Aqueous ink composition

Abstract

To provide an aqueous ink composition that is charged into writing tools or applicators such as marking pens or brush pens, exhibits excellent pigment fixation performance, and ensures excellent recovery of pen tips, brush hairs, and application parts.SOLUTION: An aqueous ink composition comprises titanium oxide, an ethylene-vinyl acetate resin emulsion having an elongation at 23°C of 400% or more and 1000% or less, a polycarbonate-based urethane resin emulsion, and water.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an aqueous ink composition which is filled into a writing instrument or applicator such as a marking pen or brush pen and has excellent pigment fixation and good restoration of the pen tip, brush tip and coated area. [Background technology]

[0002] Conventionally, in aqueous ink compositions for obtaining writing with hiding power or writing with brilliance, at least a white pigment such as titanium oxide, or a reflective colorant having brilliance such as a pearl pigment or a metal powder pigment has been used as a pigment.

[0003] For example, Patent Document 1 discloses an aqueous pigment composition that contains at least titanium oxide having an isoelectric point higher than the pH of the ink, resin particles, an acrylic resin emulsion as a binder, and water, as an aqueous ink that uses titanium oxide and has good redispersibility.

[0004] Furthermore, Patent Document 2 discloses an aqueous ink composition having excellent fixability of handwriting, which contains pigment particles, an extender, an aggregation dispersant, an aggregation control agent, an acrylic emulsion as a self-crosslinking resin emulsion, polyolefin resin particles, and a solvent. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 11-343443 [Patent Document 2] JP 2017-115084 A Summary of the Invention [Problem to be solved by the invention]

[0006] It is known that acrylic resin emulsions are used in inks using large particle size pigments such as reflective colorants with brilliance such as titanium oxide, pearl pigments, and metal powder pigments to provide hiding power and gloss, in order to improve redispersibility and provide fixability, but acrylic resin emulsions with excellent fixability are prone to increase in viscosity due to slight water evaporation, and when they dry due to contact with air, a coating is formed, which deteriorates the drying resistance of the pen tip, and once the pen tip dries, it cannot be restored. In particular, in pen tips that extract ink containing titanium oxide as a white pigment from narrow and complex gaps in a fiber bundle with high liquid retention used in felt-tip pens, marking pens, brush pens, felt-tip pens, etc., even a slight increase in the viscosity of the ink slows down the flow of the ink, making it prone to problems such as smearing, and if the ink does not dry out and restores to its original state, it is prone to problems such as the ink becoming unusable even if there is a sufficient amount of ink remaining.

[0007] The present invention aims to provide an aqueous ink composition which, even if it is an ink using a pigment that imparts hiding power, has excellent fixation of handwriting, and can be restored even if the pen tip or application part dries out, even when used with a writing instrument equipped with a brush-type application part. [Means for solving the problem]

[0008] The gist of the present invention is an aqueous ink composition comprising at least titanium oxide as a white pigment, an ethylene-vinyl acetate resin emulsion having an elongation of 400% or more and 1000% or less at 23°C, a polycarbonate-based urethane resin emulsion, and water. Effect of the Invention

[0009] The water-based ink composition of the present invention is filled into a writing instrument or applicator such as a marking pen or a brush pen and used. By using an ethylene-vinyl acetate resin emulsion having an elongation of 400% to 1000% at 23°C in combination with a polycarbonate-based urethane resin emulsion as a fixing agent, it is possible to obtain handwriting that is resistant to rubbing and has good fixing properties even with a pigment such as titanium oxide, which is difficult to fix. Furthermore, compared to acrylic resin emulsions, the viscosity of the ink is less likely to increase when the water content of the ink is reduced, and the emulsion is less likely to be destroyed, so that even if the pen tip dries out and becomes smudged, the ink viscosity of the pen tip can be restored to a low viscosity by sealing with a cap by the ink in the ink storage section. [Brief description of the drawings]

[0010] [Figure 1] A longitudinal sectional view of the applicator 1 DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] The titanium oxide used in the water-based ink composition of the present invention is a white colorant with hiding properties, and by adjusting the particle size and amount added, or by using it in combination with other colorants, it is possible to form handwriting with color development that maintains hiding properties even on dark paper, or to form handwriting with characteristic colors such as pastel colors. There is no particular limitation on the titanium oxide that can be used, so long as it is a conventionally known titanium oxide. Specific examples of titanium oxide include SR-1, R-3L, R-5N, R-7E, R-24, R-61N, R-62N, R-310, R-650, D-918, FTR-700, and TCR-52 (all manufactured by Sakai Chemical Industry Co., Ltd.), Typek R-550, Typek R-580, Typek R-630, Typek R-670, Typek R-680, Typek R-780, Typek R-780-2, Typek R-820, Typek R-830, Typek R-930, Typek R-980, Typek PR-690, Typek PF-691, Typek PF-711, Typek PF-736, Typek PF-737, Typek PF-739, PF-740, PC-3, S-305, CR-50, CR-50-2, CR-57, CR-58, CR-58-2, CR-Super70, CR-80, CR-85, CR-90, CR-90-2, CR-93, CR-97, A-100, A-220 (all manufactured by Ishihara Sangyo Kaisha), Kronos KR-270, KR-310, KR-380, KR-380-N, KR-480, KA-10, KA-15, KA-20, KA-30 (all manufactured by Titanium Kogyo Co., Ltd.), TITANIX JR-300, JR-301, JR-403, JR-405, JR-600A, JR603, JR-605, JR-600E, JR-603, JR -800, JR-801, JR-805, JR-806, JR-906, JR-701, JRNC, JR, JA-1, JA-C, JA-3 (the above, Examples of such products include TA-100, TA-200, TA-300, TA-400, TR-600, TR-700, TR-840, and TR-900 (all manufactured by Fuji Titanium Industry Co., Ltd.), and Typure R-700, R-706, R-900, R-901, and R-902 (all manufactured by DuPont Japan Limited).

[0012] In order to increase the dispersion efficiency of the titanium oxide particles, commercially available water-dispersible titanium oxide particles are preferably used because they are easier to handle and more productive. Specific examples of water-dispersed titanium oxide particles using an anionic water-soluble resin dispersant include FUJI SP WHITE 1142 (acrylic water-soluble resin dispersion, solid content 31.0 to 45.0%), FUJI SP WHITE 1193 (acrylic water-soluble resin dispersion, solid content 45.0 to 55.0%) (all manufactured by Fuji Pigment Co., Ltd.), NAF 5002 White (acrylic water-soluble resin dispersion, solid content 65%), and AF White E-3D (acrylic water-soluble resin dispersion, solid content 64%) (all manufactured by Dainichiseika Color & Chemicals Co., Ltd.). Examples of water-dispersed titanium oxide particles using a cationic water-soluble resin dispersant include FUJI SP WHITE 1209 (allyl amine water-soluble resin dispersion, solid content 45.0 to 55.0%) (all manufactured by Fuji Pigment Co., Ltd.). Other examples include FUJI SP WHITE 143, FUJI SP WHITE 383, FUJI SP WHITE 552, FUJI SP WHITE 553, FUJI SP WHITE 791, and FUJI SP WHITE 1186 (all manufactured by Fuji Pigment Co., Ltd.).

[0013] As a dispersant for dispersing titanium oxide, a conventionally known dispersant can be appropriately used. Specifically, a surfactant, a water-soluble resin, a resin emulsion, etc. are preferably used, and these dispersants can also be used in combination. Examples of anionic surfactants that can be used include alkylated sulfonates of higher fatty acid amides, alkyl aryl sulfonates, and the like, specifically, alkyl sulfates, polyoxyethylene alkyl ether sulfates, N-acyl amino acid salts, N-acyl methyl taurine salts, polyoxyethylene alkyl ether acetates, alkyl phosphates, and polyoxyethylene alkyl ether phosphates.Among them, polycarboxylic acid type surfactants such as Demol EP, Homogenol L-18, Poise 520, and 530 (all manufactured by Kao Corporation), naphthalenesulfonic acid formalin condensate type surfactants such as Demol N (manufactured by Kao Corporation), Sannol LMT-1430, Sannol TD-3130 (all manufactured by Lion Corporation), Emeral 20C, Emeral 270J, Emeral 20CM, Emeral D-3-D, Emeral D-4- Polyoxyethylene alkyl ether sulfates such as Emeral 20T, Latemul E-118B, Latemul E-150, and Latemul WX (all manufactured by Kao Corporation), alkyl sulfates such as Sannol EH-1145M, Sannol LM-1130, and Sannol LM-1140T (all manufactured by Lion Corporation), and Alscope LN-90PW, Alscope LS-40T, Alscope LS-30, and Alscope LS -25B, Alscope NS-230, Alscope TH-330K, Alscope TH-370N, Alscope DA-330S, Alscope N-335T, Alscope A-225B (all manufactured by Toho Chemical Industry Co., Ltd.), Emeral 0, Emeral 0S, Emeral 10S, Emeral 2FG, Emeral 2F-30, Emeral TD (all manufactured by Kao Corporation), and other higher alkyl sulfates, such as Lipon LS-250, Lipon LH- Sodium alkylbenzene sulfonates such as Liporan PJ-400CJ, Liporan LB-440, Liporan LJ-441, K Liporan PJ-400C, Liporan LB-840, Liporan PB-800CJ (all manufactured by Lion Corporation); and alkylbenzene sulfonates such as Lunox S-40TD (all manufactured by Toho Chemical Industry Co., Ltd.), Neopelex G-15, Neopelex G-25, Neopelex G-65, Neopelex GS (all manufactured by Kao Corporation) can be preferably used. Examples of nonionic surfactants include polyoxyalkylene higher fatty acid esters, higher fatty acid esters of polyhydric alcohols and derivatives thereof, and higher fatty acid esters of sugars, specifically, fatty acid esters of glycerin, propylene glycol fatty acid esters, pentaerythritol fatty acid esters, polyoxyethylene sorbitan fatty acid esters, polyoxyethylene sorbit fatty acid esters, polyoxyethylene glycerin fatty acid esters, polyethylene glycol fatty acid esters, polyoxyethylene alkyl ethers, polyoxyethylene styrenated phenyl ethers, polyoxyethylene phytosterols, polyoxyethylene polyoxypropylene alkyl ethers, and polyoxyethylene alkyl phenyl ethers. ether, polyoxyethylene castor oil, polyoxyethylene lanolin, polyoxyethylene lanolin alcohol, polyoxyethylene alkylamine, polyoxyethylene fatty acid amide, polyoxyethylene alkylphenyl formaldehyde condensate, etc. can be used. Among them, acetylene glycol type surfactants such as Surfynol TG and Surfynol 104E (both manufactured by Nissin Chemical Industry Co., Ltd.), polyoxyethylene alkyl ether type surfactants such as Pegnol O-6 (both manufactured by Toho Chemical Industry Co., Ltd.), Noigen P, Noigen ET (both manufactured by Daiichi Kogyo Seiyaku Co., Ltd.), polyoxyethylene alkyl phenyl ether type surfactants such as Nonal 210 and Noigen 212 (both manufactured by Toho Chemical Industry Co., Ltd.), NIKKOL Polyoxyethylene sorbitan fatty acid esters such as TL-10, NIKKOL TP-10, NIKKOL TO-10M, NIKKOL TO-10, NIKKOL TI-10 (all manufactured by Nikko Chemicals Co., Ltd.), RHEODOR TW-L120, RHEODOR TW-O120V, RHEODOR Super TW-L120, RHEODOR TW-P120, RHEODOR WO120 (all manufactured by Kao Corporation), polyoxyethylene glycol fatty acid esters such as NIKKOL MYS-25, NIKKOL MYS-45, NIKKOL MYS-55, NIKKOL CDS-600P (all manufactured by Nikko Chemicals Co., Ltd.), EMANON 3199B, EMANON 3299V, EMANON 3299RV (all manufactured by Kao Corporation), NIKKOL HCO-80, NIKKOLPolyoxyethylene water-added hydrogenated castor oil such as HCO-100 (all manufactured by Nikko Chemicals Co., Ltd.), Emulgen 108, Emulgen 120, Emulgen 123P, Emulgen 130K, Emulgen 147, Emulgen 150, Emulgen 210P, Emulgen 220, Emulgen 350, Emulgen 430, Emulgen 4085, Emulgen 2025G (all manufactured by Kao Corporation), NIKKOL PBC-34, NIKKOL PBC-44, NIKKOL BL-21, NIKKOL BL-25, NIKKOL BC-15, NIKKOL BC-20, NIKKOL BC-23, NIKKOL BC-25, NIKKOL BC-30, NIKKOL BC-40, NIKKOL BS-20, NIKKOL BO-15V, NIKKOL Polyoxyalkylene alkyl ethers such as BO-20V, NIKKOL BO-50V, NIKKOL BB-20, NIKKOL BB-30, and NIKKOL BD-10 (all manufactured by Nikko Chemicals Co., Ltd.), RYOTO Sugar Ester S-1570, RYOTO Sugar Ester S-1670, RYOTO Sugar Ester P-1570, RYOTO Sugar Ester P-1670, RYOTO Sugar Ester M-1695, RYOTO Sugar Ester O-1570, and RYOTO Sugar Ester Sucrose fatty acid esters such as Pluronic L-1695 (all manufactured by Mitsubishi Chemical Foods Corporation), Pluronic L10, Pluronic L31, Pluronic L61, Pluronic L62, Pluronic 10R5, Pluronic 17R2, Pluronic 25R2 (all manufactured by BASF Japan Kao Corporation), ADEKA Pluronic L-23, ADEKA Pluronic L-31, ADEKA Pluronic L-44, ADEKA Pluronic L-61, ADEKA Pluronic L-62, ADEKA Pluronic L-64, ADEKA Pluronic L-71, ADEKA Pluronic L-72, ADEKA Pluronic L-101, ADEKA Pluronic L-121, ADEKA Pluronic P-84, ADEKA Pluronic P-85, ADEKA Pluronic P-103, ADEKA Pluronic F-68, ADEKA Pluronic F-88, ADEKA PluronicPoly(oxyethylene) poly(oxypropylene) block copolymers such as F-108 (all manufactured by ADEKA Corporation) can also be preferably used, and polyoxyethylene distyrenated phenyl ether surfactants such as Emulgen A-60, Emulgen A-90, and Emulgen B-66 (all manufactured by Kao Corporation) are particularly suitable as surfactants that are less likely to cause color sinking due to their low foaming properties, excellent pigment dispersion stability, and low penetrability. Examples of cationic surfactants include alkylamine acetate, alkyltrimethylammonium chloride, alkyltrimethylammonium bromide, distearyldimethylammonium chloride, alkylbenzyldimethylammonium chloride, alkyldimethylbenzylammonium chloride, fatty acid amine salts, quaternary ammonium salts, sulfonium salts, and phosphonium salts. These surfactants can be used alone or in combination. They can also be used in combination with a water-soluble resin dispersant that disperses the pigment, and the amount of the surfactant used is preferably 0.01 to 20% by weight based on the total amount of the aqueous pigment ink. In order to maintain suitable dispersibility of the pigment, the amount is preferably 0.1 to 1% by weight.

[0014] Examples of water-soluble resin dispersants and resin emulsion dispersants include anionic polymers obtained by polymerizing monomers selected from the group consisting of unsaturated carboxylic acids such as acrylic acid, methacrylic acid, maleic acid, and itaconic acid, or their alkyl esters, styrene, acrylonitrile, urethane, and vinyl acetate, and copolymers of two or more of the above monomers, which are used in the form of alkali metal salts, ammonium salts, or amine salts; cationic water-soluble resin dispersions obtained by polymerizing cationic monomers such as polyamines and polyallylamine; amphoteric water-soluble resin dispersants obtained by polymerizing monomers having cationic and anionic moieties, which are polymers having both properties; natural resins such as gum arabic and rosin, and their derivatives; hydroxycellulose and its derivatives; polyvinyl alcohol; and polyvinylpyrrolidone. In particular, water-soluble salts of copolymers of styrene and / or α-methylstyrene with acrylic acid and / or methacrylic acid are preferred because of their excellent pigment dispersibility. Commercially available anionic polymers include FK-64S, FK-471, FK-474, FK-285, FK-6100, and Mowinyl 952B (all manufactured by Japan Coating Resins Co., Ltd.), Vinisol 1637, 1117, 1008, 1606A, 911, Acrit WEM-202U, WEM-321U, and WBR-016U (all manufactured by Daido Chemical Industry Co., Ltd.), Joncryl HPD-196, HPD-96J, 7100, 711, PDX-7341, and PDX Examples of such water-soluble resins and resin emulsions include PDX-7787, PDX-7734, PDX-7687, PDX-352D, PDX-7164, PDX-7430, PDX-52J, PDX-57J, PDX-60J, PDX-61J, and PDX-62 (all manufactured by BASF Japan Co., Ltd.), Evafanol HA-50C, HA170, Neosticker 400, and 700 (all manufactured by Nicca Chemical Co., Ltd.), Ucoat UWS-145, Parmarin UA-200 (all manufactured by Sanyo Chemical Industries, Ltd.), Seiko PMC Co., Ltd.'s Hi-Loss series, Toagosei Co., Ltd.'s ARUFON, and Nittobo Medical Co., Ltd.'s PAA series and PAS series as cationic polymers and amphoteric polymers. These water-soluble resins and resin emulsions can be used alone or in combination. A surfactant that disperses the pigment may also be used in combination, and the amount of the water-soluble resin or resin emulsion used is preferably 1 to 50% by weight in terms of solid content based on the total amount of the water-based pigment ink. In particular, it is preferable to disperse titanium dioxide in a cationic surfactant or water-soluble resin, and disperse other color pigments in an anionic surfactant to make an ink, as this improves color separation, pigment stability over time, and redispersibility.

[0015] The content of titanium oxide particles in the ink composition is suitably 5.0% by weight or more and 40.0% by weight or less, based on the total amount of the ink composition. If the content is more than 5.0% by weight and less than 25.0% by weight, high hiding power and clear, clean handwriting can be obtained, and this is more preferable.

[0016] If the average particle size of titanium oxide in the ink composition is 0.1 μm or more, the transmission of light can be suppressed, and light is easily reflected on the surface of titanium oxide particles, so that white color is easily developed. Also, if the average particle size of titanium oxide is 0.2 μm or more and 1.0 μm or less, and especially if the average particle size is 0.3 μm or more and 0.7 μm or less, the dispersion stability of the ink alone is good, and the handwriting has a suitable hiding power, good color development, and clarity, and the handwriting does not fade, which is optimal.

[0017] The oil absorption and water absorption of titanium oxide particles vary depending on the blending ratio of the surface treatment agent used for the surface treatment of titanium oxide particles. For example, when the surface treatment of titanium oxide particles is performed using SiO2 and Al2O3 as surface treatment agents, if there is more Al2O3 than SiO2 on the surface of the titanium oxide particles, the oil absorption of the titanium oxide particles will be small and the water absorption will be large. On the other hand, if there is more SiO2 than Al2O3 on the surface of the titanium oxide particles, the oil absorption of the titanium oxide particles will be large and the water absorption will be small. The oil absorption of titanium oxide particles in the ink composition is preferably 29g / 100g or more and 35g / 100g or less. Titanium oxide particles with an oil absorption of 29g / 100g or more and 35g / 100g or less have excellent adsorption properties for dispersants such as surfactants and resin emulsions, and improve dispersibility. Even when used in combination with resin particles, they easily form complexes through interactions with other resin particles, etc. while maintaining a moderate distance between the particles, and have excellent dispersion stability, and especially in caking, the sediment is less likely to form a hard cake, improving redispersibility. These titanium oxides or dispersions thereof may be used alone or in combination of two or more kinds.

[0018] As a coloring agent to be used in combination with titanium oxide for color matching, a conventionally known dye or pigment can be used. As the dye, direct dyes, acid dyes, basic dyes, etc., which are used in conventional water-based inks and oil-based inks, can be used. Specifically, Japanol Fast Black D Concentrate (CI Direct Black 17), Water Black 100L (CI Direct Black 19), Water Black L-200 (CI Direct Black 19), Direct Fast Black B (CI Direct Black 22), Direct Fast Black AB (CI Direct Black 32), Direct Deep Black EX (CI Direct Black 38), Direct Fast Black Concentrate (CI Direct Black 51), Kayalas Spraglay VGN (CI Direct Black 71), Kayalas Direct Brilliant Yellow G (CI Direct Yellow 4), Direct Fast Yellow 5GL (CI Direct Yellow 26), Aizen Primula Yellow GCLH (CI Direct Yellow 44), Direct Fast Yellow R (CI Direct Yellow 50), Aizen Direct Fast Red FH (CI Direct Red 1), Nippon Fast Scarlet GSX (CI Direct Red 4), Direct Fast Scarlet 4BS (CI Direct Red 23), Aizen Direct Rhoduline BH (CI Direct Red 31), Direct Scarlet B (CI Direct Red 37), Kayak Direct Scarlet 3B (CI Direct Red 39), Aizen Primula Pink 2 BLH (CI Direct Red 75), Sumi Light Red F3B (CI Direct Red 80), Aizen Primula Red 4 BH (CI Direct Red 81), Kayalas Spralubin BL (CI Direct Red 83), Kayalas Light Red F5G ( CI Direct Red 225), Kayalas Light Red F5B (CI Direct Red 226), Kayalas Light Rose FR (CI Direct Red 227), Direct Sky Blue 6B (CI Direct Blue 1), Direct Sky Blue 5B (CI Direct Blue 15), Sumilight Sprat Blue BRR Conc (CI Direct Blue 71), Daibogen Turquoise Blue S (CI Direct Blue 86), Water Blue #3 (CI Direct Blue 86), Kayalas Turquoise Blue GL (CIDirect Blue 86), Kayalas Splat Blue FF2GL (CI Direct Blue 106), Kayalas Splat Turquoise Blue FBL (CI Direct Blue 199), and other direct dyes, Acid Blue Black 10B (CI Acid Black 1), Nigrosine (CI Acid Black 2), Suminol Milling Black 8BX (CI Acid Black 24), Kayanol Milling Black VLG (CI Acid Black 26), Suminol Fast Black BR ​​Conc (CI Acid Black 31), Mitsuina Ilon Black GL (CI Acid Black 52), Aizen Opal Black WH Extra Conc (CI Acid Black 52), Sumilan Black WA (CI Acid Black 52), Ranil Black BG Extra Conc (CI Acid Black 107), Kayanol Milling Black TLB (CI Acid Black 109), Sumilan Milling Black B (CI Acid Black 109), Kayanol Milling Black TLR (CI Acid Black 110), Aizen Opal Black New Conc (CI Acid Black 119), Water Black 187-L (CI Acid Black 154), Kayaku Acid Brilliant Flavin FF (CI Acid Yellow 7:1), Kayasil Yellow GG (CI Acid Yellow 17), Xylene Light Yellow 2G 140% (CI Acid Yellow 17), Suminol Leveling Yellow NR (CI Acid Yellow 19), Daiwa Tatrazine (CI Acid Yellow 23), Kayaku Tatrazine (CI Acid Yellow 23), Suminol Fast Yellow -R (CI Acid Yellow 25), Diacid Light Yellow 2GP (CI Acid Yellow 29), Suminol Milling Yellow (CI Acid Yellow 38), Water Yellow 6 (CI Acid Yellow 42), Water Yellow 6C (CI Acid Yellow 42), Kayanol Yellow NFG (CI Acid Yellow 49), Suminol Milling Yellow 3G (CI Acid Yellow 72), Suminol Fast Yellow G (CI Acid Yellow 61), Suminol Milling Yellow G (CIAcid Yellow 78), Kayanol Yellow N5G (CI Acid Yellow 110), Suminol Milling Yellow 4G 200% (CI Acid Yellow 141), Kayanol Yellow NG (CI Acid Yellow 135), Kayanol Milling Yellow 5GW (CI Acid Yellow 127), Kayanol Milling Yellow 6GW (CI Acid Yellow 142), Sumitomo Fast Scarlet A (CI Acid Red 8), Kayaku Silk Scarlet (CI Acid Red 9), Solar Rubin Ex Stra (CI Acid Red 14), Daiwa New Kokushin (CI Acid Red 18), Water Red 1 (CI Acid Red 18), Aizen Bonso RH (CI Acid Red 26), Daiwa Red No. 2 (CI Acid Red 27), Suminol Leveling Brilliant Red S3B (CI Acid Red 35), Kayasil Rubinol 3GS (CI Acid Red 37), Aizen Erythrosine (CI Acid Red 51), Daiwa Red No. 106WB (CI Acid Red 52), Suminol Leveling Rubinol 3GP (CI Acid Red 57), Diacid Alizarin Rubinol F3G 200% (CI Acid Red 82), Aizen Eosin GH (CI Acid Red 87), Daiwa Red No. 104WB (CI Acid Red 92), Aizen Acid Phloxine PB (CI Acid Red 92), Rose Bengal (CI Acid Red 94), Kayanol Milling Scarlet FGW (CI Acid Red 111), Kayanol Milling Rubin 3BW (CI Acid Red 129) , Suminol Milling Brilliant Red 3BN Concentrate (CI Acid Red 131), Suminol Milling Brilliant Red BS (CI Acid Red 138), Aizen Opal Pink BH (CI Acid Red 186), Suminol Milling Brilliant Red B Concentrate (CI Acid Red 249), Kayaku Acid Brilliant Red 3BL (CI Acid Red 254), Kayaku Acid Brilliant Red BL (CI Acid Red 265), Kayanol Milling Red GW (CIAcid Red 276), Mitsui Acid Violet 6BN (CI Acid Violet 15), Mitsui Acid Violet BN (CI Acid Violet 17), Sumitomo Patent Pure Blue VX (CI Acid Blue 1), Water Blue #106 (CI Acid Blue 1), Patent Blue AF (CI Acid Blue 7), Water Blue 9 (CI Acid Blue 9), Daiwa Blue No.1 (CI Acid Blue 9), Supranol Blue B (CI Acid Blue 15), Orient Soluble Blue OBC (CI Acid Blue 22), Suminol Leveling Blue 4GL (CI Acid Blue 23), Mitsui Nylon Fast Blue G (CI Acid Blue 25), Kayasil Blue AGG (CI Acid Blue 40), Kayasil Blue BR (CI Acid Blue 41), Mitsui Alizarin Sapphirol SE (CI Acid Blue 43), Suminol Leveling Sky Blue R Extra Conc (CI Acid Blue 62), Mitsui Nylon Fast Sky Blue B (CI Acid Blue 78), Sumitomo Brilliant Toy Indocyanin 6Bh / c (CI Acid Blue 83), Sandran Cyanin N-6B 350% (CI Acid Blue 90), Water Blue #115 (CI Acid Blue 90), Orient Soluble Blue OBB (CI Acid Blue 93), Sumitomo Brilliant Blue 5G (CI Acid Blue 103), Kayanol Milling Ultra Sky SE (CI Acid Blue 112), Kayanol Milling Cyanin 5R (CI Acid Blue 113), Aizen Opal Blue 2GLH (CI Acid Blue 158), Acid dyes such as Daiwa Guinea Green B (CI Acid Green 3), Acid Brilliant Milling Green B (CI Acid Green 9), Daiwa Green #70 (CI Acid Green 16), Kayanol Cyanine Green G (CI Acid Green 25), Suminol Milling Green G (CI Acid Green 27), Eisen Katilon Yellow 3GLH (CI Basic Yellow 11), Eisen Katilon Brilliant Yellow 5GLH (CI Basic Yellow 13), Sumiacrylic Yellow E-3RD (C.I. Basic Yellow 15), Maxillon Yellow 2RL (CI Basic Yellow 19), Astrazon Yellow 7GLL (CI Basic Yellow 21), Kayakryl Golden Yellow GL-ED (CI Basic Yellow 28), Astrazon Yellow 5GL (CI Basic Yellow 51), Eisen Katiron Orange GLH (CI Basic Orange 21), Eisen Katiron Brown 3GLH (CI Basic Orange 30), Rhodamine 6GCP (CI Basic Red 1), Eisen Astraphloxine (CI Basic Orange 12), Sumiacryl Brilliant Red E-2B (CI Basic Orange 15), Astrazon Red GTL (CI Basic Orange 18), Eisen Katiron Brilliant Pink BGH (CI Basic Orange 19), Examples of basic dyes include CI Basic Orange 27), Maxilon Red GRL (CI Basic Orange 46), Aizen Methyl Violet (CI Basic Violet 1), Aizen Crystal Violet (CI Basic Violet 3), Aizen Rhodamine B (CI Basic Violet 10), Astrazon Blue G (CI Basic Blue 1), Astrazon Blue BG (CI Basic Blue 3), Methylene Blue (CI Basic Blue 9), Maxilon Blue GRL (CI Basic Blue 41), Aizen Catilon Blue BRLH (CI Basic Blue 54), Aizen Diamond Green GH (CI Basic Green 1), Aizen Malachite Green (CI Basic Green 4), and Bismarck Brown G (CI Basic Brown 1). The amount of these dyes is preferably 0.1% by weight or more and 30.0% by weight or less based on the total amount of the aqueous ink composition. If the amount is less than 0.1% by weight, the color tone cannot be adjusted sufficiently, and if the amount is more than 30.0% by weight, the solid content increases, causing the ink viscosity to increase excessively, which tends to deteriorate the writing feel. These dyes may be used alone or in combination of two or more kinds.

[0019] Examples of pigments include organic pigments such as azo pigments, nitroso pigments, nitro pigments, basic dye pigments, acid dye pigments, vapour dye pigments, mordant dye pigments, and natural dye pigments that are used in conventional water-based inks and oil-based inks, and inorganic pigments such as yellow ocher, barium yellow, Prussian blue, cadmium red, barium sulfate, red iron oxide, iron black, and carbon black. In order to increase the dispersion efficiency of these pigments, conventionally known surface active agents, water-soluble resins, and resin emulsions can be preferably used, as well as dispersants that can be used with titanium oxide. These dispersants can also be used in combination. Specifically, Aniline Black (CI50440), Cyanine Black, Naphthol Yellow S (CI10316), Hansa Yellow 10G (CI11710), Hansa Yellow 5G (CI11660), Hansa Yellow 3G (CI11670), Hansa Yellow G (CI11680), Hansa Yellow GR (CI11730), Hansa Yellow A (CI11735), Hansa Yellow RN (CI11740), Hansa Yellow R (CI12710), Pigment Yellow L (CI12720), Benzidine Yellow Yellow (CI21090), Benzidine Yellow G (CI21095), Benzidine Yellow GR (CI21100), Permanent Yellow NCG (CI20040), Balkan Fast Yellow 5G (CI21220), Balkan Fast Yellow R (CI21135), Tartrazine Lake (CI19140), Quinoline Yellow Lake (CI47005), Anthragen Yellow 6GL (CI60520), Permanent Yellow FGL, Permanent Yellow H10G, Permanent Yellow HR, Anthrapyrimidine Yellow (CI 68420), Sudhan I (CI 12055), Permanent Orange (CI 12075), Lithol Fast Orange (CI 12125), Permanent Orange GTR (CI 12305), Hansa Yellow 3R (CI 11725), Balkan Fast Orange GG (CI 21165), Benzidine Orange G (CI 21110), Persian Orange (CI 15510), Indanthrene Brilliant Orange GK (CI 59305), Indanthrene Brilliant Orange Brilliant Orange GR (CI 71105), Permanent Brown FG (CI 12480), Para Brown (CI 12071), Permanent Red 4R (CI 12120), Para Red (CI 12070), Fire Red (CI 12085), Parachlor Orthoaniline Red (CI 12090), Lithol Fast Scarlet, Brilliant Fast Scarlet (CI 12315), Brilliant Carmine BS, Permanent Red F2R (CI12310), Permanent Red F4R (CI12335), Permanent Red FRL (CI12440), Permanent Red FRLL (CI12460), Permanent Red F4RH (CI12420), Fast Scarlet VD, Balkan Fast Rubin B (CI12320), Balkan Fast Pink G (CI12330), Light Fast Red Toner B (CI12450), Light Fast Red Toner R (CI12455), Permanent Carmine FB (CI12490), Pyra Zorone Red (CI12120), Lithol Red (CI15630), Lake Red C (CI15585), Lake Red D (CI15500), Anthocine B (CI18030), Brilliant Scarlet G (CI15800), Lithol Rubin GK (CI15825), Permanent Red F5R (CI15865), Brilliant Carmine 6B (CI15850), Pigment Scarlet 3B (CI16105), Bordeaux 5B (CI12170), Toluidine Maroon (CI12350), Par Manent Bordeaux F2R (CI12385), Helio Bordeaux BL (CI14830), Bordeaux 10B (CI15880), Bon Maroon Light (CI15825), Bon Maroon Medium (CI15880), Eosin Lake (CI45380), Rhodamine Lake B (CI45170), Rhodamine Lake Y (CI45160), Alizarin Lake (CI58000), Thioindigo Red B (CI73300), Thioindigo Maroon (CI73385), Permanent Red FGR (CI12370) ), PV Carmine HR, Watching Red, Monolight Fast Red YS (CI59300), Permanent Red BL, Fast Violet B, Methyl Violet Lake (CI42535), Dioxazine Violet, Alkaline Blue Lake (CI42750A, CI42770A), Peacock Blue Lake (CI42090), Peacock Blue Lake (CI42025), Victoria Blue Lake (CI44045), Phthalocyanine Blue (CI74160), Fast Sky Blue (CI74180), Indanthrene Blue RS (CI 69800), Indanthrene Blue BC (CI 69825), Indigo (CI 73000), Pigment Green B (CI 10006), Naphthol Green B (CI 10020), Green Gold (CI 12775), Acid Green Lake, Malachite Green Lake (CI 42000), Phthalocyanine Green, etc.

[0020] Also, an aqueous pigment base in which a pigment is dispersed in an aqueous medium can be used. Specifically, examples of pigment bases dispersed with a nonionic surfactant include FUJI SP BLACK 8031, FUJI SP BALCK 8041, FUJI SP RED 5628, FUJI SP RED 5648, FUJI SP RED 5653, FUJI SP RED 5657, FUJI SP BLUE 6474, FUJI SP BLUE 6555, FUJI SP YELLOW 4341, FUJI SP YELLOW 4360, FUJI SP YELLOW 4459, FUJI SP VIOLET 9602, FUJI SP VIOLET 9623, FUJI SP PINK 9429, FUJI SP ORANGE 632, and FUJI SP ORANGE 636 (all manufactured by Fuji Pigment Co., Ltd.). Examples of pigment bases dispersed with an anionic surfactant include FUJI SP BLUE 6663, FUJI SP VIOLET 9586, FUJI SP VIOLET 9624 (all manufactured by Fuji Pigment Co., Ltd.), NKW-2101, NKW-2102, NKW-2103, NKW-2104, NKW-2105, NKW-2106, NKW-2107, NKW-2108, NKW-2117, NKW-2127, NKW-2137, NKW-2167, NKW-2101E, NKW-210 2E, NKW-2103E, NKW-2104E, NKW-2105E, NKW-2106E, NKW-2107E, NKW-2109E, NKW-2117E , NKW-2127E, NKW-2137E, NKW-2167E, NKW-2108E, NKW-2101P, NKW-2102P, NKW-2103P, NK W-2104P, NKW-2105P, NKW-2106P, NKW-2107P, NKW-2108P, NKW-2117P, NKW-2127P, NKW- 2137P, NKW-2167P, NKW-C2102E, NKW-C2103E, NKW-C2104E, NKW-C2105E, NKW-C2117E, N KW-C2147E, NKW-C2167E, NKW-C2108E, NKW-3002, NKW-3003, NKW-3004, NKW-3005, NKW- 3007, NKW-3077, NKW-3008, NKW-3202E, NKW-3203E, NKW-3204E, NKW-3205E, NKW-3207E,NKW-3277E, NKW-3208E, NKW-3402, NKW-3404, NKW-3405, NKW-3407, NKW-3408, NKW-3477, NKW-3602, NKW-3603, NKW-3604, NKW-3605, NKW-3607, NKW-3677, NKW-3608, NKW-3702, NKW-3703, NKW-3704, NKW -3705, NKW-3777, NKW-3708, NKW-3902E, NKW-3903E, NKW-3904E, NKW-3905E, NKW-3907E, NKW-3977E, NKW-3908E, NKW-6013, NKW-6038, NKW-6002E, NKW-6013E, NKW-6004E, NKW-6005E, NKW-6007E, NKW-60 47E, NKW-6077E, NKW-6008E, NKW-6038E, NKW-6202E, NKW-6203E, NKW-6253E, NKW-6204E, NKW-6205E, NKW-6207E, NKW-6277E, NKW-6258E, NKW-6200E, NKW-6559, NKW-7002E, NKW-7012E, NKW-7052E, NKW-7 003E, NKW-7004E, NKW-7005E, NKW-7026E, NKW-7017E, NKW-7047E, NKW-7067E, NKW-7008E, NKW-7038E, NKW-7502E, NKW-7517E, NKW-7577E, NKW-7518E (all manufactured by Nippon Fluorescent Chemical Co., Ltd.). SP BLACK 8065, FUJI SP BACK 8175, FUJI SP BLACK 8119, FUJI SP BLACK 8167, FUJI SP BACK 8208, FUJI SP BACK 8231, FUJI SP BLACK 8381, FUJI SP BLACK 8406, FUJI SP BACK 8500, FUJI SP BACK 8871, FUJI SP RED 5220, FUJI SP RED 5530, FUJI SP RED 5709, FUJI SP RED 5721, FUJI SP BLUE 6402, FUJI SP BLUE 6666, FUJI SP GREEN 7275, FUJI SP GREEN 7433,Examples of the pigments include FUJI SP GREEN 7426, FUJI SP YELLOW 4178, FUJI SP YELLOW 4198, FUJI SP YELLOW 4439, FUJI SP YELLOW 4449, FUJI SP YELLOW 4470, FUJI SP VIOLET 9583, FUJI SP VIOLET 9626, FUJI SP PINK 9524, FUJI SP PINK 9527, FUJI SP ORANGE 534, FUJI SP ORANGE 606, and FUJI SP ORANGE 674 (all manufactured by Fuji Pigment Co., Ltd.). In addition, FUJI SP BLACK 8276, FUJI SP BALCK 8551, FUJI SP BACK 8922, FUJI SP RED 5096, FUJI SP RED 5111, FUJI SP RED 5192, FUJI SP RED 5193, FUJI SP RED 5543, FUJI SP RED 5544, FUJI SP RED 5590, FUJI SP BORDEAUX 5500, FUJI SP BLUE 6062, FUJI SP BLUE 6133, FUJI SP BLUE 6134, FUJI SP BLUE 6401, FUJI SP GREEN 7051, FUJI SP YELLOW 4056, FUJI SP YELLOW 4060, FUJI SP YELLOW 4218, FUJI SP VIOLET 9011 (all of the above are manufactured by Fuji Pigment Co., Ltd.); Emacol Black CN, Emacol Blue FBB, Emacol Blue FB, Emacol Blue KR, Emacol Green LXB, Emacol Violet BL, Emacol Brown 3101, Emacol Carmine FB, Emacol Red BS, Emacol Orange R, Emacol Yellow FD, Emacol Yellow IRN, Emacol Yellow 3601, Emacol Yellow FGN, Emacol Yellow GN, Emacol Yellow GG, Emacol Yellow F5G, Emacol Yellow F7G, Emacol Yellow 10GN, Emacol Yellow 10G, Sandye Super Black K, Sandye Super Black C, Sandye Super Grey B, Sandye Super Brown SB, Sandye Super Brown FRL, Sandye Super Brown RR, SandyeSuper Green L5G, SandyeSuper Green GXB, Sandye Super Navy Blue HRL, Sandye Super Navy Blue GLL, Sandye Super Navy Blue HB, Sandye Super NavyBlue FBLH、Sandye Super Navy Blue FBL-160、Sandye Super Navy Blue FBB、Sandye Super Violet BL H / C、Sandye Super Violet BL BL、Sandye Super Bordeaux FR、Sandye Super Pink FBL、Super Pink F5B、Sandye Super Rubine FR、Sandye super Carmmine FB、SandyeSuper Red FFG、SandyeSuper Red RR、SandyeSuper Red BS、Sandye Super Orange FL、Sandye Super Orange R、Sandye Super Orange BO、Sandye Gold Yellow 5GR、Sandye Gold Yellow R、Sandye Gold Yellow 3R、Sandye Ywllow GG、Sandye Ywllow F3R、Sandye Ywllow IRC、Sandye Ywllow FGN, Sandye Ywllow GN, Sandye Ywllow GRS, Sandye Ywllow GSR-130, Sandye Ywllow GSN-130, Sandye Ywllow GSN, Sandye Ywllow 10GN (all manufactured by Sanyo Pigment Co., Ltd.), Rio Fast BlackFx 8012, Rio Fast BlackFx 8313, Rio Fast BlackFx 8169, Rio Fast Red Fx8209, Rio Fast Red Fx 8172, Rio Fast Red S Fx 8315, Rio Fast Red S Fx 8316, Rio Fast Blue Fx 8170, Rio Fast Blue FX 8170, Rio Fast Blue S Fx 8312, Rio Fast Green S Fx 8314 (all manufactured by Toyo Ink Co., Ltd.), Cosmo Color S1000F series (manufactured by Toyo Soda Co., Ltd.), Victoria Yellow G-11, G-20, Victoria Orange G-16, G-21, Victoria Red G-19, G-22, Victoria Pink G-17, G-23, Victoria Green G-18, G-24, Victoria Blue G-15, G-25 (all manufactured by Mikuni Pigment Co., Ltd.), and the Pollux series such as Pollux PC5T1020, Pollux Black PC8T135, and Pollux Red IT1030 (all manufactured by Sumika Color Co., Ltd.). When the ink is toned to a color other than white, the pigment is preferably 0.1% by weight or more and 25.0% by weight or less based on the total amount of the aqueous ink composition. If the amount is less than 0.1% by weight, the color tone may not be adjusted sufficiently. These colorants may be used alone or in combination of two or more kinds.

[0021] The ethylene-vinyl acetate resin emulsion of the present invention, which has an elongation of 400% or more and 1000% or less at 23°C, can fix pigments to the paper surface and improve the drying resistance and pen tip recovery of the pen tip and coating tip. Specific examples of ethylene-vinyl acetate resin emulsions include Sumikaflex 201HQ (elongation at 23°C: 1000%), Sumikaflex 305HQ (elongation at 23°C: 420%), Sumikaflex 355HQ (elongation at 23°C: 420%), Sumikaflex 400HQ (elongation at 23°C: 550%), Sumikaflex 401HQ (elongation at 23°C: 850%), Sumikaflex 408HQE (elongation at 23°C: 650%), Sumikaflex 410HQ (elongation at 23°C: 700%), Sumikaflex 450HQ (elongation at 23°C: 540%), Sumikaflex 455HQ (elongation at 23°C: 50 0%), Sumikaflex 456HQ (elongation 550% at 23°C), Sumikaflex 460HQ (elongation 620% at 23°C), Sumikaflex 465HQ (elongation 750% at 23°C), Sumikaflex 467HQ (elongation 790% at 23°C), Sumikaflex 7400HQ (elongation 810% at 23°C), Sumikaflex 470HQ (elongation 530% at 23°C), Sumikaflex 478HQ (elongation 620% at 23°C), Sumikaflex 483HQ (elongation 400% at 23°C), Sumikaflex 510HQ (elongation 800% at 23°C) (all manufactured by Sumitomo Chemical Co., Ltd.). The elongation of the ethylene-vinyl acetate resin emulsion was measured under the following conditions: the film was approximately 0.15 mm thick (23°C / 65%, dried for 7 days to form a film), the film shape was dumbbell No. 3, and the tensile speed was 500 mm / min. Among ethylene-vinyl acetate resin emulsions, those with an elongation of 650% to 1000% at 23° C. are particularly preferred because they cause little increase in viscosity when water evaporates. High ethylene pigment types are also particularly preferred because of their water resistance, light resistance, and compatibility with non-polar materials. The ethylene-vinyl acetate resin emulsion preferably has a Tg of -50°C or more and 0°C or less, a minimum film-forming temperature (MFT) of 0°C or more, and a viscosity at 25°C of 2500 to 5500. The ethylene-vinyl acetate resin emulsion is preferably from 2.0% by weight to 10.0% by weight in terms of solid content relative to the total amount of the water-based ink composition, since it has good fixability and redispersibility, can maintain low ink viscosity even when dried, and provides good ink discharge, resulting in a good writing feel. These resin emulsions may be used alone or in combination of two or more kinds.

[0022] The polycarbonate-based urethane resin emulsion of the present invention is highly compatible with ethylene-vinyl acetate resin emulsions having an elongation of 400% or more and 1000% or less at 23°C, and therefore when used in combination, the dryness resistance and tip recovery of the nib and application tip are further improved; particularly in brush pens equipped with a tip composed of bundled nylon fibers as tip fibers, the resin inside the tip does not separate even when the nib dries, preventing the nib from cracking and the occurrence of smeared writing at the start of writing. Specific examples of polycarbonate-based urethane resin emulsions include Eukoat UX-320, UX-390, Parmarin UA-300, UA-310, UA-368 (all manufactured by Sanyo Chemical Industries, Ltd.), Superflex 420NS, 460S, 470 (all manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.), Evaphanol HA-50C, HA170 (all manufactured by Nicca Chemical Co., Ltd.), and the like, with anionic emulsions being particularly preferred for the dispersion stability of titanium oxide. The polycarbonate-based urethane resin emulsion preferably has a solid content of 0.03% by weight to 2.0% by weight based on the total weight of the aqueous ink composition. These resin emulsions may be used alone or in combination of two or more kinds.

[0023] Water is used as the main solvent for the ink, and it is preferable to use ion-exchanged water or purified water. Furthermore, any organic solvent that has been conventionally known for the purpose of achieving various qualities as an ink, such as preventing the ink from freezing at low temperatures and preventing the ink from drying at the pen tip, can be used in combination without any particular limitations. Specific examples of organic solvents include glycols such as ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, polyethylene glycol, 1,2-butylene glycol, 1,3-butylene glycol, 2-methylpentane-2,4-diol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, 1,2-hexanediol, 3-methyl-1,3-butanediol, 1,2-propanediol, 1,3-propanediol, thiodiethylene glycol, glycerin, benzyl glycol, and benzyl diglycol; ethylene glycol monomethyl ether, propylene glycol monomethyl ether, diethylene glycol monomethyl ether, dipropylene glycol monomethyl ether, ethylene glycol monoethyl ether, propylene glycol monoethyl ether, diethylene glycol monoethyl ether, ethylene glycol monoisopropyl ether, sulfolane, di Examples of the glycol ethers include propylene glycol monoethyl ether, ethylene glycol monobutyl ether, ethylene glycol monohexyl ether, ethylene glycol monophenyl ether, diethylene glycol monobutyl ether, diethylene glycol monohexyl ether, diethylene glycol monophenyl ether, propylene glycol monobutyl ether, propylene glycol monophenyl ether, tripropylene glycol monobutyl ether, and tripropylene glycol monophenyl ether; alcohol solvents such as isopropyl alcohol, 3-methyl-3-methoxy-1-butanol, benzyl alcohol, α-methylbenzyl alcohol, lauryl alcohol, tridecyl alcohol, isododecyl alcohol, and isotridecyl alcohol; propylene glycol methyl ether acetate, propylene glycol diacetate, 2-pyrrolidone, N-methyl-2-pyrrolidone, sulfolane, and γ-butyrolactone.These organic solvents may be used alone or in combination of two or more. The amount of the organic solvent used may be 1.0% by weight or more and 50.0% by weight or less based on the total amount of the ink composition. In addition, by using a solvent such as 2-methylpentane-2,4-diol that increases the penetration speed into paper, the ink composition can be made to dry quickly.

[0024] A conventionally known wetting agent can be used in combination to prevent the ink from drying out at the writing portion. Urea, ethylene urea, thiourea, sorbitol, sorbitan, etc. can be used as necessary. These wetting agents can be used alone or in combination. The amount of the wetting agent used can be 5.0% by weight or more and 20.0% by weight or less based on the total amount of the ink composition. Among these wetting agents, it is preferable to combine glycerin, ethylene glycol, urea, and ethylene urea from the viewpoints of the drying property of the pen tip, the restorability of the brush tip, and the suppression of precipitation, and further, by combining urea, ethylene urea, and glycerin, it is possible to obtain an aqueous ink composition in which writing is less likely to bleed while ensuring the wettability of the brush tip.

[0025] The pH of the ink composition can be adjusted by using a pH adjuster such as a basic substance such as sodium hydroxide, lithium hydroxide, triethanolamine, diethanolamine, monoethanolamine, aminomethylpropanediol, or a conventionally known acidic substance, and the pH is preferably 4.0 to 10.0, and more preferably 6.0 to 8.0, using these pH adjusters. By adjusting the pH, the pigment dispersion stability over time is further improved. These pH adjusters may be used alone or in combination of two or more kinds.

[0026] In order to improve the fixing property, abrasion resistance, water resistance, etc. of the colorant, a water-soluble resin, a resin emulsion, or a resin dispersion can be used in combination with an ethylene-vinyl acetate resin emulsion or a polycarbonate-based urethane resin emulsion. Examples of such resins include shellac, styrene-maleic acid copolymers and their salts, styrene-acrylic acid copolymers and their salts, α-methylstyrene-acrylic acid copolymers and their salts, acrylic resins, maleic acid resins, urea resins, polyvinyl butyral, polyvinyl acetal, polyamide resins, epoxy resins, polyvinyl alkyl ethers, coumarone-indene resins, rosin-based resins, polyether-based urethane resins, polyester-based urethane resins and their hydrogenated products, ketone resins, and polyacrylic acid-polymethacrylic acid copolymers. These resins can be used alone or in combination. When added to impart fixation to the writing surface, the amount used is preferably 0.1 to 10.0% by weight based on the total amount of the ink composition. They may be used alone or in combination of two or more types, and the pigment dispersion resin can also be used as a fixing agent.

[0027] Examples of acrylic resin emulsions include FK-64S, FK-471, FK-474, FK-285, FK-6100, Mowinyl 952B (all manufactured by Japan Coating Resins Co., Ltd.), Vinisol 1637, 1117, 1008, 1606A, and 911 (all manufactured by Daido Chemical Industry Co., Ltd.), Joncryl HPD-196, HPD-96J, 7100, 711, PDX-7341, PDX-7787, PDX-7734, PDX-7687, 352D, PDX-7164, and PDX-7430 (all manufactured by BASF Japan Ltd.). In particular, Vinizol 1606A (mentioned above) is suitable because it has a high glass transition point and is an acrylic resin with excellent fastness that is emulsified and dispersed to form a coating film, improving the water resistance of handwriting.

[0028] Examples of polyether-based urethane resins and polyester-based urethane resin emulsions include polyester-based urethane resin emulsions such as Acrylic WEM-202U and Acrylic WEM-321U (both manufactured by Taisei Fine Chemical Co., Ltd.), Neo Sticker 400 and Neo Sticker 700 (both manufactured by Nicca Chemical Co., Ltd.), and U-Coat UWS-145 (both manufactured by Sanyo Chemical Industries, Ltd.), and polyether-based urethane resin emulsions such as Parmarin UA-200 (both manufactured by Sanyo Chemical Industries, Ltd.) and Acrylic WBR-016U (both manufactured by Taisei Fine Chemical Co., Ltd.).

[0029] Examples of olefin resin dispersions include ZAIXXEN A, ZAIXXEN L, and ZAIXXEN H (all manufactured by Sumitomo Seika Chemicals Co., Ltd.). In particular, ZAIXXEN H (mentioned above) is preferably used since it has a small number of hydrophilic groups in the monomer and improves the water resistance of handwriting. These water-soluble resins, resin emulsions and resin dispersions can also be used as dispersants for pigments, or can be used in combination.

[0030] Resin particles or aqueous dispersions thereof can be used as the anti-bleeding agent.Specifically, polyethylene waxes such as Hitech E-7025P, Hitech E-2213, Hitech E-6500, Hitech E-6314, Hitech E-6400, Hitech E-9460, Hitech E-9015, Hitech E-4A, Hitech E-5403P, Hitech E-8237, polypropylene waxes such as Hitech P-9018, Hitech P-5300, Hitech P-5800, Hitech P-5060P, carboxyl group-containing ethylene copolymers such as Hitech S-3121, Hitech S-3800, Hitech S-9242, Hitech S-9200, Hitech S-8512, Hitech S-3148K (all manufactured by Toho Chemical Industry Co., Ltd.), etc. can be used. The amount used is preferably 1.0 to 20.0% by weight based on the total amount of the ink composition, but when used alone, if an amount that provides a sufficient anti-bleeding effect is used, the viscosity of the aqueous ink composition itself becomes high, and there is a risk that it may become difficult to discharge due to the relationship with the writing part of the writing instrument used and the flow path of the ink composition, so it is desirable to adjust the amount used appropriately. When the viscosity of the ink composition becomes high when used alone, it can be used at a viscosity suitable for discharge by combining it with another substance that exhibits an anti-bleeding effect.

[0031] In order to obtain suitable flow properties as an aqueous ink composition, a water-soluble polymer compound can be used. For example, gum arabic, tragacanth gum, guar gum, locust bean gum, alginic acid, carrageenan, gelatin, casein, xanthan gum, dextran, welan gum, rhamsan gum, alka gum, methyl cellulose, ethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, carboxymethyl cellulose, sodium starch glycolate, sodium alginate, propylene glycol alginate, hydroxypropyl guar gum, methyl cellulose, ethyl cellulose, polyvinyl alcohol, polyvinylpyrrolidone, polyvinyl methyl ether, polyacrylic acid, carboxyvinyl polymer, polyethylene oxide, copolymer of vinyl acetate and polyvinylpyrrolidone, acrylic resin salt, copolymer of acrylic acid and alkyl methacrylate, or salts thereof can be used, and can also be used as a pigment dispersing resin.

[0032] In order to prevent the growth of mold, antiseptics and fungicides such as sodium dehydroacetate, 1,2-benzisothiazolin-3-one, sodium benzoate, morpholine, morpholine derivatives, and omadine-based agents may be added as appropriate, and these may be used alone or in combination of two or more types.

[0033] Furthermore, various additives such as dye dissolving assistants, rust inhibitors such as benzotriazole, antifoaming agents such as silicone emulsions, and defoaming agents such as ascorbic acid and hydroquinone sulfonates can be used as necessary.

[0034] The aqueous ink composition used in the writing instrument or applicator of the present invention, such as a marking pen or brush pen, is preferably adjusted to have a viscosity of 2 mPa s or more and 50 mPa s or less at a temperature of 25°C and a shear rate of 1000.0 / s, because this ensures the following writing performance and storage stability: writing feel, uniformity of handwriting, handwriting density, suppression of bleeding, ink discharge stability, control of handwriting bleed-through onto the paper, suppression of handwriting smearing, suppression of drying of the pen tip and brush tip, writing performance when dry, and redispersibility of the luster pigment and the like.

[0035] In producing the aqueous ink composition of the present invention, various conventionally known methods can be employed. For example, water and bentonite are put into a stirrer having high shear force, such as a Henschel mixer, a propeller stirrer, a homogenizer, a turbo mixer, a high-pressure homogenizer, or a fine flow mill, and then the luster pigment dispersed by a dispersing machine, such as a Henschel mixer, a propeller stirrer, a homogenizer, a turbo mixer, a high-pressure homogenizer, a ball mill, a bead mill, or a roll mill, and other remaining components are put into the composition, and the composition is further mixed and stirred to obtain the aqueous ink composition. In addition, in these preparation steps, the mixture can be stirred by utilizing the generated dispersion heat as it is, or by applying heat or by cooling and stirring. Removal of bubbles by a defoamer or filtration of coarse particles by a filter may be performed as necessary. Each of these various mixing steps, dispersing steps, filtering steps, heating steps, or cooling steps may be performed alone, or two or more steps may be performed in parallel.

[0036] The ink composition of the present invention can be used as a coating liquid for various applicators. Examples of the form of the applicator include writing instruments such as brush pens, ballpoint pens, felt-tip pens, and marking pens, drawing instruments, and cosmetic tools such as eyeliners, eyebrow pencils, and eyeshadows.

[0037] Hereinafter, one embodiment of an applicator containing an ink composition according to the present invention will be described with reference to the drawings. Note that the technical scope of the present invention is not limited to the embodiment, and various modifications are possible without departing from the gist of the present invention.

[0038] 1 is a vertical cross-sectional view of an applicator 1. The applicator 1 is a so-called brush pen. The applicator 1 has a barrel 2 as a base, and various components are housed and arranged around the barrel 2.

[0039] The axle cylinder 2 is a cylindrical member formed by joining a front axle 2a and a rear axle 2b. Both the front axle 2a and the rear axle 2b are molded products made of polypropylene resin. Both the front axle 2a and the rear axle 2b are cylindrical members that are hollow members that are open on both axial ends and penetrate in the axial direction.

[0040] A flange, which is a circumferential protrusion, is provided at the middle of the outer wall of the front axle 2a in the axial direction. A front axle 2a-side fitting portion, which is a circumferential protrusion, is provided at the rear of the flange on the outer wall of the front axle 2a. A rear axle 2b-side fitting portion, which is a circumferential protrusion, is provided on the inner wall in front of the rear axle 2b. The rear of the front axle 2a is inserted through the front end opening of the rear axle 2b, and the front axle 2a-side fitting portion and the rear axle 2b-side fitting portion climb over each other to complete the fitting, and the front axle 2a and the rear axle 2b are joined. At this time, the front end face of the rear axle 2b abuts against the flange of the front axle 2a, allowing the axial positioning of both components to be determined.

[0041] The front axle 2a and the rear axle 2b can be appropriately connected by a method such as a jump-over fit as in this embodiment, a connection by press fitting, a screw connection, etc. Furthermore, the axle cylinder 2 does not have to be a connection of two parts, the front axle 2a and the rear axle 2b as in this embodiment, but can be formed from one hollow cylindrical molded part or by connecting three or more parts.

[0042] The inside of the rear barrel 2b is a coating liquid tank 2ba in which the coating liquid (ink composition according to the present invention) is directly stored. In this embodiment, 3.0 g of coating liquid is stored. The rear of the rear barrel 2b is open via a double-cylinder structure of an inner cylinder 2bb and an outer cylinder 2bc, and a packing member 3 and a knock member 4 are arranged therein.

[0043] The inner cylinder 2bb is located radially inward from the outer cylinder 2bc and forms an opening at the rear of the coating liquid tank 2ba. The opening is covered with a packing member 3. The packing member 3 is made of butyl rubber and is therefore elastic, and can be attached to the inner cylinder 2bb in a liquid-tight manner, thereby preventing the coating liquid from leaking from the opening of the inner cylinder 2bb. The front of the packing member 3 is arranged in a press-fit state between the outer wall of the inner cylinder 2bb and the inner wall of the outer cylinder 2bc.

[0044] The outer cylinder 2bc forms an opening behind the rear axle 2b. The knock member 4 is arranged in the opening so as to be movable back and forth. The knock member 4 is a cylindrical member molded from polypropylene resin. The outer cylinder 2bc has two window holes that penetrate from the inside to the outside and extend in the axial direction, at positions that face each other in the circumferential direction. A protrusion 4a provided on the outer wall of the knock member 4 is inserted into the window hole, thereby preventing the knock member 4 from falling off the outer cylinder 2bc.

[0045] In addition to the coating liquid, a rod member 5 and an agitator 6 are arranged in the coating liquid tank 2ba. The rod member 5 is a member that advances by pressing the knock member 4 to operate a valve mechanism described later. The rod member 5 is a cylindrical member that is open at both axial ends and is a hollow member that penetrates in the axial direction. The rear of the rod member 5 protrudes from an opening at the rear of the coating liquid tank 2ba. The rod member 5 is a molded product made of polypropylene resin.

[0046] The agitator 6 is a member for moving back and forth within the coating liquid tank 2ba by shaking the applicator 1, thereby agitating the coating liquid. The agitator 6 is a cylindrical member that is open at both axial ends, is a hollow member that penetrates in the axial direction, and has the rod member 5 inserted therethrough. The agitator 6 is a member made by mixing polypropylene resin and talc.

[0047] A valve seat member 7 is disposed in the front shaft 2a. The valve seat member 7 is a member that forms a flow path that supplies the coating liquid in the coating liquid tank 2ba to the coating destination side. The valve seat member 7 is a cylindrical member that is open at both axial ends and is a hollow member that penetrates in the axial direction. A circumferential protrusion is provided at the middle of the axial direction of the outer wall of the valve seat member 7. A front shaft 2a side fitting portion that is a circumferential protrusion is provided on the inner wall of the front shaft 2a. The front of the valve seat member 7 is inserted from the opening at the rear of the front shaft 2a, and the fitting is completed when the valve seat member 7 side fitting portion and the front shaft 2a side fitting portion pass over each other, and the valve seat member 7 is disposed in the front shaft 2a. The valve seat member 7 is a molded product made of polypropylene resin.

[0048] A connection member 8 is disposed within the valve seat member 7. The connection member 8 is a cylindrical member that is open at both axial ends and is a hollow member that penetrates in the axial direction. The connection member 8 is disposed within the valve seat member 7 so as to be movable back and forth. Eight ribs, which are protrusions extending in the axial direction, are formed on the outer wall of the connection member 8 at equal intervals in the circumferential direction. The space formed by the grooves between the ribs and the inner wall of the valve seat member 7 serves as a flow path for the coating liquid. The connection member 8 is a molded product made of polypropylene resin.

[0049] The front of the valve rod member 9 and the rear of the brush tip 10, which is the application destination, are arranged inside the connection member 8. The valve rod member 9 is a rod-shaped member with a large diameter at the front and a small diameter at the rear. The rear of the valve seat member 7 is opened via a double-cylinder structure of the inner tube 7a and the outer tube 7b, and only the rear small diameter part of the valve rod member 9 inserted from the front opening of the valve seat member 7 can be inserted into the opening formed by the inner tube 7a as a flow path for the application liquid. The rear part of the valve rod member 9 protruding from the rear opening of the valve seat member 7 is inserted into the front opening of the rod member 5 and fixed in a pressed-in state. The valve rod member 9 is a molded product made of polypropylene resin.

[0050] A cylindrical coil spring 11 is arranged to be wound around the outer wall of the small diameter portion at the rear of the valve rod member 9. The front end of the coil spring 11 abuts against a step that serves as a seat protruding from the inner wall surface of the inner cylinder 7a, and the rear end of the coil spring 11 abuts against the front end surface that serves as a seat of the rod member 5, and is arranged in a compressed state. The rod member 5 is constantly urged rearward by the elastic force of the coil spring 11.

[0051] The coil spring 11 is preferably made of stainless steel (SUS304) because it is highly durable against repeated use and has excellent corrosion resistance against the coating liquid.

[0052] As described above, the rod member 5 and the valve rod member 9 are fixed, and therefore the valve rod member 9 is also urged backward by the rearward urging force that the rod member 5 receives from the coil spring 11. The large diameter part at the front of the valve rod member 9 is larger in diameter than the opening formed by the inner cylinder 7a as a flow path for the coating liquid and cannot pass through, and the part of the valve rod member 9 that goes from the small diameter part to the large diameter part is circumferentially pressed against the edge part of the opening of the inner cylinder 7a, so that the valve rod member 9 functions as a plug that closes the flow path for the coating liquid formed by the valve seat member 7.

[0053] When the knock member 4 is pressed forward from the state in which the valve rod member 9 is in the rearmost position, the rod member 5 moves forward against the rear biasing force of the coil spring 11. When the valve rod member 9 fixed to the rod member 5 moves forward as the rod member 5 moves forward, the portion of the valve rod member 9 from the small diameter portion to the large diameter portion moves forward away from the edge of the opening of the inner cylinder 7a, opening the flow path for the coating liquid. The coating liquid is supplied from the coating liquid tank 2ba through the flow path between the outer wall of the valve rod member 9 and the inner wall of the inner cylinder 7a, through the flow path between the outer wall of the connection member 8 and the inner wall of the valve seat member 7, to the brush tip 10.

[0054] The front of the brush tip 10, which is connected to the rod member 9 via the connecting member 8, protrudes from the opening in front of the front shaft 2a and functions as an application destination. Because the brush tip 10 is connected to the rod member 9 by the connecting member 8, it moves back and forth within the front shaft 2a and the valve seat member 7 as the rod member 9 moves back and forth. Because the brush tip 10 moves back and forth every time the valve mechanism is operated, even if a coating liquid with a relatively high solid content is used, such as the coating liquid of the present invention, the solid content is less likely to harden around the brush tip 10, which is preferable as it allows the supply of coating liquid to be maintained smoothly.

[0055] The material of the brush tip fiber used in the brush tip 10 can be appropriately selected from nylon (6,6-nylon, 6-nylon, 12-nylon, 6,10-nylon, 6,12-nylon, etc.), polyester (polybutylene terephthalate, polyethylene terephthalate, polybutylene naphthalate, polyethylene naphthalate, polytrimethylene terephthalate, etc.), polyurethane, polyacrylonitrile, acrylonitrile-styrene copolymer, acrylonitrile-butadiene copolymer, etc., or composites of these materials. In addition, inorganic fillers such as calcium, manganese, zinc, copper, calcium carbonate, kaolinite, clay, and aluminum hydroxide can be added to the material resin from which the brush tip fiber is obtained using these materials to impart mechanical and physical properties such as strength, abrasion resistance, chemical resistance, heat resistance, and shape stability, or the particle size and amount of these inorganic powders on the surface can be adjusted to adjust the desired surface roughness. The brush tip 10 according to this embodiment is constructed by converging nylon fibers as brush tip fibers. Nylon fibers have hydrophilic properties due to the amide groups in the molecule, and become relatively soft by absorbing the liquid medium of the coating solution. Nylon fibers are superior in abrasion resistance and flex recovery compared to other synthetic fibers, so they are preferable because they do not break or change shape with repeated use.

[0056] A cap 12 is removably disposed on the front shaft 2a so as to cover the front of the brush tip 10. A protrusion 12a is provided on the outer wall of the cap 12, which prevents the cap 12 or the applicator 1 with the cap 12 attached from rolling on the placement surface. The cap 12 is a molded product made of polypropylene resin.

[0057] The material of each resin molded product can be appropriately selected from polypropylene resin, polycarbonate resin, acrylic resin, polyethylene resin, polyamide resin, polybutylene terephthalate resin, polybutylene naphthalate resin, polyethylene naphthalate resin, vinyl chloride resin, ethylene-vinyl alcohol copolymer, polyacrylonitrile resin, fluororesin, polyacetal resin, polyethylene terephthalate resin, polystyrene resin, ABS resin, silicone resin, elastomer, or composite material containing these resins, taking into consideration moldability, reactivity with the coating liquid, etc. Also, various coatings or printing can be applied to the inner wall surface and / or outer wall surface of each member, taking into consideration reactivity, permeability, etc. depending on the coating liquid used.

[0058] In the exemplary embodiment shown in FIG. 1 , the writing instrument has a tapered tip made of nylon fiber with a diameter of 3.4 mm at the application tip, the tip extending length is in the range of 11.0±1.0 mm, a cap that protects the application tip is removable from the tip of the front barrel, the color of the ink composition contained therein can be distinguished by this cap, the writing instrument has a coating liquid tank in which the ink composition can be directly contained, and the coating liquid tank is partially transparent so that the amount and color of the ink composition can be distinguished, the coating liquid tank has an agitator that redisperses the ink composition, and a valve mechanism is arranged at the connection between the application tip and the coating liquid tank, and the valve mechanism is opened and closed by a rear end knock operation to control the supply of ink to the application tip, making it a brush pen-type applicator with a so-called rear end knock type valve mechanism. EXAMPLES

[0059] The present invention will now be described in detail with reference to examples.

[0060] (Preparation of Ink Composition) Ink compositions of Examples 1 to 8 and Comparative Examples 1 to 12 having the formulations shown in Tables 1 to 3 below were prepared. Specifically, the following materials were used for each composition shown in Tables 1 to 3.

[0061] (1) FUJI SP WHITE 1209 (dispersed pigment of titanium oxide, pigment solid content 45.00 to 55.00% by weight, cationic water-soluble resin dispersant, manufactured by Fuji Pigment Co., Ltd.) (2) TITANIX JR602 (titanium oxide, manufactured by Teika Corporation) (3) TITANIX JR600A (titanium oxide, manufactured by Teika Corporation) (4) JR-405 (titanium oxide, manufactured by Teika Corporation) (5) SandyeSuperColour BLUE GLL-E (organic pigment, manufactured by Sanyo Pigment Co., Ltd.) (6) NKW-2109E (manufactured by Nippon Fluorescent Chemical Co., Ltd.) (7) NKW-C 2102E (manufactured by Japan Fluorescent Chemical Co., Ltd.) (8) NKW-C 2104E (manufactured by Japan Fluorescent Chemical Co., Ltd.) (9) NKW-C 2105E (manufactured by Japan Fluorescent Chemical Co., Ltd.) (10) NKW-C 2108E (manufactured by Japan Fluorescent Chemical Co., Ltd.) (11) NKW-C 2117E (manufactured by Japan Fluorescent Chemical Co., Ltd.) (12) NKW-C 2167E (manufactured by Japan Fluorescent Chemical Co., Ltd.) (13) NKW-6202E (manufactured by Japan Fluorescent Chemical Co., Ltd.) (14) NKW-6205E (manufactured by Japan Fluorescent Chemical Co., Ltd.) (15) NKW-6258E (manufactured by Japan Fluorescent Chemical Co., Ltd.) (16) Satintone 5HB (Kaolin, manufactured by BASF) (17) Sumikaflex 201HQ (elongation at 23°C: 1000%, manufactured by Sumitomo Chemical Co., Ltd.) (18) Sumikaflex 752 (elongation at 23°C: 360%, manufactured by Sumitomo Chemical Co., Ltd.) (19) Sumikaflex 755 (elongation at 23°C: >1500%, manufactured by Sumitomo Chemical Co., Ltd.) (20) U-coat UX-390 (polycarbonate-based urethane resin emulsion, manufactured by Sanyo Chemical Industries, Ltd.) (21) Joncryl J61J (Johnson Polymer Co., Ltd.) (22) Mowinyl 727 (manufactured by Hoechst Chemical Co., Ltd.) (23) JONCRYL JDX-6180 (styrene-acrylic acid copolymer, manufactured by BASF) (24) Anti-Terra 250 (alkylol ammonium salt of high molecular weight acidic polymer, manufactured by BYK-Chemie) (25) F-907A (Carboxymethylcellulose 10% aqueous solution, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) (26) JONCRYL PDX-7430 (styrene-acrylic acid copolymer, manufactured by BASF) (27) JONCRYL PDX-7164 (styrene-acrylic acid copolymer, manufactured by BASF) (28) Ceraflour 929 (modified polyethylene wax, manufactured by BYK) (29) Ceraflour 925 (modified polyethylene wax, manufactured by BYK) (30) Ethylene glycol (manufactured by Japan Alcohol Sales Co., Ltd.) (31) Diethylene glycol (manufactured by Japan Alcohol Sales Co., Ltd.) (32) Glycerin (manufactured by Miyoshi Oil Co., Ltd.) (33) Dynol 604 (acetylene glycol, manufactured by Nissin Chemical Industry Co., Ltd.) (34) BYK-094 (manufactured by BYK Japan Co., Ltd.) (35) BYK-024 (manufactured by BYK Japan Co., Ltd.) (36) Sanai Back Sodium Omajin (manufactured by Sanai Oil Co., Ltd.) (37) PROXEL GXL(S) (Manufactured by Lonza Japan Co., Ltd.) (38) Proxel XL-2 (Lonza Japan Co., Ltd.) (39) BTA (manufactured by Orient Chemical Industries Co., Ltd.) The ink compositions of the respective Examples and Comparative Examples were prepared as follows. (Examples 1 to 8, Comparative Examples 1 to 8) Except for the pigment, ethylene-vinyl acetate resin emulsion, and polycarbonate-based urethane resin emulsion, they were stirred at room temperature using a turbo mixer for 10 minutes, then the pigment was added, and stirring was continued for another 30 minutes. Then, the ethylene-vinyl acetate resin emulsion and polycarbonate-based urethane resin emulsion were added, and stirring was continued for another 30 minutes to obtain an ink composition. (Comparative Examples 9 to 12) Except for NKW-2109E, they were dispersed in a ball mill for 24 hours. Then, NKW-2109E was added to Comparative Examples 9 and 10, and stirring was carried out using a turbo mixer for 60 minutes to obtain an ink composition.

[0062] (Test Samples) To evaluate the ink compositions according to the examples and comparative examples, the ink compositions were filled into the Pentel Pen XGFH-X manufactured by Pentel Co., Ltd., which has a coating liquid tank made of polypropylene, a nib made of nylon fiber with a tapered treatment, and a nib diameter of 3.4 mm. After pressing 10 times, the ink composition was sufficiently penetrated into the nib to obtain a writing sample, and a confirmation test was conducted.

[0063] Using the writing samples filled with the ink compositions of Examples 1 to 8 and Comparative Examples 1 to 12 described above, the pen tip restorability test and the handwriting fixability test described below were conducted.

[0064] (Pen Tip Restorability Test) The knock member of the writing sample was pressed 10 times. With the ink composition sufficiently penetrated into the nib, after writing the character "永" five times on high-quality paper in a size of 2 cm square, the cap was removed and left horizontally in an atmosphere at a temperature of 20 ± 5 degrees and a humidity of 65 ± 5% for 5 hours to dry the nib. After putting on the cap and leaving it horizontally in the same atmosphere for another 24 hours, writing was carried out without pressing. Those with no blurred handwriting are marked as 〇, those with blurred writing at first but no subsequent blurring are marked as △, and those with non-restorable blurring are marked as ×.

[0065] (Handwriting Fixability Test) Press the knock member of the note sample 10 times. With the ink composition sufficiently penetrated into the nib, write the character "永" five times on high-quality paper in a size of 2 cm square. After that, place the high-quality paper after 5 minutes, and move it back and forth 5 times with a weight having a bottom diameter of 50 mm and a weight of 500 g to check for stains on the paper surface. Those with no change in handwriting are marked as 〇, and those with smeared handwriting are marked as ×.

[0066] <ph> The pH (indicated as pH in the table) of the ink composition of each of the Examples and Comparative Examples was measured. The pH was measured at a temperature of 25° C. using a HORIBA "D-71". The pH of the ink composition is preferably 4.0 to 10.0, and more preferably 6.0 to 8.0. If the pH of the aqueous ink composition is within the above numerical range, the pigment dispersion stability of the ink can be improved.

[0067] <Viscosity> The viscosity of each of the Examples and Comparative Examples was measured at a temperature of 25°C and a shear rate of 1000.0 / s (indicated as viscosity@1000.0 in the table). The unit of the measurement results shown in the table is [mPa·s]. The viscosity was measured using Anton Paar's "MCR-302", and the measurement conditions were a temperature of 25°C and a 50 mm cone plate (1°).

[0068] [Table 1]

[0069] [Table 2]

[0070] [Table 3]

[0071] Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and also includes modifications to the above-described embodiments and appropriate combinations of these modifications.

[0072] In this specification, expressions such as "identical," "equal," and "homogeneous" that indicate that things are in an equal state not only indicate a state of strict equality, but also indicate a state in which there is a tolerance or a difference to the extent that the same function is obtained. In addition, in this specification, the expressions "comprise," "include," or "have" a certain element are not exclusive expressions that exclude the presence of other elements. [Explanation of symbols]

[0073] 1 Applicator 2 shaft cylinder 2a front axle 2b rear axle 2ba Coating fluid tank 2bb inner cylinder 2bc Outer cylinder 3 Packing material 4 Knock parts 4a protrusion 5 Bar member 6 Agitator 7 Valve seat material 7a Inner cylinder 7b Outer cylinder 8 Connection parts 9 Valve rod parts 10 Brush Tip 11 Coil spring 12 Cap 12a protrusion< / ph>

Claims

[Claim 1] A water-based ink composition comprising at least titanium oxide as a white pigment, an ethylene-vinyl acetate resin emulsion having an elongation of 400% to 1000% at 23°C, a polycarbonate-based urethane resin emulsion, and water.

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