WO2008047003A2

WO2008047003A2 - Method for securing valuable documents

Info

Publication number: WO2008047003A2
Application number: PCT/FR2007/001713
Authority: WO
Inventors: Hubert Le Bozec; Régis Reau; Olivier Lohio; Florian Demaimay
Original assignee: Oberthur Technologies
Priority date: 2006-10-17
Filing date: 2007-10-17
Publication date: 2008-04-24
Also published as: EP2084326B1; WO2008047003A3; EP2084326A2; FR2907137A1; ATE513085T1; FR2907137B1

Abstract

The invention relates to a method for securing valuable documents, that comprises the step of exposing said documents to an outer microwave radiation, mainly in case of emergency. The method is characterised in that it comprises a step that involves integrating in each document, during the manufacturing thereof, at least one active substance capable of releasing a gas after the chemical reaction of said active substance triggered by said outer microwave radiation, said gas being released in an amount and at a speed such that the appearance of the valuable documents is degraded. The active substance may for instance include a diazoic, diazonium or azide function. The invention also relates to a valuable document containing at least one such active substance.

Description

SECURING METHOD OF VALUE DOCUMENTS

The present invention relates to a method for securing valuable documents, in particular banknotes, and more particularly to a method for securing valuable documents contained in a security protection or transport enclosure, said method comprising an exposure step said documents to external microwave radiation, especially in case of emergency.

In the field of the protection of valuable documents, in particular banknotes, it is known to use protective enclosures whose access is reserved for key holders only, with material or immaterial support, the container which is also in a controlled and secure environment, for example by means of various shields.

These protective enclosures, however, proved insufficient in the face of aggressions that were skilfully organized and heavily armed. Indeed, the locks installed on said speakers are likely to be forced or defused by said attackers without rendering unusable said valuable documents contained within said speakers.

One solution to this problem was to use secure containers whose opening or attempted opening by an unauthorized person or lacking a suitable opening means, key type or code, triggers a complex mechanism installed within said containers resulting in the destruction, deterioration or indelible marking of valuable documents contained within said containers, rendering unusable or legally identifiable said documents. Various solutions of this type include automatically projecting a dye or destructive product on the documents in case of aggression. These solutions are, however, unsatisfactory in terms of the objectives to be achieved. In particular, the trajectory of the projected products being relatively random, the marking or the deterioration of the valuable documents can prove to be insufficient and not homogeneous on the whole of the document (s). This occurs especially in the case of bank notes bundled together, for which only the edges of the notes are exposed. By cutting the edges of stained or damaged notes, it is therefore possible to safely recover almost all the tickets stored inside the container. To overcome this drawback, a solution proposed by AXYTRANS, particularly in patent EP 188155, consists in triggering a pyrotechnic charge housed in the lid of the secure container, the deflagration of said charge causing both the opening of liquid tanks. marker or destroyer placed inside the container and the partial or total cutting of all valuable documents. Even if this solution leads to a deterioration or a deep marking of the banknotes, the result is still insufficient both in terms of the proportion of notes physically reached by the liquid, as the level of the regularity of said deteriorations or said markings. . In particular, this solution does not control the intensity, shape and positioning of said deteriorations or said markings. This heterogeneity in the physical modification undergone by each of the notes leaves a doubt as to the origin of said modifications and, as a result, does not make it possible to reliably identify a stolen ticket of a non-stolen ticket. In addition, the use of a pyrotechnic charge may present a potential danger to the personnel in charge of the transport of funds, which forces to adopt relatively precise and tedious safety procedures when handling such containers.

Another prior solution, described in patent EP 1 277 881, implements the prior incorporation into valuable documents of an active element capable of converting into heat energy received from an external electromagnetic source, from preferably a microwave radiation. The heat created causes, as the case may be, a melting of said active element, or a local combustion of the document of value at said active element, thus visibly modifying the appearance of the document. The risk in this solution is to lead, in one case, to an uncontrolled combustion of documents and, in fact, the secure container itself, thus exposing those present, on the one hand, to gaseous releases generally toxic and, on the other hand, a serious threat of fire. In the other case, the active element became liquid flows through the pores of the paper in a relatively random path, ultimately resulting in non-homogeneous changes from one document to another. This solution is therefore also unsatisfactory in view of the problem.

One of the aims of the invention is therefore to propose a new method for securing valuable documents that does not have the drawbacks of the abovementioned prior art and, in particular, a method of securing valuable documents that makes it possible to achieve in a simple and fast way, while being without risk for the potential users, with an irreversible physical modification of the valuable documents, rendering said documents unusable or legally identifiable, said modification that can be made in a complete, homogeneous and controlled manner on all the valuable documents.

In this regard and in accordance with the invention, there is provided a method for securing valuable documents, comprising a step of exposing said documents to external microwave radiation, especially in an emergency, remarkable in that it comprises a step of integrating into each document, during its manufacture, at least one active substance able to release a gas following a chemical reaction of said active substance triggered by said external microwave radiation to which it is exposed, said gas being released in a quantity and at such a speed that the appearance of the valuable documents is degraded, this degradation rendering said documents unusable or legally identifiable.

In a particularly advantageous manner, valuable documents are banknotes.

According to a variant of the invention, the gas released is dinitrogen.

For this purpose, the active substance comprises at least one function capable of releasing a molecule of dinitrogen during exposure to the external microwave radiation, said function being chosen from the group comprising the diazo, diazonium and azide functions.

According to a variant of the invention, the active substance is a molecule having at least one diazo function and corresponding to formula (I):

C = N = N R2 (I) in which R ₁ and R ₂ , which are identical or different, represent, independently of one another, a radical alkyl, cycloalkyl, an aromatic ring, a heteroaromatic ring, substituted or not by heteroatomic groups, which may themselves comprise at least one function selected from the group comprising the diazo, diazonium and azide functions. In this case, the chemical modification of the active substance is accompanied by the irreversible release of at least two products of the reaction, namely a first product being an organic group of the carbene type and the second product of the reaction being at least a molecule of dinitrogen, according to the following scheme 1:

Ri R ₁

C = N = N + N≡N

>

R ₂ (D

According to another variant of the invention, the active substance is a molecule having at least one diazonium function and corresponding to formula (II):

R ₃ -N = N _(II) in which R ₃ represents an alkyl, cycloalkyl, an aromatic ring or a heteroaromatic ring, substituted or not by heteroatomic groups, which may themselves comprise at least one function selected from the group comprising diazo, diazonium and azide functions.

In this case, the chemical modification of the active substance is accompanied by the irreversible release of at least two products of the reaction, namely a first product being an organic group of the carbocation type and the second product of the reaction being at least a molecule of dinitrogen, according to the following scheme 2: R - ^ - N = N (R ₃ ) + N≡N

According to another variant of the invention, the active substance is a molecule having at least one azide function and corresponding to formula (III):

R ₄ -N = NN _(ΣII)

wherein R ₄ represents an alkali metal selected from the group consisting of sodium, potassium and lithium, an alkyl, cycloalkyl, an aromatic ring, a heteroaromatic ring, substituted or unsubstituted by heteroatomic groups, which may themselves comprise at least one function selected from the group consisting of diazo, diazonium and azide functions.

In this case, the chemical modification of the active substance is accompanied by the irreversible release of at least two products of the reaction, namely a first product being an organic group of the nitrene type and the second product of the reaction being at least a molecule of dinitrogen, according to the following scheme 3:

R ₄ N = NN- *. R ₄ -N + N≡N

(3)

Advantageously, the active substance has several functions diazo, diazonium and azide, so that the chemical modification of the active substance following exposure to microwave radiation results in the release of several molecules of inert gaseous dinitrogen per active molecule. The heteroatomic groups as defined above may comprise functions chosen from the group comprising the ester, ether, alcohol, amino, thiol, carboxylic acid, nitrile, aldehyde, nitro, and halogen.

The aromatic ring may be a mono or polycyclic aryl radical. The monocyclic aryl radical may be a phenyl radical which may or may not be substituted by one or more alkyl radicals.

For example, for the active substances corresponding to formula (III), it is possible to use as active substance sodium azide, or an active substance corresponding to formula (HIa):

or an active substance having the formula (IHb):

The active substances used in the present invention have the property of being thermally stable, their decomposition temperature being greater than 200 ^° C.

According to the invention, the active substances used, following a chemical reaction caused by exposure to microwave radiation, make it possible to release gaseous dinitrogen in an extremely fast reaction that can be likened to an explosion. The valuable document is then physically degraded irreversibly, this degradation rendering said document unusable or legally identifiable. However, in view of the deposited amounts of said active substance on the valuable documents and the stability of the molecules of formula I, II, III in the absence of microwave radiation, there is no risk for potential users. On the other hand, the gas generated during this chemical reaction is perfectly inert and therefore safe for potential users.

According to another variant of the invention, there is added to the active substance a chemical dopant accelerating the chemical reaction triggered by said external microwave radiation. Preferably, the chemical dopant has good conductive properties. From 1% to 10% by weight of chemical dopant can be used. For example, single-walled carbon nanotubes (SWNTs) may be used. Thanks to the chemical dopant, the deflagration of the active substance under microwave radiation will occur much more quickly. Decreasing the degradation time is an essential point in the quality of the process according to the invention. According to a variant of the invention, the integration of the active substance with valuable documents is carried out by incorporating said active substance into at least one of the constituent elements of said valuable documents. For example, the active substance is incorporated into the carrier of base of the valuable documents, said support being able to be made of paper or plastic, in particular the paper of the banknote.

According to another variant, the active substance is incorporated in a varnish covering said valuable documents, for example an overprint varnish deposited on the valuable documents to be secured. The active substance used in the present invention is colorless or weakly colored and is therefore imperceptible in the latent state.

According to another variant, the active substance is incorporated into an ink printed on said valuable documents, whether the ink is offset, serigraphic, flexographic, typographic, or inkjet, but also of any type of material adapted and applied on the valuable document. In particular, the ink used may be an intaglio type ink, specific to the trustee, which has the characteristic of a large deposit and adjustable (thickness of 20 to 100 microns). Thus, a high concentration of the active substance on a small surface makes it possible, once the microwave radiation is triggered, an identical degradation of all the valuable documents, according to the precise path of the soft-type ink. The present invention also relates to a valuable document capable of being exposed, particularly in case of emergency, to external microwave radiation, comprising at least one active substance as described above, capable of releasing a gas following a chemical reaction of said active substance triggered by said external microwave radiation to which it is exposed, said gas being released in a quantity and at a rate such that the appearance of the valuable document is degraded, this degradation rendering said document unusable or legally identifiable. Advantageously, the valuable document constitutes a bank note.

Therefore, in case of aggression or break-in of a secure container containing said valuable documents incorporating said active substance, it is sufficient to activate an external microwave radiation source inside said container. Said valuable documents are thus exposed to microwave radiation which will cause the chemical reaction to disengage the dinitrogen and cause in particular a visible modification of the general appearance of said valuable documents. The intrusive nature of said microwave radiation, at the heart of the material, allows a homogeneous and complete marking of said valuable documents.

The following examples illustrate the present invention without, however, limiting its scope.

Example 1

Preparation: In a first step, 5.2 g of sodium azide (NaN) are added to a solution of aqueous-based acrylic lacquer (30 ml) having the reference 803 675 W in the PROTECT® range marketed by SICPA. ₃ ) marketed by the company Acros (CAS: 26628-22-8). Tetrahydrofuran (THF) is added and the whole is placed under stirring with the aid of a magnetized bar. The whole is stirred vigorously for two hours at room temperature.

In a second step, the mixture thus obtained is deposited using a pasteur pipette on fiduciary paper formed from cotton fibers, and the size of a conventional banknote. The colorless deposits obtained are dried at room temperature for 24 hours. In a third step, the coated papers are wound on themselves, and placed in the cylindrical cavity of a microwave oven marketed under the brand name Discover® by the Company CEM and described in particular in the patent application WO 02/062104. This microwave oven comprises in particular a source of microwave radiation delivering a focused single-mode beam with a power of 300 W, the beam frequency being between 300 MHz and 30 GHz, and preferably substantially equal to 2.45 GHz. This microwave oven also comprises a waveguide communicating with the source, at least a portion of the waveguide describing a cylindrical arc, and a cylindrical cavity surrounded by the cylindrical portions of the waveguide, several openings being formed. on the walls of the waveguide so as to communicate the waveguide with the cylindrical cavity. The interest of this type of furnace is to concentrate the microwave beams on a well-defined area of the cylindrical cavity, especially where the samples to be tested are positioned. The irradiation time of each coated paper with said active substance is at most 2 minutes, and in this preferred embodiment 15 seconds.

Results: Following the exposure of the varnished paper with said active substance, it is found that wherever the varnish has been deposited, and only in these places, the paper is physically degraded and very distinctly.

By way of comparison, a similar experiment is carried out with the same paper and under the same conditions, the only change being the absence of said active substance. After two minutes of microwave irradiation at 300 W, no similar degradation is obtained. There is therefore a specific effect of the present invention. Example 2

Preparation:

Firstly, triethylene glycol bis-chloroacetate is prepared according to the formula below:

For this purpose, triethylene glycol (5 g, 33.30 mmol) is solubilized in distilled toluene (20 ml).

Chloroacetic acid (6.30 g, 66.61 mmol) is slowly added and the flask is overlaid with Dean-Stark and refluxed for 5 hours. After returning to ambient temperature, the organic phase is washed with a solution of

NaHCO ₃ (3 x 50 mL). The toluene is then evaporated, then the organic phase is taken up in dichloromethane and then dried over MgSO ₄ . The product is isolated as a pale yellow oil (9.71 g, yield = 96%).

¹ H NMR (200 MHz, CDCl ₃ ) δ (ppm): 4.32 (t, J = A.1 Hz, 4H); 4.09 (s, 4H); 3.71 (t, J = 5.1 Hz, 4H); 3.63 (s, 4H).

Triethylene glycol bis-chloroacetate (2.84 g, 9.37 mmol) was then solubilized in DMSO (15 mL) and stirred at room temperature. The sodium azide (1.40 g, 21.55 mmol) is then slowly added and the solution is heated at 40 ° C. for 24 hours. After returning to ambient temperature, the reaction medium is poured into an Erlenmeyer flask containing 150 ml of distilled water cooled with an ice bath. The organic phase is extracted CH ₂ Cl ₂ (3 × 50 μL), then washed with distilled water (3 × 50 mL), and finally evaporated and dried in a vacuum pump to isolate 2.15 g of a pale yellow oil corresponding to the active substance of formula (HIa)

(yield = 73%):

¹ H NMR (SOO MHz, CDCl ₃ ) δ (ppm): 4.31 (t, 4H); 3.88 (s, 4H); 3.69 (t, 4H); 3.61 (s, 4H)

¹³ C NMR (75 MHz) δ (ppm): 168.35 (C); 70.51 (C); 68.78 (C); 64.66 (C); 50.17 (C).

The oil obtained is doped with 1% by weight of single wall carbon nanotubes (SWNTs) supplied by the Chinese company NTP (Shenzen). One drop of the resulting mixture is deposited on paper made from cotton fibers, and the size of a conventional banknote.

Results:

Following the exposure of the paper containing said active substance, it is found that at the place where it was deposited, and only in this place, the paper is physically degraded and very distinctly, and in an extremely low time , of the order of the second. The acceleration of the reaction sought is here obtained significantly.

Example 3 Preparation:

First pentaerythritol tetrafluoroacetate is prepared according to the formula below:

For this, in a 500 ml flask, pentaerythritol (4 g, 29.4 mmol, 1 eq), toluene (100 ml), a catalytic quantity of p-toluenesulphonic acid (1 g) and finally chloroacetic acid (12.49 g, 132 mmol, 4.5 eq). The flask is placed under vigorous stirring, then overfilled with a Dean-Stark fixture and refluxed overnight. After returning to ambient temperature, the toluene is evaporated. The organic phase is taken up in dichloromethane (50 ml), the organic phase is washed with a solution of NaHCO ₃ (3 x 100 ml) and then dried over MgSO ₄ and concentrated in a rotavapor and then in the vacuum of the pump to isolate a product. in the form of a pale yellow oil that crystallizes. The product is washed with pentane (100 ml) and filtered on a frit to obtain a white powder (10.75 g, yield = 83%). ¹ H NMR (SOO MHz, CDCl ₃ ) δ (ppm): 4.31 (s, 8H, Hi); 4.12 (s, 8H, H ₃ ).

¹³ C NMR (75 MHz, CDCl ₃ ) δ (ppm): 166.71 (C ₂ ); 63.30 (C ₃ ); 42.61 (C ₄ ); 40.49 (C ₁ ).

The previously isolated pentaerythritol tetra-chloroacetate (10.75 g, 24.32 mmol) was solubilized in DMSO (30 mL) and stirred at room temperature. Sodium azide (6.80 g, 195 mmol) is then slowly added and the solution is heated at 40 ^° C. for 24 hours. After returning to ambient temperature, the reaction medium is poured into an Erlenmeyer flask containing 150 ml of distilled water cooled with an ice bath. The organic phase is extracted with CH ₂ Cl ₂ (3 × 50 mL), then washed with distilled water (3 × 50 mL), and finally evaporated and dried at vacuum from the pump to isolate 9.2 g of pale yellow oil corresponding to the active substance of formula (HIb) (yield = 81%):

(IIIb)

¹ H-OOO MHz NMR, CDCl ₃ ) δ (ppm): 4.30 (s, 8H, H ₃ ); 3.94 (s, 8H, H _x ). ¹³ C NMR (75 MHz, CDCl ₃ ) δ (ppm): 167.91 (C ₂ ); 62.83 (C ₃ ); 50.20 (C ₁ ); 42.45 (C ₄ ).

IR (KBr): 2108 cm ^-1 (v _{N 3} ) 1735 cm ^-1 (v _ester )

The oil obtained is doped with 10% by mass of single-walled carbon nanotubes (SWNTs), and integrated into an intaglio type ink. The printing process used is of the soft-cut type, known to those skilled in the art. It consists in inking a previously etched plate with a specific ink, with controlled viscosity. The ink is transferred to the paper by pressing on this plate in contact with a paper support.

Results: Following the exposure of the paper support containing the ink and its active substance, it is found that at the place where the ink was deposited, and only in this place, the paper is physically degraded and very distinct, and in an extremely short time, of the order of the second.

Claims

1 - Process for securing valuable documents, comprising a step of exposing said documents to external microwave radiation, especially in an emergency, characterized in that it comprises a step of integrating into each document, when of its manufacture, at least one active substance capable of releasing a gas following a chemical reaction of said active substance triggered by said external microwave radiation to which it is exposed, said gas being released in a quantity and at such a rate that the appearance of valuable documents is degraded, this degradation rendering said documents unusable or legally identifiable.

2 - Process for securing valuable documents according to claim 1, characterized in that the gas released is dinitrogen.

3 - Process for securing valuable documents according to the preceding claim, characterized in that the active substance comprises at least one function capable of releasing a molecule of nitrogen during exposure to external microwave radiation, said function being selected from the group comprising diazo, diazonium and azide functions.

4 - Process for securing valuable documents according to the preceding claim, characterized in that the active substance is a molecule having at least one diazo function and corresponding to formula (I): C = N = N

R _{2 (} i) in which R 1 and R ₂ , which may be identical or different, represent, independently of one another, an alkyl, cycloalkyl, an aromatic ring or a heteroaromatic ring, which may or may not be substituted by heteroatomic groups, which may comprise themselves at least one function selected from the group comprising the functions diazo, diazonium and azide.

5 - Process for securing valuable documents according to claim 3, characterized in that the active substance is a molecule having at least one diazonium function and corresponding to formula (II):

6 - Process for securing valuable documents according to claim 3, characterized in that the active substance is a molecule having at least one azide function and corresponding to formula (III):

R ₄ -N = N ⁺ = N- _(IΣI)

wherein R ₄ represents an alkali metal selected from the group consisting of sodium, potassium and lithium, an alkyl, cycloalkyl, an aromatic ring or a heteroaromatic ring, substituted or not by heteroatomic groups, which may themselves comprise at least one functional group chosen from the group comprising the diazo, diazonium and azide functions.

7 - Process for securing valuable documents according to any one of claims 4 to 6, characterized in that said heteroatomic groups comprise functions chosen from the group comprising the functions ester, ether, alcohol, amino, thiol, carboxylic acid, nitrile, aldehyde, nitro, and halogen.

8 - Process for securing valuable documents according to any one of claims 4 to 6, characterized in that the aromatic ring is a mono or polycyclic aryl radical.

9 - Process for securing valuable documents according to the preceding claim, characterized in that the monocyclic aryl radical is a phenyl radical substituted or not by one or more alkyl radicals.

10 - security method according to claim 6, characterized in that the active substance is sodium azide.

11 - Securing method according to claims 6 and 7, characterized in that the active substance corresponds to the formula (HIa):

12 - Securing method according to claims 6 and 7, characterized in that the active substance corresponds to the formula (HIb):

13 - Process for securing valuable documents according to any one of the preceding claims, characterized in that there is added to the active substance a chemical dopant accelerating the chemical reaction triggered by said external microwave radiation.

14 - Process for securing valuable documents according to any one of the preceding claims, characterized in that the integration of the active substance with valuable documents is achieved by incorporating said active substance into at least one of the constituent elements of said documents. valuable. 15 - Process for securing valuable documents according to the preceding claim, characterized in that the active substance is incorporated in the base support of the valuable documents, said support may be paper or plastic.

16 - Process for securing valuable documents according to any one of claims 1 to 13, characterized in that the active substance is incorporated in a varnish covering said valuable documents.

17 - Process for securing valuable documents according to any one of claims 1 to 13, characterized in that the active substance is incorporated in an ink printed on said valuable documents.

18 - Process for securing valuable documents according to any one of the preceding claims, characterized in that the securities documents are banknotes.

19 - Document of value likely to be exposed, especially in case of emergency, to external microwave radiation, characterized in that it comprises at least one active substance capable of releasing a gas following a chemical reaction of said active substance triggered by said external microwave radiation to which it is exposed, said gas being released in a quantity and at a rate such that the appearance of the valuable document is degraded, this degradation rendering said document unusable or legally identifiable.

20 - Document of value according to the preceding claim, characterized in that the active substance comprises at least one function capable of releasing a molecule of nitrogen during exposure to external microwave radiation, said function being selected from the group comprising diazo, diazonium and azide functions.

21 - Document of value according to the preceding claim, characterized in that the active substance is a molecule corresponding to the formula chosen from one of formulas I, II and III defined above.

22 - Document of value according to any one of claims 19 to 21, characterized in that it constitutes a bank note.