JP2017186429A - Ink composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ink composition that contains a disperse dye, suppresses an occurrence of a foreign matter, has excellent storage stability and discharge stability, and also has low viscosity.SOLUTION: An ink composition contains a disperse dye, a formalin condensate of an aromatic sulfonic acid, an alkali metal compound with a molecular weight of 40 or more and 400 or less, and water.SELECTED DRAWING: None

Description

  The present invention relates to an ink composition.

  The ink jet recording method is a method of recording by ejecting small ink droplets from fine nozzles and attaching them to a recording medium. This method has a feature that a high-resolution and high-quality image can be recorded at a high speed with a relatively inexpensive apparatus. In the ink jet recording method, there are a large number of consideration factors including the nature of the ink used, the stability in recording, and the quality of the obtained image, and research on not only the ink jet recording apparatus but also the ink composition to be used is active. is there. For example, there are the following studies on an ink composition using a disperse dye as a coloring material.

  In Patent Document 1, a highly sharp print image is obtained by using a specific dispersant in an ink composition comprising a disperse dye dispersed by a dispersant, a water-soluble organic solvent, a surfactant, and water. In addition, attempts have been made to prevent non-ejection even during long-time printing, to improve storage stability, and to shorten the time until small bubbles disappear.

  Further, Patent Document 2 discloses an ink for inkjet printing containing a disperse dye, a dispersant, and an aqueous liquid medium, and includes a dispersant having an anion group and counter ions being alkali metal ions and organic ammonium ions. What it contains is proposed. Patent Document 2 discloses that the ink for ink-jet printing has good dispersion stability at high temperatures and for a long period of time, and can form a printed product with high density and clearness and excellent leveling properties. There are descriptions such as having excellent discharge characteristics without deposition and heater destruction, and having stable dispersibility and discharge characteristics over a long period of time.

JP 2003-128962 A JP 08-325472 A

  In the inks described in Patent Documents 1 and 2, an attempt is made to improve the dispersibility of the disperse dye by using an ionic dispersant or an ionic surfactant. However, such a dispersant has an effect of dissolving the disperse dye in addition to the effect of enhancing the dispersibility of the disperse dye. That is, when the blending amount of the dispersant is small, the dispersibility becomes insufficient, and when the blending amount is large, the disperse dye is dissolved. Therefore, if the amount added is increased in order to improve the dispersibility of the disperse dye, foreign matter may be generated instead.

  Since the ink composition is a complex system containing many components, details of the mechanism of foreign matter generation are not always well understood at the present time, but according to the inventor's study, the amount of the dispersant is particularly large. In some cases, the disperse dye is easily dissolved, and it is presumed that this is because the dissolved disperse dye is easily recrystallized to generate foreign matters such as needle crystals when the ink is stored.

Further, since the dispersant described in the above-mentioned patent document has a large molecular weight, in order to improve the dispersibility of the disperse dye, when simply increasing the addition amount, at least suppressing the increase in the viscosity of the ink. It is necessary to consider also. For this reason, even when a dispersant is selected and the amount added is adjusted, a lot of consideration is required because it is a complicated system.

  One of the objects according to some embodiments of the present invention is to provide an ink composition that contains a disperse dye, suppresses the generation of foreign matters, has good storage stability and ejection stability, and has low viscosity. There is to do.

  SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following aspects or application examples.

One aspect of the ink composition according to the present invention is:
With disperse dyes,
A formalin condensate of an aromatic sulfonic acid;
An alkali metal compound having a molecular weight of 40 or more and 400 or less and water are included.

  In spite of containing the disperse dye, such an ink composition suppresses the generation of foreign matters, has good storage stability and ejection stability, and has a low viscosity. That is, the formalin condensate of aromatic sulfonic acid can ensure the dispersibility of the disperse dye and suppress the generation of foreign matters by not excessively increasing the dissolution of the disperse dye. Moreover, the aggregation of the disperse dye can be sufficiently reduced by increasing the concentration of alkali metal ions with the alkali metal compound. Furthermore, since the molecular weight of the alkali metal compound is 40 or more and 400 or less, the viscosity of the ink composition is not excessively increased, and can be suitably used for, for example, ink jet recording.

In the ink composition according to the present invention,
The concentration of alkali metal ions in 100 g of the ink composition may be 0.005 mol or more and 0.05 mol or less.

  According to such an ink composition, the dispersion of the disperse dye and the viscosity of the ink composition can be improved.

In the ink composition according to the present invention,
The alkali metal compound may be a sulfonate or a carboxylate.

  According to such an ink composition, alkali metal ions can be generated more efficiently.

In the ink composition according to the present invention,
The alkali metal compound may be a sodium salt.

  According to such an ink composition, sodium ions (alkali metal ions) can be generated more efficiently.

In the ink composition according to the present invention,
The organic acid salt may be at least one selected from sodium methanesulfonate, sodium acetate, sodium sulfate, and sodium benzenesulfonate.

  According to such an ink composition, the dispersion of the disperse dye and the viscosity of the ink composition can be further improved.

In the ink composition according to the present invention,
The disperse dye is C.I. I. Disper thread 60 and C.I. I. At least one type of disperse orange 25 may be used.

  In such an ink composition, C.I. I. Although the disperse thread 60 and the disperse orange 25 are used, the effects of suppressing the generation of foreign matter, good storage stability and ejection stability, and low viscosity are remarkable.

In the ink composition according to the present invention,
The content of the disperse dye in the ink composition may be 4% by mass or less.

  In such an ink composition, the concentration of the disperse dye is low (light color). As a result, the amount of the dispersing agent is relatively increased, so that the generation of the foreign matter is suppressed, but the storage is suppressed. The effects of excellent stability and ejection stability and low viscosity are remarkable.

  Several embodiments of the present invention will be described below. Embodiment described below demonstrates an example of this invention. The present invention is not limited to the following embodiments, and includes various modified embodiments that are implemented within a range that does not change the gist of the present invention. Note that not all of the configurations described below are essential configurations of the present invention.

1. Ink Composition The ink composition according to this embodiment includes a disperse dye, a formalin condensate of aromatic sulfonic acid, an alkali metal compound, and water.

1.1. Disperse dye The ink composition of this embodiment contains a disperse dye. The disperse dye is a dye suitably used for dyeing hydrophobic synthetic fibers such as polyester, nylon, and acetate, and is a compound insoluble or hardly soluble in water. The molecular weight of the disperse dye is preferably 380 or less, more preferably 350 or less. The lower limit of the molecular weight of the disperse dye is not particularly limited, but the molecular weight is preferably 270 or more. When the molecular weight of the disperse dye is 380 or less, the disperse dye has an excellent sublimation property, and therefore, the color development of the obtained recorded product tends to be more excellent.

  Although it does not restrict | limit especially as a disperse dye used for the ink composition of this embodiment, Specifically, what is illustrated below is mentioned.

  Examples of yellow disperse dyes include C.I. I. Disperse Yellow 3, 4, 5, 7, 9, 13, 23, 24, 30, 33, 34, 42, 44, 49, 50, 51, 54, 56, 58, 60, 63, 64, 66, 68 71, 74, 76, 79, 82, 83, 85, 86, 88, 90, 91, 93, 98, 99, 100, 104, 108, 114, 116, 118, 119, 122, 124, 126, 135 140, 141, 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 and the like.

Examples of the orange disperse dye include C.I. I. Disperse Orange 1, 3, 5, 7, 11, 13, 17, 20, 21, 25, 29, 30, 31, 32, 33, 37, 38, 42, 43, 44, 45, 46, 47, 48 49, 50, 53, 54, 55, 56, 57, 58, 59, 61, 66, 71, 73, 76, 78, 80, 89, 90, 91, 93,
96, 97, 119, 127, 130, 139, 142 and the like.

  Examples of red disperse dyes include C.I. I. Disperse thread 1, 4, 5, 7, 11, 12, 13, 15, 17, 27, 43, 44, 50, 52, 53, 54, 55, 56, 58, 59, 60, 65, 72, 73, 74, 75, 76, 78, 81, 82, 86, 88, 90, 91, 92, 93, 96, 103, 105, 106, 107, 108, 110, 111, 113, 117, 118, 121, 122, 126, 127, 128, 131, 132, 134, 135, 137, 143, 145, 146, 151, 152, 153, 154, 157, 159, 164, 167, 169, 177, 179, 181, 183, 184, 185, 188, 189, 190, 191, 192, 200, 201, 202, 203, 205, 206, 207, 210, 221, 224, 225, 2 7,229,239,240,257,258,277,278,279,281,288,298,302,303,310,311,312,320,324,328, and the like.

  Examples of the violet disperse dye include C.I. I. Disperse violet 1, 4, 8, 23, 26, 27, 28, 31, 33, 35, 36, 38, 40, 43, 46, 48, 50, 51, 52, 56, 57, 59, 61, 63 69, 77, and the like.

  Examples of the green disperse dye include C.I. I. Disperse Green 9 etc. are mentioned.

  Examples of brown disperse dyes include C.I. I. Disperse brown 1, 2, 4, 9, 13, 19 etc. are mentioned.

  Examples of blue disperse dyes include C.I. I. Disperse Blue 3, 7, 9, 14, 16, 19, 20, 26, 27, 35, 43, 44, 54, 55, 56, 58, 60, 62, 64, 71, 72, 73, 75, 79 81, 82, 83, 87, 91, 93, 94, 95, 96, 102, 106, 108, 112, 113, 115, 118, 120, 122, 125, 128, 130, 139, 141, 142, 143 146, 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, 267, 268, 270, 284, 285, 287, 288, 291, 293, 295, 297, 01,315,330,333,359,360, and the like.

  Examples of black disperse dyes include C.I. I. Disperse black 1, 3, 10, 24 etc. are mentioned.

Examples of commercially available disperse dyes include Oraset Yellow 8GF (trade name, manufactured by Ciba Geigy, CI Disperse Yellow 82), Eisenzot Yellow 5 (trade name, manufactured by Hodogaya Chemical Co., Ltd.) CI Disperse Yellow 3), Sumiplus Yellow HLR (trade name, manufactured by Sumitomo Chemical Co., Ltd., CI Disperse Yellow 54), Kayaset Yellow AG (trade name, Nippon Kayaku Co., Ltd.) CI Disperse Yellow 54), Dialresin Yellow H2G (trade name, manufactured by Mitsubishi Chemical Corporation, CI Disperse Yellow 160), Oil Yellow 54 (trade name, manufactured by Chuo Synthetic Chemical Co., Ltd.) CI Disperse Yellow 54), Dial Resin Red H (trade name, manufactured by Mitsubishi Chemical Corporation, CI Disper Thread 5), Mipra thread B-2 (trade name, manufactured by Sumitomo Chemical Co., Ltd., CI Disper Thread 191), Kaya Set Red B (trade name, manufactured by Nippon Kayaku Co., Ltd., CI Disper Thread 60), Filetester Violet BA (trade name, manufactured by Ciba Geigy, CI Disperse Violet 57), Plastread 8335
(Trade name, manufactured by Arimoto Chemical Industry Co., Ltd., CI Disperse Violet 17), Plast Red 8375 (trade name, manufactured by Arimoto Chemical Industry Co., Ltd., CI Disperse Thread 60), Plast Blue 8516 ( Trade name, manufactured by Arimoto Chemical Co., Ltd., CI Disperse Blue 14) and the like.

  The disperse dyes exemplified above are all insoluble or sparingly soluble in water, but the aromatic sulfonic acid formalin condensate described later functions as a dispersant, so that water can be used in a specific concentration range. Can be dispersed well. Further, the disperse dyes exemplified above are slightly different in dispersibility and solubility. That is, depending on the type of disperse dye, the preferred concentration range of the dispersant is different, and the solubility by the dispersant is also different. For example, among the above disperse dyes, C.I. I. Disper thread 60 and C.I. I. Disperse Orange 25 and the like show some solubility in the formalin condensate of aromatic sulfonic acid, and due to this property, recrystallized products (foreign matter) such as needle crystals are likely to be generated.

  Among the above disperse dyes, C.I. I. Disper thread 60 and C.I. I. When at least one type of Disperse Orange 25 is included in the ink composition of the present embodiment, the use of disperse dyes that are more likely to generate foreign matter makes it difficult for foreign matter to be generated. It will appear more prominently.

  The disperse dye may be a sublimation dye. Here, the “sublimation dye” is a dye having a property of sublimation by heating. Conventionally, dyeing | staining with respect to the fabric etc. using a sublimation transfer is performed widely. As a dyeing method using such sublimation transfer, for example, an ink jet method using an ink containing a sublimation dye on a sheet-like intermediate transfer medium such as paper (hereinafter also referred to as “sublimation transfer ink”) is used. After printing is performed, an intermediate transfer medium is superposed on a recording medium such as a fabric, and sublimation transfer is performed by heating, or an ink receiving layer of a recording medium (film product or the like) provided with a peelable ink receiving layer In addition, there is a method in which printing is performed by an ink jet method using a sublimation transfer ink, followed by heating as it is to perform sublimation diffusion dyeing on a recording medium on the lower layer side, and then peeling off the ink receiving layer.

  Although it does not specifically limit as a sublimation dye, For example, C.I. I. Disperse yellow 3, 7, 8, 23, 39, 51, 54, 60, 71, 86; C.I. I. Disperse orange 1, 1: 1, 5, 20, 25, 25: 1, 33, 56, 76; C.I. I. Disperse brown 2; C.I. I. Disperse thread 11, 50, 53, 55, 55: 1, 59, 60, 65, 70, 75, 93, 146, 158, 190, 190: 1, 207, 239, 240; I. Bad red 41; I. Disperse violet 8, 17, 23, 27, 28, 29, 36, 57; C.I. I. Disperse Blue 14, 19, 26, 26: 1, 35, 55, 56, 58, 64, 64: 1, 72, 72: 1, 81, 81: 1, 91, 95, 108, 131, 141, 145 359, 360; I. Solvent blue 36, 63, 105, 111 etc. are mentioned.

  Preferred disperse dyes in this embodiment include, for example, C.I. I. Disperse Yellow 160, 163, C.I. I. Disperse thread 60, C.I. I. Disperse Orange 25, C.I. I. Solvent Violet 13, C.I. I. Disperse violet 28, C.I. I. Disperse Blue 14, 359, C.I. I. Solvent blue 11, 36, 59, 63 etc. are mentioned.

  The disperse dyes exemplified above may be used singly or as a mixed color using two or more kinds in combination.

The total content of the disperse dye is 10% by mass or less, preferably 0.1% by mass or more and 10% by mass or less, more preferably 0.2% by mass or more and 9.% by mass with respect to 100% by mass of the ink composition. It is 0 mass% or less, More preferably, it is 0.3 mass% or more and 8.0 mass% or less.

  When the content of the disperse dye is 0.1% by mass or more, the color development (OD value) of the obtained recorded product tends to be more excellent. Moreover, when the content of the disperse dye is 10% by mass or less, the ejection stability tends to be further improved.

  Further, the content of the disperse dye may be reduced, and the ink composition of the present embodiment may be a so-called “light color ink”. When the ink composition is a light color ink, the total content of disperse dyes is 5% by mass or less, preferably 4% by mass or less, more preferably 0.1% by mass with respect to 100% by mass of the ink composition. % To 4% by mass, more preferably 0.2% to 2.0% by mass.

1.2. Formalin Condensate of Aromatic Sulfonic Acid The ink composition of this embodiment includes a formalin condensate of aromatic sulfonic acid. The formalin condensate of aromatic sulfonic acid can function as a dispersant for disperse dyes. By including the formalin condensate of aromatic sulfonic acid, the dispersion stability of the disperse dye can be improved, and the generation of foreign matters at the gas-liquid interface can be particularly suppressed. In addition, since the formalin condensate of aromatic sulfonic acid can suppress the generation of foreign matters, the storage stability of the ink composition, the long-term ejection stability of the ink composition, and the like are further improved.

  The formalin condensate of aromatic sulfonic acid is not particularly limited. For example, formalin condensate of naphthalene sulfonic acid, formalin condensate of creosote oil sulfonic acid, formalin condensate of cresol sulfonic acid, formalin condensation of phenol sulfonic acid , Formalin condensate of β-naphtholsulfonic acid, formalin condensate of methylnaphthalenesulfonic acid, formalin condensate of alkylnaphthalenesulfonic acid such as formalin condensate of butylnaphthalenesulfonic acid; formalin condensate of β-naphthalenesulfonic acid; Examples include mixtures with β-naphtholsulfonic acid formalin condensate, cresolsulfonic acid formalin condensate and 2-naphthol-6-sulfonic acid formalin condensate, and ligninsulfonic acid formalin condensate.The formalin condensate of aromatic sulfonic acid preferably contains a formalin condensate of naphthalenesulfonic acid.

  Commercial products of aromatic sulfonic acid formalin condensate include Demol N (manufactured by Kao Corporation), Demol T45 (manufactured by Kao Corporation), Demol SNB (manufactured by Kao Corporation), Labelin FM45 (Daiichi Kogyo Seiyaku Co., Ltd.) Manufactured), Labelin FD40 (Daiichi Kogyo Seiyaku Co., Ltd.), Labelin AN40 (Daiichi Kogyo Seiyaku Co., Ltd.), Labelin W40 (Daiichi Kogyo Seiyaku Co., Ltd.) and the like.

  The formalin condensate of aromatic sulfonic acid may be used alone or in combination of two or more.

  The total content of the aromatic sulfonic acid formalin condensate is 0.0 mass% or more and 3 mass% or less, preferably 0.2 mass% or more and 2.8 mass% or less with respect to 100 mass% of the ink composition. More preferably, they are 0.5 mass% or more and 2.7 mass% or less, More preferably, they are 0.7 mass% or more and 2.5 mass% or less. When the content of the aromatic sulfonic acid formalin condensate is 0.1% by mass or more, the dispersion stability of the disperse dye can be ensured. Further, when the content of the aromatic sulfonic acid formalin condensate is 3% by mass or less, the disperse dye is not excessively dissolved and the viscosity can be kept small. In addition, the weight average molecular weight of the aromatic sulfonic acid formalin condensate is preferably in the range of 2000 to 12000 from the viewpoint of dispersion stability of the disperse dye and reduction of the viscosity of the ink.

1.3. Alkali Metal Compound The ink composition of the present embodiment contains an alkali metal compound. The molecular weight (molar mass) of the alkali metal compound used in this embodiment is 40 or more and 400. As such an alkali metal compound, an organic acid salt, inorganic acid salt, oxide, hydroxide, chloride, hydride or alcoholate of an alkali metal is preferable. More specifically, examples of the alkali metal compound include sodium hydroxide (40), potassium hydroxide (56), lithium hydroxide (24), sodium chloride (58), potassium chloride (76), and lithium chloride (24). Sodium bicarbonate (84), potassium bicarbonate (100), sodium carbonate (106), potassium carbonate (138), lithium carbonate (74), sodium acetate (82), potassium acetate (98), lithium acetate (66) Sodium sulfate (142), potassium sulfate (174), lithium sulfate (110), sodium stearate (306), potassium stearate (323), lithium stearate (290), sodium benzoate (144), potassium benzoate (160), lithium benzoate (128), disodium hydrogen phosphate (1 2), dipotassium hydrogen phosphate (174), dilithium hydrogen phosphate (103), sodium methanesulfonate (118), sodium benzenesulfonate (180), sodium salts of potassium, potassium salts, lithium salts, etc. Can be mentioned. In addition, the inside of the said parenthesis represents the approximate molecular weight (molar mass).

  In the ink composition of the present embodiment, two or more of these alkali metal compounds can be used in combination. Further, from the viewpoint of not making the pH of the ink composition too low, the alkali metal compound is preferably an alkali metal salt. More preferably, the alkali metal compound is a carboxylate or a sulfonate. More preferably, the alkali metal compound is preferably a sodium salt. It is particularly preferable that the alkali metal compound be at least one selected from the group consisting of sodium methanesulfonate, sodium acetate, sodium sulfate and sodium benzenesulfonate. The mechanism by which the foreign matter in the ink composition is suppressed by these compounds is not necessarily clear, but is proved by Examples and the like described later.

  The total content of the alkali metal compounds is 0.2% by mass or more and 4% by mass or less, preferably 0.3% by mass or more and 3% by mass or less, and more preferably 0.4% by mass with respect to 100% by mass of the ink composition. It is from 0.7% to 2% by mass, more preferably from 0.7% to 2.5% by mass. When the content of the alkali metal compound is 0.2% by mass or more, the dispersion stability of the disperse dye can be secured, and the dispersion of the disperse dye and the change in physical properties (viscosity, particle diameter) due to the aggregation can be suppressed. .

1.4. Alkali Metal Ion The ink composition of the present embodiment contains at least the above-mentioned aromatic sulfonic acid formalin condensate and an alkali metal compound. The alkali metal compound is ionized in the ink composition to generate an alkali metal ion. Moreover, also about the formalin condensate of aromatic sulfonic acid, when using an alkali metal salt, an alkali metal ion is produced | generated. Further, depending on the selection of other components (described later), alkali metal ions may be generated from the components. However, alkali metal ions in the ink composition of the present embodiment are mainly brought about by a formalin condensate of an aromatic sulfonic acid and / or an alkali metal compound. Moreover, it is more preferable that the alkali metal ion is a sodium ion in that it is excellent in the effect of suppressing the generation of acicular foreign matter and the dispersion stability (inhibition of aggregation) of the disperse dye. It is more preferable that the concentration of the alkali metal ion is adjusted by the blending amount of the alkali metal compound from the viewpoint of suppressing an increase in the viscosity of the ink composition.

The concentration of alkali metal ions in the ink composition of the present embodiment can be changed mainly by adjusting the blending amount of the aromatic sulfonic acid formalin condensate and / or alkali metal compound. The concentration of alkali metal ions in 100 g of the ink composition is 0.001 mol or more and 0.1 mol or less, preferably 0.002 mol or more and 0.08 mol or less, more preferably 0.005 mol or more and 0.05 mol or less, and still more preferably 0.00. It is 007 mol or more and 0.04 mol or less. The concentration of alkali metal ions in the ink composition can be determined by, for example, analysis by ion chromatography or a conductivity meter.

1.5. Other components 1.5.1. Colorant The ink composition according to the present embodiment may include a colorant other than the above-described disperse dye. Examples of such a color material include organic pigments, carbon black, oil-soluble dyes and the like as color materials insoluble or hardly soluble in an aqueous solvent. Carbon black, organic pigments, and oil-soluble dyes are more preferred because of good color development and low precipitation due to low specific gravity. In the ink composition of the present embodiment, the color material may be dispersed by a dispersion resin. Further, as the coloring material, a water-soluble acid dye, a direct dye, a reactive dye, a basic dye, or the like may be used.

  In the ink composition of the present embodiment, when the color material is dispersed with a dispersion resin, the ratio of the color material to the dispersion resin is preferably 10: 1 to 1:10, and more preferably 4: 1 to 1: 3. . Further, the volume average particle diameter of the colorant at the time of dispersion is such that the maximum particle diameter when measured by a dynamic light scattering method is less than 500 nm and the average particle diameter is 300 nm or less, more preferably the average particle diameter is 200 nm or less. is there.

1.5.2. Water The ink composition according to this embodiment contains water. Examples of water include water from which ionic impurities have been removed as much as possible, such as pure water such as ion exchange water, ultrafiltration water, reverse osmosis water, and distilled water, and ultrapure water. Further, when water sterilized by ultraviolet irradiation or addition of hydrogen peroxide is used, generation of bacteria and fungi can be prevented when the ink composition is stored for a long period of time.

  The water content is 30% by mass or more, preferably 40% by mass or more, more preferably 45% by mass or more, and further preferably 50% by mass or more, based on the total amount of the ink composition. The water in the ink composition includes, for example, a pigment dispersion used as a raw material, a resin particle dispersion, and water to be added. When the water content is 30% by mass or more, the ink composition can have a relatively low viscosity. Further, the upper limit of the water content is preferably 90% by mass or less, more preferably 85% by mass or less, and further preferably 80% by mass or less with respect to the total amount of the ink composition. In the present specification, the term “water-based ink” refers to an ink containing 30% by mass or more of water with respect to the total mass (100% by mass) of the ink.

1.5.3. Organic Solvent The ink composition of the present embodiment may contain an organic solvent. Examples of the organic solvent include water-soluble organic solvents, and examples thereof include glycol-based and glycol ether-based compounds.

Examples of water-soluble organic solvents include 1,2-pentanediol, methyl triglycol (triethylene glycol monomethyl ether), butyl triglycol (triethylene glycol monobutyl ether), butyl diglycol (diethylene glycol monobutyl ether), dipropylene glycol -Lumonopropyl ether, 1,2-hexanediol, 1,2-heptanediol, 2-methyl-3-phenoxy-1,2-propanediol, 3- (3-methylphenoxy) -1,2-propanediol, 3-hexyloxy-1,
2-propanediol and 2-hydroxymethyl-2-phenoxymethyl-1,3-propanediol, ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, polypropylene glycol, polyoxyethylene poly Glycols such as oxypropylene glycol, 1,3-propanediol, 1,2-butanediol, 1,2-pentanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, etc. Can be mentioned. A plurality of water-soluble organic solvents may be used in combination.

  The blending amount of the water-soluble organic solvent is 0.2% by mass or more and 30% by mass or less, preferably 0.4% by mass or more and 20% by mass or less, more preferably 0.5% by mass with respect to the total amount of the ink composition. It is 15 mass% or less, More preferably, it is 0.7 mass% or more and 10 mass% or less.

1.5.4. Surface Tension Adjusting Agent The ink composition of the present embodiment may contain a surface tension adjusting agent. As a surface tension adjuster, it is used to reduce the surface tension when dissolved in water and adjust the wettability of the ink to the substrate for printing and the discharge flow path. It is a low surface tension water-soluble solvent system and surfactant system. Chosen from. Examples of the water-soluble solvent system include lower alcohols such as ethanol, propanol and butanol, diols such as butylene glycol, 1,3-pentanediol, 2-ethyl-1,3-propanediol and 1,6-hexanediol. And glycol monoethers such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, and propylene glycol monomethyl ether.

  As the surfactant system, for example, a nonionic surfactant, an anionic surfactant, a cationic surfactant, and an amphoteric surfactant can be appropriately selected. Of these, acetylene glycol surfactants and silicone surfactants having high surface activity and low foaming properties are more preferred.

  Although it does not specifically limit as an acetylene glycol type surfactant, For example, Olfin E1004, E1010, E1020, PD-001, PD-002W, PD-004, PD-005, EXP. 4200, EXP. 4123, EXP. 4300 (trade name: manufactured by Nissin Chemical Industry Co., Ltd.), Surfinol 440, 465, 485, CT111, CT121, TG, GA, Dynol 604, 607 (trade name: Air Products Japan, Inc.) )), Acetylenol E40, E60, E100 (product names: manufactured by Kawaken Fine Chemical Co., Ltd.), E series such as Olfine 104 series and Olfine E1010 (trade name: manufactured by Air Products Japan, Inc.) And Surfynol 465 (trade name: manufactured by Nissin Chemical Industry CO., Ltd.).

  Examples of silicone surfactants include polysiloxane compounds and polyether-modified organosiloxanes. Although it does not specifically limit as a commercial item of a silicone type surfactant, Specifically, BYK-306, BYK-307, BYK-333, BYK-341, BYK-345, BYK-346, BYK-347, BYK -348, BYK-349 (trade name: manufactured by Big 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-6020, X-22-4515, KF-6011, KF-6012 (above trade names: manufactured by Shin-Etsu Chemical Co., Ltd.), Silface SAG002, 005, 503A, 008 (above Product name: manufactured by Nissin Chemical Industry Co., Ltd.).

  The blending amount of the surface tension adjusting agent is 0.01% by mass or more and 2% by mass or less, preferably 0.03% by mass or more and 2.5% by mass or less, more preferably 0.05% by mass with respect to the total amount of the ink composition. The mass is 2% by mass or more.

1.5.5. Humectant The ink composition of the present embodiment may contain a humectant. Any humectant can be used without particular limitation as long as it is generally used in an inkjet ink composition. The boiling point of the humectant is preferably 180 ° C. or higher, and more preferably 200 ° C. or higher. When the boiling point is within the above range, good water retention and wettability can be imparted to the ink composition.

  Specific examples of the humectant include diethylene glycol, triethylene glycol, tetraethylene glycol, pentamethylene glycol, trimethylene glycol, 2-butene-1,4-diol, 2-ethyl-1,3-hexanediol, and 2-methyl. -2,4-pentanediol, propylene glycol, dipropylene glycol, tripropylene glycol, isobutylene glycol, glycerin, diglycerin, mesoerythritol, trimethylolpropane, polyols such as pentaerythritol, dipentaerythritol, 2-pyrrolidone, N -Lactams such as methyl-2-pyrrolidone, ε-caprolactam, hydroxyethylpyrrolidone, urea derivatives such as urea, thiourea, ethyleneurea, 1,3-dimethylimidazolidinones Glucose, mannose, fructose, ribose, xylose, arabinose, galactose, aldonic acid, glucitol (sorbitol), maltose, cellobiose, lactose, sucrose, trehalose, maltotriose, monosaccharides, disaccharides, oligosaccharides and polysaccharides and these And glycine, trimethylglycine betaines, and the like.

  The blending amount when the moisturizing agent is blended with the ink composition of the present embodiment is 0.2% by mass or more and 30% by mass or less, preferably 0.4% by mass or more and 20% by mass with respect to the total amount of the ink composition. % Or less, more preferably 0.5% by mass or more and 15% by mass or less, and further preferably 0.7% by mass or more and 10% by mass or less.

1.5.6. pH adjuster The ink composition of this embodiment may contain a pH adjuster for the purpose of adjusting the pH. Although it does not specifically limit as a pH adjuster, For example, sulfuric acid, hydrochloric acid, nitric acid, etc. as an inorganic acid, lithium hydroxide, sodium hydroxide, potassium hydroxide, ammonia, etc. as an inorganic base, triethanolamine, diethanolamine as an organic base Monoethanolamine, triisopropanolamine, diisopropanolamine, trishydroxymethylaminomethane, organic acids such as adipic acid, citric acid, succinic acid, lactic acid, etc., pH buffer solution, phosphate buffer solution, citrate buffer solution, tris Examples include a buffer solution.

1.5.7. Other Components The ink composition according to this embodiment may be appropriately added with various additives such as preservatives, dissolution aids, viscosity modifiers, antioxidants, antifungal agents, chelating agents, and resin particles. it can.

1.6. Physical Properties of Ink Composition The ink composition according to this embodiment has a surface tension at 25 ° C. of 10 mN / m or more and 40 mN / m from the viewpoint of a balance between recording quality and reliability as an ink for ink jet recording. It is more preferable that it is 22 mN / m or more and 30 mN / m or less. The surface tension is measured by using an automatic surface tension meter CBVP-Z (manufactured by Kyowa Interface Science Co., Ltd.) by confirming the surface tension when the platinum plate is wetted with ink in an environment of 25 ° C. be able to.

  From the same viewpoint, the viscosity of the ink composition at 20 ° C. is preferably 2 mPa · s or more and 15 mPa · s or less, more preferably 2 mPa · s or more and 5 mPa · s or less, and 2 mPa · s or more. More preferably, it is 3.8 mPa · s or less. The viscosity is measured by using a viscoelasticity tester MCR-300 (manufactured by Pysica), increasing the Shear Rate to 10 to 1000 in an environment of 20 ° C., and reading the viscosity at Shear Rate 200. Can be measured.

1.6. Operational Effect The ink composition according to the present embodiment, despite containing a disperse dye, has reduced foreign matter generation, good storage stability and ejection stability, and low viscosity. That is, the formalin condensate of aromatic sulfonic acid can ensure the dispersibility of the disperse dye and suppress the generation of foreign matters by not excessively increasing the dissolution of the disperse dye. Moreover, aggregation of the disperse dye particles can be sufficiently reduced by increasing the concentration of alkali metal ions with the alkali metal compound. Furthermore, since the molecular weight of the alkali metal compound is 40 or more and 400 or less, the viscosity of the ink composition is not excessively increased, and can be suitably used for, for example, ink jet recording.

  In addition, when the ink composition is a light color ink, if the concentration of the dispersant (formalin condensate of aromatic sulfonic acid) is high, the ratio of the dispersant to the disperse dye increases and the disperse dye is easily dissolved. It is more preferable to reduce the concentration of the agent. In that case, the number of disperse dyes and the number of dispersant molecules in the ink composition are relatively decreased with respect to other components. As a result, the frequency of encounter between the disperse dye and the dispersant in the ink composition is reduced. As a result, the ratio of the disperse dye not adsorbed with the disperse agent in the entire disperse dye increases, and the dispersibility of the disperse dye is poor. Tend to be. On the other hand, in the ink composition of this embodiment, in such a case, the dispersibility of the disperse dye can be maintained high without increasing the concentration of the dispersant.

2. Inkjet recording apparatus The ink composition of the present embodiment can be suitably used in an inkjet recording apparatus. The ink jet recording apparatus has at least an ink container (cartridge, tank, etc.) for storing the above ink composition and a recording head connected thereto, and discharges the above ink composition from the recording head onto a recording medium. There is no particular limitation as long as an image can be formed.

  As the ink jet recording apparatus of this embodiment, either a serial type or a line type can be used. These types of ink jet recording apparatuses are equipped with a recording head. While changing the relative positional relationship between the recording medium and the recording head, droplets of the ink composition are ejected from the nozzle holes of the recording head. A predetermined image can be formed by ejecting at a timing (intermittently) and at a predetermined volume (mass) and adhering the ink composition to the recording medium.

  In general, in a serial type ink jet recording apparatus, the recording medium conveyance direction and the reciprocation direction of the recording head intersect, and the reciprocation operation of the recording head and the recording medium conveyance operation (including the reciprocation operation) The relative positional relationship between the recording medium and the recording head is changed by the combination. In this case, generally, a plurality of nozzle holes (holes for ejecting the ink composition) are arranged in the recording head, and a row of nozzle holes (nozzle row) is formed along the conveyance direction of the recording medium. Yes. Also, a plurality of nozzle rows may be formed on the recording head depending on the type and number of ink compositions.

  In general, in a line-type ink jet recording apparatus, the recording head does not reciprocate, and the relative positional relationship between the recording medium and the recording head is changed by conveying the recording medium, so that the recording medium and the recording head Change the relative positional relationship. Also in this case, generally, a plurality of nozzle holes are arranged in the recording head, and the nozzle hole array (nozzle array) is formed along the direction intersecting the recording medium conveyance direction.

  The ink jet recording system uses a serial type or line type ink jet recording apparatus as described above, and as the system, the ink composition is ejected as droplets from fine nozzle holes, and the droplets are recorded on the recording medium. If it can be made to adhere to, it will not be restrict | limited. For example, the ink jet recording method includes an electrostatic suction method, a method of ejecting ink droplets by pump pressure, a method of using a piezoelectric element, a method of heating and foaming an ink liquid with a microelectrode, and ejecting ink droplets, and the like. it can.

  For the ink jet recording apparatus used in the present embodiment, for example, known configurations such as a heating unit, a drying unit, a roll unit, and a winding device can be employed without limitation.

3. Examples and Comparative Examples Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to these examples.

3.1. Preparation of ink composition Each component was put into a container so as to have the composition shown in Table 1, mixed and stirred for 2 hours with a magnetic stirrer, and further into a bead mill filled with zirconia beads having a diameter of 0.3 mm. And mixed well by carrying out a dispersion treatment. After stirring for 1 hour, an ink composition according to Examples and Comparative Examples was obtained by filtering using a 5 μm PTFE membrane filter. The numerical values in Table 1 indicate mass%, and pure water (ion exchange water) was added so that the mass of each ink composition was 100 mass%.

  In the table, components other than the disperse dye used were purchased as reagents. In addition, the trade name: BYK-348 is a siloxane-based surfactant manufactured by Big Chemie Japan, and the formalin condensate (dispersant) of sodium naphthalenesulfonate is manufactured by Daiichi Kogyo Seiyaku Co., Ltd., product name: Labelin AN-40. Furthermore, as an alkali metal compound having a molecular weight exceeding 400, sodium alkylsulfosuccinate, manufactured by Nippon Emulsifier Co., Ltd .: trade name New Coal 293 (molecular weight 445) was used.

  In addition, among the raw materials of each ink composition, the generation species of alkali metal ions are only a formalin condensate (dispersant) of sodium naphthalenesulfonate or an alkali metal (sodium, potassium or lithium) compound. 1, the amount of alkali metal ions derived from the dispersant (sodium ion amount), the amount of alkali metal ions derived from the alkali metal compound, the amount of alkali metal ions in the entire ink composition, and the amount of sodium ions in the entire ink composition, respectively. Measured, calculated and written together.

3.2. Evaluation test 3.2.1. Viscosity of Ink Composition The viscosity at 25 ° C. of each ink composition obtained as described above was measured. Specifically, the viscosity at 20 ° C. of the ink composition is increased to 10 to 1000 in the environment of 20 ° C. using a viscoelasticity tester MCR-300 (manufactured by Pysica). It can be measured by reading the viscosity at a rate of 200 hours. Using an automatic surface tension meter CBVP-Z (manufactured by Kyowa Interface Science Co., Ltd.), the surface tension when the platinum plate was wetted with ink in an environment of 25 ° C. was measured according to the Wilhelmy method. And it evaluated by the following evaluation criteria and described in Table 1.
A: 3.8 mPa · s or less B: More than 3.8 mPa · s 5.0 mPa · s or less C: More than 5.0 mPa · s

3.2.2. Evaluation of foreign matter 10 g of the ink composition of each example was accommodated in an aluminum pack in a state where a gas-liquid interface was present, sealed, and left at 60 ° C. for 5 days. It was visually confirmed whether or not needle-like crystal foreign matter was generated in the ink composition after being left, and based on the confirmation result, the following evaluation criteria were used.
A: The number of needle-like foreign matters was 0. B: There were 0 needle-like foreign matters, but a slight amount of disperse dye aggregates was observed (acceptable level).
C: The number of acicular foreign matters was 10 or more. (Unacceptable level)

3.2.3. Evaluation of liquid contact of metal member The corrosivity of each ink composition was evaluated. Stainless steel was used as the target metal. Specifically, a stainless plate was prepared, and half of the plate was immersed in each ink composition. After leaving at 60 ° C. for 7 days, the stainless steel plate was washed with distilled water. Table 1 shows that the appearance of the immersed part and the non-immersed part is the same as "A", and that the gloss and color are slightly different are "B".

3.3. Evaluation results The above evaluation results are shown in Table 1. Looking at Examples 1 to 13 and Reference Example 1, if the concentration of alkali metal ions in 100 g of the ink composition is 0.005 (mol) or more and 0.05 (mol) or less, the generation of foreign matter is sufficiently suppressed. Turned out to be. Further, when Examples 1 to 6 and Reference Example 1 are viewed, the generation of foreign matter is sufficiently suppressed when the concentration of sodium ions in 100 g of the ink composition is 0.005 (mol) or more and 0.05 (mol) or less. Turned out to be.

  Further, in the case of a dark ink composition as in Reference Example 1 (the concentration of the disperse dye exceeds 4% by mass), it is considered that the concentration of sodium ions derived from the dispersant is sufficient, and the generation of foreign matters It is presumed that there was no. Moreover, since the amount of the dispersing agent with respect to the disperse dye was 1/3 or less, dissolution of the disperse dye by the dispersant was suppressed, and no foreign matter was observed.

In Comparative Examples 1 to 3, in the case of the light-color ink composition, even if the sodium ion derived from the dispersant (polymer) is increased, the generation of foreign matters cannot be suppressed, and the viscosity is It became clear that it was unsuitable for the inkjet method. In other words, from Comparative Examples 1 and 2, it was suggested that the amount of the dispersing agent added to such an extent that a viscosity suitable for the ink jet method can be secured cannot suppress the generation of foreign matters. Moreover, when the comparative example 3 was seen, when a dispersing agent was put excessively in order to eliminate a foreign material, it will be suggested that a dispersing agent melt | dissolves dye, a foreign material will generate | occur | produce, and also a viscosity will increase.
In Comparative Example 4, when an alkali metal compound having a molecular weight exceeding 400 was used as the alkali metal ion supply source, foreign matter was suppressed, but the viscosity increased, which was not preferable.

  In the ink compositions of Example 7 and Example 8 using potassium chloride and lithium chloride as the alkali metal compound, the occurrence of needle-like foreign matters was not observed, but a slight aggregation of the disperse dye was observed in the visual evaluation. It was. From this, it was found that the alkali metal ion provided by the alkali metal compound is more preferably a sodium ion.

  From the result of the evaluation of the metal part wetted liquid, it was found that when the alkali metal compound is an inorganic salt containing chlorine, some corrosive action (such as rust) tends to occur on the metal.

  The present invention is not limited to the above-described embodiments, and various modifications can be made. For example, the present invention includes substantially the same configuration (for example, a configuration having the same function, method and result, or a configuration having the same purpose and effect) as the configuration described in the embodiment. In addition, the invention includes a configuration in which a non-essential part of the configuration described in the embodiment is replaced. In addition, the present invention includes a configuration that exhibits the same operational effects as the configuration described in the embodiment or a configuration that can achieve the same object. In addition, the invention includes a configuration in which a known technique is added to the configuration described in the embodiment.

Claims (7)

With disperse dyes,
A formalin condensate of an aromatic sulfonic acid;
An alkali metal compound having a molecular weight of 40 or more and 400 or less;
water and,
An ink composition comprising: In claim 1,
The ink composition, wherein the concentration of alkali metal ions in 100 g of the ink composition is 0.005 mol or more and 0.05 mol or less. In claim 1 or claim 2,
The ink composition, wherein the alkali metal compound is an organic acid salt. In any one of Claims 1 thru | or 3,
The ink composition, wherein the alkali metal compound is a sodium salt. In claim 3 or claim 4,
The ink composition, wherein the organic acid salt is at least one selected from sodium methanesulfonate, sodium acetate, and sodium sulfate. In any one of Claims 1 thru | or 5,
The disperse dye is C.I. I. Disper thread 60 and C.I. I. An ink composition which is at least one of Disperse Orange 25. In any one of Claims 1 thru | or 6,
The ink composition, wherein the disperse dye content in the ink composition is 4% by mass or less.