BR112018013997B1 - USE OF 4-BORA-3A,4A-DIAZA-S-INDACENE FOR SAFETY PURPOSES - Google Patents

Abstract

The invention relates to the use of one or more compounds of the 4-bora-3a,4a-diaza-s-indacene family for the preparation of a security element for a product, in particular a document, said security element comprising a polymer and said compounds being incorporated into said polymer, and to a method for ensuring the security of a product, in particular that of a document.

Description

[0001] This invention relates to the field of security and authentication of products, in particular documents, comprising polymers. It refers more particularly to the security and authentication of identity, fiduciary or administrative documents.

[0002] Currently, counterfeiting and fraud are increasing substantially in many high value-added sectors such as luxury products, aeronautical and automotive parts or packaging, in particular pharmaceuticals such as tablets. With the development of identity theft and the introduction in particular of dotted driver's licenses in some countries, identity and administrative documents are increasingly the target of forgery. The security and authenticity of these types of products and documents are therefore essential and involve both national and international security issues.

[0003] Thus, it is necessary to continuously provide means that make it possible to act effectively against forgery, in particular the alteration of an original document, or forgery (fraud).

[0004] In the rest of the description, the term document refers to a set formed by a support and information. The support can be of different natures, can have different shapes and can include a polymer or a mixture of polymers. This support, for example, can be wholly or partially formed from a polymer material.

[0005] As an example of mentioning a document, identity documents such as passports, identity cards, driver's licenses or health cards, but also fiduciary documents such as bank notes and checks or documents administrative costs such as, for example, registration certificates.

[0006] The documents, therefore, can be in the form of paper, booklets or in the form of a card and the information can be printed and/or engraved on the surface of the same when involving paper or a card or on the sheets when involving a booklet.

[0007] Due to the substantial value associated with the information contained, documents must be made secure.

[0008] In the field of document security, several companies provide visual authentication solutions, for example with the use of holograms or laser marking, which can make it possible to insert information into the card body made of polycarbonate, such as identity cards , health cards or driver's licenses. EP0708935 application as such describes a holographic protective layer assembly. This set is comprised of a support film having at least one layer formed by a protective varnish, a transparent or reflective layer that bears the diffraction microstructure, and finally an adhesive layer. Once the set is transferred to a document the security of the latter is achieved.

[0009] Next, this system was improved in order W02010/086522 by adding perforations in order to make it more difficult to separate the various layers. Regardless of this, it is still true that the assembly is comprised of a multiplicity of parts that must be assembled and now drilled, which represents technical restrictions in terms of time and cost.

[00010] With the development of information technology, document security has also been reinforced through the incorporation of electronic elements, such as chips, thus making counterfeiting more difficult.

[00011] Currently, documents are secured using security elements that can be classified according to three levels of security based on the medium used for detection. In this way, level 1 security elements are elements that can be detected by at least one of the five senses or through the intermediary of a contrasting background. At this level there are in particular guilloche, optically variable devices such as rainbow printing, holograms, optically variable inks, markers, changeable laser images or multiple laser images.

[00012] Level 2 security elements are elements that can be detected using simple equipment such as an ultraviolet lamp, a convex lens or a flash light from a mobile phone. This level has detectable elements such as microprints and fluorescent inks, as well as fluorescent fibers or plaques.

[00013] Finally, level 3 security elements are elements that can be detected using sophisticated equipment such as, for example, a spectrofluorometer or an electron microscope. In this category are in particular nano-engraved pigments and biometric chips as well as fluorescent markers that cannot be detected by the naked eye (taggants).

[00014] In general, a document incorporates several security elements of different levels.

[00015] Although existing security solutions are interesting, sometimes they are difficult to implement and/or control. Therefore, there is a real need for new means of security that are simple to implement, stable and that therefore allow rapid control of the authenticity of products or documents, while still providing a high level of security. These means must not be mutually exclusive.

[00016] The inventors thus succeed in developing a security means that makes it possible to control the authenticity of products comprising polymers such as documents, in particular identity, fiduciary or administrative documents, but also such as pharmaceutical packaging (in particular tablets), luxury products, cosmetic products, aeronautical and automotive parts or parts worn out in industry such as, for example, seals.

[00017] Thanks to the developed security means, the authenticity control can be carried out by three levels of security as defined here above.

[00018] In fact, thanks to the use of one or more compounds of the 4-bora-3a,4a-diaza-s-indacene family incorporated in a polymer, and particularly in the polymer matrix that constitutes the document or product in question, an element of security that can be detected at all levels is obtained.

[00019] This use is particularly advantageous as the inventors discovered that this family of fluorescent compounds can be incorporated into polymer matrices without altering the performance of the polymer, or those of the 4-bora-3a,4a-diaza-composite. s-indacene or incorporated compounds.

[00020] Thus, the purpose of the invention is the use of one or more compounds of the 4-bora-3a,4a-diaza-s-indacene family for the preparation of a security element for a product, in particular a document , said security element comprising a polymer and with the 4-bora-3a,4a-diaza-s-indacene compound(s) being incorporated into said polymer.

[00021] For the remainder of the description, use will be made of the terms "compound(s) of 4-bora-3a,4a-diaza-s-indacene" and "fluorescent dyes".

[00022] A product, in particular a document, insured in accordance with this invention will therefore include a polymer in which one or more fluorescent dyes are incorporated. These secured documents can be authenticated thanks to the properties and effects conferred by fluorescent dyes.

[00023] The polymer that incorporates one or more fluorescent dyes thus forms a security element that can also be implemented at the time the product is manufactured, in particular for the document in question, as well as can be applied or integrated later to the latter. In this way, in the security structure of a document, the security element can be present over the entire document or over a portion of the document. These points will be developed further in the description.

[00024] In any case, the products and in particular the documents obtained will be insured through the use of one or more fluorescent dyes incorporated in a polymer. Safety makes it possible to provide products with various effects and in particular the following effects: - Activation/deactivation effect (on/off): This effect corresponds to the visualization of a change in color after a stimulus of fluorescence from fluorescent dyes, in particular by an LED or UV light source. This provides level 2 security. - Waveguide effect: The presence of grooves in the layer or layer assembly generates a discontinuity in the refractive index that stimulates the fluorescence of the held layer. In this way, the color observed in the groove is different from that observed in the rest of the layer or layer set. this provides level 1 security.

[00025] 4-bora-3a,4a-diaza-s-indacene compounds are fluorescent dyes of which the first synthesis was published in 1968 (A. Treibs et al, Justus Liebigs Ann. Chem. 1968, 718, 208) . Since then, several other syntheses have been published (eg: Chem. Eur. J., 2009, 15, 5823; J. Phys. Chem. C, 2009, 113, 11844; Chem. Eur. J., 2011, 17, 3069; J. Phys. Chem. C, 20B, 117, 5373) and many 4-bora-3a,4a-diaza-s-indacene compounds are commercially available, for example, from ThermoFisher Scientific (Waltham, MA USA ).

[00026] They have considerable absorption and emission properties and have in particular fluorescent excitation and emission bands that are relatively narrow with high quantum yields Φ between 0.5 and 1, which makes them highly fluorescent. In addition, these compounds possess good photostability as well as substantial thermal stability. In fact, fluorescent dyes according to the invention are generally stable up to 300°C. thanks to this substantial thermal stability, these fluorescent dyes can be easily incorporated into polymer matrices in the molten state and, against all expectations, the performance in terms of absorption and fluorescence emission are not altered by incorporation into a polymer matrix.

[00027] The use of one or more compounds of 4-bora-3a,4a-diaza-s-indacene is also noteworthy due to the fact that products, in particular documents, insured according to the invention can be authenticated thanks to the combination unique effect of the absorbed color and the specific fluorescence that fluorescent dyes impart to the polymer. In this way, only an authentic product will have both good fluorescence absorption and emission properties.

[00028] Products, in particular documents, comprising a polymer that are secured according to the invention by incorporating one or more 4-bora-3a,4a-diaza-s-indacene compounds into the polymer can therefore be authenticated on the three levels of safety described here above thanks to the unique presence of the 4-bora-3a,4a-diaza—s—indacene compound(s). To the depositor's knowledge, this is the first time that a single security element has enabled such multi-layered security.

[00029] In fact, all 4-bora-3a,4a-diaza-s-indacene compounds have an absorption band in the visible spectrum and the color perceived by the naked eye will correspond with the complementary color of the absorbed color. For example, a compound with an absorption around 500 to 520 nm, which corresponds to a blue/green color, will appear to the naked eye as orange/red tones. This property thus makes it possible to obtain level 1 security elements.

[00030] With regard to fluorescence properties, all compounds of the 4-bora-3a,4a-diaza-s-indacene family according to the invention have excitation bands in the ultraviolet (U.V.) range and emission bands in the visible range. Therefore, they can be excited by the intermediary in particular of a U.V lamp. that emits between 100 nm and 400 nm and the fluorescence can be detected with the naked eye, which makes it possible to obtain level 2 security elements.

[00031] Finally, the emission wavelength can be determined using a single-network low-resolution spectrofluorometer or fluorometer (detection by photodiode or photomultiplier tube), which provides the security elements according to this invention with level 3 security .

[00032] In this way, the products and in particular the documents secured according to this invention will be, thanks to the association of the fluorescence and absorption properties, capable of being detected at the 3 levels.

[00033] Authentication in terms of this invention is understood as verifying the authenticity of a product, in particular a document through the detection of security elements or security means that are incorporated therein. This detection of the presence or absence of coloring or fluorescence makes it possible to authenticate or not the product, in particular a document in question.

[00034] A product, in particular a document, will therefore be authentic when it has not been reproduced and when it contains the security element or elements, as opposed to an inauthentic item which will be qualified as false, and which will not contain said elements of security thus resulting in a detection failure.

[00035] The term "incorporated" means the fact that one or more compounds of 4-bora-3a,4a-diaza-s-indacene are intimately integrated into the polymer in such a way as to form a homogeneous mixture, which does not has any dispersion. Integration of the compound or compounds into the polymer can be accomplished in a number of ways.

[00036] As an example, the integration is performed hot. In this case the polymer is heated to its melting temperature, then the 4-bora-3a,4a-diaza-s-indacene compound(s) is/are added to the melt before the whole is mixed until homogeneity is obtained.

[00037] Still as an example, the fluorescent dye is integrated in the form of a powder into the polymer. In this case, the polymer can be in the form of a light curing resin and, in order to facilitate integration, a polar solvent can be added, such as for example isopropanol. The whole is then mixed in such a way as to obtain a homogeneous mixture that does not have any dispersion, said mixture will have a particular application in certain 3D printing techniques and in particular for the manufacture of holograms.

[00038] The incorporation can be made in all types of polymer such as, for example, polycarbonate, polyester, polystyrene, polyethylene, polypropylene, polyethylene terephthalate (PET), polyacrylate, polymethacrylate, poly(vinyl chloride), polyamides, polyaramids , ethylene vinyl acetate (EVA), polyurethane, thermoplastic polyurethane (TPU), cyanoacrylate, rosin resins, pine resins, light curing resins or mixtures thereof. Preferably, the embedding can be done in a polymer chosen from polycarbonate, polyester, polypropylene, thermoplastic polyurethane and light curing resins, preferably from polycarbonate, polyester, polypropylene and mixtures thereof.

[00039] Advantageously a polymer will be used which does not contain any anti-UV additive, in order to allow an optimal maintenance of the fluorescence properties. Also advantageous is the use of a polymer which is transparent after it has been formed.

[00040] The amount of fluorescent dye to be incorporated is that required for the detection of fluorescence and absorbance properties. The fluorescent dyes according to the invention have the advantage of allowing properties to be detected even when they are incorporated into the polymer in very small amounts.

[00041] In fact, amounts of fluorescent dyes ranging from 0.01% to 5% by weight with respect to the total weight of the polymer are sufficient for detection, preferably amounts ranging from 0.01% to 2 % by weight with respect to the total weight of the polymer and even more preferably, amounts ranging from 0.01% to 0.05% by weight with respect to the total weight of the polymer.

[00042] The amounts of fluorescent dye(s) will be adapted by those skilled in the art according to the formation of the polymer and the visual effect sought. For example, the greater the visual effect of transparency sought, the smaller the amount of fluorescent dye, as well as the thickness of the shape obtained.

[00043] As mentioned here above, the polymer that incorporates one or more fluorescent compounds thus forms a security element that can be used at the time of manufacturing the product, in particular the document in question, as well as be applied or integrated a posteriori to the last. For the security of products, and in particular documents, the security element can be present over the whole document or a portion of the document on the surface as well as in the thickness of the document itself. For example, it can be present over an entire surface or only on the periphery and it can even form the document support in this way.

[00044] According to the intended use, the security element can therefore be formed by methods known to the person skilled in the art.

[00045] In fact, in one embodiment, the security element is in the form of a layer or a set of layers prepared using techniques known to those skilled in the art such as, for example, lamination, extrusion, calendering, extrusion by calendering, bulk extrusion with or without bi-extraction or varnishing and/or coating. These techniques will be chosen according to the polymer used and the final thickness of the layer or set of layers to be obtained. As an example, if the polymer is a polycarbonate or a thermoplastic polyurethane, the calendering extrusion principle will be preferred. As a further example, if the polymer is polypropylene, the bulk extrusion principle is preferred, in particular the bulk extrusion principle with bi-extraction. A set of layers in terms of this invention, for example, can be obtained by laminating two or more layers of polymer that incorporate one or more fluorescent dyes.

[00046] Such a layer or set of layers has an advantageous application in document security. Preferably, the layer or set of layers thus obtained is transparent.

[00047] The use of a transparent layer or set of layers according to this invention is particularly advantageous because, in addition to the effects described here above, the layer or set of layers has the following effects: - Color change effect: This effect corresponds to a change in color when the layer or set of layers is superimposed on a contrasting background (of the type a dark background, in particular black, or a light background, in particular white). The complementary color of the absorbed color on a light background and the fluorescence color on a dark background are thus observed. This provides level 1 security. - Side effect: This effect corresponds with the observation of a color complementary to the absorbed color that is different at the edges of the layer or set of layers, from what is observed on the surfaces. This provides level 1 security. - Tilt effect/shake effect: This effect corresponds with a change in color of a layer or the overlay of a set of layers on a reflective surface (a metallized surface, for example), said change in color that is according to the observation angle and the more or less reflective ability of the reflective background (partial reflection to total reflection). In this way, a change in pure color from the color perceived by the naked eye of the substrate to its fluorescence emission is observed. This provides level 1 security. - Shadow effect: This effect corresponds, when the fluorescence is stimulated by a lamp of the LED or UV type and as observed on a light background, in particular white, to the visualization of the fluorescence color in the layer and of the projection of the complementary color of the absorbed color on the light background. This provides level 2 security.

[00048] Advantageously, the layer in particular has a thickness ranging from 0.050 mm to 0.800 mm, preferably a thickness ranging from 0.200 mm to 0.600 mm, such as, for example, a thickness of about 0.400 mm. When the layer has a thickness of less than 0.100 mm, it is also called a film and will have a particular application in the case of flat products, in particular documents and more particularly identity, fiduciary or administrative documents and can be applied to at least a portion of one of the product surfaces.

[00049] The thickness of the layer or film is in accordance with several parameters such as the nature of the polymer used for incorporating the compound of the 4-bora-3a,4a-diaza-s-indacene family. For example, when the polymer used for incorporation is polypropylene, the layer or film obtained can advantageously have a thickness ranging from 15 µm to 100 µm. As a further example, when the polymer used for incorporation is polycarbonate, the layer or film advantageously obtained can have a thickness ranging from 100 µm to 800 µm.

[00050] According to the particular embodiment, the layer is a film and preferably has a thickness between 1 and 30 μm, such as, for example, about 10 μm. The film can be obtained according to methods known to the person skilled in the art and is preferably a bioriented film.

[00051] According to this embodiment, the bioriented films can be single-layer bioriented films or multilayer bioriented films obtained, for example, through the lamination of several layers, at least one of which contains a fluorescent compound such as as described here above. Bioriented films can be obtained by flat film extrusion, called die extrusion, or by annular extrusion (bulk extrusion). The polymer used to obtain bioriented films can be a polymer as described hereinabove, and preferably the polymer is polypropylene. Thus a film made of bioriented polypropylene is obtained.

[00052] In a particular embodiment, the layer that forms will make it possible to manufacture cards through techniques known to those skilled in the art. As an example, mention must be made of cards, professional cards, bank cards, or any other type of card that can be made from polymer. In this case, the security element forms the support of the document in this way.

[00053] Cards, for example, can be obtained by laminating several layers of polymer, at least one of which incorporates at least one fluorescent dye according to this invention.

[00054] In a particular embodiment, the security element is a film, i.e. a layer having a thickness of less than 0.100 mm, in particular ranging from 0.050 mm to 0.100 mm, which is used to laminate the two surfaces of a document, in particular an identity document. In another embodiment, such a film is applied to only one of the two surfaces of a document, in particular an identity document. In yet another embodiment, such a film is applied only to a portion of one of the two surfaces of a document, in particular an identity document. In yet another embodiment, such a film is applied only to a portion of each of the two surfaces of a document, in particular an identity document.

[00055] The 4-bora-3a,4a-diaza-s-indacene compounds implemented in this invention can be chosen from those of formula I here below: wherein, R1 is C1 to C6 alkyl, C5 to C6 cycloalkyl, C5 to C6 heteroalkyl, phenyl, said phenyl group being optionally substituted by one or more groups chosen from C1 to C2 alkyl, hydroxy, R5COO- and halogen ; R2 and R2' are independently chosen from hydrogen and C1 to C2 alkyl; R3 and R3' are independently chosen from hydrogen, aryl, heteroaryl, cycloalkyl, alkyl, alkenyl, alkynyl, said aryl, heteroaryl, cycloalkyl, alkyl, alkenyl and alkynyl which is optionally substituted by one or more groups chosen from C1 to C4 alkyl, aryl, hydroxy and ferrocene, said aryl group which is optionally substituted by one or more groups chosen from aryl, C1 to C2 alkyl, halogen, hydroxy, dimethylamino, nitro, said aryl which is optionally substituted by a C1 to C2 alkyl group; R4 and R4' are independently chosen from aryl, heteroaryl, cycloalkyl, alkyl, alkenyl, said aryl, heteroaryl, cycloalkyl, alkyl and alkenyl which is optionally substituted by one or more groups chosen from C1 to C3 alkyl, aryl , hydroxy and ferrocene, said aryl group which is optionally substituted by one or more groups chosen from aryl, C1 to C2 alkyl, halogen, hydroxy, dimethylamino, nitro, said aryl which is optionally substituted by a C1 to C2 group alkyl; R5 is C1 to C4 alkyl or C2 to C4 alkenyl. R6 and R6' are independently chosen from halogen, C1 to C4 alkyl, C2 to C4 alkenyl or aryl, said aryl being optionally substituted by one or more groups chosen from C1 to C2 alkyl, hydroxy, R5COO- and halogen.

[00056] Preferred compounds of formula I are those in which one or more of R1, R2, R2', R3, R3', R4, R4', R5, R6 and R6' are defined as follows: R1 is a substituted phenyl by one or more groups chosen from methyl, fluorine, hydroxy, acetyl and methacrylate, preferably from methyl, fluorine, hydroxy and acetyl and more preferably from methyl or fluorine; R2 and R2' are independently chosen from hydrogen and methyl; R3 and R3' are independently chosen from hydrogen, C1 to C3 alkyl, vinyl, aryl, heteroaryl, adamantane, said vinyl and aryl which is optionally substituted by one or more groups chosen from phenyl, C1 to C2 alkyl, said phenyl which is optionally substituted by one or more groups chosen from C1 to C2 alkyl, hydroxy, bromo, nitro, dimethylamine, preferably hydrogen, methyl, ethyl, n-propyl, vinyl, aryl, heteroaryl, adamantane, said vinyl and aryl which is optionally substituted by one or more groups chosen from phenyl, C1 to C2 alkyl, said phenyl which is optionally substituted by one or more groups chosen from C1 to C2 alkyl, hydroxy, bromo, nitro, dimethylamine, more preferably, R3 and R3' are independently chosen from ethyl, n-propyl, methyl, vinyl, phenyl, phenanthryl, naphthyl, pyrenyl, thiophenyl, benzofuranyl, said vinyl, aryl and naphthyl which is optionally substituted by a or various of methyl, hydroxy, bromo, nitro and dimethylamino; R4 and R4' are independently chosen from methyl, vinyl, aryl, heteroaryl, adamantane, said vinyl and aryl which is optionally substituted by one or more groups chosen from phenyl, C1 to C2 alkyl, said phenyl which is optionally substituted by one or more groups chosen from C1 to C2 alkyl, hydroxy, bromo, nitro, dimethylamine, preferably R4 and R4' are independently chosen from methyl, vinyl, phenyl, phenanthryl, naphthyl, pyrenyl, thiophenyl, benzofuranyl said vinyl, aryl and naphthyl which is optionally substituted by one or more of methyl, hydroxy, bromo, nitro and dimethylamino; R5 is methyl or ethenyl. R6 and R6' are independently chosen from fluorine, C1 to C4 alkyl, C2 to C4 alkenyl or aryl, said aryl being optionally substituted by one or more groups chosen from C1 to C2 alkyl, hydroxy, R5COO- and halogen, preferably R6 and R6' are fluorine.

[00057] According to one embodiment, the 4-bora-3a,4a-diaza-s-indacene compounds implemented in this invention can be chosen from those of formula II here below: R1 is C1 to C6 alkyl, C5 to C6 cycloalkyl, C5 to C6 heteroalkyl, phenyl, said phenyl group being optionally substituted by one or more groups chosen from C1 to C2 alkyl, hydroxy, R5COO- and halogen; R2 and R2' are independently chosen from hydrogen and C1 to C2 alkyl; R3 and R3' are independently chosen from hydrogen and C1 to C3 alkyl; R4 and R4' are independently chosen from aryl, heteroaryl, cycloalkyl, alkyl, alkenyl, said aryl, heteroaryl, cycloalkyl, alkyl and alkenyl which is optionally substituted by one or more groups chosen from C1 to C3 alkyl, aryl , hydroxy and ferrocene, said aryl group which is optionally substituted by one or more groups chosen from aryl, C1 to C2 alkyl, halogen, hydroxy, dimethylamino, nitro, said aryl which is optionally substituted by a C1 to C2 group alkyl; R5 is C1 to C4 alkyl or C2 to C4 alkenyl.

[00058] Preferred compounds of formula I of this embodiment are those in which one or more of R1, R2, R2', R3, R3', R4, R4' and R5 are defined as follows: R1 is a phenyl substituted by one or more groups chosen from methyl, fluorine, hydroxy, acetyl and methacrylate, preferably from methyl, fluorine, hydroxy and acetyl and more preferably from methyl or fluorine; R2 and R2' are independently chosen from hydrogen and a methyl; R3 and R3' are independently chosen from hydrogen, methyl, ethyl, n-propyl and preferably ethyl; R4 and R4' are independently chosen from methyl, vinyl, aryl, heteroaryl, adamantane, said vinyl and aryl which is optionally substituted by one or more groups chosen from phenyl, C1 to C2 alkyl, said phenyl which is optionally substituted by one or more groups chosen from C1 to C2 alkyl, hydroxy, bromo, nitro, dimethylamine, preferably R4 and R4' are independently chosen from methyl, vinyl, phenyl, phenanthracenyl, naphthalenyl, pyrenyl, thiphenyl, benzofuranyl said vinyl, aryl and naphthalenyl which is optionally substituted by one or more of methyl, hydroxy, bromo, nitro and dimethylamino; R5 is methyl or ethenyl.

[00059] Particular preferred compounds of formula I are those in table 1 hereafter: Table 1:

[00060] For the description of the compounds implemented in this invention, the terms and expressions used shall, unless otherwise mentioned, be interpreted in accordance with the definitions hereafter.

[00061] The term "halogen" means fluorine, chlorine, bromine or iodine. Preferred halogen groups are fluorine and bromine, fluorine being particularly preferred.

[00062] The term "alkyl" designates a hydrocarbon radical of the formula CnH2n+1, linear or branched, in which n is an integer greater than or equal to 1. Preferred alkyl groups are linear C1 to C6 alkyl groups or branched.

[00063] The term "alkenyl" designates an unsaturated alkyl group, linear or branched, comprising one or more carbon-carbon double bonds. Suitable alkenyl groups include from 2 to 6 carbon atoms, preferably from 2 to 4 carbon atoms and even more preferably 2 or 3 carbon atoms. Non-limiting examples of alkenyl groups are ethenyl (vinyl), 2-propenyl (allyl), 2-butenyl and 3-butenyl, ethenyl and 2-propenyl being preferred.

[00064] The term "cycloalkyl", alone or as part of another group, designates a mono-, di- or tri-cyclic saturated hydrocarbon radical having 3 to 12 carbon atoms, in particular 5 to 10 carbon atoms, more particularly 6 to 10 carbon atoms. Suitable cycloalkyl radicals include, but are not limited to, cyclopentyl, cyclohexyl, norbornyl, adamantane, in particular cyclohexyl and adamantane. Preferred cycloalkyl groups include cyclohexyl, 1-adamantane and 2-adamantane.

[00065] The term "aryl" denotes a polyunsaturated, aromatic, monocyclic (for example, phenyl) or polycyclic (for example, naphthyl, anthracene, phenanthryl, pyrenyl) hydrocarbon radical. Preferred aryl groups include phenyl, naphthyl, phenanthryl, pyrenyl anthracene.

[00066] The term "heteroaryl" designates an aromatic ring having from 5 to 12 carbon atoms in which at least one carbon atom is replaced with an oxygen, nitrogen or sulfur atom or with -NH, said nitrogen atoms and sulfur can optionally be oxidized and said nitrogen atom optionally can be quaternized, or a cyclic system containing 2 to 3 fused rings each typically containing 5 or 6 atoms and of which at least one ring is aromatic, at least one carbon atom of at least one aromatic ring being replaced with an oxygen, nitrogen or sulfur atom or with -NH, said nitrogen and sulfur atoms may optionally be oxidized and said nitrogen atom may optionally be quaternized. Examples of heteroaryl groups include furanyl, thiophenyl, pyrrolyl, pyridinyl and benzofuranyl.

[00067] The compounds implemented in this invention can be synthesized according to methods known to the person skilled in the art. Reference may be made in particular to the publication by A. Loudet et al. (Chem. Rev. 2007, 107, 48914932).

[00068] Another object of this invention is thus a security element as described here above.

[00069] This invention also aims at a method for securing a product, in particular a document, which implements a security element as defined hereinabove.

[00070] The security method comprises: - preparing a security element as defined here above, said security element capable of forming the product and in particular the document in this way, or - being applied to said product and in particular to the said document to be insured.

[00071] In the case where the security element does not form the product as such, the application on the product to be secured is implemented by techniques known to the person skilled in the art in accordance with said product and in particular said document to be secured.

[00072] For example, if the product to be insured is a document and in particular an identity document, the application of the security element can be carried out by laminating it on at least a portion of one of the surfaces of the document.

[00073] In a particular embodiment, the product to be secured is a document such as, for example, an identity, fiduciary or administrative document and the security element thus can be applied to at least a portion of a surface of the product.

[00074] In an alternative form of this embodiment, the security element is a film that is laminated on the two surfaces of a document. Lamination can be performed cold or hot. In another alternative form, the film is applied to only one of two surfaces of a document. In yet another alternative form, the film is applied to only a portion of one of the two surfaces of a document. In yet another alternative form, the film is applied only to a portion of each of the two surfaces of a document.

[00075] According to another embodiment, the security element is a film that is laminated on at least one face comprising a reflective surface. A reflective surface is a surface whose capabilities for reflection are controlled. For example, the reflective surface can be a metallised surface. In this way, the security element can be a set of several layers of which at least one of them comprises a metallized surface on which a polymer film is laminated which incorporates the compounds of the 4-bora-3a,4a-diaza-s family - indacene such as here above.

[00076] In a particular embodiment, the security element is a layer laminated on either side by at least one polymer layer that does not contain any fluorescent dye, in this way the security element forms the card core.

[00077] According to the particular embodiment, the security element is a varnish and thus can be applied to the surface of a product to be secured. The surface on which the varnish is applied in particular can be a reflective surface. According to this embodiment, said application can be carried out by varnishing and/or coating and makes it possible in particular to obtain a layer or a film that advantageously has a thickness ranging from 1 μm to 40 μm. In terms of this invention, a varnish is an unpigmented composition, which may be comprised of binders, solvents and optionally diluent and/or additives.

[00078] In a particular embodiment, the security element is an ink, in particular an ink for offset printing, comprising in its formulation a polymer in which a fluorescent compound is integrated, said polymer being in particular a resin and particularly a rosin resin or a pine resin. In terms of this invention, an ink is a pigmented composition that can be used for writing, drawing or printing.

[00079] This ink can be used for the security of the product and in particular a document, by application on said product or said document. Advantageously, the use of a hold paint according to this invention makes it possible to obtain layers with a thickness ranging from 1 µm to 40 µm. The application can be carried out on the surface of said product or said document to be held or on an element forming the latter. The constituting element, for example, can be a reflective surface, said surface capable of being metallised or not, a polyester or polypropylene film, said film being partially or entirely comprised of a transparent and/or reflective region. The application can be carried out according to techniques known to the person skilled in the art such as, in particular, offset printing or screen printing, techniques which will be chosen according to the product or document support to be secured.

[00080] When they are used in offset printing, the inks handled according to this embodiment have the advantage of limiting clogging of the print heads since the fluorescent components are less occlusive than pigments or dyes that are conventionally used .

[00081] In another particular embodiment, the security element is an adhesive comprising a polymer in which a fluorescent compound is integrated. This adhesive can be used for securing the product and in particular a document by affixing it to said product or document to be secured. By way of example, adhesives secured in this way can be used to manufacture packaging.

[00082] The products to be insured can be of any nature. This could be, for example, packaging such as tablets or plastic, documents such as identity, fiduciary or administrative documents such as registration certificates.

[00083] The invention should be better understood using figures and examples that follow, which are intended for the purposes of illustration and are in no way limiting.

Figures

[00084] Figure 1 shows the absorption spectrum of polycarbonate layers with a thickness of about 0.400 mm which respectively incorporate 0.05% and 0.005% by weight of fluorescent dye.

[00085] Figure 2 shows the fluorescence spectrum of a polycarbonate layer with a thickness of about 0.400 mm that incorporates 0.005% by weight of fluorescent dye.

[00086] Figure 3 shows the transmission spectrum of a polycarbonate layer with a thickness of about 0.400 mm that incorporates 0.1% by weight of fluorescent dye.

Examples

[00087] Example 1: Preparation of a transparent layer of a security element with a polycarbonate polymer base incorporating a fluorescent dye.

[00088] For this example of a security element, the chosen polymer is polycarbonate sold under the reference Makrolon® 2658 by Bayer.

[00089] The fluorescent dye chosen is 2,8-diethyl-5, 5-difluoro-10-mesityl-3, 7-di(thiophen-2-yl)-5H-dipyrrolo[1,2-c:2', 1'-f][1,3,2]diazaborinin-4-io-5-uide of formula:

[00090] This fluorescent dye absorbs at 590 nm and has a fluorescence emission at 641 nm.

[00091] In order to determine the amounts of fluorescent dyes to be incorporated in order to obtain a transparent layer, the following four test compositions were prepared: Composition 1: Makrolon® 2658 polycarbonate mixed with 1% fluorescent dye. Composition 2: Makrolon® 2658 polycarbonate mixed with 0.05% fluorescent dye. Composition 3: Makrolon® 2658 polycarbonate mixed with 0.0167% fluorescent dye. Composition 4: Makrolon® 2658 polycarbonate mixed with 0.005% fluorescent dye.

[00092] The percentages are expressed in weight with respect to the total weight of the fluorescent dye.

[00093] The four compositions were then extruded using a PLASTI-CORDER® extruder sold by BRADENDER and which has the following characteristics - Screw diameter: 25 mm - Screw length: 40 D - Speed range: 0 to 150 rpm - Maximum torque: 2x90 Nm - Two filling sections - One degassing section - Temperature range for extrusion: 260°C to 290°C - Extrusion pressure: ambient pressure

[00094] The extruder makes it possible to obtain granules or beads that will undergo a thermocompression step in order to obtain layers of security element. The granules or beads were therefore thermo-compressed in moulds.

[00095] The equipment used for this step is a LESCUYER press in which the press plates were heated to 290 °C and compression was performed at 5 MPa (50 bar) for 2 to 3 min.

[00096] After cooling, layers of security element of 10 cm x 10 cm are obtained and have a thickness of about 0.400 mm.

[00097] For each composition, a layer was prepared according to the description here above.

[00098] For each layer, the absorption and fluorescence spectra were recorded.

[00099] Figure 1 shows the absorption spectra of polycarbonate layers that incorporate 0.05% and 0.005% by weight of fluorescent dye, respectively. A bathochromic shift (shift) is observed from Àmax with respect to the absorption spectrum of the fluorescent dye in the solution which has an Àmax of 588 nm. For this layer made of polycarbonate, the actually measured absorption λmax is 600 nm (0.05% fluorescent dye) and 599 nm (0.005% fluorescent dye). The maximum absorbances (absmax) and the concentration in the fluorescent dye were also determined. The latter was determined using the e value in solution (45000 mol.L-1.cm-1). The results are summarized in Table 2 here below. Table 2:

[000100] Figure 2 shows the fluorescence spectra of the polycarbonate layer containing 0.005% fluorescent dye with an excitation wavelength of 580 nm and 600 nm respectively. A slight hypsochromic shift (shift) of Àmax is observed relative to the fluorescence spectrum of the fluorescent dye in the solution which has an Àmax of 644 nm. For this layer made of polycarbonate, the measured Àmax is actually 641 nm for an excitation wavelength of 600 nm and 640 nm for an excitation wavelength of 580 nm.

[000101] With regard to light transmission, the layer obtained using composition 1, with a concentration in the fluorescent dye of 0.1% by weight with respect to the total weight of the polymer, does not transmit below 650 nm (cf. figure 3) .

[000102] Composition 3 makes it possible to obtain a layer of transparent fluorescent security element that allows the light to pass through which makes it possible to change the color according to the incident light beams.

[000103] Other tests were conducted by varying the fluorescent dyes used, but while retaining the same concentrations. Films having absorbance wavelengths ranging from 516 nm to 727 nm and fluorescence wavelengths ranging from 527 nm to 742 nm were thus obtained.

[000104] Example 2: Preparation of a transparent layer of a security element based on thermoplastic polyurethane polymer that incorporates a fluorescent dye.

[000105] For this example, the chosen polymer is the thermoplastic polyurethane sold under the reference Desmopan® DP 9386A from Bayer.

[000106] The fluorescent dye chosen is 2,8-diethyl-5,5-difluoro-1,3,7,9-tetramethyl-10-(perfluorophenyl)-5H-dipyrrolo[1,2-c:2',1 '-f][1,3,2]diazaborinin-4-io-5-uida from the formula here below (OVM 6):

[000107] The chosen dye absorbs at 544 nm and has a fluorescence emission at 558 nm.

[000108] In order to obtain a transparent fluorescent layer, three test compositions were prepared as follows: Composition 1: thermoplastic polyurethane Desmopan® DP 9386A mixed with 0.05% fluorescent dye. Composition 2: Desmopan® DP 9386A thermoplastic polyurethane mixed with 0.0167% fluorescent dye. Composition 3: Desmopan® DP 9386A thermoplastic polyurethane mixed with 0.005% fluorescent dye.

[000109] The percentages are expressed in weight with respect to the total weight of the fluorescent dye.

[000110] For each composition, a layer was prepared according to an operating procedure identical to that of example 1.

[000111] The three compositions prepared with the base of thermoplastic polyurethane polymer make it possible to obtain layers of security element that have the same appearance and the same transparency as those obtained with the compositions prepared with the base of polycarbonate polymer.

[000112] Spectrophotometric analyzes of the various layers of security element obtained show that the incorporation of fluorescent dye to thermoplastic polyurethane does not alter its performance in terms of absorption and fluorescence emission.

[000113] The possibilities of incorporating fluorescent dyes of this invention are thus demonstrated.

Claims (24)

1. Use of one or more compounds of the 4-bora-3a,4a-diaza-s-indacene family characterized in that it is for the preparation of a security element of a product, in particular a document, said element security comprising a polymer and said compound or compounds being incorporated into said polymer and are chosen from those of formula I: wherein, R1 is a phenyl substituted by one or more groups chosen from methyl, fluorine, hydroxy, acetyl and methacrylate, preferably from methyl, fluorine, hydroxy and acetyl and more preferably from methyl or fluorine; R2 and R2' are independently chosen from hydrogen and C1 to C2 alkyl; R3 and R3' are independently chosen from hydrogen, aryl, heteroaryl, cycloalkyl, alkyl, alkenyl, alkynyl, said aryl, heteroaryl, cycloalkyl, alkyl, alkenyl and alkynyl being optionally substituted by one or more groups chosen from C1 to C4 alkyl, aryl, hydroxy and ferrocene, said aryl group being optionally substituted by one or more groups chosen from aryl, C1 to C2 alkyl, halogen, hydroxy, dimethylamino, nitro, said aryl being optionally substituted by a group C1 to C2 alkyl; R4 and R4' are independently chosen from aryl, heteroaryl, cycloalkyl, alkyl, alkenyl, said aryl, heteroaryl, cycloalkyl, alkyl and alkenyl being optionally substituted by one or more groups chosen from C1 to C3 alkyl, aryl, hydroxy and ferrocene, said aryl group being optionally substituted by one or more groups chosen from aryl, C1 to C2 alkyl, halogen, hydroxy, dimethylamino, nitro, said aryl being optionally substituted by a C1 to C2 alkyl group; R5 is C1 to C4 alkyl or C2 to C4 alkenyl. R6 and R6' are independently chosen from halogen, C1 to C4 alkyl, C2 to C4 alkenyl or aryl, said aryl being optionally substituted by one or more groups chosen from C1 to C2 alkyl, hydroxy, R5COO- and halogen . 2. Use according to claim 1, characterized in that the compound or compounds from the 4-bora-3a,4a-diaza-s-indacene family are chosen from: 3. Use, according to any of the preceding claims, characterized in that the polymer is chosen from polycarbonate, polyester, polystyrene, polyethylene, polypropylene, polyethylene terephthalate, polyacrylate, polymethacrylate, poly(vinyl chloride), polyamides , polyaramids, ethylene vinyl acetate (EVA), polyurethane, thermoplastic polyurethane (TPU), cyanoacrylate, rosin resins, pine resins, light curing resins or mixtures thereof. 4. Use according to claim 3, characterized in that the polymer is chosen from polycarbonate, polyester, polypropylene, thermoplastic polyurethane or light-curing resins, preferably polycarbonate and thermoplastic polyurethane or mixtures thereof. 5. Use, according to claim 4, characterized by the fact that the polymer is polycarbonate, polyester, polypropylene or mixtures thereof. 6. Use, according to any of the preceding claims, characterized by the fact that the product is an identity, fiduciary or administrative document. 7. Use according to any one of claims 1 to 6, characterized in that the security element is in the form of a layer. 8. Use according to any one of claims 1 to 6, characterized in that the security element is an ink or varnish. 9. Use according to any one of claims 1 to 6, characterized in that the security element is an adhesive. 10. Security element of a product, in particular a document, said security element characterized in that it comprises a polymer and one or more compounds from the 4-bora-3a,4a-diaza-s-indacene family, the said compound or compounds being incorporated into said polymer and are chosen from those of formula I: wherein, R1 is a phenyl substituted by one or more groups chosen from methyl, fluorine, hydroxy, acetyl and methacrylate, preferably from methyl, fluorine, hydroxy and acetyl and more preferably from methyl or fluorine; R2 and R2' are independently chosen from hydrogen and C1 to C2 alkyl; R3 and R3' are independently chosen from hydrogen, aryl, heteroaryl, cycloalkyl, alkyl, alkenyl, alkynyl, said aryl, heteroaryl, cycloalkyl, alkyl, alkenyl and alkynyl being optionally substituted by one or more groups chosen from C1 to C4 alkyl, aryl, hydroxy and ferrocene, said aryl group being optionally substituted by one or more groups chosen from aryl, C1 to C2 alkyl, halogen, hydroxy, dimethylamino, nitro, said aryl being optionally substituted by a group C1 to C2 alkyl; R4 and R4' are independently chosen from aryl, heteroaryl, cycloalkyl, alkyl, alkenyl, said aryl, heteroaryl, cycloalkyl, alkyl and alkenyl being optionally substituted by one or more groups chosen from C1 to C3 alkyl, aryl, hydroxy and ferrocene, said aryl group being optionally substituted by one or more groups chosen from aryl, C1 to C2 alkyl, halogen, hydroxy, dimethylamino, nitro, said aryl being optionally substituted by a C1 to C2 alkyl group; R5 is C1 to C4 alkyl or C1 to C4 alkenyl. R6 and R6' are independently chosen from halogen, C1 to C4 alkyl, C2 to C4 alkenyl or aryl, said aryl being optionally substituted by one or more groups chosen from C1 to C2 alkyl, hydroxy, R5COO- and halogen . 11. Security element, according to claim 10, characterized in that the compound or compounds of the 4-bora-3a,4a-diaza-s-indacene family are chosen from: 12. Security element according to any one of claims 10 and 11, characterized in that the polymer is chosen from polycarbonate, polyester, polystyrene, polyethylene, polypropylene, polyethylene terephthalate, polyacrylate, polymethacrylate, poly(chlorine chloride) vinyl), polyamides, polyaramids, ethylene vinyl acetate (EVA), polyurethane, thermoplastic polyurethane (TPU), or cyanoacrylate, rosin resins, pine resins, light curing resins or mixtures thereof. 13. Security element according to claim 12, characterized in that the polymer is chosen from polycarbonate, polyester, polypropylene, thermoplastic polyurethane and light-curing resins, preferably from polycarbonate and thermoplastic polyurethane. 14. Security element, according to claim 13, characterized in that the polymer is polycarbonate, polyester, polypropylene or mixtures thereof. 15. Security element according to any one of claims 10 to 14, characterized in that it has the form of a layer. 16. Security element, according to claim 15, characterized in that the layer has a thickness ranging from 0.050 mm to 0.800 mm, preferably from 0.200 mm to 0.600 mm and more preferably a thickness of about 0.400 mm. 17. Security element, according to claim 15, characterized in that the layer is a film. 18. Security element, according to claims 12 and 15, characterized by the fact that the polymer is polycarbonate and by the fact that it has the form of a layer with a thickness ranging from 100 μm to 800 μm. 19. Security element, according to claims 12 and 15, characterized by the fact that the polymer is polypropylene and by the fact that it has the form of a layer with a thickness ranging from 15 μm to 100 μm. 20. Security element according to any one of claims 10 to 14, characterized in that the security element is a paint or varnish. 21. Security element according to any one of claims 10 to 14, characterized in that the security element is an adhesive. 22. Method for securing a product, in particular a document, the method being characterized in that it comprises a step of preparing a security element as defined in any one of claims 10 to 21, said security element capable of form the product and in particular the document in this way, or be applied to said product and in particular to said document to be held. 23. Method, according to claim 22, characterized in that the application of said security element is carried out on at least a portion of said product, in particular of said document, to be secured. 24. Method, according to claims 22 or 23, characterized by the fact that the product to be insured is an identity, fiduciary or administrative document.