RU2788601C2 - Magnetic assemblies, devices, and methods for production of layers with optical effect, containing oriented non-spherical magnetic or magnetizable pigment particles - Google Patents

Abstract

FIELD: information protection.

SUBSTANCE: invention relates to the field of protection of valuable documents and valuable commercial goods from counterfeit and illegal reproduction. On substrate in the form of a protected document or a decorative element, a layer with an optical effect (OEL) is obtained, providing an optical image of half-moon moving and rotating with inclination of the specified substrate. For obtainment of the specified layer with an optical effect, a composition for coating, containing non-spherical magnetic or magnetizable pigment particles, cured under radiation, is applied to a surface of substrate. The specified composition for coating, cured under radiation, is in the first state in the form of a liquid state. The specified composition for coating is subjected to impact of a magnetic field by means of a magnetic assembly for provision of orientation of at least part of non-spherical magnetic or magnetizable pigment particles.

EFFECT: obtainment of protective signs representing on substrate a bright loop-shaped effect drawing attention of a good quality, while the specified protective signs can be easily checked but they are hard to reproduce at an industrial scale, using equipment available for a counterfeiter, and which can be provided in a large number of different shapes and forms.

14 cl, 17 dwg, 3 tbl

Description

FIELD OF TECHNOLOGY TO WHICH THE INVENTION RELATES

[001] The present invention relates to the field of protecting valuable documents and valuable commercial goods from counterfeiting and illegal reproduction. In particular, the present invention relates to optical effect layers (OELs) exhibiting a viewing angle dependent optical effect, magnetic assemblies and devices and methods for producing said OELs, as well as applications of said OELs as anti-counterfeiting agents on documents.

BACKGROUND OF THE INVENTION

[002] It is known in the art to use paints, coating compositions, coatings or layers containing magnetic or magnetizable pigment particles, in particular non-spherical optically variable magnetic or magnetizable pigment particles, for the manufacture of security features and security documents.

[003] Security features, for example, for security documents, can be broken down into "hidden" and "overt" security features. The protection provided by latent security features is based on the concept that such features are hidden, which usually require special equipment and knowledge to detect, while “overt” security features can be easily detected using the naked human senses, for example , such features may be visible and/or tactilely detectable and still be difficult to manufacture and/or replicate. However, the effectiveness of overt security features depends more on being easily recognized as a security feature, since users will only actually perform a security check based on such a security feature if they are aware of its existence and nature.

[004] Coatings or layers containing oriented magnetic or magnetizable pigment particles are disclosed, for example, in US 2570856, US 3676273, US 3791864, US 5630877 and US 5364689. Magnetic or magnetizable pigment particles in coatings allow the creation of magnetically induced images, patterns and /or drawings by applying an appropriate magnetic field, providing a local orientation of the magnetic or magnetizable pigment particles in the uncured coating, followed by hardening of the latter. As a result, specific optical effects are obtained, i.e. fixed magnetically induced images, patterns or drawings, which are highly resistant to forgery. Security features based on oriented magnetic or magnetizable pigment particles can only be made if there is access both to the magnetic or magnetizable pigment particles or the corresponding paint or composition containing these particles, and to the specific technology used to apply said paint or composition and for orienting said pigment particles in the applied paint or composition.

[005] Moving ring effects are designed to be effective security features. Moving ring effects consist of optically illusory images of objects such as bells, cones, balls, circles, ellipses, and hemispheres that appear to move in any x-y direction, depending on the angle of the specified optical effect layer. Methods for obtaining moving ring effects are disclosed, for example, in EP 1710756 A1, US 8343615, EP 2306222 A1, EP 2325677 A2 and US 2013/084411.

[006] WO 2011/092502 A2 discloses an apparatus for capturing moving ring images displaying a ring that appears to move as the viewing angle changes. The disclosed moving ring images can be obtained or created using a device that allows the orientation of magnetic or magnetizable particles using a magnetic field generated by a combination of a soft magnetizable sheet and a spherical magnet, the magnetic axis of which is perpendicular to the plane of the coating layer, and located under the said soft magnetizable sheet.

[007] Prior art moving ring images were typically obtained by aligning magnetic or magnetizable particles according to the magnetic field of only one rotating or static magnet. Since the magnetic field lines of only one magnet usually bend relatively little, i.e., have a small bend, the change in the orientation of magnetic or magnetizable particles along the surface of the OEL is also relatively weak. In addition, the intensity of the magnetic field decreases rapidly with increasing distance from the magnet when only one magnet is used. This makes it difficult to obtain a highly dynamic and well-defined feature by orienting magnetic or magnetizable particles and can lead to visual effects that exhibit blurred ring edges.

[008] WO 2011/092502 A2 discloses Optical Effect Layers (OELs) containing a plurality of magnetically oriented magnetic or magnetizable particles that are dispersed in a coating. The specific magnetic orientation pattern of the disclosed OELs provides the viewer with an optical effect or impression of a loop-like body that moves as the OELs are tilted. The disclosed OELs are produced using a device comprising a soft magnetizable sheet and a spherical permanent magnet whose north-south direction axis is perpendicular to the plane of the coating layer containing the magnetic or magnetizable particles to be oriented.

[009] WO 2014/108404 A2 discloses Optical Effect Layers (OELs) containing a plurality of magnetically oriented non-spherical magnetic or magnetizable particles that are dispersed in a coating. The specific magnetic orientation pattern of the disclosed OELs provides the viewer with an optical effect or impression of a loop-like body that moves as the OELs are tilted. In addition, WO 2014/108404 A2 discloses OELs further showing an optical effect or impression of a protrusion in a loop body caused by a reflection zone in a central region surrounded by a loop body. The exposed protrusion provides the impression of a three-dimensional object, such as a hemisphere, present in a central region surrounded by a loop body.

[0010] WO 2014/108303 A1 discloses Optical Effect Layers (OELs) containing a plurality of magnetically oriented non-spherical magnetic or magnetizable particles that are dispersed in a coating. The particular magnetic orientation pattern of the disclosed OELs provides the viewer with an optical effect or the impression of a plurality of nested loop-like bodies surrounding one common central area, said bodies exhibiting apparent movement depending on the viewing angle. Moreover, WO 2014/108303 A1 discloses OELs further comprising a protrusion that surrounds and partially fills the central area defined by the closest loop body. The exposed protrusion provides the illusion of a three-dimensional object, such as a hemisphere, present in the central region.

[0011] CN 104442055 B and CN 204566894U disclose apparatuses for producing Optical Effect Layers (OELs) containing a plurality of magnetically oriented non-spherical magnetic or magnetizable particles that are dispersed in a coating. The specific magnetic orientation pattern of the disclosed OELs provides the viewer with an optical effect or impression of a loop-like body that moves as the OELs are tilted. The disclosed OELs are produced by means of a device comprising a first magnet and a second magnet, wherein the second magnet encloses the tilted magnetic region of the first magnet via magnetic coupling.

[0012] There is a need for security features that display an eye-catching bright loop-like effect on a good quality substrate, in which said security features can be easily verified but difficult to mass-produce with equipment available to the counterfeiter, and which can be provided in large quantities. variety of shapes and types.

BRIEF DESCRIPTION OF THE INVENTION

[0013] Accordingly, the aim of the present invention is to overcome the above disadvantages of the prior art.

[0014] In a first aspect, the present invention provides a method for producing an optical effect layer (x10) on a substrate (x20), and optical effect layers (OEL) obtained by such a method, said method comprising the steps of:

i) applying to the surface of the substrate (x20) a radiation-curable coating composition comprising non-spherical magnetic or magnetizable pigment particles, said radiation-curable coating composition being in a first state, said first state being a liquid state;

ii) exposing the radiation-curable coating composition to a magnetic field of a magnetic assembly (x00) containing:

a) a first device (x30) generating a magnetic field whose north-south magnetic axis is substantially perpendicular to the surface of the substrate (x20) and which has a length L1;

b) a second device (x40) generating a magnetic field whose north-south magnetic axis is substantially perpendicular to the surface of the substrate (x20) and which has a length L3,

c) flat pole piece (x50) with length L5,

the first device (x30) generating a magnetic field and the second device (x40) generating a magnetic field have the same direction of the magnetic field,

in this case, the first device (x30), which generates a magnetic field, faces the substrate (x20) and is located on top of the pole piece (x50),

while the second device (x40), which generates a magnetic field, faces the environment and is located under the flat pole piece (x50),

the length L1 of the first device (x30) generating a magnetic field is less than the length L3 of the second device (x40) generating a magnetic field,

the length L1 of the first device (x30) generating the magnetic field is less than the length L5 of the flat pole piece (x50), and

the length L3 of the second device (x40) generating the magnetic field is less than the length L5 of the pole piece (x50),

to ensure orientation of at least a portion of the non-spherical magnetic or magnetizable pigment particles; and

iii) at least partially curing the radiation-curable coating composition of step ii) into a second state, fixing the non-spherical magnetic or magnetizable pigment particles in their adopted positions and orientations,

wherein the optical effect layer provides an optical impression of a crescent moon moving and rotating as the substrate containing the optical effect layer (OEL) is tilted.

[0015] In a further aspect, the present invention provides Optical Effect Layers (OELs) obtainable by the method described herein.

[0016] In a further aspect, the use of an Optical Effect Layer (OEL) is contemplated to protect a security document against forgery or falsification, or for decorative applications.

[0017] In a further aspect, the present invention provides a security document or decorative element or object comprising one or more optical effect layers (OELs) described herein.

[0018] In a further aspect, the present invention provides a magnetic assembly (x00), such as those described herein, to obtain an optical effect layer (OEL) (x10) described herein, and using said magnetic assembly (x00) to obtaining an optical effect layer (x10) on the substrate (x20) described in this document.

[0019] In a further aspect, provided herein is a magnetic assembly (x00), such as those described herein, to obtain an optical effect layer (OEL) (x10) described herein, wherein the magnetic assembly (x00) is located in holder (x01) mounted on the transfer device, which is preferably a rotating magnetic cylinder.

[0020] In a further aspect, the present invention provides a printer for producing an optical effect layer (OEL) as described herein on a substrate such as those described herein, the printer comprising at least one of the magnetic assemblies ( x00) described in this document. The printing device described herein comprises a rotating magnetic cylinder containing at least one of the magnetic assemblies (x00) described herein, or a flatbed printing unit containing at least one of the magnetic assemblies (x00) described herein. document.

[0021] In a further aspect, the present invention provides for the use of the printing apparatus described herein to obtain an optical effect layer (OEL) described herein on a substrate such as described herein.

BRIEF DESCRIPTION OF THE DRAWINGS

In FIG. 1 schematically illustrates a magnetic assembly (100) for obtaining an optical effect layer (110) (OEL) on the surface of a substrate (120), wherein the magnetic assembly (100) comprises a) a first device (130) generating a magnetic field, in particular a disc-shaped or a square magnetic field generating device of length L1, b) a second magnetic field generating device (140), in particular a disk-shaped square magnetic field generating device of length L3, and c) a flat pole piece (150), in particular flat square pole piece with length L5.

In FIG. 2 schematically illustrates a cross section of a magnetic assembly (100) enclosed in a holder (101), wherein the magnetic assembly (100) comprises a) a first device (130) generating a magnetic field, in particular a disk-shaped or square-shaped device generating a magnetic field, b ) a second device (140) generating a magnetic field, in particular a disk-shaped or square-shaped device generating a magnetic field, and c) a flat pole piece (150), in particular a flat square-shaped pole piece, and wherein the holder (101) comprises a domed cover ( 102) with a length L21, center thickness L19 and edge thickness L20, with the lower gate (103) having a length L23 and a thickness L22, and an optional wedge 104 having a length L25 and a thickness (L24).

In FIG. 3A-3D show OEL images obtained with the magnetic assembly (100) illustrated in FIG. 1, viewed from different viewing angles, with the first and second magnetic field generating device (130 and 140) being a disk-shaped magnetic field generating device.

In FIG. 3E shows images of the OEL obtained with the magnetic assembly (100) illustrated in FIG. 1, viewed from different viewing angles, with the first and second magnetic field generating device (130 and 140) being a square-shaped magnetic field generating device.

In FIG. 4 schematically illustrates a magnetic assembly (200) for obtaining an optical effect layer (210) (OEL) on the surface of a substrate (220), wherein the magnetic assembly (200) comprises a) a first device (230) generating a magnetic field, in particular a disc-shaped a magnetic field generating device with a length L1, b) a second magnetic field generating device (240), in particular a disk-shaped magnetic field generating device with a length L3, c) a flat pole piece (250), in particular a flat square or disk-shaped a pole piece of length L5, and d) a non-magnetic plate (260), in particular a square-shaped non-magnetic plate.

In FIG. 5A-5C show OEL images obtained with the magnetic assembly (200) illustrated in FIG. 4 when viewed from different viewing angles.

In FIG. 6 schematically illustrates a magnetic assembly (300) for obtaining an optical effect layer (310) (OEL) on the surface of a substrate (320), wherein the magnetic assembly (300) comprises a) a first device (330) generating a magnetic field, in particular a disc-shaped a magnetic field generating device with a length L1, b) a second magnetic field generating device (340), in particular a disk-shaped magnetic field generating device with a length L3, c) a flat pole piece (350), in particular a flat square pole piece with length L5, and d) a non-magnetic plate (360), in particular a square-shaped non-magnetic plate.

In FIG. 7A-7B show OEL images obtained with the magnetic assembly (300) illustrated in FIG. 6 when viewed from different viewing angles.

In FIG. 8 schematically illustrates a magnetic assembly (400) for obtaining an optical effect layer (410) (OEL) on the surface of a substrate (420), wherein the magnetic assembly (400) comprises a) a first device (430) generating a magnetic field, in particular a disc-shaped a magnetic field generating device with a length L1, b) a second magnetic field generating device (440), in particular a disk-shaped magnetic field generating device with a length L3, c) a flat pole piece (450), in particular a flat square pole piece with a length L5, and d) a second flat pole piece (470), in particular a flat square second pole piece with a length L7.

In FIG. 9A shows OEL images obtained with the magnetic assembly (400) illustrated in FIG. 8 when viewed from different viewing angles.

In FIG. 10 schematically illustrates a magnetic assembly (500) for obtaining an optical effect layer (510) (OEL) on the surface of a substrate (520), wherein the magnetic assembly (500) comprises a) a first device (530) generating a magnetic field, in particular a disc-shaped a magnetic field generating device with a length L1, b) a second magnetic field generating device (540), in particular a disk-shaped magnetic field generating device with a length L3, c) a flat pole piece (550), in particular a flat square pole piece with length L5, d) a non-magnetic plate (560), in particular a square-shaped non-magnetic plate, and e) a second flat pole piece (570), in particular a flat square-shaped second pole piece.

In FIG. 11A shows OEL images obtained with the magnetic assembly (500) illustrated in FIG. 10 when viewed from different viewing angles.

In FIG. 12 schematically illustrates a magnetic assembly (600) for producing an Optical Effect Layer (OEL) (610) on the surface of a substrate (620), wherein the magnetic assembly (600) comprises a) a first device (630) generating a magnetic field, in particular a disc-shaped a magnetic field generating device with a length L1, b) a second magnetic field generating device (640), in particular a disk-shaped magnetic field generating device with a length L3, c) a flat pole piece (650), in particular a flat square pole piece with length L5, d) a non-magnetic plate (660), in particular a square-shaped non-magnetic plate, and e) a magnetized plate (x80), in particular a square-shaped magnetized plate containing engraved characters.

In FIG. 13A shows OEL images obtained with the magnetic assembly (600) illustrated in FIG. 12 when viewed from different viewing angles.

In FIG. 14 schematically illustrates a comparative magnetic assembly according to CN 104442055 B and CN 204566894U for obtaining an optical effect layer (710) on the surface of a substrate (720), wherein the magnetic assembly comprises a) a first device (730) generating a magnetic field, in particular a disc-shaped magnetic field generating device, and b) a second magnetic field generating device (740), in particular a disc-shaped magnetic field generating device.

In FIG. 15A shows OEL images obtained with the magnetic assembly illustrated in FIG. 14 when viewed from different viewing angles.

In FIG. 16 schematically illustrates the comparative magnetic assembly of FIG. 6d of WO 2014/108303 A1 to obtain an optical effect layer (810) on the surface of a substrate (820), wherein the magnetic assembly comprises a) a first device (830) generating a magnetic field, in particular a disk-shaped device generating a magnetic field, b) a second device (840) generating a magnetic field, in particular a disc-shaped device generating a magnetic field, c) a non-planar pole piece (890), in particular a disc-shaped pole piece with a U-shaped cross-section, and d) a flat pole piece (891), in particular a flat disk-shaped pole piece.

In FIG. 17A shows OEL images obtained with the magnetic assembly illustrated in FIG. 16 when viewed from different viewing angles.

DETAILED DESCRIPTION

Definitions

[0022] To interpret the meaning of the terms discussed in the description and set forth in the claims, the following definitions should be used.

[0023] In the context of this document, the singular form of an object indicates one or more objects, and optionally limits the object to a single number.

[0024] In the context of this document, the term "approximately" means that the specified amount or value may have a specific defined value or some other value adjacent to it. In general, the term "approximately" denoting a specific value is intended to mean a range within ±5% of the value. As one example, the phrase "about 100" means the range of 100 ± 5, i.e., the range from 95 to 105. In general, when using the term "about", it can be expected that similar results or effects according to the present invention can be obtained in range within ± 5% of the specified value.

[0025] The term "substantially parallel" refers to a deviation of no more than 10° from parallel alignment, and the term "substantially perpendicular" refers to a deviation of no more than 10° from perpendicular alignment.

[0026] In the context of this document, the term "and/or" means that either all or only one of the elements of the specified group may be present. For example, "A and/or B" would mean "only A or only B, or both A and B". In the case of "only A", this term also covers the possibility of the absence of B, i.e. "only A, but not B".

[0027] The term "comprising" in the context of this document is non-exclusive and subject to change. Thus, for example, a moisturizing solution containing compound A may contain other compounds in addition to A. However, the term "comprising" also encompasses, as does its specific embodiment, the more restrictive meanings of "consisting essentially of" and "consisting of" such that, for example, "wetting solution containing A, B and optionally C" also may (mostly) consist of A and B, or (mostly) consist of A, B, and C.

[0028] The term "coating composition" refers to any composition that is capable of forming an optical effect layer (OEL) according to the present invention on a solid substrate and that can be applied preferably, but not exclusively, by a printing method. The coating composition contains at least a plurality of non-spherical magnetic or magnetizable pigment particles and a binder.

[0029] The term "optical effect layer (OEL)" in the context of this document means a layer that contains at least a plurality of magnetically oriented non-spherical magnetic or magnetizable particles and a binder, while the orientation of the non-spherical magnetic or magnetizable particles is fixed or immobilized (fixed / immobilized ) in the binder.

[0030] The term "magnetic axis" means a theoretical line connecting the respective north and south poles of a magnet and passing through said poles. The term does not include any specific direction of the magnetic field.

[0031] The term "magnetic field direction" means the direction of the magnetic field vector along the magnetic field line extending from the north pole on the outside of the magnet to the south pole (see Handbook of Physics, Springer 2002, pp. 463-464).

[0032] The term "curing" is used to refer to a process in which there is an increase in the viscosity of the coating composition in response to impact to give the material a state, i.e. a cured, solidified or solid state, when non-spherical magnetic or magnetizable pigment particles are fixed / immobilized in their current positions and orientations and can no longer move or rotate.

[0033] When the present description relates to "preferred" embodiments/features, combinations of these "preferred" embodiments/features should also be considered as disclosed as long as the given combination of "preferred" embodiments/features is technically relevant.

[0034] In the context of this document, the term "at least" means one or more than one, for example, one, or two, or three.

[0035] The term "security document" refers to a document that is typically protected from forgery or falsification by at least one security feature. Examples of secure documents include, without limitation, documents of value and valuable commercial goods.

[0036] The term "security feature" is used to refer to an image, pattern, or graphic element that can be used for authentication purposes.

[0037] The present invention provides methods for producing an optical effect layer (OEL) on a substrate and optical effect layers (OEL) obtained by these methods, while these methods include the step of i) applying to the surface of the substrate (x20) cured by radiation a coating composition comprising the non-spherical magnetic or magnetizable pigment particles described herein, wherein said radiation-curable coating composition is in a first state.

[0038] The application step i) described herein can be carried out by a coating process, such as, for example, roller and spray coating processes, or by a printing process. Preferably, the application step i) described herein is carried out by a printing process, preferably selected from the group consisting of screen printing, rotogravure printing, flexographic printing, inkjet printing and gravure printing (also referred to in the art as printing with copper plates and engraved steel die embossing), more preferably selected from the group consisting of screen printing, rotogravure printing and flexographic printing.

[0039] Then, in part at or simultaneously with the application of the radiation-curable coating composition described herein to the surface of the substrate described herein (step i)), at least a portion of the non-spherical magnetic or magnetizable pigment particles are oriented ( step ii)) by exposing the radiation-curable coating composition to a magnetic field of the magnetic assembly (x00) described herein, aligning at least a portion of the non-spherical magnetic or magnetizable pigment particles along the magnetic field lines generated by the magnetic assembly (x00) .

[0040] Then, or partially concurrent with the step of orienting/aligning at least a portion of the non-spherical magnetic or magnetizable pigment particles by applying the magnetic field described herein, the orientation of the non-spherical magnetic or magnetizable pigment particles is fixed or immobilized. Thus, it should be noted that the radiation-curable coating composition must be in a first state, i.e., a liquid or pasty state in which the radiation-curable coating composition is wet or soft enough that the non-spherical magnetic or magnetizable pigment particles , dispersed in the radiation-curable coating composition, are free to move, rotate, and/or orient under the influence of a magnetic field, and a second cured (e.g., solid) state in which the non-spherical magnetic or magnetizable pigment particles are fixed or immobilized in their respective positions and orientations.

[0041] Accordingly, methods for producing an optical effect layer (OEL) on a substrate described herein include the step iii) of at least partially curing the radiation-curable coating composition of step ii) into a second state while fixing the non-spherical magnetic or magnetizable pigment particles in their positions and orientations. Step iii) at least partially curing the radiation-curable coating composition may be carried out after or partly simultaneously with the step of orienting/aligning at least a portion of the non-spherical magnetic or magnetizable pigment particles by applying the magnetic field described herein (step ii)) . Preferably, step iii) of at least partially curing the radiation-curable coating composition is carried out partly simultaneously with the step of orienting/aligning at least a portion of the non-spherical magnetic or magnetizable pigment particles by applying the magnetic field described herein (step ii)). By "partially simultaneously" it is to be understood that both steps are partially performed simultaneously, i.e., the execution times of each of the steps partially overlap. In the context described herein, when curing is performed partly simultaneously with the orienting step ii) it should be understood that the curing takes effect after the orienting so that the pigment particles are oriented before the final or partial curing or solidification of the OEL.

[0042] Optical effect layers (OEL) thus obtained provide the viewer with the optical impression of a crescent moon moving and rotating as the substrate containing the optical effect layer (OEL) is tilted.

[0043] The first and second states of the radiation-curable coating composition are obtained by using a specific type of radiation-curable coating composition. For example, components of the radiation-curable coating composition, other than non-spherical magnetic or magnetizable pigment particles, may take the form of an ink or radiation-curable coating composition, such as those used for security purposes, such as banknote printing. The aforementioned first and second states are obtained by using a material that exhibits an increase in viscosity in response to exposure to electromagnetic radiation. Thus, upon curing of the liquid binder material or its transition to a solid state, the specified binder material passes into the second state, in which the non-spherical magnetic or magnetizable pigment particles are fixed in their current positions and orientations and can no longer move or rotate inside the binder material.

[0044] As known to those skilled in the art, the ingredients contained in a radiation-curable coating composition to be applied to a surface, such as a substrate, and the physical properties of said radiation-curable coating composition must meet the requirements of the process used for transferring the radiation-curable coating composition to the surface of the substrate. Therefore, the binder contained in the radiation-curable coating composition described herein is typically selected from those binders known in the art, and the choice depends on the coating or printing process used to apply the curable substrate. exposure to radiation of the coating composition, and the selected radiation curing process.

[0045] In optical effect layers (OELs) described herein, the non-spherical magnetic or magnetizable pigment particles described herein are dispersed in a radiation-curable coating composition containing a cured binder material that fixes/immobilizes orientation non-spherical magnetic or magnetizable pigment particles. The cured binder material is at least partially transparent to electromagnetic radiation in the wavelength range of 200 nm to 2500 nm. Thus, the binder material is, at least in its cured or solid state (also referred to herein as the second state), at least partially transparent to electromagnetic radiation in the wavelength range of 200 nm to 2500 nm, i.e. e. within a wavelength range commonly referred to as the "optical spectrum" and which contains the infrared, visible and UV portions of the electromagnetic spectrum, so that the particles contained in the binder in their cured or solid state, as well as their dependent from the orientation the reflectivity could be perceived through the bonding material. Preferably, the cured binder material is at least partially transparent to electromagnetic radiation in the wavelength range of 200 nm to 800 nm, more preferably 400 nm to 700 nm. In this document, the term "transparent" means that the transmission of electromagnetic radiation through the 20 µm layer of cured binder present in the OEL (not including lamellar magnetic or magnetizable pigment particles, but including all other optional components of the OEL, if such components are present), is at least 50%, more preferably at least 60%, even more preferably at least 70% at the considered wavelength(s). This can be determined, for example, by measuring the transmittance of a test specimen of the cured binder (not including lamellar magnetic or magnetizable pigment particles) in accordance with well-known test methods, such as DIN 5036-3 (1979-11). If the OEL serves as a latent security feature, then technical means will generally be required to detect the (full) optical effect produced by the OEL under appropriate lighting conditions, including a selected wavelength in the invisible region; this detection requires that the wavelength of the incident radiation be chosen outside the visible range, for example, in the near UV range. In this case, it is preferred that the OEL contains luminescent pigment particles exhibiting luminescence in response to a selected wavelength outside the visible spectrum contained in the incident radiation. The infrared, visible and UV parts of the electromagnetic spectrum correspond approximately to the wavelength ranges 700-2500 nm, 400-700 nm and 200-400 nm, respectively.

[0046] As mentioned above herein, the radiation-curable coating composition described herein depends on the coating or printing process used to apply said radiation-curable coating composition and the curing process chosen. Preferably, the curing of the radiation-curable coating composition involves a chemical reaction that is not reversible by simply increasing the temperature (eg, up to 80° C.) that may occur during typical use of an article containing the OEL described herein. The terms "curing" or "curable" refer to processes involving chemical reaction, cross-linking or polymerization of at least one component in the applied radiation-curable coating composition so that it is converted into a polymeric material having a higher molecular weight than the original substances. Radiation curing advantageously leads to an immediate increase in the viscosity of the radiation-curable coating composition after exposure to the curing radiation, thus preventing any further movement of the pigment particles and consequently any loss of information after the magnetic alignment step. Preferably, the curing step (step iii)) is carried out by curing under the influence of radiation, including curing under the influence of UV and visible radiation or curing under the influence of electron beam radiation, more preferably using curing under the influence of UV and visible radiation .

[0047] Thus, suitable radiation-curable coating compositions of the present invention include radiation-curable compositions that can be cured by exposure to UV-visible radiation (hereinafter referred to as UV-visible radiation) or with electron beam radiation (hereinafter referred to as EL radiation). Radiation curable compositions are known in the art and can be found in standard textbooks such as the "Chemistry & Technology of UV & EB Formulation for Coatings, Inks & Paints" series, Volume IV, Formulation, by C. Lowe, G. Webster, S. Kessel and I. McDonald, 1996, 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-visible radiation-curable coating composition.

[0048] Preferably, the UV-visible curable coating composition comprises one or more compounds selected from the group consisting of radical curable compounds and cationic curable compounds. The UV-VIS curable coating composition described herein may be a hybrid system and contain 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 involving radiation activation of one or more photoinitiators that release cationic species such as acids, which in turn initiate curing to react and/or crosslink the monomers and /or oligomers for curing in this way a radiation-curable coating composition. Radical-curable compounds are cured by free-radical mechanisms, typically involving radiation activation of one or more photoinitiators, thereby generating radicals which in turn initiate polymerization to cure the thus radiation-curable coating composition. Depending on the monomers, oligomers, or prepolymers used to form the binder contained in the UV-visible curable coating compositions described herein, various photoinitiators may be used. Suitable examples of free radical photoinitiators are known to those skilled in the art and include, without limitation, acetophenones, benzophenones, benzyl dimethyl ketals, alpha-aminoketones, alpha-hydroxy ketones, phosphine oxides, and phosphine oxide derivatives, as well as mixtures of two or more of these. Suitable examples of cationic photoinitiators are known to those skilled in the art and include, without limitation, onium salts such as organic iodonium salts (eg, diaryloiodonium salts), oxonium (eg, triaryloxonium salts), and sulfonium salts (eg, triarylsulfonium salts), as well as mixtures of the two or more of them. Other examples of photoinitiators used can be found in standard scientific 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, J. V. Crivello & K. Dietliker, edited by G. Bradley and published in 1998 by John Wiley & Sons in association with SITA Technology Limited. In order to achieve effective curing, it may also be advantageous to include the sensitizer together with one or more photoinitiators. Representative examples of suitable photosensitizers include, but are not limited to, isopropylthioxanthone (ITX), 1-chloro-2-propoxythioxanthone (CPTX), 2-chlorothioxanthone (CTX), and 2,4-diethylthioxanthone (DETX), as well as mixtures of two or more of these. The one or more photoinitiators contained in the UV-visible curable coating compositions are preferably present in a total amount of from about 0.1 wt. % to about 20 wt. %, more preferably from about 1 wt. % to about 15 wt. %, while the weight percentage is calculated based on the total weight of the cured under the influence of radiation in the UV and visible region of the coating compositions.

[0049] The radiation-curable coating composition described herein may further comprise one or more marker substances or markers and/or one or more machine-readable materials selected from the group consisting of magnetic materials (other than those described herein lamellar magnetic or magnetizable pigment particles), luminescent materials, electrically conductive materials and infrared absorbing materials. In the context of this document, the term "machine-readable material" refers to a material that exhibits at least one distinguishing property that is not perceptible to the naked eye, and which can be contained in a layer so as to provide a method for authenticating said layer or an article containing said layer by using specific equipment for its authentication.

[0050] 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 colorants and/or one or more additives. . The latter include, but are not limited to, compounds and materials that are used to adjust the physical, rheological, and chemical parameters of the radiation-curable coating composition, such as viscosity (e.g., solvents, thickeners, and surfactants), consistency (e.g., anti-settling agents, fillers and plasticizers), foaming properties (e.g. antifoam agents), lubricating properties (waxes, oils), UV resistance (photo stabilizers), adhesion properties, antistatic properties, storage stability (polymerization inhibitors), etc. Additives, described herein may be present in the radiation-curable coating composition in amounts and forms known in the art, including so-called nanomaterials, in which at least one of the additive sizes is in the range of 1-1000 nm.

[0051] The radiation-curable coating composition described herein contains the non-spherical magnetic or magnetizable pigment particles described herein. Preferably, the non-spherical magnetic or magnetizable pigment particles are present in an amount of from about 2 wt. % to about 40 wt. %, more preferably from about 4 wt. % to about 30 wt. %, with the weight percentage calculated based on the total weight of the radiation-curable coating composition containing the binder, non-spherical magnetic or magnetizable pigment particles, and other optional components of the radiation-curable coating composition.

[0052] The non-spherical magnetic or magnetizable pigment particles described herein are defined as having, due to their non-spherical shape, anisotropic reflectivity to incident electromagnetic radiation, to which the cured or set binder material is at least partially transparent. In the context of this document, the term "anisotropic reflectivity" means that the proportion of incident radiation at the first angle reflected by the particle in some direction (view) (the second angle) depends on the orientation of the particles, i.e., that the change in the orientation of the particle with respect to the first angle can result in a different amount of reflection in the viewing direction. Preferably, the non-spherical magnetic or magnetizable pigment particles described herein have anisotropic reflectance to incident electromagnetic radiation in some or all of the wavelength range from about 200 to about 2500 nm, more preferably from about 400 to about 700 nm , and at the same time, a change in the orientation of the particle leads to a change in the reflection of this particle in a certain direction. As known to the person skilled in the art, the magnetic or magnetizable pigment particles described herein are different from conventional pigments; said conventional pigment particles display the same color for all viewing angles, while the magnetic or magnetizable pigment particles described herein exhibit anisotropic reflectivity as described herein above.

[0053] Non-spherical magnetic or magnetizable pigment particles are preferably particles in the form of an elongated or flattened ellipsoid, plates or needles, or a mixture of two or more of them, and more preferably plate-like particles.

[0054] Suitable examples of non-spherical magnetic or magnetizable pigment particles described herein include, without limitation, pigment particles containing a magnetic metal selected from the group consisting of cobalt (Co), iron (Fe), gadolinium (Gd), and nickel ( Ni); magnetic alloys of iron, manganese, cobalt, nickel and mixtures of two or more of them; magnetic oxides of chromium, manganese, cobalt, iron, nickel and mixtures of two or more of them; and mixtures of two or more of them. The term "magnetic" in relation to metals, alloys and oxides refers to ferromagnetic or ferrimagnetic metals, alloys and oxides. The magnetic oxides of chromium, manganese, cobalt, iron, nickel, or mixtures of two or more of these, may be pure or mixed oxides. Examples of magnetic oxides include, without limitation, iron oxides such as hematite (Fe ₂ O ₃ ), magnetite (Fe ₃ O ₄ ), chromium dioxide (CrO ₂ ), magnetic ferrites (MFe ₂ O ₄ ), magnetic spinels (MR ₂ O ₄ ), magnetic hexaferrites (MFe ₁₂ O ₁₉ ), magnetic orthoferrites (RFeO ₃ ), magnetic garnets M ₃ R ₂ (AO ₄ ) ₃ , where M is a divalent metal, R is a trivalent metal, and A is a tetravalent metal.

[0055] Examples of non-spherical magnetic or magnetizable pigment particles described herein include, without limitation, pigment particles containing a magnetic layer M made of one or more magnetic metals such as cobalt (Co), iron (Fe), gadolinium (Gd ) or nickel (Ni); as well as a magnetic alloy of iron, cobalt or nickel, while these lamellar magnetic or magnetizable pigment particles can be multilayer structures containing one or more additional layers. Preferably, one or more additional layers are A layers independently made of one or more materials selected from the group consisting of metal fluorides such as magnesium fluoride (MgF ₂ ), silicon oxide (SiO), silicon dioxide (SiO ₂ ) , titanium oxide (TiO ₂ ), zinc sulfide (ZnS) and alumina (Al ₂ O ₃ ), more preferably silicon dioxide (SiO ₂ ); or B layers independently made of one or more materials selected from the group consisting of metals and metal alloys, preferably selected from the group consisting of reflective metals and reflective metal alloys, and more preferably selected from the group consisting of aluminum (Al ), chromium (Cr) and nickel (Ni), and even more preferably aluminum (Al); or a combination of one or more A layers, such as the layers described herein above, and one or more B layers, such as the layers described herein above. Typical examples of lamellar magnetic or magnetizable pigment particles that are multilayer structures described herein above include, without limitation, A/M multilayer structures, A/M/A multilayer structures, A/M/B multilayer structures, A/B multilayer structures. /M/A, multilayer structures A/B/M/B, multilayer structures A/B/M/B/A, multilayer structures B/M, multilayer structures B/M/B, multilayer structures B/A/M/A , B/A/M/B multilayer structures, B/A/M/B/A multilayer structures, wherein the A layers, M magnetic layers, and B layers are selected from those described herein above.

[0056] At least a portion of the non-spherical magnetic or magnetizable pigment particles described herein may be formed by non-spherical optically variable magnetic or magnetizable pigment particles and/or non-spherical magnetic or magnetizable pigment particles that do not have optically variable properties. Preferably, at least a portion of the non-spherical magnetic or magnetizable pigment particles described herein is formed by non-spherical optically variable magnetic or magnetizable pigment particles. In addition to the clear protection afforded by the color changing property of the non-spherical optically variable magnetic or magnetizable pigment particles, which makes it easy to detect, recognize and/or distinguish an article or security document to which an ink has been applied, a radiation-curable coating composition, coating or layer containing the non-spherical optically variable magnetic or magnetizable pigment particles described herein from possible counterfeiting using the naked human senses, the optical properties of the lamellar optically variable magnetic or magnetizable pigment particles can also be used as a machine-readable tool for OEL recognition. Thus, the optical properties of non-spherical optically variable magnetic or magnetizable pigment particles can simultaneously be used as a latent or semi-hidden security feature in an authentication process in which the optical (eg, spectral) properties of the pigment particles are analyzed. The use of non-spherical optically variable magnetic or magnetizable pigment particles in radiation-curable coating compositions for producing OEL increases the value of OEL as a security feature in security document applications because such materials (i.e., non-spherical optically variable magnetic or magnetizable pigment particles) are intended for printing protected documents and are not available for commercial use by an unlimited number of persons.

[0057] Moreover, and due to their magnetic characteristics, the non-spherical magnetic or magnetizable pigment particles described herein are machine-readable, and thus coatings or layers made from the radiation-curable coating compositions described herein and containing these pigment particles can be detected, for example, by means of special magnetic detectors. Thus, the radiation-curable coating compositions containing non-spherical magnetic or magnetizable pigment particles described herein can be used as a hidden or semi-hidden security element (authentication tool) for security documents.

[0058] As noted above, preferably, at least a portion of the non-spherical magnetic or magnetizable pigment particles is formed by non-spherical optically variable magnetic or magnetizable pigment particles. More preferably, they may be selected from the group consisting of non-spherical magnetic thin film interference pigment particles, non-spherical magnetic cholesteric liquid crystal pigment particles, interference-coated non-spherical pigment particles containing magnetic material, and mixtures of two or more of these.

[0059] Magnetic thin film interference pigment particles are known to those skilled in the art and are disclosed, for example, in US 4,838,648; W02002/073250A2; EP 0686675 B1; WO2003/000801A2; US 6838166; WO2007/131833A1; EP 2402401 A1 and in the documents cited therein. Preferably, the magnetic thin film interference pigment particles are pigment particles having a five-layer Fabry-Perot structure and/or pigment particles having a six-layer Fabry-Perot structure and/or pigment particles having a seven-layer Fabry-Perot structure.

[0060] Preferred five-layer Fabry-Perot structures consist of absorber/dielectric/reflector/dielectric/absorber multilayer structures, wherein the reflector and/or absorber is also a magnetic layer, preferably the reflector and/or absorber is a nickel-containing magnetic layer , iron and/or cobalt, and/or a magnetic alloy containing nickel, iron and/or cobalt, and/or a magnetic oxide containing nickel (Ni), iron (Fe) and/or cobalt (Co).

[0061] Preferred six-layer Fabry-Perot structures consist of absorber/dielectric/reflector/magnetic material/dielectric/absorber multilayer structures.

[0062] Preferred seven-layer Fabry-Perot structures consist of absorber/dielectric/reflector/magnetic material/reflector/dielectric/absorber multilayer structures such as those described in US 4,838,648.

[0063] 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 their alloys, even more preferably selected from the group consisting of aluminum (Al), chromium (Cr), nickel (Ni) and their alloys, and even more preferably aluminum (Al). Preferably, the dielectric layers are independently made of one or more materials selected from the group consisting of metal fluorides such as magnesium fluoride (MgF ₂ ), aluminum fluoride (AlF ₃ ), cerium fluoride (CeF ₃ ), lanthanum fluoride (LaF ₃ ) , sodium aluminum fluorides (for example, Na ₃ AlF ₆ ), neodymium fluoride (NdF ₃ ), samarium fluoride (SmF ₃ ), barium fluoride (BaF ₂ ), calcium fluoride (CaF ₂ ), lithium fluoride (LiF), as well as metal oxides such as silicon oxide (SiO), silicon dioxide (SiO ₂ ), titanium oxide (TiO ₂ ), aluminum oxide (Al ₂ O ₃ ), more preferably selected from the group consisting of magnesium fluoride (MgF ₂ ) and silicon dioxide (SiO ₂ ), and even more preferably, magnesium fluoride (MgF ₂ ). Preferably, the absorber layers are independently made of one or more materials selected from the group consisting of aluminum (Al), silver (Ag), copper (Cu), palladium (Pd), platinum (Pt), titanium (Ti), vanadium ( V), iron (Fe), tin (Sn), tungsten (W), molybdenum (Mo), rhodium (Rh), niobium (Nb), chromium (Cr), nickel (Ni), oxides of these metals, sulfides of these metals , carbides of these metals, as well as alloys of these metals, more preferably selected from the group consisting of chromium (Cr), nickel (Ni), oxides of these metals and alloys of these metals, and even more preferably selected from the group consisting of chromium (Cr), nickel (Ni) and alloys of these metals. Preferably, the magnetic layer contains nickel (Ni), iron (Fe) and/or cobalt (Co); and/or a magnetic alloy containing nickel (Ni), iron (Fe) and/or cobalt (Co); and/or a magnetic oxide containing nickel (Ni), iron (Fe) and/or cobalt (Co). If the magnetic thin film interference pigment particles comprising a seven-layer Fabry-Perot structure are preferred, it is particularly preferred that the magnetic thin-film interference particles of a pigment comprise a seven-layer Fabry-Perot absorber/dielectric/reflector/magnetic material/reflector/dielectric/absorber structure consisting of multilayer structure Cr/MgF ₂ /Al/M/Al/MgF ₂ /Cr, where M is a magnetic layer containing nickel (Ni), iron (Fe) and/or cobalt (Co); and/or a magnetic alloy containing nickel (Ni), iron (Fe) and/or cobalt (Co); and/or a magnetic oxide containing nickel (Ni), iron (Fe) and/or cobalt (Co).

[0064] The magnetic thin film interference pigment particles described herein may be multilayer pigment particles that are considered safe for human health and the environment and are based on, for example, five-layer Fabry-Perot structures, six-layer Fabry-Perot structures, and seven-layer Fabry-Perot structures, wherein said pigment particles comprise one or more magnetic layers containing a magnetic alloy having a substantially nickel-free composition comprising from about 40 wt. % to about 90 wt. % iron, from about 10 wt. % to about 50 wt. % chromium and from about 0 wt. % to about 30 wt. % aluminium. Typical examples of multilayer pigment particles that are considered safe for human health and the environment can be found in EP 2402401 A1, which is incorporated herein by reference in its entirety.

[0065] The magnetic thin film interference pigment particles described herein are typically produced by conventional techniques for depositing various desired layers onto a web. After the required number of layers have been deposited, for example by physical vapor deposition (PVD), chemical vapor deposition (CVD), or electroplating, the stack of layers is removed from the web either by dissolving the release layer in a suitable solvent or by stripping material from the web. The material thus obtained is then broken down into lamellar pigment particles, which must be further processed by crushing, grinding (such as, for example, jet milling processes), or any suitable method designed to obtain pigment particles of the desired size. The resulting product consists of flat lamellar pigment particles with jagged edges, irregular shapes and various size ratios. Further information on the preparation of suitable lamellar magnetic thin film interference pigment particles can be found, for example, in EP 1710756A1 and EP 1666546A1, which are incorporated herein by reference.

[0066] Suitable magnetic cholesteric liquid crystal pigment particles exhibiting optically variable characteristics include, without limitation, magnetic single layer cholesteric liquid crystal pigment particles and magnetic multilayer cholesteric liquid crystal pigment particles. Such pigment particles are disclosed in WO 2006/063926 A1, US 6582781 and US 6531221, for example. , such as magnetization. The disclosed monolayers and pigment particles, which are obtained from them by grinding said monolayers, include a three-dimensionally cross-linked cholesteric liquid crystal mixture and magnetic nanoparticles. US 6,582,781 and US 6,410,130 disclose cholesteric multilayer pigment particles that contain the sequence A ¹ /B/A ² , where A ¹ and A ² may be identical or different and each contains at least one cholesteric layer and B is an intermediate layer that absorbs all or some of the light transmitted by layers A ¹ and A ² and provides magnetic properties to the specified intermediate layer. US 6,531,221 discloses lamellar cholesteric multilayer pigment particles containing the sequence A/B and optionally C, where A and C are absorbent layers containing pigment particles that impart magnetic properties to them, and B is a cholesteric layer.

[0067] Suitable interference coated pigments containing 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 one or more layers has magnetic properties. For example, suitable interference coated pigments comprise a core made of a magnetic material such as those described herein above, said core being coated with one or more layers made of one or more metal oxides, or having a structure consisting of a core, made of synthetic or natural mica, layered silicates (eg talc, kaolin and sericite), glasses (eg borosilicates), silicon dioxide (SiO ₂ ), aluminum oxides (Al ₂ O ₃ ), titanium oxides (TiO ₂ ), graphites and mixtures of two or more of them. Moreover, one or more additional layers, such as coloring layers, may be present.

[0068] The non-spherical magnetic or magnetizable pigment particles described herein may be surface treated to protect them from any damage that may occur in a radiation-curable coating composition and/or to facilitate their incorporation into a curable coating composition. irradiated coating composition; typically, anti-corrosion materials and/or wetting agents can be used.

[0069] A method for producing Optical Effect Layers (x10) described herein on a substrate (x20) described herein comprises the step of ii) exposing a radiation-curable coating composition to a magnetic field of a magnetic assembly ( x00) described in this document. Also described herein are magnetic assemblies (x00) and methods using said magnetic assemblies (x00) to obtain an OEL (x10) such as those described herein on a substrate (x20) described herein, said OEL comprising non-spherical magnetic or magnetizable pigment particles oriented in a cured radiation-curable coating composition such as described herein.

[0070] The magnetic assembly (x00) comprises a) a first magnetic field generating device (x30) with a length L1 described herein, b) a second magnetic field generating device (x40) with a length L3 described herein , and c) a flat pole piece (x50) with a length L5 as described in this document.

[0071] According to one embodiment, the magnetic assembly (x00) described herein is disposed or enclosed in a holder (x01) mounted on a transfer device, said transfer device being a rotating magnetic cylinder or magnetic print unit for orientation . Preferably, the magnetic assembly (x00) described herein is located or enclosed in a holder (x01) described herein, said holder (x01) being mounted on a rotating magnetic cylinder, in particular mounted on annular grooves or transverse grooves of a rotating magnetic cylinder.

[0072] As illustrated in FIG. 2, the magnetic assembly (x00) for obtaining the optical effect layer described herein is preferably disposed or enclosed in a holder (x01) described herein, said holder (x01) comprising a domed cover (x02) (i.e. e. curved cover) to protect the magnetic assembly (x00) from dirt and mechanical damage and to provide a smooth surface to hold the substrate (x20) bearing the OEL (x10). The holder (101) and the dome cover (102) have a length and width L21, a thickness L19 at the center of the dome cover (102) and a thickness L20 at the edge of the dome cover (102). The top surface of the domed cover (102) is a curved surface whose curvature is a circle with a radius (L-R). The outer top surface of the dome lid (x02) preferably bears unhindered on the outer surface of the transfer device described herein, preferably on the outer surface of the rotating magnetic cylinder described herein, while the magnetic assembly (x00) described herein is located or enclosed. The domed cover (x02) serves as a separating element between the magnetic assembly (x00) and the substrate (x20) carrying the OEL (x10). As illustrated in FIG. 2, the domed cover (102) may further comprise a recess for securely aligning the first magnetic field generating device (130) with the second magnetic field generating device (140) and flat pole piece (150).

[0073] The holder (x01) described herein includes a bottom gate (x03) to protect the magnetic assembly (x00) from contamination and mechanical damage. The bottom gate (103) has a length and width of L23 and a thickness of L24. The bottom shutter (x03) can be inserted into the bottom surface of the dome cover (x02) to be flush with the bottom surface of the dome cover (x02).

[0074] The domed cover (x02) and the bottom closure (x03) of the holder (x01) described herein are independently made from one or more non-magnetic materials selected from the same group of low conductivity materials, non-conductive materials, and mixtures thereof, such that and for the non-magnetic materials described in this document for the non-magnetic plate (x60).

[0075] The holder (x01) described herein may further comprise a non-magnetic wedge (x04) to support the magnetic assembly (x00) and change the distance A1 from the top surface of the magnetic assembly (x00) to the substrate (x20) bearing the OEL (110 ). The non-magnetic wedge (104) is L25 long and L24 thick. The non-magnetic wedge (x04) described herein is made from one or more non-magnetic materials selected from the same group of low conductivity materials, non-conductive materials, and mixtures thereof as the non-magnetic materials described herein for the non-magnetic plate (x60 ). Advantageously, the domed cap (x02) and the non-magnetic wedge (x04) provide an acceptable distance between the magnetic assembly (x00) and the substrate (x20) in contact with the domed cap (x02).

[0076] The holder (x01) described herein may further comprise a non-magnetic matrix (x41) for securely aligning the second magnetic field generating device (x40) with the first magnetic field generating device (x30) and flat pole piece ( x50). The non-magnetic matrix (x41) typically includes a cavity suitable for receiving a second magnetic field generating device (x40), said cavity being preferably the same shape and size as the second magnetic field generating device (x40). The non-magnetic matrix (x41) described herein is made from one or more non-magnetic materials selected from the same group of low conductivity materials, non-conductive materials, and mixtures thereof as the non-magnetic materials described herein for the non-magnetic plate (x60 ).

[0077] The north-south magnetic axis of each of the first magnetic field generating device (x30) and the second magnetic field generating device (x40) is substantially perpendicular to the surface of the substrate (x20), and both of said first device ( x30) generating a magnetic field and said second device (x40) generating a magnetic field have the same magnetic field direction, i.e. either the north pole of both of said first device (x30) generating a magnetic field and said second device ( x40) that generates a magnetic field points towards the substrate (x20) (as shown in Fig. 1-6), or whose south pole points towards the surface of the substrate (x20).

[0078] The first magnetic field generating device (x30) is located on top of the second magnetic field generating device (x40) at a non-zero distance A2 (i.e., the first and second magnetic field generating devices (x30, x40) are not in direct contact) because at least the flat pole piece (x50) described herein is located between the first magnetic field generating device (x30) and the second magnetic field generating device (x40). As shown in FIG. 1-6, the first magnetic field generating device (x30) faces the surface of the substrate (x20), and the second magnetic field generating device (x40) faces the environment.

[0079] Since the flat pole piece (x50) is located between the first magnetic field generating device (x30) and the second magnetic field generating device (x40), said first magnetic field generating device (x30) is not in direct contact with the specified second device (x40) generating a magnetic field. The distance A2 from the bottom surface of the first magnetic field generating device (x30) to the top surface of the second magnetic field generating device (x40) is preferably about 1 to about 15 mm, and more preferably about 1 to about 10 mm.

[0080] The distance (A1) from the top surface of the first magnetic field generating device (x30) to the bottom surface of the substrate (x20) facing the magnetic assembly (x00) described herein is preferably about 0 to about 5 mm , more preferably from about 0 to about 2.5 mm, and even more preferably from about 0 to about 1 mm.

[0081] The first magnetic field generating device (x30) and the second magnetic field generating device (x40) may have any shape or may have a different shape. The second magnetic field generating device (x40) may be a loop-shaped magnetic field generating device, such as an annular magnetic field generating device, or a solid magnetic field generating device (i.e., a magnetic field generating device that does not contain central region free of the material of said magnetic field generating device). Preferably, the magnetic field generating device (x30) and the second magnetic field generating device (x40) are independently disk-shaped (referred to herein as a "disk-shaped" magnetic field generating device) or parallelepiped-shaped, preferably square-shaped ( referred to in this document as a "square" magnetic field generating device). Preferably, the first magnetic field generating device (x30) and/or preferably the second magnetic field generating device (x40) are disk-shaped magnetic field generating devices or square-shaped magnetic field generating devices. According to a preferred embodiment, the magnetic field generating device (x30) and the second magnetic field generating device (x40) are disk-shaped magnetic field generating devices. According to another preferred embodiment, the magnetic field generating device (x30) and the second magnetic field generating device (x40) are square-shaped magnetic field generating devices. For embodiments incorporating disc-shaped magnetic field generating devices (x30, x40), the lengths L1 and L3 described herein refer to and correspond to the diameter of said disc-shaped devices. For embodiments incorporating square magnetic field generating devices (x30, x40), the lengths L1 and L3 described herein refer to and correspond to the width of said square devices.

[0082] The first magnetic field generating device (x30) has a length L1 (diameter L1 in the case of a disk-shaped magnetic field generating device, or a width L1 in the case of a square-shaped magnetic field generating device) that is less than a length L3 (diameter L3 in the case of disk-shaped magnetic field generating device, or width L3 in the case of a square-shaped magnetic field generating device) of the second magnetic field generating device (x40).

[0083] The first magnetic field generating device (x30) described herein may be arranged symmetrically or asymmetrically with the second magnetic field generating device (x40) described herein. Preferably, and for reasons of mechanical stability, the first magnetic field generating device (x30) described herein is arranged symmetrically with the second magnetic field generating device (x40) described herein, or in other words, the first and second devices ( x30, x40) magnetic field generating devices described in this document are center aligned.

[0084] In a preferred embodiment, and for reasons of mechanical stability, the magnetic assembly (x00) described herein comprises a first magnetic field generating device (x30) which is a disk-shaped magnetic field generating device and a second magnetic field generating device (x40 ) generating a magnetic field, which is a disk-shaped device generating a magnetic field, while the first disk-shaped device (x30) generating a magnetic field is symmetrically located on top of the second disk-shaped device (x40) generating a magnetic field, i.e. the starting point or center (i.e., the intersection point of the diameters) of the first disk-shaped magnetic field generating device (x30) is aligned with the origin of the second disk-shaped magnetic field generating device (x40) (see Figs. 1-6).

[0085] According to another preferred embodiment, and for reasons of mechanical stability, the magnetic assembly (x00) described herein comprises a first magnetic field generating device (x30) which is a square-shaped magnetic field generating device and a second device ( x40) generating a magnetic field, which is a square-shaped device generating a magnetic field, while the first square-shaped device (x30) generating a magnetic field is symmetrically located on top of the second square-shaped device (x40) generating a magnetic field, i.e., the starting point or the center (i.e., the intersection point of the diagonals) of the first square magnetic field generating device (x30) is aligned with the origin of the second square magnetic field generating device (x40) (see FIG. 1).

[0086] The first magnetic field generating device (x30) and the second magnetic field generating device (x40) are preferably independently made of high coercive force materials (also referred to as strong magnetic materials). Suitable high coercive force materials are materials having a maximum energy product (BH) _max of at least 20 kJ/m ³ , preferably at least 50 kJ/m ³ , more preferably at least 100 kJ/m ³ , even more preferably at least 200 kJ/m ³ . They are preferably made from one or more sintered or polymer-bonded magnetic materials selected from the group consisting of alnico, such as, for example, alnico 5 (R1-1-1), alnico 5 DG (R1-1-2), alnico 5-7 (R1-1-3), Alnico 6 (R1-1-4), Alnico 8 (R1-1-5), Alnico 8 HC (R1-1-7) and Alnico 9 (R1-1-6 ); hexaferrites according to the formula MFe ₁₂ O ₁₉ , (for example, strontium hexaferrite (SrO * 6Fe ₂ O ₃ ) or barium hexaferrites (BaO * 6Fe ₂ O ₃ )), magnetically hard ferrites according to the formula MFe ₂ O ₄ (for example, as cobalt ferrite (CoFe ₂ O ₄ ) or magnetite (Fe ₃ O ₄ )), where M is a divalent metal ion), ceramics 8 (SI-1-5); rare earth magnetic materials selected from the group consisting of RECo ₅ (where RE = Sm or Pr), RE ₂ TM ₁₇ (where RE = Sm, TM = Fe, Cu, Co, Zr, Hf), RE ₂ TM ₁₄ B (where RE = Nd, Pr, Dy, TM = Fe, Co); anisotropic alloys Fe Cr Co; materials selected from the group of PtCo, MnAlC, RE cobalt 5/16, RE cobalt 14. Preferably, the high coercive force materials of the first magnetic field generating device (x30) and the second magnetic field generating device (x40) are selected from groups consisting of rare earth magnetic materials and, more preferably, the group consisting of Nd ₂ Fe ₁₄ B and SmCo ₅ . Particularly preferred are easily processed permanent magnet composites containing a permanent magnet filler such as strontium hexaferrite (SrFe ₁₂ O ₁₉ ) or neodymium-iron-boron (Nd ₂ Fe ₁₄ B) powder in a plastic or rubber matrix.

[0087] The magnetic assembly (x00) described herein comprises c) the flat pole piece (x50) described herein. By "flat" is meant that said pole piece does not contain any protrusions or projections protruding outside the surface of said pole piece, i.e. it does not have any protrusions or projections protruding outside the surface of said pole piece. In FIG. 1-6 illustrate magnetic assemblies (x00) containing a flat pole piece (x50), while comparative Fig. 8 illustrates a magnetic assembly comprising a non-planar pole piece (x90), in particular pole pieces having a barb and a U-shaped cross section, and a flat pole piece (x91).

[0088] The flat pole piece (x50) described herein is located between the first device (x30) generating a magnetic field and the second device (x40) generating a magnetic field, or in other words, the first device (x30) generating a magnetic field located on top of the flat pole piece (x50), and a second device (x40) generating a magnetic field is located under the flat pole piece (x50). The flat pole piece (x50) may be in direct contact with the first and second magnetic field generating devices (x30, x40) or may be separated from the first and second magnetic field generating devices (x30, x40).

[0089] The term "pole piece" means a structure consisting of a material having a high absolute magnetic permeability, preferably an absolute magnetic permeability of from about 2 to about 1,000,000 N ^. A ^-2 (newtons per ampere squared), more preferably from about 5 to about 50,000 N ^. A ^-2 and, even more preferably, from about 10 to about 10,000 N ^. A ^-2 . The pole piece serves to guide the magnetic field generated by the magnets. The flat pole piece (x50) described herein may be made of iron or of a plastic material in which magnetizable particles are dispersed. Preferably, the flat pole piece (x50) described herein is made of iron.

[0090] The flat pole piece (x50) is a solid flat pole piece, and more preferably a flat disc-shaped pole piece or a flat square pole piece.

[0091] The flat pole piece (x50) described herein has a length L5, said length L5 being greater than the length L3 of the second magnetic field generating device (x40). For embodiments incorporating a flat disc-shaped pole piece (x50), the length L5 described herein refers to and corresponds to the diameter of said pole piece (x50). For embodiments incorporating a flat square pole piece (x50), the length L5 described herein refers to and corresponds to the width of said pole piece.

[0092] The flat pole piece (x50) may be positioned symmetrically or asymmetrically with the first magnetic field generating device (x30) described herein and the second magnetic field generating device (x40) described herein. Preferably, and for reasons of mechanical stability and design purposes, the flat pole piece (x50) is positioned symmetrically with the first magnetic field generating device (x30) described herein and with the second magnetic field generating device (x40) described in this document.

[0093] According to one embodiment shown in FIG. 1 and 2 and 3A-3D, the magnetic assembly (100) described herein comprises a) a first magnetic field generating device (130), in particular a first disk-shaped magnetic field generating device (130) described herein, b) a second magnetic field generating device (140), preferably a second disk-shaped magnetic field generating device (140) as described herein, and c) a flat pole piece (150), preferably a flat square pole piece (150) as described in this document; wherein the north-south magnetic axis of the first and second disk-shaped magnetic field generating devices (130, 140) is substantially perpendicular to the surface of the substrate (120) and their north pole points towards the substrate (120); the diameter (L1) of the first disk-shaped device (130) generating a magnetic field is less than the diameter (L3) of the second disk-shaped device (140) generating a magnetic field, and the diameter (L3) of the second disk-shaped device (140) generating a magnetic field is less than diameter (L5) of the flat square pole piece (150); wherein the first disk-shaped device (130) generating the magnetic field is in direct contact and located on top of the flat square-shaped pole piece (150); wherein the square-shaped pole piece (150) is in direct contact and located on top of the second disk-shaped device (140) generating a magnetic field; and wherein the reference points (i.e., the intersection point of the diameters) of the first disk-shaped magnetic field generating device (130), the second disk-shaped magnetic field generating device (140), and the flat square pole piece (150) are aligned. Preferably, the distance (A1) from the top surface of the first disc-shaped magnetic field generating device (130) to the bottom surface of the substrate (120) facing the magnetic assembly (100) described herein is preferably about 0 to about 5 mm. , more preferably from about 0 to about 2.5 mm, and even more preferably from about 0 to about 1 mm.

[0094] The magnetic assembly (x00) described herein may further comprise a non-magnetic plate (x60).

[0095] The non-magnetic plate (x60) described herein serves as a separator between the first magnetic field generating device (x30) and the second magnetic field generating device (x40). The non-magnetic plate (x60) described herein is located between the first magnetic field generating device (x30) and the second magnetic field generating device (x40). The non-magnetic plate (x60) described herein may be located under (see, for example, Fig. 4) or may be located on top (see, for example, Fig. 3) of the flat pole piece (x50).

[0096] The non-magnetic plate (x60) described herein is independently made from one or more non-magnetic materials. Non-magnetic materials are preferably selected from the group consisting of low conductivity materials, non-conductive materials and mixtures thereof, such as, for example, engineering plastics and polymers, aluminium, aluminum alloys, titanium, titanium alloys, and austenitic steels (i.e. non-magnetic steels ). Engineering plastics and polymers include, but are not limited to, polyaryletherketones (PAEK) and their derivatives, polyetheretherketones (PEEK), polyetherketone ketones (PEKK), polyetheretherketone ketones (PEEKK), and polyetherketone etherketone ketone (PEKEKK); polyacetals, polyamides, polyesters, polyethers, ester-ether copolymers, polyimides, polyesterimides, high density polyethylene (HDPE), ultra-high molecular weight polyethylene (UHMWPE), polybutylene terephthalate (PBT), polypropylene, acrylonitrile-butadiene-styrene copolymer ( ABS), fluorinated and perfluorinated polyethylenes, polystyrenes, polycarbonates, polyphenylene sulfide (PPS) and liquid crystal polymers. Preferred materials are PEEK (polyetheretherketone), POM (polyoxymethylene), PTFE (polytetrafluoroethylene), Nylon® (polyamide) and PPS.

[0097] The non-magnetic plate (x60) described herein may be of any shape. Preferably, the non-magnetic plate (x60) described herein is a disc-shaped non-magnetic plate or a square-shaped non-magnetic plate, more preferably a square-shaped non-magnetic plate.

[0098] The non-magnetic plate (x60) described herein has a length of L7. For embodiments incorporating a disc-shaped non-magnetic plate (x60), the length L7 described herein refers to and corresponds to the diameter of said non-magnetic plate. For embodiments incorporating a square non-magnetic plate (x60), the length L7 described herein refers to and corresponds to the width of said non-magnetic plate.

[0099] According to the preferred embodiment and for reasons of mechanical stability, the length L7 of the non-magnetic plate (x60) (diameter L7 in the case of a disc-shaped non-magnetic plate; width L7 in the case of a square-shaped non-magnetic plate) is the same as the length L5 of the flat pole piece ( x50).

[00100] The non-magnetic plate (x60) may be arranged symmetrically or asymmetrically with the first magnetic field generating device (x30) described herein, the second magnetic field generating device (x40) and the flat pole piece (x50) described in this document. Preferably, and for reasons of mechanical stability, the non-magnetic plate (x60) is arranged symmetrically with the first magnetic field generating device (x30) described herein, the second magnetic field generating device (x40) and the flat pole piece (x50) described in this document.

[00101] According to one embodiment shown in FIG. 4, the magnetic assembly (200) described herein comprises a) a first magnetic field generating device (230), in particular a first disc-shaped magnetic field generating device (230) described herein, b) a second device (240 ) generating a magnetic field, preferably the second disc-shaped magnetic field generating device (240) described herein, c) a flat pole piece (250), preferably a flat square pole piece or a flat disc-shaped pole piece (250) described herein , and d) a non-magnetic plate (260), preferably a square-shaped non-magnetic plate (260) as described herein; wherein the north-south magnetic axis of the first and second disc-shaped magnetic field generating devices (230, 240) is substantially perpendicular to the surface of the substrate (220) and their north pole points towards the substrate (220); the diameter (L1) of the first disk-shaped device (230) generating a magnetic field is smaller than the diameter (L3) of the second disk-shaped device (230) generating a magnetic field, the diameter (L3) of the second disk-shaped device (230) generating a magnetic field is less than the width (L5) of the flat square pole piece (250) or less than the diameter (L5) of the disc pole piece (250), and the width (L5) of the flat square pole piece (250) or the diameter (L5) of the disc pole piece (250) is the same, like the width (L7) of the square-shaped non-magnetic plate (260); wherein the first disc-shaped magnetic field generating device (230) is in direct contact and is located on top of a flat square-shaped pole piece (250) or a flat disc-shaped pole piece (250); wherein the flat disk-shaped pole piece or the flat square-shaped pole piece (250) is in direct contact and is located on top of the square-shaped non-magnetic plate (260); while the square-shaped non-magnetic plate (260) is in direct contact and is located on top of the second disk-shaped device (240) that generates a magnetic field; and wherein the origins of the first disc-shaped magnetic field generating device (230), the second disc-shaped magnetic field generating device (240), the square-shaped flat pole piece (250) or the disc-shaped pole piece (250) and the square-shaped non-magnetic plate (260) are aligned . Preferably, the distance (A1) from the top surface of the first disc-shaped magnetic field generating device (230) to the bottom surface of the substrate (220) facing the magnetic assembly (200) described herein is preferably about 0 to about 5 mm. , more preferably from about 0 to about 2.5 mm, and even more preferably from about 0 to about 1 mm.

[00102] According to another embodiment shown in FIG. 6, the magnetic assembly (300) described herein comprises a) a first magnetic field generating device (330), in particular a first disc-shaped magnetic field generating device (330) described herein, b) a second device (340 ) generating a magnetic field, preferably a second disc-shaped magnetic field generating device (340) as described herein, c) a flat pole piece (350), preferably a flat square pole piece (350) as described herein, and d) a non-magnetic a plate (360), preferably a non-magnetic square plate (360) as described herein; wherein the north-south magnetic axis of the first and second disk-shaped magnetic field generating devices (330, 340) is substantially perpendicular to the surface of the substrate (320) and their north pole points towards the substrate (320); the diameter (L1) of the first disk-shaped device (330) generating a magnetic field is less than the diameter (L3) of the second disk-shaped device (340) generating a magnetic field, the diameter (L3) of the second disk-shaped device (340) generating a magnetic field is less than the width (L5) of the flat square pole piece (350), and the width (L5) of the flat square pole piece (350) is the same as the width (L7) of the non-magnetic square plate (360); wherein the first disk-shaped device (330) generating the magnetic field is in direct contact and located on top of the square-shaped non-magnetic plate (360); while the square-shaped non-magnetic plate (360) is in direct contact and is located on top of the flat square-shaped pole piece (350); while the flat square-shaped pole piece (350) is in direct contact and is located on top of the second disk-shaped device (340) generating a magnetic field; and wherein the origins of the first disk-shaped magnetic field generating device (330), the second disk-shaped magnetic field generating device (340), the square-shaped flat pole piece (350), and the square-shaped non-magnetic plate (360) are aligned. Preferably, the distance (A1) from the top surface of the first disc-shaped magnetic field generating device (330) to the bottom surface of the substrate (320) facing the magnetic assembly (300) described herein is preferably about 0 to about 5 mm. , more preferably from about 0 to about 2.5 mm, and even more preferably from about 0 to about 1 mm.

[00103] The magnetic assembly (x00) described herein may further comprise a second flat pole piece (x70). The second flat pole piece (x70) described herein is located below the second magnetic field generating device (x40) and thus faces the environment (see FIGS. 8 and 10).

[00104] The second flat pole piece (x70) is a solid flat pole piece and more preferably a flat disc-shaped pole piece or a flat square pole piece and even more preferably the same shape as the flat pole piece (x50).

[00105] The second flat pole piece (x70) is a structure consisting of a material having a high absolute magnetic permeability, such as those described herein for the flat pole piece (x50). Preferably, the second flat pole piece (x70) described herein is made of iron.

[00106] The second flat pole piece (x70) described herein has a length of L9. For embodiments including a second flat disc-shaped pole piece (x70), the length L9 described herein refers to and corresponds to the diameter of said second flat pole piece (x70). For embodiments including a second flat square pole piece (x70), the length L9 described herein refers to and corresponds to the width of said second flat pole piece. According to the preferred embodiment, and for reasons of mechanical stability and design purposes, the length L9 of the second flat square pole piece (x70) is the same as the length L5 of the flat pole piece (x50).

[00107] The second flat pole piece (x70) may be arranged symmetrically or asymmetrically with the first magnetic field generating device (x30) described herein, the second magnetic field generating device (x40), the flat pole piece (x50) described in this document and the non-magnetic plate (x60) described in this document, if available. Preferably, and for reasons of mechanical stability, the second flat pole piece (x70) is positioned symmetrically with the first magnetic field generating device (x30) described herein, the second magnetic field generating device (x40), the flat pole piece (x50), described in this document and the non-magnetic plate (x60) described in this document, if available.

[00108] According to one embodiment shown in FIG. 8, the magnetic assembly (400) described herein comprises a) a first magnetic field generating device (430), in particular a first disc-shaped magnetic field generating device (430) described herein, b) a second device (440 ) generating a magnetic field, preferably a second disc-shaped magnetic field generating device (440) described herein, c) a flat pole piece (450), preferably a flat square pole piece (450) described herein, and d) a second flat pole piece (470), preferably the second flat square pole piece (470) described herein; wherein the north-south magnetic axis of the first and second disc-shaped magnetic field generating devices (430, 440) is substantially perpendicular to the surface of the substrate (420) and their north pole points towards the substrate (420); the diameter (L1) of the first disk-shaped device (430) generating a magnetic field is less than the diameter (L3) of the second disk-shaped device (440) generating a magnetic field, the diameter (L3) of the second disk-shaped device (440) generating a magnetic field is less than the width (L5) of the flat square pole piece (450), and the width (L5) of the flat square pole piece (450) is the same as the width (L7) of the second flat square pole piece (470); wherein the first disk-shaped device (430) generating the magnetic field is in direct contact and located on top of the flat square-shaped pole piece (450); while the flat square-shaped pole piece (450) is in direct contact and is located on top of the second disc-shaped device (440) generating a magnetic field; wherein the second disk-shaped device (440) generating the magnetic field is in direct contact and located on top of the second flat square-shaped pole piece (470); and wherein the origins of the first disk-shaped magnetic field generating device (430), the second disk-shaped magnetic field generating device (440), the square flat pole piece (450), and the second square pole piece (470) are aligned. Preferably, the distance (A1) from the top surface of the first disc-shaped magnetic field generating device (430) to the bottom surface of the substrate (420) facing the magnetic assembly (400) described herein is preferably about 0 to about 5 mm. , more preferably from about 0 to about 2.5 mm, and even more preferably from about 0 to about 1 mm.

[00109] According to one embodiment, the magnetic assembly (x00) described herein comprises a first magnetic field generating device (x30), a second magnetic field generating device (x40) described herein, a flat pole piece (x50) described herein, the non-magnetic plate (x60) described herein, and the second flat pole piece (x70) described herein.

[00110] According to one embodiment shown in FIG. 10, the magnetic assembly (500) described herein comprises a) a first magnetic field generating device (530), in particular a first disc-shaped magnetic field generating device (530) described herein, b) a second device (540 ) generating a magnetic field, preferably a second disk-shaped magnetic field generating device (540) described herein, c) a flat pole piece (550), preferably a flat square pole piece (550) described herein, d) a second flat a pole piece (570), preferably a second flat square pole piece (570) as described herein, and e) a non-magnetic plate (560), preferably a square non-magnetic plate (560) as described herein; wherein the north-south magnetic axis of the first and second disc-shaped magnetic field generating devices (530, 540) is substantially perpendicular to the surface of the substrate (520) and their north pole points towards the substrate (520); the diameter (L1) of the first disk-shaped device (530) generating a magnetic field is less than the diameter (L3) of the second disk-shaped device (540) generating a magnetic field, the diameter (L3) of the second disk-shaped device (540) generating a magnetic field is less than the width (L5) of the flat shaped pole piece (550), and the width (L5) of the flat square pole piece (550) is the same as the width (L7) of the non-magnetic square plate (560), and is the same as the width (L9 - second flat square pole piece (570); wherein the first disk-shaped device (530) generating the magnetic field is in direct contact and located on top of the flat square-shaped pole piece (550); while the flat square-shaped pole piece (550) is in direct contact and is located on top of the non-magnetic square-shaped plate (560); wherein the non-magnetic square-shaped plate (560) is in direct contact and is located on top of the second disk-shaped device (540) generating a magnetic field; wherein the second disk-shaped device (540) generating the magnetic field is in direct contact and located on top of the second flat square-shaped pole piece (570); and while the starting points of the first disk-shaped magnetic field generating device (530), the second disk-shaped magnetic field generating device (540), the square flat pole piece (550), the second flat square pole piece (570) and the non-magnetic square plate (560) are aligned. Preferably, the distance (A1) from the top surface of the first disc-shaped magnetic field generating device (530) to the bottom surface of the substrate (520) facing the magnetic assembly (500) described herein is preferably about 0 to about 5 mm. , more preferably from about 0 to about 2.5 mm, and even more preferably from about 0 to about 1 mm.

[00111] The magnetic assembly (x00) described herein may further comprise a magnetized plate (x80) containing one or more reliefs, engravings and / or cuts on the surface, representing one or more characters, while the specified magnetized plate ( x80) is located on top of the first device (x30) generating a magnetic field, thus facing the substrate (x20) (see Fig. 12). In the context of this document, the term "indicia" means ornaments and designs, including, without limitation, symbols, alphanumeric characters, ornaments, letters, words, numbers, logos, and graphics. One or more reliefs, engravings and/or cuts on the surface of the magnetized plate (x80) contain indicia that are transferred to the OEL in its uncured state by locally modifying the magnetic field generated by the magnetic assembly (x00) described herein. Advantageously, the magnetized plate (x80) may be contained on the top surface of the dome cover (x02) described herein.

[00112] Suitable examples of magnetized plates (x80) containing one or more of the reliefs, engravings and/or cuts on the surface described in this document, for the present invention can be found in documents WO 2005/002866 A1, WO 2008/046702 A1 and WO 2008/139373 A1.

[00113] The magnetized plate (x80) described herein has a length of L11. For embodiments incorporating a square magnetized plate (x80), the length L11 described herein refers to and corresponds to the width of said magnetized plate.

[00114] The magnetized plate (x80) may be arranged symmetrically or asymmetrically with the first magnetic field generating device (x30) described herein, the second magnetic field generating device (x40), the flat pole piece (x50) described herein. document, and the non-magnetic plate (x60) described in this document, if available. Preferably, and for reasons of mechanical stability, the magnetized plate (x80) is positioned symmetrically with the first magnetic field generating device (x30) described herein, the second magnetic field generating device (x40), the flat pole piece (x50) described in herein, the non-magnetic plate (x60) described herein, if any, and the second flat pole piece (x70) described herein, if any.

[00115] The magnetized plate (x80) containing one or more of the engravings and/or cutouts described herein can be made from any permanent magnet machined material, such as permanent magnet composites, containing a permanent magnet powder in malleable metal or polymer matrix. Preferably, the magnetized plate (x80) described herein is a polymer-bonded plate of magnetic material, i.e., a magnetized plate (x80) made from a composite material containing a polymer. The polymer (eg, a rubbery or plastic-like polymer) acts as a structural binder, and the permanent magnet powder material acts as a diluent or filler. Magnetized plates made from a composite material containing a polymer and powder material with a permanent magnet advantageously combine the desired magnetic properties (high coercive force value) of otherwise brittle and difficult to machine ferrites, alnico, rare earth or other magnets with the desired mechanical properties (flexibility, machinability , impact resistance) of malleable metal or plastic material.

[00116] Preferred polymers include rubber-type elastic materials such as nitrile rubbers, EPDM hydrocarbon rubbers, polyisoprenes, polyamides (PA), polyphenylene sulfides (PPS), and chlorosulfonated polyethylenes.

[00117] Preferred permanent magnet powder materials include cobalt, iron and their alloys, chromium dioxide, standard magnet oxide spinels, standard magnetic garnets, standard magnetic ferrites, including hexaferrites such as calcium, strontium, and barium hexaferrite (CaFe12019, SrFe12019, BaFe12019, respectively), standard alloys of alnico, standard alloys of samarium and cobalt (SmCo) and standard alloys of rare earth, iron, boron (such as NdFeB), as well as their permanent magnet chemical derivatives (for example, indicated by the term "standard") and mixtures thereof . Plates made from a composite material containing a polymer and a permanent magnet powder are available from many different suppliers such as Group ARNOLD (Plastiform®) or Materiali Magnetici, Albairate, Milan, Italy (Plastoferrite).

[00118] The magnetized plate (x80) described herein, in particular the magnetized plate (x80) made of a composite material containing a polymer and a permanent magnet powder material described herein, can be obtained in any desired size and shape, for example, in the form of thin, flexible plates that can be bent and machined, such as cut to size or shape, using commonly available mechanical ablation instruments and machines, as well as air or liquid jet ablation instruments, or laser ablation instruments.

[00119] One or more engravings and/or cuts on the surface of a magnetized plate (x80) described herein, in particular a magnetized plate (x80) made from a composite material containing a polymer and a permanent magnet powder material described herein , can be obtained by any cutting or engraving methods known in the art, including, without limitation, casting, molding, hand engraving, or ablation tools selected from the group consisting of mechanical ablation tools (including computer-controlled engraving tools), tools for gaseous or liquid jet ablation, chemical etching, electrochemical etching and laser ablation instruments (eg CO ^2- , Nd-YAG or excimer lasers). As understood by one skilled in the art and described herein, the magnetized plate (x80) described herein, in particular the magnetized plate (x80) made from a composite material containing a polymer and a permanent magnet powder material described herein , also can be cut or molded to a specific size and shape, not engraved. You can cut holes in it or assemble the cut parts on the substrate.

[00120] One or more engravings and cuts on a magnetized plate (x80), in particular a magnetized plate (x80) made of a composite material containing a polymer and a permanent magnet powder material described herein, can be filled with a polymer that can contain fillers. Said filler may be a soft magnetic material to change the magnetic flux at the locations of one or more engravings/cutouts, or it may be any other type of magnetic or non-magnetic material to change the properties of the magnetic field or simply create a smooth surface. The surface of a magnetized plate (x80), in particular the surface of a magnetized plate (x80) made of a composite material containing a polymer and a permanent magnet powder material described herein, can be further treated to facilitate contact with the substrate, reduce friction and/or wear and/or electrostatic charge in a high-speed printing application.

[00121] Preferably, the magnetized plate (x80) described herein is made of a composite material containing the polymer and the permanent magnet powder material described herein, preferably plastoferrite, and contains one or more engravings. The desired high resolution character-shaped pattern is engraved on the plastoferrite plate, either using a mechanical engraving tool or, preferably, using an automatic CO ^2- , Nd-YAG laser engraving tool.

[00122] The magnetized plate (x80) described herein, made of a composite material containing a polymer and a permanent magnet powder material described herein, preferably made of plastoferrite, can be made in the form of a preformed plate and one or more engravings, followed by the application of surface irregularities representing signs according to the specific requirements of use.

[00123] According to one embodiment, the magnetic assembly (x00) described herein comprises a first magnetic field generating device (x30), a second magnetic field generating device (x40) described herein, a flat pole piece (x50) described herein, the non-magnetic plate (x60) described herein, and the magnetized plate (x80) described herein.

[00124] According to one embodiment shown in FIG. 12, the magnetic assembly (600) described herein comprises a) a first magnetic field generating device (630), in particular a first disk-shaped magnetic field generating device (630) described herein, b) a second device (640 ) generating a magnetic field, preferably a second disc-shaped magnetic field generating device (640) as described herein, c) a flat pole piece (650), preferably a flat square pole piece (650) as described herein, d) a non-magnetic plate (660), preferably a square non-magnetic plate (660) as described herein, and e) a magnetized plate (680), preferably a square magnetized plate (680) as described herein; wherein the north-south magnetic axis of the first and second disc-shaped magnetic field generating devices (630, 640) is substantially perpendicular to the substrate (620) and their north pole points towards the substrate (620); a magnetized plate (680), preferably a square magnetized plate (680) as described herein; the diameter (L1) of the first disk-shaped device (630) generating a magnetic field is less than the diameter (L3) of the second disk-shaped device (640) generating a magnetic field, the diameter (L3) of the second disk-shaped device (630) generating a magnetic field is less than the width (L5) of the flat square pole piece (650), the width (L5) of the flat square pole piece (660) is the same as the width (L7) of the non-magnetic square plate (660), and the width (L11) of the square magnetized plate (680) greater than the diameter (L1) of the first disc-shaped magnetic field generating device (630), greater than the diameter (L3) of the second disc-shaped magnetic field generating device (640), greater than the width (L5) of the flat square pole piece (650) and greater than the width (L7) non-magnetic square plate (660); wherein the first disk-shaped device (630) generating the magnetic field is in direct contact and located on top of the flat square-shaped pole piece (650); while the flat square-shaped pole piece (650) is in direct contact and is located on top of the non-magnetic square-shaped plate (660); while the non-magnetic square-shaped plate (660) is in direct contact and is located on top of the second disc-shaped device (640) generating a magnetic field; wherein the square-shaped magnetized plate (680) is in direct contact and is located on top of the first disc-shaped magnetic field generating device (630) and is in direct contact with the substrate (620); and wherein the origin points of the first disk-shaped magnetic field generating device (630), the second disk-shaped magnetic field generating device (640), the square-shaped flat pole piece (650), the square-shaped magnetized plate (680), and the non-magnetic square-shaped plate (660) are aligned .

[00125] Materials of the first device (x30) generating a magnetic field, materials of the second device (x40) generating a magnetic field, materials of flat pole pieces (x50), materials of an optional non-magnetic plate (x60), materials of an optional second flat pole piece (x70) , the materials of the optional magnetized plate (x80) and the distances (A1) and (A2) are chosen so that the magnetic field resulting from the interaction of the magnetic field generated by the magnetic assembly (x00) is suitable for obtaining the optical effect layers described in this document. First magnetic field generating device (x30), second magnetic field generating device (x40), flat pole pieces (x50), optional non-magnetic plate (x60), optional second flat pole piece (x70), and optional magnetized plate (x80) can interact in such a way that the resulting magnetic field of the magnetic assembly (x00) is capable of orienting the non-spherical magnetic or magnetizable pigment particles in the as-yet-cured radiation-curable coating composition on a substrate that are located in the magnetic field of the magnetic assembly to produce the optical impression of a crescent , moving and rotating when the substrate containing the optical effect layer (OEL) is tilted.

[00126] The present invention further provides printing devices comprising a rotary magnetic cylinder transfer device such as those described herein and one or more magnetic assemblies (x00) such as those described herein, wherein said one or more magnetic assemblies (x00) are mounted in the annular grooves of the rotating magnetic cylinder, as well as print units comprising a flatbed print unit transfer device such as those described herein and one or more magnetic assemblies (x00) as described in this document, with the specified one or more magnetic assemblies (x00) installed in the recesses of the flatbed printing unit.

[00127] The rotatable magnetic cylinder is intended to be used in part or in combination with or as part of a printing or coating equipment and includes one or more of the magnetic assemblies described herein. In an embodiment, the rotating magnetic cylinder is part of a rotary, sheet or web fed industrial printing press that operates continuously at high print speeds.

[00128] A flatbed print unit is intended to be used in part or in combination with, or is part of, printing or coating equipment and includes one or more of the magnetic assemblies described herein. In an embodiment, a flatbed print unit is part of an industrial sheet-fed printing press that operates intermittently.

[00129] Printing devices comprising the rotary magnetic cylinder described herein or the flatbed printing unit described herein may include a mechanism for feeding a substrate, such as described herein, coated with a layer of non-spherical magnetic or magnetizable pigment particles described herein, so that the magnetic assemblies generate a magnetic field that acts on the pigment particles to orient them to form an Optical Effect Layer (OEL). In an embodiment of printing devices comprising a rotating magnetic cylinder described herein, the substrate is fed by a mechanism for supplying the substrate in the form of sheets or webs. In an embodiment of printing devices comprising the flatbed print unit described herein, the substrate is supplied in the form of sheets.

[00130] Printing devices comprising the rotary magnetic cylinder described herein or the flatbed printing unit described herein may include a coating or printing unit for applying a radiation-curable coating composition containing non-spherical magnetic or magnetizable pigment particles. described herein onto a substrate described herein, wherein the radiation-curable coating composition comprises non-spherical magnetic or magnetizable pigment particles that are oriented by a magnetic field generated by the devices described herein to form an optical effect layer. (OEL). In an embodiment of printing devices comprising a rotating magnetic cylinder described herein, the coating or printing unit operates in accordance with a rotary continuous process. In an embodiment of printing devices comprising the flatbed printing unit described herein, the coating or printing unit operates in accordance with a longitudinal, discontinuous process.

[00131] Printing devices comprising the rotary magnetic cylinder described herein or the flatbed printing unit described herein may include a curing unit for at least partially curing a radiation-curable coating composition containing non-spherical magnetic or magnetizable particles. pigment that have been magnetically oriented by the devices described herein, thereby fixing the orientation and position of the non-spherical magnetic or magnetizable pigment particles to form an Optical Effect Layer (OEL).

[00132] According to one embodiment, and provided that the non-spherical magnetic or magnetizable pigment particles are lamellar pigment particles, the method for producing an optical effect layer (OEL) described herein may further include the step of exposing a radiation-curable composition to of the coating described herein to the dynamic magnetic field of the first magnetic field generating device in order to biaxially orient at least a portion of the lamellar magnetic or magnetizable pigment particles, said step being carried out after step i) and before step ii). Methods comprising such a step of exposing the coating composition to a dynamic magnetic field of a first magnetic field generating device to biaxially orient at least a portion of the lamellar magnetic or magnetizable pigment particles prior to further exposing the coating composition to a second magnetic field generating device, in In particular, the effects of the magnetic field of the magnetic assembly described herein are disclosed in WO 2015/086257 A1. After exposure of the radiation-curable coating composition to a dynamic magnetic field of the first magnetic field-generating device described herein, and while the radiation-curable coating composition is still wet or soft enough that the lamellar magnetic or magnetizable pigment particles are it could additionally move and rotate, lamellar magnetic or magnetizable pigment particles are further reoriented using the device described in this document.

[00133] The implementation of biaxial orientation means that the orientation of the lamellar magnetic or magnetizable pigment particles is performed in such a way that their two main axes are fixed. Therefore, each lamellar magnetic or magnetizable pigment particle can be considered to have a major axis in the plane of the pigment particle and an orthogonal minor axis in the plane of the pigment particle. Under the influence of a dynamic magnetic field, the orientation of each major and minor axis of lamellar magnetic or magnetizable pigment particles occurs. As such, this results in adjacent lamellar magnetic pigment particles that are spaced close to each other in a substantially parallel arrangement. In order to perform biaxial orientation, lamellar magnetic pigment particles must be subjected to a rapidly changing external magnetic field. In other words, biaxial orientation aligns the planes of lamellar magnetic or magnetizable pigment particles such that the planes of said pigment particles are oriented substantially parallel to the planes of neighboring (in all directions) lamellar magnetic or magnetizable pigment particles. In an embodiment, both the major axis and the minor axis, perpendicular to the major axis previously described herein, of the planes of lamellar magnetic or magnetizable pigment particles are oriented under dynamic magnetic field such that the major and minor axes of neighboring (in all directions) particles pigments are aligned with each other.

[00134] In one embodiment, the step of biaxially aligning the lamellar magnetic or magnetizable pigment particles results in magnetic alignment wherein the lamellar magnetic or magnetizable pigment particles have two major axes substantially parallel to the surface of the substrate. For this alignment, lamellar magnetic or magnetizable pigment particles are planarized in a radiation-curable coating composition on a substrate and oriented along both their X-axis and their Y-axis (shown in Figure 1 of WO 2015/086257 A1), parallel to the surface substrates. In another embodiment, the step of biaxially orienting the lamellar magnetic or magnetizable pigment particles results in magnetic alignment wherein the lamellar magnetic or magnetizable pigment particles have a first axis in the X-Y plane substantially parallel to the surface of the substrate, and a second axis substantially perpendicular to said first axis at a substantially non-zero angle of inclination to the surface of the substrate. In another embodiment, the step of biaxially aligning the lamellar magnetic or magnetizable pigment particles results in magnetic alignment wherein the lamellar magnetic or magnetizable pigment particles have an X-Y plane substantially parallel to the surface of the imaginary spheroid.

[00135] Particularly preferred magnetic field generating devices for biaxially orienting lamellar magnetic or magnetizable pigment particles are disclosed in EP 2 157 141 A1. The magnetic field generating device disclosed in EP 2157141 A1 provides a dynamic magnetic field that changes its direction causing lamellar magnetic or magnetizable pigment particles to oscillate rapidly until both principal axes, the X-axis and the Y-axis, are substantially parallel to the surface. the substrates, i.e. lamellar magnetic or magnetizable pigment particles, are rotated until they form a stable sheet-like structure, with their X and Y axes being substantially parallel to the surface of the substrate and planarized in the two indicated dimensions.

[00136] Other particularly preferred magnetic field generating devices for biaxially orienting lamellar magnetic or magnetizable pigment particles are Halbach assemblies with linear permanent magnets, i.e. assemblies containing a plurality of magnets with different magnetization directions. A detailed description of Halbach permanent magnets has been given by Z.Q. Z.Q. Zhu et D. Howe (Halbach permanent magnet machines and applications: a review, IEE. Proc. Electric Power Appl., 2001, 148, pp. 299-308). The magnetic field generated by such a Halbach assembly has the properties that it is concentrated on one side while attenuating to almost zero on the other side. Pending EP 14195159.0 discloses suitable devices for biaxially orienting lamellar magnetic or magnetizable pigment particles, said devices comprising a Halbach cylinder assembly. Other particularly preferred magnetic field generating devices for biaxially orienting lamellar magnetic or magnetizable pigment particles are rotating magnets, said magnets comprising disk-shaped rotating magnets or magnetic assemblies which are substantially magnetized along their diameter. Suitable rotating magnets or magnetic assemblies are described in US 2007/0172261 A1, wherein said rotating magnets or magnetic assemblies generate radially symmetrical, time-varying magnetic fields allowing for biaxial orientation of lamellar magnetic or magnetizable pigment particles of the uncured or hardened composition. for coverage. These magnets or magnetic assemblies are driven by a shaft (or spindle) attached to an external motor. CN 102529326 B discloses examples of magnetic field generating devices containing rotating magnets that may be suitable for biaxially orienting lamellar magnetic or magnetizable pigment particles. In a preferred embodiment, suitable magnetic field generating devices for biaxially orienting lamellar magnetic or magnetizable pigment particles are non-shaft mounted disk-shaped rotating magnets or magnetic assemblies mounted in a housing made of non-magnetic, preferably non-conductive materials, and are driven by one or more electromagnetic coils wound around the body. Examples of such non-shaft mounted disc-shaped rotating magnets or magnet assemblies are disclosed in WO 2015/082344 A1 and pending EP 14181939.1.

[00137] The substrate described herein is preferably selected from the group consisting of paper or other fibrous materials such as cellulose, paper containing materials, glasses, metals, ceramics, plastics and polymers, metallized plastics or polymers, composite materials and their mixtures or combinations. Typical paper, paper-like, or other fibrous materials are made from a wide variety of fibers, including, without limitation, manila hemp, cotton, flax, wood pulp, and mixtures thereof. As is well known to those skilled in the art, cotton fiber and cotton/linen fiber blends are preferred for banknotes, while wood pulp is generally used for non-banknote security documents. Typical examples of plastics and polymers include polyolefins such as polyethylene (PE) and polypropylene (PP), polyamides, polyesters such as poly(ethylene terephthalate) (PET), poly(1,4-butylene terephthalate) (PBT), poly(ethylene -2,6-naphthoate) (PEN) and polyvinyl chlorides (PVC). The substrate can also be spun olefin fibers, such as those sold under the trademark ^Tyvek® . Typical examples of metallized plastics or polymers include the plastics or polymer materials described herein above, on the surface of which metal is continuously or discontinuously located. Typical examples 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 above metals. . The plating of the plastic or polymeric materials described herein above can be carried out using an electrodeposition process, a high vacuum coating process, or a sputtering process. Typical examples of composite materials include, without limitation, multilayer structures or laminates of paper and at least one plastic or polymeric material, such as those described herein above, as well as plastic and/or polymeric fibers included in a paper-like or fibrous material, such as described above in this document. Of course, the substrate may contain additional additives known to those skilled in the art, such as sizing agents, brighteners, processing aids, reinforcing agents or wet strength agents, etc. The substrate described herein may be in the form of a web (for example, solid sheet from the materials described in this document above) or in the form of sheets. If the OEL obtained according to the present invention will be on a security document, and in order to further increase the level of security and protection against forgery and illegal reproduction of this security document, the substrate may contain printed, coated, or laser marked or laser-perforated marks, watermarks , security threads, fibers, confetti, luminescent compounds, windows, foils, decals and combinations of two or more of these. For the same purpose of further increasing the level of security and protection against forgery and illegal reproduction of protected documents, the substrate may contain one or more marker substances or markers and/or machine-readable substances (for example, luminescent substances, UV/Visible/IR absorbing substances, magnetic substances and their combinations).

[00138] The Optical Effect Layer (OEL) described herein can be applied directly to a substrate where it must remain permanently (eg, for bank note applications). Alternatively, for industrial purposes, an optical effect layer (OEL) can also be applied to a temporary substrate from which the OEL is subsequently removed. This can, for example, facilitate the manufacture of the OEL, in particular while the binder is still in its liquid state. Then, after at least partially curing the coating composition to form an OEL, the temporary OEL support may be removed.

[00139] Alternatively, an adhesive layer may be present on the OEL, or may be present on a substrate containing an Optical Effect Layer (OEL), said adhesive layer being located on the side of the substrate opposite to that of the OEL, or on the the same side as the OEL and on top of the OEL. Therefore, the adhesive layer can be applied to an optical effect layer (OEL) or to a substrate. Such a product can be attached to all types of documents or other products or objects without printing or other processes involving machines and mechanisms and rather high labor costs. Alternatively, the substrate described herein containing the OEL described herein may be in the form of a transfer foil that can be applied to a document or article in a separate transfer step. To this end, the substrate is made with a release coating, on which the OEL is made, as described in this document. One or more adhesive layers can be applied over the thus obtained OEL.

[00140] Also described herein are substrates containing more than one, i.e. two, three, four, etc., optical effect layers (OELs) obtained by the method described herein.

[00141] This document also describes articles, in particular security documents, decorative elements or objects, containing an optical effect layer (OEL) obtained according to the present invention. Articles, in particular security documents, decorative elements or objects, may contain more than one (eg two, three, etc.) OELs obtained according to the present invention.

[00142] As mentioned herein above, the optical effect layer (OEL) obtained according to the present invention can be used for decorative purposes, as well as for protecting and authenticating a security document. Typical examples of decorative items or objects include, but are not limited to, luxury goods, cosmetic packaging, automotive parts, electronic/electrical appliances, furniture, and nail polishes.

[00143] Security documents include, without limitation, documents of value and valuable commercial items. Typical examples of documents of value include, without limitation, banknotes, legal documents, tickets, cheques, vouchers, revenue and duty stamps, agreements, etc., identification documents such as passports, identity cards, visas, driver's licenses, bank cards , credit cards, transaction cards, access documents or cards, entrance tickets, public transport tickets or public transport entitlement documents, etc., preferably banknotes, identity documents, documents, title to ownership, driver's licenses and credit cards. The term "high value commercial item" refers to packaging materials, in particular for cosmetics, nutraceuticals, pharmaceuticals, spirits, tobacco, beverages or foods, electrical/electronic products, fabrics or jewelry, i.e. products that must be protected from counterfeiting and/or illegal reproduction, in order to guarantee the authenticity of the contents of the package, such as genuine medicines. Examples of these packaging materials include, but are not limited to, labels such as product authentication labels, tamper-evident labels and seals. It should be noted that the disclosed substrates, valuable documents, and valuable commercial items are provided by way of example only, without limiting the scope of the present invention.

[00144] Alternatively, an Optical Effect Layer (OEL) may be applied to a secondary substrate such as, for example, a security thread, security strip, foil, decal, window, or label, and then transferred to the security document in a separate step.

EXAMPLES

[00145] The magnetic assemblies illustrated in FIG. 1-12 were used to orient non-spherical optically variable magnetic pigment particles in a printed layer of the UV curable screen printing ink described in Table 1 to produce the optical effect layers (OEL) shown in FIG. 1B–11. Comparative assemblies illustrated in FIG. 14 and 16 were used to orient the non-spherical optically variable magnetic pigment particles in the printed layer of the UV-curable screen printing ink described in Table 1 to obtain the comparative optical effect layers (OEL) shown in FIG. 15A and 17A.

[00146] The UV-curable screen printing ink was applied to black commercial paper (BNP 90 g/m ² standard fiduciary paper, from Papierfabrik Louisenthal, 50 x 50 mm), said application being carried out manually by screen-printed using a T90 screen to form a coating layer (36 mm x 36 mm) about 20 µm thick. A substrate carrying an applied layer of UV-curable screen printing ink was placed on a magnetic assembly. The magnetic alignment pattern of the non-spherical optically variable pigment particles thus obtained was fixed partly simultaneously with the alignment step by UV curing the printed layer containing the pigment particles using a Phoseon UV LED lamp (FireFlex type 50 x 75 mm, 395 nm, ⁸ W/cm2).

Table 1 UV Curable Screen Printing Ink (Coating Composition)

Epoxy acrylate oligomer 28% Trimethylolpropane triacrylate monomer 19.5% Tripropylene glycol diacrylate monomer 20% ^GenoradTM 16 (Rahn) 1% ^Aerosil® 200 (Evonik) 1% Speedcure TPO-L (Lambson) 2% ^IRGACURE® 500 (BASF) 6% Genocure EPD (Rahn) 2% ^Tego® Foamex N (Evonik) 2% Non-spherical optically variable magnetic pigment particles (7 layers)(*) 16.5%

(*) Gold to green color change optically variable magnetic pigment particles shaped like flakes with a d50 diameter of approximately 9 µm and a thickness of approximately 1 µm obtained from Viavi Solutions, Santa Rosa, California.

Devices and materials

[00147] The first magnetic field generating devices (x30) and the second magnetic field generating devices (x40) were made of NdFeB N30. As shown in FIG. 1-12, the magnetic assemblies (x00) independently comprised a first magnetic field generating device (x30) and a second magnetic field generating device (x40), wherein said first magnetic field generating device (x30) was positioned on top of said second device (x40) generating a magnetic field, with the north-south magnetic axis of the two devices (x30, x40) being substantially perpendicular to the surface of the substrate (x20), with the north pole pointing towards the substrate (x20) .

[00148] As shown in FIG. 1-12, the magnetic assemblies (x00) independently comprised a flat pole piece (x50), with said flat pole piece (x50) positioned between the first magnetic field generating device (x30) and the second magnetic field generating device (x40). . Flat pole pieces (x50) were independently made of iron.

[00149] As shown in FIG. 4, 6, 10, and 12, the magnetic assemblies (x00) independently comprised a non-magnetic plate (x60), said non-magnetic plate (x60) being positioned between a first device (x30) generating a magnetic field and a second device (x40) generating a magnetic field. Non-magnetic plates (x60), if available, were independently made from POM.

[00150] As shown in FIG. 8-10, the magnetic assemblies (x00) independently comprised a second flat pole piece (x70), with said second flat pole piece (x70) positioned under the second magnetic field generating device (x40) and facing the environment. The second flat pole pieces (x70), if present, were independently made of iron.

[00151] The magnetized plate (x80) containing the sign in the form of "50" (x80) was made of plastoferrite (TROMAFLEX ^® from Max Baermann GmbH, Bergisch Gladbach). The magnetized plate (x80) was magnetized in the direction perpendicular to the surface of the substrate (x20), and then engraved on a computer-controlled mechanical engraving station with a geometric design (mark "50"), with a size of 2.5 mm x 3.0 mm. The engravings of the square magnetized plate (x80) had an engraving depth of approximately 0.2 mm and a line width of approximately 1 mm). As shown in FIG. 12, the magnetic assemblies (600) independently comprised a magnetized plate (680), said magnetized plate (680) being placed on top of the first magnetic field generating device (630) and under the substrate (620).

[00152] The non-planar pole pieces (x90) and the flat pole piece (x91), if present, were independently made of iron.

[00153] The dimensions and shape of the first magnetic field generating device (x30), the second magnetic field generating device (x40), the flat pole piece (x50), the non-magnetic plate (x60), the second flat pole piece (x70), and the magnetized plate ( x80) of examples E1-E13 are shown in Table 2. The distance A1 from the top surface of the first device (x30) generating the magnetic field to the bottom surface of the substrate (x20) facing the magnetic assembly (x00), and the distance A2 from the top surface of the second device (x40) generating a magnetic field to the lower surface of the first devices (x30) generating a magnetic field, examples E1-E13 are presented in table 2.

[00154] The dimensions and shape of the first magnetic field generating device (x30), the second magnetic field generating device (x40), the flat pole piece (x91) and the non-planar pole piece (x90) of Comparative Examples C1-C2 are shown in Table 3. Distance A1 from the upper surface of the first magnetic field generating device (x30) to the lower surface of the substrate (x20) facing the magnetic assembly (x00), and the distance A2 from the upper surface of the second magnetic field generating device (x40) to the lower surface of the first magnetic field generating device (x30) of comparative examples C1-C2 are shown in Table 3.

[00155] The holders (x01) were independently used to insert the magnetic assemblies (x00) used to prepare Examples 1-13 (E1-E13) and Comparative Examples 1-2 (C1-C2). The holder (101) illustrated in FIG. 2 was used to prepare Example E3, said holder (101) containing a domed cap (102), a bottom closure (103), a non-magnetic wedge (104) and a non-magnetic matrix (141). The holder (101) had a length and width (L21) of approximately 40 mm, a central thickness (L19) of approximately 15.15 mm, an edge thickness (L20) of approximately 14.80 mm. The curvature (L-R) of the top surface of the domed cover (102) was the same as that of a circle with a radius (L-R) of approximately 137.5 mm. The lower closure (103) of the holder (101) had a length and width (L23) of approximately 32 mm and a thickness (L22) of approximately 3 mm. The non-magnetic wedge (104) had a length and width (L25) of approximately 30 mm and a thickness (L24) of approximately 5.8 mm. The holder (101) illustrated in FIG. 2, further comprises a non-magnetic matrix (141) containing a cavity suitable for receiving a second device (140) generating a magnetic field, while said non-magnetic matrix (141) is a square-shaped plate with a length (L25) of approximately 30 mm and a thickness (L4) approximately 2 mm, containing a disc-shaped cavity with a diameter (L3) of approximately 20 mm. The domed lid (102) and bottom closure (103) of the holder (101) were made of polyphenylene sulfide (PPS). The non-magnetic wedge (104) and the non-magnetic die (141) were independently made from POM.

[00156] Examples 1-13 (E1-E13) and Comparative Examples 1-2 (C11-C2) were independently prepared using magnetic assemblies (x00) enclosed in holders (x01) whose external dimensions are the same as those of the holder ( 101) described herein above for Example 3 (E3). The thickness of the wedge (x04) was adapted to change the distance (A1), and the non-magnetic matrix (x41) was adapted to suit the second device (x40) generating the magnetic field.

[00157] The OEL (x10) resulting from the magnetic assembly (x00) illustrated in FIG. 1-12 is shown in Fig. 3A-13A at various viewing angles with a substrate tilt (x20) from -30° to +30°, and a description of the optical impression of these OELs is described in Table 2.

[00158] The comparative OEL resulting from the magnetic assembly illustrated in FIG. 14-16 is shown in Fig. 15A-17A at various viewing angles with a substrate tilt from -30° to +30°, and a description of the optical impression of these OELs is described in Table 3.

Claims (37)

1. A method of obtaining on a substrate (x20) in the form of a protected document or a decorative element of a layer (x10) with an optical effect (OEL) providing an optical image of a crescent moving and rotating when said substrate is tilted, characterized in that said method includes the steps: i) applying to the surface of the substrate (x20) a radiation-curable coating composition containing non-spherical magnetic or magnetizable pigment particles, said radiation-curable coating composition being in a first state as a liquid state; ii) exposing the radiation-curable coating composition to a magnetic field by means of a magnetic assembly (x00) to orient at least a portion of the non-spherical magnetic or magnetizable pigment particles, said magnetic assembly (x00) comprising: a) a first magnetic field generating device (x30) whose north-south magnetic axis is perpendicular to the surface of the substrate (x20) and which has a length L1, b) a second magnetic field generating device (x40) whose north-south magnetic axis is perpendicular to the surface of the substrate (x20) and which has a length L3, c) a flat pole piece (x50) made without protrusions protruding outside the surface of said pole piece and having a length L5, wherein the first device (x30) generating a magnetic field and the second device (x40) generating a magnetic field have the same direction of the magnetic field, the first device (x30) that generates the magnetic field faces the substrate (x20) and is located on top of the pole piece (x50), the second device (x40) that generates the magnetic field is facing the environment and is located under the flat pole piece (x50), wherein the length L1 of the first device (x30) generating a magnetic field is less than the length L3 of the second device (x40) generating a magnetic field, the length L1 of the first device (x30) generating the magnetic field is less than the length L5 of the flat pole piece (x50), and the length L3 of the second device (x40) generating the magnetic field is less than the length L5 of the flat pole piece (x50), and iii) at least partially curing the radiation-curable coating composition after step ii) to form a second state of said composition, fixing the non-spherical magnetic or magnetizable pigment particles in their positions and orientations. 2. The method according to claim 1, characterized in that the magnetic assembly (x00) further comprises a non-magnetic plate (x60), preferably made of polyoxymethylene (POM), which is located between said first device (x30) and said second device (x40). 3. The method according to claim 1 or 2, characterized in that the magnetic assembly (x00) further comprises a second flat pole piece (x70) of length L9, said second pole piece being located under the second device (x40) generating a magnetic field, and addressed to the environment. 4. The method according to any one of paragraphs. 1–3, characterized in that the magnetic assembly (x00) additionally contains a magnetized plate (x80) containing one or more engravings and/or cutouts representing one or more characters, while said magnetized plate (x80) is preferably made of a composite material containing a polymer and a powder permanent magnet, and is located on top of the first device (x30), generating a magnetic field, and faces the substrate (x20). 5. The method according to any one of paragraphs. 1–4, characterized in that the flat pole piece (x50) is made of iron. 6. The method according to any one of paragraphs. 1-5, characterized in that the first device (x30), which generates a magnetic field, and the second device (x40), which generates a magnetic field, are disk-shaped devices that generate a magnetic field, and the values of their lengths L1 and L3 coincide with the values of their diameters , or said first device (x30) and second device (x40) are square-shaped magnetic field generating devices, and their lengths L1 and L3 are the same as their widths. 7. The method according to any one of paragraphs. 1-6, characterized in that non-spherical magnetic or magnetizable pigment particles are selected from the group consisting of magnetic thin-film interference pigment particles, magnetic cholesteric liquid crystal pigment particles and mixtures thereof. 8. The method according to any one of paragraphs. 1-7, characterized in that the non-spherical magnetic or magnetizable particles are lamellar pigment particles, and said method further comprises the step of exposing the radiation-curable coating composition to a dynamic magnetic field by means of a first magnetic field-generating device for biaxial orientation at least a portion of lamellar magnetic or magnetizable pigment particles, said step being carried out after step i) and before step ii). 9. Layer (x10) with an optical effect (OEL), which provides an optical image of a crescent moving and rotating when the substrate (x20) is tilted in the form of a protected document or decorative element containing the specified layer (x10), which is obtained by the method according to any one of paragraphs. 1–8. 10. An article representing a protected document or a decorative element, with at least one layer (x10), each of which is made with an optical effect (OEL), providing an optical image of a crescent moving and rotating when the substrate is tilted (x20) in the form of a protected document or decorative element containing the specified layer (x10), in which each of the specified at least one layer is a layer according to claim 9. 11. Magnetic assembly (x00) to obtain a layer (x10) with an optical effect (OEL), providing an optical image of a crescent moving and rotating when the substrate (x20) is tilted in the form of a protected document or decorative element containing the specified layer (x10), moreover said layer (x10) contains oriented non-spherical magnetic or magnetizable pigment particles in a radiation cured coating composition, characterized in that said magnetic assembly (x00) comprises: a) a first magnetic field generating device (x30) whose north-south magnetic axis is perpendicular to the surface of the substrate (x20) and which has a length L1, b) a second magnetic field generating device (x40) whose north-south magnetic axis is perpendicular to the surface of the substrate (x20) and which has a length L3, c) a flat pole piece (x50) made without protrusions protruding outside the surface of said pole piece and having a length L5, wherein the first device (x30) generating a magnetic field and the second device (x40) generating a magnetic field have the same direction of the magnetic field, the first device (x30) that generates the magnetic field faces the substrate (x20) and is located on top of the pole piece (x50), the second device (x40) that generates the magnetic field is facing the environment and is located under the pole piece (x50), wherein the length L1 of the first device (x30) generating a magnetic field is less than the length L3 of the second device (x40) generating a magnetic field, the length L1 of the first magnetic field generating device (x30) is less than the length L5 of the pole piece (x50), and the length L3 of the second device (x40) generating the magnetic field is less than the length L5 of the pole piece (x50). 12. Magnetic assembly (x00) according to claim 11, characterized in that the assembly further comprises a non-magnetic plate (x60), which is located between said first device (x30) and said second device (x40), and/or additionally contains a second flat pole piece (x70) with a length L9, while the specified second pole piece is located under the second device (x40) that generates a magnetic field and faces the environment, and the length L1 of the first device (x30) that generates a magnetic field less than the length L9 of said second pole piece (x70), and the length L3 of the second magnetic field generating device (x40) is less than the length L9 of said second pole piece (x70), and/or additionally contains a magnetized plate (x80) containing one or more engravings and/or cutouts representing one or more characters, while the specified magnetized plate (x80) is preferably made of a composite material containing a polymer and a powder permanent magnet, and at the same time magnetized the plate (x80) is located on top of the first magnetic field generating device (x30) and faces the substrate (x20). 13. Magnetic assembly according to claim 11 or 12, characterized in that it is located in a holder (x01) mounted on a transfer device, preferably a rotating magnetic cylinder. 14. Printing device for obtaining on a substrate (x20) a layer (x10) with an optical effect (OEL), providing an optical image of a crescent moving and rotating when the substrate (x20) is tilted in the form of a protected document or a decorative element containing the specified layer (x10) , which contains a rotating magnetic cylinder containing at least one of the magnetic assemblies (x00) according to any one of paragraphs. 11-13, or flatbed printing unit containing at least one of the magnetic assemblies (x30) according to any one of paragraphs. 11–13.

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