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Method for protecting against forgery sheet-like printed documents

  • US 5,789,019 A
  • Filed: 07/17/1995
  • Issued: 08/04/1998
  • Est. Priority Date: 07/21/1994
  • Status: Expired due to Fees
First Claim
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1. A method for protecting printed papers and documents against forgery, comprising a step of applying on a document, during a printing thereof, a protective breakable microcapsule layer, said layer including a plurality of breakable microcapsules containing a chemical product adapted to leave an indelible mark on a surface portion of said document as said document is subjected to a tampering force causing said breakable microcapsules to be broken, said breakable microcapsules having a melting temperature of 85°

  • C.-90°

    C. and being dispersed in a not fully embedded condition in a waxy material, said waxy material, with said breakable microcapsules dispersed therein, being applied on said surface portion of said document at a temperature less than 100°

    C. such that said microcapsules are not damaged thereby, said breakable microcapsules being applied in an amount from 4 g/m2 to 7 g/m2 on said document, said method further comprising a step of applying fluorescent inks on at least a surface of said document, such that an attempt to remove said waxy material by means of solvent will dissolve the printing ink used in said printing.

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