MX2011009553A

MX2011009553A - Laser-markable substrate, and associated manufacturing method.

Info

Publication number: MX2011009553A
Application number: MX2011009553A
Authority: MX
Inventors: Sandrine Rancien
Original assignee: Arjowiggins Security
Priority date: 2009-03-13
Filing date: 2010-03-15
Publication date: 2011-10-12
Also published as: EP2406084A1; WO2010103499A1; BRPI1009820A2; FR2943074B1; CA2754867A1; US20120103545A1; RU2011137051A; FR2943074A1

Abstract

The present invention relates to a laser-markable substrate, comprising at least one material capable of forming a colored mark under laser irradiation and at least one tamper-proof agent producing an irreversible visible coloration when an attempt is made to chemically erase the mark.

Description

SUBSTRATE THAT CAN BE MARKED WITH LASER RAY AND PROCEPTION OF ASSOCIATED MANUFACTURING | Field of the Invention The present invention relates to the domain of substrates that can be marked with laser beam, especially security documents, in particular security documents, and relates inter alia to a substrate that provides a colored mark under irradiation with laser beam and to the associated manufacturing process.

In the description, "paper" means any sheet obtained by the wet way with the aid of a suspension of natural cellulose fibers and / or mineral, vegetable or organic fibers other than cellulose, possibly synthetic, which may contain various fillers and various additives commonly used in stationery.

Background of the Invention In order to include the visible marks (or inscriptions) on a substrate, especially the marks such as linear or matrix (2D) bar codes, it is already known to use laser irradiation labeling, for example with the help of lightning infrared laser, especially a laser beam of C02, a laser beam of YAG (Itrium Alumina Garnet) or even a laser beam of: Nd YAG (Neodymium Itrium Alumina Garnet).

REF.223695 j Labeling by irradiation with a laser beam of a standard paper substrate, for example for security printing or writing, leads to the obtaining of a label with a reduced contrast, generally of yellow color or. brown, related to the carbonization of the substrate at the time of marking.

I Also, in order to improve the contrast of the marking by irradiation with a laser beam, it is already known to incorporate in or to apply, on paper or plastic substrates, the materials sensitive to the laser beam such as mineral charges, inorganic pigments. which include conductive pigments and / or pigments with optical effect I changing, such as the pearlescent silicates marketed especially under the name of LAZERFLAIR® (LS range) by the company MERCK.

US application 2006/0090868 describes a fibrous substrate that can be marked with a laser beam comprising from 1 to 5% of the absorbent materials in the form of inorganic platelets based on pearlescent and conductive pigments.

However, these sensitive materials to the laser beam based on conductive pigments or pigments for this purpose, especially variables optically or interferential, although they improve the contrast of the labeling significantly (increase of the optical density), do not allow to obtain a shaded marking, especially of black color, required for the automatic optical recognition of the marks, for example such as ?? e? barcodes.

In order to provide substrates which, under irradiation of the laser beam, provide black markings, the coating compositions carrying materials sensitive to the marking with a laser beam of a different nature have been developed by different companies .: For example, the compositions marketed under the trademark are already known. PACKMARK * by the company DATALASE, PERGAMARK ^ by the company CIBA or even CODESTRAM * by the company FÜJIHU T. These compositions are coated locally on a substrate, especially a paper, and make it possible to obtain a gray or black marking on the coated substrate after irradiation with laser beam of the coated area ^. These compositions comprise, for example, a binder and an oxyanion of a multi-valent metal, as proposed in the application O 02/074548. These compositions can also be based on carbohydrates.

However, these compositions are expensive to be used, especially because they must be applied locally to the substrate to be marked by an off-line process such as printing. In addition, these compositions are not and can not be adapted for use in the line, especially in the moment of papermaking, for example; for the following reasons: the formulation presents chemical incompatibilities with the binders usually used for the manufacture and transformation of the paper, especially for the preparation of the surface of the paper, by ectftplo by the procedures of press glue or in a press forming a film, its resistance to high temperatures, for example such as the temperatures used at the time of manufacture of the plastic substrates or for the drying devices commonly used in the stationery domain, is reduced (this is the case for example for compositions sensitive to labeling with a laser beam based on carbohydrates such as sucrose or sucrose, or based on encapsulated leuco dyes), they modify the properties; of the surface of the paper, especially its printing capacity, for example by rotocalcography; This is the case of compositions comprising a source, proportion of charges.

The application DE 102 32 786 describes a material that can be marked with laser beam that allows to obtain an enhanced marking that provides a tactile effect.

One of the main advantages of the labeling with Laser beam exposed in prior art documents is its resistance to counterfeiting, both mechanical and chemical. The applications O 99/16625, O 98/48398, EP 0 308 904 and FR 2 496 936 propose especially infalsifiable substrates comprising materials capable of marking by a laser beam. In particular, because of! Links created at the time of irradiation (of the marking) between the material that can be marked with laser beam and the substrate and the fixing of the material that can be marked with lightning i laser on the substrate, the labels created on the substrates are presented as infalsificabies, especially indelibly, mechanically or chemically.

The Applicant, however, has observed! that it is possible to chemically erase labels obtained by irradiation with laser beam on substrates comprising materials sensitive to laser beam, or locally coated with compositions sensitive to laser marking, in particular such as those described above, especially with the aid of certain chemicals or solvents such as oxidants or strong bases for example. Thus, substrates comprising these laser-sensitive materials or coated with these compositions sensitive to the laser beam, and marked by laser beam irradiation, do not offer the properties necessary to prevent the attempts of chemical falsification of the marking with laser beam made on these substrates. These properties are therefore indispensable for any security application and especially for the domain of security documents.

In particular, it is relatively easy to erase a labeling by irradiation with laser beam with chemicals such as sodium hypochlorite (bleach) or sodium hydroxide (soda), among others.

Brief Description of the Invention i Accordingly, there is a need to remedy at least some of the drawbacks mentioned above.

There is a particular need to propose a substrate that can be marked with a laser beam, that is to say it provides a colored marking under irradiation with a laser beam, and that has an optimized composition to allow an incorporation in line, in particular on the machine to make paper, of the materials sensitive to the laser beam.

There is still a need to obtain a substrate that can be marked with laser beam, which has printing properties, especially by rotocalcography, substantially analogous to those of a traditional paper substrate.; As a consequence of the observation of the Applicant described above and in spite of prior art teaching, there is also a need for obtain a substrate that can be marked with laser beam to detect any attempt to falsify, in particular chemistry, due to an attempt to erase the markings made with laser beam.

The object of the invention is to solve these needs totally or partially.

Detailed description of the invention The invention thus has as its object, according to one of its aspects, a substrate that can be marked with a laser beam that carries at least one material capable of forming under a laser beam irradiation a colored mark, and at least one anti-counterfeiting agent, which produces a visible coloration, especially an irreversible visible coloration,! at the time of an attempt to erase the brand, to detect this erasure attempt.

By "irreversible", "permanent" is understood, that is to say, that the coloration can not be erased and that it does not disappear with the passage of time.

The marking and / or coloring can be visible, for example, especially with the naked eye or with the aid of an optical amplification device, under normal illumination (visible light), infrared (IR) and / or ultraviolet (UV) light.

I The marking and / or coloring can form, for example, a stain of the characters, for example, such as ideograms or alpha-numeric signs, a symbol, an image, a logo, a number or a code. I Thanks to the invention, it is possible to know whether the attempt to erase the mark has taken place, thanks to the presence of a colored product obtained by the chemical reaction between at least one chemical counterfeiting agent present in or on the substrate and the products. chemicals used by fraudsters who may try to erase the marks previously made by i irradiation with laser beam on the substrate. The colored product forms a stain on the substrate.

The anti-counterfeiting agent can be incorporated, for example, in or on the substrate at the time of its manufacture.

The same can be incorporated for example: [ mass in the substrate, for example by mixing it with the fibrous suspension in the case of a paper substrate or plastic material intended to be extruded or injected in the case of a plastic substrate, - by impregnation, for example according to a gluing press procedure, - by preparation of the surface, for example by a process of a film-forming press, by coating according to procedures such as coating with a pneumatic blade, Roller coating, flow coating in the form of curtain and lining with bars, or even, - by spray.

The anti-counterfeiting agent can be incorporated into the line or out of line. Preferably, it is incorporated into the line at the time of substrate manufacture.

The anti-counterfeiting agent can be incorporated, for example, over the entire surface of the i substrate or locally, for example according to a continuous band or according to a particular configuration.

The counterfeiting agent can allow for i example the prevention of the chemical erasure of the mark carried out by irradiation with laser beam of the substrate, with at least one of the following compounds: an oxidant, J a strong or weak base, a strong or weak acid, or a polar or apolar solvent. I The anti-counterfeiting agent can make it possible to prevent the chemical erasure of the mark made by irradiating the substrate with laser beam, with oxidants, for example, such as sodium hypochlorite. In this case, the anti-counterfeiting agent can be chosen from the following compounds: manganese, nickel, cobalt or cerium derivatives, and in particular their salts, the pp diamino-diphenyl, its sulphated derivatives or its phosphated derivatives, - vanadium derivatives, 4,4'-diaminodinaphthyl (1,1 '), 1 S, N-orthophenylene isothiourea, primulin,: guanidine derivatives such as diarylguanidine such as diphenylguanidine, or thiazole, benzothiazole or aminonaphthiazole derivatives. i The anti-counterfeiting agent can make it possible to prevent the chemical erasure of the mark made by irradiation with laser beam of the substrate, with bases! strong for example such as soda, and / or weak for example such as sodium carbonate. In this case, the agent against counterfeiting can be chosen from the following compounds: - derivatives of manganese, nickel, cobalt or cerium, and in particular their salts, colored indicators such as paranitrophenol, phenolphthalein, pyranine or a derivative i of xanthene.

The counterfeiting agent can allow preventing the chemical erasure of the mark carried out by irradiating with laser beam the substrate, with strong acids for example such as sulfuric acid, and / or weak for example such as oxalic acid. In this case, the anti-counterfeiting agent can be chosen from the following compounds: a colored indicator, such as a xanthene derivative, - potassium ferrocyanide added with ferric chloride, or a thiazole, benzothiazyl or aminonaphthiazole derivative. : The anti-counterfeiting agent can make it possible to prevent the chemical erasure of the mark made by irradiating the substrate with laser beam, with polar solvents such as ethanol, for example, and / or tolueres such as toluene. In this case, the anti-counterfeiting agent can be chosen from water-insoluble dyes but soluble in oils and solvents. These dyes are used especially for the coloring of petroleum products.

The anti-counterfeiting agent can be compatible with the adhesives used for labels, protective films or visas.

In particular if the substrate is a substrate adhesive, the agent against counterfeiting of the substrate is compatible with the adhesive of the adhesive substrate.

According to another particular case, the agent against i Fake is compatible with the adhesive on a label, a protective film, especially for the data page of a passport, or a visa intended to be in contact with, or applied on, the substrate. Certain adhesives used can in fact react with certain anti-counterfeiting agents. It is in particular i certain anti-counterfeiting agents that make it possible to prevent chemical erasure with an apolar solvent. The person skilled in the art can thus select the counterfeiting agent (s) used so as to avoid an undesirable reaction with the adhesive of a label, with a protective film or with a visa intended to be in the contact with, or applied on, the substrate, and in particular can be moved to avoid certain anti-counterfeiting agents that allow to prevent chemical efficacy with an apolar solvent. : The substrate can carry, for example, a single anti-counterfeiting agent that makes it possible to prevent chemical erasure by several erasure products. It may, for example, carry manganese sulfate, and preferably manganese chloride, to allow the erasure of the mark with the bases to be prevented, for example, such as I the soda but also with the oxidants such as sodium hypochlorite, by the appearance in both cases of a brown spot revealing the erasure attempt. i The substrate can also carry several anti-counterfeiting agents that allow the chemical erasure to be prevented respectively with the various erasure products, especially by the appearance of discoloration of each of the erasure products. It can carry, for example, a thiazole derivative and a derivative of the; xanthene i to allow the prevention respectively of the chemical erasure with oxidants such as sodium hypochlorite by the appearance especially of a orange spot revealing an erasure attempt, but also of the chemical erasure with the bases such as soda, by the appearance especially of a blue spot revealing an attempt of erasure and finally the chemical erasure with acids such as sulfuric acid, by the appearance especially of a stain revealing rose of an erasure attempt.

The invention can allow a user to easily verify any attempt to erase by a chemical the marks made by irradiation with laser beam on the substrate, especially due to the appearance of a color change on the substrate at the place where the product chemical has been applied.; The choice of material capable of forming a colored mark under irradiation with a laser beam may depend i of the contrast you want to obtain and the length | of irradiation wave of the laser beam used. In particular, a material that reacts with the marking by a laser beam that emits a light at a wavelength between 100 nm and 11.5 μ? it can be the commercial product MICABS of the company MERCK. In particular, a material that reacts with infrared laser beam marking, especially C02, which emits a light at a wavelength between 9 and 11.5 μt ?, it may be ® chosen from the following commercial products: MARK IT from ENGELHARD, PACKMARK® from DATALASE, FAST MARK * from POLYONE, CERMARK® from DMC2 or LAZERFLAIR® from MERCK.

The material capable of forming a cblocked mark under irradiation with laser beam can also cause the formation of an enhancement, especially by low expansion or the effect of irradiation with laser beam.

The laser beam that allows to create a brand can be: a laser beam of a gas, especially a neutral atomic laser beam, for example a helium-cadmium laser beam that emits in the range of visible UV at a wavelength of 442 nm, an ionized atomic laser beam or a molecular laser beam , for example a nitrogen laser beam (N2) that emits in the UV range at a wavelength of 337 nm or a laser beam of C02 that emits in a wavelength between 9 and 11.5 μp ?, a laser beam of a solid, for example a i ruby laser beam, glass contaminated with neodymium, alexandrite or YAG eventually impurified with rare earth elements, a laser beam of a liquid (or dyes), for example that emits in the UV range at a wavelength comprised between 100 and 350 nm or for example a laser beam pumped by the YAG X2 laser beam or pumped by the laser beam. laser beam of N2, or I a semi-conductor laser beam, for example an arsenic-gallium laser beam.

Preferably, the material capable of forming a colored mark under irradiation with laser beam will be chosen among the derivatives of mica, or even between the transition metals that induce a change of color by the change of the oxidation state such as molybdates, tungstates and vanadates, and in particular octamolybdates, heptamolybdates and amines molybdates. Such materials are especially described in the international application WO 02/074548.

The material capable of forming a colored mark under irradiation with laser beam can be incorporated for example into or on the substrate at the time; from his manufacturing.

The same can be incorporated for example: in bulk in the substrate, for example by mixing it with the fibrous suspension in the case of a paper substrate or a plastic material intended to be extruded or injected in the case of a plastic substrate, by impregnation, for example according to a gluing press procedure, - by preparation of the surface, for example by a process of a film-forming press, by coating according to the procedures such as coating with a pneumatic knife, roller coating, flow coating in the form of a curtain and coating with bars, or even, - by spray.

The material can be incorporated in the line or outside the line. Preferably, it is incorporated into the line at the time of manufacturing the substratum.

Preferably, the material capable of forming the colored mark will be incorporated into the composition for the preparation of the surface of the substrate, especially the paper.

The material can be incorporated for example over the entire surface of the substrate or locally, for example according to a continuous band or according to a particular configuration. Where appropriate, the web or the particular configuration can be superimposed, in particular, with or covered by, respectively, the web or the particular configuration according to which the agent (against counterfeiting has been incorporated into the substrate).

The material can be capable of marking by a laser beam such as those described above, especially a UV laser beam or an infrared laser beam, in particular a C02 laser beam and / or a YAG laser beam, among others. The material can still be capable j of the marking by a femtosecond laser beam. 1 The material capable of marking by a laser beam and i the anti-counterfeiting agent can be mixed 1 in the same composition, especially an ink, a varnish, a finishing, coating, surface preparation or impregnation composition. The composition can be incorporated according to the processes described above, over the entire surface of the substrate or locally, for example according to a continuous band or according to a particular configuration.

The substrate can still carry paper mineral charges such as, for example, kaolin, talc, titanium dioxide, aluminum silicate, alumina hydrate, calcined kaolin, among others. The charges Papermaking minerals can be introduced in bulk into the substrate to increase the opacity and improve the printability, especially by rotocalcography, of the substrate.

The choice of mineral fillers used in the substrate can also influence the contrast of the marking obtained. | In particular, it is preferable to use an absorbing mineral charge in the infrared to improve the contrast obtained at the time of marking with the laser beam. The Applicant has highlighted the fact that, among the usual mineral fillers, the alumina trihydrate and especially the calcined kaolin make it possible to reinforce the contrast of the marking made, in particular with the C02 laser beam. For example it is possible to use calcined kaolin marketed under the name of A SILEX 93® by the company ENGELHARD. ! The substrate can still carry surface binders. The presence of certain surface binders can also make it possible to improve the contrast.

The surface binders can be chosen, for example, from polyvinyl alcohol (PVA), starch or a latex, alone or mixed. These super-solid binders may or may not be accompanied by insolubilizing agents and surface bonding products to offer a better final printing capacity, especially for rotocalcography, to the substrate.

Preferably, the surface binders can be PVA, especially highly hydrolyzed, for example when much of 94%, because it offers a I high contrast, for example for marking by the C02 laser beam.; The substrate can be a plastic substrate. The substrate can be a paper.

The substrate may be, for example, based on cellulose fibers (in particular cotton fibers) and / or on natural organic fibers other than cellulosics and / or synthetic fibers, for example, such as polyester or polyamide fibers. and / or optionally mineral fibers, for example, such as glass fibers.

The substrate can carry one or several impressions, for example made by rotocalcographic printing, short-cut printing, laser beam, inkjet, heliogravure, screen printing and / or flexography, among others.

The concentration of the material capable of forming a colored mark may be between 0.1 and 10% by dry weight with respect to the weight of the substrate, and preferably between 1 and 10%. i The concentration of the anti-counterfeiting agent that reacts at the time of an erasure attempt I The chemistry of the brand can be included, if applicable, for each agent against counterfeiting used, between 0.01 and 5% by dry weight with respect to the weight of the substrate.

The substrate can carry on each of its faces a quantity of material sensitive to lightning marking I laser comprised between 0.1 and 3 g / m2 in dry weight. : The substrate can have a grammage between 30 and 200 g / m2.; The substrate can carry a classic or safety ink, especially fluorescent, phosphorescent, magnetic, photochromic, thermochromic, piezochromic, among others. i The substrate can carry an authentication and / or identification security element. i Among the security elements, some are visible to the naked eye, with visible light, without the use of a particular device. These security elements carry, for example, a watermark, colored fibers or strips, printed, metallized or holographic threads, holographic metal foils or impressions with a variable optical effect.

These security elements are called first and level.

Other types of security elements are detectable only with the aid of a relatively simple apparatus such as a lamp that emits in the I ultraviolet or infrared range. These security elements carry, for example, fibers, strips, bands, threads or particles. These security elements can be visible to the naked eye or not, being for example luminescent under the illumination of a Wood lamp that emits at a wavelength of 365 nm.

These security elements are called second level.

Other types of security elements need a more sophisticated detection device for detection.

These security elements are capable, for example, of j generate a specific signal when they are subjected, simultaneously or not, to one or more external sources of excitation. The automatic detection of the signal allows authenticating, if necessary, the document.

These security elements have for example tracers present in the form of active material, particles or fibers, capable of generating a specific signal when these tracers are subjected to an excitation - optronic, electric, magnetic or electromagnetic.

These security elements are called third level dje.

The substrate can carry at least one security element of the first, second and / or third levels.

Another object of the invention is the use of a substrate that can be marked by laser beam, as defined above, in a security document and / or a security article.

The security document may for example be a means of payment, such as a banknote, a check, a purchase voucher or a proof of payment of a restaurant, an identity document such as an identity card or an official document. such as a visa, a passport or a driver's license, a proof of payment of the lottery, a transportation certificate, or even a proof of payment for i the entrance to cultural or sports events.

The security article can be chosen for example between a security label, a container, especially a container for medicaments or food, for cosmetics, for perfumes, of electronic parts, of spare parts, a sheet used in the domain medical or hospital, especially a paper used to manufacture sterilization containers, or even an art paper.

The invention also has as its object, according to another of its aspects, a method of manufacturing a substrate that can be marked by laser beam as defined above.

The procedure may comprise the stage that it consists of introducing by impregnation, especially according to a gluing press procedure, or by the preparation of the surface, especially according to a í press procedure for forming a film, at the time of the manufacture of the substrate on a paper machine, the material capable of forming a colored mark under irradiation with subsequent laser beam.

Eg emplos Preliminary observations The substrates described in the following presented examples have been marked with a C02 laser beam having the following characteristics:! a laser beam with a wavelength of 10600 nm, I a beam expander (increase in beam size) x 2, - 125 nm focal length, 127 nm lens, and speed of 3500 mm / s.

The marked papers have been evaluated immediately, in terms of the contrast of the marking with laser beam; by a measurement of the optical density, as well as in terms of the resistance of the marking to the attempts of chemical erasure with acid, soda, sodium hypochlorite, ethanol and toluene.

Formulation 1 (control sample) A substrate that can be marked with laser beam, with the help of a traditional paper making machine and using the following formulation according to the prior art.

Pulp (refined at 35 degrees Schopper-Riegler - ° SR) - Long fibers: 60%, I short fibers: 40%.

Mixer - Mineral load: 15% dry weight of kaolin calcinadá.

Cover box - Holding agent: 1.5% by mass with respect to the paper production of the paper making machine of cationic starch, for example potato-based, ( Sizing agent: 3.5% by mass of the commercial solution with respect to the paper production of the cellophane-based cationic emulsion paper machine.

Sizing press (surface treatment, for 2000 1) - Binder: 200 kg of modified corn starch, - Binder: 20 kg of polyvinyl alcohol (PVA), - Antifoam: 0.35 kg of an aqueous emulsion of an aliphatic mixture of the hydroxy compounds, - Insolubilization agent; 3 kg of a commercial modified glyoxal solution, - Material sensitive to laser marking: 250 kg LAZERFLAIR® 800 marketed by the company MERCK.

The results show that a brown and non-black yellow contrast is obtained at the time of marking with CQ2 laser beam of the paper manufactured according to the formulation 1. It is noted that it is easy to erase the labeling with laser beam with sodium hypochlorite at 12% of chlorine or with a 5% sodium hydroxide solution. i Formulation 2 A substrate that can be marked with a laser beam is manufactured with the help of a traditional papermaking machine with the same formulation as before but replacing LAZERFLAIR® 800 with a monolithoblase.

The results show that this time a grayish black contrast is obtained at the moment of lightning marking I C02 laser of the paper manufactured according to the formulation 2. It is noted that it is easy to erase the labeling with laser beam with sodium hypochlorite at 12% chlorine or with a 5% sodium hydroxide solution.

Formulations 3, 4, 5, 6, 7 and 8 A substrate that can be marked with laser beam is manufactured with the help of a traditional paper making machine and using the following formulation:; Pulp (refined at 35 degrees Schopper-Riegler - ° SR) Long fibers: 60%, - short fibers: 40%. : Mixer - Mineral load: 15% dry weight.

Cover box - Withholding agent: 1.5% in mass with respect to the I paper production of cationic paper starch making machine, for example potato based, Adhesive agent commercial solution with respect to the production of paper machine for making cationic emulsion paper based on i cellophane.

Sizing press (surface treatment, for 2000 u i - Binder: 200 kg of modified corn starch, - Binder: 20 kg of polyvinyl alcohol (PVA), - Antifoam: 0.35 kg of an aqueous emulsion of an aliphatic mixture of the hydroxy compounds, - Insolubilization agent: 3 kg of a commercial modified glyoxal solution, - Material sensitive to laser marking: 250 kg of octamolybdate ammonium.

Tests are carried out with different types of mineral fillers different from the kaolin (used in formulation 2): rutile titanium dioxide (formulation 3), precipitated calcium carbonate (formulation 4), sodium silicoaluminate (formulation 5) , hydroxide aluminum (formulation 6), talc (formulation 7) and calcined kaolin (formulation 8). ] The results of the tests of the marking (measurement of the optical density) by irradiation with laser beam of C02 are the following: The results show that a better contrast of the marking is obtained by irradiation with laser beam due to the use of calcined kaolin, sodium silicoaluminate or aluminum hydroxide as the paper mineral load.

However, it is now easy to erase the laser beam mark with 12% sodium hypochlorite or 5% sodium hydroxide solution. ' Formulations 9, 10, 11 and 12 Four substrates are produced which can be marked by laser beam irradiation on a traditional papermaking machine according to the following common mass formulation (before surface treatment): Pulp (refined at 35 degrees Schopper-Riegler - ° SR) Long fibers: 60%, short fibers: 40%.

Mixer - Mineral load: 15% dry weight of calcined kaolin.

Cover box - Retention agent: 1.5% by mass with respect to the paper production of the cationic paper making machine, for example, potato-based, Sizing agent: 3.5% by mass of the commercial solution with respect to the paper production of the cellophane-based cationic emulsion paper machine.

The following four squeeze press formulations ("size pr ss") are applied immediately in the line on the preceding fibrous blankets respectively: Sizing press (surface treatment, for 2000 1) for formulation 9! - Binder: 200 kg of modified corn starch, - Antifoam: 0.35 kg of an aqueous emulsion of an aliphatic mixture of the hydroxy compounds, - Insolubilization agent: 3 kg of a commercial modified glyoxal solution, - Material sensitive to laser marking: 250 kg of octamolybdate ammonium.

Sizing press (surface treatment, for 2000 1) for formulation 10 - Binder: 200 kg of modified corn starch, - Binder: 20 kg of polyvinyl alcohol (PVA), j - Antifoam: 0.35 kg of an aqueous emulsion of an aliphatic mixture of the hydroxylated compounds, \ - Insolubilization agent: 3 kg of a commercial modified glyoxal solution, - Material sensitive to laser marking: 250 kg of octamolybdate ammonium.

Sizing press (surface treatment, for 2000 1) for formulation 11 í - Binder: 100 kg of polyvinyl alcohol (PVA), - Antifoam: 0.35 kg of an aqueous emulsion of an aliphatic mixture of the hydroxy compounds, - Insolubilization agent: 3 kg of a modified commercial glyoxal solution i, - Material sensitive to laser marking: 250 kg of octamolybdate ammonium. j Sizing press (surface treatment, for 2000 1) for formulation 12 1 - Binder: 100 kg of polyvinyl alcohol (PVA), - Antifoam: 0.35 kg of an aqueous emulsion of uria aliphatic mixture of the hydroxy compounds, - Surface glueing agent: 50 kg of a modified acrylic styrene derivative, - Insolubilization agent: 3 kg of a commercial modified glyoxal solution, - Material sensitive to laser marking: 250 kg of octamolybdate ammonium.

It is observed that the best results in terms of the contrast of the labeling by irradiation with laser beam of C02 are obtained on the paper manufactured according to the formulations 11 and 12 when a surface binder is used in the form of polyvinyl alcohol (PVA).

However, it is easy to erase the mark of the laser beam with 12% chlorine bleach or 5% sodium hydroxide solution.

On the other hand, the paper manufactured according to the formulation 12 presents a better capacity for printing by rotocalcography, laser beam and ink jet than that manufactured according to the formulation 11.

Formulation 13 A paper substrate is manufactured which can be marked by irradiation with laser beam according to the invention on a traditional paper making machine with the following characteristics: Pulp (refined at 35 degrees Schopper-Riegler - ° SR) Long fibers: 60%,. short fibers: 40%.

Mixer - Mineral load: 15% dry weight of calcined kaolin, I - Agent against counterfeiting based on xanthene (colored indicator): 0.3% by mass of the commercial solution with respect to the paper production of the papermaking machine.

Cover box - Retention agent: 1.5% by mass with respect to the paper production of the cationic paper making machine, for example, potato-based, Sizing agent: 3.5% by mass of the commercial solution with respect to the paper production of the cellophane-based cationic emulsion paper machine. ! Sizing press (surface treatment, for 2000 1) - Binder: 100 kg of polyvinyl alcohol (PVA), - Antifoam: 0.35 kg of an aqueous emulsion of an aliphatic mixture of hydroxylated compounds, - Insolubilization agent: 3 kg of a commercial modified glyoxal solution, - Material sensitive to laser marking: 250 kg of ammonium octamolybdate, - Agent against counterfeiting: 20 kg of manganese chloride.

A paper having a high contrast is obtained, especially by labeling by irradiation with a C02 laser beam. In addition, an attempt to erase the brand made of laser beam, for example with the help of sodium hypochlorite at 12 degrees chlorine or 5% sodium hydroxide solution, causes the appearance of a brown colored spot that reveals the attempt to falsify labeling on paper. An attempt to erase the mark made by laser beam with the help of an acid, such as 5% sulfuric acid, causes the appearance of a pink colored spot that also reveals the attempt to falsify the marking on the substrate.

The expression "carrying one" is synonymous with "carrying at least one". j I It is noted that in relation to this date the best method known by the applicant to carry out the aforementioned invention, is that which is clear from the present description of the invention.

Claims

CLAIMS Having described the invention as antecedent, the content of the following claims is claimed as property:

1. A substrate that can be marked by laser beam, characterized in that it comprises at least one material capable of forming a colored mark under irradiation with laser beam, and at least one anti-counterfeiting agent that produces an irreversible visible coloration at the time, of a chemical erasure attempt of the brand.

2. The substrate according to claim 1, characterized in that the anti-counterfeiting agent is incorporated in bulk, by impregnation, by treatment of the surface, by coating 1 or by spraying.

3. The substrate according to any of the preceding claims, characterized in that the anti-counterfeiting agent makes it possible to prevent the chemical erasure of the brand with at least one of the following compounds: an oxidant, a strong or weak base, a strong or weak acid, a polar or apolar solvent. i

4. The substrate in accordance with any of the preceding claims, characterized in that the anti-counterfeiting agent makes it possible to prevent the chemical erasure of the brand with oxidants and is chosen from: manganese, nickel, cobalt or cerium derivatives, and especially their salts, the pp diamino-diphenyl, its sulphated derivatives or its phosphated derivatives, the vanadium derivatives, 4,4'-diaminodinaphthyl (1,1 '), - S, N-orthophenylene isothiourea, [ the primulina, guanidine derivatives such as diarylguanidine, such as diphenylguanidine, or thiazole, benzofciazole or aminonaphthiazole derivatives.

5. The substrate according to any of the preceding claims, characterized in that the anti-counterfeiting agent makes it possible to prevent chemical erasure with strong and / or weak bases and is chosen from: - derivatives of manganese, nickel, cobalt or cerium, and especially their salts, colored indicators such as paranitrophenol, phenolphthalein, pyranine or a xanthene derivative.

6. The substrate in accordance with any of the preceding claims, characterized in that the anti-counterfeiting agent makes it possible to prevent the chemical erasure of the mark against strong and / or weak acids and is chosen from: a colored indicator such as a xanthene derivative, - potassium ferrocyanide added with ferric chloride, or a thiazole, benzothiazole or aminonaphthiazole derivative.

7. The substrate according to any of the preceding claims, characterized in that the anti-counterfeiting agent makes it possible to prevent chemical erasure with polar and / or apolar solvents and is chosen from water-insoluble dyes but soluble in oils and solvents, especially in ethanol and / or tolu no.

8. The substrate according to any of the preceding claims, characterized in that the anti-counterfeiting agent is a manganese derivative, especially a manganese salt and preferably manganese chloride.

9. The substrate according to any of the preceding claims, characterized in that the material capable of forming a colored mark under irradiation with laser beam is incorporated in mass, by impregnation, by surface treatment, by coating; or by spraying.

10. The substrate according to any of the preceding claims, characterized in that the material is capable of marking by a UV laser beam or by an infrared laser beam, in particular a CO2 laser beam and / or a YAG laser beam.;

11. The substrate according to any of the preceding claims, characterized by the I Colored mark presents an enhancement.

12. The substrate in accordance with any of i the preceding claims, characterized in that the material capable of forming a mark is chosen from mica derivatives, molybdates, tungstates and vanadates, and especially octamolybdates, heptamolybdates and amines molybdates. 1

13. The substrate according to any of the preceding claims, characterized in that it carries a mineral charge that is absorbing in the infrared range, especially of the calcined kaolin; or of alumina trihydrate.

14. The substrate according to any of the preceding claims, characterized in that it carries polyvinyl alcohol, especially highly hydrolyzed, especially when very much 94%.

15. The substrate according to any of the preceding claims, characterized in that it is a base of cellulose fibers, especially a paper.

16. The substrate according to any of the preceding claims 1 to 14, characterized in that it is a plastic substrate.

17. The substrate according to any of the preceding claims, characterized; because it comprises at least one authentication and / or identification security element.

18. The substrate according to any of the preceding claims, characterized in that the concentration of the material capable of forming a colored mark is between 0.1 and 10% by dry weight with respect to the weight of the substrate, and preferably between 1 and 10% .

19. The substrate according to any of the preceding claims, characterized in that the concentration of the anti-counterfeiting agent is between 0.01 and 5% by dry weight with respect to the weight of the substrate. ,

20. The use of a substrate that can be marked with laser beam according to any of the preceding claims, in a security document and / or a security article.

21. A manufacturing process of a Í substrate that can be marked with laser beam according to any of claims 1 to 19, characterized in that it comprises the step consisting of introducing in bulk, by impregnation, especially according to a glue press procedure, or by preparing of the surface, especially according to a press procedure for forming a film, at the time of the manufacture of the substrate on a papermaking machine, the material capable of forming a colored mark under irradiation with laser beam.