JP3078172B2 - Oil-based ink composition for ballpoint pens - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an oil-based ink composition for a ballpoint pen. More particularly, the present invention relates to an ink composition for an oil-based ballpoint pen having the advantages of an aqueous ballpoint pen.

[0002]

2. Description of the Related Art As ink for ballpoint pens, an aqueous ballpoint pen ink having a viscosity of 10 centipoise or less using water or a water-soluble solvent as a solvent and an oily solvent such as mineral oil, polyhydric alcohol, fatty acid, cellosolve and the like are used. Viscosity 1
Oil-based ballpoint pen inks of 2,000 to 20,000 centipoise are common.

[0003] In an oil-based ballpoint pen using ink for an oil-based ballpoint pen, ink supplied from a small-diameter ink storage tube and attached to the ball is transferred to the paper surface by rotation of the ball, and the transferred amount of ink is again transferred from the storage tube. It is a structure that is supplied to the ball.

A water-based ball-point pen using the water-based ball-point pen ink has a structure in which the water-based ball-point pen ink is supplied to a ball surface or a paper surface by the capillary action of a relay induction core made up of fine fibers.

Water-based inks for ballpoint pens and oil-based inks for ballpoint pens each have excellent advantages, but have various disadvantages. For example, an aqueous ballpoint pen has a low viscosity of the ink, and therefore, the ink supply to the pen tip utilizes a capillary action. Therefore, the characteristic feature of the water-based ball-point pen is that when the tip comes into contact with the paper, a capillary action acts on the contact point to supply the ink and light writing.
On the other hand, an ink relay guide core is required, which not only increases the amount of components but also has a difficulty in detecting the remaining amount of ink.

On the other hand, oil-based ballpoint pens have a simple structure because ink can be stored directly in a small-diameter ink storage tube due to the high viscosity of the ink, and the ink remaining amount can be reduced by using a transparent material for the ink storage tube. And that the ink transferred to the paper does not bleed. On the other hand, there is a disadvantage that the touch at the time of writing is heavy due to the high viscosity of the ink.

[0007]

SUMMARY OF THE INVENTION In view of the above-mentioned problems, an object of the present invention is to provide an oil-based ballpoint pen capable of storing ink directly in an ink storage tube and detecting the remaining amount of ink. An object of the present invention is to provide an ink composition for an oil-based ball-point pen having a light writing taste comparable to an aqueous ball-point pen.

[0008]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to achieve the above-mentioned object, and as a result, it is possible to solve the problem by blending a fatty acid amide wax with a coloring ink composed of an oily solvent. This led to the completion of the present invention.

That is, the present invention is an oil-based ballpoint pen ink composition containing at least one organic solvent selected from the group consisting of alcohols and glycol ethers, a fatty acid amide wax in the form of paste, and a coloring agent.

[0010] The organic solvent used in the composition of the present invention is at least one selected from the group consisting of alcohols and glycol ethers. Examples of the alcohols include high-boiling alcohols such as benzyl alcohol and phenoxyethanol, and polyhydric alcohols such as ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, trimethylene glycol, and glycerin. Examples of glycol ethers include diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, dipropylene glycol monobutyl ether, and tripropylene glycol monomethyl ether. These solvents are for ensuring basic performance as a ballpoint pen ink, and are necessary not only for dissolving or dispersing the colorant, but also for obtaining appropriate drying properties of drawn lines.

The coloring agent in the composition of the present invention includes:
All known dyes and pigments used in conventional ballpoint pen inks can be used. The dye may be a basic dye, an acid dye, a direct dye, or a solubilized or microencapsulated dye. For example, Varifast Black # 1802, # 1805, # 38
20, Varifast Violet # 1701, Varifast Yellow AUM, # 3104, Spiron Violet C-GNH, Spiron Orange GRH, Spiron Red BEH, Auramine, Rhodamine, Methyl Violet, Malachite Green, Crystal Violet,
Victoria Blue BOH and the like.

For example, as oil-soluble dyes, dyes soluble in the solvent used, for example, Varifast Color (trade name, manufactured by Orient Chemical Co., Ltd.), Aizen spiron dye, Aizen SOT dye [Hodogaya Chemical Co., Ltd.] (Registered trademark). As the pigment, an inorganic pigment or an organic pigment may be used as it is, or a processed pigment or a dispersed toner whose surface has been modified with a resin or a surfactant may be used. For example, as pigments, titanium oxide, carbon black, inorganic pigments such as metal powder, or azo lake, insoluble azo pigment, chelate azo pigment,
Organic pigments such as phthalocyanine pigments, perylene and perylene pigments, anthraquinone pigments, quinacridone pigments, dye lakes, nitro pigments, and nitroso pigments.

These colorants may be used alone or in combination of two or more. The content of the coloring agent is not particularly limited, and may be an amount depending on the solubility or dispersing power of the coloring agent or an amount suitable for a desired hue or concentration. However, if the content is too large, the writing performance is poor. In the case of a small amount, there is no problem in writing performance, but there is a drawback that coloring of drawing lines as a ballpoint pen is deteriorated.

The ink composition of the present invention may contain, if necessary, auxiliaries commonly used in oil-based ink compositions such as resins, preservatives and rust inhibitors. For example, as the resin, a resin commonly used in an ordinary oil-based ballpoint pen ink composition, for example, a ketone resin, a sulfamide resin, a maleic resin, an ester gum, a xylene resin, an alkyd resin, a phenol resin, a rosin, and polyvinylpyrrolidone are used. Can be These resins may be used alone or in combination of two or more, and the content thereof is 0.1 to 40% by weight based on the total amount of the ink composition.
Range. These resins have the effect of adjusting the viscosity of the ink composition and improving the fixability, water resistance and dispersion stability of the colorant.

The fatty acid amide wax used in the ink composition of the present invention is a typical organic thixotropic agent, and can be used in a wide range from non-polar solvents to medium-polar solvents. There are two types of shapes, a powder and a paste, and a powder requires a heating step for forming a swollen gel structure, whereas a paste does not require a heating step. The fatty acid amide wax used in the present invention may be any of powdery pastes. The content of the fatty acid amide wax in the composition is 0.5 to 3.0% by weight. If the content exceeds 3.0% by weight, writing becomes poor,
If the amount is less than 0.5% by weight, ink leaks, which is not preferable.

[0016]

In the ink composition for an oil-based ballpoint pen of the present invention, it is considered that the fatty acid amide wax is colloidally dispersed in the ink composition to form a strong network structure, and thixotropy is imparted by the action. Therefore, the ink that shows a large apparent viscosity in the ink storage tube,
The rotation of the ball during writing increases the shear rate near the ball, decreases the apparent viscosity, and increases the fluidity at the pen tip. Therefore, ink can be stored directly in the small-diameter ink storage tube without causing ink leakage, and a light touch like a water-based ball-point pen can be obtained when writing.

[0017]

Next, the present invention will be described in more detail by way of examples. The present invention is not limited by this embodiment. (Parts) in Examples and Comparative Examples indicates parts by weight. The ink compositions obtained in the examples and comparative examples were filled in ink storage tubes made of polypropylene tubes having an inner diameter of 2 mm. The following test was performed using a ballpoint pen equipped with this ink storage tube and a stainless steel tip. (A) Ink leakage test: The pen tip was left down for 3 days in a constant temperature / humidity bath at 25 ° C. and 65% RH to check for ink leakage. Those that did not cause ink leakage were evaluated as ○, and those that caused ink were evaluated as x. (B) Writing taste test: Hand-written sensory evaluation. (C) Line drawing state: Line drawing by mechanical writing was evaluated. Table 1 shows the evaluation results.

(Example 1) Carbon black 15 (parts) polyvinyl butyral 3 benzyl alcohol 15 diethylene glycol monobutyl ether 66 tallen BA-600 (trade name of fatty acid amide wax) 1 〃

(Example 2) Carbon black 15 (parts) polyvinyl butyral 3 {benzyl alcohol 15} tripropylene glycol monomethyl ether 64.2 {tarene BA-600 (trade name of fatty acid amide wax) 2.8}

(Example 3) Carbon black 15 (parts) polyvinyl butyral 3 {benzyl alcohol 15} tripropylene glycol monomethyl ether 66.5 {tarene BA-600 (trade name of fatty acid amide wax) 0.5}

(Comparative Example 1) Carbon black 15 parts Polyvinyl butyral 3 Benzyl alcohol 15 Diethylene glycol monobutyl ether 67

(Comparative Example 2) Carbon black 15 (parts) polyvinyl butyral 3 {benzyl alcohol 15} tripropylene glycol monomethyl ether 66.7 {tarene BA-600 (trade name of fatty acid amide wax) 0.3}

(Comparative Example 3) Carbon black 15 (parts) polyvinyl butyral 3 {benzyl alcohol 15} tripropylene glycol monomethyl ether 63.5 {tarene BA-600 (trade name of fatty acid amide wax) 3.5}

[0024]

[Table 1]

[0025]

The oil-based ink for a ballpoint pen of the present invention does not cause ink leakage even when the pen tip is left down while maintaining a light writing taste and good drawing line like the ink for a water-based ballpoint pen. Moreover, there is no need to use a relay guide core as in the case of a water-based ballpoint pen, and it is easy to detect the remaining amount of ink.

Claims (2)

(57) [Claims] At least one organic solvent selected from the group consisting of alcohols and glycol ethers,
An ink composition for an oil-based ballpoint pen, comprising a paste-like fatty acid amide wax and a coloring agent. 2. A paste-like fatty acid amide wax is blended in an amount of 0.5 to 3.0% by weight and dispersed without heating.
The oil-based ink composition for a ball-point pen according to claim 1, comprising: