JP3379849B2 - Aqueous ballpoint pen - Google Patents

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to an aqueous ballpoint pen. More specifically, the present invention relates to a water-based ballpoint pen that directly fills an ink cylinder with ink and supplies the ink directly to a ballpoint pen tip without using an ink occlusion body, an ink induction core, and a pen core.

[0002]

2. Description of the Related Art A water-based ballpoint pen is roughly classified into (a) a ballpoint pen tip through which ink impregnated in an ink occlusion body arranged in the ink barrel is passed through an ink induction core arranged between the ink barrel and the ballpoint pen tip. Supplied to (b)
Ink directly filled in the ink cylinder is supplied to the ballpoint pen tip through a pen core and an ink induction core arranged between the ink cylinder and the ballpoint pen tip, and (c)
There is one that directly fills the ink into the ink cylinder and directly supplies the ink to the ball-point pen tip without using the ink occlusion body, the ink induction core, and the pen core.

[0003]

The type (c) described above has an advantage that the amount of ink stored can be increased and all the ink can be used. However, the structure as described above prevents ink leakage. Therefore, when the ball-point pen is stationary, that is, when not in use, the ink is made to have a high viscosity to prevent ink leakage from the ball-point pen tip, and when used, the ball of the ball-point pen tip gives a shearing force to the ink to make it a low-viscosity state. Ink needs to flow out of the ballpoint pen tip. In addition, even if the environment such as temperature and humidity changes, it is required to have a strict performance of preventing the ink from dripping when the ballpoint pen tip is left facing downward. It is also required that the handwriting has high contrast and that the handwriting has high contrast for a long time. Various proposals have been made so far in order to satisfy each of the above conditions,
It has not yet been possible to satisfy all of the above conditions. For example, there has been proposed a writing utensil ink in which thixotropic properties are imparted to the ink by using a crosslinked acrylic acid resin (Japanese Patent Laid-Open No. 57-49678). There is a drawback in that it is impossible to prevent the ink from dripping from the chip when left standing. An object of the present invention is to provide a ball-point pen directly filled with ink that satisfies the above-mentioned conditions, and particularly a ball-point pen excellent in ink drooling prevention performance.

[0004]

As a result of intensive studies, the present inventors have used a specific cross-linkable hydrophilic polymer swollen in an ink and dispersed in a gel form, and It was found that the object can be achieved by a synergistic effect by combining an ink having a particle size in a specific range and a ballpoint pen tip having a clearance between the ball and the ball receiver in a specific range, and based on this finding, the present invention Was completed.

That is, the present invention relates to "1. (A) a. Aqueous medium, b. Pigment and
c. 0.5 mol% with respect to the total amount of the copolymerizable monoethylenic monomer which is swollen to form particles having a particle size of 0.5 to 10.0 μm and dispersed in a gel state, which is optionally used in combination with the carboxyl group-containing monomer. A water-based ink comprising a carboxyl group-containing crosslinkable hydrophilic polymer crosslinked with the above-mentioned crosslinking monomer having at least two polymerizable unsaturated groups, and (B) the clearance between the ball and the ball receiver is 10 A water-based ballpoint pen directly packed in an ink cylinder equipped with a ballpoint pen tip in the range of 0 to 40.0 μm. 2. An ink containing 5 to 90% by weight of water, 0 to 50% by weight of a moisturizing agent, 1 to 50% by weight of a pigment, and 0.1 to 2.0% by weight of a crosslinkable hydrophilic polymer containing a carboxyl group was used.
The water-based ballpoint pen described in the item. 3. The water-based ballpoint pen according to item 1 or 2, which uses an ink having a water content of 25 to 85% by weight. 4. The aqueous ballpoint pen according to any one of items 1 to 3, wherein the carboxyl group-containing crosslinkable hydrophilic polymer is a polymer of a carboxyl group-containing monoethylenic monomer and a crosslinking monomer. 5. The carboxyl group-containing crosslinkable hydrophilic polymer is a carboxyl group-containing monomer, a polymer of a monoethylenic monomer copolymerizable with the monomer and a crosslinking monomer,
The water-based ballpoint pen according to any one of items 1 to 3. 6. Polymer in which a carboxyl group-containing crosslinkable hydrophilic polymer is crosslinked with one or more crosslinking monomers selected from polyalkylene glycol bisallyl ethers having at least two unsaturated groups, allyl sucrose, and polyfunctional acrylic monomers The water-based ballpoint pen according to any one of items 1 to 5. 7. 7. The water-based ballpoint pen according to any one of items 1 to 6, wherein an anticorrosive lubricant is added to the ink. 8. Item 8. The water-based ballpoint pen according to any one of Items 1 to 7, wherein a pH adjusting agent is added to the ink. 9. The water-based ballpoint pen according to any one of items 1 to 8, wherein an antibacterial agent is added to the ink. 10. Item 10. The water-based ballpoint pen according to any one of Items 1 to 9, wherein a backflow prevention liquid plug is inserted into a side of the ink cylinder opposite to the side on which the ballpoint pen tip is mounted. Regarding

[0006]

The function of the present invention is to swell and to have a particle size of 0.5 to 10.0 μm.
Of at least two polymerizable unsaturated groups, which are 0.5 mol% or more based on the total amount of the copolymerizable monoethylenic monomer optionally used in combination with the carboxyl group-containing monomer as gel particles. The first characteristic is that a carboxyl group-containing crosslinkable hydrophilic polymer crosslinked with the crosslinking monomer is used.

The crosslinkable hydrophilic polymer is a polymer in which a crosslinkable monomer portion obtained by copolymerizing a monomer having a carboxyl group is crosslinked with each other to form a three-dimensional network structure. Examples of the monomer that forms the cross-linkable hydrophilic polymer include carboxyl group-containing monomers such as acrylic acid, meatacrylic acid, itaconic acid, maleic anhydride, and fumaric acid, and one or more of these are used. Further, acrylamide or vinylpyrrolidone can be used in combination as the hydrophilic monomer.

The cross-linking monomers are polyalkylene glycol bis allyl ethers such as diethylene glycol bis allyl ether which is an alkenyl ether having at least two unsaturated groups, allyl sucrose, and polyfunctional acrylics such as trimethylol propane triacrylate. It is a system monomer. Among these, when a carboxyl group-containing monomer or other copolymerizable monomer is used in combination, the one using 0.5 mol% or more of the crosslinking monomer has a good three-dimensional network structure and swells in the ink. Then, a crosslinked hydrophilic polymer dispersed in a gel form is suitably formed. When the amount of the crosslinking monomer is less than 0.5 mol%, the three-dimensional network structure is weak, so that the swollen gel dispersed particles are not formed and the ink is dissolved in the ink, and the ink drips from the ballpoint pen tip.

Examples of the compounding of the carboxyl group-containing monomer and the crosslinking monomer are as follows: (1) 11.8 parts by weight of acrylic acid monomer (0.164)
Mol part) and 0.3 part by weight of diethylene glycol bisallyl ether (0.0016 mol part) as a crosslinking monomer, and in this case, the crosslinking monomer is 1.0 mol%. (2) 100 parts by weight of methacrylic acid monomer (1.16
Mol part) and 2.5 parts by weight of diethylene glycol bismethacryl ether (0.012 mol part), and in this case also the crosslinking monomer is about 1.0 mol%. (3) 10 parts by weight (0.139 parts by mole) of acrylic acid monomer, 2 parts by weight (0.020 parts by mole) of maleic anhydride and 0.6 of polyethylene glycol bismethacryl ether.
Parts by weight (0.00185 mol), in this case about 1.2 mol% of the crosslinking monomer. The copolymer of the carboxyl group-containing monomer and the crosslinking monomer is generally obtained as a white fine powder by conducting the polymerization in a solution in which the copolymer does not dissolve. These powders swell in the ink to form a crosslinked hydrophilic polymer dispersed in a gel form. The crosslinked hydrophilic polymer used in the present invention which is swollen in the ink and dispersed in a gel form improves the stability of the ink over time, and has an excellent effect of making the ink a suitable plastic liquid.

Examples of the aqueous medium used in the present invention include water or a mixture of water and a moisturizing agent. The moisturizer is added to prevent evaporation of water in the ink, and is ethylene glycol, propylene glycol, glycerin, diethylene glycol, triethylene glycol, dipropylene glycol, thiodiglycol, polyglycerin, polyethylene glycol, polypropylene glycol, methyl glycol. Water-miscible ones such as cellosolve, butyl cellosolve, methyl carbitol, ethyl carbitol and the like can be mentioned. These moisturizers may be used alone or in combination of two or more kinds. The amount of the aqueous medium is 5 to 90% by weight of water, and the moisturizer is 0 to 50% by weight.
However, water is preferably 25 to 90% by weight and a moisturizing agent is 0 to 5
0% by weight, more preferably 30 to 85% by weight of water and 0 to 50% by weight of humectant. In the present invention, a pigment is used as a colorant. Pigments have higher handwriting contrast than dyes, are superior in water resistance and light resistance, and maintain sharpness for a long time. The pigment to be used is not particularly limited, and examples thereof include organic pigments, inorganic pigments, and fluorescent pigments, and these may be used alone or in combination of two or more kinds. The amount of pigment is 1 to 50% by weight
Is preferred. The blending amount of pigment is 1 for inorganic pigments and organic pigments.
-50% by weight, especially 1-30% by weight is preferred, and the fluorescent pigment is 1-50% by weight, preferably 5-50% by weight. The carboxyl group-containing polymer is preferably used in an amount of 0.1 to 2.0% by weight. When the number of swollen gel dispersed particles in the ink is small, the interaction between the swollen gel dispersed particles and the pigment is insufficient, and the effect of preventing the ink from dripping from the ballpoint pen tip becomes insufficient. On the other hand, if the number of swollen gel dispersed particles in the ink is too large, the interaction between the particles that acts between the swollen gel dispersed particles and the pigment is too strong. The interaction cannot be sufficiently disrupted, which hinders smooth ink outflow. Therefore, the blending amount of the crosslinkable hydrophilic polymer forming the swollen gel dispersed particles in the ink in the present invention is 0.1 to 10.
2.0% by weight is preferred.

The pigment has an advantage that an ink can be easily prepared by using an aqueous pigment dispersion. Anti-rust lubricant is
Phosphate ester type surfactant, benzotriazole, fatty acid ester and the like are used. The ball-point pen tip of the water-based ball-point pen is composed of a metal ball and a ball receiver, but since the ink is water-based, the ball tends to rust and the rotation of the ball tends to deteriorate. The addition of a rust preventive lubricant not only prevents the occurrence of rust, but also has the effect of smoothing the rotation of the ball. The amount of the rust preventive lubricant compounded is preferably 0.2 to 2.0% by weight.

In addition, pH adjusting agents such as monoethanolamine, diethanolamine, triethanolamine, N, N-dimethylethanolamine, N, N-diethylethanolamine, N, N-dibutylethanolamine and N-methyldiethanolamine are used. It can be added in an amount of 0.1 to 6.0% by weight. In order for the crosslinked acrylic acid-based resin to swell in the ink and disperse in a gel state, swelling is promoted by neutralizing the carboxyl group. Therefore, it is effective to add a pH adjuster, and various amines are added as pH adjusters in Examples. The pH adjusting agent is not necessarily required for the crosslinked acrylic acid resin in a salt state in which the carboxyl group is previously neutralized with sodium or the like.

If necessary, an antibacterial agent such as 1,2-benzisothiazolin-3-one, sodium benzoate and sodium dehydroacetate may be added to the composition to improve storage stability.

The second feature of the present invention is that the clearance between the ball and the ball receiver constituting the ball-point pen tip is 10.0 to 40.0 μm, and the ball-point pen tip and the above ink are combined. From the experimental results, when the particle diameter of the swollen gel dispersed particles is less than 0.5 μm, the ink is almost dissolved and the ink dripping cannot be prevented.
If it exceeds 0.0 μm, it becomes difficult for the ink to flow through the ink flow path, and the ink discharge deteriorates. When the clearance of the ball-point pen tip is less than 10.0 μm, the ink dripping can be prevented, but the ink discharge deteriorates. If it exceeds 40.0 μm, ink dripping occurs, and especially in an atmosphere in which the relative humidity exceeds 90%, the ink dripping becomes remarkable. Therefore, the particle diameter of the swollen gel dispersed particles in the ink is 0.5 to
Within the range of 10.0 μm, the clearance between the ball and the ball receiver constituting the ball-point pen tip is 10.0.
It is necessary to be within the range of ˜40.0 μm. Even if either one of the conditions is not satisfied, the ink drips or the ejection of the ink is deteriorated, so that a ballpoint pen having good writing properties cannot be obtained.

Regarding the theoretical basis of such effects,
Although not always clearly explained, the present inventor, when the particle size of the swollen gel dispersed particles and the clearance of the ball-point pen tip are in an appropriate range, the swollen gel dispersed particles and the pigment interact due to the interaction between the particles when the aqueous ballpoint pen is stationary. The clearance of the ballpoint pen tip is closed to prevent ink from dripping from the ballpoint tip. It is considered that the interaction is broken at the time of writing when the shearing force is applied to the ink, that is, when the ball is rotated, so that the ink smoothly flows out from the clearance of the ballpoint pen tip.

In the present invention, an ink is prepared by mixing and dispersing an aqueous medium, a pigment, a crosslinkable hydrophilic polymer, and if necessary, a pH adjusting agent, a surfactant and a bacteriostatic agent, and the particles of the swollen gel dispersed particles are used. The diameter is adjusted by shearing and stirring during dispersion. Dispersion can be performed using various types of stirrers and dispersers. However, 1000 r. p. With low shear stirring of m or less (homodisperser), a swollen gel outside the above particle size range is obtained, and 3
000r. p. A swelling gel within the above particle size range can be realized by stirring for m or more. The particle size can be confirmed by an ordinary optical microscope.

As for the clearance between the ball and the ball receiver, as shown in FIG. 1, with the tip of the ballpoint pen tip 1 in contact with the digital indicator 2, the needle 3 is inserted from the rear of the ballpoint pen tip 1 and the needle 3 Is measured by pushing the ball 4 and moving the shaft 5 of the digital indicator 2. In the figure, 6 is a jig, 7 is a needle guide,
Reference numeral 8 denotes a guide of the digital indicator shaft.

The ball-point pen tip is not only an ordinary cone type consisting of a metal ball receiver that holds a ball, but the tip of a metal pipe is processed to form a ball seat, and the ball is held on the ball seat. There is a pipe type ball-point pen tip, and the ball is approximately 0.3 to 1.6 m depending on the thickness of the handwriting.
A diameter of m is used.

[0019]

EXAMPLES Next, the present invention will be specifically described by showing examples.

[0020] (1) Preparation of formulation liquid Formulation liquid A   Glycerin (moisturizer) 30.0 parts by weight   Triethanolamine (pH adjuster) 1.8 parts by weight   Polyoxyethylene alkyl ether phosphate ester 1.0 part by weight                           (Surfactant)   1,2-benzisothiazolin-3-one 0.2 parts by weight             10% propylene glycol aqueous solution (antibacterial agent)   Ion-exchanged water 15.0 parts by weight Was blended to prepare a blended liquid A.

[0021] Formulation B   Glycerin (moisturizer) 20.0 parts by weight   Triethanolamine (pH adjuster) 0.8 parts by weight   Polyoxyethylene alkyl ether phosphate ester 1.0 part by weight                           (Surfactant)   1,2-benzisothiazolin-3-one 0.2 parts by weight             10% propylene glycol aqueous solution (antibacterial agent)   Deionized water 25.0 parts by weight Was blended to prepare a blended liquid B.

[0022] Formulation C   Ethylene glycol (moisturizer) 30.0 parts by weight   Triethanolamine (pH adjuster) 0.8 parts by weight   Polyoxyethylene alkyl ether phosphate ester 1.5 parts by weight                           (Surfactant)   1,2-benzisothiazolin-3-one 0.2 parts by weight             10% propylene glycol aqueous solution (antibacterial agent)   Ion-exchanged water 17.1 parts by weight Was blended to prepare a blended liquid C.

[0023] Formulation D   Ethylene glycol (moisturizer) 10.0 parts by weight   Glycerin (moisturizer) 10.0 parts by weight   Triethanolamine (pH adjuster) 0.8 parts by weight   Polyoxyethylene alkyl ether phosphate ester 1.5 parts by weight                           (Surfactant)   1,2-benzisothiazolin-3-one 0.2 parts by weight             10% propylene glycol aqueous solution (antibacterial agent)   Deionized water 27.1 parts by weight Was blended to prepare a blended liquid D.

[0024] Formulation E   Glycerin (moisturizer) 20.0 parts by weight   N, N diethylamine ethanolamine (pH adjuster) 0.8 parts by weight   Polyoxyethylene alkyl ether phosphate ester 1.5 parts by weight                           (Surfactant)   1,2-benzisothiazolin-3-one 0.2 parts by weight             10% propylene glycol aqueous solution (antibacterial agent)   Deionized water 27.1 parts by weight Was blended to prepare a blended liquid E.

(2) Ink formulation example Formulation example 1 47.0 parts by weight of formulation liquid B was mixed with Titikaka Color Red F.
-14 (manufactured by Mikuni dye company, aqueous pigment dispersion, solid content 16)
%) 50.0 parts by weight, 2.6 parts by weight of ion-exchanged water, and 0.4 parts by weight of a cross-linking acrylic acid-based resin cross-linked with 1.2 mol% of a crosslinking monomer with respect to a carboxyl group-containing monomer, 50-60 ° C, Homo Disperser 3000
r. p. After stirring and dispersing for 20 minutes at m, a red ink was obtained. The cross-linked acrylic acid resin in the ink forms a swollen gel dispersion, and the particle size of the dispersion is 1 to 1
It was in the range of 2 μm.

Blending Example 2 48.0 parts by weight of blended solution B was added to Victoria Color Pink.
G-23 (manufactured by Mikuni dye company, aqueous pigment dispersion, solid content 4)
0%) 50.0 parts by weight, ion-exchanged water 1.6 parts by weight, and 0.4% of a cross-linking acrylic acid resin cross-linked with 0.8 mol% of a crosslinking monomer with respect to a carboxyl group-containing monomer.
By adding parts by weight, a fluorescent pink ink was prepared in the same manner as in Formulation Example 1. The cross-linked acrylic acid-based resin in the ink formed a swollen gel dispersion, and its particle size was examined under a microscope to find that it was within the range of 1 to 2 μm.

Blending Example 3 47.0 parts by weight of blended solution B was mixed with Titicaca Color BLAC.
50.0 parts by weight of KF-10 (manufactured by Mikuni dye company, aqueous pigment dispersion, solid content 19%), 2.6 parts by weight of deionized water,
Cross-linking acrylic resin 0.4 cross-linked with 0.8 mol% of the crosslinking monomer based on the carboxyl group-containing monomer
After adding parts by weight and stirring to sufficiently wet the cross-linked acrylic acid-based resin, Dynomill (diameter of zircon beads is 0.5 to
0.8 mm) and dispersed for 50 minutes to obtain a black ink. The cross-linked acrylic acid-based resin in the ink formed a swollen gel dispersion, and the particle size of the dispersion was found to be 0.
It was in the range of 5 to 1 μm.

Formulation Example 4 48.0 parts by weight of Formulation Solution A was mixed with Victoria Color Yell.
ow G-20 (manufactured by Mikuni dye company, aqueous pigment dispersion, solid content 40%) 50.0 parts by weight, ion-exchanged water 1.7 parts by weight, 0.4 mol% of a crosslinking monomer with respect to a carboxyl group-containing monomer 0.3 parts by weight of the cross-linking acrylic acid resin cross-linked by (4) was added, and a fluorescent yellow ink was obtained in the same manner as in Formulation Example 1. When examined under a microscope, the crosslinked acrylic acid-based resin in the ink was found to be dissolved.

Formulation Example 5 Victoria Color Green was added to 48.0 parts by weight of Formulation A.
n G-24C (manufactured by Mikuni dye company, aqueous pigment dispersion, solid content 40%) 50.0 parts by weight, ion-exchanged water 0.6 parts by weight, solid content 30% by weight not crosslinked with a crosslinking monomer 1.4 parts by weight of the acrylic ester copolymer aqueous emulsion was added and stirred for 5 minutes to obtain a fluorescent green ink. When examined under a microscope, the acrylic acid ester copolymer in the ink was dissolved.

Formulation Example 6 49.6 parts by weight of Formulation Solution C is added to Chichikara Color BLACK.
5-10 parts by weight of F-10 (described above) and 0.4 parts by weight of a cross-linking acrylic acid-based resin cross-linked with 0.8 mol% of a cross-linking monomer with respect to a carboxyl group-containing monomer were added, and a formulation example 1 was obtained. Black ink was obtained by the same method. The cross-linked acrylic acid-based resin in the ink formed a swollen gel dispersion, and its particle size was examined under a microscope to find that it was within the range of 1 to 2 μm.

Blending Example 7 49.6 parts by weight of the blended liquid D was mixed with Chichikara Color Red F.
-14 (manufactured by Mikuni dye company, aqueous pigment dispersion, solid content 16)
%) 50.0 parts by weight, 0.4 parts by weight of a crosslinkable acrylic resin crosslinked with 1.2 mol% of a crosslinking monomer with respect to a carboxyl group-containing monomer is added, and a red color is obtained in the same manner as in the formulation example 1. And the ink. The cross-linked acrylic acid-based resin in the ink formed a swollen gel dispersion, and its particle size was examined under a microscope to find that it was within the range of 1 to 2 μm.

Formulation Example 8 49.6 parts by weight of Formulation Solution E was added to Chichikara Color Blue.
F-21 (manufactured by Mikuni dye company, aqueous pigment dispersion, solid content 25)
%) 50.0 parts by weight, 0.4 parts by weight of a cross-linking type acrylic acid resin cross-linked with 0.8 mol% of a cross-linking monomer to a carboxyl group-containing monomer is added, and a blue color is obtained in the same manner as in Formulation Example 1. And the ink. The cross-linked acrylic acid-based resin in the ink formed a swollen gel dispersion, and its particle size was examined under a microscope to find that it was within the range of 1 to 2 μm.

(3) Example of ball-point pen tip A normal cone-type ball-point pen tip in which a ball made of a super-hard alloy is held is made in a ball seat of a stainless steel ball receiver, and the ball and the ball receiver are separated by the above-described measuring method. The clearance (corresponding to the movable amount of the ball moving in the front-back direction of the ballpoint pen tip) was measured. Based on the measured values, the groups were divided as follows. Group A: Ball diameter is 0.7 mm and clearance is 7
Within the range of ~ 8 μm Group B1 ... Ball diameter is 0.5 mm and clearance is 1
Within the range of 5 to 25 μm, the group B2 has a ball diameter of 0.7 mm and a clearance of 1
Within the range of 5 to 25 μm, Group C ... Ball diameter is 0.5 mm and clearance is 2
Within the range of 5 to 35 μm Group D: Ball diameter is 0.5 mm and clearance is 4
Those exceeding 0 μm Next, examples of making ballpoint pens by the above-mentioned formulation examples and ballpoint pen tip examples will be shown.

Example 1 Five ballpoint pen tips selected from Group B1 of the ballpoint pen tip example were mounted in ink cylinders each having an inner diameter of 4 mm, and 1.2 g of the ink of formulation example 1 was directly filled in each ink cylinder, and A backflow prevention liquid plug mainly composed of grease was inserted in the rear part to form five aqueous ballpoint pens.

Examples 2 to 6 Formulation examples 2, 3 and 6 were carried out in the same manner as in Example 1 by using ballpoint pen tips selected from the B1 group, B2 group and C group of the ballpoint pen tip examples (five in each example). The water-based ballpoint pens filled with the inks of Nos. 8 to 8 are shown in Table 1 as Examples 2 to 6, respectively.

Comparative Examples 1 to 11 Using the ballpoint pen tips selected from the group A, the group B1 and the group D of the example ballpoint tips (five in each example), the inks of formulation examples 1 to 8 were prepared in the same manner as in Example 1. The water-based ballpoint pens filled with are shown in Table 1 as Comparative Examples 1 to 11, respectively.
With respect to the water-based ballpoint pen prepared as described above, the writability and the ink dripping prevention performance were evaluated. The writability was determined by visually observing by writing on a normal paper, dividing the state where there was no line blurring into the circle, and dividing the state into the cross. Ink dripping prevention performance is as follows: each water-based ballpoint pen is placed in an atmosphere of 20 ° C and relative humidity of 90% with the ballpoint pen tip facing downward, and the ink leakage from the tip of the ballpoint pen tip after standing vertically for 2 hours is checked. Was judged as ○, and in some cases as ×. The results are also shown in Table 1.

[0037]

[Table 1]

As is clear from the above table, the swelling gel-dispersed particles of the crosslinkable hydrophilic polymer used in the present invention are used, and the particle size is 0.5 to 10.0 μm.
In a ball-point pen having a clearance between the ball and the ball receiver constituting the ball-point pen tip of 10.0 to 40.0 μm, the ink does not drip and the writability is good.

[0039]

INDUSTRIAL APPLICABILITY The water-based ballpoint pen of the present invention has good ink ejection, no line blurring or line marking, high handwriting contrast, is clear for a long time, and is excellent in ink sag prevention performance.

[Brief description of drawings]

FIG. 1 is an explanatory diagram illustrating a method of measuring a clearance of a ballpoint pen tip.

[Explanation of symbols]

1 ballpoint pen tip 2 Digital indicator 3 needles Four balls 5 Digital indicator shaft 6 jigs 7 needle guide 8 Digital indicator shaft guide

Front page continued (72) Inventor Shinichi Muragata 1-3-4 Nishihachiman, Hiratsuka-shi, Kanagawa Pilot Hiratsuka factory (72) Inventor Hozo Murata 1-3-4 Nishihachiman, Hiratsuka-shi, Kanagawa (56) References JP 57-49678 (JP, A) JP 6-57194 (JP, A) JP 6-328891 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) B43K ^7/ 00-7/12 B43K 1/08 C09D 11/18

Claims (10)

(57) [Claims] 1. (A) a. An aqueous medium, b. A pigment and c. 0.5 mol% with respect to the total amount of the copolymerizable monoethylenic monomer which is swollen to form particles having a particle size of 0.5 to 10.0 μm and dispersed in a gel state, which is optionally used in combination with the carboxyl group-containing monomer. A water-based ink comprising the above-mentioned carboxyl group-containing cross-linking hydrophilic polymer cross-linked with at least two cross-linking monomers having a polymerizable unsaturated group (B) has a clearance between the ball and the ball receiver of 1
A water-based ballpoint pen directly packed in an ink cylinder equipped with a ballpoint pen tip in the range of 0.0 to 40.0 μm. 2. An ink comprising 5 to 90% by weight of water, 0 to 50% by weight of a moisturizing agent, 1 to 50% by weight of a pigment, and 0.1 to 2.0% by weight of a crosslinkable hydrophilic polymer containing a carboxyl group is used. The water-based ballpoint pen according to claim 1. 3. The water-based ballpoint pen according to claim 1, wherein an ink having a water content of 25 to 85% by weight is used. 4. The water-based ballpoint pen according to claim 1, wherein the carboxyl group-containing crosslinkable hydrophilic polymer is a polymer of a carboxyl group-containing monoethylenic monomer and a crosslinking monomer. 5. The crosslinkable hydrophilic polymer containing a carboxyl group is a polymer containing a carboxyl group-containing monomer, a monoethylenic monomer copolymerizable with the monomer, and a crosslinking monomer, according to any one of claims 1 to 3. The water-based ballpoint pen described in 1. 6. One or more cross-linking monomers selected from polyalkylene glycol bisallyl ethers in which the carboxyl group-containing cross-linkable hydrophilic polymer has at least two unsaturated groups, allyl sucrose, and polyfunctional acrylic monomers. The water-based ballpoint pen according to any one of claims 1 to 5, which is a polymer cross-linked with. 7. The water-based ballpoint pen according to claim 1, wherein an anticorrosive lubricant is added to the ink. 8. The water-based ballpoint pen according to claim 1, wherein a pH adjusting agent is added to the ink. 9. The water-based ballpoint pen according to claim 1, wherein a fungicide is added to the ink. 10. The water-based ballpoint pen according to claim 1, wherein a backflow preventing liquid stopper is inserted on the side of the ink cylinder opposite to the side on which the ballpoint pen tip is mounted.