Inkjet ink set for sublimation transfer, and ink jet recording method

Abstract

To provide an ink set of variable density black inks excellent in granularity, and association between colors by a combination of variable density black inks excellent in storage stability, and sedimentation resistance.SOLUTION: An inkjet ink set for sublimation transfer includes: a first black ink containing water, a water-soluble organic solvent, C.I. disperse blue 360, C.I. disperse orange 25, and C.I. solvent orange 60; and a second black ink containing water, a water-soluble organic solvent, C.I. disperse blue 360, C.I. disperse orange 25, and C.I. solvent orange 60, wherein the total content X of color materials contained in the first black ink is 4.0 mass% or more and less than 8.0 mass% to the total amount of the first black ink, the total content Y of color materials contained in the second black ink is more than 0.2 mass% and less than 4.0 mass% to the total amount of the second black ink, and a ratio (X / Y) of the total content X to the total content Y is 20 or less.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a sublimation transfer inkjet ink set and an inkjet recording method. [Background technology]

[0002] The inkjet recording method is capable of recording high-resolution images using a relatively simple device, and has been rapidly developing in various fields. For example, Patent Document 1 describes a sublimation transfer inkjet black ink composition containing water, a water-soluble organic solvent, CI Disperse Blue 360, and two or more disperse dyes that have a reflectance of less than 0.1 in the wavelength range of 380 nm or more and 520 nm or less on a dyed material. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2016-132757 Summary of the Invention [Problem to be solved by the invention]

[0004] Various studies have been conducted on the image quality of the resulting recorded matter. In particular, when using dark black ink, graininess is easily observed, and the color connection between areas formed with light color ink and areas formed with dark color ink tends to be poor. Note that "graininess" refers to the degree of roughness of the entire image. For example, if the ink dots (particles) formed on the medium are too large, the individual particles will stand out, giving the image a rough impression. Furthermore, there is also the problem that light black inks tend to have poor storage stability, while dark black inks tend to have poor sedimentation resistance. For this reason, there is a demand for an ink set of dark and light black inks that is excellent in graininess and color continuity, and that also has excellent storage stability and sedimentation properties. [Means for solving the problem]

[0005] The sublimation transfer inkjet ink set of the present invention comprises a first black ink containing water, a water-soluble organic solvent, CI Disperse Blue 360, CI Disperse Orange 25, and CI Solvent Orange 60, and a second black ink containing water, a water-soluble organic solvent, CI Disperse Blue 360, CI Disperse Orange 25, and CI Solvent Orange 60, wherein the total content X of coloring materials contained in the first black ink is 4.0% by mass or more and less than 8.0% by mass with respect to the total amount of the first black ink, the total content Y of coloring materials contained in the second black ink is more than 0.2% by mass and less than 4.0% by mass with respect to the total amount of the second black ink, and the ratio (X / Y) of the total content X to the total content Y is 20 or less.

[0006] The inkjet recording method of the present invention is an inkjet recording method that uses the sublimation transfer inkjet ink set of this embodiment, and includes a first ejection step of ejecting a first black ink and a second ejection step of ejecting a second black ink. [Brief explanation of the drawings]

[0007] [Figure 1] Data from the examples are shown below. [Figure 2] Data from the examples are shown below. [Figure 3] Data from the examples are shown below. [Figure 4] Data from the examples are shown below. [Figure 5] Data from the examples are shown below. [Figure 6] Data from the examples are shown below. [Figure 7] Data from the examples are shown below. DETAILED DESCRIPTION OF THE INVENTION

[0008] Below, we will explain in detail an embodiment of the present invention (hereinafter referred to as the "present embodiment"), referring to the drawings as necessary, but the present invention is not limited to this and various modifications are possible within the scope of the gist of the present invention.

[0009] 1. Sublimation inkjet ink set The sublimation transfer inkjet ink set of this embodiment comprises: a first black ink containing water, a water-soluble organic solvent, CI Disperse Blue 360, CI Disperse Orange 25, and CI Solvent Orange 60; a second black ink containing water, a water-soluble organic solvent, CI Disperse Blue 360, CI Disperse Orange 25, and CI Solvent Orange 60; the total content X of coloring materials contained in the first black ink is 4.0% by mass or more and less than 8.0% by mass with respect to the total amount of the first black ink; the total content Y of coloring materials contained in the second black ink is more than 0.2% by mass and less than 4.0% by mass with respect to the total amount of the second black ink; The ratio (X / Y) of the total content X to the total content Y is 20 or less.

[0010] The sublimation transfer inkjet ink set of this embodiment, due to the combination of dark and light inks described above, is less likely to produce graininess and has excellent color continuity, and also has excellent storage stability and sedimentation resistance. As mentioned above, in the past, when dark black ink was used, graininess was likely to occur, and the color continuity between areas formed using light color ink and areas formed using dark color ink was poor. In contrast, the sublimation transfer inkjet ink set of this embodiment uses a combination of dark inks containing predetermined colorants and light inks containing predetermined colorants. Furthermore, the type and amount of colorant in each ink is specified to ensure a color reproduction range, and the content ratio of the colorant in the dark ink to the colorant in the light ink is adjusted to fall within a predetermined range. As a result, the sublimation transfer inkjet ink set of this embodiment is less prone to graininess, has excellent color continuity, and also exhibits excellent storage stability and sedimentation resistance.

[0011] 1.1.1st black ink The first black ink contains water, a water-soluble organic solvent, CI Disperse Blue 360, CI Disperse Orange 25, and CI Solvent Orange 60.

[0012] 1.1.1.Colorants The first black ink contains at least CI Disperse Blue 360, CI Disperse Orange 25, and CI Solvent Orange 60 as colorants. The total content X of the coloring materials contained in the first black ink is equal to or greater than 4.0 mass % and less than 8.0 mass % with respect to the total amount of the first black ink. When the total content X of the coloring materials contained in the first black ink is 4.0 mass % or more relative to the total amount of the first black ink, graininess is less likely to occur and excellent color continuity is achieved. When the total content X of coloring materials contained in the first black ink is less than 8.0% by mass with respect to the total amount of the first black ink, graininess is less likely to occur, the color connection is excellent, and sedimentation resistance is excellent.

[0013] From the above viewpoints, the total content X of coloring materials contained in the first black ink is preferably 4.5% by mass or more and 7.5% by mass or less, and more preferably 5.0% by mass or more and 7.0% by mass or less, relative to the total amount of the first black ink. When the total content X of coloring materials contained in the first black ink is within this range, the storage stability and sedimentation resistance are superior. The first black ink in this embodiment may be a dark black ink because it contains a relatively high concentration of colorant.

[0014] The first black ink may contain color materials other than those mentioned above. Other coloring materials include disperse dyes. The disperse dye is not particularly limited, but examples thereof include the following:

[0015] The yellow disperse dye is not particularly limited, but examples thereof include CI Disperse Yellow 3, 4, 5, 7, 9, 13, 23, 24, 30, 33, 34, 42, 44, 49, 50, 51, 54, 56, 58, 60, 63, 64, 66, 68, 71, 74, 76, 79, 82, 83, 85, 86, 88, 90, 91, 93, 98, 99, 100, and 104. , 108, 114, 116, 118, 119, 122, 124, 126, 135, 140, 141, 149, 160, 162, 163, 164, 165, 179, 180, 182, 183, 184, 186, 192, 198, 199, 202, 204, 210, 211, 215, 216, 218, 224, 227, 231, 232, etc.

[0016] The orange disperse dye is not particularly limited, but examples thereof include CI Disperse Orange 1, 3, 5, 7, 11, 13, 17, 20, 21, 29, 30, 31, 32, 33, 37, 38, 42, 43, 44, 45, 46, 47, 48, 49, 50, 53, 54, 55, 56, 57, 58, 59, 61, 66, 71, 73, 76, 78, 80, 89, 90, 91, 93, 96, 97, 119, 127, 130, 139, and 142.

[0017] The red disperse dye is not particularly limited, but examples thereof include CI Disperse Red 1, 4, 5, 7, 11, 12, 13, 15, 17, 27, 43, 44, 50, 52, 53, 54, 55, 56, 58, 59, 60, 65, 72, 73, 74, 75, 76, 78, 81, 82, 86, 88, 90, 91, 92, 93, 96, 103, 105, 106, 107, 108, 110, 111, 113, 117, 118, 121, 122, 126, 127, 128, 131, 132, 134, 135, 137, 138, 139, 140, 141, 142, 143, 144, 145, 146, 147, 148, 149, 150, 151, 152, 153, 154, 155, 156, 157, 158, 159, 200, 201, 202, 203, 204, 205, 206, 207, 208, 209, 210, 211, 212, 213, 214, 215, 216, 217, 218, 219, 220, 221, 222, 223, 224, 225, 226, 43, 145, 146, 151, 152, 153, 154, 157, 159, 164, 167, 169, 177, 179, 181, 183, 184, 185, 188, 189, 190, 191, 192, 200, 201, 202, 203, 205, 206, 207, 210, 221, 224, 225, 227, 229, 239, 240, 257, 258, 266, 277, 278, 279, 281, 288, 298, 302, 303, 310, 311, 312, 320, 324, 328, etc.

[0018] The violet disperse dye is not particularly limited, but examples thereof include CI Disperse Violet 1, 4, 8, 23, 26, 27, 28, 31, 33, 35, 36, 38, 40, 43, 46, 48, 50, 51, 52, 56, 57, 59, 61, 63, 69, and 77.

[0019] The green disperse dye is not particularly limited, but examples thereof include CI Disperse Green 9 and the like.

[0020] The brown disperse dye is not particularly limited, but examples thereof include CI Disperse Brown 1, 2, 4, 9, 13, 19, and 27.

[0021] The blue disperse dye is not particularly limited, but examples thereof include CI Disperse Blue 3, 7, 9, 14, 16, 19, 20, 26, 27, 35, 43, 44, 54, 55, 56, 58, 60, 62, 64, 71, 72, 73, 75, 79, 81, 82, 83, 87, 91, 93, 94, 95, 96, 102, 106, 108, 112, 113, 115, 118, 120, 122, 125, 128, 130, 134, 139, 141, 142, 143, 144, 145, 146, 147, 148, 149, 150, 151, 152, 153, 154, 155, 156, 157, 158, 159, 160, 161, 162, 163, 164, 165, 166, 167, 168, 169, 170, 171, 172, 173, 174, 175, 176, 177, 178, 179, 180, 181, 182, 183, 184, 185, 186, 187, 188, 189, 190, 191, 192, 193, 194, 195, 196, 197, 198, 43, 146, 148, 149, 153, 154, 158, 165, 167, 171, 173, 174, 176, 181, 183, 185, 186, 187, 189, 197, 198, 200, 201, 205, 207, 211, 214, 224, 225, 257, 259, 266, 267, 268, 270, 284, 285, 287, 288, 291, 293, 295, 297, 301, 315, 330, 333, 359, etc.

[0022] The black disperse dye is not particularly limited, but examples thereof include CI Disperse Black 1, 3, 10, 24, and the like.

[0023] 1.1.2.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. Furthermore, by using water that has been sterilized by ultraviolet irradiation, addition of hydrogen peroxide, or the like, it is possible to prevent the growth of mold and bacteria when storing the ink for a long period of time. This tends to further improve storage stability.

[0024] The content of water relative to the total amount of the first black ink is preferably 50 to 90% by mass, more preferably 55 to 85% by mass, and even more preferably 60 to 80% by mass. By ensuring that the water content is within the above range, the viscosity of the ink can be more easily adjusted and the ink can be easily removed after ejection, resulting in superior productivity.

[0025] 1.1.3. Water-soluble organic solvents The water-soluble organic solvent is not particularly limited, but examples thereof include glycols such as ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, polypropylene glycol, propanediol, butanediol, pentanediol, and hexylene glycol; lower alkyl ethers of glycols such as ethylene glycol monomethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, and triethylene glycol monomethyl ether; glycerin, 2-pyrrolidone, N-methylpyrrolidone, etc. Among these, it is preferable to include at least one selected from the group consisting of glycerin, propylene glycol, and triethylene glycol monomethyl ether. These water-soluble organic solvents can be used alone or in combination of two or more.

[0026] The total content of the water-soluble organic solvents is preferably 5.0 to 50% by mass, more preferably 10 to 45% by mass, and even more preferably 20 to 35% by mass, relative to the total amount of the first black ink.

[0027] Dispersants The first black ink may contain a dispersant. The inclusion of a dispersant in the first black ink tends to improve the dispersion stability of the dye in the first black ink. The dispersant is not particularly limited, but examples thereof include anionic dispersants, nonionic dispersants, and polymeric dispersants.

[0028] The anionic dispersant is not particularly limited, but examples thereof include naphthalenesulfonic acid condensates such as formalin condensates of aromatic sulfonic acids, formalin condensates of β-naphthalenesulfonic acids, and formalin condensates of alkylnaphthalenesulfonic acids, and formalin condensates of creosote oil sulfonic acids.

[0029] The aromatic sulfonic acid is not particularly limited, but examples thereof include 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.

[0030] The nonionic dispersant is not particularly limited, but examples thereof include ethylene oxide adducts of phytosterol and ethylene oxide adducts of cholestanol.

[0031] The polymer dispersant is not particularly limited, but examples thereof include polyacrylic acid partial alkyl esters, polyalkylene polyamines, polyacrylates, styrene-acrylic acid copolymers, vinylnaphthalene-maleic acid copolymers, and the like.

[0032] The content of the dispersant relative to the total amount of dye contained in the first black ink is preferably 50% to 150% by mass, and more preferably 75% to 125% by mass. By keeping the content of the dispersant within this range, the dispersion stability of the dye tends to be further improved.

[0033] Surfactants The first black ink preferably contains a surfactant. The surfactant is not particularly limited, but examples thereof include acetylene glycol surfactants, anionic surfactants, and silicone surfactants.

[0034] The acetylene glycol surfactant is not particularly limited, but is preferably at least one selected from the group consisting of 2,4,7,9-tetramethyl-5-decyne-4,7-diol, alkylene oxide adducts of 2,4,7,9-tetramethyl-5-decyne-4,7-diol, and alkylene oxide adducts of 2,4-dimethyl-5-decyne-4-ol and alkylene oxide adducts of 2,4-dimethyl-5-decyne-4-ol. Commercially available acetylene glycol surfactants are not particularly limited, but examples thereof include E series such as Olfin 104 series and Olfin E1010 (trade names manufactured by Air Products Japan, Inc.), Surfynol 465 and Surfynol 61 (trade names manufactured by Nissin Chemical Industry Co., Ltd.), and the like. The acetylene glycol surfactants may be used alone or in combination of two or more.

[0035] Examples of anionic surfactants include, but are not limited to, alkyl sulfocarboxylates, alkyl diphenyl ether disulfonates, α-olefin sulfonates, polyoxyethylene alkyl ether acetates, N-acyl amino acids and salts thereof, N-acyl methyl taurines, alkyl sulfates, polyoxyalkyl ether sulfates, alkyl sulfates, polyoxyethylene alkyl ether phosphates, rosin acid soaps, castor oil sulfates, lauryl alcohol sulfates, alkylphenol phosphates, alkyl phosphates, alkylaryl sulfonates, diethyl sulfosuccinates, diethylhexyl cyrsulfosuccinates, and dioctyl sulfosuccinates. Commercially available anionic surfactants are not particularly limited, but examples thereof include Pelex SS-H and Pelex SS-L (trade names, manufactured by Kao Corporation). One type of anionic surfactant may be used alone, or two or more types may be used in combination.

[0036] Examples of silicone surfactants include polysiloxane compounds and polyether-modified organosiloxanes. Commercially available silicone surfactants include, but are not limited to, BYK-306, BYK-307, BYK-333, BYK-341, BYK-345, BYK-346, BYK-347, BYK-348, and BYK-349 (all trade names, manufactured by BYK Japan KK), KF-351A, KF-352A, KF-353, KF-354L, KF-355A, KF-615A, KF-945, KF-640, KF-642, KF-643, KF-6020, X-22-4515, KF-6011, KF-6012, KF-6015, and KF-6017 (all trade names, manufactured by Shin-Etsu Chemical Co., Ltd.).

[0037] The content of the surfactant is preferably 0.1 to 2.5% by mass, and more preferably 0.1 to 1.0% by mass, relative to the total amount of the first black ink. If the content of the surfactant is within this range, the dispersion stability of the dye tends to be further improved.

[0038] 1.1.6.Other Ingredients The first black ink may contain other components in addition to the above-mentioned components. Other ingredients include dissolution aids, viscosity adjusters, pH adjusters, antioxidants, preservatives, antifungal agents, corrosion inhibitors, and chelating agents for capturing metal ions that affect dispersion.

[0039] 1.2. Second black ink The second black ink contains water, a water-soluble organic solvent, CI Disperse Blue 360, CI Disperse Orange 25, and CI Solvent Orange 60.

[0040] 1.2.1.Colorants The second black ink contains at least CI Disperse Blue 360, CI Disperse Orange 25, and CI Solvent Orange 60 as colorants. The total content Y of the coloring materials contained in the second black ink is more than 0.2 mass % and less than 4.0 mass % with respect to the total amount of the second black ink. When the total content Y of coloring materials contained in the second black ink exceeds 0.2 mass % of the total amount of the second black ink, graininess is less likely to occur, the color connection is excellent, and the ink has excellent storage stability. When the total content Y of coloring materials contained in the second black ink is less than 4.0% by mass with respect to the total amount of the second black ink, graininess is less likely to occur and excellent color continuity is achieved.

[0041] From the above viewpoints, the total content Y of coloring materials contained in the second black ink is preferably 0.3% by mass or more and 3.5% by mass or less, and more preferably 0.5% by mass or more and 3.0% by mass or less, relative to the total amount of the second black ink. When the total content Y of coloring materials contained in the second black ink is within this range, the storage stability and sedimentation resistance are superior. The second black ink in this embodiment may be a light black ink because it contains a colorant of a relatively low concentration.

[0042] The second black ink may contain color materials other than those mentioned above. Other coloring materials include disperse dyes. Details of specific embodiments, preferred embodiments, etc. of the disperse dye are the same as those of specific embodiments, preferred embodiments, etc. of the disperse dye described in the above section 1.1.1. Coloring material.

[0043] 1.2.2.Water The second black ink contains water. Specific aspects, preferred aspects, content, and other details of the water in the second black ink are the same as those of the water in the first black ink.

[0044] 1.2.3. Water-soluble organic solvents The second black ink contains a water-soluble organic solvent. Specific aspects, preferred aspects, content, and other details of the water-soluble organic solvent in the second black ink are the same as those of the water in the first black ink.

[0045] Dispersants The second black ink may include a dispersant. The specific aspects, preferred aspects, content, and other details of the dispersant in the second black ink are the same as the specific aspects, preferred aspects, content, and other details of the dispersant in the first black ink.

[0046] The first black ink and / or the second black ink preferably contains a naphthalenesulfonic acid condensate.

[0047] Surfactants The second black ink preferably contains a surfactant. The specific aspects, preferred aspects, content, and other details of the dispersant in the second black ink are the same as the specific aspects, preferred aspects, content, and other details of the dispersant in the first black ink.

[0048] 1.2.6.Other Ingredients The second black ink may contain other components in addition to the above-mentioned components. Other ingredients include: The details of the specific aspects of the other components in the second black ink are the same as the details of the specific aspects of the other components of the dispersant in the first black ink.

[0049] In this embodiment, the ratio (X / Y) of the total content X to the total content Y is 20 or less. An X / Y ratio of 20 or less results in excellent color connectivity. From the above viewpoint, X / Y is preferably 15 or less, more preferably 10 or less, and even more preferably 7.0 or less. There is no particular limit to the lower limit of X / Y. X / Y is preferably more than 0, more preferably 1.0 or more, and even more preferably 2.5 or less.

[0050] The ratio (X / Y) of the total content X to the total content Y may be more than 0 and 20 or less, or may be 2.5 or more and 7.0 or less.

[0051] Furthermore, the first black ink and the second black ink preferably contain a disperse dye, and more preferably contain CI Disperse Yellow 54.

[0052] In the present embodiment, it is preferable that the first water-soluble organic solvent and the second water-soluble organic solvent each independently include at least one selected from the group consisting of glycerin, propylene glycol, and methyl triglycol, More preferably, the first water-soluble organic solvent contains glycerin, and the second water-soluble organic solvent contains at least one of propylene glycol and methyl triglycol.

[0053] the first black ink and / or the second black ink contains a first water-soluble organic solvent and a second water-soluble organic solvent different from the first water-soluble organic solvent; The SP value of the first water-soluble organic solvent is preferably greater than the SP value of the second water-soluble organic solvent.

[0054] In this specification, the SP value is a solubility parameter based on the Hansen method, and is also referred to as the Hansen SP value. The Hansen method classifies the SP value δ into three terms, and δ 2 =δ d 2 +δ p 2 +δ h 2 δ d , δ p , δ h are the solubility parameters corresponding to the dispersion force term, dipole-dipole force term, and hydrogen bond force term, respectively. The units of the SP value and Hansen SP value are (cal / cm 3 ) 1 / 2The Hansen SP value may be a value derived using the calculation software Hansen-Solubility HSPiP.

[0055] Examples of the SP values of water-soluble organic solvents include glycerin (SP value: 16.7), propylene glycol (SP value: 14.2), dipropylene glycol monomethyl ether (SP value: 10.1), dipropylene glycol dimethyl ether (SP value: 8.4), triethylene glycol monomethyl ether (SP value: 10.7), triethylene glycol monobutyl ether (SP value: 10.0), ethylene glycol diethyl ether (SP value: 8.3), ethylene glycol monoethyl ether (SP value: 10.5), ethylene glycol Examples include ethanol monophenyl ether (SP value: 11.5), ethylene glycol monobutyl ether (SP value: 9.5), ethylene glycol monobenzyl ether (SP value: 10.9), ethylene glycol monomethyl ether (SP value: 11.4), diethylene glycol monoethyl ether (SP value: 10.2), diethylene glycol monobutyl ether (SP value: 10.0), triethylene glycol monomethyl ether (SP value: 10.5), and propylene glycol monomethyl ether (SP value: 10.0).

[0056] When the water-soluble organic solvent contains multiple solvents, the SP value is measured by the following method. The SP value of each ink is measured by turbidity point titration using water / acetone mixed solutions with different mixing ratios.

[0057] 2. Inkjet recording method The inkjet recording method of this embodiment is an inkjet recording method that uses the sublimation transfer inkjet ink set of this embodiment, and includes a first ejection step of ejecting a first black ink and a second ejection step of ejecting a second black ink.

[0058] 2.1. First discharge process, second discharge process The first and second ejection steps are steps of ejecting the first and second black inks by an inkjet method, and preferably are steps of ejecting the first and second black inks by an inkjet method and causing them to adhere to an intermediate transfer medium. The first black ink and the second black ink can be ejected by the inkjet method using a known inkjet recording device. Examples of ejection methods that can be used include a piezo method and a method in which ink is ejected by bubbles generated by heating the ink. Among these, the piezo method is preferred from the viewpoint of preventing deterioration of the ink composition.

[0059] 2.1.1. Intermediate Transfer Medium The intermediate transfer medium is not particularly limited, and examples thereof include paper such as plain paper, and recording media provided with an ink-receiving layer (also known as inkjet paper, coated paper, etc.). Among these, paper provided with an ink-receiving layer made of inorganic fine particles such as silica is preferred. This makes it possible to obtain an intermediate transfer medium in which bleeding and the like are suppressed during the drying process of the ink composition attached to the intermediate transfer medium, and also tends to allow dye sublimation to proceed more smoothly in the subsequent transfer process.

[0060] 2.2.Transfer process The inkjet recording method of this embodiment preferably includes a transfer step in which the surface of the intermediate transfer medium on which the first black ink and the second black ink are adhered is heated in a state facing the dyed surface of the recording medium, thereby transferring the coloring materials contained in the first black ink and the second black ink to the recording medium.

[0061] The heating temperature in the transfer step is not particularly limited, but is preferably 160° C. or higher and 220° C. or lower, more preferably 170° C. or higher and 200° C. or lower. When the heating temperature is within the above range, the energy required for transfer can be reduced, which tends to improve the productivity of the dyed product. In addition, the color development of the resulting dyed product tends to be improved.

[0062] The heating time in this step varies depending on the heating temperature, but is preferably 30 to 90 seconds, more preferably 45 to 60 seconds. By keeping the heating time within the above range, the energy required for transfer can be reduced, and the productivity of the dyed product tends to be better. In addition, the color development of the resulting dyed product tends to be better.

[0063] 2.2.1. Recording medium The recording medium is not particularly limited, but examples thereof include fabrics (hydrophobic fiber fabrics, etc.), resin (plastic) films, paper, glass, metals, ceramics, etc. Furthermore, the recording medium may be in the form of a sheet, a sphere, a rectangular parallelepiped, or another three-dimensional shape.

[0064] When the recording medium is a fabric, the fibers constituting the fabric are not particularly limited, and examples thereof include polyester fibers, nylon fibers, triacetate fibers, diacetate fibers, polyamide fibers, and blends of 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.

[0065] Furthermore, when the recording medium is a resin (plastic) film, usable resin (plastic) films are not particularly limited, but examples thereof include polyester film, polyurethane film, polycarbonate film, polyphenylene sulfide film, polyimide film, polyamideimide film, etc. The resin (plastic) film may be a laminate in which multiple layers are stacked, or may be made of a gradient material in which the material composition changes gradually.

[0066] The inkjet ink set for sublimation transfer according to this embodiment can also be suitably used in sublimation transfer that does not use an intermediate transfer medium. [Example]

[0067] 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.

[0068] 1. Preparation of dispersion liquid The disperse dyes were CI Disperse Blue 360 (DB360), CI Disperse Orange 25 (DOR25), CI Solvent Orange 60 (SO60), and CI Disperse Yellow 54 (DY54) at a total of 15% by mass, with 15% by mass of formalin condensate of naphthalenesulfonic acid as a dispersant, and the remainder was ion-exchanged water. A 100 mL container was charged with 0.3 mm zirconia beads, dye, dispersant, and water, and the mixture was ground in a rocking mill. The mixture was then filtered to obtain a pigment dispersion. Each component was placed in a container so as to obtain the composition shown in Figs. 1 and 2, and the mixture was mixed and stirred for 1 hour using a magnetic stirrer. The mixture was then filtered through a membrane filter with a pore size of 10 µm, thereby obtaining each black inkjet textile printing ink used in the examples.

[0069] 2. Evaluation 2.1.Storage stability 10 mL of each ink composition was placed in a designated glass bottle and left to stand for 5 days in an environment of 60°C with an air-liquid interface present. The ink composition was then filtered through a metal mesh filter with a 10 μm diameter, and the number of solid particles remaining on the metal mesh filter per 1 mm square was counted and evaluated according to the following criteria. The results are shown in Figure 3. The greater the amount of foreign matter generated, the lower the storage stability. [Judgment criteria] A: The number of solid particles per 1 mm square was less than 5. B: The number of solid particles per 1 mm square was 5 or more and less than 30. C: The number of solid particles per 1 mm square was 30 or more.

[0070] 2.2. Sedimentation resistance 100 mL of each ink composition was placed in a specified glass bottle and left to stand for 5 days in a thermostatic chamber at 60°C, and then left to stand for 3 weeks in a chamber at 25°C. 5 mL of the supernatant was sampled, and the absorbance WA at the wavelength at which the maximum value was achieved and the absorbance W0 at the wavelength at which the ink composition was maximized before being left to stand were measured, and the residual rate S was calculated using the following formula. Survival rate S(%)=((Absorbance WA) / (Absorbance W0))×100 The calculated residual rate S (%) was then used to evaluate the sedimentation resistance based on the following evaluation criteria. The results are shown in Figure 3. [Judgment criteria] A: The survival rate S was over 90%. B: The residual rate S was 80% or more but less than 90%. C: The survival rate S was less than 80%.

[0071] 2.3.Graininess Using an ink set having the combination of each ink composition shown in Figure 4, an inkjet printer (product name PX-G930, manufactured by Seiko Epson Corporation) was used to print a gradation pattern ranging from 0% duty to 100% duty output at a resolution of 720 x 720 dpi on an intermediate transfer medium, TRANSJET Classic (Cham Paper Co., Ltd.). The ink-adhered side of the intermediate transfer medium was then brought into close contact with a white recording medium, fabric (100% polyester, Amina, manufactured by Toray Industries, Inc.), and in this state, heated at 200°C for 60 seconds using a heat press machine (AF-54TEN, manufactured by Itsumi Co., Ltd.) to perform sublimation transfer, thereby obtaining each dyed product. The printed surface of each sample was visually observed and the graininess was evaluated according to the following criteria. The results are shown in Figure 4. [Judgment criteria] A: No graininess was discernible when visually observed from a distance of 30 cm from the printed surface. B: Graininess was recognizable when visually observed from a distance of 30 cm from the printed surface. C: Graininess was recognizable even when visually observed from a distance of more than 30 cm from the printed surface.

[0072] 2.4. Connections between colors Using an ink set having the combination of each ink composition shown in Figures 5 and 6, an inkjet printer (product name PX-G930, manufactured by Seiko Epson Corporation) was used to record at a resolution of 720 x 720 dpi on an intermediate transfer medium, TRANSJET Classic (Cham Paper Co.), to create a pattern that combined a 10% to 100% DUTY gradation pattern of dark ink with a 10% to 100% DUTY gradation pattern of light ink. The ink-adhered side of the intermediate transfer medium was then brought into close contact with a white recording medium, a woven fabric (100% polyester, Amina, manufactured by Toray Industries, Inc.), and heated in this state at 200°C for 60 seconds using a heat press (AF-54TEN, manufactured by Itsumi), resulting in sublimation transfer and obtaining each dyed product. The resulting evaluation samples were measured using a spectrophotometer (product name "FD-7," manufactured by Konica Minolta, Inc.) under conditions of a D65 light source and a viewing angle of 2 degrees, and the a* and b* values were calculated. The calculated a* and b* values were evaluated according to the following criteria. A rating of A indicates excellent color continuity. The results are shown in Figures 5 and 6. [Judgment criteria] A: In the dark ink (a1, b1) and the light ink (a2, b2), the values of |a1-a2| and |b1-b2| were both 2 or less. B: In the dark ink (a1, b1) and the light ink (a2, b2), either one of the values |a1-a2| and |b1-b2| was greater than 2 and 5 or less. C: In the dark ink (a1, b1) and the light ink (a2, b2), either one of the values |a1-a2| and |b1-b2| was greater than 5 and 10 or less. D: In the dark ink (a1, b1) and the light ink (a2, b2), either the value of |a1-a2| or |b1-b2| was greater than 10.

[0073] FIG. 7 shows the concentration ratio (X / Y) of the coloring materials in each combination of ink compositions.

[0074] In an example using a sublimation transfer inkjet ink set comprising a first black ink containing water, a water-soluble organic solvent, CI Disperse Blue 360, CI Disperse Orange 25, and CI Solvent Orange 60, and a second black ink containing water, a water-soluble organic solvent, CI Disperse Blue 360, CI Disperse Orange 25, and CI Solvent Orange 60, the total content X of colorants contained in the first black ink was 4.0% by mass or more and less than 8.0% by mass with respect to the total amount of the first black ink, the total content Y of colorants contained in the second black ink was more than 0.2% by mass and less than 4.0% by mass with respect to the total amount of the second black ink, and the ratio (X / Y) of the total content X to the total content Y was 20 or less, the combination of dark and light black inks having excellent storage stability and sedimentation resistance made it less likely to produce graininess and had excellent color continuity.

Claims

1. a first black ink containing water, a water-soluble organic solvent, C.I. Disperse Blue 360, C.I. Disperse Orange 25, and C.I. Solvent Orange 60; a second black ink containing water, a water-soluble organic solvent, C.I. Disperse Blue 360, C.I. Disperse Orange 25, and C.I. Solvent Orange 60; a total content X of coloring materials contained in the first black ink is 4.0% by mass or more and less than 8.0% by mass with respect to the total amount of the first black ink; a total content Y of coloring materials contained in the second black ink is more than 0.2% by mass and less than 4.0% by mass with respect to the total amount of the second black ink; a ratio (X / Y) of the total content X to the total content Y is 20 or less.

2. 2. The sublimation transfer inkjet ink set according to claim 1, wherein the first black ink and the second black ink further comprise C.I. Disperse Yellow 54.

3. 2. The sublimation transfer inkjet ink set according to claim 1, wherein the ratio (X / Y) of the total content X to the total content Y is 2.5 or more and 7.0 or less.

4. 2. The sublimation transfer inkjet ink set according to claim 1, wherein a total content X of coloring materials contained in the first black ink is 5.0% by mass or more and 7.0% by mass or less with respect to the total amount of the first black ink.

5. 2. The sublimation transfer inkjet ink set according to claim 1, wherein a total content Y of coloring materials contained in the second black ink is 0.5% by mass or more and 3.0% by mass or less with respect to the total amount of the second black ink.

6. the first black ink and / or the second black ink contains a first water-soluble organic solvent and a second water-soluble organic solvent different from the first water-soluble organic solvent; The sublimation transfer inkjet ink set according to claim 1 , wherein the SP value of the first water-soluble organic solvent is greater than the SP value of the second water-soluble organic solvent.

7. the first water-soluble organic solvent includes glycerin; 7. The sublimation transfer inkjet ink set according to claim 6, wherein the second water-soluble organic solvent contains at least one of propylene glycol and methyl triglycol.

8. The sublimation transfer inkjet ink set according to claim 1 , wherein the first black ink and / or the second black ink contains a naphthalene sulfonic acid condensate.

9. An inkjet recording method using the sublimation transfer inkjet ink set according to any one of claims 1 to 8, comprising: a first ejection step of ejecting the first black ink; a second ejection step of ejecting the second black ink; An inkjet recording method comprising:

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