JP4289196B2 - Water-based ink for ballpoint pens - Google Patents

Description

  The present invention comprises a ball holder that rotatably holds a ball as a writing member that directly contacts a writing member such as a paper surface to form a handwriting, and ink attached to the ball is transferred to the writing surface. It is related with the water-based ink which uses the water used for what is called a ball-point pen which forms a writing line as a main medium.

  Ballpoint pens are used in many cases because they provide a relatively thin handwriting, and unlike writing instruments that have a fiber nib or resin nib, there is little change in the handwriting width due to crushing of the nib even when used for a long time. Has been. A low-viscosity water-based ink used for such a ballpoint pen is easy to flow as it is and causes ink leakage. Therefore, a fiber bundling body is used as an ink occlusion body to hold the ink. By making the viscosity high, it is possible to prevent ink leakage without using an ink occlusion body, but it becomes difficult to eject ink for writing, so shearing viscosity is given and the writing member As described above, there is known a technique in which viscosity is temporarily lowered by a shearing force generated by the rotation of a ball and ink is made to flow and ejected (see Patent Document 1).

In addition, in order to prevent ink leakage, polymer dye emulsion and latex particles are added, and the gap between the ball and ball holder in the ballpoint pen tip is closed by a dry film formed by these emulsions to prevent ink leakage. Proposals for blocking have been made (see Patent Documents 2 and 3).
JP 59-74175 JP 59-140273 A JP 58-176281 A

  Even if the ink is shear thinning, depending on the non-writing viscosity setting, ink leakage cannot be suppressed, and if the viscosity is high enough to prevent ink leakage, the ink around the ball will flow when written. Since the ink in the ink tank hardly flows and does not follow, the ink discharge is eventually hindered, and the writing line may be discontinuous. In addition, when a polymer dye emulsion or latex particles are added, the effect under high humidity conditions where a dry film is difficult to be formed cannot be expected.

The present invention includes at least a colorant, water, a shear thinning agent, and a polymer water absorbent swelled in a spherical shape. After the shear thinning agent is dissolved in water, the polymer water absorbent is added. A gist of a method for producing a water-based ink for a ballpoint pen .

  The polymer water-absorbing body of the present invention takes water into the inside and swells in a spherical shape, and is spherically deposited between the ball and the ball holder so as to function as a plug. Inferred. The plug formed by the accumulation of the spherical swelling particles has a strength enough to stop the flow of the ink, but it easily collapses by the rotation of the ball by writing and does not inhibit the ink discharge. The polymer water-absorbing body swells with the moisture in the ink, so that it can prevent leakage even in a humid environment, and the ink viscosity when not writing can be set to a relatively low viscosity, thus inhibiting ink ejection during writing. A continuous handwriting can be obtained.

  This will be described in detail below. As the colorant used in the present invention, dyes and pigments used in conventional water-based inks can be used. As the dye, any of acid dyes, direct dyes, basic dyes, and the like can be used. For example, Japanol Fast Black D Conch (CI Direct Black 17), Water Black 100L (19), Water Black L-200 (19), Direct Fast Black B (22), Direct Fast Black AB (32), Direct Deep Black EX (38), Direct Fast Black Conk (51), Kayala Spragley VGN (71), Kayalas Direct Brilliant Yellow G (CI Direct Yellow 4) ), Direct Fast Yellow 5GL (26), Eisen Primula Yellow GCLH (44), Direct Fast Yellow R (50), Eisen Direct Fast Red FH (CI Direct Red 1), Nippon Fast Scarlet G X (4), Direct Fast Scarlet 4BS (23), Eisen Direct Rhodulin BH (31), Direct Scarlet B (37), Kayak Direct Scarlet 3B (39), Eisen Primula Pink 2BLH (75) ), Sumilite Red F3B (80), Eisen Primula Red 4BH (81), Kayara Spral Bin BL (83), Kayara Light Red F5G (225), Kayara Light Red F5B (226), Caillas Light Rose FR (same as 227), Direct Sky Blue 6B (CI Direct Blue 1), Direct Sky Blue 5B (same as 15), Sumilite Splash Blue BRR Conch (same as 71), Dibogen Turquoise Blue S 86), Water Blue # 3 (same as above) 6), direct dyes such as Kayala Star Coyze Blue GL (86), Kayala Supra Blue FF2GL (106), Kayara Supra Turquoise Blue FBL (199), Acid Blue Black 10B (CI Acid Black) 1), Nigrosine (2), Suminol Milling Black 8BX (24), Kayanol Milling Black VLG (26), Suminol Fast Black BR Conk (31), Mitsui Nylon Black GL (52), Eisen Opal Black WH Extra Conk (52), Sumilan Black WA (52), Ranil Black BG Extra Conk (107), Kyanol Milling Black TLB (109), Suminol Milling Black B (109), Kaya NORMILLING BLACK TLR ( 110), Eisen Opal Black New Conque (119), Water Black 187-L (154), Kayaku Acid Brilliant Flavin FF (C.I. I. Acid Yellow 7: 1), Kayasil Yellow GG (17), Xylene Light Yellow 2G 140% (17), Suminol Leveling Yellow NR (19), Daiwa Tarrazine (23), Kayaktor Torazin (23) , Suminol Fast Yellow R (25), Diacid Light Yellow 2GP (29), Suminoll Milling O O (38), Suminol Milling MR MR (42), Water Yellow # 6 (42), Kayanol Yellow NFG (49), Suminol Milling Yellow 3G (72), Suminol Fast Yellow G (61), Suminol Milling Yellow G (78), Kayanol Yellow N5G (110), Suminol Milling Yellow 4G 200% (same 141), Kayanor Yellow NG (same 135), Kayano Lumiling Yellow 5GW (127), Kayanol Milling 6GW (142), Sumitomo Fast Scarlet A (CI Acid Red 8), Kayak Silk Scarlet (9), Solar Rubin Extra (14), Daiwa New Coxin (18), Eisenbonso RH (26), Daiwa Red No. 2 (27), Suminol Leveling Brilliant Red S3B (35), Kayasil Rubinol 3GS (37), Eisen Erythrosin ( 51), kayak acid rhodamine FB (52), Suminol leveling rubinol 3GP (57), diacid alizarin rubinol F3G 200% (82), Eiseneosin GH (87), water pink # 2 (same) 92), Eisen Acid Phloxin PB 92), Rose Bengal (94), Cyanol Milling Scarlet FGW (111), Cyanol Milling Lubin 3BW (129), Sinoall Milling Brilliant Red 3BN Conch (131), Suminol Milling Brilliant Red BS ( 138), Eisen Opal Pink BH (186), Suminoll Milling Brilliant Red B Conch (249), Kayaku Acid Brilliant Red 3BL (254), Kayaku Acid Brilliant Red Brilliant Red BL (265), Kayanol Milling Red GW (276), Mitsui Acid Violet 6BN (CI Acid Violet 15), Mitsui Acid Violet BN (17), Sumitomo Patent Pure Blue VX (CI Acid Blue) 1), Water Blue # 106 (same 1), Patent Blue AF (same 7), Water Blue # 9 (same 9), Daiwa Blue 1 (same 9), Spranol Blue B (same 15), Orient Solve Blue OBC (22), Suminol Leveling Blue 4GL (23), Mitsui Nylon Fast Blue G (25), Kayasil Blue AGG (40), Kayasil Blue BR (41), Mitsui Alizarin Saphirol SE (43) , Suminol Leveling Sky Blue R Extra Conc (62), Mitsui Nylon Fast Sky Blue B (78), Sumitomo Brilliant Indocyanine 6Bh / c (83), Sandlancyanine N-6B 350% (90), Water Blue # 115 (90), Orient Soluble Blue OBB The same 93), Sumitomo brilliant blue 5G (the 103), Kaya Nord milling Ultra Sky SE (the 112), Kaya Nord milling cyanine 5R (the 113), Aizen Opal Blue 2GLH (the 158), Daiwa Guinea green B (C. I. Acid Green 3), Acid Brilliant Milling Green B (same 9), Daiwa Green # 70 (same 16), Cyanol Cyanine Green G (same 25), Suminol Milling Green G (same 27), etc. Ron Yellow 3GLH (CI Basic Yellow 11), Eisen Cachiron Brilliant Yellow 5GLH (13), Sumiacryl Yellow E-3RD (15), Maxilon Yellow 2RL (19), Astrazone Yellow 7GLL (same) 21), Kayacrill Golden Yellow GL-ED (same 28), Astrazone Yellow 5GL (same 51), Eisen Cachilon Orange GLH (CI Basic Orange 21), Eisen Katyron Brown 3GLH (same 30), Rhodamine 6 GCP (C.I. Cred 1), Eisen Astrafloxin (12), Sumiacryl Brilliant Red E-2B (15), Astrazone Red GTL (18), Eisen Cathlon Brilliant Pink BGH (27), Maxilon Red GRL (same) 46), Eisenmethyl Violet (CI Basic Violet 1), Eisen Crystal Violet (Same 3), Eisen Rhodamine B (Same 10), Astrazone Blue G (CI Basic Blue 1), Astrazone Blue BG (Same 3), methylene blue (same 9), maxilon blue GRL (same 41), Eisen Cachiron blue BRLH (same 54), Eisen Diamond Green GH (CI Basic Green 1), Eisen Malachite Green (same 4) ), Bismarck Blau G include basic dye (C.I. Basic Brown 1) and the like.

  As pigments, organic pigments such as azo pigments, nitroso pigments, nitro pigments, basic dye pigments, acidic dye pigments, building dye pigments, mordant dye pigments, and natural dye pigments, ocher, barium Examples thereof include inorganic pigments such as yellow, bitumen, cadmium red, barium sulfate, titanium oxide, petiole, iron black, and carbon black, and these can be used alone or in combination. Specific examples include aniline black (CI 50440), cyanine black, naphthol yellow S (CI 10316), Hansa Yellow 10G (CI 11710), Hansa Yellow 5G (CI 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. 11740), 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 Aero NCG (C.I. 20040), Balkan Fastoe -5G (C.I. 21220), Vulcan Fast Yellow R (C.I. 21135), Tartrazine Lake (C.I. 19140), Quinoline Yellow Lake (C.I. 47005), Anslagen Yellow 6GL (C I.60520), permanent yellow FGL, permanent yellow H10G, permanent yellow HR, anthrapyrimidine yellow (CI 68420), Sudan I (CI 12055), permanent orange (CI 12075), resole 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 ole Di (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) ), Parachlor ortho aniline red (C.I. 12090), resol fast scarlet, brilliant fast scarlet (C.I. 12315), brilliant carmine BS, permanent red F2R (C.I. 12310), permanent red F4R (C I.1 2335), permanent red FRL (C.I. I. 12440), Permanent Red FRLL (C.I. 12460), Permanent Red F4RH (C.I. 12420), Fast Scarlet VD, Vulcan Fast Rubin 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), Resol Red (C.I. 15630), Lake Red C (C.I. 15585), Lake Red D (C.I. 15500), Anthosine B (C.I. 18030), Brilliant Scarlet G (C.I. 15800), Risol rubin GK (C.I.158) 5), 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 Perm. Bordeaux F2R (C.I. 12385), Helio Bordeaux BL (C.I. 14830), Bordeaux 10B (C.I. 15880), Bon Maroon Light (C.I. 15825), Bonn 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 Rune (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, Alkaline 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), Indance Ren Blue BC (C.I.6 9825), Indigo (C.I. 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), Examples include phthalocyanine green. The amount of these colorants used is preferably 0.5 to 30% by weight based on the total amount of ink. If it is less than 0.5% by weight, it may be thin and not perform as a handwriting. If it exceeds 30% by weight, the ink inside the ball holder tends to be easily dried.

When a pigment is used as the colorant, a dispersant may be used to stably disperse the pigment. As the dispersant, those used as pigment dispersants such as water-soluble resins or water-soluble resins or anionic or nonionic surfactants generally used can be used. Examples of the polymer dispersant include natural polymers such as lignin sulfonate and shellac, polyacrylate, salt of styrene-acrylic acid copolymer, salt of vinylnaphthalene-maleic acid copolymer, β-naphthalene Examples thereof include anionic polymers such as sodium salt and phosphate of sulfonic acid formalin condensate, and nonionic polymers such as polyvinyl alcohol and polyethylene glycol. In addition, as surfactants, alkyl sulfates, polyoxyethylene alkyl ether sulfates, N-acyl amino acids and salts thereof, N-acyl methyl taurine salts, polyoxyethylene alkyl ether acetates, alkyl sulfocarboxylates, α- Nonionic surfactants such as olefin sulfonates, alkyl phosphates, polyoxyethylene alkyl ether phosphates, polyoxyethylene alkyl ethers, sorbitan alkyl esters, polyoxyethylene sorbitan alkyl esters Surfactant is mentioned.
These water-soluble resins and surfactants may be used alone or in combination of two or more. The amount used is preferably 0.05 to 20 parts by weight with respect to 10 parts by weight of the pigment. When the amount is less than 0.05 parts by weight, the dispersion effect, which is the purpose of addition, is weak.

  In the case of pigments, it is further advantageous in producing pigment inks to use an aqueous ink base dispersed in an aqueous medium. Specifically, FujiSP Black 8031, 8119, 8167, 8276, 8276, 8381, 8406, Fuji SP Red 5096, 5111, 5193, 5220, FujiSP Bordeaux 5500, Fuji SP Blue 6062, 6133, 6134, 6401, Fuji SP Green 7051, Fuji SPYellow 4060, 4178, Fuji SP Violet 9011, Fuji SP Pink 9524, 9527, Fuji SP Orange 534, FUJi SP Brown 35, FUJi SP Brown 35 Dye Co., Ltd.), Emacol Black CN, Emacol Blue FBB, FB, KR, EmacolGr en LXB, Emacol Violet BL, Emacol Brown 3101, Emacol Carmine FB, Emacol Red BS, Emacol Orange R, Emacol Yellow FD, IRN, 3601, GGN, F GN, G 10G, Sandy SuperBlack K, C, Sandy Super Gray B, Sandy Super Brown SB, FRL, RR, Sandy Super Green L 5G, GXB, Sandy H Super L FBL-160, FBB, Sandye Super Violet BL H / C, BL, Sandye Super B ordeaux FR, Sandy SuperPink FBL, F5B, Sandye SuperRubineFR, Sandy superRG G, RR, SandySuperRGF, R, BS, Sandy SuperG Ywllow GG, F3R, IRC, FGN, GN, GN, GRS, GSR-130, GSN-130, GSN, 10GN (from Sanyo Dye Co., Ltd.), RioFast BlackFx 8012, 8313 8169, Rio Fast Red Fx8209, 8172, Rio Fast Red S Fx 8315, 8316, RioFast Bl e Fx 8170, Rio Fast Blue FX 8170, Rio Fast Blue S Fx 8312, Rio Fast Green SFx 8314 (manufactured by Toyo Ink Co., Ltd.), NKW-2101, 2102, 2103, 2104, 2105, 2105, 2105, 2105, 2105 2107, 2108, 2117, 2127, 2137, 2167, 2101P, 2102P, 2103P, 2104P, 2105P, 2106P, 2107P, 2108P, 2117P, 2127P, 2137P, 2167P, NKW-3002, 3003, 3004, 3005, 3007, 3077, 3008, 3402, 3404, 3405, 3407, 3408, 3477, 3602, 36 03, 3604, 3605, 3607, 3677, 3608, 3702, 3703, 3704, 3705, 3777, 3708, 6013, 6038, 6559 (above, Nippon Fluorescence Corporation ), Cosmo Color S1000F series (manufactured by Toyo Soda Co., Ltd.), Victoria Yellow G-11, G-20, Victoria Orange G-16, G-21, Victoria Red G-19, G-22, Victoria Pink G-17, G-23, Victoria Green G-18, G-24, Victoria Blue G-15, G-25 (manufactured by Gokoku Color Co., Ltd.), Pollux PC5T1020, Pollux Black PC8T135, Pollux series such as Pollux Red IT1030 (Sumika Color Co., Ltd.) Is intended to be, they are those that can be used to select one or more.

  Water is used as the main solvent. In addition to water, various water-soluble organic solvents are used for the purpose of preventing ink drying and preventing freezing at low temperatures. Specifically, glycols such as ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, polyethylene glycol, 1,3-butylene glycol, thiodiethylene glycol, glycerin, ethylene glycol monomethyl ether, diethylene glycol monomethyl ether, 2-pyrrolidone, etc. These can be used alone or in combination of two or more.

  The shear thinning agent used in the present invention is added to make it possible to directly fill the ink into the hollow ink tank, etc., and by the force of rotation of the ball at the time of writing, compared with the time of setting. , A substance that imparts shear thinning to the ink to increase fluidity, for example, natural gum arabic, tragacanth, guar gum, locust bean gum, alginic acid, carrageenan, gelatin, casein, xanthan gum, dextran, semi-synthetic Methylcellulose, ethylcellulose, hydroxyethylcellulose, carboxymethylcellulose, starch glycolate, alginate, propylene glycol alginate, synthetic polyvinyl alcohol, polyvinylpyrrolidone, polyvinyl methyl ether, polyacrylate, Carboxymethyl polymer, polyethylene oxide, a copolymer of vinyl acetate and polyvinyl pyrrolidone, a water-soluble polymer compound such as polyacrylate. These can be used alone or in combination.

The polymer water-absorbing body used in the present invention is crosslinked so as to swell in a spherical shape, and forms a spherical swelled body in ink.
Specifically, SALCARE SC80 (alkyl acrylate / alkyl methacrylate copolymer, manufactured by Ciba Specialty Chemicals), SALCARE SC81 (acrylic acid methacrylate ether copolymer, Ciba Specialty Chemicals) SALCARE SC91 (sodium acrylate alkyl acrylate / sodium methacrylate / alkyl methacrylate copolymer, manufactured by Ciba Specialty Chemicals), SALCARE SC95 (choline methacrylate polymer, Ciba Specialty Chemicals) And SAALCARE SC96 (choline methacrylate polymer, manufactured by Ciba Specialty Chemicals Co., Ltd.). These can be used alone or in combination. These may be added to the ink as they are, or may be added after being dispersed and diluted with an ink solvent.

  Various resins can be used in combination as a binder in order to fix the colorant of the ink on the paper surface. Specifically, shellac, styrene-maleic acid copolymer, alkali metal salt of styrene-acrylic acid copolymer, amine salt, ammonium salt, alkali metal salt of α-methylstyrene-acrylic acid copolymer, A water-soluble resin such as the same amine salt or the same ammonium salt can be used.

  In addition to the above components, various additives conventionally used in water-based inks for writing instruments can be used as necessary. For example, sugar alcohols such as sorbit and xylit can be used to prevent ink evaporation, and lubricants such as alkali metal salts and amine salts of oleic acid can be used to improve writing feeling.

Furthermore, anionic, nonionic, cationic surfactants, silicone surfactants, fluorine surfactants and other surface tension modifiers, sodium dehydroacetate, 1,2-benzoisothiazin-3-one, etc. Anticorrosive agents such as benzotriazole and ethylenediaminetetraacetic acid, and alkali adjusters such as sodium hydroxide, alkanolamine, amine and ammonium can also be used as pH adjusters.

Hereinafter, the present invention will be described in detail with reference to examples. The viscosity of each ink in Examples and Comparative Examples was measured with a TV-20H viscometer manufactured by Tokimec Co., Ltd. at a shear rate of 3.83 / cm. The measurement temperature is 25 ° C.
The particle diameter of the polymer water-absorbing body in the ink was measured by thinly spreading the ink on a glass plate and using a digital microscope VH-8000 manufactured by Keyence Corporation.
In each comparative example, “part” means “part by weight”.

Example 1
SP BLACK 8922 (black aqueous pigment base, manufactured by Fuji Color Co., Ltd.)
25.00 parts Water 54.35 parts Glycerin (solvent) 20.00 parts Kelzan (xanthan gum, shear thinning agent, manufactured by Sanki Co., Ltd.) 0.30 parts SALCARE SC91 (polymer water absorbent, Ciba Specialty Chemicals Co., Ltd.)
0.30 parts 1,2-benzisothiazin-3-one (preservative) 0.05 parts Kelzan is continuously added little by little so that water and glycerin are mixed and stirred. Stir for 5 minutes with a homogenizer to dissolve the Kelzan. Next, SP BLACK 8922 is added and stirred for 5 minutes with a homogenizer. Next, SALCARE SC90 is added and stirred with a homogenizer for 5 minutes. Add 1,2-benzisothiazalin-3-one and stir with a homogenizer for 2 minutes.
Next, defoaming was performed by centrifugal force to obtain a black pigment aqueous ink having a viscosity of 1500 mPa. The polymer water-absorbing body in the ink was spherical and the particle diameter was 1 μm or more and less than 15 μm.

Example 2
Pollux Red PM-R (Red aqueous pigment base, manufactured by Sumika Color Co., Ltd.)
25.00 parts Water 44.35 parts Glycerin (solvent) 20.00 parts Propylene glycol (solvent) 10.00 parts CMC Daicel 2260 (Carboxymethylcellulose, shear thinning agent, Daicel Chemical Industries, Ltd.) 0.60 SALCARE SC95 (polymer water absorbent, manufactured by Ciba Specialty Chemicals Co., Ltd.)
0.05 parts Water, glycerin, and propylene glycol are mixed and stirred, and CMC Daicel 2260 is continuously added little by little so as not to become lumps. CMC Daicel 2260 is dissolved by stirring for 60 minutes with a propeller stirrer. Next, Pollux Red PM-R is added and stirred for 30 minutes with a propeller stirrer. Next, SALCARE SC91 is added and stirred with a homogenizer for 2 minutes.
Next, defoaming was performed by centrifugal force to obtain a red pigment aqueous ink having a viscosity of 2500 mPa. The polymer water-absorbing body in the ink was spherical and the particle diameter was 1 μm or more and less than 15 μm.

Example 3
NKW2117 (Pink aqueous pigment base, manufactured by Nippon Fluorochemicals Co., Ltd.) 50.00 parts Water 30.85 parts Glycerin (solvent) 15.00 parts Carbopol 980 (Carboxyvinyl polymer, shear thinning agent, USA) 0.15 parts SALCARE SC96 (polymer water absorbent, manufactured by Ciba Specialty Chemicals Co., Ltd.)
3.00 parts Demol N (surfactant, manufactured by Kao Corporation) 1.00 parts Water, glycerin, and Demol N are mixed and stirred with a propeller stirrer for 30 minutes. Next, while stirring, Carbopol 980 is continuously added little by little so as not to become lumpy. Stir for 60 minutes with a propeller stirrer to dissolve Carbopol 980. Next, add NKW2117 and stir for 60 minutes with a propeller stirrer. Next, SALCARE SC80 is added and stirred with a homogenizer for 2 minutes.
Next, defoaming was performed by centrifugal force to obtain a pink pigment aqueous ink having a viscosity of 1700 mPa. The polymer water-absorbing body in the ink was spherical and the particle diameter was 1 μm or more and less than 15 μm.

Example 4
Water black 250L (black dye base, manufactured by Orient Chemical Co., Ltd.)
20.00 parts water 64.35 parts ethylene glycol (solvent) 15.00 parts Kelzan (xanthan gum, shear thinning agent, manufactured by Sanki Co., Ltd.) 0.30 parts SALCARE SC80 (polymer water absorbent, Ciba Specialty)・ Chemicals Co., Ltd.)
0.30 parts 1,2-Benzisothiazin-3-one (preservative) 0.05 parts Add water and ethylene glycol continuously while adding water and ethylene glycol little by little so as not to become lumps. . Stir for 5 minutes with a homogenizer to dissolve the Kelzan. Next, 250 L of water black is added and stirred for 2 minutes with a homogenizer. Next, SALCARE SC90 is added and stirred with a homogenizer for 5 minutes. Add 1,2-benzisothiazalin-3-one and stir with a homogenizer for 2 minutes.
Next, defoaming was performed by centrifugal force to obtain a black dye aqueous ink having a viscosity of 1400 mPa. The polymer water-absorbing body in the ink was spherical and the particle diameter was 1 μm or more and less than 15 μm.

Comparative Example 1
A black aqueous pigment ink having a viscosity of 1300 mPa was obtained in the same manner as in Example 1 except that SALCARE SC91 of Example 1 was added and water was added in that amount.

Comparative Example 2
Except for SALCARE SC91 of Example 1, the same amount as that of Rheology 250H (sodium polyacrylate, polymer water absorbent, manufactured by Nippon Pure Chemical Co., Ltd.) was added, and the viscosity was 1500 mPa. A black aqueous pigment ink was obtained. The particle diameter of the polymer water-absorbing body in the ink was 1 μm or more and less than 15 μm, and was not spherical but irregular.

Comparative Example 3
Fuji SP Blue 6401 (blue pigment base, manufactured by Fuji Dye Co., Ltd.)
26.00 parts Kelzan AR (xanthan gum, shear thinning resin, manufactured by Sanki Co., Ltd.) 0.05 parts Rhegic GX205 (crosslinked poly-N-vinylacetamide, polymer water absorbent, Nippon Pure Chemical Co., Ltd.)
Manufactured) 10.0 parts ethylene glycol 10.0 parts glycerin 10.0 parts water 43.05 parts benzotriazole (rust inhibitor) 0.5 parts Proxel GXL (preservative, manufactured by Zeneca) 0.30 parts amino Methylpropanediol (pH adjuster) 0.10 parts In the above ingredients, Rheological GX205 and water were stirred with a high shear force for 30 minutes with a homogenizer, then added with Kelzan AR and stirred for 30 minutes with a lab mixer. A Kelzan aqueous solution containing rheological GX205 dissolved and swollen was prepared. The remaining components were added thereto, and further mixed and stirred for 2 hours to obtain a blue ink. The particle diameter of the polymer water-absorbing body in the ink was 1 μm or more and less than 15 μm, and was not spherical but irregular.

Comparative Example 4
Except for SALCARE SC91 of Example 1, KPM957 (silicon rubber fine particles, particle size of 1 μm or more and less than 15 μm, manufactured by Shin-Etsu Chemical Co., Ltd.) was added in the same amount as in Example 2 to obtain a black aqueous solution having a viscosity of 1500 mPa. A pigment ink was obtained. Since KMP957 is non-water-absorbing, the particle diameter was 1 μm or more and less than 15 μm even in the ink.

Comparative Example 5
Except for SALCARE SC91 of Example 1, KPM957 (silicon rubber fine particles, particle size of 1 μm or more and less than 15 μm, manufactured by Shin-Etsu Chemical Co., Ltd.) was changed to 20.00 parts, and water was changed to 34.65 parts. As a result, a black aqueous pigment ink having a viscosity of 1500 mPa was obtained. Since KMP957 is non-water-absorbing, the particle diameter was 1 μm or more and less than 15 μm even in the ink.

Comparative Example 6
Except for the SALCARE SC91 of Example 1, Rheological 250H (sodium polyacrylate, polymer water absorbent, manufactured by Nippon Pure Chemical Co., Ltd.) was added in that amount. While mixing and stirring water and glycerin, Kelzan is continuously added little by little so as not to become lumps. Stir for 5 minutes with a homogenizer to dissolve the Kelzan. Next, SP BLACK 8922 is added and stirred for 5 minutes with a homogenizer. Next, Rheological 250H90 is added and stirred for 30 minutes with a propeller stirrer. 1,2-Benzisothiazarin-3-one is added and further stirred with a propeller stirrer for 30 minutes. Next, defoaming was performed by centrifugal force to obtain a black pigment aqueous ink having a viscosity of 1700 mPa. The polymer water-absorbing body in the ink was spherical and the particle size was 30 μm or more and less than 250 μm.

  As described above, the water-based inks obtained in Examples 1 to 4 and Comparative Examples 1 to 6 were made of polypropylene hollow with a stainless steel ballpoint pen tip (carbide ball, φ0.5 mm) for K105 manufactured by Pentel Co., Ltd. connected to one end. A transparent ink containing tube made of a cylinder was filled with 0.8 g. An ink follower in which an α-olefin oligomer was gelled with fine-particle silica and a dextrin fatty acid ester was injected into the rear end interface portion of the ink to obtain a test ballpoint pen.

  Using this test ballpoint pen, five inks were tested for each ink of each Example and Comparative Example for ink leakage, ink leakage under humid conditions, confirmation of writing lines, and confirmation of writing lines. The results are shown in Table 1. In addition, the measured value described the average value of five.

Ink leakage: The length of the ink ball that leaked from the pen tip and accumulated at the tip when left for 2 hours at room temperature with the pen tip facing downward was measured.

Ink leakage under humid conditions: Put water in a desiccator, make it saturated with water vapor (humidity 100%), leave the pen tip downward in it for 2 hours and leak from the pen tip to the tip The length of the accumulated ink ball in the direction of gravity was measured.

Confirmation of the writing line: When using a drawing machine (Pentel Co., Ltd., model TO51), when the writing angle is 70 °, the writing load is 100 g, and the writing speed is 7 cm / sec. The total length was measured using the unspotted portion as a scrap.

Confirmation of stenographic writing line: When using a drawing machine (Pentel Co., Ltd., model TO51), when the writing angle is 70 °, the writing load is 100 g and the writing speed is 14 cm / sec, the ink is printed on the paper surface The part where it was not attached was scraped, and the total length was measured.

Claims (1)

A water-based ink for ballpoint pens comprising at least a colorant, water, a shear thinning agent, and a spherically swollen polymer water-absorbing body, and the polymer water-absorbing agent is added after the shear thinning agent is dissolved in water. Manufacturing method.