Oil-base ballpoint ink composition and oily ballpoint pens

• US 7,172,648 B2
• Filed: 01/28/2003
• Issued: 02/06/2007
• Est. Priority Date: 02/04/2002
• Status: Expired due to Term

• Current Assignee: Mitsubishi Pencil Company Limited
• Original Assignee: Mitsubishi Pencil Company Limited
• Inventors: Ichikawa, Shuji
• Primary Examiner(s): Lorengo; J. A.
• Assistant Examiner(s): Faison-Gee; Veronica
• Application Number:
  US10/503,393
• Publication Number:
  US 20050207824A1
• Time in Patent Office: 1,470 Days
• Field of Search: 106/31.58, 106/31.86
• US Class Current: 106/31.58
• CPC Class Codes: C09D 11/18 specially adapted for ball-point writing instruments

Abstract

A ballpoint ink composition capable of preventing a blobbing phenomenon by controlling the volatility of the ink solvent to prevent extreme drying on the ball surface and control the internal cohesion of the ink is provided, which is an oil-based ballpoint ink composition comprising, as the main solvent, a solvent represented by the following chemical structural formula and further containing at least one or more surfactant selected from the group consisting of a polyoxyethylene alkyl ether, a fatty acid polyoxyethylene alkyl ether, a polyethylene glycol fatty acid ester, a polyoxyethylene glycerin fatty acid ester and a polyoxyethylene sorbitan fatty acid ester:

(wherein R¹, R² and R³ each is independently H or CH₃).

Claims

1. An oil-based ballpoint pen ink composition, comprising

at least one solvent selected from 3-methyl-1,3-butanediol, 1,3-butanediol, 3-methyl-3-methoxy-1-butanol and 3-methoxy-1-butanol,

said at least one solvent being contained in an amount of at least 50 mass % of all solvents in said ink composition,

said ink composition further containing at least one surfactant selected from the group consisting of:

a) a polyoxyethylene alkyl ether represented by the following formula;

R—

O—

(CH₂—

CH₂O)_nH

wherein R is an alkyl group and n is an integer of three or more,

b) a fatty acid polyoxyethylene alkyl ether represented by the following formula;

2. The oil-based ballpoint ink composition as claimed in claim 1, which further comprises, as an auxiliary solvent, at least one member selected from an alcohol, a polyhydric alcohol and a glycol ether.

3. The oil-based ballpoint ink composition as claimed in claim 1, which further comprises polyvinylbutylal in an amount of 1 to 30 mass % based on the ink composition.

4. An oil-based ballpoint pen comprising an ink reservoir tube equipped with a ballpoint pen tip at the distal end and an oil-based ballpoint ink composition housed in the ink reservoir tube, wherein said oil-based ballpoint ink composition is the oil-based ballpoint ink composition claimed in claim 1.

5. The oil-based ballpoint pen as claimed in claim 4, which comprises an ink follower within the ink reservoir tube.

6. The oil-based ballpoint pen as claimed in claim 4, wherein a metal or ceramic ball is used.