JP2005082613A - Aqueous ink - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide aqueous ink which can provide ink which shows little bleeding and high color development on plain paper and shows a sufficient color development and fixability on paper for exclusive use, and further exerts an excellent discharge stability and produces a printed line having a sufficient width in inkjet recording. <P>SOLUTION: The aqueous ink contains at least a coloring material and a compound of formula (1): R<SB>1</SB>-(EO)<SB>1</SB>-(PO)<SB>m</SB>-(EO)<SB>n</SB>-H (wherein R<SB>1</SB>is a 4-20C alkyl group; 1 is 0.5-3 on average; m is 1-10 on average; n is 1-20 on average; E is an ethylene group; and P is a propylene group) and further contains a surfactant, glycol ether, 1,2-alkylene glycol and 2-pyrrolidone. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a water-based ink capable of obtaining high print quality with respect to plain paper, recycled paper or coated paper and having excellent storage stability.

  Inkjet recording is a method of recording characters and figures on the surface of a recording medium by ejecting ink as small droplets from fine nozzles. As an ink jet recording method, an electrostrictive element is used to convert an electrical signal into a mechanical signal, and ink stored in the nozzle head portion is intermittently ejected to record characters and symbols on the surface of the recording medium. A method of recording characters and symbols on the surface of the recording medium, etc. by rapidly heating a part of the ink that is stored in the vicinity of the ejection part to generate bubbles and intermittently ejecting the volume due to the bubbles. It has been put into practical use.

  The ink used for such ink jet recording has no bleeding, good drying properties, can be printed uniformly on the surface of various recording media, and has multiple colors such as color printing. In the printing of the system, characteristics such as that adjacent colors do not mix are required.

  In conventional inks, many of the inks that use pigments, in particular, have been studied to ensure the print quality by suppressing ink wetting on the paper surface mainly by suppressing penetrability and keeping ink droplets near the paper surface. Has been put to practical use.

  However, ink that suppresses wetting of paper has a large difference in bleeding due to the difference in the type of paper, and in particular, recycled paper containing various paper components causes bleeding due to differences in the wetting characteristics of the ink for each component. To do. In addition, such an ink has a problem that it takes time to dry the print, and there is a problem that adjacent colors are mixed in multicolor printing such as color printing. Further, an ink using a pigment as a coloring material However, since the pigment remains on the surface of paper or the like, there is a problem that the abrasion resistance is deteriorated.

  In order to solve such problems, attempts have been made to improve the permeability of ink into paper. Addition of diethylene glycol monobutyl ether as disclosed in US Pat. No. 5,156,675 (see Patent Document 1), US Patent Addition of Surfynol 465 (manufactured by Nissin Chemical), which is an acetylene glycol-based surfactant, as in US Pat. No. 5,183,502 (see Patent Document 2), or US Pat. No. 5,196,056 (see Patent Document 3) Thus, addition of both diethylene glycol monobutyl ether and Surfynol 465 has been studied. Alternatively, US Pat. No. 2,083,372 discusses the use of diethylene glycol ethers for ink.

  In addition, in inks using pigments, it is generally difficult to improve the penetrability of the ink while ensuring the dispersion stability of the pigment, and the range of selection of penetrants is narrow. Examples using triethylene glycol monomethyl ether as a pigment as disclosed in JP-A-56-147661 (see Patent Document 4) and ethers of ethylene glycol, diethylene glycol or triethylene glycol as disclosed in JP-A-9-111165 (see Patent Document 5) There are also examples using.

US Pat. No. 5,156,675 US Pat. No. 5,183,502 US Pat. No. 5,196,056 Japanese Patent Application Laid-Open No. 56-147861 Japanese Patent Laid-Open No. 9-111165

  However, conventional water-based inks have insufficient print quality, and are often blurred when printed on plain paper such as PPC paper, and color density and color developability are also insufficient. In addition, a dispersion using a conventional general dispersant is unstable, and when a substance having a hydrophilic part and a hydrophobic part such as a surfactant or glycol ether is present, adsorption / desorption is likely to occur. There is a problem of poor storage stability. Ordinary water-based inks need a substance having a hydrophilic part and a hydrophobic part, such as a surfactant and glycol ether, in order to reduce bleeding on paper. Ink that does not use these substances has insufficient permeability to paper, and there is a problem that the type of paper is limited in order to perform uniform printing, which tends to cause a reduction in the printed image.

  Further, additives such as those used in the present invention (acetylene glycol, acetylene alcohol and silicon surfactant, di (tri) ethylene glycol monobutyl ether, (di) propylene glycol monobutyl ether or 1,2- When alkylene glycol or a mixture thereof is used, long-term storage stability cannot be obtained, and ink re-dissolvability is poor, so that the ink is dried and the nozzles of the inkjet head are likely to be clogged.

  In addition, the pigment dispersed by such a dispersant has a problem that the residue of the dispersant remains in the ink system, and the dispersant does not sufficiently contribute to the dispersion and is detached from the pigment and becomes high in viscosity. was there. When the viscosity is high, the amount of coloring material such as pigment is limited, and sufficient image quality cannot be obtained particularly on plain paper.

  Accordingly, the present invention solves such problems, and the object of the present invention is to produce high-color ink with little blur on plain paper, and it is possible to create ink having fixing properties in addition to sufficient color development on special paper. In addition, in the case of ink jet recording, there is a need to provide a water-based ink that has excellent ejection stability and can secure a sufficient line width in printing.

  The water-based ink of the invention contains at least a colorant and a compound represented by the following formula (1).

  As described above, the present invention has low bleeding on plain paper and high color development. In addition to sufficient color development on dedicated paper, it is possible to create a fixing ink. The water-based ink that can secure a sufficient line width in printing can be produced.

  The water-based ink according to the present invention is excellent in stability, has high color development with little blur on plain paper, and can produce ink having fixing property in addition to sufficient color development on special paper. This is based on the result of intensive studies in view of the demand for characteristics such as excellent ejection stability of ink from the head.

  The aqueous ink of the present invention is characterized in that at least a colorant and a compound represented by the following formula (1) are added.

In the compound of the formula (1), R ₁ , an alkyl group having 4 to 20 carbon atoms, l is 0.5 to 3 on average, m is 1 to 10 on average, and n is 1 to 20 on average. When R ₁ , l, m, and n are in the above ranges, bleeding of printed matter can be reduced, and stability as a water-based ink is ensured.

  The compound of formula (1) is specifically marketed as the Neugen XL series of BASF (Germany). Neugen XL40, XL50, XL60, XL70, XL80, XL100 and XL140.

  In the present invention, the colorant means a pigment and a dye. As the colorant, a dye, an organic pigment, or an inorganic pigment can be suitably used.

  For example, dyes classified as acid dyes, direct dyes, reactive dyes, vat dyes, sulfur dyes or food dyes in the color index, as well as colorants classified into oil-soluble dyes and basic dyes. It can also be used. As a pigment for black ink, carbon black (CI pigment black 7) such as furnace black, lamp black, acetylene black and channel black, or copper oxide and iron oxide (CI. Examples thereof include organic pigments such as pigment black 11), metals such as titanium oxide, and aniline black (CI pigment black 1), but carbon black having a relatively low density and difficult to settle in water is preferable for inkjet use. For color inks, C.I. I. Pigment Yellow 1 (Fast Yellow G), 3, 12 (Disazo Yellow AAA), 13, 14, 17, 24, 34, 35, 37, 42 (Yellow Iron Oxide), 53, 55, 74, 81, 83 (Disazo Yellow HR), 93, 94, 95, 97, 98, 100, 101, 104, 108, 109, 110, 117, 120, 128, 138, 153, 180, C.I. I. Pigment Red 1, 2, 3, 5, 17, 22 (Brilliant First Scarlet), 23, 31, 38, 48: 2 (Permanent Red 2B (Ba)), 48: 2 (Permanent Red 2B (Ca)), 48 : 3 (Permanent Red 2B (Sr)), 48: 4 (Permanent Red 2B (Mn)), 49: 1, 52: 2, 53: 1, 57: 1 (Brilliant Carmine 6B), 60: 1, 63: 1, 63: 2, 64: 1, 81 (Rhodamine 6G rake), 83, 88, 101 (Bengara), 104, 105, 106, 108 (Cadmium red), 112, 114, 122 (Quinacridone magenta), 123, 146, 149, 166, 168, 170, 172, 177, 178, 179, 185, 190, 193, 202, 206, 209, 219, . I. Pigment violet 19, 23, C.I. I. Pigment orange 36, C.I. I. Pigment Blue 1, 2, 15 (phthalocyanine blue R), 15: 1, 15: 2, 15: 3 (phthalocyanine blue G), 15: 4, 15: 6 (phthalocyanine blue E), 16, 17: 1, 56 , 60, 63, C.I. I. Pigment Green 1, 4, 7, 8, 10, 17, 18, 36, etc. can be used.

  When used for inkjet in aqueous inks, the amount of these pigments added is preferably 0.5-30%, more preferably 1.0-12%. In order to obtain sufficient color on plain paper such as PPC paper, it is preferable to add 3% or more of pigment. If the addition amount is less than 3%, the print density on plain paper cannot be secured, and if the addition amount exceeds 12%, the viscosity of the ink increases and structural viscosity is generated in the viscosity characteristics, and the ejection stability of the ink from the inkjet head. Tends to get worse.

  The particle size of the pigment is preferably 1 μm or less, more preferably a pigment composed of particles of 0.01 to 0.15 μm, and still more preferably a pigment composed of particles of 0.05 to 0.12 μm.

  As a dispersion method, a dispersion method such as a method using ultrasonic dispersion, nanomizer, jet mill, bead mill, sand mill, roll mill, or the like can be used, but non-media dispersion such as jet mill or nanomizer is preferable because of less contamination. .

  In the present invention, it is preferable to add at least a colorant and a compound of the formula (1). Thereby, sufficient printing quality, storage stability, ejection stability, and sufficient line width and clogging stability in printing can be ensured.

  Moreover, it is good to use a C4-C10 linear or branched 1, 2- alkylene glycol as a penetrant added simultaneously, and it is good that the addition amount is 1.5 to 5%. If it is less than 1.5%, blurring increases and the print quality deteriorates. If it exceeds 5%, the effect of improving the permeability is not so much, the print quality reaches its peak, and the adverse effect of increasing the viscosity tends to occur.

  Also, when using Pigment Black 7 (carbon black), it should be at least 5%, at least 3% for phthalocyanine pigments such as Pigment Blue 15: 3 or 15: 4, and at least 4% for other pigments. Thus, the color developability of plain paper such as PPC paper is ensured.

  Further, it is preferable that at least a surfactant is added to the water-based ink described above. The surfactant is preferably one or more selected from acetylene glycol surfactants, acetylene alcohol surfactants and silicon surfactants. By using these surfactants, bleeding on plain paper is further reduced, and the line width on the dedicated paper can be adjusted to an appropriate level.

  It is preferable to contain 0.1% or more and 5% or less of one or more selected from the above-mentioned acetylene glycol surfactants, acetylene alcohol surfactants and silicon surfactants. For the ink jet ink having low viscosity, small dot diameter, and dynamic behavior, an addition amount that makes the dynamic surface tension 40 mN / m or less is preferable. When the dynamic surface tension exceeds 40 mN / m, bleeding increases. If it exceeds 5%, the effect of the print quality will reach its peak, and even if it is added, the viscosity will increase and it will be difficult to use, ink will easily adhere to the tip of the head, and the print will be disturbed. If it is less than 0.1%, the effect of improving the print quality becomes low. A more preferable addition amount is 0.15 to 2%.

  Further, it is preferable to add at least glycol ether to the above-mentioned water-based ink. With these additions, the drying property of the print is improved, and even if printing is performed continuously, the previous print portion is not transferred to the back side of the next medium. Become.

  The glycol ether is preferably an alkylene glycol having 10 or less repeating units and an alkyl ether having 3 to 10 carbon atoms. Among these, di (tri) ethylene glycol monobutyl ether and / or (di) propylene glycol monobutyl ether are preferable. Moreover, it is preferable that the addition amount of the substance which consists of 1 or more types chosen from the above-mentioned di (tri) ethylene glycol monobutyl ether and (di) propylene glycol monobutyl ether is 0.5% or more and 30% or less. If it is less than 0.5%, the penetrating effect is low and the print quality is not improved. If it exceeds 30%, it becomes difficult to use due to an increase in viscosity, and even if added more than that, there is no effect of improving the printing quality. More preferably, it is 1% or more and 15% or less.

  And at least one selected from the above-mentioned acetylene glycol surfactants, acetylene alcohol surfactants and silicon surfactants, and di (tri) ethylene glycol monobutyl ether and (di) propylene glycol monobutyl ether It is preferable to add one or more selected at the same time. The use of acetylene glycol and / or acetylene alcohol surfactant and at least one selected from di (tri) ethylene glycol monobutyl ether and (di) propylene glycol monobutyl ether causes bleeding on plain paper such as PPC paper. Decreases and print quality improves.

  One or more selected from the above-mentioned acetylene glycol surfactant, acetylene alcohol surfactant and silicon surfactant is 0.1%, and di (tri) ethylene glycol monobutyl ether and (di) One or more selected from propylene glycol monobutyl ether is preferably 1% or more. One or more selected from acetylene glycol surfactants, acetylene alcohol surfactants and silicon surfactants have the effect of improving permeability in small amounts. Therefore, it is 0.5% or less, and at least one selected from di (tri) ethylene glycol monobutyl ether and (di) propylene glycol monobutyl ether is 1% or more, so that the print quality is further improved.

  Further, in the present invention, it is preferable to further add 1,2-alkylene glycol, and among them, 1,2-alkanediol which may be branched having 6 to 7 carbon atoms is preferable. Specifically, 1,2-hexanediol, 4-methyl-1,2-pentanediol, 3-methyl-1,2-pentanediol, 2-methyl-1,2-pentanediol, 1-methyl-1 , 2-pentanediol, 3,3-dimethyl-1,2-butanediol, 1,2-heptanediol, 1,2-octanediol.

  The aqueous ink of the present invention is preferably formed by further adding 2-pyrrolidone. By adding 2-pyrrolidone, ejection stability is improved. The preferable addition amount is 1% or more and 15% or less. If it is less than 1%, the effect of improving the ejection stability is low, and if it exceeds 15%, the improvement of the ejection stability has reached its peak, and the adverse effect of increasing the viscosity tends to occur. More preferably, it is 1.5% or more and 5% or less.

  Further, since the water-based ink of the present invention is water-based and easily perishes, it is preferable to further add a preservative, and the preservative is an alkylisothiazolone, chloroalkylisothiazolone, benzisothiazolone, bromonitroalcohol, One or more selected from oxazolidine compounds and chloroxylenol are preferable. The appropriate value of the addition amount is 0.01% to 1%. If it is less than 0.01%, the antiseptic effect is low, and if it exceeds 1%, the dispersion stability of the molecular colored body tends to deteriorate. A more preferable addition amount is 0.02% to 0.3%. The water-based ink of the present invention preferably further comprises a rust preventive agent, and the rust preventive agent is preferably dicyclohexylammonium nitrate and / or benzotriazole. The appropriate value of the addition amount is 0.005% to 0.5%. If it is less than 0.005%, the antirust effect is low, and if it exceeds 0.5%, the dispersion stability of the molecular colored body tends to be poor. A more preferable addition amount is 0.008% to 0.1%.

  Furthermore, the water-based ink of the present invention is preferably formed by further adding a humectant in order to prevent the ink from drying and clogging in front of the nozzle, and the humectant is a substance having two or more hydroxyl groups. Preferably, it is at least one selected from glycerin, diethylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycol having a number average molecular weight of 400 or less, trimethylol (having 6 or less carbon atoms) alkane, aldose, ketose and sugar alcohol. Is preferred. Examples of aldoses, ketoses and sugar alcohols include monosaccharides and polysaccharides, such as glucose, mannose, fructose, ribose, xylose, arabinose, lactose, galactose, aldonic acid, glucitolose, maltose, cellobiose, sucrose, trehalose, maltotriose, etc. In addition, alginic acid and a salt thereof, cyclodextrins, and celluloses can be used. The appropriate value of the addition amount is 5% to 50%. If it is less than 5%, the moisturizing effect is low, and if it exceeds 50%, the effect as a moisturizing agent reaches its peak, and the viscosity becomes high, which is not preferable. A more preferable addition amount is 8% to 25%.

  The aqueous ink of the present invention preferably further comprises a chelating agent, and the chelating agent is ethylenediaminetetraacetic acid, hydroxyethylenediaminetriacetic acid, glycol etherdiaminetetraacetic acid, nitrilotriacetic acid, hydroxyethyliminodiacetic acid, dihydroxy. Ethylglycine, diethylenetriaminepentaacetic acid, triethylenetetraminehexaacetic acid and salts thereof are preferred. The appropriate value of the addition amount is 0.005% to 1%. If it is less than 0.005%, the chelate effect is low, and if it exceeds 1%, the chelate effect reaches its peak, and the dispersion stability of the molecular color former tends to deteriorate. A more preferable addition amount is 0.01% to 0.3%.

  The ink for inkjet recording in the present invention has a dissolution aid, a permeation control agent, a viscosity modifier, a pH adjuster, a dissolution aid, an antioxidant and an anti-protection agent for the purpose of standing stability and stable ejection from an ink ejection head. Various additives such as glazes may be added.

  Hereinafter, they will be exemplified.

  When the aqueous ink according to the present invention is used for inkjet, it is preferable to add water-soluble glycols in order to suppress drying on the nozzle surface of inkjet or the like. Examples include ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, polyethylene glycol having a molecular weight of 2000 or less, 1,3-propylene glycol, isopropylene glycol, isobutylene glycol, 1,4-butane. Examples include diol, 1,3-butanediol, 1,5-pentanediol, 1,6-hexanediol, glycerin, mesoerythritol, and pentaerythritol.

  When the water-based ink according to the present invention is used for inkjet, the solubility of glycol ethers and ink components which are miscible with water and have low solubility in water contained in the ink is further improved. Alkyl alcohols having 1 to 4 carbon atoms such as ethanol, methanol, butanol, propanol, isopropanol, and the like that can be used to improve the permeability to a recording material such as PPC paper or prevent clogging of nozzles, Ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, ethylene glycol monomethyl ether acetate, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol Mono-n-propyl ether, ethylene glycol mono-iso-propyl ether, diethylene glycol mono-iso-propyl ether, ethylene glycol mono-n-butyl ether, diethylene glycol mono-n-butyl ether, triethylene glycol mono-n-butyl ether, ethylene glycol Mono-t-butyl ether, diethylene glycol mono-t-butyl ether, 1-methyl-1-methoxybutanol, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol mono-t-butyl ether, propylene glycol mono-n-propyl ether, Propylene glycol mono-iso-propyl ether, dipropylene glycol monomethyl ether Glycol ethers such as dipropylene glycol monoethyl ether, dipropylene glycol mono-n-propyl ether, dipropylene glycol mono-iso-propyl ether, propylene glycol mono-n-butyl ether, dipropylene glycol mono-n-butyl ether, formamide , Acetamide, dimethyl sulfoxide, sorbite, sorbitan, acetin, diacetin, triacetin, sulfolane and the like, which can be appropriately selected and used.

  In addition, other surfactants may be added to the ink according to the present invention in order to control the permeability to a medium such as paper or special paper. The surfactant to be added is preferably a surfactant having good compatibility with the ink system shown in this embodiment, and among the surfactants, those having high permeability and stability are preferable. Examples thereof include amphoteric surfactants and nonionic surfactants. Amphoteric surfactants include lauryldimethylaminoacetic acid betaine, 2-alkyl-N-carboxymethyl-N-hydroxyethylimidazolinium betaine, coconut oil fatty acid amidopropyldimethylaminoacetic acid betaine, polyoctylpolyaminoethylglycine and other imidazoline derivatives. is there. Nonionic surfactants include polyoxyethylene nonyl phenyl ether, polyoxyethylene octyl phenyl ether, polyoxyethylene dodecyl phenyl ether, polyoxyethylene alkyl allyl ether, polyoxyethylene oleyl ether, polyoxyethylene lauryl ether, polyoxyethylene Ethers such as ethylene alkyl ether and polyoxyalkylene alkyl ether (polyoxypropylene polyoxyethylene alkyl ether), polyoxyethylene oleic acid, polyoxyethylene oleate, polyoxyethylene distearate, sorbitan laurate, sorbitan mono Stearate, sorbitan monooleate, sorbitan sesquioleate, polyoxyethylene monooleate, Ester such as polyoxyethylene stearate, and the like other fluorine alkyl esters, fluorine-containing surfactants such as perfluoroalkyl carboxylates.

  When the aqueous ink according to the present invention is used for inkjet, amines such as diethanolamine, triethanolamine, propanolamine and morpholine as a pH adjuster, dissolution aid or antioxidant, and their modified products, hydroxylated products Inorganic salts such as potassium, sodium hydroxide, lithium hydroxide, ammonium hydroxide, quaternary ammonium hydroxide (tetramethylammonium, etc.), potassium carbonate (hydrogen), potassium carbonate (hydrogen), lithium carbonate (hydrogen), etc. Carbonates and other phosphates, ureas such as N-methyl-2-pyrrolidone, urea, thiourea and tetramethylurea, allophanates such as allophanate and methyl allophanate, biurets such as biuret, dimethylbiuret and tetramethylbiuret Kind Etc., and the like can be used L- ascorbic acid and salts thereof. In addition, when the aqueous ink according to the present invention is used for inkjet, commercially available antioxidants, ultraviolet absorbers and the like can also be used. Examples include Ciba-Geigy Tinuvin 328, 900, 1130, 384, 292, 123, 144, 622, 770, 292, Irgacor 252, 153, Irganox 1010, 1076, 1035, MD1024, or lanthanide oxides.

  Further, when the water-based ink according to the present invention is used for inkjet, the viscosity modifiers include rosins, alginic acids, polyvinyl alcohol, hydroxypropylcellulose, carboxymethylcellulose, hydroxyethylcellulose, methylcellulose, polyacrylate, polyvinylpyrrolidone. , Arabic gum starch and so on.

  Furthermore, when the water-based ink according to the present invention is used for inkjet in the present invention, the polymer that contributes to the dispersion of the pigment is preferably 0.5% or more in the case of an organic pigment from the viewpoint of fixability. The hydrophobic group of the substance forming the polymer is preferably at least one selected from an alkyl group, a cycloalkyl group or an aryl group. The hydrophilic group of the substance having a hydrophilic functional group is preferably at least a carboxyl group, a sulfonic acid group, a hydroxyl group, an amino group, an amide group, or a base thereof. As specific examples of the substances forming these dispersion polymers, monomers and oligomers having an acryloyl group, methacryloyl group, vinyl group or aryl group having a double bond can be used. For example, styrene, tetrahydrofurfuryl acrylate, butyl methacrylate, (α, 2,3 or 4) -alkylstyrene, (α, 2,3 or 4) -alkoxystyrene, 3,4-dimethylstyrene, α-phenylstyrene, divinyl Benzene, vinyl naphthalene, dimethylamino (meth) acrylate, dimethylaminoethyl (meth) acrylate, dimethylaminopropyl acrylamide, N, N-dimethylaminoethyl acrylate, acryloylmorpholine, N, N-dimethylacrylamide, N-isopropylacrylamide, N, N-diethylacrylamide, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, ethylhexyl (meth) acrylate, other alkyl (meth) Chryrate, methoxydiethylene glycol (meth) acrylate, ethoxy group, propoxy group, butoxy group diethylene glycol or polyethylene glycol (meth) acrylate, cyclohexyl (meth) acrylate, benzyl (meth) acrylate, phenoxyethyl (meth) acrylate, isobonyl (meth) ) Acrylate, hydroxyalkyl (meth) acrylate, other fluorine-containing, chlorine-containing, silicon-containing (meth) acrylate, (meth) acrylamide, maleic acid amide, (meth) acrylic acid, etc., in addition to a monofunctional cross-linked structure In the case (mono, di, tri, tetra, poly) ethylene glycol di (meth) acrylate, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,8-octa Di (meth) acrylate such as diol and 1,10-decanediol, trimethylolpropane tri (meth) acrylate, glycerin (di, tri) (meth) acrylate, di (meth) acrylate of ethylene oxide adduct of bisphenol A or F, A compound having an acrylic group or a methacrylic group such as neopentyl glycol di (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol hexa (meth) acrylate, or the like can be used.

  Further, when the water-based ink according to the present invention is used for inkjet, it is selected from the group consisting of polyacrylic acid ester, styrene-acrylic acid copolymer, polystyrene, polyester, polyamide, polyimide, silicon-containing polymer, and sulfur-containing polymer. It is also possible to prepare these polymers while adding one or more of them as a main component.

  When the aqueous ink according to the present invention is used for inkjet, the polymerization initiator in the present invention is not only potassium persulfate or ammonium persulfate, but also hydrogen persulfate, azobisisobutyronitrile, benzoyl peroxide, dibutyl peroxide, Common initiators used for radical polymerization such as peracetic acid, cumene hydroperoxide, t-butyl hydroxy peroxide, paramentane hydroxy peroxide can be used.

  When the water-based ink according to the present invention is used for inkjet, a chain transfer agent can be used in the emulsion polymerization in the present invention. For example, in addition to t-dodecyl mercaptan, n-dodecyl mercaptan, n-octyl mercaptan, xanthogens such as dimethylxanthogen disulfide, diisobutylxanthogen disulfide, dipentene, indene, 1,4-cyclohexadiene, dihydrofuran, xanthene It is done.

<Example>
Next, a specific embodiment will be described by taking the case of ink for inkjet recording as an example. In the present invention, the case where a pigment is used as a colorant will be described.

(Manufacture of pigment dispersion)
First, the dispersion 1 uses Monarch 880 (manufactured by Cabot), which is carbon black. The reaction vessel equipped with a stirrer, thermometer, reflux tube and dropping funnel was purged with nitrogen, and then 20 parts of styrene, 5 parts of α-methylstyrene, 15 parts of butyl methacrylate, 10 parts of lauryl methacrylate, 2 parts of acrylic acid, t-dodecyl Add 0.3 part of mercaptan and heat to 70 ° C., separately prepared 150 parts of styrene, 15 parts of acrylic acid, 50 parts of butyl methacrylate, 1 part of t-dodecyl mercaptan, 20 parts of methyl ethyl ketone and 3 parts of azobisisobutyronitrile. Is placed in a dropping funnel and the dispersion polymer is polymerized while being dropped into the reaction vessel over 4 hours. Next, methyl ethyl ketone is added to the reaction vessel to prepare a dispersed polymer solution having a concentration of 40%.

  40 parts of the above dispersion polymer solution and 30 parts of Monarch 880 (manufactured by Cabot) which is a carbon black pulverized with Nanomizer (manufactured by Yoshida Kikai Kogyo) for 1 hour, 100 parts of 0.1 mol / L sodium hydroxide aqueous solution, 30 parts of methyl ethyl ketone Are mixed and stirred with a homogenizer for 30 minutes. Thereafter, 300 parts of ion-exchanged water is added and further stirred for 1 hour. Then, the whole amount of methyl ethyl ketone and a part of water were distilled off using a rotary evaporator, neutralized with 0.1 mol / L sodium hydroxide, adjusted to pH 9, and filtered through a 0.3 μm membrane filter. Thus, Dispersion 1 having a solid content (dispersion polymer and carbon black) of 20% is obtained. Dispersions 2 to 4 are obtained in the same manner as above. As the dispersion 2, Pigment Blue 15: 4 (manufactured by Clariant) is used. As the dispersion 3, Pigment Red 122 (manufactured by Clariant) is used. As the dispersion 4, Pigment Yellow 74 (manufactured by Clariant) is used. The numbers shown in () represent the average particle diameter of the pigment in nm units.

(Creation of ink for ink jet recording)
Neugen XL-40 (manufactured by BASF) was used as the compound of the formula (1).

Aqueous ink A addition amount (%)
Neugen XL-40 3.0
Orphin E1010 (manufactured by Nissin Chemical) 0.6
2-pyrrolidone 2.0
Triethylene glycol 2.0
Trimethylolpropane 6.0
Glycerin 8.0
Ethylenediaminetetraacetic acid 2Na salt 0.02
Benzotriazole 0.01
Methyl isothiazolone 0.02
Octyl isothiazolone 0.01
Ion-exchanged water 19.27
The above mixture is referred to as ink aqueous solution A.

<Example 1>
Amount added (wt%)
Dispersion 1 (105) 37.5
Ink aqueous solution A 40.0
Triethanolamine 0.8
Ion exchange water

<Example 2>
Dispersion 2 (85) 22.5
Ink aqueous solution A 40.0
Ion exchange water

<Example 3>
Dispersion 3 (90) 27.5
Ink aqueous solution A 40.0
Ion exchange water

<Example 4>
Dispersion 4 (80) 25.0
Ink aqueous solution A 40.0
Ion exchange water

<Example 5>
Dispersion 1 (105) 15.0
In the ink aqueous solution A, Neugen XL40 was changed to Neugen XL50. 40.0
Triethanolamine 0.9
Ion exchange water

<Example 6>
Dispersion 2 (90) 25.0
In the above ink aqueous solution A, Neugen XL40 was changed to Neugen XL60. 40.0
Ion exchange water

<Example 7>
Dispersion 3 (90) 25.0
In the above ink aqueous solution A, Neugen XL40 was changed to Neugen XL80. 40.0
Ion exchange water

<Example 8>
Dispersion 4 (95) 27.5
In the ink aqueous solution A, Neugen XL40 is changed to Neugen XL140.
Ion exchange water

  The composition of the ink used in the comparative example is as follows. The pigment shown in the comparative example was carbon black dispersed using a random copolymer styrene acrylic acid dispersant. The average particle size of the pigment is shown in () in nm units.

(Comparative Example 1)
Water-soluble pigment 9 (90) 5.0
Glycerin 10.0
Dispersant 3.0
Nonionic surfactant 1.0
Ion exchange water

(Comparative Example 2)
Water-soluble dye (food black 2) 5.5
DEGmME 7.0
Diethylene glycol 10.0
2-pyrrolidone 5.0
Residual amount of ion-exchanged water DEGmME: Diethylene glycol monomethyl ether

(Comparative Example 3)
Water-soluble pigment 11 (110) 5.5
Water-soluble dye (Food Black 2) 2.5
Diethylene glycol 10.0
Nonionic surfactant 1.0
Ion exchange water

  The dispersion pigments and water-soluble dyes of the above comparative examples show net amounts, diethyl sulfonic acid Na is used as a nonionic surfactant, a general acrylic styrene dispersant is used as a dispersant, and a bead mill is used for 2 hours. Created by dispersion.

  Table 1 shows the bleeding evaluation result as the printing quality when characters are printed as the printing evaluation result. Printing evaluation is measured by using an ink jet printer EM-930C manufactured by Seiko Epson Corporation. The index of blur evaluation is 8 dot characters with no "calligraphy" connection A, 1 connection with B, B with 2 connection and 3 connection with C, connection of 4 or more Let D be a certain thing. Here, the term “connection” means a state in which the ink spreads along the fiber of the paper and the horizontal lines of “call” are connected.

  As is apparent from the results in Table 1, it can be seen that the ink used in the comparative example has poor print quality, and that the print quality is good when the ink for ink jet recording used in the present invention is used. The papers used for these evaluations are commercially available papers such as Conqueror paper, Faborit paper, Modo Copy paper, Rapid Copy paper, EPSON EPP paper, Xerox 4024 paper, Xerox 10 paper, Neenha. Bond paper, Rcopyy 6200 paper, Yamayuri paper, Xerox R paper.

  As described above, according to the present invention, it is possible to provide a high-quality and practical ink-jet recording ink in which bleeding of a printed image on a recording medium such as paper is reduced.

  Table 2 shows the evaluation results of the ejection stability. The ejection stability is based on the MS Mincho characters of the Microsoft word on the A4 version Xerox P paper using the Seiko Epson Inkjet Printer EM-930C. 10 for continuous printing of 100 pages at a rate of 2000 characters / page, A for prints with no print disorder, B for prints with less than 10 prints, C for prints with print faults of 10 or more and less than 100 Let D be the print disorder where there is more than one part.

  As can be seen from the results in Table 2, it can be seen that the aqueous ink of the present invention has good ejection stability.

  Table 3 shows the results of evaluating the addition amount of 2-pyrrolidone and the ejection stability from the inkjet head in Examples 1 to 8. The ejection stability is based on the same evaluation method as shown in Table 2.

  As can be seen from the results in Table 3, it can be seen that the addition of 2-pyrrolidone improves the ejection stability.

  Table 4 shows the relationship of clogging when the types and addition amounts of the humectants (triethylene glycol (TEG), trimethylolpropane (TMP) and glycerin (GL)) in Examples 5 to 8 are changed. For clogging, the EM930C cartridge is filled with the inks of Examples 1 to 4 and left in an environment of 20 ° C. and 20% for 3 months to perform a cleaning operation (recover dot missing with a mechanism normally provided in the printer). ) By measuring the number of times all nozzles clogged are recovered. Those that recover in less than 4 times are A, those that recover in 4 to 5 times are B, those that recover in 5 to 10 times are C, and those that do not recover in excess of 10 times are D.

  As can be seen from the results in Table 4, it can be seen that clogging recovery is improved by adding a moisturizing agent. In particular, it can be seen that the amount of moisturizing agent added is 14% or more of the whole and shows good clogging recovery. If the amount of this humectant added is too large, the viscosity will increase, so it must be adjusted accordingly.

  In the present invention, it is preferable to further add a surfactant or glycol ether. It is preferable to add a surfactant or glycol ether as described above to make the dynamic surface tension 40 mN / m or less. In addition to 1,2-hexanediol and olphine E1010 shown in the examples, substances that make the dynamic surface tension 40 mN / m or less include Olphine STG (manufactured by Nissin Chemical Industry) in acetylene glycol surfactants, acetylene Olphine D61 (manufactured by Nissin Chemical Industry) in an alcohol-based surfactant, BYK347, 348 (manufactured by Big Chemie) in a silicon-based surfactant, 4-methyl-1,2-pentanediol (MPD), 1, Examples include 2-hexanediol (1,2-HD), diethylene glycol monobutyl ether (DEGmBE), propylene glycol monobutyl ether (PGmBE), dipropylene glycol monobutyl ether (DPGmBE), and the like. Examples of preferred forms in which these substances are used in place of 1,2-hexanediol and Olphine E1010 shown in Example 1 are given below.

  Orphine STG (manufactured by Nissin Chemical Industry), D61 (manufactured by Nissin Chemical Industry), instead of the compound of formula (1), TEGmBE and Olphine E1010 in the composition of Example 1 and their addition amounts and other additives that may be used in the present invention Shinken Chemical), BYK347 (Big Chemie), 4-methyl-1,2-pentanediol (MPD), 1,2-hexanediol (1,2-HD), diethylene glycol monobutyl ether di (DEGmBE), propylene glycol Additives that may be used in the present invention were added to an ink prepared using a material consisting of one or more selected from monobutyl ether (PGmBE) and dipropylene glycol monobutyl ether (DPGmBE) and the ink shown in Comparative Example 1. In the case (Examples 9 to 18 in Table 5), leave at 70 ° C./1 week as well. Ink generation foreign matter after standing, indicating the examination result of physical properties (viscosity, surface tension) and ejection stability in Table 5. The amount of foreign matter generated is the amount of foreign matter after standing at 70 ° C./initial amount of foreign matter, the viscosity is the viscosity after standing at 70 ° C./initial viscosity, and the surface tension is the value of surface tension after standing at 70 ° C./initial surface tension. Stability is 100 pages of continuous printing of 2000 words / page of MS Mincho characters of Microsoft's word on A4 size Xerox P paper using the ink jet printer EM-930C manufactured by Seiko Epson Corporation at a standard style size of 10 Then, A that does not cause printing disturbances at all is A, B that has printing disturbances of less than 10 places, B that has printing disturbances of 10 to 100 places, and D that has printing disturbances of 100 or more places. Substances such as DEGmBE, E1010, Olphine STG, Olphine D61, BYK347, 4-methyl-1,2-pentanediol (MPD), TEGmBE, PGmBE, and DPGmBE, all of which have good molecular weight, are shown in Table 5. The dynamic surface tension can be reduced with a small amount of addition. The dynamic surface tension was measured using a theta t60 (manufactured by Eihiro Seiki Co., Ltd.) using the maximum bubble pressure method.

  As can be seen from the above results, it can be seen that the aqueous ink according to the present invention has good print quality and becomes an ink for inkjet recording excellent in ejection stability and storage stability. Further, in Examples 2 to 8, when the test was performed in the same manner while changing the additives, almost the same results were obtained. However, when the compound of the formula (1) is not used, the line width when printing using EM930C is 90% or less, a sufficient line width cannot be obtained, and color mixture with other colors increases. When a sufficient line width cannot be obtained, a white streak line is formed in the solid print portion, which is not preferable. Furthermore, this tendency is the same even when polymer fine particles are not used or when a dye is used as a colorant.

The present invention should not be considered to be limited to these examples, and various modifications can be made without departing from the gist of the present invention.

Claims (9)

A water-based ink comprising at least a colorant and a compound represented by the following formula (1).

The aqueous ink according to claim 1, further comprising a surfactant. The aqueous ink according to claim 1, further comprising a glycol ether. The aqueous ink according to claim 1, further comprising 1,2-alkylene glycol. The aqueous ink according to claim 1, further comprising 2-pyrrolidone. The water-based ink according to claim 1, further comprising a humectant. The aqueous ink according to claim 1, further comprising a chelating agent. The water-based ink according to any one of claims 1 to 7, further comprising a preservative. The water-based ink according to claim 1, further comprising a rust preventive agent.