JP2005264021A - Ink for inkjet and inkjet recording method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ink for inkjet, exhibiting excellent storage stability of the ink in a long-term preservation even if a disperse dye having a hydrolyzable substituent is used, and providing excellent stability of the obtained image; and to provide an inkjet recording method. <P>SOLUTION: The ink for the inkjet contains at least the disperse dye, a dispersant, water and a water-soluble solvent. The main disperse dye has a chemical structure of a carbonic acid ester or a carboxylic acid ester in the molecule, and the pH of the ink is ≥5.0 and <8.0 in the ink for the inkjet. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a novel inkjet ink and inkjet recording method for inkjet printing.

  An ink jet image printing method is a method in which fine droplets of ink are ejected from an ink jet recording head and attached to a target recording medium for printing. The ink jet method is advantageous in that its mechanism is relatively simple, inexpensive, and can form a high-definition and high-quality image.

  Taking advantage of this ink jet system, development is also progressing on image printing on fabric, so-called ink jet textile printing. Unlike conventional textile printing, ink jet textile printing has the advantage that it is not necessary to prepare a plate and can quickly form an image with excellent gradation. Further, since only a necessary amount of ink is used as a formed image, it can be said that this is an excellent image forming method having environmental advantages such as less waste liquid compared to the conventional method.

  In ink jet textile printing, the types of dyes that can be used are limited by the types of fibers constituting the fabric, and disperse dyes are generally used for dyeing fibers such as polyester.

  When disperse dyes are used for ink jet printing inks, in addition to the performance of color tone and fastness, which are the criteria for conventional dye selection for ink jet printing, the ink jet recording method uses fine nozzles to discharge fine particles. It is necessary to satisfy requirements such as dispersibility for forming particles, prevention of nozzle clogging, and dispersion stability, and there are many restrictions on dye selection. In particular, an ink using a disperse dye as a colorant is a dispersion system in which fine particles of colorant are dispersed in an aqueous medium, so that coarse particles are likely to be generated as compared with a dissolved ink that is a complete solution. In addition, performance such as clogging or sedimentation during storage over a long period of time due to generation of coarse particles due to aggregation during production or ink storage is required.

  Further, in the case of disperse dye ink, since it is dissolved in the ink unlike the pigment ink, ejection from the nozzle becomes poor due to Ostwald ripening or hydrolysis during long-term storage. In general, in the case of an aqueous dispersion ink, carboxylate, sulfonate, or the like is used as a dispersant used for dispersion, and the ink is kept alkaline. In particular, when the disperse dye has a hydrolyzable chemical structure such as a carbonate ester group or a carboxylic ester group, if the ink pH is kept alkaline or acidic, the disperse dye decomposes during long-term storage and has characteristics It was a challenge to change.

Examples of the dye having a carbonate group in the disperse dye of the ink jet ink include C.I. I. Disperse Red 302 and dyes having carboxylic acid esters include C.I. I. Disperse Yellow 149, C.I. I. Disperse Red 54, 127 and C.I. I. Disperse Blue 148 and the like, and examples in which these disperse dyes are applied to inkjet inks are disclosed (for example, see Patent Documents 1 and 2). However, it is a dye selection aiming at color developability and fastness, and is not aimed at improving the storage stability of the dye structure by paying attention to the dye structure.
JP-A-7-26476 JP 2000-239980 A

  The present invention has been made in view of the above problems, and the object thereof is excellent in the storage stability of the ink during long-term storage and the obtained image stability even when a disperse dye having a hydrolyzable substituent is used. Inkjet ink and inkjet recording method are provided.

  The above object of the present invention is achieved by the following configurations.

(Claim 1)
In an inkjet ink containing at least a disperse dye, a dispersant, water and a water-soluble organic solvent, the main disperse dye has a chemical structure of carbonate ester or carboxylate ester in the molecule, and the ink pH is 5.0 or more, 8 An ink-jet ink characterized by being less than 0.0.

(Claim 2)
The inkjet ink according to claim 1, wherein the main dispersant is lignin sulfonate.

(Claim 3)
The inkjet ink according to claim 1, wherein the water-soluble organic solvent is at least alkanediol and glycerin.

(Claim 4)
A disperse dye having a carbonic acid ester or a carboxylic acid ester chemical structure in the molecule is C.I. I. Disperse Red 302 or C.I. I. The inkjet ink according to any one of claims 1 to 3, wherein the ink is Disperse Yellow 149.

(Claim 5)
The amount of dissolved oxygen is 3.0 ppm or less, The ink for inkjets of any one of Claims 1-4 characterized by the above-mentioned.

(Claim 6)
6. An ink jet recording method for recording an image by ejecting the ink for ink jet according to claim 1 from a recording head, wherein the nozzle diameter of the recording head is 30 [mu] m or less. Recording method.

(Claim 7)
An inkjet recording method for recording an image by ejecting the inkjet ink according to any one of claims 1 to 5 from a recording head, wherein the recording head has a drive frequency of 20 kHz or more. Method.

  According to the present invention, there are provided an inkjet ink and an inkjet recording method which are excellent in storage stability of an ink during long-term storage and obtained image stability even when a disperse dye having a hydrolyzable substituent is used. Can do.

  Hereinafter, the best mode for carrying out the present invention will be described in detail.

  As a result of intensive studies, the present inventor has found that, in an inkjet ink containing at least a disperse dye, a dispersant, water, and a water-soluble organic solvent, the main disperse dye has a chemical structure of carbonate ester or carboxylate ester in the molecule. Ink-jet ink having an ink pH of 5.0 or more and less than 8.0 suppresses the formation of aggregates even when a disperse dye having a hydrolyzable substituent is used or stored for a long period of time. Ink jet ink and an ink jet recording method in which nozzle clogging at the time of emission is reduced and variation in the formed image is reduced can be realized.

  Details of the present invention will be described below.

  The disperse dye having a carbonic acid ester group or a carboxylic acid ester group that can be used in the present invention is not particularly limited as long as it has a carbonic acid ester group or a carboxylic acid ester group in the molecule. Various disperse dyes such as disperse dyes, anthraquinone disperse dyes, and quinophthalone disperse dyes can be used. Specific examples of the disperse dye include C.I. I. Disperse Yellow 149, C.I. I. Disperse Red 54, 127, 302 and C.I. I. Disperse Blue 148 and the like can be mentioned, but the present invention is not limited to these.

  In general, disperse dyes are nonionic dyes that do not have ionic water-soluble groups such as sulfonic acid and carboxy groups. They are finely powdered because of their low solubility in water, and are usually synthesized by dispersing in water using a dispersant. Used for fiber dyeing. Unlike pigments, it is soluble in organic solvents such as acetone and dimethylformamide. It is also known that it is possible to diffuse and color in the synthetic fiber in the form of molecules.

  When a disperse dye is used in an aqueous inkjet ink, the disperse dye is partially dissolved in the ink because the ink contains a water-soluble organic solvent, a surfactant, and the like. The solubility tends to increase as the disperse dye is made finer for inkjet. In the present invention, when a disperse dye containing a hydrolyzable chemical structure such as a carbonate ester group or a carboxylic ester group in the dye structure is used in an inkjet ink, the dissolved disperse dye is hydrolyzed. As a result, the hydrolyzed product precipitates in the ink, and this affects the emission stability and dispersion stability of the inkjet ink due to long-term storage. Even if the disperse dye used in the present invention has excellent characteristics in terms of color tone and fastness, it may satisfy the characteristics required for inkjet ink (for example, emission properties, ink storage stability, etc.). However, it is an important factor to suppress the solubility and hydrolyzability, and this can only be realized by adopting the ink configuration defined in the present invention.

  In the present invention, as described above, the main disperse dye has a chemical structure of carbonate ester or carboxylate ester in the molecule, but the main disperse dye in the present invention constitutes an ink jet ink. The disperse dye which occupies 50 mass% or more of the disperse dye to perform, Preferably it is 70 mass% or more, More preferably, it is 85 mass% or more, Most preferably, it is 95 mass% or more.

  Although the present invention relates to a disperse dye, other disperse dyes can be used in combination as necessary. In order to dye a fabric composed of a plurality of types of fibers by blending, union, etc., an acid dye, a direct dye It is also possible to mix and use color materials other than disperse dyes such as dyes.

  Specific compounds of preferred disperse dyes in the present invention are shown below. However, it is not limited to the compound illustrated to these.

[C. I. Disperse Yellow]
3, 4, 5, 7, 9, 13, 23, 24, 30, 33, 34, 42, 44, 49, 50, 51, 54, 56, 58, 60, 63, 64, 66, 68, 71, 74, 76, 79, 82, 83, 85, 86, 88, 90, 91, 93, 98, 99, 100, 104, 108, 114, 116, 118, 119, 122, 124, 126, 135, 140, 141, 160, 162, 163, 164, 165, 179, 180, 182, 183, 184, 186, 192, 198, 199, 202, 204, 210, 211, 215, 216, 218, 224, 227, 231, 232
[C. I. Disperse Orange]
1, 3, 5, 7, 11, 13, 17, 20, 21, 25, 29, 30, 31, 32, 33, 37, 38, 42, 43, 44, 45, 46, 47, 48, 49, 50, 53, 54, 55, 56, 57, 58, 59, 61, 66, 71, 73, 76, 78, 80, 89, 90, 91, 93, 96, 97, 119, 127, 130, 139, 142,
[C. I. Disperse Red]
1, 4, 5, 7, 11, 12, 13, 15, 17, 27, 43, 44, 50, 52, 53, 55, 56, 58, 59, 60, 65, 72, 73, 74, 75, 76, 78, 81, 82, 86, 88, 90, 91, 92, 93, 96, 103, 105, 106, 107, 108, 110, 111, 113, 117, 118, 121, 122, 126, 128, 131, 132, 134, 135, 137, 143, 145, 146, 151, 152, 153, 154, 157, 159, 164, 167, 169, 177, 179, 181, 183, 184, 185, 188, 189, 190, 191, 192, 200, 201, 202, 203, 205, 206, 207, 210, 221, 224, 225, 227, 229, 239, 240, 2 7,258,277,278,279,281,288,298,303,310,311,312,320,324,328,
[C. I. Disperse Violet]
1, 4, 8, 23, 26, 27, 28, 31, 33, 35, 36, 38, 40, 43, 46, 48, 50, 51, 52, 56, 57, 59, 61, 63, 69, 77,
[C. I. Disperse Green]
9,
[C. I. Disperse Brown]
1, 2, 4, 9, 13, 19
[C. I. Disperse Blue]
3, 7, 9, 14, 16, 19, 20, 26, 27, 35, 43, 44, 54, 55, 56, 58, 60, 62, 64, 71, 72, 73, 75, 79, 81, 82, 83, 87, 91, 93, 94, 95, 96, 102, 106, 108, 112, 113, 115, 118, 120, 122, 125, 128, 130, 139, 141, 142, 143, 146, 149, 153, 154, 158, 165, 167, 171, 173, 174, 176, 181, 183, 185, 186, 187, 189, 197, 198, 200, 201, 205, 207, 211, 214, 224, 225, 257, 259, 267, 268, 270, 284, 285, 287, 288, 291, 293, 295, 297, 301, 315, 330, 3 3,
[C. I. Disperse Black]
1, 3, 10, 24,
Etc.

  As content of a disperse dye, 0.1-20 mass% is preferable, and 0.2-13 mass% is more preferable. The disperse dye may be used as a commercial product, but it is preferable to carry out a purification treatment. As a purification method, a known recrystallization method, washing or the like can be used. The organic solvent used in the purification method and purification treatment is preferably selected as appropriate according to the type of dye.

  The particle size of the disperse dye is preferably 300 nm or less as the average particle size and 900 nm or less as the maximum particle size. This is because when the average particle size and the maximum particle size are large, clogging is likely to occur in the ink jet recording method in which light is emitted from a fine nozzle, and stable emission is not possible. The average particle diameter can be determined by a commercially available particle size measuring instrument using a light scattering method, an electrophoresis method, a laser Doppler method or the like. Specific examples of the particle diameter measuring apparatus include Zetar Sizer 1000 manufactured by Malvern.

  Dispersants preferably used in the present invention include, for example, a formalin condensate of sodium creosote oil sulfonate (eg, demole C), a formalin condensate of sodium cresol sulfonate and sodium 2-naphthol-6-sulfonate, and cresol sulfone. Formalin condensate of sodium sulfonate, formalin condensate of sodium phenol sulfonate, formalin condensate of sodium β-naphthol sulfonate, formalin condensate of sodium β-naphthalene sulfonate (eg, demole N) and sodium β-naphthol sulfonate , Lignin sulfonate (for example, Vanillex RN), sodium paraffin sulfonate (for example, Efcol 214), a copolymer of α-olefin and maleic anhydride (for example, Florene G-700), and the like. It is, but in the range of ink pH specified in the present invention, it is necessary to select the dispersibility and dispersion stability excellent dispersant, lignin sulfonate salt is particularly preferred.

  Examples of lignin sulfonates that can be used in the present invention include Vanillex RN (containing no sugar, manufactured by Nippon Paper Industries Co., Ltd.), Sun Extract 252 (containing sugars, manufactured by Nippon Paper Industries Co., Ltd.), and the like. This is a basic structure in which the α-position of the phenylpropane structure is sulfonated, and this unit extends in three dimensions. The molecular weight is preferably about 5,000 to 10,000, and the lignin sulfonate preferably does not contain saccharides.

  The main dispersant referred to in the present invention refers to a dispersant occupying 50% by mass or more of the dispersant constituting the inkjet ink, preferably 70% by mass or more, more preferably 85% by mass or more, and particularly preferably 95% by mass. % Or more.

  The amount of the dispersant used during dispersion is preferably 20 to 200% by mass with respect to the disperse dye. If the amount of the dispersant is small, desired micronization is not achieved, and the dispersion stability is lowered. Conversely, if the amount of the dispersant is excessive, the viscosity increases, which is not preferable from the viewpoint of the emission stability. These dispersants may be used alone or in combination of two or more.

  Depending on the structure of the disperse dye used, foaming or gelation may occur during dispersion, resulting in poor fluidity. In addition to the ability to form fine particles and dispersion stability, foaming during dispersion, gelation of the dispersion, It is necessary to select in consideration of the fluidity of the dispersion. An antifoaming agent may be added for the purpose of improving foaming during dispersion. In addition, the dispersant can affect the dyeability, dyeing rate, leveling property, transferability, color tone, fastness, etc. of the fabric, and tar of the dispersant or wetting agent when coloring at high temperatures. It is preferable to select in consideration of the fact that the dyeing becomes non-uniform due to the conversion.

  Since there is no dispersant that satisfies all of the above requirements, it is necessary to select an optimal dispersant according to the dye to be dispersed and add an antifoaming agent or the like as necessary. Further, a dispersant may be added during ink preparation. The dispersing agent at that time is preferably the same type as the dispersing agent used at the time of dispersion, but it may be used separately or in combination.

  Examples of the water-soluble organic solvent according to the present invention include polyhydric alcohols (for example, ethylene glycol, glycerin, 2-ethyl-2- (hydroxymethyl) -1,3-propanediol, tetraethylene glycol, triethylene glycol). , Tripropylene glycol, 1,2,4-butanetriol, diethylene glycol, propylene glycol, dipropylene glycol, butylene glycol, 1,6-hexanediol, 1,2-hexanediol, 1,5-pentanediol, 1,2 -Pentanediol, 2,2-dimethyl-1,3-propanediol, 2-methyl-2,4-pentanediol, 3-methyl-1,5-pentanediol, 3-methyl-1,3-butanediol, 2-methyl-1,3-propanediol, etc.), amino (Eg, ethanolamine, 2- (dimethylamino) ethanol, etc.), monohydric alcohols (eg, methanol, ethanol, butanol, etc.), polyhydric alcohol alkyl ethers (eg, diethylene glycol monomethyl ether, diethylene glycol monobutyl ether, Ethylene glycol monomethyl ether, triethylene glycol monobutyl ether, ethylene glycol monomethyl ether, ethylene glycol monobutyl ether, propylene glycol monomethyl ether, propylene glycol monobutyl ether, dipropylene glycol monomethyl ether, etc.), 2,2′-thiodiethanol, amides ( For example, N, N-dimethylformamide, etc.), heterocyclic rings (2-pyrrolidone, etc.), acetonitrile And the like. The amount of the water-soluble organic solvent is preferably 10 to 60% by mass with respect to the total ink mass.

  In addition to the above description, various additives for improving the performance can be used in the inkjet ink of the present invention. As the additive, for example, known antiseptics, antifungal agents, viscosity modifiers, surfactants, pH adjusters, metal chelators, antioxidants, ultraviolet absorbers and the like can be used.

  An inorganic salt may be added to the ink in order to improve the color development in order to keep the ink viscosity and dye stable. Examples of inorganic salts include sodium chloride, sodium sulfate, magnesium chloride, magnesium sulfide and the like. When implementing this invention, it is not limited to these.

  As the surfactant, any of cationic, anionic, amphoteric and nonionic can be used. Examples of the cationic surfactant include aliphatic amine salts, aliphatic quaternary ammonium salts, benzalkonium salts, benzethonium chloride, pyridinium salts, imidazolinium salts, and the like. Examples of anionic surfactants include fatty acid soap, N-acyl-N-methylglycine salt, N-acyl-N-methyl-β-alanine salt, N-acyl glutamate, alkyl ether carboxylate, acylated peptide , Alkyl sulfonate, alkyl benzene sulfonate, alkyl naphthalene sulfonate, dialkyl sulfosuccinate, alkyl sulfoacetate, α-olefin sulfonate, N-acylmethyl taurine, sulfated oil, higher alcohol sulfate Salts, secondary higher alcohol sulfates, alkyl ether sulfates, secondary higher alcohol ethoxy sulfates, polyoxyethylene alkylphenyl ether sulfates, monoglyculates, fatty acid alkylolamide sulfates, alkyl ether phosphates Salt, alkyl phosphate ester salt and the like. Examples of amphoteric surfactants include carboxybetaine type, sulfobetaine type, aminocarboxylate, imidazolinium betaine and the like. Nonionic surfactants include polyoxyethylene alkyl ether, polyoxyethylene secondary alcohol ether, polyoxyethylene alkylphenyl ether (eg, Emulgen 911), polyoxyethylene sterol ether, polyoxyethylene lanolin derivative, polyoxy Ethylene polyoxypropylene alkyl ether (for example, Newpol PE-62), polyoxyethylene glycerin fatty acid ester, polyoxyethylene castor oil, hydrogenated castor oil, polyoxyethylene sorbitan fatty acid ester, polyoxyethylene sorbitol fatty acid ester, polyethylene glycol fatty acid Esters, fatty acid monoglycerides, polyglycerol fatty acid esters, sorbitan fatty acid esters, propylene glycol fatty acid esters , Sucrose fatty acid esters, fatty acid alkanolamides, polyoxyethylene fatty acid amides, polyoxyethylene alkyl amines, alkyl amine oxides, acetylene glycol, acetylene alcohol, and the like. The present invention is not limited to these.

  When these surfactants are used, they can be used singly or as a mixture of two or more kinds. By adding 0.001 to 1.0% by mass with respect to the total amount of ink, the surface of the ink can be used. The tension can be arbitrarily adjusted, which is preferable.

  Examples of antiseptics and antifungal agents added to maintain the long-term storage stability of the ink include aromatic halogen compounds (for example, Preventol CMK), methylene dithiocyanate, halogen-containing nitrogen-sulfur compounds, and 1,2-benzisothiazoline-3. -On (for example, PROXEL GXL) and the like. The present invention is not limited to these.

  In the ink according to the present invention, in the case of a water-insoluble dye, it can be dispersed by mixing a dye, a dispersant, a wetting agent, a medium and an optional additive and using a disperser. As the disperser, a conventionally known ball mill, sand mill, line mill, high-pressure homogenizer, or the like can be used. The disperse dye is dispersed in an aqueous dispersion medium at a high concentration, and the obtained dispersion is diluted to about 1 to 10 times and further various types. It can be prepared by adding an additive to make an ink, degassing, and then filtering.

  Deaeration treatment is used to prevent the dissolved gas contained in the ink from being impaired in the resolution and clarity of the printed matter and causing fine bubbles in ink jet inks used in printers, etc. Do. Methods for degassing dissolved gas from the ink are roughly divided into a method of degassing by a physical method such as boiling or decompression, and a chemical method of mixing an absorbent into the ink. In the present invention, degassing can be performed by any means. In particular, the method of permeating and removing dissolved gas in the ink by passing the ink through the gas-permeable hollow fiber membrane and reducing the pressure on the outer surface side of the hollow fiber membrane has an adverse effect on the physical properties of the ink. This is preferable because the dissolved gas in the ink can be efficiently removed without giving.

  As the confirmation of the dissolved gas removal level, the dissolved oxygen concentration was measured at 25 ° C. and 1 atm using a commercially available dissolved oxygen concentration meter (DO-30A type manufactured by Toa Denpa Kogyo Co., Ltd.), and the dissolved oxygen concentration was measured. Is preferably 3 ppm or less, more preferably 0 to 2 ppm.

  The material constituting the fabric used in the inkjet recording method of the present invention is not particularly limited as long as it contains fibers that can be dyed with disperse dyes. Among them, fibers such as polyester, acetate, and triacetate are included. Those are preferred. Among them, a fabric containing at least polyester fibers is particularly preferable. As the fabric, the above-described fibers may be any form such as a woven fabric, a knitted fabric, and a non-woven fabric. Further, as the fabric that can be used in the present invention, it is preferable that the fiber that can be dyed with disperse dyes is 100%, but a mixed woven fabric with rayon, cotton, polyurethane, acrylic, nylon, wool, silk, etc. Alternatively, a blended nonwoven fabric or the like can also be used as a textile for printing. Further, the thickness of the yarn constituting the fabric as described above is preferably in the range of 10 to 100d.

  In the case of the ink jet recording method of the present invention, in order to obtain a uniform dyed product, natural impurities (oils, waxes, pectic substances, natural pigments, etc.) adhering to the fabric fiber before pretreatment of the fabric with water-soluble polymers ), It is desirable to wash away residues (such as glue) and dirt of the chemical used in the fabric manufacturing process. Examples of the cleaning agent used for cleaning include alkalis such as sodium hydroxide and sodium carbonate, surfactants such as anionic surfactants and nonionic surfactants, enzymes, and the like.

  In the inkjet recording method of the present invention, it is preferable to apply a pretreatment agent by a pad method, a coating method, a spray method or the like (pretreatment step) in order to prevent bleeding. Thereafter, an image is formed on the fabric containing fibers that can be dyed with a disperse dye by the ink jet recording method using the ink having the above-described configuration (ink application step), and then the ink is applied. The fabric is heat-treated (coloring step), and the heat-treated fabric is washed (washing step) to complete printing on the fabric and obtain a printed product.

  The pretreatment is not particularly limited as long as a method suitable for the fiber material and ink is appropriately selected from known methods such as pretreatment of water-soluble polymers on the fabric. For example, it is used for a fabric provided with 0.2 to 50% by mass of at least one substance selected from the group consisting of water-soluble metal salts, polycation compounds, water-soluble polymers, surfactants and water repellents. Therefore, it is possible to prevent a high degree of bleeding, and a high-definition image can be printed on a fabric.

  Specific water-soluble polymers used for the pretreatment include, for example, starches such as corn and wheat, cellulose derivatives such as carboxymethylcellulose, methylcellulose, and hydroxyethylcellulose, sodium alginate, and guar gum. Polysaccharides such as tamarind gum, locust bean gum and gum arabic, protein substances such as gelatin, casein and keratin, and synthetic water-soluble polymers include, for example, polyvinyl alcohol, polyvinyl pyrrolidone and acrylic acid polymers. it can.

  As the surfactant, for example, anionic, cationic, amphoteric, and nonionic surfactants are used. Typically, anionic surfactants include higher alcohol sulfates and sulfonates of naphthalene derivatives. Quaternary ammonium salt and the like as ionic surfactant; imidazoline derivative and the like as amphoteric surfactant; polyoxyethylene alkyl ether and polyoxyethylene propylene block polymer as nonionic surfactant Sorbitan fatty acid ester, polyoxyethylene sorbitan fatty acid ester, ethylene oxide adduct of acetylene alcohol, and the like.

  Examples of the water repellent include silicon, fluorine-based and wax-based ones. These water-soluble polymers and surfactants that are pre-applied to the fabric are stable against high-temperature environments because they do not cause dirt due to taring when ink-jet printing and color development at high temperatures. Preferably there is. Further, these water-soluble polymers and surfactants that are previously imparted to the fabric are preferably those that can be easily removed from the fabric by washing after ink jet printing and color development at high temperature.

  In the ink jet recording method for printing on a cloth, it is desirable to wind up the printed cloth after emitting the ink, develop a color by heating, and wash and dry the cloth. In ink jet textile printing, ink is not printed well just by printing it on a cloth and leaving it alone. In addition, when printing on a long fabric for a long time, the fabric comes out endlessly, and the printed fabric overlaps the floor etc., leaving a place that is unsafe and unexpectedly dirty. There is a case. Therefore, it is necessary to perform a winding operation after printing. During this operation, a medium not related to printing, such as paper, cloth, or vinyl, may be sandwiched between the cloths. However, it is not always necessary to wind up when cutting in the middle or short fabric.

  The color development step is a step of developing the original hue of ink by adhering to and fixing the dye in the ink that has only adhered to the fabric surface after printing and is not sufficiently adsorbed and fixed to the fabric. As the method, steaming by steam, baking by dry heat, thermosol, HT steamer by superheated steam, HP steamer by pressurized steam, etc. are used. They are appropriately selected depending on the material to be printed, ink, and the like. Further, the printed fabric may be immediately heat-treated or may be heat-treated after a while and may be dried and colored according to the intended use, and any method may be used in the present invention.

  When dyeing with a disperse dye, a carrier may be used in addition to a method of coloring at a high temperature. The compound used as the carrier is preferably a compound having characteristics such as large dyeing acceleration, simple use, stable, low burden on human body and environment, easy removal from the fiber, and no influence on dye fastness. Examples of carriers include o-phenylphenol, p-phenylphenol, methylnaphthalene, alkyl benzoate, alkyl salicylate, phenols such as chlorobenzene and diphenyl, ethers, organic acids, hydrocarbons and the like. These promote the swelling and plasticization of difficult-to-dye fibers that are difficult to dye at temperatures around 100 ° C. like polyester, and make it easier for disperse dyes to enter the fibers. The carrier may be preliminarily adsorbed on the fibers of the fabric used for inkjet printing, or may be included in the inkjet ink.

  In addition, a dyeing assistant can be added to the fabric. The dyeing assistant has the effect of forming a eutectic compound with water aggregated on the cloth when heating the printed cloth, reducing the amount of water that re-evaporates, and shortening the heating time. Further, this eutectic compound has a function of dissolving the dye on the fiber and promoting the diffusion rate of the dye into the fiber. Urea is mentioned as a dyeing assistant.

  The pretreatment agent is preferably selected according to the fabric material and fabric structure, and is preferably applied by a pad method, a coating method, a spray method or the like so as to contain 0.2 to 50% by mass in the fabric. In the ink jet recording method of the present invention, after forming an image by the ink jet recording method using the ink jet ink of the present invention on a fabric containing fibers that can be dyed with the above-described disperse dye (ink application) Step), the fabric to which the ink is applied is heat-treated (heat treatment step), and further, the fabric subjected to the heat treatment is washed (washing step), whereby the printing on the fabric is completed and a printed matter is obtained. In the ink jet recording method of the present invention, the disperse dye is fixed to the fiber by a method of heat-treating the fabric to which the ink is applied. Furthermore, as a method for removing unfixed dye from the fabric, a conventionally known cleaning method can be used, but it is particularly preferable to use a reduction cleaning.

  In the ink jet recording method for printing on a cloth, it is desirable to wind up the printed cloth after emitting the ink, develop a color by heating, and wash and dry the cloth. In ink jet textile printing, ink is printed on a fabric and simply left unattended, it does not dye well. In addition, when printing on a long fabric for a long time, the fabric comes out endlessly, and the printed fabric overlaps with the floor, etc., and it is unsafe and unexpectedly dirty. There is a case. Therefore, it is necessary to perform a winding operation after printing. During this operation, a medium not related to printing, such as paper, cloth, or vinyl, may be sandwiched between the cloths. However, it is not always necessary to wind up when cutting in the middle or short fabric.

  The printed fabric may be immediately heat-treated or may be heat-treated after a while, and may be dried and colored according to the intended use. As the heat treatment method, a method suitable for the application, such as an oven, a heat roll, or steam, may be selected.

  Cleaning is necessary after heat treatment. This is because a dye that has not participated in the dyeing remains, resulting in poor color stability and low fastness. It is also necessary to remove the pretreatment product applied to the fabric. If left as it is, the fabric is dyed as well as a decrease in fastness. Therefore, cleaning according to the object to be removed and the purpose is necessary.

Drying is required after washing. After the washed fabric is squeezed or dehydrated, it is dried or dried using a dryer, heat roll, iron or the like.
In addition, in the case of the inkjet printing method of the present invention, in order to obtain a uniform dyed product, natural impurities (oils, waxes, pectic substances, natural pigments, etc.) adhering to the fabric fibers before the ink receiving layer is pretreated on the fabric are obtained. ), It is desirable to wash away residues (such as glue) and dirt used in the fabric manufacturing process. As cleaning agents used for cleaning, alkalis such as sodium hydroxide and sodium carbonate, surfactants such as anionic surfactants and nonionic surfactants, enzymes and the like are used.

  By this series of actions, the characteristics as ink for inkjet printing are utilized, and a fabric on which a beautiful pattern is printed is completed.

  The recording head used in the inkjet recording method of the present invention is not particularly limited, and either a thermal type or a piezo type can be used.

  In the present invention, in order to obtain a high-definition image, recording is preferably performed using an inkjet head having a nozzle diameter of 30 μm or less. In order to improve the granularity, the smaller one is preferable, but since the droplet volume becomes too small and is influenced by the air flow, the range of 10 μm to 20 μm is particularly preferable.

  The drive frequency of the ink jet head drive device is preferably 20 kHz or more, and more preferably 30 kHz or more and 100 kHz or less in order to prevent ink clogging. For the same reason, the ink discharge speed is preferably 6 m / s or more, more preferably 8 m / s or more and 50 m / s or less.

  In the ink jet recording method of the present invention, the droplet volume at the time of ink flight is preferably 5 pl or more from the viewpoint of being less susceptible to the influence of the air current in the vicinity of the recording head, and 150 pl or less from the viewpoint of graininess of the printed image. Is preferable, and more preferably 5 to 80 pl.

  EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited thereto.

<Preparation of dye dispersion>
The following compositions were dispersed using a sand grinder to prepare dye dispersions 1 to 4. Dispersion stopped when the average particle size reached 160 nm.

Disperse dye (dispersed dye species listed in Table 1) 25 parts Glycerin 20 parts Ion-exchanged water 40 parts Dispersant (dispersant species listed in Table 1) 15 parts << Preparation of ink >>
[Preparation of ink composition]
Add each additive listed in Table 1 to each dye dispersion prepared above, mix, filter and degas through a 3 μm membrane filter to obtain ink compositions A, B, C, D, and E. Prepared.

  In addition, the detail of each additive described with the abbreviation in Table 1 is as follows.

[Disperse dye]
DR302: C.I. I. Disperse Red 302
DY149: C.I. I. Disperse Yellow 149
DB148: C.I. I. Disperse Blue 148
[Dispersant]
SA-1: Sodium lignin sulfonate (Vanilex RN, manufactured by Nippon Paper Industries Co., Ltd.)
SA-2: Formalin condensate of creosote oil sodium sulfonate (Demol C)
Manufactured by Kao)
(Water-soluble organic solvent)
EG: Ethylene glycol PG: Propylene glycol DEG: Diethylene glycol Gly: Glycerin [Surfactant]
* A: Sodium diethylhexyl sulfosuccinate [preservative]
P-GXL: Proxel GXL (S) (Avisia)
[Preparation of ink]
During the preparation of the ink composition, the pH is adjusted with hydrochloric acid or sodium hydroxide, and each ink composition is contained in a gas-permeable hollow fiber membrane (SEPAREL PF-004D manufactured by Dainippon Ink & Chemicals, Inc.). The ink was passed through and the outer surface side of the hollow fiber membrane was depressurized with a water aspirator to remove dissolved gas in the ink. At this time, after adjusting the deaeration level according to the liquid passing speed, vacuum packing was performed to prepare inks 1 to 23 having pH and dissolved oxygen concentration shown in Table 2.

  The pH and dissolved oxygen concentration of the ink were determined according to the following method.

(Measurement of pH)
Each ink was measured with a glass electrode pH meter manufactured by Toa Denpa.

(Measurement of dissolved oxygen concentration)
Each ink was measured at 25 ° C. and 1 atm using a dissolved oxygen concentration meter (DO-30A type manufactured by Toa Denpa Kogyo Co., Ltd.).

<Evaluation of ink>
(Evaluation of light emission)
(Evaluation 1)
For each of the inks prepared above, 500 ml of each ink was continuously ejected under an environment of 25 ° C. and 50% relative humidity using a piezo-type head having a nozzle diameter of 48 μm, a drive frequency of 10 kHz, and a nozzle number of 64, until the ink was exhausted. The generated bending and non-existence were measured, and the emissivity was evaluated according to the following evaluation criteria. The drive voltage was adjusted so that each ink volume was 60 pl.

◎: All nozzles emitted normally ○: Bending with 1 to 3 nozzles and missing shots △: Bending with 4 to 7 nozzles and missing shots ×: Bending with 8 to 12 nozzles and missing shots XX: Bends with 13 nozzles or more, and missing is observed.

(Evaluation 2)
For each of the inks prepared above, 500 ml of each ink was continuously ejected in an environment of 25 ° C. and 50% relative humidity using a piezo-type head having a nozzle diameter of 28 μm, a drive frequency of 20 kHz, and a nozzle number of 64. The generated bending and non-existence were measured, and the emissivity was evaluated according to the following evaluation criteria. The drive voltage was adjusted so that each ink volume was 20 pl.

◎: All nozzles emitted normally ○: Bending with 1 to 3 nozzles and missing shots △: Bending with 4 to 7 nozzles and missing shots ×: Bending with 8 to 12 nozzles and missing shots XX: Bends with 13 nozzles or more, and missing is observed.

(Evaluation 3)
After each ink was filled in the cartridge, a cycle of storing at 50 ° C. for 12 hours and at 0 ° C. for 12 hours was repeated for 4 weeks, and then the light emission property was evaluated by the same method as in Evaluation 2 above.

(Evaluation of printed materials)
Each ink was evaluated using a printer equipped with four piezo heads with a driving frequency of 20 kHz and a nozzle diameter of 30 μm, and a head unit with a resolution of 720 dpi × 720 dpi and a droplet speed adjusted to 6 m / s. The image was printed on pretreatment cloth A manufactured by Konica Minolta Technology Center.

  In addition, as an evaluation image, a 100% solid image obtained by landing all at 720 dpi × 720 dpi in a single color was used. In the present invention, dpi represents the number of dots per 2.54 cm.

<Evaluation of color difference 1>
After the ink was installed in the printer, the printed material was printed immediately, and the ink was loaded in the printer for 2 weeks, and then printed again by the above method to produce a printed material. Each printed matter was dried after standing for 12 hours at room temperature after printing, and was heated and colored at 195 ° C. for 20 minutes. After color development, after reducing and washing and drying naturally, using X-rite 938, L ^* , a ^* , b ^* are measured, and the color difference ΔE1 between the printed material just after loading and the printed material after 2 weeks from loading is calculated. Measured according to the following formula.

ΔE1 = [(ΔL ^* ) ² + (Δa ^* ) ² + (Δb ^* ) ² ] ^1/2
<Evaluation of color difference 2>
In the color difference evaluation 1, in place of the ink left in the printer for 2 weeks, it was filled in the cartridge prepared in the evaluation 3 of the light emission evaluation, and it was 12 hours at 0 ° C. and 12 hours at 50 ° C. The color difference ΔE2 between the printed materials obtained in the same manner was determined except that the ink in which the cycle of time storage was repeated for 4 weeks was used.

  The results obtained as described above are shown in Table 2.

  As apparent from the results shown in Table 2, the disperse dye has a chemical structure of carbonate ester or carboxylate ester in the molecule, and the ink of the present invention having an ink pH of 5.0 or more and less than 8.0 is As compared with the comparative example, it can be seen that even when stored for a long time or in a harsh state, the emission stability is good and the color variation of the printed matter produced using the same is small. Further, among these, it can be seen that the effect is more exhibited by setting the dissolved oxygen concentration of the ink to 3.0 ppm or less.

Claims (7)

In an inkjet ink containing at least a disperse dye, a dispersant, water and a water-soluble organic solvent, the main disperse dye has a chemical structure of carbonate ester or carboxylate ester in the molecule, and the ink pH is 5.0 or more, 8 An ink-jet ink characterized by being less than 0.0. The inkjet ink according to claim 1, wherein the main dispersant is lignin sulfonate. The inkjet ink according to claim 1, wherein the water-soluble organic solvent is at least alkanediol and glycerin. A disperse dye having a carbonic acid ester or a carboxylic acid ester chemical structure in the molecule is C.I. I. Disperse Red 302 or C.I. I. The inkjet ink according to any one of claims 1 to 3, wherein the ink is Disperse Yellow 149. The amount of dissolved oxygen is 3.0 ppm or less, The ink for inkjets of any one of Claims 1-4 characterized by the above-mentioned. 6. An ink jet recording method for recording an image by ejecting the ink for ink jet according to claim 1 from a recording head, wherein the nozzle diameter of the recording head is 30 [mu] m or less. Recording method. An inkjet recording method for recording an image by ejecting the inkjet ink according to any one of claims 1 to 5 from a recording head, wherein the recording head has a drive frequency of 20 kHz or more. Method.