JP2018109113A - Aqueous ballpoint ink composition and aqueous ballpoint prepared therewith - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an aqueous ballpoint ink composition that improves handwriting dryability through improved permeability to a paper surface and improves a writing feel through improved lubricity, and an aqueous ballpoint prepared therewith.SOLUTION: An aqueous ballpoint ink composition contains water, a colorant, and a silicone-based surfactant. The silicone surfactant is at least one selected from general formulae (1), (2), (3). There is also provided an aqueous ballpoint prepared therewith.SELECTED DRAWING: None

Description

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

The ink composition for water-based ballpoint pens is an ink composition in which the main solvent is water. For this reason, if the pen tip is left in the atmosphere for a while, the water that is the main solvent evaporates from the pen tip, the ink viscosity becomes higher, the handwriting becomes blurred, and the evaporation of moisture proceeds. Phenomenon has been confirmed to dry and solidify, making it impossible to write due to clogging of the ink flow path of the writing instrument. In particular, when it is used for a retractable ballpoint pen, this phenomenon is remarkably likely to occur because the pen tip is always exposed to the atmosphere. Therefore, in order to suppress moisture evaporation in the ink composition, it is a common practice to add a polyhydric alcohol solvent such as glycerin or ethylene glycol as a humectant. However, although there is a tendency to suppress water evaporation of the ink, the resulting handwriting requires time to dry completely, so if you touch the handwriting that is not dry, the writing surface will become dirty, There is a problem that the handwriting itself becomes dirty.
In order to solve these problems, 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 dioctylsulfosuccinate, and Patent Document 3 discloses an ink composition containing a fluorine-based surfactant. Many ink compositions have been proposed in which the surface tension of the composition is lowered to improve the permeability to paper.

  However, although the ink composition of Patent Document 1 improves the drying property of handwriting, there is a problem in stability over time due to the unusual odor of alcohol solvents and high volatility. Moreover, although the ink composition of patent document 2 tends to improve the dryness of a handwriting, it is hard to say that it is sufficient, and it was difficult to obtain a good handwriting.

  Moreover, when the ink composition as disclosed in Patent Documents 2 and 3 is used in a ballpoint pen, although penetrability into the paper surface is improved to some extent, further improvement in handwriting dryness and improvement in lubricity have been desired. Furthermore, the wettability with respect to a ball-point pen tip also increased, ink was likely to leak from the pen tip, and the water-based ball-point pen ink composition was not sufficiently satisfactory.

  In recent years, ballpoint pens are often arranged in a display case. In the case of a cap-off ballpoint pen such as a retractable ballpoint pen, if the ballpoint pen tip is projected and returned to the display case, the ball and tip A gap is formed between the inner wall of the tip, ink drops from the gap, ink leakage occurs, the display case is soiled, and other ballpoint pens in the case are prone to soiling, which is improved. It is hoped at the same time.

JP 2000-319570 A JP 2005-238672 A JP 2004-224892 A

  An object of the present invention is to obtain an aqueous ballpoint pen ink composition that improves the handwriting drying property and further improves the writing quality, and an aqueous ballpoint pen using the same.

２．前記シリコーン系界面活性剤の重量平均分子量が５００〜３０００であることを特徴とする第１項に記載の水性ボールペン用インキ組成物。
３．前記着色剤が顔料であることを特徴とする第１項にまたは第２項に記載の水性ボールペン用インキ組成物。
４．前記水性ボールペン用インキ組成物に有機樹脂粒子を含んでなることを特徴とする第１項ないし第３項のいずれか１項に記載の水性ボールペン用インキ組成物。
５．前記有機樹脂粒子がオレフィン系樹脂であることを特徴とする第４項に記載の水性ボールペン用インキ組成物。
６．前記有機樹脂粒子がオレフィン系樹脂であることを特徴とする第４項に記載の水性ボールペン用インキ組成物。」とする。
In order to solve the above problems, the present invention
“1. An aqueous ballpoint pen ink composition comprising water, a colorant, and a silicone surfactant, wherein the silicone surfactant is represented by the following general formulas (Chemical Formula 1), (Chemical Formula 2), (Chemical Formula 2) An ink composition for water-based ballpoint pens, wherein one or more are selected from 3).

2. The water-based ballpoint pen ink composition according to item 1, wherein the silicone-based surfactant has a weight average molecular weight of 500 to 3,000.
3. 3. The water-based ballpoint pen ink composition according to item 1 or 2, wherein the colorant is a pigment.
4). 4. The water-based ballpoint pen ink composition according to any one of items 1 to 3, wherein the water-based ballpoint pen ink composition comprises organic resin particles.
5. The ink composition for water-based ballpoint pens according to item 4, wherein the organic resin particles are an olefin resin.
6). The ink composition for water-based ballpoint pens according to item 4, wherein the organic resin particles are an olefin resin. "

  The present invention provides a water-based ballpoint pen ink composition that improves penetrability to paper by improving penetrability and further improves lubricity, and an aqueous ballpoint pen using the same. I was able to get it.

The feature of the present invention is that one or more silicone surfactants represented by the structural formulas of the following general formulas (Chemical Formula 1), (Chemical Formula 2), and (Chemical Formula 3) are selected as specific silicone surfactants. An ink composition for water-based ballpoint pens and a water-based ballpoint pen using the same.

<Silicone surfactant>
As the silicone-based surfactant used in the present invention, one or more structural formulas of the general formulas (Chemical Formula 1), (Chemical Formula 2), and (Chemical Formula 3) are selected and used, so that the ink on the written paper surface can be used. By improving the penetrability, the handwriting drying property can be improved. Furthermore, the writing quality can be improved by improving the lubricity.

Among the silicone surfactants, the general formulas (Chemical Formula 1) and (Chemical Formula 2) are preferably used. This is because the ethylene oxide group or propylene oxide group in the structure of the silicone surfactant is hydrophilic. This is to make the balance of hydrophobicity suitable. Here, if the hydrophilicity of the silicone-based surfactant is too high, the solubility in the ink becomes too high, and it is difficult for the surfactant molecules to be quickly aligned with the gas-liquid interface, and the permeability tends to be difficult to improve. If the silicone-based surfactant is too hydrophobic, the solubility in the ink becomes too low, and not only the permeability is hardly improved, but also the stability to the ink tends to be poor due to separation or the like.
Silicone surfactants of general formulas (Chemical Formula 1) and (Chemical Formula 2) have an ethylene oxide group or a propylene oxide group in the structure, so that the balance between hydrophilicity and hydrophobicity is suitable, so that they are stable in ink. However, since the activator molecules are easily arranged at the gas-liquid interface quickly, the surface tension of the ink is quickly controlled at the time of writing, and the permeability is improved. Ink is easy to obtain. From the viewpoint of handwriting drying, it is preferable to use the general formula (Formula 1).

  Among the silicone surfactants, the weight average molecular weight is preferably 500 to 3,000. This is because when the weight average molecular weight of the surfactant described above is 3000, the silicone surfactant molecules tend to be too large and the alignment to the gas-liquid interface tends to be delayed. Therefore, the handwriting drying property 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, whereby the surfactant molecules tend to be quickly arranged on the gas-liquid interface, and the handwriting drying property Easy to improve. Further, if the weight average molecular weight is less than 500, it is difficult to obtain desired handwriting drying properties. In view of 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 preferred. In addition, with regard to x and y in the general formulas (Chemical Formula 1), (Chemical Formula 2), and (Chemical Formula 3), the weight average molecular weight is not increased so that the handwriting dryness can be improved more easily. The range of x and y = 0 to 1 is preferable.

  With regard to the solubility parameter (hereinafter referred to as SP value) of the silicone-based surfactant, it is preferable that the SP value is 8 to 13 in consideration of handwriting dryness, and if more considered, the SP value is 9 to 12. It is preferable that the SP value is 10 to 11 in particular. The SP value of water, which is the main component of the solvent, is 23.4, and if the SP value of the silicone surfactant is too close, the solution is stabilized in a dissolved state, so that the arrangement of the activator molecules at the gas-liquid interface is quick. It tends to be difficult to achieve. When the SP value is in the above-mentioned range, it is preferable because the activator molecules are easily arranged at the gas-liquid interface and stability in the ink is also obtained.

  Specific examples of the silicone surfactant include Silface series (manufactured by Nissin Chemical Industry Co., Ltd.), BYK series (manufactured by Big Chemie Co., Ltd.), Silos Spread series, and Cotosil series (all of which are momentary performances). Materials Co., Ltd.). You may use these individually or in mixture of 2 or more types.

  Moreover, about content of the said silicone type surfactant, 0.01-3.0 mass% is more preferable with respect to the ink composition whole quantity. This is because if the content of the silicone surfactant is less than 0.01% by mass, it is difficult to obtain the desired handwriting drying property. If the content exceeds 3.0% by mass, the ink aging stability is affected. This is because it is easy. Furthermore, considering more, 0.05 to 2.0 mass% is preferable, and 0.1 to 1.5 mass% is particularly preferable.

<Colorant>
The colorant used in the present invention is not particularly limited, and pigments, dyes and the like used in water-based ballpoint pen ink compositions can be used.

Examples of pigments include inorganic, organic, and processed pigments. Specifically, carbon black, aniline black, ultramarine, yellow lead, titanium oxide, iron oxide, phthalocyanine, azo, quinacridone, quinophthalone, selenium , Triphenylmethane, perinone, perylene, dioxazine, microcapsules, aluminum pigments, pearl pigments, fluorescent pigments, phosphorescent pigments, and complementary color pigments. As the dye, direct dyes, acid dyes, basic dyes, metal-containing dyes, various salt-forming dyes, and the like can be used. These pigments and dyes may be used alone or in combination of two or more.
Dyes are in a dissolved state in ink, whereas pigments are dispersed in an insoluble state in ink. It is difficult to improve. However, in the present invention, it is preferable to use a silicone-based surfactant represented by the general formulas (Chemical Formula 1), (Chemical Formula 2), or (Chemical Formula 3) because it can be suitably used even when a pigment is used. In addition, it is preferable to use a pigment in view of obtaining excellent color development with excellent water resistance and light resistance, and considering the effect of suppressing ink leakage due to insolubility of the pigment.

Among these colorants, it is preferable to use a pigment having a primary average particle diameter of 1 to 100 nm. This is the above range, when the silicone-based surfactant penetrates into the paper surface, it is easy to penetrate into the paper surface without catching the pigment together with the silicone-based surfactant, Since it is easy to improve the handwriting drying property after writing, it becomes easier to obtain a synergistic effect with the silicone surfactant, which is effective. Considering more, it is preferable to use a pigment having a primary average particle diameter of 5 to 40 nm. Considering more, it is preferable to use a pigment having a thickness of 10 to 30 nm, and most preferable to use a pigment having a diameter of 10 to 20 nm. preferable.
The average particle size of the pigment is the particle size at 50% volume cumulative particle size distribution measured by a laser diffraction method using a laser diffraction particle size distribution analyzer (trade name “Microtrac HRA9320-X100”, Nikkiso Co., Ltd.). (D50).

In particular, when carbon black is used, it is preferable to use a carbon black 10 mass% aqueous dispersion having a pH value in the range of 5-10. This is because when the pH value is less than 5, since there are many acidic groups on the surface of the carbon black, it shows hydrophilicity and the dispersibility in water becomes high. In order to improve the handwriting drying property, it is preferable that the fixing property of a certain level or more is obtained with respect to the paper surface after writing, which improves the scratch resistance and improves the handwriting drying property. If it is less than 5, if the hydrophilicity is too high, it tends to take time until the fixability is obtained due to the influence of the moisture of the ink transferred onto the paper surface, and the handwriting dryness tends to be poor. On the other hand, when the pH value is 5 or more, fixing to the paper surface can be obtained in a relatively short time due to a synergistic effect with the surfactant, improving the scratch resistance and improving the handwriting drying property. It is preferable that the value is 5 or more. On the other hand, if the pH value exceeds 10, strong basic groups on the surface of the carbon black may affect the balls of the metal material or may impair the orientation of the surfactant, and the writing quality tends to be inferior. It is preferable that the pH value is 10 or more. Therefore, when the pH value of the carbon black 10 mass% aqueous dispersion is in the range of 5 to 10, the fixability is improved, the handwriting dryness is improved, and the effect of the surfactant is not hindered. It is preferable because the receiving seat is not worn and the writing is smooth. Considering more, it is preferable that the pH value of the carbon black 10 mass% aqueous dispersion is in the range of 6-10.
As the pH value of the 10% by mass aqueous dispersion of carbon black, a value obtained by measuring the aqueous carbon black dispersion when the concentration of carbon black is 10% by mass is used.
The aqueous dispersion of 10% by mass of carbon black can be prepared by dispersing carbon black in water while stirring or by diluting a commercially available carbon black aqueous dispersion.

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

  As for content of a coloring agent, 1.0-20.0 mass% is preferable with respect to the ink composition whole quantity. If it is less than 1.0% by mass, it tends to be difficult to obtain a handwriting with good color development. If it exceeds 20.0% by mass, the solubility in ink and the stability over time due to aggregation tend to be affected. In view of this tendency, 3.0 to 10.0% by mass is most preferable.

<Water>
There is no restriction | limiting in particular as water, For example, ion-exchange water, ultrafiltration water, or distilled water can be used.

<Organic resin particles>
The ink composition of the present invention preferably uses organic resin particles.
When the ink composition of the present invention is selected from one or more silicone surfactants represented by structural formulas such as (Chemical Formula 1), (Chemical Formula 2), and (Chemical Formula 3), the ink composition Since the wettability with respect to the paper surface is improved, the permeability to paper is improved, and good handwriting dryness and good writing quality can be obtained. On the other hand, the wettability with the ball and the ballpoint pen tip is increased, and the ink may leak out from the gap between the ball and the inner wall at the tip of the ballpoint pen tip. In particular, when the ink composition of the present invention is used for a ballpoint pen whose pen tip such as a retractable ballpoint pen is exposed and can always be in a cap-off state, the possibility of ink leakage is very high. The problem of ink leakage can be prevented by increasing the ink viscosity of the ink composition, but in this case, the time until the resulting handwriting is completely dried increases, and the handwriting drying performance is poor. Furthermore, the ink consumption 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 dryness and good handwriting can be obtained. Therefore, in the present invention, it is particularly preferable to use organic resin particles. The organic resin particles cause physical obstacles in the gap between the ball and the inner wall of the tip of the ballpoint pen tip, and can suppress ink leakage, but the organic resin particles have a hardness higher than that of inorganic particles. Since the particles are partly deformed and are in close contact with each other and form a weak aggregate structure, the effect of suppressing ink leakage is high.
Further, the organic resin particles not only suppress ink leakage as described above, but also can enter between the ball and the ball seat and make it difficult to make direct contact. The wear of the seat can be suppressed and the writing quality can be improved.

For organic resin particles, olefin resin particles such as polyethylene resin and polypropylene resin, and organic resin particles having hydrogen bonding 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.
In addition, recently, in the case of a cap-off ballpoint pen such as a retractable ballpoint pen, when the ballpoint pen tip is returned to the display case with the protruding tip, the ballpoint pen on which test writing has been made is returned to the display case. As the process repeats, many ballpoint pens may be stacked on the ballpoint pen that was returned to the beginning. As a result, the ball at the tip of the ballpoint pen tip moves in the vertical axis direction due to the weight of the plurality of ballpoint pens stacked, and a gap may be created between the ball and the inner wall at the tip end of the tip, causing ink leakage. Assuming that the occurrence of ink leakage as described above is suppressed, it is preferable to use olefin-based resin particles that have a remarkably high ink leakage suppression effect.

  This is because the olefin resin particles are optimized so that they do not cause problems such as insufficient ink volume while containing ink and preventing ink leakage due to its nonpolar nature. Therefore, it is presumed that an ink leakage suppressing effect can be obtained. Furthermore, since the olefin resin particles have a high melting temperature, they tend to exist stably even in a high temperature environment, and when they are in a high pressure environment, they are easy to deform and difficult to modify. Since it is stable even if it is sandwiched between the ball and the ball seat, a cushioning effect is obtained, writing quality is improved, and wear suppression of the ball seat is obtained, so it can be used more suitably. By using in combination with the silicone surfactant, it is possible to further improve the lubricity.

  Examples of the material for the olefin resin particles include polyolefins such as polyethylene, polypropylene, and polybutene, and mixtures thereof. Among these, it is preferable to use polyethylene in consideration of ink leakage suppression and improvement in writing quality. Specifically, low density polyethylene, high density polyethylene, low molecular polyethylene, modified polyethylene, modified high density polyethylene are preferable. Etc. Among them, low density polyethylene, low molecular weight polyethylene, and modified polyethylene are preferable in consideration of the ink leakage suppression effect. Particularly, low density polyethylene has a lower melting point than other types of polyethylene and has a soft property, so that the polyethylene particles adhere to each other. Low density polyethylene is preferable because it is easy to form, and it is difficult to cause gaps between particles and ink does not leak. Furthermore, since low density polyethylene is soft, a cushioning effect between the ball and the ball seat can be easily obtained. Can be suitably used because the wear of the ball seat is suppressed. The olefin resin particles may contain a material other than polyolefin as required.

  Based on the above, the ink composition of the present invention comprising one or more selected from the structural formulas of the general formulas (Chemical Formula 1), (Chemical Formula 2), and (Chemical Formula 3) as the silicone surfactant is used. By containing the organic resin particles, it is possible to effectively prevent ink leakage from the pen tip while maintaining excellent handwriting dryness, and the writing quality can be further improved.

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

  Moreover, when using the said olefin resin particle, it is preferable to use the olefin resin particle dispersion previously disperse | distributed to water etc., However, As for the pH value of an olefin resin particle dispersion, 7-11 are preferable. This is because the dispersion stability of the olefin-based resin particle dispersion and the stability with respect to ink components such as a colorant and a surfactant are easily improved. Considering more, a pH value of 7 to 10 is more preferable.

  Moreover, about content of the said organic resin particle, 0.01-10.0 mass% is more preferable with respect to the ink composition whole quantity. This is because it is difficult to suppress ink leakage when the content of the organic resin particles is less than 0.01% by mass, and when the content exceeds 10.0% by mass, the agglomeration structure tends to become strong, and writing quality and dry-up performance are improved. It is because it is easy to be affected. Furthermore, considering more, 0.05 to 5.0 mass% is preferable, 0.1 to 3.0 mass% is particularly preferable, and most preferably 0.5 to 2.0 mass% is preferable.

  In consideration of water dissolution stability, prevention of water evaporation and drying, it is preferable to use a water-soluble solvent. Polyhydric alcohol solvents such as ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, polyethylene glycol, glycerin, methanol, ethanol, 1-propanol, 2-propanol, isopropanol, isobutanol, t-butanol, allyl alcohol, 3-methyl -1-butyn-3-ol, alcohol solvents such as ethylene glycol monomethyl ether acetate and other higher alcohols, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, 3-methoxybutanol, 3-methoxy-3-methylbutanol And glycol ether solvents such as You may use these individually or in mixture of 2 or more types.

  Furthermore, for the water-soluble solvent, it is preferable to use a water-soluble solvent having an SP value different from the SP value of the silicone surfactant. This is because if the SP value of the water-soluble solvent and the SP value of the silicone surfactant are too close, the solution is stabilized in a dissolved state, and therefore the arrangement of the activator molecules at the gas-liquid interface tends to be difficult to be achieved quickly. 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 readily arranged at the gas-liquid interface, and stability in ink can be obtained. ,preferable. In view of the stability in ink, the difference between the SP value of the silicone surfactant and the SP value of the water-soluble solvent is preferably 1 or more, and more preferably 3 or more. Preferably there is.

  Further, 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, and the like. 0.0-20.0 mass or less is preferable.

  In addition, by using the lubricant, the rotation of the ball becomes smooth and the lubricity is improved. As the lubricant, it is preferable to use a phosphate ester-based surfactant and a fatty acid in order to easily suppress the wear of the ball seat and improve the writing quality. In particular, it is preferable to use a phosphate ester-based surfactant having a phosphate group. This is because the phosphate group is adsorbed to the metal, thereby improving the lubricity and making it easier to suppress wear of the ball seat and improve the writing quality. Examples of the phosphate ester surfactant include styrenated phenols, nonylphenols, lauryl alcohols, tridecyl alcohols, octylphenols, hexanols, and the like. Among these, since having a phenyl skeleton tends to affect lubricity due to steric hindrance, it is preferable to use a phosphate ester-based surfactant having no phenyl skeleton. In consideration of lubricity, lauryl alcohol and tridecyl alcohol phosphate surfactants are preferable. These may be used alone or in combination of two or more. In particular, by using the silicone surfactant and the organic resin particles in combination, it is possible to improve lubricity more easily, and to improve the writing taste and wear suppression of the ball seat, which is more effective. .

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

The ink composition of the present invention preferably uses dextrin to suppress ink leakage.
This is because dextrin is used to form a film when the ink at the nib dries, thus preventing ink leakage from the gap between the ball and the inner wall of the tip of the tip, or drying up the nib This is because the effect of improving the performance is easily obtained. 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 there is a tendency that handwriting tends to be blurred in writing at the time of dry-up. On the other hand, when the weight average molecular weight is less than 5000, hygroscopicity This is because the film tends to be high, the film formed on the pen tip tends to be soft, and the effect of suppressing ink leakage tends to be difficult to obtain sufficiently. Furthermore, when the weight average molecular weight is smaller than 20000, the film tends to be thin, and the weight average molecular weight is most preferably 20000 to 120,000.

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

The water-based ink composition of the present invention preferably comprises an ink viscosity modifier. As the ink viscosity adjusting agent, a shear thinning agent is preferably used.
Examples of the shear thinning agent include cross-linked acrylic polymers, polysaccharides such as xanthan gum, welan gum, succinoglycan, guar gum, locust bean gum, λ-carrageenan, cellulose derivatives, and diutan gum, and associative thickening. A sticky agent is mentioned. The associative thickener may be an associative thickener such as a polyester, polyether, urethane-modified polyether, polyaminoplast, or the like, an alkali-swelling associative thickener, Nonionic associative thickeners and the like can be mentioned. Among these, polysaccharides and associative thickeners are preferably used in consideration of ink aging stability. These shear thinning agents may be used alone or in combination of two or more.

  Further, the associative thickener is preferable because an effect of easily improving handwriting drying property and pigment dispersibility is obtained. The associative thickener has a hydrophilic group as a skeleton and has a hydrophobic group in a side chain or a terminal. When a pigment is used, the hydrophobic group of the associative thickener is added to the pigment. Adsorption forms a mutual structure of pigment and associative thickener in the ink. When writing, the above-mentioned silicone-based surfactant allows the pigment and the associative thickener that have formed the mutual structure to quickly penetrate into the paper surface, and the mutual structure is partially entangled with the paper fiber in a three-dimensional manner. Estimated to settle. Since each component in the ink functions as a penetrating agent and a fixing agent, and improves the abrasion resistance, the handwriting drying property is easily improved. Further, associative thickeners are preferably used because hydrophobic groups are adsorbed on the pigment and function as a dispersant to easily improve pigment dispersibility. In consideration of improving handwriting drying property and pigment dispersibility, it is preferable to use an alkali swelling associative thickener.

  Further, in the case where a pigment and organic resin particles are used as the associative thickener, a high-density three-dimensional structure is formed by adsorbing the hydrophobic group of the associative thickener to the pigment and the organic resin particles. For this reason, even if the ink viscosity is low, an effect of suppressing ink leakage is easily obtained. Furthermore, considering the improvement of the effect, among the associative thickeners, it is preferable to use an alkali swelling associative thickener. This is because the alkali-swelling associative thickener has high ink viscosity expression efficiency among the associative thickeners, and when the pigment and the organic resin particles are used, the adsorptivity to the pigment and the organic resin particles is high. This is because it is easy to form a cross-linked structure and a high-density three-dimensional structure is formed, so that it is easy to improve ink leakage suppression.

  The alkali swelling associative thickener is a polymer of monomers or copolymers containing various polymerizable monomers having a carboxyl group such as acrylic acid, methacrylic acid, maleic acid, etc. as a mechanism showing alkali swelling property. Examples of the resin include a resin having a stable swellability for a long period of time because it can be expected to suppress ink leakage and further improve the pigment dispersibility and easily improve the ink aging stability. Among these, those composed of three types of monomers, vinyl acetate, methyl methacrylate, and methacrylic acid are particularly preferable.

  Moreover, as for content of the said ink viscosity modifier in an ink composition, 0.01-5 mass% is more preferable on the basis of the total mass of an ink composition. This is because if the content of the shear thinning agent is less than 0.01% by mass, the ink thickening effect is not sufficient, and it is difficult to suppress ink leakage, and if it exceeds 5% by mass, the ink viscosity increases. This is because it tends to affect the ball seat wear suppression, ink followability during writing, writing quality, and dry-up resistance. Furthermore, if it considers more, 0.1-2 mass% is preferable, Most preferably, you may be 0.1-1 mass%.

  Further, if desired, an additive can be contained. Specifically, in order to improve the temporal stability of the colorant, a pH adjuster, a fluorosurfactant, a surfactant having an acetylene bond, succinic acid Wetting agents such as surfactants, fixing agents such as acrylic resin emulsions, urethane resin emulsions, styrene-butadiene resin emulsions, antibacterial agents such as 1,2-benzisothiazolin-3-one, and moisturizing agents such as urea and sorbit Agents, rust preventives such as benzotriazole, and chelating agents such as ethylenediaminetetraacetic acid can be added. These can be used alone or in combination of two or more.

  Moreover, 7-11 are preferable as for pH of the water-based ink composition of this invention. This is because if the pH is within the above numerical range, each component in the ink composition can exist stably, and corrosion of the ball-point pen tip can be prevented. In the present invention, the pH value can be measured at 20 ° C., for example, with an IM-40S type pH meter (manufactured by Toa DKK Corporation).

<Water-based ballpoint pen>
The ink composition of the present invention can be suitably used for a water-based ballpoint pen having a ballpoint pen tip having a ball rotatably held 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 by further considering obtaining a smooth writing taste and good handwriting. However, when the ink consumption increases, the drying performance of the obtained handwriting decreases, and it becomes difficult to obtain good handwriting.
Therefore, as a result of further intensive studies, the present inventor has found that the relationship between the specifications of the ballpoint pen tip and the ink consumption is A (mg) when the ink consumption per 100 m of the ballpoint pen is B (mm) and the ball diameter is B (mm). 110 ≦ A / B ≦ 600, it was found that a handwriting with excellent handwriting dryness and good color development was obtained, and a smoother writing quality was obtained. In addition, it is preferable to satisfy 120 ≦ A / B ≦ 500 in view of improving handwriting drying property by suppressing excess ink on the paper surface by suppressing voids, and more preferably, the above effect, In consideration, it is preferable that 150 ≦ A / B ≦ 450.
The ink consumption per 100 m of the ballpoint pen is the amount of ink used to write a 100 m writing line, and the conditions are 25 ° C., writing paper JIS P3201, writing angle 65 °, and writing load 100 g. The spiral writing test was performed using 5 test samples for 25 minutes at a writing speed of 4 m / min, and the average value of the amount of ink used (decrease amount) used at that time was the ink per 100 m. It is defined as consumption.
The ball diameter is not particularly limited, but a ball of about 0.1 to 2.0 mm is used.

  Therefore, the ink composition of the present invention comprising the silicone surfactant has 110 ≦ A / B ≦ when the ink consumption per 100 m is A (mg) and the ball diameter is B (mm). In the water-based ballpoint pen having a relationship of 600, the handwriting drying performance is excellent and at the same time a smooth writing feel can be obtained.

In the aqueous ballpoint pen of the present invention, the arithmetic average roughness (Ra) of the ball surface is preferably 0.1 to 5 nm. When the arithmetic average roughness (Ra) of the surface of the ball is 0.1 nm or more, ink is sufficiently deposited on the surface of the ball, and a handwriting with good coloring can be obtained. If the thickness 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 writing resistance from being lowered due to an increase in rotational resistance between the ball and the ball seat.
In addition, the ink composition comprising the silicone surfactant has a surface arithmetic average roughness (Ra) that is easy to get on the surface of the ball within the above numerical range, and more uniformly, so that It is possible to transfer an appropriate amount of the ink composition. Therefore, while maintaining sufficient color developability, it is difficult to transfer an ink composition more than necessary onto the paper surface, so that handwriting dryness is improved.
Furthermore, in view of obtaining handwriting dryness and smooth writing quality, the arithmetic average roughness (Ra) of the surface of the ball is preferably 0.5 to 3 nm.
The arithmetic average roughness (Ra) can be measured with a surface roughness measuring instrument (manufactured by Seiko Epson, model name SPI3800N), and the reference length in the direction of the average line from the measured roughness curve. This is a value obtained by summing and averaging the absolute values of deviations from the average line of the extracted portion to the measurement curve.

Moreover, it is preferable that the movement amount (clearance) of the ball | bowl pen tip ball | bowl tip of the water-based ball-point pen of this invention is 20-45 micrometers. 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, thereby suppressing blur and reducing excess ink on the paper surface. It is easy to improve the drying property. In particular, it is more effective to use the silicone surfactant because the handwriting drying property is easily improved. Further, if the movement amount (clearance) is in the above numerical range, the relationship between the ink consumption and the ball diameter when the ink consumption per 100 m is A (mg) and the ball diameter is B (mm), It is easy to set 110 ≦ A / B ≦ 600, excellent handwriting drying property, and it is easy to obtain good handwriting without rubbing the paper surface or handwriting. In consideration of the above effects and writing quality, the thickness is preferably 30 to 45 μm, and further considered to be 30 to 40 μm.
The movement amount (clearance) 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.

<Method for producing ink composition>
The ink composition according to the present invention can be produced by any conventionally known method. Specifically, it can be produced by blending the necessary amounts of the above components and mixing them with various agitators such as propeller agitation, homodisper, or homomixer, and various dispersers such as a bead mill.

Next, an Example is shown and this invention is demonstrated.
Example 1
20.0 parts by mass of pigment dispersion (carbon black, pH value 9 of water dispersion of 10% by mass of carbon black, primary average particle diameter 17 nm)
64.1 parts by weight of water
Polyhydric alcohol (ethylene glycol: SP value 14) 10.0 parts by mass
Silicone surfactant (Chemical formula 1) 0.3 parts by mass
Organic resin particles (low density polyethylene dispersion, average particle size 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 surfactant) 1.0 part by mass
Rust preventive (benzotriazole) 0.5 parts by mass
Shear thinning agent (alkali swelling association type thickener) 0.6 parts by mass

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

Thereafter, while heating the base ink prepared above, a shear thinning agent was added, and the mixture was sufficiently mixed and stirred using a homogenizer stirrer until a uniform state was obtained. Got.
The ink viscosity of Example 1 was measured using a Brookfield DV-II viscometer (CPE-42 rotor) at a shear rate of 1.92 sec ⁻¹ (rotation speed 0.5 rpm) in an environment of 20 ° C. When the ink viscosity was measured under the conditions, it was 500 mPa · s.
Moreover, when the pH value of Example 1 was measured at 20 degreeC using IM-40S type | mold pH meter (made by Toa DKK Corporation), it was pH value = 8.8.

Examples 2-18
Except for changing the ink formulation as shown in the table, aqueous ballpoint pen ink compositions of Examples 2 to 18 were obtained in the same procedure as Example 1. The table shows the ink formulation and evaluation results.

Comparative Examples 1-3
Except for changing the ink formulation as shown in the table, aqueous ballpoint pen ink compositions of Comparative Examples 1 to 3 were obtained in the same procedure as Example 1. The table shows the ink formulation and evaluation results.

Test and Evaluation A ballpoint pen tip (ball) having the ink composition for water-based ballpoint pens prepared in Examples 1 to 18 and Comparative Examples 1 to 3 having a ball diameter of 0.7 mm at the tip of an ink containing cylinder and rotatably holding the ball. A refill (1.0 g) filled in an ink containing cylinder (made of polypropylene) having a diameter: 0.7 mm and an arithmetic average roughness (Ra) of the ball surface (Ra): 1 nm) via a chip holder is provided by Pilot Corporation. The following tests and evaluations were performed by attaching the gel ink ballpoint pen (trade name: G-2). In addition, the movement amount (clearance) of the ball-point pen tip in the vertical axis direction was set as shown in the table. The writing taste and the darkness of the handwriting were evaluated by the following test method using JIS P3201 writing paper A as a writing test paper.
In addition, when a spiral writing test was performed as an aqueous ballpoint pen using the aqueous ballpoint pen ink composition of Example 1, the ball pen ink consumption per 100 m was A (mg), and the ball diameter was B (mm) A = 190 (mg), the ball diameter was B = 0.7 (mm), and A / B = 271.

Handwriting Drying Performance Test After writing on the paper surface, the handwriting was rubbed with tissue paper at every elapsed time, and the handwriting state was evaluated according to the following criteria.
Written hand dried in less than 3 seconds
Written in 3 seconds or more and less than 5 seconds, and the handwriting is dry.
Written in 5 seconds or more and less than 10 seconds, and the handwriting is dry.
Written in 10 seconds or more and less than 20 seconds, and the handwriting is dry ... △
The handwriting did not dry after 20 seconds of writing

Written taste: A hand-written sensory test was performed and evaluated.
It was an extremely smooth writing taste ... ◎
It was smooth writing ...
I felt a little heavy writing taste, but it was a level that was not a problem in practical use.
He was heavy and had a poor writing feel.

Ink leak test: A 40 g weight is attached to the shaft portion of the water-based ballpoint pen for testing, and the ballpoint pen tip is discharged downward to keep the ballpoint pen tip ball in contact with the bottom of the ballpoint pen display case. The ink was left for 1 day in an environment of 65 ° C. and 65% RH, and the amount of ink leakage from the tip of the ballpoint pen tip was measured.
Ink leakage of less than 20 mg
Ink leakage amount of 20-50mg
Ink leakage amount of 50 mg to 100 mg
Ink leakage amount of 100mg or more ・ ・ ・ ×

  From the result of a table | surface, in Examples 1-18, the performance of the favorable level was obtained in the handwriting drying performance test, the writing taste, and the ink leak test.

  From the results of the table, Comparative Example 1 was inferior in the handwriting drying performance test because none of the silicone surfactants of the general formulas (Chemical Formula 1) to (Chemical Formula 3) was used.

  In Comparative Examples 2 and 3, since a surfactant other than the silicone surfactant was used, it was inferior in the handwriting drying performance test.

  Based on the above, an aqueous ballpoint pen ink comprising one or more silicone surfactants selected from the general formulas (Chemical Formula 1), (Chemical Formula 2), and (Chemical Formula 3) as the silicone surfactant. The composition can improve the handwriting dryness, improve the lubricity, and can improve the writing taste, it is found that the water-based ballpoint pen using the ink composition is excellent as a water-based ballpoint pen. It was.

  In general, a ballpoint pen tip of a water-based gel ballpoint pen has a ball held at the tip of the ballpoint pen tip so as to suppress ink leakage. It is preferable to provide a valve mechanism that presses against the inner wall to allow the ink to flow out by providing a gap between the inner wall of the tip end edge of the chip and the ball by a pressing force during writing, and closing the minute gap at the tip end when not in use.

The present invention can be used as a water-based ballpoint pen. More specifically, the present invention can be widely used as a water-based ballpoint pen such as a cap type or a retractable type.

Claims (6)

An aqueous ballpoint pen ink composition comprising water, a colorant, and a silicone surfactant, wherein the silicone surfactant is represented by the following general formulas (Chemical Formula 1), (Chemical Formula 2), and (Chemical Formula 3). An ink composition for water-based ballpoint pens, wherein one or more types are selected from the inside.

The water-based ballpoint pen ink composition according to claim 1, wherein the silicone surfactant has a weight average molecular weight of 500 to 3,000. The water-based ballpoint pen ink composition according to claim 1, wherein the colorant is a pigment. The water-based ballpoint pen ink composition according to any one of claims 1 to 3, wherein the water-based ballpoint pen ink composition comprises organic resin particles. The water-based ballpoint pen ink composition according to claim 4, wherein the organic resin particles are an olefin resin. It has a ball-point pen tip which held a ball rotatably at the tip part of an ink container, and the ink composition for water-based ball-point pens according to any one of claims 1 to 5 is stored in the ink container. A water-based ballpoint pen characterized by