JP2001311032A - Oil-based ink composition for ballpoint pen - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an oil-based ink which is used for ballpoint pens and can prevent that the viscosity of the oil-based ink is lowered with the passage of time to cause the dropping or straight flow of the ink. SOLUTION: This oil-based ink composition for ballpoint pens, comprising at least a coloring agent, an organic solvent and a resin, characterized in that the content of water is 1 to 4 wt.% based on the total amount of the ink.

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 for use in a ball-point pen, and more particularly to an ink for writing which is less likely to decrease in viscosity due to moisture absorption even after long-term storage. And ink leakage (DC) that is less likely to drop (bottom) and to leak ink down the chip (DC).

[0002]

2. Description of the Related Art Conventionally, a ballpoint pen is composed of a ballpoint pen tip, an ink storage tube, ink and a pen shaft. The writing with the ballpoint pen is performed by transferring the ink flowing out by the rotation of the ball at the pen tip to the writing surface. At this time, the ink that has not been completely transferred adheres to the outer periphery of the chip holder, and becomes a so-called brush, which stains the writing surface.

[0003] When a ballpoint pen is stored with the tip facing downward for a long time or under high temperature and high humidity, the tip cannot support the ink in the ink storage tube, causing a direct current of the ink to stain the body and clothes. . These phenomena occur when the viscosity of the ink decreases.

[0004] Oil-based ink compositions for ballpoint pens include colorants such as dyes and pigments, solvents such as benzyl alcohol and phenoxyethanol, and ketone resins and xylene resins.
It is made of a resin such as a rosin derivative, polyvinyl pyrrolidone, and polyvinyl butyral. Inks using glycol as a solvent, the glycols have a hygroscopic property, and when stored in a natural environment, the viscosity of the ink decreases due to the moisture absorption, and the performance related to the prevention of bottling and the prevention of direct current is lower than that at the time of manufacturing. There was a problem that it was lowered. In particular, the above problem is likely to occur at high humidity.

[0005] In oil-based inks for ballpoint pens, viscosity is one of the important physical properties that affect writing performance. If the ink viscosity is set higher, the amount of ink flowing out of the ballpoint pen tip will be reduced,
Although the direct current is reduced, on the other hand, there are adverse effects such as a heavy brush feeling and a low drawing line density. The tendency is that the lower the operating conditions of the ballpoint pen, the lower the temperature
growing. On the other hand, when the viscosity of the ink is set low, especially when the use condition of the ballpoint pen is high, the generation of bosses and direct current increases.

There is a method in which the viscosity of the ink is set higher in advance in anticipation of the viscosity decrease due to the lapse of time after the production of the ink. However, in such a method, it is necessary to pass a certain time until the desired viscosity is reached, and since the viscosity of the ink is high immediately after the production, the writing feel is heavy and the writing pen becomes uncomfortable.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to provide a ballpoint pen capable of preventing the viscosity of oil-based ink for a ballpoint pen from decreasing with the passage of time to prevent the occurrence of dents and direct current. It is to provide an oil-based ink for use.

[0008]

Means for Solving the Problems As a result of intensive studies to solve the above-mentioned problems, the present inventor has found that by previously adding water to an oil-based ink composition for a ballpoint pen, the ink is absorbed by moisture in a natural environment. The present inventors have found that a decrease in the viscosity of the resin composition can be reduced, thereby reducing the occurrence of dents and direct current, and arrived at the present invention.

That is, the present invention is as follows. (1) When the oil-based ink composition for a ball-point pen is left in a use environment,
An oil-based ink composition for a ballpoint pen, characterized in that the water content when the water reaches the equilibrium state by absorbing water in the air is previously contained in the ink composition for a ballpoint pen. (2) The oil-based ink composition for a ballpoint pen according to the above (1), wherein the content of water is 1 to 4% by weight based on the total amount of the ink. (3) The oil-based ink composition for a ballpoint pen according to the above (1) or (2), comprising at least a colorant, an organic solvent and a resin.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail. As the colorant used in the present invention, all known dyes and / or pigments used in conventional oil-based inks for ballpoint pens can be used. As a dye,
For example, Spiron Black GMHsp, Spiron Violet C-RH, Spiron Yellow C-2GH (above,
Hodogaya Chemical Co., Ltd.), Barry First Black #
3804, Barry First Violet # 1701,
Barry First Yellow # 3104 (all manufactured by Orient Chemical Industries, Ltd.), auramine, rhodamine, methyl violet, malachite green, crystal violet and the like. Examples of the pigment include titanium oxide, carbon black, phthalocyanine-based, azo-based, anthraquinone-based, quinacridone-based, and microlease color (manufactured by Ciba Geigy). When using these coloring agents, they may be used alone or in combination as appropriate. It is preferable to use the colorant in an amount of 15 to 45% by weight, more preferably 20 to 30% by weight, based on the total amount of the ink.
It is.

The organic solvent used in the present invention is a solvent used in an ordinary oil-based ink composition for a ballpoint pen, that is, a solvent that dissolves or disperses the above-mentioned colorant.
A solvent having a relatively high boiling point, for example, a boiling point of 150 to 350 ° C.
Solvent is used. Examples of such a solvent include benzyl alcohol and phenoxyethanol generally used in oil-based inks for ballpoint pens, carbitols,
Cellosolves, glycols, glycol ethers and the like can be mentioned. These may be used alone or in combination of two or more.

The resin used in the present invention is used to adjust the viscosity of the ink composition, and includes resins used in ordinary oil-based inks for ballpoint pens, such as ketone resins, sulfamide resins, maleic resins, and the like. Ester gum,
Xylene resins, alkyd resins, phenol resins, rosin resins, terpene resins, cumarone-indene resins, polyvinyl pyrrolidone, polyvinyl butyral, and the like. These resins may be used alone or in combination of two or more.

The ink composition of the present invention may contain, if necessary, a rust inhibitor, a preservative, a lubricant, and other additives used in ordinary ballpoint pen inks.

A ballpoint pen product is prepared by filling the oil-based ink for a ballpoint pen obtained by mixing the above components into a tube made of a synthetic resin, for example, polypropylene. When the ball-point pen is placed in a natural environment, when it absorbs about 2 to 4% of water, it almost reaches equilibrium with the outside air, and further changes become extremely slow. When the equilibrium is reached, the viscosity is
It decreases to 40 to 70% of the initial value.

Therefore, the oil-based ink for a ball-point pen is
1-4% by weight, preferably 1%, based on the total amount of the ink.
By adjusting the water content to 3% by weight, when the ballpoint pen is placed in a natural environment, the change in viscosity of the ink due to moisture absorption is reduced. Therefore, an ink with extremely stable performance can be obtained. However, the amount of water to adjust is 4% by weight
If it becomes larger, the dye or resin in the ink composition precipitates, and the outflow of the ink from the ballpoint pen tip is inhibited,
Writing blur and poor writing are likely to occur. On the other hand, if the amount of water to be adjusted is less than 1% by weight, the effect of alleviating moisture absorption is small, and the effect of suppressing the decrease in viscosity, which is the object of the present invention, cannot be exhibited.

[0016]

The present invention will be described below in detail with reference to examples. However, the present invention is not limited at all by this example.

Example 1 Spiron Black GMHsp (manufactured by Hodogaya Chemical Co., Ltd.) 15.0 parts by weight Spiron Violet C-RH (manufactured by Hodogaya Chemical Co., Ltd.) 15.0 Spiron Yellow C-2GH (Hodogaya Chemical (manufactured by Hodogaya Chemical Co., Ltd.) 10.0 benzyl alcohol 10.0 phenoxyethanol 31.9 oleic acid 3.0 Hilac # 111 (manufactured by Hitachi Chemical Co., Ltd.) 15.0 PVP K90 (manufactured by ISP Chemical) 0.1 After heating and stirring at 70 ° C. for 5 hours to dissolve, 1.2% by weight of water was added to adjust the water content, followed by filtration to obtain a black ink for a ballpoint pen.

Comparative Example 1 Spiron Black GMHsp (produced by Hodogaya Chemical Co., Ltd.) 15.0 parts by weight Spiron Violet C-RH (produced by Hodogaya Chemical Co., Ltd.) 15.0 Spiron Yellow C-2GH (Hodogaya Chemical ( 10.0) Benzyl alcohol 11.0 Phenoxyethanol 33.9 Oleic acid 3.0 Hilac # 111 (manufactured by Hitachi Chemical Co., Ltd.) 12.0 PVP K90 (manufactured by ISP Chemical) 0.1 After heating and stirring at 70 ° C. for 5 hours to dissolve, the mixture was filtered to obtain a black ink for a ballpoint pen.

Comparative Example 2 In Example 1, the water content was not adjusted.

The inks obtained in Example 1 and Comparative Examples 1 and 2 were filled in a polypropylene ink storage tube,
A ballpoint pen refill was created. Using these ballpoint pen refills, viscosity, moisture,
The preservability test was performed by measuring the dent, direct current and 5 ° C drawing line density, respectively. The measurement method is shown below, and the results are shown in Table 1.
Shown in

Viscosity: The value at 25 ° C. was measured using a cone plate type viscometer (manufactured by Tokimec). Measured value is Pa
-Expressed as s. Moisture: The ink collected from the ballpoint pen refill (made of plastic) was measured by a Karl Fischer moisture meter (manufactured by Hiranuma Sangyo Co., Ltd.). The measured value was expressed in% by weight. Botte: Judgment was made based on the state of ink dropping on drawing lines when writing was performed to 1000 m every 200 m using a mechanical writing tester. The worst value of 10 samples was adopted. ○ 0 to 2 spots. △ The number of drops is 3 or more. DC: The state of leakage of the ink when the ballpoint pen refill was stored for 7 days with the chip facing downward in an environment of a temperature of 25 ° C. and a humidity of 65% was determined. ○ There is no leakage of ink, or there is only slight leakage. △ An ink droplet is formed at the tip of the chip. 5 ° C drawing line density: The density of the writing line when writing in a room at 5 ° C was determined by comparing Example 1 with ○. ◎ indicates darker than ○. Δ indicates that it is not darker than ○.

[0022]

[Table 1]

Discussion of Table 1 As shown in Table 1, in Example 1 of the present invention in which the water content was adjusted, the change in the water content was slight when compared with the initial time and after 18 months. The change in viscosity is also slight. As a result, it can be seen that all of the results of the bow, direct current, and 5 ° C. line density were good. In Comparative Example 1 in which the initial viscosity was almost the same as that in Example 1 without adjusting the water content, the change in water content after 18 months was large, and the viscosity was low. Therefore, it can be seen that the line drawing density at 5 ° C. became dark after 18 months, but both the bow and the direct current became worse after 18 months. In Comparative Example 2 in which the water content was not adjusted in Example 1, the initial water content was low and the viscosity was high.
After about a month, the water and viscosity have reached substantially the same as in Example 1.
Therefore, both the bowing and the direct current showed good results, and the results were good even after 18 months of the 5 ° C drawing density, but the results were poor at the initial 5 ° C drawing density.

[0024]

By adding water to the oil-based ink for a ball-point pen in advance, even if the ball-point pen is stored for a long period of time, the viscosity of the ink hardly decreases due to moisture absorption. Therefore, the ink drops during writing and the chip faces downward. Ink can be provided that is less likely to change in design quality such that ink leakage hardly occurs.

Claims (3)

[Claims] When the oil-based ink composition for a ball-point pen is left in an operating environment, the water-absorbing ink composition absorbs moisture in the air and determines the amount of the water when the equilibrium state is reached. An oil-based ink composition for a ball-point pen, which is contained in a composition. 2. A method according to claim 1, wherein the water content is 1 to 4 with respect to the total amount of the ink.
The oil-based ink composition for a ball-point pen according to claim 1, wherein the composition is a weight percentage. 3. The oil-based ink composition for a ball-point pen according to claim 1, comprising at least a colorant, an organic solvent and a resin.