JP3788068B2 - Water-based ink for ballpoint pens - Google Patents

Description

上記各成分を２時間混合、撹拌し粘度４ｃｐｓの黒色水性インキを得た。
【００２１】

上記各成分中水を攪拌しながらケルザンＳを徐々に加え、１時間混合撹拌を行いケルザン水溶液をえた。これに残りの成分を加え２時間攪拌して粘度３００ｃｐの黄色水性インキを得た。
【００２２】

上記各成分中水とポリヒドロキシプロピル化グァーガムを１時間混合撹拌した。次いで残りの成分を加え、２時間攪拌して粘度１１００ｃｐの桃色水性インキを得た。
【００２３】

上記各成分中水に水酸化ナトリウムとサルコシネートＯＨを加え攪拌し、均一に溶解した後、残りの成分を加え２時間攪拌して粘度３ｃｐの黒色水性インキを得た。
【００２４】
比較例１
実施例１の２，５−ジメルカプト−１，３，４−チアジアゾールの２量体の代わりに水を加えた以外は同様に為して粘度４ｃｐの黒色の水性インキを得た。
【００２５】
比較例２
実施例２において２，５−ジメルカプト−１，３，４−チアジアゾールの５量体の代わりに水を加えた以外は同様に為して粘度２９０ｃｐの黄色水性インキを得た。
【００２６】
比較例３
実施例３において、２，５−ジメルカプト−１，３，４−チアジアゾールの７量体の代わりオレイン酸トリエタノールアミンを０．５部、水を１．１部加えた以外は同様に為して粘度１１３０ｃｐの桃色水性インキを得た。
【００２７】
比較例４
実施例４において２，５−ジメルカプト−１，３，４−チアジアゾールの３量体の代わりにニッコールＴＤＰ−１０（トリＰＯＥ（１０）アルキルエーテルリン酸、日光ケミカルズ（株）製）を加えた以外は同様に為して粘度３ｃｐｓの黒色水性インキを得た。
【００２８】
【効果】
以上で得られた実施例、比較例のインキを実施例１と４，比較例１と４は樹脂製のチップに超硬ボールを抱持したインキ吸蔵体式の水性ボールペン、ボールＰｅｎｔｅｌ Ｂ１００（ぺんてる（株）製 ）の部品に充填して試験用サンプルとした。
実施例２と３，、比較例２と３は超硬ボールを抱持したステンレス製ボールペンチップを一端に接続したポリプロピレン製の中空筒体よりなる透明なインキ収容管に充填して試験用サンプルとした。滲みと書き味について試験した結果を表１に示す。
【００２９】
【表１】

【００３０】
▲１▼滲み試験：筆記用紙Ａ（ＪＩＳ Ｐ３２０１）に２０ｃｍの直線を筆記して、１０〜１１ｃｍの間の筆跡を実体顕微鏡で観察し滲みの無い部分の筆跡幅を５ヶ所測定する。次いで同じ範囲の滲み（紙繊維に沿ってインキが移動した部分）の長さを５ヶ所測定した平均値が筆跡幅の平均値の何％に当たるか計算した。
【００３１】
▲２▼初期書き味試験：筆記用紙Ａ（ＪＩＳ Ｐ３２０１）に手書きにて直径２ｃｍの丸を１０個連続筆記したときの書き味の軽さを官能で評価した。
【００３２】
▲３▼経時書き味試験：５０℃に２ヶ月経時した各ボールペンサンプルを用い、筆記用紙Ａ（ＪＩＳ Ｐ３２０１）に手書きにて直径２ｃｍの丸を１０個連続筆記したときの書き味の軽さを官能で評価した。
【００３３】
以上詳細に説明したように、本発明に係る水性ボールペン用インキは滲みが少なく滑らかな軽い書き味を経時後も維持する優れたものである。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a water-based ink for ballpoint pens that can be used regardless of the ink occlusion type or the direct liquid type, and further relates to a water-based ink for ballpoint pens that has a smooth and light writing texture even after a long period of time.
[0002]
[Prior art]
Conventionally, various attempts have been made to obtain a smooth and light writing taste in a ballpoint pen using water-based ink, and as a lubricant, for example, a phosphate ester surfactant, a water-soluble cutting oil, a higher unsaturated fatty acid and It is known to add lubricants such as / or salts thereof.
[0003]
[Problems to be solved by the invention]
However, when these lubricants are used in water-based inks, the surface tension of the ink is lowered, the paper fibers and the ink become wet, and the ink is easily moved, so that the handwriting blurs.
Further, the above-described conventional lubricant has a problem that, when the ball-point pen filled with the ink is kept for a long time, the ball surface is rough and the initial smooth light writing cannot be maintained because of no corrosion prevention effect. An object of this invention is to provide the water-based ink for ball-point pens which has a smooth light writing taste in the initial stage and long-term aging, without making it easy to spread.
[0004]
[Means for Solving the Problems]
That is, the gist of the present invention is a water-based ink for ballpoint pens comprising at least a colorant, water, and an oligomer of 2,5-dimercapto-1,3,4-thiadiazole.
[0005]
Hereinafter, each component of the present invention will be described in detail.
Water is used as the main solvent.
As the colorant, either a dye or a pigment can be used.
As the dye, conventional acid dyes and direct dyes can be preferably used. Specifically, Japanol Fast Black D Conch (CI Direct Black 17), Water Black 100L (19), Water Black L-200 (19), Water Black # 7 (19), Kaya Set Black W9 (19), Direct Fast Black B (22), Direct Fast Black AB (32), Direct Deep Black EX (38), Direct Deep Black (similar to the same 38), Direct Fast Black Conch (same 51), Kayara Spragley VGN (71), Kayak Direct Brilliant Yellow G (CI Direct Yellow 4) Direct Fast Yellow 5GL (26) ), Eisen Buri Murae -GCLH (44), Direct Fast Yellow R (50), Eisen Direct Fast Red FH (CI Direct Red 1), Nippon Fast Scarlet GSX (Same 4), Direct Fast Scarlet 4BS (Same 23), Eisen Direct Durin BH (31), Direct Scarlet B (37), Kayak Direct Scarlet 3B (39), Aizen Murmura Bink 2BLH (75), Sumilite Red F3B (80), Aisen Brim Red 4BH (Same as 81) Kayalas Spralbin BL (same as 83), Kayalas Light Red F5G (same as 225), Kayalas Light Red F5B (same as 226), Kayalas Light Rose FR (same as 227) Direct Sky Blue 6B (C.I. I. Direct Blue ), Direct Sky Blue 5B (same as 15), Benzo Brilliant Sky Blue 8GS (same as 41), Sumilite Splash Blue BRR Conch (same as 71), Dibogen Turquoise Blue S (same as 86), Water Blue # 3 (same as 86) , Kayara Star Coyze Blue GL (86), Daiwa Blue 215H (87), Kayala Supra Blue FF2GL (106), Kayara Supra Blue FFRL (108) Kayara Splatter Blue FBL (199) Direct dyes, Acid Blue Black 10B (CI Acid Black 1), Nigrosine (2), Water Black R455 (2), Water Black R510 (2), Suminol Milling Black 8BX (24), Kayanol Milling Black VLG (2) 6), Kyanol Milling 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 (same as above) 107), Kayanol Milling Black TLB (109), Suminol Milling Black B (109), Kayanol Milling Black TLR (110), Eisen Opal Black New Conch (119), Water Black 187-L (same as above) 154) Acid Yellow # 10 (C.I. I. Acid Yellow 1), Kayak Acid Brilliant Flavin FF (7: 1), Kayasil Yellow GG (17), Xylene Light Yellow 2G 140% (17), Suminol Leveling Yellow NR (19), Water Yellow # 1 (same as above) 23), Daiwa Torazine (same 25), Kyakuto Tolazine (same 23), Suminol Fast Yellow R (same 25) Diacid Light Yellow 2GP (same 29), Suminol Milling Yellow O (same 38), Sumi Noor Milling Yellow MR (42), Water Yellow # 6 (42), Kayanol Yellow NFG (49), Suminol Milling Yellow 3G (72), Suminol Fast Yellow G (61), Sumi Nord Milling Yellow G (78), Kayano Yellow N5G (110), Sumino Milling Yellow 4G 200% (same as 141), Kayanol Yellow NG (same as 135), Cayanol Milling Yellow 5GW (same as 127), Kayano Milling Yellow 6GW (same as 142), Sumitomo Fast Scarlet A (CI Acid Red) 8), Kayak Silk Scarlet (same 9), Solar Rubin Extra (same 14), Daiwa New Coxin (same 18), Water Scarlet (same 18), Daiwa Red 102 (same 18), Eisenbonso RH (same as above) 26), Daiwa Red No. 2 (same as 27), Suminol Leveling Brilliant Red S3B (same as 35), Kayasil Rubinol 3GS (same as 37), Eisen Erythrosine (same as 51), Kayaqua acid Rhodamine FB (same as 52), Daiwa Red No. 106 (52), Suminol Leveling Ruby 3GP (57), diacy alizarin rubinol F3G 200% (82), alizarin rubinol 5G (83), Eiseneosin GH (87), Water Red # 2 (87), Daiwa Red 103WB ( 87), Water Pink # 2 (92), Eisen Acid Phloxin PB (92), Daiwa Red No. 104 (92), Rose Bengal (94), Kayanol Milling Scarlet FGW (111), Kayanol Milling Lubin 3BW (129), Suminol Milling Brilliant Red 3BN Conch (131), Suminol Milling Brilliant Red BS (138), Eisen Opal Pink BH (186), Suminol Brilliant Red B Conch (249) , Kayak acid brilian Tread 3BL (same as 254), kayak acid brilliant red BL (same as 265), Kayanor Milling Red GW (same as 276), Mitsui Acid Violet 6BN (C.I. I. Acid Violet 15), Mitsui Acid Violet BN (17), Water Violet # 1 (49), Water Violet # 5 (49), Daiwa Purple 1 (49), Ink Violet L10 (49), Sumitomo Patent Pure Blue VX (CI Acid Blue 1), Water Blue # 106 (1), Patent Blue AF (7), Water Blue # 9 (9), Daiwa Blue No. 1 (9), Ink Blue L20 (same 9), Supranol Blue B (same 15), Water Blue # 116 (same 15), Orient Soluble Blue OBC (same 22), Orient Soluble Bull-OBX (same 22), Small leveling Blue 4GL (23), Mitsui Nylon Fast Blue G (25), Kayasil Blue A G (40), Kayasil Blue BR (41), Mitsui Alizarin Saphirol SE (43), Suminol Leveling Sky Blue R Extraconk (62), Mitsui Nylon Fast Sky Blue R (78), Sumitomo Brilliant India Cyanine 6Bh / e (83), Sandlancyanine N-6B 350% (90), Water Blue # 115 (90), Water Blue # 105 (90), Orient Soluble Blue OBB (93), Spula Norcyanin 7BF (same as 100), Sumitomo Brilliant Blue 5G (same as 103), Acid Blue (same as 103), Asilane Brilliant Blue FFR (same as 104), Kyanol Milling Ultra Sky SE (same as 112), Kyanol Milling Cyanine 5R (113) Eisen Opal Cyanine 2GLH (158), Daiwa Guinea Green B (CI Acid Green 3) Acid Brilliant Milling Green (9), Daiwa Green # 70 (16), Kayanol Cyanine Green G (25) ), Suminol Milling Green G (27), Water Orange # 17 (CI Acid Orange 56), Water Yellow # 2 (CI Food Ero-3), Food Yellow No. 5 (CI Food Yellow 3) Food Red 3 (CI Food Red 14), Food Blue 2 (CI Acid Blue 74), Food Green 2 (CI Acid) Food dyes such as Green 5), Malachite Green (C.I. 42000), Victoria Blue FB (C.I. 44045), Methyl Bio Let FN (C.I. I. 42535), rhodamine F4G (C.I. 45160), rhodamine 6GCP (C.I. 45160) and the like.
[0006]
As the pigment, conventionally known pigments can be used. Specific examples include Special Black 6, S170, S610, 5, 4, 4A, 550, 35, 250, 100, Printex 150T, U, V, 140U, 140V, 95, 90, 85, 80, 75, 55, 45, P, XE2, L6, L, 300, 30 , 3, 35, 25, 200, A, G (Degussa Japan Co., Ltd.), # 2400B, # 2350, # 2300, # 2200B, # 1000, # 950, # 900 # 850, # MCF88, MA600, MA100, MA7, MA11, # 50, # 52, # 45, # 44, # 40, # 33, # 32, # 30, CF9, # 20B, # 4000B (Mitsubishi Conversion Industrial Co., Ltd.), MONARCH 1300, 1100, 1000, 900, 880, 800, 700, MOGUL L, REGAL 400R, 660R, 500R, 330R, 300R, 99R, ELFEX 8, same 12, BLACK PEARLS 2000 (above, manufactured by Cabot Co. LTD, USA), Raven 7000, 5750, 5250, 5000, 3500, 2000, 1500, 1255, 1250, 1200, same 1170, 1060, 1040, 1035, 1020, 1000, 890H, 890, 850, 790, 780, 760, 500, 450, 430, 420, 410, 22, 22, 16, 825 Oil Beads, H2 , C, Conductex 975, 900, SC (Columbian Carbon Japan Co., Ltd.), etc., carbon black, KA-10, 10P, 15, 20, 30, 30, 35, 60 80, 90, KR-310, 380, 460, 480 (above, manufactured by Titanium Industry Co., Ltd.), P25 (manufactured by Nippon Aerosil Co., Ltd.), BS-605, 607 (Above, manufactured by Toyo Aluminum Co., Ltd.), bronze powder P-555, P-777 (above, manufactured by Nakajima Metal Foil Industry Co., Ltd.), bronze powder 3L5, 3L7 (above, Fukuda Metal Foil Industry Co., Ltd.) Metal powder pigments such as black iron oxide, yellow iron oxide, red iron oxide, inorganic pigments such as ultramarine, bitumen, cobalt blue, chrome green, chrome oxide, Hansa A-10G, 5G 3G, 4 and GR, A, Benzine Yellow, Permanent Yellow NCG, Tartrazine Lake, Quinoline Yellow, Sudan 1, Permanent Orange, Indanthrene Brilliant Orange GN, Permanent Brown FG, Para Brown, Permanent Red 4R, Fire Red, Brilliant Carmine BS, Pyrazolone Red, Lake Red C, Quinacridone Red, Brilliant Carmine 6B, Bordeaux 5B, Thioindigo Red, Fast Violet B, Dioxane Violet, Alkaline Blue Lake, Phthalocyanine Blue, Indigo, Acid Green Lake And organic pigments such as phthalocyanine green. In addition, inorganic fluorescent pigments such as zinc sulfide, zinc silicate, cadmium zinc sulfate, calcium sulfide, strontium sulfide, and calcium tungstate, and other known organic fluorescent pigments can be used. The above-mentioned colorants can be used alone or in combination with others, and the amount of use varies depending on the color tone, etc., but if the amount is small, the coloring of the handwriting is poor, and if the amount is large, the colorant is insufficiently dissolved / dispersed. In this case, a problem such as precipitation, sedimentation, and clogging at the pen tip occurs.
[0007]
Here, when a pigment is used as the colorant, it is preferable to use a dispersant in combination. However, as the dispersant, conventionally used water-soluble or water-soluble resins, anionic or nonionic surfactants, etc. What is used as a dispersant for the pigment of the above can be used. For example, as a polymer dispersant, natural rubbers such as gum arabic and tragacanth, glucosides such as saponin, cellulose derivatives such as methylcellulose, carboxycellulose, and hydroxymethylcellulose, natural high substances such as lignin sulfonate, shellac, etc. Molecules, polyacrylates, salts of styrene-acrylic acid copolymers, salts of vinylnaphthalene-maleic acid copolymers, sodium salts of β-naphthalenesulfonic acid formalin condensates, phosphates, etc. Examples thereof include nonionic polymers such as molecules, 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- Anionic surfactants such as olefin sulfonate, alkyl phosphate, polyoxyethylene alkyl ether phosphate, polyoxyethylene alkyl phenol ether, polyoxyethylene alkyl ether, sorbitan alkyl ester, polyoxyethylene sorbitan alkyl ester Nonionic surfactants such as These 1 type (s) or 2 or more types can be selected and used. If the amount of the dispersant used is too small, the desired dispersion effect cannot be obtained, and if too large, no further improvement in the dispersion effect is observed, which is uneconomical. For this reason, it is preferable to use 0.2-20 weight part of dispersing agents with respect to 10 weight part of pigments to be used.
[0008]
Furthermore, in the case of pigment inks, it is advantageous in producing pigment inks to use an aqueous ink base in which pigments are dispersed in an aqueous medium. Specifically, Fuji SP Black 8031, 8119, 8167, 8167, 8276, 8381, 8406, Fuji SP Red 5096, 5111, 5193, 5220, Fuji SP Bordeaux 5500, Fuji SP Blue 6062, 6133, 6134, Fuji SP Green 7051, Fuji SP Yellow 4060, Fuji SP Violet 9011, Fuji SP Pink 9524, 9527, Fuji SP Orange 534, FUji SP Brown 3074 CN, Emacol Blue FBB, FB, KR, Emacol Green LXB, Emacol Violet BL, Emacol Br wn 3101, Emacol Carmine FB, Emacol Red BS, Emacol Orange R, Emacol Yellow FD, IRN, 3601, FGN, GN, GG, F5G, F7G, 10GN, 10G, Sandy B ck Same C, Sandy Super Gray B, Sandy Super Brown SB, FRL, Same RR, Sandy Super Green L5G, Same GXB, Sandy Super Navy Blue HRL, 160 GBL, H, GLL, H FBB, Sandy Super Violet BL H / C, BL, Sandy Super Bordeaux FR, Sandy Super Pink FBL Same F5B, Sandy SuperRubine FR, Sandy super Carminine FB, Sandy Super Red FFG, RR, BS, Sandy Super Orange FL, R, BO, Sandy Gold G F3R, IRC, same FGN, same GN, same GN, same GRS, same GSR-130, same GSN-130, same GSN, 10 GN (manufactured by Sanyo Dye Co., Ltd.), Rio FastBlack Fx 8012, 8313, 8169 , Rio Fast Red FX 8209, 8172, Rio Fast Red S Fx 8315, 8316, Rio Fast Blue FX 8170, RioFast Blue FX 8170 , Rio Fast Blue S Fx 8312, Rio Fast Green S Fx 8314 (manufactured by Toyo Ink Co., Ltd.), NKW-2101, 2102, 2103, 2104, 2105, 2106, 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, 3603, 3604, 3605, 3607, 3777, 3608, 3702, 3703, 3704, 3705, 3777, 3708, 6013, 6038, 6559 (manufactured by Nippon Fluorescence Co., Ltd.), Cosmo Color S 1000F Series (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.) and the like can be mentioned, and these can be used by selecting one or more. .
[0009]
The oligomer of 2,5-dimercapto-1,3,4-thiadiazole is used to make the writing quality of a ballpoint pen smooth and light. Among these oligomers, a dimer to a 10-mer are preferable. If the molecular weight is larger than that of the 10-mer, it is difficult to dissolve in the ink, and the insoluble matter may clog in the ink passage at the tip of the ballpoint pen over time. Monomers have little effect of imparting a smooth writing feel. The amount used is preferably 0.01 to 5 parts by weight based on the total amount of ink. If it is less than 0.01 parts by weight, the effect of making a smooth and light writing texture is reduced. Further, even if it is added in an amount of more than 5% by weight, it is difficult to dissolve in the ink, so that the insoluble oligomer of 2,5-dimercapto-1,3,4-thiadiazole may cause clogging in a narrow ink passage at the tip of the ballpoint pen.
[0010]
In addition to the above essential components, various water-soluble organic solvents can be used in the present invention. The water-soluble organic solvent is used for various purposes as a water-based ink for ballpoint pens, for example, for preventing ink drying at the pen tip, preventing ink freezing at low temperatures, and a pigment dispersion medium. Specifically, alcohols such as methanol, ethanol, 1-propanol, 2-propanol, isobutyl alcohol, 1-hexanol, benzyl alcohol, ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1, Glycols such as 3-butanediol, hexylene glycol, glycerin, diethylene glycol, triethylene glycol, 1,3 butylene glycol, dipropylene glycol, polypropylene glycol, thiodiglycol, 1,2-diethoxysilane, 1,2-dibutoxy Ethers such as ethane, diethylene glycol diethyl ether, diethylene glycol dibutyl ether, nitrogen compounds such as acetonitrile, N-methyl-2-pyrrolidone, 2-pyrrolidone, formamide, 2- Toxiethanol, 2-ethoxyethanol, 2- (methoxymethoxy) ethanol, 2-isopropoxyethanol, 2-butoxyethanol, 2-isopentyloxyethanol, 2-hexyloxyethanol, 2-phenoxyethanol, 2-benzyloxyethanol , Furfuryl alcohol, tetrahydrofurfuryl alcohol, 2- (2-methoxyethoxy) ethanol, 2- (2-ethoxyethoxy) ethanol, 2- (2-butoxyethoxy) ethanol, 1-methoxy-2-propanol, 1 Etoxy-2-propanol, monoethanolamine, diethanolamine, triethanolamine, 2-methoxyethyl acetate, 2-ethoxyethyl acetate, 2-butoxyethyl acetate, 2-phenoxyethyl Acetate, etc. can be used.
These can be used alone or in combination of two or more. In addition, when the amount used is small, insoluble / aggregates are generated due to insufficient dissolution or dispersion of each composition in the ink, and when it is large, the concentration of each composition in the ink is reduced and the effect is reduced. Since various problems occur, 5 to 40% by weight is preferable with respect to the total amount of ink.
[0011]
Furthermore, for the purpose of adjusting the viscosity of the ink composition, cross-linked and non-cross-linked poly-N-vinyl carboxylic acid amide, polyvinyl alcohol, polyvinyl methyl ether, polyethylene oxide, vinyl acetate and polyvinyl pyrrolidone copolymer, polyacrylic acid , Carboxyvinyl polymers, resins such as copolymers of acrylic acid and alkyl methacrylate and / or their salts, natural gum arabic, tragacanth gum, xanthan gum, guar gum, locust bean gum, alginic acid, carrageenan, gelatin, casein, dextran, half Synthetic methylcellulose, ethylcellulose, hydroxyethylcellulose, carboxymethylcellulose, sodium starch glycolate, sodium alginate, propylene glycol alginate Such derivatives of the foregoing and the like.
[0012]
Further, in order to suppress ink outflow inhibition in the ink passage of the ink writing tool due to generation of wrinkles, sodium dehydroacetate, 1,2-benzisothiazolin-3-one, 5-chloro-2-methyl-4-isothiazoline-3 -An appropriate amount of antiseptic / antifungal agent such as 2,4-thiazolylbenzimidazole, methyl-2-benzimidazole, carbamate, sorbic acid, potassium sorbate, benzoic acid, sodium benzoate, paraoxybenzoate It can also be added.
[0013]
Furthermore, in the case of a writing instrument using a metal in a portion that comes into contact with the ink, a rust preventive such as benzotriazole or ethylenediaminetetraacetic acid can be added to prevent the metal from being corroded.
In order to adjust the pH of the ink, various alkalizing agents such as sodium hydroxide, potassium hydroxide, sodium carbonate, sodium hydrogen carbonate, ammonia, organic amines, alkanolamines, hydroxyalkylaminoethanol, perfumes, Additives such as foaming agents can be used as necessary.
[0014]
In producing the water-based ink for ballpoint pens of the present invention, various conventionally known methods can be employed. For example, when a dye or a dispersed pigment is used as a colorant, the mixture is stirred and mixed by a stirrer such as a turbo mixer. When a pigment that is not dispersed as a colorant is used, a ball mill, a sand grinder, or a speed line is used. It can be easily obtained by mixing and grinding with a disperser such as a mill or a roll mill. At this time, the dispersed pigment may be used again on the disperser.
[0015]
[Action]
In the present invention, when a water-based ink added with an oligomer of 2,5-dimercapto-1,3,4-thiadiazole is used in a ballpoint pen, it is presumed that a smooth light writing taste can be obtained even with a long period of time. Disulfide bond part of dimercapto-1,3,4-thiadiazole oligomer and sulfur atom in thiadiazole ring coordinate with metal and / or metal compound on the surface of ball as writing member and chip holding this ball Join. As a result, the surface of the chip or ball is covered with an oligomer of 2,5-dimercapto-1,3,4-thiadiazole, and an organic film is formed on the surface, and this film is in friction with the chip during the rotation of the ball. It seems that smooth light writing taste can be obtained by reducing the force.
[0016]
Here, since the oligomer of 2,5-dimercapto-1,3,4-thiadiazole is a 2 to 10-mer, it can be coordinated with a metal or a metal compound in a large number, and is more firmly formed than a monomer. It seems to be bound to the surface and the effect of smooth light writing lasts for a long time.
[0017]
Further, since this film does not have electrical conductivity, it prevents the battery reaction from occurring over time on the ball or chip surface. This seems to prevent the writing quality from being deteriorated due to the corrosion of the balls and chips over a long period of time and maintain the initial smooth and light writing quality.
[0018]
Further, since the oligomer of 2,5-dimercapto-1,3,4-thiadiazole has almost no surface activity effect, it hardly affects the surface tension of the ink even if it is added to the ink. The ease of movement does not change, so it does not easily spread.
[0019]
【Example】
Hereinafter, the present invention will be described in detail with reference to examples. The viscosity of each ink in the Examples and Comparative Examples is measured with a standard cone rotor 10 rpm manufactured by Tokimec Co., Ltd., less than 50 cps, and the standard viscosity of ELD viscometer manufactured by Tokimec Co., Ltd. is 50 cps or more and less than 600 cps. Measured at 1 rpm, 600 cps or more and less than 2000 cps, measured by Tokimec ELD viscometer ST rotor 10 rpm, 2000 cps or more measured by Tokimec ELD viscometer ST rotor Measurement was performed at 2.5 rpm. The temperature at the time of measurement was 25 ° C. In each example, “part” simply means “part by weight”.
[0020]

The above components were mixed and stirred for 2 hours to obtain a black aqueous ink having a viscosity of 4 cps.
[0021]

While stirring the water in each of the above components, Kelzan S was gradually added and mixed and stirred for 1 hour to obtain a Kelzan aqueous solution. The remaining components were added thereto and stirred for 2 hours to obtain a yellow aqueous ink having a viscosity of 300 cp.
[0022]

Water in each of the above components and polyhydroxypropylated guar gum were mixed and stirred for 1 hour. Next, the remaining components were added and stirred for 2 hours to obtain a pink aqueous ink having a viscosity of 1100 cp.
[0023]

Sodium hydroxide and sarcosinate OH were added to the water in each of the above components and stirred to dissolve uniformly. Then, the remaining components were added and stirred for 2 hours to obtain a black aqueous ink having a viscosity of 3 cp.
[0024]
Comparative Example 1
A black aqueous ink having a viscosity of 4 cp was obtained in the same manner except that water was added instead of the dimer of 2,5-dimercapto-1,3,4-thiadiazole of Example 1.
[0025]
Comparative Example 2
A yellow aqueous ink having a viscosity of 290 cp was obtained in the same manner as in Example 2 except that water was added instead of the pentamer of 2,5-dimercapto-1,3,4-thiadiazole.
[0026]
Comparative Example 3
In Example 3, the same procedure was followed except that 0.5 parts of triethanolamine oleate and 1.1 parts of water were added instead of the pentamer of 2,5-dimercapto-1,3,4-thiadiazole. A pink aqueous ink having a viscosity of 1130 cp was obtained.
[0027]
Comparative Example 4
In Example 4, instead of 2,5-dimercapto-1,3,4-thiadiazole trimer, Nikkor TDP-10 (tri-POE (10) alkyl ether phosphate, manufactured by Nikko Chemicals Co., Ltd.) was added. In the same manner, a black aqueous ink having a viscosity of 3 cps was obtained.
[0028]
【effect】
The inks of Examples 1 and 4 and Comparative Examples 1 and 4 of the Examples and Comparative Examples obtained above were ink-absorbing water-based ballpoint pens, Ball Pentel B100 (Pentel ( A sample for testing was prepared by filling the parts of
Examples 2 and 3 and Comparative Examples 2 and 3 were prepared by filling a transparent ink containing tube made of a polypropylene hollow cylinder having one end connected with a stainless steel ballpoint pen tip holding a carbide ball, did. Table 1 shows the results of tests on bleeding and writing taste.
[0029]
[Table 1]

[0030]
{Circle around (1)} Bleeding test: Write a 20 cm straight line on writing paper A (JIS P3201), observe the handwriting between 10 and 11 cm with a stereomicroscope, and measure the handwriting width of the part without bleeding at five locations. Next, it was calculated how many percent of the average value of the handwriting width corresponds to the average value obtained by measuring five lengths of the same range of bleeding (portion where the ink moved along the paper fiber).
[0031]
{Circle around (2)} Initial writing taste test: The lightness of writing feel was evaluated by sensory evaluation when 10 circles having a diameter of 2 cm were continuously written on writing paper A (JIS P3201) by hand.
[0032]
(3) Writing test over time: Lightness of writing when writing 10 circles with a diameter of 2 cm on writing paper A (JIS P3201) by hand using each ball-point pen sample after 2 months at 50 ° C. It was evaluated by sensuality.
[0033]
As described in detail above, the water-based ballpoint pen ink according to the present invention is excellent in maintaining smooth and light writing after aging with little bleeding.

Claims (1)

A water-based ink for ballpoint pens comprising at least a colorant, water, and an oligomer of 2,5-dimercapto-1,3,4-thiadiazole .