Security paper

• US 4,136,229 A
• Filed: 10/25/1977
• Issued: 01/23/1979
• Est. Priority Date: 05/25/1976
• Status: Expired due to Term

• Current Assignee: ARJO Wiggins Limited (Sequana SA)
• Original Assignee: Societe Anonyme DITE Arjomari-Prioux
• Inventors: Bartoli, Giampaolo, Godet, Jean-Yves
• Primary Examiner(s): Ansher, Harold
• Application Number:
  US05/845,112
• Time in Patent Office: 455 Days
• Field of Search: 427/7, 427/157, 427/158, 106/148, 8/1 B, 8/54.2, 428/913, 428/916, 428/537, 428/411, 162/140
• US Class Current: 162/140
• CPC Class Codes: B41M 3/142 using chemical colour-formers or chemical reactions, e.g. leuco-dye/acid, photochromes
• CPC Class Codes: B41M 3/144 using fluorescent, luminescent or iridescent effects
• CPC Class Codes: B42D 25/29 Securities; Bank notes
• CPC Class Codes: C09K 11/06 containing organic luminescent materials
• CPC Class Codes: D21H 21/46 Elements suited for chemical verification or impeding chemical tampering, e.g. by use of eradicators
• CPC Class Codes: Y10S 428/913 Material designed to be responsive to temperature, light, moisture
• CPC Class Codes: Y10S 428/916 Fraud or tamper detecting

Abstract

Security paper which immediately reveals an attempt to alter handwriting thereon by the use of an alkaline ink remover and which is characterized by the incorporation therein of a pyrenesulphonic acid or a metal salt thereof, particularly an alkali metal or alkaline earth metal salt.

Security paper incorporating such an acid or salt exhibits a fluorescent coloration when contacted with an alkaline ink remover.

Claims

1. Security paper having incorporated therein from 0.02 to 1 g per square meter of at least one fluorescent dyestuff selected from the group consisting of a pyrenesulfonic acid and a metal salt thereof, said dyestuff not normally affecting the coloration of said paper but exhibiting a fluorescent coloration visible in daylight and in conventional lighting when said paper is contacted by an alkaline reagent.

2. Security paper as set forth in claim 1, wherein said dyestuff is a salt selected from the group consisting of alkali metal and alkaline earth metal salts.

3. Security paper as set forth in claim 1, wherein said dyestuff is selected from the group consisting of pyrenesulfonic acids of the formula:

##STR3## wherein X₁, X₂, X₃ and X₄ are individually selected from the group consisting of H, SO₃ H and an electron donor group, provided that at least one of X₁, X₂, X₃ and X₄ is an SO₃ H group, and X₅ is selected from the group consisting of H and C₁ -C₄ alkyl groups substituted on any substitutable carbon atom of the pyrene ring system not already occupied by another substituent, and alkali metal and alkaline earth metal salts of said acids.

4. Security paper as set forth in claim 3, wherein said electron donor group is selected from the group consisting of OH and NR₁ R₂, where R₁ and R₂ are individually selected from the group consisting of H and C₁ -C₄ alkyl groups.

5. Security paper as set forth in claim 1, wherein said dyestuff is a salt selected from the group consisting of alkali metal and alkaline earth metal salts of 3-hydroxy-pyrene-5,8,10-trisulfonic acid.