Inkjet ink composition for dye printing

Abstract

To obtain an ink composition having excellent storage stability and discharge stability at a higher level.SOLUTION: An inkjet ink composition for dye printing according to the present invention contains a disperse dye, a dispersant, a water-soluble organic solvent, and a permeability-imparting solvent. The water-soluble organic solvent contains glycerol and propylene glycol. The permeability-imparting solvent contains one or more selected from the group consisting of 1,5-pentanediol, 1,2-butanediol, 3-methyl-1,5-pentanediol, and polyethylene glycol monomethyl ether.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an ink-jet ink composition for dye textile printing. [Background technology]

[0002] Inkjet recording methods have been attempted to be applied not only to recording images on media such as paper but also to textile printing on fabrics, and various ink compositions and recording methods for inkjet textile printing have been studied. For example, Patent Document 1 discloses an aqueous inkjet composition containing a dye composed of at least one of a sublimation dye and a disperse dye, polyester, 1-(hydroxyalkyl)-2-pyrrolidone, and water, in which the content of polyester is 4.0 to 300.0 times the content of the dye. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2021-155476 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the aqueous inkjet ink composition described in Patent Document 1 has the problem that it is not possible to obtain higher levels of storage stability and ejection stability. [Means for solving the problem]

[0005] The present invention provides an ink composition for dye textile printing, which comprises a disperse dye, a dispersant, a water-soluble organic solvent, a penetrability-imparting solvent, and water, wherein the water-soluble organic solvent comprises glycerin and propylene glycol, and the penetrability-imparting solvent comprises one or more solvents selected from the group consisting of 1,5-pentanediol, 1,2-butanediol, 3-methyl-1,5-pentanediol, and polyethylene glycol monomethyl ether. [Brief explanation of the drawings]

[0006] [Figure 1] 1 is a flowchart illustrating an example of an inkjet recording method. [Figure 2] Table 1 shows the composition of the ink composition for evaluating dye solubility. [Figure 3] Table 2 shows the compositions of inkjet ink compositions for dye textile printing. [Figure 4] Table 3 shows the compositions of inkjet ink compositions for dye textile printing. [Figure 5] Table 4 shows the compositions of inkjet ink compositions for dye textile printing. [Figure 6] Table 5 shows the evaluation results. [Figure 7] Table 6 shows the evaluation results. [Figure 8] Table 7 shows the evaluation results. DETAILED DESCRIPTION OF THE INVENTION

[0007] Below, an embodiment of the present invention (hereinafter referred to as "the present embodiment") will be described in detail, but the present invention is not limited to this and various modifications are possible within the scope of the gist thereof.

[0008] 1. Inkjet ink composition for dye printing The inkjet ink composition for dye textile printing (hereinafter also referred to as "ink composition") of this embodiment contains a disperse dye, a dispersant, a water-soluble organic solvent, a penetrability-imparting solvent, and water, wherein the water-soluble organic solvent contains glycerin and propylene glycol, and the penetrability-imparting solvent contains one or more solvents selected from the group consisting of 1,5-pentanediol, 1,2-butanediol, 3-methyl-1,5-pentanediol, and polyethylene glycol monomethyl ether.

[0009] According to this embodiment, an ink composition having excellent storage stability and ejection stability at a higher level can be obtained.

[0010] Although the reason why this embodiment provides such excellent effects is not clear, the inventors speculate as follows.

[0011] Conventional water-soluble inkjet ink compositions for dye printing, which contain a disperse dye, a dispersant, and water, also contain a water-soluble organic solvent. However, the water-soluble organic solvent does not allow the disperse dye and the dispersant to be suitably dissolved in water, making it difficult to obtain an ink composition with excellent storage stability and ejection stability.

[0012] However, the water-soluble dye printing inkjet ink composition of this embodiment contains a disperse dye, a dispersant, water, a specific water-soluble organic solvent, and a specific penetrability-imparting solvent. The specific penetrability-imparting solvent has a relatively high affinity with the disperse dye and the dispersant. The specific penetrability-imparting solvent also has a relatively high affinity with the specific water-soluble organic solvent. Furthermore, the specific penetrability-imparting solvent and the specific water-soluble organic solvent have a relatively high affinity, and the specific water-soluble organic solvent has even higher hydrophilicity than the other water-soluble organic solvents. By including such a specific water-soluble organic solvent and a specific penetrability-imparting solvent in the ink composition, the disperse dye and the dispersant can be more suitably dissolved in water. Therefore, it is believed that this embodiment can provide an ink composition with excellent storage stability and ejection stability at a higher level. However, the reasons for this are not limited to these.

[0013] Next, each component contained in the ink composition will be described.

[0014] 1.1. Disperse dye The ink composition includes a disperse dye. Disperse dyes are usually particulate colorants that are dispersed in a dispersion medium by a dispersant. Disperse dyes are usually nonionic dyes that have a hydrophilic group and a moderate polar group. Disperse dyes may be used alone or in combination of two or more.

[0015] Disperse dyes include, for example, CI Disperse Yellow, CI Disperse Red, CI Disperse Blue, CI Disperse Orange, CI Disperse Violet, CI Disperse Green, CI Disperse Brown, and CI Disperse Black.

[0016] As the disperse dye, a sublimable dye is preferable. In this specification, the term "sublimable dye" refers to a dye that has the property of being sublimated by heating.

[0017] Specific examples of disperse dyes that are sublimable dyes include CI Disperse Yellow 3, 7, 8, 23, 39, 51, 54, 60, 71, and 86; CI Disperse Orange 1, 1:1, 5, 20, 25, 25:1, 33, 56, and 76; CI Disperse Brown 2; CI Disperse Red 11, 50, 53, 55, 55:1, 59, 60, 65, 70, 75, 93, 146, 158, 190, and 190:1; 207, 239, and 240; CI Vat Red 41; CI Disperse Violet 8, 17, 23, 27, 28, 29, 36, and 57; CI Disperse Blue 14, 19, 26, 26:1, 35, 55, 56, 58, 64, 64:1, 72, 72:1, 81, 81:1, 91, 95, 108, 131, 141, 145, and 359; CI Solvent Blue 36, 63, 105, and 111.

[0018] The disperse dye preferably contains one or more selected from the group consisting of CI Disperse Yellow, CI Disperse Red, CI Disperse Blue, and CI Disperse Orange, more preferably contains one or more selected from the group consisting of CI Disperse Yellow 54, CI Disperse Red 60, CI Disperse Blue 359, and CI Disperse Orange 25, and even more preferably contains one or more selected from the group consisting of CI Disperse Red 60 and CI Disperse Orange 25. When the disperse dye contains any of the above disperse dyes, it tends to be possible to obtain an ink composition having even higher levels of excellent storage stability and ejection stability.

[0019] The content of the disperse dye relative to the total amount of the ink composition is preferably 5.0% by mass or more, more preferably 5.1% by mass or more and 20.0% by mass or less, even more preferably 5.2% by mass or more and 15.0% by mass or less, and even more preferably 5.3% by mass or more and 10.0% by mass or less. When the content of the disperse dye is within the above range, it tends to be possible to obtain an ink composition with even higher levels of excellent storage stability and ejection stability.

[0020] 1.2.Dispersants The ink composition contains a dispersant, and one type of dispersant may be used alone, or two or more types may be used in combination. The dispersant has the function of stably dispersing the disperse dye in the ink. Examples of the dispersant include anionic dispersants, nonionic dispersants, and polymer dispersants. Among these, anionic dispersants are preferred because they provide superior dispersion stability to the inkjet ink composition.

[0021] As the anionic dispersant, a salt of a formalin condensate of an aromatic sulfonic acid is preferred. Examples of the "aromatic sulfonic acid" in the salt of a formalin condensate of an aromatic sulfonic acid include naphthalene sulfonic acid, creosote oil sulfonic acid, cresol sulfonic acid, phenol sulfonic acid, alkylnaphthalene sulfonic acids such as β-naphthol sulfonic acid, methylnaphthalene sulfonic acid, and butylnaphthalene sulfonic acid, a mixture of β-naphthalene sulfonic acid and β-naphthol sulfonic acid, a mixture of cresol sulfonic acid and 2-naphthol-6-sulfonic acid, and lignin sulfonic acid. Examples of the "salt" include sodium salts.

[0022] The anionic dispersant preferably contains one or more selected from the group consisting of sodium salts of naphthalenesulfonic acid-formaldehyde condensates and sodium salts of ligninsulfonic acid, and more preferably contains sodium salts of naphthalenesulfonic acid-formaldehyde condensates. These anionic dispersants have a greater effect of improving the dispersion stability of disperse dyes, and tend to enable the production of ink compositions with even higher levels of excellent storage stability and ejection stability.

[0023] Examples of nonionic dispersants include ethylene oxide adducts of phytosterol and ethylene oxide adducts of cholestanol.

[0024] Examples of polymer dispersants include partial alkyl esters of polyacrylic acid, polyalkylene polyamines, polyacrylates, styrene-acrylic acid copolymers, and vinylnaphthalene-maleic acid copolymers.

[0025] The content of the dispersant is preferably 0.1% by mass to 30.0% by mass, more preferably 1.0% by mass to 20.0% by mass, and even more preferably 5.0% by mass to 10.0% by mass, relative to 100% by mass of the ink, which tends to make it easier to adjust the viscosity of the ink to one more suitable for the inkjet method.

[0026] 1.3. Water-soluble organic solvents The ink composition contains a water-soluble organic solvent, which includes glycerin and propylene glycol. By using glycerin and propylene glycol as the water-soluble organic solvent, the disperse dye and dispersant can be more suitably dissolved in water, and therefore an ink composition having excellent storage stability and ejection stability at a higher level can be obtained.

[0027] Glycerin and propylene glycol also function as excellent moisturizers.

[0028] The total content of glycerin and propylene glycol as water-soluble organic solvents is preferably 11.0% by mass or more and 30.0% by mass or less, and more preferably 16.0% by mass or more and 24.0% by mass or less, relative to the total amount of the ink composition. When the total content is within this range, an ink composition with even higher levels of excellent storage stability and ejection stability tends to be obtained.

[0029] The glycerin content is preferably 10.0% by mass or more and 20.0% by mass or less, and more preferably 13.0% by mass or more and 17.0% by mass or less, relative to the total amount of the ink composition. When the glycerin content is within this range, it tends to be possible to obtain an ink composition with even higher levels of excellent storage stability and ejection stability.

[0030] The content of propylene glycol is preferably 1.0% by mass or more and 10.0% by mass or less, and more preferably 3.0% by mass or more and 7.0% by mass or less, relative to the total amount of the ink composition. When the content of propylene glycol is within the above range, it tends to be possible to obtain an ink composition with even higher levels of excellent storage stability and ejection stability.

[0031] 1.4. Penetrating Solvent The ink composition includes a penetrating solvent, the penetrating solvent including at least one solvent selected from the group consisting of 1,5-pentanediol, 1,2-butanediol, 3-methyl-1,5-pentanediol, and polyethylene glycol monomethyl ether. The specific penetrability-imparting solvents described above have a relatively high affinity with the disperse dye and the dispersant, and therefore, by using the specific penetrability-imparting solvents described above, the disperse dye and the dispersant can be more suitably dispersed. As a result, an ink composition having excellent storage stability and ejection stability at a higher level can be obtained. The penetrability-imparting solvents may be used alone or in combination of two or more.

[0032] The permeability-imparting solvent preferably contains polyethylene glycol monomethyl ether, which has a greater effect of improving the dispersion stability of the disperse dye, and tends to enable the production of an ink composition having even more excellent storage stability and ejection stability.

[0033] The content of the penetrability-imparting solvent is preferably from 0.5 to 10.0% by mass, more preferably from 1.0 to 5.0% by mass, relative to the total amount of the ink composition. When the content of the penetrability-imparting solvent is within the above range, it tends to be possible to obtain an ink composition with even higher levels of excellent storage stability and ejection stability.

[0034] 1.5.Water The ink composition includes water. Examples of water include pure water such as ion-exchanged water, ultrafiltered water, reverse osmosis water, and distilled water, as well as ultrapure water from which ionic impurities have been removed as much as possible. Water that has been sterilized by ultraviolet irradiation or the addition of hydrogen peroxide is preferred because it can inhibit the growth of mold and bacteria when the ink composition is stored for a long period of time.

[0035] The water content is preferably 30.0% by mass or more and 80.0% by mass or less relative to the total amount of the ink composition. By keeping the water content within this range, an increase in the viscosity of the ink composition can be suppressed.

[0036] 1.6.Surfactants The ink composition may contain a surfactant. The surfactant has the function of reducing the surface tension of the ink composition and adjusting the wettability with the recording medium. Examples of the surfactant include acetylene glycol surfactants and silicone surfactants. The surfactant may be used alone or in combination of two or more.

[0037] Examples of acetylene glycol surfactants include Surfynol (registered trademark) 104, 104E, 104H, 104A, 104BC, 104DPM, 104PA, 104PG-50, 104S, 420, 440, 465, 485, SE, SE-F, 504, 61, DF37, CT111, CT121, CT131, CT136, TG, GA, and DF110D (manufactured by Nissin Chemical Industry Co., Ltd.); Olfine (registered trademark) Examples of the acetylene compounds include (trademarks) B, Y, P, A, STG, SPC, E1004, E1010, PD-001, PD-002W, PD-003, PD-004, EXP.4001, EXP.4036, EXP.4051, AF-103, AF-104, AK-02, and SK-14; AE-3 (manufactured by Nissin Chemical Industry Co., Ltd.); and Acetylenol (registered trademark) E00, E00P, E40, and E100 (manufactured by Kawaken Fine Chemicals Co., Ltd.).

[0038] Examples of silicone surfactants include polysiloxane compounds such as polyether-modified organosiloxanes. Commercially available polyether-modified organosiloxanes include, for example, BYK-306, BYK-307, BYK-333, BYK-341, BYK-345, BYK-346, and BYK-348 (manufactured by BYK Japan K.K.), KF-351A, KF-352A, KF-353, KF-354L, KF-355A, KF-615A, KF-945, KF-640, KF-642, KF-643, KF-6004, KF-6020, X-22-4515, KF-6011, KF-6012, KF-6015, and KF-6017 (manufactured by Shin-Etsu Chemical Co., Ltd.).

[0039] The surfactant preferably contains a silicone surfactant, and more preferably contains a polysiloxane compound. When the ink composition contains the surfactant, it tends to be possible to obtain an ink composition having even higher levels of excellent storage stability and ejection stability.

[0040] The content of the surfactant is preferably 0.01% by mass or more and 10.0% by mass or less, more preferably 0.05% by mass or more and 5.0% by mass or less, and even more preferably 0.1% by mass or more and 1.0% by mass or less, relative to the total amount of the ink composition. When the content of the surfactant is within the above range, it tends to be possible to obtain an ink composition with even higher levels of excellent storage stability and ejection stability.

[0041] 1.7. pH adjusters The ink composition may include a pH adjuster. When the ink composition contains a pH adjuster, it tends to be possible to obtain an ink composition having even higher levels of excellent storage stability and ejection stability. The pH adjuster may be used alone or in combination of two or more types.

[0042] Examples of pH adjusters include suitable combinations of acids, bases, weak acids, and weak bases. Examples of the acids and bases used in such combinations include inorganic acids such as sulfuric acid, hydrochloric acid, and nitric acid; inorganic bases such as lithium hydroxide, sodium hydroxide, potassium hydroxide, potassium dihydrogen phosphate, disodium hydrogen phosphate, potassium carbonate, sodium carbonate, sodium bicarbonate, and ammonia; organic bases such as triethylamine, trimethylamine, diethylethanolamine, triethanolamine, diethanolamine, monoethanolamine, tripropanolamine, triisopropanolamine, diisopropanolamine, and trishydroxymethylaminomethane (THAM); adipic acid, citric acid, succinic acid, lactic acid, N,N-bis(2-hydroxyethyl) Examples of suitable buffers include 2-aminoethanesulfonic acid (BES), 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid (HEPES), morpholinoethanesulfonic acid (MES), morpholinopropanesulfonic acid (MOPS), carbamoylmethyliminobisacetic acid (ADA), piperazine-1,4-bis(2-ethanesulfonic acid) (PIPES), N-(2-acetamido)-2-aminoethanesulfonic acid (ACES), cholamine hydrochloride, N-tris(hydroxymethyl)methyl-2-aminoethanesulfonic acid (TES), acetamidoglycine, tricine, glycinamide, Good's buffers such as bicine, phosphate buffer, citrate buffer, and Tris buffer. In addition, since the pH buffering effect can be more stably obtained, tertiary amines such as triethanolamine and triisopropanolamine, or carboxyl group-containing organic acids such as adipic acid, citric acid, succinic acid, and lactic acid may be included as part or all of the pH adjuster. Furthermore, buffering agents such as sodium acetate, ammonium acetate, sodium formate, ammonium formate, sodium carbonate, sodium bicarbonate, potassium bicarbonate, monosodium phosphate, monopotassium phosphate, disodium phosphate, and trisodium phosphate may also be used together with the pH adjuster.

[0043] The pH adjuster preferably includes triethanolamine. When the ink composition includes the above pH adjuster, it tends to be possible to obtain an ink composition having even higher levels of excellent storage stability and ejection stability.

[0044] The content of the pH adjuster is preferably 0.05% by mass or more and 5.0% by mass or less, and more preferably 0.1% by mass or more and 3.0% by mass or less, relative to the total amount of the ink composition. When the content of the pH adjuster is within the above range, it tends to be possible to obtain an ink composition with even higher levels of excellent storage stability and ejection stability.

[0045] 1.8.Other Ingredients In addition to the above-mentioned components, the ink composition may contain various additives that are typically used in ink compositions, such as a solubilizing agent, a viscosity modifier, an antioxidant, an ultraviolet absorber, an oxygen absorber, a preservative, an antifungal agent, a corrosion inhibitor, and a chelating agent for capturing metal ions that affect dispersion. The additives may be used alone or in combination of two or more.

[0046] Preservatives include, for example, sodium pentachlorophenol, sodium 2-pyridinethiol-1-oxide, and 1,2-dibenzinethiazolin-3-one.

[0047] Commercially available preservatives can also be used, such as CRL, BND, GXL, XL-2, and TN (all trade names) from the Proxel (registered trademark) series manufactured by Lonza Japan Co., Ltd. One type of preservative may be used alone, or two or more types may be used in combination.

[0048] The content of each additive may be 0.01% by mass or more and 5.0% by mass or less relative to the total amount of the ink composition.

[0049] 1.9. Physical properties of ink composition 1.9.1.Viscosity The viscosity of the ink composition at 20° C. is preferably 1.5 mPa·s or more and 10.0 mPa·s or less, and more preferably 2.0 mPa·s or more and 78.0 mPa·s or less. When the viscosity of the ink composition is within the above range, it tends to be possible to obtain an ink composition with even higher levels of excellent storage stability and ejection stability.

[0050] The viscosity of the ink composition can be measured using a viscoelasticity measuring device (viscoelasticity tester MCR-300, manufactured by Anton Paar Japan Co., Ltd.). Specifically, the temperature of the ink composition is adjusted to 20°C, and the ink is heated at a shear rate of 200 s -1 It can be measured by reading the shear viscosity (mPa·s) at

[0051] 1.9.2.Surface tension The surface tension of the ink composition is preferably 10 mN / m or more and 40 mN / m or less, and more preferably 22 mN / m or more and 35 mN / m or less, at 25° C. When the surface tension of the ink composition is within the above range, it tends to be possible to obtain an ink composition having even higher levels of excellent storage stability and ejection stability.

[0052] The surface tension of the ink composition can be measured using a surface tensiometer CBVP-Z (trade name, manufactured by Kyowa Interface Science Co., Ltd.) as the surface tension when a platinum plate is wetted with the ink composition at room temperature and normal pressure.

[0053] 1.9.3.pH The pH of the ink composition is preferably 7.0 or more and 9.5 or less at 25° C. When the pH of the ink composition is within the above range, it tends to be possible to obtain an ink composition having even higher levels of excellent storage stability and ejection stability.

[0054] The pH of the ink composition can be measured, for example, by using a benchtop pH meter and immersing the electrode portion in the ink composition.

[0055] 1.9.4.Particle size The particle size of the ink composition is an average particle size, and in this specification, the particle size means the particle size at which the frequency reaches 50% in a particle distribution measured by a dynamic light scattering method, cumulatively calculating the particle size from the smallest particle size side. This can be determined, for example, by measurement using a particle size distribution measuring device Nanotrac Wave-EX (manufactured by Nikkiso Co., Ltd.).

[0056] The particle size of the ink composition at 25°C is preferably 80 nm or more and 200 nm or less, and more preferably 100 nm or more and 170 nm or less.

[0057] A change in particle size of the disperse dye dispersed in the dispersion medium by the dispersant, particularly an increase in particle size, means a decrease in dispersion stability, and an inkjet composition with decreased dispersion stability also has decreased ejection stability.

[0058] 1.10. Method for producing ink composition The ink composition can be prepared by mixing a disperse dye, a dispersant, a water-soluble organic solvent, a penetrability-imparting solvent, water, and optionally a surfactant, a pH adjuster, and other components in any order, and then removing impurities and foreign matter by filtration or other means as necessary. The components can be mixed by sequentially adding the components to a container equipped with a stirring device such as a mechanical stirrer or a magnetic stirrer, stirring, and mixing them. Filtration methods include centrifugal filtration and filter filtration.

[0059] Alternatively, a disperse dye, a dispersant, and water may be mixed in any order and dispersed using a paint shaker or the like to obtain a dye dispersion, and then the ink composition may be prepared using the dye dispersion, a water-soluble organic solvent, and a penetrability-imparting solvent. This allows the disperse dye to be more satisfactorily dispersed in the ink composition.

[0060] 2. Inkjet recording method The recording method according to this embodiment includes at least an ink deposition step in which ink is ejected from a recording head and deposited on transfer paper, and a transfer step in which dye contained in the ink is transferred from the transfer paper to a recording medium by sublimation transfer. The recording method according to this embodiment may also include other steps as necessary. FIG. 1 shows an example of the inkjet recording method according to this embodiment. This inkjet recording method includes, in this order, an ink deposition step and a heating step. Next, a recording medium, an inkjet recording apparatus that can be used in the recording method, and each step will be described.

[0061] An example of a recording method utilizing such sublimation transfer is a method in which a transfer image is formed by printing ink onto a sheet-like intermediate transfer medium such as transfer paper using ink by an inkjet method, and then the intermediate transfer medium is overlaid on a recording medium (transfer destination medium) such as fabric, and the transfer image obtained by heating is sublimation transferred.

[0062] 2.1.Ink application process In this process, an inkjet method is used to eject ink from a recording head and deposit it on the recording surface of transfer paper, which is an intermediate transfer medium, to form a transferred image. The ink ejection by the inkjet method can be performed using, for example, a droplet ejection device such as an inkjet recording device.

[0063] The inkjet recording device is not particularly limited as long as it has at least an ink container, such as a cartridge or tank, that contains ink, and a recording head connected to the ink container, and is capable of ejecting ink from the recording head to form an image on a transfer paper, which is an intermediate transfer medium. In addition, either a serial type or a line type inkjet recording device can be used. These types of inkjet recording devices are equipped with a recording head, which ejects ink droplets intermittently and in a predetermined volume from the nozzle holes of the recording head at predetermined timing while changing the relative positional relationship between the transfer paper and the recording head. This allows the ink to adhere to the transfer paper, forming a predetermined transfer image.

[0064] Generally, in a serial inkjet recording device, the direction of transfer paper transport and the direction of reciprocating motion of the recording head intersect, and the relative positional relationship between the transfer paper and the recording head is changed by combining the reciprocating motion of the recording head and the transfer paper transport motion. In this case, the recording head generally has a plurality of nozzle holes, and a row of the nozzle holes, i.e., a nozzle row, is formed along the transfer paper transport direction. The recording head may also have a plurality of nozzle rows formed depending on the types and numbers of the first to fourth inks.

[0065] Generally, in a line-type inkjet recording device, the recording head does not reciprocate, but changes the relative positional relationship between the transfer paper and the recording head as the transfer paper is transported. Even in this case, the recording head generally has a plurality of nozzle holes arranged in a nozzle row that runs in a direction that intersects with the transport direction of the transfer paper.

[0066] The inkjet recording method is not particularly limited as long as it can eject ink as droplets from minute nozzle holes and cause the droplets to adhere to transfer paper. For example, the inkjet recording method can be a piezo method or a method in which ink is ejected by bubbles generated by heating the ink. In this embodiment, it is preferable to use the piezo method from the viewpoint of ink resistance to deterioration, etc.

[0067] The inkjet recording apparatus may employ known components such as a heating unit, a drying unit, a roll unit, and a winding unit.

[0068] In this embodiment, the transfer paper serving as the intermediate transfer medium may be, for example, a recording medium provided with an ink-receiving layer, such as plain paper, inkjet paper, or coated paper. However, paper provided with an ink-receiving layer made of inorganic fine particles such as silica is preferred. This allows for the production of an intermediate recorded product in which bleeding and other issues are suppressed on the recording surface during the drying process of the ink applied to the intermediate transfer medium. Furthermore, such a medium makes it easier to retain the dye on the recording surface, allowing for more efficient dye sublimation in the subsequent transfer process.

[0069] 2.2.Transfer process The recording method according to this embodiment includes a transfer step in which the recording surface of transfer paper to which ink has been applied is placed opposite a recording medium such as a polyester fabric that is the object to be printed, that is, the fabric, etc. is placed on the recording surface of the transfer paper, and the paper is heated to sublimate the dye into the object to be printed and transfer it to the fabric, etc. This results in a printed object, i.e., a printed matter, in which the fabric, etc. is used as the object to be printed.

[0070] The heating temperature in the transfer step is, for example, preferably 160° C. or higher and 220° C. or lower, and more preferably 170° C. or higher and 200° C. or lower. This allows sufficient energy to be applied to transfer the dye to the object to be printed, thereby improving the productivity of the printed material.

[0071] The heating time in the transfer step depends on the heating temperature, but is preferably 30 to 90 seconds, more preferably 45 to 60 seconds, which provides sufficient energy to transfer the dye to the object to be printed, thereby improving the productivity of the printed material.

[0072] The transfer step may be carried out by heating the transfer paper on which the ink has been applied while it is facing the item to be printed, but it is preferable to carry out the transfer step by heating the transfer paper and the item to be printed while they are in close contact with each other, thereby obtaining, for example, a printed item in which a clearer image is recorded on fabric or the like.

[0073] Examples of recording media, i.e., materials to be printed, include polyester fabrics, which are hydrophobic fiber fabrics, but sheet-like objects such as resin films, and objects with three-dimensional shapes other than sheet shapes, such as spherical, rectangular, or curved objects, may also be used.

[0074] 2.3.Other processes The recording method according to this embodiment may include a step of heating the transfer paper after the ink application step. This step involves heating the transfer paper after ejecting and applying ink to it. By performing this step, the drying of the ink applied in the ink application step is accelerated, and image bleeding is suppressed, and set-off may also be suppressed. Set-off refers to the phenomenon in which ink components migrate to the back side of the transfer paper that is in contact with the recording surface when the transfer paper is stacked, for example, by being wound up on a roll.

[0075] The temperature that the transfer paper reaches in this step is preferably 60° C. or higher, and more preferably 70° C. to 120° C. If the temperature is within this range, the dye is less likely to sublimate and a good drying speed can be achieved. [Example]

[0076] The present invention will be described in more detail below using examples and comparative examples, but the present invention is not limited to the following examples.

[0077] 1. Preparation of ink composition for dye solubility evaluation (Ink compositions 1 to 3) Each component was placed in a mixing tank so as to have the composition shown in Table 1, and mixed and stirred with a magnetic stirrer for 2 hours to obtain ink compositions 1 to 3 for dye solubility evaluation. The values ​​in Table 1 indicate mass %. Mass % of disperse dye is shown as solid content. Ion-exchanged water was used and added so that the mass of each ink composition was 100.0 mass %. Each component shown in Table 1 is as described below.

[0078] 2. Preparation of inkjet ink composition for dye printing (Examples 1 to 12 and Comparative Examples 1 to 18) Each component was placed in a mixing tank so as to obtain the composition shown in Tables 2 to 4, and the components were mixed and stirred for 2 hours using a magnetic stirrer. The mixture was then filtered through a membrane filter with a pore size of 1 μm, thereby obtaining inkjet ink compositions for dye textile printing according to the examples and comparative examples. The numerical values ​​in Tables 2 to 4 indicate mass %. The components shown in Tables 1 to 4 are as follows.

[0079] [Disperse dye] Disperse Red 60...CI Disperse Red 60 (commercially available) Disperse Yellow 54: CI Disperse Yellow 54 (commercially available) Disperse Blue 359: CI Disperse Blue 359 (commercially available) Disperse Orange 25: CI Disperse Orange 25 (commercially available)

[0080] [Dispersant] Naphthalenesulfonic acid formalin condensate sodium...Naphthalenesulfonic acid formalin condensate sodium Sodium lignosulfonate: Sodium lignosulfonate

[0081] [Water-soluble organic solvent] Glycerin Propylene glycol

[0082] [Penetration-imparting solvent] 1,5-Pentanediol 1,2-Butanediol 3-Methyl-1,5-pentanediol Polyethylene glycol monomethyl ether

[0083] [Other water-soluble organic solvents] N-Hydroxyethyl-2-pyrrolidone 1,2-Hexanediol 2-Pyrrolidone 2,3-Butanediol Ethylene glycol monoisopropyl ether

[0084] [Surfactant] BYK348: BYK-348 (a silicone surfactant manufactured by BYK Japan Co., Ltd.)

[0085] [pH adjuster] Triethanolamine

[0086] 3. Evaluation Method 3.1. Dye solubility First, each of the dye solubility evaluation ink compositions 1 to 3 obtained above was added to a penetrability-imparting solvent or other organic solvent to obtain a dispersion. Specifically, the dye solubility evaluation ink composition and the penetrability-imparting solvent or other organic solvent were placed in a mixing vessel so that the total amount of solids of the disperse dye contained in the dye solubility evaluation ink composition was 5.0 mass% relative to the penetrability-imparting solvent or other organic solvent, and the mixture was mixed and stirred with a magnetic stirrer for 2 hours to obtain each dispersion. Each of the resulting dispersions was heated at 60°C for 1 hour. The dispersions were then cooled to room temperature (25°C) and left at that temperature for 4 days. After leaving the dispersions, they were visually inspected and the dye solubility was evaluated according to the following criteria. In addition, dispersions in which no penetrability-imparting solvent or other organic solvent was added to the ink composition, i.e., ink compositions 1 to 3 for dye solubility evaluation, were also heated in the same manner as above and left to stand at room temperature for 4 days, and the dye solubility of the dispersions after standing was evaluated. The results are shown in Table 5. (standard) A: The disperse dye dissolved in the dispersion liquid, and no insoluble components were observed. B: The disperse dye was dissolved in the dispersion liquid, but insoluble components were observed. C: A part of the disperse dye did not dissolve in the dispersion liquid, and insoluble components were observed.

[0087] 3.2. Ink storage stability Approximately 50 mL of each of the inkjet ink compositions for dye textile printing in Examples 1 to 4 and Comparative Examples 1 to 6 was degassed and sealed in an aluminum pack capable of sealing the ink. Two aluminum packs were prepared for each ink composition. One of the aluminum packs was left to stand at 60° C. for 5 days, and then cooled to room temperature (25° C.) After cooling, the ink composition was removed from the aluminum pack to obtain ink composition 1 for evaluation. The other aluminum pack was left at room temperature for 5 days, after which the ink composition was removed from the aluminum pack to obtain ink composition 2 for evaluation. The viscosity, surface tension, particle size, and pH of each of the evaluation ink compositions 1 and 2 were measured, and if the ink composition satisfied the following criteria, it was rated as A. The A ratings were counted, and inkjet ink compositions for dye textile printing that received three or more A ratings were rated as A, and the rest were rated as D, thereby evaluating the ink storage stability of the ink compositions. The results are shown in Table 6. (Standard: A rating) Viscosity: The viscosity of the ink composition 1 for evaluation was the same as that of the ink composition 2 for evaluation. Surface tension: The surface tension of the ink composition 1 for evaluation was the same as that of the ink composition 2 for evaluation. Particle size: The particle size of the ink contained in evaluation ink composition 1 changed by 15 nm or less compared to the particle size of the disperse dye contained in evaluation ink composition 2. pH: The pH of evaluation ink composition 1 varied within ±0.2 compared to the pH of evaluation ink composition 2.

[0088] 3.3. Occurrence of foreign matter Approximately 10 mL of each of the inkjet ink compositions for dye textile printing in Examples 1 to 12 and Comparative Examples 1 to 18 was filled into a hermetically sealed glass storage bottle and left to stand at 60°C for 5 days. After that, the bottle was cooled to room temperature (25°C), and the ink composition was removed from the storage bottle to obtain evaluation ink composition 3. Each evaluation ink composition 3 was filtered through a metal mesh filter with a 10 μm diameter, and the number of solids remaining on the metal mesh filter per 1 mm square was counted, and the occurrence of foreign solids was evaluated according to the following criteria. The results are shown in Table 7. (standard) A: No solid matter was found per 1mm square. B: Solid matter was observed per 1 mm square, but the number was not enough to pose a practical problem. C: Solid matter was observed per 1 mm square, and the number was problematic for practical use.

[0089] 3.4. Discharge reliability Each of the inkjet ink compositions for dye textile printing in Examples 1 to 4 and Comparative Examples 1 to 6 was filled into an ink cartridge of an inkjet printer PX-930G (trade name, manufactured by Seiko Epson Corporation). The ink compositions were then ejected from all nozzles, and a confirmation pattern of the landing position was recorded. The confirmation pattern confirmed that all ink compositions were ejected normally. The printer was then turned off, the print head was moved to its normal standby position, and after confirming that the inkjet head was capped, the printer, with the ink cartridge installed, was left in a thermostatic chamber at 40°C and 20% RH. The printer was then removed from the thermostatic chamber and allowed to cool to room temperature (25°C). The printer was turned on, and the ink composition was ejected from all nozzles of the head to confirm whether printing was possible normally. If there were any nozzles that could not eject the ink composition, the head was cleaned, and the ink composition was ejected from all nozzles. The number of cleanings required until printing was possible normally was counted. Based on the number of cleanings, ejection reliability was evaluated according to the following criteria. The results are shown in Table 6. In Table 6, "-" indicates that the test was not conducted. (standard) A: I was able to print normally within two cleaning cycles. B: The clogging was resolved after 3 to 6 cleanings, and normal printing was possible. C: The clogging could not be cleared even after cleaning was performed 7 times or more.

[0090] 3.5.Discharge stability Each of the inkjet ink compositions for dye textile printing in Examples 1 to 4 and Comparative Examples 1 to 6 was filled into an ink cartridge of an inkjet printer PX-930G (trade name, manufactured by Seiko Epson Corporation). The printer filled with the ink composition was then left at room temperature for 20 minutes with the inkjet head uncapped. After leaving the printer, the head was cleaned once, 20 solid patterns were printed, and then an ink check pattern was printed and visually inspected for missing nozzles and misalignment. Based on the observation results, the ejection stability was evaluated according to the following criteria. The results are shown in Table 6. In Table 6, "-" indicates that the test was not conducted. (standard) A: Of the 180 nozzles, no missing or twisted nozzles were found. B: Of 180 nozzles, 1 to 30 nozzles were found to be missing or twisted.

[0091] As shown in Tables 5 to 7, it was found that the ink composition of this embodiment had excellent storage stability and ejection stability at a higher level.

[0092] As shown in Tables 6 and 7, it was found that when the sodium salt of naphthalenesulfonic acid formalin condensate was used as the dispersant, an ink composition having even higher levels of excellent storage stability and ejection stability could be obtained.

[0093] As shown in Tables 6 and 7, it was found that ink compositions containing one or more disperse dyes selected from the group consisting of CI Disperse Red 60 and CI Disperse Orange 25 had even higher levels of excellent storage stability and ejection stability.

[0094] As shown in Tables 5 to 7, it was found that when polyethylene glycol monomethyl ether was used as the permeability-imparting solvent, an ink composition having even higher levels of excellent storage stability and ejection stability could be obtained.

Claims

1. An ink composition comprising a disperse dye, a dispersant, a water-soluble organic solvent, a penetrability-imparting solvent, and water, the water-soluble organic solvent contains glycerin and propylene glycol, the penetrating solvent comprises one or more selected from the group consisting of 1,5-pentanediol, 1,2-butanediol, 3-methyl-1,5-pentanediol, and polyethylene glycol monomethyl ether; Inkjet ink composition for dye textile printing.

2. The dispersant contains at least one selected from the group consisting of a sodium salt of a naphthalenesulfonic acid-formalin condensate and a sodium salt of lignosulfonic acid. The ink-jet ink composition for dye textile printing according to claim 1 .

3. The disperse dye includes one or more selected from the group consisting of C.I. Disperse Red 60 and C.I. Disperse Orange 25, The ink-jet ink composition for dye textile printing according to claim 1 .

4. the content of the disperse dye is 5.0% by mass or more relative to the total amount of the ink composition, the content of the dispersant is 5.0% by mass or more relative to the total amount of the ink composition; The ink-jet ink composition for dye textile printing according to claim 1 .

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