JPH0768487B2 - Ink composition for water-based ballpoint pen - Google Patents

Description

TECHNICAL FIELD The present invention relates to an aqueous ink composition for a ballpoint pen, which comprises water and a water-soluble organic solvent as a main component of a solvent and is excellent in anti-drying property.

(Prior Art) In general, the ink for water-based ballpoint pens has a lower boiling point of water, which is the main component of the solvent, than the ink for oil-based ballpoint pens, so when left without a cap, a dye that is a pigment at the tip of the pen tip The pigment, and other additives solidify, and as a result, the rotation of the ball is hindered, which causes writing defects such as blurring, and the possibility that writing may become impossible.
In order to prevent these coins, a water-soluble organic solvent having a high boiling point and high hygroscopicity, such as ethylene glycol, propylene glycol, or diethylene glycol, has been added. However, these water-soluble organic solvents only have the effect of delaying the volatilization of the solvent, and when left in an environment of high temperature and low humidity, or when left for a long time, dyes and pigments, and other additives. Not only is there a drawback that it cannot prevent the solidification, but if the addition amount becomes excessive, it will rather cause bleeding and a decrease in the dryness of the drawn line.

(Problems to be Solved by the Invention) An object of the present invention is to solve such problems of the conventional ink for water-based ballpoint pens and to provide an ink composition for water-based ballpoint pens, which is excellent in drying resistance.

(Means for Solving Problems) The ink composition for a water-based ballpoint pen of the present invention devised to solve the above problems is a water-soluble dye or water-based pigment,
Water-soluble organic solvent, and the following general formula in water The composition is characterized in that the compound A represented by

Here, the compound A is a polyhydric alcohol / ether and is obtained by condensation of glycerin. The addition amount of the compound A is effective when it is in the range of 1 to 50% by weight, but it is 20 to 20 in the system which does not use the other water-soluble organic solvent for volatilization prevention described above.
It may be added in an amount of 30% by weight or more, but it is desirable to control the content within the range of several% to 10% in a system using another water-soluble organic solvent for volatilization prevention.

(Operation) The compound A added in the present invention is a high-boiling-point liquid having excellent hygroscopicity, has an action of suppressing volatilization of volatile components of the ink, and hardly vaporizes itself. Further, it has a hydroxyl group and an ether bond in the molecule, and has the property of helping the dissolution of dyes and other components and not hindering the dispersion of the pigment. Therefore, the addition of the compound A has the effect of preventing the solidification of the ink components even when left without a cap for a long period of time or in a high temperature and low humidity environment.

(Example) Example 1 The ink compositions shown in the table below are stirred at room temperature for 5 hours, allowed to stand at room temperature, and then filtered to obtain an aqueous ballpoint pen ink.

Example 2 The ink composition shown in the following table is treated in the same manner as in Example 1 to obtain an aqueous ballpoint pen ink.

Example 3 The ink composition shown in the table below is treated in the same manner as in Example 1 to obtain an aqueous ballpoint pen ink.

(Effects of the Invention) Ink of each of the above-described Examples 1, 2, and 3;
Comparative Example 1 (the composition of Example 1 without the compound A), Comparative Example 2 (the composition of the example 2 without the compound A), Comparative Example 3 (the compound A of the Example 3 with ethylene glycol) Each of the inks (substituted) was filled in a ball-point pen using batting, and left for one month at room temperature with the cap removed to perform a writing test. As a result, Examples 1, 2 and The ballpoint pen using the ink of Example 3 was able to write smoothly without scratching compared to the first stroke. On the other hand, the ball-point pens using the inks of Comparative Examples 1, 2, and 3 were incapable of writing after the first stroke or were unwritable. As is clear from the test results, the water-based ballpoint pen ink composition of the present invention has a very remarkable anti-drying effect.

Claims (2)

[Claims] 1. A water-soluble dye or water-based pigment, a water-soluble organic solvent, and water having the following general formula: An aqueous ink composition for a ball-point pen, wherein the compound A represented by the following formula is added. 2. The ink composition for water-based ballpoint pens according to claim 1, wherein the amount of the compound A added is 1 to 50% by weight.