Magnetic assemblies and processes for producing optical effect layers containing oriented non-spherical magnetic or magnetisable pigment particles - Patents.com

Abstract

The present invention relates to the field of magnetic assemblies and processes for producing optical effect layers (OELs) comprising magnetically oriented non-spherical magnetic or magnetizable pigment particles on a substrate, and in particular to producing said OELs on security documents or articles as an anti-counterfeiting measure or for decoration purposes.

Description

FIELD OF THEINVENTION

[0001]

[01] The present invention relates to the field of protection of valuable documents and valuable or branded goods against counterfeiting and illegal copying. In particular, the present invention relates to a process for producing optical effect layers (OELs) exhibiting a visually dynamic appearance and the optical effect layers obtained thereby, as well as the use of said OELs as an anti-counterfeiting measure on documents and articles. Background of the invention

[0002]

[02] It is known in the art to produce security elements and security documents by using inks, coating compositions, coatings or layers comprising magnetic or magnetisable pigment particles, in particular non-spherical optically variable magnetic or magnetisable pigment particles.

[0003]

[03] Security features of security documents and articles can be classified as "covert" and "overt" security features. The protection offered by covert security features relies on the notion that such features are hidden from human senses and that detection usually requires specialized equipment and knowledge. "Overt" security features, on the other hand, are easily detectable by human senses alone. Such features can be visually and / or tactilely detected, yet remain difficult to produce and / or copy. However, the effectiveness of an overt security feature depends heavily on its easy recognition as a security feature, since users can only make practical security checks based on the security feature if they are aware of its existence and nature.

[0004]

[04] Coatings or layers containing oriented magnetic or magnetizable pigment particles are disclosed, for example, in U.S. Patent No. 2,570,856, U.S. Patent No. 3,676,273, U.S. Patent No. 3,791,864, U.S. Patent No. 5,630,877, and U.S. Patent No. 5,364,689. Magnetically induced images, designs, and / or patterns can be produced with magnetic or magnetizable pigment particles in a coating by locally orienting the magnetic or magnetizable pigment particles in the non-solidified coating by application of a corresponding magnetic field, followed by solidification to fix the particles in their respective positions and orientations. This results in certain optical effects, i.e. fixed magnetically induced images, designs, or patterns that are highly resistant to counterfeiting. A security element based on oriented magnetic or magnetisable pigment particles can only be produced if there is available both magnetic or magnetisable pigment particles or a corresponding ink or coating composition comprising said particles and a specific technique used to solidify said ink or composition after application of said ink or coating composition and orientation of said pigment particles in the applied ink or coating composition.

[0005]

[05] If the visual appearance of a security feature changes under changing viewing conditions, such as the viewing angle, remarkable optical effects can be achieved. One example is the so-called "rolling bar" effect, as disclosed in US Patent Application Publication No. 2005 / 0106367. The "rolling bar" effect is based on the orientation of pigment particles that reproduces a curved surface throughout the coating. The observer sees a specularly reflective area that moves away from or towards the observer depending on the tilt of the image. This effect is currently used in many security elements on banknotes, such as the "5" and "10" on the 5 and 10 euro banknotes, respectively. Other examples of dynamic optical effects that give the impression of looped bodies, such as rings, are disclosed in WO 2014 / 108403 A2 and WO 2014 / 108404 A2.

[0006]

[06] EP 2 846 932 B1 discloses an optical effect layer (OEL) as well as an apparatus and method for producing said OEL, which, when a substrate carrying the OEL is tilted, gives the optical impression of a pattern of light and dark areas that move in the same direction as the tilt.

[0007]

[07] There remains a need for magnetic assemblies and processes for producing optical effect layers (OELs) based on magnetically oriented magnetic or magnetizable pigment particles in an ink or coating composition that are reliable, easy to implement, and capable of functioning in high speed production while enabling the production of OELs that exhibit dynamic effects and are difficult to produce at scale with equipment available to counterfeiters. Summary of the Invention

[0008]

[08] An object of the present invention is therefore a magnetic assembly (x00) for producing an optical effect layer (OEL) on a substrate (x20), the magnetic assembly (x00) being configured to receive the substrate (x20) in an orientation at least partially parallel to a first plane (P), a) a first magnetic field generator (x30) comprising at least four first dipole magnets (x31) oriented with their magnetic axes substantially perpendicular to a first plane (P); Each of the first dipole magnets (x31) is aligned along at least two substantially parallel straight lines α i (i=1, 2, . . . ) and at least two substantially parallel straight lines β j (j=1, 2, . . .), and a line α i and β j forms a lattice, At least two first dipole magnets (x31) are aligned along a line α i At least two other first dipole magnets (x31) are arranged on one of the straight lines α i and disposed on another one of the Each straight line α i Above and each straight line β jAbove, the north poles of the first adjacent rod-shaped dipole magnets (x31) face in opposite directions, a first dipole magnet (x31) of the first magnetic field generating device (x30) is partially or completely embedded in a first support matrix (x32); A first magnetic field generating device (x30); b) a second magnetic field generator (x40) comprising one or more second dipole magnets (x41) oriented with their magnetic axes substantially parallel to the first plane (P) and embedded partly or completely in a second support matrix (x42); A second magnetic field generating device (x40) is disposed below the first magnetic field generating device (x30), Each straight line α i and the vector sum H of the magnetic axes of the one or more second dipole magnets (x41) are substantially non-parallel and substantially non-perpendicular to each other; A second magnetic field generating device (x40); The present invention provides a magnetic assembly (x00) comprising:

[0009]

[09] Also described herein is the use of the magnetic assembly (x00) described herein to produce an optical effect layer (OEL) on a substrate described herein.

[0010]

[0010] This specification also describes a printing apparatus having a rotating magnetic cylinder with at least one of the magnetic assemblies (x00) described in this specification, or a printing apparatus having a flatbed printing unit with at least one of the magnetic assemblies (x00) described in this specification.

[0011] Also described herein is a process for producing an optical effect layer (OEL) as described herein on a substrate (x20) as described herein, comprising: i) applying a radiation curable coating composition comprising a plurality of non-spherical magnetic or magnetisable pigment particles to a surface of a substrate (x20) in a first state so as to form a coating layer (x10); exposing the radiation curable coating composition to a magnetic field of a stationary magnetic assembly (x00) as described herein so as to orient at least a portion of the non-spherical magnetic or magnetizable pigment particles; iii) at least partially curing the radiation curable coating composition of step ii) to a second state so as to fix the non-spherical magnetic or magnetisable pigment particles in their adopted positions and orientations; The process is described below.

[0012] Also described herein are optical effect layers (OELs) produced by the processes described herein.

[0013]

[0013] Also described in this specification is a method for manufacturing a security document or decorative element or object, the method comprising the steps of: a) providing a security document or decorative element or object; and b) providing an optical effect layer (OEL) as described in this specification, in particular an optical effect layer obtained by the process described in this specification, for inclusion in the security document or decorative element or object. [Brief description of the drawings]

[0014] [Figure 1A]A first magnetic field generating device (130) comprising a first support matrix (132) and four first dipole magnets (1311-1, 1311-2, 1312-1, 1312-2), each of the four first dipole magnets (131i-j: 1311-1, 1311-2, 1312-1, 1312-2) being arranged, in particular, with their respective centers (C131) on intersections of a lattice including two substantially parallel straight lines αi (i=1,2) (α1,α2) and two substantially parallel straight lines βj (j=1,2) (β1,β2); FIG. 1 is a schematic top view of a first magnetic field generating device (130) in which a straight line αi is substantially perpendicular to a straight line βj, the magnetic axes of the four first dipole magnets (1311-1, 1311-2, 1312-1, 1312-2) are oriented so as to be substantially perpendicular to a first plane (P) (in the process described herein, so as to be substantially perpendicular to the substrate), and on each straight line αi and each straight line βj, the north poles of adjacent first rod-shaped dipole magnets (131) face in opposite directions (as indicated by dark gray (north pole) and light gray (south pole)). [Figure 1B] A first magnetic field generating device (130) comprising a first support matrix (132) and four first dipole magnets (1311-1, 1311-2, 1312-1, 1312-2), wherein each of the four first dipole magnets (131i-j: 1311-1, 1311-2, 1312-1, 1312-2) is arranged, in particular, with its respective center (C131) on an intersection of a lattice including two substantially parallel straight lines αi (i=1, 2) (α1, α2) and two substantially parallel straight lines βj (j=1, 2) (β1, β2), and the two substantially parallel straight lines βi (j=1, 2) (β1, β2) are arranged in a straight line. FIG. 1 is a schematic top view of a first magnetic field generating device (130) in which the lines αi are not substantially perpendicular to the straight lines βj, the magnetic axes of the four first dipole magnets (1311-1, 1311-2, 1312-1, 1312-2) are oriented so as to be substantially perpendicular to the first plane (P) (in the process described herein, so as to be substantially perpendicular to the substrate), and on each straight line αi and each straight line βj, the north poles of adjacent first rod-shaped dipole magnets (131) face in opposite directions (as indicated by dark gray (north pole) and light gray (south pole)). [Figure 2A]A first magnetic field generating device (230) comprising a first support matrix (232) and six first dipole magnets (231i-j: 2311-1, 2311-2, 2311-3, 2312-1, 2312-2, 2312-3), wherein each of the six first dipole magnets (231) is arranged, in particular, such that each center (C231) is located on an intersection point of a lattice including two substantially parallel straight lines αi (i=1, 2) (α1, α2) and three substantially parallel straight lines βj (j=1, 2, 3) (β1, β2, β3), the straight lines αi being substantially perpendicular to the straight lines βj, and the six first dipole magnets (23 FIG. 1 is a schematic top view of a first magnetic field generating device (230) in which the magnetic axes of the first rod-shaped dipole magnets (2311-1, 2311-2, 2311-3, 2312-1, 2312-2, 2312-3) are oriented substantially perpendicular to a first plane (P) (substantially perpendicular to the substrate in the processes described herein), and on each straight line αi and each straight line βj, the N poles of adjacent first rod-shaped dipole magnets (231) face in opposite directions (as indicated by dark gray (N pole) and light gray (S pole)), and on each straight line αi, the first dipole magnets are arranged such that the N poles alternate along the straight line αi. [Figure 2B]A first magnetic field generating device (230) comprising a first support matrix (232) and six first dipole magnets (231i-j: 2311-1, 2311-2, 2311-3, 2312-1, 2312-2, 2312-3), wherein each of the six first dipole magnets (231) is arranged, in particular, such that each center (C231) is arranged on an intersection point of a lattice including two substantially parallel straight lines αi (i=1, 2) (α1, α2) and three substantially parallel straight lines βj (j=1, 2, 3) (β1, β2, β3), the straight line αi is not substantially perpendicular to the straight line βj, and the six first dipole magnets (231i-j: 2311-1, 2311-2, 2311-3, 2312-1, 2312-2, 2312-3) are arranged, in particular, such that each center (C231) is arranged on an intersection point of a lattice including two substantially parallel straight lines αi (i=1, 2) (α1, α2) and three substantially parallel straight lines βj (j=1, 2, 3) (β1, β2, β3), the straight line αi is not substantially perpendicular to the straight line βj, and the six first dipole magnets (2 FIG. 3 is a schematic top view of a first magnetic field generating device (230) in which the magnetic axes of the first rod-shaped dipole magnets (2311-1, 2311-2, 2311-3, 2312-1, 2312-2, 2312-3) are oriented substantially perpendicular to a first plane (P) (substantially perpendicular to the substrate in the processes described herein), and the first dipole magnets are arranged such that on each line αi and on each line βj, the N poles of adjacent first rod-shaped dipole magnets (231) face in opposite directions (as indicated by dark gray (N pole) and light gray (S pole)), and on each line αi, the N poles alternate along the line αi. [Figure 3A]A first magnetic field generating device (330) comprising a first support matrix (332) and six first dipole magnets (331i-j: 3311-1, 3311-2, 3312-1, 3312-2, 3313-1, 3313-2), wherein each of the six first dipole magnets (331) is arranged, in particular, such that each center (C331) is located on an intersection point of a lattice including three substantially parallel straight lines αi (i=1, 2, 3) (α1, α2, α3) and two substantially parallel straight lines βj (j=1, 2) (β1, β2), the straight lines αi being substantially perpendicular to the straight lines βj, and the six first dipole magnets (331i-j: 3311-1, 3311-2, 3312-1, 3312-2, 3313-1, 3313-2). FIG. 1 is a schematic top view of a first magnetic field generating device (330) in which the magnetic axes of the first rod-shaped dipole magnets (3311-1, 3311-2, 3312-1, 3312-2, 3313-1, 3313-2) are oriented substantially perpendicular to a first plane (P) (substantially perpendicular to the substrate in the processes described herein), and on each straight line αi and each straight line βj, the N poles of adjacent first rod-shaped dipole magnets (331) face in opposite directions (as indicated by dark gray (N pole) and light gray (S pole)), and on each straight line βj, the first dipole magnets are arranged such that the N poles alternate along the straight line βj. [Figure 3B]A first magnetic field generating device (330) comprising a first support matrix (332) and six first dipole magnets (331i-j: 3311-1, 3311-2, 3312-1, 3312-2, 3313-1, 3313-2), wherein each of the six first dipole magnets (331) is arranged, in particular, such that each center (C331) is arranged on an intersection point of a lattice including three substantially parallel straight lines αi (i=1, 2, 3) (α1, α2, α3) and two substantially parallel straight lines βj (j=1, 2) (β1, β2), the straight lines αi are not substantially perpendicular to the straight lines βj, and the six first dipole magnets (331i-j: 3311-1, 3311-2, 3312-1, 3312-2, 3313-1, 3313-2) are ... of the six first dipole magnets (331i-j: 3311-1, 3311-2, 3312-1, 3312-2, 3313-1, 3313-2) FIG. 1 is a schematic top view of a first magnetic field generator (330) in which the magnetic axes of the first rod-shaped dipole magnets (311-1, 3311-2, 3312-1, 3312-2, 3313-1, 3313-2) are oriented substantially perpendicular to a first plane (P) (substantially perpendicular to the substrate in the processes described herein), and on each straight line αi and each straight line βj, the first dipole magnets are arranged such that the N poles of adjacent first rod-shaped dipole magnets (331) point in opposite directions (as indicated by dark gray (N pole) and light gray (S pole)), and on each straight line βj, the first dipole magnets alternate in N-S polarity along the straight line βj. [Figure 4A]A first magnetic field generating device (430) comprising a first support matrix (432) and nine first dipole magnets (431i-j: 4311-1, 4311-2, 4311-3, 4312-1, 4312-2, 4312-3, 4313-1, 4313-2, 4313-3), wherein each of the nine first dipole magnets (431) is arranged, in particular, such that each center (C431) is located on an intersection point of a lattice including three substantially parallel straight lines αi (i=1, 2, 3) (α1, α2, α3) and three substantially parallel straight lines βj (j=1, 2, 3) (β1, β2, β3), the straight lines αi being substantially perpendicular to the straight lines βj, and the nine first dipole magnets (4311-1, 4311-2, 4311-3, 4312-4, 4312-5, 4312-6, 4312-7, 4312-8, 4312-9, 4313-10, 4313-21, 4313-32, 4313-31, 4313-11, 4313-12, 4313-13, 4313-14, 4313-15, 4313-16, 4313-17, 4313-18, 4313-19, 4313-22, 4313-23, 4313-24, 4313-25, 4313-26, 4313-27, 4313-28, 4313-29, 4313-3 12-1, 4312-2, 4312-3, 4313-1, 4313-2, 4313-3) are oriented so that their magnetic axes are substantially perpendicular to a first plane (P) (so that in the processes described herein, they are substantially perpendicular to the substrate), and on each straight line αi and on each straight line βj, the N poles of adjacent first bar-shaped dipole magnets (431) face in opposite directions (as indicated by dark grey (N pole) and light grey (S pole)), and on each straight line αi, the first dipole magnets are arranged so that their N polarity alternates along the straight line αi, and on each straight line βj, the first dipole magnets are arranged so that their N polarity alternates along the straight line βj. [Figure 4B]A first magnetic field generating device (430) comprising a first support matrix (432) and nine first dipole magnets (431i-j: 4311-1, 4311-2, 4311-3, 4312-1, 4312-2, 4312-3, 4313-1, 4313-2, 4313-3), wherein each of the nine first dipole magnets (431) is arranged, in particular, such that each center (C431) is arranged on an intersection point of a lattice including three substantially parallel straight lines αi (i=1, 2, 3) (α1, α2, α3) and three substantially parallel straight lines βj (j=1, 2, 3) (β1, β2, β3), the straight line αi is not substantially perpendicular to the straight line βj, and the nine first dipole magnets (4311-1, 4311-2, 4311-3, 4312-1, 4312-2, 4312-3, 4313-1, 4313-2, 4313-3) are arranged in ... 12-1, 4312-2, 4312-3, 4313-1, 4313-2, 4313-3) are oriented so that their magnetic axes are substantially perpendicular to a first plane (P) (so that in the processes described herein, they are substantially perpendicular to the substrate), and on each straight line αi and on each straight line βj, the N poles of adjacent first bar-shaped dipole magnets (431) face in opposite directions (as indicated by dark grey (N pole) and light grey (S pole)), and on each straight line αi, the first dipole magnets are arranged so that their N polarity alternates along the straight line αi, and on each straight line βj, the first dipole magnets are arranged so that their N polarity alternates along the straight line βj. [Figure 5A]A magnetic assembly (500) for producing a comparative optical effect layer (OEL) on a substrate (520), comprising: a first magnetic field generator (530) having 100 first dipole magnets (5311,...,531100) oriented such that their magnetic axes are substantially perpendicular to the substrate (520) surface and embedded in a first support matrix (532); and a second magnetic field generator (540) having second dipole magnets (541) oriented such that their magnetic axes are substantially parallel to the substrate (520) and embedded in a second support matrix (652), wherein the 100 first dipole magnets (5311,...,531100) are each oriented such that their centers are aligned with ten parallel straight lines αi (i=1,...,10) (α1 to α10) and ten parallel straight lines βj (j=1,...,10 3 is a schematic diagram showing a magnetic assembly (500) in which the first dipole magnets (5311, ..., 531100) and the second dipole magnet (542) are arranged such that the vector sum H of the magnetic axes of each straight line αi and the second dipole magnet (541) forms an angle γ of 0°, i.e., the straight lines αi and βj are parallel to each other. [Figure 5B]A magnetic assembly (500) for producing a comparative optical effect layer (OEL) on a substrate (520), comprising: a first magnetic field generator (530) having 100 first dipole magnets (5311,...,531100) oriented such that their magnetic axes are substantially perpendicular to the substrate (520) surface and embedded in a first support matrix (532); and a second magnetic field generator (540) having second dipole magnets (541) oriented such that their magnetic axes are substantially parallel to the substrate (520) and embedded in a second support matrix (652), wherein the 100 first dipole magnets (5311,...,531100) are each oriented such that their centers are aligned with ten parallel straight lines αi (i=1,...,10) (α1 to α10) and ten parallel straight lines βj (j=1,...,10 3 is a schematic diagram showing a magnetic assembly (500) in which the first dipole magnets (5311, ..., 531100) and the second dipole magnet (542) are arranged such that the vector sum H of the magnetic axes of each straight line αi and the second dipole magnet (541) forms an angle γ of 0°, i.e., the straight lines αi and βj are parallel to each other. [Figure 5C]A magnetic assembly (500) for producing a comparative optical effect layer (OEL) on a substrate (520), comprising: a first magnetic field generator (530) having 100 first dipole magnets (5311,...,531100) oriented such that their magnetic axes are substantially perpendicular to the substrate (520) surface and embedded in a first support matrix (532); and a second magnetic field generator (540) having second dipole magnets (541) oriented such that their magnetic axes are substantially parallel to the substrate (520) and embedded in a second support matrix (652), wherein the 100 first dipole magnets (5311,...,531100) are each oriented such that their centers are aligned with ten parallel straight lines αi (i=1,...,10) (α1 to α10) and ten parallel straight lines βj (j=1,...,10 3 is a schematic diagram showing a magnetic assembly (500) in which the first dipole magnets (5311, ..., 531100) and the second dipole magnet (542) are arranged such that the vector sum H of the magnetic axes of each straight line αi and the second dipole magnet (541) forms an angle γ of 0°, i.e., the straight lines αi and βj are parallel to each other. [Figure 6A]A magnetic assembly (600) for producing an optical effect layer (OEL) on a substrate (620), comprising: a first magnetic field generator (630) having 100 first dipole magnets (6311,...,631100) oriented such that their magnetic axes are substantially perpendicular to the substrate (620) surface and embedded in a first support matrix (632); and a second magnetic field generator (640) having a second dipole magnet (641) embedded in a second support matrix (642) having its magnetic axis substantially parallel to the substrate (620), wherein each of the 100 first dipole magnets (6311,...,631100) is located, in particular, at an intersection point of a grid including ten straight lines αi (i=1,...,10) (α1 to α10) and ten straight lines βj (β1 to β10). The straight lines αi are perpendicular to the straight lines βj, and on each straight line αi (α1 to α10) and on each straight line βj (j=1, . . . , 19) (β1 to β10), the N poles of adjacent first rod-shaped dipole magnets (631) face in opposite directions, and on each straight line αi (α1 to α10) and on each straight line βj (β1 to β10), the first dipole magnets are arranged so that the N poles alternate along the straight lines αi and βj. FIG. 6 is a schematic diagram of a magnetic assembly (600) in which dipole magnets are arranged such that the first dipole magnet (6311,...,631100) and the second dipole magnet (642) form an angle γ of 45° with each straight line αi and the vector sum H of the magnetic axis of the second dipole magnet (641), i.e., the straight lines αi and the vector sum H are non-parallel and non-perpendicular to each other. [Figure 6B]A magnetic assembly (600) for producing an optical effect layer (OEL) on a substrate (620), comprising: a first magnetic field generator (630) having 100 first dipole magnets (6311,...,631100) oriented such that their magnetic axes are substantially perpendicular to the substrate (620) surface and embedded in a first support matrix (632); and a second magnetic field generator (640) having a second dipole magnet (641) embedded in a second support matrix (642) having its magnetic axis substantially parallel to the substrate (620), wherein each of the 100 first dipole magnets (6311,...,631100) is located, in particular, at an intersection point of a grid including ten straight lines αi (i=1,...,10) (α1 to α10) and ten straight lines βj (β1 to β10). The straight lines αi are perpendicular to the straight lines βj, and on each straight line αi (α1 to α10) and on each straight line βj (j=1, . . . , 19) (β1 to β10), the N poles of adjacent first rod-shaped dipole magnets (631) face in opposite directions, and on each straight line αi (α1 to α10) and on each straight line βj (β1 to β10), the first dipole magnets are arranged so that the N poles alternate along the straight lines αi and βj. FIG. 6 is a schematic diagram of a magnetic assembly (600) in which dipole magnets are arranged such that the first dipole magnet (6311,...,631100) and the second dipole magnet (642) form an angle γ of 45° with each straight line αi and the vector sum H of the magnetic axis of the second dipole magnet (641), i.e., the straight lines αi and the vector sum H are non-parallel and non-perpendicular to each other. [Figure 7A]A magnetic assembly (700) for producing an optical effect layer (OEL) on a substrate (720), comprising a first magnetic field generator (730) having 100 first dipole magnets (7311, ..., 731100) oriented with their magnetic axes substantially perpendicular to the substrate (720) surface and embedded in a first support matrix (732), and a second support matrix (732) having their magnetic axes substantially parallel to the substrate (720) and embedded in a second support matrix (732). and a second magnetic field generating device (740) having two second dipole magnets (7411, 7412) embedded in a matrix (742), wherein the 100 first dipole magnets (7311, ..., 731100) each have a center including 10 straight lines αi (i = 1, ..., 10) (α1 to α10) and 10 straight lines βj (j = 1, ..., 10) (β1 to β10). The first dipole magnets are arranged on the intersections of a lattice including the straight lines αi and βj, the straight lines αi (α1 to α10) and βj (β1 to β10) are perpendicular to each other, the N poles of adjacent first rod-shaped dipole magnets (731) face in opposite directions on each straight line αi (α1 to α10) and each straight line βj (β1 to β10), and the N poles of adjacent first rod-shaped dipole magnets (731) face in opposite directions on each straight line αi (α1 to α10) and each straight line βj (β1 to β10) alternate along the straight lines αi and βj. FIG. 1 is a schematic diagram of a magnetic assembly (700) in which a first dipole magnet (7311, ..., 731100) and a second dipole magnet (7411, 7412) are arranged such that the vector sum H of each straight line αi and the magnetic axis of the second dipole magnet (7411, 7412) forms an angle γ of 45°, i.e., each straight line αi and the vector sum H are non-parallel and non-perpendicular to each other. [Figure 8A] FIG. 8A shows photographs of OELs obtained using the devices shown in FIGS. 6 and 7A, viewed at various viewing angles from −20° to +20°. [Figure 8B-1] FIG. 8A shows photographs of OELs obtained using the devices shown in FIGS. 6 and 7A, viewed at various viewing angles from −20° to +20°. [Figure 8B-2] FIG. 8A shows photographs of OELs obtained using the devices shown in FIGS. 6 and 7A, viewed at various viewing angles from −20° to +20°. [Figure 8B-3]FIG. 8A shows photographs of OELs obtained using the devices shown in FIGS. 6 and 7A, viewed at various viewing angles from −20° to +20°. Detailed Description

[0015] definition The following definitions apply to the meanings of terms employed in this specification and recited in the claims.

[0016]

[0015] In this specification, the indefinite article "a" denotes one and more than one and does not necessarily limit its referent noun to the singular.

[0017]

[0016] In this specification, the term "about" means that the quantity or value in question may be the specified particular value or another value in its vicinity. In general, the term "about" referring to a value is intended to indicate a range of ±5% of the value. As an example, the expression "about 100" indicates a range of 100 ±5, i.e., a range of 95 to 105. In general, when the term "about" is used, it can be expected that similar results or effects according to the present invention can be obtained within a range of ±5% of the specified value.

[0018]

[0017] The terms "substantially parallel" / "substantially non-parallel" refer to a deviation from parallel alignment of 10° or less, and the terms "substantially perpendicular" / "substantially non-perpendicular" refer to a deviation from perpendicular alignment of 10° or less.

[0019]

[0018] In this specification, the term "and / or" means that both or only one of the elements it connects are present. For example, "A and / or B" is intended to mean "A only, B only, or both A and B." In the case of "A only," the term also covers the possibility that B is not present, i.e., "A only and not B."

[0020]

[0019] In this specification, the term "comprising" is intended to be non-exclusive and open-ended. Thus, for example, a solution composition containing compound A may contain compounds other than A. However, the term "comprising" also encompasses the more restrictive meanings of "consisting essentially of" and "consisting of" as a specific embodiment thereof, so that, for example, a "composition comprising A, B, and optionally C" may consist essentially of A and B, or may consist essentially of A, B, and C.

[0021]

[0020] The term "coating composition" refers to any composition capable of forming a coating as described herein, in particular an optical effect layer (OEL), on a solid substrate and which is suitably and non-exclusively applicable by a printing method. The coating composition as described herein comprises at least a plurality of non-spherical magnetic or magnetizable pigment particles and a binder.

[0022]

[0021] In this specification, the term "optical effect layer (OEL)" refers to a layer comprising at least a plurality of magnetically oriented non-spherical magnetic or magnetizable pigment particles and a binder, in which the non-spherical magnetic or magnetizable pigment particles are fixed or suspended (fixed / suspended) in a predetermined position and orientation within the binder.

[0023] In the context of this disclosure, "pigment particles" refers to particulate matter that is insoluble in either the ink or the coating composition and that imparts particular spectral properties (eg, opacity, color, or color change) to the coating composition.

[0024]

[0023] In the context of the present invention, the term "magnetic axis" refers to the unit vector that connects the north pole (indicated by "N" and / or a dark gray color) and the south pole (indicated by "S" and / or a light gray color) of a magnet and points from the south pole to the north pole (Handbook of Physics, Springer 2002, p. 463). A , the magnetic axis of the second dipole magnet is indicated by an arrow having an end corresponding to the north pole.

[0025] In the context of the present invention, the term "vector sum" refers to a vector that is the result of adding together two or more magnetic axes according to the laws of vector geometry.

[0026]

[0025] As used herein, the term "at least" defines a determined amount or more, for example, "at least one" means 1, 2, or 3, etc.

[0027]

[0026] The term "security document" refers to a document that is protected against counterfeiting or fraud by at least one security feature. Examples of security documents include, but are not limited to, currency, documents of value, identification documents, etc.

[0028] The term "security feature" refers to an overt or covert image, pattern, or graphic element that can be used to authenticate a document or article that bears it.

[0029]

[0028] Where "preferred" embodiments / features are referred to in this specification, combinations of these "preferred" embodiments / features are also considered to be disclosed, provided that such combinations are technically significant.

[0030]

[0029] The present invention provides a magnetic assembly (x00) and a process using said magnetic assembly (x00) for producing an optical effect layer (OEL) comprising a plurality of non-randomly oriented non-spherical magnetic or magnetisable pigment particles dispersed in a solidified / cured material, and the optical effect layer (OEL) obtained thereby. Due to the orientation pattern of said magnetic or magnetisable pigment particles, the optical effect layer OEL described herein gives the optical impression that not only a plurality of dark points and a plurality of light points move and / or appear and / or disappear in a diagonal direction when a substrate carrying said OEL is tilted about a vertical / longitudinal axis, but also a plurality of dark points move and / or appear and / or disappear in a diagonal direction when a substrate carrying said OEL is tilted about a horizontal / lateral axis. In other words, the optical effect layer OEL described herein gives the optical impression that a plurality of dark points and a plurality of light points move, appear and / or disappear in two directions (vertical and lateral) when a substrate carrying said OEL is tilted about two perpendicular axes, i.e. the horizontal / lateral axis and the vertical / vertical axis.

[0031]

[0030] According to the magnetic assembly (x00) described herein, an OEL can be produced on a substrate (x20) described herein, said magnetic assembly (x00) being used to produce an OEL as described herein by the orientation of non-spherical magnetic or magnetisable pigment particles. The magnetic assembly (x00) described herein is based on the interaction of at least a) a first magnetic field generating device (x30) as described herein and b) a second magnetic field generating device (x40) as described herein.

[0032]

[0031] The second magnetic field generating device (x40) is disposed below the first magnetic field generating device (x30). In other words, in the process for producing an optical effect layer (OEL) described herein, the substrate (x20) having a coating layer (x10) containing non-spherical magnetic or magnetisable pigment particles is disposed on the first magnetic field generating device (x30), which is disposed on the second magnetic field generating device (x40). The first magnetic field generating device (x30) and the second magnetic field generating device (x40) are preferably substantially centred with respect to each other. That is, the first magnetic field generating device (x30) and the second magnetic field generating device (x40) described herein are preferably stacked and arranged coaxially.

[0033]

[0032] The magnetic assembly (x00) described herein includes a first magnetic field generating device (x30) described herein, the first magnetic field generating device (x30) including four or more first dipole magnets (x31) partially or completely embedded in a first support matrix (x32) described herein. For example, see Figs. 1 to 7. A As shown in FIG. 1, each of the first dipole magnets (x31) is, in particular, x31 ) are arranged on the intersections of a grid, the grid being defined by at least two substantially parallel straight lines α i and at least two substantially parallel straight lines β j (i=1, 2, etc., j=1, 2, etc.). The lattices described herein include straight lines α that intersect with each other to form cells that are square, rectangular, or parallelogram in shape. i and β j According to one embodiment, for example, the pattern shown in FIG. A As shown in FIG. 1, each of the first dipole magnets (x31) is, in particular, x31 ) are arranged on the intersections of a grid, each of which includes a first dipole magnet (x31). According to another embodiment (not shown), each of the first dipole magnets (x31) is in particular arranged at its respective center (C x31) are positioned on lattice intersections, some of which do not include the first dipole magnet (x31).

[0034]

[0033] At least two first dipole magnets (x31), in particular the respective centers (C x31 ) is substantially parallel to the straight line α i At least two other first dipole magnets (x31), in particular the centers (C x31 ) is substantially parallel to the straight line α i In other words, each straight line α i Above there are at least two first dipole magnets (x31).

[0035]

[0034] The first dipole magnets (x31), in particular the respective centers (C x31 ) is defined as at least two substantially parallel straight lines α i and at least two substantially parallel straight lines β j A line α is arranged on the intersection of a lattice including the i is the line β j Since the first dipole magnet (x31) and the center (C x31 ) is also a straight line β j is disposed on top.

[0036] In FIG. 1A and FIG. 1B, the first magnetic field generating device (130) includes four first dipole magnets (131) embedded in a first support matrix (132). 1-1 , 131 1-2 , 131 2-1 , 131 2-2 ), and the first dipole magnet (131 1-1 , 131 1-2 , 131 2-1 , 131 2-2 ) is the distance between two substantially parallel straight lines α i (α1, α2) and two substantially parallel straight lines β jIn FIG. 2A and FIG. 2B, the first magnetic field generating device (230) is composed of six first dipole magnets (231) embedded in a first support matrix (232). 1-1 , 231 1-2 , 231 1-3 , 231 2-1 , 231 2-2 , 231 2-3 ), and the first dipole magnet (231 1-1 , 231 1-2 , 231 1-3 , 231 2-1 , 231 2-2 , 231 2-3 ) is the distance between two substantially parallel straight lines α i (α1, α2) and three substantially parallel straight lines β j In FIG. 3A and FIG. 3B, the first magnetic field generating device (330) is arranged on the intersection of a lattice including six first dipole magnets (331) embedded in a first support matrix (332). 1-1 , 331 1-2 , 331 2-1 , 331 2-2 , 331 3-1 , 331 3-2 ), and the first dipole magnet (331 1-1 , 331 1-2 , 331 2-1 , 331 2-2 , 331 3-1 , 331 3-2 ) are three substantially parallel straight lines α i (α1, α2, α3) and two substantially parallel straight lines β j In FIG. 4A and FIG. 4B, the first magnetic field generating device (430) is composed of nine first dipole magnets (431) embedded in a first support matrix (432). 1-1 , 431 1-2 , 431 1-3 , 431 2-1 , 431 2-2 , 431 2-3 , 431 3-1 , 431 3-2 , 431 3-3), and the first dipole magnet (431 1-1 , 431 1-2 , 431 1-3 , 431 2-1 , 431 2-2 , 431 2-3 , 431 3-1 , 431 3-2 , 431 3-3 ) are three substantially parallel straight lines α i (α1, α2, α3) and three substantially parallel straight lines β j It is located at the intersection of the lattice including (β1, β2, β3).

[0037]

[0036] A substantially parallel straight line α i are substantially parallel to each other, and substantially parallel straight lines β j are substantially parallel to each other. For example, in FIGS. 1A, 2A, 3A, 4A, 5A to 5B, 6A, and 7 A According to one embodiment shown in i is the straight line β j That is, the straight line α i and the line β j The angle formed between the straight line α is 90°, thus forming a lattice including cells that are square or rectangular in shape. i is the straight line β j That is, the line α i and the line β j The angle formed between is not 90°, so it forms a lattice containing cells that are parallelograms in shape.

[0038]

[0037] According to one embodiment, for example as shown in Figs. 1A and 1B, at least four first dipole magnets (x31) are included in the first magnetic field generating device (x30), and each of the first dipole magnets (x31) is arranged to have a center (C x31 ) are at least two substantially parallel straight lines α i (α1, α2) and at least two substantially parallel straight lines β j It is placed at the intersection of (β1, β2) and the line αi are substantially parallel to each other, and a straight line β j are substantially parallel to each other, and a substantially parallel straight line α i and β j is a lattice (i.e., two substantially parallel straight lines α i (α1, α2) and two substantially parallel straight lines β j At least two first dipole magnets (x31), in particular the centers (C x31 ) is the straight line α i At least two other first dipole magnets (x31) are arranged on one of the straight lines α i The other one (α2) of the two is disposed on the other one (α3).

[0039] According to another embodiment, for example as shown in FIG. 2A and FIG. 2B, at least six first dipole magnets (x31) are included in the first magnetic field generating device (x30), and each of the first dipole magnets (x31) is arranged to have a center (C x31 ) are at least two substantially parallel straight lines α i (α1, α2) and at least three substantially parallel straight lines β j It is placed at the intersection of (β1, β2, β3) and a straight line α i and β j is a lattice (i.e., two substantially parallel straight lines α i (α1, α2) and three substantially parallel straight lines β j At least three dipole magnets (x31), in particular the centers (C x31 ) is the straight line α i At least three other first dipole magnets (x31) are arranged on one of the straight lines α i The other one (α2) of the two is disposed on the other one (α3).

[0040] According to another embodiment, for example as shown in FIG. 3A and FIG. 3B, at least six first dipole magnets (x31) are included in the first magnetic field generating device (x30), and each of the first dipole magnets (x31) is arranged to have a center (C x31) are at least three substantially parallel straight lines α i (α1, α2, α3) and at least two substantially parallel straight lines β j It is placed at the intersection of (β1, β2) and the line α i and β j is a lattice (i.e., three substantially parallel straight lines α i (α1, α2, α3) and two substantially parallel straight lines β j At least two first dipole magnets (x31), in particular the centers (C x31 ) is the straight line α i At least two other first dipole magnets (x31) are arranged on one of the straight lines α i and at least two other first dipole magnets (x31) are arranged on the straight line α i The other one (α3) is disposed on the other one (α4).

[0041] According to another embodiment, for example as shown in FIG. 4A and FIG. 4B, at least nine first dipole magnets (x31) are included in the first magnetic field generating device (x30), and each of the first dipole magnets (x31) is arranged to have a center (C x31 ) are at least three substantially parallel straight lines α i (α1, α2, α3) and at least three substantially parallel straight lines β j It is placed at the intersection of (β1, β2, β3) and a straight line α i and β j is a lattice (i.e., three substantially parallel straight lines α i (α1, α2, α3) and three substantially parallel straight lines β j At least three first dipole magnets (x31), in particular the centers (C x31 ) is the straight line α i At least three other first dipole magnets (x31) are arranged on one of the straight lines α i At least three other first dipole magnets (x31) are arranged on the straight line α iThe other one (α3) is disposed on the other one (α4).

[0042]

[0041] The lattice has three or more substantially parallel straight lines α i If it contains, the adjacent straight line α i 3A to 3B and 4A to 4B, the distances between adjacent straight lines α i The distances d1 and d2 between (ie, the distance d1 between α1 and α2 and the distance d2 between α2 and α3) may be the same value or different values.

[0043]

[0042] The lattice has three or more substantially parallel straight lines β j If it contains, the adjacent straight line β j 2A to 2B and 4A to 4B, the distances between adjacent straight lines β j The distances e1 and e2 between (ie, the distance e1 between β1 and β2 and the distance e2 between β2 and β3) may be the same value or different values.

[0044]

[0043] Two substantially parallel straight lines α i The distance between the two substantially parallel straight lines β j The distances between them may be the same or different.

[0045]

[0044] Each parallel straight line α i and / or each parallel straight line β j In the above, the first dipole magnets (x31) described herein may be adjacent or spaced apart from one another (i.e., not adjacent). In embodiments where the first dipole magnets (x31) are spaced apart, each first dipole magnet is separated from its respective neighboring magnet by a gap or distance greater than 0, preferably a gap or distance between about 0.1 mm and 10 mm, and more preferably a gap or distance between about 0.2 mm and 6 mm.

[0046]

[0045] All of the first dipole magnets (x31) of the first magnetic field generating device (x30) described in this specification are oriented so that their magnetic axes are substantially perpendicular to the first plane (P) (i.e., when the magnetic assembly (x00) is used in the process described in this specification, their magnetic axes are oriented so that they are substantially perpendicular to the substrate (x20) surface).

[0047] For example, as shown in FIGS. 1A and 1B, each straight line α i Above and each straight line β j In the above, the north poles of the adjacent first rod-shaped dipole magnets (x31) face in opposite directions. In other words, each straight line α i Above and each straight line β j In the above, the N pole of each first rod-shaped dipole magnet (x31) faces in the opposite direction to the N pole of each adjacent magnet. In FIG. 1A and FIG. 1B, the first magnetic field generating device (x30) is specifically arranged such that the center (C x31 ) are two substantially parallel straight lines α i (α1, α2) and two substantially parallel straight lines β j The four first dipole magnets (x31) are arranged on the intersections of the lattice including (β1, β2), and the straight line α i (α1, α2) is the line β j (β1, β2) is substantially perpendicular (see FIG. 1A) or j The four first dipole magnets (x31) are oriented so that the N poles of adjacent first bar-shaped dipole magnets (x31) face in opposite directions along the straight lines α1 and α2 and the straight lines β1 and β2, and so that the magnetic axis is substantially perpendicular to the first plane (P) (i.e., substantially perpendicular to the surface of the substrate (x20)). The first dipole magnets (131 1-1 , 131 1-2 ) is disposed on the first straight line α1, and the first dipole magnet (131 2-1 , 131 2-2 The first dipole magnet (131) is disposed on the second straight line α2. 1-1) is oriented with its south pole facing the substrate surface during the process to produce the optical effect layer (OEL) described herein, and the second first dipole magnet (131 1-2 The north pole of the first dipole magnet (131) faces the front surface of the substrate. 2-1 ) has its N pole facing the front surface of the substrate, and the second first dipole magnet (131 2-2 ) has its south pole facing the surface of the substrate.

[0048]

[0047] The first magnetic field generating device (x30) is aligned along a line α i and / or line β j In the embodiment with three or more first dipole magnets (x31) on the top, each first bar-shaped dipole magnet (x31) has its north pole facing in the opposite direction to the north pole of each adjacent magnet. In other words, the first dipole magnets (x31) are arranged such that their respective north and south polarities are aligned along a straight line α i and line β j , that is, along the straight line α i and line β j The SN magnetic fields are arranged in such a way that their directions along the

[0049] For example, as shown in FIGS. 2A and 2B, each straight line α i Above and each straight line β j In the above, the north poles of the first adjacent rod-shaped dipole magnets (x31) face in opposite directions, and each straight line α i In the above, the NS polarity is the line α i In FIG. 2A and FIG. 2B, the first magnetic field generating devices (x30) are arranged so as to alternate along the center (C x31 ) are two substantially parallel straight lines α i (α1, α2) and three substantially parallel straight lines β j Six first dipole magnets (x31) are arranged on the intersections of (β1, β2, β3), and a straight line α i (α1, α2) is the line β j (β1, β2, β3) are substantially perpendicular (see FIG. 2A) or a straight line β jThe magnetic axes of the six first dipole magnets (x31) are oriented so as to be substantially perpendicular to the first plane (P) (i.e., substantially perpendicular to the surface of the substrate (x20)). The first dipole magnets (231 1-1 , 231 1-2 , 231 1-3 ) is disposed on the first straight line α1, and the first dipole magnet (231 2-1 , 231 2-2 , 231 2-3 The first dipole magnet (231) is disposed on the second straight line α2. 1-1 ) is oriented with its south pole facing the substrate surface during the process to produce the optical effect layer (OEL) described herein, and the second first dipole magnet (231 1-2 ) has its N pole facing the front surface of the substrate, and the third first dipole magnet (231 1-3 The first dipole magnet (231) has its south pole facing the front surface of the substrate. 2-1 ) has its N pole facing the front surface of the substrate, and the second first dipole magnet (231 2-2 ) has its south pole facing the front surface of the substrate, and the third first dipole magnet (231 2-3 The N pole of the first dipole magnet (x31) shown in FIG. 2A and FIG. 2B is a straight line α i (α1, α2) and three straight lines β j (β1, β2, β3), i.e., along the straight line α i (α1, α2) and line β j The SN magnetic fields along (β1, β2, β3) are arranged in opposite directions.

[0050] For example, as shown in FIG. 3A and FIG. 3B, each straight line α i Above and each straight line β j In the above, the north poles of the first adjacent rod-shaped dipole magnets (x31) face in opposite directions, and each straight line β j In the above, the NS polarity is the line β jIn FIG. 3A and FIG. 3B, the first magnetic field generating devices (x30) are arranged so as to alternate along the center (C x31 ) are three substantially parallel straight lines α i (α1, α2, α3) and two substantially parallel straight lines β j Six first dipole magnets (x31) are arranged on the intersections of (β1, β2), and a straight line α i (α1, α2, α3) is the line β j (β1, β2) (see Figure 3A) or the line β j (β1, β2) (see FIG. 3B). The magnetic axes of the six first dipole magnets (x31) are oriented substantially perpendicular to the first plane (P) (i.e., substantially perpendicular to the surface of the substrate (x20)). The first dipole magnets (331 1-1 , 331 1-2 ) is disposed on the first straight line α1, and the first dipole magnet (331 2-1 , 331 2-2 ) is disposed on the second straight line α2, and the first dipole magnet (331 3-1 , 331 3-2 The first dipole magnet (331) is disposed on the third straight line α3. 1-1 ) is oriented with its south pole facing the substrate surface during the process to produce the optical effect layer (OEL) described herein, and the second first dipole magnet (331 1-2 The north pole of the first dipole magnet (331) faces the front surface of the substrate. 2-1 ) has its N pole facing the front surface of the substrate, and the second first dipole magnet (331 2-2 The first dipole magnet (331) has its south pole facing the front surface of the substrate. 3-1 ) has its south pole facing the front surface of the substrate, and the second first dipole magnet (331 3-2 The N pole of the first dipole magnet (x31) shown in FIG. 3A and FIG. 3B is arranged such that the N pole faces the substrate surface. i (α1, α2, α3) and two straight lines β j (β1, β2), i.e., along the straight line αi (α1, α2) and line β j The SN magnetic fields along (β1, β2) are arranged to be opposite each other.

[0051] For example, as shown in FIGS. 4A and 4B, each straight line α i Above and each straight line β j In the above, the north poles of the first adjacent rod-shaped dipole magnets (x31) face in opposite directions, and each straight line α i Above and each straight line β j In the above, the NS polarity is the line α i and β j In FIG. 4A and FIG. 4B, the first magnetic field generating devices (x30) are arranged so as to alternate along the center (C x31 ) are three substantially parallel straight lines α i (α1, α2, α3) and three substantially parallel straight lines β j The nine first dipole magnets (x31) are arranged on the intersections of (β1, β2, β3), and the straight line α i (α1, α2, α3) is the line β j (β1, β2, β3) are substantially perpendicular (see FIG. 4A) or a straight line β j The magnetic axes of the six first dipole magnets (x31) are oriented so as to be substantially perpendicular to the first plane (P) (i.e., substantially perpendicular to the surface of the substrate (x20)). The first dipole magnets (331 1-1 , 331 1-2 , 331 1-3 ) is disposed on the first straight line α1, and the first dipole magnet (331 2-1 , 331 2-2 , 331 2-3 ) is disposed on the second straight line α2, and the first dipole magnet (331 3-1 , 331 3-2 , 331 3-3 The first dipole magnet (431) is disposed on the third straight line α3. 1-1) is oriented with its south pole facing the substrate surface during the process to produce the optical effect layer (OEL) described herein, and the second first dipole magnet (431 1-2 ) has its N pole facing the front surface of the substrate, and the third first dipole magnet (431 1-3 The first dipole magnet (431) has its south pole facing the front surface of the substrate. 2-1 ) has its N pole facing the front surface of the substrate, and the second first dipole magnet (431 2-2 ) has its south pole facing the front surface of the substrate, and the third first dipole magnet (431 2-3 The north pole of the first dipole magnet (431) faces the front surface of the substrate. 3-1 ) is oriented with its south pole facing the substrate surface during the process to produce the optical effect layer (OEL) described herein, and the second first dipole magnet (431 3-2 ) has its N pole facing the front surface of the substrate, and the third first dipole magnet (431 3-3 The first dipole magnet (x31) shown in FIG. 4A and FIG. 4B has three straight lines α i (α1, α2, α3) and three straight lines β j (β1, β2, β3), i.e., along the straight line α i (α1, α2) and line β j The SN magnetic fields along (β1, β2) are arranged to be opposite each other.

[0052]

[0051] The first dipole magnets (x31) of the first magnetic field generating device (x30) described in this specification may be of the same shape, may be of the same dimensions, and may be made of the same material.

[0053]

[0052] The magnetic assembly (x00) comprises a second magnetic field generating device (x40) as described herein having one or more second dipole magnets (x41) oriented with their magnetic axes substantially parallel to the first plane (P) (i.e., in the processes described herein, substantially parallel to the substrate) and embedded in part or in whole in a second support matrix (x42) as described herein.

[0054] According to one embodiment, the second magnetic field generator (x40) comprises one second dipole magnet (x41). According to another embodiment, the second magnetic field generator (x40) comprises two or more second dipole magnets (x41) each oriented with their magnetic axis substantially parallel to the first plane (P) (substantially parallel to the substrate in the process described herein). In the case of the embodiment in which the second magnetic field generator (x40) comprises two or more second dipole magnets (x41) as described herein, it is preferred that said two second dipole magnets are arranged one above the other, and that said two or more second dipole magnets (x41) are preferably centered with respect to each other. That is to say, it is even more preferred that the two or more second dipole magnets (x41) herein are stacked and arranged coaxially. In the embodiment in which the second magnetic field generating device (x40) comprises two or more second dipole magnets (x41) as described herein, the two or more second dipole magnets may have their north poles facing in the same direction or may have their north poles facing in different directions (e.g., FIG. 7 A (See FIG. 7). In an embodiment in which the second magnetic field generator (x40) includes two or more second dipole magnets (x41) whose N poles face in the same direction, the two or more second dipole magnets (x41) may be arranged overlapping each other, side by side, or spaced apart, but are preferably in direct contact with each other. In an embodiment in which the second magnetic field generator (x40) includes two or more second dipole magnets (x41) whose N poles face in different directions, the two or more second dipole magnets (x41) are preferably arranged overlapping each other, and are preferably in direct contact with each other. For example, see FIG. 7. AAccording to one embodiment shown in, the second magnetic field generator (x40) comprises two second dipole magnets (x41) as described herein, each of which is oriented with its magnetic axis substantially parallel to the first plane (P) and with its N pole pointing in different directions, the two second dipole magnets being disposed one above the other, the two or more second dipole magnets (x41) being preferably centered and in direct contact with each other. In the case of an embodiment in which the second magnetic field generator (x40) comprises two or more second dipole magnets (x41) as described herein, the two second dipole magnets may be of the same shape, have the same dimensions and be made of the same material or may be different.

[0055]

[0054] The second magnetic field generating device (x40) described in this specification has a vector sum H of the magnetic axes of one or more second dipole magnets (x41).

[0056]

[0055] Each straight line α i and the vector sum H of the magnetic axes of one or more second dipole magnets (x41) of the second magnetic field generating device (x40) are substantially non-parallel and substantially non-perpendicular to each other. i and a vector sum H of the magnetic axes of the one or more second dipole magnets (x41) form an angle γ in the range of approximately 10° to approximately 80°, in the range of approximately 100° to approximately 170°, in the range of approximately 190° to approximately 260°, or in the range of approximately 280° to approximately 350°.

[0057]

[0056] In an embodiment in which the second magnetic field generating device (x40) comprises one second dipole magnet (x41), each straight line α i The vector sum H of the magnetic axes of the second dipole magnet (x41) constituting the second magnetic field generating device (x40) is substantially parallel to the surface of the substrate (x20) and is twisted with respect to each other. i The vector sum H of the magnetic axes of the first dipole magnet (x41) and the second dipole magnet (x42) are substantially non-parallel and substantially non-perpendicular to each other.

[0058]

[0057] In an embodiment in which the second magnetic field generating device (x40) comprises two or more second dipole magnets (x41), each straight line α i The vector sum H of one or more second dipole magnets (x41) constituting the second magnetic field generating device (x40) is substantially parallel to the surface of the substrate (x20) and is twisted with respect to each other. In these embodiments, each straight line α i And the vector sum H of the magnetic axes of the two or more second dipole magnets (x41) are substantially non-parallel and substantially non-perpendicular to each other.

[0059]

[0058] Each straight line α i The vector sum H of the first magnetic field generating device (x40) is substantially parallel to the surface of the substrate (x20) and is twisted with respect to each other (FIGS. 6A and 7). A As shown in FIG. 1, the straight lines α are substantially non-parallel and substantially non-perpendicular to each other, with the angle between them being denoted by γ. i The vector sum H of the magnetic axes of the first dipole magnet (x41) and the second dipole magnet (x42) are substantially non-parallel and substantially non-perpendicular to each other and preferably forms an angle γ in the range of approximately 20° to approximately 70°, in the range of approximately 110° to approximately 160°, in the range of approximately 200° to approximately 250°, in the range of approximately 290° to approximately 340°, and more preferably in the range of approximately 30° to approximately 70°, in the range of approximately 120° to approximately 150°, in the range of approximately 210° to approximately 240°, or in the range of approximately 300° to approximately 330°.

[0060]

[0059] The first dipole magnet (x31) of the first magnetic field generator (x30) and the one or more second dipole magnets (x41) of the second magnetic field generator (x40) are preferably independently made of a high coercivity material (also called a ferromagnetic material). A suitable high coercivity material has a maximum energy product (BH) of max is at least 20 kJ / m 3 , preferably at least 50 kJ / m 3 , more preferably at least 100 kJ / m 3 , more preferably at least 200 kJ / m 3These include Alnico, such as Alnico 5 (R1-1-1), Alnico 5DG (R1-1-2), Alnico 5-7 (R1-1-3), Alnico 6 (R1-1-4), Alnico 8 (R1-1-5), Alnico 8HC (R1-1-7), and Alnico 9 (R1-1-6), and the materials of the formula MFe 12 O 19 Hexaferrite (e.g., strontium hexaferrite (SrO * 6Fe2O3) or barium hexaferrite (BaO * 6Fe2O3), hard ferrites of formula MFe2O4 (e.g., cobalt ferrite (CoFe2O4) or magnetite (Fe3O4)) (where M is a divalent metal ion), ceramic 8 (SI-1-5), one or more sintered or polymer-bonded magnetic materials selected from the group consisting of RECo5 (RE=Sm or Pr), RE2TM 17 (RE=Sm, TM=Fe, Cu, Co, Zr, Hf), RE2TM 14 Preferably, the high coercivity material of the dipole magnet is made of a material selected from the group consisting of rare earth magnetic materials, more preferably Nd2Fe, anisotropic alloys of Fe, Cr, Co, PtCo, MnAlC, RE Cobalt 5 / 16, and RE Cobalt 14. The high coercivity material of the dipole magnet is preferably made of a material selected from the group consisting of rare earth magnetic materials, more preferably Nd2Fe 14 Preferably, the metal oxide is selected from the group consisting of B and SmCo5. Particularly preferred is strontium hexaferrite (SrFe 12 O 19 ) or neodymium / iron / boron (Nd2Fe 14 B) An easily processable permanent magnet composite material that contains a permanent magnet filler, such as a powder, in a plastic or rubber matrix.

[0061]

[0060] The distance (h1) between the top surface of the first magnetic field generator (x30) and the bottom surface of the substrate (x20) facing the first magnetic field generator (x30) is preferably about 0.5 mm to about 10 mm, more preferably about 0.5 mm to about 7 mm, and even more preferably about 1 mm to 7 mm. The distance (h2) between the bottom surface of the first magnetic field generator (x30) described herein and the top surface of the second magnetic field generator (x40) described herein is preferably about 0 to about 10 mm, more preferably about 0 to about 5 mm, and even more preferably 0.

[0062]

[0061] The first support matrix (x32) of the first magnetic field generator (x30) and the second support matrix (x42) of the second magnetic field generator (x40) described herein may independently be a disk or a regular polygon (with or without rounded corners) or a non-regular polygon (with or without rounded corners). The first support matrix (x32) of the first magnetic field generator (x30) and the second support matrix (x42) of the second magnetic field generator (x40) described herein independently are composed of one or more non-magnetic materials. The non-magnetic materials are preferably selected from the group consisting of non-magnetic metals, industrial plastics, and polymers. Non-magnetic metals include, but are not limited to, aluminum, aluminum alloys, brass (an alloy of copper and zinc), titanium, titanium alloys, and austenitic steel (i.e., non-magnetic steel). Industrial plastics and polymers include, but are not limited to, polyaryletherketone (PAEK) and its derivatives polyetheretherketone (PEEK), polyetherketoneketone (PEKK), polyetheretherketoneketone (PEEKK), and polyetherketoneetherketoneketone (PEKEKK), polyacetal, polyamide, polyester, polyether, copolyetherester, polyimide, polyetherimide, high density polyethylene (HDPE), ultra-high molecular weight polyethylene (UHMWPE), polybutylene terephthalate (PBT), polypropylene, acrylonitrile butadiene styrene (ABS) copolymer, fluorinated and perfluorinated polyethylene, polystyrene, polycarbonate, polyphenylene sulfide (PPS), and liquid crystal polymers. Preferred materials are PEEK (polyetheretherketone), POM (polyoxymethylene), PTFE (polytetrafluoroethylene), Nylon® (polyamide), and PPS.

[0063]

[0062] The magnetic assembly (x00) described herein may further comprise a magnetized plate with one or more surface reliefs, engravings and / or cutouts representing one or more indicia, said magnetized plate being disposed on a first magnetic field generator (x30). In other words, in the process for producing an optical effect layer (OEL) described herein, a substrate (x20) having a coating layer (x10) containing non-spherical magnetic or magnetizable pigment particles is disposed on said magnetized plate which is disposed on a first magnetic field generator (x30), said first magnetic field generator (x30) being disposed on a second magnetic field generator (x40). The first magnetic field generator (x30), the second magnetic field generator (x40) and the magnetized plate are preferably substantially centered with respect to each other. As used herein, the term "indicia" is intended to mean designs and patterns, including but not limited to symbols, alphanumeric symbols, motifs, letters, words, numbers, logos, and drawings. One or more surface reliefs, engravings, and / or cutouts of the magnetized plate bearing the indicia are transferred to the uncured OEL by locally modifying the magnetic field generated by the magnetic assembly (x00) described herein. Suitable examples of magnetized plates (x60) containing one or more surface reliefs, engravings, and / or cutouts as described herein for the present invention can be found in WO 2005 / 002866 A1, WO 2008 / 046702 A1, WO 2008 / 139373 A1, WO 2018 / 019594 A1, and WO 2018 / 033512 A1.

[0064]

[0063] The magnetized plate including one or more engravings and / or notches described herein may be made of any mechanically processable soft or hard magnetic material. Hard magnetic materials include, but are not limited to, those mentioned above with respect to the first dipole magnet (x31) of the first magnetic field generator (x30) and the second dipole magnet (x41) of the second magnetic field generator (x40). Soft magnetic materials are characterized by low coercivity and high magnetic permeability μ. The respective coercivity is greater than 1000 Am, measured according to IEC 60404-1:2000, to allow fast magnetization and demagnetization.-1 Suitable soft magnetic materials have a maximum relative magnetic permeability μ Rmax is at least 5. Here, the relative permeability μ R is the magnetic permeability μ of the material relative to the magnetic permeability μ of free space (μ R =μ / μ0)(Magnetic Materials,Fundamentals and Applications,2 ndEd., Nicola A. Spaldin, p.16-17, Cambridge University Press, 2011). Regarding soft magnetic materials, for example, (1) Handbook of Condensed Matter and Materials Data, Chap. 4.3.2, Soft Magnetic Materials, p. 758-793, and Chap. 4.3.4, Magnetic Oxides, p. 811-813, Springer 2005, (2) Ferromagnetic Materials, Vol. 1, Iron, Cobalt and Nickel,p.1-70,Elsevier 1999,(3)Ferromagnetic Materials,Vol.2,Chap. 2,Soft Magnetic Metallic Materials,p.55-188,and Chap.3,Ferrites for non-microwave Applications,p.189-241,Elsevier 1999,(4)Electric and Magnetic Properties of Metals,C.Moosbrugger,Chap.8,Magnetically Soft Materials,p.196-209,ASM (5) Handbook of modern Ferromagnetic Materials, Chap. 9, High-permeability High-frequency Metal Strip, p. 155-182, Kluwer Academic Publishers, 2002, and (6) Smithells Metals Reference Book, Chap. 20.3, Magnetically Soft Materials, p. 20-9 to 20-16, Butterworth-Heinemann Ltd, 1992.

[0065]

[0064] The magnetized plate described herein is preferably a polymer-bonded plate of soft or hard magnetic material, i.e. a magnetized plate made of a composite material including a polymer. The polymer (e.g. a polymer such as rubber or plastic) acts as a structural binder and the soft or hard magnetic material acts as an extender or filler. A magnetized plate made of a composite material including a polymer and a soft or hard magnetic material advantageously combines the desired magnetic properties (e.g. high coercivity of a high magnetic material and high permeability of a soft magnetic material) with the desired mechanical properties (flexibility, machinability, impact resistance) of a malleable metal or plastic material. Suitable polymers include rubber-type flexible materials such as nitrile rubber, EPDM hydrocarbon rubber, polyisoprene, polyamide (PA), polyphenylene sulfide (PPS), and chlorosulfonated polyethylene.

[0066]

[0065] Magnetized plates made of a composite material including polymer and permanent magnetic powder can be obtained from a number of different sources, such as Group ARNOLD (Plastiform®) or Materiali Magnetici, Albairate, Milano, Italy (Plastoferrite).

[0067]

[0066] The magnetized plates described herein, particularly those comprised of composites including the polymers described herein and soft or hard magnetic materials, may be obtained in any desired size and form (e.g., as thin, flexible plates that can be bent and mechanically machined (e.g., cut to a predetermined size or shape) using commonly available mechanical cutting tools and machines, as well as air or liquid jet cutting, or laser cutting tools).

[0068]

[0067] The one or more surface engravings and / or cutouts of the magnetized plate described herein, in particular the magnetized plate composed of a composite including the polymer and soft or hard magnetic material described herein, may be produced by any cutting or engraving method known in the art, including casting, molding, manual engraving or mechanical ablation tools (including computer controlled engraving tools), ablation tools selected from the group consisting of gas or liquid jet ablation tools, chemical etching, electrochemical etching, and laser ablation tools (e.g., CO 2- , Nd-YAG, or excimer lasers). Also, as will be appreciated by those skilled in the art and as described herein, the magnetized plates (x60) described herein, particularly those made of composites including polymers and soft or hard magnetic materials described herein, can be cut or molded to a particular size and shape rather than engraved. Holes can be cut out or cut-out pieces can be assembled to a support.

[0069]

[0068] The engravings and cutouts of the magnetized plate (x60), in particular those made of a composite material including a polymer and a soft or hard magnetic material as described herein, may be filled with a polymer or may contain a filler. In the case of the embodiment in which the magnetized plate is made of a hard magnetic material, the filler may be a soft magnetic material that modifies the magnetic flux at the engraving / cutout location or may be any other type of magnetic or non-magnetic material that modifies the magnetic field characteristics or simply creates a smooth surface. The magnetized plate, in particular those made of a composite material including a polymer and a soft or hard magnetic material as described herein, may also be surface treated to facilitate contact with the substrate, thereby reducing friction, wear, and / or electrostatic charging in high-speed printing applications.

[0070] The present invention further provides a printing apparatus comprising a rotating magnetic cylinder and one or more magnetic assemblies (x00) as described herein, said one or more magnetic assemblies (x00) being mounted in circumferential or axial grooves of the rotating magnetic cylinder, and a printing apparatus comprising a flatbed printing unit and one or more magnetic assemblies (x00) as described herein, said one or more magnetic assemblies being mounted in recesses in the flatbed printing unit. The present invention further provides a use of said printing apparatus for producing an optical effect layer (OEL) as described herein on a substrate as described herein.

[0071]

[0070] The rotating magnetic cylinder is intended for use in, with, or as part of a printing or coating apparatus and supports one or more of the magnetic assemblies described herein. In one embodiment, the rotating magnetic cylinder is part of a rotary, sheet-fed, or web-fed industrial printing press operating continuously at high printing speeds.

[0072]

[0071] A flatbed printing unit is intended for use in, with, or as part of a printing or coating apparatus and supports one or more of the magnetic assemblies described herein. In one embodiment, the flatbed printing unit is part of a non-continuously operating sheet-fed industrial printing press.

[0073]

[0072] A printing apparatus with a rotating magnetic cylinder as described herein or a flatbed printing unit as described herein may comprise a substrate feeder for feeding a substrate as described herein having a layer of non-spherical magnetic or magnetisable pigment particles as described herein, whereby the magnetic assembly generates a magnetic field that acts on and orients the pigment particles to form an OEL as described herein. In one embodiment of a printing apparatus with a rotating magnetic cylinder as described herein, the substrate is fed by the substrate feeder in the form of a sheet or web. In one embodiment of a printing apparatus with a flatbed printing unit as described herein, the substrate is fed in the form of a sheet.

[0074] A printing apparatus with a rotating magnetic cylinder as described herein or a flatbed printing unit as described herein may comprise a coating or printing unit for applying a radiation curable coating composition comprising non-spherical magnetic or magnetisable pigment particles as described herein to a substrate as described herein, the radiation curable coating composition comprising non-spherical magnetic or magnetisable pigment particles that are oriented by a magnetic field generated by a magnetic assembly as described herein to form an optical effect layer (OEL). In one embodiment of a printing apparatus with a rotating magnetic cylinder as described herein, the coating or printing unit operates according to a rotational continuous process. In one embodiment of a printing apparatus with a flatbed printing unit as described herein, the coating or printing unit operates according to a linear discontinuous process.

[0075]

[0074] A printing apparatus having a rotating magnetic cylinder as described herein or a flatbed printing unit as described herein may also include a curing unit that fixes the orientation and position of the non-spherical magnetic or magnetizable pigment particles to produce an optical effect layer (OEL) by at least partially curing a radiation curable coating composition containing non-spherical magnetic or magnetizable pigment particles magnetically oriented by the magnetic assembly as described herein.

[0076]

[0075] The present invention provides a process and method for producing an optical effect layer (OEL) as described herein on a substrate (x20) as described herein, and the optical effect layer (OEL) obtained thereby, the process comprising the step of: i) applying a radiation curable coating composition in a first state comprising the non-spherical magnetic or magnetisable pigment particles as described herein to a surface of the substrate (x20) to form a coating layer (x10). The radiation curable coating composition is in a first state to form a coating layer (x10). The radiation curable coating composition is in a first state, i.e. a liquid or pasty state, and is sufficiently wet or pliable so that the non-spherical magnetic or magnetisable pigment particles dispersed in the radiation curable coating composition are free to move, rotate and / or orient by exposure to a magnetic field.

[0077]

[0076] Step i) described herein may be performed by a coating process, such as roller and spray coating processes, or a printing process. Step i) described herein is preferably performed by a printing process selected from the group consisting of screen printing, gravure printing, flexography, inkjet printing, and intaglio printing (also referred to in the art as copperplate intaglio printing and steel die intaglio printing), more preferably selected from the group consisting of screen printing, gravure printing, and flexography.

[0078]

[0077] Following application (step i) of the radiation curable coating composition described herein to the surface of the substrate (x20) described herein, or partially simultaneously, at least a portion of the non-spherical magnetic or magnetizable pigment particles are orientated (step ii) by exposing the radiation curable coating composition to the static magnetic field of the magnetic assembly (x00) described herein, thereby aligning at least a portion of the non-spherical magnetic or magnetizable pigment particles along the magnetic field lines generated by the magnetic assembly (x00).

[0079]

[0078] After or partly simultaneously with the step of orienting / aligning at least a portion of the non-spherical magnetic or magnetisable pigment particles by application of a magnetic field as described herein, the orientation of the non-spherical magnetic or magnetisable pigment particles is fixed or arrested. Thus, it is noted that the radiation curable coating composition must have a first state, i.e. a liquid or pasty state, sufficiently wet or soft so that the non-spherical magnetic or magnetisable pigment particles dispersed therein can freely move, rotate and / or be oriented by exposure to a magnetic field, and must also have a second, hardened (e.g. solid) state, in which the non-spherical magnetic or magnetisable pigment particles are fixed or arrested in their respective positions and orientations.

[0080]

[0079] In view of the above, the process for producing an optical effect layer (OEL) on a substrate (x20) as described herein comprises at least partially curing the radiation curable coating composition of step ii) to a second state iii) so as to fix the non-spherical magnetic or magnetisable pigment particles in their adopted positions and orientations. The step iii) of at least partially curing the radiation curable coating composition may be performed after or partially simultaneously with the step (step ii)) of orienting / aligning at least a portion of the non-spherical magnetic or magnetisable pigment particles by application of a magnetic field as described herein. The step iii) of at least partially curing the radiation curable coating composition is preferably performed partially simultaneously with the step (step ii)) of orienting / aligning at least a portion of the non-spherical magnetic or magnetisable pigment particles by application of a magnetic field as described herein. By "partially simultaneously" it is meant that both steps are performed partially simultaneously, i.e. there is a partial overlap in the timing of the execution of each step. In the context described herein, it should be understood that if curing is performed partly simultaneously with the orientation step ii), the curing is effective after the orientation so that the pigment particles have time to orient before full or partial curing or solidification of the OEL.

[0081]

[0080] The process for producing an optical effect layer (OEL) described herein may further comprise a step (step ii2)) of exposing the coating layer (x10) to a dynamic magnetic field of a device, prior to or at least partially simultaneously with step ii), so as to biaxially orient at least a portion of the platelet-shaped magnetic or magnetisable pigment particles, which step (step ii2)) is carried out prior to or at least partially simultaneously with step ii) and prior to step iii). A process comprising a step of exposing a coating composition to a dynamic magnetic field of a device, so as to biaxially orient at least a portion of the platelet-shaped magnetic or magnetisable pigment particles, is disclosed in WO 2015 / 086257 A1. After exposure of the coating layer (x10) to the dynamic magnetic field of the magnetic assembly (x30) as described in WO 2015 / 086257 A1, while the coating layer (x10) is still wet or soft so that the platelet-shaped magnetic or magnetisable pigment particles therein can further move and rotate, the platelet-shaped magnetic or magnetisable pigment particles are further reoriented using the device described herein. Performing a biaxial orientation means orienting the platelet-shaped magnetic or magnetisable pigment particles such that two main axes are constrained. That is to say, each platelet-shaped magnetic or magnetisable pigment particle is considered to have a long axis in the plane of the pigment particle and a short axis perpendicular to the plane of the pigment particle. The long and short axes of the platelet-shaped magnetic or magnetisable pigment particles are each oriented according to the dynamic magnetic field. In practice, this results in magnetic or magnetisable pigment particles that are close to each other in space being essentially parallel to each other. To perform a biaxial orientation, the magnetic or magnetisable pigment particles need to be subjected to an external magnetic field that is strongly time-dependent.

[0082]

[0081] A particularly preferred device for biaxially orienting magnetic or magnetisable pigment particles is disclosed in EP 2 157 141 A1. The device disclosed in EP 2 157 141 A1 applies a dynamic magnetic field that changes direction causing the magnetic or magnetisable pigment particles to rapidly vibrate until both major axes, X and Y, are substantially parallel to the substrate surface. That is to say, the magnetic or magnetisable pigment particles rotate until they come into a stable sheet-like configuration with X and Y axes substantially parallel to the substrate surface and flatten in said two dimensions. Another particularly preferred device for biaxially orienting magnetic or magnetisable pigment particles comprises a linear permanent magnet Halbach array, i.e. an assembly with a number of magnets with different magnetisation directions. A detailed description of Halbach permanent magnets is given by ZQ Zhu and D. Howe (Halbach permanent magnet machines and applications: a review, IEE. Proc. Electric Power Appl., 2001, 148, p. 299-308). The magnetic field generated by such a Halbach array has the property of being concentrated on one side and weakening to almost zero on the other side. WO 2016 / 083259 A1 discloses a suitable device for biaxially orienting magnetic or magnetizable pigment particles, comprising a Halbach cylinder assembly. Another particularly preferred device for biaxially orienting magnetic or magnetizable pigment particles is a rotating magnet, including disk-shaped rotating magnets or magnetic assemblies that are essentially magnetized along their diameter. Suitable rotating magnets or magnetic assemblies are described in US Patent Application Publication No. 2007 / 0172261 A1, which generate a radially symmetric time-variable magnetic field to allow biaxial orientation of magnetic or magnetizable pigment particles in an uncured or unsolidified coating composition. These magnets or magnetic assemblies are driven by a shaft (or spindle) connected to an external motor. China Patent No. 102529326 B discloses an example of an apparatus with a rotating magnet that may be suitable for biaxial orientation of magnetic or magnetizable pigment particles.In one preferred embodiment, a suitable device for biaxially orienting magnetic or magnetisable pigment particles is a shaftless, disk-shaped rotating magnet or magnetic assembly constrained in a housing made of a non-magnetic, preferably non-conductive, material and driven by one or more coils of magnet wire wound around the housing. Examples of such shaftless, disk-shaped rotating magnet or magnetic assemblies are disclosed in WO 2015 / 082344 A1, WO 2016 / 026896 A1 and WO 2018 / 141547 A1.

[0083]

[0082] The first and second states of the radiation curable coating composition are provided by using certain radiation curable coating compositions. For example, the components of the radiation curable coating composition other than the non-spherical magnetic or magnetisable pigment particles may be in the form of inks or radiation curable coating compositions such as those used in security applications (e.g. banknote printing). The above-mentioned first and second states are provided by using a material that becomes more viscous in response to exposure to electromagnetic radiation. That is, the fluid binder material is transformed by curing or solidifying into a second state in which the non-spherical magnetic or magnetisable pigment particles are fixed in their current positions and orientations and cannot move or rotate within the binder material.

[0084]

[0083] As known to those skilled in the art, the components included in, and physical properties of, a radiation curable coating composition applied onto a surface such as a substrate must meet the requirements of the process used to transfer the radiation curable coating composition to the substrate surface. As a result, the binder materials included in the radiation curable coating compositions described herein are typically selected from materials known in the art and are dependent on the coating or printing process used to apply the radiation curable coating composition and the radiation curing process selected.

[0085]

[0084] In the optical effect layer (OEL) described herein, the non-spherical magnetic or magnetisable pigment particles described herein are dispersed in a cured / solidified radiation curable coating composition comprising a cured binder material that fixes / freezes the orientation of the magnetic or magnetisable pigment particles. The cured binder material is at least partially transparent to electromagnetic radiation of various wavelengths comprised between 200 nm and 2500 nm. Thus, the binder material, at least in its cured or solid state (also referred to herein as the second state), is at least partially transparent to electromagnetic radiation of various wavelengths comprised between 200 nm and 2500 nm, i.e., within a wavelength range that includes the infrared, visible, and UV (ultraviolet) portions of the electromagnetic spectrum, commonly referred to as the "optical spectrum", such that the reflectivity of the cured or solid state particles contained therein and their respective orientations can be discerned through the binder material. The cured binder material is at least partially transparent to electromagnetic radiation of various wavelengths preferably comprised between 200 nm and 800 nm, more preferably between 400 nm and 700 nm. In this specification, the term "transparent" indicates that the transmission of electromagnetic radiation through a 20 μm layer of the cured binder material present in the OEL (not including the platelet-shaped magnetic or magnetizable pigment particles but including all other optional components of the OEL, if any) is at least 50%, more preferably at least 60%, even more preferably at least 70% at the relevant wavelength(s). This can be determined by measuring the transmission of a test piece of the cured binder material (not including the non-spherical magnetic or magnetizable pigment particles) according to established test methods, such as DIN 5036-3 (1979-11). If the OEL serves as a covert security feature, technical means are usually required to detect the (complete) optical effect that the OEL produces under each lighting condition, including the selected non-visible wavelengths. Such detection requires that a wavelength of incident radiation is selected outside the visible range (e.g. in the near UV range). The infrared, visible, and ultraviolet portions of the electromagnetic spectrum correspond approximately to wavelength ranges of 700-2500 nm, 400-700 nm, and 200-400 nm, respectively.

[0086]

[0085] As mentioned above, the radiation curable coating compositions described herein depend on the coating or printing process used to apply the radiation curable coating composition and the curing process selected. Curing of the radiation curable coating composition preferably involves a chemical reaction that is not reversible by a simple temperature increase (e.g. up to 80°C) that may occur during normal use of an article with an OEL described herein. The term "curing" or "curable" refers to a process in which at least one component in the applied radiation curable coating composition is transformed by chemical reaction, crosslinking, or polymerization into a polymeric material having a higher molecular weight than the starting material. Radiation curing is advantageous because exposure to curing radiation instantly increases the viscosity of the radiation curable coating composition, reducing further migration of the pigment particles and thus reducing information loss after the magnetic orientation step. The curing step (step iii)) is preferably carried out by radiation curing or electron beam radiation curing, including UV-visible radiation curing, more preferably UV-visible radiation curing.

[0087]

[0086] Thus, radiation curable coating compositions suitable for the present invention include radiation curable compositions that can be cured by UV-visible radiation (hereinafter referred to as UV-visible radiation) or electron beam radiation (hereinafter referred to as EB radiation). Radiation curable compositions are known in the art and can be found in standard textbooks such as the "Chemistry & Technology of UV & EB Formulation for Coatings, Inks & Paints" series by C.Lowe, G.Webster, S.Kessel, and I.McDonald, Vol. 4, published in 1996 by John Wiley & Sons in association with SITA Technology Limited. According to a particularly preferred embodiment of the present invention, the radiation curable coating composition described herein is a UV-visible radiation curable coating composition. Thus, radiation curable coating compositions comprising the non-spherical magnetic or magnetisable pigment particles described herein are preferably at least partially cured by UV-visible radiation, preferably narrow band LED light in the UV-A (315-400 nm) or blue (400-500 nm) spectral region, most preferably high power LED sources emitting in the 350 nm to 450 nm spectral region with typical emission bandwidths in the range of 20 nm to 50 nm. It is also possible to increase the cure speed of radiation curable coating compositions by the use of UV radiation from mercury or doped mercury lamps.

[0088]

[0087] The UV and visible radiation curable coating composition preferably comprises one or more compounds selected from the group consisting of radically curable compounds and cationically curable compounds. The UV and visible radiation curable coating composition described herein may be a hybrid system and comprises a mixture of one or more cationically curable compounds and one or more radically curable compounds. The cationically curable compounds cure by a cationic mechanism which typically involves the activation by radiation of one or more photoinitiators which cure the radiation curable coating composition by reaction and / or crosslinking of monomers and / or oligomers by liberating a cationic species such as an acid to initiate the cure. The radically curable compounds cure by a free radical mechanism which typically involves the activation by radiation of one or more photoinitiators which generate radicals to initiate the polymerization to cure the radiation curable coating composition. Different photoinitiators can be used depending on the monomers, oligomers or prepolymers used to make the binder contained in the UV and visible radiation curable coating composition described herein. Suitable examples of free radical photoinitiators are known to those skilled in the art and include, but are not limited to, acetophenone, benzophenone, benzyl dimethyl ketal, α-amino ketone, α-hydroxy ketone, phosphine oxide, and phosphine oxide derivatives, as well as mixtures of two or more thereof. Suitable examples of cationic photoinitiators are known to those skilled in the art and include, but are not limited to, onium salts, such as organic iodonium salts (e.g., diaryliodonium salts), oxonium salts (e.g., triaryloxonium salts), and sulfonium salts (e.g., triarylsulfonium salts), as well as mixtures of two or more thereof.Other examples of useful photoinitiators can be found in standard textbooks such as "Photoinitiators for Free Radical Cationic and Anionic Polymerization" 2nd Edition by JV Crivello and K. Dietliker, Volume 3 of "Chemistry & Technology of UV & EB Formulation for Coatings, Inks & Paints", edited by G. Bradley and published in 1998 by John Wiley & Sons in partnership with SITA Technology Limited. It may also be advantageous to include a sensitizer in conjunction with one or more photoinitiators to achieve efficient curing. Common examples of suitable photosensitizers include, but are not limited to, isopropyl-thioxanthone (ITX), 1-chloro-2-propoxy-thioxanthone (CPTX), 2-chloro-thioxanthone (CTX), and 2,4-diethyl-thioxanthone (DETX), and mixtures of two or more thereof. The one or more photoinitiators included in the UV and visible radiation curable coating composition are preferably present in a total amount of from about 0.1% to about 20% by weight, more preferably from about 1% to about 15% by weight, the weight percentages being based on the total weight of the UV and visible radiation curable coating composition.

[0089]

[0088] The radiation curable coating compositions described herein may further comprise one or more marker substances or traceability additives and / or one or more machine readable materials selected from the group consisting of magnetic materials (different from the platelet-like magnetic or magnetisable pigment particles described herein), luminescent materials, conductive materials, and infrared absorbing materials. As used herein, the term "machine readable material" refers to a material (x32) that, when included in a layer, can provide a method of authenticating the layer or an article containing the layer by use of a specific authentication device.

[0090]

[0089] The radiation curable coating compositions described herein may further comprise one or more colouring components selected from the group consisting of organic pigment particles, inorganic pigment particles and organic dyes, and / or non-magnetic or non-magnetisable optically variable pigments, and / or one or more additives, including but not limited to compounds and materials used to adjust the physical, rheological and chemical parameters of the radiation curable coating composition, such as viscosity (e.g. solvents, thickeners and surfactants), consistency (e.g. cure inhibitors, fillers and plasticisers), foamability (e.g. defoamers), lubricity (waxes, oils), UV stability (light stabilizers), adhesion, antistatic properties, shelf life (polymerisation inhibitors), gloss, etc. The additives described herein may be present in the radiation curable coating composition in amounts and forms known in the art, such as so-called nanomaterials, where at least one of the dimensions of the additive is in the range of 1-1000 nm.

[0091]

[0090] The radiation curable coating composition described herein comprises the non-spherical magnetic or magnetizable pigment particles described herein. The non-spherical magnetic or magnetizable pigment particles are preferably present in an amount of from about 2% to about 40% by weight, more preferably from about 4% to about 30% by weight. This weight percentage is based on the total weight of the radiation curable coating composition including the binder material, the non-spherical magnetic or magnetizable pigment particles, and other optional components of the radiation curable coating composition.

[0092]

[0091] The non-spherical magnetic or magnetisable pigment particles described herein are defined to be non-isotropic in shape and therefore non-isotropic in reflectivity to incident electromagnetic radiation to which at least a portion of the cured or solidified binder material is transparent. As used herein, the term "non-isotropic reflectivity" indicates that the proportion of incident radiation from a first angle that is reflected by the particle in a particular (viewing) direction (second angle) is a function of the particle's orientation, i.e., the magnitude of reflection in the viewing direction may vary as the particle's orientation changes relative to the first angle. More preferably, the non-spherical magnetic or magnetisable pigment particles described herein are non-isotropic in reflectivity to incident electromagnetic radiation in some or all of the wavelength range from about 200 to about 2500 nm, more preferably from about 400 to about 700 nm, such that a change in particle orientation changes the reflection by the particle in a particular direction. As known to those skilled in the art, the magnetic or magnetizable pigment particles described herein differ from conventional pigments in that they exhibit reflectivity, color, or both that depend on particle orientation, whereas conventional pigment particles exhibit the same color and reflectivity regardless of particle orientation. The non-spherical magnetic or magnetizable pigment particles described herein are preferably platelet-shaped magnetic or magnetizable pigment particles.

[0093]

[0092] Suitable examples of non-spherical magnetic or magnetisable pigment particles as described herein include, but are not limited to, pigment particles comprising a magnetic metal selected from the group consisting of cobalt (Co), iron (Fe), gadolinium (Gd) and nickel (Ni), magnetic alloys of iron, chromium, manganese, cobalt, nickel and mixtures of two or more thereof, magnetic oxides of chromium, manganese, cobalt, iron, nickel and mixtures of two or more thereof, and mixtures of two or more thereof. The term "magnetic" with respect to metals, alloys and oxides covers ferromagnetic or ferrimagnetic metals, alloys and oxides. The magnetic oxides of chromium, manganese, cobalt, iron, nickel or mixtures of two or more thereof may be pure or mixed oxides. Examples of magnetic oxides include hematite (Fe2O3), magnetite (Fe3O4), chromium dioxide (CrO2), magnetic ferrite (MFe2O4), magnetic spinel (MR2O4), magnetic hexaferrite (MFe 12 O 19 Examples of iron oxides include, but are not limited to, iron oxides such as magnetic orthoferrite (RFeO3), magnetic garnet (M3R2(AO4)3), etc., where M represents a divalent metal, R represents a trivalent metal, and A represents a tetravalent metal.

[0094]

[0093] Examples of non-spherical magnetic or magnetisable pigment particles as described herein include, but are not limited to, pigment particles comprising a magnetic layer M composed of one or more of magnetic metals such as cobalt (Co), iron (Fe), gadolinium (Gd) or nickel (Ni) and magnetic alloys of iron, chromium, cobalt or nickel. The platelet-shaped magnetic or magnetisable pigment particles may also be multi-layered structures comprising one or more further layers. The one or more further layers are preferably independently composed of one or more materials selected from the group consisting of magnesium fluoride (MgF2), aluminum fluoride (AlF3), cerium fluoride (CeF3), lanthanum fluoride (LaF3), sodium aluminum fluoride (e.g., Na3AlF6), neodymium fluoride (NdF3), samarium fluoride (SmF3), barium fluoride (BaF2), calcium fluoride (CaF2), lithium fluoride (LiF), preferably a metal fluoride such as magnesium fluoride (MgF2), silicon oxide (SiO), silicon dioxide (SiO2), titanium oxide (TiO2), zinc sulfide (ZnS), and aluminum oxide (Al2O3), more preferably silicon dioxide (SiO2). a layer A comprised of a metal and a metal alloy, preferably a reflective metal and a reflective metal alloy, more preferably one or more materials selected from the group consisting of aluminum (Al), silver (Ag), copper (Cu), gold (Au), platinum (Pt), tin (Sn), titanium (Ti), palladium (Pd), rhodium (Rh), niobium (Nb), chromium (Cr), nickel (Ni), and alloys thereof, still more preferably one or more materials selected from the group consisting of aluminum (Al), chromium (Cr), nickel (Ni), and alloys thereof, even more preferably aluminum (Al); or a combination of one or more layers A as described above and one or more layers B as described above.Typical examples of platelet-shaped magnetic or magnetisable pigment particles that are multi-layered as described above include, but are not limited to, A / M multi-layered structures, A / M / A multi-layered structures, A / M / B multi-layered structures, A / B / M / A multi-layered structures, A / B / M / B multi-layered structures, A / B / M / B / A multi-layered structures, B / M multi-layered structures, B / M / B multi-layered structures, B / A / M / A multi-layered structures, B / A / M / B multi-layered structures, B / A / M / B / A multi-layered structures, where layer A, magnetic layer M and layer B are selected from the layers described above.

[0095] According to one embodiment, at least a part of the non-spherical magnetic or magnetisable pigment particles described herein is a multi-layer structure of dielectric / reflector / magnetic / reflector / dielectric, the reflector layer described herein being independently selected from the group consisting of metals and metal alloys as described above for the B layer, the dielectric layer being independently selected from the group consisting of materials as described above for the A layer, and the magnetic layer preferably comprising one or more of the magnetic metals or magnetic alloys as described above for the M layer. Alternatively, the multi-layer structure of dielectric / reflector / magnetic / reflector / dielectric described herein may be a multi-layer pigment particle considered safe for human health and the environment, the magnetic layer comprising a substantially nickel-free magnetic alloy with a composition of about 40% to about 90% by weight iron, about 10% to about 50% by weight chromium, and about 0% to about 30% by weight aluminum.

[0096]

[0095] At least a portion of the non-spherical magnetic or magnetisable pigment particles described herein may be composed of non-spherical chromatic magnetic or magnetisable pigment particles and / or non-spherical magnetic or magnetisable pigment particles without chromatic change properties. Preferably, at least a portion of the non-spherical magnetic or magnetisable pigment particles described herein are composed of non-spherical chromatic magnetic or magnetisable pigment particles. The overt security feature provided by the chromatic change properties of the non-spherical chromatic magnetic or magnetisable pigment particles allows an article or security document having an ink, radiation curable coating composition, coating or layer comprising the non-spherical chromatic magnetic or magnetisable pigment particles described herein to be easily detected, recognised and / or distinguished from possible counterfeits by human senses alone, in addition to which the optical properties of the non-spherical chromatic magnetic or magnetisable pigment particles may be used as a machine-readable tool for optical effect layer (OEL) recognition. Thus, the optical properties of the non-spherical chromophoric magnetic or magnetisable pigment particles may be simultaneously used as a covert or semi-covert security feature in an authentication process in which the optical (e.g. spectral) properties of the pigment particles are analysed. The use of non-spherical chromophoric magnetic or magnetisable pigment particles in radiation curable coating compositions which produce OELs makes the OELs more relevant as a security feature in security document applications, since such materials (i.e. non-spherical chromophoric magnetic or magnetisable pigment particles) are intended for the security document printing industry and are not generally commercially available.

[0097]

[0096] Furthermore, the non-spherical magnetic or magnetisable pigment particles described herein are machine-readable due to their magnetic properties, so that radiation-curable coating compositions comprising these pigment particles may be adapted to be detected, for example, by a specific magnetic detector. Thus, radiation-curable coating compositions comprising the non-spherical magnetic or magnetisable pigment particles described herein can be used as covert or semi-covert security elements (authentication tools) for security documents.

[0098] As mentioned above, the non-spherical magnetic or magnetisable pigment particles are preferably at least partially constituted by non-spherical chromic magnetic or magnetisable pigment particles, more preferably these can be selected from the group consisting of non-spherical magnetic thin film interference pigment particles, non-spherical magnetic cholesteric liquid crystal pigment particles, non-spherical interference coated pigment particles comprising a magnetic material, and mixtures of two or more thereof.

[0099]

[0098] Magnetic thin film interference pigment particles are known to those skilled in the art and are disclosed, for example, in U.S. Pat. No. 4,838,648, WO 2002 / 073250 A2, EP 0 686 675 B1, WO 2003 / 000801 A2, U.S. Pat. No. 6,838,166, WO 2007 / 131833 A1, EP 2 402 401 A1 and references cited therein. The magnetic thin film interference pigment particles preferably comprise pigment particles having a 5-layer Fabry-Perot multilayer structure, and / or pigment particles having a 6-layer Fabry-Perot multilayer structure, and / or pigment particles having a 7-layer Fabry-Perot multilayer structure.

[0100]

[0099] A preferred five-layer Fabry-Perot multilayer structure consists of a multilayer structure of absorber / dielectric / reflector / dielectric / absorber, where the reflector and / or absorber are also magnetic layers, preferably the reflector and / or absorber are magnetic layers comprising nickel, iron, and / or cobalt, magnetic alloys comprising nickel, iron, and / or cobalt, and / or magnetic oxides comprising nickel (Ni), iron (Fe), and / or cobalt (Co).

[0101]

[0100] A preferred six-layer Fabry-Perot multilayer structure consists of the following multilayer structure: absorber / dielectric / reflector / magnetic / dielectric / absorber.

[0102] A preferred seven-layer Fabry-Perot multilayer structure consists of an absorber / dielectric / reflector / magnetic / reflector / dielectric / absorber multilayer structure as disclosed in US Pat. No. 4,838,648.

[0103]

[0102] The reflector layers described herein are preferably independently comprised 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 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 aluminum (Al), chromium (Cr), nickel (Ni), and alloys thereof, still more preferably aluminum (Al). The dielectric layers are preferably independently composed of one or more materials selected from the group consisting of metal fluorides such as magnesium fluoride (MgF2), aluminum fluoride (AlF3), cerium fluoride (CeF3), lanthanum fluoride (LaF3), sodium aluminum fluoride (e.g., Na3AlF6), neodymium fluoride (NdF3), samarium fluoride (SmF3), barium fluoride (BaF2), calcium fluoride (CaF2), lithium fluoride (LiF), metal oxides such as silicon oxide (SiO), silicon dioxide (SiO2), titanium oxide (TiO2), aluminum oxide (Al2O3), more preferably magnesium fluoride (MgF2) and silicon dioxide (SiO2), even more preferably magnesium fluoride (MgF2). The absorber layers are independently composed of one or more materials preferably selected from the group consisting of aluminum (Al), silver (Ag), copper (Cu), palladium (Pd), platinum (Pt), titanium (Ti), vanadium (V), iron (Fe), tin (Sn), tungsten (W), molybdenum (Mo), rhodium (Rh), niobium (Nb), chromium (Cr), nickel (Ni), metal oxides thereof, metal sulfides, metal carbides, and metal alloys, more preferably selected from the group consisting of chromium (Cr), nickel (Ni), iron (Fe), metal oxides thereof, and metal alloys, and even more preferably selected from the group consisting of chromium (Cr), nickel (Ni), and metal alloys thereof.The magnetic layer preferably comprises nickel (Ni), iron (Fe) and / or cobalt (Co), a magnetic alloy comprising nickel (Ni), iron (Fe) and / or cobalt (Co) and / or a magnetic oxide comprising nickel (Ni), iron (Fe) and / or cobalt (Co). If magnetic thin film interference pigment particles comprising a seven-layer Fabry-Perot structure are preferred, it is particularly preferred that the magnetic thin film interference pigment particles have a seven-layer Fabry-Perot absorber / dielectric / reflector / magnetic / reflector / dielectric / absorber multilayer structure consisting of a Cr / MgF2 / Al / M / Al / MgF2 / Cr multilayer structure, where M is a magnetic layer comprising nickel (Ni), iron (Fe) and / or cobalt (Co), a magnetic alloy comprising nickel (Ni), iron (Fe) and / or cobalt (Co) and / or a magnetic oxide comprising nickel (Ni), iron (Fe) and / or cobalt (Co).

[0104]

[0103] The magnetic thin film interference pigment particles described herein are believed to be safe for human health and the environment and may be multi-layer pigment particles based on, for example, a 5-layer Fabry-Perot multi-layer, a 6-layer Fabry-Perot multi-layer, and a 7-layer Fabry-Perot multi-layer, said pigment particles comprising one or more magnetic layers comprising a substantially nickel-free magnetic alloy of a composition comprising, by weight, about 40% to about 90% iron, about 10% to about 50% chromium, and about 0% to about 30% aluminum. Typical examples of multi-layer pigment particles believed to be safe for human health and the environment can be found in EP 2 402 401 A1, the entire contents of which are incorporated herein by reference.

[0105]

[0104] The magnetic thin film interference pigment particles described herein are typically manufactured by conventional deposition techniques of the different required layers onto a web. After the desired number of layers have been deposited, for example by physical vapor deposition (PVD), chemical vapor deposition (CVD) or electrolytic deposition, the layer stack is removed from the web by dissolving the release layer in a suitable solvent or by peeling the material from the web. The material thus obtained is then milled to obtain platelet-like pigment particles, which must be further processed by grinding, milling (e.g., jet milling process, etc.) or in any suitable manner to obtain pigment particles of the required size. The resulting product consists of flat platelet-like pigment particles with broken edges, irregular shapes and different aspect ratios. Details regarding the preparation of suitable platelet-like magnetic thin film interference pigment particles can be found, for example, in EP 1 710 756 A1 and EP 1 666 546 A1, which are incorporated herein by reference.

[0106]

[0105] Suitable magnetic cholesteric liquid crystal pigment particles exhibiting color-changing properties include, but are not limited to, magnetic single-layer cholesteric liquid crystal pigment particles and magnetic multi-layer cholesteric liquid crystal pigment particles. Such pigment particles are disclosed, for example, in WO 2006 / 063926 A1, U.S. Pat. No. 6,582,781, and U.S. Pat. No. 6,531,221. WO 2006 / 063926 A1 discloses a monolayer and pigment particles obtained therefrom having high brightness and color-changing properties as well as specific properties such as magnetizability. The disclosed monolayer and pigment particles obtained by grinding the monolayer include a three-dimensionally crosslinked cholesteric liquid crystal mixture and magnetic nanoparticles. U.S. Pat. No. 6,582,781 and U.S. Pat. No. 6,410,130 disclose a cholesteric liquid crystal pigment having a three-dimensionally crosslinked cholesteric liquid crystal mixture and magnetic nanoparticles having a three-dimensionally crosslinked cholesteric liquid crystal mixture ... 1 / B / A 2 The present invention discloses a cholesteric multi-layer pigment particle of 1 and A 2 may be the same or different and each contain at least one cholesteric layer. B is layer A 1 and A 2The intermediate layer absorbs all or part of the light transmitted from the substrate and imparts magnetic properties. U.S. Patent No. 6,531,221 discloses platelet-like cholesteric multi-layer pigment particles in an arrangement A / B, optionally including C, where A and C are absorbing layers containing pigment particles imparting magnetic properties, and B is a cholesteric layer.

[0107]

[0106] Suitable interference coated pigments comprising one or more magnetic materials include, but are not limited to, structures consisting of a substrate selected from the group consisting of a core coated with one or more layers, where at least one of the core or the one or more layers is magnetic. For example, suitable interference coated pigments include a core composed of a magnetic material as described above, coated with one or more layers composed of one or more metal oxides, or have a structure consisting of a core composed of synthetic or natural mica, layered silicates (e.g., talc, kaolin, and sericite), glass (e.g., borosilicate), silicon dioxide (SiO2), aluminum oxide (Al2O3), titanium oxide (TiO2), graphite, and mixtures of two or more of these. In addition, one or more other layers, such as colored layers, may be present.

[0108]

[0107] The non-spherical magnetic or magnetisable pigment particles described herein may be surface treated to protect against any degradation that may occur in the radiation curable coating composition and / or to facilitate incorporation into the radiation curable coating composition, typically with the use of corrosion inhibitors and / or wetting agents.

[0109]

[0108] The substrates described herein are preferably selected from the group consisting of paper or cellulose, paper-containing materials, glass, metals, ceramics, plastics, and other fibrous materials such as polymers, metallized plastics or polymers, composites, and mixtures or combinations thereof. Representative paper, paper-like, or other fibrous materials are composed of various fibers, including, but not limited to, abaca, cotton, hemp, wood pulp, and mixtures thereof. As is known to those skilled in the art, cotton and cotton / hemp blends are preferred for banknotes, while wood pulp is commonly used for security documents other than banknotes. Representative examples of plastics and polymers include polyolefins such as polyethylene (PE) and polypropylene (PP), polyamides, polyesters such as poly(ethylene terephthalate) (PET), poly(1,4-butylene terephthalate) (PBT), poly(ethylene 2,6-naphthoate) (PEN), and polyvinyl chloride (PVC). Spunbond olefin fibers, such as those sold under the trademark Tyvek®, can also be used as substrates. Representative examples of metallized plastics or polymers include the above-mentioned plastic or polymeric materials having a metal disposed continuously or discontinuously on the surface. Representative examples of metals include, but are not limited to, aluminum (Al), chromium (Cr), copper (Cu), gold (Au), iron (Fe), nickel (Ni), silver (Ag), combinations thereof, or alloys of two or more of these metals. The metallization of the above-mentioned plastic or polymeric materials may be performed by an electrodeposition process, a high vacuum coating process, or a sputtering process. Representative examples of composites include, but are not limited to, multi-layered structures or laminates of paper and at least one of the above-mentioned plastic or polymeric materials, as well as plastic and / or polymeric fibers incorporated into the above-mentioned paper-like or fibrous materials. Of course, the substrate may also include other additives known to those skilled in the art, such as sizing agents, bleaching agents, processing aids, reinforcing or wet-strength agents, etc. The substrates described herein may be provided in the form of a web (e.g., a continuous sheet of the above-mentioned material) or in the form of a sheet.When an optical effect layer (OEL) produced according to the present invention is on a security document, the substrate may comprise a printed, coated, laser marked or laser drilled indicia, watermark, security thread, fiber, planchette, luminescent compound, window, foil, decal, and combinations of two or more thereof, for the purpose of providing a higher level of security and resistance to counterfeiting and illegal duplication of the security document. The substrate may also comprise one or more marker substances or traceable additives and / or machine readable substances (e.g., luminescent substances, UV / visible / IR absorbing substances, magnetic substances, and combinations thereof) for the same purpose of providing a higher level of security and resistance to counterfeiting and illegal duplication of the security document.

[0110]

[0109] The shape of the coating layer (x10) of the optical effect layer (OEL) described herein may be continuous or discontinuous. According to one embodiment, the shape of the coating layer (x10) represents one or more indicia, dots, and / or lines. The shape of the coating layer (x10) may consist of lines, dots, and / or indicia separated from each other by empty areas.

[0111]

[0110] The optical effect layers (OELs) described herein may be applied directly onto a substrate to remain permanently (e.g., for banknote applications). Alternatively, the OEL may be applied onto a temporary substrate for production, with the OEL being removed at a later time. This may facilitate, for example, production of the OEL, especially if the binder material remains in a fluid state. The coating composition may then be at least partially cured to produce the OEL, and the temporary substrate may be removed from the OEL.

[0112] Alternatively, an adhesive layer may be present on the OEL or on the substrate carrying the OEL, either on the side of the substrate opposite to that on which the OEL is applied, or on the same side as the OEL. Thus, the OEL or the substrate may be coated with an adhesive layer. Such an article may be adapted to be attached to any kind of document or other article without machinery or laborious processes such as printing. Alternatively, the substrate described herein with the OEL described herein may be in the form of a transfer foil that can be applied to a document or article in a separate transfer step. For this purpose, the substrate is provided with a release coating on which the OEL is produced as described herein. On the OEL thus produced, one or more adhesive layers may be applied.

[0113]

[0112] Also described herein is a substrate provided with two or more, ie, two, three, four, etc., optical effect layers (OELs) obtained by the processes described herein.

[0114] Also described herein are articles, in particular security documents, decorative elements or objects, that are provided with an optical effect layer (OEL) produced according to the present invention. These articles, in particular security documents, decorative elements or objects, may comprise two or more (e.g., two, three, etc.) OELs produced according to the present invention.

[0115]

[0114] As mentioned above, the optical effect layers (OELs) produced according to the present invention may be adapted for use for decorative purposes and for security document protection and authentication. Representative examples of decorative elements or objects include, but are not limited to, luxury goods, cosmetic packaging, automotive parts, electronic / appliance products, furniture, and nail lacquers.

[0116]

[0115] Security documents include, but are not limited to, value documents and value goods. Representative examples of value documents include banknotes, certificates, tickets, cheques, vouchers, revenue and tax stamps, contracts, etc., identity documents such as passports, identity cards, visas, driver's licenses, bank cards, credit cards, transaction cards, access documents or cards, admission tickets, public transport tickets or certificates, etc., with banknotes, identity documents, entitlement documents, driver's licenses, and credit cards being preferred, but not limited to them. The term "value commercial good" refers to packaging materials, especially cosmetics, dietary supplements, medicines, alcohol, tobacco products, beverages or foodstuffs, electrical / electronic products, textiles or jewellery, i.e. goods whose contents should be guaranteed by protection against counterfeiting and / or illegal copying, such as genuine medicines. Examples of these packaging materials include, but are not limited to, labels and stickers, such as certified brand labels, tamper-proof labels, etc. It should be noted that the disclosed substrates, documents of value, and items of value are presented for illustrative purposes only, without limiting the scope of the present invention.

[0117]

[0116] Alternatively, the optical effect layer (OEL) may be produced on a supplementary substrate, such as a security thread, security stripe, foil, decal, window, or label, and then transferred to the security document in a separate step.

[0118]

[0117] Those skilled in the art may conceive of several modifications to the specific embodiments described above without departing from the spirit of the present invention. Such modifications are included in the present invention.

[0119]

[0118] Additionally, all references cited throughout this specification are hereby incorporated by reference in their entirety. EXAMPLES

[0120]

[0119] Figures 5 to 7 AThe magnetic assembly (x00) shown in Figure 8 was used to orient the non-spherical, specifically platelet-shaped, optically variable magnetic pigment particles in a coating layer (x10) of a UV-curable screen printing ink as described in Table 1 to produce the optical effect layer (OEL) shown in Figures 8B-1 to 8B-3. The UV-curable screen printing ink was applied to a black commercial paper (Gascogne Laminates M-cote 120) (x20) by manually screen printing using a T90 screen to construct a square-shaped coating layer (x10) approximately 20 μm thick and measuring 35 mm x 35 mm. The magnetic orientation pattern of the platelet-shaped optically variable magnetic pigment particles thus obtained was then partially simultaneously with the orientation step (i.e. while the substrate (x20) with the coating layer (x10) of the UV-curable screen printing ink was still in the magnetic field of the magnetic assembly (x00)) by a Phoseon UV-LED lamp (FireFlex type, 50×75 mm, 395 nm, 8 W / cm 2 ) was used to fix the layer containing the pigment particles by exposing it to a UV cure for approximately 0.5 seconds.

[0121] [Table 1]

[0122] Comparative Example 1 (FIGS. 5A to 5C and FIG. 8B-1) 5A-5C show a magnetic assembly (500) used to fabricate the optical effect layer (OEL) of Comparative Example 1 on a substrate (520). The magnetic assembly (500) was configured to receive the substrate (520) in an orientation parallel to the first plane (P).

[0123]

[0121] The magnetic assembly (500) includes 100 first rod-shaped dipole magnets (531) embedded in a first square-shaped support matrix (532). 1~100and a second magnetic field generating device (540) having a second dipole magnet (541) embedded in a second square-shaped support matrix (542), the second magnetic field generating device (540) being disposed below the first magnetic field generating device (530) and between a substrate (520) having a coating layer (510) and the second magnetic field generating device (540). The first magnetic field generating device (530) and the second magnetic field generating device (540) are essentially centered with respect to each other.

[0124]

[0122] The first magnetic field generating device (530) has ten parallel straight lines α i (α 1~10 ) and 10 parallel straight lines β j (β 1~10 100 first rod-shaped dipole magnets (531 1~100 ), and a straight line α i (α 1~10 ) are parallel to each other and are on a straight line β j (β 1~10 ) are parallel to each other, and the straight line α i is the line β j The 10 straight lines α i (α 1~10 ) are equally spaced, and adjacent lines are separated by a distance (A7) of 2.5 mm. i (α 1~10 ) includes 10 first dipole magnets, so that the total number of first dipole magnets is 100 (531 1~100 ) The 10 straight lines β j (β 1~10 ) are equally spaced, and adjacent lines are separated by a distance (A6) of 2.5 mm. i (α 1~10 ) and each line β j (β 1~10 ) the distance between two adjacent first rod-shaped dipole magnets was set to 0.5 mm.

[0125]

[0123] 100 first dipole magnets (5311~100 The 100 first dipole magnets (531 1~100 ) are magnetized in the direction of their length (A5), and the SN magnetic axis is perpendicular to the surface of the substrate (520). i (α 1~10 ) and each line β j (β 1~10 ), as shown by the S→N arrows in FIG. 5A, the N pole of each first rod-shaped dipole magnet faces each of the adjacent magnets (531 1~100 ) facing in the opposite direction to the north pole of the 100 first dipole magnets (531 1~100 ) are arranged so that the NS polarities of each magnet alternate, i.e., the straight line α i (α 1~10 ) and line β j (β 1~10 ) (and along the A1 and A2 directions) were arranged in a 10×10 array such that the SN magnetic field directions along the A1 and A2 directions were opposite.

[0126]

[0124] The first square support matrix (532) of the first magnetic field generating device (530) has dimensions of 50 mm (A1) x 50 mm (A2) x 3 mm (A3), is made of polyoxymethylene (POM), and holds 100 first dipole magnets (531). 1~100 100 recesses for holding the 100 first dipole magnets (531), 1~100 ) so that the 100 first dipole magnets (531 1~100 ) was flush with the top surface of the first square support matrix (532).

[0127]

[0125] The second dipole magnets (541) of the second magnetic field generating device (540) were square dipole magnets with dimensions of 30 mm (B4) x 30 mm (B5) x 4 mm (B3) and made of NdFeB N30. The second dipole magnets (541) were arranged such that their S-N magnetic axes were substantially parallel to the substrate (520) and were aligned with the 100 first dipole magnets (531) of the first magnetic field generating device (530). 1~100 The second magnetic field generator (540) had its vector sum H (corresponding to the magnetic axis of the second dipole magnet (541)) substantially parallel to the substrate (520).

[0128] As shown in FIG. 5A, each straight line α i (α 1~9 The vector sum H of the first magnetic field generating device (540) and the second magnetic field generating device (541) is set to an angle of 0° (i.e., the straight line α i (α 1~10 ) is assumed to be parallel to vector H.

[0129]

[0127] The second square support matrix (542) of the second magnetic field generating device (540) has dimensions of 50 mm (B1) x 50 mm (B2) x 10 mm (B3), is made of polyoxymethylene (POM) and has a recess / hole for holding the second dipole magnet (541), said recess / hole having the same shape and dimensions as the second dipole magnet (541) (i.e., 30 mm (B4) x 30 mm (B5) x 4 mm (B3)) such that the top surface of the second dipole magnet (541) is flush with the top surface of the second square support matrix (542).

[0130]

[0128] The upper surface of the first square-shaped support matrix (532) of the first magnetic field generating device (530) (100 first dipole magnets (531) 1~100The distance (h1) between the top surface of the second dipole magnet (541) of the second magnetic field generator (540) and the surface of the substrate (520) facing the corresponding magnetic assembly (500) was set to 2 mm. The distance (h2) between the top surface of the second dipole magnet (541) of the second magnetic field generator (540) and the bottom surface of the square support matrix (532) of the first magnetic field generator (530) was set to 0 mm. That is, the first magnetic field generator (530) and the second magnetic field generator (540) were in direct contact with each other.

[0131]

[0129] Figure 8B-1 shows the resultant OEL produced by the magnetic assembly (500) shown in Figures 5A-5C at various viewing angles with the substrate (520) tilted from -20° to +20°. The OEL thus obtained gives the optical impression of multiple dark spots and multiple bright spots moving, appearing and / or disappearing in only one direction (vertical) when the substrate carrying the OEL is tilted about two perpendicular axes, the horizontal / horizontal axis and the vertical / vertical axis (no change when the substrate is tilted about the horizontal / horizontal axis).

[0132] Working Example 1

[0130] Figures 6A-6B show a magnetic assembly (600) used to fabricate the optical effect layer (OEL) of Comparative Example 1 on a substrate (620). The magnetic assembly (600) was configured to receive the substrate (620) in an orientation parallel to a first plane (P).

[0133] The magnetic assembly (600) includes 100 first rod-shaped dipole magnets (631) embedded in a first square-shaped support matrix (632). 1~100and a second magnetic field generating device (640) having a second dipole magnet (641) embedded in a second square-shaped support matrix (642), the second magnetic field generating device (640) being disposed below the first magnetic field generating device (630) and between a substrate (620) having a coating layer (610) and the second magnetic field generating device (640). The first magnetic field generating device (630) and the second magnetic field generating device (640) are essentially centered with respect to each other.

[0134]

[0132] The first magnetic field generating device (630) was the same as that described with respect to Comparative Example C1.

[0135]

[0133] The second dipole magnet (641) of the second magnetic field generator (640) was a square dipole magnet with dimensions of 30 mm (B4) x 30 mm (B5) x 4 mm (B3) and made of NdFeB N52. The second dipole magnet (641) had its SN magnetic axis substantially parallel to the substrate (620). The second magnetic field generator (640) had its vector sum H (corresponding to the magnetic axis of the only second dipole magnet (641)) substantially parallel to the substrate (620).

[0136] As shown in FIG. 6A, each straight line α i (α 1~10 ) and a second magnetic field generating device ( 6 The vector sum H of 40) is assumed to form an angle γ of 45°.

[0137]

[0135] The second square support matrix (642) of the second magnetic field generating device (640) has dimensions of 50 mm (B1) x 50 mm (B2) x 4 mm (B3), is made of polyoxymethylene (POM) and has a recess / hole for holding the second dipole magnet (641), said recess / hole having the same shape and dimensions as the second dipole magnet (641) (i.e. 30 mm (B4) x 30 mm (B5) x 4 mm (B3)) such that the top surface of the second dipole magnet (641) is flush with the top surface of the second square support matrix (642).

[0138]

[0136] The upper surface of the first square-shaped support matrix (632) of the first magnetic field generating device (630) (41 first dipole magnets 631 1~41 The distance (h1) between the top surface of the second dipole magnet (641) of the second magnetic field generator (640) and the surface of the substrate (620) facing the corresponding magnetic assembly (600) was set to 1.5 mm. The distance (h2) between the top surface of the second dipole magnet (641) of the second magnetic field generator (640) and the bottom surface of the square support matrix (632) of the first magnetic field generator (630) was set to 0 mm. That is, the first magnetic field generator (630) and the second magnetic field generator (640) were in direct contact with each other.

[0139]

[0137] Figure 8B-2 shows the resultant OEL produced by the magnetic assembly (600) shown in Figures 6A-6B at various viewing angles with the substrate (620) tilted from -20° to +20°. The OEL thus obtained gives the optical impression of multiple dark spots and multiple bright spots moving, appearing and / or disappearing diagonally with respect to the tilt-tilt and tilt-tilt directions when the substrate carrying the OEL is tilted about two perpendicular axes, i.e., the horizontal / transverse axis and the vertical / vertical axis.

[0140] Working Example 2

[0138] Example 2 The magnetic assembly (700) used to fabricate an optical effect layer (OEL) on a substrate (720) is shown in FIG. AThe magnetic assembly (700) was configured to receive a substrate (720) in an orientation parallel to a first plane (P).

[0141]

[0139] The magnetic assembly (700) includes 100 first rod-shaped dipole magnets (731) embedded in a first square-shaped support matrix (732). 1~100 ) and two second dipole magnets (7411, 7412) embedded in a second square-shaped support matrix (742). -2 and a second magnetic field generator (740) comprising a first second dipole magnet (7411) and a second second dipole magnet (7412), the first second dipole magnet (7411) being disposed above the second second dipole magnet (7412), the second magnetic field generator (740) being disposed below the first magnetic field generator (730), and the first magnetic field generator (730) being disposed between the substrate (720) having the coating layer (710) and the second magnetic field generator (740). The first magnetic field generator (730) and the second magnetic field generator (740) are essentially centered with each other.

[0142]

[0140] The first magnetic field generating device (730) was the same as that described with respect to Comparative Example C1.

[0143]

[0141] The second magnetic field generating device (740) includes two second dipole magnets (7411, 7412), both of which are square dipole magnets. -2 ), the first second dipole magnet (7411) had dimensions of 30 mm (B4) x 30 mm (B5) x 2 mm, the second second dipole magnet (7412) had dimensions of 30 mm (B4) x 30 mm (B5) x 3 mm, and both were made of NdFeB N52. These two second dipole magnets (7411, 741 -2 ) was assumed to have the SN magnetic axis substantially parallel to the substrate (720). A As shown, the magnetic axis of the first secondary dipole magnet (7411) was perpendicular to the magnetic axis of the second secondary dipole magnet (7412).

[0144]

[0142] The second magnetic field generating device (740) includes two second dipole magnets (7411, 741 -2 ) with recesses / holes to hold two second dipole magnets (7411, 741 -2 3. The same second square support matrix (742) as used in Comparative Example C1, except that dimension B3 was 5 mm (i.e., the depth of the recess) such that the first second dipole magnet (7411) had the same shape and dimensions as the first second dipole magnet (7411) (i.e., 30 mm (B4) x 30 mm (B5) x 5 mm (B3 = 2 + 3)), such that the top surface of the first second dipole magnet (7411) was flush with the top surface of the second square support matrix (742) and the two second dipole magnets (7411, 741 -2 ) were stacked together, centered and in direct contact with each other. The second magnetic field generator (740) was such that the vector sum H (the result of the sum of the magnetic axes of the first secondary dipole magnet (8411) and the second secondary dipole magnet (8412)) was substantially parallel to the substrate (720).

[0145]

[0143] Figure 7A As shown in the figure, each straight line α i (α 1~10 ), the vector sum H of the line and the second magnetic field generator (740) forms an angle γ of 45°.

[0146]

[0144] The top surface of the first square-shaped support matrix (732) of the first magnetic field generating device (730) (100 first dipole magnets ( 7 31 1~100 The distance (h1) between the top surface of the second dipole magnet (741) of the second magnetic field generator (740) and the surface of the substrate (720) facing the magnetic assembly (700) was approximately 2 mm. The distance (h2) between the top surface of the second dipole magnet (741) of the second magnetic field generator (740) and the bottom surface of the square support matrix (732) of the first magnetic field generator (730) was 0 mm. That is, the first magnetic field generator (730) and the second magnetic field generator (640) were in direct contact with each other.

[0147]

[0145] FIG. 8B-3 shows theA 3 shows a resultant OEL produced by the magnetic assembly (700) shown in FIG. The OEL thus obtained gives the optical impression of multiple dark spots and multiple bright spots moving, appearing, and / or disappearing diagonally with respect to the tilt-tilt and tilt-tilt directions when the substrate carrying the OEL is tilted about two perpendicular axes, i.e., the horizontal / transverse axis and the vertical / vertical axis.

Claims

1. A magnetic assembly (x00) for producing an optical effect layer (OEL) on a substrate (x20), the magnetic assembly (x00) being configured to receive the substrate (x20) above a first plane (P) in an orientation at least partially parallel to the first plane (P), a) a first magnetic field generating device (x30) comprising at least four first dipole magnets (x31) oriented with their magnetic axes substantially perpendicular to said first plane (P); Each of the first dipole magnets (x31) has at least two substantially parallel straight lines α ｉ (i=1, 2, ...) and at least two substantially parallel straight lines β ｊ (j=1, 2, . . . ), and the straight line α ｉ and β ｊ forms a lattice, At least two first dipole magnets (x31) are arranged along the straight line α ｉ and at least two other first dipole magnets (x31) are disposed on one of the straight lines α ｉ and disposed on another one of the Each straight line α ｉ Above and each straight line β ｊ On the top, the N poles of adjacent first rod-shaped dipole magnets (x31) face in opposite directions, The first dipole magnet (x31) of the first magnetic field generating device (x30) is partially or completely embedded in a first support matrix (x32); A first magnetic field generating device (x30); b) a second magnetic field generating device (x40) comprising one or more second dipole magnets (x41) with their magnetic axes oriented substantially parallel to said first plane (P) and embedded partly or completely in a second support matrix (x42); The second magnetic field generating device (x40) is disposed below the first magnetic field generating device (x30), Each straight line α ｉ and a vector sum H of the magnetic axes of the one or more second dipole magnets (x41) are substantially non-parallel and substantially non-perpendicular to each other and form a fixed angle γ; A second magnetic field generating device (x40); A magnetic assembly (x00) comprising:

2. Each straight line α ｉ and a vector sum H of the magnetic axes of the one or more second dipole magnets (x41) form an angle γ in the range of 20° to 70°, in the range of 110° to 160°, in the range of 200° to 250°, or in the range of 290° to 340°.

3. The first magnetic field generating device (x30) comprises at least six first dipole magnets (x31), and the grid is aligned along the substantially parallel straight lines α ｉ At least three of the substantially parallel straight lines β ｉ At least two of the following: At least two first dipole magnets (x31) are arranged along the straight line α ｉ and at least two other first dipole magnets (x31) are disposed on one of the straight lines α ｉ and at least two other first dipole magnets (x31) are disposed on another one of the straight lines α ｉ The magnetic assembly (x00) according to claim 1 or 2, disposed on yet another one of the magnetic poles.

4. The first magnetic field generating device (x30) comprises at least nine first dipole magnets (x31), and the grid is arranged to be parallel to the substantially parallel straight lines α ｉ At least three of the substantially parallel straight lines β ｉ At least three of the following: At least three first dipole magnets (x31) are arranged along the straight line α ｉ At least three first dipole magnets (x31) are arranged on one of the straight lines α ｉ and at least three other first dipole magnets (x31) are arranged on another one of the straight lines α ｉ The magnetic assembly (x00) according to any one of claims 1 to 3, disposed on yet another one of the magnetic poles.

5. Each straight line α ｉ And / or each straight line β ｊ A magnetic assembly (x00) according to any one of claims 1 to 4, wherein adjacent first dipole magnets (x31) are spaced apart from each other.

6. A magnetic assembly (x00) as described in claim 5, wherein the adjacent first dipole magnets (x31) are separated from each other by the same distance.

7. A magnetic assembly (x00) according to any one of claims 1 to 6, wherein the second magnetic field generating device (x40) comprises two or more second dipole magnets (x41), each oriented with its magnetic axis substantially parallel to the first plane (P).

8. 8. The magnetic assembly (x00) of claim 7, wherein the second magnetic field generating device (x40) comprises two second dipole magnets (x41), one of the two second dipole magnets being disposed above the other of the two second dipole magnets (x41), and the north poles of each of the two second dipole magnets (x41) point in different directions.

9. Use of a magnetic assembly (x00) according to any one of claims 1 to 8 for producing an optical effect layer (OEL) on a substrate.

10. A printing device comprising a rotating magnetic cylinder having at least one of the magnetic assemblies (x00) according to any one of claims 1 to 8, or a printing device comprising a flatbed printing unit having at least one of the magnetic assemblies (x00) according to any one of claims 1 to 8.

11. A process for producing an optical effect layer (OEL) on a substrate (x20), comprising: i) applying a radiation curable coating composition comprising a plurality of non-spherical magnetic or magnetisable pigment particles to a surface of a substrate (x20) in a first state so as to form a coating layer (x10); ii) exposing said radiation curable coating composition to a magnetic field of a stationary magnetic assembly (x00) according to any one of claims 1 to 8 so as to orient at least a portion of said non-spherical magnetic or magnetisable pigment particles; iii) at least partially curing said radiation curable coating composition of step ii) to a second state so as to fix said non-spherical magnetic or magnetisable pigment particles in their adopted positions and orientations; The process includes:

12. 12. The process of claim 11, wherein said step iii) is carried out by UV-Visible radiation curing, said step iii) being carried out partially simultaneously with said step ii).

13. 13. The process according to claim 11 or 12, wherein at least a part of said plurality of non-spherical magnetic or magnetisable pigment particles is constituted by non-spherical optically variable magnetic or magnetisable pigment particles.

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

15. 15. The process according to any one of claims 11 to 14, further comprising the step of exposing said coating layer (x10) to a dynamic magnetic field of an apparatus so as to biaxially orient at least a portion of said non-spherical magnetic or magnetisable pigment particles, said step occurring before or at least partly simultaneously with said step ii) and before said step iii).

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