Process for making and detecting anti-counterfeit paper

• US 6,045,656 A
• Filed: 12/21/1998
• Issued: 04/04/2000
• Est. Priority Date: 12/21/1998
• Status: Expired due to Fees

• Current Assignee: Meadwestvaco (WestRock Company)
• Original Assignee: Westvaco Corporation (Meadwestvaco Corporation)
• Inventors: Foster, James Joseph, Mulcahy, Leo Thomas
• Primary Examiner(s): FORTUNA, JOSE A
• Application Number:
  US09/216,765
• Time in Patent Office: 470 Days
• Field of Search: 162/140, 162/134, 162/135, 162/137, 162/162, 162/158, 162/183, 162/181.1, 162/181.8, 162/184, 162/185, 162/9, 162/182, 162/141, 283/72, 283/89, 283/92, 428/206, 428/207, 428/195, 428/211, 428/916
• US Class Current: 162/140
• CPC Class Codes: D21F 1/44 Watermarking devices

Abstract

This invention relates to a method for producing anti-counterfeit paper. Such processes of this type, generally, add a certain percentage of wood fiber lumens which have been loaded with one or more fluorescent agents. These wood fiber lumens would look normal under regular light, but will glow when exposed to various manners of radiation.

Claims

1. A method of producing a radiation light source detectable, anti-counterfeit paper, wherein said method is comprised of the steps of:

dissolving a soluble fluorescent dye in a solvent;

dewatering wood fibers having lumens to a solids content of up to 50% solids;

mixing said dissolved fluorescent dye with said dewatered wood fibers such that said fluorescent dye is loaded into said lumens of said fibers;

cleaning said loaded wood fibers to substantially remove any excess fluorescent dye located on the outside of said wood fiber lumens;

sealing said fluorescent dye substantially inside said lumens of said wood fibers;

removing said fluorescent dye loaded wood fibers;

drying said loaded wood fibers;

incorporating said cleaned, lumen loaded wood fibers into a papermaking pulp furnish at a concentration of Z₂ of said total furnish, where Z₂ (ppm)=concentration of lumen loaded fibers in furnish= ##EQU3## where Z₁ =amount of lumen loaded fibers in furnish in lbs/ton of fiber wherein said cleaned, lumen loaded wood fibers are incorporated into said furnish at a concentration of between at least one parts per billion up to 25%;

forming said lumen loaded furnish into an anti-counterfeit paper; and

wherein said fluorescent dye in said lumen loaded fibers can be detected by employing a radiation light source.

2. The method, as in claim 1, wherein said solvent is further comprised of:

Methanol.

3. The method, as in claim 1, wherein said wood fibers are dewatered to a solids content of less than 30% solids.

4. The method, as in claim 1, wherein said fluorescent dye is further comprised of:

an optically active dye.

5. The method, as in claim 1, wherein said radiation light source is further comprised of:

an infrared light.

6. The method, as in claim 1, wherein said radiation light source is further comprised of:

an ultraviolet light.

7. The method, as in claim 1, wherein said Z₁ or said amount of lumen loaded fibers in furnish in lbs/ton is estimated according to:

##EQU4## where u=concentration of loaded fibers in furnish in ppm, and where x=amount of dye in one fiber.