Polymer particles for marking / coding objects, their manufacturing process and composition based on these particles

Abstract

The invention aims to provide markers for the identification and / or authentication of objects, in particular valuable objects, and more precisely markers which are stable, effective, easily synthesizable, economical, tamper-proof and offer possibilities for multiple and complex coding. The invention relates to particles (P) in particular suitable for the marking, identification and / or authentication of objects, in particular valuable objects:- based on at least one polymer carrying chelating groups,- whose largest dimension is between 0.1 and 1000 µm, preferably between 1 and 500 µm, even more preferably between 1 and 50 µm, and- to which are bound at least one mineral marking element (M) and optionally at least one organic marking element (O); at least a part of this (these) mineral marking element(s) (M) being chelated by the polymer.The invention also relates to a powder, a suspension or a composition comprising these P particles, as well as a method of manufacturing them.

Description

Title of the invention: Polymer particles for marking / coding objects, their manufacturing process and composition based on these particles Technical field

[0001] The present disclosure relates to the field of marking objects, in particular valuable or security documents, for authentication and / or identification purposes. In particular, the invention relates to polymer particles which are particularly useful as markers allowing coding and comprising mineral and / or organic marking elements. Prior art

[0002] Objects that can be marked, or even, to increase security, marked and coded, can be, among others, banknotes, sensitive documents, valuables, authentic objects, industrial products (quality tracing), fluids such as groundwater, fluids used in oil / gas exploration, medicines Stolen banknotes can be spotted and identified using smudge inks.

[0003] The marking / coding means used are for example: - particles carrying minerals, such as lanthanides; - mixed organometallic particles composed of polymers and metal salts; - and / or organic markers, for example dyes, pigments, fluorophores, antigens, DNA markers incorporating unique synthetic DNA codes.

[0004] These markers are associated with their own recognition / detection systems. These may be, for example: * visual recognition or by optical microscopy, electron microscopy, in particular scanning electron microscopy (SEM); * analysis by spectrometry, chromatography, by Energy Dispersive X-rays (EDX); * analysis by inductively coupled plasma mass spectrometry, or "Inductively Coupled Plasma Mass Spectrometry" (ICP-MS); * luminescence, such as photoluminescence (fluorescence or phosphorescence) or radioluminescence, etc.

[0005] These markers are expected to be stable, in other words to keep their properties to be detectable over time. In addition, these markers are expected to be easily detectable, specific, difficult to imitate, difficult to remove, invisible to the naked eye, not alter the visual appearance of the marked product, to be easily and quickly dispersible, not to alter the properties of the marked object and to be compatible with coding techniques.

[0006] Coding is a sophisticated means to improve the identification and authentication of marked objects and / or documents. For the specific coding of small entities, it is important that the marker contains the entire code, forms a stable suspension in a possible formulation solvent, and is easily synthesized at a cost consistent with its use.

[0007] In this context, document FR2953840A1 discloses powders of solid solutions of oxides, hydroxides and / or oxohydroxides of lanthanides. These powders can be mixed with staining inks intended for the authentication of stolen banknotes. They are difficult to identify under an electron microscope (SEM), but exhibit characteristic peaks in energy dispersive spectroscopy (EDX). FR2953840A1 further describes a means of coding these powders, through different varieties and concentrations of lanthanides they contain. However, the particles making up the powders according to FR2953840A1 do not have sufficiently distinctive shapes to be easily and quickly detectable, for example, by SEM. In addition, coding with markers according to FR2953840A1 requires a synthesis per code, which is very restrictive when you have to make 100 or 1000 codes. To overcome this, powder mixtures are made to have a sufficient number of codes. Detection of the different powders in a given mixture is necessary to identify the object marked / coded with this mixture. This constitutes a significant constraint for users. Furthermore, it should be noted that the solution proposed by FR2953840A1 is based on powders with very high concentrations of lanthanides, giving rise to very dense powders, which are difficult to disperse in solution, due to their strong tendency to sediment in solvents. Finally, these high concentrations of rare chemical elements such as lanthanides, hamper the economy of marking / coding powders according to FR2953840.

[0008] Document WO2019 / 211292A1 discloses powders formed from particles having two layers of coordination polymers associated with lanthanides. These powders are detectable by luminescence of the lanthanides in the visible and infrared (IR) range. But this detection can be tricky. Indeed, the thickness of the layers influences the intensity of the different bands of the spectrum, which can make them difficult to discern and identify. Furthermore, the specific composition and structure of the particles restrict the coding possibilities. Furthermore, the particles of the powders according to WO2019 / 211292A1 exhibit low stability under certain dissolution conditions. Moreover, the synthesis of these powders is long and difficult. Finally, it is not possible to use these powders independently because they offer little contrast in SEM or EDX, which makes their detection difficult by these analytical techniques. Objectives of the invention

[0009] The invention aims to satisfy at least one of the following objectives among others.

[0010] The invention aims to provide stable markers, so that they can retain their ability to be detectable over time.

[0011] The invention aims to provide effective markers, i.e. easily and quickly detectable.

[0012] The invention aims to provide easily synthesizable and economical markers.

[0013] The invention aims to provide markers offering multiple coding possibilities. and complex.

[0014] The invention aims to provide markers which are tamper-proof.

[0015] The invention aims to provide marking / coding solutions making it possible to ensure specific recognition of objects marked with different analysis techniques, without reducing the accuracy of authentication.

[0016] The invention aims to provide marking / coding particles as well as a marking / coding method which do not harm the objects to be marked / coded.

[0017] The invention aims to provide a method for obtaining these particles, which is reliable, simple and economical.

[0018] The invention aims to provide a high-performance marking / coding powder, suspension or composition for the authentication and / or identification of objects, in particular valuable objects, based on these particles. Summary of the invention

[0019] These objectives are achieved by the invention which proposes particles P, in particular suitable for marking, identifying and / or authenticating objects, in particular valuable objects: - based on at least one polymer carrying chelating groups, - whose largest dimension is between 0.1 and 1000 pm, preferably between 1 to 500 pm, even more preferably between 1 to 50 pm, and - with which is (are) associated at least one mineral element of marking M and possibly at least one organic element of marking O; at least a portion of this mineral marking element M being chelated by the polymer.

[0020] The invention also relates to:

[0021] a powder comprising particles P according to the invention;

[0022] a suspension in a liquid, of a powder according to the invention;

[0023] a method for manufacturing particles P or a powder according to the invention comprising the following successive steps: a) bringing together a liquid, preferably an aqueous liquid, with at least one polymer carrying chelating groups to form a mixture H; b) formation of a gel from the mixture H obtained in step a), preferably by crosslinking; c) transformation of the gel formed in step b) into powder of particles P by drying then grinding or by atomization of this gel; d) optionally, encapsulation of the particles P in at least one envelope, preferably a silica-based envelope; e) at least one association step of at least one mineral element with M marking and, optionally, of at least one organic element with O marking, with the polymer used in step a) and / or with the particles P obtained in step c); at least a portion of this(these) mineral element(s) M of marking being chelated by the polymer constituting the particles; f) and, optionally, at least one step of incorporation of secondary marking mineral elements M2 are in the form of nanoparticles NP.

[0024] The use of these particles or this powder for marking / coding, identification and / or authentication of objects, in particular valuable objects. Brief description of the drawings Fig.l

[0025] [Fig.l] shows an SEM image of the particles according to Example 2. Fig. 2A

[0026] [Fig.2A] shows an SEM image of the particles according to Example 5. Fig. 2B

[0027] [Fig.2B] shows an SEM image of the particles according to Example 5. Fig. 3A

[0028] [Fig.3A] shows an SEM image of the particles according to Example 6. Fig. 3B

[0029] [Fig.3B] shows the elemental composition, obtained by EDX analysis, of the particles of Example 6. Fig. 4A

[0030] [Fig.4A] shows an SEM image of the particles according to Example 7. Fig. 4B

[0031] [Fig.4B] shows an SEM image of the particles according to example 7, on which analysis points 1 to 6 appear in EDX: confer [Fig.4C] & 4D. Fig. 4C

[0032] [Fig.4C] shows the EDX spectrum of the particles according to Example 7. Fig. 4D

[0033] [Fig.4D] shows7 the elemental composition, obtained by EDX analysis, of the particles of example 7. Fig. 5A

[0034] [Fig.5A] shows an SEM image of particles according to Example 8. Fig. 5B

[0035] [Fig.5B] shows the EDX spectrum of banknotes marked with ink comprising particles according to Example 8. Fig. 6

[0036] [Fig.6] represents the spectra obtained in ICP-MS analysis, for smearing inks according to example 9. Fig. 7A

[0037] [Fig.7A] represents the spectra obtained in ICP-MS analysis for smearing inks according to example 10. Fig. 7B

[0038] [Fig.7B] represents the spectra obtained in ICP-MS analysis for smearing inks according to example 10. Definitions

[0039] These definitions are given, as examples, for the interpretation of this document.

[0040] All % and ppm are by mass unless otherwise stated.

[0041] The "largest dimension" of the particles P is determined as follows: measurement eg by observation in optical microscopy or in SEM (for example a SEM ZEISS MERLIN COMPACT VP EDS Oxford Aztec-DDI detector 50 mm2), on one or more observation zones, of a sample of particles corresponding to a po pulation, preferably of at least 100 particles, for example of 100 to 300 particles, eg of 200 particles, (see [Fig.4A]).

[0042] By "chitosan" is meant a natural polymer of the co-polysaccharide type, consisting of a random distribution (statistical co-polysaccharide) or not (block or sequence copolysaccharides) of D-glucosamine (GlcN) and N-acetyl-D-glucosamine (GlcNAc), or even exclusively of D-glucosamine, linked by glycosidic bonds of the [3(1->4] type. Chitosan is not very present in the native state in biomass, it is mainly obtained by chemical modification of chitin, of which it is a derivative. Chitin has a structural role, it is mainly found in certain fungi of which it constitutes the cell wall (Basidiomycetes e.g.: Agariscus campestris, Agariscus bisporus, Ascomycetes, Zygomycetes, and Deuteromycetes), but it also forms the exoskeleton of arthropods (crustaceans, insects) notably in shrimp or crab and the endoskeleton of cephalopods such as squid or cuttlefish.The transition from chitin to chitosan is done by deacetylation, that is to say by alkaline hydrolysis of the acetyl groups to generate primary amine groups. Chitosan is a biodegradable and .

[0043] By "conchoidal fracture" we mean a fracture in a concave or convex curve reminiscent of a shell, or a fracture with the formation of more or less marked curved fracture planes, evoking the growth striations present on the shells of seashells.

[0044] By "torus" is meant the solid generated by the rotation of a circle C of radius r around a straight line D located in its plane at a distance R from its center. The shape of the torus depends on the following relationships: - if 0 <r<R, le tore est dit « ouvert » et ressemble à une chambre à air ou encore à un beignet ("doughnut"'). - if 0 <r=R, le tore est dit « à collier nul » ou tore fermé ou tore jointif ; - if 0 <R<r, le tore est dit « croisé » et ressemble visuellement à une citrouille ; le solide est topologiquement une boule fermée de l'espace tridimensionnel, et sa surface une sphère. - if R=0 <r, le tore est une boule (solide obtenu par la rotation d'un disque autour de l'un de ses diamètres) de rayon r.

[0045] By "retracted sphere" is meant a solid, other than a crossed torus or a zero-collar torus, having the shape of a sphere comprising, on its surface, at least one cavity whose shape is, preferably, polyhedral or curvilinear.

[0046] The mass-average molar masses Mw, in particular of chitosan and its derivatives, are determined by size exclusion chromatography, the experimental conditions of which are described in the publication “Physico-chemical studies of the gelation of chitosan in a hydroalcoholic medium” A. MONTEMBAULT, C. VITON, A. DOMARD, Biomaterials, 26(8), 933-943, 2005.

[0047] The degree of acetylation (DA) of chitosan and chitosan derivative is determined using the proton NMR technique, following the methodology of Hirai (A. HIRAI, H ODANI, A. NAKAJIMA, Polymer Bulletin, 26 (1), 87-94, 1991).

[0048] The degree of crystallinity represents the proportion of matter in the crystalline state. It is determined by X-ray diffraction (Alexander, LE, 'X-ray Diffraction Methods in Polymer Science', Wiley-Interscience, New York, 1969, p. 137).

[0049] The size of crystallites, particularly of chitosan and its derivatives, can be determined by studying the width of the diffraction peaks obtained by the powder method, using the Laue-Scherrer relationship (Alexander, LE, 'X-ray Diffraction Methods in Polymer Science', Wiley-Interscience, New York, 1969, p. 137). Detailed description of the invention

[0050] Particles P

[0051] The particles P are, in particular, suitable for marking / coding, to identify and / or authenticate various objects, in particular valuable objects: - based on at least one polymer carrying chelating groups, - the largest dimension of which is between 0.1 and 1000 pm, preferably between 1 and 500 pm, even more preferably between 1 and 50 pm, and - with which is(are) associated at least one mineral element of marking M and possibly at least one organic element of marking O; at least a portion of this(these) mineral element(s) M of marking being chelated by the polymer. By "association" we mean in particular a chemical bond, such as chelation, a physicochemical bond, a physical bond such as inclusion in the same matrix, which may be the particle P, or in the same physical assembly (body) which may be a solid, for example a powder, a liquid, for example a suspension, a gel or any other state.

[0052] Polymers)

[0053] According to one embodiment, the particles P of the invention can be characterized by a concentration of polymer(s), in % by mass relative to the total dry mass of particles and in an increasing order of preference, between 15 and 80; 15 and 70; 20 and 70 or 25 and 60.

[0054] According to one embodiment, the particles P of the invention can be characterized in that the polymer is chosen from polysaccharides, and, preferably, comprises at least one chitosan and / or at least one of its derivatives, and more preferably still, at least one chitosan of formula I and / or at least one chitosan of formula II.

[0055] Chitosan

[0056] According to one embodiment, the chitosan and / or at least one of its derivatives, capable of constituting the polymer(s) of the particles of the invention, may be a statistical polysaccharide with an average molecular mass of between 100kDa and 1000kDa of formula I (or chitosan of formula I): Formula I in which: each Rc independently represents a chelating group, each Z independently represents a linker which may be a single bond or a hydrocarbon chain comprising between 1 and 12 carbon atoms, said chain being able to be linear or branched and being able to comprise one or more unsaturations and being able to comprise one or more heteroatoms, preferably chosen from nitrogen, oxygen, sulfur and atoms of the halogen family, x being able to be between 0.005 and 0.7, preferably between 0.05 and 0.7, and preferentially between 0.2 and 0.6, y can be between 0.01 and 0.7, preferably between 0.05 and 0.2, the ratio y / x being greater than or equal to 0.05, preferably greater than or equal to 0.15, and the sum x + y being greater than or equal to 0.30, preferably greater than or equal to 0.35. In the polysaccharide of formula I according to one embodiment of the invention, x is between 0.005 and 0.6, y is between 0.1 and 0.9, the y / x ratio being greater than 0.16, and the sum x + y being greater than 0.4.

[0057] It is understood that, in formula I above, several Rc groups may be present in the polysaccharide. These Rc groups may be identical or different from each other. They are all independently chosen from the chelating groups. The same applies to the Z binders: several Z binders may be present, and they may be identical or different from each other.

[0058] According to one embodiment of the invention, the chitosan derivative may be a poly- saccharide of formula II (or chitosan of formula II): in which: Rcl and Rc2 are different, and are groups comprising a chelating agent, ZI and Z2, identical or different, are binders which may be a single bond or a hydrocarbon chain comprising between 1 and 12 carbon atoms, said chain being able to be linear or branched and being able to comprise one or more unsaturations and being able to comprise one or more heteroatoms, preferably chosen from nitrogen, oxygen, sulfur and atoms of the halogen family, x is between 0.005 and 0.7, preferably between 0.05 and 0.7, preferentially between 0.2 and 0.6, and more preferentially between 0.25 and 0.4, y is between 0.01 and 0.7, preferably between 0.05 and 0.2, the ratio y / x being greater than or equal to 0.05, preferably greater than or equal to 0.15, the sum x + y being greater than or equal to 0.30, preferably greater than or equal to 0.35, and z is between 0.5 and 1.

[0059] In this specific embodiment, the polysaccharide of formula II may comprise: - a single type of chelating group, Rcl, when z = 1, or - 2 types of chelating groups, Rcl and Rc2, when 0.5 < z < 1.

[0060] According to one embodiment, z is between 0.8 and 0.99, the Rcl group is therefore largely in the majority.

[0061] According to another embodiment, in formula II, x is between 0.005 and 0.6, y is between 0.1 and 0.9, the ratio y / x being greater than 0.16, the sum x + y being greater than 0.4, and z is between 0.5 and 1.

[0062] Preferably, the polymer(s) [eg polysaccharide(s)] of the particles P according to the invention has a complexation constant of at least 1015 for a transition element d or f, preferably between 1018 and 1022.

[0063] The particles P consisting of chitosan of formula I or II, can have a crystallinity rate of between 10 and 25%. The crystallites of the chitosan act as crosslinking nodes allowing a gel to be formed. The largest dimension of the chitosan crystallites of formula I or II may, for example, be between 1 and 20 nm.

[0064] The average molecular mass Mw of the chitosan of the particles P is, for example, between 100 kg / mol and 1000 kg / mol, preferably between 200 kg / mol and 700 kg / mol.

[0065] The degree of acetylation (DA) of the chitosan of the particles P is advantageously less than 40%, preferably less than 10%, for example between 0% and 10%.

[0066] Chelating groups

[0067] In one embodiment of the invention, the chelating groups of the polymer(s) of the particles P, in particular of the polysaccharide(s), and more particularly still of chitosan and / or its derivatives, may be chosen from the groups derived from: - phosphates such as imidodiphosphate, methylenediphosphonic acid, iminodi(methylphosphonic) acid - sulfates such as paratoluenesulfonic acid, 2-aminoethanesulfonic acid - the following compounds: DOTA (acid l,4,7,10-tetraazacyclododecane-N,N',N”,N'”-teracetic acid), NOTA (l,4,7-triazacyclononane-l,4,7-triacetic acid), NODAGA (l,4,7-triazacyclononane-l,4,7-triacetic acid), l,4,7-triazacyclononane-l-glutaric-4,7-diacetic acid), DOTAGA (2-(4,7,10-tris(carboxymethyl)-l,4,7,10-tetraazacyclododecan-l-yl)pentanedioic acid), DOTAM (1,4,7,10-tetrakis(carbamoylethyl)-1,4,7,10 tetraazacyclododecane), NOTAM (1,4,7-tetrakis(carbamoylmethyl)-1,4,7-triazacyclononane), DOTP (1,4,7,10-tetraazacyclododecane 1,4,7,10-tetrakis(methylene phosphonate), NOTP (l,4,7-tetrakis(methylene phosphonate)-l,4,7-triazacyclononane), TETA (acid 1,4,8,1 l-tetraazacyclotetradecane-N,N' ,N' ',N' ”-teraacetic acid), TETAM (1,4,8,11 -tetraazacyclotetradecane-N,N' ,N” ,N” '-tetrakis(carbamoyl methyl), DTPA (diethylenetriaminopentaacetic acid) and DFO (deferoxamine), and combinations thereof, - pyridines, pyrazoles or combinations of these groups such as Me2-CA-BTP (2,6-bis(5,6,7,8-tetrahydro-5,8,9,9-tetramethyl-5,8-methano-l,2,4-benzotriazin-3-yl)pyridine) - quinones, quinolines, quinolones or combinations of these groups such as norfloxacin (acid l-ethyl-6-fluoro-l,4-dihydro-4-oxo-7-(piperazin-l-yl)quinoline-3-carboxylic acid), ofloxacin (acid (±)-9-fluoro-2,3-dihydro-3-methyl-10-(4-methyl-l-piperazinyl)-7-oxo-7H-pyrido [l,2,3-de]-l, 4-benzoxazine-6-carboxylic acid), ciprofloxacin (acid 1-cyclopropyl-6-fluoro-4-oxo-7-piperazin-1-yl-quinoline-3-carboxylic acid) - and combinations of these groupings.

[0068] For the purposes of the invention, the term “group of type Rc” means the Rc groups in the polysaccharide of formula I, and the Rcl and Rc2 groups, when the Rc2 group is present, in the polysaccharide of formula II.

[0069] According to the invention, the Rc, Rcl and Rc2 groups are chelating. In other words, the Rc, Rcl and Rc2 groups make it possible to chelate one or more metals by forming a complex.

[0070] Each of the Rc, Rcl and Rc2 groups may contain one or more coordination sites. Preferably, the coordination site is a nitrogen or oxygen atom. Advantageously, each of the Rc, Rcl and Rc2 groups comprises between 4 and 8 coordination sites, more advantageously between 6 and 8 coordination sites and even more advantageously each of the Rc, Rcl and Rc2 groups comprises 8 coordination sites.

[0071] The term "coordination site" means a single function capable of chelating a metal. For example, an amine function represents a coordination site by the formation of a dative bond between the nitrogen atom and the metal and a hydroxamic acid function also represents a coordination site by the formation of a dative bond between the oxygen of the carbonyl unit and by a covalent bond with the oxygen of the N-oxide unit, the coordination site thus forming a five-membered ring.

[0072] In one embodiment of the invention, for the polysaccharide of formula II, Rcl and Rc2 are independently chosen from the groups derived from: - phosphates such as imidodiphosphate, methylenediphosphonic acid, iminodi(methylphosphonic) acid - sulfates such as paratoluenesulfonic acid, 2-aminoethanesulfonic acid - the following compounds: DOTA (acid l,4,7,10-tetraazacyclododecane-N,N',N”,N'”-teracetic acid), NOTA (l,4,7-triazacyclononan-l,4,7-triacetic acid), NODAGA (l,4,7-triazacyclononane-l-glutaric acid-4,7-diacetic acid), DOTAGA (l,4,7-triazacyclononane-l-glutaric acid-4,7-diacetic acid), 2-(4,7,10-tris(carboxymethyl)-l,4,7,10-tetraazacyclododecan-l-yl)pentanedioic), DOTAM (1,4,7, lO-tetrakis(carbamoylmethyl)-1,4,7,10 tetraazacyclododecane), NOTAM ( 1,4,7-tetrakis(carbamoylmethyl)-1,4,7-triazacyclononane), DOTP (1,4,7,10-tetraazacyclododecane 1,4,7,10-tetrakis(methylene phosphonate), NOTP (l,4,7-tetrakis(methylene phosphonate)-l,4,7-triazacyclononane), TETA (1,4,8,1 l-tetraazacyclotetradecane-N,N' ,N' ',N' ”-teraacetic acid), TETAM (1,4,8,11 -tetraazacyclotetradecane-N,N' ,N” ,N” '-tetrakis(carbamoyl methyl), DTPA (diethylene triaminopentaacetic acid) and DFO (deferoxamine), and combinations thereof, - pyridines, pyrazoles or combinations of these groups such as Me2-CA-BTP (2,6-bis(5,6,7,8-tetrahydro-5,8,9,9-tetramethyl-5,8-methano-l,2,4-benzotriazin-3-yl)pyridine) - quinones, quinolines, quinolones or combinations of these groups such as norfloxacin (acid l-ethyl-6-fluoro-l,4-dihydro-4-oxo-7-(piperazin-l-yl)quinoline-3-carboxylic acid), ofloxacin (acid (±)-9-fluoro-2,3-dihydro-3-methyl-10-(4-methyl-l-piperazinyl)-7-oxo-7H-pyrido [l,2,3-de]-l, 4-benzoxazine-6-carboxylic acid), ciprofloxacin (1-cyclopropyl-6-fluoro-4-oxo-7-piperazin-1-yl-quinoline-3-carboxylic acid) - and combinations of these groups. Preferably for the polysaccharide of formula II, Rcl and Rc2 are independently selected from DOTAGA, DFO, DOT AM and DTPA.

[0073] According to one embodiment, for the polysaccharide of formula II, the Rcl group is DOTAGA, and preferably, Z=1.

[0074] According to one embodiment, for the polysaccharide of formula II, the Rcl group is DOTAGA and the Rc2 group is DFO.

[0075] Spacers or binders, in particular of type Z fZ. ZI and Z2)

[0076] Spacers or binders, in particular of type Z (Z, ZI and Z2) connecting the groups chelating agents to the main chain, in particular in chitosans of formula (I) or (II), are described in more detail below.

[0077] By Z-type binder is meant the Z binders in the polysaccharide of formula I, and the ZI and Z2 binders, when the Z2 binder is present, in the polysaccharide of formula II.

[0078] The choice of binders Z, ZI and Z2 in formulas I and II depends essentially on the groups Rc, Rcl and Rc2 and the metal to be chelated. Indeed, for steric reasons in particular, the groups Rc, Rcl and Rc2 can be more or less close to the 6-membered ring of the nitrogen of the glucosamine unit.

[0079] Preferably, in formula I, each Z is independently a single bond or a hydrocarbon chain comprising between 1 and 12 carbon atoms, said chain possibly being linear or branched and possibly comprising one or more unsaturations and possibly comprising one or more heteroatoms, preferably chosen from nitrogen, oxygen, sulfur and atoms of the halogen family.

[0080] According to one embodiment, in formula I, each Z is independently selected from the group consisting of: a bond, a linear or branched alkyl chain comprising between 1 and 12 carbon atoms, and a linear or branched alkenyl chain comprising between 2 and 12 carbon atoms, said alkyl and alkenyl chains may be interrupted by one or more C6-C10 aryl groups, and / or by one or more heteroatoms or se groups selected from the group consisting of -O-, -S-, -C(O)-, -NR'-, -C(O)NR'-, -NR'-C(O)-, -NR'-C(O)-NR'-, -NR'-C(O)-O-, -OC(O)NR', ​​-C(S)NR'-, -NR'-C(S)-, -NR'-C(S)-NR' said alkyl and alkenyl chains may be substituted by one or more groups selected from the group consisting of halogens, -OR', -COOR', -SR', -NR'2, each R' is independently H or a C1-C6 alkyl.

[0081] Advantageously, in formula I, each Z is independently selected from the group consisting of: a bond and a linear or branched alkyl chain comprising between 1 and 12 carbon atoms, said alkyl chain being able to be interrupted by one or more C6-C10 aryl groups, and / or by one or more heteroatoms or groups selected from the group consisting of -O-, -S-, -C(O)-, -NR'-, -C(O)NR'-, -NR'-C(O)-, -C(S)NR'-, -NR'-C(S)-, -NR'-C(S)-NR', each R' is independently H or C1-C6 alkyl.

[0082] In a particular embodiment, each Z is an alkyl chain comprising between 1 and 12 carbon atoms.

[0083] In another particular embodiment, each Z is a polyethylene glycol (PEG).

[0084] Preferably, in formula II, Z1 and Z2 are independently a single bond or a hydrocarbon chain comprising between 1 and 12 carbon atoms, said chain possibly being linear or branched and possibly comprising one or more unsaturations and possibly comprising one or more heteroatoms, preferably chosen from nitrogen, oxygen, sulfur and atoms of the halogen family.

[0085] According to one embodiment, in formula II, Z1 and Z2 are independently selected from the group consisting of: a bond, a linear or branched alkyl chain comprising between 1 and 12 carbon atoms, and a linear or branched alkenyl chain comprising between 2 and 12 carbon atoms, said alkyl and alkenyl chains being able to be interrupted by one or more C6-C10 aryl groups, and / or by one or more heteroatoms or groups selected from the group consisting of -O-, -S-, -C(O)-, -NR'-, -C(O)NR'-, -NR'-C(O)-, -NR'-C(O)-NR'-, -NR'-C(O)-O-, -OC(O)NR', ​​-C(S)NR'-, -NR'-C(S)-, -NR'-C(S)-NR' said alkyl and alkenyl chains may be substituted by one or more groups selected from the group consisting of halogens, -OR', -COOR', -SR', -NR'2, each R' is independently H or C1-C6 alkyl.

[0086] Advantageously, in the formula, ZI and Z2 are independently selected from the group consisting of: a bond and a linear or branched alkyl chain having between 1 and 12 carbon atoms, said alkyl chain being able to be interrupted by one or more C6-C10 aryl groups, and / or by one or more heteroatoms or groups selected from the group consisting of -O-, -S-, -C(O)-, -NR'-, -C(O)NR'-, -NR'-C(O)-, -C(S)NR'-, -NR'-C(S)-, -NR'-C(S)-NR', each R' is independently H or C1-C6 alkyl.

[0087] In a particular embodiment Z1 and / or Z2 is an alkyl chain comprising between 1 and 12 carbon atoms.

[0088] In another particular embodiment, ZI and / or Z2 is a polyethylene glycol (PEG).

[0089] Variants of chitosan [formulas (I) & (II)] which can constitute the polymer(s) of the particles P

[0090] According to one variant, the chitosan derivative is composed of 3 monomeric units, namely an A unit of N-acetylglucosamine type, a B unit of glucosamine type and a C unit of glucosamine type functionalized by a chelating group (of Rc type) linked by a linker (of Z type) to the nitrogen of glucosamine.

[0091] According to one variant, the chitosan derivative may be a random polymer. In other words, the sequence of the different monomeric units A, B and type C is random.

[0092] In formulas I and II, x represents the proportion of units A and x can be between 0.05 and 0.7, preferably, x is between 0.2 and 0.6, more preferably x is between 0.25 and 0.4.

[0093] In formulas I and II, y represents the proportion of C-type units and y can be between 0.01 and 0.7.

[0094] The remainder of the monomeric units of formulas I and II are B units. Thus, in formulas I and II, the proportion of B units is equal to 1-xy.

[0095] According to the invention, in formulas I and II, the ratio y / x may be greater than or equal to 0.05, preferably greater than or equal to 0.15.

[0096] The combination of the particular ratio between the number of A units and the number of C-type units and the sum of the proportion of A units and the proportion of C-type units makes it possible to obtain adequate chelation and solubility to allow the use of the polysaccharide according to the invention in various fields such as anti-counterfeiting marking.

[0097] Advantageously, x is between 0.2 and 0.6, more preferably x is between 0.25 and 0.4.

[0098] Advantageously, y is between 0.01 and 0.7, preferably between 0.05 and 0.2.

[0099] According to the invention, z is between 0.5 and 1. In other words, the C-type units can be exclusively units comprising ZI as binder and Rcl as chelating group.

[0100] The chitosan derivative according to the invention has a weight average molecular mass of between 100 kDa and 1000 kDa, advantageously, the weight average molecular mass of the polysaccharide according to the invention is between 250 kDa and 750 kDa, more advantageously between 400 kDa and 600 kDa and even more advantageously, between 450 kDa and 550 kDa.

[0101] According to one embodiment, the chitosan derivative can be chosen from the following polysaccharides: - polysaccharide of formula II where z = 1, Rcl is DOTAGA and ZI is a bond; - polysaccharide of formula II where z = 1, Rcl is DTPA and ZI is a bond; and - polysaccharide of formula II where 0.5 < z < 1, Rcl is DOTAGA and ZI is a bond, and Rc2 is DFO and Z2 is selected from the group consisting of: a bond and a linear or branched alkyl chain comprising between 1 and 12 carbon atoms, said alkyl chain possibly being interrupted by one or more C6-C10 aryl groups, and / or by one or more heteroatoms or groups selected from the group consisting of -O-, -S-, -C(O)-, -NR'-, -C(O)NR'-, -NR'-C(O)-, -C(S)NR'-, -NR'-C(S)-, -NR'-C(S)-NR', each R' is independently H or C1-C6 alkyl.

[0102] Marking elements

[0103] Mineral marking elements

[0104] Remarkably, at least a portion of the mineral marking elements M are chosen from: - metals, in particular lanthanides and / or poor metals; - metalloids; preferably among metals or metalloids having an atomic number greater than or equal to 39; - and their mixtures.

[0105] Better still, at least a portion of the mineral elements of marking M are selected from the group of lanthanides, more particularly from Lanthanum, Cerium, Praseodymium, Neodymium, Prometheum, Samarium, Europium, Gadolinium, Terbium, Dysprosium, Holmium, Erbium, Thulium, Ytterbium, Lutetium, preferably from Cerium, Dysprosium, Lanthanum, Terbium, Gadolinium, Samarium, Neodymium and Yttrium or mixtures thereof.

[0106] According to a variant, at least a portion of the mineral marking elements M are selected from niobium, molybdenum, indium, tin, hafnium, tantalum, tungsten, bismuth and / or their mixtures.

[0107] Lanthanides are heavy chemical elements that are more easily detected in EDX and which have a strong affinity with chelating groups, more particularly with DOTA groups.

[0108] Bismuth is a non-radioactive element with a high atomic mass which, thanks to its characteristics, allows the contrast of particles in SEM to be increased.

[0109] Advantageously, the use of the mineral marking elements M mentioned above emits very specific signals which make them easily detectable.

[0110] According to one embodiment, the particles can be characterized in that at least a portion of the mineral marking elements M are primary mineral marking elements M1 and at least another portion of the mineral marking elements M are secondary mineral marking elements M2 different from the primary mineral marking elements M1.

[0111] At least a portion of the primary mineral marking elements Ml are preferably chosen from: - metals, in particular lanthanides and / or poor metals; - metalloids; preferably among metals or metalloids having an atomic number greater than or equal to 39; and their mixtures.

[0112] Advantageously, at least a portion of the secondary marking mineral elements M2 are chosen from: - metals, in particular lanthanides and / or poor metals; - metalloids; preferably among metals or metalloids having an atomic number greater than or equal to 21; - oxides, hydroxides, oxohydroxides of these metals or metalloids; - and their mixtures.

[0113] The secondary marking mineral elements (M2) can also be chosen from: - metals, in particular lanthanides and / or poor metals; - metalloids; preferably among metals or metalloids having an atomic number greater than or equal to 21; - oxides, hydroxides, oxohydroxides of these metals or metalloids; - and their mixtures.

[0114] Advantageously, the secondary marking mineral elements M2 are in the form of NP nanoparticles whose largest dimension is less than 0.1 pm and which are associated with the P particles. The NP nanoparticles are included in the P particles.

[0115] In this embodiment where the particles P comprise primary labeling mineral elements M1 and secondary labeling mineral elements M2, the labeling mineral elements which are chelated are at least in part, preferably in whole, primary labeling mineral elements M1. The wide variety of mineral marking elements that can be stably bound to the P particles, in particular the primary mineral marking elements M1, makes it possible to confer a very wide choice of coding possibilities on the P particles of the invention.

[0116] Organic marking elements

[0117] Advantageously, the organic marking element (O) is chosen from organic dyes, organic fluorophores, nucleic acids, and mixtures thereof.

[0118] Nucleic acids may be single-stranded, double-stranded, linear, or cyclic synthetic DNA strands comprising 10 to 200 base pairs.

[0119] Particle size

[0120] According to a preferred embodiment of the invention, in a given population of particles P, the particles P whose largest dimension is between 0.1 and 1000 pm, preferably between 1 and 500 pm, even more preferably between 1 and 50 pm, are characterized by a concentration, expressed in % by number and in an increasing order of preference, greater than or equal to 50; 60; 70; 80; 90.

[0121] Particle shape

[0122] According to one embodiment, the particles P can be characterized in that at least a portion of the particles P have a retracted sphere shape, a torus shape and / or are distinguished in that they have conchoidal breaks, so that they are quickly identifiable during observation by SEM, for example.

[0123] According to one embodiment, at least a portion of the P particles (Pto particles), in % by volume of particles on the total volume of P particles and in an increasing order of preference, namely: at least 20; at least 30; between 50 and 90; between 60 and 80, has the shape of open toroids.

[0124] According to one embodiment, at least a portion of the particles P (particles Psr), in % by volume of particles on the total volume of particles P and in an increasing order of preference, namely: at least 5; at least 10; between 10 and 70; between 10 and 50; between 20 and 40; has a retracted sphere shape.

[0125] According to one embodiment of the invention, at least a portion of the particles P (particles Pcc), in % by volume of particles on the total volume of particles P and in an increasing order of preference, namely: at least 5; at least 10; between 10 and 80; between 10 and 70; between 10 and 60; between 20 and 50; has conchoidal fractures.

[0126] Encapsulation of P particles

[0127] According to one embodiment, at least a portion of the particles P, preferably at least those comprising organic marking elements, are encapsulated in at least one envelope, preferably a silica-based envelope.

[0128] The particles (P) may be encapsulated in at least one envelope, preferably a silica-based envelope.

[0129] This encapsulation protects, in particular, the particles and / or the organic elements of O marking, subject to biotic or abiotic degradation phenomena, in particular, when they are exposed to the ambient atmosphere.

[0130] Powder, suspension and composition comprising particles P

[0131] The invention relates to: * a powder comprising P particles; * a suspension comprising P particles; * a composition comprising this powder, this suspension or this gel.

[0132] According to one embodiment, the suspension has a particle concentration, in % by mass of particles P relative to the total mass of the suspension and in an increasing order of preference, which is at least 0.01; 0.1; 1; and which is between 1 and 30; 2 and 20; 3 and 10.

[0133] The invention further relates to a composition for marking / coding, identifying and / or authenticating, in particular objects, in particular valuable objects, characterized in that it comprises at least one powder, or a suspension according to the invention, the mineral marking elements M, and, optionally, the organic marking elements O of the particles P, preferably forming an identification code for this composition.

[0134] The invention further relates to a composition for marking / coding, identification and / or authentication, in particular of objects, in particular valuable objects, characterized in that it comprises particles, a powder, or a suspension according to the invention; the mineral marking elements (M), and, optionally, the organic marking elements (O) of these particles (P) preferably forming an identification code for this composition.

[0135] Advantageously, the particles P of the invention are stable in dry or wet form. This opens up a wide field of application for them, and an implementation adapted to the constraints of the object to be marked / coded.

[0136] Process for manufacturing particles

[0137] The invention further relates to a method for manufacturing particles P or a powder according to the invention comprising the following successive steps: a) bringing together a liquid, preferably an aqueous liquid, with at least one polymer carrying chelating groups to form a mixture H; b) formation of a gel from the mixture H obtained in step a), preferably by crosslinking; c) transformation of the gel formed in step b) into powder of particles P by drying then grinding or by atomization of this gel; d) optionally, encapsulation of the particles P in at least one envelope, preferably a silica-based envelope; e) at least one association step of at least one mineral element with M marking and, optionally, of at least one organic element with O marking, with the polymer used in step a) and / or with the particles P obtained in step c); at least a portion of this(these) mineral marking element(s) M being chelated by the polymer constituting the particles.

[0138] The invention further relates to a method for manufacturing particles, in particular particles P or a powder according to the invention, characterized: that it includes the following steps: a) bringing together a liquid, preferably an aqueous liquid, with at least one polymer carrying chelating groups to form a mixture (H); b) formation of a gel from the mixture (H) obtained in step a), preferably by crosslinking; c) transformation of the gel formed in step b) into powder particles (P) by drying then grinding or by atomization of this gel; d) optionally, encapsulation of the particles (P) in at least one envelope, preferably a silica-based envelope; e) at least one association step of at least one mineral element with M marking and, optionally, of at least one organic element with O marking, with the polymer used in step a) and / or with the particles P obtained in step c); at least a portion of this(these) mineral marking element(s) M being chelated by the polymer constituting the particles, f) and, optionally, at least one step of incorporation of secondary marking mineral elements M2 are in the form of nanoparticles NP.

[0139] During step b) of crosslinking, crosslinking agents such as chlorohydrin, epichlorohydrin, glutaraldehyde, formaldehyde, glyoxal, benzoquinone, isocyanate, genipin, can be added to the mixture H.

[0140] During step b), the crosslinking can optionally be carried out using ionizing rays in the presence of tetrachloromethane, or by ionic interaction using the use of free anions or cations such as the use of cations of antimony, arsenic, barium, beryllium, cadmium, calcium, chromium, cobalt, copper, tin, iron, magnesium, manganese, mercury, nickel, scandium, strontium, zinc, bromate, borate, carbonate, chlorite, chromate, cyanamide, dichromate, hydrogen phosphate, phosphate, phosphite, silicate, stannate, stannite, sulfate, sulfite, or tartrate.

[0141] Advantageously, the grinding makes it possible to obtain particles having conchoidal fractures.

[0142] Advantageously, atomization makes it possible to obtain particles having the shape of a retracted sphere torus.

[0143] According to one embodiment of the invention, the method of manufacturing the particles of the invention may comprise a step f) of micro-encapsulation of the particles, preferably by a sol-gel method.

[0144] The addition of a determined quantity of at least one mineral element with marking M and possibly at least one organic element with marking O corresponds to the coding of the particles. The code of a population of particles P associated with at least one mineral element with marking M and possibly at least one organic element with marking O, varies according to the type of element and its quantity.

[0145] Particle Visualization Methods

[0146] According to one embodiment, the particles P can be observed by optical microscopy or by electron microscopy and preferably by SEM.

[0147] For visualization by SEM, the particles (if necessary previously dried on a filter or on a frit in the case where they are in wet form), can be spread on a self-adhesive carbon pad.

[0148] P particles, when deposited on a banknote during the staining of the latter in the event of theft, can also be observed by SEM. To do this, a stained area, for example of approximately 1cm2, of the banknote is cut out and then placed on a self-adhesive carbon support before observation.

[0149] Identification and reading of the code

[0150] As explained previously, the mineral marking elements M, and, optionally, the organic marking elements O of the particles P can form an identification code for the suspension, the powder, or the composition comprising these particles P. Depending on the nature of the mineral marking elements M, the code will be qualified as a primary metallic code (PMC) or a secondary metallic code (SMC) for the particles P comprising respectively primary mineral marking elements M1 or secondary mineral marking elements M2.

[0151] According to one embodiment of the invention, the CPMs and the CSMs can be identified by elementary analysis methods such as EDX analysis, XPS spectroscopy, Raman spectroscopy, ICP-MS, ICP-AES, by optical analysis methods, such as fluorescence spectroscopy, phosphorescence spectroscopy, Fourier transform infrared spectroscopy or any other method known to those skilled in the art.

[0152] When the particles P comprise an organic marking element, the code can be identified by fluorescence spectroscopy, phosphorescence spectroscopy, Fourier transform infrared spectroscopy, under UV illumination or any other method known to those skilled in the art.

[0153] When the particles P comprise nucleic acids, more preferably when the particles P comprise DNA, the code can be identified by PCR, qPCR, LAMP, NGS, by sequencing or by any other method known to those skilled in the art.

[0154] Thus, it is possible to use the particles P according to the invention to chemically mark / code objects, fluids, materials, valuable or security documents for authentication and / or identification purposes and then identify them by one of the techniques mentioned above.

[0155] The invention proposes, thanks to the particles P, to provide effective marking elements, i.e. easily and quickly detectable thanks to their particular shape. In addition, the marking elements of the invention make it possible to confer wide coding possibilities thanks to the high number of possible combinations between the marking mineral elements, and possibly organic marking elements O. The method of manufacturing these markers and the mode of association of the marking mineral elements M (in particular by chelation), and possibly organic marking elements O, with the particles P make it possible to provide a stable and easily synthesizable marking system. Examples

[0156] EXAMPLE 1: Manufacture of chitosan gel and random polysaccharide of formula I

[0157] Manufacture of a random polysaccharide of formula I

[0158] The polysaccharide of formula I (chitosan derivative) is obtained from chitosan by acetylation of a portion of the amine functions, then functionalization of at least a portion of the amine functions still present after acetylation according to the following steps: - Step 1: solubilization of a chitosan in an aqueous solution having a pH between 4 and 5; Solubilization in a 10 L reactor of a mixture of: - 60 g of Matexcel commercial chitosan from "Alaska snow crab" with an average molecular weight of 200 kDa and an acetylation rate of 6.5%, -4L of ultra-pure water (resistivity of 18.2mOhm.cm; TOC < 10 ppb; bacteria < 10 CFU / ml), and 45 mL of glacial acetic acid. The mixture is stirred for 16 hours at a pH of 4.5 ± 0.5. - Step 2: partial acetylation of the amine functions of the chitosan solubilized in step 1 (formation of A units) 1.2 L of propane-1,2-diol are added to the solution from step 1. The whole is stirred for 1 h. 14 ml of acetic anhydride are dissolved in 600 ml of propane-1,2-diol and added for 10 min in order to have a homogeneous acetylation along the polymer chain. The reaction medium is kept stirring for 4 h.

[0159] The acetylation rate can be determined by elemental analysis. The non-acetylated unit of the polysaccharide (unit B) has a molar mass of 161.2 g.mol1 (C6 NO4H11) while the acetylated unit (unit A) has a molar mass of 203.2 g.mol1 (C8NO5Hi3). The elemental analysis of the polysaccharide obtained at the end of acetylation step 2 is as follows: C 39.22%; H 7.55% and N 6.77%, which corresponds to a rate of acetylated units (units A) of 40% (x=0.4)

[0160] - Step 3: functionalization of at least part of the amine functions still present at the end of stage 2 (formation of type C units). 2 L of the solution obtained in acetylation step 2 are placed in a stirred reactor. 120 g of DOTAGA anhydride are then added and stirring is maintained for 16 h. At the end of this reaction, the solution is diluted by 10 in ultrapure water and purified by tangential filtration using a 100 kDa membrane. After a first re-concentration step up to 16 L, the solution is filtered by 480 L of 0.1 M acetic acid solution at constant volume (16 L), followed by 320 L of ultrapure water and by another re-concentration step up to 8 L. HPLC-UV makes it possible to verify that the DOTAGA has been eliminated. The peak around 7 min corresponds to the polymer while the peak around 11 min corresponds to the ungrafted DOTAGA. The solution at a polysaccharide concentration of 10 g / L is then filtered through a nylon filter (0.4 pm) before lyophilization.

[0161] Proton NMR makes it possible to determine the level y of functionalization by DOTAGA on the polysaccharide by knowing the level x of acetylation. The ungrafted and unacetylated unit (unit B) consists of 7 protons, covalently bound to carbon atoms, exhibiting a chemical shift between 2.9 and 4.3 ppm. The acetylated unit (unit A) has these same 7 protons as well as 3 protons, covalently bound to a carbon atom, present on the acetyl characterized by a . chemical shift between 2 and 2.2 ppm. Finally, the unit grafted with DOTAGA (unit C) includes 34 protons, covalently bonded to carbon atoms, 32 of which integrate between 2.9 and 4.3 ppm and 2 integrate between 2 and 2.2 ppm. The NMR spectrum allows, thanks to the integrations of the different massifs, to determine the values ​​of y using the following equation:

[0162] [Math.l] Area2^3 _ 7+25 y Area^, 2 3.¥+2y

[0163] The grafted unit rate (C unit) is approximately 0.1.

[0164] Thus, the polysaccharide obtained has a unit A content of approximately 0.4 (x=0.4), a unit B content of approximately 0.5 (lxy=0.5) and a unit C content of approximately 0.1 (y=0.1).

[0165] The rate of grafted units (unit C) can also be determined by fluorescence with europium. Europium indeed exhibits a luminescence mainly centered around 590 (5D0 -> 7Fi) and 615 nm (5D0 -> 7F2). This luminescence is extinguished when the europium ion is coordinated only with water molecules. The principle of the method for determining the rate of grafted units is to add increasing quantities of europium, so that it is chelated, the luminescence then increases, when all the chelation sites are filled, the luminescence reaches a plateau. In practice, the polysaccharide obtained at the end of step 3 was placed in an acetate buffer at pH 5, a europium chloride salt dissolved in the acetate buffer was then added. A dosage curve is then plotted by exciting at 396 nm and recording the emission at 590 nm.This dosage allows us to reach a quantity of chelate of 0.4 pmol per mg of polymer, i.e. a rate of approximately 10% (y=0.1).

[0166] EXAMPLE 2: Obtaining mixed particles of xerogel type of chitosan 80%-chitosan derivative 20%

[0167] As starting reagents, a batch of Matexcel commercial chitosan of "Alaskan snow crab" origin with an average molecular weight of 200kDa and an acetylation rate of 6.5%, and a batch of chitosan derivative prepared according to the manufacturing method detailed in Example 1 with an average molecular mass of 200kDa with an acetylation degree of 6.5% and which is substituted at 15% by DOTAGA chelating groups, suitable for the chelation of rare earths and other similar metals, are used.

[0168] In an IL reactor equipped with mechanical stirring, 40g of chitosan and 10g of chitosan derivative are suspended in 450ml of ultrapure water. 1.28mL of acetic acid are added to the mixture to allow the two polymers to dissolve properly until a homogeneous solution is obtained. The homogeneous solution is then transferred into a 1.5 L aqueous solution comprising sodium hydroxide at a concentration of 3mol / L and left to stand for 30 minutes to form a gel. The gel obtained is recovered and washed by filtration with three times 1 liter of water. After drying for 24 hours at 65°C, approximately 70 grams of dried gel are recovered and then ground three times using a knife mill (PULVERISETTE 14 classic line FRITSCH) equipped successively with a 2mm sieve then a 500 pm sieve and finally an 80 pm sieve.

[0169] Approximately 55 g of fine xerogel particles composed of 80% chitosan and 20% chitosan derivative are obtained.

[0170] [Fig. 1] represents the SEM image (ZEISS MERLIN COMPACT VP EDS Oxford Aztec-DDI detector 50 mm2) of the particles obtained using the present manufacturing method. As illustrated in [Fig.l], the synthesized particles have conchoidal fractures and are characterized by a larger dimension of between 100 and 200 pm.

[0171] EXAMPLE 3: Particle coding by chelation of a combination of lan-thanides

[0172] In a 2 L flask, 50 g of particles obtained in Example 2 are dispersed in 1 L of ultrapure water (resistivity of 18.2 mOhm.cm; TOC < 10 ppb; bacteria < 10 CFU / ml) in order to obtain a suspension. The pH of the particle suspension is balanced by the addition of glacial acetic acid until the pH is between 6.0 and 6.5. The batch of particles is then coded by adding metals chosen from: cerium, dysprosium, lanthanum, terbium, gadolinium, samarium, neodymium, yttrium.

[0173] We work on aliquots of 1 to 5 mL in which we add, for each metal that we want to chelate in the particles, 100pL of an aqueous solution of chloride of the metal corresponding to 100g / L. We heat the solution obtained at 60°C for 4 days. We obtain a batch of particles linked to the metals by chelation.

[0174] Two hundred batches of unique particles are synthesized by this method. Each batch contains one to eight metals from: cerium, dysprosium, lanthanum, terbium, gadolinium, samarium, neodymium, yttrium. Each time, the solution obtained is clear with particles in suspension (concentration between 39 and 49 g / L depending on the number of lanthanides added) and can be used for a marking application.

[0175] EXAMPLE 4: Marking of banknotes with unique particle codes

[0176] Two hundred 15 mL glass bottles were filled with 9 mL of indelible smearing ink, specially designed for marking banknotes. This ink is marketed by Feerica SA (Portugal), Feerica SA (Portugal), and approved in accordance with the French decree of 18 December 2013 setting out the technical conditions necessary for the approval provided for in Articles R. 613-53 to R. 613-56 of the Internal Security Code.

[0177] This ink is specifically intended for marking banknotes. We add then in each ImL bottle of suspension according to Example 3 comprising coded particles, in order to obtain a marked smearing ink. The bottles are closed and sealed.

[0178] EXAMPLE 5: Obtaining mixed particles of xerogel type of 50% chitosan - 50% chitosan derivative by spray-drying

[0179] 400 mL of a solution comprising 8.375 g / L of chitosan derivative prepared in Example 1 and 3.350 g / L of chitosan referred to in Example 2 are mixed. This solution is then atomized by spray drying using a Buchi B-290 Mini spray dryer. The inlet temperature of the spray dryer is set at 200°C. Approximately 1 g of a fine powder (from approximately 10 μm to approximately 50 μm) comprising slightly electrostatic particles of the invention is obtained.

[0180] Figures 2A and 2B represent the SEM images (JEOL JSM-6010LV Plus) of the particles obtained using the method of Example 5. The particles have a specific shape of retracted spheres and / or tori whose largest dimension is between 1 and 50 pm.

[0181] EXAMPLE 6: Obtaining mixed particles chitosan 56% - chitosan derivative 44% doped with Bi nanoparticles

[0182] In a 1 L reactor, 16.377 g of chitosan derivative (example 2) and 21.123 g of chitosan (example 1) are mixed with 337.5 mL of ultrapure water (resistivity of 18.2 mOhm.cm; TOC < 10 ppb; bacteria < 10 CFU / ml). Glacial acetic acid is added until the polymers are completely dissolved. With mechanical stirring, 18.300 g of bismuth oxide nanoparticles, supplied by the company NanoH SHS, dispersed in 340 mL of ultrapure water are added.

[0183] After 48 hours at room temperature, the solution is poured into an aqueous solution comprising 1 mol / L of sodium hydroxide, then left for 30 minutes to allow the formation of a gel. The gel formed is then washed by filtration and washed 3 times with 1 L of ultrapure water. The gel is dried at 60°C for 48 hours. Approximately 60g of dry gel are obtained and then ground three times using a knife mill (PULVERISETTE 14 classic line FRITSCH) equipped successively with a 2mm sieve then a 500 pm sieve and finally an 80 pm sieve. Approximately 41g of fine particles are obtained.

[0184] [Fig.3A] represents an image obtained in SEM (JEOL JSM-6010LV Plus) of the particles obtained using the method of example 6. [Fig.3B] gives the elemental compositions obtained by EDX analysis (EDS Oxford Aztec-DDI detector X MAXN 50 / INCA software) of 6 different particles (6 spectra) included in the observation corresponding to [Fig.3A] and of which 5 are visible in [Fig.3A]. Particles in the form of retracted spheres are obtained, the largest dimension of which is between 100 and 500 pm in diameter, comprising bismuth oxide nanoparticles. The nanoparticles provide an increase in contrast in SEM compa relatively to particles without bismuth nanoparticles. In EDX (EDS Oxford Aztec-DDI detector X MAXN 50 / INCA software) on 6 analysis points, we find a mass content of bismuth of 32 to 58%.

[0185] EXAMPLE 7: Praseodymium marking of mixed particles of 50% chitosan derived from 50% chitosan doped with bismuth nanoparticles

[0186] To 50 ml of the solution described in Example 6, 2 ml of a commercial solution of glyoxal at 40% in water are added. The solution is stirred manually until a solid texture is obtained. Approximately 3.5 grams of dried gel are thus obtained and then dried at 60°C for 48 hours. The product obtained is ground manually in a mortar. A little less than 2 grams of particles are obtained.

[0187] 20 mg of particles are dispersed in 10 ml of an aqueous solution comprising approximately 10g / L of PrCl3. After 4 days of stirring at room temperature, the solution is centrifuged at 3000 rpm for 5 minutes, then the pellet is recovered and washed three times with 10 ml of acetate buffer pH=4.5.

[0188] Figures 4A & 4B represent a SEM image (JEOL JSM-6010LV Plus) of the pellet after centrifugation and washing according to example 7. The image in [Fig.4C] shows the 6 points 1 to 6 of EDX analysis. [Fig.4C] represents the EDX spectra (EDS Oxford Aztec-DDI detector X MAXN 50 / INCA software) produced from the particles observed in Figures 4A & 4B. Colocalization between bismuth and praseodymium is observed at the particle level.

[0189] EXAMPLE 8: MEB-EDX identification of a banknote stained with marked ink

[0190] 30 mg of particles obtained by following the protocol described in Example 5 are dispersed in 10 mL of indelible smearing ink, identical to that used in example 4. Some of the marked ink is poured onto a counterfeit bill.

[0191] Figure 5A represents the image obtained in SEM (JEOL JSM-6010LV Plus) of a stained part of the banknote with ink prepared according to example 8. In the center of this image, there is a cluster of particles having an appearance similar to those of example 5 (as illustrated in Figures 2A and 2B). Figure 5B represents the EDX spectrum (EDS Oxford Aztec-DDI detector X MAXN 50 / INCA software) produced on one of the particles of the staining ink marked according to example 8. The elementary signature of bismuth is found, which advantageously allows for a double identification system: - in SEM by the shape of the particles, then - in EDX by the elements chelated by the particles of the invention.

[0192] EXAMPLE 9: Authentication by ICP-MS of a sample of commercial ink marked by particles containing five yttrium coding elements, lanthanum, dysprosium, samarium and gadolinium

[0193] For ICP-MS analyses, the solutions are prepared from labeled ink obtained by following the experimental protocol described in Example 4. 400pL of labeled ink is mixed with 8 mL of 69% nitric acid and 2 mL of 30% v / v hydrogen peroxide. The sample is digested by an Anton Par microwave using the following protocol: - a temperature gradient from 0° to 200°C for 10 minutes - 20 minutes at a fixed temperature of 200°C.

[0194] Once returned to room temperature, the sample is degassed and 1 ml is taken and diluted in 5 ml of ultrapure water. Then 1 ml of this sample is taken and diluted again in 9 ml of ultrapure water. [Fig. 6] represents the spectra obtained in ICP-MS analysis (Perkin Elmer NexION 2000) by a semi-quantitative method. In this [Fig. 6], spectrum a) represents smear ink not labeled by the particles of the invention comprising lanthanides (europium, holnium, praesodymium, erbium). This smear ink is identical to that used in example 4. This spectrum highlights the presence of europium, praesodymium and holmium at very high levels.

[0195] Spectrum b) of [Fig.6] is obtained in the same way as spectrum a) but for a smearing ink marked by the particles of Example 4. It shows the presence of specific marking elements such as yttrium, lanthanum, dysprosium, samarium and gadolinium at significant levels. In addition, the peaks of these elements have a size proportional to the respective quantities of each of these elements. Thus, the coding of the invention can be identifiable despite the fact that the smearing ink initially comprises lanthanides.

[0196] EXAMPLE 10: ICP-MS authentication of stained banknotes

[0197] Particles obtained according to the method described in Example 3 comprising lanthanum and neodymium were incorporated into a bottle of ink identical to that used in Example 4. 5 ml of this ink were diluted in 1L of a second ink intended for staining banknotes which will be called dilution ink.

[0198] This mixture was applied to a batch of banknotes so that a portion of each banknote was stained (called the stained area) and another portion was not stained (called the unstained area). Five of these banknotes were analyzed. For each banknote, 140 mg of unstained area and 140 mg of stained area were taken. The pieces taken were then cut into small pieces before being dispersed in 10 ml of a 69% aqueous nitric acid solution.

[0199] The samples are then digested in an Anton Paar MultiWave 5000 microwave using the following protocol: - a temperature gradient from 0° to 200°C for 10 minutes; - 20 minutes at a fixed temperature of 200°C.

[0200] Once at room temperature, 1 mL of the digested samples are diluted in 5 mL of ultrapure water and 100 pL of this mixture are diluted in 10 mL of a 1% aqueous nitric acid solution.

[0201] The samples are then analyzed by ICP-MS (Perkin Elmer NexION 2000) using a semi-quantitative method. [Fig.7A] represents the spectra a) and b) obtained by the ICP-MS analysis of the smearing inks associated respectively with the smeared area and the non-smeared area of ​​the banknotes.

[0202] [Fig.7B] represents the spectrum obtained by ICP-MS analysis of a marked area of ​​the banknotes. We find, at high levels, in the staining ink the signals of europium and holmium; in the dilution ink the signals of erbium, barium and cerium; in the analysis of the unstained areas of the banknotes mainly the signal of terbium. We also find at low levels signals which do not correspond to any specific element. Finally, by removing all these signals from the signal of the stained banknote, the isotopic signatures of the elements sought remain: lanthanum and neodymium. We are able to find traces of these elements despite the presence in very large quantities of other markers.

Claims

Claims

1. Particles (P), in particular suitable for marking / coding, identifying and / or authenticating objects, in particular valuable objects: - based on at least one polymer carrying chelating groups, - the largest dimension of which is between 0.1 and 1000 pm, preferably between 1 and 500 pm, even more preferably between 1 and 50 pm, and - with which is (are) associated at least one mineral marking element (M) and possibly at least one organic marking element (O); at least a portion of this (these) mineral marking element(s) (M) being chelated by the polymer.

2. Particles (P) according to claim 1, characterized in that the polymer is chosen from polysaccharides, and preferably comprises at least one chitosan, and more preferably still, at least one chitosan of formula I Formula l in which: each Rc independently represents a chelating group, each Z independently represents a binder which may be a single bond or a hydrocarbon chain comprising between 1 and 12 carbon atoms, said chain being able to be linear or branched and being able to comprise one or more unsaturations and being able to comprise one or more heteroatoms, preferably chosen from nitrogen, oxygen, sulfur and atoms of the halogen family, x being able to be between 0.005 and 0.7, preferably between 0.05 and 0.7, and preferentially between 0.2 and 0.6, y being able to be between 0.01 and 0.7, preferably between 0.05 and 0.2, the ratio y / x being greater than or equal to 0.05, preferably greater than or equal to 0.15, and the sum x + y being greater than or equal to 0.30, preferably greater than or equal to 0.35, and / or at least one chitosan of formula II Rcl and Rc2 are different, and are groups containing a chelating agent, Z1 and Z2, identical or different, are binders which may be a single bond or a hydrocarbon chain comprising between 1 and 12 carbon atoms, said chain being able to be linear or branched and being able to comprise one or more unsaturations and being able to comprise one or more heteroatoms, preferably chosen from nitrogen, oxygen, sulfur and atoms of the halogen family, x is between 0.005 and 0.7, preferably between 0.05 and 0.7, preferentially between 0.2 and 0.6, and more preferentially between 0.25 and 0.4, y is between 0.01 and 0.7, preferably between 0.05 and 0.2, the ratio y / x being greater than or equal to 0.05, preferably greater than or equal to 0.15, the sum x + y being greater than or equal to 0.30, preferably greater than or equal to 0.35, and z is between 0.5 and 1.

3. Particles (P) according to claim 1 or 2, characterized in that at least a portion of the mineral marking elements (M) chosen from: - metals, in particular lanthanides and / or poor metals; - metalloids, - and their mixtures. metals or metalloids having an atomic number greater than or equal to 39.

4. Particles (P) according to claim 3, characterized in that at least a part of the mineral marking elements M are primary mineral marking elements M1 and at least another ... secondary marking M2, different from the primary marking mineral elements Ml

5. Particles (P) according to claim 4, characterized in that the secondary marking mineral elements (M2) are further chosen from: - metals, in particular lanthanides and / or poor metals; - metalloids; preferably from metals or metalloids having an atomic number greater than or equal to 21; - oxides, hydroxides, oxohydroxides of these metals or metalloids; - and mixtures thereof.

6. Particles (P) according to claim 4 or 5, characterized in that the secondary marking mineral elements M2 are in the form of nanoparticles NP whose largest dimension is less than 0.1 pm and which are associated with the particles P.

7. Particles (P) according to any one of the preceding claims, characterized in that the organic marking element(s) (0) is (are) chosen from organic dyes, organic fluorophores, nucleic acids, and mixtures thereof.

8. Particles (P) according to any one of the preceding claims, characterized in that at least a portion of the particles (P) have a retracted sphere shape, a torus shape and / or are distinguished by having conchoidal fractures.

9. Particles (P) according to any one of the preceding claims, characterized in that the particles (P) are encapsulated in at least one envelope, preferably a silica-based envelope.

10. Powder comprising particles (P) according to any one of the preceding claims.

11. A suspension of particles according to any one of claims 1 to 9, or of a powder according to claim 10.

12. Composition for marking / coding, identification and / or authentication, in particular of objects, in particular valuable objects, characterized in that it comprises particles according to any one of claims 1 to 9, a powder according to claim 10, or a suspension according to claim 11; the mineral marking elements (M), and, optionally, the organic marking elements (O) of these particles (P) preferably forming a code identification of this composition.

13. A method of manufacturing a powder according to claim 10, characterized: that it includes the following steps: a) bringing together a liquid, preferably an aqueous liquid, with at least one polymer carrying chelating groups to form a mixture (H); b) formation of a gel from the mixture (H) obtained in step a), preferably by crosslinking; c) transformation of the gel formed in step b) into powder particles (P) by drying then grinding or by atomization of this gel; d) optionally, encapsulation of the particles (P) in at least one envelope, preferably a silica-based envelope; e) at least one step of associating at least one mineral marking element M and, optionally, at least one organic marking element O, with the polymer used in step a) and / or with the powder of particles P obtained in step c); at least a portion of this(these) mineral marking element(s) M being chelated by the polymer constituting the particles, f) and, optionally, at least one step of incorporation of secondary mineral marking elements M2 are in the form of nanoparticles NP.

14. Use of the particles (P) according to any one of claims 1 to 9 or of a powder according to claim 10 obtained by the method according to claim 13, for the marking / coding, identification and / or authentication of objects, in particular valuable objects.

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