JP2008183879A - Water-based ballpoint pen - Google Patents

Abstract

An object of the present invention is to provide an aqueous ballpoint pen that has good writing quality and is excellent in stability over time by suppressing deposits such as metal salts in the ballpoint pen tip.
A water-based ballpoint pen comprising a ballpoint pen tip having a ball rotatably held in a ball holding chamber of a tip body made of stainless steel at the tip of an ink containing cylinder, either directly or via a tip holder. In the ink containing cylinder, at least water, a colorant, and a styrenated phenol-based HLB excluding phosphoester surfactants are different, and the phosphoester surfactant is phosphoric acid having an HLB of 13 or less. A water-based ballpoint pen ink composition containing at least an ester surfactant and a phosphate ester surfactant having an HLB of 14 or more is directly packed.

[Selection] Figure 1

Description

  The present invention relates to a water-based ballpoint pen, and more particularly to a water-based ballpoint pen that has good writing quality and excellent stability over time by suppressing precipitates in the ballpoint pen tip.

  Conventionally, a ballpoint pen provided with a ballpoint pen tip using a tip body made of a stainless steel material is well known. In the case of a water-based ballpoint pen using a chip body made of such a stainless steel material, precipitates such as metal salts generated by reaction of manganese ions and chromium ions such as manganese and chromium contained in the stainless steel material in the ink composition In order to prevent this, it has been proposed to add a rust inhibitor such as benzotriazole or a metal chelating agent to the ink composition.

  Such water-based ballpoint pen ink compositions and water-based ballpoint pens using the same are disclosed in Japanese Patent Publication No. 49-45333 “Water-based ink for writing” and Japanese Patent Laid-Open No. 8-41409 “Ink composition for water-based ballpoint pen”. A water-based ballpoint pen ink composition is disclosed.

JP-A-6-57194 discloses a water-based ballpoint pen ink composition in which a phosphate ester surfactant is added as a lubricant to improve writing quality. JP-A-10-316922 discloses a water-based ballpoint pen in which a metal chelating agent and a phosphate ester surfactant are added to “water-based ink composition for ballpoint pen and ballpoint pen incorporating the same”.
"Japanese Patent Publication No.49-45333" "JP-A-8-41409" "JP-A-6-57194" "Japanese Patent Laid-Open No. 10-316922"

  However, Patent Documents 1 and 2 propose water-based ballpoint pen inks to which a rust preventive agent such as benzotriazole or benzothiadiazole compound is added, but the problem is that the lubricity is poor, the writing quality is poor, and the blurring occurs. Was holding.

  Further, as in Patent Document 3, when a phosphate ester surfactant is added as a lubricant in order to improve writing quality, the phosphate ester surfactant and metal ions such as manganese ions and chromium ions in the chip Reacts to generate a metal salt. Furthermore, the phosphate ester surfactant having an HLB of 13 or less improves the writing quality, but a metal salt precipitate is generated by the reaction between the phosphate ester surfactant and the metal ions in the chip. As a result, poor writing has occurred.

  Further, as in Patent Document 4, by adding a metal chelating agent such as ethylenediaminetetraacetic acid, the metal ions eluted from the chip body are encapsulated, so that the phosphate ester surfactant and the metal ions are contained in the ink composition. By preventing the contact of the metal salt, generation of the metal salt can be suppressed. However, in order to suppress the metal salt, new problems such as the blending ratio of the phosphate ester surfactant and ethylenediaminetetraacetic acid are generated.

  By the way, the cemented carbide ball mainly composed of tungsten carbide uses cobalt, nickel or the like as its binder. Therefore, in the case of a ballpoint pen using a cemented carbide as a ball material, when a metal chelating agent is added as in Patent Document 4, the metal chelating agent has a strong reactivity, so that cobalt, nickel, etc. of the binding material are changed over time. Since it corrodes and produces rotation resistance, there was a possibility that the writing quality might be inferior.

  The object of the present invention is to provide a ballpoint pen tip using a tip body made of stainless steel, having a good writing quality, and being excellent in stability over time by suppressing precipitates due to metal salts in the tip body. To provide a ballpoint pen.

［式中、Ｒはアルキル又はアルキルアリル基を、nはエチレンオキサイド付加モル数を、Ｒ’はＨまたはＲＯ（ＣＨ_２ＣＨ_２Ｏ）_ｎ基を示す。］
４．前記ＨＬＢが１４以上のリン酸エステル界面活性剤が、フェニル基を有するリン酸エステル界面活性剤であることを特徴とした第１項ないし第３項の何れか１項に記載の水性ボールペン。
５．前記ＨＬＢが１４以上のリン酸エステル界面活性剤が、インキ組成物全質量に対し、０．１質量％以上、３．０質量％以下であることを特徴とした第１項ないし第４項の何れか１項に記載の水性ボールペン。
６．前記ＨＬＢが１３以下のリン酸エステル界面活性剤が、インキ組成物全質量に対し、０．１質量％以上、３．０質量％以下であることを特徴とした第１項ないし第５項の何れか１項に記載の水性ボールペン。
７．前記ボールが、超硬合金材からなることを特徴とした第１項ないし第６項の何れか１項に記載した水性ボールペン。」である。 In order to solve the above problems, the present invention
“1. A water-based ballpoint pen that has a ballpoint pen tip that rotatably holds a ball in a ball holding chamber of a tip body made of stainless steel at the tip of an ink containing cylinder, either directly or via a tip holder. In addition, at least water, a colorant, and a styrenated phenol-based HLB except for the HLB are different from each other, and the phosphate ester surfactant is a phosphate ester having an HLB of 13 or less. A water-based ballpoint pen comprising an ink composition for a water-based ballpoint pen that contains at least a surfactant and a phosphate ester surfactant having an HLB of 14 or more.
2. The phosphate ester surfactant having an HLB of 13 or less and the phosphate ester surfactant having an HLB of 14 or more are nonylphenol, lauryl alcohol, tridecyl alcohol, short chain alcohol, dinonylphenol, octylphenol. 2. The water-based ballpoint pen according to item 1, wherein the water-based ballpoint pen is selected from phosphoric esters of synthetic and synthetic alcohols.
3. Item 3. The aqueous ballpoint pen according to Item 1 or 2, wherein the phosphate ester surfactant is a phosphate ester surfactant represented by the following general formula (Formula 1).

[Wherein, R represents an alkyl or alkylallyl group, n represents the number of moles of ethylene oxide added, and R ′ represents H or a RO (CH ₂ CH ₂ O) _n group. ]
4). 4. The aqueous ballpoint pen according to any one of Items 1 to 3, wherein the phosphate ester surfactant having an HLB of 14 or more is a phosphate ester surfactant having a phenyl group.
5. The phosphoric acid surfactant having an HLB of 14 or more is 0.1% by mass or more and 3.0% by mass or less based on the total mass of the ink composition. The water-based ballpoint pen according to any one of the above.
6). Items 1 to 5, wherein the phosphate ester surfactant having an HLB of 13 or less is 0.1% by mass or more and 3.0% by mass or less based on the total mass of the ink composition. The water-based ballpoint pen according to any one of the above.
7). The water-based ballpoint pen according to any one of Items 1 to 6, wherein the ball is made of a cemented carbide material. Is.

  The present invention is a water-based ballpoint pen equipped with a ballpoint pen tip using a tip body made of a stainless steel material, which has good writing quality and excellent temporal stability by suppressing deposits due to metal salts in the tip body. An aqueous ballpoint pen could be provided.

  The first feature of the present invention is a water-based ballpoint pen using a ballpoint pen tip using a tip body made of a stainless steel material, and a phosphate ester surfactant having a different HLB excluding styrenated phenols, and having an HLB of 13 or less. A phosphate ester surfactant and a phosphate ester surfactant having an HLB of 14 or more are used in combination.

  The types of phosphate ester surfactants include nonylphenol, styrenated phenol, lauryl alcohol, tridecyl alcohol, short chain alcohol, dinonylphenol, octylphenol, synthetic alcohol and the like. .

  Among the phosphate ester surfactants, styrenated phenol phosphate surfactants cause steric hindrance compared to other phosphate ester surfactants because the phenol skeleton has a sterically bulky structure. Therefore, lubricity is inferior and it is difficult to improve the writing quality. Therefore, in order to further improve the writing quality, in the present invention, nonylphenol type other than styrenated phenol type, lauryl alcohol type, tridecyl alcohol type, short chain alcohol type, dinonyl phenol type, octyl phenol type, synthetic alcohol type phosphorus, etc. An acid ester surfactant is used.

  By the way, when only the phosphate ester surfactant of HLB14 or more is used, since it forms a highly hydrophilic metal salt, it dissolves in water-based ink, so no precipitate is generated, but the writing quality is improved. It is important for HLB13 excluding styrenated phenols to use the following phosphate ester surfactants. This is because the lower the HLB value, the higher the lipophilicity and the better the lubricity of the ball, thereby improving the writing quality.

  However, on the other hand, phosphoric acid ester surfactants other than styrenated phenols having an HLB of 13 or less improve the writing quality, but since the HLB value is low, the lipophilicity becomes strong and the solubility is poor. The phosphate ester surfactant reacts with metal ions such as manganese ions and chromium ions eluted from the inside of the chip body to generate a highly lipophilic metal salt. Since this highly lipophilic metal salt does not dissolve in the ink composition, it has a problem of being generated as a metal salt precipitate.

  In order to solve these problems of improving writing quality and suppressing the generation of precipitates due to metal salts, a phosphate ester surfactant having an HLB of 13 or less excluding styrenated phenols and a chip body in the ink composition In order to suppress metal salt precipitates reacted with metal ions such as manganese ions and chromium ions eluted from the inside, it is important to use a phosphate ester surfactant having an HLB of 14 or more.

As described above, as the HLB value is larger, the number of hydrophilic ethylene oxides (CH ₂ CH ₂ O) is increased, so that the hydrophilicity is increased. In particular, a phosphate ester surfactant having an HLB of 14 or more. Is strongly hydrophilic and dissolves and stabilizes in an aqueous ink composition. Even if the phosphate ester surfactant of HLB13 or less reacts with metal ions to produce a metal salt having strong lipophilicity as described above, by adding a phosphate ester surfactant of HLB14 or more, This is because excessively hydrophilic ethylene oxide (CH ₂ CH ₂ O) is present to dissolve and stabilize a highly lipophilic metal salt.

［式中、Ｒはアルキル又はアルキルアリル基を、nはエチレンオキサイド付加モル数を、Ｒ’はＨまたはＲＯ（ＣＨ_２ＣＨ_２Ｏ）_ｎ基を示す。］ Further, the phosphoric acid ester surfactant includes polyoxyethylene alkyl ether or polyoxyethylene alkyl aryl ether phosphoric acid monoester, polyoxyethylene alkyl ether or polyoxyethylene alkyl aryl ether phosphoric acid diester, phosphoric acid triester, Alternatively, there are derivatives thereof, but these phosphate ester surfactants may be used alone or in admixture of two or more. Among them, in consideration of stability over time, a phosphoric acid ester surfactant represented by a general formula such as Chemical Formula 1 as a phosphoric acid monoester or phosphoric acid diester of polyoxyethylene alkyl ether or polyoxyethylene alkyl aryl ether Most preferably, is used.

[Wherein, R represents an alkyl or alkylallyl group, n represents the number of moles of ethylene oxide added, and R ′ represents H or a RO (CH ₂ CH ₂ O) _n group. ]

Moreover, as a specific example of the phosphate ester surfactant which is HLB13 or less represented by the general formula such as Chemical Formula 1, from the PRISURF series (Daiichi Kogyo Seiyaku Co., Ltd.), PRISURF A212C (HLB) Value 9, tridecyl alcohol), A210G (HLB value 9, octylphenol), A207H (HLB value 7, dinonylphenol), A208B (HLB value 6, lauryl alcohol), A208S (HLB value 7) Synthetic alcohol type), A208F (HLB value 9, short chain alcohol type), A212E (HLB value 10, nonylphenol type), A215C (HLB value 11, tridecyl alcohol type) and the like. Moreover, as a specific example of the phosphate ester surfactant which is HLB14 or more, from the PRISURF series (Daiichi Kogyo Seiyaku Co., Ltd.), A217E (HLB value 15, nonylphenol type) PRISURF A219B (HLB value) 16, lauryl alcohol type) and the like. These phosphate ester surfactants may be used alone or in admixture of two or more.
In addition, HLB can be calculated | required from HLB = 7 + 11.7log (Mw / Mo) and (Mw: molecular weight of a hydrophilic group, Mo: molecular weight of a lipophilic group) as a general formula.

  Among the types of phosphate ester surfactants, it is preferable to use a phosphate ester surfactant having a phenyl group. This is because the phosphate ester surfactant having a phenyl group has an effect of causing steric hindrance in the ink composition compared to other systems because the phenyl group forms a steric structure. By causing steric hindrance so that metal ions such as chromium ions do not react with the phosphate ester surfactant, there is an effect of suppressing metal salt precipitates. Furthermore, the use of a phosphate ester surfactant having a phenyl group having an HLB of 14 or more effectively suppresses metal salt precipitates due to an increase in hydrophilicity and a synergistic effect of steric hindrance. Therefore, even if it reacts and produces | generates a metal salt, it can be estimated that the further aggregation and growth can be suppressed. Specific examples of the phosphoric acid ester surfactant having a phenyl group include nonylphenol-based, dinonylphenol-based, and octylphenol-based surfactants.

  The amount of the phosphate ester surfactant having an HLB of 14 or more is preferably 0.1 to 3.0% by mass with respect to the total amount of the ink composition. When the addition amount is less than 0.1% by mass with respect to the total amount of the ink composition, it is difficult to obtain desired steric hindrance in the ink, and there is a possibility that precipitates due to metal salts may be generated. If it exceeds, the ink aging may become unstable, so 0.1 to 3.0% by mass with respect to the total amount of the ink composition. More preferably, 0.3-2.0 mass% is suitable with respect to the ink composition whole quantity.

  As for the addition amount of phosphate ester surfactant below HLB13, 0.1-3.0 mass% is desirable with respect to the ink composition whole quantity. If the addition amount is less than 0.1% by mass with respect to the total amount of the ink composition, the desired lubricity cannot be obtained, the writing quality is poor, and there is a risk of blurring in the handwriting. If it exceeds, the ink aging may become unstable, so 0.1 to 3.0% by mass with respect to the total amount of the ink composition. More preferably, 0.5-2.0 mass% is suitable with respect to the ink composition whole quantity.

  The ball material used in the present invention is not particularly limited, but when the ball is a cemented carbide material, as described above, when a phosphate ester surfactant and a metal chelating agent are added, the cemented carbide alloy The effect of the present invention that does not require a metal chelating agent is remarkable because cobalt and nickel, which are ball binding materials, react with the metal chelating agent to corrode cobalt, nickel and the like of the binding material over time. Furthermore, cemented carbide balls are less expensive than ceramic materials containing silicon carbide, alumina, zirconia, silicon nitride, etc., and the effect that ink is easy to be placed on the ball surface and good handwriting is easily obtained. Play.

  In the present invention, a resin may be used as an ink viscosity adjusting agent. Specific examples include water-soluble resins such as acrylic resins, alkyd resins, cellulose derivatives, polyvinyl pyrrolidone, and polyvinyl alcohol, shear thinning agents such as xanthan gum, cross-linked acrylic acid polymers, succinoglycans, and gar gums. It is done. You may use these individually or in mixture of 2 or more types.

  Moreover, if the addition amount of the resin is less than 0.1% by mass relative to the total amount of the ink composition, it is difficult to obtain a desired ink viscosity, and if it exceeds 30% by mass, the writing performance may be deteriorated. Therefore, 0.1 mass% or more and 30 mass% or less are preferable.

  The colorant is not particularly limited, and may 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. Specifically, carbon black, aniline black, ultramarine, yellow lead, titanium oxide, iron oxide, phthalocyanine, azo, quinacridone, quinophthalone, selenium , Triphenylmethane, perinone, perylene, glyoxazine, aluminum pigment, pearl pigment, fluorescent pigment, phosphorescent pigment, and complementary color pigment. In addition, a microcapsule pigment in which a colored body in which a pigment is dispersed in a medium as a colored resin particle body is encapsulated or solidified in a shell made of a resin wall film forming substance by a known microencapsulation method may be used. good. Further, colored resin particles in which the pigment is covered with a transparent or translucent resin or the like, or colored resin particles or colorless resin particles colored with a pigment or a dye can also be used. These dyes and pigments may be used alone or in combination of two or more. The addition amount is preferably 1% by mass to 20% by mass with respect to the total amount of the ink composition.

   In addition, as other additives, considering water dissolution stability, moisture evaporation drying prevention, etc., water-soluble organic solvents such as glycerin and ethylene glycol, pH adjusters such as triethanolamine, humectants such as urea and sorbit, A rust inhibitor such as benzotriazole, and a fungicide such as 1,2 benzoisothiazolin-3-one can be added. Silicone, acetylene glycol, and fluorine surfactants other than phosphate ester surfactants can also be added to improve wettability and water resistance. These can be used alone or in combination of two or more. It can also be blended.

Next, an Example is shown and this invention is demonstrated.
Example 1
The tip of the ink storage cylinder is equipped with a ballpoint pen tip that rotatably holds a cemented carbide ball having a ball diameter of φ0.7 mm in the ball holding chamber of the chip body made of stainless steel material. A refill directly filled with an ink composition 6 for water-based ballpoint pens and a grease-like ink follower 7 obtained by the following formulation 1 was used as a knock type gel ink ballpoint pen (trade name: G-Knock) manufactured by Pilot Corporation. ) To produce the aqueous ballpoint pen 1 of the present invention.

Next, an Example is shown and this invention is demonstrated.
Example 1
Water 61.05 parts by mass Water-soluble organic solvent (ethylene glycol) 20.0 parts by mass Phosphate ester surfactant (Plysurf A215C) 1.0 part by mass Phosphate ester surfactant (Plysurf A217E) 0.5 mass Part pH adjuster (triethanolamine) 1.5 parts by weight humectant (urea) 5.0 parts by weight humectant (Sorbit) 5.0 parts by weight antibacterial agent (1,2 benzoisothiazolin-3-one) 45 parts by mass rust inhibitor (benzotriazole) 0.5 parts by mass colorant (Acid Blue 9) 0.5 parts by mass colorant (Acid YELLOW 42) 4.5 parts by mass resin (xanthan gum) 0.4 parts by mass

  In Example 1, first, water, a water-soluble organic solvent, a phosphate ester surfactant (Plysurf A215C, Plysurf A217E (Daiichi Kogyo Seiyaku Co., Ltd.)), a pH adjuster, a moisturizer, a rust inhibitor, and a fungus A base ink is prepared by heating and stirring an agent and a colorant (Orient Chemical Co., Ltd.) with a magnetic hot stirrer.

  Thereafter, while heating the base ink prepared above, the resin (Sanchang Co., Ltd.) was added and thoroughly mixed and stirred until it became uniform using a homogenizer stirrer, and then a colorant was added. Stir until uniform. Then, it filtered using the filter paper and obtained the ink composition for water-based ball-point pens of the mixing example 1.

Ink viscosity in Examples and Comparative Examples was measured using a Brookfield DV-II viscometer (CPE-42 rotor) in a 20 ° C. environment at a shear rate of 1.92 sec ⁻¹ (rotation speed: 0.5 rpm), The ink viscosity was measured under two conditions of a shear rate of 384.0 sec ⁻¹ (rotation speed: 100 rpm).

Examples 2-8
A water-based ballpoint pen ink composition was prepared in the same procedure as ink formulation 1 except that each component was changed to a formulation as shown in Table 1, and the aqueous ballpoint pens of Examples 2 to 8 were prepared in the same manner as in Example 1. Got.

Comparative Examples 1-10
A water-based ballpoint pen ink composition was prepared in the same procedure as ink formulation 1 except that each component was changed to the formulation shown in Table 2, and the aqueous ballpoint pens of Comparative Examples 2 to 10 were obtained in the same manner as in Example 1. It was.

Tests and Evaluations The following tests and evaluations were performed using the aqueous ballpoint pens prepared in Examples 1 to 8 and Comparative Examples 1 to 10. The writing taste was evaluated using copy paper (PPC paper) as a writing test paper.

Written taste: A hand-written sensory test was performed and evaluated.
Smooth and good ・ ・ ・ ◎
Somewhat inferior
Heavy and inferior

Time-lapse test of chip body: After leaving the refill for a ballpoint pen in an environment of 50 ° C. and 0% humidity for 3 months at room temperature, the ink in the chip body was observed with a microscope.
Good without deposits ... ◎
Slightly generated precipitates, but no problem in practical use
Precipitates are generated and the practicality is poor.

Ball Corrosion Test: After the ballpoint pen refill was allowed to stand at room temperature for 3 months in an environment of 50 ° C. and humidity 0%, the corrosion state of the ball was observed with a microscope.
No corrosion of balls ... ○
Ball corrosion and poor practicality

    In Examples 1 to 8, the writing performance, the chip body aging test, and the ball corrosion test were good, or a performance with no practical problem was obtained.

  From the results in Table 2, in Comparative Examples 1, 3, and 4, no phosphate ester surfactant of HLB14 or higher was used, and therefore metal salt precipitates were generated in the chip body.

  In Comparative Examples 2, 5, 9, and 10, the phosphate ester surfactant having an HLB of 13 or less was not used, so the writing quality was poor.

  In Comparative Examples 6 and 7, since a surfactant other than the phosphate ester surfactant was used, the writing quality was poor, or metal salt deposits were generated in the chip body.

  In Comparative Example 8, a phosphate surfactant having an HLB of 14 or more was not used, but since ethylenediaminetetraacetic acid (EDTA) was added as a precipitate inhibitor, no metal salt precipitate was generated in the chip body. However, since ethylenediaminetetraacetic acid (EDTA) is highly reactive, corrosion of the ball, which is a cemented carbide material, occurred and writing quality was poor.

  Although not shown, when a coil spring that presses a ball made of stainless steel is disposed in the ballpoint pen tip, the phosphate ester surfactant and the metal ions of the coil spring are disposed in the same manner as the tip body. Since the metal salt may be generated by this reaction, the effect of the present invention is remarkable.

Furthermore, in the ink composition to which a large particle size such as a pigment is added, the writing quality may be deteriorated due to rotation inhibition between the ball and the chip body, and a ball having a ball diameter of 0.7 mm or less was used. Since the ball pen has a small contact area between the ball and the ball seat, and there is a possibility that the writing quality is deteriorated due to a high load applied to the unit area, the effect of the present invention is remarkable.

The present invention relates to a water-based ballpoint pen, and more specifically, in a ballpoint pen tip using a tip body made of a stainless steel material, comprising a phosphate ester surfactant having a different HLB excluding styrenated phenol, and the phosphate ester surfactant The agent contains at least a phosphate ester surfactant with an HLB of 13 or less and a phosphate ester surfactant with an HLB of 14 or more, so that the writing quality is good and the metal salt in the ballpoint pen tip is suppressed. By doing so, it is possible to provide an aqueous ballpoint pen having excellent stability over time. Therefore, it can be widely used as a ballpoint pen, such as a cap type and a knock type.

It is a longitudinal cross-sectional view which shows the water-based ball-point pen of this invention. It is an external view in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Water-based ball-point pen 2 Ink storage cylinder 3 Ball-point pen tip 4 Ball 5 Tip holder 6 Water-based ball-point pen ink composition 7 Ink follower

Claims (7)

A water-based ballpoint pen comprising a ballpoint pen tip that rotatably holds a ball in a ball holding chamber of a tip body made of a stainless steel material, directly or via a tip holder, at the tip of an ink containing cylinder, In the ink container, at least water, a colorant, and a phosphate ester surfactant having a different HLB excluding styrenated phenol, and the phosphate ester surfactant has a HLB of 13 or less. And an aqueous ballpoint pen ink composition comprising at least a phosphate ester surfactant having an HLB of 14 or more. The phosphate ester surfactant having an HLB of 13 or less and the phosphate ester surfactant having an HLB of 14 or more are nonylphenol, lauryl alcohol, tridecyl alcohol, short chain alcohol, dinonylphenol, octylphenol. The water-based ballpoint pen according to claim 1, wherein the water-based ballpoint pen is selected from phosphoric acid ester surfactants based on synthetic or synthetic alcohols. The aqueous ballpoint pen according to claim 1 or 2, wherein the phosphate ester surfactant is a phosphate ester surfactant represented by the following general formula (Formula 1).

[Wherein, R represents an alkyl or alkylallyl group, n represents the number of moles of ethylene oxide added, and R ′ represents H or a RO (CH ₂ CH ₂ O) _n group. ] The aqueous ballpoint pen according to any one of claims 1 to 3, wherein the phosphate ester surfactant having an HLB of 14 or more is a phosphate ester surfactant having a phenyl group. The phosphate surfactant having an HLB of 14 or more is 0.1% by mass or more and 3.0% by mass or less based on the total mass of the ink composition. 2. A water-based ballpoint pen according to item 1. The phosphate surfactant having an HLB of 13 or less is 0.1% by mass or more and 3.0% by mass or less based on the total mass of the ink composition. 2. A water-based ballpoint pen according to item 1. The water-based ballpoint pen according to any one of claims 1 to 6, wherein the ball is made of a cemented carbide material.

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