Processes for producing optical effects layers

Abstract

This invention relates to the field of protecting secure documents, such as banknotes and identity documents, from counterfeiting and illegal copying. In particular, the invention provides a method for producing an optical effect layer (OEL) comprising at least a first pattern and a second pattern that are at least partially adjacent to each other, each pattern independently comprising magnetically oriented sheet-like magnetic or magnetizable pigment particles.

Description

(19) State Intellectual Property Office (12) Invention Patent Application (10) Application Publication Number (43) Application Publication Date (21) Application Number 202480079858.3 (22) Application Date 2024.12.18 (30) Priority Data 23218639.5 2023.12.20 EP (85) PCT International Application Entering National Phase Date 2026.06.16 (86) PCT International Application Application Data PCT / EP2024 / 087125 2024.12.18 (87) PCT International Application Publication Data WO2025 / 132601 EN 2025.06.26 (71) Applicant Sikbai Holding Ltd. Address Switzerland (72) Inventors N. Benninger CA. Desplanade A. Caligari (74) Patent Agency Beijing Linda Liu Intellectual Property Agency (General Partnership) 11277 Patent Attorney Li Maojia Duan Ran (51) Int.Cl. B05D 3 / 00 (2006.01) B05D 5 / 06 (2006.01) (54) Invention Title Method for Generating Optical Effect Layer (57) Abstract This invention relates to the field of protecting secure documents such as banknotes and identity documents from counterfeiting and illegal copying. In particular, the invention provides a method for generating an optical effect layer (OEL), said optical effect layer (OEL) comprising at least a first pattern and a second pattern that are at least partially adjacent to each other, each of said patterns independently comprising magnetically oriented sheet-like magnetic or magnetizable pigment particles. Claims 2 pages, Description 43 pages, Drawings 5 ​​pages, CN 122422064 A 2026.07.17 CN 1 22 42 20 64 A 1. A method for producing an optical effect layer (OEL) on a substrate (x10) having a first side and a second side, the optical effect layer (OEL) comprising a first pattern and a second pattern, the first pattern comprising sheet-like magnetic or magnetizable pigment particles oriented according to a first magnetic pattern orientation, the second pattern comprising sheet-like magnetic or magnetizable pigment particles oriented according to a second magnetic pattern orientation, the method comprising: a first set of steps, comprising: a') applying a first radiation-curable coating composition comprising sheet-like magnetic or magnetizable pigment particles, preferably a first UV-Vis curable coating composition, to a first side of the substrate (x10) to form a first coating (x20') on the first side of the substrate (x10), the coating composition being in a first state, b') step a The first radiation-curable coating composition is exposed to the magnetic field of the magnetic component (x30') to magnetically orient at least a portion of the sheet-like magnetic or magnetizable pigment particles.A magnetic component (x30') is located on a second side of a substrate (x10); c') the radiation-curable coating composition of step b') is at least partially cured to a second state to fix the flake-like magnetic or magnetizable pigment particles in their adopted positions and orientations, and to produce a first pattern; and a second set of steps, comprising: a'') applying a second radiation-curable coating composition, preferably a second UV-Vis curable coating composition, containing flake-like magnetic or magnetizable pigment particles, to a second side of a substrate (x10) in a registration manner to form a second coating (x20'') on the second side of the substrate (x10), the coating composition being in a first state, and at least a portion of the second coating (x20'') being adjacent to at least a portion of the first coating (x20'); b'') exposing the second radiation-curable coating composition of step a'') to the magnetic field of the magnetic component (x30''), the magnetic component (x30'') being used in step b') with the magnetic component (x30'') in the first state. The magnetic field in step b'') is the same as and located on the first side of the substrate (x10), and the magnetic field in step b'') is substantially the same as the magnetic field in step b''), thereby causing at least a portion of the sheet-like magnetic or magnetizable pigment particles to be magnetically oriented; and c'') at least partially cures the second radiation-curable coating composition of step b'') to a second state to fix the sheet-like magnetic or magnetizable pigment particles in their adopted positions and orientations, and to produce a second pattern, wherein the magnetic field of the magnetic component (x30') in step b'') and the magnetic field of the magnetic component (x30'') in step b'') are mirror symmetrical with respect to a plane parallel to the substrate (x10), wherein at least a portion of the second coating (x20'') and the first coating (x20') have their projections on each side of the substrate (x10), and at least a portion of the second coating (x20'') and the first coating (x20') are adjacent to at least a portion of the first coating (x20'), which means that their projections on each side of the substrate (x10) are continuous. 2. The method of claim 1, wherein at least one of step b') and step b'') is a one-step magnetic orientation step of uniaxially orienting the sheet-like magnetic or magnetizable pigment particles, or a two-step orientation step comprising a first orientation step of biaxially orienting the sheet-like magnetic or magnetizable pigment particles, followed by a second orientation step of reorienting the sheet-like magnetic or magnetizable pigment particles. 3. The method of claim 2, wherein step b') and / or step b'') are independently two-step orientation steps comprising a first orientation step of biaxially orienting the sheet-like magnetic or magnetizable pigment particles, followed by a second orientation step of reorienting the sheet-like magnetic or magnetizable pigment particles. 4. The method of any one of claims 1 to 3, wherein step b') and / or step b'') is a two-step orientation step comprising a first orientation step and a subsequent second orientation step.The first orientation step biaxially oriented the sheet-like magnetic or magnetizable pigment particles, and the second orientation step reorienting the sheet-like magnetic or magnetizable pigment particles, wherein the first orientation step is performed to biaxially oriented at least a portion of the sheet-like magnetic or magnetizable pigment particles such that i) both their X-axis and Y-axis are substantially parallel to the substrate (x10) surface, or ii) a first axis in the XY plane is substantially parallel to the substrate (x10) surface, and a second axis is perpendicular to the first axis at a substantially non-zero elevation angle to the substrate (x10) surface, or iii) their XY plane is parallel to an imaginary spherical surface. 5. The method according to any one of claims 1 to 4, wherein the first radiation-curable coating composition and the second radiation-curable coating composition exhibit different colors. 6. The method according to any one of claims 1 to 5, wherein steps a') and a'') are performed independently by a printing method selected from the group consisting of screen printing, rotary gravure printing, flexographic printing, and gravure printing, preferably by screen printing. 7. The method according to any one of claims 1 to 6, wherein steps c') and b') are performed simultaneously and / or steps c'') and b'') are performed simultaneously. 8. The method according to claim 7, wherein step c') is performed by exposing an LED curing unit (x50) to UV-Vis light radiation, and / or step c'') is performed by exposing an LED curing unit (x50) to UV-Vis light radiation. 9. The method according to any one of claims 1 to 8, wherein at least a portion of the sheet-like magnetic or magnetizable pigment particles is composed of sheet-like optically variable magnetic or magnetizable pigment particles. 10. The method according to any one of claims 1 to 9, wherein the substrate (x10) is selected from the group consisting of: paper or other fibrous materials, paper-containing materials, glass, metal, ceramics, polymers, metallized polymers, at least partially opaque polymers, composite materials, and mixtures or combinations thereof. 11. The method according to claim 10, wherein the substrate (x10) is a transparent substrate. 12. The method according to any one of claims 1 to 11, wherein the substrate (x10) comprises a printed pattern, preferably an offset printed pattern, and wherein at least one of the radiation-curable coating compositions of steps a') and a'') is at least partially applied to the printed pattern. 13. The method according to any one of claims 1 to 12, wherein the first coating (x20') and the second coating (x20'') are registered within ±1 mm, preferably ±0.5 mm, more preferably ±0.2 mm. 14. The method according to any one of claims 1 to 13, wherein the method is a continuous method using a single machine."Continuous" means that the second set of steps is performed directly after the first set of steps, or, in the case that the method includes a third set of steps, the third set of steps is performed directly after the second set of steps. Claims 2 / 2 Page 3 CN 122422064 A Method for Generating Optical Effect Layers Technical Field

[0001] The present invention relates to the field of methods for generating optical effect layers (OELs) comprising sheet-like magnetic or magnetizable pigment particles with magnetic orientation. In particular, the present invention provides a method for magnetically orienting sheet-like magnetic or magnetizable pigment particles in more than one coating to generate an OEL, and the use of the OEL as an anti-counterfeiting means and for decorative purposes on secure documents or secure articles. Background Art

[0002] It is known in the art to use inks, compositions, coatings or layers containing oriented magnetic or magnetizable pigment particles, and in particular optically variable magnetic or magnetizable pigment particles, to generate security elements, for example, in the field of secure documents. Coatings or layers containing oriented magnetic or magnetizable pigment particles are disclosed, for example, in US 2,570,856; US 3,676,273; US 3,791,864; US 5,630,877 and US 5,364,689. Coatings or layers containing oriented magnetic color-changing pigment particles are disclosed in WO 2002 / 090002 A2 and WO 2005 / 002866 A1, resulting in particularly attractive optical effects that can be used to protect secure documents.

[0003] For example, security features for secure documents can generally be classified as “covert” security features on one hand and “overt” security features on the other hand. The protection provided by implicit security features relies on the principle that such features are difficult to detect, typically requiring specialized equipment and knowledge for detection, while “explicit” security features rely on the concept that can be easily detected with unassisted human senses; for example, such features can be visible and / or detectable via tactile senses, while still being difficult to produce and / or reproduce. However, the effectiveness of explicit security features depends largely on their ease of identification as security features.

[0004] Magnetic or magnetizable pigment particles in printing inks or coatings allow for the induction of localized orientation of magnetic or magnetizable pigment particles in an uncured (i.e., wet) coating by applying a correspondingly structured magnetic field, thereby hardening the coating.To generate magnetically induced images, designs, and / or patterns (also referred to in the art as "optical effect layers (OELs)"). The result is a fixed and stable magnetically induced image, design, or pattern. Materials and techniques for orienting magnetic or magnetizable pigment particles in a coating composition are known. The magnetically induced image discussed can only be generated by simultaneously utilizing magnetic or magnetizable pigment particles or corresponding inks and specific techniques for printing said inks and orienting said pigments in printed inks.

[0005] For the purpose of optimizing and improving the anti-counterfeiting properties of secure documents, particularly banknotes, conspicuous and complex magnetically induced images and optical effect layers (OELs) have been developed. The OELs are obtained by using specific magnetic components and advantageously exhibit a dynamic appearance when tilted. Examples of such dynamic OELs include reflective area strips that move with the tilt of the OEL, annular bodies that move with the tilt of the OEL, annular bodies with changing shapes as the OEL tilts, and bright and dark areas that move with the tilt of the OEL. WO 2012 / 104098 A1 discloses an OEL containing more than one magnetically induced image. WO 2012 / 104098 A1 discloses an OEL comprising two regions, each region exhibiting a reflective area bar that moves as the OEL tilts, one of the bars moving away from the observer as the OEL tilts, and the other of the bars moving towards the observer as the OEL tilts.

[0006] A method for producing an OEL comprising at least two regions made of a single cured layer includes: i) applying a UV-curable ink comprising magnetic or magnetizable particles to a substrate to form a coating; ii) exposing the coating to a magnetic field of a magnetic field generating device, thereby orienting the pigment particles; iii) curing one or more first regions of the coating to a second state to fix the magnetic or magnetizable particles in their adopted positions and orientations, said curing being performed by selectively irradiating the coating with a radiation source; iv) exposing the coating to a magnetic field of the magnetic field generating device, thereby reorienting the magnetic or magnetizable particles contained in the coating that are still in a wet liquid state and have not yet cured due to the selective curing of step iii); and v) curing the coating to fix the magnetic or magnetizable particles in their newly adopted positions and orientations.

[0007] In the field of curing coating or ink compositions used to produce OEL with the aid of a UV radiation source, the characteristics and construction of the UV radiation source and the precise exposure conditions of the coating or ink composition to the UV radiation source are known to be crucial for obtaining high-resolution images and rapid curing of the composition. However, known methods for selective curing suffer from several drawbacks.

[0008] A method is disclosed that involves using a fixed photomask,The fixed photomask includes one or more gaps corresponding to a pattern to be formed as part of an image on a coating carried by a fixed substrate. However, the disclosed method may result in potential shadowing effects on the coating due to the following constraints: a) the photomask may not contact the uncured ink layer, but must be positioned at a distance from it, and b) the UV source must be an extended light source. All of these result in low-resolution images and require low printing speeds because the substrate, photomask, and UV source need to be held in fixed relative positions during exposure time. Alternatively, a fixed photomask may be used with a coating carried by a moving substrate. The method may also result in shadowing effects and / or image blurring on the coating due to moving the substrate at industrial speeds during exposure to irradiation, without any possibility of implementing variable image information during printing. Alternatively, a moving photomask may be used with a moving substrate. However, the method may also result in shadowing effects on the coating, resulting in low-resolution imaging, and is highly complex to implement.

[0009] Another method uses a laser beam. However, it is known that this method requires highly specialized equipment and is costly.

[0010] Another method uses an array of LED light-emitting diodes (LEDs). However, this method may suffer from unnecessarily low light density, resulting in longer curing times and reduced print performance.

[0011] A method for producing an OEL comprising at least two regions made of two different inks involves passing through a printing press several times, as disclosed in EP 2 433 798 B1. The method includes i) applying a first UV-curable ink comprising magnetic or magnetizable pigment particles to a substrate to form a first coating; ii) exposing the first coating to a magnetic field of a magnetic field generating device to orient the pigment particles; iii) curing the first coating to a second state to fix the pigment particles in their adopted positions and orientations; iv) removing the substrate carrying the first coating from the printing press and reintroducing it into the printing press to v) applying a second UV-curable ink comprising magnetic or magnetizable pigment particles to form a second coating; vi) exposing the second coating to a magnetic field of a magnetic field generating device to orient the pigment particles; and vii) curing the second coating to a second state to fix the pigment particles in their adopted positions and orientations. Because it needs to pass through the printing press several times, the method requires tedious and time-consuming alignment of the substrate before the second application step. Since this alignment is very difficult to control and achieve, a large number of optical effect layers suffer from poor and unacceptable registration, resulting in significant waste of substrate and ink.

[0012] Alternatively, an OEL comprising at least two regions made of two different inks can be produced by a method comprising: i) applying a first UV-curable ink containing magnetic or magnetizable pigment particles onto the substrate,To form a first coating; ii) to apply a second UV-curable ink containing magnetic or magnetizable pigment particles to a substrate to form a second coating; iii) to expose the coating to the magnetic field of a magnetic field generating device, thereby orienting the pigment particles; iv) to cure the first and second coatings to a second state to fix the pigment particles in their adopted positions and orientations. However, the method is extremely complex to implement because it means printing two inks in liquid state and requires printing the second ink while the first ink is still liquid without interfering with the first ink, thus only allowing the preparation of spaced-apart coatings.

[0013] There is still a need for improved and controlled methods for producing eye-catching optical effect layers (OEL) for security printing presses at industrial speeds, wherein the OEL thus produced is easily certified by ordinary people, while the method is very difficult for counterfeiters and the illegal market to implement in large-scale production. Summary of the Invention

[0014] Therefore, the object of the present invention is to overcome the deficiencies of the prior art as described above. This is achieved by providing a method for forming an optical effect layer (OEL) on a substrate (x10), the OEL comprising a first pattern and a second pattern, the first pattern comprising sheet-like magnetic or magnetizable pigment particles with a magnetic orientation according to a first magnetic pattern orientation, and the second pattern comprising sheet-like magnetic or magnetizable pigment particles with a magnetic orientation according to a second magnetic pattern orientation, the method comprising:

[0015] a first set of steps comprising:

[0016] a') applying a first radiation-curable coating composition, preferably a first UV-Vis curable coating composition, comprising sheet-like magnetic or magnetizable pigment particles to a first side of the substrate (x10) to form a first coating (x20') on the first side of the substrate (x10), the coating composition being in a first state,

[0017] b') Exposing the first radiation-curable coating composition of step a') to the magnetic field of the magnetic component (x30') to magnetically orient at least a portion of the sheet-like magnetic or magnetizable pigment particles, the magnetic component (x30') being located on a second side of the substrate (x10);

[0018] c') At least partially curing the radiation-curable coating composition of step b') to a second state to fix the sheet-like magnetic or magnetizable pigment particles in their adopted positions and orientations, and to produce a first pattern; and

[0019] a second set of steps, comprising:

[0020] a'') Applying a second radiation-curable coating composition, preferably a second UV-Vis curable coating composition, containing sheet-like magnetic or magnetizable pigment particles in a registration manner to a second side of the substrate (x10) to form a second coating (x20'') on the second side of the substrate (x10), the coating composition being in a first state,And at least a portion of the second coating (x20'') is adjacent to at least a portion of the first coating (x20'),

[0021] b'') exposing the second radiation-curable coating composition of step a'') to the magnetic field of the magnetic component (x30''), the magnetic component (x30'') being the same as the magnetic component (x30') used in step b') and located on the first side of the substrate (x10), and the magnetic field in step b'') being substantially the same as the magnetic field in step b'), thereby causing at least a portion of the sheet-like magnetic or magnetizable pigment particles to be magnetically oriented; and

[0022] c'') at least partially curing the second radiation-curable coating composition of step b'') to a second state to fix the sheet-like magnetic or magnetizable pigment particles in their adopted positions and orientations, and to produce a second pattern,

[0023] wherein the magnetic field of the magnetic component (x30') in step b') and the magnetic field of the magnetic component (x30'') in step b'') are symmetrical with respect to a mirror plane parallel to the substrate (x10).

[0024] This document also describes a method for generating an OEL comprising a first pattern, a second pattern, and a third pattern, the first pattern comprising sheet-like magnetic or magnetizable pigment particles oriented according to a first magnetic pattern as described herein, the second pattern comprising sheet-like magnetic or magnetizable pigment particles oriented according to a second magnetic pattern as described herein, and the third pattern comprising sheet-like magnetic or magnetizable pigment particles oriented according to a third magnetic pattern, wherein the first, second, and third magnetic patterns are different from each other, wherein at least a portion of the third pattern is adjacent to and properly registered with at least a portion of the first pattern and / or adjacent to and properly registered with at least a portion of the second pattern (i.e., the third pattern is at least partially adjacent to and properly registered with the first pattern and / or at least partially adjacent to and properly registered with the second pattern), and wherein the method comprises the first set of steps a'), b'), and c'), the second set of steps a''), b''), and c''), and the third set of steps a'''), as described herein. (Specification 3 / 43 pages 6 CN 122422064 A) b''') and c'''), the third step a''') is performed after and consecutively with step c''').

[0025] This document also describes optical effect layers (OELs) and security documents produced by the methods described herein, as well as decorative elements and objects comprising one or more optical OELs described herein.

[0026] This document also describes a method of manufacturing a security document or decorative element or object, comprising a) providing a security document or decorative element or object, and b) providing an optical effect layer obtained by the methods described herein,This allows it to be contained in secure documents or decorative elements or objects.

[0027] The present invention provides a method that advantageously allows the manufacture of a striking optical effect layer (OEL) that is easily authenticated by the average person. In particular and thanks to the use of a magnetic field substantially symmetrical with respect to a mirror parallel to the substrate (x10) in steps b') and b''), the resulting OEL containing first and second patterns with specific magnetic orientation patterns as described herein exhibits a continuous effect at a first viewing angle, the effect originating from the first and second magnetic patterns and comprising a continuous image extending continuously from the first pattern to the second pattern, wherein the effect splits when tilted and recombines when tilted back to the first viewing angle to form the same effect; this highly dynamic effect, caused not only by the perfect registration of the applied first and second patterns but also by the perfect registration of the effect originating from the first and second magnetic patterns, allows for easy authentication due to the continuity of the effect at an angle and due to the splitting and recombination at tilt, while combining a high level of anti-counterfeiting due to the complex registration of adjacent patterns. Thanks to the controlled method described herein and the optical effect layer (OEL) thus obtained, the authentication of the explicit security features allows observers to easily distinguish between counterfeits (visually similar results obtained by different methods) and inferior copies (obtained by the same method but less well controlled).

[0028] Figures 1-9 are provided, in which the invention is schematically illustrated and not drawn to scale. The optical effect layer (OEL) and its generation described herein are now described in more detail with reference to the accompanying drawings and specific embodiments, wherein

[0029] FIG1 schematically illustrates a combination of a first pattern comprising sheet-like magnetic or magnetizable pigment particles oriented according to a first magnetic pattern and a second pattern comprising sheet-like magnetic or magnetizable pigment particles oriented according to a second magnetic pattern, wherein the first and second patterns are on opposite sides of a substrate (110); furthermore, FIG1 schematically illustrates the OEL, wherein the first pattern (120') comprises sheet-like magnetic or magnetizable pigment particles (P') oriented according to the first magnetic pattern, and the second pattern (120'') comprises sheet-like magnetic or magnetizable pigment particles (P'') oriented according to the second magnetic pattern, wherein the first and second magnetic patterns are substantially symmetrical with respect to a mirror surface parallel to the substrate (110).

[0030] FIG2 schematically illustrates sheet-like pigment particles.

[0031] FIG3 schematically illustrates a method for producing an optical effect layer (OEL) on a substrate (310) including a first set of steps (1) and a second set of steps (2) according to the invention, wherein both alignment steps b') and b'') comprise an alignment step,

[0032] wherein the substrate (310) bearing a first coating (320') obtained by screen printing (340') (step a')) on its first side is exposed to the magnetic field of the magnetic component (330'),To achieve magnetic orientation of at least a portion of the sheet-like magnetic or magnetizable pigment particles (step b'), and wherein the first coating (320') is at least partially cured with the first curing unit (350') (step c'), wherein the magnetic component (330') is located on the second side of the substrate (i.e., the side without the first coating (320')), and wherein

[0033] after and continuously thereafter in step c'), the substrate (310) bearing the second coating (320'') obtained by screen printing (340'') (step a'') on its second side is exposed to the magnetic field of the magnetic component (330'') to achieve magnetic orientation of at least a portion of the sheet-like magnetic or magnetizable pigment particles (step b''), wherein the second coating (320'') is at least partially cured with the second curing unit (350'') (step c''), wherein the magnetic component (330'') is located on the first side of the substrate (i.e., the side without the first coating (320')), and wherein

[0033] after and continuously thereafter in step c'), the substrate (310) bearing the second coating (320'') obtained by screen printing (340'') (step a'') is exposed to the magnetic field of the magnetic component (330'') to achieve magnetic orientation of at least a portion of the sheet-like magnetic or magnetizable pigment particles (step b''), wherein the second coating (320'') is at least partially cured with the second curing unit (350'') (step c'')), wherein the magnetic component (330'') is located on the first side of the substrate (i.e., the side without the first coating (320')). On one side of the first coating (320') in the cured state.

[0034] Figures 4A-1 and 4A-2 show industrial one-step magnetic orientation step b) (that is, steps b') and b'')), wherein the coating (420) is exposed to the magnetic field of the magnetic component (430) mounted on a rotating magnetic cylinder, wherein the coating (420) faces the environment (Figure 4A-1), or is placed outside the rotating cylinder, wherein the coating (420) faces the magnetic component (430) (Figure 4A-2).

[0035] Figure 4B shows industrial one-step magnetic orientation step b) (that is, steps b') and / or b'')), wherein the coating (420) is exposed to the combined magnetic field of the first magnetic component (430-a) and the second magnetic component (430-b), wherein the first magnetic component (430-a) is mounted on a rotating magnetic cylinder, and the second magnetic component (430-b) is placed outside the rotating magnetic cylinder.

[0036] FIG5-1 schematically illustrates a method for producing an optical effect layer (OEL) on a substrate (510) including a first set of steps (1) and a second set of steps (2) according to the invention, wherein the method is used in the embodiments E1-E4 provided therein, and wherein both the orientation steps b') and b'') comprise two magnetic orientation steps,

[0037] wherein the substrate (510) bearing a first coating (520') obtained by screen printing (540') (step a')) on its first side is first exposed to a first magnetic field of a magnetic component (530'-a) (step b'-1)), and then subsequently exposed to a second magnetic field of a magnetic component (530'-b) (step b'-2) to magnetically orient at least a portion of the sheet-like magnetic or magnetizable pigment particles (step b')).And wherein the coating (520') is at least partially cured with the first curing unit (550') (step c') and wherein the magnetic components (530'-a and 530'-b) are located on the second side of the substrate (i.e., the side without the first coating (520')),

[0038] and wherein

[0039] after and consecutively thereafter in step c'), the substrate (510) bearing the second coating (520'') obtained by screen printing (540'') (step a'') on its second side is first exposed to the magnetic field of the first magnetic field of the magnetic component (530''-a) (step b''-1) and then subsequently exposed to the magnetic field of the second magnetic field of the magnetic component (530''-b) (step b''-2). To magnetically orient at least a portion of the sheet-like magnetic or magnetizable pigment particles (step b'')), and wherein the second coating (520'') is at least partially cured with the second curing unit (550'') (step c'')), wherein the magnetic components (530''-a and 530''-b) are located on the first side of the substrate (i.e., the side containing the first coating (520') in the cured state).

[0040] Figure 5-2 shows the industrial two-step magnetic orientation step b) (b) is b') and / or b'')), wherein the coating (520) is first exposed to the magnetic field of the first magnetic component (530-a) and subsequently exposed to the magnetic field of the second magnetic component (530-b), the second magnetic component (530-b) being placed on a rotating magnetic cylinder, and wherein the coating (520) is at least partially cured with the curing unit (550) (step c)). Figure 5-3 illustrates the industrial two-step magnetic orientation step b)(b) is b') and / or b'')), wherein the coating (520) is first exposed to the magnetic field of the first magnetic component (530-a) and subsequently exposed to the combined magnetic field of the second magnetic component (530-b) and the third magnetic component (530-c), the second magnetic component (530-b) being mounted on a rotating magnetic cylinder and the third magnetic component (530-c) being located outside the rotating magnetic cylinder, and wherein the coating (520) is at least partially cured with a curing unit (550) (step c)).

[0041] FIG6 schematically illustrates a method for producing an optical effect layer (OEL) on a substrate (610) including a first set of steps (1) and a second set of steps (2) according to the invention, wherein both orientation steps b') and b'') comprise two magnetic orientation steps,

[0042] wherein the substrate (610) bearing a first coating (620') obtained by screen printing (640') (step a')) on its first side is first exposed to the magnetic field of a first magnetic component (630'-a) (step b'-1)), and then subsequently exposed to the combined magnetic field of a second magnetic component (630'-b) and a third magnetic component (630'-c) (step b'-2)).To achieve magnetic orientation of at least a portion of the sheet-like magnetic or magnetizable pigment particles as described on page 5 / 43 of the specification (step b'), and wherein at least a portion of the coating (620') is at least partially cured with a first curing unit (650') (step c'), wherein the magnetic component is located on a second side of the substrate (i.e., the side without the first coating (620')),

[0043] and wherein

[0044] after and consecutively thereafter in step c'), the second side is first supported by screen printing (640'') (step a) The substrate (610) of the second coating (620'') obtained is exposed to the magnetic field of the first magnetic component (630''-a) (step b''-1), and then subsequently exposed to the combined magnetic field of the second magnetic component (630''-b) and the third magnetic component (630''-c) (step b''-2), and wherein the second coating (620'') is at least partially cured with the second curing unit (650'') (step c''), wherein the magnetic component is located on the first side of the substrate (i.e., the side containing the first coating (620') in the cured state).

[0045] FIG7 schematically shows the magnetic component (730) used for biaxially oriented pigment particles and in the embodiments provided therein.

[0046] FIG8 schematically shows the magnetic component (830) used in and adapted to produce a pattern exhibiting dynamic movement of reflective strips in the embodiments E1-E2 provided therein, which split when the pattern is tilted.

[0047] FIG9 schematically illustrates a magnetic component (930) used in and adapted to produce a pattern exhibiting dynamic movement of a multi-ringed body that splits when the pattern is tilted, as provided in embodiments E3-E4.

[0048] The distances provided in the figures are illustrative only and not drawn to scale. Detailed Description

[0049] Definitions

[0050] The following definitions are used to clarify the meaning of terms defined in the discussion and claims of the specification.

[0051] As used herein, the indefinite article “a(a)” means one and greater than one, and does not necessarily limit its noun to the singular.

[0052] As used herein, the term “at least” is intended to define one or greater than one, for example, one, two, or three.

[0053] As used herein, the term “about” means that the quantity or value in discussion may be a specified particular value or some other value nearby. Generally, the term “about” indicating a value is intended to indicate a range within ±5% of that value. As an example, the phrase "about 100" indicates a range of 100 ± 5, that is, a range of 95 to 105. Generally, when the term "about" is used, similar results or effects according to the invention can be expected to be obtained within ± 5% of the indicated value.

[0054] As used herein,The term “and / or” means that all or only one of the elements of the group may be present. For example, “A and / or B” should mean “only A, or only B, or both A and B”. In the case of “only A”, the term also covers the possibility that B is not present, i.e., “only A, but not B”.

[0055] The term “comprising” as used herein is intended to be non-exclusive and open-ended. Thus, a coating composition, for example, comprising compound A, may comprise other compounds besides A. However, as in particular embodiments thereof, the term “comprising” also covers the more restrictive meanings of “consisting substantially of” and “consisting of”, such that, for example, “a dampening solution comprising A, B and optional C” may also consist (substantially) of A and B, or (substantially) of A, B and C.

[0056] As used herein, the term “optical effect layer (OEL)” refers to a coating or layer comprising oriented sheet-like magnetic or magnetizable pigment particles and a binder, wherein the sheet-like magnetic or magnetizable pigment particles are oriented by a magnetic field, and wherein the oriented sheet-like magnetic or magnetizable pigment particles are fixed / frozen in their orientation and position (i.e., after hardening / curing) to form a magnetically induced image. Specification 6 / 43 pages 9 CN 122422064 A

[0057] The term “coating composition” refers to any composition capable of forming an optical effect layer (OEL) on a solid substrate, and which may preferably, but not exclusively, be applied by a printing method. The coating composition comprises the sheet-like magnetic or magnetizable pigment particles described herein and the binder described herein.

[0058] As used herein, the term “wet” refers to a coating that has not yet cured, for example, a coating in which the sheet-like magnetic or magnetizable pigment particles are still capable of changing their position and orientation under the influence of external forces acting thereon.

[0059] As used herein, the term “marking” should refer to discontinuous layers, such as patterns, including but not limited to symbols, alphanumeric symbols, motifs, letters, words, numbers, signs, and drawings.

[0060] The term “curing” is used to refer to a method in which the viscosity of a coating composition in a first physical state that has not yet hardened (i.e., wet) is increased so as to transform it into a second physical state, i.e., a hardened or solid state, wherein the sheet-like magnetic or magnetizable pigment particles are fixed / frozen in their current position and orientation and cannot be moved or rotated again.

[0061] The term “secure document” refers to a document that is generally protected against forgery or tampering by at least one security feature. Examples of secure documents include, but are not limited to, documents of value and goods of value.

[0062] The term “security feature” is used to refer to an image, pattern, or graphic element that can be used for authentication purposes.

[0063] Where this specification refers to “preferred” embodiments / features, combinations of these “preferred” embodiments / features should also be considered disclosed.Provided that such a combination of “preferred” embodiments / features is technically meaningful.

[0064] The present invention provides a method for producing an optical effect layer (OEL) suitable as a security feature against counterfeiting or fraud, and comprising sheet-like magnetic or magnetizable pigment particles with magnetic orientation on a substrate. As shown in FIG1, the OEL comprises a first pattern in the form of a cured first coating 120' and a second pattern in the form of a cured second coating 120'', the first pattern comprising sheet-like magnetic or magnetizable pigment particles oriented according to a first magnetic pattern, the second pattern comprising sheet-like magnetic or magnetizable pigment particles oriented according to a second magnetic pattern, the first and second magnetic patterns being substantially symmetrical with respect to a mirror surface parallel to the substrate (x10), and wherein the first and second patterns are at least partially adjacent to each other (i.e., the second pattern is adjacent to at least a portion of the first pattern) and properly registered.

[0065] The phrase “the first and second magnetic patterns are substantially symmetrical with respect to a mirror surface parallel to the substrate (x10)” means that the field lines (F1) describing the magnetic field at the surface of the substrate (x10) in the region corresponding to the first pattern and the field lines (F2) describing the magnetic field at the surface of the substrate in the region corresponding to the second pattern are related to each other by symmetrical operations, regardless of their orientation. These symmetrical operations include mirror reflection on the substrate plane, and subsequently, optionally, one or more of the following operations: translation on the substrate plane, rotation relative to an axis perpendicular to the substrate, and mirror reflection on a plane perpendicular to the substrate. The term “field lines” means an imaginary line tangent to the magnetic field at any given point, and “regardless of their orientation” means considering only the orientation of the field lines in space, regardless of their orientation (NS or SN). While reflection on a horizontal plane does not change the shape of the magnetically induced pattern when viewed from a vertical viewing / illumination direction, it does change the apparent direction of the pattern's movement when the OEL is tilted. Therefore, when F1 and F2 are related by reflection on the substrate plane, the OEL exhibits a continuous effect when viewed from the vertical direction, and the effect appears to split when the OEL is tilted. When further symmetrical operations of translation / rotation / reflection are introduced, as described above, the OEL exhibits an effect with corresponding additional symmetry when viewed from the vertical direction, and the symmetry splits when the OEL is tilted.

[0066] As shown in FIG1, the first and second patterns in the form of cured first and second coatings x20'' and x20'' can independently contain a single sub-pattern, or can contain more than one sub-pattern as shown in FIG1, the more than one sub-pattern forming the first and second patterns independently respectively.

[0067] As stated herein,A first magnetic pattern of the first pattern and a second magnetic pattern of the second pattern are obtained by independently exposing the first radiation-curable coating composition of step a') and the second radiation-curable coating composition of step a'') to substantially the same magnetic field to form the first and second coatings (x20' and x20'', respectively) on page 7 / 43 of the specification, CN 122422064 A. The substantially the same magnetic field is preferably obtained by using the same magnetic components (the same x30' and x30'') during steps b') and b''). For example, the method for preparing the OEL of Example E1 provided therein uses the same magnetic components (x30), while applying magnetic fields on opposite sides of the substrate (x10) in orientation steps b') and b'' (see FIG. 5-1), resulting in two magnetic patterns that are substantially symmetrical with respect to a mirror surface parallel to the substrate (x10). Since the method described herein is a continuous method, wherein step a'') is performed directly after step c'), for an implementation using the "same magnetic component" during an industrial method using a rotating cylinder, this means that the first magnetic component (x30') is used during step b') and the second magnetic component (x30'') is used during step b''), wherein the components are two separate objects, rather than using "the" same object twice.

[0068] The method described herein comprises at least two sets of steps, namely a first set and at least a second set, the first set comprising steps a'), b'), and c'), and the second set comprising steps a''), b''), and c''). Therefore, the method described herein is a continuous method, which means that the second set of steps is performed directly after the first set, in other words, step a'') of the second set is performed after and directly after step c') of the first set, without removing the substrate carrying the first coating (x20') from the printing press, i.e., it is a continuous feed for the second set of steps. In other words, the multi-step method described herein is a sequential method using a single machine that allows for the application, preferably printing and coating, of a composition, exposure of the composition to a magnetic field, and at least partial curing of the composition. Examples of such a single machine allowing the multi-step process described herein are disclosed in US 2021 / 0316545, which comprises, in the following order: at least a first printing unit, a first alignment unit, a first curing unit, a second printing unit for downstream application of the composition, a second alignment unit, and a second curing unit. As mentioned therein, the method described herein allows for the preparation of an OEL comprising the first and second patterns described herein, the OEL exhibiting a continuous effect observable to the naked eye at a first viewing angle (e.g., obtained by using a mirror-symmetric magnetic field relative to a substrate (x10)), and the effect originating from the first and second magnetic patterns and comprising a continuous image extending from the first pattern to the second pattern.The effect described herein splits when tilted and recombines when tilted back to the first viewpoint to form the same continuous image; this highly dynamic effect is due not only to the perfect registration of the applied first and second graphics, but also to the perfect registration derived from the first and second magnetic patterns.

[0069] In the first viewpoint, the observer perceives the OEL as a continuous image extending from one graphic to another as described herein, wherein the continuous image may or may not be centered within the OEL, i.e., may or may not be centered within the combination of the first and second graphics described herein.

[0070] If the first and / or second graphics described herein independently contain a first sub-graphic and a second sub-graphic (as shown, for example, in FIG. 1), the continuous effect / image is obtained from a combination of multiple or all sub-graphics.

[0071] FIG. 1 schematically illustrates the first and second magnetic patterns of the OEL produced by the method described herein, wherein the OEL exhibits a single bar in a first viewpoint and exhibits two bars moving in opposite directions when the OEL is tilted; wherein the effect is based on pigment particle orientation independently mimicking the curved surface across the coating. An OEL exhibiting two bars moving in opposite directions when tilted comprises the first and second patterns described herein (in the form of a cured first coating 120' and a cured second coating 120'' on a substrate 110). Thanks to the symmetry of the first and second magnetic patterns relative to a mirror surface parallel to the substrate (110), an observer sees one bright bar moving in one direction when tilted and the other bright bar moving in the opposite direction when tilted, from a different perspective than that from which the two bars are viewed as a single bar. In other words, the observer sees one bright bar moving away from the observer when the OEL is tilted, and the other bright bar moving towards the observer when the OEL is tilted. The observation of the bars moving away from or towards the observer when the OEL is tilted originates from the specific magnetic orientation pattern of the pigment particles. Figure 1 shows two patterns: for pattern 120', Figure 1 shows a magnetic orientation pattern containing particles oriented in a concave manner and following a positively curved surface; and for pattern 120'', Figure 1 shows a magnetic orientation pattern containing particles oriented in a convex manner and following a negatively curved surface, according to specification page 8 / 43, 11 CN 122422064 A. The terms "convex manner" or "convex curvature" and "concave manner" or "concave curvature" refer to the apparent curvature of the curved surface as seen by an observer (Figure 1) when viewing the OEL from one side of the substrate (110) bearing the first coating (120') (as shown by the eye in Figure 1). The curvature of the curved surface follows the magnetic field lines generated by the magnetic field generating device at the location where the OEL is generated. "Convex curvature" refers to negatively curved magnetic field lines (as shown in Figure 1, pattern 120''); "concave curvature" refers to positively curved magnetic field lines (as shown in Figure 1, pattern 120'). When the OEL is tilted backward,The convex curvature results in a visual effect characterized by the bright bars moving downwards, and the concave curvature (positive bending orientation) results in a visual effect characterized by the bright bars moving upwards when the OEL is tilted backwards.

[0072] The OEL described herein comprises first and second patterns (i.e., first cured coating 120' and second cured coating 120'') on opposite sides of a substrate (110), wherein the substrate (110) is preferably transparent, and wherein the first and second patterns are at least partially adjacent to each other (i.e., the second pattern is adjacent to at least a portion of the first pattern) and properly registered such that, from a first perspective, an observer perceives the OEL as a continuous feature in either perspective or transparency viewing mode. By "adjacent," this means that the projections of the first and second patterns (first coating (x20') and second coating (x20'')) onto each side of the substrate (110) (see the dashed lines in FIG. 1) are continuous (i.e., they share at least one area together and have a common boundary). The projections of the first and second patterns on each side of the substrate (110) are at least partially adjacent (i.e., the second pattern is adjacent to at least a portion of the first pattern) and properly registered, preferably at least partially juxtaposed and properly registered or at least partially staggered and properly registered. The first and second patterns may be continuous or discontinuous.

[0073] The method described herein includes at least two independent steps a') and a''), which include: applying a first radiation-curable coating composition to a first side of the substrate (x10) to form a first coating (x20') (step a'), and including: applying a second radiation-curable coating composition to a second side of the substrate (x10) (i.e., the side of the substrate (x10) that does not contain the first coating (x20')) to form a second coating (x20'') (step a'')), wherein the first and second radiation-curable coating compositions are in a first physical state, which allows them to be applied as layers and they are in a pre-cured (i.e., wet) state, wherein sheet-like magnetic or magnetizable pigment particles can move and rotate within the binder material. The method described herein comprises at least two independent steps b') and b''), which include: independently exposing the first and second radiation-curable coating compositions of steps a') and a'') to a magnetic field to magnetically orient at least a portion of the sheet-like magnetic or magnetizable pigment particles, and forming first and second coatings (and forming first and second patterns), the first and second patterns thus obtained having registered specific magnetic orientation patterns, i.e., the method described herein allows control of the position of the magnetic components (x30' and x30'') during steps b') and b''), such that the effect / image of the OEL described herein, observed from a first viewpoint, is an image continuously extending from the first pattern to the second pattern.Therefore, the image described therein splits when tilted and recombines when tilted back to the first viewing angle to form the same effect, thereby allowing easy authentication due to the continuity of the effect in one viewing angle, which is caused not only by the perfect registration of the applied first and second patterns, but also by the perfect registration of the effect derived from the first and second magnetic patterns.

[0074] As mentioned therein, the first and second coatings (x20' and x20'') (and the respective first and second patterns) are at least partially adjacent to each other (i.e., the second pattern is adjacent to at least a portion of the first pattern) and properly registered, which means that not only is the radiation-curable coating composition applied with no or very limited (less than 1 mm, preferably less than 0.5 mm, more preferably less than or equal to 0.2 mm) misalignment and misalignment between the second coating (x20'') and the first coating (x20'), but the first and second magnetic patterns provided by the OEL obtained in one first viewing angle appear to the naked eye as a continuous layer (i.e., an unbroken image). The registration is allowed by the claimed continuous method. According to one embodiment, the first and second coatings (x20' and x20'') are registered within ±1 mm, preferably ±0.5 mm, more preferably ±0.2 mm. This registration is permitted using a single machine via a claimed continuous method, as described on page 9 / 43 of the specification, CN 122422064 A.

[0075] Preferably, steps a') and a'') are performed independently by a printing method, preferably independently selected from the group consisting of screen printing, rotary gravure printing, flexographic printing, and gravure printing (also known in the art as engraved copperplate printing and engraved steel mold printing), more preferably from the group consisting of screen printing, rotary gravure printing, and flexographic printing, and even more preferably by screen printing.

[0076] Screen printing (also known in the art as silkscreen printing) is a stencil method in which ink is transferred through a stencil to a surface supported by a finely woven mesh of silk, such as monofilaments or multifilaments or metal wires made of synthetic fibers like polyamide or polyester, stretched on a frame made of, for example, wood or metal (e.g., aluminum or stainless steel). Alternatively, the screen printing mesh can be a chemically etched, laser-etched, or electrically formed porous metal foil, such as stainless steel foil. The pores of the mesh are blocked in non-image areas and remain open in image areas; the image carrier is called the screen. Screen printing can be planar or rotary. Screen printing is illustrated, for example, in *The Printing Ink Manual*, RH Leach and RJ Pierce, Springer, 5th edition.Further description is provided on pages 58-62 and in Printing Technology, J.M. Adams and PA Dolin, Delmar Thomson Learning, 5th edition, pp. 293-328.

[0077] Rotary gravure (also known in the art as gravure) is a printing method in which image elements are engraved in the surface of a cylinder. Non-image areas are at a constant, unpainted level. Before printing, the entire printing plate (both non-printing and printed elements) is inked and filled with ink. Before printing, the ink is removed from the non-image areas by a wiper or doctor blade, leaving only the ink in the cells. The image is transferred from the cells to the substrate by pressure typically in the range of 2-4 bar and by the adhesive force between the substrate and the ink. The term rotary gravure does not include, for example, intaglio printing methods that rely on different kinds of ink (also known in the art as engraving steel molds or copperplate printing methods). Further details are provided in "Handbook of Print Media," Helmut Kipphan, Springer, p. 48 and "The Printing Ink Manual," RH Leach and RJ Pierce, Springer, 5th edition, pp. 42-51.

[0078] Flexographic printing preferably uses a unit having a doctor blade, preferably a cavity doctor blade, an anilox roller, and a plate cylinder. The anilox roller advantageously has small cells whose volume and / or density determine the ink application rate. The doctor blade is placed against the anilox roller and simultaneously scrapes off excess ink. The anilox roller transfers the ink to the plate cylinder, which ultimately transfers the ink to the substrate. Specific designs can be achieved using designed photopolymer plates. The plate cylinder can be made of polymer or elastomeric materials. Polymers are primarily used as photopolymers in printing plates and sometimes as seamless coatings on sleeves. Photopolymer printing plates are made of photosensitive polymers that are cured by ultraviolet (UV) light. The photopolymer printing plate is cut to the required size and placed in a UV light exposure unit. One side of the plate is fully exposed to UV light to harden or cure the base of the plate. The plate is then flipped over, the film for the job is mounted on the uncured side, and the plate is further exposed to UV light. This hardens the plate in the image area. The plate is then processed to remove the uncured photopolymer from the non-image areas, which lowers the plate surface in these non-image areas. After processing, the plate is dried and given a post-exposure dose of UV light to cure the entire plate. Preparation of plate cylinders for flexographic printing is discussed in Printing Technology, J.M. Adams and P.A. Dolin.Described in Delmar Thomson Learning, 5th Edition, pp. 359-360 and The Printing Ink Manual, RH Leach and RJ Pierce, Springer, 5th Edition, pp. 33-42.

[0079] The first and second radiation-curable coating compositions are applied independently during steps a') and a'') to form a first coating (x20') and a second coating (x20''), respectively. The first and second radiation-curable coating compositions independently contain a binder and sheet-like magnetic or magnetizable pigment particles as described herein. As shown in Figures 1, 3, 5, and 6, during step a'), a first radiation-curable coating composition (page 10 / 43 of specification, 13 CN 122422064 A) is applied to a first side of the substrate (x10) to form a first coating (x20'), and during step a''), a second radiation-curable coating composition is applied to a second side of the substrate (i.e., the side of the substrate without the first coating (x20')) to form a second coating (x20'').

[0080] According to one embodiment, the first radiation-curable coating composition exhibits a color, and the second radiation-curable coating composition exhibits the same color visible to the naked eye. According to one embodiment, the first and second radiation-curable coating compositions have different binders but contain the same flake-like magnetic or magnetizable pigment particles, such that they exhibit the same color visible to the naked eye. According to another embodiment, the first and second radiation-curable coating compositions are identical, i.e., they contain the same binder and contain the same flake-like magnetic or magnetizable pigment particles.

[0081] According to one embodiment, a first radiation-curable coating composition exhibits a first color, and a second radiation-curable coating composition exhibits a second color, the second color being different from the first color to the naked eye. OELs containing first and second patterns of different colors exhibit a striking effect not only due to their dynamic effect (a continuous effect observed at a first viewing angle, wherein the effect splits when tilted and recombines to form the same effect when tilted back to the first viewing angle), but also due to the combination of complex adjacent patterns of different colors, resulting in a high level of anti-counterfeiting.

[0082] According to one embodiment, the first and second radiation-curable coating compositions contain the same sheet-like magnetic or magnetizable pigment particles, but contain different binders, the binder of the first composition containing dyes and / or colorants, such that the compositions exhibit different colors to the naked eye. According to one embodiment, the first and second radiation-curable coating compositions contain the same sheet-like magnetic or magnetizable pigment particles, but contain different binders, the binder of the second composition containing dyes and / or colorants.This results in the compositions exhibiting different colors visible to the naked eye. According to one embodiment, the first and second radiation-curable coating compositions contain the same flake-like magnetic or magnetizable pigment particles, but contain different binders. The binder of the first composition contains dyes and / or colorants, and the binder of the second composition contains dyes and / or colorants of different colors, resulting in the compositions exhibiting different colors visible to the naked eye. For optically variable flake-like magnetic or magnetizable pigment particles, i.e., pigments that exhibit different colors when tilted (i.e., exhibiting a face color and different angular colors), "different colors" refers to different face colors or different angular colors or different face colors and angular colors. According to one embodiment, the first radiation-curable coating composition contains optically variable flake-like magnetic or magnetizable pigment particles having a first face color and a first angular color, and the second radiation-curable coating composition contains optically variable flake-like magnetic or magnetizable pigment particles having a second face color and a second angular color, wherein the first face color is different from the second face color, and the first angular color is different from the second angular color. According to one embodiment, a first radiation-curable coating composition comprises optically variable flaky magnetic or magnetizable pigment particles having a first face color and a first angular color, and a second radiation-curable coating composition comprises optically variable flaky magnetic or magnetizable pigment particles having a second face color and a second angular color, wherein the first face color is the same as the second face color, and the first angular color is different from the second angular color. According to one embodiment, a first radiation-curable coating composition comprises optically variable flaky magnetic or magnetizable pigment particles having a first face color and a first angular color, and a second radiation-curable coating composition comprises optically variable flaky magnetic or magnetizable pigment particles having a second face color and a second angular color, wherein the first face color is different from the second face color, and the first angular color is the same as the second angular color.

[0083] The first and second coating compositions described herein, as well as the first coating layer (x20') and the second coating layer (x20'') described herein, comprise the flaky magnetic or magnetizable pigment particles described herein. In contrast to needle-like pigment particles, which can be considered quasi-one-dimensional particles, flaky pigment particles are quasi-two-dimensional particles because of their large aspect ratio. As shown in Figure 2, plate-like pigment particles can be considered as two-dimensional structures, where dimensions X and Y are substantially larger than dimension Z. Plate-like pigment particles are also referred to in the art as oblate particles or flakes. Such pigment particles can be described as having a principal axis X corresponding to their longest dimension passing through the pigment particle, and a second axis Y perpendicular to X and corresponding to the second longest dimension passing through the pigment particle. In other words, the XY plane roughly defines the plane formed by the first and second longest dimensions of the pigment particle.The Z-dimension is ignored.

[0084] The sheet-like magnetic or magnetizable pigment particles described herein have an isotropic reflectivity relative to incident electromagnetic radiation due to their non-spherical shape, for which the hardened / cured binder material is at least partially transparent. As used herein, the term "anisotropic reflectivity" means that the proportion of radiation incident from a first angle that is reflected by the particles to a certain (viewing) direction (second angle) is a function of the particle orientation, i.e., a change in particle orientation relative to the first angle can result in different magnitudes of reflection to the viewing direction.

[0085] In the first and second patterns of the OEL described herein, the sheet-like magnetic or magnetizable pigment particles described herein are dispersed in the first and second coatings (x20' and x20''), respectively, which contain a hardened binder material that fixes the orientation of the sheet-like magnetic or magnetizable pigment particles. The binder material, at least in its hardened or solid state (also referred to herein as a second state), is at least partially transparent to electromagnetic radiation in the wavelength range between 200 nm and 2500 nm, i.e., in the wavelength range commonly referred to as the “spectrum” and including the infrared, visible, and UV portions of the electromagnetic spectrum. Therefore, particles contained in the binder material in its hardened or solid state, and their orientation-dependent reflectivity, can be perceived at some wavelengths within this range. Preferably, the hardened binder material is at least partially transparent to electromagnetic radiation in the wavelength range between 200 nm and 800 nm, more preferably between 400 nm and 700 nm. Hereinafter, the term “transparent” means that, at the relevant wavelength, electromagnetic radiation has a transmittance of at least 50%, more preferably at least 60%, and even more preferably at least 70% through a 20 μm layer of the hardened binder material present in the OEL (excluding flake-like magnetic or magnetizable pigment particles, but all other optional components of the OEL in their presence). This can be determined, for example, by measuring the transmittance of a test piece of hardened binder material (excluding sheet-like magnetic or magnetizable pigment particles) according to well-established test methods, such as DIN 5036-3 (1979-11).

[0086] Sheet-like magnetic or magnetizable pigment particles, as described herein, are defined as having an isotropic reflectivity relative to incident electromagnetic radiation due to their non-spherical shape, for which the cured binder material is at least partially transparent. As used herein, the term "anisotropic reflectivity" means that the proportion of radiation incident from a first angle that is reflected by the particles to a certain (viewing) direction (second angle) is a function of particle orientation, i.e., a change in particle orientation relative to the first angle can result in different magnitudes of reflection to the viewing direction. Preferably,The flake-like magnetic or magnetizable pigment particles described herein have anisotropic reflectivity relative to incident electromagnetic radiation in some portions or over the entire wavelength range of about 200 nm to about 2500 nm, more preferably about 400 nm to about 700 nm, such that a change in particle orientation results in a change in the direction of reflection from the particle. As is known to those skilled in the art, the magnetic or magnetizable pigment particles described herein differ from conventional pigments because conventional pigment particles exhibit the same color and reflectivity regardless of particle orientation, while the magnetic or magnetizable pigment particles described herein exhibit reflectivity or color, or both, depending on particle orientation.

[0087] The first and second radiation-curable coating compositions and the first and second coatings (x20', x20'') described herein independently contain the flake-like magnetic or magnetizable pigment particles described herein, preferably in an amount of about 1 wt.% to about 40 wt.%, preferably between about 3 wt.% and about 35 wt.%, more preferably between about 5 wt.% and about 30 wt.%, the weight percentages being based on the total weight of the radiation-curable coating composition or coating.

[0088] Suitable examples of the sheet-like magnetic or magnetizable pigment particles described herein include, but are not limited to, pigment particles comprising: magnetic metals selected from the group consisting of cobalt (Co), iron (Fe), and nickel (Ni); magnetic alloys of iron, manganese, cobalt, nickel, or mixtures thereof; magnetic oxides of chromium, manganese, cobalt, iron, nickel, or mixtures thereof; or mixtures thereof. The term "magnetic" with respect to metals, alloys, and oxides refers to ferromagnetic or ferrimagnetic metals, alloys, and oxides. Magnetic oxides of chromium, manganese, cobalt, iron, nickel, or mixtures thereof can be pure oxides or mixed oxides. Examples of magnetic oxides include, but are not limited to, iron oxides such as hematite (Fe2O3), magnetite (Fe3O4), chromium dioxide (CrO2), magnetic ferrite (MFe2O4), magnetic spinel (MR2O4), magnetic hexagonal ferrite (MFe12O19), magnetic positive ferrite (RFeO3), and magnetic garnet M3R2(AO4)3, where M represents a divalent metal, R represents a trivalent metal, and A represents a tetravalent metal.

[0089] Examples of the sheet-like magnetic or magnetizable pigment particles described herein include, but are not limited to, pigment particles containing a magnetic layer M, said magnetic layer M being made of one or more magnetic metals such as cobalt (Co), iron (Fe), or nickel (Ni) and magnetic alloys of iron, cobalt, or nickel, wherein said magnetic or magnetizable pigment particles may be a multilayer structure containing one or more additional layers. Preferably,One or more additional layers are layers A, independently made of one or more of the group consisting of metal fluorides such as magnesium fluoride (MgF2), silicon oxide (SiO), silicon dioxide (SiO2), titanium oxide (TiO2), and aluminum oxide (Al2O3), more preferably silicon dioxide (SiO2); or layers B, independently made of one or more of the group consisting of metals and metal alloys, preferably consisting of reflective metals and reflective metal alloys, more preferably consisting of one or more of the group consisting of silver (Ag), aluminum (Al), chromium (Cr), and nickel (Ni), and even more preferably aluminum (Al); or combinations of one or more of the layers A as described above and one or more of the layers B as described above. Typical examples of the above-mentioned multilayered sheet-like magnetic or magnetizable pigment particles 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, M / A / M multilayer structure, B / A / M / A multilayer structure, B / A / M / B multilayer structure, B / A / M / B / A multilayer structure, B / A / M / A / B multilayer structure, B / A / M / A / B multilayer structure, B / A / B / A / M / A / B / A / B multilayer structure, and A / B / A / B / A / M / A / B / A / B / A multilayer structure, wherein layer A, magnetic layer M, and layer B are selected from those mentioned above.

[0090] The UV-Vis radiation-curable coating compositions described herein may comprise sheet-like optically variable magnetic or magnetizable pigment particles, and / or sheet-like magnetic or magnetizable pigment particles without optically variable properties. Preferably, at least a portion of the sheet-like magnetic or magnetizable pigment particles described herein constitutes sheet-like optically variable magnetic or magnetizable pigment particles. In addition to the explicit security provided by the color-changing properties of the optically variable magnetic or magnetizable pigment particles, which allows for easy detection, identification, and / or differentiation using unassisted human senses of articles or security documents carrying inks, coating compositions, or coatings containing the optically variable magnetic or magnetizable pigment particles described herein from their potential for counterfeiting, the optical properties of the optically variable magnetic or magnetizable pigment particles can also be used as a machine-readable tool for identifying OELs. Therefore, the optical properties of the optically variable magnetic or magnetizable pigment particles can simultaneously serve as implicit or semi-implicit security features in authentication processes that analyze the optical (e.g., spectral) properties of the pigment particles, thereby enhancing anti-counterfeiting capabilities.

[0091] The use of flake-shaped optically variable magnetic or magnetizable pigment particles in the coating used to produce OEL enhances the importance of OEL as a security feature in secure document applications, because this material is reserved for the secure document printing industry and is not commercially available to the public.

[0092] As described above,Preferably, at least a portion of the sheet-like magnetic or magnetizable pigment particles are composed of sheet-like optically variable magnetic or magnetizable pigment particles. These are more preferably selected from the group consisting of sheet-like magnetic thin-film interference pigment particles and sheet-like interference coated pigment particles.

[0093] Magnetic thin-film interference pigment particles are known to those skilled in the art and are disclosed, for example, in US 4,838,648; WO 2002 / 073250 A2; EP 0 686 675 B1; WO 2003 / 000801 A2; US 6,838,166; WO 2007 / 131833 A1; EP 2 402 401 B1; WO 2019 / 103937 A1; EP 3 587 500 A1; EP 3 587 501 A1; EP 3 587 502 A1; EP 3 587503 A1; WO 2020 / 006286 A1; WO 2020 / 131700 A1; US ​​2021 / 0101402; US 2021 / 038812; US 2022 / 0282094 and the references therein. Preferably, the magnetic thin film interference pigment particles comprise pigment particles having a five-layer Fabry-Perot multilayer structure and / or pigment particles having a six-layer Fabry-Perot multilayer structure and / or pigment particles having a seven-layer Fabry-Perot multilayer structure and / or pigment particles having a nine-layer Fabry-Perot multilayer structure and / or pigment particles having an eleven-layer Fabry-Perot multilayer structure and / or pigment particles having a multilayer structure combining one or more multilayer Fabry-Perot structures.

[0094] The preferred five-layer Fabry-Perot multilayer structure is composed of an absorber / dielectric / reflector / dielectric / absorber multilayer structure, wherein the reflector and / or absorber are also magnetic layers. Preferably, the reflector and / or absorber are magnetic alloys containing nickel, iron and / or cobalt, and / or containing nickel, iron and / or cobalt.And / or a magnetic layer comprising a magnetic oxide of nickel (Ni), iron (Fe), and / or cobalt (Co).

[0095] A further preferred five-layer Fabry-Perot multilayer structure is composed of a dielectric / reflector / magnetic material / reflector / dielectric multilayer structure.

[0096] A preferred six-layer Fabry-Perot multilayer structure is composed of an absorber / dielectric / reflector / magnetic material / dielectric / absorber multilayer structure.

[0097] A preferred seven-layer Fabry-Perot multilayer structure is composed of an absorber / dielectric / reflector / magnetic material / reflector / dielectric / absorber multilayer structure as disclosed in US 4,838,648.

[0098] A preferred nine-layer Fabry-Perot multilayer structure is composed of a dielectric / absorber / dielectric / reflector / magnetic material / dielectric / absorber / dielectric multilayer structure.

[0099] The preferred eleven-layer Fabry-Perot multilayer structure is composed of an absorber / dielectric / absorber / dielectric / reflector / magnetic body / reflector / dielectric / absorber / dielectric / absorber multilayer structure.

[0100] Preferably, the reflector layer described herein is independently made of: selected from the group consisting of metals and metal alloys, preferably selected from the group consisting of reflective metals and reflective metal alloys, more preferably selected from the group consisting of aluminum (Al), silver (Ag), copper (Cu), gold (Au), platinum (Pt), tin (Sn), titanium (Ti), palladium (Pd), rhodium (Rh), niobium (Nb), chromium (Cr), nickel (Ni) and their alloys, even more preferably selected from one or more of the group consisting of aluminum (Al), chromium (Cr), nickel (Ni) and their alloys, and even more preferably aluminum (Al). Preferably, the dielectric layer is independently made of: a metal fluoride selected from the group consisting of magnesium fluoride (MgF2), aluminum fluoride (AlF3), cerium fluoride (CeF3), lanthanum fluoride (LaF3), sodium aluminum fluoride (e.g., Na3AlF6), neodymium fluoride (NdF3), samarium fluoride (SmF3), barium fluoride (BaF2), calcium fluoride (CaF2), lithium fluoride (LiF), and metal oxides such as silicon oxide (SiO), silicon dioxide (SiO2), titanium oxide (TiO2), and aluminum oxide (Al2O3); more preferably, one or more selected from the group consisting of magnesium fluoride (MgF2) and silicon dioxide (SiO2); and even more preferably, magnesium fluoride (MgF2). Preferably,The absorber layer is independently made of one or more of the following: aluminum (Al), silver (Ag), copper (Cu), palladium (Pd), platinum (Pt), titanium (Ti), vanadium (V), iron (Fe), tin (Sn), tungsten (W), molybdenum (Mo), rhodium (Rh), niobium (Nb), chromium (Cr), nickel (Ni), their metal oxides, their metal sulfides, their metal carbides, and their metal alloys; more preferably, chromium (Cr), nickel (Ni), their metal oxides, and their metal alloys; and even more preferably, chromium (Cr), nickel (Ni), and their metal alloys. Preferably, the magnetic layer comprises nickel (Ni), iron (Fe), and / or cobalt (Co); and / or a magnetic alloy comprising nickel (Ni), iron (Fe), and / or cobalt (Co); and / or a magnetic oxide comprising nickel (Ni), iron (Fe), and / or cobalt (Co). When magnetic thin-film interference pigment particles containing a seven-layer Fabry-Perot structure are preferred, it is particularly preferred that the magnetic thin-film interference pigment particles contain a seven-layer Fabry-Perot absorber / dielectric / reflector / magnetic body / reflector / dielectric / absorber multilayer structure composed of Cr / MgF2 / Al / M / Al / MgF2 / Cr multilayer structure, wherein M is Ni, Fe or Co.

[0101] The magnetic thin-film interference pigment particles described herein can be multilayer pigment particles considered safe for human health and the environment, and are based on, for example, five-layer Fabry-Perot multilayer structures, six-layer Fabry-Perot multilayer structures, seven-layer Fabry-Perot multilayer structures, nine-layer Fabry-Perot multilayer structures, eleven-layer Fabry-Perot multilayer structures, and multilayer structures having combinations of one or more multilayer Fabry-Perot structures. The pigment particles described in this specification (page 14 / 43, CN 122422064 A) comprise one or more magnetic layers containing a magnetic alloy having a substantially nickel-free composition comprising about 40 wt.% to about 90 wt.% iron, about 10 wt.% to about 50 wt.% chromium, and about 0 wt.% to about 30 wt.% aluminum. Typical examples of multilayer pigment particles considered safe for human health and the environment can be found in EP 2 402 401 B1, the contents of which are incorporated herein by reference in their entirety.

[0102] Suitable interference-coated pigment particles comprising one or more magnetic materials include, but are not limited to, structures consisting of a substrate selected from the group consisting of a core coated with one or more layers, wherein the core or at least one of the layers is magnetic. For example, suitable interference-coated pigment particles comprise a core made of the magnetic materials described above, the core being coated with one or more layers made of one or more metal oxides.Alternatively, they may have a structure consisting of a core made of synthetic or natural mica, layered silicates (e.g., talc, kaolin, and sericite), glass (e.g., borosilicate), silica (SiO2), alumina (Al2O3), titanium dioxide (TiO2), graphite, and mixtures thereof, the core being coated with one or more magnetic materials. Furthermore, one or more additional layers, such as a coloring layer, may be present.

[0103] The flake-like magnetic or magnetizable pigment particles of the first and second coatings described herein preferably have a size d50 (measured by direct optical particle size analyzer) between about 2 μm and about 50 μm.

[0104] The flake-like magnetic or magnetizable pigment particles described herein may be surface-treated to protect them from any degradation that may occur in the coating composition and coating and / or to promote their incorporation into the coating composition and coating; corrosion-inhibiting materials and / or wetting agents may typically be used.

[0105] Furthermore, after independently applying the first and second radiation-curable coating compositions described herein to form the first coating (x20') and the second coating (x20'') (steps a') and a''), the first and second radiation-curable coating compositions of steps a') and a'') are independently exposed to the magnetic field of the magnetic components (x30', x30'', respectively) to independently magnetically orient at least a portion of the sheet-like magnetic or magnetizable pigment particles (steps b') and b'', respectively).

[0106] The method described herein includes at least two independent steps b') and b''), which include exposing the first and second radiation-curable coating compositions described herein to the magnetic field of the magnetic component (x30') or the magnetic component (x30''), respectively, to magnetically orient at least a portion of the sheet-like magnetic or magnetizable pigment particles. The magnetic component (x30') used in step b') and the magnetic component (x30'') used in step b'') are the same component, such that, for example, when used during an industrial process using a rotating cylinder, they are two identical separate objects, i.e., such that the first and second magnetic patterns are magnetic orientation patterns that are mirror-symmetrical.

[0107] During the magnetic orientation steps b') and b'') described herein, the substrate (x10) may be independently configured on a non-magnetic support plate (x70) made of one or more non-magnetic materials.

[0108] As described below, "x30'" and "x30''" independently refer to a single magnet, or an assembly (x30) containing two or more magnets, or an assembly containing one or more magnets and an engraved magnetic plate, or an assembly containing one or more magnets and a soft magnetic plate, or an assembly containing a magnet and one or more pole pieces or containing two or more magnets and one or more pole pieces.The magnetic components (x30' and x30'') are selected based on the design of the magnetic orientation patterns of the first and second graphics of the OEL to be generated. If the magnetic components (x30' and x30'') contain more than one component, the sheet-like magnetic or magnetizable pigment particles are exposed to the combined magnetic field of the more than one component.

[0109] According to one embodiment, the method described herein includes a magnetic alignment step b') and a magnetic alignment step b''), both of which include a magnetic alignment step, wherein a substrate (x10) bearing a first coating (x20') on its first side is exposed to the magnetic field of a magnetic component (x30'), and wherein a substrate (x10) bearing a second coating (x20'') on its second side is exposed to the magnetic field of a magnetic component (x30''), and wherein the two magnetic components (x30' and x30'') are the same components, in particular two identical separate objects, to produce first and second magnetic patterns that are mirror-symmetrical with respect to the substrate (x10).

[0110] According to one embodiment, the method described herein includes a magnetic alignment step b') and a magnetic alignment step b''), both of which include a magnetic alignment step, wherein a substrate (x10) carrying a first coating (x20') on its first side is exposed to a magnetic field of a magnetic component (x30') located on the first side of the substrate (i.e., the side containing the first coating (x20') in a wet state), and wherein a substrate (x10) carrying a second coating (x20'') on its second side is exposed to a magnetic component (x30'') located on the second side of the substrate (i.e., without the first coating (x20') and containing the second coating (x20'') in a wet state), and wherein the two magnetic components (x30' and x30'') are the same components, in particular two identical separate objects, to produce first and second magnetic patterns that are mirror-symmetrical with respect to the substrate (x10).

[0111] According to one embodiment and as shown in FIG3 (not drawn to scale), the method herein includes a first set of steps (1) and a second set of steps (2), wherein the magnetic orientation step b') of the first set of steps (1) and the magnetic orientation step b'') of the second set of steps (2) are both independently a magnetic orientation step, wherein a substrate (310) carrying a first coating (320') on its first side is exposed to a magnetic field of a magnetic component (330') located on a second side of the substrate (i.e., the side without the first coating (320'), and wherein a substrate (310) carrying a second coating (320'') on its second side is exposed to a magnetic field of a magnetic component (330'') located on a first side of the substrate (i.e., the side containing the first coating (320') in a cured state.And two of the magnetic components (330' and 330'') are identical components, specifically two identical individual objects, to produce first and second magnetic patterns that are mirror-symmetrical relative to the substrate (310).

[0112] Figure 4A-1 (not drawn to scale) illustrates a method in which orientation step b) (b') and / or b'')) includes a magnetic orientation step in which the radiation-curable coating composition described herein is exposed to the magnetic field of a single magnetic component (430), wherein the magnetic component (430) is mounted on a rotating magnetic cylinder. Figure 4A-2 (not drawn to scale) illustrates a method in which orientation step b) (b') and / or b'')) includes a magnetic orientation step in which the radiation-curable coating composition described herein is exposed to the magnetic field of a single magnetic component (430), wherein the magnetic component (430) is arranged in the vicinity of a rotating cylinder.

[0113] As described herein, the method allows the preparation of an OEL in which the first and second patterns, when combined in a first viewpoint, exhibit a continuous effect / image, the effect being derived from first and second magnetic orientation patterns, and the effect comprising an image continuously extending from the first pattern to the second pattern (see Example E1, where the effect resulting from a particular combination of the first and second patterns is contained in a single strip in a first viewpoint, wherein when the OEL is tilted, i.e., in a viewpoint different from the first viewpoint, the strip splits into two strips moving in opposite directions, and see Example E3, where the effect resulting from a particular combination of the first and second patterns is contained in a multi-ring in a first viewpoint, wherein when the OEL is tilted, the multi-ring splits into multiple circular segments).

[0114] According to one embodiment, the method described herein allows for the preparation of an OEL, wherein a combination of a first graphic and a second graphic exhibits dynamic movement when the OEL is tilted and displays more than one mark, wherein steps b') and b'') independently comprise exposing a radiation-curable coating composition to a magnetic assembly (x30) comprising a rod-shaped dipole magnet and an engraved magnetic plate, wherein the engraved magnetic plate comprises more than one engraving having more than one mark shape, wherein the engraved magnetic plate is positioned above the rod-shaped dipole magnet. The engraved magnetic plate described herein is preferably made of a permanent magnet powder material and a polymer. The engraved magnetic plate (x30) described herein can generally be produced by injection molding or by metal or laser engraving. Preferred permanent magnet powder materials include cobalt, iron and their alloys, chromium dioxide, general-purpose magnetic oxide spinel, general-purpose magnetic garnet, including general-purpose magnetic ferrites such as calcium, strontium, and barium hexagonal ferrites (CaFe12O19, SrFe12O19, BaFe12O19), general-purpose AlNiCo alloys, general-purpose samarium-cobalt (SmCo) alloys, and general-purpose rare earth-iron-boron alloys (such as NdFeB).And their permanent magnet chemical derivatives (as indicated by common terminology) and mixtures thereof. Plates made from composite materials containing polymers and permanent magnet powders can be obtained from many different sources, such as Bomatec, Höri, CH, ARNOLD® Magnetic Technologies (Plastiform®) or Materiali Magnetici, Albarate, Milano, IT (Plastoferrite).

[0115] According to one embodiment, the method described herein includes both steps b') and b''), which include exposing the radiation-curable coating composition to magnetic components disclosed in US 8,025,952, EP 1 819 525 B1, and WO 2022 / 049024 A1, wherein the effect is the so-called "Venetian-blind" effect. Figures 5A-B of US 7,047,883 disclose a magnetic component comprising two spaced magnets 84 placed on a magnetic substrate 62, their north poles facing the substrate. Figure 9B of US 7,047,883 discloses a magnetic component comprising magnets 140, and the substrate comprising a coating positioned offset relative to the magnetic axis. Figure 9C of US 7,047,883 discloses a magnetic assembly comprising two magnets 142 and one magnet 142' having a rhomboid cross-section, wherein the north poles of the two magnets 142 face the substrate, and the south pole of the middle magnet 142' faces the substrate. Figure 9D of US 7,047,883 discloses a magnetic assembly comprising two magnets 144 and one magnet 144' having a roof-shaped, hexagonal, circular, trapezoidal, or other cross-section, wherein the north poles of the two magnets 144 face the substrate, and the south pole of the middle magnet 144' faces the substrate. Figure 9E of US 7,047,883 discloses a magnetic assembly comprising five magnets, wherein the first magnet 142 is a rhomboid magnet with its north pole facing the substrate. The second magnet 146 is a rectangular magnet with its south pole facing the substrate; the third magnet 148 is a magnet with a rounded top and its north pole facing the substrate; the fourth magnet 150 is roof-shaped with its south pole facing the substrate; and the fifth magnet 152 is also a roof-shaped magnet with its north pole facing the substrate. Figure 4A1 of WO 2022 / 049024 A1 discloses a magnetic assembly comprising rod-shaped dipole magnets, wherein particles are exposed to the magnetic field of the magnetic assembly (magnetic field lines are shown as lines with arrows pointing from the north pole to the south pole) in more than one region (shown as dashed rectangle A), wherein the magnetic field is substantially uniform.Furthermore, the magnetic field lines are substantially parallel to each other in more than one region. Figure 4A2 of WO 2022 / 0490241 A discloses a magnetic assembly comprising two rod-shaped dipole magnets (M1, M2) having the same magnetic orientation and an iron yoke (Y), wherein the particles are exposed to the magnetic field of the magnetic assembly in more than one region (shown as dashed rectangle A) (magnetic field lines are shown as lines with arrows pointing from the North Pole to the South Pole), wherein the magnetic field is substantially uniform, and wherein the magnetic field lines are substantially parallel to each other in more than one region. Figures 6A-B of WO 2022 / 049024 A1 disclose a magnetic assembly comprising a rectangular assembly containing two rod-shaped dipole magnets (M1, M2) and two pole pieces (P1, P2), wherein the particles are exposed to the magnetic field of the magnetic assembly in more than one region (shown as dashed rectangle A) (magnetic field lines are shown as lines with arrows pointing from the North Pole to the South Pole), wherein the magnetic field is substantially uniform, and wherein the magnetic field lines are substantially parallel to each other in the region.

[0116] According to an embodiment shown, for example, in FIG8 (Examples E1-E2, during steps b') and b''), the method described herein allows for the preparation of an OEL in which both the first and second patterns exhibit dynamic movement when the OEL is tilted, the dynamic movement being a bright reflective bar moving in the vertical direction (up / down) as the OEL is tilted about a horizontal axis; wherein steps b') and b'') independently comprise exposing a radiation-curable coating composition to a rod-shaped dipole magnet having a magnetic axis oriented substantially parallel to the substrate and substantially parallel to the machine feed direction. This effect is the so-called “rolling bar” effect, as disclosed in US 2005 / 0106367. The “rolling bar” effect is based on simulating the orientation of pigment particles across a curved surface of the coating. An observer sees specular reflective areas that move away from or toward the observer as the OEL is tilted.

[0117] According to another embodiment, the method described herein allows for the preparation of an OEL in which both the first and second patterns exhibit dynamic movement when the OEL is tilted, the dynamic movement along the OEL being bright reflective vertical bars that move in a horizontal direction (left / right) when the OEL is tilted about a vertical axis; wherein steps b') and b'') independently comprise exposing a radiation-curable coating composition to a rod-shaped dipole magnet having a magnetic axis oriented substantially parallel to the substrate and substantially perpendicular to the machine feed direction. This effect is the so-called “rolling bar” effect, as disclosed in US 2005 / 0106367.

[0118] According to another embodiment,The method described herein allows for the preparation of an OEL in which both a first and a second graphic exhibit dynamic movement when the OEL is tilted, the dynamic movement of which is a bright, reflective vertical bar moving in a horizontal direction (left / right) when the OEL is tilted about a horizontal axis; wherein steps b') and b'') independently comprise exposing the radiation-curable coating composition to magnetic components such as those disclosed in WO 2020 / 160993 A1. Figures 2-5 of WO 2020 / 160993 A1 disclose a magnetic assembly comprising a) at least one dipole magnet (x40), which is a square or rectangular dipole magnet having a magnetic axis oriented substantially parallel to a substrate, and b) a combination of n groups of spaced-apart rod-shaped dipole magnets (x30-a1, x30-a2), where n is an integer equal to or greater than 1, wherein the north-south magnetic axis of each of the rod-shaped dipole magnets (x30-a1, x30-a2) is substantially parallel to the surface of the substrate, wherein, for each of the n groups, the north poles of the rod-shaped dipole magnets (x30-a1, x30-a2) point in the same direction and are substantially parallel to each other; wherein the rod-shaped dipole magnets (x30-a1, x30-a2) The vectors H1 and H2 of the magnetic axis and at least one dipole magnet (x40) are formed at an angle α in the range of about 5° to about 175° or in the range of about 185° to about 355°, wherein a combination of n groups of spaced-a1, x30-a2 rod-shaped dipole magnets is placed below or above at least one dipole magnet (x40), and wherein the combination of at least one dipole magnet (x40) and the n groups of spaced-a1, x30-b2 rod-shaped dipole magnets are substantially centered relative to each other.

[0119] According to another embodiment, the method described herein allows for the preparation of an OEL in which both the first and second patterns exhibit dynamic movement when the OEL is tilted, the dynamic movement of the OEL being bright reflective horizontal bars moving in a vertical direction (up / down) when the OEL is tilted about a horizontal axis; wherein steps b') and b'') independently comprise exposing the radiation-curable coating composition to magnetic components as disclosed in WO 2014 / 198905 A2. Figures 5-9 of WO 2014 / 198905 A2 disclose magnetic components comprising:

[0120] a) a rod-shaped dipole magnet (M1) and a pair of rod-shaped dipole magnets (M2) and (M3), the north-south axes of the rod-shaped dipole magnets (M1), (M2) and (M3) being substantially parallel to the substrate and having the same magnetic north-south direction, wherein a1) the rod-shaped dipole magnet (M1) is disposed below the substrate,And the pair of rod-shaped dipole magnets (M2) and (M3) are arranged separately below the rod-shaped dipole magnet (M1); or a2) the pair of rod-shaped dipole magnets (M2) and (M3) are arranged below the substrate and separated from each other, and the rod-shaped dipole magnet (M1) is arranged below the pair of rod-shaped dipole magnets (M2) and (M3); or

[0121] b) a pair of rod-shaped dipole magnets (M4) and (M5) and a pole piece (Y), the north-south axis of the pair of rod-shaped dipole magnets (M4) and (M5) being substantially parallel to the substrate and having the same magnetic north-south direction, the pole piece (Y) being arranged between the rod-shaped dipole magnets (M4) and the rod-shaped dipole magnets (M5); or

[0122] c) A pair of rod-shaped dipole magnets (M4) and (M5), a pole piece (Y), and a magnetic plate (M6), wherein the north-south axes of the pair of rod-shaped dipole magnets (M4) and (M5) are substantially parallel to the substrate and have the same magnetic north-south direction, and the north-south axis of the magnetic plate (M6) is substantially perpendicular to the substrate, and the pole piece (Y) is disposed between the rod-shaped dipole magnets (M4) and (M5). Particularly suitable magnetic components are those shown in Figures 5c, 6c, and 7d of WO 2014 / 198905 A2.

[0123] According to one embodiment, the method described herein allows for the preparation of an OEL in which both a first pattern and a second pattern exhibit dynamic movement when the OEL is tilted, the dynamic movement being a pattern of bright and dark areas moving as the OEL is tilted; wherein at least one of steps b') and b'') comprises exposing a radiation-curable coating composition to magnetic components disclosed in WO 2013 / 167425 A1 and WO 2021 / 083809 A1. The magnetic assembly disclosed in WO 2021 / 083809 A1 comprises at least one dipole magnet (x41) having a magnetic axis oriented substantially parallel to a substrate, and a combination comprising at least four additional dipole magnets (x31), the north poles of which point in the same direction and their magnetic axes are oriented substantially parallel to the substrate, wherein each additional dipole magnet (x31) is arranged on at least two substantially parallel straight lines αi (i=1, 2, ...) and at least two substantially parallel straight lines βj (j=1, ...). At the intersection of lines 2, ..., lines αi and βj form a grid, wherein at least two additional dipole magnets (x31) are arranged on one of lines αi, and at least two other additional dipole magnets (x31) are arranged on the other of lines αi, wherein the magnetic axes of the additional dipole magnets are oriented substantially parallel to the substantially parallel lines αi.At least one dipole magnet (x41) is disposed below a combination comprising at least four dipole magnets (x31). According to one embodiment, the vector H of each straight line αi and the magnetic axis of at least one dipole magnet (x41) is substantially parallel or substantially perpendicular to each other, and the OEL exhibits dynamic movement, which is a pattern of bright and dark areas moving when the substrate carrying the OEL is tilted, the pattern of bright and dark areas moving in the same direction as the tilting direction. According to another embodiment, the vector H of each straight line αi and the magnetic axis of at least one dipole magnet (x40) is substantially non-parallel and substantially non-perpendicular to each other's OELs. Preferably, the vector and H of each straight line αi and the magnetic axis of at least one dipole magnet (x41) form an angle γ, which is in the range of about 20° to about 70°, or in the range of about 110° to about 160°, or in the range of about 200° to about 250°, or in the range of about 290° to about 340°; and the OEL exhibits dynamic movement, which is a pattern of bright and dark areas that moves not only diagonally when the substrate carrying the OEL is tilted about the vertical / longitudinal axis, but also diagonally when the substrate carrying the OEL is tilted about the horizontal / latitude axis (in other words, the optical effect layer OEL described herein provides an optical imprint of multiple dark spots and multiple bright spots that move when the substrate carrying the OEL is tilted about two vertical axes, namely the horizontal / latitude axis and the vertical / longitudinal axis). A suitable magnetic component is WO. Those shown in Figures 6-8 of WO 2021 / 083809 A1.

[0124] According to one embodiment, the method described herein allows for the preparation of an OEL in which both the first and second patterns exhibit dynamic movement when the OEL is tilted, the dynamic movement being a pattern of light and dark areas moving as the OEL is tilted; wherein at least one of steps b') and b'') comprises exposing a radiation-curable coating composition to magnetic components such as those disclosed in WO 2021 / 083808 A1. The magnetic assembly disclosed in WO 2021 / 083808 A1 comprises at least one dipole magnet (x41) having a magnetic axis oriented substantially parallel to a substrate and a combination comprising at least four additional dipole magnets (x31), the north poles of which point in the same direction and their magnetic axes are oriented substantially parallel to the substrate, wherein each additional dipole magnet (x31) is arranged 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, ...), the lines αi and βj forming a grid, wherein at least two additional dipole magnets (x31) are arranged on one of the lines αi.Furthermore, at least two other additional dipole magnets (x31) are arranged on the other of the lines αi, wherein the magnetic axes of the additional dipole magnets (x31) are substantially parallel to the substrate and oriented along line αi, wherein at least one dipole magnet (x41) is arranged below a combination comprising at least four first dipole magnets (x31), wherein on each line αi, and on each line βj, the north poles of adjacent additional dipole magnets (x31) point in opposite directions, wherein the vector H of the magnetic axes of each line αi and at least one dipole magnet (x41) is substantially non-parallel and substantially non-perpendicular to each other, preferably wherein the vector sum H of the magnetic axes of each line αi and at least one dipole magnet (x41) forms an angle γ, said angle γ Within a range of approximately 20° to approximately 70°, or approximately 110° to approximately 160°, or approximately 200° to approximately 250°, or approximately 290° to approximately 340°; and the OEL exhibits dynamic movement, which is a pattern of bright and dark areas that moves not only diagonally when the substrate carrying the OEL is tilted about the vertical / longitudinal axis, but also diagonally when the substrate carrying the OEL is tilted about the horizontal / transverse axis (in other words, the optical effect layer OEL described herein provides an optical imprint of multiple dark spots and multiple bright spots that move when the substrate carrying the OEL is tilted about two vertical axes, namely the horizontal / transverse axis and the vertical / longitudinal axis). Suitable magnetic components are those shown in Figures 5-7 of WO 2021 / 083808 A1. Instruction manual 19 / 43 pages 22 CN 122422064 A

[0125] According to one embodiment, the method described herein allows for the preparation of an OEL, wherein both the first and second patterns exhibit dynamic movement when the OEL is tilted, the dynamic movement being a ring-shaped body moving when the OEL is tilted; wherein steps b') and b'') independently comprise exposing the radiation-curable coating composition to those magnetic components disclosed in WO 2014 / 108404 A2. The magnetic assembly disclosed in WO 2014 / 108404 A2 comprises a) at least one dipole magnet having a magnetic axis oriented substantially perpendicular to a substrate and one or more pole pieces, said one or more pole pieces being disposed below and in contact with and / or spaced apart from and laterally surrounding the at least one dipole magnet (see, for example, Figures 3-5 of WO 2014 / 108404 A2); b) at least one dipole magnet being a ring magnet with radial magnetization (i.e., its magnetic north-south axis extending radially from the center of the ring magnet to the outer periphery) (see, for example, Figure 6 of WO 2014 / 108404 A2); or c) at least one dipole magnet being three or more dipole magnets arranged in a ring with radial magnetization (i.e.,The magnetic axes of each of the three or more dipole magnets are oriented substantially parallel to the substrate, and their magnetic axes are aligned such that they extend substantially radially from the center of symmetry of the annular arrangement, wherein the north-south directions of the three or more dipole magnets are all pointed towards or entirely away from the center of symmetry (see, for example, Figure 7 of WO 2014 / 108404 A2). WO 2014 / 108404 A2 also discloses a rotatable magnetic assembly comprising a) at least two rod-shaped dipole magnets whose magnetic axes are substantially parallel to the substrate and have the same magnetic direction (Figure 9) or opposite magnetic directions (see Figure 11 of WO 2014 / 108404 A2), or b) at least two rod-shaped dipole magnets whose magnetic axes are substantially perpendicular to the substrate and have opposite magnetic directions (see Figure 10 of WO 2014 / 108404 A2).

[0126] According to an embodiment shown, for example, in FIG9 (Examples E3-E4, during steps b') and b''), the method herein allows for the preparation of an OEL, wherein both the first and second patterns exhibit dynamic movement when the OEL is tilted, the dynamic movement being a multi-ringed body moving when the OEL is tilted; wherein steps b') and b'') independently comprise exposing the radiation-curable coating composition to those magnetic components disclosed in WO 2014 / 108303 A2. The magnetic component disclosed in WO 2014 / 108303 A2 comprises one of the following:

[0127] a) at least one dipole magnet and a pole piece (x60), said at least one dipole magnet being a ring magnet defining a ring and having a magnetic axis oriented substantially perpendicular to the substrate, said pole piece (x60) being disposed below the at least one dipole magnet and within the ring of said at least one dipole magnet and having one or more protrusions disposed within the ring of said at least one dipole magnet (see, for example, Figures 3-5 of WO 2014 / 108303 A2); or

[0128] (b) Having at least one dipole magnet oriented substantially perpendicular to a magnetic axis of the substrate, another dipole magnet oriented substantially perpendicular to a magnetic axis of the substrate, and two or more pole pieces, wherein the at least one dipole magnet and the other magnet have the same magnetic direction and are disposed at different distances from the substrate, wherein the two or more pole pieces are arranged in the space between the magnets and in contact with them, and wherein at least one of the two or more pole pieces forms one or more annular protrusions around a central region.At least one dipole magnet is arranged in the central region (see, for example, FIG. 6 of WO 2014 / 108303 A2); or

[0129] c) having at least one dipole magnet oriented substantially perpendicular to the magnetic axis of the substrate, a plate-shaped pole piece disposed below and in contact with the at least one dipole magnet, and one or more annular pole pieces disposed on top of the at least one dipole magnet, wherein the central pole piece of the one or more annular pole pieces is in contact with the at least one dipole magnet, and wherein the plate-shaped pole piece may include one or more spaced protrusions that laterally surround the at least one dipole magnet (see, for example, FIG. 7 of WO 2014 / 108303 A2). WO 2014 / 108303 A2 also discloses a rotatable magnetic assembly comprising a) at least two rod-shaped dipole magnets whose magnetic axes are substantially perpendicular to the substrate (see Figures 8-10 and 13-14 of WO 2014 / 108303 A2), or comprising b) at least four rod-shaped dipole magnets whose magnetic axes are substantially parallel to the substrate (see Figures 11, 12 and 15 of WO 2014 / 108303 A2). Instructions 20 / 43 pages 23 CN 122422064 A

[0130] According to one embodiment, the method described herein allows for the preparation of an OEL, wherein both the first and second patterns exhibit dynamic movement when the OEL is tilted, the dynamic movement being a ring-shaped body whose size changes as the OEL is tilted; wherein steps b') and b'') independently comprise exposing the radiation-curable coating composition to those magnetic components disclosed in WO 2017 / 064052 A1, WO 2017 / 080698 A1 and WO 2017 / 148789 A1. The magnetic components disclosed in WO 2017 / 064052 A1, WO 2017 / 080698 A1 and WO 2017 / 148789 A1 comprise one of:

[0131] a) at least one dipole magnet (x40), which is a single rod-shaped dipole magnet having a north-south magnetic axis substantially parallel to the substrate or a combination of two or more rod-shaped dipole magnets having a obtained north-south magnetic axis substantially parallel to the substrate; and b) a ring-shaped magnetic field generating device (x30), which is a single ring-shaped dipole magnet having a north-south magnetic axis substantially perpendicular to the substrate or a combination of two or more dipole magnets arranged in a ring and having a obtained north-south magnetic axis substantially perpendicular to the substrate (see, for example, Figures 1-4 of WO 2017 / 064052 A1), or

[0132] a) At least one dipole magnet (x40), which is a single dipole magnet having a magnetic axis substantially parallel to the substrate or a combination of two or more rod-shaped dipole magnets.a) Each of two or more rod-shaped dipole magnets has a magnetic axis substantially parallel to the substrate and has the same magnetic field direction; b) a ring-shaped magnetic field generating device (x31), which is a single ring-shaped dipole magnet having a magnetic axis substantially perpendicular to the substrate or a combination of two or more dipole magnets arranged in a ring, each of the two or more dipole magnets having a magnetic axis substantially perpendicular to the substrate and having the same magnetic field direction; and c) a single dipole magnet (x32) having a magnetic axis substantially perpendicular to the substrate or two or more dipole magnets, each of the two or more dipole magnets having a magnetic axis substantially perpendicular to the substrate and having the same magnetic field direction; and / or one or more pole pieces (see, for example, Figures 1-12 of WO 2017 / 080698 A1), or

[0133] a) at least one dipole magnet (x40), which is a single rod-shaped dipole magnet having a magnetic axis substantially parallel to the substrate or a combination of two or more rod-shaped dipole magnets, each of the two or more rod-shaped dipole magnets having a magnetic axis substantially parallel to the substrate and having the same magnetic field direction; b) a ring-shaped magnetic field generating device (x31), which is a single ring-shaped magnet or a combination of two or more dipole magnets (x31) arranged in a ring, the ring-shaped magnetic field generating device having radial magnetization; and c) a single dipole magnet (x32) having a magnetic axis substantially perpendicular to the substrate or a single dipole magnet (x32) having a magnetic axis substantially parallel to the substrate or two or more dipole magnets (x32), the two or more dipole magnets having a magnetic axis substantially parallel to the substrate, each of the two or more rod-shaped dipole magnets having a magnetic axis substantially parallel to the substrate and having the same magnetic field direction; Each of the bodies (x32) has a magnetic axis substantially perpendicular to the substrate, wherein when the north pole of a single ring magnet (x31) or two or more dipole magnets (x31) forming the ring magnetic field generating device points to the outer periphery of the ring magnetic field generating device, the north pole of the single dipole magnet (x32) or the north pole of at least one of the two or more dipole magnets (x32) points to the substrate, or when the south pole of a single ring magnet (x31) or two or more dipole magnets (x31) forming the ring magnetic field generating device points to the outer periphery of the ring magnetic field generating device (x31), the south pole of the single dipole magnet (x32) or the south pole of at least one of the two or more dipole magnets (x32) points to the substrate (see, for example, Figures 1-14 of WO 2017 / 148789 A1).

[0134] According to one embodiment, the method described herein allows for the preparation of an OEL, wherein both the first and second patterns exhibit dynamic movement when the OEL is tilted, the dynamic movement being a ring-shaped body whose shape changes as the OEL is tilted; wherein steps b') and b'') independently comprise exposing the radiation-curable coating composition to magnetic components such as those disclosed in WO 2018 / 054819 A1. In particular,The magnetic assembly disclosed in WO 2018 / 054819 A1 includes a ring-shaped magnetic field generating device (x31), which is a single ring magnet (x31) or a combination of two or more dipole magnets (x31) arranged in a ring, the ring-shaped magnetic field generating device (x31) having radial magnetization; and a single dipole magnet (x32) or two or more dipole magnets (x32) having a magnetic axis substantially perpendicular to the surface of the substrate, each of the two or more dipole magnets (x32) having a magnetic axis substantially perpendicular to the surface of the substrate, wherein the single dipole magnet (x32) or two or more dipole magnets are described on pages 21 / 43 of the specification, CN 122422064 A. A polar magnet (x32) is located inside, inside, or above a portion of a ring defined by a single ring magnet (x31), or inside, inside, or above a portion of a ring defined by two or more dipole magnets (x31) arranged in a ring. When the north pole of the single ring magnet (x31) or two or more dipole magnets (x31) forming the ring magnetic field generating device (x31) points towards the outer periphery of the ring magnetic field generating device (x31), the south pole of the single dipole magnet (x32) or the south pole of each of the two or more dipole magnets (x32) points towards the substrate surface. Alternatively, when the south pole of the single ring magnet (x31) or two or more dipole magnets (x31) forming the ring magnetic field generating device (x31) points towards the outer periphery of the ring magnetic field generating device (x31), the north pole of the single dipole magnet (x32) or the north pole of each of the two or more dipole magnets (x32) points towards the substrate surface.

[0135] According to one embodiment, the method described herein allows for the preparation of an OEL, wherein both the first and second patterns exhibit dynamic movement when the OEL is tilted, the dynamic movement being a crescent shape that moves and rotates when the OEL is tilted; wherein steps b') and b'') independently comprise exposing the radiation-curable coating composition to magnetic components such as those disclosed in WO 2019 / 215148 A1. The magnetic assembly disclosed in WO 2019 / 215148 A1 includes a) a first magnetic field generating device (x30) having a north-south magnetic axis substantially perpendicular to the surface of a substrate and having a length L1; b) a second magnetic field generating device (x40) having a north-south magnetic axis substantially perpendicular to the substrate and having a length L3; and c) a flat pole piece (x50) having no protrusions or projections extending beyond the surface of the pole piece and having a length L5, wherein the first and second magnetic field generating devices have the same magnetic field direction, wherein the first magnetic field generating device faces the substrate and is disposed above the flat pole piece, wherein the second magnetic field generating device faces the environment and is disposed below the flat pole piece, and wherein the length L1 of the first magnetic field generating device is less than the length L3 of the second magnetic field generating device.The length L1 of the first magnetic field generating device is less than the length L5 of the flat electrode, and the length L3 of the second magnetic field generating device is less than the length L5 of the electrode (see, for example, Figures 1-12 of WO 2017 / 148789 A1).

[0136] According to one embodiment, the method described herein allows for the preparation of an OEL in which both the first and second patterns exhibit dynamic movement when the OEL is tilted, the dynamic movement being a ring surrounded by a substantially annular body whose shape and / or brightness changes as the OEL is tilted; wherein steps b') and b'') independently comprise exposing a radiation-curable coating composition to those magnetic components disclosed in WO 2020 / 193009 A1. The magnetic assembly disclosed in WO 2020 / 193009 A1 comprises a) a combination of three or more first dipole magnets (x31-ai), each of which is centrally disposed on a ring in a plane parallel to the substrate, wherein the magnetic axis of the first dipole magnet (x31-ai) is oriented substantially parallel to the substrate, and b) at least one second dipole magnet (x41) having a magnetic axis oriented substantially perpendicular to the substrate and arranged such that the projection of its center onto the substrate is located at a projection point within the ring, wherein the at least one second dipole magnet (x41) is disposed above the combination of the three or more first dipole magnets (x31-ai), wherein an angle αi is formed between each vector (x1, x2, ...) and the vector (x31, x41, ...) of the magnetic axis of the corresponding first dipole magnet (x31-ai). When measured in the counterclockwise direction, all angles αi are in the range of about 20° to about 160° or about 200° to about 340°, and each of the first dipole magnets (x31-ai) is disposed at a first distance (Yi) on the substrate between the projection point and the center of the first dipole magnet (x31-ai) (see, for example, Figures 2-9 in WO 2020 / 193009 A1).

[0137] According to one embodiment, the method described herein allows for the preparation of an OEL in which both the first and second patterns exhibit dynamic movement when the OEL is tilted, the dynamic movement being a change from dark to light in two regions when the OEL is tilted (the effect is a so-called flip-flop); wherein steps b') and b'') independently comprise exposing a radiation-cured coating composition to those magnetic components disclosed in Figures 1, 3, and 6 of US 2005 / 0106367.

[0138] According to one embodiment, the method described herein allows for the preparation of an OEL in which both the first and second patterns exhibit dynamic movement when the OEL is tilted.The dynamic movement is a comet-shaped point rotating around the center of rotation when the OEL is tilted, wherein steps b') and b'') independently include exposing the radiation-curable coating composition to those magnetic components disclosed in WO 2019 / 038371 A1, WO 2019 / 038370 A1, and WO 2019 / 038369 A1. The magnetic components disclosed in WO 2019 / 038371 A1, WO 2019 / 038370 A1, and WO 2019 / 038369 A1 comprise at least one of the following:

[0139] -a) a first magnetic field generating device (x30) and b) a second magnetic field generating device (x40), wherein the first magnetic field generating device (x30) and the second magnetic field generating device (x40) have magnetic axes that are inclined to each other, wherein the magnetic axis of the first magnetic field generating device (x30) is substantially perpendicular to the rotation axis, and the magnetic axis of the second magnetic field generating device (x40) is substantially perpendicular to the rotation axis, and wherein the projection of the magnetic axis of the first magnetic field generating device (x30) and the projection of the magnetic axis of the second magnetic field generating device (x40) are perpendicular to the rotation axis along the rotation axis. An angle (Ω) is formed on the plane, the angle (Ω) being in the range of about 5° to about 175° or in the range of about -5° to about -175°, and wherein the first magnetic field generating device (x30) comprises a rod-shaped dipole magnet whose north-south magnetic axis is substantially perpendicular to the axis of rotation; or two or more rod-shaped dipole magnets, each of which has a north-south magnetic axis substantially perpendicular to the axis of rotation, and all of the two or more rod-shaped dipole magnets having the same magnetic field direction; or a ring-shaped dipole magnet whose north-south magnetic axis is substantially perpendicular to the axis of rotation; Or a disc-shaped dipole magnet nested inside a ring-shaped dipole magnet, wherein the north-south magnetic axis of each of the disc-shaped dipole magnet and the ring-shaped dipole magnet is substantially perpendicular to the axis of rotation and has the same magnetic field direction; or two or more nested ring-shaped dipole magnets, wherein the north-south magnetic axis of each of the two or more nested ring-shaped dipole magnets is substantially perpendicular to the axis of rotation, and all of the two or more nested ring-shaped magnets have the same magnetic field direction; and wherein the second magnetic field generating device (x40) comprises a disc-shaped dipole magnet whose north-south magnetic axis is substantially perpendicular to the axis of rotation; or a ring-shaped dipole magnet whose north-south magnetic axis is substantially perpendicular to the axis of rotation; or a rod-shaped dipole magnet whose north-south magnetic axis is substantially perpendicular to the axis of rotation;

[0140] a) a first magnetic field generating device (x30) and b) a second magnetic field generating device (x40), wherein the first magnetic field generating device (x30) comprises at least a pair of two rod-shaped dipole magnets (x31) that are at least partially or completely embedded in a support base (x32), wherein the north-south magnetic axis of each of the rod-shaped dipole magnets (x31) is substantially parallel to the axis of rotation.At least one pair of the two rod-shaped dipole magnets (x31) have opposite magnetic field directions and are arranged symmetrically along line (α) about the rotation axis, and

[0141] the second magnetic field generating device (x40) includes b1) a disk-shaped dipole magnet (x41) whose north-south magnetic axis is substantially perpendicular to the rotation axis, b2) a ring-shaped dipole magnet (x41) whose north-south magnetic axis is substantially perpendicular to the rotation axis, b3) a rod-shaped dipole magnet (x41) whose north-south magnetic axis is substantially perpendicular to the rotation axis and is arranged on the rotation axis, and / or b4) at least one pair of two rod-shaped dipole magnets (x41), each of which has a north-south magnetic axis substantially parallel to the rotation axis. At least one pair of the two rod-shaped dipole magnets (x41) have opposite magnetic field directions and are arranged symmetrically along line (β) about the rotation axis. Arranged in a symmetrical configuration, the projection of the line (α) of at least one pair of rod-shaped dipole magnets (x31) of the first magnetic field generating device (x30) and the projection of the magnetic axis of the second magnetic field generating device (x40) form an angle (Ω) along the rotation axis in a plane perpendicular to the rotation axis, said angle (Ω) being in the range of about 5° to about 175° or in the range of about -5° to about -175°; or

[0142] - A magnetic field generating device (x30) comprising a disk-shaped dipole magnet (x31) whose north-south magnetic axis is substantially perpendicular to the rotation axis; or an annular, preferably loop-shaped dipole magnet (x31) whose north-south magnetic axis is substantially perpendicular to the rotation axis; or a rod-shaped dipole magnet (x31) whose north-south magnetic axis is substantially perpendicular to the rotation axis and arranged on the rotation axis, wherein the disk-shaped dipole magnet (x31), annular, preferably loop-shaped dipole magnet (x31), or rod-shaped dipole magnet (x31) of the magnetic field generating device (x30) is included up to page 23 / 43 of the specification. 26 CN 122422064 A At least one pair of indentations (I) and / or at least one pair of voids (V) and / or at least one pair of protrusions (P), wherein at least one pair of indentations (I), at least one pair of voids (V) and / or at least one pair of protrusions (P) are positioned as follows: symmetrical about the axis of rotation, and with respect to the north-south magnetic axis of the disk-shaped dipole magnet (x31), annular, preferably ring-shaped dipole magnet (x31) or rod-shaped dipole magnet (x31) perpendicular to the magnetic field generating device (x30), and including a mirror asymmetry of the axis of rotation.

[0143] According to one embodiment, the method described herein allows for the preparation of OEL, wherein both steps b') and b'') comprise independently exposing the radiation-curable coating composition to a combined magnetic field of a combination of a magnetic component described later for biaxial orientation of pigment particles and a soft magnetic plate comprising one or more indentations (I) and / or one or more voids (V) and / or one or more protrusions (P). The soft magnetic plate described herein comprises one or more soft magnetic materials.This refers to materials with low coercivity and high permeability μ. Their coercivity, as measured according to IEC 60404-1:2000, is below 1000 Am⁻¹ to allow for rapid magnetization and demagnetization. Suitable soft magnetic materials have a maximum relative permeability μRmax of at least 5, where the relative permeability μR is the permeability of the material μ relative to the permeability of free space μ₀ (μR = μ / μ₀) (Magnetic Materials, Fundamentals and Applications, 2nd ed., Nicola A. Spaldin, pp. 16-17, Cambridge University Press, 2011). Soft magnetic materials are described in, for example, the following handbooks: (1) Handbook of Condensed Matter and Materials Data, Chapter 4.3.2, Soft Magnetic Materials, pp. 758-793, and Chapter 4.3.4, Magnetic Oxides, pp. 811-813, Springer, 2005; (2) Ferromagnetic Materials, Volume 1, Iron, Cobalt and Nickel, pp. 1-70, Elsevier, 1999; (3) Ferromagnetic Materials, Volume 2, Chapter 2, Soft Magnetic Metallic Materials, pp. 55-188, and Chapter 3, Ferrites for Non-Microwave Applications, pp. 189-241, Elsevier, 1999; (4) Electric and Magnetic Properties of Metals, C. Moosbrugger, Chapter 8, Soft Magnetic Materials, pp. 196-209, ASM International, 2000; (5) Handbook of modern Ferromagnetic Materials, Chapter 9, High-Permeability High-Frequency Metal Strips, pp. 155-182, Kluwer Academic Publishers, 2002; and (6) Smithells Metals Reference Book, Chapter 20.3, Soft Magnetic Materials, pp. 20-9 to 20-16, Butterworth-Heinemann Ltd, 1992. The soft magnetic plates described herein can be plates made of one or more metals, alloys, or compounds with high permeability (hereinafter referred to as "soft magnetic metal plates").Alternatively, it may be a plate made of a composite material containing soft magnetic particles dispersed in a non-magnetic material (hereinafter referred to as a "soft magnetic composite plate"). According to one embodiment, the soft magnetic metal plate described herein is made of one or more soft magnetic metals or alloys that can be readily used as sheets or wires. Preferably, the soft magnetic metal plate described herein is made of one or more materials selected from the group consisting of iron, cobalt, nickel, nickel-molybdenum alloys, nickel-iron alloys (permalloy or supermalloy-type materials), cobalt-iron alloys, cobalt-nickel alloys, iron-nickel-cobalt alloys (ferric-nickel-cobalt type materials), Heusler-type alloys (such as Cu2MnSn or Ni2MnAl), low-silicon steel, low-carbon steel, ferrosilicon (electrical steels), iron-aluminum alloys, iron-aluminum-silicon alloys, amorphous metal alloys (such as Metglas®, iron-boron alloys, etc.), nanocrystalline soft magnetic materials (such as Vitroperm®), and combinations thereof, more preferably the group consisting of iron, cobalt, nickel, low-carbon steel, ferrosilicon, nickel-iron alloys, and cobalt-iron alloys and combinations thereof.

[0144] FIG4B illustrates a method in which orientation step b)(b') and / or b'') independently include a magnetic orientation step in which an assembly comprising a substrate (410) comprising the coating (420) described herein is placed on a first magnetic assembly (430-a), and the assembly is simultaneously moved in the vicinity of a static second magnetic assembly (430-b), wherein the first magnetic assembly (430-a) is mounted on a transfer device as a rotating magnetic cylinder, and the second magnetic assembly (430-b) is arranged in the vicinity of the rotating magnetic cylinder. According to one embodiment, such as that shown in Figure 4B, the method described herein allows for the preparation of OEL, wherein steps b)(b') and / or b'') both independently comprise the following steps: placing a substrate (410) carrying a radiation-curable coating composition in the form of a coating (420) on a first magnetic component (430-a) providing a first magnetic field vector component, the first magnetic component being mounted on a rotating magnetic cylinder, thereby subjecting the sheet-like magnetic or magnetizable pigment particles to the first magnetic field vector component, and simultaneously moving the substrate (410) carrying the coating (420) and the first magnetic component (430-a) near a static second magnetic component (430-b), the second magnetic component (430-b) providing a second magnetic field vector component, thereby subjecting the sheet-like magnetic or magnetizable pigment particles to a time-dependent synthetic magnetic field formed by the first and second magnetic field vector components, so that at least a portion of the sheet-like magnetic or magnetizable pigment particles are biaxially oriented. According to one embodiment,The ratio of the magnetic flux density of the first magnetic component (430-a) to the magnetic flux density of the static second magnetic component (430-b) is less than about 4.0, preferably less than about 1.9, and more preferably between about 1.5 and about 0.5. The first magnetic component (430-a), on which a substrate (410) on which a carrier coating (420) is placed, is exposed to a magnetic component preferably selected from the above-described magnetic component for uniaxial orientation of pigment particles and the above-described soft magnetic plate. The second magnetic component (430-b) is preferably selected from the above-described magnetic component for biaxial orientation of pigment particles. Such a method is disclosed in WO 2019 / 14142 A1 and WO 2019 / 141453 A1.

[0145] According to one embodiment shown, for example, in Figure 5-1 and used in embodiments E1-E4 provided therein, the method described herein comprises a first set of steps (1) and a second set of steps (2), wherein the magnetic orientation step b') of the first set of steps (1) and the magnetic orientation step b'') of the second set of steps (2) independently comprise two magnetic orientation steps, each comprising two steps: a first orientation step (b'-1 and b''-1, respectively) to biaxially oriented the sheet-like magnetic or magnetizable pigment particles as described herein, followed by a second orientation step to reorient the sheet-like magnetic or magnetizable pigment particles as described herein (b'-2 and b''-2, respectively), wherein the particles will be supported on their first side A substrate (510) bearing a first coating (520') is exposed to the magnetic field of a magnetic component (530'-a) and subsequently to the magnetic field of a magnetic component (530'-b), the two magnetic components (530'-a and 530'-b) being located on a second side of the substrate (i.e., the side without the first coating (520')). A substrate (510) bearing a second coating (520'') on its second side is exposed to the magnetic field of the magnetic component (530''-a) and subsequently to the magnetic field of the magnetic component (530''-b), the two magnetic components (530''-a and 530''-b) being located on a first side of the substrate (i.e., the side containing the first coating (520') in a cured state). On one side of the substrate (510), and wherein magnetic components 530'-a and 530''-a are the same components, specifically two identical individual objects, and magnetic components 530'-b and 530''-b are the same components, specifically two identical individual objects, to produce first and second magnetic patterns that are mirror-symmetrical relative to the substrate (510).

[0146] Figure 5-2 (not drawn to scale) illustrates a method in which orientation step b (is step b') and b'')) comprises two magnetic orientation steps, wherein the radiation-curable coating composition described herein is first exposed to the magnetic field of the first magnetic component (530-a) and subsequently exposed to the magnetic field of the second magnetic component (530-b).The second magnetic component (530-b) is mounted on a rotating magnetic cylinder. Figure 5-3 (not drawn to scale) illustrates a method in which the orientation steps (b') and b'') comprise two magnetic orientation steps, wherein the radiation-curable coating composition described herein is exposed to the magnetic field of the magnetic component (530-a), and subsequently exposed to the combined magnetic field of the second magnetic component (530-b) and the third magnetic component (530-c), wherein the second magnetic component (530-b) is mounted on the rotating magnetic cylinder, and the third magnetic component (530-c) is disposed in the vicinity of the rotating magnetic cylinder. A suitable method in which the orientation step b) comprises two magnetic orientation steps is disclosed in WO 2015 / 086257 A1.

[0147] According to one embodiment, for example, shown in FIG. 6, the method herein comprises a first set of steps (1) and a second set of steps (2), wherein the magnetic orientation step b') of the first set of steps (1) and the magnetic orientation step b'') of the second set of steps (2) are independently two magnetic orientation steps, each step independently comprising two steps: a first orientation step (b'-1 and b''-1, respectively) to biaxially orient the sheet-like magnetic or magnetizable pigment particles as described herein, followed by a second orientation step to reorient the sheet-like magnetic or magnetizable pigment particles as described herein (b'-2 and b''-2, respectively), wherein a substrate (610) bearing a first coating (620') on its first side is exposed to the magnetic field of a magnetic component (630'-a), and subsequently exposed to the combined magnetic field of magnetic components (630'-b) and magnetic components (630'-c), the magnetic components (630'-a, 630'-b, 630'-c) are located on the second side of the substrate (i.e., the side without the first coating (620'), and wherein the substrate (610) bearing the second coating (620'') on its second side is exposed to the magnetic field of the magnetic component (630''-a), and subsequently exposed to the combined magnetic field of the magnetic components (630''-b) and (630''-c), the magnetic components (630''-a, 630''-b and 630''-c) being located on the first side of the substrate (i.e., the side containing the first coating (620') in a cured state), and wherein magnetic components 630'-a and 630''-a are the same component, specifically two identical separate objects, magnetic components 630'-b and 630''-b are the same component, specifically two identical separate objects, and magnetic components 630'-c and 630''-c are the same component, specifically two identical separate objects.To produce first and second magnetic patterns that are mirror-symmetric relative to the substrate (610).

[0148] The first orientation step (b-1) of biaxially oriented the sheet-like magnetic or magnetizable pigment particles as described herein is preferably performed using the magnetic assembly described below, and the second orientation step (b-2) of reorienting the pigment particles is preferably performed using the magnetic assembly described above.

[0149] In contrast to uniaxial orientation in which the sheet-like magnetic or magnetizable pigment particles are oriented in such a way that only their principal axes are constrained by a magnetic field, biaxial orientation means oriented such that the sheet-like magnetic or magnetizable pigment particles are constrained by both of their principal axes. In contrast to needle-like pigment particles, which can be considered as one-dimensional particles, sheet-like pigment particles have an X-axis and a Y-axis that define the main extension plane of the particle. In other words, sheet-like pigment particles can be considered as two-dimensional particles because of their large aspect ratio, as can be seen in FIG2. As shown in FIG2, sheet-like pigment particles can be considered as two-dimensional structures in which dimensions X and Y are substantially larger than dimension Z. Sheet-like pigment particles are also referred to in the art as flat particles or flakes. Such pigment particles can be described as having a principal axis X corresponding to the longest dimension passing through the pigment particle and a second axis Y perpendicular to X, also located within the pigment particle. Biaxial orientation results in the sheet-like magnetic or magnetizable pigment particles having two constrained principal axes, meaning that adjacent sheet-like magnetic pigment particles in biaxial orientation are spatially close to each other and substantially parallel to each other. In other words, biaxial orientation aligns the planes of the sheet-like magnetic or magnetizable pigment particles such that the planes of the pigment particles are oriented substantially parallel to the planes of adjacent (in all directions) sheet-like magnetic or magnetizable pigment particles.

[0150] The biaxially oriented sheet-like magnetic or magnetizable pigment particles described herein consist of sheet-like magnetic or magnetizable pigment particles forming a sheet-like structure, whose X and Y axes are preferably substantially parallel to the substrate (x10) surface and are planarized in said two dimensions.

[0151] According to another embodiment, the magnetic component described below allows for biaxial orientation of the sheet-like magnetic or magnetizable pigment particles described herein, such that the sheet-like magnetic or magnetizable pigment particles have a first axis substantially parallel to the surface of the substrate (x10) in the XY plane and a second axis substantially perpendicular to the first axis at a substantially non-zero elevation angle to the surface of the substrate.

[0152] According to another embodiment, the magnetic component described below allows for biaxial orientation of the sheet-like magnetic or magnetizable pigment particles described herein, such that the XY plane of the sheet-like magnetic or magnetizable pigment particles is substantially parallel to the surface of an imaginary sphere.

[0153] Suitable magnetic components for biaxially oriented sheet-like magnetic or magnetizable pigment particles described herein are provided below as non-limiting examples.

[0154] According to, for example, the magnetic component (730) used during steps b') and b'') of one embodiment shown in FIG. 7,The steps b') and b'') respectively independently include exposing the radiation-curable coating composition to those magnetic components disclosed in WO 2021 / 239607 A1. The magnetic components disclosed in WO 2021 / 239607 A1 comprise: Specification 26 / 43 pages 29 CN 122422064 A

[0155] a) at least a first group (S1) and a second group (S2), each of the first group (S1) and the second group (S2) comprising: i) a first rod-shaped dipole magnet (x31) having a first thickness (L1), a first length (L4) and a first width (L5), and having its magnetic axis oriented substantially parallel to the substrate, and ii) having a second thickness (L2), a second length (L6) and a second width (L7). Two second rod-shaped dipole magnets (x32a and x32b) have their uppermost surfaces flush with each other, and their magnetic axes are oriented substantially perpendicular to the substrate. The first rod-shaped dipole magnet (x31) of the first group (S1) has a magnetic direction opposite to that of the first rod-shaped dipole magnet (x31) of the second group (S2). The first rod-shaped dipole magnets of the first group (S1) and the first rod-shaped dipole magnets of the second group (S2) have magnetic directions opposite to those of the first rod-shaped dipole magnets. The pole magnets (x31) are spaced apart by a first distance (d1). The first rod-shaped dipole magnets (x31) of the first group (S1) and the first rod-shaped dipole magnets (x31) of the second group (S2) have substantially the same thickness (L1), first length (L4), and first width (L5). Furthermore, the two second rod-shaped dipole magnets (x32a and x32b) of the first group (S1) and the two second rod-shaped dipole magnets (x32a and x32b) of the second group (S2) are spaced apart by a first distance (d1). 2b) Having substantially the same second thickness (L2), second length (L6), and second width (L7), wherein the first rod-shaped dipole magnets (x31) and second rod-shaped dipole magnets (x32a and x32b) of each of the first group (S1) and the second group (S2) are aligned to form a column, wherein the first rod-shaped dipole magnets (x31) of the first group (S1) and the second group (S2) are respectively placed between and spaced apart from the second rod-shaped dipole magnets (x32a and x32b), the first width (L5) and the second length (L6) are substantially the same, the north pole of one of the second rod-shaped dipole magnets (x32a and x32b) of each of the first group (S1) and the second group (S2) points to the first plane, and the north pole of the first rod-shaped dipole magnet (x31) points to said second rod-shaped dipole magnet (x32a and x32b), and the first group (S1) and the second group (S2) The south pole of each of the two second rod-shaped dipole magnets (x32a and x32b) points towards the first plane.And the south pole of the first rod-shaped dipole magnet (x31) points to the other second rod-shaped dipole magnet (x32a and x32b); and

[0156] b) the first pair (P1) of third rod-shaped dipole magnets (x33a and x33b) having a third thickness (L3), a third length (L8) and a third width (L9), and their magnetic axes are oriented substantially parallel to the substrate, the second width (L7) of the two second rod-shaped dipole magnets (x32a and x32b) of the first group (S1) and the second group (S2) having a value substantially the same as the third width (L9) of the third rod-shaped dipole magnets (x33a and x33b), each of the third rod-shaped dipole magnets (x33a and x33b) having a value substantially the same as the third width (L9) of the two second rod-shaped dipole magnets (x32a and x32b) of the first group (S1) and the second rod-shaped dipole magnets (x32a and x32b) of the second group (S2). Aligned to form two lines, the third rod-shaped dipole magnets (x33a and x33b) are placed between and spaced apart from the corresponding second rod-shaped dipole magnets (x32a and x32b) by a third distance (d3). When the north pole of one of the second rod-shaped dipole magnets (x32a and x32b) points toward the substrate, the north pole of the third rod-shaped dipole magnets (x33a and x33b) points toward the second rod-shaped dipole magnets (x32a and x32b), respectively; or when the south pole of one of the second rod-shaped dipole magnets (x32a and x32b) points toward the substrate, the south pole of the third rod-shaped dipole magnets (x33a and x33b) points toward the second rod-shaped dipole magnets (x32a and x32b), respectively.

[0157] According to one embodiment, the method described herein includes steps b') and b''), which independently include exposing the radiation-curable coating composition to magnetic components as described in EP 2 157 141 A1. The magnetic components disclosed in EP 2 157 141 A1 provide a magnetic field that changes the orientation of sheet-like magnetic or magnetizable pigment particles as they move through the component, forcing the sheet-like magnetic or magnetizable pigment particles to oscillate rapidly until the two principal axes become parallel to the substrate, i.e., the sheet-like magnetic or magnetizable pigment particles oscillate until they reach a stable sheet-like form, wherein their X-axis and Y-axis are parallel to the substrate and are planarized in said two dimensions. As shown in Figure 5 of EP 2 157 141, the magnetic assembly comprises a linear arrangement of at least three magnets positioned in an alternating or zigzag pattern on opposite sides of the feed path, wherein magnets on the same side of the feed path have the same polarity, the polarity being opposite to that of magnets on opposite sides of the alternating feed path. When the flake-like magnetic or magnetizable pigment particles in the coating composition move past the magnets,An arrangement of at least three magnets provides a predetermined change in the field direction (direction of movement: arrow). According to one embodiment, page 27 / 43 of 30 CN 122422064 A, the magnetic assembly includes a) a first magnet and a third magnet on a first side of the feed path, and b) a second magnet between the first and third magnets on a second opposite side of the feed path, wherein the first and third magnets have the same polarity, and wherein the second magnet has a polarity complementary to the first and third magnets. According to another embodiment, the magnetic assembly further includes a fourth magnet on the same side of the feed path as the second magnet, having the polarity of the second magnet and complementary to the polarity of the third magnet.

[0158] According to one embodiment, the method herein includes steps b') and b''), which independently include exposing a radiation-curable coating composition to a magnetic assembly comprising a linear permanent magnet Helbeck array, i.e., an assembly comprising a plurality of magnets and a cylindrical device having different magnetization directions. A detailed description of Halbach permanent magnets is given by ZQ Zhu and D. Howe (Halbach permanent magnet machines and applications: a review), IE. Proc. Electric Power Appl., 2001, 148, pp. 299-308. The magnetic field generated by such a Halbach array has the property that it is concentrated on one side and weakens to almost zero on the other side. Linear Halbach arrays are disclosed, for example, in WO 2015 / 086257 A1 and WO 2018 / 019594 A1, and Halbach cylindrical devices are disclosed in EP 3 224 055 B1.

[0159] According to one embodiment, steps b') and b'') of the method described herein for orienting sheet-like magnetic or magnetizable pigment particles independently include exposing a radiation-curable coating composition to a rotating magnetic assembly at an appropriate speed. Examples of rotating magnetic assemblies are assemblies comprising one or more disk-shaped rotating magnets or magnetic assemblies magnetized substantially along their diameter. Magnetic assemblies comprising rotating magnets or magnetic field generating devices are described in US 2007 / 0172261 A1. These rotating magnets or magnetic field generating devices produce radially symmetrical, time-varying magnetic fields, allowing biaxial orientation of pigment particles. These magnetic assemblies are driven by a shaft (or spindle) connected to an external motor. CN 102529326 B discloses examples of magnetic assemblies comprising rotating magnets that can be used to biaxially orient pigment particles. In a preferred embodiment, a suitable magnetic assembly is a shaftless, disk-shaped rotating magnetic assembly confined within a housing made of a non-magnetic, preferably non-conductive, material.And driven by one or more magnetic coils wound around the housing. Examples of such shaftless disc-shaped rotating magnetic assemblies are disclosed in WO 2015 / 082344 A1, WO 2016 / 026896 A1 and WO2018 / 141547 A1.

[0160] The following combination of multiple sets of steps is also described herein:

[0161] - a first set of steps including step b') and a second set of steps including step b''), both of which independently include the one-step magnetic orientation step described herein; and

[0162] - a first set of steps including step b') and a second set of steps including step b''), independently including the two-step magnetic orientation steps described herein, preferably the two-step magnetic orientation steps independently including a first orientation step to biaxially orient the sheet-like magnetic or magnetizable pigment particles, followed by a second orientation step to re-orient the sheet-like magnetic or magnetizable pigment particles described herein.

[0163] After or partially simultaneously, preferably partially simultaneously, the orientation of the sheet-like magnetic or magnetizable pigment particles described herein is independently fixed or frozen by curing (steps c' and c''). Therefore, it is noteworthy that the first and second coating compositions must have a first state, i.e., a liquid or paste state, in which the composition has not yet hardened and is sufficiently wet or soft, such that the sheet-like magnetic or magnetizable pigment particles dispersed in the composition can move, rotate, and orient freely when exposed to a magnetic field, and a second hardened (e.g., solid or solid state) state in which the sheet-like magnetic or magnetizable pigment particles are fixed or frozen in their respective positions and orientations.

[0164] Such first and second states are preferably provided by using some type of coating composition. For example, the components of the first and second radiation-curable coating compositions, other than the flake-like magnetic or magnetizable pigment particles, can take the form of ink or coating compositions, such as those used in security applications like banknote printing. The aforementioned first and second states can be provided by using materials that exhibit an increase in viscosity in response to stimuli such as temperature changes or exposure to electromagnetic radiation. That is, when the fluid binder material hardens or cures, it transforms into a second state, a hardened or solid state, in which the flake-like magnetic or magnetizable pigment particles are fixed in their current position and orientation and cannot move or rotate further within the binder material. As is known to those skilled in the art, the components contained in the ink or coating composition to be applied directly or indirectly to a substrate and the physical properties of the ink or coating composition must meet the requirements of the method for transferring the ink or coating composition. Therefore, the binder materials contained in the coating compositions described herein are generally selected from those known in the art.And it depends on the coating or printing method used to apply the ink or coating composition and the selected curing method.

[0165] The curing steps (step c') and c'')) described herein independently involve a chemical reaction, such as curing, which cannot be reversed by a simple temperature increase (e.g., up to 80°C) that may occur during typical use of secure documents. The terms “curing” or “curability” refer to a method of chemical reaction, crosslinking, or polymerization of at least one component of the applied coating composition, in which it is transformed into a polymer material having a molecular weight greater than that of the starting material. Preferably, curing results in the formation of a stable three-dimensional polymer network. Such curing is typically induced (steps c') and c'')) by (i) after the application of the composition (steps a') and a'')) and (ii) after or partially simultaneously with the application of an external stimulus to the composition after (steps b') and b'')) of the orientation of at least a portion of the sheet-like magnetic or magnetizable pigment particles. Advantageously, the curing steps (step c') and c'') of the first and second coatings (x20' and x20'') described herein are performed independently and simultaneously with the orientation (step b') and b'') of at least a portion of the sheet-like magnetic or magnetizable pigment particles (step c') and c'')). Radiation curing, particularly UV-Vis curing, advantageously results in a momentary increase in viscosity of the first and second radiation-curable coating compositions after exposure to radiation, thereby preventing any further movement of the pigment particles and thus preventing any information loss after the magnetic orientation step. Preferably, the curing steps (step c') and c'')) are performed independently by UV-Vis irradiation (i.e., UV-Vis light radiation curing) or by electron beam (i.e., electron beam radiation curing), more preferably by UV-Vis light irradiation, because UV-Vis curing advantageously allows for a very fast curing process and thus significantly reduces the preparation time of the OEL described herein, documents and articles containing the OEL, and documents.

[0166] Preferably, the first or second radiation-curable coating composition, and more preferably the first and second UV-Vis curable coating compositions, independently comprise one or more compounds selected from the group consisting of free radical curable compounds and cationic curable compounds. The compositions described herein may be mixed systems and comprise a mixture of one or more cationic curable compounds and one or more free radical curable compounds. Cationic curable compounds cure via a cationic mechanism, which typically involves activation by radiation with one or more photoinitiators that release cationic substances such as acids, which in turn initiate curing to cause monomers and / or oligomers to react and / or crosslink, thereby hardening the coating composition. Free radical curable compounds cure via a free radical mechanism.The free radical mechanism typically involves activation via radiation of one or more photoinitiators, thereby generating free radicals that in turn initiate polymerization to harden the coating composition. Different photoinitiators may be used depending on the monomer, oligomer, or prepolymer used to prepare the binder contained in the first and second radiation-curable coating compositions described herein. Suitable examples of free radical photoinitiators are known to those skilled in the art and include, but are not limited to, acetophenones, benzophenones, benzyl dimethyl ketals, α-amino ketones, α-hydroxy ketones, phosphine oxides and phosphine oxide derivatives, and mixtures of two or more thereof. Suitable examples of cationic photoinitiators are known to those skilled in the art and include, but are not limited to, onium salts such as organic iodonium salts (e.g., diaryliodonium salts), oxonium salts (e.g., triaryloxonium salts), and sulfonium salts (e.g., triarylsulfonium salts), and mixtures of two or more thereof. Other examples of available photoinitiators can be found in standard textbooks. To achieve effective curing as specified on pages 29 / 43 of the specification (CN 122422064 A), a sensitizer combined with one or more photoinitiators may advantageously be included. Typical examples of suitable photosensitizers include, but are not limited to, isopropylthioxanthone (ITX), 1-chloro-2-propoxy-thioxanthone (CPTX), 2-chloro-thioxanthone (CTX), and 2,4-diethyl-thioxanthone (DETX), as well as mixtures of two or more thereof. The photoinitiator included in the UV-Vis curable coating composition is preferably present in a total amount of about 0.1% by weight to about 20% by weight, more preferably about 1% by weight to about 15% by weight, based on the total weight of the first and second radiation-curable coating compositions, respectively.

[0167] The first and second radiation-curable coating compositions described herein may further independently comprise one or more additives, including but not limited to compounds and materials for adjusting the physical, rheological, and chemical parameters of the composition, such as viscosity (e.g., solvents and surfactants), consistency (e.g., antisettling agents, fillers, and plasticizers), foaming properties (e.g., defoamers), lubricity (waxes), UV reactivity and stability (photosensitizers and light stabilizers), and adhesion. The additives described herein may be present in the coating compositions in amounts and forms known in the art, including in the form of so-called nanomaterials, wherein at least one particle size is in the range of 1 to 1000 nm.

[0168] The first and second radiation-curable coating compositions described herein can be independently prepared by dispersing or mixing the sheet-like magnetic or magnetizable pigment particles described herein and one or more additives, when present, in the presence of the binder material described herein, thereby forming a liquid composition. When present, one or more photoinitiators may be added to the composition during the dispersion or mixing steps of all other components, or may be added at a later stage.That is, it is added after the formation of the liquid coating composition.

[0169] The method for generating OEL described herein includes a curing step c (steps c') and c'')) of the radiation-curable coating composition, which is partially simultaneous with or after step b (steps b') and / or b'')) and preferably partially simultaneous. The step of curing the coating composition allows the flake-like magnetic or magnetizable pigment particles to be fixed in their adopted positions and orientations in the desired pattern to form an OEL, thereby transforming the radiation-curable coating composition into a second state. However, the time from the end of the orientation step b (steps b') and / or b'')) to the start of the curing step c (steps c') and / or c'')) is preferably relatively short to avoid any loss of orientation and information loss. Typically, the time between the end of step b (steps b') and / or b'')) and the start of step c (steps c') and c'')) is less than 1 minute, preferably less than 20 seconds, and more preferably less than 5 seconds. Particularly preferably, there is substantially no time interval between the end of orientation step b) (step b') and / or b'')) and the start of curing step c) (step c') and / or c'')), i.e., step c) is performed immediately after step b) or step c) begins while step b) is still in progress (partially simultaneous). The term "partially simultaneous" means that the two steps are performed partially simultaneously, i.e., the time for each step partially overlaps. In the context described herein, when curing is performed partially simultaneously with step c), it must be understood that curing becomes effective after orientation, such that the flake-like magnetic or magnetizable pigment particles are oriented before the OEL is fully or partially cured. As mentioned herein, the curing steps (step c) (step c') and c'')) can be performed by different means or methods depending on the binder material contained in the coating composition, which also contains flake-like magnetic or magnetizable pigment particles.

[0170] The curing step can generally be any step that increases the viscosity of the radiation-curable coating composition to form a substantially solid material adhered to the substrate. The curing step may involve a physical process (i.e., physical drying) based on the evaporation of volatile components such as solvents and / or water evaporation. In this document, hot air, infrared radiation, or a combination of hot air and infrared radiation may be used. Alternatively, the curing step may include a chemical reaction, such as the curing, polymerization, or crosslinking of binders and optional initiator compounds and / or optional crosslinking compounds contained in the radiation-curable coating composition. Such a chemical reaction may be initiated by thermal or IR radiation as described above for physical curing processes, but may preferably include chemical reactions initiated by radiation mechanisms, including but not limited to ultraviolet-visible radiation curing (hereinafter referred to as UV-Vis curing) and electron beam radiation curing (electron beam curing); oxidative polymerization (oxidative networking,Typically induced by the combined action of oxygen and preferably one or more catalysts selected from the group consisting of cobalt-containing catalysts, vanadium-containing catalysts, zirconium-containing catalysts, bismuth-containing catalysts, and manganese-containing catalysts; crosslinking reactions or any combination thereof.

[0171] Radiation curing is particularly preferred, and UV-Vis radiation curing is even more preferred, as these techniques advantageously result in a very fast curing process and thus significantly reduce the preparation time of any article containing the OEL described herein. Furthermore, radiation curing has the advantage of producing an almost instantaneous increase in viscosity of the coating composition upon exposure to curing radiation, thereby minimizing any further movement of the particles. Thus, any orientation loss after the magnetic orientation step can be substantially avoided. Particularly preferred is radiation curing by photopolymerization under the influence of photochemical light with a wavelength component in the UV or blue portion of the electromagnetic spectrum (typically 200 nm to 650 nm; more preferably 200 nm to 420 nm). Suitable curing units (x50) for curing steps (step c') and c'') may include high-power light-emitting diode (LED) lamps or arc discharge lamps, such as medium-pressure mercury arc lamps (MPMA) or metal vapor arc lamps, as photochemical radiation sources. In contrast to medium-pressure mercury lamps, which have emission bands in the UV-A, UV-B, and UV-C regions of the electromagnetic spectrum, UV-LED lamps emit radiation in the UV-A region and / or the visible (Vis) region, for example, in the range from about 350 nm to about 470 nm. Furthermore, current UV-LED and Vis-LED lamps emit quasi-monochromatic radiation, i.e., they emit only at one wavelength, such as 365 nm, 385 nm, 395 nm, 405 nm, or 450 nm. Preferably, at least one of steps c') and c'') described herein is performed by exposing the first coating (x20') and the second coating (x20'') to UV light, preferably to one or more wavelengths between about 355 nm and about 415 nm, more preferably by exposing them to UV light of 365 nm and / or 385 nm and / or 395 nm emitted from the LED curing unit (x50), and more preferably steps c') and c'').

[0172] Alternative methods for producing the OEL described herein are also described herein, wherein the first and second coatings are applied to the same or opposite sides of the substrate, and wherein the first and second magnetic patterns are symmetrical with respect to a mirror plane parallel to the substrate (x10), and wherein the OEL is obtained by using different magnetic components in steps b') and b''), wherein when the first and second coatings are applied to the same side,Two magnetic components are located on the uncoated side. An OEL comprising first and second coatings (x20' and x20'') on the same side of the substrate (x10) can be produced by exposing the first and second radiation-curable coating compositions to magnetic components (preferably located on the uncoated side):

[0173] - For an OEL in which both the first and second patterns exhibit dynamic movement when the OEL is tilted, the dynamic movement being bright reflective horizontal bars moving in the vertical direction (up / down) when the OEL is tilted about a horizontal axis, a) a magnetic component comprising a dipole magnet having a magnetic axis oriented substantially parallel to the substrate, as shown in FIG8, can be used in one step, and b) those magnetic components disclosed in FIG5-9 of WO 2014 / 198905 A2, and particularly FIG5c, 6c, and 7d of WO 2014 / 198905 A2, can be used in another step;

[0174] -For an OEL in which both the first and second figures exhibit dynamic movement when the OEL is tilted, the dynamic movement of the OEL being a bright reflective vertical bar that moves in the horizontal (left / right) direction when the OEL is tilted about a horizontal axis,

[0175] a) those disclosed in WO 2020 / 160993 A1 (e.g. those shown in Figures 2-5 of WO 2020 / 160993 A1) and the magnetic components described herein may be used in one step, and b) except that in Figures 2 and 4 of WO 2020 / 160993 A1 the value of angle β is changed to β'=180°-β, in Figure 3 the value of angle α is changed to α'=-α, and in Figure 5 the magnetization reversal (N->S, and S->N) of magnets 531-a1, 531-a2, 531-b1 and 531-b2, the same magnetic components used in the first step may be used in another step, except that the magnetization reversal (N->S, and S->N) of magnets 531-a1, 531-a2, 531-b1 and 531-b2 is reversed in another step;

[0176] - For an OEL in which both the first and second figures exhibit dynamic movement when the OEL is tilted, the dynamic movement being a ring-shaped body whose size changes as the OEL is tilted; Specification 31 / 43 pages 34 CN 122422064 A

[0177] a) those disclosed in WO 2017 / 064052 A1 (e.g., those shown in Figures 1-4 of WO 2017 / 064052 A1) and the magnetic components described herein may be used in one step, and

[0178] b) except for reversing the magnetization (N->S, and S->N) of the magnet (x30) in Figures 1-4 of WO 2017 / 064052 A1,The same magnetic components used in the first step may be used in another step;

[0179] - For an OEL in which both the first and second shapes exhibit dynamic movement when the OEL is tilted, the dynamic movement being a toroidal body whose size changes as the OEL is tilted;

[0180] a) The magnetic components disclosed in WO 2017 / 080698 A1 (e.g., those shown in Figures 1-12 of WO 2017 / 080698 A1) and described herein may be used in one step, and b) Except for reversing the magnetization of the magnets (x31 and x32) (N->S, and S->N) in Figures 1-12 of WO 2017 / 080698 A1, the same magnetic components used in the first step may be used in another step;

[0181] - For an OEL in which both the first and second shapes exhibit dynamic movement when the OEL is tilted, the dynamic movement being a toroidal body whose size changes as the OEL is tilted;

[0182] a) In one step, those disclosed in WO 2017 / 148789 A1 (e.g., those shown in Figures 1-14 of WO 2017 / 148789 A1) and the magnetic components described herein may be used, and

[0183] b) In another step, except for reversing the magnetization of the magnets (x31 and x32) (N->S, and S->N) as shown in Figures 1-14 of WO 2017 / 148789 A1, the same magnetic components used in the first step may be used;

[0184] - For an OEL in which both the first and second figures exhibit dynamic movement when the OEL is tilted, the dynamic movement being a pattern of bright and dark areas moving when the OEL is tilted,

[0185] a) In one step, those disclosed in WO 2021 / 083809 A1 (e.g., those shown in Figures 1-14 of WO 2017 / 148789 A1) may be used, and

[0185] a) In one step, those disclosed in WO 2021 / 083809 A1 (e.g., those shown in Figures 1-14 of WO 2017 / 148789 A1) may be used, and [0186 ... the same magnetic components disclosed in WO 2021 / 083809 A1 may be used, and

[0186] a) In one step, the same magnetic components disclosed in WO 2021 / 083809 A1 (e.g., those shown in Figures 1-14 of WO 2017 The magnetic components described herein, and

[0186] b) except that, in Figures 6-8 of WO 2021 / 083809 A1, at least one dipole magnet (x41) is replaced with those magnetic components disclosed in Figures 5-9 of WO 2014 / 198905 A2 (particularly Figures 5c, 6c and 7d of WO 2014 / 198905 A2) and the magnetization of the magnet (x31) is reversed (N->S, and S->N), the same magnetic components used in the first step may be used in another step;

[0187] - For an OEL in which both the first and second figures exhibit dynamic movement when the OEL is tilted, the dynamic movement being a pattern of bright and dark areas moving when the OEL is tilted.

[0188] a) In one step, the magnetic components disclosed in WO 2021 / 083808 A1 (e.g., those shown in Figures 5-7 of WO 2021 / 083808 A1) and described herein may be used, and

[0189] b) In addition to replacing at least one dipole magnet (x41) with those magnetic components disclosed in Figures 5-9 of WO 2014 / 198905 A2 (particularly Figures 5c, 6c and 7d of WO 2014 / 198905 A2) and reversing the magnetization of the magnet (x31) (N->S, and S->N), the same magnetic components used in the first step may be used in another step.

[0190] Prior to curing step c'), the first coating (x20') may undergo customization to produce an OEL that further exhibits more than one mark, wherein the customization step is performed after the orientation step b') and before the curing step c'). Prior to curing step c''), the second coating (x20'') may undergo customization to produce an OEL that further exhibits more than one mark, wherein the customization step is performed after the orientation step b'') and before the curing step c''). Preferably, prior to curing steps c') and c''), the first coating (x20') and the second coating (x20'') may be customized independently to produce an OEL that further exhibits more than one mark, wherein the customization step is performed after the orientation steps b') and b'') and before the curing steps c') and c''), and wherein the mark thus obtained extends across both the first and second figures. The customization step is preferably performed by applying a liquid coating composition on top of the coating while it is still wet (wet-to-wet method), said application being performed by a non-contact fluid micro-dispensing method disclosed in WO 2021 / 259527 A1.

[0191] The present invention provides a method for producing the OEL described herein on a substrate (x10) described herein. The substrate described herein is preferably selected from the group consisting of: paper or other fibrous materials such as cellulose (including woven and nonwoven fibrous materials), paper-containing materials, glass, metals, ceramics, plastics and polymers, metallized plastics or polymers, at least partially opaque plastics or polymers, composite materials, and mixtures or combinations thereof. Typical paper, paper-like, or other fibrous materials are made of various fibers, including but not limited to, abaca, cotton, flax, wood pulp, and blends thereof. As is known to those skilled in the art, cotton and cotton / flax blends are preferably used for banknotes.Wood pulp is typically used for security documents other than banknotes. Typical examples of plastics and polymers include polyolefins such as polyethylene (PE) and polypropylene (PP), including biaxially oriented polypropylene (BOPP); polyamides such as polyethylene terephthalate (PET), polybutane terephthalate (PBT), and polyethylene 2,6-naphthelate (PEN); and polyvinyl chloride (PVC). Spunbond olefin fibers, such as those sold under the trademark Tyvek®, can also be used as substrates. Typical examples of metallized plastics or polymers include the aforementioned plastic or polymer materials on which metals are deposited continuously or discontinuously on their surfaces. Typical examples of metals include, but are not limited to, aluminum (Al), chromium (Cr), copper (Cu), gold (Au), silver (Ag), their alloys, and combinations of two or more of the aforementioned metals. Metallization of the aforementioned plastic or polymer materials can be accomplished by electrodeposition, high-vacuum coating, or sputtering. Opaque polymers have been developed to mimic the appearance and some properties of conventional paper-based substrates used for secure documents and include transparent polymer substrates, which are typically surface-treated with an opaque layer on one or both sides to form an opaque polymer-based substrate. Typical examples of composite materials include, but are not limited to, paper and at least one plastic or polymeric material such as those described above, as well as multilayer structures or laminates incorporating paper-like or fibrous materials such as the plastic and / or polymeric fibers described above. Of course, the substrate may further contain additives known to those skilled in the art, such as fillers, sizing agents, brighteners, processing aids, reinforcing or humectant agents, etc. When the OEL produced according to the invention is used for decorative or cosmetic purposes, including, for example, nail polish, the OEL can be produced on other types of substrates including animal or human nails, artificial nails, or other parts.

[0192] According to one embodiment, the substrate (x10) described herein is a transparent substrate, preferably selected from the group consisting of: transparent polyolefins (such as polyethylene (PE) and polypropylene (PP) including biaxially oriented polypropylene (BOPP)), transparent polyamides, transparent polyesters (such as polyethylene terephthalate (PET), polybutanediol terephthalate (PBT), polyethylene 2,6-naphthalenedicarboxylate (PEN), and transparent polyvinyl chloride (PVC), more preferably biaxially oriented polypropylene; or a partially opaque substrate, particularly a transparent polymer that is at least partially opaque.It is preferably selected from the group consisting of: transparent polyolefins (such as polyethylene (PE) and polypropylene (PP) including biaxially oriented polypropylene (BOPP)), transparent polyamides, transparent polyesters (such as polyethylene terephthalate (PET), polybutanediol terephthalate (PBT), polyethylene 2,6-naphthalenedicarboxylate (PEN), and transparent polyvinyl chloride (PVC), more preferably biaxially oriented polypropylene. According to one embodiment, the OEL described herein is present on banknotes and on those transparent substrates as described herein, and preferably in the form of a window or foil, or on those at least partially opaque substrates as described herein, preferably in the form of a non-opaque area, in the form of a window or foil.

[0193] The substrate (x10) described herein may be in the form of web, sheet, thread reel, film reel, labels of the roll, or label material, preferably in sheet form.

[0194] If the OEL generated according to the present invention is on a secure document, and for the purpose of further enhancing the security level and resistance to counterfeiting and illegal copying of the secure document (see page 33 / 43 of the specification, CN 122422064 A), the substrate may contain printed, coated, or laser-marked or laser-perforated markings, watermarks, security threads, fibers, planchettes, luminescent compounds, windows, foils, labels, and combinations thereof. Also for the purpose of further enhancing the security level and resistance to counterfeiting and illegal copying of the secure document, the substrate may contain one or more marking substances or tracers and / or machine-readable substances. According to one embodiment, the substrate (x10) comprises a printed pattern, preferably an offset-printed pattern, wherein at least one of the radiation-curable coating compositions of steps a') and a'') is at least partially applied on top of the printed pattern, and the method described herein includes the step of printing ink on the substrate (x10) described herein, wherein, as appropriate, the step occurs prior to steps a') and a'').

[0195] If desired, a primer layer may be applied to the substrate (x10) before step a') and / or before step a''). This may improve the quality of the OEL described herein or promote adhesion. Examples of such primer layers can be found in WO 2010 / 058026 A2.

[0196] For the purpose of improving durability by increasing stain resistance or chemical resistance and cleanliness, thereby increasing the cycle life of articles, security documents, or decorative elements or objects containing an OEL obtained by the methods described herein, or for the purpose of altering their aesthetic appearance (e.g., optical gloss), more than one protective layer may be applied on top of the OEL. When present,One or more protective layers are typically made of protective varnish. These may be transparent, slightly tinted, or colored, and may be more or less glossy. The protective varnish may be a radiation-curing composition, a heat-drying composition, or any combination thereof. Preferably, one or more protective layers are radiation-curing compositions, more preferably UV-Vis curing compositions. The protective layers are typically applied after the OEL is formed.

[0197] The methods described herein may further include the step of embossing the OEL described herein using, for example, embossing dyes or gravure printing plates, as disclosed in WO 2012 / 025206 A2 and WO 2019 / 233624 A1.

[0198] The OEL described herein can be used in combination with holograms, microlenses, and / or micromirrors as described in WO 2020 / 244805 A1, EP 3 254 863 A1, US 2008 / 0160226, US 2005 / 0180020, and EP 2 284 017 A1, which are applied at locations spaced apart from or at least partially applied on top of or below the OEL.

[0199] The invention further provides an optical effect layer (OEL) produced by the method according to the invention.

[0200] Alternatively, in another embodiment, an adhesive layer may be present. Thus, the adhesive layer can be applied after the curing step of the last set of steps described herein has been completed. Such articles can be attached to all kinds of documents or other articles or items without printing or other processes involving machinery and a considerable amount of work. Alternatively, the substrate comprising the OEL described herein may be in the form of a transfer foil, which may be applied to a document or article in a separate transfer step. For this purpose, the substrate is provided with a release coating, on which the OEL is produced, as described herein.

[0201] This document also describes substrates comprising more than one, i.e., two, three, four, etc. (x10). Each of the OELs obtained by the methods described herein independently comprises first and second patterns as described herein in the form of first and second coatings (x20', x20''). The method described herein for generating more than one OEL on a substrate (x10) may include: a first set of steps a'), b'), and c') for generating a first pattern of a first OEL; a second set of steps a''), b''), and c'') for generating a second pattern of the first OEL; a third set of steps a'''), b'''), and c''') for generating a first pattern of a second OEL; and a fourth set of steps a''''), b''''), and c'''') for generating a second pattern of the second OEL. Alternatively,The method described herein for generating more than one OEL on a substrate (x10) may include: a first set of steps a'), b'), and c') for generating a first graphic of a first OEL (page 34 / 43 of specification 37 CN 122422064 A); a second set of steps a''), b''), and c'') for generating a first graphic of a second OEL; a third set of steps a'''), b'''), and c''') for generating a second graphic of the first OEL; and a fourth set of steps a''''), b''''), and c'''') for generating a second graphic of the second OEL.

[0202] This document also describes articles comprising OELs generated according to the invention, particularly security documents, decorative elements, or objects. Such articles, particularly security documents, decorative elements, or objects, may comprise more than one (e.g., two, three, etc.) OELs generated according to the invention.

[0203] As described above, OELs generated according to the invention can be used for decorative purposes as well as for protecting and authenticating security documents.

[0204] Typical examples of decorative elements or objects include, but are not limited to, luxury goods, cosmetic packaging, vehicle parts, electronic / electrical appliances, furniture, and nail products.

[0205] Secure documents include, but are not limited to, documents of value and goods of value. Typical examples of documents of value include, but are not limited to, banknotes, contracts, bills, checks, vouchers, stamp duty stamps and tax labels, and agreements, as well as identity documents such as passports, ID cards, visas, driver's licenses, bank cards, credit cards, transaction cards, passes or cards, admission tickets, public transport tickets, or titles, preferably banknotes, identity documents, grants of rights, driver's licenses, and credit cards. The term "goods of value" refers to packaging materials, particularly those used for cosmetics, nutritional products, pharmaceutical products, alcoholic beverages, tobacco products, beverages or food, electrical / electronic products, textiles, or jewelry, i.e., articles that should be protected against counterfeiting and / or illegal reproduction in order to secure the contents of the packaging, such as genuine medicines. Examples of these packaging materials include, but are not limited to, labels such as certified brand labels, tamper-evident labels, and seals. It should be noted that the disclosed substrates, valuable documents, and valuable goods are given for illustrative purposes only and do not limit the scope of the invention.

[0206] Alternatively, the OEL can be produced on an auxiliary substrate, such as, for example, a security thread, security strip, foil, decal, or window, and thus transferred to the security document in a separate step.

[0207] Without departing from the spirit of the invention,Those skilled in the art can conceive of several modifications to the specific embodiments described above. These modifications are included in this invention.

[0208] Furthermore, all documents mentioned throughout this specification are incorporated herein by reference in their entirety, as fully set forth herein.

[0209] Examples

[0210] The invention will now be described in more detail with reference to non-limiting examples. The following examples provide further details of the method according to the invention and suitable magnetic components for producing optical effect layers (OELs).

[0211] OELs obtained by the method of Examples E1-E4 were prepared on a laboratory apparatus according to a method comprising two sets of steps, wherein both orientation steps b') and b'') are shown in FIG5-1 to simulate an industrial method comprising two sets of two-step magnetic orientation steps as shown in FIG5-2. The precise registration of the first and second patterns (i.e., the first and second cured coatings (x20' and x20'') is ensured by using a screen containing guide marks in addition to the pattern to be printed.

[0212] Examples E1-E4 were prepared independently using the first and second UV-curable screen printing inks in Table 1, wherein the first ink was applied to a first side of a transparent substrate (x10) (polymer BOPP substrate, Guardian™ from CCL) during step a') to form a first coating (x20'), and the second UV-curable screen printing ink was applied to a second side of the substrate (x10) during step a''), i.e., the side without the first coating (x20').

[0213] A first UV-curable screen printing ink (step a') is applied to a first side of the substrate (x10) by manual screen printing using a first T90 screen (x40') to form a first coating (x20') with a thickness of about 20 μm and having a shape as shown in Table 2, page 35 / 43 of the specification, 38 CN 122422064 A.

[0214] A second UV-curable screen printing ink (step a'') is applied to a second side of the substrate (10) and precisely registered with the first coating (x20') applied in step a') by manual screen printing using a second T90 screen (x40'') to form a second coating (x20'') with a thickness of about 20 μm and having a shape as shown in Table 2.

[0215] Two-step orientation steps for the two patterns on opposite sides of the substrate (Fig. 5-1)

[0216] The substrate (510) carrying the coating (520') is moved over the static magnetic assembly (530'-a) (see gray arrow) (step b'-1) and then placed over the magnetic assembly (530'-b) (step b'-2). Then, simultaneously with the orientation step b'-2) (i.e., while the substrate (510) carrying the first coating (520') is still in the magnetic field of the magnetic assembly (530'-b),The magnetic orientation pattern of the thus obtained flake-like magnetic pigment particles is fixed by exposing the layer containing the pigment particles to a first UV-LED lamp (550') (model FireFlex 50×75mm, 395nm, 8W / cm2) from Phoseon for approximately 1.5 seconds for UV curing (step c'). The substrate (510) is flipped / rotated, and a second UV-curable screen-printed ink (step a'') is applied to the opposite side of the first coating (520') to form a second coating (520'') precisely registered with the first coating (520''). The substrate (510) bearing the first and second coatings (520' and 520'') is moved over the static magnetic assembly (530''-a) (see gray arrow) (step b''-1) with the first coating (520') facing the static magnetic assembly (530''-a) and then placed over the magnetic assembly (530''-b) (step b''-2) with the first coating (520') facing the magnetic assembly (530''-b). Then, simultaneously with the orientation step b''-2) (i.e., while the substrate (510) carrying the first and second coatings (520' and 520'') is still in the magnetic field of the magnetic component (530''-b), the magnetic orientation pattern of the thus obtained flake-shaped magnetic pigment particles is fixed by exposing the layer containing the pigment particles to UV curing for about 1.5 seconds using a second UV-LED lamp (550'') from Phoseon (model FireFlex 50×75mm, 395nm, 8W / cm2) for about 1.5 seconds.

[0217] Table 1 Specification 36 / 43 pages 39 CN 122422064 A

[0218]

[0219] ( ) Green to blue color-changing magnetic pigment particles (flake-shaped pigment particles) in the shape of flakes with a diameter d50 of about 11μm and a thickness of about 1μm.

[0220] ( ) flake-shaped magenta to blue color-changing magnetic pigment particles (flake-shaped pigment particles) with a diameter d50 of about 11 μm and a thickness of about 1 μm.

[0221] ( ) flake-shaped gold to green color-changing magnetic pigment particles (flake-shaped pigment particles) with a diameter d50 of about 11 μm and a thickness of about 1 μm.

[0222] Magnetic assembly of FIG7

[0223] A magnetic assembly (730) for biaxially oriented pigment particles according to the method of the invention is disclosed in FIG3A of WO 2021 / 239607 A1. When used in the first step b-1 of FIG6, the magnetic assembly (730) comprises (630-a) and when used in the second step b-2 of FIG6, the magnetic assembly (730) comprises (630-c).

[0224] The magnetic assembly (730) comprises a) a first group (S1),It comprises a first rod-shaped dipole magnet (731-a) and two second rod-shaped dipole magnets (732-a and 732-d); a second group (S2) comprising a first rod-shaped dipole magnet (731-b) and two second rod-shaped dipole magnets (732-b and 732-e); a third group (S3) comprising a first rod-shaped dipole magnet (731-c) and two second rod-shaped dipole magnets (732-c and 732-f); and b) a first pair (P1) of third rod-shaped dipole magnets (733-a and 733-b); and a second pair (P2) of third rod-shaped dipole magnets (733-c and 733-f).

[0225] The uppermost surfaces of the first rod-shaped dipole magnets (731-a, 731-b and 731-c) of the first group, the second group and the third group (S1, S2, S3), the second rod-shaped dipole magnets (732-a to 732-f) of the first group, the second group and the third group (S1, S2, S3), the first pair of specification pages 37 / 43 40 CN 122422064 A, and the third rod-shaped dipole magnets (733-a to 733-d) of the second pair (P1 and P2) are flush with each other.

[0226] The third rod-shaped dipole magnet (733-a) of the first pair (P1) is aligned with the second rod-shaped dipole magnet (732-a) of the first group (S1), the second rod-shaped dipole magnet (732-b) of the second group (S2), the third rod-shaped dipole magnet (733-c) of the second pair (P2), and the second rod-shaped dipole magnet (732-c) of the third group (S3), thereby forming a line. The third rod-shaped dipole magnet (733-b) is aligned with the second rod-shaped dipole magnet (732-d) of the first group (S1), the second rod-shaped dipole magnet (732-e) of the second group (S2), the third rod-shaped dipole magnet (733-d) of the second pair (P2), and the second rod-shaped dipole magnet (732-f) of the third group (S3), thereby forming a line. For each line described herein,The third rod-shaped dipole magnets (733-a, 733-b, 733-c and 733-d) and the second rod-shaped dipole magnets (732-a to 732-f) are spaced apart by a third distance (d2) of 2 mm. The first rod-shaped dipole magnets (731-a) of the first group (S1), the first rod-shaped dipole magnets (731-b) of the second group (S2), and the first rod-shaped dipole magnets (731-c) of the third group (S3) are spaced apart by a distance (d3) of 24 mm.

[0227] The first rod-shaped dipole magnets (731-a, 731-b and 731-c) of the first, second and third groups (S1, S2, S3) have the following dimensions: a first length (L1) of 60 mm, a first width (L2) of 40 mm and a first thickness (L3) of 5 mm. Each of the second rod-shaped dipole magnets (732-a to 732-f) in the first, second, and third groups (S1, S2, S3) has the following dimensions: a second length of 40 mm (L4), a second width of 10 mm (L5), and a second thickness of 10 mm (L6). Each of the third rod-shaped dipole magnets (733-a to 733-d) in the first and second pairs (P1, P2) has the following dimensions: a third length of 20 mm (L7), a third width of 10 mm (L8), and a third thickness of 10 mm (L9).

[0228] The first rod-shaped dipole magnet (731-a) of the first group (S1) and the second rod-shaped dipole magnet (732-a and 732-d) of the first group (S1) are aligned to form a column; and the first rod-shaped dipole magnet (731-b) of the second group (S2) and the second rod-shaped dipole magnet (732-b and 732-e) of the second group (S2) are aligned to form a column; and the first rod-shaped dipole magnet (731-c) of the third group (S3) and the second rod-shaped dipole magnet (732-c and 732-f) of the third group (S3) are aligned to form a column. For each group (S1, S2, S3) and each column described herein, the first rod-shaped dipole magnets (731-a, 731-b, and 731-c) and the two second rod-shaped dipole magnets (732-a and 732-d; 732-b and 732-e; and 732-c and 732-f, respectively) are spaced apart by a second distance (d1) of 2 mm.

[0229] The magnetic axis orientation of the first rod-shaped dipole magnets (731-a, 731-b, and 731-c) in the first, second, and third groups (S1, S2, S3) is substantially parallel to the substrate (710), wherein the magnetic direction of the first rod-shaped dipole magnet (731-a) in the first group (S1) is opposite to the magnetic direction of the first rod-shaped dipole magnet (731-b) in the second group (S2).Furthermore, the magnetic direction of the first rod-shaped dipole magnet (731-b) in the second group (S2) is opposite to that of the first rod-shaped dipole magnet (731-c) in the third group (S3). The first rod-shaped dipole magnet (731-a) in the first group (S1) and the first rod-shaped dipole magnet (731-b) in the second group (S2), as well as the first rod-shaped dipole magnet (731-b) in the second group (S2) and the first rod-shaped dipole magnet (731-c) in the third group (S3), are spaced apart by a first distance (d3) of 24 mm (corresponding to the sum of the third length (L7) and the two third distances (d2)).

[0230] The magnetic axis orientation of the two second rod-shaped dipole magnets (732-a to 732-f) in the first, second, and third groups (S1, S2, S3) is substantially perpendicular to the surface of the substrate (710). The south pole of the second rod-shaped dipole magnet (732-a) in the first group (S1), the south pole of the second rod-shaped dipole magnet (732-e) in the second group (S2), and the south pole of the second rod-shaped dipole magnet (732-c) in the third group (S3) point towards the substrate (710). The north pole of the second rod-shaped dipole magnet (732-d) in the first group (S1), the north pole of the second rod-shaped dipole magnet (732-b) in the second group (S2), and the north pole of the second rod-shaped dipole magnet (732-f) in the third group (S3) point towards the substrate (710). The north pole of the first rod-shaped dipole magnet (731-a) in the first group (S1) points towards the second rod-shaped dipole magnet (732-d) in the first group (S1); the north pole of the second rod-shaped dipole magnet (731-b) in the second group (S2) points towards the first rod-shaped dipole magnet (732-b) in the second group (S2); and the north pole of the first rod-shaped dipole magnet (731-c) in the third group (S3) points towards the second rod-shaped dipole magnet (732-f) in the third group (S3). The south pole of the third rod-shaped dipole magnet (733-a) in the first pair (P1) points towards the north pole of the second rod-shaped dipole magnet (732-f). (See page 41 of the manual, page 38 / 43, CN 122422064 A) The south pole of the second rod-shaped dipole magnet (732-a) in the first pair (S1) points towards the substrate (710); the south pole of the south pole of the third rod-shaped dipole magnet (733-d) in the second pair (P1) points towards the second rod-shaped dipole magnet (732-e) in the second pair (S2), and the south pole of the second rod-shaped dipole magnet (732-e) points towards the substrate (710); the north pole of the north pole of the third rod-shaped dipole magnet (733-b) in the first pair (P1) points towards the second rod-shaped dipole magnet (732-d) in the first pair (S1), and the north pole of the second rod-shaped dipole magnet (732-d) points towards the substrate (710); and the north pole of the third rod-shaped dipole magnet (733-c) in the second pair (P2) points towards the second rod-shaped dipole magnet (732-b) in the second pair (S2).The north pole of the second rod-shaped dipole magnet (732-b) points to the substrate (710).

[0231] The first rod-shaped dipole magnets (731-a, 731-b and 731-c) of the first, second and third groups (S1, S2, S3) and the second rod-shaped dipole magnets (732-a to 732-f) of the first, second and third groups (S1, S2, S3) are made of NdFeB N42; the third rod-shaped dipole magnets (733-a, 733-b, 733-c and 733-d) of the first pair and the second pair (P1, P2) are made of NdFeB N48. All magnets (731-a to 731-c, 732-a to 732-f, and 733-a to 733-d) are embedded in a non-magnetic support substrate (not shown) made of POM with the following dimensions: 200 mm × 120 mm × 12 mm.

[0232] Magnetic assembly of FIG8

[0233] The magnetic assembly (830) comprises a rod-shaped dipole magnet (830-1) and a retaining box (870). The rod-shaped dipole magnet (830-1) has a length and width of about 30 mm and a thickness of about 8.5 mm. The north-south magnetic axis of the rod-shaped dipole magnet (830-1) is parallel to the surface of the substrate (810), parallel to its length (L1), and parallel to the machine feed direction (shown by the arrow in FIG8). The rod-shaped dipole magnet (830-b1) is made of NdFeB BMnPi 80 / 48.

[0234] The retaining box (870) is made of a hollow top and bottom cover with curved surfaces. The hollow top has a length of about 40 mm, a width of about 40 mm, and a thickness of about 15.1 mm, and is made of PPS. The bottom cover has a length of about 35 mm, a width of about 35 mm, and a thickness of about 3 mm, and is made of POM. The curved surfaces are adapted to match the surface of a rotating magnetic cylinder of an industrial printing press. The hollow top is adapted to receive a rod-shaped dipole magnet (830-1).

[0235] The distance (h) between the top surface of the rod-shaped dipole magnet (830-1) and the bottom surface of the substrate (810) is about 3.35 mm.

[0236] Magnetic assembly of FIG9

[0237] The magnetic assembly (930) comprises a first disk-shaped dipole magnet (930-1), a second disk-shaped dipole magnet (930-2), a disk-shaped pole piece (960-1), a square wedge (980-1), and a retaining box (970).

[0238] The retaining box (970) is made of a hollow top and bottom cover with curved surfaces. The hollow top has a length and width of about 40 mm and a thickness of about 15.1 mm, and is made of PPS. The bottom cover has a length and width of about 35 mm and a thickness of about 3 mm.And it is made of POM.

[0239] The first disk-shaped dipole magnet (930-1) has a diameter of about 6 mm and a thickness of about 2 mm. The north-south magnetic axis of the disk-shaped dipole magnet (930-1) is perpendicular to the surface of the substrate (910) and perpendicular to its diameter, wherein its north pole points to the substrate (910). The disk-shaped dipole magnet (930-1) is made of NdFeB N45.

[0240] The second disk-shaped dipole magnet (930-2) has a diameter of about 10 mm and a thickness of about 1 mm L4. The north-south magnetic axis of the second disk-shaped dipole magnet (930-2) is perpendicular to the surface of the substrate (910) and perpendicular to its diameter, wherein its north pole points to the substrate (910). The disk-shaped dipole magnet (930-2) is made of NdFeB N35.

[0241] The disc-shaped electrode (960-1) has a diameter of approximately 30 mm and a thickness of approximately 2 mm. The disc-shaped electrode (960-1) is made of 140HV steel.

[0242] The square wedge (980-1) has a side length of approximately 29.9 mm and a thickness of approximately 6 mm. The square wedge (980-1) is made of polyethylene. Instruction manual, pages 39 / 43, CN 122422064 A

[0243] : A first disc-shaped dipole magnet (930-1) is disposed on top of a second disc-shaped dipole magnet (930-2) and in direct contact with the second disc-shaped dipole magnet (930-2). The second disc-shaped dipole magnet (930-2) is disposed on top of a disc-shaped pole piece (960-1) and in direct contact with the disc-shaped pole piece (960-1). The disc-shaped pole piece (960-1) is disposed on top of a square wedge (980-1) and in direct contact with the square wedge (980-1). The first disc-shaped dipole magnet (930-1), the second disc-shaped dipole magnet (930-2), the disc-shaped pole piece (960-1), and the square wedge (980-1) are centrally aligned.

[0244] The distance (h) between the top surface of the first disc-shaped dipole magnet (930-1) and the bottom surface of the substrate (910) is approximately 0.34 mm.

[0245] Table 2

[0246]

[0247] The OEL having a hot air balloon shape (see E1-E2), i.e., the combination of the first and second graphics shown in Table 2, has the following dimensions: a height of approximately 20 mm and a length of approximately 18 mm.

[0248] The OEL having an hourglass shape (see E3-E4), i.e., the combination of the first and second graphics shown in Table 2, has the following dimensions: a length of approximately 20 mm and a height of approximately 20 mm.

[0249] The claimed method allows the production of OELs comprising the first and second graphics described herein, which are perfectly registered not only in terms of the printed first and second graphics but also in terms of the effects derived from the first and second magnetic patterns, wherein their effects are achieved over the entire surface of the OEL.The OEL can be easily identified by the average person. The effect includes an image at a first viewing angle (e.g., 0°), the effect originating from the first and second magnetic patterns and including a continuous image extending from the first pattern to the second pattern, wherein the effect splits when tilted and recombines to form the same effect when tilted back to the first viewing angle, i.e., at viewing angles different from the first viewing angle, such as -45° and +45°; or in other words, the common visible pattern is observed by the average person due to the absence of any splitting of the OEL at a first viewing angle, and the striking effect is obtained by the dynamic splitting and recombination at tilt.

[0250] Since the common visible pattern at a 0° viewing angle appears as a single bar, E1 and E2 exhibit striking effects that are easily identified by the average person, wherein when the OEL is tilted, the bar splits into two bars, wherein when tilted to a 0° viewing angle, the two bars recombine to form a single bar. E2 further exhibits a striking effect obtained by two different colors of the first and second patterns, one being a color change from green to blue and the other being a color change from magenta to blue.

[0251] E3 and E4 exhibit a striking effect easily verifiable by the average person, as the commonly visible pattern at a 0° viewing angle presents a single double ring, wherein when the OEL is tilted at -45° or +45°, the ring splits into circular segments, and when tilted to a 0° viewing angle, the circular segments recombine to form a single double ring. E4 further exhibits a striking effect obtained from two different colors of the first and second patterns, one a color change from green to blue, and the other a color change from magenta to blue.

[0252] OELs E1-E4 obtained by the claimed method are highly suitable as enhanced security features for demanding end-use applications due to the high dynamism of their continuous effect (single bar or single double ring) splitting and recombination at a single viewing angle, the effect derived from the method that allows for perfect registration.

[0253] The following items also form part of this disclosure:

[0254] Item 1. A method for producing an optical effect layer (OEL) on a substrate (x10) having a first side and a second side, the optical effect layer (OEL) comprising a first pattern and a second pattern, the first pattern comprising sheet-like magnetic or magnetizable pigment particles with a magnetic orientation according to a first magnetic pattern orientation, and the second pattern comprising sheet-like magnetic or magnetizable pigment particles with a magnetic orientation according to a second magnetic pattern orientation,

[0255] the method comprising:

[0256] a first set of steps comprising:

[0257] a') applying a first radiation-curable coating composition, preferably a first UV-Vis curable coating composition, comprising sheet-like magnetic or magnetizable pigment particles to a first side of the substrate (x10),To form a first coating (x20') on the first side of the substrate (x10), the coating composition being in a first state,

[0258] b') exposing the first radiation-curable coating composition of step a') to the magnetic field of the magnetic component (x30') to magnetically orient at least a portion of the sheet-like magnetic or magnetizable pigment particles, the magnetic component (x30') being located on the second side of the substrate (x10);

[0259] c') at least partially curing the radiation-curable coating composition of step b') to a second state to fix the sheet-like magnetic or magnetizable pigment particles in their adopted positions and orientations, and to produce a first pattern; and

[0260] a second set of steps, comprising:

[0261] a'') registering a second radiation-curable coating composition containing sheet-like magnetic or magnetizable pigment particles. (Pages 41 / 43, CN 122422064 A) A second UV-Vis curable coating composition is preferably applied to a second side of a substrate (x10) to form a second coating (x20'') on the second side of the substrate (x10), the coating composition being in a first state, and at least a portion of the second coating (x20'') being adjacent to at least a portion of the first coating (x20'),

[0262] b'') exposing the second radiation-curable coating composition of step a'') to the magnetic field of a magnetic component (x30''), the magnetic component (x30'') being the same as the magnetic component (x30') used in step b') and located on a first side of the substrate (x10), and the magnetic field in step b'') being substantially the same as the magnetic field in step b'), thereby causing at least a portion of the sheet-like magnetic or magnetizable pigment particles to magnetically orient; and

[0263] c'') The second radiation-curable coating composition of step b'') is at least partially cured to a second state to fix the sheet-like magnetic or magnetizable pigment particles in their adopted positions and orientations, and to produce a second pattern,

[0264] wherein the magnetic field of the magnetic component (x30') in step b') and the magnetic field of the magnetic component (x30'') in step b'') are mirror-symmetric with respect to a surface parallel to the substrate (x10).

[0265] Item 2. The method according to item 1, wherein at least one of step b') and step b'')

[0266] is a one-step magnetic orientation step of uniaxially orienting the sheet-like magnetic or magnetizable pigment particles, or

[0267] is a two-step orientation step comprising a first orientation step of biaxially orienting the sheet-like magnetic or magnetizable pigment particles, followed by a second orientation step of reorienting the sheet-like magnetic or magnetizable pigment particles.

[0268] Item 3. The method according to Item 2, wherein step b') and / or step b'') are independently two-step orientation steps, comprising a first orientation step of biaxially orienting the sheet-like magnetic or magnetizable pigment particles.This is followed by a second orientation step that reorients the flake-like magnetic or magnetizable pigment particles.

[0269] Item 4. The method according to any one of items 1 to 3, wherein step b') and / or step b'') is a two-step orientation step comprising a first orientation step and a subsequent second orientation step, the first orientation step biaxially oriented the flake-like magnetic or magnetizable pigment particles, the second orientation step reorienting the flake-like magnetic or magnetizable pigment particles, and wherein the first orientation step is performed to biaxially oriented at least a portion of the flake-like magnetic or magnetizable pigment particles such that i) both their X-axis and Y-axis are substantially parallel to the surface of the substrate (x10), or ii) a first axis in the XY plane is substantially parallel to the surface of the substrate (x10), and a second axis is perpendicular to the first axis at a substantially non-zero elevation angle to the surface of the substrate (x10), or iii) their XY plane is parallel to the surface of an imaginary sphere.

[0270] Item 5. The method according to any one of items 1 to 4, wherein the first radiation-curable coating composition and the second radiation-curable coating composition exhibit different colors.

[0271] Item 6. The method according to any one of items 1 to 5, wherein steps a') and a'') are performed independently by a printing method selected from the group consisting of screen printing, rotary gravure printing, flexographic printing and gravure printing, preferably by screen printing.

[0272] Item 7. The method according to any one of items 1 to 6, wherein steps c') and b') are performed simultaneously and / or steps c'') and b'') are performed simultaneously.

[0273] Item 8. The method according to item 7, wherein step c') is performed by exposing an LED curing unit (x50) to UV-Vis light radiation, and / or step c'') is performed by exposing an LED curing unit (x50) to UV-Vis light radiation.

[0274] Item 9. The method according to any one of items 1 to 8, wherein at least a portion of the sheet-like magnetic or magnetizable pigment particles is composed of sheet-like optically variable magnetic or magnetizable pigment particles.

[0275] Item 10. The method according to any one of items 1 to 9, wherein the substrate (x10) is selected from the group consisting of: paper or other fibrous materials, paper-containing materials, glass, metal, ceramics, polymers, metallized polymers, at least partially opaque polymers, composite materials, and mixtures or combinations thereof. Specification 42 / 43 pages 45 CN 122422064 A

[0276] Item 11. The method according to item 10, wherein the substrate (x10) is a transparent substrate.

[0277] Item 12. The method according to any one of items 1 to 11, wherein the substrate (x10) comprises a printed pattern, preferably an offset printed pattern.And at least one of the radiation-curable coating compositions of steps a') and a'') is applied at least partially to the printed pattern.

[0278] Item 13. The method according to any one of items 1 to 12, wherein the first coating (x20) and the second coating (x20') are registered within ±1 mm, preferably ±0.5 mm, more preferably ±0.2 mm. Instruction manual, pages 43 / 43, 46 CN 122422064 A, Figure 1, Figure 2, Figure 3, Instruction manual drawing 1 / 5, page 47 CN 122422064 A, Figure 4A-1, Figure 4A-2, Figure 4B, Instruction manual drawing 2 / 5, page 48 CN 122422064 A, Figure 5-1, Figure 5-2, Figure 5-3, Instruction manual drawing 3 / 5, page 49 CN 122422064 A, Figure 6, Figure 7, Figure 8, Instruction manual drawing 4 / 5, page 50 CN 122422064 A, Figure 9, Instruction manual drawing 5 / 5, page 51 CN 122422064 A,

Claims

1. A method for producing an optical effect layer (OEL) on a substrate (x10) having a first side and a second side, the optical effect layer (OEL) comprising a first pattern and a second pattern, the first pattern comprising sheet-like magnetic or magnetizable pigment particles magnetically oriented according to a first magnetic pattern orientation, and the second pattern comprising sheet-like magnetic or magnetizable pigment particles magnetically oriented according to a second magnetic pattern orientation. The method includes: The first set of steps includes: a') Applying a first radiation-curable coating composition, preferably a first UV-Vis-curable coating composition, containing flake-like magnetic or magnetizable pigment particles to a first side of a substrate (x10) to form a first coating (x20') on the first side of the substrate (x10), wherein the coating composition is in a first state. b') Expose the first radiation-curable coating composition of step a') to the magnetic field of the magnetic component (x30') to magnetically orient at least a portion of the sheet-like magnetic or magnetizable pigment particles, the magnetic component (x30') being located on the second side of the substrate (x10); c') Curing at least partially the radiation-curable coating composition of step b') to a second state to fix the flake-like magnetic or magnetizable pigment particles in their adopted positions and orientations, and to produce a first pattern; and The second set of steps includes: a'') A second radiation-curable coating composition, preferably a second UV-Vis-curable coating composition, comprising flake-like magnetic or magnetizable pigment particles, is applied to a second side of a substrate (x10) in a registration manner to form a second coating (x20'') on the second side of the substrate (x10), wherein the coating composition is in a first state, and at least a portion of the second coating (x20'') is adjacent to at least a portion of the first coating (x20'). b'') Exposing the second radiation-curable coating composition of step a'') to the magnetic field of a magnetic component (x30''), said magnetic component (x30'') being the same as the magnetic component (x30') used in step b') and located on the first side of the substrate (x10), and the magnetic field in step b'') being substantially the same as the magnetic field in step b'), thereby causing at least a portion of the sheet-like magnetic or magnetizable pigment particles to magnetically orient; and c'') The second radiation-curable coating composition of step b'') is at least partially cured to a second state to fix the flake-like magnetic or magnetizable pigment particles in their adopted positions and orientations, and to produce a second pattern. The magnetic field of the magnetic component (x30') in step b') and the magnetic field of the magnetic component (x30'') in step b'') are symmetrical with respect to the mirror plane parallel to the substrate (x10). At least a portion of the second coating (x20'') and the first coating (x20') have their projections on each side of the substrate (x10), and at least a portion of the second coating (x20'') and the first coating (x20') are adjacent to at least a portion of the first coating (x20'), which means that their projections on each side of the substrate (x10) are continuous.

2. The method according to claim 1, wherein at least one of step b') and step b'') It is a magnetic orientation step that uniaxially orients sheet-like magnetic or magnetizable pigment particles, or It is a two-step orientation process, which includes a first orientation step that biaxially orients the sheet-like magnetic or magnetizable pigment particles, followed by a second orientation step that re-orients the sheet-like magnetic or magnetizable pigment particles.

3. The method of claim 2, wherein step b') and / or step b'') are independently two-step orientation steps comprising a first orientation step of biaxially orienting the sheet-like magnetic or magnetizable pigment particles, followed by a second orientation step of reorienting the sheet-like magnetic or magnetizable pigment particles.

4. The method according to any one of claims 1 to 3, wherein step b') and / or step b'') is a two-step orientation step comprising a first orientation step and a subsequent second orientation step, the first orientation step biaxially oriented the sheet-like magnetic or magnetizable pigment particles, the second orientation step reorienting the sheet-like magnetic or magnetizable pigment particles, and wherein the first orientation step is performed to biaxially oriented at least a portion of the sheet-like magnetic or magnetizable pigment particles such that i) both their X-axis and Y-axis are substantially parallel to the surface of the substrate (x10), or ii) a first axis in the XY plane is substantially parallel to the surface of the substrate (x10), and a second axis is perpendicular to the first axis at a substantially non-zero elevation angle to the surface of the substrate (x10), or iii) their XY plane is parallel to the surface of an imaginary sphere.

5. The method according to any one of claims 1 to 4, wherein the first radiation-curable coating composition and the second radiation-curable coating composition exhibit different colors.

6. The method according to any one of claims 1 to 5, wherein steps a') and a'') are performed independently by a printing method selected from the group consisting of screen printing, rotary gravure printing, flexographic printing and gravure printing, preferably by screen printing.

7. The method according to any one of claims 1 to 6, wherein step c') and step b') are performed simultaneously and / or step c'') and step b'') are performed simultaneously.

8. The method of claim 7, wherein step c') is performed by exposing the LED curing unit (x50) to UV-Vis light radiation, and / or step c'') is performed by exposing the LED curing unit (x50) to UV-Vis light radiation.

9. The method according to any one of claims 1 to 8, wherein at least a portion of the sheet-like magnetic or magnetizable pigment particles is composed of sheet-like optically variable magnetic or magnetizable pigment particles.

10. The method according to any one of claims 1 to 9, wherein the substrate (x10) is selected from the group consisting of: paper or other fibrous materials, paper-containing materials, glass, metals, ceramics, polymers, metallized polymers, at least partially opaque polymers, composite materials, and mixtures or combinations thereof.

11. The method of claim 10, wherein the substrate (x10) is a transparent substrate.

12. The method according to any one of claims 1 to 11, wherein the substrate (x10) comprises a printed pattern, preferably an offset printed pattern, and wherein at least one of the radiation-curable coating compositions of steps a') and a'') is applied at least partially to the printed pattern.

13. The method according to any one of claims 1 to 12, wherein the first coating (x20') and the second coating (x20'') are within a registration range of ±1 mm, preferably ±0.5 mm, more preferably ±0.2 mm.

14. The method according to any one of claims 1 to 13, wherein the method is a sequential method using a single machine, sequential meaning that the second set of steps is performed directly after the first set of steps, or, if the method includes a third set of steps, the third set of steps is performed directly after the second set of steps.

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