EP2761084B1 - Process for surface treatment of a banknote - Google Patents

Description

The bank note, originally called paper money, has existed since the ^10th century. This means of payment was introduced by the Chinese tea traders to avoid the transport of metallic coins. The first notes officially issued in France were first issued in 1803. Since its inception, paper money has been made using cotton. For some thirty years, however, cotton has yielded some ground to the polymer (s), which are more resistant according to its promoters. Whether the ticket support is cotton or polymer (s), its manufacture and valuation remain unchanged.

A succession of printing and securing processes (eg dry offset, wet offset, intaglio, flexography, screen printing or hot stamping ...) leads to a final product with high added value.

It is therefore essential to give increased longevity to this note, to prevent it from deteriorating too quickly.

If one wants to increase the longevity of these valuable prints, it is fundamental to understand the reasons that lead to the withdrawal of the notes.

The complexity of making a ticket is by nature an essential condition to discourage counterfeit attempts.

Effective deterrence is achieved by affixing several types of security at different levels.

The first-level secure elements are elements detectable with the naked eye, in daylight or artificial and do not require the use of a particular device.

The presence of a watermark, colored fibers, visible elements in transvision, or the tactile reliefs that produces a printing intaglio, are examples of elements of first level.

So-called second level security are detectable elements using technologically modest devices such as UV or IR lamps. This allows the authentication of banknotes within various organizations (shops, banking centers, etc.). We can thus distinguish patterns or texts printed in invisible ink but visible under ultraviolet or infrared radiation, fluorescent fibers, magnetic son etc ...

Finally, the third level of security requires sophisticated devices and, therefore, a high investment. It is mainly the central banks that examine these securities, such as the tracers present in the notes.

One of the necessary conditions to guarantee the role of these securities and their correct authentication over time is the good aging of the note. Central banks must exchange any returned ticket (various causes: dirt, tearing, mutilations ...) if it is identifiable at least 50%. It is therefore essential to be able to discern and control the many elements that make it up.

Central banks are thus showing more and more interest in more sustainable notes, both in terms of mechanical strength and chemical resistance.

In this way, a cleaner, more hygienic ticket with a longer life could be put into circulation while providing lower life cycle costs.

However, to create such a product, it is necessary to understand what actually weakens the notes, pushing for a withdrawal from circulation.

Several studies have been conducted by central banks to characterize the possible causes of banknote withdrawals. Among the various causes cited (DE HEIJ Hans, Durable Banknotes: An Overview In: Presentation of the BPC / Paper Committee to the BPC, May 2002, Prague.), One cause stands out from the others: the soiling.

It would be responsible for 60 to 80% of the withdrawal of bank notes from circulation. One of the main elements of this stain consists of human sebum, a naturally occurring fatty substance on the surface of the skin.

For this reason, professionals and especially paper manufacturers are trying to provide solutions such as "High Durability" papers or anti-fouling coatings, for example. They respectively increase the mechanical strength and chemical resistance of the notes.

Thus, different assemblies are proposed by the paper manufacturers. The differences vary between the composition of the fibrous mat (100% cotton, mixture of natural fibers, natural and synthetic fibers, polymer, etc.) and the coating / impregnation "sauces" used.

For example, natural fibers other than cotton may be flax or abaca, synthetic fibers are based on polyethylene, polypropylene. The support may even consist exclusively of bi-oriented polypropylene.

As for the anti-fouling coating, it may be for example sauces based on polyurethane or latex. These last examples are of course not exhaustive, each high durability paper having its own particularities according to the different suppliers.

But, ultimately, the final properties conferred on these papers are mixed. Indeed, some papers gain in terms of mechanical strength while others have improved in terms of anti-fouling properties but these media must retain the inalienable characteristic of printability.

These new papers, besides their higher cost, also have another weak point. As a result of the processing they have undergone in the manufacture of the paper, if the longevity of the media is increased, this does not guarantee the protection of the security impressions, fundamental aspect mentioned above.

In the document WO02051638 is described a technique which consists in performing a flexographic varnishing of the support at the end of the ticket manufacturing process. This varnish affixed superimposed improves the stain resistance of the note and thus protects the print in its entirety. By a single passage in the machine, without turning over, we protect the two faces of the bill, that is to say both the inks deposited and the support, soil. This UV-curing varnish is for example one of those proposed by Sicpa under the references SicpaProtect 889354 and 889405. Other references also work as the Schmidt Rhyner WESSCO Protector 36.298.42 varnishes and that of Actega TerraGloss UV Special Coating VP- HB 100-080.

A soil test (the procedure of which will be described later) is characterized as the differential of measurement of the luminance L of a soiled sample and of an unsalted control sample on an unprinted portion. Thus, when subjected to this test, a white wove paper formed of 100% cotton has a ΔL of about 20-30 units and this same paper varnished with the reference SicpaProtect 889354 printed in flexography, with an anilox of 6 / 6.5 cm ³ (ie about 2g / m ² transferred) a ΔL between 14 and 18, a gain of around 40%.

This result is already appreciable in itself but, unfortunately, the hydrophobic and oleophobic qualities of such a paper varnish with reference SicpaProtect 889354 are quite weak.

Moreover, it is known in the field of food packaging to want to protect them against the aggression of juices, sauces and other fats, at least until the products they contain will be consumed.

Solvay, for example, offers fluorine-based products whose anti-adherent properties are well known. Several references have the desired hydrophobicity and oleophobicity properties, in particular two aqueous dispersions based on perfluoro-polyether (PFPE, X - [- (CF ₂ -CF ₂ -O) _m - (CF ₂ O) _n -] -X). A first product, referenced FOMBLIN or 5134X contains PFPE-urethane, another product, referenced 5135X, contains PFPE phosphate ammonium salts. Another reference based on PFPE-urethane and containing organic solvents, is functionalized, that is to say that the base molecule also contains reactive chemical functions. It is capable of being mixed with matrices of varnish that can be polymerized under UV radiation and can therefore react by forming chemical bonds with the latter to reinforce its anchoring / adhesion. These products have been created to address health and environmental issues related to PFOA (perfluoroocatnoic acid) and PFOS (perfluorooctane sulfonate). The previously mentioned products, based on PFPE, contain neither PFOA nor PFOS and their degradation products either.

These products confer good barrier properties to oils and greases on paper and / or cardboard substrates. They are both used as surface treatment, applicable by flexography, rotogravure or any other usual method of coating.

The deposition on the surface creates an invisible chemical barrier of PFPE. These references are commonly used in the food packaging industry (eg animal food bag, pizza boxes). In addition, their accreditation to food contact attests to their safety.

In the WO 2009/077536 is described a safety document manufacturing technique using perfluoro (alkyl vinyl ether) s including.

The present applicant therefore proposes to remedy the drawbacks mentioned above with regard to varnishes for fiduciary use by a process which makes it possible to reinforce all the properties governing the longevity of a note, namely the resistance to soiling, the hydrophobicity , oleophobia, so as to reduce the retention of macroscopic particles of dirt, to repel, thanks to quantifiable barrier effects, the water of sweat and the fatty substances of sebum.

Thus, the present invention relates to a method of surface treatment of a banknote which comprises, at least on one of its opposite faces, at least one impression consisting of at least one pattern, this face and its printing. associated with being coated with a transparent protective coating, characterized by the fact that a coating containing a varnish and an organic chemical compound incorporating fluorine atoms in the form of at least a perfluoro-polyether group, on said face, and that is proceeded to its drying.

• l'ensemble de l'imprimé de valeur (c'est à dire le support et ses impressions) est protégé ;
• la résistance à la salissure est plus performante que celle de la méthode de vernissage actuelle ;
• les propriétés d'hydrophobie sont plus performantes que celle de la méthode de vernissage actuelle ;
• les propriétés d'oléophobie sont plus performantes que celle de la méthode de vernissage actuelle standard décrite dans le présent document;
• l'amélioration des propriétés susmentionnées ne se fait pas au détriment de l'aspect économique et n'utilise pas des procédés physiques complexes renchérissant de manière importante voire insupportable le coût de fabrication du billet ;
• le traitement est compatible avec les techniques d'impression usuelle, c'est-à-dire que le revêtement est lui-même imprimable ;
• le traitement peut être appliqué par le procédé d'impression flexographique, d'héliogravure ou de sérigraphie ;
• le traitement, une fois le document de sécurité fabriqué et son revêtement sec, est compatible avec un contact épidermique, sans être connu toxique ou allergène.

Thanks to the implementation of this technique, the following results / advantages / characteristics are obtained:

• the whole value print (ie the medium and its prints) is protected;
• the resistance to soiling is more efficient than that of the current coating method;
• the hydrophobicity properties are more efficient than that of the current coating method;
• the oleophobia properties are more efficient than the current standard coating method described in this document;
• the improvement of the above-mentioned properties is not detrimental to the economic aspect and does not use complex physical processes which make the cost of making the ticket significantly or even unbearably expensive;
• the treatment is compatible with the usual printing techniques, that is to say that the coating is itself printable;
• the treatment can be applied by the process of flexographic printing, gravure printing or screen printing;
• the treatment, once the safety document manufactured and its dry coating, is compatible with an epidermal contact, without being known toxic or allergenic.

• ledit revêtement est imprimé sur ladite face sous la forme de deux couches distinctes, à savoir d'abord une première couche de vernis et ensuite une seconde contenant ledit composé chimique organique incorporant des atomes de fluor sous forme d'au moins un groupement perfluoro-polyéther, dans une base aqueuse ou dans une base solvant ;
• l'on procède au séchage dudit vernis sous un rayonnement ultraviolet ;
• ledit composé chimique organique incorporant des atomes de fluor sous forme d'au moins un groupement perfluoro-polyéther est dans une base solvant compatible avec la matrice dudit vernis avec lequel il est mélangé, sous une forme fonctionnalisée c'est-à-dire capable d'interagir avec cette dernière en formant des liaisons chimiques afin de renforcer son ancrage/accroche ;
• l'on procède au séchage de la seconde couche par rayonnement ultraviolet ;
• ledit composé chimique est dans une base aqueuse ;
• l'on procède au séchage sans altération ni modification chimique dudit composé chimique organique, par séchage sous air chaud de la base aqueuse ;
• ledit revêtement est imprimé sur ladite face sous la forme d'un mélange dudit vernis, polymérisable sous rayonnement ultraviolet, et dudit composé chimique organique incorporant des atomes de fluor sous forme d'au moins un groupement perfluoro-polyéther, dans une base solvant compatible avec la matrice dudit vernis avec lequel il est mélangé, sous une forme fonctionnalisée c'est-à-dire capable d'interagir avec cette dernière en formant des liaisons chimiques afin de renforcer son ancrage/accroche ;
• l'on procède au séchage dudit mélange sous rayonnement ultra-violet ;
• ledit revêtement incorpore au moins un agent bactéricide et/ou antifongique et/ou antiviral ;
• ledit agent est incorporé dans ladite seconde couche.

According to other advantageous and nonlimiting features of this process:

• said coating is printed on said face in the form of two distinct layers, namely firstly a first layer of varnish and then a second containing said organic chemical compound incorporating fluorine atoms in the form of at least one perfluoro-polyether group in an aqueous base or in a solvent base;
• drying said varnish under ultraviolet radiation;
• said organic chemical compound incorporating fluorine atoms in the form of at least one perfluoro-polyether group is in a solvent base compatible with the matrix of said varnish with which it is mixed, in a functionalized form that is to say capable of interact with the latter by forming chemical bonds to reinforce its anchoring / hooking;
• the second layer is dried by ultraviolet radiation;
• said chemical compound is in an aqueous base;
• the drying is carried out without alteration or chemical modification of said organic chemical compound, by drying in hot air of the aqueous base;
• said coating is printed on said face in the form of a mixture of said ultraviolet-radiation curable polish and said organic chemical compound incorporating fluorine atoms as at least one perfluoro-polyether moiety in a solvent base compatible with the matrix of said varnish with which it is mixed, in a functionalized form that is to say capable of interacting with the latter by forming chemical bonds to strengthen its anchoring / hooking;
• drying said mixture under ultraviolet radiation;
• said coating incorporates at least one bactericidal and / or antifungal and / or antiviral agent;
• said agent is incorporated in said second layer.

• la figure 1 est une vue de dessus, partielle et schématique, d'un billet de banque avant mise en oeuvre du procédé ;
• la figure 2 est une vue simplifiée, en coupe, selon le plan II-II de la figure 1, du billet de banque obtenu conformément à une première étape du procédé selon l'invention ;
• la figure 3 est également une vue simplifiée, en coupe selon le même plan, du billet de banque obtenu après la mise en oeuvre de la deuxième étape du procédé selon l'invention ;
• la figure 4 est une vue analogue à celle de la figure 1, le billet présentant en plus un motif en forme de F réalisé en vernis brillant ;
• la figure 5 est analogue à la figure 2 du mode de réalisation de la figure 4 ;
• la figure 6 est analogue à la figure 3 du mode de réalisation de la figure 4.

Other features and advantages of the invention will appear on reading the detailed description which follows. It will be made with reference to the accompanying drawings in which:

• the figure 1 is a top view, partial and schematic, of a banknote before implementation of the method;
• the figure 2 is a simplified view, in section, according to plan II-II of the figure 1 of the banknote obtained according to a first step of the method according to the invention;
• the figure 3 is also a simplified view, in section on the same plane, of the bank note obtained after the implementation of the second step of the method according to the invention;
• the figure 4 is a view similar to that of the figure 1 , the note further having a F-shaped pattern made of gloss varnish;
• the figure 5 is analogous to the figure 2 of the embodiment of the figure 4 ;
• the figure 6 is analogous to the figure 3 of the embodiment of the figure 4 .

By the term "varnish" is meant varnishes with infra-red drying / hot air and varnishes with UV drying.

Preferably, it is acrylic varnish aqueous base for the first, and epoxy or acrylate-based varnish and solvents for the second.

An IR / hot air drying varnish is for example that of the Sicpa company such as Sicpaprotect 803688W (acrylic polymer).

For the UV-curing varnish, one can for example use the Sicpapotect 889354 based on monomers of the family of cycloaliphatic epoxides such as "Chissonox 221 Monomer" and which polymerises to give a polyepoxide matrix by means of initiators such as sodium salts. onium (eg substituted sulfonium cation and its anion) activated under UV.

Another varnish such as "Wessco Protector 36.298.42" by Schmidt Rhyner polymerizes under UV (radical mechanism) by giving a polyacrylate matrix from acrylate compounds such as, in addition, trymethylolpropane triacrylate.

The "Actega terraGloss UV Special Coating VP-HB 100-080" varnish also polymerizes by giving a polyacrylate matrix from, inter alia, unsaturated acrylic resin.

By "printing consisting of a pattern" is meant any printed element, whatever the ink used, which forms any figure, for example in the form of a flat surface or not, this figure may in particular be inter alia a character. alphanumeric.

To the figure 1 is shown very schematically a document 1, in this case a bank note consisting of a support 2 paper or cotton fibers, for example, whose opposite upper and lower faces are referenced 20 and 21.

On the upper face 20 are printed, by any technique known to those skilled in the art, patterns 3 which here respectively consist, in the value of the note (here 100), a guilloche and a portrait.

This pattern may have been printed using a so-called security ink.

Other impressions can of course appear on the face 20.

Of course, the opposite face 21 may also comprise identical, similar or different impressions.

Referring now to the figure 2 it is found that the face 20 is coated with a layer of clear varnish 4, whose definition was given above.

Of course, the figure 2 as well as the following are given for illustrative purposes only, so that the proportions, especially in thickness, do not reflect reality. Furthermore, only the face 20 is coated with a varnish for explanation and not to unnecessarily burden the figures. Of course, in reality and for optimal protection, the two opposite faces 20 and 21 are coated.

This varnish layer was printed according to the following operating conditions and described above (varnish with reference SicpaProtect 889354 printed in flexography, with anilox of 6 / 6.5 cm ³ (ie approximately 2 g / m ² transferred) and dried under UV lamps HÔNLE mercury spectrum 200 W / cm at 65% of their power).

After drying, an additional layer consisting of an organic chemical compound incorporating fluorine atoms in the form of at least one PFPE perfluoro-polyether group is flexo printed with anilox identical to those described above on layer 4. or at least one of its derivatives in an aqueous base version. After drying of the layer 5, the two layers 4 and 5 then form a coating R.

The drying of the layer 5 is carried out by evaporation under an infrared / hot air GRAFIX lamp at 150 ° C.

In a different embodiment, said drying consists of ultraviolet radiation drying of the same type as that mentioned above, especially when the organic chemical compound incorporating fluorine atoms in the form of at least one PFPE group and compatible with drying under UV radiation, is mixed directly with said varnish.

The embodiment of the Figures 4 to 6 is similar to that described previously. It differs only in that an "F" -shaped pattern 31 is printed in the form of a gloss-like region on a matte background or surrounded by a matt background, in accordance with the patent application. French published under number 2 958 209 .

According to a variant not shown, the varnish and the organic chemical compound incorporating fluorine atoms are printed in the form of a single layer.

The nonstick properties of the R coating reduce the chances of interaction and attachment of microscopic living pathogens such as bacteria and fungi, thereby inhibiting their proliferation.

Moreover, it is possible to envisage that biocidal agents be inserted in the dopant state in the layer 5 in order not to oppose a "passive" protection to the pathogenic aggressions as mentioned above, but a protection " active "as is possible for example with silver ions [cf. N. Stobie et al. : Silver Doped Perfluoropolyether-Urethane Coatings: Antibacterial Activity and Surface Analysis. Colloids and Surfaces B: Biointerfaces Vol 72,1 (2009), pp 62-67 ].

The interest of providing active protection to the coating R is obvious because its implementation is at the final stage of printing the ticket, just before its formatting finished. This goes against the solution proposed in EP 03740577 (ARJOWIIGGINS) which describes the protection of the support alone by a couple of biocides and ignores the antagonistic barrier effect of printing inks (Offset, Soft Size, Silkscreen ...) and "foils" (polyester tape) on the actual effectiveness of the biocidal treatment.

Work has been done to observe the effects of these impressions on bank notes.

The soil resistance was tested according to the dry soil test (Fritsch). It is a vibrating apparatus where small glass beads are spread and incrust on a test piece of paper a messy composition based on sand, peat, activated carbon, flour, and mono-oleate glycerin (fat present in sebum). The test lasts 15 minutes. As stated above, the luminance of an initially white area is measured several times before and after exposure to the messy composition. The difference obtained or ΔL, allows to characterize the grip of the stain on the note: the smaller it is, the better is the resistance to dry dirt.

Hydrophobicity is characterized as resistance to penetration of water but also its ability to repel the latter surface called water repellency. Resistance to water penetration is therefore measured using the Cobb test (60 s). This is the amount of water absorbed by the support in g / m ² through a cylindrical impregnation template for a period of 60 seconds. This is an otherwise common test in the paper industry to characterize paper absorption. There is also a Cobb at 300 seconds, this allows to see if the effect of the layer is still present after a longer exposure time under water.

As for the water repellency, it is the natural propensity of the paper to make that the water flows in the form of drops on the surface of a paper, by simple "gravity" when the substrate is inclined. This is a visual test that has been correlated with contact angle measurements (θ) of a water droplet at 500 μs (from which the surface tension values are also derived) . It is indeed at this moment that one can consider that this drop is stabilized on the surface of the paper.

Oleophobia is measured by fat exposure tests. A first method called "Kit Test" uses a mixture of castor oil (fats) and high-boiling solvents, namely toluene (aromatic solvent) and n-heptane (aliphatic solvent).

Depending on the different proportions of the aforementioned products, a composition is obtained whose viscosity and surface vary inversely with its aggressiveness, that is to say, its capacity of impregnation.

A composition rich in castor oil is at the bottom of the scale, while a composition rich in heavy solvents is at the top of the scale.

There are 12 compositions and it is admitted that a score greater than or equal to 6 confers a satisfactory barrier to fats. The evaluation is done visually.

Another test has been implemented, this is the fatty acid test (GA). The principle is the same as previously mentioned but the composition is a mixture of fatty acids, one of which is present in sebum. It is a mixture in different proportions of castor oil (heavy fraction), oleic acid (intermediate fraction) and octanoic acid (light fraction) with decreasing viscosities. The test is carried out at 20 ° C. and at 60 ° C.

There are 11 compositions to test and the results are also expressed in the form of visual notation. The higher up the scale, the greater the barrier effect on fatty substances, which corresponds to a decrease in the composition of the proportion of castor oil, an increase then a decrease in oleic acid and finally an increase octanoic acid.

The following tables record the results of tests for a valuable print with a 100% cotton vellum backing, printed in the last pass in flexography with a SICPAPROTECT 889354 varnish on 6 / 6.5 cm anilox ³ (front / back) and dried under UV HÖNLE mercury-spectrum lamps 200 W / cm at 65% of their power, then with reference SOLVAY 5134 X aqueous base dried in hot air under ovens equipped with infrared lamps / GRAFIX hot air at 150 ° C.

Unexpectedly, the results obtained by treating the cotton note paper with 5134 X alone is unsatisfactory (Table 1). Thus, the soil test, surprisingly, is less good than when the supports are only varnished with SICPAPROTECT 889354 and if the hydrophobicity is excellent, the oleophobic properties are in turn unattractive.

It is furthermore confirmed that the paper without treatment has none of the desired properties and that the paper only varnishes, if it has proven anti-fouling properties is only slightly hydrophobic and not oleophobic.

On the other hand, the combination of the varnish and the treatment based on fluorinated product gives unexpected results. A real functional synergy is obtained by combining, in this order, the varnish and the product 5134 X (Table 2). Thus significant gains are observed in antifouling and the properties of hydrophobicity and oleophobia are present and it is not a simple addition of the properties attached to each of the constituents.

Durability tests were conducted on the previous samples and it appears that the protection of the coating R is preserved after immersion tests for 30 minutes with polar solvents (ethanol, acetone, diethylene glycol), apolar (xylene, petroleum), chlorinated (tetrachlorethylene), synthetic sweat, acids diluted to 5% (acetic, hydrochloric, sulfuric), soda diluted to 5%, oxidizers diluted to 5% (sodium hypochlorite, hydrogen peroxide) ), with hot water (100 ° C), industrial laundry (St Marc, Persil). Furthermore, the coating R retains these properties after a light fastness test (48h at Suntest), exposure to heat (120 ° C, 30 min) and wet wrinkling. Finally, after a Fritsch soil test as previously described the properties of hydrophobicity and oleophobia are preserved.

Other results, not shown here, have shown that it was possible to increase these gains to obtain soil resistance values with a ΔL ≤ 5, a total water-repellency, a contact angle θ ≥ 110 ° , a test kit rating ≥ 7 and a test score at AG ≥ 5, based on the ratio of the quantities deposited between the varnish and the 5134X product. It can furthermore be argued that a surface pretreatment, for example of the corona type, either before the UV-drying varnish or before the drying of the second aqueous-based varnish containing the product 5134 X, would also have a positive effect on the results stated herein. -before.

Performance tests were conducted with the other Solvay products mentioned above and led to very similar protection results. Table 1 ΔL (Fritsch) Cobb 60s repellence * Contact angle Test Kit (max 12) Test AG (max 11) ** Printed only 27.6 ± 1.4 ~ 60 g / m ² 1 37 ° ± 3 0 0 Printed calendered *** 2 faces and varnish 16.1 ± 2.3 ~ 50 g / m ² 2 75 ° ± 4 1 0 2-sided calfskin print treated with 5134 X 21.2 ± 1.7 2 g / m ² < 3 123 ° ± 3 3 0 * 1 does not shed, fast absorption; 2 weak depedency, absorption; 3 total depedance, no absorption
** at 20 ° C
*** means that the document is printed twice in intaglio printing, first on the back and a second time on the front ΔL (Fritsch) Cobb 60s repellence Contact angle Test Kit (max 12) AG test (max 11) Printed only 27.6 ± 1.4 ~ 60 g / m ² 1 37 ° ± 3 0 0 2-sided and varnished calendered print 16.1 ± 2.3 ~ 50 g / m ² 2 75 ° ± 4 1 0 Calendered 2 sided print, varnished and treated with 5134 X 8.9 ± 2.1 g / m ² < 3 110 ° ± 1 7 8

Claims (9)

1. A process for treating the surface of a banknote (1) which comprises, at least on one of its opposite faces (20, 21), at least one printed item consisting of at least one design (3), this face (20, 21) and its associated printed item (3) being covered by a transparent protective coating (R), characterised in that a coating is applied by printing containing a varnish and an organic chemical compound incorporating fluorine atoms in the form of at least one perfluoro-polyether group (PFPE), on said face (20, 21), and in that its drying is carried out.
2. The process as claimed in Claim 1, characterised in that said coating (R) is printed on said face in the form of two distinct layers, specifically first a first layer de varnish (4) and then a second (5) containing said organic chemical compound incorporating fluorine atoms in the form of at least one perfluoro-polyether group (PFPE), in an aqueous base or in a solvent base.
3. The process as claimed in Claim 2, characterised in that drying of said varnish is performed under ultraviolet radiation.
4. The process as claimed in Claim 2 or 3 in which said organic chemical compound incorporating fluorine atoms in the form of at least one perfluoro-polyether group (PFPE) is in a solvent base compatible with the matrix of said varnish with which it is mixed, in functionalised form that is, capable of interacting with the latter by forming chemical bonds to reinforce its anchoring/grip, characterised in that drying of the second layer (5) is performed by ultraviolet radiation.
5. The process as claimed in Claim 2 or 3 in which said chemical compound is in an aqueous base, characterised in that the drying is performed without alteration or chemical modification of said organic chemical compound, by drying in hot air.
6. The process as claimed in Claim 1, characterised in that said coating (R) is printed on said face in the form of a mixture of said polymerisable varnish under ultraviolet radiation and of said organic chemical compound incorporating fluorine atoms in the form of at least one perfluoro-polyether group (PFPE), in a solvent base compatible with the matrix of said varnish with which it is mixed, in functionalised form, that is, capable of interacting with the latter by forming chemical bonds to reinforce its anchoring/grip.
7. The process as claimed in Claim 6, characterised in that drying of said mixture is performed under ultraviolet radiation.
8. The process as claimed in any one of the preceding claims, characterised in that said coating (R) incorporates at least one bactericidal and/or antifungal and/or antiviral agent.
9. The process as claimed in Claims 2 and 8 taken in combination, characterised in that said agent is incorporated in said second layer (5).

Images