Security document or article comprising an optical effect layer containing magnetic or magnetisable pigment particles and method for producing said optical effect layer

Abstract

The present invention relates to the field of protecting security documents, such as banknotes and identity cards, against counterfeiting and illegal duplication. In particular, the present invention provides security documents and decorative articles comprising one or more optical effect layers (OELs), and methods for producing said OELs, ​​which comprise magnetically oriented platelet-shaped magnetic or magnetizable pigment particles in an at least partially cured coating layer (x10), exhibiting eye-catching optical effects, such that an observer can easily authenticate the OEL when tilted at a viewing / observation angle of about -45° to about +45°.

Description

FIELD OF THE INVENTION

[0001]

[0001] The present invention relates to the field of optical effect layers (OELs) comprising magnetically oriented magnetic or magnetisable pigment particles. In particular, the present invention provides security documents and decorative articles comprising one or more optical effect layers (OELs), as well as methods for producing said OELs and the use of said OELs as an anti-counterfeiting measure for security documents or security articles and for decorative purposes. BACKGROUND OF THE INVENTION

[0002] The use of inks, compositions, coatings, or layers containing oriented magnetic or magnetizable pigment particles, particularly optically variable magnetic or magnetizable pigment particles, for the manufacture of security elements, for example in the field of security documents, is known in the art. Coatings or layers containing oriented magnetic or magnetizable pigment particles are disclosed, for example, in U.S. Pat. Nos. 2,570,856; 3,676,273; 3,791,864; 5,630,877; and 5,364,689. Coatings or layers containing oriented magnetic color-shifting pigment particles, which produce particularly attractive optical effects useful for protecting security documents, are disclosed in WO 2002 / 090002 and WO 2005 / 002866.

[0003]

[0003] Security features, e.g., for security documents, can generally be categorized into "covert" security features, on the one hand, and "overt" security features, on the other hand. The protection offered by covert security features relies on the principle that such features are difficult to detect, typically requiring specialized equipment and knowledge for detection. In contrast, "overt" security features rely on the concept of being easily detectable by the naked eye; for example, such features may be detectable by sight and / or touch, but remain difficult to create and / or copy. However, the effectiveness of an overt security feature depends heavily on its recognizability as a security feature.

[0004]

[0004] Magnetic or magnetizable pigment particles in printing inks or coatings allow for the generation of magnetically induced images, designs, and / or patterns through the application of a corresponding structured magnetic field, inducing local orientation of the magnetic or magnetizable pigment particles in the as-yet-cured / uncured (i.e., wet) coating, followed by curing of the coating, resulting in a fixed and stable magnetically induced image, design, or pattern. Materials and techniques for orienting magnetic or magnetizable pigment particles in coating compositions are disclosed, for example, in U.S. Pat. No. 2,418,479, U.S. Pat. No. 2,570,856; U.S. Pat. No. 3,791,864, DE 2006848 A1, U.S. Pat. No. 3,676,273, U.S. Pat. No. 5,364,689, U.S. Pat. No. 6,103,361, EP 0406667; U.S. Pat. Appl. Publ. No. 2002 / 0160194; U.S. Pat. Appl. Publ. No. 2004 / 0009308; EP 0710508; WO 2002 / 09002; WO 2003 / 000801; WO 2005 / 002866; WO 2006 / 061301. In this way, magnetic induction patterns can be generated that are highly resistant to counterfeiting.The security elements in question can only be produced by having access to both magnetic or magnetizable pigment particles or the corresponding inks, and the specific technology used to print said inks and orient said pigments within the printed inks.

[0005]

[0005] It is known in the art that high contrast, brightness, and reflectivity are essential for overt security features comprising magnetically oriented pigments or particles, as described, for example, in International Publication No. 2015 / 018663.

[0006]

[0006] Depending on the magnetic orientation pattern of the magnetic or magnetizable pigment particles in an optical effect layer (OEL) and depending on the viewing direction, the OEL can display light and dark areas. The optical properties of a particular zone of an OEL depend directly on the orientation of the magnetic or magnetizable pigment particles within the coating layer that forms the OEL.

[0007] EP 2484455 discloses an OEL comprising jointly visible zones of first and second cured coating compositions comprising pigment particles oriented to mimic first and second curved surfaces. As disclosed in EP 2484455 and the prior art cited in

[0003] , particularly WO 2004 / 007095, coating compositions comprising pigment particles oriented to mimic curved surfaces produce specularly reflective zones that appear to an observer as bright zones that move when the substrate supporting the coating compositions is tilted (i.e., when the viewing direction is changed).

[0008]

[0008] EP 2846932 discloses an OEL with platelet-shaped magnetic or magnetizable pigment particles oriented to display a pattern of bright and dark areas that appear to move or appear and disappear as the viewing angle of the optical effect layer is changed.

[0046] As disclosed in

[0046] , the particles, based on their shape, have maximum reflectivity (largest projected area) in the direction perpendicular to the extended surface; therefore, in orthogonal views, in the image of the OEL, bright areas correspond to particles whose orientation nearly matches that of the surface. That is, they correspond to particles that have a small angle θ with respect to the surface of the OEL, so that incident light is reflected in substantially the same (orthogonal) direction.

[0009]

[0009] In the field of authenticating overt security elements comprising magnetically oriented platelet-shaped magnetic or magnetisable pigment particles, an observer tilts said security element from the normal direction (i.e., a viewing direction perpendicular to the surface of the substrate supporting the security element) to a grazing angle (i.e., a viewing direction substantially parallel to the surface of the substrate), i.e., from ±90°, in order to verify its authenticity. However, non-expert observers, even if trained on security elements, typically tilt security elements within a narrow range not exceeding ±45° from the normal to the substrate on which the security element resides. Furthermore, people on the street do not always benefit from optimal lighting conditions for the inspection / authentication of security elements.

[0010]

[0010] Prior art documents do not provide information regarding the orientation and appropriate elevation angle of the magnetically oriented particles, producing OELs that exhibit significant and observable variations in brightness (i.e., increases and decreases) when tilted by an observer in the process of conventionally authenticating the element.

[0011]

[0011] Therefore, there remains a need for an optical effect layer (OEL) and a method for producing said OEL, which exhibits an eye-catching and easily recognizable visual appearance by exhibiting highly contrasting highly reflective (light) and non-reflective (dark) areas at viewing angles suitable for a street person, so that the OEL can be easily authenticated. Summary of the Invention

[0012] SUMMARY OF THE INVENTION It is therefore an object of the present invention to overcome the deficiencies of the prior art.

[0013] This is achieved by providing a security document or decorative article comprising a substrate (x20) having a two-dimensional surface and one or more optical effect layers (OEL) on said substrate (x20), said one or more optical effect layers (OEL) having a major axis X and comprising magnetically oriented platelet-shaped magnetic or magnetizable pigment particles in an at least partially cured coating layer (x10), the orientation of the platelet-shaped pigment particles is defined by a platelet vector, which is a vector parallel to the particle's main axis X, the platelet vectors of adjacent platelet-shaped magnetic or magnetizable pigment particles being substantially parallel to each other; the platelet vector of the platelet-shaped magnetic or magnetizable pigment particle is angled at an elevation angle γ with respect to the two-dimensional surface (x20) of the substrate at the location of the particle, said elevation angle γ being greater than 0° and less than 30° (0°<γ<30°) or greater than 150° and less than 180° (150°<γ<180°), preferably between about 5° and less than 30° (5°≦γ<30°) or greater than 150° and less than about 175° (150°<γ≦175°), more preferably between about 5° and about 25° (5°≦γ≦25°) or between about 155° and about 175° (155°≦γ≦175°); Thereby, the optical effect layer(s) (OEL) exhibit an increase in luminance reaching a luminance maximum and a decrease in luminance within a viewing angle of -45° to +45° of the substrate (x20).

[0014]

[0014] The optical effect layer(s) (OEL) described herein comprise uniaxially oriented platelet-shaped magnetic or magnetizable pigment particles or comprise biaxially oriented platelet-shaped magnetic or magnetizable pigment particles.

[0015]

[0015] Also described in this specification is a security document or article as described herein, further comprising one or more indicia, said one or more indicia being present between the substrate (x20) and one or more optical effect layers (OEL).

[0016]

[0016] Also provided herein is a security document or article, wherein the one or more optical effect layers (OEL) comprise magnetically oriented platelet-shaped magnetic or magnetisable pigment particles in an at least partially cured coating layer (x10) and magnetically oriented second platelet-shaped magnetic or magnetisable pigment particles in an at least partially cured second coating layer (x11), wherein the at least partially cured second coating layer (x11) at least partially or completely overlaps the at least partially cured coating layer (x10), or the at least partially cured second coating layer (x11) overlaps the at least partially cured coating layer (x10) or Also described are security documents or articles comprising a second coating layer (x10) adjacent to or spaced apart from the at least partially cured coating layer (x10) an at least partially cured second coating layer (x11), wherein the platelet vectors of the second platelet-shaped magnetic or magnetisable pigment particles are angled at the location of the particles in the at least partially cured second coating layer (x11) by a further elevation angle γ' relative to the two-dimensional surface of the substrate (x20) at the location of the particles, wherein the further elevation angle γ' is greater than 0° and less than 30° (0°<γ'<30°) or greater than 150° and less than 180° (150°<γ'<180°), and wherein said elevation angle γ and the further elevation angle γ' are different from each other and / or are not coplanar.

[0017] Also described herein are methods for producing the optical effect layers (OELs) described herein, and the optical effect layers (OELs) obtained thereby. Also described herein is a method for producing an optical effect layer (OEL) on a substrate (x20) having a two-dimensional surface, said method comprising: a) applying a radiation-curable coating composition comprising platelet-shaped magnetic or magnetizable pigment particles onto a surface of a substrate (x20), said radiation-curable coating composition being in a first liquid state to form a coating layer (x10); b) exposing the coating layer (x10) to a magnetic field of a magnetic field generator (x30) in one or more areas where the magnetic field is substantially uniform, so as to orient at least a portion of the platelet-shaped magnetic or magnetizable pigment particles, wherein a substrate (x20) supporting the coating layer (x10) is provided in the one or more areas where the magnetic field is substantially uniform, and the angle α between the tangent of the magnetic field lines of the magnetic field within the magnetic field is greater than 0° and less than 30° (0°<α<30°) or greater than 150° and less than 180° (150°<α<180°), preferably greater than 5° and less than 30° (5°≦α<30°) or greater than 150° and less than 175° (150°<α≦175°), more preferably within the range of about 5° to about 25° (5°≦α≦25°) or about 155° to about 175° (155°≦α≦175°); c) partially simultaneously with step b) or after step b), at least partially curing the coating layer (x10) in a curing unit (x40) so as to at least partially fix the position and orientation of the platelet-shaped magnetic or magnetizable pigment particles in the coating layer (x10) and to produce an at least partially cured coating layer (x10); Including, The orientation of the platelet-shaped pigment particles is defined by a platelet vector, which is a vector parallel to the particle's main axis X, the platelet vectors of adjacent platelet-shaped magnetic or magnetizable pigment particles being substantially parallel to each other, and the platelet vectors of the platelet-shaped magnetic or magnetizable pigment particles being angled by an elevation angle γ with respect to the two-dimensional surface of the substrate (x20) at the particle's location, said elevation angle γ being greater than 0° and less than 30° (0°<γ<30°) or greater than 150° and less than 180° (150°<γ<180°).

[0018]

[0018] Step b) of exposing a coating layer (x10) as described herein is performed to uniaxially orient at least a portion of the platelet-shaped magnetic or magnetizable pigment particles such that the platelet vectors of adjacent platelet-shaped magnetic or magnetizable pigment particles are substantially parallel to one another. Alternatively, step b) of exposing a coating layer (x10) as described herein may be performed to biaxially orient at least a portion of the platelet-shaped magnetic or magnetizable pigment particles having a major axis X and a second major axis Y as described herein, the orientation being further defined by a second platelet vector being a vector parallel to the second major axis Y of the particles, whereby the platelet vectors of adjacent platelet-shaped magnetic or magnetizable pigment particles are substantially parallel to one another and the second platelet vectors of said adjacent platelet-shaped magnetic or magnetizable pigment particles are substantially parallel to one another.

[0019]

[0019] Also described herein is a method for producing an optical effect layer (OEL) comprising an at least partially cured coating layer (x10) comprising platelet-shaped magnetic or magnetisable pigment particles and an at least partially cured second coating layer (x11) comprising second platelet-shaped magnetic or magnetisable pigment particles, said at least partially cured second coating layer (x11) may be at least partially or completely on said at least partially cured coating layer (x10), or adjacent to said at least partially cured coating layer (x10), or may be spaced apart from said at least partially cured coating layer (x10), The orientation of each of the platelet-shaped pigment particles is defined by a platelet vector, which is a vector parallel to the major axis X of the second platelet-shaped pigment particle, wherein the platelet vectors of adjacent second platelet-shaped magnetic or magnetizable pigment particles are substantially parallel to each other, and wherein the platelet vectors of the second platelet-shaped magnetic or magnetizable pigment particles are angled by a further elevation angle γ' with respect to the two-dimensional surface of the substrate (x20) at the particle's location, wherein the further elevation angle γ' is greater than 0° and less than 30° (0°<γ'<30°) or greater than 150° and less than 180° (150°<γ'<180°), and wherein said elevation angle γ and the further elevation angle γ' are different from each other and / or are not coplanar.

[0020]

[0020] The present invention provides an optical effect layer (OEL) comprising magnetically oriented magnetic or magnetizable pigment particles with a specific elevation angle that exhibits highly contrasting highly reflective (bright) and non-reflective (dark) areas upon changing tilt angle by a passerby and under diffuse lighting conditions without requiring complex manipulation. Thus, the OEL described herein can be easily authenticated by a passerby.

[0021]

[0021] We will now describe in more detail, with reference to the drawings and specific embodiments, the security document or article comprising one or more optical effect layers (OELs) described in the specification, and the method described herein for producing said OELs on a substrate (x20). [Brief explanation of the drawings]

[0022] [Figure 1] 1 shows a schematic front view of an OEL as seen by a street person, who tilts the OEL around a tilt axis τ at an observation angle between −45° and +45° to easily authenticate the OEL on a substrate having a two-dimensional surface. [Figure 2A] Schematically shown is a platelet-shaped particle having major axis X and major axis Y. [Figure 2B] Schematically shows uniaxially oriented platelet-shaped particles, where the platelet vectors (vectors parallel to the particle's major axis X) of adjacent platelet-shaped magnetic or magnetisable pigment particles are substantially parallel to each other. [Figure 2C] 1 shows a schematic representation of biaxially oriented platelet-shaped particles, wherein the platelet vectors (vectors parallel to the particle's major axis X) of adjacent platelet-shaped magnetic or magnetizable pigment particles are substantially parallel to each other, and the second platelet vectors (vectors parallel to the particle's major axis Y) of adjacent platelet-shaped magnetic or magnetizable pigment particles are substantially parallel to each other. [Figure 3A] Schematically shows a cross section of an OEL comprising magnetically oriented platelet-shaped magnetic or magnetisable pigment particles in a coating layer (310) on a substrate (320). [Figure 3B]1 shows a schematic cross-section (cross-section along a plane perpendicular to the tilt axis τ of the OEL) of an OEL comprising a single at least partially cured coating layer (310) comprising platelet-shaped magnetic or magnetizable pigment particles in one or more first zones (310-a) and platelet-shaped magnetic or magnetizable pigment particles in one or more second zones (310-b), wherein substantially all of the platelet-shaped magnetic or magnetizable pigment particles in one or more zones (310-a) have substantially the same elevation angle γ and substantially all of the platelet-shaped magnetic or magnetizable pigment particles in one or more zones (310-b) have substantially the same further elevation angle γ', said elevation angle γ and further elevation angle γ' being different from each other and / or not coplanar. [Figure 3C] 1 shows a schematic cross-section of an OEL comprising an at least partially cured coating layer (310) incorporating magnetically oriented platelet-shaped magnetic or magnetizable pigment particles and an at least partially cured second coating layer (311) incorporating second platelet-shaped magnetic or magnetizable pigment particles, said at least partially cured second coating layer (311) partially overlapping the at least partially cured coating layer (310), wherein substantially all of the platelet-shaped magnetic or magnetizable pigment particles in the at least partially cured coating layer (310) have substantially the same further elevation angle γ and substantially all of the second platelet-shaped magnetic or magnetizable pigment particles in the at least partially cured second coating layer (311) have substantially the same further elevation angle γ', said elevation angle γ and further elevation angle γ' being different from each other and / or not coplanar. [Figure 3D]1 shows a schematic cross-section of an OEL comprising an at least partially cured coating layer (310) incorporating magnetically oriented platelet-shaped magnetic or magnetizable pigment particles and an at least partially cured second coating layer (311) incorporating second platelet-shaped magnetic or magnetizable pigment particles, said at least partially cured second coating layer (311) completely overlapping the at least partially cured coating layer (310), wherein all platelet-shaped magnetic or magnetizable pigment particles in the at least partially cured coating layer (310) have substantially the same further elevation angle γ and all second platelet-shaped magnetic or magnetizable pigment particles in the at least partially cured second coating layer (311) have substantially the same further elevation angle γ', said elevation angle γ and further elevation angle γ' being different from each other and / or not coplanar. [Figure 3E] 1 shows a schematic representation of a cross section of an OEL comprising an at least partially cured coating layer (310) incorporating magnetically oriented platelet-shaped magnetic or magnetizable pigment particles and an at least partially cured second coating layer (311) incorporating second platelet-shaped magnetic or magnetizable pigment particles, said at least partially cured second coating layer being adjacent to the at least partially cured coating layer (310), wherein all platelet-shaped magnetic or magnetizable pigment particles in the at least partially cured coating layer (310) have substantially the same further elevation angle γ and all second platelet-shaped magnetic or magnetizable pigment particles in the at least partially cured second coating layer (311) have substantially the same further elevation angle γ', said elevation angle γ and further elevation angle γ' being different from each other and / or not coplanar. [Figure 4A1]1 shows a schematic cross-section of a magnetic field generating device (430) suitable for uniaxially orienting platelet-shaped magnetic or magnetizable pigment particles in a coating layer (410) on a substrate (420), said device (430) comprising a bar dipole magnet, said platelet-shaped magnetic or magnetizable pigment particles being exposed to the magnetic field (magnetic field lines shown as lines with arrows pointing from north pole to south pole) of said magnetic field generating device (430) in one region (shown as a dotted rectangle A) where the magnetic field is substantially uniform, and said substrate (420) supporting the coating layer (410) is positioned at an angle α to said region A. [Figure 4A2] Schematic representation of a magnetic field generating device (430) suitable for uniaxially orienting platelet-shaped magnetic or magnetizable pigment particles in a coating layer (410) on a substrate (420), said device (430) consisting of two bar dipole magnets (M1, M2) with the same magnetic direction and an iron yoke (Y), wherein the platelet-shaped magnetic or magnetizable pigment particles are exposed to the magnetic field of the magnetic field generating device (430) in one region (shown as a dotted rectangle A) where the magnetic field is substantially uniform (the magnetic field lines are shown as lines with arrows pointing from the north pole to the south pole), and wherein the substrate (420) supporting the coating layer (410) is positioned in said region A at a specific angle α. [Figure 4B1] Schematic representation of a magnetic field generating device (430) (left) suitable for biaxially orienting at least a portion of platelet-shaped magnetic or magnetizable pigment particles in a coating layer (410) on a substrate (420) and a cross section (right) of said device (430), said device (430) consisting of a linear arrangement of four dipole magnets (M1-M4) arranged in a staggered or zigzag pattern, said platelet-shaped magnetic or magnetizable pigment particles being exposed to the magnetic field (magnetic field lines shown as lines with arrows pointing from north pole to south pole) of the magnetic field generating device (430) in one region (shown as dotted rectangles A and A') where the magnetic field is substantially uniform, and said substrate (420) supporting the coating layer (410) being arranged at an angle α in said region A (or alternatively in region A'). [Figure 4B2]Schematic representation of a magnetic field generating device (430) (left) suitable for biaxially orienting at least a portion of platelet-shaped magnetic or magnetizable pigment particles in a coating layer (410) on a substrate (420) and a cross section (right) of said device (430), said device (430) consisting of two dipole magnets (M1, M2) with opposite magnetic directions, wherein the platelet-shaped magnetic or magnetizable pigment particles are exposed to the magnetic field (magnetic field lines shown as lines with arrows pointing from north pole to south pole) of the magnetic field generating device (430) in one region (shown as dotted rectangles A and A') where the magnetic field is substantially uniform, and wherein the substrate (420) supporting the coating layer (410) is provided in said region A (or alternatively in region A') at an angle α. [Figure 4B3] Schematic representation of a magnetic field generating device (430) (left) suitable for biaxially orienting at least a portion of platelet-shaped magnetic or magnetizable pigment particles in a coating layer (410) on a substrate (420) and a cross section (right) of said device (430), said device (430) consisting of two dipole magnets (M1, M2) with the same magnetic direction, wherein the platelet-shaped magnetic or magnetizable pigment particles are exposed to the magnetic field (magnetic field lines shown as lines with arrows pointing from north pole to south pole) of the magnetic field generating device (430) in one region (shown as a dotted rectangle A) where the magnetic field is substantially uniform, and wherein the substrate (420) supporting the coating layer (410) is arranged in said region A at an angle α. [Figure 4B4] Schematic representation of a magnetic field generating device (430) (left) suitable for biaxially orienting at least a portion of platelet-shaped magnetic or magnetizable pigment particles in a coating layer (410) on a substrate (420) and a top view (right) of said device (430), said device (430) consisting of a Halbach array with five dipole magnets (M1-M5), wherein the platelet-shaped magnetic or magnetizable pigment particles are exposed to the magnetic field (magnetic field lines shown as lines with arrows pointing from north pole to south pole) of the magnetic field generating device (430) in one region (shown as a dotted rectangle A) where the magnetic field is substantially uniform, and the substrate (420) supporting the coating layer (410) is positioned in said region A at an angle α. [Figure 4B5]1 shows a schematic cross-section of a magnetic field generating device (430) suitable for biaxially orienting at least a portion of platelet-shaped magnetic or magnetizable pigment particles in a coating layer (410) on a substrate (420), the device (430) consisting of a Halbach cylinder assembly comprising four structures, each comprising a magnet bar (M1-M4) surrounded by a magnet wire coil (not shown), the platelet-shaped magnetic or magnetizable pigment particles are exposed to the magnetic field (magnetic field lines shown as lines with arrows pointing from north pole to south pole) of the magnetic field generating device (430) in one region (shown as a dotted rectangle A) where the magnetic field is substantially uniform, and the substrate (420) supporting the coating layer (410) is arranged in said region A at an angle α. [Figure 4B6] 1 shows a schematic representation of a magnetic field generating device (430) (left) suitable for biaxially orienting at least a portion of platelet-shaped magnetic or magnetizable pigment particles in a coating layer (410) on a substrate (420) and a top view (right) of said device (430), said device (430) consisting of an assembly of eight bar dipole magnets (M1-M8), said assembly comprising a first set comprising a first bar dipole magnet (M4) and two bar dipole magnets (M1, M6), and a second set comprising a first bar dipole magnet (M5). and a second set comprising two second bar dipole magnets (M3; M8) and a first pair of third bar dipole magnets (M2, M7), wherein the platelet-shaped magnetic or magnetizable pigment particles are exposed to the magnetic field (magnetic field lines shown as lines with arrows pointing from north pole to south pole) of a magnetic field generator (430) in one area (shown as a dotted rectangle A) where the magnetic field is substantially uniform, and a substrate (420) supporting a coating layer (410) is provided in said area A at an angle α. [Figure 5A1]5A1 and 5A2-5A3 are schematic diagrams showing a perspective view (FIG. 5A1) and cross-sectional views (FIGS. 5A2-5A3) of a magnetic field generating device (530) and a curing device (540) suitable for biaxially orienting platelet-shaped magnetic or magnetizable pigment particles contained in a coating layer (510) on a substrate (520). The magnetic field generator (530) comprises nine bar dipole magnets (M1 to M9) arranged in a row with alternating N-S magnetic directions, the platelet-shaped magnetic or magnetizable pigment particles are exposed to the magnetic field of the magnetic field generator (530) in one area (shown as a dotted parallelepiped A) where the magnetic field is substantially uniform (for illustrative purposes, magnets M3 to M9 are shown in Figure 5A2, with magnetic field lines shown as lines with arrows pointing from N pole to S pole), and the substrate (520) supporting the coating layer (510) is provided in said area A at an angle α, and Figure 5A3 shows the process in which at least a partial curing step by a curing device (540) is partially carried out simultaneously with the magnetic orientation step. [Figure 5A2] 5A1 and 5A2-5A3 are schematic diagrams showing a perspective view (FIG. 5A1) and cross-sectional views (FIGS. 5A2-5A3) of a magnetic field generating device (530) and a curing device (540) suitable for biaxially orienting platelet-shaped magnetic or magnetizable pigment particles contained in a coating layer (510) on a substrate (520). The magnetic field generator (530) comprises nine bar dipole magnets (M1 to M9) arranged in a row with alternating N-S magnetic directions, the platelet-shaped magnetic or magnetizable pigment particles are exposed to the magnetic field of the magnetic field generator (530) in one area (shown as a dotted parallelepiped A) where the magnetic field is substantially uniform (for illustrative purposes, magnets M3 to M9 are shown in Figure 5A2, with magnetic field lines shown as lines with arrows pointing from N pole to S pole), and the substrate (520) supporting the coating layer (510) is provided in said area A at an angle α, and Figure 5A3 shows the process in which at least a partial curing step by a curing device (540) is partially carried out simultaneously with the magnetic orientation step. [Figure 5A3]5A1 and 5A2-5A3 are schematic diagrams showing a perspective view (FIG. 5A1) and cross-sectional views (FIGS. 5A2-5A3) of a magnetic field generating device (530) and a curing device (540) suitable for biaxially orienting platelet-shaped magnetic or magnetizable pigment particles contained in a coating layer (510) on a substrate (520). The magnetic field generator (530) comprises nine bar dipole magnets (M1 to M9) arranged in a row with alternating N-S magnetic directions, the platelet-shaped magnetic or magnetizable pigment particles are exposed to the magnetic field of the magnetic field generator (530) in one area (shown as a dotted parallelepiped A) where the magnetic field is substantially uniform (for illustrative purposes, magnets M3 to M9 are shown in Figure 5A2, with magnetic field lines shown as lines with arrows pointing from N pole to S pole), and the substrate (520) supporting the coating layer (510) is provided in said area A at an angle α, and Figure 5A3 shows the process in which at least a partial curing step by a curing device (540) is partially carried out simultaneously with the magnetic orientation step. [Figure 6A] Schematic front view of a magnetic field generator (630) and curing device (640) for uniaxially orienting platelet-shaped magnetic or magnetizable pigment particles contained in a coating layer (610) on a substrate (620). The magnetic field generator (630) comprises two bar dipole magnets (M1, M2) and two magnetic pole pieces (P1, P2) arranged as a rectangular assembly, the platelet-shaped magnetic or magnetizable pigment particles are exposed to the magnetic field of the magnetic field generator (630) in one region (shown as a dotted rectangle A) where the magnetic field is substantially uniform (magnetic field lines shown as lines with arrows pointing from north to south pole), and the substrate (620) supporting the coating layer (610) is positioned in said region A at an angle α. [Figure 6B1] FIG. 6B1 shows a process in which at least a partial curing step is performed partially simultaneously with the magnetic orientation step. [Figure 6B2] FIG. 6B2 shows a process in which at least a partial curing step is performed following the magnetic orientation step. [Figure 7A-1] 5 shows a photographic image of an OEL obtained by using the method and apparatus shown in FIG. [Figure 7A-2] 5 shows a photographic image of an OEL obtained by using the method and apparatus shown in FIG. [Figure 7A-3] 5 shows a photographic image of an OEL obtained by using the method and apparatus shown in FIG. [Figure 7B] Figure 7A shows the luminance curves of an OEL containing biaxially oriented pigment particles with different elevation angles γ. The OEL was printed on a transparent PET substrate placed on a black substrate. The y-axis represents the brightness of the OEL in arbitrary units calculated over a 100x100 pixel area of ​​a photograph of the OEL, and the x-axis represents the observation angle θ. [Figure 8-1] 5 shows a photographic image of an OEL similar to FIG. 3D, comprising biaxially oriented pigment particles, said OEL being obtained by using the method and apparatus shown in FIG. [Figure 8-2] 5 shows a photographic image of an OEL similar to FIG. 3D, comprising biaxially oriented pigment particles, said OEL being obtained by using the method and apparatus shown in FIG. [Figure 9A] 9A-9B show luminance curves for two OELs containing uniaxially oriented pigment particles with an elevation angle γ of approximately 20°, where the OELs are printed on a transparent PET substrate that is placed on a black substrate (FIG. 9A) or a white substrate (FIG. 9B). The y-axis represents the brightness of the OEL in arbitrary units calculated over a 100x100 pixel area of ​​a photograph of the OEL, and the x-axis represents the observation angle θ. [Figure 9B] 9A-9B show luminance curves for two OELs containing uniaxially oriented pigment particles with an elevation angle γ of approximately 20°, where the OELs are printed on a transparent PET substrate that is placed on a black substrate (FIG. 9A) or a white substrate (FIG. 9B). The y-axis represents the brightness of the OEL in arbitrary units calculated over a 100x100 pixel area of ​​a photograph of the OEL, and the x-axis represents the observation angle θ. [Figure 10]7A and 8 show a schematic diagram of an apparatus for taking the photographic images shown in FIG. 7A and FIG. 8 at different observation angles θ, the apparatus comprising an integrating sphere (IS), an illumination source (L), a camera (C), and a movable holder (H) for a sample (S), the camera (C) and the movable holder (H) being fixed on a plate (P) so as to vary the observation angle θ of the sample. DETAILED DESCRIPTION OF THE INVENTION

[0023]

[0022] For illustrative purposes, the magnetic field generating device (x30) shown in the figure Magnetic field The field lines (shown as lines with arrows pointing from north pole to south pole) were obtained by simulation, and the magnetic field simulation was carried out using the software Vizimag 3.19.

[0024] definition The following definitions are to be used to interpret the meaning of terms discussed in this specification and recited in the claims.

[0025]

[0024] As used herein, the term "at least one" is meant to specify one or more, for example, one or two or three.

[0026]

[0025] As used herein, the terms "about" and "substantially" mean that the subject amount or value may be the specified specific value or another value nearby it. Generally, the terms "about" and "substantially" indicating a specific value are intended to indicate a range of ±5% of that value. As an example, the phrase "about 100" indicates a range of 100 ±5, i.e., a range of 95 to 105. Generally, when the term "about" is used, it can be expected that similar results or effects of the present invention can be obtained within a range of ±5% of the indicated value.

[0027] The term "substantially parallel" means that the distance between the 2This refers to an average deviation of 2° or less from parallel alignment over the surface of the coating layer, or over at least about 100 particles.

[0028] 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 "A only, or B only, or both A and B." In the case of "A only," the term encompasses the possibility that B is not present, i.e., "A only and not B."

[0029]

[0028] As used herein, the term "comprises" is intended to be non-exclusive and open-ended. Thus, for example, a coating composition containing compound A may contain compounds other than A. However, the term "comprises" also encompasses the more restrictive meanings of "consisting essentially of" and "consisting of," as specific embodiments thereof. For example, a "mixture containing A, B, and optionally C" may consist (essentially) of A and B, or may consist (essentially) of A, B, and C.

[0030]

[0029] As used herein, the term "optical effect layer (OEL)" means a coating layer comprising oriented magnetic or magnetizable pigment particles, which are oriented by a magnetic field, and which have their orientation and position fixed / frozen (i.e., after curing) to form a magnetically induced image.

[0031] The term "coating composition" refers to any composition that can form an optical effect layer (OEL) on a solid substrate and that can be applied preferably, but not exclusively, by a printing method. The coating composition comprises platelet-shaped magnetic or magnetizable pigment particles as described herein and a binder as described herein.

[0032]

[0031] As used herein, the term "wet" refers to a coating layer that is at least partially uncured, e.g., a coating in which platelet-shaped magnetic or magnetizable pigment particles can still change their position and orientation under the influence of external forces acting on them.

[0033]

[0032] The term "security document" generally refers to a document that is protected against counterfeiting or fraud by at least one security feature. Examples of security documents include, but are not limited to, securities and commodities.

[0034]

[0033] The term "security feature" is used to denote an image, pattern, or graphic element that can be used for authentication purposes.

[0035]

[0034] When this specification refers to "preferred" embodiments / features, combinations of these "preferred" embodiments / features shall also be deemed to be disclosed, so long as this combination of "preferred" embodiments / features makes technical sense.

[0036]

[0035] The present invention provides security documents and decorative articles comprising a substrate (x20) having a two-dimensional surface and one or more optical effect layers (OEL) on said substrate (x20), said OEL being based on magnetically oriented platelet-shaped magnetic or magnetizable pigment particles, the orientation of the substrate (x20) being defined by a substrate vector which is a local normal vector to the substrate (x20) perpendicular to the two-dimensional surface (x20) of the substrate at each position of the one or more optical effect layers (OEL).

[0037]

[0036] Typical examples of decorative articles include, but are not limited to, luxury goods, cosmetic packaging, automotive parts, electronic / electrical appliances, furniture, and nail products. Alternatively, one or more OELs described herein may be provided on a secondary substrate, such as a label, and then transferred to the decorative article in a separate step.

[0038]

[0037] Security documents include, but are not limited to, securities and valuable goods. Typical examples of valuable goods include banknotes, certificates, tickets, checks, vouchers, accounting stamps and tax labels, contracts, etc., identity documents such as passports, identity cards, visas, driver's licenses, bank cards, credit cards, transaction cards, access documents or cards, admission tickets, public transport tickets, diplomas or titles, preferably banknotes, identity cards, title documents, driver's licenses, and credit cards. The term "valuable goods" refers to packaging materials, especially cosmetics, dietary supplements, medicines, alcohol, tobacco products, beverages or food, electrical / electronic products, textiles, or jewelry, i.e., items that must be protected against counterfeiting and / or illegal duplication to ensure the contents of the package, such as, for example, genuine medicines. Examples of these packaging materials include, but are not limited to, labels, such as authentication brand labels, tamper-evident labels, and stickers. It is noted that the disclosed substrates, security documents, and decorative items are provided for illustrative purposes only, without limiting the scope of the present invention. Alternatively, one or more of the OELs described herein may be provided on a secondary substrate, such as a security thread, security stripe, foil, decal, window or label, and then transferred to the security document in a separate step.

[0039]

[0038] The shapes of one or more OELs described herein may be continuous or discontinuous. According to one embodiment, the shapes of one or more OELs independently represent one or more indicia, dots and / or lines. In embodiments where security documents and ornaments comprise more than one OEL, i.e., two, three, etc., the OELs may be adjacent or spaced apart.

[0040] As mentioned herein, the eye-catching OELs described herein allow a viewer to easily identify them by tilting them between about -45° and about +45°. The eye-catching visual appearance is seen as a sharp and contrasting switch-on / switch-off effect of luminance, consisting of an increase in luminance value to reach a luminance maximum value, followed by a decrease in said luminance within a viewing / observation angle of about -45° to about +45°, said change in luminance being observable with the naked eye.

[0041] 1, a person on the street typically tilts the OEL about a tilt axis τ with an observation angle between −45° and +45°, and the OEL can be tilted i) about a vertical / longitude axis (up / down movement) or ii) about a horizontal / latitude axis (left / right movement). However, any other kind of tilt axis τ can also be used.

[0042] Security Document or Decorative Item In embodiments with a single OEL, an eye-catching visual appearance can be seen when tilted i) about a vertical / longitude axis or ii) about a horizontal / latitude axis.

[0043]

[0042] In embodiments where the security document or decorative item comprises at least two OELs, ​​the eye-catching visual appearance of both of the two OELs can be seen when tilted i) about a vertical / longitude axis or ii) about a horizontal / lattitude axis, or alternatively the eye-catching visual appearance of one of the two OELs can be seen when tilted about a vertical / longitude axis, while the eye-catching visual appearance of the other of the two OELs can be seen when tilted about a horizontal / lattitude axis.

[0044]

[0043] Platelet-shaped magnetic or magnetizable pigment particles are provided in the radiation-curable coating composition and coating layer (x10) as described herein and in the at least partially cured coating layer (x10). As described herein, the methods described herein comprise a step c) of at least partially curing the coating layer (x10) to a second state, wherein the platelet-shaped magnetic or magnetizable pigment particles are fixed in their current position and orientation and can no longer move or rotate within said layer. As used herein, "at least partially curing the coating layer (x10)" means that the platelet-shaped magnetic or magnetizable pigment particles are fixed / frozen in their adopted position and orientation and can no longer move or rotate (also referred to in the art as "fixing" the particles).

[0045] As described herein, one or more optical effect layers (OELs) described herein comprise magnetically oriented platelet-shaped magnetic or magnetizable pigment particles in an at least partially cured coating layer. Preferably, the platelet-shaped magnetic or magnetizable pigment particles described herein are present in an amount of from about 5% to about 40% by weight, more preferably from about 10% to about 30% by weight, where the weight percent is based on the total weight of the at least partially cured coating layer. Preferably, the platelet-shaped magnetic or magnetizable pigment particles described herein are present in an amount of from about 5% to about 40% by weight, more preferably from about 10% to about 30% by weight, where the weight percent is based on the total weight of the radiation-curable coating layer described herein.

[0046] Due to their non-spherical shape, the platelet-shaped magnetic or magnetizable pigment particles described herein are defined as having non-isotropic reflectivity for incident electromagnetic radiation to which the cured binder material is at least partially transparent. As used herein, the term "non-isotropic reflectivity" means that the proportion of incident radiation from a first angle that is reflected by a particle in a particular (viewing / observing) direction (second angle) is a function of the particle's orientation, i.e., a change in the particle's orientation relative to the first angle can result in a different magnitude of reflection in the viewing / observing direction. Preferably, the platelet-shaped magnetic or magnetizable pigment particles described herein have non-isotropic reflectivity for incident electromagnetic radiation in some or all wavelength ranges from about 200 to about 2500 nm, more preferably from about 400 to about 700 nm, such that a change in particle orientation changes the particle's reflection in a particular direction. As known to those skilled in the art, the magnetic or magnetizable pigment particles described herein differ from conventional pigments in that conventional pigment particles exhibit the same color and reflectance regardless of particle orientation, whereas the magnetic or magnetizable pigment particles described herein exhibit reflectance or color, or both, that depend on particle orientation. In contrast to needle-shaped pigment particles, which can be considered one-dimensional particles, platelet-shaped pigment particles have X and Y axes that define the particle's major planes of extension ( FIG. 2A ). In other words, as shown in FIG. 2A , platelet-shaped pigment particles can be considered two-dimensional particles due to their large aspect ratios, with dimensions X and Y being substantially greater than dimension Z. Platelet-shaped pigment particles are also referred to in the art as oblate 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 major axis Y, also perpendicular to X, within the pigment particle.

[0047] The orientation of the platelet-shaped magnetic or magnetizable pigment particles is defined by a platelet vector, which is a vector parallel to the particle's major axis X, and the platelet vectors of adjacent platelet-shaped magnetic or magnetizable pigment particles are substantially parallel to each other (see FIG. 2B), and the platelet vectors of the platelet-shaped magnetic or magnetizable pigment particles are angled at the particle's location relative to the two-dimensional surface of the substrate (x20) by an elevation angle γ, as described herein. The elevation angle γ, as described herein, is greater than 0° and less than 30° (0°<γ<30°) or greater than 150° and less than 180° (150°<γ<180°), preferably, or greater than about 5° and less than 30° (5°≦γ<30°) or greater than 150° and less than about 175° (150°<γ≦175°). More preferably, the elevation angle γ is in the range of about 5° to about 25° (5°≦γ≦25°) or about 155° to about 175° (155°≦γ≦175°).

[0048]

[0047] OELs containing platelet-shaped magnetic or magnetizable pigment particles with an elevation angle of 0° are indistinguishable and can generally be mimicked with a non-magnetic pigment dispersed in a solvent-based ink, with the pigment being forced to assume an elevation angle of 0° when the solvent evaporates.

[0049] 3A, the platelet-shaped magnetic or magnetizable pigment particles are oriented as described above at an elevation angle α as defined herein. In other words, the elevation angle is formed by the major axis X of the platelet-shaped magnetic or magnetizable pigment particles and the two-dimensional surface of the substrate (x20), where said elevation angle γ, when measured at a cross-section of the optical effect layer (OEL) (for example, using a conoscopic scatterometer or microscope as described below) and measured counterclockwise, is greater than 0° and less than 30° (0°<γ<30°), or greater than 150° and less than 180° (150°<γ<180°), preferably greater than about 5° and less than 30° (5°≦γ<30°), or greater than 150° and less than about 175° (150°<γ≦175°). More preferably, the elevation angle γ is in the range of about 5° to about 25° (5°≦γ≦25°) or about 155° to about 175° (155°≦γ≦175°).

[0050]

[0049] In embodiments in which the platelet-shaped magnetic or magnetizable pigment particles are uniaxially oriented, for example as shown in Figure 2B, the orientation of the platelet-shaped pigment particles is defined by a platelet vector, which is a vector parallel to the particle's major axis X, and the platelet vectors of adjacent platelet-shaped magnetic or magnetizable pigment particles are substantially parallel to each other, i.e. only the major axes X of adjacent platelet-shaped magnetic or magnetizable pigment particles are substantially parallel to each other (in other words, adjacent platelet-shaped magnetic or magnetizable pigment particles have substantially the same elevation angle γ).

[0051]

[0050] In embodiments in which the platelet-shaped magnetic or magnetizable pigment particles are biaxially oriented, for example as shown in Figure 2C, the orientation of the platelet-shaped pigment particles is defined by a platelet vector, which is a vector parallel to the primary axis X of the particle, where the platelet vectors of adjacent platelet-shaped magnetic or magnetizable pigment particles are substantially parallel to each other, and is further defined by a second platelet vector, which is a vector parallel to the second axis Y of the particle, where the platelet vectors of adjacent platelet-shaped magnetic or magnetizable pigment particles are substantially parallel to each other and where the second platelet vectors of said adjacent platelet-shaped magnetic or magnetizable pigment particles are substantially parallel to each other. In embodiments in which the platelet-shaped magnetic or magnetizable pigment particles are biaxially oriented, for example as shown in Figure 2C, the platelet vectors of adjacent platelet-shaped magnetic or magnetizable pigment particles are substantially parallel to each other, so that not only are the major axes X of adjacent platelet-shaped magnetic or magnetizable pigment particles substantially parallel to each other (in other words, adjacent platelet-shaped magnetic or magnetizable pigment particles have substantially the same elevation angle γ), but the major axes Y of adjacent platelet-shaped magnetic or magnetizable pigment particles are also substantially parallel to each other. In embodiments in which the platelet-shaped magnetic or magnetizable pigment particles are biaxially oriented, for example as shown in Figure 2C, the platelet-shaped magnetic or magnetizable particles are substantially parallel to each other.

[0052]

[0051] Suitable examples of platelet-shaped magnetic or magnetizable pigment particles described herein include, but are not limited to, pigment particles comprising a magnetic metal 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 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 can be pure oxides or mixed oxides. Examples of magnetic oxides include hematite (Fe2O3), magnetite (Fe3O4), chromium dioxide (CrO2), magnetic ferrite (MFe2O4), magnetic spinel (MR2O4), magnetic hexaferrite (MFe 12 O 19 ), magnetic orthoferrite (RFeO3), and magnetic garnet M3R2(AO4)3, where M represents a divalent metal, R represents a trivalent metal, and A represents a tetravalent metal.

[0053]

[0052] Examples of platelet-shaped magnetic or magnetizable pigment particles described herein include, but are not limited to, pigment particles comprising a magnetic layer M formed from one or more of magnetic metals such as cobalt (Co), iron (Fe), or nickel (Ni); and magnetic alloys of iron, cobalt, or nickel, wherein the magnetic or magnetizable pigment particles may also be multilayer structures comprising one or more further layers. Preferably, the one or more further layers are a layer A independently formed from one or more selected from the group consisting of magnesium fluoride (MgF), silicon oxide (SiO), silicon dioxide (SiO), titanium oxide (TiO), and metal fluorides such as aluminum oxide (AlO), more preferably silicon dioxide (SiO); or a layer B independently formed from one or more 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), chromium (Cr), nickel (Ni), and even more preferably aluminum (Al); or a combination of one or more layers A as described above with one or more layers B as described above. Typical examples of platelet-shaped magnetic or magnetizable pigment particles having the above multilayer structures include, but are not limited to, A / M multilayer structures, A / M / A multilayer structures, A / M / B multilayer structures, A / B / M / A multilayer structures, A / B / M / B multilayer structures, A / B / M / B / A / multilayer structures, B / M multilayer structures, B / M / B multilayer structures, B / A / M / A multilayer structures, B / A / M / B multilayer structures, B / A / M / B / A / multilayer structures, where Layer A, Magnetic Layer M and Layer B are selected from those described above.

[0054] According to one embodiment, at least some of the preferred platelet-shaped magnetic or magnetizable particles are constituted by platelet-shaped optically variable magnetic or magnetizable pigment particles. Optically variable pigments refer to pigments that exhibit a change in lightness or a combination of a change in lightness and a change in hue. According to one embodiment, at least some of the platelet-shaped magnetic or magnetizable particles are constituted by particles that exhibit a metallic color, more preferably a silver or gold color.

[0055] In addition to the obvious security provided by the color shifting properties of the optically variable magnetic or magnetizable pigment particles, which allow an ink, coating composition, or article or security document bearing a coating layer comprising the optically variable magnetic or magnetizable pigment particles described herein to be easily detected, recognized, and / or distinguished from possible counterfeits using the naked human eye, the optical properties of the optically variable magnetic or magnetizable pigment particles can also be used as a machine-readable tool for recognition of the OEL. Thus, the optical properties of the optically variable magnetic or magnetizable pigment particles can simultaneously be used as a covert or semi-covert security feature in an authentication process in which the optical (e.g., spectral) properties of the pigment particles are analyzed, thus increasing counterfeit resistance.

[0056] The use of platelet-shaped optically variable magnetic or magnetisable pigment particles in OELs enhances the importance of OELs as a security feature in security document applications, since such materials are restricted to the security document printing industry and are not commercially available.

[0057]

[0056] Preferably, the platelet-shaped magnetic or magnetizable pigment particles are selected from the group consisting of magnetic thin film interference pigment particles, magnetic cholesteric liquid crystal pigment particles, interference coated pigment particles containing magnetic material, and mixtures of two or more thereof.

[0058]

[0057] Magnetic thin film interference pigment particles are known to those skilled in the art and are disclosed, for example, in U.S. Pat. No. 4,838,648, WO 2002 / 073250, EP 0 686675, WO 2003 / 000801, U.S. Pat. No. 6,838,166, WO 2007 / 131833, EP 2 402 401, WO 2019 / 103937, WO 2020 / 006286 and documents cited therein. Preferably, the magnetic thin film interference pigment particles comprise pigment particles having a five-layer Fabry-Perot multilayer structure, pigment particles having a six-layer Fabry-Perot multilayer structure, pigment particles having a seven-layer Fabry-Perot multilayer structure, and / or pigment particles having a multilayer structure combining one or more multilayer Fabry-Perot structures.

[0059]

[0058] A preferred five-layer Fabry-Perot multilayer structure consists of an absorber / dielectric / reflector / dielectric / absorber multilayer structure, where the reflector and / or absorber are also magnetic layers, and preferably the reflector and / or absorber are magnetic layers containing nickel, iron and / or cobalt, and / or magnetic alloys containing nickel, iron and / or cobalt, and / or magnetic oxides containing nickel (Ni), iron (Fe) and / or cobalt (Co).

[0060] A preferred six-layer Fabry-Perot multilayer structure consists of an absorber / dielectric / reflector / magnetic / dielectric / absorber multilayer structure.

[0061] A preferred seven-layer Fabry-Perot multilayer structure comprises an absorber / dielectric / reflector / magnetic / reflector / dielectric / absorber multilayer structure as disclosed in US Pat. No. 4,838,648.

[0062]

[0061] Preferred pigment particles having a multilayer structure combining one or more Fabry-Perot structures are described in WO 2019 / 103937, and consist of a combination of at least two Fabry-Perot structures, each independently comprising a reflective layer, a dielectric layer and / or an absorber layer, each of the reflector and / or absorber layers independently comprising one or more magnetic materials, and / or a magnetic layer sandwiched between the two structures. WO 2020 / 006 / 286 and EP 3587500 disclose further preferred pigment particles having a multilayer structure.

[0063]

[0062] Preferably, the reflective layers described herein are independently formed from one or more 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 alloys thereof, even more preferably selected from the group consisting of aluminum (Al), chromium (Cr), nickel (Ni), and alloys thereof, and even more preferably aluminum (Al). Preferably, the dielectric layers are independently formed from one or more selected from the group consisting of magnesium fluoride (MgF), aluminum fluoride (AlF), cerium fluoride (CeF), lanthanum fluoride (LaF), sodium aluminum fluoride (e.g., NaAlF), neodymium fluoride (NdF), samarium fluoride (SmF), barium fluoride (BaF), calcium fluoride (CaF), lithium fluoride (LiF), metal oxides such as silicon oxide (SiO), silicon dioxide (SiO), titanium oxide (TiO), and aluminum oxide (AlO), more preferably magnesium fluoride (MgF) and silicon dioxide (SiO), even more preferably magnesium fluoride (MgF). Preferably, the absorber layers are independently formed from one or more 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), metal oxides thereof, metal sulfides thereof, metal carbides thereof, and metal alloys thereof; more preferably selected from the group consisting of chromium (Cr), nickel (Ni), metal oxides thereof, and metal alloys thereof; even more preferably selected from the group consisting of chromium (Cr), nickel (Ni), and metal alloys thereof.Preferably, the magnetic layer comprises nickel (Ni), iron (Fe) and / or cobalt (Co); and / or a magnetic alloy comprising nickel (Ni), iron (Fe) and / or cobalt (Co); and / or a magnetic oxide comprising nickel (Ni), iron (Fe) and / or cobalt (Co). When magnetic thin film interference pigment particles with a seven-layer Fabry-Perot structure are preferred, it is particularly preferred that the magnetic thin film interference pigment particles comprise a seven-layer Fabry-Perot absorber / dielectric / reflector / magnetic / reflector / dielectric / absorber multilayer structure consisting of a Cr / MgF2 / Al / Ni / Al / MgF2 / Cr multilayer structure.

[0064] The magnetic thin film interference pigment particles described herein are considered safe for human health and the environment and may be multilayer pigment particles based on, for example, a five-layer Fabry-Perot multilayer, a six-layer Fabry-Perot multilayer, and a seven-layer Fabry-Perot multilayer, said pigment particles comprising one or more magnetic layers comprising a magnetic alloy having a substantially nickel-free composition comprising, by weight, about 40% to about 90% iron, about 10% to about 50% chromium, and about 0% to about 30% aluminum. Typical examples of multilayer pigment particles considered safe for human health and the environment can be found in EP 2402401, the entire contents of which are incorporated herein by reference.

[0065]

[0064] Suitable magnetic cholesteric liquid crystal pigment particles exhibiting optically variable properties include, but are not limited to, magnetic single-layer cholesteric liquid crystal pigment particles and magnetic multi-layer cholesteric liquid crystal pigment particles. Such pigment particles are disclosed, for example, in WO 2006 / 063926, U.S. Pat. No. 6,582,781, and U.S. Pat. No. 6,531,221. WO 2006 / 063926 discloses monolayers and pigment particles obtained therefrom having high gloss and color shifting properties with additional specific properties such as magnetizability. The disclosed monolayers and pigment particles are obtained by milling the monolayers and include a three-dimensionally crosslinked cholesteric liquid crystal mixture and magnetic nanoparticles. U.S. Pat. No. 6,582,781 and U.S. Pat. No. 6,410,130 disclose a method for producing a cholesteric liquid crystal pigment having a three-dimensional crosslinked cholesteric liquid crystal mixture and magnetic nanoparticles, comprising: a) a cholesteric liquid crystal having a three-dimensional crosslinked cholesteric liquid crystal mixture and a magnetic nanoparticle; b) a cholesteric liquid crystal having a three-dimensional crosslinked cholesteric liquid crystal mixture and a magnetic nanoparticle; c) a cholesteric liquid crystal having a three-dimensional crosslinked cholesteric liquid crystal mixture and a magnetic nanoparticle; d) a cholesteric liquid crystal having a three-dimensional crosslinked cholesteric liquid crystal mixture and a magnetic nanoparticle; e) a cholesteric liquid crystal having a three-dimensional crosslinked cholesteric liquid crystal mixture and a magnetic nanoparticle; g) a cholesteric liquid crystal having a three-dimensional crosslinked cholesteric liquid crystal mixture and a magnetic nanoparticle; h) a cholesteric liquid crystal having a three-dimensional crosslinked cholesteric liquid crystal mixture and a magnetic nanoparticle; h) a cholesteric liquid crystal having a three1 / B / A 2 Disclosed is a platelet-shaped cholesteric multilayer pigment particle comprising: 1 and A 2 may be the same or different and each comprise at least one cholesteric layer, and B comprises layer A 1 and A 2 US Patent No. 6,531,221 discloses platelet-shaped cholesteric multilayer pigment particles comprising an arrangement A / B and optionally C, where A and C are absorbing layers containing pigment particles imparting magnetic properties, and B is a cholesteric layer.

[0066]

[0065] Suitable interference-coated pigment particles containing one or more magnetic materials include, but are not limited to, structures consisting of a substrate selected from the group consisting of a core coated with one or more layers, where at least one of the core or one or more layers has magnetic properties. For example, suitable interference-coated pigment particles include a core made of a magnetic material such as those described above, coated with one or more layers made of one or more metal oxides, or have a structure consisting of a core formed from synthetic or natural mica, layered silicates (such as talc, kaolin, and sericite), glass (such as borosilicate), silicon dioxide (SiO2), aluminum oxide (Al2O3), titanium oxide (TiO2), graphite, and mixtures of two or more thereof. Additionally, one or more additional layers, such as color layers, may be present.

[0067]

[0066] The platelet-shaped magnetic or magnetizable pigment particles described herein preferably have a size d50 of from about 2 μm to about 50 μm (measured by direct optical granulometry).

[0068]

[0067] The platelet-shaped magnetic or magnetizable pigment particles described herein may be surface treated, typically with corrosion inhibitors and / or wetting agents, to protect the particles from deterioration that may occur in coating compositions and coating layers and / or to facilitate their incorporation into said coating compositions and coating layers.

[0069]

[0068] According to one embodiment, for example as shown in Figure 3A, the OEL described herein comprises a single at least partially cured coating layer (310) incorporating magnetically oriented platelet-shaped magnetic or magnetizable pigment particles, wherein substantially all of the platelet-shaped magnetic or magnetizable pigment particles have substantially the same elevation angle γ.

[0070] According to one embodiment, for example as shown in FIGS. 3B-3E , an OEL described herein comprises two zones containing platelet-shaped magnetic or magnetizable pigment particles, wherein substantially all of the platelet-shaped magnetic or magnetizable pigment particles in one zone have substantially the same elevation angle γ, and substantially all of the platelet-shaped magnetic or magnetizable pigment particles in the other zone have substantially the same further elevation angle γ′, wherein the elevation angle γ is greater than 0° and less than 30° (0°<γ<30°) or greater than 150° and less than 180° (150°<γ<180°), preferably greater than about 5° and less than 30° (5°≦γ<30°) or greater than 150° and less than about 175° (150°<γ≦175°). , more preferably in the range of about 5° to about 25° (5°≦γ≦25°) or about 155° to about 175° (155°≦γ≦175°), and the further elevation angle γ' is greater than 0° and less than 30° (0°<γ'<30°) or greater than 150° and less than 180° (150°<γ'<180°), preferably greater than 5° and less than 30° (5°≦γ'<30°) or greater than 150° and less than or equal to about 175° (150°<γ'≦175°), more preferably in the range of about 5° to about 25° (5°≦γ'≦25°) or about 155° to about 175° (155°≦γ'≦175°), and said elevation angle γ and the further elevation angle γ' are different from each other (preferably they differ by at least 10°) and / or are not coplanar.

[0071] According to an embodiment of the OEL comprising platelet-shaped magnetic or magnetizable pigment particles with different elevation angles γ and further elevation angles γ′, the further elevation angle γ′ has the following value: γ′=180°−γ, for example: γ is At 20°, γ' becomes 160° (ie, the magnetic orientation patterns of the two zones are substantially symmetrical).

[0072]

[0071] According to one embodiment, for example as shown in Figure 3B, an OEL described herein comprises a single at least partially cured coating layer (310) comprising platelet-shaped magnetic or magnetizable pigment particles in one or more first zones (310-a) and platelet-shaped magnetic or magnetizable pigment particles in one or more second zones (310-b), wherein substantially all of the platelet-shaped magnetic or magnetizable pigment particles in the one or more first zones (310-a) have substantially the same elevation angle γ and substantially all of the platelet-shaped magnetic or magnetizable pigment particles in the one or more second zones (310-b) have substantially the same further elevation angle γ', wherein the elevation angle γ is greater than 0° and less than 30° (0°<γ<30°) or greater than 150° and less than 180° (150°<γ<18 0°), preferably between about 5° and less than 30° (5°≦γ<30°) or between about 150° and about 175° (150°<γ≦175°), more preferably between about 5° and about 25° (5°≦γ≦25°) or between about 155° and about 175° (155°≦γ≦175°), and the further elevation angle γ' is between about 0° and less than 30° (0°<γ'<30°) or between about 150° and less than 180° (150°<γ γ'<180°), preferably in the range of about 5° to less than 30° (5°≦γ'<30°) or greater than 150° to about 175° (150°<γ'≦175°), more preferably between about 5° and about 25° (5°≦γ'≦25°) or between about 155° and about 175° (155°≦γ'≦175°), wherein said elevation angle γ and the further elevation angle γ' differ from each other (preferably they differ by at least 10°) and / or are not coplanar.

[0073]

[0072] According to one embodiment, for example as shown in Figures 3C-3E, an OEL described herein comprises an at least partially cured coating layer (310) incorporating magnetically oriented platelet-shaped magnetic or magnetizable pigment particles, wherein substantially all of the platelet-shaped magnetic or magnetizable pigment particles have substantially the same elevation angle γ, and further comprises an at least partially cured second coating layer (311) incorporating magnetically oriented second platelet-shaped magnetic or magnetizable pigment particles, wherein the platelet vectors of the second platelet-shaped magnetic or magnetizable pigment particles are angled by a further elevation angle γ' with respect to the two-dimensional surface of the substrate (x20) at the particle's location, the further elevation angle γ' being greater than 0° and less than 30° (0°<γ'<30°) or greater than 150° and less than 180° (150°<γ'<180°), and wherein said elevation angle γ and further elevation angle γ' are different from each other. The at least partially cured second coating layer (x11) at least partially or completely overlaps the at least partially cured coating layer (x10), or the at least partially cured second coating layer (x11) is adjacent to the at least partially cured coating layer (x10), or the at least partially cured second coating layer (x11) is spaced apart from the at least partially cured coating layer (x10).

[0074] According to one embodiment, for example as shown in Figure 3C, an OEL as described herein comprises two at least partially cured coating layers (310 and 311). The OEL comprises: i) an at least partially cured coating layer (310) incorporating magnetically oriented platelet-shaped magnetic or magnetizable pigment particles as described herein; and ii) an at least partially cured second coating layer (311) incorporating magnetically oriented second platelet-shaped magnetic or magnetizable pigment particles, said at least partially cured second coating layer (311) partially overlapping the at least partially cured coating layer (310), wherein substantially all of the platelet-shaped magnetic or magnetizable pigment particles in the at least partially cured coating layer (310) have substantially the same further elevation angle γ and substantially all of the second platelet-shaped magnetic or magnetizable pigment particles in the at least partially cured second coating layer (311) have substantially the same further elevation angle γ', wherein the elevation angle γ is greater than 0° and less than 30° (0 and the further elevation angle γ' is within the range of greater than 0° and less than 30° (0°<γ'<30°) or greater than 150° and less than 180° (150°<γ<180°), preferably greater than about 5° and less than 30° (5°≦γ<30°) or greater than 150° and less than about 175° (150°<γ≦175°), more preferably between about 5° and about 25° (5°≦γ≦25°) or between about 155° and about 175° (155°≦γ≦175°), and the further elevation angle γ' is within the range of greater than 0° and less than 30° (0°<γ'<30°) or greater than 150° and less than 175° (150°<γ≦175°). is greater than 180° (150°<γ'<180°), preferably between about 5° and less than 30° (5°≦γ'<30°) or greater than 150° and less than about 175° (150°<γ'≦175°), more preferably between about 5° and about 25° (5°≦γ'≦25°) or between about 155° and about 175° (155°≦γ'≦175°), wherein the elevation angle γ and the further elevation angle γ' are different from each other (preferably they differ by at least 10°) and / or are not coplanar.

[0075]

[0074] According to one embodiment, for example as shown in Figure 3D, the OEL described herein comprises two at least partially cured coating layers (310 and 311). The OEL comprises: i) an at least partially cured coating layer (310) incorporating magnetically oriented platelet-shaped magnetic or magnetizable pigment particles as described herein; and ii) an at least partially cured second coating layer (311) incorporating magnetically oriented second platelet-shaped magnetic or magnetizable pigment particles, said at least partially cured second coating layer (311) completely overlapping the at least partially cured coating layer (310), wherein substantially all of the platelet-shaped magnetic or magnetizable pigment particles in the at least partially cured coating layer (310) have substantially the same elevation angle γ, and substantially all of the second platelet-shaped magnetic or magnetizable pigment particles in the at least partially cured second coating layer (311) have substantially the same elevation angle γ', wherein the elevation angle γ is greater than 0° and less than 30° (0°<γ <30°) or greater than 150° and less than 180° (150°<γ<180°), preferably greater than about 5° and less than 30° (5°≦γ<30°) or greater than 150° and less than about 175° (150°<γ≦175°), more preferably between about 5° and about 25° (5°≦γ≦25°) or between about 155° and about 175° (155°≦γ≦175°), and the further elevation angle γ' is greater than 0° and less than 30° (0°<γ'<30°) or greater than 150°. The elevation angle γ and the further elevation angle γ' are preferably within the range of about 5° to about 25° (5°≦γ'≦25°) or about 155° to about 175° (155°≦γ'≦175°), and more preferably within the range of about 5° to about 25° (5°≦γ'≦25°) or about 155° to about 175° (155°≦γ'≦175°), wherein the elevation angle γ and the further elevation angle γ' are different from each other (preferably, they differ by at least 10°) and / or are not coplanar.

[0076] According to one embodiment, for example as shown in FIG. 3E, the OEL described herein comprises two at least partially cured coating layers (310 and 311). The OEL comprises i) an at least partially cured coating layer (310) incorporating magnetically oriented platelet-shaped magnetic or magnetizable pigment particles as described herein, and ii) an at least partially cured second coating layer (311) incorporating magnetically oriented second platelet-shaped magnetic or magnetizable pigment particles, said at least partially cured second coating layer being adjacent to (FIG. 3E) or spaced apart (not shown) from (the at least partially cured coating layer (310), wherein substantially all of the platelet-shaped magnetic or magnetizable pigment particles in the at least partially cured coating layer (310) have substantially the same further elevation angle γ, and substantially all of the second platelet-shaped magnetic or magnetizable pigment particles in the at least partially cured second coating layer (311) have substantially the same further elevation angle γ', wherein the elevation angle γ is between 0° and the elevation angle γ' is in the range of greater than 0° and less than 30° (0°<γ<30°) or greater than 150° and less than 180° (150°<γ<180°), preferably greater than about 5° and less than 30° (5°≦γ<30°) or greater than 150° and less than about 175° (150°<γ≦175°), more preferably between about 5° and about 25° (5°≦γ≦25°) or between about 155° and about 175° (155°≦γ≦175°), and the elevation angle γ' is greater than 0° and less than 30° (0°<γ'<30°) or is greater than 150° and less than 180° (150°<γ'<180°), preferably greater than about 5° and less than 30° (5°≦γ'<30°) or greater than 150° and less than about 175° (150°<γ'≦175°), more preferably in the range of about 5° to about 25° (5°≦γ'≦25°) or about 155° to about 175° (155°≦γ'≦175°), wherein said elevation angle γ and the further elevation angle γ' differ from each other (preferably they differ by at least 10°) and / or are not coplanar.

[0077]

[0076] The substrate (x20) described herein is preferably selected from the group consisting of paper or other fibrous materials (including woven and nonwoven fibrous materials), such as cellulose, paper-containing materials, glass, metal, ceramic, plastics and polymers, metallized plastics or polymers, composite materials, and mixtures or combinations of two or more thereof. Typical paper, paper-like, or other fibrous materials are formed from a variety of fibers, including, but not limited to, abaca, cotton, flax, wood pulp, and blends thereof. As is well known to those skilled in the art, cotton and cotton / linen blends are preferred for banknotes, while wood pulp is commonly used for security documents other than banknotes. According to another embodiment, the substrate (x20) described herein is based on plastics and polymers, metallized plastics or polymers, composite materials, and mixtures or combinations of two or more thereof. Suitable examples of plastics and polymers include polyolefins such as polypropylene (PP), including polyethylene (PE) and biaxially oriented polypropylene (BOPP), polyamides, polyesters such as poly(ethylene terephthalate) (PET), poly(1,4-butylene terephthalate) (PBT), poly(ethylene 2,6-naphthoate) (PEN), and polyvinyl chloride (PVC). Spunbond olefin fibers, such as those sold under the Tyvek® trademark, can also be used as substrates. Typical examples of metallized plastics or polymers include the above-mentioned plastic or polymer materials having a metal disposed on the surface in a continuous or discontinuous manner. Typical examples of metals include, but are not limited to, aluminum (Al), chromium (Cr), copper (Cu), gold (Au), silver (Ag), alloys thereof, and combinations of two or more of the above-mentioned metals. Metallization of the above-mentioned plastic or polymer materials can be performed by electrodeposition, high-vacuum coating, or sputtering processes. Typical examples of composite materials include, but are not limited to, multi-layer structures or laminates of paper and at least one plastic or polymer material such as those mentioned above, as well as plastic and / or polymer fibers incorporated into paper-like or fibrous materials such as those mentioned above.Of course, the substrate may contain further additives known to those skilled in the art, such as fillers, sizing agents, brighteners, processing aids, strength agents, or wet strength agents. When the OELs described herein are used for decorative or cosmetic purposes, including, for example, fingernail lacquers, the OELs may be produced on other types of substrates, including fingernails, artificial nails, or other parts of animals or humans. The substrates (x20) described herein may be in the form of a web, sheet, thread reel, film reel, roll label, or label stock.

[0078]

[0077] When one or more OELs described herein are on a security document, the substrate may comprise printed, coated, or laser-marked or laser-perforated indicia, watermarks, security threads, fibers, planchets, luminescent compounds, windows, foils, decals, and combinations of two or more thereof, for the purpose of further increasing the level of security and the resistance of said security document to counterfeiting and illegal duplication. For the same purpose of further increasing the level of security and the resistance of said security document to counterfeiting and illegal duplication, the substrate may comprise one or more marker substances or taggants and / or machine-readable substances (e.g., luminescent substances, UV / visible / IR absorbing substances, magnetic substances, and combinations thereof).

[0079] According to one embodiment, security documents and decorative articles comprising a substrate (x20) and one or more OELs as described herein further comprise one or more patterns, each of which independently has the shape of an indicia, and wherein said one or more patterns are present between the substrate (x20) and the one or more OELs (in other words, one or more OELs at least partially overlap one or more patterns). As used herein, the terms "indicia" and "indicia" shall mean continuous and discontinuous layers of identifying marks or signs or patterns. Preferably, the indicia as 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 encoded marks such as encoded alphanumeric data, one-dimensional barcodes, two-dimensional barcodes, QR codes, data matrices, and IR-readable codes. One or more of the indicia described herein may be solid indicia and / or raster indicia.

[0080] According to one embodiment, the security documents and decorative articles comprising a substrate (x20) and one or more OELs as described herein further comprise one or more primer layers, said one or more primer layers being between the substrate (x20) and the one or more OELs, ​​which may improve the quality or promote adhesion of the one or more OELs as described herein. Examples of such primer layers can be found in WO 2010 / 058026.

[0081]

[0080] To improve the durability in terms of stain or chemical resistance and cleanability, and thus the shelf life of security documents or decorative articles comprising one or more OELs described herein, or to modify their aesthetic appearance (e.g., optical gloss), one or more protective layers can be applied onto one or more OELs. If present, the one or more protective layers are generally formed from a protective varnish. The protective varnish may be a radiation-curable composition, a heat-drying composition, or any combination thereof. Preferably, the one or more protective layers are radiation-curable compositions, more preferably UV-Vis-curable compositions. The protective layer(s) are generally applied after the formation of the OEL.

[0082] The OELs described herein can be applied directly onto a substrate (x20) and remain permanently on the substrate (such as for banknote or label applications). Alternatively, the OELs may be applied onto a temporary substrate for manufacturing purposes, after which the OEL is removed therefrom.

[0083] Alternatively, one or more adhesive layers may be present on one or more OELs or on the substrate (x20), said one or more adhesive layers being on the side of the substrate opposite to the side on which one or more OELs are provided, and / or on the same side as one or more OELs and on one or more OELs. Thus, one or more adhesive layers can be applied to one or more OELs or to the substrate, said one or more adhesive layers being applied after the curing step is complete. Such objects can be attached to any kind of document or other article or item without involving printing or other processes requiring machines and considerable labor. Alternatively, the substrates described herein, which comprise one or more OELs described herein, may be in the form of a transfer foil that can be applied to a document or article in a separate transfer step. For this purpose, the substrate is provided with a release coating, on which one or more OELs are formed.

[0084]

[0083] The present invention provides a method for producing one or more optical effect layers (OELs) as described herein on a substrate (x20) having a two-dimensional surface as described herein.

[0085] The method described herein comprises the step a) of applying onto the surface of a substrate (x20) as described herein a radiation curable coating composition comprising platelet-shaped magnetic or magnetizable pigment particles as described herein, said radiation curable coating composition being in a first liquid state that allows its application as a coating layer (x10) and that is still at least partially uncured (i.e., wet) to allow the pigment particles to move and rotate within the layer. As the radiation curable coating composition described herein is adapted to be applied onto the surface of a substrate (x20), the radiation curable coating composition comprises at least a binder material and magnetic or magnetizable pigment particles, said composition being in a form that allows its processing in the desired printing or coating equipment. Preferably, said step a) is carried out by a printing process preferably selected from the group consisting of screen printing, rotogravure printing, flexography, intaglio printing (also known in the art as engraved copperplate printing or engraved steel die printing), pad printing, and curtain coating, more preferably selected from the group consisting of screen printing, gravure printing, pad printing, and flexography, even more preferably selected from the group consisting of screen printing, gravure printing, and flexography.

[0086]

[0085] The method described herein further comprises step b) of exposing the coating layer (x10) to a magnetic field of a magnetic field generator (x30) so as to orient at least a portion of the platelet-shaped magnetic or magnetizable pigment particles, wherein the platelet vectors of the platelet-shaped magnetic or magnetizable pigment particles are angled by an elevation angle γ with respect to the two-dimensional surface of the substrate (x20) at the position of the particles, said elevation angle γ being greater than 0° and less than 30° (0°<γ<30°) or greater than 150° and less than 180° (150°<γ<180°), preferably between about 5° and less than 30° (5°≦γ<30°) or greater than 150° and less than about 175° (150°<γ≦175°), more preferably between about 5° and about 25° (5°≦γ≦25°) or between about 155° and about 175° (155°≦γ≦175°).

[0087]

[0086] The orientation of the platelet-shaped magnetic or magnetizable pigment particles and the elevation angle γ described herein are obtained by subjecting the platelet-shaped magnetic or magnetizable pigment particles to the magnetic field of a magnetic field generating device (x30) described herein in one or more regions (illustrated as dotted rectangles A and A') in which the magnetic field is substantially uniform (i.e., a magnetic field having a substantially constant magnitude and direction throughout the region of interest (in the case of uniaxial orientation) or a magnetic field substantially confined to a plane (in the case of biaxial orientation)), and a substrate (x20) supporting a coating layer (x10) is provided in said one or more regions with an angle α between the coating layer (x10) and the tangent to the magnetic field lines of the magnetic field of the magnetic field generating device (x30) in the one or more regions in which the magnetic field is substantially uniform. The angle α is greater than 0° and less than 30° (0°<α<30°), or greater than 150° and less than 180° (150°<α<180°), preferably greater than about 5° and less than 30° (5°≦α<30°), or greater than 150° and less than about 175° (150°<α≦175°), and more preferably within the range of about 5° to about 25° (5°≦α≦25°) or about 155° to about 175° (155°≦α≦175°).

[0088]

[0087] Step b) described herein is carried out so as to uniaxially or biaxially orient at least a portion of the platelet-shaped magnetic or magnetizable pigment particles described herein. In contrast to uniaxial orientation, in which the magnetic or magnetizable pigment particles are oriented in such a way that only their major axes are constrained by the magnetic field (Fig. 2B), performing biaxial orientation means that the platelet-shaped magnetic or magnetizable pigment particles are oriented so that their two major axes X and Y are constrained (Fig. 2C). That is, each platelet-shaped magnetic or magnetizable pigment particle can be considered to have a major axis in the plane of the pigment particle and a minor axis perpendicular to the plane of the pigment particle. Axes of the platelet-shaped magnetic or magnetizable pigment particles X and Y are each oriented according to the magnetic field. Effectively, this results in adjacent platelet-shaped magnetic pigment particles being close together in space so that they are substantially parallel to one another. In other words, the biaxial orientation aligns the planes of the platelet-shaped magnetic or magnetizable pigment particles so that the planes of said pigment particles are oriented so that they are substantially parallel to the planes of adjacent (in all directions) platelet-shaped magnetic or magnetizable pigment particles.

[0089] According to one embodiment, step b) is carried out to uniaxially orient at least a portion of the platelet-shaped magnetic or magnetizable pigment particles described herein. Suitable magnetic field generating devices for uniaxially orienting the platelet-shaped magnetic or magnetizable pigment particles described herein are not limited.

[0090] According to one embodiment shown in Fig. 4A1, a suitable magnetic field generator (430) for uniaxially orienting at least a portion of platelet-shaped magnetic or magnetizable pigment particles consists of a bar dipole magnet. As shown in Fig. 4A1, the platelet-shaped magnetic or magnetizable pigment particles in a coating layer (410) on a substrate (420) are exposed to the magnetic field (magnetic field lines shown as lines with arrows pointing from north to south poles) of the magnetic field generator (430) described herein in one or more regions (shown as dotted rectangles A) where the magnetic field is substantially uniform, the magnetic field lines being substantially parallel to each other in said one or more regions, and the substrate (420) supporting the coating layer (410) being provided in said one or more regions with an angle α as described herein.

[0091] According to one embodiment shown in Fig. 4A2, a suitable magnetic field generator (430) for uniaxially orienting at least a portion of platelet-shaped magnetic or magnetizable pigment particles consists of an assembly comprising two bar dipole magnets (M1, M2) having the same magnetic direction and an iron yoke (Y), said magnetic field generator being described in U.S. Patent No. 7,047,883. As shown in Fig. 4A2, the platelet-shaped magnetic or magnetizable pigment particles in a coating layer (410) on a substrate (420) are exposed to a magnetic field (indicated as lines with arrows pointing from north to south poles) of a magnetic field generator (430) described herein in one or more regions (indicated as dotted rectangles A) where the magnetic field is substantially uniform, the magnetic field lines being substantially parallel to each other in said one or more regions, and the substrate (420) supporting the coating layer (410) being disposed in said one or more regions at an angle α as described herein.

[0092] 6A-6B and used in the following examples, a suitable magnetic field generator (630) for uniaxially orienting at least a portion of platelet-shaped magnetic or magnetizable pigment particles consists of a rectangular assembly of two bar dipole magnets (M1, M2) and two magnetic pole pieces (P1, P2). The platelet-shaped magnetic or magnetizable pigment particles in a coating layer (610) on a substrate (620) are exposed to the magnetic field (shown as lines with arrows pointing from north to south poles) of the magnetic field generator (630) in one or more regions (shown as dashed rectangles A) where the magnetic field is substantially uniform, the magnetic field lines being substantially parallel to each other in said regions, and the substrate (620) supporting the coating layer (610) being disposed in said one or more regions at an angle α as described herein.

[0093] According to another embodiment, step b) is performed to biaxially orient at least a portion of the platelet-shaped magnetic or magnetizable pigment particles. In embodiments where the method described herein comprises exposing the coating layer (x10) to the magnetic field of a magnetic field generator (x30) described herein to biaxially orient at least a portion of the magnetic or magnetizable pigment particles, the coating layer (x10) may be exposed to said magnetic field generator two or more times. Suitable magnetic field generators for biaxially orienting the platelet-shaped magnetic or magnetizable pigment particles described herein are not limited. As known to those skilled in the art, biaxial orientation of platelet-shaped magnetic or magnetizable pigment particles requires a dynamic magnetic field (i.e., a time-variable / time-dependent magnetic field) that forces the particles to vibrate by changing their direction until both the X- and Y-major axes are aligned. In other words, biaxial orientation requires unaccompanied movement of the coating layer (x10) comprising the platelet-shaped magnetic or magnetizable pigment particles with respect to the magnetic field generator.

[0094] According to one embodiment shown in Figure 10 of WO 2018 / 019594, a suitable magnetic field generator (430) for biaxially orienting at least a portion of platelet-shaped magnetic or magnetizable pigment particles comprises a linear arrangement of at least four magnets (M1-M4) arranged in a staggered or zigzag pattern. As shown in Figure 4B1, the platelet-shaped magnetic or magnetizable pigment particles in a coating layer (410) on a substrate (420) are exposed to the magnetic field of the magnetic field generator (430) (shown as lines with arrows pointing from north to south poles) in one or more regions (shown as dotted rectangles A, A') where the magnetic field is substantially uniform, the magnetic field lines being substantially parallel to each other in said one or more regions, and the substrate (420) supporting the coating layer (410) being disposed in said one or more regions at an angle α as described herein. EP 2 157 141 A1 discloses a similar suitable magnetic field generating device in FIG. 5, which can be used to biaxially orient at least a portion of platelet-shaped magnetic or magnetizable pigment particles, and which consists of a linear arrangement of at least three, preferably at least four, magnets arranged in a staggered or zigzag pattern.

[0095] According to one embodiment shown in Figure 4B2 and Figures 8A-8B of WO 2018 / 019594, a suitable magnetic field generator (430) for biaxially orienting at least a portion of platelet-shaped magnetic or magnetizable pigment particles consists of two dipole magnets (M1, M2) with opposite magnetic directions. As shown in Figure 4B2, the platelet-shaped magnetic or magnetizable pigment particles in a coating layer (410) on a substrate (420) are exposed to the magnetic field of the magnetic field generator (430) (shown as lines with arrows pointing from north to south poles) in one or more regions (shown as dotted rectangles A, A') where the magnetic field is substantially uniform, the magnetic field lines being substantially parallel to each other in said one or more regions, and the substrate (420) supporting the coating layer (410) being disposed in said one or more regions at an angle α as described herein.

[0096] According to one embodiment shown in Figure 4B3 and Figures 7A-7B of WO 2018 / 019594, a suitable magnetic field generator (430) for biaxially orienting at least a portion of platelet-shaped magnetic or magnetizable pigment particles consists of two dipole magnets (M1, M2) with the same magnetic direction. As shown in Figure 4B3, the platelet-shaped magnetic or magnetizable pigment particles in a coating layer (410) on a substrate (420) are exposed to the magnetic field of the magnetic field generator (430) (shown as lines with arrows pointing from north to south poles) in one or more regions (shown as dotted rectangles A) where the magnetic field is substantially uniform, the magnetic field lines being substantially parallel to each other in said one or more regions, and the substrate (420) supporting the coating layer (410) being disposed in said one or more regions at an angle α as described herein.

[0097] According to one embodiment shown in Figure 4B4 and Figures 3A-3B of WO 2018 / 019594, a suitable magnetic field generator (430) for biaxially orienting at least a portion of platelet-shaped magnetic or magnetizable pigment particles consists of a Halbach array with five dipole magnets (M1-M5). As shown in Figure 4B4, the platelet-shaped magnetic or magnetizable pigment particles in a coating layer (410) on a substrate (420) are exposed to the magnetic field of the magnetic field generator (430) (shown as lines with arrows pointing from north to south poles) in one or more regions (shown as dotted rectangles A) where the magnetic field is substantially uniform, the magnetic field lines are substantially parallel to each other in said one or more regions, and the substrate (420) supporting the coating layer (410) is disposed in said one or more regions at an angle α as described herein.

[0098] According to one embodiment shown in Figure 4B5 and Figure 12A of WO 2016 / 083259, a suitable magnetic field generator (430) for biaxially orienting at least a portion of platelet-shaped magnetic or magnetizable pigment particles comprises a Halbach cylinder assembly comprising four structures, each comprising a magnet bar (M1-M4) surrounded by a magnet wire coil (not shown). As shown in Figure 4B5, the platelet-shaped magnetic or magnetizable pigment particles in a coating layer (410) on a substrate (420) are exposed to the magnetic field (indicated as lines with arrows pointing from north to south poles) of the magnetic field generator (430) in one or more regions (indicated as dotted rectangles A) where the magnetic field is substantially uniform, the magnetic field lines being substantially parallel to each other in said one or more regions, and the substrate (420) supporting the coating layer (410) being disposed in said one or more regions at an angle α as described herein.

[0099]

[0098] According to one embodiment shown in Figure 4B6 and Figure 2A of co-pending application EP 20176506.2, a suitable magnetic field generating device (430) for biaxially orienting at least a portion of platelet-shaped magnetic or magnetizable pigment particles consists of an assembly of eight bar dipole magnets (M1 to M8), said assembly comprising a first set comprising a first bar dipole magnet (M4) and two second bar dipole magnets (M1, M6), a second set comprising a first bar dipole magnet (M5) and two second bar dipole magnets (M3; M8), and a first pair of third bar dipole magnets (M2, M7). As shown in Figure 4B6, platelet-shaped magnetic or magnetizable pigment particles in a coating layer (410) on a substrate (420) are exposed to the magnetic field of a magnetic field generator (430) (shown as lines with arrows pointing from north pole to south pole) in one or more regions (shown as dotted rectangles A) where the magnetic field is substantially uniform, the magnetic field lines are substantially parallel to each other in said one or more regions, and the substrate (420) supporting the coating layer (410) is positioned in said one or more regions at an angle α described herein.

[0100] According to one embodiment shown in FIGS. 5A1-3 and used in the following examples, a magnetic field generator (530) suitable for biaxially orienting at least a portion of the platelet-shaped magnetic or magnetizable pigment particles comprises nine bar dipole magnets (M1-M3) arranged in a row with alternating N-S magnetic directions. 9 As shown in Figure 5A2, platelet-shaped magnetic or magnetizable pigment particles in a coating layer (510) on a substrate (520) are exposed to a magnetic field (shown as lines with arrows pointing from north to south poles) of a magnetic field generator (530) in one or more regions (shown as dotted rectangles A) where the magnetic field is substantially uniform, the magnetic field lines being substantially parallel to each other in said one or more regions, and the substrate (520) supporting the coating layer (510) is disposed in said one or more regions at an angle α as described herein.

[0101]

[0100] As known to those skilled in the art, when the substrate (x20) supporting the coating layer (x10) is static or moves in association with the magnetic field generating device shown in Figures 4B1 to 4B6 and 5 (i.e. moves at the same speed as the magnetic field generating device), the platelet-shaped magnetic or magnetizable pigment particles become uniaxially oriented when exposed to the device.

[0102]

[0101] During the magnetic orientation of magnetic or magnetizable pigment particles described herein, the substrate (x20) supporting the coating layer (x10) may be placed on a non-magnetic support plate (x40) formed from one or more non-magnetic materials.

[0103]

[0102] The method described herein further comprises, partially simultaneously with or subsequent to step b), step c) of at least partially curing the coating layer (x10) in a curing unit (x40) as described herein, so as to at least partially fix the position and orientation of the platelet-shaped magnetic or magnetizable pigment particles in the coating layer (x10) and produce an at least partially cured coating layer (x10) as described herein, wherein the elevation angle γ as described herein is greater than 0° and less than 30° (0°<γ<30°) or greater than 150° and less than 180° (150°<γ<180°), preferably greater than about 5° and less than 30° (5°≦γ<30°) or greater than 150° and less than about 175° (150°<γ≦175°), more preferably in the range of from about 5° to about 25° (5°≦γ≦25°) or from about 155° to about 175° (155°≦γ≦175°).

[0104]

[0103] For embodiments in which step b) is carried out so as to biaxially orient at least a portion of the platelet-shaped magnetic or magnetisable pigment particles described herein, step c) of at least partially curing the coating layer (x10) in a curing unit (x40) described herein is preferably carried out partially simultaneously with step b).

[0105]

[0104] In one embodiment for preparing one or more OELs such as the embodiment shown in Figure 3B and described above, i.e., said OEL comprises or consists of a single at least partially cured coating layer (x10) comprising platelet-shaped magnetic or magnetizable pigment particles in one or more first zones (x10-a) and platelet-shaped magnetic or magnetizable pigment particles in one or more second zones (x10-b), wherein the magnetically oriented platelet-shaped magnetic or magnetizable pigment particles have an elevation angle γ in the one or more first zones (x10-a) and are aligned in one or more second zones (x10-b). a second zone (x10-b) of the number of elevation angles γ and γ′ are incorporated with a further elevation angle γ′, wherein the elevation angle γ and the further elevation angle γ′ are independently greater than 0° and less than 30° (0°<γ,γ′<30°) or greater than 150° and less than 180° (150°<γ,γ′<180°), preferably greater than 5° and less than 30° (5°≦γ,γ′<30°) or greater than 150° and less than 175° (150°<γ,γ′≦175°), more preferably between about 5° and about 25° (5°≦γ,γ′≦25°) or between about 155° and about 175° (155°≦γ,γ′≦175°), and wherein the elevation angles γ and γ′ are different from each other and / or are not coplanar, according to an embodiment the method comprises: a) applying onto the surface of a substrate (x20) as described herein a radiation-curable coating composition comprising platelet-shaped magnetic or magnetizable pigment particles as described herein; b) exposing the coating layer (x10) to a magnetic field of a magnetic field generator (x30) as described herein, with a substrate (x20) supporting the coating layer (x10) in one or more regions where the magnetic field as described herein is substantially uniform at an angle α as described herein; c) selectively at least partially hardening one or more first regions of the coating layer (x10) using a selective hardening unit (x50) to fix at least a portion of the platelet-shaped magnetic or magnetizable particles in their adopted positions and orientations, while one or more second zones of the coating layer (x10) remain unexposed to irradiation, said step being carried out partially simultaneously with or subsequent to step b); d) exposing the coating layer (x10) to a second magnetic field of a second magnetic field generator in one or more regions where the second magnetic field is uniform, so as to orient at least a portion of the platelet-shaped magnetic or magnetizable pigment particles, wherein a substrate (x20) supporting the coating layer (x10) is provided in one or more regions where the magnetic field is substantially uniform, and the coating layer (x10) and the tangent of the magnetic field lines of the second magnetic field in one or more regions where the magnetic field is substantially uniform are aligned. and the angle α' between the two is greater than 0° and less than 30° (0°<α'<30°) or greater than 150° and less than 180° (150°<α'<180°), preferably greater than about 5° and less than 30° (5°≦α'<30°) or greater than 150° and less than about 175° (150°<α'≦175°), more preferably within the range of about 5° to about 25° (5°≦α'≦25°) or about 155° to about 175° (155°≦α'≦175°), and α' is different from α; e) partially simultaneously with or subsequent to step d) of exposing the coating layer (x10) to the magnetic field of the second magnetic field generator, step e) of at least partially curing the coating layer (x10) in a curing unit (x40) as described herein; Includes.

[0106]

[0105] In one embodiment for preparing one or more OELs such as those shown in Figures 3C-3D and described above, i.e., the OEL comprises or consists of i) an at least partially cured coating layer (x10) incorporating magnetically oriented platelet-shaped magnetic or magnetizable pigment particles, and ii) an at least partially cured second coating layer (x11) incorporating magnetically oriented second platelet-shaped magnetic or magnetizable pigment particles, wherein the at least partially cured second coating layer (x11) partially or fully overlaps the at least partially cured coating layer (x10), wherein substantially all of the platelet-shaped magnetic or magnetizable pigment particles in the at least partially cured coating layer (x10) have substantially the same elevation angle γ, and wherein substantially all of the second platelet-shaped magnetic or magnetizable pigment particles in the at least partially cured second coating layer (x11) have substantially the same elevation angle γ. wherein the magnetizable pigment particles have substantially the same further elevation angle γ', and the orientation of each of the second platelet-shaped pigment particles is defined by a platelet vector as described herein, and the platelet vector of the second platelet-shaped magnetic or magnetizable pigment particle is angled by the further elevation angle γ' with respect to the two-dimensional surface of the substrate (x20) at the location of the particle, and the elevation angle γ and the further elevation angle γ' are independently greater than 0° and less than 30° (0°<γ, γ'<30°) or 15°. According to one embodiment, the elevation angle γ and the further elevation angle γ' are in the range of greater than 0° and less than 180° (150°<γ,γ'<180°), preferably greater than about 5° and less than 30° (5°≦γ,γ'<30°) or greater than 150° and less than about 175° (150°<γ,γ'≦175°), more preferably between about 5° and about 25° (5°≦γ,γ'≦25°) or between about 155° and about 175° (155°≦γ,γ'≦175°), wherein the elevation angle γ and the further elevation angle γ' are different from each other and / or are not coplanar, a) applying onto the surface of a substrate (x20) as described herein a radiation-curable coating composition comprising platelet-shaped magnetic or magnetizable pigment particles as described herein; b) exposing the coating layer (x10) to a magnetic field of a magnetic field generator (x30) as described herein, with a substrate (x20) supporting the coating layer (x10) in one or more regions where the magnetic field as described herein is substantially uniform at an angle α as described herein; partially simultaneously with or subsequent to step b), step c) of at least partially curing the coating layer (x10) in a curing unit (x40) as described herein; Step c) is followed by a step d) of applying, either partially (FIG. 3C) or completely (FIG. 3D) onto the at least partially cured coating layer (x10), a second radiation-curable coating composition comprising second platelet-shaped magnetic or magnetizable pigment particles, said second radiation-curable coating composition being in a first liquid state to form a second coating layer (x11), said second radiation-curable coating composition being the same as or different from the radiation-curable coating composition of step a); a step e) of exposing the second coating layer (x11) to a second magnetic field of a second magnetic field generator in one or more regions where the second magnetic field is uniform, so as to orient at least a portion of the second platelet-shaped magnetic or magnetizable pigment particles, wherein a substrate (x20) supporting the second coating layer (x11) is provided in said one or more regions, and the angle α' between the second coating layer (x11) and a tangent to the magnetic field lines of the second magnetic field in one or more regions where the magnetic field is substantially uniform is greater than 0°; step e) in which the second magnetic field generator is the same as or different from the magnetic field generator of step b), and α' is different from α, and partially simultaneously with or subsequent to step e) of exposing the second coating layer (x11) to a second magnetic field generating device, step f) of at least partially curing the second coating layer (x11) in a curing unit (x40) so as to at least partially fix the position and orientation of the second platelet-shaped magnetic or magnetizable pigment particles in the second coating layer (x11) and to produce an at least partially cured second coating layer (x11); Includes.

[0107]

[0106] In one embodiment for preparing one or more OELs such as the embodiment shown in Figure 3E and described above, i.e., the OEL comprises or consists of i) an at least partially cured coating layer (x10) incorporating magnetically oriented platelet-shaped magnetic or magnetizable pigment particles, and ii) an at least partially cured second coating layer (x11) incorporating second platelet-shaped magnetic or magnetizable pigment particles, wherein the at least partially cured second coating layer (x11) is adjacent to (Figure 3E) or spaced apart from (not shown) the at least partially cured coating layer (x10), wherein substantially all of the platelet-shaped magnetic or magnetizable pigment particles in the at least partially cured coating layer (x10) have substantially the same elevation angle γ, and wherein substantially all of the second platelet-shaped magnetic or magnetizable pigment particles in the at least partially cured second coating layer (x11) have substantially the same elevation angle γ. and two platelet-shaped magnetic or magnetizable pigment particles having substantially the same further elevation angle γ', wherein the orientation of each of the second platelet-shaped pigment particles is defined by a platelet vector as described herein, wherein the platelet vector of the second platelet-shaped magnetic or magnetizable pigment particle is angled by the further elevation angle γ' relative to the two-dimensional surface of the substrate (x20) at the particle's location, and wherein the elevation angle γ and the further elevation angle γ' are independently greater than 0° and less than 30° (0°<γ, γ'<3 0°) or greater than 150° and less than 180° (150°<γ,γ'<180°), preferably greater than about 5° and less than 30° (5°≦γ,γ'<30°) or greater than 150° and less than about 175° (150°<γ,γ'≦175°), more preferably in the range of about 5° to about 25° (5°≦γ,γ'≦25°) or about 155° to about 175° (155°≦γ,γ'≦175°), wherein said elevation angle γ and the further elevation angle γ' are different from each other and / or are not coplanar, according to one embodiment the method comprises: a) applying onto the surface of a substrate (x20) as described herein a radiation-curable coating composition comprising platelet-shaped magnetic or magnetizable pigment particles as described herein; b) exposing the coating layer (x10) to a magnetic field of a magnetic field generator (x30) as described herein, with a substrate (x20) supporting the coating layer (x10) in one or more regions where the magnetic field as described herein is substantially uniform at an angle α as described herein; partially simultaneously with or subsequent to step b), step c) of at least partially curing the coating layer (x10) in a curing unit (x40) as described herein; Step c) is followed by a step d) of applying a second radiation-curable coating composition comprising second platelet-shaped magnetic or magnetizable pigment particles, said second radiation-curable coating composition being in a first liquid state to form a second coating layer (x11), said second coating layer (x11) being adjacent to (FIG. 3E) or spaced apart from (not shown) coating layer (x10), said second radiation-curable coating composition being the same as or different from the radiation-curable coating composition of step a); Step e) of exposing the second coating layer (x11) to the magnetic field of a second magnetic field generator in one or more areas where the second magnetic field is uniform to orient at least a portion of the second platelet-shaped magnetic or magnetizable pigment particles, wherein a substrate (x20) supporting the second coating layer (x11) is provided in said one or more areas at an angle α' between the second coating layer (x11) and a tangent to the magnetic field lines of the second magnetic field in said one or more areas where the magnetic field is uniform, the angle α' being greater than 0° and less than 30°. step e) in which the second magnetic field generator is the same as or different from the magnetic field generator of step b), and α' is different from α; partially simultaneously with or subsequent to step e) of exposing the second coating layer (x11) to a second magnetic field generating device, step f) of at least partially curing the second coating layer (x11) in a curing unit (x40) so as to at least partially fix the position and orientation of the second platelet-shaped magnetic or magnetizable pigment particles in the second coating layer (x11) and to produce an at least partially cured second coating layer (x11); Includes.

[0108] Suitable curing units (x40) include equipment for UV-visible curing units equipped with high-power light-emitting diode (LED) lamps or arc discharge lamps such as medium-pressure mercury arc (MPMA) or metal vapor arc lamps as actinic radiation sources. The selective curing units (x50) described herein may be equipped with one or more fixed or removable photomasks containing one or more voids corresponding to the pattern to be formed as part of the coating layer. One or more selective curing units (x50) may be addressable, such as a scanning laser beam as disclosed in EP 2 468 423, an array of light-emitting diodes (LEDs) as disclosed in WO 2017 / 021504, or an actinic radiation LED source (x41) comprising an array of individually addressable actinic radiation emitters as disclosed in co-pending patent application PCT / EP2019 / 087072.

[0109] According to one embodiment, wherein the security document or decorative article comprises a substrate (x20) as described herein, one or more OELs as described herein, and one or more patterns as described herein between the substrate (x20) and the one or more OELs, ​​each of which independently has the shape of an indicium, the method described herein comprises the step of applying a composition in the form of one or more patterns having the shape of an indicium, said step being performed before step a) as described herein. The step of applying a composition in the form of one or more patterns as described herein may be performed by a non-contact fluid micro-dispensing process such as curtain coating, spray coating, aerosol jet printing, electrohydrodynamic printing, and inkjet printing, or may be performed by a printing process selected from the group consisting of offset printing, screen printing, rotogravure printing, flexography printing, and intaglio printing (also referred to in the art as engraved copperplate printing and engraved steel die printing).

[0110]

[0109] The present specification also describes a printing apparatus comprising one or more printing units, one or more magnetic field generating devices (x30), and one or more curing units (x40), wherein the one or more printing units, one or more magnetic field generating devices (x30) and one or more curing units (x40) are arranged in sequential and alternating fixed positions such that a fixed magnetic field generating device (x30) is arranged after a fixed printing unit and before a fixed curing unit.

[0111]

[0110] Also described herein is a printing apparatus comprising a rotating magnetic cylinder and one or more magnetic field generating devices (x30) as described herein, wherein the one or more magnetic field generating devices (x30) are mounted in circumferential or axial grooves of a printing assembly comprising a rotating magnetic cylinder and a flatbed printing unit and one or more magnetic field generating devices (x30) as described herein, and the one or more magnetic field generating devices (x30) are mounted in recesses in the flatbed printing unit.

[0112] The rotating magnetic cylinder is adapted for use in or in conjunction with or to be part of a printing or coating apparatus and for supporting one or more of the magnetic field generating devices (x30) described herein. In one embodiment, the rotating magnetic cylinder is part of a rotary, sheet-fed or web-fed industrial printing press operating continuously at high speed printing.

[0113]

[0112] The flatbed printing unit is adapted to be used in or in combination with or be part of a printing or coating apparatus and to support one or more of the magnetic field generating devices (x30) described herein. In one embodiment, the flatbed printing unit is part of a discontinuously operating sheet-fed press.

[0114] A printing apparatus comprising a rotating magnetic cylinder as described herein or a flatbed printing unit as described herein may include a substrate feeder for supplying a substrate as described herein having thereon a coating layer (x10, x11) comprising platelet-shaped magnetic or magnetizable pigment particles as described herein. In an embodiment of a printing apparatus comprising a rotating magnetic cylinder as described herein, the substrate is supplied by the substrate feeder in the form of a sheet or web. In one embodiment of a printing apparatus comprising a flatbed printing unit as described herein, the substrate is supplied in the form of a sheet.

[0115] A printing apparatus comprising a rotating magnetic cylinder as described herein or a flatbed printing unit as described herein may comprise a coating or printing unit for applying a radiation curable coating composition comprising platelet-shaped magnetic or magnetizable pigment particles as described herein onto a substrate (x20) as described herein. In one embodiment of a printing apparatus comprising a rotating magnetic cylinder as described herein, the coating or printing unit operates according to a rotary continuous process. In one embodiment of a printing apparatus comprising a flatbed printing unit as described herein, the coating or printing unit functions according to a linear discontinuous process.

[0116]

[0115] A printing apparatus comprising a rotating magnetic cylinder as described herein or a flatbed printing unit as described herein may also comprise a curing unit (x40) as described herein for at least partially curing a radiation curable coating composition comprising platelet-shaped magnetic or magnetizable pigment particles that are magnetically oriented by a magnetic field generating device (x30) as described herein, thereby fixing the orientation and position of the pigment particles to produce one or more OELs as described herein.

[0117] example

[0116] Examples and comparative examples were carried out by using UV-Vis curable screen printing inks of the formulations shown in Table 1 and the first and second magnetic assemblies described below. [Table 1]

[0118]

[0117] Examples E1 to E8 according to the invention exhibited a striking visual appearance when tilted about the horizontal / latitudinal axis, which was seen as a sharp and contrasting switch-on / switch-off effect of luminance, consisting of an increase in luminance value to reach a luminance maximum, followed by a decrease in said luminance within viewing / observation angles of about -45° and about +45°.

[0119] Magnetic field generator for biaxial alignment (Figure 5)

[0118] The pigment particles were biaxially oriented using a magnetic assembly (530) which included nine bar dipole magnets (M1 to M9).

[0120] Each of the nine bar dipole magnets (M1-M9) had the following dimensions: 100 mm (L1) x 10 mm (L2) x 10 mm (L3). The magnetic field generator (530) was embedded in a non-magnetic holder (not shown) made of polyoxymethylene (POM) with dimensions of 250 mm x 150 mm x 12 mm. The nine bar dipole magnets (M1-M9) were made of NdFeB N40.

[0121]

[0120] The nine bar dipole magnets (M1 to M9) were arranged in a row at a distance (d1) of approximately 10 mm from each other, and the top surfaces of the nine bar dipole magnets (M1 to M9) were flush with each other. The magnetic axis of each of the nine bar dipole magnets (M1 to M9) was substantially parallel to the thickness (L3) of the magnet, and the magnetic directions of two adjacent magnets (M1 to M9) were pointing in opposite directions (alternating magnetization).

[0122]

[0121] As shown in Figures 5A1-5A2, the magnetic field was substantially uniform and the magnetic field lines were substantially coplanar in region A.

[0123] Magnetic field generation for uniaxial alignment Device (Figure 6)

[0122] The pigment particles were uniaxially oriented using a magnetic field generator (630) which included two rod dipole magnets (M1, M2) and two magnetic pole pieces (P1, P2).

[0124]

[0123] Each of the two bar dipole magnets (M1, M2) had the following dimensions: 40 mm (L1) x 40 mm (L2) x 10 mm (L3). The two bar dipole magnets (M1, M2) were made of NdFeB N40.

[0125]

[0124] The two bar dipole magnets (M1, M2) were at a distance (d1) of about 40 mm from each other, with the magnetic axis of each of the two bar dipole magnets (M1, M2) substantially parallel to the length (L1) of the magnet, and the magnetic directions of the two bar dipole magnets (M1, M2) pointing in the same direction.

[0126]

[0125] Each of the two pole pieces (P1, P2) had dimensions of 60 mm (L4) x 40 mm (L5) x 3 mm (L6). The two pole pieces (P1, P2) were made of iron (ARMCO®).

[0127]

[0126] The two bar dipole magnets (M1, M2) and the two pole pieces (P1, P2) were arranged to form a rectangular cube with a rectangular cubic void in the middle, the void consisting of an area A where a magnetic field was present, the magnetic field was substantially uniform and the magnetic field lines were substantially parallel to each other such that the distance (d2) between the two pole pieces (P1, P2) was about 40 mm, i.e. the distance (d2) between the two pole pieces (P1, P2) was the length (L1) of the two bar dipole magnets (M1, M2).

[0128] E1 to E5 and C1 to C3 (Figures 3A, 5, and 7) For each sample, the UV-Vis curable screen printing ink from Table 1 was applied onto a piece of PET (BG71 color laser printer & copier transparency from Folex, 100 micrometers thick, 45 mm x 30 mm) (520) to form a coating layer (40 mm x 25 mm) (510), in this case the application step was carried out on a laboratory screen printing apparatus using a 90T screen to form a coating layer (510) having a thickness of 20 μm.

[0129] While the coating layer (510) was still wet and at least partially uncured, the substrate (520) was placed on the center of a high-density polyethylene (HDPE) support plate (300 mm x 40 mm x 1 mm). The support plate supporting the substrate (520) and coating layer (510) was moved past a magnetic field generator (530) (as shown in FIG. 5) at a speed of approximately 10 cm / sec over a distance (d5) of approximately 20 mm between the surface of the magnetic field generator (530) facing the substrate (520) and the nearest edge of the coating layer (510), with the height between the nearest edge of the coating layer (510) and the bottom surface of the magnetic field generator (530) being half the length (½ x L1) of the bar dipole magnets (M1-M9). The support plate supporting the substrate (520) and the coating layer (510) moves simultaneously while adopting an angle α between the coating layer (510) and the tangent of the magnetic field lines of the magnetic field of the magnetic field generating device (530) within the magnetic field uniform region A, the angle α having values ​​of approximately 1° (E1), 5° (E2), 10° (E3), 20° (E4), 25° (E5), 30° (C1), 40° (C2), and 50° (C3).

[0130]

[0129] The coating layer (510) is cured by a curing unit (540) (UV LED lamp (FireFly 395 nm, 4 W / cm) from Phoseon) which is independently positioned above the substrate path at a distance (d4) of about 15 mm with respect to the center of the length (L1) of the bar dipole magnets (M1-M9), beside the space between the eighth and ninth bar dipole magnets (M8 and M9), and beside the ninth bar dipole magnet (M9) at a distance (d3) of about 10 mm, as shown in Figures 5A1 to 5A3. 2 )) at least partially cured.

[0131] E6 (Figure 3D, Figure 5, Figure 8) The UV-Vis curable screen printing inks of Table 1 were applied onto a piece of PET (BG71 color laser printer & copier transparency from Folex, 100 micrometers thick, 45 mm x 30 mm) (520) to form a first coating layer (510) having the shape of an "A" (6 mm) (510), the application step being carried out using a laboratory screen printing apparatus using a 90T screen to form a coating layer (510) approximately 20 μm thick.

[0132] While the coating layer (510) is still wet and not yet at least partially cured, the substrate (520) is attached to a support plate (300 mm x 40 mm) made of high density polyethylene (HDPE). x1mm The support plate supporting the substrate (520) and coating layer (510) was placed at the top center of the magnetic field generator (530) (as shown in FIG. 5 ). The support plate supporting the substrate (520) and coating layer (510) was moved at a speed of approximately 10 cm / sec beside the magnetic field generator (530) (as shown in FIG. 5 ), with a distance (d5) of approximately 20 mm between the surface of the magnetic field generator (530) facing the substrate (520) and the nearest edge of the coating layer (510), and the height between the nearest edge of the coating layer (510) and the bottom surface of the magnetic field generator (530) was half the length (½×L1) of the bar dipole magnets (M1-M9). The support plate supporting the substrate (520) and coating layer (510) was moved simultaneously while adopting an angle α between the coating layer (510) and the tangent to the magnetic field lines of the magnetic field of the magnetic field generator (530) in the uniform magnetic field region A, where the value of angle α was approximately 20°.

[0133]

[0132] The first coating layer (510) was at least partially cured by the curing unit (540) under the same conditions / locations as E1-E5 and C1-C3.

[0134]

[0133] For each sample, the UV-Vis curable screen printing ink of Table 1 was applied on top of the already applied coating layer (510) to form a second coating layer (511) having the shape of a "T" (6 mm), the application step being carried out using a laboratory screen printing apparatus using a 90T screen to form a coating layer (511) having a thickness of approximately 20 μm.

[0135]

[0134] While the second coating layer (511) was still wet and not yet at least partially cured, the substrate (520) was exposed to the magnetic field of the magnetic field generator (530) under the same conditions as the first coating layer (510), except that the angle α' was approximately 160°.

[0136]

[0135] The second coating layer (511) was at least partially cured by the curing unit (540) under the same conditions / locations as E1-E5 and C1-C3.

[0137] E7-E8 (Figure 3A, Figure 6, Figure 9) The UV-Vis curable screen printing inks of Table 1 were applied onto a piece of PET (BG71 color laser printer & copier transparency film from Folex, 100 micrometers thick, 45 mm x 30 mm) (620) to form a coating layer (40 mm x 25 mm) (610), the application step being carried out using a laboratory screen printing apparatus using a 90T screen to form a coating layer (610) having a thickness of approximately 20 μm.

[0138]

[0137] While the coating layer (610) was still wet and not yet at least partially cured, the substrate (620) was placed on top of the center of a high density polyethylene (HDPE) support plate (60 mm x 40 mm x 1 mm).

[0139]

[0138] The substrate (620) and the coating layer ( 6The support plate (610) supporting the coating layer (610) and the magnetic field generating device (630) in the region A where the magnetic field is uniform. Magnetic field The magnetic assembly (630) was placed in the center of the gap as shown in FIG. 6, with the angle α between the tangent of the field line and the magnetic field line being approximately 20°.

[0140]

[0139] For sample E7, after about 1 second, the coating layer (610) was at least partially cured by the curing unit (640) (UV LED lamp (FireFly 395 nm, 4 W / cm2 from Phoseon)), as shown in Figure 6B1.

[0141] For sample E8, following exposure to the magnetic field, the support plate supporting the substrate (620) and coating layer (610) was moved approximately 1 cm away from the magnetic assembly (630) at a distance (d i ) and the coating layer (610) was coated with Phoseon (FireTypeFireFlex 50x75mm, 395nm, 8W / cm), as shown in FIG. 2 ) for about 0.5 seconds to cure.

[0142] Correlation between the angle α during the orientation step and the elevation angle γ of the pigment particles in the coating layer (x10) The correlation between the angle α and the elevation angle γ in the aforementioned method was evaluated by measuring said elevation angle γ using conoscopic scatterometry according to the method disclosed in WO 2019 / 038371 and by measuring the elevation angle of a selection of five adjacent pigment particles on a cross-section of the coating layer (x10) in an SEM photograph (ZEISS EVO HD15 using the standard method of sample preparation by embedding in an epoxy matrix (Technicol 9461) with the following dimensions: 10 mm × 10 mm × 30 mm). The results are shown in Table 2. [Table 2]

[0143] Conoscopic scatterometry measurements were performed using a conoscopic scatterometer as described in WO 2019 / 038371, Figure 4A (taken from Eckhart Optics LLC, 5430 Jefferson Ct, White Bear Lake, MN 55110; http: / / eckop.com). The elevation angle γ was approximately 1 mm. 2 The measured values ​​were measured on the surface of the coating layer of approximately 1000 particles, i.e., the reported values ​​were averaged over approximately 1000 particles.

[0144] SEM measurements were performed on microtome sections of the samples (section plane perpendicular to the substrate surface and the thickness of the coating layer, perpendicular to the tilt axis, as shown in Figure 3) using an SEM microscope (ZEISS EVO HD15, magnification x500). The substrates bearing the coating layer were first individually embedded in epoxy resin (Technicol 9461), which was left to dry at room temperature for 24 hours before cutting and polishing the microtome slices to produce samples with the following dimensions: 10 mm x 10 mm x 30 mm. Reported values ​​were averaged over five particles.

[0145] As shown in Table 2, there was an excellent correlation between the angle α and the measured elevation angle γ.

[0146] Luminance at various observation angles θ

[0145] The samples were placed on paper substrates (black or white, respectively) and fixed with Scotch tape. As shown in Figure 10, the assemblies supporting the coating layers (x10, x11), PET substrate (x20), and paper substrate were individually placed on the tilt holder of an integrating sphere (1 m inner diameter, from Dongguan Yaoke Instrument). The assemblies were illuminated with an illumination source (a 30 W light bulb, 100% power) placed approximately 100 cm away from the PET substrate surface.

[0147] A camera (Nikon D800, Nikkor 105 / 2.8 ED lens, shutter speed 1 / 200 sec, aperture f / 36, ISO 6400) was placed on an imaginary line between the assembly and the illumination source, approximately 50 cm from the PET substrate. Images were captured at 3680 x 2456 pixels (TIFF).

[0148]

[0147] As shown in Figure 1, the holder supporting the assembly was rotated so that the holder was observed at observation angles α = 50°, 40°, 30°, 20°, 10°, 0°, -5°, -10°, -15°, -20°, -25°, -30°, -35°, -40°, -45°, -50°, -55°, -60°, -65°, and -70° (θ < 0° corresponds to the top edge of the assembly being close to the camera, and θ > 0° corresponds to the bottom edge of the assembly being close to the camera).

[0149]

[0148] The photographs thus obtained of E1 to E5 and C1 to C3 at different observation angles are shown in FIG. 7A, and the photographs thus obtained of E6 at different observation angles are shown in FIG.

[0150] The luminance of E1-E5, E7-E8, and C1-C3 was evaluated using Adobe Photoshop® by calculating the average luminance of a 100-pixel by 100-pixel area of ​​each individual assembly comprising the coating layer (x10, x11), the PET substrate (x20), and the paper substrate. Figure 7B shows a graph obtained by reporting the luminance of E1-E5 and C1-C3, and Figure 9 shows a graph obtained by reporting the luminance of E7-E8 at different observation angles θ varying from -50° to +70° (x-axis: observation angle θ [degrees, °]; y-axis: luminance (arbitrary units)). The luminance curves are asymmetric as a result of the poorly illuminated areas of the sphere due to the presence of the plate (P).

[0151]

[0150] As shown in Figures 7A and 7B, the optical effect layers E1 to E5 (0°<γ<30°, especially 5°≦γ<30°, 5°≦γ≦25°) showed an eye-catching effect and a readily observable increase in brightness to reach a maximum value within viewing / observation angles of approximately -45° and approximately +45°, followed by a decrease in said brightness value.

[0152]

[0151] E1 (1°) showed the maximum brightness at an observation angle θ of approximately -10°, E2 (5°) showed the maximum brightness at an observation angle θ of approximately -15°, E3 (10°) showed the maximum brightness at an observation angle θ of approximately -25°, E4 showed the maximum brightness at an observation angle θ of approximately -35°, and E5 showed the maximum brightness at an observation angle θ of approximately -40°.

[0153]

[0152] As shown in Figure 8, the first coating layer of E6 having an "A" shape (510 in Figure 5, 310 in Figure 3D) can be seen at an observation angle of about 0° to about +50° with a maximum brightness at an observation angle of about +40°, while the second / top coating layer having a "T" shape (511 in Figure 5, 311 in Figure 3D) can be seen at an observation angle of -15° to about -65° with a maximum brightness at an observation angle of about -35°.

[0154]

[0153] As shown in Figure 9A (black substrate) and Figure 9B (white substrate), E7-E8 showed a readily observable increase and decrease in luminance with a luminance maximum at an observation angle θ of -(20° to 25°) for E7 and -(10° to 15°) for E8.

Claims

1. A security document or decorative article comprising a substrate (x20) having a two-dimensional surface and one or more optical effect layers (OEL) on said substrate (x20), said one or more optical effect layers (OEL) comprising magnetically oriented platelet-shaped magnetic or magnetizable pigment particles having a major axis X and in an at least partially cured coating layer (x10), the orientation of the platelet-shaped pigment particles is defined by a platelet vector, which is a vector parallel to the major axis X of the pigment particle, the platelet vectors of adjacent platelet-shaped magnetic or magnetizable pigment particles being substantially parallel to each other; The platelet vector of the platelet-shaped magnetic or magnetizable pigment particle is angled at an elevation angle γ relative to the two-dimensional surface of the substrate (x20) at the location of the pigment particle, and the elevation angle γ is: greater than 0° and less than 30° (0°<γ<30°) or greater than 150° and less than 180° (150°<γ<180°), whereby said one or more optical effect layers (OEL) exhibit an increase in luminance reaching a luminance maximum and a decrease in luminance within a viewing angle of -45° to +45° of said substrate (x20), Security documents or decorations.

2. 2. A security document or decorative item according to claim 1, wherein at least a portion of said platelet-shaped magnetic or magnetisable particles are constituted by platelet-shaped optically variable magnetic or magnetisable pigment particles.

3. 2. A security document or decorative item according to claim 1, wherein at least a portion of said platelet-shaped magnetic or magnetisable particles are constituted by platelet-shaped magnetic or magnetisable pigment particles exhibiting a metallic colour.

4. A security document or decorative item according to any one of claims 1 to 3, wherein said platelet-shaped magnetic or magnetisable particles are substantially parallel to one another.

5. 5. The security document or decorative article according to any one of claims 1 to 4, further comprising one or more indicia, said one or more indicia being present between said substrate (x20) and said one or more optical effect layers (OEL).

6. The one or more optical effect layers (OEL) comprise magnetically oriented platelet-shaped magnetic or magnetizable pigment particles in the at least partially cured coating layer (x10) and magnetically oriented second platelet-shaped magnetic or magnetizable pigment particles in an at least partially cured second coating layer (x11), wherein the at least partially cured second coating layer (x11) at least partially or completely overlaps the at least partially cured coating layer (x10), or the at least partially cured second coating layer (x11) is adjacent to the at least partially cured coating layer (x10), or 6. The security document or decorative article according to any one of claims 1 to 5, wherein a second, also partially cured coating layer (x11) is spaced apart from the at least partially cured coating layer (x10), and wherein the platelet vectors of the second platelet-shaped magnetic or magnetisable pigment particles are angled in the at least partially cured second coating layer (x11) at the position of the pigment particles relative to the two-dimensional surface of the substrate (x20) by a further elevation angle γ', wherein the further elevation angle γ' is greater than 0° and less than 30° (0°<γ'<30°) or greater than 150° and less than 180° (150°<γ'<180°), and wherein the elevation angle γ and the further elevation angle γ' are different from each other and / or are not coplanar.

7. 7. The security document or ornament according to any one of claims 1 to 6, wherein said elevation angle γ is in the range of approximately 5° to less than 30° (5°≦γ<30°) or greater than 150° to approximately 175° (150°<γ≦175°).

8. 1. A method for producing an optical effect layer (OEL) on a substrate (x20) having a two-dimensional surface, comprising: a) applying a radiation-curable coating composition comprising platelet-shaped magnetic or magnetizable pigment particles onto a surface of a substrate (x20), said radiation-curable coating composition being in a first liquid state to form a coating layer (x10); b) exposing the coating layer (x10) to a magnetic field of a magnetic field generator (x30) in one or more regions where the magnetic field is substantially uniform, so as to orient at least a portion of the platelet-shaped magnetic or magnetizable pigment particles, wherein the substrate (x20) supporting the coating layer (x10) is provided in the one or more regions where the magnetic field is substantially uniform, and the angle α between the coating layer (x10) and a tangent to the magnetic field lines of the magnetic field in the one or more regions where the magnetic field is substantially uniform is greater than 0° and less than 30° (0°<α<30°) or greater than 150° and less than 180° (150°<α<180°); c) partially simultaneously with step b) or after step b), at least partially curing the coating layer (x10) in a curing unit (x40) so as to at least partially fix the position and orientation of the platelet-shaped magnetic or magnetizable pigment particles in the coating layer (x10) and to produce the at least partially cured coating layer (x10); Including, the orientation of the platelet-shaped pigment particles is defined by a platelet vector, which is a vector parallel to a major axis X of the pigment particle, the platelet vectors of adjacent platelet-shaped magnetic or magnetizable pigment particles being substantially parallel to each other, and the platelet vectors of the platelet-shaped magnetic or magnetizable pigment particles are angled at an elevation angle γ with respect to the two-dimensional surface of the substrate (x20) at the location of the pigment particle, the elevation angle γ being greater than 0° and less than 30° (0°<γ<30°) or greater than 150° and less than 180° (150°<γ<180°), method.

9. 9. The method of claim 8, wherein the platelet-shaped magnetic or magnetizable pigment particles have a second major axis Y, the orientation of the platelet-shaped pigment particles is further defined by a second platelet vector, the second platelet vector being a vector parallel to the second major axis Y of the pigment particle, and wherein step b) of exposing the coating layer (x10) is performed to biaxially orient at least a portion of the platelet-shaped magnetic or magnetizable pigment particles, such that the platelet vectors of adjacent platelet-shaped magnetic or magnetizable pigment particles are substantially parallel to each other and the second platelet vectors of adjacent platelet-shaped magnetic or magnetizable pigment particles are substantially parallel to each other.

10. 10. The method of claim 9, wherein step c) occurs partially simultaneously with step b).

11. the optical effect layer (OEL) comprises the at least partially cured coating layer (x10) comprising the platelet-shaped magnetic or magnetizable pigment particles, and at least partially on the at least partially cured coating layer (x10) an at least partially cured second coating layer (x11) comprising second platelet-shaped magnetic or magnetizable pigment particles, wherein the orientation of each of the second platelet-shaped pigment particles is defined by a platelet vector, which is a vector parallel to the major axis X of the second platelet-shaped pigment particle, and the platelet vectors of adjacent second platelet-shaped magnetic or magnetizable pigment particles are substantially parallel to each other, the platelet vector of the second platelet-shaped magnetic or magnetizable pigment particle is angled with respect to the two-dimensional surface of the substrate (x20) at the location of the pigment particle by a further elevation angle γ′ that is greater than 0° and less than 30° (0°<γ′<30°) or greater than 150° and less than 180° (150°<γ′<180°), wherein the elevation angle γ and the further elevation angle γ′ are different from each other and / or are not coplanar, The method comprises: following step c), a step d) of at least partially or completely applying on the at least partially cured coating layer (x10) a second radiation-curable coating composition comprising the second platelet-shaped magnetic or magnetizable pigment particles, the second radiation-curable coating composition being in a first liquid state to form a second coating layer (x11), the second radiation-curable coating composition being the same as or different from the radiation-curable coating composition of step a); a step e) of exposing the second coating layer (x11) to a second magnetic field of a second magnetic field generator in one or more areas where the second magnetic field is uniform, so as to orient at least a portion of the second platelet-shaped magnetic or magnetizable pigment particles, wherein the substrate (x20) supporting the second coating layer (x11) is provided in the one or more areas where the magnetic field is substantially uniform, and the angle α' between the second coating layer (x11) and a tangent to the magnetic field lines of the second magnetic field in the one or more areas where the magnetic field is uniform is greater than 0° and less than 30° (0°<α'<30°) or greater than 150° and less than 180° (150°<α'<180°), the second magnetic field generator being the same as or different from the magnetic field generator of step b), and α' being different from α; f) partially simultaneously with or after step e) of exposing the second coating layer (x11) to the second magnetic field, at least partially curing the second coating layer (x11) in a curing unit (x40) so as to at least partially fix the positions and orientations of the second platelet-shaped magnetic or magnetizable pigment particles in the second coating layer (x11) and to produce the at least partially cured second coating layer (x11); The method of any one of claims 8 to 10, further comprising:

12. the optical effect layer (OEL) comprises the at least partially cured coating layer (x10) comprising the platelet-shaped magnetic or magnetizable pigment particles and an at least partially cured second coating layer (x11) comprising second platelet-shaped magnetic or magnetizable pigment particles, wherein the orientation of each of the second platelet-shaped pigment particles is defined by a platelet vector, the platelet vector being a vector parallel to the major axis X of the second platelet-shaped pigment particle, the platelet vectors of adjacent second platelet-shaped magnetic or magnetizable pigment particles being substantially parallel to each other, and the at least partially cured second coating layer (x11) is adjacent to or spaced apart from the at least partially cured coating layer (x10), the platelet vectors of the second platelet-shaped magnetic or magnetizable pigment particles are angled in the at least partially cured second coating layer (x11) at the location of the pigment particles with respect to the two-dimensional surface of the substrate (x20) by a further elevation angle γ′ that is greater than 0° and less than 30° (0°<γ′<30°) or greater than 150° and less than 180° (150°<γ′<180°), wherein the elevation angle γ and the further elevation angle γ′ are different from each other and / or are not coplanar, The method comprises: following step c), a step d) of applying a second radiation-curable coating composition comprising the second platelet-shaped magnetic or magnetizable pigment particles, wherein the second radiation-curable coating composition is in a first liquid state to form a second coating layer (x11), the second radiation-curable coating composition being the same as or different from the radiation-curable coating composition of step a), the second coating layer (x11) being adjacent to or spaced apart from the at least partially cured coating layer (x10); a step e) of exposing the second coating layer (x11) to a second magnetic field of a second magnetic field generator in one or more regions where the magnetic field is uniform, so as to orient at least a portion of the second platelet-shaped magnetic or magnetizable pigment particles, wherein the substrate (x20) supporting the second coating layer (x11) is provided in the one or more regions where the magnetic field is substantially uniform, and the angle α' between the second coating layer (x11) and a tangent to the magnetic field lines of the second magnetic field in the one or more regions where the magnetic field is substantially uniform is greater than 0° and less than 30° (0°<α'<30°) or greater than 150° and less than 180° (150°<α'<180°), the second magnetic field generator being the same as or different from the magnetic field generator of step b), and α' being different from α; f) partially simultaneously with or after step e) of exposing the second coating layer (x11) to the second magnetic field, at least partially curing the second coating layer (x11) in a curing unit (x40) so as to at least partially fix the positions and orientations of the second platelet-shaped magnetic or magnetizable pigment particles in the second coating layer (x11) and to produce the at least partially cured second coating layer (x11); The method of any one of claims 8 to 10, further comprising:

13. 13. The method of claim 11 or 12, wherein the angle α' is within a range of approximately 5° to less than 30° (5°≦α'<30°) or greater than 150° to approximately 175° (150°<α'≦175°).

14. 14. The method according to claim 8, wherein the angle α is in the range of about 5° to less than 30° (5°≦α<30°) or greater than 150° to about 175° (150°<α≦175°).

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