EP0412905B2 - Security paper - Google Patents

Description

The invention relates to security paper, in particular a bank note paper.

We already know from document CA-680 924 security papers in the form of check comprising on the surface a print with two different inks of same color, one of which is soluble in water and washable and the other is soluble in organic solvents, therefore insoluble in water and not washable, in order to display by erasing of washable ink a forgery message. As part of this document, surface printing is not safe and reliable because the falsifier can reprint the text and the impression of each ink is initially visible to the eye naked in transparency and reflection.

We already know papers that include strips or wires made of transparent film provided with a continuous metallic layer, for example aluminum vacuum deposited on polyester. Of such threads, when introduced into paper which is then printed, are barely seen by the public in reflected light and become much more apparent in transmitted light. These threads are intended to avoid that a counterfeiter, from common paper, imitates an authentic document, by printing on it paper a dark line on the surface. In this case of counterfeit, there is no difference between visibility of the line in reflection and transparency.

EP-A-279 880 describes a wire transparent with metallic micro-prints obtained for example by demetallizing areas not protected by varnish. The impressions are barely visible by reflection and more visible by transparency using a magnifying device.

In application EP-A-319 157, a paper with a thread provided with macro-prints in negative, which can be read by transparency at the naked eye.

These security threads aim to avoid counterfeiting, that is to say printing on non-paper authentic.

However, a new problem appears, namely falsification documents, including banknotes, by washing the original print and reprint false document on authentic paper.

Indeed, in some countries, all cuts tickets have the same format and are printed on the same paper. It therefore seems advantageous for a false to erase the impression of a low cut and reprint a high cut. Such washes printing are possible using solutions attacking printing ink, for example in the case of banknotes, alkaline solutions and / or very polar solvents.

The invention aims to provide a support comprising a security element betraying falsification.

It is known to introduce into the paper during its manufacturing, active chemical compounds intended to react to falsification. These compounds are intended to react to ad hoc falsification, for example modification a sum or signature on a check. Such papers have drawbacks, however. Indeed, it is possible to submit them to action extended with a liquid, water or organic solvent, to extract the active compound.

Document US-A-4 037 007 describes a security paper with boards comprising a substance capable of taking part to a coloring reaction, and when the document is checked with one or more reagents, the substance changes color. This substance only reacts a colorformer like those used in papers carbonless. It is an authentication process and not a process for betraying falsification.

Document EP-A-0 319 157 describes a safety wire which is manufactured by metallic deposit on the wire, printing using a resistant varnish and demetallization chemically. Once the wire as well realized, and this thread introduced into the paper, we don't call for demetallization to highlight falsification. The same is true in the documents US-A-4,652,015 and GB-A-2,213,908.

Document GB-A-1 095 286 describes a microprinted security thread. Some micro-prints may be sensitive to chemical reagents, this sensitivity allowing to appear reversibly in a given color the impressions. This brings an authentication feature more over safety but there is no way highlighting a forgery. The wire can be an aluminum sheet complex between two plastic sheets. This thread is clearly visible in the paper.

In the case of falsification of banknotes, it is necessary for the counterfeiter to erase completely duplex printing before reprint. To obtain a reprintable white surface, the infringer must submit the paper to action prolonged solutions attacking printing ink. So if the paper only contained compounds avoiding adulteration, these risk to be elected and not to fulfill their function.

Another object of the invention is therefore to provide a support comprising a security element which further retains some detectable security cues after attempting to whiten the surface of the support.

The invention therefore relates to a security support printable with betraying security features falsification. These security features are as they involve at least hidden means recognition of falsification.

These means of recognition of falsification are therefore invisible before attempted falsification, but become visible afterwards. They are also resistant to falsifying agents.

According to the best embodiment of the invention. A printable security support is provided comprising at least one security, arranged at least partially between the faces of the support, characterized by the fact that said security element consists of a support element coated with at least partially of a layer sensitive to falsifying agents, said element security also comprising means for recognizing falsification, consisting of an agent resistant to falsification agents, cooperating with said layer sensitive to falsifying agents so as to be invisible to the naked eye in transparency and in reflection before an attempt at falsification and to become visible after attack of said sensitive layer by said falsifying agent, thus allowing this recognition of falsification, said agent resistant to falsifying agents then possibly giving rise to a design or a model. The agent sensitive layer falsification is a layer sensitive to the agents chosen among the group of strong bases or solvents polar. The sensitive layer is, for example, a metal layer sensitive to alkalis such as aluminum. The resistant agent is, for example, an impression colorless or colored. This impression can be obtained from an ink which may contain a pigment chosen from the group of mineral pigments, organic, metallic. This impression can also be obtained by chemical deposition of a metal inert towards tampering agents. Preferably, the support element is flexible and is made of a material synthetic, for example polyester. According to a embodiment, the security element is constituted a polyester strip comprising on one side a metallic coating with resistant prints to falsifying agents. The security element may consist of a polyester strip comprising on one side a metallic coating and on the other face of prints resistant to falsifying agents. The security element may consist of a polyester strip comprising on one side an impression not sensitive to polar solvents and on the opposite side or the same side an impression sensitive to polar solvents.

The support is for example a sheet of paper obtained by the wet method and made up of cellulosic fibers, possibly synthetic fibers, binders, fillers. It can consist of a plastic sheet, possibly coated a layer to improve the impression.

• on recouvre une feuille flexible d'une couche métallique, par exemple de l'aluminium,
• on realise un impression sur une des faces de la feuille flexible à l'aide d'une encre résistant aux agents de falsification, ladite impression étant invisible par rapport à la couche métallicue.
• on coupe la feuille flexible ainsi revêtue et imprimée, pour réaliser des fibres, des fils continus ou des planchettes,
• on introduit les fibres, fils ou planchettes ainsi obtenus au moins partiellement à l'intérieur d'un support imprimable.

The invention further relates to a method of manufacturing a support according to which:

• a flexible sheet is covered with a metallic layer, for example aluminum,
• printing is carried out on one side of the flexible sheet using an ink resistant to falsifying agents, said printing being invisible with respect to the metal layer.
• the flexible sheet thus coated and printed is cut, to make fibers, continuous threads or boards,
• the fibers, threads or boards thus obtained are introduced at least partially inside a printable support.

• on recouvre une feuille flexible d'une couche métallique, par exemple de l'aluminium,
• on réalise une impression par dépôt chimique d'un métal, par exemple le nickel, sur l'une des faces de la feuille flexible, ladite impression étant invisible par rapport à la couche métallique,
• on coupe la feuille flexible ainsi revêtue et imprimée, pour réaliser des fibres, des fils continus ou des planchettes,
• on introduit les fibres, fils ou planchetes ainsi obtenues au moins partiellement à l'intérieur d'un support imprimable.

Finally, the invention relates to a method of manufacturing a support according to which:

• a flexible sheet is covered with a metallic layer, for example aluminum,
• printing is carried out by chemical deposition of a metal, for example nickel, on one of the faces of the flexible sheet, said printing being invisible with respect to the metal layer,
• the flexible sheet thus coated and printed is cut, to make fibers, continuous threads or boards,
• the fibers, threads or planchetes thus obtained are introduced at least partially inside a printable support.

The following description, next to the drawings and appended examples, will understand how the invention can be put into practice.

Figure 1 shows in cross section a security element according to the invention before introduction in the holder.

Figure 2 shows the appearance of a printed medium on the surface and with a security element of figure 1.

Figure 3 shows a support according to the figure 2, which was subjected to forgery agents.

Figures 4A and 4B are top views of the security element according to the invention before and after action of falsifying agents.

Figure 5, shows in section another mode of the security element according to the invention.

The security support 1 according to the invention is flat and printable. It has a security element 2 which is at least partially between the faces upper and lower of the support 1.

In Figure 1, there is shown a security element 2 which is completely arranged inside the support 1. However, this security element 2 is visible with the naked eye in transparency, i.e. in light transmitted. On the other hand, in reflected light, it is much less visible. So this security element 2 seems identical to a security element of the prior art, namely a covered polyester yarn of a continuous metallic layer. But this security element 2 includes recognition means 3 hidden falsification, these means being reactive to falsifying agents.

In Figure 2, there is shown the support 1 having on the surface impressions 3 which indicate for example the value 4 of the cutoff. According to a preferred embodiment of the invention, the element safety 2 is an element, for example a wire or a fiber, or a confetti, or a coated board a layer sensitive to falsifying agents and provided at least partially with a protective agent the sensitive layer, this agent being resistant to falsifying agents.

The skilled person is capable, knowing falsifying agents, to choose a sensitive layer agents and a protective agent resistant to same agents. So if the falsifying agents are basics, those skilled in the art may choose to coating the element (wire, fiber, confetti) with a dissolving metal to the bases and to provide the element with a layer partial or total of a base resistant varnish.

An exemplary embodiment is to coat a wire of polyester 5 (figure 1) with a layer 6 of aluminum and to print using a colorless varnish 7 above of the aluminum layer, this varnish being resistant at the bases, we get a dark wire 8 as in the figure 4A. We introduce wire in a paper or any other support. This wire is visible in transmitted light and much less visible in reflected light. The paper is then printed on the surface to form, by example, a bank note. When the counterfeiter will use a basic solution, possibly with detergent solutions, the aluminum layer will be dissolved and as the varnish is resistant at the bases, an impression 9 will appear, which will be visible transparently, while the paper becomes without surface printing. The wire will therefore not visible by the counterfeiter (Figure 3), in reflection. Through against, in transparency, the counterfeiter will clearly see an impression (as shown in the figure 4B). For example, if varnish printing forms the word "false", the infringer will be dissuaded from reprinting the ticket to change its value.

Another embodiment is to coat a polyester sheet entirely of aluminum, on a face, and completely of varnish on other face, this varnish being resistant to bases and being colored.

We cut this sheet into confetti or boards that we put in a paper, which is then printed on the surface. By transparency, these boards appear greyish, and if a counterfeiter tries to whiten the paper to remove the print the aluminum will be dissolved, while the colored varnish will remain. The boards will appear therefore colored, after attempt at falsification.

The varnish may include, according to another example, fluorescent dyes, resistant to bases. Thus the boards will appear gray before falsification and fluorescent after falsification.

The security elements according to the invention are distinguished elements of the prior art. In effect, the latter never use the layer couple sensitive to falsifying agents / resistant agent to falsifying agents. Application EP-A- 319 157 describes a wire which may include metallic inks as a print or wire that has been demetallized for example by means of a laser beam. This thread, once introduced into the paper, if it is subjected to a base, loses its metallic impression, but no case, it appears after falsification a means recognition of falsification, this means being invisible before tampering.

Another embodiment of the invention is the deposit 10 of aluminum on one side of polyester II (figure 5) and chemical deposition (to form a pattern) of a metal resistant to bases, for example nickel. When the wire is subjected to the bases, the aluminum is dissolves, while the nickel remains and lets appear the reason.

The security element can be inserted into a support which can be paper containing more or less synthetic or mineral fibers or support may be a sheet of synthetic material printable, such as the POLYART® sold by the plaintiff.

EXAMPLES EXAMPLE 1

• Résine Synolite 595   100 parties
• Terbutylperoxybenzoate   1 partie

A safety thread according to the invention is produced as follows: a polyester support 23 microns thick is metallized on one side. This metallization is obtained by spraying aluminum under vacuum. The thickness of aluminum deposited will depend on the desired opacity of the security wire; 700 angstroms for example. On the aluminized face of the wire are printed characters with an ink of the following composition:

• Synolite 595 resin 100 parts
• Terbutylperoxybenzoate 1 part

The printed characters are dried at 130 ° C. These characters are transparent. We thus obtain a solid safety wire, uniform color. This thread is introduced in paper by known techniques.

This paper with thread is intended for the printing of Bank notes. The attempt to launder the printing with an alkaline solution (sodium hydroxide at 3% added with a can of Teepol®) the dissolution of aluminum not protected by the varnish of printed characters. These characters become apparent and may be the word "false" which betrays falsification.

EXAMPLE 2

• Résine Synolite 595   100 parties
• Terbutylperoxybenzoate   1 partie
• Iriodine 100 (MERCK)   50 parties

On an aluminized wire, as described in Example 1, characters are printed on the non-aluminized face with the following ink:

• Synolite 595 resin 100 parts
• Terbutylperoxybenzoate 1 part
• Iriodine 100 (MERCK) 50 parts

These characters, after drying of the ink, have a metallic look and are very resistant to attack chemicals. The safety thread thus obtained is introduced in the homogeneous paper, and does not show any index. As before (example 1), the attack printing with an alkaline solution the dissolution of the entire aluminum layer located on one side of the wire and thus lets the text appear printed on the other side. According to the size of the characters printed, this text can only be read in transmission or visible in reflection.

EXAMPLE 3

A security thread is made as in the example 2 but using an ink consisting of a mixture of two inks: a white ink and a black ink. These inks have the particularity to resist well to chemical attacks. We can add to these inks any other mineral pigment to give them a hue special. Ink color is a function of tint characters that we want so that they become not discernible on the security thread after introduction in the paper. The attempt at falsification, as in the previous examples, will show the text printed as in example 2.

EXAMPLE 4

A safety thread according to the invention is obtained as follows: on one side of a polyester support 23 microns we print by chemical deposition of nickel by the methods known from the prior art (Bayprint process from the company BAYER for example). On the other side, a layer of aluminum is deposited (vacuum aluminization). This thread introduced into the paper seems quite common and does not appear no clue. This thread reacts as in the previous examples, attempts at falsification.

EXAMPLE 5

• Vernis vinylique   = 100 parties
• Bleu manolex   = 10 parties

A security thread according to the invention is obtained as follows: on one side of a 23 micron polyester support, printing is carried out using an ink of composition:

• Vinyl varnish = 100 parts
• Manolex blue = 10 parts

On the other side, an impression is made using an ink based on a known mineral blue pigment of the skilled person. This last impression are the hidden clues. This thread introduced into the paper appears uniformly blue. By washing the print with a polar solvent such as tetrahydrofuran, we elect the first ink revealing prints obtained with pigment-based ink minerals.

Claims (14)

1. Printable security medium comprising at least one security element, placed at least partly between the faces of the medium, characterized by the fact that the security element is constituted of a support element coated, at least partly, with a layer sensitive to falsifying agents, the said security element comprising also falsification recognition means constituted of an agent resistant to the falsifying agents, which co-operates with the said layer/sensitive to falsifying agents in such a way to be invisible to the naked eye by transmitted light and by retlected light, said resistant agent optionally forming a drawing or a pattern.
2. Medium according to claim 1, characterized by the fact that the layer sensitive to the falsifying agents, is a layer sensitive to the agents selected from the group of strong bases or polar solvents.
3. Medium according to one of claims 1 and 2, characterized by the fact that the sensible layer is a metal layer sensitive to the bases.
4. Medium according to one of claims 1 to 3, characterized by the fact that the resistant agent is a colorles, colored or fluorescent print.
5. Medium according to claim 4, characterized by the fact that the printing ink contains a pigment selected from the group of mineral, organic or metallic pigments.
6. Medium according to one of claims 1 to 5, characterized by the fact that the support element is flexible and constituted of a synthetic material.
7. Medium according to claim 6, characterized by the fact that the flexible support element is constituted of polyester.
8. Medium according to one of claims I to 7, characterized by the fact that the security element is constituted of a polyester strip provided on one face with a metallic coating sensitive to the bases, provided with prints resistant to the falsifying agents.
9. Medium according to one of claims 1 to 7, characterized by the fact that the security element is constituted of a polyester strip provided on one face with a metallic coating sensitive to the bases and on the other face with prints resistant to the falsifying agents.
10. Medium according to one of claims 1 to 7, characterized by the fact that the security element is constituted of a polyester strip provided on one face, with a print non-sensitive to polar solvents, and on the opposite face or on the same face, with a print sensitive to polar solvents.
11. Medium according to one of claims 1 to 10, characterized by the fact that it is constituted of a paper sheet obtained by wet route and constituted of cellulose fibers, optionally synthetic fibers, binders, fillers.
12. Medium according to one of claims 1 to 10, characterized by the fact that it is constituted of a sheet of synthetic material, optionally coated with a layer for improving the printing.
13. Process for the production of a medium according to claims 1 to 12, characterized by the fact that it consists in :

    coating a flexible sheet with a metallic layer sensitive to the bases,

    making a print on one of the faces of the flexible sheet, using an ink resistant to falsifying agents, said print being invisible with respect to the metallic layer,

    cutting the thus coated and printed flexible sheet, so as to produce fibers, continuous threads or planchettes,

    introducing the thus obtained fibers, threads or planchettes at least partly into a printable medium.
14. Process for the production of a medium according to one of claims 1 to 12, characterized by the fact that it consists in :

    coating a tlexible sheet with a metallic layer sensitive to bases,

    making a print by chemical deposition of nickel on one of the faces of the flexible sheet, said print being invisible with respect to the metallic coating,

    cutting the thus coated and printed flexible sheet, for producting fibers, continuous threads or planchettes,

    introducing the thus obtained fibers, threads or planchettes at least partly into a printable medium.

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