SECURITY INK AND SECURITY ITEM, SUCH AS A BANKNOTE, WITH A TRILUMINESCENT EFFECT.

Abstract

A security ink contains at least a first fluorescent and phosphorescent pigment and a second fluorescent pigment, wherein the security ink, if excited with a first wavelength, emits radiation with a first emission spectrum, if excited with a second wavelength, emits radiation with a second emission spectrum that is different from the first emission spectrum, and after the excitation has ended, emits radiation with a third emission spectrum that is different from the first emission spectrum and that is different from the second emission spectrum.

Description

The present invention relates to a triluminescent security ink, to a security article, such as a banknote, comprising this security ink as one or more security features, and to a method for evaluating the authenticity of a security document comprising a security article. Security items, such as banknotes, bank cards, credit cards, driver's licenses, and the like, must incorporate one or more security features so that any expert can reliably determine whether they are genuine or counterfeit. This is a prerequisite for enabling a recipient of a banknote, such as a cashier at a supermarket, to decide whether to accept it. It also allows bank employees to assess the authenticity of banknotes before loading them into an ATM or transferring them to the teller. Furthermore, the existence of such security features prevents, or at least significantly hinders, unauthorized individuals from copying or redesigning the respective item.On the other hand, security features even allow an ATM or banknote counting machine to ensure that banknotes are correctly aligned during their transport through the machine, which is a prerequisite for reliably counting the number of banknotes. Various sensor systems are known for detecting fluorescence effects, most of which are based on a UV excitation source and an imaging camera or photodiode that detects and verifies the emission of visible light, as described in CA 2 349 681 A1. Particularly valuable security items, such as banknotes, are required to have several different security features, and it is preferred that they have as many different security features as possible. Examples of security features include security images, which comprise an image that is otherwise invisible or undetectable under ambient conditions, but which becomes visible or detectable after the application of, for example, UV radiation. Alternatively, the image on a banknote or credit card may have a first color under ambient conditions, which changes to a second color that is different from the first color after the application of, for example, UV radiation. In particular, UV fluorescence has long been widely used as a Level 2 security feature on banknotes, identity documents, revenue stamps, and other valuable documents such as train, subway, or bus tickets. Typically, security features are created for this purpose using interacting fluorescent elements, for example, within a symbol or element, as described in EP 1 567 358 A1 and EP 3 621 821 A1, or using fine-line graphic elements, also called guilloche lines, with a fluorescent color transition visible only under ultraviolet light, such as those created by rainbow printing. Verification of the presence of this security feature is usually carried out using a UV lamp with a conventional wavelength of, for example, 365 nm.However, these security features are relatively easy to counterfeit, because a wide variety of fluorescent markers, highlighters, and fineliners are readily available on the market, which can be used to produce counterfeit banknotes or identity documents. Even complex graphic designs using two or more different fluorescent inks make counterfeit banknote production not impossible, but simply more difficult, if a printing press is available. Standard organic and inorganic UV fluorescent pigments generally exhibit a broad emission peak. The trend toward combining these broadband emitters with specialized narrowband emitters contributes to increased security but also necessitates expensive, high-resolution verification tools. The use of chemically and physically more stable inorganic UV fluorescent pigments for security printing applications entails stringent requirements regarding pigment size and hardness. Depending on the printing technology employed, pigment sizes as small as 1 to 3 micrometers are required, particularly for lithographic printing. Intaglio and screen printing allow for pigment sizes up to 10 micrometers. Organic pigments have the disadvantage of low chemical and physical stability, including poor lightfastness and resistance to solvents, acids, and bases. bRcrnn / rznz / e / γΐΛΐ A common method for creating different emission wavelengths in a security item, particularly a banknote or identity document, is to dope individual inks with different UV-fluorescent pigments that exhibit different emissions and print the different inks on top of each other. However, this has the disadvantage that overprinting different doped inks leads to a reduction in the emission intensity of the underlying inks due to the overprinted layer. The use of biluminescence effects has also been proposed in the field of security printing. This involves pigment mixtures that can be excited at two different wavelengths and that exhibit distinct emission characteristics at each excitation wavelength, preferably displaying a different color at each. However, these emissions are generally too weak to achieve a readily recognizable effect and are sometimes difficult to produce due to the high pigment load required for a noticeable bicolor effect. It has also been suggested that a core-shell pigment be used for this purpose, in which each of the two parts of the core-shell pigment emits visible light at a different wavelength after excitation.However, these core-shell pigments have several disadvantages, such as the complexity of pigment production and the fact that the shell's absorbency reduces the visible light generated in the pigment core. Furthermore, some of the excitation light from the core is absorbed by the surrounding shell material. Additionally, the safety of safety devices using such biluminescence effects still needs improvement. In view of this, the underlying object of the present invention is to provide a security ink that is particularly suitable for use in preparing a security article, such as a printed security paper, such as a banknote or a verification certificate, having an enhanced level of protection against counterfeiting, which does not require multi-layer systems, in which an upper layer reduces the effects of a lower layer, but which can nevertheless be easily assessed as genuine or counterfeit. According to the present invention, this objective is achieved by providing a security ink containing at least a first fluorescent and phosphorescent pigment (preferably inorganic) and a second fluorescent pigment (preferably inorganic), wherein the security ink, (in particular if printed on a substrate) if excited with a first wavelength emits radiation with a first emission spectrum, if excited with a second wavelength, emits radiation with a second emission spectrum that is different from the first emission spectrum, and after the excitation has ended, emits radiation with a third emission spectrum that is different from the first emission spectrum and that is different from the second emission spectrum. This security ink leads to a security item with a significantly improved level of protection against counterfeiting because it possesses at least triluminescent properties, which are very difficult to copy. The security ink itself, as well as any security ink printed on a substrate as a security feature, exhibits these properties, although they may be attenuated in the security ink due to the solvent it contains. When excited with a first wavelength, the security element emits radiation with a first emission spectrum. It then emits radiation with a second emission spectrum, different from the first, when excited with a second wavelength. Once the excitation is complete, it emits, for a certain period of time, radiation with a third emission spectrum, also different from the first and second.For example, the three emission spectra cover at least portions of the visible light range, so the safety feature exhibits at least a triple color-changing effect. For instance, the safety feature is red when excited with a first wavelength, yellow when excited with a second wavelength, and green for a certain period of time after both excitations have ceased. If the safety feature is excited simultaneously with both excitation wavelengths, it is orange, as it is a mixture of red and yellow. Another feature of the present invention is the combination of fluorescent and phosphorescent effects; that is, effects with different decay times are used. This is due to the different mechanisms of these two types of luminescence.According to the present invention, phosphorescence is an emission of radiation, and preferably a light emission, that persists for more than 0.1 s after the termination of excitation and can preferably be perceived by the human eye if the emission spectrum bRcrnn / rznz / e / Ywi is at least partially in the visible region. In contrast, fluorescence, according to the present invention, involves the emission of radiation, and preferably light emission, during excitation with decay times τι / e of less than 25 ms. Therefore, the emission of radiation, according to the present invention, is fluorescence when less than 2% of the emission intensity is present after 0.1 s following the termination of excitation, compared to the excitation at 0.0 s, i.e., the time point of excitation termination. This corresponds, according to the function ea, to τι / e 25 ms.In contrast, the radiation emission according to the present invention is phosphorescence, where at least 15% of the emission intensity is present 0.1 s after the excitation terminates, compared to the excitation intensity at 0.0 s, i.e., the point at which the excitation terminates. The combination of fluorescent and phosphorescent effects allows the security features to display a third color after both excitations have ended, a color that becomes progressively fainter over time. Another important advantage of the security ink of the present invention is that the pigments can be combined into a single security ink; that is, the security feature produced with the security ink only requires one printed layer of the ink.In this way, the aforementioned problems that arise when different inks are printed on top of each other—such as an upper layer reducing the effects of a lower layer or shadowing effects, respectively—are reliably avoided. Furthermore, using only one security ink for a security feature on a security item simplifies the printing process and increases flexibility compared to using different printing inks layered on top of each other. Despite these advantages and the drastically improved level of protection against counterfeiting, the security item containing the security ink can be easily, quickly, and reliably assessed as genuine or counterfeit. If inorganic pigments are used, the security ink of the present invention has the additional advantage of being very stable, because inorganic pigments are chemically and physically stable, particularly against solvents, acids and bases, and have low lightfastness. To achieve the aforementioned effects, it is preferred that the first pigment of the security ink according to the present invention have a first fluorescence excitation spectrum with at least one peak and a first phosphorescence excitation spectrum with at least one peak, and that the second pigment have a second fluorescence excitation spectrum with at least one peak, wherein the highest peak of the first fluorescence excitation spectrum is at a different wavelength than the highest peak of the second fluorescence excitation spectrum. This ensures that the first and second pigments are not simultaneously excited at their optimum wavelengths.On the other hand, that is, when the fluorescence excitation spectra of both pigments are not sufficiently displaced from each other, a first mixture color is obtained with the excitation at the first wavelength and a second mixture color is obtained with the excitation at the second wavelength, where both mixture colors are different from each other, since the at least two fluorescence excitation spectra are different from each other. The more the fluorescence excitation spectra of the two pigments are offset from each other, the easier it is to individually excite only one, or at least predominantly only one, of the two pigments at a first excitation wavelength and to individually excite the other, or at least predominantly the other, of the two pigments at a second excitation wavelength. In view of this, it is preferred that the highest peak of the first fluorescence excitation spectrum be offset relative to the highest peak of the second fluorescence excitation spectrum by at least 10 nm, preferably by at least 20 nm, more preferably by at least 30 nm, even more preferably by at least 40 nm, still more preferably by at least 50 nm, even more preferably by at least 70 nm, and most preferably by at least 100 nm.In particular, good results are obtained when the highest peak of all the peaks in the first fluorescence excitation spectrum is shifted relative to the highest peak of all the peaks in the second fluorescence excitation spectrum from 10 to 400 nm, preferably from 20 to 300 nm, more preferably from 30 to 200 nm, and much more preferably from 40 to 140 nm. Preferably, the first pigment as well as the second pigment are each an inorganic pigment. bRcrnn / rznz / e / γΐΛΐ In a further development of the idea of ​​the present invention, it is proposed that the phosphorescence of the first inorganic pigment be excited by the first wavelength or by the second wavelength, i.e., that the first phosphorescence excitation spectrum overlaps at least partially with the first fluorescence excitation spectrum and / or with the second fluorescence excitation spectrum. In this way, only two different excitation wavelengths need to be used to exploit all the optical effects, i.e., the emission of at least two different fluorescence emission spectra at two different excitation wavelengths and at least one different phosphorescence emission spectrum after the excitation is terminated. According to an alternative embodiment of the present invention, the first phosphor excitation spectrum does not overlap at all or only to a negligible degree with the first fluorescence excitation spectrum and with the second fluorescence excitation spectrum. In this embodiment, additional excitation at a third wavelength is required to excite the phosphor effect. In principle, pigments can have excitation wavelengths across the entire electromagnetic spectrum. For example, pigments can independently have excitation wavelengths in the X-ray, ultraviolet, visible light, or infrared ranges. However, as explained below, it is preferred that the fluorescence and phosphorescence emission of pigments be in the visible light range. Therefore, it is preferred that pigments independently have excitation wavelengths with a frequency higher than that of visible light, such as in the X-ray or UV range. More preferably, each of the first fluorescence excitation spectrum, the second fluorescence excitation spectrum, and the first phosphorescence excitation spectrum has at least one peak with a crest in the ultraviolet range.Most preferably, each of the first fluorescence excitation spectrum, the second fluorescence excitation spectrum, and the first phosphorescence excitation spectrum have at least one peak that has a crest at a wavelength between 220 and 380. To be usable with conventional security feature detection systems, since they are installed in handling systems, such as ATMs, payment machines, bank sorters and identity document verification systems, which use detection wavelengths of 254 nm and / or 312 nm and / or 365 nm, it is suggested in a further development of the idea of ​​the present invention that one of the first fluorescence excitation spectrum and the second fluorescence excitation spectrum have high excitation at one or two of the wavelengths of 254 nm, 312 nm and 365 nm and low excitation at the rest of these wavelengths, while the other of the first fluorescence excitation spectrum and the second fluorescence excitation spectrum have high excitation at at least one of the remaining wavelengths and low excitation at one or two of the wavelengths.where the other excitation spectrum has high excitation. Preferably, high excitation means that the emission obtained by excitation of the respective pigment at one or two of the wavelengths of 254 nm, 312 nm, and 365 nm is at least 15%, preferably at least 20%, more preferably at least 25%, and most preferably more than 30% higher than the emission obtained by excitation (which is therefore called low excitation) of the same pigment at the remaining wavelengths. In this way, one, or at least predominantly one, of the fluorescences of the first and second pigments is excited to a greater extent at the conventional wavelengths, while the other is excited at this wavelength only to a lesser degree or to a negligible degree, respectively. The first phosphor excitation spectrum may have high excitation at one, two, or all of the wavelengths of 254 nm (UV-C), 312 nm (UV-B), and 365 nm (UV-A). Preferably, the first phosphor excitation spectrum has high excitation at at least one of these wavelengths: 254 nm, 312 nm, and 365 nm. In particular, it is preferred that the first phosphor excitation spectrum have high excitation at at least one of these wavelengths, at which one of the first fluorescence excitation spectra and one of the second fluorescence excitation spectra also have high excitation. In this embodiment, the phosphor is excited in conjunction with the excitation of one of the fluorescences, such that only two different excitation wavelengths are required to assess the authenticity of the security feature made of the security ink.Alternatively, it is possible that each of the first phosphorescence excitation spectrum, the first fluorescence excitation spectrum, and the second fluorescence excitation spectrum exhibits high excitation only at one of the wavelengths of 254 nm, 312 nm, and 365 nm, wherein the wavelengths at which the first phosphorescence excitation spectrum, the first fluorescence excitation spectrum, and the second fluorescence excitation spectrum exhibit high excitation are different from each other. In this embodiment, phosphorescence occurs at different wavelengths, such that a total of three different excitation wavelengths are required to assess the authenticity of the security feature made of the security ink. To easily distinguish the fluorescence emissions of the first pigment and the second pigment, it is preferred that the first pigment have a first fluorescence emission spectrum with at least one peak and a first phosphorescence emission spectrum with at least one peak, and the second pigment have a second fluorescence emission spectrum with at least one peak, wherein the highest peak of all the peaks in the first fluorescence emission spectrum is at a different wavelength than the highest peak of all the peaks in the second fluorescence emission spectrum. In particular, good results are obtained in this respect when the highest peak of all the peaks in the first fluorescence emission spectrum is offset relative to the highest peak of all the peaks in the second fluorescence emission spectrum by at least 10 nm, preferably by at least 20 nm, more preferably by at least 40 nm, even more preferably by at least 60 nm, even more preferably by at least 100 nm, and much more preferably by at least 150 nm. The highest peak in the first phosphor emission spectrum may be the same as one of the highest peaks in either the first or second fluorescence emission spectrum. In this case, after both excitations are quenched, a phosphor afterglow is present with a color identical to, or at least very similar to, that of the first or second fluorescence. Alternatively, the highest peak in the first phosphor emission spectrum may differ from the two highest peaks in both the first and second fluorescence emission spectra. In this case, after both excitations are quenched, a phosphor afterglow is present with a color different from both the first and second fluorescence. As previously stated, in the present invention it is particularly preferred that the fluorescence and phosphorescence of at least the first and second pigment are visible in different colors, such that a first color change occurs if the first excitation wavelength is replaced by the second excitation wavelength and a second color change occurs when both excitations end.In view of this, it is suggested in a further development of the idea of ​​the present invention that the first fluorescence emission spectrum, the second fluorescence emission spectrum, and the first phosphorescence emission spectrum each have at least one peak that is at least partially in the visible light range, and preferably each have at least one peak that has a crest in the visible light range, so that the security ink (particularly if printed on a substrate), if excited with a first wavelength, emits radiation with a first color; if excited with a second wavelength, it emits radiation with a second color that is different from the first color; and after the excitation has ended, it emits radiation with a third color that is preferably different from the first color and different from the second color. In addition to the color-changing effects mentioned above, a feature of the present invention is that, once the excitation is complete, the first pigment emits phosphorescent radiation, which by definition has a much longer decay time than fluorescence radiation. Therefore, after the termination of each excitation, the first fluorescence emission, as well as the second fluorescence emission, ends extremely quickly, while the first phosphorescent emission continues even after the excitations cease and becomes less intense until it, too, ends.Preferably, the decay times with respect to the present invention of the fluorescence of the first pigment and the fluorescence of the second pigment are independently less than 1 ms and more preferably less than 1 ms, while the decay time of the phosphorescence of the first pigment persists for more than 0.1 seconds and preferably for more than 60 min. In accordance with a further development of the idea of ​​the present invention, the security ink according to the present invention contains at least one additional pigment, wherein the at least one additional pigment is an inorganic fluorescent pigment, an inorganic phosphorescent pigment, or an inorganic fluorescent and phosphorescent pigment. In this embodiment, even more complex emission effects can be achieved, such as four, five, or even more color changes at a respective number of different excitation wavelengths. For example, the security ink may contain a third inorganic fluorescent pigment having a fourth excitation spectrum and a fourth fluorescence emission spectrum, wherein the fourth excitation spectrum and the fourth fluorescence emission spectrum are different from the first-to-third excitation spectra and the first-to-third emission spectra.Alternatively, the second fluorescent pigment can be an inorganic fluorescent and phosphorescent pigment having a fourth excitation spectrum and a fourth phosphorescent emission spectrum, wherein the fourth excitation spectrum and the fourth fluorescence emission spectrum are different from the first to third excitation spectra and the first to third emission spectra. According to a further particular preferred embodiment of the present invention, the security ink according to the present invention may contain at least one other pigment, wherein the at least one additional pigment is neither a fluorescent pigment nor a phosphorescent pigment and preferably is not a luminescent pigment, i.e., it is not chemiluminescent or the like. The at least one additional pigment in this embodiment may be an organic or inorganic pigment. In particular, it is preferable to add an additional pigment that is not a luminescent pigment and has an emission spectrum identical or so similar to the fluorescence emission spectrum of one of the first and second pigments that one of the first and second pigments is masked when excited. Most preferably, the additional pigment, which is a non-luminescent pigment, emits radiation in the visible light range and emits a color that is identical or very similar to the fluorescence color emitted by the first pigment when excited. In this embodiment, the fluorescence of the first pigment, when excited, is masked by the additional pigment, which is a non-luminescent pigment, producing a camouflage effect.When the first excitation wavelength is switched off and the second excitation wavelength is irradiated onto the security ink, security feature, and security article, respectively, the second fluorescence color is visible as long as the second excitation wavelength is irradiated onto the security ink, security feature, and security article, respectively. When the second excitation also ends, the third phosphorescence color becomes visible, becoming fainter and fainter until it disappears after a few seconds or minutes, depending on its decay time. The masking of the pigments (preferably inorganic) can be further improved by adding a matting agent or by using optically variable transparent pigments with a color change, such as pearlescent pigments, for example.They are marketed by Merck KGaA under the Iriodin® brand. Pearlescent pigments can also be used to enhance the luminescence effect and add color and brilliance to the ink. Similarly, colored pigments can be added to give the ink a body color. According to a further particular preferred embodiment of the present invention, the security ink according to the present invention contains no pigment other than a luminescent pigment. Preferably, in this embodiment, the first and second pigments are body-colored, so that the security ink is, without excitation, colorless and, for example, a colorless ink for lithography, intaglio and / or screen printing, numbering ink, or a banknote varnish. In particular, good results are obtained when the first pigment is selected from the group consisting of: AEAI2O4: Eu2+(Dy3+, Ho3+, Nd3+), Zn(S,O):(Cu, Ag), AE4Ali4O25:Eu2+, Dy3+, AE2MgSi2O7:Eu2+(Dy3+,Ho3+, Nd3+) and AE2SiO4:Eu2+(Dy3+,Ho3+, Nd3+). AE is the abbreviation for selected alkaline earth metal ions from the group consisting of Ca, Ba, and Sr ions and means that one of the Ca, Ba, and Sr ions, a combination of two of the Ca, Ba, and Sr ions, or all three Ca, Ba, and Sr ions are present. The metals mentioned after the colon mean dopant metals, where one or more of the dopant metals mentioned in parentheses may be present, with the dopant metal(s) not mentioned in parentheses being obligatory. For example, AEAI2O4: Eu2+(Dy3+, Ho3+, Nd3+) means that AEAI2O4 is doped with Eu2+ and with one, two, or three of Dy3+, Ho3+, and Nd3+. Preferably, the content of the dopant component Eu2+, Dy3+, Ho3+, Nd3+, Cu and Ag in the above formulas are, independently of each other, from 0.01 to 10% by moles, more preferably from 0.01 to 5% by moles, even more preferably from 0.1 to 3% by moles. In particular, good results are obtained when the first pigment is selected from the group consisting of: AEAI2O4:Eu2+(Dy3+, Ho3+, Nd3+), Zn(S,O): (Cu, Ag) and AE4Ali4O25:Eu2+, Dy3+. Again, the content of the doping components Eu2+, Dy3+, Ho3+, Nd3+, Cu and Ag in the above formulas are, independently of each other, preferably from 0.01 to 10 mol%, more preferably from 0.01 to 5 mol%, and even more preferably from 0.1 to 3 mol%. Most preferably, the first pigment of the security ink according to the present invention is SrAl2CU:Eu2+, Dy3+, wherein the Eu content is preferably from 0.1 to 10 mol%, more preferably from 0.1 to 5 mol%, even more preferably from 1 to 3 mol% and most preferably from 1, 2 or 3 mol% and wherein the Dy content is preferably from 0.01 to 10 mol%, more preferably from 0.01 to 3 mol% and most preferably from 0.1 to 1 mol%. The inorganic compounds suitable for the second pigment are pigments selected from the group consisting of: Ln2O3:Do, Ln2O2S:Do, LnBO3:Do, LnPO4:Do, LnVO4:Do, Ln3AlsOi2:Do, Ln3GasOi2:Do, Ln2SiOs:Do, Ln2Si2O?:Do, LnVC>4:Do in each of which Ln is selected from Se, Y, La, Gd and Lu and Do is selected from Pr, Sm, Eu, Tb, Tm and Cr, Ln2Me3Oi2:Do with Ln and Do defined as above and with Me selected from Mo and W, M2LnMe2Os:Do with Ln, Me and Do defined as above and with M selected from Li, Na, K, Rb and Cs, Y2O2S:Do with Do defined as above, AE2S¡C>4:Eu, Mg2S¡O4:Eu, bRcrnn / rznz / e / γΐΛΐ ZnS:DP with DP selected from Cu, Ag, and Au, LnMgAlnOi9:Eu with Ln selected between La and Gd and LnMgAlnOi9:Eu, Mn with Ln selected between La and Gd. Preferably, the content of the doping component Do, Eu or DP in the above formulas are, independently of each other, from 0.01 to 10% by moles, more preferably from 0.01 to 5% by moles, even more preferably from 0.1 to 3% by moles. In particular, good results are obtained when the second pigment is selected from the group consisting of Ln2O2S:Do, ZnS:DP, LnMgAlnOi9:Eu, LnMgAlnOi9:Eu, Mn, LnVO4:Do, and Y2O2S:Do. Again, the content of the doping component Do, Eu, or DP in the above formulas is, independently of each other, preferably from 0.01 to 10 mol%, more preferably from 0.01 to 5 mol%, and even more preferably from 0.1 to 3 mol%. Most preferably, the second pigment of the security ink according to the present invention is Y2O2S:Eu, wherein the Eu content is preferably from 0.1 to 30 mol%, more preferably from 0.1 to 10 mol%, even more preferably from 2 to 8 mol%, and most preferably from 3.5 or 7.5 mol%. Each of the first pigment and the second pigment preferably has, independently of each other, an average particle size, dso particle size, respectively, of 1 to 10 pm or 1 to 3 pm, depending on the type of printing technology with which the security ink is applied to the substrate of the security article. To ensure homogeneous distribution of the first and second pigments within the printing ink, including the binder and other components, it is preferable to moisten the first pigment powder, which has an average particle size of less than 0.5 to 10 µm, for example, by dispensing using a dispenser. If necessary, the pigments should then be deagglomerated by breaking up any agglomerates in the binder into single-pigment particles. Suitable wetting agents are available, for example, from Evonik and BYK-Chemie GmbH under the registered trademarks Surfynol®, Tegopren®, Anti-Terra, Byk, and Disperbyk. A preliminary check of the homogeneity and continuous distribution of the pigment extraction can be performed and analyzed using a defined layer thickness and pigment content (bRcrnn / rznz / e / YiAi) in relation to the particle size and layer homogeneity.Clouds or spots indicate the separation of the ink compounds, an incomplete mixture, or the formation of pigment aggregates in groups, respectively, which can be solved by additional process optimization work. To achieve the aforementioned effects and, in particular, the color changes with a sufficiently high intensity, it is proposed in a further development of the idea of ​​the present invention that the content of each of the first and second pigments be independently of each other from 10 to 90% by weight and preferably from 40 to 60% by weight based on the total pigment content. In particular, the total content, i.e., the sum of the content of the first pigment, the second pigment, and any other optional pigments, is preferably 1 to 80% by weight, preferably 5 to 70% by weight, more preferably 10 to 60% by weight, and most preferably 20 to 40% by weight of the total pigment based on the overall composition of the security ink. The content of each of the first pigment, the second pigment, and any other optional pigments is preferably 4 to 54% by weight and more preferably 8 to 24% by weight of the total pigment based on the overall composition of the security ink. The present invention is not limited in particular with regard to the printing technique by which the security ink is applied to the substrate to form the security article. In particular, the security printing ink may be formulated as a printing ink selected from the group consisting of lithographic inks, intaglio inks, die-cutting inks, flexographic inks, and screen-printing inks. In addition to pigments, the security ink according to the present invention includes one or more binders, wherein the binder or binders are selected from the group consisting of polyesters, polyethers, polyurethanes, polyamides, polyacrylates, maleinate resins, rosin resins, ketone resins, alkyd resins, rosin-modified phenolic resins, hydrocarbon resins, silicates, silicones, silanes, phenolic resins, urea resins, melamine resins, polyterpene resins, polyvinyl alcohols, polyvinyl acetates, polyvinyl chloride, polyvinyl ethers, polyvinyl propionates, polymethacrylates, polystyrenes, polyolefins, coumarone-indene resins, aromatic formaldehyde resins, acid carbamide resins, resins of sulfonamide, chlorinated bRcrnn / rznz / e / γΐΛΐ resins, nitrocellulose, CAB (cellulose acetate butyrate), CAP (cellulose acetate propionate), cellulose compounds, rubbers,radiation-cured resins and arbitrary combinations of two or more of the aforementioned binders. According to a particular preferred embodiment of the present invention, the security ink comprises: (i) 5 to 50% by weight and preferably 10 to 30% by weight of the sum of the first pigment, the second pigment and other optional pigments, wherein the total content of fluorescent pigments and fluorescent and phosphorescent pigments is 5 to 50% by weight and preferably 10 to 30% by weight, (ii) 10 to 40% by weight and preferably 20 to 30% by weight of one or more binders, (iii) 20 to 60% by weight and preferably 30 to 40% by weight of one or more solvents, wherein the solvent is preferably selected from the group of vegetable oils and arbitrary combinations of two or more of the aforementioned solvents, and (iv) optionally, 1 to 10% by weight of one or more additives selected from those belonging to the group consisting of rheological additives, adhesives, defoamers, additives of slip, anti-corrosion additives, gloss additives, waxes, wetting agents, curing agents, chelating agents, photoinitiators,Inhibitors, desiccants, stabilizers, emulsifiers, pH adjusting additives, abrasion resistance additives, plasticizers, antistatic additives, preservatives, light protection agents, mattifying agents, and arbitrary combinations of two or more of the aforementioned additives. A suitable lithographic ink may comprise: bRcrnn / rznz / e / γΐΛΐ The sum of all fluorescents, as well as fluorescent and phosphorescent pigments: Colored pigment: Burden: Alkyd resin: Vegetable oil: 20-60% by weight 0-20% by weight 0-5% by weight 15-20% by weight 5-15% by weight Phenol-modified rosin resin: 10-20% by weight Wax: 0.5-5% by weight Hydroquinone stabilizer: 0-1.5% by weight Oxidative drying agent: 1-2% by weight Luminescent pigments are available through Leuchtstoffwerk Breitungen GmbH and can be mixed according to the desired effect. Suitable colored pigments are available through BASF SE, through Clariant Plastics & Coatings Ltd., through Heubach GmbH and through Ferro Performance Pigments, SL. Pigments in the form of titanium dioxide can be procured through The Chemours Company TT, LLC, through The Kerala Minerals & Metals Ltd. and through Shandong Doguide Group Co., Ltd. bRcrnn / rznz / e / γΐΛΐ Suitable loads are available, for example, through Evonik Industries AG, Krahn Chemie GmbH, BCD Chemie GmbH, Omya AG, Bassermann minerals GmbH & Co. KG, BYK-Chemie GmbH, Elementis pie and Solvay GmbH. Alkyd resins can be purchased, for example, through Lawter, Inc., Allnex Resins Germany GmbH, Synthopol Chemie Germany and Dr. rer. pol. Koch GmbH & Co. KG. Suitable vegetable oils include, for example, calendula, canola, castor, Chinese wood, coconut, cottonseed, dried castor, flaxseed, grapeseed, linseed, palm, palm kernel, peanut, rapeseed, oiticica, safflower, soybean, sunflower, resin and tung oils supplied, for example, by Alberdingk Boley GmbH and Mercur Handel GmbH. Eligible phenol-modified rosin resins are available, for example, through Lawter, Inc., Respol Resinas, SA and Euro-Yser - Produtos Químicos, SA Lithographic inks may also contain waxes and stabilizers. Suitable suppliers of waxes include, for example, Euroceras Sp. z oo, Eastman Chemical Company, and Clariant Plastics & Coatings Ltd. Stabilizers are obtained from Eastman Chemical Company, Ratnagiri Chemicals Pvt. Ltd., and Merck KGaA. Oxidative drying agents, such as metal carboxylates or metal soaps of, for example, cobalt, manganese, iron, vanadium, lead, zirconium, lithium or strontium, cerium, aluminum, potassium, calcium, barium or zinc, are available, for example, through OMG Borchers GmbH. A suitable UV-curing water-based screen printing ink may comprise: The sum of all fluorescent lights, like this bRcrnn / rznz / e / Ywi as fluorescent and phosphorescent pigments: 10-30% by weight Pearlescent pigments: Urethane acrylate dispersion: 6-15% by weight 60-80% by weight Wetting additive: 0.1-2.5% by weight Substrate wetting additive: 0.1-2.5% by weight Defoamer: 0.1-2.5% by weight Photoinitiator: 2-10% by weight Luminescent pigments are available from Leuchtstoffwerk Breitungen GmbH and can be mixed to achieve the desired effect. Pearlescent pigments are available from suppliers such as Merck KGaA, Geotech International BV, and Eckart GmbH. Suitable urethane acrylate dispersions are available, for example, through Sartomer Europa - Arkema, Allnex Resins Germany GmbH or Alberdingk Boley GmbH. Suitable wetting agents are available, for example, through Evonik Industries AG, BYK-Chemie GmbH, Münzing Chemie GmbH and Elementis pie. Suitable defoamers for water-based formulations are available, for example, through Evonik Industries AG, BYK-Chemie GmbH, Münzing Chemie GmbH and Elementis pie. Suitable photoinitiators for radical curing systems are supplied, for example, through IGM Resins BV or Lambson Ltd. A suitable cationic radiation-cured screen printing ink may comprise: The sum of all fluorescents, as well as fluorescent and phosphorescent pigments: Pearlescent pigments: Cycloaliphatic epoxy resin: 10-30% by weight 0-25% by weight 60-80% by weight Pyrogenic silica: Defoamer: Photosensitizer: Photoinitiator: 0.5-10% by weight 0.1-5% by weight 0.1-2% by weight 2-10 wt% bRcrnn / rznz / e / γΐΛΐ Luminescent pigments are available from Leuchtstoffwerk Breitungen GmbH and can be mixed to achieve the desired effect. Pearlescent pigments are available from suppliers such as Merck KGaA, Geotech International BV, and Eckart GmbH. Cycloaliphatic epoxy resins are available, for example, through Dow Chemical Company, Gabriel Chemical, or IGM Resins BV. Pyrogenic silica is supplied, for example, through Evonik Industries AG and Orisil Ltd. Defoamers are available, for example, through Evonik Industries AG and BYK-Chemie GmbH. Photosensitizers are supplied, for example, through Lambson Ltd, IGM Resins BV, Merk KGaA and TCI Deutschland GmbH. Suitable photoinitiators are available, for example, through Dow Chemical Company, Lambson Ltd, IGM Resins BV and BASF SE. A suitable intaglio ink may comprise: The sum of all fluorescent, fluorescent, and phosphorescent pigments: Colored pigment Burden 5-30% by weight 0-10% by weight 20-60% by weight Alkyd resin 5-30% by weight Vegetable oil 5-25% by weight Phenol-modified rosin 5-10% by weight Wax 3-15% by weight Dryer Thinner 0.1-2.5% by weight 1-10% by weight Luminescent pigments are available through Leuchtstoffwerk Breitungen GmbH and can be mixed according to the desired effect. Suitable colored pigments are available, e.g., through BASF SE, Clariant Plastics & Coatings Ltd, Heubach GmbH and Ferro Performance Pigments, SL. Pigments in the form of titanium dioxide are available, for example, through The Chemours Company TT, LLC, The Kerala Minerals & Metals Ltd. and Shandong Doguide Group Co., Ltd. Suitable loads are available, for example, through Evonik Industries AG, Krahn Chemie GmbH, BCD Chemie GmbH, Omya AG, Bassermann minerals GmbH & Co. KG, BYK-Chemie GmbH, Elementis pie and Solvay GmbH. Alkyd resins can be purchased, for example, through Lawter, Inc., Allnex Resins Germany GmbH and Synthopol Chemie - Dr. rer. pol. Koch GmbH & Co. KG. Suitable vegetable oils include, for example, calendula, canola, castor, China wood, coconut, cottonseed, dried castor, flaxseed, grapeseed, linseed, palm, palm kernel, peanut, rapeseed, o'iticica, safflower, soybean, sunflower, resin and tung oils supplied, for example, by Alberdingk Boley GmbH and Mercur Handel GmbH. Eligible phenol-modified rosin resins are available, for example, through Lawter, Inc., Respol Resinas, SA, Arizona Chemical Ltd., and Euro-Yser - Produtos Químicos, SA Intaglio inks may also contain waxes and stabilizers. Suitable wax suppliers include, for example, euroceras Sp. z oo, Clariant Plastics & Coatings Ltd, and BYK-Chemie GmbH. Oxidative dryers, such as metal carboxylates or metal soaps of, for example, cobalt, manganese, iron, vanadium, lead, zirconium, lithium or strontium, cene, aluminum, potassium, calcium, barium or zinc, are available, for example, through OMG Borchers GmbH. Suitable thinners or dethickeners are available, for example, through Shell Global Solutions International BV, Total SA and Alberdingk Boley GmbH. The effect pigment can also be incorporated into UV-cured numbering inks. These numbering inks can be printed using a letterpress process, for example, on a KBA-Giori Super Numerota® printing press. The basic color formulation is similar to that of UV-cured lithographic inks; however, the rheological adjustment is slightly different, and the layer thickness is greater (e.g., 4 g / m² versus approximately 1 g / m² for lithography). The other components are preferably those mentioned above bRcrnn / rznz / e / YiAi for the composition of lithographic security ink. Another aspect of the present invention is a safety article, comprising: i) a substrate, iii) optionally one or more layers of printing ink and iii) the aforementioned security ink, which is applied over at least a portion of at least one surface of the substrate or over the top layer of one or more optional layers of printing ink. Security ink is applied to a portion of a substrate surface or to the top layer of one or more optional layers of printing ink, for example, in the form of a line, a dot, a halftone, or a pattern. The present invention is not particularly restricted as to the type of substrate. Suitable examples of the substrate are, in particular, paper, a polymer sheet, or a composite material comprising at least one layer of paper and at least one polymer sheet. The security article may be selected in particular from the group consisting of security papers, polycarbonate sheets, polyethylene terephthalate sheets, composite materials of a lower security paper and an upper polymer sheet, composite materials of a lower polymer sheet and an upper security paper, composite materials of a lower security paper, an intermediate polymer sheet and an upper security paper, composite materials of a lower polymer sheet, an intermediate security paper and an upper polymer sheet, and hybrids of a security paper, in which part of the security paper is replaced by a polymer sheet. Preferably, the security ink has been applied to the substrate of the security article using a printing technique selected from the group consisting of lithographic inks, intaglio inks, die-cutting inks, flexographic inks, and screen printing inks. The thickness of the security ink depends on the application or printing technique. Therefore, the thickness of the second ink can be 1 to 3 microns for lithograph printing ink, 1 to 10 microns for intaglio or gravure printing ink, 1 to 8 microns for flexographic printing ink, and 1 to 10 microns for screen printing ink. bRcrnn / rznz / e / Ywi To achieve the aforementioned camouflage effect, one or more layers of printing ink may be placed between the substrate and the security ink, wherein at least one of the one or more layers of printing ink may contain at least one pigment having an emission spectrum identical or so similar to the emission spectrum of one of the first and second pigments contained in the security ink that one of the first pigment and the second pigment is hidden when excited, wherein the at least one pigment is preferably a non-fluorescent pigment and a non-phosphorescent pigment. According to an alternative embodiment of the present invention, one or more layers of printing ink can be arranged between the substrate and the security ink, wherein at least one of the one or more layers of printing ink can contain at least one pigment with a bifluorescent effect, wherein preferably this pigment emits in the first excitation wavelength radiation in the visible light range observable by a human being as a first color and emits in the second excitation wavelength radiation in the visible light range observable by a human being as a second color, wherein the first and second colors are different from each other.In this embodiment, the so-called vario effect is obtained; that is, not only does the security ink with at least the first fluorescent and phosphorescent pigment and the second fluorescent inorganic pigment exhibit a color change at different excitation wavelengths, but also a sublayer of the security article. For example, both fluorescence emission spectra of the bifluorescent pigment in the sublayer may differ from the emission spectra of the at least first fluorescent and phosphorescent pigment and the second fluorescent inorganic pigment of the security ink. However, it is also possible that one of the two fluorescence emission spectra of the bifluorescent pigment may be identical to one of the emission spectra of the at least first fluorescent and phosphorescent pigment and the second fluorescent inorganic pigment of the security ink, while the other may be different. The present invention is suitable for any security article. By way of example only, the security article may be selected from the group consisting of banknotes, checks, bank and credit cards, check cards, passports, chip cards, driver's licenses, verification certificates, access tickets, stamps, train and airline tickets, telephone cards, and seals. In accordance with a further aspect, the present invention relates to a method for preparing the aforementioned safety article, comprising the following steps: a) provide a substrate, b) optionally apply one or more layers of printing ink onto the substrate and c) apply the aforementioned security ink on at least part of at least one substrate surface or on the topmost layer of one or more optional layers of printing ink. Another aspect of the present invention is a method for evaluating the authenticity of a security document comprising the aforementioned security article, wherein the method comprises the steps of: i) irradiating the security article with a first wavelength, wherein the first wavelength is capable of exciting the first pigment of the security ink, and determining whether fluorescence radiation is emitted from the security ink, and, if so, characterizing the fluorescence radiation, i) terminating the irradiation with the first wavelength, ii) irradiating the security article with a second wavelength, wherein the second wavelength is capable of exciting the second pigment of the security ink, and determining whether fluorescence radiation is emitted from the security ink, and, if so, characterizing the fluorescence radiation, and iv) terminating the irradiation with the second wavelength, and (v) determine whether phosphorescent radiation is emitted from the security ink when the security article is not irradiated with either the first or second wavelength, and, if so, characterize the phosphorescent radiation. Steps i) av) can be performed in the order i), iii), iii), iv) and v), in the order i), iii), ii), iv) and v) or in the order i), iii), ii) and iv) simultaneously and then v). The characterization of fluorescence radiation and phosphorescence radiation in steps i), ii), and v) can be performed by visually determining the fluorescence radiation or phosphorescence color, determining laboratory values ​​of fluorescence radiation or phosphorescence color bRcrnn / rznz / e / YiAi, or recording a spectrum of fluorescence radiation or phosphorescence color, or by any other suitable method. The present invention is subsequently described by means of examples, but these examples are not limiting. Examples Example 1 Emission measurements in pigments and ink examples The paper prints were prepared by various printing methods using the corresponding security inks, all with a pigment mixture LP-H99V-04-00 from Leuchtstoffwerk Breitungen GmbH as used in Examples 2 to 5 below, which is a pigment mixture containing a first inorganic pigment showing a first fluorescence spectrum and a first phosphorescence spectrum selected from the group of first pigments mentioned above and a second inorganic pigment showing a second fluorescence spectrum selected from the group of second pigments mentioned above. The emission color at different excitation wavelengths was determined by taking emission spectra at excitation wavelengths of 312 nm and 365 nm, respectively, using a fluorescence spectrometer (Edinburgh Instruments FLS920). The parameters for recording the emission spectra of the print samples were: FLS920 with front sample holder, mode: emission scan, excitation: Xe-lamp (dual monochromator, 300 nm grid on); Aexc= 312 and 365 nm, Iris 99 Excitation bandwidth: 2 nm Filter: Excitation: UG11; Emission: GG420 Emission bandwidth: 1 nm Emission area: 400 to 900 / 1 nm Dwell time: 0.05 s Repetitions: 1 Reference correction: active Emission correction: active As shown in Table 1 below, all paper prints exhibited the described effect of changing the emission color at two different excitation wavelengths. The emission colors are expressed by the x,y coordinates of the CIE 1931 chromaticity diagram and verbally by the name of the corresponding color gamut. Table 1: Color change effect observed in paper prints caused by fluorescence at different excitation wavelengths and phosphorescence, expressed by emission color coordinates in the CIE 1931 bRcrnn / rznz / e / YiAi chromaticity diagram and its verbal description Print Name Pigment Mixture Conc. Fluorescence Excitation 312 nm Fluorescence Excitation 365 nm Phosphorescence Excitation Stopped CIE-X CIEy Name CIE-X CIE-y Name CIE-X CIEy Name Intaglio Printing Inks TRL20 20 0.53 9 0.38 1 Red-orange 0.35 3 0.42 6 Yellow-green 0.23 7 0.56 3 Yellow-green TRL21 25 0.54 4 0.38 3 Red-orange 0.36 2 0.43 7 Yellow-green 0.23 9 0.56 4 Yellow-green TRL22 30 0.54 9 0.38 4 Red-orange 0.36 7 0.44 4 Yellow-green 0.23 1 0.56 8 Yellowish green Lithographic printing inks TRL157 45 0.53 1 0.36 7 Reddish orange 0.33 7 0.39 1 Whitish 0.23 7 0.54 5 Yellowish green TRL156 50 0.53 4 0.37 2 Reddish orange 0.34 6 0.40 2 Whitish 0.23 7 0.55 3 Yellowish green TRL170 55 0.54 6 0.36 8 Reddish orange 0.35 0 0.39 6 Whitish 0.23 7 0.54 8 Yellowish green Water-based screen printing inks TRL44 20 0.56 0 0.39 1 orange 0.39 5 0.48 3 Yellow green 0.22 7 0.55 8 Yellowish green to Water-based screen printing inks with pearlescent pigments (Colorstream T10-04), TRL45 20 0.55 7 0.39 5 Orange 0.39 5 0.48 9 Yellow-green 0.23 3 0.56 2 Yellow-green Water-based screen printing inks with pearlescent pigments (Colorstream T10-03) TRL46 20 0.55 2 0.39 7 Orange 0.39 2 0.49 2 Yellow-green 0.22 8 0.55 8 Yellow-green Cationic screen printing inks TRL47 20 0.47 9 0.35 7 Pink-yellow 0.35 5 0.42 7 Yellow-green 0.23 2 0.55 7 Yellow-green Example 2 Lithographic security ink and security article formed with it bRcrnn / rznz / e / γΐΛΐ A printing ink has been prepared with the following composition. Material Trade Name Content [% by weight] Supplier First and second pigment mixture LP-H99V-04-00 40 Leuchtstoffwerk Breitungen GmbH Ti-Pure colored pigment TS-4657 5 The Chemours Company TT, LLC Bentone® filler 38 2 Elementis pie Setalin V 454 E alkyd resin 8.5 Lawter, Inc. Alberdingk refined linseed oil vegetable oil 27.5 Alberdingk Boley GmbH, Phenol-modified rosin resin R 4189 13 Respol Resinas, SA Ceraleno 1X 2 euroceras Sp. z oo wax Hydroquinone stabilizer Mono-tert-butylhydroquinone (MTBHQ) 0.4 Eastman Chemical Company Borchers Dry 0246 oxidative drying agent 1.6 OMG Borchers GmbH Manufacturing process First, a varnish was prepared. Phenol-modified rosin and vegetable oil were heated until a homogeneous mixture was formed. Afterward, the varnish was mixed with the other ingredients listed in the table, except for the oxidative drying agent. The resulting paste was ground in a three-roll laboratory mill. Finally, the oxidative drying agent was added and mixed in. Test methods Test print The ink was applied using a Prüfbau MZ II printability test instrument. Approximately 1.0 g / m² of ink was applied to bleach-free vellum paper (Papierfabrik Louisenthal GmbH; 90 g / m² basis weight). Viscosity The measurement was performed using a Haake RheoStress 6000, supplied by Thermo Scientific, with a 20 mm / 1° conical plate measurement geometry. Pigment particle size measurement Particle size was investigated using an optical microscope (ZEISS 47 30 11-9901). A small amount of the ink sample was applied as a very thin film to a glass plate. The colorless particles were examined under polarized light to enhance the visible contrast between the particles and the medium. The evaluation was performed according to the measurement scale in the eyepiece. Emission measurements The emission maximum was measured using a Shimadzu RF6000 spectrofluorophotometer. The lithographic ink was applied as described above to achieve a basis weight of approximately 1.0 g / m². The measurement range was 200–900 nm, and UV-340 (incident beam; excitation side) and Vis L-42 (outgoing beam; emission side) contour filters were used. The indicated emission maxima were measured at the indicated excitation wavelengths. bRcrnn / rznz / e / γΐΛΐ Trial results Lithographic ink tests Viscosity at 20 °C [Pa-s], at 40 s-1 95 Pigment particle size, microscope [pm] 1-5 Maximum emission [nm], at λθχ = 365 nm 575-650; 675-720 Example 3 UV-curing water-based screen printing ink and safety article formed with it A printing ink has been prepared with the following composition. Composite Material Content [% by weight] Supplier First and second pigment mixture LP-H99V-04-00 20 Leuchtstoffwerk Breitungen GmbH Pearlescent pigment Colorstream T1003 8 Merck KGaA Urethane acrylate dispersion Lux 481 65.9 Alberdingk Boley GmbH Wetting additive Tego Dispers 655 0.3 Evonik Industries AG Substrate wetting additive Byk 333 1 BYK-Chemie GmbH Antifoam Agitan® 150 0.3 Münzing Chemie GmbH Photoinitiator Omnirad 500 4.5 IGM Resins BV bRcrnn / rznz / e / Ywi Manufacturing process The urethane acrylate dispersion, wetting agent, and defoamer were stirred (3000 rpm / min) with a solvent (Erichsen 492-II) for 15 minutes. The mixture of the first and second pigments and the pearlescent pigment was then added in small portions and the mixture was stirred (1000 rpm / min) until homogeneous. Finally, substrate wetting agent and photoinitiator were added, and the mixture was stirred (1000 rpm / min) for another 20 minutes. Testing methods for screen printing inks Test print The ink formulation was applied using a 12 pm K stick with an Erichsen K Control Coater on bleach-free vellum paper (Papierfabrik Louisenthal GmbH; 90 g / m² basis weight). Emission measurements These measurements are performed as described above for example 2. Goo The measurement was performed using a Haake RheoStress 6000, supplied by Thermo Scientific, with a 35 mm / 1° conical plate measurement geometry. Test results Screen printing ink tests, based on water Viscosity at 20 °C [Pa-s], at 4 s-1 4 Maximum emission [nm], at λθχ = 365 nm 575-650; 675-720 Example 4 Radiation-cured cationic screen printing ink and safety article formed with it bRcrnn / rznz / e / γΐΛΐ A printing ink has been prepared with the following composition. Material Trade Name Content [% by weight] Supplier First and second pigment mixture LP-H99V-04-00 20 Leuchtstoffwerk Breitungen GmbH Pearlescent pigment Colorstream T1003 8 Merck KGaA Cyracure UVR6110 cycloaliphatic epoxy resin 73.6 Dow Chemical Company Aerosil 200 2 Evonik Industries AG Tego Airex 900 defoamer 0.6 Evonik Industries AG SpeedCure CPTX photosensitizer 0.3 Lambson Ltd Omnicat 250 photoinitiator 3.5 IGM Resins BV Manufacturing process The cycloaliphatic epoxy resin, pyrogenic silica, antifoam, and photosensitizer were dissolved (3000 rpm / min) for 30 minutes and allowed to stand overnight. The mixture of the first and second pigments and the pearlescent pigment were then added in small portions, and the resulting mixture was dissolved (1000 rpm / min) until homogeneous. Finally, the photoinitiator was added, and the mixture was dissolved again (1000 rpm / min) for 30 minutes. Testing methods for sign printing inks Test print The ink formulation was applied using a 12 pm K stick with an Erichsen K Control Coater on bleach-free vellum paper (Papierfabrik Louisenthal GmbH; 90 g / m² basis weight). Emission measurements These measurements are performed as described above for example 2. Goo The measurement was performed using a Haake RheoStress 6000, supplied by Thermo Scientific, with a 35 mm / 1° conical plate measurement geometry. bRcrnn / rznz / e / YiAi Trial results Screen printing ink tests, Cationic curing Viscosity at 20 °C [fPa-s], at 4 s'1 3 Maximum emission [nm], at λθχ = 365 nm 575-650; 675-720 Example 5 Intaglio ink and safety article formed with it A printing ink has been prepared with the following compositions. Material Trade Name Ink Content [% by weight] Supplier First and Second Pigment Mixture LP-H99V-04-00 20% Leuchtstoffwerk Breitungen GmbH Ti-Pure Colored Pigment TS-4657 2.5% The Chemours Company TT, LLC Filler Aerosil 200, Omya EXH1 SP, Precarb 200, Claytone 40, Blanc Fixe N 36.7% Evonik Resource Efficiency GmbH, Omya AG, Bassermann minerals GmbH & Co. KG, BYKChemie GmbH, Solvay GmbH Trionol™ 9000 E Alkyd Resin 12.1% Lawter, Inc. Vegetable Oil Alberdingk Refined Linseed Oil, Alberdingk Refined Soybean Oil 10.2% Alberdingk Boley GmbH, Mercur Handel GmbH Phenol-Modified Rosin Resin Sylvaprint MP 6364 6% Arizona Chemical Ltd. Licowax® PE 190 Wax, Ceraflour 927 7.5% Clariant Plastics & Coatings Ltd., BYK-Chemie GmbH Material Trade Name Ink Content [% by weight] Supplier Dryer Borchers Dry 0246 0.7% OMG Borchers GmbH Thinner Shellsol D70, Refined Linseed Oil Alberdingk 4.3% Shell Global Solutions International BV, Alberdingk Boley GmbH bRcrnn / rznz / e / γΐΛΐ Manufacturing process First, a varnish was prepared. Phenol-modified rosin resins and vegetable oils were heated until a homogeneous mixture was formed. Afterward, the varnish was mixed with the other ingredients listed in the table, except for the oxidative drying agents. The resulting paste was ground in a three-roll laboratory mill. Finally, the oxidative drying agents were added and mixed in, and the viscosity of the ink was adjusted by adding a thinner. Test methods Test print The inks were applied using a Prüfbau MZ II printability tester. Approximately 8.0 g / m² of ink was applied to bleach-free vellum paper (Papierfabrik Louisenthal GmbH; 90 g / m² basis weight). Further test prints were produced on a Komori Corporation Currency 1-311-P intaglio proofing press and a De La Rué Giori Ormagpress master proofing press. Emission measurement These measurements are performed as described above for example 2. Goo The measurement was performed using a Haake RheoStress 6000, supplied by Thermo Scientific, with a 20 mm / 1° conical plate measurement geometry. Particle size measurement A turometer was used to determine the particle size of the pigments in the inks. The inks were poured into the deep end of the groove and scraped toward the shallow end with a flat metal scraper. At the point where the groove depth equaled the size of the largest particles in the ink formulation, irregularities (e.g., small holes in an ink sample) would become visible. The groove depth was marked on a graduated scale next to it so that the size of the largest particles in the ink formulations could be easily determined. Test results bRcrnn / rznz / e / Ywi Tests Intaglio ink Viscosity at 40 °C [Pa-s], 1000 s-1 15 Pigment particle size [pm] 6 Maximum emission [nm], at Aex = 365 nm 575-650; 675-720

Claims

1. A security ink containing at least a first fluorescent and phosphorescent pigment and a second fluorescent pigment, wherein the security ink, if excited with a first wavelength, emits radiation with a first emission spectrum, if excited with a second wavelength, emits radiation with a second emission spectrum that is different from the first emission spectrum, and after the excitation is over, emits radiation with a third emission spectrum that is different from the first emission spectrum and that is different from the second emission spectrum.

2. The security ink according to claim 1, wherein the first pigment has a first fluorescence excitation spectrum with at least one peak and a first phosphorescence excitation spectrum with at least one peak, and the second pigment has a second fluorescence excitation spectrum with at least one peak, wherein the highest peak of all the peaks of the first fluorescence excitation spectrum is at a different wavelength than the highest peak of all the peaks of the second fluorescence excitation spectrum, and wherein preferably the first phosphorescence excitation spectrum overlaps at least partially with the first fluorescence excitation spectrum and / or with the second fluorescence excitation spectrum,wherein preferably the highest peak of all the peaks of the first fluorescence excitation spectrum is shifted relative to the highest peak of all the peaks of the second fluorescence excitation spectrum from 10 to 400 nm, preferably from 20 to 300 nm, more preferably from 30 to 200 nm, and much more preferably from 40 to 140 nm.

3. The security ink according to claim 1 or 2, wherein one of the first fluorescence excitation spectrum and the second fluorescence excitation spectrum has high excitation at one or two of the wavelengths of 254 nm, 312 nm and 365 nm and low excitation at the remainder of these wavelengths, while the other of the first fluorescence excitation spectrum and the second fluorescence excitation spectrum has high excitation at at least one of the remaining wavelengths and low excitation at one or two of the wavelengths, at which the other excitation spectrum has high excitation, wherein high excitation means that the emission obtained by excitation of the respective pigment at one or two of the wavelengths of 254 nm, 312 nm and 365 nm is at least 15%, preferably at least 20%.more preferably at least 25% and most preferably more than 30% higher than the emission obtained by excitation (which is therefore called low excitation) of the same pigment at the rest of these wavelengths.

4. The security ink according to any of the preceding claims, wherein the first fluorescence emission spectrum, the second fluorescence emission spectrum, and the first phosphorescence emission spectrum each have at least one peak having a crest in the visible light range such that the security ink, if excited with a first wavelength, emits radiation with a first color, if excited with a second wavelength, emits radiation with a second color that is different from the first color, and after the excitation has ended, emits radiation with a third color that is preferably different from the first color and different from the second color.

5. The security ink according to any of the preceding claims, wherein the first pigment is selected from the group consisting of: AEAI2O4:Eu2+ (Dy3+, Ho3+, Nd3+), Zn(S,O):(Cu, Ag), AE4Ali4O25:Eu2+, Dy3+, AE2MgSi2O7:Eu2+ (Dy3+,Ho3+, Nd3+) and AE2SiO4:Eu2+ (Dy3+,Ho3+, Nd3+), wherein AE is an alkaline earth metal ion selected from the group consisting of Ca, Ba and Sr.

6. The security ink according to claim 5, wherein the first pigment is selected from the group consisting of: AEAl2 <D4:Eu2+ (Dy3+, Ho3+, Nd3+), Zn(S,O):Cu, Ag y AE4Ali4O25:Eu2+, Dy3+, en donde preferentemente el primer pigmento es SrAl2O4:Eu2+, Dy3+, en el que el contenido de Eu es del 0,1 al 10 % en bRcrnn / rznz / e / Ywi moles y en el que el contenido de Dy es del 0,1 al 1 % en moles.

7. The security ink according to any of the preceding claims, wherein the second pigment is selected from the group consisting of: Ln2Os:Do, LngCteSO₄, LnBOs:Do, LnPO₄:Do, LnVCUO₄, Ln3AlsO₂:Do, Ln3GasO₂:Do, Ln2SiO₅:Do, Ln2Si₂O₇:Do, LnVO₄:Do, in each of which Ln is selected from Se, Y, La, Gd and Lu and Do is selected from Pr, Sm, Eu, Tb, Tm and Cr, Ln2MesO₂:Do with Ln and Do as defined above and with Me selected from Mo and W, M2LnMe2Os:Do with Ln, Me and Do as defined above and with M selected from L₁, Na, K, Rb and Os, Y2O₂S:Do with Do defined as Previously, AE2S¡O4:Eu, Mg2S¡O4:Eu, ZnS:DP with DP selected from Cu, Ag and Au, LnMgAlnOig:Eu with Ln selected from La and Gd and LnMgAlnOi9:Eu, Mn with Ln selected from La and Gd.

8. The security ink according to claim 7, wherein the second pigment is selected from the group consisting of Ln2O2S:Do, ZnS:DP, LnMgAlnOi9:Eu, LnMgAlnOi9:Eu, Mn, LnVCUiDo and Y2O2S:Do, wherein preferably the second pigment is Y2O2S:Eu, wherein the Eu content is from 2 to 8 mol%.

9. The security ink according to any of the preceding claims, wherein the security ink is formulated as a printing ink selected from the group consisting of lithographic inks, intaglio inks, die-cutting inks, flexographic inks, and screen printing inks.

10. The security ink according to any of the preceding claims, wherein the security ink comprises: i) 5 to 50% by weight and preferably 10 to 30% by weight of the sum of the first pigment, the second pigment and other optional pigments, ii) 10 to 40% by weight and preferably 20 to 30% by weight of one or more binders, iii) 20 to 60% by weight and preferably 30 to 40% by weight of one or more solvents, wherein the solvent is preferably selected from the group of vegetable oils, mineral oils, wood oils and arbitrary combinations of two or more of the aforementioned solvents, and iv) optionally, 1 to 10% by weight of one or more additives selected from those belonging to the group consisting of rheological additives, adhesives, defoamers, slip additives, anti-corrosion additives, gloss additives, waxes, wetting agents, curing agents,chelating agents, photoinitiators, inhibitors, desiccants, stabilizers, emulsifiers, pH adjusting additives, abrasion resistance additives, plasticizers, antistatic additives, preservatives, light-protecting agents, mattifying agents, and arbitrary combinations of two or more of the aforementioned additives.

11. A security article, comprising: i) a substrate, ii) optionally one or more layers of printing ink and iii) a security ink according to any of the preceding claims, which is applied on at least a portion of at least one surface of the substrate or on the top layer of one or more optional layers of printing ink.

12. The security article according to claim 11, wherein the security ink is applied to a portion of a substrate surface or to the top layer of one or more optional layers of printing ink in the form of a line, a dot, a halftone, or a pattern, wherein the substrate is preferably paper, a polymer sheet, or a composite material comprising at least one paper layer and at least one polymer sheet.

13. The security article according to claim 11 or 12, wherein one or more layers of printing ink are disposed between the substrate and the security ink, wherein at least one of the one or more layers of printing ink contains at least one pigment having an emission spectrum identical or so similar to the emission spectrum of one of the first and second pigments contained in the security ink that one of the first pigment and the second pigment is obscured when excited, wherein the at least one pigment is preferably a non-fluorescent pigment and a non-phosphorescent pigment.

14. The security article according to any of claims 11 to 1, wherein one or more layers of printing ink may be disposed between the substrate and the security ink, wherein at least one of the one or more layers of printing ink may contain at least one pigment with a bifluorescent effect, wherein preferably this pigment emits in the first excitation wavelength radiation in the visible light range observable by a human being as a first color and emits in the second excitation wavelength radiation in the visible light range observable by a human being as a second color, wherein the first and second colors are different from each other.

15. A method for evaluating the authenticity of a security document comprising a security article according to any of claims 11 to 14 comprising the steps of: i) irradiating the security article with a first wavelength, wherein the first wavelength is capable of exciting the first pigment of the security ink, and determining whether fluorescence radiation is emitted from the security ink, and, if so, characterizing the fluorescence radiation, ii) terminating the irradiation with the first wavelength, iii) irradiating the security article with a second wavelength, wherein the second wavelength is capable of exciting the second pigment of the security ink, and determining whether fluorescence radiation is emitted from the security ink, and, if so, characterizing the fluorescence radiation, and iv) terminating the irradiation with the second wavelength,(yv) Determine whether phosphorescent radiation is emitted from the security ink when the security article is not irradiated with either the first or second wavelength, and, if so, characterize the phosphorescent radiation.