Method for producing an optical effect layer comprising magnetic or magnetizable pigment particles

Abstract

The present invention relates to the field of protection of security documents, such as banknotes and identity documents, against counterfeiting and illegal duplication. In particular, the present invention provides a method for producing an optical effect layer (OEL) exhibiting one or more indicia (x30) on a substrate (x20), the method comprising the steps of exposing a coating layer (x10) comprising non-spherical magnetic or magnetizable pigment particles to a magnetic field of a magnetic field generator in order to orient at least a portion of the non-spherical magnetic or magnetizable pigment particles, applying a top coating composition on the coating layer (x10) in the form of the one or more indicia (x30), and at least partially curing the coating layer (x10) and the one or more indicia (x30) in a curing device (x50).

Description

Field of the Invention

[0001]

[0001] The present invention relates to the field of magnetic field generating devices and methods for producing an optical effect layer (OEL) comprising magnetically oriented platelet-shaped magnetic or magnetizable pigment particles. In particular, the present invention relates to magnetic field generating devices and methods for magnetically orienting platelet-shaped magnetic or magnetizable pigment particles in a coating layer to produce an OEL, and to their use as an anti-counterfeiting means for security documents or security articles, as well as for the purpose of decorating said OEL. Background of the Invention

[0002]

[0002] For example, in the field of security documents, the use of inks, compositions, coatings, or layers comprising oriented magnetic or magnetizable pigment particles, in particular also optically variable magnetic or magnetizable pigment particles, for the production of security elements is known in the art. Coatings or layers comprising oriented magnetic or magnetizable pigment particles are disclosed, for example, in U.S. Patent No. 2,570,856; U.S. Patent No. 3,676,273; U.S. Patent No. 3,791,864; U.S. Patent No. 5,630,877, and U.S. Patent No. 5,364,689. Coatings or layers comprising oriented magnetic color-shifting pigment particles provide particularly attractive optical effects and are useful for the protection of security documents and are disclosed in International Publication No. 2002 / 090002 and International Publication No. 2005 / 002866.

[0003]

[0003] For example, security features for security documents can generally be classified into, on the one hand, "secret" security features and, on the other hand, "public" security features. The protection provided by secret security features depends on the principle that such features are difficult to detect, typically requiring specialized devices and knowledge for detection, while "public" security features rely on the concept that they can be easily detected by the human sense on its own. For example, such features are more difficult to fabricate and / or replicate while being visible and / or detectable by touch. However, the effectiveness of public security features significantly depends on their easy recognition as security features.

[0004]

[0004] Magnetic or magnetizable pigment particles in printing inks or coatings enable the creation of magnetically induced images, designs and / or patterns by the application of a correspondingly configured magnetic field, causing a local orientation of the magnetic or magnetizable pigment particles in the uncured (i.e., wet) coating, followed by curing of the coating. The result is a fixed and stable magnetically induced image, design, or pattern. Materials and techniques for the orientation of magnetic or magnetizable pigment particles in coating compositions are disclosed, for example, in U.S. Patent No. 2,418,479; U.S. Patent No. 2,570,856; U.S. Patent No. 3,791,864, German Patent Application Publication No. 2006848, U.S. Patent No. 3,676,273, U.S. Patent No. 5,364,689, U.S. Patent No. 6,103,361, European Patent No. 0406667; U.S. Patent Application Publication No. 2002 / 0160194; U.S. Patent Application Publication No. 2004 / 0009308; European Patent Application Publication No. 0710508; International Publication No. 2002 / 09002; International Publication No. 2003 / 000801; International Publication No. 2005 / 002866; International Publication No. 2006 / 061301. In such a way, magnetically induced patterns highly resistant to forgery can be created. The security element in question can only be created by accessing both the magnetic or magnetizable pigment particles or the corresponding pigment ink and the specific technique used to orient the pigment in the printed ink.

[0005]

[0005] For the purpose of protecting security documents or articles containing magnetic induction images from the premature and disadvantageous effects of the use of soil and / or moisture and time, a protective varnish is customarily applied. The protective varnish is applied as a continuous layer on a previously prepared dried / cured magnetic induction image.

[0006]

[0006] International Publication No. WO 2011 / 012520 discloses a transfer foil including a coating layer having a design form, the design including an oriented optically variable magnetic pigment representing an image, a mark, or a pattern. The transfer foil may further include a top coating layer, which is applied before the application of the layer including the optically variable magnetic pigment. The process for producing the transfer foil includes steps of: a) applying a top coating layer and hardening / curing the top coating layer; and b) applying a layer including an optically variable magnetic pigment, magnetically orienting the particles, and hardening / curing the layer. The disclosed method is not suitable for producing magnetic induction images necessary for indicating personal variable marks.

[0007]

[0007] European Patent Nos. EP 1641624, EP 1937415, and EP 2155498 disclose apparatuses and methods for magnetically transferring a mark to an uncured (i.e., wet) coating composition including magnetic or magnetizable pigment particles for forming an optical effect layer (OEL). The disclosed methods enable the production of security documents and articles having customer-specific magnetic designs. However, the disclosed magnetic devices are prepared to satisfy a customer-specific magnetic design and cannot be changed when the design needs to be changed from one article to another. Thus, the method is not suitable for producing the OEL necessary for indicating personal variable marks.

[0008]

[0008] European Patent No. 3170566, European Patent Application Publication No. 3459758, and European Patent No. 2542421 disclose different methods for producing variable markings on optically variable magnetic inks. However, the said methods require the use of special devices such as photomasks or lasers.

[0009]

[0009] For the purpose of providing variable information with magnetic properties on security documents or articles, inkjet inks containing magnetic particles have been developed to enable magnetic ink character recognition (MICR). However, the said inkjet inks face various problems, especially related to the shelf-life stability of the ink, ink printability, non-uniform magnetic ink deposits, and print head clogging. European Patent No. 2223976 discloses a method for producing documents containing MICR features, the said method including the steps of jetting a pattern of curable ink containing a gelling agent onto a substrate by inkjet, cooling the ink to a temperature below the gelling temperature of the ink, imparting a magnetic material to the ink, and finally curing the said ink. Alternatively, toners containing magnetic particles have also been developed, for example, as disclosed in U.S. Patent No. 10,503,091 and U.S. Patent No. 10,359,730. However, specific dedicated devices are required to print those toners.

[0010]

[0010] Therefore, there is a need for a method for generally producing a customized optical effect layer showing one or more markings on an industrial scale, the said optical effect layer showing a prominent effect. Further, the said method should be reliable, easy to implement, and capable of functioning at a high production speed.

Summary of the Invention

[0011]

[0011] Therefore, the present invention aims to overcome the deficiencies of the prior art. This is a method for producing an optical effect layer (OEL) showing one or more markings (x30) on a substrate (x20), a) Applying a radiation-curable coating composition containing non-spherical magnetic or magnetizable pigment particles onto the surface of a substrate (x20), wherein the radiation-curable coating composition is in a first liquid state for forming a coating layer (x10); b) Exposing the coating layer (x10) to the magnetic field of a magnetic field generating device to orient at least a part of the magnetic or magnetizable pigment particles; c) After step b), applying a top coating composition onto the coating layer (x10), wherein the top coating composition is applied in the form of one or more marks (x30); d) Achieved by providing a method comprising, at least partially simultaneously with or after step c), curing the coating layer (x10) and the one or more marks (x30) in a curing device (x50).

[0012]

[0012] In one preferred embodiment, step b) of exposing the coating layer (x10) is performed to orient at least a part of the magnetic or magnetizable pigment particles in a uniaxial direction. In another preferred embodiment, step b) of exposing the coating layer (x10) is performed to orient at least a part of the magnetic or magnetizable pigment particles in a biaxial direction.

[0013]

[0013] In one preferred embodiment, step a) of applying the radiation-curable coating composition is performed by a process selected from the group consisting of screen printing, gravure printing, pad printing, and flexographic printing.

[0014]

[0014] In one preferred embodiment, step c) of applying the top coating composition is performed by non-contact fluid microdispensing technology, preferably an inkjet printing process.

[0015]

[0015] Also described herein are an optical effect layer (OEL) and a security document produced by the method described herein, and a decorative element and an ornament comprising one or more optical OELs described herein.

[0016]

[0016] Also described is a method for manufacturing a security document, or a decorative element or an ornament, the method comprising: a) providing a security document, or a decorative element or an ornament; and b) providing an optical effect layer such as those described herein, in particular those obtained by the method described herein, which is included by the security document or the decorative element or the ornament.

[0017]

[0017] The method advantageously described herein uses two compositions which are applied to each other in a wet-on-wet state. In particular, the method according to the invention enables the production of an optical effect layer (OEL) showing one or more marks in a general way and can be easily implemented on an industrial scale at a high production speed. The two compositions used in the method described herein are, as a first composition, a radiation-curable coating composition applied onto a substrate (x20) containing non-spherical magnetic or magnetizable pigment particles, and, when the radiation-curable coating composition is still in a wet and unpolymerized state, a top-coating composition as a second composition which is applied onto the radiation-curable coating composition containing pigment particles, partially overlaps with the composition (i.e., overlaps in at least one area), and is applied in the form of one or more marks.

[0018]

[0018] The present invention provides a reliable and easy-to-implement method for creating a prominent optical effect layer (OEL) that exhibits one or more indicia described herein. The disclosed method advantageously enables, for each variable or personal indicium and for each customer-specific optical effect layer (OEL), the creation of security documents and articles having a customer-specific magnetic design that also exhibits one or more indicia in a versatile on-line variation, without requiring customization of the magnetic assemblies used to orient non-spherical magnetic or magnetizable pigment particles, in a method that is easy to implement and highly reliable. The present invention also provides a reliable and easy method for implementing a method for creating a prominent optical effect layer (OEL) that exhibits one or more indicia described herein, including variable halftones.

[0019]

[0019] The method described herein for creating an optical effect layer (OEL) that exhibits one or more indicia (x30) on a substrate (x20) described herein will be described in more detail below with reference to the drawings and specific embodiments.

Brief Description of the Drawings

[0020]

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Figure 5E

[0021] Definitions

[0020] The following definitions are used to interpret the meaning of the terms discussed in the detailed description and recited in the claims.

[0022]

[0021] As used herein, the term "at least one" is meant to define one or more, for example, 1, 2, or 3.

[0023]

[0022] As used herein, the terms "about" and "substantially" mean that the quantity or value in question is a specified particular value or some other value in the vicinity thereof. In general, the terms "about" and "substantially" when indicating a value are intended to indicate a range within ±5% of the value. As an example, the expression "about 100" indicates a range of 100 ± 5, that is, a range of 95 to 105. Generally, when the terms "about" and "substantially" are used, it can be expected that similar results or effects according to the present invention can be obtained within the range of ±5% of the indicated value.

[0024]

[0023] The term "substantially parallel" refers to deviating from a parallel arrangement by 10° or less, and the term "substantially perpendicular" refers to deviating from a perpendicular arrangement by 10° or less.

[0025]

[0024] As used herein, the term "and / or" means that all or only one of the elements of the group may be present. For example, "A and / or B" shall mean "only A, or only B, or both A and B". In the case of "only A", the term also includes the possibility that B is not present, that is, "only A and there is no B".

[0026]

[0025] As used herein, the term "comprising" is meant to be non-exclusive and non-limiting. Thus, for example, a coating composition comprising compound A may also contain other compounds in addition to A. However, the term "comprising" also encompasses, as specific embodiments thereof, the more limiting meanings of "consisting essentially of" and "consisting of", and as a result, for example, "moisture containing A, B, and optionally C" may also consist (substantially) of A and B, or (substantially) of A, B, and C.

[0027] As used herein, the term "optical effect layer" (OEL) represents a coating layer containing oriented magnetic or magnetizable pigment particles, said magnetic or magnetizable pigment particles being oriented by a magnetic field, and the oriented magnetic or magnetizable pigment particles being fixed / solidified in their orientation and position (i.e., after curing) to form a magneto - inductive image.

[0028] The term "coating composition" refers to any composition that can form an optical effect layer (OEL) on a solid substrate and can preferably be applied by a printing method, among others. The coating composition includes the platelet - shaped magnetic or magnetizable pigment particles described herein and the binder described herein.

[0029] As used herein, the term "wet" refers to an uncured coating layer, e.g., a coating layer in which platelet - shaped magnetic or magnetizable pigment particles can further change their position and orientation under the influence of an external force acting on them.

[0030] The term "security document" refers to a document that is normally protected from forgery or fraud by at least one security feature. Examples of security documents include, but are not limited to, value documents and value goods.

[0031] The term "security feature" is used to represent an image, pattern, or graphic element that can be used for authentication purposes.

[0032] When this detailed description refers to "preferred" embodiments / features, combinations of these "preferred" embodiments / features are also considered to be disclosed to the extent that the combination of these "preferred" embodiments / features is technically meaningful.

[0033]

[0032] The present invention provides a method for producing an optical effect layer (OEL) that exhibits one or more markings (x30) on a substrate (x20), said OEL being based on magnetically oriented platelet-shaped magnetic or magnetizable pigment particles and further exhibiting one or more markings (x30).

[0034]

[0033] The method described herein includes step a) of applying a radiation-curable coating composition comprising non-spherical magnetic or magnetizable pigment particles described herein onto the surface of the substrate (x20) described herein to form the coating layer (x10) described herein, said composition being in a first liquid state that enables its application as a layer and in which the pigment particles can move and rotate within the layer, i.e., an uncured (i.e., wet) state. Since the radiation-curable coating composition described herein is to be provided on the surface of the substrate (x20), the radiation-curable coating composition includes at least a binder material and magnetic or magnetizable pigment particles, and said composition is in a form that enables its processing with a desired printing or coating apparatus. Preferably, step a) is preferably selected from the group consisting of screen printing, gravure printing, flexographic printing, intaglio printing (also referred to in the art as engraved copper printing, engraved steel die printing), pad printing, and curtain coating, more preferably intaglio printing, screen printing, gravure printing, pad printing, and flexographic printing, and even more preferably is carried out by a printing process selected from the group consisting of screen printing, gravure printing, pad printing, and flexographic printing.

[0035]

[0034] The non-spherical magnetic or magnetizable pigment particles described herein are preferably magnetic or magnetizable pigment particles having an oblong or flattened ellipsoidal shape, a platelet shape, or a needle shape, or a mixture of two or more thereof, more preferably platelet-shaped particles.

[0036]

[0035] The non-spherical magnetic or magnetizable pigment particles described herein are defined as having an anisotropic reflectivity with respect to incident electromagnetic radiation for which the cured binder material is at least partially transparent due to their non-spherical shape. As used herein, the term "anisotropic reflectivity" means that the ratio of incident radiation from a first angle reflected by the particle to a (viewing) direction (second angle) is a function of the orientation of the particle, i.e., a change in the orientation of the particle with respect to the first angle can cause different magnitudes of reflection in the viewing direction. Preferably, the non-spherical magnetic or magnetizable pigment particles described herein have an anisotropic reflectivity with respect to incident electromagnetic radiation, at least in part, or in the complete wavelength range of from about 200 to about 2500 nm, more preferably from about 400 to about 700 nm, such that a change in the orientation of the particle results in a change in the reflection by that particle in a certain direction. As is known to those skilled in the art, the magnetic or magnetizable pigment particles described herein differ from the conventional pigments in that the conventional pigment particles exhibit the same color and reflectivity regardless of particle orientation, while the magnetic or magnetizable pigment particles described herein exhibit a reflection and / or color that depends on particle orientation, or both.

[0037]

[0036] For an embodiment of the method described herein, step b) or b1) of exposing the coating layer (x10) to the magnetic field of the magnetic field generating device described herein is carried out to orient at least a portion of the magnetic or magnetizable pigment particles in a biaxial direction, and at least a portion of the non-spherical magnetic or magnetizable pigment particles described herein need to consist of platelet-shaped magnetic or magnetizable pigment particles having an X-axis and a Y-axis that define the major plane of extension of the particles. In contrast to needle-shaped pigment particles that can be considered one-dimensional particles, platelet-shaped pigment particles have an X-axis and a Y-axis that define the major plane of extension of the particles. In other words, platelet-shaped pigment particles may be considered two-dimensional particles due to the large aspect ratio of their dimensions, as can be understood from FIG. 1. As shown in FIG. 1, platelet-shaped pigment particles can be considered to have a two-dimensional structure in which dimensions X and Y are substantially larger than dimension Z. Platelet-shaped pigment particles are also referred to in the art as elliptical particles or flakes. Such pigment particles can be described by a major axis X corresponding to the longest dimension across the pigment particle and a second axis Y perpendicular to X that is also located within the pigment particle.

[0038]

[0037] The method described herein includes step b) of exposing the coating layer (x10) to the magnetic field of the magnetic field generating device described herein to orient at least a portion of the magnetic or magnetizable pigment particles. According to one embodiment, step b) is carried out to orient at least a portion of the magnetic or magnetizable pigment particles described herein in a uniaxial direction. According to another embodiment, step b) is carried out to orient at least a portion of the platelet-shaped magnetic or magnetizable pigment particles in a biaxial direction, preferably to orient at least a portion of the platelet-shaped magnetic or magnetizable pigment particles in a biaxial direction such that both their X-axis and Y-axis are substantially parallel to the substrate surface. For embodiments in which the method described herein includes the step of exposing the coating layer (x10) to the magnetic field of the magnetic field generating device described herein to orient at least a portion of the magnetic or magnetizable pigment particles in a biaxial direction, the coating layer (x10) may be exposed to the magnetic field generating device more than once.

[0039]

[0038] During the magnetic orientation (step b) of the magnetic or magnetizable pigment particles described herein, the substrate (x20) supporting the coating layer (x10) can be disposed on a non-magnetic support plate (x40) made of one or more non-magnetic materials.

[0040]

[0039] During the magnetic orientation (step b) of the magnetic or magnetizable pigment particles described herein, the position of the magnetic field generating device is not limited and depends on the selection and design of the magnetic orientation pattern to be produced. Thus, the positions of the magnetic field generating devices (B1, B2, B3) in FIGS. 2 and 4 are for illustrative purposes only and are not limiting. Depending on the selection and design of the magnetic orientation pattern to be produced, the magnetic field generating devices (B1, B2, B3) in FIGS. 2 and 4 can be located under the substrate (x20) or on the coating layer (x10).

[0041]

[0040] In contrast to uniaxial orientation in which magnetic or magnetizable pigment particles are oriented such that only their major axes are restrained by a magnetic field, performing biaxial orientation means that platelet-shaped magnetic or magnetizable pigment particles are oriented such that their two major axes are restrained. That is, each of the platelet-shaped magnetic or magnetizable pigment particles can be considered to have a major axis in the plane of the pigment particle and a minor axis orthogonal to the plane of the pigment particle. The major axis and minor axis of the platelet-shaped magnetic or magnetizable pigment particles are each oriented according to the magnetic field. Effectively, this results in platelet-shaped magnetic pigment particles that are adjacent to each other with a gap therebetween and substantially parallel to each other. In other words, biaxial orientation aligns the planes of the platelet-shaped magnetic or magnetizable pigment particles such that the planes of the pigment particles are oriented substantially parallel to the planes of the adjacent (in all directions) platelet-shaped magnetic or magnetizable pigment particles. The magnetic field generating devices and methods described herein enable the platelet-shaped magnetic or magnetizable pigment particles described herein to be oriented in a biaxial direction such that they form a sheet-like structure having their X and Y axes preferably substantially parallel to the surface of the substrate (x20) and are flattened in the two dimensions.

[0042]

[0041] The magnetic field generating devices suitable for orienting the magnetic or magnetizable pigment particles described in this specification in a uniaxial direction are not limited, and examples include dipole magnets, quadrupole magnets, and combinations thereof. The following devices are provided herein as examples.

[0043]

[0042] An optical effect known as the flip-flop effect (also referred to as the switch effect in the art) includes a first printed portion and a second printed portion separated by a transition portion, and the pigment particles are aligned parallel to a first surface in the first portion, and the pigment particles in the second portion are aligned parallel to a second surface. The methods and magnets that bring about the effect are disclosed, for example, in US Patent Application Publication No. 2005 / 0106367 and European Patent No. 1819525.

[0044]

[0043] An optical effect known as the rolling bar effect as disclosed in US Patent Application Publication No. 2005 / 0106367 may also be brought about. The "rolling bar" effect is based on the orientation of pigment particles that mimic a curved surface across a coating. The observer sees a specular reflection zone that moves away from or towards the observer when the image is tilted. The pigment particles are curved and aligned, following a convex curved surface (also referred to as a negative curved surface orientation in this technology) or a concave curved surface (also referred to as a positive curved surface orientation in this technology). The methods and magnets that bring about the effect are disclosed, for example, in European Patent Application Publication No. 2263806, European Patent No. 1674282, European Patent Application Publication No. 2263807, International Publication No. 2004 / 007095, International Publication No. 2012 / 104098, and International Publication No. 2014 / 198905.

[0045] An optical effect known as the Venetian blind effect may also be provided. The Venetian blind effect includes pigment particles that are oriented to provide visibility to the underlying substrate surface along a specific direction of observation such that markings or other features present on or in the substrate surface become visible to an observer while obstructing visibility along other directions of observation. Methods and magnets for providing said effect are disclosed, for example, in US Patent No. 8,025,952 and European Patent No. 1819525.

[0046] An optical effect known as the moving ring effect may also be provided. The moving ring effect consists of an optical illusion image of an object such as a bell, cone, bowl, circle, ellipse, and hemisphere that appears to move in any x-y direction depending on the tilt angle of the optical effect layer. Methods and magnets for providing said effect are disclosed, for example, in European Patent Application Publication No. 1710756, US Patent No. 8,343,615, European Patent Application Publication No. 2306222, European Patent Application Publication No. 2325677, International Publication No. 2011 / 092502, US Patent Application Publication No. 2013 / 084411, International Publication No. 2014 / 108404, and International Publication No. 2014 / 108303.

[0047] An optical effect may also be provided that provides the optical impression of a pattern of light and dark areas that move when the effect is tilted. Methods and magnets for providing said effect are disclosed, for example, in International Publication No. 2013 / 167425.

[0048] An optical effect may also be provided that provides the optical impression of a loop-shaped body whose size changes when the effect is tilted. Methods and magnets for providing these optical effects are disclosed, for example, in International Publication No. 2017 / 064052, International Publication No. 2017 / 080698, and International Publication No. 2017 / 148789.

[0049] When the optical effect layer is tilted, an optical impression of one or more loop-shaped bodies whose shape changes may also be provided. The method and magnet for providing said effect are disclosed, for example, in International Publication No. WO 2018 / 054819.

[0050] An optical effect that provides an optical impression of a crescent moon that moves and rotates when tilted may also be provided. The method and magnet for providing said effect are disclosed, for example, in International Publication No. WO 2019 / 215148.

[0051] An optical effect that provides an optical impression of a loop-shaped body whose size and shape change when tilted may be provided. The method and magnet for providing said effect are disclosed, for example, in International Publication No. WO 2020 / 052862 of a concurrently filed PCT patent application.

[0052] An optical effect that provides an optical impression of an orthoscopic parallax effect, i.e., in this case, a bright reflective vertical bar that moves vertically when the substrate is tilted around the horizontal / latitude axis or moves in the horizontal / latitude direction when the substrate is tilted around the longitudinal axis, may be provided. The method and magnet for providing said effect are disclosed, for example, in International Application No. PCT / EP2020 / 052265 of a concurrently filed PCT patent application.

[0053] An optical effect that provides an optical impression of one loop-shaped body surrounded by one or more loop-shaped bodies may be provided, and the one or more loop-shaped bodies change their shape and / or their brightness when tilted. The method and magnet for providing said effect are disclosed, for example, in International Application No. PCT / EP2020 / 054042 of a concurrently filed PCT patent application.

[0054] When the substrate is tilted about the vertical / longitudinal axis, an optical effect may be provided that not only moves and / or appears and / or disappears in an oblique direction, but also provides an optical impression of a plurality of dark spots and a plurality of bright spots that move and / or appear and / or disappear in an oblique direction when the substrate is tilted. The method and magnet for providing said effect are disclosed, for example, in the co-pending European patent applications EP19205715.6 and European patent application 19205716.4.

[0055]

[0054] The magnetic field generating device described herein may be at least partially embedded in a non-magnetic support matrix made of one or more non-magnetic materials.

[0056]

[0055] The non-magnetic support plate (x40) described in this specification and the non-magnetic material of the non-magnetic support matrix described in this specification are preferably independently selected from the group consisting of non-magnetic metals and engineering plastics and polymers. Non-magnetic metals include, but are not limited to, aluminum, aluminum alloys, brass (an alloy of copper and zinc), titanium, titanium alloys, and austenitic steel (i.e., non-magnetic steel). Engineering plastics and polymers include, but are not limited to, polyaryl ether ketone (PAEK) and its derivatives, polyether ether ketone (PEEK), polyether ketone ketone (PEKK), polyether ether ketone ketone (PEEKK), and polyether ketone ether ketone ketone (PEKEKK); polyacetal, polyamide, polyester, polyether, copolyether ester, polyimide, polyetherimide, high density polyethylene (HDPE), ultra-high molecular weight polyethylene (UHMWPE), polybutylene terephthalate (PBT), polypropylene, acrylonitrile butadiene styrene (ABS) copolymer, fluorinated and perfluorinated polyethylene, polystyrene, polycarbonate, polyphenylene sulfide (PPS), and liquid crystal polymer. Preferred materials are PEEK (polyether ether ketone), POM (polyoxymethylene), PTFE (polytetrafluoroethylene), nylon (registered trademark) (polyamide), and PPS.

[0057]

[0056] The magnetic field generating device described in this specification may include a magnetic plate that supports one or more reliefs, imprints, or cuts. International Publication No. WO 2005 / 002866 and International Publication No. WO 2008 / 046702 are examples of such imprinted magnetic plates.

[0058]

[0057] The magnetic field generating device suitable for orienting the small plate-shaped magnetic or magnetizable pigment particles described in this specification in the biaxial direction is not limited.

[0059]

[0058] A particularly preferred apparatus for orienting pigment particles in two axial directions is disclosed in European Patent Application Publication No. 2157141. In the operation of a substrate supporting a coating layer containing pigment particles, the apparatus disclosed in European Patent Application Publication No. 2157141 provides a dynamic magnetic field that changes its direction to rapidly vibrate the pigment particles until both of the main axes (X-axis and Y-axis) are substantially parallel to the substrate surface, that is, the pigment particles rotate until they form a stable sheet-like formation with their X and Y axes substantially parallel to the substrate surface and are flattened in the two dimensions.

[0060]

[0059] Another particularly preferred apparatus for orienting pigment particles in two axial directions includes a linear permanent magnet Halbach array, that is, an apparatus including a plurality of magnets and a cylinder device having different magnetization directions. A detailed description of the Halbach permanent magnet is given by Z.Q. Zhu and D. Howe (Halbach permanent magnet machines and applications: a review, IEE.Proc.Electric Power Appl, 2001, 148, pp. 299-308). The magnetic field provided by such a Halbach array has the characteristic that it is concentrated on one side while being weakened to almost 0 on the other side. The linear Halbach array is disclosed, for example, in International Publication No. 2015 / 086257 and International Publication No. 2018 / 019594, and the Halbach cylinder device is disclosed in European Patent No. 3224055.

[0061]

[0060] Another particularly preferred apparatus for orienting pigment particles in two axial directions is a rotating magnet, said magnet comprising a disc-shaped rotating magnet or a magnetic field generating device that is substantially magnetized along their diameter. Suitable rotating magnets or magnetic field generating devices are described in US Patent Application Publication No. 2007 / 0172261, said rotating magnet or magnetic field generating device generating a radially symmetric time-varying magnetic field and enabling double orientation of magnetic or magnetizable pigment particles in an uncured coating composition. These magnets or magnetic field generating devices are driven by a shaft (or spindle) connected to an external motor. Chinese Patent No. 102529326 discloses an example of an apparatus comprising a rotating magnet that would be suitable for orienting magnetic or magnetizable pigment particles in two axial directions. In a preferred embodiment, the apparatus suitable for orienting magnetic or magnetizable pigment particles in two axial directions is a disc-shaped rotating magnet or magnetic field generating device without a shaft suppressed in a housing made of a non-magnetic, preferably non-conductive material, and is driven by one or more magnet wire coils wound around the housing. Examples of such disc-shaped rotating magnets or magnetic field generating devices without a shaft are disclosed in International Publication No. 2015 / 082344, International Publication No. 2016 / 026896, and International Publication No. 2018 / 141547.

[0062]

[0061] Another particularly preferred apparatus for orienting pigment particles in two axial directions is shown in Figure 3 and comprises a) at least a first set (S1) and a second set (S2), each of the first and second sets (S1, S2) comprising a first rod-shaped dipole magnet having a magnetic axis oriented substantially parallel to the substrate during magnetic orientation and two second rod-shaped dipole magnets having magnetic axes oriented substantially perpendicular to the substrate, and b) a pair (P1) of third rod-shaped dipole magnets having magnetic axes oriented substantially parallel to the substrate, such as those disclosed in co-pending European Patent Application No. EP20176506.2.

[0063]

[0062] The radiation-curable coating composition described herein and the coating layer (x10) described herein contain the non-spherical, preferably platelet-shaped magnetic or magnetizable pigment particles described herein, preferably in an amount of about 5 wt% to about 40 wt%, more preferably 10 wt% to about 30 wt%, and the weight ratio is based on the total weight of the radiation-curable coating composition or the coating layer (x10).

[0064]

[0063] In the OELs described herein, the magnetic or magnetizable pigment particles described herein are dispersed in a radiation-curable coating composition comprising a cured binder material that fixes the orientation and position of the magnetic or magnetizable pigment particles. The binder material is at least in a cured or solid state (also referred to herein as the second state) and is at least partially transmissive to electromagnetic radiation in the wavelength range of 200 nm to 3500 nm, i.e., the wavelength range typically referred to as the "optical spectrum" and including the infrared, visible, and UV portions of the electromagnetic spectrum. Thus, the particles contained in the cured or solid binder material and their orientation-dependent reflectance can be recognized through the binder material at some wavelengths within this range. Preferably, the cured binder material is at least partially transmissive to electromagnetic radiation in the wavelength range of 200 nm to 800 nm, more preferably 400 nm to 700 nm. As used herein, the term "transmissive" means that the transmission of electromagnetic radiation through a 20 μm layer of the cured binder material present in the OEL (not including small platelet-shaped magnetic or magnetizable pigment particles, but including all other optional components of the OEL if such components are present) is at least 50%, more preferably at least 60%, even more preferably at least 70% at the relevant wavelength. This can be determined by measuring the transmittance of a test piece of the cured binder material (without non-spherical magnetic or magnetizable pigment particles) according to a well-established test method, for example, DIN 5036-3 (1979-11). If the OEL functions as a security feature, then typically, technical means are required to detect the (completed) optical effect produced by the OEL under each illumination condition including the selected non-visible wavelength, and the detection requires that the wavelength of the incident radiation be selected outside the visible range, for example, in the near-UV range.

[0065]

[0064] Suitable examples of the non-spherical, preferably small platelet-shaped magnetic or magnetizable pigment particles described in this specification include, but are not limited to, magnetic metals selected from the group consisting of cobalt (Co), iron (Fe), and nickel (Ni); magnetic alloys of iron, manganese, cobalt, nickel, or mixtures of two or more thereof; magnetic oxides of chromium, manganese, cobalt, iron, nickel, or mixtures of two or more thereof; or pigment particles containing mixtures of two or more thereof. The term "magnetic" with respect to metals, alloys, and oxides refers to ferromagnetic or ferrimagnetic metals, alloys, and oxides. The magnetic oxides of chromium, manganese, cobalt, iron, nickel, or mixtures of two or more thereof may be pure or mixed oxides. Examples of magnetic oxides include, but are not limited to, iron oxides such as hematite (Fe2O3), magnetite (Fe3O4), chromium dioxide (CrO2), magnetic ferrite (MFe2O4), magnetic spinel (MR2O4), magnetic hexaferrite (MFe 12 O 19 ), magnetic orthoferrite (RFeO3), magnetic garnet M3R2(AO4)3, etc., where M represents a divalent metal, R represents a trivalent metal, and A represents a tetravalent metal.

[0066]

[0065] Examples of the non-spherical, preferably platelet-shaped magnetic or magnetizable pigment particles described in this specification include, but are not limited to, magnetic metals such as cobalt (Co), iron (Fe), or nickel (Ni); and pigment particles containing a magnetic layer M composed of one or more of magnetic alloys of iron, cobalt, or nickel. The magnetic or magnetizable pigment particles may be of a multilayer structure including one or more additional layers. Preferably, the one or more additional layers are one or more selected from the group consisting of metal fluorides such as magnesium fluoride (MgF2), silicon monoxide (SiO), silicon dioxide (SiO2), titanium dioxide (TiO2), and aluminum oxide (Al2O3), more preferably a layer A independently composed of silicon dioxide (SiO2); or one or more selected from the group consisting of metals and metal alloys, preferably selected from the group consisting of reflective metals and reflective alloys, more preferably one or more selected from the group consisting of aluminum (Al), chromium (Cr), and nickel (Ni), even more preferably a layer B independently composed of aluminum (Al); or a combination of one or more layer A such as the above and one or more layer B such as the above. Representative examples of the platelet-shaped magnetic or magnetizable pigment particles of the above multilayer structure include, but are not limited to, A / M multilayer structure, A / M / A multilayer structure, A / M / B multilayer structure, A / B / M / A multilayer structure, A / B / M / B multilayer structure, A / B / M / B / A / multilayer structure, B / M multilayer structure, B / M / B multilayer structure, B / A / M / A multilayer structure, B / A / M / B multilayer structure, B / A / M / B / A / multilayer structure, and the layer A, magnetic layer M, and layer B are selected from the above.

[0067]

[0066] The radiation-curable coating composition described herein may contain non-spherical, preferably platelet-shaped, optically variable magnetic or magnetizable pigment particles and / or non-spherical, preferably platelet-shaped, magnetic or magnetizable pigment particles having no optically variable properties. Preferably, at least a portion of the magnetic or magnetizable pigment particles described herein is composed of non-spherical, preferably platelet-shaped, optically variable magnetic or magnetizable pigment particles. In addition to the overt security provided by the color shift properties of the optically variable magnetic or magnetizable pigment particles, which enables the inks, coating compositions, or articles or security documents supporting coating layers containing the optically variable magnetic or magnetizable pigment particles described herein to be easily detected, recognized, and / or distinguished from their possible forgeries using the unaided human senses, the optical properties of the optically variable magnetic or magnetizable pigment particles may also be used as machine-readable tools for the recognition of OELs. Thus, the optical properties of the optically variable magnetic or magnetizable pigment particles are simultaneously used as secret or semi-secret security features in an authentication process in which the optical (e.g., spectral) properties of the pigment particles are analyzed, and thus the forgery resistance can be improved.

[0068]

[0067] The use of non-spherical, preferably platelet-shaped, optically variable magnetic or magnetizable pigment particles in the coating layer for producing OELs enhances the significance of OELs as security features for security document applications because such materials are secured in the security document printing industry and are not generally commercially available.

[0069]

[0068] As described above, preferably, at least a portion of the non-spherical, preferably platelet-shaped, magnetic or magnetizable pigment particles is composed of non-spherical, preferably platelet-shaped, optically variable magnetic or magnetizable pigment particles. These are preferably selected from the group consisting of magnetic thin film interference pigment particles, magnetic cholesteric liquid crystal pigment particles, interference coating pigment particles containing magnetic materials and mixtures of two or more thereof.

[0070] [

[0069] ]Magnetic thin film interference pigment particles are known to those skilled in the art and are disclosed, for example, in U.S. Patent No. 4,838,648; International Publication No. 2002 / 073250; European Patent No. 0686675; International Publication No. 2003 / 000801; U.S. Patent No. 6,838,166; International Publication No. 2007 / 131833; European Patent No. 2402401; International Publication No. 2019 / 103937; International Publication No. 2020 / 006286, and the documents cited therein. Preferably, the magnetic thin film interference pigment particles include pigment particles having a 5-layer Fabry-Perot multilayer structure, and / or pigment particles having a 6-layer Fabry-Perot multilayer structure, and / or pigment particles having a 7-layer Fabry-Perot multilayer structure, and / or pigment particles having a multilayer structure combining one or more multilayer Fabry-Perot structures.

[0071] [

[0070] ]A preferred 5-layer Fabry-Perot multilayer structure consists of a multilayer structure of absorber / dielectric / reflector / dielectric / absorber, and the reflector and / or absorber is also a magnetic layer. Preferably, the reflector and / or absorber is a magnetic layer containing nickel, iron, and / or cobalt, and / or a magnetic alloy containing nickel, iron, and / or cobalt, and / or a magnetic oxide containing nickel (Ni), iron (Fe), and / or cobalt (Co).

[0072] [

[0071] ]A preferred 6-layer Fabry-Perot multilayer structure consists of a multilayer structure of absorber / dielectric / reflector / magnetic / dielectric / absorber.

[0073] [

[0072] ]A preferred 7-layer Fabry-Perot multilayer structure consists of a multilayer structure of absorber / dielectric / reflector / magnetic / reflector / dielectric / absorber, such as disclosed in U.S. Patent No. 4,838,648.

[0074] Preferred pigment particles having a multilayer structure combining one or more Fabry - Pérot structures are those described in WO 2019 / 103937, consisting of a combination of at least two Fabry - Pérot structures, wherein the two Fabry - Pérot structures independently include a reflector layer, a dielectric layer, and an absorber layer, and the reflector and / or absorber layer can each independently include one or more magnetic materials, and / or the magnetic layer is a sandwich between the two structures. WO 2020 / 006 / 286 and EP 3587500 disclose even more preferred pigment particles having a multilayer structure.

[0075]

[0074] Preferably, the reflector layer described in this specification is selected from the group consisting of metals and metal alloys, preferably selected from the group consisting of reflective metals and reflective metal alloys, more preferably selected from the group consisting of aluminum (Al), silver (Ag), copper (Cu), gold (Au), platinum (Pt), tin (Sn), titanium (Ti), palladium (Pd), rhodium (Rh), niobium (Nb), chromium (Cr), nickel (Ni), and their alloys, even more preferably independently selected from one or more of the group consisting of aluminum (Al), chromium (Cr), nickel (Ni), and their alloys, and even more preferably independently consisting of aluminum (Al). Preferably, the dielectric layer is selected from the group consisting of metal fluorides such as magnesium fluoride (MgF2), aluminum fluoride (AlF3), cerium fluoride (CeF3), lanthanum fluoride (LaF3), sodium aluminum fluoride (e.g., Na3AlF6), neodymium fluoride (NdF3), samarium fluoride (SmF3), barium fluoride (BaF2), calcium fluoride (CaF2), lithium fluoride (LiF), and metal oxides such as silicon monoxide (SiO), silicon dioxide (SiO2), titanium dioxide (TiO2), aluminum oxide (Al2O3), more preferably independently selected from one or more independently selected from the group consisting of magnesium fluoride (MgF2) and silicon dioxide (SiO2), and even more preferably independently consisting of magnesium fluoride (MgF2). Preferably, the absorber layer is selected from the group consisting of aluminum (Al), silver (Ag), copper (Cu), palladium (Pd), platinum (Pt), titanium (Ti), vanadium (V), iron (Fe), tin (Sn), tungsten (W), molybdenum (Mo), rhodium (Rh), niobium (Nb), chromium (Cr), nickel (Ni), their metal oxides, their metal sulfides, their metal carbides, and their metal alloys, more preferably selected from the group consisting of chromium (Cr), nickel (Ni), their metal oxides, and their metal alloys, even more preferably independently selected from one or more of the group consisting of chromium (Cr), nickel (Ni), and their alloys.Preferably, the magnetic layer includes nickel (Ni), iron (Fe), and / or cobalt (Co); and / or a magnetic alloy containing nickel (Ni), iron (Fe), and / or cobalt (Co); and / or a magnetic oxide containing nickel (Ni), iron (Fe), and / or cobalt (Co). When magnetic thin-film interference pigment particles including a 7-layer Fabry-Perot structure are preferred, it is particularly preferred that the magnetic thin-film interference pigment particles include a 7-layer Fabry-Perot absorber / dielectric / reflector / magnetic body / reflector / dielectric / absorber multilayer structure composed of a Cr / MgF2 / Al / Ni / Al / MgF2 / Cr multilayer structure.

[0076]

[0075] The magnetic thin-film interference pigment particles described herein are considered to be safe for human health and the environment. For example, they may be multilayer pigment particles based on a 5-layer Fabry-Perot multilayer structure, a 6-layer Fabry-Perot multilayer structure, and a 7-layer Fabry-Perot multilayer structure. The pigment particles include one or more magnetic layers including a magnetic alloy having a composition substantially free of nickel and containing about 40 wt% to about 90 wt% iron, about 10 wt% to about 50 wt% chromium, and about 0 wt% to about 30 wt% aluminum. Representative examples of multilayer pigment particles considered to be safe for human health and the environment can be found in European Patent No. 2402401, and the entire content of this description is incorporated herein by reference.

[0077]

[0076] Suitable magnetic cholesteric liquid crystal pigment particles exhibiting optical variable properties include, but are not limited to, magnetic monolayer cholesteric liquid crystal pigment particles and magnetic multilayer cholesteric liquid crystal pigment particles. Such pigment particles are disclosed, for example, in International Publication No. 2006 / 063926, U.S. Patent No. 6,582,781, and U.S. Patent No. 6,531,221. International Publication No. 2006 / 063926 discloses monolayers and pigment particles obtained therefrom, having high brightness and color shift properties, and further specific properties such as magneto - adhesion. The disclosed monolayers and pigment particles are obtained therefrom by grinding the monolayers and comprise a three - dimensionally cross - linked cholesteric liquid crystal mixture and magnetic nanoparticles. U.S. Patent No. 6,582,781 and U.S. Patent No. 6,410,130 disclose platelet - shaped cholesteric multilayer pigment particles containing sequence A 1 / B / A 2 wherein A 1 and A 2 may be the same or different, each comprising at least one cholesteric layer, and B is an intermediate layer that absorbs all or part of the light transmitted by layers A1 and A2 and imparts magnetic properties to the intermediate layer. U.S. Patent No. 6,531,221 discloses platelet - shaped cholesteric multilayer pigment particles containing sequence A / B, and optionally C, wherein A and C are absorption layers containing pigment particles that impart magnetic properties, and B is a cholesteric layer.

[0078]

[0077] Suitable interference coating pigments containing one or more magnetic materials include, but are not limited to, structures composed of substrates selected from the group consisting of cores coated with one or more layers, wherein at least one or one or more layers of the core have magnetic properties. For example, a suitable interference coating pigment includes a core made of a magnetic material such as those described above, the core being coated with one or more layers made of one or more metal oxides, or they have a structure composed of a core made of synthetic or natural mica, layered silicates (e.g., talc, kaolin, and sericite), glass (e.g., borosilicate), silicon dioxide (SiO2), aluminum oxide (Al2O3), titanium dioxide (TiO2), graphite, and mixtures of two or more thereof. Further, one or more additional layers such as a coloring layer may be present.

[0079]

[0078] The non-spherical, preferably platelet-shaped magnetic or magnetizable pigment particles described herein preferably have a size d50 (measured by direct optical particle size distribution) of from about 2 μm to about 50 μm.

[0080]

[0079] The non-spherical, preferably platelet-shaped magnetic or magnetizable pigment particles described herein may have a surface that has been treated to protect them from degradation that can occur in the coating composition and coating layer and / or to facilitate their incorporation into the coating composition and coating layer, and typically, corrosion inhibitors and / or wetting agents may be used.

[0081] As described herein, the methods described herein include step d) of at least partially curing the coating layer (x10) to fix magnetic or magnetizable pigment particles in their employed positions and orientations. In the first liquid state of the radiation curable coating composition, the magnetic or magnetizable pigment particles can move and rotate, and in the second state, the magnetic or magnetizable pigment particles are fixed and provided by using a certain type of radiation curable coating composition. For example, the components of the radiation curable coating composition other than non-spherical magnetic or magnetizable pigment particles may be in the form of inks or radiation curable coating compositions such as those used in security applications, for example, in the printing of banknotes. The aforementioned first and second states are brought about by using a material that exhibits an increase in viscosity in response to exposure to electromagnetic radiation. That is, when the fluid binder material is cured or solidified, the binder material changes to the second state, and the non-spherical magnetic or magnetizable pigment particles are fixed in their current positions and orientations and can no longer move or rotate within the binder material. As used herein, "at least partially curing the coating layer (x10)" means that non-spherical, preferably platelet-shaped magnetic or magnetizable pigment particles are fixed / solidified in their employed positions and orientations and can no longer move or rotate (also referred to as "pinning" the particles in the art).

[0082]

[0081] The radiation-curable coating composition used to produce the coating layer (x10) described herein comprises non-spherical, preferably platelet-shaped magnetic or magnetizable pigment particles described herein. Radiation curing, particularly UV-Vis curing, advantageously results in an immediate increase in the viscosity of the coating composition after exposure to irradiation, thus preventing further movement of the pigment particles and, consequently, loss of information after the magnetic orientation step. Preferably, step d), which cures the coating layer (x10) and one or more indicia (x30) at least partially in the curing apparatus (x50) described herein, either partially simultaneously with or subsequent to step c), is carried out by irradiation with UV-visible light (i.e., UV-Vis light radiation curing) or an E-beam (i.e., e-beam radiation curing), more preferably by irradiation with UV-Vis light. According to a preferred embodiment, the radiation-curable coating composition comprising non-spherical, preferably platelet-shaped magnetic or magnetizable pigment particles described herein is a UV-Vis curable coating composition.

[0083]

[0082] Preferably, the UV-Vis curable coating composition comprising non-spherical, preferably platelet-shaped magnetic or magnetizable pigment particles described herein is a radical curable composition; a cationic curable composition; or a radical cation (referred to as a hybrid in the art) curable composition. In other words, the UV-Vis curable coating composition preferably comprises monomers and / or oligomers selected from radical curable compounds, cationic curable compounds, and mixtures of radical and cationic curable compounds.

[0084]

[0083] The cation-curable composition contains one or more cationic compounds that are cured by a cationic mechanism typically involving activation by radiation of one or more photoinitiators that release cationic species, such as an acid, to react and / or crosslink monomers and / or oligomers, thereby curing the coating composition. Preferably, the one or more cation-curable compounds are selected from the group consisting of cyclic ethers such as vinyl ethers, propenyl ethers, epoxides, oxetanes, and tetrahydrofuran, lactones, cyclic thioethers, vinyl thioethers, propenyl thioethers, hydroxyl group-containing compounds, and mixtures thereof, preferably cyclic ethers such as vinyl ethers, propenyl ethers, epoxides, oxetanes, and tetrahydrofuran, lactones, and mixtures thereof.

[0085]

[0084] The radical-curable composition is cured by a free-radical mechanism typically involving activation by radiation of one or more photoinitiators, thereby generating radicals that initiate polymerization to cure the coating composition. Preferably, the radical-curable compound is preferably selected from (meth)acrylates selected from epoxy (meth)acrylates, (meth)acrylated oils, polyester and polyether (meth)acrylates, aliphatic or aromatic urethane (meth)acrylates, silicone (meth)acrylates, acrylic (meth)acrylates, and mixtures thereof. The term "(meth)acrylate" refers to acrylate and the corresponding methacrylate.

[0086]

[0085] The hybrid-curable composition contains one or more cationic compounds and one or more radical compounds that are cured by both mechanisms described herein.

[0087]

[0086] Depending on the compound used to prepare a UV-Vis curable coating composition containing non-spherical, preferably small plate-shaped magnetic or magnetizable pigment particles described herein, different photoinitiators may be used. Suitable examples of free radical photoinitiators are known to those skilled in the art and include, but are not limited to, acetophenone, benzophenone, benzyldimethylketal, α-amino ketone, α-hydroxy ketone, phosphine oxide, phosphine oxide derivatives, and mixtures of two or more thereof. Suitable examples of cationic photoinitiators are known to those skilled in the art and include, but are not limited to, onium salts such as organic iodonium salts (e.g., diaryliodonium salts), oxonium (e.g., triaryloxonium salts), and sulfonium salts (e.g., triarylsulfonium salts), and mixtures of two or more thereof. Other examples of useful photoinitiators can be found in standard textbooks. To achieve efficient curing, it may also be advantageous to include a photosensitizer in combination with one or more photoinitiators. Representative examples of suitable photosensitizers include, but are not limited to, isopropyl-thioxanthone (ITX), 1-chloro-2-propoxy-thioxanthone (CPTX), 2-chloro-thioxanthone (CTX), and 3,4-diethyl-thioxanthone (DETX), polymer derivatives (e.g., multifunctional thioxanthone compounds such as Omnipol TX, GENOPOL * TX-2, SpeedCure7010, etc.), and mixtures of two or more thereof. The one or more photoinitiators contained in the UV-Vis curable coating composition are preferably present in a total amount of about 0.1 wt% to about 20 wt%, more preferably 1 wt% to about 15 wt%, and the weight percent is based on the total weight of the UV-Vis curable coating composition.

[0088] [

[0087] ]The radiation-curable coating composition containing non-spherical, preferably small plate-shaped magnetic or magnetizable pigment particles described herein may further contain one or more coloring components selected from the group consisting of organic pigment particles, inorganic pigment fine particles, and organic dyes, and / or one or more additives. Examples of the latter include, but are not limited to, compounds and materials used to adjust physical, rheological, and chemical parameters of the coating composition such as viscosity (e.g., solvents, thickeners, and surfactants), consistency (e.g., anti-settling agents, fillers, and plasticizers), foamability (e.g., anti-foaming agents), lubricity (waxes, oils), UV stability (light stabilizers), adhesiveness, antistatic properties, storage stability (polymerization inhibitors), etc. The additives described herein may be present in the coating composition in known amounts and forms in the art, including so-called nanomaterials in which at least one of the dimensions of the additive is in the range of 1 to 1000 nm.

[0089] [

[0088] ]The radiation-curable coating composition containing non-spherical, preferably small plate-shaped magnetic or magnetizable pigment particles described herein may further contain one or more labeling substances or identifying additives selected from the group consisting of magnetic materials (different from the magnetic or magnetizable pigment particles described herein), luminescent materials, electroluminescent materials, up-converting materials, electrically conductive materials, and infrared absorbing materials, and / or one or more machine-readable materials. The term "machine-readable material" as used herein refers to a material that can be detected by a device or machine and exhibits at least one unique property that can be included in the coating to provide a method for authenticating the coating or an article containing the coating by using a specific device for its detection and / or authentication.

[0090]

[0089] The radiation-curable coating composition described herein, when present in the presence of the binder material described herein, disperses or mixes the magnetic or magnetizable pigment particles and one or more additives described herein (in particular, a UV-Vis curable coating composition preferably contains monomers and / or oligomers selected from radical curable compounds, cationic curable compounds, and mixtures of radical and cationic curable compounds), and may be prepared by forming a liquid composition. When present, one or more photoinitiators may be added to the composition during the dispersion or mixing step of all other components, or may be added at a later stage, i.e., after the formation of the liquid coating composition.

[0091]

[0090] The method described herein further includes step c) of applying the top coating composition described herein onto the coating layer (x10) described herein after step b) described herein. The top coating composition described herein is applied in the form of one or more indicia (x30) described herein, partially overlapping the coating layer (x10) described herein (i.e., overlapping in at least one area), the radiation-curable coating composition of the coating layer (x10) is in a wet and unpolymerized state, and the magnetic or magnetizable pigment particles are freely movable and rotatable.

[0092]

[0091] Preferably, the time between step b) described herein and step c) described herein is less than about 60 seconds, more preferably less than 5 seconds, and even more preferably less than about 2 seconds. In other words, the step of applying the top coating composition in the form of one or more indicia (x30) onto the coating layer (x10) is performed after step b), and the substrate (x20) supporting the coating layer (x10) is removed from the magnetic field of the magnetic field generating device.

[0093]

[0092] As used herein, the term "mark" means continuous and discontinuous layers consisting of the identification of markings or signs or patterns. Preferably, one or more marks (x30) described herein are selected from the group consisting of codes, symbols, alphanumeric symbols, motifs, geometric patterns (e.g., circles, triangles, and regular or irregular polygons), letters, words, numbers, logos, figures, portraits, and combinations thereof. Examples of codes include coded marks such as coded alphanumeric data, one-dimensional barcodes, two-dimensional barcodes, QR codes (registered trademark), data matrices, and IR-readable codes. One or more marks (x30) described herein may be solid marks and / or raster marks.

[0094]

[0093] The topcoating composition described herein is applied in the form of one or more marks (x30) described herein by an application process, preferably a non-contact fluid microdispensing process, which is preferably selected from the group consisting of spray coating, aerosol inkjet printing, electrohydrodynamic printing, and inkjet printing, more preferably an inkjet printing process, and the inkjet printing process is a variable information printing method that enables the creation of one or more marks (x30) on or within the optical effect layer (OEL) described herein. The application process is selected as a function of the design and resolution of the one or more marks to be created.

[0095]

[0094] Inkjet printing can be advantageously used to create an optical effect layer (OEL) that exhibits one or more marks described herein, including variable halftones. Inkjet halftone printing is a reproduction technique that simulates continuous-tone images containing an infinite number of colors or greys by the application of variable inkjet deposition amounts or basis weights.

[0096]

[0095] Spray coating is a technique in which a composition is pushed through a nozzle to form fine aerosols. Carrier gas and electrostatic charging may be relevant to function to direct the aerosol towards the surface to be printed. Spray printing enables printing spots and lines. Compositions suitable for spray printing typically have a viscosity of about 10 mPa·s to about 1 Pa·s (25 °C (1000 s -1 )). The resolution of spray coating printing is in the millimeter range. Spray printing is described, for example, in F.C. Krebs, Solar Energy Materials & Solar Cells (2009), 93, page 407.

[0097]

[0096] Aerosol inkjet printing (AJP) is a new non-contact direct writing approach aimed at providing fine features on a wide range of substrates. AJP accommodates a wide range of materials and free-form deposition and enables high resolution (about 10 micrometers) along with a relatively large stand-off distance (e.g., 1 - 5 mm) in addition to orientation independence. The technique involves aerosol generation using ultrasonic or pneumatic atomizers and typically generates aerosols from a composition having a viscosity of about 1 mPa·s to about 1 Pa·s (25 °C (1000 s -1 )). Aerosol jet printing is described, for example, in N.J. Wilkinson et al., The International Journal of Advanced Manufacturing Technology (2019) 105:4599 - 4619.

[0098]

[0097] Electrohydrodynamic inkjet printing is a high-resolution inkjet printing technology. Electrohydrodynamic inkjet printing technology uses an externally applied electric field to manipulate droplet size, ejection frequency, and placement on a substrate to obtain higher resolution than conventional inkjet printing while maintaining a high production speed. The resolution of electrohydrodynamic inkjet printing is approximately two orders of magnitude higher than that of conventional inkjet printing technology, and thus, it can be used for the orientation of nanoscale patterns and microscale patterns. Electrohydrodynamic inkjet printing may be used in both DOD or continuous mode. The composition for electrohydrodynamic inkjet printing typically has a viscosity of about 1 mPa·s to about 1 Pa·s (25 °C (1000 s -1 ). Electrohydrodynamic inkjet printing technology is described, for example, in P.V. Raje and N.C. Murmu, International Journal of Emerging Technology and Advanced Engineering, (2014), 4(5), pages 174 - 183.

[0099]

[0098] Slot die coating is a one-dimensional coating technology. Slot die coating enables the coating of stripes of materials that are well-suited for creating multilayer coatings in which stripes of different materials are layered on top of each other. Pattern alignment is achieved by moving the coating head along a direction perpendicular to the direction of web movement. The slot die coating head includes a mask that defines the slots of the coating head through which the slot die coating ink is dispensed. An example of a slot die coating head is described in F.C. Krebs, Solar Energy Materials & Solar Cells (2009), 93, pages 405 - 406. Compositions suitable for slot die coating typically have a viscosity of about 1 mPa·s to about 20 mPa·s (25 °C (1000 s -1 ).

[0100]

[0099] According to one embodiment, the top coating composition described herein is printed in the form of one or more indicia (x30) described herein by an inkjet printing process, preferably a continuous inkjet (CIJ) printing process, or a drop-on-demand (DOD) inkjet printing process, more preferably a drop-on-demand (DOD) inkjet printing process. Drop-on-demand (DOD) printing is a non-contact printing process where the droplets are generally created by an ejection mechanism rather than by destabilizing a jet if printing is required. Depending on the mechanism used in the print head to create the droplets, DOD printing is divided into piezoelectric impulse, thermal jet, valve jet (viscosity of about 1 mPa·s to about 1 Pa·s (25 °C (1000 s -1 ), and electrostatic processes.

[0101]

[0100] According to one embodiment, the top coating composition described herein includes one or more monomers and / or oligomers selected from radical curable compounds, cationic curable compounds, and mixtures of radical and cationic curable compounds, such as those described herein for the radiation curable coating composition containing magnetic or magnetizable pigment particles. For embodiments where the radiation curable coating composition containing magnetic or magnetizable pigment particles is a cationic curable composition, the top coating composition preferably includes one or more monomers and / or oligomers selected from cationic curable compounds, such as those described herein for the radiation curable coating composition. For embodiments where the radiation curable coating composition containing magnetic or magnetizable pigment particles is a radical curable composition, the top coating composition preferably includes one or more monomers and / or oligomers selected from radical curable compounds, such as those described herein for the radiation curable coating composition. For embodiments where the radiation curable coating composition containing magnetic or magnetizable pigment particles is a hybrid curable composition, the top coating composition preferably includes one or more monomers and / or oligomers selected from cationic curable compounds, such as those described herein for the radiation curable coating composition, and / or one or more monomers and / or oligomers selected from radical curable compounds. For embodiments where the top coating composition includes one or more monomers and / or oligomers selected from radical curable compounds, cationic curable compounds, and mixtures of radical and cationic curable compounds, such as those described herein for the radiation curable coating composition, and the top coating composition is applied by an inkjet printing process, the top coating composition may further include conventional additives and components such as wetting agents, defoaming agents, surfactants, (co)solvents, and mixtures thereof used, for example, in the field of radiation curable inkjet.

[0102] According to another embodiment, the top coating composition described herein includes one or more solvents. For embodiments in which the top coating composition described herein includes one or more solvents, an additional step of applying heat may be performed.

[0103] The top coating composition described herein may further include one or more labeling substances or identification additives and / or one or more machine-readable materials, such as those described for the coating layer (x10) including non-spherical magnetic or magnetizable pigment particles described herein, provided that the size of the substances, identification additives, and materials is suitable for the application process described herein. As described herein, the top coating composition described herein does not include magnetic or magnetizable pigment particles.

[0104] The method described herein further includes step d) of curing the coating layer (x10) and one or more indicia (x30) at least partially in a curing device (x50) described herein, either partially simultaneously with or after step c). By "partially simultaneously," it is meant that both steps are performed partially simultaneously, i.e., the times at which each step is performed overlap partially. In the context described herein, if curing is performed partially simultaneously with the application step c), it will be understood that the curing becomes effective after the formation of one or more indicia, prior to complete or partial curing.

[0105] Step c) of applying the top coating composition on the coating layer (x10) described herein and step d) of curing the coating layer (x10) and one or more indicia (x30) at least partially in the curing apparatus (x50) described herein are such that there is no intermediate step between them. For embodiments of the method described herein (see, e.g., FIGS. 2A, 2B, 2C, and 2E-1 to 2E-3), the time between said step c) and step d) is preferably about 0 to 5 minutes, more preferably about 0 to 1 minute, still more preferably about 0 to 10 seconds, and even more preferably about 0 to 5 seconds.

[0106]

[0105] At least a partial curing step as described herein is at least a partial curing step of radiation, with UV-Vis light radiation curing being more preferred, since these techniques advantageously result in a very fast curing process and thus significantly reduce the preparation time of any article containing the OEL described herein. Further, radiation curing has the advantage of causing an almost instantaneous increase in the viscosity of the coating composition. Radiation curing by photopolymerization is particularly preferred under the influence of chemiluminescence having wavelength components in the UV or blue part of the electromagnetic spectrum (typically, 200 nm to 650 nm, more preferably 200 nm to 420 nm). A device for UV-visible curing may include, as a chemical radiation source, a high-performance light-emitting diode (LED) lamp, or an arc discharge lamp such as a medium-pressure mercury arc (MPMA) or a metal vapor arc lamp. Step d) of at least partially curing the coating layer (x10) and one or more indicia (x30) is carried out in the curing apparatus (x50) described. Suitable curing units include devices for UV-visible curing that include, as a chemical radiation source, a high-performance light-emitting diode (LED) lamp, or an arc discharge lamp such as a medium-pressure mercury arc (MPMA) or a metal vapor arc lamp.

[0107]

[0106] Some embodiments for step b) and y) of exposing the coating layer (x10) to the magnetic field of the magnetic field generating apparatus described herein are shown in FIGS. 2A-E.

[0108] According to one embodiment shown in FIG. 2A, the method described herein is Step b) of exposing the coating layer (x10) to the magnetic field of a magnetic field generating device (B1) to orient at least a portion of the magnetic or magnetizable pigment particles in a uniaxial direction; Step c), which is a step of applying a top coating composition onto the coating layer (x10) after step b), wherein the top coating composition is applied in the form of one or more markings (x30) described herein; and Including step d) of curing the coating layer (x10) and one or more markings (x30) at least partially with a curing device (x50) described herein, either partially simultaneously with step c) or thereafter.

[0109] According to one embodiment shown in FIG. 2B, the method described herein is Exposing the coating layer (x10) to the magnetic field of a magnetic field generating device (B1) to orient at least a portion of the magnetic or magnetizable pigment particles in a biaxial direction, wherein the magnetic or magnetizable pigment particles are platelet-shaped magnetic or magnetizable pigment particles having an X-axis and a Y-axis defining a major plane of extension of the particles, and preferably, the step is performed to orient at least a portion of the platelet-shaped magnetic or magnetizable pigment particles in a biaxial direction such that both the X-axis and the Y-axis are substantially parallel to the substrate surface; step b); Step c), which is a step of applying a top coating composition onto the coating layer (x10) after step b), wherein the top coating composition is applied in the form of one or more markings (x30) described herein; and Including step d) of curing the coating layer (x10) and one or more markings (x30) at least partially with a curing device (x50) described herein, either partially simultaneously with step c) or thereafter.

[0110] According to one embodiment, the method described herein is Step b) described in this specification, which consists of two steps. The first step b1) consists of exposing the coating layer (x10) to the magnetic field of a magnetic field generating device (B1) in order to orient at least a part of the magnetic or magnetizable pigment particles in a biaxial direction. The magnetic or magnetizable pigment particles are platelet-shaped magnetic or magnetizable pigment particles having an X-axis and a Y-axis that define the main extended surfaces of the particles. A further step b2) consists of exposing the coating layer (x10) to the magnetic field of a second magnetic field generating device (B2) in order to reorient at least a part of the platelet-shaped magnetic or magnetizable particles in a uniaxial direction. The step b2) is carried out partially simultaneously with, simultaneously with, or after step b1) (see Figure 2C where step b2) is carried out on step b1)); Step c), which is a step of applying a top coating composition onto the coating layer (x10) after step b), and the top coating composition is applied in the form of one or more markings (x30) described in this specification; and Step d), which includes curing the coating layer (x10) and one or more markings (x30) at least partially in a curing device (x50) described in this specification, is carried out partially simultaneously with or after step c).

[0111]

[0110] According to another embodiment shown in Figure 2D-1, the method described in this specification is Step b) of exposing the coating layer (x10) to the magnetic field of a magnetic field generating device (B1) in order to orient at least a part of the magnetic or magnetizable pigment particles in a uniaxial direction; Step c), which is a step of applying a top coating composition onto the coating layer (x10) after step b), and the top coating composition is applied in the form of one or more markings (x30) described in this specification; Simultaneously at least in part with or after step c), one or more first areas of the coating layer (x10) are selectively at least partially cured so that one or more second areas of the coating layer (x10) remain unexposed to irradiation, fixing at least some of the magnetic or magnetizable particles in their adopted positions and orientations, and the step of selectively at least partially curing is step x) performed by a selective curing device (x60) described herein; After step x), step y) of exposing the coating layer (x10) to the magnetic field of a second magnetic field generating device (B2) to orient at least some of the magnetic or magnetizable pigment particles of one or more second areas of the coating layer (x10) in a uniaxial direction; and Including step d) of at least partially curing the coating layer (x10) and one or more indicia (x30) in a curing device (x50) described herein, at least in part simultaneously with or after step y), Said step y) is performed at least in part simultaneously with or before step d).

[0112] According to another embodiment shown in FIG. 2D-2, the method described herein is Step b) of exposing the coating layer (x10) to the magnetic field of a magnetic field generating device (B1) performed to orient at least some of the magnetic or magnetizable pigment particles in a biaxial direction; After step b), step c) which is the step of applying a top coating composition onto the coating layer (x10), said top coating composition being applied in the form of one or more indicia (x30) described herein; Step c) is carried out, at least in part, simultaneously with, or subsequent to, the selective at least partial hardening of one or more first areas of the coating layer (x10) such that one or more second areas of the coating layer (x10) are not exposed to the irradiation, thereby fixing at least a portion of the magnetic or magnetizable particles in their adopted positions and orientations. The step of selectively at least partially hardening is step x) carried out by a selective hardening device (x60) as described herein; After step x), step y) of exposing the coating layer (x10) to the magnetic field of a second magnetic field generating device (B2) to orient at least a portion of the magnetic or magnetizable pigment particles of one or more second areas of the coating layer (x10) in a uniaxial direction; and Step d) of at least partially hardening the coating layer (x10) and one or more indicia (x30) in a hardening device (x50) as described herein, at least in part, simultaneously with, or subsequent to, step y).

[0113]

[0112] According to another embodiment, the method described herein is Step b1) consisting of two steps described herein. The first step b1) consists of exposing the coating layer (x10) to the magnetic field of a magnetic field generating device (B1) to orient at least a portion of the magnetic or magnetizable pigment particles in a biaxial direction. A further step b2) consists of exposing the coating layer (x10) to the magnetic field of a second magnetic field generating device (B2) to reorient at least a portion of the magnetic or magnetizable particles in the form of platelets in a uniaxial direction. The further step b2) is carried out at least in part, simultaneously with, simultaneously with, or subsequent to step b1) (see Figure 2D-3 where step b2) is carried out after step b1)); Step c), which is the step of applying a top coating composition onto the coating layer (x10), wherein the top coating composition is applied in the form of one or more indicia (x30) as described herein; Simultaneously, at least in part, with or after step c), one or more first areas of the coating layer (x10) are selectively at least partially cured so that one or more second areas of the coating layer (x10) remain unexposed to irradiation, fixing at least a portion of the magnetic or magnetizable particles in their employed positions and orientations, the step of selectively at least partially curing being step x) carried out by a selective curing device (x60) as described herein; After step x), step y) of exposing the coating layer (x10) to the magnetic field of a third magnetic field generating device (B3) to reorient at least a portion of the magnetic or magnetizable pigment particles of one or more second areas of the coating layer (x10) in a uniaxial direction; and Including step d) of at least partially curing the coating layer (x10) and one or more indicia (x30) with a curing device (x50) as described herein, simultaneously, at least in part, with or after step y).

[0114] According to another embodiment shown in FIG. 2E-1, the method as described herein is Step b) of exposing the coating layer (x10) to the magnetic field of a magnetic field generating device (B1) carried out to orient at least a portion of the magnetic or magnetizable pigment particles in a uniaxial direction; Simultaneously, at least in part, with or after step b), one or more first areas of the coating layer (x10) are selectively at least partially cured so that one or more second areas of the coating layer (x10) remain unexposed to irradiation, fixing at least a portion of the magnetic or magnetizable particles in their employed positions and orientations, the step of selectively at least partially curing being step x) carried out by a selective curing device (x60) as described herein; After step x), step y) of exposing the coating layer (x10) to the magnetic field of a second magnetic field generating device (B2) to reorient at least a portion of the magnetic or magnetizable pigment particles of one or more second areas of the coating layer (x10) in a uniaxial direction; Step y), which is a step of applying a top coating composition onto the coating layer (x10), wherein the top coating composition is applied in the form of one or more marks (x30) described herein; and Step d), which includes curing the coating layer (x10) and one or more marks (x30) at least partially with a curing device (x50) described herein, either partially simultaneously with or after step c).

[0115] According to another embodiment shown in FIG. 2E-2, the method described herein Step b), which exposes the coating layer (x10) to the magnetic field of a magnetic field generating device (B1) to orient at least a portion of the magnetic or magnetizable pigment particles in a biaxial direction; Step x), which selectively cures at least partially one or more first areas of the coating layer (x10) such that one or more second areas of the coating layer (x10) remain unexposed to irradiation, thereby fixing at least a portion of the magnetic or magnetizable particles in their adopted positions and orientations, and the step of selectively curing at least partially is performed by a selective curing device (x60) described herein; Step y), which exposes the coating layer (x10) to the magnetic field of a second magnetic field generating device (B2) to orient at least a portion of the magnetic or magnetizable pigment particles in a uniaxial direction in one or more second areas of the coating layer (x10) after step x); Step c), which is a step of applying a top coating composition onto the coating layer (x10) after step y), wherein the top coating composition is applied in the form of one or more marks (x30) described herein; and Step d), which includes curing the coating layer (x10) and one or more marks (x30) at least partially with a curing device (x50) described herein, either partially simultaneously with or after step c).

[0116] According to another embodiment, the method described herein is step b) consisting of two steps described herein, wherein the first step b1) consists of exposing the coating layer (x10) to the magnetic field of a magnetic field generating device (B1) in order to orient at least some of the magnetic or magnetizable pigment particles in a biaxial direction, and a further step b2) consists of exposing the coating layer (x10) to the magnetic field of a second magnetic field generating device (B2) in order to orient at least some of the platelet-shaped magnetic or magnetizable particles in a uniaxial direction, said further step b2) being carried out partially simultaneously with, simultaneously with, or subsequent to step b1) (see Figure 2E-3 where step b2) is carried out after step b1)); After step b), or partially simultaneously therewith, at least partially curing one or more first areas of the coating layer (x10) of the radiation-curable coating composition of step b) in order to fix at least some of the magnetic or magnetizable particles in their adopted positions and orientations such that one or more second areas of the coating layer (x10) remain unexposed to irradiation, said at least partially curing step being step x) carried out by a selective curing device (x60) described herein; After step x), step y) of exposing the coating layer (x10) to the magnetic field of a third magnetic field generating device (B3) in order to orient at least some of the magnetic or magnetizable pigment particles of one or more second areas of the coating layer (x10) in a uniaxial direction; After step y), step c) of applying a top coating composition onto the coating layer (x10), said top coating composition being applied in the form of one or more markings (x30) described herein; and Including step d) of at least partially curing the coating layer (x10) and one or more markings (x30) in a curing device (x50) described herein, partially simultaneously with or subsequent to step c).

[0117] For embodiments described herein including step x) of selectively at least partially curing one or more first areas of a coating layer (x10) of the radiation curable coating composition of step b) or step c) such that one or more second areas of the coating layer (x10) are left unexposed to the irradiation described herein, a selective curing apparatus (x60) is used to fix at least a portion of the magnetic or magnetizable particles in their employed positions and orientations. The selective curing enables the creation of an optical effect layer (OEL) exhibiting motifs consisting of different areas, said different areas having different magnetic orientation patterns. The selective curing apparatus (x60) may comprise a curing apparatus (x50) described herein and one or more fixed or removable photomasks including one or more spaces corresponding to patterns formed as part of the coating layer. Alternatively, the selective curing apparatus (x60) may be addressable, such as a scanning laser beam disclosed in European Patent Application Publication No. 2468423, an array of light emitting diodes (LEDs) disclosed in International Publication No. 2017 / 021504, or a chemically addressable LED light source (x41) including an array of individually addressable actinic emitters disclosed in International Application PCT / EP2019 / 087072 of a co-pending patent application.

[0118]

[0117] The present invention provides a method as described herein for producing a substrate (x20) comprising an optical effect layer (OEL) exhibiting one or more indicia (x30) on a substrate (x20) as described herein and a resulting substrate (x20) comprising one or more optical effect layers (OEL). The substrate (x20) as described herein is preferably selected from the group consisting of paper or other fibrous materials (including woven and non-woven fibrous materials) such as cellulose, paper-containing materials, glass, metal, ceramic, plastic and polymer, metallized plastic or polymer, composite materials, and mixtures or combinations of two or more thereof. Typical papers, paper-like or other fibrous materials consist of various fibers including, but not limited to, abaca, cotton, linen, wood pulp, and mixtures thereof. As is well known to those skilled in the art, cotton and cotton / linen mixtures are preferred for banknotes, while wood pulp is commonly used in non-banknote security documents. According to other embodiments, the substrate (x20) as described herein is based on plastic and polymer, metallized plastic or polymer, composite materials, and mixtures or combinations of two or more thereof. Suitable examples of plastics and polymers include polyolefins such as polyethylene (PE) and polypropylene (PP) including biaxially oriented polypropylene (BOPP), polyamides, polyesters such as poly(ethylene terephthalate) (PET), poly(1,4-butylene terephthalate) (PBT), poly(ethylene 2,6-naphthalate) (PEN), and polyvinyl chloride (PVC). Spunbond olefin fibers such as those sold under the trademark Tyvek® may also be used as the substrate. Representative examples of metallized plastics or polymers include the above-mentioned plastic or polymeric materials with metal disposed continuously or discontinuously on the surface. Representative examples of metals include, but are not limited to, aluminum (Al), chromium (Cr), copper (Cu), gold (Au), silver (Ag), their alloys, and combinations of two or more of the aforementioned metals. The metallization of the plastic or polymeric material may be carried out by an electroplating process, a high-vacuum coating process, or a sputtering process.Representative examples of composite materials include, but are not limited to, multi-layer structures or laminates of paper and at least one plastic or polymeric material such as those described above, and plastics and / or polymer fibers incorporated into paper-like or fibrous materials such as those described above. Of course, the substrate can further include additives known to those skilled in the art, such as fillers, adhesives, bleaching agents, processing aids, reinforcing agents, or wet strength enhancers. When an OEL indicating one or more marks (x30) produced by the present invention is used for decorative or cosmetic purposes, for example, including nail lacquer, the OEL may be produced on other types of substrates including animal or human nails, artificial nails, or other parts.

[0119]

[0118] Also described herein is a method for manufacturing a security document, or a decorative element or ornament, the method comprising: a) providing a security document, or a decorative element or ornament; b) providing one or more optical effect layers described herein, such as those obtained by the methods described herein, to be included in the security document, or the decorative element or ornament.

[0120]

[0119] If the OEL produced by the present invention is on a security document or article, for the purpose of further improving the security level and resistance to forgery and illegal replication of the security document or article, the substrate may include printing, coating, or laser marking or laser perforation marks, watermarks, anti-forgery threads, fibers, blanks, luminescent compounds, windows, foils, decals, and combinations of two or more thereof. For the same purpose of further improving the security level and resistance to forgery and illegal replication of security documents and articles, the substrate may include one or more labeling substances or identification additives and / or machine-readable substances (e.g., luminescent substances, UV / visible / IR absorbing substances, magnetic substances, and combinations thereof).

[0121]

[0120] Optionally, the primer layer may be applied to the substrate before step a). This can enhance the quality of the OEL described herein or promote adhesion. Examples of such primer layers can be found in WO 2010 / 058026.

[0122]

[0121] For the purpose of improving the durability or chemical resistance to dirt and cleanliness, and thus the cycle life of security documents, articles, or decorative elements or ornaments containing the OEL obtained by the method described herein, or for the purpose of changing their aesthetic appearance (e.g., optical gloss), one or more protective layers may be applied over the OEL. When present, one or more protective layers typically consist of a protective varnish. The protective varnish may be a radiation-curable composition, a heat-drying composition, or any combination thereof. Preferably, one or more protective layers are radiation-curable compositions, more preferably UV-Vis curable compositions. The protective layer is typically applied after the formation of the OEL.

[0123]

[0122] The present invention further provides an optical effect layer (OEL) showing one or more marks (x30) described herein and produced by the method described herein. The shape of the optical effect layer (OEL) described herein may be continuous or discontinuous. According to one embodiment, the shape of the coating layer (x10) represents one or more marks, dots, and / or lines, and the marks may have the same shape as one or more marks (x30) consisting of the top coating composition described herein, or may have different shapes.

[0124]

[0123] The OEL indicating one or more indicia (x30) described in this specification may be provided directly on the substrate on which it remains permanently (such as for banknote applications). Alternatively, the optical effect layer may also be provided on a temporary substrate for manufacturing purposes on which the OEL is subsequently removed. This can, in particular, facilitate the production of the optical effect layer (OEL), for example, while the binder material is still in its fluid state. Subsequently, after curing the coating composition for the production of the OEL, the temporary substrate may be removed from the OEL.

[0125]

[0124] Alternatively, in other embodiments, the adhesive layer may be present on one or more indicia (x30) shown, or on the substrate side containing the OEL, and the adhesive layer may be on the substrate opposite to the side on which the OEL is provided, or on the same side as the OEL, and on the OEL. Thus, the adhesive layer may be applied to the OEL or the substrate, and the adhesive layer may be applied after the curing step is completed. Such articles may be attached to various types of documents or other articles or commodities without machinery and printing and other processes with fairly high effects. Alternatively, the substrate described in this specification containing the OEL described in this specification may be in the form of a transfer foil, which can be applied to a document or article in an individual transfer step. For this purpose, the substrate is provided with a release coating on which the OEL is provided as described in this specification. One or more adhesive layers may be applied to the optical effect layer provided in this way.

[0126]

[0125] Also described in this specification are substrates containing more than one, i.e., two, three, four, etc., optical effect layers (OELs) obtained by the method described in this specification.

[0127]

[0126] Also described in this specification are articles, documents, in particular security documents, decorative elements, and ornaments containing an optical effect layer (OEL) produced by the present invention. Articles, in particular security documents, decorative elements, or ornaments may contain more than one (for example, two, three, etc.) OELs produced by the present invention.

[0128] As described above, the OEL produced according to the present invention may be used for decorative purposes and to protect and authenticate security documents.

[0129]

[0128] Representative examples of decorative elements or objects include, but are not limited to, luxury goods, cosmetic packaging, automotive parts, electronic / electrical appliances, furniture, and nail items.

[0130]

[0129] Examples of security documents include, but are not limited to, value documents and value goods. Representative examples of value documents include, but are not limited to, banknotes, certificates, tickets, invoices, certificates, revenue stamps, and tax labels, agreements, etc., passports, identity documents, visas, driver's licenses, bank cards, credit cards, transaction cards, access documents or cards, admission tickets, public transportation tickets, academic graduation certificates or rights, etc., preferably identity documents such as banknotes, identity documents, entitlement documents, driver's licenses, and credit cards. The term "value goods" particularly refers to packaging materials for articles that are protected from forgery and / or illegal replication in order to guarantee the contents of the package, such as cosmetics, dietary supplements, pharmaceuticals, alcohol, tobacco items, beverages or food, electrical / electronic items, textiles or jewels, i.e., for example, for genuine pharmaceutical products. Examples of these packaging materials include, but are not limited to, labels such as authentication brand labels, tamp-proof labels, and seals. It is pointed out that the disclosed substrates, value documents, and value goods are given solely for purposes of illustration without limiting the scope of the present invention.

[0131]

[0130] Alternatively, the optical effect layer (OEL) described herein may be provided on an auxiliary substrate such as, for example, a security thread, security stripe, foil, decal, window, or label, and thus may be transferred to a security document in a separate step.

[0132]

[0131] Those skilled in the art can anticipate some changes from the above specific embodiments without departing from the spirit of the present invention. Such changes are encompassed by the present invention.

[0133]

[0132] Furthermore, all documents referred to throughout the specification are hereby incorporated by reference in their entirety as if fully set forth herein.

[0134] Examples

[0133] The present invention will now be described in more detail with reference to the following non-limiting examples. The following examples describe in more detail the preparation of an optical effect layer (OEL) showing one or more indicia. Four series of combinations of UV-Vis curable screen printing compositions and top coating inkjet printing compositions are prepared and described in Tables 1-3. Table 1A: Combinations (E1, E3-E6, and C1-C5) of radical UV-Vis curable screen printing compositions and top coating inkjet printing compositions containing platelet-shaped magnetic or magnetizable pigment particles. Table 1B: Combination (E2) of radical UV-Vis curable screen printing compositions and top coating inkjet printing compositions containing platelet-shaped magnetic or magnetizable pigment particles. Table 1C: Combination (C11) of radical UV-Vis curable screen printing compositions and top coating inkjet printing compositions containing platelet-shaped magnetic or magnetizable pigment particles. Table 2: Combinations (E7-E11, E17, E19-E21, and C6-C10) of cationic UV-Vis curable screen printing compositions and top coating inkjet printing compositions containing platelet-shaped magnetic or magnetizable pigment particles. Table 3: Combinations (E12-E16 and E18) of hybrid UV-Vis curable screen printing compositions and top coating inkjet printing compositions containing platelet-shaped magnetic or magnetizable pigment particles.

[0135]

Table 1

[0136]

Table 2

[0137]

Table 3

[0138]

Table 4

[0139]

Table 5

[0140]

Table 6

[0141] Preparation of the Composition

[0134] The UV-Vis curable screen printing composition was independently prepared by mixing the components shown in Tables 1 to 3 at 2000 rpm for 10 minutes using a Dispermat CV-3.

[0142]

[0135] The top coating inkjet printing composition was independently prepared by mixing the components shown in Tables 2 to 3 at room temperature and 1000 rpm for 10 minutes using a Dispermat (LC220-12).

[0143]

[0136] The viscosity of the composition was independently measured at 25 °C using a Brookfield viscometer (model "DV-I Prime", spindle S27 at 100 rpm for the UV-Vis curable screen printing composition and spindle S00 at 50 rpm for the top coating inkjet printing composition), and is shown in Tables 1 to 4. Method for Preparing the Optical Effect Layer (OEL)

[0137] The optical effect layer (OEL) was prepared by the methods (E1 to E21) of the present invention and the comparative methods (C1 to C11). Tables 5A to C provide an overview of i) the combinations of the compositions used during the printing method, ii) diagrams schematically showing the methods themselves, iii) the substrates to which the UV-Vis curable screen printing composition was applied, and iv) the number of passes on the magnetic field generating device during magnetic biaxial orientation.

[0144]

Table 7

[0145]

Table 8

[0146]

Table 9

[0147] Substrates (x20) Nos. 1 to 3 were as follows: Substrate No. 1 was a polymer substrate (Guardian (trademark) of CCL Secure), substrate No. 2 was credit paper (Louisenthal BNP paper 100 g / m 2 ), and substrate No. 3 was credit paper (Louisenthal BNP paper 100 g / m 2 coated by hand screen printing using a T90 screen with the primer composition disclosed in Table 4 (primer thickness 20 μm) cured by UV irradiation (two lamps: an iron-doped mercury lamp of IST Metz 200 W / cm 2 + mercury lamp 200 W / cm 2 ) at 2 passes and 100 m / min.

[0148]

[0138] In Figure 2A (method according to the present invention), the method comprises the following steps: Screen printing a UV-Vis curable screen printing composition onto a substrate (220) to form a coating layer (210) Step a) (not shown), After step a), at least a part of the magnetic or magnetizable pigment particles is oriented in a uniaxial direction Step b) , After step b), an inkjet printing of a top coating inkjet printing composition is carried out to form the mark (230) Step c) , and After step c), the coating layer (210) and the mark (230) are cured in a curing device (250) to form an optical effect layer Step d) was included.

[0149]

[0139] For all examples (E6, E11, E16, and 21) produced by the method according to the present invention, it was about 1.2 seconds between step b) and step c). For the examples (E6, E11, E16, and 21) produced by the method according to the present invention, it was less than 10 seconds between step c) and step d).

[0150]

[0140] In FIG. 2B (method according to the present invention), the method comprises the following steps: A UV-Vis curable screen printing composition is screen printed on a substrate (220) to form a coating layer (210) Step a) (not shown), After step a), at least a part of the magnetic or magnetizable pigment particles is oriented in a biaxial direction Step b) , After step b), an inkjet printing of a top coating inkjet printing composition is carried out to form the mark (230) Step c) , and After step c), the coating layer (210) and the mark (230) are cured in a curing device (250) to form an optical effect layer Step d) was included.

[0151]

[0141] For all the examples (E1 - E4, E7 - E9, E12 - E14, E17 - 18, E19) produced by the method according to the invention, it was about 1.2 seconds between step b) and step c). It was 5 minutes between step c) and step d), for example, between E4, E9 and E14. In all other examples E1 - E3, E7 - 8, E12 - 13, E17 - 18, and E19, the period was less than 10 seconds.

[0152]

[0142] In Figure 2C (method according to the invention), the method comprises the following steps: Screen - printing a UV - Vis curable screen - printing composition onto a substrate (220) to form a coating layer (210) Step a) (not shown) After step a), step b) which consists of two steps. The first step b1) consists of orienting at least a part of the magnetic or magnetizable pigment particles in a biaxial direction, and the subsequent step b2) consists of re - orienting at least a part of the magnetic or magnetizable particles in a uniaxial direction. Step b) 、 After step b), ink - jet printing a top - coating ink - jet printing composition to form a mark (230) Step c) 、and After step c), curing the coating layer (210) and the mark (230) in a curing device (250) to form an optical effect layer Step d) was included.

[0153]

[0143] For all the examples (E5, E10, E15, and E20) produced by the method according to the invention, it was about 1.2 seconds between step b2) and step c). For examples E5, E10, E15, and E20 produced by the method according to the invention, it was about 1.2 seconds between step c) and step d).

[0154]

[0144] In Figure 4A (comparative method), the method comprises the following steps: To form the coating layer (410), a UV-Vis curable screen printing composition is screen printed onto the substrate (420). Step a) (not shown), After step a), to form the mark (430), a top coating inkjet printing composition is inkjet printed. Step c) and After step c), to form the optical effect layer, the coating layer (410) and the mark (430) are cured in a curing device (450). Step d) were included.

[0155]

[0145] For all examples (C1 and C6) produced by this comparative method, it was about 1.2 seconds between step c) and step d).

[0156]

[0146] In Figure 4B (comparative method), the method comprises the following steps: To form the coating layer (410), a UV-Vis curable screen printing composition is screen printed onto the substrate (420). Step a) (not shown), After step a), to form the mark (430), a top coating inkjet printing composition is inkjet printed. Step c) , After step c), at least a part of the magnetic or magnetizable pigment particles is oriented in the biaxial direction. Step b) and After step c), to form the optical effect layer, the coating layer (410) and the mark (430) are cured. Step d) were included.

[0157]

[0147] For all examples (C2 and C7) produced by this comparative method, it was about 10 seconds between step c) and step b), and 2.4 seconds between step b) and step d).

[0158]

[0148] In Figure 4C (comparative method), the method comprises the following steps: To form the coating layer (410), screen-print a UV-Vis bis-curable screen printing composition onto the substrate (420). Step a) (not shown), After step a), at least some of the magnetic or magnetizable pigment particles are oriented in a biaxial direction. Step b) / b1) , After step / b1), to form the mark (430), inkjet print a top coating inkjet printing composition. Step c) , After step c), at least some of the magnetic or magnetizable pigment particles are reoriented in a uniaxial direction. Step b2) , After step b2), to form the optical effect layer, cure the coating layer (410) and the mark (430) in a curing device (450). Step d) was included.

[0159]

[0149] For all examples (C3 and C8) produced by this comparative method, it was about 0.3 seconds between step b1) and step c), about 1.2 seconds between step c) and step b2), and about 3.2 seconds between step b2) and step d).

[0160]

[0150] In Figure 4D (comparative method), the method comprises the following steps: To form the coating layer (410), screen-print a UV-Vis curable screen printing composition onto the substrate (420). Step a) (not shown), After step a), at least some of the magnetic or magnetizable pigment particles are oriented in a biaxial direction. Step b1) , After step b) / b1), to form the mark (430), inkjet print a top coating inkjet printing composition. Step c) , After step c), at least some of the magnetic or magnetizable pigment particles are reoriented in a uniaxial direction. Step b2) , and Simultaneously, at least in part, with step b) / b2), the coating layer (410) and the indicia (430) are cured in a curing device (450) to form an optical effect layer. Step d) It included.

[0161]

[0151] For all examples (C4 and C9) produced by this comparison method, it was about 0.3 seconds between step b1) and step c), and about 1.2 seconds between step c) and b2).

[0162]

[0152] In FIG. 4E (comparison method), the method includes the following steps: To form a coating layer (410), a UV-Vis curable screen printing composition is screen printed onto a substrate (420). Step a) (not shown), After step a), at least a part of the magnetic or magnetizable pigment particles are oriented in a uniaxial direction. Step b) , Simultaneously, at least in part, with step b) (i.e., while the substrate (420) is maintained in the magnetic field (B1) of a magnetic field generating device), a top coating inkjet printing composition is inkjet printed to form indicia (430). Step c) , Simultaneously, at least in part, with step b) (i.e., while it maintains the substrate (420) in the magnetic field (B1) of a magnetic field generating device), but after step c), the coating layer (410) and the indicia (430) are cured in a curing device (450) to form an optical effect layer. Step d) It included.

[0163]

[0153] For all examples (C5 and C10) produced by this comparison method, it was about 2.2 seconds between step c) and step d).

[0164]

[0154] In FIG. 4F (comparison method), the method includes the following steps: To form a coating layer (410), a UV-Vis curable screen printing composition is screen printed onto a substrate (420). Step (not shown), After said step, at least a part of the magnetic or magnetizable pigment particles is oriented in a uniaxial direction Step b) , Curing the coating layer (410) with a curing device, partially simultaneously with step b) (i.e., while maintaining the substrate (420) in the magnetic field (B1) of the magnetic field generating device) Step d) , After said step d), inkjet printing a top coating inkjet printing composition to form the mark (430) Step c) , After said step c), curing the mark (430) with a curing device Step was included.

[0165]

[0155] For the example (C11) produced by this comparative method, it was about 5 seconds between the last two steps.

[0166] Screen printing of the UV-Vis curable screen printing composition

[0156] The UV-Vis curable screen printing compositions described in Tables 1 to 3 were independently applied by hand screen printing using a T90 screen on a substrate (x20) (70 mm × 70 mm) described in Table 5 to form a coating layer (x10) having the following dimensions: 25 mm × 25 mm and a thickness of about 20 μm.

[0167] Magnetic orientation of the UV-Vis curable screen printing composition

[0157] After the screen printing step described herein, the step of exposing the coating layer (x10) to the magnetic field of the magnetic field generating device described below was performed to orient at least a part of the magnetic or magnetizable pigment particles.

[0168] Magnetic field generating device for biaxial orientation (shown in FIG. 3)

[0158] The magnetic field generating device used to orient at least a part of the magnetic or magnetizable pigment particles in a biaxial direction is a) a first bar-shaped dipole magnet (371) and two second bar-shaped dipole magnets (372 a and 372 bA first set (S1) including ), a first bar-shaped dipole magnet (371), and a second bar-shaped dipole magnet (372 a and 372 b ), a second set (S2), and b) a third bar-shaped dipole magnet (373 a and 373 b ). A pair (P1) was included.

[0169]

[0159] For the first bar-shaped dipole magnet (371) of the first and second sets (S1, S2), with respect to the second bar-shaped dipole magnet (372 a and 372 b ) of the first and second sets (S1, S2), and for the third bar-shaped dipole magnet (373 a and 373 b ) of the pair (P1), the outermost surfaces were on the same plane.

[0170]

[0160] The third bar-shaped dipole magnet (373 a ) was aligned with the second bar-shaped dipole magnet (372 a ) of the first set (S1) and the second bar-shaped dipole magnet (372 a ) of the second set (S2) to form a line. The third bar-shaped dipole magnet (373 b ) was aligned with the second bar-shaped dipole magnet (372 b ) of the first set (S1) and the second bar-shaped dipole magnet (372 b ) of the second set (S2) to form a line.

[0171]

[0161] The first bar-shaped dipole magnets (371) of the first and second sets (S1, S2) had the following dimensions: a first thickness (L1) of 5 mm, a first length (L4) of 60 mm, and a first width (L5) of 40 mm. The second bar-shaped dipole magnets (372 a and 372 bEach of ) had the following dimensions: a second thickness (L2) of 10 mm, a second length (L6) of 40 mm, and a second width (L7) of 10 mm. Each of a pair of (P1) third bar-shaped dipole magnets (373a and 373b) had the following dimensions: a third thickness (L3) of 10 mm, a third length (L8) of 20 mm, and a third width (L9) of 10 mm.

[0172]

[0162] The first bar-shaped dipole magnet (371) of the first set (S1) and the second bar-shaped dipole magnet (372 a and 372 b ) of the first set (S1) were aligned to form a column, and the first bar-shaped dipole magnet (371) and the second bar-shaped dipole magnet (372 a and 372 b ) of the second set (S2) were aligned to form a column. For each set (S1, S2) and each column described herein, the first bar-shaped dipole magnet (371) and the two second bar-shaped dipole magnets (372 a and 372 b ) were separated by a second distance (d2) of 2 mm. For each line described herein, the third bar-shaped dipole magnets (373 a and 373 b ) and the two second bar-shaped dipole magnets (372 a ) were separated by a third distance (d3) of 2 mm.

[0173]

[0163] The first bar-shaped dipole magnets (371) of the first and second sets (S1, S2) had magnetic axes oriented substantially parallel to the substrate (320), and the first bar-shaped dipole magnet (371) of the first set (S1) had a magnetic direction opposite to the magnetic direction of the first bar-shaped dipole magnet (371) of the second set (S2), and were separated by a first distance (d1) of 24 mm corresponding to the sum of the third length (L8) and the two third distances (d3).

[0174]

[0164] The two second bar-shaped dipole magnets (372 a and 372 b) had a magnetic axis oriented substantially perpendicular to the first plane and substantially perpendicular to the substrate (320). The S pole of the second bar-shaped dipole magnet (372 a ) of the first set (S1) faced the first plane and the substrate (320), and the N pole of the second bar-shaped dipole magnet (372 b ) faced the substrate (320). The N pole of the first bar-shaped dipole magnet (371) of the first set (S1) faced the second bar-shaped dipole magnet (372 b ) of the first set (S1). The N pole of the second bar-shaped dipole magnet (372 a ) of the second set (S2) faced the first plane and the substrate (320), and the S pole of the second bar-shaped dipole magnet (372 b ) of the second set (S2) faced the substrate (320). The N pole of the first bar-shaped dipole magnet (371) of the second set (S2) faced the second bar-shaped dipole magnet (372 a ).

[0175]

[0165] The S pole of the third bar-shaped dipole magnet (373 a ) faced the second bar-shaped dipole magnet (372 a ) of the first set (S1). The second bar-shaped dipole magnet (372 a ) had an S pole facing the substrate (320). The N pole of the third bar-shaped dipole magnet (373 b ) faced the second bar-shaped dipole magnet (372 b ) of the first set (S1). The second bar-shaped dipole magnet (372 b ) had an N pole facing the substrate (320).

[0176]

[0166] The first bar-shaped dipole magnets (371) of the first and second sets (S1, S2), the second bar-shaped dipole magnets (373 a and 373 b ) of the first and second sets (S1, S2), and a pair (P1) of third bar-shaped dipole magnets (372 a and 372 b) is made of NdFeB N42 and is embedded in a non-magnetic support matrix (not shown) made of polyoxymethylene (POM) having the following dimensions: 115 mm × 115 mm × 12 mm.

[0177]

[0167] During magnetic orientation, the substrate (320) supporting the coating layer (310) is arranged on the non-magnetic support plate made of the above POM with the coating layer (310) facing the environment to form an assembly. The non-magnetic support plate (340) has the following dimensions: 180 mm × 130 mm × 2 mm, and the coating layer (310) includes an opening (48 mm × 48 mm) centered and aligned facing the magnetic field generating device (300). The assembly was moved back and forth as described in Table 5 in the vicinity of and above the magnetic field generating device (300) at a distance of about 2 mm from the upper surface of the device.

[0178] Magnetic field generating device for uniaxial orientation

[0168] The magnetic field generating device used to orient at least a portion of the magnetic or magnetizable pigment particles in a uniaxial direction includes a rod-shaped dipole magnet having a length of about 30 mm, a width of about 24 mm, and a thickness of about 6 mm. The rod-shaped dipole magnet is made of POM and is embedded in a matrix having the following dimensions: 40 mm × 40 mm × 15 mm. The N-S magnetic axis of the rod-shaped dipole magnet was parallel to the surface of the substrate (x20) and parallel to the width. The rod-shaped dipole magnet was made of NdFeB N42.

[0179]

[0169] During magnetic orientation, the substrate (x20) supporting the coating layer (x10) is arranged on the non-magnetic support plate made of the above POM with the coating layer (x10) facing the environment to form an assembly. The assembly was placed in the vicinity of and above the magnetic field generating device such that the substrate (x20) was at a distance of about 6 mm from the upper surface of the surface of the rod-shaped dipole magnet.

[0180] Regarding the method shown in FIGS. 2A, 2C, and 4C (device for generating magnetic field B2 in FIGS. 2C and 4C), the magnetic field generating device was vertically removed from the surface of the substrate (x20) opposite to the surface supporting the layer (x10) before performing the following steps.

[0181]

[0171] Regarding the method shown in FIGS. 4D and 4E (device for generating magnetic field B2), the assembly was maintained on the magnetic field generating device during the following steps. Inkjet printing of the top coating inkjet printing composition

[0172] The top coating inkjet printing compositions described in Tables 1 to 3 were independently applied by DOD inkjet printing using a Kyocera KJ4A-TA print head (600 dpi) to form a mark having a rectangular shape with the following dimensions: 20 mm × 12 mm.

[0182]

[0173] For Examples E1 to E18 and Comparative Examples C1 to C11, each top coating composition was applied at about 4 g / m 2 .

[0183]

[0174] For Examples E19 to E21 (halftone inkjet printing of the top coating composition), the top coating composition was applied at about 0.4 g / m 2 , about 2.0 g / m 2 , about 4.1 g / m 2 , and about 8.1 g / m 2 respectively (see the photo of the rectangles from top to bottom in FIG. 5E).

[0184] Curing of the coating layer (x10) made of a UV-Vis curable screen printing composition and the mark (x30) made of a top coating inkjet printing composition

[0175] The coating layer (x10) made of the UV-Vis curable screen printing composition and the mark made of the top coating inkjet printing composition described in Tables 1 to 3 were cured for about 0.5 seconds using a Phoseon (type FireLine, 125 × 20 mm, 395 nm, 8 W / cm 2) was cured by exposure to a UV-LED lamp.

[0185]

[0176] A coating layer (x10) composed of the UV-Vis curable screen printing composition of Comparative Example C11 was exposed to a UV-LED lamp of Phoseon (type FireLine, 125×20 mm, 395 nm, 8 W / cm 2 ) for about 0.5 seconds and cured, and a mark composed of the top coating inkjet printing composition of C11 was cured by exposure to a curing device for about 0.7 seconds (two lamps: an iron-doped mercury lamp of IST Metz, 200 W / cm 2 + mercury lamp 200 W / cm 2 ).

[0186]

[0177] Photographs of the optical effect layers obtained by the method according to the present invention and the comparative method are shown in FIGS. 5A to E at two different viewing angles (left -30°C; right +30°C) (FIG. 5A corresponds to the example in Table 5A; FIG. 5B corresponds to the example in Table 5B; FIG. 5C corresponds to the example in Table 5C; FIG. 5D corresponds to Examples E17 in Table 5B and E18 in Table 5C; 5E corresponds to Examples E19 to E21 in Table 5B, and the top coating is printed in halftone).

[0187]

[0178] The comparative method shown in FIG. 4A for preparing Examples (C1 and C6) lacks the step of magnetically orienting at least a part of the magnetic or magnetizable pigment particles, and provides an optical effect layer having irregularly oriented particles without showing one or more marks. The optical effect layer obtained by a method lacking the step of exposing the coating layer (x10) to the magnetic field of a magnetic field generating device in order to orient at least a part of the particles before the step of applying the top coating composition on the coating layer (x10) in the form of one or more marks (x30) does not show one or more marks.

[0188]

[0179] A method of preparing examples (C2 and C7) that performs a step of magnetically orienting at least a portion of magnetic or magnetizable pigment particles after an inkjet printing step (i.e., a method lacking a step of at least partially curing after the inkjet printing step) provides an optical effect layer having particles oriented in a biaxial direction having both an X-axis and a Y-axis substantially parallel to the substrate surface without showing any marks. To orient at least a portion of the particles, the step of exposing the coating layer (x10) to the magnetic field of a magnetic field generating device is performed after the step of applying the top coating composition in the form of one or more marks (x30) onto the coating layer (x10) without an intermediate step of at least partially curing the top coating composition. The optical effect layer obtained by this method does not show one or more marks.

[0189]

[0180] A method of preparing examples (C3, C4, C8, and C9) that performs a step of magnetically orienting at least a portion of magnetic or magnetizable pigment particles in a biaxial direction before the inkjet printing step and then performs a step of magnetically reorienting the particles in a uniaxial direction (i.e., a method lacking a step of at least partially curing after the inkjet printing step) provides an optical effect layer having particles oriented in a biaxial direction showing a rolling bar when tilting the OEL without showing any marks. After the step of applying the top coating composition in the form of one or more marks (x30) onto the coating layer (x10) without an intermediate step of at least partially curing, the step of exposing the coating layer (x10) to the magnetic field of a magnetic field generating device to orient at least a portion of the particles is not performed after the step of applying the top coating composition. The optical effect layer obtained by this method does not show one or more marks.

[0190]

[0181] Example (C5 and C10) of performing the step of magnetically uniaxially orienting at least a portion of the magnetic or magnetizable pigment particles simultaneously with the inkjet printing step and simultaneously with the step of at least partially curing, the comparative method shown in FIG. 4E for preparing (i.e., a method lacking the step of at least partially curing after the inkjet printing step, or a method including the step of orienting at least a portion of the magnetic or magnetizable pigment particles simultaneously with or after the inkjet printing step) provided an optical effect layer having uniaxially oriented particles showing a rolling bar when tilting the OEL without showing any marks. To orient at least a portion of the particles, the step of exposing the coating layer (x10) to the magnetic field of the magnetic field generating device, partially simultaneously with the step of applying a top coating composition on the coating layer (x10) in the form of one or more marks (x30), and simultaneously with the step of at least partially curing, the obtained optical effect layer does not show one or more marks.

[0191]

[0182] The comparative method shown in FIG. 4F for preparing Example C11, in which the magnetic or magnetizable pigment particles are oriented and fixed by curing before the inkjet printing step, resulted in an optical effect layer showing a rolling bar when tilting the OEL without showing any marks.

[0192]

[0183] Contrary to Examples (C1 - C11) prepared by the comparative methods shown in FIGS. 4A - 4F, Examples (E1 - E18) prepared by the method according to the present invention shown in FIGS. 2A - 2C showed not only prominent effects but also one or more marks described herein.

[0193]

[0184] The method according to the invention shown in Figure 2B for preparing examples (E1 - E4, E7 - E9, E12 - E14, and E17 - 18) which performs the step of magnetically biaxially orienting at least a part of the magnetic or magnetizable pigment particles before the inkjet printing step and then performs the step of at least partially curing the coating layer (x10) and one or more marks (x30) provides an optically effective layer having particles biaxially oriented in a direction substantially parallel to the surface of the substrate (x20) and having both the X - axis and the Y - axis indicating the marks. The optically effective layer thus provided had highly reflective areas that shone like the marks.

[0194]

[0185] The method according to the invention shown in Figure 2C for preparing examples (E5, E10, and E15) which performs two magnetic orientation steps before the inkjet printing step (i.e., performs a second step of magnetically re - orienting at least a part of the magnetic or magnetizable pigment particles uniaxially after a first step of magnetically biaxially orienting at least a part of the particles) and then performs the step of at least partially curing the coating layer (x10) and one or more marks (x30) shows a rolling bar when tilting the OEL and provides an optically effective layer having particles biaxially oriented in a direction indicating the marks. The optically effective layer thus provided had highly reflective areas that shone like the marks.

[0195]

[0186] The method according to the invention shown in Figure 2A for preparing examples (E6, E11, and E16) which performs the step of magnetically uniaxially orienting at least a part of the magnetic or magnetizable pigment particles before the inkjet printing step and then performs the step of at least partially curing the coating layer (x10) and one or more marks (x30) shows a rolling bar when tilting the OEL and provides an optically effective layer having particles uniaxially oriented in a direction indicating the marks.

[0196] As shown in FIGS. 5A - E, the combination of UV - Vis curable screen printing compositions containing magnetic or magnetizable pigment particles may be a cationic curable composition, a radical curable composition, or a hybrid composition for producing a coating layer (x10) with a top - coating inkjet printing composition for producing one or more marks by the method according to the invention, enabling the preparation of an optical effect layer showing one or more marks, and the OEL may be made on different types of substrates.

Claims

Claim 1 A method of fabricating an optical effect layer (OEL) that exhibits one or more marks (x30) on a substrate (x20), comprising: a) applying a radiation-curable coating composition containing non-spherical magnetic or magnetizable pigment particles onto the surface of the substrate (x20), wherein the radiation-curable coating composition is in a first liquid state for forming a coating layer (x10); b) exposing the coating layer (x10) to a magnetic field of a magnetic field generating device to orient at least a portion of the magnetic or magnetizable pigment particles; c) after step b), applying a top coating composition onto the coating layer (x10), wherein the top coating composition is applied in the form of one or more marks (x30); d) at least partially curing the coating layer (x10) and the one or more marks (x30) with a curing device (x50), either partially simultaneously with or after step c). A method as described above. Claim 2 The method according to claim 1, wherein step b) of exposing the coating layer (x10) is performed to orient at least a portion of the non-spherical magnetic or magnetizable pigment particles in a uniaxial direction. Claim 3 The method according to claim 1, wherein step b) of exposing the coating layer (x10) is performed to orient at least a portion of the non-spherical magnetic or magnetizable pigment particles in a biaxial direction, and the non-spherical magnetic or magnetizable pigment particles are platelet-shaped magnetic or magnetizable pigment particles having an X-axis and a Y-axis that define a major plane of extension of the particles. Claim 4 The method according to claim 3, wherein step b) of exposing the coating layer (x10) is performed to orient at least a portion of the platelet-shaped magnetic or magnetizable pigment particles in a biaxial direction such that both their X-axis and Y-axis are substantially parallel to the substrate surface. Claim 5 Step b) consists of two steps. A first step b1) consists of exposing the coating layer (x10) to the magnetic field of the magnetic field generating device in order to orient at least some of the platelet-shaped magnetic or magnetizable pigment particles in a biaxial direction. A further step b2) consists of exposing the coating layer (x10) to the magnetic field of a second magnetic field generating device in order to orient at least some of the platelet-shaped magnetic or magnetizable particles in a uniaxial direction. The further step b2) is carried out partially simultaneously with, simultaneously with, or after step b1). The method according to claim 3 or 4.

6. Step x) of selectively at least partially curing one or more first areas of the coating layer (x10) so that one or more second areas of the coating layer (x10) remain unexposed to irradiation, in order to fix at least some of the magnetic or magnetizable particles in their adopted positions and orientations; Step y) of exposing the coating layer (x10) to the magnetic field of a second magnetic field generating device; further comprising; Step x) is carried out partially simultaneously with or after step c), and step y) is carried out after step x) and partially simultaneously with or before step d). The method according to any one of claims 1 to 4.

7. Step x) of selectively at least partially curing one or more first areas of the coating layer (x10) so that one or more second areas of the coating layer (x10) remain unexposed to irradiation, in order to fix at least some of the magnetic or magnetizable particles in their adopted positions and orientations; Step y) of exposing the coating layer (x10) to the magnetic field of a third magnetic field generating device; further comprising; Step x) is carried out partially simultaneously with or after step c), and step y) is carried out after step x) and partially simultaneously with or before step d). The method according to claim 5.

8. Step x) of selectively and at least partially curing one or more first areas of the coating layer (x10) so that one or more second areas of the coating layer (x10) remain unexposed, thereby fixing at least some of the magnetic or magnetizable particles in their employed positions and orientations; Step y) of exposing the coating layer (x10) to the magnetic field of a second magnetic field generating device; further comprising; The method according to any one of claims 1 to 4, wherein step x) is carried out partially simultaneously with or after step b), and step y) is carried out after step x) and before step c).

9. Step x) of selectively and at least partially curing one or more first areas of the coating layer (x10) so that one or more second areas of the coating layer (x10) remain unexposed, thereby fixing at least some of the magnetic or magnetizable particles in their employed positions and orientations; Step y) of exposing the coating layer (x10) to the magnetic field of a third magnetic field generating device; further comprising; The method according to claim 5, wherein step x) is carried out partially simultaneously with or after step b), and step y) is carried out after step x) and before step c).

10. The method according to any one of claims 1 to 9, wherein step a) of applying the radiation curable coating composition is carried out by a process selected from the group consisting of screen printing, gravure printing, pad printing, and flexographic printing.

11. The method according to any one of claims 1 to 10, wherein step c) of applying the top coating composition is carried out by non-contact fluid microdispensing technology.

12. The method according to claim 11, wherein the non-contact fluid microdispensing technology is an inkjet printing process.

13. The method according to any one of claims 1 to 12, wherein at least some of the non-spherical magnetic or magnetizable particles are constituted by non-spherical optically variable magnetic or magnetizable pigment particles.

14. The method according to claim 13, wherein the non-spherical optically variable magnetic or magnetizable pigment particles are selected from the group consisting of magnetic thin film interference pigments, magnetic cholesteric liquid crystal pigments, and mixtures thereof.

15. The method according to any one of claims 1 to 14, wherein the one or more marks are selected from the group consisting of codes, symbols, alphanumeric symbols, motifs, geometric patterns, characters, words, numbers, logos, figures, portraits, and combinations thereof.

Images