TWI328027B - Water-based ink composition for fine pointed ballpoint pen and fine pointed ballpoint pen - Google Patents

Description

139. The invention relates to an aqueous ink composition for a ball pen, and in particular, relates to a ball diameter of 0.5 mm or less (especially 0 _ 4 mm or less). The fine-grained atomic pen tip has an excellent water-absorbent composition for the ball-type pen, and a fine-grain pen for excellent anti-wear properties, scribing properties, ink-discharging properties, and time stability. [Prior Art] When writing with a ballpoint pen, the ink is transferred to the writing surface by the rotation of the sphere, and when the sphere is rotated, the component that fixes the sphere and contacts the inside of the tip of the atomic pen (the outer cover of the ball) is worn, thus The clogging of the ink outlet or the quilting of the fixed sphere may come into contact with the paper surface, causing writing problems such as ink breakage and inability to write. Therefore, attempts have been made to add a water-soluble cutting oil and a surfactant to a ball pen ink as an anti-wear agent or to blend an ink with a solid lubricant such as boron nitride, a wax emulsion or a resin particle. However, the current wear resistance of the cover of the atomic pen tip has not been satisfactory. In addition to this, it has been proposed (for example, Japanese Patent Application Laid-Open No. 206066/2002) to have fine particles having a particle diameter of 0.1 μm or more and 30 μm or less (for example, a new Mohs hardness of 4 or more). Alumina, tantalum carbide and chromium oxide are added to the ink composition to improve the abrasion resistance of the ball cover of the ballpoint tip. However, this method will cause the following problems: that is, the writing feeling will be deteriorated and the scribe line property will be different due to the direction ((2) (2) 1328027, where the amount of ink will be uneven depending on the writing direction) and The jumping phenomenon (where the rotation of the sphere temporarily stops and the sphere slides on the paper to interrupt the scribe line) is lowered. Specifically, when the ball diameter of the fine ball pen is 0.5 mm or less, it is not always available to effectively suppress the abrasion of the outer cover of the ball to achieve a certain level of writing quality. The reason is as follows. Taking the fine-grain pen as an example, since the area of the outer cover of the ball is smaller than that of the ordinary one, the load per unit area is large, so the friction resistance is high and the wear is remarkable. In addition, since the ink outlet is small, it is easy to cause problems due to clogging during writing. In addition, since the ball diameter of the thin ball pen is small and the portion of the ball protruding from the pen tip is small, the wear of the outer cover causes the protruding portion of the ball to become smaller, so that the quilting member that fixes the ball may come into contact with the paper surface, causing problems, including Poor writing, such as broken ink and unable to write. Therefore, the fine-grained ball pen has a problem of accelerated wear, and in addition, it is less resistant to abrasion and the writing quality is not easily maintained. Therefore, the HU 5, which runs out of ink, is highly likely to cause serious inconvenience due to the inability to write, and it also increases the difficulty in designing the fine ball pen. Specifically, when the ball diameter of the fine ball pen is 0.4 mm or less, the frictional resistance is further increased, and the wear of the outer cover becomes more conspicuous. In addition, it is difficult for the sphere to rotate smoothly, which may cause serious problems such as poor writing sensation and a decrease in the scribe line property due to the difference in direction and jumping phenomenon. In addition, since the area of the ink discharge port of the small ball diameter pen is smaller, the ink discharge property is deteriorated, so the viscosity of the ink is usually lowered. However, when the fine particles are blended with the ink, the 'larger particles will settle with the passage of time' and thus cause a poor writing quality, deterioration of the ink discharge property, and serious problems such as poor writing (caused by settlement due to clogging). The above problems are best solved at the beginning of -6-(3) (3) 1328027. Therefore, in a fine-grain pen with a spherical diameter as small as 0.5 mm or less, 'only adding fine particles having a particle diameter of 〇. 1 μm or more and 30 μm or less cannot effectively suppress the abrasion of the outer cover, and there is a scribing property. Deterioration, poor writing sensation, such as a decrease in ink discharge and poor writing (caused by clogging due to sedimentation). SUMMARY OF THE INVENTION An object of the present invention is to provide an aqueous ink composition for a fine-grain pen for suppressing wear of an outer cover and having excellent ink-discharging properties and time stability, and having a smooth writing feeling and capable of writing for a long time. ball-point pen. SUMMARY OF THE INVENTION In order to solve the above problems, the inventors have made repeated and in-depth research on the abrasion resistance, scribing property, writing feeling, fine grain anti-settling property and time stability of the outer shell of the small ball diameter fine ball pen. And found that these problems can be selected from aluminum oxide, oxidized crystal, oxidized sand, carbonized sand and tungsten carbide, and the ultrafine particles having an average particle diameter of less than 0.1 μm are added to the ink and the ink viscosity is lowered to some A specific defect or the following is solved. The invention has thus been completed. That is, the present invention relates to: (1) an aqueous ink composition for a fine-grain pen, characterized in that the composition is an ink composition containing at least water, a colorant and a water-soluble solvent, and at least one selected from the group consisting of oxidizing Aluminum, titanium oxide, cerium oxide, lanthanum carbide and tungsten carbide and ultrafine particles having an average particle diameter of less than 0.1 μm are blended to obtain (4) (4) 1328027, wherein the ultrafine particles are based on the blending amount of the ink composition It is 0.002 to 2% by weight. (2) The aqueous ink composition for a fine-grain pen of the above item (1), which has a viscosity of 50 to 2000 mPa's measured at 1 rpm (H4'R24 corn ) by a cone-and-plate type rotational viscometer (25) °C). (3) A fine-grain pen which is filled with an aqueous ink composition of the above item (1) or (2) having a spherical diameter of 0.4 mm or less. When the above aqueous ink composition of the present invention is used for a fine-grain pen, it can eliminate deterioration of scribing properties (e.g., direction difference and jumping phenomenon) and avoid deterioration of writing feeling, ink discharging property, and temporal stability. In addition, it can improve the anti-wear effect of the atomic nib and extend the writing distance. When used for a fine-grain pen with a ball diameter of 0.4 mm or less (especially 0.28 mm or less), the effect is most remarkable. [Embodiment] The best mode for carrying out the invention will be described in detail below. The alumina, titanium oxide, cerium oxide cerium carbide and tungsten carbide fine particles contained in the ink composition of the present invention containing at least water, a colorant and a water-soluble solvent must be very fine to suppress abrasion of the outer cover and improve the ink in the ink. The dispersion stability in the composition, and it is preferably ultrafine particles having an average particle diameter of less than 0.1 μm and preferably spherical to improve the writing feeling. The ultrafine particles referred to herein mean fine particles having a particle diameter of 0.001 to less than 0.1 μm. The preferred ultrafine particle oxidation includes alumina C (main particle size: 0.013 μm) manufactured by Nippon Aerosil Co., Ltd., C. I. Kasei -8- (5) (5) 1328027

Nano Tec Al2〇3 (main particle size: 0.03 3 μm) manufactured by Co., Ltd. and T aimicr ο η T Μ -1 0 0 J manufactured by Taimei C he mica 1 s C ο ., L td . Particle size: 0.014 microns). The ultrafine particle titanium oxide includes titanium oxide P25 (main particle diameter: 0.03 μm) manufactured by Nippon Aerosil Co., Ltd. and TTO-55A (main particle diameter: 0.0 5 μm) manufactured by Ishihara Sangyo Kaisha Ltd. In the present invention, the ultrafine particles selected from the group consisting of alumina, titania, cerium oxide, cerium carbide and tungsten carbide and having an average particle diameter of less than 0.1 μm are based on the content of the ink composition of 0.002 to 2% by weight. Preferably, it is more preferably 0.05 to 1% by weight. The ultrafine particles may be used singly or in combination of two or more kinds in the above range. When the ball diameter of the fine ball pen is 0.5 mm or less, fine particles having a particle diameter of 0.1 μm or more are less likely to provide a satisfactory effect in suppressing abrasion of the outer cover. Further, when the ball diameter of the fine ball pen is 0.4 mm or less, disadvantages such as poor writing due to abrasion of the cover, poor writing feeling, reduced scribe line property, and clogging due to settlement are often caused. In particular, when the ball diameter of the fine ball pen is 0.28 mm or less, the reduction of the ink discharge port and the reduction of the ball protrusion and the increase in the abrasion resistance significantly degrade the writing performance over time. Therefore, the fine-grain pen has become an essential condition using ultrafine particles having an average particle diameter of less than 0.1 μm. If the content exceeds 2% by weight, the writing feeling and ink discharge property may be lowered and the abrasion resistance may be deteriorated. The above-described ink composition of the present invention has a viscosity of 50 to 2000 mPa·s (25 ° C), and 100 to 100〇1^&.5 (25°(:) is preferred (6) (6) 1328027, and the viscosity is measured at 1 rpm (l°3m24 corn) using a cone-and-plate rotary viscometer. When the above viscosity is lower than 50 m P a · s (25 ° C), the above ultrafine particles may settle over time and may cause ink leakage and occasionally unwritten conditions. If the viscosity is above 2000 mPa .s (25 ° C ) 'The ink discharge is lowered and occasionally the writing feeling is deteriorated, so it is not suitable. The water-soluble solvent in the ink composition of the present invention is used for, for example, preventing the ink from being cold. Freezing and preventing the ink of the nib from drying out, etc. Specifically, 'it includes ethylene glycols such as ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, polyethylene glycol, 1,3-butanediol, sulfur Diethylene glycol, glycerin, methoxyethanol and methoxyethoxyethanol, which may be used singly or in combination. The amount of the substance is 5 to 50% by weight, and preferably 10 to 30% by weight. The ultrafine particles can be inhibited by the addition of the dispersing agent, and the time stability is improved. Nonionic and anionic Both the surfactant and the water-soluble resin can be used as a dispersing agent. The water-soluble resin includes a synthetic water-soluble resin such as polyvinyl alcohol, polyacrylic acid, acrylic copolymer, maleic acid resin, polyvinylpyrrolidone, polyethylene oxide, water-soluble. A water-dispersible emulsion of an acrylic resin, a water-soluble styrene-acrylic resin, an acrylic resin, an alkyd resin, a vinyl resin, a polyester resin, a styrene resin, a maleic acid resin, and a urethane resin. It is preferably previously converted into an aqueous dispersion (slurry) by a dispersing machine and then blended. The coloring agent used in the ink composition of the present invention includes a pigment and/or a water-soluble dye. The kind of the pigment is not particularly limited. And has so far been used in water • 10-(7) 1328027 Ink pigment 吖 言, CI (C. 6B (and C granule fake tree water soluble direct 51 and direct ' 81, and straight 106 | Inorganic and organic pigments of the composition of the black water can be used. Inorganic pigments include carbon black and metal powder, etc. Organic pigments include azo deep red, insoluble azo pigment, stomach $ @ M, 酞花青Pigments, enamel and perinone pigments, awake pigments, mouth quinone pigments, dye crimson, nitro pigments and nitroso pigments, etc. Specifically, users can use phthalocyanine blue (CI 74 1 60), Euro% 胄 green £ (74260), Hansa Yellow 3G (CI 11670), diazo yellow GR I · 2 1 1 0 0 ), permanent red 4 R (C · I · 1 2 3 3 5 ), bright carmine CI 15850) D Kui Uf Blush (CI 46500). A plastic pigment composed of styrene-based resin particles can also be used. Further, the hollow resin particles having pores therein can be used as a white pigment or as a grease which can be used as a multicolor after being colored with a dye. Direct dyes, acid dyes, food dyes and basic dyes can be used as the dye. Examples of direct dyes are described below. It includes CI Direct Black I?, Black 19, Direct Black 22, Direct Black 32, Direct Black 38, Direct Black Direct Black 71, ci·Direct Yellow 4, Direct Yellow 26, Direct Yellow 44 and Yellow 50, Direct Red 1' Direct red 4, direct red 23, direct red 31 red 3 7 'direct red 3 9 , direct red 7 5, direct red 8 〇, direct red direct red 83, direct red 22 5, direct red 226 and direct red 227 Connect blue direct blue I5, direct blue 71, direct blue 86, direct blue per direct blue 1 1 9 Examples of acid dyes are described below. It includes CI Acid Black 1, Acid 2, Acid Black 24, Acid Black 26, Acid Black 31, Acid Black 52, -11 - (8) (8) 1328027 Acid Black 107, Acid Black 109, Acid Black 110, Acid Black 119 and acid black 154, CI acid yellow 7, acid yellow 17' acid yellow 19, acid yellow 23, acid yellow 25, acid yellow 29, acid yellow 38, acid yellow 42, acid yellow 49, acid yellow 61, acid yellow 72 Acid yellow 78, acid yellow 11 〇, acid yellow 127, acid yellow 135, acid yellow 141 and acid yellow 142, CI acid red 8 'acid red 9, acid red 14, acid red 18, acid red 2 6 , acid Red 2 7 , Acid Red 3 5 , Acid Red 3 7 , Acid Red 5 1 , Acid Red 52 , Acid Red 57 , Acid Red 82 , Acid Red 87 , Acid Red 92 , Acid Red 94 'Acid Red 1 1 5 'Acid Red 129, acid red 13 1 , acid red 186, acid red 2 4 9 , acid red 2 5 4 , acid red 2 6 5 and acid red 2 7 6 , (: 1.1 acid purple 18 and acid purple 17 , CI Acid Blue 1, Acid Blue 7, Acid Blue 9, Acid Blue 22, Acid Blue 23, Acid Blue 25, Acid Blue 40, Acid Blue 4 1 , Acid Blue 4 3, Acid Blue 6 2 'Acid Blue 7 8 Acid blue 83 Acid Blue 90, Acid Blue 93, Acid Blue 103, Acid Blue ι12, Acid Blue 1 1 3 and Acid Blue 1 5 8 and C. I _ Acid Green 3, Acid Green 9, Acid Green 16, Acid Green 25 and Acidity Green 27 » Most food dyes are included in direct dyes or acid dyes, and an example not included in them is CI Food Yellow 3. Examples of basic dyes are described below. They include CI alkaline jaundice, test Sexual yellow 2 and test yellow 21, CI test implant 2 'experimental lamp 14 and test sandalwood 3 2, C · I _ alkaline red 1, alkaline red 2, alkaline red 9 and alkaline red! 4 , c丄 basic brown 12 and CI basic black 2 and basic black 8» The above colorants may be used singly or in combination of two or more thereof, and the content of the total ink composition is usually 〇·5 to 30 by weight. %, and -12 - (9) (9) 1328027 is preferably from 1 to 15% by weight. If the colorant content in the ink composition exceeds 30% by weight and is stored for a long period of time, the pigment may flocculate or dye Will precipitate and make the nib clog, so it can't be written. If the content is less than 0.5% by weight, the coloring effect is poor or the line color is unclear. This is not suitable. When pigments are used as colorants, dispersants must be used. The role of the dispersant is to adsorb on the surface of the pigment to enhance the affinity of the pigment for water and to stably disperse the pigment in water, nonionic and anionic interfaces. The active agent and the water-soluble resin are often used as a dispersing agent. Water-soluble polymers are preferred. In order to increase the viscosity of the ink to suppress the sedimentation of the ultrafine particles, it is effective and preferable to add a small amount of a thickener to the aqueous ink composition of the present invention. The thickener which can be added is preferably a shear-diluting agent which provides a plasticity which controls ink discharge properties and suppresses fine particle sedimentation, and a known compound can be used as a thickener. Preferred are, for example, at least one compound selected from the group consisting of synthetic polymers, natural rubber, cellulose, and polysaccharides. Specifically, it includes water-soluble gum arabic, succinoglycan 'welan gum, Tragacons gum, ancient gum, locust bean gum, alginic acid, Carrageenan, gelatin, casein, fulvic acid gum, dextran, methyl cellulose, ethyl cellulose, hydroxyethyl cellulose, residual methyl cellulose ' sodium glycolate starch, propylene glycol algae Copolymerization of acid ester, polyvinyl alcohol, polyethyl ketone oxime, polyethylidene methyl acid, sodium polyacrylate, residual vinyl polymer, polyethylene oxide, vinyl acetate and polyvinylpyrrolidone A salt of a cross-linked acrylic polymer and a styrene-acrylic acid copolymer-13-(10) (10) 1328027. The content based on the total amount of the ink composition (in terms of solid content) is preferably from 0.1 to 0.6% by weight, and more preferably from 0. 1 to 0.4% by weight. A P Η controlling agent, a rust preventive, a preservative, a bactericide, and a lubricant may be added to the ink composition of the present invention as needed. Lubricants include nonionic compounds such as fatty acid esters of polyhydric alcohols, high carbon fatty acid esters of sugars, polyoxyalkylene high carbon fatty acid esters and alkyl phosphates, anionic compounds such as high carbon fatty decylamine alkyl sulfonic acids. Salts and alkylaryl sulfonates, as well as surface treatment agents for pigments, derivatives of polyalkylene glycols, fluorine-based surfactants, and fluorenone modified with polyethers. The rust inhibitor includes benzotriazole, tolyltriazole, cyclohexylammonium nitrite, and soap essence, and the pH controlling agent includes ammonia, urea, triethanolamine, amine methylpropanol, and sodium hydroxide. Preservatives or bactericides include guanidine, sodium omadine, sodium benzoate and benzimidazolyl compounds. The aqueous ink composition of the present invention can be obtained by a conventional method, for example, by applying a predetermined amount of the above individual components to a mixer (for example, a homomixer) and a dispersing machine for stirring and mixing. Further, the coarse particles contained in the ink composition may be removed by filtration or centrifugation as needed. Although the mechanism of suppressing the wear of the outer cover of the ball from ultrafine particles containing alumina, titania, yttria, tantalum carbide and tungsten carbide has not been confirmed, in the fine-grain pen, the ultrafine particles of less than 0.1 micrometer are used for writing. The ball rotates and releases the pressure generated by the ink and is deeply buried in the outer cover of the ball. Therefore, the surface hardness of the outer cover is increased to suppress the wear of the outer cover caused by the rotation of the ball. The above effect does not interfere with the rotation of the sphere, because at the time of writing, the -14 - (11) (11) 1328027 ultrafine particles are evenly distributed in the ink between the sphere and the outer cover. Therefore, it is generally considered that the aqueous ink composition of the present invention can stably suppress the abrasion of the outer cover of the ball and provide a good writing feeling without impairing the scribing property. EXAMPLES Hereinafter, the present invention will be more specifically described with reference to examples, but the present invention is by no means limited to these examples. Examples 1 to 9 and Comparative Examples 1 to 9 The aqueous ink compositions of Examples 1 to 9 and Comparative Examples 1 to 9 were prepared in the form of a homogeneous solution which was subjected to the following components 1 to 1 by means of a stirrer. The amount (% by weight) shown in 1 was obtained by blending. Ι-a. Colorant (Pigment): Carbon Black Ib. Colorant (Dye): Red No. 105 2 - a · Provides a reagent to reduce shear properties: Yellow acid gum 2 - b . Provides reagents that reduce shear properties: Crosslinked polyacrylic acid 3-a. Water-soluble organic solvent: glycerol 3-b. Water-soluble organic solvent: propylene glycol 4. Lubricant: phosphate alkyl ether 5. Rust inhibitor: benzotriazole 6. Preservative: 1:2·Benzoisothiazolin-3-one 7. p ΗControl agent: triethanolamine 8-a. Alumina: main particle size 0.033 μm 8-b. Alumina: primary particle size 0.013 μm-15- ( 12) (12) 1328027 8- c. Alumina: main particle size 0.7 μm 9- a. titanium oxide: main particle size 0.05 μm 9-b. titanium oxide · · main particle size 〇 〇 3 μm 9-c. Titanium oxide: main particle size 0.27 μm 10. Carbide carbide: main particle size 0.04 μm 11. Tungsten carbide: main particle size 0 · 0 6 μm 12. Water-soluble resin: styrene-acrylate copolymer 1 3. Refined water viscosity The measurement was carried out using a cone-and-plate type rotational viscometer, that is, the viscosity tanning system was measured by a cone-plate type rotational viscometer EMD manufactured by Tokimec Inc. at 25 ° C and an ST rotor rotation speed of 1 rpm (l° 34, R24 corn). Got it. A ballpoint pen tip having spheres having different spherical diameters was placed in a small tube (a tube made of pp and having an inner diameter of 3.4 mm) and a connecting member made of polypropylene, and each was placed in a manufacturing unit manufactured by Mitsubishi Pencil Co., Ltd. In UM-151, the aqueous ink composition and the ink accompanying product prepared in the examples and the comparative examples were charged therein and subjected to centrifugation (500 G, 5 minutes) to defoam. It is then assembled into a ballpoint pen and subjected to various writing tests as shown below. The writing test was carried out in the following manner, and all evaluation tests were carried out with five ball pens. 1) Anti-wear test: A spiral writing of 1 〇〇〇m (writing end point) was performed with a writing tester and evaluated according to the following criteria: Writing conditions: 100 gf, writing angle: 75 degrees, writing speed: 4.5 mm/min - 16 - (13) (13) 1328027 ◎: All samples are free of problems and can be written 〇: slightly lack of ink but can be written to the end of writing △: lack of ink but can be written to the end of writing ▲: at least one pen because of ink The amount is reduced and the scribe line becomes thinner and cannot be written. X: All samples become unwritten during writing because of significant wear 2) Writing sensation test: The writing sensation is evaluated by the smooth feeling of writing and judged according to the following criteria. : ◎: Very smooth 〇: smooth △: There is a scratching feeling X: Bad 3) Scribe nature: The scribing is performed by a writing test machine with a spiral writing of 200 m and evaluated according to the following criteria: Writing conditions: 100 gf, Writing angle: 75 degrees, writing speed: 4.5 mm / min ◎: Good 〇: slightly different shades but good △: slightly broken ink ▲: broken ink and slightly difference in direction X: the whole line has a difference in direction -17 - (14) (14) 1328027 4 Centrifugal resistance: Centrifuge the pen (800 G' for 0 minutes) using a centrifugal separator, and evaluate the writing properties of a circle with a diameter of about 1.5 cm according to the following criteria: ◎: Write from the beginning, without any The problem is: there is a slight lack of ink at the beginning but it is restored within five times of rounding. △: There is a lack of ink in the circle for five to ten times, but then X is restored: there are still ink shortages after ten or more rounding. Time stability of the writing nature: the pen tip is turned down and allowed to stand at 50 t: for two weeks, and the time stability of the writing property is evaluated for the circle and its frequency according to the following criteria: ◎: writing can be started from the beginning, No problem 〇: A slight lack of ink at the beginning but recovered within five rounds of △: There is a lack of ink in the circle for 5 to 20 times, but then X is restored: there are still inks missing after 20 or more rounding The phenomenon or the inability to write the results of the 5 evaluations of the examples 1 to 9 are not in Table 1 and the evaluation results of the comparative examples 1 to 9 are shown in Table 2. -18- (15) 1328027 Example 〇ssooo 〇〇m — ddd ^ (Ν ο 0.5 more 51 00 ΓΊ 〇〇 ◎ 0 〇〇〇 (N 〇 OC inch ooo oo α N ood 01 ^ t; Ο 0.5 Μ CS Ro ◎ <3 0 ◎ ◎ 〇〇 (N 〇 VO ΚΓ) (N 〇oo S 2 5 ^ 5 0.3 S 2125 ◎ <1 〇 ◎ ◎ 〇〇 <N 〇VO os οο 0.5 remaining fi v 〇 κ 〇 〇 ◎ ◎ ◎ ◎ wn ο ΚΠ κη ΓΊ 〇 oo rn ο 0.5 more fi < η Vi 卜 © © οο cs ο rn rn 〇 oo S25- 0.5 balance οο JS ◎ ◎ 〇 ◎ ◎ ( Ν Ο m in 对 对 o (N 00 n - 0 0 001 ο 0.5 balance ο 5 ◎ <] ◎ ◎ ◎ 寸 · ο CN Ό O oo 0.3 balance οο κτ) οο ◎ ◎ 〇 ◎ ◎ οο ο ΓΜ os S Ο 0.5 balance κ κη (Ν ◎ ◎ ◎ ◎ ◎ οο ο particle size (micron) mmm - Γ -» Ρ <=> d ο ο 0.05 0.03 0.27 g Ο g ο cc Jp Πί JO <N OJ . X) rA γΛ to un v〇卜 cz Ο ι ι » οο oc οο C3 JD ϋ 1 1 1 Ον Ον Ον Ο II (Ν ΓΊ Ε ο. Colorant thickening Water-soluble solvent etchant rust inhibitor preservative pH control agent vaporized aluminum fine grain ^ titanium 丨 grain 碳 fine grain tungsten carbide fine grain water-soluble resin slightly water viscosity (mPa-s) anti-wear ^ writing sense Na linear 玎 anti-centrifugal AS κ 冏 冏 stability ball diameter (3⁄4 m) -19- (17) (17) 1328027 From the evaluation results of Table 1 and Table 2, it can be found that the composition of the aqueous ink conforms to the conditions of the present invention 5毫米之间。 The object in the ball diameter of 〇. 5 mm or less in the fine-grain pen has excellent writing characteristics and anti-wear. On the other hand, the aqueous ink composition does not meet the conditions of the present invention at a ball diameter of 〇. 5 mm Or the following fine-grain pen has poor writing characteristics and abrasion resistance. Specifically, the abrasion resistance is in Comparative Example 1 'Comparative Example 8 and Comparative Example 9 (in which the ultrafine particles according to the present invention are not added) Comparative Example 3, in which the amount of the ultrafine particles added was lower than the lower limit of the present invention, was extremely poor. Further, it was found that in Comparative Example 2, Comparative Example 5, Comparative Example 6, and Comparative Example 7 in which the primary particle diameter of the fine particles to be added was 0.1 μm or more, the abrasion resistance did not reach a satisfactory level and various Efficacy (such as writing sensation, anti-centrifugality, and temporal stability of writing properties) deteriorates, and this trend becomes more pronounced as the pen's sphere becomes smaller. Further, the writing feeling was significantly deteriorated in Comparative Example 4, wherein the amount of fine particles added exceeded the upper limit of the present invention. It is therefore apparent that the aqueous ink composition falling outside the scope of the present invention does not solve the problems of the present invention. Industrial Applicability The aqueous ink composition of the present invention can be used for a fine-grain pen, especially a fine-grain pen having a ball diameter of 0.5 mm or less.

Claims (1)

1328027 #年"月沐日修(吏)本本94 11. 28 X. Application for patent scope Attachment: Patent application No. 93132314 Revision of Chinese patent application scope Amendment of November 28, 1994 of the Republic of China 1. A fine-grain pen of 0.4 mm or less, characterized in that it is filled with an aqueous ink composition comprising at least one or two ink compositions containing at least water, a colorant and a water-soluble solvent. The above-mentioned ultrafine particles selected from the group consisting of alumina, titania, cerium oxide, cerium carbide and tungsten carbide and having an average particle diameter of less than 0.1 μm are blended, wherein the ultrafine particles are blended in an amount of 0.002 to 2 based on the ink composition. % by weight, and the aqueous ink composition has a viscosity of 100 to 1000 mPa-s (25 ° C) measured at 1 rpm using a cone and plate type rotational viscometer (1° 34' R24 cone). .