JP5926503B2 - Water-based ballpoint pen ink composition and retractable water-based ballpoint pen using the same - Google Patents

Description

  The present invention relates to an ink composition for water-based ballpoint pens, and more particularly, to an ink composition for water-based ballpoint pens having excellent scratching performance, crying performance and hand oil performance, and a water-based ballpoint pen using the same.

  Conventionally, it is well known that water-based ballpoint pens have reduced ink viscosity compared to oil-based ballpoint pens, excellent writing feel, fresh handwriting, and superior characteristics not found in oil-based ballpoint pens. Yes. While these water-based ballpoint pens have excellent characteristics, handwriting scratching performance is inferior, and handwriting tends to cry.

  In order to improve the scuffing performance and crying performance, a new additive in the water-based ballpoint pen ink composition is disclosed in Japanese Patent No. 3773322, “Pseudoplastic water-based ballpoint pen ink”, Japanese Patent Application Laid-Open No. 2002-2002. JP-A-2001-121868, “Ballpoint pen ink”, and the like have been disclosed as a “ballpoint pen” in Japanese Patent No. 36775 and a new ballpoint pen in which a thin film is coated on a ball base material.

"JP 2002-36775 A" "Japanese Patent Laid-Open No. 2001-121868"

  Moreover, in patent document 1, although what consists of lead naphthenate, cobalt naphthenate, and manganese naphthenate was used as a handwriting desiccant, the performance which fully satisfy | fills about scuffing performance and crying bottling performance was not obtained.

  In addition, as in Patent Document 2, a ballpoint pen in which a thin film made of a coating material having high water retention was coated on a ball base material was used. However, since wettability is too high, ink that is not consumed as handwriting remains attached to the ball. I had a problem with the performance of crying.

  In addition, when using notebooks, etc., hand grease adheres to the paper surface by repeating hand turning, resulting in line skipping and blurring at the time of writing. In Patent Documents 1 and 2, satisfactory performance was not obtained with respect to hand grease performance. Therefore, it was thought that the problems of scratching performance, tearing performance, and grease performance could be solved by paying attention to the recovery behavior of a specific ink viscosity.

  The objective of this invention is providing the ink composition for water-based ball-point pens which are excellent in a scraping performance, a tearing performance, and a greasy performance in a water-based ink composition.

In order to solve the above problems, the present invention
“1. In an aqueous ballpoint pen ink composition comprising at least water, a colorant, xanthan gum, and a surfactant, the surfactant is a fluorosurfactant having a perfluoroalkylethyleneoside adduct, and the colorant is Carbon black having an oil absorption of 50 to 80 (g / 100 g) , and the surface tension of the water-based ballpoint pen ink composition is 10 to 25 mN / m in an environment of 20 ° C. Then, when the ink composition for water-based ballpoint pens, to which rotational shear at a shear rate of 500 (sec ⁻¹ ) was applied, was measured at the start point of measurement of ink viscosity at a shear rate of 0.1 (sec ⁻¹ ) in an environment of 20 ° C. In the case of 0 (sec), the ink viscosity at a shear rate of 0.1 (sec ⁻¹ ) after the lapse of A (sec) time is V _A (Pa · s), and the shear rate after the lapse of B (sec) of 0. ink viscosity of 1 (sec ^-1) When V _B (Pa · s), the relationship of the elapsed time and the ink viscosity is a _{0.01 ≦ (V B -V A /BA)≦0.7} , the ink viscosity V _A (Pa · s) V _B (Pa · s) is 6 to 12 (Pa · s), an ink composition for water-based ballpoint pens (A and B are integers, A <B, 0 <A, B ≦ 10) A ballpoint pen having a ballpoint pen tip which is rotatably held in the ball holding chamber of the chip body directly or via a tip holder. The refill is a water-based ballpoint pen that is slidably arranged in the shaft tube. Under the conditions of a writing angle of 65 °, a writing load of 100 g, and a writing speed of 4 m / min, the ink consumption per 100 m of the water-based ballpoint pen is 80- Aqueous water characterized by being 250 mg / 100 m Rupen.
2. The content of the fluorosurfactant having the perfluoroalkylethylene oside adduct is 0.01 to 1.0% by mass with respect to the total amount of the ink composition. Water-based ballpoint pen.
3. A water-based ballpoint pen, wherein the ballpoint pen refill according to item 1 or 2 is slidably disposed in a shaft tube so that the ballpoint pen tip can be projected and retracted from a tip opening of the shaft tube. "

  The present invention uses a water-based ballpoint pen ink composition exhibiting a specific ink viscosity behavior to improve the ink penetrability on the paper surface, thereby improving the scratching performance and improving the ink return on the ball surface. The effect of obtaining an aqueous ball-point pen ink composition and water-based ballpoint pen excellent in hand performance and excellent in the performance of hand grease that can be well written on the paper surface to which the oil is attached.

The relationship between time (sec) and shear rate (sec ^-1 ) when the ink composition for water-based ballpoint pens of the present invention is measured is shown. The relationship of time (sec)-ink viscosity (Pa * s) when measuring the ink composition for water-based ball-point pens of this invention is shown.

The water-based ballpoint pen ink composition comprising at least water, a colorant, and a pseudoplasticity imparting agent is characterized in that the water-based ink is subjected to rotational shear at a shear rate of 500 (sec ⁻¹ ) in an environment of 20 ° C. When an ink composition for a ballpoint pen is measured at 0 (sec) at an ink viscosity of 0.1 (sec ^-1 ) in an environment of 20 ° C, the shear rate after the elapse of A (sec) time. The ink viscosity at 0.1 (sec ⁻¹ ) is V _A (Pa · s), and the ink viscosity at a shear rate of 0.1 (sec ⁻¹ ) after elapse of B (sec) is V _B (Pa · s). Then, the relationship between the elapsed time and the ink viscosity is 0.01 ≦ (V _B −V _A /(BA)≦1.0, and the ink viscosities V _A (Pa · s) and V _B (Pa · s). ) Is from 6 to 30 (Pa · s) (A and B are integers, A <B, 0 <A, B ≦ 1) A)

The present invention provides an aqueous ballpoint pen ink composition obtained by applying rotational shearing at a shear rate of 500 (sec ⁻¹ ) to the aqueous ballpoint pen ink composition in a 20 ° C. environment at a shear rate of 0.1 (sec ^{− 1} ) The ink viscosity behavior when the ink viscosity measurement start time is set to 0 (sec) makes it possible to improve handwriting scratching performance after writing and crying performance. I understood that

In order to improve the brush scuffing performance during writing and the performance of crying, to investigate the behavior of a series of ink viscosities from writing to handwriting drying after writing, the rotation of the ball during writing The ink viscosity at a shear rate of 500 (sec ^-1 ) is assumed to be sheared, and the ink viscosity at a shear rate of 0.0 (sec ^-1 ) at rest is an approximate value for ink on paper after writing. The ink viscosity at a shear rate of 0.1 (sec ⁻¹ ) was studied with attention.

Therefore, as a result of earnest research, the inventor of the present application has found that there is a correlation between the behavior of the ink viscosity at the shear rate and the scratching performance and the tearing performance, and the time A (sec) and time B (sec) By setting the ink viscosity V _A (Pa · s) and V _B (Pa · s) to 0.01 ≦ (V _B −V _A /BA)≦1.0, the ink viscosity is gradually recovered. Because the ink fluidity becomes better, the ink permeability to the paper surface is improved, the rubbing performance is improved, the ink return of the ball surface is improved, the tearing performance is improved, and a fresh handwriting can be obtained. I understand. Furthermore, since it penetrates well to the paper surface to which the hand grease is attached, the hand grease performance can be improved. On the other hand, when (V _B -V _A /BA)>1.0, the ink viscosity is recovered too early, the ink permeability is poor, the ink return on the ball surface is poor, and the desired scuffing performance and tearing performance are achieved. I can't get it. Here, as an evaluation method of the present invention, JIS P3105 stipulates the suitability of scratching for 20 seconds after writing in the handwriting rubbing test, but in the present invention, the improvement of handwriting rubbing performance is further improved. Since it is aimed, the suitability of the scratching property 10 seconds after writing shall be measured and evaluated (A and B are integers, A <B, 0 <A, B ≦ 10).

Considering the tendency to further improve the ink fluidity and improve the scratching performance and crying performance, 0.01 ≦ (V _B −V _A /BA)≦0.7 is preferable, and most preferably 01 ≦ (V _B −V _A /BA)≦0.5 is preferable.

The ink viscosities V _A (Pa · s) and V _B (Pa · s) are 6 to 30 (Pa · s) at a shear rate of 0.1 (sec ⁻¹ ) in an environment of 20 ° C. ). If the ink viscosity is less than 6 (Pa · s), the ink viscosity is too low and the ink sag is inferior. If it exceeds 30 (Pa · s), the rubbing performance, the tearing performance, and the ink followability are inferior. It is because it ends up. Considering the tendency to further improve the rubbing performance, tearing performance, and ink followability, 6 to 12 (Pa · s) is preferable.

Further, the ink composition for water-based ballpoint pens exhibiting a behavior in which the ink viscosity is gradually recovered, such as 0.01 ≦ (V _B −V _A /BA)≦1.0. To improve oil performance, select and contain one or more surfactants selected from silicone surfactants, acetylene glycol surfactants, fluorosurfactants, and dialkylsulfosuccinates. Is preferred. This is because the surface tension tends to be reduced, and the penetrating performance and the grease performance tend to be improved by increasing the permeability to the paper surface. Among the surfactants, a fluorosurfactant is preferably used in order to further improve the scratching performance and hand fat performance. This is because the fluorosurfactant can reduce the surface tension the most, has the effect of improving the wettability, facilitates spreading of the ink, and has a hydrophobic surface attached hand grease. This is because good handwriting can be easily obtained. Therefore, the recovery behavior of the ink viscosity is shown, and by using the surfactant in combination, the effect of improving the scuffing performance and hand grease performance can be obtained.

  Examples of the silicone surfactant include polyether modified, methyl styryl modified, alkyl modified, higher fatty acid ester modified, hydrophilic special modified, fluorine modified, silicone oil such as dimethyl, methylphenyl and the like. Fluorosurfactants include perfluoro group butyl sulfonate, perfluoro group-containing carboxylate, perfluoro group-containing phosphate ester, perfluoro group-containing phosphate ester type compound, perfluoroalkyl ethylene oxide adduct, Fluoro group / hydrophilic group / lipophilic group-containing oligomer, perfluoro group / hydrophilic group-containing oligomer, perfluoro group / lipophilic group-containing oligomer, perfluoroalkyl betaine, perfluoroalkylamine oxide compound and the like. Among these, it is preferable to use a perfluoroalkylethylene oxide adduct. This is because if ethylene oxide is present, the hydrophilicity is strong, so that it is easily dissolved in water and the stability over time tends to be stable. Furthermore, a fluorosurfactant of a perfluoroalkylethylene oxide adduct can be preferably used because it can suppress handwriting and blurring even on a writing surface to which hand grease is attached.

  As for the surfactant, specific examples of the silicone surfactant include KF-351, KF-352, KF-353, KF-354, KF-355, KF-615, KF-618, KF-642. , KF-643, KF-945, KF-6004 (Shin-Etsu Chemical Co., Ltd.), FZ-2104, FZ-2110, FZ2163, FZ-2191, FZ-7002, FZ-720, SILWETL-7001, L-7002 Y-7006, L-7604 (Toray Dow Corning Co., Ltd.), TSF4445 (Toshiba Silicone Co., Ltd.). Specific examples of the acetylene glycol surfactants include DYNOL 604, Surfynol 104H, 104A, 104BC, 104DPM, 104PA, 104S, 420S, 420, 440, SE, SE-F, 61. Etc. (Air Products Japan Co., Ltd.). Specific examples of the fluorosurfactant include Megafac F-447, F-410, F-444, F-445, F-552, F-553, F-554 (DIC Corporation), DSN-403N. (Daikin Industries Co., Ltd.), FC-170C, FC-430, Novec FC-4430, FC-4432 (Sumitomo 3M Co., Ltd.) and the like. Specific examples of dialkyl sulfosuccinates include Neocor SW-C, Neocor YSW-CE, Neocor YSK (Daiichi Kogyo Seiyaku Co., Ltd.), Perex OT-P, Perex TR, Perex CS, Perex TA (Kao Corporation) , Aerol OB-70 (Toho Chemical Industry Co., Ltd.), Aerosol MA-80, Aerosol AY-100 (Mitsui Cyanamid Co., Ltd.), Adeka Coal EC (Adeka Co., Ltd.), and the like. You may use these individually or in mixture of 2 or more types.

  The content of the surfactant is preferably 0.01 to 5.0% by mass with respect to the total amount of the ink composition. If it is lower than this range, it is difficult to sufficiently reduce the surface tension, and if it exceeds this range, the handwriting tends to bleed or the ink aging tends to become unstable, so 0.01 to 5.0% by mass. preferable. Considering the tendency to improve handwriting bleeding, it is preferably 0.1 to 3.0% by mass, and most preferably 0.1 to 1.0% by mass.

  Further, the surface tension of the water-based ink composition of the present invention is more preferably 10 to 35 mN / m in an environment of 20 ° C. If it falls below this range, there is a tendency for the handwriting to bleed out and the paper to slip through easily, and if it exceeds this range, there is a tendency to easily affect the grease performance. It is preferable to be -35 mN / m. Considering the tendency to improve the grease performance, 10 to 25 mN / m is preferable.

  Further, the colorant is not particularly limited, such as a dye or a pigment, and can be appropriately selected and used. As the dye, direct dyes, acid dyes, basic dyes, metal-containing dyes, various salt-forming dyes, and the like can be used. Examples of pigments include inorganic, organic, and processed pigments. Specific examples include carbon black, aniline black, ultramarine, yellow lead, titanium oxide, iron oxide, phthalocyanine, azo, quinacridone, quinophthalone, and selenium. , Triphenylmethane, perinone, perylene, glyoxazine, aluminum pigment, pearl pigment, fluorescent pigment, phosphorescent pigment, and complementary color pigment. These dyes and pigments may be used alone or in combination of two or more. The content is preferably 1 to 20% by mass relative to the total amount of the ink composition.

Among these, for the colorant, it is preferable to use carbon black having an oil absorption of 1 to 100 g in order to improve the grease performance. The oil absorption amount of carbon black is a characteristic indicating the structure of carbon black, and is an amount by which a certain amount of dried carbon black absorbs DBP (dibutyl phthalate) and is measured by a test method defined in JISK6221. Oil absorption is an alternative characteristic that represents the structure that is the connection of carbon black. The larger the oil absorption, the larger the structure. In particular, the oil absorption is 100
When carbon black exceeding g is included, the structure is too large, and the permeability to paper tends to be poor. It tends to be difficult to obtain. Therefore, when carbon black having an oil absorption of 1 to 100 g with a moderately adjusted structure is contained, it tends to penetrate well into the paper surface to which hand grease has adhered, and further to suppress blurring of handwriting and line skipping. is there. Furthermore, the oil absorption is preferably 50 to 100 g (/ 100 g) in consideration of dispersion stability, and 50 to 80 g (/ 100 g) is most preferable in consideration of the grease performance. Therefore, the recovery behavior of the ink viscosity is exhibited, and the use of carbon black having an oil absorption of 1 to 100 g tends to provide an effect of further improving the grease performance.

  Examples of the pseudoplasticity imparting agent include polysaccharides such as xanthan gum, welan gum, succinoglycan, guar gum, locust bean gum, λ-carrageenan, cellulose derivatives, diyutan gum, and polyacrylic acid.

Among them, it is preferable to use at least xanthan gum. This is because the viscosity of the ink is likely to recover gradually such that the behavior of the ink viscosity is 0.01 ≦ (V _B −V _A /BA)≦1.0. This is because there is a tendency. Further, if the handwriting has a blur, it becomes a factor that the handwriting scratching property is delayed. Therefore, xanthan gum has a tendency that the stickiness is not easily generated, and can be used for improving the scratching property.

  The content of the pseudoplasticity imparting agent is preferably 0.1% by mass to 1.0% by mass with respect to the total amount of the ink composition. This is because if it is lower than this range, it is difficult to obtain a desired ink viscosity, and if it exceeds this range, the ink following performance tends to be inferior.

  Further, the surface tension of the water-based ink composition of the present invention is more preferably 10 to 35 mN / m in an environment of 20 ° C. If it falls below this range, there is a tendency for the handwriting to bleed out and the paper to slip through easily, and if it exceeds this range, there is a tendency to easily affect the grease performance. It is preferable to be -35 mN / m. Considering the tendency to improve the grease performance, 10 to 25 mN / m is preferable.

  In addition, in order to improve the stability and lubricity of water-soluble organic solvents such as glycols such as ethylene glycol and glycerin, and colorants, in order to prevent moisture dissolution stability and moisture evaporation and drying As phosphates and lubricants, phosphate surfactants, fatty acids, etc., antibacterial agents such as 1,2 benzoisothiazolin-3-one, moisturizers such as urea and sorbit, rust inhibitors such as benzotriazole, ethylenediamine A chelating agent such as acetic acid can be added. Also, a dispersant can be added as appropriate, and water-soluble resins such as acrylic resins, alkyd resins, polyvinylpyrrolidone, polyvinyl alcohol, etc., and resin emulsions such as acrylic resins, urethane resins, styrene-butadiene resins, and polyester resins Resin, vinyl acetate resin and the like can be added. These can be used alone or in combination of two or more.

Next, an Example is shown and this invention is demonstrated.
Example 1
Water 67.0 parts by weight pigment (oil absorption: 69 g (/ 100 g)) 6.0 parts by weight water-soluble solvent (glycerin) 10.0 parts by weight water-soluble solvent (ethylene glycol) 10.0 parts by weight dispersant (styrene-acrylic Resin) 3.0 parts by mass Fluorine-based surfactant (perfluoroalkylethylene oxide adduct) 1.0 part by mass
Lubricant (phosphate ester surfactant) 1.0 part by mass pH adjuster (triethanolamine) 3.0 part by mass rust inhibitor (benzotriazole) 0.5 part by mass antibacterial agent (1,2 benzoisothiazoline -3-one) 0.5 mass part pseudoplasticity imparting agent (xanthan gum) 0.40 mass part

  First, collect appropriate amounts of pigment, dispersant, water-soluble solvent, water and pH adjuster, disperse thoroughly using a disperser such as a bead mill, ball mill, roll mill, etc., and centrifuge to remove coarse particles. Thus, a pigment dispersion is obtained. Thereafter, the prepared pigment dispersion, water-soluble solvent, water, lubricant, pH adjuster, rust inhibitor, and antibacterial agent are heated and stirred with a magnetic hot stirrer to create a base ink.

  Then, while heating the base ink prepared above, the thickener was added and sufficiently mixed and stirred using a homogenizer stirrer until uniform, and then filtered using filter paper. An ink composition for aqueous ballpoint pens was obtained. Further, the surface tension was measured by a vertical plate method using a surface tension measuring instrument manufactured by Kyowa Interface Science Co., Ltd. and a glass plate in an environment of 20 ° C. and found to be about 18 mN / m.

Examples 2-6
As shown in Table 1, water-based ink compositions of Examples 2 to 8 were obtained in the same procedure as in Example 1 except that each component was changed to a blend.

Comparative Examples 1-3
As shown in Table 2, water-based ink compositions of Comparative Examples 2 to 6 were obtained in the same procedure as in Example 1 except that each component was changed to blending.

(Relationship between ink viscosity (Pa · s) and time (sec) (V _B -V _A / BA) measurement method)
The ink viscosity of the water-based ballpoint pen ink composition prepared in Example 1 is 20 using a rheometer AR-G2 viscometer (cone plate 40 mm, angle 2 °, measurement temperature 20 ° C.) manufactured by TA Instruments. Under an environment of 0 ° C., rotational shear at a shear rate of 500 (sec ⁻¹ ) was applied for 60 seconds, and then the shear shear was lowered to 0.1 (sec ⁻¹ ) and measured every 10 seconds for 10 seconds. However, in 5 seconds and 10 seconds (A = 5, B = 10), V _A = 6.5, V _B = 9.55, and (V _B −V _A /B−A)=0.61. there were. In Examples 2 to 6 and Comparative Examples 1 to 3, the measured values were calculated by the same measurement method. Tables 1 and 2 show the results and evaluation of the calculated values of (V _B −V _A / BA) at 5 seconds and 10 seconds (A = 5, B = 10). Moreover, the ink viscosity of Examples 1-6 was the range of 6-30 (Pa * s).

Test and Evaluation A ballpoint pen tip in which the water-based ink composition produced in Examples 1 to 6 and Comparative Examples 1 to 3 was held in a tip holder of an ink containing cylinder rotatably with a ball having a ball diameter of 0.5 mm was used as a chip holder. A knock-type ballpoint pen filled in an ink containing cylinder (made of polypropylene) was prepared, and the following tests and evaluations were performed. In addition, the evaluation of the rubbing performance test, the tearing performance test, and the hand grease performance test was evaluated by the following test method using JIS P3201 writing paper A as the writing test paper. Artificial sebum used for hand fat performance test is 3.0 parts by weight squalane, 6.0 parts by weight isopropyl myristate, 12.0 parts by weight olive oil, 0.6 parts by weight cholesterol, 0.6 parts by weight palmitic acid, An artificial sebum was prepared by stirring and mixing 3.9 parts by weight of oleic acid, 3.9 parts by weight of isostearic acid, and 70.0 parts by weight of acetone.

Scratch performance test: After writing on the paper, it was rubbed with a finger and the handwriting dryness was observed.
Written hand dried in less than 5 seconds
Written in 5 to 10 seconds after writing
The handwriting did not dry after 10 seconds of writing

Crying performance test: After writing on paper, the handwriting was observed.
Things without crying bots ... ◎
Even if there is a crying bot, it is at a level where there is no practical problem ... ○
Things that have a lot of crying and poor practicality ・ ・ ・ ×

Hand oil performance test: The handwriting written on the paper surface to which artificial sebum was attached was observed.
Lines in the handwriting with no blurring ... ◎
The handwriting has a slight line skip and a blurring.
There are lines in the handwriting and blurring, but there are no practical problems.
There are lines in the handwriting, blurring, but it is terrible and poor in practicality ... ×

  From the result of Table 1, in Examples 1-6, the level of the performance which is satisfactory or practically has no problem in the rubbing performance test, the tearing performance test, and the hand grease performance test.

In Comparative Example 1, the relationship (V _B −V _A / BA) between the ink viscosity (Pa · s) and time (sec) is 5 seconds, 10 seconds (A = 5, B = 10), and V _A = Since 14.0, V _B = 21.3, and (V _B −V _A /BA)=1.46 (V _B −V _A /BA)>1.0, the handwriting dryability I was bad and my crying was terrible. Similarly, in Comparative Examples 2 and 3, since (V _B −V _A /BA)>1.0, handwriting dryness was poor and crying was severe.

Further, in Comparative Example 3, (V _B −V _A /BA)>1.0, and selected from silicone surfactants, acetylene glycol surfactants, fluorosurfactants, and dialkylsulfosuccinates. Since there was no one or more surfactants, the handwriting performance test showed sharp lines and blurring.

In particular, a ballpoint pen refill comprising a ballpoint pen tip holding a ball rotatably in a ball holding chamber of a chip body directly or via a tip holder at the tip of an ink containing cylinder directly packed with an ink composition for water-based ballpoint pens. In a knock-type water-based ballpoint pen or a rotary feed-out type water-based ballpoint pen, etc., wherein the ballpoint pen tip is slidably disposed in the shaft tube so that the ballpoint pen tip can be projected and retracted from the tip opening of the shaft tube. Since drooping becomes a problem, an ink composition for water-based ballpoint pens having an ink viscosity of 6 to 30 (Pa · s) at a shear rate of 0.1 (sec ⁻¹ ) in an environment of 20 ° C. as in the present invention. It can be suitably used.

  In the present embodiment, the coil spring that presses the ball is not provided on the inner wall of the tip end edge of the ballpoint pen tip, but the effect of suppressing ink sag is improved by providing the coil spring, which is more preferable.

As for ink consumption, the water-based ball-point pen ink composition of the present invention is used as a water-based ball-point pen directly packed in an ink containing cylinder, and the writing paper is written on JIS P3201 writing paper A with a writing angle of 65 ° and a writing load. When a spiral writing test is performed using 5 test samples at a writing speed of 4 m / min under the condition of 100 g, and the average value of the ink consumption per 100 m is defined as the ink consumption per 100 m. The ink consumption per 100 m is preferably 50 to 300 mg / 100 m. If it is less than this range, the ink consumption is small, so the handwriting is likely to be blurred. If it exceeds this range, the ink consumption is large, and there is a possibility of affecting the handwriting scratching. More preferably, it is 80-250 mg / 100m.

  The present invention can be used as a water-based ballpoint pen. More specifically, the present invention can be widely used as a water-based ballpoint pen filled with the ink composition for water-based ballpoint pens.

Claims (3)

In an aqueous ballpoint pen ink composition comprising at least water, a colorant, xanthan gum, and a surfactant, the surfactant is a fluorosurfactant having a perfluoroalkylethyleneoside adduct, and the colorant has an oil absorption of 50. a carbon black ~80 (g / 100g), and the surface tension of the water-based ballpoint pen ink composition, under 20 ° C. of environment are 10~25mN / m, under 20 ° C. environment, shear The water-based ballpoint pen ink composition to which rotational shearing at a speed of 500 (sec ⁻¹ ) was applied was measured at 0 (sec) at an ink viscosity measurement starting point at a shear rate of 0.1 (sec ⁻¹ ) in an environment of 20 ° C. ), The ink viscosity at a shear rate of 0.1 (sec ⁻¹ ) after the lapse of A (sec) time is V _A (Pa · s), the shear rate of 0.1 (sec after the lapse of B (sec) time. ^-1 ) V _B ( Pa · s), the relationship between the elapsed time and the ink viscosity is 0.01 ≦ (V _B −V _A /BA)≦0.7, and the ink viscosity V _A (Pa · s), V _B (Pa · s) is 6 to 12 (Pa · s), a water-based ink composition for ballpoint pens (A and B are integers, A <B, 0 <A, B ≦ 10) A ballpoint pen refill comprising a ballpoint pen tip that holds a ball rotatably in a ball holding chamber of a chip body directly or via a tip holder is directly packed in an ink containing tube. The water-based ballpoint pen is slidably disposed in the shaft cylinder, and the ink consumption per 100 m of the water-based ballpoint pen is 80 to 250 mg / 100 m under the conditions of a writing angle of 65 °, a writing load of 100 g, and a writing speed of 4 m / min. A water-based ball characterized by Down. The content of the fluorosurfactant having the perfluoroalkylethyleneoside adduct is 0.01 to 1.0% by mass with respect to the total amount of the ink composition. Water-based ballpoint pen. 3. A water-based ballpoint pen, wherein the ballpoint pen refill according to claim 1 or 2 is slidably disposed in a shaft tube, and the ballpoint pen tip can be projected and retracted from a tip opening of the shaft tube.

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