Method for verifying or identifying security documents

Abstract

The present invention relates to a method for identifying and / or verifying a security document comprising a paper substrate, in which the substrate is analyzed to detect the presence of one or more markers representing the presence of one or more compounds extracted from one or more broad-leaved trees in the substrate, and information about the identity and / or authenticity of the document is generated as a function of the properties and / or proportions of the one or more markers in the substrate.

Description

Technical Field

[0001] The present invention relates to security documents and their identification or authentication.

[0002] A “security document” is a document of value, such as a means of payment (moyen de paiement) such as a banknote, cheque, bank card or restaurant voucher, an identification document such as an identity card, visa, passport or driving licence, a lottery ticket, a transport voucher (titre de transport) or a ticket for admission to a cultural or sports event. Background Art

[0003] In order to make documents secure, security elements are often used which are added to the paper when the document is manufactured.

[0004] It is therefore a well-known practice to use mineral pigments to authenticate or identify paper by giving it a specific signature. These mineral pigments are introduced during the wet stage of papermaking. They may consist of a mixture of rare earths, as described in the following publications: EP0975460, WO9938702, WO9938700, WO9939051, WO9938703, WO2004111951, WO2005035261, WO2005035271, WO2005035272, WO2005036470, WO2005036477, WO2005036478 and WO2005036479.

[0005] The use of such pigments entails a number of problems. On the one hand, their mineral nature contributes to an increase in the mineral load of the paper and thus to an increase in the ash content of the paper. In addition, an overload of mineral pigments tends to impair the mechanical strength of the paper. On the other hand, like other opaque mineral fillers (e.g. titanium dioxide), they are not completely retained during drainage and their losses in the white water are significant, and since they are sometimes very expensive markers, this can have a non-negligible economic impact. Moreover, in certain cases, their use can therefore pose environmental problems due to the toxicity inherent in their chemical nature. Finally, in order to detect them, it is often necessary to use specific high-tech electromagnetic detectors, which complicates the authentication of the documents.

[0006] Furthermore, it is also known to use microscopic observation techniques to identify and quantify specific synthetic or natural fibers in paper substrates. Publications WO2015 / 200575, WO2015 / 200577 and WO2015 / 200572 describe such methods. In some cases, especially when they are mixed with other fibers such as cotton fibers, paper refining operations can make the identification of these "special" fibers very difficult and require analysis by experienced operators. This difficulty is exacerbated by the similarity in fiber properties between specific substances and other fiber components of paper (they have an elongated shape).

[0007] There is a need to further increase the security of documents, in particular by simplifying their authentication and / or their identification. Summary of the invention Brief description of the invention

[0008] The present invention aims to meet this need and, according to one of its aspects, is achieved by means of a method for identifying and / or authenticating a security document comprising a paper substrate, wherein the substrate is analyzed to detect the presence of one or more markers representing the presence in the substrate of one or more compounds extracted from one or more broadleaf trees (feuillu(s)), and information about the identity and / or authenticity of the document is generated as a function of the properties and / or proportions of said one or more markers in the substrate.

[0009] "Compounds extracted from one or more broadleaf trees" include fibers and vaisseaux of cellulose and hemicellulose. Vaisseaux and fibers differ in their size. Fibers are generally longer and thinner than vaisseaux. The compound may be a solid compound. The compound may be introduced in the form of pulp. Fibers of broadleaf trees are generally short and not too thick. Fibers and vaisseaux contain cellulose or hemicellulose.

[0010] "Broadleaved trees" refer to trees that produce fully expanded leaves, as opposed to coniferous or needle-leaved trees (résineux). Broadleaved trees may shed their leaves periodically, especially in the fall, which is why they are called deciduous trees. The leaves of broadleaved trees are usually large. Unlike broadleaved trees, needle-leaved trees have needle-shaped leaves that are gradually renewed, which is why they are called evergreen. Therefore, coniferous trees always have the same appearance. Needle-leaved trees may also be called conifers. The following trees are examples of broadleaved trees: birch, charmeuse, chestnut, oak, eucalyptus, beech, liquidambar styracifere, purple tree, poplar, tulip tree (tulipier d'Amérique).

[0011] The benefit of using compounds extracted from broadleaf trees in paper substrates is twofold. On the one hand, compounds extracted from broadleaf trees are very suitable for manufacturing paper substrates due to the properties of their cellulose fibers. The paper substrate obtained therefore has good mechanical strength. On the other hand, the marker representing the presence of one or more compounds extracted from one or more broadleaf trees in the substrate is an easily recognizable marker. Identification and / or verification can be carried out without difficulty, in particular by visual observation under low magnification.

[0012] Furthermore, the method of the invention has the advantage of being harmless to health and the environment compared to the use of certain mineral pigments. Thus, it does not require the detection of non-natural markers that may be toxic and / or harmful to the environment.

[0013] The process according to the invention is economical since it requires the use of compounds extracted from broad-leaved trees, which are widely distributed trees.

[0014] The paper substrate may comprise cellulose fibres other than hardwood fibres. In particular, the substrate may comprise cotton fibres, particularly when used to produce banknotes.

[0015] The nature and / or proportion of one or more compounds extracted from one or more hardwood trees in the composition of the substrate may be varied to produce a security document having a unique signature. For example, compounds extracted from two different hardwood trees may be mixed to produce a paper substrate, and such a substrate may be distinguished from another substrate containing, for example, different proportions of the same compound or other compounds extracted from one or more hardwood trees.

[0016] The analysis of the substrate can be carried out with and / or without magnification, in particular with the naked eye, for example after a specific staining. The analysis of the substrate under magnification is preferably carried out using a microscope. The analysis of the substrate is preferably carried out without special electromagnetic detectors, for example under white light.

[0017] The method according to the invention thus has the advantage of being easy to implement. It does not require any equipment other than an optical microscope to detect the marker. Its implementation is thus economical and rapid.

[0018] The one or more markers representing the presence of one or more compounds extracted from one or more hardwood trees in the substrate can also be detected without amplification. Thus, the security document can be authenticated and / or identified by an uninformed observer ("the common man").

[0019] The one or more broad-leaved trees whose presence is to be sought in the paper preferably consist of at least one of the following species: birch, bergamot, chestnut, oak, eucalyptus, beech, styrax, tupelo, poplar, tulip tree.

[0020] The one or more broad-leaved trees preferably belong to the family Eucalyptus. In particular, they consist of at least one of the following eucalyptus species: eucalyptus globulus, eucalyptus camaldulensis, eucalyptus rostrata, eucalyptus citriodora, eucalyptus cordata, eucalyptus deglupta, eucalyptus gundal, eucalyptus gunnii, eucalyptus pauciflora, eucalyptus radiata, eucalyptus regnans, eucalyptus sideroxylon.

[0021] Eucalyptus trees have the advantage of being fast growing trees which can be easily produced all over the world. They therefore constitute a readily accessible resource for making paper substrates.

[0022] Preferably, at least one of the markers is composed of vessels of a broadleaved tree. In particular, at least one of the markers is composed of vessels of a eucalyptus tree.

[0023] Vessels of hardwood trees have the advantage of having an easily identifiable morphology, which allows the fibers of compounds extracted from hardwood trees to be distinguished from cotton fibers when analyzing the substrate.

[0024] Furthermore, their morphology has the advantage of giving them a large specific surface area, which facilitates their retention, in particular retention without loss, during the manufacture of paper substrates. Thus, conduits of compounds extracted from hardwood trees can contribute to the mechanical reinforcement of paper substrates, just as hardwood and cotton fibers do.

[0025] Due to their organic and cellulosic composition, these conduits have no significant impact on ash production.

[0026] The method according to the invention preferably comprises analysing the shape of the catheter. Information about the identity and / or authenticity of the document may be generated based at least on the result of the analysis.

[0027] When analyzing the catheter shape, preferably at least the ratio of the catheter length to the catheter width is calculated.

[0028] During the analysis, it is preferably determined whether the ratio is between 0.7 and 4.5, better between 0.8 and 4 (especially for eucalyptus), even better between 0.9 and 3.5, still better between 1 and 3, still better between 1.1 and 2.5, still better between 1.2 and 2, for example about 1.8.

[0029] The length of the conduits, in particular eucalyptus conduits, is preferably between 100 and 550 μm, even more preferably between 120 and 500 μm, even more preferably between 150 and 450 μm, even more preferably between 200 and 350 μm, for example about 290 μm.

[0030] The width of the conduits, in particular of eucalyptus conduits, is preferably between 50 and 400 μm, even more preferably between 75 and 350 μm, even more preferably between 100 and 300 μm, even more preferably between 100 and 250 μm, for example about 160 μm.

[0031] When carrying out the method according to the invention, preferably conduits having a substantially rectangular cross section are counted.

[0032] The cross-section of the vessels of broadleaf trees, especially eucalyptus vessels, has a substantially rectangular, even square shape. They are also quite thick and quite short. Therefore, they are very different from the elongated conventional cotton fibers. Therefore, they are easy to count during the substrate analysis.

[0033] For analysis, the substrate may be contacted with a substance suitable for selectively coloring at least one of the markers. This selective coloring may occur before counting the catheters. The substance may be specifically selected to color catheters and fibers, particularly cotton fibers, differently.

[0034] This selective coloring makes it easier to identify markers, in particular catheters. After coloring, they can thus be identified with or without magnification.

[0035] The substance suitable for selectively coloring at least one of the markers is preferably a Herzberg reagent solution.

[0036] On a substrate consisting essentially of cotton fibers and one or more compounds extracted from one or more hardwood trees, the use of Herzberg's reagent (or zinc iodide) enables the one or more compounds extracted from one or more hardwood trees to be colored a first color, such as blue, and the cotton fibers to be colored a second color, such as red, different from the first color.

[0037] The element having the first color is visible without magnification, which enables the detection of the presence of one or more compounds extracted from one or more hardwood trees. Thus, the specific coloration allows initial verification and / or identification with the naked eye.

[0038] A more thorough magnification analysis can then be carried out, for example under a microscope. The aim is to analyse the morphology of the markers (e.g. vessels) to determine the type of broadleaf tree used. Eucalyptus vessels are particularly easy to identify due to their very characteristic morphology.

[0039] During the analysis, the colored markers are preferably counted.

[0040] Preferably, the markers are counted over a given surface area of ​​the substrate being analyzed and the proportion of compounds extracted from one or more hardwood trees in the pulp used to make the substrate is inferred.

[0041] The one or more markers preferably appear alone. They can be directly identified on the surface of the paper substrate with or without magnification. It is therefore not necessary to shred and / or disassemble the security document to analyze it.

[0042] The analysis of the substrate is therefore preferably carried out without destroying the document. For example, no sample is extracted from the document. During this analysis, the one or more markers analyzed may be present on the document. In the case of banknotes, they are examined, for example, under a microscope to determine the presence and / or content of the marker.

[0043] At least one of the markers used to implement the identification and / or authentication method according to the invention may be present in a small number ratio relative to other components extracted from hardwood trees and present in the paper. For example, in the case where the marker consists of vessels, the hardwood tree compound incorporated into the paper during papermaking may have 10 times fewer vessels than fibers, preferably 50 times fewer vessels than fibers, preferably 100 times fewer vessels than fibers, or even 1000 times fewer vessels than fibers. Safety factor

[0044] The presence of one or more additional traditional security elements on the document may also be verified.

[0045] Among these additional security elements, some are detectable by eye in daylight or artificial light, without the use of any special equipment. These security elements include, for example, colored fibers or planchettes, fully or partially metallized or printed security threads, security knitted structures, security films, watermarks, optically variable elements (so-called "OVDs"), and in particular holograms. These security elements are called first-level security elements.

[0046] Other types of additional security elements can only be detected with the aid of relatively simple equipment, such as lamps emitting in the ultraviolet (UV) or infrared (IR) range. These security elements include, for example, fibers, small plates, strips, threads or particles. These security elements may be visible or invisible to the naked eye, for example glowing under the illumination of a Wood's lamp, which emits at a wavelength of 365nm. These security elements are called second-level security elements.

[0047] Other types of additional security elements require more complex detection equipment to detect them. These security elements are capable of generating specific signals, for example, when subjected to one or more external excitation sources in a simultaneous or non-simultaneous manner. Automatic detection of the signal enables verification of the document when necessary. These security elements include, for example, tracers in the form of active materials, particles or fibers, which are capable of generating specific signals when they are subjected to optoelectronic, electrical, magnetic or electromagnetic excitation. These security elements are called third-level security elements.

[0048] The additional security element or elements present in the security document according to the invention or in the paper according to the invention may have primary, secondary or tertiary security properties.

[0049] The analysis of the substrate is preferably performed by automated image analysis, for example using a computer, in particular a computer connected to an optical microscope for the analysis. Security Documents

[0050] The present invention also relates, independently or in combination with the above, to a security document comprising a paper substrate comprising cellulose fibres and one or more compounds extracted from one or more hardwood trees.

[0051] The addition of a compound extracted from one or more broadleaf trees to the composition of the paper substrate of a security document makes it possible to increase the mechanical strength of the paper. The fiber and cellulose properties of the compound extracted from broadleaf trees contribute to the development of the mechanical strength of the paper substrate. The internal bonding strength and the dry and wet tensile strength of the security document according to the invention are improved by the presence of the compound extracted from broadleaf trees. Thus, the durability level of the paper is improved, which makes it possible to increase the length of time that the security document is in circulation, in particular in the case of banknotes.

[0052] Hardwood wood fibers, especially eucalyptus fibers, have the advantage of being short and not too thick. They also have a large specific surface area, especially compared to the cotton fibers traditionally used to make paper substrates.

[0053] The substrate preferably contains 2-50%, better still 3-40%, better still 5-30% by mass of one or more compounds extracted from one or more broadleaf trees relative to the mass of the substrate. The weighing of the substrate is preferably carried out at ambient temperature (20° C.) at a relative humidity of 50%.

[0054] The substrate may in particular comprise 0.1 to 1% per unit surface area of ​​a broadleaf tree, in particular eucalyptus.

[0055] The substrate may comprise at least 50% by mass of cotton fibers, relative to the total mass of the substrate.

[0056] The one or more broadleaved trees preferably belong to the Eucalyptus family and may be chosen in particular from the following eucalyptus species: eucalyptus globulus, eucalyptus camaldulensis, eucalyptus rostrata, eucalyptus citrifolia, eucalyptus serrata ... gundal, eucalyptus malariae, eucalyptus frutescens, eucalyptus radiata, eucalyptus regia, eucalyptus rubra.

[0057] Compounds extracted from eucalyptus have the advantage of containing hemicellulose which, due to the reactivity of its carboxyl groups, allows active cooperation with resins, in particular polyamide-polyamine-epichlorohydrin resins (PAAE resins), which improves the development of wet strength of the paper substrate.

[0058] The substrate may thus advantageously comprise both compounds extracted from eucalyptus, in particular the fibres and vessels of eucalyptus, and a resin which imparts wet strength to the paper, preferably a PAAE resin.

[0059] One or more security elements may be integrated or added to the substrate, this or these security elements being first-level, second-level and / or tertiary security elements, as described in detail above, and which are, for example, selected from: security threads, platelets, security films, watermarks, optically variable elements (so-called "OVDs"), in particular holograms, tracers in the form of materials capable of generating a specific signal when subjected to electrical, magnetic or electromagnetic (in particular optical) excitation, such as UV or IR luminescent agents, intaglio printing or optically variable inks.

[0060] In an example of an embodiment, the substrate comprises compounds extracted from at least two different hardwood species, in particular, on the one hand, eucalyptus and on the other hand, a hardwood selected from the group consisting of birch, elm, chestnut, oak, beech, styrax, tupelo, poplar, tulip tree. BRIEF DESCRIPTION OF THE DRAWINGS

[0061] The invention may be more clearly understood by reading the following description of a non-limiting example of embodiment and by consulting the accompanying drawings, in which:

[0062] [ Figure 1 ] Figure 1is a schematic diagram of an example of a security document according to the present invention,

[0063] [ Figure 2 ] Figure 2 is a flowchart of steps for an example of an identification and / or authentication method,

[0064] [ Figure 3 ] Figure 3 is a microscopic view of a substrate containing a selectively colored compound extracted from a hardwood tree,

[0065] [ Figure 4 ] Figure 4 is similar to Figure 3 View,

[0066] [ Figure 5 ] Figure 5 are photographs of four substrates containing increasing proportions of compounds extracted from hardwood trees after selective coloration of vessels and entourage for counting. DETAILED DESCRIPTION Detailed description

[0067] Figure 1 A security document 10 is shown comprising a substrate 11 in which a security element 12 is integrated or affixed to the substrate 11 .

[0068] The substrate 11 is fibrous. It may contain fibers and additives commonly used in the paper industry, in particular cellulose fibers. The substrate may contain a mixture of long cellulose fibers and short cellulose fibers. The substrate 11 contains one or more compounds extracted from broad-leaved trees, i.e., fibers and vessels of broad-leaved trees.

[0069] The substrate may comprise a single fiber layer, or a plurality of fiber layers (also referred to as "jets") that are assembled after forming, especially in the wet phase.

[0070] The substrate may comprise one or more security structures obtained during the manufacturing process, and the substrate may in particular comprise a fibrous layer carrying a watermark.

[0071] The one or more fibrous layers of the substrate may be produced on a flat bed or circular paper machine, and the one or more watermarks may be produced in the wet section using conventional methods known to those skilled in the art.

[0072] At least one fiber layer of the substrate or even the substrate itself may have a fiber content of 60-120 g / m 2 , preferably 70-90g / m 2 of grammage (according to standard ISO 536).

[0073] At least one fiber layer of the substrate or even the substrate itself may have a thickness of 60-120 μm, preferably 70-110 μm, for example approximately 110 μm (according to standard ISO 534).

[0074] Figure 2 The block diagram in shows the steps of an example of an identification and / or authentication method according to the present invention.

[0075] First, in order to carry out the analysis of the security document, in a first step E1, the document is immersed in a solution of Herzberg reagent. This first step E1 allows the selective staining of the desired markers.

[0076] Then, in a second step E2, the document is allowed to dry. Once the document is dry, it can be observed using an optical microscope (step E3).

[0077] The presence of compounds extracted from hardwood trees was sought in the base material of the document.

[0078] By observing the morphology of the detected markers, it is possible to determine the nature of the broadleaf trees used in the composition of the substrate. This allows an initial identification of the file.

[0079] The number of colored markers within a given surface area of ​​the document is then counted using a microscope (step E4). From this count, the mass percentage of compounds extracted from hardwood trees in the composition of the substrate of the document can be estimated. This estimation enables the identification of the document.

[0080] After the analysis, in particular after the counting, information about the identity and / or authenticity of the document can be generated (step E5 ).

[0081] exist Figure 3-5 In an example of the invention, the marker representing the presence of one or more compounds extracted from one or more hardwood trees in the paper substrate is eucalyptus vessels.

[0082] Figure 3-5 The substrate shown in Figure 1 was selectively colored by immersion in a solution of Herzberg's reagent. The compounds extracted from the hardwood tree (i.e., the vessels and fibers) were thus colored blue and could be distinguished from the other elements of the substrate.

[0083] Depend on Figure 3 It can be seen that the eucalyptus conduits 1 differ from the eucalyptus fibers 2 in that they are wider and shorter in shape.

[0084] The length L and width l of the eucalyptus duct are as follows Figure 4 As shown, the length L is, for example, about 290 μm, and the width l is, for example, about 160 μm.

[0085] Figure 5Four substrates are shown, wherein from left to right, the mass proportion of compounds extracted from eucalyptus gradually increases. Substrate S1 comprises 5 mass% eucalyptus pulp, substrate S2 comprises 10 mass% eucalyptus pulp, substrate S3 comprises 20 mass% eucalyptus pulp, and substrate S4 comprises 30 mass% eucalyptus pulp.

[0086] Selective staining of eucalyptus vessel 1 using Herzberg reagent. From this photo, it can be seen that the greater the mass proportion of the compound extracted from eucalyptus in the substrate, the greater the number of vessels. This correlation is also established in Examples 2 and 3 below. Example

[0087] Example 1

[0088] The effect of introducing 5, 10, 20 and 30 mass % of eucalyptus pulp relative to the total mass of pulp as a replacement for a portion of the cotton pulp (Cotton 1, Cotton 2) on the mechanical properties of the paper substrate was evaluated.

[0089] The obtained substrate is surface treated in a size press.

[0090] A substrate comprising only cotton fibers without the compound extracted from eucalyptus was used as a control.

[0091] The zeta potential was measured using a Mütek SZP-06 "System Zeta Potential" apparatus from BTG.

[0092] To assess the dry tensile strength, in particular the dry breaking length, the length at which the sheet breaks under its own weight can be measured according to standard ISO 1924-2.

[0093] To evaluate the wet tensile strength, in particular the wet breaking length, the length at which the sheet breaks under its own weight can be measured according to standard ISO 3781.

[0094] The wet strength (REH) is defined as the ratio of the wet breaking length to the dry breaking length according to the following formula:

[0095] [Math 1]

[0096]

[0097] The internal bond strength (delamination strength) was measured using a SCOTT device (model B, No ES033) according to standard Tappi 569om-09.

[0098] The evaluation results are shown in the following table: The percentages of cotton 1, cotton 2 and eucalyptus pulp are mass percentages relative to the total mass of the pulp. [Table 1]

[0099] In the above table: "MD" means "machine direction", "CD" means "cross direction" and "Moy." means "mean".

[0100] It can be seen that the internal bond strength, dry tensile strength and wet tensile strength of the substrate comprising eucalyptus are superior to the control substrate comprising only cotton fibers.

[0101] The Zeta potential (ZP) of the substrate was also measured. It can be seen that when the eucalyptus content reaches 10%, 20% and 30% (by mass), it gradually changes from 2.2mv to -3.2mv, -5.3mv and -10.5mv, respectively. This reflects the increasing presence of related hemicelluloses derived from eucalyptus, thereby enhancing the binding potential of PAAE resin.

[0102] Comparing a substrate containing 20 mass % of a compound extracted from eucalyptus with a control substrate not containing any compound extracted from eucalyptus, it was found that the internal bonding strength of the substrate containing eucalyptus was improved by 33.2%, the stiffness was improved by 23.1%, the dry tensile value was improved by 5%, and the wet tensile value was improved by 14.5%.

[0103] Therefore, the introduction of compounds extracted from eucalyptus into the substrate can indeed improve the mechanical strength of this substrate.

[0104] Furthermore, the above results indicate that the presence of eucalyptus fibers does not excessively alter the color of paper used for security documents.

[0105] Example 2

[0106] In this example, the objective was to count the eucalyptus ducts on paper substrates containing compounds extracted from eucalyptus in different mass proportions by direct observation of the substrate (i.e., without the use of a microscope). The substrate analyzed comprised cotton pulp comprising two different grades of cotton fibers mixed in the same mass proportion. The substrate also comprised a portion of eucalyptus pulp. The compositions of the various paper substrates used are shown in the table below. The percentages given are mass percentages. [Table 2]

[0107] Each substrate was immersed in the Herzberg reagent solution for at least 30 seconds. The area of ​​the substrate corresponding to the eucalyptus vessels was colored bluish purple. The substrate was then allowed to air dry.

[0108] The eucalyptus vessels thus coloured could be easily counted. The following table gives the count results for each substrate. [Table 3]

[0109] There was a correlation between the number of eucalyptus vessels counted and the proportion of compounds extracted from eucalyptus in the substrate. The greater the proportion of compounds extracted from eucalyptus in the substrate, the greater the number of vessels counted.

[0110] Example 3

[0111] In this example, the objective was to count the number of eucalyptus ducts on paper substrates containing different mass proportions of compounds extracted from eucalyptus. The substrate analyzed contained cotton pulp containing two different grades of cotton fibers mixed in the same mass proportion. The substrate also contained a portion of eucalyptus pulp. The compositions of the various paper substrates used are shown in the table below. The percentages given are mass percentages. [Table 4]

[0112] First, a dispersion of the substrate is prepared as follows:

[0113] 1- Cut and weigh a 4x4cm square of each substrate. Then cut this square into pieces of approximately 1x1cm. Then transfer them to the bowl of a mixer.

[0114] 2- Add 50 ml of demineralized water and then grind at maximum speed for 3 minutes.

[0115] 3- Rinse the bowl and lid of the mixer with demineralized water and transfer the obtained fiber suspension into a beaker. Then dilute it with about 200 mL of rinse water.

[0116] 4- Filter on a sieve with a 53 μm square mesh. Then rinse it and transfer it to a beaker and dilute it with about 50 mL of rinse water. This allows the removal of fillers, especially titanium dioxide (TiO2).

[0117] 5- Place the beaker in an oven at 105°C to evaporate the water and obtain a slightly moist pulp.

[0118] Slides were then prepared to count the ducts:

[0119] 1- Deposit a few drops of Herzberg's reagent on a microscope slide (26x76 mm). Using two bent dissecting needles, take a small amount of pulp and spread it in the reagent until a uniform distribution is obtained without fiber clumps (also called clots). Cover with a cover glass (24x32 cm). Prepare about ten slides in this way.

[0120] 2 - Place the slide on the stage of an optical microscope (Olympus / transmitted light / 5X objective).

[0121] 3- Using the lateral movement of the stage, move the slide so that all areas are visible without overlapping the fields of view.

[0122] 4- Count the number of eucalyptus conduits in each circular field.

[0123] The counting results are shown in the following table: [Table 5]

[0124] There is a correlation between the number of eucalyptus vessels counted and the proportion of compounds extracted from eucalyptus in the substrate. The greater the proportion of compounds extracted from eucalyptus in the substrate, the greater the number of vessels counted. Counting the number of eucalyptus vessels thus does allow an estimation of the mass proportion of eucalyptus in the composition of the substrate. This enables the identification and / or authentication of security documents made from a substrate comprising a portion of eucalyptus.

[0125] For example, a substrate is verified when the counts are a proportion of the mass of eucalyptus that corresponds to the expectation for the true substrate.

[0126] If there are multiple files with different species of hardwood, the substrate can be identified based on the nature of the hardwood used.

Claims

1. A method of identifying and / or authenticating a security document comprising a paper substrate, wherein the substrate is analyzed to detect the presence of one or more markers representing the presence in the substrate of one or more compounds extracted from one or more hardwood trees, and information about the identity and / or authenticity of the document is generated based on the properties and / or proportions of said one or more markers in the substrate.

2. The method according to the preceding claim, wherein the analysis of the substrate is carried out with and / or without magnification, in particular with the aid of the naked eye.

3. The method according to any of the preceding claims, wherein the one or more broad-leaved trees consist of at least one of the following species: birch, bergamot, chestnut, oak, eucalyptus, beech, styrax, tupelo, poplar, tulip tree, preferably eucalyptus.

4. The method according to any one of the preceding claims, wherein the one or more broadleaved trees belong to the Eucalyptus family, in particular consisting of at least one of the following eucalyptus species: eucalyptus globulus, eucalyptus camaldulensis, eucalyptus rostrata, eucalyptus citriodora, eucalyptus cordata, eucalyptus deglupta, eucalyptus gundal, eucalyptus gunnii, eucalyptus pauciflora, eucalyptus radiata, eucalyptus regnans, eucalyptus sideroxylon.

5. The method according to any of the preceding claims, at least one of the markers being constituted by a vessel of a hardwood tree.

6. Method according to the preceding claim, wherein the method comprises analyzing the shape of the catheter and said information is generated at least based on the result of this analysis.

7. Method according to the preceding claim, wherein when analyzing the shape at least the ratio of the duct length to the duct width is calculated.

8. A method according to the preceding claim, wherein during the analysis it is determined whether the ratio is between 0.7 and 4.5, better between 0.8 and 4, even better between 0.9 and 3.5, still better between 1 and 3, still better between 1.1 and 2.5, still better between 1.2 and 2, for example approximately 1.

8.

9. A method according to any one of the three immediately preceding claims, wherein conduits having a substantially rectangular cross section are counted.

10. The method according to any one of the preceding claims, wherein for the analysis the substrate is contacted with a substance suitable for selectively coloring at least one of the markers.

11. The method according to the preceding claim, wherein the substance is a Herzberg reagent solution.

12. The method according to one of the two preceding claims, wherein during the analysis, the colored markers are counted.

13. A method according to any preceding claim, wherein the analysis of the substrate is performed without destroying the document.

14. A method according to any of the preceding claims, wherein the presence of one or more security elements on the document is also verified, the one or more security elements being in particular selected from: a security thread, a platelet, a security knitted structure, a security film, a watermark, an optically variable element (OVD), in particular a hologram, a tracer in the form of a material capable of generating a specific signal when subjected to electrical, magnetic or electromagnetic excitation, in particular optical excitation.

15. The method according to any one of the preceding claims, wherein the analysis of the substrate is performed by automated image analysis.

16. Method according to any of the preceding claims, the substrate analysed comprising 2-50%, better still 3-40%, better still 5-30% by mass of one or more compounds extracted from broadleaf trees, in particular eucalyptus, preferably vessels, relative to the mass of the substrate.

17. Security document comprising a paper substrate containing 2-50%, better still 3-40%, better still 5-30% by mass, relative to the mass of the substrate, of one or more compounds extracted from broad-leaved trees, in particular eucalyptus, preferably conduits, The security document comprises one or more security elements integrated into or added to the substrate.

18. Security document according to the preceding claim, the one or more security elements being selected from: a security thread, a platelet, a security knitted structure, a security film, a watermark, an optically variable element (OVD), in particular a hologram, a tracer in the form of a material capable of generating a specific signal when subjected to electrical, magnetic or electromagnetic excitation, in particular optical excitation.

19. The security document according to any one of the two preceding claims, wherein the eucalyptus is chosen from the following eucalyptus species: eucalyptus globulus, eucalyptus camaldulensis, eucalyptus rostrata, eucalyptus citrifolia, eucalyptus serrata ... gundal, eucalyptus malus, eucalyptus frutescens, eucalyptus radiata, eucalyptus regia, eucalyptus rubrum.

20. A security document according to any one of claims 17 to 19, selected from the group consisting of: a banknote, a cheque, a bank card or a restaurant voucher, an identification document such as an identity card, a visa, a passport or a driving licence, a lottery ticket, a transport voucher or a ticket for a cultural or sports event.

21. Security document according to any of claims 17 to 20, the substrate comprising compounds extracted from at least two different hardwood species, in particular, on the one hand, eucalyptus and on the other hand, a hardwood selected from the group consisting of birch, bergamot, chestnut, oak, beech, styrax, tupelo, poplar and tulip tree.

Images