Dispersant-containing liquids and inkjet compositions

Abstract

To provide a dispersion excellent in dispersion stability of a dispersoid and to provide a dispersant-containing liquid which can be suitably used for the preparation of the dispersion.SOLUTION: There is provided a dispersion containing a polyester as a dispersant, water, a dispersoid, wherein the polyester contains, as a monomer component, a first monomer having an aromatic ring in the side chain and a second monomer having at least one of a carboxyl group and a sulfo group which do not constitute an ester bond. The content of the first monomer relative to all monomers constituting the polyester is preferably 25 mol% or more and 75 mol% or less.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a dispersant-containing liquid and a dispersion liquid.

Background Art

[0002] A dispersion liquid in which a dispersion medium containing water has a dispersoid dispersed therein is used in various applications. Examples of such a dispersion liquid include ink in which a coloring material is dispersed in a dispersion medium containing water.

[0003] In such a dispersion liquid, a dispersant may be added for the purpose of improving the dispersibility of the dispersoid. For example, an inkjet recording dispersion dye ink containing water, a water-soluble organic solvent, a dispersion dye, and a water-soluble polyester having an acid value of 100 to 250 is known (see Patent Document 1).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, conventionally, it has been difficult to sufficiently improve the dispersion stability of the dispersoid in the dispersion liquid, particularly when the dispersoid is composed of a highly lipophilic material such as an organic dye such as a dispersion dye or an oil-soluble dye.

Means for Solving the Problems

[0006] The present invention has been made to solve the above problems and can be realized as the following application examples.

[0007] The dispersant-containing liquid according to an application example of the present invention comprises polyester as a dispersant and water. The polyester comprises, as monomer components, a first monomer having an aromatic ring in its side chain, and a second monomer having at least one of a carboxyl group and a sulfo group that do not constitute an ester bond.

[0008] The dispersion according to an example of the application of the present invention comprises polyester as a dispersant, water, and a dispersed phase. The polyester comprises, as monomer components, a first monomer having an aromatic ring in its side chain, and a second monomer having at least one of a carboxyl group and a sulfo group that do not constitute an ester bond. [Modes for carrying out the invention]

[0009] Preferred embodiments of the present invention will be described in detail below. <1> Dispersant-containing liquid First, the dispersant-containing liquid of the present invention will be described. The dispersant-containing liquid of the present invention comprises a polyester as a dispersant and water. The polyester comprises, as a monomer component, a first monomer having an aromatic ring in its side chain and a second monomer having at least one of a carboxyl group and a sulfo group that do not constitute an ester bond.

[0010] This configuration allows for excellent dispersion stability of the dispersed phase when a dispersion is prepared using a dispersant-containing liquid. In particular, it is possible to achieve excellent dispersion stability of the dispersed phase even in dispersions containing dispersed phases composed of highly lipophilic materials, such as organic dyes like disperse dyes and oil-soluble dyes. This effect is thought to be achieved for the following reasons: By including a polyester containing the first monomer and the second monomer as described above, it is possible to ensure sufficient adsorption to the highly hydrophobic dispersed phase while maintaining sufficiently high solubility of the polyester in water. As a result, it is thought that the dispersion stability of the dispersed phase in the dispersion can be stably maintained over a long period of time.

[0011] Conversely, if the above conditions are not met, satisfactory results cannot be obtained. For example, if the polyester used as a dispersant in the dispersant-containing liquid does not contain a first monomer having an aromatic ring in its side chain as a monomer component, the dispersion stability of the dispersed phase will be poor when a dispersion is prepared using the dispersant-containing liquid. In particular, in dispersions containing a dispersed phase composed of highly lipophilic materials such as disperse dyes and organic dyes such as oil-soluble dyes, the affinity between the polyester and the dispersed phase becomes very low, resulting in poor dispersion stability of the dispersed phase.

[0012] Furthermore, even when a monomer having an aromatic ring in its main chain is used instead of the first monomer, the dispersion stability of the dispersed phase cannot be sufficiently improved when a dispersion is prepared using a dispersant-containing liquid. In particular, in dispersions containing a dispersed phase composed of highly lipophilic materials such as disperse dyes and organic dyes such as oil-soluble dyes, the affinity between the polyester and the dispersed phase becomes low, and the dispersion stability of the dispersed phase cannot be sufficiently improved.

[0013] Furthermore, if the polyester used as a dispersant in the dispersant-containing liquid does not contain a second monomer as a monomer component that has at least one of a carboxyl group and a sulfo group that do not constitute an ester bond, the affinity of the polyester itself for water will be extremely low, making it impossible to dissolve or stably disperse the polyester in a water-containing composition. Therefore, the polyester cannot function as a dispersant.

[0014] <1-1>Water The dispersant-containing liquid of the present invention contains water. The water primarily functions to impart fluidity to the dispersant-containing liquid and the dispersion prepared using the dispersant-containing liquid, and thus functions as a dispersion medium and solvent. For the water used, it is preferable to use deionized water, pure water, or ultrapure water.

[0015] The lower limit of the water content in the dispersant-containing liquid is not particularly limited, but is preferably 30.0% by mass, more preferably 35.0% by mass, and even more preferably 40.0% by mass. The upper limit of the water content in the dispersant-containing liquid is not particularly limited, but is preferably 93.0% by mass, more preferably 90.0% by mass, and even more preferably 87.0% by mass.

[0016] This allows for more reliable adjustment of the viscosity of the dispersant-containing liquid to a suitable value. Furthermore, it improves the dispersion stability of the dispersed phase in the dispersion prepared using the dispersant-containing liquid.

[0017] <1-2> Polyester as a dispersant Polyester is a general term for polymer materials having ester bonds in their main chain, but generally it includes a chemical structure formed by the dehydration condensation of a polyol component having multiple hydroxyl groups in the molecule and a polycarboxylic acid component having multiple carboxyl groups in the molecule.

[0018] In particular, the dispersant-containing liquid of the present invention contains, as a monomer component, a polyester containing a first monomer having an aromatic ring in a side chain and a second monomer having at least one of a carboxyl group and a sulfo group that do not form an ester bond, as a dispersant.

[0019] The first monomer may be any monomer having an aromatic ring in a side chain, and may be a polyol component or a polycarboxylic acid component.

[0020] Examples of the aromatic ring contained in the side chain of the first monomer include a phenyl group, a biphenyl group, a naphthyl group, and the like.

[0021] Examples of the first monomer include phenylmalonic acid, phenylsuccinic acid, benzylmalonic acid, benzylsuccinic acid, phenylmethanediol, styreneglycol, 2-phenyl-1,3-propanediol, 3-phenyl-1,2-propanediol, 4-phenyl-1,2-butanediol, etc., and one or more selected from these can be used in combination.

[0022] The lower limit of the content of the first monomer with respect to all the monomers constituting the polyester is preferably 25 mol%, more preferably 30 mol%, and even more preferably 35 mol%. Also, the upper limit of the content of the first monomer with respect to all the monomers constituting the polyester is preferably 75 mol%, more preferably 70 mol%, and even more preferably 65 mol%.

[0023] This makes it possible to achieve a higher level of balance between the adsorption of polyester to the dispersed phase, particularly highly hydrophobic dispersed phases, and the affinity and solubility of polyester in water. This also improves the dispersion stability of the dispersed phase when a dispersion is prepared using a dispersant-containing liquid. Furthermore, when the dispersion is an inkjet composition, it is possible to improve the ejection stability of the inkjet composition by the inkjet method while also improving the color development of the recording area formed using the inkjet composition. In addition, it is possible to improve the water resistance of the recording area formed by the inkjet composition.

[0024] The second monomer may be any monomer having at least one of a carboxyl group and a sulfo group that do not constitute an ester bond, but it is preferable that the monomer has a sulfo group.

[0025] Furthermore, the second monomer may be a polyol component or a polycarboxylic acid component, but it is preferably a polycarboxylic acid component.

[0026] Examples of the second monomer having a carboxyl group that does not constitute an ester bond include trivalent or higher carboxylic acid compounds, their lower alkyl diesters, anhydrides, carboxyl group-containing polyols, and salts thereof, and one or more selected from these can be used in combination. Examples of the trivalent or higher carboxylic acid compounds include tricarbaryl acid, β-alanine diacetic acid, trimellitic acid, trimesic acid, pyromellitic acid, and merophanic acid. Examples of the carboxyl group-containing polyols include N,N-bis(2-hydroxyethyl)-β-alanine and N,N-bis(2-hydroxyethyl)succinamic acid. Furthermore, when a resin end modifier described later is used as the second monomer, for example, a divalent polycarboxylic acid monomer described later can be used as the resin end modifier.

[0027] Examples of the second monomer having a sulfo group include sulfonated polycarboxylic acid monomers, their lower alkyl esters, anhydrides, and sulfonated polyol monomers, and one or more selected from these can be used in combination. Examples of the sulfonated polycarboxylic acid monomers include sulfisophthalic acid, sulfoterephthalic acid, sulfophthalic acid, sulfosuccinic acid, sulfomaronic acid, 2,3-disulfosuccinic acid, sulfotartaric acid, sulfomalacic acid, sulfomaleic acid, sulfofumaric acid, 1-sulfo-1,2-cyclohexanedicarboxylic acid, and 3-(sodiooxysulfonyl)glutaric acid. Examples of the sulfonated polyol monomers include 2,3-dihydroxy-1-propanesulfonic acid, 3-[bis(2-hydroxyethyl)amino]-1-propanesulfonic acid, and 2-hydroxy-3-[bis(2-hydroxyethyl)amino]-1-propanesulfonic acid.

[0028] The lower limit of the content of the second monomer relative to the total monomers constituting the polyester is preferably 5 mol%, more preferably 7 mol%, and even more preferably 9 mol%. The upper limit of the content of the second monomer relative to the total monomers constituting the polyester is preferably 30 mol%, more preferably 28 mol%, and even more preferably 26 mol%.

[0029] This makes it possible to achieve a higher level of balance between the adsorption of polyester to the dispersed phase, particularly highly hydrophobic dispersed phases, and the affinity and solubility of polyester in water. This also improves the dispersion stability of the dispersed phase when a dispersion is prepared using a dispersant-containing liquid. Furthermore, when the dispersion is an inkjet composition, it is possible to improve the ejection stability of the inkjet composition by the inkjet method while also improving the color development of the recording area formed using the inkjet composition. In addition, it is possible to improve the water resistance of the recording area formed by the inkjet composition.

[0030] Furthermore, the lower limit of the ratio of the content of the second monomer to the content of the first monomer in the polyester is preferably 10%, more preferably 12%, and even more preferably 14% in molar ratio. Furthermore, the upper limit of the ratio of the content of the second monomer to the content of the first monomer in the polyester is preferably 80%, more preferably 75%, and even more preferably 70% in molar ratio.

[0031] This makes it possible to achieve a higher level of balance between the adsorption of polyester to the dispersed phase, particularly highly hydrophobic dispersed phases, and the affinity and solubility of polyester in water. This also improves the dispersion stability of the dispersed phase when a dispersion is prepared using a dispersant-containing liquid. Furthermore, when the dispersion is an inkjet composition, it is possible to improve the ejection stability of the inkjet composition by the inkjet method while also improving the color development of the recording area formed using the inkjet composition. In addition, it is possible to improve the water resistance of the recording area formed by the inkjet composition.

[0032] Carboxyl groups and sulfo groups that do not constitute an ester bond may, for example, be present in the side chains of the polyester molecule or at the ends of the main chain of the polyester.

[0033] If carboxyl groups that do not constitute an ester bond are present in the side chains of the polyester molecule, these carboxyl groups can be suitably introduced, for example, in the synthesis of the polyester by using trivalent or higher polycarboxylic acids, their lower alkyl esters, or acid anhydrides as polycarboxylic acid monomers, or by using compounds having two or more hydroxyl groups and one or more carboxyl groups as polyol monomers.

[0034] Furthermore, if carboxyl groups that do not constitute ester bonds are present at the ends of the polyester main chain, these carboxyl groups can be suitably introduced, for example, by synthesizing a polymer by adjusting the reaction conditions so that hydroxyl groups are present at the ends, and then reacting the hydroxyl groups at the ends of the polymer with carboxyl groups of a divalent or higher polycarboxylic acid monomer used as a resin end modifier. In this case, lower alkyl esters or acid anhydrides of the divalent or higher polycarboxylic acid monomer can also be used as the resin end modifier.

[0035] When a sulfo group is present in the side chain of the polyester molecule, the carboxyl group can be suitably introduced, for example, in the synthesis of the polyester by using a divalent or higher polycarboxylic acid having a sulfo group, its lower alkyl ester, or an acid anhydride as a polycarboxylic acid monomer, or by using a compound having a sulfo group and two or more hydroxyl groups as a polyol monomer.

[0036] Furthermore, if a sulfo group is present at the end of the polyester main chain, the sulfo group can be suitably introduced, for example, by synthesizing a polymer by adjusting the reaction conditions so that a hydroxyl group is present at the end, and then reacting the hydroxyl group at the end of the polymer with the carboxyl group of a resin end modifier having both a carboxyl group and a sulfo group.

[0037] Examples of polycarboxylic acid monomers include aromatic polycarboxylic acids such as phthalic acid, terephthalic acid, isophthalic acid, 2,5-norbornanedicarboxylic acid, 1,4-naphthalenedicarboxylic acid, biphenyldicarboxylic acid, 4,4'-sulfonyldibenzoic acid, and 2,5-naphthalenedicarboxylic acid; aliphatic polycarboxylic acids such as oxalic acid, malonic acid, glutaric acid, adipic acid, pimelic acid, azelaic acid, sebacic acid, fumaric acid, maleic acid, itaconic acid, 1,3-cyclopentanedicarboxylic acid, 1,2-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, and 1,4-cyclohexanedicarboxylic acid; and their lower alkyl esters and anhydrides. One or more selected from these can be used in combination.

[0038] Examples of polyol monomers include ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, polypropylene glycol, 1,3-propanediol, neopentyl glycol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 2,2,4-trimethyl-1,6-hexanediol, 1,2-cyclohexanedimethanol, and 1,3-cyclohexanedimethanol. Examples include aliphatic polyols such as 1,4-cyclohexanedimethanol and 2,2'-bis(4-hydroxycyclohexyl)isopropane, aromatic polyols such as 1,4-benzenedimethanol, 1,3-benzenedimethanol, 1,2-benzenedimethanol, biphenol, 4,4'-methylenebisphenol, 2,2-di(p-hydroxyphenyl)propane, styrene glycol, 2-phenyl-1,3-propanediol, and naphthalenediol, and one or more of these can be selected and used in combination.

[0039] The lower limit of the number-average molecular weight of the polyester is preferably 1,500, more preferably 1,800, and even more preferably 2,000. The upper limit of the number-average molecular weight of the polyester is preferably 10,000, more preferably 8,000, and even more preferably 7,000.

[0040] This configuration allows for improved water solubility of the polyester as a dispersant, and improves the dispersion stability of the dispersed phase when a dispersion is prepared using a dispersant-containing liquid. Furthermore, the viscosity of the dispersant-containing liquid and the dispersion prepared using the dispersant-containing liquid can be adjusted to a more suitable range. For example, if the dispersion is an inkjet composition, it is possible to improve the ejection stability of the inkjet composition by the inkjet method while also improving the color development of the recording section formed using the inkjet composition.

[0041] The lower limit of the polyester content in the dispersant-containing liquid is preferably 3.0% by mass, more preferably 4.0% by mass, and even more preferably 4.5% by mass. The upper limit of the polyester content in the dispersant-containing liquid is preferably 35.0% by mass, more preferably 30.0% by mass, and even more preferably 28.0% by mass.

[0042] This makes it easier to adjust the viscosity of the dispersant-containing liquid or the dispersion prepared using the dispersant-containing liquid to a suitable range, improving the ease of handling of the dispersant-containing liquid and the dispersion, and also improving the dispersion stability of the dispersed phase when a dispersion is prepared using the dispersant-containing liquid.

[0043] <1-3> Basic substances The dispersant-containing liquid of the present invention may further contain a basic substance in addition to the components described above.

[0044] This allows the pH range of the dispersant-containing solution to be adjusted to a suitable weakly basic range, ensuring a more favorable dissolution state of the polyester in the dispersant-containing solution. For example, problems such as aggregation and sedimentation due to the insolubilization of the polyester can be more effectively prevented. As a result, for example, when a dispersion is prepared using the dispersant-containing solution, the dispersion stability of the dispersed phase can be improved. Furthermore, if the dispersion is an inkjet composition, the ejection stability of the inkjet composition by the inkjet method can be improved.

[0045] Examples of basic substances include monovalent inorganic bases, divalent inorganic bases, and water-soluble organic amines, and one or more of these can be selected and used in combination.

[0046] Examples of monovalent inorganic bases include alkali metal hydroxides such as lithium hydroxide, sodium hydroxide, and potassium hydroxide, as well as ammonia. Alkali metal hydroxides are particularly preferred, and sodium hydroxide is more preferred. Examples of divalent inorganic bases include hydroxides of alkaline earth metals.

[0047] As water-soluble organic amines, for example, organic amines with a solubility in water at 20°C of 10 g / 100 g water or more can be used. Specific examples of water-soluble organic amines include alkylamines such as monoethylamine, diethylamine, triethylamine, monomethylamine, dimethylamine, and trimethylamine, as well as diethanolamine, triethanolamine, diisopropanolamine, triisopropanolamine, butyldiethanolamine, ethyldiethanolamine, and 2-amino-2-ethyl-1,3-propanediol.

[0048] In particular, hydroxyamines are preferred as water-soluble organic amines, diolamines or triolamines are more preferred, and triethanolamine is even more preferred.

[0049] This makes it possible to achieve particularly high water solubility of water-soluble organic amines, and improves the long-term stability of dispersions prepared using a dispersant-containing solution. Furthermore, it is possible to raise the boiling point of the dispersant-containing solution and the dispersions prepared using it, and also obtain high hygroscopicity, thereby more effectively preventing the precipitation of solids due to unintended drying of the dispersant-containing solution or dispersions.

[0050] Furthermore, the dispersant-containing solution preferably contains a monovalent inorganic base and a water-soluble organic amine as basic substances.

[0051] As a result, when forming a salt with the anionic polyester, the strong water solubility of the monovalent inorganic base salt and the affinity with additives used in the preparation of the dispersion using the water-soluble organic amine salt allow the polyester to be stably dissolved in the dispersion, thereby improving the long-term stability of the dispersion.

[0052] The basic substance may be used during the synthesis of the polyester, for example, so that the monomer is in the form of a salt, or it may be mixed with the synthesized polyester.

[0053] <1-4>Other ingredients The dispersant-containing liquid of the present invention may further contain components other than those described above. Hereinafter, such components will be referred to as "other components" in this section.

[0054] Other components include, for example, dispersants and resin components other than the polyester mentioned above, humectants, surface tension modifiers, preservatives, chelating agents, etc., and one or more of these can be selected and used in combination.

[0055] However, the dispersant-containing liquid of the present invention does not contain a dispersed phase. A dispersion containing a dispersed phase in addition to the components of the dispersant-containing liquid of the present invention described above is the dispersion liquid of the present invention described later.

[0056] Furthermore, the content of other components in the dispersant-containing liquid of the present invention is preferably 10.0% by mass or less, more preferably 5.0% by mass or less, and even more preferably 3.0% by mass or less.

[0057] <1-5> Others The dispersant-containing liquid of the present invention preferably satisfies the following conditions. For example, the lower limit of the pH of the dispersant-containing liquid of the present invention at 20°C is preferably 7.0, more preferably 7.2, and even more preferably 7.4. The upper limit of the pH of the dispersant-containing liquid of the present invention at 20°C is preferably 9.6, more preferably 9.0, and even more preferably 8.6.

[0058] This ensures a more favorable dissolution state for the polyester, and for example, it can more effectively prevent problems such as aggregation and sedimentation due to the insolubilization of the polyester. As a result, for example, when a dispersion is prepared using a dispersant-containing liquid, the dispersion stability of the dispersed phase can be improved. Furthermore, the drying resistance of the dispersion can also be improved. In addition, if the dispersion is an inkjet composition, the ejection stability of the inkjet composition by the inkjet method can be improved.

[0059] The dispersant-containing liquid of the present invention can be suitably prepared, for example, by adding necessary components such as a solvent containing the aforementioned polyol and water to the polyester obtained by the condensation reaction and stirring. Heating may also be performed during stirring as necessary.

[0060] <2> dispersion liquid Next, the dispersion of the present invention will be described.

[0061] The dispersion of the present invention comprises a polyester as a dispersant, water, and a dispersed phase. The polyester comprises, as monomer components, a first monomer having an aromatic ring in its side chain, and a second monomer having at least one of a carboxyl group and a sulfo group that do not constitute an ester bond.

[0062] This configuration allows for excellent dispersion stability of the dispersed phase in the dispersion. In particular, even in dispersions containing dispersed phases composed of highly lipophilic materials such as disperse dyes and organic dyes such as oil-soluble dyes, excellent dispersion stability of the dispersed phase can be achieved. This effect is thought to be due to the following reasons: By including a polyester containing the first monomer and the second monomer as described above, it is possible to ensure sufficient adsorption to the highly hydrophobic dispersed phase while maintaining sufficiently high solubility of the polyester in water. As a result, it is thought that the dispersion stability of the dispersed phase in the dispersion can be maintained stably over a long period of time.

[0063] <2-1>Water The dispersion of the present invention contains water. The water primarily serves to impart fluidity to the dispersion and functions as a dispersion medium and solvent. For the water used, it is preferable to use deionized water, pure water, or ultrapure water.

[0064] The lower limit of the water content in the dispersion is not particularly limited, but is preferably 35.0% by mass, more preferably 40.0% by mass, and even more preferably 45.0% by mass. The upper limit of the water content in the dispersant-containing solution is not particularly limited, but is preferably 93.0% by mass, more preferably 90.0% by mass, and even more preferably 87.0% by mass.

[0065] This allows for more reliable adjustment of the viscosity of the dispersion to a suitable value. Furthermore, it improves the dispersion stability of the dispersed phase within the dispersion.

[0066] <2-2> Polyester as a dispersant The dispersion of the present invention contains a polyester having carboxyl groups and sulfo groups that do not constitute ester bonds as a dispersant.

[0067] Such polyesters preferably satisfy the same conditions as described in <1-2> above. This will produce the same effect as described above.

[0068] The lower limit of the polyester content in the dispersion is preferably 0.3% by mass, more preferably 0.4% by mass, and even more preferably 0.5% by mass. The upper limit of the polyester content in the dispersion is preferably 20.0% by mass, more preferably 18.0% by mass, and even more preferably 16.0% by mass.

[0069] This makes it easier to adjust the viscosity of the dispersion to a suitable range, improving the ease of handling the dispersion and enhancing the dispersion stability of the dispersed phase.

[0070] Furthermore, the lower limit of the polyester content per 100.0 parts by mass of dispersed phase in the dispersion is preferably 10.0 parts by mass, more preferably 15.0 parts by mass, and even more preferably 20.0 parts by mass. Furthermore, the upper limit of the polyester content per 100.0 parts by mass of dispersed phase in the dispersion is preferably 200.0 parts by mass, more preferably 150.0 parts by mass, and even more preferably 130.0 parts by mass.

[0071] This makes it easier to adjust the viscosity of the dispersion to a suitable range, improving the ease of handling the dispersion and enhancing the dispersion stability of the dispersed phase.

[0072] <2-3>Dispersion The dispersion of the present invention contains a dispersed phase. The dispersed phase can be any substance that is dispersed in the dispersion, and can be composed of various materials depending on the application of the dispersion. Examples of constituent materials for the dispersed phase include resin materials that are poorly soluble in water, various organic colorants such as various organic pigments and dyes, and various inorganic colorants such as various inorganic pigments and dyes.

[0073] Examples of organic pigments include quinacridone pigments, quinacridone quinone pigments, dioxazine pigments, phthalocyanine pigments, anthrapyrimidine pigments, ancenthrone pigments, indanthrone pigments, flavanthrone pigments, perylene pigments, diketopyrrolopyrrole pigments, perinone pigments, quinophthalone pigments, anthraquinone pigments, thioindigo pigments, benzimidazolone pigments, isoindolinone pigments, azomethine pigments, azo pigments, and carbon black.

[0074] More specifically, examples of yellow pigments include CI Pigment Yellow 1, 2, 3, 4, 5, 6, 7, 10, 11, 12, 13, 14, 14C, 16, 17, 24, 34, 35, 37, 42, 53, 55, 65, 73, 74, 75, 81, 83, 93, 95, 97, 98, 100, 101, 104, 108, 109, 110, 114, 117, 120, 128, 129, 138, 150, 151, 153, 154, 180, etc. Examples of magenta pigments include CI Pigment Red 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 21, 22, 23, 30, 31, 32, 37, 38, 39, 40, 48(Ca), 48(Mn), 48:2, 48:3, 48:4, 49, 49:1, 50, 51, 52, 52:2, 53, 53:1, 55, 5 Examples of cyan pigments include 7(Ca), 57:1, 60, 60:1, 63:1, 63:2, 64, 64:1, 81, 83, 87, 88, 89, 90, 101, 104, 105, 106, 108, 112, 114, 122, 123, 146, 149, 163, 166, 168, 170, 172, 177, 178, 179, 184, 185, 190, 193, 202, 209, and 219. Examples of cyan pigments include CI Pigment Blue 1, 2, 3, 15, 15:1, 15:2, 15:3, 15:34, 16, 17:1, 22, 25, 56, 60, and CI Bat Blue 4, 60, and 63. Other color pigments include, for example, CI Pigment Orange 5, 13, 16, 17, 36, 43, 51; CI Pigment Green 1, 4, 7, 8, 10, 17, 18, 36; and CI Pigment Violet 1, 3, 5:1, 16, 19, 23, 38.

[0075] Examples of organic dyes include disperse dyes and oil-soluble dyes. Examples of disperse dyes include CI Disperse Red 60, 82, 86, 86:1, 167:1, 279, 364; CI Disperse Yellow 54, 64, 71, 86, 114, 153, 232, 233, 245; CI Disperse Blue 27, 60, 73, 77, 77:1, 87, 257, 359, 367; CI Disperse Violet 26, 33, 36, 57; and CI Disperse Orange 30, 41, 61.

[0076] Examples of oil-soluble dyes include CI Solvent Yellow 16, 21, 25, 29, 33, 51, 56, 82, 88, 89, 150, 163; CI Solvent Red 7, 8, 18, 24, 27, 49, 109, 122, 125, 127, 130, 132, 135, 218, 225, 230; CI Solvent Blue 14, 25, 35, 38, 48, 67, 68, 70, 132; and CI Solvent Black 3, 5, 7, 27, 28, 29, 34.

[0077] The dispersed phase contained in the dispersion of the present invention is preferably either a disperse dye or an oil-soluble dye.

[0078] This improves the affinity with the polyester containing the first monomer, and improves the dispersion stability of the dispersed phase in the dispersion. Furthermore, the dispersion of the present invention can be suitably applied to, for example, ink compositions, particularly inkjet compositions, and improves the color development and other properties of the recording section formed using the composition.

[0079] The content of the dispersed phase in the dispersion of the present invention is not particularly limited, but the lower limit of the content of the dispersed phase in the dispersion of the present invention is preferably 1.0% by mass, more preferably 2.0% by mass, and even more preferably 3.0% by mass. Furthermore, the upper limit of the content of the dispersed phase in the dispersion of the present invention is preferably 40.0% by mass, more preferably 35.0% by mass, and even more preferably 30.0% by mass.

[0080] This makes it possible to achieve a sufficiently high content of the dispersed phase in the dispersion while also improving the dispersion stability of the dispersed phase. Furthermore, when the dispersed phase is dispersed using a disperser such as a bead mill, for example, it becomes easier to adjust the viscosity of the resulting dispersion to a more suitable range. In addition, when the dispersion is an ink composition such as an inkjet composition, it is possible to improve the color development of the recording section formed using the ink composition.

[0081] <2-4> Basic substances In addition to the components described above, the dispersion of the present invention may further contain a basic substance.

[0082] This allows the pH range of the dispersion to be adjusted to a suitable range, ensuring a more favorable dissolution state of the polyester in the dispersion, and more effectively preventing problems such as aggregation and sedimentation due to the insolubilization of the polyester. As a result, for example, the dispersion stability of the dispersed phase in the dispersion can be improved. Furthermore, the drying resistance of the dispersion can be improved. In addition, if the dispersion is an inkjet composition, the ejection stability of the inkjet composition by the inkjet method can be improved.

[0083] Such basic substances are preferably those that satisfy the same conditions as described in <1-4> above. This will produce the same effect as described above.

[0084] <2-5> Moisturizer The dispersion of the present invention may contain a humectant.

[0085] As humectants, diethylene glycol, triethylene glycol, tetraethylene glycol, pentamethylene glycol, trimethylene glycol, 2-butene-1,4-diol, 2-ethyl-1,3-hexanediol, 2-methyl-2,4-pentanediol, tripropylene glycol, isobutylene glycol, propylene glycol, glycerin, diglycerin, mesoerythritol, trimethylolpropane, ditrimethylolpropane, pentaerythritol, dipene Examples include polyols such as taerythritol, monosaccharides such as 2-glucose, mannose, fructose, ribose, xylose, arabinose, galactose, aldonic acid, glucitol (sorbitol), maltose, cellobiose, lactose, sucrose, trehalose, maltotriose, disaccharides, oligosaccharides, polysaccharides, and derivatives of these sugars, as well as betaines such as glycine and trimethylglycine. One or more of these can be selected and used in combination.

[0086] The content of the humectant in the dispersion of the present invention is not particularly limited, but the lower limit of the humectant content in the dispersion of the present invention is preferably 3.0% by mass, more preferably 5.0% by mass, and even more preferably 7.0% by mass. Furthermore, the upper limit of the humectant content in the dispersion of the present invention is preferably 40.0% by mass, more preferably 35.0% by mass, and even more preferably 30.0% by mass.

[0087] <2-6> Surface tension modifier The dispersion of the present invention may contain a surface tension modifier. Examples of surface tension modifiers include surfactants and water-soluble compounds with a logP value in the range of greater than 0.0 and less than or equal to 4.0.

[0088] Examples of surfactants include cationic surfactants, anionic surfactants, and nonionic surfactants. However, nonionic surfactants are particularly preferred in order to minimize the influence on the solubility of the polyester which is dissolved by anionic surfactants.

[0089] Examples of nonionic, nonreactive surfactants include silicone-based surfactants, fluorine-based surfactants, and acetylene glycol-based surfactants.

[0090] Examples of silicone-based surfactants include: BYK-306, BYK-307, BYK-333, BYK-341, BYK-345, BYK-346, BYK-348, BYK-349, BYK-3455 from BIC Chemie Japan; Silface SAG503A, SAG002, SAG005, SAG014 from Nisshin Chemical Industry Co., Ltd.; and 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 from Shin-Etsu Chemical Co., Ltd.

[0091] Examples of fluorine-based surfactants include FC-4430 and FC-4432 from 3M Japan, Megafac F-444, F-477, F-553, and F-556 from DIC Corporation, and Surflon S-241, S-242, S-243, and S-386 from AGC Seimi Chemical Co., Ltd.

[0092] Examples of acetylene glycol-based surfactants include Surfinol 82, 465, 485, 2502, Olfin E1010, E1020, PD-002W, PD-004, EXP4001, EXP4002, EXP4123, EXP4300 from Nisshin Chemical Industry Co., Ltd., and Acetylenel E00, E103T, E40, E60, E100, E200 from Kawaken Fine Chemical Co., Ltd.

[0093] Examples of water-soluble compounds with a logP value greater than 0.0 and less than or equal to 4.0 include lower alcohols such as 2-propanol (logP 0.05), 1-propanol (logP 0.25), 2-butanol (logP 0.6), and 1-butanol (logP 0.88); glycol monoethers such as diethylene glycol monobutyl ether (logP 0.4), triethylene glycol monobutyl ether (logP 0.5), propylene glycol monobutyl ether (logP 1.2), dipropylene glycol monobutyl ether (logP 1.5), ethylene glycol mono-2-ethylhexyl ether (logP 2.8), and diethylene glycol mono-2-ethylhexyl (logP 2.4); lower alkyl 1,2-diols such as 1,2-pentanediol (logP 0.06) and 1,2-hexanediol (logP 0.6); and glycerin monobutyl ether (logP Examples include glycerin monoethers such as glycerin-2-ethylhexyl ether (logP 2.5), 0.6), and glycerin-2-ethylhexyl ether (logP 2.5).

[0094] The content of the surface tension modifier in the dispersion of the present invention is not particularly limited, but the lower limit of the content of the surface tension modifier in the dispersion of the present invention is preferably 0.1% by mass, more preferably 0.3% by mass, and even more preferably 1.0% by mass. Furthermore, the upper limit of the content of the surface tension modifier in the dispersion of the present invention is preferably 10.0% by mass, more preferably 8.0% by mass, and even more preferably 7.0% by mass.

[0095] <2-7> Other ingredients The dispersion of the present invention may further contain components other than those described above. Hereinafter, such components will be referred to as "other components" in this section.

[0096] Other components include, for example, preservatives, chelating agents, dispersants other than the polyester, and resin components, and one or more of these can be selected and used in combination.

[0097] By including preservatives, for example, spoilage of the dispersion by microorganisms can be prevented, and the precipitation and aggregation of solids in the dispersion can be more effectively prevented. Examples of preservatives include methylisothiazolinone, chloromethylisothiazolinone, octylisothiazolinone, dichlorooctylisothiazolinone, benzisothiazolinone, dicyclohexylamine, iodide propynyl butylcarbamate, and diethylene oxidide.

[0098] By including a chelating agent, for example, polyvalent cations in the dispersion can be trapped, making it possible to more effectively prevent the precipitation and aggregation of solid components in the dispersion.

[0099] Examples of chelating agents include ethylenediaminetetratetraacetate, diethyltriaminepentaacetate, pentetate, iminodisuccinate, and aspartate diacetate.

[0100] However, the content of other components in the dispersion of the present invention is preferably 10.0% by mass or less, more preferably 5.0% by mass or less, and even more preferably 3.0% by mass or less.

[0101] <2-8> Others The dispersion of the present invention preferably satisfies the following conditions. For example, the lower limit of the pH of the dispersion of the present invention at 20°C is preferably 7.0, more preferably 7.2, and even more preferably 7.4. The upper limit of the pH of the dispersion of the present invention at 20°C is preferably 9.6, more preferably 9.0, and even more preferably 8.6.

[0102] This ensures a more favorable dissolution state for the polyester, and for example, it can more effectively prevent problems such as aggregation and sedimentation due to the insolubilization of the polyester. As a result, for example, the dispersion stability of the dispersed phase in the dispersion can be improved. The drying resistance of the dispersion can also be improved. Furthermore, if the dispersion is an inkjet composition, the ejection stability of the inkjet composition by the inkjet method can be improved.

[0103] The dispersion of the present invention may be used for any purpose, such as paints or various ink compositions, but it is preferably an inkjet composition.

[0104] In inkjet compositions, sedimentation and aggregation of the dispersed phase, or precipitation of solid components within the inkjet head or flow path, significantly affect the ejection stability by the inkjet method, and in some cases, may even make it impossible to eject the composition by inkjet. In other words, inkjet compositions require a higher level of dispersion stability of the dispersed phase. In response to this, the present invention makes it possible to achieve particularly excellent dispersion stability of the dispersed phase. That is, the effects of the present invention are more pronounced when the dispersion is an inkjet composition. In this specification, the term "inkjet composition" includes not only the inkjet ink itself ejected by the inkjet method, but also, for example, the stock solution of inkjet ink used in the preparation of an inkjet by mixing it with other components.

[0105] The lower limit of the viscosity of the dispersion of the present invention at 20°C is not particularly limited, but is preferably 2.0 mPa·s, more preferably 3.0 mPa·s, and even more preferably 4.0 mPa·s. The upper limit of the viscosity of the dispersion of the present invention at 20°C is not particularly limited, but is preferably 9.0 mPa·s, more preferably 8.0 mPa·s, and even more preferably 7.0 mPa·s. This makes it possible to improve the discharge stability of the dispersion liquid of the present invention, for example, when it is an inkjet composition.

[0106] The viscosity was measured at 20°C using, for example, an Anton Paar MCR102 rheometer, with a shear rate of 10[s]. -1 ] to 1000[s -1 The viscosity can be measured by increasing the setting and reading the viscosity when the Shear Rate is 200.

[0107] The lower limit of the surface tension of the dispersion of the present invention at 20°C is not particularly limited, but is preferably 20 mN / m, more preferably 21 mN / m, and even more preferably 23 mN / m. The upper limit of the surface tension of the dispersion of the present invention at 20°C is not particularly limited, but is preferably 50 mN / m, more preferably 40 mN / m, and even more preferably 30 mN / m.

[0108] As a result, for example, when the dispersion of the present invention is an inkjet composition, clogging of the nozzles of an inkjet recording device becomes less likely, and the discharge stability of the dispersion of the present invention is further improved. Furthermore, even if nozzle clogging occurs, the ability to recover by capping the nozzle, i.e., by capping, can be improved.

[0109] Furthermore, the surface tension can be measured using the Wilhelmy method. For measuring surface tension, a surface tension meter such as the CBVP-7 manufactured by Kyowa Interface Science Co., Ltd. can be used.

[0110] When the dispersion of the present invention is an inkjet ink, the ink is typically stored in a container such as a cartridge, bag, or tank and applied to an inkjet recording device. In other words, the recording device according to the present invention is equipped with a container such as an ink cartridge that stores the inkjet ink as the dispersion of the present invention.

[0111] The dispersion of the present invention can be prepared, for example, by mixing the dispersant-containing liquid of the present invention described above with a substance to be dispersed.

[0112] At this time, a bead mill or the like may be used with the dispersant-containing liquid of the present invention and the substance to be dispersed mixed together. This allows for efficient micronization of the substance to be dispersed, thereby improving the dispersion stability of the dispersed substance in the dispersion liquid of the present invention.

[0113] Various inorganic beads such as zirconia beads, stainless steel beads, and alumina beads can be suitably used as beads.

[0114] When preparing the dispersion of the present invention, in addition to the dispersant-containing liquid and the substance to be dispersed as described above, components such as water, solvents, humectants, and surface tension modifiers may also be used. When preparing the dispersion of the present invention, heating may be performed as needed.

[0115] Furthermore, the dispersion of the present invention is not limited to those prepared by the method described above. For example, the dispersion of the present invention may be prepared without using the dispersant-containing liquid of the present invention described above, by mixing the polyester obtained by the condensation reaction, the substance to be formed into the dispersion, the solvent containing the polyol described above, water, and other necessary components all at once, or by adding and mixing them sequentially in a predetermined order.

[0116] Although preferred embodiments of the present invention have been described above, the present invention is not limited thereto. [Examples]

[0117] Next, specific embodiments of the present invention will be described. <3> Polyester synthesis

[0118] (Synthesis Example 1) In a 500 mL separable flask equipped with a stirrer, 49.0 parts by mass of phenylsuccinic acid, 15.0 parts by mass of succinic anhydride, 27.0 parts by mass of 5-sulfoisophthalic acid, 31.0 parts by mass of ethylene glycol, and 4.6 parts by mass of tetrabutoxytitanium were added as polycarboxylic acids having aromatic rings in their side chains. The mixture was heated at 180°C for 3 hours, and then heated under reduced pressure at 220°C for 5 hours while removing volatile components to obtain a polyester as a dispersant.

[0119] (Synthesis Examples 2-10) Polyester was obtained in the same manner as in Synthesis Example 1, except that the type and amount of raw material monomers used for polyester synthesis were changed as shown in Table 1.

[0120] Table 1 summarizes the conditions of the polyesters obtained in Synthesis Examples 1 to 10. The values ​​for "Components Used in Synthesis" in Table 1 represent the amount of each component used in parts by mass. In Table 1, phenylsuccinic acid is abbreviated as "PSA," benzylsuccinic acid as "BSA," dimethyl terephthalate as "TPA," dimethyl isophthalate as "IPA," succinic anhydride as "SA," 5-sulfoisophthalic acid as "SIPA," trimellitic acid as "TMA," styrene glycol as "SG," bisphenol A as "BisA," and ethylene glycol as "EG." Furthermore, the number-average molecular weight of the polyesters obtained in Synthesis Examples 1 to 8 was within the range of 1,500 to 10,000. Furthermore, in all of the polyesters obtained in Synthesis Examples 1 to 8, the content of the first monomer relative to the total monomers constituting the polyester was in the range of 25 mol% to 75 mol%, and the content of the second monomer relative to the total monomers constituting the polyester was in the range of 5 mol% to 30 mol%. In addition, in all of the polyesters obtained in Synthesis Examples 1 to 8, the ratio of the content of the second monomer to the content of the first monomer in the polyester was in the range of 10% to 80% in molar ratio.

[0121] The number-average molecular weight of the obtained polyester was measured by GPC. Furthermore, the monomer ratio in the polyester was: 1 The amount of sulfo groups was measured by 1H-NMR. The amount of sulfo groups was calculated by measuring the sulfur content using XRF. The amount of carboxyl groups was calculated from the acid value of the polyester.

[0122] [Table 1]

[0123] <4> Preparation of a dispersant-containing solution (Example A1) In a flask, 17.6 parts by mass of polyester, 0.3 parts by mass of triethanolamine, and 50.0 parts by mass of pure water were added. Then, pure water was added to bring the total volume to 100.0 parts by mass to obtain a dispersant-containing solution.

[0124] (Examples A2-A8) The dispersant-containing solution was prepared in the same manner as in Example A1, except that the type of polyester used, and the amounts of triethanolamine and pure water used were changed as shown in Table 2.

[0125] (Comparative Example A1) The dispersant-containing solution was prepared in the same manner as in Example A1, except that the type of polyester used, and the amounts of triethanolamine and pure water used were changed as shown in Table 2.

[0126] (Comparative example A2) Except for changing the type of polyester used and the amounts of triethanolamine and pure water used in the preparation of the dispersant-containing solution as shown in Table 2, an attempt was made to prepare the dispersant-containing solution in the same manner as in Example A1. However, in this comparative example, the polyester did not dissolve, so it was not possible to obtain the dispersion medium-containing solution as a solution in which the polyester as a dispersant was dissolved.

[0127] Table 2 summarizes the conditions of the dispersant-containing solutions for each of the above examples and comparative examples. The numerical values ​​for "Amount Used" under "Components Used in Preparation" in Table 2 represent the amount of each component used in parts by mass. In Table 2, triethanolamine is indicated as "TEA".

[0128] [Table 2]

[0129] <5> Preparation of inkjet ink concentrate as a dispersion (Example B1) To 85.0 parts by mass of the dispersant-containing liquid prepared in Example A1, 15.0 parts by mass of CI Disperse Red 60, a disperse dye, was added as a colorant. The mixture was dispersed for 6 hours in a bead mill using zirconia balls as a medium, the beads were separated, and the mixture was filtered through a membrane filter with a pore size of 5 μm to obtain a stock solution for inkjet ink as a dispersion.

[0130] (Examples B2-B12) The inkjet ink stock solution was prepared in the same manner as in Example B1, except that the type of dispersant-containing liquid and the type of colorant used in preparing the inkjet ink stock solution were changed as shown in Table 3.

[0131] (Comparative examples B1 and B2) The inkjet ink stock solution was prepared in the same manner as in Example B1, except that the type of dispersant-containing liquid used to prepare the inkjet ink stock solution was changed as shown in Table 3.

[0132] Table 3 summarizes the conditions of the inkjet ink stock solutions for each of the above examples and comparative examples. In Table 3, the values ​​for "Amount Used" under "Components Used in Preparation" indicate the amount of each component used in parts by mass. In Table 3, CI Disperse Red 60 is abbreviated as "DR60", CI Disperse Yellow 54 as "DY54", CI Disperse Blue 359 as "DB359", CI Pigment Red 122 as "PR122", and CI Pigment Yellow 74 as "PY74". The pH of the inkjet ink stock solutions for each of the above examples at 20°C was within the range of 7.0 to 9.0.

[0133] [Table 3]

[0134] <6> Preparation of inkjet ink as a dispersion (Example C1) 30.0 parts by mass of the inkjet ink stock solution prepared in Example B1, 5.0 parts by mass of propylene glycol as a humectant, 7.0 parts by mass of glycerin, 5.0 parts by mass of diethylene glycol, 5.0 parts by mass of butyl triglycol as a surface tension modifier, 0.5 parts by mass of Olfin E1010 (manufactured by Nisshin Chemical Industry Co., Ltd.), and 0.5 parts by mass of BYK-348 (manufactured by Bic Chemie Japan Co., Ltd.) were mixed. Then, pure water was added to bring the total volume to 100.0 parts by mass, the mixture was stirred for 30 minutes at 20°C, and filtered through a membrane filter with a pore size of 5 μm to obtain an inkjet ink dispersion.

[0135] (Examples C2-C12) An inkjet ink dispersion was prepared in the same manner as in Example C1, except that the type of inkjet ink stock used for preparing the inkjet ink was changed as shown in Table 4.

[0136] (Comparative Example C1) An inkjet ink dispersion was prepared in the same manner as in Example C1, except that the type of inkjet ink stock used for preparing the inkjet ink was changed as shown in Table 4.

[0137] Table 4 summarizes the conditions of the inkjet inks for each of the above examples and comparative examples. The values ​​for "Amount Used" under "Components Used in Preparation" in Table 4 represent the amount of each component used in parts by mass. In Table 4, propylene glycol is abbreviated as "PG," glycerin as "GL," diethylene glycol as "DEG," and butyl triglycol as "BTG." The pH of the inkjet inks for each of the above examples at 20°C was within the range of 7.0 to 9.0. Furthermore, the viscosity of the inkjet inks for each of the above examples was between 2.0 mPa·s and 9.0 mPa·s. Viscosity was measured using an Anton Paar MCR102 rheometer at 20°C with a shear rate of 10 [s]. -1 ] to 1000[s -1 The viscosity was measured by increasing the viscosity and reading the value when the shear rate reached 200. In addition, the surface tension of the inkjet inks in each of the above examples was within the range of 23 mN / m to 30 mN / m. The surface tension was measured using a surface tensimeter (CBVP-7, manufactured by Kyowa Interface Science Co., Ltd.) at 20°C by the Wilhelmy method.

[0138] [Table 4]

[0139] <7> evaluation <7-1> Evaluation of storage stability based on viscosity stability The undiluted inkjet inks of Examples B1 to B12 and Comparative Example B1, as well as the inkjet inks of Examples C1 to C12 and Comparative Example C1, were each placed in sample containers and left at 70°C for 10 days. The viscosity at 20°C was then measured and compared with the viscosity at 20°C of the inkjet ink immediately after manufacturing, and evaluated according to the following criteria. A smaller viscosity fluctuation rate indicates better dispersion stability of the dispersed phase.

[0140] A: Viscosity fluctuation rate from immediately after manufacturing is less than 10%. B: Viscosity fluctuation rate from immediately after manufacturing is 10% or more but less than 20%. C: Viscosity fluctuation rate from immediately after manufacturing is 20% or more. D: Aggregation and gelation occur, making viscosity measurement impossible.

[0141] <7-2> Evaluation of storage stability based on particle size stability The stock inkjet inks of Examples B1 to B12 and Comparative Example B1, as well as the inkjet inks of Examples C1 to C12 and Comparative Example C1, were each placed in sample containers and left at 70°C for 10 days. After that, the average particle size of the dispersed phase contained in the inkjet ink was determined at 20°C and compared with the average particle size of the dispersed phase contained in the inkjet ink immediately after manufacturing, and evaluated according to the following criteria. The smaller the rate of variation in the particle size of the dispersed phase, the better the dispersion stability of the dispersed phase. In this specification, unless otherwise specified, the average particle size refers to the average particle size based on volume. The average particle size was determined by measurement using the zeta potential / particle size measuring device ELSZ-1000 manufactured by Otsuka Electronics Co., Ltd.

[0142] A: The variation rate of the average particle size of the dispersed phase immediately after manufacturing is less than 15%. B: The variation rate of the average particle size of the dispersed phase from immediately after manufacturing is 15% or more but less than 30%. C: The variation rate of the average particle size of the dispersed phase from immediately after manufacturing is 30% or more. D: Aggregation and gelation occur, making it impossible to measure the particle size of the dispersed phase. The evaluation results described above are summarized in Table 5.

[0143] [Table 5]

[0144] As is clear from Table 5, the present invention exhibited excellent storage stability. In contrast, the comparative example showed poor storage stability, and satisfactory results could not be obtained.

Claims

1. It contains polyester as a dispersant and water. The polyester comprises, as monomer components, a first monomer having an aromatic ring in its side chain, and a second monomer having at least one of a carboxyl group and a sulfo group that do not constitute an ester bond. A dispersant-containing liquid for inkjet compositions, wherein the content of the first monomer relative to the total monomers constituting the polyester is 25 mol% or more and 75 mol% or less.

2. The dispersant-containing liquid according to claim 1, wherein the content of the second monomer relative to the total monomers constituting the polyester is 5 mol% or more and 30 mol% or less.

3. The dispersant-containing liquid according to claim 1 or 2, wherein the ratio of the content of the second monomer to the content of the first monomer in the polyester is 10% or more and 80% or less in molar ratio.

4. The dispersant-containing liquid according to claim 1, further comprising a monovalent inorganic base and a water-soluble organic amine.

5. The dispersant-containing liquid according to claim 4, wherein the water-soluble organic amine is a hydroxyamine.

6. It contains polyester as a dispersant, water, and a dispersed phase. The polyester comprises, as monomer components, a first monomer having an aromatic ring in its side chain, and a second monomer having at least one of a carboxyl group and a sulfo group that do not constitute an ester bond. An inkjet composition in which the content of the first monomer relative to the total monomers constituting the polyester is 25 mol% or more and 75 mol% or less.

7. The inkjet composition according to claim 6, wherein the dispersed phase is either a disperse dye or an oil-soluble dye.

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