Method and means for magnetically transferring indicia to a coating composition applied on a substrate

Abstract

The invention concerns a device for magnetically transferring indicia, such as a design or an image, to a wet coating layer applied on a substrate, such as a sheet or a web, wherein the said coating layer comprises at least one type of magnetic or magnetizable particles; said device comprising a) at least one magnetized permanent-magnetic plate ( 2 ) carrying relief, engravings or cut-outs, mounted such that its relief surface remains accessible, b) at least one additional magnet ( 3 ), disposed below said at least one permanent-magnetic plate, facing the surface of the magnetic plate which is opposite to the relief, engraving or cut-out, and c) a holder ( 1 ), which has the mechanical function to hold the pieces together in fixed positions. A method for producing the device, the use of the device, and magnetically induced designs obtained with the device, which are useful for protecting currency, value—and identity documents, are disclosed as well.

What is claimed is: 
     
         1 . A coated substrate comprising at least one coating layer on a surface, said coating layer comprising magnetic or magnetizable pigment flakes, wherein indicia are embodied in said coating layer through a selective orientation of said magnetic or magnetizable pigment flakes, the selective orientation being caused by
 exposing the coating layer in a wet stage to the magnetic field of a device comprising:
 at least one permanent-magnetic plate having a first magnetic field, wherein at least one surface of the permanent-magnetic plate comprises a relief, engraving or cut-out representing said indicia; and 
 at least one additional magnet having a second magnetic field, wherein said at least one additional magnet is fixedly positioned underneath said at least one permanent-magnetic plate, so as to produce overlap of the first and second magnetic fields, 
 wherein said at least one permanent-magnetic plate and said at least one additional magnet are mounted in positions which hold them against the inherent magnetic forces working between them; and 
   subsequently hardening or curing the coating layer.   
     
     
         2 . The coated substrate according to  claim 1 , wherein the magnetic or magnetizable pigment flakes in at least one area of the coating layer which does not embody indicia are oriented at an angle of less than 45° to the surface of said substrate. 
     
     
         3 . The coated substrate according to  claim 1 , wherein said substrate is a security element for the protection of bank notes, value documents, identity documents, cards, tax stamps, labels, windows, foils, or threads. 
     
     
         4 . The coated substrate according to  claim 1 , wherein said substrate is a security document such as a bank note, a value document, an identity document, a card, a tax stamp, a label, or a product. 
     
     
         5 . The coated substrate according to  claim 1 , wherein more than 50% of the magnetic or magnetizable pigment flakes are oriented at an angle of less than 45° to the surface of said substrate. 
     
     
         6 . A method for transferring indicia to a substrate, comprising:
 (a) applying a layer of a coating composition to at least a part of a first surface of said substrate, the coating composition comprising magnetic or magnetizable pigment flakes;   (b) exposing the coated substrate, whilst the coating is wet, to the magnetic field of a device, the device comprising at least one magnetized magnetic plate having a first magnetic field and having surface relief, engravings or cut-outs on a surface thereof representing said indicia, and at least one additional magnet having a second magnetic field, wherein said additional magnet is fixedly positioned adjacent to said magnetic plate, so as to produce substantial overlap of their magnetic fields;   (c) hardening or curing the coating composition, thereby irreversibly fixing the orientation of the oriented magnetic or magnetizable pigment flakes.   
     
     
         7 . The method according to  claim 6 , wherein said magnetic plate and said additional magnet are arranged so as to produce a magnetic field having an angle of less than 45° to the plane of said relief surface in at least one surface area not carrying a relief, engraving or cut-out. 
     
     
         8 . The method according to  claim 6 , wherein the exposing (b) further comprises:
 bringing said coating composition into close proximity with said relief surface of said magnetic plate; or   bringing a second surface of the substrate, opposite to said first surface carrying said coating composition, into contact with said relief surface of said magnetic plate.   
     
     
         9 . The method according to  claim 6 , further comprising mounting the device on a rotatable cylinder on a printing machine. 
     
     
         10 . The method according to  claim 6 , wherein the substrate is a sheet or web. 
     
     
         11 . A method for transferring indicia to a substrate comprising:
 (a) applying a layer of a coating composition to at least a part of a first surface of said substrate, the coating composition comprising magnetic or magnetizable pigment flakes;   (b) exposing the coated substrate, whilst the coating is wet, to the magnetic field of a device so as to orient the magnetic or magnetizable pigment flakes, said device comprising:
 at least one permanent-magnetic plate having a first magnetic field, wherein at least one surface of the permanent-magnetic plate represents the indicia to be transferred by comprising a relief, engraving or cut-out; and 
 at least one additional magnet having a second magnetic field, wherein said at least one additional magnet is fixedly positioned underneath said at least one permanent-magnetic plate, so as to produce overlap of the first and second magnetic fields, 
 wherein said at least one permanent-magnetic plate and said at least one additional magnet are mounted in positions which hold them against the inherent magnetic forces working between them; and 
   (c) hardening or curing the wet layer of the coating composition, thereby irreversibly fixing the orientation of the oriented magnetic or magnetizable pigment flakes.   
     
     
         12 . The method according to  claim 11 , wherein the at least one surface of the permanent-magnetic plate comprising the relief, engraving or cut-out further comprises at least one plane surface area having no relief, engraving or cut-out, and said at least one permanent-magnetic plate and said at least one additional magnet are arranged so as to produce a magnetic field having an angle of less than 45° to the at least one plane surface area of the permanent-magnetic plate having no relief, engraving or cut-out. 
     
     
         13 . The method according to  claim 11 , wherein exposing the coated substrate in (b) further comprises:
 bringing said coating composition into close proximity with the at least one surface of the permanent-magnetic plate; or   bringing a second surface of the substrate, opposite to said first surface carrying said coating composition, into contact with the at least one surface of the permanent-magnetic plate.   
     
     
         14 . The method according to  claim 11 , further comprising mounting the device on a rotatable cylinder on a printing machine. 
     
     
         15 . The method according to  claim 11 , wherein the substrate is a sheet or web.