Inkjet ink composition and ink container

Abstract

To provide an ink composition that effectively prevents the generation of foreign matter as an agglomerate caused by a material in an ink-housing body.SOLUTION: An inkjet ink composition includes: a sublimation dye; an anionic dispersant; and an anionic surface active agent, where the sublimation dye includes at least one selected from the group consisting of C.I.Disperse Orange 25, C.I.Disperse Orange 80, C.I. Solvent Orange 60, C.I.Disperse Brown 27, C.I.Disperse Violet 28, and C.I. Solvent Violet 13, and the anionic surface active agent includes at least one selected from the group consisting of polyoxyethylene alkyl ether sulfuric acid salt, polyoxyethylene alkenyl ether sulfuric acid salt, polyoxyethylene aryl ether sulfuric acid salt, and polyoxyethylene alkyl ether phosphoric acid salt.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to an inkjet ink composition and an ink container.

Background Art

[0002] The inkjet recording method has been attempted not only for recording images on media such as paper but also for dyeing fabrics, and various ink compositions and recording methods have been studied for inkjet dyeing. For example, Patent Document 1 discloses an aqueous inkjet composition containing at least one specific dye selected from the group consisting of C.I. Disperse Orange 25 and C.I. Disperse Brown 27, an anionic dispersant, a polyalkylene glycol, a derivative of a polyalkylene glycol, and a substance A which is at least one selected from the group consisting of phenylazo compounds different from the specific dye.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, the aqueous inkjet ink composition described in Patent Document 1 has a problem that foreign matters as aggregates due to materials are generated in the ink container.

Means for Solving the Problems

[0005] The present invention relates to an inkjet ink composition comprising a sublimable dye, an anionic dispersant, and an anionic surfactant, wherein the sublimable dye comprises one or more selected from the group consisting of CI Disperse Orange 25, CI Disperse Orange 80, CI Disperse Brown 27, CI Solvent Orange 60, CI Solvent Violet 13, and CI Disperse Violet 28, and the anionic surfactant comprises one or more selected from the group consisting of polyoxyethylene alkyl ether sulfate, polyoxyethylene alkenyl ether sulfate, polyoxyethylene aryl ether sulfate, and polyoxyethylene alkyl ether phosphate. [Brief explanation of the drawing]

[0006] [Figure 1] Figure 1 is a perspective view showing an example of an ink container. [Modes for carrying out the invention]

[0007] The following describes in detail embodiments of the present invention (hereinafter referred to as "this embodiment"), but the present invention is not limited thereto, and various modifications are possible without departing from its spirit.

[0008] 1. Inkjet ink composition The inkjet ink composition of this embodiment (hereinafter also referred to as "ink composition") comprises a sublimable dye, an anionic dispersant, and an anionic surfactant, wherein the sublimable dye comprises one or more selected from the group consisting of CI Disperse Orange 25, CI Disperse Orange 80, CI Disperse Brown 27, CI Solvent Orange 60, CI Solvent Violet 13, and CI Disperse Violet 28, and the anionic surfactant comprises one or more selected from the group consisting of polyoxyethylene alkyl ether sulfate, polyoxyethylene alkenyl ether sulfate, polyoxyethylene aryl ether sulfate, and polyoxyethylene alkyl ether phosphate.

[0009] According to this embodiment, an ink composition can be obtained in which the generation of foreign matter as aggregates caused by the materials within the ink container is effectively prevented.

[0010] Although the factors that contribute to the excellent effects obtained by this embodiment are not entirely clear, the inventors of the present invention deduce the following: Firstly, when ink containers are stored for a long period of time with their inner walls tightly pressed together, sandwiching the internal ink composition, foreign matter in the form of aggregates due to the materials is likely to occur. In particular, when the inner wall material of the ink container is a polyolefin such as polyethylene, and the contained ink composition contains one or more sublimable dyes selected from the group consisting of CI Disperse Orange 25, CI Disperse Orange 80, CI Disperse Brown 27, CI Solvent Orange 60, CI Solvent Violet 13, and CI Disperse Violet 28, foreign matter tends to occur significantly. In areas where the inner walls of the ink containers are in close proximity, creating a confined space, the moisture contained in the ink composition is absorbed by polyolefins such as polyethylene, causing the inner walls to swell and the dye concentration to increase locally. This is thought to worsen the dispersion of the dye in the ink composition, resulting in the generation of foreign matter. Furthermore, while aggregation is more likely to occur in high-temperature environments, it is also estimated that when heat is applied to the ink contents, moisture absorption by polyolefins progresses more rapidly, making aggregation even more likely.

[0011] On the other hand, the ink composition of this embodiment contains, along with a sublimable dye, an anionic dispersant and an anionic surfactant comprising one or more selected from the group consisting of polyoxyethylene alkyl ether sulfate, polyoxyethylene alkenyl ether sulfate, polyoxyethylene aryl ether sulfate, and polyoxyethylene alkyl ether phosphate. The anionic dispersant is adsorbed onto the dye, but these anionic surfactants are more readily adsorbed by the dye, so the charge of the dye tends to be more negatively biased compared to an ionic composition containing only anionic dispersant. As a result, the electrostatic repulsion force is improved, and the dispersion of the dye is stabilized. Furthermore, these anionic surfactants are more readily adsorbed onto the polyolefin that forms the inner wall of the ink container. As a result, the charge on the surface of the inner wall shifts to the negative side, and the electrostatic repulsion between the inner wall and the dye improves, leading to more stable dispersion. Furthermore, because these anionic surfactants have an ethylene oxide structure, they have high compatibility with components contained in the ink composition, resulting in a greater effect in improving dispersion stability.

[0012] Based on these findings, it is presumed that this embodiment can provide an ink composition in which the generation of foreign matter as aggregates caused by the materials within the ink container is effectively prevented. However, the reasons are not limited to this.

[0013] Next, we will explain each component contained in the ink composition.

[0014] 1.1.Sublimable dye The ink composition of this embodiment contains a sublimation dye. The sublimation dye includes one or more selected from the group consisting of CI Disperse Orange 25, CI Disperse Orange 80, CI Disperse Brown 27, CI Solvent Orange 60, CI Solvent Violet 13, and CI Disperse Violet 28. In this specification, "sublimation dye" refers to a dye that has the property of sublimating when heated. The sublimation dye may be used alone or in combination of two or more types.

[0015] Among these sublimable dyes, C.I. Disperse Orange 25 is more likely to generate foreign substances as aggregates. However, according to the ink composition of the present embodiment, even if it contains C.I. Disperse Orange 25 which is likely to generate such foreign substances, the generation of foreign substances can be effectively prevented.

[0016] Since an ink composition can be obtained in which the generation of foreign substances is more effectively prevented in the ink storage body, the total content of C.I. Disperse Orange 25, C.I. Disperse Orange 80, C.I. Disperse Brown 27, C.I. Solvent Orange 60, C.I. Solvent Violet 13, and C.I. Disperse Violet 28 is preferably 0.05% by mass or more and 30% by mass or less, more preferably 0.1% by mass or more and 20% by mass or less, still more preferably 0.5% by mass or more and 10% by mass or less, and particularly preferably 1.0% by mass or more and 5.0% by mass or less with respect to the total amount of the ink composition.

[0017] 1.2. Anionic dispersant The ink composition of the present embodiment contains an anionic dispersant. The anionic dispersant is not particularly limited as long as it ionizes to become an anion. Also, in this specification, the anionic dispersant is different from an anionic surfactant. The anionic dispersant is preferably added during the preparation of the dye dispersion liquid of the sublimable dye. The anionic dispersant may be used alone or in combination of two or more.

[0018] Since the effect of improving the dispersion stability of the dye is greater and the generation of foreign substances in the ink storage body can be more effectively prevented, the weight average molecular weight Mw of the anionic dispersant is preferably 1000 or more and 20000 or less, more preferably 2000 or more and 10000 or less, and still more preferably 3000 or more and 5000 or less. In this specification, the weight average molecular weight refers to a value in terms of polystyrene measured by gel permeation chromatography, so-called GPC.

[0019] As the anionic dispersant, a compound having a sulfo group or its salt and an aromatic ring in its structure is preferable, and a compound having a salt of a sulfo group and an aromatic ring is more preferable. By using such an anionic dispersant, the effect of improving the dispersion stability of the dye is greater, and the generation of foreign substances in the ink storage body can be more effectively prevented.

[0020] As the anionic dispersant, it is preferable to contain one or more selected from the group consisting of a compound represented by the following formula (2), a sodium salt of a naphthalenesulfonic acid formalin condensate, and a sodium salt of ligninsulfonic acid. These anionic dispersants tend to have an even greater effect of improving the dispersion stability of the dye and can more effectively prevent the generation of foreign substances in the ink storage body.

[0021]

Chemical formula

[0022] In formula (2), R2 represents a monovalent hydrocarbon group having 1 to 4 carbon atoms, and n represents an integer of 1 or more.

[0023] Examples of the monovalent hydrocarbon group having 1 to 4 carbon atoms in R2 include linear or branched alkyl groups such as methyl group, ethyl group, n-propyl group, iso-propyl group, n-butyl group, iso-butyl group, and 1,1-dimethylpropyl group; linear or branched alkenyl groups such as vinyl group and allyl group. Among them, since the effect of improving the dispersion stability of the dye is even greater and the generation of foreign substances in the ink storage body can be more effectively prevented, as R2, an n-butyl group and an iso-butyl group are preferable, and an n-butyl group is more preferable. Since the effect of improving the dispersion stability of the dye is greater and the generation of foreign substances in the ink storage body can be more effectively prevented, as the compound represented by formula (2), a sodium salt of n-butylnaphthalenesulfonic acid formalin condensate is preferable.

[0024] n is preferably an integer between 1 and 50, more preferably an integer between 1 and 30, and even more preferably an integer between 1 and 20.

[0025] Since the effect of improving the dispersion stability of the dye is even greater and the generation of foreign matter within the ink container tends to be even more effective, the content of the anionic dispersant is preferably 0.05% by mass or more and 30% by mass or less, more preferably 0.1% by mass or more and 20% by mass or less, even more preferably 0.5% by mass or more and 10% by mass or less, and particularly preferably 1.0% by mass or more and 5.0% by mass or less, based on the total amount of the ink composition.

[0026] 1.3. Anionic surfactants The ink composition of this embodiment contains an anionic surfactant. The anionic surfactant includes one or more selected from the group consisting of polyoxyethylene alkyl ether sulfate, polyoxyethylene alkenyl ether sulfate, polyoxyethylene aryl ether sulfate, and polyoxyethylene alkyl ether phosphate. These anionic dispersants readily adsorb to the sublimable dye and the inner wall of the ink container, and have high compatibility with the components contained in the ink composition. As a result, they have a significant effect in improving the dispersion stability of the dye and tend to effectively prevent the generation of foreign matter within the ink container. It is preferable that the anionic surfactant is added together with the dye dispersion during the preparation of the ink composition. The anionic surfactant may be used alone or in combination of two or more.

[0027] Examples of salts include alkali metal salts of Group 1 of the periodic table, such as potassium salts and sodium salts; and alkaline earth metal salts of Group 2 of the periodic table, such as calcium salts and magnesium salts. Among these, alkali metal salts of Group 1 of the periodic table are preferred, potassium salts and sodium salts are more preferred, and sodium salts are even more preferred, because they have a greater effect in improving the dispersion stability of the dye and can more effectively prevent the generation of foreign matter in the ink container.

[0028] Examples of polyoxyethylene alkyl ether sulfates include those having ethylene oxide polymerization numbers of 1 to 30 and alkyl groups with 1 to 50 carbon atoms. However, it is preferable to use polyoxyethylene alkyl ether sulfates having ethylene oxide polymerization numbers of 1 to 20 and alkyl groups with 10 to 40 carbon atoms, as this provides a greater improvement in the dispersion stability of the dye and more effectively prevents the generation of foreign matter within the ink container.

[0029] Examples of such polyoxyethylene alkyl ether sulfates include polyoxyethylene lauryl ether sulfate, which has 1 to 20 polymerization units of ethylene oxide; polyoxyethylene myristyl ether sulfate, which has 1 to 20 polymerization units of ethylene oxide; polyoxyethylene cetyl ether sulfate, which has 1 to 20 polymerization units of ethylene oxide; polyoxyethylene stearyl ether sulfate, which has 1 to 20 polymerization units of ethylene oxide; polyoxyethylene oleyl ether sulfate, which has 1 to 20 polymerization units of ethylene oxide; and polyoxyethylene alkyl ether sulfate, which has 1 to 20 polymerization units of ethylene oxide and 10 to 40 carbon atoms in the alkyl group. Polyoxyethylene alkyl ether sulfates may be used individually or in combination of two or more types.

[0030] Examples of polyoxyethylene alkenyl ether sulfates include those in which the polymerization number of ethylene oxide is 1 to 30 and the number of carbon atoms in the alkyl group is 1 to 50. However, it is preferable to use polyoxyethylene alkenyl ether sulfates in which the polymerization number of ethylene oxide is 1 to 25 and the number of carbon atoms in the alkenyl group is 10 to 40, as this provides a greater improvement in the dispersion stability of the dye and more effectively prevents the generation of foreign matter in the ink container.

[0031] Examples of such polyoxyethylene alkenyl ether sulfates include sodium polyoxyethylene oleyl ether sulfate, in which the polymerization number of ethylene oxide is between 1 and 25.

[0032] Examples of polyoxyethylene aryl ether sulfates include those having 1 to 30 polymerization units of ethylene oxide and 1 to 50 carbon atoms in the aryl group. However, it is preferable to use polyoxyethylene aryl ether sulfates having 1 to 20 polymerization units of ethylene oxide and 10 to 40 carbon atoms in the aryl group, as this provides a greater improvement in the dispersion stability of the dye and more effectively prevents the generation of foreign matter within the ink container.

[0033] Examples of such polyoxyethylene aryl ether sulfates include polyoxyethylene phenyl ether sulfate with 1 to 20 polymerization units of ethylene oxide, polyoxyethylene monostyrene-derived phenyl ether sulfate with 1 to 20 polymerization units of ethylene oxide, polyoxyethylene distyrene-derived phenyl ether sulfate with 1 to 20 polymerization units of ethylene oxide, polyoxyethylene tristyrene-derived phenyl ether sulfate with 1 to 20 polymerization units of ethylene oxide, and polyoxyethylene polycyclic phenyl ether sulfate with 1 to 20 polymerization units of ethylene oxide. Among these, polyoxyethylene tristyrene-derived phenyl ether sulfate with 15 to 16 polymerization units of ethylene oxide is preferred because it has a greater effect in improving the dispersion stability of the dye and can more effectively prevent the generation of foreign matter in the ink container. Polyoxyethylene aryl ether sulfates may be used alone or in combination of two or more types.

[0034] Examples of polyoxyethylene alkyl ether phosphates include those having 1 to 30 polymerization units of ethylene oxide and 1 to 50 carbon atoms in the aryl group. However, it is preferable to use polyoxyethylene alkyl ether phosphates having 1 to 20 polymerization units of ethylene oxide and 10 to 40 carbon atoms in the alkyl group, as this provides a greater improvement in the dispersion stability of the dye and more effectively prevents the generation of foreign matter within the ink container.

[0035] Examples of such polyoxyethylene alkyl ether phosphates include polyoxyethylene lauryl ether phosphate, which has 1 to 20 polymerization units of ethylene oxide; polyoxyethylene myristyl ether phosphate, which has 1 to 20 polymerization units of ethylene oxide; polyoxyethylene cetyl ether phosphate, which has 1 to 20 polymerization units of ethylene oxide; polyoxyethylene stearyl ether phosphate, which has 1 to 20 polymerization units of ethylene oxide; polyoxyethylene oleyl ether phosphate, which has 1 to 20 polymerization units of ethylene oxide; and polyoxyethylene alkyl ether phosphate, which has 5 to 15 polymerization units of ethylene oxide and 10 to 20 carbon atoms in the alkyl group. Among these, polyoxyethylene alkyl ether phosphate, which has 10 polymerization units of ethylene oxide and 12 to 15 carbon atoms in the alkyl group, is preferred because it has a greater effect in improving the dispersion stability of the dye and can more effectively prevent the generation of foreign matter in the ink container. Polyoxyethylene alkyl ether phosphates may be used alone or in combination of two or more types.

[0036] The anionic surfactant more preferably contains a compound represented by the following formula (1). The compound represented by formula (1) is more readily adsorbed to the sublimable dye and the inner wall of the ink container, and has higher compatibility with the components contained in the ink composition. As a result, it has a greater effect in improving the dispersion stability of the dye and tends to more effectively prevent the generation of foreign matter within the ink container.

[0037] R1O(CH2CH2O) m SO3 - M + ...(1)

[0038] In formula (1), R1 represents an alkyl group having 10 to 50 carbon atoms, an alkenyl group having 10 to 50 carbon atoms, or an aryl group having 10 to 50 carbon atoms. + represents an alkali metal ion. m represents the polymerization number of ethylene oxide, and is an integer between 1 and 30.

[0039] Preferably, the alkyl group in R1 has 10 to 50 carbon atoms and is a linear or branched alkyl group with 11 to 40 carbon atoms.

[0040] Examples of such alkyl groups include decyl, isodecyl, dodecyl, isododecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl, octadecyl, nonadecyl, linoleyl, linolenyl, phytyl, myricyl, undecyl, oleyl, lauryl, myristyl, cetyl, stearyl, butyloctyl, eicosyl, behenyl, myricyl, and catetil groups. Among these, the lauryl group is preferred because it provides a greater improvement in the dispersion stability of the dye and more effectively prevents the generation of foreign matter within the ink container.

[0041] The alkenyl group in R1 having 10 to 50 carbon atoms is preferably a linear or branched alkenyl group having 11 to 40 carbon atoms.

[0042] Examples of such alkenyl groups include the decenyl group, undecenyl group, dodecenyl group, tetradecenyl group, octadecenyl group, oleyl group, linoleyl group, cyclopentenyl group, cyclohexenyl group, methylcyclopentenyl group, and methylcyclohexenyl group. Among these, the oleyl group is preferred because it provides a greater improvement in the dispersion stability of the dye and more effectively prevents the generation of foreign matter within the ink container.

[0043] The aryl group in R1 having 10 to 50 carbon atoms is preferably an aryl group having 11 to 40 carbon atoms, and more preferably an aryl group having 13 to 20 carbon atoms.

[0044] Examples of such aryl groups include naphthalene, biphenyl, terphenyl, phenanthryl, anthracenyl, isopropylphenyl, butylphenyl, t-butylphenyl, di-t-butylphenyl, monostyrene-modified phenyl, disstyrene-modified phenyl, tristyrene-modified phenyl, tetrastylated phenyl, pentastylated phenyl, monostyrene-modified naphthalene, disstyrene-modified naphthalene, tristyrene-modified naphthalene, tetrastylated naphthalene, pentastylated naphthalene, and polycyclic phenyl groups. Among these, the tristyrene-modified phenyl group is preferred because it provides a greater improvement in the dispersion stability of the dye and more effectively prevents the generation of foreign matter within the ink container.

[0045] Because it has a greater effect in improving the dispersion stability of dyes and can more effectively prevent the generation of foreign matter within the ink container, M + Potassium ions and sodium ions are preferred, with sodium ions being more preferred.

[0046] m represents an integer between 1 and 20 (inclusive). Since this has a greater effect on improving the dispersion stability of the dye and can more effectively prevent the generation of foreign matter within the ink container, when R1 is an aryl group having 10 to 50 carbon atoms, m is preferably 10 to 18, and more preferably 15 to 16.

[0047] Commercially available anionic surfactants can also be used. Examples of commercially available products include Emal® 327 and 170J, and Latemul® WX (all product names, manufactured by Kao Corporation); NIKKOL® DDP-10 (product name, manufactured by Nikko Chemicals Co., Ltd.); and SM-210 (product name, manufactured by Toho Chemical Industry Co., Ltd.).

[0048] The content of polyoxyethylene alkyl ether sulfate, polyoxyethylene alkenyl ether sulfate, polyoxyethylene aryl ether sulfate, and polyoxyethylene alkyl ether phosphate is preferably 0.05% to 2.0% by mass, and more preferably 0.1% to 1.5% by mass, relative to the total amount of the ink composition. When anionic surfactants are included in the ink composition within the above range, they are more readily adsorbed to the sublimable dye and the inner wall of the ink container, and the compatibility with the components contained in the ink composition is further enhanced. This results in a greater improvement in the dispersion stability of the dye and a tendency to more effectively prevent the generation of foreign matter within the ink container. In addition, the ink composition tends to have better low foaming properties.

[0049] 1.4. Phenylazo Compounds When the sublimation dye includes one or more specific dyes selected from the group consisting of CI Disperse Orange 25, CI Disperse Orange 80, and CI Disperse Brown 27, it is preferable to further include a phenylazo compound different from the specific dye. The phenylazo compound is not particularly limited as long as it is a compound having a phenyl group and an azo group and is different from any of CI Disperse Orange 25, CI Disperse Orange 80, and CI Disperse Brown 27. The phenylazo compound may be used alone or in combination of two or more.

[0050] In this embodiment, by including a phenylazo compound in the ink composition, the ink composition tends to have a greater effect in improving the dispersion stability of the dye, and the generation of foreign matter within the ink container is more effectively prevented.

[0051] Examples of phenylazo compounds include CI Food Orange 1, 2, 3, 4, 4:1; CI Acid Orange 1, 10, 10:1, 100, 12, 125, 127, 134, 137, 14, 142, 144, 148, 154, 159, 16, 160, 164, 17, 173, 18, 19, 20, 23, 27, 28, 30, 31, 41, 5, 51, 52, 56, 60, 61, 62, 7, 72, 74, 76. ,8,86,87,88,88:1,89,9,92,97,98;CI Basic Orange 1,2,24,25,29,30,33,54,69;CI Direct Orange 17,18,75,84,85;CI Disperse Orange 1,1:1,10,127,138,149,152,157,17,18,23,25:1,3,3:1,30,31,33,36,37,41,42,44,49, 5, 50, 52, 53, 56, 57, 61, 62, 67, 68, 7, 71, 73, 76, 78, 90, 96, 97; CI Reactive Orange 1, 107, 113, 116, 118, 119, 12, 122, 123, 124, 125, 126, 13, 134, 135, 139, 14, 16, 2, 29, 3, 33, 35, 37, 38, 4, 5, 56, 64, 67, 68, 7, 70, 72, 72: 1, 82, Examples include 84, 86, 87, 91, 94, 95, 96; CI Solvent Orange 1, 102, 103, 105, 11, 110, 12, 2, 20, 3, 4, 4:1, 40:1, 41, 45, 49, 5, 54, 56, 6, 62, 7, 75, 8, 81, 9, 98, 99; CI Acid Red 6, 18, 57, 97, 106, 151, 249, 260; and CI Acid Yellow 17, 19, 42, 49, 79.

[0052] Among these, it is preferable to include one or more selected from the group consisting of CI Disperse Orange 30, CI Disperse Orange 31, and CI Disperse Orange 73. The inclusion of these phenylazo compounds in the ink composition tends to further enhance the effect of improving the dispersion stability of the dye and more effectively prevent the generation of foreign matter within the ink container.

[0053] Since an ink composition can be obtained in which the effect of improving the dispersion stability of the dye is further enhanced and the generation of foreign matter in the ink container is more effectively prevented, the content of the phenylazo compound is preferably 0.05% by mass or more and 10% by mass or less, more preferably 0.1% by mass or more and 5.0% by mass or less, and even more preferably 0.5% by mass or more and 1.0% by mass or less, based on the total amount of the ink composition.

[0054] 1.5. Water-soluble organic solvents The ink composition may contain a water-soluble organic solvent. Examples of such water-soluble organic solvents 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, and 1,6-hexanediol; glycol monoethers such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, propylene glycol monomethyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, triethylene glycol monomethyl ether, and triethylene glycol monobutyl ether; and alcohols such as methanol, ethanol, n-propyl alcohol, iso-propyl alcohol, n-butanol, 2-butanol, tert-butanol, iso-butanol, n-pentanol, 2-pentanol, 3-pentanol, and tert-pentanol. Water-soluble organic solvents may be used individually or in combination of two or more types.

[0055] Among these, glycols can function as humectants. Glycol monoethers, on the other hand, can function as penetrating agents.

[0056] From the viewpoint of achieving the effects of this embodiment more effectively and reliably, the content of the water-soluble organic solvent is preferably 5% by mass or more and 30% by mass or less in total with respect to the total amount of the ink composition.

[0057] 1.6. Surfactants The ink composition may contain surfactants other than anionic surfactants. Surfactants have the function of lowering the surface tension of the ink composition and adjusting its wettability with the recording medium. Examples of surfactants include acetylene glycol-based surfactants, silicone-based surfactants, and fluorine-based surfactants.

[0058] Examples of acetylene glycol-based surfactants include Surfinol (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, DF110D (manufactured by Nisshin Chemical Industry Co., Ltd.); Olfin (registered trademark) Trademarks include 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, SK-14; AE-3 (manufactured by Nisshin Chemical Industry Co., Ltd.); Acetylenel (registered trademark) E00, E00P, E40, E100 (manufactured by Kawaken Fine Chemical Co., Ltd.).

[0059] Examples of silicone-based surfactants include polysiloxane compounds such as polyether-modified organosiloxanes. Examples of commercially available polyether-modified organosiloxanes include BYK-306, BYK-307, BYK-333, BYK-341, BYK-345, BYK-346, BYK-348 (manufactured by BIC Chemie Japan Co., Ltd.), 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.).

[0060] Examples of fluorinated surfactants include fluorine-modified polymers. For example, BYK-340 (manufactured by Bic Chemie Japan Co., Ltd.) is one such example.

[0061] Surfactants may be used individually or in combination of two or more types.

[0062] In order to obtain an ink composition that has a greater effect in improving the dispersion stability of the dye and more effectively prevents the generation of foreign matter in the ink container, the surfactant content is preferably 0.01% to 10% by mass, more preferably 0.05% to 5.0% by mass, and even more preferably 0.1% to 1.0% by mass, relative to the total amount of the ink composition.

[0063] 1.7.Water The ink composition may contain water. Examples of suitable 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. Furthermore, water sterilized by ultraviolet irradiation or the addition of hydrogen peroxide is preferable because it can suppress the growth of mold and bacteria when the ink composition is stored for a long period of time.

[0064] The water content is preferably 30% by mass or more and 80% by mass or less of the total amount of the ink composition. By keeping the water content within the above range, an increase in the viscosity of the ink composition can be suppressed.

[0065] 1.8. Other Ingredients The ink composition may contain various additives that are commonly used in ink compositions, such as solubilizers, viscosity modifiers, pH adjusters, antioxidants, UV absorbers, oxygen absorbers, preservatives, fungicides, corrosion inhibitors, and chelating agents for capturing metal ions that affect dispersion. Additives may be used individually or in combination of two or more.

[0066] In order to obtain an ink composition that has a greater effect in improving the dispersion stability of the dye and more effectively prevents the generation of foreign matter within the ink container, it is preferable that the total amount of additives be between 0.01% by mass and 10% by mass of the total amount of the ink composition.

[0067] 1.9. Physical properties of the ink composition The viscosity of the ink composition is preferably 1.5 mPa·s to 15 mPa·s at 20°C, more preferably 1.5 mPa·s to 7 mPa·s, and even more preferably 1.5 mPa·s to 5.5 mPa·s.

[0068] From the viewpoint of ensuring appropriate wetting and spreading properties on the recording medium, the upper limit of the surface tension of the ink composition at 25°C is preferably 40 mN / m or less, more preferably 38 mN / m or less, even more preferably 35 mN / m or less, even more preferably 32 mN / m or less, and particularly preferably 30 mN / m or less. Similarly, from the same viewpoint, the lower limit of the surface tension is preferably 15 mN / m or more, more preferably 20 mN / m or more, even more preferably 25 mN / m or more, and even more preferably 27 mN / m or more. In this specification, surface tension can be measured using a surface tension meter CBVP-Z (trade name, manufactured by Kyowa Interface Science Co., Ltd.) as the surface tension when a platinum plate is wetted with the composition at room temperature and atmospheric pressure. If the surface tension of the ink composition is within the above range, the ejection stability and initial filling performance in inkjet recording can be improved.

[0069] 1.10. Method for producing an ink composition An ink composition can be prepared by mixing a sublimable dye, an anionic dispersant, an anionic surfactant, optionally a phenylazo compound, a water-soluble organic solvent, a surfactant other than the anionic surfactant, water, and other components in any order, and removing impurities and foreign substances by filtration or other means as needed. Furthermore, when manufacturing an ink composition, it is preferable to use a dye dispersion prepared in advance by mixing and dispersing a sublimable dye, an anionic dispersant, optionally a phenylazo compound, and water in any order, and removing impurities and foreign substances by filtration or other means as needed. For example, a dispersion can be obtained by mixing a sublimable dye, an anionic dispersant, optionally a phenylazo compound, and water using a mixing and dispersing machine such as a paint shaker, bead mill, or ball mill.

[0070] The mixing method for each component involves sequentially adding each component to a container equipped with a stirring device such as a mechanical stirrer or a magnetic stirrer, and then stirring and mixing them. Filtration methods include centrifugal filtration and filter filtration.

[0071] 2.Applications The ink composition effectively prevents the generation of foreign matter as aggregates caused by the materials within the ink container. Therefore, the ink composition is suitable for dyeing methods of fabrics and the like using sublimation transfer. An example of a dyeing method using sublimation transfer is a method in which printing is performed on a sheet-like transfer medium such as paper using an inkjet recording device, and then the transfer medium is placed on a recording medium such as fabric and sublimation transfer is performed by heating.

[0072] 2.1. Inkjet Recording Device An inkjet recording device is not particularly limited as long as it includes at least an ink container for containing an ink composition and a recording head connected thereto, and can eject the ink composition from the recording head to form an image on transfer paper, which is an intermediate transfer medium. In addition, either serial or line type inkjet recording devices can be used. These types of inkjet recording devices are equipped with a recording head, and while changing the relative positional relationship between the transfer paper and the recording head, droplets of the ink composition are ejected from the nozzle holes of the recording head intermittently and in a predetermined volume at predetermined timings. This allows the ink composition to adhere to the transfer paper and form a predetermined transfer image.

[0073] In general, in serial inkjet recording devices, the direction of transport of the recording medium and the direction of the reciprocating motion of the recording head intersect, and the relative positional relationship between the recording medium and the recording head is changed by the combination of the reciprocating motion of the recording head and the transport motion of the recording medium. In this case, generally, multiple nozzle holes are arranged on the recording head, and rows of nozzle holes, i.e., nozzle rows, are formed along the transport direction of the recording medium. In addition, depending on the type and number of ink compositions, multiple nozzle rows may be formed on the recording head.

[0074] Furthermore, in line-type inkjet recording devices, the recording head does not perform a reciprocating motion; instead, the relative positional relationship between the recording medium and the recording head is changed by the transport of the recording medium. In this case as well, the recording head generally has multiple nozzle holes, and a row of nozzles is formed along a direction intersecting the transport direction of the recording medium.

[0075] 2.2. Ink container In this embodiment, the term "ink container" refers to a concept encompassing containers and packaging that directly or indirectly contain an ink composition. That is, an ink container holds an ink composition. Ink containers are used to store and transport ink compositions before they are used in an inkjet recording device. Furthermore, ink containers also include those that supply the ink composition contained within the container to the recording device when the ink composition is used in the inkjet recording device. The ink composition according to this embodiment effectively prevents the generation of foreign matter as aggregates caused by the materials within the ink container. Therefore, the ink composition can be contained in the ink container with excellent storage stability.

[0076] Even if the inner wall of the ink container is made of polyolefin such as polyethylene, the ink composition according to this embodiment can effectively prevent the generation of foreign matter. Therefore, from the viewpoint of more effectively and reliably achieving the effects of this embodiment, it is preferable that the ink container comprises a container for containing the ink composition and a connecting member, and that the container is formed of a film containing polyolefin. Next, an example of such an ink container will be described using Figure 1. Figure 1 is an external view of the ink container 1.

[0077] The ink container 1 is for supplying an ink composition to an inkjet recording device. As shown in Figure 1, the ink container 1 comprises a container 11 and a connecting member 12. The container 11 contains the ink composition. The container 11 is preferably a flexible bag. The container 11 is preferably bag-shaped and formed by attaching multiple films together. In this embodiment, the container 11 is formed by overlapping two films and joining parts of their peripheral edges together, and joining parts of the peripheral edges to the joint 13 of the connecting member 12 by methods such as heat welding.

[0078] The film constituting the container 11 is made of a material having flexibility and gas barrier properties. For example, the film material can be polyethylene terephthalate, nylon, or polyolefin. Examples of polyolefins can be polyethylene or polypropylene. Polyolefin is preferred, and polyethylene is more preferred, due to its excellent flexibility. Alternatively, the film may be formed using a laminated structure in which multiple films made of these materials are laminated together. In such a laminated structure, for example, the outer layer may be made of polyethylene terephthalate or nylon with excellent impact resistance, and the inner layer may be made of a polyolefin such as polyethylene with excellent ink resistance. Furthermore, a film having a layer with aluminum or the like deposited on it may be used as one of the components of the laminated structure.

[0079] The ink capacity of the ink container 11 is preferably 1000 mL or more. If the ink capacity of the ink container 1 is within the above range, a larger amount of ink composition can be contained in the ink container 1. In this specification, "ink capacity" refers to the maximum volume of ink composition that can be contained in the ink container 1.

[0080] Specific examples of ink containers include cartridges, pouches, and tanks in inkjet recording devices.

[0081] 3. Inkjet recording method The inkjet recording method, which is a dyeing method utilizing sublimation transfer, comprises the steps of: attaching an ink composition to the recording surface of a first recording medium; placing a second recording medium on the recording surface of the first recording medium; and heating the first recording medium and the second recording medium. In other words, the sublimation transfer inkjet recording method comprises an ink application step of applying an ink composition to an intermediate transfer medium using an inkjet method; and a transfer step of heating the intermediate transfer medium to which the ink composition has been applied, with the surface to which the ink composition has been applied facing the dyeing surface of the object to be dyed, thereby transferring the disperse dye to the object to be dyed. This allows for the production of dyed materials with high productivity, and the sublimation transfer inkjet recording method can also be considered a method for manufacturing dyed materials. Each step will be described below.

[0082] 3.1. Ink application process In this process, an ink composition is applied to the recording surface of an intermediate transfer medium, which is the first recording medium, using an inkjet method. The ink composition can be ejected using an inkjet method with a droplet ejection device. An example of such a droplet ejection device is the inkjet recording device described above.

[0083] In inkjet printing, various droplet ejection methods can be used, including the piezoelectric method and a method that ejects the ink composition by heating the ink composition to generate bubbles. Among these, the piezoelectric method is preferred from the viewpoint of preventing deterioration of the ink composition.

[0084] As an intermediate transfer medium, for example, paper such as plain paper and a recording medium provided with an ink-receiving layer can be used. The above-mentioned recording medium provided with an ink-receiving layer is referred to as, for example, inkjet-specific paper and coated paper. Among these, paper provided with an ink-receiving layer containing inorganic particles such as silica is more preferable. This makes it possible to obtain an intermediate recording in which bleeding and other issues are suppressed on the recording surface during the drying process of the ink composition applied to the intermediate transfer medium. Furthermore, with such a medium, it is easier to retain the disperse dye on the surface of the recording surface, and the sublimation of the disperse dye can be carried out more efficiently in the subsequent transfer process.

[0085] In this process, multiple types of ink compositions may be used. This can, for example, broaden the range of colors that can be expressed. One of the multiple ink compositions may be the ink composition of this embodiment, or two or more may be the ink composition of this embodiment.

[0086] 3.2. Transfer Process Subsequently, the recording surface of the intermediate transfer medium to which the ink composition has been applied is heated with the material to be dyed facing it, in other words, with the second recording medium placed on the recording surface of the first recording medium, thereby transferring the disperse dyes constituting the ink composition to the material to be dyed. This results in a dyed material to which the disperse dyes have been transferred.

[0087] In this process, the intermediate transfer medium to which the ink composition has been applied should be heated while facing the object to be dyed. In this process, it is more preferable to heat the intermediate transfer medium and the object to be dyed in close contact. This allows, for example, a clearer image to be recorded on the second recording medium, i.e., dyed.

[0088] Suitable materials to be dyed include, for example, fabrics such as hydrophobic fiber cloths, and sheet-like materials such as resin films and plastic films. However, materials with three-dimensional shapes other than sheets, such as spherical and rectangular parallelepiped shapes, may also be used.

[0089] Furthermore, in addition to materials composed of resins and plastics, glass, metals, and ceramics coated with hydrophobic resins may also be used as materials to be dyed. Examples of fibers that make up the fabric to be dyed include polyester fibers, nylon fibers, triacetate fibers, diacetate fibers, polyamide fibers, and blends using two or more of these fibers. Blends of these with regenerated fibers such as rayon or natural fibers such as cotton, silk, and wool may also be used.

[0090] Examples of resin films and plastic films to be dyed include polyester films, polyurethane films, polycarbonate films, polyphenylene sulfide films, polyimide films, and polyamide-imide films. Such films may be laminates in which multiple layers are stacked, or they may be composed of gradient materials in which the composition of the material changes in a gradual manner.

[0091] The recording medium containing the fabric may be the fabric itself, but it is preferable that the fabric has been pre-treated with a pre-treatment solution containing resin particles. Pre-treatment of the fabric tends to result in a recording material with superior frictional resistance. [Examples]

[0092] The present invention will be described more specifically below using examples and comparative examples. The present invention is not limited in any way by the following examples.

[0093] 1. Preparation of inkjet ink composition 1.1. Preparation of dye dispersions 1-25 Each component was placed in a mixing tank to obtain the compositions shown in Tables 1 and 2, and dispersed using 0.3 mm zirconia beads in a paint shaker to obtain dye dispersions 1 to 25, respectively. The values ​​for each component in Tables 1 and 2 represent mass percent.

[0094] Furthermore, the components shown in Tables 1 and 2 are as follows: [Sublimable dye] • Disperse Orange 25…CI Disperse Orange 25 (commercial product) • Disperse Orange 80…CI Disperse Orange 80 (commercial product) • Disperse Brown 27…CI Disperse Brown 27 (commercial product) • Solvent Orange 60…CI Solvent Orange 60 (commercial product) • Solvent Violet 13…CI Solvent Violet 13 (commercially available product) • Disperse Violet 28…CI Disperse Violet 28 (commercial product) • Disperse Yellow 54…CI Disperse Yellow 54 (commercial product)

[0095] [Anionic dispersants] Naphthalene sulfonate formalin condensate sodium... Naphthalene sulfonate formalin condensate sodium • n-Butylnaphthalenesulfonic acid formalin condensate Na...Butylnaphthalenesulfonic acid formalin condensate sodium, the compound represented by formula (2) above. Sodium lignin sulfonate

[0096] [Phenylazo compounds] • Disperse Orange 30…CI Disperse Orange 30 (commercial product) • Disperse Orange 31…CI Disperse Orange 31 (commercial product) • Disperse Orange 73…CI Disperse Orange 73 (commercial product)

[0097] [Table 1]

[0098] [Table 2]

[0099] 1.2. Preparation of Inks 1-25 (Examples 1-20, Comparative Examples 1-4, and Reference Example 1) Each component was placed in a mixing tank to achieve the compositions shown in Tables 3 and 4, and the mixture was stirred with a stirrer for 2 hours. The mixture was then filtered through a 1 μm pore size membrane filter to obtain ink compositions 1 to 25. The values ​​for each component in Tables 3 and 4 represent mass percent.

[0100] Furthermore, the components shown in Tables 3 and 4 are as follows:

[0101] [Disperse dye] Each of the dye dispersions 1 to 25 obtained above was used. In Tables 3 and 4, the numbers in "Blended Dye Dispersion" correspond to each of the dye dispersions 1 to 25 obtained above. "Blended Amount" indicates the amount of dye dispersion blended into the ink composition.

[0102] [Water-soluble organic solvents] Glycerin Propylene glycol

[0103] [Silicone-based surfactants] • BYK-348…BYK(registered trademark)-348 (product name, manufactured by BYK Chemie Japan Co., Ltd.)

[0104] [Anionic surfactants] • Emal 327…Emal (registered trademark) 327 (product name, sodium polyoxyethylene alkyl ether sulfate, number of carbon atoms in alkyl group: 12, number of polymerization units of ethylene oxide: 3, active ingredient 27%, Kao Corporation) • Emal 170J…Emal (registered trademark) 170J (product name, sodium polyoxyethylene alkyl ether sulfate, number of carbon atoms in the alkyl group: 12, polymerization number of ethylene oxide: 1, active ingredient 70%, manufactured by Kao Corporation) • Latemul WX…Latemul (registered trademark) WX (product name, sodium polyoxyethylene alkenyl ether sulfate, alkyl group carbon number: 18-38, ethylene oxide polymerization number: 1-23, active ingredient 26%, manufactured by Kao Corporation) • NIKKOL DDP-10…NIKKOL (registered trademark) DDP-10 (product name, sodium polyoxyethylene alkyl ether phosphate, number of carbon atoms in alkyl group: 12-15, polymerization number of ethylene oxide: 10, 100% active ingredient, manufactured by Nikko Chemicals Co., Ltd.) • SM-210…SM-210 (Product name, polyoxyethylene tristyrene-modified phenyl ether sulfate, polymerization number of ethylene oxide: 15-16, 100% active ingredient, manufactured by Toho Chemical Industry Co., Ltd.) • NIKKOL SCS…NIKKOL® SCS (Trade name, sodium cetyl sulfate, number of carbon atoms in alkyl group: 16, polymerization number of ethylene oxide: 0, 100% active ingredient, manufactured by Nikko Chemicals Co., Ltd.)

[0105] [Nonionic surfactants] • B65-250… Union (registered trademark) B65-250 (product name, polyoxyethylene alkyl ether, number of carbon atoms in alkyl group: 22, number of polymerization units of ethylene oxide: 25, 100% active ingredient, manufactured by Shin Nippon Rika Co., Ltd.)

[0106] [Table 3]

[0107] [Table 4]

[0108] 2. Evaluation Method 2.1. Occurrence of foreign matter 80g of each of the inks 1-25 obtained above was sealed into an ink pack (ink capacity: 200mL) with a polyethylene inner wall material. Then, the ink pack was left in a 60°C environment for 5 days with the inner walls tightly sealed. The contact area of ​​the inner walls of the ink pack was 50cm². 2 That's what I decided. After standing, each of inks 1-25 was filtered through a 10 μm diameter metal mesh filter. The number of solid particles remaining on the metal mesh filter per 1 mm square was counted, and the amount of foreign matter generated was evaluated according to the following evaluation criteria. A higher amount of foreign matter indicates lower dispersion stability. The results are shown in Tables 5 and 6. (Evaluation Criteria) A: The number of solid particles per square millimeter was less than 5. B: The number of solid particles per 1mm square was between 5 and 30. C: The number of solid particles per 1mm square was 30 or more.

[0109] 2.2. Foaming property 30g each of inks 1-25 obtained above was placed in a 110mL Labolan screw-cap vial (manufactured by AS ONE Corporation), and allowed to stand until there was no bubble layer on the surface of the ink. The vial was shaken 30 times over 10 seconds, and then placed on a horizontal surface. The height of the bubbles on the surface of the liquid immediately after placement was measured, and the foaming ability was evaluated according to the following evaluation criteria. The evaluation results are shown in Tables 5 and 6. (Evaluation Criteria) A: Less than 20mm B: 20mm or more and less than 30mm C:30mm or more

[0110] [Table 5]

[0111] [Table 6]

[0112] As shown in Tables 5 and 6, it was found that the ink composition of this embodiment can be used to obtain an ink composition that effectively prevents the generation of foreign matter.

[0113] From the comparison between Example 1 and Examples 2-4, between Example 14 and Example 15, and between Example 16 and Example 17, it was found that including a phenylazo compound in the ink composition resulted in a greater improvement in the dispersion stability of the dye and a more effective prevention of the generation of foreign matter within the ink container.

[0114] From a comparison of Example 4 with Example 7 and Comparative Example 2, it was found that an ink composition that effectively prevents the generation of foreign matter can be obtained by having an anionic surfactant content of 0.05% to 2.0% by mass relative to the total amount of the ink composition. Furthermore, it was found that the ink composition tends to have superior low foaming properties. [Explanation of symbols]

[0115] 1...Ink container, 11...Container, 12...Connecting member, 13...Joint.

Claims

1. It contains a sublimable dye, an anionic dispersant, and an anionic surfactant. The sublimable dye comprises one or more selected from the group consisting of C.I. Disperse Orange 25, C.I. Disperse Orange 80, C.I. Disperse Brown 27, C.I. Solvent Orange 60, C.I. Solvent Violet 13, and C.I. Disperse Violet 28. An inkjet ink composition comprising one or more anionic surfactants selected from the group consisting of polyoxyethylene aryl ether sulfates and polyoxyethylene alkyl ether phosphates.

2. The inkjet ink composition according to claim 1, wherein the total content of the polyoxyethylene aryl ether sulfate and the polyoxyethylene alkyl ether phosphate is 0.05% by mass or more and 2.0% by mass or less with respect to the total amount of the ink composition.

3. The inkjet ink composition according to claim 1 or 2, wherein the anionic surfactant comprises a compound represented by the following formula (1). R 1 O(CH 2 CH 2 O) m SO 3 - M + ・・・(1) (In formula (1), R 1 represents an alkyl group having 10 to 50 carbon atoms, an alkenyl group having 10 to 50 carbon atoms, or an aryl group having 10 to 50 carbon atoms, M + represents an alkali metal ion, and m represents an integer of 1 or more and 30 or less.).

4. The inkjet ink composition according to any one of claims 1 to 3, wherein the anionic dispersant comprises one or more selected from the group consisting of a compound represented by the following formula (2), a sodium salt of naphthalene sulfonic acid formalin condensate, and a sodium salt of lignin sulfonic acid. 【Chemistry 1】 (In formula (2), R2 represents a monovalent hydrocarbon group having 1 to 4 carbon atoms, and n represents an integer of 1 or more.)

5. The inkjet ink composition according to any one of claims 1 to 4, wherein the sublimable dye includes one or more selected from the group consisting of C.I. Disperse Orange 25, C.I. Disperse Orange 80, and C.I. Disperse Brown 27, and further comprises a phenylazo compound different from any of C.I. Disperse Orange 25, C.I. Disperse Orange 80, and C.I. Disperse Brown 27.

6. The inkjet ink composition according to claim 5, wherein the phenylazo compound comprises one or more selected from the group consisting of C.I. Disperse Orange 30, C.I. Disperse Orange 31, and C.I. Disperse Orange 73.

7. An ink container comprising an inkjet ink composition according to any one of claims 1 to 6.

8. The system comprises a container for containing the ink composition and a connecting member, The ink container according to claim 7, wherein the container is formed of a film containing polyolefin.

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