Ink composition for inkjet recording and colorant dispersion

Abstract

To provide an ink composition for ink jet recording and a coloring material dispersion liquid, which have excellent storage stability and can form a coating film having improved flexibility.SOLUTION: An ink composition for ink jet recording includes resin particles of a urethane resin colored with a disperse dye, and the acid value of the urethane resin is 1 KOHmg / g or more and less than 100 KOHmg / g.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to an ink composition for inkjet recording and a colorant dispersion liquid. [Background technology]

[0002] BACKGROUND ART Conventionally, printing onto polyester fabrics has been carried out by an inkjet method using inkjet inks containing sublimation dyes or disperse dyes having sublimation properties.

[0003] Such textile printing methods include a direct printing method in which ink is applied to a recording medium to be dyed and then the dye is fixed by heat treatment such as steaming, and a thermal transfer printing method in which dye ink is applied to an intermediate transfer medium and then the dye is sublimated and transferred from the intermediate transfer medium to the recording medium to be dyed by heat.

[0004] Patent Document 1 discloses a method for printing onto a recording medium such as a polyester fabric or a cotton fabric by an inkjet method using an inkjet recording ink containing a disperse dye in polyester fine particles, as a means for omitting the dyeing step and the transfer step among the dyeing steps described above. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 10-114865 [Patent Document 2] WO2016 / 027835 publication Summary of the Invention [Problem to be solved by the invention]

[0006] However, the ink described in Patent Document 1 has a problem with storage stability because the dye is dispersed using a dispersant. Furthermore, the recording methods described in Patent Documents 1 and 2 use only polyester resin particles, which tends to result in a coating film that lacks flexibility. Therefore, when a flexible recording medium is printed and then bent, the coating film is prone to cracking. In other words, there has been a demand for an inkjet recording ink composition and a colorant dispersion liquid that have excellent storage stability and improved coating film flexibility. [Means for solving the problem]

[0007] The ink composition for ink jet recording contains resin particles of a urethane resin colored with a disperse dye, and the acid value of the urethane resin is 1 KOHmg / g or more and less than 100 KOHmg / g.

[0008] The colorant dispersion liquid contains resin particles of a urethane resin colored with a disperse dye, and the acid value of the urethane resin is 1 KOHmg / g or more and less than 100 KOHmg / g. DETAILED DESCRIPTION OF THE INVENTION

[0009] 1.Color material dispersion liquid The colorant dispersion liquid according to this embodiment contains resin particles of a urethane resin colored with a disperse dye, water, and other components. The colorant dispersion liquid is formed by dispersing components such as resin particles in a medium such as water. The colorant dispersion liquid is used to produce an ink composition for inkjet recording, which will be described later. The inkjet recording ink can be used to record on multiple types of recording media, such as paper, as well as cotton and polyester fabrics, using an inkjet method. The various components contained in the colorant dispersion liquid are described below. In the following description, the inkjet recording ink composition will also be simply referred to as ink.

[0010] 1.1.Resin particles The resin particles contain a urethane resin and a disperse dye, and the resin particles are made of a urethane resin-based resin particle in which disperse dye molecules are dispersed.

[0011] The average particle size of the resin particles is preferably 30 nm or more, more preferably 40 nm or more, and even more preferably 50 nm or more, and is preferably 500 nm or less, more preferably 400 nm or less, and even more preferably 300 nm or less.

[0012] When the average particle size of the resin particles is within the above range, the resin particles are less likely to settle, thereby improving storage stability. This improves the density of the resin particles forming the coating film formed from the ink by the inkjet method. Hereinafter, the coating film formed from the ink composition for inkjet recording will also be simply referred to as the coating film.

[0013] In this specification, the average particle size refers to the particle size distribution based on scattered light intensity (50%). The average particle size is determined from the scattered light intensity distribution. For example, an ELSZ-1000 (manufactured by Otsuka Electronics Co., Ltd.) can be used to measure the average particle size.

[0014] 1.1.1.Urethane resin The urethane resin is an anionic resin having an acid value, and is obtained by polymerizing polyester polyol, isocyanate, and other polyols as raw materials.

[0015] Among these, polyester polyols are particularly preferred. By using polyester polyols, which are generally easily dyed with disperse dyes, the color development of the coating film is improved. Furthermore, the fixation when printing on polyester fabric or paper is improved, and the coating film is less likely to crack.

[0016] The acid value of the urethane resin is preferably 1 KOHmg / g or more, more preferably 3 KOHmg / g or more, and even more preferably 5 KOHmg / g or more, and is preferably less than 100 KOHmg / g, more preferably less than 80 KOHmg / g, and even more preferably less than 60 KOHmg / g.

[0017] When the acid value of the urethane resin is within the above range, resin particles having a narrow average particle size distribution can be obtained, thereby improving storage stability.

[0018] 1.1.1.1. Polyester polyol The polyester polyol is produced as a precursor of a urethane resin and is obtained by polymerizing the following polyol, dibasic acid, and tribasic acid as raw materials.

[0019] The polyol is a monomer component having two or more hydroxyl groups as functional groups. Examples of the polyol include ethylene glycol, diethylene glycol, triethylene glycol, neopentyl glycol, propylene glycol, dipropylene glycol, butanediol, polyethylene glycol, 1,3-propanediol, 1,4-butanediol, 3-methyl-1,5-pentanediol, 1,4-cyclohexanedimethanol, isosorbide, erythritan, bisphenol A, hydrogenated bisphenol A, and bisphenol A alkylene oxide adducts.

[0020] Of these, ethylene glycol, diethylene glycol, bisphenol A, 3-methyl-1,5-pentanediol, and neopentyl glycol are particularly preferred from the viewpoint of flexibility and color development of the coating film.

[0021] The polyols can be used singly or in combination of two or more.

[0022] Dibasic acids are monomeric components that have two functional carboxyl groups. Acid anhydrides and alkyl esters of dibasic acids with 1 to 4 carbon atoms can also be used.

[0023] Examples of dibasic acids include phthalic acid, isophthalic acid, terephthalic acid, fumaric acid, maleic acid, adipic acid, sebacic acid, succinic acid, cyclohexanedicarboxylic acid, and acid anhydrides thereof, as well as alkyl esters thereof having 1 to 4 carbon atoms.

[0024] Of these, dimethyl adipate, dimethyl terephthalate, and dimethyl isophthalate are particularly preferred from the viewpoint of flexibility and color development of the coating film.

[0025] The dibasic acids may be used alone or in combination of two or more.

[0026] Tribasic acids are monomeric components that have three functional carboxyl groups. Acid anhydrides and alkyl esters of these acids with 1 to 4 carbon atoms can also be used.

[0027] Examples of tribasic acids include trimellitic acid, trimesic acid, and acid anhydrides thereof.

[0028] Of these, trimellitic acid and trimesic acid are particularly preferred, as they can impart appropriate hydrophilicity to the urethane resin, thereby enabling the production of resin particles with a narrower average particle size distribution and contributing to improved storage stability.

[0029] The tribasic acids may be used alone or in combination of two or more.

[0030] The polyester polyol of the present embodiment can be obtained by copolymerizing a polyol, a dibasic acid, and a tribasic acid. The polymerization reaction is not particularly limited, but may be, for example, polycondensation or polyaddition.

[0031] 1.1.1.2. Isocyanates An isocyanate is a component that has one or more isocyanato groups, which are functional groups. Examples of the isocyanate include 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate, m-phenylene diisocyanate, p-phenylene diisocyanate, 3,3'-dimethyl-4,4'-biphenylene diisocyanate, 1,3-xylylene diisocyanate, 1,4-xylylene diisocyanate, 1,5-naphthalene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, 4-methyl-1,3-cyclohexylene diisocyanate, 1,2-bis(isocyanatomethyl)cyclohexane, 1,3-bis(isocyanatomethyl)cyclohexane, 1,4-bis(isocyanatomethyl)cyclohexane, and dicyclohexylmethane-4,4'-diisocyanate.

[0032] It is particularly preferred that the isocyanate has two or more isocyanato groups, which increases the proportion of urethane bonds in the urethane resin and improves the strength of the coating film.

[0033] Among the above isocyanates, it is particularly preferable to use one or more of hexamethylene diisocyanate, 1,3-bis(isocyanatomethyl)cyclohexane, dicyclohexylmethane-4,4'-diisocyanate, and isophorone diisocyanate, which increases the degree of freedom of molecular motion in the urethane resin, making the urethane resin more flexible and improving the flexibility of the coating film.

[0034] 1.1.1.3. Other polyols The other polyol is a component used together with the polyester polyol when synthesizing the urethane resin. Examples of the other polyol include polytetramethylene glycol and dimethylolpropionic acid. The other polyols are not limited to these, and the polyols listed above as raw materials for the polyester polyol can also be used.

[0035] Among these, dimethylolpropionic acid is particularly preferred as the other polyol, as it can impart appropriate hydrophilicity to the urethane resin, thereby enabling the production of resin particles with a narrower average particle size distribution, which contributes to improved storage stability.

[0036] 1.1.1.4. Urethane resin manufacturing method The urethane resin of this embodiment can be obtained by copolymerizing a polyester polyol, an isocyanate, and another polyol. The polymerization reaction is not particularly limited, but may be, for example, polyaddition.

[0037] 1.1.2. Disperse dye The ink and colorant dispersion of this embodiment contain resin particles based on urethane resin, and the resin particles contain a disperse dye.

[0038] The disperse dye may be contained in the resin particles of the urethane resin, but is preferably dispersed in the resin particles. Even if the resin particles contain the disperse dye in a dispersed state, a portion of the disperse dye may be exposed on the surface of the resin particles.

[0039] According to this, the use of a highly flexible urethane resin imparts flexibility to the coating film, which improves the conformability of the coating film when recording on a flexible recording medium, even when the recording medium is bent, resulting in less cracking of the coating film.

[0040] The mass of the urethane resin relative to the mass of the disperse dye in the resin particles is preferably 4 to 30 times. According to this, if the mass of the urethane resin is 4 or more times the mass of the disperse dye, excess disperse dye is reduced when the disperse dye is dispersed in the urethane resin, thereby improving the color development of the coating film, and if the mass of the urethane resin is 30 or less times the mass of the disperse dye, a sufficient amount of disperse dye is contained relative to the urethane resin, thereby improving the color development of the coating film.

[0041] Examples of disperse dyes include CI (Colour Index Generic Name) Disperse Yellow 1, 3, 4, 5, 7, 9, 13, 23, 24, 30, 33, 34, 42, 43, 44, 49, 50, 51, 54, 56, 58, 60, 61, 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, 149, 154, 160, 162, 163, 164, 165, 179, 180, and 182. 183, 184, 186, 192, 198, 199, 201, 202, 204, 210, 211, 215, 216, 218, 224, 227, 231, 232; CI 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, 12 7, 130, 139, 142; CI Disperse Red 1, 4, 5, 7, 11, 12, 13, 15, 17, 27, 43, 44, 50, 52, 53, 54, 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, 127, 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, 257, 258, 277, 278, 279, 281, 288, 298, 302, 303, 310, 311, 312, 320, 324, 328, 362, 364; CI Bat Red 41; CIDisperse 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; CI Disperse Green 9; CI Disperse Brown 1, 2, 4, 9, 13, 19; CI Disperse Blue 3, 7, 9, 14, 16, 19, 20, 24, 26, 27, 35, 43, 44, 54, 55, 56, 58, 60, 62, 64, 71, 72, 73, 75, 79, 81, 82, 83, 87, 91, 92, 93, 94, 95, 96, 102, 106, 108, 112, 113 , 115, 118, 120, 122, 125, 128, 130, 139, 141, 142, 143, 146, 148, 149, 153, 154, 158, 165, 167, 171, 173, 174, 176, 181, 183, 185, 186, 187, 189, 197, 198, 200, 201 1, 205, 207, 211, 214, 224, 225, 257, 259, 267, 268, 270, 284, 285, 287, 288, 291, 293, 295, 297, 301, 315, 330, 333, 359, 360; CI Disperse Black 1, 3, 10, 24, etc.

[0042] The disperse dyes may be used alone or in combination of two or more.

[0043] 1.2.Water The water functions as a dispersion medium for the resin particles. As the water, for example, pure water such as reverse osmosis (RO) water, distilled water, or ion-exchanged water may be used.

[0044] 1.3.Other Ingredients The colorant dispersion may contain other components in addition to those described above. Examples of other components include colorants other than disperse dyes, resin materials other than urethane resins, various dispersants, emulsifiers and surfactants, water-soluble organic solvents, penetrants, drying inhibitors, pH adjusters, chelating agents such as ethylenediaminetetraacetate, preservatives, antifungal agents, and rust inhibitors. Suitable preservatives and antifungal agents include compounds having an isothiazolinone ring structure in their molecules. The above-mentioned other components may not be included in the colorant dispersion, but may be added when preparing ink from the colorant dispersion.

[0045] 1.3.1. pH adjusters The pH adjuster is not particularly limited, but examples thereof include inorganic acids such as sulfuric acid, hydrochloric acid, and nitric acid, inorganic bases such as lithium hydroxide, sodium hydroxide, potassium hydroxide, and ammonia, organic acids such as adipic acid, citric acid, and succinic acid, and organic bases such as triethanolamine, diethanolamine, monoethanolamine, and tripropanolamine. The pH adjusters may be used alone or in combination of two or more.

[0046] Surfactants The surfactant is not particularly limited, but examples thereof include anionic surfactants, cationic surfactants, and nonionic surfactants.

[0047] Examples of anionic surfactants include higher fatty acid salts such as sodium laurate, sodium stearate, and sodium oleate; alkyl sulfate salts such as sodium dodecyl sulfate, sodium lauryl sulfate, cetyl sulfate, sodium stearyl sulfate, and sodium oleyl sulfate; higher alcohol sulfate salts such as sodium octyl alcohol sulfate, sodium lauryl alcohol sulfate, and ammonium lauryl alcohol sulfate; fatty alcohol sulfate salts such as sodium acetyl alcohol sulfate; alkyl benzene sulfonates such as sodium dodecyl benzene sulfonate, sodium lauryl benzene sulfonate, cetyl benzene sulfonate, sodium stearyl benzene sulfonate, and sodium oleyl benzene sulfonate; alkyl naphthalene sulfonates such as sodium isopropyl naphthalene sulfonate; and alkyl diphenyl ether disulfonates such as sodium alkyl diphenyl ether disulfonates. Examples of the alkyl phosphate ester salts include diphenyl ether disulfonates, sodium lauryl phosphate, and sodium stearyl phosphate; polyethylene oxide adducts of alkyl ether sulfates such as a polyethylene oxide adduct of sodium lauryl ether sulfate, a polyethylene oxide adduct of ammonium lauryl ether sulfate, and a polyethylene oxide adduct of triethanolamine lauryl ether sulfate; polyethylene oxide adducts of alkyl phenyl ether sulfates such as a polyethylene oxide adduct of sodium nonylphenyl ether sulfate; polyethylene oxide adducts of alkyl ether phosphates such as a polyethylene oxide adduct of sodium lauryl ether phosphate; polyethylene oxide adducts of alkyl phenyl ether phosphates such as a polyethylene oxide adduct of sodium nonylphenyl ether phosphate; perfluoroalkyl sulfonates, perfluoroalkyl carboxylates, and perfluoroalkyl phosphate esters.

[0048] Examples of cationic surfactants include quaternary ammonium salts such as lauryltrimethylammonium chloride, cetyltrimethylammonium chloride, cetyltrimethylammonium bromide, stearyltrimethylammonium chloride, behenyltrimethylammonium chloride, distearyldimethylammonium chloride, and lanolin-derived quaternary ammonium salts; pyridinium salts such as laurylpyridinium chloride, laurylpyridinium bromide, and cetylpyridinium chloride; imidazolinium salts such as 2-stearyl-hydroxyethyl-2-imidazoline derivatives; and amine salts such as N,N-diethyl-stearamido-methylamine hydrochloride and polyoxyethylenestearylamine.

[0049] Examples of nonionic surfactants include polyethylene glycol alkyl ethers such as polyethylene glycol cetyl ether, polyethylene glycol stearyl ether, polyethylene glycol oleyl ether, and polyethylene glycol behenyl ether; polyethylene glycol polypropylene glycol alkyl ethers such as polyethylene glycol polypropylene glycol cetyl ether and polyethylene glycol polypropylene glycol decyl tetradecyl ether; polyethylene glycol alkylphenyl ethers such as polyethylene glycol octylphenyl ether and polyethylene glycol nonylphenyl ether; polyethylene glycol fatty acid esters such as ethylene glycol monostearate, ethylene glycol distearate, diethylene glycol stearate, polyethylene glycol distearate, polyethylene glycol monolaurate, polyethylene glycol monostearate, and polyethylene glycol monooleate; glyceryl monomyristate, glyceryl monostearate, and monoisostearyl ether; Glycerin fatty acid esters such as glyceryl esterate, glyceryl distearate, and glyceryl dioleate; sorbitan fatty acid esters such as sorbitan monopalmitate, sorbitan monostearate, sorbitan tristearate, sorbitan monooleate, and sorbitan trioleate; polyethylene oxide adducts of glycerin fatty acid esters such as polyethylene oxide adduct of glyceryl monostearate and polyethylene oxide adduct of glyceryl monooleate; polyethylene oxide adducts of sorbitan fatty acid esters such as polyethylene oxide adduct of sorbitan monopalmitate, polyethylene oxide adduct of sorbitan monostearate, polyethylene oxide adduct of sorbitan tristearate, polyethylene oxide adduct of sorbitan monooleate, and polyethylene oxide adduct of sorbitan trioleate; polyethylene oxide adducts of sorbitan monolaurate, polyethylene oxide adduct of sorbitan tetrastearate, and polyethylene oxide adduct of sorbitan hexastearate;Examples include polyethylene oxide adducts of sorbitol fatty acid esters such as polyethylene oxide adduct of sorbitol tetraoleate, polyethylene oxide adducts of castor oil, alkylene oxide adducts of 2,4,7,9-tetramethyl-5-decyne-4,7-diol and 2,4,7,9-tetramethyl-5-decyne-4,7-diol, as well as alkylene oxide adducts of 2,4-dimethyl-5-decyne-4-ol and 2,4-dimethyl-5-decyne-4-ol, perfluoroalkylethylene oxide adducts, polysiloxane compounds, and polyether-modified organosiloxanes.

[0050] The surfactants may be used alone or in combination of two or more.

[0051] 1.3.3. Water-soluble organic solvents The water-soluble organic solvent is not particularly limited, and examples thereof include glycerin; glycols such as ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, 1,3-propanediol, 1,2-butanediol, 1,2-pentanediol, 1,2-hexanediol, 1,4-butanediol, 1,5-pentanediol, 3-methyl-1,5-pentanediol, and 1,6-hexanediol; ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, and propylene glycol monomethyl ether. Examples of the water-soluble organic solvent include glycol monoethers such as propylene glycol monoethyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, triethylene glycol monomethyl ether, and triethylene glycol monobutyl ether; nitrogen-containing solvents such as 2-pyrrolidone, N-methyl-2-pyrrolidone, and N-ethyl-2-pyrrolidone; and alcohols such as methanol, ethanol, n-propyl alcohol, isopropyl alcohol, n-butanol, 2-butanol, tert-butanol, iso-butanol, n-pentanol, 2-pentanol, 3-pentanol, and tert-pentanol. The water-soluble organic solvent may be used alone or in combination of two or more.

[0052] 1.3.4. Resin materials other than urethane resin The colorant dispersion liquid may further contain a resin other than the urethane resin. The other resin is not particularly limited, but examples thereof include anionic resins, cationic resins, and nonionic resins. By including such a resin, the resin particles can be fixed to the recording medium.

[0053] The cationic resin is not particularly limited, but examples thereof include starch derivatives such as cationic starch, cationic urethane resins, cationic olefin resins, and cationic allylamine resins.

[0054] Examples of anionic resins include cellulose derivatives such as carboxymethyl cellulose salts and viscose, and natural resins such as alginates, gum arabic, gum tragacanth, and lignin sulfonates.

[0055] The nonionic resin is not particularly limited, but examples thereof include acrylic resin, styrene-acrylic resin, urethane resin, ester resin, olefin resin, and vinyl acetate resin.

[0056] 1.4.Method for producing colorant dispersion liquid The method for producing a colorant dispersion liquid includes an emulsified suspension preparation step of mixing a first composition containing a disperse dye, a urethane resin, and an organic solvent with a second composition containing water to prepare an emulsified suspension, and an organic solvent removal step of removing at least a portion of the organic solvent from the emulsified suspension. Furthermore, other components may be mixed with the second composition or may be mixed after the organic solvent removal step.

[0057] First, a first composition containing a disperse dye, a urethane resin, and an organic solvent is prepared. The first composition may be prepared by simultaneously mixing the components, or by mixing the components in two or more separate stages.

[0058] For example, after preparing a kneaded mixture of a urethane resin and a disperse dye, the kneaded mixture may be mixed with an organic solvent to dissolve or disperse the urethane resin and the disperse dye.

[0059] As the organic solvent, for example, one having a solubility in water at 25° C. of 0.1 g / 100 g H2O or more and 30 g / 100 g H2O or less can be suitably used.

[0060] Examples of such organic solvents include ketones such as methyl ethyl ketone and methyl isopropyl ketone; and esters such as ethyl acetate, butyl acetate, and isopropyl acetate. One or more selected from these can be used in combination.

[0061] The organic solvent is preferably one that dissolves or disperses the urethane resin and is easy to remove in a subsequent step, and therefore, an organic solvent with a relatively low boiling point is preferred.

[0062] From this viewpoint, the organic solvent is preferably methyl ethyl ketone or ethyl acetate, and more preferably methyl ethyl ketone.

[0063] 1.4.1. Emulsion suspension preparation process In the emulsion suspension preparation step, the first composition and the second composition containing water are mixed to prepare an emulsion suspension.

[0064] The emulsified suspension thus obtained is in a state in which a dispersoid containing a disperse dye, a urethane resin, and an organic solvent is dispersed in an aqueous dispersion medium.

[0065] The second composition may be any composition containing at least water, for example, pure water or a liquid containing components other than water.

[0066] The components other than water contained in the second composition include, for example, basic components among the pH adjusters. When the second composition contains a basic component, the carboxyl groups of the urethane resin can be neutralized, thereby improving the hydrophilicity of the urethane resin.

[0067] The basic component may be mixed with the first composition prior to mixing the first and second compositions, and the same effects as those described above can be obtained in this case as well.

[0068] This makes it possible to more suitably hydrophilize the urethane resin, and to make the particle size distribution of the resin particles finally obtained narrower.

[0069] As the basic component, for example, one or a combination of two or more selected from inorganic bases and organic bases can be used.

[0070] The first composition and the second composition may be mixed by, for example, supplying the second composition to the first composition, or by supplying the first composition to the second composition, but it is preferable to mix the second composition by dropping it into the first composition, which more effectively produces an emulsified suspension.

[0071] Furthermore, the first composition and the second composition are preferably mixed by supplying the second composition to the first composition while stirring the first composition, which makes it possible to more suitably obtain an emulsified suspension.

[0072] 1.4.2. Organic solvent removal process In the organic solvent removal step, at least a portion of the organic solvent is removed from the emulsified suspension, thereby forming solid particles containing a disperse dye and a urethane resin, which correspond to the resin particles constituting the colorant dispersion liquid.

[0073] The organic solvent removal step is carried out, for example, by heating the emulsified suspension or placing the emulsified suspension in a reduced pressure environment.

[0074] The colorant dispersion liquid obtained in the organic solvent removal step, in which solid resin particles containing a disperse dye and a urethane resin are dispersed in an aqueous dispersion medium, may be used as the ink of this embodiment as is, or the colorant dispersion liquid may be mixed with other components to form the ink of this embodiment.

[0075] After the organic solvent removal step, post-treatment steps such as washing and drying may be carried out, which allows unnecessary components to be removed and makes it possible to obtain an ink with a more reliably adjusted composition.

[0076] The resin particles contained in the colorant dispersion liquid obtained in the organic solvent removal step can be washed by, for example, separating the resin particles from the dispersion liquid constituting the colorant dispersion liquid using a separation means such as a centrifuge, a filter press, or a belt filter to obtain a microparticle cake, and then stirring and dispersing the microparticle cake in water, and further dehydrating the microparticle cake.

[0077] After dehydration, a drying treatment may be carried out as necessary using, for example, a mixing vacuum dryer such as a Ribocone dryer (manufactured by Okawahara Manufacturing Co., Ltd.) or a Nauta Mixer (manufactured by Hosokawa Micron Corporation), or a fluidized bed dryer such as a fluidized bed dryer (manufactured by Okawahara Manufacturing Co., Ltd.) or a vibration fluidized bed dryer (manufactured by Chuo Kakoki Co., Ltd.).

[0078] When the dehydration treatment and drying treatment are performed, the washed resin particles are mixed with other components containing at least water, thereby obtaining the colorant dispersion liquid of the present embodiment described above.

[0079] In the organic solvent removal step, it is sufficient to remove at least a portion of the organic solvent contained in the emulsified suspension, particularly the organic solvent contained in the dispersoids of the emulsified suspension, and complete removal is not necessary. Even in such cases, the remaining organic solvent can usually be sufficiently removed by post-treatment steps such as washing and drying. Furthermore, a small amount of organic solvent may remain in the finally prepared ink.

[0080] 2. Ink composition for inkjet recording The ink composition for ink jet recording according to this embodiment contains the colorant dispersion liquid described above, water, and other components.

[0081] The content of resin particles in the ink is preferably 10% by mass or more and 20% by mass or less relative to the total mass of the ink.

[0082] Since the content of resin particles in the ink is 10% by mass or more, a coating film is formed during printing, improving fixation to the recording medium.Since the content of resin particles in the ink is 20% by mass or less, the coating film structure is regular, allowing the strength of the coating film to be maintained.

[0083] 2.1.Water The ink may further contain water. The water is not particularly limited, but examples of the water include those exemplified in the colorant dispersion liquid.

[0084] 2.2.Other ingredients The ink may further contain other components, which are not particularly limited, but may include those exemplified in the colorant dispersion liquid.

[0085] 2.2.1. pH adjusters The ink may further contain a pH adjuster. The pH adjuster is not particularly limited, but examples thereof include those exemplified in the colorant dispersion. The pH adjuster in the ink may be a pH adjuster that is originally mixed into the colorant dispersion, or may be a pH adjuster that is added separately during ink preparation.

[0086] 2.2.2.Surfactants The ink may further contain a surfactant. The surfactant is not particularly limited, but examples thereof include those exemplified in the colorant dispersion liquid. The surfactant in the ink may be one that is originally mixed into the colorant dispersion liquid, or may be one that is added separately when preparing the ink.

[0087] 2.2.3. Water-soluble organic solvents The ink may further contain a water-soluble organic solvent. The water-soluble organic solvent is not particularly limited, but examples thereof include those exemplified in the colorant dispersion liquid. The water-soluble organic solvent in the ink may be one that is originally mixed with the colorant dispersion liquid, or may be one that is added separately during preparation of the ink.

[0088] As the water-soluble organic solvent, in order to more stably eject ink droplets by the inkjet method, glycerin, glycols and glycol monoethers are preferred, and diethylene glycol, propylene glycol, triethylene glycol monobutyl ether and glycerin are particularly preferred.

[0089] 2.3. Method for producing ink composition for inkjet recording The ink composition for ink jet recording is produced by mixing the above-mentioned components and stirring the mixture thoroughly to uniformly mix the components. After stirring, filtration may be carried out as necessary.

[0090] 3. Inkjet recording device An inkjet recording apparatus is an apparatus that ejects ink and applies it to a recording medium. Ink ejection by the inkjet method can be performed using a known inkjet recording apparatus such as an inkjet printer. As an ejection mechanism, a piezo method or a method in which ink is ejected by bubbles generated by heating the ink can be used. Among these, the piezo method is preferred from the viewpoint of preventing deterioration of the ink composition for inkjet recording.

[0091] 4. Recording Media The recording medium is appropriately selected depending on the purpose of the printed matter produced from the ink and the recording medium. Materials for forming the recording medium are not particularly limited, but examples include polyesters such as polyvinyl chloride (PVC), polypropylene, polyethylene, polycarbonate, cellulose diacetate, cellulose triacetate, cellulose propionate, cellulose butyrate, cellulose acetate butyrate, cellulose nitrate, and polyethylene terephthalate; resin materials such as polyethylene, polystyrene, polypropylene, polycarbonate, polyvinyl acetal, polyamide, urethane resin, and acrylic resin; and surface-treated materials thereof; glass, paper, metal, ceramics, leather, wood, pottery; fibers composed of at least one of these; various natural fibers such as silk, wool, cotton, linen, polyester, polyamide, acrylic, polyurethane, cellulose, linter, rayon, cupra, and acetate; synthetic fibers; and semi-synthetic fibers. One or more materials selected from these may be used in combination.

[0092] The recording medium may be in the form of, for example, a roll or a single sheet, a board, or a cloth, and may also be in the form of a three-dimensional object such as a sphere or a rectangular parallelepiped.

[0093] 5. Recording method The recording method involves ejecting ink using an inkjet recording apparatus and applying the ink to a recording medium. In this case, multiple types of ink compositions for inkjet recording may be used in combination, or an ink other than the ink composition for inkjet recording may be used in combination.

[0094] According to this embodiment, the following effects can be obtained.

[0095] The storage stability of the ink can be improved, and the flexibility of the coating film can be improved. That is, it is possible to provide an ink that has excellent storage stability and improves the flexibility of the coating film.

[0096] 6. Examples and Comparative Examples The effects of the present invention will be explained in more detail below with reference to examples and comparative examples, but the present invention is not limited to the following examples.

[0097] Tables 1 to 4 show the compositions of Examples 1 to 12 and Comparative Examples 1 and 2. Specifically, Table 1 shows the compositions of polyester polyols PE1 to PE6 and PEA used in the urethane resin. Table 2 shows the compositions and acid values of urethane resins Resin 1 to Resin 9 and Resin B. Table 3 shows the compositions of colorant dispersions 1 to 10, which contain Resin 1 to Resin 9, Resin B, and polyester polyol PEA as urethane resins, and colorant dispersions A and B. Table 4 shows the compositions of inks of Examples 1 to 12 and Comparative Examples 1 and 2, which contain colorant dispersions Dispersion 1 to Dispersion 10, and Dispersion A and B. In Tables 1 and 2, columns with no numerical values or "-" indicate that the component is not included. Tables 1 to 4 use abbreviations for some components. Each abbreviation is noted in the table.

[0098] 6.1. Synthesis of polyester polyol 6.1.1. Synthesis of Copolymer PE1 A 300 mL separable flask equipped with a stirrer was charged with 35 parts by weight of dimethyl adipate, 35 parts by weight of dimethyl terephthalate, 15 parts by weight of trimellitic acid, 17 parts by weight of ethylene glycol, 33 parts by weight of 3-methyl-1,5-pentanediol, and 4.6 parts by weight of tetrabutoxytitanium, and heated at 180°C for 3 hours under a nitrogen atmosphere. After that, the temperature was gradually increased to 220°C under reduced pressure while removing volatile components, and the mixture was heated for a total of 5 hours to obtain copolymer PE1.

[0099] 6.1.2. Synthesis of copolymers PE2-6 and PEA Copolymers PE2 to PE6 and PEA were synthesized in the same manner as for copolymer PE1, except that the types and amounts of the monomers used were changed so as to obtain the polyester polyols shown in Table 1. In Table 1, the amount of each component is expressed in parts by weight.

[0100] [Table 1]

[0101] AA: Dimethyl adipate TPA: Dimethyl terephthalate IPA: Dimethyl isophthalate TMA: Trimellitic acid BTC: Trimesic acid EG: Ethylene glycol DEG: Diethylene glycol BisA: Bisphenol A MPD: 3-methyl-1,5-pentanediol NPG: Neopentyl glycol

[0102] 6.2.Synthesis of urethane resin 6.2.1. Synthesis of Resin 1 100 parts by weight of PE1 was added to a 500 mL separable flask equipped with a stirrer and a dropping funnel, and 15 parts by weight of tolylene diisocyanate was added dropwise while heating to 80°C under a nitrogen atmosphere. The mixture was then heated at 120°C for 5 hours, and the reaction was terminated when the disappearance of the isocyanate-derived absorption was confirmed by FT-IR (Fourier Transform Infrared Spectroscopy). This yielded Resin 1. The acid value of Resin 1 was measured using the acid value measurement method described below and was found to be 18 KOHmg / g.

[0103] 6.2.2. Synthesis of Resins 2 to 9 and Resin B Resins 2 to 9 and Resin B were synthesized in the same manner as Resin 1, except that the types and amounts of monomers used were changed so as to obtain the urethane resins shown in Table 2 below. In Table 2, the blending amount of each component is expressed in parts by weight.

[0104] [Table 2]

[0105] PTMG: Polytetramethylene glycol 1000 DMPA: Dimethylolpropionic acid TDI: Tolylene diisocyanate HDI: Hexamethylene diisocyanate HXDI: 1,3-bis(isocyanatomethyl)cyclohexane IPDI: Isophorone diisocyanate HMDI: Dicyclohexylmethane-4,4'-diisocyanate

[0106] 6.2.3. Acid number measurement The acid value can be measured by dropping ethanolic potassium hydroxide into a solution of the obtained resin in tetrahydrofuran and determining the mass of potassium hydroxide required for neutralization relative to the mass of the resin used. For example, a GT-200 (manufactured by Nitto Seiko Analytech Co., Ltd.) can be used to measure the acid value.

[0107] 6.3. Preparation of colorant dispersion 6.3.1. Preparation of Dispersion 1 50 parts by weight of Resin 1, 50 parts by weight of ethyl acetate, 1 part by weight of Disperse Red 60, and 2.4 parts by weight of triethanolamine were added to a 500 mL separable flask equipped with a stirrer and stirred. 100 parts by mass of pure water was added and mixed, and then the ethyl acetate was distilled off under reduced pressure to obtain Dispersion 1.

[0108] 6.3.2. Preparation of Dispersion 2 50 parts by weight of Resin 1, 50 parts by weight of methyl ethyl ketone, 1 part by weight of Disperse Red 60, and 2.4 parts by weight of triethanolamine were added to a 500 mL separable flask equipped with a stirrer and stirred. 100 parts by mass of pure water was added and mixed, and then the methyl ethyl ketone was distilled off under reduced pressure to obtain Dispersion Liquid 2.

[0109] 6.3.3. Preparation of Dispersions 3 to 10, A, and B Dispersions 3 to 10, A, and B were prepared in the same manner as Dispersion 2, except that the type and amount of resin used, and the amount of solvent and disperse dye were changed so as to obtain the dispersions shown in Table 3. In Table 3, the amount of each component used is expressed in parts by mass.

[0110] [Table 3]

[0111] MEK: Methyl ethyl ketone TEA: Triethanolamine DR60: CI Disperse Red 60

[0112] 6.3.4. Measurement of solids concentration The solid content concentration can be measured by weighing out, for example, 1 g of the colorant dispersion liquid and ink, and measuring the ratio of the weight remaining after freeze-drying to the weight before freeze-drying.

[0113] 6.4. Preparation of ink composition for inkjet recording Inks of Examples 1 to 12 and Comparative Examples 1 and 2 were prepared according to Table 4. In the ink composition column of Table 4, the amount of each component used is in mass %.

[0114] [Table 4]

[0115] BYK-348: Silicone surfactant, manufactured by BYK-Chemie E1010: Olfine E1010 acetylene glycol surfactant, manufactured by Nissin Chemical Industry Co., Ltd. PG: Propylene glycol BTG: Triethylene glycol monobutyl ether GL: Glycerin DEG: Diethylene glycol

[0116] Here, Example 1 is an ink prepared using Dispersion Liquid 1, and Dispersion Liquid 1 uses Resin 1, which in turn uses PE1.

[0117] Example 2 uses dispersion 2. Dispersion 2 uses resin 1, and resin 1 uses PE1. Dispersion 2 has a smaller particle size than dispersion 1.

[0118] Example 3 uses Dispersion 3. Dispersion 3 uses Resin 2, which in turn uses PE2. Resin 2 and subsequent resins represent levels in which one of hexamethylene diisocyanate, 1,3-bis(isocyanatomethyl)cyclohexane, dicyclohexylmethane-4,4'-diisocyanate, and isophorone diisocyanate is used.

[0119] Example 4 uses Dispersion Liquid 4. Dispersion Liquid 4 uses Resin 3, and Resin 3 uses PE3.

[0120] Example 5 uses dispersion 3. Dispersion 3 uses resin 2, and resin 2 uses PE2. The following examples are levels using dimethylolpropionic acid.

[0121] Example 6 uses Dispersion Liquid 2. Dispersion Liquid 2 uses Resin 1, and Resin 1 uses PE1.

[0122] Example 7 uses Dispersion Liquid 5. Dispersion Liquid 5 uses Resin 4, and Resin 4 uses PE6.

[0123] Example 8 uses Dispersion Liquid 6. Dispersion Liquid 6 uses Resin 5, and Resin 5 uses PE5.

[0124] Example 9 uses Dispersion 7. Dispersion 7 uses Resin 6, and Resin 6 uses PE3.

[0125] Example 10 uses dispersion 8. Dispersion 8 uses resin 7, and resin 7 uses PE4.

[0126] Example 11 uses dispersion 9. Dispersion 9 uses resin 8, and resin 8 uses PE5.

[0127] Example 12 uses dispersion 10. Dispersion 10 uses resin 9, and resin 9 uses PE2.

[0128] Comparative Example 1 uses dispersion A. Dispersion A uses polyester polyol PEA. Comparative Example 1 is a level in which polyester polyol is used as is and not converted into a urethane resin.

[0129] Comparative Example 2 uses Dispersion B. Dispersion B uses Resin B, which in turn uses PE3. Comparative Example 2 is a standard in which Resin B, which has a high acid value of 128 KOH mg / g, is used.

[0130] Evaluation The inks of the examples and comparative examples were evaluated as described below, and the evaluation results are shown in Table 5.

[0131] Storage Stability 5 g of each ink from each example and comparative example was placed in a 9 mL sample bottle and left at 60°C for 120 hours. The number of coarse particles was then measured using an FPIA-3000 (Malvern Panalytical) based on the number of restricted particles of 0.5 μm or larger. Evaluation was based on the following criteria: The lower the number of restricted particles, the better the storage stability. A: The number of limited particles is less than 100,000. B: The number of limited particles is 100,000 or more and less than 200,000 C: The number of limited particles is 200,000 or more.

[0132] 6.5.2.Flexibility The inks of each example and comparative example were ejected in a predetermined pattern onto MCPW paper (manufactured by Toppan Forms Co., Ltd.) as a recording medium using a recording device M105 (manufactured by Seiko Epson Corporation). The coating film, which was the colored portion of the resulting recording medium, was then gently folded at a 45-degree angle, and a pressure roller was rolled back and forth at a constant speed to create a crease. The crease in the recording medium was unfolded, and the crease was removed by rolling a clean cotton ball back and forth. The crease on the colored portion was then observed and evaluated according to the following criteria. The fewer lines caused by ink falling off the crease at the crease, the better the flexibility of the coating film. A: No lines caused by ink falling off can be seen. B: Some lines caused by ink loss can be seen. C: A continuous line caused by ink loss can be seen.

[0133] 6.5.3.Color development The inks of each example and comparative example were ejected in a predetermined pattern onto MCPW paper (manufactured by Toppan Forms Co., Ltd.) as a recording medium using a recording device M105 (manufactured by Seiko Epson Corporation). The optical density (OD) value of the ink-applied portion of the resulting print was then measured using an i1 (manufactured by X-rite Corporation) and evaluated according to the following criteria. The higher the OD value, the better the color development. A: The OD value is 1.2 or higher. B: The OD value is 1.0 or more and less than 1.2. C:OD value is 0.7 or more and less than 1.0. D: OD value is 0.5 or more and less than 0.7. E:OD value is less than 0.5.

[0134] 6.5.4. Fixability The inks of each example and comparative example were ejected in a predetermined pattern onto a cotton fabric recording medium using a recording device PX-M860F (Seiko Epson Corporation). The printed matter was washed in warm water at 40°C using laundry detergent (Top Clear Liquid, Lion Corporation) in the standard mode of a domestic washing machine (Toshiba Lifestyle Corporation, drum-type washer-dryer TW-Z9500L). The decrease in OD value of the dyed area before and after washing was determined and evaluated according to the following criteria. The lower the decrease in OD value, the better the fixation of the ink dyed to the recording medium. A: The decrease in OD value is less than 3%. B: The decrease in OD value is 3% or more but less than 10%. C: The decrease in OD value is 10% or more but less than 30%. D: The decrease in OD value is 30% or more but less than 50%. The decrease in E:OD value is 50% or more.

[0135] [Table 5]

[0136] 6.5.5. Summary of evaluation results As shown in Table 5, in terms of storage stability of the inks of the examples, Examples 1, 2, 3, and 4 were rated B. In particular, Examples 5, 6, 7, 8, 9, 11, and 12 were rated A. In terms of flexibility of the coating film of the inks of the examples, Examples 1 and 2 were rated B, and Examples 3 to 12 were rated A. This demonstrates that the inks of the examples have excellent storage stability and flexibility.

[0137] The color development of the inks of the examples was rated C for Examples 3, 4, and 5, and A for Examples 9, 10, 11, and 12. Furthermore, the fixability of the inks of the examples was rated B for Examples 7, 8, and 10, and A for Examples 9, 11, and 12. These results demonstrate that the color development and fixability of the inks of the examples are easy to improve.

[0138] On the other hand, the inks of the comparative examples were both rated C for storage stability and C for flexibility, demonstrating that it is difficult to improve storage stability and flexibility.

Claims

1. It contains resin particles of urethane resin colored with disperse dyes, The acid value of the urethane resin is 1 KOHmg / g or more and less than 100 KOHmg / g, The urethane resin contains polyester polyol and isocyanate as raw materials. fruit, The polyester polyol may be one or more of trimellitic acid and trimesic acid. An ink composition for ink jet recording, comprising the above as a raw material.

2. The isocyanate has two or more isocyanato groups as polymerizable functional groups. Item 2. The ink composition for ink jet recording according to item 1.

3. The isocyanate may be hexamethylene diisocyanate, 1,3-bis(isocyanate), (trimethyl)cyclohexane, dicyclohexylmethane-4,4'-diisocyanate, and and isophorone diisocyanate. Ink composition for ink jet recording.

4. The polyester polyol may be one or more of trimellitic acid and trimesic acid. The inkjet recording method according to any one of claims 1 to 3, comprising the above as a raw material. Ink composition.

5. The urethane resin further contains a polyol as a raw material, 5. The method according to claim 1, wherein the polyol contains dimethylolpropionic acid.

1. The ink composition for ink jet recording according to claim 1.

6. The resin particles have an average particle diameter of 30 nm or more and 500 nm or less. Item 6. The ink composition for ink jet recording according to any one of items 5 to 6.

7. 3. The content of the resin particles is 10% by mass or more and 20% by mass or less with respect to the total mass. Item 7. The ink composition for ink jet recording according to any one of items 1 to 6.

8. 4. The method of claim 1, wherein the mass of the urethane resin is 4 times or more and 30 times or less than the mass of the disperse dye. The ink composition for ink jet recording according to any one of claims 1 to 7.

9. It contains resin particles of urethane resin colored with disperse dyes, The acid value of the urethane resin is 1 KOHmg / g or more and less than 100 KOHmg / g, The urethane resin contains polyester polyol and isocyanate as raw materials. fruit, The polyester polyol may be one or more of trimellitic acid and trimesic acid. A colorant dispersion containing the above as a raw material.

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