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WO2025233239A1 - Procédés de production de couches à effet optique - Google Patents

Procédés de production de couches à effet optique

Info

Publication number
WO2025233239A1
WO2025233239A1 PCT/EP2025/062055 EP2025062055W WO2025233239A1 WO 2025233239 A1 WO2025233239 A1 WO 2025233239A1 EP 2025062055 W EP2025062055 W EP 2025062055W WO 2025233239 A1 WO2025233239 A1 WO 2025233239A1
Authority
WO
WIPO (PCT)
Prior art keywords
magnetic
motif
pigment particles
platelet
substrate
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
PCT/EP2025/062055
Other languages
English (en)
Inventor
Nathalie Benninger
Gisèle BAUDIN
Cédric Amerasinghe
Aude PUJOL
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
SICPA Holding SA
Original Assignee
SICPA Holding SA
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by SICPA Holding SA filed Critical SICPA Holding SA
Publication of WO2025233239A1 publication Critical patent/WO2025233239A1/fr
Pending legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05D3/00—Pretreatment of surfaces to which liquids or other fluent materials are to be applied; After-treatment of applied coatings, e.g. intermediate treating of an applied coating preparatory to subsequent applications of liquids or other fluent materials
    • B05D3/20—Pretreatment of surfaces to which liquids or other fluent materials are to be applied; After-treatment of applied coatings, e.g. intermediate treating of an applied coating preparatory to subsequent applications of liquids or other fluent materials by magnetic fields
    • B05D3/207—Pretreatment of surfaces to which liquids or other fluent materials are to be applied; After-treatment of applied coatings, e.g. intermediate treating of an applied coating preparatory to subsequent applications of liquids or other fluent materials by magnetic fields post-treatment by magnetic fields
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05D5/00—Processes for applying liquids or other fluent materials to surfaces to obtain special surface effects, finishes or structures
    • B05D5/06—Processes for applying liquids or other fluent materials to surfaces to obtain special surface effects, finishes or structures to obtain multicolour or other optical effects
    • B05D5/065—Processes for applying liquids or other fluent materials to surfaces to obtain special surface effects, finishes or structures to obtain multicolour or other optical effects having colour interferences or colour shifts or opalescent looking, flip-flop, two tones
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05D3/00—Pretreatment of surfaces to which liquids or other fluent materials are to be applied; After-treatment of applied coatings, e.g. intermediate treating of an applied coating preparatory to subsequent applications of liquids or other fluent materials
    • B05D3/06—Pretreatment of surfaces to which liquids or other fluent materials are to be applied; After-treatment of applied coatings, e.g. intermediate treating of an applied coating preparatory to subsequent applications of liquids or other fluent materials by exposure to radiation
    • B05D3/061—Pretreatment of surfaces to which liquids or other fluent materials are to be applied; After-treatment of applied coatings, e.g. intermediate treating of an applied coating preparatory to subsequent applications of liquids or other fluent materials by exposure to radiation using U.V.
    • B05D3/065—After-treatment
    • B05D3/067—Curing or cross-linking the coating

Definitions

  • the invention relates to the field of security printing processes, as well as security features produced using such security printing processes.
  • the invention relates to optical effect layers (OELs), and the use of such OELs as anticounterfeit features on security documents or security articles, as well as for decorative purposes.
  • OELs optical effect layers
  • inks, compositions, coatings or layers containing oriented magnetic or magnetizable pigment particles, particularly also optically variable magnetic or magnetizable pigment particles for the production of security elements, e.g. in the field of security documents.
  • Coatings or layers comprising oriented magnetic or magnetizable pigment particles are disclosed for example in US2,570,856; US3,676,273; US3,791 ,864; US5,630,877; and US5, 364,689.
  • Coatings or layers comprising oriented magnetic color-shifting pigment particles, resulting in particularly appealing optical effects, useful for the protection of security documents, have been disclosed in W02002/090002A2 and W02005/002866A1 .
  • Security features e.g. for security documents
  • the protection provided by covert security features relies on the principle that such features are difficult to detect, typically requiring specialized equipment and knowledge for detection, whereas “overt” security features rely on the concept of being easily detectable with the unaided human senses, e.g. such features may be visible and/or detectable via the tactile sense while still being difficult to produce and/or to copy.
  • covert security features rely on the concept of being easily detectable with the unaided human senses, e.g. such features may be visible and/or detectable via the tactile sense while still being difficult to produce and/or to copy.
  • the effectiveness of overt security features depends to a great extent on their easy recognition as a security feature.
  • Magnetic or magnetizable pigment particles in printing inks or coatings allow for the production of magnetically induced images, designs and/or patterns, which are referred to in the art as “Optical Effect Layers” (OELs), through the application of a correspondingly structured magnetic field, inducing a local orientation of the magnetic or magnetizable pigment particles in the not yet hardened (i.e. wet) coating, followed by the hardening of the coating.
  • OELs Optical Effect Layers
  • Materials and technologies for the orientation of magnetic or magnetizable pigment particles in coating compositions are known.
  • the magnetically induced images in question can only be produced by having access to both, the magnetic or magnetizable pigment particles or the corresponding ink, and the particular technology employed to print said ink and to orient said pigment in the printed ink.
  • OELs are obtained by using specific magnetic assemblies and advantageously exhibit a dynamic appearance upon tilting.
  • dynamic OELs include reflection zone bars moving as the OEL is tilted, loop-shaped bodies moving as the OEL is tilted, loop-shaped bodies having a varying shape as the OEL is tilted, bright areas and dark areas moving as the OEL is tilted.
  • W02012/104098A1 discloses OELs comprising more than one magnetically induced images, each image having a different magnetic orientation pattern.
  • W02012/104098A1 discloses an OEL comprising two areas, each one exhibiting a reflection zone bar moving as the OEL is tilted, one of said bar moving away the observer upon tilting of the OEL and the other said bar moving towards the observer upon tilting of the OEL.
  • Processes for producing OELs comprising at least two areas made of a single cured layer, comprises i) applying on the substrate a UV curable ink comprising magnetic or magnetizable particles to form a coating layer; ii) exposing the coating layer to the magnetic field of a magnetic-field-generating device, thereby orienting the pigment particles, iii) curing one or more first areas of the coating layer to a second state to fix the magnetic or magnetizable particles in their adopted positions and orientations, said curing being performed by selectively irradiating the coating layer with a radiation source; iv) exposing the coating layer to the magnetic field of a magnetic-field-generating device thereby reorienting the magnetic or magnetizable particles which are comprised in the coating layer still being in a wet, liquid state and not yet-cured due to the selective curing of step iii) and v) curing the coating layer to fix the magnetic or magnetizable particles in their new adopted positions and orientations.
  • a fixed photomask may be used with a coating layer being carried by a moving substrate. Said method may also result in the production of shadow effects on the coating layer and/or image blurring due to a substrate movement at industrial speeds during exposition to irradiation, without any possibility to implement a variable image information during printing.
  • a moving photomask may be used with a moving substrate. However, said method may also result in the production of shadow effects on the coating layer resulting in a low- resolution imaging and would be highly complex to implement.
  • Another method uses laser beams.
  • said method is known to require highly special equipment and high costs.
  • LED Light Emitting Diode
  • Another method uses LED Light Emitting Diode (LED) arrays.
  • LED Light Emitting Diode
  • this method may suffer from unnecessary losses of light density resulting in longer curing times and degrading the printing performance.
  • a need remains for improved and controlled processes for producing eye-catching OELs for security printers at industrial speed, wherein said so-produced OELs are easily authenticated by the person in the street while said processes are highly difficult to be implemented on a mass-scale production by counterfeiters and the illicit market.
  • the invention provides a process for producing an optical effect layer (OEL) on a substrate (220), said OEL comprising a first motif comprising platelet-shaped magnetic or magnetizable pigment particles oriented according to a first magnetic pattern and a second motif comprising platelet-shaped magnetic or magnetizable pigment particles oriented according to a second magnetic pattern, wherein one or both of the first and second motifs further comprises a luminescent pigment or dye, which first and second motifs together form a composite motif, said process comprising: a) applying onto the substrate (220) a first radiation-curable coating composition, preferably a first UV-Vis-curable coating composition, exhibiting a coIor and comprising the platelet-shaped magnetic or magnetizable pigment particles to form a first coating layer (210) on said substrate (220), said coating composition being in a first state; b) exposing the first radiation-curable coating composition of step a) to a magnetic field of a magnetic assembly (230) to magnetically orient at
  • the invention provides an OEL comprising:
  • a first motif composed of a first coating layer comprising platelet-shaped magnetic or magnetizable pigment particles suspended in a polymerized vehicle, wherein the platelet-shaped magnetic or magnetizable pigment particles are permanently oriented according to a first predetermined orientation
  • a second motif in register with the first motif, composed of a second coating layer comprising platelet- shaped magnetic or magnetizable pigment particles suspended in a polymerized vehicle, wherein the platelet-shaped magnetic or magnetizable pigment particles are permanently oriented according to a second predetermined orientation
  • the first motif and the second motif together form a composite motif, and wherein one or both of the first and second coating layers further comprises at least one luminescent pigment or dye.
  • the invention provides an OEL obtainable by or obtained by the process of the invention.
  • Fig. 1 depicts schematically a platelet-shaped pigment particle.
  • Fig. 2 depict schematically an embodiment of the process of the invention.
  • Fig. 3 depict schematically an embodiment of the process of the invention.
  • Fig. 4 depicts schematically an embodiment of the process of the invention.
  • Figs. 5a-5c schematically illustrate the screens used to prepare the examples E1-E3 shown in Fig. 12.
  • Fig. 5a a) depicts the screen used for the first coating layer of Example E1
  • Fig. 5a b) depicts the screen used for the second coating layer of Example E1
  • Fig. 5b a) depicts the screen used for the first coating layer of Example E2
  • Fig. 5b b) depicts the screen used for the second coating layer of Example E2
  • Fig. 5c a) depicts the screen used for the first coating layer of Example E3
  • Fig. 5c b) depicts the screen used for the second coating layer of Example E3.
  • Fig. 6 depicts schematically a first coating layer (210) and a second coating layer (210’), which printed in register together yield a composite motif (OEL).
  • OEL composite motif
  • Fig. 7 depicts schematically a first coating layer (210) and a second coating layer (210’), which printed in register together yield a composite motif (OEL).
  • OEL composite motif
  • Figs. 8A-B schematically illustrate methods for producing an OEL on a substrate (220) on an industrial printing press according to the invention.
  • the curved arrows denote the direction of rotation of the cylinders (A) and (B).
  • a coating layer (210) comprising platelet-shaped pigment particles is applied on a substrate (220) by screen-printing using a raster screen (290), the substrate (220) moves in the vicinity of a first magnetic-field-generating device (230), the substrate (220) is then transferred on a first rotating magnetic cylinder (A) carrying several first magnetic-field-generating devices (240) (Fig.
  • the coating layer (210) is then at least partially cured with a first curing unit (250), a second coating layer (210’) is applied in register on the substrate (220) by screen-printing using a raster screen (290’), the substrate (220) moves in the vicinity of a second static magnetic-field-generating device (230’), the substrate (220) is then transferred on a second rotating magnetic cylinder carrying several second magnetic-field- generating devices (240’) (Fig. 8A) and rotating in the vicinity of a static magnetic field generating device (230’) (Fig. 8B), and the coating layer is then at least partially cured using a second curing unit (250’).
  • One or both of coating layers (210) and (210’) comprise at least one luminescent pigment or dye.
  • Fig. 9 schematically illustrates a top view of a static magnetic-field-generating device (230 or 230’) as used in the steps b1) and/or b’1) and/or b2) and/or b’2) of the method of the invention.
  • Fig. 10 schematically illustrates an example of a magnetic-field-generating device (240) as used for examples E1-E3 in the steps b2) and b’2) of the method of the invention.
  • Fig. 11 shows the tilting of the substrate in the Examples to observe the angle-dependent color shifts.
  • Fig. 12 shows the OELs of Examples E1-E3, when illuminated with ambient light (no particular angle of incidence) and observed at the tilt angles of -45°, 0° and +45°, as shown in Fig. 11 , and when illuminated with UV light (365 nm) (last column).
  • the term “about” means that the amount or value in question may be the value designated or some other value about the same.
  • the phrases are intended to convey that similar values within a range of ⁇ 5% of the indicated value promote equivalent results or effects according to the invention.
  • UV ultraviolet
  • UV ultraviolet
  • UV-VIS as used herein is intended to mean irradiation having a wavelength component in the ultraviolet and/or visible part of the electromagnetic spectrum; typically from 200 nm to 800 nm.
  • the term “at least one” is meant to define one or more than one, for example one or two or three.
  • the term “and/or” means that either all or only one of the elements of said group may be present.
  • a and/or B shall mean “only A, or only B, or both A and B”. In the case of “only A”, the term also covers the possibility that B is absent, i.e. “only A, but not B”.
  • a coating composition comprising a compound A may include other compounds besides A.
  • the term “comprising” also covers, as a particular embodiment thereof, the more restrictive meanings of “consisting essentially of’ and “consisting of’, so that for instance “a fountain solution comprising A, B and optionally C” may also (essentially) consist of A and B, or (essentially) consist of A, B and C.
  • acrylate encompasses molecules bearing acrylate and/or (meth)acrylate moieties.
  • optical effect layer denotes a coating or layer that comprises oriented platelet-shaped magnetic or magnetizable pigment particles and a binder, wherein said platelet-shaped magnetic or magnetizable pigment particles are oriented by a magnetic field and wherein the oriented platelet-shaped magnetic or magnetizable pigment particles are fixed/frozen in their orientation and position (i.e. after hardening/curing) to form a magnetically induced image.
  • coating composition refers to any composition which is capable of forming an OEL on a solid substrate and which can be applied preferably but not exclusively by a printing method.
  • the coating composition comprises the platelet-shaped magnetic or magnetizable pigment particles and the binder, and optionally at least one luminescent pigment or dye.
  • security document refers to a document which is usually protected against counterfeit or fraud by at least one security feature.
  • security documents include without limitation value documents and value commercial goods.
  • security feature is used to denote an image, pattern or graphic element that can be used for authentication purposes.
  • the term “luminescent” means emitting electromagnetic radiation at one wavelength upon irradiation with electromagnetic radiation of a different wavelength.
  • the inventors have created novel OELs using a process in which a first radiation-curable coating composition, preferably a first UV-Vis-curable coating composition, comprising platelet-shaped magnetic or magnetizable pigment particles is applied, preferably printed, in register with a second radiation-curable coating composition, preferably a second UV-Vis-curable coating composition, comprising platelet-shaped magnetic or magnetizable pigment particles, and in which one or both of the first and second coating compositions comprises at least one luminescent pigment or dye, to create visually appealing composite motifs, which can be readily evaluated by the naked eye to authenticate documents or articles bearing the OELs, and which emit radiation by luminescence when illuminated with UV light.
  • a first radiation-curable coating composition preferably a first UV-Vis-curable coating composition, comprising platelet-shaped magnetic or magnetizable pigment particles
  • a second radiation-curable coating composition preferably a second UV-Vis-curable coating composition, comprising platelet-shaped magnetic or magnetizable pigment particles
  • the invention provides processes for producing OELs that are suitable as security features against counterfeit or fraud and which comprise magnetically oriented platelet-shaped magnetic or magnetizable pigment particles on a substrate.
  • the OELs comprise a first motif (in the form of a cured first coating layer 210) comprising platelet-shaped magnetic or magnetizable pigment particles oriented according to a first magnetic pattern and a second motif (in the form of a cured second coating layer 210’) comprising platelet-shaped magnetic or magnetizable pigment particles oriented according to a second magnetic pattern, wherein one or both of the first and second coating layers comprises at least one luminescent pigment or dye, wherein said second motif is applied in register with said first motif.
  • register as used herein is defined as follows:
  • “Register” means that when two or more component motifs of a Designed Motif are applied and together form a composite motif, the composite motif reproduces the Designed Motif with a deviation of less than 1 mm, preferably less than 0.5 mm, more preferably less than or equal to 0.2 mm.
  • Designed Motif means a motif as designed, which motif can be broken down into component motifs.
  • the process of the invention comprises at least two sets of steps, i.e. a first set comprising steps a), b) and c) in which a first motif is created comprising platelet-shaped magnetic or magnetizable pigment particles oriented according to a first magnetic pattern, and at least a second set comprising steps a’), b’) and c’), in which a second motif is created comprising platelet-shaped magnetic or magnetizable pigment particles oriented according to a second magnetic pattern, and wherein one or both of the first and second motifs comprises at least one luminescent pigment or dye.
  • the first motif and the second motif are printed in register, and may be adjacent and touching, intercalated, adjacent and spaced apart, or overlapping. The overlap may be zero, partial or total, preferably zero or partial, more preferably zero.
  • the first magnetic pattern and the second magnetic pattern may be the same or different.
  • the process of the invention is preferably a continuous process meaning that steps a’), b’) and c’) are carried out directly after steps a), b) and c), and the substrate (220) carrying the first coating layer (210) is not removed from the printing machine, i.e. is continuously fed, to carry out the following steps, using a single machine, said machine allowing the application, preferably printing, of coating compositions, the exposure of said compositions to magnetic fields and the at least partial curing of said compositions, said process allowing the preparation of OELs comprising the first motif and the second motif (optionally additional motifs) wherein the first and second (and any other component motifs) are in register.
  • the process of the invention comprises steps a), b) and c) in which a first motif is created comprising platelet-shaped magnetic or magnetizable pigment particles oriented according to a first magnetic pattern, steps a’), b’) and c’) in which a second motif is created in register comprising platelet-shaped magnetic or magnetizable pigment particles oriented according to a second magnetic pattern, and steps a”), b”) and c”), in which a third motif is created in register comprising platelet-shaped magnetic or magnetizable pigment particles oriented according to a third magnetic pattern, wherein at least one of the first, second and third motifs comprises a luminescent pigment or dye.
  • references to features and preferred features of steps a), b), and c), are understood to apply equally and independently to steps a’), b’), and c’), steps a”), b”), and c”), and so on.
  • step c) is carried out partially simultaneously with, step b;
  • step b’2) the second coating layer (210’) is optionally exposed to a fourth magnetic assembly (240’) to re-orient the particles in a design-specific manner;
  • the curing is carried out without removing the substrate (220) from the influence of the third (230’) or fourth (240’) magnetic assembly, i.e. step c’) is carried out partially simultaneously with, step b’).
  • One or both of the first and second coating layers comprises at least one luminescent pigment or dye.
  • step c) is carried out partially simultaneously with, step b;
  • the curing is carried out without removing the substrate (220) from the influence of the third (230’) or fourth (240’) magnetic assembly, i.e. step c’) is carried out partially simultaneously with, step b’).
  • the first and second motifs are at least partially intercalated.
  • One or both of the first and second coating layers comprises at least one luminescent pigment or dye.
  • the first and second coating layers are applied to the same side of the substrate.
  • the substrate is at least partially transparent and the first and second coating layers are applied in register to opposite sides of the substrate.
  • Fig. 4 depicts an embodiment of the process of the invention in which the first (210) and second (210’) coating layers are applied to opposite sides of the substrate (220), and the substrate (220) is at least partially transparent: step a): a screen (290) having the first motif is used to print the first radiation-curable coating composition comprising platelet-shaped magnetic or magnetizable pigment particles onto the substrate (220), to form the first coating layer (210); step b1): the first coating layer (210) is exposed to a first magnetic assembly (230) to bi-axially orient the pigment particles; step b2): the first coating layer (210) is optionally exposed to a second magnetic assembly (240) to reorient the particles in a design-specific manner; step c): the first coating layer (210) having specifically oriented pigment particles is cured by exposure to radiation of a curing unit (250) to form the first motif.
  • step a) a screen (290) having the first motif is used to print the first radiation-curable coating composition comprising platelet-shaped magnetic or magnet
  • step c) is carried out partially simultaneously with, step b;
  • the curing is carried out without removing the substrate (220) from the influence of the third (230’) or fourth (240’) magnetic assembly, i.e. step c’) is carried out partially simultaneously with, step b’).
  • the first and second motifs are on opposite sides of the substrate. Because the substrate is partially transparent, the first and second motifs together form a composite motif.
  • One or both of the first and second coating layers comprises at least one luminescent pigment or dye.
  • the first (210) and second (210’) coating layers comprising platelet-shaped magnetic or magnetizable particles can differ in several ways, for example:
  • they may comprise different platelet-shaped magnetic or magnetizable pigment particles
  • the magnetic orientations in the two coating layers may be different
  • one of the coating layers may comprise a luminescent pigment or dye, and the other may not;
  • FIGs. 8A and 8B schematically illustrate a method for producing an OEL on a substrate (220) on an industrial printing press according to the invention.
  • the curved arrows denote the direction of rotation of the cylinders (A) and (B).
  • a coating layer (210) comprising platelet-shaped pigment particles is applied on a substrate (220) by screen-printing using a raster screen (290), the substrate (220) moves in the vicinity of a first magnetic-field-generating device (230), the substrate (220) is then transferred on a first rotating magnetic cylinder (A) carrying several second magnetic-field-generating devices (240) and optionally rotating in the vicinity of a static magnetic field generating device (230) (Fig.
  • the coating layer (210) is then at least partially cured with a first curing unit (250), a second coating layer (210’) is applied in register on the substrate (220) by screen-printing using a raster screen (290’), the substrate (220) moves in the vicinity and on top of a third static magnetic-field-generating device (230’), the substrate (220) is then transferred on a second rotating magnetic cylinder carrying several fourth magnetic-field-generating devices (240’) and optionally rotating in the vicinity of a static magnetic field generating device (230’) (Fig. 8B), and the coating layer is then at least partially cured using a second curing unit (250’).
  • One or both of coating layers (210) and (210’) comprise at least one luminescent pigment or dye.
  • steps a) and a’) are independently carried out by a printing process, preferably independently selected from the group consisting of screen-printing, rotogravure printing, flexography printing and intaglio printing (also referred to in the art as engraved copper plate printing and engraved steel die printing), more preferably selected from the group consisting of screen-printing, rotogravure printing and flexography printing and still more preferably by screen-printing.
  • a printing process preferably independently selected from the group consisting of screen-printing, rotogravure printing, flexography printing and intaglio printing (also referred to in the art as engraved copper plate printing and engraved steel die printing), more preferably selected from the group consisting of screen-printing, rotogravure printing and flexography printing and still more preferably by screen-printing.
  • Screen-printing is a stencil process wherein an ink is transferred to a surface through a stencil supported by a fine fabric mesh of silk, mono- or multi-filaments made of synthetic fibers such as for example polyamides or polyesters or metal threads stretched tightly on a frame made for example of wood or metal (e.g. aluminum or stainless steel).
  • the screen-printing mesh may be a chemically etched, a laser-etched, or a galvanically formed porous metal foil, e.g. a stainless-steel foil. The pores of the mesh are blocked in the non-image areas and left open in the image area, the image carrier being called the screen.
  • Screen-printing might be of the flat-bed or rotary type. Screen-printing is further described for example in The Printing ink manual, R.H. Leach and R.J. Pierce, Springer Edition, 5th Edition, pages 58-62 and in Printing Technology, J.M. Adams and P.A. Dolin, Delmar Thomson Learning, 5th Edition, pages 293-328.
  • Rotogravure also referred to in the art as gravure is a printing process wherein the image elements are engraved into the surface of a cylinder. The non-image areas are at a constant original level. Prior to printing, the entire printing plate (non-printing and printing elements) is inked and flooded with ink. Ink is removed from the non-image by a wiper or a blade before printing, so that ink remains only in the cells. The image is transferred from the cells to the substrate by a pressure typically in the range of 2 to 4 bars and by the adhesive forces between the substrate and the ink.
  • rotogravure does not encompass intaglio printing processes (also referred to in the art as engraved steel die or copper plate printing processes) which rely for example on a different type of ink. More details are provided in “Handbook of print media”, Helmut Kipphan, Springer Edition, page 48 and in The Printing ink manual, R.H. Leach and R.J. Pierce, Springer Edition, 5th Edition, pages 42-51.
  • Flexography preferably uses a unit with a doctor blade, preferably a chambered doctor blade, an anilox roller and plate cylinder.
  • the anilox roller advantageously has small cells whose volume and/or density determines the ink application rate.
  • the doctor blade lies against the anilox roller, and scrapes off surplus ink at the same time.
  • the anilox roller transfers the ink to the plate cylinder which finally transfers the ink to the substrate.
  • Specific design might be achieved using a designed photopolymer plate.
  • Plate cylinders can be made from polymeric or elastomeric materials. Polymers are mainly used as photopolymer in plates and sometimes as a seamless coating on a sleeve.
  • Photopolymer plates are made from light-sensitive polymers that are hardened by ultraviolet (UV) light. Photopolymer plates are cut to the required size and placed in an UV light exposure unit. One side of the plate is completely exposed to UV light to harden or cure the base of the plate. The plate is then turned over, a negative of the job is mounted over the uncured side and the plate is further exposed to UV light. This hardens the plate in the image areas. The plate is then processed to remove the unhardened photopolymer from the nonimage areas, which lowers the plate surface in these nonimage areas. After processing, the plate is dried and given a post-exposure dose of UV light to cure the whole plate. Preparation of plate cylinders for flexography is described in Printing Technology, J. M. Adams and P.A. Dolin, Delmar Thomson Learning, 5th Edition, pages 359-360 and in The Printing ink manual, R.H. Leach and R.J. Pierce, Springer Edition, 5th Edition, pages 33-42.
  • the first and second radiation-curable coating compositions as well as the first and second coating layers comprise platelet-shaped magnetic or magnetizable pigment particles.
  • plateletshaped pigment particles are quasi two-dimensional particles due to the large aspect ratio of their dimensions.
  • platelet-shaped pigment particle can be considered as having a two- dimensional structure wherein the dimensions X and Y are substantially larger than the dimension Z.
  • Platelet-shaped pigment particles are also referred to in the art as oblate particles or flakes.
  • Such pigment particles may be described with a main axis X corresponding to their longest dimension crossing the pigment particle and a second axis Y perpendicular to X and corresponding to the second longest dimension crossing the pigment particle.
  • the XY plane roughly defines the plane formed by the first and second longest dimensions of the pigment particle, the Z dimension being ignored.
  • the first and second radiation-curable coating compositions are independently applied during steps a) and a’) thus forming the first coating layer (210) and the second coating layer (210’), respectively.
  • the first and second radiation-curable coating compositions preferably independently comprise a binder and the platelet-shaped magnetic or magnetizable pigment particles, and at least one or both of the coating layers comprises at least one luminescent pigment or dye.
  • the platelet-shaped magnetic or magnetizable pigment particles have, due to their platelet shape, non-isotropic reflectivity with respect to incident electromagnetic radiation for which the hardened/cured binder material is at least partially transparent.
  • non-isotropic reflectivity denotes that the proportion of incident radiation from a first angle that is reflected by a particle into a certain (viewing) direction (a second angle) is a function of the orientation of the particles, i.e. that a change of the orientation of the particle with respect to the first angle can lead to a different magnitude of the reflection to the viewing direction.
  • the platelet-shaped magnetic or magnetizable pigment particles are dispersed in the first coating layer (210) and the second coating layer (210’), respectively.
  • the first and second coating layers comprise, independently, a hardened binder material that fixes the orientation of the platelet-shaped magnetic or magnetizable pigment particles.
  • the binder material is at least in its hardened or solid state (also referred to as second state herein), and is at least partially transparent to electromagnetic radiation of a range of wavelengths comprised between 200 nm and 2,500 nm, i.e. within the wavelength range which is typically referred to as the “optical spectrum” and which comprises infrared, visible and UV portions of the electromagnetic spectrum.
  • the particles contained in the binder material in its hardened or solid state and their orientation-dependent reflectivity can be perceived through the binder material at some wavelengths within this range.
  • the hardened binder material is at least partially transparent to electromagnetic radiation of a range of wavelengths comprised between 200 nm and 800 nm, more preferably comprised between 400 nm and 700 nm.
  • the term “transparent” denotes that the transmission of electromagnetic radiation through a layer of 20 pm of the hardened binder material as present in the OEL (not including the platelet-shaped magnetic or magnetizable pigment particles, but all other optional components of the OEL in case such components are present) is at least 50%, more preferably at least 60 %, even more preferably at least 70%, at the wavelength(s) concerned. This can be determined for example by measuring the transmittance of a test piece of the hardened binder material (not including the platelet-shaped magnetic or magnetizable pigment particles) in accordance with well-established test methods, e.g. DIN 5036-3 (1979-11).
  • the platelet-shaped magnetic or magnetizable pigment particles are defined as having, due to their platelet shape, non-isotropic reflectivity with respect to an incident electromagnetic radiation for which the cured binder material is at least partially transparent.
  • non-isotropic reflectivity denotes that the proportion of incident radiation from a first angle that is reflected by a particle into a certain (viewing) direction (a second angle) is a function of the orientation of the particles, i.e. that a change of the orientation of the particle with respect to the first angle can lead to a different magnitude of the reflection to the viewing direction.
  • the platelet-shaped magnetic or magnetizable pigment particles have a non-isotropic reflectivity with respect to incident electromagnetic radiation in some parts or in the complete wavelength range of from about 200 to about 2500 nm, more preferably from about 400 to about 700 nm, such that a change of the particle’s orientation results in a change of reflection by that particle into a certain direction.
  • the magnetic or magnetizable pigment particles are different from conventional pigments and different from color-constant dyes and color-constant pigments, in that said conventional pigment particles exhibit the same color and reflectivity, independent of the particle orientation, whereas the magnetic or magnetizable pigment particles exhibit either a reflection or a color, or both, that depend on the particle orientation.
  • the first and second radiation-curable coating compositions as well as the first and second coating layers comprise, independently, the platelet-shaped magnetic or magnetizable pigment particles preferably in an amount from about 1 wt.% and about 40 wt.%, preferably between about 3 wt.% and about 35 wt.%, more preferably between about 5 wt.% and about 30 wt.%, the weight percentages being based on the total weight of the respective radiation-curable coating composition or the respective coating layer.
  • Suitable examples of platelet-shaped magnetic or magnetizable pigment particles include without limitation pigment particles comprising a magnetic metal selected from the group consisting of cobalt (Co), iron (Fe), and nickel (Ni); a magnetic alloy of iron, manganese, cobalt, nickel or a mixture of two or more thereof; a magnetic oxide of chromium, manganese, cobalt, iron, nickel or a mixture of two or more thereof; or a mixture of two or more thereof.
  • the term “magnetic” in reference to the metals, alloys and oxides is directed to ferromagnetic or ferrimagnetic metals, alloys and oxides.
  • Magnetic oxides of chromium, manganese, cobalt, iron, nickel or a mixture of two or more thereof may be pure or mixed oxides.
  • magnetic oxides include without limitation iron oxides such as hematite (Fe2Os), magnetite (FesC ), chromium dioxide (CrC>2), magnetic ferrites (MFe2C>4), magnetic spinels (MR2O4), magnetic hexaferrites (MFei2Oi9), magnetic orthoferrites (RFeCh), magnetic garnets MSR2(AO4)3, wherein M stands for two-valent metal, R stands for three-valent metal, and A stands for four-valent metal.
  • Examples of platelet-shaped magnetic or magnetizable pigment particles include without limitation pigment particles comprising a magnetic layer M made from one or more of a magnetic metal such as cobalt (Co), iron (Fe), or nickel (Ni); and a magnetic alloy of iron, cobalt or nickel, wherein said magnetic or magnetizable pigment particles may be multilayered structures comprising one or more additional layers.
  • a magnetic metal such as cobalt (Co), iron (Fe), or nickel (Ni)
  • a magnetic alloy of iron, cobalt or nickel wherein said magnetic or magnetizable pigment particles may be multilayered structures comprising one or more additional layers.
  • the one or more additional layers are layers A independently made from one or more selected from the group consisting of metal fluorides such as magnesium fluoride (MgF2), silicon oxide (SiO), silicon dioxide (SiC>2), titanium oxide (TiC>2), and aluminum oxide (AI2O3), more preferably silicon dioxide (SiC>2); or layers B independently made from one or more 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 silver (Ag), aluminum (Al), chromium (Cr), and nickel (Ni), and still more preferably aluminum (Al); or a combination of one or more layers A such as those described hereabove and one or more layers B such as those described hereabove.
  • metal fluorides such as magnesium fluoride (MgF2), silicon oxide (SiO), silicon dioxide (SiC>2), titanium oxide (TiC>2), and aluminum oxide (AI2O3), more
  • Typical examples of the platelet-shaped magnetic or magnetizable pigment particles being multilayered structures described hereabove include without limitation A/M multilayer structures, A/M/A multilayer structures, A/M/B multilayer structures, A/B/M/A multilayer structures, A/B/M/B multilayer structures, A/B/M/B/A/multilayer structures, B/M multilayer structures, B/M/B multilayer structures, M/A/M multilayer structures, B/A/M/A multilayer structures, B/A/M/B multilayer structures, B/A/M/B/A multilayer structures, B/A/M/A/B multilayer structures, B/A/B/A/M/A/B/A/B multilayer structures, A/B/A/B/A/M/A/B/A/B/A multilayer structures, wherein the layers A, the magnetic layers M and the layers B are chosen from those described hereabove.
  • the radiation-curable coating composition may comprise platelet-shaped optically variable magnetic or magnetizable pigment particles, and/or platelet-shaped magnetic or magnetizable pigment particles having no optically variable properties.
  • the platelet-shaped magnetic or magnetizable pigment particles is constituted by platelet-shaped optically variable magnetic or magnetizable pigment particles.
  • the optical properties of the optically variable magnetic or magnetizable pigment particles may also be used as a machine readable tool for the recognition of the OEL.
  • the optical properties of the optically variable magnetic or magnetizable pigment particles may simultaneously be used as a covert or semi-covert security feature in an authentication process wherein the optical (e.g. spectral) properties of the pigment particles are analyzed and thus increase the counterfeiting resistance.
  • platelet-shaped optically variable magnetic or magnetizable pigment particles in coating layers for producing an OEL enhances the significance of the OEL as a security feature in security document applications, because such materials are reserved to the security document printing industry and are not commercially available to the public.
  • the platelet-shaped magnetic or magnetizable pigment particles is constituted by platelet-shaped optically variable magnetic or magnetizable pigment particles. These are more preferably selected from the group consisting of platelet-shaped magnetic thin-film interference pigment particles, platelet-shaped interference coated pigment particles.
  • Magnetic thin film interference pigment particles are known to those skilled in the art and are disclosed e.g. in US4,838,648; W02002/073250A2; EP0686675B1 ; W02003/000801A2; US6,838,166; WO2007/131833A1 ; EP2402401 B1 ; WO2019/103937A1 ; EP3587500A1 ,
  • the magnetic thin film interference pigment particles comprise pigment particles having a five-layer Fabry-Perot multilayer structure and/or pigment particles having a six-layer Fabry-Perot multilayer structure and/or pigment particles having a seven-layer Fabry-Perot multilayer structure and/or pigment particles having a nine-layer Fabry-Perot multilayer structure and/or pigment particles having an elevenlayer Fabry-Perot multilayer structure and/or pigment particles having a multilayer structure combining one or more multilayer Fabry-Perot structures.
  • Preferred five-layer Fabry-Perot multilayer structures consist of absorber/dielectric/reflector/dielectric/absorber multilayer structures wherein the reflector and/or the absorber is also a magnetic layer, preferably the reflector and/or the absorber is a magnetic layer comprising nickel, iron and/or cobalt, and/or a magnetic alloy comprising nickel, iron and/or cobalt and/or a magnetic oxide comprising nickel (Ni), iron (Fe) and/or cobalt (Co).
  • Further preferred five-layer Fabry-Perot multilayer structures consist of dielec- tric/reflector/magnetic/reflector/dielectric multilayer structures.
  • Preferred six-layer Fabry-Perot multilayer structures consist of absorb- er/dielectric/reflector/magnetic/dielectric/absorber multilayer structures.
  • Preferred seven-layer Fabry Perot multilayer structures consist of absorb- er/dielectric/reflector/magnetic/reflector/dielectric/absorber multilayer structures such as disclosed in US 4,838,648.
  • Preferred nine-layer Fabry-Perot multilayer structures consist of dielec- tric/absorber/dielectric/reflector/magnetic/dielectric/absorber/dielectric multilayer structures.
  • Preferred eleven-layer Fabry-Perot multilayer structures consist of absorb- er/dielectric/absorber/dielectric/reflector/magnetic/reflector/dielectric/absorber/dielectric/absorber multilayer structures.
  • the reflector layers are independently made from one or more selected from the group consisting of metals and metal alloys, preferably selected from the group consisting of reflective metals and reflective metal alloys, more preferably selected from the group consisting of aluminum (Al), silver (Ag), copper (Cu), gold (Au), platinum (Pt), tin (Sn), titanium (Ti), palladium (Pd), rhodium (Rh), niobium (Nb), chromium (Cr), nickel (Ni), and alloys thereof, even more preferably selected from the group consisting of aluminum (Al), chromium (Cr), nickel (Ni) and alloys thereof, and still more preferably aluminum (Al).
  • 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
  • the dielectric layers are independently made from one or more selected from the group consisting of metal fluorides such as magnesium fluoride (MgF2), aluminum fluoride (AIF3), cerium fluoride (CeFs), lanthanum fluoride (LaFs), sodium aluminum fluorides (e.g.
  • metal fluorides such as magnesium fluoride (MgF2), aluminum fluoride (AIF3), cerium fluoride (CeFs), lanthanum fluoride (LaFs), sodium aluminum fluorides (e.g.
  • NasAIFe neodymium fluoride
  • NaFs neodymium fluoride
  • SmFs samarium fluoride
  • BaF2 barium fluoride
  • CaF2 calcium fluoride
  • LiF lithium fluoride
  • metal oxides such as silicon oxide (SiO), silicium dioxide (SiC>2), titanium oxide (TiC>2), aluminum oxide (AI2O3), more preferably selected from the group consisting of magnesium fluoride (MgF2) and silicon dioxide (SiC>2) and still more preferably magnesium fluoride (MgF2).
  • the absorber layers are independently made from one or more selected from the group consisting of aluminum (Al), silver (Ag), copper (Cu), palladium (Pd), platinum (Pt), titanium (Ti), vanadium (V), iron (Fe) tin (Sn), tungsten (W), molybdenum (Mo), rhodium (Rh), Niobium (Nb), chromium (Cr), nickel (Ni), metal oxides thereof, metal sulfides thereof, metal carbides thereof, and metal alloys thereof, more preferably selected from the group consisting of chromium (Cr), nickel (Ni), metal oxides thereof, and metal alloys thereof, and still more preferably selected from the group consisting of chromium (Cr), nickel (Ni), and metal alloys thereof.
  • the magnetic layer comprises nickel (Ni), iron (Fe) and/or cobalt (Co); and/or a magnetic alloy comprising nickel (Ni), iron (Fe) and/or cobalt (Co); and/or a magnetic oxide comprising nickel (Ni), iron (Fe) and/or cobalt (Co).
  • the magnetic thin film interference pigment particles comprise a seven-layer Fabry-Perot absorber/dielectric/reflector/magnetic/reflector/dielectric/absorber multilayer structure consisting of a Cr/MgF2/AI/M/AI/MgF2/Cr multilayer structure wherein M is Ni, Fe or Co.
  • the magnetic thin film interference pigment particles may be multilayer pigment particles being considered as safe for human health and the environment and being based for example on five-layer Fabry-Perot multilayer structures, six-layer Fabry-Perot multilayer structures, seven-layer Fabry-Perot multilayer structures, nine-layer Fabry-Perot multilayer structures, eleven-layer Fabry-Perot multilayer structures and pigment particles having a multilayer structure combining one or more, or two or more, multilayer Fabry-Perot structures, wherein said pigment particles include one or more magnetic layers comprising a magnetic alloy having a substantially nickel-free composition including about 40 wt.% to about 90 wt.% iron, about 10 wt.% to about 50 wt.% chromium and about 0 wt.% to about 30 wt.% aluminum.
  • Typical examples of multilayer pigment particles being considered as safe for human health and the environment can be found in EP2402401 B1 whose content is hereby incorporated by reference in its
  • Suitable interference coated pigment particles comprising one or more magnetic materials include without limitation structures consisting of a substrate selected from the group consisting of a core coated with one or more layers, wherein at least one of the core or the one or more layers have magnetic properties.
  • suitable interference coated pigment particles comprise a core made of a magnetic material such as those described hereabove, said core being coated with one or more layers made of one or more metal oxides, or they have a structure consisting of a core made of synthetic or natural micas, layered silicates (e.g. talc, kaolin and sericite), glasses (e.g.
  • borosilicates silicon dioxides (SiC>2), aluminum oxides (AI2O3), titanium oxides (TiC>2), graphites and mixtures of two or more thereof, said core being coated with one or more magnetic materials. Furthermore, one or more additional layers such as coloring layers may be present.
  • the platelet-shaped magnetic or magnetizable pigment particles preferably have a size dso between about 2
  • the platelet-shaped magnetic or magnetizable pigment particles may be surface treated to protect them against any deterioration that may occur in the coating composition and coating layer and/or to facilitate their incorporation in said coating composition and coating layer; typically corrosion inhibitor materials and/or wetting agents may be used.
  • the platelet-shaped pigment particles are magnetic.
  • the platelet-shaped pigment particles are magnetizable.
  • the coating compositions of steps a) and a’) are exposed to the magnetic field of a magnetic assembly (230) or (230’) to magnetically orient at least a part of the platelet-shaped magnetic or magnetizable pigment particles (step b or b’).
  • the magnetic orientation in step b) and/or b’) may be single-step or multi-step, for example two-step.
  • Single-step orientation means that the printed coating composition comprising the magnetic or magnetizable pigment particles is subjected to the influence of a single magnetic assembly in step b) before curing in step c), or steps b’) and c’), as the case may be.
  • the magnetic orientation may be mono-axial, meaning that the pigment particles are substantially aligned along either the X-axis or the Y-axis (see Fig. 1).
  • the magnetic orientation may be bi-axial, meaning the pigment particles are substantially aligned along both their X- and Y-axes, or essentially the XY plane of the pigment particles are aligned in a common plane.
  • Bi-axial orientation of the pigment particles means that, when viewed face-on to the plane of alignment, the pigment particles will reflect light at a greater intensity as compared to a sample of non-aligned or only mono-axially aligned particles.
  • the pigment particles are bi-axially aligned, preferably with the XY-plane of the particles being substantially parallel to the plane of the substrate.
  • the substrate carrying the coating layer is moved through the inhomogeneous magnetic field of the magnetic assembly so that the platelet-shaped magnetic or magnetizable pigment particles are exposed to a magnetic field which is at least time- varying in direction thus bi-axially orienting at least part of said platelet-shaped magnetic or magnetizable pigment particles while the coating composition is still in a wet (i.e. not yet hardened) state.
  • the magnetic assembly allows to bi-axially orient the platelet-shaped magnetic or magnetizable pigment particles such that the platelet-shaped magnetic or magnetizable pigment particles form a sheet-like structure with their X and Y axes preferably substantially parallel to the substrate surface and are planarized in said two dimensions.
  • the magnetic assembly allows to bi-axially orient the platelet-shaped magnetic or magnetizable pigment particles such that the plateletshaped magnetic or magnetizable pigment particles have a first axis within the X-Y plane substantially parallel to the substrate surface and a second axis being substantially perpendicular to said first axis at a substantially non-zero elevation angle to the substrate surface.
  • the magnetic assembly allows to bi-axially orient the platelet-shaped magnetic or magnetizable pigment particles such that the platelet-shaped magnetic or magnetizable pigment particles have their X-Y plane substantially parallel to an imaginary spheroid surface.
  • the magnetic orientation in step b) and/or b’) may be multi-step, for example two-step, which comprises a first step of bi-axially orienting the platelet-shaped magnetic or magnetizable pigment particles, and a second step of re-orienting the platelet-shaped magnetic or magnetizable pigment particles according to a design.
  • the platelet-shaped magnetic or magnetizable pigment particles may also be aligned according to predetermined designs, determined by the design of the magnetic assembly.
  • the OEL comprises more than two motifs or coating layers comprising platelet-shaped magnetic or magnetizable pigment particles.
  • such references are understood to apply equally and independently to any magnetic orientation step carried out in the process of the invention [b”), b’”), etc.].
  • descriptions of the first and/or second motif and/or the first and/or second coating layer are understood to apply equally and independently to any motif or coating layer in the OEL comprising platelet-shaped magnetic or magnetizable pigment particles.
  • the platelet-shaped magnetic or magnetizable pigment particles are subjected to a two-step magnetic orientation, comprising step b1) in which a first magnetic assembly is used to substantially bi-axially orient the pigment particles (preferably parallel to the plane of the substrate), and step b2) in which the pigment particles are re-oriented and subjected to a second magnetic assembly designed to have a specific alignment pattern.
  • step b1) in which a first magnetic assembly is used to substantially bi-axially orient the pigment particles (preferably parallel to the plane of the substrate)
  • step b2) in which the pigment particles are re-oriented and subjected to a second magnetic assembly designed to have a specific alignment pattern.
  • the combination of a bi-axial orientation followed by a design-specific alignment results in a more visually striking effect than if the coating composition is simply subjected to a step of design-specific alignment.
  • Such a two-step orientation is shown schematically in steps b1) and b2), and steps b’1) and b’2) of Fig. 2.
  • step b1) and/or b’1) the first coating composition (210) is subjected to the influence of a magnetic assembly (230 or 230’), which has, for example, a structure as shown in Fig. 9. This results in bi-axial orientation of the pigment particles, substantially in the plane of the substrate (220).
  • step b2) and/or b’2) the bi-axially- oriented pigment particles are brought under the influence of a second magnetic assembly (240 or 240’), resulting in a design-specific orientation.
  • step b2) and step b’2) the coating composition (210 or 210’) is maintained under the influence of the bi-axially-orienting magnetic assembly (230 or 230’) while it is brought under the influence of the design-specific magnetic assembly (240 or 240’).
  • the position of the magnetic assembly (230 or 230’) and the magnetic assembly (240 or 240’) is not limited and depends on the choice and the design of the magnetic orientation pattern to be produced. Depending on the choice and the design of the magnetic orientation pattern to be produced, the magnetic assembly (230 or 230’) may be placed below the substrate (220) or above the coating layer (210 or 210’).
  • 230 and “240” independently either refer to single magnets or refer to assemblies comprising two or more magnets or refer to assemblies comprising one or more magnets and an engraved magnetic plate, or refer to assemblies comprising one or more magnets and a soft magnetic plate or refers to an assembly comprising a magnet and one or more pole pieces or comprising two or more magnets and one or more pole pieces, said magnetic assembly being selected according to the design of the magnetic orientation pattern of the motif.
  • the process of the invention comprises the magnetic orientation steps b) and b’) in which each of steps b) and b’) is a one-step orientation step.
  • the one-step orientation step may be a mono-axial orientation or a bi-axial orientation, or it may be design-specific orientation.
  • the process of the invention allows the preparation of OELs wherein the first and/or second motif bears one or more indicia
  • step b) and/or b’) consists of exposing the radiation-curable coating composition to an engraved magnetic plate (230 or 230’), wherein said engraved magnetic plate (230 or 230’) comprises one or more engravings (I) having the shape of indicia.
  • the engraved magnetic plate is preferably made from a permanent magnetic powder material and a polymer.
  • the engraved magnetic plate may typically be produced by an injection molding process or by metal or laser engraving.
  • Preferred permanent magnetic powder materials include cobalt, iron and their alloys, chromium dioxide, generic magnetic oxide spinels, generic magnetic garnets, generic magnetic ferrites including the hexaferrites such as calcium-, strontium-, and barium-hexaferrite (CaFe12019, SrFe12019, BaFe12019, respectively), generic alnico alloys, generic samarium-cobalt (SmCo) alloys, and generic rare-earth-iron-boron alloys (such as NdFeB), as well as the permanent- magnetic chemical derivatives thereof (such as indicated by the term generic) and mixtures thereof.
  • Plates made of a composite material comprising a polymer and a permanent magnetic powder are obtainable from many different sources, such as from Bomatec, Hbri, CH, ARNOLD® Magnetic Technologies (Plastiform®) or from Materiali Magnetici, Albairate, Milano, IT (Plastoferrite).
  • magnetic orientation in step b) and/or b’) is carried out by exposing the radiation-curable coating composition to a magnetic assembly such as those disclosed in US8,025,952 and EP1819525B1 and W02022/049024 A1 , wherein this effect is so-called “Venetian- blind” effect.
  • Fig. 5A-B of US7,047,883 discloses a magnetic assembly comprising two spaced apart magnets 84 placed on a magnetic base 62 with their North poles facing the substrate.
  • Fig. 9B of US7,047,883 discloses a magnetic assembly comprising a magnet 140 and the substrate comprising the coating layer is placed with an offset position relatively the magnet axes.
  • Fig. 5A-B of US7,047,883 discloses a magnetic assembly comprising two spaced apart magnets 84 placed on a magnetic base 62 with their North poles facing the substrate.
  • Fig. 9B of US7,047,883 discloses a magnetic assembly compris
  • FIG. 9C of US7,047,883 discloses a magnetic assembly comprising two magnets 142 and one magnet 142' having a diamondshaped cross section, wherein the two magnets 142 have their North pole facing the substrate while the intervening magnet 142' has its South pole facing the substrate.
  • Fig. 9D of US7,047,883 discloses a magnetic assembly comprising two magnets 144, and one magnet 144' having roof-shaped, hexagonal, rounded, trapezoidal, or other cross-sections, wherein the two magnets 144 have their North pole facing the substrate while the intervening magnet 144' has its South pole facing the substrate.
  • Fig. 9D of US7,047,883 discloses a magnetic assembly comprising two magnets 144, and one magnet 144' having roof-shaped, hexagonal, rounded, trapezoidal, or other cross-sections, wherein the two magnets 144 have their North pole facing the substrate while the intervening magnet 144' has its South pole facing the substrate.
  • 9E of US7,047,883 discloses a magnetic assembly comprising five magnets, the first magnet 142 being a diamond-shaped magnet with its North pole facing the substrate, the second magnet 146 being a rectangular magnet with its South pole facing the substrate, the third magnet 148 being a magnet with rounded top having its North pole facing the substrate, the fourth magnet 150 being a roof-shaped and having its South pole facing the substrate and the fifth magnet 152 being also a roof-shaped magnet and having its North pole facing the substrate.
  • FIG. 4A1 of W02022/04902A1 discloses a magnetic assembly comprising a bar dipole magnet and the particles are exposed to the magnetic field (magnetic field lines shown as lines with arrows pointing from the North Pole to the South Pole) of the magnetic assembly in one or more areas (shown as a dotted rectangle A) wherein the magnetic field is substantially homogeneous and wherein the magnetic field lines are substantially parallel to each other in said one or more areas.
  • 4A2 of W02022/0490241 A1 discloses a magnetic assembly comprising two bar dipole magnets (M1 , M2) having a same magnetic direction and an iron yoke (Y) and the particles are exposed to the magnetic field (magnetic field lines shown as lines with arrows pointing from the North Pole to the South Pole) of the magnetic assembly in one or more areas (shown as a dotted rectangle A) wherein the magnetic field is substantially homogeneous and wherein the magnetic field lines are substantially parallel to each other in said one or more areas.
  • M1 , M2 having a same magnetic direction and an iron yoke (Y) and the particles are exposed to the magnetic field (magnetic field lines shown as lines with arrows pointing from the North Pole to the South Pole) of the magnetic assembly in one or more areas (shown as a dotted rectangle A) wherein the magnetic field is substantially homogeneous and wherein the magnetic field lines are substantially parallel to each other in said one or more areas.
  • 6A-B of W02022/049024A1 discloses a magnetic assembly comprising a rectangular assembly comprising two bar dipole magnets (M1 , M2) and two pole pieces (P1 , P2) and the particles are exposed to the magnetic field (magnetic field lines shown as lines with arrows pointing from the North Pole to the South Pole) of the magnetic assembly in one or more areas (shown as a dotted rectangle A) wherein the magnetic field is substantially homogeneous and wherein the magnetic field lines are substantially parallel to each other in said area.
  • the process of the invention allows the preparation of OELs wherein the first and/or second motif exhibits a dynamic motion upon tilting said OEL, said dynamic motion of the OEL being a bright reflective vertical bar moving in a horizontal (left/right) direction when the OEL is tilted around a horizontal axis; wherein step b) and/or b’) consists of exposing the radiation- curable coating composition to a magnetic assembly such as those disclosed in W02020/160993A1 .
  • Figs 2-5 of W02020/160993A1 discloses magnetic assemblies comprising a) at least one dipole magnet (x40) being a square-shaped or rectangle-shaped dipole magnet having its magnetic axis oriented to be substantially parallel to a substrate and b) a combination of n sets of spaced apart bar dipole magnets (x30-a1 , x30-a2) with n being an integer equal to or bigger than 1 , wherein each of said bar dipole magnets (x30-a1 , x30-a2) has its North-South magnetic axis substantially parallel to the substrate surface, wherein, for each set of said n sets, the bar dipole magnets (x30-a1 , x30-a2) have their North pole pointing in a same direction and are substantially parallel to each other; wherein the vector sum H1 of the magnetic axes of the bar dipole magnets (x30-a1 , x30-a2) and the vector sum H2 of the at least one dipole magnet (x40) form
  • the process of the invention allows the preparation of OELs wherein the first and/or second motif exhibits a dynamic motion upon tilting said OEL, said dynamic movement of the OEL being a bright reflective horizontal bar moving in a vertical direction (up/down) when the OEL is tilted around a horizontal axis; wherein said step b) and/or step b’) consists of exposing the radiation curable coating composition to a magnetic assembly such as those disclosed in WO2014/198905A2.
  • Figs 2-5 of WO2014/198905A2 disclose magnetic assemblies comprising: a) a bar dipole magnet (M1) and a pair of bar dipole magnets (M2) and (M3), said bar dipole magnets (M1), (M2) and (M3) having their North-South axis substantially parallel to the substrate and the same magnetic North-South direction, wherein a1) said bar dipole magnet (M1) is disposed below the substrate and said pair of bar dipole magnets (M2) and (M3) are disposed below the bar dipole magnet (M1) apart from each other; or a2) said pair of bar dipole magnets (M2) and (M3) are disposed below the substrate and apart from each other, and said bar dipole magnet (M1) is disposed below said pair of bar dipole magnets (M2) and (M3); or b) a pair of bar dipole magnets (M4) and (M5) and a pole piece (Y), said pair of bar dipole magnets (M4) and (M5) having their North-South axis substantially parallel
  • the process of the invention allows the preparation of OELs wherein the first and/or second motif exhibits a dynamic motion upon tilting said OEL, said dynamic movement being a nested multi-loop-shaped body moving when the OEL is tilted; wherein step b) and/or step b’) consists of exposing the radiation-curable coating composition to a magnetic assembly such as those disclosed in W02014/108303A2.
  • Disclosed magnetic assemblies of W02014/108303A2 comprise one of the following: a) at least one dipole magnet being a loop-shaped magnet defining a loop and having a magnetic axis oriented to be substantially perpendicular to the substrate and a pole piece (x60) being disposed below the at least one dipole magnet and within the loop of said at least one dipole magnet and having one or more protrusions disposed within the loop of the at least one dipole magnet (see for example Figs 3-5 of W 2014/108303A2); or b) at least one dipole magnet having a magnetic axis oriented to be substantially perpendicular to the substrate, an additional dipole magnet having a magnetic axis oriented to be substantially perpendicular to the substrate and two or more pole pieces, wherein said at least one dipole magnet and additional magnet have the same magnetic direction and are provided in different distances from substrate, wherein said two or more pole pieces are arranged in the space between the magnets and in contact therewith and wherein at least one of the two or
  • At least one dipole magnet having a magnetic axis oriented to be substantially perpendicular to the substrate, a plate-like-shaped pole piece being disposed below and in contact with the at least one dipole magnet, and one or more loop-shaped pole pieces being disposed on top the at least one dipole magnet, wherein a central pole piece of said one or more loop-shaped pole pieces is in contact with the at least one dipole magnet, and wherein said plate-like-shaped pole piece may comprise one or more protrusions laterally and spaced apart surrounding the at least one dipole magnet (see for example Fig. 7 of W02014/108303A2).
  • W02014/108303A2 also disclose spinneable magnetic assemblies comprising a) at least two bar dipole magnets having their magnetic axis substantially perpendicular to the substrate (see Figs 8-10 and 13-14 of WO2014/108303A2) or comprising b) at least four bar dipole magnets having their magnetic axis substantially parallel to the substrate (see Figs 11 , 12 and 15 of W02014/108303A2).
  • the process of the invention allows the preparation of OELs wherein the first and/or second motif exhibits a dynamic motion upon tilting said OEL, said dynamic movement being a loop-shaped body having a size that varies when the OEL is tilted; wherein said step b) and/or step b’) consists of exposing the radiation-curable coating composition to a magnetic assembly such as those disclosed in W02017/064052A1 , W02017/080698A1 and WO2017/148789A1.
  • Disclosed magnetic assemblies of W02017/064052A1 , W02017/080698A1 and WO2017/148789A1 comprise one of the following: at least one dipole magnet (x40) being either a single bar dipole magnet having a North-South magnetic axis substantially parallel to a substrate or a combination of two or more bar dipole magnets having a resulting North-South magnetic axis substantially parallel to the substrate and b) a loop-shaped magnetic-field generating device (x30) being either a single loop-shaped dipole magnet having a North- South magnetic axis substantially perpendicular to the substrate or a combination of two or more dipole magnets disposed in a loop-shaped arrangement and having a resulting North-South magnetic axis substantially perpendicular to the substrate (see for example Figs 1-4 of W02017/064052A1), or at least one dipole magnet (x40) being either a single dipole magnet having a magnetic axis substantially parallel to the substrate or a combination of two
  • the process of the invention allows the preparation of OELs wherein the first and/or second motif exhibits a dynamic motion upon tilting said OEL, said dynamic movement being one or more loop-shaped bodies having a shape that varies when the OEL is tilted; wherein step b) and/or step b’) consists of exposing the radiation-curable coating composition to a magnetic assembly such as those disclosed in WO2018/054819A1 .
  • the disclosed magnetic assembly of WO2018/054819A1 comprises a loop-shaped magnetic-field generating device (x31) being either a single loop-shaped magnet (x31) or a combination of two or more dipole magnets (x31) disposed in a loop-shaped arrangement, the loop-shaped magnetic-field generating device (x31) having a radial magnetization; and a single dipole magnet (x32) having a magnetic axis substantially perpendicular to the substrate surface or two or more dipole magnets (x32), each of said two or more dipole magnets (x32) having a magnetic axis substantially perpendicular to the substrate surface, wherein the single dipole magnet (x32) or the two or more dipole magnets (x32) are located partially within, within or above the loop defined by the single loop-shaped magnet (x31) or partially within, within or above the loop defined by the two or more dipole magnets (x31) disposed in the loop-shaped arrangement, and wherein the South pole of said single dipole magnet
  • the process of the invention allows the preparation of OELs wherein the first and/or second motif exhibits a dynamic motion upon tilting said OEL, said dynamic movement being a moon crescent moving and rotating when the OEL is tilted; wherein step b) and/or step b’) consists of exposing the radiation-curable coating composition to a magnetic assembly such as those disclosed in WO2019/215148A1 .
  • Disclosed magnetic assemblies of WO2019/215148A1 comprise a) a first magnetic-field generating device (x30) having its North-South magnetic axis substantially perpendicular to the substrate surface and having length L1 , b) a second magnetic-field generating device (x40) having its North-South magnetic axis substantially perpendicular to the substrate and having a length L3, and c) a flat pole piece (x50) lacking any protrusions or projections extending outside the surface of said pole piece and having a length L5, wherein the first magnetic-field generating device and the second magnetic-field generating device have a same magnetic field direction, wherein the first magnetic-field generating device faces the substrate and is disposed above the flat pole piece), wherein the second magnetic-field generating device faces the environment and is disposed below the flat pole piece, wherein the length L1 of the first magnetic-field generating device is smaller than the length L3 of the second magnetic-field generating device, wherein the length L1 of the first magnetic-field generating device
  • the process of the invention allows the preparation of OELs wherein the first and/or second motif exhibits a dynamic motion upon tilting said OEL, said dynamic movement being a loop-shaped body surrounded by one or more loop-shaped bodies having their shape and/or their brightness varying when the OEL is tilted; wherein step b) and/or step b’) consists of exposing the radiation-curable coating composition to a magnetic assembly such as those disclosed in W02020/193009A1 .
  • Disclosed magnetic assemblies of W02020/193009A1 comprise a) a combination of three or more first dipole magnets (x31-ai), each of said first dipole magnets having its center disposed on a loop in a plane parallel to the substrate, wherein said first dipole magnets (x31- ai) have their magnetic axes oriented to be substantially parallel to the substrate and b) at least one second dipole magnet (x41) having its magnetic axis oriented to be substantially perpendicular to the substrate and being arranged to have a projection of its center on the substrate be located at a projection point within the loop, wherein the at least one second dipole magnet (x41) is disposed above the combination of three or more first dipole magnets (x31-ai), wherein angles ai are formed between each of the vectors C x41 C x31-ai (C x44 C x31-al , C x41 C x31-a2 , C x41 C x31-a3 ) and
  • the process of the invention allows the preparation of OELs wherein the first and/or second motif exhibits a dynamic movement being a pattern of bright areas and dark areas moving when the OEL is tilted; wherein the step b) and/or step b’) consists of exposing the radiation curable coating composition to a magnetic assembly such as those disclosed in WO2013/167425A1 and W02021/083809A1 .
  • the straight lines eq and ft forming a grid, wherein at least two additional dipole magnets (x31) are disposed on one of the straight lines oq and at least two other additional dipole magnets (x31) are disposed on another one of the straight lines oq , wherein the magnetic axes of the additional dipole magnets are oriented substantially parallel to the substantially parallel straight lines oq, wherein the at least one dipole magnet (x40) is disposed below the combination comprising at least four dipole magnets (x31).
  • each straight line oq and a vector H of the magnetic axis of the at least one dipole magnet (x41) is substantially parallel or substantially perpendicular with respect to each other and the OEL exhibits a dynamic movement being a pattern of bright areas and dark areas moving when the substrate carrying said OEL is tilted, said pattern of bright areas and dark areas moving in the same direction as the tilting direction.
  • each straight line oq and a vector H of the magnetic axis of the at least one dipole magnet (x41) is substantially non-parallel and substantially non-perpendicular with respect to each other OEL, preferably wherein each straight line oq and the vector sum H of the magnetic axis of the at least one dipole magnet (x41) form an angle y in the range from about 20° to about 70° or in the range from about 110° to about 160° or in the range from about 200° to about 250°, or in the range from about 290° to about 340°; and the OEL exhibits a dynamic movement being a pattern of bright areas and dark areas moving not only in a diagonal direction when the substrate carrying said OEL is tilted around a vertical axis but also moving in a diagonal direction when the substrate carrying said OEL is tilted around a horizontal axis (in other words, the OEL provides the optical impression of a plurality of dark and a plurality of bright spots that are moving when the substrate carrying said OEL
  • the process of the invention allows the preparation of OELs wherein the first and/or second motif exhibits a dynamic movement being a pattern of bright areas and dark areas moving when the OEL is tilted; wherein step b) and/or step b’) consists of exposing the radiation curable coating composition to a magnetic assembly such as those disclosed in W02021/083808A1 .
  • the process of the invention allows the preparation of OELs wherein the first and/or second motif exhibits a dynamic motion upon tilting said OEL, said dynamic movement being a change from dark to light of two areas when the OEL is tilted (effect so-called flipflop); wherein said at least one of steps b) and/or b’) consists of exposing the radiation-curable coating composition to a magnetic assembly such as those disclosed in Fig. 1 , 3 and 6 of US2005/0106367.
  • the process of the invention allows the preparation of OELs wherein the first and/or second motif exhibits a dynamic motion upon tilting said OEL, said dynamic movement being at least one comet-shaped spot rotating around said center of rotation upon tilting said OEL, wherein step b) and/or step b’) consists of exposing the radiation-curable coating composition to a magnetic assembly such as those disclosed in WO2019/038371 A1 , W02019/038370A1 and WO2019/038369A1.
  • Disclosed magnetic assemblies of WO2019/038371 A1 , W02019/038370A1 and WO2019/038369A1 comprise at least one of the following: a) first magnetic-field generating device (x30) and b) a second magnetic-field generating device (x40), wherein said first magnetic-field generating device (x30) and said second magnetic-field generating device (x40) have mutually skew magnetic axes, wherein said first magnetic-field generating device (x30) has its magnetic axis substantially perpendicular to the axis of spinning and said second magnetic- field generating device (x40) has its magnetic axis substantially perpendicular to the axis of spinning and wherein the projection of the magnetic axis of the first magnetic-field generating device (x30) and the projection of the magnetic axis of the second magnetic-field generating device (x40) along the axis of spinning onto a plane perpendicular to the axis of spinning form an angle (Q) either in the range
  • platelet-shaped magnetic or magnetizable pigment particles are orientated in such a way that only their main axis is constrained by the magnetic field
  • a bi-axial orientation means that the platelet-shaped magnetic or magnetizable pigment particles are made to orientate in such a way that their two main axes are constrained.
  • needle-shaped pigment particles which can be considered as one-dimensional particles
  • platelet-shaped pigment particles have an X-axis and an Y-axis defining a plane of predominant extension of the particles.
  • platelet-shaped pigment particles may be considered to be two-dimensional particles due to the large aspect ratio of their dimensions as can be seen in Fig. 1. As shown in Fig.
  • a platelet-shaped pigment particle can be considered as a two-dimensional structure wherein the dimensions X and Y are substantially larger than dimension Z.
  • Platelet-shaped pigment particles are also referred to in the art as oblate particles or flakes. Such pigment particles may be described with a main axis X corresponding to the longest dimension crossing the pigment particle and a second axis Y perpendicular to X which also lies within said pigment particles. Carrying out a bi-axial orientation leads to platelet-shaped magnetic or magnetizable pigment particles having two main axes constrained; i.e. bi-axially oriented neighboring platelet-shaped magnetic pigment particles are close to each other in space and are essentially parallel to each other.
  • bi-axial orientation aligns the planes of the platelet-shaped magnetic or magnetizable pigment particles so that the planes of said pigment particles are oriented to be essentially parallel relative to the planes of neighboring (in all directions) platelet-shaped magnetic or magnetizable pigment particles.
  • the magnetic assembly described hereafter bi-axially orients the platelet-shaped magnetic or magnetizable pigment particles such that the platelet-shaped magnetic or magnetizable pigment particles form a sheet-like structure with their X and Y axes preferably substantially parallel to the substrate (220) surface and are planarized in said two dimensions.
  • the magnetic assembly described hereafter bi-axially orients the platelet-shaped magnetic or magnetizable pigment particles such that the platelet-shaped magnetic or magnetizable pigment particles have a first axis within the X-Y plane substantially parallel to the substrate (220) surface and a second axis being substantially perpendicular to said first axis at a substantially non-zero elevation angle to the substrate surface.
  • the magnetic assembly described hereafter bi-axially orients the platelet-shaped magnetic or magnetizable pigment particles such that the platelet-shaped magnetic or magnetizable pigment particles have their X-Y plane substantially parallel to an imaginary spheroid surface.
  • the process of the invention allows the preparation of OELs wherein the first and/or second motif comprises bi-axially oriented platelet-shaped magnetic or magnetizable pigment particles; wherein step b) and/or step b’) consists of exposing the radiation- curable coating composition to a magnetic assembly such as those described in EP2157141A1.
  • the disclosed magnetic assemblies of EP2157141A1 provide a magnetic field that changes its direction while the platelet-shaped magnetic or magnetizable pigment particles move through said assemblies, forcing the platelet-shaped magnetic or magnetizable pigment particles to rapidly oscillate until both main axes become parallel to the substrate, i.e.
  • the platelet-shaped magnetic or magnetizable pigment particles oscillate until they come to a stable sheet-like formation with their X and Y axes parallel to the substrate to the substrate and are planarized in said two dimensions.
  • the magnetic assembly comprises a linear arrangement of at least three magnets that are positioned in a staggered fashion or in zigzag formation, said at least three magnets being on opposite sides of a feedpath where magnets at the same side of the feedpath have the same polarity, which is opposed to the polarity of the magnet(s) on the opposing side of the feedpath in a staggered fashion.
  • the magnetic assembly comprises a) a first magnet and a third magnet on a first side of a feedpath and b) a second magnet between the first and third magnets on a second opposite side of the feedpath, wherein the first and third magnets have a same polarity and wherein the second magnet has a complementary polarity to the first and third magnets.
  • the magnetic assembly further comprises a fourth magnets on the same side of the feedpath as the second magnet, having the polarity of the second magnet and complementary to the polarity of the third magnet.
  • the process of the invention allows the preparation of OELs wherein the first and/or second motif comprises bi-axially oriented platelet-shaped magnetic or magnetizable pigment particles; wherein step b) and/or step b’) consists of exposing the radiation- curable coating composition to a magnetic assembly consisting of a linear permanent magnet Halbach array, i.e. assemblies comprising a plurality of magnets with different magnetization directions and cylinder devices.
  • a linear permanent magnet Halbach array i.e. assemblies comprising a plurality of magnets with different magnetization directions and cylinder devices.
  • the magnetic field produced by such a Halbach array has the properties that it is concentrated on one side while being weakened almost to zero on the other side.
  • Linear Halbach arrays are disclosed for example in WO 2015/086257 A1 and WO 2018/019594 A1 and Halbach cylinder devices are disclosed in EP3224055B1.
  • the process of the invention allows the preparation of OELs wherein the first and/or second motif comprises bi-axially oriented platelet-shaped magnetic or magnetizable pigment particles; wherein said at least one of steps b) and b’) consists of exposing the radiation curable coating composition to spinning magnetic assemblies at an appropriate speed.
  • spinning magnetic assemblies are assemblies comprising one or more disc-shaped spinning magnets or magnetic assemblies that are essentially magnetized along their diameter, magnetic assemblies consisting of spinning magnets or magnetic-field generating devices are described in US2007/0172261 A1 , said spinning magnets or magnetic-field generating devices generating radially symmetrical time-variable magnetic fields, allowing the bi-axial orientation of pigment particles.
  • CN 102529326 B discloses examples of magnetic assemblies comprising spinning magnets that might be suitable for bi-axially orienting pigment particles.
  • suitable magnetic assemblies are shaft-free disc-shaped spinning magnetic assemblies constrained in a housing made of non-magnetic, preferably non-conducting, materials and are driven by one or more magnet-wire coils wound around the housing. Examples of such shaft-free disc-shaped spinning magnetic assemblies are disclosed in WO2015/082344A1 , WO2016/026896A1 and
  • the process of the invention allows the preparation of OELs, wherein step b) and/or step b’) consists of exposing the radiation-curable coating composition to the resultant magnetic field of a combination of a magnetic assembly described hereabove for bi-axially orienting pigment particles and a soft magnetic plate comprising one or more indentations (I) and/or one or more voids (V) and/or one or more protrusions (P).
  • the soft magnetic plate comprises one or more soft magnetic materials, i.e. materials having a low coercivity and a high permeability p.
  • Soft magnetic materials are described, for example, in the following handbooks: (1) Handbook of Condensed Matter and Materials Data, Chap. 4.3.2, Soft Magnetic Materials, p. 758-793, and Chap. 4.3.
  • the soft magnetic plate may either be a plate made of one or more metals, alloys or compounds of high magnetic permeability (hereafter referred as “soft magnetic metal plate”) or a plate made of a composite comprising soft magnetic particles dispersed in a non-magnetic material (hereafter referred as “soft magnetic composite plate”).
  • the soft magnetic metal plate is made of one or more soft magnetic metals or alloys easily workable as sheets or threads.
  • the soft magnetic metal plate is made from one or more materials selected from the group consisting of iron, cobalt, nickel, nickel-molybdenum alloys, nickel-iron alloys (permalloy or supermalloy-type materials), cobalt-iron alloys, cobalt-nickels alloys iron-nickel-cobalt alloys (Fernico-type materials), Heusler-type alloys (such as Cu2MnSn or Ni2MnAI), low silicon steels, low carbon steels, silicon irons (electrical steels), iron-aluminum alloys, iron-aluminum-silicon alloys, amorphous metal alloys (e.g.
  • alloys like Metglas®, iron-boron alloys), nanocrystalline soft magnetic materials (e.g. Vitroperm®) and combinations thereof, more preferably selected from the group consisting of iron, cobalt, nickel, low carbon steels, silicon irons, nickel-iron alloys and cobalt-iron alloys and combinations thereof.
  • One or both of the first and second coating compositions and the first and second coating layers comprises at least one luminescent pigment or dye.
  • the at least one luminescent pigment or dye may be inorganic (inorganic host crystals or glasses doped with luminescent ions), organic or organometallic (complexes of luminescent ion(s) with organic ligand(s)) substances.
  • Luminescent pigments or dyes can absorb certain types of energy acting upon them and subsequently emit at least partially this absorbed energy as electromagnetic radiation. Luminescent pigments or dyes are detected by exposing them to a certain wavelength of light and analyzing the emitted light.
  • Down-converting luminescent compounds absorb electromagnetic radiation at a higher frequency (shorter wavelength) and emit radiation at a lower frequency (longer wavelength). Up-converting luminescent compounds absorb electromagnetic radiation at a lower frequency and emit radiation at a higher frequency.
  • the luminescent pigment or dye for use in the invention emits in the visible range (400- 800 nm) upon irradiation with UV light (10-400 nm, more preferably 300-400 nm).
  • Luminescent pigments and dyes for the invention are known in the art and may be selected from the group consisting of naphthalmides, coumarins, rhodamines, fluroresceins, distyryl biphenyls, stilbenes, cyanines, phthalocyanines, xanthenes, thioxanthenes, naphtholactams, azlactones, methanes, oxazines, pyrazolines, polypyridyl-ruthenium complexes, polypyridyl-phenazine-ruthenium complexes, platinum- porphyrin complexes, long-life europium and terbium complexes and mixtures thereof.
  • Typical examples of dyes suitable for the invention are e.g. Solvent Yellow 44, Solvent Yellow 94, Solvent Yellow 160, Basic Yellow 40, Basic Red 1 , Basic Violet 10, Acid Red 52, Yellow s790, fluorescein isothiocyanate, tris(2,2’-bipyridyl)-ruthenium chloride, tris(1 ,10-phenanthroline)-ruthenium chloride, octaethyl-platinum-porphyrin.
  • Luminescent materials in pigment form have been widely used in inks (see US6565770, W02008/033059A2 and W02008/092522A1).
  • luminescent materials include among others sulfides, oxysulfides, phosphates, vanadates, etc. of non-luminescent cations, doped with at least one luminescent cation chosen from the group consisting of transition-metal and the rare-earth ions; rare earth oxysulfides and rare-earth metal complexes such as those described in W02009/005733A2 or in US7108742.
  • inorganic materials include without limitation La2O2S:Eu, ZnS Mn, and YVC Nd.
  • the first and/or second coating compositions and the first and/or second coating layers preferably comprise one or more luminescent pigments or dyes in an amount from at or about 0.1 to at or about 40 wt%, more preferably from at or about 0.5 to at or about 10 wt%, particularly preferably from at or about 0.5 to at or about 5 wt%, the wt% being based on the total weight of the coating composition.
  • the first coating composition and the first coating layer comprise at least one luminescent pigment or dye
  • the second coating composition and the second coating layer do not comprise a luminescent pigment or dye.
  • first coating composition and the first coating layer do not comprise a luminescent pigment or dye
  • second coating composition and the second coating layer comprise at least one luminescent pigment or dye
  • first and second coating compositions and the first and second coating layers both comprise at least one luminescent pigment or dye.
  • Curing of the first and second coating compositions [steps c) and c’)] results in fixing the platelet-shaped magnetic or magnetizable pigment particles. Subsequently to or partially simultaneously with, preferably partially simultaneously with the step or steps of orienting the plateletshaped magnetic or magnetizable pigment particles (step b and/or step b’), the orientation of the platelet-shaped magnetic or magnetizable pigment particles is fixed or frozen (step c and/or step c’) by curing.
  • the coating compositions therefore have a first state, i.e.
  • a liquid or pasty state wherein the composition is not yet hardened and wet or soft enough, so that the platelet-shaped magnetic or magnetizable pigment particles dispersed in the compositions are freely movable, rotatable and orientable upon exposure to a magnetic field, and a second hardened (e.g. solid or solid-like) state, wherein the platelet-shaped magnetic or magnetizable pigment particles are fixed or frozen in their respective positions and orientations.
  • Such a first and second state is preferably provided by using a certain type of coating composition.
  • the components of the first radiation-curable coating composition other than the platelet-shaped magnetic or magnetizable pigment particles may take the form of an ink or coating composition such as those which are used in security applications, e.g. for banknote printing.
  • the aforementioned first and second states can be provided by using a material that shows an increase in viscosity in reaction to a stimulus such as for example a temperature change or an exposure to an electromagnetic radiation. That is, when the fluid binder material is hardened or solidified, said binder material converts into the second state, i.e.
  • ingredients comprised in an ink or coating composition to be applied directly or indirectly onto a substrate and the physical properties of said ink or coating composition must fulfill the requirements of the process used to transfer said ink or coating composition. Consequently, the binder material comprised in the coating compositions is typically chosen among those known in the art and depends on the coating or printing process used to apply the ink or coating composition and the chosen hardening process.
  • the curing steps c) and c’) involve a chemical reaction, for instance curing, which is not reversed by a simple temperature increase (e.g. up to 80°C) that may occur during a typical use of a security document.
  • the term “curing” or “curable” refers to processes including the chemical reaction, crosslinking or polymerization of at least one component in the applied coating composition in such a manner that it turns into a polymeric material having a greater molecular weight than the starting substances.
  • the curing causes the formation of a stable three-dimensional polymeric network.
  • Such a curing is generally induced by applying an external stimulus to the composition (i) after its application (step a) and (ii) subsequently to or partially simultaneously with the orientation (step b and step b’) of at least part of the platelet-shaped magnetic or magnetizable pigment particles (step c and/or step c’).
  • the curing step of the first coating layer is carried out partially simultaneously with the orientation (step b and/or step b’) of at least a part of the platelet-shaped magnetic or magnetizable pigment particles (step c and/or step c’).
  • UV- Vis curing advantageously leads to an instantaneous increase in viscosity of the first and second radiation-curable coating composition after exposure to irradiation, thus preventing any further movement of the pigment particles and in consequence any loss of information after the magnetic orientation step.
  • the curing step is carried out by irradiation with UV- visible light (i.e. UV-Vis light radiation curing) or by E-beam (i.e. E-beam radiation curing), more preferably by irradiation with UV-Vis light since UV-Vis curing advantageously allows very fast curing processes.
  • the first or second radiation-curable coating compositions preferably the first and second UV-Vis-curable coating compositions, independently comprise one or more compounds selected from the group consisting of radically-curable compounds and cationically-curable compounds.
  • the coating compositions may be hybrid systems and comprise a mixture of one or more cationically- curable compounds and one or more radically-curable compounds.
  • Cationically-curable compounds are cured by cationic mechanisms typically including the activation by radiation of one or more photoinitiators which liberate cationic species, such as acids, which in turn initiate the curing to react and/or cross-link the monomers and/or oligomers to thereby harden the coating composition.
  • Radically- curable compounds are cured by free radical mechanisms typically including the activation by radiation of one or more photoinitiators, thereby generating radicals which in turn initiate the polymerization to harden the coating composition.
  • photoinitiators might be used.
  • free radical photoinitiators are known to those skilled in the art and include without limitation acetophenones, benzophenones, benzyldimethyl ketals, alpha-aminoketones, alpha-hydroxyketones, phosphine oxides and phosphine oxide derivatives, as well as mixtures of two or more thereof.
  • Suitable examples of cationic photoinitiators are known to those skilled in the art and include without limitation onium salts such as organic iodonium salts (e.g. diaryl iodoinium salts), oxonium (e.g. triaryloxonium salts) and sulfonium salts (e.g. triarylsulphonium salts), as well as mixtures of two or more thereof.
  • onium salts such as organic iodonium salts (e.g. diaryl iodoinium salts), oxonium (e.g. triaryloxonium salts) and sulfonium salts (e.g. triarylsulphonium salts), as well as mixtures of two or more thereof.
  • organic iodonium salts e.g. diaryl iodoinium salts
  • oxonium e.g. triaryloxonium salts
  • sulfonium salts e.g. triaryl
  • Suitable photosensitizers include without limitation isopropyl-thioxanthone (ITX), 1-chloro-2-propoxy-thioxanthone (CPTX), 2- chloro-thioxanthone (CTX) and 2,4-diethyl-thioxanthone (DETX) and mixtures of two or more thereof.
  • the one or more photoinitiators comprised in the radiation-curable coating compositions are preferably present in a total amount from about 0.1 wt% to about 20 wt%, more preferably about 1 wt% to about 15 wt%, the weight percents being based on the total weight of the first and second radiation-curable coating compositions, respectively.
  • the first and second coating compositions are radical-curing coating compositions.
  • the first and second coating compositions comprise acrylates, particularly preferably polyacrylates, i.e. molecules bearing two or more acrylate functionalities.
  • the first and second radiation-curable coating compositions may further independently comprise one or more additives including without limitation compounds and materials which are used for adjusting physical, rheological and chemical parameters of the composition such as the viscosity (e.g. solvents and surfactants), the consistency (e.g. anti-settling agents, fillers and plasticizers), the foaming properties (e.g. antifoaming agents), the lubricating properties (waxes), UV reactivity and stability (photosensitizers and photostabilizers) and adhesion properties, etc.
  • Additives may be present in the coating compositions in amounts and in forms known in the art, including in the form of so-called nano-materials where at least one of the dimensions of the particles is in the range of 1 to 1000 nm.
  • the first and second radiation-curable coating compositions may be independently prepared by dispersing or mixing the platelet-shaped magnetic or magnetizable pigment particles and/or the at least one luminescent pigment or dye and/or the one or more additives when present in the presence of the binder material, thus forming liquid compositions.
  • the one or more photoinitiators may be added to the composition either during the dispersing or mixing step of all other ingredients or may be added at a later stage, i.e. after the formation of the liquid coating composition.
  • the process for producing the OEL of the invention comprises partially simultaneously with step b) and/or step b’) or subsequently to step b) and/or step b’), preferably partially simultaneously, a step of curing step c) and step c’) of the first and second radiation-curable coating compositions.
  • the step of curing the first and second coating compositions allows the platelet-shaped magnetic or magnetizable pigment particles to be fixed in their adopted positions and orientations in a desired pattern to form the OEL, thereby transforming the first radiation-curable coating composition to a second state.
  • the time from the end of step b) and/or step b’) to the beginning of step c) and/or step c’) is preferably relatively short in order to avoid any de-orientation and loss of information.
  • the time between the end of step b) and/or step b’) and the beginning of step c) and/or step c’) is less than 1 minute, preferably less than 20 seconds, further preferably less than 5 seconds. It is particularly preferable that there be essentially no time gap between the end of the orientation step b) and/or step b’) and the beginning of the curing step c) and/or step c’), i.e.
  • step c) and/or step c’) follow immediately after step b) and/or step b’) or already start while step b) and/or step b’) is still in progress (partially simultaneously).
  • step b) and/or step b’ it must be understood that curing becomes effective after the orientation so that the platelet-shaped magnetic or magnetizable pigment particles orient before the complete or partial curing of the OEL.
  • the curing steps c) and c’) may be performed by using different means or processes depending on the binder material comprised in the first coating composition and the second coating composition that also comprise the platelet-shaped magnetic or magnetizable pigment particles.
  • the curing steps generally may be any step that increases the viscosity of the radiation-curable coating composition such that a substantially solid material adhering to the substrate is formed.
  • the curing steps may involve a physical process based on the evaporation of a volatile component, such as a solvent, and/or water evaporation (i.e. physical drying).
  • a volatile component such as a solvent, and/or water evaporation (i.e. physical drying).
  • hot air, infrared or a combination of hot air and infrared may be used.
  • the curing steps may include a chemical reaction, such as a curing, polymerizing or cross-linking of the binder and optional initiator compounds and/or optional cross-linking compounds comprised in the radiation-curable coating composition.
  • Such a chemical reaction may be initiated by heat or IR irradiation as outlined above for the physical hardening processes, but may preferably include the initiation of a chemical reaction by a radiation mechanism including without limitation Ultraviolet-Visible light radiation curing (hereafter referred as UV-Vis curing) and electronic beam radiation curing (E-beam curing); oxypolymerization (oxidative reticulation, typically induced by joint action of oxygen and one or more catalysts preferably selected from the group consisting of cobalt-containing catalysts, vanadium-containing catalysts, zirconium-containing catalysts, bismuth-containing catalysts and manganese-containing catalysts); cross-linking reactions or any combination thereof.
  • a radiation mechanism including without limitation Ultraviolet-Visible light radiation curing (hereafter referred as UV-Vis curing) and electronic beam radiation curing (E-beam curing); oxypolymerization (oxidative reticulation, typically induced by joint action of oxygen and one or more
  • Radiation curing is particularly preferred, and UV-Vis light radiation curing is even more preferred, since these technologies advantageously lead to very fast curing processes and hence drastically decrease the preparation time of any article comprising the OEL of the invention.
  • radiation curing has the advantage of producing an almost instantaneous increase in viscosity of the coating composition after exposure to the curing radiation, thus minimizing any further movement of the particles. In consequence, any loss of orientation after the magnetic orientation step can essentially be avoided.
  • Particularly preferred is radiation-curing by photo-polymerization, under the influence of actinic light having a wavelength component in the UV or blue part of the electromagnetic spectrum (typically 200 nm to 650 nm; more preferably 200 nm to 420 nm).
  • Suitable curing units for the curing steps may comprise a high-power light-emitting-diode (LED) lamp, or an arc discharge lamp, such as a medium-pressure mercury arc (MPMA) or a metal-vapor arc lamp, as the source of the actinic radiation.
  • LED light-emitting-diode
  • MPMA medium-pressure mercury arc
  • a metal-vapor arc lamp as the source of the actinic radiation.
  • UV-LED lamps emit radiation in the UV-A region and/or visible (Vis) region, e.g. in the range from about 350 nm to about 470 nm.
  • current UV-LED and Vis-LED lamps emit quasi monochromatic radiation, i.e.
  • the steps c) and c’)) are carried out by exposing the first coating layer (210) and the second coating layer (211), respectively, to UV light with an LED curing unit, preferably to one or more wavelengths between about 355 nm and about 415 nm, more preferably by exposure to UV light at 365 nm and/or 385 nm and/or 395 nm, emitted from the LED curing unit.
  • the first and second coating compositions comprise polyacrylates, and at least one photoinitiator, and curing is carried out using UV-Vis light.
  • the first coating layer may be subjected to customization to produce OELs further exhibiting one or more indicia, wherein said customization step is carried out after the orientation step b), and prior to curing step c) and/or step c’).
  • the customization step is preferably carried out by applying a liquid coating composition on top of the coating layer which is still is a wet state (a wet-on-wet process), said application being carried out by a contactless fluid microdispensing process such as disclosed in WO2021/259527A1 .
  • the first motif and the second motif are at least partially intercalated, and the first motif comprises at least n elements of a same first shape and the second motif comprises m elements of a second shape, n and m being the same or different and being at least two, and wherein at least one of the elements of the first motif is at least partially adjacent to two elements of the second motif and/or at least one of the elements of the second motif is at least partially adjacent to two elements of the first motif.
  • An example of a process for carrying this out is shown schematically in Fig. 6, and exemplary screens/motifs are shown in Fig. 5b, where the first motif is depicted in part a) and the second motif is depicted in part b).
  • Example E2 is another example of this kind of embodiment, with the result of the intercalation of the first motif and the second motif shown in Fig. 12.
  • the OELs comprise a first motif, in the form of a cured first coating layer (210) comprising platelet-shaped magnetic or magnetizable pigment particles oriented according to a first magnetic pattern and a second motif, in the form of a cured second coating layer (210’) comprising platelet-shaped magnetic or magnetizable pigment particles oriented according to a second magnetic pattern, wherein said first and second motifs are at least partially intercalated and in register.
  • the OEL comprises the first motif, said first motif comprising at least n elements of a same first shape and the second motif, said second motif comprising m elements of a second shape, n and m being the same or different and being at least two, wherein both said first and second motifs are at least partially intercalated and wherein at least one of the elements of the first motif is at least partially adjacent to two elements of the second motif and/or at least one of the elements of the second motif is at least partially adjacent to two elements of the first motif.
  • FIG. 6 shows, for example, an OEL comprising the first and second motifs (210 and 21 O’), wherein the first motif comprises 24 elements in the form of lines and the second motif comprises 24 elements in the form of lines, and wherein at least a part of each of the 24 lines of the first motif is at least partially adjacent to two lines of the second motif and at least a part of each of the 24 lines of the second motif is at least partially adjacent to two lines of the first motif.
  • FIG. 7 shows, for example, an OEL comprising the first and second motifs (210 and 210’), wherein the first motif comprises more than 500 elements in the form of dots and the second motif comprises more than 500 elements in the form of dots and wherein at least a part of the dots of the first motif is at least partially adjacent to two dots of the second motif wherein at least a part of the dots of the second motif is at least partially adjacent to two dots of the first motif.
  • the OELs consist of the combination of the first and second motifs being at least partially intercalated with the first motif comprising a group of the at least n elements and the second motif comprising a group of the at least m elements, wherein at least a part of the said elements being at least partially adjacent to each other, wherein preferably the first and second motifs are complementary to each other.
  • first and second motifs due to the specific design of the first and second motifs as well as the n and m elements thereof described herein, said first and second motifs when combined to form the OELs are per se not perceptible to the naked eye at a distance due to the limited optical resolution of the eye, rather the first and second motifs form a composite motif which is perceived as a single image.
  • the OELs comprising the specific design of the first and second motifs as well as the n and m elements thereof are similar to halftone images prepared by methods known by one skilled in the art. Halftone printing processes are known, for example see: Handbook of Print Media, Helmut Kipphan, 2001 , pages 90-99.
  • the eye perceives from a normal and practical distance at least three colors when observing the OEL, i.e. the observer sees a smooth continuous variation of tone with variable colors (a smooth continuous variation of tone with optically variable colors (goniochromatic layers) for embodiments comprising optically variable motifs), that is, one perceives the color of the first motif per se, the color of the second motif per se and at least an intermediate color while using only a limited number of coating compositions, e.g. only two coating compositions having a different color.
  • the so-obtained OELs appear to the observer as a continuous image extending continuously along said OEL.
  • the so-obtained optical effect is particularly striking when the OEL comprises the first and second motifs being intercalated as well as the n and m elements thereof being at least partially adjacent as described herein, wherein said elements and motifs are produced by applying an amplitude modulation (the elements having different size) and/or a frequency modulation (different distances between the elements) and a hybrid modulation (that is simultaneous amplitude and frequency modulation (see Handbook of Print Media Helmut Kipphan, pages 91-98).
  • the first motif exhibits a variation of amplitude and/or frequency and the second motif exhibit a variation of amplitude and/or frequency.
  • the amplitude modulation and/or the frequency modulation of the elements are selected according to the desired resolution of the motifs and OELs. Since the initial patented process from Frederic Eugene Ives (see e.g. US 1 ,248,864), several techniques have been developed to optimize the parameters of the grid elements (see e.g. EP0342640B1 , US 4,758,886, EP0527655B1 , WO2020/221684A) and the halftone process is known in the art of printing. As an example shown in Fig.
  • the first motif in the form of the first coating layer (210) comprises 24 elements in the form of lines having different width (i.e. different amplitude from 0.7 mm to 0.35 mm) while being spaced apart by a same distance (i.e. a same frequency of 0.35 mm) and the second motif in the form of the second coating layer (210’) comprises 24 elements in the form of lines having a same width (i.e. a same amplitude of 0.35 mm) while being spaced apart by different distances (i.e. different frequency varying from 0.7 mm to 0.35 mm).
  • the first motif in the form of the first coating layer (210) and the second motif in the form of the second coating layer (210’) comprise each more than 500 elements in the form of dots having a same diameter (i.e. a constant amplitude of 0.35 mm) while being spaced apart by different distance (i.e. a different frequency) continuously decreasing from the top and bottom edges towards the center for the first motif, and continuously increasing from the top and bottom edges towards the center for the second motif, so that the dots of the first motif form an almost continuous layer in the center of the first coating layer, and so that the dots of the second motif form an almost continuous layer at the top and bottom edges of the second coating layer.
  • the first and second motifs are similar to Samba screens (see e.g.
  • the elements of the first motif and the elements of the second motif independently have a smallest dimension of less than about 2 mm (amplitude modulation), preferably less than about 1 mm and/or a distance between neighboring elements of the same motif being equal or smaller than 1 mm (frequency modulation).
  • the process of the invention advantageously allows to apply the first and second coating layer (210 and 210’) in register to produce OELs while a misregistration between the first and second coating layers (210 and 210’) would result in the boundaries of said layers becoming visible to the naked eye and hampering the formation of a third color, thus allowing an observer to conclude that the OEL is a fake or counterfeit one.
  • the n elements of the first motif and/or the m elements of the second motif preferably have a shape of a line, a dot or any geometrical shape such as discs and polygon.
  • the n elements of the first motif and/or the m elements of the second motif preferably have a shape of a line, wherein said line is a rectilinear or a curvilinear line.
  • the n elements of the first motif and/or the m elements of the second motif preferably have a shape of a dot, wherein said dot may be a round dot, a square dot, a chain dot or an elliptical dot.
  • the first (210) and second (210’) coating layers are applied on the same side of the substrate (220).
  • the first and second motifs i.e. the first and second cured coating layers 210 and 210’
  • the substrate (220) is at least partially transparent, and at least one element of the first motif is at least partially adjacent to two elements of the second motif and in register and/or at least one element of the second motif is at least partially adjacent to two elements of the first motif and in register.
  • adjacent is meant that at least one element of one motif and two elements of the other motif are contiguous (i.e. they share at least one region together and have a common border).
  • the at least one element of a motif and the two elements of the other motif have their projections on each side of the substrate (220) (see dotted line in Fig. 1 , embodiment B) being contiguous (i.e. they share at least one region together and have a common border).
  • the projection of the elements of the first and second motifs on each side of the substrate (220) are at least partially adjacent and in proper register.
  • the invention provides processes to produce the OELs of the invention on a substrate.
  • the substrate is preferably selected from the group consisting of papers or other fibrous materials (including woven and non-woven fibrous materials), such as cellulose, paper-containing materials, glasses, metals, ceramics, plastics and polymers, metalized plastics or polymers, at least partially opacified plastics or polymers, composite materials and mixtures or combinations of two or more thereof.
  • Typical paper, paper-like or other fibrous materials are made from a variety of fibers including without limitation abaca, cotton, linen, wood pulp, and blends thereof. As is well known to those skilled in the art, cotton and cotton/linen blends are preferred for banknotes, while wood pulp is commonly used in non-banknote security documents.
  • plastics and polymers include polyolefins such as polyethylene (PE) and polypropylene (PP) including biaxially oriented polypropylene (BOPP), polyamides, polyesters such as polyethylene terephthalate) (PET), poly(1 ,4-butylene terephthalate) (PBT), polyethylene 2,6-naphthoate) (PEN) and polyvinylchlorides (PVC). Spunbond olefin fibers such as those sold under the trademark Tyvek® may also be used as substrate.
  • Typical examples of metalized plastics or polymers include the plastic or polymer materials described hereabove having a metal disposed continuously or discontinuously on their surface.
  • Typical examples of metals include without limitation aluminum (Al), chromium (Cr), copper (Cu), gold (Au), silver (Ag), alloys thereof and combinations of two or more of the aforementioned metals.
  • the metallization of the plastic or polymer materials described hereabove may be done by an electrodeposition process, a high-vacuum coating process or by a sputtering process.
  • Opacified polymers have been developed with the aim of mimicking the appearance and some properties of conventional paper-based substrates for security document and consist of polymeric transparent substrates which are surface treated typically on one or on both of their sides with opacifying layers to form opacified polymer-based substrates.
  • Typical examples of composite materials include without limitation multilayer structures or laminates of paper and at least one plastic or polymer material such as those described hereabove as well as plastic and/or polymer fibers incorporated in a paper-like or fibrous material such as those described hereabove.
  • the substrate can comprise further additives that are known to the skilled person, such as fillers, sizing agents, Whiteners, processing aids, reinforcing or wet strengthening agents, etc.
  • said OEL may be produced on other type of substrates including finger and toe nails, artificial nails or other parts of an animal or human being.
  • the substrate (220) may be in the form of a web, sheet, thread reel, film reel, labels of the roll or label stocks, preferably a web or sheet.
  • the substrate may comprise printed, coated, or laser-marked or laser-perforated indicia, watermarks, security threads, fibers, planchettes, luminescent compounds, windows, foils, decals and combinations of two or more thereof.
  • the substrate may comprise one or more marker substances or taggants and/or machine readable substances.
  • the substrate (220) comprises a printed pattern, preferably an offset printed pattern, wherein the radiation-curable coating composition of steps a) and is applied at least partially on top of said printed pattern and the process of the invention comprises a step of printing an ink on the substrate (220), wherein said step occurs prior to step a).
  • a primer layer may be applied to the substrate (220) prior to step a). This may enhance the quality of the OEL or promote adhesion. Examples of such primer layers may be found in W02010/058026A2.
  • one or more protective layers may be applied on top of the OEL.
  • the one or more protective layers are typically made of protective varnishes. These may be transparent or slightly colored or tinted and may be more or less glossy.
  • Protective varnishes may be radiation-curable compositions, thermal drying compositions or any combination thereof.
  • the one or more protective layers are radiation-curable compositions, more preferably UV-Vis-curable compositions.
  • the protective layers are typically applied after the formation of the OEL.
  • the process of the invention may further comprise a step of embossing the OEL of the invention using, for example, an embossing dye or an intaglio printing plate as disclosed in W02012/025206A2 and WO2019/233624A1.
  • the OEL of the invention may be used in combination with holograms, microlenses and/or micromirrors as described in W02020/244805A1 , EP3254863A1 , US2008/0160226, US2005/0180020 and EP2284017A1 , said holograms, microlenses and/or micromirrors being applied at a position spaced apart from the OEL or least partially on top or below the OEL.
  • the invention further provides OELs produced by the process according to the invention.
  • the OEL of the invention may be provided directly on a substrate (220) on which it shall remain permanently (such as for banknote applications).
  • an OEL comprising the first and second motifs on the same side of the substrate may also be provided on a temporary substrate for production purposes, from which the OEL is subsequently removed. This may for example facilitate the production of the OEL, particularly while the binder material is still in its fluid state. Thereafter, after curing the radiation-curable compositions for the production of the OEL, the temporary substrate may be removed from the OEL.
  • an adhesive layer may be present.
  • An adhesive layer may be applied after the curing step of the second set of steps has been completed.
  • Such an article may be attached to all kinds of documents or other articles or items without printing or other processes involving machinery and rather high effort.
  • the substrate comprising the OEL of the invention may be in the form of a transfer foil, which can be applied to a document or to an article in a separate transfer step.
  • the substrate is provided with a release coating, on which the OEL is produced.
  • substrates comprising more than one, i.e. two, three, four, etc. OELs obtained by the process of the invention, each of said OELs independently comprising the first and second motifs in the form of the first and second coating layers.
  • articles, in particular security documents, decorative elements or objects comprising the OEL produced according to the invention.
  • the articles, in particular security documents, decorative elements or objects may comprise more than one (for example two, three, etc.) OELs produced according to the invention.
  • the OEL produced according to the invention may be used for decorative purposes as well as for protecting and authenticating a security document.
  • Typical examples of decorative elements or objects include without limitation luxury goods, cosmetic packaging, automotive parts, electronic/electrical appliances, furniture, fingernail and toenail articles.
  • Security documents include without limitation value documents and value commercial goods.
  • value documents include without limitation banknotes, deeds, tickets, checks, vouchers, fiscal stamps and tax labels, agreements and the like, identity documents such as passports, identity cards, visas, driving licenses, bank cards, credit cards, transactions cards, access documents or cards, entrance tickets, public transportation tickets or titles and the like, preferably banknotes, identity documents, right-conferring documents, driving licenses and credit cards.
  • value commercial good refers to packaging materials, in particular for cosmetic articles, nutraceutical articles, pharmaceutical articles, alcohols, tobacco articles, beverages or foodstuffs, electrical/electronic articles, fabrics or jewelry, i.e. articles that shall be protected against counterfeiting and/or illegal reproduction in order to warrant the content of the packaging like for instance genuine drugs.
  • packaging materials include without limitation labels, such as authentication brand labels, tamper evidence labels and seals. It is pointed out that the disclosed substrates, value documents and value commercial goods are given exclusively for exemplifying purposes, without restricting the scope of the invention.
  • the OEL may be produced onto an auxiliary substrate such as for example a security thread, security stripe, a foil, a decal, a window or a label and consequently transferred to a security document in a separate step.
  • an auxiliary substrate such as for example a security thread, security stripe, a foil, a decal, a window or a label
  • the magnetic field generating device (230) illustrated in Fig. 9 was used as the 1 st and 2 nd static magnetic field generating device (230 and 230’) to biaxially orient the platelet-shaped magnetic optically-variable pigment particles in the coating layers (210 and 210’) of the UV-curable screenprinting inks described in Table 1 (steps b1) and b’1)) to prepare the examples E1-E3.
  • the magnetic assembly (240) illustrated in Fig. 10 was used to orient platelet-shaped magnetic optically-variable pigment particles in the coating layers (210 and 210’) of the UV-curable screenprinting inks described in Table 1 , to produce the OELs shown in Fig. 12 (steps b2) and b’2)).
  • Fig. 5a a) depicts the screen used for the first coating layer (210) of Example E1
  • Fig. 5a b) depicts the screen used forthe second coating layer (210’) of Example E1
  • Fig. 5b a) depicts the screen used for the first coating layer (210) of Example E2
  • Fig. 5b b) depicts the screen used for the second coating layer (210’) of Example E2
  • Fig. 5c a) depicts the screen used for the first coating layer (210) of Example E3
  • Fig. 5c b) depicts the screen used for the second coating layer (210’) of Example E3.
  • the UV-curable screen-printing ink (A) was used for step a) and the UV-curable screen-printing ink (A’) was used for step a’) for each example E1-E3 (see Table 1).
  • a first UV-curable screen-printing ink (A) was applied [step a)] onto the substrate by hand screen-printing using a first 90T screen (290) so as to form the first coating layer (210) having a thickness of about 20
  • the substrate (220) carrying the coating layer (210) of the first UV-curable screen-printing ink was transported in front of the first static magnetic field generating device (230) (step b1)) and then disposed on a magnetic field generating device (240) (step b2).
  • the so-obtained magnetic orientation pattern of the platelet-shaped optically variable magnetic pigment particles was then, partially simultaneously with the orientation step b1), (i.e. while the substrate (220) carrying the coating layer (210) of the UV-curable screen-printing ink was still in the magnetic field of the magnetic field generating device (240), fixed by exposing for about 3 seconds to a UV-LED-lamp from Phoseon (Type FireFlex 50 x 75 mm, 395 nm, 8 W/cm 2 ) (step c).
  • a second UV-curable screen-printing ink (A’) was applied [step a’)] onto the substrate (220) in register with the coating layer (210) applied in step a), the application being carried out by hand screenprinting using a second 90T screen (290’) so as to form the second coating layer (210’) having a thickness of about 20
  • the substrate (220) carrying the coating layer (210’) of the second UV-curable screen-printing ink was transported in front of a second static magnetic field generating device (230’) [step b’1)] and then disposed on a magnetic field generating device (240’) (step b’2).
  • the so-obtained magnetic orientation pattern of the plateletshaped optically variable magnetic pigment particles was then, partially simultaneously with the orientation step b’1), [i.e. while the substrate (220) carrying the coating layer (210’) of the UV-curable screen-printing ink was still in the magnetic field of the magnetic field generating device (240’)], fixed by exposing for about 3 second to UV-curing using a second UV-LED-lamp from Phoseon (Type FireFlex 50 x 75 mm, 395 nm, 8 W/cm 2 ) (step c’).
  • the static magnetic-field-generating device (230) used to bi-axially orient the pigment particles according to the method of the invention was the magnetic assembly disclosed in WO2021/239607A, Fig. 3A, and depicted schematically in Fig. 9 of the present application.
  • the static magnetic-field-generating device (230) comprised a) a first set (S1) comprising a first bar dipole magnet (331 -a) and two second bar dipole magnets (332-a and 332-d), a second set (S2) comprising a first bar dipole magnet (331 -b) and two second bar dipole magnets (332-b and 332-e), a third set (S3) comprising a first bar dipole magnet (331 -c) and two second bar dipole magnets (332-c and 332-f),and b) a first pair (P1) of third bar dipole magnets (333-a and 333-b) and a second pair (P2) of third bar dipole magnets (333-c and 333-f).
  • the upmost surface of the first bar dipole magnet (331 -a, 331 -b and 331 -c) of the first, second and third sets (S1 , S2, S3), of the second bar dipole magnets (332-a to 332f) of the first, second and third sets (S1 , S2, S3) and of the third bar dipole magnets (333-a to 333-d) of the first and second pairs (P1 and P2) were flush with each other.
  • the third bar dipole magnet (333-a) was aligned with the second bar dipole magnet (332-a) of the first set (S1), with the second bar dipole magnet (332-b) of the second set (S2), with the third bar dipole magnet (333-c) and with the second bar dipole magnet (332-c) of the third set (S3) so as form a line.
  • the third bar dipole magnet (333-b) was aligned with the second bar dipole magnet (332-d) of the first set (S1), with the second bar dipole magnet (332-e) of the second set (S2), with the third bar dipole magnet (333-d) and with the second bar dipole magnet (332-f) of the third set (S3) so as form a line.
  • the third bar dipole magnets (333-a, 333-b, 333-c and 333-d) and the second bar dipole magnets (332-a to 332-f) were spaced apart by a third distance (d2) of 2 mm.
  • the first bar dipole magnet (331 -a) of the first set (S1) and the first bar dipole magnet (331 -b) of the second set (S2), and the first bar dipole magnet (331-c) of the third set (S3) were spaced apart by a distance (d3) of 24 mm.
  • the first bar dipole magnets (331 -a, 331 -b and 331-c) of the first, second and third sets (S1 , S2, S3) had the following dimensions: first length (L1) of 60 mm, first width (L2) of 40 mm and first thickness (L3) of 5 mm.
  • Each of the second bar dipole magnets (332-a to 332-f) of the first, second and third set (S1 , S2, S3) had the following dimensions: second length (L4) of 40 mm, second width (L5) of 10 mm and second thickness (L6) of 10 mm.
  • Each of the third bar dipole magnets (333-a to 333-d) of the first and second pairs (P1 , P2) had the following dimensions: third length (L7) of 20 mm, third width (L8) of 10 mm and third thickness (L9) of 10 mm.
  • the first bar dipole magnet (331 -a) of the first set (S1) and the second bar dipole magnets (332- a and 332-d) of the first set (S1) were aligned to form a column; and the first bar dipole magnet (331-b) of the second set (S2) and the second bar dipole magnets (332-b and 332-e) of the second set (S2) were aligned to form a column; and the first bar dipole magnet (331-c) of the third set (S3) and the second bar dipole magnets (332-c and 332-f) of the third set (S3) were aligned to form a column.
  • the first bar dipole magnets (331-a, 331-b and 331-c) and the two second bar dipole magnets (332-a and 332-d; 332-b and 332-e; and 332-c and 332-f, respectively) were spaced apart by a second distance (d1) of 2 mm.
  • the first bar dipole magnets (331-a, 331-b and 331-c) of the first, second and third sets (S1 , S2, S3) had their magnetic axis oriented to be substantially parallel to the plane of the substrate and substantially parallel to the substrate (220) surface, wherein the first bar dipole magnet (331-a) of the first set (S1) had its magnetic direction opposite to the magnetic direction of the first bar dipole magnet (331 -b) of the second set (S2), and the first bar dipole magnet (331-b) of the second set (S2) had its magnetic direction opposite to the magnetic direction of the first bar dipole magnet (331 -c) of the third set (S3).
  • the two second bar dipole magnets (332-a to 332-f) of the first, second and third set (S1 , S2, S3) had their magnetic axis oriented to be substantially perpendicular to the substrate (220) surface.
  • the South pole of the second bar dipole magnet (332-a) of the first set (S1), the South pole of the second bar dipole magnet (332-e) of the second set (S2) and the South pole of the second bar dipole magnet (332-c) of the third set (S3) pointed towards the plane of the substrate and towards the substrate (220).
  • the first bar dipole magnets (331-a, 331-b and 331 -c) of the first, second and third sets (S1 , S2, S3) and the second bar dipole magnets (332-a to 332-f) of the first, second and third sets (S1 , S2, S3) were made of NdFeB N42;
  • the third bar dipole magnets (333, 333-b and 333-c) of the first and second pairs (P1 , P2) were made of NdFeB N48.
  • All the magnets (331-a to 331 -c, 332-a to 332-f and 333-a to 333-d) were embedded in a non-magnetic supporting matrix (not shown) made of POM having the following dimensions: 200 mm x 120 mm x 12 mm.
  • the magnetic-field-generating device (240) used to prepare the OEL of examples E1-E3, is illustrated schematically in Fig. 10, and comprised a bar dipole magnet (441) and a holding case (460).
  • the bar dipole magnet (441) had a length (L1) of about 30 mm, a width (L2) of about 30 mm and a thickness (L3) of about 8.5 mm.
  • the North-South magnetic axis of the bar dipole magnet (441) was parallel to the substrate (220) surface and parallel to its width (L2).
  • the bar dipole magnet (440) was made of NdFeB BMnPi 80/48.
  • the holding case (460) was made of a hollow top part with a curved surface and a bottom lid.
  • the hollow top part had a length of about 40 mm, a width of about 40 mm, a thickness of about 15.1 mm and was made of PPS.
  • the bottom lid had a length of about 35 mm, a width of about 35 mm, a thickness of about 3 mm and was made of POM.
  • the curved surface was suitable to match the surface of a rotating magnetic cylinder of an industrial printing press.
  • the hollow top part was suitable for receiving the bar dipole magnet (441).
  • the distance (h) between the bar dipole magnet (441) surface and the surface of the substrate (220) was about 3.35 mm.
  • the OELs of Examples E1-E3 are shown when illuminated with ambient light (no particular angle of incidence) and observed at tilt angles of -45°, 0° and +45°, as shown in Fig. 11 , and when irradiated with UV light (365 nm) (last column of Fig. 12).
  • Example E1 the indicia “TEST” was hardly visible with the naked eye due to the use of the same optically variable pigments in both ink compositions A and A’, while the indicia “TEST” was clearly visible under UV-light due to the different luminescent compounds comprised in the ink compositions A and A’ as a result of the application in register of the ink compositions A and A’ in adjacent areas.
  • Example E2 only one optically variable effect layer (OEL) comprising a rolling bar effect printed in a green-to-blue color was visible. Under UV light, different luminescent colors were observed, a reddish luminescent color and a greenish luminescent color at each extremity of the printed layer, and mixed luminescent colors in the center of the printed layer as a result of the ink compositions A and A’ being printed with raster screen in register in intercalated positions.
  • OEL optically variable effect layer
  • Example E3 only one optically variable effect layer (OEL) comprising a rolling bar effect printed in a green-to-blue color was visible. Under UV light, reddish and greenish flower petals were clearly observable, as a result of the ink composition A’ being printed in register in full prints above parts of the ink layer printed with the ink composition A.
  • OEL optically variable effect layer

Landscapes

  • Printing Methods (AREA)

Abstract

L'invention concerne un procédé de production de nouvelles couches à effet optique (OEL).
PCT/EP2025/062055 2024-05-08 2025-05-02 Procédés de production de couches à effet optique Pending WO2025233239A1 (fr)

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Citations (77)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1248864A (en) 1916-02-04 1917-12-04 Frederic Eugene Ives Method of producing color photographs or films.
US2570856A (en) 1947-03-25 1951-10-09 Du Pont Process for obtaining pigmented films
US3676273A (en) 1970-07-30 1972-07-11 Du Pont Films containing superimposed curved configurations of magnetically orientated pigment
US3791864A (en) 1970-11-07 1974-02-12 Magnetfab Bonn Gmbh Method of ornamenting articles by means of magnetically oriented particles
US4758886A (en) 1986-07-24 1988-07-19 Minnesota Mining And Manufacturing Company Optimal color half-tone patterns for raster-scan images
US4838648A (en) 1988-05-03 1989-06-13 Optical Coating Laboratory, Inc. Thin film structure having magnetic and color shifting properties
US5364689A (en) 1992-02-21 1994-11-15 Hashimoto Forming Industry Co., Ltd. Painting with magnetically formed pattern and painted product with magnetically formed pattern
EP0342640B1 (fr) 1988-05-18 1996-02-07 Fuji Photo Film Co., Ltd. Procédé pour créer une trame de demi-teintes
EP0686675B1 (fr) 1994-06-01 1998-02-04 BASF Aktiengesellschaft Pigments métalliques brillants magnétisables à revêtements multiples
EP0527655B1 (fr) 1991-08-13 2000-11-02 Megadot Systems Limited Ecrans d'impression en demi-teints
WO2002073250A2 (fr) 2001-03-09 2002-09-19 Sicpa Holding S.A. Pigment ou dispositif d'interference en film mince magnetique et son procede de fabrication, encre d'impression ou composition de revetement, document de securite et utilisation d'un tel dispositif
WO2002090002A2 (fr) 2001-05-07 2002-11-14 Flex Products, Inc. Procedes de production d'articles revetus comportant des images dans lesquels on utilise des pigments magnetiques
WO2003000801A2 (fr) 2001-04-27 2003-01-03 Flex Products, Inc. Pigments et films magnetiques multicouches
US6565770B1 (en) 2000-11-17 2003-05-20 Flex Products, Inc. Color-shifting pigments and foils with luminescent coatings
WO2005002866A1 (fr) 2003-07-03 2005-01-13 Sicpa Holding S.A. Procede et moyen pour former un motif induit magnetiquement dans un revetement comprenant des particules magnetiques
US20050106367A1 (en) 2002-07-15 2005-05-19 Jds Uniphase Corporation Method and apparatus for orienting magnetic flakes
US20050180020A1 (en) 2003-11-21 2005-08-18 Steenblik Richard A. Micro-optic security and image presentation system
US7047883B2 (en) 2002-07-15 2006-05-23 Jds Uniphase Corporation Method and apparatus for orienting magnetic flakes
US7108742B2 (en) 2002-02-26 2006-09-19 Ciba Specialty Chemicals Corporation Ink compositions containing lanthanide complexes
US20070172261A1 (en) 2002-07-15 2007-07-26 Jds Uniphase Corporation Apparatus For Orienting Magnetic Flakes
EP1819525A1 (fr) * 2004-12-09 2007-08-22 Sicpa Holding S.A. Element de securite a aspect dependant de l'angle de vision
WO2007131833A1 (fr) 2006-05-12 2007-11-22 Sicpa Holding S.A. Composition de revêtement pour produire des images induites magnétiquement
WO2008033059A2 (fr) 2006-09-15 2008-03-20 Andrievsky Aleksandr Mikhailov Pigment luminescent résistant à l'eau et encre d'impression
US20080160226A1 (en) 2005-02-18 2008-07-03 Giesecke & Devriend Gmbh Security Element and Method for the Production Thereof
WO2008092522A1 (fr) 2007-01-31 2008-08-07 Henkel Ag & Co. Kgaa Colorants contenant des pigments luminescents qui peuvent être excités par la lumière visible
WO2009005733A2 (fr) 2007-06-28 2009-01-08 Honeywell International Inc. Complexes de métaux de terres rares excités dans la plage des longueurs d'onde de l'uv lointain
EP2157141A1 (fr) 2008-08-18 2010-02-24 JDS Uniphase Corporation Alignement bi-axial de plaquettes magnétiques
WO2010058026A2 (fr) 2008-11-24 2010-05-27 Sicpa Holding Sa Encre magnétiquement orientée sur une couche d'apprêt
DE102010009977A1 (de) * 2010-03-03 2011-09-08 Giesecke & Devrient Gmbh Sicherheitselement mit ausgerichteten Magnetpigmenten
US8025952B2 (en) 2002-09-13 2011-09-27 Jds Uniphase Corporation Printed magnetic ink overt security image
WO2012025206A2 (fr) 2010-08-25 2012-03-01 Giesecke & Devrient Gmbh Élément de sécurité à pigments magnétiques orientés
WO2012104098A1 (fr) 2011-02-04 2012-08-09 Sicpa Holding Sa Dispositif affichant un effet de mouvement visuel dynamique et son procédé de production
EP2402401B1 (fr) 2010-06-30 2013-11-13 JDS Uniphase Corporation Paillette de pigment multicouches magnétique et composition de revêtement
WO2013167425A1 (fr) 2012-05-07 2013-11-14 Sicpa Holding Sa Couche à effet optique
WO2014108303A1 (fr) 2013-01-09 2014-07-17 Sicpa Holding Sa Couches à effet optique présentant un effet optique dépendant de l'angle de vision, procédés et dispositifs pour leur production, articles comportant une couche à effet optique et leurs utilisations
CN102529326B (zh) 2011-12-02 2014-08-06 惠州市华阳光学技术有限公司 磁性颜料印刷品的磁定向装置、制造装置及制造方法
WO2014198905A2 (fr) 2013-06-14 2014-12-18 Sicpa Holding Sa Ensemble d'aimants permanents permettant de générer des lignes de champ concaves et procédé permettant de créer un revêtement à effet optique avec celui-ci (barre roulante inverse)
WO2015082344A1 (fr) 2013-12-04 2015-06-11 Sicpa Holding Sa Dispositifs de production de couches à effet d'optique
WO2015086257A1 (fr) 2013-12-13 2015-06-18 Sicpa Holding Sa Procédé de production de couches à effets
WO2015121028A1 (fr) * 2014-02-13 2015-08-20 Sicpa Holding Sa Fils et bandes de sécurité
WO2016015973A1 (fr) * 2014-07-29 2016-02-04 Sicpa Holding Sa Procédés permettant de durcir dans le champ des couches d'effet optique produites par des dispositifs de génération de champ magnétique générant des lignes de champ concaves
WO2016026896A1 (fr) 2014-08-22 2016-02-25 Sicpa Holding Sa Appareil et procédé de production de couches à effet optique
WO2017064052A1 (fr) 2015-10-15 2017-04-20 Sicpa Holding Sa Assemblages magnétiques et procédés de production de couches à effet optique comprenant des particules de pigment magnétiques ou magnétisables non sphériques orientées
WO2017080698A1 (fr) 2015-11-10 2017-05-18 Sicpa Holding Sa Appareils et procédés de production de couches à effet optique comprenant des particules de pigment magnétiques ou magnétisables non sphériques orientées
WO2017148789A1 (fr) 2016-02-29 2017-09-08 Sicpa Holding Sa Appareils et processus de production de couches à effet optique comprenant des particules de pigment magnétiques ou magnétisables non sphériques orientées
EP3254863A1 (fr) 2016-06-06 2017-12-13 Giesecke+Devrient Currency Technology GmbH Élément de sécurité pour un objet à protéger et procédé de fabrication d'un tel élément de sécurité
WO2018019594A1 (fr) 2016-07-29 2018-02-01 Sicpa Holding Sa Procédés de production de couches à effet
WO2018054819A1 (fr) 2016-09-22 2018-03-29 Sicpa Holding Sa Appareils et procédés de production de couches à effet optique comprenant des particules de pigment magnétiques ou magnétisables non sphériques orientées
EP3332982A1 (fr) * 2016-12-09 2018-06-13 Giesecke+Devrient Currency Technology GmbH Élément de sécurité pourvu de marques luminescentes
WO2018141547A1 (fr) 2017-01-31 2018-08-09 Sicpa Holding Sa Appareil et méthode de production de couches à effet optique
EP3224055B1 (fr) 2014-11-27 2018-08-22 Sicpa Holding SA Dispositifs et procédés d'orientation de particules pigmentaires magnétiques ou magnétisables en forme de plaquettes
WO2019038370A1 (fr) 2017-08-25 2019-02-28 Sicpa Holding Sa Ensembles et procédés de production de couches à effet optique comprenant des particules de pigment magnétiques ou magnétisables aplaties non sphériques orientées
WO2019038369A1 (fr) 2017-08-25 2019-02-28 Sicpa Holding Sa Ensembles et procédés de production de couches à effet optique comprenant des particules de pigment magnétiques ou magnétisables orientées non sphériques aplaties
WO2019038371A1 (fr) 2017-08-25 2019-02-28 Sicpa Holding Sa Ensembles et procédés de production de couches à effet optique comprenant des particules de pigment magnétiques ou magnétisables orientées non sphériques aplaties
WO2019103937A1 (fr) 2017-11-21 2019-05-31 Viavi Solutions Inc. Pigment asymétrique
WO2019215148A1 (fr) 2018-05-08 2019-11-14 Sicpa Holding Sa Ensembles et appareils magnétiques et procédés de production de couches à effet optique comprenant des particules de pigment magnétiques ou magnétisables non sphériques orientées
WO2019233624A1 (fr) 2018-06-05 2019-12-12 Giesecke+Devrient Currency Technology Gmbh Procédé de fabrication d'un document de valeur, document de valeur et dispositif d'impression
EP3587500A1 (fr) 2018-06-29 2020-01-01 Viavi Solution Inc Dispositifs optiques comportant une structure de couche asymétrique
EP3587501A1 (fr) 2018-06-29 2020-01-01 Viavi Solutions Inc. Dispositifs optiques comportant des molécules fonctionnelles
EP3587503A1 (fr) 2018-06-29 2020-01-01 Viavi Solutions Inc. Dispositifs optiques avec couche de modulateur azimutal
EP3587502A1 (fr) 2018-06-29 2020-01-01 Viavi Solutions Inc. Dispositifs optiques avec couche de réflecteur colorée
WO2020006286A1 (fr) 2018-06-29 2020-01-02 Viavi Solutions Inc. Composition comprenant des particules réfléchissantes
WO2020052862A1 (fr) * 2018-09-10 2020-03-19 Sicpa Holding Sa Procédés de production de couches à effet optique comprenant des particules de pigment magnétiques ou magnétisables non sphériques orientées
WO2020131700A1 (fr) 2018-12-17 2020-06-25 Viavi Solutions Inc. Article comprenant au moins une partie métallique
WO2020160993A1 (fr) 2019-02-08 2020-08-13 Sicpa Holding Sa Ensembles magnétiques et procédés de production de couches à effet optique comprenant des particules de pigment magnétiques ou magnétisables orientées non sphériques aplaties
WO2020193009A1 (fr) 2019-03-28 2020-10-01 Sicpa Holding Sa Ensembles magnétiques et procédés de production de couches à effet optique comprenant des particules de pigments magnétiques ou magnétisables non sphériques orientées
WO2020221684A1 (fr) 2019-04-30 2020-11-05 Agfa Nv Demi-teinte numérique à points en spirale
WO2020244805A1 (fr) 2019-06-06 2020-12-10 Giesecke+Devrient Currency Technology Gmbh Élément de sécurité optiquement variable à zone de surface réfléchissante multicolore
US20210038812A1 (en) 2016-12-22 2021-02-11 Medtronic Minimed, Inc. Insertion site monitoring methods and related infusion devices and systems
US20210101402A1 (en) 2019-10-08 2021-04-08 Viavi Solutions Inc. Security pigment and optical security element
WO2021083808A1 (fr) 2019-10-28 2021-05-06 Sicpa Holding Sa Ensembles magnétiques et procédés de production de couches à effet optique comprenant des particules de pigments magnétiques ou magnétisables non sphériques orientées
WO2021083809A1 (fr) 2019-10-28 2021-05-06 Sicpa Holding Sa Ensembles magnétiques et procédés de production de couches à effet optique comprenant des particules de pigments magnétiques ou magnétisables non sphériques orientées
WO2021239607A1 (fr) 2020-05-26 2021-12-02 Sicpa Holding Sa Ensembles magnétiques et méthodes de production de couches à effet optique comprenant des particules de pigment magnétiques ou magnétisables lamelliformes orientées
WO2021259527A1 (fr) 2020-06-23 2021-12-30 Sicpa Holding Sa Procédés de production de couches à effet optique comprenant des particules pigmentaires magnétiques ou magnétisables
WO2022004902A2 (fr) 2020-06-30 2022-01-06 전효화 Génération de signal pour la direction de rotation d'un moteur triphasé
WO2022049024A1 (fr) 2020-09-02 2022-03-10 Sicpa Holding Sa Documents ou articles de sécurité comportant des couches à effet optique comprenant des particules de pigments magnétiques ou magnétisables et procédés de production desdites couches à effet optique
US20220282094A1 (en) 2021-03-04 2022-09-08 Viavi Solutions Inc. Pigment including an intermetallic compound

Patent Citations (81)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1248864A (en) 1916-02-04 1917-12-04 Frederic Eugene Ives Method of producing color photographs or films.
US2570856A (en) 1947-03-25 1951-10-09 Du Pont Process for obtaining pigmented films
US3676273A (en) 1970-07-30 1972-07-11 Du Pont Films containing superimposed curved configurations of magnetically orientated pigment
US3791864A (en) 1970-11-07 1974-02-12 Magnetfab Bonn Gmbh Method of ornamenting articles by means of magnetically oriented particles
US4758886A (en) 1986-07-24 1988-07-19 Minnesota Mining And Manufacturing Company Optimal color half-tone patterns for raster-scan images
US4838648A (en) 1988-05-03 1989-06-13 Optical Coating Laboratory, Inc. Thin film structure having magnetic and color shifting properties
EP0342640B1 (fr) 1988-05-18 1996-02-07 Fuji Photo Film Co., Ltd. Procédé pour créer une trame de demi-teintes
EP0527655B1 (fr) 1991-08-13 2000-11-02 Megadot Systems Limited Ecrans d'impression en demi-teints
US5630877A (en) 1992-02-21 1997-05-20 Hashimoto Forming Industry Co., Ltd. Painting with magnetically formed pattern and painted product with magnetically formed pattern
US5364689A (en) 1992-02-21 1994-11-15 Hashimoto Forming Industry Co., Ltd. Painting with magnetically formed pattern and painted product with magnetically formed pattern
EP0686675B1 (fr) 1994-06-01 1998-02-04 BASF Aktiengesellschaft Pigments métalliques brillants magnétisables à revêtements multiples
US6565770B1 (en) 2000-11-17 2003-05-20 Flex Products, Inc. Color-shifting pigments and foils with luminescent coatings
WO2002073250A2 (fr) 2001-03-09 2002-09-19 Sicpa Holding S.A. Pigment ou dispositif d'interference en film mince magnetique et son procede de fabrication, encre d'impression ou composition de revetement, document de securite et utilisation d'un tel dispositif
WO2003000801A2 (fr) 2001-04-27 2003-01-03 Flex Products, Inc. Pigments et films magnetiques multicouches
US6838166B2 (en) 2001-04-27 2005-01-04 Flex Products, Inc. Multi-layered magnetic pigments and foils
WO2002090002A2 (fr) 2001-05-07 2002-11-14 Flex Products, Inc. Procedes de production d'articles revetus comportant des images dans lesquels on utilise des pigments magnetiques
US7108742B2 (en) 2002-02-26 2006-09-19 Ciba Specialty Chemicals Corporation Ink compositions containing lanthanide complexes
US20050106367A1 (en) 2002-07-15 2005-05-19 Jds Uniphase Corporation Method and apparatus for orienting magnetic flakes
US7047883B2 (en) 2002-07-15 2006-05-23 Jds Uniphase Corporation Method and apparatus for orienting magnetic flakes
US20070172261A1 (en) 2002-07-15 2007-07-26 Jds Uniphase Corporation Apparatus For Orienting Magnetic Flakes
US8025952B2 (en) 2002-09-13 2011-09-27 Jds Uniphase Corporation Printed magnetic ink overt security image
WO2005002866A1 (fr) 2003-07-03 2005-01-13 Sicpa Holding S.A. Procede et moyen pour former un motif induit magnetiquement dans un revetement comprenant des particules magnetiques
US20050180020A1 (en) 2003-11-21 2005-08-18 Steenblik Richard A. Micro-optic security and image presentation system
EP2284017A2 (fr) 2003-11-21 2011-02-16 Visual Physics, LLC Systeme de securite micro-optique et de presentation d'image
EP1819525A1 (fr) * 2004-12-09 2007-08-22 Sicpa Holding S.A. Element de securite a aspect dependant de l'angle de vision
EP1819525B1 (fr) 2004-12-09 2010-03-17 Sicpa Holding S.A. Element de securite a aspect dependant de l'angle de vision
US20080160226A1 (en) 2005-02-18 2008-07-03 Giesecke & Devriend Gmbh Security Element and Method for the Production Thereof
WO2007131833A1 (fr) 2006-05-12 2007-11-22 Sicpa Holding S.A. Composition de revêtement pour produire des images induites magnétiquement
WO2008033059A2 (fr) 2006-09-15 2008-03-20 Andrievsky Aleksandr Mikhailov Pigment luminescent résistant à l'eau et encre d'impression
WO2008092522A1 (fr) 2007-01-31 2008-08-07 Henkel Ag & Co. Kgaa Colorants contenant des pigments luminescents qui peuvent être excités par la lumière visible
WO2009005733A2 (fr) 2007-06-28 2009-01-08 Honeywell International Inc. Complexes de métaux de terres rares excités dans la plage des longueurs d'onde de l'uv lointain
EP2157141A1 (fr) 2008-08-18 2010-02-24 JDS Uniphase Corporation Alignement bi-axial de plaquettes magnétiques
WO2010058026A2 (fr) 2008-11-24 2010-05-27 Sicpa Holding Sa Encre magnétiquement orientée sur une couche d'apprêt
DE102010009977A1 (de) * 2010-03-03 2011-09-08 Giesecke & Devrient Gmbh Sicherheitselement mit ausgerichteten Magnetpigmenten
EP2402401B1 (fr) 2010-06-30 2013-11-13 JDS Uniphase Corporation Paillette de pigment multicouches magnétique et composition de revêtement
WO2012025206A2 (fr) 2010-08-25 2012-03-01 Giesecke & Devrient Gmbh Élément de sécurité à pigments magnétiques orientés
WO2012104098A1 (fr) 2011-02-04 2012-08-09 Sicpa Holding Sa Dispositif affichant un effet de mouvement visuel dynamique et son procédé de production
CN102529326B (zh) 2011-12-02 2014-08-06 惠州市华阳光学技术有限公司 磁性颜料印刷品的磁定向装置、制造装置及制造方法
WO2013167425A1 (fr) 2012-05-07 2013-11-14 Sicpa Holding Sa Couche à effet optique
WO2014108303A1 (fr) 2013-01-09 2014-07-17 Sicpa Holding Sa Couches à effet optique présentant un effet optique dépendant de l'angle de vision, procédés et dispositifs pour leur production, articles comportant une couche à effet optique et leurs utilisations
WO2014198905A2 (fr) 2013-06-14 2014-12-18 Sicpa Holding Sa Ensemble d'aimants permanents permettant de générer des lignes de champ concaves et procédé permettant de créer un revêtement à effet optique avec celui-ci (barre roulante inverse)
WO2015082344A1 (fr) 2013-12-04 2015-06-11 Sicpa Holding Sa Dispositifs de production de couches à effet d'optique
WO2015086257A1 (fr) 2013-12-13 2015-06-18 Sicpa Holding Sa Procédé de production de couches à effets
WO2015121028A1 (fr) * 2014-02-13 2015-08-20 Sicpa Holding Sa Fils et bandes de sécurité
WO2016015973A1 (fr) * 2014-07-29 2016-02-04 Sicpa Holding Sa Procédés permettant de durcir dans le champ des couches d'effet optique produites par des dispositifs de génération de champ magnétique générant des lignes de champ concaves
WO2016026896A1 (fr) 2014-08-22 2016-02-25 Sicpa Holding Sa Appareil et procédé de production de couches à effet optique
EP3224055B1 (fr) 2014-11-27 2018-08-22 Sicpa Holding SA Dispositifs et procédés d'orientation de particules pigmentaires magnétiques ou magnétisables en forme de plaquettes
WO2017064052A1 (fr) 2015-10-15 2017-04-20 Sicpa Holding Sa Assemblages magnétiques et procédés de production de couches à effet optique comprenant des particules de pigment magnétiques ou magnétisables non sphériques orientées
WO2017080698A1 (fr) 2015-11-10 2017-05-18 Sicpa Holding Sa Appareils et procédés de production de couches à effet optique comprenant des particules de pigment magnétiques ou magnétisables non sphériques orientées
WO2017148789A1 (fr) 2016-02-29 2017-09-08 Sicpa Holding Sa Appareils et processus de production de couches à effet optique comprenant des particules de pigment magnétiques ou magnétisables non sphériques orientées
EP3254863A1 (fr) 2016-06-06 2017-12-13 Giesecke+Devrient Currency Technology GmbH Élément de sécurité pour un objet à protéger et procédé de fabrication d'un tel élément de sécurité
WO2018019594A1 (fr) 2016-07-29 2018-02-01 Sicpa Holding Sa Procédés de production de couches à effet
WO2018054819A1 (fr) 2016-09-22 2018-03-29 Sicpa Holding Sa Appareils et procédés de production de couches à effet optique comprenant des particules de pigment magnétiques ou magnétisables non sphériques orientées
EP3332982A1 (fr) * 2016-12-09 2018-06-13 Giesecke+Devrient Currency Technology GmbH Élément de sécurité pourvu de marques luminescentes
US20210038812A1 (en) 2016-12-22 2021-02-11 Medtronic Minimed, Inc. Insertion site monitoring methods and related infusion devices and systems
WO2018141547A1 (fr) 2017-01-31 2018-08-09 Sicpa Holding Sa Appareil et méthode de production de couches à effet optique
WO2019038370A1 (fr) 2017-08-25 2019-02-28 Sicpa Holding Sa Ensembles et procédés de production de couches à effet optique comprenant des particules de pigment magnétiques ou magnétisables aplaties non sphériques orientées
WO2019038369A1 (fr) 2017-08-25 2019-02-28 Sicpa Holding Sa Ensembles et procédés de production de couches à effet optique comprenant des particules de pigment magnétiques ou magnétisables orientées non sphériques aplaties
WO2019038371A1 (fr) 2017-08-25 2019-02-28 Sicpa Holding Sa Ensembles et procédés de production de couches à effet optique comprenant des particules de pigment magnétiques ou magnétisables orientées non sphériques aplaties
WO2019103937A1 (fr) 2017-11-21 2019-05-31 Viavi Solutions Inc. Pigment asymétrique
WO2019215148A1 (fr) 2018-05-08 2019-11-14 Sicpa Holding Sa Ensembles et appareils magnétiques et procédés de production de couches à effet optique comprenant des particules de pigment magnétiques ou magnétisables non sphériques orientées
WO2019233624A1 (fr) 2018-06-05 2019-12-12 Giesecke+Devrient Currency Technology Gmbh Procédé de fabrication d'un document de valeur, document de valeur et dispositif d'impression
EP3587500A1 (fr) 2018-06-29 2020-01-01 Viavi Solution Inc Dispositifs optiques comportant une structure de couche asymétrique
EP3587501A1 (fr) 2018-06-29 2020-01-01 Viavi Solutions Inc. Dispositifs optiques comportant des molécules fonctionnelles
EP3587502A1 (fr) 2018-06-29 2020-01-01 Viavi Solutions Inc. Dispositifs optiques avec couche de réflecteur colorée
WO2020006286A1 (fr) 2018-06-29 2020-01-02 Viavi Solutions Inc. Composition comprenant des particules réfléchissantes
EP3587503A1 (fr) 2018-06-29 2020-01-01 Viavi Solutions Inc. Dispositifs optiques avec couche de modulateur azimutal
WO2020052862A1 (fr) * 2018-09-10 2020-03-19 Sicpa Holding Sa Procédés de production de couches à effet optique comprenant des particules de pigment magnétiques ou magnétisables non sphériques orientées
WO2020131700A1 (fr) 2018-12-17 2020-06-25 Viavi Solutions Inc. Article comprenant au moins une partie métallique
WO2020160993A1 (fr) 2019-02-08 2020-08-13 Sicpa Holding Sa Ensembles magnétiques et procédés de production de couches à effet optique comprenant des particules de pigment magnétiques ou magnétisables orientées non sphériques aplaties
WO2020193009A1 (fr) 2019-03-28 2020-10-01 Sicpa Holding Sa Ensembles magnétiques et procédés de production de couches à effet optique comprenant des particules de pigments magnétiques ou magnétisables non sphériques orientées
WO2020221684A1 (fr) 2019-04-30 2020-11-05 Agfa Nv Demi-teinte numérique à points en spirale
WO2020244805A1 (fr) 2019-06-06 2020-12-10 Giesecke+Devrient Currency Technology Gmbh Élément de sécurité optiquement variable à zone de surface réfléchissante multicolore
US20210101402A1 (en) 2019-10-08 2021-04-08 Viavi Solutions Inc. Security pigment and optical security element
WO2021083808A1 (fr) 2019-10-28 2021-05-06 Sicpa Holding Sa Ensembles magnétiques et procédés de production de couches à effet optique comprenant des particules de pigments magnétiques ou magnétisables non sphériques orientées
WO2021083809A1 (fr) 2019-10-28 2021-05-06 Sicpa Holding Sa Ensembles magnétiques et procédés de production de couches à effet optique comprenant des particules de pigments magnétiques ou magnétisables non sphériques orientées
WO2021239607A1 (fr) 2020-05-26 2021-12-02 Sicpa Holding Sa Ensembles magnétiques et méthodes de production de couches à effet optique comprenant des particules de pigment magnétiques ou magnétisables lamelliformes orientées
WO2021259527A1 (fr) 2020-06-23 2021-12-30 Sicpa Holding Sa Procédés de production de couches à effet optique comprenant des particules pigmentaires magnétiques ou magnétisables
WO2022004902A2 (fr) 2020-06-30 2022-01-06 전효화 Génération de signal pour la direction de rotation d'un moteur triphasé
WO2022049024A1 (fr) 2020-09-02 2022-03-10 Sicpa Holding Sa Documents ou articles de sécurité comportant des couches à effet optique comprenant des particules de pigments magnétiques ou magnétisables et procédés de production desdites couches à effet optique
US20220282094A1 (en) 2021-03-04 2022-09-08 Viavi Solutions Inc. Pigment including an intermetallic compound

Non-Patent Citations (9)

* Cited by examiner, † Cited by third party
Title
"Ferromagnetic Materials", vol. 2, 1999, ELSEVIER, article "Soft Magnetic Metallic Materials", pages: 55 - 188,189-241
"Handbook of Condensed Matter and Materials Data", 2005, SPRINGER, article "Soft Magnetic Materials", pages: 758 - 793,811-813
"Handbook of modern Ferromagnetic Materials", 2002, KLUWER ACADEMIC PUBLISHERS, article "High-permeability Highfrequency Metal Strip", pages: 155 - 182
"Handbook of Print Media Helmut Kipphan", pages: 91 - 98
"Smithells Metals Reference Book", 1992, BUTTERWORTH-HEINEMANN LTD, article "Magnetically Soft Materials", pages: 9 - 16
C. MOOSBRUGGER: "Electric and Magnetic Properties of Metals", 2000, ASM INTERNATIONAL, article "Magnetically Soft Materials", pages: 196 - 209
HELMUT KIPPHAN: "Handbook of Print Media", 2001, pages: 96 - 99
NICOLA A. SPALDIN: "Magnetic Materials, Fundamentals and Applications", 2011, CAMBRIDGE UNIVERSITY PRESS, pages: 16 - 17
Z.Q. ZHUD. HOWE: "Halbach permanent magnet machines and applications: a review", IEE. PROC. ELECTRIC POWER APPL., vol. 148, 2001, pages 299 - 308, XP006016918, DOI: 10.1049/ip-epa:20010479

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