JP3258129B2 - Oil-based ballpoint pen - 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 for a ballpoint pen and a ballpoint pen using the same.

[0002]

2. Description of the Related Art A ball-point pen comprises a ball, a pen tip including a chip holder, an ink storage tube, a pen shaft, and the like. In writing with a ballpoint pen, ink flowing from inside the chip is transferred or penetrated into a recording medium such as paper by rotation of the ball of the pen point, and handwriting and drawing are created by the transfer. At that time, excess ink that could not be transferred or penetrated adhered to the outer periphery of the chip holder,
At the beginning or sometimes at the time of writing, a so-called bottling phenomenon occurs in which a lump of ink is dropped during writing, and a clear drawing line may not be obtained.

[0003] Aqueous ballpoint pens have a low viscosity of several mPa · S or less, and therefore have the advantage that they can be written with a light writing pressure and have a good writing quality. However, there is a drawback that the direct current phenomenon in which the ink flows gently from the pen tip and the reverse flow phenomenon in which the air flows in from the tip of the ballpoint pen and the ink flows out easily occur. Therefore, a method for preventing these phenomena has been adopted. In addition, there is also a problem that if the solvent is removed, the vapor pressure is high, and if left in a cap-off state, the tip is dried, the ink does not flow out, and writing cannot be performed.

On the other hand, oil-based ballpoint pens have a high viscosity of several thousand mPa · S or more, and therefore have poor writing characteristics due to high resistance when the ball rotates when the ink flows out of the pen tip. There are drawbacks.

Recently, ballpoint pens for medium-viscosity inks using inks in the intermediate viscosity region between the above-mentioned aqueous and oily properties (several mPa · S to several thousand mPa · S) have been developed. However, the above-mentioned writing taste, DC phenomenon, boss phenomenon, cap-off performance, pen structure, and the like are interrelated, and an oil-based ballpoint pen for medium viscosity has not been obtained.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to develop an oil-based ballpoint pen for medium viscosity. That is, it is an object of the present invention to provide a ball-point pen having no capping phenomenon, no DC phenomenon, and excellent cap-off performance and writing quality, and a ball-point pen ink used therefor.

[0007]

Means for Solving the Problems As a result of repeated studies to achieve the above object, the present inventor has found that by using a solvent having a vapor pressure of a specific condition or less and adjusting the viscosity under a specific shear rate, The inventors have found that the above-mentioned oil-based ballpoint pen ink is obtained, and have completed the present invention.

[0008] The oil-based ballpoint pen ink of the present invention is an oil-based ballpoint ink containing at least a colorant, a solvent, a resin and a thickener, wherein the solvent has a vapor pressure of 0.1 mmHg.
(20 ° C.) or less organic solvent is contained in an amount of 60% by weight or more based on the total amount of the ink, and the viscosity of the ink is 100 mPa · s or less at a shear rate of 400 s ⁻¹ and 1000 mPa · s or more at a shear rate of 5 s ⁻¹ . It is characterized by the following.

The ballpoint pen of the present invention is characterized by being filled with the oil-based ballpoint pen ink of the present invention.

[0010] The solvent used in the oil-based ballpoint pen ink of the present invention contains, as a main solvent, an organic solvent having a vapor pressure of 0.1 mmHg (20 ° C) or less based on the total amount of the ink, preferably 60% by weight or more, more preferably 70% by weight or more. Must be contained at 80% or more. The main solvent has a vapor pressure of 0.1 mmHg (2
0 ° C.) or higher, the drying property of the solvent is fast, the ink solidifies at the pen tip, and the cap-off performance and the like are significantly reduced.
Not preferred.

As the organic solvent having a vapor pressure of 0.1 mmHg (20 ° C.) or less, specifically, benzyl alcohol (1 mmHg /
58 ° C), dipropylene glycol (0.01 mmHg or less / 20 ° C, water-soluble), diethylene glycol monoethyl ether (0.3 mmHg / 25 ° C), prolene glycol monophenyl ether (0.01 mmHg or less / 20 ° C), ethylene glycol Monobutyl ether (0.852mmHg
/ 25 ° C), triethylene glycol monobutyl ether (0.01 mmHg or less / 20 ° C), and tripropylene glycol monomethyl ether (0.03 mmHg / 20 ° C). Octyl adipate (0.00
1 mmHg / 85 ° C), dibutyl sebacate (0.001 mm
Hg / 71 ° C), dioctyl sebacate (5 mmHg / 240
C), glycerin (0.0025 mmHg / 50 ° C), polypropylene glycol (molecular weight 400 to 700), glycerin derivative (for example, polyoxypropyltriol,
"Uniol TG-1000" and "Uniol TG-2000" manufactured by NOF Corporation.

Further, ethylene glycol monophenyl ether (0.03 mmHg / 20 ° C.), ethylene glycol monobenzyl ether (0.02 mmHg / 20 ° C.), ethylene glycol mono α-methylbenzyl ether (0.02 mmHg / 20 ° C.), Ethylene glycol mono α
α 'dimethyl benzyl ether (0.02 mmHg / 20
° C), ethylene glycol monomethylphenyl ether isomer mixture (0.02 mmHg), ethylene glycol monodimethylphenyl ether isomer mixture (0.02 mmHg)
Hg / 20 ° C), ethylene glycol monoethylphenyl ether isomer mixture (0.02 mmHg / 20 ° C), ethylene glycol monomethylbenzyl ether isomer mixture (0.02 mmHg / 20 ° C), ethylene glycol monoethylbenzyl ether isomer mixture (0.02mmHg /
20 ° C), ethylene glycol monocyclohexyl ether (0.01 mmHg / 20 ° C), ethylene glycol monomenthyl ether (0.02 mmHg / 20 ° C), ethylene glycol monodihydro α-tervinyl ether (0.02 mmHg / 20 ° C), propylene Glycol monophenyl ether (0.03 mmHg / 20 ° C), propylene glycol monobenzyl ether (0.03 mmHg / 2
0 ° C), propylene glycol monocyclohexyl ether (0.04 mmHg / 20 ° C), propylene glycol monotervinyl ether (0.02 mmHg / 20 ° C),

Diethylene glycol monophenyl ether (0.02 mmHg / 20 ° C.), diethylene glycol monobenzyl phenyl ether (0.02 mmHg / 20 ° C.)
° C), diethylene glycol monoethyl phenyl ether (0.02 mmHg or less / 20 ° C), ethylene gray monoethylbenzyl ether (0.02 mmHg or less / 20 ° C)
° C), diethylene glycol monocyclohexyl ether (0.02 mmHg / 20 ° C), diethylene glycol monomenthyl ether (0.02 mmHg / 20 ° C), diethylene glycol monodihydro α-tervinyl ether (0.02 mmHg / 20 ° C), dipropylene glycol monophenyl Ether (0.02 mmHg / 20 ° C), dipropylene glycol monobenzyl ether (0.02 mmHg
/ 20 ° C.), dipropylene glycol monocyclohexyl ether (0.03 mmHg / 20 ° C.), dipropylene glycol monotervinyl ether (0.02 mmHg / 20
° C). These main solvents are used in an amount of 60 to 95% by weight in the ink. If the content is less than 60% by weight, the cap-off performance deteriorates, which is not preferable.

The ink for a ballpoint pen according to the present invention must have a viscosity of 100 mPa · S or less at a shear rate of 400 s ⁻¹ . The reason for this is based on the result that the present inventor has repeatedly studied the viscosity at that time, paying attention to the fact that the shear force is applied to the ink by the rotation of the ball at the time of writing and the shear rate is usually 400 s ^-1 or more. . That is, the viscosity at a shear rate of 400 s ⁻¹ is related to the penetration of the ink into a writing object such as paper and the occurrence of a bottling phenomenon.
In the case of a viscosity of 00 mPa · S or less, no
When it exceeds 00 mPa · S, the bottling phenomenon increases. Further, the ink for a ballpoint pen according to the present invention needs to have a viscosity at a shear rate of 5 s ^-1 of at least 1,000 mPa · S.
The reason for this is based on the inventor's idea that the DC phenomenon relates to the viscosity at rest or infinitely near the shear rate of ^{0 s -1} . Actually measurable 10s
^-1 based on the study of the phenomenon at a viscosity of 1000
Above mPa · S, there is no DC phenomenon, and below 1000 mPa · S, a DC phenomenon occurs.

As the colorant used in the oil-based ballpoint pen ink of the present invention, dyes and pigments usually used for writing implements and paint inks can be used. As a dye,
Basic dyes, acid dyes, direct dyes and the like may of course be those solubilized or microencapsulated. For example, Varifast Black # 1802, # 1805,
# 3820, Balifast Violet # 1701,
Varifast Yellow AUM, # 3104, Spiron Violet C-RH, Spiron Black CMHspe
Cial, Spiron Yellow C-GNH, Spiron Orange GRH, Spiron Red BEH, Auramine, Rhodamine, Methyl Violet, Malachite Green, Crystal Violet, Victoria Blue BOH and the like. Further, 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. Examples include titanium oxide, carbon black, phthalocyanine-based, azo-based, anthraquinone-based, quinacridone-based, microlease color (manufactured by Ciba Geigy), and Fuji AS color (manufactured by Fuji Dye Co., Ltd.). The amount of addition is not particularly limited, and may be any amount depending on the solubility or dispersing power of the colorant or an amount suitable for a desired hue or concentration. If the amount of addition is too large, the effect is reduced even with the composition of the ink of the present invention, and if the amount is too small, blurring and inability to write are extremely reduced, but the coloring of the drawing line as a ballpoint pen is inferior, and usually 1 to 40% by weight. Used in the range.

The oil-based ballpoint pen ink of the present invention is not limited to the above-mentioned coloring agents and solvents, but also includes resins, thickeners, and additives such as preservatives, rust preventives, and lubricants. Choose from the ingredients and mix.

For example, as the resin, a resin commonly used in ordinary oil-based ballpoint pen inks, for example, ketone resin, sulfamide resin, maleic acid resin, ester gum, xylene resin, alkyd resin, phenol resin,
Rosin, polyvinylpyrrolidone and the like are used. These resins may be used alone or as a mixture of two or more kinds. The compounding amount is in the range of 0.1 to 20.0% by weight based on the total amount of the ink composition. These resins act to improve the water resistance and sticking properties of the drawn lines and to adjust the viscosity.

Examples of the thickener include "Benton SD-2" and "Benton 27" manufactured by NL Chemicals Co., Ltd., "TIXOGEL VZ" and "TIXOG" manufactured by Nissan Gardler Catalysts.
Organic bentonite such as "ELEZ", "EX-0101" manufactured by SUD Chemical, "Aerosil 3" manufactured by Nippon Aerosil Co., Ltd.
80 "," Aerosil COK84 ", silica such as" Mizukasil P-801 "manufactured by Mizusawa Chemical," Tallen VA-100 "," VA-500 "manufactured by Kyoeisha Yushi Kagaku Kogyo.
“VA-800”, “ASA T-1” manufactured by Ito Oil,
"ASA T-51", "ASA T-350F", and other fatty acid polyamides are added.

The ballpoint pen of the present invention comprises a ball, a pen tip comprising a tip holder, an ink storage tube, a joint connecting the chip and the storage tube, a pen shaft, and the like. It is filled with ink.

It is considered that the oil-based ink for a ball-point pen of the present invention has an effect of preventing a direct current phenomenon and a warping phenomenon due to the relationship between the ink viscosity and the evaporation rate of the solvent.
In general, the higher the viscosity, the slower the outflow speed, and the faster the evaporation speed of the solvent, the more rapidly the viscosity near the ball rises, and the less direct current occurs. On the other hand, if the speed is too high, the pen point will immediately have poor writing. The present invention solves this problem by adjusting the vapor pressure of the solvent and the viscosity of the ink at a specific shear rate.

[0021]

The present invention will be described in more detail with reference to examples. An ink evaluation test was performed as follows. Also,
The ballpoint pen used for the test was a polypropylene tube with an inner diameter of 2.0 mm, a stainless steel tip (the ball was a cemented carbide,
0.7 mm in diameter). This ballpoint pen was filled with the inks obtained in Examples and Comparative Examples, and the following tests were performed.

Viscosity: Measured at 25 ° C. by a double cylinder method using a rheometer. Prevention of bottling phenomenon: After filling a predetermined ink into a ballpoint pen, the speed was 4.5 m / min and the angle was 6 with a mechanical writing tester.
After writing under the conditions of 0 ° and a load of 200 g, the amount of ink adhering to the chip holder was observed, and evaluation was made as ◎ for almost none, ○ for a little, Δ for a little, and X for a very large one. did. DC prevention property: 30 ballpoint pens filled with a predetermined ink are left in a thermostat at a temperature of 50 ° C. and a humidity of 80% for 3 days with the pen point down, and then the viscosity of the DC phenomenon is examined, and there is almost no viscosity. The results were evaluated as ◎, slightly present as 、, slightly higher as Δ, and extremely high as ×.

Writability: The feeling of writing in freehand writing with a ballpoint pen filled with a predetermined ink is responsively compared with each other. Very light writing is indicated by ◎, light writing is indicated by ○, and slightly heavy writing is evaluated. △, heavy writing was rated as ×. Cap-off property: The length of the initial drawing line when writing with a ball-point pen filled with a predetermined ink was measured for 90 days in a constant-temperature bath at a temperature of 25 ° C. and a humidity of 60% with the one immediately after the ball-point pen was filled with the ink. Compare it to the one you left
At the beginning of writing, the burrs at the beginning of the writing were judged as 0 mm, ◎ as 5 mm or less, Δ as 5-30 mm, and X as 30 mm or more.

Examples 1 to 3 and Comparative Examples 1 to 3 Oil-based ballpoint pen inks were prepared according to the formulations shown in Table 1. Table 1 shows the test results with a predetermined ball-point pen filled with this ink. The black pigment in the composition is “Varifast Black # 3820” (manufactured by Orient Chemical Industry), the yellow pigment is “Varifast Yellow AUN” (manufactured by Orient Chemical Industry), and the carbon black is “Carbon Black MA-
100 "(manufactured by Mitsubishi Kasei Corporation), silica was" Aerosil COK84 "(manufactured by Nippon Aerosil), and organic bentonite was" EX-0101 "(SUD).
ASAT-350F (Ito Oil Co., Ltd.) was used as the chemical amide and fatty acid amide. As the polyvinyl butyral, "ESREC B BL-1" (manufactured by Sekisui Chemical Co., Ltd.) was used. Polyvinylpyrrolidone can be obtained from "Rubiscol K-30" (B
ASF).

[0025]

[Table 1]

According to the present invention, since the bottling phenomenon and the direct current phenomenon do not occur, a clear drawing line can be drawn without transferring the ink mass at the beginning of writing, and the writing quality during writing becomes extremely good. An oil-based ballpoint pen ink and a ballpoint pen using the same are provided.

Continuation of front page (58) Field surveyed (Int.Cl. ⁷ , DB name) C09D 11/00-11/20

Claims (2)

(57) [Claims] 1. An oil-based ballpoint pen ink containing at least a colorant, a solvent, a resin, and a thickener, wherein an organic solvent having a vapor pressure of 0.1 mmHg (20 ° C.) or less is contained in the solvent in an amount of 60% by weight based on the total amount of the ink. An oil-based ballpoint pen ink containing the above, wherein the viscosity of the ink is 100 mPa · s or less at a shear rate of 400 s ⁻¹ and 1000 mPa · s or more at a shear rate of 5 s ⁻¹ . 2. A ballpoint pen which is filled with the oil-based ballpoint pen ink according to claim 1.