EA045205B1

EA045205B1 - SECURED DOCUMENTS OR PRODUCTS CONTAINING LAYERS WITH AN OPTICAL EFFECT, CONTAINING MAGNETIC OR MAGNETIZABLE PIGMENT PARTICLES, AND METHODS FOR OBTAINING A SUBSTRATE WITH THE SAID LAYERS WITH AN OPTICAL EFFECT

Info

Publication number: EA045205B1
Application number: EA202390709
Authority: EA
Inventors: Евгений ЛОГИНОВ; Андреа Каллегари; Клод-Ален Деспланд
Original assignee: Сикпа Холдинг Са
Priority date: 2020-09-02
Filing date: 2021-08-30
Publication date: 2023-11-01

Description

Field of technology to which the invention relates

The invention relates to the field of optical effect layers (OELs) containing magnetically oriented magnetic or magnetizable pigment particles. In particular, the present invention provides security documents and decorative objects containing one or more optical effect layers (OELs), and methods for producing said OELs, as well as using said OELs as anti-counterfeiting agents on security documents or security articles, as well as for decorative purposes.

Prerequisites for creating the invention

It is known in the art to use paints, compositions, coatings or layers containing oriented magnetic or magnetizable pigment particles, in particular also optically variable magnetic or magnetizable pigment particles, to obtain security elements, for example in the field of security documents. Coatings or layers containing oriented magnetic or magnetizable pigment particles are disclosed, for example, in US 2570856, US 3676273, US 3791864, US 5630877 and US 5364689. Coatings or layers containing oriented magnetic color changing pigment particles that result in eye-catching optical effects used to protect security documents are disclosed in WO 2002/090002 A2 and WO 2005/002866 A1.

Security features, for example for security documents, can be broadly divided into covert security features on the one hand and explicit security features on the other hand. The protection provided by covert security features is based on the principle that they are difficult to detect and typically require specialized equipment and knowledge to detect, while overt security features are based on the concept of being easily detected by the unaided human senses; for example, such features may be visible and/or tactilely detectable and yet be difficult to manufacture and/or copy. However, the effectiveness of overt security features depends to a large extent on their ease of recognition as a security feature.

Magnetic or magnetizable pigment particles in printing inks or coatings allow the creation of magnetically induced images, patterns and/or designs through the application of an appropriate structured magnetic field causing local orientation of the magnetic or magnetizable pigment particles in the uncured/cured (i.e. wet) coating followed by hardening of the coating. The result is a stationary and stable magnetically induced image, pattern or design. Materials and techniques for orienting magnetic or magnetizable pigment particles in coating compositions are disclosed in US 2,418,479; US 2570856; US 3791864, DE2006848-A, US 3676273, US 5364689, US 6103361, EP 0406667 B1; US 2002/0160194; US 2004/0009308; EP 0710508 A1; WO 2002/09002 A2; WO 2003/000801 A2; WO 2005/002866 A1; WO 2006/061301 A1. In this way, it is possible to obtain magnetically induced patterns that are highly resistant to counterfeiting. The security element in question can only be manufactured with access to both magnetic or magnetizable pigment particles or associated ink and the specific technology used to print said ink and to orient said pigment in the printing ink.

As described, for example, in document WO 2015/018663 A1, it is known from the prior art that high contrast, brightness and reflectivity are required for overt security features containing magnetically oriented pigments or particles.

According to the magnetic orientation pattern of the magnetic or magnetizable pigment particles of the optical effect layer (OEL) and the viewing direction, said OEL can display bright and dark areas. The optical properties of specific OEL zones are directly dependent on the orientation of the magnetic or magnetizable pigment particles in the coating layer forming said OEL.

EP 2484455 B1 discloses OELs comprising co-visible zones of first and second cured coating compositions containing pigment particles oriented to simulate first and second curved surfaces. As disclosed in EP 2484455 B1 and the prior art cited therein in [003], in particular in WO 2004/007095 A2, coating compositions containing pigment particles oriented to simulate a curved surface create a specular reflection zone , which could be seen by an observer as a bright zone moving when the substrate carrying the coating composition is tilted (ie, when the viewing direction changes).

EP 2846932 B1 describes OELs with plate-like 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 changes. As disclosed in [0046], based on their shape, particles have maximum reflectivity (maximum projection area) in a direction perpendicular to their extended surface, and accordingly, when viewed orthogonally in an OEL image, light areas correspond to particles whose orientation is approximately the same with orientation according to

- 1 045205 surface, i.e. which have a small angle θ with respect to the OEL surface such that the incident light is essentially reflected back in the same (orthogonal) direction.

In the field of authentication of an apparent security element containing magnetically oriented plate-like magnetic or magnetizable pigment particles, the observer tilts said security element to verify its authenticity from the normal direction (i.e., viewing direction perpendicular to the surface of the substrate bearing the security element) to sliding angles (i.e. viewing directions substantially parallel to the surface of the substrate), i.e. from ±90°. However, non-expert observers, even if trained to operate the security feature, typically tilt the security feature within a narrower range, typically no more than ±45° from the normal to the substrate on which the feature is located. In addition, a person on the street may not always have the best lighting conditions to inspect/authenticate the security element.

The prior art does not provide any information about the orientation and suitable elevation angles of magnetically oriented particles to create OELs that exhibit a significant and observable change (ie, increase and decrease) in brightness when normally tilted by an observer during the process of authenticating said element.

Thus, there remains a need for optical effect layers (OELs) and methods for producing said OELs, said OELs exhibiting an attractive and easily recognizable appearance, exhibiting high contrast highly reflective (bright) and non-reflective (dark) areas at suitable viewing angles for a person on the street to easily authenticate the specified OEL.

Brief description of the invention

Accordingly, it is an object of the present invention to overcome the disadvantages of the prior art.

This is achieved by creating a security document or decorative object comprising a substrate (x20), wherein said substrate (x20) has a two-dimensional surface and one or more optical effect layers (OEL), wherein said one or more optical effect layers (OEL) contain magnetically oriented platelet magnetic or magnetizable pigment particles with a major X axis located in an at least partially cured layer (x 10) of the coating, wherein the orientation of the platelet pigment particles is determined by a platelet vector, which is a vector parallel to the major X axis of the particle , wherein the vector plates of adjacent plate-like magnetic or magnetizable pigment particles are substantially parallel to each other, and wherein the vector plates of the plate-like magnetic or magnetizable pigment particles are located relative to the two-dimensional surface of the substrate (x20) at particle positions at an elevation angle γ, wherein said angle elevation γ greater than 0° and less than 30° (0°<γ<30°) or greater than 150° and less than 180° (150°<γ<180°), preferably greater than or equal to approximately 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 from about 5° to about 25° (5°<γ<25°) or from approximately 155° to approximately 175° (155°<γ<175°), such that one or more optical effect layers (OEL) exhibit an increase in brightness to achieve a maximum brightness value and a decrease in brightness over a viewing angle range of -45° to + 45° substrate (x20).

One or more optical effect layers (OELs) described herein comprise uniaxial platelet magnetic or magnetizable pigment particles or contain biaxially oriented platelet magnetic or magnetizable pigment particles

Also described herein are the security documents or articles described herein further comprising one or more indicia, wherein said one or more indicia are present between a substrate (x20) and one or more optical effect layers (OELs).

Also described herein are the security documents or articles described herein, wherein one or more optical effect layers (OELs) comprise magnetically oriented lamellar magnetic or magnetizable pigment particles in at least a partially cured (x10) coating layer and comprise magnetically oriented second plate-like magnetic or magnetizable pigment particles in the at least partially cured second coating layer (x11), wherein either the at least partially cured second coating layer (x11) at least partially or completely overlaps the at least partially cured layer (x10 ) coating, either 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 distant from the at least partially cured coating layer (x10 ) of the coating, wherein the vector plates of the second plate-like magnetic or magnetizable pigment particles are located relative to the two-dimensional surface of the substrate (x20) at particle positions at an additional elevation angle γ' in the at least partially cured second layer (x11) of the coating, with the additional elevation angle γ ' more than 0° and less than 30° (0°<γ'<30°)

- 2 045205 or more than 150° and less than 180° (150°<γ'<180°), wherein the specified elevation angle γ and the additional elevation angle γ' differ from each other and/or are not coplanar.

Also described herein are methods for producing the optical effect layers (OELs) described herein and the optical effect layers (OELs) produced therefrom. Also described herein are methods for producing an optical effect layer (OEL) on a substrate (x20) with a two-dimensional surface, the method comprising the steps of:

a) applying to the surface of the substrate (x20) a radiation-curable coating composition containing lamellar magnetic or magnetizable pigment particles, said radiation-curable coating composition being in a first, liquid state, to form a coating layer (x10);

b) exposing a layer (x 10) of coating to the magnetic field of a device (x 30) generating a magnetic field in one or more areas in which the magnetic field is substantially uniform, with the orientation of at least a portion of the lamellar magnetic or magnetizable pigment particles, at wherein a substrate (x20) bearing a layer (x10) of coating is provided in said one or more regions in which the magnetic field is substantially uniform, with an angle α formed by the layer (x10) of coating and tangent to the magnetic field lines in one or more regions in which the magnetic field is substantially uniform, the angle being greater than 0° and less than 30° (0°<α<30°) or greater than 150° and less than 180° (150°<α<180°), preferably greater than or equal to about 5° and less than 30° (5°<α<30°) or greater than 150° and less than or equal to about 175° (150°<α<175°), more preferably in the range of about 5° to about 25° (5°<α<25°) or from about 155° to about 175° (155°<a<175°);

c) partially simultaneously with or subsequent to step b), the step of at least partially curing the coating layer (x 10) using a curing unit (x40) with at least partially fixing the position and orientation of the lamellar magnetic or magnetizable pigment particles in the layer (x 10) coating to produce at least a partially cured layer (x 10) of coating, wherein the orientation of the platelet pigment particles is determined by a platelet vector, which is a vector parallel to the major X axis of the particle, wherein the platelet vectors of adjacent platelet magnetic or magnetizable particles of pigment are substantially parallel to each other, and wherein the plate vectors of plate-like magnetic or magnetizable pigment particles are located relative to the two-dimensional surface of the substrate (x20) at particle positions at an elevation angle γ, wherein said elevation angle γ is greater than 0° and less than 30° (0° <γ<30°) or more than 150° and less than 180° (150°<γ<180°).

Step b) of exposing the layer (x 10) of the coating described herein can be performed with uniaxial orientation of at least a portion of the lamellar magnetic or magnetizable pigment particles such that the lamellar vectors of adjacent lamellar magnetic or magnetizable pigment particles are substantially parallel to each other. Alternatively, step b) of exposing the (x10) coating layer described herein can be performed with a biaxial orientation of at least a portion of the platelet magnetic or magnetizable pigment particles with a major X axis described herein and a second major Y axis, wherein the orientation is further defined by a second plate vector which is a vector parallel to the second major Y axis of the particle such that the plate vectors of adjacent plate magnetic or magnetizable pigment particles are substantially parallel to each other and the second plate vectors of said adjacent plate magnetic or magnetizable pigment particles are essentially parallel to each other.

Also described herein are methods for producing optical effect layers (OELs) comprising at least a partially cured coating layer (x10) containing platelet magnetic or magnetizable pigment particles, and an at least partially cured second coating layer (x11) containing second lamellar magnetic or magnetizable pigment particles, wherein said at least partially cured second coating layer (x11) may be located at least partially or entirely on or adjacent to said at least partially cured coating layer (x10) partially cured layer (x10) of the coating or be distant from it, while the orientation of each of the second lamellar pigment particles is determined by a vector plate, which is a vector parallel to the main axis X of the second lamellar pigment particles, while the vector plates of adjacent second lamellar magnetic or magnetizable pigment particles are substantially parallel to each other, and wherein the plate vectors of the second plate-like magnetic or magnetizable pigment particles are located relative to the two-dimensional surface of the substrate (x20) at particle positions at an additional elevation angle γ', which is greater than 0° and less than 30° ( 0°<γ'<30°) or more than 150° and less than 180° (150°<γ'<180°), wherein said elevation angle γ and the additional elevation angle γ' are different from each other and/or are not coplanar.

The present invention provides optical effect layer (OEL) substrates containing magnetically oriented magnetic or magnetizable pigment particles with specific

- 3 045205 different elevation angles to demonstrate high-contrast highly reflective (bright) and non-reflective (dark) areas when the angle is changed by a person from the street and in diffuse lighting conditions without the need for complex manipulations. Thus, a person on the street can easily authenticate the OELs described in this document.

Brief description of the figures

Security documents or articles containing one or more optical effect layers (OELs) described herein, and the methods described herein for producing said OELs on substrates (x20) are now described in more detail with reference to the drawings and specific embodiments implementations in which:

in fig. 1 is a schematic illustration of a front view of an OEL as seen by a person on the street, wherein said person on the street tilts the OEL around a tilt axis τ at viewing angles from -45° to +45° to easily authenticate the OEL on a two-dimensional surface substrate;

in fig. 2A schematically illustrates a platelet particle with its major X axis and its major Y axis;

in fig. 2B schematically illustrates uniaxially oriented lamellar particles, with the lamellar vectors (vectors parallel to the major X axis of the particle) of adjacent lamellar magnetic or magnetizable pigment particles being substantially parallel to each other. In fig. 2C schematically illustrates biaxially oriented platelet particles, wherein the platelet vectors (vectors parallel to the major X axis of the particle) of adjacent platelet magnetic or magnetizable pigment particles are substantially parallel to each other and the second platelet vectors (vectors parallel to the major Y axis of the particle) of adjacent plate-like magnetic or magnetizable pigment particles substantially parallel to each other;

in fig. 3A is a schematic cross-sectional illustration of an OEL comprising magnetically oriented platelet magnetic or magnetizable pigment particles in a coating layer (310) on a substrate (320);

in fig. 3B schematically illustrates an OEL in cross section (along a plane perpendicular to the tilt axis τ OEL) comprising one at least partially cured coating layer (310) containing lamellar magnetic or magnetizable pigment particles in one or more first zones (310-a) and platelet magnetic or magnetizable pigment particles in one or more second zones (310-b), wherein substantially all platelet magnetic or magnetizable pigment particles in one or more zones (310-a) have substantially the same elevation angle γ and substantially all platelet magnetic or magnetizable pigment particles in one or more zones (310-b) have essentially the same additional elevation angle γ', and the specified elevation angle γ and the additional elevation angle γ' are different from each other and/or are not coplanar;

in fig. 3C is a schematic cross-sectional illustration of an OEL comprising at least a partially cured coating layer (310) in which magnetically oriented platelet-like magnetic or magnetizable pigment particles are included, and an at least partially cured second coating layer (311) in which are magnetically embedded -oriented second lamellar magnetic or magnetizable pigment particles, wherein said at least partially cured second coating layer (311) partially overlaps at least partially cured coating layer (310), wherein substantially all of the lamellar magnetic or magnetizable pigment particles in at least the at least partially cured coating layer (310) have substantially the same elevation angle γ, and substantially all of the second plate-like magnetic or magnetizable pigment particles in the at least partially cured second coating layer (311) have substantially the same additional elevation angle γ', wherein said the elevation angle γ and the additional elevation angle γ' are different from each other and/or are not coplanar;

in fig. 3D schematically illustrates an OEL in cross section comprising at least a partially cured coating layer (310) in which magnetically oriented platelet-like magnetic or magnetizable pigment particles are included, and an at least partially cured second coating layer (311) in which are magnetically included -oriented second lamellar magnetic or magnetizable pigment particles, wherein said at least partially cured second coating layer (311) completely overlaps the at least partially cured coating layer (310), wherein all lamellar magnetic or magnetizable pigment particles at least partially cured coating layer (310) have substantially the same elevation angle γ, and all second plate-like magnetic or magnetizable pigment particles in the at least partially cured second coating layer (311) have substantially the same additional elevation angle γ', wherein said elevation angle γ and the additional elevation angle γ' differs from each other and/or is not coplanar;

in fig. 3E schematically illustrates a cross-sectional OEL comprising at least a partially cured coating layer (310) in which magnetically oriented

- 4 045205 lamellar magnetic or magnetizable pigment particles, and an at least partially cured second coating layer (311), in which magnetically oriented second lamellar magnetic or magnetizable pigment particles are included, said at least partially cured second coating layer adjacent to the at least partially cured coating layer (310), wherein all lamellar magnetic or magnetizable pigment particles in the at least partially cured coating layer (310) have substantially the same elevation angle γ and all second lamellar magnetic or magnetizable pigment particles at least the partially cured second coating layer (311) have substantially the same additional elevation angle γ', wherein said elevation angle γ and the additional elevation angle γ' are different from each other and/or are not coplanar;

in fig. 4A1 schematically illustrates a suitable magnetic field generating device (430) in cross section for uniaxial orientation of plate-like magnetic or magnetizable pigment particles in a coating layer (410) on a substrate (420), said device (430) consisting of a bar dipole magnet, with Here, the platelet magnetic or magnetizable pigment particles are exposed to the magnetic field (magnetic field lines are shown by lines with arrows pointing from the north pole to the south pole) of the magnetic field generating device (430) in one region in which the magnetic field is substantially uniform ( shown by a dotted rectangle A), and wherein a substrate (420) carrying a coating layer (410) is provided in said region A with an angle α;

in fig. 4A2 schematically illustrates a suitable magnetic field generating device (430) for uniaxial orientation of plate-like magnetic or magnetizable pigment particles in a coating layer (410) on a substrate (420), said device (430) consisting of two dipole bar magnets (M1, M2 ) with the same magnetic direction and an iron clamp (Y), whereby the plate-like magnetic or magnetizable pigment particles are exposed to the magnetic field (magnetic field lines are shown by lines with arrows pointing from the north pole to the south pole) of a bar dipole magnet (430) in one area , in which the magnetic field is substantially uniform (shown by the dotted rectangle A), and wherein the substrate (420) supporting the coating layer (410) is provided in the specified area A at a specific angle α;

in fig. 4B1 schematically illustrates (left) a suitable magnetic field generating device (430) and (right) a cross-section of said device (430) for biaxial orientation of at least a portion of plate-like magnetic or magnetizable pigment particles in a coating layer (410) on a substrate ( 420), said device (430) consisting of a linear arrangement of four dipole magnets (M1-M4), which are arranged in a staggered or zigzag pattern, wherein plate-like magnetic or magnetizable pigment particles are exposed to a magnetic field (magnetic field lines are shown lines with arrows pointing from the north pole to the south pole) of the device (430) generating a magnetic field, in one region in which the magnetic field is substantially uniform (shown by dotted rectangles A and A'), and wherein the substrate (420) , bearing the coating layer (410), is provided in the specified area A (or alternatively in the area A') with an angle α;

in fig. 4B2 schematically illustrates (left) a suitable magnetic field generating device (430) and (right) a cross-section of said device (430) for biaxial orientation of at least a portion of plate-like magnetic or magnetizable pigment particles in a coating layer (410) on a substrate ( 420), wherein said device (430) consists of two dipole magnets (M1, M2) with opposite magnetic direction, wherein plate-like magnetic or magnetizable pigment particles are exposed to a magnetic field (magnetic field lines are shown by lines with arrows pointing from the north pole to south pole) of the magnetic field generating device (430), in one region in which the magnetic field is substantially uniform (shown by dashed rectangles A and A'), and wherein a substrate (420) supporting a coating layer (410) is provided in said region A (or alternatively in said region A') with an angle α;

in fig. 4B3 schematically illustrates (left) a suitable magnetic field generating device (430) and (right) a cross-section of said device (430) for biaxial orientation of at least a portion of plate-like magnetic or magnetizable pigment particles in a coating layer (410) on a substrate ( 420), wherein the said device (430) consists of two dipole magnets (M1, M2) with the same magnetic direction, wherein the platelet magnetic or magnetizable pigment particles are exposed to a magnetic field (magnetic field lines are shown by lines with arrows pointing from the north pole to south pole) of the magnetic field generating device (430) in one region in which the magnetic field is substantially uniform (shown by dashed rectangle A), and wherein a substrate (420) carrying a coating layer (410) is provided in said region A with angle α;

- 5 045205 in Fig. 4B4 schematically illustrates (left) a suitable magnetic field generating device (430) and a top view (right) of said device (430) for biaxially orienting at least a portion of lamellar magnetic or magnetizable pigment particles in a coating layer (410) on a substrate (420). ), wherein said device (430) consists of a Halbach assembly containing five dipole magnets (M1-M5), wherein plate-like magnetic or magnetizable pigment particles are exposed to a magnetic field (magnetic field lines are shown by lines with arrows pointing from the north pole to the south pole pole) of the magnetic field generating device (430) in one region in which the magnetic field is substantially uniform (shown by the dotted parallelepiped A), and wherein a substrate (420) carrying a coating layer (410) is provided in said region A with angle α;

in fig. 4B5 schematically illustrates a suitable magnetic field generating device (430) in cross section for biaxial orientation of at least a portion of plate-like magnetic or magnetizable pigment particles in a coating layer (410) on a substrate (420), said device (430) consisting of an assembly Halbach cylinder containing four structures, each containing a magnetic rod (M1-M4) surrounded by an electromagnetic coil (not shown), wherein plate-like magnetic or magnetizable pigment particles are exposed to a magnetic field (magnetic field lines are shown by lines with arrows pointing away from north pole to south pole) of the magnetic field generating device (430) in one region in which the magnetic field is substantially uniform (shown by dashed rectangle A), and wherein a substrate (420) supporting a coating layer (410) is provided in the specified area A with angle α;

in fig. 4B6 schematically illustrates (left) a suitable magnetic field generating device (430) and a top view (right) of said device (430) for biaxially orienting at least a portion of lamellar magnetic or magnetizable pigment particles in a coating layer (410) on a substrate (420). ), wherein said device (430) consists of an assembly of eight dipole bar magnets (M1-M8), said assembly comprising a first set containing a first dipole bar magnet (M4) and two second dipole bar magnets (M1, M6), a second set , containing a first dipole bar magnet (M5) and two second dipole bar magnets (M3; M8), and a first pair of third dipole bar magnets (M2, M7), wherein the plate magnetic or magnetizable pigment particles are exposed to a magnetic field (magnetic lines fields are shown by lines with arrows pointing from the north pole to the south pole) of the magnetic field generating device (430), in one region in which the magnetic field is substantially uniform (shown by the dashed rectangle A), and wherein the substrate (420) a supporting coating layer (410) is provided in said area A at a specific angle α;

in fig. 5A schematically illustrates an oblique view (FIG. 5A1) and cross section (FIGS. 5A2-3) of a suitable magnetic field generating device (530) for biaxially orienting lamellar magnetic or magnetizable pigment particles contained in a coating layer (510) on a substrate ( 520), and devices (540) for curing. The magnetic field generating device (530) contains nine dipole bar magnets (M1-M9) with alternating north-south magnetic directions, which are arranged in a row, whereby plate-like magnetic or magnetizable pigment particles are exposed to the magnetic field (for illustrative purposes, magnets M3-M9 are shown in Fig. 5A2, the magnetic field lines are shown by lines with arrows pointing from the north pole to the south pole) of the magnetic field generating device (530), in one region in which the magnetic field is substantially uniform (shown by the dotted parallelepiped A), and wherein a substrate (520) carrying a coating layer (510) is provided in said region A with an angle α. In fig. 5A3 illustrates a method in which the at least partial curing step is carried out partially simultaneously with the magnetic alignment step by means of a curing device (540);

in fig. 6A, B schematically illustrate front views of a magnetic field generating device (630) for uniaxially aligning lamellar magnetic or magnetizable pigment particles contained in a coating layer (610) on a substrate (620) and a curing device (640). The magnetic field generating device (630) comprises two dipole bar magnets (M1, M2) and two pole pieces (P1, P2) arranged in a rectangular array, wherein the platelet magnetic or magnetizable pigment particles are exposed to the magnetic field (magnetic field lines). fields are shown by lines with arrows pointing from the north pole to the south pole) of the magnetic field generating device (630) in one region in which the magnetic field is substantially uniform (shown by dashed rectangle A), and wherein the substrate (620) the supporting layer (610) of the coating is provided in the specified area A with an angle α. In fig. 6B1 illustrates a method in which the at least partial curing step is carried out partially simultaneously with the magnetic orientation step, and FIG. 6B2 illustrates a method in which the at least partial curing step is carried out after the magnetic alignment step;

- 6 045205 in Fig. 7A shows photographs of OELs, said OELs being obtained using the method and apparatus shown in FIG. 5;

in fig. 7B illustrates the OEL luminance value curves containing the biaxially oriented pigment particles shown in FIG. 7A and having different elevation angles γ, wherein the OELs are printed on a transparent PET substrate located on a black substrate. The y-axis represents the OEL luminance in arbitrary units calculated for 100x100 pixel regions of the OEL images, with the x-axis representing the viewing angles θ;

in fig. 8 shows photographs of OEL containing biaxially oriented pigment particles and similar to FIG. 3D, the indicated OELs are obtained using the method and apparatus shown in FIG. 5;

in fig. 9A, B illustrate the luminance curves of two OELs containing uniaxial pigment particles with an elevation angle γ of approximately 20°, with the OELs printed on a transparent PET substrate located on a black substrate (Fig. 9A) or on a white substrate (Fig. 9B). . The y-axis represents the OEL luminance in arbitrary units calculated for 100x100 pixel regions of the OEL images, with the x-axis representing the viewing angles θ;

in fig. 10 schematically illustrates the apparatus for obtaining photographs shown in FIG. 7A and 8, at different viewing angles θ, the device comprising an integrating sphere (IS), an illumination source (L), a camera (C) and a movable sample holder (H) for samples (S), wherein the camera (C) and the movable holder ( H) are fixed on the plate (P) to change the viewing angle θ of the sample.

The magnetic field lines (shown by lines with arrows pointing from the north pole to the south pole) of the magnetic field generating device (x30) shown in the figures for illustrative purposes were obtained by simulation, said magnetic field simulations being carried out using Vizimag 3.19 software.

Detailed description

Definitions.

To interpret the meaning of the terms discussed in the description and set forth in the claims, the following definitions should be used.

As used herein, the term at least one is intended to mean one or more, such as one, or two, or three.

As used herein, the terms approximately and essentially mean that the specified amount or value may have a specific defined value or some other value adjacent to it. In general, terms approximately and substantially denoting a specific value are intended to indicate a range within ±5% of the value. As one example, the phrase approximately 100 denotes the range 100 ±5, i.e. range from 95 to 105. In general, when using the term, it is approximately possible to expect that similar results or effects according to the present invention can be obtained within a range of ±5% of the specified value.

The term substantially parallel refers to a deviation of no more than 2° on average across the surface of the coating layer of at least 1 mm ² in area, or at least about 100 particles, from parallel alignment.

As used herein, the term and/or means that either all or only one of the elements of a specified group may be present. For example, A and/or B will mean only A or only B, or both A and B. In the case of only A, this term also covers the possibility of the absence of B, i.e. only A, but not B.

The term containing as used herein is non-exclusive and subject to change. Thus, for example, a coating composition containing compound A may contain other compounds in addition to A. However, the term containing also covers, as in its particular embodiment, the more restrictive meanings consisting essentially of and consisting of, so that, for example, a mixture containing A, B and optionally C may also (substantially) consist of A and B or (mostly) consist of A, B and C.

The term optical effect layer (OEL) as used herein means a coating layer that contains oriented magnetic or magnetizable pigment particles, wherein said magnetic or magnetizable pigment particles are oriented by a magnetic field, and wherein the oriented magnetic or magnetizable pigment particles are fixed/immobilized in their orientation and position (i.e. after curing) to form a magnetically induced image.

The term coating composition refers to any composition that is capable of forming an optical effect layer (OEL) on a solid support and that can be applied preferably, but not exclusively, by printing. The coating composition contains platelet magnetic or magnetizable pigment particles described herein and a binder described herein.

- 7 045205

As used herein, the term wet refers to a coating layer that is at least not yet cured, for example a coating in which the platelet magnetic or magnetizable pigment particles are still able to change their positions and orientations due to external forces acting on them.

The term secure document refers to a document that is generally protected from forgery or falsification by at least one security feature. Examples of protected documents include, but are not limited to, valuable documents and valuable commercial items.

The term security feature is used to refer to an image, design or graphic element that can be used for authentication purposes.

When the present description concerns preferred embodiments/features, combinations of these preferred embodiments/features should also be considered disclosed as long as the combination of preferred embodiments/features is technically meaningful.

The present invention provides security documents and decorative objects comprising a substrate (x20), wherein said substrate (x20) has a two-dimensional surface and one or more optical effect layers (OELs), wherein said OELs are based on magnetically oriented plate-like magnetic or magnetizable pigment particles , wherein the orientation of the substrate (x20) is determined by the substrate vector, which is a local normal vector to the substrate (x20) perpendicular to the two-dimensional surface of the substrate (x20) at the corresponding position of one or more optical effect layers (OELs).

Typical examples of decorative objects include, but are not limited to, luxury goods, cosmetic packaging, automobile parts, electronic/electrical appliances, furniture, and nail products. Alternatively, one or more OELs described herein can be applied to a supporting substrate, such as, for example, a label, and then in a separate step transferred to a decorative object.

Protected documents include, but are not limited to, valuable documents and valuable commercial items. Typical examples of valuable documents include, but are not limited to, banknotes, legal documents, tickets, cheques, vouchers, stamps and excise stamps, agreements, etc., identification documents such as passports, identity cards, visas, driving licenses, bank cards , credit cards, transaction cards, access documents or cards, entrance tickets, public transport tickets, higher education certificates or academic titles, etc., preferably banknotes, identity documents, title deeds , driver's licenses and credit cards. The term high value commercial item refers to packaging materials, in particular for cosmetic products, nutraceutical products, pharmaceutical products, alcoholic beverages, tobacco products, beverages or food products, electrical/electronic products, textiles or jewelry, i.e. products that must be protected against counterfeiting and/or illegal reproduction to ensure the authenticity of the contents of the packaging, such as genuine medicines. Examples of these packaging materials include, but are not limited to, labels such as product authentication labels, tamper-evident labels and seals. It should be noted that the disclosed substrates, security documents and decorative objects are provided solely for purposes of example and without limiting the scope of the present invention. Alternatively, one or more OELs described herein can be applied to an auxiliary substrate, such as, for example, a security thread, security strip, foil, decal, window or label, and then in a separate step transferred to the security document.

The form of one or more OELs described herein may be continuous or discontinuous. In one embodiment, the shape of the one or more OELs is independently one or more of characters, dots, and/or lines. For embodiments in which secure documents and decorative objects contain multiple, i.e. two, three, etc., OELs, said OELs may be adjacent to each other or separated.

As mentioned herein, the attractive OELs described herein allow an observer to easily authenticate them when tilted at an angle from about -45° to about +45°. The attractive appearance is manifested by a sharp and contrasting brightness on/off effect and consists of increasing the brightness value until the maximum brightness value is reached, and then decreasing said brightness over a viewing/viewing angle range of approximately -45° to approximately +45°, with said change brightness can be observed with the naked eye.

As shown in FIG. 1, a person on the street typically tilts the OEL around the tilt axis τ at viewing angles from -45° to +45°, wherein said OEL can be tilted around: i) the vertical/longitudinal axis (up/down movement) or ii) around the horizontal/ latitude axis (movement left/right). However, any other tilt axes τ can be used.

- 8 045205

For embodiments in which the security document or decorative object contains a single OEL, an attractive appearance can be seen when tilted about: i) a vertical/longitudinal axis or ii) about a horizontal/latitudinal axis.

For embodiments in which the security document or decorative object contains at least two OELs, the attractive appearance of both of the two OELs can be seen when tilted about: i) a vertical/longitudinal axis or ii) about a horizontal/latitudinal axis; alternatively, the attractive appearance of one of the two OELs can be seen when tilted about a vertical/longitudinal axis, while the attractive appearance of the other of the two OELs can be seen when tilted about a horizontal/latitudinal axis.

The lamellar magnetic or magnetizable pigment particles are contained in the radiation-curable coating composition described herein, as well as in the (x10) coating layer, as well as in the at least partially cured (x10) coating layer. As mentioned herein, the methods described herein include step c) of at least partially curing the (x 10) coating layer into a second state in which platelet magnetic or magnetizable pigment particles are fixed in their current positions and orientations and cannot move or rotate more in the specified layer. As used herein, the term at least partial curing of a coating layer (x 10) means that the platelet magnetic or magnetizable pigment particles are fixed/immobilized in their positions and orientations and can no longer move or rotate (also referred to in the art as particle fixation).

As mentioned herein, one or more optical effect layers (OELs) described herein comprise magnetically oriented platelet-like magnetic or magnetizable pigment particles in an at least partially cured coating layer. Preferably, the platelet magnetic or magnetizable pigment particles described herein are present in an amount of from about 5 wt% to about 40 wt%, more preferably from about 10 wt% to about 30 wt%, the weight percentage being calculated based on the total weight of the at least partially cured coating layer. Preferably, the platelet magnetic or magnetizable pigment particles described herein are present in an amount of from about 5 wt% to about 40 wt%, more preferably from about 10 wt% to about 30 wt%, the weight percentage being calculated based on the total weight of the radiation-curable coating layer described herein.

The lamellar magnetic or magnetizable pigment particles described herein are defined as having, due to their non-spherical shape, anisotropic reflectivity to incident electromagnetic radiation to which the cured binder material is at least partially transparent. As used herein, the term anisotropic reflectivity means that the fraction of incident radiation at a first angle that is reflected by a particle in some (viewing/observation) direction (second angle) depends on the orientation of the particles, i.e., that a change in particle orientation with respect to the first angle may result in different amounts of reflection in the viewing/observation direction. Preferably, the platelet magnetic or magnetizable pigment particles described herein have anisotropic reflectivity with respect to incident electromagnetic radiation over some or all of the wavelength range from about 200 to about 2500 nm, more preferably from about 400 to about 700 nm, so that changing the orientation of a particle causes a change in the reflection of that particle in a certain direction. As is known to one skilled in the art, the magnetic or magnetizable pigment particles described herein differ from conventional pigments in that said conventional pigment particles have the same color and reflectivity regardless of particle orientation, whereas magnetic or magnetizable pigment particles , described herein, have either reflectivity, color, or both, which depends on the orientation of the particles. Unlike needle-shaped pigment particles, which can be considered as one-dimensional particles, platelet pigment particles have an X-axis and a Y-axis defining the plane of the predominant expansion of the particles (Fig. 2A). In other words, and as shown in FIG. 2A, the lamellar pigment particles can be considered as two-dimensional particles due to the large aspect ratio of their sizes, with the X and Y dimensions being substantially larger than the Z dimension. The lamellar pigment particles are also called oblate particles or flakes in the art. Such pigment particles may be described by a major X axis corresponding to the largest dimension intersecting the pigment particle and a second major Y axis perpendicular to X which also lies within said pigment particles.

The orientation of plate-like magnetic or magnetizable pigment particles is determined by the plate-vector, which is a vector parallel to the main X-axis of the particle, while

- 9 045205 the stink vectors of adjacent lamellar magnetic or magnetizable pigment particles are substantially parallel to each other (see Fig. 2B), and the lamellar vectors of the lamellar magnetic or magnetizable pigment particles are located relative to the two-dimensional surface of the substrate (x20) at the positions of the particles under elevation angle γ described in this document. The elevation angle γ 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 or equal to approximately 5° and less than 30° (5°<γ<30°) or greater than 150° and less than or equal to approximately 175° (150°<γ<175°). More preferably, the elevation angle γ ranges from about 5° to about 25° (5°<γ<25°) or from about 155° to about 175° (155°<γ<175°).

OELs containing platelet magnetic or magnetizable pigment particles with an elevation angle of 0° are indistinguishable and can be imitated by non-magnetic pigments typically dispersed in solvent-based paints, with the pigments being forced to adopt a 0° elevation angle as the solvent evaporates.

As shown, for example, in FIG. 3A, the platelet magnetic or magnetizable pigment particles are oriented as described above at the elevation angle γ described herein. In other words, the elevation angle is formed by the major axis X of the plate-like magnetic or magnetizable pigment particles and the two-dimensional surface of the substrate (x20), and wherein said elevation angle γ, as measured (for example, using a conoscopic reflectometer or using a microscope such as that described herein) document below) in the cross section of the optical effect layer (OEL) and measured in the direction opposite the arrow, greater than 0° and less than 30° (0°<γ<30°) or greater than 150° and less than 180° (150°<γ< 180°), preferably greater than or equal to about 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, the elevation angle γ ranges from about 5° to about 25° (5°<γ<25°) or from about 155° to about 175° (155°<γ<175°).

For embodiments in which plate-like magnetic or magnetizable pigment particles are uniaxially oriented, as shown, for example, in FIG. 2B, the orientation of the lamellar pigment particles is defined by a lamellar vector, which is a vector parallel to the major X axis of the particle, with the lamellar vectors of adjacent lamellar magnetic or magnetizable pigment particles being substantially parallel to each other; those. only the major X axes of adjacent lamellar magnetic or magnetizable pigment particles are substantially parallel to each other (in other words, adjacent lamellar magnetic or magnetizable pigment particles have substantially the same elevation angle γ).

For embodiments in which the platelet magnetic or magnetizable pigment particles are biaxially oriented, as shown, for example, in FIG. 2C, the orientation of the lamellar pigment particles is defined by a lamellar vector that is a vector parallel to the major X axis of the particle, wherein the lamellar vectors of adjacent lamellar magnetic or magnetizable pigment particles are substantially parallel to each other, and is further defined by a second lamellar vector that represents is a vector parallel to the second Y-axis of the particle, wherein the plate vectors of adjacent plate-like magnetic or magnetizable pigment particles are substantially parallel to each other and the second plate-vectors of said adjacent plate-like magnetic or magnetizable pigment particles are substantially parallel to each other. For embodiments in which the platelet magnetic or magnetizable pigment particles are biaxially oriented, as shown, for example, in FIG. 2C, the platelet vectors of adjacent platelet magnetic or magnetizable pigment particles are substantially parallel to each other, and not only the major X axes of adjacent platelet magnetic or magnetizable pigment particles are substantially parallel to each other (in other words, adjacent platelet magnetic or magnetizable pigment particles have substantially the same elevation angle γ), but also the major Y axes of adjacent lamellar magnetic or magnetizable pigment particles are substantially parallel to each other. For embodiments in which the platelet magnetic or magnetizable pigment particles are biaxially oriented, as shown, for example, in FIG. 2C, the plate-like magnetic or magnetizable particles are substantially parallel to each other.

Suitable examples of platelet magnetic or magnetizable pigment particles described herein include, but are not limited to, pigment particles containing a magnetic metal selected from the group consisting of cobalt (Co), iron (Fe) and nickel (Ni); a magnetic alloy of iron, manganese, cobalt, nickel or a mixture of two or more of them; magnetic oxide of chromium, manganese, cobalt, iron, nickel or a mixture of two or more of them; or a mixture of two or more of them. The term magnetic in relation to metals, alloys and oxides refers to ferromagnetic or ferrimagnetic metals, alloys and oxides. Magnetic oxides of chromium, manganese, cobalt, iron, nickel, or mixtures of two or more of these may be pure or mixed oxides. Examples of magnetic oxides include, but are not limited to, iron oxides such as hematite (Fe ₂ O ₃ ), magnetite (Fe ₃ O ₄ ), chromium dioxide (CrO ₂ ), magnetic ferrites (MFe ₂ O ₄ ), magnetic spinels (MR ₂ O ₄ ) , magnetic hexaferrites

- 10 045205 (MFe ₁₂ O ₁₉ ), magnetic orthoferrites (RFeO ₃ ), magnetic garnets M ₃ R ₂ (AO ₄ ) ₃ , where M is a divalent metal, R is a trivalent metal, and A is a tetravalent metal.

Examples of platelet, magnetic, or magnetizable pigment particles described herein include, but are not limited to, pigment particles comprising a magnetic layer M made of one or more magnetic metals such as cobalt (Co), iron (Fe), or nickel (Ni); and also a magnetic alloy of iron, cobalt or nickel, wherein said magnetic or magnetizable pigment particles may be multilayer structures containing one or more additional layers. Preferably, the one or more additional layers are layers A, independently made from one or more materials selected from the group consisting of metal fluorides such as magnesium fluoride (MgF ₂ ), silicon oxide (SiO), silicon dioxide (SiO ₂ ) , titanium oxide (TiO ₂ ) and aluminum oxide (Al ₂ O ₃ ), more preferably silicon dioxide (SiO ₂ ); or layers B independently made from one or more materials selected from the group consisting of metals and metal alloys, preferably selected from the group consisting of reflective metals and reflective metal alloys, and more preferably selected from the group consisting of aluminum (Al) , chromium (Cr) and nickel (Ni), and even more preferably aluminum (Al); or a combination of one or more A layers, such as those described herein above, and one or more B layers, such as those described above herein. Typical examples of lamellar magnetic or magnetizable pigment particles that are multilayer structures described hereinabove include, but are not limited to, A/M multilayer structures, A/M/A multilayer structures, A/M/B multilayer structures, A/B/multilayer structures 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, B/A/M/B multilayer structures, B/A/M/B/A/ multilayer structures, wherein the A layers, the magnetic layers M and the B layers are selected from those described above herein.

In one embodiment, at least a portion of the preferred lamellar, magnetic, or magnetizable particles are formed by lamellar optically variable magnetic or magnetizable pigment particles. Optically variable pigments refer to a pigment having a change in brightness or a combination of a change in brightness and a change in hue. In one embodiment, at least a portion of the platelet, magnetic, or magnetizable particles are formed by particles having a metallic color, more preferably a silver color or a gold color.

In addition to the explicit protection provided by the color changing property of the optically varying magnetic or magnetizable pigment particles, which allows for easy detection, recognition and/or differentiation of an article or security document to which an ink, coating composition or coating layer containing optically varying magnetic or magnetizable pigment particles described herein from their possible counterfeiting, using the naked human senses, the optical properties of optically varying magnetic or magnetizable pigment particles can also be used as a machine-readable tool for OEL recognition. Thus, the optical properties of the optically variable magnetic or magnetizable pigment particles can simultaneously be used as a latent or semi-latent security feature in an authentication process that analyzes the optical (eg, spectral) properties of the pigment particles, thereby increasing counterfeit security.

The use of lamellar, optically variable magnetic or magnetizable pigment particles in OEL increases the value of said OEL as a security feature in security document applications since such materials are intended for security document printing and are not available for commercial use by the general public.

Preferably, the platelet, 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 of them.

Magnetic thin film interference pigment particles are known to those skilled in the art and are disclosed, for example, in US Pat. No. 4,838,648; WO 2002/073250 A2; EP 0686675 B1; WO 2003/000801 A2; US 6838166; WO 2007/131833 A1; EP 2402401 B1; WO 2019/103937 A1; WO 2020/006286 A1 and the documents referred to therein. Preferably, the magnetic thin film interference pigment particles are pigment particles having a five-layer Fabry-Perot structure and/or pigment particles having a six-layer Fabry-Perot structure and/or pigment particles having a seven-layer Fabry-Perot structure and/or pigment particles having a multilayer structure combining one or more multilayer Fabry-Perot structures.

Preferred five-layer Fabry-Perot structures consist of absorber/dielectric/reflector/dielectric/absorber multilayer structures, wherein the reflector and/or absorber is also a magnetic layer, preferably the reflector and/or absorber is a magnetic layer containing nickel, iron and/or or cobalt, and/or a magnetic alloy containing

- 11 045205 nickel, iron and/or cobalt, and/or magnetic oxide containing nickel (Ni), iron (Fe) and/or cobalt (Co).

Preferred six-layer Fabry-Perot structures consist of absorber/dielectric/reflector/magnetic material/dielectric/absorber multilayer structures.

Preferred seven-layer Fabry-Perot structures consist of absorber/dielectric/reflector/magnetic material/reflector/dielectric/absorber multilayer structures, such as those described in US 4,838,648.

Preferred pigment particles having a multilayer structure combining one or more Fabry-Perot structures are those described in WO 2019/103937 A1 and consisting of combinations of at least two Fabry-Perot structures, wherein said two Fary-Perot structures independently contain a reflective layer, a dielectric layer, and an absorbing layer, wherein each of the reflective and/or absorbent layer may independently comprise one or more magnetic materials, and/or wherein the magnetic layer is a layered material between the two structures. WO 2020/006/286 A1 and EP 3587500 A1 disclose further preferred pigment particles having a multilayer structure.

Preferably, the reflective layers described herein are independently made of one or more materials 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 made 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 made of one or more materials selected from the group consisting of metal fluorides such as magnesium fluoride (MgF ₂ ), aluminum fluoride (AlF ₃ ), cerium fluoride (CeF ₃ ), lanthanum fluoride (LaF ₃ ) , sodium aluminum fluorides (for example, NasAlF ₆ ), neodymium fluoride (NdF ₃ ), samarium fluoride (SmF ₃ ), barium fluoride (BaF ₂ ), calcium fluoride (CaF ₂ ), lithium fluoride (LiF), as well as metal oxides such such as silicon oxide (SiO), silicon dioxide (SiO ₂ ), titanium oxide (TiO ₂ ), aluminum oxide (Al ₂ O ₃ ), more preferably selected from the group consisting of magnesium fluoride (MgF ₂ ) and silicon dioxide (SiO ₂ ), and even more preferably magnesium fluoride (MgF ₂ ). Preferably, the absorbent layers are independently made of one or more materials 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), oxides of these metals, sulfides of these metals , carbides of these metals, as well as alloys of these metals, more preferably selected from the group consisting of chromium (Cr), nickel (Ni), oxides of these metals and alloys of these metals, and even more preferably selected from the group consisting of chromium (Cr ), nickel (Ni) and alloys of these metals. Preferably, the magnetic layer contains nickel (Ni), iron (Fe) and/or cobalt (Co); and/or a magnetic alloy containing nickel (Ni), iron (Fe) and/or cobalt (Co); and/or a magnetic oxide containing nickel (Ni), iron (Fe) and/or cobalt (Co). If the magnetic thin film interference pigment particles containing a seven-layer Fabry-Perot structure are preferred, it is particularly preferable that the magnetic thin film interference pigment particles contain a seven-layer Fabry-Perot absorber/dielectric/reflector/magnetic material/reflector/dielectric/absorber structure consisting of multilayer structure Cr/MgF2/Al/Ni/Al/MgF2/Cr.

The magnetic thin film interference pigment particles described herein may be multi-layer pigment particles that are considered safe for human health and the environment and are based on, for example, five-layer Fabry-Perot structures, six-layer Fabry-Perot structures and seven-layer Fabry-Perot structures. Feather, wherein said pigment particles contain one or more magnetic layers containing a magnetic alloy having an essentially nickel-free composition including from about 40 wt.% to about 90 wt.% iron, from about 10 wt.% to about 50 wt. % chromium and from about 0 wt.% to about 30 wt.% aluminum. Typical examples of multilayer pigment particles which are considered safe for human health and the environment can be found in EP 2402401 B1, the contents of which are incorporated herein by reference in their entirety.

Suitable magnetic cholesteric liquid crystal pigment particles exhibiting optically variable characteristics 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 A1, US 6582781 and US 6531221. WO 2006/063926 A1 discloses monolayers and pigment particles derived from them with increased gloss and color change properties, as well as additional special properties , such as magnetizability. The disclosed monolayers and pigment particles, which are obtained from them by grinding said monolayers, include three-dimensionally cross-linked cholesteric liquid crystal mixture and magnetic nanoparticles. In US documents

- 12 045205

6,582,781 and US 6,410,130 disclose lamellar cholesteric multilayer pigment particles that contain the sequence A1/B/A ² , where A ¹ and A ² may be identical or different from each other, and each contains at least one cholesteric layer, and B represents an intermediate layer that absorbs all or some of the light transmitted by layers A ¹ and A ² and provides magnetic properties to said intermediate layer. US 6,531,221 discloses lamellar cholesteric multilayer pigment particles that contain the sequence A/B and optionally C, where A and C are absorbent layers containing pigment particles imparting magnetic properties and B is a cholesteric layer.

Suitable interference coating pigment particles containing one or more magnetic materials include, but are not limited to, structures consisting of a support selected from the group consisting of a core coated with one or more layers, wherein at least one of the core or one or more layers has magnetic properties. For example, suitable interference coating pigment particles comprise a core made of a magnetic material such as those described herein above, wherein said core is coated with one or more layers made of one or more metal oxides, or they have a structure consisting of a core made from synthetic or natural mica, layered silicates (for example, talc, kaolin and sericite), glasses (for example, borosilicates), silicon dioxides (SiO ₂ ), aluminum oxides (Al ₂ O ₃ ), titanium oxides (TiO ₂ ), graphites and mixtures of two or more of them. Moreover, one or more additional layers, such as coloring layers, may be present.

The d ₅₀ size of the platelet, magnetic, or magnetizable pigment particles described herein is preferably from about 2 μm to about 50 μm (as measured by direct optical granulometry).

The surface of the platelet magnetic or magnetizable pigment particles described herein may be treated to protect them from any damage that may occur in the coating composition and coating layer and/or to facilitate their incorporation into said coating composition and a coating layer; Typically, corrosion inhibitors and/or wetting agents can be used.

According to one embodiment, shown for example in FIG. 3A, OELs described herein comprise one at least partially cured coating layer (310) into which are included magnetically oriented platelet magnetic or magnetizable pigment particles, wherein substantially all platelet magnetic or magnetizable pigment particles have substantially the same elevation angle γ.

According to one embodiment, shown for example in FIG. 3B-E, OELs described herein comprise two zones containing lamellar magnetic or magnetizable pigment particles, wherein substantially all lamellar magnetic or magnetizable pigment particles in one zone have substantially the same elevation angle γ and substantially all lamellar magnetic or the magnetizable pigment particles in another zone have substantially the same additional 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 or equal to about 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 range from about 5° to about 25° (5°<γ<25°) or from about 155° to about 175° (155°<y<175°) and wherein the additional 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 or equal to approximately 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 from about 5° to about 25° (5°<γ'<25°) or from about 155° to approximately 175° (155°<γ'<175°), wherein said elevation angle γ and the additional elevation angle γ' differ from each other (preferably they differ by at least 10°) and/or are not coplanar.

According to one embodiment, for OELs containing platelet magnetic or magnetizable pigment particles with an elevation angle γ and an additional elevation angle γ' that are different, the additional elevation angle γ' has the following value: γ'=180-γ, such as, for example, if γ is 20°, then γ' is 160° (in other words, the magnetic orientation patterns of the two zones are essentially symmetrical).

According to one embodiment, shown for example in FIG. 3B, OELs described herein comprise one at least partially cured coating layer (310) comprising lamellar magnetic or magnetizable pigment particles in one or more first zones (310-a) and lamellar magnetic or magnetizable pigment particles in one or more more second zones (310-b), wherein substantially all platelet magnetic or magnetizable pigment particles in one or more first zones (310-a) have substantially the same elevation angle γ and substantially all platelet magnetic or magnetizable pigment particles in one or more second zones (310-b) have substantially the same additional elevation angle γ', wherein

- 13 045205 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 or equal to approximately 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 from about 155° to about 175° (155°<γ<175°), and wherein the additional 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 or equal to about 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 from about 5° to about 25° (5°<γ'<25°) or from about 155° to about 175° (155°<γ'<175°), wherein said elevation angle γ and the additional elevation angle γ' differ from each other (preferably they differ by at least 10°) and/or are not coplanar.

According to one embodiment, shown for example in FIG. 3C-E OELs described herein comprise at least a partially cured coating layer (310) into which are included magnetically oriented platelet magnetic or magnetizable pigment particles, wherein substantially all of the platelet magnetic or magnetizable pigment particles have substantially the same elevation angle γ, and additionally contain at least a partially cured second layer (311) of the coating, which includes magnetically oriented second plate-like magnetic or magnetizable pigment particles, wherein the plate-vectors of the second plate-like magnetic or magnetizable pigment particles are located relative to the two-dimensional surface substrate (x20) in particle positions at an additional elevation angle γ', wherein the additional elevation angle γ' is more than 0° and less than 30° (0°<γ'<30°) or more than 150° and less than 180° (150°<γ '<180°), and the specified elevation angle γ and the additional elevation angle γ' differ from each other. The at least partially cured second coating layer (x11) either 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 at least partially cured coating layer (x10), or the at least partially cured second coating layer (x11) is distant from the at least partially cured coating layer (x10).

According to one embodiment, shown for example in FIG. 3C, OELs described herein comprise two at least partially cured coating layers (310 and 311). The OELs comprise: i) an at least partially cured coating layer (310) into which are included magnetically oriented platelet magnetic or magnetizable pigment particles as described herein, and ii) an at least partially cured second coating layer (311), which includes magnetically oriented second plate-like magnetic or magnetizable pigment particles, wherein said at least partially cured second coating layer (311) partially overlaps the at least partially cured coating layer (310), with substantially all of the plate-like magnetic or magnetizable particles pigment in the at least partially cured coating layer (310) have substantially the same elevation angle γ and substantially all of the second platelet magnetic or magnetizable pigment particles in the at least partially cured second coating layer (311) have substantially the same additional 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 or equal to approximately 5° or less 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 from about 155° to about 175° (155°<γ<175°), and wherein the additional 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 or equal to about 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 from about 5° to about 25° (5°<γ'<25°) or from about 155° to about 175° (155°<γ'<175°) , wherein said elevation angle γ and the additional elevation angle γ' differ from each other (preferably they differ by at least 10°) and/or are not coplanar.

According to one embodiment, shown for example in FIG. The 3D OELs described herein comprise two at least partially cured coating layers (310 and 311). The OELs comprise: i) an at least partially cured coating layer (310) into which are included magnetically oriented platelet magnetic or magnetizable pigment particles as described herein, and ii) an at least partially cured second coating layer (311), which includes magnetically oriented second plate-like magnetic or magnetizable pigment particles, wherein said at least partially cured second coating layer (311) completely covers the at least partially cured coating layer (310), with substantially all of the plate-like magnetic or magnetizable particles pigment at least

- 14 045205 partially cured coating layer (310) have substantially the same elevation angle γ and substantially all of the second plate-like magnetic or magnetizable pigment particles in the at least partially cured second coating layer (311) have substantially the same elevation angle γ', with In this case, 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 or equal to approximately 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 from about 155° to about 175° (155°<γ<175°) and wherein the additional elevation angle γ' is greater than 0° and less than 30° (0°<γ'<30°) or greater than 150° and less 180° (150°<γ'<180°), preferably greater than or equal to about 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 from about 5° to about 25° (5°<γ'<25°) or from about 155° to about 175° (155°<γ'<175°), wherein said elevation angle γ and the additional elevation angle γ' differ from each other (preferably they differ by at least 10°) and/or are not coplanar.

According to one embodiment, shown for example in FIG. 3E, OELs described herein comprise two at least partially cured coating layers (310 and 311). The OELs comprise: i) an at least partially cured coating layer (310) into which are included magnetically oriented platelet magnetic or magnetizable pigment particles as described herein, and ii) an at least partially cured second coating layer (311), which includes magnetically oriented second plate-like magnetic or magnetizable pigment particles, wherein said at least partially cured second coating layer (311) is adjacent to (FIG. 3E) or remote from (not shown), wherein substantially all of the lamellar 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 lamellar magnetic or magnetizable pigment particles in the at least partially cured second coating layer (311) have substantially the same additional 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 or equal to about 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 from about 155° to about 175° (155°<γ<175°), and 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 or equal to approximately 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 from about 5° to about 25° (5°<γ'<25°) or from about 155° to about 175° (155°<γ'<175°), wherein said elevation angle γ and the additional elevation angle γ' differ from each other (preferably they differ by at least 10°) and/or are not coplanar.

The substrate (x20) described herein is preferably selected from the group consisting of paper or other fibrous materials (including woven and non-woven fibrous materials), such as cellulose, materials containing paper; glasses, metals, ceramics, plastics and polymers, metallized plastics or polymers, composite materials and mixtures or combinations of two or more of them. Typical paper, paper-like or other fibrous materials are made from a variety of fibers, including, without limitation, manila hemp, cotton fiber, flax fiber, wood pulp and mixtures thereof. As is well known to those skilled in the art, cotton fibers and cotton/linen blends are preferred for banknotes, while wood pulp is typically used for non-banknote security documents. 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 of them. Suitable examples of plastics and polymers include polyolefins such as polyethylene (PE) and polypropylene (PP), including biaxially oriented polypropylene (BOPP), polyamides, polyesters such as poly(ethylene terephthalate) (PET), poly(1,4-butylene terephthalate) (PBT), poly(ethylene-2,6naphthoate) (PEN) and polyvinyl chloride (PVC). High velocity air ejection molded olefin fibers, such as those sold under the trade name Tyvek®, can also be used as the support. Typical examples of metallized plastics or polymers include plastics or polymer materials described above herein, on the surface of which metal is continuously or discontinuously located. 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 foregoing metals. Metallization of plastic or polymeric materials described herein above can be accomplished using the electrodeposition process.

- 15 045205 deniya, high-vacuum coating process or using the spraying process. Typical examples of composite materials include, but are not limited to, multilayer structures or laminates of paper and at least one plastic or polymeric material, such as those described herein above, as well as plastic and/or polymeric fibers embedded in a paper-like or fibrous material, such as described above in this document. Of course, the substrate may contain additional additives known to those skilled in the art, such as fillers, sizing agents, brighteners, processing aids, reinforcing agents or wet strength agents, etc. When the OELs described herein are used for decorative or cosmetic purposes, including, for example, nail varnishes, said OEL may be formed on another type of substrate, including fingernails, artificial nails, or other animal or human parts. The substrates (x20) described herein can be in the form of webs, sheets, spools of thread, reels of film, label rolls, or stacks of labels.

If one or more of the OELs described herein will be on a security document, and in order to further enhance the security and resistance against counterfeiting and unauthorized reproduction of said security document, the substrate may contain printed, coated or laser-marked or laser-perforated indicia marks, watermarks, security threads, fibers, confetti, fluorescent compounds, windows, foils, decals and combinations of two or more of these. For the same purpose, to further increase the level of security and protection against counterfeiting and illegal reproduction of security documents, the substrate may contain one or more marker substances or markers and/or machine-readable substances (for example, luminescent substances, UV/visible/IR absorbing substances, magnetic substances and their combinations).

According to one embodiment, security documents and decorative objects comprising a backing (x20) and one or more OELs described herein further comprise one or more designs, each independently having the shape of an indicia, wherein said one or more designs are present between a substrate (x20) and one or more OELs (or in other words, one or more OELs at least partially overlap one or more patterns). As used herein, the terms mark and indicia shall be understood to mean continuous and discontinuous layer(s) of distinctive markings or symbols or designs. Preferably, the indicia described herein are selected from the group consisting of codes, symbols, alphanumeric characters, designs, geometric designs (for example, circles, triangles and regular or irregular polygons), letters, words, numbers, logos, graphics images, portraits and their combinations. Examples of codes include encoded tags such as encoded alphanumeric data, 1D barcode, 2D barcode, QR code, DataMatrix, and IR readable codes. One or more of the characters described herein may be solid characters and/or raster characters.

In one embodiment, security documents and decorative objects comprising a substrate (x20) and one or more OELs described herein further comprise one or more layers of primer, wherein said one or more layers of primer are present between the substrate (x20) and one or more OEL. This may improve the quality of one or more of the OELs described herein or promote adhesion. Examples of these primer layers can be found in WO 2010/058026 A2.

For the purpose of increasing durability through resistance to staining or chemical resistance and cleanliness, and thus the service life of security documents or decorative objects containing one or more OELs described herein, or for the purpose of changing their aesthetic appearance (e.g., optical gloss), one or more protective layers can be applied on top of one or more OELs. If present, one or more protective layers are usually made of protective varnishes. Protective varnishes can be radiation-curing compositions, heat-curing compositions, or any combination thereof. Preferably, the one or more protective layers are radiation-curable compositions, more preferably UV-visible radiation-curable compositions. Protective layers are typically applied after OEL has formed.

The OELs described herein can be applied directly to a substrate (x20) on which they are to remain permanently (eg for banknote applications or label applications). Alternatively, for production purposes, OEL can also be applied to a temporary substrate from which the OEL can subsequently be removed.

Alternatively, one or more adhesive layers may be present on one or more OELs or may be present on a substrate (x20), wherein said one or more adhesive layers are located on a side of the substrate opposite to the side on which one or more OELs are applied, and/or on the same side as one or more OELs, and on top of one or more OELs. Therefore, one or more adhesive layers can be applied to one or more OEL or substrate, said one

- 16 045205 or more adhesive layers are applied after completion of the curing step. Such an object can be attached to all types of documents or other products or objects without printing or other processes involving machines and mechanisms and quite high labor costs. Alternatively, the substrate described herein, containing one or more OELs described herein, can be in the form of a transfer foil that can be applied to the document or product in a separate transfer step. For this purpose, the substrate is provided with a release coating on which one or more OELs are obtained.

The present invention provides methods for producing one or more optical effect layers (OELs) described herein on substrates (x20) with a two-dimensional surface described herein.

The methods described herein include the step of a) applying to the surface of a substrate (x20) described herein a radiation-curable coating composition comprising lamellar magnetic or magnetizable pigment particles described herein, said radiation-curable radiation, the coating composition is in a first, liquid state, which allows it to be applied as a layer (x10) of coating, and the composition is not yet at least partially cured (i.e., wet) state in which the pigment particles can move and rotate in the layer. Since the radiation-curable coating composition described herein is to be applied to the surface of a substrate (x20), the radiation-curable coating composition contains at least a binder material and magnetic or magnetizable pigment particles, which composition is in the form , which allows it to be processed on the required printing or coating equipment. Preferably, said step a) is carried out using a printing process, preferably selected from the group consisting of screen printing, rotary gravure printing, flexographic printing, gravure printing (also referred to in the art as copper plate printing, engraved steel stamp printing ), pad printing and flow coating, more preferably selected from the group consisting of screen printing, rotary gravure printing, pad printing and flexographic printing, and even more preferably screen printing, rotary gravure printing and flexographic printing.

The methods described herein further include the step of b) exposing the coating layer (x 10) to the magnetic field of a magnetic field generating device (x 30) to orient at least a portion of the platelet magnetic or magnetizable pigment particles, wherein the platelet vectors of the platelet Magnetic or magnetizable pigment particles are located relative to the two-dimensional surface of the substrate (x20) at particle positions at an elevation angle γ, wherein said 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 or equal to about 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 from about 5° to about 25° (5°<γ<25°) or from about 155° to about 175° (155°<γ<175°).

The lamellar magnetic or magnetizable pigment particle orientations and elevation angles γ described herein are obtained by exposing the lamellar magnetic or magnetizable pigment particles to the magnetic field (x30) of the magnetic field generating device described herein in one or more areas (shown). in the figures by dotted rectangles A and A'), in which the magnetic field is substantially uniform (i.e., a magnetic field that has a substantially constant magnitude and direction throughout the area(s) of interest (for uniaxial orientation); or magnetic field which is substantially limited to a plane (for biaxial orientation), wherein a substrate (x20) supporting a layer (x10) of coating is provided in said one or more regions with an angle α formed by the layer (x10) of coating and tangent to the lines of magnetic field of a device (x30) generating a magnetic field in one or more regions in which the magnetic field is substantially uniform.

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 or equal to approximately 5° and less than 30° (5° <α<30°) or greater than 150° and less than or equal to about 175° (150°<α<175°), more preferably in the range of from about 5° to about 25° (5°<α<25°) or from approximately 155° to approximately 175° (155°<α<175°).

Step b) described herein is carried out with uniaxial or biaxial orientation of at least a portion of the platelet 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 main axis is limited by the magnetic field (Fig. 2B), the implementation of biaxial orientation means that the orientation of the plate-like magnetic or magnetizable pigment particles is carried out in such a way that they two

- 17 045205 the main axes X and Y are limited (Fig. 2C). Therefore, each lamellar magnetic or magnetizable pigment particle can be considered to have a major axis in the plane of the pigment particle and an orthogonal minor axis in the plane of the pigment particle. Under the influence of a magnetic field, each of the X and Y axes of plate-like magnetic or magnetizable pigment particles is oriented. Essentially, this causes adjacent lamellar magnetic pigment particles that are located close to each other in space to be positioned substantially parallel to each other. In other words, biaxial alignment aligns the planes of lamellar magnetic or magnetizable pigment particles such that the planes of said pigment particles are oriented substantially parallel to the planes of adjacent (in all directions) lamellar magnetic or magnetizable pigment particles.

According to one embodiment, step b) is carried out with uniaxial orientation of at least a portion of the plate-like magnetic or magnetizable pigment particles described herein.

Suitable magnetic field generating devices for uniaxial orientation of plate-like magnetic or magnetizable pigment particles described herein are not limited.

According to one embodiment shown in FIG. 4A1, a suitable magnetic field generating device (430) for uniaxial orientation of at least a portion of the platelet magnetic or magnetizable pigment particles consists of a dipole bar magnet. As shown in FIG. 4A1, platelet magnetic or magnetizable pigment particles in the coating layer (410) on the substrate (420) are exposed to the magnetic field (magnetic field lines are shown by lines with arrows pointing from the north pole to the south pole) of the magnetic field generating device (430) described herein, in one or more regions (shown by dashed rectangle A) in which the magnetic field is substantially uniform, and wherein the magnetic field lines are substantially parallel to each other in the one or more regions, and wherein the substrate (420) , bearing the coating layer (410), is provided in the specified one or more areas with an angle α described herein.

According to one embodiment shown in FIG. 4A2, a suitable magnetic field generating device (430) for uniaxial orientation of at least a portion of plate-like magnetic or magnetizable pigment particles consists of an assembly containing two dipole bar magnets (M1, M2) with the same magnetic direction and an iron clamp (Y), wherein said magnetic field generating device is described in US 7,047,883. As shown in FIG. 4A2, platelet magnetic or magnetizable pigment particles in the coating layer (410) on the substrate (420) are exposed to the magnetic field (magnetic field lines are shown by lines with arrows pointing from the north pole to the south pole) of the magnetic field generating device (430) described herein, in one or more regions (shown by dashed rectangle A) in which the magnetic field is substantially uniform, and wherein the magnetic field lines are substantially parallel to each other in the one or more regions, and wherein the substrate (420) , bearing the coating layer (410), is provided in the specified one or more areas with an angle α described herein.

According to one embodiment shown in FIG. 6A-B and used in the examples below, a suitable magnetic field generating device (630) for uniaxial orientation of at least a portion of the platelet magnetic or magnetizable pigment particles consists of a rectangular assembly containing two dipole bar magnets (M1, M2) and two pole tip (P1, P2). The lamellar magnetic or magnetizable pigment particles in the coating layer (610) on the substrate (620) are exposed to the magnetic field (magnetic field lines are shown by lines with arrows pointing from the north pole to the south pole) of the magnetic field generating device (630), in one or more regions (shown by dotted rectangle A) in which the magnetic field is substantially uniform, and wherein the magnetic field lines are substantially parallel to each other in the specified area, and wherein the substrate (620) supporting the coating layer (610) is provided in specified one or more areas with an angle α described herein.

According to another embodiment, step b) is carried out with a biaxial orientation of at least a portion of the lamellar magnetic or magnetizable pigment particles. For embodiments in which the method described herein includes the step of exposing a coating layer (x10) to the magnetic field of a magnetic field generating device (x30) described herein with a biaxial orientation of at least a portion of the magnetic or magnetizable pigment particles , a layer (x 10) of coating can be exposed more than once to said magnetic field generating device. Suitable magnetic field generating devices for biaxial orientation of plate-like magnetic or magnetizable pigment particles described herein are not limited. As is known to one skilled in the art, for biaxial orientation of plate magnetic or magnetizable

- 18 045205 pigment particles require a dynamic magnetic field (i.e., a time-varying/time-dependent magnetic field) that changes its direction, causing the particles to oscillate until both major axes, the X-axis and the Y-axis, are aligned . In other words, biaxial orientation requires non-simultaneous movement of the coating layer (x10) containing lamellar magnetic or magnetizable pigment particles relative to the device generating the magnetic field.

According to one embodiment shown in FIG. 10 of WO 2018/019594, a suitable magnetic field generating device (430) for biaxial orientation of at least a portion of platelet magnetic or magnetizable pigment particles consists of a linear arrangement of at least four magnets (M1-M4) which are arranged in a staggered manner order or in a zigzag pattern. As shown in FIG. 4B1, platelet magnetic or magnetizable pigment particles in the coating layer (410) on the substrate (420) are exposed to the magnetic field (magnetic field lines are shown by lines with arrows pointing from the north pole to the south pole) of the magnetic field generating device (430), in one or more regions (shown by dashed rectangles A, A') in which the magnetic field is substantially uniform, and wherein the magnetic field lines are substantially parallel to each other in the one or more regions, and wherein the substrate (420) supporting a coating layer (410) is provided in said one or more areas with an angle α described herein. EP 2157141A1 discloses a similar suitable magnetic field generating device in FIG. 5, wherein the magnetic field generating device can be used to biaxially orient at least a portion of the platelet magnetic or magnetizable pigment particles and consists of a linear arrangement of at least three, preferably at least four, magnets that are arranged in a staggered pattern or in a zigzag pattern.

According to one embodiment shown in FIG. 4B2 and Fig. 8A-B of WO 2018/019594 A1, a suitable magnetic field generating device (430) for biaxial orientation of at least a portion of lamellar magnetic or magnetizable pigment particles consists of two dipole magnets (M1, M2) with opposite magnetic direction. As shown in FIG. 4B2, platelet magnetic or magnetizable pigment particles in the coating layer (410) on the substrate (420) are exposed to the magnetic field (magnetic field lines are shown by lines with arrows pointing from the north pole to the south pole) of the magnetic field generating device (430), in one or more regions (shown by dashed rectangles A, A') in which the magnetic field is substantially uniform, and wherein the magnetic field lines are substantially parallel to each other in the one or more regions, and wherein the substrate (420) supporting a coating layer (410) is provided in said one or more areas with an angle α described herein.

According to one embodiment shown in FIG. 4B3 and 7A-B of WO 2018/019594 A1, a suitable magnetic field generating device (430) for biaxial orientation of at least a portion of lamellar magnetic or magnetizable pigment particles consists of two dipole magnets (M1, M2) with the same magnetic direction. As shown in FIG. 4B3, platelet magnetic or magnetizable pigment particles in the coating layer (410) on the substrate (420) are exposed to the magnetic field (magnetic field lines are shown by lines with arrows pointing from the north pole to the south pole) of the magnetic field generating device (430), in one or more regions (shown by dashed rectangle A) in which the magnetic field is substantially uniform, and wherein the magnetic field lines are substantially parallel to each other in the one or more regions, and wherein the substrate (420) supporting the layer (410 ) coating is provided in said one or more areas with an angle α described herein.

According to one embodiment shown in FIG. 4B4 and fig. 3A-B of WO 2018/019594 A1, a suitable magnetic field generating device (430) for biaxial orientation of at least a portion of lamellar magnetic or magnetizable pigment particles consists of a Halbach assembly containing five dipole magnets (M1-M5). As shown in FIG. 4B4, platelet magnetic or magnetizable pigment particles in the coating layer (410) on the substrate (420) are exposed to the magnetic field (magnetic field lines are shown by lines with arrows pointing from the north pole to the south pole) of the magnetic field generating device (430), in one or more regions (shown by dashed parallelepiped A) in which the magnetic field is substantially uniform and wherein the magnetic field lines are substantially parallel to each other in said one or more regions, and wherein the substrate (420) supporting the layer (410 ) coating is provided in said one or more areas with an angle α described herein.

According to one embodiment shown in FIG. 4B5 and fig. 12A of WO 2016/083259 A1, a suitable magnetic field generating device (430) for biaxial orientation of at least a portion of lamellar magnetic or magnetizable pigment particles consists of a Halbach cylinder assembly containing four structures, each of which contains a magnetic rod (M1-M4) surrounded by an electromagnetic coil (not shown). As shown in FIG. 4B5, platelet magnetic or magnetizable pigment particles in the coating layer (410) on the substrate (420) are exposed to the magnetic field (magnetic field lines are shown by lines with arrows pointing from the north pole to the south pole) of the magnetic field generating device (430), in one or more regions (shown by dashed rectangle A) in which the magnetic field is substantially uniform, and wherein the magnetic field lines are substantially parallel to each other in the one or more regions, and wherein the substrate (420) supporting the layer (410 ) coating is provided in said one or more areas with an angle α described herein.

According to one embodiment shown in FIG. 4B6 and fig. 2A of co-pending application EP 20176506.2, a suitable magnetic field generating device (430) for biaxial orientation of at least a portion of plate-like magnetic or magnetizable pigment particles consists of an assembly of eight dipole bar magnets (M1-M8), said assembly comprising a first set containing a first dipole bar magnet (M4) and two second dipole bar magnets (M1, M6), a second set containing a first dipole bar magnet (M5) and two second dipole bar magnets (M3; M8), and a first pair of third bar dipole magnets (M2, M7). As shown in FIG. 4B6, platelet magnetic or magnetizable pigment particles in the coating layer (410) on the substrate (420) are exposed to the magnetic field (magnetic field lines are shown by lines with arrows pointing from the north pole to the south pole) of the magnetic field generating device (430), in one or more regions (shown by dashed rectangle A) in which the magnetic field is substantially uniform, and wherein the magnetic field lines are substantially parallel to each other in the one or more regions, and wherein the substrate (420) supporting the layer (410 ) coating is provided in said one or more areas with an angle α described herein.

According to one embodiment shown in FIG. 5A1-3 and used in the examples below, a suitable magnetic field generating device (530) for biaxial orientation of at least a portion of the platelet magnetic or magnetizable pigment particles consists of an assembly containing nine bar dipole magnets (M1-M9) with alternating magnetic directions north-south, which are located in a row. As shown in FIG. 5A2, platelet magnetic or magnetizable pigment particles in the coating layer (510) on the substrate (520) are exposed to the magnetic field (magnetic field lines are shown by lines with arrows pointing from the north pole to the south pole) of the magnetic field generating device (530), in one or more regions (shown by dashed parallelepiped A) in which the magnetic field is substantially uniform and wherein the magnetic field lines are substantially parallel to each other in said one or more regions, and wherein the substrate (520) supporting the layer (510 ) coating is provided in said one or more areas with an angle α described herein.

As is known to one skilled in the art, if the substrate (x20) supporting the coating layer (x10) is static or simultaneously moving with the magnetic field generating devices (i.e., moving at the same speed as the magnetic field generating device field) shown in Fig. 4B1-4B6 and fig. 5, plate-like magnetic or magnetizable pigment particles are uniaxially oriented under the influence of these devices.

During the magnetic orientation described herein of magnetic or magnetizable pigment particles, a substrate (x20) supporting a coating layer (x10) can be placed on a non-magnetic support plate (x40) that is made of one or more non-magnetic materials.

The methods described herein further include, in part concurrently with or subsequent to step b) step c) of at least partially curing a (x10) coating layer using a (x40) curing unit described herein with at least at least partially fixing the position and orientation of lamellar magnetic or magnetizable pigment particles in the coating layer (x10) to obtain at least a partially cured coating layer (x10) described herein, wherein the elevation angle γ 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 or equal to approximately 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 from about 5° to about 25° (5°<γ<25°) or from about 155° to approximately 175° (155°<γ<175°).

For embodiments in which step b) is carried out with biaxial orientation of at least a portion of the plate-like magnetic or magnetizable pigment particles described herein, step c) of at least partially curing the coating layer (x10) using a curing unit (x40), described herein is preferably carried out partially simultaneously with step b).

- 20 045205

According to one embodiment, to obtain one or more OELs such as those shown in FIG. 3B and described herein above, i.e. said OEL containing or consisting of one at least partially cured layer (x10) of coating containing lamellar magnetic or magnetizable pigment particles in one or more first zones (x10-a) and lamellar magnetic or magnetizable pigment particles in one or more second zones zones (x10-b), which includes magnetically oriented plate-like magnetic or magnetizable pigment particles with an elevation angle γ in one or more first zones (x10-a) and an additional elevation angle γ' in one or more second zones (x10- b ), while the elevation angle γ and the additional 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 or equal to approximately 5° and less than 30° (5°<γ,γ'<30°) or greater than 150° and less than or equal to approximately 175° (150°<γ,γ'<175°) , more preferably in the range of from about 5° to about 25° (5°<γ,γ'<25°) or from about 155° to about 175° (155°<γ,γ'<175°), wherein said angle the elevations γ and the elevation angle γ' are different from each other and/or are not coplanar; the method includes the following steps:

step a) applying to the surface of the substrate (x20) described herein a radiation-curable coating composition containing platelet magnetic or magnetizable pigment particles described herein;

step b) exposing the coating layer (x10) to the magnetic field of the magnetic field generating device (x30) described herein, with a substrate (x20) bearing the coating layer (x10) provided in one or more regions in which the magnetic field is substantially uniform as described herein with the angle α described herein;

c) the step of selectively curing at least partially by means of a block (x50) of selectively curing one or more first regions of the coating layer (x10) to fix at least a portion of the plate-like magnetic or magnetizable particles in their assumed positions and orientations, so that one or more the second zones of the layer (x10) of the coating remain such that they are not exposed to irradiation; wherein said step is carried out partially simultaneously with step b) or after it;

d) the step of exposing a layer (x 10) of coating to a second magnetic field of a second magnetic field generating device in one or more regions in which the second magnetic field is uniform, with the orientation of at least a portion of the lamellar magnetic or magnetizable pigment particles, wherein a substrate (x20) supporting a coating layer (x10) is provided in said one or more regions in which the magnetic field is substantially uniform with an angle α' formed by the coating layer (x10) and tangent to the second magnetic field lines in one or more areas in which the magnetic field is uniform, and 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 or equal to about 5° and less than 30° (5°<α'<30°) or greater than 150° and less than or equal to about 175° (150°<α'<175°), more preferably in the range of about 5 ° to about 25° (5°<α'<25°) or from about 155° to about 175° (155°<α'<175°);α' is different from α;

f) partially simultaneously with or subsequent to step d) of exposing the coating layer (x10) to the magnetic field of the second magnetic field generating device, step c) at least partially curing the coating layer (x10) using the curing unit (x40) described in this document.

According to one embodiment, to obtain one or more OELs such as those shown in FIG. 3C-D and described herein above, i.e. said OELs containing or consisting of: i) an at least partially cured coating layer (x10) in which magnetically oriented platelet magnetic or magnetizable pigment particles are included, and ii) an at least partially cured second coating layer (x11) in which are included magnetically oriented second lamellar magnetic or magnetizable pigment particles, wherein said at least partially cured second coating layer (x11) partially or completely overlaps at least partially cured coating layer (x10), wherein substantially all of the lamellar magnetic or magnetizable pigment particles in the at least partially cured coating layer (x10) have substantially the same elevation angle γ and substantially all of the second plate-like magnetic or magnetizable pigment particles in the at least partially cured second coating layer (x11) have substantially the same additional elevation angle γ'. The orientation of each of the second platelet pigment particles is determined by the platelet vector described herein, and the platelet vectors of the second platelet magnetic or magnetizable pigment particles are located relative to the two-dimensional surface of the substrate (x20) at particle positions at a complementary elevation angle γ'. The elevation angle γ and the additional 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 or equal to approximately 5° and less than 30° (5°<γ,γ'<30°) or

- 21 045205 greater than 150° and less than or equal to about 175° (150°<γ,γ'<175°), more preferably in the range from about 5° to about 25° (5°<γ,γ'<25°) or from about 155° to about 175° (155°<γ, γ'<175°), wherein said elevation angle γ and the additional elevation angle γ' are different from each other and/or are not coplanar, the method comprising:

step b) exposing the coating layer (x10) to the magnetic field of the magnetic field generating device (x30) described herein, with a substrate (x20) bearing the coating layer (x10) provided in one or more regions in which the magnetic field is substantially uniform as described herein, with the angle α described herein, partially simultaneously with or subsequent to step b) of step c) of at least partially curing the coating layer (x10) using a curing block (x40) described in this document;

after step c), step d) applying either partially (FIG. 3C) or completely (FIG. 3D) to the at least partially cured coating layer (x10) a second radiation-curable coating composition comprising second plate-like magnetic or magnetizable pigment particles, wherein said second radiation-curable coating composition is in a first, liquid state to form a second layer (x11) of coating, wherein said second radiation-curable coating composition is the same as the radiation-curable one the coating composition from step a) or different from it;

step e) exposing a second layer (x11) of coating to a second magnetic field of a second magnetic field generating device in one or more regions in which the second magnetic field is uniform, with the orientation of at least a portion of the second plate-like magnetic or magnetizable pigment particles, at wherein a substrate (x20) carrying a second coating layer (x11) is provided in said one or more regions with an angle α' formed by the second coating layer (x11) and tangent to the second magnetic field lines in the one or more regions in which the magnetic field is uniform, wherein said 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 or equal to approximately 5 ° and less than 30° (5°<α'<30°) or greater than 150° and less than or equal to about 175° (150°<α'<175°), more preferably in the range of about 5° to about 25° ( 5°<α'<25°) or from about 155° to about 175° (155°<α'<175°); wherein the second magnetic field generating device is the same as or different from the magnetic field generating device of step b); α' is different from α, and partly 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) using a block ( x40) curing to at least partially fix the position and orientation of the second plate-like magnetic or magnetizable pigment particles in the second coating layer (x11) to obtain an at least partially cured second coating layer (x11).

According to one embodiment, to obtain one or more OELs such as those shown in FIG. 3E and described herein above, i.e. said OELs containing or consisting of i) an at least partially cured coating layer (x10) in which magnetically oriented platelet magnetic or magnetizable pigment particles are included, and ii) an at least partially cured second coating layer (x11) in which magnetically oriented second plate-like magnetic or magnetizable pigment particles, wherein said at least partially cured second coating layer (x11) is adjacent to (FIG. 3E) or remote (not shown) from the at least partially cured coating layer (x10), wherein substantially all of the platelet magnetic or magnetizable pigment particles in the at least partially cured coating layer (x10) have substantially the same elevation angle γ and substantially all of the second platelet magnetic or magnetizable pigment particles in the at least partially cured second coating layer (x11) have essentially the same additional elevation angle γ'. The orientation of each of the second plate-like pigment particles is determined by a vector plate described herein, and the vector plates of the second plate-like magnetic or magnetizable pigment particles are located relative to the two-dimensional surface of the substrate (x20) at particle positions at a complementary elevation angle γ'. The elevation angle γ and the additional 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 or equal to about 5° and less than 30° (5°<γ,γ'<30°) or greater than 150° and less than or equal to about 175° (150°<γ,γ'<175°), more preferably in range from approximately 5° to approximately 25° (5°<γ,γ'<25°) or from approximately

- 22 045205

155° to approximately 175° (155°<γ,γ'<175°), wherein said elevation angle γ and the additional elevation angle γ' are different from each other and/or are not coplanar, the method comprising the step of:

a) applying to the surface of the substrate (x20) described herein a radiation-curable coating composition containing platelet magnetic or magnetizable pigment particles described herein;

after step c), step d) of applying a second radiation-curable coating composition comprising second plate-like magnetic or magnetizable pigment particles, said second radiation-curable coating composition being in a first, liquid state to form a second layer (x11 ) coating, wherein said second coating layer (x 11) is either adjacent to (FIG. 3E) the coating layer (x 10) or remote therefrom (not shown), and wherein said second radiation-curable coating composition is the same as or different from the radiation-curable coating composition of step a);

step e) exposing a second layer (x11) of coating to a magnetic field of a second magnetic field generating device in one or more regions in which the second magnetic field is uniform, with the orientation of at least a portion of the second plate-like magnetic or magnetizable pigment particles, wherein a substrate (x20) carrying a second coating layer (x11) is provided in said one or more regions with an angle α' formed by the second coating layer (x11) and tangent to the second magnetic field lines in one or more regions in which the magnetic field is uniform, wherein said 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 or equal to approximately 5° and less than 30° (5°<α'<30°) or greater than 150° and less than or equal to about 175° (150°<α'<175°), more preferably in the range from about 5° to about 25° (5 °<α'<25°) or from about 155° to about 175° (155°<α'<175°); wherein the second magnetic field generating device is the same as or different from the magnetic field generating device of step b); α' is different from α, and partly 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) using a block ( x40) curing to at least partially fix the position and orientation of the second plate-like magnetic or magnetizable pigment particles in the second coating layer (x11) to obtain an at least partially cured second coating layer (x11).

Suitable (x40) curing units include equipment for UV-visible curing units containing a high power light emitting diode (LED) lamp, or an arc lamp such as a medium pressure mercury arc (MPMA) lamp, or a discharge in metal vapors as a source of actinic radiation. The selective curing units (x50) described herein may contain one or more fixed or removable photomasks containing one or more voids corresponding to a pattern formed as part of the coating layer. One or more (x50) selective curing units may be addressable, such as a scanning laser beam disclosed in EP 2468423 A1, a light emitting diode (LED) array disclosed in WO 2017/021504 A1, or an LED source (x41) of actinic radiation , containing an array of individually addressable actinic radiation emitters, disclosed in the simultaneously pending patent application PCT/EP2O19/O87O72.

According to one embodiment, wherein security documents or decorative objects comprising a liner (x20) described herein, one or more OELs described herein, and one or more designs described herein, between the liner (x20) and one or more OELs, each independently having the shape of an indicia, the method described herein includes the step of applying a composition in the form of one or more designs in the form of an indicia, said step being carried out before step a) described herein. The step of applying the composition in the form of one or more patterns described herein can be carried out through a non-contact liquid microdispensing process such as flow coating, spray coating, aerosol inkjet printing, electrohydrodynamic printing and inkjet printing, or can be carried out through a printing process selected from the group, with

- 23 045205 consisting of offset printing, screen printing, rotary gravure printing, flexographic printing, gravure printing (also referred to in the art as copper plate printing, engraved steel die embossing printing).

Also described herein are printing devices 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 devices (x30) ) generating a magnetic field, and one or more curing units (x40) are located in sequential and alternating stationary locations, such that a stationary device (x30) generating a magnetic field is located after the stationary printing unit and before the stationary curing unit.

Also described herein are printing devices comprising a rotating magnetic cylinder and one or more magnetic field generating devices (x30) described herein, wherein said one or more magnetic field generating devices (x30) are mounted in annular or axial grooves of a rotating magnetic cylinder, as well as printing assemblies comprising a flatbed printing unit and one or more magnetic field generating devices (x30) described herein, wherein said one or more magnetic field generating devices (x30) are mounted in the recesses flatbed printing unit.

The rotating magnetic cylinder is meant to be used in part or in combination with a part, or is part of a printing or coating equipment, and includes one or more (x30) magnetic field generating devices described herein. In an embodiment, the rotating magnetic cylinder is part of a rotary, sheet-fed or web-fed industrial printing press that operates continuously at high print speeds.

The flatbed printing unit is meant to be used in part or in combination with a part, or it is a part of printing or coating equipment, and it includes one or more (x30) magnetic field generating devices described herein. In an embodiment, the flatbed printing unit is part of an industrial sheet-fed printing press that operates intermittently.

Printing devices comprising a rotating magnetic cylinder described herein or a flatbed printing unit described herein may include a mechanism for feeding a substrate, such as those described herein, on which is located a layer of (x 10, x 11) coating, containing plate-like magnetic or magnetizable pigment particles described herein. In an embodiment of printing devices containing a rotating magnetic cylinder described herein, the substrate is supplied by a mechanism for feeding the substrate in the form of sheets or webs. In an embodiment of printing devices containing a flatbed printing unit described herein, the substrate is supplied in the form of sheets.

Printing devices comprising a rotating magnetic cylinder described herein or a flatbed printing unit described herein may comprise a coating or printing unit for applying a radiation-curable coating composition comprising plate-like magnetic or magnetizable pigment particles described in this document, onto the substrate (x20) described in this document. In an embodiment of printing devices containing a rotating magnetic cylinder described herein, the coating or printing unit operates in accordance with a rotary continuous process. In an embodiment of printing devices comprising a flatbed printing unit described herein, the coating or printing unit operates in accordance with a linear, intermittent process.

Printing devices comprising a rotating magnetic cylinder described herein or a flatbed printing unit described herein may comprise a (x40) curing unit described herein for at least partially curing a radiation-curable coating composition, comprising plate-like magnetic or magnetizable pigment particles that have been magnetically oriented by the magnetic field generating devices (x30) described herein, thereby fixing the orientation and position of the pigment particles to produce one or more OELs described herein.

Examples

Examples and comparative examples were carried out using a UV-visible screen printing ink according to the formula given in Table 1. 1, and the first and second magnetic assemblies described hereinafter.

- 24 045205

Table 1

Epoxyacrylate oligomer (APpeh) 30.1 wt. % Trimethylolpropane triacrylate monomer (APpeh) 21.0 wt. % Tripropylene glycol diacrylate monomer (APpech) 21.5 wt. % Genorad 16 (Rahn) 1.1 wt. % Aerosil 200 (Evonik) 1.1 wt. % Speedcure TPO-L (Lambson) 2.2 wt. % Irgacure® 500 (IGM) 6.4 wt. % Genocure® EPD (Rahn) 2.2 wt. % BYK® 371 (BYK) 2.2 wt. % Tego Foam ex N (Evonik) 2.2 wt. % magnetic pigment particles (*) 10.0 wt. %

(*) 5-layer platelet magnetic pigment particles having a metallic silver color and flake shape with a dso diameter of approximately 12 microns and a thickness of approximately 1 microns, obtained from VIAVI Solutions, Santa Rosa, California.

Examples E1 to E8 of the present invention exhibited an attractive appearance when tilted around the horizontal/latitudinal axis, wherein the attractive appearance is manifested by a sharp and contrasting brightness on/off effect and consists of increasing the brightness value until the maximum brightness value is reached, and then decreasing the specified brightness over a viewing/observation angle range of approximately -45° to approximately +45°.

A device that generates a magnetic field for biaxial orientation (Fig. 5).

A magnetic assembly (530) was used to biaxially orient the pigment particles. The magnetic assembly (530) contained nine bar dipole magnets (M1-M9).

Each of the nine bar dipole magnets (M1-M9) had the following dimensions: 100 mm (Ll)xlO mm (L2)xl0 mm (L3). The device (530) generating the magnetic field was built into a non-magnetic holder made of polyoxymethylene (POM) (not shown) with the following dimensions: 250 mm x 150 mm x 12 mm. Nine dipole bar magnets (M1-M9) were made of NdFeB N40.

Nine dipole bar magnets (M1-M9) were placed in a row at a distance (dl) of approximately 10 mm from each other, with the top surfaces of the nine dipole bar magnets (ΜΙΜΟ) being placed flush. The magnetic axis of each of the nine bar dipole magnets (M1-M9) was substantially parallel to the thickness (L3) of said magnets, with the magnetic direction of two adjacent magnets (M1-M9) pointing in the opposite direction (alternating magnetization).

As shown in FIG. 5A1-A2, the magnetic field was substantially uniform and the magnetic field lines were substantially coplanar in one region A.

A device that generates a magnetic field for uniaxial orientation (Fig. 6).

A device (630) generating a magnetic field was used to uniaxially orient the pigment particles. The device (630) generating the magnetic field contained two dipole bar magnets (Ml, M2) and two pole pieces (Pl, P2).

Each of the two dipole bar magnets (Ml, M2) had the following dimensions: 40 mm (Ll)x40 mm (L2)xl0 mm (L3). Two dipole bar magnets (Ml, M2) were made of NdFeB N42.

Two dipole bar magnets (Ml, M2) were placed at a distance (dl) of approximately 40 mm from each other. The magnetic axis of each of the two bar dipole magnets (Ml, M2) was substantially parallel to the length (L1) of said magnets, and the magnetic direction of the two dipole bar magnets (Ml, M2) pointed in the same direction.

Each of the two pole pieces (Pl, P2) had the following dimensions: 60 mm (L4) x 40 mm (L5) x 3 mm (L6). The two pole pieces (Pl, P2) were made of iron (ARMCO®).

Two dipole bar magnets (Ml, M2) and two pole pieces (Pl, P2) were placed so as to form a rectangular cuboid with a centered rectangular cuboid void, said void consisting of a region A in which the magnetic field was substantially uniform, and the magnetic field lines being substantially parallel to each other, so that the distance (d2) between the two pole pieces (Pl, P2) was approximately 40 mm, i.e.

-25 045205 the distance (d2) between the two pole pieces (P1, P2) was the length (L1) of the two dipole bar magnets (M1, M2).

E1-E5 and C1-C3 (Fig. 3A, 5, 7).

For each sample, UV-visible curable screen printing ink from Table. 1 was applied to a piece of PET (BG71 Color Laser Printer & Copier OHP Film from Folex 100 micrometer thick, 45 mm x 30 mm) (520) to form a coating layer (40 mm x 25 mm) (510), this application step was carried out using laboratory screen printing apparatus using a 90T screen to form a coating layer (510) whose thickness was approximately 20 μm.

While the coating layer (510) was still in a wet and not yet at least partially cured state, the substrate (520) was placed over the center of a support plate (300 mm x 40 mm x 1 mm) made of high density polyethylene (HDPE). A carrier plate carrying the substrate (520) and the coating layer (510) was moved at a speed of approximately 10 cm/s adjacent to the magnetic field generating device (530) (as illustrated in FIG. 5) at a distance (d5) of approximately 20 mm between the surface of the magnetic field generating device (530) facing the substrate (520) and the nearest edge of the coating layer (510), and the height between said nearest edge of the coating layer (510) and the bottom surface of the magnetic field generating device (530), was half the length ( _1/2 L1) of the dipole bar magnets (M1-M9). The carrier plate carrying the substrate (520) and the coating layer (510) was simultaneously moved at an angle α formed by the coating layer (510) and tangent to the magnetic field lines of the magnetic field generating device (530) in the region A in which the magnetic field was uniform, and the specified angle α had a value of approximately 1° (E1), 5° (E2), 10° (E3), 20° (E4), 25° (E5), 30° (C1), 40° (C2 ) and 50°(C3).

At least partial curing of the coating layers (510) was ensured independently using a curing unit (540) (UV LED lamp (FireFly 395 nm, 4 W/cm ² , from Phoseon)) located above the substrate path at a distance (d4) approximately 15 mm for the center of the length (L1) of the dipole bar magnet (M1-M9), adjacent to the space between the eighth and ninth dipole magnets (M8 and M9) and adjacent to the ninth dipole magnet bar (M9) at a distance (d3) of approximately 10 mm , as illustrated in FIG. 5A1-3.

E6 (Fig. 3D, 5, 8).

UV-visible curable screen printing ink from Table. 1 was applied to a piece of PET (BG71 Color Laser Printer & Copier OHP Film from Folex 100 micrometer thick, 45 mm x 30 mm) (520) to form the first layer (510) of the coating in shape A (6 mm) (510), while This application step was carried out using a laboratory screen printing apparatus using a 90T screen to form a coating layer (510) whose thickness was approximately 20 μm.

While the coating layer (510) was still in a wet and not yet at least partially cured state, the substrate (520) was placed over the center of a support plate (300 mm x 40 mm x 1 mm) made of high density polyethylene (HDPE). A carrier plate carrying the substrate (520) and the coating layer (510) was moved at a speed of approximately 10 cm/s adjacent to the magnetic field generating device (530) (as illustrated in FIG. 5) at a distance (d5) of approximately 20 mm between the surface of the magnetic field generating device (530) facing the substrate (520) and the nearest edge of the coating layer (510), and the height between said nearest edge of the coating layer (510) and the bottom surface of the magnetic field generating device (530), was half the length ( ^1/2 L1) of bar dipole magnets (M1-M9) _. The carrier plate carrying the substrate (520) and the coating layer (510) was simultaneously moved at an angle α formed by the coating layer (510) and tangent to the magnetic field lines of the magnetic field generating device (530) in the region A in which the magnetic field was uniform, and the angle was approximately 20°.

The first layer (510) of the coating was ensured to be at least partially cured by the curing block (540) under the same conditions/positions as for E1-E5 and C1-C3.

For each sample, UV-visible curable screen printing ink from Table. 1 was applied on top of the already applied coating layer (510) to form a second coating layer (511) in the form of a T (6 mm), this application step was carried out using a laboratory screen printing device using a 90T screen to form a coating layer (511) , the thickness of which was approximately 20 μm.

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

The second layer (511) of the coating was ensured to be at least partially cured by the curing block (540) under the same conditions/positions as for E1-E5 and C1-C3.

- 26 045205

E7-E8 (Fig. 3A, 6, 9).

The UV/Vis curable screen printing ink from Table 1 was applied to a piece of PET (BG71 Color Laser Printer & Copier OHP Film from Folex 100 micrometer thick, 45mm x 30mm) (620) to form a coating layer (40 mmx 25 mm) (610), wherein this application step was carried out using a laboratory screen printing apparatus using a 90T screen to form a coating layer (610) whose thickness was approximately 20 μm.

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

A support plate carrying the substrate (620) and the coating layer (610) was placed in the center of the void of the magnetic assembly (630), as illustrated in FIG. 6 at an angle α formed by the coating layer (610) and tangent to the magnetic field lines of the magnetic field generating device (630) in region A in which the magnetic field was uniform, the angle being approximately 20°.

For sample E7, after approximately 1 s, the coating layer (610) was allowed to at least partially cure with a curing unit (640) (UV LED lamp (FireFly 395 nm, 4 W/cm ² , from Phoseon)), as illustrated in fig. 6B1.

For sample E8, after exposure to a magnetic field, the support plate supporting the substrate (620) and the coating layer (610) was moved at a distance (di) of approximately 1 cm from the magnetic assembly (630), allowing the coating layer (610) to cure under the influence of for approximately 0.5 seconds of a UV LED lamp (640) from Phoseon (FireFlex type 50x75 mm, 395 nm, 8 W/cm ² ), as illustrated in FIG. 6B2.

Correlation between angles α during the orientation step and elevation angles γ of pigment particles in a layer (x 10) of the coating.

The correlation between angles α during the method described herein above and elevation angles γ was assessed by measuring said elevation angles γ using conoscopic reflectometer measurements according to the method disclosed in WO 2019/038371 A1, and by measuring the elevation angles of a selection of five adjacent pigment particles in an SEM image (ZEISS EVO HD15, using a standard sample acquisition method by embedding in an epoxy matrix (Technicol

9461) with the following dimensions: 10 mmx10 mmx30 mm) cross-section of the coating layer (x 10). The results are presented in table. 2.

________________________________________________________________Table 2

Angle a Expected corner elevation γ Elevation angle γ, measured from using a conoscopic reflectometer Elevation angle γ measured on SEM images E1 1° 1° ΝΑ¹ ΝΑ² E2 5° 5° ΝΑ¹ ΝΑ² EZ 10° 10° 11° 10° E4 20° 20° 20° 19° E5 25° 25° ΝΑ¹ ΝΑ¹ C1 30° 30° 29° ΝΑ³ C2 40° 40° ΝΑ³ ΝΑ¹

Claims

SEM measurements were carried out using an SEM microscope (ZEISS EVO HD15, magnification x500) on a microtome section of the samples (the section plane is perpendicular to the substrate surface and the thickness of the coating layer and perpendicular to the tilt axis, as illustrated in Fig. 3). The substrates bearing the coating layer were first independently embedded in epoxy resin (Technicol 9461), which was left to dry for 24 h at room temperature, and then a microtome section was cut and polished to obtain samples with the following dimensions: 10 mm x 10 mm x 30 mm. Known values were averaged over five particles.

As illustrated in table. 2, there was an excellent correlation between the angles α and the measured elevation angles γ.

Brightness at different viewing angles 0.

The samples were placed and secured with tape on a paper backing (black or white, respectively). Assemblies carrying a coating layer (x10, x11), a PET substrate (x20) and a paper substrate were independently placed on an inclined holder in an integrating sphere (inner diameter 1 m from Dongguan Yaoke Instrument Company), as illustrated in FIG. 10. The assemblies were illuminated by a light source (bulb (30 W, 100% power) located at a distance of approximately 100 cm from the surface of the PET substrate.

The camera (Nikon D800, Nikkor 105/2.8 ED lens, shutter speed 1/200 s, aperture f/36, ISO 6400) was placed on an imaginary line between the assemblies and the light source at a distance of approximately 50 cm from the PET substrate. The images were taken with a resolution of 3680x2456 pixels (TIFF).

The holder supporting the assembly was rotated so as to observe it at viewing angles θ=50°, 40°, 30°, 20°, 10°, 0°, -5°, -10°, -15°, -20° , -25°, -30°, -35°, -40°, -45°, -50°, -55°, -60°, -65° and -70° (θ<0°, which corresponds to the upper edge assembly near the chamber; θ>0° corresponds to the lower edge of the assembly near the chamber), as illustrated in FIG. 1.

The images E1-E5 and C1-C3 thus obtained from different viewing angles are shown in Fig. 7A, and the images of E6 thus obtained from different viewing angles are shown in FIG. 8.

The brightness of E1-E5, E7-E8 and C1-C3 was assessed using Adobe Photoshop® and calculating the average brightness of a 100 pixel x 100 pixel area of each individual assembly containing a (x 10, x 11) coating layer, a (x20) PET substrate and paper backing. In fig. 7B illustrates a graph obtained by reporting the brightness of E1-E5 and C1-C3, and FIG. 9 illustrates the graphs obtained by reporting the brightness of E7-E8 at different viewing angles θ in the range from -50° to +70° (x-axis: viewing angles θ [in degrees, °]; y-axis: brightness (arbitrary units)). The brightness curves are asymmetrical due to slightly less illuminated areas of the sphere due to the presence of the plate (P).

As shown in FIG. 7A, B, layers with optical effects E1-E5 (0°<γ<30°, in particular 5°<γ<30°, 5°<γ<25°) showed an attractive effect and an easily observable increase in brightness until reaching the maximum value brightness, and then decrease the specified brightness value within viewing/observing angles from approximately -45° to approximately +45°.

E1 (1°) exhibited maximum brightness at an viewing angle θ of approximately −10°; E2 (5°) exhibited maximum brightness at an viewing angle θ of approximately -15°; E3 (10°) exhibited the maximum brightness value at an viewing angle θ of approximately -25°; E4 exhibited a maximum brightness value at an viewing angle θ of approximately -35°; and E5 exhibited a maximum brightness value at an viewing angle θ of approximately -40°.

As shown in FIG. 8, the first coating layer (510 in FIG. 5, 310 in FIG. 3D) E6 in shape A was visible at viewing angles from approximately 0° to approximately +50° with a maximum brightness value at approximately +40° viewing angle, while the second/top layer of coating (511 in FIG. 5, 311 in FIG. 3D) in a T shape was visible from -15° to approximately -65° with a maximum brightness value at a viewing angle of approximately -35°.

As shown in FIG. 9A (black substrate) and 9B (white substrate), E7-E8 exhibited easily observable increases and decreases in brightness with maximum brightness values at viewing angles θ of approximately -(20°-25°) for E7 and -(10°-15°) for E8.

CLAIM

1. A secure product comprising a substrate (x20), wherein said substrate (x20) has a two-dimensional surface and one or more optical effect layers (OEL), characterized in that said one or more optical effect layers (OEL) contain magnetically oriented lamellar magnetic or magnetizable pigment particles with a major X axis located in at least a partially cured layer (x10) of the coating, wherein the orientation of the lamellar pigment particles is determined by a plate vector, which is a vector parallel to the major X axis of the particle, wherein the platelets -vectors of adjacent lamellar magnetic or magnetizable pigment particles are substantially parallel to each other,

- 28 045205 wherein the plate-vectors of plate-like magnetic or magnetizable pigment particles are located relative to the two-dimensional surface of the substrate (x20) in positions of the particles at an elevation angle γ, and the specified 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°), such that one or more optical effect layers (OEL) exhibit an increase in brightness to achieve a maximum luminance value and a decrease in brightness over the viewing angle range of -45 to +45° of the substrate (x20).

2. The product according to claim 1, characterized in that the security product is selected from a security document or a decorative object.

3. The product according to claim 1, characterized in that at least a portion of the lamellar magnetic or magnetizable particles is formed by lamellar optically variable magnetic or magnetizable pigment particles.

4. The product according to claim 1, characterized in that at least a portion of the lamellar magnetic or magnetizable particles is formed by lamellar magnetic or magnetizable pigment particles having a metallic color, preferably a silver color or a gold color.

5. Product according to any one of claims 1 to 4, characterized in that the plate-like magnetic or magnetizable particles are substantially parallel to each other.

6. An article according to any one of claims 1 to 5, further comprising one or more indicia, said one or more indicia being present between a substrate (x20) and one or more optical effect layers (OEL).

7. An article according to any one of claims 1 to 6, characterized in that one or more optical effect layers (OEL) contain magnetically oriented platelet magnetic or magnetizable pigment particles in at least a partially cured layer (x10) of the coating and contain magnetically oriented second plate-like magnetic or magnetizable pigment particles in at least a partially cured second coating layer (x11), wherein either the at least partially cured second coating layer (x11) at least partially or completely overlaps, at least a partially cured coating layer (x10), or at least a partially cured second coating layer (x11), is adjacent to at least a partially cured coating layer (x10), or at least a partially cured second coating layer the coating layer (x11) is distant from at least the partially cured coating layer (x10), wherein the vector plates of the second plate-like magnetic or magnetizable pigment particles are located relative to the two-dimensional surface of the substrate (x20) at particle positions at an additional elevation angle γ', at least in a partially cured second layer (x11) of the coating, wherein the additional 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° ), wherein said elevation angle γ and the additional elevation angle γ' differ from each other and/or are not coplanar.

8. Product according to any one of claims 1 to 7, characterized in that said elevation angle γ is greater than or equal to approximately 5 and less than 30° (5<γ<30°) or greater than 150 and less than or equal to approximately 175° (150< γ<175°), preferably in the range from about 5 to about 25° (5<γ<25°) or from about 155 to about 175° (155<γ<175°).

9. A method for producing an optical effect layer (OEL) on a substrate (x20) with a two-dimensional surface, the method comprising the steps of:

b) exposing a layer (x 10) of coating to the magnetic field of a device (x 30) generating a magnetic field in one or more areas in which the magnetic field is substantially uniform, with the orientation of at least a portion of the lamellar magnetic or magnetizable pigment particles, at wherein a substrate (x20) bearing a layer (x10) of coating is provided in said one or more regions in which the magnetic field is substantially uniform, with an angle α formed by the layer (x10) of coating and tangent to the magnetic field lines in one or more areas in which the magnetic field is substantially uniform, the angle being 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 or subsequent to step b), the step of at least partially curing the coating layer (x10) with a curing unit (x40), at least partially fixing the position and orientation of the plate-like magnetic or magnetizable pigment particles in layer (x10) of coating to obtain at least a partially cured layer (x10) of coating, wherein the orientation of the lamellar pigment particles is determined by a plate vector, which is a vector parallel to the main X axis of the particle, wherein the plate vectors of adjacent plate magnetic or magnetizable pigment particles are substantially parallel to each other, and

- 29 045205 wherein the plate-vectors of plate-like magnetic or magnetizable pigment particles are located relative to the two-dimensional surface of the substrate (x20) in positions of the particles at an elevation angle γ, and the specified elevation angle γ is greater than 0 and less than 30° (0<γ<30°) or more than 150 and less than 180° (150<γ<180°).

10. The method of claim 9, wherein the platelet magnetic or magnetizable pigment particles have a second major Y axis and the orientation of the platelet pigment particles is further defined by a second platelet vector which is a vector parallel to the second major Y axis of the particle, and wherein step b) exposing the layer (x 10) of the coating is carried out with a biaxial orientation of at least a portion of the lamellar magnetic or magnetizable pigment particles, such that the lamellar vectors of the adjacent lamellar magnetic or magnetizable pigment particles are substantially parallel to each other and the second lamellar vectors of said adjacent lamellar magnetic or magnetizable pigment particles are substantially parallel to each other.

11. Method according to claim 10, characterized in that step e) is carried out partially simultaneously with step b).

12. Method according to any one of claims 9 to 11, characterized in that the optical effect layer (OEL) contains at least a partially cured coating layer (x10) containing lamellar magnetic or magnetizable pigment particles, and at least , partially on said at least partially cured coating layer (x10), an at least partially cured second coating layer (x11) comprising second platelet magnetic or magnetizable pigment particles, wherein the orientation of each of the second platelet pigment particles is determined by the platelet -vector, which is a vector parallel to the major axis X of the second lamellar magnetic or magnetizable pigment particles, wherein the vector laminae of adjacent second lamellar magnetic or magnetizable pigment particles are substantially parallel to each other, wherein the vector laminae of the second lamellar magnetic or magnetizable pigment particles are located relative to two-dimensional surface of the substrate (x20) in particle positions at an additional elevation angle γ', which is greater than 0 and less than 30° (0<γ'<30°) or greater than 150 and less than 180° (150<γ'<180°), and said elevation angle γ and the additional elevation angle γ' are different from each other and/or are not coplanar, the method further comprising, after step c), step d) applying at least partially or completely to at least partially cured a coating layer (x10) of a second radiation-curable coating composition comprising second plate-like magnetic or magnetizable pigment particles, said second radiation-curable coating composition being in a first, liquid state to form a second coating layer (x11), wherein said second radiation-curable coating composition is the same as or different from the radiation-curable coating composition of step a);

step e) exposing a second layer (x11) of coating to a second magnetic field of a second magnetic field generating device in one or more regions in which the second magnetic field is uniform, with the orientation of at least a portion of the second plate-like magnetic or magnetizable pigment particles, at wherein a substrate (x20) bearing a second coating layer (x11) is provided in said one or more regions in which the magnetic field is substantially uniform, with an angle α' formed by the second coating layer (x11) and tangent to the second magnetic field lines in one or more areas in which the magnetic field is uniform, the angle being greater than 0 and less than 30° (0<α'<30°) or greater than 150 and less than 180° (150<α'<180°), wherein the second the magnetic field generating device is the same as or different from the magnetic field generating device from step b), α' is different from α; And

f) partially simultaneously with or subsequent to step e) of exposing the second coating layer (x11) to a second magnetic field, the step of at least partially curing the second coating layer (x11) using a curing unit (x40) with at least partially fixing the position and orientation of the second plate-like magnetic or magnetizable pigment particles in the second coating layer (x11) to provide an at least partially cured second coating layer (x11).

13. Method according to any one of claims 9 to 11, characterized in that the optical effect layer (OEL) contains at least a partially cured coating layer (x10) containing lamellar magnetic or magnetizable pigment particles, and at least , a partially cured second layer (x11) of coating containing second platelet magnetic or magnetizable pigment particles, wherein the orientation of each of the second platelet pigment particles is defined by a platelet vector, which is a vector parallel to the major X axis of the second platelet pigment particles, wherein the platelet vectors adjacent second plate-like magnetic or magnetizable pigment particles are substantially parallel to each other, at least in part from

- 30 045205 the cured second layer (x 11) of the coating is adjacent to or distant from at least the partially cured layer (x 10) of the coating, while the vector plates of the second plate-like magnetic or magnetizable pigment particles are located relative to the two-dimensional surface of the substrate (x20 ) in particle positions at an additional elevation angle γ', at least in the partially cured second layer (x11) of the coating, wherein the additional 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°), wherein said elevation angle γ and the additional elevation angle γ' are different from each other and/or are not coplanar, wherein the method further includes, after step c), step d) of applying a second a radiation-curable coating composition comprising second plate-like magnetic or magnetizable pigment particles, wherein said second radiation-curable coating composition is in a first, liquid state to form a second coating layer (x11), wherein said radiation-curable coating composition the coating composition is the same as or different from the radiation-curable coating composition of step a), and said second coating layer (x11) is adjacent to or distant from at least the partially cured coating layer (x10) From him;

step e) exposing a second layer (x11) of coating to a second magnetic field of a second magnetic field generating device in one or more regions in which the magnetic field is uniform, with the orientation of at least a portion of the second plate-like magnetic or magnetizable pigment particles, wherein a substrate (x20) bearing a second coating layer (x11) is provided in said one or more regions in which the magnetic field is substantially uniform, with an angle α' formed by the second coating layer (x11) and tangent to the second magnetic field lines in one or more regions in which the magnetic field is substantially uniform, the angle being greater than 0 and less than 30° (0<α'<30°) or greater than 150 and less than 180° (150<α'<180°), with wherein the second magnetic field generating device is the same as or different from the magnetic field generating device from step b); α' is different from α;

14. The method according to claim 12 or 13, characterized in that the angle α' is greater than or equal to approximately 5 and less than 30° (5<α'<30°) or greater than 150 and less than or equal to approximately 175° (150<α' <175°), preferably in the range from about 5 to about 25° (5<α'<25°) or from about 155 to about 175° (155<α'<175°).

15. The method according to any one of claims 9 to 14, characterized in that the angle α is greater than or equal to approximately 5 and less than 30° (5<α<30°) or greater than 150 and less than or equal to approximately 175° (150<α< 175°), preferably in the range from about 5 to about 25° (5<α<25°) or from about 155 to about 175° (155<α<175°).

16. A substrate with an optical effect layer (OEL) obtained by the method according to any one of claims 9 to 15.

-