Magnetic assembly and process for generating an optical effect layer comprising aligned non-spherical magnetic or magnetizable pigment particles

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 the Invention

[0001]

[01] The present invention relates to the field of protection of valuable documents and valuable or branded goods against forgery and illegal reproduction. In particular, the present invention relates to a process for generating an optically effective layer (OEL) exhibiting a dynamically visual appearance and the optically effective layer obtained thereby, as well as the use of said OEL as an anti-counterfeiting means on documents and articles. Background of the Invention

[0002]

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

[0003]

[03] The security features of security documents and articles can be classified into "secret" and "public" security features. Protection by secret security features relies on the concept that such features are hidden from the human senses and usually require special equipment and knowledge for detection. On the other hand, "public" security features are easily detectable by the human senses alone. Such features are detectable by visualization and / or touch while still being difficult to generate and / or copy. However, the effectiveness of public security features largely depends on their easy recognition as security features. This is because if the user is aware of the existence and nature of such a security feature, they have no choice but to actually perform a security check based on that security feature.

[0004]

[04] Regarding coatings or layers containing aligned magnetic or magnetizable pigment particles, they 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. According to the magnetic or magnetizable pigment particles in the coating, by applying a corresponding magnetic field, after locally aligning the magnetic or magnetizable pigment particles in the uncured coating and then curing them to fix the particles in their respective positions and orientations, magnetic induction images, designs, and / or patterns can be generated. Thereby, a specific optical effect, namely a fixed magnetic induction image, design, or pattern with high resistance to forgery, can be obtained. Security elements based on aligned magnetic or magnetizable pigment particles can be generated only when both a magnetic or magnetizable pigment particle or a corresponding ink or coating composition containing such particles and a specific technique used to cure the ink or coating composition after application of the ink or coating composition and alignment of the pigment particles in the applied ink or coating composition are available.

[0005]

[05] When viewing conditions such as the viewing angle change and the visual appearance of the security feature changes, a remarkable optical effect can be realized. As an example, there is a so-called "rolling bar" effect as disclosed in U.S. Patent Application Publication No. 2005 / 0106367. The "rolling bar" effect is based on the alignment of pigment particles that reproduce a curved surface throughout the coating. To the observer, specular reflection regions that move away from or towards the observer according to the inclination of the image can be seen. This effect is currently used in many security elements on banknotes, such as the "5" and "10" on the 5-euro banknote and the 10-euro banknote respectively. Other examples of dynamic optical effects that give the impression of a loop-shaped body such as a ring are those disclosed in International Publication No. 2014 / 108403 A2 and International Publication No. 2014 / 108404 A2.

[0006]

[06] European Patent No. 2 846 932 B1 discloses, in addition to an optical effect layer (OEL), an apparatus and a method for generating the OEL. The disclosed OEL gives an optical impression of a pattern consisting of bright and dark regions that move in the same direction as the tilt direction when the substrate provided with the OEL is tilted.

[0007]

[07] There is still a need for a magnetic assembly and a process for generating an optical effect layer (OEL) based on magnetically oriented magnetic or magnetizable pigment particles in an ink or a coating composition, said magnetic assembly and process being reliable, easy to implement and functional in high-speed production while exhibiting a dynamic effect and enabling the generation of an OEL that is difficult to produce on a large scale with equipment available to counterfeiters. SUMMARY OF THE INVENTION

[0008]

[08] Accordingly, an object of the present invention is a magnetic assembly (x00) for generating 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 generating device (x30) comprising at least four first dipole magnets (x31) that are spaced apart from each other and oriented such that their N poles face in the same direction and their magnetic axes are substantially parallel to the first plane (P), each of the first dipole magnets (x31) being located at the intersection of 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,...), the straight lines α i and β j forming a grid, at least two of the first dipole magnets (x31) being arranged on one of the straight lines α i and at least two other first dipole magnets (x31) being arranged on another one of the straight lines α i (i = 1, 2,...), the magnetic axes of the first dipole magnets (x31) being substantially parallel to the straight lines αi oriented substantially parallel to, wherein the first dipole magnet (x31) of the first magnetic field generating device (x30) is partially or entirely embedded in the 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) oriented such that their magnetic axes are substantially parallel to the first plane (P) and partially or entirely embedded in the second support matrix (x42), wherein the 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), and providing a magnetic assembly (x00).

[0009]

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

[0010]

[0010] Also described herein is a printing apparatus comprising a rotary magnetic cylinder comprising at least one of the magnetic assemblies (x00) described herein, or a printing apparatus comprising a flatbed printing unit comprising at least one of the magnetic assemblies (x00) described herein.

[0011]

[0011] Also described herein is a process for generating the optical effect layer (OEL) described herein on a substrate (x20) described herein, comprising: i) applying to the surface of the substrate (x20) a radiation - curable coating composition in a first state such that it forms a coating layer (x10) and contains a plurality of non - spherical magnetic or magnetizable pigment particles, Exposing a radiation-curable coating composition to the magnetic field of the fixed magnetic assembly (x00) 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 magnetizable pigment particles in their respective adopted positions and orientations; A process is described which comprises.

[0012]

[0012] Also described herein is an optical effect layer (OEL) produced by the process described herein.

[0013]

[0013] Also described herein is a method of manufacturing a security document or a decorative element or object, comprising: a) providing a security document or a decorative element or object; and b) providing an optical effect layer (OEL) as described herein, in particular an optical effect layer obtainable by the process described herein, so as to be included in the security document or the decorative element or object.

Brief Description of the Drawings

[0014]

Figure 1A

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Figure 6A

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Figure 8

Figure 9A

Figure 9B-1

Figure 9B-2

Figure 9B-3

[0015] Definition

[0014] The following definitions apply to the meanings of the terms used in this specification and the terms recited in the claims.

[0016]

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

[0017]

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

[0018]

[0017] The terms "substantially parallel" / "substantially non-parallel" represent that the deviation from the parallel alignment is 10° or less, and the terms "substantially perpendicular" / "substantially non-perpendicular" represent that the deviation from the perpendicular alignment is 10° or less.

[0019]

[0018] In this specification, the term "and / or" means that both or only one of the elements connected by this term exist. For example, "A and / or B" is meant to mean "only A, only B, or both A and B". In the case of "only A", this term also covers the possibility that B does not exist, that is, the possibility of "only A and not B".

[0020] 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 also contain compounds other than A. However, since the term "comprising" encompasses, as a specific embodiment thereof, the more restrictive meanings of "consisting essentially of" and "consisting of", for example, a "composition containing A, B, and optionally C" may (essentially) consist of A and B, or may (essentially) consist of A, B, and C.

[0021]

[0020] The term "coating composition" represents any composition that can form a coating as described herein, particularly an optical effect layer (OEL), on a solid substrate and can be preferably and non-exclusively applied by a printing method. The coating composition described herein contains 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 containing 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 arrested (fixed / arrested) at predetermined positions and orientations within the binder.

[0023]

[0022] In the context of the present disclosure, "pigment particles" represent particulate substances that are insoluble in both inks and coating compositions and impart specific spectral properties (e.g., opacity, color, or color change) to the coating composition.

[0024]

[0023] In the context of the present invention, the term "magnetic axis" connects the N pole (indicated by "N" and / or dark gray) and the S pole (indicated by "S" and / or light gray) of a magnet, and represents a unit vector directed from the S pole to the N pole (page 463 of Handbook of Physics, Springer 2002). In FIGS. 6A, 7A, and 8, the magnetic axis of the second dipole magnet is indicated by an arrow having a terminal corresponding to the N pole.

[0025]

[0024] In the context of the present invention, the term "vector sum" refers to a vector that is the result of adding two or more magnetic axes in accordance with the laws of vector geometry.

[0026]

[0025] As used herein, the term "at least" defines an amount greater than or equal to a determined quantity; for example, "at least one" means one, two, three, or the like.

[0027]

[0026] The term "security document" refers to a document that is protected against forgery or fraud by at least one security feature. Examples of security documents include, but are not limited to, currency, valuable documents, identity documents, and the like.

[0028]

[0027] The term "security feature" refers to a public or secret image, pattern, or graphic element that can be used for authenticating a document or article having the same.

[0029]

[0028] When referring herein to "preferred" embodiments / features, combinations of these "preferred" embodiments / features are also considered to be disclosed insofar as the combination is technically meaningful.

[0030]

[0029] The present invention provides a magnetic assembly (x00) for generating an optical effect layer (OEL) comprising a plurality of non-randomly oriented non-spherical magnetic or magnetizable pigment particles dispersed within a solidifying / hardening material, a process using the magnetic assembly (x00), and the optical effect layer (OEL) obtained thereby. Due to the orientation pattern of the magnetic or magnetizable pigment particles, the optical effect layer OEL described herein not only causes a plurality of dark spots and a plurality of bright spots to move, appear, and / or disappear in a diagonal direction when the substrate having the OEL is tilted about a vertical / longitudinal axis, but also gives an optical impression of moving, appearing, and / or disappearing in a diagonal direction when the substrate having the OEL is tilted about a horizontal / transverse axis. In other words, the optical effect layer OEL described herein gives an optical impression of a plurality of dark spots and a plurality of bright spots moving, appearing, and / or disappearing in two directions (vertical and horizontal) when the substrate having the OEL is tilted about two vertical axes, namely the horizontal / transverse axis and the vertical / longitudinal axis.

[0031]

[0030] According to the magnetic assembly (x00) described herein, an OEL can be generated on the substrate (x20) described herein, and the magnetic assembly (x00) is used to generate the OEL described herein by the orientation of non-spherical magnetic or magnetizable pigment particles. The magnetic assembly (x00) described herein is based on the interaction of at least a) the first magnetic field generating device (x30) described herein and b) the second magnetic field generating device (x40) described herein, which have mutually twisted magnetic axes. That is, these magnetic axes are substantially non-parallel and substantially non-perpendicular to each other.

[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 generating the optical effect layer (OEL) described herein, the substrate (x20) having the coating layer (x10) containing non-spherical magnetic or magnetizable pigment particles is disposed above the first magnetic field generating device (x30), and the first magnetic field generating device (x30) is disposed above the second magnetic field generating device (x40). The first magnetic field generating device (x30) and the second magnetic field generating device (x40) preferably have substantially coincident centers. That is, the first magnetic field generating device (x30) and the second magnetic field generating device (x40) described herein are preferably stacked and coaxially arranged.

[0033]

[0032] The magnetic assembly (x00) described herein includes the first magnetic field generating device (x30) described herein, and the first magnetic field generating device (x30) includes four or more first dipole magnets (x31) partially or entirely embedded in the first support matrix (x32) described herein. For example, as shown in FIGS. 1 to 8, each of the first dipole magnets (x31), in particular, each center (C x31 ) is disposed at the intersection of a grid, and the grid includes at least two substantially parallel straight lines α i and at least two substantially parallel straight lines β j (i is 1, 2, etc., j is 1, 2, etc.). The grid described herein corresponds to a pattern consisting of straight lines α i and β j that form cells having a square, rectangular, or parallelogram shape by intersecting each other. According to one embodiment, for example, as shown in FIGS. 1 to 5, each of the first dipole magnets (x31), in particular, each center (C x31 ) is disposed at the intersection of a grid, and each intersection of the grid includes the first dipole magnet (x31). According to another embodiment, for example, as shown in FIGS. 6A, 7A, and 8, each of the first dipole magnets (x31), in particular, each center (C x31) is arranged at the intersection of the grid, but some of the intersections of the grid do not include the first dipole magnet (x31).

[0034]

[0033] At least two first dipole magnets (x31), in particular, each center (C x31 ) is arranged on one of the substantially parallel straight lines α i Among them, at least two other first dipole magnets (x31), in particular, each center (C x31 ) is arranged on another one of the substantially parallel straight lines α i That is to say, there are at least two first dipole magnets (x31) on each substantially parallel straight line α i .

[0035]

[0034] The first dipole magnet (x31), in particular, each center (C x31 ) is arranged at the intersection of the grid including at least two substantially parallel straight lines α i described in this specification and at least two substantially parallel straight lines β j . Since the straight line α i intersects the straight line β j , the first dipole magnet (x31), in particular, each center (C x31 ) is also arranged on the straight line β j .

[0036]

[0035] In FIGS. 1A and 1B, the first magnetic field generating device (130) includes four first dipole magnets (131 1-1 , 131 1-2 , 131 2-1 , 131 2-2 ) embedded in the first support matrix (132). The first dipole magnets (131 1-1 , 131 1-2 , 131 2-1 , 131 2-2 ) are two substantially parallel straight lines α i (α1, α2) and two substantially parallel straight lines β jIt is disposed at the intersection of a lattice including (β1, β2). In FIGS. 2A and 2B, the first magnetic field generating device (230) includes six first dipole magnets (231 1-1 , 231 1-2 , 231 1-3 , 231 2-1 , 231 2-2 , 231 2-3 ) embedded in the first support matrix (232), and the first dipole magnets (231 1-1 , 231 1-2 , 231 1-3 , 231 2-1 , 231 2-2 , 231 2-3 ) are disposed at the intersections of a lattice including two substantially parallel straight lines α i (α1, α2) and three substantially parallel straight lines β j (β1, β2, β3). In FIGS. 3A and 3B, the first magnetic field generating device (330) includes six first dipole magnets (331 1-1 , 331 1-2 , 331 2-1 , 331 2-2 , 331 3-1 , 331 3-2 ) embedded in the first support matrix (332), and the first dipole magnets (331 1-1 , 331 1-2 , 331 2-1 , 331 2-2 , 331 3-1 , 331 3-2 ) are disposed at the intersections of a lattice including three substantially parallel straight lines α i (α1, α2, α3) and two substantially parallel straight lines β j (β1, β2). In FIGS. 4A and 4B, the first magnetic field generating device (430) includes nine first dipole magnets (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) is provided, 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 ) is disposed at the intersection of a lattice including three substantially parallel straight lines α i (α1, α2, α3) and three substantially parallel straight lines β j (β1, β2, β3).

[0037]

[0036] The substantially parallel straight lines α i are substantially parallel to each other, and the substantially parallel straight lines β j are substantially parallel to each other. According to an embodiment shown in FIGS. 1A, 2A, 3A, and 4A, for example, the straight line α i is substantially perpendicular to the straight line β j . That is, since the angle formed between the straight line α i and the straight line β j is 90°, a lattice including cells having a square or rectangular shape is formed. According to another embodiment shown in FIGS. 1B, 2B, 3B, and 4B, for example, the straight line α i is not substantially perpendicular to the straight line β j . That is, since the angle formed between the straight line α i and the straight line β j is not 90°, a lattice including cells having a parallelogram shape is formed.

[0038]

[0037] According to an embodiment shown in FIGS. 1A and 1B, for example, 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), in particular, each center (C x31 ) is disposed at the intersection of at least two substantially parallel straight lines α i (α1, α2) and at least two substantially parallel straight lines β j (β1, β2), the straight lines α i being substantially parallel to each other, and the straight lines βj are substantially parallel to each other, and the straight line α i and β j form a lattice (i.e., a lattice including two substantially parallel straight lines α i (α1, α2) and two substantially parallel straight lines β j (β1, β2)). At least two first dipole magnets (x31), in particular, each center (C x31 ) is disposed on one of the straight lines α i (α1), and at least two other first dipole magnets (x31) are disposed on another one of the straight lines α i (α2).

[0039]

[0038] According to another embodiment shown in FIGS. 2A and 2B, for example, at least six first dipole magnets (x31) are included in the first magnetic field generating device (x30), and each first dipole magnet (x31), in particular, each center (C x31 ) is disposed at the intersection of at least two substantially parallel straight lines α i (α1, α2) and at least three substantially parallel straight lines β j (β1, β2, β3), and the straight lines α i and β j form a lattice (i.e., a lattice including two substantially parallel straight lines α i (α1, α2) and three substantially parallel straight lines β j (β1, β2)). At least three dipole magnets (x31), in particular, each center (C x31 ) is disposed on one of the straight lines α i (α1), and at least three other first dipole magnets (x31) are disposed on another one of the straight lines α i (α2).

[0040]

[0039] According to another embodiment shown in FIGS. 3A and 3B, for example, at least six first dipole magnets (x31) are included in the first magnetic field generating device (x30), and each first dipole magnet (x31), in particular, each center (C x31 ) is disposed at the intersection of at least three substantially parallel straight lines α i(α1, α2, α3) and at least two substantially parallel straight lines β j are arranged at the intersection point of (β1, β2), and the straight lines α i and β j form a lattice (i.e., a lattice including three substantially parallel straight lines α i (α1, α2, α3) and two substantially parallel straight lines β j (β1, β2)). At least two first dipole magnets (x31), in particular, each center (C x31 ) is disposed on one of the straight lines α i (α1), at least two other first dipole magnets (x31) are disposed on another one of the straight lines α i (α2), and at least two other first dipole magnets (x31) are disposed on yet another one of the straight lines α i (α3).

[0041]

[0040] According to another embodiment shown in FIGS. 4A and 4B, for example, at least nine first dipole magnets (x31) are included in the first magnetic field generating device (x30), and each first dipole magnet (x31), in particular, each center (C x31 ) is arranged at the intersection point of at least three substantially parallel straight lines α i (α1, α2, α3) and at least three substantially parallel straight lines β j (β1, β2, β3), and the straight lines α i and β j form a lattice (i.e., a lattice including three substantially parallel straight lines α i (α1, α2, α3) and three substantially parallel straight lines β j (β1, β2, β3)). At least three first dipole magnets (x31), in particular, each center (C x31 ) is disposed on one of the straight lines α i (α1), at least three other first dipole magnets (x31) are disposed on another one of the straight lines α i (α2), and at least three other first dipole magnets (x31) are disposed on yet another one of the straight lines α i (α3).

[0042]

[0041] When including three or more substantially parallel straight lines α i the distance between adjacent straight lines α i may be the same or different. In FIGS. 3A, 3B, 4A, 4B, and 5, the distances d1 and d2 between adjacent straight lines α i (i.e., 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] When including three or more substantially parallel straight lines β j the distance between adjacent straight lines β j may be the same or different. In FIGS. 2A, 2B, 4A, 4B, and 5, the distances e1 and e2 between adjacent straight lines β j (i.e., 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] The distance between two substantially parallel straight lines α i and the distance between two substantially parallel straight lines β j may be the same or different.

[0045]

[0044] All of the first dipole magnets (x31) of the first magnetic field generating device (x30) described in this specification are oriented such that the N poles face the same direction and the magnetic axes are substantially parallel to the first plane (P) (i.e., when the magnetic assembly (x00) is used in the process described in this specification, the magnetic axes are oriented substantially parallel to the surface of the substrate (x20)). All of the magnetic axes of the first dipole magnets (x31) are oriented substantially parallel to a substantially parallel straight line α i

[0046]

[0045] Each straight line α i and / or each straight line β jAbove, the first dipole magnets (x31) described in this specification are separated from each other. That is, they are not adjacent. Each of the first dipole magnets is separated from its adjacent magnet by a gap, that is, a distance greater than 0.

[0047]

[0046] According to one embodiment, each straight line α i Above, the first dipole magnets (x31) described in this specification are separated from each other. That is, they are not adjacent. Each of the first dipole magnets is separated from its adjacent magnet by a gap, that is, a distance greater than 0, preferably a gap, that is, a distance of approximately 0.1 mm to 10 mm, more preferably a gap, that is, a distance of approximately 0.2 mm to 6 mm. According to one embodiment, each straight line β j Above, the first dipole magnets (x31) described in this specification are separated from each other. That is, they are not adjacent. Each of the first dipole magnets is separated from its adjacent magnet by a gap, that is, a distance greater than 0, preferably a gap, that is, a distance of approximately 0.1 mm to 10 mm, more preferably a gap, that is, a distance of approximately 0.2 mm to 6 mm. According to one embodiment, each straight line α i and each straight line β j Above, the first dipole magnets (x31) described in this specification are separated from each other. That is, they are not adjacent. Each of the first dipole magnets is separated from its adjacent magnet by a gap, that is, a distance greater than 0, and the distance is independently preferably approximately 0.1 mm to 10 mm, and independently more preferably approximately 0.2 mm to 6 mm.

[0048]

[0047] The first dipole magnets (x31) of the first magnetic field generating device (x30) described in this specification may have the same shape, the same dimensions, and may also be composed of the same material.

[0049]

[0048] For example, according to one embodiment shown in FIGS. 1A and 1B, the first magnetic field generating device (x30) described in this specification includes two substantially parallel straight lines α i(α1, α2) and two substantially parallel straight lines β j At least four first bipolar magnets x31 arranged at the intersections of a lattice including (β1, β2), with the N poles facing the same direction and the magnetic axes oriented to be substantially parallel to the first plane (P) (i.e., the surface of the substrate (x20)). i Comprising (x311, x312, ···). At least four first bipolar magnets x31 i (x311, x312, ···) each have their centers (C x31 ) arranged at the intersections of the lattice. The straight line α i (α1, α2) is either substantially perpendicular to the straight line β j (β1, β2) (see FIG. 1A) or not substantially perpendicular to the straight line β j (β1, β2) (see FIG. 1B).

[0050]

[0049] For example, according to an embodiment shown in FIGS. 2A and 2B, the first magnetic field generating device (x30) described herein includes two substantially parallel straight lines α i (α1, α2) and three substantially parallel straight lines β j (β1, β2, β3) and is arranged at the intersections of a lattice, with at least six first bipolar magnets x31 having their N poles facing the same direction and their magnetic axes oriented to be substantially parallel to the first plane (P) (i.e., the surface of the substrate (x20)). i Comprising (x31). At least six first bipolar magnets x31 i (x311, x312, ···) each have their centers (C x31 ) arranged at the intersections of the lattice. The straight line α i (α1, α2) is either substantially perpendicular to the straight line β j (β1, β2, β3) (see FIG. 2A) or not substantially perpendicular to the straight line β j (β1, β2, β3) (see FIG. 2B).

[0051]

[0050] For example, according to an embodiment shown in FIGS. 3A and 3B, the first magnetic field generating device (x30) described herein includes three substantially parallel straight lines α i(α1, α2, α3) and two substantially parallel straight lines β j At least six first dipole magnets x31 arranged at the intersections of a lattice including (β1, β2), with the N poles facing the same direction and the magnetic axes oriented to be substantially parallel to the first plane (P) (i.e., the surface of the substrate (x20)) i Comprising (x31). At least six first dipole magnets x31 i (x311, x312, ···), each of whose centers (C x31 ) is arranged at the intersection of the lattice. The straight line α i (α1, α2, α3) is either substantially perpendicular to the straight line β j (β1, β2) (see Fig. 3A) or not substantially perpendicular to the straight line β j (β1, β2) (see Fig. 3B).

[0052]

[0051] For example, according to an embodiment shown in Figs. 4A and 4B, the first magnetic field generating device (x30) described in this specification includes three substantially parallel straight lines α i (α1, α2, α3) and three substantially parallel straight lines β j (β1, β2, β3) arranged at the intersections of a lattice, with at least nine first dipole magnets x31 whose N poles face the same direction and the magnetic axes are oriented to be substantially parallel to the first plane (P) (i.e., the surface of the substrate (x20)) i Comprising (x31). At least nine first dipole magnets x31 i (x311, x312, ···), each of whose centers (C x31 ) is arranged at the intersection of the lattice. The straight line α i (α1, α2, α3) is either substantially perpendicular to the straight line β j (β1, β2, β3) (see Fig. 4A) or not substantially perpendicular to the straight line β j (β1, β2, β3) (see Fig. 4B).

[0053]

[0052] The first magnetic field generating device (x30) described in this specification may further include one or more third dipole magnets (x33) partially or entirely embedded in the first support matrix (x32), in addition to the first dipole magnet (x31) and the first support matrix (x32) described in this specification. The one or more third bar-shaped dipole magnets (x33) are oriented such that their magnetic axes are substantially parallel to the first plane (P) (i.e., the surface of the substrate (x20)). The one or more third dipole magnets (x33) and the first dipole magnet (x31) have their N poles facing different directions. In the case of an embodiment where the first magnetic field generating device (x30) described in this specification includes two or more third dipole magnets (x33), the two or more third bar-shaped dipole magnets (x33) have their N poles facing the same direction and are oriented such that their magnetic axes are substantially parallel to the first plane (P) (i.e., the surface of the substrate (x20)). The two or more third dipole magnets (x33) and the first dipole magnet (x31) have their N poles facing different directions. According to the embodiment illustrated in FIG. 5, the number of third dipole magnets (x33) is (the number of lines α - 1) × (the number of lines β - 1). That is, in FIG. 5A, it is (2 - 1) × (2 - 1) = 1, and in FIGS. 5B to 5D, it is (3 - 1) × (3 - 1) = 4.

[0054]

[0053] One or more third dipole magnets (x33) are arranged within the lattice described in this specification, which includes two or more substantially parallel lines α i and two or more substantially parallel lines β j and are arranged at positions different from the intersections of the two or more lines α i and β j of the lattice described in this specification. The one or more third dipole magnets (x33) described in this specification may have the same shape, the same dimensions, and may also be composed of the same material. The one or more third dipole magnets (x33) described in this specification may have the same shape, the same dimensions, and may also be composed of the same material as the first dipole magnet (x31).

[0055] According to an embodiment shown in FIG. 5A, the first magnetic field generating device (x30) described herein includes one or more third dipole magnets (x33). According to another embodiment shown in FIGS. 5B to 5D, for example, the first magnetic field generating device (x30) described herein includes four or more third dipole magnets (x33), and the third dipole magnets (x33) are arranged in a lattice in an asymmetric configuration (see FIG. 5B) or a symmetric configuration (see FIGS. 5C and 5D).

[0056]

[0055] According to an embodiment shown in FIGS. 5C and 5D, for example, the first magnetic field generating device (x30) described herein includes four or more third dipole magnets (x33), and at least two third dipole magnets (x33) are arranged on a straight line σ k and at least two other third dipole magnets (x33) are arranged on another straight line σ k and the straight lines σ k are substantially parallel to each other.

[0057]

[0056] According to an embodiment shown in FIGS. 5C and 5D, for example, the first magnetic field generating device (x30) described herein includes at least nine first dipole magnets (x31) and at least four third dipole magnets (x33). The first dipole magnets (x31) are arranged at the intersections of a lattice including three substantially parallel straight lines α i (α1, α2, α3) and three substantially parallel straight lines β j (β1, β2, β3), and the straight lines α i (α1, α2, α3) are substantially perpendicular to the straight lines β j (β1, β2, β3). The third dipole magnets (x33) are arranged at the intersections of another lattice including two substantially parallel straight lines σ k (k = 1, 2) (σ1, σ2) and two substantially parallel straight lines τ l (l = 1, 2) (τ1, τ2). The straight line σ k is preferably substantially parallel to α i . The substantially parallel straight lines τ l are substantially parallel to the straight lines β j (as shown in FIG. 5D).It may be substantially parallel to, or (as shown in FIG. 5C) a substantially parallel straight line β j It may be substantially non-parallel to. Three first dipole magnets (x31) are arranged on one of the straight lines α i Another three first dipole magnets (x31) are arranged on another one of the straight lines α i Still another three first dipole magnets (x31) are arranged on yet another one of the straight lines α i Two third dipole magnets (x33) are arranged on one of the straight lines σ k Two of the third dipole magnets (x33) are arranged on another one of the straight lines σ k The first dipole magnets (x31) are oriented such that their N - poles face the same direction and their magnetic axes are substantially parallel to the surface of the substrate (x20). The third dipole magnets (x33) are oriented such that their N - poles face the same direction and their magnetic axes are substantially parallel to the surface of the substrate (x20), and the third dipole magnets (x33) and the first dipole magnets (x31) have their N - poles facing different directions. The distance between two adjacent substantially parallel straight lines α i is preferably the same (i.e., d1 is equal to d2), and the distance between two substantially parallel straight lines σ k (σ1, σ2) is preferably the same as the distance (d1, d2) between two adjacent substantially parallel straight lines α i The distance between two adjacent substantially parallel straight lines β j is preferably the same (i.e., e1 is equal to e2), and the distance between two adjacent parallel straight lines τ l is preferably the same as the distance (e1, e2) between two adjacent straight lines β j as described above.

[0058] As described herein, the first support matrix (x32) described herein is used to integrally hold the spaced - apart first dipole magnets (x31) of the first magnetic field generating device (x30) described herein and optionally one or more third dipole magnets (x33).

[0059]

[0058] The magnetic assembly (x00) comprises a second magnetic field generating device (x40) as described herein, having one or more second dipole magnets (x41) that are oriented such that the magnetic axis is substantially parallel to the first plane (P) and that are partially or fully embedded in the second support matrix (x42) as described herein.

[0060]

[0059] According to one embodiment, the second magnetic field generating device (x40) includes one second dipole magnet (x41). According to another embodiment, the second magnetic field generating device (x40) includes two or more second dipole magnets (x41) each oriented such that its magnetic axis is substantially parallel to the first plane (P). In the case of an embodiment where the second magnetic field generating device (x40) includes two or more second dipole magnets (x41) as described herein, it is preferable that one of the two second dipole magnets is disposed above the other, and it is preferable that the centers of the two or more second dipole magnets (x41) coincide with each other. That is, the two or more second dipole magnets (x41) in this specification are preferably stacked and coaxially arranged. In the case of an embodiment where the second magnetic field generating device (x40) includes two or more second dipole magnets (x41) as described herein, the two or more second dipole magnets may have their N poles facing the same direction or their N poles facing different directions (see, for example, FIG. 8). In the case of an embodiment where the second magnetic field generating device (x40) includes two or more second dipole magnets (x41) with their N poles facing the same direction, the two or more second dipole magnets (x41) may be arranged overlapping, side by side, or separated, but are preferably in direct contact. In the case of an embodiment where the second magnetic field generating device (x40) includes two or more second dipole magnets (x41) with their N poles facing different directions, the two or more second dipole magnets (x41) are preferably arranged overlapping and are preferably in direct contact. For example, according to one embodiment shown in FIG. 8, the second magnetic field generating device (x40) includes two second dipole magnets (x41) as described herein. The two second dipole magnets (x41) are each oriented such that its magnetic axis is substantially parallel to the first plane (P), their N poles face different directions, one of the two second dipole magnets is disposed above the other, and the centers of the two or more second dipole magnets (x41) coincide with each other and are preferably in direct contact.In the case of an embodiment in which the second magnetic field generating device (x40) includes two or more second dipole magnets (x41) described in this specification, the two second dipole magnets may have the same shape, the same dimensions, and be made of the same material, or they may be different.

[0061]

[0060] The shapes of the first support matrix (x32) of the first magnetic field generating device (x30) and the second support matrix (x42) of the second magnetic field generating device (x40) described in this specification may independently be a disk or a regular polygon (with or without rounding), or an irregular polygon (with or without rounding). The first support matrix (x32) of the first magnetic field generating device (x30) and the second support matrix (x42) of the second magnetic field generating device (x40) described in this specification are independently composed of one or more non-magnetic materials. The non-magnetic material is preferably selected from the group consisting of non-magnetic metals, industrial plastics, and polymers. Examples of 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). Examples of industrial plastics and polymers include, but are not limited to, polyaryletherketone (PAEK) and its derivative 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 polymer. Preferred materials are PEEK (polyetheretherketone), POM (polyoxymethylene), PTFE (polytetrafluoroethylene), Nylon (registered trademark) (polyamide), and PPS.

[0062]

[0061] The magnetic axis of the first magnetic field generating device (x30) and the magnetic axis of the second magnetic field generating device (x40) are substantially parallel to the surface of the substrate (x20) on which the optical effect layer (OEL) is generated and are twisted with respect to each other.

[0063]

[0062] The first magnetic field generating device (x30) described in this specification has a vector sum H1 of the magnetic axes of one or more first dipole magnets (x31), and the second magnetic field generating device (x40) described in this specification has a vector sum H2 of the magnetic axes of one or more second dipole magnets (x41).

[0064]

[0063] Each straight line α i and the vector sum H2 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. In other words, referring to

[0017] , each straight line α i and the vector sum H2 of the magnetic axes of one or more second dipole magnets (x41) form an angle γ in the range of approximately 10° to approximately 80°, the range of approximately 100° to approximately 170°, the range of approximately 190° to approximately 260°, or the range of approximately 280° to approximately 350°.

[0065]

[0064] Since the magnetic axes of the first dipole magnets (x31) of the first magnetic field generating device (x30) are respectively oriented along substantially parallel straight lines α i on each straight line α i the vector sum of all the first magnets (x31) arranged on the straight line α i is parallel to the straight line α i and the vector sum H1 of all the first magnets (x31) of the first magnetic field generating device (x30) is parallel to the straight line α i

[0066] ​

[0065] In an embodiment where the second magnetic field generating device (x40) includes one second dipole magnet (x41), the vector sum H1 of the magnetic axes of the first dipole magnets (x31) constituting the first magnetic field generating device (x30) and the vector sum H2 of the second dipole magnet (x41) of the second magnetic field generating device (x40) are substantially parallel to the surface of the substrate (x20) and are twisted with respect to each other. In the case of these embodiments, each straight line α i In addition to the vector sum H2 of the magnetic axes of the second dipole magnet (x41), the vector sum H1 and the vector sum H2 are substantially non-parallel and substantially non-perpendicular to each other.

[0067]

[0066] In an embodiment where the second magnetic field generating device (x40) includes two or more second dipole magnets (x41), the vector sum H1 of the magnetic axes of the first dipole magnets (x31) constituting the first magnetic field generating device (x30) and the vector sum H2 of one or more second dipole magnets (x41) constituting the second magnetic field generating device (x40) are substantially parallel to the surface of the substrate (x20) and are twisted with respect to each other. In the case of these embodiments, each straight line α i In addition to the vector sum H2 of the magnetic axes of the two or more second dipole magnets (x41), the vector sum H1 and the vector sum H2 are substantially non-parallel and substantially non-perpendicular to each other.

[0068]

[0067] Each straight line α i and the vector sum H2 of the second magnetic field generating device (x40) are substantially parallel to the surface of the substrate (x20) and are twisted with respect to each other (as shown in FIGS. 7 and 8, the angle between them is indicated by γ), and are substantially non-parallel and substantially non-perpendicular to each other. Each straight line α iIn addition to the vector sum H2 of the magnetic axes of the first dipole magnet (x31) of the first magnetic field generating device (x30) and the second dipole magnet (x41) of the second magnetic field generating device (x40), the vector sum H1 and the vector sum H2 are substantially non-parallel and substantially non-perpendicular to each other, preferably forming a range of approximately 20° to approximately 70°, a range of approximately 110° to approximately 160°, a range of approximately 200° to approximately 250°, and a range of approximately 290° to approximately 340°, and more preferably forming an angle γ in a range of approximately 30° to approximately 70°, a range of approximately 120° to approximately 150°, a range of approximately 210° to approximately 240°, or a range of approximately 300° to approximately 330°.

[0069]

[0068] The first dipole magnet (x31) of the first magnetic field generating device (x30) and one or more second dipole magnets (x41) of the second magnetic field generating device (x40) are preferably independently composed of a high coercive force material (also referred to as a ferromagnetic material). Suitable high coercive force materials have a maximum value of energy product (BH) max of at least 20 kJ / m 3 , preferably at least 50 kJ / m 3 , more preferably at least 100 kJ / m 3 , still more preferably at least 200 kJ / m 3 of the material. These include, for example, 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), hexaferrite of the formula MFe 12 O 19 (e.g., strontium hexaferrite (SrO * 6Fe2O3) or barium hexaferrite (BaO * 6Fe2O3), hard ferrite of the formula MFe2O4 (e.g., cobalt ferrite (CoFe2O4) or magnetite (Fe3O4)) (where M is a divalent metal ion), one or more sintered or polymer-bonded magnetic materials selected from the group consisting of ceramic 8 (SI-1-5), RECo5 (RE = Sm or Pr), RE2TM 17 (RE = Sm, TM = Fe, Cu, Co, Zr, Hf), RE2TM 14It is preferably composed of a material selected from the group consisting of rare earth magnetic materials B (RE = Nd, Pr, Dy, TM = Fe, Co), 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 composed of a group of rare earth magnetic materials, more preferably Nd2Fe 14 It is preferably selected from the group consisting of B and SmCo5. Particularly preferred is strontium hexaferrite (SrFe 12 O 19 ) or a processable permanent magnet composite material containing a permanent magnet filler such as neodymium / iron / boron (Nd2Fe 14 B) powder in a plastic or rubber matrix.

[0070]

[0069] The distance (h1) between the uppermost surface of the first magnetic field generating device (x30) and the lowermost surface of the substrate (x20) facing the first magnetic field generating device (x30) is preferably approximately 0.5 mm to approximately 10 mm, more preferably approximately 0.5 mm to approximately 7 mm, and even more preferably approximately 1 mm to 7 mm. The distance (h2) between the lowermost surface of the first magnetic field generating device (x30) described in this specification and the uppermost surface of the second magnetic field generating device (x40) described in this specification is preferably approximately 0 to approximately 10 mm, more preferably approximately 0 to approximately 5 mm, and even more preferably 0.

[0071]

[0070] The magnetic assembly (x00) described herein may further comprise a magnetized plate having one or more surface undulations, engravings, and / or notches representing one or more indicia, the magnetized plate being disposed on top of a first magnetic field generating device (x30). In other words, in the process for generating the 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 top of the magnetized plate disposed on top of the first magnetic field generating device (x30), and the first magnetic field generating device (x30) is disposed on top of a second magnetic field generating device (x40). The first magnetic field generating device (x30), the second magnetic field generating device (x40), and the magnetized plate preferably have substantially coincident centers. As used herein, the term "indicia" is meant to mean designs and patterns and includes, but is not limited to, symbols, alphanumeric characters, motifs, letters, words, numbers, logos, and drawings. One or more surface undulations, engravings, and / or notches of the magnetized plate having indicia are transferred to the non-cured OEL by locally modifying the magnetic field generated by the magnetic assembly (x00) described herein. Suitable examples of the magnetized plate (x60) including one or more surface undulations, engravings, and / or notches described herein can be found in International Publication No. WO 2005 / 002866 A1, International Publication No. WO 2008 / 046702 A1, International Publication No. WO 2008 / 139373 A1, International Publication No. WO 2018 / 019594 A1, and International Publication No. WO 2018 / 033512 A1.

[0072]

[0071] The magnetized plate including one or more engravings and / or notches described herein may be composed of any mechanically processable soft magnetic or hard magnetic material. Examples of hard magnetic materials include, but are not limited to, those described above with respect to the first dipole magnet (x31) of the first magnetic field generating device (x30) and the second dipole magnet (x41) of the second magnetic field generating device (x40). Soft magnetic materials are characterized by low coercivity and high magnetic permeability μ. Each coercivity is 1000 A / m in a measurement according to IEC 60404-1:2000 to enable rapid magnetization and demagnetization-1 is less than. A suitable soft magnetic material has a maximum relative permeability μ Rmax of at least 5. Here, the relative permeability μ R is the permeability μ of the material with respect to the permeability μ0 of free space (μ R = μ / μ0) (Magnetic Materials, Fundamentals and Applications, 2 nd(Ed., Nicola A. Spaldin, p. 16 - 17, Cambridge University Press, 2011). For soft magnetic materials, see, 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 International, 2000; (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 - 9~20 - 16, Butterworth - Heinemann Ltd, 1992.

[0073]

[0072] The magnetized plate described in this specification is preferably a polymer bonded plate of a soft magnetic or hard magnetic material, i.e., a magnetized plate composed of a composite material containing a polymer. The polymer (e.g., a polymer such as rubber or plastic) acts as a structural binder, and the soft magnetic or hard magnetic material acts as a bulking agent or filler. A magnetized plate composed of a composite material containing a polymer and a soft magnetic or hard magnetic material advantageously combines the desired magnetic properties (e.g., the high coercivity of a high magnetic material and the high magnetic 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.

[0074]

[0073] Magnetized plates composed of composite materials containing polymers and permanent magnetic powders are available from many different sources such as Group ARNOLD (Plastiform (registered trademark)) or Materiali Magnetici, Albairate, Milano, Italy (Plastoferrite).

[0075]

[0074] The magnetized plates described in this specification, particularly those composed of composite materials containing the polymers and soft magnetic or hard magnetic materials described herein, can be obtained in any desired size and form (e.g., as thin flexible plates that can be bent and machined (e.g., cut to a predetermined size or shape) using generally available mechanical cutting tools and machines, as well as air or liquid jet cutting, or laser cutting tools).

[0076]

[0075] One or more surface engravings and / or notches of the magnetic plates described herein, in particular, the magnetic plates composed of the polymers and composite materials containing soft magnetic materials or hard magnetic materials described herein, may be generated by any cutting or engraving method known in the art, including casting, molding, manual engraving or mechanical cutting tools (including computer-controlled engraving tools), cutting tools selected from the group consisting of gas or liquid jet cutting tools, chemical etching, electrochemical etching, and laser cutting tools (e.g., CO 2- , Nd-YAG, or excimer laser), but not limited thereto. Also, as understood by those skilled in the art and as described herein, the magnetic plates (x60) described herein, in particular, the magnetic plates composed of the polymers and composite materials containing soft magnetic materials or hard magnetic materials described herein, can also be cut or molded into specific sizes and shapes, rather than engraved. Holes may be cut out, or cut-out pieces may be assembled to the support part.

[0077]

[0076] One or more engravings and notches of the magnetic plates (x60), in particular, the magnetic plates composed of the polymers and composite materials containing soft magnetic materials or hard magnetic materials described herein, may be filled with polymers or contain fillers. In the case of embodiments where the magnetic plates are composed of hard magnetic materials, the fillers may be soft magnetic materials that modify the magnetic flux at the location of one or more engravings / notches, or any other type of magnetic or non-magnetic materials that modify the magnetic field characteristics or simply generate a smooth surface. Also, the magnetic plates, in particular, the magnetic plates (x60) composed of the polymers and composite materials containing soft magnetic materials or hard magnetic materials described herein, may suppress friction, wear, and / or electrostatic charging in high-speed printing applications by facilitating contact with the substrate through surface treatment.

[0078]

[0077] The first dipole magnet (x31) of the first magnetic field generating device (x30), the third dipole magnet (x33) (if present) of the first magnetic field generating device (x30), one or more second dipole magnets (x41) of the second magnetic field generating device (x40), the material of the magnetization plate (if present), and the distances (h1) and (h2) are selected such that the magnetic field as a result of the interaction of the first magnetic field generating device (x30), the second magnetic field generating device (x40), and the magnetization plate (if present) is suitable for the generation of the optical effect layer (OEL) described herein. That is, the resulting magnetic field is disposed in the magnetic field of the magnetic assembly (x00), and when the substrate (x20) having the OEL is inclined about two vertical axes, i.e., the horizontal / transverse axis and the vertical / longitudinal axis, a plurality of dark spots and a plurality of bright spots move, appear, and / or disappear in the diagonal direction to generate an optical impression, and the non-spherical magnetic or magnetizable pigment particles of the uncured radiation-curable coating composition on the substrate (x20) can be oriented.

[0079]

[0078] The present invention further provides a printing apparatus including a rotary magnetic cylinder and one or more magnetic assemblies (x00) described herein, wherein the one or more magnetic assemblies (x00) are attached to a circumferential or axial groove of the rotary magnetic cylinder, and a printing apparatus including a flatbed printing unit and one or more magnetic assemblies (x00) described herein, wherein the one or more magnetic assemblies are attached to a recess of the flatbed printing unit. The present invention further provides the use of the printing apparatus for generating the optical effect layer (OEL) described herein on a substrate as described herein.

[0080]

[0079] The rotary magnetic cylinder is intended for use in a printing or coating device, in combination with a printing or coating device, or as part of a printing or coating device, and supports one or more magnetic assemblies described herein. In one embodiment, the rotary magnetic cylinder is part of a rotary, sheet-fed, or web-fed industrial printing press that operates continuously at a high printing speed.

[0081]

[0080] The flatbed printing unit is intended for use in a printing or coating device, for combined use with a printing or coating device, or for incorporation as part of a printing or coating device, and supports one or more of the magnetic assemblies described herein. In one embodiment, the flatbed printing unit is part of a sheet-fed industrial printing press that operates discontinuously.

[0082]

[0081] A printing apparatus comprising the rotating magnetic cylinder described herein or the flatbed printing unit described herein may include a substrate supply device that supplies a substrate as described herein having a layer of the non-spherical magnetic or magnetizable pigment particles described herein, such that the magnetic assembly generates a magnetic field that acts on the pigment particles to orient them to form the OEL described herein. In one embodiment of a printing apparatus comprising the rotating magnetic cylinder described herein, the substrate is supplied by the substrate supply device in the form of a sheet or web. In one embodiment of a printing apparatus comprising the flatbed printing unit described herein, the substrate is supplied in the form of a sheet.

[0083]

[0082] A printing apparatus comprising the rotating magnetic cylinder described herein or the flatbed printing unit described herein is a coating or printing unit that applies a radiation-curable coating composition containing the non-spherical magnetic or magnetizable pigment particles described herein to the substrate described herein, the radiation-curable coating composition containing non-spherical magnetic or magnetizable pigment particles that are oriented by the magnetic field generated by the magnetic assembly described herein to form an optical effect layer (OEL), and may include a coating or printing unit. In one embodiment of a printing apparatus comprising the rotating magnetic cylinder described herein, the coating or printing unit operates according to a continuous rotation process. In one embodiment of a printing apparatus comprising the flatbed printing unit described herein, the coating or printing unit operates according to a linear discontinuous process.

[0084]

[0083] A printing apparatus comprising the rotating magnetic cylinder described herein or the flatbed printing unit described herein may include a curing unit that at least partially cures a radiation-curable coating composition containing non-spherical magnetic or magnetizable pigment particles magnetically oriented by the magnetic assembly described herein, thereby fixing the orientation and position of the non-spherical magnetic or magnetizable pigment particles to produce an optical effect layer (OEL).

[0085]

[0084] The present invention provides a process and method for producing the optical effect layer (OEL) described herein on the substrate (x20) described herein, and an optical effect layer (OEL) obtained thereby, wherein the process comprises: i) applying a radiation-curable coating composition in a first state containing the non-spherical magnetic or magnetizable pigment particles described herein to the surface of the substrate (x20) to form a coating layer (x10). The radiation-curable coating composition is in a first state for forming the coating layer (x10). The radiation-curable coating composition is in a first state, i.e., a liquid or paste state, and is sufficiently wet or flexible such that the non-spherical magnetic or magnetizable pigment particles dispersed therein are capable of free movement, rotation, and / or orientation upon exposure to a magnetic field.

[0086]

[0085] Step i) described herein may be performed by a coating process or a printing process such as, for example, a roller and spray coating process. Step i) described herein is preferably selected from the group consisting of screen printing, gravure printing, flexographic printing, inkjet printing, and intaglio printing (also referred to in the art as copperplate intaglio printing and steel die intaglio printing), and more preferably is performed by a printing process selected from the group consisting of screen printing, gravure printing, and flexographic printing.

[0087]

[0086] After the application (step i) of the radiation-curable coating composition described herein to the surface of the substrate (x20) described herein, at least a portion of the non-spherical magnetic or magnetizable pigment particles are aligned along the magnetic field lines generated by the magnetic assembly (x00) by exposing the radiation-curable coating composition to the static magnetic field of the magnetic assembly (x00) described herein, either partially simultaneously or simultaneously (step ii).

[0088]

[0087] After or partially simultaneously with the step of aligning at least a portion of the non-spherical magnetic or magnetizable pigment particles by applying the magnetic field described herein, the orientation of the non-spherical magnetic or magnetizable pigment particles is fixed or stopped. It should be noted in particular that the radiation-curable coating composition needs to have a first state, namely a liquid or paste state, and is sufficiently wet or flexible so that the non-spherical magnetic or magnetizable pigment particles dispersed in the radiation-curable coating composition can move, rotate, and / or be oriented freely by exposure to the magnetic field. It also needs to have a second cured (e.g., solid) state, in which case the non-spherical magnetic or magnetizable pigment particles are fixed or stopped in their respective positions and orientations.

[0089]

[0088] From the above, the process for generating an optical effect layer (OEL) on a substrate (x20) described herein includes step iii) of 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 magnetizable pigment particles in their respective adopted positions and orientations. Step iii) of at least partially curing the radiation curable coating composition may be carried out after or partially simultaneously with step ii) of orienting / alignment at least a portion of the non-spherical magnetic or magnetizable pigment particles by application of a magnetic field as described herein. Step iii) of at least partially curing the radiation curable coating composition is preferably carried out partially simultaneously with step ii) of orienting / alignment at least a portion of the non-spherical magnetic or magnetizable pigment particles by application of a magnetic field as described herein. By "partially simultaneously", a portion of both steps is carried out simultaneously. That is, the execution timing of each step partially overlaps. In the context described herein, when curing is carried out partially simultaneously with the orientation step ii), it should be understood that curing is effective after orientation so that there is time for the pigment particles to orient before complete or partial curing or solidification of the OEL.

[0090]

[0089] The process for generating the optical effect layer (OEL) described herein includes exposing the coating layer (x10) to a dynamic magnetic field of the apparatus so as to biaxially orient at least a portion of the platelet-shaped magnetic or magnetizable pigment particles before or at least partly simultaneously with step ii) (step ii2)), and the process may further include step (step ii2)) which is performed before or partly simultaneously with step ii) and before step iii). A process including the step of exposing the coating composition to a dynamic magnetic field of the apparatus so as to biaxially orient at least a portion of the platelet-shaped magnetic or magnetizable pigment particles is disclosed in WO 2015 / 086257 A1. After the exposure of the coating layer (x10) to the dynamic magnetic field of the magnetic assembly (x30) as described in WO 2015 / 086257 A1, the platelet-shaped magnetic or magnetizable pigment particles are further reoriented using the apparatus described herein while the coating layer (x10) is still wet or flexible so that the internal platelet-shaped magnetic or magnetizable pigment particles can further move and rotate. Performing biaxial orientation means orienting the platelet-shaped magnetic or magnetizable pigment particles such that two main axes are constrained. That is, each of the platelet-shaped magnetic or magnetizable pigment particles is considered to have a major axis in the plane of the pigment particle and a minor axis orthogonal to the plane of the pigment particle. The major axis and the minor axis of the platelet-shaped magnetic or magnetizable pigment particles are each oriented according to the dynamic magnetic field. Practically, this causes the magnetic or magnetizable pigment particles adjacent to each other closely in space to be essentially parallel to each other. To perform biaxial orientation, the magnetic or magnetizable pigment particles need to be subjected to an external magnetic field that is strongly dependent on time.

[0091]

[0090] A particularly preferred apparatus for biaxially orienting magnetic or magnetizable pigment particles is disclosed in European Patent Application Publication No. 2 157 141 A1. The apparatus disclosed in European Patent Application Publication No. 2 157 141 A1 provides a dynamic magnetic field that changes the direction of rapidly vibrating magnetic or magnetizable pigment particles until the two main axes, the X-axis and the Y-axis, are substantially parallel to the substrate surface. That is, the magnetic or magnetizable pigment particles form a stable sheet-like configuration with the X-axis and the Y-axis substantially parallel to the substrate surface and rotate until they are flattened in the two dimensions. Another particularly preferred apparatus for biaxially orienting magnetic or magnetizable pigment particles includes a linear permanent magnet Halbach array, i.e., an assembly comprising a plurality of magnets with different magnetization directions. A detailed description of Halbach permanent magnets is given by Z.Q. 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 characteristic of being concentrated on one side and weakening to almost zero on the other side. International Publication No. 2016 / 083259 A1 discloses an apparatus suitable for biaxially orienting magnetic or magnetizable pigment particles, the apparatus comprising a Halbach cylinder assembly. Another particularly preferred apparatus for biaxially orienting magnetic or magnetizable pigment particles is a rotating magnet, including a disk-shaped rotating magnet or a magnetic assembly that is essentially magnetized along their diameters. Suitable rotating magnets or magnetic assemblies are described in U.S. Patent Application Publication No. 2007 / 0172261 A1, and by generating a radially symmetric time-varying magnetic field, biaxial orientation of the magnetic or magnetizable pigment particles in an uncured or unfixed coating composition becomes possible. These magnets or magnetic assemblies are driven by a shaft (or spindle) connected to an external motor. Chinese Patent No. 102529326 B discloses an example of an apparatus comprising a rotating magnet that may be suitable for biaxially orienting magnetic or magnetizable pigment particles.In a preferred embodiment, a suitable apparatus for biaxially orienting magnetic or magnetizable pigment particles is a disk-shaped rotating magnet or magnetic assembly without a shaft, constrained within a housing made of a non-magnetic material, preferably a non-conductive material, and driven by one or more magnet wire coils wound around the housing. Examples of such disk-shaped rotating magnets or magnetic assemblies without a shaft are disclosed in International Publication No. WO 2015 / 082344 A1, International Publication No. WO 2016 / 026896 A1, and International Publication No. WO 2018 / 141547 A1.

[0092]

[0091] The first and second states of the radiation-curable coating composition are provided by using certain radiation-curable coating compositions. For example, the components other than the non-spherical magnetic or magnetizable pigment particles of the radiation-curable coating composition may be in the form of a radiation-curable coating composition for use in ink or security applications (e.g., banknote printing). The first and second states described above are provided by using a material whose viscosity increases in response to exposure to electromagnetic radiation. That is, the fluid binder material is converted by curing or solidification into a second state in which the non-spherical magnetic or magnetizable pigment particles are fixed in their respective current positions and orientations and cannot move or rotate within the binder material.

[0093]

[0092] As is known to those skilled in the art, the components contained in the radiation-curable coating composition to be applied onto the surface of a substrate, etc., and the physical properties of the radiation-curable coating composition need to meet the requirements of the process used for the transfer of the radiation-curable coating composition onto the substrate surface. As a result, the binder material contained in the radiation-curable coating composition described herein is usually selected from materials known in the art and is determined by the coating or printing process used for the application of the radiation-curable coating composition and the selected radiation curing process.

[0094]

[0093] In the optical effect layer (OEL) described herein, the non-spherical magnetic or magnetizable pigment particles described herein are dispersed in a cured / solidified radiation-curable coating composition containing a curing binder material that fixes / stops the orientation of the magnetic or magnetizable pigment particles. The curing binder material is at least partially transparent to electromagnetic radiation of various wavelengths included in the range of 200 nm to 2500 nm. Thus, the binder material is at least partially transparent to electromagnetic radiation of various wavelengths included in the wavelength range including the infrared, visible, and UV (ultraviolet) portions of the electromagnetic spectrum, such that in at least its cured or solid state (also referred to herein as the second state), the cured or solid state particles contained in the binder material and their respective orientations can be recognized through the binder material. The curing binder material is preferably at least partially transparent to electromagnetic radiation of various wavelengths included in the range of 200 nm to 800 nm, more preferably 400 nm to 700 nm. As used herein, the term "transparent" indicates that the transmittance of electromagnetic radiation through a 20 μm layer of the curing binder material present in the OEL (excluding platelet-shaped magnetic or magnetizable pigment particles, but including all other optional components of the OEL if any) at the corresponding (one or more) wavelengths is at least 50%, more preferably at least 60%, and even more preferably at least 70%. This can be determined by measuring the transmittance of a test piece of the curing binder material (excluding non-spherical magnetic or magnetizable pigment particles) according to established test methods such as DIN 5036-3 (November 1979). When the OEL functions as a secret security feature, technical means are usually required to detect the (complete) optical effect generated by the OEL under each lighting condition including the selected non-visible wavelength. For such detection, it is necessary to select the wavelength of the incident radiation in the region outside the visible range (e.g., the near UV region). The infrared, visible, and ultraviolet portions of the electromagnetic spectrum approximately correspond to the wavelength ranges of 700 to 2500 nm, 400 to 700 nm, and 200 to 400 nm, respectively.

[0095] As described above, the radiation curable coating composition described in this specification is determined by the coating or printing process used for the application of the radiation curable coating composition and the selected curing process. For the curing of the radiation curable coating composition, it is preferable that a simple temperature rise (for example, up to 80 ° C) that may occur during normal use of the article provided with the OEL described in this specification involves an irreversible chemical reaction. The terms "curing" or "curable" represent a process in which at least one component in the applied radiation curable coating composition changes to a polymer material having a larger molecular weight than the starting material by chemical reaction, crosslinking, or polymerization. In radiation curing, the viscosity of the radiation curable coating composition instantaneously increases upon exposure to the curing radiation, further movement of the pigment particles is suppressed, and as a result, information loss after the magnetic orientation step is suppressed, which is convenient. The curing step (step (iii)) is preferably carried out by radiation curing including UV / visible light radiation curing or electron beam radiation curing, more preferably by UV / visible light radiation curing.

[0096]

[0095] Therefore, examples of the radiation curable coating composition suitable for the present invention include radiation curable compositions that can be cured by UV / visible light radiation (hereinafter referred to as UV / visible light 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, published by John Wiley & Sons in collaboration with SITA Technology Limited in 1996. 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. Therefore, the radiation curable coating composition containing the non-spherical magnetic or magnetizable pigment particles described herein is preferably at least partially cured by UV / visible light radiation, preferably UV-A (315 - 400 nm) or blue (400 - 500 nm) spectral region narrowband LED light, and most preferably a high-power LED light source with a normal emission bandwidth in the spectral region of 350 nm - 450 nm and a range of 20 nm - 50 nm. It is also possible to increase the curing rate of the radiation curable coating composition by using UV radiation from a mercury lamp or a doped mercury lamp.

[0097]

[0096] The UV·visible radiation curable coating composition preferably contains one or more compounds selected from the group consisting of radical curable compounds and cationic curable compounds. The UV·visible radiation curable coating composition described in this specification may be a hybrid system and contains a mixture of one or more cationic curable compounds and one or more radical curable compounds. The cationic curable compound cures by a cationic mechanism that typically involves the activation by radiation of one or more photoinitiators to release a cationic species such as an acid, thereby curing the radiation curable coating composition by the reaction and / or crosslinking of monomers and / or oligomers. The radical curable compound cures by a free radical mechanism that typically involves the activation by radiation of one or more photoinitiators to generate radicals, thereby initiating polymerization and curing the radiation curable coating composition. Depending on the monomers, oligomers, or prepolymers used to prepare the binder contained in the UV·visible radiation curable coating composition described in this specification, different photoinitiators can be used. Suitable examples of free radical photoinitiators are known to those skilled in the art and include acetophenone, benzophenone, benzyldimethylketal, α - aminoketone, α - hydroxyketone, phosphine oxide, and phosphine oxide derivatives, as well as mixtures of two or more of these, but are not limited thereto. Suitable examples of cationic photoinitiators are known to those skilled in the art and include 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 of these, but are not limited thereto.Other examples of useful photoinitiators can be found in standard textbooks such as "Photoinitiators for Free Radical Cationic and Anionic Polymerization", 2nd Edition, Volume 3 of "Chemistry & Technology of UV & EB Formulation for Coatings, Inks & Paints" by J. V. Crivello and K. Dietliker, published in 1998 by John Wiley & Sons in association with SITA Technology Limited, edited by G. Bradley. Also, in order to achieve efficient curing, it is considered advantageous to include a sensitizer in combination with one or more photoinitiators. General 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 of these. One or more photoinitiators contained in the UV-visible radiation curable coating composition are preferably present in a total amount of approximately 0.1 wt% to approximately 20 wt%, more preferably approximately 1 wt% to approximately 15 wt%, where the weight percentages are based on the total weight of the UV-visible radiation curable coating composition.

[0098]

[0097] The radiation curable coating composition described herein may further comprise one or more machine-readable materials selected from the group consisting of one or more marker substances or tracking additives and / or magnetic materials (different from the platelet-shaped magnetic or magnetizable 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 for authenticating the layer or an article containing the layer by use of a specific authentication device.

[0099]

[0098] The radiation-curable coating composition described in this specification may further contain one or more coloring components selected from the group consisting of organic pigment particles, inorganic pigment particles, and organic dyes, and / or non-magnetic or non-magnetizable optically variable pigments, and / or one or more additives. The latter include compounds and materials used for adjusting the physical, rheological, and chemical parameters of radiation-curable coating compositions such as viscosity (e.g., solvents, thickeners, and surfactants), consistency (e.g., inhibitors, fillers, and plasticizers), foaming properties (e.g., defoamers), lubricity (waxes, oils), UV stability (light stabilizers), adhesion, antistatic properties, storage stability (polymerization inhibitors), gloss, etc., but are not limited thereto. The additives described in this specification may be present in the radiation-curable coating composition in known amounts and forms in the art, such as so-called nanomaterials in which at least one of the dimensions of the additive is in the range of 1 to 1000 nm.

[0100]

[0099] The radiation-curable coating composition described in this specification contains the non-spherical magnetic or magnetizable pigment particles described in this specification. The non-spherical magnetic or magnetizable pigment particles are preferably present in an amount of approximately 2 wt% to approximately 40 wt%, more preferably approximately 4 wt% to approximately 30 wt%. 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 any other optional components of the radiation-curable coating composition.

[0101]

[0100] The non-spherical magnetic or magnetizable pigment particles described herein are defined to have non-isotropic reflectivity with respect to incident electromagnetic radiation, at least a portion of the cured or solidified binder material being transparent, due to their non-spherical shape. As used herein, the term "non-isotropic reflectivity" means that the proportion of incident radiation from a first angle that is reflected by the particles in a particular (observed) direction (second angle) is a function of the orientation of the particles, i.e., the magnitude of the reflection in the observed direction can vary depending on the change in the orientation of the particles with respect to the first angle. More preferably, the non-spherical magnetic or magnetizable pigment particles described herein have non-isotropic reflectivity with respect to incident electromagnetic radiation in part or all of a wavelength range of approximately 200 to approximately 2500 nm, more preferably approximately 400 to approximately 700 nm, such that the reflection by the particles changes in a particular direction with a change in the orientation of the particles. As is known to those skilled in the art, while conventional pigment particles exhibit the same color and reflectivity regardless of particle orientation, the magnetic or magnetizable pigment particles described herein differ from conventional pigments in that they exhibit reflectivity, color, or both, determined by particle orientation. The non-spherical magnetic or magnetizable pigment particles described herein are preferably platelet-shaped magnetic or magnetizable pigment particles.

[0102]

[0101] Suitable examples of the non-spherical magnetic or magnetizable pigment particles described in this specification include magnetic metals 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 pigment particles containing mixtures of two or more of these, but are not limited thereto. The term "magnetic" with respect to metals, alloys, and oxides refers to ferromagnetic or ferrimagnetic metals, alloys, and oxides. The magnetic oxides of chromium, manganese, cobalt, iron, nickel, or mixtures of two or more thereof may be pure or mixed oxides. Examples of magnetic oxides include iron oxides such as hematite (Fe2O3), magnetite (Fe3O4), chromium dioxide (CrO2), magnetic ferrite (MFe2O4), magnetic spinel (MR2O4), magnetic hexaferrite (MFe 12 O 19 ), magnetic orthoferrite (RFeO3), magnetic garnet (M3R2(AO4)3), etc., but are not limited thereto. Here, M represents a divalent metal, R represents a trivalent metal, and A represents a tetravalent metal.

[0103]

[0102] Examples of the non-spherical magnetic or magnetizable pigment particles described in this specification include pigment particles containing 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, but are not limited thereto. The platelet-shaped magnetic or magnetizable pigment particles may have a multilayer structure including one or more other layers. The one or more other layers are preferably 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), preferably magnesium fluoride (MgF2), silicon oxide (SiO), silicon dioxide (SiO2), titanium oxide (TiO2), zinc sulfide (ZnS), and aluminum oxide (Al2O3), more preferably silicon dioxide (SiO2), layer A independently composed of one or more materials, metals and metal alloys, preferably one or more materials selected from the group consisting of reflective metals and reflective metal alloys, 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 preferably one or more materials selected from the group consisting of aluminum (Al), chromium (Cr), nickel (Ni), and alloys thereof, even more preferably layer B independently composed of aluminum (Al), or a combination of one or more layers A as described above and one or more layers B as described above.General examples of the platelet-shaped magnetic or magnetizable pigment particles having the above-described multilayer structure include, but are not limited to, A / M multilayer structure, A / M / A multilayer structure, A / M / B multilayer structure, A / B / M / A multilayer structure, A / B / M / B multilayer structure, A / B / M / B / A multilayer structure, B / M multilayer structure, B / M / B multilayer structure, B / A / M / A multilayer structure, B / A / M / B multilayer structure, B / A / M / B / A multilayer structure. Here, layer A, magnetic layer M, and layer B are selected from the above-described layers.

[0104] According to one embodiment, at least a part of the non-spherical magnetic or magnetizable pigment particles described herein has a dielectric / reflector / magnetic / reflector / dielectric multilayer structure. The reflector layer described herein is independently composed of the group consisting of metals and metal alloys as described above with respect to layer B, the dielectric layer is independently composed of the group consisting of materials as described above with respect to layer A, and the magnetic layer preferably contains one or more of the magnetic metals or magnetic alloys as described above with respect to layer M. Alternatively, the dielectric / reflector / magnetic / reflector / dielectric multilayer structure described herein may be multilayer pigment particles considered to be safe for human health and the environment. The magnetic layer contains a magnetic alloy having a composition substantially free of nickel and containing approximately 40 wt% to approximately 90 wt% of iron, approximately 10 wt% to approximately 50 wt% of chromium, and approximately 0 wt% to approximately 30 wt% of aluminum.

[0105]

[0104] At least a part of the non-spherical magnetic or magnetizable pigment particles described in this specification may be composed of non-spherical discoloring magnetic or magnetizable pigment particles and / or non-spherical magnetic or magnetizable pigment particles having no discoloring properties. At least a part of the non-spherical magnetic or magnetizable pigment particles described in this specification is preferably composed of non-spherical discoloring magnetic or magnetizable pigment particles. The overt security feature brought about by the discoloring properties of the non-spherical discoloring magnetic or magnetizable pigment particles enables an article or security document having an ink, a radiation-curable coating composition, a coating, or a layer containing the non-spherical discoloring magnetic or magnetizable pigment particles described in this specification to be easily detected, recognized, and / or distinguishable from its possible counterfeits by human senses alone. In addition to this, the optical properties of the non-spherical discoloring magnetic or magnetizable pigment particles may be used as a machine-readable tool for optical effect layer (OEL) recognition. Therefore, in an authentication process for analyzing the optical (e.g., spectral) properties of the pigment particles, the optical properties of the non-spherical discoloring magnetic or magnetizable pigment particles may be used simultaneously as a secret or semi-secret security feature. When non-spherical discoloring magnetic or magnetizable pigment particles are used in a radiation-curable coating composition for generating an OEL, the significance as a security feature in the security document application of the OEL is enhanced. Such materials (i.e., non-spherical discoloring magnetic or magnetizable pigment particles) are for the security document printing industry and are generally not commercially available.

[0106]

[0105] Furthermore, since the non-spherical magnetic or magnetizable pigment particles described in this specification are machine-readable due to their magnetism, a radiation-curable coating composition containing these pigment particles may be configured to be detected by, for example, a specific magnetic detector. Therefore, a radiation-curable coating composition containing the non-spherical magnetic or magnetizable pigment particles described in this specification can be used as a secret or semi-secret security element (authentication tool) for security documents.

[0107] As described above, the non-spherical magnetic or magnetizable pigment particles preferably comprise at least in part non-spherical discoloring magnetic or magnetizable pigment particles. These are more preferably selectable 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 containing a magnetic material, and mixtures of two or more thereof.

[0108]

[0107] Magnetic thin film interference pigment particles are known to those skilled in the art and are disclosed, for example, in U.S. Patent No. 4,838,648, International Publication No. 2002 / 073250 A2, European Patent No. 0 686 675 B1, International Publication No. 2003 / 000801 A2, U.S. Patent No. 6,838,166, International Publication No. 2007 / 131833 A1, European Patent Application Publication No. 2 402 401 A1, and the references cited therein. The magnetic thin film interference pigment particles preferably include pigment particles having a 5-layer Fabry-Perot multilayer structure, and / or pigment particles having a 6-layer Fabry-Perot multilayer structure, and / or pigment particles having a 7-layer Fabry-Perot multilayer structure.

[0109]

[0108] A preferred 5-layer Fabry-Perot multilayer structure consists of a multilayer structure of absorber / dielectric / reflector / dielectric / absorber, wherein the reflector and / or absorber is also a magnetic layer, and preferably the reflector and / or absorber is a magnetic layer containing nickel, iron, and / or cobalt, a magnetic alloy containing nickel, iron, and / or cobalt, and / or a magnetic oxide containing nickel (Ni), iron (Fe), and / or cobalt (Co).

[0110]

[0109] A preferred 6-layer Fabry-Perot multilayer structure consists of a multilayer structure of absorber / dielectric / reflector / magnetic / dielectric / absorber.

[0111]

[0110] A preferred 7-layer Fabry-Perot multilayer structure consists of a multilayer structure of absorber / dielectric / reflector / magnetic / reflection pair / dielectric / absorber as disclosed in U.S. Patent No. 4,838,648.

[0112]

[0111] The reflector layer described in this specification is selected from the group consisting of metals and metal alloys, preferably selected from the group consisting of reflective metals and reflective metal alloys, more preferably selected from the group consisting of aluminum (Al), silver (Ag), copper (Cu), gold (Au), platinum (Pt), tin (Sn), titanium (Ti), palladium (Pd), rhodium (Rh), niobium (Nb), chromium (Cr), nickel (Ni), and alloys thereof, still more preferably one or more materials selected from the group consisting of aluminum (Al), chromium (Cr), nickel (Ni), and alloys thereof, and most preferably independently composed of aluminum (Al). The dielectric layer is preferably 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), etc., and metal oxides such as silicon monoxide (SiO), silicon dioxide (SiO2), titanium dioxide (TiO2), aluminum oxide (Al2O3), etc., more preferably one or more materials selected from the group consisting of magnesium fluoride (MgF2) and silicon dioxide (SiO2), and most preferably independently composed of magnesium fluoride (MgF2). The absorber layer is 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), their metal oxides, metal sulfides, metal carbides, and metal alloys, more preferably selected from the group consisting of chromium (Cr), nickel (Ni), iron (Fe), their metal oxides, and metal alloys, still more preferably one or more materials selected from the group consisting of chromium (Cr), nickel (Ni), and their metal alloys, and is most preferably independently composed thereof.The magnetic layer preferably contains nickel (Ni), iron (Fe), and / or cobalt (Co), a magnetic alloy containing nickel (Ni), iron (Fe), and / or cobalt (Co), and / or a magnetic oxide containing nickel (Ni), iron (Fe), and / or cobalt (Co). When magnetic thin film interference pigment particles including a 7-layer Fabry-Perot structure are preferred, it is particularly preferred that the magnetic thin film interference pigment particles have a multi-layer structure of a 7-layer Fabry-Perot absorber / dielectric / reflector / magnetic body / reflector / dielectric / absorber composed of a Cr / MgF2 / Al / M / Al / MgF2 / Cr multi-layer structure, and M is a magnetic layer containing nickel (Ni), iron (Fe), and / or cobalt (Co), a magnetic alloy containing nickel (Ni), iron (Fe), and / or cobalt (Co), and / or a magnetic oxide containing nickel (Ni), iron (Fe), and / or cobalt (Co).

[0113]

[0112] The magnetic thin film interference pigment particles described in this specification are considered safe for human health and the environment, and may be, for example, multi-layer pigment particles based on a 5-layer Fabry-Perot multi-layer structure, a 6-layer Fabry-Perot multi-layer structure, and a 7-layer Fabry-Perot multi-layer structure. The pigment particles include one or more magnetic layers containing a magnetic alloy having a composition substantially free of nickel and containing approximately 40 wt% to approximately 90 wt% iron, approximately 10 wt% to approximately 50 wt% chromium, and approximately 0 wt% to approximately 30 wt% aluminum. General examples of multi-layer pigment particles considered safe for human health and the environment can be found in European Patent Application Publication No. 2 402 401 A1, the entire contents of which are incorporated herein by reference.

[0114]

[0113] The magnetic thin film interference pigment particles described in this specification are typically manufactured by conventional deposition techniques of different required layers onto a web. For example, after depositing a desired number of layers by physical vapor deposition (PVD), chemical vapor deposition (CVD), or electroplating, the layer stack is removed from the web by dissolving the release layer in a suitable solvent or peeling the material from the web. Then, platelet-shaped pigment particles are obtained by grinding such obtained material, which need to be further processed by grinding, milling (e.g., jet milling process, etc.), or any suitable method to obtain pigment particles of the required size. The resulting product consists of flat platelet-shaped pigment particles with broken edges, irregular shapes, and different aspect ratios. Details regarding the preparation of suitable platelet-shaped magnetic thin film interference pigment particles can be found, for example, in European Patent Application Publication No. 1 710 756 A1 and European Patent Application Publication No. 1 666 546 A1, which are hereby incorporated by reference into this specification.

[0115]

[0114] 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 International Publication No. 2006 / 063926 A1, U.S. Patent No. 6,582,781, and U.S. Patent No. 6,531,221. International Publication No. 2006 / 063926 A1 discloses single layers and pigment particles obtained from such single layers having specific properties such as high brightness and color-changing properties, as well as magnetizability. The single layers of this disclosure and the pigment particles obtained by grinding such single layers contain a three-dimensionally crosslinked cholesteric liquid crystal mixture and magnetic nanoparticles. U.S. Patent No. 6,582,781 and U.S. Patent No. 6,410,130 disclose cholesteric multi-layer pigment particles with an arrangement of A 1 / B / A 2 where A 1 and A 2 may be the same or different and each contains at least one cholesteric layer. B is the layer A 1 and A 2It is an intermediate layer that absorbs all or part of the light sent from and imparts magnetic properties. U.S. Patent No. 6,531,221 discloses platelet-shaped cholesteric multilayer pigment particles having an array of A / B and optionally containing C. Here, A and C are absorption layers containing pigment particles that impart magnetic properties, and B is a cholesteric layer.

[0116]

[0115] Suitable interference-coated pigments containing one or more magnetic materials include, but are not limited to, structures composed of substrates selected from the group consisting of cores coated with one or more layers. Here, at least one of the core or one or more layers has magnetism. For example, a suitable interference-coated pigment is a core composed of a magnetic material as described above, coated with one or more layers composed of one or more metal oxides, and includes a core, or is composed of a core composed of synthetic or natural mica, layered silicates (such as talc, kaolin, and sericite), glass (such as borosilicate), silicon dioxide (SiO2), aluminum oxide (Al2O3), titanium oxide (TiO2), graphite, and mixtures of two or more of these. Further, one or more other layers such as a coloring layer may be present.

[0117]

[0116] The non-spherical magnetic or magnetizable pigment particles described herein may be surface-treated for protection against any degradation that may occur in the radiation-curable coating composition and / or to facilitate incorporation into the radiation-curable coating composition, and usually, corrosion inhibitors and / or wetting agents may be used.

[0118]

[0117] The substrate described in this specification is preferably selected from the group consisting of paper or cellulose, paper-containing materials, glass, metal, ceramic, plastic, and other fibrous materials such as polymers, metallized plastics or polymers, composites, and mixtures or combinations thereof. Representative papers, paper-like, or other fibrous materials are composed of various fibers such as abaca, cotton, hemp, wood pulp, and mixtures thereof, but are not limited thereto. As is well known to those skilled in the art, cotton and cotton / hemp mixtures are preferred for banknotes, and wood pulp is generally 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), and poly(ethylene 2,6-naphthalate) (PEN), and polyvinyl chloride (PVC). As the substrate, for example, spunbond olefin fibers sold under the trademark Tyvek® can also be used. Representative examples of metallized plastics or polymers include the above-mentioned plastic or polymer materials having a metal disposed continuously or discontinuously on the surface. Representative examples of metals include 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, but are not limited thereto. The metallization of the above-mentioned plastic or polymer materials may be performed by an electrodeposition process, a high-vacuum coating process, or a sputtering process. Representative examples of composites include multi-layer structures or laminates of paper and at least one plastic or polymer material as described above, and plastics and / or polymer fibers incorporated into paper-like or fibrous materials as described above, but are not limited thereto. Naturally, the substrate may also contain other additives known to those skilled in the art, such as sizing agents, bleaching agents, processing aids, reinforcing or wetting agents. The substrate described in this specification may be provided in the form of a web (e.g., a continuous sheet of the above-mentioned materials) or in the form of a sheet.When the optical effect layer (OEL) generated in accordance with the present invention is on a security document, for the purpose of further enhancing the security level and resistance against forgery and illegal copying of the security document, the substrate may comprise printing, coating, laser marking, or laser perforation stamps, watermarks, security threads, fibers, blanks, luminescent compounds, windows, foils, decals, and combinations of two or more thereof. For the same purpose of further enhancing the security level and resistance against forgery and illegal copying of the security document, the substrate may contain one or more marker substances or tracking additives and / or machine-readable substances (for example, luminescent substances, UV / visible / IR absorbing substances, magnetic substances, and combinations thereof).

[0119]

[0118] 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 stamps, dots, and / or lines. The shape of the coating layer (x10) may consist of lines, dots, and / or stamps separated from each other by areas with nothing.

[0120]

[0119] The optical effect layer (OEL) described herein may be provided directly on a substrate so as to remain permanently (for example, in the case of banknote applications). Alternatively, the OEL may be provided on a temporary substrate for generation and later removed. This may, for example, facilitate the generation of the OEL, especially when the binder material remains in a fluid state. Thereafter, when the coating composition is at least partially cured to generate the OEL, the temporary substrate may be removed from the OEL.

[0121] Alternatively, an adhesive layer may be present on the OEL or the substrate provided with the OEL. The adhesive layer may be present on the substrate surface on the side opposite to the surface on which the OEL is provided, or may be present on the same surface as the OEL and on top of the OEL. Therefore, the adhesive layer may be applied to the OEL or the substrate. Such an article may be attached to any type of document or other article without processes such as machinery or printing involving a great deal of labor. Alternatively, the substrate described herein provided with the OEL described herein may be in the form of a transfer foil applicable to a document or article in an independent transfer step. For this purpose, a release coating is provided on the substrate, and on top of it, the OEL is generated as described herein. One or more adhesive layers may be applied on the OEL thus generated.

[0122]

[0121] This specification also describes a substrate provided with two or more, i.e., two, three, four, etc., optical effect layers (OELs) obtained by the process described herein.

[0123]

[0122] Furthermore, this specification describes an article provided with an optical effect layer (OEL) generated according to the present invention, in particular, a security document, a decorative element or an object. These articles, in particular, security documents, decorative elements or objects may be provided with two or more (e.g., two, three, etc.) OELs generated according to the present invention.

[0124]

[0123] As described above, the optical effect layer (OEL) generated according to the present invention may be used for decorative purposes and for the protection and authentication of security documents. Representative examples of decorative elements or objects include, but are not limited to, luxury goods, cosmetic packages, automotive parts, electronic / home appliance products, furniture, and nail lacquers.

[0125] As security documents, valuable documents and valuable goods may be mentioned, but are not limited thereto. Representative examples of valuable documents include banknotes, certificates, tickets, checks, vouchers, revenue stamps and tax stamps, contracts, etc., identity documents such as passports, identity certificates, visas, driver's licenses, bank cards, credit cards, transaction cards, access documents or cards, admission tickets, public transportation tickets or certificates, etc. Banknotes, identity documents, entitlement documents, driver's licenses, and credit cards are preferred, but are not limited thereto. The term "value commercial good" particularly represents package materials of articles for which the contents of the package, such as genuine medicines, etc., should be guaranteed by protection against forgery and / or illegal reproduction, such as cosmetics, dietary supplements, pharmaceuticals, alcohol, tobacco products, beverages or foodstuffs, electrical / electronic products, textiles or jewelry. Examples of these package materials include, but are not limited to, labels and seals such as authentication brand labels and anti-counterfeiting labels. Note that the disclosed substrates, valuable documents, and valuable goods are shown solely for illustrative purposes without limiting the scope of the present invention.

[0126]

[0125] Alternatively, the optical effect layer (OEL) may be generated, for example, on an auxiliary substrate such as a security thread, security stripe, foil, decal, window, or label, and as a result, may be adapted to be transferred to the security document in an independent step.

[0127]

[0126] A person skilled in the art can come up with several improvements for the above-described specific embodiments without departing from the gist of the present invention. Such improvements are included in the present invention.

[0128]

[0127] Furthermore, all documents cited throughout this specification are incorporated herein by reference in their entirety without omission.

Examples

[0129]

[0128] By using the magnetic assembly (x00) shown in FIGS. 6 to 8, non-spherical, particularly platelet-shaped optically variable magnetic pigment particles in the coating layer (x10) of the UV-curable screen printing ink described in Table 1 were oriented to produce the optical effect layer (OEL) shown in FIGS. 9B-1 to 9B-3. A square coating layer (x10) with a thickness of approximately 20 μm and dimensions of 35 mm × 35 mm was formed by manual screen printing using a T90 screen, and a UV-curable screen printing ink was applied to a black commercial paper (Gascogne Laminates M-cote 120) (x20). Subsequently, the magnetic orientation pattern of the platelet-shaped optically variable magnetic pigment particles thus obtained was, at least partially simultaneously with the orientation step (i.e., while the substrate (x20) having the coating layer (x10) of the UV-curable screen printing ink was still present in the magnetic field of the magnetic assembly (x00)), fixed by exposing the layer containing the pigment particles to UV curing using a UV-LED lamp (FireFlex type, 50 × 75 mm, 395 nm, 8W / cm 2 ) for approximately 0.5 seconds.

[0130]

Table 1

[0131] Comparative Example 1

[0129] The magnetic assembly (600) used to create the optical effect layer (OEL) of Comparative Example 1 on the substrate (620) is shown in FIGS. 6A to 6C. The magnetic assembly (600) was assumed to be configured to receive the substrate (620) in an orientation parallel to the first plane (P).

[0132]

[0130] The magnetic assembly (600) includes 41 first dipole magnets (631) embedded in a first square support matrix (632 1~41A first magnetic field generating device (630) including

[0133]

[0131] The first magnetic field generating device (630) includes nine parallel straight lines α i (α 1~9 ) and nine parallel straight lines β j (β 1~9 ), and the centers of 41 first dipole magnets (631 1~41 ) are respectively arranged at the intersections of the grids. The straight lines α i (α 1~9 ) are parallel to each other, and the straight lines β j (β 1~9 ) are parallel to each other. The straight line α i is perpendicular to the straight line β j . The nine straight lines α i (α 1~9 ) are equally spaced, and adjacent straight lines are separated by a distance (A7) of 2.5 mm. Five straight lines α i (α 1 / 3 / 5 / 7 / 9 ) include five first dipole magnets, and four straight lines α i (α 2 / 4 / 6 / 8 ) include four first dipole magnets, so that the total number of the first dipole magnets is 41 (631 1~41 ). The nine straight lines β i (β 1~9 ) are equally spaced, and adjacent straight lines are separated by a distance (A6) of 2.5 mm. As shown in FIGS. 6A and 6B, although the first dipole magnets (631 1~41 ) are respectively arranged at the intersections of the grids, some of the intersections of the grids do not include the first dipole magnets.

[0134]

[0132] The 41 first dipole magnets (631 1~41 ) are cylindrical, have dimensions of 2 mm (A4: diameter) × 2 mm (A5: length), and are made of NdFeB N45. All of the first dipole magnets (631 1~41 ) are magnetized in the respective length (A5) direction as indicated by the S→N arrows in Fig. 6A, with the magnetic axis being straight line α i (α 1~9 ) and oriented parallel to the surface of the substrate (620), all facing the same direction. The first magnetic field generating device (630) is such that the vector sum H1 thereof is substantially parallel to the surface of the substrate (620).

[0135]

[0133] The first square support matrix (632) of the first magnetic field generating device (630) has dimensions of 50 mm (A1) × 50 mm (A2) × 3 mm (A3), is made of polyoxymethylene (POM), and is provided with 41 depressions for holding the 41 first dipole magnets (631 1~41 ). By having the depressions have the same dimensions as the 41 first dipole magnets (631 1~41 ), the top surfaces of the 41 first dipole magnets (631 1~41 ) are made to be in the same plane as the top surface of the first square support matrix (632).

[0136]

[0134] The second dipole magnet (641) of the second magnetic field generating device (640) is a square dipole magnet, has dimensions of 30 mm (B4) × 30 mm (B5) × 2 mm (B3), and is made of NdFeB N52. The second dipole magnet (641) is such that the SN magnetic axis is substantially parallel to the surface of the substrate (620). The second magnetic field generating device (640) is such that the vector sum H2 (corresponding to the magnetic axis of the second dipole magnet (641)) is substantially parallel to the substrate (620).

[0137]

[0135] As shown in Fig. 6A, each straight line α i (α 1~9In addition to the vector sum H1 of the first magnetic field generating device (630) and the vector sum H2 of the second magnetic field generating device (640), the vector sum H1 of the first magnetic field generating device (630) and the vector sum H2 of the second magnetic field generating device (640) form an angle γ of 0° (i.e., the straight line α i (α 1~9 ) is parallel to H2).

[0138]

[0136] The second square support matrix (642) of the second magnetic field generating device (640) has dimensions of 50 mm (B1) × 50 mm (B2) × 2 mm (B3), is made of polyoxymethylene (POM), and is provided with depressions / holes for holding the second dipole magnet (641), and the depressions / holes have the same shape and dimensions as the second dipole magnet (641) (i.e., 30 mm (B4) × 30 mm (B5) × 2 mm (B3)), so that the uppermost surface and the lowermost surface of the second dipole magnet (641) are in the same plane as the uppermost surface and the lowermost surface of the second square support matrix (642).

[0139]

[0137] The distance (h1) between the upper surface of the first square support matrix (632) of the first magnetic field generating device (630) (the upper surfaces of 41 first dipole magnets (631 1~41 ) and the surface of the substrate (620) facing the magnetic assembly (600) is assumed to be 1.5 mm. The distance (h2) between the upper surface of the second dipole magnet (641) of the second magnetic field generating device (640) and the lowermost surface of the square support matrix (632) of the first magnetic field generating device (630) is assumed to be 0 mm. That is, the first magnetic field generating device (630) and the second magnetic field generating device (640) are in direct contact.

[0140]

[0138] FIG. 9B-1 shows the OEL as a result generated by the magnetic assembly (600) shown in FIGS. 6A-6C at various viewing angles with the substrate (620) tilted by -20° to +20°. The OEL thus obtained gives an optical impression in which a plurality of dark spots and a plurality of bright spots move, appear, and / or disappear only in a single direction (vertical direction) when the substrate having the OEL is tilted around two vertical axes, namely the horizontal / transverse axis and the vertical / longitudinal axis (no change when the substrate is tilted around the horizontal / transverse axis).

[0141] Example 1

[0139] The magnetic assembly (700) used to create the optical effect layer (OEL) of Example 1 on the substrate (720) is shown in FIGS. 7A and 7B. The magnetic assembly (700) was configured to receive the substrate (720) in an orientation parallel to the first plane (P).

[0142]

[0140] The magnetic assembly (700) includes a first magnetic field generating device (730) having 41 first dipole magnets (731 1~41 ) embedded in a first square support matrix (732), and a second magnetic field generating device (740) having second dipole magnets (741) embedded in a second square support matrix (742). The second magnetic field generating device (740) is disposed below the first magnetic field generating device (730), and the first magnetic field generating device (730) is disposed between the substrate (720) having the coating layer (710) and the second magnetic field generating device (740). The first magnetic field generating device (730) and the second magnetic field generating device (740) are centered with respect to each other.

[0143]

[0141] The first magnetic field generating device (730) was assumed to be the same as that described with respect to Comparative Example C1.

[0144]

[0142] Second magnetic field generating device (740) The second dipole magnet (741) is a square-shaped dipole magnet with dimensions of 30 mm (B4) × 30 mm (B5) × 4 mm (B3) and is made of NdFeB N30. The second dipole magnet (741) is such that the SN magnetic axis is substantially parallel to the substrate (720). The second magnetic field generating device (740) is such that its vector sum H2 (corresponding to the magnetic axis of the only second dipole magnet (741)) is substantially parallel to the substrate (720).

[0145]

[0143] As shown in Fig. 7A, each straight line α i (α 1~9 ) and in addition to the vector sum H2 of the second magnetic field generating device (740), the vector sum H1 of the first magnetic field generating device (730) and the vector sum H2 of the second magnetic field generating device (740) form an angle γ of 60°.

[0146]

[0144] The second square support matrix (742) of the second magnetic field generating device (740) has dimensions of 50 mm (B1) × 50 mm (B2) × 4 mm (B3), is made of polyoxymethylene (POM), and is provided with a depression / hole for holding the second dipole magnet (741), and the depression / hole has the same shape and dimensions as the second dipole magnet (741) (i.e., 30 mm (B4) × 30 mm (B5) × 4 mm (B3)), so that the top and bottom surfaces of the second dipole magnet (741) are in the same plane as the top and bottom surfaces of the second square support matrix (742).

[0147]

[0145] The upper surface of the first square support matrix (732) of the first magnetic field generating device (730) (41 first dipole magnets (731 1~41) is also compatible with the upper surface), and the distance (h1) between the surface of the substrate (720) facing the magnetic assembly (700) is assumed to be 1.5 mm. The distance (h2) between the upper surface of the second dipole magnet (741) of the second magnetic field generating device (740) and the lowermost surface of the square support matrix (732) of the first magnetic field generating device (730) is assumed to be 0 mm. That is, the first magnetic field generating device (730) and the second magnetic field generating device (740) are in direct contact.

[0148]

[0146] FIG. 9B-2 shows the OEL as a result generated by the magnetic assembly (700) shown in FIGS. 7A and 7B. The OEL thus obtained gives an optical impression in which a plurality of dark spots and a plurality of bright spots move, appear, and / or disappear in the diagonal direction with respect to the vertical and horizontal tilt directions when the substrate having the OEL is tilted around two vertical axes, i.e., the horizontal / transverse axis and the vertical / longitudinal axis.

[0149] Example 2

[0147] The magnetic assembly (800) used to create the optical effect layer (OEL) of Example 2 on the substrate (820) is shown in FIGS. 8A and 8B. The magnetic assembly (800) is configured to receive the substrate (820) in an orientation parallel to the first plane (P).

[0150]

[0148] The magnetic assembly (800) includes a first magnetic field generating device (830) having 41 first dipole magnets (831 1~41 ) embedded in a first square support matrix (832), and two second dipole magnets (8411, 841 -2)That is, it is provided with a second magnetic field generating device (840) including a first second dipole magnet (8411) and a second second dipole magnet (8412), and the first second dipole magnet (8411) is disposed above the second second dipole magnet (8412), and the second magnetic field generating device (840) is disposed below the first magnetic field generating device (830), and the first magnetic field generating device (830) is disposed between the substrate (820) having the coating layer (810) and the second magnetic field generating device (840). The first magnetic field generating device (830) and the second magnetic field generating device (840) are essentially centered on each other. The two second dipole magnets (8411, 841 -2 ) are centered on each other.

[0151]

[0149] The first magnetic field generating device (830) is assumed to be the same as that described for Comparative Example C1.

[0152]

[0150] The second magnetic field generating device (840) includes two second dipole magnets (8411, 841 -2 ) which are square dipole magnets, have dimensions of 30 mm (B4) × 30 mm (B5) × 2 mm (1 / 2 B3), and are made of NdFeB N30. The two second dipole magnets (8411, 841 -2 ) are such that the SN magnetic axis is substantially parallel to the substrate (820). As shown in FIG. 8, the magnetic axis of the first second dipole magnet (8411) is perpendicular to the magnetic axis of the second second dipole magnet (8412).

[0153]

[0151] The second magnetic field generating device (840) has two depressions for holding the two second dipole magnets (8411, 8412) that are the two second dipole magnets (8411, 841 -2Except for setting the dimension B3 to 4 mm (i.e., the depth of the depression) so as to have the same shape and dimensions as (i.e., 30 mm (B4) × 30 mm (B5) × 4 mm (B3)), it is provided with the same second square-shaped support matrix (842) as that used in Comparative Example C1, so that the top surface of the first second dipole magnet (8411) is in the same plane as the top surface of the second square-shaped support matrix (842), and two second dipole magnets (8411, 841 -2 ) are integrally stacked so that their centers coincide and they are in direct contact with each other. The second magnetic field generating device (840) is configured such that the vector sum H2 (the result of adding the magnetic axes of the first second dipole magnet (8411) and the second second dipole magnet (8412)) is substantially parallel to the substrate (820).

[0154]

[0152] As shown in FIG. 8, each straight line α i (α 1~9 ) and in addition to the vector sum H2 of the second magnetic field generating device (840), the vector sum H1 of the first magnetic field generating device (830) and the vector sum H2 of the second magnetic field generating device (840) are set to form an angle γ of 45°.

[0155]

[0153] The distance (h1) between the upper surface of the first square-shaped support matrix (832) of the first magnetic field generating device (830) (corresponding to the upper surfaces of 41 first dipole magnets (831 1~41 )) and the surface of the substrate (820) facing the magnetic assembly (800) is set to 1.5 mm. The distance (h2) between the upper surface of the second dipole magnet (841) of the second magnetic field generating device (840) and the lowermost surface of the square-shaped support matrix (832) of the first magnetic field generating device (830) is set to 0 mm. That is, the first magnetic field generating device (830) and the second magnetic field generating device (840) are in direct contact with each other.

[0156]

[0154] FIG. 9B-3 shows the OEL as a result generated by the magnetic assembly (800) shown in FIG. 8. The OEL obtained in this way gives an optical impression in which a plurality of dark spots and a plurality of bright spots move, appear, and / or disappear in a diagonal direction with respect to the vertical and horizontal tilt directions when the substrate having the OEL is tilted around two vertical axes, namely the horizontal / transverse axis and the vertical / longitudinal axis.

Claims

1. A magnetic assembly (x00) for generating an optical effect layer (OEL) on a substrate (x20), the magnetic assembly (x00) being configured to receive the substrate (x20) in an orientation in which a first plane (P) corresponding to the surface of the substrate (x20) and at least a part of the magnetic assembly (x00) are parallel, a) A first magnetic field generating device (x30) comprising at least four first dipole magnets (x31) which are spaced apart from each other, with their N - poles facing the same direction and their magnetic axes oriented substantially parallel to the first plane (P), Each of the first dipole magnets (x31) is located at the intersection of 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 lines α ｉ and β ｊ form a grid, At least two 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 axis of the first dipole magnet (x31) is substantially parallel to the straight line α ｉ and is oriented substantially parallel thereto, wherein the first dipole magnets (x31) of the first magnetic field generating device (x30) are partially or wholly embedded in a first support matrix (x32), the first magnetic field generating device (x30), b) A second magnetic field generating device (x40) comprising a single second dipole magnet (x41) with its magnetic axis oriented substantially parallel to the first plane (P) and being partially or wholly embedded in a second support matrix (x42), wherein the second magnetic field generating device (x40) is disposed below the first magnetic field generating device (x30), Each straight line α ｉ and the magnetic axes of the single second dipole magnet (x41) are substantially non-parallel and substantially non-perpendicular to each other, the second magnetic field generating device (x40), The magnetic assembly (x00) comprising.

2. A magnetic assembly (x00) for generating an optical effect layer (OEL) on a substrate (x20), the magnetic assembly (x00) being configured to receive the substrate (x20) in an orientation in which a first plane (P) corresponding to the surface of the substrate (x20) and at least a part of the magnetic assembly (x00) are parallel, a) A first magnetic field generating device (x30) comprising at least four first dipole magnets (x31) which are spaced apart from each other, with their N - poles facing the same direction and their magnetic axes oriented substantially parallel to the first plane (P), wherein each of the first dipole magnets (x31) is disposed at the intersection of at least two substantially parallel straight lines αi (i = 1, 2,...) and at least two substantially parallel straight lines βj (j = 1, 2,...), and the straight lines αi and βj form a grid, at least two of the first dipole magnets (x31) are disposed on one of the straight lines αi, and at least two other first dipole magnets (x31) are disposed on another one of the straight lines αi, the magnetic axes of the first dipole magnets (x31) being oriented substantially parallel to the substantially parallel straight lines αi, wherein the first dipole magnet (x31) of the first magnetic field generating device (x30) is partially or entirely embedded in a first support matrix (x32), a first magnetic field generating device (x30), b) a second magnetic field generating device (x40) comprising a plurality of second dipole magnets (x41) whose magnetic axes are oriented substantially parallel to the first plane (P) and which are partially or entirely embedded in a second support matrix (x42), wherein the plurality of second dipole magnets (x41) comprises two second dipole magnets (x41), one of the two second dipole magnets being disposed on top of the other of the second dipole magnets (x41), and the N poles of each of the two second dipole magnets (x41) facing in different directions, wherein the second magnetic field generating device (x40) is disposed below the first magnetic field generating device (x30), wherein the vector sum H of each straight line αi and the magnetic axes of the plurality of second dipole magnets (x41) is substantially non-parallel and substantially non-perpendicular to each other, a second magnetic field generating device (x40), a magnetic assembly (x00) comprising:

3. Each straight line α ｉ The magnetic assembly (x00) according to claim 1, wherein the magnetic axis of the single second dipole magnet (x41) forms 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°.

4. The magnetic assembly (x00) according to claim 2, wherein the vector sum H of each straight line αi and the magnetic axes of the plurality of second dipole magnets (x41) forms an angle γ in the range of 20° to 70°, 110° to 160°, 200° to 250°, or 290° to 340°.

5. The magnetic assembly (x00) according to any one of claims 1 to 4, further comprising one or more third dipole magnets (x33) which are partially or entirely embedded in the first support matrix (x32), whose magnetic axes are oriented substantially parallel to the surface of the substrate (x20), and whose N poles face in a direction different from the direction of the N pole of the first dipole magnet (x31).

6. The first magnetic field generating device (x30) includes at least nine first dipole magnets (x31), and the grid includes at least three of the substantially parallel straight lines α ｉ and at least three of the substantially parallel straight lines β ｊ At least three first dipole magnets (x31) are disposed on one of the straight lines α ｉ At least three first dipole magnets (x31) are disposed on another one of the straight lines α ｉ At least three other first dipole magnets (x31) are disposed on yet another one of the straight lines α ｉ The magnetic assembly (x00) according to any one of claims 1 to 5, wherein the magnetic assembly (x00) is disposed on yet another one of the straight lines α

7. Each straight line α ｉ and / or each straight line β ｊ On which the adjacent first dipole magnets (x31) are separated from each other by the same distance, the magnetic assembly (x00) according to any one of claims 1 to 6.

8. Use of the magnetic assembly (x00) according to any one of claims 1 to 7 for generating an optical effect layer (OEL) on a substrate.

9. A printing apparatus comprising a rotary magnetic cylinder comprising at least one of the magnetic assemblies (x00) according to any one of claims 1 to 7, or a printing apparatus comprising a flatbed printing unit comprising at least one of the magnetic assemblies (x00) according to any one of claims 1 to 7.

10. A process for generating an optical effect layer (OEL) on a substrate (x20), i) applying a radiation-curable coating composition in a first state, which comprises a plurality of non-spherical magnetic or magnetizable pigment particles and forms a coating layer (x10), onto the surface of a substrate (x20); ii) exposing the radiation-curable coating composition to a magnetic field of the fixed magnetic assembly (x00) according to any one of claims 1 to 7 so as to orient at least a part 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 magnetizable pigment particles in their respective adopted positions and orientations; A process comprising the above steps.

11. The process according to claim 10, wherein step iii) is carried out by ultraviolet / visible light radiation curing.

12. The process according to claim 11, wherein step iii) is carried out at least partially simultaneously with step ii).

13. The process according to any one of claims 10 to 12, wherein at least a part of the plurality of non-spherical magnetic or magnetizable pigment particles is constituted by non-spherical optically variable magnetic or magnetizable pigment particles.

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

15. The process according to any one of claims 10 to 14, further comprising a step of exposing the coating layer (x10) to a dynamic magnetic field of a device so as to biaxially orient at least a part of the non-spherical magnetic or magnetizable pigment particles, which occurs before or at least partially simultaneously with step ii) and before step iii).

Images