JP3139118B2 - Oil-based ink composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an oil-based ink composition excellent in drying resistance of a pen tip, and more particularly, to an oil-based ink composition in which the pen tip is hard to dry even if the cap is left unplugged for a long time. It is about things.

[0002]

2. Description of the Related Art Conventionally, writing implements using oil-based inks are:
It is widely used because it can be written on both absorbent surfaces such as paper and cloth and non-absorbent surfaces such as plastic, glass and metal, and has quick drying properties. In recent years, studies have been made to reduce the toxicity of oil-based inks, and alcohol-based solvents have been used as solvents. However, such a highly safe oil-based ink composition tends to evaporate the solvent. Therefore, if the writing instrument using this ink is left with the cap removed, the solvent in the ink will evaporate from the pen tip. If the solvent in the ink evaporates at the pen tip, a dye, a resin or the like precipitates and clogs on the surface or inside of the pen tip, and the ink is not discharged from the pen tip. Therefore, there was a problem that the handwriting was faded and writing became impossible. Also, no satisfactory oil-based metal-containing dye was used as the coloring material, which was relatively soluble in alcohol solvents. Therefore, in order to further suppress the evaporation of the solvent in the ink, various anti-drying agents such as a high boiling point solvent and a surfactant have been added to the ink, and studies have been made to make the pen tip difficult to dry.

[0003]

However, in an oil-based ink using an alcohol-based solvent and an oil-based metal-containing dye, the effect can be said to be sufficient even if a high-boiling solvent or a surfactant is added. Did not. In addition, if a large amount of a surfactant is added to the ink in an attempt to achieve satisfactory drying resistance of the pen tip, there is a problem that ink leaks from the pen tip or bleeds in handwriting. .

[0004]

An alcohol having 4 or less carbon atoms is used.
SUMMARY OF THE INVENTION The gist of the present invention is an oil-based ink composition comprising at least an oil-based solvent, an oil-based metal-containing dye and an organic compound represented by the following general formula (Formula 2).

[0005]

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[0006] The oil-based metal-containing dye is used as a coloring agent, and has a stronger coloring power than ordinary oil-based dyes,
It has the advantage of having good fastness such as light fastness. Specifically, varifa black 3804, 3806, 3808, 3810, 3820, 3840, varifa stoier-3104, varifa stred 3
304, 3305 (all manufactured by Orient Chemical Co., Ltd.), Eizen Spiron Black BH Special, G
SH Special, Aizen Spiron Yellow-GRH, Aizen Spiron Red BEH, and GEH (both manufactured by Hodogaya Chemical Industry Co., Ltd.), etc., and these can be used alone or in combination of two or more. The amount used is preferably from 5 to 25% by weight based on the total amount of the ink.

Alcohol solvents having 4 or less carbon atoms are used as ink solvents. Specifically, methanol solvents are used.
, Ethanol, n-propanol, isopropanol
And n-butanol and isobutanol.
These can be used alone or in combination of two or more.
The amount used is preferably 40 to 90% by weight based on the total amount of the ink.

The organic compound represented by the general formula (Chemical Formula 2) is used to suppress the drying of the pen tip when the writing implement using an oil-based ink to which the organic compound is added is taken off and left to stand. And specifically,
3-methyl-3-methoxybutanol, 3-methyl-3
And methoxypentanol. As a commercially available product, Solfit (manufactured by Kuraray Isoprene Chemical Co., Ltd.) is available.
% By weight is preferred. Here, when the number of carbon atoms of the alkyl group represented by R in (Chemical Formula 2) is 3 or more, the polarities of the hydroxyl group and the methoxy group become weak, so that the affinity with the alcohol-based solvent or the oil-based metal-containing dye is low. Is not preferred.

In addition to the above-mentioned essential components, natural / synthetic resins conventionally used as a fixability-imparting agent and an ink viscosity modifier can be used. Specifically, rosin, rosin ester, rosin-modified glycerin ester, rosin-modified Rosin resins such as maleic acid resin, rosin-modified phenol resin, rosin-modified phenol glycerin ester, cellulose resins such as ethyl cellulose and nitrocellulose, petroleum resins, ketone resins, phenol resins, etc. Is mentioned. Specifically, gum rosin ww is used as a rosin resin.
(Manufactured in China), Tamanol 100s as phenol resin
(Manufactured by Arakawa Chemical Industries), as a ketone resin,
501 (Hitachi Chemical Co., Ltd.) and the like, and the use amount thereof is preferably 1 to 30% by weight based on the total amount of the ink. Further, various additives such as a rust inhibitor, a wetting agent, a viscosity modifier, an antifoaming agent, a surfactant and the like can be appropriately used as needed.

[0010]

The reason why the oil-based ink composition of the present invention has excellent pen tip drying resistance and prevents blurring of handwriting is presumed as follows. The organic compound represented by the above general formula (Chemical Formula 2) used in the present invention has a low evaporation rate due to its molecular structure having a specific polarity, and has a specific solubilizing power for an oily metal-containing dye. have. That is, it is presumed that the alcohol-based solvent having 4 or less carbon atoms and the oil-based metal-containing dye have a suitable affinity at the pen tip to prevent precipitation of the dye, thereby suppressing drying of the ink at the pen tip.

[0011]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to Examples. In the Examples and Comparative Examples, "parts" means "parts by weight".

(Example 1) Ethanol 58.0 parts Isopropyl alcohol 10.0 parts Gum rosin WW (rosin resin, made in China) 5.0 parts Varifast Black 3808 (oil-based metal-containing dye, Orient Chemical) 17.0 parts Solfit (Kuraray Isoprene Chemical Co., Ltd.) 5.0 parts Benzyl alcohol 5.0 parts The above components are mixed, and the mixture is stirred for 2 hours with a commercially available stirrer to obtain an oily black color. An ink was obtained.

(Example 2) 28.0 parts of ethanol 45.0 parts of isopropyl alcohol Tamanol 100S (phenol resin manufactured by Arakawa Chemical Industry Co., Ltd.) 5.0 parts 17.0 parts of varifast black 3808 Solfit (Kuraray Isoprene Chemical Co., Ltd.) 5.0 parts The above components were mixed and stirred with a commercially available stirrer for 2 hours to obtain an oily black ink.

(Example 3) Ethanol 65.0 parts n-propanol 10.0 parts Hitachil 1505 (ketone-based resin, manufactured by Hitachi Chemical Co., Ltd.) 5.0 parts Varifa Stread 3305 (oil-based) Metal-containing dye, manufactured by Orient Chemical Industry Co., Ltd.) 10.0 parts 3-methyl-3-methoxypentanol 5.0 parts Hisolve DM (diethylene glycol monomethyl ether, manufactured by Toho Chemical Industry Co., Ltd.) 0 parts The above components were mixed and stirred with a commercially available stirrer for 2 hours to obtain an oily red ink.

Comparative Example 1 An oil-based black ink was obtained in the same manner as in Example 1 except that Solfit was removed from Example 1 and ethanol was added in that amount.

Comparative Example 2 An oil-based black ink was obtained in the same manner as in Example 2 except that Solfit was removed from Example 2 and that amount of ethanol was added.

(Comparative Example 3) An oil-based red ink was obtained in the same manner as in Example 3 except that Solfit was added to Example 3 and that amount of Highsolve DM was added.

(Comparative Example 4) Ethanol 32.0 parts Isopropyl alcohol 45.0 parts Tamanol 100S (phenol resin manufactured by Arakawa Chemical Industry Co., Ltd.) 5.0 parts Varifast Black 3808 17.0 parts 1.0 part of decagrin 5-O (surfactant, manufactured by Nikko Chemicals Co., Ltd.) 1.0 parts of the above components were mixed and stirred with a commercially available stirrer for 2 hours to obtain an oily black ink.

Comparative Example 5 An oily black ink was obtained in the same manner as in Example 2 except that decagrin 5-O was added instead of Solfit.

[0020]

The oil-based inks obtained in Examples 1 to 3 and Comparative Examples 1 to 5 are filled in a commercially available batting-type writing implement (synthetic resin nib, extra-fine type, MF50, manufactured by Pentel Co., Ltd.) Table 1 shows the results of tests on drying resistance, drying resistance, ink leakage, and handwriting bleeding.

[0021]

[Table 1] Pen tip drying resistance: Remove the cap of the writing implement filled with ink, leave it indoors (temperature 20 ° C, humidity 50%),
Writing was performed every 0 minutes, and the time until handwriting was blurred was measured. Ink leakage: writing implement filled with the ink at 50 ° C, 2
It was left for 4 hours, and the degree of ink leakage from the pen tip was visually evaluated. ○-no leakage, x-leakage. Handwriting bleeding: 10 points with a writing instrument filled with the ink.
A line of cm was written and the degree of bleeding of the handwriting was visually evaluated. ○ -No bleed, x-bleed.

As described above, the oil-based ink composition of the present invention, when used in a writing instrument, is excellent in the drying resistance of the pen tip, and has little blur of handwriting when the cap is removed and left. It is excellent in practicality without causing ink leakage from the pen tip and blurring of handwriting.

Claims (1)

(57) [Claims] 1. An oil-based ink composition comprising at least an alcohol solvent having 4 or less carbon atoms, an oil-based metal-containing dye, and an organic compound represented by the following general formula (1). Embedded image