JP6998438B2 - Ink composition for water-based ballpoint pen and water-based ballpoint pen using it - Google Patents

Description

The present invention relates to an ink composition for a water-based ballpoint pen, and more particularly to an ink composition for a water-based ballpoint pen having good handwriting drying property and writing quality, and a water-based ballpoint pen using the same.

The ink composition for a water-based ballpoint pen is an ink composition using water as a main solvent. For this reason, if the pen tip is exposed to the atmosphere for a while, water, which is the main solvent, evaporates from the pen tip, the ink viscosity becomes high, the writing marks become faint, and the water evaporates and the ink progresses. Has been confirmed to dry and solidify, and the ink flow path of the writing instrument is clogged, making writing impossible. In particular, when it is used for a haunting type ballpoint pen, this phenomenon is remarkably likely to occur because the pen tip is always exposed to the atmosphere. Therefore, in order to suppress the evaporation of water in the ink composition, it is generally practiced to add a polyhydric alcohol solvent such as glycerin or ethylene glycol as a moisturizer. However, although there is a tendency to suppress the evaporation of water from the ink, the obtained handwriting requires time to completely dry, so if you touch a undried handwriting, the writing surface may become dirty or the handwriting may become dirty. It has a problem that it becomes dirty.
In order to solve such a problem, Patent Document 1 discloses an ink composition containing 1,4-cyclohexanedimethanol and one or more of ethyl alcohol, n-propyl alcohol and isopropyl alcohol. Patent Document 2 discloses an ink composition containing dioctyl sulphosuccinate, and Patent Document 3 discloses an ink composition containing a fluorine-based surfactant, which is a water-based ink. Many ink compositions have been proposed in which the surface tension of the composition is lowered to improve the permeability to the paper surface.

However, although the ink composition of Patent Document 1 improves the drying property of handwriting, it has a problem of stability over time because it has a strange odor peculiar to an alcohol solvent and is highly volatile. Further, in the ink composition of Patent Document 2, although the dryness of the handwriting tends to be improved, it cannot be said that it is sufficient, and it is difficult to obtain a good handwriting.

Further, when an ink composition such as Patent Documents 2 and 3 is used for a ballpoint pen, although the permeability to the paper surface is improved to some extent, it is desired to further improve the handwriting drying property and the lubricity. Further, the wettability to the ballpoint pen tip is also improved, and the ink easily leaks from the pen tip, so that the ink composition for a water-based ballpoint pen is not sufficiently satisfactory.

Recently, ballpoint pens are often lined up in a display case, and in the case of a ballpoint pen in a cap-off state such as a haunting ballpoint pen, if the ballpoint pen tip is returned to the display case with the ballpoint pen protruding, a trial writing etc. is performed. As the ballpoint pens were repeatedly returned to the display case, a number of ballpoint pens were stacked on top of the first returned ballpoint pens, and as a result, the weight of the stacked ballpoint pens caused the balls and tip tips. A gap is created between the ballpoint pen and the inner wall of the ballpoint pen, ink drips from the gap, ink leaks, and the display case is soiled, and other ballpoint pens inside the case are also likely to become dirty. Is desired at the same time.

Japanese Unexamined Patent Publication No. 2000-319570 Japanese Unexamined Patent Publication No. 2005-238672 Japanese Unexamined Patent Publication No. 2004-224892

The present invention is to obtain an ink composition for a water-based ballpoint pen that improves handwriting dryness and improves writing quality, and a water-based ballpoint pen using the same.

The present invention is to solve the above problems.
"1. An ink composition for an aqueous ball pen containing water, a colorant, a surfactant, and an alkali swelling-associating thickener, wherein the surfactant has an acetylene bond in the structure, or The silicone-based surfactant having an acetylene bond in the structure has an ethylene oxide-added molar number of 8 or less, an HLB value of 3 to 14, and a weight average molecular weight of the silicone-based surfactant. An ink composition for a water-based ball pen, characterized by being 500 to 2000.
2. 2. The ink composition for a water-based ballpoint pen according to Item 1, wherein the ink composition for a water-based ballpoint pen contains a phosphoric acid ester-based surfactant.
3. 3. The ink composition for a water-based ballpoint pen according to item 1 or 2, wherein the colorant is a pigment.
4. The ink composition for an aqueous ballpoint pen according to any one of Items 1 to 3, wherein the surfactant having an acetylene bond in the structure is added with propylene oxide.
5. A ballpoint pen tip that rotatably holds a ball is held at the tip of an ink containing cylinder, and the ink composition for a water-based ballpoint pen according to any one of items 1 to 4 is contained in the ink containing cylinder. A water-based ballpoint pen that is characterized by being made of ink.
6. The water-based ballpoint pen according to Item 5, wherein the amount of movement of the ball of the ballpoint pen tip of the water-based ballpoint pen in the vertical axis direction is 20 to 45 μm. ".

INDUSTRIAL APPLICABILITY The present invention obtains an ink composition for a water-based ballpoint pen, which improves handwriting drying property by improving the permeability to a paper surface, and improves the writing quality by improving lubricity, and a water-based ballpoint pen using the same. be able to.

The feature of the present invention is that a surfactant having an acetylene bond in the structure or a silicone-based surfactant is used as the surfactant, and the surfactant having the acetylene bond in the structure has an ethylene oxide addition molar number of 8. In the following, the HLB value is 3 to 14, the weight average molecular weight of the silicone-based surfactant is 500 to 2000, and by using an alkali swelling association type thickener as the thickener, the writing property is dry. It is possible to improve the writing quality by improving the lubricity.

The surfactant used in the present invention is a surfactant having an acetylene bond in the structure having an ethylene oxide addition molar number of 8 or less and an HLB value of 3 to 14, or a silicone having a weight average molecular weight of 500 to 2000. By using a system-based surfactant, the permeability to the paper surface can be improved, the handwriting dryness can be improved, and the writing quality can be improved. Furthermore, by using an alkali swelling association type thickener, it is possible to improve the writing quality. It was found to improve the dryness of handwriting.

As the surfactant, a surfactant having an acetylene bond in the structure having an ethylene oxide addition molar number of 8 or less and an HLB value of 3 to 14, or a silicone-based surfactant having a weight average molecular weight of 500 to 2000. The dryness of the brush stroke can be improved by using the above-mentioned, and the dryness of the brush stroke can be further improved by using the above-mentioned alkali swelling association type thickener in combination. The alkaline swelling-associating thickener has a hydrophilic group as a skeleton and has a hydrophobic group at a side chain or a terminal, and when a pigment is used, the hydrophobic group of the alkaline swelling-associating thickener is used. Adsorbs to the pigment to form a mutual structure between the pigment and the associated thickener in the ink. Therefore, at the time of writing, the pigment having a mutual structure and the alkali swelling association type thickener rapidly permeate the paper surface by the surfactant having the acetylene bond in the structure or the silicone-based surfactant. It is presumed that the mutual structure is fixed on the paper surface in a state of being partially entangled with the paper fiber in three dimensions. Since each component in the ink acts as a penetrant and a fixing agent to improve the abrasion resistance, the handwriting drying property is likely to be improved.
As described above, an alkali swelling association type thickener, a surfactant having an acetylene bond in the structure having an ethylene oxide addition molar number of 8 or less and an HLB value of 3 to 14, or a weight average molecular weight of 500 to By using it in combination with a silicone-based surfactant of 2000, a special effect of dryness of handwriting can be obtained, which is an important configuration.

<Alkaline swelling association type thickener>
The alkaline swelling association type thickener is an association type resin capable of increasing the viscosity by dissolving or swelling by neutralizing and dissociating the carboxyl group by adding the alkaline agent. The alkaline swelling association type thickener has an effect of improving handwriting drying property in addition to the effect of the surfactant. The alkaline swelling-associating thickener has a hydrophilic group as a skeleton and has a hydrophobic group at a side chain or a terminal, and when a pigment is used, the hydrophobicity of the alkaline swelling-associating thickener. Adhesion of the group to the pigment forms a mutual structure between the pigment and the associated thickener in the ink. At the time of writing, the pigment and the associative thickener having a mutual structure formed by the surfactant having the acetylene bond in the structure or the silicone-based surfactant rapidly permeate the paper surface and the mutual structure is made of paper. It is presumed that it is fixed on the paper in a state where it is partially entwined with the fibers in three dimensions. Since each component in the ink acts as a penetrant and a fixing agent to improve the abrasion resistance, the handwriting drying property is likely to be improved. Further, the thickener has a hydrophobic group adsorbed on the pigment and also functions as a dispersant, so that the pigment dispersibility is easily improved.

Further, the alkaline swelling association type thickener has a hydrophilic group as a skeleton and has a hydrophobic group at a side chain or a terminal, and one of the hydrophobic groups is adsorbed on particles or the like in an aqueous medium, and further. It is a thickener that can obtain the thickening effect of ink by forming a weak cross-linking structure by adsorbing the other hydrophobic group with other particles or other hydrophobic groups. The slime is an alkali swelling association type thickener.

Further, when the pigment and the organic resin particles described later are used in the association type thickener, the hydrophobic group of the association type thickener is adsorbed on the pigment and the organic resin particles described later in three dimensions. Since the structure is formed, it is easy to obtain the effect of suppressing ink leakage even when the ink viscosity is low. Further, the alkali swelling association type thickener has a high ink viscosity development efficiency among the association type thickeners, and further, when the pigment and the organic resin particles are used, the adsorptivity to the pigment and the organic resin particles is higher. Since it is easy to form a crosslinked structure and a three-dimensional structure is formed, it is preferable to use it in combination with the surfactant because it is easy to improve the dryness of handwriting and to suppress ink leakage.

The alkali swelling association type thickener is a polymerizable resin of a monomer or a copolymer containing various polymerizable monomers having a carboxyl group such as acrylic acid, methacrylic acid, maleic acid, etc. as a mechanism of exhibiting alkali swelling property. However, by improving the dryness of the brush stroke and having stable swelling property for a long period of time, it can be expected to have the effect of suppressing ink leakage and further improving the dispersibility of the pigment to easily improve the stability of the ink over time. Particularly, those composed of three kinds of monomers, vinyl acetate, methyl methacrylate, and methacrylic acid, are preferable.

Further, since the alkaline swelling association type thickener swells by neutralizing with an alkali, it is preferable to use an alkaline pH adjuster. Examples of the pH adjuster include alkanolamines such as monoethanolamine, diethanolamine, triethanolamine, dimethylethanolamine, N-methylethanolamine, N-methyldiethanolamine and diisopropanolamine, and inorganic bases such as sodium hydroxide and potassium hydroxide. And so on. When an alkaline swelling association type thickener is used, it is preferable that the pH value in the ink is alkaline with pH> 7 so that the swelling is stabilized. Further, considering the stability of the ink component such as a colorant, the pH value is preferably 11 or less, and further considering the swelling property of the alkaline swelling association type thickener, the pH value is preferably 8 or more. The value is more preferably in the range of 8-11. It is preferable to use alkanolamine to obtain the above pH value.

Further, the content of the alkaline swelling association type thickener in the ink composition is more preferably 0.01 to 5% by mass with respect to the total amount of the ink composition. This is because if the content of the alkali swelling association type thickener is less than 0.01% by mass, it is difficult to suppress ink leakage because the handwriting drying property is improved and the ink thickening effect is not sufficient. If it exceeds%, the ink viscosity tends to increase, which tends to affect the wear suppression of the ball seat, the ink followability at the time of writing, the writing quality, and the dry-up resistance. Further, more consideration is given, preferably 0.1 to 2% by mass, and most preferably 0.1 to 1% by mass.

<Surfactant having an acetylene bond in its structure>
In the ink composition of the present invention, the surfactant having an acetylene bond in the structure preferably has an ethylene oxide addition molar number of 10 or less.
The surfactant having an acetylene bond having an ethylene oxide addition molar number of 10 or less in the structure is a surfactant having an acetylene bond to which ethylene oxide is added in the structure, and the ethylene oxide addition of the surfactant is used. The number of moles is 10 or less. For example, an acetylene glycol-based surfactant having an ethylene oxide-added molar number of 10 or less, an acetylene alcohol-based surfactant having an ethylene oxide-added molar number of 10 or less, and the like can be mentioned.
The surfactant having an acetylene bond in the structure having an ethylene oxide addition molar number of 10 or less can significantly improve the permeability to the paper surface. Therefore, the ink composition containing the surfactant having the acetylene bond in the structure can quickly penetrate into the paper, and thus the time until the obtained handwriting is completely dried is obtained. It is shortened and has excellent handwriting drying property, which can prevent the paper surface and the handwriting itself from being rubbed and soiled. In particular, by using the alkaline swelling association type thickener and a surfactant having an acetylene bond having an ethylene oxide addition molar number of 10 or less in the structure in combination, the effect of further improving the handwriting drying property can be obtained. Therefore, it is effective.

This is because, for unknown reasons, a surfactant having an acetylene bond in the structure having an ethylene oxide addition molar number of 10 or less can preferably maintain a good balance between hydrophobicity and hydrophilicity.
In order for the ink composition to quickly penetrate the paper surface after writing, it is necessary to appropriately control the surface tension of the ink composition after writing. In order to instantly control the surface tension associated with the writing operation, that is, the so-called dynamic surface tension, and to obtain rapid permeability to the paper surface, the behavior of the surfactant molecule in the ink is important. Surfactant molecules are rapidly arranged at the gas-liquid interface under dynamic conditions, and it is possible to control the surface tension instantly and effectively by using a surfactant having a specific structure. An ink composition having excellent brush stroke drying property can be obtained.
If the hydrophilicity of the surfactant having an acetylene bond in the structure is too high, the solubility in the ink composition becomes too high, and it is difficult to quickly arrange the surfactant molecules on the gas-liquid interface, and it is difficult to quickly arrange the surfactant molecules on the paper surface. Permeability tends to be difficult to improve. On the contrary, if the hydrophobicity of the surfactant having an acetylene bond in the structure is too high, the solubility in the ink composition becomes too low, and it is difficult to improve the permeability to the paper surface, and also due to separation and the like. The stability to the ink composition tends to be inferior.
Since a surfactant having an acetylene bond having an ethylene oxide addition molar number of 10 or less in its structure maintains a balance between hydrophilicity and hydrophobicity, when the surfactant is used, the active agent molecule is gas-liquid. Since it is properly arranged at the interface, the surface tension of the ink composition is controlled and the permeability of the ink composition into paper is improved. Therefore, it is presumed that the ink composition containing a surfactant having an acetylene bond in the structure having an ethylene oxide addition mole number of 10 or less has improved permeability to the paper surface and excellent handwriting drying property. ..

In addition, a surfactant having an acetylene bond having an ethylene oxide addition molar number of 10 or less in its structure has the effect of improving the writing quality, such as improving the handwriting dryness and at the same time providing a smooth writing taste. .. This is because the ink composition contains a surfactant having the acetylene bond in the structure, so that the lubricity between the ball and the ballpoint pen tip of the ballpoint pen is improved, and the ballpoint pen is worn. This is because it can be suppressed.
The ink composition of the present invention containing a surfactant having an acetylene bond in its structure can contain other lubricants, and is particularly described later among the lubricants. It is preferable to use it in combination with a phosphoric acid ester-based surfactant.

In the present invention, it is preferable that the number of moles of ethylene oxide added to the surfactant having an acetylene bond in the structure is 10 or less, but this becomes more hydrophilic when the number of moles of ethylene oxide added exceeds 10. This is because the solubility tends to be high, the rapid arrangement of the surfactant on the interface tends to be impaired, and the improvement of the writing dryness tends to be limited. Further, considering the improvement of the effect by the surfactant having the acetylene bond in the structure, the number of moles of ethylene oxide added is preferably 8 or less. Furthermore, the number of moles of ethylene oxide added is preferably 4 or more. When the number of moles of ethylene oxide added is 4 or more, it is possible to prevent the solubility from being lowered and the ink composition from becoming stable and difficult to be present, and the effect of the surfactant from being lowered over time.

Further, propylene oxide may be further added to the surfactant having an acetylene bond in the structure used in the present invention. In consideration of further improvement in handwriting drying property and stability over time of ink, in the present invention, it is possible to select and use a surfactant having an acetylene bond to which ethylene oxide and propylene oxide are added in the structure. preferable.
This is because when a surfactant having an acetylene bond in the structure is added with ethylenelene oxide and propylene oxide, the balance between hydrophobicity and hydrophilicity is more preferably maintained.
As described above, in order to have an acetylene bond in the structure and obtain the effect of the surfactant, it is preferable that the balance between hydrophilicity and hydrophobicity is appropriately maintained.
A surfactant having an acetylene bond to which both ethylene oxide and propylene oxide are added in the structure makes it easier to maintain a more suitable balance between hydrophilicity and hydrophobicity. The activator molecules are rapidly arranged at the gas-liquid interface while being very stable in the composition. Therefore, the surface tension of the ink composition is quickly controlled, and the permeability of the ink composition to paper tends to be quickly improved. Therefore, in the present invention, by using a surfactant having ethylene oxide and an acetylene bond to which propylene oxide is added in the structure, the handwriting drying property is further improved and the ink composition is also excellent in ink stability over time. It is preferable because the product can be provided.
In particular, when a pigment and an alkaline swelling-associating thickener are used as described above, an interface to which both the pigment and the alkaline swelling-associating thickener forming a mutual structure and the ethylene oxide and propylene oxide are added. The activator quickly penetrates into the paper surface, and the mutual structure is easily fixed on the paper surface in a state of being partially entangled with the paper fiber in three dimensions, and it is easy to improve the writing dryness.

The ratio of the number of moles of ethylene oxide added to the number of moles of propylene oxide added keeps a good balance between the hydrophobicity and hydrophilicity of the surfactant having an acetylene bond in the structure. Number of moles added: The number of moles added with propylene oxide is preferably 1: 1 to 5: 1.
Further, considering the arrangement to the gas-liquid interface, it is preferable that the total number of moles of ethylene oxide added and the number of moles of propylene oxide added is 10 or less. If the number of added moles is too large, the surfactant molecule becomes too long and tends to cause steric hindrance when arranging at the gas-liquid interface. It is particularly preferable because an effect of maintaining a good balance between hydrophobicity and hydrophilicity and considering the influence of steric hindrance at the time of arrangement on the gas-liquid interface can be obtained.
Further, in consideration of improvement of handwriting drying property and stability of the ink over time, a surfactant having the acetylene bond having an ethylene oxide addition mole number of 5 and a propylene oxide addition mole number of 2 in the structure is used. Is more preferable.

Further, considering the arrangement to the gas-liquid interface, it is preferable that the total number of moles of ethylene oxide added and the number of moles of propylene oxide added is 10 or less. If the number of added moles is too large, the surfactant molecule becomes too long and tends to cause steric hindrance when arranging at the gas-liquid interface. It is particularly preferable because an effect of maintaining a good balance between hydrophobicity and hydrophilicity and considering the influence of steric hindrance at the time of arrangement on the gas-liquid interface can be obtained.
Further, in consideration of improvement of handwriting drying property and stability of the ink over time, a surfactant having the acetylene bond having an ethylene oxide addition mole number of 5 and a propylene oxide addition mole number of 2 in the structure is used. Is more preferable.

The HLB value of the surfactant having an acetylene bond in the structure is preferably 3 to 14, more preferably 6 to 12, and particularly preferably 7 to 9. When the HLB value of the surfactant having the acetylene bond in the structure is 3 or more, the surfactant can be stably present without remaining dissolved in water as a solvent, and the effect can be obtained at the initial stage and over time. It is preferable that the content is 14 or less because the hydrophobicity tends to make it easy to arrange in the vicinity of the gas-liquid interface, and the effect brought about by the surfactant such as improvement of handwriting dryness can be obtained in a small amount and instantly. ..

Examples of the surfactant having an acetylene bond in the structure include an acetylene alcohol-based surfactant and an acetylene glycol-based surfactant, which improve the permeability to the paper surface and improve the writing dryness. Considering that it is easy to use, it is preferable to use an acetylene glycol-based surfactant.

<Silicone-based surfactant>
The silicone-based surfactant is suitable by balancing it with a Si skeleton in the structure, a hydrophobic group such as propylene oxide, and a hydrophilic group such as ethylene oxide, so that the active agent is stable in the ink. Since the molecules are easily arranged at the gas-liquid interface, the surface tension of the ink is quickly controlled during writing to improve the permeability, and it is easy to obtain excellent ink that achieves both handwriting dryness and ink stability over time. Become. Among the silicone-based surfactants, the weight average molecular weight is preferably 500 to 3000. This is because when the weight average molecular weight of the above-mentioned surfactant exceeds 3000, the molecules of the silicone-based surfactant tend to become too large and the arrangement at the gas-liquid interface tends to be delayed. Therefore, the dryness of the brush stroke may not be sufficient. On the other hand, when the weight average molecular weight is 3000 or less, the molecules of the silicone-based surfactant tend to be relatively small, so that the activator molecules tend to be rapidly arranged on the gas-liquid interface, and the writing property is dry. Easy to improve. Further, when the weight average molecular weight is less than 500, it is difficult to obtain the desired handwriting drying property. Considering the above effects, the weight average molecular weight is preferably 500 to 3000, more preferably the weight average molecular weight is 500 to 2000, and further considering the weight average molecular weight is 1000 to 2000. Is preferable.
In particular, the combined use of the alkaline swelling association type thickener and the silicone-based surfactant is effective because the effect of further improving the handwriting drying property can be obtained.

In addition, the silicone-based surfactant has the effect of improving the writing quality, such as improving the handwriting drying property and at the same time providing a smooth writing taste. This is because the ink composition contains a surfactant having the acetylene bond in the structure, so that the lubricity between the ball and the ballpoint pen tip of the ballpoint pen is improved, and the ballpoint pen is worn. This is because it can be suppressed.
The ink composition of the present invention containing a surfactant having an acetylene bond in its structure can contain other lubricants, and is particularly described later among the lubricants. It is preferable to use it in combination with a phosphoric acid ester-based surfactant.

Regarding the solubility parameter (hereinafter referred to as SP value) of the silicone-based surfactant, the SP value is preferably 8 to 13 in consideration of handwriting dryness, and the SP value is 9 to 12 in more consideration. It is preferable, and the SP value of 10 to 11 is particularly preferable. The SP value of water, which is the main component of the solvent, is 23.4, and if the SP value of the silicone-based surfactant is too close, it will be stabilized in the dissolved state, so that the arrangement of the active agent molecule on the gas-liquid interface is rapid. It tends to be difficult to achieve. When the SP value is in the above range, the activator molecules can be easily arranged at the gas-liquid interface, and stability in the ink can be obtained, which is preferable.

Specific examples of the surfactant having an acetylene bond in the structure include Orfin series (manufactured by Nisshin Kagaku Kogyo Co., Ltd.), Surfinol series, Dynol series and the like (all manufactured by Air Products Japan Co., Ltd.). ).
Specifically, regarding the silicone-based surfactant, the Sylface series (manufactured by Nisshin Chemical Industry Co., Ltd.), the BYK series (manufactured by Big Chemie Co., Ltd.), the Silsoft Spread series, and the Coatosil series (all are momentive). Performance Materials Co., Ltd.) and the like. These may be used alone or in admixture of two or more.

Further, the total content of the surfactant having the acetylene bond in the structure or the silicone-based surfactant is more preferably 0.01 to 3.0% by mass with respect to the total amount of the ink composition. This is because if the total content of the silicone-based surfactant is less than 0.01% by mass, it is difficult to obtain the desired handwriting drying property, and if it exceeds 3.0% by mass, the stability over time of the ink is affected. This is because it is easy to get out. Further, more consideration is given, preferably 0.05 to 2.0% by mass, and particularly preferably 0.1 to 1.5% by mass.

<Colorant>
The colorant used in the present invention is not particularly limited, but pigments, dyes and the like used in ink compositions for water-based ballpoint pens can be used.
In the present invention, among these colorants, it is preferable to use a pigment in consideration of excellent water resistance and light resistance and good color development.

Examples of pigments include inorganic, organic, and processed pigments, and specific examples thereof include carbon black, aniline black, ultramarine, yellow lead, titanium oxide, iron oxide, phthalocyanine, azo, quinacridone, quinophthalone, and slene. Examples thereof include based, triphenylmethane, perinone, perylene, dioxazine, microcapsules, aluminum pigments, pearl pigments, fluorescent pigments, phosphorescent pigments, complementary color pigments and the like. As the dye, a direct dye, an acid dye, a basic dye, a gold-containing dye, various salt-forming type dyes and the like can be adopted. These pigments and dyes may be used alone or in combination of two or more.
While the dye is in a dissolved state in the ink, the pigment is dispersed in the ink in an insoluble state. It is difficult to improve. However, in the present invention, it is preferable to use the above-mentioned surfactant because it can be preferably used even when a pigment is used. Further, it is preferable to use a pigment in consideration of excellent water resistance and light resistance, good color development, and an effect of suppressing ink leakage due to insolubility of the pigment.

Among those colorants, it is preferable to use a pigment having a primary average particle size of 1 to 100 nm. By setting the above range, when the silicone-based surfactant permeates the paper surface, the pigment together with the silicone-based surfactant can easily permeate into the paper surface without being caught by the fibers on the paper surface. This is because it is easy to improve the dryness of the stroke after writing, and it is easy to obtain a synergistic effect with the silicone-based surfactant, which is effective. For further consideration, it is preferable to use a pigment having a primary average particle size of 5 to 40 nm, and for further consideration, it is preferable to use a pigment having a primary average particle size of 10 to 30 nm, and it is most preferable to use a pigment having a primary average particle size of 10 to 20 nm. preferable.
The average particle size of the pigment is the particle size when the cumulative volume of the particle size distribution is 50%, which is measured by the laser diffraction method using a laser diffraction type particle size distribution measuring machine (trade name "Microtrac HRA9320-X100", Nikkiso Co., Ltd.). It can be measured by (D50).

In particular, when carbon black is used, it is preferable to use a carbon black 10% by mass aqueous dispersion having a pH value in the range of 5 to 10. This is because when the pH value is less than 5, many acidic groups are present on the surface of the carbon black, so that the carbon black exhibits hydrophilicity and dispersibility in water becomes high. In order to improve the handwriting drying property, it is preferable to obtain a certain level of fixing property on the paper surface after writing, thereby improving the abrasion resistance and easily improving the handwriting drying property. If it is less than 5, if the hydrophilicity is too high, it tends to take time to obtain the fixability due to the influence of the moisture of the ink transferred on the paper surface, and the handwriting drying property tends to be inferior. On the other hand, when the pH value is 5 or more, the pH value can be fixed on the paper surface in a relatively short time due to the synergistic effect with the surfactant, the abrasion resistance is improved, and the handwriting drying property is easily improved. The value is preferably 5 or more. Further, when the pH value exceeds 10, a strong basic group on the surface of carbon black may affect the ball of the metal material or hinder the orientation of the surfactant, and the writing quality tends to be inferior. The pH value is preferably 10 or more because it is easy to wear. Therefore, when the pH value of the carbon black 10% by mass aqueous dispersion is in the range of 5 to 10, the fixability is improved, the handwriting drying property is improved, and the effect of the surfactant is not impaired. It is preferable because the bearing does not wear and the writing quality is smooth. For further consideration, it is preferable that the pH value of the carbon black 10% by mass aqueous dispersion is in the range of 6 to 10.
As the pH value of the aqueous dispersion of 10% by mass of carbon black, the value measured by the aqueous dispersion of carbon black when the concentration of carbon black is 10% by mass is used.
The 10% by mass of carbon black aqueous dispersion can be adjusted by dispersing the carbon black in water while stirring or diluting a commercially available carbon black aqueous dispersion.

In the present invention, when a pigment is used as a colorant, an aqueous dispersion pigment product or the like which is finely and stably dispersed in an aqueous medium by using a pigment dispersant may be used in advance. Examples of the pigment dispersant include water-soluble resins, nonionic surfactants, anionic surfactants, and cationic surfactants.

The content of the colorant is preferably 1.0 to 20.0% by mass with respect to the total amount of the ink composition. If it is less than 1.0% by mass, it tends to be difficult to obtain handwriting with good color development, and if it exceeds 20.0% by mass, the solubility in ink and the stability over time due to aggregation tend to be affected. This is because, considering the tendency, 3.0 to 10.0% by mass is most preferable.

<Water>
The water is not particularly limited, and for example, ion-exchanged water, ultrafiltration water, distilled water, or the like can be used.

<Organic resin particles>
By using a surfactant having an acetylene bond in the structure or a silicone-based surfactant, the wettability of the ink composition with respect to the paper surface is improved, so that the permeability to the paper is improved and good handwriting drying is performed. You can get good writing quality and good writing quality. On the other hand, the wettability with the ball or the ballpoint pen tip is increased, and there is a possibility that ink leaks from the gap between the ball and the inner wall of the tip of the ballpoint pen tip. In particular, when the ink composition of the present invention is used for a ballpoint pen such as a haunting ballpoint pen whose pen tip is exposed and can be in a cap-off state at all times, there is a very high possibility that ink leakage may occur. It is conceivable to prevent this problem of ink leakage by increasing the ink viscosity of the ink composition, but in this case, the time until the obtained handwriting is completely dried increases, and the handwriting drying performance is inferior. Furthermore, the amount of ink consumed decreases, and the writing quality tends to be inferior.
However, the organic resin particles can effectively suppress the problem of ink leakage from the pen tip as described above, and at the same time, excellent handwriting drying property and good handwriting can be obtained. Therefore, in the present invention, it is particularly preferable to use organic resin particles. The organic resin particles can cause a physical obstacle in the gap between the ball and the inner wall of the tip of the ballpoint pen to suppress ink leakage, but the organic resin particles are harder than the inorganic particles. The ink leakage suppression effect is high because the particles are partially deformed and adhere to each other to form a weak aggregated structure.
Further, the organic resin particles not only suppress ink leakage as described above, but also can enter between the ball and the ball seat to make it difficult for them to come into direct contact with each other, thereby relaxing the rotational resistance of the ball and making the ball difficult. It is possible to suppress the wear of the seat and improve the writing quality.

As for the organic resin particles, olefin resin particles such as polyethylene resin and polypropylene resin, and organic resin particles having hydrogen-binding functional groups such as sulfonic acid group, phosphoric acid group, amino group, imino group, hydroxyl group and carboxyl group are used. It is preferable to use it.
Recently, in the case of a ballpoint pen in a cap-off state such as a haunting ballpoint pen, if the ballpoint pen tip is returned to the display case with the tip protruding, the ballpoint pen with test writing etc. is returned to the display case. As you repeat this, many ballpoint pens may be piled up on the ballpoint pen that was returned first. As a result, it is preferable to use olefin-based resin particles having a significantly higher effect of suppressing ink leakage, assuming that ink leakage due to the weight of a plurality of stacked ballpoint pens is suppressed.

This is optimized so that olefin-based resin particles do not cause problems such as insufficient ink amount while suppressing ink leakage because they are non-polar and therefore easily aggregate in water. It is presumed that the effect of suppressing ink leakage can be obtained because the aggregated structure is easily formed. Furthermore, since the olefin-based 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 easily deformed and difficult to be denatured. Since it is stable even if it is sandwiched between the ball and the ball seat, a cushioning effect can be obtained, the writing quality can be improved, and the wear of the ball seat can be suppressed, so that it can be used more preferably. By using it in combination with the silicone-based surfactant, it is possible to further improve the lubricity.

Examples of the material of the olefin resin particles include polyolefins such as polyethylene, polypropylene and polybutene, and mixtures thereof. Among these, polyethylene is preferably used in consideration of suppressing ink leakage and improving writing quality, and specifically, low-density polyethylene, high-density polyethylene, low-molecular-weight polyethylene, modified polyethylene, and modified high-density polyethylene. And so on. Among them, low-density polyethylene, low-molecular-weight polyethylene, and modified polyethylene are preferable in consideration of the effect of suppressing ink leakage. In particular, low-density polyethylene has a lower melting point than other types of polyethylene and has a soft property, so that polyethylene particles adhere to it. Low-density polyethylene is preferable because it is easy to make, it is difficult to create gaps between particles, and it is difficult for ink to leak. It can be suitably used because it improves the problem and suppresses wear of the ball seat. The olefin-based resin particles may contain a material other than the polyolefin, if necessary.

Based on the above, the ink composition of the present invention containing the surfactant or silicone-based surfactant having an acetylene bond in the structure and the alkali-swelling-associating thickener shall contain organic resin particles. Therefore, it is possible to effectively prevent ink leakage from the pen tip while maintaining excellent handwriting drying property, and it is possible to further improve the writing quality.

As the shape of the organic resin particles, spherical or irregularly shaped particles can be used, but spherical resin particles are preferable in consideration of reducing frictional resistance. The spherical resin particles referred to here are not limited to true spheres, and may be substantially spherical resin particles, substantially elliptical spherical resin particles, or the like.

When the olefin-based resin particles are used, it is preferable to use an olefin-based resin particle dispersion dispersed in water or the like in advance, but the pH value of the olefin-based resin particle dispersion is preferably 7 to 11. This is because it is easy to improve the dispersion stability of the olefin-based resin particle dispersion and the stability to ink components such as colorants and surfactants. For more consideration, a pH value of 7 to 10 is more preferable.

Further, the content of the organic resin particles is more preferably 0.01 to 10.0% by 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 aggregated structure tends to be strong, and the writing quality and dry-up performance are improved. This is because it is easily affected. Further, more consideration is given, preferably 0.02 to 5.0% by mass, particularly preferably 0.03 to 1.0% by mass, and most preferably 0.05 to 0.5% by mass.

In addition, a water-soluble solvent is used in consideration of water dissolution stability, prevention of water evaporation and drying, and the like. 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 Alcoholic solvents such as -1-butin-3-ol, ethylene glycol monomethyl ether acetate and other higher alcohols, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, 3-methoxybutanol, 3-methoxy-3-methylbutanol Glycol ether-based solvents such as, etc. may be mentioned. These may be used alone or in admixture of two or more.

Further, as the water-soluble solvent, it is preferable to use a water-soluble solvent having an SP value different from the SP value of the surfactant having the acetylene bond in the structure and the silicone-based surfactant. This is because if the SP value of the water-soluble solvent and the SP value of the silicone-based surfactant are too close, they will be stabilized in the dissolved state, so that it tends to be difficult to quickly arrange the activator molecules on the gas-liquid interface. It is in. Therefore, if a water-soluble solvent having an SP value different from the SP value of the silicone-based surfactant is used, the activator molecules can be easily arranged at the gas-liquid interface and stability in the ink can be obtained. ,preferable. Therefore, considering the stability in the ink, the difference between the SP value of the silicone-based surfactant and the SP value of the water-soluble solvent is preferably 1 or more, and more considering it, 3 or more. It is preferable to have.

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., and 7 in consideration of ink leakage. It is preferably 0.0 to 20.0 mass or less.

In addition, it is preferable to use a phosphoric acid ester-based surfactant and a fatty acid in order to improve the lubricity, smooth the rotation of the ball, suppress the wear of the ball seat, and improve the writing quality. .. In particular, it is preferable to use a phosphoric acid ester-based surfactant having a phosphoric acid group. This is because the phosphoric acid group adsorbs the metal to further improve the lubricity, and it is easy to suppress the wear of the ball seat and improve the writing quality. Examples of the type of the phosphoric acid ester-based surfactant include styrene phenol-based, nonylphenol-based, lauryl alcohol-based, tridecyl alcohol-based, octylphenol-based, and hexanol-based. Among these, it is preferable to use a phosphoric acid ester-based surfactant that does not have a phenyl skeleton because having a phenyl skeleton tends to affect the lubricity due to steric hindrance. Considering more lubricity, lauryl alcohol-based and tridecyl alcohol-based phosphate ester-based surfactants are preferable, and these may be used alone or in combination of two or more. In particular, by using the organic resin particles in combination with the surfactant or silicone-based surfactant having the acetylene bond in the structure, the lubricity is further improved, and the writing quality and the wear suppression of the ball seat are easily improved. It is more effective because it is possible.

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

Further, in the ink composition of the present invention, it is preferable to use dextrin in order to suppress ink leakage.
By using dextrin, a film is formed when the ink on the pen tip dries, so ink leakage from the gap between the ball and the inner wall of the tip of the tip can be suppressed, or the pen tip can be dried up. This is because it is easy to obtain the effect of improving the performance. In particular, in the present invention, the combined use of the organic resin particles and dextrin is more effective in suppressing ink leakage.

The weight average molecular weight of the dextrin is more preferably 5000 to 120,000. When the weight average molecular weight of dextrin exceeds 120,000, the film formed on the pen tip is hard, and the handwriting tends to be easily blurred when writing out during dry-up. On the other hand, when the weight average molecular weight is less than 5,000, the moisture absorption property is high. This is because the height tends to be high, the film formed on the pen tip tends to be soft, and it tends to be difficult to sufficiently obtain the effect of suppressing ink leakage. Further, when the weight average molecular weight is smaller than 20000, the film tends to be thin, and therefore, the weight average molecular weight is most preferably 20000 to 120000.

The content of the dextrin in the ink composition is preferably 0.1 to 5% by mass with respect to the total amount of the ink composition. If it is less than 0.1% by mass, the effect of suppressing ink leakage and improving the dry-up performance of the pen tip tends not to be sufficiently obtained, and if it exceeds 5% by mass, it tends to be difficult to dissolve in the ink. Because. Considering the solubility in ink, it is preferably 0.1 to 3% by mass, and more considering the suppression of ink leakage and the improvement of dry-up performance, it is most preferably 1 to 3% by mass. preferable.

The ink viscosity modifier may include other than the alkaline swelling association type thickener. Examples of the ink viscosity adjusting agent include cross-linked acrylic acid polymers, xanthan gum, welan gum, succinoglycan, guar gum, locust bean gum, λ-carrageenan, cellulose derivatives, and Daiyutan gum. As the associated type thickeners other than the polysaccharides and the alkaline swelling associated type thickeners, the associated type thickening agents such as polyester type, polyether type, urethane-modified polyether type, and polyaminoplast type due to the associative hydrophobic group are used. Examples thereof include agents and nonionic association type thickeners, and these shear de-viscosity-imparting agents may be used alone or in combination of two or more.

Further, an additive can be contained if desired, specifically, a pH adjuster, an acrylic resin emulsion, a urethane resin emulsion, a styrene-butadiene resin emulsion, or the like, in order to improve the stability of the colorant over time. A fixing agent, an antibacterial agent such as 1,2-benzoisothiazolin-3-one, a moisturizing agent such as urea and sorbit, a rust preventive agent such as benzotriazole, and a chelating agent such as ethylenediamine tetraacetic acid can be added. These can be used alone or in combination of two or more.

<Aqueous ballpoint pen>
The ink composition of the present invention can be suitably used for a water-based ballpoint pen having a ballpoint pen tip that rotatably holds a ball at the tip of an ink containing cylinder.

In the present invention, it is conceivable to increase the ink consumption of the water-based ballpoint pen in consideration of obtaining smooth writing taste and good handwriting in color development. However, as the amount of ink consumed increases, the drying performance of the obtained handwriting deteriorates, and it becomes difficult to obtain a good handwriting.
Therefore, as a result of further diligent studies, the present inventor has determined the relationship between the specifications of the ballpoint pen tip and the ink consumption amount when the ink consumption amount per 100 m of the ballpoint pen is A (mg) and the ball diameter is B (mm). , 110 ≦ A / B ≦ 600, it was found that the handwriting drying property was excellent, the handwriting with good color development was obtained, and the smooth writing taste was obtained. Further, considering that the excess ink on the paper surface is suppressed and the handwriting drying property is improved by suppressing the bottom, it is preferable to set 120 ≦ A / B ≦ 500, and further, the above effect can be further enhanced. Considering this, it is preferable that 150 ≦ A / B ≦ 450.
The ink consumption per 100 m of the ballpoint pen is the amount of ink used for writing a 100 m writing line, and is subject to the conditions of 25 ° C., writing paper JIS P3201, writing angle 65 °, and writing load 100 g. Then, a spiral writing test was conducted for 25 minutes at a writing speed of 4 m / min using five test samples, and the average value of the amount of ink used (decrease) used at that time was calculated as the ink per 100 m. Defined as consumption.
The ball diameter is not particularly limited, but a ball having a diameter of about 0.1 to 2.0 mm is used.

Therefore, the ink composition of the present invention containing the silicone surfactant has 110 ≦ A / B ≦ 600 when the ink consumption per 100 m is A (mg) and the ball diameter is B (mm). In the water-based ballpoint pen, which is related to the above, it is possible to obtain a smooth writing taste at the same time as having excellent handwriting drying performance.

Further, in the water-based ballpoint pen of the present invention, the arithmetic mean roughness (Ra) of the surface of the ball is preferably 0.1 to 5 nm. When the arithmetic mean roughness (Ra) of the surface of the ball is 0.1 nm or more, the ink is sufficiently applied to the surface of the ball, and a handwriting with good color development can be obtained. When it is 5 nm or less, it is possible to prevent the writing quality from being deteriorated due to the unevenness of the surface of the ball and the rotational resistance between the ball and the ball seat from being increased to be deteriorated.
Further, the ink composition containing the surfactant having an acetylene bond in the structure or the silicone-based surfactant is placed on the surface of a ball whose surface arithmetic mean roughness (Ra) is within the above numerical range. Since it is easy to apply and the ink is evenly applied, it is possible to transfer an appropriate amount of ink composition to the paper surface. Therefore, while maintaining sufficient color development, it is difficult for more ink composition than necessary to be transferred to the paper surface, so that handwriting drying property is improved.
Further, in consideration of obtaining handwriting dryness and smooth and good writing quality, the arithmetic mean roughness (Ra) of the surface of the ball is preferably 0.5 to 3 nm.
The above arithmetic average roughness (Ra) can be measured by a surface roughness measuring instrument (manufactured by Seiko Epson, model name SPI3800N), and the reference length is taken in the direction of the average line from the measured roughness curve. It is the average value obtained by summing up the absolute values of the deviations from the average line of the extracted portion to the measurement curve.

Further, the amount of movement (clearance) of the ball of the ballpoint pen tip of the water-based ballpoint pen of the present invention in the vertical axis direction is preferably 20 to 45 μm. This is because if the amount of movement (clearance) is within the above numerical range, an appropriate amount of the ink composition is transferred to the paper surface at regular intervals to suppress the blurring, suppress the excess ink on the paper surface, and handwrite. It is easy to improve the drying property, and in particular, it is more effective to use a surfactant having the acetylene bond in the structure or a silicone-based surfactant because the handwriting drying property is easily improved. Further, if the movement amount (clearance) is within the above numerical range, the relationship between the ink consumption amount and the ball diameter when the ink consumption amount per 100 m is A (mg) and the ball diameter is B (mm) is determined. It is easy to set 110 ≦ A / B ≦ 600, it has excellent handwriting drying property, and it is easy to obtain a good handwriting without rubbing and smearing the paper surface or handwriting. Considering the above effects and writing taste, it is preferably 30 to 45 μm, and further considering it, it is preferably 30 to 40 μm.
The amount of movement (clearance) of the ball of the ballpoint pen tip in the vertical axis direction indicates the distance that the ball can move in the vertical direction of the ballpoint pen tip body.

<Manufacturing method of ink composition>
The ink composition according to the present invention can be produced by any conventionally known method. Specifically, each of the above components can be blended in a required amount and mixed with various stirrers such as a propeller stirrer, a homodisper, or a homomixer, or various dispersers such as a bead mill, and the like can be produced.

Next, the present invention will be described with reference to examples.
Example 1
Pigment dispersion (pH value 9 of carbon black, 10% by mass of carbon black aqueous dispersion, primary average particle diameter 17 nm)) 20.0 parts by mass
64.1 parts by mass of water
Polyhydric alcohol (ethylene glycol: SP value 14) 10.0 parts by mass
Acetylene glycol-based surfactant (HLB value 8, number of moles of ethylene oxide (EO) added: 2, number of moles of propylene oxide (PO) added: 2) 0.3 parts by mass
Organic resin particles (low density polyethylene dispersion, average particle diameter 6 μm, pH value 9, solid content 40%) 0.5 parts by mass
Dextrin (weight average molecular weight: 100,000) 1.0 part by mass
pH adjuster (triethanolamine) 2.0 parts by mass
Lubricant (phosphate ester-based surfactant) 1.0 part by mass
Rust inhibitor (benzotriazole) 0.5 parts by mass
Shear thinning agent (alkaline swelling association type thickener) 0.6 parts by mass

A base ink was prepared by heating and stirring a pigment dispersion, water, a polyhydric alcohol, an acetylene glycol-based surfactant, an organic resin particle, a dextrin, a pH adjuster, a lubricant, and a rust preventive with a magnetic stirrer.

Then, while heating the base ink produced above, a shear thinning agent is added, and the ink composition for a water-based ballpoint pen according to Example 1 is sufficiently mixed and stirred using a homogenizer stirrer until a uniform state is obtained. Got
The ink viscosity of Example 1 was measured using a DV-II viscometer (CPE-42 rotor) manufactured by Brookfield Co., Ltd. in an environment of 20 ° C. and a shear rate of 1.92 sec ^-1 (rotation speed 0.5 rpm). When the ink viscosity was measured under the conditions, it was 530 mPa · s.
The pH value of Example 1 was measured at 20 ° C. using an IM-40S type pH meter (manufactured by DKK-TOA CORPORATION), and the pH value was 8.7.

Examples 2-19
The ink compositions for water-based ballpoint pens of Examples 2 to 19 were obtained in the same procedure as in Example 1 except that the ink composition was changed as shown in the table. The table shows the ink formulation and evaluation results.

Test and Evaluation A ballpoint pen tip (ball diameter: 0.7 mm, ball) in which the ink composition for a water-based ballpoint pen produced in Examples 1 to 19 and Comparative Examples 1 to 4 is rotatably held at the tip of an ink storage cylinder. A gel ink ballpoint pen (trade name) manufactured by Pilot Corporation, which is filled with a refill (1.0 g) filled in an ink storage cylinder (made of polypropylene) provided with an arithmetic mean roughness (Ra): 1 nm) on the surface via a chip holder. : Attached to G-2), the following tests and evaluations were performed. The amount of movement (clearance) of the ball of the ballpoint pen tip in the vertical direction is as shown in the table. For the handwriting drying performance test and the evaluation of the writing taste, JIS P3201 writing paper A was used as the writing test paper, and the evaluation was performed by the following test method.
Further, when a spiral writing test was performed using the ink composition for a water-based ballpoint pen of Example 1 as a water-based ballpoint pen, the ink consumption of the ballpoint pen per 100 m was A (mg), and the ball diameter was B (mm). , A = 200 (mg), the ball diameter was B = 0.7 (mm), and A / B = 286.

Handwriting drying performance test After writing on the paper, the handwriting was scraped with tissue paper every elapsed time, and the handwriting drying performance was evaluated according to the following criteria.
Writing is less than 2 seconds and the handwriting is dry ... ◎◎
Writing 2 seconds or more and less than 5 seconds, the handwriting is dry ... ◎
Writing in 5 seconds or more and less than 10 seconds, the handwriting is dry ... ○
Writing in 10 seconds or more and less than 20 seconds, and the handwriting is dry ... △
The handwriting did not dry even after 20 seconds of writing ... ×

Ink leakage test: A weight of 40 g is attached to the barrel of the water-based ballpoint pen for testing, the ballpoint pen tip is ejected and turned downward, and the ball of the ballpoint pen tip is kept in contact with the bottom of the ballpoint pen display case. The ink was left in an environment of ℃ and 65% RH for one day, and the amount of ink leaked from the tip of the ballpoint pen tip was measured.
Ink leakage is less than 5 mg ... ◎
Ink leakage amount of 5 to 15 mg ... ○
Ink leakage amount exceeds 15 mg and less than 30 mg ... △
Ink leakage amount of 30 mg or more ・ ・ ・ ×

Writing taste: A handwritten sensory test was conducted and evaluated.
The writing taste was extremely smooth ... ◎
It was a smooth writing taste ... ○
I felt a little heavy writing, but it was a level that was not a problem in practice ... △
The writing taste was heavy and slippery ... ×

From the results in the table, in Examples 1 to 19, good levels of performance were obtained in the handwriting drying performance test, the ink leakage test, and the writing quality.

From the results in the table, in Comparative Example 1, since no surfactant or silicone-based surfactant having an acetylene bond in the structure was used, the level was inferior in the handwriting drying performance test.

In Comparative Examples 2 and 3, since the surfactant used was a surfactant other than the surfactant having an acetylene bond in the structure and the silicone-based surfactant, the level was inferior in the handwriting drying performance test.

In Comparative Example 4, since a thickener other than the alkaline swelling association type thickener was used, the level was inferior in the handwriting drying performance test.

Generally, in a ballpoint pen tip of a water-based gel ballpoint pen, in order to suppress ink leakage, a ball rotatably held at the tip of the ballpoint pen tip is held directly at the tip edge of the tip by a repulsive member such as a coil spring or via a pressing body. It is preferable to provide a valve mechanism that presses against the inner wall and gives 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 to allow ink to flow out, and closes even a minute gap at the tip of the tip when not in use.

The present invention can be used as a water-based ballpoint pen, and more specifically, can be widely used as a cap-type, haunting-type, or the like water-based ballpoint pen.

Claims (9)

An ink composition for an aqueous ball pen containing water, a colorant, a surfactant, and an alkaline swelling-associating thickener, wherein the surfactant is a silicone-based surfactant and the silicone-based surfactant. An ink composition for a water-based ball pen, characterized in that the weight average molecular weight is 500 to 2000. An ink composition for an aqueous ball pen containing water, a colorant, a surfactant, and an alkaline swelling-associating thickener, wherein the surfactant has an acetylene bond in its structure, and the acetylene is described above. An ink composition for an aqueous ball pen, wherein the surfactant having a bond in the structure has an ethylene oxide addition molar number of 8 or less and an HLB value of 3 to 14. The ink composition for a water-based ballpoint pen according to claim 1 or 2 , wherein the ink composition for a water-based ballpoint pen contains a phosphoric acid ester-based surfactant. The ink composition for a water-based ballpoint pen according to any one of claims 1 to 3 , wherein the colorant is a pigment. The ink composition for an aqueous ballpoint pen according to any one of claims 2 to 4 , wherein the surfactant having an acetylene bond in the structure is added with propylene oxide. The ink composition for a water-based ballpoint pen according to any one of claims 1 to 5, wherein the ink composition for a water-based ballpoint pen contains dextrin. A ballpoint pen tip that rotatably holds a ball is held at the tip of an ink containing cylinder, and the ink composition for a water-based ballpoint pen according to any one of claims 1 to 6 is accommodated in the ink containing cylinder. A water-based ballpoint pen characterized by becoming. The water-based ballpoint pen according to claim 7 , wherein the amount of movement of the ball of the ballpoint pen tip of the water-based ballpoint pen in the vertical axis direction is 20 to 45 μm. The invention according to claim 7 or 8, wherein when the ink consumption per 100 m of the water-based ballpoint pen is A (mg) and the ball diameter is B (mm), 110 ≦ A / B ≦ 600. Water-based ballpoint pen.