Eradicable inks

• US 5,916,357 A
• Filed: 03/25/1997
• Issued: 06/29/1999
• Est. Priority Date: 03/25/1997
• Status: Expired due to Term

• Current Assignee: Berol Corp (Newell Brands Inc.)
• Original Assignee: Gillette Company (The Procter & Gamble Company)
• Inventors: Hopson, Russell E., Wang, Yichun
• Primary Examiner(s): Harrison, Robert H.
• Application Number:
  US08/823,416
• Time in Patent Office: 826 Days
• Field of Search: 523/161, 106/31.01, 106/31.13, 106/31.23, 106/31.27, 106/31.4, 106/31.43, 252/183.13
• US Class Current: 106/31.23
• CPC Class Codes: C09B 69/02 Dyestuff salts, e.g. salts of acid dyes with basic dyes for Na, K or NH4+ salts or for chlorides, sulfates or chlorozincates, see the relevant dye groups
• CPC Class Codes: C09D 11/17 characterised by colouring agents

Abstract

An eradicable ink contains an essentially non-aqueous solvent and a colorant, dissolved in the solvent, that changes color if contacted with a sulfite or an amine. Moreover, a water soluble colorant containing a counterion hydrophilic can be converted into a water insoluble colorant by substituting a hydrophobic counterion for the hydrophilic counterion.

Claims

1. An eradicable ink for use in a ball pen, comprising a solvent, containing less than 2% water, comprising between 40% and 80% by weight of the ink of a non-volatile organic solvent and a sufficient amount to impart color to an ink mark of a colorant which is a triarylmethane dye having a hydrophobic counterion wherein said dye is soluble in phenyl cellosolve, said colorant, being dissolved in said solvent, and changing color if contacted with a sulfite or an amine.

2. The eradicable ink of claim 1, wherein said colorant decolorizes if contacted with a sulfite.

3. The eradicable ink of claim 1, wherein said colorant decolorizes if contacted with an amine.

4. The eradicable ink of claim 1, further comprising a polymer.

5. The eradicable ink of claim 4 wherein said ink comprises between 10% and 45% of said colorant by weight of the ink, and between 5% and 30% of said polymer by weight of the ink.

6. An eradicable ink for use in a writing instrument, comprising a solvent comprising between 40% and 80% by weight of the ink of a non-volatile organic solvent and a sufficient amount to impart color to an ink mark of a colorant which is a triarylmethane dye having a hydrophobic counterion wherein said dye is soluble in phenyl cellosolve, said colorant, being dissolved in said solvent, and changing color if contacted with a sulfite or an amine.

7. The eradicable ink of claim 6, wherein said colorant decolorizes if contacted with a sulfite.

8. The eradicable ink of claim 6, wherein said colorant decolorizes if contacted with an amine.

9. The eradicable ink of claim 6 wherein said ink comprises between 10% and 45% of said colorant by weight of the ink.

10. The eradicable ink of claim 6, wherein said solvent comprises less than 10% water by weight.

11. The eradicable ink of claim 6, wherein said triarylmethane dye comprises a n-alkylpyridinum salt.

12. The eradicable ink of claim 6, wherein said triarylmethane dye comprises a tetraalkyl ammonium salt.

13. The eradicable ink of claim 6, wherein said triarylmethane dye comprises a tetraalkyl phosphonium salt.

14. The eradicable ink of claim 12, wherein said triarylmethane dye comprises a P,P'"'"'-alkylene bis(trialkyl phosphonium) salt.

15. The eradicable ink of claim 12, wherein said triarylmethane dye comprises a N,N'"'"'-alkylene bis(trialkyl ammonium) salt.