JP2006328422A - Ink for recording and recording method using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ink composition which can achieve the super-high permeation of a pigment ink and effects good image to which the ooze is very little in various recording media, especially a regular paper and a recycled paper, and further in recording media having a gloss layer on its surface. <P>SOLUTION: The aqueous pigment ink composition is characterized by comprising at least a pigment, a water-soluble organic solvent and water, wherein the pigment is dispersible and/or soluble in water without a dispersant having a phenol compound added to the pigment by radical reaction, and comprises a water-soluble cationic polymer or oligomer. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

The present invention is a recording ink, particularly a water-based ink suitable for ink-jet recording, ie, a water-based ink excellent as a color ink for so-called plain paper, and can also be used as a water-based ink for writing instruments, recorders, and pen plotters. It is.
The present invention also relates to an ink composition capable of obtaining high print quality and high reliability for various recording media, particularly plain paper, recycled paper, and special paper having an ink receiving layer on the surface thereof, and particularly coloring. The present invention relates to an ink jet recording ink containing a pigment that can be dispersed and / or dissolved in water without a dispersant and a water-soluble cationic polymer or oligomer.

  Inkjet recording is a method of recording characters and figures on the surface of a recording medium by ejecting ink as small droplets from a fine nozzle. As an ink jet recording method, an electric signal is converted into a mechanical signal using an electrostrictive element, and ink stored in the nozzle head is intermittently ejected to record characters and symbols on the surface of the recording medium, nozzle head A method of recording characters and symbols on the surface of a recording medium by rapidly heating a part of the ink stored in the part to generate a bubble by rapidly heating a part close to the discharge part and then intermittently discharging it by volume expansion due to the bubble. Etc. have been put to practical use.

  Inkjet printers are popular because of their low noise and low running costs, and color printers that can print on plain paper are also on the market. However, it is difficult to satisfy all of the color reproducibility, water resistance, light resistance, image drying, image bleeding and ejection reliability of the image. In particular, in the case of a color printer, even if there is no image quality deterioration in the yellow, magenta, and cyan single color printing portions, image quality deterioration is likely to occur in the two-color overlapping portion of red, green, and blue. In particular, when drying is performed without using a fixing device, since the drying property is improved by increasing the permeability as in the technique described in Patent Document 1 (Japanese Patent Application Laid-Open No. 55-29546), the paper spreads significantly. .

  Conventionally, water-based dye inks containing black dyes have been mainly used as recording liquids for writing instruments and inkjet printers. In recent years, water-based pigment inks using a pigment such as carbon black have been attracting attention in order to impart light resistance and water resistance to recorded images.

  The ink used for such ink jet recording has good printing dryness, no blur of printing, can be printed uniformly on the surface of various recording media, and colors do not mix in the case of multiple colors. The characteristics are required.

  Here, a particular problem is that when paper is used as the recording medium, bleeding occurs mainly due to the mixing of fibers with different permeability, and black ink and color ink are Color mixing at the boundary to lower the image quality, and ink on the recording medium to be peeled off when touched by a hand or the like.

In order to overcome these disadvantages, various ink compositions have been proposed.
For example, Patent Document 2 (JP-B-2-907) uses glycol ether as a wetting agent, Patent Document 3 (JP-B-1-15542) uses water-soluble organic solvent, and Patent Document 4 (Patent Document 4). JP-B-2-3837) proposes the use of a dye dissolution accelerator.

  In addition, Patent Document 5 (US Pat. No. 5,156,675) discloses the addition of diethylene glycol monobutyl ether to improve the permeability, while Patent Document 6 (US Pat. No. 5,183,502) includes acetylene glycol-based surface activity. The addition of Surfinol 465, which is an agent, is further proposed in Patent Document 7 (US Pat. No. 5,196,056), in which both diethylene glycol monobutyl ether and Surfynol 465 are added. Here, diethylene glycol mono-n-butyl ether is also called butyl carbitol and is described in, for example, Patent Document 8 (US Pat. No. 3,291,580). Alternatively, Patent Document 9 (US Pat. No. 2,083,372) discusses the use of ethers of diethylene glycol. Furthermore, Patent Document 10 (Japanese Patent Laid-Open No. 56-147861) proposes the combined use of a pigment and triethylene glycol monomethyl ether.

  Patent Document 11 (Japanese Patent Publication No. 60-23793) discloses that dialkylsulfosuccinic acid as a surfactant has improved drying properties and little image degradation. There is a problem that the decrease is significant, and there is a problem that the active agent is differentiated on the alkali side and the active effect is lost during storage.

  Patent Document 12 (Japanese Patent Publication No. 58-6752) discloses a quick-drying ink with less bleeding by improving the permeability by using a surfactant which is an ethylene oxide adduct having an acetylene bond. ing. However, there is a problem that the drying speed is not improved due to hydrophobic interaction with a direct dye such as DBK168, depending on the dye.

  Patent Document 13 (Japanese Patent Laid-Open No. Sho 56-57862) discloses an ink to which a strongly basic substance is added. Although effective with rosin-sized acidic paper, an alkyl ketene dimer or alkenyl is used. No effect on paper with sulfosuccinic acid as sizing agent. In addition, acid paper is not effective in the two-color overlapping portion.

  Patent Document 14 (JP-A-1-203483) discloses a recording liquid characterized by containing a polyhydric alcohol derivative and pectin, which is obtained by adding pectin as a thickener, Although it prevents bleeding, there is a problem that pectin is nonionic having a hydroxyl group as a hydrophilic group, and thus lacks ejection stability after printing is stopped. Patent Document 15 (JP-A-2-36276) discloses 2-propanol as a component that improves frequency response and fixability, but there are problems with safety such as toxicity and flammability. .

  Patent Document 16 (Japanese Patent No. 2714482) discloses 7 points of diol having a solubility of at least 4.5 parts by weight in 100 parts by weight of water at 25 ° C., but these are highly soluble. Therefore, there is a problem in the lack of function as a penetrant.

  No manufacturer has yet made a penetrating pigment ink formulation, and the only possible formulation is disclosed in Patent Document 17 (Japanese Patent Laid-Open No. 10-95941). An acetylene glycol-based surfinol is used as the surfactant, and a polyhydric alcohol butyl ether is used as the penetrant. However, butyl ethers act on the pigment dispersant to aggregate the pigment, and Surfynol also has an aggregating effect on the surface functional group-added type carbon black.

  In addition, in order to reduce bleeding, it has been studied to heat the recording paper. However, if the recording paper is heated during recording, it takes time to start up the heating unit in the apparatus up to a predetermined temperature, the power consumption of the apparatus main body increases, or the recording paper and other recording media There is a problem of giving damage.

  In addition, in an ink composition using a pigment, an attempt has been made to suppress the penetrability, suppress the ink permeation on the surface of the recording medium, and ensure the print quality. However, if the ink composition does not penetrate into the recording medium to some extent, the pigment may remain on the surface of the recording medium and deteriorate the abrasion resistance. Further, recently, a recording medium having a gloss layer on its surface, giving a gloss to a recorded image, and giving added value to the image has been used. There is a demand for a pigment-based ink that can realize an image having good abrasion resistance on such a recording medium.

  For this type of pigment ink, various brands of carbon black that are commercially available for colorants (for color) are used. Acidic carbon black is considered to have acidic groups such as carboxyl groups on its surface. These are generally vapor or liquid phase oxidation methods using conventional oxidants such as ozone, nitric acid, hydrogen peroxide, and nitrogen oxides, or surface modification methods such as plasma treatment, such as furnace black. It is obtained by appropriately oxidizing carbon black for color.

  Such conventional acidic carbon black or channel black exhibits a certain degree of hydrophilicity, but has insufficient affinity for aqueous medium and dispersion stability, and it is difficult to disperse in water alone. Therefore, when these are used as colorants for aqueous pigment inks, they are dispersed in an aqueous medium using a disperser in the presence of various water-soluble synthetic polymers and so-called pigment dispersants such as surfactants. Need to be stabilized.

  For example, Patent Document 18 (Japanese Patent Laid-Open No. 64-6074) and Patent Document 19 (Japanese Patent Laid-Open No. 4-149286) include acidic carbon black and a dispersant (an anionic surfactant or a polymer dispersant). An aqueous pigment ink containing a buffer is described. Patent Document 20 (Japanese Patent Laid-Open No. 3-210373) describes an ink-jet ink containing acidic carbon black having a volatile content of 3.5 to 8% by weight and a water-soluble anionic polymer. Patent Document 21 (Japanese Patent Laid-Open No. 3-134073) describes an ink jet recording liquid containing neutral or basic carbon black and a water-soluble resin.

  In general, in order to stably generate droplets from the fine tip of an ink jet recording head or to write smoothly with the thin tip of a water-based ballpoint pen, it is possible to prevent ink from solidifying with the orifice of the ink jet recording head or the ballpoint pen tip. It is necessary to.

  However, when using commercially available carbon black like conventional water-based pigment inks, the resin forming the dispersant does not re-dissolve after adhering to the orifice, etc., resulting in clogging and non-ejection of droplets. easy. In addition, since the aqueous pigment ink containing a dispersant is viscous, resistance is generated along the path to the nozzle tip when continuous discharge and high-speed printing are performed over a long period of time, making the discharge unstable and making smooth recording difficult. Furthermore, the conventional aqueous pigment ink has a drawback that the pigment concentration cannot be sufficiently increased in order to ensure ejection stability, and the printing density is insufficient as compared with the aqueous dye ink (recording liquid).

  In order to solve these drawbacks, Patent Document 22 (Japanese Patent Laid-Open No. 9-286938) discloses an aqueous pigment ink containing no dispersant. In the aqueous pigment ink described here, the water dispersibility of carbon black used as a colorant is improved, and does not contain a resin component such as a dispersant. It is said that when used for ink jet recording, nozzle clogging does not occur, and writing can be performed smoothly even from a thin pen tip, and it has sufficient density. There is a big problem.

JP 55-29546 A Japanese Patent Publication No.2-2907 Japanese Patent Publication No. 1-15542 JP-B-2-3837 US Pat. No. 5,156,675 US Pat. No. 5,183,502 US Pat. No. 5,196,056 U.S. Pat. No. 3,291,580 US Pat. No. 2,083,372 Japanese Patent Application Laid-Open No. 56-147861 Japanese Patent Publication No. 60-23793 Japanese Examined Patent Publication No. 58-6752 JP 56-57862 A JP-A-1-203483 JP-A-2-36276 Japanese Patent No. 2714482 Japanese Patent Laid-Open No. 10-95941 JP-A 64-6074 JP-A-4-149286 JP-A-3-210373 JP-A-3-134073 Japanese Patent Laid-Open No. 9-286938

  In view of the above-mentioned problems of the prior art, the object of the present invention is to achieve ultra-high penetration with pigment ink in various recording media, particularly plain paper, recycled paper, and even recording media having a gloss layer on the surface thereof. It is an object of the present invention to provide an ink composition which can realize a good image with very little blurring.

  The above problem is (1) of the present invention, “without a dispersant comprising at least a pigment, a water-soluble organic solvent, and water, wherein a carboxyl group or a sulfone group is added to the pigment by reaction of the pigment with a diazonium salt An aqueous pigment ink composition comprising a water-dispersible cationic polymer or oligomer and a penetrant ", (2)" The pigment is bonded to the surface of It can be dispersed and / or dissolved in water without a dispersant by surface treatment so that at least one functional group of a group, carboxyl group, hydroxyl group, or sulfone group or a salt thereof is bonded. (3) “The pigment is coated with a resin having a hydrophilic part and a hydrophobic part. A water-based pigment ink composition as described in item (1) above, which is a microcapsulated pigment, and (4) “a pigment, a water-soluble organic solvent, and water at least. The pigment is a pigment that can be dispersed and / or dissolved in water without a dispersant in which a phenol compound is added to the pigment by a radical reaction, and contains a water-soluble cationic polymer or oligomer. Pigment ink composition ", (5)" Ink composition according to any one of items (1) to (4), wherein the pigment is mainly composed of carbon black " Product ”, (6)“ Ink composition according to any one of items (1) to (5), wherein the average particle size of the pigment is 300 nm or less ”, (7 ) "The pigment is 2 The ink composition according to any one of the items (1) to (6), wherein the weight of the water-soluble cationic polymer or oligomer is 10% by weight. The ink composition according to any one of items (1) to (7), wherein the average molecular weight is 100,000 or less ", (9)" the water-soluble cationic polymer or oligomer The ink composition according to any one of items (1) to (8), wherein the number average molecular weight is 50,000 or less, and (10) the water-soluble cationic polymer. Or the number average molecular weight of an oligomer is 30,000 or less, The ink composition as described in any one of the above items (1) to (9) ”, (11)“ the water-soluble cation ” A functional polymer or oligomer The ink composition according to any one of (1) to (10), wherein the ink composition is selected from the group consisting of realylamine, polyethyleneimine, and polyvinylamine. The content of the water-soluble cationic polymer or oligomer is 0.1 to 20% by weight based on the total amount of the ink, as described in any one of (1) to (11) above. (13) “The penetrant is a partially water-soluble polyol and / or glycol ether having a solubility of less than 0.1 to 4.5% by weight in water at 25 ° C. The ink composition according to any one of Items (1) to (12), which is contained in an amount of 0.1 to 10.0% by weight based on the total weight of the ink, (14) “25 ° C water A mixture of a partially water-soluble polyol and / or glycol ether and a completely water-soluble polyol / or glycol ether having a solubility of less than 0.1 to 4.5% by weight in the total weight of the recording ink The ink composition according to any one of items (1) to (13), wherein the content is 0.5 to 40% by weight with respect to the resin composition, (15) “partially water-soluble. The ink composition according to any one of (1) to (14), wherein the functional polyol and / or glycol ether is 2-ethyl-1,3-hexanediol. (16) The item (1) to (15), wherein the partially water-soluble polyol is 2,2,4-trimethyl-1,3-pentanediol. Any one Ink composition ", (17)" A completely water-soluble polyol and / or glycol ether is an ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, 1,5-pentanediol, tetra The ink composition according to any one of (1) to (16), wherein the ink composition is at least one selected from the group consisting of ethylene glycol and hexylene glycol. 18) "Further containing a lubricant, the wetting agent is glycerin, and the water-soluble organic solvent is ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, 1,5-pentanediol. , At least one selected from the group consisting of tetraethylene glycol and hexylene glycol, the mixing ratio of the two being in the range of 10: 1 to 1:10 by weight% (1) The ink composition according to any one of items (17) to (17) ", (19)" further contains a lubricant, the wetting agent is glycerin, the water-soluble organic solvent is diethylene glycol, and a mixture of both The ink composition according to any one of (1) to (17), wherein the ratio is in a range of 4: 1 to 1: 4 by weight%. Item (17) or Item (19) is characterized in that the mixed solvent of the lubricant and the water-soluble organic solvent is contained in an amount of 1 to 40% by weight based on the total weight of the recording ink. Ink composition ", (21)" Water The ink composition according to any one of items (1) to (20), wherein the volatile organic solvent is at least one pyrrolidone derivative ”, (22)“ lithium hydroxide, The ink composition according to any one of Items (1) to (21), further comprising a quaternary ammonium salt and triethanolamine ”, (23)“ pH is 7 The ink composition according to any one of the items (1) to (22), wherein the ink composition contains a resin emulsion in the ink. This is solved by the ink composition according to any one of items (1) to (23).

  In addition, the above-described problem is (25) “a recording method for printing on a recording medium by adhering an ink adhering material” according to any one of the items (1) to (24). A recording method using the ink composition according to claim 1], (26) “a recording method in which ink droplets are ejected from a recording head, and the droplets are attached to a recording medium for printing. Thus, the problem is solved by an “ink-jet recording method,” wherein the ink according to any one of items (1) to (24) is used as the ink.

  Furthermore, the above-mentioned problems are solved by (27) “ink for writing instruments comprising the ink composition” of the present invention.

  As is apparent from the detailed and specific description above, according to the present invention, various recording media, particularly plain paper, recycled paper, and even a recording medium having a gloss layer on the surface thereof, can be used with a pigment ink. It is possible to provide an ink composition which can realize a high penetration and a good image with very little bleeding.

  That is, the above problem is that a pigment or radical that can be dispersed and / or dissolved in water without a dispersant in which a functional group such as a carboxyl group is added to the pigment by reaction of a diazonium salt in an aqueous liquid medium. Solved by an ink composition comprising a pigment that can be dispersed and / or dissolved in water without a dispersant in which a phenol compound is added to the pigment by reaction, (ii) a water-soluble cationic polymer or oligomer, and (iii) a penetrant. The

  The inventors of the present invention have recently realized that an ink composition comprising a combination of a specific pigment and a specific penetrating agent, and further a water-soluble cationic polymer or oligomer, achieves ultra-high penetration and effectively suppresses bleeding. The knowledge that a high-quality image excellent in abrasion resistance can be realized was obtained, and all the above problems were solved. The present invention is based on such knowledge.

  An object of the present invention is to provide an ink composition capable of realizing a good image with less blur even on various recording media, particularly plain paper, recycled paper, and even a recording medium having a gloss layer on the surface thereof. . For penetrants in particular, to avoid coagulation with pigments, do not use Surfynol as a surfactant, and do not use butyl ether as a penetrant, and find penetrating ink formulas, particularly ink formulas for pigments. It is in.

  The ink composition according to the present invention comprises at least a pigment, a water-soluble organic solvent, a surfactant, and water, and the pigment can be dispersed and / or dissolved in water without a dispersant. And the penetrant is a partially water-soluble polyol and / or glycol ether having a solubility of less than 0.1 to 4.5% by weight in water at 25 ° C., and a water-soluble cationic polymer or oligomer And an ink composition containing a combination of

  Examples of the recording method using the ink composition according to the present invention include an ink jet recording method, a recording method using a writing instrument such as a pen, and various other printing methods. In particular, the ink composition according to the present invention is preferably used in an ink jet recording method.

  The ink composition according to the present invention includes a pigment, a water-soluble organic solvent, a surfactant, and water, and the pigment is a pigment that can be dispersed and / or dissolved in water without a dispersant. And the penetrant is a partially water-soluble polyol and / or glycol ether having a solubility of less than 0.1 to 4.5% by weight in water at 25 ° C., and a water-soluble cationic polymer Alternatively, the ink composition contains a combination of oligomers. According to the ink composition of the present invention, it is possible to effectively suppress bleeding and realize a high quality image excellent in abrasion resistance. Furthermore, the ink composition according to the present invention has the advantages of excellent print drying and high color density. For example, the ink composition according to the present invention can be applied to a recording method in which printing is performed by dividing the ink amount into two or more times, and according to such a method, printing with a higher density is obtained. be able to.

  The pigment preferably used in the present invention is a surface treatment in which at least one functional group of a carbonyl group, a carboxyl group, a hydroxyl group, or a sulfone group or a salt thereof is bonded to the surface of the pigment without adding a dispersant. It can be dispersed and / or dissolved. Specifically, physical treatment such as vacuum plasma, L. By using a diazoalkyl compound (N═N—R—X) by Studebaker and chemically bonding a functional group such as a carboxyl group, a hydroxyl group or a sulfone group to a carbonaceous material, particularly a carbon black surface, or by a radical reaction It can be obtained by chemically bonding a phenolic compound to a carbonaceous material, particularly carbon black surface, or by grafting a functional group or a molecule containing a functional group onto the surface of carbon black. Unlike conventional surface oxidation methods, the required functional groups can be chemically coupled in the required amount. In the present invention, the functional group grafted on one carbon black particle may be single or plural. The type and degree of the functional group to be grafted may be appropriately determined in consideration of the dispersion stability in the ink, the color density, the drying property on the front surface of the inkjet head, and the like.

  In the present invention, a state where the pigment is stably present in water without a dispersant is expressed as “dispersion and / or dissolution”. In many cases, it is difficult to clearly distinguish whether a substance is dissolved or dispersed. In the present invention, as long as the pigment can exist stably in water without a dispersant, such a pigment can be used regardless of whether the state is dispersed or dissolved. Therefore, in this specification, a pigment that can exist stably in water without a dispersant is sometimes referred to as a water-soluble pigment, but it does not mean that even a pigment in a dispersed state is excluded.

  The pigment used in the present invention is not particularly limited, and an inorganic pigment and an organic pigment can be used. As the inorganic pigment, in addition to titanium oxide and iron oxide, carbon black produced by a known method such as a contact method, a furnace method, or a thermal method can be used. Organic pigments include azo pigments (including azo lakes, insoluble azo pigments, condensed azo pigments, chelate azo pigments), polycyclic pigments (eg, phthalocyanine pigments, perylene pigments, perinone pigments, anthraquinone pigments, quinacridone pigments). , Dioxazine pigments, thioindigo pigments, isoindolinone pigments, quinofullerone pigments, etc.), dye chelates (for example, basic dye type chelates, acidic dye type chelates), nitro pigments, nitroso pigments, aniline black, and the like.

  The type of carbon black used as a raw material is not particularly limited. Any of the above-mentioned acidic carbon black, neutral carbon black, and alkaline carbon black can be used.

  Specific examples of the pigment preferably used in the present invention include the following. For black, carbon black (CI Pigment Black 7) such as furnace black, lamp black, acetylene black, channel black, or metal such as copper, iron (CI Pigment Black 11), titanium oxide And organic pigments such as aniline black (CI Pigment Black 1).

  Specific examples of carbon black include # 10B, # 20B, # 30, # 33, # 40, # 44, # 45, # 45L, # 50, # 55, # 95, # 260, ## manufactured by Mitsubishi Chemical Corporation. 900, # 1000, # 2200B, # 2300, # 2350, # 2400B, # 2650, # 2700, # 4000B, CF9, MA8, MA11, MA77, MA100, MA220, MA230, MA600, MCF88, etc .; Monarch made by Cabot 120, Monarch 700, Monarch 800, Monarch 880, Monarch 1000, Monarch 1100, Monarch 1300, Monarch 1400, Mogal L, Legal 99R, Legal 250R, Legal 300R, Legal 330R, Legal 400R, Legal 500R and Legal 660R, etc .; Made of plastic Printex A, Printex G, Printex U, Printex V, Printex 55, Printex 140U, Printex 140V, Special Black 4, Special Black 4A, Special Black 5, Special Black 6, Special Black 100, Special Black 250 Color Black FW1, Color Black FW2, Color Black FW2V, Color Black FW18, Color Black FW200, Color Black S150, Color Black S160, Color Black S170, and the like.

Further, for color use, 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, 81, 83 (Disazo Yellow HR) ), 95, 97, 98, 100, 101, 104, 408, 109, 110, 117, 120, 138, 153, C.I. I. Pigment orange 5, 13, 16, 17, 36, 43, 51, 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, 209, 219, C I. Pigment violet 1 (rhodamine lake), 3, 5: 1, 16, 19, 23, 38, C.I. I. Pigment Blue 1, 2, 15 (phthalocyanine blue R), 15: 1, 15: 2, 15: 3 (phthalocyanine blue E), 16, 17: 1, 56, 60, 63, C.I. I. Pigment green 1, 4, 7, 8, 10, 17, 18, 36, and the like.
Other pigment pigments (eg carbon) treated with resin, etc., can be dispersed in water, and pigments (eg carbon) can be dispersed in water by adding functional groups such as sulfone groups and carboxyl groups to the surface. Processed pigments can be used.
Further, a pigment may be included in a microcapsule so that the pigment can be dispersed in water.

  Commercially available products can also be used as the pigments preferably used in the present invention. Preferred examples include Cabot carboxyl group-modified CAB-O-JET300, sulfone group-modified CAB-O-JET200, Dainippon Ink. Examples thereof include a microcapsule type pigment dispersion manufactured by Chemical Industries, Ltd., and a pigment dispersion to which a phenol compound is added by a radical reaction.

  The amount of the pigment added to the ink composition is preferably 2 to 10% by weight, more preferably about 4 to 8% by weight.

  The self-dispersing carbon black according to the present invention is generally contained in an amount of 1 to 50% by weight, preferably 2 to 20% by weight, based on the total amount of the aqueous pigment ink. If the carbon black content is less than 1% by weight, the printing or writing density will be insufficient, and if it exceeds 20% by weight, the carbon black will tend to aggregate, causing precipitation during long-term storage, and the ejection stability will be poor. This is because when the amount exceeds 50% by weight, this tendency becomes stronger.

  The average particle size of carbon black in the aqueous pigment ink of the present invention is preferably 300 nm or less, particularly 150 nm or less, and more preferably 100 nm or less. This is because when the average particle size of the carbon black exceeds 300 nm, the precipitation of the pigment tends to occur. Further, it is preferably used as a pigment dispersion having a dispersity of 10 or less.

  The aqueous pigment ink composition of the present invention preferably further contains a water-soluble cationic polymer or oligomer. This is to improve the feathering and color bleeding (boundary bleeding) of the recorded matter after recording with the aqueous pigment ink composition.

  Furthermore, in the aqueous pigment ink containing the aqueous liquid medium of the present invention, self-dispersing carbon black and a water-soluble cationic polymer or oligomer, the water-soluble cationic polymer or oligomer has a weight average molecular weight of 100,000 or less, preferably A cationic polymer or oligomer having a molecular weight of 50,000 or less, or a number average molecular weight of 50,000 or less, preferably 5,000 or less, more preferably 3000 or less. In the molecular structure, an amino group, an imino group, a tertiary amine group, or a fourth polymer. It is preferably selected from the group consisting of polyallylamine having a cationic group such as an ammonium group, polyethyleneimine, polyvinylamine and polyvinylpyrrolidone.

  This water-soluble cationic polymer or oligomer, unlike commonly used pigment dispersants, does not require much performance for dispersing pigments. This is because the self-dispersing carbon black itself has good dispersibility and redispersibility in an aqueous medium.

  Generally, when lipophilic carbon black is dispersed in an aqueous solvent, a hydrophilic group and a lipophilic group must be arranged in a well-balanced manner in the dispersant, and the lipophilic group is strong on the carbon black surface. Must be adsorbed. However, since the water-soluble cationic polymer or oligomer used in the present invention does not need to be adsorbed on the carbon black surface, the lipophilic group may be weaker than a general dispersant.

  However, the dispersion stability and ejection stability of the aqueous pigment ink composition must not be impaired by containing a water-soluble cationic polymer or oligomer. Therefore, in order to avoid solidification of the ink at the orifice and nozzle and quickly re-dissolve it, water-solubility that is easy to wrap and re-dissolve in the form of fine carbon black particles without making carbon black large aggregates when drying It is necessary to use a cationic polymer or oligomer.

  As described above, such water-soluble cationic polymers or oligomers include cationic polymers having a weight average molecular weight in the range of 100,000 or less, preferably in the range of about 50,000 or less. In addition, the number average molecular weight includes 50,000 or less, desirably a polymer or oligomer in the range of 20,000 to 1,000.

  When the average molecular weight of the polymer is 100,000 or more, the viscosity of the ink and the particle size of the dispersion increase, and good ejection stability cannot be obtained. The amine value varies depending on the kind of the cationic polymer and is not particularly limited, but is generally preferably about 5 to 30 (mg eq / g-polymer solid content).

  Examples of the water-soluble cationic polymer or oligomer used in the present invention include polyallylamine represented by the following formula (1), polyvinylamine represented by the formula (2), polyethyleneimine represented by the formula (3), and polyamidine represented by the formula (4) ( Hydrochloride), polyamine sulfone represented by formula (5), and polyimine represented by formula (6).

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(Where n is a positive integer)

（式中、ｎは正の整数である）

(Where n is a positive integer)

（式中、ｍ及びｎは正の整数である）

(Where m and n are positive integers)

（式中、ｎは正の整数である）

(Where n is a positive integer)

（式中、ｎは正の整数である）

(Where n is a positive integer)

（式中、ｍ及びｎは正の整数である）

(Where m and n are positive integers)

  In addition, polyacrylamide cation-modified products, copolymers of acrylamide and cationic monomers, hydroxypropylated polyethyleneimine, polyamide-epichlorohydrin resin, quaternized polyvinylpyridinium, alkylated polyvinylpyrrolidone, etc .; and vinylpyrrolidone monomers, oxazoline Monomers, vinyl oxazolidone monomers, vinyl imidazole monomers homopolymers, and these monomers and general monomers such as acrylamide, methacrylamide, acrylate, methacrylate, tertbutyl acrylate, vinyl ether, acrylonitrile, vinyl acetate, ethylene, styrene, etc. And a copolymer.

  Polyallylamine, polyvinylamine, polyethyleneimine, polyvinylpyrrolidone and the like can be suitably used.

  Further, amine-added epoxy resins, amine-added polybutadiene resins, acrylic amine copolymer resins, amine-added acrylic resins, amine-added methacrylic resins, acrylamide resins, copolymers of acrylamide and cationic monomers, resins having an oxazoline group, cationic groups Water-soluble methacrylamide resin having cation group, methacrylamine copolymer having cation group, cation-modified polyvinyl alcohol, cation-modified cellulose, copolymer of vinyl monomer and vinyl monomer having cationic group Alternatively, cationic urea resins, cationic sizing agents and the like can also be used within the technical scope of the present invention. Moreover, it is also possible to add a nonionic polymer in the range which does not inhibit the effect of this invention as needed.

  Specific examples of the water-soluble cationic polymer or oligomer include polyallylamine (PAA) manufactured by Nitto Boseki Co., Ltd., polyallylamine hydrochloride (PAA-HCl), polyvinylamine (PVAM 0595B) manufactured by Mitsubishi Chemical Corporation, manufactured by Nippon Shokubai Co., Ltd. Polyethyleneimine (Epomin PS-012, PS-200, P-1000) and organic acid salts thereof (hydrochloride, acetate, lactate, etc.).

  These water-soluble cationic polymers or oligomers are 0.1 to 20% by weight based on the total amount of the aqueous pigment ink of the present invention, and 1 to 1 based on the weight of the self-dispersing carbon black contained in the ink of the present invention. It is preferable to add about 10 times.

  The water-based pigment ink of the present invention may contain a water-miscible organic solvent as necessary. In the present specification, water, a water-miscible organic solvent, and a mixture thereof are referred to as an aqueous medium.

  Furthermore, in the aqueous pigment ink of the present invention, additives such as a viscosity modifier, an antifungal agent and a rust preventive agent which are usually used for this kind of ink can be appropriately selected and used in an appropriate amount.

  In addition, the water-based pigment ink of the present invention improves the fixability, print density, and glossiness of the recording paper by adding a water-soluble cationic polymer or oligomer. Further, the re-dissolvability and re-dispersibility of the recording liquid are improved. Alternatively, the dispersion stability is excellent for a long period of time without mechanical dispersion treatment, and re-aggregation of self-dispersing carbon black does not occur. Alternatively, carbon black does not settle in the ink reservoir.

  In addition, the water-based pigment ink of the present invention has good recording / writing characteristics and can be printed at high speed even when used as ink for ink-jet recording or water-based ballpoint pens. There is no fading.

  Furthermore, it is excellent in the fastness (light resistance and water resistance) of characters and figures recorded on plain paper and non-absorbent coated paper, and carbon black does not flow out even when immersed in water again. Even if it is exposed to light, it does not fade or fade like dye inks and has excellent light resistance.

  Furthermore, since carbon black can be contained at a high concentration, the density of the printed matter is excellent, and an optical density equal to or higher than that of the water-soluble black dye is provided.

In the present invention, a partially water-soluble polyol and / or glycol ether having a solubility of less than 0.1 to 4.5% by weight in water at 25 ° C. is 0.1% based on the total weight of the recording ink. Addition of ˜10.0% by weight improves the wettability of the ink to the thermal element, and can provide ejection stability and frequency stability even with a small amount of addition, and safety associated with the use of 2-propanol. The gender problem could also be solved.
The next two points of 1,3-diol are all penetrants having a solubility of less than 0.1-4.5% by weight in water at 25 ° C.

Penetration agent Solubility in water (i) 2-ethyl-1,3-hexanediol 4.2% (20 ° C.)
(ii) 2,2,4-trimethyl-1,3-pentanediol 2.0% (25 ° C.)

A diol having a solubility of at least 4.5 parts by weight in 100 parts by weight of water at 25 ° C. has a high solubility, and thus lacks the function as a penetrant and has a problem in the effect.
In contrast, penetrants having a solubility of less than 0.1-4.5% by weight in water at 25 ° C. have the advantage of very high permeability instead of low solubility. Therefore, a highly penetrating ink can be obtained by combining a penetrant having a solubility of less than 0.1 to 4.5% by weight in water at 25 ° C. with another solvent or another surfactant. It becomes possible to create.

As the partially water-soluble polyol and / or glycol ether having a solubility between 0.1 and 4.5% by weight in water at 25 ° C., 2-ethyl-1,3-hexanediol is particularly preferable. However, other than 2-ethyl-1,3-hexanediol, 2,2,4-trimethyl-1,3-pentanediol, 1,2,4-trimethyl-1,3-pentanediol, ester diol 204, ie HOCH ₂ C (CH ₃ ) ₂ CH ₂ OCOC (CH ₃ ) ₂ CH ₂ OH, hexyl cellosolve ie C ₆ H ₁₂ OCH ₂ CH ₂ OH, hexyl carbitol, ie C ₆ H ₁₃ O (C ₂ H ₄ O) ₂ H and the like are exemplified.

  In addition to the partially water-soluble polyol and / or glycol ether having a solubility between 0.1 and 4.5% by weight in the 25 ° C. water, a completely water-soluble polyol and / or glycol ether It is preferable to use it in order to balance the ink composition.

  Examples of the completely water-soluble polyol include a group consisting of ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, 1,5-pentanediol, tetraethylene glycol and hexylene glycol. And at least one glycol selected from the above.

Examples of the completely water-soluble glycol ether include methyl cellosolve, ie, CH ₃ OC ₂ H ₄ OH, sessolve, ie, C ₂ H ₅ OC ₂ H ₄ OH, and butyl cellosolve, ie, C ₄ H ₉ OC ₂ H ₄ OH. OH etc. are mentioned.

  The partially water-soluble polyol and / or glycol ether is used in an amount of about 0.08 to 10 parts by weight based on 1 part by weight of the completely water-soluble polyol and / or glycol ether.

It is preferable to use the glycerin as a wetting agent and the above water-soluble organic solvent in the range of 10: 1 to 1:10 by weight% in view of the properties of various physical properties in order to balance the ink composition.
In addition, when the wetting agent is glycerin and the water-soluble organic solvent is diethylene glycol, it is particularly preferable that the mixing ratio of both is in the range of 4: 1 to 1: 4 by weight%.
These mixed solvents may be contained in an amount of 1 to 40% by weight based on the total weight of the recording ink. When at least one water-soluble organic solvent is a pyrrolidone derivative, particularly 2-pyrrolidone, the image quality is improved.

  The water-soluble organic solvent used in the present invention forms a main solvent together with water, has compatibility with water, and does not have undesirable interactions with other components in the ink composition. As long as there is no particular limitation.

  The ink of the present invention uses water as a liquid medium. For the purpose of making the ink have desired physical properties, preventing drying of the ink, and improving dissolution stability, for example, The following water-soluble organic solvents are used. A plurality of these water-soluble organic solvents may be used in combination.

Specific examples of the water-soluble organic solvent include the following.
Ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, polypropylene glycol, 1,5-pentanediol, 1,6-hexanediol, glycerol, 1,2,6-hexanetriol, 1,2,4-butanetriol, 1 Polyhydric alcohols such as 2,3-butanetriol and petriol;

  Polyhydric alcohol alkyl ethers such as ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, tetraethylene glycol monomethyl ether, propylene glycol monoethyl ether;

  Polyhydric alcohol aryl ethers such as ethylene glycol monophenyl ether and ethylene glycol monobenzyl ether;

  Nitrogen-containing heterocyclic compounds such as 2-pyrrolidone, N-methyl-2-pyrrolidone, N-hydroxyethyl-2-pyrrolidone, 1,3-dimethylimidazolidinone, ε-caprolactam, γ-butyrolactone;

  Amides such as formamide, N-methylformamide, N, N-dimethylformamide;

  Amines such as monoethanolamine, diethanolamine, triethanolamine, monoethylamine, diethylamine, triethylamine;

  Sulfur-containing compounds such as dimethyl sulfoxide, sulfolane, thiodiethanol;

  Propylene carbonate, ethylene carbonate and the like.

Among these organic solvents, diethylene glycol, thiodiethanol, polyethylene glycol 200 to 600, triethylene glycol, glycerol, 1,2,6-hexanetriol, 1,2,4-butanetriol, petriol, 1,5-pentane Diol, 2-pyrrolidone and N-methyl-2-pyrrolidone are preferred.
These are excellent in solubility and prevention of poor jetting characteristics due to water evaporation.

  In the ink of the present invention, for the purpose of adjusting the surface tension of the ink, a partially water-soluble polyol and / or glycol ether having a solubility of less than 0.1 to 0.45% by weight in water at 25 ° C. Or, in addition to partially water-soluble polyols and / or glycol ethers having a solubility between 0.1 and 0.45% by weight in water at 25 ° C., for example diethylene glycol monophenyl ether, ethylene glycol monophenyl ether, Alkyl and aryl ethers of polyhydric alcohols such as ethylene glycol monoallyl ether, diethylene glycol monobutyl ether, propylene glycol monobutyl ether, tetraethylene glycol chlorophenyl ether, anionic surfactants, nonionic interfaces Sexual agents, fluorine surface active agent, ethanol, can be used lower alcohols such as 2-propanol, especially diethylene glycol monobutyl ether preferable.

The surface tension in the present invention is an index indicating the permeability to paper. In particular, the surface tension indicates the dynamic surface tension in a short time of 1 second or less after the surface is formed, and is different from the static surface tension measured by the saturation time. . As a measuring method, any method can be used as long as it can measure a dynamic surface tension of 1 second or less by a conventionally known method described in JP-A No. 63-31237. In the present invention, a Wilhelmy type suspension plate type is used. It measured using the surface tension meter. The value is preferably from 50 mJ / m ² or less surface tension, and more preferably dry can be obtained and excellent and 40 mJ / m ² or less.

  The pH of the ink composition according to the present invention is preferably controlled in the range of 7 to 11, more preferably 8 to 10. By setting the pH within this range, it is preferable because the pigment and further the resin emulsion described later can be stably present in the ink composition. In addition to the above triethanolamino, the pH can be adjusted with an appropriate alkali agent (for example, an organic alkali such as ammonia and an alkali metal salt). Preferred alkali agents include lithium hydroxide, triethanolamine, and quaternary ammonium salts.

  According to a preferred embodiment of the present invention, the ink composition according to the present invention preferably comprises a water-soluble emulsion. By adding this water-soluble emulsion, it is possible to improve the fixability and abrasion resistance of the print. This water-soluble emulsion is preferably one in which the continuous phase is water and the dispersed phase is an acrylic acid resin, methacrylic acid resin, styrene resin, urethane resin, acrylamide resin, epoxy resin, or a mixed form thereof. In particular, the dispersed phase is preferably made of a resin mainly composed of acrylic acid and / or methacrylic acid. These resins are not limited depending on the mode of copolymerization, and can be, for example, block copolymers, random copolymers, and the like. Furthermore, the water-soluble emulsion used in the ink composition according to the present invention preferably has a film-forming ability, and preferably has a minimum film-forming temperature of room temperature or lower, more preferably 0 ° C. or higher and 20 ° C. or lower. Temperature.

  According to a preferred embodiment of the present invention, the resin component of the water-soluble emulsion is preferably a resin particle having a core-shell structure comprising a core portion and a shell portion surrounding the core portion. For example, it is possible to adopt a configuration in which a resin component capable of improving the finger touch and fixability of the ink is introduced into the core portion, and a resin component that causes the resin particles to stably exist in the ink composition is introduced into the shell portion. . According to a preferred embodiment of the present invention, the core part is preferably made of a resin having a crosslinked structure.

  According to a preferred embodiment of the present invention, the molecular weight of the water-soluble emulsion is preferably 1000 or more, more preferably about 10,000 to 100,000.

  Commercially available products can also be used as the water-soluble emulsion used in the present invention, and examples thereof include Z116 manufactured by Mitsui Toatsu.

  Furthermore, as other commercially available resin emulsions, Microgel E-1002, E-5002 (styrene-acrylic resin emulsion, manufactured by Nippon Paint Co., Ltd.), Boncoat 4001 (acrylic resin emulsion, Dainippon Ink & Chemicals, Inc.) Manufactured), Boncoat 5454 (styrene-acrylic resin emulsion, manufactured by Dainippon Ink & Chemicals, Inc.), SAE-1014 (styrene-acrylic resin emulsion, manufactured by Nippon Zeon Co., Ltd.), Cybinol SK-200 (acrylic resin emulsion) And Seiden Chemical Co., Ltd.).

  Although the addition amount of this water-soluble emulsion may be determined appropriately, for example, it is preferably about 0.5 to 10% by weight, more preferably about 3 to 5% by weight.

  The ink composition according to the present invention may contain other components in addition to the above components. For example, the nozzle clogging preventive agent, preservative, antioxidant, conductivity adjusting agent, pH adjusting agent, viscosity adjusting agent, A surface tension adjusting agent, an oxygen absorbent and the like can be added.

  In the ink composition according to the present invention, saccharides can be added in order to prevent the ink from drying on the front surface of the nozzle. Such saccharides include monosaccharides and polysaccharides, such as glucose, mannose, fructose, ribose, xylose, arabinose, lactose, galactose, aldonic acid, glucitol, maltose, cellobiose, sucrose, trehalose, maltotriose, etc. Examples thereof include alginic acid and salts thereof, cyclodextrins, and celluloses. The addition amount is preferably about 0.05 to 30% by weight. In particular, more preferable addition amount of glucose, mannose, fructose, ribose, xylose, arabinose, lactose, galactose, aldonic acid, glucitol, maltose, cellobiose, sucrose, trehalose, maltotriose, etc. is 3 to 20% by weight. . Depending on the addition amount of alginic acid and its salt, cyclodextrins, and celluloses, the viscosity tends to increase, so it is preferable to reduce the addition amount.

  Further, in order to further control the permeability, it is possible to add another surfactant to the ink according to the present invention. The surfactant to be added is preferably a surfactant having good compatibility with other components in the ink composition, 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 others, imidazoline derivatives, etc. There is. 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, polyoxyethylene oleic acid, polyoxyethylene oleate, polyoxyethylene distearate, sorbitan laurate, sorbitan monostearate, sorbitan monooleate, sorbitan sesquis Esters such as oleate, polyoxyethylene monooleate, polyoxyethylene stearate, etc. Alkyl esters, and the like fluorine-containing surfactants such as perfluoroalkyl carboxylates.

  Examples of the antiseptic and fungicide include sodium benzoate, sodium pentachlorophenol, sodium 2-pyridinethiol-1-oxide, sodium sorbate, sodium dehydroacetate, 1,2-dibenzisothiazoline-3- ON (genexa Proxel CRL, Proxel BDN, Proxel GXL) and the like.

  In addition, as pH adjusters, dissolution aids, and antioxidants, amines such as diethanolamine, triethanolamine, propanolamine, morpholine and their modified products, inorganic substances such as potassium hydroxide, sodium hydroxide, lithium hydroxide, etc. Salts, ammonium hydroxide, quaternary ammonium hydroxide (such as tetramethylammonium), carbonates such as potassium carbonate, sodium carbonate, lithium carbonate, and other phosphates, or N-methyl-2-pyrrolidone, urea, thiourea, Examples include ureas such as tetramethylurea, allophanates such as allophanate and methyl allophanate, biurets such as biuret, dimethylbiuret and tetramethylbiuret, and L-ascorbic acid and salts thereof. Commercially available antioxidants, ultraviolet absorbers, and the like can also be used. Examples include Ciba Geigy's Tinuvin 328, 900, 1130, 384, 292, 123, 144, 622, 770, 292, Irgacor 252, 153, Irganox 1010, 1076, 1035, MD1024 and the like. It is also possible to use an oxide of lanthanide.

  Furthermore, examples of the viscosity modifier include rosins, alginic acids, polyvinyl alcohol, hydroxypropylcellulose, carboxymethylcellulose, hydroxyethylcellulose, methylcellulose, polyacrylate, polyvinylpyrrolidone, gum arabic starch and the like.

Examples of the chelating reagent include sodium ethylenediaminetetraacetate, sodium nitrilotriacetate, sodium hydroxyethylethylenediaminetriacetate, sodium diethylenetriaminepentaacetate, sodium uramil diacetate, and the like.
Examples of the rust inhibitor include acidic sulfite, sodium thiosulfate, ammonium thiodiglycolate, diisopropylammonium nitrite, pentaerythritol tetranitrate, and dicyclohexylammonium nitrite.
Depending on the purpose, a water-soluble ultraviolet absorber, a water-soluble infrared absorber, and a surfactant can be added.

Examples and Comparative Examples of the present invention are shown below, but the present invention is not limited to these. In addition, the amount (%) of each component described in the examples is based on weight.
An ink composition having the following composition was prepared.
[Example 1]
An ink composition having the following formulation was prepared and adjusted with a 10% aqueous solution of lithium hydroxide so that the pH was 9. Then, it filtered with the membrane filter with an average hole diameter of 0.8 micrometer, and obtained the ink composition.
Carboxyl group-added carbon black 5 wt%
CAB-O-JET300
(Cabot Specialty Chemicals, Inc.)
Polyallylamine / Molecular weight 3,000 (Nitto Boseki Co., Ltd.) 1% by weight
Glycerin 5% by weight
Diethylene glycol 15% by weight
2-ethyl-1,3-hexanediol 2% by weight
2-pyrrolidone 2% by weight
ECTD-3NEX 0.3% by weight
(Anionic surfactant manufactured by Nikko Chemicals)
Antifungal agent Sunpack AP 0.3% by weight
Ion exchange water

[Example 2]
An ink composition was prepared in the same manner as in Example 1 except that the following composition was used, and the pH was adjusted to 9 with lithium hydroxide.
Sulfon group-added carbon black 5% by weight
CAB-O-JET300
(Cabot Specialty Chemicals, Inc.)
Polyallylamine / Molecular weight 5,000 (Nitto Boseki Co., Ltd.) 1% by weight
Glycerin 5% by weight
15% ethylene glycol
2-ethyl-1,3-hexanediol 2% by weight
2-pyrrolidone 2% by weight
ECTD-6NEX 0.5% by weight
(Anionic surfactant manufactured by Nikko Chemicals)
Antifungal agent Sunpack AP 0.3% by weight
Ion exchange water

[Example 3]
An ink composition was prepared in the same manner as in Example 1 except that the following composition was used, and the pH was adjusted to 9 with lithium hydroxide.
5% by weight of phenol compound addition type carbon black
Polyallylamine / Molecular weight 10,000 (manufactured by Nitto Boseki Co., Ltd.) 1% by weight
Glycerin 5% by weight
10% by weight of propylene glycol
2-ethyl-1,3-hexanediol 1% by weight
2-pyrrolidone 2% by weight
ECTD-3NEX 1% by weight
(Anionic surfactant manufactured by Nikko Chemicals)
Acrylic resin emulsion Z116 (MFT7 ° C) 3 wt%
(Mitsui Chemicals)
Antifungal agent Sunpack AP 0.3% by weight
Ion exchange water

[Example 4]
An ink composition was prepared in the same manner as in Example 1 except that the following composition was used, and the pH was adjusted to 9 with lithium hydroxide.
Microcapsule-containing carbon black 5% by weight
(Dainippon Ink Chemical Co., Ltd.)
Polyallylamine / Molecular weight 2,000 (Nitto Boseki Co., Ltd.) 1% by weight
Glycerin 5% by weight
Dipropylene glycol 15% by weight
2-ethyl-1,3-hexanediol 2% by weight
2-pyrrolidone 2% by weight
ECTD-6NEX 1% by weight
(Anionic surfactant manufactured by Nikko Chemicals)
Antifungal agent Sunpack AP 0.3% by weight
Ion exchange water

[Example 5]
An ink composition was prepared in the same manner as in Example 1 except that the following composition was used, and the pH was adjusted to 9 with lithium hydroxide.
Carboxyl group-added carbon black 5 wt%
CAB-O-JET300
(Cabot Specialty Chemicals, Inc.)
Polyallylamine / Molecular weight 3,000 (Nitto Boseki Co., Ltd.) 1% by weight
Glycerin 5% by weight
Hexylene glycol 15% by weight
2,2,4-Trimethyl-1,3-pentanediol 2% by weight
2-pyrrolidone 2% by weight
ECTD-3NEX 0.3% by weight
(Anionic surfactant manufactured by Nikko Chemicals)
Antifungal agent Sunpack AP 0.3% by weight
Ion exchange water

[Example 6]
An ink composition was prepared by adjusting the pH to 8 with lithium hydroxide in the same manner as in Example 1 except that the following composition was used.
Sulfon group-added carbon black 5% by weight
CAB-O-JET300
(Cabot Specialty Chemicals, Inc.)
Polyallylamine / Molecular weight 5,000 (Nitto Boseki Co., Ltd.) 1% by weight
Glycerin 5% by weight
15% by weight of triethylene glycol
2,2,4-Trimethyl-1,3-pentanediol 1% by weight
2-pyrrolidone 2% by weight
ECTD-6NEX 0.5% by weight
(Anionic surfactant manufactured by Nikko Chemicals)
Antifungal agent Sunpack AP 0.3% by weight
Ion exchange water

[Example 7]
An ink composition was prepared in the same manner as in Example 1 except that the following composition was used, and the pH was adjusted to 9 with lithium hydroxide.
5% by weight of phenol compound addition type carbon black
(Mitsubishi Chemical Corporation)
Polyallylamine / Molecular weight 10,000 (manufactured by Nitto Boseki Co., Ltd.) 1% by weight
Glycerin 5% by weight
Tetraethylene glycol 15% by weight
2,2,4-Trimethyl-1,3-pentanediol 2% by weight
N-methyl-2-pyrrolidone 2% by weight
ECTD-3NEX 1% by weight
(Anionic surfactant manufactured by Nikko Chemicals)
Antifungal agent Sunpack AP 0.3% by weight
Ion exchange water

[Example 8]
An ink composition was prepared in the same manner as in Example 1 except that the following composition was used, and the pH was adjusted to 8 with lithium hydroxide.
Microcapsule-containing carbon black 5% by weight
(Dainippon Ink Chemical Co., Ltd.)
Polyallylamine / Molecular weight 2,000 (Nitto Boseki Co., Ltd.) 1% by weight
Glycerin 5% by weight
1,5-pentanediol 15% by weight
2,2,4-Trimethyl-1,3-pentanediol 2% by weight
2-pyrrolidone 2% by weight
ECTD-6NEX 1% by weight
(Anionic surfactant manufactured by Nikko Chemicals)
Antifungal agent Sunpack AP 0.3% by weight
Ion exchange water

[Comparative Example 1]
An ink was prepared in the same manner as in Example 1, except that the carboxyl group-added carbon black (CAB-O-JET300) was changed to SA Black 2817-RC (dispersant type pigment dispersion) of Mikuni Dye Co., Ltd.

[Comparative Example 2]
An ink was prepared in the same manner as in Example 2, except that the sulfone group-added carbon black (CAB-O-JET300) was replaced with BONJET BLACK M-800 (dispersant type pigment dispersion) manufactured by Orient Chemical Industries.

[Comparative Example 3]
In Example 3, an ink was prepared in the same manner except that the phenol compound-added carbon black by radical polymerization was changed to Clariant's HOSTAFINE BLACK T (dispersant type pigment dispersion).

[Comparative Example 4]
In Example 4, an ink was prepared in the same manner except that the microcapsule-containing carbon black (Dainippon Ink Chemical Co., Ltd.) was replaced with polytribo AcryJet Black-357 (dispersant type pigment dispersion).

[Comparative Example 5]
Ink was obtained in the same manner as in Example 5 except that polyallylamine / molecular weight 3,000 (manufactured by Nitto Boseki Co., Ltd.) was removed.

[Comparative Example 6]
Ink was obtained in the same manner as in Example 6 except that polyallylamine / molecular weight 5,000 (manufactured by Nitto Boseki Co., Ltd.) was removed.

[Comparative Example 7]
Ink was produced in the same manner as in Example 7 except that polyallylamine / molecular weight 10,000 (manufactured by Nitto Boseki Co., Ltd.) was removed.

[Comparative Example 8]
Ink was obtained in the same manner as in Example 8, except that polyallylamine / molecular weight 2,000 (manufactured by Nitto Boseki Co., Ltd.) was removed.

Next, the following tests were conducted on Examples 1 to 8 and Comparative Examples 1 to 8.
1) Sharpness of image Printing was performed on each of the following papers using an inkjet printer MJ-930C (manufactured by Seiko Epson Corporation). As for the printing pattern, yellow, magenta, and cyan color inks were printed at 100% duty, and the black ink filled with the black ink of the present invention printed characters simultaneously. The ink discharge amount was 0.07 μg / dot, and the density was 360 dpi. Further, ink was filled in a BK cartridge of an inkjet printer BJC430 manufactured by Canon's Bubble Jet (registered trademark) system, and solids and characters were printed at a recording density of 360 dpi. After printing and drying, the blur at the boundary of the two-color overlapping portion, the image blur, the color tone, and the image density were comprehensively examined visually and by a reflective color spectrophotometric densitometer (manufactured by X-Rite), and judged according to the evaluation criteria. The printing test paper used is shown below.
(1) My paper (NBS Ricoh Co., Ltd.)
(2) Paper source S and recycled paper (manufactured by NBS Ricoh Co., Ltd.)
(3) PB paper (made by Canon Inc.)
(4) Multiace (Fuji Xerox Office Supply Co., Ltd.)
(5) Yamayuri paper (manufactured by Honshu Paper Co., Ltd., recycled paper)
(6) LH paper (Fuji Xerox Office Supply Co., Ltd.)
(7) Xerox 4024 paper (Fuji Xerox Office Supply Co., Ltd.)
(8) Neenah Bond paper (made by Kimberly Clark)
Judgment criteria A: Clear printing without occurrence of bleeding on all papers.
○: Whisker-like bleeding occurs on some paper (recycled paper).
Δ: Whisker-like bleeding occurs on all papers.
X: The blur has occurred so that the outline of the character is not clear.
2) Dryability of image The filter paper was pressed against the image after printing under certain conditions, and the time until the ink was not transferred to the filter paper was measured. When any paper was dried within 10 seconds, it was judged as “good”.
3) Storage stability Each ink is put in a polyethylene container and stored at −20 ° C., 5 ° C., 20 ° C., and 70 ° C. for 3 months, and after storage, surface tension, viscosity, and the presence or absence of precipitation. I investigated. Even if it preserve | saved on what conditions, the thing which does not change a physical property etc. was set as (circle).
4) Reliability when printing is stopped Using the head of the Ricoh printer IPSiO Jet300, it is investigated how much time (seconds) can be recovered after printing is stopped without capping, cleaning, etc. during printer operation. Table 1 shows the results of evaluating the reliability according to whether the ejection direction is deviated or the weight of the ejected droplet is changed.

Claims (1)

A pigment comprising at least a pigment, a water-soluble organic solvent, and water, wherein the pigment can be dispersed and / or dissolved in water without a dispersant in which a phenol compound is added to the pigment by a radical reaction; and A water-based pigment ink composition comprising a water-soluble cationic polymer or oligomer.