TOUCHSCREEN SECURITY FEATURE FOR BANKNOTES AND BANKNOTES

Abstract

The present invention relates to a tactile security feature for a banknote having a printed marking layer comprising a design element and a printed enhanced tactile layer, which has at least one first enhanced tactile zone overlapping the design element, such that the design element appears to have a certain tactile quality due to the overlap of the first enhanced tactile zone, the design element and the first enhanced tactile zone together forming the security feature. FIG. 4C

Description

Title of the invention: TOUCHSCREEN SECURITY FEATURE FOR TICKET BANK AND BANKNOTE technical field

[0001] The present invention relates generally to a banknote, a method for producing a banknote, a coating for a banknote and a security feature for a banknote. State of the art

[0002] Nowadays, banknotes are produced using sequential printing processes involving different printing technologies. More specifically, a banknote substrate undergoes several different types of printing processes in series, each of which is fully completed before the next step is applied, resulting in significant overhead costs in terms of handling and storage. The majority of banknotes worldwide are printed using sheet-fed systems, meaning that the substrate is cut into sheets of a specified size and each sheet is printed sequentially. The nature of the printing processes used is such that a period of time is required between each of the different printing steps. This waiting time between steps is due to the inks used in the individual processes.Although some processes use inks that are cured using actinic radiation, most are based on oxidative systems that require a certain amount of time before the inks are sufficiently polymerized to be usable and robust enough to allow the production of a banknote. This is particularly true when intaglio printing is used to create tactile designs. Intaglio printing processes for banknote production deliver print heights of 20 to 60 microns or more, and the sheets must be allowed to dry without being stacked, which would risk flattening the ink.

[0003] The typical process is as described below:

[0004] a. Offset printing (wet or dry) to create the background designs

[0005] b. Intaglio printing for the main imagery / portrait of the banknote

[0006] c. Numbering (letterpress printing)

[0007] d. Recovery

[0008] e. Inspection

[0009] f. Cutting / trimming.

[0010] There may be additional steps, in that additional security features may be added using distinct and separate processes, such as screen printing or hot stamping. Each of the above steps requires a separate process with dedicated equipment, personnel, additional time management, skills, and ink / application chemical composition.

[0011] There have been attempts to combine these processes into one, such as Goebel's Intaglio press and web offset printing, as well as the SNOW ("Single Note on Web") concept. Both of these systems attempt to carry out the various process steps mentioned above in a single online system. More specifically, each different type of printing process is placed in a separate online system. Technical, quality, and cost problems have prevented the success of these processes.

[0012] Moreover, each of these process steps adds considerable cost and time to the production of a banknote. The time component can be a month or more, meaning that a process must be maintained for a month, with personnel costs requiring at least two, or normally three or more, dedicated operators per process, as well as security costs for managing and storing the required volume of materials. All of this adds to the already excessive cost and time involved in producing a banknote. In some cases, these costs may exceed the value of the banknote itself.

[0013] It is also necessary that each individual process be recorded with the preceding process. The very nature of the sheet feeding processes results in variation not only in the sheet placement during the different processes, but also in the mounting of the various blankets, plates, and similar equipment. This therefore requires that the customer and the banknote designer tolerate lower levels of precision than they would like between the substrate, the security features, and the security printing. These tolerances can be as low as 1.4 mm. Cutting processes used during substrate manufacturing further exacerbate this to the point that the sheets may be cut at an angle to the design, which further increases the need for even greater adaptation of the design downstream, at the expense of the document's security.Variations in tolerances compromise the security of banknotes because a counterfeiter can exploit this problem to produce low-quality replicas of the original documents.

[0014] Banknotes currently available on the market are formed using starting materials consisting of the following:

[0015] a. The production of a fibrous material to produce a porous, substantially opaque substrate (paper or similar materials) to DuPont's Tyvek®, which was used unsuccessfully on banknotes in the 1980s).

[0016] b. The extrusion-lamination of one or more sheets of fibrous material onto one or more clear polymer layers. An opening may be pre-prepared in the fibrous layers during the process to create a transparent region or window (Durasafe® Landqart - US20060198987A1).

[0017] c. Laminating one or more polymer layers onto a fibrous layer (paper), then optionally cutting openings in the paper before or after lamination to create a transparent area. This process may have one or more layers of opacifying ink coatings added to the surface of the polymer layers to create an ink-receiving layer (Hybrid™ Giesecke and Devrient).

[0018] d. A transparent polymer substrate that is selectively opacified by the application of one or more layers of opacifying ink (Guardian "CCL Secure, formerly Innovia Security, formerly Securency).

[0019] All the above elements are produced, cut into sheets, and then brought into the various printing processes described above (Offset, Intaglio, numbering, etc.).

[0020] All banknotes currently available commercially are formed using starting materials consisting of the following:

[0021] a. Banknotes are produced using a chemical composition of marking inks based on a number of systems, but the majority of these are based on air-oxidation inks. More specifically, oil-based inks that oxidize in the presence of air and metallic soaps to form cross-linked structures. There is an increasing use of actinic radiation-cured inks.

[0022] b. The inks used for polymer and hybrid structures are of a different chemical composition and usually involve crosslinking using a range of chemical curing compositions, usually resulting in a high molecular weight, highly crosslinked polymer system.

[0023] c. There is usually a considerable time lag (more than one day and usually at least three days) between the time a substrate is produced and the time it is printed. This is partly due to the need to cure and / or coalesce the substrate coatings.

[0024] d. Meanwhile, not only does the material's surface increase the molecular weight, but it can also reduce the surface energy value. These are desirable properties from the point of view of surface robustness.

[0025] e. This process, however, reduces the ability of the inks applied to the surface to penetrate the surface and achieve total adhesion.

[0026] f. The disparate nature of the inks applied to the surface in the form of a printed marking further reduces the adhesion between the surface of the material and the marking inks.

[0027] g. The relatively low molecular weight of the crosslinked marking ink system compared to the surface ink results in the marking ink being softer than surface materials and therefore more prone to wear than surface materials in the same environment.

[0028] h. To overcome this problem, banknotes are increasingly coated with a one- or two-layer coating system per surface after printing, in order to prevent the marking from wearing off too quickly. This process is expensive to carry out and does not solve the problem but tends to minimize it. A hard coating over a relatively softer coating will stop some types of wear but will not resolve all wear situations.

[0029] The above presents disadvantages in terms of cost, process, or material properties (opacity, durability), or a combination of some or all of these disadvantages. This situation is compounded by the fact that the banknote must then undergo a complete set of separate steps to become a final security document.

[0030] Although some prior art descriptions refer to the option of printing security documents, including banknotes, in a web-fed / roll-fed system, none of the prior art descriptions specifies how to implement such a system. For example, US Patent 4,536,016 A, column 4, lines 21-26, states that the substrate according to this description can be printed by normal high-quality presses for the production of banknotes and that these presses could be sheet-fed or web-fed presses. This description is already a multi-step process but gives no indication of how to obtain banknotes in a web-fed press.It is also common to produce individual security features in a reel-fed process and, in fact, to produce a suitable substrate for polymer banknotes, such as a Guardian® substrate. However, the challenges of producing a suitable banknote from reels are not addressed by any of the previous techniques, nor are there any solutions to the challenges described. Furthermore, banknote improvements can be achieved using a reel-fed system, which is also not addressed by the previous technique. Presentation of the invention

[0031] The present invention aims to remedy, improve or provide an alternative to banknotes, banknote production processes and / or banknote security features of the prior art.

[0032] According to a first aspect of the present invention, a method for producing a plurality of banknotes is made available comprising: bringing a substrate, in the form of a strip, to a printing press comprising a plurality of printing units of the same type of printing process, in which the strip will pass through each of the plurality of printing units, and at least a part of the strip is printed in a printing pass; printing a printing layer on the substrate at each of the plurality of printing units, at least one of the printing layers being a marking layer and at least one of the printing layers being a tactile layer.

[0033] According to a second aspect of the present invention, a method for producing a plurality of banknotes is made available, including:

[0034] the delivery of a substrate, in the form of a strip, to a printing press including a plurality of printing units of the same type of printing process,

[0035] the passage of the tape through at least two of the plurality of printing units, and at least a part of the tape is printed in one printing pass;

[0036] the printing pass comprising printing a printing layer onto the substrate with at least two of the plurality of printing units,

[0037] at least one of the printing layers being a marking layer and at least one of the printing layers being a tactile layer.

[0038] The first and second aspects of the present invention have the particular advantages that banknotes can be produced: in a single process; faster than with current processes; and / or at a lower cost than current processes, while also retaining the security features of comparative banknotes of the prior art.

[0039] The first and / or second aspects of the present invention provide banknotes that can be printed, on at least one side, in a single step. This process accelerates manufacturing and improves recording accuracy through the creation of marking and tactile elements in a continuous web-based printing process.

[0040] The following embodiments may be applied to the first and / or second aspects of the invention.

[0041] In one embodiment, the substrate comprises a polymer material. A suitable polymer material includes, but is not limited to, polypropylene. (PP), polyethylene (PE), polycarbonate (PC), polyvinyl chloride (PVC), poly(ethylene terephthalate) (PET), biaxially oriented polypropylene (BOPP); or a composite material of two or more of these materials.

[0042] In one embodiment, the tactile layer is a paper-like touch layer printed on the substrate, which provides a sensation substantially similar to that of a paper banknote. In another embodiment, the tactile layer is a transparent or translucent paper-like touch layer.

[0043] A tactile layer such as this has the advantage of offering greater public acceptability, because it offers a feel more similar to traditional banknotes, and it also reduces the tendency of polymer banknotes to stick together.

[0044] In one embodiment, the paper-touch layer includes an ink having tactile particles. In one embodiment, the tactile particles have an average particle size of 5 to 35 microns in at least one dimension. In one embodiment, the tactile particles have an average particle size aspect ratio of between approximately 1 and 5.

[0045] In one embodiment, the paper-touch layer contains approximately 5% to 20% by weight of tactile particles relative to the ink, preferably approximately 10% to 15%. In one embodiment, the tactile particles consist of one or a combination of polyethylene, polypropylene, glass, acrylic, polyurethane, ceramic, or rubber.

[0046] In the context of this description, weight percentages are given for "wet" inks, before curing processes, such as those which can evaporate elements of the ink, such as solvents.

[0047] In one embodiment, the paper-touch layer has an average particle depth to binder depth ratio in the range of 3:1 to 7:1. In one embodiment, the paper-touch layer is applied in a first thickness in first regions and a second thickness in second regions, the second regions offering improved tactility.

[0048] In one embodiment, the paper-touch layer is conductive. In another embodiment, the tactile particles are conductive. In yet another embodiment, the paper-touch layer includes conductive particles in addition to the tactile particles.

[0049] In one embodiment, the quantity of conductive particles is appropriately determined so that the paper-touching layer has a surface resistivity of less than 1011 Ohms per square.

[0050] In one embodiment, the conductive particles are a fibrous conductive filler material which is a fibrous core material on which is formed a conductive layer, the conductive particles preferably containing at least one tin oxide and one antimony oxide.

[0051] In one embodiment, the fibrous conductive filler material particles have an average length of 3 to 50 microns, preferably the fibrous conductive filler material particles have an average diameter of 0.01 to 5 microns, and preferably still, the fibrous conductive filler material particles have an average aspect ratio of 3 to 100.

[0052] In one embodiment, the conductive particles are provided in the paper-touching layer at a concentration of approximately 10% to 15% by weight.

[0053] In one embodiment, the marking layer, or an additional marking layer, includes a drawing element, and the tactile layer, or an additional tactile layer, is an enhanced tactile layer, or includes enhanced tactile regions, having at least one first enhanced tactile area imprinted substantially on the drawing element, such that the drawing element appears to have a certain tactile quality due to the first enhanced tactile area, the drawing element and the first enhanced tactile area together forming a security feature. In this embodiment, the enhanced tactile layer may be substantially transparent or translucent.

[0054] In one embodiment, the first enhanced tactility zone has ends that are not substantially larger than the ends of the drawing element.

[0055] In one embodiment, the first enhanced touch area comprises a pattern of enhanced touch sub-areas, the sub-areas preferably being lines and / or dots.

[0056] In one embodiment, the enhanced tactile layer contains tactile particles, the tactile particles preferably having a dimension which has an average size of 5 to 70 microns, or, in another embodiment, of 10 to 70 microns.

[0057] In one embodiment, the tactile particles have an average diameter of approximately 20 microns and, preferably, are spherical. In another embodiment, the tactile particles have at least one dimension whose average size is at least 150% of the average size of the smallest dimension.

[0058] In one embodiment, the tactile particles are retroreflective, or semi-retroreflective.

[0059] In one embodiment, each of the printing layers printed by the plurality of printing units is printed with an ink having a Relative Energy Difference, relative to any other ink in the printing layers, less than or equal to one, or less than or equal to 0.5, for example less than or equal to 0.3.

[0060] In one embodiment, each of the inks has a "hydrogen bonding" parameter by Hansen solubility, θh, having a difference of less than 2.5 compared to any other ink in the printing layers.

[0061] In one embodiment, each printing layer is printed inline before the immediately preceding layer has completely hardened and / or coalesced, resulting in the effect that, where the printing layers overlap, the printing layers partially dissolve into one another.

[0062] In one embodiment, the printing press is an intaglio printing press. In one embodiment, each of the plurality of printing units is an intaglio printing unit.

[0063] In one embodiment, the printing press includes one or more additional printing units of a printing process different from the plurality of printing units, and the method further includes printing a printing layer onto the substrate at the additional printing units in the printing pass. In one embodiment, the method includes printing a different printing layer design on at least two of the plurality of banknotes, preferably on each of the plurality of banknotes, at each additional printing unit. In one embodiment, at least one additional printing unit is an inkjet printing unit. In one embodiment, the inkjet printing unit prints a unique image and / or text on each banknote.In one embodiment, the inkjet printing unit prints a unique serial number on each banknote.

[0064] In one embodiment, the substrate strip is treated so as to promote adhesion before printing, at least, a first printing layer.

[0065] In one embodiment, the treatment includes the application of a corona discharge.

[0066] In one embodiment or additional embodiment, the treatment is an impression of an adhesion-promoting layer.

[0067] In one embodiment, it is further included the step of inspecting the tape during the printing pass, including: taking an image of at least one of the printing layers; and quantifying the printing quality and / or registering the printing layer.

[0068] According to a third aspect of the present invention, a banknote produced by the first and / or second aspect of the present invention is made available. Embodiments of the third aspect of the invention may therefore include any of the embodiments of the first and second aspects of the invention.

[0069] According to a fourth aspect of the present invention, a banknote is made available having at least two marking layers or at least one marking layer and at least one tactile layer, each layer being printed with an ink having: a Relative Energy Difference, with respect to the inks of the other said layer(s), less than or equal to one, preferably less than or equal to 0.5, or preferably less than or equal to 0.3; and / or Hansen Solubility parameters in the following ranges: ôd - between 17 and 19, ôp - between 9 and 11, and ôh - between 5 and 7.

[0070] In one embodiment, each of the inks has a "hydrogen bonding" parameter by Hansen solubility, θh, having a difference of less than 2.5 compared to any other ink of said layers.

[0071] In one embodiment, each of said layers is printed inline before the immediately preceding layer has completely hardened and / or coalesced, so that, where the layers overlap, the layers partially dissolve into each other.

[0072] In one embodiment, the substrate is a polymer material. A suitable polymer material includes, but is not limited to, polypropylene (PP), polyethylene (PE), polycarbonate (PC), polyvinyl chloride (PVC), poly(ethylene terephthalate) (PET), biaxially oriented polypropylene (BOPP); or a composite material of two or more of these materials.

[0073] In one embodiment, the banknote includes a tactile feature in which the tactile layer is a paper-like touch layer printed on the banknote, which provides a feel substantially similar to that of a paper banknote. In one embodiment, the tactile layer is printed with an ink having a Relative Energy Difference, with respect to all other inks in the other printing layers, less than or equal to one, for example, less than or equal to 0.5, or less than or equal to 0.3.

[0074] In one embodiment, the paper-touch layer includes tactile particles, the tactile particles preferably having a depth of 5 to 35 microns and, even more preferably, the tactile particles having an aspect ratio between substantially 1 and 5.

[0075] In one embodiment, the paper-touch layer contains approximately 5% to 20% by weight of tactile particles relative to the transparent ink, preferably approximately 10% to 15%. In one embodiment, the tactile particles consist of one or a combination of polyethylene, polypropylene, glass, acrylic, polyurethane, ceramic, or rubber.

[0076] In one embodiment, the paper-touch layer has an average particle depth to binder depth ratio in the range of 3:1 to 7:1. In In one form of implementation, the paper-touch layer is applied in a first thickness in first regions and a second thickness in second regions, the second regions offering improved tactility.

[0077] In one embodiment, the paper-touch layer includes conductive particles.

[0078] In one embodiment, the quantity of conductive particles is appropriately determined so that the paper-touching layer has a surface resistivity of less than 1011 Ohms per square.

[0079] In one embodiment, the conductive particles are a fibrous conductive filler material which is a fibrous core material on which a conductive layer is formed, the conductive particles preferably containing at least one tin oxide and one antimony oxide.

[0080] In one embodiment, the fibrous conductive charge material particles have an average length of 3 to 50 microns, preferably the fibrous conductive charge material particles have an average diameter of 0.01 to 5 microns, and preferably still, the fibrous conductive charge material particles have an average aspect ratio of 3 to 100.

[0081] In one embodiment, the conductive particles are provided in the paper-touching layer at a concentration of approximately 10% to 15% by weight.

[0082] In one embodiment, the at least two printing layers include a marking layer and a tactile layer, and the marking layer, or an additional marking layer, includes a drawing element, and the tactile layer, or an additional tactile layer, is an enhanced tactile layer, or includes enhanced tactile regions, having at least one first enhanced tactile area printed substantially on the drawing element, such that the drawing element appears to have some tactile quality due to the first enhanced tactile area, the drawing element and the first enhanced tactile area together forming a security feature. In one embodiment, the tactile layer is a transparent or translucent paper-like touch layer.

[0083] In one embodiment, the first enhanced tactility zone has ends that are not substantially larger than the ends of the drawing element.

[0084] In one embodiment, the first enhanced touch zone comprises a pattern of enhanced touch sub-zones, the sub-zones preferably being lines and / or dots.

[0085] In one embodiment, the enhanced tactile layer contains tactile particles, the tactile particles preferably having a dimension which has an average size of 5 to 70 microns.

[0086] In one embodiment, the tactile particles have an average diameter of approximately 20 microns and, preferably, are spherical.

[0087] In one embodiment, the tactile particles are retroreflective, or semi-retroreflective.

[0088] In one embodiment, each printing layer is a layer printed by intaglio. In another embodiment, at least one printing layer is a layer printed by intaglio, and at least one printing layer is a layer printed by inkjet.

[0089] According to a fifth aspect of the present invention, a banknote is made available having a substrate having polymeric outer surfaces, including a coating, which coating is a paper-touch layer applied to at least one of the outer surfaces, which offers a sensation substantially similar to that of a paper banknote, the paper-touch layer including tactile particles, to provide the paper-touch feel, and the tactile particles being conductive and / or the paper-touch layer including conductive particles, to improve the antistatic properties of the banknote.

[0090] In one embodiment, the tactile particles have a depth of 5 to 35 microns, and preferably even more, the particles have an aspect ratio between substantially 1 and 5.

[0091] In one embodiment, the tactile particles have, at least on average, a dimension in at least one direction that is greater than 150% of the smallest dimension.

[0092] In one embodiment, the paper-touch layer contains approximately 5% to 20% by weight of tactile particles relative to the ink, preferably approximately 10% to 15%. In one embodiment, the tactile particles consist of one or a combination of polyethylene, polypropylene, glass, acrylic, polyurethane, ceramic, or rubber.

[0093] In one embodiment, the paper-touch layer has an average particle depth to binder depth ratio in the range of 3:1 to 7:1. In one embodiment, the paper-touch layer is applied in a first thickness in first regions and a second thickness in second regions, the second regions offering improved tactility.

[0094] In one embodiment, the quantity of conductive particles is appropriately determined so that the paper-touching layer has a surface resistivity of less than 1011 Ohms per square.

[0095] In one embodiment, the conductive particles are a fibrous conductive filler material which is a fibrous core material on which a conductive layer, the conductive particles preferably containing at least one tin oxide and one antimony oxide.

[0096] In one embodiment, the fibrous conductive charge material particles have an average length of 3 to 50 microns, preferably the fibrous conductive charge material particles have an average diameter of 0.01 to 5 microns, and preferably still, the fibrous conductive charge material particles have an average aspect ratio of 3 to 100.

[0097] In one embodiment, the conductive particles are provided in the paper-touching layer at a concentration of approximately 10% to 15% by weight.

[0098] In one embodiment, the coating is applied to the entire banknote, such that the banknote has a paper-like layer all over it, but it can be applied selectively for design or process considerations. For example, when the banknote has a transparent window, or other security feature, it may be chosen not to print the coating in that area.

[0099] In one embodiment, the coating is an exterior coating.

[0100] In one embodiment, the coating includes a UV-cured sand ink.

[0101] In one embodiment, the coating includes a solvent-based ink.

[0102] According to a sixth aspect of the present invention, a ticket is made available banknotes having a coating, which coating is a transparent or translucent layer applied to the banknote, which includes conductive particles.

[0103] In one embodiment, the coating is an exterior coating.

[0104] In one embodiment, the quantity of conductive particles is determined in an appropriate manner so that the coating has a surface resistivity of less than 1011 Ohms per square.

[0105] In one embodiment, the conductive particles are a fibrous conductive filler material which is a fibrous core material on which a conductive layer is formed, the conductive particles preferably containing at least one tin oxide and one antimony oxide.

[0106] In one embodiment, the fibrous conductive filler material particles have an average length of 3 to 50 microns, preferably the fibrous conductive filler material particles have an average diameter of 0.01 to 5 microns, and preferably still, the fibrous conductive filler material particles have an average aspect ratio of 3 to 100.

[0107] In one embodiment, the conductive particles are provided in the coating at a concentration of approximately 10% to 15% by weight.

[0108] According to a seventh aspect of the present invention, a banknote is made available having a substrate having polymeric outer surfaces, including a coating, which coating is a touch layer applied to at least a part of one of the external surfaces having touch particles which have a size of 5 to 35 microns in at least one dimension, and, preferably still, the touch particles have an aspect ratio between substantially 1 and 5, the touch layer being applied in a first thickness in first regions and a second thickness in second regions.

[0109] In one embodiment, the tactile particles have, at least on average, a dimension in at least one direction that is greater than 150% of the smallest dimension.

[0110] In one embodiment, the tactile particles offer a sensation substantially similar to that of a paper banknote, at least in the first regions.

[0111] In one embodiment, the tactile layer includes conductive particles. In one embodiment, the conductive particles are a fibrous conductive filler material which is a fibrous core material on which a conductive layer is formed, the conductive particles preferably containing at least one tin oxide and one antimony oxide.

[0112] In one embodiment, the fibrous conductive charge material particles have an average length of 3 to 50 microns, preferably the fibrous conductive charge material particles have an average diameter of 0.01 to 5 microns, and preferably still, the fibrous conductive charge material particles have an average aspect ratio of 3 to 100.

[0113] In one embodiment, the quantity of conductive particles is appropriately determined so that the paper-touching layer has a surface resistivity of less than 1011 Ohms per square.

[0114] In one embodiment, the conductive particles are provided in the paper-touching layer at a concentration of approximately 10% to 15% by weight.

[0115] In one embodiment, the coating includes a UV-curable ink.

[0116] In one embodiment, the coating includes a solvent-based ink.

[0117] According to an eighth aspect of the invention, a tactile security feature is made available for a banknote including a printed design layer having a print depth of 5 microns or less, a printed tactile layer, having tactile particles, printed on the design layer, the tactile layer giving apparent tactility to the design layer.

[0118] According to a ninth aspect of the present invention, a tactile security feature is provided for a banknote having a printed marking layer including a design element and a printed enhanced tactile layer, which has at least a first overlapping enhanced tactile zone / covering the drawing element, in such a way that the drawing element appears to have some tactility due to the overlap / overlap of the first enhanced tactility zone, the drawing element and the first enhanced tactility zone together forming the security feature.

[0119] In one embodiment, a lateral extent of the first enhanced tactility zone substantially corresponds to a lateral extent of the drawing element.

[0120] In one embodiment, the enhanced tactility layer contains tactile particles, the tactile particles preferably having at least one dimension which has an average size of 5 to 70 microns.

[0121] In one embodiment, the tactile particles are made of one or a combination of polyethylene, polypropylene, glass, acrylic, polyurethane, ceramic or rubber.

[0122] In one embodiment, the tactile particles have an average diameter of approximately 20 microns and, preferably, are spherical.

[0123] In one embodiment, the touch particles have a size of 5 to 35 microns in at least one dimension, and, preferably still, the touch particles have an aspect ratio between substantially 1 and 5, the touch layer being applied in a first thickness in first regions and a second thickness in second regions.

[0124] In one embodiment, the tactile particles have, at least on average, a dimension in at least one direction that is greater than 150% of the smallest dimension.

[0125] In one embodiment, the tactile particles are retroreflective, or semi-retroreflective.

[0126] According to a tenth aspect of the invention, a printing press is made available for the production of a plurality of banknotes on a continuous substrate strip, the printing press including a plurality of printing units of the same type of printing process, the plurality of printing units comprising at least one printing unit configured to print a marking layer and at least one printing unit configured to print a tactile layer on the substrate in the same printing pass.

[0127] Embodiments of the tenth aspect of the invention may include embodiments corresponding to any of the preceding aspects, in particular the first or second aspect.

[0128] In one embodiment, each of the plurality of printing units is an intaglio printing unit, and, in another embodiment, an intaglio cylinder of at least one printing unit configured for printing a touch layer is configured to print an ink containing particles.

[0129] In one embodiment, the printing press comprises a plurality of printing units configured to print marking layers onto the substrate, and, in an additional embodiment, a plurality of printing units configured to print tactile layers onto the substrate. In another embodiment, the printing press comprises a corresponding plurality of drying units.

[0130] In one embodiment, the printing press includes a first plurality of printing units configured to print at least one marking layer and at least one tactile layer on a first surface of the substrate, a flipping bar for flipping the substrate after it has passed through the first plurality of printing units, and a second set of printing units configured to print at least one marking layer and at least one tactile layer on a second surface of the substrate after it has been flipped by the flipping bar.

[0131] In one embodiment, the printing press includes one or more additional printing units of a different printing process type than the plurality of printing units. In one embodiment, at least one additional printing unit is configured to print a different printing layer design on at least two of the plurality of banknotes on the continuous substrate web, preferably on each of the plurality of banknotes. In one embodiment, at least one additional printing unit is an inkjet printing unit.

[0132] In one embodiment, the printing press includes a corona discharge machine that treats both surfaces of the substrate by corona discharge to increase the adhesive properties of the substrate surface. Optionally, the printing press may include an inspection system and may further optionally include a guillotine cutter for cutting the continuous substrate strip into sheets. Alternatively, the printing press may include a winding system configured to store the continuous substrate strip after it has been printed.

[0133] Definitions Banknote

[0134] As used here, the term "banknote" refers to all valuable documents used in transactions. Banknotes are a special case of security documents because they are in large quantities, are the subject of a very large number of transactions, and are subject to heavy wear and tear. Due to this heavy wear and tear, solutions Methods suitable for other security documents are often not suitable for banknotes, particularly with regard to the adhesion of an element, such as printed ink or a security feature, to the banknote substrate.

[0135] Safety Device or Feature

[0136] As used herein, the term "security device or feature" includes any of a large number of security devices, elements or features designed to protect the banknote from counterfeiting, copying, alteration or falsification.Security features or devices may be implemented in or on the banknote substrate or in or on one or more layers applied to the base substrate, and may take a variety of forms, such as security threads embedded in banknote layers; security inks such as fluorescent, luminescent and phosphorescent inks, metallic inks, iridescent inks, photochromic, thermochromic, hydrochromic or piezochromic inks; printed and embossed features, including raised structures; interference layers; liquid crystal devices; lenses and lenticular structures; optically variable devices (OVDs) such as diffractive devices including diffraction gratings, holograms, diffractive optical elements (DOEs).

[0137] Substrate

[0138] As used herein, the term "substrate" refers to the base material from which the banknote is formed. Unless otherwise specified, the base material may be paper or another fibrous material, such as cellulose; a plastic or polymer material (the two terms being interchangeable) including, but not limited to, polypropylene (PP), polyethylene (PE), polycarbonate (PC), polyvinyl chloride (PVC), polyethylene terephthalate (PET), biaxially oriented polypropylene (BOPP); or a composite material of two or more materials, such as a laminate of paper and at least one plastic material, or of two or more polymer materials. In particular, the base material may be a polymer film that is opacified during manufacturing, for example by the addition of titanium dioxide or the creation of air bubbles.

[0139] Opacifying layers

[0140] One or more opacifying layers may be applied to a transparent or translucent substrate to increase the opacity of the security document. An opacifying layer is such that LT < Lo, where Lo is the amount of light incident on the document and LT is the amount of light transmitted through the document. An opacifying layer may comprise any one or more of various Opaque coatings. For example, opacifying coatings may include a pigment, such as titanium dioxide, dispersed in a binder or a heat-activated, crosslinkable polymer support. Alternatively, a transparent plastic substrate could be sandwiched between opacifying layers of paper or another partially or substantially opaque material onto which markings can then be printed or otherwise applied.

[0141] Touch paper

[0142] As used here, the term "paper feel" refers to a particular tactile sensation (tactility) or haptic property on the hardened, printed portion of the surface. Because the haptic properties of paper feel are typically measured by human touch, they are somewhat subjective. In the coatings industry, it is more common to use the term "soft feel," and, in some cases, "paper-like soft feel," and the term "paper feel" is a subset of "soft feel." Overall, a layer or print described as having a "paper feel" indicates that the surface of the described layer has a feel similar to that of a similar paper-based product, in which the surface roughness of the paper product is detectable by the sense of human touch.As such, a paper-like coating or print represents an increase in surface roughness for polymer substrates, which are typically very smooth. One method for quantifying this surface roughness is to measure the coefficient of friction. What proves particularly relevant to the term "paper-like" as used here is a comparison with paper banknotes. Different paper banknotes have different coefficients of friction. For example, a US dollar bill has a value of 0.1716, a 10 euro bill has a value of 0.1078, and a 10,000 Korean won bill has a value of 0.1563 – Song, Han Wook & Woo, Sam Yong & Kyu Park, Yon & Lee, Sungjun. (2008). "Measurements of the Friction Coefficient for Banknotes". MAPAN-Joumal of Metrology Society of India.23 - It should be noted that these measurements compare banknotes to a "Teflon®" point (used as an approximation of the human finger). Based on this data, it is reasonable to consider in this context that the feel of paper is, at the very least, a coating with a coefficient of friction between approximately 0.1 and 0.2. Another measure of the coefficient of friction is the "banknote against banknote" measurement, which is the coefficient of friction of one banknote against another. A suitable specification for this measurement of the coefficient of friction is 0.2 to 0.4, which has been confirmed by measurements (further description below).

[0143] Printing process

[0144] Many different types of printing processes are used for printing on substrates. As discussed above, for the traditional banknote industry, the typical types of printing processes implemented are sheet-fed offset printing and sheet-fed intaglio printing. More specifically, a substrate is fed in sheets to an offset printing press and then, separately, to an intaglio printing press. Other types of printing processes commonly found both in and outside the security industry include letterpress, intaglio, flexography, and inkjet printing. All of these printing processes require specific types of substrate feed, printing equipment, and inks.In general, while all types of printing processes can be configured to be fed by a substrate web, the types of printing processes that can operate at the highest speeds, and therefore at the lowest costs, are flexography and intaglio printing. As described in more detail below, the generic term intaglio printing can be used to cover printing techniques in which an image is incised into a surface, and the incised line or recessed area retains the ink for printing. However, in printing, and particularly in security printing, a distinction is made between the printing processes of intaglio (also known as rotogravure) and intaglio (also known as intaglio).Anyone skilled in the art of security printing will immediately understand that an intaglio printing process involves high-viscosity ink applied to lines incised into an intaglio printing plate, which is then pressed under high pressure onto the substrate. Similarly, anyone skilled in security printing will immediately understand that an intaglio printing process refers to lower-viscosity inks drawn from an ink bath by a cylinder in which "cells" are etched and then applied to a strip of substrate. Therefore, any reference to printing units of the same type of printing process in this description refers to printing units of a single, specific printing process, as in the examples given above, as anyone skilled in security printing will readily understand. Figures

[0145] We will now describe embodiments of the invention with reference to the accompanying drawings. It will be understood that the embodiments are given by way of illustration only and that the invention is in no way limited by this illustration. In the drawings:

[0146] [Fig.1A] is a schematic illustration of a printing press configured to produce a banknote according to at least one aspect of the present invention;

[0147] [Fig. IB] is a flowchart of a process for producing a banknote according to at least one aspect of the present invention;

[0148] [Fig.2A] is an exploded cross-sectional view of a banknote according to one or more aspects of the present invention;

[0149] [Fig.2B] is a cross-sectional view of a banknote according to one or more aspects of the present invention;

[0150] [Fig.3] is a schematic view of a coating according to one aspect of the present invention;

[0151] [Fig.4A], [Fig.4B], [Fig.4C] are graphic representations of a form of realization of a tactile safety feature according to one aspect of the present invention; and

[0152] [Fig.5A], [Fig.5B], [Fig.5C] are graphic representations of a form of realization of a tactile safety feature according to one aspect of the present invention. Detailed description of the invention

[0153] As indicated above, numerous disadvantages are associated with known methods of producing banknotes. In particular, separate printing processes are required, which increases the cost and time needed to produce banknotes with little or no additional security features. More specifically, the fact that separate printing processes are used is not considered a deterrent to counterfeiters.

[0154] However, there are several characteristics that the general public recognizes when handling banknotes, which are distinct from specific security features. These are: print quality and the "feel" of the banknote. Print quality on modern banknotes is not an obstacle to counterfeiting, but in general, the public will immediately be suspicious of banknotes that do not have high print quality. As such, it acts as an early warning sign, and counterfeiters often produce poor-quality forgeries. The "feel" of the banknote comes down to several factors, but in particular, the substrates and printing techniques used on banknotes have remained similar for many years, so the public trusts banknotes that have a similar feel to those they have handled in the past.

[0155] The "feel" of a conventional banknote typically comes from two different sources: the substrate from which the banknote is made and the printing design Intaglio printing is used on banknotes. Traditional paper substrates feel slightly rougher than more modern polymer banknotes, especially in areas without intaglio printing. Offset printing, used for background designs, leaves no noticeable tactile characteristics and tends to replicate the feel of the substrate on which it was printed. Banknotes without intaglio printing have a very smooth feel compared to those with it.

[0156] It is important to note that the generic term intaglio printing can be used to cover printing techniques in which an image is incised into a surface and the incised line or recessed area retains the ink for printing. However, in printing, and particularly in security printing, a distinction is made between rotogravure printing and intaglio. In rotogravure, the printing surfaces are cylinders that are produced, for example, by an electron beam, a laser beam, or an engraver. Rotogravure is distinguished by the fact that different shades of gray or color of the printed image are produced by cells of varying densities, sizes, and / or depths arranged regularly on the cylinder.A signature of intaglio printing lies in the slightly jagged, straight edge, typically visible only under magnification, which is an artifact of the cell structure. This signature is also visible in a total variation of an image. An important aspect of intaglio printing lies in the selection of appropriate cell structures and repetitions, or lined patterns, of the cells.

[0157] In contrast, in intaglio printing, linear grooves are formed in the printing plates to produce a printed image. In a mechanically produced intaglio plate, a wider line is produced with a greater engraving depth due to the typically tapered engraving tools. Furthermore, the ink receptivity of the engraved line, and therefore the opacity of the printed line, increases with increasing engraving depth. In chemical etching of intaglio plates, the non-printing areas of the plate are coated with a chemically inert lacquer. Subsequent chemical etching etches the exposed plate surface, the depth of the etched lines depending particularly on the chemical etching time and the line width. Due to the depths used, the type of ink and the pressures required for intaglio printing are very different from those of intaglio printing.As such, the yield of intaglio engraving, which is typically a tape-fed, reel-fed process, is considerably higher.

[0158] The Intaglio technique, in particular the Intaglio technique using a steel plate, produces a characteristic printed image that is easily recognizable by a layperson and is not typically considered reproducible with other conventional printing processes. If the engravings made in the printing plate are sufficiently deep, a data carrier printed by Intaglio produces, through embossing, due to the high pressures used, and inking, a printed image that forms a relief perceptible to the touch.

[0159] Method for producing a banknote and printing press for producing a plurality of banknotes

[0160] With reference now to Figures IA and IB, we will now describe aspects of the present invention, which is a method for producing a plurality of banknotes and a printing press for producing a plurality of banknotes. With regard to [Fig. 1A], a substrate 10, in the form of a continuous strip of polymer material, is located on a reel 12 at one end of a printing press 14. In this example, the printing press 14 is an intaglio printing press, in that the printing process used to apply printing layers is intaglio printing. The substrate 10 is unwound from the reel 12 and passed through the printing press 14. The printing press 14 comprises a corona discharge machine 16, a plurality of intaglio printing units 18, and a turning bar 20.The substrate 10 is fed into the corona machine 16, which treats both surfaces of the substrate 10 by corona discharge, thereby increasing the adhesive properties of the substrate surface 10 or its coatings. Upon exiting the corona machine 16, the substrate 10 is fed to a first set A of printing units 18 before being turned over at the turning bar 20, and then to a second set B of printing units 18. Each printing unit 18 applies a printing layer to the substrate 10. Each printing unit 18 has a corresponding drying or curing unit 22. In this example, the drying unit 22 includes an air heater that raises the temperature of the substrate 10 and promotes the drying or curing of the printed layer applied by the corresponding printing unit 18.Depending on the ink and printing system used, appropriate drying or curing units may be used instead of drying units 22.

[0161] Figure 1B describes a process 40 for producing a banknote. In a first step 42, a substrate, in the form of a strip, is fed to a printing press, the printing press comprising a plurality of printing units of the same type of printing process. More specifically, for example, if the type of printing process were intaglio printing, the printing units would be intaglio printing units, it being understood that each individual unit may be of a different configuration and, possibly, print a different type of ink, but the printing unit conforms to what a person skilled in the art would recognize as an intaglio printing unit. In step 44, the web is passed through each unit of the plurality of printing units. In step 46, at least a portion of the web is printed in a printing pass, printing a printing layer on the web. In step 46, at least one of the plurality of printing units prints a marking layer and at least one of the plurality of printing units prints a tactile layer. The process 40 may optionally include the additional steps described with respect to the printing press in [Fig. 1A].

[0162] Importantly, the method for producing a banknote and a printing press for producing a plurality of banknotes includes printing at least one marking layer and one tactile layer by the printing units 18. The tactile layer may be either a layer intended to provide specific tactility to one or more design elements, or a layer designed to give the banknote a particular type of feel, such as the sensation that the material is made of paper, or a combination of both. It is also possible that several tactile layers may be present, providing one or more of the tactile functions mentioned above.

[0163] In the normal production of a banknote according to this process, more than one of the printing units 18 would print a marking layer. For example, a marking layer would typically be required for each color on the banknote, on each side of the banknote.

[0164] In the context of all embodiments of the invention, a marking layer is a layer which, alone or in combination with other marking layers, produces markings, which are one or more design elements that provide the context of the issuing bank or country, the associated value and / or denomination, or some other recognizable element, such as text, a number, images of portraits, objects, or scenes, and the like. Typically, a banknote features a prominent identity of the issuing country, with numbers indicating the denomination, and one or more marking layers would provide these types of features. Importantly, a marking layer is not considered to be an opacifying layer, even if the marking layer has some effect on the opacity of the banknote, because its intended use is not to make it opaque but to produce a visual design or marking.As used elsewhere in this description, the term "marking" should be interpreted as described above.

[0165] In the context of all embodiments of the invention, a tactile layer is a layer that imparts an increased degree of tactility to the substrate and / or the layer on which it is deposited. For example, if the substrate on which the tactile layer is printed has a coefficient of friction of 0.1, then the tactile layer is expected to have a higher coefficient of friction. A tactile layer intended to provide a "paper feel" has characteristics designed to mimic the feel of paper banknotes, as described above. A tactile layer that is an enhanced-tactility layer provides additional tactility. In at least some embodiments, this enhanced-tactility layer is intended to provide an "Intaglio-type" feel, which is the tactility provided by Intaglio printing on known banknotes.

[0166] The marking layers produced in this process can have much tighter tolerances than banknotes of the prior art. For example, on an intaglio printing press, since the printing layers are printed inline, the alignment tolerances are about 100 microns and a maximum of 300 microns, compared to about 1.4 mm, or 1400 microns, with banknotes of the prior art which require separate printing processes.

[0167] A printing press 14 includes, in addition to the plurality of intaglio printing units 18, one or more additional printing units 19 of a different type of printing process. As described in [Fig. 1A], the substrate 10 is fed to inkjet printing units 19, each of which applies an inkjet printing layer to the substrate 10 in the same printing pass in which the intaglio printing units 18 print intaglio printing layers onto the substrate 10. The inkjet printing units 19 have corresponding drying or curing units 23, for example a UV lamp, to activate the curing of a UV-curable inkjet ink printed by the inkjet printing units 19.It will be understood that the additional printing units can be suitably provided in line, at various locations on the printing press 14, for example before or after the plurality of intaglio printing units 18, or interleaved between intaglio printing units 18, as described in [Fig. 1A]. The use of additional printing units can offer additional advantages in the process of the invention. In particular, inkjet printing units 19 offer the ability to personalize each banknote individually, for example by printing a unique serial number or barcode / QR code on each banknote. Alternatively, the additional printing units can be used to print one or more additional marking layers. in addition to the marking layer or layers printed by the intaglio printing units 18. However, although additional printing units 19 are a preferred feature of the example described in [Fig.1A], it will be understood that they are not generally required in the processes according to the invention.

[0168] An example of a suitable inkjet printing unit is a Domino Trimatt K600i inkjet printer, configured for web printing. These printers are capable of printing with UV-curable inks, which have suitable compatibility with printing layers printed by intaglio engraving according to embodiments of the invention.

[0169] In the example described in [Fig. 1A], a corona machine 16 is used to promote the adhesion of the ink to the polymer material web. This is the preferred method for promoting adhesion, but other methods can be used, such as plasma treatment or the application of an additional adhesion-promoting layer. For example, an adhesion-promoting layer can be printed, or otherwise produced, on the polymer material web. This step could be carried out during the manufacturing of the polymer material, in a separate process step or in line with the printing units 18, or by one of them. However, the corona machine 16 and any other method of promoting adhesion, although preferred, are optional. Adhesion promotion is, of course, itself an optional step in the present invention and may or may not be required.For example, as will be described below, paper substrates do not require such steps.

[0170] Importantly, banknotes generally have adhesion requirements that are considerably different from those of other printed products. Banknotes are essentially reusable products that are subject to heavy wear and tear and chemical exposure environments. As such, they must pass adhesion tests that are much more stringent than the normal requirements for printed products. For example, a commercially available "crease testing apparatus," specifically for testing banknotes for crease resistance, is available from IGT Testing Systems, Singapore. Typically, adhesion is tested after a specified number of "creases" by an "adhesive tape test," in which an adhesive strip is placed on the banknote and then removed.If the adhesive strip removes more than a specified percentage of the printed ink, the product may be considered to have insufficient adhesive properties. This is a more stringent adhesion test than for other security documents because banknotes require significantly stronger adhesion. Furthermore, banknotes also require enhanced wear resistance characteristics compared to other security documents, as wear and tear cannot be tolerated. It cannot be solely associated with adhesion. One such method for measuring wear resistance involves using an abrasion machine to perform an accelerated wear test. For example, a TABER® Rotating Platform Abrasion Tester can be used for this accelerated wear test.

[0171] The substrate 10 is then conveyed to an inspection system 24. The inspection system 24 takes images of the printing layers and quantifies the print quality and the register alignment of the printing layers. The inspection system 24 then provides feedback to the printing units 18, which can automatically adjust to correct, at a minimum, the register alignment, and in some cases, other print quality issues. The inspection system 24 also reads a unique identifier printed either above or below each banknote, so that banknotes printed with detected defects are recorded as such in the system.

[0172] The substrate 10 is then fed into a guillotine machine 26 which cuts the substrate 10 into individual banknotes, or, if desired, into sheets of banknotes. In either case, the guillotine machine 26 automatically separates banknotes printed with defects and sends them to a defective banknote pile 28. Banknotes that are not detected as having any defects are sent to a finished banknote pile 30.

[0173] It will be understood that the inline inspection system 24 and the guillotine machine are preferable features of the example described in [Fig. 1A]. Many of the advantages offered by this banknote production process are obtained by a web-fed printing press, which does not have these inline systems. In another embodiment, the printing press 14 has a winding system (not shown) after the last printing unit and either does not have an inline inspection system, or does not have a guillotine machine, or does not have either. These systems can then be provided as offline process steps to generate the final banknotes.

[0174] It will also be understood that the advantages of printing a banknote using a single printing press are obtained most of the time even if each side of the banknote has been printed in separate printing processes on the same printing press. More specifically, although it is preferable for both sides to be printed in a single printing pass, the advantages of reduced handling, improved adhesion, and register alignment are still obtained with printing only one side at a time.

[0175] Furthermore, although the above process is described as using a polymer material as a substrate, the advantages of this process are obtained using any substrate. More specifically, higher yield and lower handling, Among other advantages, they are not substrate-dependent. The use of traditional paper as a substrate is also suitable. However, a polymer material is preferred because its smoother surface allows for higher printing resolution, as ink penetrates or moves along the paper fibers, causing smudging and imposing a lower resolution requirement. As described elsewhere, imparting a paper-like feel to a polymer substrate is a particular advantage of embodiments of the invention.

[0176] Banknote

[0177] Let us now refer to [Fig. 2A], which is a schematic cross-sectional representation of a banknote 50 produced, for example, by the process described and by the printing press illustrated according to [Fig. 1A] and [Fig. 1B]. The banknote 50 comprises a polymer film substrate 52, which, in this example, is an opacified polymer film. Preferably, it is a polymer film that is opacified during the film's manufacture itself, by the inclusion of an opacifying additive in the polymer during extrusion. More precisely, the polymer film is opacified due to its bulk properties rather than by the addition of opacifying layers. One such example of a suitable polymer film is biaxially oriented polypropylene (BOPP) to which titanium dioxide (TiO2) has been added during manufacture to create a white polymer film.Alternatively, substrate 52 could be a transparent polymer film opacified by the application of one or more opacifying layers, such as Guardian®.

[0178] A polymer film that is opaque throughout, rather than by the addition of opacifying layers, offers a number of distinct and surprising advantages. In particular: • Over the lifespan of a banknote, one characteristic of wear is creasing. In substrates based on an opaque transparent film, such as Guardian®, such creasing causes a loss of adhesion at the point where the banknote is creased, creating "crease lines," which are lines where the amount of opacifying ink has been reduced or where there is no opacifying ink at all. Because the polymer film is opaque throughout, there is no break in opacity due to creasing. Opaque inks applied to a transparent film are typically solvent-based. Generally, four to six layers of opacifying inks are applied to provide the desired opacity. Furthermore, these layers are almost completely opaque, except for windows or shadow images. As such, there is a quantity A significant amount of solvent evaporates, generating a large quantity of volatile organic compounds (VOCs) as a byproduct of the printing process. Using a polymer film that is opaque throughout significantly reduces the amount of solvent used, as there is no need for opacifying inks, thus considerably reducing the amount of VOCs released, resulting in a more environmentally friendly product and process. • A banknote is preferably about 70 to 110 microns thick. For a transparent film with opacifying layers, such as Guardian®, the film is typically about 75 microns thick, with the remaining thickness provided by the opacifying layers, resulting in approximately 12 to 18 microns of opacifying layers. For a polymer film that is opacified throughout, the light-diffusing layer (which produces the opacification) has at least 70 microns of thickness to diffuse the light, rather than only about 18 microns. This results in greater opacity and reduced "show-through." Show-through is the situation in which, through transmission, it is possible to see features on the opposite side of the banknote.A reduced transparency is particularly advantageous because it reduces the need for the markings on each side of the banknote to be complementary, thus avoiding the creation of an undesired design. Opacified layers on a transparent film can also cause mechanical failure of other features, such as printing or security features, if the integrity of the opacified layer is compromised (for example, by crease lines as described above). A polymer film that is opacified throughout prevents these problems, because only the adhesion of the other features to the film matters, not the adhesion of the feature to the opacified layer.

[0179] The substrate 52 is preferably 70 to 110 microns thick, more preferably 80 to 100 microns thick, and preferably approximately 90 microns thick. A thickness of about 90 microns results in a final banknote product with properties that are easily recognizable to the general public in terms of flexibility, thickness, and feel, as being similar to those of banknotes produced in the past, such as those made of paper. This is particularly true for polypropylene polymer substrates and, in particular, BOPP substrates. This allows for greater public acceptance when a new banknote is issued. Furthermore, this thickness also provides the best suitability for processing by automatic banknote processing machines, as it also corresponds to the thicknesses that automatic banknote processing machines would typically process.

[0180] Furthermore, producing polymer films of this type with thicknesses exceeding 70 microns is difficult and requires significant technical expertise and capital. As such, suppliers of these specialty polymer films are large companies and can be easily identified. This increases the security of the banknote, as obtaining polymer films of this thickness, particularly in polypropylene, and even more so in BOPP, is extremely difficult.

[0181] The substrate 52 has a number of printing layers applied to each face, each printing layer being applied using the same printing process. More specifically, each printing layer is applied simultaneously or consecutively in the same printing pass on at least one face of the substrate. In the embodiment of [Fig. 2A], a front face 54 of the banknote 50 has marking layers 56A, 58A, and 60A, which are three distinct colors applied in a desired design. The printing layer 62A is, in this example, a coating that is typically applied to the entire banknote but may be excluded in certain areas, such as windows, and that provides some protection to the underlying printing layers as well as other desirable functions, as described in more detail below.The preferred embodiment of this coating offers several distinct advantages, which are described in more detail below. Generally speaking, the coating is a tactile layer with added particles that provide a visual and tactile sensation similar to paper.

[0182] In this example, a back side 64 of the banknote 50 has printed layers similar to those described for the front side 54. More specifically, marking layers 56B, 58B and 60B are three separate colors applied according to a desired design and a printing layer 62B is a coating that is typically applied to the back side 64. However, it will be understood that the marking layers 56B, 58B and 60B need not necessarily correspond in color and design to the marking layers 56A, 58A and 60A, just as there does not need to be a tactile layer similar to the printing layer 66 (described below).

[0183] On the front face 54, an additional printing layer 66 is applied over the top coating 62A. The printing layer 66 is an enhanced tactile layer formed of an ink, lacquer, or other suitable material, comprising particles. In this case, the particles are large enough to protrude from the lacquer, ink, or other suitable material, and provide a tactile sensation considerably rougher than that of the top coating. The enhanced tactile layer, in conjunction with other components of the printing layers, forms an important security feature of the 50 banknote and is described in more detail below.

[0184] A banknote as described in relation to [Fig. 2A] has several special advantages over previously produced banknotes. First, the banknote is produced in a continuous web printing process. In one embodiment, the inks used in the web printing process are of the same type and are all designed for the same type of printing. In another embodiment, the inks are all suitable for a web printing process, but are not necessarily of the same type of printing process. In the preferred example, the inks are all intaglio inks and the printing layers are all printed using an intaglio printing process.There are a number of distinct advantages offered by a banknote made up of printing layers that are suitable for printing in the same tape printing process, in particular: .

[0185] 1. The inks can all be of the same type and therefore they all have the same, or substantially the same, Hansen Solubility Parameters (HSP), one advantage of which lies in the fact that the adhesion between the printing layers is improved compared to printing layers printed with different inks, and therefore having relatively different HSP parameters. This advantage manifests itself in improved wear resistance characteristics compared to banknotes with different printing processes for depositing ink layers, which means a longer lifespan for a banknote produced according to the invention. The details and advantages of a specific type of ink system will be described in more detail below.

[0186] 2. Printing layers are deposited sequentially, in the case Intaglio and flexographic printing presses, and other similar printing presses, typically operate at a relatively high speed. This means that while one printing layer may be sufficiently dry for an additional printing layer to be added, each printing layer is not fully dried / cured once all printing layers have been applied. As such, the printing layers dry or fully cure while in contact with each other, creating improved adhesion between the printing layers compared to printing on fully dry / cured layers, resulting in enhanced wear resistance.

[0187] 3. A register alignment between the ink layers can be controlled to a degree higher, which reduces the overall system tolerances. For example, a typical offset press will have color alignment variances of + / - 1 mm or more, although a specialty press like Shnultan can have variances as low as 50 microns, and a register between printing steps on different printing presses would be around 1.4 mm. In, for example, an intaglio printing press, the tolerances from one unit to another would typically be 100 microns, and at most 300 microns. As such, using only one type of printing process significantly reduces printing tolerances, especially between printing units.

[0188] Another embodiment uses radiation-curable inks suitable for web printing presses for layer printing, preferably UV-curable inks. Again, other preferred embodiments are radiation-curable inks suitable for an intaglio printing press. UV-curable inks, as well as other radiation-curable inks, are inks in which UV (or other radiation) initiates a photochemical reaction that generates a cross-linked polymer network. Most radiation-curable inks do not require solvent, which allows for a higher solids charge (because the ink-retaining elements on printing cylinders are not partially bound with solvent in the ink, which eventually evaporates).In some cases, a minor amount of solvent may be used to achieve a suitable partial viscosity for printing, but this is a significantly reduced amount of solvent.

[0189] As such, radiation-curable inks have the following advantages: the fact that the photochemical reaction which occurs in a radiation-curable ink is very rapid and, as such, there is almost no drying requirement; the absence of solvents means that there is no, or much less, release of VOCs (volatile organic compounds); and radiation-curable inks have proven to be very resistant to wear, which is a particular advantage for a banknote.

[0190] Appropriate ink systems, printing layers and features for a banknote according to this embodiment are described below.

[0191] Single ink system

[0192] Banknotes are produced using a chemical composition of ink based on a number of different ink systems, the majority of which rely on oxidation in air. More specifically, the majority of banknote inks are oil-based inks, which oxidize in the presence of air and metallic soaps to form cross-linked structures. There is also an increasing use of inks cured using actinic radiation, which requires additional equipment, such as UV lamps.

[0193] Inks used for polymer and hybrid substrates used in security documents have a different chemical composition and usually employ crosslinking using a range of chemical curing compositions, typically resulting in a highly crosslinked, high molecular weight polymer system. This is because inks used for traditional paper substrates are able to penetrate the fibers of the paper substrates and, consequently, have relatively good adhesion to the substrate. With a polymer substrate, traditional inks cannot penetrate the surface, and if they were used, the adhesion of the inks to the polymer substrate would not be sufficient to provide a banknote's service life. Therefore, a highly crosslinked system is required so that the ink crosslinks strongly to the polymer substrate and provides high durability.The Guardian® substrate offers precisely this system with the ink used, also providing a suitable surface to which traditional offset and intaglio inks, as well as inks from other printing processes, can adhere. However, on banknotes using a Guardian® substrate, it has been observed that the offset and intaglio inks on the banknotes are more prone to wear than the white inks used to opacify the transparent polymer. More specifically, the offset and intaglio inks adhere less strongly to the white opacifying ink than the white opacifying ink adheres to the polymer substrate.

[0194] There are a number of reasons for this difference in adhesion: 1. First, there is usually a period of time (more than a day) between the production of an opaque polymer substrate for banknotes and the printing process, which involves additional steps. This is due, in part, to the need to harden and / or coalesce coatings on the substrate. During this time, not only does the surface of the materials increase in molecular weight, but its surface energy also decreases. These are desirable properties from the perspective of robustness and durability. However, this process reduces the ability of the inks applied to the surface to penetrate and achieve complete adhesion. 2. Secondly, the disparate nature of the chemical composition of the inks applied to the surface in the form of printed markings further reduces the adhesion between the surface of the material and the marking inks. 3. Thirdly, the relatively low molecular weight of the marking ink's cross-linked system compared to the surface ink results in the following: The marking ink is more flexible than surface materials and is therefore more prone to wear compared to the surface material in the same environment.

[0195] To avoid the problems mentioned above, banknotes are increasingly coated with a one- or two-layer coating system per surface after printing, in order to prevent the marking from wearing off too quickly. This process is expensive to implement and does not solve the problem but tends to minimize it. A hard coating on top of a relatively softer coating will stop some types of wear but does not solve all wear situations. For example, if a banknote is regularly crumpled, a hard coating will crack and expose the underlying softer coatings to wear.

[0196] Therefore, one embodiment of the invention relates to a banknote in which at least one drawing layer, or marking layer, and another printed layer have:

[0197] a. Hansen Solubility parameters that adequately coincide; and / or

[0198] b. hardening (increased molecular weight) by at least one crosslinking mechanism, where, preferably, the crosslinking mechanism implemented is not fully completed between the application of successive layers of ink.

[0199] Furthermore, one embodiment of the invention relates to a method for manufacturing a banknote, having inks described above, where the ink application process is implemented in the form of an online process.

[0200] Hansen Solubility Parameters (HSPs) were developed by Charles M. Hansen in his 1967 doctoral dissertation in physics (Hansen, Charles (1967), The Three Dimensional Solubility Parameter and Solvent Diffusion Coefficient and Their Importance in Surface Coating Formulation. Copenhagen: Danish Technical Press) as a means of predicting whether one material will dissolve in another and form a solution. HSPs are based on the idea that "like dissolves," where a molecule is defined as "like" another if it binds to itself in a similar way.

[0201] The ability of two polymers to intertwine or entangle, and thus to adhere to each other, depends greatly on the degree of their "similarity"—in reference to Professor Steven Abbott, "Practical Adhesion": https: / / www.stevenabbott.co.uk / practical-adhesion / hsp.php. HSPs are appropriate parameters for describing the similarity of one polymer to another and therefore their ability to adhere to each other.

[0202] In particular, each molecule has three Hansen parameters, which are each generally measured in MPa°5:

[0203] ôd - The energy arising from the dispersion forces between molecules

[0204] ôp - The energy arising from the intermolecular dipolar force between the molecules

[0205] oh - The energy from hydrogen bonds between molecules.

[0206] These three parameters can be treated as coordinates for a point in a three-dimensional space known as Hansen space. The closer two molecules are to each other in this three-dimensional space, the more likely they are to dissolve into one another. To determine whether the parameters of two molecules (usually a solvent and a polymer) are within a certain range, a value called the interaction radius (Ro) is assigned to the dissolved substance. This value determines the radius of the sphere in Hansen space, and the center of this sphere is formed by the three Hansen parameters. To calculate the distance (Ra) between the Hansen parameters for two samples 1 and 2 in Hansen space, the following formula is used:

[0207] Ra2 =4(ôdi-ôd2)2+(ôpi-ôp2)2+(ôhi-ôh2)2

[0208] It can be seen from this equation that, if the three parameters of samples 1 and 2 are close, then Ra is small and their mutual solubility / compatibility is high, so their mutual adhesion is high. If one or more values ​​differ greatly, then Ra is large and the mutual solubility is low and the adhesion is low.

[0209] Combining this with the interaction radius gives the Relative Energy Difference (RED) of the system - see HSP Basics (https: / / www.hansen-solubility.com / HSP-science / basics.php), The HSP sphere (https: / / www.hansen-solubility.com / HSP-science / sphere.php) and / or the Hansen solubility parameter on Wikipedia (https: / / en.wikipedia.org / wiki / Hansen_solubility_parameter)

[0210] RED = Ra / RO

[0211] RED < 1 the molecules are similar and will dissolve

[0212] RED = 1 the system will partially dissolve

[0213] RED > 1 the system will not dissolve.

[0214] The Hansen solubility parameters of a typical Offset and Intaglio ink resin were analyzed and the following results were found: [Tables 1] Sample dD dP dH Radius Adjustment Offset Ink 18.22 13.52 20.82 6.7 0.983 Intaglio Ink 18.63 10.51 22.59 6.5 1.000

[0215] Several inks generally suitable for polymer substrates were found through successive approximations. The Hansen solubility parameters of their resins were as follows: [Tables 2] Sample dD dP dH Radius Adjustment Var Polyester / Polyol 17.97 9.21 5.9 8.3 0.931 VMCH Vinyl Resin 17.76 10.76 6.59 6.2 0.948 VAGH Vinyl Resin 18.52 10.81 6.89 6.4 0.983

[0216] As can be seen, when comparing Offset and Intaglio resins with suitable resins for polymer substrates, there is a significant difference in the "hydrogen bonding" parameter, Δh (dH in the tables above). The difference in Δh is approximately 15 between Offset and Intaglio resins and suitable resins for polymer substrates.

[0217] The calculation of the Ra values ​​for the tested resins gave the following values: [Tables 3] Ra Offset Intaglio Polyester VMCH VAGH Offset 0 3.515836 15.53206 14.50249 15.17692 Intaglio 3.515836 0 16.75356 16.02559 16.70306 Polyester 15.53206 16.75356 0 1.709591 1.691922 VMCH 14.50249 16.02559 1.709591 0 1.034456 VAGH 15.17692 16.70306 1.691922 1.034456 0

[0218] We therefore obtain the following RED values: [Tables4] RED Offset Intaglio Polyester VMCH VAGH Offset 0 0.540898 1.871333 2.339111 2.371394 Intaglio 0.524752 0 2.018501 2.584772 2.609853 Polyester 2.318218 2.57747 0 0.27574 0.264363 VMCH 2.16455 2.465475 0.205975 0 0.161634 VAGH 2.265212 2.569701 0.203846 0.166848 0

[0219] The use of Offset resin and polyester resin in the table of suitable resins for polymer substrates gives an Ra value of 15.6, which gives a RED, Ra / R0, of 15.6 / 6.7 = 2.32 and a clear indication that the two resins are not compatible and that adhesion would be low.

[0220] In this respect, in the broadest context, the embodiment of the present invention relates to a banknote having two or more printed ink layers, at least one of which is a marking layer, each ink layer being an ink having a RED (Relative Energy Difference) less than or equal to 1 with respect to the other ink and, more preferably, less than or equal to 0.5. In certain In various embodiments, at least one other printing layer is a tactile layer, such as a paper-feel layer or an enhanced-tactility layer, as described herein. Preferably, the inks have a Hansen solubility hydrogen bonding parameter (Δh) with a difference of less than 2.5. Another embodiment of the present invention relates to a banknote in which marking ink layers have a RED (Relative Energy Difference) less than or equal to 1 relative to all other marking ink layers. Preferably, all marking ink layers have a Hansen solubility hydrogen bonding parameter (Δh) with a difference of less than 2.5.

[0221] Furthermore, one embodiment of the present invention relates to a banknote having a marking layer in which the ink has Hansen Solubility parameters having the following ranges: ôd - between 17 and 19, ôp - between 9 and 11, and ôh - between 5 and 7.

[0222] It will be understood that the Hansen Solubility parameters, and any corresponding RED value, of an ink, as described above, refer to the Hansen Solubility parameters of the relevant resin system of the ink, often called the binder. All inks have other components added, such as pigments and other additives dispersed in the binder. Before being applied / printed, one or more solvents are also included in the ink; that is, the binder is prevented from hardening by being dissolved in a solvent. However, the solvent evaporates during drying, leaving the binder and all other additives. These additives are often completely insoluble and therefore do not contribute to adhesion in the manner described above (which is why they are dispersed in the binder).It is the solubility of the binder, and its relative solubility with the binders of other inks, that is measured and referred to when discussing Hansen solubility parameters. This can be seen from the tables above, which describe suitable resins. The table referring to Offset and Intaglio inks also refers to the resins of those systems.

[0223] It is preferable that the process used to apply the ink layers be carried out on a continuous, inline strip, so that the ink layers are applied rapidly one after the other and the drying, or curing, mechanism is not completely completed between applications of the ink layers. This results in increased adhesion of the ink layers, as there are more opportunities for the layers to dissolve into one another at the boundary, thus increasing adhesion. This is true regardless of the curing mechanism, whether or not there is solvent evaporation, polymerization by crosslinking, or coalescence.

[0224] Separate process steps for the production of a banknote create printing layers that have less opportunity to crosslink or dissolve into one another and that have greater adhesion, resulting in the advantages of a banknote produced by the same printing system, as described above. Choosing an ink system with a RED value less than or equal to 1 improves adhesion characteristics, even when using disparate process steps, which may be separated in time by a considerable period of time.

[0225] Coating

[0226] A coating may provide one or more of a number of desirable characteristics to a banknote, in particular:

[0227] a paper feel, for non-paper substrates;

[0228] antistatic properties;

[0229] additional protection against wear for the features it covers;

[0230] incorporation of all additional tactile features.

[0231] A coating in the form of a protective coating, particularly for paper banknotes, is known from prior art documents. These coatings are often used to increase their durability. However, previous coatings did not use the same ink system as the one presented here, the advantages and differences of which are described above. For example, if the banknote has printed layers applied by pressure printing using intaglio printing, then a transparent intaglio ink is applied. Such a transparent ink is often called clear or transparent varnish or lacquer. Furthermore, the coating described below has several additional features not described in the prior art.

[0232] In one embodiment, a coating is created by adding particles to a transparent ink to give a "paper-like" feel. More specifically, a polymer film is typically very smooth, and inks applied to a polymer film reflect this smooth surface. The result is, for the human eye, the sensation of touching a very smooth surface. The tactile sensation is one of the most common factors used to determine the quality and authenticity of a material. This is especially true for banknotes. Therefore, reproducible tactile surfaces add an additional barrier to counterfeiting. The majority of people use paper banknotes, which are fibrous and relatively rough. Creating a polymer film with a paper-like surface is therefore desirable for banknotes.

[0233] The particles used in this embodiment preferably have an average depth of 5 to 35 microns and have an aspect ratio between Approximately 1 to 5, comparing the depth at the widest point of the particle, but preferably an average depth of 15 microns and an average aspect ratio of 3. The particles are preferably polyethylene particles, and in particular poly(ethylene terephthalate) (polyester / PET), which can be shaped to be non-spherical by forming fibers that are then sliced ​​or cut into particles with aspect ratios greater than 1. Other materials can also be used, such as polypropylene, glass, and ceramics, among others. The key component for particle retention is not the particle type but the binder depth-to-particle size ratio. More specifically, encapsulation or semi-encapsulation tends to provide greater retention.Particles that are more flexible, such as rubber-based particles, allow for a softer feel; however, polyester-based particles are preferred.

[0234] It has been found that the ideal average particle depth to binder depth ratio is ideally in the range of 3:1 to 7:1, and preferably 5:1. More specifically, if the average particle depth is 15 microns, a preferred binder depth is between 2 and 5 microns. Binder depths outside this range still provide a useful product, but either wear or tactility is reduced. It has also been found, through measurements, that a paper-like coating that adequately replicates the feel of paper banknotes has a banknote-to-banknote friction coefficient between 0.2 and 0.4 (both static and kinetic), with a preferred value of 0.3 (static, although kinetic values ​​do not vary greatly from static values).

[0235] The ink binder (once cured) is typically at a depth of about 3 microns, such that the average protrusion of a particle from the ink is 12 microns. The coating composition is approximately 5% to 20% by weight of particles relative to the transparent ink, and preferably 10% to 15%. Experimentally, this has been found to provide a suitable paper-like feel for a person with an average sense of touch.

[0236] In another embodiment, a coating is created by adding conductive particles to a transparent ink, to increase the conductivity of the banknote surface and reduce the accumulation of static electricity. The conductive particles are preferably a fibrous conductive filler material consisting of a fibrous core material on which a conductive layer is formed, such as that described in document WO1999010418A1, the contents of which are described herein by way of reference.

[0237] The fibrous filler material to be used in the invention comprises a core material for which various inorganic or organic fibrous materials having a An average length of 3 to 50 µm, an average fiber diameter of 0.01 to 5 µm, and an aspect ratio of 3 to 100 are suitable. Examples of such usable materials include potassium tetratitanate fibers, potassium hexatitanate fibers, potassium octatitanate fibers, titanium dioxide fibers, monoclinic titanium dioxide fibers, aluminum borate fibers, magnesium borate fibers, alumina fibers, wollastonite fibers, xonotlite fibers, silicon nitride fibers, boron fibers, glass fibers, silica fibers, carbon fibers, cellulose fibers, polyester fibers, and polyamide fibers. Of these, monoclinic titanium dioxide and potassium hexatitanate fibers are particularly suitable.

[0238] The fibrous conductive filler material to be used in the present invention comprises such a fibrous core material and a conductive layer formed on it and containing at least one tin oxide and one antimony oxide.

[0239] The preferred properties of the particle are a fibrous core material on which a conductive layer is formed and containing at least one tin oxide and one antimony oxide.

[0240] The fibrous conductive filler material has a volume resistivity of less than 100 Ωcm, preferably from 102 to 10 Ωcm, with 5 to 100 parts by weight of tin oxide and 0.01 to 10 parts by weight of antimony oxide per 100 parts by weight of the core material typically used for a coating. Suitable fibrous conductive filler materials are available from Otsuka Kagaku Kabushiki Kaisha under the trade name SFS.

[0241] A coating containing conductive particles should preferably have a surface resistivity of less than 10¹¹ ohms per square meter, preferably less than 10¹⁰ ohms per square meter. Providing a surface resistivity in this range helps prevent the accumulation of static electricity in banknotes and, in particular, polymer banknotes. The fibrous conductive filler material described above is particularly preferred as a conductive particle because it has been shown to provide a surface resistivity that is independent of humidity. Other conductive particles provide a surface resistivity that varies with humidity, which leads to serious processing problems in dry environments due to the accumulation of static electricity on the banknotes.

[0242] The problem of static electricity buildup is a real problem for banknote processing machines, such as automated teller machines (ATMs). If static electricity can accumulate on the banknotes, then there is a risk of double entrainment and / or banknote jamming in the machine's circuits.

[0243] The surface resistivity could be appropriately determined by printing with an ink containing a specified percentage of particles, testing the resistivity, and then iteratively adjusting the amount of particles in subsequent printing inks until the desired value is achieved. In addition to these oxides, an indium oxide, a cobalt oxide, etc., can also be used appropriately. In this case, each or one of the additional oxides is used in an amount of approximately 0.01 to approximately 10 parts by weight per 100 parts by weight of the core material. The average fiber length is 3 to 50 microns, the average fiber diameter is 0.01 to 5 microns, and the average aspect ratio is 3 to 100. The preferred average fiber length is approximately 4 microns, the preferred average diameter is approximately 0.2 microns, and the preferred average aspect ratio is approximately 20.

[0244] A fibrous conductive particle, such as the one described above, was initially rejected because it is not transparent and has a gray color. These characteristics make it suitable for use in non-transparent inks but unsuitable for transparent applications. Surprisingly, it was found that at preferred concentrations of 10% to 15% by weight in the transparent ink, preferably 12% (in the wet state, before solvent evaporation), the top coating remained transparent and retained suitable resistivity.

[0245] Although it is generally preferable for conductive particles to be added to both sides of a banknote, this is not mandatory. The dissipation of static electricity can be sufficiently controlled by placing the conductive particles on only one side.

[0246] An even more surprising embodiment of the coating was found when the "paper-like" particles described above, as well as the fibrous conductive particles described above, were incorporated into a transparent ink. Surprisingly, the transparency, paper-like feel, and conductivity were maintained, despite the effect of the two different particles on the banknote surface.

[0247] Accordingly, a preferred embodiment of the coating consists of a transparent ink having 15% by weight of paper-like particles and 12% by weight of fibrous conductive particles, as described above. An example of such an ink is: • 18% of a resin suitable for use in etching inks (such as Hitachi Chemical's TA24-548A resin); • 9% crosslinking agent, such as isocyanates; polyaziridines; zirconium complexes; aluminum acetylketone; melamines; and / or carbodiimides; • 12% of fibrous conductive particles, as described above; • 15% of particles that touch paper, as described above; • 46% solvent, suitable for dissolving the resin and catalyst, such as of MEK (methyl ethyl ketone), acetone or ethyl acetate.

[0248] Let us now turn to [Fig. 3], which is a schematic representation of a close-up of the surface of a banknote in an area where a coating 70 has been applied and includes paper-like particles 72, and which shows a close-up of fibrous conductive particles 74. The fibrous particles 74 substantially cover the surface of the coating 70, including the paper-like particles 72. The fibrous conductive particles 74 do not interrupt the paper-like feel provided by the coating, nor do they substantially affect the transparency of the coating or the colors of previously applied printed layers. The paper-like particles do not interrupt the resistivity of the coating surface, nor do they substantially affect the transparency of the overlying coating. In this respect, a particularly surprising and advantageous coating or varnish is achieved.

[0249] Clearly, when the substrate used for a banknote is paper, then the combination of paper-touch particles and conductive particles is not necessary to change the feel of the substrate.

[0250] Another embodiment of a suitable coating combines the coating described above with a tactile characteristic. More specifically, the other embodiment combines layers 62A and 66 of [Fig. 2A].

[0251] It has been found that a paper-touch ink composition, as mentioned above, can be used for both a paper-touch layer and an enhanced-tactility layer, either by printing the same ink in two layers, one configured for a coating as described in relation to layer 62A and one configured for a tactile layer as described in relation to layer 66, or, when printed using a suitable printing unit, in the form of a single layer in which the ink is deposited at different thicknesses in different regions, depending on whether the coating is required or a tactile characteristic is required.

[0252] For example, a hollow-engraving cylinder can be engraved to deposit an overall paper-like coating on a banknote in first regions and thicker tactile features in second regions. The cylinder can be either "double-engraved," for example, with a first engraving of the structures for the paper-like coating throughout the first and second regions, and then an engraving in the second regions only of deeper structures for the The tactile elements are deposited, either simply by etching the first regions for the paper-touch coating and the second regions for the tactile elements.

[0253] Regions in which only a paper touch is intended will have a first thickness corresponding to the thickness or weight of the coating chosen for the coating. For example, a suitable thickness in the first region is between 1.5 microns and 8 microns (ignoring any particle protrusions). Regions intended to be "tactile" elements, as described in relation to the tactile security feature below, may have a suitable thickness between 12 and 30 microns (although the thicker end of this range can only be achieved with certain ink technologies, such as UV, as will be described in more detail below).

[0254] Another embodiment of the coating described above has a different composition and ink system. In this embodiment, a radiation-curable resin system, such as a UV-curable ink or an electron-beam-curable ink, is used as the base resin. The weight percentage of paper-touch particles or fibrous conductive particles, when the ink is wet, does not change in a suitable composition. For example, a coating composition based on a suitable UV-curable ink is: • 73% UV-curable ink, such as SunCure® ink from Sun Chemical; • 12% of fibrous conductive particles, as described above; • 15% of particles to touch paper, as described above.

[0255] The composition can be modified, if necessary, by the addition of solvent, such as MEK, to obtain a viscosity of approximately 25 cP to 50 cP, but preferably 40 cP, or 23 seconds using a Zahn No. 2 cup. Alternatively, the composition can be heated to obtain the same viscosities.

[0256] It is well known that most UV-curable inks cannot provide good adhesion to polymeric substrates, such as BOPP, without some form of additional adhesion promoter. Suitable adhesion promoters include crosslinking agents such as isocyanates; polyaziridines; zirconium complexes; aluminum acetylacetone; melamines; and / or carbodiimides. A particularly suitable adhesion promoter is described in document WO1997027064. Furthermore, printing a solvent-based ink as a primer for a UV-curable ink, such as the composition above (with or without tactile and conductive particles), also serves as a suitable adhesion-promoting layer.

[0257] In particular, UV-based ink composition has a number of distinct advantages as indicated above in the "Banknote" section. In particular, UV-based coatings are especially resistant to wear.

[0258] Let us now refer to [Fig. 2B], which shows a 500 banknote having a substrate 520 and marking layers 560. The marking layers 560 may be multiple layers of the same color or of different colors. The substrate 500 may be any suitable substrate for printing a banknote, but the preferred substrate is a polymer and, in particular, an opacified polymer, having opacified particles in the mass of the substrate.

[0259] A tactile layer 620, having a composition as described above, is present on both sides of the substrate and has first regions 640 in a first thickness and second regions 650 in a second thickness. The first regions provide a "paper-like" feel to the surface of the banknote, and the second regions provide a tactile quality similar to that offered by Intaglio printing (as described in more detail in relation to the tactile security feature below). Importantly, this combination of tactile layers, offering two different types of tactile quality, can be printed in a single step, thereby reducing the number of printing units required and, consequently, the cost.

[0260] Solvent-based and UV-based coatings, whether used alone as a coating or as a combination of coating and tactile elements, offer additional advantages with regard to the wear of a banknote. In experimental tests, a TABER® Rotating Platform Abrasion Tester was used to measure wear resistance and is an intermediate step towards an accelerated wear test. More specifically, products with greater wear resistance would be more resistant to wear in real-world use and would last longer.

[0261] The results of the TABER® Abrasion Tester tests are recorded in the table below. [Tables 5] Banknote Description Number of cycles before defect Ink coating formulation Defect Description 2000 Indonesian Rupiah banknote (new, not in circulation, paper substrate printed in 2016). 60 Intaglio and Offset ink on a paper substrate. Intaglio and Offset ink worn down to the paper substrate in some areas (ink completely removed in approximately 50% of the area tested for wear). BOPP substrate - solvent-based coating (Test sample - newly printed). 550 Solvent-based inks for drawing layer, solvent-based tactile coating (from the composition described above to a cured thickness of 3 microns). All inks having the same polymeric chemical composition. Inks worn down to the polymer substrate in certain areas (ink completely removed in approximately 50% of the area tested for wear). BOPP substrate - UV-based coating (Test sample - newly printed).1420 Solvent-based inks for the drawing layer, solvent-based primer (of the composition described above but without particles, with a cured thickness of 1.5 microns). All solvent-based inks having the same chemical composition, the UV-based tactile layer (of the composition described above, with a cured thickness of 5 microns). Worn down to the substrate in some areas (ink completely removed in approximately 50% of the area tested for wear).

[0262] The above wear samples were left in the TABER® Abrasion Tester until they reached a condition that would typically necessitate the withdrawal of a banknote from circulation. The criteria in this case were that approximately 50% of the area subjected to the wear test no longer had ink in the drawing elements.

[0263] As can be seen from the results, the solvent-based coating has performance exceeding that of the paper substrate by more than 9 times and that of the UV-based coating by more than 23 times.

[0264] Although it may be possible to obtain different results for the wear resistance of a banknote based on a paper substrate and that of the sample used, it is clear that the coatings as described here offer significantly greater wear resistance than that offered by the tested paper banknote, and any variances in terms of paper substrate will be minimal. More specifically, even if a paper banknote were capable of performing twice as well as the one tested, it would quickly fall below the wear resistance of the coating described here. It should be noted that intaglio printing is typically in the range of 20 to 60 microns, and this thickness does not appear to enhance the wear resistance of the paper banknote.

[0265] However, it has been found that the coating thickness described here has some relationship with wear resistance and can be adjusted accordingly. Applying a thinner coating will reduce wear resistance, and applying a thicker coating will increase wear resistance. Since banknote defects can occur for other reasons, such as tearing, increasing wear resistance will result in fewer returns due to other types of defects. However, the coating thickness can be used to generate a predicted lifespan for the banknote by measuring the wear resistance of existing banknotes and adjusting the coating thickness to a chosen multiple of that wear resistance.

[0266] Touch security feature

[0267] As mentioned above, a printing layer 66 of [Fig. 2A] is a tactile printing layer. The tactile printing is carried out in the form of a chosen design and is an integral part of a tactile security feature. The tactile security feature provided is a pseudo-Intaglio feature. More specifically, Intaglio printing produces printing structures that are relatively deep (on the order of 20 to 150 microns) and has been used on banknotes for a considerable time, and the tactile security feature mimics this printing. The depth of the Intaglio printing structures creates a particular feel on a banknote that the public recognizes, due to the irregularity of Intaglio printing use.Therefore, if a banknote is to be created by another printing process, it is desirable to have a feature that presents a feel identical to an Intaglio print to the public.

[0268] In this embodiment, and with reference to Figures 4A, 4B and 4C, a tactile safety feature 80 is provided. The tactile safety feature 80 comprises a printed marking layer 82 and a printed enhanced tactile layer 84. Preferably, the marking layer 82 and the enhanced tactile layer 84 are both printed using the same printing process. Preferably, they are serially printed on a printing press, which is preferably an intaglio printing press, as illustrated in [Fig. 1A].

[0269] However, the tactile security feature as described herein is novel and inventive in itself, in that it provides an enhanced tactile feel to a design without requiring the use of intaglio printing to print that design. Further advantages are obtained when the security feature is applied within the same process, as it offers an alternative to the need for separate printing processes. This is of particular concern in the case of intaglio printing for banknotes, since it is usually necessary that the banknote sheets, after being intaglio printed, not be stacked at all, or be stacked with a minimum number of sheets, to allow time for the intaglio print to dry / cure.If this is not done, the height advantage of intaglio printing can be lost because the weight of the sheet stack distorts the intaglio print. Therefore, the minimum time between printing and handling is at least three days. Furthermore, most of the intaglio ink transfer is due to the pressure used to force this viscous ink out of the engravings. This pressure, reaching up to 10 tons / in², results in permanent embossing of the substrate. However, the polymer's modulus of elasticity is much higher than that of paper, and there is therefore a trade-off between tactility, ink quality, and handling issues, often at the expense of the polymer's tactile appeal.More specifically, embossing the substrate can cause process problems during additional steps that may be required to produce a banknote, such as numbering or the application of other security features or protective coatings.

[0270] The marking layer 82 is printed in one or more desired colors and in a desired pattern, which, in the case of [Fig. 4A], is the text "300". The enhanced tactile layer 84 is applied in a design or pattern as shown in [Fig. 4B], which, in this example, is a pattern of dots or circles, generally in the form of the text "300", overlapping / covering the design layer 82, as shown in [Fig. 4C]. The shape "300" is therefore an enhanced tactile area of ​​layer 84, the dots of which constitute a sub-area, which is printed on the underlying design of the marking layer 82. Although the preferred arrangement consists of While the enhanced touch layer at least completely overlaps the drawing layer, some designs may not require this overlap and may only require the enhanced touch layer to overlap the drawing layer in such a way that the enhanced touch layer partially covers the drawing layer.

[0271] The enhanced tactile layer 84 comprises a transparent ink or lacquer having a proportion of tactile particles added to the layer. The particles may be substantially spherical and have an average diameter of between 5 and 70 microns, but preferably 20 microns. Suitable spherical particles include those produced by Microchem under the Decosilk Art trademark, which are acrylic particles. Particles made of other materials, such as those indicated in connection with the paper tactile layer above, are also suitable for particles in the tactile layer.

[0272] However, the preferred particles are those described above in relation to the above coating, having a depth of 5 to 35 microns and an aspect ratio of about 1 to 5, comparing the depth to the widest point of the particle but preferably an average depth of 15 microns and an average aspect ratio of 3 and, preferably again, a particle having at least one dimension that is greater than 150% of the smallest dimension and otherwise as described above in relation to the coating.

[0273] To remove any doubt, the dots described in the tactile layer 84 do not represent individual particles, but rather each dot constitutes a dot of ink containing particles. Each dot therefore provides tactility, and the spacing between the dots enhances this tactility.

[0274] This combination of a marking layer and an enhanced tactile layer creates a security feature which, when handled, provides a feel analogous to that of the design layer having enhanced tactile quality and substantially analogous to the marking layer printed by a traditional intaglio process. In particular, it is not necessary for the enhanced tactile layer to be printed immediately on top of the marking layer; there may be other layers between them, as long as the marking layer remains clearly visible. However, it is preferable for the enhanced tactile layer to be the last layer printed on the banknote, as this provides the best tactile quality. In the context of the 50 banknote, it can be seen that the tactile layer 66 is printed after the coating 62A.

[0275] Therefore, it is preferable that the marking layer resemble traditional Intaglio printing styles, which are typically designs consisting of a series of lines, and sometimes known as intaglio engraving. In some cases, Intaglio printing styles include dots as well as lines. Therefore, An intaglio printing style is a representation made up of lines and dots, in a way that could be engraved into an intaglio printing plate. Therefore, the marking layer preferably includes a design made up of a series of lines and, possibly, dots.

[0276] Let us now refer to [Fig. 5A], which presents a marking, or design element, printed in the traditional Intaglio style. The marking is a representation of the statue of Menelaus, from the marble sculpture "Menelaus Supporting the Body of Patroclus," in the Loggia dei Lanzi, Florence, Italy. As can be seen, the features of Menelaus's head have been recreated through the use of lines and dots, which could be used, if desired, to create an Intaglio printing plate.

[0277] Instead, design 90 is used as a basis for creating an engraving on an intaglio cylinder to create a marking layer in a security document, preferably a banknote. To be printable by an intaglio cylinder, design 90 is converted in a known manner into a suitable cellular structure design, which is then mechanically / chemically engraved onto a suitable cylinder. The cylinder is then used in an intaglio printing press to print the design onto a suitable substrate.

[0278] As shown in [Fig. 5B], a design of an enhanced tactile layer 92 is then generated, which generally has ends that are no larger than the ends of the marking 90. The design of the enhanced tactile layer 92 comprises a series of wavy vertical lines 94 and a series of design features 96. In this example, the design features 96 are representative of the face and helmet, which are components of the design 90. The design of the enhanced tactile layer 92 is then used to create an intaglio printing cylinder, in a manner similar to that described above for the marking 90, but taking into account that the ink will contain particles, to create an enhanced tactile layer in the same security material as the marking 90.For example, one method of taking particles into account involves creating cells on the hollow etching cylinder that are large enough to retain one or more particles.

[0279] The marking 90 and the enhanced tactile layer 92 are printed in register, as shown in [Fig. 5C]. The term "printed in register" is a technical term from the field of printing and, in this case, simply means that the enhanced tactile layer sufficiently covers the drawing layer so that a user associates the tactile layer with the drawing layer.

[0280] It will be understood that the enhanced tactile layer is preferably transparent. However, it is possible to use an enhanced tactile layer that is translucent, not totally transparent, or coloured, as long as the marking layer 90 is visible to the extent required.

[0281] In this preferred example, the enhanced tactile layer is printed with a transparent ink / lacquer that contains tactile particles that do not affect the visibility of the marking 90. Figures 5B and 5C show the enhanced tactile layer 92 in black for better understanding and representation purposes only.

[0282] The tactile particles are, as briefly mentioned above in relation to [Fig.2A], preferably substantially spherical and have an average diameter of about 20 microns.

[0283] Appropriate particle sizes for this security feature have an average particle size of 5 to 70 microns, depending on the desired degree of roughness. The particles may be spherical or aspherical but must be of sufficient size in a relevant direction to provide variance to the ink surface in which the particle is deployed during printing. For example, if aspherical particles are used, such as wafer-like particles, then the particles tend to orient themselves with their longest dimension parallel to the surface being printed. As such, the relevant dimension of the wafer is its depth, which must be large enough to create a difference in depth compared to regions of the printed ink that do not contain particles.Suitable particles include platelet-type particles, having at least one dimension that is greater than 150% of the smallest dimension (usually the depth, as the printing process tends to naturally orient platelet-type particles in this way, as mentioned above).

[0284] Furthermore, another embodiment of this tactile safety feature includes the use of retroreflective, or semi-retroreflective, beads as tactile particles. The beads would be of the size indicated above, but have the safety characteristic that, when exposed to bright light, such as a camera flash, they reflect the bright light, saturating the reflection of the design on which the beads have been printed. As such, taking a photograph of the safety feature with a camera, mobile phone, or similar device results in a bright white area where the beads have been printed, which tends to obscure the printed design over which it is superimposed.This results in two distinct security aspects: firstly, a verification feature, which can be verified as a genuine security feature; and a feature resistant to the . copy, so that it is more difficult to electronically copy a banknote including such a tactile feature.

[0285] As indicated above, the tactile security feature described herein offers several advantages over traditional intaglio printing. In particular, it provides an equivalent tactile security feature that can be produced more quickly, as it does not require consideration of the distortion of the printed feature and does not require the printing step to be separated from other features to be printed. A particular advantage lies in the production of this feature by intaglio printing, which has a higher throughput than an intaglio printing press. As such, any substrate requiring such a tactile security feature is suitable, whether the substrate is paper, polymer, a paper / polymer hybrid, or another material.

[0286] Combination of the above embodiments

[0287] The above embodiments are described in context. However, each embodiment can be combined with one or more of the other embodiments. For example, a particularly advantageous banknote includes a combination of ink layers from a single ink system, a tactile security feature, and a coating, as described above.

[0288] As used in this document (including in the claims), the terms "include", "comprise", "included" or "comprising" shall be interpreted as specifying the presence of the features, integers, steps or components mentioned, but does not exclude the presence of one or more other features, integers, steps or components, or groups thereof.

[0289] It will be understood that the invention is not limited to the specific embodiments described in this document, which are provided by way of example only. The scope of the invention is as defined by the attached claims.

Claims

Demands

1. Substrate having a tactile security feature for a banknote, said tactile security feature having a marking layer printed on said substrate and including a design element and a printed enhanced tactile layer, which has at least one first enhanced tactile zone overlapping the design element, the design element being visible through the first enhanced tactile zone, such that the design element appears to have tactileity due to the overlap of the first enhanced tactile zone, the design element and the first enhanced tactile zone together forming the security feature, characterized in that the design element and the at least one first enhanced tactile zone are formed using the same serial printing process on a single printing press, wherein the enhanced tactile layer contains tactile particles.

2. Substrate having a tactile security feature according to claim 1, wherein the first area with enhanced tactileness and the drawing element are printed in register.

3. Substrate having a tactile safety feature according to claim 1 or 2, wherein the tactile particles have at least one dimension which has an average size of 5 to 70 microns.

4. Substrate having a tactile safety feature according to any one of claims 1 to 3, wherein the tactile particles have an average diameter of substantially 20 microns, and / or are spherical.

5. Substrate having a tactile safety feature according to any one of claims 1 to 4, wherein the tactile particles have a size of 5 to 35 microns in at least one dimension.

6. Substrate having a tactile safety feature according to any one of claims 1 to 5, wherein the tactile particles have an aspect ratio between substantially 1 and 5.

7. Substrate having a tactile safety feature according to any one of claims 1 to 6, wherein the tactile particles have, at least on average, a dimension in at least one direction that is greater than 150% of the smallest dimension.

8. Substrate having a tactile safety feature according to any one of claims 1 to 7, wherein the enhanced tactile layer is applied in a first thickness in first regions and a second thickness in second regions.

9. Substrate having a tactile safety feature according to any one of claims 1 to 8, wherein the printed marking layer has a print depth of 5 microns or less.

10. Banknote having a substrate with a tactile security feature according to any one of claims 1 to 9.

11. A method for producing a tactile security feature for a banknote, the method comprising the following steps: - supplying a substrate, - forming a design element on the substrate, and - forming at least one first enhanced tactile zone in a printed enhanced tactile layer, wherein the at least one enhanced tactile layer overlaps the design element, the design element being visible through the first enhanced tactile zone, characterized in that the design element and the at least one first enhanced tactile zone are formed using the same serial printing process on a single printing press and in that the enhanced tactile layer comprises tactile particles.

12. Method according to claim 11, wherein the first area with enhanced tactility and the drawing element are printed in register.

13. A method according to claim 11 or 12, wherein the tactile particles have at least one dimension which has an average size of 5 to 70 microns.

14. A method according to any one of claims 11 to 13, wherein the tactile particles have an average diameter of approximately 20 microns, and / or are spherical.

15. A method according to any one of claims 11 to 14, wherein the tactile particles have a size of 5 to 35 microns in at least one dimension.

16. A method according to any one of claims 11 to 15, wherein the tactile particles have an aspect ratio between substantially 1 and 5.

17. A method according to any one of claims 11 to 16, wherein the touch particles have, at least on average, a dimension in at least one direction that is greater than 150% of the smallest dimension of the touch particles.

18. A method according to any one of claims 11 to 17, wherein the improved tactility layer is applied in a first thickness in first regions and in a second thickness in second regions.

19. A method according to any one of claims 11 to 18, wherein the printed marking layer has a print depth of 5 microns or less.

20. A method according to any one of claims 11 to 19, wherein the design element and at least one first area with enhanced tactileness are printed using an intaglio printing press.

21. A method according to any one of claims 11 to 20, wherein the design element is a series of lines and / or points.

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