Oily ink for writing instrument

• US 6,655,867 B2
• Filed: 04/26/2002
• Issued: 12/02/2003
• Est. Priority Date: 09/20/1999
• Status: Expired due to Fees

• Current Assignee: Sakura Color Products Corporation
• Original Assignee: Sakura Color Products Corporation
• Inventors: Omatsu, Takeshi, Inoue, Hiroshi
• Primary Examiner(s): Mancene, Gene
• Assistant Examiner(s): LE, HUYEN D
• Application Number:
  US10/133,027
• Publication Number:
  US 20030086744A1
• Time in Patent Office: 585 Days
• Field of Search: 401/141, 401/142, 523/161, 523/160, 106/31.6, 106/31.64
• US Class Current: 401/142
• CPC Class Codes: C09D 10/00 Correcting fluids, e.g. fluid media for correction of typographical errors by coating correcting errors by overprinting B41J29/36
• CPC Class Codes: C09D 11/16 Writing inks
• CPC Class Codes: C09D 11/18 specially adapted for ball-point writing instruments

Abstract

A writing instrument has an ink containment tube and a pen tip equipped at one end of the ink containment tube with an oily ink contained in the ink containment tube. The oily ink shows pseudo-plasticity fluidity and comprises a colorant, a resin, an organic solvent and a gelling agent.

Claims

1. A writing instrument having an ink containment tube and a pen tip equipped at one end of said ink containment tube, wherein an oily ink and an ink follower contacting said oily ink and following the outflow of said oily ink are contained in said ink containment tube and said oily ink is an ink comprising a colorant, a resin, an organic solvent, and a gelling agent and showing pseudo-plasticity fluidity.

2. A writing instrument as set forth in claim 1, wherein said getting agent is a soluble gelling agent.

3. A writing instrument as set forth in claim 1, wherein said gelling agent is a soluble gelling agent having solubility of 0.1 to 20% by weight to said organic solvent at the temperature of 20°

C.

4. A writing instrument as set forth in claim 1 wherein said gelling agent comprises a soluble gelling agent with the solubility of from about 0.1 to about 20% by weight at a temperature of 20°

C. to the said organic solvent, and the viscosity of the ink is not less than 700 mPa·

s when the rate of shear is 0.1 (1/s) and not greater than 500 mPa·

s when the rate of shear is 100 (1/s).

5. A writing instrument as set forth in claim 1, wherein the viscosity of the ink is not less than 900 mPa·

s when the rate of shear is 0.1, (1/s) and not greater than 250 mPa·

s when the rate of shear is 100 (1/s).

6. A writing instrument as set forth in claim 1, wherein said colorant comprises titanium dioxide.

7. A writing instrument as set forth in claim 6, wherein titanium dioxide is present in an amount from about 20 to about 60% by weight wit respect to the total amount of the ink.

8. A writing instrument as set forth in claim 1, wherein said gelling agent comprises aluminum 2-ethylhexoate.

9. A writing instrument as set forth in claim 1, wherein said gelling agent comprises disoap-type aluminum 2-ethylhexoate.

10. A writing instrument as set forth in claim 1, wherein said gelling agent is present in an amount from about 0.05 to about 5% by weight wit respect to the total amount of the ink.

11. A writing instrument as set forth in claim 1, wherein said organic solvent comprises a hydrocarbon solvent.

12. A writing instrument as set forth in claim 11, wherein said organic solvent comprises methylcyclohexane.

13. A writing instrument as set forth in claim 1, wherein said organic solvent comprises a quick-drying organic solvent having a vapor pressure of at least 20 mmHg at 20°

C.

14. A writing instrument as set forth in claim 1, wherein said organic solvent is present in an amount from about 10 to about 70% by weight with respect to the total amount of the ink.

15. A writing instrument as set forth in claim 1, wherein said resin comprises an alkylphenol resin, a rosin-modified resin, or an alkyd resin.

16. A writing instrument as set forth in claim 1, wherein said resin is present in an amount from about 3 to about 30% by weight with respect to the total amount of the ink.

20. A writing instrument as set forth in claim 1, wherein an ink follower is so contained in the said ink containment tube as to come in contact with the said oily ink, and the said ink follower is composed of at least a first layer that comes in contact with the oily ink and a second layer that comes in contact with said first layer, and said first layer is aqueous gel-type substance and said second layer is an organic liquid with an involatile or a nonvolatile property.

21. A writing instrument as set forth in claim 20, wherein said aqueous gel-type material comprises a water-soluble polymer as gelling agent.

22. A writing instrument as set forth in claim 21, wherein said water soluble polymer comprises a polysaccharide.

23. A writing instrument as set forth in claim 1, wherein the writing instrument comprises at least any one of a ball, a roller and a rod at an ink outflow part of said pen tip.

24. A writing instrument as set forth in claim 1, wherein said ink can be visually observed from outside said writing instrument.

25. A method of using a writing instrument as set forth in claim 1 comprising opacifying a misspelling by writing on the misspelling without shaking or stirring said writing instrument.

17. A writing instrument as set forth in clam 1, further comprising a nonionic surface-active agent.

18. A writing instrument as set forth in claim 17, wherein said nonionic surface-active agent comprises a higher alcohol ethylene oxide addition product, an alkylphenol ethylene oxide addition product, or a sorbitan aliphatic acid ester addition product.

19. A writing instrument as set forth in claim 17, wherein said nonionic surface active agent is present in an amount from 0.3 to about 5% by weight with respect to the total amount of the ink.