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Leach resistant ink for protecting documents from alteration and document protected thereby

  • US 5,058,925 A
  • Filed: 12/13/1989
  • Issued: 10/22/1991
  • Est. Priority Date: 12/13/1989
  • Status: Expired due to Term
First Claim
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1. A leach-resistant ink for protecting documents from alteration by oxidizing agents comprising diphenyl guanidine which becomes colored upon contact with an oxidizing agent and a complexing agent selected from the group consisting of glucose, sucrose, sorbitol, methyl glucoside, and mixtures thereof, which forms a complex with said diphenyl guanidine.

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