JP3804287B2 - Water-based ink for writing instruments - Google Patents

Description

＊１：インキ中に添加した架橋型Ｎ−ビニルカルボン酸アミドと、ニトロ基、スルホン基、カルボキシル基、ニトリル基のうち１種又は２種以上を有するアルキル基と、脂肪族複素環としてピペラジノ基、ピペリジノ基、ピペリジニル基、モルホリノ基のいずれかとを有する低分子化合物との比率
【００３５】
【表２】

【００３６】
【発明の効果】
以上、詳細に説明したように、本発明に係る水性インキは、筆記具用水性インキを加熱したり経時等をした場合の粘度上昇を緩和することにより、吐出量の変化、筆記時のカスレ等の発生を極力抑制し、インキを使い切るまで良好な筆跡が得られることを可能となしたものである。[0001]
BACKGROUND OF THE INVENTION
  The present invention relates to a water-based ink for writing instruments that suppresses changes in the discharge amount and the occurrence of scumming during writing as much as possible by alleviating the increase in viscosity when the water-based ink for writing instruments is heated over a long period of time. .
[0002]
[Prior art]
  Conventionally, a water-based ink for writing instruments is added with a cross-linked poly-N-vinylcarboxylic acid amide for the purpose of preventing good print quality and preventing pigment aggregation over time and obtaining long-term stability. And Japanese Patent Application Laid-Open No. 9-194785. In addition, in the inks described in these publications, an activator, a polymer pigment dispersant, a water-soluble resin, and the like are used in addition to the crosslinked polyN-vinylcarboxylic amide.
[0003]
[Problems to be solved by the invention]
  However, water-based inks using cross-linked poly-N-vinylcarboxylic acid amides can be used as pigment dispersants, dye solubilizers, and fixing agents for these colorants when subjected to prolonged aging or heating. The viscosity of the ink itself may increase by reacting with other ink composition components such as an agent. When the viscosity of the ink increases, there is a problem that ink supply from the ink reservoir of the writing instrument to the pen tip does not work well, and the ink discharge amount is reduced to cause blurring during writing.
[0004]
  The object of the present invention is to reduce the increase in viscosity when heating water-based ink for writing instruments over a long period of time, heating, etc., thereby minimizing the change in discharge amount and the occurrence of scumming during writing, and the like. Is to provide.
[0005]
[Means for Solving the Problems]
  The present invention includes at least water, a colorant, a crosslinked poly-N-vinylcarboxylic amide, an alkyl group having one or more of nitro group, sulfone group, carboxyl group, and nitrile group, and, A low molecular compound having any one of a piperazino group, a piperidino group, a piperidinyl group, and a morpholino group as an aliphatic heterocyclic ringA water-based ink for a writing instrument consisting of
[0006]
  As the colorant, both dyes and pigments conventionally used in water-based inks can be used without limitation, but specific examples thereof include 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 (same 38), direct deep black (similar to 38), direct fast black conch (same 51), Kayara Spragley VGN (71), kayak direct brilliant yellow G (C.I.). I. Direct Yellow 4) Direct Fa Toero 5GL (same as 26), Eisen Burimuraero GCLH (same as 44), Direct Fast Yellow R (same as 50), Eisen Direct Fast Red FH (CI Direct Red 1), Nippon Fast Scarlet GSX (same as 4), Direct Fast Scarlet 4BS (same as 23), Eisen Direct Durin BH (same as 31), Direct Scarlet B (same as 37), Kayak Direct Scarlet 3B (same as 39), Eisen Buri Murabin Conk 2BLH (same as 75), Sumilite Red F3B (Eighth), Eisen Blomula Red 4BH (Same 81) Calas Spral Bin BL (83), Calas Light Red F5G (225), Calas Light Red F5B (226), Calas Light Rose FR ( 227) Daire Tosky Blue 6B (CI Direct Blue 1), Direct Sky Blue 5B (15), Benzo Brilliant Sky Blue 8GS (41), Sumilite Spula Blue BRR Conch (71), Dibogen Turquoise Blue S ( 86), Water Blue # 3 (86), Kayara Star Coyze Blue GL (86), Daiwa Blue 215H (87), Kayala Supra Blue FF2GL (106), Kayara Supra Blue FFRL (108) Direct dyes such as Caillas splatter turquoise blue FBL (199), Acid Blue Black 10B (CI Acid Black 1), Nigrosine (2), Water Black R455 (2), Water Black R510 (2) ), Suminol Milling Black 8BX (same as above) 24), Kayanol Milling Black VLG (26), Kayanol 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 Conc (107), Kayanol Milling Black TLB (109), Suminol Milling Black B (109), Kayanol Milling Black TLR (110), Eisen Opal Black New Concord (same as above) 119), Water Black 187-L (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 Noor Milling Yellow G (78), Kayanol Yellow N5G (110), Sumino Milling Yellow 4G 200% (same as 141), Kayanol Yellow NG (same as 135), Kayanol Milling Yellow 5GW (same as 127), Kayano Milling Yellow 6GW (same as 142), Sumitomo Fast Scarlet A (C.I. 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) No. 26), Daiwa Red No. 2 (No. 27), Suminol Leveling Brilliant Red S3B (No. 35), Kayasil Lubinol 3GS (No. 37), Eisen Erythrosine (No. 51), Kayaku Acid Rhodamine FB (No. 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 (same 27), acidic dyes such as Water Orange # 17 (CI Acid Orange 56), Water Yellow # 2 (CI Food Ero-3), Food Yellow 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.
[0007]
  As the pigment, conventionally known pigments can be used. Specific examples include Special Black 6, S170, S610, 5, 4, 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 Kasei) Industrial Co., Ltd.), MONARCH 1300, 1100, 1000, 900, 880, 800, 700, MOGULL, REGAL 400R, 660R, 500R, 330R, 300R, 99R, ELFEX8, 12, BLACK PEARLS 2000 (above, manufactured by Cabot Co. LTD, USA), Raven7000, 5750, 5250, 5000, 3500, 2000, 1500, 1255, 1250, 1200, 1170, 1060, 1040, 1035, 1020, 1000, 890H, 890, 850, 790, 780, 760, 500, 450, 430, 420, 410, 22, 16、14、825 OilBeads 、 H20 、 Carbon black, KA-10, 10P, 15, 20, 30, 30, 35, 60, etc., C, Conductex 975, 900, SC (above, Colombian Carbon Japan Co., Ltd.) 80, 90, KR-310, 380, 460, 480 (above, manufactured by Titanium Industry Co., Ltd.), P25 (manufactured by Nippon Aerosil Co., Ltd.), etc., BS-605, 607 ( As mentioned above, Toyo Aluminum Co., Ltd.), Bronze Powder P-555, P-777 (above, 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, chromium oxide, Hansa A-10G, 5G, 3G, 4, 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, Examples include organic pigments such as phthalocyanine green. In addition to these, inorganic fluorescent pigments such as zinc sulfide, zinc silicate, zinc cadmium sulfate, calcium sulfide, strontium sulfide, and calcium tungstate are listed.
  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 when the amount is small, the color development of the ink is poor, and when the amount is large, the colorant is insufficiently dissolved / dispersed. Since defects occur, the content is preferably 0.1 to 40% by weight based on the total amount of water-based ink.
[0008]
  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 resins or water-soluble resins, anionic or nonionic surfactants are generally used. What is used as a dispersant for pigments such as 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 polymers such as lignin sulfonate and shellac , Polyacrylate, salt of styrene-acrylic acid copolymer, salt of vinyl naphthalene-maleic acid copolymer, sodium salt of β-naphthalenesulfonic acid formalin condensate, phosphate, etc. 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. When the amount used is small, the dispersion effect, which is the purpose of addition, is weak, and when there is a large amount, the dissolution balance of each composition in the ink may be lost and various problems may occur. 1 to 20% by weight is preferred.
[0009]
  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, 8276, 8276, 8381, 8406, Fuji SP Red 5096, 5111, 5193, 5220, FujiSP 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, FujiSP Orange 534, FUJ SP Brown 3074 (above, Fuji B) FB, KR, Emacol Green LXB, EmacolViolet BL, Emacol Brown 3101, Emacol Carmine FB, Emacol Red BS, Emacol Orange R, Emacol Yellow FD, IRN, 3601, FGN, GN, GG, F5G, F7G, 10GN, 10G, Sande C , Sandy Super Gray B, Sandy Super Brown SB, FRL, RR, Sandy Super Green L5G, GXB, Sandye SuperNavy Blue HRL, F-BL, F- Violet BLH / C, BL, Sandy Super Bordeaux FR, Sandy Super Pink FBL, F5 , Sandy SuperRubine FR, Sandy superCarminine FB, Sandy Super Red FFG, RR, BS, Sandy Super Orange FL, R, BO, Sandy GoldYRow G Same FGN, Same GN, Same GRS, Same GSR-130, Same GSN-130, Same GSN, 10 GN (Sanyo Dye Co., Ltd.), RioFastBlack Fx 8012, 8313, 8169, Rio FastRed Fx 8209, 8172, Rio Fast Red S Fx8315, 8316, RioFast Blue FX 8170, RioFast Blue FX 8170, Rio Fa st Blue S Fx 8312, Rio Fast Green SFx 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, and 6559 (above, manufactured by Nippon Fluorescence Corp.), Cosmo Color S1000F Series (produced 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 (above, manufactured by Gokoku Color Co., Ltd.) and the like can be mentioned, and these can be used alone or in combination of two or more.
[0010]
  Various water-soluble organic solvents can be used in addition to water essential as a solvent or a dispersion medium, and these are various qualities as water-based inks, for example, prevention of ink drying at the nib and prevention of ink freezing at low temperatures. It is used for purposes such as pigment dispersion media. 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 and the like can be used, and these can be used alone or in combination of two or more. When the amount used is small, insoluble / aggregates are generated due to insufficient dissolution or dispersion of each composition in the ink, and when the amount used is large, the concentration of each composition in the ink becomes small and the effect is small. Since various problems occur, 5 to 40% by weight is preferable with respect to the total amount of ink.
[0011]
  Cross-linked poly N-vinyl carboxylic acid amide suppresses the fluidity of the ink when it is placed by stabilizing the dispersion by increasing the viscosity of the entire ink and retaining the colorant, and adding thixotropy to the ink. It is used to make it difficult for various problems, such as preventing ink leakage from the nib. The amount of the cross-linked poly-N-vinylcarboxylic acid amide is not generally described in consideration of the interaction with other ink composition components, but if it is small, it has an effect of retaining a colorant and an effect of preventing ink leakage. When the amount is small and large, the ink is excessively thickened and the ink is difficult to be ejected and the blur of the handwriting tends to be remarkable. Therefore, the content is preferably 0.1 to 15.0% by weight with respect to the total amount of the ink.
[0012]
  Low molecular weight compound having an alkyl group having one or more of nitro group, sulfone group, carboxyl group and nitrile group, and any one of piperazino group, piperidino group, piperidinyl group and morpholino group as an aliphatic heterocyclic ringIs used for suppressing the reaction between the cross-linked poly-N-vinylcarboxylic acid amide and other ink composition components. Here, the low molecular compound refers to a compound having a molecular weight of about 100 to 600. Although it is possible to suppress the reaction between the cross-linked poly-N-vinylcarboxylic acid amide and other ink composition components even with a polymer compound, the effect of suppressing the reaction is small even when the polymer compound is added in an increased amount. On the other hand, there is a risk that the ink viscosity rises and as a result, there is a problem that ink discharge is reduced. Therefore, a low molecular compound is preferable.
  Specifically, nitrobutyl morpholine, 4,4 ′-(2-ethyl-2-nitrotrimethylene) dimorpholine, nitropropyl morpholine, nitropentyl morpholine, sulfobutyl morpholine, sulfopropyl morpholine, sulfopentyl morpholine, carboxybutyl morpholine , Carboxypropylmorpholine, carboxypentylmorpholine, cyanobutylmorpholine, cyanopropylmorpholine, cyanopentylmorpholine, nitrobutylpiperazine, nitropropylpiperazine, nitropentylpiperazine, sulfobutylpiperazine, sulfopropylpiperazine, sulfopentylpiperazine, carboxybutylpiperazine, carboxy Propyl piperazine, Carboxypentyl piperazine, Cyanobutyl piperazine, Cyanopropi Piperazine, cyanopentylpiperazine, nitrobutylpiperidine, 4,4 '-(2-ethyl-2-nitrotrimethylene) dipiperidine, nitropropylpiperidine, nitropentylpiperidine, sulfobutylpiperidine, sulfopropylpiperidine, sulfopentylpiperidine, carboxybutyl , Piperidine, carboxypropylpiperidine, carboxypentylpiperidine, cyanobutylpiperidine, cyanopropylpiperidine, cyanopentylpiperidine, etc., those having a sulfone group and a carboxyl group can be used in the form of a salt, and an alkali metal as a salt Salts, alkanolamine salts, ammonium salts, amine salts and the like can be used.
  Low molecular weight compound having an alkyl group having one or more of nitro group, sulfone group, carboxyl group and nitrile group, and any one of piperazino group, piperidino group, piperidinyl group and morpholino group as an aliphatic heterocyclic ringThe amount added is not generally described in consideration of the interaction with other ink compositions, but is preferably 0.01 to 10.0% by weight based on the total amount of the ink. When the amount is less than 0.01% by weight, the effect of suppressing the reaction between the cross-linked poly-N-vinylcarboxylic acid amide and the other ink composition is reduced. When the amount is more than 10.0% by weight, each composition in the ink is reduced. Dissolution or dispersion balance of things collapses and various problems occur.
  Moreover, in order to fully demonstrate the effect of this invention by interaction with bridge | crosslinking type N-polyvinylcarboxylic acid amide, the addition amount of bridge | crosslinking type N-polyvinylcarboxylic acid amide:A low molecular weight compound having an alkyl group having one or more of a nitro group, a sulfone group, a carboxyl group, and a nitrile group and any one of a piperazino group, a piperidino group, a piperidinyl group, and a morpholino group as an aliphatic heterocyclic ringThe addition amount is preferably 10: 1 to 1:10.
[0013]
  In addition to the essential cross-linked poly-N-vinylcarboxylic acid amide, a water-soluble polymer may be used in combination for adjusting the viscosity of the ink or stabilizing the dispersion of the coloring material. Specifically, polyvinyl alcohol, polyvinyl methyl ether, sodium polyacrylate, carboxyvinyl polymer, polyethylene oxide, copolymer of vinyl acetate and polyvinyl pyrrolidone, alkali metal salt of acrylic resin, copolymer of acrylic acid and alkyl methacrylate Natural gum arabic, gum tragacanth, xanthan gum, guar gum, locust bean gum, alginic acid, carrageenan, gelatin, casein, dextran, semi-synthetic methylcellulose, ethylcellulose, hydroxyethylcellulose, carboxymethylcellulose, sodium starch glycolate, sodium alginate, alginic acid Examples include propylene glycol esters and derivatives thereof.
[0014]
  Also, sodium dehydroacetate, 1,2-benzothiazalin-3-one, methyl-2-benzimidazole carbamate, sodium benzoate, etc. to suppress ink outflow inhibition in the ink passage of ink writing instruments due to generation of wrinkles An appropriate amount of antiseptic / antifungal agent can be added.
[0015]
  In addition, in the case of writing instruments that use metal in the parts that come into contact with ink, anticorrosives such as benzotriazole and ethylenediaminetetraacetic acid are added to prevent corrosion of the metal, and fatty acids such as oleic acid are added as a solubilizer. I can do it.
[0016]
  In producing the ink of the present invention, various conventionally known methods can be employed. For example, when a dye is used as a colorant, the mixture is stirred and mixed with a stirrer such as a turbo mixer, and when a pigment is used as a colorant, a disperser such as a ball mill, a sand grinder, a speed line mill, or a roll mill is used. It is easily obtained by mixing and grinding.
[0017]
[Action]
  Low molecular weight compound having an alkyl group having one or more of nitro group, sulfone group, carboxyl group and nitrile group, and any one of piperazino group, piperidino group, piperidinyl group and morpholino group as an aliphatic heterocyclic ringThe reason why the combined use of the cross-linked poly N-vinyl carboxylic acid amide in the ink is effective in suppressing the increase in viscosity after long-term aging and heating of the ink is as follows.
  The cross-linked poly-N-vinylcarboxylic acid amide swells, disperses or dissolves with a solvent or water, but when other ink composition components such as a resin and an activator are added, the functional groups of the other ink composition components are cross-linked. It is considered that the viscosity of the ink is increased by the reaction of the amide group of the poly N-vinyl carboxylic acid amide with the crosslinked poly N-vinyl carboxylic amide being further crosslinked between the molecules.
  When the low molecular weight compound is emulsified, dispersed or dissolved, the amide group of the cross-linked poly N-vinylcarboxylic acid amide and the nitro group, sulfone group, carboxyl group, and nitrile group of the low molecular weight compound are fixed by hydrogen bonding. As a result, functional groups of other ink composition components such as resins and activators react with amide groups of the cross-linked poly N-vinyl carboxylic acid amide to cross-link between the molecules of the cross-linked poly N-vinyl carboxylic acid amide. It is thought that the viscosity does not increase because the state can be suppressed. In addition, since the low molecular weight compound of the present invention has a structure containing an aliphatic heterocyclic ring, it seems that this aliphatic heterocyclic structure prevents steric hindrance and other ink compositions approach and react with the amide group. It is.
  In addition, when it has an aliphatic heterocycle, it is easily soluble in water, which is the main solvent, so even if it forms a hydrogen bond with the cross-linked poly-N-vinylcarboxylic acid amide, there is little effect on its swelling, dispersion, or dissolution, and the viscosity does not increase. It seems to be.
[0018]
【Example】
  Hereinafter, the present invention will be described in detail with reference to examples. The viscosity of each ink shown below is measured with a standard cone rotor 10 rpm manufactured by Tokimec Co., Ltd. when the viscosity is less than 50 cps, and an ELD viscometer standard corn roam manufactured by Tokimec Co., Ltd. is used when the viscosity 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-2. Measurement was performed at 5 rpm. The measurement was performed at 25 ° C.
  In each example, “part” simply means “part by weight”.
[0019]
  Example 1
  MICRO JET BLACK M-800 (black aqueous pigment base, manufactured by Orient Chemical Co., Ltd.) 25.00 parts
  Crosslinked poly N-vinylcarboxylic acid amide 1.40 parts
  Nitrobutylmorpholine 0.25 parts
  4,4 '-(2-Ethyl-2-nitrotrimethylene) dimorpholine
                                                              0.08 parts
  Proxel GXL (preservative, manufactured by ICI Japan) 0.22 parts
  Ethylene glycol 25.00 parts
Glycerin 8.00 parts
  39.55 parts of water
25% Aminomethylpropanediol aqueous solution 0.50 parts
  In each of the above components, cross-linked poly N-vinylcarboxylic acid amide and water are mixed and stirred with a stirrer for 2 hours, and then other components are added and stirred again for 3 hours to obtain a black aqueous ink having a viscosity of 1620 cps. It was.
[0020]
  Example 2
  EM YELLOW G (yellow aqueous pigment base, manufactured by Toyo Ink Co., Ltd.)
                                                            40.00 parts
  Cross-linked poly N-vinylcarboxylic acid amide 0.50 parts
  Nitrobutylpiperazine 1.00 parts
  Propylene glycol 30.00 parts
  28.50 parts of water
  Each component other than the above-mentioned cross-linked poly N-vinyl carboxylic acid amide is mixed and stirred for 1 hour with a stirrer, and then the cross-linked poly N-vinyl carboxylic acid amide is added and stirred again for 3 hours. A yellow aqueous ink having a viscosity of 300 cps was obtained.
[0021]
  Example 3
  Water pink # 2 (dye, manufactured by Orient Chemical Co., Ltd.) 2.00 parts
  Cross-linked poly N-vinylcarboxylic acid amide 0.05 parts
  Nitropropylpiperidine 0.45 parts
  Ethylene glycol 20.00 parts
  Glycine betaine (solubilizing agent) 0.55 parts
  76.95 parts of water
  Other than the cross-linked poly N-vinyl carboxylic acid amide in the above components, after mixing and stirring for 3 hours, the cross-linked poly N-vinyl carboxylic acid amide was added and stirred for 3 hours with a stirrer, and a pink water-based ink having a viscosity of 12 cps. Got.
[0022]
  Example 4
  NKW-6013 (red aqueous pigment base, manufactured by Nippon Fluorescent Chemical Co., Ltd.)
                                                            30.00 parts
  Cross-linked poly-N-vinylcarboxylic acid amide 0.20 parts
  Nitrobutylmorpholine 0.02 parts
  Glycerin 6.20 parts
  53.33 parts of water
  Propylene glycol 10.00 parts
  Proxel GXL 0.25 part
  After mixing and stirring the cross-linked poly-N-vinylcarboxylic acid amide, propylene glycol and water in the above components with a stirrer for 1 hour, the other components were added and stirred again for 3 hours to obtain a red aqueous ink having a viscosity of 27 cps. Got.
[0023]
  Example 5
  MA100 (carbon black, manufactured by Mitsubishi Kasei Corporation) 12.00 parts
  Cross-linked poly N-vinylcarboxylic acid amide 0.12 parts
  Cyanobutyl piperidine 0.60 parts
  Sulfopropylmorpholine 0.10 parts
  Glycerin 2.23 parts
  Sodium dehydroacetate 0.22 parts
  84.73 parts of water
  Components other than the cross-linked poly N-vinyl carboxylic acid amide in the above components were stirred and mixed for 2 hours, then the cross-linked poly N-vinyl carboxylic acid amide was added and stirred again for 3 hours to obtain a black aqueous ink having a viscosity of 35 cps. It was.
[0024]
  Example 6
  JR301 (titanium oxide, manufactured by Teika Co., Ltd.) 22.00 parts
  Cross-linked poly N-vinylcarboxylic acid amide 4.00 parts
  Sulfobutylmorpholine 0.80 parts
  Propylene glycol 20.00 parts
  Pentaerythritol 5.00 parts
  49.00 parts of water
  Components other than the cross-linked poly N-vinyl carboxylic acid amide in the above components were stirred and mixed for 3 hours with a stirrer, then the cross-linked poly N-vinyl carboxylic acid amide was added and stirred again for 2 hours, and a white aqueous solution having a viscosity of 18000 cps. An ink was obtained.
[0025]
  Comparative Example 1
  Except for the nitrobutyl morpholine and 4,4 ′-(2-ethyl-2-nitrotrimethylene) dimorpholine of Example 1, the same amount as in Example 1 was used except that water was added. Got water-based ink.
[0026]
  Comparative Example 2
  A yellow aqueous ink having a viscosity of 242 cps was obtained in the same manner as in Example 2, except that the nitrobutyl piperazine of Example 2 was added and morpholine was added in that amount.
[0027]
  Comparative Example 3
  A pink aqueous ink having a viscosity of 14 cps was obtained in the same manner as in Example 3 except that the amount of polypropylene glycol was added except for the nitropropylpiperidine of Example 3.
[0028]
  Comparative Example 4
  Example 4Except that nitrobutylmorpholine was added, and the amount of cross-linked poly-N-vinylcarboxylic acid amide was added.Example 4In the same manner as above, a red aqueous ink having a viscosity of 30 cps was obtained.
[0029]
  As described above, 0.8 g of the water-based ink obtained in Examples and Comparative Examples was added to a transparent ink containing tube made of a polypropylene hollow shaft cylinder having a stainless ballpoint pen tip (ball material: cemented carbide) connected to one end. Filled and used as a test sample. The ball diameter of the stainless ballpoint pen tip is 0.5 mm for the water-based ink obtained in Example 1 and Comparative Example 1, and for the water-based ink obtained in Example 2 and Comparative Example 2. 0.4mm,Obtained in Example 6It was set to 0.8 mm for water-based ink. Example 34, 5And Comparative Example 3,42.0 g of the water-based ink obtained in the above was filled into a sign pen (S520, manufactured by Pentel Co., Ltd.) using a fiber nib to obtain a test sample.
[0030]
  The test samples described above were tested for the rate of change in ink ejection amount and writing scuffing before and after aging at 50 ° C. for 30 days. Further, the test tubes containing the inks of the examples and comparative examples were similarly aged, and the ink viscosity change rate was measured before and after aging. The results are shown in Tables 1 and 2.
[0031]
Test method
  (1)Ink discharge rate change rate
  Using a self-rotating continuous spiral writing tester (written tester MODEL TS-4C-20 manufactured by Seiki Kogyo Laboratories), writing speed is 7 cm / sec, load is 100 g, writing angle is 70 °, and 10 test samples are each 200 m. Writing continuously, the weight of ink ejected at 0 to 200 m was measured, and the rate of change in ink ejection amount was calculated by the following (Equation 1).
(Formula 1) Rate of change in ink discharge after heating [%] = 100 × (ink discharge before heating-ink discharge after heating) / (ink discharge before heating)
[0032]
  (2) Ink viscosity change rate measurement
  The ink viscosity before and after heating was measured, and the viscosity change rate was calculated by the following (Formula 2).
(Formula 2) Ink viscosity change rate after heating [%] = 100 × (ink viscosity after heating-ink viscosity before heating) / (ink viscosity before heating)
[0033]
  (3) Number of writing spots
  Each of the 10 samples was subjected to a writing test up to 400 m under the same conditions as the ink discharge rate change rate test, and the number of pens on which the blur occurred was measured.
[0034]
[Table 1]

* 1: Cross-linked N-vinylcarboxylic amide added to the ink,Low molecular weight compound having an alkyl group having one or more of nitro group, sulfone group, carboxyl group and nitrile group, and any one of piperazino group, piperidino group, piperidinyl group and morpholino group as an aliphatic heterocyclic ringRatio with
[0035]
[Table 2]

[0036]
【The invention's effect】
  As described above in detail, the water-based ink according to the present invention reduces the increase in viscosity when the water-based ink for writing instruments is heated or over time, etc. The generation is suppressed as much as possible, and good handwriting can be obtained until the ink is used up.

Claims (1)

At least water, a colorant, a crosslinked poly-N-vinylcarboxylic acid amide, an alkyl group having one or more of nitro group, sulfone group, carboxyl group, and nitrile group, and piperazino as an aliphatic heterocyclic ring A water-based ink for a writing instrument comprising a low-molecular compound having any one of a group, a piperidino group, a piperidinyl group, and a morpholino group .