Erasable inks

• US 5,599,853 A
• Filed: 10/07/1994
• Issued: 02/04/1997
• Est. Priority Date: 01/29/1993
• Status: Expired due to Term

• Current Assignee: Berol Corp (Newell Brands Inc.)
• Original Assignee: Gillette Company (The Procter & Gamble Company)
• Inventors: Loftin, Rachel M.
• Primary Examiner(s): Michl, Paul R.
• Assistant Examiner(s): Asinovsky, Olga
• Application Number:
  US08/319,927
• Time in Patent Office: 851 Days
• Field of Search: 524/575, 523/160, 523/161, 523/164, D19/41, D19/81, 401/103
• US Class Current: 523/160
• CPC Class Codes: C09D 109/08 Latex
• CPC Class Codes: C09D 11/16 Writing inks

Abstract

An aqueous-based erasable ink composition suitable for use in highlighters and other writing instruments includes a styrene-butadiene copolymer and a water-insoluble pigment. It preferably also includes a release agent and an anti-oxidant, and has a viscosity of between 10 cps and 30 cps.

Claims

1. A writing instrument comprising an outer body;

a writing tip at one end of said body;

a reservoir included within said body and in fluid communication with said writing tip; and

within said reservoir an aqueous-based, non-shear thinning ink that is erasable from and capable of forming a read-through tracing on 60 lb. offset printing paper, said ink comprising water, a colorant, and a styrene-butadiene copolymer having a styrene content of less than about 35%.

2. A writing instrument of claim 1 wherein said colorant is a fluorescent colorant.

3. A writing instrument of claim 1 wherein said ink has a viscosity of from about 10 to 30 cps.

4. A writing instrument of claim 1 wherein said ink further comprises a release agent.

5. A writing instrument of claim 1 wherein said ink further comprises an antioxidant.

13. A writing instrument of claim 1 wherein said ink has a styrene-butadiene copolymer solids content less than 50% by weight.

14. A writing instrument of claim 1 wherein said ink has a styrene-butadiene copolymer solids content between and 40% by weight.

15. A writing instrument of claim 1 wherein said styrene-butadiene copolymer has a Mooney value of at least 90.

16. A writing instrument of claim 1 wherein said copolymer has a styrene:

butadiene ratio of between 10;

90 and 35;

65.

6. A method of providing an erasable marking on a paper substrate comprising

providing a marker comprising an outer body;

a writing tip at one end of said body;

an ink reservoir included within said body and in fluid communication with said writing tip; and

, within said ink reservoir, an aqueous-based ink that is erasable from 60 lb. offset paper, said ink comprising water, a colorant, and a styrene-butadiene copolymer having a styrene content of less than about 35%, and

contacting said writing tip with a paper substrate to transfer said ink from said writing tip to said paper substrate to provide an erasable marking on said paper substrate.

7. A method of claim 6 further comprising the step of erasing said erasable marking from said paper substrate.

8. A method of claim 6 wherein said ink further comprises a release agent.

9. A method of claim 6 wherein said colorant is a fluorescent pigment.

10. A method of claim 6 wherein said erasable marking is a read-through tracing, made over an underlying marking to highlight said underlying marking.

11. A method of claim 6 wherein said ink further comprises an antioxidant.

12. A method of claim 9 wherein said erasable marking is a read-through tracing, made over an underlying marking to highlight said underlying marking.

17. The method of claim 6 wherein said ink has a styrene-butadiene copolymer solids content less than 50% by weight.

18. The method of claim 6 wherein said ink has a styrene-butadiene copolymer solids content between 10% and 40% by weight.

19. The method of claim 6 wherein said styrene-butadiene copolymer has a Mooney value of at least 90.

20. The method of claim 6 wherein said copolymer has a styrene:

butadiene ratio of between 10;

90 and 35;

65.

21. The method of claim 6 wherein said ink has a viscosity of from about 10 to 30 cps.