JP6734128B2 - Water-based ballpoint pen - Google Patents

Description

TECHNICAL FIELD The present invention relates to a water-based ballpoint pen, and more particularly, to a water-based ballpoint pen that suppresses ink leakage and is excellent in writing quality and has a strong handwriting.

As an ink composition for a ballpoint pen used for a conventional ballpoint pen, as in Patent Document 1, Japanese Patent No. 3338222 “Direct liquid knock type water-based ballpoint ink”, the moisturizing property is improved and even if the pen is left without a cap, Ink for direct liquid knock type water-based ballpoint pens that does not cause direct current phenomenon such as ink squirting out or hanging down from the tip of a pen, and JP-B-6-47661 “Ball Pen Ink Composition” as Patent Document 2. Discloses a ball-point pen ink having an ink viscosity of 50 to 2000 cps.

"Patent No. 3338222" "Japanese Patent Publication No. 6-47661"

However, when using these water-based inks for ball-point pens to make retractable ball-point pens or cap-off state ball-point pens, when the ball-point pens are in the downward state, ink dripping may occur due to ink leakage from the tip of the tip. It was

By the way, with respect to the ballpoint pen displayed in the display case, the user takes the ballpoint pen out of the display case, returns the ballpoint pen to the display case by performing trial writing, confirming a knock operation, and the like.

At this time, in the case of a cap-off type ballpoint pen such as a retractable ballpoint pen, when the ballpoint pen tip is returned to the display case, the ball of the ballpoint pen tip contacts the bottom of the ballpoint pen display case. .. In this way, while repeatedly returning the ballpoint pens on which trial writing has been performed to the same display case, many ballpoint pens were stacked on top of the ballpoint pen that was returned first, and as a result Due to the weight, the ball receives the impact when the tip of the ball-point pen tip comes into contact with the bottom of the ball-point 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. Then, the ink drips from the gap, ink is leaked, and the display case is soiled, and the ballpoint pens in the other cases are also soiled, and there is room for improvement.

In order to solve the above-mentioned ink leakage, if the ink viscosity is increased as a method for dealing with ink, the ink consumption is reduced, dark handwriting cannot be obtained, and the writing quality when writing is poor. In addition, as a method for dealing with chips, ink is drooped by constantly pressing a ball against the inner wall surface of the tip of the chip with a coil spring or the like inside the chip body to close a minute gap between the ball and the tip of the chip. Although it is possible, there was room for improvement because the manufacturing cost increased, the rotation of the ball was inferior, and the writing quality was easily affected.

An object of the present invention is to provide a water-based ballpoint pen that suppresses ink leakage, has excellent writing quality, and produces thick handwriting.

The present invention, in order to solve the above problems,
1. A water-based ball-point pen having a ball-point pen tip at the tip of an ink container and containing an ink composition for a water-based ball-point pen in the ink container, wherein the ball-point pen tip extends in the direction of the longitudinal axis of the ball. A water-based ball-point pen, wherein the transfer amount is 15 to 50 μm, and the water-based ball-point pen ink composition contains water, a colorant, organic resin particles, and a polysaccharide fiber.
2. Content of the said polysaccharide fiber is 0.01-5.0 mass% with respect to the ink composition whole quantity, The water-based ball-point pen of Claim 1 characterized by the above-mentioned.
3. 3. The water-based ballpoint pen according to item 1 or 2, wherein the organic resin particles are olefin resin particles or nitrogen-containing resin particles.
4. 4. The water-based ballpoint pen according to any one of items 1 to 3, wherein the water-based ballpoint pen ink composition contains a phosphoric acid ester-based surfactant or a fatty acid.
5. A retractable type in which the water-based ballpoint pen according to any one of claims 1 to 4 is slidably arranged in a barrel, and the tip end portion of the ballpoint pen tip is retractable from the barrel end portion. A water-based ball-point pen characterized by being a water-based ball-point pen. ".

The present invention returns the ballpoint pen to the display case in a state where the ballpoint pen tip is projected, and even if a gap occurs between the ball and the inner wall of the tip of the tip, the ink leakage is suppressed and the writing quality is excellent and the handwriting is dark. It was possible to provide a water-based ballpoint pen.

A feature of the present invention is a water-based ball-point pen having a ball-point pen tip at the tip of an ink containing cylinder and containing an ink composition for a water-based ball-point pen in the ink containing cylinder, wherein a vertical axis of a ball of the ball-point pen tip. The amount of movement in the direction is 15 to 50 μm, and the ink composition for a water-based ball-point pen includes water, a colorant, organic resin particles, and a polysaccharide fiber, which is an aqueous ball-point pen.

In the present invention, the amount of movement of the ball of the ball-point pen tip in the longitudinal direction of the ball must be set to 15 to 50 μm in order to suppress ink leakage and produce a thick handwriting. This is because when the thickness is 15 μm or more, the ink discharge amount is increased and a dark handwriting can be obtained, and when the thickness is further 50 μm or less, there is no handwriting bleeding or bloating, and good writing performance is obtained. Further, in order to increase the ink discharge amount to improve the writing quality and make it easier to obtain thick handwriting, the thickness is preferably 20 μm or more, and therefore 20 to 50 μm is preferable, and further considering the ink leakage suppression, 25 to 45 μm is preferable.
The movement amount (clearance) of the ball of the ball-point pen tip in the vertical axis direction indicates the distance that the ball can move in the vertical axis direction of the ball-point pen tip body.

However, simply increasing the ink discharge amount causes the problem of ink leakage (ink dripping) from the gap between the ball and the inner wall of the tip of the chip. By increasing the ink viscosity, ink leakage could be suppressed to some extent, but it was not at a sufficient level and the writing quality was also likely to be poor.

Therefore, in the present invention, by containing organic resin particles, a physical obstacle is caused in the gap between the ball and the inner wall of the tip of the chip, and it is possible to suppress ink leakage. Since the hardness is lower than that of, the particles are partially deformed and adhere to each other, resulting in a structure formed by weak agglomeration, resulting in resistance to ink leakage during standing. By forming a highly effective structure in the ink, it is possible to suppress high ink leakage. On the other hand, because the structure is formed by weak agglomeration, the agglomerated structure is crushed by physical action such as rotation of the ball during writing, so write well without hindering the ink fluidity during writing. With that, it is possible to obtain deep handwriting. Further, since the organic resin particles enter between the ball and the ball seat and make it difficult to make direct contact with each other, it is possible to reduce the rotational resistance of the ball and improve the writing quality.

Furthermore, in addition to the organic resin particles, by containing a polysaccharide fiber, the viscosity of the ink is increased, the leakage of the ink is further suppressed, and the writing quality is improved in order to further improve the writing quality. It is necessary that This is because by including the polysaccharide fiber, by interposing the polysaccharide fiber between the organic resin particles, by intertwining with the aggregation structure formed between the organic resin particles, three-dimensional It is assumed that it forms a structure and exhibits a high ink leakage suppression effect.
From the above, the amount of movement of the ball of the ballpoint pen tip in the vertical axis direction is 15 to 50 μm, and the aqueous ink composition for a ballpoint pen contains water, a colorant, organic resin particles, and a polysaccharide fiber. By using the water-based ball-point pen, it is possible to suppress ink leakage and to obtain a water-based ball-point pen that is excellent in writing performance and writing quality and has thick handwriting.

(Organic resin particles)
The organic resin particles used in the present invention include olefin resin particles such as polyethylene resin and polypropylene resin, and chemical structures of melamine/formaldehyde resin, benzoguanamine/formaldehyde resin, benzoguanamine/melamine/formaldehyde resin, urea formaldehyde resin, nylon resin, etc. Examples thereof include nitrogen-containing resin particles containing nitrogen atoms, acrylic resin particles, styrene resin particles, epoxy resin particles, urethane resin particles, and cellulose resin particles. These organic resin particles may be used alone or in combination of two or more kinds.

Among the organic resin particles, it is preferable to use olefin resin particles and nitrogen-containing resin particles. This is because the olefin resin particles are a hydrocarbon compound and are likely to aggregate in water because they are non-polar, and the aggregate structure and the polysaccharide fiber are entangled with each other to easily form a three-dimensional structure. It is presumed that this is because it is easy to form an optimized agglomerated structure that does not cause problems such as insufficient ink discharge while suppressing ink leakage. Furthermore, since the olefin resin particles have a high melting temperature, they are likely to exist stably even in a high temperature environment, and when they are in a high pressure environment, they are easily deformed and are not easily modified. 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.
Further, the nitrogen-containing resin particles, it is preferable to use nitrogen-containing resin particles having a hydrogen-bonding functional group, which is the tertiary structure by the hydrogen-bonding functional group structure and the polysaccharide fiber intertwined with each other, It is presumed that the original structure is easily formed and the ink leakage suppression effect is more exhibited.

Examples of the material of the olefin resin particles include polyolefins such as polyethylene, polypropylene and polybutene, and a mixture thereof. Among these, polyethylene is preferably used from the viewpoints of suppressing ink leakage and improving writing quality, and specifically, low density polyethylene, high density polyethylene, low molecular weight polyethylene, modified polyethylene, modified high density polyethylene. And so on. Of these, low density polyethylene, low molecular weight polyethylene, and modified polyethylene are preferable in view of the effect of suppressing ink leakage. Especially, since low density polyethylene has a lower melting point and softer properties than other types of polyethylene, polyethylene particles adhere closely. Low density polyethylene is preferable because it is easy to create gaps between particles and ink does not easily leak.Because low density polyethylene is soft, it is easy to obtain a cushioning effect between the ball and the ball seat, making it easier to write. And the wear of the ball seat can be suppressed, so that it can be preferably used. The olefin-based resin particles may contain a material other than polyolefin, if necessary.

Further, the olefin resin particles are preferably an olefin dispersion previously dispersed in water or the like, but the pH value of the olefin dispersion is preferably 7 to 11. This is because it is easy to improve the dispersion stability of the olefin resin particles and the stability with respect to ink components such as colorants and surfactants. From a further consideration, a pH value of 7 to 10 is more preferable.

Among the nitrogen-containing resin particles, it is preferable to have an amino group or an imino group, because when it has an amino group or an imino group, it is easy to take a stable aggregation structure for a long period of time, and it is easy to suppress ink leakage. is there. The nitrogen-containing resin particles having a functional group such as an amino group and an imino group include tertiary amine and quaternary amine.

Further, among the nitrogen resin particles having an amino group or an imino group, it is preferable to use nitrogen-containing resin particles having a crosslinked structure. The crosslinked structure is preferable because it is particularly excellent in strength, heat resistance, solvent resistance, and the like, and is stable without absorbing moisture in the water-based ink, and thus excellent in stability over time. Further, the stability of the nitrogen-containing resin particles themselves and the mutual hydrogen-bonding property between the nitrogen-containing resin particles make it easy to form an agglomerated structure for a long period of time and to easily suppress ink leakage stably. In particular, among the nitrogen-containing resin particles having a crosslinked structure, resin particles having a heterocyclic structure such as melamine/formaldehyde resin, benzoguanamine/formaldehyde resin, benzoguanamine/melamine/formaldehyde resin are more difficult to absorb moisture and are stable, preferable.

Specific examples of the nitrogen-containing resin particles having a crosslinked structure include amino resin particles such as melamine/formaldehyde resin, benzoguanamine/formaldehyde resin, benzoguanamine/melamine/formaldehyde resin and urea formaldehyde resin. Examples of nitrogen-containing resin particles having an amide bond include nylon resins such as nylon 6 and nylon 12, polycarbonate polyurethane resin, polyether polyurethane resin, polyester polyurethane resin, urethane urea resin particles such as urethane urea resin. To be

The average particle size of the organic resin particles is preferably 10 μm or less, and more preferably 8 μm or less, because the smaller the average particle size, the more easily they adhere to each other and easily form a weak agglomerate structure and easily suppress ink leakage. The thickness is preferably 7 μm or less in consideration of alleviating the rotation resistance of the ball, improving the writing quality, and suppressing the wear of the ball seat. Further, since the aggregate structure is formed by the organic resin particles, it is easy to form a macroscopic aggregate structure even if the particles themselves are relatively small. Therefore, even if a finer particle size is used, an excellent ink leakage suppression effect can be obtained. You can On the other hand, if the average particle size is too small, the effect of suppressing ink leakage tends to be poor, so the average particle size is preferably 0.1 μm or more, more preferably 3 μm or more. In addition, the average particle size is a particle size measured by a laser diffraction method using a laser diffraction type particle size distribution analyzer (trade name "Microtrac HRA9320-X100", Nikkiso Co., Ltd.) or a Coulter counter method (manufactured by Coulter). It is possible to measure the particle diameter (D50) when the volume cumulative distribution is 50%.

Regarding the shape of the organic resin particles, a spherical shape or an irregular shape can be used, but spherical resin particles are preferable in view of reducing frictional resistance. The spherical resin particles here are not limited to true spherical shapes, and may be substantially spherical resin particles, substantially elliptic spherical resin particles, or the like.

Regarding the organic resin particles, specifically, Nopco PEN-17 (polyolefin resin, average particle diameter 0.01 μm), Nopcomal MS40 (polyethylene resin, average particle diameter 1.0 μm) (all manufactured by San Nopco Ltd.) ), CERAFLOUR 950 (modified polyethylene resin, average particle diameter 9 μm), 925 (modified polyethylene resin, average particle diameter 6 μm), 929 (modified polyethylene resin, average particle diameter 8 μm) (manufactured by BYK), Chemipal M200 ( Low density polyethylene dispersion, average particle diameter 6 μm, W300 (low molecular weight polyethylene dispersion, average particle diameter 3 μm), W900 (low molecular weight polyethylene dispersion, average particle diameter 0.6 μm) (above Mitsui Chemicals, Inc.) Manufactured), Eposter S6 (melamine-formaldehyde condensed particles, average particle size 0.3 to 0.6 μm), S (melamine formaldehyde condensed particles, average particle size 0.1 to 0.3 μm), S12 (melamine Formaldehyde condensed particles, average particle size 1-2 μm, MS (benzoguanamine/formaldehyde condensed particles, average particle size 1-3 μm), M30 (benzoguanamine/melamine/formaldehyde condensed particles, average particle size 2.5-4 μm) ( Above, manufactured by Nippon Shokubai Co., Ltd., nylon SP-500 (nylon resin, average particle size 5 μm) (manufactured by Toray Co., Ltd.), 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) (all manufactured by Arkema Ltd.), MW-330 (nylon resin, average particle size) Diameter 7 μm (manufactured by Sumika Environmental Science 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) (above Nippon Paint Co., Ltd. ) Made) etc. are mentioned.

Further, the content of the organic resin particles is more preferably 0.01 to 10.0 mass% with respect to the total amount of the ink composition. This is because if the content of the organic resin particles is less than 0.01% by mass, it is difficult to suppress ink leakage, and if it exceeds 10.0% by mass, the agglomerated structure tends to be strong, and the writing feel and dry-up performance are improved. This is because it is likely to be affected. Furthermore, if further considered, 0.02 to 5.0 mass% is preferable, 0.03 to 1.0 is particularly preferable, and 0.05 to 0.5 mass% is most preferable.

(Polysaccharide fiber)
The polysaccharide fiber can be obtained by using a polysaccharide raw material containing a polysaccharide such as cellulose, chitin and chitosan. This is because the hydrogen bonding force due to the hydroxyl group of the polysaccharide fiber is weak, but by forming an aggregate structure by a weak hydrogen bond, an ink leakage suppression effect is obtained and the hydrogen bonding force is weak. This is because the agglomerated structure is easily broken by the rotation of the ball during writing. For this reason, not only the effect of suppressing ink leakage when standing still, but also the effect of simultaneously improving writing performance such as writing performance and writing quality can be obtained. Furthermore, since the polysaccharide fiber having a hydroxyl group is easier to disperse in water than other fibers, stable dispersion in an aqueous ink makes it possible to stabilize the ink aging for a long period of time, which is more effective. Is.

Specific examples of the polysaccharide fiber having a hydroxyl group include fibers such as cellulose, chitin and chitosan, and cellulose fiber is preferable. This is because the number of hydroxyl groups per molecule is large, so the effect of suppressing ink leakage due to hydrogen bonding is more likely to be obtained, stable dissolution is easier in aqueous ink, and the long-term effect is easily obtained. Is preferable because it has a small load and is excellent in reusability.

Moreover, it is preferable that the above-mentioned polysaccharide fiber is defibrated by a machine or the like. When the minor axis of the fiber is the fiber diameter, the fiber diameter is not particularly limited, but the number average fiber diameter is preferably 0.1 nm to 1000 nm, more preferably 1 nm, as observed by an electron microscope such as SEM or TEM. ˜500 nm, more preferably 2 nm to 200 nm. This is because when the number average fiber diameter is in the above range, the effect of suppressing ink leakage and improving writing quality can be easily obtained.

In addition, since hydrogen bonds such as hydroxyl groups are working between or in the molecules of the above-mentioned polysaccharide fiber, it is easy for the machine to take time for the defibration process. Therefore, the surface treatment of the polysaccharide fiber with a compound having a hydrophilic group enhances the ionic repulsion property, which facilitates the defibration treatment, which is preferable. Examples of the hydrophilic group include a compound having a phosphoric acid group, a compound having a carboxyl group, a compound having an amino group, a compound having a sulfo group, and the like, in consideration of the defibration treatment, a compound having a phosphoric acid group, It is preferable to use a compound having a carboxyl group. In particular, as will be described later, when using a phosphate ester-based surfactant, a fatty acid salt, a polysaccharide fiber having a compound having a phosphate group, which is a similar compound, a polysaccharide fiber having a compound having a carboxyl group, It is more preferable to use it.

Further, the content of the polysaccharide fiber is more preferably 0.01 to 5.0 mass% with respect to the total amount of the ink composition. This is because if the content of the polysaccharide fiber is less than 0.01% by mass, it is difficult to suppress ink leakage, and if it exceeds 5.0% by mass, the ink viscosity tends to be high, and the writing feel and dry-up performance are improved. This is because it is likely to be affected. Considering more, 0.1 to 2.0 mass% is preferable, and 0.1 to 1.0 mass% is more preferable.

A shear thinning agent may be used as an ink viscosity modifier other than the polysaccharide fiber. Examples of the shear thinning agent include cross-linked acrylic acid polymers, xanthan gum, welan gum, succinoglycan, guar gum, locust bean gum, λ-carrageenan, cellulose derivatives, and polysaccharides such as diutan gum. The polysaccharide is preferably used in consideration of the compatibility and the ink leakage suppression effect when used in combination with the polysaccharide fiber, and xanthan gum and succinoglycan are preferably used in consideration of the ink leakage suppression effect. preferable. These shear thinning agents may be used alone or in combination of two or more.

The colorant used in the present invention is not particularly limited, and examples of the pigment include inorganic, organic, and processed pigments. Specifically, carbon black, aniline black, ultramarine blue, yellow lead, titanium oxide, iron oxide, Phthalocyanine-based, azo-based, quinacridone-based, quinophthalone-based, slene-based, triphenylmethane-based, perinone-based, perylene-based, gioxazine-based, microcapsules, aluminum pigments, pearl pigments, fluorescent pigments, phosphorescent pigments, complementary color pigments .. As the dye, a direct dye, an acid dye, a basic dye, a metal-containing dye, and various salt-forming dyes 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 as in the present invention, when the organic resin particles are in close contact with each other and a gap is generated between the organic resin particles, ink leakage may be affected. This is because by filling the gap with pigment particles having an average particle diameter of 1 μm or less, the effect of suppressing ink leakage can be more easily obtained. Considering further, pigment particles having an average particle diameter of 0.5 μm or less can be obtained. preferable. Further, with respect to the shape of the pigment particles, those having a spherical shape or an irregular shape 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 spherical shapes, and may be substantially spherical pigment particles or substantially elliptic spherical pigment particles.
The average particle diameter of the pigment particles is determined by a laser diffraction method (volume-based method based on a trade name “Microtrac HRA9320-X100”).

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 it is difficult to fill the gaps when they come into close contact with each other and a gap is generated between the organic resin particles, and ink leakage is likely to be affected. From a further consideration, the relation of Y/X<1.5 is preferable, and the relation of 0.05<Y/X<1.0 is most preferable.

Further, in order to suppress ink leakage, it is preferable to use dextrin. This is because when dextrin is used, a film is formed when the ink at the pen tip is dried, so that the space between the ball and the inner wall of the tip of the tip is formed. This is because the effect of suppressing ink leakage is obtained from the gap.

The weight average molecular weight of dextrin is more preferably 5,000 to 120,000. When the weight average molecular weight exceeds 120,000, the film formed on the pen tip is hard, and the handwriting tends to be faint when writing at the time of dry-up. On the other hand, when the weight average molecular weight is less than 5000, the hygroscopicity increases. This is because the coating tends to be easy and the pen tip tends to be soft, and it is difficult to sufficiently obtain the effect of suppressing ink leakage. Furthermore, if the weight average molecular weight is less than 20,000, the coating tends to be thin, so the weight average molecular weight of 20,000 to 120,000 is most preferable.

The content of dextrin is preferably 0.1 to 5.0 mass% with respect to the total amount of the ink composition. This is because if it is less than 0.1% by mass, the effect of ink leakage tends not to be sufficiently obtained, and if it exceeds 5.0% by mass, it tends to be difficult to dissolve in the ink. From the viewpoint of solubility in ink, 0.1 to 3.0 mass% is preferable, and from the viewpoint of ink leakage, 1.0 to 3.0 mass% is most preferable.

A water-soluble solvent is used in consideration of water dissolution stability and prevention of water evaporation and drying. Polyhydric alcohol solvent 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 other glycol ether solvents. Among them, it is preferable to use the polyhydric alcohol solvent in consideration of the dissolution stability with the organic resin particles used in the present invention. The polyhydric alcohol solvent is a solvent which is a compound 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 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. If so, 7.0 to 20.0 mass% or less is preferable, because the hydrogen bond due to the solvent makes it easier for the agglomerate structure to collapse, and the ink leakage suppressing effect due to the organic resin particles is likely to be affected.

Further, by improving lubricity, it is possible to use a phosphoric acid ester-based surfactant, a fatty acid, etc. in order to smooth the rotation of the ball, thereby suppressing the wear of the ball seat and improving the writing quality. preferable. In particular, it is preferable to use a phosphate ester type surfactant having a phosphate group. This is because the phosphate group is adsorbed on the metal, whereby the lubricity is further improved, and the wear of the ball seat is suppressed and the writing quality is easily improved. Examples of the phosphoric acid ester-based surfactant include styrenated phenol-based, nonylphenol-based, lauryl alcohol-based, tridecyl alcohol-based, octylphenol-based, and hexanol-based surfactants. Among these, the use of a phosphoric acid ester-based surfactant having no phenyl skeleton is preferable because the phenyl skeleton tends to affect the lubricity due to steric hindrance. You may use these individually or in mixture of 2 or more types.

Specific examples of the phosphate ester-based surfactant include Plysurf A212C (tridecyl alcohol-based), A208B (lauryl alcohol-based), and PLYSURF A212C (Daiichi Kogyo Seiyaku Co., Ltd.). Examples include A213B (lauryl alcohol type), A208F (short chain alcohol type), A215C (tridecyl alcohol type), and A219B (lauryl alcohol type). Further, specific examples of the fatty acid include OS soap, NS soap, FR-14, FR-25 (Kao Corporation) and the like. These phosphate ester-based surfactants and fatty acids may be used alone or in admixture of two or more.

Further, in order to obtain a thicker handwriting using pigment particles, one or more kinds of surfactants selected from silicone-based surfactants, acetylene glycol-based surfactants, fluorine-based surfactants and dialkylsulfosuccinates are used. It is preferable. This is because the penetrability into paper is improved and the pigment particles are left on the paper surface, so that a darker and clear handwriting is easily obtained. Therefore, it is easy to obtain deeper and clearer handwriting by setting the amount of movement of the ball of the ball-point pen tip in the direction of the vertical axis to be 15 to 50 μm or more and increasing the ink discharge amount and using the surfactant. Among them, it is preferable to use a fluorine-based surfactant. This is because the fluorine-based surfactant can reduce the surface tension most, and the penetrability into paper is easily improved, so that a strong handwriting is obtained. This is because it is easy to obtain.

Examples of the silicone-based surfactant include polyether modified, methylstyryl modified, alkyl modified, higher fatty acid ester modified, hydrophilic special modified, fluorine modified, and silicone oil such as dimethyl and methylphenyl. Fluorine-based surfactants 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, perfluoro group. Examples thereof include a fluoro group/hydrophilic group/lipophilic group-containing oligomer, a perfluoro group/hydrophilic group-containing oligomer, a perfluoro group/lipophilic group-containing oligomer, a perfluoroalkyl betaine, and a perfluoroalkylamine oxide compound. Among them, it is preferable to use a perfluoroalkylethylene oxide adduct. The perfluoroalkylethylene oxide adduct fluorosurfactant can be preferably used because it can easily make darker handwriting. Furthermore, the presence of the ethylene oxide group causes the hydrophilicity to become stronger, so that the ethylene oxide group is more likely to be dissolved in water and tends to have stable temporal stability. You may use these individually or in mixture of 2 or more types.

Other additives may optionally contain additives, specifically, a pH adjusting agent, an acrylic resin emulsion, and a urethane resin emulsion for improving the temporal stability and lubricity of the colorant. , Fixing agents such as styrene-butadiene resin emulsions, pigment dispersants such as acidic resins, antibacterial agents such as 1,2-benzisothiazolin-3-one, moisturizers such as urea and sorbit, rust preventives 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.

In the present invention, the ink consumption per 100 m is A (mg), and the ball diameter is B (mm) in order to make the water-based ballpoint pen that is more excellent in writing quality and has a strong handwriting while suppressing the leakage of ink. In this case, it is preferable that the relation 110≦A/B≦600 is satisfied. By setting this range, not only the writing quality is improved with dark handwriting, but also handwriting smearing and good writing performance without crying fluff are achieved. The effect of making it easier to get is obtained.

Further, regarding the relationship between the ink consumption amount per 100 m and the ball diameter, it is preferable to set 120≦A/B in order to improve the darker handwriting and writing quality. It is preferable that A/B≦500 in order to prevent ink dripping from the gap at the tip of the tip, bleeding, and crying flicker, and to improve writing performance. Therefore, it is preferable that 120≦A/B≦500, and it is preferable that 150≦A/B≦450 in consideration of darker handwriting and ink leakage suppression. As a specific example, when the ball diameter is A (mm) = 1.0 (mm), the ink consumption amount B (mg) per 100 m is B = 110 to 600 (mg), The relationship may be 110≦A/B≦600. Regarding the ink consumption, a spiral of 5 test samples was used at a writing speed of 4 m/min at a writing angle of 65° on a writing paper JIS P3201 writing paper and a writing load of 100 g. A writing test is performed, and the average value of the ink consumption per 100 m is defined as the ink consumption per 100 m.
The ball diameter is not particularly limited, but a ball of about 0.1 to 2.0 (mm) is used.

Moreover, about pH, 7.0-11.0 are preferable. This is because when the pH value is less than 7 and in the acidic region, the stability of ink components such as organic resin particles, colorants and surfactants, and the corrosion of metal ball-point pen tips and balls occur. This is because even if the pH value exceeds 10 and approaches the strong alkaline side, the stability of the ink components is similarly affected. From a further consideration, a pH value of 7.0 to 10.0 is more preferable.

Further, in order to further improve the lubricity and obtain a deep handwriting, it is more preferable to set the arithmetic average roughness (Ra) of the ball surface to 0.1 to 5 nm. This is because when the arithmetic average roughness (Ra) exceeds this range, the ball surface is too rough and the rolling resistance of the ball and the ball seat tends to increase, so that the writing feel tends to be poor. Below the range, the ink is not sufficiently deposited on the surface of the ball, and it becomes more difficult to obtain thick handwriting. Therefore, in order to improve the writing feel and obtain a deep handwriting, the arithmetic average roughness (Ra) of the ball surface is preferably 0.1 to 5 nm. Further, in consideration, it is preferable that the arithmetic mean roughness (Ra) of the ball surface is 0.1 to 4 nm.

Regarding the arithmetic mean roughness of the ball surface, the arithmetic mean roughness (Ra) means (from the roughness curve measured by a surface roughness measuring instrument (model name SPI3800N manufactured by Seiko Epson Corporation) in the direction of the mean line. This is a value obtained by sampling the reference length, summing the absolute values of the deviations from the average line of this sampling portion to the measurement curve, and averaging.

Further, the ball material is not particularly limited, but examples thereof include a cemented carbide ball containing tungsten carbide as a main component, silicon carbide, alumina, zirconia, and silicon nitride. In particular, a cemented carbide ball is preferable because it is low in cost, moreover, the ink easily deposits on the surface of the ball, and it is advantageous when writing on a writing surface on which hand grease is adhered.

Next, the present invention will be described with reference to examples.
Example 1
Pigment dispersion (colored resin particles: average particle size 0.4 μm, solid content 30%) 20.0 parts by mass
Water 58.7 parts by mass
Olefin resin particles (low density polyethylene dispersion, average particle size 6 μm, pH value 8, solid content 40%) 0.5 parts by mass Polyhydric alcohol (glycerin) 10.0 parts by mass
Dextrin (weight average molecular weight: 100,000) 1.0 part by mass
5.0 parts by mass of urea
PH adjuster (triethanolamine) 2.0 parts by mass
0.5 parts by mass of ethylenediaminetetraacetic acid (EDTA)
Lubricant (phosphate ester type surfactant) 1.0 part by mass
Antirust agent (benzotriazole) 0.5 parts by mass
Polysaccharide fiber (cellulose nanofiber) 0.3 parts by mass

The pigment dispersion, water, organic resin particles, polyhydric alcohol solvent, dextrin, urea, pH adjuster, ethylenediaminetetraacetic acid, lubricant and rust preventive were heated and stirred with a magnet hot stirrer to prepare a base ink.

Then, while heating the above-prepared base ink, the polysaccharide fiber was added and sufficiently mixed and stirred using a homogenizer stirrer until a uniform state was obtained, to obtain an aqueous ballpoint pen ink composition of Example 1. It was
The ink viscosity of Example 1 was measured with a Brookfield DV-II viscometer (CPE-42 rotor) at a shear rate of 1.92 sec ⁻¹ (rotation speed 0.5 rpm) under an environment of 20° C. When the ink viscosity was measured under the conditions, it was 500 mPa·s.
Further, the pH value of Example 1 was measured at 20° C. using an IM-40S type pH meter (manufactured by Toa DKK Co., Ltd.), and was pH value=8.5.

Examples 2-16
Aqueous ink compositions for water-based ballpoint pens of Examples 2 to 16 were obtained in the same procedure as in Example 1 except that the ink formulation was changed as shown in the table. The table shows the ink formulation and the evaluation results.

Comparative Examples 1-9
Aqueous ink compositions for water-based ballpoint pens of Comparative Examples 1 to 9 were obtained in the same procedure as in Example 1 except that the ink formulation was changed as shown in the table. The table shows the ink formulation and the evaluation results.

Testing and evaluation
The ink compositions for water-based ball-point pens prepared in Examples 1 to 16 and Comparative Examples 1 to 9 were ball-tip chips (balls of ball-point pen chips) in which a ball having a diameter of 0.7 mm was rotatably held at the tip of an ink container. 30 μm in the direction of the ordinate and the arithmetic mean roughness (Ra) of the ball surface (Ra) of 1 nm) filled in the ink container (made of polypropylene) equipped with the chip holder via the refill (1.0 g). ) A gel ink ballpoint pen (trade name: G-knock) manufactured by Pilot Corporation was attached, and the following tests and evaluations were performed. The abrasion resistance test (suppression of abrasion of the ball seat) and the evaluation of the handwriting density were performed by using JIS P3201 Writing Paper A as a writing test paper and the following test method.

Ink leakage test: A 40g weight was attached to a gel ink ballpoint pen, the ballpoint pen tip was made to protrude and faced downward, and the state where the ball of the ballpoint pen tip was in contact with the bottom of the display case for a ballpoint pen was maintained at 20°C, 65%RH. The sample was allowed to stand for 1 day in the above environment, and the amount of ink leakage from the tip of the ballpoint pen tip was measured.
Ink leakage is less than 5 mg
Ink leakage amount is 5 to 20 mg ・・・○
Ink leakage exceeding 20 mg and less than 30 mg... △
Ink leakage amount of 30 mg or more ・・・ ×

Writing quality: A sensory test by handwriting was performed and evaluated.
Very smooth... ◎
Smooth ・・・○
A level of smoothness that is not a problem in practice... △
Heavy things...×

Darkness of handwriting: I observed handwriting written by handwriting.
Thick and clear handwriting...◎
Thick handwriting...○
It is a handwriting with sufficient depth for practical use. △
Thin handwriting...×

From the results in the table, in Examples 1 to 16, good performances were obtained in the ink leakage test, writing quality, and handwriting density. When the ink compositions for water-based ballpoint pens of Examples 1 to 16 were 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, the ink leakage test, writing quality, and handwriting A good level of performance was obtained in terms of both thickness and thickness.
A spiral writing test was conducted using the aqueous ball-point pen ink composition of Example 1 as an aqueous ball-point pen, and the ink consumption per 100 m was A (mg) and the ball diameter was B (mm). =170 (mg), the ball diameter was B=0.7 (mm), and A/B=243.

Further, the ink compositions for water-based ball-point pens of Examples 1 to 16 were tested with a gel ink ball-point pen having a ball-point pen tip having a ball diameter of 1.0 mm. As a result, good writing performance was obtained. Therefore, when using a ball having a ball diameter of 0.9 mm or more and increasing the ink discharge amount, there is a large gap between the ball and the inner wall of the tip of the chip, and the influence of ink leakage easily occurs. The effect of is remarkable and is preferably used.

In Comparative Examples 1 and 2, since the polysaccharide fiber was not used, the ink leakage was severe, which was a practical problem.

In Comparative Example 3, since no organic resin particles were used, the ink leakage was severe, which was a practical problem.

In Comparative Examples 4 and 5, the amount of movement of the ball of the ball-point pen tip in the direction of the vertical axis was less than 15 μm, so the amount of ink discharged was small, resulting in a thin handwriting.

In Comparative Example 6, the amount of movement of the ball of the ball-point pen tip in the direction of the vertical axis exceeded 50 μm, so the amount of ink discharge increased, crying was generated on the handwriting, and ink leakage could not be suppressed.

In Comparative Examples 7 to 9, since the inorganic resin particles were used, the ink leakage was severe, which was a practical problem.

Generally, in order to suppress ink leakage, a ballpoint pen tip of a water-based gel ballpoint pen holds a ball rotatably held at the tip of the ballpoint pen tip at the tip end edge of the tip end directly or through a pressing body by an elastic member such as a coil spring. It is equipped with 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 during writing to allow the ink to flow out, and even the minute gap at the tip of the tip is closed when not in use. When an ink composition for a ballpoint pen having a particularly high effect of suppressing ink leakage as in the invention is used, ink leakage can be suppressed even without the elastic member such as the coil spring. Therefore, there is no resistance between the ball and the elastic member, the writing feel is improved, and the fluidity of the ink is also improved, so that the ink followability is also improved, which leads to a reduction in the number of parts and can reduce costs. And is more effective. In particular, in a retractable ballpoint pen, it is more important to suppress ink leakage, so that it can be preferably used.

INDUSTRIAL APPLICABILITY The present invention can be used as an ink composition for a water-based ballpoint pen, and more specifically, it is widely used as a cap type, a retractable type ballpoint pen filled with the water-based ballpoint pen ink composition, a marker, a fountain pen, etc. can do.

Claims (7)

A water-based ball-point pen having a ball-point pen tip at the tip of the ink containing cylinder and containing an ink composition for a water-based ball-point pen in the ink containing cylinder, wherein the amount of movement of the ball of the ball-point pen tip in the longitudinal direction is 15 to 50 μm, and the aqueous ink composition for a ballpoint pen contains water, a coloring agent, organic resin particles, and a polysaccharide fiber, and the polysaccharide fiber is a compound having a phosphate group, or carboxyl. Cellulose fibers surface-treated with a compound having a group, where 120≦A/B≦500 when the ink consumption per 100 m of the water-based ballpoint pen is A (mg) and the ball diameter is B (mm). A water-based ballpoint pen characterized by that. Content of the said polysaccharide fiber is 0.01-5.0 mass% with respect to the ink composition whole quantity, The water-based ball-point pen of Claim 1 characterized by the above-mentioned. The water-based ballpoint pen according to claim 1, wherein the organic resin particles are olefin resin particles or nitrogen-containing resin particles. The water-based ballpoint pen according to any one of claims 1 to 3, wherein the water-based ballpoint pen ink composition contains a phosphoric acid ester-based surfactant or a fatty acid. The water-based ballpoint pen according to any one of claims 1 to 4, wherein the water-based ballpoint pen ink composition contains dextrin. The water-based ballpoint pen according to any one of claims 1 to 5, wherein the colorant is pigment particles. A retractable water-based ballpoint pen according to any one of claims 1 to 6 , wherein the tip end portion of the ballpoint pen tip is retractable from the tip end portion of the barrel by slidably disposing the ballpoint pen according to any one of claims 1 to 6. A water-based ballpoint pen characterized by being a ballpoint pen.