JP2018051966A - Water-based ballpoint pen - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a water-based ballpoint pen capable of obtaining an excellent writing performance and handwriting, which inhibits a line skipping phenomenon, and has an excellent handwriting drying properties and further smooth feel in writing, on a writing surface with sebum such as hand grease adhering thereon.SOLUTION: A water-based ballpoint pen has a ballpoint pen tip which freely rotatably holds a ball on a tip part of an ink housing tube, and houses an ink composition for the water-based ballpoint pen in the ink housing tube. The ink composition for the water-based ballpoint pen contains water, a colorant, and a phosphate ester having an acid value of 60 to 200 mgKOH/g, and satisfies a relationship of 220≤A/B≤320 when an ink consumption per 100 m of the water-based ballpoint pen is assumed to be A (mg) and a ball diameter thereof is assumed to be B (mm).SELECTED DRAWING: None

Description

  The present invention relates to a water-based ballpoint pen. More specifically, the present invention relates to a water-based ballpoint pen capable of obtaining excellent writing properties and handwriting even on a writing surface to which sebum such as hand grease is attached.

Conventionally, a water-based ballpoint pen containing a water-based ink composition containing water as a main solvent is well known. In such a water-based ballpoint pen, the main solvent of the ink composition to be contained is water, and when the shear thinning agent is included, the shear thinning agent tends to be highly hydrophilic. Therefore, when sebum such as hand grease adheres to the writing surface at the time of writing, it is confirmed that the ink is repelled by the sebum, the ink is not applied to the paper surface, does not become handwriting, and cannot be written. Yes. (Hereinafter, this phenomenon is referred to as a line skip phenomenon.)
In order to solve such problems, Patent Document 1 discloses a ballpoint pen in which the arithmetic average roughness of the surface of the ball is set within a predetermined range and the frictional resistance with the paper surface is increased. Patent Document 2 discloses a water-based ballpoint pen ink that contains a solvent of 3-methyl-3-methoxy-1-butanol in water-based ink and that strongly adsorbs the ink to paper.

  However, in Patent Document 1, the line skip phenomenon tends to be improved, but it cannot be said that it is sufficient, and because the ball has irregularities, the writing feeling is heavy and the performance as a water-based ballpoint pen is not satisfied. Patent Document 2 describes various effects of 3-methyl-3-methoxy-1-butanol, but the 3-methyl-3-methoxy-1-butanol has high volatility and is a water-based ink composition. When it is stored for a long time, it is expected to evaporate from the refill. For this reason, there remains a problem in storage stability, and it is difficult to obtain a long-term effect such as suppression of a line skip phenomenon due to sebum accompanying evaporation, and there is room for improvement.

Japanese Patent Laid-Open No. 2002-225481 Japanese Patent Laid-Open No. 2006-102180

  The present invention, on the writing surface to which sebum such as hand fat adheres, while suppressing the line skip phenomenon, smooth writing taste and good handwriting can be obtained, and also has excellent handwriting drying performance An aqueous ballpoint pen is provided.

  The water-based ballpoint pen of the present invention is a water-based ballpoint pen having a ballpoint pen tip that rotatably holds a ball at the tip of the ink-holding cylinder, and the ink composition for the water-based ballpoint pen is stored in the ink-holding cylinder. The water-based ballpoint pen ink composition comprises water, a colorant, and a phosphoric acid ester having an acid value of 60 to 200 mgKOH / g, and the ink consumption per 100 m of the water-based ballpoint pen is defined as A. (Mg) When the ball diameter is B (mm), the relationship is 220 ≦ A / B ≦ 320.

  According to the present invention, on the writing surface to which sebum such as hand grease is attached, smooth writing taste and good handwriting can be obtained while suppressing the line skip phenomenon, and furthermore, handwriting stains due to rubbing etc. can be obtained. It is possible to provide a water-based ballpoint pen having excellent handwriting drying performance.

  The present invention relates to a water-based ballpoint pen, wherein the water-based ballpoint pen ink composition contains water, a colorant, and a phosphate ester having an acid value of 60 to 200 mgKOH / g. One characteristic is that when the ink consumption is A (mg) and the ball diameter is B (mm), the relationship is 220 ≦ A / B ≦ 320. Details will be described below.

As a result of intensive studies, the inventors of the present invention have included a phosphate ester having an acid value of 60 to 200 mg KOH / g in the ink composition, so that line jumping occurs due to repelling oil such as hand fat. It was found that the phenomenon can be effectively suppressed.
The reason for this is not clear, but is estimated as follows.
In general, anionic surfactants such as phosphate esters are neutralized with various alkalis and dissolved in an ink composition. The acid value is used as an indicator of the amount of alkali necessary for this neutralization.
By neutralizing the phosphate ester, a negative charge is generated in the phosphate group, and the phosphate ester can be adsorbed to the ball by the electrostatic attraction obtained by the generated charge. Therefore, since the phosphate ester having a specific acid value can generate an appropriate negative charge by neutralization, the ink composition containing the phosphate ester is easily adsorbed on the ball surface. For this reason, the ball surface is always kept wet with ink, the surface of the ball is not contaminated with sebum, the ball rotates without slipping on the sebum, and the ink can be reliably applied to the writing surface. It becomes. For this reason, it is estimated that the line skip phenomenon can be suppressed.

  The phosphate ester also has the effect of improving the writing quality of a water-based ballpoint pen while suppressing the line skip phenomenon. This is because the phosphoric acid ester is contained in the ink composition, so that the lubricity between the ball and the ballpoint pen tip is improved, and wear of the ball seat can be suppressed, and a smooth writing taste can be obtained. Because you can.

If the acid value of the phosphate ester is less than 60 mgKOH / g, the negative charge for adsorbing to the ball will be insufficient, and adsorption to the ball will not be sufficiently obtained. It is not possible to obtain sufficient effects. Further, if the acid value of the phosphate ester is larger than 200 mgKOH / g, the amount of alkali necessary for neutralization increases, so that an unneutralized phosphate ester is likely to be present in the ink. It is difficult to effectively obtain the effect to be brought about, and defects such as precipitates derived from phosphate esters are likely to occur.
Therefore, in the present invention, it is essential that the acid value of the phosphoric acid ester which is a constituent component is 60 to 200 mg KOH / g. An aqueous ballpoint pen having good handwriting and writing ability can be obtained while suppressing the phenomenon.
In view of further improvement of the above effect, it is more preferable to select a phosphate ester having an acid value of 80 to 200 mgKOH / g.

Furthermore, as a result of intensive studies, the present inventors have not only included a phosphoric acid ester having a specific acid value in the ink composition as described above, but also increased the ink consumption of the aqueous ballpoint pen, It was found that it was easier to obtain handwritten lines with no strokes on the writing surface with the sebum attached.
However, when the ink consumption increases, the dryness of the resulting handwriting deteriorates, and the handwriting becomes dirty due to rubbing or the handwriting is blurred.
Therefore, further investigation was made, and regarding the relationship between the specifications of the ballpoint pen tip and the ink consumption, when the ink consumption per 100 m of the water-based ballpoint pen is A (mg) and the ball diameter is B (mm), 220 ≦ A / B ≦ 320, it is understood that good handwriting and writing properties can be obtained while preventing the line skipping phenomenon due to sebum and preventing the handwriting from becoming dirty due to rubbing. It was.
As for ink consumption, a spiral writing test was performed using 5 test samples at a writing speed of 4 m / min under the conditions of 25 ° C., writing paper JIS P3201, writing angle 65 °, writing load 100 g. The average value of the ink consumption per 100 m is defined as the ink consumption per 100 m.
As a specific example, when the ball diameter is B = 0.7 mm, the ink consumption A per 100 m is set to 154 to 224 mg, whereby the relationship of 220 ≦ A / B ≦ 320 is established.
The ball diameter is not particularly limited, but a ball of about 0.1 to 2.0 mm is used.

  If the ink consumption per 100 m is A (mg) and the ball diameter is B (mm), the relationship between the ink consumption and the ball diameter will be more effective in suppressing line skipping due to sebum, smooth writing, etc. In consideration of the improvement in writing performance, it is preferable that 220 ≦ A / B, and in consideration of preventing blurring of the handwriting and handwriting due to rubbing, it is preferable that A / B ≦ 320. Furthermore, it is more preferable that 240 ≦ A / B ≦ 290 in consideration of improving the suppression of the line skip phenomenon due to sebum and obtaining good writing properties and handwriting.

  As described above, in the present invention, the ink composition contained in the water-based ballpoint pen contains a phosphoric acid ester having an acid value of 60 to 200 mgKOH / g, and further the ink consumption A per 100 m of the water-based ballpoint pen. By making the relationship between (mg) and the ball diameter B (mm) 220 ≦ A / B ≦ 320, the line skip phenomenon is suppressed even on the writing surface where sebum such as hand fat is attached, and It is possible to obtain a water-based ballpoint pen that has a smooth writing taste and can prevent handwriting smearing due to handwriting bleeding and rubbing, and has excellent writing properties and handwriting.

  The water-based ballpoint pen ink composition housed in the water-based ballpoint pen of the present invention comprises water, a colorant, and a phosphate ester having an acid value of 60 to 200 mgKOH / g. The components of the composition will be described in more detail.

Examples of the phosphoric acid ester used in the present invention include polyoxyethylene alkyl ether or polyoxyethylene alkyl aryl ether phosphoric acid monoester, polyoxyethylene alkyl ether or polyoxyethylene alkyl aryl ether phosphoric acid diester, polyoxyethylene Examples include phosphoric acid triesters of alkyl ethers or polyoxyethylene alkyl aryl ethers, alkyl phosphoric acid esters, alkyl ether phosphoric acid esters or derivatives thereof, and the alkyl groups of the phosphoric acid esters include styrenated phenols, nonylphenols, Examples include octylphenol type and linear alcohol type.
Among these, in consideration of improvement of the line skip phenomenon due to sebum such as hand fat, a linear alcohol phosphate in which the alkyl group of the phosphate ester is a linear alcohol is preferable, and the linear alcohol phosphorus is preferable. Examples of the acid ester include lauryl alcohol, tridecyl alcohol, octyl alcohol, and stearyl alcohol.
You may use these individually or in mixture of 2 or more types.

Among them, it is more preferable to select a linear alcohol phosphate having an alkyl group having 8 to 14 carbon atoms. The reason is not clear, but if the number of carbon atoms is 8 or more, the bulk of the phosphoric acid ester molecule is large, and the film thickness of the phosphoric acid ester formed on the ball surface can be sufficiently ensured. This is because a sufficient suppression effect can be obtained. In addition, when the number of carbon atoms is 14 or less, there is no steric repulsion between hydrophobic groups, and a uniform phosphate ester film can be formed on the ball surface. This is because the lubricity between the chips can be improved and the writing performance can be improved, such as a smooth writing taste.
Furthermore, in consideration of the improvement of the above effects, it is more preferable to use a linear alcohol (octyl alcohol) phosphate ester having 8 carbon atoms in the ink composition of the present invention. This is presumed to be because the linear alcohol type (octyl alcohol type) phosphate ester having 8 carbon atoms can form the most uniform film on the ball surface.
In addition, some of the phosphoric acid esters have an effect of improving handwriting dryness, and considering this, a linear alcohol type having 8 or 13 carbon atoms (octyl alcohol type or tridecyl alcohol type). In view of further consideration, it is preferable to select and use a linear alcohol type (octyl alcohol type) phosphate ester having 8 carbon atoms.

  Specific examples of the phosphoric acid ester include Prisurf series (Daiichi Kogyo Seiyaku Co., Ltd.) and Phosphanol series (Toho Chemical Co., Ltd.). Examples of the styrenated phenolic phosphate ester include Prisurf AL (acid value: 70 to 95, HLB: 5.6). Examples of the lauryl alcohol type in the linear alcohol type phosphate ester include Prisurf A208B (acid value: 160 to 185, HLB: 6.6). Examples of the tridecyl alcohol type include Prisurf A212C (acid). Value: 100 to 120, HLB: 9.4), Plysurf A215C (acid value: 80 to 95, HLB: 11.5), and the octyl alcohol type includes Plysurf A208F (acid value: 165 to 195). , HLB: 8.7). Moreover, as a stearyl alcohol type, phosphanol RB410 (acid value: 80-90, HLB: 8.6) is mentioned. These phosphate esters may be used alone or in combination of two or more.

Further, among the phosphoric acid esters, in consideration of improvement of the line skip phenomenon due to sebum such as hand fat, 0.5% aqueous solution containing the phosphoric acid ester (water 96.5% by mass, triethanolamine 3% by mass). The dynamic surface tension of the phosphoric acid ester is preferably 30 to 65 mN / m.
The dynamic surface tension is a surface tension (that is, a surface tension at a moving gas-liquid interface) in a state where the liquid is moving (flowing state), and is measured by a maximum bubble pressure method in the present invention. The maximum bubble pressure method measures the maximum pressure (maximum bubble pressure) in milliseconds when a bubble is generated from the tip of a capillary (probe) inserted in the liquid (that is, when a new interface is formed). In this way, the surface tension (mN / m) of the liquid is obtained.
Specifically, a bubble is discharged from the probe tip to generate a new bubble surface (t1), and the radius of curvature is minimized and the pressure is maximized (t2) when the next bubble grows (specifically, The pressure becomes maximum when the radius of curvature R of the bubble and the radius r of the probe tip are equal. Thereafter, the bubbles further grow and are released from the probe tip again (t3). Note that t1 to t3 are time t in each state. The pressure change is repeated by repeating the generation of bubbles in the above-described process. In particular, in the elapsed time, the time from the generation of a new surface to the maximum pressure (between t1 and t2) is defined as the lifetime (between t1 and t2). The life of bubbles is called dead time.
As the lifetime is shorter, a surface tension in a dynamic state where the liquid moves is obtained, and as the lifetime is longer, a surface tension in a static state where the liquid does not move is obtained.
In the present invention, the surface tension value when the most dynamic lifetime is 10 ms is defined as the dynamic surface tension.

In the present invention, in order to prevent the water-based ink composition from being repelled on the writing surface to which oil called sebum is adhered, not only the surface tension (static surface tension) of the ink composition but also dynamic It has been found that it can be a more suitable index by considering the surface tension. Therefore, a 0.5% aqueous solution (containing 96.5% by weight of water, 3% by weight of triethanolamine, and 0.5% by weight of phosphate ester) containing a phosphate ester has a surface tension of 10 ms as described above. That is, it is preferable to select a phosphate ester having a dynamic surface tension within the above range, and to include it in the water-based ink composition. This is because the water-based ballpoint pen ink composition contains the phosphoric acid ester, so that the liquid starts moving as the ball begins to rotate and the ink interface starts moving (flowing state). The surface tension (that is, the surface tension at the moving gas-liquid interface) can be greatly reduced, which dramatically improves the wettability of the ink composition to the paper surface and the ball surface. Boss, said ink composition, it is possible to wet the previously ball surface than sebum. For this reason, it is assumed that the ball rotates without slipping without being affected by sebum, so that the ink can be surely placed on the writing surface.
From the above, by including the phosphate ester in the ink composition, the ink composition can be applied to the writing surface without being repelled even on the writing surface to which oil called sebum adheres, and good handwriting can be obtained. I think you can leave.

The dynamic surface tension is measured by the maximum bubble pressure method using a dynamic surface tension measuring machine (manufactured by Kyowa Interface Science Co., Ltd., BP-D3 or BP-D5), a bubble pressure dynamic surface tension meter (manufactured by KRUSS, BP-2). ) And the like.
In the present invention, BP-D5 manufactured by Kyowa Interface Science Co., Ltd. is used, and automatic measurement is performed under the conditions of gas for bubble generation: air, measurement temperature: 20 ° C., and sample volume of 75 mL. Moreover, the dynamic surface tension of deionized water is measured on the same conditions as a blank.

  Furthermore, in consideration of suppression of line skipping phenomenon due to sebum, improvement of handwriting and writing property, and handwriting drying property, 0.5% aqueous solution containing the above phosphate ester (water 96.5% by mass, triethanolamine 3 It is more preferable to select and use a phosphoric acid ester having a dynamic surface tension of 30 to 58 mN / m, including a phosphoric acid ester of 30 to 50 mN / m. It is more preferable to select and use.

  Moreover, it is preferable that the HLB value of the said phosphate ester is 5-14. When the HLB value of the phosphate ester is within the above numerical range, the phosphate ester effect can be sufficiently obtained without remaining in the solvent water. Furthermore, in view of improvement of the line skip phenomenon due to sebum, it is more preferable to select a phosphate ester having an HLB value of 8 to 13.

  The content of the phosphate ester in the ink composition for water-based ballpoint pens is preferably 0.1 to 5% by mass, and 0.5 to 3% by mass based on the total mass in the ink composition. It is more preferable. If the content of the phosphate ester is within the above numerical range, the effect of the phosphate ester can be sufficiently obtained, and the line skipping phenomenon caused by sebum can be effectively improved. Further, since the surface tension of the ink composition is not extremely reduced, the handwriting does not blur and a good handwriting can be obtained. Further, since the lubricity between the ball and the ballpoint pen tip can be improved, the writing property can be improved, such as a smooth writing taste.

<Colorant>
In the colorant that can be used in the present invention, dyes, pigments, and the like that are usually used in water-based ballpoint pen ink compositions can be used.

  The dye that can be used in the present invention is not particularly limited as long as it can be dissolved in an aqueous medium. Examples thereof include various dyes such as acid dyes, basic dyes, reactive dyes, direct dyes, disperse dyes and food dyes, and these can be used alone or in combination of two or more.

  Specifically, examples of the acid dye include C.I. I. Acid Red 18, C.I. I. Acid Red 51, C.I. I. Acid Red 52, C.I. I. Acid Red 87, C.I. I. Acid Red 92, C.I. I. Acid Red 289, C.I. I. Acid Orange 10, C.I. I. Acid Yellow 3, C.I. I. Acid Yellow 7, C.I. I. Acid Yellow 23, C.I. I. Acid Yellow 42, C.I. I. Acid Green 3, C.I. I. Acid Green 16, C.I. I. Acid Blue 1, C.I. I. Acid Blue 9, C.I. I. Acid Blue 22, C.I. I. Acid Blue 90, C.I. I. Acid Blue 239, C.I. I. Acid Blue 248, C.I. I. Acid Violet 15, C.I. I. Acid Violet 49, C.I. I. Acid Black 1, C.I. I. Acid Black 2 and basic dyes include C.I. I. Basic Orange 2, C.I. I. Basic Orange 14, C.I. I. Basic Green 4, C.I. I. Basic Blue 9, C.I. I. Basic Blue 26, C.I. I. Basic Violet 1, C.I. I. Basic Violet 3, C.I. I. Basic violet 10 includes C.I. I. Direct Red 28, C.I. I. Direct Yellow 44, C.I. I. Direct Blue 86, C.I. I. Direct Blue 87, C.I. I. Direct violet 51, C.I. I. As direct black 19, food coloring, C.I. I. Food Yellow 3, C.I. I. Food black 2 etc. are mentioned.

  The pigment that can be used in the present invention is not particularly limited as long as it can be dispersed in an aqueous medium. For example, inorganic, organic, processed pigments, etc. are mentioned, specifically, carbon black, aniline black, ultramarine, yellow lead, titanium oxide, iron oxide, phthalocyanine, azo, quinacridone, quinophthalone, selenium, Examples thereof include triphenylmethane, perinone, perylene, dioxazine, aluminum pigment, pearl pigment, fluorescent pigment, and phosphorescent pigment. In addition, a microcapsule pigment in which a colored body in which a pigment is dispersed in a medium as a colored resin particle body is encapsulated or solidified in a shell made of a resin wall film forming substance by a known microencapsulation method may be used. good.

  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 acidic resins, nonionic surfactants and anionic surfactants.

  Moreover, you may use the said pigment and dye as a coloring agent individually or in combination of 2 or more types. The content of the colorant in the water-based ink composition is preferably 0.1 to 20% by mass based on the total mass of the water-based ink composition. When the content of the colorant is within the above numerical range, it is possible to prevent the discharge property of the ink composition from being lowered and to obtain a handwriting with good color development.

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

<Others>
The water-based ink composition used in the present invention may contain various additives for the purpose of improving ink physical properties and functions. Specifically, water-soluble organic solvents to prevent water evaporating and drying, water-soluble organic solvents, pH regulators to improve colorant stability over time, nonionic interfaces to improve lubricity Surfactants such as activators, anionic surfactants, cationic surfactants, preservatives such as 1,2-benzisothiazolin-3-one, humectants such as urea and sorbit, rust inhibitors such as benzotriazole A chelating agent such as ethylenediaminetetraacetic acid, a shear-thickening agent such as a cross-linked acrylic acid polymer, and xanthan gum can be added. Various resin particles such as acrylic resin, styrene-butadiene resin, silicone resin, urethane resin, and olefin resin can also be added. The above additives can be used alone or in combination of two or more.

  Examples of the water-soluble organic solvent include polyhydric alcohol solvents such as ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, polyethylene glycol, and glycerin, methanol, ethanol, 1-propanol, 2-propanol, isopropanol, isobutanol, t- Alcohol solvents such as butanol, allyl alcohol, 3-methyl-1-butyn-3-ol, ethylene glycol monomethyl ether acetate and other higher alcohols, glycol ethers such as ethylene glycol monomethyl ether and ethylene glycol monoethyl ether A solvent etc. are mentioned. Among these, it is preferable to use a polyhydric alcohol solvent in view of the dissolution stability with the phosphate ester used in the present invention. The polyhydric alcohol solvent is a solvent in which two or more hydroxyl groups are bonded to different carbon atoms of an aliphatic or alicyclic compound, and among them, a polyhydric alcohol having a divalent or trivalent hydroxyl group. It is most preferable to contain at least. You may use these individually or in mixture of 2 or more types. The content of the water-soluble organic solvent in the water-based ink composition is preferably 0.1 to 30% by mass based on the total mass of the water-based ink composition.

  As for pH of the water-based ink composition used for this invention, 7-11 are preferable. 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).

  In order to adjust the ink composition to a preferable pH, it is preferable to include a pH adjusting agent. Examples of the pH adjuster include inorganic salts such as ammonia, sodium carbonate, sodium phosphate, sodium hydroxide and sodium acetate, organic basic compounds such as alkanolamines such as triethanolamine and diethanolamine, lactic acid and citric acid, and the like. It is done. In view of the stability with the phosphate ester and obtaining the effect of the phosphate ester efficiently, it is preferable to use an alkanolamine. It is preferable to use it. These pH adjusters may be used alone or in combination of two or more. The content of the pH adjuster is preferably 0.1 to 10% by mass, more preferably 0.1 to 5% by mass, based on the total mass of the water-based ink composition.

In addition, the ink viscosity of the aqueous ballpoint pen ink composition used in the present invention is preferably 1000 to 5000 mPa · s at a shear rate of 1.92 sec ⁻¹ in a 20 ° C. environment, and the ink viscosity is within the above numerical range. Then, since the ink consumption can be adjusted appropriately, it is possible to effectively suppress the line skipping phenomenon due to sebum and to obtain an aqueous ballpoint pen having good handwriting and smooth writing. Considering the line skipping phenomenon due to sebum, it is effective to reduce the viscosity and increase the ink consumption, but it is easy to bleed the handwriting or prevent sedimentation of the pigment when using a pigment as the colorant. It becomes difficult. Therefore, if the above is further considered, the ink viscosity is more preferably 2000 to 3000 mPa · s.

  In order to adjust the ink composition to a preferable ink viscosity, the ink composition preferably includes an ink viscosity modifier, and a shear thinning agent is preferably used as the ink viscosity modifier. Examples of shear thinning agents include cross-linked acrylic acid polymers, polysaccharides, associative thickeners, etc., and polysaccharides include xanthan gum, welan gum, succinoglycan, guar gum, locust bean gum, λ-carrageenan, Associative thickeners such as cellulose derivatives and diutan gum, associative hydrophobic groups, polyester-based, polyether-based, urethane-modified polyether-based, polyaminoplast-based, alkali-swelled associative thickeners, nonions Examples include associative thickeners. These shear thinning agents may be used alone or in combination of two or more. Among these, considering the ink aging stability, it is preferable to use a polysaccharide, and it is more preferable to use at least xanthan gum. This is because xanthan gum has a tendency that it is difficult for crying to occur, and by using xanthan gum, it is possible to obtain a good handwriting without causing the handwriting to rub and rub the handwriting.

Moreover, you may add a resin particle arbitrarily to the water-based ink composition used for this invention. By including the resin particles in the ink composition, the resin particles can enter between the ball and the ball seat, improve the writing quality by the cushion effect, and suppress wear of the ball seat. It is preferable because the writability and handwriting can be improved.
The resin particles also have an effect of causing a physical failure in the gap between the ball and the inner wall of the tip of the chip and suppressing ink leakage from the tip of the chip.
In the water-based ink composition accommodated in the ballpoint pen of the present invention, when the ink consumption per 100 m is A (mg) and the ball diameter is B (mm), the relationship between the ink consumption and the ball diameter is 220 ≦ It is essential that A / B ≦ 320, and as will be described later, the movement amount (clearance) of the ball-point pen tip in the vertical axis direction is preferably 20 to 45 μm. When such a ballpoint pen is exposed to a cap-off condition, such as a retractable ballpoint pen, the ink may leak from the gap between the ball and the inner wall of the tip of the ballpoint pen tip. High nature. Therefore, it is preferable to include the resin particles in the ink composition used in the present invention, because ink leakage from the tip of the chip can be effectively suppressed.
Among the resin particles, it is preferable to select and use olefin resin particles in the present invention. The olefin-based resin particles are partly deformed and are in close contact with each other, making it easy to suppress ink leakage and stable even when sandwiched between a ball and a ball seat. This is because the effect is obtained, the writing quality is further improved, and the wear of the ball seat can be suppressed.

Moreover, it is preferable that the surface tension (static surface tension) of the ink composition for water-based ball-point pens used for this invention is 10-40 mN / m in a 20 degreeC environment.
As described above, it is preferable to consider the surface tension (static surface tension) of the ink composition in suppressing the line skip phenomenon due to sebum. The ink composition used in the present invention has a relationship between the ink consumption and the ball diameter of 220 ≦ A / B, where the ink consumption per 100 m is A (mg) and the ball diameter is B (mm). Since it is ≦ 320, ink leakage from the tip of the tip may occur depending on the form of the ballpoint pen used and the environment used, and it is preferable to adjust the surface tension appropriately. If the surface tension of the ink composition is 10 mN / m or more, ink leakage from the tip of the tip, and handwriting smearing due to blotting or rubbing of the handwriting can be suppressed. Can effectively improve the line skip phenomenon. Considering the improvement of the effect, it is preferably 30 to 40 mN / m.
The surface tension represents a static surface tension, and is obtained by measuring by a vertical plate method using a platinum plate with a surface tension measuring instrument manufactured by Kyowa Interface Science Co., Ltd. in a 20 ° C. environment.

The water-based ballpoint pen of the present invention has a ballpoint pen tip that rotatably holds the ball at the tip of the ink containing cylinder, and the arithmetic average roughness (Ra) of the surface of the ball is 0.1 to 5 nm. preferable. When the arithmetic average roughness (Ra) of the surface of the ball is 0.1 nm or more, the ink is sufficiently deposited on the surface of the ball, and the line skip phenomenon due to sebum can be sufficiently improved. 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 particular, an ink composition comprising a phosphoric acid ester having an acid value of 60 to 200 mgKOH / g is effective because it has a surface arithmetic mean roughness (Ra) that is easily on the surface of the ball within the above numerical range. Is.
In consideration of improving the line skip phenomenon due to sebum and obtaining a smooth and good writing quality, the arithmetic average roughness (Ra) of the surface of the ball is preferably 0.5 to 3 nm.
Note that the arithmetic average roughness (Ra) is a reference length extracted in the direction of the average line from a roughness curve measured by a surface roughness measuring instrument (model name SPI3800N, manufactured by Seiko Epson Corporation). The absolute value of the deviation from the average line of the extracted portion to the measurement curve is summed and averaged.

  The material of the balls is not particularly limited, and examples thereof include cemented carbide balls mainly composed of tungsten carbide, silicon carbide, alumina, zirconia, and silicon nitride. In particular, a cemented carbide ball is preferable because it is low-cost, and ink tends to spread on the surface of the ball, and it tends to be satisfactorily written on the writing surface contaminated with sebum such as hand grease, without line skipping phenomenon. . Further, the phosphate ester used in the present invention has good compatibility with the cemented carbide ball, and by including it in the ink composition, effectively improves the wettability of the ink composition to the cemented carbide ball. Can do. Therefore, it is preferable to use a cemented carbide ball for the ballpoint pen of the present invention, and the line skip phenomenon due to sebum can be effectively improved.

Moreover, it is preferable that the movement amount (clearance) of the ball-point pen tip used in the present invention in the vertical axis direction is 20 to 45 μm. This is because the movement amount (clearance) is in the above numerical range, and 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). Can be easily set to 220 ≦ A / B ≦ 320, preventing the line skipping phenomenon caused by sebum, but without smearing the handwriting, rubbing the crying and rubbing the handwriting, and obtaining good handwriting and writing properties. It is because it becomes easy to be done. In consideration of the above effect, 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.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to these Examples.

<Example 1>
An aqueous ballpoint pen was obtained by the following composition and method.
・ Coloring agent 20.0% by mass
(Carbon black, trade name: Fuji SP Black 8041 solid content 20%)
・ Surfactant 1.0% by mass
(Phosphate ester, trade name: Prisurf A208F, acid value of 165 to 195)
・ Shear thinning agent 0.5% by mass
(Xanthan gum, trade name: Keldent)
・ PH adjuster 3.0% by mass
(Triethanolamine)
・ Water-soluble organic solvent 20.0% by mass
(Diethylene glycol)
・ Preservative 0.5% by mass
(1,2-Benzisothiazol-3-one, trade name: Proxel XL-2 (S))
・ Water balance

A base ink was prepared by heating and stirring a colorant, a surfactant, a pH adjuster, a water-soluble organic solvent, a preservative, and water with a magnetic hot stirrer.
Then, while heating the base ink prepared above, the shear thinning agent was added and mixed and stirred thoroughly until homogenized using a homogenizer stirrer, and then filtered using filter paper. An ink composition for water-based ballpoint pens used in Example 1 was obtained.
In addition, when the surface tension of the obtained ink composition for water-based ballpoint pens was measured with a surface tension measuring instrument (in a 20 ° C environment, a platinum plate, a vertical plate method, manufactured by Kyowa Interface Science Co., Ltd.), 34.5 mN / m. Met.
In addition, the viscosity of the water-based ink composition was measured using an E-type rotational viscometer (model: DV-II + Pro, rotor: CPE-40, manufactured by Brookfield) at a shear rate of 1.92 sec ⁻¹ (rotational speed) in a 20 ° C. environment. When the ink viscosity was measured under the condition of 0.5 rpm, it was 2300 mPa · s.
Furthermore, as a result of measuring the pH of the aqueous ink composition at 20 ° C. using an IM-40S type pH meter (manufactured by Toa DKK Co., Ltd.), the pH was 8.5.

  An ink having a ballpoint pen tip at the tip of which the obtained water-based ballpoint pen ink composition is rotatably held by a cemented carbide ball having a diameter of 0.7 mm and a surface arithmetic average roughness (Ra) of 1 nm. A refill was prepared by directly packing inside the housing cylinder, and this refill was mounted on a gel ink bow pen (trade name: G-2) manufactured by Pilot Corporation to obtain an aqueous ballpoint pen. The movement amount (clearance) of this gel ink ballpoint pen in the vertical axis direction was 30 μm.

<Example 2 to Example 11>
In Examples 2 to 11, water-based ballpoint pens were obtained in the same manner as in Example 1 except that the types and amounts of components contained in the ink composition were changed to the compositions shown in Table 1.

<Comparative Examples 1 to 6>
In Comparative Examples 1 to 6, water-based ballpoint pens were obtained in the same manner as in Example 1 except that the types and amounts of components contained in the ink compositions were changed to the compositions shown in Table 2.

<Test and evaluation results>
The following tests and evaluations were performed using the water-based ballpoint pens prepared in Examples 1 to 11 and Comparative Examples 1 to 6.

<Sebum writing performance test>
Artificial sebum was prepared by mixing and stirring the following components and blending amounts, and a solution (sebum diluted solution) was prepared by diluting the prepared artificial sebum to 50% with acetone. This diluted sebum solution was uniformly applied to writing paper according to JIS P3210, and acetone was dried to prepare a sebum-resistant writing test paper.
On this sebum-resistant writing test paper, 100 characters were written with the water-based ballpoint pens of Examples 1 to 11 and Comparative Examples 1 to 6, and the number of characters in which line skipping occurred was counted. According to the following criteria, the writing performance (sebum resistance writing performance) on the paper surface to which sebum adhered was evaluated. The evaluation results obtained are summarized in Tables 1 and 2.
Artificial sebum: 33.3 wt% triolein, 20 wt% oleic acid, 1.3 wt% squalane, 33.4 wt% myristyl octadodecylate
(Double-circle): The number of the letters which skipped was 15 or less, and the sebum-proof writing performance was very favorable.
○: The number of skipped characters was 16 to 20, and the sebum resistance writing performance was good.
[Delta]: 21 to 50 stroked characters, sebum resistance is slightly inferior, and there is a little concern for practical use.
X: There are 51 to 100 skipped characters, the sebum writing resistance is poor, and there is a problem in practical use.

<Writing performance test>
Writing was performed on writing test paper (JIS P3210 writing paper A) with a water-based ballpoint pen used in the sebum resistance writing test, and writing performance was evaluated according to the following criteria by sensory test. The evaluation results obtained are summarized in Tables 1 and 2.
(Double-circle): It was very smooth writing taste.
○: Smooth writing taste.
Δ: A slightly heavy writing taste was felt, but it was at a level of no practical problem.
X: The writing taste was heavy and slippery.

<Handwriting drying performance test>
The handwriting obtained by writing was scraped with a finger after 15 seconds, and the handwriting state was evaluated according to the following criteria for the state of the handwriting.
A: The handwriting after rubbing was not soiled and a good handwriting remained.
○: Slight dirt was observed in the handwriting after rubbing, but it was at a level with no practical problem.
X: The handwriting after rubbing is dirty and has practical problems.

<Dynamic surface tension (0.5% aqueous solution containing phosphate ester)>
96.5% by mass of water, 0.5% by mass of phosphate ester and triethanolamine were heated and stirred with a magnetic hot stirrer to prepare a 0.5% aqueous solution containing the phosphate ester.
As phosphate ester, prototype 1 was selected as Prisurf A208F, prototype 2 was selected as Prisurf A215C, and prototype 3 was selected as Prisurf AL to prepare a 0.5% aqueous solution containing phosphate ester.
The dynamic surface tensions of 0.5% aqueous solutions containing the phosphate esters of trial production 1 to 3 were as follows when the measurement temperature was 20 ° C. and the lifetime was 10 ms.
Trial 1: 39.0 mN / m, Trial 2: 56.0 mN / m, Trial 3: 64.3 mN / m

From Table 1, the water-based ballpoint pens of Examples 1 to 11 show a very low frequency of occurrence of the line skip phenomenon on the writing surface to which sebum such as hand oil is attached, from the <Sebum Resistance Writing Performance Test>. From <Writing Performance Test>, it can be confirmed that it has an extremely smooth writing taste, and <Handwriting Drying Performance Test> indicates that the handwriting is not soiled by rubbing. Sebum resistance writing performance, writing performance, handwriting All of the drying performance was satisfied.
From Table 2, the water-based ballpoint pens of Comparative Examples 1 to 6 did not satisfy all of the sebum resistance writing performance, writing performance, and handwriting drying performance.
As mentioned above, the ink composition to contain contains the phosphate ester whose acid value is 60-200 mgKOH / g, and the relationship between the ink consumption per 100 m A (mg) and the ball diameter B (mm) is 220 ≦ It was found that the water-based ballpoint pen satisfying A / B ≦ 320 was excellent in sebum resistance writing performance, writing performance, and handwriting drying performance, and was excellent as a water-based ballpoint pen.

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. In particular, it can be suitably used for a retractable water-based ballpoint pen.

Claims (4)

  A water-based ballpoint pen having a ballpoint pen tip that rotatably holds a ball at the tip of an ink-holding cylinder, wherein the ink composition for the water-based ballpoint pen is stored in the ink-holding cylinder, and the ink for the water-based ballpoint pen The composition comprises water, a colorant, and a phosphate ester having an acid value of 60 to 200 mgKOH / g, and the ink consumption per 100 m of the water-based ballpoint pen is A (mg), the ball diameter Is a relationship of 220 ≦ A / B ≦ 320, where B is (mm).   The aqueous ballpoint pen according to claim 1, wherein the phosphate ester is a linear alcohol phosphate ester.   3. The water-based ballpoint pen according to claim 1, wherein an arithmetic average roughness (Ra) of the surface of the ball is 0.1 to 5 nm. The water-based ballpoint pen according to claim 1, wherein an amount of movement of the ballpoint pen tip in the vertical axis direction is 20 to 45 μm.