Security document comprising a polymer substrate

Abstract

The invention relates to a security document (10) comprising: - a non-opaque polymeric substrate (11) comprising a polymer produced at least partially with at least one bio-based material; and - one or more opacifying covering layers (12, 13, 14) partially covering the substrate (11) and providing at least one window (20) in which the substrate (11) is free of covering layer.

Description

[0001] Description

[0002] Title: Safety document containing a polymer substrate

[0003] The present invention relates to security documents comprising a polymer substrate and a method for authenticating or identifying security documents, in particular security documents of the invention.

[0004] technical field

[0005] The term “security document” refers to a security or valuable document, such as a means of payment, for example a banknote, a check, a bank card or a restaurant voucher, an identity document, such as an identity card, a visa, a passport or a driver's license, a lottery ticket, a transport ticket or even an entry ticket to cultural or sporting events.

[0006] The present invention relates to polymer substrates. By "polymer substrate" or "polymeric substrate" is meant a substrate composed of a synthetic hydrocarbon polymer.

[0007] Security features are enhanced by the addition of security elements. These elements can be introduced either during paper production, particularly in the form of fibers, particles or particle agglomerates, films, yarns, or knitted structures, or after manufacturing, particularly in the form of films or patches. They can offer one or more levels of security, enabling the identification and / or authentication of the security feature. The majority of security and reinforcement elements that can be applied to or embedded in the substrate are made from polymers.

[0008] The use of polymers for the substrate or safety elements makes it possible in particular to improve the mechanical properties of the final material, mainly tear resistance (according to ISO 1974) and / or double-fold resistance (according to ISO 5626), as well as resistance to soiling, in particular to wet soiling.

[0009] The majority of polymers used in safety documents and their associated components are synthetic and derived from petroleum-based fossil resources (polyamide, polyethylene terephthalate, polypropylene, etc.). Such polymers have a significant environmental impact. Alternatives to these polymers have already been proposed in some cases.

[0010] Prior art: International application WO202328627 is known to describe a safety document, safety feature, or substrate comprising a recycled material, and / or manufactured from renewable raw materials, and / or biodegradable materials, and / or marine materials. The material may be translucent.

[0011] International application WO2014033658 also refers to a safety document having a fibrous substrate with an attached safety element or reinforcement comprising at least one hydrocarbon-based synthetic polymer derived at least partially from plant resources. The safety element may be a safety thread or a patch and is attached to or within the safety document. The reinforcement element may be a fiber attached to or embedded in the substrate or a film attached to the substrate. The substrate for the safety element or the safety film may be made at least partially from a hydrocarbon-based synthetic polymer derived at least partially from plant resources, preferably selected from polyethylene terephthalate-based polymers, and may be transparent.This document mentions that the use of one or more synthetic hydrocarbon polymers instead of conventional synthetic or artificial polymers makes it possible to secure the substrate, in particular through isotope-loaded reinforcing elements. 14 C, and the isotope-loaded safety elements 14 C added to the substrate, notably by determining the bio-based material content according to the American standard ASTM D6866.

[0012] There is a need to further increase the security of documents, while addressing current environmental issues, particularly in terms of biodegradability, recycling and / or waste recovery.

[0013] Description of the invention

[0014] The invention addresses this need through a safety document comprising:

[0015] - a non-opaque polymeric substrate comprising a polymer produced at least partially with at least one bio-based material, and

[0016] - one or more opacifying coating layers partially covering the substrate and leaving at least one window in which the substrate is free of coating layer.

[0017] The eco-friendly nature of the substrate is a fundamental aspect of the invention. By using at least some renewable and bio-based raw materials, such as plant waste or used industrial cooking oils, the substrate contributes to reducing the carbon footprint and promoting waste recovery. This approach aligns with sustainable development principles and meets the growing demands for eco-design in products. Furthermore, the possibility of using biodegradable polymers offers an alternative to traditional petrochemical-based polymers, thus facilitating the integration of more environmentally friendly solutions into the lifecycle of security documents.

[0018] Furthermore, given their carbon-14 content, bio-based materials can provide intrinsic security to the safety document, independent of additional elements. Indeed, they offer the possibility of authentication and / or identification through the detection of carbon-14 content and / or by determining the percentage of bio-based material according to ASTM D6866.

[0019] ASTM D6866 is equivalent to the international standard ISO 16620 and the French standard NF 16640, both of which are derived from the American standard ASTM D6866. In the following sections, any identification of the presence of carbon-14 isotope content or determination of bio-based material content will be carried out according to one of these standards. This will not be specified further.

[0020] The presence of a window in the document, free from varnish or other overlay elements, allows, by taking a sample from the easily identifiable window, a direct and precise measurement of the composition in terms of bio-based material of the polymer substrate only, without disturbance of other layers or additional elements, thus guaranteeing a reliable assessment of the rate of bio-based material in the substrate.

[0021] Substrate

[0022] Preferably, the substrate is a polymer or a mixture of polymers. In the case where it is a mixture of polymers, each polymer can be at least partially derived from bio-based material.

[0023] Preferably, bio-based material is a renewable and biodegradable plant material or a mixture of renewable and / or biodegradable plant materials.

[0024] The polymer(s) derived at least partially from bio-based material may be chosen from among synthetic hydrocarbon polymers derived at least partially from plant resources. "Synthetic hydrocarbon polymer derived at least partially from plant resources" means a polymer obtained by chemical synthesis from at least one monomer of plant origin, this monomer being able to be obtained from certain parts of plants, for example by fermentation, mechanical extraction, chemical extraction, enzymatic treatment and / or catalyzed chemical reaction.

[0025] The polymer(s) derived at least partially from bio-based material can be produced from plant waste, for example used industrial cooking vegetable oils.

[0026] The polymer(s) produced at least partially with at least one bio-based material may be chosen from polyamide (PA), polyundecanamide (PAU), polyethylene terephthalate (PET), polyethylene furanoate (PEF), polybutylene succinate, polyhydroxy alkanoate, polypropylene (PP), in particular biaxially oriented (BoPP), polylactic acid (PLA), cellulose diacetate (CDA), cellophane films and mixtures thereof.

[0027] Preferably, the polymer(s) may be derived, in a proportion greater than or equal to 20% by mass, better greater than or equal to 50% by mass, even better greater than or equal to 70% by mass, even better greater than or equal to 80% by mass, from bio-based material.

[0028] The substrate can be multilayered, in particular in a plurality of layers each in a polymer produced at least partially with at least one bio-based material, in particular in the same polymer.

[0029] The substrate may consist of a core and one or two treated outer layers. The outer layer(s) may be one or more layers of the same polymer as the core, subjected to a treatment, such as a treatment that facilitates adhesion of the outer layer(s) and / or printing, for example, a corona treatment. This allows for a substrate with predetermined surface properties depending on the intended use and the outer layer(s).

[0030] Alternatively, the substrate is single-layered.

[0031] The substrate may be pigment-free and / or filler-free. This allows for a substrate containing bio-based materials solely within the polymer, exhibiting desirable optical properties, particularly transparency. Alternatively, the substrate may be opaque and contain pigments or fillers in bulk. Preferably, the substrate is transparent. "Transparent" is defined as a visible light transmission greater than typically 80%, ideally greater than or equal to 90%. Such transparency facilitates the visibility of the window when observing the security document in transmission. Indeed, the absence of any overlying elements in the window ensures the transparency of this area and allows for easy identification of the area to be sampled for authentication or identification of the security document by detecting the carbon-14 isotope content.Authentication and / or identification is therefore not contaminated by printing and varnish or any other element that could disrupt the assessment of the rate of bio-based materials.

[0032] Preferably, the substrate is free of pigment absorbing in the infrared, UV and / or visible range.

[0033] Preferably, the substrate is transparent to UV, visible and / or IR light.

[0034] The substrate can be free of paper fiber, better yet, free of all fiber.

[0035] Cover layers

[0036] One or more of the overlay layers is an opacifying layer, specifically a pigment layer.

[0037] One or at least one of the overlay layers may be a print.

[0038] The opacifying layer and / or the printing process may contain bio-based pigments. This contributes to the eco-responsibility of the security document by using renewable resources and reducing dependence on petrochemical-derived materials. Furthermore, like the substrate, it can also provide additional security and offer the possibility of further authentication or identification through the detection of the bio-based material.

[0039] The opacifying layer may also contain a binder.

[0040] The opacifying layer can cover the substrate surface completely outside the window(s). Alternatively, the pigmented opacifying layer partially covers the substrate. It can form a specific pattern on the substrate.

[0041] Bio-based pigments may contain bio-based calcium carbonate, notably selected from eggshell powders of various birds, including chickens, quail, pheasants, turkeys, ostriches, geese, pigeons, or guinea fowl, or from shellfish, including oyster, mussel, scallop, clam, periwinkle, cockle, whelk, clam, cockle, razor clam, abalone, clam, limpet, queen scallop, or tellin shells, particularly scallop, oyster, mussel, or mixtures thereof. The presence of a bio-based calcium carbonate filler in the form of eggshell powder within a pigment opacifying layer facilitates drying due to the porous properties of eggshells.

[0042] All the pigments in the opacifying layer and / or the printing can be of bio-based origin.

[0043] The binder can be a UV curing resin, a solvent-based or aqueous resin, latex, or a dispersion resin.

[0044] The binder can be at least partially of bio-based origin, in particular more than 30% by mass, better more than 50% by mass of bio-based origin.

[0045] The bio-based material content of the opacifying layer, determined according to the aforementioned standards, may be greater than 1%, better greater than or equal to 2%, even better greater than or equal to 10%, even better greater than or equal to 50% or greater than or equal to 90%.

[0046] One or more of the cover layers may exhibit biocidal properties, including antibacterial, antifungal and / or antiviral properties.

[0047] One or more of the topcoat layers may be a varnish.

[0048] The layer(s) may form a multilayer surface structure extending to one side or both sides of the substrate, outside of at least one window. The multilayer surface structure may include a pigment opacifying layer extending over part of the substrate, an imprint on the pigment opacifying layer, and a surface varnish.

[0049] Window

[0050] Preferably, in the window, the substrate is present at more than 90% by mass, better at more than 95% by mass, even better at more than 98% by mass.

[0051] Preferably, the substrate within the window is free of surface printing. Alternatively, the security document includes printing that partially covers the substrate within the window.

[0052] Preferably, the substrate in the window is devoid of any optical structure, including micromirrors, microlenses, or holographic features. Alternatively, the security document includes an optical structure, including micromirrors, microlenses, or holographic features, in the window.

[0053] Preferably, the security document presents an area in the transparent window exposed to visible, UV and / or infrared light.

[0054] Preferably, the security document is transparent in the window. By "transparent," we mean that more than 90%, or better yet more than 95%, of the incident visible light is transmitted through the security document into the window.

[0055] Preferably, the safety document includes at least one area of ​​the window without any visible safety element in which only the substrate is present.

[0056] Preferably, the safety document should include at least one area within the window where only the substrate is present. Preferably, only the substrate should be present throughout the entire window.

[0057] Preferably, the security document is free of a layer covering the substrate in at least one area of ​​the window.

[0058] Security document

[0059] The security document may include one or more additional security features, such as fibers, particles or particle agglomerates, patches, boards, films, woven or knitted structures, or security threads outside at least one window. These features may be introduced into the substrate, such as fibers, particles or particle agglomerates, films, security threads, or woven or knitted structures, or applied to the substrate or one of the overlay layers, such as films, security threads, woven or knitted structures, or patches, and may include one or more security levels enabling the identification and / or authentication of the security document.

[0060] Among these additional security features, some are detectable to the naked eye, in daylight or artificial light, without the use of any special equipment. These security features include, for example, colored fibers or strips, printed or metallized security threads (fully or partially), a secure knitted structure, a security film, a watermark, and optically variable elements (OVDs), including holograms. These are considered first-level security features.

[0061] Other types of additional security features are detectable only with a relatively simple device, such as a lamp emitting ultraviolet (UV) or infrared (IR) light. These security features include, for example, fibers, strips, tapes, threads, or particles or particle aggregates. These security features may or may not be visible to the naked eye; for example, they may be luminescent under the illumination of a Wood's lamp emitting at a wavelength of 365 nm. These are referred to as second-level security features.

[0062] Other types of additional security features require more sophisticated detection devices. These features, for example, are capable of generating a specific signal when subjected, simultaneously or not, to one or more external sources of excitation. Automatic signal detection allows for document authentication, if necessary. These security features include, for example, tracers in the form of active materials, particles or particle aggregates, or fibers, capable of generating a specific signal when subjected to optronic, electrical, magnetic, or electromagnetic excitation. These are referred to as third-level security features.

[0063] The additional security element(s) present within the paper according to the invention or the security document according to the invention may have first, second or third level security characteristics.

[0064] The safety feature or at least one of the features may be as described in international application WO2014033658. It may include at least one polymer derived from bio-based material.

[0065] The safety document may include information related to the bio-based content of the substrate and / or the cover layer(s). This information can be useful during an identification or authentication step, for example, by providing a reference value against which the analysis result is compared.

[0066] The safety document may include information indicating the location of a window in which the substrate is alone. This information may be a pattern or distinctive mark visible on the safety document, particularly at the edge of the window.

[0067] The safety document may include a detachable section, particularly for analysis. This section may be part of the substrate within the window.

[0068] Authentication method

[0069] The invention also meets this need by means of a method of authentication or identification of a secure document, in particular as described above comprising the detection of the presence of a polymer produced at least partially with at least one bio-based material composing the substrate by detection of the carbon isotope 14 according to one of the aforementioned standards.

[0070] Identification in the window

[0071] The authentication or identification method may involve identifying a window on the security document. This identification can be done by identifying a transparent area of ​​the security document and / or a specific pattern or symbol on the security document.

[0072] The authentication or identification method may involve extracting a sample from the window, in particular by cutting out a portion of the security document from the window.

[0073] The presence of a polymer produced at least partially with at least one bio-based material can be detected on a sample of the safety document extracted from the viewing window. This detection is carried out using the methods prescribed in the aforementioned standards. It may involve burning the sample, then converting the CO2 produced by the combustion into graphite, and finally analyzing the carbon-14 isotope content in the resulting ash. This makes it possible to obtain a sample consisting solely of the substrate and to assess the bio-based material content in the substrate alone, without contamination from other elements or layers of the safety document. Indeed, if such an analysis were to be performed outside the viewing window, it would be impossible to determine whether the identified bio-based material originates from the substrate or from another layer of the safety document.

[0074] The authentication method may include detecting the bio-based content according to one of the aforementioned standards and comparing it to reference information to deduce authenticity or identity information for the security document, at least based on this comparison. The invention may also allow for document authentication through its substrate by means of precise analysis of the percentage of compounds derived from renewable plant resources, present in the substrate, that carry the isotope. 14C. It is indeed possible to use different polymers, which may have varying bio-based content, or a mixture of polymers in chosen proportions, to obtain a predetermined bio-based content that constitutes the reference information. The correlation between the bio-based content and the reference information can allow for at least partial verification or identification of the safety document.

[0075] Identification outside the window

[0076] The method may also include the detection of bio-based pigments in the coating layer(s).

[0077] The authentication or identification method may involve extracting a sample from outside the window, in particular by cutting out a portion of the security document from outside the window, in particular in a predetermined area which may be identified by a mark or special sign visible on the security document.

[0078] The authentication method may involve detecting the bio-based material content in the sample outside the window, according to the aforementioned standards, and comparing it to the content determined within the window to deduce authenticity or identity information. This can determine that the cover layer(s) are at least partially composed of a bio-based material. It can also identify a difference in bio-based material content corresponding to a reference value and thus deduce authenticity or identity information for the safety document.

[0079] The method may include the search and / or analysis, in the sample outside the window, of one or more markers representative of the presence, content and / or a morphological characteristic of a pigment of bio-based origin, in particular of a calcium carbonate filler of bio-based origin, and the determination of the identity and / or authenticity of the safety article based at least on the comparison of the marker(s) with one or more reference information.

[0080] The marker(s) may include one or more markers representative of one or more morphological characteristics of bio-based pigments, for example, pigments derived from the grinding and / or micronization of eggshells and / or shells and / or a type of bio-based calcium carbonate, particularly eggshells from a specific bird species or shells from a specific mollusk species. The identification and / or analysis of markers representing morphological characteristics can be performed by microscopy, including electron microscopy, with or without prior incineration. This allows for the precise determination of the calcium carbonate charge's morphology and the establishment of its identity or authenticity against reference data.By "type of bio-sourced calcium carbonate", here and throughout the description below, is understood a bio-sourced calcium carbonate from a source selected from eggshell powder or shell powder or eggshell powder from a particular bird or family of birds, for example from chickens, ducks, quail, pheasants, turkeys, ostriches, geese, pigeons and / or guinea fowl, or shell powder from a particular mollusc or family of molluscs, for example from oysters, mussels, scallops, sea almonds, periwinkles, cockles, whelks, clams, cockles, razor clams, abalone, clams, limpets, queen scallops, carpet shells and / or tellins.

[0081] The marker(s) may include one or more representative markers:

[0082] - a stratified structure of calcium carbonate, characteristic of the morphological structure of calcium carbonate from shells, and / or

[0083] - of a porous and / or permeable structure, in particular comprising channels crossing the particles of the bio-based calcium carbonate charge, characteristic of the morphological structure of calcium carbonate from eggshells.

[0084] In the case of one or more markers representing a stratified structure, the marker(s) may include one or more morphological characteristics of the stratified structure, notably the average density of strata and / or the average thickness of strata. Each type of shellfish has a stratified structure with its own specific characteristics. Determining the significant morphological characteristics of shellfish types allows for the identification of the shellfish type from which all or part of the load originates. The marker(s) can distinguish the shells of oysters, mussels, scallops, clams, periwinkles, cockles, whelks, clams, razor clams, abalone, palourdes, limpets, queen scallops, carpet shells, or tellins, and more specifically, the shells of scallops, oysters, or mussels.

[0085] In the case of one or more markers representative of a porous and / or permeable structure, the marker(s) may include one or more characteristics of the porous structure, including porosity, pore shape, average pore size, and / or pore density per unit area on a given plane. Each type of bird lays eggs with shells exhibiting a porous structure with its own specific characteristics. The marker(s) can be used to distinguish eggshell powders from different birds, including chickens, quail, pheasants, turkeys, ostriches, geese, pigeons, or guinea fowl. One or more markers representative of the presence of eggshell powder may be the presence of a porous structure with an average pore diameter, measured in particular by analyzing one or more images of the safety element or ash, between 20 nm and 500 nm, preferably between 40 nm and 400 nm.

[0086] The method may include the determination of the bio-based material content determined in the sample from the window of the safety document and of one or more markers representative of one or more morphological characteristics of the pigments of bio-based origin determined in the sample from an area outside the window of the safety document and the determination of authenticity or identity information based on the combination of these two pieces of information.

[0087] The method may include determining the content of bio-based material determined in the sample from the window of the safety document and detecting the content of bio-based material according to the aforementioned standards in the sample outside the window and / or determining one or more markers representative of one or more morphological characteristics of pigments of bio-based origin determined in the sample outside the window, comparing these determinations with corresponding reference information and determining authenticity or identity information based on the combination of this information.

[0088] We can also check for the presence on the item of one or more additional conventional security features as described above.

[0089] Other types of additional security features require more sophisticated detection devices. These features, for example, are capable of generating a specific signal when subjected, simultaneously or not, to one or more external sources of excitation. Automatic signal detection allows for document authentication, if necessary. These security features include, for example, tracers in the form of active materials, particles or particle aggregates, or fibers, capable of generating a specific signal when subjected to optronic, electrical, magnetic, or electromagnetic excitation. These are referred to as third-level security features.The additional security element(s) present within the paper according to the invention or the security document according to the invention may have first, second or third level security characteristics.

[0090] The analysis of the safety document is preferably performed by automated image analysis, for example, using a computer connected to the microscope used for the analysis. The analysis can be carried out using an image analysis algorithm, specifically a machine learning algorithm trained on images of identified and / or authentic reference articles. The process can confirm identity and / or authenticity by comparing the acquired image(s) with images acquired through another test on an identified and / or authentic reference article or part thereof.

[0091] Brief description of the drawings

[0092] The invention will be better understood upon reading the detailed description that follows, the non-limiting examples of its implementation, and upon examination of the attached drawing, on which:

[0093] [Fig 1] schematically represents an example of a security document,

[0094] [Fig 2] schematically represents, in cross-section at the window level, the security document of figure 1,

[0095] [Fig 3] schematically represents, in cross-section at the window level, a variant of a security document, and

[0096] [Fig 4] is a block diagram representing the steps of the authentication or identification method of the security document in Figure 1.

[0097] Detailed description

[0098] Figures 1 and 2 illustrate a security document 10 comprising a non-opaque substrate 11 partially covered by one or more, in this case several, opacifying coating layers 12, 13, and 14. The opacifying coating layers 12, 13, and 14 at least partially cover the substrate and provide at least one window 20 in which the substrate is free of an opacifying coating layer. The substrate may be the only component present in the window, as illustrated. This is preferred. However, the presence of a total or partial layer with a small weight contribution is also possible. The important point is that the main contribution of material to the window is primarily that of the substrate. The security document 10 is, for example, a banknote and may have a rectangular shape.The safety document 10 includes, in the cover layers 12, 13 and 14, a window 20 formed by an area devoid of the cover layers 12, 13 and 14 in which only the substrate 11 appears.

[0099] The substrate 11 is a polymer or a mixture of polymers, each produced at least partially with at least one bio-based material. However, it could be otherwise. The substrate could be a mixture of one or more polymers produced at least partially with at least one bio-based material and one or more polymers derived from petroleum resources.

[0100] Preferably, the substrate 11 is transparent and free from any pigments or paper fibers. The bio-based material may be a renewable and / or biodegradable plant material or a mixture of renewable and / or biodegradable plant materials, for example, plant waste or used industrial cooking oils. The polymer may be selected from polyamide (PA), polyundecanamide (PAU), polyethylene terephthalate (PET), polyethylene furanoate (PEF), polybutylene succinate, polyhydroxy alkanoate, polypropylene (PP), including biaxially oriented polypropylene (BoPP), polylactic acid (PLA), cellulose diacetate (CDA), cellophane films, and mixtures thereof. The substrate 11 may comprise a polymer made up of more than 20% by mass, better more than 50% by mass, even better more than 70% by mass, even better more than 80% by mass of bio-based material or be entirely made up of bio-based material.

[0101] In the example shown in Figure 2, the substrate 11 is single-layered. However, it could be multi-layered, as illustrated in Figure 3. In Figure 3, the substrate 11 comprises a core layer 11c and two skin layers l lp, each extending from one side of the core layer 11c. All three layers are made of a polymer at least partially derived from bio-based material, in particular the same polymer. The skin layers l lp may have undergone treatment, including treatment facilitating adhesion of the overlay layer(s) and / or printing, for example, corona treatment. Despite the treatments and the multi-layered structure, the substrate 11 preferably remains transparent. In the example shown, the overlay layers 12, 13, and 14 may include an opacifying layer 12, an imprint 13, and a varnish 14. The opacifying layer 12 may be pigmented. It may include pigments and a binder.

[0102] The pigments may be of bio-based origin. They may contain a charge of calcium carbonate of bio-based origin, in particular chosen from the eggshell powders of various birds, including chickens, quails, pheasants, turkeys, ostriches, geese, pigeons or guinea fowl, or shells, including oyster, mussel, scallop, sea almond, periwinkle, cockle, whelk, clam, cockle, razor clam, abalone, clam, limpet, queen scallop, cockle or tellin shells, more particularly scallop, oyster, mussel shells, or mixtures thereof. Bio-based calcium carbonate pigments can be obtained from the grinding and / or micronization of a single type of bio-based calcium carbonate, in particular from eggshells of a single species of bird or shells of a single type of mollusc.Alternatively, the bio-based calcium carbonate feedstock may comprise a mixture of at least two different types of bio-based calcium carbonate. These different types of bio-based calcium carbonate are distinguished by their morphological characteristics.

[0103] The binder can be a UV crosslinking resin, a solvent-based or aqueous resin, latex, or a dispersion resin and can be at least partially of bio-based origin, in particular more than 30% by mass, better more than 50% by mass of bio-based origin.

[0104] The bio-based material content of the pigment opacifying layer, determined according to the aforementioned standards, may be greater than 1%, better greater than or equal to 2%, even better greater than or equal to 10%, even better greater than or equal to 50% or greater than 90%.

[0105] Print 13 can be formed from pigments of bio-based origin as described for the opacifying layer.

[0106] One or more of the cover layers 12, 13 and 14 may exhibit antimicrobial properties, including containing silver phosphate glass particles.

[0107] Safety document 10 may include information related to the bio-based content of the substrate 11 and / or the cover layers 12, 13 or 14 and / or to the morphological characteristics of the pigments in the cover layer(s) 12, 13 or 14.

[0108] The safety document 10 may include information indicating the location of the window 20 in which the substrate 11 is alone. This information may be a pattern or distinctive mark visible on the safety document, particularly at the edge of the window. Alternatively, there may be no marking indicating the location, and the window's position may be identified by any means, including by identifying the transparent area on the document 10 corresponding to the window 20.

[0109] The safety document may include a detachable or cut-out sample portion 22 within the window 20 and / or a detachable or cut-out sample portion 23 outside the window 20. These detachable or cut-out portions may be used for the analysis of bio-based material content as described below.

[0110] Security document 10 may also include an additional security element 25 of the first, second or third level.

[0111] The additional security element 25 may, in the example considered, take the form of a security wire, a security fiber, a particle or particle aggregate, a security board, a security foil, a data protection film, a security patch, or a security print. Preferably, the additional security element is located on a well-defined part of the security document. It may be integrated into the substrate 11 either in bulk or as a window, be affixed directly or indirectly to the security substrate, or be formed from a portion of the security document.

[0112] The block diagram in Figure 4 represents the steps of an example method for identifying and / or authenticating the security document from the previous figures.

[0113] First, in order to proceed with the analysis of the security article, including the security element, in a first step 100, a sample 22 is extracted from the window 20.

[0114] In a second step 110, sample 22 is analyzed by a destructive method to precisely quantify the bio-based content. The measurement is carried out according to ASTM D6866: Determining the Biobased Content of Solid, Liquid, and Gaseous Samples Using Radiocarbon Analysis. This standard allows the bio-based content to be obtained from the quantification of the carbon-14 isotope ( 14C) Optionally, in a step 120, a sample 23 is extracted from the window 20, and then, in a step 125, the sample 23 is analyzed. The analysis may be carried out by a destructive method to precisely quantify the bio-based content of the sample 23 and / or by searching, in particular by microscopy, for one or more morphological characteristics of pigments, in particular of a calcium carbonate charge of bio-based origin, in particular representative of a predetermined type or mixture of predetermined type of bio-based calcium carbonate.

[0115] The morphological characteristic(s) may be one or more crystallographic, ultrastructural, shape, and / or porosity characteristics of the pigments. The morphological characteristic(s) may include:

[0116] - a stratified structure of calcium carbonate, characteristic of the morphological structure of calcium carbonate from shells, easily identifiable in microscopy images in particular, and / or

[0117] - a porous structure, characteristic of the morphological structure of calcium carbonate from eggshells, easily identifiable on microscopy images in particular.

[0118] In the case of a stratified structure, the morphological characteristic(s) may include one or more characteristics of the stratified structure, notably the average density of strata and / or the average thickness of strata. Each shellfish type has a stratified structure with its own specific characteristics. Determining the significant morphological characteristics of shellfish types allows for the identification of the shellfish type from which all or part of the haul originates. The morphological characteristic(s) can distinguish the shells of oysters, mussels, scallops, clams, periwinkles, cockles, whelks, clams, razor clams, abalone, palourdes, limpets, queen scallops, carpet shells, or tellins, and more specifically, the shells of scallops, oysters, or mussels.

[0119] In the case of a porous structure, the morphological characteristic(s) may include one or more features of the porous structure, notably porosity, pore shape, average pore size, and / or pore density per unit area on a given plane. Each type of bird lays eggs with shells exhibiting a porous structure with its own specific characteristics. The morphological characteristic(s) can be used to distinguish eggshell powders from different birds, including chickens, quail, pheasants, turkeys, ostriches, geese, pigeons, or guinea fowl. The morphological characteristic(s) representative of the presence of eggshell powder may be the presence of a porous structure with an average pore diameter, measured particularly by image analysis of the powder, between 20 nm and 500 nm, ideally between 40 nm and 400 nm.

[0120] In the case of research or analysis of morphological characteristics, this can be done with or without prior incineration, notably by visualization under a microscope, electron or otherwise. The analysis of morphological characteristics can be carried out by image acquisition, particularly with an electron or optical microscope, at a magnification allowing visualization of the calcium carbonate grains, and by analyzing the acquired images, notably using a computer image analysis algorithm.

[0121] Step 130 may involve determining authenticity or identity information based, at least, on the bio-based content determined in sample 22, particularly by comparison with a reference bio-based content. Indeed, not all polymers derived at least partially from bio-based materials necessarily have the same bio-based content, and it is possible to adjust this content by the proportion of bio-based polymers in the substrate. It is thus possible to have a specific reference content to authenticate or identify a safety document. The table below provides examples of the bio-based content of several polymers.

[0122] Alternatively, or in addition, step 130 may include determining authenticity or identity information based on the information obtained from the analysis(es). Authenticity or identity can thus be determined when the measured content is substantially equal to the reference content.

[0123] Comparing the bio-based material content determined in the sample within window 20 and in the sample outside window 20 allows us to deduce a difference in content, quantify it, and compare it to a reference content of bio-based material in the cover layer(s). From this deduction, it is possible to conclude, along with other information, whether or not it provides information of authenticity or identity.

[0124] It is possible to establish authenticity or identity based on the bio-based content of the substrate in the document window and the morphological structure of the pigment(s) in the topcoat(s), optionally also including the bio-based content in topcoat(s) 12, 13, and 14. Combining these two or three pieces of information provides greater security for the safety document. In this case, the method can be based on one or more of the following reference information: the presence of bio-based calcium carbonate in the topcoat(s), a reference content of bio-based calcium carbonate in the topcoat(s), a reference mass proportion of bio-based calcium carbonate, or of one or each type of bio-based calcium carbonate in the topcoat(s).a reference morphological characteristic of bio-based calcium carbonate or of one or more types of bio-based calcium carbonate in the cover layer(s), a reference value or range of values ​​representative of a morphological characteristic of bio-based calcium carbonate or of one or more types of bio-based calcium carbonate in the cover layer(s), information on the type(s) of bio-based calcium carbonate present in a reference bio-based calcium carbonate charge in the cover layer(s), and / or the mass proportions of each type of bio-based calcium carbonate in a reference bio-based calcium carbonate charge in the cover layer(s).

[0125] Identification and / or authentication using the methods described above can be automated by a computer implementing a machine learning algorithm trained on identified and / or authentic reference articles. This allows for multi-layered security, ranging from simple determination of the bio-based material content within the window to complex composition of the bio-based material security document both within and outside the window. The invention is not limited to the examples described above. Other security features besides those mentioned can be incorporated into the security document. The substrate may contain markers of the bio-based material content, such as particles or aggregates of particles that are fluorescent or phosphorescent under a specific light.Other types of bio-based calcium carbonate than those mentioned above are possible insofar as they are identifiable and have different properties of their own from quarry calcium carbonate.

Claims

Demands 1. Safety document (10) comprising: a non-opaque polymeric substrate (11) comprising a polymer produced at least partially with at least one bio-based material, and one or more opacifying cover layers (12, 13, 14) partially covering the substrate (11) and providing at least one window (20) in which the substrate (11) is free of opacifying cover layer.

2. Document according to claim 1, wherein the bio-based material is a renewable and / or biodegradable plant material or a mixture of renewable and / or biodegradable plant materials.

3. Document according to claim 1 or 2, wherein the polymer produced at least partially with at least one bio-based material is selected from polyamide (PA), polyundecanamide (PAU), polyethylene terephthalate (PET), polyethylene furanoate (PEF), polybutylene succinate, polyhydroxy alkanoate, polypropylene (PP), in particular biaxially oriented (BoPP), polylactic acid (PL A), cellulose diacetate (CDA), cellophane films and mixtures thereof.

4. Document according to any one of the preceding claims, wherein the polymer is derived, in a proportion greater than or equal to 20% by mass, better greater than or equal to 50% by mass, even better greater than or equal to 70% by mass, even better greater than or equal to 80% by mass, from bio-based material.

5. Document according to any one of the preceding claims, wherein the substrate (11) is transparent.

6. Document according to any one of the preceding claims, wherein the substrate (11) is free of pigment and / or fillers.

7. Document according to any one of the preceding claims, wherein, in the window, the substrate is present at more than 90% by mass, better at more than 95% by mass, still better at more than 98% by mass.

8. Document according to any one of the preceding claims, comprising at least one area in the window in which only the substrate (11) is present, in particular the entire window.

9. Document according to any one of the preceding claims, wherein the or at least one of the overlay layers (12) is a pigment layer and / or the or at least one of the overlay layers (13) is an impression.

10. Document according to the preceding claim, in which the pigment layer (12) and / or the printing (13) comprise pigments of bio-based origin.

11. Document according to the preceding claim, wherein the pigments comprise calcium carbonate of bio-based origin, in particular selected from eggshell powders of various birds, in particular chickens, quails, pheasants, turkeys, ostriches, geese, pigeons or guinea fowl, or shellfish, in particular oyster, mussel, scallop, sea almond, periwinkle, cockle, whelk, clam, cockle, razor clam, abalone, clam, limpet, queen scallop, carpet shell or tellin, more particularly scallop, oyster, mussel shells, or mixtures thereof.

12. Document according to claim 10 or 11, wherein the opacifying topcoat (12) comprises bio-based pigments and a binder, the binder being at least partially bio-based, in particular more than 50%, preferably more than 55% bio-based 13. Method for authenticating or identifying a secure document, in particular according to any one of the preceding claims, comprising detecting in a window (20) of the security document the presence of a polymer produced at least partially with at least one bio-based material composing the substrate (11) by detecting the carbon isotope 14 according to ASTM D6866.

14. Method according to claim 13, comprising identifying a window (20) on the security document and extracting a sample (22) from the window, in particular by cutting a portion of the security document from the window.

15. Method according to claim 13 or 14, comprising the detection of the bio-based material content according to ASTM D6866 and the comparison to a reference information to deduce an authenticity or identity information of the safety document at least based on this comparison.

16. A method according to any one of claims 13 to 15, comprising extracting a sample (23) from the window, in particular by cutting a portion of the safety document from the window, and detecting the bio-based material content according to the ASTM D6866 standard in the sample outside the window and comparison to that determined in the window to deduce information of authenticity or identity.

17. Method according to any one of claims 13 to 16, comprising determining the content of bio-based material determined in the sample (22) from the window (20) of the safety document and of one or more markers representative of one or more morphological characteristics of the pigments of bio-based origin determined in the sample (23) from an area outside the window (20) of the safety document and determining information of authenticity or identity based on the combination of these two pieces of information.

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