JPS5948036B2 - water-based ink composition - Google Patents

Description

[Detailed Description of the Invention] This invention is applicable to fountain pens as well as felt-tip pen type writing instruments.
The present invention relates to an aqueous ink composition suitable for drafting and recorder use.

More specifically, a water-based ink composition that has favorable characteristics such that the ink does not dry out even when left in atmospheric conditions with the cap removed, and does not spread like feathers on writing paper or bleed through. It is about things. Conventionally, in water-based inks, high-boiling water-soluble organic solvents such as ethylene glycol, propylene glycol, diethylene glycol, thiodiethanol, cellosolve, and acid amides have been used to suppress drying of the ink at the pen tip.

However, when large amounts of these are added, the viscosity of the ink increases, making it difficult for the ink to flow out from the tip of the pen, and when writing on writing paper, it may spread like feathers or seep through. This had the disadvantage that good handwriting could not be obtained. Therefore, the inventors of the present invention have conducted extensive research in order to eliminate the above-mentioned drawbacks of water-based inks. By adding a small amount of an adduct of polyethylene oxide to higher alcohol to water-based ink, the amount of addition is small. Water-based with good performance: the ink does not increase in viscosity and maintains a low viscosity; 2. The ink does not dry at the tip of the pen; 3. Handwriting does not spread like feathers on writing paper or bleed through. He discovered that ink could be obtained and completed this invention.

That is, this invention provides water-based ink with the following general formula (1) R
-O(CH2CH20-)-nH...(1) (in the formula, R is a C20-C26 alkyl group, n is an integer of 5 to 15) and an adduct of polyethylene oxide to higher alcohol This is a water-based ink composition containing the following.

The compound represented by the above general formula is a colorless oil that can be easily obtained by adding ethylene oxide to the corresponding higher alcohol, such as moidocosyl polyethylene glycol ether, monoeicosyl polyethylene glycol ether, monoceryl polyethylene glycol Ether etc. are mentioned as a corresponding compound. The appropriate amount of these compounds to be added is 0.05 to 1% by weight based on the ink, since dispersion will be poor if the amount is 1% by weight or more, and if it is less than 0.05% by weight, the effect will be uneven. The method for adding the ink to the ink is as simple as stirring and dispersing the ink. The water-soluble dye used in the ink of the present invention is not particularly limited as long as it is sufficiently soluble in the ink solvent, and can be appropriately selected from direct dyes, acid dyes, and basic dyes.

The ink solvent is suitably water-based, to which is further added 15% by weight or less of a water-based ink solvent such as ethylene glycol, diethylene glycol, polyethylene glycol, thiodiethanol Celsol, pyrrolidone, or the like.

In addition, various surfactants may be added to adjust other properties such as ink flow, or appropriate preservatives and rust preventives may be added as necessary. The ink to which the compound of the present invention represented by the above general formula is added has little effect on the viscosity because the amount added is small, and the ink has a low viscosity and flows out smoothly.

2. The nib prevents the ink from drying out. 3. It does not spread like feathers on writing paper or bleed through.

Although the details of the mechanism that provides the above-mentioned good performance are unknown, the compound represented by the general formula used in this invention has a strong diffusion power on the water surface and easily forms a monomolecular film. Because the monomolecular film has a strong evaporation suppressing power, when the ink becomes slightly concentrated at the pen tip, a very thin film of the compound is formed on the ink surface, which prevents water, the main solvent, from evaporating. It is presumed that the above-mentioned favorable effect 2, that the ink does not easily dry up at the pen tip, can be obtained. Therefore, since there is almost no decrease in water content, the above-mentioned effects 1 and 3 are naturally obtained. The present invention will be explained below with reference to Examples.

Note that "middle part" in the examples refers to parts by weight. A black ink was obtained by adding and dissolving the dye of the composition (C) to a mixed solvent of the composition (ByVE) and stirring well. Even when written on thin paper, the handwriting was extremely clear without smearing.Also, the handwriting was kept at room temperature (temperature 19 to 2) with the cap removed.
Even after being left for 10 hours at a temperature of 2° C. and a humidity of 60 to 70%, the handwriting remained clear without any strain. On the other hand, when writing with a felt-tip pen made by filling the above ink with black ink prepared using the exact same formulation as in the example except that no scouring substance was added,
When the cap was removed and left at room temperature, force strain occurred after 2 hours.

Therefore, in order to have the same pen tip drying resistance as in the example, it was necessary to reduce the amount of water to 62 parts and increase the amount of ethylene glycol to 25 parts instead. The viscosity of the ink in this case is the ink viscosity of Example 1.71c. p/2.32 c. for 25°C. Since the ink had a large p/25°C, the ink flowed out worse than the ink of the example when used as a writing instrument with a nib for fine writing. Furthermore, the handwriting written on thin paper had more bleeding than the ink of the example. As mentioned above, the ink of this invention has low viscosity, does not dry easily, and does not bleed easily, so it is suitable not only for use in felt-tip pen type writing instruments, but also as an ink for fountain pens, drafting, and recording paper. .

Claims (1)

[Claims] 1. In an ink in which a water-soluble dye is dissolved in a water-based mixed solvent, 0.05 to 1% by weight of an adduct of polyethylene oxide to a higher alcohol represented by general formula (1) is blended. A water-based ink composition characterized by: ▲There are mathematical formulas, chemical formulas, tables, etc.▼・・・・・・(1)
(Here, R is an alkyl group of C_2_0 to C_2_6, n
represents an integer from 5 to 10. )