Water-based pigment ink composition for writing instruments

Abstract

To provide a water-based pigment ink composition for writing instruments that can form good writing marks even after let stand in a subzero temperature environment at about -5°C for 3 months or longer.SOLUTION: A water-based pigment ink composition for writing instruments has a pigment, an amino acid anionic surfactant composed of an unsaturated fatty acid, an amino acid anionic surfactant composed of a saturated fatty acid, and water.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to an aqueous pigment ink composition for writing instruments that uses a pigment as a coloring component in order to obtain effects such as a hiding effect on a base, a gloss effect on a coating mark, and water resistance of a coating mark, which is used by being incorporated in a writing instrument.

Background Art

[0002] Conventionally, an aqueous pigment ink composition for writing instruments that uses a pigment as a coloring component to obtain effects such as a hiding effect on a base, a gloss effect on a coating mark, and water resistance of a coating mark has a higher specific gravity than a dye and is dispersed and mixed rather than dissolved. Therefore, over time, the pigment gradually aggregates and settles, forming a so-called hard cake and separating from the liquid component, which makes it difficult to be discharged from the application site of the writing instrument. In such an ink composition using a pigment, as means for delaying the aggregation and sedimentation of the pigment, methods such as surface modification of the pigment with various surfactants and reducing the fluidity of the liquid by using a thickener or a gelling agent are known. For example, in the invention described in Patent Document 1, a water-soluble resin such as an acrylic resin, a vinyl-based resin, various resin emulsions, a water-soluble polysaccharide such as a cellulose derivative, an inorganic thickener such as a montmorillonite-based clay mineral, etc. are used to obtain an ink having a specific viscosity with respect to a specific shear rate. Thus, an aqueous ink composition for writing instruments having good redispersibility even when left standing at 40°C for 2 weeks is obtained. Further, in Patent Document 2, an aqueous pigment ink composition for a ballpoint pen is disclosed, in which a plurality of specific water-soluble polysaccharides are used in combination, and the dispersion system of the ink can be kept stable and good handwriting can be formed even after storage at a low temperature of about 0°C or a high temperature of about 60°C for about two months as well as at room temperature.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

SUMMARY OF THE INVENTION

PROBLEMS TO BE SOLVED BY THE INVENTION

[0004] In the invention described in the above patent document, there was a problem that it became impossible to write well in an environment of a negative temperature of less than -5°C for a long period of more than three months over time.

[0005] An object of the present invention is to provide an aqueous pigment ink composition for writing instruments that can form a good coating trace even when left standing for three months or more in a negative temperature environment of about -5°C.

MEANS FOR SOLVING THE PROBLEMS

[0006] A first gist of the present invention is an aqueous pigment ink composition for writing instruments comprising at least a pigment, an amino acid anionic surfactant composed of an unsaturated fatty acid, an amino acid anionic surfactant composed of a saturated fatty acid, and water. A second gist is an aqueous pigment ink composition for writing instruments containing a resin emulsion and a plate-like inorganic compound.

EFFECTS OF THE INVENTION

[0007] According to an embodiment of the present invention, it is possible to provide an aqueous pigment ink composition for writing instruments that can be filled into writing instruments such as marking pens, fountain pens, ballpoint pens, correction fluid applicators, etc., and can be written well even when used for writing in the same low temperature environment after being stored for a long time in a negative environment.

[0008] That is, in the aqueous pigment ink composition for writing instruments of the present invention, an amino acid anionic surfactant composed of an unsaturated fatty acid and an amino acid anionic surfactant composed of a saturated fatty acid are bound to the surface of the pigment, and the pigment surface is covered with an amino acid anionic surfactant composed of an unsaturated fatty acid and an amino acid anionic surfactant composed of a saturated fatty acid to form a composite. It is presumed that the interaction between the pigments is made sterically gentle and the fluidity of the entire composition is not impaired even in a low-temperature environment. Further, when a resin emulsion or plate-like inorganic particles are added thereto, a gentle gel structure that wraps the pigment is formed by the thickening effect due to the blending of solids and the gelling action of plate-like inorganic particles such as bentonite. In particular, a large gel structure composite is formed by the interaction between the amino acid anionic surfactant composed of an unsaturated fatty acid, the amino acid anionic surfactant composed of a saturated fatty acid, and the gel structure formed by the plate-like inorganic particles, and a situation where large plate-like pigments such as shiny plate-like aluminum or aluminum flakes as pigment particles are aligned and aggregated is also suppressed.

Brief Description of the Drawings

[0009]

Figure 1

Embodiments for Carrying Out the Invention

[0010] The pigments used in the aqueous pigment ink composition for writing instruments of the present invention are those used as coloring components for obtaining effects such as the hiding effect of the base, the brilliance effect of the coating marks, and the water resistance of the coating marks. The pigments that can be used can be used without particular limitation, and include azo pigments, nitroso pigments, nitro pigments, basic dye pigments, acidic dye pigments, resist dye pigments, mordant dye pigments, natural dye pigments, and other organic pigments used in conventional aqueous inks, oil-based inks, etc., inorganic pigments such as loess, barium yellow, ultramarine blue, cadmium red, barium sulfate, titanium oxide, Indian red, iron black, carbon black, etc., metal powders such as aluminum powder and bronze powder, brilliant pigments such as metal-coated glass flakes and metal-evaporated films, and aqueous pigment bases in which pigments are dispersed in an aqueous medium. In particular, brilliant pigments and the like are mentioned in order to form a beautiful writing stroke with a brilliant feeling.

[0011] As the brilliant pigments, there are LG neo R-GOLD #35, LG neo B-GOLD #35, LG neo S-GOLD #35, LG neo R-GOLD #100, LG neo B-GOLD #100, LG neo S-GOLD #100, LG neo RED #100, LG neo BLUE #100, LG neo GREEN #100, LG neo VIOLET #100, LG neo BLACK #100, LG neo COPPER #100, LG neo PINK #100, LG neo YELLOW #100, LG neo R-GOLD #150, LG neo B-GOLD #150, LG neo S-GOLD #150, LG neo RED #150, LG neo BLUE #150, LG neo GREEN #150, LG neo VIOLET #150, LG neo BLACK #150, LG neo COPPER #150, LG neo PINK #150, LG neo YELLOW #150, LG neo R-GOLD #200, LG neo B-GOLD #200, LG neo S-GOLD #200, LG neo RED #200, LG neo BLUE #200, LG neo GREEN #200, LG neo VIOLET #200, LG neo BLACK #200, LG neo COPPER #200, LG neo PINK #200, LG neo YELLOW #200, LG neo R-GOLD #325, LG neo B-GOLD #325, LG neo S-GOLD #325, LG neo RED #325, LG neo BLUE #325, LG neo GREEN #325, LG neo VIOLET #325, LG neo BLACK #325, LG neo COPPER #325, LG neo PINK #325, LG neo YELLOW #325, LG neo SILVER #325, LG neo R-GOLD #500, LG neo B-GOLD #500, LG neo S-GOLD#500 (manufactured by Oike Imaging Co., Ltd.), Diamond Piece LG Gold No.55, Diamond Piece DG Gold No.55, Diamond Piece Green No.55, Diamond Piece Blue No.55, Diamond Piece Red No.55, Diamond Piece Maroon No.55, Diamond Piece Ocean Green No.55, Diamond Piece Sky Blue No.55, Diamond Piece Black No.55, Diamond Piece Pink No.55, Diamond Piece Violet No.55, Diamond Piece Emerald No.55, Diamond Piece Copper No.55, Diamond Piece LG Gold H25, Diamond Piece DG Gold H25, Diamond Piece Green H25, Diamond Piece Blue H25, Diamond Piece Red H25, Diamond Piece Maroon H25, Diamond Piece Ocean Green H25, Diamond Piece Sky Blue H25, Diamond Piece Black H25, Diamond Piece Pink H25, Diamond Piece Violet H25, Diamond Piece Emerald H25, Diamond Piece Copper H25, Diamond Piece LG Gold H55, Diamond Piece DG Gold H55, Diamond Piece Green H55, Diamond Piece Blue H55, Diamond Piece Red H55, Diamond Piece Maroon H55, Diamond Piece Ocean Green H55, Diamond Piece Sky Blue H55, Diamond Piece Black H55, Diamond Piece Pink H55, Diamond Piece Violet H55, Diamond Piece Emerald H55, Diamond Piece Copper H55, Diamond Piece LG Gold CO-40UC, Diamond Piece DG Gold CO-40UC, Diamond Piece Green CO-40UC, Diamond Piece Blue CO-40UC, Diamond Piece Red CO-40UC, Diamond PiecePink CO-40UC, Diamond Piece Lavender CO-40UC (both manufactured by Daiya Kogyo Co., Ltd.), Super Fine No. 22000, the same No. 22000WN, the same No. 1800WN, the same No. 18000, Fine No. 900, the same No. 800 (all manufactured by Yamato Metal Powder Industry Co., Ltd.), AA12, AA8, No. 900, No. 1800, Pale Gold E5, the same 2L5, Rich Gold L7, the same 3L7, E Copper (all manufactured by Fukuda Metal Foil & Powder Industry Co., Ltd.), Aluminum Powder 1000, the same 2700 (both manufactured by Nakatsuka Metal Foil & Powder Industry Co., Ltd.), WB0230, WXM0630, Friend Color D452BL, Friend Color D462BL, Friend Color D851BL, Friend Color D451RE, Friend Color D462RE, Friend Color D111RE, Friend Color D452YE, Friend Color D462YE, Friend Color D851YE (all manufactured by Toyo Aluminum Co., Ltd.), Stainless Steel Powder Pigment, Tin Powder Pigment, Zinc Powder Pigment, Nickel Powder Pigment, Gold Powder Pigment, Silver Powder Pigment, Meta Shine MT1030GP, Meta Shine MT2080GP, Meta Shine 2025PS, Meta Shine 1030PS, Meta Shine 2080PS, Meta Shine 5090PS, Meta Shine 5150PS, Meta Shine 5230PS, Meta Shine 5480PS (all manufactured by Nippon Sheet Glass Co., Ltd.), etc. When using a brilliant pigment or the like, in order to form a brilliant and beautiful handwriting, it is preferably that the average particle size is 10 μm or more, and when the average particle size is 30 μm or more, the brilliance is further enhanced, which is particularly preferable.

[0012] Examples of inorganic pigments include aniline black (C.I. 50440), cyanine black, naphthol yellow S (C.I. 10316), Hansa yellow 10G (C.I. 11710), Hansa yellow 5G (C.I. 11660), Hansa yellow 3G (C.I. 11670), Hansa yellow G (C.I. 11680), Hansa yellow GR (C.I. 11730), Hansa yellow A (C.I. 11735), Hansa yellow RN (C.I. 1740), Hansa yellow R (C.I. 12710), Pigment yellow L (C. I.12720), Benzidine Yellow (C.I.21090), Benzidine Yellow G (C.I.21095), Benzidine Yellow GR (C.I.21100), Permanent Yellow NCG (C.I.20040), Vulcan Fast Yellow 5G (C.I.21220), Vulcan Fast Yellow R (C.I.21135), Tartrazine Lake (C.I.19140), Quinoline Yellow Lake (C.I.47005), Anthragen Yellow 6GL (C.I.60520), Permanent Yellow FGL, Permanent Yellow H10G, Permanent Yellow HR, Anthrapyrimidine Yellow (C.I.68420), Sudan I (C.I.12055), Permanent Orange (C.I.12075), Resorcin Fast Orange (C.I.12125), Permanent Orange GTR (C.I.12305), Hansa Yellow 3R (C.I.11725), Vulcan Fast Orange GG (C.I.21165), Benzidine Orange G (C.I.21110), Persian Orange (C.I.15510), Indanthrene Brilliant Orange GK (C.I.59305), Indanthrene Brilliant Orange RK (C.I.59105), Indanthrene Brilliant Orange GR (C.I.71105), Permanent Brown FG (C.I.12480), Para Brown (C.I.12071), Permanent Red 4R (C.I.12120), Para Red (C.I.12070), Fire Red (C.I.12085), Parachloroorthoaniline Red (C.I.12090), Resorcin Fast Scarlet, Brilliant Fast Scarlet (C.I.12315), Brilliant Carmine BS, Permanent Red F2R (C.I.12310), Permanent Red F4R (C.I.12335), Permanent Red FRL (C.I.12440), Permanent Red FRLL (C.I.12460), Permanent Red F4RH (C.I.12420), Fast Scarlet VD, Vulcan Fast Rubine B (C.I.12320), Vulcan Fast Pink G (C.I.12330), Light Fast Red Toner B (C.I.12450), Light Fast Red Toner R (C.I.12455), Permanent Carmine FB (C.I.12490), Pyrazolone Red (C.I. 12120), Resorcin Red (C.I. 15630), Lake Red C (C.I. 15585), Lake Red D (C.I. 15500), Anthocyanin B (C.I. 18030), Brilliant Scarlet G (C.I. 15800), Resorcin Rubine GK (C.I. 15825), Permanent Red F5R (C.I. 15865), Brilliant Carmine 6B (C.I. 15850), Pigment Scarlet 3B (C.I. 16105), Bordeaux 5B (C.I. 12170), Toluidine Maroon (C.I. 12350), Permanent Bordeaux F2R (C.I. 12385), Helio Bordeaux BL (C.I. 14830), Bordeaux 10B (C.I. 15880), Bon Maroon Light (C.I. 15825), Bon Maroon Medium (C.I. 15880), Eosin Lake (C.I. 45380), Rhodamine Lake B (C.I. 45170), Rhodamine Lake Y (C.I. 45160), Alizarin Lake (C.I. 58000), Thioindigo Red B (C.I. 73300), Thioindigo Maroon (C.I. 73385), Permanent Red FGR (C.I. 12370), PV Carmine HR, Watching Red, Monolite Fast Red YS (C.I. 59300), Permanent Red BL, Fast Violet B, Methyl Violet Lake (C.I. 42535), Dioxazine Violet, Alkali Blue Lake (C.I. 42750A, C.I. 42770A), Peacock Blue Lake (C.I. 42090), Peacock Blue Lake (C.I. 42025), Victoria Blue Lake (C.I. 44045), Phthalocyanine Blue (C.I. 74160), Fast Sky Blue (C.I. 74180), Indanthrene Blue RS (C.I. 69800), Indanthrene Blue BC (C.I. 69825), Indigo (C.I. 73000), Pigment Green B (C.I. 10006), Naphthol Green B (C.I. 10020), Green Gold (C.I. 12775), Acid Green Lake, Malachite Green Lake (C.I. 42000), Phthalocyanine Green, etc.

[0013] As the water-based pigments, there are Fuji SP Black 8031, Fuji SP Black 8119, Fuji SP Black 8167, Fuji SP Black 8276, Fuji SP Black 8381, Fuji SP Black 8406, Fuji SP Red 5096, Fuji SP Red 5111, Fuji SP Red 5193, Fuji SP Red 5220, 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 4060, Fuji SP Yellow 4178, Fuji SP Violet 9011, Fuji SP Pink 9524, Fuji SP Pink 9527, Fuji SP Orange 534, Fuji SP Brown 3074, Fuji SP RED 5543, FUJI SP RED 5544 (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, Sandye Super Green L5G, Sandye Super GreenGXB, Sandye Super Navy Blue HRL, Sandye Super Navy Blue GLL, Sandye Super Navy Blue HB, Sandye Super Navy Blue FBLH, Sandye Super Navy Blue FBL-160, Sandye Super Navy Blue FBB, Sandye Super Violet BL H / C, Sandye Super Violet BL, Sandye Super Bordeaux FR, Sandye Super Pink FBL, Sandye Super Pink F5B, Sandye Super Rubine FR, Sandye super Carmine FB, Sandye Super Red FFG, Sandye Super Red RR, Sandye Super 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 Yellow GG, Sandye Yellow F3R, Sandye Yellow IRC, Sandye Yellow FGN, Sandye Yellow GN, Sandye Yellow GRS, Sandye Yellow GSR-130, Sandye Yellow GSN-130, Sandye Yellow GSN, Sandye Yellow 10GN (above, manufactured by Sanyo Shikiso Co., Ltd.), Rio Fast Black Fx 8012, Rio Fast Black Fx 8313, Rio Fast Black Fx 8169, Rio Fast Red Fx 8209, 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 Fx8314 (manufactured by Toyo Ink Co., Ltd. above), 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-2101P, NKW-2102P, NKW-2103P, NKW-2104P, NKW-2105P, NKW-2106P, NKW-2107P, NKW-2108P, NKW-2117P, NKW-2127P, NKW-2137P, NKW-2167P, NKW-3002, NKW-3003, NKW-3004, NKW-3005, NKW-3007, NKW-3077, NKW-3008, 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-6013, NKW-6038, NKW-6559 (manufactured by Nippon Fluorescent Co., Ltd. above), Cosmo Color S1000F series (manufactured by Toyo Soda Manufacturing Co., Ltd.), Victoria Yellow G-11, the same G-20, Victoria Orange G-16, the same G-21, Victoria Red G-19, the same G-22, Victoria Pink G-17, the same G-23, Victoria Green G-18, the same G-24, Victoria Blue G-15, the same G-25 (manufactured by Mikuni Shikiso Co., Ltd. above), Pollux PC5T1020, Pollux Black PC8T135, Pollux series such as Pollux Red IT1030 (manufactured by Sumika Color Co., Ltd. above), etc. are mentioned.

[0014] These pigments may be used alone or in combination of two or more. It is preferable that the pigment is 0.5% by weight or more and 20.0% by weight or less based on the total amount of the aqueous pigment ink composition. Further, 1.0% by weight or more and 10.0% by weight or less is more preferable. Within the above numerical range, stable ink ejection performance can be obtained without clogging of the pigment at the pen tip or nozzle tip while maintaining fluidity at low temperatures.

[0015] As the colorant, dyes can be used in combination with the above pigments. As the dyes, direct dyes, acid dyes, basic dyes and the like used in conventional aqueous inks, oil-based inks and the like can be used. Specifically, Japanol Fast Black D Conc. (C.I. Direct Black 17), Water Black 100L (C.I. Direct Black 19), Water Black L-200 (C.I. Direct Black 19), Water Black 256L, Direct Fast Black B (C.I. Direct Black 22), Direct Fast Black AB (C.I. Direct Black 32), Direct Deep Black EX (C.I. Direct Black 38), Direct Fast Black Conc. (C.I. Direct Black 51), Kayarus Spra Gray VGN (C.I. Direct Black 71), Kayarus Direct Brilliant Yellow G (C.I. Direct Yellow 4), Direct Fast Yellow 5GL (C.I. Direct Yellow 26), Eisen Primula Yellow GCLH (C.I. Direct Yellow 44), Direct Fast Yellow R (C.I. Direct Yellow 50), Eisen Direct Fast Red FH (C.I. Direct Red 1), Nippon Fast Scarlet GSX (C.I. Direct Red 4), Direct Fast Scarlet 4BS (C.I. Direct Red 23), Eisen Direct Red Durin BH (C.I. Direct Red 31), Direct Scarlet B (C.I. Direct Red 37), Kayaku Direct Scarlet 3B (C.I. Direct Red 39), Eisen Primula Pink 2BLH (C.I. Direct Red 75), Sumilight Red F3B (C.I. Direct Red 80), Eisen Primula Red 4BH (C.I. Direct Red 81), Kayarus Spural Bin BL (C.I. Direct Red 83), Kayarus Light Red F5G (C.I. Direct Red 225), Kayarus Light Red F5B (C.I. Direct Red 226), Kayarus Light Rose FR (C.I. Direct Red 227), Direct Sky Blue 6B (C.I. Direct Blue 1), Direct Sky Blue 5B (C.I. Direct Blue 15), Sumilight Spra Blue BRR Conc. (C.I. Direct Blue 71), Diogen Turquoise Blue S (C.I. Direct Blue 86), Water Blue 3 (C.I. Direct Blue 86), Kayarus Turquoise Blue GL (C.I.Direct dyes such as Direct Blue 86), Kayarus Supra Blue FF2GL (C.I. Direct Blue 106), Kayarus Supra Turquoise Blue FBL (C.I. Direct Blue 199), and acid dyes such as Acid Blue Black 10B (C.I. Acid Black 1), Nigrosine (C.I. Acid Black 2), Suminoir Milling Black 8BX (C.I. Acid Black 24), Kayanol Milling Black VLG (C.I. Acid Black 26), Suminoir Fast Black BR Conc. (C.I. Acid Black 31), Mitsui Nylon Black GL (C.I. Acid Black 52), Eisen Opal Black WH Extra Conc. (C.I. Acid Black 52), Sumiran Black WA (C.I. Acid Black 52), Ranil Black BG Extra Conc. (C.I. Acid Black 107), Kayanol Milling Black TLB (C.I. Acid Black 109), Suminoir Milling Black B (C.I. Acid Black 109), Kayanol Milling Black TLR (C.I. Acid Black 110), Eisen Opal Black New Conc. (C.I. Acid Black 119), Water Black 187-L (C.I. Acid Black 154), Kayak Acid Brilliant Flavin FF (C.I. Acid Yellow 7:1), Kayasil Yellow GG (C.I. Acid Yellow 17), Xylene Light Yellow 2G 140% (C.I. Acid Yellow 17), Suminoir Levelling Yellow NR (C.I. Acid Yellow 19), Daiwa Tartrazine (C.I. Acid Yellow 23), Kayak Tartrazine (C.I. Acid Yellow 23), Suminoir Fast Yellow R (C.I. Acid Yellow 25), Dia Acid Light Yellow 2GP (C.I. Acid Yellow 29), Suminoir Milling Yellow (C.I. Acid Yellow 38), Water Yellow 6 (C.I. Acid Yellow 42), Water Yellow 6C (C.I. Acid Yellow 42), Kayanol Yellow NFG (C.I. Acid Yellow 49), Suminoir Milling Yellow 3G (C.I. Acid Yellow 72), Suminoir Fast Yellow G (C.I. Acid Yellow 61), Suminoir Milling Yellow G (C.I.Acid Yellow 78), Kayanol Yellow N5G (C.I. Acid Yellow 110), Suminole Milling Yellow 4G200% (C.I. Acid Yellow 141), Kayanol Yellow NG (C.I. Acid Yellow 135), Kayanol Milling Yellow 5GW (C.I. Acid Yellow 127), Kayanol Milling Yellow 6GW (C.I. Acid Yellow 142), Sumitomo Fast Scarlet A (C.I. Acid Red 8), Kayaku Silk Scarlet (C.I. Acid Red 9), Solar Rubine Extra (C.I. Acid Red 14), Daiwa New Coccine (C.I. Acid Red 18), Water Red 1 (C.I. Acid Red 18), Eisenbon Sour RH (C.I. Acid Red 26), Daiwa Red No. 2 (C.I. Acid Red 27), Suminole Levelling Brilliant Red S3B (C.I. Acid Red 35), Kayashiru Rubinol 3GS (C.I. Acid Red 37), Eisen Erythrosin (C.I. Acid Red 51), Daiwa Red No. 106WB (C.I. Acid Red 52), Suminole Levelling Rubinol 3GP (C.I. Acid Red 57), Dia Acid Alizarin Rubinol F3G200% (C.I. Acid Red 82), Eisen Eosin GH (C.I. Acid Red 87), Daiwa Red No. 104WB (C.I. Acid Red 92), Eisen Acid Fluoroxine PB (C.I. Acid Red 92), Rose Bengal (C.I. Acid Red 94), Kayanol Milling Scarlet FGW (C.I. Acid Red 111), Kayanol Milling Rubine 3BW (C.I. Acid Red 129), Suminoall Milling Brilliant Red 3BN Conc (C.I. Acid Red 131), Suminole Milling Brilliant Red BS (C.I. Acid Red 138), Eisen Opal Pink BH (C.I. Acid Red 186), Suminole Milling Brilliant Red B Conc (C.I. Acid Red 249), Kayaku Acid Brilliant Red 3BL (C.I. Acid Red 254), Kayaku Acid Brilliant Brilliant Red BL (C.I. Acid Red 265), Kayanol Milling Red GW (C.I.Acid Red 276), Mitsui Acid Violet 6BN (C.I. Acid Violet 15), Mitsui Acid Violet BN (C.I. Acid Violet 17), Sumitomo Patent Pure Blue VX (C.I. Acid Blue 1), Water Blue 106 (C.I. Acid Blue 1), Water Blue 119, Patent Blue AF (C.I. Acid Blue 7), Water Blue 9 (C.I. Acid Blue 9), Daiwa Blue No.1 (C.I. Acid Blue 9), Supranol Blue B (C.I. Acid Blue 15), Orient Soluble Blue OBC (C.I. Acid Blue 22), Suminolevelling Blue 4GL (C.I. Acid Blue 23), Mitsui Nylon Fast Blue G (C.I. Acid Blue 25), Kayasil Blue AGG (C.I. Acid Blue 40), Kayasil Blue BR (C.I. Acid Blue 41), Mitsui Alizarin Sapphilor SE (C.I. Acid Blue 43), Suminolevelling Sky Blue R Extra Conc (C.I. Acid Blue 62), Mitsui Nylon Fast Sky Blue B (C.I. Acid Blue 78), Sumitomo Brilliant Indocyanine 6Bh / c (C.I. Acid Blue 83), Sandolan Cyanine N-6B 350% (C.I. Acid Blue 90), Water Blue 115 (C.I. Acid Blue 90), Orient Soluble Blue OBB (C.I. Acid Blue 93), Sumitomo Brilliant Blue 5G (C.I. Acid Blue 103), Kayanol Milling Ultra Sky SE (C.I. Acid Blue 112), Kayanol Milling Cyanine 5R (C.I. Acid Blue 113), Eisen Opal Blue 2GLH (C.I. Acid Blue 158), Daiwa Ginia Green B (C.I. Acid Green 3), Acid Brilliant Milling Green B (C.I. Acid Green 9), Daiwa Green 70 (C.I. Acid Green 16), Kayanol Cyanine Green G (C.I. Acid Green 25), Suminolevelling Green G (C.I. Acid Green 27) and other acid dyes, Eisen Catilon Yellow 3GLH (C.I. Basic Yellow 11), Eisen Catilon Brilliant Yellow 5GLH (C.I.Basic Yellow 13), Sumiacryl Yellow E-3RD (C.I. Basic Yellow 15), Maxilon Yellow 2RL (C.I. Basic Yellow 19), Astrazon Yellow 7GLL (C.I. Basic Yellow 21), Kayacryl Golden Yellow GL-ED (C.I. Basic Yellow 28), Astrazon Yellow 5GL (C.I. Basic Yellow 51), Eisen Catilon Orange GLH (C.I. Basic Orange 21), Eisen Catilon Brown 3GLH (C.I. Basic Orange 30), Rhodamine 6GCP (C.I. Basic Red 1), Eisen Astrafluoquine (C.I. Basic Orange 12), Sumiacryl Brilliant Red E-2B (C.I. Basic Orange 15), Astrazon Red GTL (C.I. Basic Orange 18), Eisen Catilon Brilliant Pink BGH (C.I. Basic Orange 27), Maxilon Red GRL (C.I. Basic Orange 46), Eisen Methyl Violet (C.I. Basic Violet 1), Eisen Crystal Violet (C.I. Basic Violet 3), Eisen Rhodamine B (C.I. Basic Violet 10), Astrazon Blue G (C.I. Basic Blue 1), Astrazon Blue BG (C.I. Basic Blue 3), Methylene Blue (C.I. Basic Blue 9), Maxilon Blue GRL (C.I. Basic Blue 41), Eisen Catilon Blue BRLH (C.I. Basic Blue 54), Eisen Diamond Green GH (C.I. Basic Green 1), Eisen Malachite Green (C.I. Basic Green 4), Bismarck Brown G (C.I. Basic Brown 1), and other basic dyes are mentioned. These dyes may be used alone or in a mixture of two or more. Preferably, the dye is 0.001% by weight or more and 30.0% by weight or less based on the total amount. If it is less than 0.001% by weight, the color tone adjustment is not sufficient, and if it is more than 30.0% by weight, the viscosity of the ink extremely increases and the writing feel tends to deteriorate.

[0016] The amino acid anionic surfactant composed of unsaturated fatty acids used in the present invention and the amino acid anionic surfactant composed of saturated fatty acids are used in combination. The amino acid anionic surfactant is preferably used in an amount of 0.1% by weight or more and 5.0% by weight or less based on the total amount of the aqueous pigment ink composition. Within the above numerical range, stable ink ejection performance can be obtained while maintaining the dispersion stability at low temperatures.

[0017] Examples of the amino acid anionic surfactant composed of unsaturated fatty acids include NIKKOL Sarcosinate OH (oleoyl sarcosine (condensate of oleic acid and methyl glycine)), NIKKOL Sarcosinate OHV (oleoyl sarcosine (condensate of oleic acid and methyl glycine)) (both manufactured by Nikko Chemicals Co., Ltd.), etc. The unsaturated fatty acid is a fatty acid having a carbon-carbon double bond. It is preferable that the cis-type carbon-carbon double bond is more than the trans-type carbon-carbon double bond in the carbon-carbon double bond because fluidity is more exhibited.

[0018] Examples of amino acid anion surfactants composed of saturated fatty acids include Amisoft CS-11 (sodium N-coconut oil fatty acid acyl-L-glutamate), Amisoft CA (N-coconut oil fatty acid acyl-L-glutamate), Amisoft LA-D (N-lauroyl-L-glutamate), Amisoft HA-P (N-stearoyl-L-glutamate), Amisoft LS-11 (sodium N-lauroyl-L-glutamate), Amisoft MK-11 (potassium N-myristoyl-L-glutamate), Amisoft MS-11 (sodium N-myristoyl-L-glutamate), Amisoft GS-11P (sodium N-acyl-L-glutamate), Amisoft HS-11P (sodium N-stearoyl-L-glutamate), Amisoft CT-12 (aqueous solution of triethanolamine salt of N-coconut oil fatty acid acyl-L-glutamate), Amisoft LT-12 (aqueous solution of triethanolamine salt of lauroyl-L-glutamate), Amisoft CK-22 (aqueous solution of potassium salt of N-coconut oil fatty acid acyl-L-glutamate), Amisoft CS-22 (aqueous solution of sodium salt of N-coconut oil fatty acid acyl-L-glutamate) (all of the above are manufactured by Ajinomoto Health Supply Co., Ltd.), NIKKOL Alaninate LN-30 (30% aqueous solution of sodium lauroylmethylalanine), NIKKOL Sarcosinate CN-30 (30% aqueous solution of sodium cocoyl sarcosinate (sodium salt of condensate of coconut oil fatty acid and methylglycine)), NIKKOL Sarcosinate CT-30 (30% aqueous solution of triethanolamine salt of cocoyl sarcosine (condensate of coconut oil fatty acid and methylglycine)), NIKKOL Sarcosinate LH (lauroyl sarcosine), NIKKOL Sarcosinate LN (sodium lauroyl sarcosine), NIKKOL Sarcosinate LN-30 (sodium lauroyl sarcosine, 30% aqueous solution), NIKKOL Sarcosinate LK-30 (potassium lauroyl sarcosine, 30% aqueous solution), NIKKOL Sarcosinate MN (sodium myristoyl sarcosine), NIKKOL Sarcosinate PN (sodium palmitoyl sarcosine) (all of the above are manufactured by Nikko Chemicals Co., Ltd.), etc.An amino acid anionic surfactant in which the amino acid moiety is glutamic acid is preferable because it has two carboxylic acids and thus the binding to the pigment is stable. Incidentally, an amino acid anionic surfactant composed of coconut oil fatty acids contains not only an amino acid anionic surfactant composed of saturated fatty acids but also an amino acid anionic surfactant composed of unsaturated fatty acids in an amount of about several weight % as impurities. However, when these are used alone with the content of the amino acid anionic surfactant composed of unsaturated fatty acids being less than about 10% by weight, the substantial combined effect is not exhibited. It is substantially necessary that the content of each of the amino acid anionic surfactant composed of unsaturated fatty acids and the amino acid anionic surfactant composed of saturated fatty acids is 10% by weight or more based on the content of the total amino acid anionic surfactant in the ink composition. When the content of the amino acid anionic surfactant composed of unsaturated fatty acids is 20% by weight or more based on the content of the total amino acid anionic surfactant in the ink composition and the content of the amino acid anionic surfactant composed of saturated fatty acids is 20% by weight or more based on the content of the total amino acid anionic surfactant in the ink composition, the interaction between pigments is made sterically mild so that the fluidity of the whole composition is not impaired even in a low-temperature environment, and the effect of enabling good writing is enhanced, which is preferable. Furthermore, when the content of the amino acid anionic surfactant composed of unsaturated fatty acids is 30% by weight or more based on the content of the total amino acid anionic surfactant in the ink composition and the content of the amino acid anionic surfactant composed of saturated fatty acids is 30% by weight or more based on the content of the total amino acid anionic surfactant in the ink composition, the interaction between pigments is made sterically mild so that the fluidity of the whole composition is not impaired even in a low-temperature environment, and the effect of enabling good writing is further enhanced, which is particularly preferable.

[0019] As the plate-like inorganic compound of the present invention, smectite group, bentonite, etc. that can be dispersed in water to form a gel structure can be used. Bentonite is an inorganic mineral mainly composed of montmorillonite and accompanied by accessory components such as quartz, cristobalite, feldspar minerals, and carbonate minerals. Due to the gelling action of plate-like inorganic particles such as bentonite, a gentle gel structure that wraps the pigment is formed. In particular, a large gel structure complex is formed by the interaction between the amino acid activator composed of unsaturated fatty acid, the amino acid activator composed of saturated fatty acid, and the gel structure formed by the plate-like inorganic particles, suppressing the situation where large plate-like pigments such as shiny plate-like aluminum or aluminum flakes as pigment particles align and aggregate, and it is used to enable the stable ejection of the pigment onto the writing surface. Specific examples of the plate-like inorganic compound include OPTIGEL-WX, OPTIGEL-CG, OPTIGEL-CK, OPTIGEL-CK XR, OPTIGEL-CL, OPTIGEL-CMO, OPTIGEL-LX, OPTIGEL-W 724, OPTIGEL-WA, OPTIGEL-WH, OPTIGEL-WM, OPTIGEL-WX XR, LAPONITE-RD, LAPONITE-EP, LAPONITE-RDS, LAPONITE-JS, LAPONITE-S482 (the above are manufactured by BYK-Chemie Japan Co., Ltd.), BENGEL, BENGEL HV, BENGEL FW, BENGEL 15, BENGEL 23, BENGEL SH, BENGEL A, BENGEL W-100, BENGEL W-100U, BENGEL W-200U, BENGEL W-300U, BENGEL W-300HP, ESVEN NX, ESVEN NX80, ESVEN NZ, ESVEN NZ, 70 ESVEN NEZ, ESVEN NO12S, ESVEN NO12 (the above are manufactured by Hoojun Co., Ltd.), Kunipia-F, Kunipia-G, Kunipia-G4, Moistnite-U, Moistnite-S, Smeton-SA, Smeton-ST, Smeton-SWN, Smeton-SWF, Smeton-SEN (the above are manufactured by Kunimine Co., Ltd.), etc. These plate-like inorganic compounds may be used alone or in admixture of two or more. The plate-shaped inorganic compound is preferably 0.05% by weight or more and 3.0% by weight or less based on the total amount of the aqueous pigment ink composition. More preferably, it is 0.1% by weight or more and 2.0% by weight or less. Within the above numerical range, stable ink ejection performance can be obtained without clogging of the pigment at the pen tip or nozzle tip while maintaining the dispersion stability at low temperatures. If it is more than 3.0% by weight, the viscosity of the ink extremely increases and the writing quality is likely to deteriorate.

[0020] The resin emulsion of the present invention imparts flexibility to a composite of an amino acid activator composed of an unsaturated fatty acid and an amino acid activator composed of a saturated fatty acid that covers the pigment surface by binding the hydrophobic portion to an amino acid anionic surfactant, and imparts fluidity even in a super-low temperature state with few diffusion phenomena. Examples of the resin emulsion include urethane resin emulsion, acrylic resin emulsion, acrylic-urethane resin emulsion, vinyl acetate resin emulsion, and the like. Specifically, Eucote UWS-145 (solid content 35%), Eucote UX-300 (solid content 38%), Eucote UX-310 (solid content 40%), Permaline UA-150 (solid content 30%), Permaline UA-200 (solid content 30%), Permaline UA-368 (solid content 50%), Permaline UA-4000 (solid content 38%) (all manufactured by Sanyo Chemical Industries, Ltd.), Acrit WBR-016U (solid content 30%) (manufactured by Dainippon Fine Chemical Co., Ltd.), Neo Sticker 200 (solid content 35%), Neo Sticker 400 (solid content 37%), Neo Sticker 700 (solid content 37%), Neo Sticker 1200 (solid content 37%), Evafanol HA-15 (solid content 30%), Evafanol HA-107C (solid content 40%), Evafanol HA-50C (solid content 35%), Evafanol HA-170 (solid content 37%), Evafanol HA-560 (solid content 35%) (all manufactured by Nippon Kayaku Co., Ltd.), Bonron XGS-001 (solid content 45%), Bonron XPL-100 (solid content 30%), Bonron XPL-200 (solid content 44%), Bonron PS-001 (solid content 50%), Bonron PS-002 (solid content 45%), Bonron XPS-004 (solid content 45%), Bonron XHS-20 (solid content 40%), Bonron XHS-21S (solid content 45%), Bonron XHS-50 (solid content 20%), Bonron S-119H (solid content 50%), Bonron S-416BF (solid content 44.5%), Bonron S-415 (solid content 44%), Bonron S-403 (solid content 25%), Bonron S-476 (solid content 45%), Bonron S-1120 (solid content 45%), Bonron S-483TBF (solid content 45%), Bonron S-434 (solid content 45%), Bonron S-1360 (solid content 44.5%) (all manufactured by Mitsui Chemicals, Inc.), DM772 (solid content 46%), DM774 (solid content 46%) (all manufactured by Japan Coating Resin Co., Ltd.), Acrit AKW-107 (solid content 30%), Acrit ATW-008S (solid content 29.5%) (all manufactured by Dainippon Fine Chemical Co., Ltd.), Joncryl 7100 (solid content 48.0%), Joncryl 711 (solid content 42.0%), Joncryl PDX-7370 (solid content 42.0%), Joncryl PDX-7323 (solid content 42.0%), Joncryl PDX-7611 (solid content 36.5%), Joncryl 352D (solid content 45.0%), Joncryl 538J (solid content 45.0%), Joncryl PDX-7700 (solid content 48.0%), Joncryl PDX-7177 (solid content 36.0%), Joncryl 7001 (solid content 87.0%) (above, manufactured by BASF (Germany)), Aquabrid 46777 (solid content 30%), Aquabrid UX-100 (solid content 48%), Aquabrid UX-110 (solid content 48%), Aquabrid AST531 (solid content 56%), Aquabrid AST499 (solid content 40%), Sevian-A886 (solid content 42%) (above, manufactured by Daicel Finechem Co., Ltd.), Boncoat 40-418EF (solid content 55%), Boncoat 5400EF (solid content 55%), Boncoat 5495EF (solid content 55%), Boncoat CG-8400 (solid content 50%), Boncoat CG-8490 (solid content 50%), Boncoat CG-8520 (solid content 49%), Boncoat CG-8680 (solid content 50%), Boncoat CM-8430 (solid content 40%), Boncoat CP-6450 (solid content 40%), Boncoat DV-961 (solid content 40%), Boncoat EC-740EF (solid content 40%), Boncoat EC-905EF (solid content 50%), Boncoat SFC-55 (solid content 40%) (above, manufactured by DIC Corporation), Acrit WEM-202U (solid content 40%) composed of acrylic-urethane resin emulsion, Acrit WEM-321U (solid content 38%), Acrit WEM-3008 (solid content 32.5% or more (manufactured by Taisei Fine Chemical Co., Ltd.), Polyzol S-5J (solid content 52%) consisting of vinyl acetate resin emulsion, Polyzol AX-590 (solid content 49%), Polyzol AX-751 (solid content 46%), Polyzol AX-428J (solid content 46%), Polyzol AX-510ZL (solid content 43%), Polyzol AX-951 (solid content 41%), Polyzol AX-1000 (solid content 39%), Polyzol BX-8004 (solid content 48%), Polyzol AX-747L (solid content 50%), Polyzol P-503 (solid content 40%), Polyzol PS-120 (solid content 50%), Polyzol S-65 (solid content 50%) (manufactured by Showa Denko K.K. as above), Sebian-A210 (solid content 52%), Sebian-A215 (solid content 52.5%), Sebian-A217 (solid content 52.5%), Sebian-A218 (solid content 59%), Sebian-A220 (solid content 48%), Sebian-A240 (solid content 53.5%), Sebian-A415 (solid content 55%), Sebian-A435 (solid content 57%) (manufactured by Daicel Finechem Ltd. as above), etc. can be mentioned. These resin emulsions may be used alone or in admixture of two or more kinds. The resin emulsion is preferably 1.0% by weight or more and 10.0% by weight or less as the solid content based on the total amount of the aqueous pigment ink composition. Within the above numerical range, stable ink ejection properties can be obtained while maintaining fluidity at low temperatures.

[0021] Water is used as the main solvent of the ink. In the present invention, the main solvent means a solvent that occupies 50% by weight or more of the total amount of solvents in the total amount of the ink composition. It is preferable to use ion-exchanged water or purified water. Furthermore, as long as it is an organic solvent that has been conventionally known for various purposes as ink, such as preventing ink freezing at low temperatures and preventing ink drying at the pen tip, it is not particularly limited and can be used in combination. Specific examples of the organic solvent include glycols such as ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, polyethylene glycol, 1,2-butylene glycol, 1,3-butylene glycol, thiodiethylene glycol, glycerin, benzyl glycol, and benzyldiglycol; glycol ethers such as 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, dipropylene 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; and propylene glycol methyl ether acetate, propylene glycol diacetate, 2-pyrrolidone, N-methyl-2-pyrrolidone, sulfolane, γ-butyrolactone, etc. These organic solvents may be used alone or in a mixture of two or more.

[0022] The pH of the ink composition can be adjusted by using basic substances such as sodium hydroxide, lithium hydroxide, triethanolamine, diethanolamine, monoethanolamine, aminomethylpropanediol, and pH adjusters such as conventionally known acidic substances. By adjusting the pH to 6.0 or higher and 10.0 or lower with these pH adjusters, the effect of maintaining the fluidity of the ink composition is further improved. Furthermore, by adjusting the pH to 7.0 or higher and 9.0 or lower, it becomes easier to form a bond between the amino acid anionic surfactant composed of unsaturated fatty acid and the pigment surface of the amino acid anionic surfactant composed of saturated fatty acid, and it is expected to maintain the fluidity of the aqueous pigment ink composition for writing instruments in the long term. These pH adjusters may be used alone or in combination of two or more.

[0023] In addition, various additives can be used as appropriate according to need. For example, in order to improve the fixing property of the pigment, a wax emulsion can be used. Specifically, RK-185 (solid content 45%) made of paraffin wax (manufactured by Gohou Chemical Industry Co., Ltd.), WE-65 (solid content 35%) (manufactured by Konishi Co., Ltd.), Chemparl W100 (solid content 40%) made of polyethylene wax, Chemparl W200 (solid content 40%), Chemparl W300 (solid content 40%), Chemparl W310 (solid content 40%), Chemparl W400 (solid content 40%), Chemparl W4005 (solid content 40%), Chemparl W401 (solid content 40%), Chemparl W410 (solid content 40%), Chemparl W500 (solid content 40%), Chemparl WF640 (solid content 40%), Chemparl W700 (solid content 40%), Chemparl W800 (solid content 40%), Chemparl W900 (solid content 40%), Chemparl W950 (solid content 40%) (all of the above are manufactured by Mitsui Chemicals, Inc.), HYTEC E-6500 (solid content 35%), HYTEC E-9015 (solid content 40%), HYTEC E-6400 (solid content 35%), HYTEC E-8237 (solid content 40%), HYTEC E-5403P (solid content 30%), HYTEC E-1000 (solid content 35%), HYTEC E-4A (solid content 35%) (all of the above are manufactured by Toho Chemical Industry Co., Ltd.), HYTEC P-9018 (solid content 35%) made of polypropylene wax, HYTEC P-5300 (solid content 30%), HYTEC P-5800 (solid content 30%), HYTEC P-5060P (solid content 40%) (all of the above are manufactured by Toho Chemical Industry Co., Ltd.), Chemparl A100 (solid content 40%) made of ethylene·α-olefin copolymer (manufactured by Mitsui Chemicals, Inc.), Chemparl V100 (solid content 40%) made of ethylene vinyl acetate copolymer resin, Chemparl V200 (solid content 40%), Chemparl V300 (solid content 40%) (all of the above are manufactured by Mitsui Chemicals, Inc.), HYTEC S-3121 (solid content 25%) made of polyethylene-based copolymer resin, HYTEC S-3800 (solid content 25%), HYTEC S-9242 (solid content 20%), HYTEC S-9200 (solid content 20%), HYTEC S-8512 (solid content 25%), HYTEC S-3148K (solid content 25%) (all of the above are manufactured by Toho Chemical Industry Co., Ltd.), etc. can be mentioned. These wax emulsions may be used alone or in combination of two or more kinds. In addition, as an antiseptic and antifungal agent for the aqueous pigment ink composition, sodium dehydroacetate, 1,2-benzisothiazolin-3-one, sodium 2-pyridinethiol-1-oxide, etc. can also be used. These antiseptic and antifungal agents have a synergistic effect by combining 1,2-benzisothiazolin-3-one and sodium 2-pyridinethiol-1-oxide, and an antiseptic and antifungal effect can be obtained with a smaller content.

[0024] The viscosity of the aqueous pigment ink composition for writing instruments of the present invention is appropriately adjusted according to the embodiments of direct liquid markers, ballpoint pens, brushes, pen pens, correction fluids, etc., and is not particularly limited. By appropriately adjusting according to the embodiments, writing performance and storage stability such as writing feel, uniformity of handwriting, handwriting density, bleeding suppression, ink ejection stability, control of bleeding through the paper of handwriting, suppression of feathering of handwriting, suppression of drying of the pen tip and nib, writing performance during drying, and dispersion stability of pigments are ensured, which is preferable.

[0025] When manufacturing the aqueous pigment ink composition for writing instruments of the present invention, various conventionally known methods can be adopted. For example, after putting water or bentonite into a stirrer such as a Henschel mixer, propeller stirrer, homogenizer, turbo mixer, high-pressure homogenizer, fine flow mill, etc. having a high shearing force and stirring and dispersing, pigments and other remaining components dispersed by a disperser such as a Henschel mixer, propeller stirrer, homogenizer, turbo mixer, high-pressure homogenizer, ball mill, bead mill, roll mill, etc. are put in, and it can be easily obtained by further mixing and stirring. In addition, in these preparation steps, the generated dispersion heat can be directly utilized for stirring, heating, or cooling and stirring. Removal of bubbles by a defoamer or filtration of coarse substances by a filter may be performed as necessary. These various mixing steps, dispersion steps, filtration steps, heating steps, or cooling steps may be performed alone, or two or more steps may be performed in parallel.

[0026] The aqueous pigment ink composition for writing instruments of the present invention can be suitably used when filled in writing instruments, but is not limited to writing instruments only, and may also be an applicator for cosmetics such as an eyeliner or an eyebrow pencil. Also, a method having a longitudinal cross-section comb-shaped temporary ink reservoir member that directly stores ink without using an ink storage body such as a fiber converging body in the coating liquid storage chamber, or a method having a valve mechanism that automatically opens and closes according to changes in operation or internal pressure may be used. When the aqueous pigment ink composition to be used uses titanium oxide or a large-diameter plate-shaped lustrous pigment, it is preferable to directly store the ink in the coating liquid storage chamber without occluding the ink composition in a fiber converging body called batting, etc., so as to use up the ink stored in the coating liquid storage chamber. Also, as the ink supply mechanism to the application site, rather than one that passes through pores such as a fiber converging body or a longitudinal cross-section comb-shaped temporary ink reservoir member, a ballpoint pen or a pen equipped with a tip valve mechanism that uses a valve mechanism capable of securing a relatively large ink passage to control the ejection of ink with a valve formed at the pen tip is preferable. Furthermore, by using a brush-type application tip that can freely form a wide application mark as desired, a wide application mark exhibiting the luster of the ink can be formed.

[0027] Fig. 1 shows an example of the structure of a writing instrument. A so-called rear-end knock type valve mechanism pen-type applicator that uses a relatively soft one such as a pen tip as the application tip, arranges a valve mechanism at the connection part between the application tip and the coating liquid storage chamber, and opens and closes the valve mechanism by a rear-end knock operation to control the ink supply to the application tip. The tip of the shaft cylinder 1 is provided with an application tip 2, the rear end is provided with a push-type operation part 3, and a cap 4 for protecting the application tip 2 can be fitted to the tip part of the shaft cylinder 1. The cap 4 is provided with a rolling prevention rib 4a on the side wall to prevent the applicator from rolling when the cap 4 is attached. The shaft cylinder 1 has a front shaft 1a having an opening from which the application tip 2 protrudes and a rear shaft 1b to which the operation part 3 is connected.

[0028] The front shaft 1a has a small diameter at the front part on the tip side of the pen tip that matches the diameter of the pen tip, and a large diameter at the rear side that serves as a connection part with the rear shaft 1b. Vertical ribs 5 that support the pen tip are evenly arranged circumferentially on the inner wall of the small diameter part. The groove 6 formed between these vertical ribs 5 also serves as a ventilation path for taking in air of the volume of the ink composition discharged by writing application inside. Further, a valve seat member 7 of a valve mechanism for controlling the ink flow is arranged in the large diameter part at the rear in the front shaft 1a. At the center position of the valve seat member 7, a central hole 7a serving as an ink passage is provided, and the peripheral part thereof is a valve seat that can be circumferentially abutted against a valve rod described later. Also, the valve seat member 7 fixes a coil spring 9 at the rear end that biases the valve rod 8 rearward and keeps it in close contact with the valve seat at all times when not in operation.

[0029] The rear shaft 1b has a rear hole part 10 at the rear end part, and the operation part 3 is arranged. From the rear hole part 10, a connecting rod 11 that transmits the pushing operation of the operation part 3 to the valve rod 8 protrudes, and is liquid-tightly sealed with a packing member 12 made of a material having rubber elasticity and having a flexible hinge part 12a. When the operation part 3 is pushed into the shaft cylinder interior direction, it abuts against the rear end of the packing member 12, and the packing member 12 receives the pushing force and the hinge part 12a deforms to transmit the pushing force to the connecting rod 11. As the connecting rod 11 advances, the valve rod 8 advances against the elastic force of the coil spring 9 and the valve mechanism is released, allowing the ink composition to flow. The coil spring 9 abuts against the tip surface of the connecting rod 11 that becomes the connection step part between the connecting rod 11 and the valve rod 8 and biases the connecting rod 11 and the valve rod 8 rearward. When the pressing operation is released, the connecting rod 11 and the valve rod 8 are moved rearward to close the valve mechanism.

[0030] A coating tip connecting tube 13 is attached to the front end portion of the valve rod 8, and a brush-shaped coating tip 2 is connected to the front end of the coating tip connecting tube 13. Therefore, the coating tip 2 also moves forward in conjunction with the pushing operation of the operation unit 3, and when the pushing operation is released, the coating tip 2 also moves backward by the elastic force of the coil spring 9. By doing so, an external force can be applied to the ink composition existing in the space around the coating tip 2 each time an operation is performed, suppressing drying and solidification, and also assisting in discharging the ink composition. Such a mechanism is particularly effective when using a liquid with a relatively high solid content.

[0031] The inside of the rear shaft 1b mainly serves as a coating liquid storage chamber, and a cylindrical polypropylene volume adjuster 14 for adjusting the volume of the coating liquid storage chamber is arranged so as to surround the connecting rod 11 circumferentially. The volume adjuster 14 may be fixed to the rear shaft 1b, but it is preferably in a non-fixed state that can move back and forth in relation to the operating connecting rod 11. Reducing the volume of the coating liquid storage chamber in this way suppresses the gas-like substances such as the air or the solvent of the ink composition stored inside from expanding due to changes in temperature and pressure and causing the ink composition to blow out when the valve mechanism is opened. Also, by using a transparent or translucent material for the rear shaft, when using a fluorescent pigment or white titanium oxide as a colorant, at least a part of the gap can be narrowed to make it easier to visually recognize the color and remaining amount of the built-in ink composition. Also, by making the color of the volume adjuster 14 black, white, milky white, etc., it is possible to make it even easier to visually recognize the color of the ink composition.

[0032] When attempting to discharge the ink composition by pressing the rear shaft 1b, the rear shaft 1b can be made of a flexible material such as polyolefin resins such as low-density polyethylene, high-density polyethylene, and polypropylene, polyester resins such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate, polyamide, polyacrylonitrile, polycarbonate, polyvinyl chloride, polystyrene, polyoxymethylene, and various elastomers.

Example

[0033] Hereinafter, the present invention will be described in detail by way of examples.

[0034] (Preparation of Ink Composition) Ink compositions of Examples 1 to 281, Comparative Examples 1 to 54, and Reference Examples 1 to 5 were prepared with the formulation compositions shown in Tables 1 to 35 below.

[0035] Specifically, the following materials were used as the materials for the compositions shown in Tables 1 to 35. [Pigment] GP-1: LG neo RED #325 (metallic-coated film powder bright pigment, average particle size 35 μm, manufactured by Oike Imaging Co., Ltd.) GP-2: LG neo GREEN #325 (metallic-coated film powder bright pigment, average particle size 35 μm, manufactured by Oike Imaging Co., Ltd.) GP-3: LG neo BLUE #325 (metallic-coated film powder bright pigment, average particle size 35 μm, manufactured by Oike Imaging Co., Ltd.) GP-4: LG neo YELLOW #325 (metallic-coated film powder bright pigment, average particle size 35 μm, manufactured by Oike Imaging Co., Ltd.) GP-5: LG neo PINK #325 (metallic-coated film powder bright pigment, average particle size 35 μm, manufactured by Oike Imaging Co., Ltd.) GP-6: LG neo B-GOLD #325 (metallic-coated film powder bright pigment, average particle size 35 μm, manufactured by Oike Imaging Co., Ltd.) GP-7: LG neo SILVER #325 (metallic-coated film powder bright pigment, average particle size 35 μm, manufactured by Oike Imaging Co., Ltd.) GP-8: LG neo VIOLET #325 (metallic-coated film powder bright pigment, average particle size 35 μm, manufactured by Oike Imaging Co., Ltd.) GP-9: LG neo R-GOLD #325 (metallic-coated film powder bright pigment, average particle size 35 μm, manufactured by Oike Imaging Co., Ltd.) GP-10: LG neo S-GOLD #325 (Metallic-coated film powder bright pigment, average particle size 35μm, manufactured by Oike Imaging Co., Ltd.) GP-11: LG neo BLACK #325 (Metallic-coated film powder bright pigment, average particle size 35μm, manufactured by Oike Imaging Co., Ltd.) GP-12: LG neo COPPER #325 (Metallic-coated film powder bright pigment, average particle size 35μm, manufactured by Oike Imaging Co., Ltd.) GP-13: LG neo B-GOLD #35 (Metallic-coated film powder bright pigment, manufactured by Oike Imaging Co., Ltd.) GP-14: LG neo GREEN #100 (Metallic-coated film powder bright pigment, average particle size 115μm, manufactured by Oike Imaging Co., Ltd.) GP-15: LG neo GREEN #150 (Metallic-coated film powder bright pigment, average particle size 95μm, manufactured by Oike Imaging Co., Ltd.) GP-16: LG neo YELLOW #150 (Metallic-coated film powder bright pigment, average particle size 95μm, manufactured by Oike Imaging Co., Ltd.) GP-17: LG neo GREEN #200 (Metallic-coated film powder bright pigment, average particle size 60μm, manufactured by Oike Imaging Co., Ltd.) GP-18: LG neo BLUE #200 (Metallic-coated film powder bright pigment, average particle size 60μm, manufactured by Oike Imaging Co., Ltd.) GP-19: LG neo B-GOLD #500 (Metallic-coated film powder bright pigment, average particle size 15μm, manufactured by Oike Imaging Co., Ltd.) CB-1: FUJI SP BLACK 8041 (Black pigment dispersion, carbon black, manufactured by Fuji Pigment Co., Ltd.) CB-2: Carbon Black MA-100 (Carbon black, manufactured by Mitsubishi Chemical Corporation) CB-3: Love Color 220(MD) Black (Acrylic copolymer fine particles, manufactured by Dainichi Seika Chemicals Co., Ltd.) OP-1: FUJI SP BLUE 6555 (Blue pigment dispersion, organic pigment, manufactured by Fuji Pigment Co., Ltd.) OP-2: FUJI SP BLUE 6401 (Cyan Pigment Dispersion, Organic Pigment, manufactured by Fuji Pigment Co., Ltd.) TO-1: CR-50 (Titanium Oxide, manufactured by Ishihara Sangyo Co., Ltd.) JR-1: Rohm & Haas OP-84J (Hollow Resin Particles, manufactured by Rohm and Haas Japan) JR-2: Epotar S6 (Melamine, Benzoguanamine-based Fine Particles, manufactured by Nippon Shokubai Co., Ltd.)

[0036] <Amino Acid Anionic Surfactant Composed of Unsaturated Fatty Acids> UFAA-1: NIKKOL Sarcosinate OH (Oleoyl Sarcosine (Condensate of Oleic Acid and Methylglycine), manufactured by Nikko Chemicals Co., Ltd.) UFAA-2: NIKKOL Sarcosinate OHV (Oleoyl Sarcosine (Condensate of Oleic Acid and Methylglycine), manufactured by Nikko Chemicals Co., Ltd.)

[0037] <Amino Acid Anionic Surfactant Composed of Saturated Fatty Acids> SFAA-1: Amisoft CS-11 (Sodium N-Coconut Oil Fatty Acyl-L-Glutamate, manufactured by Ajinomoto Health Supply Co., Ltd.) SFAA-2: Amisoft CA (N-Coconut Oil Fatty Acyl-L-Glutamate, manufactured by Ajinomoto Health Supply Co., Ltd.) SFAA-3: Amisoft LA-D (N-Lauroyl-L-Glutamic Acid, manufactured by Ajinomoto Health Supply Co., Ltd.) SFAA-4: Amisoft HA-P (N-Stearoyl-L-Glutamic Acid, manufactured by Ajinomoto Health Supply Co., Ltd.) SFAA-5: Amisoft LS-11 (Sodium N-Lauroyl-L-Glutamate, manufactured by Ajinomoto Health Supply Co., Ltd.) SFAA-6: Amisoft MK-11 (Potassium N-Myristoyl-L-Glutamate, manufactured by Ajinomoto Health Supply Co., Ltd.) SFAA-7: Amisoft MS-11 (Sodium N-Myristoyl-L-Glutamate, manufactured by Ajinomoto Health Supply Co., Ltd.) SFAA-8: Amisoft GS-11P (Sodium N-acyl-L-glutamate, manufactured by Ajinomoto Health Supply Co., Ltd.) SFAA-9: Amisoft HS-11P (Sodium N-stearoyl-L-glutamate, manufactured by Ajinomoto Health Supply Co., Ltd.) SFAA-10: Amisoft CT-12 (Aqueous solution of triethanolamine salt of N-coconut fatty acid acyl-L-glutamic acid, manufactured by Ajinomoto Health Supply Co., Ltd.) SFAA-11: Amisoft LT-12 (Aqueous solution of triethanolamine salt of lauroyl-L-glutamic acid, manufactured by Ajinomoto Health Supply Co., Ltd.) SFAA-12: Amisoft CK-22 (Aqueous solution of potassium salt of N-coconut fatty acid acyl-L-glutamic acid, manufactured by Ajinomoto Health Supply Co., Ltd.) SFAA-13: Amisoft CS-22 (Aqueous solution of sodium salt of N-coconut fatty acid acyl-L-glutamic acid, manufactured by Ajinomoto Health Supply Co., Ltd.) SFAA-14: NIKKOL Alaninate LN-30 (30% aqueous solution of sodium lauroylmethylalanine, manufactured by Nikko Chemicals Co., Ltd.) SFAA-15: NIKKOL Sarcosinate CN-30 (30% aqueous solution of sodium cocoyl sarcosinate, manufactured by Nikko Chemicals Co., Ltd.) SFAA-16: NIKKOL Sarcosinate CT-30 (30% aqueous solution of triethanolamine salt of cocoyl sarcosine, manufactured by Nikko Chemicals Co., Ltd.) SFAA-17: NIKKOL Sarcosinate LH (Lauroyl sarcosine, manufactured by Nikko Chemicals Co., Ltd.) SFAA-18: NIKKOL Sarcosinate LN (Sodium lauroyl sarcosinate, manufactured by Nikko Chemicals Co., Ltd.) SFAA-19: NIKKOL Sarcosinate LN-30 (Sodium lauroyl sarcosinate, 30% aqueous solution, manufactured by Nikko Chemicals Co., Ltd.) SFAA-20: NIKKOL Sarcosinate LK-30 (Potassium lauroyl sarcosinate, 30% aqueous solution, manufactured by Nikko Chemicals Co., Ltd.) SFAA-21: NIKKOL Sarcosinate MN (Myristoyl Sarcosine Sodium, manufactured by Nikko Chemicals Co., Ltd.) SFAA-22: NIKKOL Sarcosinate PN (Palmitoyl Sarcosine Sodium, manufactured by Nikko Chemicals Co., Ltd.)

[0038] <Phosphate Ester Type Anionic Surfactant> REA-1: Phosphanol RB-410 (Polyoxyethylene Lauryl Ether Phosphate, manufactured by Toho Chemical Industry Co., Ltd.)

[0039] <Resin Emulsion> EM-1: Eucort UWS-145 (Urethane Resin Emulsion, solid content 35%, manufactured by Sanyo Chemical Industries, Ltd.) EM-2: Eucort UX-300 (Urethane Resin Emulsion, solid content 38%, manufactured by Sanyo Chemical Industries, Ltd.) EM-3: Eucort UX-310 (Urethane Resin Emulsion, solid content 40%, manufactured by Sanyo Chemical Industries, Ltd.) EM-4: Permaline UA-150 (Urethane Resin Emulsion, solid content 30%, manufactured by Sanyo Chemical Industries, Ltd.) EM-5: Permaline UA-200 (Urethane Resin Emulsion, solid content 30%, manufactured by Sanyo Chemical Industries, Ltd.) EM-6: Permaline UA-368 (Urethane Resin Emulsion, solid content 50%, manufactured by Sanyo Chemical Industries, Ltd.) EM-7: Permaline UA-4000 (Urethane Resin Emulsion, solid content 38%, manufactured by Sanyo Chemical Industries, Ltd.) EM-8: Acrit WBR-016U (Urethane Resin Emulsion, solid content 30%, manufactured by Daiso Fine Chemical Co., Ltd.) EM-9: Bonron XGS-001 (Acrylic Resin Emulsion, solid content 45%, manufactured by Mitsui Chemicals, Inc.) EM-10: Bonron XPL-100 (Acrylic Resin Emulsion, solid content 30%, manufactured by Mitsui Chemicals, Inc.) EM-11: Bonron XPL-200 (Acrylic Resin Emulsion, solid content 44%, manufactured by Mitsui Chemicals, Inc.) EM-12: Bonron PS-001 (acrylic resin emulsion, solid content 50%, manufactured by Mitsui Chemicals, Inc.) EM-13: Bonron PS-002 (acrylic resin emulsion, solid content 45%, manufactured by Mitsui Chemicals, Inc.) EM-14: Bonron XPS-004 (acrylic resin emulsion, solid content 45%, manufactured by Mitsui Chemicals, Inc.) EM-15: Bonron XHS-20 (acrylic resin emulsion, solid content 40%, manufactured by Mitsui Chemicals, Inc.) EM-16: Bonron XHS-21S (acrylic resin emulsion, solid content 45%, manufactured by Mitsui Chemicals, Inc.) EM-17: Bonron XHS-50 (acrylic resin emulsion, solid content 20%, manufactured by Mitsui Chemicals, Inc.) EM-18: Bonron S-119H (acrylic resin emulsion, solid content 50%, manufactured by Mitsui Chemicals, Inc.) EM-19: Bonron S-416BF (acrylic resin emulsion, solid content 44.5%, manufactured by Mitsui Chemicals, Inc.) EM-20: Bonron S-415 (acrylic resin emulsion, solid content 44%, manufactured by Mitsui Chemicals, Inc.) EM-21: Bonron S-403 (acrylic resin emulsion, solid content 25%, manufactured by Mitsui Chemicals, Inc.) EM-22: Bonron S-476 (acrylic resin emulsion, solid content 45%, manufactured by Mitsui Chemicals, Inc.) EM-23: Bonron S-1120 (acrylic resin emulsion, solid content 45%, manufactured by Mitsui Chemicals, Inc.) EM-24: Bonron S-483TBF (acrylic resin emulsion, solid content 45%, manufactured by Mitsui Chemicals, Inc.) EM-25: Bonron S-434 (acrylic resin emulsion, solid content 45%, manufactured by Mitsui Chemicals, Inc.) EM-26: Bonron S-1360 (acrylic resin emulsion, solid content 44.5%, manufactured by Mitsui Chemicals, Inc.) EM-27: DM772 (acrylic resin emulsion, solid content 46%, manufactured by Japan Coating Resin Co., Ltd.) EM-28: DM774 (acrylic resin emulsion, solid content 46%, manufactured by Nippon Coating Resin Co., Ltd.) EM-29: Acrit ATW-008S (acrylic resin emulsion, solid content 29.5%, manufactured by Dainippon Fine Chemical Co., Ltd.) EM-30: Joncryl 7100 (acrylic resin emulsion, solid content 48%, manufactured by BASF (Germany)) EM-31: Joncryl 711 (acrylic resin emulsion, solid content 42%, manufactured by BASF (Germany)) EM-32: Joncryl PDX-7370 (acrylic resin emulsion, solid content 42%, manufactured by BASF (Germany)) EM-33: Joncryl PDX-7323 (acrylic resin emulsion, solid content 42%, manufactured by BASF (Germany)) EM-34: Joncryl PDX-7611 (acrylic resin emulsion, solid content 36.5%, manufactured by BASF (Germany)) EM-35: Joncryl 352D (acrylic resin emulsion, solid content 45%, manufactured by BASF (Germany)) EM-36: Joncryl 538J (acrylic resin emulsion, solid content 45%, manufactured by BASF (Germany)) EM-37: Joncryl PDX-7700 (acrylic resin emulsion, solid content 48%, manufactured by BASF (Germany)) EM-38: Joncryl PDX-7177 (acrylic resin emulsion, solid content 36%, manufactured by BASF (Germany)) EM-39: Joncryl 7001 (acrylic resin emulsion, solid content 87%, manufactured by BASF (Germany)) EM-40: Acrit WEM-321U (acrylic-urethane resin emulsion, solid content 38%, manufactured by Dainippon Fine Chemical Co., Ltd.) EM-41: Polyzol S-5J (vinyl acetate resin emulsion, solid content 52%, manufactured by Showa Denko K.K.) EM-42: Polyzol AX-590 (vinyl acetate resin emulsion, solid content 49%, manufactured by Showa Denko K.K.) EM-43: Polyzol AX-751 (vinyl acetate resin emulsion, solid content 46%, manufactured by Showa Denko K.K.) EM-44: Polyzol AX-428J (vinyl acetate resin emulsion, solid content 46%, manufactured by Showa Denko K.K.) EM-45: Polyzol AX-510ZL (vinyl acetate resin emulsion, solid content 43%, manufactured by Showa Denko K.K.) EM-46: Polyzol AX-951 (vinyl acetate resin emulsion, solid content 41%, manufactured by Showa Denko K.K.) EM-47: Polyzol AX-1000 (vinyl acetate resin emulsion, solid content 39%, manufactured by Showa Denko K.K.) EM-48: Polyzol BX-8004 (vinyl acetate resin emulsion, solid content 48%, manufactured by Showa Denko K.K.) EM-49: Polyzol AX-747L (vinyl acetate resin emulsion, solid content 50%, manufactured by Showa Denko K.K.) EM-50: Polyzol P-503 (vinyl acetate resin emulsion, solid content 40%, manufactured by Showa Denko K.K.) EM-51: Polyzol PS-120 (vinyl acetate resin emulsion, solid content 50%, manufactured by Showa Denko K.K.) EM-52: Polyzol S-65 (vinyl acetate resin emulsion, solid content 50%, manufactured by Showa Denko K.K.)

[0040] <Water-soluble resin> WS-1: SMA1440 (water-soluble resin, styrene maleic acid resin, manufactured by Arkema Chemical Co., Ltd.) WS-2: Joncryl52J (styrene acrylic resin aqueous solution, solid content: 60%, manufactured by BASF (Germany)) WS-3: Joncryl62J (water-soluble resin, manufactured by BASF (Germany))

[0041] <Dye> D-1: Water Black 256L (14% aqueous solution of black dye, manufactured by Orient Chemical Industries Co., Ltd.) D-2: Water Red 1 (C.I. Acid Red 18, manufactured by Orient Chemical Industries Co., Ltd.) D-3: Daiwa Red No. 104WB (C.I. Acid Red 92, manufactured by Daiwa Kasei Co., Ltd.) D-4: Daiwa Red No. 106WB (C.I. Acid Red 52, manufactured by Daiwa Kasei Co., Ltd.) D-5: Water Yellow 6C (C.I. Acid Yellow 42, manufactured by Orient Chemical Industries, Ltd.) D-6: Water Blue 119 (manufactured by Orient Chemical Industries, Ltd.) D-7: Daiwa Blue No. 1 (C.I. Acid Blue 9, manufactured by Daiwa Kasei Co., Ltd.)

[0042] <Plate-shaped inorganic compound> BT-1: OPTIGEL-WX (modified bentonite, manufactured by BYK-Chemie Japan Co., Ltd.) BT-2: OPTIGEL-CG (modified bentonite, manufactured by BYK-Chemie Japan Co., Ltd.) BT-3: OPTIGEL-CK (modified bentonite, manufactured by BYK-Chemie Japan Co., Ltd.) BT-4: OPTIGEL-CK XR (modified bentonite, manufactured by BYK-Chemie Japan Co., Ltd.) BT-5: OPTIGEL-CL (modified bentonite, manufactured by BYK-Chemie Japan Co., Ltd.) BT-6: OPTIGEL-CMO (modified bentonite, manufactured by BYK-Chemie Japan Co., Ltd.) BT-7: OPTIGEL-LX (modified bentonite, manufactured by BYK-Chemie Japan Co., Ltd.) BT-8: OPTIGEL-W 724 (modified bentonite, manufactured by BYK-Chemie Japan Co., Ltd.) BT-9: OPTIGEL-WA (modified bentonite, manufactured by BYK-Chemie Japan Co., Ltd.) BT-10: OPTIGEL-WH (modified bentonite, manufactured by BYK-Chemie Japan Co., Ltd.) BT-11: OPTIGEL-WM (modified bentonite, manufactured by BYK-Chemie Japan Co., Ltd.) BT-12: OPTIGEL-WX XR (modified bentonite, manufactured by BYK-Chemie Japan Co., Ltd.) BT-13: Benger (purified bentonite, manufactured by Hoojun Co., Ltd.) BT-14: Benger HV (Purified Bentonite, manufactured by Hoojun Co., Ltd.) BT-15: Benger FA (Purified Bentonite, manufactured by Hoojun Co., Ltd.) BT-16: Benger W-100 (Modified Bentonite, manufactured by Hoojun Co., Ltd.) BT-17: Benger W-100U (Modified Bentonite, manufactured by Hoojun Co., Ltd.) BT-18: Esben NX (Purified Bentonite, manufactured by Hoojun Co., Ltd.) BT-19: Kunipia-F (Purified Bentonite, manufactured by Kunimine Co., Ltd.) BT-20: Kunipia-G (Purified Bentonite, manufactured by Kunimine Co., Ltd.) BT-21: Moistnite-U (Bentonite, manufactured by Kunipia Co., Ltd.) ST-1: LAPONITE-RD (Synthetic Hectorite, manufactured by BYK-Chemie Japan Co., Ltd.) ST-2: LAPONITE-EP (Synthetic Hectorite, manufactured by BYK-Chemie Japan Co., Ltd.) ST-3: LAPONITE-RDS (Synthetic Hectorite, manufactured by BYK-Chemie Japan Co., Ltd.) ST-4: LAPONITE-JS (Synthetic Hectorite, manufactured by BYK-Chemie Japan Co., Ltd.) ST-5: LAPONITE-S482 (Synthetic Hectorite, manufactured by BYK-Chemie Japan Co., Ltd.) ST-6: Smeton-SA (Synthetic Saponite, manufactured by Kunimine Co., Ltd.) ST-7: Smeton-ST (Synthetic Stevansite, manufactured by Kunimine Co., Ltd.) ST-8: Smeton-SWN (Synthetic Hectorite, manufactured by Kunimine Co., Ltd.) ST-9: Smeton-SWF (Synthetic Hectorite, manufactured by Kunimine Co., Ltd.)

[0043] <Polysaccharide> GM-1: Kelcocrete200 (Diyutan Gum, manufactured by Sankei Co., Ltd.) GM-2: Kelzan (Xanthan Gum, manufactured by Sankei Co., Ltd.) GM-3: MEYPRO-GAT (Guar Gum, manufactured by Sankei Co., Ltd.) GM-4: K1A96 (manufactured by Wellangam, Sankeikagaku Co., Ltd.) GM-5: Maprodin 200 (locust bean gum, manufactured by Sankeikagaku Co., Ltd.) GM-6: GENU pectin type BETA (pectin, manufactured by Sankeikagaku Co., Ltd.) GM-7: Reosan (sucsinoglycan, manufactured by Sankeikagaku Co., Ltd.)

[0044] <Main solvent> W-1: Ion-exchanged water

[0045] <Organic solvent> SOL-1: Diethylene glycol SOL-2: Ethylene glycol SOL-3: Glycerin SOL-4: 3-Methyl-3-methoxy-1-butanol SOL-5: Diethylene glycol monomethyl ether SOL-6: Propylene glycol

[0046] <Wax emulsion> WEM-1: RK-185 (paraffin wax, manufactured by Gohou Chemical Industry Co., Ltd.) WEM-2: WE-65 (paraffin wax, manufactured by Konishi Co., Ltd.) WEM-3: Chemparl W900 (polyethylene wax, manufactured by Mitsui Chemicals, Inc.) WEM-4: Chemparl A100 (ethylene·α-olefin copolymer, manufactured by Mitsui Chemicals, Inc.) WEM-5: Chemparl V100 (ethylene vinyl acetate copolymer resin, manufactured by Mitsui Chemicals, Inc.)

[0047] <Mildew preventive> AM―1: Proxel GXL(S) (mildew preventive, manufactured by Lonza Japan Co., Ltd.) AM―2: Proxel GXL (mildew preventive, manufactured by Lonza Japan Co., Ltd.) AM―3: Sun Eye Back Sodium Omadine (mildew preventive, manufactured by San-Ai Sekiyu Co., Ltd.)

[0048] <Rust preventive> RI-1: Benzotriazole (rust inhibitor, manufactured by E-CHEM ENTERPRISE CORPORATION)

[0049] <pH adjuster> PC-1: NaOH PC-2: Triethanolamine PC-3: Diethanolamine PC-4: Aminomethylpropanol The ink compositions of each example, comparative example, and reference example were prepared as follows.

[0050] <Examples 1 to 281, Reference Examples 1 to 5> The total amount of the amino acid anionic surfactant composed of unsaturated fatty acids, the total amount of the amino acid anionic surfactant composed of saturated fatty acids, the total amount of ion-exchanged water as the main solvent, and the total amount of the organic solvent were stirred with a homomixer for 1 hour to prepare an aqueous solution of the amino acid anionic surfactant. Then, the total amount of the pigment was added and stirred with a homomixer for 1 hour. Thereafter, the total amount of the remaining formulations was added and stirred with a homomixer for 1 hour to obtain an ink composition.

[0051] <Comparative Examples 1 to 4, 51> The total amount of ion-exchanged water as the main solvent, the total amount of the organic solvent, and the total amount of the pigment were added and stirred with a homomixer for 1 hour. Then, the total amount of the remaining formulations was added and stirred with a homomixer for 1 hour to obtain an ink composition.

[0052] <Comparative Examples 5 to 14> The total amount of the phosphate ester type anionic surfactant, the total amount of ion-exchanged water as the main solvent, and the total amount of the organic solvent were stirred with a homomixer for 1 hour to prepare an aqueous solution of the phosphate ester type anionic surfactant. Then, the total amount of the pigment was added and stirred with a homomixer for 1 hour. Thereafter, the total amount of the remaining formulations was added and stirred with a homomixer for 1 hour to obtain an ink composition.

[0053] <Comparative Examples 15 to 38> The total amount of the amino acid anion surfactant composed of saturated fatty acids, the total amount of ion-exchanged water as the main solvent, and the total amount of the organic solvent were stirred with a homomixer for 1 hour to prepare an aqueous solution of the amino acid anion surfactant. Then, the total amount of the pigment was added and stirred with a homomixer for 1 hour. Thereafter, the total amount of the remaining formulation was added and stirred with a homomixer for 1 hour to obtain an ink composition.

[0054] <Comparative Examples 39 to 50, 52 to 54> The total amount of the amino acid anion surfactant composed of unsaturated fatty acids, the total amount of ion-exchanged water as the main solvent, and the total amount of the organic solvent were stirred with a homomixer for 1 hour to prepare an aqueous solution of the amino acid anion surfactant. Then, the total amount of the pigment was added and stirred with a homomixer for 1 hour. Thereafter, the total amount of the remaining formulation was added and stirred with a homomixer for 1 hour to obtain an ink composition.

[0055] (Content of each amino acid anion surfactant) In the table of the examples, the content of the amino acid anion surfactant composed of unsaturated fatty acids with respect to the content of the total amino acid anion surfactant in the ink composition (denoted as "UFAA(%)" in the table of the examples. The unit is "wt%") and the content of the amino acid anion surfactant composed of saturated fatty acids with respect to the content of the total amino acid anion surfactant in the ink composition (denoted as "SFAA(%)" in the table of the examples. The unit is "wt%") were described.

[0056] Ink backflow prevention composition 1 Lucant HC100 (ethylene Α olefin, base material, manufactured by Mitsui Petrochemical Industries, Ltd.) 94.5 wt% Aerosil R974 (fine particle silica, gelling agent, manufactured by Nippon Aerosil Co., Ltd.) 4.0 wt% Leopar KL (dextrin fatty acid ester, manufactured by Chiba Flour Milling Co., Ltd.) 1.5 wt% The above components were mixed and stirred at 150 °C for 2 hours with a hot stirrer to obtain Ink backflow prevention composition 1. The viscosity of this Ink backflow prevention composition 1 at 25 °C was 40000 mPa·S.

[0057] (Preparation of the test writing instrument 1) To evaluate the ink compositions according to the examples and comparative examples, a brush pen type applicator with a rear-end knock valve mechanism shown in FIG. 1 for testing was prepared. Then, 2.0 g of the aqueous pigment ink compositions for writing instruments of Examples 1 to 278, Comparative Examples 1 to 51, and Reference Examples 1 to 5 were filled therein to obtain the test writing instrument 1. (In the table, it is denoted as "writing instrument 1", and "〇" is denoted in the column of the corresponding combination)

[0058] (Preparation of the test writing instrument 2) To evaluate the ink compositions according to the examples and comparative examples, 2.0 g of the aqueous pigment ink compositions for writing instruments of Example 279 and Comparative Example 52 were filled into a commercially available paint marker (excluding the ink from MMP20-A (manufactured by Pentel Co., Ltd.)) to obtain the test writing instrument 2. (In the table, it is denoted as "writing instrument 2", and "〇" is denoted in the column of the corresponding combination)

[0059] (Preparation of the test writing instrument 3) To evaluate the ink compositions according to the examples and comparative examples, 2.0 g of the aqueous pigment ink compositions for writing instruments prepared in Example 280 and Comparative Example 53 were directly filled into a commercially available correction fluid applicator (XEZL61-W, manufactured by Pentel Co., Ltd.) excluding the correction fluid to obtain the test writing instrument 3. (In the table, it is denoted as "writing instrument 3", and "〇" is denoted in the column of the corresponding combination)

[0060] (Preparation of the test writing instrument 4) To evaluate the ink compositions according to the examples and comparative examples, 0.8 g of the aqueous pigment ink compositions for writing instruments of Example 281 and Comparative Example 54 and 0.1 g of the ink backflow prevention composition 1 were directly filled into a commercially available aqueous ballpoint pen (K110-DX, manufactured by Pentel Co., Ltd.) excluding the ink and the ink backflow prevention composition to obtain the test writing instrument 4. (In the table, it is denoted as "writing instrument 4", and "〇" is denoted in the column of the corresponding combination)

[0061] (Low-temperature writing test 1 after low-temperature storage) The capped test sample was left lying on its side in an environmental testing room at room temperature -5°C for three months. While still in the -5°C environment, the cap was removed from the test sample and the character "長" (long) measuring 2cm x 2cm was written on test paper specified in 7.3 of JIS S 6061. It was confirmed that the ink was ejected and a good handwriting was formed. 〇: Can be written well. ×: Unable to write.

[0062] (Low temperature written test 2 after low temperature storage) The capped test sample was left lying on its side in an environmental testing room at room temperature -5°C for four months. While still in the -5°C environment, the cap was removed from the test sample and the character "長" (long) measuring 2cm x 2cm was written on test paper specified in 7.3 of JIS S 6061. It was confirmed that the ink was ejected and a good handwriting was formed. 〇: Can be written well. ×: Unable to write.

[0063] (Low temperature written test 3 after low temperature storage) The capped test sample was left lying on its side in an environmental testing room at room temperature -5°C for five months. While still in the -5°C environment, the cap was removed from the test sample and the character "長" (long) measuring 2cm x 2cm was written on test paper specified in 7.3 of JIS S 6061. It was confirmed that the ink was ejected and a good handwriting was formed. 〇: Can be written well. ×: Unable to write.

[0064] (Low temperature written test 4 after low temperature storage) The capped test sample was left lying on its side in an environmental testing room at room temperature -5°C for six months. While still in the -5°C environment, the cap was removed from the test sample and the character "長" (long) measuring 2cm x 2cm was written on the test paper specified in 7.3 of JIS S 6061. It was confirmed that the ink was ejected and a good handwriting was formed. 〇: Can be written well. ×: Unable to write.

[0065] (Measurement of physical properties) For Examples 1 to 281, Comparative Examples 1 to 54, and Reference Examples 1 to 5 obtained as described above, the following physical property values were measured. The measured physical property values and measurement methods are as follows. The measurement results of each physical property value are shown in Tables 1 to 35 below.

[0066] <ph> The pH (denoted as pH in the table) of the ink compositions of each example and comparative example was measured. The above pH measurement was performed using "pH METER D-52" manufactured by HORIBA at a temperature of 25°C. The pH of the ink composition is preferably 6.0 to 10.0, and more preferably 7.0 to 9.0. If the pH of the aqueous pigment ink composition for writing instruments is within the above numerical range, it becomes easier to form a bond between the amino acid anionic surfactant composed of unsaturated fatty acid and the pigment surface of the amino acid anionic surfactant composed of saturated fatty acid, and it is possible to expect the maintenance of the fluidity of the aqueous pigment ink composition for writing instruments over a long period. <Viscosity> The viscosity (denoted as viscosity @16.0 in the table) at a temperature of 25°C and a shear rate of 16.0 / s of each example and comparative example was measured. The unit of the measurement results shown in the table is [mPa·s]. The above viscosity measurement was performed using "MCR-302" manufactured by Anton Paar, and the measurement conditions were to measure the viscosity at a temperature of 25°C and a 50 mm cone plate (1°).

[0067]

Table 1

[0068]

Table 2

[0069]

Table 3

[0070]

Table 4

[0071]

Table 5

[0072]

Table 6

[0073]

Table 7

[0074]

Table 8

[0075]

Table 9

[0076]

Table 10

[0077]

Table 11

[0078]

Table 12

[0079]

Table 13

[0080]

Table 14

[0081]

Table 15

[0082]

Table 16

[0083]

Table 17

[0084]

Table 18

[0085]

Table 19

[0086]

Table 20

[0087]

Table 21

[0088]

Table 22

[0089]

Table 23

[0090]

Table 24

[0091]

Table 25

[0092]

Table 26

[0093]

Table 27

[0094]

Table 28

[0095]

Table 29

[0096]

Table 30

[0097]

Table 31

[0098]

Table 32

[0099]

Table 33

[0100]

Table 34

[0101]

Table 35

[0102] The aqueous pigment ink compositions for writing instruments of Examples 1 to 281 were allowed to stand in an environmental test chamber at room temperature - 5°C for more than 3 months, and they flowed, the ink was sufficiently ejected, and the formation of writing was good.

[0103] In contrast, in Comparative Examples 1 to 54, since an amino acid anionic surfactant composed of an unsaturated fatty acid and an amino acid anionic surfactant composed of a saturated fatty acid were not used in combination, when left standing in an environmental test chamber at room temperature - 5°C for 3 months or more, the ink composition did not flow and writing was impossible. In addition, as in Comparative Examples 15 to 38, even when only the amino acid anionic surfactant composed of a saturated fatty acid was added, when left standing in an environmental test chamber at room temperature - 5°C for 3 months or more, the ink composition did not flow and writing became impossible. As in Comparative Examples 37 to 38, even when a plurality of types of amino acid anionic surfactants composed of saturated fatty acids were used in combination, when left standing in an environmental test chamber at room temperature - 5°C for 3 months or more, the ink composition did not flow and writing became impossible. Further, as in Comparative Examples 39 to 50 and 52 to 54, even when only the amino acid anionic surfactant composed of an unsaturated fatty acid was added, when left standing in an environmental test chamber at room temperature - 5°C for 3 months or more, the ink composition did not flow and writing became impossible.

[0104] As described above, the embodiments of the present invention have been described. However, the present invention is not limited to the above-described embodiments, and also includes forms in which modifications are made to the above-described embodiments and forms in which these forms are appropriately combined.

[0105] In this specification, expressions indicating that things such as "identical", "equal", and "homogeneous" are in an equal state represent not only a strictly equal state but also a state in which there are tolerances or differences to the extent that the same function can be obtained. Further, in this specification, the expression that one component "comprises", "includes", or "has" is not an exclusive expression that excludes the existence of other components.

Explanation of Reference Numerals

[0106] 1 Shaft cylinder 1a Front shaft 1b Rear shaft 2 Application tip 3 Operation part 4 Cap 4a Anti-rolling rib 5 Vertical rib 6 Groove 7 Valve seat member 7a Central hole 8 Valve stem 9 Coil spring 10 Rear hole part 11 Connecting rod 12 Packing member 12a Hinge part 13 Coating destination connecting pipe 14 Volume adjuster< / ph>

Claims

1. The aqueous pigment ink composition for a writing instrument comprises at least a pigment, an amino acid anionic surfactant composed of an unsaturated fatty acid, an amino acid anionic surfactant composed of a saturated fatty acid, a resin emulsion, a plate-like inorganic compound, and water, and the content of each of the amino acid anionic surfactant composed of an unsaturated fatty acid and the amino acid anionic surfactant composed of a saturated fatty acid is 20% by weight or more relative to the total amino acid anionic surfactant content of the ink composition.

2. 2. The aqueous pigment ink composition for writing instruments according to claim 1, wherein the content of each of the amino acid anionic surfactant consisting of an unsaturated fatty acid and the amino acid anionic surfactant consisting of a saturated fatty acid is 30% by weight or more relative to the total amino acid anionic surfactant content of the ink composition.

3. An aqueous pigment ink composition for a writing instrument comprising at least a pigment, an amino acid anionic surfactant composed of an unsaturated fatty acid, an amino acid anionic surfactant composed of a saturated fatty acid, a resin emulsion, a plate-like inorganic compound, and water, the content of the pigment being 0.5% by weight or more and 20% by weight or less based on the total weight of the ink composition, and the content of each of the amino acid anionic surfactant composed of an unsaturated fatty acid and the amino acid anionic surfactant composed of a saturated fatty acid being 10% by weight or more based on the total amino acid anionic surfactant content of the ink composition.

4. 4. The aqueous pigment ink composition for writing instruments according to claim 3, wherein the content of the pigment is from 1.0% by weight to 10.0% by weight based on the total amount of the ink composition.

5. An aqueous pigment ink composition for a writing instrument comprising at least a pigment, an amino acid anionic surfactant composed of an unsaturated fatty acid, an amino acid anionic surfactant composed of a saturated fatty acid, a resin emulsion, a plate-like inorganic compound, and water, wherein the average particle size of the pigment is 10 μm or more and 115 μm or less, and the content of each of the amino acid anionic surfactant composed of an unsaturated fatty acid and the amino acid anionic surfactant composed of a saturated fatty acid is 10 weight % or more relative to the total amino acid anionic surfactant content of the ink composition.

6. 6. The aqueous pigment ink composition for writing instruments according to claim 5, wherein the average particle size of the pigment is 30 μm or more and 115 μm or less.

7. The aqueous pigment ink composition for a writing instrument comprises at least a pigment, an amino acid anionic surfactant composed of an unsaturated fatty acid, an amino acid anionic surfactant composed of a saturated fatty acid, a resin emulsion, a plate-like inorganic compound, and water, the pigment being a luster pigment, and the content of each of the amino acid anionic surfactant composed of an unsaturated fatty acid and the amino acid anionic surfactant composed of a saturated fatty acid is 10% by weight or more relative to the total amino acid anionic surfactant content of the ink composition.

8. 8. The aqueous pigment ink composition for writing instruments according to claim 7, wherein the average particle size of the glittering pigment is from 10 μm to 115 μm.

9. 9. The aqueous pigment ink composition for a writing instrument according to claim 8, wherein the average particle size of the glittering pigment is 30 μm or more and 115 μm or less.

10. The aqueous pigment ink composition for a writing instrument according to claim 7 , further comprising at least a dye.

11. The aqueous pigment ink composition for a writing instrument comprises at least two or more types of pigments, an amino acid anionic surfactant composed of an unsaturated fatty acid, an amino acid anionic surfactant composed of a saturated fatty acid, a resin emulsion, a plate-like inorganic compound, and water, and the content of each of the amino acid anionic surfactant composed of an unsaturated fatty acid and the amino acid anionic surfactant composed of a saturated fatty acid is 10% by weight or more relative to the total amino acid anionic surfactant content of the ink composition.

12. The aqueous pigment ink composition for a writing instrument comprises at least a pigment, a dye, an amino acid anionic surfactant composed of an unsaturated fatty acid, an amino acid anionic surfactant composed of a saturated fatty acid, a resin emulsion, a plate-like inorganic compound, and water, and the content of each of the amino acid anionic surfactant composed of an unsaturated fatty acid and the amino acid anionic surfactant composed of a saturated fatty acid is 10% by weight or more relative to the total amino acid anionic surfactant content of the ink composition.

13. An aqueous pigment ink composition for a writing instrument comprising at least a pigment, an amino acid anionic surfactant composed of an unsaturated fatty acid, an amino acid anionic surfactant composed of a saturated fatty acid, a resin emulsion, a plate-like inorganic compound, and water, wherein the total content of the amino acid anionic surfactants is 0.1% by weight or more and 5.0% by weight or less based on the total amount of the ink composition, and the content of each of the amino acid anionic surfactant composed of an unsaturated fatty acid and the amino acid anionic surfactant composed of a saturated fatty acid is 10% by weight or more based on the total amount of the amino acid anionic surfactants in the ink composition.

14. An aqueous pigment ink composition for a writing instrument comprising at least a pigment, an amino acid anionic surfactant composed of an unsaturated fatty acid, an amino acid anionic surfactant composed of a saturated fatty acid, a resin emulsion, a plate-like inorganic compound, and water, the content of the resin emulsion being 1.0% by weight or more and 10.0% by weight or less based on the total amount of the ink composition, and the content of each of the amino acid anionic surfactant composed of an unsaturated fatty acid and the amino acid anionic surfactant composed of a saturated fatty acid being 10% by weight or more based on the total amount of amino acid anionic surfactant in the ink composition.

15. An aqueous pigment ink composition for a writing instrument comprising at least a pigment, an amino acid anionic surfactant composed of an unsaturated fatty acid, an amino acid anionic surfactant composed of a saturated fatty acid, a resin emulsion, a plate-like inorganic compound, and water, wherein the content of the plate-like inorganic compound is 0.05% by weight or more and 3.0% by weight or less based on the total amount of the ink composition, and the content of each of the amino acid anionic surfactant composed of an unsaturated fatty acid and the amino acid anionic surfactant composed of a saturated fatty acid is 10% by weight or more based on the total amount of amino acid anionic surfactant in the ink composition.

16. 16. The aqueous pigment ink composition for writing instruments according to claim 15, wherein the content of the plate-like inorganic compound is 0.1% by weight or more and 2.0% by weight or less based on the total amount of the ink composition.

17. 17. The aqueous pigment ink composition for a writing instrument according to claim 15 or 16, wherein the plate-like inorganic compound is bentonite.

18. A writing instrument or applicator that contains an aqueous pigment ink composition for a writing instrument as a coating liquid in a coating liquid storage chamber, the aqueous pigment ink composition comprising at least a pigment, an amino acid anionic surfactant composed of an unsaturated fatty acid, an amino acid anionic surfactant composed of a saturated fatty acid, a resin emulsion, a plate-like inorganic compound, and water, wherein the content of each of the amino acid anionic surfactant composed of an unsaturated fatty acid and the amino acid anionic surfactant composed of a saturated fatty acid is 10% by weight or more relative to the total amino acid anionic surfactant content of the ink composition, and that is capable of being ejected from an application destination.

19. 19. The writing instrument or applicator according to claim 18, wherein the writing instrument is any one of a marking pen, a brush pen, a ballpoint pen, and a correction fluid applicator.

20. 19. The writing or applicator instrument of claim 18, wherein the applicator instrument is either an eyeliner or an eyebrow applicator.

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