JP2016124179A - Water-based ballpoint pen - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a water-based ballpoint pen which suppresses leakage of ink, is excellent in suppression of wearing of a ball seat, and makes handwriting dense.SOLUTION: In a water-based ballpoint pen, a ballpoint pen tip which rotatably holds a ball is mounted directly or through a tip holder on the tip of an ink-housing tube, and the ink-housing tube houses an ink composition for water-based ballpoint pen including at least water, a colorant, organic resin particles, and a shear viscosity reduction-imparting agent in the inside thereof. The moving amount in the axial direction of the ball of the ballpoint pen tip is 15 μm or more, and an average particle size of the organic resin particles is 15 μm or less.SELECTED DRAWING: None

Description

  The present invention relates to a water-based ballpoint pen, and more particularly to a water-based ballpoint pen that is excellent in suppressing ink leakage and suppressing wear on a ball seat, resulting in a dark handwriting.

  As an ink composition for a ballpoint pen used in a conventional ballpoint pen, as Patent Document 1, Patent No. 3338222, “Direct liquid knock type water-based ballpoint pen ink”, improving the moisture retention and leaving the pen without a cap, As a direct liquid knock type water-based ballpoint pen ink that does not cause a direct current phenomenon that ink is blown out or hangs down from the nib, or Japanese Patent Publication No. 6-47661 “Ball pen ink composition” Discloses a ballpoint pen ink having an ink viscosity of 50 to 2000 cps.

“Patent No. 3338222” Japanese Patent Publication No. 6-47661

  However, when these inks for water-based ballpoint pens are used as a retractable ballpoint pen or a cap-off ballpoint pen, there is a risk that ink dripping may occur due to ink leakage from the tip of the tip when the ballpoint pen is in a downward state. It was.

  By the way, with respect to the ballpoint pen displayed in the display case, the user takes out the ballpoint pen from the display case, and returns the ballpoint pen to the display case after confirming test writing or knocking operation.

  At this time, in the case of a cap-off ballpoint pen such as a retractable ballpoint pen, when it is returned to the display case with the ballpoint pen tip protruded, it comes into contact with the bottom of the ballpoint pen display case. . As such, while repeatedly returning the test pens to the display case, a number of ball pens were stacked on the ball pen that was returned first, and as a result, a plurality of the ball pens stacked. Because of the weight, the ball receives a shock when the tip of the ballpoint pen tip comes into contact with the bottom of the ballpoint pen display case and moves toward the bottom wall of the ball holding chamber, so there is a gap between the ball and the inner wall of the tip of the tip. Ink drops from the gap, ink leakage occurs, the display case is soiled, and the ballpoint pens in other cases are also soiled.

  In order to solve the ink leakage described above, if the ink viscosity is increased as a method for dealing with ink, the ink consumption is reduced, a dark handwriting cannot be obtained, and the writing quality at the time of writing is also inferior. In addition, as a method for dealing with the chip, by using a coil spring or the like in the chip body, the ball is constantly pressed against the inner wall surface at the tip of the chip, and the minute gap between the ball and the tip of the chip is closed to suppress ink dripping. However, there are also problems that the manufacturing cost is increased, the rotation of the ball is easily deteriorated, and the writing quality is easily affected.

  An object of the present invention is to provide a water-based ballpoint pen that suppresses ink leakage, is excellent in suppressing wear of a ball seat, and has a dark handwriting.

In order to solve the above problems, the present invention
“1. A ballpoint pen tip holding a ball rotatably at the tip of the ink container is mounted directly or via a chip holder, and at least water, colorant, organic resin particles, shear thinning viscosity is contained in the ink container. An aqueous ballpoint pen containing an ink composition for an aqueous ballpoint pen comprising an imparting agent, wherein the amount of movement of the ballpoint tip in the axial direction of the ball is 15 μm or more, and the average particle diameter of the organic resin particles is 15 μm or less. A water-based ballpoint pen.
2. 2. The water-based ballpoint pen according to item 1, wherein the organic resin particles are olefin resin particles and / or nitrogen-containing resin particles.
3. The water-based ballpoint pen according to Item 1 or 2, wherein the ink composition of the water-based ballpoint pen has an ink viscosity of 1000 to 5000 mPa · s at 20 ° C. and a shear rate of 1.92 sec ⁻¹ .
4). The water-based ballpoint pen according to any one of Items 1 to 3, wherein the colorant is pigment particles having an average particle diameter of 1 μm or less.
5). Any one of Items 1 to 4, wherein when the average particle diameter of the organic resin particles is X μm and the average particle diameter of the pigment particles is Y μm, Y / X <2.0. The water-based ballpoint pen described in 1.
6). 6. The water-based ballpoint pen according to any one of items 1 to 5, wherein the water-based ballpoint pen ink composition contains dextrin.
7). The water-based ballpoint pen ink composition contains a water-soluble solvent, and the content is 0.1 to 10% by mass based on the total amount of the ink composition. The water-based ballpoint pen described in the item.
8). 8. The water-based ballpoint pen according to any one of items 1 to 7, wherein the ink composition for water-based ballpoint pens contains a phosphate ester surfactant.
9. The water-based ballpoint pen is a retractable water-based ballpoint pen that is slidably disposed in a shaft cylinder, and a tip end portion of the ballpoint pen tip can protrude and retract from the tip end portion of the shaft cylinder. The water-based ballpoint pen according to any one of Items 8 to 9. "

  The present invention returns the ballpoint pen to the display case with the ballpoint pen tip protruded, and suppresses the leakage of ink and the wear of the ball seat even if there is a gap between the ball and the inner wall of the tip end. It was possible to provide a water-based ballpoint pen with a dark handwriting.

  A feature of the present invention is that a ballpoint pen tip holding a ball rotatably held at the tip of the ink containing cylinder is mounted directly or via a chip holder, and at least water, a colorant, organic resin particles, An aqueous ballpoint pen containing an aqueous ballpoint pen ink composition comprising a shear thinning agent, wherein the ball pen tip moves in the axial direction of the ball at least 15 μm, and the average particle size of the organic resin particles is 15 μm. The water-based ballpoint pen is characterized by being m or less.

  In the present invention, in order to obtain a dark handwriting, it is necessary to increase the ink ejection amount by setting the movement amount of the ball-point pen tip in the axial direction of the ball to 15 μm or more. However, simply increasing the amount of ink discharged has the problem of causing ink leakage (ink dripping) from the gap between the ball and the inner wall of the tip of the tip. By increasing the viscosity, ink leakage could be suppressed to some extent, but it was not at a level that could be sufficiently suppressed.

  Therefore, in the present invention, by containing particles having an average particle diameter of 15 μm or less, it is possible to cause a physical failure in the gap between the ball and the inner wall of the tip end of the chip, thereby suppressing ink leakage. In addition, since the hardness is lower than that of inorganic particles, the particles are partially deformed, etc., and are brought into close contact with each other, resulting in a structure formed by weak aggregation. By forming a structure with high resistance to leakage in ink, it is possible to suppress ink leakage. On the other hand, because the structure is formed by weak agglomeration, the agglomerated structure is crushed by physical action such as ball rotation during writing, so write well without disturbing ink fluidity during writing. It is possible to obtain a dark handwriting. In addition, organic resin particles with an average particle size of 15 μm or less enter between the ball and the ball seat, making it difficult to make direct contact. Therefore, it is possible to reduce ball rotation resistance and suppress wear of the ball seat. It is. Therefore, it is important to contain organic resin particles having an average particle diameter of 15 μm or less.

  Also, if the ball pen tip movement amount in the axial direction of the ball exceeds 50 μm, it is difficult to suppress ink leakage, so it is preferably 15 to 50 μm, and the ink ejection amount is increased to improve the ball seat wear suppression. In order to make it easy to make a dark handwriting, 20 μm or more is preferable, so 20 to 50 μm is preferable, and further considering it, 25 to 45 μm is preferable. The movement amount (clearance) of the ball-point pen tip in the axial direction of the ball indicates the distance that the ball can move in the vertical-axis direction of the ball-point pen tip body.

  Furthermore, the nitrogen-containing resin particles are more stable than other organic resin particles themselves, and are more likely to have an agglomerated structure for a long period of time, and it is easy to stably suppress ink leakage. Among them, it is preferable to use nitrogen-containing resin particles having a cross-linked structure because they are stable without absorbing moisture in water-based ink and have excellent temporal stability.

   For organic resin particles with an average particle size of 15 μm or less, olefin resin particles such as polyethylene resin and polypropylene resin, melamine / formaldehyde resin, benzoguanamine / formaldehyde resin, benzoguanamine / melamine / formaldehyde resin, urea formaldehyde resin, nylon resin Examples thereof include nitrogen-containing resin particles containing nitrogen atoms in the chemical structure, acrylic resin particles, styrene resin particles, epoxy resin particles, urethane resin particles, cellulose resin particles, and the like. These organic resin particles may be used alone or in combination of two or more.

  Among these, olefin resin particles and nitrogen-containing resin particles are preferably used. This is an olefin-based resin particle that is a hydrocarbon compound and is nonpolar so that it easily aggregates in water and is optimized so as not to cause problems such as insufficient ink discharge while suppressing ink leakage. It is presumed that it is easy to form an aggregated structure. Furthermore, since the olefin resin particles have a high melting temperature, they tend to exist stably even in a high temperature environment, and when they are in a high pressure environment, they are easy to deform and difficult to modify. Since it is stable even if it is sandwiched between the ball and the ball seat, it can be suitably used as an ink additive for suppressing wear of the ball seat. In addition, the nitrogen-containing resin particles are more stable than other organic resin particles, and the nitrogen-containing resin particles are easy to take an agglomerated structure for a long period of time and stably suppress ink leakage. Among them, it is preferable to use nitrogen-containing resin particles having a cross-linked structure because they are stable without absorbing moisture in water-based ink and have excellent temporal stability.

  Further, the average particle size of the organic resin particles is preferably 10 μm or less, more preferably 6 μm or less because the smaller the average particle size, the more easily adhere to each other and form a weak aggregate structure and easily suppress ink leakage. The following is preferable, and considering that the rotational resistance of the ball is relaxed and the wear of the ball seat is suppressed, the average particle size is preferably 3 μm or less. The average particle diameter is determined by a volume standard method using a laser diffraction method (manufactured by MICROTRAC9320-X100 Honeywell).

    The organic resin particles are specifically Nopco PEN-17 (polyolefin resin, average particle size 0.01 μm), Nopcomal MS40 (polyethylene resin, average particle size 1.0 μm) (manufactured by San Nopco Co., Ltd.) ), CERAFLOUR 950 (modified polyethylene resin, average particle size 9 μm), 925 (modified polyethylene resin, average particle size 6 μm), 929 (modified polyethylene resin, average particle size 8 μm) (BYK Co., Ltd.), Chemipearl M200 ( Low molecular weight polyethylene dispersion, average particle size 6 μm), W300 (low density polyethylene dispersion, average particle size 3 μm), W900 (low density PE dispersion, average particle size 0.6 μm) (Mitsui Chemicals, Inc.) Manufactured), Eposter S6 (melamine / formaldehyde condensation particles, average particle size 0.3 to 0.6 μm) S (melamine / formaldehyde condensation particles, average particle size 0.1 to 0.3 μm), S12 (melamine / formaldehyde condensation particles, average particle size 1 to 2 μm), MS (benzoguanamine / formaldehyde condensation particles, average particle size) 1 to 3 μm), M30 (benzoguanamine / melamine / formaldehyde condensation particles, average particle size 2.5 to 4 μm) (manufactured by Nippon Shokubai Co., Ltd.), nylon SP-500 (nylon resin, average particle size 5 μm) (( Manufactured by Toray Industries, Inc.), Orgasol 2001-UD-NAT-1 (nylon resin, average particle size 5 μm), 2001-EXD-NAT-1 (nylon resin, average particle size 10 μm), 3501-EXD-NAT-1 ( Nylon resin, average particle size 10 μm (made by Arkema Co., Ltd.), MW-330 (nylon resin, average particle size 7 μm) (Sumika Environmental Co., Ltd.) FS-102 (average particle size 0.1 μm, styrene / acrylic resin), FS-106 (average particle size 0.1 μm, acrylic resin), FS-107 (average particle size 0.1 μm) , Acrylic resin), FS-201 (average particle size 0.5 μm, styrene / acrylic resin), FS-301 (average particle size 1.0 μm, styrene / acrylic resin), FS-501 (average particle size 0.5 μm, Acrylic resin), FS-701 (average particle size 0.1 μm, fluorine-based acrylic resin), MG-351 (average particle size 1.0 μm, styrene / acrylic resin) (manufactured by Nippon Paint Co., Ltd.), and the like. .

  Moreover, about content of the said organic resin particle, 0.1-10.0 mass% is more preferable with respect to the ink composition whole quantity. This is because it is difficult to suppress ink leakage when the content of the organic resin particles is less than 0.1% by mass, and when the content exceeds 10.0% by mass, the agglomeration structure tends to become strong, and writing quality and dry-up performance are improved. It is because it is easy to be affected. Furthermore, if considered further, 0.1-5.0 mass% is preferable, Most preferably, 0.3-3.0 mass% is preferable.

As for the ink viscosity, the shear viscosity is 1.92 sec ⁻¹ in an environment of 20 ° C., and the ink viscosity is preferably 1000 to 5000 mPa · s. If the ink viscosity is less than 1000 mPa · s, the ink viscosity is low. This is because it is difficult to suppress ink leakage and if it exceeds 5000 mPa · s, wear suppression of the ball seat and writing quality tend to be inferior, ink discharge amount is small, and dark handwriting is difficult to obtain. Considering more, 1500 to 3500 mPa · s is preferable.

  In addition, a shear thinning agent is used as the ink viscosity adjusting agent. Examples of the shear thinning agent include cross-linked acrylic acid polymers, xanthan gum, welan gum, succinoglycan, guar gum, locust bean gum, λ-carrageenan, and cellulose. A derivative | guide_body, a diutane gum, etc. are mentioned, These shear thinning agents may be used individually or in combination of 2 or more types.

  The colorant used in the present invention is not particularly limited, and examples of the pigment include inorganic, organic, processed pigments, and the like. Specifically, carbon black, aniline black, ultramarine, yellow lead, titanium oxide, iron oxide, Examples include phthalocyanine, azo, quinacridone, quinophthalone, selenium, triphenylmethane, perinone, perylene, glyoxazine, microcapsules, aluminum pigments, pearl pigments, fluorescent pigments, phosphorescent pigments, and complementary color pigments. . As the dye, direct dyes, acid dyes, basic dyes, metal-containing dyes, various salt-forming dyes, and the like can be used. These pigments and dyes may be used alone or in combination of two or more.

Among these colorants, it is preferable to use pigment particles having an average particle diameter of 1 μm or less. This is because, when using organic resin particles having an average particle diameter of 15 μm or less as in the present invention, when the organic resin particles are in close contact with each other, a gap is generated between the organic resin particles, which causes ink leakage. This is because the effect of suppressing ink leakage can be more easily obtained by filling the gaps with pigment particles having an average particle size of 1 μm or less. Pigment particles having a diameter of 5 μm or less are preferred. Furthermore, as for the shape of the pigment particles, spherical or irregular shapes can be used, but in consideration of reducing the frictional resistance, spherical pigment particles are preferable, and more preferably spherical pigment resin particles. is there. The spherical pigment particles here are not limited to true spheres, and may be substantially spherical pigment particles, substantially elliptical pigment particles, or the like.
The average particle diameter of the pigment particles is determined by a volume reference method using a laser diffraction method (MICROTRAC9320-X100 manufactured by Honeywell).

  Further, when the average particle diameter of the organic resin particles is X μm and the average particle diameter of the pigment particles is Y μm, it is preferable that the relationship of Y / X <2.0 is satisfied. This is because when close contact occurs and a gap is generated between the organic resin particles, it is difficult to fill the gap and ink leakage is likely to be affected. In consideration, Y / X <1.5 is preferable, and 0.05 <Y / X <1.0 is most preferable.

  Moreover, in order to suppress ink leakage, it is preferable to use dextrin. This is because dextrin is used to form a film when the ink at the nib is dry. This is because the effect of suppressing ink leakage from the gap is obtained.

  Moreover, about the weight average molecular weight of dextrin, 5000-120,000 are more preferable. When the weight average molecular weight exceeds 120,000, the film formed on the pen tip is hard, and there is a tendency for handwriting to be easily blurred during writing at the time of dry-up. On the other hand, when the weight average molecular weight is less than 5,000, hygroscopicity is increased. This is because the film tends to be soft on the pen tip and the ink leakage suppressing effect tends to be difficult to obtain. Furthermore, when the weight average molecular weight is smaller than 20000, the film tends to be thin, and the weight average molecular weight is most preferably 20000 to 120,000.

  The content of dextrin is preferably 0.1 to 5.0% by mass with respect to the total amount of the ink composition. This is because if the amount is less than 0.1% by mass, the effect of ink leakage tends to be insufficient, and if it exceeds 5.0% by mass, it tends to be difficult to dissolve in the ink. If considering the solubility in the ink more, 0.1 to 3.0% by mass is preferable, and considering the ink leakage more, 1.0 to 3.0% by mass is most preferable.

  A water-soluble solvent is used in consideration of water dissolution stability, prevention of water evaporation and drying. Polyhydric alcohol solvents such as ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, polyethylene glycol, glycerin, methanol, ethanol, 1-propanol, 2-propanol, isopropanol, isobutanol, t-butanol, allyl alcohol, 3-methyl -1-butyn-3-ol, alcohol solvents such as ethylene glycol monomethyl ether acetate and other higher alcohols, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, 3-methoxybutanol, 3-methoxy-3-methylbutanol And glycol ether solvents such as Among them, it is preferable to use a polyhydric alcohol solvent in view of dissolution stability with the organic resin particles used in the present invention. The polyhydric alcohol solvent is a solvent in which two or more hydroxyl groups are bonded to different carbon atoms of an aliphatic or alicyclic compound, and among them, a polyhydric alcohol having a divalent or trivalent hydroxyl group. It is most preferable to contain at least. You may use these individually or in mixture of 2 or more types.

  The content of the water-soluble solvent is preferably 0.1 to 25.0% by mass with respect to the total amount of the ink composition in consideration of solubility, ink leakage, bleeding, etc., but ink leakage is considered as in the present invention. In this case, 10.0% by mass or less is preferable. This is because the agglomeration structure is easily broken by hydrogen bonding with a solvent, and the effect of suppressing ink leakage by the organic resin particles is easily affected. Less than mass% is preferable.

    Also, use phosphate ester surfactants, fatty acid salts, etc. in order to improve lubricity and smoothen the rotation of the ball, thereby making it easier to suppress wear of the ball seat and improve writing quality. Is preferred. In particular, it is preferable to use a phosphate ester-based surfactant having a phosphate group. This is because the phosphate group is adsorbed to the metal, thereby improving the lubricity and making it easier to suppress wear of the ball seat and improve the writing quality. Examples of the phosphate ester surfactant include styrenated phenols, nonylphenols, lauryl alcohols, tridecyl alcohols, octylphenols, hexanols, and the like. Among these, since having a phenyl skeleton tends to affect lubricity due to steric hindrance, it is preferable to use a phosphate ester-based surfactant having no phenyl skeleton. You may use these individually or in mixture of 2 or more types.

  In addition, specific examples of the phosphate ester-based surfactant include Prisurf A212C (tridecyl alcohol), A208B (lauryl alcohol), and the like from the Prisurf series (Daiichi Kogyo Seiyaku Co., Ltd.). A213B (lauryl alcohol type), A208F (short chain alcohol type), A215C (tridecyl alcohol type), A219B (lauryl alcohol type), and the like. Specific examples of the fatty acid salt include OS soap, NS soap, FR-14, FR-25 (Kao Corporation) and the like. These phosphate ester surfactants and fatty acid salts may be used alone or in combination of two or more.

In order to obtain a darker handwriting using pigment particles, one or more surfactants selected from silicone surfactants, acetylene glycol surfactants, fluorine surfactants, and dialkylsulfosuccinates are used. It is preferable. This is because the pigment particles remain on the paper surface due to improved permeability to paper, and a darker and clearer handwriting can be easily obtained. Therefore, the ball pen tip movement amount in the axial direction of the ball is 15 μm.
When m is equal to or greater than m and the amount of ink discharged is increased and the surfactant is used, a darker and clearer handwriting can be easily obtained. Among them, it is preferable to use a fluorosurfactant. This is because the fluorosurfactant can most reduce the surface tension and easily improve the permeability to paper. It is because it is easy to obtain.

  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 perfluoroalkyl ethylene oxide adduct. This is because a fluorosurfactant of a perfluoroalkylethylene oxide adduct can be preferably used because it can easily become darker handwriting. Furthermore, if an ethylene oxide group is present, the hydrophilicity becomes strong, so that it is easy to dissolve in water and the stability over time tends to be stable. You may use these individually or in mixture of 2 or more types.

  Other additives may contain additives as desired, specifically, pH adjusters, acrylic resin emulsions, urethane resin emulsions for improving the colorant stability over time and further lubricity. , Fixing agents such as styrene-butadiene resin emulsion, pigment dispersants such as acidic resin, antibacterial agents such as 1,2-benzisothiazolin-3-one, moisturizers such as urea and sorbit, rust prevention such as benzotriazole Agents, chelating agents such as ethylenediaminetetraacetic acid, 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
20.0 parts by mass of pigment dispersion (colored resin particles: average particle size 0.4 μm, solid content 30%)
58.7 parts by weight of water
Organic resin particles (Eposter S6, average particle size 0.6 μm) 1.0 part by mass
Polyhydric alcohol (glycerin) 10.0 parts by mass
Dextrin (weight average molecular weight: 100,000) 1.0 part by mass
Urea 5.0 parts by mass
pH adjuster (triethanolamine) 2.0 parts by mass
0.5 parts by mass of ethylenediaminetetraacetic acid (EDTA)
Lubricant (phosphate ester surfactant) 1.0 part by mass
Rust preventive (benzotriazole) 0.5 parts by mass
Shear thinning agent (succinoglycan) 0.3 parts by mass

A base ink was prepared by heating and stirring the pigment dispersion, water, organic resin particles, polyhydric alcohol solvent, dextrin, urea, pH adjuster, ethylenediaminetetraacetic acid, lubricant, and rust inhibitor with a magnetic hot stirrer.

Thereafter, while heating the base ink prepared above, a shear thinning agent was added, and the mixture was sufficiently mixed and stirred using a homogenizer stirrer until a uniform state was obtained. Got.
The ink viscosity of Example 1 was measured using a Brookfield DV-II viscometer (CPE-42 rotor) at a shear rate of 1.92 sec ⁻¹ (rotation speed 0.5 rpm) in an environment of 20 ° C. When the ink viscosity was measured under the conditions, it was 1600 mPa · s.

Examples 2-24
Except for changing the ink formulation as shown in the table, water-based ballpoint pen ink compositions of Examples 2 to 24 were obtained in the same procedure as Example 1. The table shows the ink formulation and evaluation results.

Comparative Examples 1-7
Except for changing the ink formulation as shown in the table, aqueous ballpoint pen ink compositions of Comparative Examples 1 to 7 were obtained in the same procedure as in Example 1. The table shows the ink formulation and evaluation results.

Testing and evaluation
A ballpoint pen tip (ball of a ballpoint pen tip) in which the ink composition for water-based ballpoint pens prepared in Examples 1 to 24 and Comparative Examples 1 to 7 was rotatably held by a ball having a ball diameter of 0.7 mm at the tip of the ink containing cylinder. A refill (1.0 g) filled in an ink containing cylinder (made of polypropylene) having a movement amount of 30 μm in the axial direction through a chip holder is a gel ink ballpoint pen (trade name: G) manufactured by Pilot Corporation. The following tests and evaluations were performed. In addition, the abrasion resistance test (ball seat wear suppression) and the evaluation of the darkness of the handwriting were evaluated by the following test method using JIS P3201 writing paper A as a writing test paper.

Ink leakage test: A 40 g weight is attached to a gel ink ballpoint pen, and the ballpoint pen tip protrudes downward, keeping the ballpoint pen tip ball in contact with the bottom of the ballpoint pen display case, 20 ° C., 65% RH The ink leakage from the tip of the ballpoint pen tip was measured.
The amount of ink leakage is less than 5 mg.
Ink leakage amount of 5 to 15 mg
Ink leakage exceeding 15 mg and less than 30 mg
Ink leakage amount of 30mg or more ・ ・ ・ ×

Abrasion resistance test: The wear of the ball seat after the writing test was measured with a running test machine with a load of 100 gf, a writing angle of 65 °, and 4 m / min.
Ball seat wear less than 10μm ・ ・ ・ ◎
Ball seat wear of 10 to 20 μm
Ball seat wear exceeding 20-30 μm
Ball seat wear exceeding 30 μm ・ ・ ・ ×

Handwriting density: Handwriting written by handwriting was observed.
Thick and clear handwriting
What is a dark handwriting
A handwriting with a darkness that has no practical problem ・ ・ ・ △
Thin handwriting ・ ・ ・ ×

Written taste: A hand-written sensory test was performed and evaluated.
Very smooth ・ ・ ・ ◎
What is smooth ・ ・ ・ ○
Smoothness of a level that is not a problem for practical use ・ ・ ・ △
Heavy thing

  From the result of a table | surface, in Examples 1-24, the ink leak test, the abrasion resistance test, the density of the handwriting, and the performance of a favorable level were obtained. In addition, when the ink composition for water-based ballpoint pens of Examples 1 to 24 was used and tested with a gel ink ballpoint pen that was changed to a ballpoint pen tip specification that does not have a resilient member such as a coil spring, an ink leakage test, an abrasion resistance test, and a handwriting A good level of performance was obtained in both darkness and writing quality.

  Furthermore, using the ink composition for water-based ballpoint pens of Examples 1 to 24, a gel ink ballpoint pen whose ball diameter was changed to 1.0 mm was tested with a gel ink ballpoint pen. A good level of performance was obtained for both the writing quality and the writing quality. Therefore, when a ball having a ball diameter of 0.9 mm or more is used and the ink discharge amount is increased, a gap is large between the ball and the inner wall of the tip end of the chip, and ink leakage is likely to occur. This effect is remarkable and is preferably used.

  From the result of Table 3, since the organic resin particle was not used in Comparative Examples 1 and 4 to 6, the ink leakage was severe, which was a practically problematic level.

  In Comparative Examples 2 and 3, since the movement amount of the ball of the ball-point pen tip in the axial direction was less than 15 μm, the ink discharge amount was reduced, resulting in thin handwriting.

  Comparative Example 7 was an organic resin particle having an average particle diameter of more than 15 μm, so that it was a practically problematic level.

  In general, a ballpoint pen tip of a water-based gel ballpoint pen has a ball held at the tip of the ballpoint pen tip so as to suppress ink leakage. It has a valve mechanism that presses against the inner wall and creates a gap between the inner wall of the tip edge of the tip and the ball by the pressing force at the time of writing and allows the ink to flow out, and the minute gap at the tip end is also closed when not in use. When the ink composition for a ballpoint pen that has a particularly high effect of suppressing the leakage of ink as in the invention is used, ink leakage can be suppressed without a resilient member such as the coil spring. Therefore, the resistance of the ball and the elastic member is eliminated, the writing quality is improved, the ink fluidity is improved, the ink followability is improved, the number of parts is further reduced, and the cost can be suppressed. And is more effective. In particular, in a pen-type ballpoint pen, since suppression of ink leakage is more important, it can be suitably used.

  The present invention can be used as an ink composition for water-based ballpoint pens. More specifically, the present invention can be widely used as cap-type, retractable ballpoint pens, markers, fountain pens, and the like filled with the water-based ballpoint pen ink composition. it can.

Claims (9)

A ballpoint pen tip holding a ball rotatably at the tip of the ink containing cylinder is mounted directly or via a chip holder, and at least water, colorant, organic resin particles, and shear thinning agent are added to the ink containing cylinder. A water-based ballpoint pen containing a water-based ballpoint pen ink composition, wherein the ball pen tip has a movement amount in the axial direction of the ball of 15 μm or more, and the average particle size of the organic resin particles is 15 μm or less. A water-based ballpoint pen. The aqueous ballpoint pen according to claim 1, wherein the organic resin particles are olefin resin particles and / or nitrogen-containing resin particles. 3. The water-based ballpoint pen according to claim 1, wherein the ink viscosity of the water-based ballpoint pen ink is 1000 to 5000 mPa · s at 20 ° C. and a shear rate of 1.92 sec ⁻¹ . The water-based ballpoint pen according to any one of claims 1 to 3, wherein the colorant is pigment particles having an average particle diameter of 1 µm or less. The average particle diameter of the organic resin particles is X μm, and the average particle diameter of the pigment particles is Y μm, and Y / X <2.0. Water-based ballpoint pen. The water-based ballpoint pen according to any one of claims 1 to 5, wherein the ink composition for water-based ballpoint pen contains dextrin. The water-based ballpoint pen ink composition contains a water-soluble solvent, and the content is 0.1 to 10% by mass based on the total amount of the ink composition. The water-based ballpoint pen described. The water-based ballpoint pen according to any one of claims 1 to 7, wherein the water-based ballpoint pen ink composition contains a phosphate ester-based surfactant. 2. A retractable water-based ballpoint pen, wherein the water-based ballpoint pen is slidably disposed in a shaft cylinder, and a tip end portion of the ballpoint pen tip can be projected and retracted from the tip end portion of the shaft cylinder. 9. The water-based ballpoint pen according to any one of 8 above.