Protective varnish, in particular for security documents

Abstract

To provide a varnish formulation that makes it possible to confer, besides the basic property of reinforcing resistance to soiling, resistance to microscopic soiling and more particularly protection against bacteria, microscopic fungi, in particular yeasts, and viruses.SOLUTION: A radiation-curable protective varnish comprising at least one compound curable by cationic means or radical means, at least one biocide comprising iodopropynyl butylcarbamate, and at least one metal selected from silver, copper, zinc, and mixtures thereof, where the metal is in the state of zero oxidation level and in a supported particulate form.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to the field of security documents, more particularly banknotes.

[0002] The invention also relates to the field of varnishes, and in particular to the field of overprint varnishes, which make it possible to impart an enhanced level of durability to banknotes or security documents by increasing their resistance to smearing.

[0003] More particularly, the present invention relates to varnish formulations which, in addition to the basic property of enhancing resistance to fouling, make it possible to provide resistance to microscopic fouling, more particularly protection from bacteria, microscopic fungi, especially yeasts, and viruses. [Background technology]

[0004] Banknotes are among the most widely exchanged information documents in the world. Repeated exchanges, use, and the environmental conditions of their circulation have an effect on their physical deterioration, and frequently used banknotes are often highly soiled or even microbiologically contaminated. Excessive soiling impairs the visibility of banknote authentication marks, forcing central banks to withdraw banknotes from circulation and reissue cleaner banknotes. One anticipated solution to reduce the frequency of renewal consists of applying a varnish, commonly an overprint varnish, to the surface of printed banknotes once most of the printing process has been performed, which allows the banknote to have enhanced resistance to soiling. However, this solution is insufficient to effectively combat microscopic soiling and provide protection from microorganisms. Now, many studies have shown that banknotes in circulation, due to their handling and exchange from hand to hand, are carriers of sometimes pathogenic microorganisms, in particular bacteria, microfungi, in particular yeasts, and viruses. Furthermore, the presence of mold can deteriorate cellulose substrates.

[0005] Therefore, there remains a need for an effective means of imparting resistance to banknotes to the banknotes that is combined with effective antibacterial, antifungal and antiviral protection.

[0006] Indeed, solutions already exist that make it possible to impart antimicrobial properties to banknote substrates (see FR 2945180 and FR 2967074). Unfortunately, the currently available solutions essentially require antimicrobial solutions based on the combination of biocidal active agents formulated in an aqueous medium, the active agents themselves often being in aqueous dispersions or emulsions. Here, the formulation in a matrix of crosslinked resins, as described in particular in EP 2761084, does not allow for aqueous compounds.

[0007] Furthermore, curing the applied varnish generally requires a UV crosslinking procedure, which requires irradiating the coated substrate with high-intensity UV light. The antimicrobial active agent used here must not be degraded during this step of the printing varnish treatment process. The antimicrobial active agent must not be photosensitive.

[0008] Furthermore, the distribution of the antimicrobial active agent used within the varnish film must be very uniform so that the surface interface of the varnish-printed substrate, i.e. the outer surface layer of the document, has sufficient biocidal activity. Summary of the Invention [Problem to be solved by the invention]

[0009] The present invention has as its very object to propose a new varnish, in particular an overprint varnish, which meets all of these requirements. [Means for solving the problem]

[0010] The present invention therefore primarily relates to a protective varnish curable by radiation, in particular UV, comprising at least one compound curable by cationic or radical means and at least one metal selected from silver, copper, zinc and mixtures thereof, characterized in that said metal is in the zero oxidation state and in the form of supported particles.

[0011] The varnish according to the invention additionally comprises at least one fungicide.

[0012] The present invention therefore provides a protective varnish curable by radiation, in particular UV, which varnish comprises at least one compound curable by cationic or radical means; at least one fungicide including at least iodopropynyl butylcarbamate, or IPBC; at least one metal selected from silver, copper, zinc and mixtures thereof; wherein the metal is in the zero oxidation state and in the form of supported particles.

[0013] In particular, the varnish has biocidal activity, in particular at least bactericidal or bacteriostatic activity, preferably at least bactericidal activity. More generally, the varnish has bactericidal, bacteriostatic and / or antiviral activity, preferably bactericidal and antiviral activity.

[0014] According to a preferred variant, the metal in its zero oxidation state is supported by an inorganic particulate material, preferably a particulate phosphate glass.

[0015] According to another preferred variant, the metal comprises at least silver.

[0016] As will be apparent from one or more of the examples provided below, the inventors have found that, in accordance with the present invention, the zero-degree supported metal does not interfere with the UV irradiation process required to cure the varnish.

[0017] Moreover, the inventors have found that varnishes incorporating these materials can still have the expected or even improved durability, particularly stain resistance, and remain transparent.

[0018] Finally, the inventors have found that, contrary to all expectations, these metals at zero degrees can generate ionic metal species in such an environment and in contact with ambient moisture that are endowed with the required bactericidal activity.

[0019] Furthermore, as demonstrated in one or more of the examples, the combination of IPBC with this metal in its zero oxidation state and in supported particle form advantageously makes it possible to improve the antimicrobial properties of the varnish.

[0020] The present invention also relates to an object, one of whose outer surfaces is entirely or partially coated with a cured varnish deposit formed from a curable varnish according to the invention. The object is intended to be touched or handled, for example, a handle, a button, a touch screen, packaging, an information carrier, in particular a security document or element, preferably a banknote. The object is made of a material selected from the group consisting of glass plates, paper, cardboard, plastic, fabrics, and optical structures, in particular layers of functional resins or combinations of one or more layers.

[0021] The invention relates in particular to a security element or document, for example made of paper or plastic, coated on all or part of one of its one or more outer surfaces with a hardened varnish deposit formed from a curable varnish according to the invention.

[0022] The present invention preferably relates to a security document having one of its one or more outer surfaces coated, in whole or in part, with a hardened varnish deposit formed from a curable varnish according to the invention.

[0023] More particularly, the security document is surface treated on at least one of its one or more faces with a cured varnish film formed from the curable varnish according to the invention.

[0024] According to a preferred variant, this document incorporates one or more security elements and is advantageously a banknote.

[0025] The present invention also provides a method of making such an object, comprising the steps of: providing the object; contacting the surface of the object to be treated with a varnish according to the present invention under conditions effective to form a curable varnish deposit on said surface; and exposing the deposit to radiation to harden the deposit. The method includes at least the steps of:

[0026] The invention more particularly relates to a method for producing a security document of this kind, comprising: Prepare the above security documents, contacting the surface of the document to be treated with a varnish according to the present invention under conditions effective to form a curable varnish deposit on said surface; and exposing the deposit to radiation to harden the deposit. The method includes at least the steps of:

[0027] Bringing the surface to be treated of the object, in particular a security document, into contact with the varnish according to the invention can be carried out by a printing process, in particular flexographic, gravure or serigraphic, by spraying, by application by brush or by any other coating process.

[0028] Furthermore, the present invention relates to the use of a varnish according to the invention for producing a protective coating or layer on a security document, preferably a banknote.

[0029] The invention further relates to the use of a varnish according to the invention for improving the resistance to fouling of security documents, preferably banknotes.

[0030] The invention also relates to the use of a varnish according to the invention for imparting antimicrobial properties to security documents, preferably banknotes. DETAILED DESCRIPTION OF THE INVENTION

[0031] Supported metals in zero oxidation state In the sense of the present invention, a metal in the zero oxidation state is a metal whose atoms are in non-ionic form. In this specification, the expressions "zero metal", "metal" and "metal in the zero oxidation state" will be used to mean this non-oxidized state of the metal.

[0032] As stated above, the metal is selected from silver, zinc, copper and mixtures thereof.

[0033] According to a preferred variant, the zero metal comprises at least silver, and in particular consists of silver.

[0034] In the sense of the present invention, the expression "in supported particle form" indicates that the metal is supported by an inorganic particulate material. More particularly, the metal is immobilized at the surface and, if applicable, in the depth of this material. This material may in particular represent the matrix in which the metal is dispersed.

[0035] The zero metal-containing inorganic material may be selected from zeolites and glasses, especially phosphate glasses.

[0036] Preferably, the material is glass, more particularly phosphate glass, which advantageously has great stability during the UV cross-linking process.

[0037] The sufficiently small particle size, i.e., about 10 microns in size, of the zero metal-containing or doped inorganic material, and its essentially transparent nature, allow the cured varnish film to retain its transparency and ensure uniform antibacterial protection. Advantageously, in the case of overprint varnishes, and as will be demonstrated in one or more examples given below, no changes are observed in the print reproduction and gloss of the banknote. In fact, it is known that automatic banknote sorting machines (BPS) are "hampered" by excessive gloss.

[0038] Therefore, the particle size of the zero metal loaded or doped material is preferably less than 10 μm, preferably less than 5 μm. The particle size can be measured in particular by SEM imaging or by DLS (dynamic light scattering). The particle size can more particularly be defined by the diameter D98, i.e., the diameter below which 98% of the particles by weight have a size smaller than the diameter mentioned above.

[0039] The loading of the material with metals in the zero oxidation state varies from 0.5 wt. % to 3 wt. %, in particular from 1.0 wt. % to 2.5 wt. %, relative to the total weight of the material.

[0040] According to one embodiment, the varnish may also contain other mineral particles whose function may in particular be to adjust the gloss level of the finished varnish film, in particular silica particles. This is very particularly relevant in the context of overprint varnishes.

[0041] As demonstrated by one or more of the examples provided below, cured varnishes containing zero metal loaded particles and IPBC according to the present invention exhibit expected bactericidal and virucidal properties.

[0042] According to a preferred variant, the varnish comprises metallic silver supported on granular material made of glass, preferably phosphate glass.

[0043] More precisely, the metallic silver is in the form of silver particles in a matrix of phosphate glass. This matrix is ​​composed of silver ions, Ag + and therefore the silver ions Ag + This has the advantage of allowing the passage / movement of

[0044] These Ags have bactericidal activity +The ions are generated by contacting silver in zero oxidation state, dispersed in the varnish, with ambient moisture or with splashes, especially from spits, during contamination periods.

[0045] This type of material is sold in particular under the name Ultrafresh CA16 by the company Thomson Research Associates Inc.

[0046] varnish The term "protective varnish" means a varnish that is useful for imparting resistance to staining, advantageously combined with antimicrobial protection, to a security document on whose surface the varnish is applied.

[0047] In the sense of the present invention, the term "antimicrobial" describes biocidal, especially bactericidal, fungicidal, especially yeasticidal, virucidal and / or algicidal activity, i.e., killing microorganisms of interest, but also bacteriostatic and / or fungistatic activity, i.e., inhibiting the growth of bacteria and microfungi.

[0048] The expression "irradiation-curable varnish" in the sense of the present invention covers varnishes which solidify under infrared / hot air and UV drying.

[0049] To this end, the varnishes considered according to the invention comprise one or more hardenable compounds.

[0050] In the sense of the present invention, a curable compound is a compound that is capable of polymerizing, crosslinking or, if applicable, undergoing polycondensation with other compounds in response to a stimulus, in this case heating by infrared or UV radiation, and, if necessary, the presence of auxiliary compounds called initiators, and thus irreversibly forming a film that is solid under ambient conditions (room temperature, irradiation by sunlight, etc.).

[0051] Advantageously, the curable compound is a varnish that is curable by UV-visible radiation, in other words, the curable compound solidifies under UV drying.

[0052] For example, acrylic varnishes, varnishes containing epoxide groups or varnishes containing acrylate groups are particularly suitable. The curable compound is preferably a varnish containing acrylate groups.

[0053] The curable compounds may in particular be varnishes based on monomers of polyalkyl acrylates, varnishes based on unsaturated acrylic resins, or varnishes based on monomers of cycloaliphatic epoxides, the latter of which polymerize to give a polyepoxide matrix with the aid of an initiator, in particular a photoinitiator, such as an onium salt activated under UV light.

[0054] These compounds may, if desired, be further combined with free radical photoinitiators, such as onium salts, especially sulfonium cations and anions, substituted, if appropriate.

[0055] Thus, the varnish may further comprise a free radical photoinitiator.

[0056] The curable varnish according to the invention is therefore preferably a precursor to a polyepoxide- or polyacrylate-based, more preferably polyepoxide-based, cured varnish.

[0057] As examples of these varnishes, we may mention, for example, the polyepoxide varnish sold under the name "Sicpaprotect" by Sicpa (reference number 889368 for paper substrates or reference number 889354 for polymer substrates) and the polyacrylate varnish sold under the name "Wessco Protector 36.389.19" by Schmidt Rhyner.

[0058] According to a preferred variant, the varnish according to the invention is a cationic varnish.

[0059] According to another preferred variant, the varnish according to the invention is an overprint varnish, particularly useful for security documents.

[0060] The varnish according to the invention is advantageously fluid in order to easily form a film by application onto the surface to be treated.

[0061] For example, the varnish according to the invention can be deposited on the surface of the substrate by any suitable method, and for example by the methods of flexographic, gravure or screen printing, or even by the methods of air knife coating, curtain coating or roller coating. The viscosity of the varnish according to the invention can be adjusted via the nature and / or amount of the solvent in which the one or more curable compounds are formulated.

[0062] Thus, the one or more curable compounds may have a viscosity, measured at ambient temperature and pressure, of 30 mPa.s to 40 Pa.s, in particular 50 mPa.s to 20 Pa.s.

[0063] The viscosity of the composition may be measured by conventional methods. The selection of an appropriate method and measuring instrument for the measurement, particularly with respect to the magnitude of the viscosity of the composition in question, is clearly within the capabilities of a person skilled in the art.

[0064] The varnish in its hardened form can be completely transparent. This pseudo-invisibility of the applied varnish is particularly advantageous for obvious reasons. In particular, the varnish according to the invention has proven to be particularly advantageous for constituting an overprint varnish for information carriers, such as banknotes. The varnish according to the invention does not impair the visibility of security elements incorporated in these banknotes.

[0065] The varnish according to the invention may contain between 0.001% and 0.2% by weight, preferably between 0.003% and 0.015%, more preferably less than 0.01% or even less than 0.008% of metals in an oxidation state equal to zero, relative to its total weight.

[0066] The varnish according to the present invention contains at least some iodopropynyl butylcarbamate, or IPBC.

[0067] As an illustration of IPBC, we may mention, for example, the product sold by the company Troy Chemical Company under the name Fungitrol C450.

[0068] In particular, the varnish according to the invention may contain 0.1% to 5.0% by weight, preferably 1% to 4% by weight, more preferably 1.5% to 3.5% by weight of IPBC relative to its total weight.

[0069] Advantageously, the metal in the zero oxidation state and the IPBC are used in a metal / IPBC weight ratio of 0.0007 to 0.01, preferably 0.0008 to 0.007, preferably 0.001 to 0.005, more preferably 0.0015 to 0.004, or even 0.0017 to 0.0034.

[0070] In addition to the supported zero metal and the IPBC, the varnish may advantageously contain a supplemental antimicrobial agent, provided that the supplemental antimicrobial agent is compatible with formulation in non-aqueous media and irradiation, particularly UV.

[0071] Advantageously, the varnish according to the invention additionally comprises at least one biocide different from IPBC.

[0072] According to one variant, the composition according to the invention comprises at least one bacteriostatic and / or bactericidal agent chosen from isothiazolin- or isothiazolin-derivative-based compounds, zeolite-based compounds, zinc-based compounds and triclosan-based compounds.

[0073] Preferably, the varnish according to the invention comprises as bacteriostatic and / or bactericidal agent at least one compound selected from p-((diiodomethyl)sulfonyl)toluene and methyl-1H-benzimidazol-2-ylcarbamate.

[0074] The varnish according to the invention may contain from 0.1% to 2.0% by weight, preferably from 0.5% to 1.5% by weight, of one or more fungicides relative to its total weight. Advantageously, the varnish according to the invention may contain from 0.1% to 5.0% by weight, preferably from 1% to 4% by weight, more preferably from 1.5% to 3.5% by weight, of one or more fungicides relative to its total weight.

[0075] Security Documents As mentioned above, the varnish according to the invention is very particularly suitable for forming protective coatings, in particular antimicrobial coatings, on the surfaces of security documents intended to be handled relatively frequently.

[0076] In the sense of the present invention, a "security document intended to be handled relatively frequently" is a substrate that is manually handled at least twice, by the same individual or by at least two different individuals. The manual handling may consist of at least one contact, for example, grasping with at least part of one hand. Furthermore, the security documents considered according to the present invention are intended for use in ambient atmosphere and not for use in liquid media.

[0077] Security documents according to the invention which are intended to be handled relatively frequently may in particular be based on papermaking fibres known by those skilled in the art, such as cellulose fibres (in particular cotton fibres) and / or natural organic fibres other than cellulose fibres, and / or synthetic fibres, such as polyester fibres or polyamide fibres, and / or optionally mineral fibres, such as glass fibres.

[0078] According to one embodiment, the security document is based on a material, in particular cellulose fibres, in particular paper.

[0079] According to another embodiment, the security document is based on natural organic fibers other than cellulosic.

[0080] According to yet another embodiment, the security document is based on a plastic material, in particular a synthetic fiber or a plastic sheet.

[0081] The security document can also be a plastic film, in particular a biaxially oriented film based on polyethylene or polypropylene. The security document can be, for example, a saturated polyester, such as poly(ethylene terephthalate). The security document can also be a polycarbonate or polyvinyl chloride (PVC) film.

[0082] The security document may also be multi-layered, in particular laminated or laminated multi-layered.

[0083] According to a preferred embodiment, the security document according to the invention incorporates at least one security element allowing authentication of said sheet.

[0084] In particular, the security elements are selected from optical devices, in particular optically variable devices known as OVDs, holograms, lenticular devices, elements with interference effects, in particular iridescent elements, liquid crystals, magnetically orientable effect pigments and multilayer interference structures. These optically variable devices may be present on a security thread incorporated in the document or on a strip or patch attached or printed on the document.

[0085] As another visual security element, we may also refer to watermarks that are produced during the banknote manufacturing process.

[0086] In particular, said security elements may be chosen from so-called luminescent elements detectable under UV or IR, these luminescent elements being in the form of particles, fibrettes, tags, security threads in strips or patches attached or printed on the security document.

[0087] In particular, said security elements may be selected from automatically, in particular optically or magnetically, detectable elements, commonly called markers or taggants, which are incorporated into the textile substrate or into visual or luminescent security elements.

[0088] The security document according to the invention may also include a radio frequency identification device, called RFID, which provides identification and traceability functions to the security sheet.

[0089] Thus, the security document according to the invention may be a passport, a banknote, an identity card, a driver's license, an access card, a loyalty card, a photocopying card, a canteen card, a playing card, a collection card, a payment instrument, in particular a payment card.

[0090] Advantageously, the security document considered according to the invention is a security sheet, in particular a printed security sheet, which incorporates at least one security element allowing authentication of the sheet, and which security document is preferably a banknote.

[0091] The security document according to the invention has one or more outer surfaces that are coated, in whole or in part, with a hardened varnish deposit formed from a curable varnish according to the invention.

[0092] In particular, the security document may contain, relative to its total weight, from 0.25 ppm to 3.1 ppm of metals originating from metals in the zero oxidation state present in the varnish.The security document may also contain, relative to its total weight, from 100 ppm to 1200 ppm of IPBC.

[0093] More particularly, the security document according to the invention is surface treated, on at least one of its one or more faces, with a cured varnish film formed from a curable varnish according to the invention.

[0094] For this purpose, the security document surface is contacted with a curable varnish according to the invention under conditions effective to form a deposit of curable varnish, preferably in the form of a film, and the deposit thus formed is exposed to radiation to cure said varnish.

[0095] The contact of the varnish with the surface of the document to be treated indicates that the varnish has been deposited on at least part of the surface of the document to be treated. The formation of this deposit of varnish is carried out according to the usual conditions. As examples of possible deposition techniques, we may mention in particular printing processes, in particular flexographic, gravure or serigraphic, by spraying, by application by brush or by any other coating process.

[0096] The varnish is cured by drying the curable varnish.

[0097] This drying can be carried out by exposure to infrared or UV radiation using suitable lamps.

[0098] The deposit is about 0.5 to about 5 g / m 2 , especially 1.5 to 2.5 g / m 2 , or even about 1.5 to about 2 g / m 2 , can be formed by application of a curable varnish.

[0099] As will become apparent from one or more of the examples given below, the varnish film advantageously makes it possible to impart antibacterial, antifungal and antiviral properties to the corresponding security document without altering the appearance of the varnish film or its durability-enhancing properties.

[0100] Antimicrobial activity may be assessed, inter alia, by testing for antifungal, antiyeast, antibacterial and antiviral properties, as detailed in the section entitled Materials and Methods below.

[0101] Banknotes coated with a cured varnish derived from a curable varnish according to the present invention therefore have enhanced resistance to soiling compared to the resistance to soiling of untreated banknotes.

[0102] The use of a varnish according to the invention makes it possible to improve the barrier properties, including quite particularly the resistance to soiling, of security documents, in particular banknotes, i.e. the use may in particular prevent or reduce the formation and / or accumulation of stains.

[0103] The barrier properties, including very particularly resistance to fouling, can be assessed by the Cobb, Fritsch and Kit tests detailed in the Materials and Methods section.

[0104] One or more examples and figures provided below are presented for illustrative purposes and do not limit the scope of the present invention.

[0105] Materials and Methods The information carrier is a cotton-fiber-based paper substrate for banknotes (= "vellum").

[0106] Varnishing Operation The varnishing operation is carried out in Rect / Verso (R° / V°) on a vellum substrate (100% cotton) glazed on one side (i.e. provided by an inkless dry stamp produced by a copperplate printing process) on a Group 1 flexographic press equipped with an in-line UV drying unit. 6 cm unless otherwise stated. 3 / m 2 A flexographic printing plate having an anilox value of 0.01 mm and a solid tone is used for flexographic printing.

[0107] The anilox value corresponds to the surface volume of ink or varnish that a flexographic printing cylinder, called an "anilox cylinder," can transfer to the flexographic printing plate.

[0108] Testing for antifungal properties The antifungal properties are characterized by fungistatic control according to textile standard AATCC-30 test 3 using Aspergillus niger van Thiegem (DSM 1957) and according to standard AFNOR NFX41517 using a mixture of 10 strains and a contact time of 7 and / or 14 days.

[0109] Testing for anti-yeast properties The anti-yeast properties are characterized by control according to standard NF ISO 13629-2:2014 using Candida albicans ATCC 10231.

[0110] Testing for antibacterial properties The antibacterial properties are characterized by antibacterial control according to the standard NF EN ISO 20743:2013 - Determination of the antibacterial activity of textiles and textile products, transfer method, using the Escherichia coli (ATCC 8739) strain, representing a gram-negative bacterium, and the Staphylococcus aureus (ATCC 6538) strain, representing a gram-positive bacterium.

[0111] Testing for antiviral properties Unless otherwise stated, the antiviral properties are characterized by antiviral control according to standard ASTM 1053-97 with a contact time of 5 hours using the coronavirus OC43 (ATCC VR-1558) strain.

[0112] Other viral strains, especially influenza A H1N1 (ATCC VR1469) or coronavirus HcoV-229 E , can be used.

[0113] Tests to evaluate barrier properties The barrier properties are characterized by three tests described below.

[0114] Cobb : The Cobb test, carried out according to the standard ISO 535:2014, makes it possible to characterize the water resistance of the samples.

[0115] Fritsch The resistance to soiling was tested according to the so-called "dry soil" test (Fritsch test). It is a vibrating device ("Analysette 3 Pro" from the Fritsch company) in which small glass beads spread and sprinkle a soiling composition based on sand, peat, activated carbon, wheat flour, and glycerin monooleate (a fat present in sebum) onto a paper test piece. The test takes 15 minutes. The brightness of the zones, notably the unprinted zones, determined at the start, is measured several times before and after exposure to the soiling composition. The difference obtained, i.e., ΔL*, makes it possible to characterize the adhesion of the soil to the banknote: the lower the value, the better the resistance to dry soiling.

[0116] Test kit : The test kit, prepared according to standard TAPPI T559 CM-12, makes it possible to evaluate the oil resistance of the samples.

[0117] Testing print reproductions containing gloss The gloss is measured at an angle of 60° according to standard ISO 2813.

[0118] Color rendering test The colour (L*, a* and b*) is measured according to standard NF EN ISO / CIE 11664-4 using a D65 illuminant and an angle of 10°.

[0119] Example 1 A composition of cationic UV varnish (viscosity of about 60 seconds DIN 4) is prepared from 99.7% of the standard cationic UV varnish sold under the reference number 889 368 by the company Sicpa (hereinafter "Varnish V1") and 0.3% of Ultrafresh CA16 from the company Thomson Research Associates Inc.

[0120] The composition is tested on a vellum-type substrate, laminated on one side (=TD 1 side).

[0121] Polished surface = Recto (R°) and unpolished surface = Verso (V°).

[0122] For comparison purposes, varnish V1 (100%) is also tested.

[0123] Two varnishes, 6cm 3 / m 2 It is applied by an anilox.

[0124] The formed coating(s) are tested for their resistance to water, dirt, and oil according to the protocols described in the Materials and Methods section.

[0125] The results are shown in Table 1 below.

[0126] [Table 1]

[0127] These results show that adding a biocide advantageously does not have a significant effect on the water, stain and oil resistance properties.

[0128] Example 2 Preparation of a composition according to the present invention additionally incorporating Fungitrol Varnish with the following formulation 98.7% Varnish V1 1% Fungitrol C450 (iodide propynyl butylcarbamate, or IPBC) 0.3% Ultrafresh CA16 are prepared according to the protocol detailed below.

[0129] For 1 kg of final product: In a beaker, in a fume hood, incorporate 10 g of Fungitrol C450 into 987 g of varnish V1. Using a laboratory disperser (e.g., a disperser manufactured by Dispermill, model Vango 100) with a dispersing disc suitable for the size of the beaker used, mix the whole at a speed of 1000 rpm for 15 minutes. Next, incorporate 3 g of Ultrafresh CA 16 into this mixture, and mix the whole again with the disperser under the same conditions as Fungitrol (1000 rpm - 15 minutes). The varnish thus obtained is left to stand until the air bubbles disappear before use.

[0130] Example 3 Application of the composition according to Example 2 and characterization of the biocidal and barrier properties, including resistance to fouling, of the resulting varnish The varnishes under consideration (the varnish according to the invention from Example 2 and the control varnish without Fungitrol or Ultrafresh) were 6 cm 3 / m 2 Anilox of 1000 rpm is used to apply the coating onto the same substrate as in Example 1.

[0131] Tables 2 and 3 below report the antifungal properties tested according to the protocol detailed in the Materials and Methods section. Four measurements are performed on each side of the sample (recto and verso), i.e., eight measurements per sample.

[0132] One or more boxes are read as follows: 0: No occurrence 1: Traces of fungal growth 2: Slight occurrence (10-30% of the surface of the test piece) 3: Moderate occurrence (30-60% of the specimen surface) 4: Strength development (>60% of the specimen surface)

[0133] [Table 2]

[0134] It can thus be seen that the control varnish does not provide antifungal protection and that, on the contrary, the varnish according to the invention is indeed antifungal. The fungicide therefore maintains its activity in the proposed formulation.

[0135] [Table 3]

[0136] This test confirms that the control varnish does not provide antifungal properties. The varnish according to the invention gives good results after 7 days, with only traces of fungal development. After 14 days, the results are still improved compared to the control varnish.

[0137] Table 4 below presents the antibacterial properties tested according to the protocol detailed in the Materials and Methods section.

[0138] [Table 4]

[0139] It can be seen that only the substrates with the varnish according to the invention exhibit significant bactericidal activity. In fact, the unvarnished substrates offer no or little protection, while the control varnished substrates offer only moderate bacteriostatic protection. The treatment therefore makes it possible to provide effective antibacterial protection.

[0140] Table 5 below reports on the barrier properties, including resistance to fouling, of the varnishes according to the invention compared to the control varnish.

[0141] The barrier properties are tested according to the protocol detailed in the Materials and Methods section.

[0142] [Table 5]

[0143] The properties of the varnish (resistance to water, dirt and oil) are not deteriorated by the addition of Fungitrol and Ultrafresh.In fact, the results for the varnish according to the invention are comparable to or even slightly better than those for the control varnish.

[0144] The following measurements were also carried out to verify that the varnish according to the invention does not alter the print reproduction of the banknote (and consequently the varnished banknote), including the gloss of the varnish.

[0145] The results of the gloss measurements are shown in Table 6 below.

[0146] [Table 6]

[0147] The differences between the control varnish and the varnish according to the invention are small and not significant in terms of the standard deviation. The treatment therefore also has the advantage of not affecting the gloss.

[0148] The following measurements were also carried out to verify that the varnish according to the invention does not alter the color rendering, and the results are shown in Table 7 below.

[0149] [Table 7]

[0150] The color change associated with banknotes with varnish V1 is very slight with the varnish according to the invention and is not significant in terms of the standard deviation. Therefore, the treatment also has the advantage of not affecting the color.

[0151] Example 4 Preparation of compositions according to the invention Varnish with the following formula: F1 97.7% Varnish V1 2% Fungitrol C450 0.3% Ultrafresh CA16 is prepared according to the protocol detailed in Example 2, in which 20 g of Fungitrol C450 are incorporated into 977 g of varnish V1.

[0152] Example 5: Application of the composition according to Example 4 and characterization of the biocidal and barrier properties, including resistance to fouling, of the resulting varnish The varnishes under consideration (varnish F1 according to the invention and the control varnish from Example 4) were 6 cm 3 / m 2 Anilox of 1000 rpm is used to apply the coating onto the same substrate as in Example 1.

[0153] Tables 8 and 9 below report the antifungal properties tested as in Example 3, following the protocol detailed in the Materials and Methods section.

[0154] [Table 8]

[0155] As in Example 3, the control varnish does not provide antifungal protection, contrary to the varnish according to the invention. It can be seen that increasing the amount of IPBC increases the size of the zone of inhibition.

[0156] [Table 9]

[0157] Compared to Example 3, the results for this varnish F1 are clearly improved compared to the varnishes with a lower IPBC content, with no fungal growth at any of the measurement points after 7 days and at 6 out of 8 measurement points after 14 days.

[0158] Table 10 below reports on the anti-yeast properties:

[0159] [Table 10]

[0160] The varnish according to the invention endows the sample with yeast-killing properties with 100% mortality after 24 hours.

[0161] Table 11 below reports on the antibacterial properties tested according to the protocol detailed in the Materials and Methods section.

[0162] [Table 11]

[0163] It can be seen that the substrates provided with the varnish according to the invention exhibit a significant bactericidal activity, and therefore the treatment makes it possible to provide effective antibacterial protection.

[0164] Table 12 below reports on the antiviral properties of the varnish according to the invention and of the control varnish, compared to an untreated sample of varnish shown as a reference in the table.

[0165] The percentage decrease from time T0 to time T5 corresponds to the percentage decrease in the viral load after 5 hours of contact.

[0166] The "Antiviral activity vs. reference" row corresponds to the logarithmic reduction in viral load between times T0 and T5 of the samples studied compared to the reference.

[0167] Antiviral properties are tested according to the protocol detailed in the Materials and Methods section.

[0168] [Table 12]

[0169] The varnish according to the invention has an activity that can be considered as virucidal, with a reduction rate nearly equal to 100%. The gain compared to the control varnish is significant, with a reduction in the viral load 220 times greater.

[0170] Table 13 below reports on the barrier properties, including resistance to soiling, of the varnishes according to the invention compared to the control varnish.

[0171] The barrier properties are tested according to the protocol detailed in the Materials and Methods section.

[0172] [Table 13]

[0173] The properties of the varnish (resistance to water, dirt and oil) are not deteriorated by adding Fungitrol and Ultrafresh. In fact, the results for the varnish according to the invention are very close to those for the control varnish. The small differences observed are not significant in terms of the standard deviation.

[0174] Example 6 Various formulations of varnish detailed below in Table 14 are prepared according to the protocol described in Example 2. The contents are expressed as weight percent in the varnish.

[0175] The varnishes under consideration are applied onto the same substrates as in Example 1 according to the varnish treatment protocol detailed in the Materials and Methods section.

[0176] The antiviral activity was tested according to the protocol detailed in the Materials and Methods section and is reported below in Table 14. Results for Varnish F1, detailed in Example 5, are also included for comparison.

[0177] [Table 14]

[0178] Thus, it can be seen that varnishes F1 and F4, which contain both silver in the zero oxidation state and IPBC in supported form, exhibit greater antiviral activity than the control varnish, and also greater antiviral activity than varnish F5, which lacks silver in said supported form.

[0179] Example 7 Various varnish formulations detailed in Table 15 below were prepared according to the protocol described in Example 2. Contents are expressed as weight percent in the varnish.

[0180] The information carrier is also a cotton fiber based banknote paper substrate, related to the paper substrate used for one or more of the preceding embodiments.

[0181] The varnishes under consideration were applied to this substrate in a 7 cm thickness according to the varnish treatment protocol detailed in the Materials and Methods section. 3 / m 2 It is applied by an anilox.

[0182] The antiviral activity is then tested according to the protocol detailed in the Materials and Methods section.

[0183] [Table 15]

[0184] A comparison of Varnish F1 and Varnish F2 shows that the virus reduction and the antiviral activity decrease when the content of silver deposited in the varnish, and therefore also on the substrate, increases.

[0185] Example 8: Application of the composition according to Example 4 onto a plastic substrate and characterization of the biocidal properties of the varnish formed Varnish F1' is prepared in the same way as varnish F1 described in Example 4, according to the protocol described in Example 2, with varnish V1 being replaced by the varnish commercialized by the company Sicpa under the reference number 889 354 (hereinafter "varnish V1'"). The contents are expressed as percentages by weight in the varnish.

[0186] The information carrier is the "Guardian" plastic substrate for banknotes, sold by the company CCL Secure.

[0187] The antiviral activity shown in Table 16 below is characterized by the antiviral control according to the standard ISO 21702:2019 (Determination of antiviral activity on plastic and other non-porous surfaces).

[0188] [Table 16]

[0189] Considering the results, the antiviral protection of varnish F1 is confirmed on plastic substrates.

Claims

1. 1. A protective varnish curable by radiation, comprising: at least one compound curable by cationic or radical means; at least one fungicide comprising at least iodopropynyl butylcarbamate, or IPBC; at least one metal selected from silver, copper, zinc, and mixtures thereof; Including, The protective varnish, wherein the metal is in the zero oxidation state and in supported particulate form.

2. 2. The varnish according to claim 1, which has biocidal activity, in particular bactericidal, bacteriostatic and / or antiviral activity, preferably bactericidal and antiviral activity.

3. 3. A varnish according to claim 1 or 2, wherein the metal in the zero oxidation state is supported by inorganic particulate matter.

4. 4. A varnish according to claim 3, wherein the loading of the material with metals in the zero oxidation state varies between 0.5% and 3% by weight, in particular between 1.0% and 2.5% by weight, relative to its total loading weight.

5. 5. A varnish according to claim 3 or 4, wherein the particle size of the zero metal loaded or doped material is preferably less than 10 μm, preferably less than 5 μm.

6. 6. A varnish according to any one of claims 3 to 5, wherein the inorganic material is selected from zeolites and glasses, in particular phosphate glasses, preferably phosphate glasses.

7. A varnish according to any one of claims 1 to 6, wherein said metal in zero oxidation state is selected from zinc, silver, copper and mixtures thereof, preferably comprising at least silver.

8. 8. A varnish according to any one of claims 1 to 7, comprising between 0.001% and 0.2% by weight, preferably between 0.003% and 0.015%, more preferably less than 0.01% or even less than 0.008% of metals in an oxidation state equal to zero, relative to the total weight of the varnish.

9. A varnish according to any one of claims 1 to 8, characterized in that it is a varnish curable by UV-visible radiation, preferably a cationic varnish.

10. 10. The varnish according to claim 1, which is a varnish based on monomers of polyalkyl acrylates, an unsaturated acrylic resin, or a varnish based on monomers of cycloaliphatic epoxides.

11. A varnish according to any one of claims 1 to 10, further comprising a free radical photoinitiator.

12. 12. A varnish according to any one of the preceding claims, comprising 0.1 to 5.0% by weight of IPBC, preferably 1 to 4% by weight, more preferably 1.5 to 3.5% by weight, relative to the total weight of the varnish.

13. 13. A varnish according to any one of claims 1 to 12, wherein the metal in the zero oxidation state and the IPBC are used in a metal / IPBC weight ratio of 0.0007 to 0.01, preferably 0.0008 to 0.007, preferably 0.001 to 0.005, more preferably 0.0015 to 0.004, or even 0.0017 to 0.0034.

14. 14. The varnish according to claim 1, further comprising at least one bactericide different from IPBC, said bactericide being selected from isothiazolin or isothiazolin derivative-based compounds, zeolite-based compounds, zinc-based compounds and triclosan-based compounds, in particular at least one compound selected from p-((diiodomethyl)sulfonyl)toluene and methyl-1H-benzimidazol-2-ylcarbamate.

15. A varnish according to any one of claims 1 to 14, characterized in that it is an overprint varnish.

16. An object having one or more outer surfaces thereof coated, in whole or in part, with a cured varnish deposit formed from a curable varnish according to any one of claims 1 to 15.

17. 17. The object according to claim 16, wherein the object is intended to be touched or handled, and is in particular selected from a handle, a button, a touch screen, packaging, and an information carrier.

18. A method for producing an object, in particular an object according to any one of claims 16 to 17, comprising the steps of: providing said object; contacting the surface of the object to be treated with a varnish according to any one of claims 1 to 15 under conditions effective to form a hardenable varnish deposit on said surface; and exposing the deposit to radiation to harden the deposit; The method, comprising at least the steps of:

19. A security document having one or more outer surfaces thereof coated, in whole or in part, with a hardened varnish deposit formed from a curable varnish according to any one of claims 1 to 15.

20. 20. A security document according to claim 19, wherein the security document is based on cellulose fibres, in particular paper.

21. 20. A security document according to claim 19, wherein the security document is based on a plastic material, in particular on synthetic fibres or plastic sheets.

22. 22. A security document according to any one of claims 19 to 21, wherein the security document is a passport, a banknote, an identity card, a driver's license, an access card, a loyalty card, a copy card, a restaurant card, a game card, a collection card, a payment instrument, in particular a payment card.

23. A security document according to any one of claims 19 to 22, in the form of a security sheet, preferably a banknote, incorporating at least one security element allowing authentication of the sheet.

24. 1. A method for producing a security document, comprising: providing said security document; contacting the surface of the document to be treated with a varnish according to any one of claims 1 to 15 under conditions effective to form a hardenable varnish deposit on said surface; and exposing the deposit to radiation to harden the deposit; The method, comprising at least the steps of:

25. Use of a varnish according to any one of claims 1 to 15 for producing a protective coating or layer on a security document, preferably a banknote.

26. Use of a varnish according to any one of claims 1 to 15 for improving the resistance to fouling of security documents, preferably banknotes.

27. Use of a varnish according to any one of claims 1 to 15 for imparting antimicrobial properties to security documents, preferably banknotes.

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