Oil-base ballpoint ink composition and oily ballpoint pens

• US 20050207824A1
• Filed: 01/28/2003
• Published: 09/22/2005
• Est. Priority Date: 02/04/2002
• Status: Active Grant

• Current Assignee: Mitsubishi Pencil Company Limited
• Original Assignee: Mitsubishi Pencil Company Limited
• Inventors: Ichikawa, Shuji
• Granted Patent: US 7,172,648 B2
• Time in Patent Office: Days
• US Class Current: 401/209
• 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 ink composition comprising, as the main solvent, a solvent represented by the following chemical structural formula:

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

2. The oil-based ballpoint ink composition as claimed in claim 1, wherein the addition molar number of ethylene oxide constituting said surfactant is from 3 to 50, the alkyl group contained in said surfactant is an alkyl group derived from an acid or an alcohol and having from 10 to 30 carbon atoms, and said surfactant is blended in an amount of 0.1 to 20 mass % in total based on the ink composition.

3. The oil-based ballpoint ink composition as claimed in claim 1 or 2, which comprises a surfactant selected from said surfactants and having an HLB of 7 to 16 and an oily appearance at 25°

C.

4. The oil-based ballpoint ink composition as claimed in any one of claims 1 to 3, wherein said main solvent is at least one member selected from 3-methyl-1,3-butanediol, 1,3-butanediol, 3-methyl-3-methoxy-1-butanol and 3-methoxy-1-butanol.

5. The oil-based ballpoint ink composition as claimed in any one of claims 1 to 4, which further comprises, as an auxiliary solvent, at least one member selected from an alcohol, a polyhydric alcohol and a glycol ether.

6. The oil-based ballpoint ink composition as claimed in any one of claims 1 to 5, which further comprises a resin in an amount of 1 to 30 mass % based on the ink composition.

7. The oil-based ballpoint ink composition as claimed in any one of claims 1 to 6, wherein the polyoxyethylene alkyl ether is a compound represented by the following formula:

R—

O—

(—

CH₂CH₂O)_nH

(wherein R is an alkyl group and n is an integer of 1 or more).

8. The oil-based ballpoint ink composition as claimed in any one of claims 1 to 6, wherein the fatty acid polyoxyethylene alkyl ether is a compound represented by the following formula:

(wherein R and R₁ each is an alkyl group and n is an integer of 1 or more).

9. The oil-based ballpoint ink composition as claimed in any one of claims 1 to 6, wherein the polyethylene glycol fatty acid ester is a compound represented by the following formula:

(wherein R is an alkyl group and n is an integer of 1 or more).

10. The oil-based ballpoint ink composition as claimed in any one of claims 1 to 6, wherein the polyoxyethylene glycerin fatty acid ester is a compound represented by the following formula:

(wherein R is an alkyl group, and n and m each is an integer of 1 or more),

11. The oil-based ballpoint ink composition as claimed in any one of claims 1 to 6, wherein the polyoxyethylene sorbitan fatty acid ester is a compound represented by the following formula:

(wherein R is an alkyl group, and 1, m and n each is an integer of 1 or more).

12. 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 any one of claims 1 to 11.

13. The oil-based ballpoint pen as claimed in claim 12, which comprises an ink follower within the ink reservoir tube.

14. The oil-based ballpoint pen as claimed in claim 12 or 13, wherein a metal or ceramic ball is used.