many different types of functional groups with distinct functionality to the same carrier structure, usually the same polymeric carrier molecule. This makes it possible, after functionalization, to observe one and the same support structure separately and / or to give properties to be detected, such as color, luminescence; (para) magnetic behavior and, for example, conduction.

Furthermore, it is possible to make mixtures of different types of functionalized support structures which exhibit identical or highly similar dissolution behavior because the molecules have a similar basic structure and can in addition be provided with specific groups which influence dissolution behavior, whereby undesired demixing during application is no longer a problem.

The support structure can be functionalized with only one type of functional group. It is also possible for different functional groups to be present on one and the same polymeric molecule, as a result of which the functionalized polymer exhibits a combination of entirely different properties such as, for example, both luminescence and (para) magnetism, a color and conductivity or different colors, for example a color in the visible. area and an absorption in the near infrared. Interactions between different types of functional groups may also occur, as a result of which the behavior of the functional groups with regard to detection is modified with, for example, electromagnetic radiation and a unique signal can be detected that cannot be imitated by mixing the individual functional groups because in in that case the unique spatial positions and thus the specific intramolecular interactions of the functional groups with respect to each other are missing.

Since the support structure has a helix configuration, in addition to all signals from the functional groups, the skeleton structure will display a CD (circular dichroism) signal to be detected. Also, due to the chirality of the skeletal structure, the signal of a functional group can also be polarized, such as, for example, a polarized luminescence.

Furthermore, it is possible to adjust the solubility of the functionalized polymer by giving at least a portion of the side chains of the polymer a character adapted to a desired environment / solvent by means of additional groups. In order to achieve the correct solubility in an aqueous environment, the functionalized polymer is also provided with hydrophilic groups, for example ethylene glycol or cellulose side groups. This makes it possible to use the connections directly in the (paper) manufacturing process. If one wants to incorporate the functionalized compound in a plastic, a more non-polar character is required, which can be adjusted on the basis of non-polar side chains and / or additional groups to be provided.

A film can be produced from such a plastic, which film can then be used in the form of a so-called film strip, and a patch or thread in or on the paper. This foil 30 can then also be processed so that it also has other properties which are caused by this specific treatment. Safety fibers with many properties can also be made from a plastic containing functionalized compounds which can then, for example, be incorporated into the paper mass.

The solubility behavior adjustable by suitable functional groups is also of great importance if the compounds are to be used as safety features in inks or pigments.

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A further advantage of the functionalized support structure is that it can be entirely organic compounds, which is an advantage for use in safety inks.

The polyisocyanide support structure can be prepared by means of Ni (11) -5 catalyzed polymerization starting from isocyanide monomer, such as tert-butyl isocyanide. The voluminous alkyl groups thereby ensure stabilization of the helix formed. Functionalized polyisocyanides that provide a detectable paramagnetic signal are described, for example, in Vlietstra, E. J .; Nolte, R.J. M .; Zwikker, J. W .; Drenth, W .; Meijer, E.W., Synthesis and magnetic properties of a rigid high-spin density polymer with 10 piperidine N-oxyl pending groups, Macromolecules, 1990, 23, (4), 946-948 and Abdelkader, M .; Drenth, W .; Meijer, E.W., Synthesis and characterization of a stable poly (iminomethylene) with pendant phenoxyl radicals, Chem. Mater. 1991, 3, (4), 598-602.

The presence of peptide side chains gives a more stable helix with greater stiffness due to the H-bridge interactions between the peptide side chains. The preparation of peptide polyisocyanides is described, for example, in Cornelissen, J. J. L. M .; Graswinckel, W. S .; Adams, P.J. H. M .; Nightingale, G. H .; Kentgens, A. P. M .; Sommerdijk, N. A. J. M .; Nolte, R.J. M. Synthesis and characterization of polyisocyanides derived from alanine and glycine dipeptides. J. Polym. Sci., Part A: Polym. Chem. 2001, 39, (24), 4255-4264, Cornelissen, J. J. L. M .; Donners, J. J. J. M .; de Gelder, R .; Graswinckel, W. S .; Mason, G. A .; Rowan, A. E .; Sommerdijk, N. A .; Nolte, R.J.M. beta -Helicalpolymers from isocyanopeptides. Science 2001, 293, (5530), 676-680 and the thesis “Polymerization of Isocyanopeptides” from Metselaar, G.A., 2006 (ISBN 90-9020135-1). In Cornelissen, JJLM Hierarchical transfer or stereochemical information in synthetic macromolecules, Pure Appi Chem., 2002, 74, (11), 2021-2030, Scheme 1 shows a large number of synthesized isocyanopeptide-based polymers based on relatively simple amino acids such as alanine, glycine, serine and histidine.

Examples of reactive groups, in particular an acetylene group or an azide group are described in Schwartz, E .; Kitto, H. J .; de Gelder, R .; Nolte, R.J. M .;

Rowan, A. E .; Cornelissen, J. J. L. M. Synthesis, characterization and chiropticalproperties or 30 clickable polyisocyanopeptides. J. Mater. Chem. 2007.17, (19), 1876-1884, and Schwartz, E .; Koepf, M .; Kitto, H. J .; Espelt, M .; Nebot-Carda, V. J .; De Gelder, R .; Nolte, R.

J. M .; Cornelissen, J. J. L. M .; Rowan, A.E. Water-soluble azido polyisocyanopeptides as functional (3-sheet mimics. J. Polym. Sci., Part A: Polym. Chem. 2009, 47, 4150-4164.

Linking a functional group via a reactive group to the peptide polyisocyanide support structure is described, for example, in Rostovtsev, V. V .; Green, L. G .; Fokin, V. V .; Sharpless, K. B. A stepwise House cycloaddition process: Copper (l) -catalyzed -7- region-selective "ligation" or azides and terminal aikynes. Angew. Chem. Int. Ed. 2002, 41, (14), 2596-2599.

The functional groups can be selected from the group comprising luminescent chromophores, compounds with (para) magnetic or electromagnetic properties, compounds with an absorption spectrum in the UV region and / or the visible region and / or the (near) IR region, electrical conductivity exhibiting compounds, optionally via mutual orientation, biochemical compounds, compounds that also impart a liquid crystal behavior to the safety feature and combinations thereof.

In one embodiment, the functional group is a luminescent chromophore. Examples which may be mentioned include thiophene, coumarin, perylene and porphyrin. See Kitto, H. J .; Schwartz, E .; Nijemeisland, M .; Koepf, M .; Cornelissen, J .; Rowan, A. E .; Nolte, R.J.M., Post-modification of helical dipeptido polyisocyanides using the 'click' reaction. J. Mater. Chem. 2008, 18, (46), 5615-5624.

According to a special embodiment, the chromophore coupled to the support structure 15 exhibits, by intramolecular interaction of the linked groups, luminescence characteristics that differ from the luminescence characteristics of the same non-linked groups. According to a further embodiment thereof, the emission spectra and / or lifetime of the excited state of the luminescence as a result of intramolecular interactions between at least one type of functional groups differ from the emission spectra and / or lifetime of the (monomeric units) of the relevant monomeric units. type of functional groups.

According to a particularly preferred embodiment, at least two different types of luminescent chromophores are coupled to the (peptide) polyisocyanide support structure, the emission spectrum of one type of luminescent chromophore showing overlap with the excitation spectrum of another type of luminescent chromophore. Examples of such a combination are, for example, platinum porphyrin with perylene, and coumarin with perylene. Kitto et al., Supra.

According to a special embodiment, at least a paramagnetic functionality is coupled to the support structure, such as, for example, a porphyrin, such as for a peptide polyisocyanide support structure described by Witte, P. A. J .; Castriciano, M .; Cornelissen, J. J. L. M .; Scolaro, L. M .; Nolte, R.J. M .; Rowan, A.E. Helical polymer-anchored porphyrin nanorods. Chem. EUR. J. 2003, 9, (8), 1775-1781, containing a metal ion with unpaired spider incorporated therein. See also Vlietstra, supra and Abdelkader, supra.

In a special embodiment, at least two different functional groups with different electromagnetic properties are connected to the support structure.

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Perylene (diimide) is an example of a group for an electrically conductive functionalized polymer. See Schwartz, E .; Palermo, V .; Finlayson, C. E .; Huang, Y.-S .; Otten, M. B. J .; Liscio, A .; Trapani, S .; Gonzalez-Valls, I .; Brocorens, P .; Cornelissen, J. J. L. M .; Peneva, K .; Müllen, K .; Spano, F .; Yartsev, A .; Westenhoff, S .; Friend, R. H .; Beljonne, 5 D .; Nolte, R.J. M .; Samori, P .; Rowan, A. E. "Helter Skelter-like" Perylene Polyisocyanopeptides. Chem. EUR. J. 2009, 15, 2536-2547.

In a further embodiment of the use according to the invention, at least one functional group is a biochemical compound, for example selected from the group of nucleic acid fragments, protein structures, peptides and smaller biochemical compounds such as, for example, the nucleotides thymine and adenine as described in; Otten, M. B. J. PhD thesis: Functionalized Polyisocyanides. Radboud University, Nijmegen, Netherlands, ISBN: 978-90-9024890-5

According to yet another embodiment, the safety feature exhibits a liquid crystal behavior, for example, nematic or cholesteric behavior. See Metselaar, G. A .; Wezenberg, S. J .; Cornelissen, J. J. L. M .; Nolte, R. M .; Rowan, A.E. Lyotropic liquid-crystalline behavior or polyisocyanodipeptides. J. Polym. Sci., Part A: Polym. Chem. 2007, 45, (6), 981-988.

According to a particularly preferred embodiment, the security feature has a solubility adapted to the matrix in which it is incorporated or processed. An example of a group that gives hydrophilic behavior is an alcohol, such as ethylene glycol. As described above, non-polar functional groups can be used to easily incorporate the safety feature into a plastic.

Use of the security feature preferably takes place in items selected from the group comprising security papers, security papers, security papers, identity papers, security papers, vouchers, admission tickets, labels, labels, prescription forms, certificates, and packages.

According to a further aspect, the invention relates to an object, preferably selected from the group comprising security paper, security paper, security documents, identity documents and security documents, vouchers, admission tickets, labels, labels, prescription forms, certificates and packaging, which have at least one security feature comprises a polyisocyanide support structure, advantageously a peptide polyisocyanide support structure, which is provided with at least one functional group.

According to yet another aspect, the invention relates to a safety feature comprising a polyisocyanide support structure, preferably peptide polyisocyanide support structure provided with at least one functional group.

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Furthermore, the invention according to yet another aspect relates to a method for authenticating objects provided with a security feature according to the invention, wherein a property dependent on a functional group is determined, for example via sensory perception, and preferably a machine-detectable, more 5 preferably measurable property. In a special embodiment thereof, the chirality of a polyisocyanide support structure, advantageously a peptide polyisocyanide support structure provided with at least one functional group, is additionally determined.

The above-described preferred embodiments of the use of a security feature according to the first aspect apply correspondingly to these aspects of the invention.

The invention will be explained below with reference to the appended drawing, in which

FIG. 1 is a schematic representation of a configuration of a peptide polyisocyanide support structure with reactive groups; FIG. 2 a) - e) are schematic representations of various possibilities of functionalization of the peptide polyisocyanide support structure;

FIG. 3a) -d) is a schematic representation of a chromophore-functionalized peptide polyisocyanide support structure with associated spectra; and

FIG. 4a) -c) is a schematic representation of a peptide polyisocyanide support structure functionalized with two chromophores with associated spectra.

Figure 1 shows a schematic representation of the structure of a basic molecule. It consists of polymerized isocyanide with alanine side chains. The amino acid side chains result in a stabilized helix structure via beta-type H-bridge interactions, the helix of which, for example, is left or right-handed, depending on the stereo-specific configuration of the amino acid side chains. This basic structure exhibits great stability, the length of which can vary from 100 nm to about 20 µm, which corresponds to a mole. mass from 6,105 to 1,108 gmol'1 (Cornelissen, JJLM; Donners, JJJM ,; de Gelder, R .; Graswinckel, WS; Metselaar, GA; Rowan, AE; Sommerdijk, NAJM; Nolte, RJM, Science 2001,293 (5530 676-680 The terminal amino acid 30 comprises a reactive group represented by X, with which functional groups are suspended from the polyisocyanide support structure.

Another method for preparing a polymer with a functional groups is by modifying the functional group such that the functionalized polymer is formed by polymerization.

Figure 2 schematically illustrates the flexibility of the peptide polyisocyanide support structure for obtaining a functionalized polymer. The functional group itself comprises a reactive group that is capable of reacting with the reactive group X.

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Figure 2a shows a schematic example in which a polyisocyanide peptide is functionalized with one type of functional group, shown here as A.

Figure 2b gives an example of a polyisocyanide peptide which, divided into blocks, contains different functional groups represented here as group A and group B, respectively.

Figure 2c gives a schematic example of a polyisocyanide peptide on which, in random order, two functional groups are present, viz. Group A and group B.

Figure 2d shows a polyisocyanide peptide with functional groups A and B in an alternating order.

Figure 2e gives an example of a carrier molecule functionalized with groups A and B, to which a hydrophilic additional group represented by a gray-colored circle is linked at different positions, so that the molecule is soluble in an aqueous medium.

Figure 2 shows only two different types of functional groups, but it will be clear that many more different groups may be present

Figure 3 shows a schematic example of a molecule that contains one luminescent chromophore as a functional group, namely perylene diimide (A). The degree of utilization with a functional group in this example is 100% (compare Figure 2a).

The spectral data of this compound and of the uncoupled units are given in figures 3b-d. The black lines in this figure indicate the functionalized molecule (the polymer); the gray lines of non-coupled units (the monomer)

It is immediately noticeable that the spectral properties of the functionalized polymer differ from those of the monomeric constituents. The differences in UV-vis absorption (Figure 3b), in emissions (Figure 3c) and circular medicalism (CD, Figure 3d) in particular fall. In the UV-fishing range, it is clear that the spectrum of the polymer is widened and shifted to longer wavelengths relative to the uncoupled units. This can also be seen in the fluorescence emission spectrum, where the spectrum of the polymer has even shifted tens of nanometers and moreover has a different intensity. A clear signal can be seen in the CD spectrum of the polymer in the perylene chromophore region, in contrast to the non-coupled units where no signal is present in this region.

Figure 4 shows a schematic example of a molecule that is functionalized with two different chromophores, namely perylene diimide (black, Figure 4a) (A) and coumarin (gray in Figure 4a) (B). Figure 4a is a schematic representation of the functionalized polymer; the occupancy of the polymer with 50% A and B is random; Figure 4b shows the UV-vis absorption spectrum and the emission spectrum of the constituent monomer groups. Both the uv-vis absorption spectrum and the fluorescence spectrum of the functionalized molecule show the presence of both chromophores, ie perylene (between 450-600 nm) and coumarin (between 300-400 nm). When comparing the fluorescence spectrum of the molecule that is functionalized with both perylene and coumarin (Figure 4c, gray lines) with the fluorescence spectrum of a molecule that is only functionalized with coumarin (as schematically in Figure 2a) (Figure 4c, black line) , then it is seen that the fluorescence of the coumarin is clearly shifted to shorter wavelengths in the first case and that there is therefore a specific interaction between these two chromophores.

The abovementioned examples refer to the degree of utilization of the polymer, that is to say that a certain percentage of all terminal amino acids is occupied with a functionality. One can arbitrarily choose this percentage when synthesizing the compounds. A difference in percentage has a direct influence on the intensity of a signal and on the degree of intramolecular interactions.

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Claims (23)

Use of a polyisocyanide support structure provided with at least one functional group as a safety feature. 2. Use according to claim 1, wherein the polyisocyanide support structure is a peptide polyisocyanide support structure. Use according to claim 1 or 2, wherein the functional group has a sensory perceptible property and / or a physically detectable property. Use according to claim 3, wherein the functional group is selected from the group comprising luminescent chromophores, compounds with (para) magnetic or electromagnetic properties, compounds with an absorption spectrum in the UV region and / or the visible region and / or the IR region. or near IR region, compounds that exhibit electrical conductivity, biochemical compounds, compounds that also impart a liquid crystal behavior to the safety feature and combinations thereof. 5. The use according to claim 4, wherein the functional group is a luminescent chromophore which, by intramolecular interaction of the linked groups, has luminescence characteristics that differ from the luminescence characteristics of the same non-linked groups. 6. The use according to claim 5, wherein the emission spectra and / or lifetime of the luminescence as a result of the intramolecular interactions between at least one type of functional groups deviate from the emission spectra and / or lifetime of the excited state of the monomeric units of the relevant units. type of functional groups. 7. Use according to claim 4, wherein the functional group comprises at least two different types of luminescent chromophores, wherein the emission spectrum of one type of luminescent chromophor exhibits overlap with the excitation spectrum of another type of luminescent chromophore. The use according to any of the preceding claims, wherein a functional group exhibits emission in the visible region. - 13- The use according to any of the preceding claims 1-7, wherein a functional group exhibits emission in the non-visible region. 10. The use as claimed in claim 1, wherein the functional structure-provided support structure exhibits electrical conductivity due to the specific mutual orientation of the functional groups. 11. Use according to claim 4, wherein the biochemical compound is selected from the group of nucleic acid fragments, protein structures, peptides and nucleotides. The use according to claim 4, wherein at least two different functional groups with different electromagnetic properties are connected to the support structure. The use according to any of the preceding claims, wherein the security feature exhibits a liquid crystal behavior. The use according to claim 13, wherein the security feature exhibits a nematic behavior. 20 The use of claim 13, wherein the security feature exhibits cholesteric behavior. 16. Use as claimed in any of the foregoing claims, wherein the carrier structure is provided with an additional group for solubilizing the safety feature in an aqueous environment. 17. Use as claimed in any of the foregoing claims 1-15, wherein the support structure is provided with an additional group for solubilizing the safety feature in an apolar environment The use according to any of the preceding claims, wherein the security feature is contained in an ink or in a pigment. Use according to any one of the preceding claims in articles selected from the group comprising security papers, security papers, security papers, identity papers, security documents, vouchers, admission tickets, labels, labels, prescription forms, certificates, and packages. 20. Object selected from the group consisting of security paper, security paper, security documents, identity documents, value documents, vouchers, admission tickets, labels, labels, prescription forms, certificates and packaging, comprising at least one security feature that has a polyisocyanide support structure, preferably a peptide polyisocyanide support structure which is provided with at least one functional group. 10 A security feature comprising a polyisocyanide support structure, preferably a peptide polyisocyanide support structure, provided with at least one functional group. 22. Method for authenticating objects provided with a security feature according to claim 20, wherein a property dependent on the functional group is determined. The method of claim 22, wherein the chirality of a peptide polyisocyanide support structure provided with at least one functional group is determined. 20