Magnetic devices, magnetic apparatuses and processes for producing optical effect layers comprising oriented non-spherical magnetic or magnetizable pigment particles

Abstract

The present invention relates to the field of magnetic devices, magnetic apparatuses and processes for producing optical effect layers (OEL) comprising magnetically oriented non-spherical magnetic or magnetizable pigment particles on a substrate and providing an optical impression of two or more loop-shaped bodies having their shape and / or size and / or their brightness varying in opposite directions upon tilting the optical effect layer (OEL). In particular, the present invention relates magnetic devices, magnetic apparatuses and processes for producing said OELs as anti-counterfeit means on security documents or security articles or for decorative purposes.

Description

SICPA HOLDING SA 272 626 t8MAGNETIC DEVICES, MAGNETIC APPARATUSES AND PROCESSES FOR PRODUCING OPTICAL EFFECT LAYERS COMPRISING ORIENTED NON-SPHERICAL MAGNETIC OR MAGNETIZABLE PIGMENT PARTICLESFIELD OF THE INVENTION

[0001] The present invention relates to the field of the protection of value documents and value or branded commercial goods against counterfeit and illegal reproduction. In particular, the present invention relates to magnetic devices, magnetic apparatuses and processes for producing optical effect layers (OELs) showing a viewing-angle dynamic appearance and optical effect layers obtained thereof, as well as to uses of said OELs as anti-counterfeit means on documents and articles.BACKGROUND OF THE INVENTION

[0002] The use of inks, coating compositions, coatings, or layers, containing magnetic or magnetizable pigment particles, in particular non-spherical optically variable magnetic or magnetizable pigment particles, for the production of security elements and security documents is known in the art.

[0003] Security features for security documents and articles can be classified into “covert” and “overt” security features. The protection provided by covert security features relies on the concept that such features are hidden to the human senses, typically requiring specialized equipment and knowledge for their detection, whereas “overt” security features are easily detectable with the unaided human senses. Such features may be visible and / or detectable via the tactile senses while still being difficult to produce and / or to copy. However, the effectiveness of overt security features depends to a great extent on their easy recognition as a security feature because users will only then actually perform a security check based on such security feature if they are aware of its existence and nature.

[0004] Coatings or layers comprising 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. Magnetic or magnetizable pigment particles in coatings allow for the production of magnetically induced images, designs and / or patterns through the application of a corresponding magnetic field, causing a local orientation of the magnetic or magnetizable pigment particles in the unhardened coating, followed by hardening the latter to fix the particles in their positions and orientations. This results in specific optical effects, i.e. fixed magnetically induced images, designs or patterns which are highly resistant to counterfeiting. The security elements based on oriented magnetic or magnetizable pigment particles can only be produced by having access to both, the magnetic or magnetizable pigment particles or a corresponding ink or coating composition comprising said particles, and the particular technology employed for applying said ink or coating composition and for orienting said pigment particles in the applied ink or coating composition, followed by hardening said ink or composition.

[0005] A particularly striking optical effect can be achieved if a security feature changes its appearance upon a change in viewing conditions, such as the viewing angle. One example is the so-called “rolling bar” effect, as disclosed in US 2005 / 0106367. A “rolling bar” effect is based on pigment particles orientation imitating a curved surface across the coating. The observer sees a specular reflection zone which moves away or towards the observer as the image is tilted. This effect is nowadays utilized for a number of security elements on banknotes, such as on the “5” and the ”10” of the 5 respectively 10SICPA HOLDING SA 272 626 t8Euro banknote.

[0006] Other particularly striking optical effects and methods to produce them are disclosed in US 2015 / 0146280. According to the invention disclosed in US 2015 / 0146280, the optical effects show a dynamic visual motion effect upon tilting such that one part of the image appears to move in a different plane than the rest of the image.

[0007] Further particularly striking optical effects providing a specular reflection zone having a shape of a loop which appears to increase or decrease in size upon tilting the substrate carrying the optical effect coating layer are disclosed in WO 2017 / 148789 A1 .

[0008] Methods for producing optical effects having parts of the image moving in different direction as the rest of the image include the use of photomasks as disclosed in US 2017 / 0253070 or selective curing as disclosed in US 2011 / 221431 and US 2022 / 088635.

[0009] A need remains for magnetic devices, magnetic apparatuses and processes for producing optical effect layers (OELs) based on magnetically oriented pigment particles, wherein said magnetic devices, magnetic apparatuses and processes are reliable, easy to implement and able to work at a high production speed while allowing the production of eye catching OELs exhibiting a dynamic effect and being difficult to produce on a mass-scale with the equipment available to a counterfeiter, in particular OELs exhibiting areas appearing to move and / or change size in opposite directions upon tilting of the substrate.SUMMARY OF THE INVENTION

[0010] Accordingly, it is an object of the present invention to provide magnetic devices (100) for producing optical effect layers (OELs) on substrates (120), said OELs providing an optical impression of two or more loop-shaped bodies having their shape and / or size and / or their brightness varying in opposite directions upon tilting said OELs.[Oil] The magnetic device (100) is configured for receiving the substrate (120) in an orientation substantially parallel to a first plane and above the first plane, and comprises: a) a magnetic assembly (130) comprising a non-magnetic supporting matrix (135), a first set S1 and a second set S2 at least partially embedded in the non-magnetic supporting matrix (135), each set S1 and S2 independently comprising a1) a pair of first bar dipole magnets, each pair independently comprising a first first bar dipole magnet (131 a; 131 b) and a second first bar dipole magnet (131 a’; 131 b’) having their magnetic axis substantially parallel to the first plane, the first first bar dipole magnet (131 a) of the first set S1 and the second first bar dipole magnet (131 a’) of the first set S1 having an opposite magnetic direction, and the first first bar dipole magnet (131 b) of the second set S2 and the second first bar dipole magnet (131 b’) of the second set S2 having an opposite magnetic direction, the first first bar dipole magnet (131 a) of the first set S1 and the first first bar dipole magnet (131 b) of the second set S2 having an opposite magnetic direction, and the second first bar dipole magnet (131 a’) of the first set S1 and the second first bar dipole magnet (131 b’) of the second set S2 having an opposite magnetic direction,SICPA HOLDING SA 272 626 t8 the first first bar dipole magnets (131 a; 131 b) of the first set S1 and of the second set S2 being both arranged on a side of a virtual quadrangle and the second first bar dipole magnets (131 a’; 131 b’) of the first set S1 and of the second set S2 being both arranged on an opposite side of the virtual quadrangle, the first first bar dipole magnet (131 b) of the second set S2 being arranged at a distance d3 from the first first bar dipole magnet (131 a) of the first set S1 , the second first bar dipole magnet (131 b’) of the second set S2 being arranged at the distance d3 from the second first bar dipole magnet (131 a’) of the first set S1 , and a2) a second dipole magnet (132a; 132b) having a magnetic axis substantially perpendicular to the first plane, the second dipole magnet (132a) of the first set S1 being arranged between the first first bar dipole magnet (131 a) and the second first bar dipole magnet (131 a’) of said first set S1 , the second dipole magnet (132b) of the second set S2 being arranged between the first first bar dipole magnet (131 b) and the second first bar dipole magnet (131 b’) of said second set S2, the second dipole magnet (132a) of the first set S1 and the second dipole magnet (132b) of the second set S2 having an opposite magnetic direction, the second dipole magnet (132a) of the first set S1 having its South Pole pointing towards the first plane when the first first bar dipole magnet (131 a) and the second first bar dipole magnet (131 a’) of said first set S1 have their South Poles pointing towards the periphery of the magnetic assembly (130) of the magnetic device (100) orthe second dipole magnet (132a) of the first set S1 having its North Pole pointing towards the first plane when the first first bar dipole magnet (131 a) and the second first bar dipole magnet (131 a’) of said first set S1 have their North Poles pointing towards the periphery of the magnetic assembly (130) of the magnetic device (100); b) a magnetic-field generating device (140) being a bar dipole magnet having a magnetic axis substantially parallel to the first plane, and c) a pole piece (150), wherein the magnetic-field generating device (140) is arranged on top of the magnetic assembly (130) and the magnetic assembly (130) is arranged on top of the pole piece (150) or wherein the magnetic assembly (130) is arranged on top of the magnetic-field generating device (140) and the magnetic-field generating device (140) is arranged on top of the pole piece (150).

[0012] Also described herein are the magnetic devices (100) described herein further comprising in the magnet assembly (130) a pair of a first third bar dipole magnet (133a) and a second third bar dipole magnet (133b) arranged on two substantially parallel sides of the virtual quadrangle lacking the first first bar dipole magnets (131 a and 131 b) and lacking the second first bar dipole magnets (131 a’ and 131 b’), said two substantially parallel sides being substantially perpendicular to the sides of the virtual quadrangle comprising the first first bar dipole magnets (131 a and 131 b) and the second first bar dipole magnets (131 a’ and 131 b’), wherein said third bar dipole magnets (133a, 133b) have a magnetic axis substantially parallel to the first plane, have a same magnetic direction, with the North Pole of the first third bar dipole magnet (133a) pointing towards the second dipole magnet (132a) of the first set S1 ,SICPA HOLDING SA 272 626 t8 when said second dipole magnet (132a) of the first set S1 has its South Pole pointing towards the first plane or has its South Pole pointing towards the second dipole magnet (132a) of the first set S1 when said second dipole magnet (132a) of the first set S1 has its North Pole pointing towards the first plane.

[0013] Also described herein are the magnetic devices (100) described herein further comprising in the magnet assembly (130) a fourth bar dipole magnet (134) arranged on a virtual line of the virtual quadrangle being substantially perpendicular to the sides of the virtual quadrangle comprising the first first bar dipole magnets (131 a; 131 b) and the second first bar dipole magnets (131 a’; 131 b’) and between the first set S1 and the second set S2, said fourth bar dipole magnet (134) having a magnetic axis substantially parallel to the first plane, with the North pole of said fourth bar dipole magnet (134) pointing towards the second dipole magnet (132a or 132b) having its South pole pointing towards the first plane.

[0014] Also described herein are the magnetic devices (100) described herein further comprising in the magnetic assembly (130) the pair of a first third bar dipole magnet (133a) and a second third bar dipole magnet (133b) described herein and the fourth bar dipole magnet (134) described herein.

[0015] Also described herein are the magnetic devices (100) described herein further comprising an engraved plate (160), wherein said engraved plate (160) is arranged on top of the magnetic-field generating device (140) or on top of the magnetic assembly (130).

[0016] Also described herein are uses of the magnetic devices (100) described herein for producing the optical effect layer (OEL) on the substrate (120) described herein.

[0017] Also described herein are magnetic apparatuses (1000) comprising the magnetic device (100) described herein, a holding case (170) and a holding case bottom lid (171), wherein said holding case (170) comprises a cavity for receiving the magnetic device (100) described herein and is arranged on top of the magnetic-field generating device (140) or on top of the magnetic assembly (130).

[0018] Also described herein are magnetic apparatuses (1000) described herein further comprising an engraved plate (160), wherein said engraved plate (160) is arranged on top of said holding case (170), provided that the magnetic device (100) does not comprise an engraved plate. In other words, for embodiments wherein the magnetic device (100) comprises the engraved plate (160) described herein, the magnetic apparatus (1000) does not comprise an additional engraved plate (160).

[0019] Also described herein are uses of the magnetic apparatuses described herein for producing the optical effect layer (OEL) on the substrate (120) described herein.

[0020] Also described herein are processes for producing the optical effect layer (OEL) described herein on the substrate (120) described herein, said processes comprising the steps of: i) applying on the substrate (120) a radiation curable coating composition comprising non-spherical magnetic or magnetizable pigment particles, said radiation curable coating composition being in a first state so as to form a coating layer (110); ii) exposing the radiation curable coating composition to a magnetic field of the magnetic device (100) described herein or of the magnetic apparatus (1000) described herein so as to magnetically orient at least a part of the non-spherical magnetic or magnetizable pigment particles;SICPA HOLDING SA 272 626 t8 iii) at least partially curing the radiation curable coating composition of step ii) to a second state so as to fix the non-spherical magnetic or magnetizable pigment particles in their adopted positions and orientations.

[0021] Also described herein are methods of manufacturing a security document or article or a decorative element or article, comprising a) providing a security document or article or a decorative element or object, and b) producing the optical effect layer (OEL) with the process described herein, so that the optical effect layer (OEL) is comprised by or on the security document or article or the decorative element or the object.

[0022] The present invention provides magnetic devices (100) and magnetic apparatuses (1000) advantageously allowing the manufacture of bright and eye-catching optical effect layers (OELs), in the form of single coating layers on a substrate (120), said OELs providing a visually distinct optical impression of opposite movements, as determinable by the human eye, in particular distinct optical impressions of two or more loop-shaped bodies having their shape and / or size and / or their brightness varying in opposite directions upon tilting the optical effect layer OELs, said OELs being produced by a process comprising an applying step, an orientation step and a curing step without requiring any selective curing step or use of a photomask.BRIEF DESCRIPTION OF DRAWINGSFigs 1A-G schematically illustrate magnetic apparatuses (1000) for producing an optical effect layer (OEL) on a substrate (120) according to the present invention, wherein the apparatuses (1000) comprise a) a magnetic device (100) comprising a magnetic assembly (130), a magnetic-field generating device (140) and a pole piece (150) and b) comprise a holding case (170) and a holding case bottom lid (171).Fig. 1 H schematically illustrates an example of a magnetic device (100) according to the present invention, said device (100) comprising a magnetic-field generating device (140), a magnetic assembly (130) and a pole piece (150), the magnetic assembly (130) comprising three sets S1 , S2 and S3, each set comprising a first first bar dipole magnet (131 a, 131 b, 131 c), a second first bar dipole magnet (131 a’, 131 b’, 131 c’) and a second dipole magnet (132a , 132 b, 132 c).Figs 2A-D schematically illustrate magnetic assemblies (130) comprising a non-magnetic supporting matrix (135); a first set S1 comprising a first first bar dipole magnet (131 a), a second first bar dipole magnet (131 a’) and a second dipole magnet (132a); and a second set S2 comprising a first first bar dipole magnet (131 b), a second first bar dipole magnet (131 b’) and a second dipole magnet (132b), wherein all magnets are at least partially embedded in the non-magnetic supporting matrix (135). As shown in Fig. 2A, the first first bar dipole magnets (131 a; 131 b) of the first set S1 and of the second set S2 are arranged on a side of a virtual quadrangle Q in the form of a virtual rectangle and the second first bar dipole magnets (131 a’; 131 b’) of the first set S1 and of the second set S2 are arranged on the opposite side of the virtual quadrangle, the second dipole magnet (132a) of the first set S1 is arranged between the first first bar dipole magnet (131 a) and the second first bar dipole magnet (131 a’) of said first set S1 , and the second dipole magnet (132b) of the second set S2 is arranged between the first first bar dipole magnet (131 b) and the second first bar dipole magnet (131 b’) of said second set S2.SICPA HOLDING SA 272 626 t8Figs 2E-G schematically illustrate magnetic assemblies (130) comprising a non-magnetic supporting matrix (135); a first set S1 comprising a first first bar dipole magnet (131 a), a second first bar dipole magnet (131 a’) and a combination of more than two (five in Fig. 2E, four in Fig. 2F and six in Fig. 2G) second dipole magnets (132a1 i, i = 5 in Fig. 2E, i= 4 in Fig. 2F and i = 6 in Fig. 2G); and a second set S2 comprising a first first bar dipole magnet (131 b), a second first bar dipole magnet (131 b’) and a combination of more than two (five in Fig. 2E, four in Fig. 2F and six in Fig. 2G) second dipole magnets (132b1 i, i = 5 in Fig. 2E, i = 4 in Fig. 2F and i = 6 in Fig. 2G), wherein all magnets are at least partially embedded in the non-magnetic supporting matrix (135). The first first bar dipole magnets (131 a; 131 b) of the first set S1 and of the second set S2 are arranged on a side of a virtual quadrangle (not shown in the Figures) in the form of a virtual rectangle and the second first bar dipole magnets (131 a’; 131 b’) of the first set S1 and of the second set S2 are arranged on the opposite side of the virtual quadrangle, the combination of more than two second dipole magnets (132a1 i) of the first set S1 are arranged between the first first bar dipole magnet (131 a) and the second first bar dipole magnet (131 a’) of said first set S1 on virtual line (not shown in Fig. 2E), on the sides of a virtual square Q’ (Fig. 2F) or on the sides of a virtual rectangle Q” (Fig. 2G), and the combination of more than two second dipole magnets (132b1 i) of the second set S2 are arranged between the first first bar dipole magnet (131 b) and the second first bar dipole magnet (131 b’) of said second set S2 on virtual line (not shown in Fig. 2E), on the sides of a virtual square Q’ (Fig. 2F) or on the sides of a virtual rectangle Q” (Fig. 2G).Figs 3A-D schematically illustrate magnetic assemblies (130) comprising a non-magnetic supporting matrix (135); a first set S1 comprising a first first bar dipole magnet (131 a), a second first bar dipole magnet (131 a’) and a second dipole magnet (132a); and a second set S2 comprising a first first bar dipole magnet (131 b), a second first bar dipole magnet (131 b’) and a second dipole magnet (132b); and a pair of a first third bar dipole magnet (133a) and a second third bar dipole magnet (133b), wherein all magnets are at least partially embedded in the non-magnetic supporting matrix (135). As shown in Fig. 3A, the first first bar dipole magnets (131 a; 131 b) of the first set S1 and of the second set S2 are arranged on a side of a virtual quadrangle Q in the form of a virtual rectangle, the second first bar dipole magnets (131 a’; 131 b’) of the first set S1 and of the second set S2 are arranged on the opposite side of the virtual quadrangle, the second dipole magnet (132a) of the first set S1 is arranged between the first first bar dipole magnet (131 a) and the second first bar dipole magnet (131 a’) of said first set S1 , and the second dipole magnet (132b) of the second set S2 is arranged between the first first bar dipole magnet (131 b) and the second first bar dipole magnet (131 b’) of said second set S2, the first third bar dipole magnet (133a) is arranged on a side of the virtual quadrangle substantially perpendicular to the sides comprising the first first bar dipole magnets (131 a; 131 b) and the second first bar dipole magnets (131 a’; 131 b’) and the second third bar dipole magnet (133b) is arranged on the side of the virtual quadrangle opposite to the side comprising the first third bar dipole magnet (133a), said opposite side being substantially perpendicular to the sides comprising the first first bar dipole magnets (131 a; 131 b) and the second first bar dipole magnets (131 a’; 131 b’).Fig. 3E schematically illustrates a magnetic assembly (130) comprising a non-magnetic supporting matrix (135); a first set S1 comprising a first first bar dipole magnet (131 a), a second first bar dipole magnet (131 a’) and a combination of four second dipole magnets (132a1-4); a second set S2 comprisingSICPA HOLDING SA 272 626 t8 a first first bar dipole magnet (131 b), a second first bar dipole magnet (131 b’) and a combination of four second dipole magnets (132b1-4); and a pair of a first third bar dipole magnet (133a) and a second third bar dipole magnet (133b), wherein all magnets are at least partially embedded in the non-magnetic supporting matrix (135). The first first bar dipole magnets (131 a; 131 b) of the first set S1 and of the second set S2 are arranged on a side of a virtual quadrangle (not shown in the Figure) in the form of a virtual rectangle, the second first bar dipole magnets (131 a’; 131 b’) of the first set S1 and of the second set S2 are arranged on the opposite side of the virtual quadrangle, the combination of the four second dipole magnets (132a1-4) of the first set S1 are arranged between the first first bar dipole magnet (131 a) and the second first bar dipole magnet (131 a’) of said first set S1 on the sides of a virtual square Q’, and the combination of the four dipole magnets (132b1-4) of the second set S2 are arranged between the first first bar dipole magnet (131 b) and the second first bar dipole magnet (131 b’) of said second set S2 on the sides of a virtual square Q’ (not shown in the Figure), the first third bar dipole magnet (133a) is arranged on a side of the virtual quadrangle substantially perpendicular to the sides comprising the first first bar dipole magnets (131 a; 131 b) and the second first bar dipole magnets (131 a’; 131 b’) and the second third bar dipole magnet (133b) is arranged on the opposite side of the virtual quadrangle, said opposite side being substantially perpendicular to the sides comprising the first first bar dipole magnets (131 a; 131 b) and the second first bar dipole magnets (131 a’; 131 b’).Fig. 4A schematically illustrates a magnetic assembly (130) comprising a non-magnetic supporting matrix (135); a first set S1 comprising a first first bar dipole magnet (131 a), a second first bar dipole magnet (131 a’) and a second dipole magnet (132a); a second set S2 comprising a first first bar dipole magnet (131 b), a second first bar dipole magnet (131 b’), a second dipole magnet (132b); and a fourth bar dipole magnet (134), wherein all magnets are at least partially embedded in the non-magnetic supporting matrix (135). As shown in Fig. 4A, the first first bar dipole magnets (131 a; 131 b) of the first set S1 and of the second set S2 are arranged on a side of a virtual quadrangle Q in the form of a virtual rectangle, the second first bar dipole magnets (131 a’; 131 b’) of the first set S1 and of the second set S2 are arranged on the opposite side of the virtual quadrangle, the second dipole magnet (132a) of the first set S1 is arranged between the first first bar dipole magnet (131 a) and the second first bar dipole magnet (131 a’) of said first set S1 , and the second dipole magnet (132b) of the second set S2 is arranged between the first first bar dipole magnet (131 b) and the second first bar dipole magnet (131 b’) of said second set S2, and the fourth bar dipole magnet (134) is arranged on a virtual line L in the virtual quadrangle being substantially perpendicular to the sides of the virtual quadrangle comprising the first first bar dipole magnets (131 a; 131 b) and the second first bar dipole magnets (131 a’; 131 b’) and is arranged between the first set S1 and the second set S2.Fig. 4B schematically illustrates a magnetic assembly (130) comprising a non-magnetic supporting matrix (135); a first set S1 comprising a first first bar dipole magnet (131 a), a second first bar dipole magnet (131 a’) and a combination of four second dipole magnets (132a1-4); a second set S2 comprising a first first bar dipole magnet (131 b), a second first bar dipole magnet (131 b’) and a combination of four second dipole magnets (132b1-4); and a fourth bar dipole magnet (134), wherein all magnets are at least partially embedded in the non-magnetic supporting matrix (135). The first first bar dipole magnets (131 a; 131 b) of the first set S1 and of the second set S2 are arranged on a side of a virtual quadrangle (notSICPA HOLDING SA 272 626 t8 shown in the Figure) in the form of a virtual rectangle, the second first bar dipole magnets (131 a’; 131 b’) of the first set S1 and of the second set S2 are arranged on the opposite side of the virtual quadrangle, the combination of the four second dipole magnets (132a1-4) of the first set S1 are arranged between the first first bar dipole magnet (131 a) and the second first bar dipole magnet (131 a’) of said first set S1 on the sides of a virtual square Q’, and the combination of the four dipole magnets (132b1-4) of the second set S2 are arranged between the first first bar dipole magnet (131 b) and the second first bar dipole magnet (131 b’) of said second set S2 on the sides of a virtual square Q’ (not shown in the Figure), and the fourth bar dipole magnet (134) is arranged on a virtual line (not shown in the Figure) in the virtual quadrangle being substantially perpendicular to the sides of the virtual quadrangle comprising the first first bar dipole magnets (131 a; 131 b) and the second first bar dipole magnets (131 a’; 131 b’) and is arranged between the first set S1 and the second set S2.Fig. 5A schematically illustrates a magnetic assembly (130) comprising a non-magnetic supporting matrix (135); a first set S1 comprising a first first bar dipole magnet (131 a), a second first bar dipole magnet (131 a’) and a second dipole magnet (132a); a second set S2 comprising a first first bar dipole magnet (131 b), a second first bar dipole magnet (131 b’) and a second dipole magnet (132b); a pair of a first third bar dipole magnet (133a) and a second third bar dipole magnet (133b); and a fourth bar dipole magnet (134), wherein all magnets are at least partially embedded in the non-magnetic supporting matrix (135). As shown in Fig.5A, the first first bar dipole magnets (131 a; 131 b) of the first set S1 and of the second set S2 are arranged on a side of a virtual quadrangle Q in the form of a virtual rectangle, the second first bar dipole magnets (131 a’; 131 b’) of the first set S1 and of the second set S2 are arranged on the opposite side of the virtual quadrangle, the second dipole magnet (132a) of the first set S1 is arranged between the first first bar dipole magnet (131 a) and the second first bar dipole magnet (131 a’) of said first set S1 , and the second dipole magnet (132b) of the second set S2 is arranged between the first first bar dipole magnet (131 b) and the second first bar dipole magnet (131 b’) of said second set S2, the first third bar dipole magnet (133a) is arranged on a side of the virtual quadrangle substantially perpendicular to the sides comprising the first first bar dipole magnets (131 a; 131 b) and the second first bar dipole magnets (131 a’; 131 b’), the second third bar dipole magnet (133b) is arranged on the side of the virtual quadrangle opposite to the side comprising the first third bar dipole magnet (133a), said opposite side being substantially perpendicular to the sides comprising the first first bar dipole magnets (131 a; 131 b) and the second first bar dipole magnets (131 a’; 131 b’) and the fourth bar dipole magnet (134) arranged on a virtual line L in the virtual quadrangle being substantially perpendicular to the sides of the virtual quadrangle comprising the first first bar dipole magnets (131 a; 131 b) and the second first bar dipole magnets (131 a’; 131 b’) and between the first set S1 and the second set S2.Fig. 5B schematically illustrates a magnetic assembly (130) comprising a non-magnetic supporting matrix (135); a first set S1 comprising a first first bar dipole magnet (131 a), a second first bar dipole magnet (131 a’) and a combination of four second dipole magnets (132a1-4); a second set S2 comprising a first first bar dipole magnet (131 b), a second first bar dipole magnet (131 b’) and a combination of four second dipole magnets (132b1-4); a pair of a first third bar dipole magnet (133a) and a second third bar dipole magnet (133b); and a fourth bar dipole magnet (134), wherein all magnets are at least partiallySICPA HOLDING SA 272 626 t8 embedded in the non-magnetic supporting matrix (135). The first first bar dipole magnets (131 a; 131 b) of the first set S1 and of the second set S2 are arranged on a side of a virtual quadrangle (not shown in the Figure) in the form of a virtual rectangle, the second first bar dipole magnets (131 a’; 131 b’) of the first set S1 and of the second set S2 are arranged on the opposite side of the virtual quadrangle, the combination of the four second dipole magnets (132a1-4) of the first set S1 are arranged between the first first bar dipole magnet (131 a) and the second first bar dipole magnet (131 a’) of said first set S1 on the sides of a virtual square Q’, and the combination of the four dipole magnets (132b1-4) of the second set S2 are arranged between the first first bar dipole magnet (131 b) and the second first bar dipole magnet (131 b’) of said second set S2 on the sides of a virtual square Q’ (not shown in the Figure), the first third bar dipole magnet (133a) is arranged on a side of the virtual quadrangle substantially perpendicular to the sides comprising the first first bar dipole magnets (131 a; 131 b) and the second first bar dipole magnets (131 a’; 131 b’), the second third bar dipole magnet (133b) is arranged on the side of the virtual quadrangle opposite to the side comprising the first third bar dipole magnet (133a), said opposite side being substantially perpendicular to the sides comprising the first first bar dipole magnets (131 a; 131 b) and the second first bar dipole magnets (131 a’; 131 b’) and the fourth bar dipole magnet (134) is arranged on a virtual line (not shown in the Figure) in the virtual quadrangle being substantially perpendicular to the sides of the virtual quadrangle comprising the first first bar dipole magnets (131 a; 131 b) and the second first bar dipole magnets (131 a’; 131 b’) and between the first set S1 and the second set S2.Fig.6B shows pictures of OELs obtained by using the apparatus and process described herein, said OELs being tilted up and down from -30° to +30° (see “V” direction in Fig. 6A) or left and right from - 30° to +30° (see “H” in Fig. 6A).

[0023] The distances provided in the Figures are only illustrative and are not true to scale.DETAILED DESCRIPTIONDEFINITIONS

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

[0025] As used herein, the indefinite article "a" indicates one as well as more than one and does not necessarily limit its referent noun to the singular.

[0026] As used herein, the term “at least” is meant to define one or more than one, for example one or two or three.

[0027] As used herein, the term “at least n”, wherein n is a integer, is meant to define n or more than n, for example n+1 or n+2 (i.e. in case of “at least one”, it is meant one, two .three, etc.; in case of “at least two”, it is meant two, three, four, etc.)

[0028] As used herein, the term “about” means that the amount or value in question may be the specific value designated or some other value in its neighborhood. Generally, the term “about” denoting a certain value is intended to denote a range within ± 5% of the value. As one example, the phrase “about 100”SICPA HOLDING SA 272 626 t8 denotes a range of 100 ± 5, i.e. the range from 95 to 105. Generally, when the term “about” is used, it can be expected that similar results or effects according to the invention can be obtained within a range of ±5% of the indicated value.

[0029] As used herein, the term “and / or” means that either all or only one of the elements of said group may be present. For example, “A and / or B” shall 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 absent, i.e. “only A, but not B”.

[0030] The term “comprising” as used herein is intended to be non-exclusive and open-ended. Thus, for instance a coating composition comprising a compound A may include other compounds besides A. However, the term “comprising” also covers, as a particular embodiment thereof, the more restrictive meanings of “consisting essentially of’ and “consisting of’, so that for instance “a composition comprising A, B and optionally C” may also (essentially) consist of A and B, or (essentially) consist of A, B and C.

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

[0032] As used herein, the term “wet” refers to a coating layer which is not yet cured, for example a coating in which the platelet-shaped magnetic or magnetizable pigment particles are still able to change their positions and orientations under the influence of external forces acting upon them.

[0033] A “pigment particle”, in the context of the present disclosure, designates a particulate material, which is insoluble in the ink or coating composition, and which provides the latter with specific spectral properties (e.g. opacity, color or colorshift).

[0034] The term “magnetic axis” denotes a theoretical line connecting the magnetic centers of the North- and South-pole faces of a magnet and extending through said pole faces. This term does not include any specific magnetic field direction.

[0035] The term “magnetic direction” denotes the direction of the magnetic field vector along a magnetic field line pointing, at the exterior of a magnet, from its North pole to its South pole (see Handbook of Physics, Springer 2002, pages 463-464).

[0036] The term “substantially parallel” refers to deviating not more than 10° from parallel alignment and the term “substantially perpendicular” refers to deviating not more than 10° from perpendicular alignment.

[0037] The term “optical effect layer (OEL)” as used herein denotes a coating or layer that comprises oriented magnetic or magnetizable pigment particles and a binder, wherein said magnetic or magnetizable pigment particles are oriented by a magnetic field and wherein the oriented plateletshaped magnetic or magnetizable pigment particles are fixed / frozen in their orientation and position (i.e. after hardening / curing) so as to form a magnetically induced image.

[0038] As used herein, the term “indicia” shall mean continuous or discontinuous layers such as patterns, including without limitation symbols, alphanumeric symbols, motifs, letters, words, numbers, logos and drawings.SICPA HOLDING SA 272 626 t8

[0039] The term "security document or article" refers to a document or article which is usually protected against counterfeit or fraud by at least one security feature. Examples of security documents and articles include without limitation value documents and value commercial goods.

[0040] The term “security feature” is used to denote an image, pattern or graphic element that can be used for authentication purposes.

[0041] The terms “above”, “below”, “top” and “bottom” define the relative position of the different elements and do not limit and define their absolute position.

[0042] Where the present description refers to “preferred” embodiments / features, combinations of these “preferred” embodiments / features shall also be deemed as disclosed as long as this combination of “preferred” embodiments / features is technically meaningful.

[0043] The present invention provides magnetic devices (100), magnetic apparatuses (1000) and processes using said magnetic devices (100) and apparatuses (1000) for producing optical effect layers (OELs), said OELs comprising a plurality of non-randomly oriented non-spherical magnetic or magnetizable pigment particles, said pigment particles being dispersed within a cured material and OELs obtained thereof. Thanks to the orientation pattern of said magnetic or magnetizable pigment particles, the OEL described herein provides the optical impression of two or more loop-shaped bodies, wherein said two or more loop-shaped bodies have their shape and / or size and / or their brightness varying in opposite directions upon tilting the OEL. Advantageously, the process described herein allows the production of highly eye-catching OELs in the form of a single coating layer on a substrate, said OELs being produced by a process comprising an applying step, an orientation step and a curing step without required any selective curing step.

[0044] The magnetic devices (100) and magnetic apparatuses (1000) described herein are configured for receiving the substrate (120) described herein in an orientation substantially parallel to a first plane.

[0045] The magnetic device (100) described herein comprises the magnetic assembly (130) described herein, the magnetic-field generating device (140) described herein, the pole piece (150) described herein and optionally the engraved plate (160) described herein; wherein the magnetic assembly (130) may optionally comprise the pair of the first third bar dipole magnet (133a) and the second third bar dipole magnet (133b) described herein, and optionally the fourth bar dipole magnet (134) described herein. According to one embodiment shown for example in Figs 1A-C and 1 H, the magnetic-field generating device (140) is arranged on top of the magnetic assembly (130) and the magnetic assembly (130) is arranged on top of the pole piece (150); according to another embodiment shown in Figs 1 D- 1 G, the magnetic assembly (130) is arranged on top of the magnetic-field generating device (140) and the magnetic-field generating device (140) is arranged on top of the pole piece (150). When present, the engraved plate (160) is either arranged on top of the magnetic-field generating device (140) or is arranged on top of the magnetic assembly (130). Preferably and as shown in Figs 1 , the magnetic assembly (130), the magnetic-field generating device (140) and the pole piece (150) are essentially centered with respect to one another.

[0046] For embodiments wherein the magnetic device (100) does not comprise the engraved plate (160) described herein, the magnetic apparatuses (1000) described herein comprise the magneticSICPA HOLDING SA 272 626 t8 device (100) described herein, the holding case (170) described herein and the holding case bottom lid (171) described herein. When present, the engraved plate (160) is preferably arranged on top of the holding case (170).

[0047] The present invention provides processes for producing the optical effect layer (OEL) described herein on the substrate described herein, and the OELs obtained therewith, wherein said processes comprise a step i) of applying on the substrate (120) surface the radiation curable coating composition comprising the non-spherical magnetic or magnetizable pigment particles described herein, said radiation curable coating composition being in a first state, i.e. a liquid or pasty state, wherein the radiation curable coating composition is wet or soft enough, so that the non-spherical magnetic or magnetizable pigment particles dispersed in the radiation curable coating composition are freely movable, rotatable and / or orientable upon exposure to the magnetic field. The step i) described herein may be carried out by a coating process such as for example roller and spray coating processes or by a printing process. Preferably, the step i) described herein is carried out by a printing process preferably selected from the group consisting of screen printing, rotogravure printing, flexography printing, inkjet printing and intaglio printing (also referred in the art as engraved copper plate printing and engraved steel die printing), more preferably selected from the group consisting of screen printing, rotogravure printing and flexography printing.

[0048] Subsequently to, partially simultaneously with or simultaneously with the application of the radiation curable coating composition described herein on the substrate surface described herein (step i)), at least a part of the non-spherical magnetic or magnetizable pigment particles are oriented (step ii)) by exposing the radiation curable coating composition to the magnetic field of the magnetic device (100) or of the magnetic apparatus (1000) described herein, so as to align at least a part of said non- spherical magnetic or magnetizable pigment particles along the magnetic field lines generated by the magnetic device (100) or by the magnetic apparatus (1000).

[0049] Subsequently to or partially simultaneously with the step of orienting / aligning at least a part of the non-spherical magnetic or magnetizable pigment particles by applying the magnetic field described herein, the orientation of the non-spherical magnetic or magnetizable pigment particles is fixed or frozen. The radiation curable coating composition must thus noteworthy have a first state, i.e. a liquid or pasty state, wherein the radiation curable coating composition is wet or soft enough, so that the non- spherical magnetic or magnetizable pigment particles dispersed in the radiation curable coating composition are freely movable, rotatable and / or orientable upon exposure to the magnetic field, and a second cured (e.g. solid) state, wherein the non-spherical magnetic or magnetizable pigment particles are fixed or frozen in their respective positions and orientations. Accordingly, the processes for producing an optical effect layer (OEL) on the substrate (120) described herein comprises a step iii) of at least partially curing the radiation curable coating composition of step ii) to a second state so as to fix the non-spherical magnetic or magnetizable pigment particles in their adopted positions and orientations. As used herein, by “at least partially curing the radiation curable coating composition”, it means that the non-spherical magnetic or magnetizable pigment particles are fixed / frozen in their adopted positions and orientations and cannot move and rotate anymore (also referred in the art as “pinning” of the particles). The step iii) of at least partially curing the radiation curable coatingSICPA HOLDING SA 272 626 t8 composition may be carried out subsequently to or partially simultaneously with the step of orienting / aligning at least a part of the non-spherical magnetic or magnetizable pigment particles by applying the magnetic field described herein (step ii)). Preferably, the step iii) of at least partially curing the radiation curable coating composition is carried out partially simultaneously with the step of orienting / aligning at least a part of the non-spherical magnetic or magnetizable pigment particles by applying the magnetic field described herein (step ii)). By “partially simultaneously”, it is meant that both steps are partly performed simultaneously, i.e. the times of performing each of the steps partially overlap.

[0050] In the context described herein, when the at least partially curing step (step iii)) is performed partially simultaneously with the orientation step ii), it must be understood that curing becomes effective after the orientation so that the pigment particles orient before the complete or partial curing of the OEL.

[0051] The first and second states of the radiation curable coating composition are provided by using a certain type of radiation curable coating composition. For example, the components of the radiation curable coating composition other than the non-spherical magnetic or magnetizable pigment particles may take the form of an ink or radiation curable coating composition such as those which are used in security applications, e.g. for banknote printing. The aforementioned first and second states are provided by using a material that shows an increase in viscosity in reaction to an exposure to an electromagnetic radiation. That is, when the fluid binder material is cured or solidified, said binder material converts into the second state, where the non-spherical magnetic or magnetizable pigment particles are fixed in their current positions and orientations and can no longer move nor rotate within the binder material. As known to those skilled in the art, ingredients comprised in a radiation curable coating composition to be applied onto a surface such as a substrate and the physical properties of said radiation curable coating composition must fulfil the requirements of the process used to transfer the radiation curable coating composition to the substrate surface. Consequently, the binder material comprised in the radiation curable coating composition described herein is typically chosen among those known in the art and depends on the coating or printing process used to apply the radiation curable coating composition and the chosen radiation curing process.

[0052] In the optical effect layers (OELs) described herein, the non-spherical magnetic or magnetizable pigment particles described herein are dispersed in the at least partially cured radiation curable coating composition comprising an at least partially cured binder material that fixes / freezes the orientation of the magnetic or magnetizable pigment particles. The cured binder material is at least partially transparent to electromagnetic radiation of a range of wavelengths comprised between 200 nm and 2500 nm. The binder material is thus, at least in its cured or solid state (also referred to as second state herein), at least partially transparent to electromagnetic radiation of a range of wavelengths comprised between 200 nm and 2500 nm, i.e. within the wavelength range which is typically referred to as the “optical spectrum” and which comprises infrared, visible and UV portions of the electromagnetic spectrum, such that the particles comprised in the binder material in its cured or solid state and their orientation-dependent reflectivity can be perceived through the binder material. Preferably, the cured binder material is at least partially transparent to electromagnetic radiation of a range of wavelengths comprised between 200 nm and 800 nm, more preferably comprised betweenSICPA HOLDING SA 272 626 t8400 nm and 700 nm. Herein, the term “transparent” denotes that the transmission of electromagnetic radiation through a layer of 20 pm of the cured binder material as present in the OEL (not including the platelet-shaped magnetic or magnetizable pigment particles, but all other optional components of the OEL in case such components are present) is at least 50%, more preferably at least 60%, even more preferably at least 70%, at the wavelength(s) concerned. This can be determined for example by measuring the transmittance of a test piece of the cured binder material (not including the non-spherical magnetic or magnetizable pigment particles) in accordance with well- established test methods, e.g. DIN 5036-3 (1979-11). If the OEL serves as a covert security feature, then typically technical means will be necessary to detect the (complete) optical effect generated by the OEL under respective illuminating conditions comprising the selected non-visible wavelength; said detection requiring that the wavelength of incident radiation is selected outside the visible range, e.g. in the near UV-range. The infrared, visible and UV portions of the electromagnetic spectrum approximately correspond to the wavelength ranges between 700-2500 nm, 400-700 nm, and 200-400 nm respectively.

[0053] As mentioned hereabove, the radiation curable coating composition described herein depends on the coating or printing process used to apply said radiation curable coating composition and the chosen curing process. Preferably, curing of the radiation curable coating composition involves a chemical reaction which is not reversed by a simple temperature increase (e.g. up to 80°C) that may occur during a typical use of an article comprising the OEL described herein. The term “curing” or “curable” refers to processes including the chemical reaction, crosslinking or polymerization of at least one component in the applied radiation curable coating composition in such a manner that it turns into a polymeric material having a greater molecular weight than the starting substances. Radiation curing advantageously leads to an instantaneous increase in viscosity of the radiation curable coating composition after exposure to the curing irradiation, thus preventing any further movement of the pigment particles and in consequence any loss of information after the magnetic orientation step. Preferably, the at least partially curing step (step iii)) is carried out by radiation curing including UV-vis light radiation curing or by E-beam radiation curing, more preferably by UV-Vis light radiation curing.

[0054] Therefore, suitable radiation curable coating compositions for the present invention include radiation curable compositions that may be cured by UV-visible light radiation (hereafter referred as UV-Vis light radiation) or by E-beam radiation (hereafter referred as EB radiation). Radiation curable compositions are known in the art and can be found in standard textbooks such as the series "Chemistry & Technology of UV & EB Formulation for Coatings, Inks & Paints", Volume IV, Formulation, by C. Lowe, G. Webster, S. Kessel and I. McDonald, 1996 by John Wiley & Sons in association with SITA Technology Limited. According to one particularly preferred embodiment of the present invention, the radiation curable coating composition described herein is a UV-Vis radiation curable coating composition. Therefore, a radiation curable coating composition comprising non-spherical magnetic or magnetizable pigment particles described herein is preferably at least partially cured by UV-Vis light radiation, preferably by narrow-bandwidth LED light in the UV-A (315-400 nm) or blue (400-500 nm) spectral region, most preferable by a high-power LED source emitting in the 350 nm to 450 nm spectral region, with a typical emission bandwidth in the 20 nm to 50 nm range. UV radiation from mercury vaporSICPA HOLDING SA 272 626 t8 lamps or doped mercury lamps can also be used to increase the curing rate of the radiation curable coating composition.

[0055] Preferably, the UV-Vis radiation curable coating composition comprises one or more compounds selected from the group consisting of radically curable compounds and cationically curable compounds.

[0056] The UV-Vis radiation curable coating composition described herein may be a hybrid system and comprise a mixture of one or more cationically curable compounds and one or more radically curable compounds. Cationically curable compounds are cured by cationic mechanisms typically including the activation by radiation of one or more photoinitiators which liberate cationic species, such as acids, which in turn initiate the curing so as to react and / or cross-link the monomers and / or oligomers to thereby cure the radiation curable coating composition. Radically curable compounds are cured by free radical mechanisms typically including the activation by radiation of one or more photoinitiators, thereby generating radicals which in turn initiate the polymerization so as to cure the radiation curable coating composition. Depending on the monomers, oligomers or prepolymers used to prepare the binder comprised in the UV-Vis radiation curable coating compositions described herein, different photoinitiators might be used. Suitable examples of free radical photoinitiators are known to those skilled in the art and include without limitation acetophenones, benzophenones, benzyldimethyl ketals, alpha-aminoketones, alpha-hydroxyketones, phosphine oxides and phosphine oxide derivatives, as well as mixtures of two or more thereof. Suitable examples of cationic photoinitiators are known to those skilled in the art and include without limitation onium salts such as organic iodonium salts (e.g. diaryl iodoinium salts), oxonium (e.g. triaryloxonium salts) and sulfonium salts (e.g. triarylsulphonium salts), as well as mixtures of two or more thereof. Other examples of useful photoinitiators can be found in standard textbooks such as "Chemistry & Technology of UV & EB Formulation for Coatings, Inks & Paints", Volume III, "Photoinitiators for Free Radical Cationic and Anionic Polymerization", 2nd edition, by J. V. Crivello & K. Dietliker, edited by G. Bradley and published in 1998 by John Wiley & Sons in association with SITA Technology Limited. It may also be advantageous to include a sensitizer in conjunction with the one or more photoinitiators in order to achieve efficient curing. Typical examples of suitable photosensitizers include without limitation isopropyl-thioxanthone (ITX), 1-chloro-2-propoxy- thioxanthone (CPTX), 2- chloro-thioxanthone (CTX) and 2,4-diethyl-thioxanthone (DETX) and mixtures of two or more thereof. The one or more photoinitiators comprised in the UV-Vis radiation curable coating compositions are preferably present in a total amount from about 0.1 wt-% to about 20 wt-%, more preferably about 1 wt-% to about 15 wt-%, the weight percents being based on the total weight of the UV-Vis radiation curable coating compositions.

[0057] The radiation curable coating composition described herein may further comprise one or more marker substances ortaggants and / or one or more machine readable materials selected from the group consisting of magnetic materials (different from the platelet-shaped magnetic or magnetizable pigment particles described herein), luminescent materials, electrically conductive materials and infrared absorbing materials. As used herein, the term “machine readable material” refers to a material which can be comprised in a layer so as to confer a way to authenticate said layer or article comprising said layer by the use of a particular equipment for its authentication.SICPA HOLDING SA 272 626 t8

[0058] The radiation curable coating composition described herein may further comprise one or more coloring components selected from the group consisting of organic pigment particles, inorganic pigment particles, and organic dyes, and / or one or more additives. The latter include without limitation compounds and materials that are used for adjusting physical, rheological and chemical parameters of the radiation curable coating composition such as the viscosity (e.g. solvents, thickeners and surfactants), the consistency (e.g. anti-settling agents, fillers and plasticizers), the foaming properties (e.g. antifoaming agents), the lubricating properties (waxes, oils), UV stability (photostabilizers), the adhesion properties, the antistatic properties, the shelf life (polymerization inhibitors), the gloss etc. Additives described herein may be present in the radiation curable coating composition in amounts and in forms known in the art, including so-called nano-materials where at least one of the dimensions of the additive is in the range of 1 to 1000 nm.

[0059] The radiation curable coating composition described herein comprises the non-spherical magnetic or magnetizable pigment particles described herein. Preferably, the non-spherical magnetic or magnetizable pigment particles are present in an amount from about 2 wt-% to about 40 wt-%, more preferably about 4 wt-% to about 30 wt-%, the weight percents being based on the total weight of the radiation curable coating composition comprising the binder material, the non-spherical magnetic or magnetizable pigment particles and other optional components of the radiation curable coating composition.

[0060] The non-spherical magnetic or magnetizable pigment particles are preferably prolate or oblate ellipsoid-shaped, platelet-shaped or needle-shaped particles or a mixture of two or more thereof and more preferably platelet-shaped particles. Non-spherical magnetic or magnetizable pigment particles described herein are defined as having, due to their non-spherical shape, non-isotropic reflectivity with respect to an incident electromagnetic radiation for which the cured or hardened binder material is at least partially transparent. As used herein, the term “non-isotropic reflectivity” denotes that the proportion of incident radiation from a first angle that is reflected by a particle into a certain (viewing) direction (a second angle) is a function of the orientation of the particles, i.e. that a change of the orientation of the particle with respect to the first angle can lead to a different magnitude of the reflection to the viewing direction. Preferably, the non- spherical magnetic or magnetizable pigment particles described herein have a non-isotropic reflectivity with respect to incident electromagnetic radiation in some parts or in the complete wavelength range of from about 200 to about 2500 nm, more preferably from about 400 to about 700 nm, such that a change of the particle’s orientation results in a change of reflection by that particle into a certain direction. As known by the man skilled in the art, the magnetic or magnetizable pigment particles described herein are different from conventional pigment particles, in that said conventional pigment particles exhibit the same color and reflectivity, independent of the particle orientation, whereas the magnetic or magnetizable pigment particles described herein exhibit either a reflection or a color, or both, that depend on the particle orientation. The non-spherical magnetic or magnetizable pigment particles described herein are preferably platelet-shaped magnetic or magnetizable pigment particles.

[0061] The process for producing the optical effect layer (OEL) described herein may further comprise, for embodiments with platelet-shaped magnetic or magnetizable pigment particles, prior to or at leastSICPA HOLDING SA 272 626 t8 partially simultaneously with step ii) a step of exposing the coating layer (110) to a dynamic magnetic field of a device so as to bi-axially orient at least a part of the platelet-shaped magnetic or magnetizable pigment particles, said step being carried out prior to or partially simultaneously with step ii) and before step iii).

[0062] In contrast to needle-shaped pigment particles which can be considered as one-dimensional particles, platelet-shaped pigment particles have an X-axis and a Y-axis defining a plane of predominant extension of the particles. In other words, platelet-shaped pigment particles may be considered to be two-dimensional particles due to the large aspect ratio of their dimensions. A platelet-shaped pigment particle can be considered as a two-dimensional structure wherein the dimensions X and Y are substantially larger than dimension Z. Platelet-shaped pigment particles are also referred in the art as oblate particles or flakes. Such pigment particles may be described with a main axis X corresponding to the longest dimension crossing the pigment particle and a second axis Y perpendicular to X which also lies within said pigment particles. Carrying out a bi-axial orientation leads to platelet-shaped magnetic or magnetizable pigment particles having two main axes constrained; i.e. bi-axially oriented neighboring platelet-shaped magnetic pigment particles are close to each other in space and are substantially parallel to each other. Put another way, bi-axial orientation aligns the planes of the plateletshaped magnetic or magnetizable pigment particles so that the planes of said pigment particles are oriented to be substantially parallel relative to the planes of neighboring (in all directions) plateletshaped magnetic or magnetizable pigment particles. Preferably, the bi-axial orientation of the plateletshaped magnetic or magnetizable pigment particles described herein allows the platelet-shaped magnetic or magnetizable pigment particles to form a sheet-like structure with their X and Y axes substantially parallel to the substrate (120) surface and are planarized in said two dimensions or have a first axis within the X-Y plane substantially parallel to the substrate (120) surface and a second axis being substantially perpendicular to said first axis at a substantially non-zero elevation angle to the substrate (120) surface or have their X-Y plane substantially parallel to an imaginary spheroid surface.

[0063] Processes comprising such a step of exposing the radiation curable coating composition to a dynamic magnetic field of a device so as to bi-axially orient at least a part of the platelet-shaped magnetic or magnetizable pigment particles prior to the step ii) described herein are disclosed in WO 2015 / 086257 A1. As described hereabove, carrying out a bi-axial orientation means that plateletshaped magnetic or magnetizable pigment particles are made to orientate in such a way that their two main axes are constrained. That is, each platelet-shaped magnetic or magnetizable pigment particle can be considered to have a major axis in the plane of the pigment particle and an orthogonal minor axis in the plane of the pigment particle. The major and minor axes of the platelet-shaped magnetic or magnetizable pigment particles are each caused to orient according to the dynamic magnetic field. Effectively, this results in neighboring the magnetic or magnetizable particles magnetic or magnetizable pigment particles that are close to each other in space to be substantially parallel to each other. In order to perform a bi-axial orientation, the magnetic or magnetizable particles magnetic or magnetizable pigment particles must be subjected to a strongly time-dependent external magnetic field.

[0064] For embodiments wherein the magnetic device (100) or the magnetic apparatus (1000) described herein comprises the engraved plate (160) being an engraved soft magnetic plate (160)SICPA HOLDING SA 272 626 t8 described herein, the magnetic orientation of at least a part of the non-spherical magnetic or magnetizable pigment particles (step ii)) being platelet-shaped magnetic or magnetizable pigment particles described herein may be carried out by forming an assembly of the substrate (120) carrying the coating layer (110) above the magnetic device (100) or the magnetic apparatus (1000), wherein said assembly is moved through an inhomogeneous magnetic field of a static device so as to bi-axially orient at least a part of the platelet-shaped magnetic or magnetizable pigment particles as described in WO 2018 / 019594 A1 , WO 2018 / 033512 A1 and in the co-pending application PCT / EP2024 / 058266.

[0065] Particularly preferred devices for bi-axially orienting the magnetic or magnetizable particles magnetic or magnetizable pigment particles are disclosed in EP 2 157 141 A1 . The device disclosed in EP 2 157 141 A1 provides a dynamic magnetic field that changes its direction forcing the magnetic or magnetizable particles magnetic or magnetizable pigment particles to rapidly oscillate until both main axes, X-axis and Y-axis, become substantially parallel to the substrate surface, i.e. the magnetic or magnetizable particles magnetic or magnetizable pigment particles rotate until they come to the stable sheet-like formation with their X and Y axes substantially parallel to the substrate surface and are planarized in said two dimensions. Other particularly preferred devices for bi-axially orienting the magnetic or magnetizable particles magnetic or magnetizable pigment particles comprise linear permanent magnet Halbach arrays, i.e. assemblies comprising a plurality of magnets with different magnetization directions. Detailed description of Halbach permanent magnets was given by Z.Q. Zhu and D. Howe (Halbach permanent magnet machines and applications: a review, IEE. Proc. Electric Power Appl., 2001 , 148, p. 299-308). The magnetic field produced by such a Halbach array has the properties that it is concentrated on one side while being weakened almost to zero on the other side. WO 2016 / 083259 A1 discloses suitable devices for bi-axially orienting magnetic or magnetizable particles magnetic or magnetizable pigment particles, wherein said devices comprise a Halbach cylinder assembly.

[0066] Other particularly preferred devices for bi-axially orienting the magnetic or magnetizable particles magnetic or magnetizable pigment particles are spinning magnets, said magnets comprising disc-shaped spinning magnets or magnetic assemblies that are essentially magnetized along their diameter. Suitable spinning magnets or magnetic assemblies are described in US 2007 / 0172261 A1 , said spinning magnets or magnetic assemblies generate radially symmetrical time-variable magnetic fields, allowing the bi-orientation of magnetic or magnetizable particles magnetic or magnetizable pigment particles of a not yet cured or hardened coating composition. These magnets or magnetic assemblies are driven by a shaft (or spindle) connected to an external motor. CN 102529326 B discloses examples of devices comprising spinning magnets that might be suitable for bi-axially orienting magnetic or magnetizable particles magnetic or magnetizable pigment particles. In a preferred embodiment, suitable devices for bi-axially orienting magnetic or magnetizable particles magnetic or magnetizable pigment particles are shaft-free disc-shaped spinning magnets or magnetic assemblies constrained in a housing made of non-magnetic, preferably non-conducting, materials and are driven by one or more magnet-wire coils wound around the housing. Examples of such shaft-free disc-shaped spinning magnets or magnetic assemblies are disclosed in WO 2015 / 082344 A1 , WO 2016 / 026896 A1 and in WO 2018 / 141547 A1 .SICPA HOLDING SA 272 626 t8

[0067] Suitable examples of non-spherical magnetic or magnetizable pigment particles described herein include without limitation pigment particles comprising a magnetic metal selected from the group consisting of cobalt (Co), iron (Fe), gadolinium (Gd) and nickel (Ni); magnetic alloys of iron, chromium, manganese, cobalt, nickel and mixtures of two or more thereof; magnetic oxides of chromium, manganese, cobalt, iron, nickel and mixtures of two or more thereof; and mixtures of two or more thereof. The term “magnetic” in reference to the metals, alloys and oxides is directed to ferromagnetic or ferrimagnetic metals, alloys and oxides. Magnetic oxides of chromium, manganese, cobalt, iron, nickel or a mixture of two or more thereof may be pure or mixed oxides. Examples of magnetic oxides include without limitation iron oxides such as hematite (Fe2O3), magnetite (Fe3O4), chromium dioxide (CrO2), magnetic ferrites (MFe2O4), magnetic spinels (MR2O4), magnetic hexaferrites (MFe12O19), magnetic orthoferrites (RFeO3), magnetic garnets M3R2(AO4)3, wherein M stands for two-valent metal, R stands for three-valent metal, and A stands for four-valent metal.

[0068] Examples of non-spherical magnetic or magnetizable pigment particles described herein include without limitation pigment particles comprising a magnetic layer M made from one or more of a magnetic metal such as cobalt (Co), iron (Fe), gadolinium (Gd) or nickel (Ni); and / or a magnetic alloy of iron, chromium, cobalt or nickel, wherein said magnetic or magnetizable pigment particles may be multilayered structures comprising one or more additional layers. Preferably, the one or more additional layers are layers A independently made from one or more materials selected from the group consisting of metal fluorides such as magnesium fluoride (MgF2), aluminum fluoride (AIF3), cerium fluoride (CeF3), lanthanum fluoride (LaF3), sodium aluminum fluorides (e.g. Na3AIF6), neodymium fluoride (NdF3), samarium fluoride (SmF3), barium fluoride (BaF2), calcium fluoride (CaF2), lithium fluoride (LiF), preferably the metal fluoride is magnesium fluoride (MgF2); oxides such as silicon oxide (SiO), silicon dioxide (SiO2), titanium oxides (TiO2), zinc sulphide (ZnS) and aluminum oxide (AI2O3), preferably silicon dioxide (SiO2); or layers B independently made from one or more materials selected from the group consisting of metals and metal alloys, preferably selected from the group consisting of reflective metals and reflective metal alloys, and more preferably selected from the group consisting of aluminum (Al), silver (Ag), copper (Cu), gold (Au), platinum (Pt), tin (Sn), titanium (Ti), palladium (Pd), rhodium (Rh), niobium (Nb), chromium (Cr), nickel (Ni), and alloys thereof, still more preferably selected from the group consisting of aluminum (Al), chromium (Cr), nickel (Ni) and alloys thereof, and even more preferably aluminum (Al); or a combination of one or more layers A such as those described hereabove and one or more layers B such as those described hereabove. Typical examples of the platelet-shaped magnetic or magnetizable pigment particles being multilayered structures described hereabove include without limitation A / M multilayer structures, A / M / A multilayer structures, A / M / B multilayer structures, A / B / M / A multilayer structures, A / B / M / B multilayer structures, A / B / M / B / A multilayer structures, B / M multilayer structures, B / M / B multilayer structures, B / A / M / A multilayer structures, B / A / M / B multilayer structures, B / A / M / B / A / multilayer structures, wherein the layers A, the magnetic layers M and the layers B are chosen from those described hereabove.

[0069] According to one embodiment, at least a part of the non-spherical magnetic or magnetizable pigment particles described herein are dielectric / reflector / magnetic / reflector / dielectric multilayer structures, wherein the reflector layers described herein are independently and preferably made fromSICPA HOLDING SA 272 626 t8 one or more selected from the group consisting of metals and metal alloys, preferably selected from the group consisting of aluminum (Al), silver (Ag), copper (Cu), gold (Au), platinum (Pt), tin (Sn), titanium (Ti), palladium (Pd), rhodium (Rh), niobium (Nb), chromium (Cr), nickel (Ni), and alloys thereof, even more preferably selected from the group consisting of aluminum (Al), chromium (Cr), nickel (Ni) and alloys thereof and more preferably aluminum (Al), wherein the dielectric layers are independently and preferably made from one or more materials selected from the group consisting of metal fluorides such as magnesium fluoride (MgF2), aluminum fluoride (AIF3), cerium fluoride (CeF3), lanthanum fluoride (LaF3), sodium aluminum fluorides (e.g. Na3AIF6), neodymium fluoride (NdF3), samarium fluoride (SmF3), barium fluoride (BaF2), calcium fluoride (CaF2), lithium fluoride (LiF), preferably the metal fluoride is magnesium fluoride (MgF2); oxides such as silicon oxide (SiO), silicon dioxide (SiO2), titanium oxides (TiO2), zinc sulphide (ZnS) and aluminum oxide (AI2O3), preferably silicon dioxide (SiO2); and wherein the magnetic layer is preferably made from one or more of a magnetic metal such as cobalt (Co), iron (Fe), gadolinium (Gd) or nickel (Ni); and / or a magnetic alloy of iron, chromium, cobalt or nickel. Alternatively, the dielectric / reflector / magnetic / reflector / dielectric / multilayer structures described herein may be multilayer pigment particles being considered as safe for human health and the environment, wherein said magnetic layer comprises a magnetic alloy having a substantially nickel- free composition including 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.

[0070] At least part of the non-spherical magnetic or magnetizable pigment particles described herein may be constituted by non-spherical colorshifting magnetic or magnetizable pigment particles and / or non- spherical magnetic or magnetizable pigment particles having no colorshifting properties. Preferably, at least a part of the non-spherical magnetic or magnetizable pigment particles described herein is constituted by non-spherical colorshifting magnetic or magnetizable pigment particles. In addition to the overt security provided by the colorshifting property of non-spherical colorshifting magnetic or magnetizable pigment particles, which allows easily detecting, recognizing and / or discriminating an article or security document or article carrying a radiation curable coating composition, coating or layer comprising the non-spherical colorshifting magnetic or magnetizable pigment particles described herein from their possible counterfeits using the unaided human senses, the optical properties of the non-spherical colorshifting magnetic or magnetizable pigment particles may also be used as a machine readable tool for the recognition of the optical effect layer (OEL). Thus, the optical properties of the non-spherical colorshifting magnetic or magnetizable pigment particles may simultaneously be used as a covert or semi-covert security feature in an authentication process wherein the optical (e.g. spectral) properties of the pigment particles are analyzed. The use of non-spherical colorshifting magnetic or magnetizable pigment particles in radiation curable coating compositions for producing an OEL enhances the significance of the OEL as a security feature in security document applications, because such materials (i.e. non-spherical colorshifting magnetic or magnetizable pigment particles) are reserved to the security document printing industry and are not commercially available to the public.

[0071] Moreover, and due to their magnetic characteristics, the non-spherical magnetic or magnetizable pigment particles described herein are machine readable, and therefore radiation curableSICPA HOLDING SA 272 626 t8 coating compositions comprising those pigment particles may be detected for example with specific magnetic detectors. Radiation curable coating compositions comprising the non-spherical magnetic or magnetizable pigment particles described herein may therefore be used as a covert or semi-covert security element (authentication tool) for security documents.

[0072] As mentioned above, preferably at least a part of the non-spherical magnetic or magnetizable pigment particles is constituted by non-spherical colorshifting magnetic or magnetizable pigment particles. These can more preferably be selected from the group consisting of non-spherical magnetic thin-film interference pigment particles, non-spherical magnetic cholesteric liquid crystal pigment particles, non-spherical interference coated pigment particles comprising a magnetic material and mixtures of two or more thereof.

[0073] Magnetic thin film interference pigment particles are known to those skilled in the art and are disclosed e.g. 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 A1 and in the documents cited 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.

[0074] Preferred five-layer Fabry-Perot multilayer structures consist of absorber / dielectric / reflector / dielectric / absorber multilayer structures wherein the reflector and / or the absorber is also a magnetic layer, preferably the reflector and / or the absorber is a magnetic layer comprising nickel, iron and / or cobalt, and / or a magnetic alloy comprising nickel, iron and / or cobalt and / or a magnetic oxide comprising nickel (Ni), iron (Fe) and / or cobalt (Co). Preferred six-layer Fabry- Perot multilayer structures consist of absorber / dielectric / reflector / magnetic / dielectric / absorber multilayer structures. Preferred seven-layer Fabry Perot multilayer structures consist of absorber / dielectric / reflector / magnetic / reflector / dielectric / absorber multilayer structures such as disclosed in US 4,838,648. Preferred nine-layer Fabry-Perot multilayer structures consist of dielec- tric / absorber / dielectric / reflector / magnetic / dielectric / absorber / dielectric multilayer structures. Preferred eleven-layer Fabry-Perot multilayer structures consist of absorb- er / dielectric / absorber / dielectric / reflector / magnetic / reflector / dielectric / absorber / dielectric / absorber multilayer structures.

[0075] Preferably, the reflector layers described herein are independently made from one or more materials selected from the group consisting of metals and metal alloys, preferably selected from the group consisting of reflective metals and reflective metal alloys, more preferably selected from the group consisting of aluminum (Al), silver (Ag), copper (Cu), gold (Au), platinum (Pt), tin (Sn), titanium (Ti), palladium (Pd), rhodium (Rh), niobium (Nb), chromium (Cr), nickel (Ni), and alloys thereof, even more preferably selected from the group consisting of aluminum (Al), chromium (Cr), nickel (Ni) and alloys thereof, and still more preferably aluminum (Al). Preferably, the dielectric layers are independently made from one or more materials selected from the group consisting of metal fluorides such as magnesium fluoride (MgF2), aluminum fluoride (AIF3), cerium fluoride (CeF3), lanthanum fluoride (LaF3), sodium aluminum fluorides (e.g. Na3AIF6), neodymium fluoride (NdF3), samarium fluoride (SmF3), barium fluoride (BaF2), calcium fluoride (CaF2), lithium fluoride (LiF), and metal oxides such as silicon oxideSICPA HOLDING SA 272 626 t8(SiO), silicon dioxide (SiO2), titanium oxide (TiO2), aluminum oxide (AI2O3), more preferably selected from the group consisting of magnesium fluoride (MgF2) and silicon dioxide (SiO2) and still more preferably magnesium fluoride (MgF2). Preferably, the absorber layers are independently made from one or more materials selected from the group consisting of aluminum (Al), silver (Ag), copper (Cu), palladium (Pd), platinum (Pt), titanium (Ti), vanadium (V), iron (Fe) tin (Sn), tungsten (W), molybdenum (Mo), rhodium (Rh), Niobium (Nb), chromium (Cr), nickel (Ni), metal oxides thereof, metal sulfides thereof, metal carbides thereof, and metal alloys thereof, more preferably selected from the group consisting of chromium (Cr), nickel (Ni), iron (Fe), metal oxides thereof, and metal alloys thereof, and still more preferably selected from the group consisting of chromium (Cr), nickel (Ni), and metal alloys thereof. Preferably, the magnetic layer comprises nickel (Ni), iron (Fe) and / or cobalt (Co); and / or a magnetic alloy comprising nickel (Ni), iron (Fe) and / or cobalt (Co); and / or a magnetic oxide comprising nickel (Ni), iron (Fe) and / or cobalt (Co). When magnetic thin film interference pigment particles comprising a seven-layer Fabry-Perot structure are preferred, it is particularly preferred that the magnetic thin film interference pigment particles comprise a seven-layer Fabry-Perot absorber / dielectric / reflector / magnetic / reflector / dielectric / absorber multilayer structure consisting of a Cr / MgF2 / AI / M / AI / MgF2 / Cr multilayer structure, wherein M a magnetic layer comprising 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).

[0076] The magnetic thin film interference pigment particles described herein may be multilayer pigment particles being considered as safe for human health and the environment and being based for example on five-layer Fabry-Perot multilayer structures, six-layer Fabry-Perot multilayer structures, seven-layer Fabry-Perot multilayer structures, nine-layer Fabry-Perot multilayer structures and elevenlayer Fabry-Perot multilayer structures, wherein said pigment particles include one or more magnetic layers comprising a magnetic alloy having a substantially nickel-free composition including 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 being considered as safe for human health and the environment can be found in EP 2 402 401 A1 which is hereby incorporated by reference in its entirety.

[0077] Magnetic thin film interference pigment particles described herein are typically manufactured by an established deposition technique for the different required layers onto a web. After deposition of the desired number of layers, e.g. by physical vapor deposition (PVD), chemical vapor deposition (CVD) or electrolytic deposition, the stack of layers is removed from the web, either by dissolving a release layer in a suitable solvent, or by stripping the material from the web. The so-obtained material is then broken down to platelet-shaped pigment particles which have to be further processed by grinding, milling (such as for example jet milling processes) or any suitable method so as to obtain pigment particles of the required size. The resulting product consists of flat platelet-shaped pigment particles with broken edges, irregular shapes and different aspect ratios. Further information on the preparation of suitable platelet-shaped magnetic thin film interference pigment particles can be found e.g. in EP 1 710 756 A1 and EP 1 666 546 A1 which are hereby incorporated by reference.SICPA HOLDING SA 272 626 t8

[0078] Suitable magnetic cholesteric liquid crystal pigment particles exhibiting colorshifting characteristics include without limitation magnetic monolayered cholesteric liquid crystal pigment particles and magnetic multilayered cholesteric liquid crystal pigment particles. Such pigment particles are disclosed for example in WO 2006 / 063926 A1 , US 6,582,781 and US 6,531 ,221 . WO 2006 / 063926 A1 discloses monolayers and pigment particles obtained therefrom with high brilliance and colorshifting properties with additional particular properties such as magnetizability. The disclosed monolayers and pigment particles, which are obtained therefrom by comminuting said monolayers, include a three- dimensionally crosslinked cholesteric liquid crystal mixture and magnetic nanoparticles. US 6,582,781 and US 6,410,130 disclose cholesteric multilayer pigment particles which comprise the sequence A1 / B / A2, wherein A1 and A2 may be identical or different and each comprises at least one cholesteric layer, and B is an interlayer absorbing all or some of the light transmitted by the layers A1 and A2 and imparting magnetic properties to said interlayer. US 6,531 ,221 discloses platelet-shaped cholesteric multilayer pigment particles which comprise the sequence A / B and optionally C, wherein A and C are absorbing layers comprising pigment particles imparting magnetic properties, and B is a cholesteric layer.

[0079] Suitable interference coated pigment particles comprising one or more magnetic materials include without limitation structures consisting of a substrate selected from the group consisting of a core coated with one or more layers, wherein at least one of the core or the one or more layers have magnetic properties. For example, suitable interference coated pigment particles comprise a core made of a magnetic material such as those described hereabove, said core being coated with one or more layers made of one or more metal oxides, or they have a structure consisting of a core made of synthetic or natural micas, layered silicates (e.g. talc, kaolin and sericite), glasses (e.g. borosilicates), silicon dioxides (SiO2), aluminum oxides (AI2O3), titanium oxides (TiO2), graphites and mixtures of two or more thereof. Furthermore, one or more additional layers such as coloring layers may be present.

[0080] The platelet-shaped magnetic or magnetizable pigment particles described herein preferably have a size d50 between about 2 |j.m and about 50 |j.m (as measured by direct optical granulometry).

[0081] The non-spherical magnetic or magnetizable pigment particles described herein may be surface treated so at to protect them against any deterioration that may occur in the radiation curable coating composition and / or to facilitate their incorporation in the radiation curable coating composition; typically corrosion inhibitor materials and / or wetting agents may be used.

[0082] The substrate (120) described herein is preferably selected from the group consisting of papers or other fibrous materials, such as cellulose, paper-comprising materials, glasses, metals, ceramics, plastics and polymers, metalized plastics or polymers, composite materials and mixtures or combinations thereof. Typical paper, paper-like or other fibrous materials are made from a variety of fibers including without limitation abaca, cotton, linen, wood pulp, and blends thereof. As is well known to those skilled in the art, cotton and cotton / linen blends are preferred for banknotes, while wood pulp is commonly used in non-banknote security documents. Typical examples of plastics and polymers include polyolefins such as polyethylene (PE) and polypropylene (PP), polyamides, polyesters such as polyethylene terephthalate) (PET), poly(1 ,4-butylene terephthalate) (PBT), poly(ethylene 2,6- naphthoate) (PEN) and polyvinylchlorides (PVC). Spunbond olefin fibers such as those sold under theSICPA HOLDING SA 272 626 t8 trademark Tyvek® may also be used as substrate. Typical examples of metalized plastics or polymers include the plastic or polymer materials described hereabove having a metal arranged continuously or discontinuously on their surface. Typical example of metals include without limitation aluminum (Al), chromium (Cr), copper (Cu), gold (Au), iron (Fe), nickel (Ni), silver (Ag), combinations thereof or alloys of two or more of the aforementioned metals. The metallization of the plastic or polymer materials described hereabove may be done by an electrodeposition process, a high-vacuum coating process or by a sputtering process. Typical examples of composite materials include without limitation multilayer structures or laminates of paper and at least one plastic or polymer material such as those described hereabove as well as plastic and / or polymer fibers incorporated in a paper-like or fibrous material such as those described hereabove. The substrate (120) can comprise further additives that are known to the skilled person, such as sizing agents, Whiteners, processing aids, reinforcing or wet strengthening agents, etc. The substrate (120) described herein may be provided under the form of a web (e.g. a continuous sheet of the materials described hereabove) or under the form of sheets. Should the optical effect layer (OEL) produced according to the process described herein be on a security document or article, and with the aim of further increasing the security level and the resistance against counterfeiting and illegal reproduction of said security document or article, the substrate (120) may comprise printed, coated, or laser-marked or laser-perforated indicia, watermarks, holograms, microlenses, micromirrors, security threads, fibers, planchettes, luminescent compounds, windows, foils, decals and combinations of two or more thereof. With the same aim of further increasing the security level and the resistance against counterfeiting and illegal reproduction of security documents, the substrate may comprise one or more marker substances or taggants and / or machine readable substances (e.g. luminescent substances, UV / visible / IR absorbing substances, magnetic substances and combinations thereof).

[0083] The magnetic apparatuses (1000) schematically illustrated in Figs 1A-C comprise the magnetic device (100) (said device (100) comprising the magnetic assembly (130), the magnetic-field generating device (140) and the pole piece (150); the holding case (170); and the holding case bottom lid (171) described herein, wherein the holding case (170) comprises a cavity for receiving the magnetic device (100) described herein. According to one embodiment shown for example in Figs 1A-C and 1 H, the magnetic-field generating device (140) is arranged on top ofthe magnetic assembly (130), the magnetic assembly (130) is arranged on top of the pole piece (150), and the holding case (170) is arranged on top of the magnetic-field generating device (140); for embodiments comprising the optional engraved plate (160), said engraved plate (160) is arranged on top of the holding case (170). According to one embodiment shown for example in Figs 1 D-G, the magnetic assembly (130) is arranged on top of the magnetic-field generating device (140), the magnetic-field generating device (140) is arranged on top of the pole piece (150), and the holding case (170) is arranged on top of the magnetic assembly (130); for embodiments comprising the optional engraved plate (160), said engraved plate (160) is arranged on top ofthe holding case (170). Preferably, the magnetic assembly (130), the magnetic-field generating device (140), the pole piece (150), the holding case (170) and the holding case bottom lid (171) are essentially centered with respect to one another.

[0084] The distance between the lowermost surface of the substrate (120) facing the magnetic device (100) or the magnetic apparatus (1000) and the uppermost surface of the uppermost element beingSICPA HOLDING SA 272 626 t8 either the magnetic-field generating device (140) (distance h in Fig. 1A for embodiments wherein the magnetic-field generating device (140) is arranged on top of the magnetic assembly (130)) or the magnetic assembly (130)(distance h in Fig. 1 D, for the embodiments wherein the magnetic assembly (130) is arranged on top of the magnetic-field generating device (140)) is preferably between about 0 mm and about 10 mm, more preferably between about 0 mm and about 5 mm.

[0085] Figs 1A-G schematically illustrate suitable magnetic apparatuses (1000) comprising magnetic devices (100) and Fig. 2-5 schematically illustrate suitable magnetic assemblies (130) of the magnetic devices (100) described herein to be used during the process described herein for producing the optical effect layers (OELs) described herein.

[0086] The magnetic assembly (130) of the magnetic device (100) described herein comprises the non-magnetic supporting matrix (135) described herein. The non-magnetic supporting matrix (135) of the magnetic assembly (130) is made of one or more non-magnetic materials. The non-magnetic materials are preferably selected from the group consisting of low conducting materials, non-conducting materials and mixtures thereof, such as for example engineering plastics and polymers, aluminium, aluminium alloys, titanium, titanium alloys and austenitic steels (i.e. non-magnetic steels). Engineering plastics and polymers include without limitation polyaryletherketones (PAEK) and its derivatives polyetheretherketones (PEEK), polyetherketoneketones (PEKK), polyetheretherketoneketones (PEEKK) and polyetherketoneetherketoneketone (PEKEKK); polyacetals, polyamides, polyesters, polyethers, copolyetheresters, polyimides, polyetherimides, high-density polyethylene (HDPE), ultra- high molecular weight polyethylene (UHMWPE), polybutylene terephthalate (PBT), polypropylene, acrylonitrile butadiene styrene (ABS) copolymer, fluorinated and perfluorinated polyethylenes, polystyrenes, polycarbonates, polyphenylenesulfide (PPS) and liquid crystal polymers. Preferred materials are PEEK (polyetheretherketone), POM (polyoxymethylene), PTFE (polytetrafluoroethylene), Nylon® (polyamide) and PPS. The non-magnetic supporting matrix (135) comprise indentations for receiving the first first bar dipole magnets (131 a and 131 b), the second first bar dipole magnet (131 a’ and 131 b’), the second dipole magnets (132a and 132b), the optional first and second third bar dipole magnets (133a and 133b) and the optional fourth bar dipole magnet (134) described herein.

[0087] The magnetic assembly (130) of the magnetic device (100) described herein comprises the first set S1 and the second set S2 at least partially embedded in the non-magnetic supporting matrix (135).

[0088] The magnetic assembly (130) of the magnetic device (100) described herein may further comprises a third set S3, a fourth set S4, ... , a nth set Sn, wherein said sets are at least partially embedded in the non-magnetic supporting matrix (135), preferably embedded so as to be flush with the non-magnetic supporting matrix (135) surface.

[0089] The first set S1 and the second set S2 each comprises a1) the pair of first bar dipole magnets (131 a, 131 a’; 131 b, 131 b’) described herein and the second dipole magnets (132a; 132b) described herein. The third set S3, the fourth set S4 and the nth set Sn each comprises a1) the pair of first bar dipole magnets (131 c, 131 c’; 131d, 131d’; 131 n, 131 n’) described herein and the second dipole magnets (132c; 132d, 132n, respectively) described herein.

[0090] Each pair of first bar dipole magnets independently comprises the first first bar dipole magnet (131 a; 131 b) and the second first bar dipole magnet (131 a’; 131 b’) having their magnetic axisSICPA HOLDING SA 272 626 t8 substantially parallel to the first plane and to the substrate (120) surface during the process described herein and having an opposite magnetic direction; i.e. the first first bar dipole magnet (131 a) of the first set S1 and the second first bar dipole magnet (131 a’) of the first set S1 have an opposite magnetic direction; the first first bar dipole magnet (131 b) of the second set S2 and the second first bar dipole magnet (131 b’) of the second set S2 have an opposite magnetic direction; the first first bar dipole magnet (131 a) of the first set S1 and the first first bar dipole magnet (131 b) of the second set S2 have an opposite magnetic direction; and the second first bar dipole magnet (131 a’) of the first set S1 and the second first bar dipole magnet (131 b’) of the second set S2 have an opposite magnetic direction.

[0091] The first first bar dipole magnet (131 a) and the second first bar dipole magnet (131 a’) of the first set S1 may have the same shape as or may have a different shape from, preferably have the same shape as, the second first bar dipole magnet (131 b) and the second first bar dipole magnet (131 b’) of the second set S2. The same apply for a third set S3, a fourth set S4 and a nth set Sn. The first first bar dipole magnet (131 a) and the second first bar dipole magnet (131 a’) of the first set S1 may be made from the same material as or may be made from a different material from, preferably are made from the same material as, the first first bar dipole magnet (131 b) and the second first bar dipole magnet (131 b’) of the second set S2. The same apply for a third set S3, a fourth set S4 and a nth set Sn.

[0092] The first first bar dipole magnets (131 a; 131 b) of the first set S1 and of the second set S2 are both arranged on a side of a virtual quadrangle (see “Q” as dotted virtual rectangles in Figs 2A, 3A, 4A and 5A) and the second first bar dipole magnets (131 a’; 131 b’) of the first set S1 and of the second set S2 are arranged on the opposite side of the virtual quadrangle. The first first bar dipole magnet (131 c) of the third set S3 is arranged on the side of the virtual quadrangle carrying the first first bar dipole magnets (131 a; 131 b) of the first set S1 and of the second set S2, and the second first bar dipole magnets (131 c’) of the third set S3 is arranged on the opposite side of the virtual quadrangle carrying the second first bar dipole magnets (131 a’; 131 b’) of the first set S1 and of the second set S2. The same apply for a fourth set S4 and a nth set Sn.

[0093] Preferably, the virtual quadrangle has two substantially parallel sides and is selected from the group consisting of squares, rectangles, rhombuses, parallelograms, isocele trapezoids; more preferably the virtual quadrangle has two pairs of two substantially parallel sides and is selected from the group consisting of squares and rectangles.

[0094] The first first bar dipole magnet (131 a) of the first set S1 and the first first bar dipole magnet (131 b) of the second set S2 have an opposite magnetic direction, for example and as shown in Fig. 2A, the first first bar dipole magnet (131 a) of the first set S1 has its South Pole pointing towards the periphery while the first first bar dipole magnet (131 b) of the second set S2 has its North Pole pointing towards the periphery. The second first bar dipole magnet (131 a’) of the first set S1 and the second first bar dipole magnet (131 b’) of the second set S2 have an opposite magnetic direction; for example and as shown in Fig. 2A, the second first bar dipole magnet (131 a’) of the first set S1 has its South Pole pointing towards the periphery while the second first bar dipole magnet (131 b’) of the second set S2 has its North Pole pointing towards the periphery. For embodiments with a third set S3 (as shown in Fig. 1 H), ... , a nth set Sn, the first first bar dipole magnet (131 c) of the third set S3 and the first first bar dipole magnet (131 b) of the second set S2 have an opposite magnetic direction; the first first bar dipole magnetSICPA HOLDING SA 272 626 t8(131 n) of the nth set Sn and the first first bar dipole magnet (131 (n-1)) of the (n-1)th set S(n-1) have an opposite magnetic direction; in other words, the first first bar dipole magnets of neighboring sets have an opposite magnetic direction, and similarly for the second first bar dipole magnets of neighboring sets.

[0095] The first first bar dipole magnet (131 b) of the second set S2 is arranged at a distance d3 from the first first bar dipole magnet (131 a) of the first set S1 and the second first bar dipole magnet (131 b’) of the second set S2 is arranged at the distance d3 from the second first bar dipole magnet (131 a’) of the first set S1. The distance d3 between the first first bar dipole magnet (131 b) of the second set S2 and the first first bar dipole magnet (131 a) of the first set S1 may be the same as or may be different from, preferably the same as, the distance d3 between the second first bar dipole magnet (131 b’) of the second set S2 and the second first bar dipole magnet (131 a’) of the first set S1 . Preferably, the distance d3 is between about 0 mm and about 10 mm, more preferably between about 0 mm and about 5 mm, even more preferably about 0.5 mm to about 1 .5 mm. The same applies for a third set S3, a fourth set S4 and a nth set Sn.

[0096] Each of the first set S1 and second set S2 and optional third set S3 and optional nth set Sn of the magnetic assembly (130) described herein comprises the second dipole magnet (132a; 132b; 132c; etc.) described herein. The second dipole magnet (132a; 132b) of the first set S1 and of the second S2 have their magnetic axis substantially perpendicular to the first plane and to the substrate (120) surface during the process described herein. The same applies for the second dipole magnets (132c, 132d, ... ,132n) of a third set S3, a fourth set S4 and a nth set Sn.

[0097] The second dipole magnet (132a) of the first set S1 and the second dipole magnet (132b) of the second set S2 have an opposite magnetic direction. For embodiments with a third set S3 (as shown in Fig. 1 H), ... , a nth set Sn, the second dipole magnet (132c) of the third set S3 and the second dipole magnet (132b) of the second set S2 have an opposite magnetic direction, the second dipole magnet (132n) of the nth set Sn and the second dipole magnet (132(n-1)) of the (n-1)th set S(n-1) have an opposite magnetic direction; in other words, the second dipole magnets of neighboring sets have an opposite magnetic direction.

[0098] The second dipole magnet (132a) of the first set S1 is arranged between the first first bar dipole magnet (131 a) and the second first bar dipole magnet (131 a’) of said first set S1 and the second dipole magnet (132b) of the second set S2 is arranged between the first first bar dipole magnet (131 b) and the second first bar dipole magnet (131 b’) of said second set S2. The same applies for the magnets of a third set S3, a fourth set S4 and a nth set Sn.

[0099] The second dipole magnet (132a) of the first set S1 and the second dipole magnet (132b) of the second set S2 have an opposite magnetic direction, wherein the second dipole magnet (132a) of the first set S1 has its South Pole pointing towards the first plane when the first first bar dipole magnet (131 a) and the second first bar dipole magnet (131 a’) of said first set S1 have their South Poles pointing towards the periphery of the magnetic assembly (130) of the magnetic device (100), or the second dipole magnet (132a) of the first set S1 has its North Pole pointing towards the first plane when the first first bar dipole magnet (131 a) and the second first bar dipole magnet (131 a’) of said first set S1 have their North Poles pointing towards the periphery of the magnetic assembly (130) of the magnetic device 1SICPA HOLDING SA 272 626 t8(100).

[0100] According to one embodiment shown for examples in Figs 2A-D, 3A-D, 4A and 5A, the second dipole magnets (132a and 132b) of the first set S1 and of the second set S2 consist of single magnets.

[0101] According to another embodiment shown for examples in Figs 2E-G, 3E, 4B and 5B, the second dipole magnets (132a and 132b) of the first set S1 and of the second set S2 consist of a combination of two or more second magnets (132a1 i, 132b1'), preferably four or more magnets, wherein said two or more, preferably four or more second magnets (132a1 i, 132b1'), have the same magnetic direction in each set. In each set, the second dipole magnets (132a1 i, 132b1') may have the same shape or may have a different shape, preferably have a same shape. In each set, the second dipole magnets (132a1-', 132b1') may be made of the same material or may be made from a different material, preferably made of the same material. The combination of two or more second magnets (132a1 i, 132b1') of the first set S1 and of the second set S2 may have the same shape or may have a different shape, preferably have a same shape (as shown in Figs 2E-G, 3E, 4B and 5B). The same applies forthe second dipole magnets of a third set S3, a fourth set S4 and a nth set Sn.

[0102] The second dipole magnets (132a and 132b) of the first set S1 and of the second set S2 consisting of single magnets and the combination of two or more second magnets (132a1 i, 132b1') of the first set S1 and of the second set S2 may be centered or vertically shifted or laterally shifted relative to the pair of first bar dipole magnets (131 and 13T) of the corresponding set S. The second dipole magnets (132a and 132b) of the first set S1 and of the second set S2 consisting of single magnets and the combination of two or more second magnets (132a1 i, 132b1') of the first set S1 and of the second set S2 may be arranged in a symmetric manner in respect to the other or may be arranged in an asymmetric manner. The same applies for the magnets of a third set S3, a fourth set S4 and a nth set Sn.

[0103] The magnetic assembly (130) described herein comprises i) the first first bar dipole magnet (131 a), the second first bar dipole magnet (131 a’) and the second dipole magnet (132a) of the first set S1 and ii) the first first bar dipole magnet (131 b), the second first bar dipole magnet (131 b’) and the second dipole magnet (132b) of the second set S2 at least partially or fully embedded in the nonmagnetic supporting matrix (135). Preferably, the first first bar dipole magnets (131 a and 131 b), the second first bar dipole magnet (131 a’ and 131 b’), the second dipole magnets (132a and 132b) and the non-magnetic supporting matrix (135) have their uppermost surface flush with each other. For embodiments with a nth set Sn (n=3, 4, 5, etc.), the first first bar dipole magnets (131 c, 131d, ... , 131 n) of the n sets, the second first bar dipole magnet (131 c’, 131 d’, ... , 131 n’) of the n sets and the second dipole magnets (132c, 132d, ... , 132n) of the n sets and the supporting matrix (135) have their uppermost surface flush with each other.

[0104] According to one embodiment shown for example in Figs 3A-E, the magnetic assembly (130) of the magnetic device (100) described herein further comprises the pair of a first third bar dipole magnet (133a) and a second third bar dipole magnet (133b) described herein, wherein said first third bar dipole magnet (133a) and second third bar dipole magnet (133b) are at least partially or fully embedded in the non-magnetic supporting matrix (135).

[0105] As shown for example in Fig. 3A, the first third bar dipole magnet (133a) and the second thirdSICPA HOLDING SA 272 626 t8 bar dipole magnet (133b) are arranged on two parallel sides of the virtual quadrangle (“Q” in Fig. 3A) lacking the first first bar dipole magnets (131 a and 131 b) and lacking the second first bar dipole magnets (131 a’ and 131 b’), wherein said two parallel sides are substantially perpendicular to the sides of the virtual quadrangle comprising the first first bar dipole magnets (131 a and 131 b) and the second first bar dipole magnets (131 a’ and 131 b’).

[0106] The first third bar dipole magnet (133a) and the second third bar dipole magnet (133b) have a magnetic axis substantially parallel to the first plane and to the substrate (120) surface during the process described herein and have a same magnetic direction; the first third bar dipole magnet (133a) has its North Pole pointing towards the second dipole magnet (132a) of the first set S1 , when said neighbouring second dipole magnet (132a) has its South Pole pointing towards the first plane or has its South Pole pointing towards the second dipole magnet (132a) of the first set S1 when said neighbouring second dipole magnet (132a) has its North Pole pointing towards the first plane, or in other words the first third bar dipole magnet (133a) has its the North Pole pointing towards the periphery when the North Pole of the first first bar dipole magnet (131 a) of the first set S1 and the North Pole of the second first bar dipole magnet (131 a’) of the first set S1 point towards the periphery and with the South Pole of the first third bar dipole magnet (133a) pointing towards the periphery when the South Pole of the first first bar dipole magnet (131 a) of the first set S1 and the South Pole of the second first bar dipole magnet (131 a’) of the first set S1 point towards the periphery.

[0107] For embodiments with a nth set Sn (n = 3, 4, 5, etc.), the first third dipole magnet (133a) is arranged in the vicinity of the first set S1 and the second third bar dipole (133b) is arranged in the vicinity of the nth set Sn, i.e. the last set Sn.

[0108] The first third bar dipole magnet (133a) and the second third bar dipole magnet (133b) may have the same shape as or may have a different shape, preferably have the same shape. The first third bar dipole magnet (133a) and second third bar dipole magnet (133b) may be made from the same material as or may be made from a different material, preferably are made from the same material. The same applies if a third set S3, a fourth set S4 and a nth set Sn are present.

[0109] As shown for example in Figs 3 and 5, for embodiments wherein the virtual quadrangle is a virtual rectangle, the first first bar dipole magnets (131 a; 131 b) of the first set S1 and of the second set S2 are arranged on a side of the virtual rectangle Q, the second first bar dipole magnets (131 a’; 131 b’) of the first set S1 and of the second set S2 are arranged on the opposite side of the virtual rectangle; and the first third bar dipole magnet (133a) is arranged on a side of the virtual rectangle lacking the first first bar dipole magnets (131 a; 131 b) and the second first bar dipole magnets (131 a’; 131 b’), and the second third bar dipole magnet (133b) is arranged on the opposite side of the virtual rectangle lacking the first first bar dipole magnets (131 a; 131 b), the second first bar dipole magnets (131 a’; 131 b’) and the first third bar dipole magnet (133a).

[0110] Preferably, the first first bar dipole magnets (131 a and 131 b), the second first bar dipole magnets (131 a’ and 131 b’), the second dipole magnets (132a and 132b), the first third bar dipole magnet (133a), the second third bar dipole magnet (133b) and the supporting matrix (135) have their uppermost surface flush with each other.SICPA HOLDING SA 272 626 t8

[0111] According to one embodiment shown for example in Figs 4, the magnetic assembly (130) of the magnetic device (100) described herein comprises a fourth bar dipole magnet (134) arranged on a virtual line “L” in the virtual quadrangle (shown in Fig. 4A as “Q”) being substantially perpendicular to the sides of the virtual quadrangle comprising the first first bar dipole magnets (131 a; 131 b) and the second first bar dipole magnets (131 a’; 131 b’) and between the first set S1 and the second set S2. The fourth bar dipole magnet (134) has its magnetic axis substantially parallel to the first plane and to the substrate (120) surface during the process described herein with its North pole pointing towards the second dipole magnet (132a or 132b) having its South pole pointing towards the first plane. The same applies for the fourth bar dipole magnets between a second set S2 and a third set S3, between a third set S3 and a fourth set S4, and between a (n-1 )-th set S(n-1) and a nth set Sn.

[0112] As shown for example in Figs 5, for embodiments wherein the virtual quadrangle is a virtual rectangle, the first first bar dipole magnets (131 a; 131 b) of the first set S1 and of the second set S2 are arranged on a side of the virtual rectangle Q, the second first bar dipole magnets (131 a’; 131 b’) of the first set S1 and of the second set S2 are arranged on the opposite side of the virtual rectangle; the first third bar dipole magnet (133a) is arranged on a side of the virtual rectangle lacking the first first bar dipole magnets (131 a; 131 b) and the second first bar dipole magnets (131 a’; 131 b’), the second third bar dipole magnet (133b) is arranged on the opposite side of the virtual rectangle lacking the first first bar dipole magnets (131 a; 131 b), the second first bar dipole magnets (131 a’; 131 b’) and the first third bar dipole magnet (133a); and the fourth bar dipole magnet (134) is arranged on a virtual line L in the virtual rectangle being substantially perpendicular to the sides of the virtual rectangle comprising the first first bar dipole magnets (131 a; 131 b) and the second first bar dipole magnets (131 a’; 131 b’) and substantially parallel to the sides of the virtual rectangle comprising the first third bar dipole magnet (133a) and the second third bar dipole magnet (133b) and is arranged between the first set S1 and the second set S2.

[0113] According to one embodiment shown for example in Figs 5, the magnetic assembly (130) of the magnetic device (100) described herein comprises the pair of the first third bar dipole magnet (133a) and the second third bar dipole magnet (133b) described herein and the fourth bar dipole magnet (134) described herein.

[0114] Preferably, the first first bar dipole magnets (131 a and 131 b), the second first bar dipole magnets (131 a’ and 131 b’), the second dipole magnets (132a and 132b), the first third bar dipole magnet (133a), the second third bar dipole magnet (133b), the fourth bar dipole magnet (134) and the supporting matrix (135) have their uppermost surface flush with each other. The same applies for the magnets of a third set S3, a fourth set S4 and a nth set Sn.

[0115] The magnetic device (100) described herein comprises the magnetic-field generating device (140) described herein. The magnetic-field generating device (140) is a bar dipole magnet having its magnetic axis substantially parallel to the first plane and to the substrate (120) surface during the process described herein.

[0116] According to one embodiment shown for examples in Figs 1A-D and 1 F, the magnetic-field generating device (140) consists of a single magnet.SICPA HOLDING SA 272 626 t8

[0117] According to another embodiment shown for examples in Figs 1 E and 1 G, the magnetic-field generating device (140) consists of a combination of two or more bar dipole magnets (141 a, 141 b, etc.) such as for example ten bar dipole magnets (1411 1°) in Figs 1 E and 1 G, wherein said two or more bar dipole magnets (141 a, 141 b, etc.) have the same magnetic direction and have their magnetic axes substantially parallel to the first plane and to the substrate (120) surface during the process described herein. When the magnetic-field generating device (140) is a combination of two or more bar dipole magnets (141 a, 141 b, etc.), said two or more bar dipole magnets (141 a, 141 b, etc.) may be separated by one or more spacer pieces made of a non-magnetic material such as those described for the nonmagnetic supporting matrix (135). The two or more bar dipole magnets (141 a, 141 b, etc.) of the combination of two or more bar dipole magnets (141 a, 141 b, etc.) may have a same shape or may have a different shape, preferably have a same shape. The two or more bar dipole magnets (141 a, 141 b, etc.) of the combination may be made of the same material or may be made from a different material, preferably made of the same material. Examples of suitable magnetic-field generating devices (140) consisting of a combination of two or more bar dipole magnets (141 a, 141 b, etc.) are disclosed in WO 2020 / 052862 A1 (magnetic-field generating device (240) of Fig. 2A or magnetic-field generating device (540) of Fig. 5A), and in WO 2017 / 148789 A1 (magnetic-field generating device (1340) of Fig. 13A or magnetic-field generating device (1440) of Fig. 14A).

[0118] The surface of the magnetic-field generating device (140) is preferably at least as large as the surface of i) the first set S1 , ii) the second set S2 and iii) the optional nth Set Sn (n = 3, 4, 5, etc.) (for example and as shown in Fig. 1A, the surface of the magnetic-field generating device (140) is at least as large as the surface of the first set S1 and the second set S2 so as to overlap i) the first bar dipole magnets (131 a and 131 a’) and the second dipole magnet (132a) of said first set S1 and ii) the first bar dipole magnets (131 b and 131 b’) and the second dipole magnet (132b) of the second set S2; for example and as shown in Fig. 1 H, the surface of the magnetic-field generating device (140) is at least as large as the surface of i) the first set S1 , ii) the second set S2 and iii) the third set S3 so as to overlap i) the first bar dipole magnets (131 a and 131 a’) and the second dipole magnet (132a) of the first set S1 , ii) the first bar dipole magnets (131 b and 131 b’) and the second dipole magnet (132b) of the second set S2, and iii) the first bar dipole magnets (131 c and 131 c’) and the second dipole magnet (132c) of the third set S3; and for example the surface of the magnetic-field generating device (140) is at least as large as the surface of i) the first set S1 , ii) the second set S2 and iii) the nth set Sn so as to overlap i) the first bar dipole magnets (131 a and 131 a’) and the second dipole magnet (132a) of the first set S1 , ii) the first bar dipole magnets (131 b and 131 b’) and the second dipole magnet (132b) of the second set S2, and iii) the first bar dipole magnets (131 n and 131 n’) and the second dipole magnet (132n) of the nth set Sn). The surface of the magnetic-field generating device (140) is preferably at least as large as the surface of i) the first set S1 , ii) the second set S2, iii) the optional nth set Sn and iv) the third bar dipole magnets (133a and 133b) when present so as to overlap the first bar dipole magnets (131 a, 131 a’, 131 b, 131 b’, 131 n and 131 n’), the second dipole magnets (132a, 132b and 132n) as described herein and the third bar dipole magnets (133a and 133b).

[0119] During the process described herein and as shown in Figs 1 , the magnetic-field generating device (140) has either its magnetic axis substantially parallel to the machine feed direction (shown bySICPA HOLDING SA 272 626 t8 the grey arrow in Figs 1A, 1 D and 1 E) or has its magnetic direction substantially perpendicular to the machine feed direction (shown by the grey arrow in Figs 1 B,1 C, 1 F and 1 G). For the embodiments wherein the magnetic-field generating device (140) has its magnetic direction substantially perpendicular to the machine feed direction, said magnetic-field generating device (140) preferably has either i) its North Pole being on top of (as shown in Figs 1 B and 1 C) or below (as shown in Figs 1 F and 1 G) the first set S1 comprising the first bar dipole magnets (131) having their North Poles pointing towards the center of the magnetic assembly (130) of the magnetic device (100) and comprising the second dipole magnet (132a) having its South Pole pointing towards the first plane and the substrate (120) during the process described herein (as shown in Figs 1 B, 1 F and 1G) or ii) its South Pole being on top of or below the first set S1 comprising the first bar dipole magnets (131) having their North Poles pointing towards the center of the magnetic assembly (130) of the magnetic device (100) and comprising the second dipole magnet (132a) having its South Pole pointing towards the first plane and the substrate (120) (as shown in Fig. 1 C).

[0120] As described herein, the optical effect layers (OELs) produced with the magnetic devices (100), the magnetic apparatuses (1000) and the processes described herein provide the optical impression of two or more loop-shaped bodies having their shape and / or size and / or their brightness varying in opposite directions upon tilting the OELs. For embodiments wherein the magnetic-field generating device (140) has its magnetic axis substantially parallel to the machine feed direction (shown by the grey arrow in Figs 1 A, 1 D and 1 E), the OELs provide the optical impression of two or more loop-shaped bodies having their shape and / or size and / or their brightness varying in opposite directions upon tilting up and down the OELs (see “V” direction in Fig. 6A and examples E1 , E8, E11 , E14, E17, E23, E26, E30 and E33-E36). For embodiments wherein the magnetic-field generating device (140) has its magnetic axis substantially perpendicular to the machine feed direction (shown by the grey arrow in Figs 1 B, 1 C, 1 F and 1G), the OELs provide the optical impression of two or more loop-shaped bodies having their shape and / or size and / or their brightness varying in opposite directions upon tilting left and right the OELs (see “H” direction in Fig. 6A and examples E2-E7, E9, E10, E12, E13, E15, E16, E18- E22, E24, E25, E27-E29, E31 , E32, E37 and E38).

[0121] For the embodiments wherein the magnetic-field generating device (140) is arranged on top of the magnetic assembly (130) described herein, the distance between the lowermost surface of the magnetic-field generating device (140) and the uppermost surface of the magnetic assembly (130) is preferably between about 0 and about 5 mm, more preferably between about 0 and about 2 mm and still more preferably between 0 mm and 1 mm. For the embodiments wherein the magnetic assembly (130) is arranged on top of the magnetic-field generating device (140), the distance between the lowermost surface of the magnetic assembly (130) and the uppermost surface of magnetic-field generating device (140) is preferably between about 0 and about 5 mm, more preferably between about 0 and about 2 mm and still more preferably between 0 mm and 1 mm.

[0122] The magnetic device (100) described herein comprises the pole piece (150) described herein. A pole piece denotes a structure composed of a material having high magnetic permeability, preferably a permeability between about 2 and about 1 ,000,000 N A-2(Newton per square Ampere), more preferably between about 5 and about 50,000 N A-2and still more preferably between about 10 andSICPA HOLDING SA 272 626 t8 about 10,000 N A-2. Pole pieces serve to direct the magnetic field produced by magnets. According to one embodiment, the pole piece (150) described herein is made from 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-nickels alloys iron-nickel-cobalt alloys (Fernico-type materials), Heusler-type alloys (such as Cu2MnSn or Ni2MnAI), low silicon steels, low carbon steels, silicon irons (electrical steels), iron-aluminium alloys, iron-aluminium-silicon alloys, amorphous metal alloys (e.g. alloys like Metglas®, iron-boron alloys), nanocrystalline soft magnetic materials (e.g. Vitroperm®) and combinations thereof, more preferably selected from the group consisting of iron, cobalt, nickel, low carbon steels, silicon iron, nickel-iron alloys and cobalt-iron alloys and combinations thereof. Preferably, the pole piece (150) described herein is made from iron or steel or from a plastic material in which magnetizable particles are dispersed, more preferably from steel.

[0123] The pole piece (150) may be a loop-shaped pole piece or a solid-shaped pole piece (i.e. a pole piece which does not comprise a central area lacking the material of said pole piece), preferably a solidshaped pole piece, more preferably a square-shaped pole piece, a rectangle-shaped pole piece or a disc-shaped pole piece, still more preferably a square-shaped pole piece, a rectangle-shaped pole piece.

[0124] For the embodiments wherein the magnetic-field generating device (140) is arranged on top of the pole piece (150) described herein, the distance between the lowermost surface of the magnetic- field generating device (140) and the uppermost surface of the pole piece (150) is preferably between about 0 and about 5 mm, preferably between about 0 and about 2 mm. and still more preferably between 0 mm and 1 mm. For the embodiments wherein the magnetic assembly (130) is arranged on top of the pole piece (150) described herein, the distance between the lowermost surface of the magnetic assembly (130) and the uppermost surface of the pole piece (150) is preferably between about 0 and about 5 mm, preferably between about 0 and about 2 mm. and still more preferably between 0 mm and 1 mm.

[0125] The magnetic device (100) described herein may further comprise an engraved plate (160) (not shown in the Figures), wherein said engraved plate (160) is arranged on top of the magnetic-field generating device (140) (for the embodiments wherein the magnetic-field generating device (140) is arranged on top of the magnetic assembly (130)) or on top of the magnetic assembly / 130) (for the embodiments wherein magnetic assembly (130) is arranged on top of the magnetic-field generating device (140)). For the embodiments wherein the engraved plate (160) is arranged on top of the magnetic-field generating device (140) described herein, the distance between the lowermost surface of the engraved plate (160) and the uppermost surface of the magnetic-field generating device (140) is preferably from about 0 mm to about 10 mm, more preferably from about 1 mm to about 3 mm. For the embodiments wherein the engraved plate (160) is arranged on top of the magnetic assembly (130) described herein, the distance between the lowermost surface of the engraved plate (160) and the uppermost surface of the magnetic assembly (130) is preferably from about 0 mm to about 10 mm, more preferably from about 1 mm to about 3 mm.

[0126] According to one embodiment, the magnetic apparatus (1000) described herein comprises the engraved plate (160), wherein said engraved plate (160) is arranged on top of the holding case (170)SICPA HOLDING SA 272 626 t8 and the distance between the lowermost surface of the engraved plate (160) and the uppermost surface of the holding case (170) is preferably from about 0 mm to about 10 mm, more preferably from about 0 mm to about 1 mm.

[0127] According to one embodiment, the engraved plate (160) described herein is an engraved hard magnetic plate (160) made from a permanent magnetic powder material and a polymer. The engraved hard magnetic plate (160) described herein may typically be produced by an injection molding process or by metal or laser engraving. Preferred permanent magnetic powder materials include cobalt, iron and their alloys, chromium dioxide, generic magnetic oxide spinels, generic magnetic garnets, generic magnetic ferrites including the hexaferrites such as calcium-, strontium-, and barium- hexaferrite (CaFe12019, SrFe12019, BaFe12019, respectively), generic alnico alloys, generic samarium-cobalt (SmCo) alloys, and generic rare-earth-iron-boron alloys (such as NdFeB), as well as the permanent- magnetic chemical derivatives thereof (such as indicated by the term generic) and mixtures thereof. Plates made of a composite material comprising a polymer and a permanent magnetic powder are obtainable from many different sources, such as from Bomatec, Hbri, CH, ARNOLD® Magnetic Technologies (Plastiform®) or from Materiali Magnetici, Albairate, Milano, IT (Plastoferrite).

[0128] According to one embodiment, the engraved plate (160) described herein is an engraved soft magnetic plate (160) and comprises one or more soft magnetic materials, i.e. materials having a low coercivity and a high permeability p. Their coercivity is lower than 1000 Am-1as measured according to IEC 60404-1 :2000, to allow for a fast magnetization and demagnetization. Suitable soft magnetic materials have a maximum relative permeability / ZRmax of at least 5, where the relative permeability / ZR is the permeability of the material p relative to the permeability of the free space po ( / ZR = p / po) (Magnetic Materials, Fundamentals and Applications, 2ndEd., Nicola A. Spaldin, p. 16-17, Cambridge University Press, 2011). Soft magnetic materials are described, for example, in the following handbooks: (1) Handbook of Condensed Matter and Materials Data, Chap. 4.3.2, Soft Magnetic Materials, p. 758-793, and Chap. 4.3.4, Magnetic Oxides, p. 811-813, Springer 2005; (2) Ferromagnetic Materials, Vol. 1 , Iron, Cobalt and Nickel, p. 1-70, Elsevier 1999; (3) Ferromagnetic Materials, Vol. 2, Chap. 2, Soft Magnetic Metallic Materials, p. 55-188, and Chap. 3, Ferrites for non-microwave Applications, p. 189-241 , Elsevier 1999; (4) Electric and Magnetic Properties of Metals, C. Moosbrugger, Chap. 8, Magnetically Soft Materials, p. 196-209, ASM International, 2000; (5) Handbook of modern Ferromagnetic Materials, Chap. 9, High-permeability High-frequency Metal Strip, p. 155-182, Kluwer Academic Publishers, 2002; and (6) Smithells Metals Reference Book, Chap. 20.3, Magnetically Soft Materials, p. 20-9 - 20-16, Butterworth-Heinemann Ltd, 1992. The engraved soft magnetic plate (160) described herein may either be a plate made of one or more metals, alloys or compounds of low coercivity and high magnetic permeability (hereafter referred as “soft magnetic metal plate”) or a plate made of a composite comprising soft magnetic particles dispersed in a non-magnetic material (hereafter referred as “engraved soft magnetic composite plate”).

[0129] According to one embodiment, the engraved soft magnetic metal plate (160) described herein is made of one or more soft magnetic metals or alloys easily workable as sheets or threads. Preferably, the engraved soft magnetic metal plate (160) described herein is made from one or more materials selected from the group consisting of iron, cobalt, nickel, nickel-molybdenum alloys, nickel-iron alloysSICPA HOLDING SA 272 626 t8(permalloy or supermalloy-type materials), cobalt-iron alloys, cobalt-nickels alloys iron-nickel-cobalt alloys (Fernico-type materials), Heusler-type alloys (such as Cu2MnSn or Ni2MnAI), low silicon steels, low carbon steels, silicon irons (electrical steels), iron-aluminium alloys, iron-aluminium-silicon alloys, amorphous metal alloys (e.g. alloys like Metglas®, iron-boron alloys), nanocrystalline soft magnetic materials (e.g. Vitroperm®) and combinations thereof, more preferably selected from the group consisting of iron, cobalt, nickel, low carbon steels, silicon irons, nickel-iron alloys and cobalt-iron alloys and combinations thereof.

[0130] According to another embodiment, the engraved soft magnetic plate (160) described herein is made of a composite comprising from about 25 wt-% to about 95 wt-% of soft magnetic particles dispersed in a non-magnetic material, the weight percents being based on the total weight of the engraved soft magnetic plate (160). Preferably, the composite of the engraved soft magnetic plate (160) comprises from about 50 wt-% to about 90 wt-%, of soft magnetic particles, the weight percents being based on the total weight of the engraved soft magnetic plate (160). The soft magnetic particles described herein are made of one or more soft magnetic materials preferably selected from the group consisting of iron (especially iron pentacarbonyl, also called carbonyl iron), nickel (especially nickel tetracarbonyl, also called carbonyl nickel), cobalt, soft magnetic ferrites (e.g. manganese-zinc ferrites and nickel-zinc ferrites), soft magnetic oxides (e.g. oxides of manganese, iron, cobalt and nickel), soft silicon irons, and combinations thereof, more preferably selected from the group consisting of carbonyl iron, carbonyl nickel, cobalt, soft silicon irons and combinations thereof. The engraved soft magnetic plate (160) described herein is made of a composite, wherein said composite comprises the soft magnetic particles described herein dispersed in a non-magnetic material. Suitable non-magnetic materials include without limitation polymeric materials forming a matrix for the dispersed soft magnetic particles. The polymeric matrix-forming materials may be one or more thermoplastic materials or one or more thermosetting materials or comprise one or more thermoplastic materials or one or more thermosetting materials. Suitable thermoplastic materials include without limitation polyamides, copolyamides, polyphtalimides, polyolefins, polyesters, polytetrafluoroethylenes, polyacrylates, polymethacrylates (e.g. PMMA), polyimides, polyetherimides, polyetheretherketones, polyaryletherketones, polyphenylene sulfides, liquid crystal polymers, polycarbonates and mixtures thereof. Suitable thermosetting materials include without limitation epoxy resins, phenolic resins, polyimide resins, polyester resins, silicon resins and mixtures thereof. The soft magnetic plate (160) described herein is made of a composite comprising from about 5 wt-% to about 75 wt-% of the nonmagnetic material described herein, the weight percents being based on the total weight of the engraved soft magnetic metal plate (160).

[0131] The engraved plate (160) described herein comprises one or more engraved indentations and / or one or more engraved voids preferably having the shape of one or more indicia.

[0132] According to one embodiment, the magnetic device (100) described herein further comprises one or more non-magnetic wedges (not shown in the Figures), wherein said one or more non-magnetic wedges are arranged between the magnetic-field generating device (140) and the magnetic assembly (130) and / or are arranged between the magnetic assembly (130) or the magnetic-field generating device (140) and the pole piece (150).SICPA HOLDING SA 272 626 t8

[0133] Also described herein are uses of the magnetic devices (100) described herein for producing the optical effect layers (OELs) described herein.

[0134] Also described herein are magnetic apparatuses (1000) comprising the magnetic device (100) described herein, the holding case (170) described herein and the holding case bottom lid (171) described herein. The holding case (170) and the holding case bottom lid (171) advantageously allow to protect the magnetic device (100) from contamination and mechanical damage and the holding case (170) advantageously allows to provide a smooth surface for supporting the substrate (120) carrying the coating layer (110) made of the radiation curable coating composition comprising the non-spherical magnetic or magnetizable pigment particles. A further function of the holding case (170) is to provide an appropriate distance between uppermost element being either the magnetic-field generating device (140) or the magnetic assembly (130) of the magnetic device (100) and the substrate (120) carrying the coating layer (110). According to one embodiment, the holding case (170) has a curved surface suitable to match the surface of a rotating magnetic cylinder described hereafter.

[0135] The holding case (170) and the holding case bottom lid (171) are made of one or more nonmagnetic materials such as those disclosed herein for the non-magnetic supporting matrix (135).

[0136] According to one embodiment, the magnetic apparatuses (1000) described herein further comprises an engraved plate (160) (not shown in the Figures), wherein said engraved plate (160) of the magnetic apparatus (1000) described herein is arranged on top of the holding case (170).

[0137] The engraved plate (160) may be an engraved hard magnetic plate (160) or an engraved soft magnetic plate (160) such as those described herein for the magnetic device (100).

[0138] The distance between the uppermost surface of the engraved plate (160) and the lowermost surface of the substrate (120) facing the magnetic apparatus (1000) is preferably between about 0 and about 1 mm and more preferably is about 0 mm.

[0139] Also described herein are uses of the magnetic apparatuses (1000) described herein for producing the optical effect layers (OELs) described herein.

[0140] According to one embodiment, the magnetic apparatus (1000) described herein is used in conjunction with a rotating magnetic cylinder (RMC), wherein the one or more magnetic apparatuses (1000) are mounted to circumferential or axial grooves of the rotating magnetic cylinder. The rotating magnetic cylinder is meant to be used in, or in conjunction with, or being part of a printing or coating equipment, and bearing the one or more magnetic apparatuses (1000) described herein. In an embodiment, the rotating magnetic cylinder is part of a rotary, sheet-fed or web-fed industrial printing press that operates at high printing speed in a continuous way.

[0141] According to another embodiment, the magnetic apparatus (1000) described herein is used in conjunction with a flatbed unit, wherein the one or more magnetic apparatuses (1000) are mounted to recesses of the flatbed unit. The flatbed unit is meant to be used in, or in conjunction with, or being part of a printing or coating equipment, and bearing the one or more magnetic apparatuses (1000) described herein described herein. In an embodiment, the flatbed unit is part of a sheet-fed industrial printing press that operates in a linear and discontinuous way.

[0142] According to another embodiment, the magnetic apparatus (1000) described herein is used in conjunction with a rotating belt, wherein the one or more magnetic apparatuses (1000) are mounted toSICPA HOLDING SA 272 626 t8 said belt. In an embodiment, the belt is part of a rotary, sheet-fed or web-fed industrial printing press that operates at high printing speed.

[0143] The printing apparatuses comprising the rotating magnetic cylinder described herein or the flatbed unit described herein or the belt described herein may include a substrate feeder for feeding a substrate such as those described herein having thereon a layer comprising non-spherical magnetic or magnetizable pigment particles described herein, so that the magnetic apparatuses (1000) generate a magnetic field that acts on the pigment particles to orient them to form the OEL described herein. In an embodiment of the printing apparatuses comprising a rotating magnetic cylinder described herein, the substrate is fed by the substrate feeder under the form of sheets or of a web. In an embodiment of the printing apparatuses comprising the flatbed unit described herein, the substrate is fed under the form of sheets.

[0144] According to one embodiment and in addition to the one and more magnetic apparatuses (1000) used with the rotating magnetic cylinder or the flatbed unit or the belt described herein, a coating or printing unit for applying the radiation curable coating composition described herein on the substrate described herein is used.

[0145] According to one embodiment and in addition to the one or more magnetic apparatuses (1000) used with the rotating magnetic cylinder or the flatbed unit or the belt and the optional coating or printing unit described herein, a curing unit for at least partially curing the radiation curable coating composition comprising the non-spherical magnetic or magnetizable pigment particles that have been magnetically oriented thereby is used so as to fix the orientation and position of the particles.

[0146] The optical effect layers (OELs) described herein may have any shape, wherein said shape may be continuous or discontinuous. According to one embodiment, the OELs described represent one or more indicia, dots and / or lines, wherein said one or more indicia, dots and / or lines may be spaced apart from each other by a free area.

[0147] The optical effect layers (OELs) described herein may be provided directly on the substrates (120) described herein and on which they shall remain permanently (such as for banknote applications). Alternatively, the OELs may also be provided on temporary substrates (120) for production purposes, from which the OELs are subsequently removed. This may for example facilitate the production of the OELs, particularly while the binder material is still in its fluid state. Thereafter, after at least partially curing the radiation curable coating compositions for the production of the OELs, the temporary substrates (120) may be removed from the OELs.

[0148] Alternatively, an adhesive layer may be present on the OEL or may be present on the substrate (120) comprising an OEL, said adhesive layer being on the side of the substrate opposite the side where the OEL is provided or on the same side as the OEL and above the OEL. Therefore, an adhesive layer may be applied to the OEL and / or to the substrate (120). Such an article may be attached to all kinds of documents or other articles or items without printing or other processes involving machinery and rather high effort. Alternatively, the substrate (120) described herein comprising the OEL described herein may be in the form of a transfer foil, which can be applied to a document or to an article in a separate transfer step. Forthis purpose, the substrate (120) is provided with a release coating, on whichSICPA HOLDING SA 272 626 t8 the OEL is produced as described herein. One or more adhesive layers may be applied over the so produced OEL.

[0149] Alternatively, the optical effect layers (OELs) may be produced onto auxiliary substrates (120) such as for example a security thread, security stripe, a foil, a decal, a window or a label and consequently transferred to a security document in a separate step.

[0150] If desired, a primer layer may be applied to the substrate (120) prior to the step i). This may enhance the quality of the OEL described herein or promote adhesion. Examples of such primer layers may be found in WO 2010 / 058026 A2.

[0151] With the aim of increasing the durability through soiling or chemical resistance and cleanliness and thus the circulation lifetime of an article, a security document or article or a decorative element or object comprising the OEL obtained by the process described herein, or with the aim of modifying their aesthetical appearance (e.g. optical gloss), one or more protective layers may be applied on top of the OEL. When present, the one or more protective layers are typically made of protective varnishes. These may be transparent or slightly colored or tinted and may be more or less glossy. Protective varnishes may be radiation curable compositions, thermal drying compositions or any combination thereof. Preferably, the one or more protective layers are radiation curable compositions, more preferable UV- Vis curable compositions. The protective layers are typically applied after the formation of the OEL.

[0152] The OEL described herein may 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 , said holograms, microlenses and / or micromirrors being applied at a position spaced apart from the OEL or least partially on top or below the OEL.

[0153] The process described herein may further comprise a step of embossing the OEL described herein using for example an embossing dye or an intaglio printing plate as disclosed in WO 2012 / 025206 A2 and WO 2019 / 233624 A1 .

[0154] Also described herein are substrates (120) such as those described herein comprising more than one, i.e. two, three, four, etc. OELs obtained by the process described herein. Also described herein are substrates (120) such as those described herein comprising the more than one, i.e. two, three, four, etc. OELs obtained by the process described herein and one or more additional OELs obtained by processes of the prior art wherein the magnetic orientation pattern of said one or more additional OELs are different from the one or more OELs produced with the process described herein.

[0155] Also described herein are methods of manufacturing the security document or article or the decorative element or object, comprising a) providing the security document or article or the decorative element or object, and b) producing the optical effect layer (OEL) with the process described herein, so that the OEL is comprised by or on the security document or article or the decorative element or object.

[0156] Also described herein are products, in particular security documents and articles, decorative elements and objects, comprising the OEL produced according to the present invention. The products, in particular security documents and articles, and the decorative elements and objects, may comprise more than one (for example two, three, etc.) OELs produced according to the present invention.

[0157] As mentioned herein, the OEL produced according to the present invention may be used for decorative purposes as well as for protecting and authenticating a security document or article. TypicalSICPA HOLDING SA 272 626 t8 examples of decorative elements or objects include without limitation luxury goods, cosmetic packaging, automotive parts, electronic / electrical appliances, furniture and fingernail lacquers. Security documents include without limitation value documents and value commercial goods. Typical example of value documents include without limitation banknotes, deeds, tickets, checks, vouchers, fiscal stamps and tax labels, agreements and the like, identity documents such as passports, identity cards, visas, driving licenses, bank cards, credit cards, transactions cards, access documents or cards, entrance tickets, public transportation tickets or titles and the like, preferably banknotes, identity documents, rightconferring documents, driving licenses and credit cards. The term “value commercial good” refers to packaging materials, in particular for cosmetic articles, nutraceutical articles, pharmaceutical articles, alcohols, tobacco articles, beverages or foodstuffs, electrical / electronic articles, fabrics or jewelry, i.e. articles that shall be protected against counterfeiting and / or illegal reproduction in order to warrant the content of the packaging like for instance genuine drugs. Examples of these packaging materials include without limitation labels, such as authentication brand labels, tamper evidence labels and seals. It is pointed out that the disclosed substrates, value documents and value commercial goods are given exclusively for exemplifying purposes, without restricting the scope of the invention.

[0158] The skilled person can envisage several modifications to the specific embodiments described above without departing from the spirit of the present invention. Such modifications are encompassed by the present invention.

[0159] Further, all documents referred to throughout this specification are hereby incorporated by reference in their entirety as set forth in full herein.EXAMPLES

[0160] The present invention is now described in more details with reference to non-limiting examples. The Examples below provide more details for suitable magnetic apparatuses (1000) comprising a magnetic device (100), and the processes according to the present invention for the production of optical effects layers (OELs) on substrates (120).

[0161] The OELs obtained with the magnetic apparatuses (1000) comprising the magnetic devices (100) and by the process of Examples E1-E38 and shown in Fig. 6B were prepared on a laboratory equipment, wherein said process comprised: a step i) of applying the UV-Vis curable screen printing ink provided in Table 1 so as to form a coating layer (110), a step ii) of orienting the platelet-shaped magnetic pigment particles comprised in the UV-Vis curable screen printing ink using the magnetic apparatuses (1000) described hereafter and in Table 2, and a step iii) of curing the coating layer.

[0162] Examples E1-E38 were independently prepared by using the UV-Vis curable screen printing ink of Table 1 , wherein said ink was applied (step i)) on a substrate (120) (fiduciary paper from Louisenthal) to form a coating layer (110). The UV-Vis curable screen printing ink was applied (step i)) onto the substrate (120) surface, said application being carried out by hand screen printing using a 90T screen so as to form a coating layer (110) having a thickness of about 20 |j.m and having a squared shape (30 mm x 30 mm).

[0163] For examples E1-E33 and E35-E38, the substrate (120) carrying the coating layer (110) wasSICPA HOLDING SA 272 626 t8 arranged on a magnetic apparatus (1000) (step ii)) so as to orient the pigment particles. For example E34, an assembly comprising the substrate (120) carrying the coating layer (110) and the magnetic apparatus (1000) comprising a soft magnetic plate (160) was formed and said assembly (110+120+1000) was moved at a speed of about 1 m / sec in the vicinity and below a same device as the one disclosed in Fig 2A of WO 2021 / 239607 A1. The so-obtained magnetic orientation pattern of the pigment particles was then, partially simultaneously with the orientation step ii) (i.e. while the substrate (120) carrying the coating layer (110) was still in the magnetic field of the magnetic apparatus (1000)) fixed by exposing for about 3 seconds the coating layer (110) to a UV-LED-lamp from Phoseon (Type RX FireFly 25 x 10 mm, 395 nm, 4 W / cm2) (step Hi)).Table 1(*) green-to-blue colorshifting magnetic pigment particles having a flake shape (platelet-shaped pigment particles) of diameter d50 of about 11 |j.m and thickness about 1 |j.m, obtained from Viavi Solutions, Santa Rosa, CA.

[0164] The OELs of the examples E1-E38 were prepared using the apparatuses (1000) shown in Figs 1 , each apparatus (1000) comprising a magnetic device (100) comprising a) a magnetic assembly (130, shown in Figs 2-5) comprising: a first set S1 and a second set S2, each comprising a first first bar dipole magnet (131 a; 131 b), a second first bar dipole magnet (131 a’; 131 b’) and a second dipole magnet (132a; 132b), b) a magnetic-field generating device (140) (shown in Figs 1); c) a pole piece (150) (shown in Figs 1), d) a holding case (170), e) a holding case bottom lid (171) and f) an engraved plate (160) (for examples E30-E34), wherein said apparatuses (1000) and devices (100) are described thereafter.Magnetic apparatus (1000) of Figs 1A-G

[0165] The magnetic apparatus (1000) shown in Fig. 1A-1G comprised:- a magnetic device (100) comprising a) a magnetic assembly (130) comprising magnets embedded in a non-magnetic supporting matrix (135), b) a magnetic-field generating device (140) being a bar dipole magnet for examples E1-E35 and E37 or a combination of ten bar dipole magnets (1411-1°) for example E36 and E38 and c) a pole piece (150),- a holding case (170) with a holding case bottom lid (171), and- an engraved plate (160) for examples E30-E34 arranged on top of the holding case (170),SICPA HOLDING SA 272 626 t8 wherein the magnetic-field generating device (140) was arranged on top of the magnetic assembly (130) and the magnetic assembly (130) was arranged on top of the pole piece (E1-E34), orwherein the magnetic assembly (130) was arranged on top of the magnetic-field generating device (140) and the magnetic-field generating device (140) was arranged on top of the pole piece (150) (E35-E38) as described hereafter.

[0166] The non-magnetic supporting matrix (135) had a length (L4) and a width (L5) of about 30 mm and a thickness (L6) of about 5.4 mm and was made of POM (polyoxymethylene). The non-magnetic supporting matrix (135) comprised indentations for receiving the first first bar dipole magnets (131 a and 131 b), the second first bar dipole magnets (131 a’ and 131 b’), the second dipole magnets (132a and 132b), the two third bar dipole magnets (133a and 133b) when present and the fourth bar dipole magnet (134) when present.

[0167] The holding case (170) was made of a top part with a curved surface suitable to match the surface of a rotating magnetic cylinder of an industrial printing press and comprised a cavity suitable for receiving the magnetic device (100). The top part had a length and width of about 40 mm, a thickness of about 15.1 mm and was made of PPS. The cavity was suitable for receiving the magnetic device (100) made of the magnetic assembly (130), the magnetic field generating device (140), and the pole piece (150). The bottom lid (171) had a length of about 35 mm, a width of about 35 mm, a thickness of about 3 mm and was made of POM.

[0168] The distance (h) between the uppermost surface of the magnetic-field generating device (140) (E31-E34) or the magnetic assembly (130) (E35-E38) and the substrate (120) was about 1.45 mm.

[0169] In Fig. 1A, the magnetic axis of the bar dipole magnet (140) was substantially parallel to the first plane and to the substrate (120) surface during the process and substantially parallel to the machine feed direction (shown by the grey arrow in Fig. 1 A) with its North Pole pointing in the same direction as the second first bar dipole magnet (131 a’) of the first set S1 and in the same direction as the first first bar dipole magnet (131 b) of the second set S2. The first set S1 comprised the first bar dipole magnets (131 a and 131 a’) having their North Poles pointing towards the center of the magnetic assembly (130) and the second dipole magnet (132a) having its South Pole pointing towards the first plane and the substrate (120) surface during the process. The magnetic-field generating device (140) was arranged on top of the magnetic assembly (130) and the magnetic assembly (130) was arranged on top of the pole piece (150).

[0170] In Fig. 1 B, the magnetic axis of the bar dipole magnet (140) was substantially parallel to the first plane and to the substrate (120) surface during the process and substantially perpendicular to the machine feed direction (shown by the grey arrow in Fig. 1 B) with its North Pole being on top of the first set S1 comprising the first bar dipole magnets (131 a and 131 a’) having their North Poles pointing towards the center of the magnetic assembly (130) and comprising the second dipole magnet (132a) having its South Pole pointing towards the first plane and the substrate (120) surface during the process. The magnetic-field generating device (140) was arranged on top of the magnetic assembly (130) and the magnetic assembly (130) was arranged on top of the pole piece (150).

[0171] In Fig. 1 C, the magnetic axis of the bar dipole magnet (140) was substantially parallel to the first plane and to the substrate (120) surface during the process and substantially perpendicular to theSICPA HOLDING SA 272 626 t8 machine feed direction (shown by the grey arrow in Fig. 1 C) with its North Pole being on top of the second set S2 comprising the first bar dipole magnets (131 b and 131 b’) having their South Poles pointing towards the center of the magnetic assembly (130) and comprising the second dipole magnet (132b) having its North Pole pointing towards the first plane and the substrate (120) surface during the process. The magnetic assembly (130) was arranged on top of the magnetic-field generating device (140) and the magnetic-field generating device (140) was arranged on top of the pole piece (150).

[0172] In Fig. 1 D, the magnetic axis of the bar dipole magnet (140) was substantially parallel to the first plane and to the substrate (120) surface during the process and substantially parallel to the machine feed direction (shown by the grey arrow in Fig. 1 D) with its North Pole pointing in the same direction as the second first bar dipole magnet (131 a’) of the first set S1 and in the same direction as the first first bar dipole magnet (131 b) of the second set S2. The magnetic assembly (130) was arranged on top of the magnetic-field generating device (140) and the magnetic-field generating device (140) was arranged on top of the pole piece (150).

[0173] The magnetic apparatus (1000) shown in Fig. 1 E was the same as the magnetic apparatus shown in Fig. 1 D except that the magnetic-field generating device (140) consisted of a combination of ten magnets (1411-14110). The magnetic assembly (130) was arranged on top of the magnetic-field generating device (140) and the magnetic-field generating device (140) was arranged on top of the pole piece (150).

[0174] In Fig. 1 F, the magnetic axis of the bar dipole magnet (140) was substantially parallel to the first plane and to the substrate (120) surface during the process and substantially perpendicular to the machine feed direction (shown by the grey arrow in Fig. 1 F) with its North Pole being below the first set S1 , said first set S1 comprising the first bar dipole magnets (131 a and 131 a’) having their North Poles pointing towards the center of the magnetic assembly (130) and comprising the second dipole magnet (132a) having its South Pole pointing towards the first plane and the substrate (120) surface during the process. The magnetic assembly (130) was arranged on top of the magnetic-field generating device (140) and the magnetic-field generating device (140) was arranged on top of the pole piece (150).

[0175] The magnetic apparatus (1000) shown in Fig. 1G was the same as the magnetic apparatus shown in Fig. 1 F except that the magnetic-field generating device (140) consisted of a combination of ten magnets (1411-14110). The magnetic assembly (130) was arranged on top of the magnetic-field generating device (140) and the magnetic-field generating device (140) was arranged on top of the pole piece (150).Magnetic assembly (130) of Fig. 2A (examples E1-E3)

[0176] Each of the first set S1 and second set S2 comprised a first first bar dipole magnet (131 a; 131 b) and a second first bar dipole magnet (131 a’; 131 b’), said magnets having their magnetic axis substantially parallel to the first plane and to the substrate (120) surface during the process. In each set, the first first bar dipole magnet (131 a; 131 b) and the second first bar dipole magnet (131 a’; 131 b’) had an opposite magnetic direction so that the North Pole of the first bar dipole magnets (131 a and 131 a’) of the first set S1 were pointing towards each other and the South Pole of the first bar dipole magnets (131 b and 131 b’) of the second set S2 were pointing towards each otherSICPA HOLDING SA 272 626 t8

[0177] The first first bar dipole magnets (131 a; 131 b) of the first set S1 and of the second set S2 were both arranged on a side of a virtual quadrangle in the form of a virtual rectangle Q and the second first bar dipole magnets (131 a’; 131 b’) of the first set S1 and of the second set S2 were both arranged on the opposite side of the virtual rectangle Q.

[0178] The first first bar dipole magnets (131 a; 131 b) of the first set S1 and of the second set S2 and the second first bar dipole magnets (131 a’; 131 b’) of the first set S1 and of the second set S2 were made of NdFeB N45 and had a length (L10) of about 10 mm, a width (L11) of about 3 mm and a thickness (L12) of about 5 mm.

[0179] The distance (d1) between each of the two first bar dipole magnets (131 a and 131 a’) of the first set S1 and the edge of the non-magnetic supporting matrix (135) and between each of the two first bar dipole magnets (131 b and 131 b’) of the second set S2 and the edge of the non-magnetic supporting matrix (135) was about 4.5 mm. The distance (d2) between the first bar dipole magnets (131 a, 131 a’, 131 b, 131 b’) and the edge of the non-magnetic supporting matrix (135) was about 1 .5 mm. The distance (d3) between the first first bar dipole magnet (131 b) of the second set S2 and the first first bar dipole magnet (131 a) of the first set S1 and the distance (d3) between the second first bar dipole magnet (131 b’) of the second set S2 and the second first bar dipole magnet (131 a’) of the first set S1 was about 1 mm.

[0180] Each of the first set S1 and second set S2 comprised a second dipole magnet (132a and 132b), each being a bar dipole magnet having a length (L13) of about 20 mm, a width (L14) of about 4 mm and a thickness (L15) of about 2 mm. The second dipole magnets (132a and 132b) were made of NdFeB N45. The distance (d4) between the second dipole magnets (132a and 132b) and the first bar dipole magnets (131 a and 131 a’; 131 b and 131 b’) was about 0.5 mm. The distance (d5) between the edge of the second dipole magnets (132a and 132b) and the edge of the non-magnetic supporting matrix (135) was about 7.5 mm.

[0181] Each of the second bar dipole magnet (132a, 132b) was centrally arranged between the two first bar dipole magnets (131 a and 131 a’; 131 b and 131 b’) of the corresponding set with their magnetic axis being substantially perpendicular to the first plane and to the substrate (120) surface during the process and with the second bar dipole magnet (132a) of the first set S1 having its South Pole pointing towards the first plane and the substrate (120) surface during the process with the first first bar dipole magnet (131 a) and the second first bar dipole magnet (131 a’) of said first set S1 having their South Poles pointing towards the periphery of the magnetic assembly (130) and the second bar dipole magnet (132b) of the second set S2 having its North Pole pointing towards the first plane with the first first bar dipole magnet (131 b) and the second first bar dipole magnet (131 b’) of said second set S2 having their North Poles pointing towards the periphery of the magnetic assembly (130).

[0182] The first bar dipole magnets (131 a and 131 a’; 131 b and 131 b’) and the second bar dipole magnets (132a, 132b) were embedded in the square-shaped non-magnetic supporting matrix (135) so that the uppermost surface of said magnets were flush with the uppermost surface of the non-magnetic supporting matrix (135).Magnetic assembly (130) of Fig. 2B (examples E4-E5)

[0183] The magnetic assembly (130) of Fig. 2B comprised the square-shaped non-magneticSICPA HOLDING SA 272 626 t8 supporting matrix (135) described hereabove, the first set S1 and second set S2 comprising a first first bar dipole magnet (131 a; 131 b) and a second first bar dipole magnet (131 a’; 131 b’) as described hereabove for Fig. 2A.

[0184] Each of the first set S1 and second set S2 comprised a second dipole magnet (132a and 132b), each one being a disc-shaped dipole magnet made of NdFeB N45 and having a diameter (L16) of about 2 mm and a thickness (L17) of about 4 mm. Each of the disc-shaped second dipole magnets (132a and 132b) was arranged so that its center was located at a distance (d6) of about 10.5 mm from the edge of the first bar dipole magnets (131 a and 131 a’; 131 b and 131 b’) of the corresponding set, and at a distance (d7) of about 10 mm from the edge of the square-shaped non-magnetic supporting matrix (135).

[0185] The first bar dipole magnets (131 a and 131 a’; 131 b and 131 b’) and the disc-shaped second dipole magnets (132a and 132b) were embedded in the square-shaped non-magnetic supporting matrix (135) so that the uppermost surface of said magnets were flush with the uppermost surface of the nonmagnetic supporting matrix (135).

[0186] The second disc-shaped dipole magnets (132a, 132b) were centrally arranged between the two bar dipole magnets (131 a and 131 a’; or 131 b and 131 b’) of the first and second set S1 and S2 with their magnetic axis being substantially perpendicular to the first plane and to the substrate (120) surface and with their Poles pointing towards the plane and the substrate (120) surface during the process and wherein the second disc-shaped dipole magnet (132a) of the first set S1 had its South Pole pointing towards the first plane and the substrate (120) surface during the process with the first first bar dipole magnet (131 a) and the second first bar dipole magnet (131 a’) of said first set S1 having their South Poles pointing towards the periphery of the magnetic assembly (130) and the second disc-shaped dipole magnet (132b) of the second set S2 having its North Pole pointing towards the first plane with the first first bar dipole magnet (131 b) and the second first bar dipole magnet (131 b’) of said second set S2 having their North Poles pointing towards the periphery of the magnetic assembly (130). .Magnetic assembly (130) of Fig. 2C (example E6)

[0187] The magnetic assembly (130) of Fig. 2C was the same as the magnetic assembly (130) of Fig. 2B except that the distance (d7) between the center of the disc-shaped second dipole magnets (132a and 132b) and the edge of the non-magnetic supporting matrix (135) was about 12.5 mm while the distance (d6) was the same as in the magnetic assembly (130) of Fig. 2B.Magnetic assembly (130) of Fig. 2D (example E7)

[0188] The magnetic assembly (130) of Fig. 2D was the same as the magnetic assembly (130) of Fig. 2B except that the distance (d6) between the center of the disc-shaped second dipole magnets (132a and 132b) and the edge of the first first bar dipole magnets (131 a; 131 b) of the first set S1 and of the second set S2 was about 5.5 mm, while the distance (d7) was the same as in the magnetic assembly (130) of Fig. 2B.Magnetic assembly (130) of Fig. 2E (examples E8-E10)

[0189] The magnetic assembly (130) of Fig. 2E comprised the square-shaped non-magnetic supporting matrix (135) described hereabove, the first set S1 and second set S2 comprising a first first bar dipole magnet (131 a; 131 b) and a second first bar dipole magnet (131 a’; 131 b’) as describedSICPA HOLDING SA 272 626 t8 hereabove for Fig. 2A.

[0190] Each of the first set S1 and second set S2 comprised a combination of five second dipole magnets (132a1-132a5and 132b1-132b5), each one being a disc-shaped dipole magnet as described hereabove for Fig. 2B. The South Pole of the five second dipole magnets (132a1-132a5) of the first set S1 pointed towards the first plane and towards the substrate (120) during the process and the North Pole of the five second dipole magnets (132b1-132b5) of the second set S2 pointed towards the first plane and towards the substrate (120) during the process.

[0191] The five second dipole magnets (132a1-132a5) of the first set S1 were arranged along a first column with their center being aligned with the center of the first bar dipole magnets (131 a and 131 a’) and the five second dipole magnets (132b1-132b5) of the second set S2 were arranged along a second column with their center being aligned with the center of the first bar dipole magnets (131 b and 131 b’) of the second set S2, the first and second columns being substantially parallel to each other.

[0192] The ten second disc-shaped dipole magnets (132a1-5, 132b1-5) of the first set S1 and of the second set S2 had their magnetic axis being substantially perpendicular to the first plane and to the substrate (120) surface during the process, wherein the five second disc-shaped dipole magnets (132a1-5) of the first set S1 had their South Poles pointing towards the first plane and the substrate (120) surface during the process with the first first bar dipole magnet (131 a) and the second first bar dipole magnet (131 a’) of said first set S1 having their South Poles pointing towards the periphery of the magnetic assembly (130) and the five second disc-shaped dipole magnets (132b1-5) of the second set S2 having their North Poles pointing towards the first plane with the first first bar dipole magnet (131 b) and the second first bar dipole magnet (131 b’) of said second set S2 having their North Poles pointing towards the periphery of the magnetic assembly (130).

[0193] The distance (d7) between the center of the disc-shaped second dipole magnets (132a1-132a5, 132b1-132b5) and the edge of the square-shaped non-magnetic supporting matrix (135) was about 10 mm. The distance (d8) between the centers of two neighboring disc-shaped second dipole magnets (132a1-132a2, 132a2-132a3, 132a3-132a4, 132a4-132a5; 132b1-132b2, 132b2-132b3, 132b3-132b4, 132b4- 132b5) was about 2.5 mm. The distance (d9) between each of the first disc-shaped second dipole magnets (132a1; 132b1) and the edge of each of the first first bar dipole magnets (131 a; 131 b) and the distance between each of the fifth disc-shaped second dipole magnet (132a5; 132b5) and the edge of each of the second first bar dipole magnets (131 a’; 131 b’) was about 5.5 mm.Magnetic assembly (130) of Fig. 2F (examples E11-E13, E30-E38)

[0194] The magnetic assembly (130) of Fig. 2F comprised the square-shaped non-magnetic supporting matrix (135) described hereabove, the first set S1 and second set S2 comprising a first first bar dipole magnet (131 a; 131 b) and a second first bar dipole magnet (131 a’; 131 b’) as described hereabove for Fig. 2A.

[0195] Each of the first set S1 and second set S2 comprised a combination of four second dipole magnets (132a1-132a4and 132b1-132b4), each one being a disc-shaped dipole magnet as described hereabove for Fig. 2B. The South pole of the four second dipole magnets (132a1-132a4) of the first set S1 pointed towards the first plane and towards the substrate (120) during the process and the North Pole of the four second dipole magnets (132b1-132b4) of the second set S2 pointed towards the firstSICPA HOLDING SA 272 626 t8 plane and towards the substrate (120) during the process.

[0196] The second dipole magnets (132a1-132a4) of the first set S1 were arranged according to a first virtual square (Q’) having its center being aligned with the center of the first bar dipole magnets (131 a and 131 a’) of the first set S1 and being at a same distance from the first first bar dipole magnet (131 a) and from the second first bar dipole magnet (131 a’). The second dipole magnets (132b1-132b4) of the second set S2 were arranged according to a second virtual square (Q’) having its center being aligned with the center of the first bar dipole magnets (131 b and 131 b’) of the second set S2 and being at a same distance from the first first bar dipole magnet (131 b) and from the second first bar dipole magnet (131 b’). The distances (d8) and (d10) between the centers of two neighboring disc-shaped second dipole magnets of either the first set S1 or of the second set S2 was about 2.5 mm, respectively.

[0197] The eight second disc-shaped dipole magnets (132a1-4, 132b1-4) of the first set S1 and of the second set S2 had their magnetic axis being substantially perpendicular to the first plane and to the substrate (120) surface during the process, wherein the four second disc-shaped dipole magnets (132a1-4) of the first set S1 had their South Poles pointing towards the first plane and the substrate (120) surface during the process with the first first bar dipole magnet (131 a) and the second first bar dipole magnet (131 a’) of said first set S1 having their South Poles pointing towards the periphery of the magnetic assembly (130) and the four second disc-shaped dipole magnets (132b1-4) of the second set S2 having their North Pole pointing towards the first plane and the substrate (120) surface during the process with the first first bar dipole magnet (131 b) and the second first bar dipole magnet (131 b’) of said second set S2 having their North Poles pointing towards the periphery of the magnetic assembly (130).

[0198] The distance (d7) between the center of the disc-shaped second dipole magnets of the first set S1 (132a1, 132a3) and of the second set S2 (132b2, 132b4) and the edge of the non-magnetic supporting matrix (135) was about 8.75 mm. The distance (d9) between the center of the disc-shaped second dipole magnets (132a1, 132a2, 132b1and 132b2) of the first set S1 and of the second set S2 and the edge of the first first bar dipole magnets (131 a and 131 b) and between the center of the disc-shaped second dipole magnets (131 a3, 132a4, 132b3and 132b4) of the first set S1 and of the second set S2 and the edge of the second first bar dipole magnet (131 a’, 131 b’) was about 9.0 mm.Magnetic assembly (130) of Fig. 2G (examples E14-E16)

[0199] The magnetic assembly (130) of Fig. 2G comprised the square-shaped non-magnetic supporting matrix (135) described hereabove, the first set S1 and second set S2 comprising a first first bar dipole magnet (131 a; 131 b) and a second first bar dipole magnet (131 a’; 131 b’) as described hereabove for Fig. 2A.

[0200] Each of the first set S1 and second set S2 comprised a combination of six second dipole magnets (132a1-132a6and 132b1-132b6), each one being a disc-shaped dipole magnet as described hereabove for Fig. 2B.

[0201] The second dipole magnets (132a1-132a6) of the first set S1 were arranged according to a first virtual rectangle (Q”) having its center being aligned with the center of the first bar dipole magnets (131 a and 131 a’) of the first set S1 and being at a same distance from the first first bar dipole magnet (131 a) and from the second first bar dipole magnet (131 a’). The second dipole magnets (132b1-132b6) of theSICPA HOLDING SA 272 626 t8 second set S2 were arranged according to a second virtual rectangle (Q”) having its center being aligned with the center of the first bar dipole magnets (131 b and 131 b’) of the second set S2 and being at a same distance from the first first bar dipole magnet (131 b) and from the second first bar dipole magnet (131 b’).

[0202] The twelve second disc-shaped dipole magnets (132a1-6, 132b1-6) of the first set S1 and of the second set S2 had their magnetic axis being substantially perpendicular to the first plane and to the substrate (120) surface during the process, wherein the six second disc-shaped dipole magnets (132a1-6) of the first set S1 had their South Poles pointing towards the first plane and the substrate (120) surface during the process with the first first bar dipole magnet (131 a) and the second first bar dipole magnet (131 a’) of said first set S1 having their South Poles pointing towards the periphery of the magnetic assembly (130) and the six second disc-shaped dipole magnet (132b1-6) of the second set S2 having their North Pole pointing towards the first plane with the first first bar dipole magnet (131 b) and the second first bar dipole magnet (131 b’) of said second set S2 having their North Poles pointing towards the periphery of the magnetic assembly (130).

[0203] The distances (d8) and (d10) between the centers of two neighboring disc-shaped second dipole magnets of either the first set S1 or of the second set S2 was about 2.5 mm, respectively. The distance (d7) between the center of the disc-shaped second dipole magnets of the first set S1 (132a1, 132a3, 132a5) and of the second set S2 (132b2, 132b4, 132b6) and the edge of the non-magnetic supporting matrix (135) was about 8.75 mm, respectively. The distance (d9) between the center of the disc-shaped second dipole magnets (132a1, 132a2, 132b1and 132b2) of the first set S1 and of the second set S2 and the edge of the first first bar dipole magnets (131 a and 131 b) and the distance between the center of the disc-shaped second dipole magnets (132a5, 132a6, 132b5and 132b6) of the first set S1 and of the second set S2 and the edge of the second first bar dipole magnets (131 a’ and 131 b’) was about 8 mm, respectively.Magnetic assembly (130) of Fig. 3A (examples E17-E19)

[0204] The magnetic assembly (130) of Fig. 3A was the same as the magnetic assembly (130) of Fig. 2A except that it further comprised two third bar dipole magnets (133a and 133b).

[0205] Each of the two third bar dipole magnets (133a and 133b) was made of NdFeB N48 and had a length (L18) of about 25 mm, a width (L19) of about 2 mm and a thickness (L20) of about 5 mm.

[0206] The magnetic axis of the two third bar dipole magnets (133a and 133b) was substantially parallel to the first plane and to the substrate (120) surface during the process, substantially perpendicular to the magnetic axis of the first bar dipole magnets (131 a and 131 a’; 131 b and 131 b’) and substantially perpendicular to the magnetic axis of the second dipole magnets (132a and 132b) and were pointing in a same direction. The third bar dipole magnet (133a) had its South pole pointing toward the periphery and the third bar dipole magnet (133b) had its North Pole pointing toward the periphery or in other words, the third bar dipole magnets (133a) had its North Pole pointing towards the second dipole magnet (132a) of the first set S1 and towards the center of the supporting matrix (135), said neighbouring second dipole magnet (132a) having its South Pole pointing towards the first plane and towards the substrate (120) during the process.

[0207] The distance (d11 ) between the edge along the width of the two third bar dipole magnets (133aSICPA HOLDING SA 272 626 t8 and 133b) and the edge of non-magnetic supporting matrix (135) was about 2.5 mm. The distance (d12) between the edge along the length of the two third bar dipole magnets (133a and 133b) and the edge of non-magnetic supporting matrix (135) was about 1 .5 mm.Magnetic assembly (130) of Fig. 3B (example E20)

[0208] The magnetic assembly (130) of Fig. 3B was the same as the magnetic assembly (130) of Fig. 2B except that it further comprised two third bar dipole magnets (133a and 133b).

[0209] The distance (d6) between the center of the second dipole magnets (132a and 132b) and the edge of the first bar dipole magnets (131 a and 131 a’; 131 b and 131 b’) of the corresponding set was about 10.5 mm. The distance (d7) between the center of the second dipole magnets (132a and 132b) and the edge of the non-magnetic supporting matrix (135) was about 10 mm.

[0210] The two third bar dipole magnets (133a and 133b) were the same third bar dipole magnets and were arranged in the same arrangement as the two third bar dipole magnets (133a and 133b) of the magnetic assembly (130) of Fig. 3A.Magnetic assembly (130) of Fig. 3C (example E21)

[0211] The magnetic assembly (130) of Fig. 3C was the same as the magnetic assembly (130) of Fig. 3B except that the distance (d7) between the center of the second dipole magnets (132a and 132b) and the edge of the non-magnetic supporting matrix (135) was about 5 mm.Magnetic assembly (130) of Fig. 3D (example E22)

[0212] The magnetic assembly (130) of Fig. 3D was the same as the magnetic assembly (130) of Fig. 3B except that the distance (d6) between the center of the second dipole magnets (132a and 132b) and the edge of the first first bar dipole magnets (131 a ; 131 b) of the corresponding set was about 5 mm.Magnetic assembly (130) of Fig. 3E (examples E23-E25)

[0213] The magnetic assembly (130) of Fig. 3E was the same as the magnetic assembly (130) of Fig. 2F except that it further comprised two third bar dipole magnets (133a and 133b).

[0214] The two third bar dipole magnets (133a and 133b) were the same third bar dipole magnets and were arranged in the same arrangement as the two third bar dipole magnets (133a and 133b) of the magnetic assembly (130) of Fig. 3A.Magnetic assembly (130) of Fig. 4B (examples E26-E28)

[0215] The magnetic assembly (130) of Fig. 4B was the same as the magnetic assembly (130) of Fig. 2F except that it further comprised a fourth bar dipole magnet (134).

[0216] The fourth bar dipole magnet (134) was made of NdBFe N45 and had a length (L21) of about 20 mm, a width (L22) of about 4 mm and a thickness (L23) of about 2 mm.

[0217] The magnetic axis of the fourth bar dipole magnet (134) was substantially parallel to the first plane and to the substrate (120) surface during the process and substantially perpendicular to the magnetic axis of the first bar dipole magnets (131a, 131 a’, 131 b and 131 b’) and substantially perpendicular to the magnetic axis of the disc-shaped second dipole magnets (132a1-4and 132b1-4) with its North Pole pointing towards the disc-shaped second dipole magnets (132a1-4) of the first set S1 having their South Pole pointing towards the first plane and the substrate (120) during the process and its South Pole pointing towards the disc-shaped second dipole magnets (132b1-4) of the second set S2SICPA HOLDING SA 272 626 t8 having their North Pole pointing towards the first plane and the substrate (120) during the process.

[0218] The fourth bar dipole magnet (134) was centrally aligned with the non-magnetic supporting matrix (135) surface, the distance (d13) between the edge of the fourth bar dipole magnet along its width and the edge of the non-magnetic supporting matrix (135) being about 5 mm and the distance (d14) between the edge of the fourth bar dipole magnet along its length and the edge of the nonmagnetic supporting matrix (135) being about 14 mm.Magnetic assembly (130) of Fig. 5B (example E29)

[0219] The magnetic assembly (130) of Fig. 5B was the same as the magnetic assembly (130) of Fig. 3E except that it further comprised a fourth bar dipole magnet (134).

[0220] The fourth bar dipole magnet (134) was the same dipole magnet and was arranged in the same arrangement as the fourth bar dipole magnet (134) of the magnetic assembly (130) of Fig. 4B.Magnetic field generating devices (140) of Figs 1 (examples E1-E38)

[0221] The magnetic field generating device (140) was a bar dipole magnet made of NdFeB N52 and having a length (L1) and a width (L2) of about 29.9 mm, and a thickness (L3) of about 3 mm for the examples E1-E29, E35 and E37 and of about 2 mm for the examples E30-E34.

[0222] The magnetic field generating device (140) of the examples E36 and E38 consisted of a combination of ten bar dipole magnets (1411 1°) made of NdFeB N48, each having a length of about 29.9 mm, a width of about 3 mm and a thickness of about 6 mm. The ten bar dipole magnets (1411’10) were stacked together, with their magnetic axis being substantially parallel to the first plane and to the substrate (120) surface during the process and their magnetic direction pointing all in the same direction.Pole piece (150) of Figs 1

[0223] The pole piece (150) had a length (L7) of about 29.5 mm, a width (L8) of about 29.5 mm and a thickness (L9) of about 1 mm and was made of steel (Type S235).

[0224] The magnetic-field generating device (140) was arranged on top of the magnetic assembly (130) which was arranged on top of the pole piece (150) for the examples E1-E34; the magnetic assembly (130) was arranged on top of the magnetic-field generating device (140) which was arranged on top of the pole piece (150) for the examples E35-E38.Non-magnetic wedges (not shown in Figs 1)

[0225] The magnetic apparatus (1000) further comprised two square-shaped non-magnetic wedges (not shown in the Figs 1), one of said non-magnetic wedges being arranged between the magnetic- field generating device (140) and the magnetic assembly (130), and the second one being arranged between the magnetic assembly (130) or the magnetic-field generating device (140) and the pole piece (150). The square-shaped non-magnetic wedges were made of an adhesive film made of PVC / acrylic film and had a length and a width of about 29.5 mm, and a thickness of about 0.22 mm.Engraved plate (160) (Examples E30-E34)

[0226] The engraved plate (160) had a length of about 37.8 mm, a width of about 37.4 mm and a thickness of about 0.9 mm. The engraved plate (160) was disposed in a recess on the top surface of the holding case (170). The distance between the lowermost surface of the engraved plate (160) and the uppermost surface of the magnetic-field generating device (140) was about 1 .4 mm and the distanceSICPA HOLDING SA 272 626 t8 between the substrate (120) and the uppermost surface of the engraved plate (160) was about 0 mm.

[0227] The engraved plate (160) was either an engraved magnetic plate made of Plastoferrite (supplier = Bomatec, Hbri, CH) produced by injection molding (E30-E32), ora soft magnetic plate (from Bomatec, Hbri, CH) made of FeSi3 granules (Catamold® FeSi3 from BASF, soft magnetic iron-silicon alloy having a coercivity He = 73 Am-1and a permeability j Rmax = 5215) injected at about 80 wt-% in polyoxymethylene (POM) (E33-E34).

[0228] The engraved plate (160) comprised a 50-shaped engraved indicium (about 4 mm x 3 mm). The depth of the engraving was about 0.2 mm for the plastoferrite plate (E30-E32) and about 0.7 mm for the soft magnetic plate (E33-E34).Table 2

[0229] The so-obtained OELs of E1-E38 are shown in Fig. 6B. Fig. 6A shows the tilting directions applied to the substrate (120) used for taking the pictures of Fig. 6B. For the examples E1 , E8, E11 ,E14, E17, E23, E26, E30 and E33-E36 prepared with the configuration of the magnetic field generating device (140) shown in the corresponding Figs 1A„ 1 D and 1 E the pictures were taken while tilting the substrate (120) OEL along the “V” direction illustrated in Fig. 6A. For the examples E2-E7, E9, E10, E12, E13, E15, E16, E18-E22, E24, E25, E27-E29, E31 , E32, E37 and E38 prepared with the configuration of the magnetic field generating device (140) shown in the corresponding Figs 1 B,1C, 1F and 1G the pictures were taken while tilting the substrate (120) carrying the OEL along the “H” direction illustrated in Fig. 6A.

Claims

SICPA HOLDING SA 272 626 t8CLAIMS1 . A magnetic device (100) for producing an optical effect layer (OEL) on a substrate (120), said magnetic device (100) being configured for receiving the substrate (120) in an orientation substantially parallel to a first plane and above the first plane, and comprising: a) a magnetic assembly (130) comprising a non-magnetic supporting matrix (135), a first set S1 and a second set S2 at least partially embedded in the non-magnetic supporting matrix (135), each set S1 and S2 independently comprising: a1) a pair of first bar dipole magnets, each pair independently comprising a first first bar dipole magnet (131 a; 131 b) and a second first bar dipole magnet (131 a’; 131 b’) having their magnetic axis substantially parallel to the first plane, the first first bar dipole magnet (131 a) of the first set S1 and the second first bar dipole magnet (131 a’) of the first set S1 having an opposite magnetic direction, and the first first bar dipole magnet (131 b) of the second set S2 and the second first bar dipole magnet (131 b’) of the second set S2 having an opposite magnetic direction, the first first bar dipole magnet (131 a) of the first set S1 and the first first bar dipole magnet (131 b) of the second set S2 having an opposite magnetic direction, and the second first bar dipole magnet (131 a’) of the first set S1 and the second first bar dipole magnet (131 b’) of the second set S2 having an opposite magnetic direction, the first first bar dipole magnets (131 a; 131 b) of the first set S1 and of the second set S2 being both arranged on a side of a virtual quadrangle and the second first bar dipole magnets (131 a’; 131 b’) of the first set S1 and of the second set S2 being both arranged on an opposite side of the virtual quadrangle, the first first bar dipole magnet (131 b) of the second set S2 being arranged at a distance d3 from the first first bar dipole magnet (131 a) of the first set S1 , the second first bar dipole magnet (131 b’) of the second set S2 being arranged at the distance d3 from the second first bar dipole magnet (131 a’) of the first set S1 , and a2) a second dipole magnet (132a; 132b) having a magnetic axis substantially perpendicular to the first plane, the second dipole magnet (132a) of the first set S1 being arranged between the first first bar dipole magnet (131 a) and the second first bar dipole magnet (131 a’) of said first set S1 , the second dipole magnet (132b) of the second set S2 being arranged between the first first bar dipole magnet (131 b) and the second first bar dipole magnet (131 b’) of said second set S2, the second dipole magnet (132a) of the first set S1 and the second dipole magnet (132b) of the second set S2 having an opposite magnetic direction, the second dipole magnet (132a) of the first set S1 having its South Pole pointing towards the first planeSICPA HOLDING SA 272 626 t8 when the first first bar dipole magnet (131 a) and the second first bar dipole magnet (131 a’) of said first set S1 have their South Poles pointing towards the periphery of the magnetic assembly (130) of the magnetic device (100) or the second dipole magnet (132a) of the first set S1 having its North Pole pointing towards the first plane when the first first bar dipole magnet (131 a) and the second first bar dipole magnet (131 a’) of said first set S1 have their North Poles pointing towards the periphery of the magnetic assembly (130) of the magnetic device (100); b) a magnetic-field generating device (140) being a bar dipole magnet having a magnetic axis substantially parallel to the first plane, and c) a pole piece (150), wherein the magnetic-field generating device (140) is arranged on top of the magnetic assembly (130) and the magnetic assembly (130) is arranged on top of the pole piece (150) or wherein the magnetic assembly (130) is arranged on top of the magnetic- field generating device (140) and the magnetic-field generating device (140) is arranged on top of the pole piece (150), and wherein the optical effect layer (OEL) provides an optical impression of two or more loopshaped bodies having their shape and / or size and / or their brightness varying in opposite directions upon tilting the optical effect layer (OEL).

2. The magnetic device (100) according to claim 1 , wherein the magnetic assembly (130) further comprises a pair of a first third bar dipole magnet (133a) and a second third bar dipole magnet (133b) arranged on two substantially parallel sides of the virtual quadrangle lacking the first first bar dipole magnets (131 a and 131 b) and lacking the second first bar dipole magnets (131 a’ and 131 b’), said two substantially parallel sides being substantially perpendicular to the sides of the virtual quadrangle comprising the first first bar dipole magnets (131 a and 131 b) and the second first bar dipole magnets (131 a’ and 131 b’), wherein said third bar dipole magnets (133a, 133b) have a magnetic axis substantially parallel to the first plane and have a same magnetic direction, with the North Pole of the first third dipole magnet (133a) pointing towards the second dipole magnet (132a) of the first set S1 when said second dipole magnet (132a) of the first set S1 has its South Pole pointing towards the first plane or has its South Pole pointing towards the second dipole magnet (132a) of the first set S1 when said second dipole magnet (132a) of the first set S1 has its North Pole pointing towards the first plane.

3. The magnetic device (100) according to claim 1 or 2, wherein the magnetic assembly (130) further comprises a fourth bar dipole magnet (134) arranged on a virtual line of the virtual quadrangle being substantially perpendicular to the sides of the virtual quadrangle comprising the first first bar dipole magnets (131 a; 131 b) and the second first bar dipole magnets (131 a’; 131 b’) and between the first set S1 and the second set S2, said fourth bar dipole magnet (134) having a magnetic axis substantially parallel to the first plane with its North Pole pointing towards the second dipole magnet (132a or 132b) having its South Pole pointing towards the first plane.SICPA HOLDING SA 272 626 t84. The magnetic device (100) according to any one of claims 1 to 3, wherein the magnetic-field generating device (140) has a magnetic axis being substantially parallel to the magnetic axis of the first first bar dipole magnet (131 a) and of the second first bar dipole magnet (131 a’) of the first set S1 and substantially parallel to the magnetic axis of the first first bar dipole magnet (131 b) and of the second first bar dipole magnet (131 b’) of the second set S2.

5. The magnetic device (100) according to any one of claims 1 to 3, wherein the magnetic-field generating device (140) has a magnetic axis being substantially perpendicular to the magnetic axis of the first first bar dipole magnet (131 a) and of the second first bar dipole magnet (131 a’) of the first set S1 and substantially perpendicular to the magnetic axis of the first first bar dipole magnet (131 b) and of the second first bar dipole magnet (131 b’) of the second set S2.

6. The magnetic device (100) according to any one of claims 1 to 5, wherein the magnetic-field generating device (140) consists of a combination of two or more bar dipole magnets (141 a, 141 b, etc.) having their magnetic axis substantially parallel to the first plane and having a same magnetic direction.

7. The magnetic device (100) according to any one of claims 1 to 6, further comprising an engraved plate (160), wherein said engraved plate (160) is arranged on top of the magnetic- field generating device (140) or on top of the magnetic assembly (130).

8. A magnetic apparatus (1000) comprising the magnetic device (100) recited in any one of claims 1 to 7, a holding case (170) and a holding case bottom lid (171), said magnetic apparatus (1000) being configured for receiving the substrate (120) in an orientation substantially parallel to the first plane and above the first plane, wherein said holding case (170) is arranged on top of the magnetic-field generating device (140) or on top of the magnetic assembly (130).

9. The magnetic apparatus (1000) according to claim 8, further comprising an engraved plate (160), wherein said engraved plate (160) is arranged on top of the holding case (170) provided that the magnetic device (100) does not comprise an engraved plate.

10. A use of the magnetic device (100) recited in any of the claims 1 to 7 orthe magnetic apparatus (1000) recited in claim 8 or 9 for producing an optical effect layer (OEL) on a substrate (120).

11. A process for producing an optical effect layer (OEL) on a substrate (120), said process comprising the steps of: i) applying on the substrate (120) a radiation curable coating composition comprising non- spherical magnetic or magnetizable pigment particles, said radiation curable coating composition being in a first state so as to form a coating layer (110); ii) exposing the radiation curable coating composition to a magnetic field of the magnetic device (100) recited in any of claims 1 to 7 or of the magnetic apparatus (1000) recited in claim 8 or 9 so as to magnetically orient at least a part of the non-spherical magnetic or magnetizable pigment particles; iii) at least partially curing the radiation curable coating composition of step ii) to a second state so as to fix the non-spherical magnetic or magnetizable pigment particles in their adopted positions and orientations,SICPA HOLDING SA 272 626 t8 wherein the step iii) is preferably carried out by UV-Vis light radiation curing and / or the step iii) is carried out partially simultaneously with the step ii).

12. The process according to claim 11 , wherein at least a part of the plurality of non-spherical magnetic or magnetizable particles is constituted by non-spherical colorshifting magnetic or magnetizable pigment particles, preferably selected from the group consisting of magnetic th infilm interference pigment particles, magnetic cholesteric liquid crystal pigment particles, interference coated pigment particles comprising a magnetic material and mixtures thereof.

13. The process according to claim 11 or 12, wherein the non-spherical magnetic or magnetizable pigment particles are platelet-shaped magnetic or magnetizable pigment particles and further comprising a step of exposing the coating layer (110) to a dynamic magnetic field of a device so as to bi-axially orient at least a part of the platelet-shaped magnetic or magnetizable pigment particles, said step occurring prior to or at least partially simultaneously with step ii) and before step iii).

14. The process according to claim 11 or 12, wherein the non-spherical magnetic or magnetizable pigment particles are platelet-shaped magnetic or magnetizable pigment particles and wherein step ii) consists of forming an assembly of the substrate (120) carrying the coating layer (110) above the magnetic device (100) or the magnetic apparatus (1000), wherein said assembly is moved through an inhomogeneous magnetic field of a static device so as to bi-axially orient at least a part of the platelet-shaped magnetic or magnetizable pigment particles.

15. A method of manufacturing a security document or article or a decorative element or object, comprising a) providing the security document or article or the decorative element or object, and b) producing the optical effect layer (OEL) with the process recited in any one of claims 11 to 14, so that the optical effect layer (OEL) is comprised by or non the security document or article or the decorative element or object.

Images