Securing the Authenticity of Value Documents By Means of Characteristic Substances

Abstract

The invention relates to a feature substance for securing the authenticity of documents of value, having at least one luminescent substance in particle form and nanoparticles enveloping the surfaces of the luminescent substance particles at least partially, wherein the properties of the feature substance result from the interaction of the properties of the luminescent substance and of the nanoparticles. The invention furthermore relates to a method for producing the feature substance, a method for securing the authenticity of a security element or document of value using a feature substance, as well as security elements and documents of value with authenticity features on the basis of the feature substance.

1 . A feature substance for securing the authenticity of documents of value, comprising at least one luminescent substance in particle form excitable by radiation in at least one of the infrared visible and ultraviolet spectrum to emit luminescence, comprising nanoparticles enveloping the surfaces of the luminescent substance particles at least partially, wherein properties of the feature substance result from the interaction of the luminescence emission properties of the luminescent substance and properties of the nanoparticles. 
   
   
       2 . The feature substance according to  claim 1 , wherein the luminescent substance emits in at least one of the infrared, visible and ultraviolet spectrum. 
   
   
       3 . The feature substance according to  claim 1 , wherein the luminescent substance particles are enveloped substantially completely by substantially a monolayer of nanoparticles. 
   
   
       4 . A method according to  claim 1 , wherein the luminescent substance is selected from luminescent substances on the basis of host lattices doped with at least one rare earth metal. 
   
   
       5 . The feature substance according to  claim 1 , wherein the luminescent substance is selected from the mineral-phosphorus compounds. 
   
   
       6 . The feature substance according to  claim 1 , wherein the luminescent substance is selected from organic luminescent substances. 
   
   
       7 . The feature substance according to  claim 1 , wherein the luminescent substance is present in the form of particles with an average particle size in the range of 1 to 100 μm. 
   
   
       8 . The feature substance according to  claim 1 , wherein the nanoparticles are selected from the group consisting of magnetic materials, magnetizable materials, electrically conductive materials, semiconductor materials and mixtures thereof. 
   
   
       9 . The feature substance according to  claim 1 , wherein the nanoparticles are selected from the group consisting of carbon nano tubes, nano α-iron, nano Fe 3 O 4 , nano NiFe 2 O 4  and mixtures thereof. 
   
   
       10 . The feature substance according to  claim 1 , wherein the nanoparticles have an average particle size in the range of 1 to 1000 nm. 
   
   
       11 . The feature substance according to  claim 1 , wherein the weight ratio of luminescent substance particles to nanoparticles is in the range of 10:1 to 1:10. 
   
   
       12 . The feature substance according to  claim 1 , including luminescent substance particles that are not enveloped by either or both nanoparticles, and free nanoparticles. 
   
   
       13 . The feature substance according to  claim 1 , including either or both at least two different luminescent substances and at least two different types of nanoparticles. 
   
   
       14 . A method for producing a feature substance as defined in  claim 1 , comprising adding at least one luminescent substance in particle form and at least one substance in the form of a nano powder to a dispersant and stirring the mixture for such a time until a dispersion is obtained. 
   
   
       15 . The method according to  claim 14 , wherein the dispersion is filtered to separate the feature substance. 
   
   
       16 . The method according to  claim 15 , wherein the separated feature substance is dried. 
   
   
       17 . The method according to  claim 14 , wherein as dispersant water is used. 
   
   
       18 . The method according to  claim 14 , wherein the feature substance is mixed with either or both at least one further feature substance and/or and at least one further type of nanoparticles. 
   
   
       19 . A method for securing the authenticity of a security element or document of value, comprising:
 applying a feature substance as defined in  claim 1 , on at least partial areas of at least one surface of the security element or document of value, or integrating a feature substance as defined in  claim 1 , in at least one partial area of the volume of the document of value or security element.   
   
   
       20 . The method according to  claim 19 , wherein the security element or document of value is subjected to electrical or magnetic fields during the application or integration of the feature substance in such a fashion that an orientation and, if desired, a migration of the feature substance particles within the electrical or magnetic field takes place. 
   
   
       21 . The method according to  claim 20 , the migration leads to a defined distribution of the feature substance particles that is machine-verifiable or visually verifiable. 
   
   
       22 . The method according to  claim 21 , wherein the defined distribution forms a code. 
   
   
       23 . A document of value or security element comprising at least one carrier material and, on or within the carrier material, at least one authenticity feature based on a feature substance, wherein the feature substance is a substance as defined in  claim 1 . 
   
   
       24 . The document of value or security element according to  claim 23 , wherein the carrier material comprises paper or plastic. 
   
   
       25 . The document of value or security element according to  claim 23 , wherein the feature substance is provided in the volume of the carrier material. 
   
   
       26 . The document of value or security element according to  claim 23 , wherein the feature substance is present in a layer applied on at least partial areas of a surface of the carrier material. 
   
   
       27 . The document of value or security element according to  claim 23 , wherein the feature substance is present in a printing ink applied on a surface of the document of value or security element. 
   
   
       28 . The document of value or security element according to  claim 23 , wherein the feature substance shows a defined distribution which is visually verifiable or machine-verifiable. 
   
   
       29 . The document of value or security element according to  claim 28 , wherein the defined distribution forms a code. 
   
   
       30 . The security element according to  claim 23 , having a configuration of at least one of a security thread, mottling fiber, planchet or label. 
   
   
       31 . The document of value according to  claim 23 , including a security element according to  claim 23 .