JPH0948941A - Oil-base ballpoint ink and ballpoint pen - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an oil-base ballpoint ink which does not undergo any degradation in writing performance even when a ballpoint pen contg. the ink is left uncapped by selecting an oil-base ballpoint ink contg. a specific org. solvent, a colorant, and a flocculant and having a specified viscosity. SOLUTION: This ink contains an org. solvent having a vapor pressure of 0.2mmHg or lower at 20 deg.C, a colorant, and a flocculant and has a non- Newtonian viscosity index of 0.2-0.5 and a viscosity of 200mPa.s or lower at 25 deg.C and 50rpm. Examples of the solvent are benzyl alcohol, dipropylene glycol, propylene glycol monophenyl ether, triethylene glycol monobutyl ether, and tripropylene glycol monomethyl ether.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink for a ballpoint pen and a direct storage type ballpoint pen using the ink.

[0002]

2. Description of the Related Art In conventional oil-based ballpoint pens, the ink is mainly composed of a solvent with a low vapor pressure, and even if the pen tip is exposed and the pen tip is exposed, it is hard to cause scratches and writing inability. Since it has a high viscosity of 10,000 mPa · s, it requires a high writing pressure and is heavy to write, and it has the drawback that fingers, arms, shoulders, etc. tend to get tired after long-time writing. On the other hand, water-based ballpoint pens have a low ink viscosity and thus have a light writing feel, but the main solvent is water that easily evaporates. Therefore, if the cap is removed and the pen tip is exposed, scratches and inability to write will occur. There is. Also, when writing ink, if the ink that has flowed out of the pen tip cannot be transferred or penetrated, it is possible to prevent the so-called batter phenomenon where the ink sticks near the tip holder and stains the tip of the pen and the paper surface. Is the subject of. JP-A 1-299880 discloses an oil-based ball-point pen ink which has the characteristics of both an oil-based ink having an ink viscosity of 50 to 2000 centipoise (25 ° C.) and a water-based ink, in which the surface tension of an organic solvent is regulated. Not kimono. Recently, medium-viscosity water-based inks have entered the market as having many advantages in terms of quality and economy, but the cap-off performance is less likely to cause writing inability even when the cap is removed like oil-based inks. Is not satisfied.

[0003]

SUMMARY OF THE INVENTION The present invention is to solve the above-mentioned problems, and the characteristics of the oil-based ink having excellent so-called cap-off performance and low writing brush which do not deteriorate the writing performance even if the cap is removed and left to stand. It is an object of the present invention to provide an oil-based ballpoint pen ink having the characteristics of a water-based ink that does not cause bloating under pressure.

[0004]

The oil-based ballpoint pen ink of the present invention has the following constitutions (1) to (3). (1) It contains an organic solvent having a vapor pressure of 0.2 mmHg (20 ° C.) or less, a colorant, and an aggregating agent, and has a content of 0.2 to 0.
Non-Newtonian viscosity index of 5, 200 mPa · s (25 ℃, 5
An oil-based ballpoint pen ink having a viscosity of 0 rpm or less. (2) (a) Containing an organic solvent having a vapor pressure of 0.2 mmHg (20 ° C.) or less, a pigment dispersant and, if necessary, an oleophobic additive, and providing high surface free energy of stainless steel, bronze, etc. A non-Newtonian viscosity index of 0.2 to 0.5, including a self-lyophobic vehicle having a contact angle with the surface of the material of 5 to 40 °; (b) a flocculant; and (c) a pigment, 200 mPa · s ( An oil-based ballpoint pen ink having a viscosity of 25 ° C., 50 rpm or less. (3) (a ′) Containing an organic solvent having a vapor pressure of 0.2 mmHg (20 ° C.) or less, a dye and optionally an oleophobic additive, and having high surface free energy of stainless steel, bronze, etc. The contact angle with the surface of the material is 5
A self-lyophobic vehicle of -40 °; and (b) a non-Newtonian viscosity index of 0.2-0.5 with a flocculant, 20.
An oil-based ballpoint pen ink having a viscosity of 0 mPa · s (25 ° C, 50 rpm) or less.

The oil-based ballpoint pen of the present invention is
It is composed of (4) to (6). (4) A direct-drain type oil-based ballpoint pen having a pen tip composed of a ball and a tip holder and an ink containing tube, containing an organic solvent having a vapor pressure of 0.2 mmHg (20 ° C.) or less, a colorant and a coagulant. An oil-based ballpoint pen comprising an ink containing tube filled with an ink having a non-Newtonian viscosity index of 0.2 to 0.5 and a viscosity of 200 mPa · s (25 ° C., 50 rpm) or less. (5) In a direct reservoir type oil-based ballpoint pen having a pen tip composed of a ball and a tip holder, and an ink containing tube,
(A) A material containing an organic solvent having a vapor pressure of 0.2 mmHg (20 ° C.) or less, a pigment dispersant and, if necessary, an oleophobic additive, and having high surface free energy such as stainless steel and bronze. Contact angle of 5 to surface
Self-lyophobic vehicle at 40 °; (b) flocculant; and (c) non-Newtonian viscosity index of 0.2-0.5 with pigment, viscosity less than 200 mPa · s (25 ° C., 50 rpm) An oil-based ballpoint pen comprising an ink containing tube filled with ink. (6) In a direct-drain type oil-based ballpoint pen having a pen tip composed of a ball and a tip holder, and an ink containing tube,
(A ') Surface of a material having a high surface free energy such as stainless steel and bronze, which contains an organic solvent having a vapor pressure of 0.2 mmHg (20 ° C.) or less, a dye and optionally an oleophobic additive. Contact angle to 5-40
A non-Newtonian viscosity index of 0.2-0.5, including a self-lyophobic vehicle, which is °;
An oil-based ballpoint pen comprising an ink containing tube filled with an ink having a viscosity of s (25 ° C., 50 rpm) or less.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION The organic solvent used in the oil-based ballpoint pen ink of the present invention is an organic solvent of 0.2 mmHg (20 ° C.) or less, specifically, benzyl alcohol (1 mmHg /
58 ° C), dipropylene glycol (0.01 mmHg or less / 20 ° C, water soluble), prolene glycol monophenyl ether (0.01 mmHg or less / 20 ° C), triethylene glycol monobutyl ether (0.01 mmHg or less / 20
C.), tripropylene glycol monomethyl ether (0.03 mmHg / 20.degree. C.) and the like. Also, octyl adipate (0.001 mmHg / 85 ° C), dibutyl sebacate (0.001 mmHg / 71 ° C), dioctyl sebacate (5 mmHg / 240 ° C), glycerin (0.0
(025 mmHg / 50 ° C.), propylene glycol (molecular weight 400 to 700), glycerin derivatives (for example, polyoxypropyltriol, “Uniol TG-1000”, “Uniol TG-2000” manufactured by NOF CORPORATION) and the like.

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'Dimethylbenzyl ether (0.02mmHg / 20
℃), ethylene glycol monomethyl phenyl ether isomer mixture (0.02 mmHg), ethylene glycol monodimethyl phenyl ether isomer mixture (0.02 mm
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 ℃), ethylene glycol monocyclohexyl ether (0.01mmHg / 20 ℃), ethylene glycol monodihydro α-tervinyl ether (0.02mmHg / 2
0 ° C), propylene glycol monophenyl ether (0.03mmHg / 20 ° C), propylene glycol monobenzyl ether (0.03mmHg / 20 ° C), propylene glycol monocyclohexyl ether (0.04mm
Hg / 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)
℃), diethylene glycol monoethyl phenyl ether (0.02 mmHg or less / 20 ℃), ethylene glycol monoethyl benzyl ether (0.02 mmHg or less / 20
℃), diethylene glycol monocyclohexyl ether (0.02mmHg / 20 ℃), diethylene glycol monomethyl ether (0.18mmHg / 25 ℃), diethylene glycol monodihydro α-tervinyl ether (0.02mmHg / 20 ℃), dipropylene glycol monophenyl ether (0.02mmHg / 20 ℃), dipropylene glycol monobenzyl ether (0.02mmHg
/ 20 ° C), dipropylene glycol monocyclohexyl ether (0.03 mmHg / 20 ° C), dipropylene glycol monotervinyl ether (0.02 mmHg / 20
℃) and the like. The amount of these solvents used is 50 to 95% by weight in the ink. If it is less than 50% by weight, the cap-off performance is deteriorated, which is not preferable.

The self-lyophobic vehicle used in the ink of the present invention comprises (a) an organic solvent having a vapor pressure of 0.2 mmHg or less, a pigment dispersant and, if necessary, an oleophobic additive. And a vehicle having a contact angle of 5 to 40 ° with respect to the surface of a material having a high surface free energy such as stainless steel or bronze, or (a ') an organic solvent having a vapor pressure of 0.2 mmHg or less, a dye and, if necessary, It is a vehicle that contains an oleophobic additive and has a contact angle of 5 to 40 with respect to the surface of a material having a high surface free energy such as stainless steel and bronze.
Resins, rust preventives, lubricating oils, etc. can be added to these vehicles to the extent that the self-lyophobic property is not impaired.

A vehicle having a self-lyophobic property hardly wets the chip holder and makes it difficult to form ink droplets which cause a ghost phenomenon. In other words, in order to prevent the battering phenomenon, the vehicle should in principle have a numerical value close to a contact angle of 180 °, but in reality it is preferably 40 ° or less. The reason is that the organic solvent used in the ink originally has a small surface tension γ _L and therefore has a small difference from the critical surface tension γ _C , so that a large contact angle (θ) such as 180 ° cannot be obtained. This is because a large value such as a contact angle of 180 ° is not preferable in consideration of the original writability of the ink. A contact angle of 5 ° or less is not preferable because a ghost phenomenon occurs regardless of the ink viscosity described later.

The self-lyophobic vehicle is a solid low-energy surface that is adsorbed at the solid / liquid interface when each molecule or a certain molecule of the constituent component comes into contact with the high-energy surface to lower the critical surface tension of the solid to form a low-energy surface. Does not spread on the surface, making it difficult to wet. The self-lyophobic solvent is when the critical surface tension γ _c of the adsorbed film of the solvent molecule itself is smaller than the surface tension of the solvent, but even if the solvent itself does not have self-lyophobic property, adsorption of solute molecules dissolved in the solvent When the monolayer γ _c is smaller than the surface tension γ _{lv of} the solution, lyophobic property is obtained. Such solute molecules are oleophobic additives.
Is called an oleophobic monolayer (ol
eophobic monolayer). In this way, the mechanism for expressing self-lyophobicity is constituted by an oleophobic solvent or by a non-oleophobic solvent and an oleophobic additive, but the resin necessary for the ink, a rust preventive agent, within a range that does not destroy the mechanism. Lubricating oil may be added. It is also possible to adjust the surface tension by adding a surfactant to control the self-lyophobic property.

Examples of the oleophobic additive include perfluoroalkyl phosphate ester and alkyl phosphate ester. However, since the effects of these differ depending on the interaction such as solubility with a solvent, selection of the oleophobic additive is limited depending on the type of the solvent. For example, the solvent is polypropylene glycol (average molecular weight 4
00) or tripropylene glycol monobutyl ether, perfluoroalkyl phosphate ester is preferable, and in ethylene glycol monophenyl ether solvent, alkyl phosphate ester is effective as an oleophobic additive. As an oleophobic additive, the surface tension of liquid is 24dyne
/ Cm or less, fluorocarbon and silicone oil,
When it exceeds 24 dyne / cm, fatty acids and other aliphatic polar compounds are effective respectively. If the surface tension of the liquid is 30 to 32 dyne / cm, a polar compound which is a derivative of branched or cyclic hydrocarbon can be used. These can be controlled as required by the viscosity of the vehicle, the surface tension and the like.

As the colorant used in the ink for the ballpoint pen of the present invention, it is possible to use dyes and pigments which are usually used in writing instruments and paint inks. Dyes are one component of the vehicle, but pigments are not. The dye may be a basic dye, an acid dye, a direct dye or the like, and may be a solubilized or microencapsulated dye. For example, "Varifast Black # 1802",
"Same # 1805", "Same # 3820", "Varifast Violet # 1701", "Varifast Yellow A"
UM ”,“ Same # 3104 ”[above Orient Chemical Industry
Co., Ltd.], "Spiron Violet C-RH", "Spiron Black CMHspecial", "Spiron Yellow C-GNH", "Spiron Orange GRH", "Spiron Red BEH" [above Hodogaya Chemical Co., Ltd.]
Made, auramine, rhodamine, methyl violet,
Examples include malachite green, crystal violet, and Victoria blue BOH. 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 is modified with a resin or a surfactant may be used. For example, titanium oxide, carbon black, phthalocyanine series, azo series, anthraquinone series,
Examples include quinacridone type, micro lease color (manufactured by Ciba Geigy) and Fuji AS color (manufactured by Fuji Dye Co., Ltd.). The amount added is not particularly limited, and may be an amount depending on the solubility or dispersive power of the colorant or an amount suitable for a desired hue or concentration, but this amount may be a faint phenomenon of writing characters or drawn lines and poor writing property. It is deeply related, and if the addition amount is too large, the effect is reduced even with the composition of the ink of the present invention, and if it is a small amount, the blurring and the inability to write are extremely reduced, but the coloring of the line drawn as a ball-point pen is inferior, usually 0.5 to 50. Used in the range of wt%.

Examples of the pigment dispersant for the vehicle component include polyvinyl butyral, polyvinyl pyrrolidone, polyacrylic acid, styrene-maleic acid resins and other general pigment dispersing resins and oligomers. Specifically, ICI "Solspers" resin, oligomer, polyvinyl butyral "S-REC B" manufactured by Sekisui Chemical Co., Ltd.
BM-1 "and" ESREC BBL-1 "can be mentioned. Further, surfactants such as anions, nonions and cations may be added mainly or auxiliary.
The content is determined by the type of pigment and the shade of the ink color, and is 0.1 to 40% by weight based on the pigment.
It is in the range of 0.05 to 20% by weight with respect to the total amount of the ink.

As the aggregating agent used in the ink of the present invention,
As an inorganic system, synthetic finely divided silica, bentonite, ultrafine precipitated calcium carbonate, etc .; as a composite system, an organic compound obtained by treating bentonite with a cationic organic compound and exchanging inorganic cations and water of hydration existing between crystal layers Bentonite (modified clay), surface-treated calcium carbonate, etc .; as organic systems, metal soap, water-added castor oil, polyamide wax, benzylidene sorbitol, amide wax,
Microgel, polyethylene oxide, linseed polymerized oil, vegetable oil polymerized oil such as fatty acid dimer; sulfate ester type (sulfated oil, higher alcohol, sulfate), nonionic type (fatty acid ester type, polyether type) as surfactant And so on. Specific product names include "Benton SD-2" and "Benton 27" manufactured by NL Chemicals, and "TIXOGEL" manufactured by Nissan Gardler Catalyst Co., Ltd.
VZ "," TIXOGEL EZ "," E "made by SUD
Organic bentonite such as X-0101 ", Mizusawa Chemical Industry
"Mizukasil P-801" manufactured by Nippon Aerosil Co., Ltd., "Aerosil 380" manufactured by Nippon Aerosil Co., Ltd., "Aerosil COK8"
4 "silica type, Koeisha Yushi Kagaku Kogyo Co., Ltd." Tarlen VA-100 "," VA-500 "," VA-80 "
0 "," ASA T-1 "," T-5 "manufactured by Ito Oil Co., Ltd.
Examples thereof include fatty acid polyamides such as 1 "and" T-350F ". The content thereof is 0.01 to 10%, preferably 0.5 to 5%.

The ink of the present invention has a Newtonian viscosity index n of 0.2 to 0.5 (25 ° C.). This n is defined by the following flow equation: S = μD ⁿ [where S is the shear stress and D is the shear rate]. The shear thinning index n is preferably 0.2 to 0.
4. When n exceeds 0.5, a DC phenomenon occurs,
When it is less than 0.2, the writing property of the ink is poor, and blurring and writing failure occur.

The viscosity of the ink of the present invention is 200 mPa.s.
(25 ° C., 50 rpm) or less is required. It is preferably 100 mPa · s (25 ° C, 50 rpm) or less, more preferably 50 mPa · s (25 ° C, 50 rpm) or less. Self-lyophobicity and contact angle do not include a time factor, and therefore represent an equilibrium state. In principle, if the vehicle exhibits self-lyophobicity, the battering phenomenon should disappear. However, when the viscosity is high, the repelling speed of the droplets becomes slower and the self-lyophobic effect becomes less effective. In other words, the battering phenomenon is determined by both the self-lyophobic property (contact angle) of the vehicle and the viscosity of the ink. The viscosity is 200 mPa · s or less, and the battering phenomenon disappears when the contact angle is large, but the viscosity is 200 mPa · s. If the contact angle becomes smaller than the above range, the phenomenon of "battering" will occur.

The ballpoint pen of the present invention comprises a pen tip consisting of a ball and a tip holder, an ink containing tube, a joint connecting the tip and the containing tube, and the like, and the ink for a ballpoint pen of the present invention described above is put into the ink containing tube. It is filled. The material used for the chip holder is higher than the surface energy of the solvent used for the oil-based ink, and specifically, metal or ceramic such as stainless steel, nickel silver, etc. having high strength is used.

In the oil-based ballpoint pen of the present invention, the vehicle of the ink filled therein has self-lyophobic property with respect to the high energy surface (metals such as stainless steel) used for the tip holder, and the ink viscosity is 200 mPa. Since it is s or less, it does not cause fluffing with a low writing pressure, and even if a long line is continuously written, the tip wears little, and thus blurring and writing failure do not occur. In general, ink can achieve a light writing feel by lowering the viscosity, but in the case of oil-based ink, low viscosity results in an increase in wetting speed and a decrease in lubricity, resulting in an increase in flapping. Tip wear is relatively low when the viscosity is high, but increases as the viscosity decreases. 200 mPa · s
The following is the boundary lubrication region, where excessive wear occurs. However, by imparting self-lyophobicity to the ink as in the present invention, it becomes difficult for the ink to get wet on the chip holder when the ball rotates, and at the same time, the ink is self-lyophobic. Liquid molecules and oleophobic additives are adsorbed on the solid surface and the presence of the oriented molecules improves lubricity and reduces wear, so that an oily ballpoint pen with a smooth and light writing feel can be obtained. The viscosity of ink affects the speed of wetting, lubricity and writing quality. The anti-fogging effect of the above ink appears due to the decrease in viscosity. At tens of thousands to thousands of mPa · s, there is not much change, and at 1000 mPa · s or less, the anti-battering effect is obtained, but at 200 mPa · s or less, the effect is remarkably exhibited. As for writing, the viscosity does not change so much at tens of thousands to thousands of mPa · s, but it improves at 1000 mPa · s or less, 200 mPa
・ A clearer improvement is observed at s or less.

The material having a high surface free energy as used in the present invention usually has a surface energy of 50 to several thousand erg / cm ² and is easily wet by a solvent generally used for oil-based ink or the ink itself. Specific examples thereof include metals such as stainless steel, bronze, and nickel silver, metal oxides, metal salts, and nonmetals such as glass and ceramics.

The ink of the present invention may contain other resins and fixing agents other than the resins used as the aggregating agent, dispersant, etc., if necessary. Further, a rust preventive agent, a lubricant, an antiseptic agent and the like can also be used. These materials should not detract from the vehicle's self-lyophobic properties. When an ink is made by mixing a flocculant, a pigment, etc. in this vehicle, the cohesive force of the flocculant may seem to cause a loss of the self-lyophobic property. Sex evaluation is difficult. When a shearing stress is applied to the ink by the rotation of the ball, the cohesive force is weakened and the inherent self-lyophobic property of the vehicle is developed.

These inks according to the present invention preferably have a self-lyophobic property with respect to the surface of the material whose vehicle has a high surface free energy. It is preferable that the solvent itself has a self-lyophobic property, but in the case where the solvent has no self-lyophobic property, an oleophobic additive may be added, and basically the vehicle itself has a high surface free energy. It is ideal to have self-lyophobic property to the surface of the material having

[0023]

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

Self-lyophobic property: The contact angle was measured by observing the state in which ink or vehicle was dropped on a stainless plate with a microscope. Viscosity: E type viscometer (Tokyo Keiki EMD type, EHD type)
At 25 ° C./50 rpm. Since only Comparative Example 5 has a high viscosity, the EHD type was used. Bote: The amount of ink adhering to the tip of a chip after 100 m writing was visually compared and evaluated (average of 10 lines) with a mechanical writing tester. ◎ ... No adhesion, ○ ... Small adhesion, △ ... Slight adhesion, ×
... very much adhesion

Writing quality: The writing feeling was compared and evaluated by freehand writing.・ Writability: The freehand writing was used to continuously write the spiral and observe the line drawing state. -DC test: The pen tip was left facing downward in a constant temperature room at 25 ° C and 65% for 3 days, and the amount of ink attached to the pen tip was visually evaluated for comparison. Small adhered amount: ○>△> ×: Large adhered amount ・ Cap-off performance; 50 ° C to 65 as a forced deterioration test
Comparative evaluation of the writing state after left for 1 month without a cap under the environment of ℃. ○: Good, △: Slightly blurred, ×: Not writable ・ Non-Newtonian viscosity index (n); Viscosity with respect to viscometer rotation speed (R) using E type viscometer (Tokyo Keiki EMD type, EHD type) By obtaining the value of (η) and plotting the viscosity (η) on the vertical axis and the value of viscometer rotation speed (R) on the horizontal axis of this logarithmic graph, the index (n) can be calculated from the gradient (n-1). ) Was asked.

The components of the compositions shown in Table 1 used in Examples and Comparative Examples are as follows. Colorant: (1) is a dye "Varifast Black # 3830" [manufactured by Orient Chemical Industry Co., Ltd.], (2) is a carbon black "Printex # 35" [manufactured by Degussa Co., Ltd.],
(3) is "azo pigment # 1010" [Fuji Dye Co., Ltd.]
Made], (4) is "Varifast Violet # 170
1 "[manufactured by Orient Chemical Industry Co., Ltd.], (5) is" Varifast Yellow # 1105 "[manufactured by Orient Chemical Industry Co., Ltd.] (6) is" Spiron Black GMHsp "[manufactured by Hodogaya Chemical Co., Ltd.] Pigment dispersant: polyvinyl butyral was used (1) "S-REC B BM-1" [manufactured by Sekisui Chemical Co., Ltd.], (2) "S-REC B BL-1" [〃] Resin: (1) is "PVP K-30" [made by GAF Co., Ltd.] (2) is "PVP K-90" [〃]

Solvent: Solvent (1): Ethylene glycol monophenyl ether, (0.03 mmHg / 20 ° C) Solvent (2): Polypropylene glycol (molecular weight 40
0), (0.02 mmHg / 20 ° C or less) Solvent (3): Tripropylene glycol monobutyl ether, (0.02 mmHg / 20 ° C or less) Solvent (4): Diethylene glycol monomethyl ether, (0.18 mmHg / 25 ° C) Solvent (5): Benzyl alcohol, (1 mmHg / 58 ° C) Solvent (6): Triethylene glycol monobutyl ether, (0.01 mmHg / 20 ° C) Solvent (7): Ethylene glycol monomethyl ether,
(9.7 mmHg / 25 ° C.) Solvent (8): Triethylene glycol monoethyl ether, (0.01 mmHg / 20 ° C. or less) Oleophobic additive: (1) Perfluoroalkyl phosphate ester “F-19”
1 "[manufactured by Dainippon Ink and Chemicals, Inc.], (2) alkyl phosphate ester" RL-210 "[Toho Chemical Co., Ltd.]
Co., Ltd.], (3) Oleic acid coagulant: (1) "Tarene BA-600" (manufactured by Kyoeisha Chemical Co., Ltd.), (2) Lipophilic smectite "SEN" (manufactured by Corp Chemical Co., Ltd.), (3). Lipophilic smectite "SPN" [manufactured by 〃 Co., Ltd.]

Examples 1 to 5 and Comparative Examples 1 to 7 Ballpoint pen inks were prepared according to the formulations shown in Table 1 (parts by weight). The test results are shown in Table 1 with a ballpoint pen filled with this ink. Comparative Example 1 has a large vehicle n value, Comparative Example 2 has a small n value, Comparative Example 3 has a high solvent vapor pressure, and Comparative Example 4 has a vehicle contact angle of less than 5 °. Example 5,
No. 6 is an example with high viscosity and a large n value. Comparative Example 7 is an example in which the viscosity is 200 mPa · a or more even when the n value is 0.5 or less. This deteriorates the flow of ink in the capillaries of the ink flow path, causing blurring and inability to write.

[0029]

[Table 1]

Reference Example Table 2 shows an example of a medium viscosity aqueous ink.

[Table 2]

[0031]

INDUSTRIAL APPLICABILITY Since the ink for a ballpoint pen of the present invention does not cause the phenomenon of battering or direct current, a clear line can be drawn without the transfer of a lump of ink at the beginning of writing. Moreover, the cap-off performance is excellent, and the writing feel during writing is also good.

─────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] September 13, 1995

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0016

[Correction method] Change

[Correction contents]

The ink of the present invention has a non- Newtonian viscosity index n of 0.2 to 0.5 (25 ° C.). This n is defined by the following flow equation: S = μD ⁿ [where S is the shear stress and D is the shear rate]. The non-Newtonian viscosity index n is preferably 0.2.
~ 0.4. When n exceeds 0.5, a direct current phenomenon occurs, and when it is less than 0.2, the writing property of the ink is poor, and blurring or inability to write occurs.

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0017

[Correction method] Change

[Correction contents]

The viscosity of the ink of the present invention is 200 mPa.s.
(25 ° C., 50 rpm) or less is required. It is preferably 100 mPa · s (25 ° C, 50 rpm) or less, more preferably 50 mPa · s (25 ° C, 50 rpm) or less. Self-lyophobicity and contact angle do not include a time factor, and therefore represent an equilibrium state. If the vehicle is in is actually but should no longer blobbing phenomenon theoretically if Shimese self lyophobic high viscosity, the effect of self lyophobic slow down to repel droplets wanes. In other words, the battering phenomenon is determined by both the self-lyophobic property (contact angle) of the vehicle and the viscosity of the ink. The viscosity is 200 mPa · s or less, and the battering phenomenon disappears when the contact angle is large, but the viscosity is 200 mPa · s. If the contact angle becomes smaller than the above range, the phenomenon of "battering" will occur.

[Procedure 3]

[Document name to be amended] Statement

[Name of item to be corrected] 0025

[Correction method] Change

[Correction contents]

Writing quality: The writing feeling was compared and evaluated by freehand writing.・ Writability: The freehand writing was used to continuously write the spiral and observe the line drawing state. -DC test: The pen tip was left facing downward in a constant temperature room at 25 ° C and 65% for 3 days, and the amount of ink attached to the pen tip was visually evaluated for comparison. Small amount of adhesion: ○ ＞ △ ＞ ×: Large amount of adhesion ・ Cap-off performance; 50 ℃ as a forced deterioration test , humidity
Comparative evaluation of the writing state after left for 1 month without a cap in a 65% environment. ○: Good, △: Slightly blurred, ×: Not writable ・ Non-Newtonian viscosity index (n); Viscosity with respect to viscometer rotation speed (R) using E type viscometer (Tokyo Keiki EMD type, EHD type) By obtaining the value of (η) and plotting the viscosity (η) on the vertical axis and the value of viscometer rotation speed (R) on the horizontal axis of this logarithmic graph, the index (n) can be calculated from the gradient (n-1). ) Was asked.

Claims (6)

[Claims] 1. An organic solvent having a vapor pressure of 0.2 mmHg (20 ° C.) or less, a colorant, and a coagulant, the content of 0.2 to
Non-Newtonian viscosity index of 0.5, 200 mPa · s (25
Oil-based ballpoint pen ink having a viscosity of ℃, 50 rpm) or less. 2. (a) Vapor pressure is 0.2 mmHg (20 ° C.)
A self-phobic material which contains the following organic solvent, pigment dispersant and, if necessary, an oleophobic additive and has a contact angle of 5 to 40 ° with respect to the surface of a material having high surface free energy such as stainless steel and bronze. Liquid vehicle; (b)
An oil-based ballpoint pen ink having a non-Newtonian viscosity index of 0.2 to 0.5 and a viscosity of 200 mPa · s (25 ° C., 50 rpm) or less, which contains a flocculant; and (c) a pigment. 3. A vapor pressure of 0.2 mmHg (20)
Self-phobicity, which comprises an organic solvent having a temperature of ℃) or less, a dye and optionally an oleophobic additive, and has a contact angle of 5 to 40 ° with respect to the surface of a material having a high surface free energy such as stainless steel or bronze. An oil-based ballpoint pen ink having a liquid vehicle; and (b) a non-Newtonian viscosity index of 0.2 to 0.5 and a viscosity of 200 mPa · s (25 ° C., 50 rpm) or less, which contains a flocculant. 4. A direct-drain type oil-based ballpoint pen equipped with a pen tip composed of a ball and a tip holder and an ink container, containing an organic solvent having a vapor pressure of 0.2 mmHg (20 ° C.) or less, a colorant and a coagulant. An oil-based ballpoint pen comprising an ink container filled with an ink having a non-Newtonian viscosity index of 0.2 to 0.5 and a viscosity of 200 mPa · s (25 ° C., 50 rpm) or less. 5. A direct-drain type oil-based ballpoint pen having a pen tip composed of a ball and a tip holder and an ink containing tube, wherein (a) an organic solvent having a vapor pressure of 0.2 mmHg (20 ° C.) or less, a pigment dispersant, and A self-lyophobic vehicle containing a oleophobic additive as required and having a contact angle of 5 to 40 ° with respect to the surface of a material having a high surface free energy such as stainless steel and bronze; (b) a flocculant And (c) a non-Newtonian viscosity index of 0.2 to 0.5 containing a pigment, and an ink containing tube filled with an ink having a viscosity of 200 mPa · s (25 ° C., 50 rpm) or less. Oil-based ballpoint pen. 6. A direct-drain type oil-based ballpoint pen having a pen tip composed of a ball and a tip holder and an ink containing tube, wherein (a ′) an organic solvent having a vapor pressure of 0.2 mmHg (20 ° C.) or less, a dye, and a necessary component. The material has an oleophobic additive, and has a contact angle of 5 with respect to the surface of a material such as stainless steel or bronze having a high surface free energy.
A self-lyophobic vehicle of -40 °; and (b) a non-Newtonian viscosity index of 0.2-0.5 with a flocculant, 20.
An oil-based ballpoint pen comprising an ink containing tube filled with an ink having a viscosity of 0 mPa · s (25 ° C, 50 rpm) or less.